key: cord-027713-8ohchx8p authors: abidine, m’hamed bilal; fergani, belkacem title: human activities recognition in android smartphone using wsvm-hmm classifier date: 2020-05-31 journal: the impact of digital technologies on public health in developed and developing countries doi: 10.1007/978-3-030-51517-1_35 sha: doc_id: 27713 cord_uid: 8ohchx8p being able to recognize human activities is essential for several applications such as health monitoring, fall detection, context-aware mobile applications. in this work, we perform the recognition of the human activity based on the combined weighted svm and hmm by taking advantage of the relative strengths of these two classification paradigms. one significant advantage in wsvms is that, they deal the problem of imbalanced data but his drawback is that, they are inherently static classifiers they do not implicitly model temporal evolution of data. hmms have the advantage of being able to handle dynamic data with certain assumptions about stationary and independence. the experiment results on real datasets show that the proposed method possess the better robustness and distinction. the advancement of technologies has facilitated the monitoring of human activities through the embedded sensors in a smartphone. recently, smart phones, equipped with a rich set of sensors, are explored as alternative platforms for human activity recognition (har) [1, 2] . har technology aims at recognizing the behavior and activities of users through a series of observations, which has wide application [3, 4] in different areas, such as healthcare and military monitoring. with smartphones becoming an integral part of daily human life [5] , they are being preferred as the most usable appliances that could recognize human activities due to its powerful in terms of mobility, user-friendly interface, network capability, strong cpu, memory, and battery. they contain a large number of hardware sensors such as accelerometer, gyroscope, temperature, humidity, light sensor, and gps receiver. the human sensor based activity recognition is a combination of sensor networks hand-in-hand with the data mining and machine learning techniques [6] . the smartphones provide enormous amount of sensor data for one to understand the daily activity patterns of an individual. the basic procedure for mobile activity recognition involves i) collection of labelled data, i.e., associated with a specific class or activity from users that perform sample activities to be recognized ii) classification model generation by using collected data to train and test classification algorithms iii) a model deployment stage where the learnt model is transferred to the mobile device for identifying new contiguous portions of sensor data streams that cover various activities of interest. sensor data can be processed in real-time or logged for offline analysis and evaluation. the model generation is usually performed offline on a server system and later deployed to the phone to recognize the activity performed. recently, several authors [7, 8] have proposed many applications related to activity recognition on multiple body positions. most of the work, like ahmad [9] , tran [10] , awan [11] , shoaib [12] , and abidine [13] , consider a single classifier approach to study activity recognition using smartphones. for the classification, svms are popular [8, 14] . it is also the case for hmms [15] which they commonly used for time-series activity recognition. however, there is very limited number of publications in the literature that investigate the application of the wsvm classifier for smartphone data, and no one is found about applying the latter one on smartphone data or even on har system's datasets. building a system with high precision to accurately identify these activities is a challenging task. in this work, we adopted a new method for physical activity recognition using mobile phones that uses labels outputting wsvm in hmm. wsvm investigated the effect of overweighting the minority class on svm modeling between the performed activities. hmm is a natural solution to address the activity complexity bycapturing and smoothing information during the transition between two activities (e.g. walking and standing). we also used the feature extraction approach that transforms the original high dimensional data to a lower dimensional feature space. the transformation can be linear or nonlinear. in this project, we employed the linear principal component analysis (pca) [16] to extract the feature vectors. figure 1 shows the architecture of the proposed activity recognition system. among the available labelled data, training and test subsets are chosen using the crossvalidation mechanism. the constructed pca space is then used for training and testing the weighted svm classifier. in the second step of the process is a pre-classification by 'wsvm', this phase is carried out by the 'cross-validation' will generate an estimate of the label vector. the principal component features concatenated with the wsvm estimated label vector are employed as a new training data to train hmm classifier. the final classification is performed with the 'viterbi' algorithm, by the use of a hmm model. an estimated label vector is generated by the 'viterbi' algorithm and the system will output the recognized activity (i.e., walking, running, and others). pca [16] is an orthogonal projection-based technique such that the variance of the projected data is maximized. in our case, a large number of features are extracted by prepossessing the raw signals generated from different sensors. it is a widely used technique for dimensionality reduction, feature extraction, and data visualization through the construction of uncorrelated principal components that are a linear combination of the original variables. the pca components can be counted by performing the eigenvector decomposition of the covariance matrix s: this problem leads to solve the eigenvalue equation with k is the eigenvalue of s and v is the eigenvector corresponding to the k: ð2þ is the n â n matrix containing n eigenvectors and k is an n â n diagonal matrix of eigenvalues of the covariance matrix. in eq. (2), each n dimensional eigenvector v i corresponds to the ith eigenvalue k i . osuna et al. [17] proposed an extension of the svm modeling, weighted svm algorithm to overcome the imbalance problem by introducing two different penalty parameter c à and c þ in the primal lagrangian (eq. 3) for the minority (y i = −1) and majority classes (y i = +1), as follow m þ (resp. m à ) the number of positive (resp. negative) instances in the initial database ( m à þ m þ ¼ m). solving the formulation dual of wsvm [17] gives a decision function for classifying a test point y 2 r p f ðxþ ¼ sgn we used the gaussian kernel as follows: kðx; yþ ¼ exp à x à y k k 2 =2r 2 . some authors [17] [18] [19] have proposed adjusting different cost parameters to solve the imbalanced problem. to extend weighted svm to the multi-class scenario in order to deal with n classes (daily activities), we have shown in [20] that the cost of misclassifying a point from the small class should be heavier than the cost for errors on the large class. they used different misclassification c i per class, use this conclusion can get a satisfactory result. by taking c − = c i and c + = c, with m þ and m i be the number of samples of majority classes and number of samples in the i th class, the main ratio cost value c i for each activity can be obtained by: hmm [21] comprises two parts: markov chain and stochastic process. markov chain, whose output is a sequence of state, can be described by the initial probability distribution for the states (p) and the state transition matrix (a), while stochastic process whose output is a sequence of observed values, is described by the observation probability matrix (b). thus, a hmm can be described as: with: i, j {1,2, …, n} o t : vector of observations a standard hmm is a generative probabilistic model, which generates hidden states y t from observable data x t at each discrete time instant. in our case the hidden variable is the activities that the subject was performing at a given time step and the observable variable is the vector of sensor readings. hmm model mainly works on two basic principles as follows: the observable variable at time t, namely x t , depends only on the hidden variable y t . the hidden variable at time t, namely y t , depends only on the previous hidden variable y t−1 . learning the parameters of these parameters corresponds to maximizing the joint probability p(x, y) between the sensor data and activities in the training data. the joint probability therefore factorizes as follows: the main aim of this model is to determine the best hidden state sequence from the observed output sequence that maximizes p(x, y). we validate our method on three public datasets whose information is summarized in hapt datasets provide a large extracted features extracted by prepossessing the raw signals generated from sensors. these algorithms are tested under matlab environment and the wsvm algorithm is tested with implementation libsvm [25] using gaussian kernel is used for all the datasets. each training dataset is normalized before classification within a range of [−1, 1]. we optimized the svm hyper-parameters (r, c) for all training sets in the range [0.1, 0.2, 0.5, 1] and {0.1, 1, 5, 10, 100}, respectively, to maximize the error rate of five fold-cross validation technique. the optimal parameters r opt = 0.9, 0.9, and 0.8 are found to be optimal the training dataset of har, hapt, and wisdm, respectively. we show in the table 2 that the fusion of principal component features with wsvm-hmm makes the model more robust, achieving better performance. one also notices for har dataset that the multi-class wsvm method improves the classification results over mc-svm, mc-hf-svm and hmm classifiers used alone. on the other hand, the results also show that wsvm outperforms hmm for recognizing activities for all datasets except for the hapt dataset. in terms of reducing the datasets, the feature reduction identifies the most relevant features for the learning process. we notice that pca features can improve the discrimination between different activities than the original features. for wisdm the performances of activity recognition are low than har and hapt datasets with 561 features. this is explained by the number of features (6) for wisdm is not sufficient when using pca algorithm. another reason to the lowest accuracy in wisdm dataset is attributed to the use only the accelerometer sensor comparatively to the har and hapt that use the both accelerometer and gyroscope sensors. to get a detailed knowledge of the performances on each class corresponding to current activity for the har dataset with six different activities. we calculate the confusion matrix of the proposed method in table 3 . from these tables, we see that the best performances were obtained for the proposed method for all classes, in particular for the static activities (sitting and standing). in the table 3 , 96.2% of 'w. upstairs' activity instances are correctly recognized, while 2.4% goes into 'w. downstairs' and 1.2% are confused with 'walking' activity. the similar classes such as 'walking', 'w. upstairs', and 'w. downstairs' show similar trend of sharing errors among each other. the reason is the similar status of smartphone when the user does these dynamic activities. we notice that the static activities share errors among each other. 12.2% of 'standing' activity instances are confused with 'sitting' activity and 7.4% of 'sitting' activity instances are confused with 'standing' activity. intuitively, this can be explained by the fact that the patterns in the acceleration data between these activities are somewhat similar. experimental results of the hybrid model presented demonstrate how it can be effectively employed for activity recognition of static and dynamic activities. it obtains a significant performance. specifically, we show how the hybrid system obtained by using the wsvm label output a new feature added to the reduced data for training and testing hmm outperforms other well known supervised pattern recognition approaches. we consider that wsvm approach has great potential to deal the imbalance class in this human activity recognition problem. however, it must be noticed that hybridizing these schemes implies a more complex system. fortunately, the training phase in a deployed activity recognizer is usually done offline, so we do not consider such growth of complexity a real problem in our domain. impact of smartphone's on society improving human activity recognition in smart homes healthcare in the pocket: mapping the space of mobile-phone health interventions an automatic data mining method to detect abnormal human behaviour using physical activity measurements a survey of online activity recognition using mobile phones human activity recognition and prediction smart phone based data mining for human activity recognition human activity recognition on smartphones using a multiclass hardware-friendly support vector machine sarm: salah activities recognition model based on smartphone human activities recognition in android smartphone using support vector machine subject-independent human activity recognition using smartphone accelerometer with cloud support towards physical activity recognition using smartphone sensors soft margin svm modeling for handling imbalanced human activity datasets in multiple homes pattern recognition of human activity based on smartphone data sensors using svm multiclass hmm machine learning and inference for activities of daily living recognition principal component analysis support vector machines: training and applications controlling the sensitivity of support vector machines weighted support vector machine for classification with uneven training class sizes the joint use of sequence features combination and modified weighted svm for improving daily activity recognition hmm machine learning and inference for activities of daily living recognition a practical guide to support vector classification activity recognition using cell phone accelerometers ), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the creative commons license and indicate if changes were made. the images or other third party material in this chapter are included in the chapter's creative commons license, unless indicated otherwise in a credit line to the material. if material is not included in the chapter's creative commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use key: cord-258239-7xyqlz0u authors: gärtner, fabian; knippschild, uwe; burster, timo title: application of an activity-based probe to determine proteolytic activity of cell surface cathepsin g by mass cytometry data acquisition date: 2020-10-19 journal: acs omega doi: 10.1021/acsomega.0c04092 sha: doc_id: 258239 cord_uid: 7xyqlz0u [image: see text] during an immune response, cathepsin g (catg) takes on the role of adaptive and innate immunity and the outcome depends on the localization of catg. soluble, cell surface-bound, or intracellular catg is also responsible for pathophysiology conditions. we applied the activity-based probe mars116-bt to mass cytometry by time-of-flight to analyze catg activity on the cell surface of immune cells. the phosphonate warhead of mars116-bt binds covalently to the serine amino acid residue s195 of the catalytic center and thereby catg activity can be detected. this method contributes to observing the activation or inhibition status of cells during pathogenesis of diseases and enables accurate data acquisition from complex biological samples with a vast panel of cell subset markers in a single-cell resolution. hypertension, cardiac diseases, and diabetes are some of the consequences of cardiac dysfunction. elevated blood pressure is the result of vasoconstriction, which is triggered by angiotensin ii binding to the type 1 angiotensin receptor. additionally, angiotensin ii enhances inflammation and fibrosis. 1 how is angiotensin ii generated? angiotensinogen is cleaved by renin to angiotensin i and is further proteolytically digested by the angiotensin-converting enzyme (ace) to angiotensin ii. importantly, neutrophil-derived cathepsin g (catg), which can be soluble or bound to the cell surface of neutrophils, and mast cell-derived chymase are also able to convert angiotensin i to angiotensin ii. 2−5 ace2 processes angiotensin ii to angiotensin 1−7, which is, on the one hand, valuable in lowering blood pressure by vasodilation and provokes the kidneys to excrete sodium and water. on the other hand, it also exhibits an anti-inflammatory capacity. downregulation of ace2-expressing cells can cause activation of the renin angiotensin system, which regulates vascular and cardiac physiology and is central to common pathologic conditions such as hypertension and heart failure. 6, 7 neutrophils can be identified by a set of cell surface markers, among them are cd11b, cd16, and cd66b, which are reliably expressed across the neutrophilic population. in addition, these cell surface markers are independent from the location or activation status of neutrophils. 8 activated neutrophils, under conditions of both inflammation and homeostasis, express cell surface markers, such as cd62l (l-selectin), cd54 (intracellular adhesion molecule 1, icam-1), cd32 (fcγrii), and cd88 (c5a receptor). 9 activation of neutrophils can also be artificially induced using phorbol myristate acetate. 10 catg, a serine protease, together with neutrophil elastase, proteinase 3, and neutrophil serine protease 4 is secreted by activated neutrophils. cell surface catg on neutrophils is still proteolytically active, 11 although natural serine protease inhibitors, including α 1 -antitrypsin, are present at the site of inflammation but cannot inhibit cell surface catg. first, neutrophils release matrix metalloproteases in order to proteolytically inactivate α 1 -antitrypsin, 12 and second, the bulky natural serine protease inhibitor, α 1 -proteinase inhibitor might not be able to reach the catalytic center of cell surfacebound catg by steric hindrance. 11 catg possesses a catalytic triad, as with other proteases, containing histidine, aspartate, and serine amino acids within the active center (h57, d102, and s195). the active site cleft is perpendicularly oriented to the two β barrels where the hydroxyl group of s195 nucleophilically attacks the carbonyl carbon of the scissile peptide bond. 13, 14 human catg shows trypsin, chymotrypsin, metase, and lyase activity. 15, 16 additionally, it was demonstrated by performing protease profiling that catg has a preference at the p1 position holding an asparagine (n), at p2 proline (p), and at p3 glutamic acid (e) and at the alternate subsite p1′ isoleucine (i), alanine (a), and serine (s) as well as at the p2′ negatively charged amino acids (aspartic acid, d, and glutamic acid, e). 17, 18 in our previous work, we analyzed distinct cell populations in the peripheral blood of healthy donors for their cell surface catg activity by applying the activity-based probe mars116-bt in a flow cytometry approach. this method circumvents cell separation from a mixture of cells found in blood or tissue to detect catg activity by a western blot-based assay or by enzymatic kinetics. 19 mass cytometry by time-of-flight (cytof) is the next generation of flow cytometry to simultaneously analyze a complex panel of cell markers, which is not possible with the classical fluorescence flow cytometer. hence, a multiplexed profiling of up to 100 surface markers as well as intracellular signaling proteins is possible. 20, 21 until now, the detection of cell markers, including proteases, via application of cytof has been limited to analysis at the protein level. to this end, we established an approach to determine the proteolytic activity of catg on the cell surface of neutrophils, nk cells, b cells, and t cells in peripheral blood mononuclear cells (pbmcs) by combining the activity-based probe mars116-bt and the antibiotin-150 nd antibody with cytof analysis. the technique outlined here demonstrates that catg can be detected on cd16 + cd66b + neutrophils and nk cells using the cytof methodology. therefore, mars116-bt-anti-biotin-150 nd antibodies are useful to profile a vast panel of different cell subsets in order to evaluate catalytically active catg, its regulation, or inhibition on the cell surface. 2.1. detection of catg activity on the cell surface of neutrophils by cytof. activity-based probes are applied to detect cysteine and serine protease activity. 22−24 mars116-bt contains a biotin, spacer, amino acid sequence for specificity, and a warhead. mars116-bt, with an incorporated electrophilic phosphonic active site-directed warhead, binds covalently to the oxygen atom of s195 within the catalytic center of catg. 25 pbmcs were incubated with mars116-bt with a group of specific antibodies that were conjugated with different isotopes ( 147 sm-cd20, 154 sm-cd45, 155 gd-cd56, 160 gd-cd14, 162 dy-cd66b, 165 ho-cd16, 168 er-cd8, 170 er-cd3, 173 yb-hla-dr, and 174 yb-cd4) to determine immune cells and their respective subsets. furthermore, the groups were treated with different inhibitors to distinguish specificity. one control group was incubated without an inhibitor, two groups were preincubated with the reversible catg inhibitor (catginh.) in a final concentration of 12.5 or 50 μm, and one group was treated with the irreversible catg inhibitor suc-val-pro-phe p (oph) 2 (sucvpf) 26, 27 in a final concentration of 50 μm before adding mars116-bt. subsequently, antibiotin-150 nd antibodies were added to the samples and catg activity was monitored by cytof combined with the respective software (summarized in figure 1 ). after data acquisition, the fcs files were normalized based on the calibration beads (eq four element calibration beads) using the built-in normalizer of the helios. the beads were gated out of the analysis and the cells were gated for dna double-positive events ( 191 ir and 193 ir) to exclude doublets for accurate single-cell identification. cd45 was used as a marker for pbmcs. a further gating procedure was carried out to differentiate between cd4 + t cells (cd3 + , cd4 + , cd8 − , and cd20 − ), cd8 + t cells (cd3 + , cd4 − , cd8 + , and cd20 − ), b cells (cd20 + and hla-dr + ), monocytes (cd3 − , cd14 var , cd16 var , cd20 − , cd56 − , and hla-dr + ), nk cells (cd3 − , cd14 − , cd16 var , cd20 − , and cd56 var ), eosinophils (cd3 − , cd16 − , cd20 − , cd56 − , and cd66b + ), and neutrophils (cd3 − , cd16 + , cd20 − , cd56 − , and cd66b + ). nk cells were further subcategorized by gating for the cell surface expression of cd16 and cd56 based on previously established gating procedures of regular flow cytometry. 28 in the next step, the 150 nd channel was adjusted for catg activity selecting cd4 + t cells, cd8 + t cells, b cells, monocytes, nk cells, and their subsets, as well as eosinophils and neutrophils. in contrast to b cells or t cells, eosinophils and neutrophils showed a robust level of proteolytically active catg (figure 2 and supporting information s1). additionally, the nk cell subset cd16 + cd56 − (no. 5) harbors detectable catg activity, as demonstrated in figure 3 . the specificity of cell surface-active catg was determined by signal reduction when samples were preincubated with catg inhibitors (catginh. and sucvpf). thus, the methodology of cytof can be used for deep profiling of neutrophils, eosinophils, and nk cells as well as for http://pubs.acs.org/journal/acsodf article detection of proteolytically active catg by applying mars116-bt. furthermore, cytof is a valid method to detect not only the presence of specific antigens but also their proteolytic activity. the next-generation flow cytometry cytof setup in combination with mars116-bt-anti-biotin-150 nd antibodies allows us to analyze and gate distinct cell subsets and simultaneously determine the proteolytic activity of catg. this approach can be used to monitor neutrophils for the efficacy of inhibitors to arrest catg activity as well as disease progression where catg activity is upregulated. furthermore, mars116-bt-anti-biotin-150 nd antibodies can be added to a vast panel of activation markers in cytof analysis to characterize immune cells during inflammation, inducing a pathologic effect, in homeostasis, or when stimulated with different substances. additionally, different activity-based probes can be applied to cytof to detect further serine proteases or even cysteine proteases in a single-cell approach. in previous work, we detected catg activity in both nk cell subsets, cd3 − cd16 − cd56 dim and cd3 − cd16 dim cd56 − nk cells, 19 by common flow cytometry. compared to the cytof analysis demonstrated here, catg activity detection was limited to cd16 + cd56 -nk cells. this gives rise to speculation that a low amount of catg activity cannot be detected by cytof and is certainly a limitation of this technique. the use of mars116-bt-anti-biotin-150 nd antibodies for characterizing the catalytic activity of catg is not only practical for immune cells from the blood. we also suggest sputum from patients or tissue from animal models because application of the mars116-bt-anti-biotin-150 nd antibodies is not restricted to cells from humans. furthermore, treatment with protease inhibitors to regulate imbalanced proteolytic activity in several diseases is indicated. with respect to serine protease inhibitors, boswellic acids (bas) inhibit the catalytic activity of catg. 29 previously, it has been shown that ba interferes with the chemoinvasion of neutrophils, suppresses inflammation, and possesses potential cardioprotective properties. 29−31 inhibition of catg by ba could be monitored by mars116-bt-anti3.2. application of mars116-bt in cytof. pbmcs from one donor were thawed, washed twice with pbs, and used in a final concentration of 1.5 × 10 6 pbmcs/staining for both titration of antibodies and the experiments. the experiment was split into four groups, one control group treated with pbs, two groups that were preincubated with the reversible catg inhibitor (catginh., calbiochem, merck chemicals gmbh, schwalbach, germany, cat. no.: 219372) at two concentrations, 12.5 and 50 μm, and one group treated with 50 μm of the irreversible catg inhibitor, suc-val-pro-phe p (oph) 2 (sucvpf). 26 preincubation was performed for 15 min at room temperature (rt). afterward, cells were washed with pbs, centrifuged (300g for 8 min), and incubated with mars116-bt, which was synthesized as described previously, 25 in a final concentration of 2 μm for 30 min at rt, followed by three wash steps in pbs, and centrifugation at 300g for 8 min. cells were stained with the following mixture of antibodies, as depicted in table 1, in rpmi supplemented with 10% dmso until the day of acquisition. the samples were thawed followed by one washing step in pbs with 10% fcs, and three washing steps with milliq water (600g, 8 min). thereafter, cells were acquired at 300 events/second with a helios cytof system (fluidigm, markham, canada). calibration beads (eq four element calibration beads, fluidigm #201078, markham, canada) were used at a concentration of 10%. 3.3. data analysis. the data were analyzed using manual gating with flowjo x (flowjov10.6.2, flowjo llc, ashland, or, usa) as well as automated clustering approaches using spade (cytobank 7.3.0., implemented version, santa clara, ca, usa). statistical analysis was performed with the commercially available software, graphpad prism 6, inc., san diego, ca, usa. data were normalized to the specific untreated control population and expressed as normalized intensity in percent. the ± standard error of the mean (s.e.m.) is shown. significant differences were considered at p < 0.05 (*), p < 0.01 (**), p < 0.001 (***), or p < 0.0001 (****). 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and cathepsin g as therapeutic targets in human diseases the 1.8 a crystal structure of human cathepsin g in complex with suc-val-pro-phep-(oph)2: a janusfaced proteinase with two opposite specificities how immune peptidases change specificity: cathepsin g gained tryptic function but lost efficiency during primate evolution new chromogenic substrates of human neutrophil cathepsin g containing non-natural aromatic amino acid residues in position p(1) selected by combinatorial chemistry methods extended cleavage specificity of human neutrophil cathepsin g: a low activity protease with dual chymase and tryptase-type specificities charge-synchronized" proteome-derived peptide libraries cell surface cathepsin g activity differs between human natural killer cell subsets application of mass cytometry (cytof) for functional and phenotypic analysis of natural killer cells coumarin as a structural component of substrates and probes for serine and cysteine proteases activity-based profiling of proteases recent advances in activity-based protein profiling of proteases application of a novel highly sensitive activity-based probe for detection of cathepsin g irreversible inhibition of serine proteases by peptide derivatives of (alpha-aminoalkyl)phosphonate diphenyl esters application of specific cell permeable cathepsin g inhibitors resulted in reduced antigen processing in primary dendritic cells cd56bright natural killer (nk) cells: an important nk cell subset identification of human cathepsin g as a functional target of boswellic acids from the anti-inflammatory remedy frankincense boswellia serrata: an overall assessment of in vitro, preclinical, pharmacokinetic and clinical data anti-inflammatory and anti-cancer activities of frankincense: targets, treatments and toxicities key: cord-016089-h122of8q authors: li, haixia; lu, chunbo title: lonicera japonica thunb 金银花 (jinyinhua, honey suckle) date: 2015-02-19 journal: dietary chinese herbs doi: 10.1007/978-3-211-99448-1_78 sha: doc_id: 16089 cord_uid: h122of8q jinyinhua, a sprawling and twining lianas in the family of caprifoliaceae, is a popular chinese herbal medicine used for the treatment of inflammatory diseases and as a well-known dietary supplement that has been used for many centuries. material can be obtained and marketed. during drying procedures, do not direcctly expose the flowers to strong sunlight because it will darken the flowers. other processing methods are further performed for some specific medicinal purposes, such as fried jinyinhua and charcoaled jinyinhua etc. in recent years, sulfurfumigation has been used to replace natural drying processing for efficiency and pest control [4] . organic acids, flavonoids and volatile oil are the three major classes of bioactive compounds found in jinyinhua [1] . in addition, shuangkangsu (shown in fig. 78 .2 (8) ), which has the marked anti-viral activity against influenza b virus, influenza a3 virus and respiratory syncytial virus, is an important chemical constituent with a novel skeleton structure of cyclic peroxide. it was found in 2008. organic acids are the main and effective components of l. japonica. chlorogenic acid (1), isochlorogenic acid (2), neochlorogenic acid (3) , and caffeic acid (4) (shown in fig. 78 .2) are representative compounds. among them, chlorogenic acid is received considerable attention for its part in the human diet with potential biological effects [5] , and is used as a standard compound for evaluation of the quality of jinyinhua and related pharmaceutical or natural health product containing the herb. according to the chinese pharmacopoeia, its content must be not less than because flavonids have a wide spectrum of biological activities, especially with antioxidative and anti-inflammatory properties, they play a part in the qualitative and quantitative analysis of jinyinhua. luteoloside (5) was added in chinese pharmacopoeia with chlorogenic acid to control the quality of medical material by hplc method. the content of luteoloside in the jinyinhua should be not less than 0.05 %. besides luteoloside, other flavonoids, such as luteolin (6) and lonicerin (7) (shown in fig. 78 .2), have exerted anti-inflammatory activity [6] . as one of the important compositions, volatile oil is significant in both the wide activity and utilization of jinyinhua. a total of about ninety compounds of volatile oil were identified, the main compound being linalool [7] . due to the differences in harvesting time and processing technics, the contents and components of volatile oil are different. existing research showed that the complete white and silver flower period are the preferable harvest times for volatile oil, which match with the best time to harvest for chlorogenic acid. low temperature and no-lighting were in favor of the volatile oil in the dry and extract processes [1] . as described previously, jinyinhua is one of widely used herbs in tcm, especially for almost all infectious diseases, due to its antimicrobial and anti-inflammatory activities. the two activities act synergistically to accelerate wound repair [8] . moreover, the modern pharmacological studies showed that jinyinhua and its active principles also possess the wide pharmacological actions, such as antiendotoxin, antipyretic, antihyperlipidemic, antithrombotic, anti-oxidative and anti-carcinogenic activities, and hepatoprotective etc. [1] . in addition, anti-lipase, insecticidal and acaricidal activities were also found in the crude extract of jinyinhua. in recent years new bioactivities, such as the potent anti-parkinsonism activity [9] and protecting neuronal cells against glutamate excitotoxicity via antioxidative activity [10] , inhibition of the allergic contact dermatitis [11] , and a possible use for antidiabetes, have been discovered and suggested to be in the compounds isolated from jinyinhua due to its potent inhibitor action for maltase [12] . researchers thought most of these effects may be related to the active compositions of volatile oil, chlorogenic acid, and flavones. chlorogenic acid and luteoloside, officially used as the indicator compound to characterize the quality of this herb and its related preparations, were shown to have beneficial effects in the aspects of anti-oxidation and antitumor [1, 13] . moreover, chlorogenic acid showed the antibacterial, antiviral, anti-inflammatory, hypoglycemic activities, and allergy-preventive properties [1, 14] . meanwhile, luteolin, another major flavonoid in jinyinhua, and volatile oil also showed significant anti-inflammatory activity. luteolin has significant bioactivities in the aspects of antifibrotic and anti-5-lipoxygenase activities [6, 15] . taken together, most of these activities matched to traditional usage. jinyinhua with heat-clearing and detoxifying effect has been called little fairyhood of herb store. in tcm clinical practice, jinyinhua is usually used to treat various infectious diseases. as the most famous herb of anti-inflammatory, it is constantly used for upper respiratory tract infections. 1500 years ago, jinyinhua had been used for the treatment of exopathogenic wind-heat, epidemic febrile diseases, carbuncles, sores, furuncles and infection diseases. also, it has also been made in preparations to treat chronic enteritis, pneumonia, acute tonsillitis, nephritis, acute mastitis, and leptospirosis in clinic. more than 500 prescriptions containing jinyinhua have been used to treat various diseases [1] . there are hundreds of manufacturers making these two products based on the same formula in china, these two products are two of the best-selling drugs on market. they are mainly used for the treatment of fever, cough, sore throat, acute and chronic tonsillitis, acute and chronic pharyngitis through its function clearing away the heat and toxic material, antibacterial, anti-inflammatory and antiviral effects. yinhuang buccal tablets and shuanghuanglian buccal tablets have the same compositions as oral liquid but are in a different form. the buccal table form is particularly suitable for swelling and pain of the throat caused by acute and chronic tonsillitis, pharyngitis and upper respiratory tract infections. yinhuang injection, shuanghuanglian injection, and compound acetaminophen jinyinhua injection are three common used preparations containing jinyinhua. compound acetaminophen jinyinhua injection is composed of the extract of jinyinhua, baicalin, and acetaminophen. these products have been used clinically for the treatment of upper respiratory tract infections, sore throat, tonsillitis, mumps and pneumonia, and compound acetaminophen jinyinhua injection has also been used to relieve moderate pain, such as arthralgia, headache, and toothache. adverse reactions of these products after intravenous injection were detected so these injections are better to be administered by intramuscular injection. jinyinhua granula prepared by itself is an extract in a convenient form that is used by being mixed with other herbs. recently, jinyinhua, as 'bouvardin', has been used extensively to prevent and treat some serious viral diseases of humans and animals, such as sars corona virus, h1n1 (swine) flu virus [16] . jinyinhua is a well-known dietary supplement due to its valuable bioactivies and because it's easy to obtain since it is planted in many areas as one of ornamental groundcover. it can be used in many ways historically. these include jinyinhua beverage, jinyinhua candy, and jinyinhua soup etc. the following dietary forms can be easily bought at a market or made at home. jinyinhua has been used to make healthy beverage through various technologies, such as jinyinhua tea, jinyinhua dew, jinyinhua nutritive dew, jinyinhua nutritive beverage, and jinyinhua yogurt etc. these beverages are employed to improve the body and prevent illnesses in china [1] . jinyinhua tea has a variety of practices, such as jinyinhua by itself, combined with tea, combined with honey, or combined with other herbs. all of them are popular ways to use jinyinhua. they are typically drunk in the hot season for clearing heat, detoxicating and strengthening the body's response against disease by improving the activity of the immune system. some examples are: jinyinhua dew composed of the distilled liquid of jinyinhua and water. jinyinhua tea can be drunk after boiling water of 150 ml to soak jinyinhua (5 g) and green tea (3 g) for 5-10 min. according to further needs, jinyinhua can be combined with other herbs with bioactivities for enhancing its effect. jinyinhua shanzha tea composed of jinyinhua (10 g), juhua (flowers of chrysanthemum morifolium, 10 g), and shanzha (fruits of crataegus pinnatifida, 10 g) for headache, fever and thirst caused by hotness. jinyinhua bohe tea composed of jinyinhua (15 g), bohe (aerial parts of mentha haplocalyx, 5 g), and gouqi (fruits of lycium chinense or l. barbarum, 15 g). jinyinhua itself or combined with different herbs can be used to make herbal wine for various specific needs of functions. some examples are: the extracting solution of jinyinhua (alcohol content 55 %) is added before fermentation, the following process is the same as used to brew wine [17] ; jinyinhua (45-55 g), gancao (roots and rhizomes of glycyrrhiza uralensis, g. inflate, or g. glabra, 5-10 g), gouqi (fruits of lycium chinense or l. barbarum, 25-30 g) and baizhi (roots of angelica dahurica, 5-10 g) are soaked in 500 ml wine of alcohol content between 55-60 % for more than 25-50 days, then it can be adjusted into different contents of alcohol according to needs. jinyinhua, the material which can be used as medicine and food, is often made into candy together with other herbs. some examples are: jinyinhua qingguo pipa candy composed of jinyinhua, qingguo (chinese olives, fruits of canarium album), pipa (fruits of eriobotrya japonica), jiegeng (roots of platycodon grandiflorum) and baimaogen (rhizomes of imperata cylindrica); jinyinhua cool candy is composed of jinyinhua, qingguo, luohanguo (fruits of siraitia grosvenorii), pangdahai (seeds of sterculia lychnophora) and bohe (aerial parts of mentha haplocalyx); jinyinhua juhua candy is composed of jinyinhua, bohe and juhua (flowers of chrysanthemum morifolium). white granulated sugar and liquid glucose are usually added to adjust the taste. you can buy the candy in the supermarket for the purpose of moistering and clearing the throat. jinyinhua can be used to make soups or porridge with rice, or mung bean etc. a typical way is to boil 100 g mung bean and a piece of ginger in 1 liter of water before adding 30 g jinyinhua, then continuously boil until the mung bean cracks and are fully cooked. other ingredients, such as wax gourd, lily bulbs, lotus root, almond, pears, and ham etc., can be boiled together with jinyinhua. beautiful white and yellow color, nutrient, and health-maintaining effect of jinyinhua can be employed simultaneously. the taste of jinyinhua-contained foods can be adjusted by adding honey, white granulated sugar or licorice. in addition, the oil and extracts from jinyinhua may be a potential source of preservatives for the food industries [1] . in qing dynasty of china, about 375 year ago, jinyinhua was used to moisturize the skin and for rejuvenation. recently, the extract of jinyinhua, as natural source of bioactive compounds, have been applied in cosmetics, extensively to exert its marked antibacterial and antisepticize activities, such as jinyinhua facial mask, jinyinhua facial cleanser, and jinyinhua shower gel. it could be made into toothpaste which could have the effects of preventing and treating the oral cavity's diseases [1] . in addition, the volatile oil isolated from jinyinhua would cover the smell from cigarettes. and chlorogenic acid and its analogues, which are beneficial to health, are rich in jinyinhua. it can be added into cigarettes to serve a useful role in improving the quality of cigarettes and preventing disease. jinyinhua is mostly used in combination with other herbs with heat-clearing and detoxifying effect, such as huangqin (roots of scutellaria baicalensis), lianqiao (fruits of forsythia suspensa) etc. more than 12 preparations, in which jinyinhua was the main and active compositions, were listed in chinese pharmacopoeia (2010 edition) and used to cure fever, cough and pharyngalgia and the swell of throat, constipation, conjunctival congestion, etc. except the aforementioned preparations: injection, oral solution, granular, or suppository of yinhuang, shuanghuanglian and yinzhihuang, simiaoyongan decoction, yinqiao jiedu tablets, and xiaoyin tablets etc. are the most commonly used preparations. there are large numbers of clinical related reports or observational studies published on the effects of jinyinhua and its related preparations for various diseases. clinical report showed shuanghuanglian oral solution's effect of antipyretic on wind and warm syndrome was 100 % within 72 h in 48 cases [18] ; and the preparation could effectively relief the cold symptom of cough, headache, nasal discharge, sore throat. it could also stop the cheek swelling of child with epidemic parotitis [19] . yinzhihuang oral solution, which is composed of four herbal components: jinyinhua, yinchen (aerial parts of artemisiae scopariae or a. capillaris), huangqin (roots of scutellaria baicalensis), and zhizi (fruits of gardenia jasminoides), may inhibit further increase in bilirubin levels, and reduced the phototherapy requirement in 1177 cases of neonatal indirect hyperbilirubinemia in term newborn infants [20] . simiao yongan (trade name: mailuoning) is used in treating ischemic cardiovascular and cerebrovascular diseases for many years in clinical and comprises jinyinhua, xuanshen (roots of scrophularia ningpoensis), danggui (roots of angelicae sinensis) and gancao (roots and rhizomes of glycyrrhiza uralensis, g. inflate or g. glabra), clinical studies have shown that it can inhibit the inflammatory response and antagonize the blood clotting process [21] . because jinyinhua is an edible herb and commonly used as raw material in health food, clinical reports on the toxicity or side effects were done to determine its safety at least 10 years ago. the extract of jinyinhua was found to be fairly nontoxic when oral taken by rats or mice. the detail was as follow. acute toxicity test showed its ld 50 was more than 15 g/kg body weight on mice orally. according to the classification standard of chemicals acute toxicity, it belongs to non-toxic level. micronucleus test of bone marrow cells up to 7.5 g/kg in mice orally and ames test/ mammals microsomal enzyme test showed it was safe without mutagenesis. meanwhile, sperm abnormalities and antifertility effect were undetected on male mice and sd female rats, respectively [22] . in addition, jinyinhua combined with the dried zhimu (rhizomes of anemarrhena asphodeloides) showed no signs of acute or chronic toxicity in terms of general behavior, gross appearance of the internal organs, blood chemistry, or mortality in male or female rats when orally administered a single dose of 5,000 mg/kg in acute toxicity test or 500, 1000 or 2,000 mg/kg daily for 13 weeks in chronic toxicity test. they didn't cause significant gastric mucosal damage after single or repeated doses, instead appearing to protect the mucosa from diclofenac-induced gastric damage [23] . to sum up, as a material of being used as medicine and food, jinyinhua is definitely a safe herbal medicine, and often used for the treatment of infectious diseases and health maintaining purpose. it can also be used for relieving cold and cleaning away poison. but the close attention must be paid when deciding to use this herb for cold because it is obvious that the cold treated by jinyinhua refers only to a pyretic cold rather than a frigid cold, and this herb is inapplicable for the hypofunction of person's constitute with cold manifestation consideration of its strong clearing heat activity. lonicera japonica thunb.: ethnopharmacology, phytochemistry and pharmacology of an important traditional chinese medicine combination of normal light and fluorescence microscopy for authentication of five lonicera species flower buds pharmacopoeia of people's republic of china profiling and characterization of volatile components from non-fumigated and sulfur-fumigated flos lonicerae japonicae using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry coupled with chemical group separation an outlook on chlorogenic acids-occurrence, chemistry, technology, and biological activities luteolin isolated from the flowers of lonicera japonica suppresses inflammatory mediator release by blocking nf-kappab and mapks activation pathways in hmc-1 cells chemical composition of the essential oils from the flower, leaf and stem of lonicera japonica wound repair and anti-inflammatory potential of lonicera japonica in excision wound-induced rats lonicera japonica thunb. protects 6-hydroxydopamine-induced neurotoxicity by inhibiting activation of mapks, pi3 k/akt, and nf-kappab in sh-sy5y cells neuroprotective activity of the methanolic extract of lonicera japonica in glutamate-injured primary rat cortical cells characterization and anti-allergic effect of a polysaccharide from the flower buds of lonicera japonica α-glucosidase inhibitory activity by the flower buds of lonicera japonica thunb hplc-esi-ms/ms analysis and pharmacokinetics of luteoloside, a potential anticarcinogenic component isolated from lonicera japonica, in beagle dogs allergy-preventive effects of chlorogenic acid and iridoid derivatives from flower buds of lonicera japonica luteolin ameliorates experimental lung fibrosis both in vivo and in vitro: implications for therapy of lung fibrosis research and comprehensive utilization of honeysuckle studies on health food of honeysuckle research on antipyretic project of tcm emergency care for exogenous fever with analysis of 906 progress in clinical application of shuanghuanglian oral liqui clinical research collaborative group of yinzhihuang oral solution (2011) a multicenter randomized controlled study on the efficacy and safety of yinzhihuang oral solution for the treatment of neonatal indirect hyperbilirubinemia in term newborn infants effect of si-miao-yong-an on the stability of atherosclerotic plaque in a diet-induced rabbit model the toxicological assessment of lonicera japonica on food safety gastroprotective and safety effects of win-34b, a novel treatment for osteoarthritis, compared to nsaids key: cord-022779-himray6q authors: nan title: abstracts of oral presentations date: 2005-06-10 journal: biopolymers doi: 10.1002/bip.20321 sha: doc_id: 22779 cord_uid: himray6q nan s. tchertchian, f. oplinger, m. paolini, s. manganiello, s. raimondi, b. depresle, n. dafflon, h. gaertner, and p. botti geneprot inc., geneva branch, 2, pré de-la-fontaine, 1217 meyrin, switzerland the last decade has provided extensive demonstration of the key role played by native chemical ligation (ncl) for the preparation of small and medium size proteins [1] . yet the requirement for cysteine at the site of ligation in standard ncl has limited its flexibility. recently, different types of auxiliary groups [2, 3] have been developed to extend the application of ncl to other ligation sites. however, the generally slower ligation rates especially with large fragments and the additional step required to cleave the auxiliary post-ligation have reduced their utility. here we present a novel strategy to synthesize proteins through a chemical ligation using unprotected peptide segments. our scheme does not make use of auxiliary groups [2, 3] , instead originally exploits the features of some side chain removable functionalities. ligation rates are high, comparable to ncl and the residues available for ligation are more frequent than cysteine. furthermore the whole process is "one pot" and at the end a native polypeptide is obtained directly in the ligation mixture. the total chemical syntheses of c5a (1-74) using both ncl and our method will be presented and compared. [ during the biosynthesis of glycopeptide antibiotics of the vancomycin family, several oxidative phenol coupling reactions take place. the enzymes catalyzing these reactions are of interest from structural and mechanistic viewpoints. in this work [1, 2] , it is shown that the oxygenase oxyb from the vancomycin producer only catalyzes a phenol coupling reaction when the putative peptide substrate is linked as a thioester to a peptide carrier domain (pcd) derived from the nonribosomal peptide synthetase. an efficient access is described to representative free linear peptide substrates, which makes use of alloc-solid phase peptide chemistry, but largely avoids the use of amino acid side chain protecting groups. in this way, the target linear peptides can be released from the resin under very mild conditions, and then be activated as thioesters, prior to loading onto the pcd. [ we have recently discovered a new nonenzymatically-formed product from n-(3-oxododecanoyl)-l-homoserine lactone. interestingly, both the n-acylhomoserine and its novel tetramic acid degradation product 1 are potent antibacterial agents. bactericidal activity was observed against all tested gram-positive bacterial strains, while no toxicity was seen against gram-negative bacteria. we propose that p. aeruginosa utilizes this tetramic acid as an interference strategy to preclude encroachment by competing bacteria. additionally, we have discovered that this tetramic acid binds iron with comparable affinity to known bacterial siderophores, possibly providing an unrecognized mechanism for iron solubilization. using short portions (7-11 amino acid) rich in positively charged residues from either human lactoferricin or the marcks protein as templates, a panel of 70 peptides each possessing a specific chemical structure was synthesized. these included amino acid omissions, substitutions, and insertions in the aim to modify the peptides overall charge, hydrophobic core, and/or amphipathicity. the peptides antimicrobial activities against a large panel of bacteria were assessed using both conventional tests (mic, mbc) and non-conventional assays (mic quantified by an automated turbidimetry-based system and mbc measured on resting cells suspended in low-ionic strength medium-"survival assay"). furthermore, the membrane permeabilizing activity of the peptides on strains of several gram negative bacterial species was quantitated by measuring their ability both to decrease the mic of novobiocine and to promote the uptake of the hydrophobic fluorescent probe npn. while the mic determined by turbidimetry or by the conventional method did not significantly differ, bactericidal activity of the peptides measured by the survival assay was 1 to 2 orders of magnitude higher than that measured by the conventional mbc test. on the other hand, the two assays used to measure the permeabilizing activity of the peptides rendered similar results. interestingly, the most potent permeabilizers did not correspond with the peptides exhibiting the highest bactericidal activity thus indicating that these two activities have different structural bases. protein farnesyl transferase (pftase) catalyzes the attachment of farnesyl diphosphate (fpp) to proteins that contain a caax-box sequence at their c-termini [1] . several analogues of fpp that incorporate azide functional groups have been synthesized and shown to be incorporated into peptides using pftase as a catalyst. in particular, it has been shown that the prenyl azide moiety from 1 or related analogues can be transferred to the peptide substrate, n-dansyl-gcvia to yield the corresponding thioether-linked products. the resulting azide-containing peptides have been derivatized with a triphenylphosphine-based reagent to generate o -alkyl imidate-linked products rather than the amide-linked material expected via a staudinger reaction [2] . since caax-box sequences can be appended to the c-termini of many different proteins, these analogues provide a simple and general method for incorporating orthogonal azides into proteins at unique sites. subsequent functionalization of such azide groups via staudinger or "click" chemistry should provide a convenient method for linking proteins with a diverse array of probes, biomolecules, surfaces and other materials under mild conditions. chemoselective glycosylation, acylation, and alkylation of completely unprotected peptides can be accomplished by incorporating n-alkylaminooxy amino acids into the peptide sequence. the n-alkylaminooxy side chains react selectively with reducing sugars, activated alkyl halides, and various acylating agents in mildly-acidic aqueous buffers (ph 4) to furnish neoglyco-and neolipopeptides. a key feature of the approach is that a single parent peptide can be quickly reacted with a variety of agents to provide a large number of "post-translationally"modified peptides. the ability to easily synthesize arrays of modified peptides allows comprehensive studies of the effects that glycosylation and lipidation have on peptide structure and function. here we present an overview of the methodology and initial results on its application to studying problems of biological interest. this presentation describes cyclic peptides that fold into well-defined ␤-sheet structures in aqueous solution and can dimerize through ␤-sheet interactions. the cyclic peptides contain the unnatural amino acid hao, which mimics the hydrogen-bonding pattern of one edge of a peptide ␤-strand, and ␦-linked ornithine, which mimics a ␤-turn and provides enhanced water solubility or a linkage point for creating multivalent structures. institute for molecular bioscience, the university of queensland, queensland 4072, australia the human genome project and other major sequencing projects have rapidly provided a vast array of new protein/peptide sequences. in contrast, many other new proteins/peptides are also being uncovered from plant and animal sources whose genomes are yet to be tapped. in the post-genomic era, the physical form of many of these gene-encoded sequences will be vital for biomedical research and drug development. moreover, the advantages of peptide and protein chemical synthesis over recombinant-dna methods are increasingly being used to provide rapid structure-activity information of complex bioactive peptides, small proteins and functional receptor domains. in a program designed to exploit the potential of australian conus species we have isolated, characterised and chemically synthesised a wide range of novel conotoxins. these cysteine rich microproteins have well-defined tertiary structures with considerable rigidity and stability and contain many elements of protein secondary structure. of particular interest are the two disulfide bond containing conotoxins (examples below) which target transporters, ion channels and receptors at nanomolar potencies. in this presentation i will describe some of our research on controlling the shape and potency/selectivity of these microproteins through intramolecular native ligation chemical approaches. it appears that there is considerable scope to control the properties of these native sequences which in some cases may prove useful in the development of these molecules as therapeutic candidates. despite identical amino acid composition, differences in the properties of class a amphipathic helical peptides due to differences on the hydrophobic face results in substantial differences in anti-inflammatory properties. one of these peptides is an apolipoprotein a-i mimetic, d-4f. when given orally to mice and monkeys, d-4f caused the formation of pre-␤ hdl, improved hdl-mediated cholesterol efflux, reduced lipoprotein lipid hydroperoxides, increased paraoxonase activity and converted hdl from pro-inflammatory to anti-inflammatory. in apoe null mice d-4f increased reverse cholesterol transport from macrophages. oral d-4f reduced atherosclerosis in apoe null and ldl receptor null mice. in vitro d-4f caused the formation of pre-␤ hdl, reduced lipoprotein lipid hydroperoxides and converted hdl from pro-inflammatory to anti-inflammatory. physical properties and the ability of various class a amphipathic helical peptides to activate enzyme lcat in vitro did not predict biologic activity in vivo. in contrast, the use of cultured human artery wall cells in evaluating these peptides was more predictive of their efficacy in vivo. thus, anti-inflammatory properties of different class a amphipathic helical peptides depends on subtle differences in the configuration of the hydrophobic face of the peptides. physical-chemical properties provide an explanation for the mechanism of action of the active peptides. peptides to ameliorate atherosclerosis and other inflammatory diseases can be designed using this strategy. inflammatory diseases. this chemokine belongs to the family of cxc chemokines, its response is mediated through binding to seven transmembrane helical g-protein coupled receptors cxcr1 and cxcr2. in order to investigate the relevance of selected protein segments for biological activity we synthesized chemically modified and biologically active analogues of the 77-mer of hil-8 by expressed protein ligation (epl). for ligation naturally occurring cysteine at position 55 was chosen. c-terminal peptides carrying an n-terminal cysteine were synthesized by solid phase peptide synthesis (spps) applying the fmocstrategy and used to introduce modifications. ligation of the recombinantly produced thioester with synthetic peptides yielded in full length hil-8 that finally was correctly folded and stabilised by two disulfide bridges as in the native protein. in addition to fluorescent and photoactivatable analogues, we produced variants that contain a ␤-peptide helix instead of the naturally occurring ␣-helix. thus, for the first time, we received a protein containing a whole ␤-peptide segment and still showing high biological activity. depending on the linker between ␤-sheet and ␤-peptide helix of interleukin 8 we could discriminate between active and inactive proteins suggesting that the overall orientation of the c-terminal segment is highly relevant for the folding of the protein and subsequently for the signalling of interleukin 8. a peptide based on residues 109 -122 of the syrian hamster prion protein (h1) forms ␤-sheet aggregates in solution, which grow to form large fibers. isotope-edited infrared spectroscopy has shown that the initial antiparallel ␤-sheet formed by this peptide is disordered. a slow rearrangement occurs to form a structure in which the hydrophobic core of the strands (residues 112 -122) pack together, resulting in the alignment of residue 117 across the sheet. the kinetics of the realignment have been monitored for h1 and for peptides with mutations at residue 117 (a117i, a117l and a117b where b is aminobutyric acid). h1 and a117i align with non-exponential kinetics. at low concentrations h1 aligns via the repeated detachment and annealing of strands, whereas at higher concentrations a reptation mechanism is observed. a117b aligns instantaneously within the dead-time of our experiments. a117l does not align at residue 117 but some undefined reordering can still be observed as a shift of the 13 c band. these data are the first experimental probes of the types of intersheet rearrangements which are required for the nucleation of fibrous peptide aggregates, and the evidence for strand reptation within the ␤-sheet confirms observations in molecular dynamics simulations. [1, 2] . we have since established the microfluidic peptide chip as a miniaturizing platform. the challenging issues in making peptide chips a practical tool for understanding biology, drug discovery, and diagnostics are quality of synthesis, specificity in reported activities, and ability for quantitative measurements. we will present the results of the work which involves our intensive effort in: • development of the method for monitoring and analyzing quality of peptide chip synthesis • improvement in peptide chip synthesis • development of the methods for quantitative analysis of (a) the specific binding of antibodies/proteins to peptides on chip and (b) kinase enzymatic activities against substrate peptides on chip. our presentation should demonstrate novel applications of peptide chips that can be implemented as routine laboratorial processes. [1] gao, x., pellois, j. p., kim, k., na, y. , gulari, e., and zhou, x. to prototype this approach we developed a protein array consisting of the ras-binding domain of craf-1 (rbd) that was c-terminally modified with a 24mer oligonucleotide and immobilized via hybridization with the complementary oligonucleotide on a wafer [1] . the rbd-dna conjugate was generated by native chemical ligation using a recombinantly produced rbd-thioester and an oligonucleotide carrying a 5'-cystein residue [2] . incubation of the immobilized rbd with ras(gtp), the activated rbd-binding form, retains sufficient amounts of ras on the protein array to allow detection by mass spectrometry with high sensitivity. controls carried out with inactive ras(gdp) did not produce any signal, demonstrating a sufficient selectivity for biotechnological applications. protein microarrays in which proteins are immobilized to a solid surface are ideal reagents for high-throughput experiments that require very small amounts of analyte. such protein microarrays ('protein chips') can be used very efficiently to analyze all kind of protein interactions en masse. the present work describes a general method for the selective attachment of proteins to solid surfaces through its c-termini that can be used for the creation of protein chips. our method is based in the chemoselective reaction between a protein c-terminal ␣-thioester and a modified surface containing n-terminal cys residues. ␣-thioester proteins can be obtained using standard recombinant techniques by using expression vectors containing modified inteins. we also present an efficient solid-phase approach for the rapid synthesis of cys-containing linkers that can be used for the modification of au-and si-based surfaces. this new method was used to immobilize two fluorescent proteins and a functional sh3 domain. a series of glycopeptides based on the leu-enkephalin analogue yt-gfs*-conh 2 led to greatly enhanced stability in vivo and effective penetration of the bbb. transport through the bbb hinges on the biousian nature of the glycopeptides-the glycopeptides have two conflicting conformational manifolds, a h 2 o soluble state, and an amphipathic state at h 2 o-membrane phase boundaries. multiple lines of evidence suggest that the bbb transport mechanism is absorptive endocytosis. mixed /␦-agonists showed antinociceptive potencies greater than morphine, and lacked many of the side effects generally associated with classical -selective opiate analgesics. the biousian design was extended to larger glycopeptides (16 residues) related to ␤-endorphin, which also penetrated the bbb and produced antinociception in mice. plasmon waveguide resonance (pwr) studies showed that the amphipathic helices bound to membrane bilayers with m to low nm k d 's. the presence of diverse endogenous neuropeptide transmitters and neuromodulators in the human brain is potentially applicable to the treatment of a wide range of behavioral disorders. clemencia pinilla, 1 mireia sospedra, 2 yindong zhao, 3 we have recently demonstrated the feasibility of utilizing the ligase activity of inteins for the in vivo backbone cyclization of peptidic chains. this procedure -called siclopps for split intein circular ligation of peptides and proteins-provides a biosynthetic pathway for peptides that are metabolically stable, and can be produced with spatial and temporal control [1] . to screen for bacteriotoxic peptides, a sic-lopps library was introduced into an escherichia coli population, such that each bacterium encodes a different peptide sequence. siclopps library over-expression afforded six distinct bacteriostatic peptides that reduce cell growth. one of these peptides (ln05) also caused cell aggregation. an e. coli genomic library was introduced into cells encoding ln05. co-expression of the genomic library and ln05 peptide rescues growth only in cells expressing genomic fragments able to counteract peptide toxicity. genomic library and ln05 co-expression resulted in enrichment of a single genomic construct, a fragment of the narz gene. narz is part of a nitrate reductase complex and has a role in tuberculosis persistence [2] . ln05 production in mycobacterium smegmatis resulted in a slow-growth phenotype. [1] abel-santos, e., scott, c. p., and benkovic, s. j., methods in the special feature of proteins involved in alzheimer's or prion diseases is their ability to adopt at least two different (meta) stable conformations. thus, amyloid-forming proteins that mainly contain ␣-helical structures in their native conformation must undergo an ␣-helix3␤strand conversion before or during fibril formation. the conformational transition that shifts the equilibrium from the functional to the pathological isoform can happen sporadically. it can also be triggered by mutations in the primary structure, changes of the environmental conditions such as ph, ionic strength, metal ions, protein concentration, oxidative stress, free radicals, action of physiological, or pathological chaperones. alternatively, the introduction of a small quantity of protein polymer may act as a structural template and initiate the disease. therefore, the development of model systems which allow the investigation of the complex folding mechanisms that lead to ␤-sheet aggregation appears to be one of the main challenges in the detailed understanding of the pathways from incubation to mortality. in order to create an ␣-␤ switch system we designed ideal ␣-helical parallel coiled coil peptides, introduced trigger functions by mutations in the primary structure, and studied the consequences that these mutations have on the secondary structure properties of the resulting peptides under certain environmental conditions. based on these results we continued to change the primary structure of the coiled coil system subsequently by mutations in the heptad repeat untill we ended up with soluble ␤-sheet peptides. the most important feature of these new ␤-sheet peptides is that they still follow the characteristic hydrophobic heptad repeat of an ␣-helical coiled coil and that all of the positions which are part of the dimerization domains of the coiled coil remained untouched. thus, these new peptides bear all of the requirements which are necessary for formation of cooperatively interacting helical structures and, furthermore, contain domains for cooperative sheet aggregation as well. the folded structure will now strongly depend on the environment. this peptidic model system allows a systematic study of the subtle influences that environmental conditions may have on protein folding stepwise, which means changing these conditions one after one or in all of the possible combinations that nature applies in vivo. plasmon waveguide resonance (pwr) spectroscopy is a powerful new biophysical method which allows us to examine structural changes, kinetics and thermodynamics of anisotropic biological systems and processes such as proteolipid membranes. this method has probed the mechanisms of g-protein coupled receptor (gpcr) signal transduction, and has obtained new insights into specific signaling pathways of agonists and antagonists with gpcrs. we now have extended these studies to examine the effects of lipid microdomains (rafts) on the binding, signaling and transduction pathways. using a 1:1 mixture of palmitoyloleoylphosphatidyl-choline (popc) and sphingomyelin (sm), we have directly observed the formation of two lipid bilayer microdomains, and the preferred segregation of the delta opioid receptor (hdor) into sm lipid rafts when the agonist ligand was bound, but not for the unoccupied receptor which preferentially incorporated into the popc-rich domain. furthermore, we can demonstrate directly that, g-proteins bind much more strongly to the hdor receptor in the lipid raft (sm-rich) environment than in the fluid non-raft (popc-rich) domain of the lipid bilayer. the implications of these findings for novel design of drugs, and drug screening will be emphasized. † supported by grants from the u.s.p.h.s., national institute of drug abuse and national science foundation. their measurement in high resolution nmr requires partial molecular alignment. for proteins in aqueous solution a number of standard methods exist to achieve such small alignment. we found that swelling of cross-linked polymers inside the nmr tube results in anisotropic gels. peptides in such a gel phase exhibit well resolved spectra of the partially aligned molecules. this allows to scale the orientation depending on the cross-linking of the polymer, the thickness of the unswollen stick or the temperature. rdcs can now easily be measured in natural abundance in peptides 3] all common nmr solvents can be used. with the chiral gel gelatin it is possible to discriminate d-and l-alanine to determine enantiomeric purity. the procedure is demonstrated to refine the solution structures of peptides such as cyclosporin a, somatostatin analogues and others galia blum, 1 georges von degenfeld, 2 kinneret keren, 3 misregulation of cysteine protease activity is associated with numerous pathologies ranging from cancer to autoimmune disease. protease activity is controlled by a delicate balance of many factors such as levels of natural inhibitors and posttranslational modifications. thus developing a detection method for monitoring protease activity rather than abundance is desirable. here we describe the design and synthesis of a novel class of chemical tools, activity based probes (abps), that detect protease activity. these probes are composed of a fluorescent tag and its cognate quenching group, a peptide recognition scaffold, and a reactive "warhead". these fluorescently quenched "smart probes" covalently modify protease active sites in a fashion that is dependent on activity of the protease. this results in loss of the quenching group, producing a fluorescent signal. we report the production of selective, cell permeable activity based probes for the study of papain family cysteine proteases in cells and whole animals. these probes are used to monitor real time protease activity in living cells using fluorescence microscopy techniques as well as standard biochemical methods. key: cord-005337-3f6pwyy3 authors: yoon, hyun kyung; jung, sang taek; kim, jae-ho; yoo, tae hyeon title: recent development of highly sensitive protease assay methods: signal amplification through enzyme cascades date: 2013-01-04 journal: biotechnol bioprocess eng doi: 10.1007/s12257-012-0545-9 sha: doc_id: 5337 cord_uid: 3f6pwyy3 proteases are involved in almost all biological processes, and therefore, aberrant activity of many of these enzymes is an important indicator of disease. various methods have been developed to analyze protease activity, among which, protease assays based on resonance energy transfer are currently used most widely. however, quantitative methods with relatively higher sensitivity are needed, especially for disease diagnosis at early stages. one of the strategies to achieve higher sensitivity is to implement signal amplification of the protease activity. in this review, we briefly summarize the protease assay methods based on resonance energy transfer, and then elaborate the efforts to develop sensitive protease assays through signal amplification by using enzyme cascades. proteases (or proteolytic enzymes) hydrolyze the peptide bond of proteins by recognizing the side chains of specific amino acid sequences. approximately 2% of human genes encode proteases or their homologs, and proteases are involved in various biological processes, such as development, immunity, blood clotting, and wound healing [1, 2] . therefore, aberrant protease activity is associated with various diseases, including cancer, cardiovascular disease, alzheimer disease, inflammatory disease, and virus-related diseases [3] [4] [5] [6] [7] . to treat diseases resulting from hyperactivity of proteases, small molecule inhibitors have been developed. inhibitors against matrix metalloproteinase (mmp) and cathepsin, which play an important role in cancer metastasis, have been actively investigated [4, 8, 9] . protease inhibitors against the hiv protease are one of the most successful approaches to controlling the disease [7] . on the other hand, in diseases that are characterized by low or no protease activity, recombinant proteases are introduced into humans; for example, factor ix for hemophilia b and tissue-plasminogen activator (tpa) for breakdown of blood clots [10] . because of this relevance of proteases to disease states, the activity of specific proteases is an important indicator in the diagnosis of many diseases. for example, serine protease kallikrein 3, also known as prostate specific antigen, is a diagnostic marker for prostate cancer [11] . cathepsin, urokinase, and mmps are also known as markers of cancers [4, 8, 12, 13] . in addition, high activity of calpain is reported to be associated with altered calcium homeostasis, resulting in various pathologies [14] . a number of methods have been developed to assay proteases. immunoassays that rely on capturing proteases of interest by using specific antibodies have been developed to detect their abundance [15] . however, it should be noted that the protease activity, rather than its quantity, is indicative of disease states. consequently, the immunological methods have limitation, and are rarely applied in screening protease inhibitors. traditional biochemical methods, such as liquid chromatography and gel electrophoresis, have also been used to measure the activity of proteases [16] ; however, most of them are timeconsuming, and thus, cannot be easily adapted for highthroughput analysis of samples. recently, resonance energy transfer (ret)-based approaches have been actively investigated [17, 18] . two molecules, involved in ret, are linked by peptide substrates and cleavage of the substrate separates the two molecules and alters attributes of detectable signals. in the first part of this review, we summarize these methods briefly. early diagnosis of disease is closely associated with the likelihood of success in treatment of many diseases, and methods with high sensitivity and low noise are needed to facilitate early diagnosis. in the later parts, we introduce one of the strategies for developing sensitive protease assays, in which the signals generated by proteases are amplified through a process of enzymatic cascade. ret or fluorescence resonance energy transfer (fret) are processes in which a donor chromophore, in its excited state, transfers energy to an acceptor chromophore (typically, at a distance closer than 10 nm to the donor) via nonradiative dipole-dipole coupling. in the protease assays based on fret, the donor and acceptor molecules are linked together through short peptide substrates, and cleavage of the peptides results in reduction of the fret efficiency ( fig. 1) [17, 18] . two types of systems have been developed. in the first system (fig. 1a) , the donor is a fluorophore, and the acceptor is a quencher. the emission spectrum of the donor overlaps with the absorption spectrum of the acceptor, and the quencher reduces the intensity of fluorescence from the fluorophore. upon hydrolysis of the peptide substrate by protease, the donor and the acceptor move apart, and the emission of light from the fluorophore is restored. in the second configuration, a second fluorophore instead of the quencher can be linked to the donor fluorophore, (fig. 1b) , and the acceptor absorbs light from the donor and emits light of a different wavelength. cleavage of the peptide linker between the two fluorophores results in an increase in the fluorescence from the donor, and in the second system, a reduction or elimination of the acceptor fluorescence. fret methods have been widely used to assay protease activities because of its advantages, especially coming from the fact the signal is based on fluorescence [17, 18] . compared to the traditional biochemical methods, the signal-to-noise ratio is high, the signal can be measured without any additional purification step after reaction, and the assay cost is generally low. in particular, the platform can be easily developed into a high-throughput assay method, which makes it possible to analyze the samples in parallel for determining the substrate specificity of a protease or for finding protease inhibitors [19] [20] [21] [22] . the chemical compounds inhibiting proteases can then be developed further into therapeutics for diseases resulting from hyperactivity of proteases. in addition, these assays can also be used to reverse-engineer desired substrate specificity for a given protease. for instance, a highthroughput fret-based method for assaying ompt endopeptidase activity was used for engineering the substrate specificity of the enzyme [23, 24] . various organic dyes have been used as donors and acceptors [18, 25] . in particular, with the development of new chromophores with different absorption and emission wavelengths, various combinations are now possible, which enables multiplexed analyses of samples. despite advantages with using synthetic organic chromophores, their applications are limited because of some unfavorable inherent photophysical properties [17] . recently, much attention has been focused on synthesis of nanoparticles with enhanced properties, such as photostability, absorption capacity, quantum yield, and fluorescence lifetime, compared with those of organic dyes [17, 18] . with the discovery and engineering of new fluorescent proteins, protein chromophores have emerged as alternatives to synthetic probes [26] . fluorescent proteins are linked to synthetic compounds, such as organic dyes or nanoparticles, or two fluorescent proteins are connected to each other through a peptide linker. in the latter case, the entire protease sensor system can be expressed in a recombinant form in engineered cells, and the protein fret pairs can be used for monitoring protease activity inside the cells. however, synthetic chemical compounds generally have difficulty in penetrating the cellular membrane, thus, limiting their application in vivo. one limitation of fret-based methods that employ fluorescent chromophores as donors is the requirement for external luminescence to initiate fluorescence transfer. in addition, nanoparticles are not usually used as acceptors because they have broad absorption spectra, and thus, can be excited by external light that is used for exciting donor probes. in order to overcome these drawbacks, the luciferase enzyme has been investigated as a source for photon emission, in a process referred to as bioluminescence resonance energy transfer (bret) [17] . luciferase oxidizes luciferin into oxyluciferin, which relaxes back to the ground state by emitting a yellow-green light. because an external light source is not needed for excitation, bret methods have a lower background signal and usually have higher sensitivity than fret-based methods. detection of small amounts of marker proteins enables disease diagnosis at early stages, which often correlates with success in the treatment of these diseases. quantitative methods with high sensitivity and low noise are crucial for developing these diagnostic methods. even though fretbased protease assay methods have significantly improved with advancements in technologies for synthesizing fluorescent molecules and for light-detection instruments, there is still a need to develop new assay methods with higher sensitivity, while maintaining at least the same level of noise. one strategy for improving the assay sensitivity is to take advantage of a signal amplification processes via enzyme cascades ( fig. 2 and table 1 ). in these methods, a protease of interest activates another enzyme by removing the restrictions on the enzyme via a cleavage event, and the activated enzyme then generates detectable signals. these methods include signal amplification steps by reporter enzymes, and the degree of amplification is dependent on the catalytic activity of the activated enzymes. in the remaining part of this review, we will summarize recent research focused on developing methods of measuring protease activity utilizing the enzyme cascades. 3.1. pro-protease protease sensors a recent report described an assay method for enteropeptidase, which employs a naturally occurring enzymefig. 2 . signal amplification strategy using enzyme cascades. a protease activates a zymogen into an active one, which then generates a detectable signal. the activated enzyme can convert more than one substrate; thus, the protease activity signal is amplified, and the readout signal is theoretically higher than that generated directly by the protease activity, such as the signal generated in fig. 1 . autoinhibited split luciferase luciferin luminescence tev caspases [40, 41] autoinhibited split lactamase fluorocillin fluorescence tev [40] phospholipase a 2 nbd c 6 -hpc fluorescence sumo protease [34] cascade reaction. enteropeptidase is a serine protease and converts trypsinogen into active trypsin by cleaving the nterminal peptide (ddddk) of the zymogen [27] . in this assay, trypsinogen serves as the substrate for enteropeptidase, and the activated trypsin generated by the action of enteropeptidase cleaves a fret peptide substrate. the signal generated by enteropeptidase is amplified by the catalytic activity of trypsin. to develop the assay method, the authors first optimized fret peptide substrates of trypsin based on the fret efficiency and its cleavage efficiency/specificity, and further tested a range of enteropeptidase concentrations, using the optimized substrates and trypsinogen. the limit of detection (lod) was around 200 fm enteropeptidase in a complex biological mixture of escherichia coli lysate, as well as in a buffered solution. this is probably the lowest lod reported for any enteropeptidase assay, and the improved sensitivity is probably attributable to the signal amplification by the enzymatic cascade. an enteropeptidase assay is, perhaps, of limited clinical significance. however, the authors mentioned that the system can be adapted for the detection of any other protease. to apply this strategy for other proteases, the nterminal sequence of trypsinogen should be engineered in such that the protease of interest cleaves the modified sites; while the engineered trypsinogen remains inactive. one, and seemingly the only, approach is to insert a peptide sequence that the protease of interest recognizes and cleaves between the n-terminal peptide and trypsin. however, small changes in protein sequences can alter the function/structure of proteins, and additional studies, especially using proteases that are disease markers, are necessary to generalize the strategy employed in this study. verheijen et al. took a similar approach to develop an assay method for mmps, which are known to be involved in cancer metastasis [28] . pro-urokinase (pro-upa) is activated to urokinase (upa) through proteolytic cleavage by plasmin, and the activity of upa can be detected by using a chromogenic substrate (pyro-glu-gly-arg-p-nitroanilide). to engineer a form of pro-upa that can be activated by mmps instead of by plasmin, the authors replaced the sequence of amino acids in pro-upa that is recognized by plasmin (prfl ↓ iigg, where the arrow indicates the cleavage site) with one that can be hydrolyzed by many mmps (rplg ↓ iigg). using this system, the authors observed an increased mmp activity in synovial tissue extracts from patients with rheumatoid arthritis, compared to the activity of extracts from patients with osteorarthritis. the samples tested in this study might not have detectable upa activity, enabling detection of increased activity. however, blood and urine, which are most widely used for disease diagnosis, have significant activity of the reporter enzyme, upa, which definitely imposes a limitation on the clinical application of this assay method. firefly luciferase catalyzes the oxidation of firefly luciferin in the presence of mg·atp and oxygen into oxyluciferin, which emits a yellow-green light upon relaxation. luciferase provides high sensitivity and a wide dynamic range, and it has been widely used as both an in vivo and an in vitro bioluminescence reporter. in an attempt to exploit the beneficial properties of luciferase, fan et al. engineered luciferase asprotease sensors [29] . firefly luciferase has 2 domains, a large n-terminal domain and a small cterminal domain; both domains are connected through a hinge-like linker. the c-terminal domain rotates and translocates to the n-terminal domain upon substrate binding (fig. 3a) . based on these structural features, the authors engineered a circularly permuted construct: the n-and c-termini were connected through a linker that included sequence cleavable by a protease, and new c-and n-termini were created at the 233 and 234 positions, respectively (fig. 3b) . the linker restricts the conformational change induced by substrate binding, and the circularly permuted luciferase exhibits very little luminescence, several 1,000-fold lower than the wild-type enzyme. however, protease treatment increases the luminescence, in the range of 100 ~ 1,000-fold, depending on the specific protease and cleavable sequence used. laxmane et al. took another approach to engineer luciferase enzymes with attenuated activity, which can be activated by the action of caspase-3 [30] . the authors constructed caspase-3 reporters by fusing the estrogen receptor regulatory (er) domain to the c-terminus alone, or to both the n-and c-termini of firefly luciferase, with a caspase-3 cleavable sequence (devd) in the linker region between er and luciferase (fig. 3c) . the fusion of the er domain silences the activity of the reporter, and cleavage of the linkers by caspase-3 restores the luciferase activity. the mechanism by which the er domain inhibits luciferase has not been elucidated; however, the association of the er domain with heat shock proteins seems to play a role in the attenuation of luciferase activity [30] . in the case that both n-and c-termini of luciferase are fused to the er domain, the cleavage of the linkers resulted in approximately 10-fold increase in luminescence. in the study, the caspase-3 activity induced by tumor necrosis factor α-related apoptosis-inducing ligand (trail) was monitored real-time in tumors implanted in mice. despite the successful applications of the engineered luciferases, the systems have an important limitation. the enzymes are unstable in their purified forms, and the applications are restricted to in vivo bioluminescence or to in vitro analyses in an unpurified state, such as in cell lysate and in cell-free translation reactions. however, a system with a defined composition with purified proteins is needed in many cases to develop standardized diagnostic methods for disease detection. there are more stable luciferase enzymes from other organisms [31] , but they have to be engineered to have the desired properties, which can sometimes be extremely difficult. 3.3. sumo-pla 2 fusion-protein protease sensors sumolyation, wherein a small ubiquitin-like modifier (sumo) is covalently attached to the ε-nh 2 group of a lysine residue in proteins, through a series of enzymes (e1 activating enzyme, e2 conjugating enzyme, and e3 ligase), is a posttranslational modification and is known to be involved in many cellular processes, such as transport, transcription, apoptosis, and protein stability [32] . sentrinspecific proteases (senps) are isopeptidases that remove sumo moieties from proteins [32] . sumolyation is a dynamic process, and thus, the activity of sumo proteases is important in understanding sumo-related biological processes. phospholipase a 2 (pla 2 ) is an enzyme that releases fatty acids from the second carbon of glycerol and hydrolyzes fluorogenic substrates, such as 2-(6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl-1-hexadecanoyl-snglycero-3-phosphocholine (nbd c 6 -hpc). the enzyme requires a free amino terminus for catalytic activity [33] . by using these features of pla 2 , the researchers at progenra developed an assay platform for senps by constructing a fusion protein, sumo-pla 2 , which itself is inactive [34] . senps remove sumo from the fusion protein, and the activated pla 2 hydrolyses nbd c 6 -hpc and generates a fluorescence signal. leach et al. used this assay system to determine km values and to characterize inhibitors of sumo proteases [34] . split protein (or protein fragment) complement methods have been widely used to study biomolecular interactions [35, 37] . a protein is split into two fragments, and each fragment is fused to proteins of interest. when the two proteins interact with each other directly, or via another molecule, the split fragments are assembled into an active protein. autoinhibition is a naturally occurring mechanism for regulating protein activity: the protein has a polypeptide pseudosubstrate that blocks access to its active site, and the inhibitory region can be displaced through a conformational change or removed by a cleavage [38, 39] . shekhawat et al. employed these two mechanisms for regulation of protein activity, split protein complementation, and autoinhibition, to engineer protein reporters that can be activated by the action of protease (fig. 3d ) [40] . they used previously developed split protein complement systems: firefly luciferase and β-lactamase. one half of the reporter is linked to an antiparallel heterodimeric coiled coil (a-b), in which the a-b) is autoinhibited, and complementation of the two split fragments is thus prevented [40] . two coils are linked through a protease-cleavable linker, and the other half is linked to a coil (b'), which can dimerize with a. the heterodimeric coiled coil (a-b), which is autoinhibited, has a very low binding affinity to b', and the complementation of the 2 fragments is, therefore, unlikely. however, when a protease cleaves the linker connecting a and b, the interaction between a and b' can occur, and the split halves then assemble into an active reporter, such as luciferase or β-lactamase. using these systems, the authors developed and optimized protease sensors for the tev protease and caspase-3. the best luciferase sensor for tev provided a 1,000-fold increase of signal after protease treatment. in addition, logic gates were constructed by fusing autoinhibited heterodimer coiled-coils to both split halves. in a later study, the same group reported a panel of caspase sensors, which were used to investigate the substrate specificities of caspases and caspase activation pathways [41] . the protein sensors in this study were expressed using cell-free translation systems and then used to assess caspase activity in mammalian cytosolic extracts. however, it is plausible that the commercially available kits for in vitro translation would include proteases that activate the sensors. actually, when the caspase sensors were expressed using a rabbit reticulocyte lysate (rrl), significant luminescence signals were observed without the addition of a caspase, which was attributed to endogenous caspase activity in rrl. in addition, as mentioned above, the sensors must be expressed immediately before analysis, which can be an obstacle in developing standardized methods for analysis or diagnosis. cycling probe technology (cpt) is a technique originally developed for detecting specific dna sequences by using the unique property of rnase h, which hydrolyzes the 3'-o-p bond of rna in a dna/rna duplex [42] . kim and chung exploited the advantages of cpt to amplify the signal of a protease activity assay. this strategy differed from the ones that use the enzyme cascades that have been described so far, but the signal amplification method is worth introducing in this review [43] . the system used in this study included two kinds of gold nanoparticles (gnps), gnpa, in which the gnp is conjugated to a peptide-dna complex, and gnpb, in which the gnp is conjugated to a rna-fluorescein isothiocyanate (fitc) complex. gnpb particles were also pegylated to minimize heteroduplex formation between the gnpa dna and gnpb rna. thus, rnase h was prevented from cleaving the single-stranded rna of gnpb, and the fluorescence of fitc was quenched by gnps. when a protease of interest cleaves the peptide sequence linking the dna and gnpa, the dna oligomers are released from the nanoparticles and diffuse, eventually forming dna/rna duplexes with the rna in gnpb. duplex formation allows rnase h to hydrolyze the rna linked to gnpb, and the quenched fluorescence of fitc is thus recovered. dna oligomers, which are a product of the protease activity, are not consumed by the rnase h reaction, the cycle of duplex formation and rna hydrolysis can be continued, serving as the signal amplification step. the authors applied this system to the mmp2 protease, and the sensitivity of the protease was improved, to the detection of mmp2 at levels as low as 10 pm. proteases play important roles in diverse biological processes and are important markers of a number of diseases. various methods have been developed to analyze their activities, and the protease assay methods based on ret are, currently, the most common approaches. however, new tools with relatively higher sensitivity and at least the same level of noise, if not a further reduction in noise, are still needed. one solution to resolve this problem are the approaches that rely on amplifying the signal of protease activity by using enzyme cascades, and several specific strategies have been attempted so far. improved sensitivity has been demonstrated for these methods, but the optimization of these methods or development of new ones is required for application to diverse purposes. protease proteomics: revealing protease in vivo functions using systems biology approaches targeting proteases: successes, failures and future prospects dynamic imaging of protease activity with fluorescently quenched activity-based probes cancer. proteases--invasion and more protease-sensitive fluorescent nanofibers a genomic perspective on human proteases as drug targets discovery of next generation inhibitors of hiv protease matrix metalloproteinases: multifunctional contributors to tumor progression application of activitybased probes to the study of enzymes involved in cancer progression proteases as therapeutics the control of prostate-specific antigen expression and gene regulation by pharmacological agents cathepsin d in breast cancer: mechanisms and clinical applications, a 1999 overview fluorescent peptide probes for in vivo diagnostic imaging imaging calpain protease activity by multiphoton fret in living mice a one-step sandwich enzyme immunoassay for human matrix metalloproteinase 7 (matrilysin) using monoclonal antibodies application of in-gel protease assay in a biological sample: characterization and identification of urokinase-type plasminogen activator (upa) in secreted proteins from a prostate cancer cell line pc-3 analysis of protease activity using quantum dots and resonance energy transfer protease sensing with nanoparticle based platforms high throughput screening of potentially selective mmp-13 exosite inhibitors utilizing a triple-helical fret substrate activity-based fingerprinting of proteases activity based fingerprinting of proteases using fret peptides activity-based fingerprinting and inhibitor discovery of cysteine proteases in a microarray engineering of protease variants exhibiting high catalytic activity and exquisite substrate selectivity highly active and selective endopeptidases with programmed substrate specificities using specificity to strategically target proteases using gfp in fret-based applications highly adaptable and sensitive protease assay based on fluorescence resonance energy transfer modified proenzymes as artificial substrates for proteolytic enzymes: colorimetric assay of bacterial collagenase and matrix metalloproteinase activity using modified pro-urokinase novel genetically encoded biosensors using firefly luciferase noninvasive real-time imaging of apoptosis redshifted renilla reniformis luciferase variants for imaging in living subjects protein modification by sumo active site and catalytic mechanism of phospholipase a2 detection and characterization of sumo protease activity using a sensitive enzyme-based reporter assay beta-lactamase protein fragment complementation assays as in vivo and in vitro sensors of protein protein interactions split ubiquitin as a sensor of protein interactions in vivo kinetics of regulated protein-protein interactions revealed with firefly luciferase complementation imaging in cells and living animals reprogramming control of an allosteric signaling switch through modular recombination autoinhibitory domains: modular effectors of cellular regulation an autoinhibited coiled-coil design strategy for split-protein protease sensors comprehensive panel of turn-on caspase biosensors for investigating caspase specificity and caspase activation pathways specific and sensitive detection of nucleic acids and rnases using gold nanoparticle-rna-fluorescent dye conjugates proteolytic fluorescent signal amplification on gold nanoparticles for a highly sensitive and rapid protease assay the authors acknowledge financial support from the new key: cord-027712-2o4svbms authors: urošević, vladimir; andrić, marina; pagán, josé a. title: baseline modelling and composite representation of unobtrusively (iot) sensed behaviour changes related to urban physical well-being date: 2020-05-31 journal: the impact of digital technologies on public health in developed and developing countries doi: 10.1007/978-3-030-51517-1_13 sha: doc_id: 27712 cord_uid: 2o4svbms we present the grounding approach, deployment and preliminary validation of the elementary devised model of physical well-being in urban environments, summarizing the heterogeneous personal big data (on physical activity/exercise, walking, cardio-respiratory fitness, quality of sleep and related lifestyle and health habits and status, continuously collected for over a year mainly through wearable iot devices and survey instruments in 7 global testbed cities) into 5 composite domain indicators/indexes convenient for interpretation and use in predictive public health and preventive interventions. the approach is based on systematized comprehensive domain knowledge implemented through range/threshold-based rules from institutional and study recommendations, combined with statistical methods, and will serve as a representative and performance benchmark for evolution and evaluation of more complex and advanced well-being models for the aimed predictive analytics (incorporating machine learning methods) in subsequent development underway. the urban public health, well-being monitoring, and prevention are recently being transformed from reactive to a predictive and eventually long-term risk mitigating systems, through a number of research initiatives and projects, such as the ongoing pulse project (participative urban living in sustainable environments, funded from the eu horizon 2020 programme) focusing on the chronic metabolic and respiratory diseases (such as type 2 diabetes and asthma) affected or exacerbated by the preventable or modifiable environmental and lifestyle factors, and well-being/resilience. a major challenge in the project is the modelling and assessment/prediction of citizen well-being from the collected and processed big data of unprecedented variety and from highly heterogeneous sources (health and vital activity personal data obtained through wearable devices and other sensing technologies, geo-located online surveys, open/public smart city datasets…), on individual and collective (population/cluster) levels. overall well-being and its main domains (vitality, supportive relationships, stress levels…) are all significant factors affecting the onset and exacerbation of the stated chronic diseases which are becoming more and more widespread and progressing in urban environments, and overall resilience of citizens and urban communities is increasingly important against other pertaining global and sustainability challenges, like climate change. the proposed and deployed elementary statistical model presented in this paper is to be the basis for interpretation and contextualization of changes to well-being, and a performance benchmark for evaluation and comparison of more complex and advanced well-being models of the aimed predictive analytics and final intelligent system (incorporating machine learning methods) in subsequent development, supporting the pulse phos (public health observatories established for the relevant policy making and execution in smart cities). the activity and vital/health parameters data measured mostly unobtrusively by wearable devices (wristbands, smartwatches) have particular significance for behaviour analysis and change recognition in pulse, as these are the input data streams with highest volume, acquisition "velocity", and temporal resolution/granularity of all the various data collected in the project, and therefore practically the most (and only) suitable data comprising the sufficiently continuous and non-sparse time series over months, to properly derive or construct the behavioural patterns and analyze behaviour changes. recent studies performed by the stated major wearable device manufacturers over billions of records of temporal measurements data [1, 2], as well as the experiences from projects like the just concluded city4age (www.city4ageproject.eu) [3, 4] , show the significance and general predictive ability of the measured main vital/health and activity parameters (walking, climbing stairs, physical activity/exercise, heart rate data, consumed calories…) for overall health and physiological/physical well-being assessment. the additional complementary socio-demographic, health, lifestyle/habits and environmental data in less frequent temporal resolution, ingested from the open/public datasets or manual "obtrusive" inputs, are combined to cross-check, adjust and improve integrity of the recognized behaviour changes derived from the main timeseries data acquired through the wearable devices. we adopt a combined knowledge-and data-driven approach in detection and characterization of relevant behaviours that denote significant variations in well-being, with multi-level hierarchical model topology and range/threshold based computational rules as basic primary formal knowledge structures, and statistical analytics as baseline (and performant) data-driven detection methods. the complexity of human behaviours is commonly represented through multi-level hierarchical structured models, decomposed to more granular "units" like activities and action events [5, 6] , with multiple variables from behavioural, physiological and environmental domains of well-being known to additionally increase complexity and dimensionality [7] . there are other contending approaches, like the monitoring and analysis of individual well-being or behavioural domain indicators or determinants independently in parallel, without hierarchical structuring and substantial synthesis into fewer higher-level composite factors or score(s) [8] . most, including the adopted and followed approach works (like [9] ), are comprehensively covered or referenced in the encyclopedia of quality of life and well-being research (springer 2014) that summarizes recent research works related to well-being and quality of life in spanned various research and policy-making/implementation fields. main advantages of a few composite synthetic indicators/factors over a battery of multiple separate indicators, namely: • ability to summarize complex and multi-dimensional real-life phenomena or domains (like well-being), • easier for interpretation and comparison among (socio-demographic, geospatial/regional…) groups or population clusters, • more effective for comprehending overall trends, particularly when a number of the underlying indicators denote opposing-trend changes, are of crucial significance in usage and context settings of the pulse project, with over 60 indicators formalized in the initial knowledge-based well-being model topology from the systematization of collected data, and with • visible set of indicators to various stakeholders (policy makers, researchers, general public) needing to be minimal without omitting important underlying information, • and collaboration, communication and comparison of complex dimensions by various stakeholders needing to be most straightforward, facilitated and effective. we therefore propose two complementary approaches for synthesis of the composite well-being indicators composed from underlying streamed iot-sourced timeseries data in the context of pulse. the indicators summarize multi-dimensional aspects of citizen well-being and enable the assessment of individual and synthesized collective urban well-being over time. the notion is illustrated through analysis within the scope of four representative and characteristical key summary indicators of citizen health and fitness, derived from activity and vital/health parameters measured, as stated, using wearable sensing devices: motility, physical activity, sleep quality and cardio-respiratory health/fitness (fig. 1) . in the first approach, daily and intra-daily underlying measurements (table 1 ) are used to estimate levels of adherence to rule-and range-based recommendations matured from institutional knowledge of relevant authorities and population-significant studies in the field, accumulated for over decades in the stated four example domains of motility, physical activity, sleep quality and cardio-respiratory fitness [8, 10, 11] . the complementary data-driven statistical approach is predicated on standard scores that denote the number of standard deviations that a given measurement deviates from the sample mean. this approach allows comparison of individual scores to the corresponding norm groups stratified by common socio-demographic parameters (age, gender…), when considered conditionally independent nodes in the complete model topology. it also allows to place a score for any individual and variable with respect to alternative descriptive statistic or measure of central tendency (variable median, geometric mean, standard deviation or error), so that more accurate or optimal comparison for specific variable distribution can be made. the data are collected by several types of health and fitness wearable tracker devices manufactured by fitbit, garmin and asus, monitoring physical and walking activity, sleep and heart/cardio parameters, for over 300 recruited citizens participating in the study in 7 global testbed cities (barcelona, birmingham, new york, paris, pavia(italy), singapore, and keelung/taipei), supplied with wearable tracker devices by the project. physical activity level as a single measure is mainly expressed in terms of time spent and calories burned while performing light/soft, moderate, and intense/vigorous physical activity. walking activity is captured with walked steps, distance, speed, and climbed stairs/floors measurements. heart rate measures capture time spent in different target heart rate zones (like peak, cardio, fat burn), resting and maximal heart rate (hr max ), and some still experimental measures like systolic and diastolic blood pressure, measured by the newest recently released devices such as asus vivowatch bp, but not yet acquired in significant volume sufficient for analysis. the peak heart rate zone by default definition ranges from 85 to 100% of person's maximum heart rate (hr max ), the cardio zone ranges from 70 to 84% of hr max , and the fat burn zone ranges from 50 to 69% of hr max . sleep quality/hygiene measures mainly capture time spent in defined phases of sleep. all the processed measures are listed in table 1 , collected or aggregated with a default daily periodicity, except the ones in gray-shaded rows which are acquired in higher intra-daily temporal resolution, mostly once in every 15 min or up to once in a minute, depending on the variable. in addition to stated behavioral time-series data, an extensive set of personal sociodemographic, profile (age, gender, ethnicity, educational and marital status, employment status and occupational environment…), as well as health state, risk factors and habits, lifestyle, neighbourhood and quality of life assessment, and other relevant behavioural data are manually input/submitted on each citizen participating in the study via online forms, composed from adapted relevant survey/assessment instruments for each specific field, like framingham, euroqol-5, ipaq-sf. these data are geolocalized to the residence location of each responding citizen for the purposes of analytics of collective/community well-being, and are collected from a greater number of recruited respondents, but just in rare cases in more than one iteration over time due to the high number and scope of covered variables, and therefore suitable for a broad but mainly static "snapshot" assessment of current well-being state rather than for behaviour change model and analytics. incorporating both these static and iot-sensed temporal data into a fully comprehensive predictive well-being model is an ongoing task in progress throughout the end of the project, with results to be presented in other upcoming publications. physical activity in our first approach stated above in sect. 2 can be discretized using several common baseline categorizations related or derived from the above mentioned relevant institutional/governmental and professional expert guidelines for the urban population groups. the example approach taken in the recent health survey of england from 2016 [12] compared well-being and mental health of adults in different sociodemographically stratified population groups by physical activity, among others. the activity level categories used in the analysis were the following: • meets aerobic guidelines: at least 150 min moderately intensive physical activity or 75 min vigorous activity per week or an equivalent combination of these • asserted activity: 60 to 149 min moderate activity or 30-74 min vigorous activity per week or an equivalent combination of these • low activity: 30 to 59 min moderate activity or 15 to 29 min vigorous activity per week or an equivalent combination of these • inactive: less than 30 min moderate activity or less than 15 min vigorous activity per week or an equivalent combination of these, and the corresponding linear scaled scoring function denotes "meets aerobic guidelines" with a score of 4, "certain activity" -3, "low activity" -2, and "inactive" with 1. this baseline scoring scale, besides sufficient granularity and robustness exhibited in referenced comprehensive studies, is also convenient for • mapping to the defined activity level categories used as input parameters for the consensus models for prediction of risk of type 2 diabetes (t2d) and asthma onset and exacerbation, developed for the pulse project [13, 17] • quantification of longer-term and/or periodic activity level behaviours directly from categorized daily or incidental activity level values as measured and acquired from the wearable tracker devices through relevant apis (light/soft, moderate, and vigorous/intense activity). similarly, the authors in [14] and [15] demonstrate the following referent threshold ranges of the number of daily walked steps to be used for classification of walking activity in healthy adults, and the corresponding scoring function linearly assigning the following 1-5 integer scores to the classification categories: highly active (12,500 or more steps/day) -5, active (10,000-12,499 steps/day) -4, somewhat active (7,500-9,999 steps/day) -3, lowly active (5,000-7,499 steps/day) -2, and sedentary (under 5,000 steps/day) -1. vo 2 max is the metric denoting the maximum amount of oxygen that an individual can use during intense exercise. it is widely and commonly used as an indicator of cardiorespiratory fitness. a simple generic estimate of vo 2 max of an individual can be obtained using their maximum and resting heart rates in the following formula, publised in [16] : vo 2 max % hr max hr rest ã 15:3 ml=ðkg ã minþ ð 1þ where hr max can be crudely estimated as 220age of the person. a relatively standard convenient and meaningful categorization of vo 2 max for western european and usa populations can be on a scale from 1 -very low, through 2 -low, 3 -fair, 4 -moderate, 5 -good, and 6 -very good, to maximal 7 -elite, depending of the individual's gender and age, with common categorization for males and females aged 6 to 75 published by shvartz & reibold in [11] . total average sleep duration in 24 h is a straightforward direct metric for assessing the quality of sleep in terms of longer-term stable behaviour across complete populations. the us national sleep foundation recently provided the following referent expert sleep duration recommendations (in terms of recommended (or not) threshold values for both oversleep and undersleep), categorized by precise granular age ranges [10] : these recommendations categorize possible output sleep duration times as either recommended, may be appropriate, or not recommended, and the optimal recommended duration is 7-9 h for majority of the populations. additionally, relevant recent findings like the extensive meta-analysis performed by the american diabetes association to assess the dose-response relationship between sleep duration and risk of type 2 diabetes [18] , have concluded that the lowest type 2 diabetes risk is for the average overnight sleep duration from 7 to under 9 h per day, and that both shorter and longer sleep durations than this optimum range denote up to 1.5 times increased risk (and up to 2 times increased cardiac conditions risk shown in the related studies [21] , also relevant in the project). we therefore slightly alter the may be appropriate category from the otherwise adopted recommendations from table 2 above to mildly risky, reflecting the importance of stated health risks in pulse, and the effect of common or periodically repeated behaviour patterns over months or years to the exasperation of the risks. this categorization will also consequently be communicated on the data visualizations and public health/prevention interventions and campaigns deployed and administered through relevant pulse system applications and modules (pho dashboards, pulsair gamified mobile app.) towards the citizens and urban communities, and the resulting function scores assigned to the categories are therefore: 1 for not recommended, 1.75 for mildly risky, and 2 for recommended, inversely proportional to the pesimistically estimated risks increase brought by shorter durations. complex eventual relations of detailed specific measured sleep parameters to well-being will be explored by more advanced methods in other subsequent work. from several existing elementary statistical approaches for aggregating the underlying dimensional indices and constructing the summary composite indicator value, we consider the weighted geometric mean of the four constituting dimensional indices as most adequate and appropriate for this specific well-being problematics: where summary dimensional indices denoted by the scoring function values are: i wwalking activity index, i pphysical activity/exercise index, i ssleep duration index, i ccardio-respiratory fitness index (through vo 2 max), and wt w , wt p , wt s , and wt c are respective weight factors, derived from expert assessments and rank data from relevant previous studies and experience, and assigned to adjust the relative importance and contribution of each of the indices to the resulting composite indicator value, per compositing methods outlined in [19] and [9] , or for derivation of composite un human development index (hdi). as all 4 constituting indices are directly proportional to the resulting composite indicator (i.e. the higher the activity levels or cardiorespiratory fitness scores, the higher the well-being), and low value of either of the four is significant for decreased overall composite (although there is some correlation between the indices -e.g. decrease in cardio-respiratory fitness in most cases causes decreased activity levels as well), the geometric mean is adequate for its sensitivity to low values of each individual constituting index, and ability to combine values on completely different scales without normalization required. initially assigned values of weight factors are 0.9 for i w , 1 for i p , and 1.05 for i s and i c , taking into account the importance of specific indices for respiratory disease and t2d risk, volatility of the collected data by now, and known overestimation of some measured variable values (like number of walked steps, vo 2 max estimate, or recognized sessions of cycling and some other exercise types) by the predominantly used wearable devices -fitbit charge 2 [20] . the weight factors are set as configuration parameters in the model, so they can be changed to fine-tune the composition according to the data insights acquired over time or the results of the validation described in sect. 5 below. time series of the values of the composite indicator are formed from weekly and monthly aggregations of underlying daily and intra-daily measurements into the 4 constituting index values. method for computing those values from the measured values of variables listed in table 1 above is as developed and introduced in [22] for synthesis of indicators and geriatric factors from the same source iot data, based in this case on univariate normalization of relative changes (quantified in standard scores, as stated above in the "approach" sect. 2) of acquired big temporal data during the complete study period, and then multivariate weighted linear aggregation of obtained normalized indicators and descriptive statistics into higher-level composite factors, to capture weekly and monthly behavioural patterns and trends, less susceptible to influence of outliers and ocassional notably deviating values. validation metric is the correlation with specific corresponding summary measure(s) of current well-being, self-reported by the respondent citizens through web and mobile app. questionnaires as mentioned above. they can be summarized from two relevant subset questionnaires: 1) european social survey (ess), and 2) euroqol-5d (eq5) survey instrument, both standardized (with minor adaptations) and common for measuring well-being in multiple continuous and/or repeated relevant europe-wide and national-level studies, and robust to some degree against extreme fully subjective bias. 15 statements of the ess questionnaire broadly cover social and most of the other aspects of personal and community well-being that the respondent rates on a 5-degree likert scale (strongly agree-4, agree-3, neither agree nor disagree-2, disagree-1, strongly disagree-0), the total possible questionnaire score thus ranging from 0, denoting the lowest/worst well-being, to 60 representing the optimum. eq5 instrument is focused on physical and mental health status and daily life activities measured in 5 dimensions (mobility, self-care, usual activities, pain/discomfort and anxiety/depression), also self-rated on a 5-degree scale from perceived worst to best like in ess. last question asks for assessment of the respondent's overall health state (hsa) on the current day, on the scale from 0 (worst) to 100 (best imaginable), also mapped to a number ranged from 1 to 5 by the formula 1 + 4 * hsa/100 for the purpose of this evaluation. total cumulative eq5 score thus ranges from 6 to 30. figure 2 below shows the correlation scatter plot of ess scores and composite well-being indices for 97 respondents of which 12 filled ees questionnaire twice, two filled it three times, and the rest only once during the observed period of 11 months. figure 3 shows the relationship between the composite well-being indices and the obtained eq5 scores of 107 respondents, 3 of which filled the questionnaire three times, 20 filled it twice, and the rest once during the observed data collection period. the analysis reveals a medium positive correlation of 0.424 (with the p-value of approx. 3.7 â 10 −7 ) between our constructed composite index and cumulative eq5 scores. the composite indicator and its constituting domain indices can therefore be considered promising for their intended purpose of basic represention of the urban physical well-being aspects modelled from a variety of heterogeneous underlying activity and health/vital parameters measured by iot wearable devices, summarized in 4 main dimensional and one overall derived score convenient for comparisons, interpretation and presentation to the end-users, particularly in the required shortest most concise manner and form, such as through a mobile app. ui or intervention messages. as almost half of the questions in eq5 are very remotely or not at all related to the physical well-being aspects summarized by the composite indicator, the correlation is expected to increase when the ongoing work in incorporating social and other wellbeung aspects fully in the model is completed. found small positive correlation of 0.287 (p-value 0.001) between the composite indicator and cumulative scores of ess questionnaire (in which most of the questions are not related to physical well-being) additionally points to the significance of this composite indicator to the overall well-being. the work also continues on the cleaning and pre-processing the data collected on the remaining monitored citizens, incorporation of machine learning methods in the model and exploration and modelling of the influence of detailed sleep and cardiac parameters, as well as of the sensed ambiental data, on the main well-being domains. the images or other third party material in this chapter are included in the chapter's creative commons license, unless indicated otherwise in a credit line to the material. if material is not included in the chapter's creative commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. ageing-friendly cities for assessing older adults' decline: iot-based system for continuous monitoring of frailty risks using smart city infrastructure a critical analysis of an iot-aware aal system for elderly monitoring semantic and fuzzy modelling for human behaviour recognition in smart spaces a scalable hybrid activity recognition approach for intelligent environments comparative impact study of the european social survey (ess) european research infrastructure consortium (eric) systematic scoping review of indicators of community wellbeing in the uk composite index construction national sleep foundation's sleep time duration recommendations: methodology and results summary aerobic fitness norms for males and females aged 6 to 75 years: a review health survey for england 2016: well-being and mental health. nhs digital health and social care information centre and the uk office for national statistics hapt2d: high accuracy of prediction of t2d with a model combining basic and advanced data depending on availability how many steps/day are enough? for adults estimation of vo2max from the ratio between hrmax and hrrest -the heart rate ratio method a bayesian network analysis of the probabilistic relations between risk factors in the predisposition to type 2 diabetes sleep duration and risk of type 2 diabetes: a meta-analysis of prospective studies indicators and methods for constructing a us human well-being index (hwbi) for ecosystem services research assessing the ability of the fitbit charge 2 to accurately predict vo 2 max sleep duration and risk of stroke events and stroke mortality: a systematic review and meta-analysis of prospective cohort studies data driven mci and frailty prevention: geriatric modelling in the city4age project empowering citizens through perceptual sensing of urban environmental and health data following a participative citizen science approach acknowledgment. this work has received funding from the european union's horizon 2020 research and innovation programme under the grant agreement no. 727816 (pulse). the performed research studies have all been granted ethical approval from the relevant irb authority in each pulse pilot testbed city (ethics committee of the parc de salut mar hospital in barcelona, through nhs health research authority iras (integrated research application system) in birmingham, new york academy of medicine irb in new york city, etc.), resulting from comprehensive multimonthly evaluation processes. the inclusion and exclusion methods and criteria for recruiting citizens have been specified in relevant previous publications of the project, such as in section 2.2.1. participation criteria in [23] . key: cord-260674-a0ejus6m authors: chopra, sakshi; ranjan, piyush; singh, vishwajeet; kumar, suraj; arora, mehak; hasan, mohamed shuaib; kasiraj, rhytha; suryansh; kaur, divjyot; vikram, naval k.; malhotra, anita; kumari, archana; klanidhi, kamal bandhu; baitha, upendra title: impact of covid-19 on lifestyle-related behavioursa cross-sectional audit of responses from nine hundred and ninety-five participants from india date: 2020-10-06 journal: diabetes metab syndr doi: 10.1016/j.dsx.2020.09.034 sha: doc_id: 260674 cord_uid: a0ejus6m background and aims: the impact of measures taken to contain covid-19 on lifestyle-related behaviour is undefined in indian population. the current study was undertaken to assess the impact of covid-19 on lifestyle-related behaviours: eating, physical activity and sleep behaviour. methods: the study is a cross-sectional web-based survey. a validated questionnaire to assess the changes in lifestyle-related behaviour was administered on adults across india using a google online survey platform. results: a total of 995 responses (58.5% male, mean age 33.3 years) were collected. an improvement in healthy meal consumption pattern and a restriction of unhealthy food items was observed, especially in the younger population (age <30 years). a reduction in physical activity coupled with an increase in daily screen time was found especially among men and in upper-socio-economic strata. quarantine induced stress and anxiety showed an increase by a unit in nearly one-fourth of the participants. conclusions: covid-19 marginally improved the eating behaviour, yet one-third of participants gained weight as physical activity declined significantly coupled with an increase in screen and sitting time. mental health was also adversely affected. a detailed understanding of these factors can help to develop interventions to mitigate the negative lifestyle behaviours that have manifested during covid-19. covid-19 is a global burden which continues to redefine daily lifestyle-related habits in a significant manner as the pandemic progresses through its different phases. public health recommendations and government measures taken to abate infection have indirectly impacted food availability, dietary quality, normal daily activities, access to recreational public settings, social activities, work and financial security [1] . these factors compound over time to radically change lifestyle-related behaviours, especially daily eating, activity and sleep behaviours that are known to be independent risk factors for metabolic complications such as obesity, diabetes and cardiovascular disorders [2, 3] . few preliminary studies from the west have highlighted a negative impact on various lifestylerelated behaviours as the potential implication of covid-19. however, these studies were done during the complete lockdown phase and suffer from methodological limitations like less representative sample and non-validated tools for data collection. moreover, the interplay of the severity of covid-19 infection with different social, economic and cultural constructs in determining the extent of changes in lifestyle-related behaviours might vary from country to country. there is a lack of evidence that evaluates the effect of covid-19 on lifestyle-related behaviours in india. it is important to investigate some key questions such as which lifestyle behaviours are most affected, how much is the impact of covid-19 on these behaviours, what are the reasons for these changes and which demographic section is the most impacted. considering these questions, we undertook this study to evaluate the overall impact of covid-19 on lifestyle changes experienced by individuals during the pandemic. the answers to these questions will establish a fundamental basis to develop appropriate recommendations for lifestyle modifications during this time. a web-based cross-sectional study was conducted on the general population to assess the impact of covid-19 on daily lifestyle-related practices such as dietary, activity and sleep pattern using a validated questionnaire. the study was approved by the institutional ethics committee this study was a rapid, large cross-sectional online survey conducted during the unlock phase (15 th august 2020 to 30 th august 2020) across various cities, towns and villages in india. the data was collected using google form web survey platform and telephonic interview. a standard study invitation message along with the link to the online survey was shared through personal and social contacts of the research group members via email, facebook, instagram, and whatsapp. we also asked the participants to share the study link to increase study participants, which allowed us to conduct a nationwide survey, especially during the pandemic situation. in cases, where participants had limited literacy levels or technical knowledge to fill the google form by themselves, the investigators conducted a telephonic interview and filled the form on their behalf. a brief description of the study, its objectives and the declaration of anonymity and confidentiality were given to the participants before the start of the questionnaire shared via google form. informed consent was taken from all the participants at the time of enrollment either by checking. participants were also requested to be honest in their responses. following this, the participants answered differential questions on the changes experienced in their lifestyle before and during the pandemic. during the survey, participants were able to stop study participation and leave the questionnaire at any stage before the submission process; if doing so, their responses would not be saved. responses were saved only by clicking on the "submit" button provided at the end of the questionnaire. the principle of maximum diversity was followed to recruit a representative sample for this study. quota sampling technique was used to identify the quotas based on different demographic variables such as age, gender, socio-economic strata and place of residence. the number of j o u r n a l p r e -p r o o f participants in each quota was compared with the prevalence of different categories in indian population and efforts were made to sustain maximum representativeness. a total of 1058 responses were collected using the google form link and telephonic survey, after excluding responses that met exclusion criteria such as younger participants (age <18 years), duplicates and invalid entries. the final data included 995 participants (as shown in supplementary figure 1 ). the electronic survey questionnaire was designed to assess changes in multiple lifestyle-related behaviors such as eating, physical activity, sleep and other health related behaviours during the covid-19 outbreak. the differential questionnaire used in this study was developed and validated as an extension of a short version lifestyle related practices questionnaire in indian adults [4] . the questionnaire has three sections assessing socio-demographic details, changes in lifestyle related behaviour and covid specific reasons for the changes in these behaviors. section a comprises questions relating to general information and demographic data, selfreported anthropometric data and one question of change in weight status during covid-19. section b consists of two parts with 24 items. part a (a1 to a24) assesses the baseline lifestylerelated behaviours and part b (b1 to b24) evaluates changes in different lifestyle related behaviors such as eating habits, physical activity and sleep pattern during the pandemic. the domain on eating behaviour consists of 12 items on meal pattern, portion size, frequency of meals, food group consumption pattern, emotional eating and intake of high fat, salt and sugar (hfss) foods and sugar-sweetened beverages (ssb) consumption. the domain on physical activity pattern has six items focusing on different components of activity such as aerobic exercise, involvement in household chores, leisure related activity, work-related sitting time and screen time. two items are for sleep patterns, one item for daily stress levels and two items for stress related addictive behaviours such as smoking and alcohol consumption. the five point likert-response choices are as follow: 'not routinely', 'one to two times a week', 'three to four times a week', 'five to six times a week' and 'almost daily'. the magnitude of the responses ranges from 5 (most acceptable behaviour) to 1 (least acceptable behaviour). section c has 6 items assessing the perceived covid-19 specific reasons for changes in lifestyle-related behaviours. j o u r n a l p r e -p r o o f descriptive statistics of the participants' baseline characteristics and responses were provided as frequency and percentage for categorical variables. continuous variables were reported as mean and standard deviation or median and range/interquartile range according to the distribution. the responses for before-covid-19 lifestyle scores and during-covid-19 lifestyle scores were assessed and these scores were subtracted for each item giving the mean difference scores which were associated with demographic variables. the association between the categorical variables was assessed using chi-squares test or fisher's exact test. the differences of continuous variables between two groups was assessed using t-test or wilcoxon test. while comparing more than two groups anova with bonferroni correction was done. for all analyses, p≤0.05 was considered as statistically significant. all statistical analyses were performed by using stata/se version 14.2 (statacorp lp, college station, tx, usa). the demographic details of the included participants (n=995) is shown in table 1 . the sample has slightly higher male participation (58.5%) with the mean age of 33.3 (14.5) (range, years. the representation from different socio-economic strata (according to kuppuswamy scale) and place of residence was fairly equal, with slightly greater number of participants from metropolitan cities (43.1%). the mean self-reported body mass index (bmi) was 24.8 ± 4.7 kg/m 2 . one-third participants reported a gain in weight during covid-19 pandemic. responses for differential items assessing the changes in lifestyle-related practice before and during covid-19 is given in table 2 . the habit of consuming meals routinely at regular intervals has slightly increased during covid-19 (42.5% vs 49.7%). the participants refraining from unhealthy eating behaviours such as consumption of fried food (64.1% vs 81.6%), junk food (44.3% vs 62.6%), fast food (53.2% vs 67.6%) and sugar-sweetened beverage (ssb) (50.1 vs 51.6%) also increased. participants reported marginal improvement in the frequency of j o u r n a l p r e -p r o o f consumption of different food groups such as fruits and vegetables (34 vs 37.8%), milk and its products (38% vs 40%) and pulses, meats and egg (18.2% vs 24%) during covid-19. in the physical activity domain, an increase in participants not routinely exercising for 30 minutes was observed (38.4% vs 50.4%). although, participants exercising more than three days a week (45.4% vs 45.1%) before the pandemic maintained the habit of exercising during the pandemic as well. participants refraining from routinely involvement in leisure-related physical activity also increased by more than double (29.4% vs 65.9%). one-third participants reported a daily screen time of 4-5 hours during covid-19 (13.7% vs 32.5%). participants reporting more than eight hours of sleep increased (10.2% vs 27.8%) but the overall quality of sleep marginally declined (50.7% vs 48.1%) and overall stress amongst participants increased (24.9% vs 38.2%). the comparison of mean scores of lifestyle related behaviours before and during covid-19 is shown in table 3 . there was a significant increase in routine consumption of meals at regular the frequency distribution of per unit difference in lifestyle scores before and during covid is shown in table 4 . the change in scores was calculated by subtracting during-covid lifestyle scores from before-covid lifestyle scores. in the eating behaviour domain, half of the participants experienced no change in regular meal pattern, whereas for 29.8% participants this habit was improved but for 18.56% this habit was worsened. the intake of high protein foods such as pulses, egg and meats increased during covid-19 (26.4%). the intake of unhealthy food items such as fast food (18.9%), junk food (1.98%), fried food (25.3%) and ssb (16.3%) improved by one unit. participants experienced a reduction in physical activity by 9.5% in comparison of the improved participants (22.05%) and leisure-related physical activity (45.63%) was three times higher than improved participants (15.68%). in addition to this, the daily sitting time increased for 33.07% participants. besides, the time spent daily on screen time increased by one unit in one-third of the sample (30.65%) and overall sleeping hours increased in one-fourth of the sample (25.53%). almost one-fourth (23.02%) participants reported an increase in stress level by one unit. although, overall social support from the family and friends (20.8%) during covid-19 improved as well. the reasons for change in lifestyle related behaviour is given in supplementary table 1 . factors such as fear of coronavirus infection (43.8%), preferring home-cooked food (25.2%) and less involvement in eating out and socializing (23.6%) were the prime reasons for improvement in healthy eating and decline in junk food consumption. although, participants involved in physical activity by walking (28.9%), at-home workout sessions (18.9%) and yoga (16%); adverse changes in physical activity levels were reported due to lack of motivation (24.5%), time availability (25.3%) and restricted access to parks, dance and fitness centre (28.6%). besides, participants' fear of getting infected by coronavirus (23.6%), worrying about their family (20.2%) followed by boredom and loneliness (18.2%) and financial loss (14.7%) were most commonly reported reasons for adverse changes in stress and anxiety levels during covid-19. j o u r n a l p r e -p r o o f the association of mean difference of during-covid domain-wise lifestyle scores from before-covid domain-wise lifestyle scores was studied with respect to different demographic groups as shown in table 5 . in the age category, a significant improvement in overall eating behaviour during covid-19 (2.44[6.49], p<0.001) was seen in the younger age group (≤30 years). besides, the overall physical activity worsen in all age groups (p<0.001). also, the overall physical activity worsened in both the genders, but men experienced a greater significant reduction in their activity status (-1. j o u r n a l p r e -p r o o f the outbreak of covid-19 and measures of its containment has evident impact on the lifestyle related behaviors in the population [5] . experts believe that lifestyle related predictors of weight gain and cardiometabolic risk are modifiable and should be screened and addressed during covid to prevent obesity and maintain general wellbeing [6] . the current study is a cross sectional web-based survey conducted to understand the impact of covid-19 on different lifestyle behaviors, severity of this impact across different demographic sections and covid-19 specific reasons for changes in lifestyle. we recruited a representative sample of 995 participants across india to complete a pre-validated questionnaire on lifestyle related behaviors using a webbased platform. the data collected was subjected to rigorous statistical analysis to generate robust inferences regarding the impact of covid-19 on lifestyle related behaviors in terms of both magnitude and direction. the key findings of the survey divulge certain trends in the eating habits and physical activity behaviour. firstly, a healthy eating trend was observed in terms of slight improvement in routine consumption of meals at regular intervals and consumption of protein-rich foods such as pulses, eggs and meat along with restricted intake of high fat, sugar, salt (hfss) food items, especially in the younger population (age <30 years). secondly, there was a significant reduction in moderate intensity aerobic exercises as well as leisure related activities coupled with an increase in daily screen and sitting time. overall, physical inactivity was comparatively higher in men and participants belonging to upper socio-economic groups. thirdly, quarantine induced stress and anxiety increased by a unit in almost one-fourth of the participants. the findings indicate that the participants improved slightly in terms of consuming meals at regular intervals in routine. regular meal pattern as a construct is often described as an individual's eating patterns at the level of a 'meal', such as a main meal (for example, breakfast, lunch or dinner) or a smaller-sized meal (for example, supper or snack) [7] . the consumption of nutritionally balanced small and frequent meals is associated with better dietary quality and is a common clinical recommendation for weight loss and reduction in metabolic comorbidities [8] . certain experts believe that a proportion of individuals may have marginally improved metabolism and other health outcomes during the covid-19 pandemic by adhering to the following dietary behaviors: (i) reducing meal frequency, (ii) consuming regular (i.e., breakfast j o u r n a l p r e -p r o o f (about 40% of daily total energy), lunch (30% of daily total energy) and dinner (30% of daily total energy) and having good quality meals (e.g., more fresh vegetables, good quality protein source, avoiding refined and high glycemic foods) [9] . the participants in our study also reported higher consumption of protein-rich foods such as pulses, eggs and meat. this is, however, contrary to the findings of another study conducted in the west, which found that daily consumption of regular meals had marginally lower contribution to the overall improvement in eating behavior during covid-19 (10) . a possible reason for this difference could be higher focus on home cooked food in the indian households. the results of this study highlight a significant but limited (mostly by one unit) improvement in quality of meals consumed by reduction in the consumption of calorie-dense fast food, fried food and ssbs. contrary to our findings, some studies suggest that confinement increased intake of hfss food items, which could be attributed to eating out of anxiety or boredom, a dip in motivation to maintain healthy eating or an increase in mood-driven eating [11, 12] . however, in our study that was conducted in india, the participants reported less socializing and eating out, preference to home cooked meals, time availability for meal preparation, incorporation of immunity-boosting foods to maintain health and better family support in maintenance of healthy eating pattern as prime reasons for reduction in unhealthy eating behaviors. it can also be noted that socializing and eating out practices mostly governed unhealthy food consumption in our sample. despite recommendations that covid-19 preventive measures should not hinder people from being physically active, present results show that there has been a decline in physical activity levels. a reduction in engagement in physical activity at all levels coupled with increase in daily sitting and screen time due to confinement was prominently found across the literature [10] . it is evident that government recommendations to limit outside movement and restrictions on social gathering (group sports and walking or exercise classes), availability (sports and gym facilities) and accessibility (public recreational spaces such as community centers parks and sports grounds) is linked to decrease in active participation in exercise and normal leisure related activity such as walking, grocery shopping, gardening etc. despite counteracting measures taken to increase overall activity at home by offering online "at home physical activity classes" through various social media platforms, present results indicate that it has not been possible for j o u r n a l p r e -p r o o f individuals to adequately maintain their normal activity patterns with suggested home activities [13] . the decline in time spent in engaging in physical activity was accompanied by increased screen and sitting time. a substantial increment in the number of hours (4-5 hours) spent in front of the screen for the recreational or work purpose was seen in our study as well. covid-19 has limited day-to-day social engagements such as workplace interactions, participation in recreational activities, socializing and eating out which might lead to an increase in mental health distress. we also found out that one-fourth of the participants reported an increase in stress and anxiety level by one unit due to fear of getting infected by coronavirus, boredom, loneliness and financial loss at work. similar findings were reported by a number of studies showing moderate levels of quarantine induced stress and anxiety in indian adults with more than 80% adults preoccupied with fearful thoughts of getting coronavirus infection [14, 15] . the study also highlights the association of demographic variables with changes in lifestyle related behaviors due to covid-19 pandemic. in our study, a significant improvement was observed in overall eating behavior in the younger age group (<30 years). similar findings were reported in an italian survey, where the highest compliance to a traditional mediterranean diet (high in antioxidants from fruits and vegetables and mufa from olive oil and fish) was exhibited by younger people (18-30 years) [12] . eating behavior also significantly improved in upper socio-economic status but conversely the physical activity decreased. despite reduction in food availability, the upper strata of society had the economic means and time to procure and maintain access to healthier ingredients (such as fresh fruits and vegetables, nuts, oilseed, milk and products) and transform them into healthy meals. it has been already seen in china that level of lockdown and socio-economic status defined level of physical activity [16] . the involvement of lower strata in delivering essential services to restore economic means for surviving the pandemic might have led to an increased daily overall activity level. we also found out that changes in these lifestyle related behaviors also led to weight gain in onethird of the sample. since individuals with obesity and associated metabolic comorbidities such as diabetes and cardiometabolic disease are more prone to getting covid-19 infection [17, 18] , the control on adaptation of negative lifestyle related behaviors becomes a crucial preventive step in containing the spread [19] . the findings also indicate that decline in physical activity and j o u r n a l p r e -p r o o f increase in stress outweighed marginal improvement in dietary behavior, which might have led to a positive calorie balance, further leading to weight gain in the sample. the results from this study are concurrent with western literature in establishing that adaptation of negative lifestyle related behaviors to abate coronavirus infection are one of the potential consequences of covid-19 pandemic. to our knowledge, this is the first study in india to understand the extent of changes in lifestyle related behaviors and its underlying covid specific reasons, in order to counteract these changes for maintenance of optimal health status at individual and community level. human behaviour is a product of a combination of environmental, cultural, economic and social variables, since all these variables are known to vary with changing situations during covid-19 pandemic, there is a need for further research to identify the correlated that has maximum impact on these behaviors to develop effective public health promotion strategies. the increase in usage of information and communication technology during pandemic should be used to our advantage in devising 'one stop lifestyle applications' to disseminate knowledge, change pandemic driven attitude and provide specific action points to manage healthy lifestyle habits amidst pandemic. the information on demographic variation in lifestyle practice during covid-19 can help to devise user-friendly behavioral support interventions using fitness applications, video streaming and motivation support. this is the first pan-india study which aimed to recruit a representative sample for collection of data using a pre-validated questionnaire to study the impact of covid-19 on lifestyle related behaviors. some limitations of the study are possibilities of reporting bias, due to e-survey and telephonic survey, validity of answers is a general problem of online surveys, differential approach described in the methods section. in conclusion, the results of the study indicate a mixed effect of the preventive measures enforced/adopted to control coronavirus on the lifestyle related behavior with a significant improvement in regular meal consumption pattern and healthy eating behavior and reduction in unhealthy food intake as positive indicators and significant reduction in physical activity and increase in sitting time, and screen time and stress as negative indicator. even though there were improvements in eating behaviors, but its affect was limited. the negative effect of lifestyle j o u r n a l p r e -p r o o f related behaviors would outweigh the positive effect of one unit correction in eating behavior, which would lead to higher incidents of weight gain and associated metabolic complications. these observations have potential implications that could aid the development of physical activity and nutritional recommendations to maintain health during the covid-19 pandemic. values are presented as mean ± standard deviation or number (frequency %). obesity risk during collective quarantine for the covid-19 epidemic dietary and lifestyle changes during covid-19 and the subsequent lockdowns among polish adults: a cross-sectional online survey plifecovid-19 study global physical activity levels:surveillance progress, pitfalls, and prospects a short questionnaire to assess changes in lifestyle-related behaviour during covid 19 pandemic impact of lockdown due to covid-19 outbreak : lifestyle changes and public health concerns in india covid-19 related home confinement in adults: weight gain risks and opportunities understanding meal patterns: definitions, methodology and impact on nutrient intake and diet quality effects of meal frequency on weight loss and body composition: a meta-analysis impact of sedentarism due to the covid-19 home confinement on neuromuscular, cardiovascular and metabolic health: physiological and pathophysiological implications and recommendations for physical and nutritional countermeasures effects of covid-19 home confinement on eating behaviour and physical activity: results of the eclb-covid19 international online survey food reward and food choice. an inquiry through the liking and wanting model eating habits and lifestyle changes during covid-19 lockdown: an italian survey traininginhome -home-based training during covid-19 (sars-cov2) pandemic: physical exercise and behavior-based approach depression, anxiety and stress among indians in times of covid-19 lockdown. community ment health j 2020 study of knowledge, attitude, anxiety & perceived mental healthcare need in indian population during covid-19 pandemic mental health outcomes of quarantine and isolation for infection prevention: a systematic umbrella review of the global evidence effects of nationwide lockdown during covid-19 epidemic on lifestyle and other medical issues of patients with type 2 diabetes in north india is excess weight a risk factor for the development of covid 19 infection? a preliminary report from india effects of covid-19 lockdown on lifestyle behaviors in children with obesity living in verona, italy: a longitudinal study key: cord-318528-yc0jw3s1 authors: romero-blanco, cristina; rodríguez-almagro, julián; onieva-zafra, maría dolores; parra-fernández, maría laura; prado-laguna, maría del carmen; hernández-martínez, antonio title: physical activity and sedentary lifestyle in university students: changes during confinement due to the covid-19 pandemic date: 2020-09-09 journal: int j environ res public health doi: 10.3390/ijerph17186567 sha: doc_id: 318528 cord_uid: yc0jw3s1 regular physical activity is related to many factors in a university student’s environment. the coronavirus pandemic and the resulting lockdown have restricted many elements of our environment. the aim of this study was to evaluate students’ physical activity and sedentary behaviour at two points in time: before and during the coronavirus lockdown. as a secondary aim, we also wanted to look at changes resulting from other factors (alcohol, tobacco, diet, stages of change, symptoms of anxiety/depression and sociodemographic characteristics). we conducted an observational, cross-sectional, pre-post study with two cut-off points. two hundred and thirteen students took part in the study. the main dependent variables were physical activity and sitting time, measured using the international physical activity questionnaire—short form (ipaq-sf). parametric and non-parametric tests were used for paired and unpaired data, as well as group-stratified analysis. during lockdown, both weekly physical activity (md: −159.87; ci: −100.44, −219.31) and weekly sitting time increased (md: −106.76; ci: −71.85, −141.67). in the group analysis, differences were observed in relation to gender, year of study, bmi, alcohol consumption, tobacco use, symptoms of anxiety/depression, mediterranean diet, living situation and stage of change. the results showed an increase in both physical activity and sitting time globally and by group. a healthy lifestyle should be promoted among all ages, but the earlier a habit is formed, the more likely it is to become rooted [1] . regular physical activity is one of the most effective ways of preventing premature death [2, 3] . the world health organization (who) recommends at least 150 min of moderate physical activity, 75 min of vigorous activity, or a combination of the two, per week [4] . independently of the physical activity carried out, it is important to assess sedentary behaviour (sb) as this is related to increased morbidity and cardiovascular risk factors [5] . by 2030, the who aims to reduce the prevalence of physical inactivity by 15% worldwide [6] . in spain, the amount of physical activity carried out by university students is low [7] and is in many cases linked to other healthy habits such as eating fruit and not smoking [8] . meanwhile, sedentary behaviour is a health problem in the child and youth population, which is aggravated with age [9] . in university students, sitting time can exceed 9 h a day [10] . it is known that individual factors such as age, sex and health status affect the physical activity that individuals do [11] . other factors associated with physical activity are motivation, lack of time and aspects related to body image or physical appearance [12] ; some of the beneficial effects of physical activity are reduced anxiety and depression [13, 14] . however, there are several factors that come into play throughout an individual's lifetime that can either facilitate or impede a behaviour, with the transition from secondary education to university being a decisive moment [15] . it is at this time that young adults form their behavioural habits, so the role of healthy universities and the healthy habits they acquire at this stage are fundamental in maintaining this behaviour in the years to come [16] . when it comes to making physical activity a regular habit, the elements that may be related have been studied in depth [17] . ecological models are considered one of the most significant theoretical approaches when it comes to analysing habit formation [18] . these models establish that in addition to individual factors, social and environmental factors are determinant in forming and maintaining physical activity habits [19] . the covid-19 pandemic led to the population being confined to their homes [20] . in spain, from march to april 2020, there was a prohibition on going outside to engage in sporting or social activities. during this period, elements of the built environment and other factors related to individuals' environments were restricted due to the state of alarm. this created a valuable opportunity to assess physical activity without taking these factors into account. experts' recommendations to prevent sedentary behaviour during lockdown included taking active breaks, getting up and walking around the house, and doing online workouts [21] . however, during the pandemic, an overall negative effect on physical activity intensity was observed, as well as a rise in the consumption of less healthy food and a 28.6% increase in sedentary behaviour [22] . a reduction in physical activity was also observed in university students [23] , along with increased levels of anxiety among 18-to 34-year-olds [24] . spanish university students had to continue attending classes online, and their social lives were limited due to the prohibition on going outside. during lockdown, physical activity could have been an opportunity to pass the time, or, conversely, sedentary behaviour could have increased. the other characteristics of each individual (gender, motivation, eating habits, mental state etc.) could have either facilitated or interfered with the decision to exercise. the hypothesis put forward was that students' sedentary behaviour would have increased during lockdown since they were confined to their homes, and that their physical activity would have decreased since they could not go outside to exercise. in this study, we aimed to analyse the physical activity university students did before and during lockdown. to broaden our approach, as a secondary aim, we also wanted to look at changes in physical activity and sedentary behaviour resulting from other factors such as alcohol and tobacco consumption, adherence to a mediterranean diet, motivation, symptoms of anxiety/depression and sociodemographic characteristics. we aimed to evaluate whether there were any differences when certain factors affecting individuals' environments were restricted. this was an observational, cross-sectional, pre-post study on health sciences students, with two cut-off points. the first cut-off point was between 15 and 30 january 2020, prior to the state of alarm being put in place, and the second sample point was between 1 and 15 april 2020. this study received the approval of the ethics and clinical research committee of ciudad real, in spain, with protocol number (c-291, 11/2019). this study was carried out within the context of another study that we conducted on healthy habits and lifestyles, with an estimated follow-up period of 9 months. due to the state of alarm and lockdown, recruitment of subjects was temporarily suspended and a decision was made to study the impact of lockdown on the population already participating. there were no exclusion criteria, other than failure to fully complete the questionnaire. to estimate the sample considering a bilateral hypothesis, the following criteria were used: variance in the pre-lockdown control group of 33,929.60, obtained using the total minutes of physical activity [25] , a beta risk of 20% (power = 80%), a confidence level of 95% and a clinically important difference of 60 min with respect to the control group. it was therefore estimated that a minimum of 148 study subjects would be needed. considering a missing values ratio of 20%, the resulting sample size would be 185 subjects. the students invited to take part were first-to fourth-year students who agreed to respond to the questionnaire at both time points. the questionnaires were administered during the second university semester. the first data collection point was two weeks after the end of the exam period, while the second data collection point was four weeks into lockdown. at the second data collection point, students could not leave their homes except for essential purposes such as buying food or going to hospital. outdoor exercise was prohibited across spain; anyone breaching the rules faced a 600 euro fine. during lockdown, university classes continued online with the same schedule as usual. the university provided internet access or technological devices to any students who requested them so that they could continue attending classes. online classes did not contain any recommendations for students to carry out physical activity. an ad hoc self-administered questionnaire was used, collecting sociodemographic information such as sex, age, weight, height, place of residence during the academic year, smoking habits (yes/no and number of cigarettes per day) and alcohol consumption (yes/no and number of drinks per week). for perceived health status and the existence of problems with anxiety/depression, the euroqol 5d (eq-5d) questionnaire was used [26] . to assess adherence to the mediterranean diet, the predimed questionnaire [27] was used, which uses 14 questions to assess the frequency of food consumption and eating habits. each question has a possible score of 0 or 1. the result allows classification into low adherence or high adherence. stages of change (soc) in physical activity were assessed using prochaska and diclemente's transtheoretical model (ttm) [28] . five stages of motivation for change were evaluated: pre-contemplation (i don't exercise and i don't intend to), contemplation (i don't exercise, but i'd like to), preparation (i exercise sometimes), action (i have been regularly exercising for less than 6 months) and maintenance (i have been regularly exercising for more than 6 months). physical activity was measured using the international physical activity questionnaire-short form (ipaq-sf), which contains 7 questions [29] . the questionnaire was used to obtain the total minutes of physical activity per week and sitting time per day. first, descriptive statistical analysis was performed using absolute and relative frequencies for categorical variables and mean with standard deviation (sd) for the quantitative variables. next, bivariate analysis was performed on the whole sample for paired data between weekly minutes of physical activity for the two sample points (pre-lockdown and lockdown). we used the kolmogorov-smirnov test to verify the normality of the quantitative variables. since there were variables that were not normally distributed, we then used the non-parametric wilcoxon signed-rank test. we also used the parametric student-fisher t-test to evaluate whether there were statistical differences in some comparisons and to obtain an approximation of the differences found. finally, the same analyses were performed again, but this time stratified for different sub-groups. mean differences (md) were obtained with a confidence interval of 95% (ci). all calculations were done using the program spss v24.0 (ibm corp, new york, ny, usa). two hundred and thirteen health sciences students participated in this study. the mean age was 20.5 years (sd = 4.56). of the participants, 80.8% (172) were women, 76.5% (163) were normal weight and 9.9% (21) were smokers. the rest of the demographic characteristics and health parameters are shown in table 1 . then, the results of the ipaq questionnaire were analysed: days and minutes of physical activity per week, as well as time spent sitting per week at both time points studied ( table 2) . we observed a significant increase in the number of days on which students engaged in physical activity, both vigorous we then analysed physical activity by group (table 3 ). when we looked at the differences in average minutes of physical activity, all groups analysed spent more time doing physical activity during lockdown (although not all of them significantly). groups that showed significant differences were women; first, second and third year of study; normal or low bmi; and those who did not eat a mediterranean diet. average physical activity time reduced during lockdown for participants in the pre-contemplation (md: 37.50; 95% ci: −115. 33, 190.33) and contemplation (md: 31.08; 95%ci: −15.87, 78.03) stages. in other words, they spent less time on physical activity, although this difference was not significant. conversely, for those in the preparation (md: −75.59; 95%ci: −0.92, −150.25) and action (md: 322.69; 95%ci: −214.84, −430.55) stages, significant differences (p < 0.05) were observed. in the rest of the groups analysed, statistically significant differences were observed between the two time points, except for men, final-year students, those that were overweight or obese and those that ate a mediterranean diet. finally, the analysis by group (table 4 ) showed significant differences (p < 0.05) in sitting time before and during lockdown in all groups except first-year students, those that were overweight or obese, smokers and those in the pre-contemplation stage. sitting time increased in all groups of the variables gender, alcohol, symptoms of anxiety/depression and mediterranean diet. it also increased in the following groups: second, third and fourth year of study; normal and underweight bmi; non-smokers; those living in a university residence, shared apartment or with family; and those in the contemplation, preparation, action and maintenance stages. this study aimed to evaluate physical activity and sedentary behaviour in health sciences students before and during the lockdown. at the first time point, students were in their normal study environment, while at the second, their social and environmental setting was limited due to lockdown. the results showed changes in physical activity and sedentary behaviour patterns both globally and by group. overall, students spent more time doing physical activity and spent more time sitting when their usual environment was limited. in the analysis by group, minutes of physical activity increased significantly during lockdown among the following groups: women; all years of study except final year; normal or low bmi; those who did not eat a mediterranean diet; and those in the preparation or action stage of change. sitting time increased in all groups of the variables gender, alcohol, symptoms of anxiety/depression and mediterranean diet. the groups that did not experience differences were: first year of study, overweight or obese, smokers and those in the pre-contemplation stage. these four groups spent the most time sitting at the first data collection point when compared with the rest of their cohort; in other words, sedentary behaviour was already high before lockdown and there were no significant differences at the second data collection point. some researchers believed that lockdown would cause inactivity and an increase in sedentary behaviour and that measures would need to be taken to prevent these effects [30] . in fact, during lockdown, people modified their lifestyles, with an increase in sitting time due to people spending more time at home, and there was also a reduction in the amount of time spent on physical activity [22] . in our study, the initial hypothesis was partially confirmed: there was an increase in sitting time, but unexpectedly, there was also an increase in both the amount of time spent doing physical activity and the number of days on which participants were active. we expected to find an increase in sitting time due to the restrictions on movement; however, we also thought that the increase in screen time would reduce physical activity time, since in previous studies conducted in the spanish university population, more screen time was associated with higher inactivity levels [31] . we do not know the exact reasons why physical activity increased, and we do not know if the effects on physical activity habits would have been maintained if the lockdown had gone on for longer. the environment in which students live affects their sedentary behaviour patterns [32] , and it seems that the characteristics of health sciences students' environments do not facilitate physical activity. rather than being an obstacle, restricted social relations and not having access to the built environment in their community increased the number of days and minutes students spent doing physical activity. in the case of health sciences students, another factor to consider is that their training in promoting healthy habits may have influenced their decision to exercise at home. no changes in physical activity were found in men. perhaps men and women had different motivations and the environment influences one gender more strongly. in previous studies on motives for physical activity by gender [33] , some variables that motivated men but not women were elements related to the environment, such as competition or social recognition, while weight control was the main motivation for women. in our study, women accounted for more than 80% of the sample, so the lack of results may also be due to the fact that there were fewer male participants. the effect of the built environment is yet to be determined for those with a high bmi [34] . the data in this study show that in overweight or obese students, there were no changes in time spent doing physical activity or sitting time. as we have seen, healthy habits that are ingrained in the population are not affected by the lockdown: this is the case of the mediterranean diet [35] . in this study, we observed that students that ate a mediterranean diet spent more time doing physical activity and that their physical activity patterns did not change significantly. this suggests that those that lead a healthy lifestyle pay attention to both diet and exercise and persist with their habits regardless of the environment. conversely, those with unhealthy habits stick to them and experience no changes during lockdown. this is the case for smoking and sedentary behaviour. grouping of healthy and non-healthy factors is habitual in university students [8, 25] : those that are more sedentary are also more likely to smoke or spend a lot of time watching screens, while those that exercise regularly tend to eat more fruit and vegetables and drink less alcohol. contrary to what we expected, smokers did spend more time doing physical activity during lockdown. it would be interesting to investigate the reasons for this. in our sample of the population, the percentage of smokers was very low, and the number of cigarettes smoked per day was also low, so we believe more research is needed in a sample with more smokers. in our results, we also found differences based on year of study. among final-year students, physical activity did not vary significantly. this group also spent the least time doing physical activity at both time points analysed. in their meta-analysis, keating et al. indicate that with regard to year of study, the majority of studies find no differences in physical activity, but that some studies suggest that higher years of study are less active [36] . as for sedentary behaviour, it was observed that first-year students spent more time sitting and that lockdown did not bring about any significant changes. some studies, contrary to the findings of our study, observed that students in higher years of study were more sedentary due to a higher workload [10] . in health sciences students, most of the theoretical workload is in the first year, while in their final year students spend most of their time on placement. another possible factor could be that first-year students might have practiced sport in secondary school and kept up the habit. it would have been interesting to ask students about their sports histories. in this study, we evaluated stages of change, one of the central concepts of the transtheoretical model of change. this model was initially used to treat tobacco and alcohol problems, but it was later adapted to other aspects of health such as physical activity and sedentary behaviour [37] [38] [39] . the analysis of the stages of change and how they affected the participants was very interesting. participants in the first two stages did not experience any changes, and neither did those in the last stage. the behaviour of participants that exercised as part of their routine remained practically the same, as did the behavior of those that did not do any exercise. however, for those that were motivated but had not yet made exercise a regular habit, lockdown was a good opportunity to increase their dedication. in line with these findings, di renzo et al. [35] observed in a recent study that lockdown increased activity among people that did sport occasionally because they had more time at home, but those that did not do any exercise did not use the situation as an opportunity to start. overall, the results show that minutes of physical activity increased, as did minutes of sitting time. although the results during lockdown are positive in terms of physical activity, it is necessary to recognise that this population might suffer from health issues in the future due to an increase in sedentary behaviour. it would be interesting to find out what the reasons were for students having this behaviour. perhaps they realised that their sitting time increased (they were not walking to class, walking to their car, going shopping, standing up, going to their jobs etc.) and compensated for this with some high-intensity exercise. another aspect that could have affected the results is that the students were involved in the health sciences field, so they may have been more prone to exercising during the pandemic than students in other majors such as engineering or literature. this is why we cannot exclusively consider the limitation of the environment during lockdown to be the cause of the changes in physical activity and sedentary behaviour. it would be interesting to continue studying the elements related to university students' physical activity/sedentary behaviour and their surroundings in order to plan strategies that promote an increase in physical activity levels in this group. our study has various limitations that should be considered. firstly, it is an observational study and all study subjects volunteered to participate in the questionnaire, so there may be a selection bias. secondly, we did not measure whether there was any risk of exposure to covid-19 infection, a factor that could have influenced our assessment of physical activity and sedentary behaviour. another limitation is the use of a self-administered questionnaire to evaluate physical activity and sedentary behaviour. it would have been more interesting to perform a real assessment of physical activity using accelerometry and also investigate their sports history. this could be a future line of research. finally, the lack of significance in some of the strata analysed could be due to a lack of statistical power because of the low number of subjects in some groups. furthermore, we do not know if these changes in physical activity would have been maintained if lockdown had gone on longer. as for the strengths, this is the first study to look at physical activity and sedentary behaviour in university students studying health sciences both before and during lockdown. in this study, we observed the behaviour of health sciences students when deprived of their usual social and community environment. participants spent more time doing physical activity and also spent more time sitting. university students' social environment may be a barrier to building an exercise habit, especially among women, and motivation seems to have a significant bearing on whether university students engage in physical activity. more efforts should be made to create strategies that motivate students to lead a healthy lifestyle in all aspects (diet, avoiding harmful substances, mental health etc.), with a particular emphasis on engaging in physical activity and reducing sitting time. programs and policies that promote positive youth development and prevent risky behaviors: an international perspective health benefits of physical activity: the evidence health benefits of physical activity: a systematic review of current systematic reviews world health organization. global recommendations on physical activity for health sedentary behavior and cardiovascular morbidity and mortality: a science advisory from the american heart association world health organization. global action plan on physical activity 2018-2030: more active people for a 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consumption, physical activity and diet quality the spanish version of euroqol: a description and its applications a 14-item mediterranean diet assessment tool and obesity indexes among high-risk subjects: the predimed trial stages and processes of selfchange of smoking:toward an integrative model of change validation of three short physical activity questionnaires with accelerometers among university students in spain how to deal with covid-19 epidemic-related lockdown physical inactivity and sedentary increase in youth? adaptation of anses' benchmarks cluster analysis of health-related lifestyles in university students neighborhood built environment and socioeconomic status are associated with active commuting and sedentary behavior, but not with leisure-time physical activity, in university students college students' motivation for physical activity: differentiating men's and women's motives for sport participation and exercise role of built environments in physical activity, obesity, and cardiovascular disease eating habits and lifestyle changes during covid-19 lockdown: an italian survey a meta-analysis of college students' physical activity behaviors role of counseling to promote adherence in healthy lifestyle medicine: strategies to improve exercise adherence and enhance physical activity application of the transtheoretical model to sedentary behaviors and its association with physical activity status levels of physical activity, motivation and barriers to participation in university students funding: this research received no external funding. the authors declare no conflict of interest. key: cord-016362-d3cpy37g authors: orhan, ilkay; özcelik, berrin; şener, bilge title: antiviral and antimicrobial evaluation of some heterocyclic compounds from turkish plants date: 2007-08-01 journal: bioactive heterocycles v doi: 10.1007/7081_2007_072 sha: doc_id: 16362 cord_uid: d3cpy37g antibiotic resistance has become a problem since the discovery of antibiotics. not long after the introduction of penicillin, staphylococcus aureus, which can be also transmitted to humans via milk and milk products, began developing penicillin-resistant strains. therefore, one approach that has been used for the discovery of new antimicrobial agents from natural sources is based on the evaluation of traditional plant extracts. natural products have played a pivotal role in antibiotic drug innovation and include aminoglycosides, cephalosporins, macrolides, cycloserine, novobiocin, and lipoproteins. however, only a few antiviral agents are available on the market. to this purpose, we have screened a great number of herbal extracts along with some pure natural substances and obtained interesting findings. this chapter covers the results of our rigorous search for new antiviral and antimicrobial alternative compounds from a number of turkish plants. since their discovery during the twentieth century, antimicrobial agents (antibiotics and related medicinal drugs) have substantially reduced the threat posed by infectious diseases. on the other hand, antibiotic resistance can be defined as the ability of any microorganism to withstand the effects of an antibiotic, which is a specific type of drug resistance and evolves naturally via natural selection through random mutation [1, 2] . the antibiotic action is an environmental pressure; those bacteria that have a mutation allowing them to survive will live on to reproduce. they will then pass this trait to their offspring, which will be a fully resistant generation [3, 4] . without doubt, antibiotic resistance is a global issue. because of cross-continental travel of both humans and goods, antibiotic-resistant bacteria are spread from one country to another. therefore, antibiotic resistance has been called one of the world's most pressing public health problems. much evidence supports the view that the total consumption of antimicrobials is the critical factor in selecting resistance. paradoxically, underuse through lack of access, inadequate dosing, poor adherence, and substandard antimicrobials may play as an important role as overuse [5, 6] . since misuse of antibiotics jeopardizes the usefulness of essential drugs, decreasing inappropriate antibiotic use is the ideal way to control resistance [7] . natural selection of penicillin-resistant strains in a bacterium known as staphylococcus aureus began soon after penicillin was introduced in the 1940s. recently more hospital-acquired infections are becoming resistant to the most powerful antibiotics available, such as vancomycin, which emerged in the united states in 2002, presenting physicians and patients with a serious problem [8] . a number of cases of community-associated methycillin-resistant s. aureus (mrsa) have also been reported, including cases in patients without established risk factors [9] . modern medical science and practice have something of an armory of effective tools, ranging from antiseptics and anesthetics to vaccines and antibiotics. however, one field has been weak in finding drugs to deal with viral infections, although viral diseases have affected humans many centuries. the emergence of antivirals is the product of a greatly expanded knowledge of the genetic and molecular function of organisms, allowing biomedical researchers to understand the structure and function of viruses. on the other hand, herbal medicine is the oldest form of healthcare known to mankind and has been used by all cultures throughout history. the world health organization (who) estimates that 4 billion people, 80% of the world population, presently use plants for some aspect of primary health care. who also notes that of 119 plant-derived pharmaceutical medicines, about 74% are used in modern medicine in ways that correlate directly with their traditional uses as plant medicines by native cultures. in our ongoing study on the plant extracts and their pure compounds from turkish medicinal plants, we have so far screened a number of plant extracts and pure components for their antimicrobial and antiviral activities. in this chapter, we intend to cover the recent results obtained from our antimicrobial and antiviral studies on heterocyclic compounds isolated from several turkish medicinal plants and marine organisms. although biodiversity in terrestrial environments is extraordinary, oceans covering more than 70% of our planet represent a greater diversity of life. a small number of marine plants, animals, and microbes have already yielded over 12 000 novel compounds [10] . among them, a great number of substances of marine origin have been reported to possess antimicrobial activity such as loloatins a-d, myticins a and b, psammaplin a, etc., which have been covered in several excellent reviews [10] [11] [12] . in our previous study, ten terpene-type compounds, which we isolated from the marine sponges ircinia spinulosa and spongia officinalis of the aegean sea collection, were assayed against the american-type culture collection (atcc) strains of bacillus subtilis (6633), s. aureus (6536), pseudomonas aeruginosa (9027), and escherichia coli (8739) by the disk diffusion method [13] . the results were evaluated by comparing the inhibition zones of the compounds, namely, furospinulosin-1, furospongin-1, 2-(hexaprenylmethyl)-2-methylchromenol, heptaprenyl-p-quinol, 12-epi-deoxoscalarin, 1,4,44-trihydroxy-2-octa-prenylbenzene, demethylfurospongin-4, 4-hydroxy-3-octaprenylbenzoic acid, 4-hydroxy-3-tetraprenylacetic acid, and 11-β-acetoxy-12-en-16-one. we found that furospinulosin-1, furospongin-1, 2-(hexaprenylmethyl)-2-methylchromenol, and heptaprenyl-p-quinol did not exhibit any inhibition against those bacterium strains, whereas 12-epi-deoxoscalarin (1) exerted a weak activity against b. subtilis and s. aureus, causing inhibition zones of 12 and 11 mm in diameter, respectively (fig. 1 ). demethylfurospongin-4 (2), 4-hydroxy-3-tetraprenylacetic acid (3), and 11-β-acetoxy-12-en-16-one (4) were also active against gram-positive bacteria (fig. 1 ). among them, 4-hydroxy-3-tetraprenylacetic acid (3) was the most effective causing 20 mm of inhibition zone (fig. 1) . none of the compounds tested had an ability to inhibit e. coli. owing to scarcity of the compounds, only one concentration (0.5 mg/disk) could be tested. in conclusion, we suggested that this assay should be better with higher yield, if repeated. in a similar study reported previously, 23 hydroquinone and quinone derivatives from the sponge ircinia spinulosa were tested for their antibacterial activity, and relevant structure-activity relationships (sar) were established [14] . as a consequence, sar studies indicated that the optimum length of side chain in the compounds for antibacterial activity should be 5-15 carbon atoms, which is in accordance with our most effective compound, 4-hydroxy-3-tetraprenylacetic acid (3). besides, it was reported that long-chain alcohols exert higher antimicrobial activity compared to the corresponding acids and aldehydes [15] . similarly, a relationship between antibacterial activity and the structure of aliphatic alcohols was described, which suggested that maximum activity against s. aureus might be depend on the number of carbon atoms in hydrophobic chain. this should be less than 12, but as close to 12 as possible [16] . however, according to the study of inoue et al., this finding did not support the anti-stapylococcus effect of the aliphatic terpene alcohols, farnesol, nerolidol, and plaunotol, which may result from configuration of functional groups and double bonds that affected activity [17] . therefore, in that study, it was concluded that anti-stapylococcus activity depends not only on aliphatic side chains, but also on the configurations of functional groups and double bonds. possibly, the difference observed in the antibacterial effect of our compounds might be due to this reason as well. flavonoids are a group of polyphenolic compounds ubiquitous in many plants, in which they occur as the free forms, glycosides, as well as as methylated derivatives. in addition to their diverse biological activities, there is an increasing interest in flavonoids due to their anti-infective properties [18] . for instance, the flavonoids quercetin and kaempferol, as well as the flavonoid glycosides rutin and isoquercitrin, were reported to have antibacterial and antifungal activities [19] . quercetin and kaempferol are known to be the most common flavonols present in many plants, and occur in different glycosidic forms. in many studies, they or their various glycosides have been proved to possess antimicrobial activity or, in other words, the antimicrobial activity of plant extracts (e.g., rubus ulmifolius, combretum erythrophyllum, morus alba, trollius chinensis, and propolis) has been attributed to quercetin and kaempferol [20] [21] [22] [23] [24] [25] . in one of our recent studies, we examined antimicrobial and antiviral activities of four flavonoid derivatives, namely, scandenone (5), tiliroside (6), quercetin-3,7-o-α-l-dirhamnoside (7), and kaempferol 3,7-o-α-ldirhamnoside (8) as shown in fig. 2 . these were tested against e. coli, p. aeruginosa, proteus mirabilis, klebsiella pneumoniae, acinetobacter baumannii, s. aureus, b. subtilis, and enterococcus faecalis, as well as the fungus candida albicans by the microdilution method [26] . in addition, both dna virus herpes simplex (hsv) and rna virus parainfluenza (pi-3) were employed for antiviral assessment of the compounds using madin-darby bovine kidney (mdbk) and vero cell lines. all four compounds were found to be most active against s. aureus and e. faecalis, with a minimum inhibitory concentration (mic) of 0.5 µg/ml, followed by e. coli (2 µg/ml), k. pneumoniae (4 µg/ml), a. baumannii, and b. subtilis (8 µg/ml). p. mirabilis and p. aeruginosa were the most resistant bacteria against the compounds (16 and 32 µg/ml, respectively). notably, antibacterial activity of the compounds was as potent as ampicillin (amp) and oflaxocin (ofx) towards s. aureus and e. faecalis. these compounds also possessed quite remarkable antifungal activity against c. albicans, as much as ketocanozole (ket) (1 µg/ml). as shown in table 1 , none of the compounds had the ability to inhibit hsv, while only quercetin-3,7-o-α-l-dirhamnoside had inhibitory activity against pi-3 in the range 8-32 µg/ml of maximum and minimum cytopathogenic effect (cpe) inhibitory concentrations, respectively. the inhibitory concentration range of this compound is on a vast scale, which resembles that of oseltamivir (32 to < 0.25 µg/ml). besides, its maximum non-toxic concentration (mntc) (64 µg/ml) was observed to be better than oseltamivir (32 µg/ml). one of the undisputed functions of flavonoids and related polyphenols is their role in protecting plants against microbial invasion, which accumulate phytoalexins in response to microbial attack plants. moreover, it is evident that a structure-activity relationship exists between the various flavonoids and their antimicrobial activity in most cases. a large number of antimicrobial flavonoids have been reviewed brilliantly and their sars discussed [27] [28] [29] [30] [31] [32] . the majority of antifungal flavonoids have been observed to have either isoflavonoid, flavan, or flavanone structures such as maackiain, mucronulatol, luteolin 7-(2 -sulfatoglucoside), etc., which is consistent with our data on flavonoids. accordingly, the presence of a phenolic group in the flavonoid structure suggests that it is necessary for antimicrobial activity. interestingly, increasing the number of hydroxyl, methoxyl, or glycosyl substituents resulted in the steady loss of antifungal effect of the flavonoids [33] . in the review of bylka et al. [34] , it was suggested that the antibacterial effect towards gram-negative bacteria is higher with flavones, while flavonoids containing two or three hydroxy groups in rings a and b are more active in inhibition of gram-positive bacteria. however, in our study, all four flavonoid derivatives, consisting of one prenylated isoflavone and three flavonol glycosides, exhibited an equal strength of antibacterial and antifungal activities, independent of their structural substitutions. recently, flavonoids have been investigated from the viewpoint of their antiviral effect, particularly against the human immunodeficiency virus (hiv), the causative agent of acquired immonodeficiency syndrome (aids). among them, quercetin has been shown to be effective against divergent virus types by many researchers, which supports our data on quercetin-3,7-oα-l-dirhamnoside [26] . in one of the earliest studies, oral application of quercetin in mice was found to display a protective effect towards intraperitoneal encephalomyocarditis, mengo m,l and mengo m virus infections, but not against intracerebral challenge with mengo m virus. it was not virucidal and did not interfere with mengo virus replication in l cells [35] . the potentiative interaction of quercetin with murine α/β interferon in mice against mengo virus infection [36] was also proved. moreover, quercetin was reported to greatly enhance the antiviral effect of tumor necrosis factor (tnf) that produces a dose-dependent inhibition of vesicular stomatitis virus, encephalomyocarditis virus, and hsv type-1 replication in wish cells [37] . in another study, the effect of different substituents of quercetin and luteolin on the ability to inhibit the hsv type-1 replication in rk-13 cells was studied [38] . in conclusion, our results demonstrated that scandenone, tiliroside, quercetin-3,7-o-α-l-dirhamnoside, and kaempferol-3,7-o-α-l-dirhamnoside possessed severe antibacterial and antifungal activities, whereas only quercetin-3,7-o-α-l-dirhamnoside exerted noticeable anti-pi-3 activity. the genus consolida, aconitum, and delphinium (ranunculaceae) are wellknown to be rich in diterpene alkaloids, which possess a diverse range of biological activities. these plants have also been the cause of poisonings, which primarily occur in cattle as well as human beings, due to toxicity of their alkaloids. in one of our recent studies, five diterpenoid-derivative alkaloids, lycoctonine (9), 18-o-methyllycoctonine (10), delcosine (11), 14acetyldelcosine (12), and 14-acetylbrowniine (13) (as shown in fig. 3) were screened for their antibacterial, antifungal, and antiviral activities [39] . once more, hsv and pi-3 were employed for antiviral assessment of the compounds using mdbk and vero cell lines. their mntc and cpe values were determined using acyclovir and oseltamivir as the references. besides antibacterial and antifungal activities, the alkaloids were tested against e. coli, p. aeruginosa, p. mirabilis, k. pneumoniae, a. baumannii, s. aureus, and b. subtilis, as well as the fungus c. albicans by the microdilution method as compared to the references amp, ofx, and ket. the results pointed out that these alkaloids possessed the highest antibacterial activity against k. pneumoniae and a. baumannii at 8 µg/ml concentration (table 2) , whereas they were moderately active to the rest of the bacteria. however, all the alkaloids tested were highly effective against c. albicans in a comparable manner to ket in the antifungal screening. conversely, a selective inhibition was observed towards pi-3 virus by these alkaloids, while they were entirely unsuccessful on inhibition of hsv (table 3) . pi-3 inhibitory activity of the alkaloids was fairly analogous to that of oseltamivir, ranging between 8-32 µg/ml as minimum and maximum inhibitory concentrations for the cpe. our results showed that the alkaloids possessed rather high antifungal activity against c. albicans and a compelling antibacterial effect only against k. pneumoniae and a. baumannii, while they exerted a strong inhibition against pi-3. even though much is already known about the toxicity of diterpene alkaloids that contribute to the toxicity of consolida, delphinium, and aconitium species, no antiviral study has been so far reported on this type of alkaloids. therefore, no sar studies have been encountered by us on the antiviral or antimicrobial activities of these alkaloids. however, a quantitative sar analysis performed on a number of diterpene alkaloids isolated from an aconitum sp. indicated that biological activity of these alkaloids may be related to their toxicity rather than to a specific pharmacological action [40] . in a current study on 43 norditerpenoid alkaloids from consolida, delphinium, and aconitum species against several tumor cell lines, lycoctonine and browniine were 312 i. orhan et al. found to be active among those screened [41] . in contrast to this data, lycoctonine and 14-acetyl derivative of browniine in our study showed a lesser amount of cytotoxicity on mdbk and vero cell lines at 64 µg/ml. gonzales-coloma et al. studied antifeedant activity and toxicity of some diterpene alkaloids (15-acetylcardiopetamine, cardiopetamine along with its amino alcohol, the β, γ unsaturated ketone, and the acetylated ketone derivatives) from delphinium sp. on the insects spodoptera littoralis and leptinotarsa decemlineata [42] . results of the study showed that the c13 and c15 hydroxy substituents are essential features of the active molecule, while the c11 benzoate group enhanced the biological effect on both insect species, where all of our alkaloids lacked those two substituents. in a taxonomic study done in 2002, lycoctonine-type alkaloids isolated from three delphinium species were classified into three groups according to the degree of their toxicity: n-(methylsuccinyl)-anthranoyllycoctonine (mal)-type with high toxicity, lycoctonine-type with moderate toxicity, and 7,8-methylene-dioxylycoctonine (mdl)-type with low toxicity [43] . in that paper, it was reported that the moiety attached to c14 is quite important for the toxicity of these alkaloids, which is also in accordance with our present data. furthermore, other functionalities on these molecules are also notable in terms of toxicity. it was noticed that the tertiary nitrogen, anthranilic acid substitution, and c1 moiety affect the toxicity degree within those alkaloids. for instance, when the methylsuccinyl group is removed from mal (which then converts to lycoctonine), lycoctonine becomes 93 times less toxic. briefly, our report was the first on antiviral, antibacterial, and antifungal activities of lycoctonine, 18-o-methyllycoctonine, delcosine, 14-acetyldelcosine, and 14-acetylbrowniine. furthermore, our data also suggest that all of the diterpene alkaloids are worthy of being evaluated for their antimicrobial and antiviral activities for future-promising results. in our recent work, we focused on investigation of antiviral activity of 33 isoquinoline alkaloids and seven derivatives of them, which are classified as protopine-type [protopine (14) and β-allocryptopine [44] , whose isolation procedures were described elsewhere [45] [46] [47] [48] [49] [50] (figs. 4 and 5) . moreover, the alkaloids were also tested against e. coli, p. aeruginosa, p. mirabilis, k. pneumoniae, a. baumannii, s. aureus, and b. subtilis, as well as the fungus c. albicans by the microdilution method, for their antibacterial and antifungal activities. according to our findings, all types of the alkaloids appeared to be more active to gram-negative bacteria than to gram-positive ones. most of the alkaloids, including protopine, β-allocryptopine, chelidimerine, fumarophycine, (±)-sibiricine, sibiricine acetate, (±)-dihydrosibiricine, parfumine acetate, α-hydrastine, (+)-bulbocapnine, berberine, (-)-canadine, (-)-ophiocarpine, ophiocarpine-n-oxide, corydalmine, oxosarcocapnidine, and corydaldine, showed significant inhibition on k. pneumoniae and a. baumannii, in particular, better than the rest of the gram-negatives, at 8 µg/ml concentration as compared to amp (2 µg/ml). all of the alkaloids, regardless of their structural differences, inhibited e. coli and p. mirabilis with mic of 32 µg/ml, while they inhibited s. aureus at 64 µg/ml. interestingly, the alkaloids that were found to inhibit k. pneumoniae and a. baumannii at 8 µg/ml also had remarkable inhibition on c. albicans (4 µg/ml), while a notable occurrence of antifungal activity was observed with the rest at 8 µg/ml concentration. the tested isoquinolines were observed to display a selective inhibition against pi-3 as seen in table 4 , except for (+)-isoboldine, (-)-stylopine, and (±)-corydalidzine, that were totally ineffective against both viruses. protopine, β-allocryptopine, chelidimerine, fumarophycine, α-hydrastine, (+)-bulbocapnine, (+)-isoboldine, (-)-sinactine, palmatine, dehydrocoryda-316 i. orhan et al. line, dehydrocavidine, (+)-cularicine, oxocularine, and oxosarcocapnine were completely inactive against hsv, whereas maximum cpe concentrations of the rest were the same as acyclovir (16 µg/ml). however, the alkaloids were revealed to be less cytotoxic than acyclovir on mdbk cells, (-)-canadine being the least cytotoxic alkaloid (128 µg/ml). the most active alkaloid with anti-pi-3 effect was shown to be protopine (1-32 µg/ml), followed by fumarophycine (2-32 µg/ml), chelidimerine, (+)-bulbocapnine, and (-)ophiocarpine (4-32 µg/ml), as well as β-allocriptopine and oxosarcocapnia number of antimicrobial, antiviral, antitumoral, antimalarial, and cytotoxicity studies have been so far reported on various derivatives of natural or synthetic isoquinoline alkaloids [51] [52] [53] [54] [55] [56] [57] . in one study, antimicrobial, cytotoxic, and anti-hiv activities of 26 simple isoquinolines and 21 benzylisoquinolines were investigated. the results showed that a quaternary nitrogen atom of isoquinoline or dyhydroisoquinoline type may enhance the potency of antimicrobial activity and cytotoxicity, whereas anti-hiv activity was higher with tetrahydroisoquinolines [58] . in the study of cui et al., simple isoquinolines, 15 of which were of 1-benzylisoquinoline-type and 19 of which were of protoberberine-derivatives, were screened against epstein-barr virus early antigen (ebv-ea) activation induced by 12-o-tetradecanoylphorbol-13-acetate (tpa), which is considered to be an indicator of antitumorpromoting activity. the study was carried out using raji cells and all 1benzylisoquinolines and 11 of the protoberberines exerted higher inhibitory activity than β-carotene [59] . regarding the structure-activity relationship, it was concluded that the inhibitory activity of 1-benzylisoquinolines increased as the number of hydroxyl groups on the aromatic ring increased and, additionally, the size of substituents at the c8 and c13, as well as type and position of the oxygenated substituents on a and d rings, influenced the virus inhibition. moreover, derivatives of the isoquinoline skeleton attached with carboxamide moiety were declared to be the potent and selective inhibitors of human cytolamegavirus [60] . in another study, the structure-activity relationships of berberine and its derivatives were examined for their antibacterial activity. among the 13-alkyl-substituted and the 13-unsubstituted protoberberinium salts, an increase in antibacterial activity was observed with the 13-ethyl-9-ethoxyl, the 13-ethyl, and the 13-methyl derivatives against s. aureus by eight-, four-, and twofold, respectively, over berberine, which suggested that steric effects played an noteworthy role in the antibacterial activity [61] . additionally, replacement of methoxyl groups at the c2 and the c3 of ring a by a methylenedioxy group caused a boost in activity. in this report, it was stated that the quaternary nitrogen atom (such as in protoberberinium salts) an alkylsubstituent at c13, and a methylenedioxy function at c2 and c3 are required for enhanced antibacterial activity. in a study by nakamoto et al., berberine was revealed to have a strong antifungal effect against c. albicans, c. tropicalis, and c. glabrata, respectively, which is in accordance with our data on berberine [62] . in a recent publication, a high occurrence of antibacterial activity in berberine was shown towards e. coli, k. pneumoniae, p. aeruginosa, p. fluorescens, s. aureus, salmonella typhi, enterococcus sp., and serratia marcescens, showing a better activity than streptomycin at 50 µg/ml by paper disc diffusion method. consequently, berberine was concluded to be responsible for the high antibacterial activity of coscinium fenestratum [63] . however, we found that berberine was only active against k. pneumoniae and a. baumannii by microdilution method, which might result from the application of two different methods. in another former study, berberine obtained from berberis heterophylla was tested against the atcc strains of s. aureus, enterecoccus faecalis, p. aeruginosa, e. coli, and c. albicans by agar diffusion method at 50, 100, and 200 µg/ml concentrations. the alkaloid was highly active against s. aureus at 100 and 200 µg/ml, whereas it did not possess any inhibitory effect against e. faecalis, p. aeruginosa, and e. coli [64] . this data was consistent with ours for berberine in the case of e. coli and p. aeruginosa. it was not active to s. aureus, which might again be the result of the use of two dissimilar methods. in the same work, antifungal activity screening was performed with berberine using the clinical strains of several candida sp. such as c. albicans, c. glabrata, c. haemulonii, c. lusitaniae, c. krusei, and c. parapsilosis. being the most active to c. krusei, followed by the rest in decreasing degrees of effectiveness, berberine was expressed as a novel antifungal agent. in one report, protopine and α-allocryptopine isolated from glaucium oxylobum were tested for their antifungal activity against microsporium canis, m. gypseum, tricophyton mentagrophytes, epidermophyton floccosum, c. albicans, aspergillus niger, and penicillium sp. [65] . among these fungi, protopine exerted low activity against m. canis and t. mentagrophytes, while α-allocryptopine had low activity towards m. gypseum and good inhibition of e. floccosum. in contrast, protopine was found to be inactive against c. albicans, whereas this alkaloid had a high inhibition against the same fungus in our study (4 µg/ml). α-allocryptopine was also inactive against c. albicans, whose β-counterpart exhibited a very good antifungal effect against c. albicans. this may reasonably be due to the αand β-conformation of the compound. in a previous study, the molluscicidal activity of argemone mexicana seeds were tested against the snail lymnaea acumi-nata, which led to isolation of protopine and sanguinarine as the active components [66] . from the structure-activity point of view, a few features about the isoquinoline alkaloids investigated herein can be pointed out. the quaternary nitrogen atom found on some of the isoquinolines such as dehydrocorydaline, dehydrocavidine, berberine, sanguinarine, and palmatine may have an effect on the decrease of antiviral activity. on the other hand, the synergistic interaction among the isoquinoline alkaloids isolated from f. vaillantii may be stated to contribute to the higher antiviral activity of this extract. protopinetype alkaloids seem to display a higher antiviral effect than the rest. from ancient to modern history, traditional plant-based medicines have played an important role in health care. many countries in africa, asia, and latin america still rely on traditionally used herbal medicines for primary health care needs. on the other hand, the complex nature of plant extracts and the high probability of competing or synergistic bioactivities within the same extract mean that these results represent the starting point for an activity-guided search for active plant metabolites. it is also evident that a structure-activity relationship exists between the various chemical structures and their antimicrobial activity in most cases. however, antiviral agents, unlike antibacterial drugs which may cover a wide range of pathogens, tend to be narrow in spectrum, and, unfortunately, have a limited efficacy. historically, the discovery of antiviral drugs has been largely fortuitous. spurred on by success with antibiotics, drug companies launched huge blind-screening programs with relatively little success. besides, lead compounds were modified by scientists in an attempt to improve bioactivity. however, there is still a great need to develop more effective antiviral and antimicrobial drug molecules. as a conclusion, these findings provide additional evidence for the supposition that the assays mentioned above play the part of useful primary screening in the survey of bioactive natural products. for the reasons outlined above, it is very important to focus on plants to discern novel antiviral/antimicrobial compounds. therefore, we truly hope that our studies, as well as similar reports by different researchers, may help find new antimicrobials/antivirals from herbal sources. the lancet (inf. diseases) key: cord-012623-bc9fj29h authors: pekmezaris, renee; kozikowski, andrzej; pascarelli, briana; handrakis, john p.; chory, ashley; griffin, doug; bloom, ona title: participant-reported priorities and preferences for developing a home-based physical activity telemonitoring program for persons with tetraplegia: a qualitative analysis date: 2019-05-16 journal: spinal cord ser cases doi: 10.1038/s41394-019-0188-6 sha: doc_id: 12623 cord_uid: bc9fj29h study design: focus group. objectives: the purpose of this qualitative study was to explore perceptions and priorities of persons with spinal cord injury (sci) for physical activity and to incorporate their feedback to inform future development of a physical activity program delivered via a telemonitoring platform. setting: new york. methods: qualitative data were collected from a purposive sample of adults with tetraplegia (n = 7). two investigators led an audio-recorded focus group using a moderator’s guide. data were analyzed using a six-phase thematic analysis approach. results: the discussion focused on two major areas, which resulted in multiple derived themes and subthemes. the first theme centered on the daily life of persons with tetraplegia, including changes after sci, gain of function prioritization, and identification of psychosocial support systems that facilitate community reintegration after injury. the second theme centered on participant perceptions and recommendations for a physical activity program delivered via a telemonitoring platform. desired design features included variations in schedule, diverse activities, or exercises included in each class, and optional two-way video to enable social interactions with classmates. conclusions: participants favorably viewed the concept of a physical activity program delivered via a telemonitoring platform and contributed program design ideas. although this was a small sample size, challenges to obtaining physical activity expressed by participants were consistent with those identified previously in larger studies of persons with tetraplegia. therefore, we expect these concepts and their recommendations to be relevant to the greater sci community. approximately 350,000 persons in the us are living with traumatic spinal cord injury (sci) [1, 2] . due to reduced mobility, persons with sci are at increased risk for developing obesity, muscle atrophy, osteoporosis, accelerated atherogenesis, type ii diabetes mellitus, and other medical consequences that increase the risk of stroke and coronary heart disease [1] [2] [3] . this reduced mobility often has deleterious psychosocial effects that impact quality of life, including increased social isolation, reduced social participation, reduced exercise self-efficacy, and depression [4, 5] . thus, there is a critical need for therapeutic strategies that reduce the risk of multiple medical and psychosocial consequences of sci. physical activity is a recommended therapeutic strategy to reduce risks of common medical consequences across diverse clinical populations [6, 7] . physical activity reduces risks of coronary heart disease and diabetes, increases immunity and blood circulation, and decreases inflammation, fat, anxiety, pain, and improves mood and sleep [8] [9] [10] [11] . the american college of sports medicine recommends that able-bodied adults perform 150 min of moderate-intensity aerobic exercise and participate in two or more days of muscle-strengthening exercise weekly [12] . the latest physical activity guidelines for adults with sci recommend, "at least 20 min of moderate to vigorousintensity aerobic exercise two times per week and three sets of strength exercise for each functioning muscle group, at moderate to vigorous intensity, two times per week" [13, 14] . for cardiometabolic health benefits, it is recommended that adults with sci engage in at least 30 min of moderate to vigorous-intensity aerobic exercise three times per week [13, 15] . persons with sci and other disabilities are less likely to engage in regular physical activity, due to many modifiable barriers. these include: lack of knowledge about existing programs/safe exercises, insufficient programming, lack of transportation, cost, and scheduling issues [16] . there are also other barriers, such as feeling too hot or cold outdoors or distance from an adaptive sports facility [17] . in the general population, telemonitoring approaches to delivering physical activity are part of a highly successful commercial fitness industry. consumers are offered the ability to choose a program to engage in at home, with recorded or live classes, that can be delivered to a tv, tablet, phone, or computer via a commercial internet provider. compared to a gym membership, telemonitoring is convenient, scalable, and relatively low cost. regardless of the modality, telemonitoring physical activity programs often require minimal exercise equipment and are delivered at home on a personalized schedule. in addition to the physical health benefits, such as increased muscle strength and improved cardiovascular fitness, many physical activity instructors also engage actively in motivational strategies, to promote adherence and increase exercise self-efficacy [18] . increasingly, telemonitoring enables a participant to experience self-efficacy in the following ways: (1) mastery of experiences, the strongest predictor of self-efficacy, relate to actual performance when successfully meeting a challenging task. participants performing daily health behaviors and seeing progress, experience mastery. (2) vicarious modeling (seeing others facing similar challenges and reaching their goals) will be achieved by viewing other participants of similar abilities attaining activity goals. (3) social persuasion (verbal encouragement) is provided by the instructor. (4) physiological factors, such as anxiety and distress, can be experienced by participants when they fail to meet activity goals; the instructor can interpret this as situational and not associated with overall success [19, 20] . home-based physical activity delivered via telemonitoring may be a particularly useful option for persons with sci as a way to modify common environmental barriers to achieve the benefits of regular physical activity [21] . to address these and other barriers, telehealth approaches are being increasingly studied in the context of sci [21] . sweet and colleagues are starting an rct of an 8-week tele-rehab program for persons with paraplegia to measure changes in psychosocial variables related to exercise participation and quality of life [22] . another study measured the effects of a home-based exercise program in persons with chronic sci, including outcome measures of metabolism, body composition, physical activity, energy intake, measures of health and wellbeing, resting metabolic rate, heart rate, and blood pressure, aerobic capacity, immune function, and adipose gene expression [23] . encouraging results using telemonitoring have been obtained across physical health measures (i.e., wound care), as well as psychological health [21] . there is a need to establish novel methods to facilitate regular physical activity for persons with sci [24] . here, we report the results of a qualitative study of priorities and preferences for developing a home-based physical activity telemonitoring program for persons with tetraplegia. we consider this to be a first step towards optimizing feasibility and acceptability in a physical activity program for persons with sci [13] . this is a qualitative study of adults with chronic (at least 1 year from injury) tetraplegia who were recruited from the ny metropolitan area. the rationale for including only persons with tetraplegia was because, in general, this group has fewer opportunities for achieving physical activity in their daily life, lower reference values of cardiovascular fitness (relative vo2 peak), higher risk factors for cardiovascular disease, and lower life expectancy than persons with paraplegia. a short demonstration video developed by the study team was presented to participants to show the concept of a telemonitoring physical activity program led by a physical therapist for persons with tetraplegia. moderators explained that they envisioned that participants would join the class via a tablet with a split screen that showed themselves, the instructor, and classmates conducting exercises. moderators described that an instructor would monitor vital sign data (heart rate and blood oxygenation) of participants in real time via a pulse oximeter. before engaging in exercise, participants would be trained on proper equipment use. for safety, participants would be asked by the instructor every 5 min during the intervention, to describe any symptoms of discomfort, including pain (musculoskeletal or other), fatigue, shortness of breath, or dizziness. frequency, duration, and type of proposed activities are based on the most recent guidelines on physical activity for persons with sci [24] . the intervention presented was proposed to be delivered three times/week for 45 min, with ≥30 min of activity. the circuit training program proposed was based on evidence of strength and cardiorespiratory benefit in persons with sci [25] . stretching, cardiovascular, and strengthening exercises would be tailored to participants' functional abilities. theraband, with open handgrips (loops), would be used to provide resistance for strength training [26] . moderators explained that the program would consist of three repetitions of: (a) warm-up: a series of active (nonresisted) movements: shoulder lateral raises, flies, shoulder rolls, wide biceps curls, shoulder shrugs, triceps extensions to rear; (b) circuit exercise program: resistance followed by aerobic (arm spinning) exercises with rest periods as needed (~15 s). resisted movements would include: set 1: seated rows, horizontal shoulder abduction, arm spinning/circles (aerobic exercise), set 2: shoulder internal rotation, shoulder external rotation, aerobic exercise, set 3: straight arm pulldowns, chest press, aerobic exercise [26] . a 3-h focus group was conducted in january 2018, led by two moderators previously unknown to participants. moderators used a moderator guide with open-ended questions and probes, related to a range of relevant topics including experiences with and priorities for benefits of physical activity before and after their injuries, technology use, and perceptions of important features that should be incorporated into a telemonitored physical activity program. the discussion was digitally recorded (using two recorders in case of technical failure), stored on an internal password protected server to ensure security, and transcribed professionally. transcripts were checked against the original recordings for accuracy. to optimize credibility, transferability, and dependability of results, we utilized analyst triangulation, peer debriefing, and conducted an audit trail of decisions made during the analysis and rationale. the transcript was analyzed by two researchers (a k and b p), to achieve triangulation to gain a more complex understanding of the data. a six-phase thematic analysis approach was utilized [27, 28] . in the first phase, transcripts were reviewed independently multiple times to become familiar with the data. researchers documented initial theoretical and reflective thoughts, and potential codes and themes. in the second phase, researchers focused on data patterns and generated a comprehensive set of codes through inductive and deductive coding. two researchers documented their reasoning for coding blocks of text from the transcript of the focus group to explain how the data were perceived and examined. the third phase consisted of searching for themes after coding and codes were collated. in the fourth phase, themes were reviewed and refined. criteria for retaining themes were that they needed to be specific enough to be concrete, while broad enough to capture ideas. themes with sparse data were eliminated and those with large amounts of data were further divided into separate themes. in the fifth phase, team members met and discussed the finalization of theme names. in the sixth phase, the report was generated. participants were persons with tetraplegia (n = 7: 5 males and 2 females) who were wheelchair users for community mobility. the discussion explored challenges of living with tetraplegia, gain of function prioritization, social networks, and design recommendations for a telemonitored physical activity program. participants were asked to rank their gain of function prioritization on a seven-point scale, with one being most, and seven being least important, in the following areas: arm/ hand function, upper body/trunk strength and balance, bladder/bowel function, lived experiences of sexual function, elimination of chronic pain, sensation and mobility ("mobility could be anything that gets your body around in space") [29] . most participants ranked either arm/hand function, sensation, or improvement of mobility as the most important. the next gain of function priorities ranked was upper body/trunk strength and balance, elimination of chronic pain, and sexual function. two major discussion themes emerged from a six-phase thematic analysis approach to the transcript. theme one: daily challenges pain several participants described challenges of performing activities of daily living (adls) while experiencing constant pain. the locations of pain symptoms varied by individual, including the back, neck, shoulders, and feet. multiple participants reported that pain symptoms were worse in the morning and did not resolve completely throughout the day. "right now, i feel like someone's kicking me in the back but that's normal for me, so it's just one of those things you kind of deal with…" "…i have chronic back pain that just will not go away. it's probablyif i say on a scale of one to ten, it's probably around a good eight most of the day…" "i'm in pain every day when i get home. i'm in bed by 7:00 because i can't even function." participants also discussed how pain impacted feelings of fatigue and strategies to cope with interruptions in sleep. "and you talk about getting exhausted during the day. i want to sleep every day by 12:00. but i'm at work, so i can go in my office for a little while just to try to rest for a minute." multiple participants reported being athletic and active prior to their sci, had careers in physically enduring professions or participation in active sports including swimming, motocross, running, cycling, and skiing. "yeah, motor cross. yeah. so i used to ride-a lot of cycling, a lot of swimming. i had a home gym that i worked out in all the time. running-i was a terrible runner because my knees weren't that great. so i would run a little bit, but not that much. mostly cycling. i loved cycling. anything with wheels, i was there." "i was very free spirited, i'd say. we'll put it that way. but yeah, i sort of was very spontaneous and enjoyed flying by the seat of my pants and all that. it's like losing a little piece of you." as expected, the intensity and type of physical activity changed for most participants after injury. most focus group participants were not engaged in regular physical activity, outside of the exercises prescribed during physical therapy. for participants who were active, post-injury activities include using a stationary bike, thera-bands for resistance training, and free weights. "when i first came home, i was doing them every day. and then little by little, you're slacking off. but like i said, every day, once i get into bed, that's when i do the most thera-bands or weights or anything because i'll put a wrist [adaptor] on my arm. i'll go on my side and i'll do the left arm. then i get turned the other way, i'll do the right arm." "...everything from thera-bands like you were talking, to cuff weights. i use cuff weights as well that-most people use them on their ankles when they're running or exercising, but they also work great for quads around your arm. it's like a velcro weight. the rickshaw [wheelchair rehab exercise machine]…. it's a great machine for people in wheelchairs. and they have another machine there which is called the upper tone…it's kind of a home gym-type looking machine that's specifically designed for people in wheelchairs and people with limited hand function." variation in physical therapy and interactions with physical therapy personnel were discussed and perceived as impacting the post-injury rehabilitation process. "i've been to great therapists and i've been to not-sogreat therapists, and what they did clinically was not that different from each other. the difference was the therapists' behavior, the interaction." "i mean, it felt like it's a total package there. you get a lot of focused attention. youand theystart on the dime and they give you every second of that hour." participants discussed the critical role of social networks (family and friends) in community reintegration after injury. in addition, participants were motivated and inspired by interacting with peers with sci who demonstrated resilience. "…when you see people getting better, it helps. it makes you believe you can do the same thing too." the importance of self-efficacy to obtaining functional gains was also discussed, including the importance of maintaining both physical and emotional health. the feelings of well-being obtained from exercise were reported to reinforce the desire to continue exercising. "when i'm in a good mood, i feel i can conquer the world. but when i'm in a lousy moodlike today is not a great mood for meis i don't feel good about anything, and i don't want to do anything because i'm miserable. but then tomorrow i'll feel great and say i can pretty much take on the world and do anything i want and just let me do what i got to do." "yeah, inspirational. yeah, it would raise inspiration, want me to build more muscle on my end to want to feel better and know that i'm healthier and to keep going for whatever reason, whether it's for walking or not." "and i can tell you personally that i should probably be further along physically than i am… i think i plateaued and then went the other direction because of my own inability to push those things out of my mind…like if your head's not there, like in anything in life, but especially with sci rehab, it's hard enough knowing that this happened." participants discussed the importance of recognizing that goals and priorities may vary by individual and that each person will begin the program looking for a different outcome. for some, success may be defined as an improvement in mobility, whereas for others success may be defined as increased social interactions, motivation, or health maintenance. "i think everybody's priorities and everybody's goals are different." "so i mean, so i don't want to lose those [functions] any worse than they've been getting over the years because it's like almost limited to what i can kind of do…" "well, i guess it depends on somebody's lifestyle and age has a lot to do with it. so i would say some people are just looking to maintain themselves and stay healthy to be able to continue to do the activities that they currently do." "yeah, and just feeling better as well in daily activities." interaction with other classmates a strong recommendation was made to foster potential interactions among classmates in order to motivate and inspire one another. an additional recommendation was to include a feature to extend class times to allow for social interactions among classmates before or after exercise. some participants suggested that two-way viewing among classmates should be optional, so as to not discourage those who might feel uncomfortable. "i think it would be key to interact with not only the therapist, but with other patients. so i see jack on the one screen and he's struggling, i'm like come on. do one more. do one more. and we're all telling himme, alex-jack, come on. do one more. and he pulls through, so it gives that mental back." "so you said a 45-minute designed program, but maybe its 60 min and we all log on 15 min before. we could all-oh, maria*, how's that going, or chris*, how's that? so the social muscle to it instead of just working on arms and then logging off, like good old talk." "but to have the ability to [see others] should certainly be an option… but they should at least have the option to turn it off if they want i think, right?" participants suggested that it would be helpful for someone to orient a class member, assist with equipment needs and demonstrate specific exercises included in the program prior to session initiation. participants suggested that including a variety of exercises within each class would be desirable, in order to meet personal preferences and to address varying physical abilities. multiple participants suggested that three times per week would be the preferred frequency of classes, held at a variety of days and times to accommodate different schedules (e.g., weekday, weekend, and evening sessions). the goal of this focus group was to discuss experiences with physical activity and gather input from persons with tetraplegia to inform future design of a physical activity program delivered via telemonitoring that would be feasible, acceptable, and consistent with exercise guidelines for those with sci. a minor aspect of the discussion revealed that, in general, priorities for improvement included: arm/hand function, sensation, and improvement of mobility as being most important. in addition, upper body/trunk strength and balance, elimination of chronic pain, and improving lived experiences of sexual function were also ranked as important. data demonstrate that different modalities of exercise and physical activity have indeed been shown to improve aspects of physical capacity, health, and abilities to perform activities of daily living (e.g., functional wheelchair maneuvers and transfers) in persons with sci [30] . participants perceived a home-based physical activity program as needed and important. intensity and type of physical activity performed before and after injury were discussed. participants identified family support, psychological state, and having a peer network (e.g., others with sci) as important factors for their overall recovery. participants regarded their input and feedback as critical for ensuring usability and feasibility, including the ability to make choices regarding whether a participant can be seen by classmates, types of exercises in a class, and timing of class delivery to suit multiple schedules. participants generally expressed enthusiasm for interacting with classmates, a desire for help from a caregiver or professional in initial set up, and comfort with a frequency of three times/week for classes and a duration of 45-60 min per class. participants perceived multiple potential benefits of a physical activity for persons with sci delivered via telemonitoring. participants had several practical suggestions to optimize design and delivery of such a program. clearly, a pilot study in this population testing this kind of intervention is needed. it is important that future studies incorporate feedback from participants on the design and implementation of a physical activity program. data generated during the focus group are not publicly available in order to protect privacy of participants. deidentified data can be made available upon request to the corresponding author. publisher's note: springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. open access this article is licensed under a creative commons attribution 4.0 international license, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the creative commons license, and indicate if changes were made. the images or other third party material in this article are included in the article's creative commons license, unless indicated otherwise in a credit line to the material. if material is not included in the article's creative commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. to view a copy of this license, visit http://creativecommons. org/licenses/by/4.0/. annual statistical report for the spinal cord injury model systems public version traumatic spinal injury: global epidemiology and worldwide volume facts and figures at a glance facilitators and barriers to social and community participation following spinal cord injury social and community participation following spinal cord injury: a critical review position statement. part two: maintaining immune health position statement. part one: immune function and exercise reduction in trunk fat predicts cardiovascular exercise training-related reductions in c-reactive protein exercise and respiratory tract viral infections cardiovascular exercise training extends influenza vaccine seroprotection in sedentary older adults: the immune function intervention trial exercise, inflammation, and innate immunity american college of sports medicine position stand. quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise evidence-based scientific exercise guidelines for adults with spinal cord injury: an update and a new guideline development of scientific exercise guidelines for adults with spinal cord injury the development of evidence-informed physical activity guidelines for adults with spinal cord injury more than just a game: the public health impact of sport and physical activity for people with disabilities (the 2017 delisa lecture) functional and environmental factors are associated with sustained participation in adaptive sports self-efficacy: the exercise of control self-efficacy: the exercise of control self-efficacy mechanism in human agency correlates and determinants of physical activity in persons with spinal cord injury: a review using the international classification of functioning, disability and health as reference framework participation in physical activity in persons with spinal cord injury: a comprehensive perspective and insights into gender differences participation in sport in persons with spinal cord injury in switzerland telehealth for people with spinal cord injury: a narrative review circuit training provides cardiorespiratory and strength benefits in persons with paraplegia a comparison of 2 circuit exercise training techniques for eliciting matched metabolic responses in persons with paraplegia using thematic analysis in psychology causes of death during the first 12 years after spinal cord injury targeting recovery: priorities of the spinal cordinjured population exercise and health-related risks of physical deconditioning after spinal cord injury acknowledgements the authors appreciate the time, effort, and opinions of the focus group participants.funding a grant from the new york state spinal cord injury research board (to ob) and institutional funds supported this work. these funds were used to support sci-related research at our institution and did not influence the specific study in any way.authors' contributions rp, ak, jh, dg, and ob designed the study. rp and ak led development of the moderator guide, to which all authors made contributions. jh and dg developed the proposed physical activity program. rp, ak, jh, dg, and ob created the demo video of the proposed physical activity program. all the authors (rp, ak, jh, dg, ac, bp, and ob) were present for the focus group. rp and ak moderated the focus group. ak and bp analyzed the transcript and wrote the report. all the authors (rp, ak, jh, dg, ac, bp, and ob) contributed to interpreting the data and writing the manuscript. conflict of interest the authors declare that they have no conflict of interest.ethics study activities were deemed not human subject research by the local institutional irb research and therefore did not require irb review. key: cord-272943-q09i8fqu authors: dalhoff, a. title: antiviral, antifungal, and antiparasitic activities of fluoroquinolones optimized for treatment of bacterial infections: a puzzling paradox or a logical consequence of their mode of action? date: 2014-12-17 journal: eur j clin microbiol infect dis doi: 10.1007/s10096-014-2296-3 sha: doc_id: 272943 cord_uid: q09i8fqu this review summarizes evidence that commercially available fluoroquinolones used for the treatment of bacterial infections are active against other non-bacterial infectious agents as well. any of these fluoroquinolones exerts, in parallel to its antibacterial action, antiviral, antifungal, and antiparasitic actions at clinically achievable concentrations. this broad range of anti-infective activities is due to one common mode of action, i.e., the inhibition of type ii topoisomerases or inhibition of viral helicases, thus maintaining the selective toxicity of fluoroquinolones inhibiting microbial topoisomerases at low concentrations but mammalian topoisomerases at much higher concentrations. evidence suggests that standard doses of the fluoroquinolones studied are clinically effective against viral and parasitic infections, whereas higher doses administered topically were active against candida spp. causing ophthalmological infections. well-designed clinical studies should be performed to substantiate these findings. the history of quinolones began in 1962 with the isolation of a byproduct of chloroquine synthesis by george yohe lesher and colleagues [1] at the sterling-winthrop research institute in rensselaer, new york; this compound was found to be antibacterially active and was subsequently modified to yield nalidixic acid. nalidixic acid and chloroquine share structural features being essential for their antibacterial and antiparasitic activity, respectively. apart from its well-known antimalarial effects [2] [3] [4] , chloroquine exerts direct antiviral [5] [6] [7] [8] [9] [10] [11] [12] [13] , antifungal [13] [14] [15] [16] , and antibacterial effects [13, [17] [18] [19] [20] . furthermore, chloroquine exhibits immunomodulatory activity [21] [22] [23] [24] [25] and was found to reverse p-glycoprotein (p-gp)-mediated multidrug resistance, thereby increasing the cytotoxicity of some antineoplastic agents [26] [27] [28] [29] [30] . the antimalarial effects of chloroquine are due to its accumulation in acidic food vacuoles of intraerythrocytic trophozoites, thereby preventing hemoglobin degradation and inhibition of a haem polymerase enzyme [3, 4] . the antiviral, antifungal, and antibacterial activities of chloroquine are ph-dependent [10, 14, 16, 18 ]. this phenomenon is due to the fact that chloroquine is a weak base and, therefore, does not enter the cell if the extracellular fluid or the incubation medium is acidic. once chloroquine has entered cells, it intercalates into dna and prevents the introduction of topoisomerase ii-mediated dna breaks. the intercalation of chloroquine into dna protects cells against epipodophyllotoxins such as etoposide, acting as topoisomerase ii poison by hindering the dna cleavage reaction of this target enzyme [31, 32] . the use of chloroquine in the treatment of some autoimmune diseases and its antiinflammatory properties may be due to the inhibition of mhc class ii antigen presentation; the inhibition of t-cell response may be due to a direct interaction of chloroquine with the cell membrane [22] . furthermore, chloroquine was found to destabilize indirectly lysosomal and plasma membranes as a result of accumulation within the lysosome, followed by an increase in lysosomal volume; it also sequesters important cell membrane constituents in lysosomes [29] . chloroquine was found to adsorb to the plasma membrane of yeasts, inhibit competitively the binding of immunoglobulin g to the cell surface, altered phospholipid turnover, and influenced directly but non-specifically the membrane integrity and permeability of renal brush border vesicles, mast cell membranes, and fibroblasts [16, [33] [34] [35] . furthermore, chloroquine blocks the inward rectifier potassium channel kir2.1; it is bound at the center of the cytoplasmic domain of the channel [36, 37] . these data demonstrate that the congener of fluoroquinolones, i.e., chloroquine, exhibits, apart from its antimalarial activity, pleiotropic actions and interacts with multiple targets. as chloroquine and nalidixic acid share structural features being essential for their activity, it was not surprising that it has been recognized in the late 1980s that nalidixic acid and oxolinic acid derivatives exert trypanocidal and antitumor activities [38] ; in the early 1990s, it was described that fluoroquinolones used for the treatment of bacterial infections exert not only an antibacterial but also an antiprotozoal activity [39] and may find applications as antiparasitic, antifungal, or antiviral agents [40] . furthermore, and in analogy to chloroquine, the activity of antibacterially active fluoroquinolones is ph-dependent [41] , and they bind directly to bacterial dna, i.e., two molecules intercalate at the highly bent dna gate in the dna cleavage domain [42] [43] [44] [45] [46] . despite these phenotypic and molecular homologies between chloroquine and fluoroquinolones, the pharmaceuticals industry invested financial and human resources into focused research programs on the application of developmental fluoroquinolones as antibacterials only and into pre-and postmarketing studies supporting the use of fluoroquinolones in the oncegranted indications. studies on the function of an antibacterial agent exerting pleiotropic anti-infective actions have never been performed systematically. surprisingly, the use of fluoroquinolones in indications other than bacterial infections has never been exploited, although not only nalidixic acid and its congener chloroquine exerts pleiotropic actions but, e.g., β-lactams and aminoglycosides are characterized by a broad range of biological activities too [47, 48] , so that a multitude of antimicrobial effects would not have been unusual. this review summarizes the pleiotropic phenotypes of nonantibacterial actions of fluoroquinolones and addresses the question if the diversity of effects are due to one common mode of action of antibacterially active fluoroquinolones, i.e., inhibition of essential bacterial type ii topoisomerases, or if other mechanisms may mediate non-antibacterial activities. although the complexity and diversity of prokaryotic and eukaryotic topoisomerases is remarkable and little or no sequence homology of amino acids exists, type i and type ii topoisomerases share certain structural elements mediating identical functions like dna relaxation or dna transport in bacteria, dna viruses, yeasts, and parasites; the dna helicase coordinates the directionality of topoisomerase activity; rna helicases as present, e.g., in hepatitis c virus (hcv) directly interact with double-stranded dna or rna and assembles complexes with type ii topoisomerases [49] [50] [51] [52] [53] . as dna topoisomerases are ubiquitous enzymes controlling dna topology, it is conceivable that antibacterially active quinolones may not only inhibit the growth of bacteria at clinically relevant concentrations, but that of other prokaryotic and even eukaryotic organisms as well. ciprofloxacin, ofloxacin, levofloxacin, and gatifloxacin were found to be clinically effective in the treatment of the singlestranded rna hcv and the non-enveloped, encapsulated dna polyomavirus bk [54] [55] [56] [57] [58] [59] [60] . five and four patients with hcv-induced chronic hepatitis and compensated liver cirrhosis, respectively, were treated with 100 to 900 mg ofloxacin per day for one to eight weeks. in three patients with chronic hepatitis and one patient with compensated liver cirrhosis, hcv rna decreased at least by 1 log titer [54] . in another study, five patients with chronic hcv were treated with 500 mg ciprofloxacin twice daily (b.i.d.) for 30 days. serum hcv rna levels remained largely unchanged in these patients [55] . the latter study indicates that the anti-hcvefficacy of quinolones may be limited in patients with advanced liver cirrhosis. ciprofloxacin decreased bk peak viral load after hematopoietic stem cell transplantation [56] . a reduction of viremia was demonstrated two months after a 10-day course of gatifloxacin at 400 mg/d in 7 of 10 transplant recipients with active bk virus replication [57] . a retrospective analysis revealed that the use of either ciprofloxacin 250 mg b.i.d. or levofloxacin 250 mg once daily (q.d.) within the first month post transplantation and up to 3 months after transplantation was associated with significantly lower one-year rates of bk viremia [58] . a recent study in nine kidney transplant recipients with persistent bk infection revealed that, three months post ciprofloxacin treatment with 250 mg b.i.d for 30 days, the virus load was cleared completely in three patients and decreased by >50 % in another three patients [59] ; patients were not treated with anti-infectives other than fluoroquinolones. fluoroquinolones inhibit bk viral replication in vitro. ofloxacin and levofloxacin inhibited polyomavirus bk replication in primary human kidney cells in a dose-dependent manner, yielding a~90 % inhibition at 150 μg/ml. bk virus genome replication was reduced by 77 % at 48 h post infection of the kidney cells. at 72 h after inoculation of the kidney cells, the reduction in genome replication and protein expression was less pronounced. a dose-dependent cytostatic effect was noted. in infected cells, 150 mg/l ofloxacin led to a 26 % and 6 % inhibition of cellular dna replication and total metabolic activity, respectively, while 150 mg/l levofloxacin exhibited a slightly more marked cytostatic effect, particularly in uninfected cells [60] . ciprofloxacin, moxifloxacin, levofloxacin, ofloxacin, gatifloxacin, and norfloxacin inhibited bk virus replication to 50 % at concentrations ranging from 66.7 to 266.6 mg/l [61] . ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and trovafloxacin inhibited viral replication of simian virus 40 (sv40), another member of the polyomaviridae, in permissive monkey cells, as well as plaque formation, dna replication, and helicase activity. ciprofloxacin, levofloxacin, and ofloxacin inhibited "significantly" helicase activity at 0.5, 1.0, and 2.0 mm, whereas trovafloxacin inhibited helicase activity at 50 μm [62, 63] . recently, it was demonstrated that norfloxacin, ofloxacin, flumequine, enrofloxacin, cinoxacin, enoxacin, fleroxacin, lomefloxacin, balofloxacin, and difloxacin inhibited hcv replication, in particular, hepatoma huh-7 and huh-8 cell lines, and hcv ns3 helicase activity. the concentrations inhibiting hcv rna replication to 50 % ranged from 3.3 to 8.2 μm and those inhibiting helicase activity ranged from 4.1 to 9.9 μm [64] . the clinical studies reviewed above and one recent report of a successful treatment of a kidney retransplant patient with ciprofloxacin (250 mg b.i.d. for 10 days) who needed an overall increase of immunosuppression due to acute rejection [65] suggest that fluoroquinolone treatment of polyomavirus bk infections in transplant patients may be beneficial. therefore, a study protocol for a randomized controlled clinical trial evaluating the prophylactic efficacy of fluoroquinolones has been designed and is registered at clinicaltrials.gov under nct01353339; levofloxacin at a dose of 500 mg q.d. will be administered for 3 months and will be compared to placebo [66] . another clinical study on the use of ciprofloxacin (250 mg q.d. for 3 months as compared to placebo) for the prevention of bk infections is registered under nct01789203 [67] . furthermore, it was demonstrated that ofloxacin [68] and levofloxacin [69] inhibited viral topoisomerase activity of vaccinia virus but not of herpes simplex virus and influenza virus [68] . in agreement with this finding, it was reported that 200 mg/l each of ciprofloxacin, lomefloxacin, ofloxacin, pefloxacin, and rufloxacin inhibited to 50 % the cytopathic effect of herpes simplex virus type 2 at concentrations being equivalent to the cytotoxic effect of the quinolones on the vero cells [70] . fluoroquinolones inhibit not only enzymic activity of viral topoisomerases/helicases, but inhibit in vitro human immunodeficiency virus (hiv) reverse transcriptase as well; complete inhibition was observed at concentrations of ciprofloxacin and ofloxacin of 3 μm and norfloxacin of 1 μm, respectively [71] [72] [73] . inhibition of rhinovirus (rv) infection by quinolones is due to the inhibition of cell functions required for viral replication. levofloxacin pretreatment of not yet infected human tracheal epithelial cells reduced the mrna level of intercellular adhesion molecule 1 (icam-1), a receptor for rv, in the cells and the concentration of the soluble form of icam-1 in the supernatant, so that rv infection of the tracheal epithelial cells was significantly reduced. levofloxacin pretreatment also decreased the number of the acidic endosomes from which rv rna enters the cytoplasm. furthermore, levofloxacin pretreatment inhibited the activation of nuclear factor κb proteins. these data suggest that levofloxacin inhibits rv infections first by reducing icam-1 expression levels and the number of acidic endosomes, and second by modulating airway inflammation [74] . fluoroquinolones other than levofloxacin have not been studied in this context. moxifloxacin and gatifloxacin inhibited, at a concentration of 0.5 % used for topical application in ophthalmology, candida spp. to >95 % [75] . gatifloxacin and sparfloxacin showed activity in a qualitative paper disk diffusion test against trichophyton rubrum, fusarium solani, and candida albicans, but not against saccharomyces cerevisiae [76] . ciprofloxacin, moxifloxacin, levofloxacin, trovafloxacin, and sitafloxacin enhanced the activities of antifungal agents against candida albicans and aspergillus fumigatus [77] [78] [79] [80] [81] [82] [83] [84] . furthermore, ciprofloxacin showed synergism with azoles against histoplasma capsulatum and coccidioides posadasii [85] , as well as in combination with amphotericin b against exophiala spinifera [86] . several but still rare reports of clinical and microbiological cure of fungal keratitis by quinolones have been published; recently, five additional cases of fungal keratitis treated successfully with topical moxifloxacin monotherapy were published [79] . the causative organisms curvularia spp., candida parapsilosis, paecilomyces lilacinum, and aspergillus fumigatus were treated with moxifloxacin 0.5 %, one drop every half-hour to every hour. all these cases of fungal keratitis were cured with topical moxifloxacin and the pathogens were eliminated [87] . these data demonstrate that topical administration of quinolones, thus generating high target site concentrations, are clinically effective in the treatment of fungal ophthalmological infections. topoisomerase ii has been identified as the primary target for quinolones in yeast [88, 89] , so that the antifungal activities of the fluoroquinolones tested are likely to be mediated by this enzyme. the dna topoisomerase ii isolated from candida albicans was more susceptible to quinolones than the calf thymus dna topoisomerase ii, despite the fact that both enzymes are of eukaryotic origin [80] . yeast dna topoisomerase ii selected for resistance to quinolones are characterized by amino acid mutations which are homologous to mutations in gyra of escherichia coli [90] [91] [92] . these differences between yeast and mammalian type ii topoisomerases may explain why fluoroquinolones exhibit an antifungal activity by maintaining in parallel a selective toxicity against prokaryotic topoisomerases. although antibacterially active fluoroquinolones were derived from the antimalaria agent chloroquine, the clinical efficacy of norfloxacin against plasmodium falciparum was discovered by chance when the agent was used for the treatment of typhoid fever in indian patients. norfloxacin was administered to nine hospitalized malaria patients orally with 400 mg norfloxacin b.i.d. for three days; treatment led to disappearance of splenomegaly [93] . later, another 15 patients with uncomplicated malaria were treated with norfloxacin (ten with 400 mg b.i.d. and five with 800 mg b.i.d.) for three days [94] . this study confirmed that norfloxacin is clinically effective in the treatment of falciparum malaria, but the efficacy of the lower dose was suboptimal. later, it was demonstrated that norfloxacin is inferior to chloroquine for falciparum malaria. a prospective, randomized trial revealed that the mean parasite clearance time as well as the mean defervescence time were shorter in the chloroquine group [95] . fluoroquinolones like ciprofloxacin, amifloxacin, enoxacin, norfloxacin, ofloxacin, pefloxacin, grepafloxacin, trovafloxacin, and 16 additional commercially available quinolones exhibit marked in vitro activity and in vivo efficacy against plasmodium spp. [96] [97] [98] [99] [100] [101] [102] [103] [104] [105] . nalidixic acid and several fluoroquinolones like ciprofloxacin, norfloxacin, enoxacin, ofloxacin, fleroxacin, clinafloxacin, pefloxacin, and sparfloxacin exerted an antitrypanosomal in vitro and in vivo effect at micromolar concentrations [38, [106] [107] [108] [109] [110] [111] [112] [113] [114] [115] [116] . in addition, nalidixic acid, norfloxacin, ofloxacin, moxifloxacin, gatifloxacin, lomefloxacin, and some more fluoroquinolones inhibited growth of the microsporidia encephalitozoon intestinalis and vittaforma corneae to 50 % at concentrations ranging from 0.9 to 98.4 μm [112] . furthermore, ciprofloxacin caused a 50 % growth inhibition of babesia microti, b. bigemina, b. caballi, b. equi, and b. bovis at concentrations of 2.5 to 15.8 μm [113] . fluoroquinolones exerted antitoxoplasma activities as well. moxifloxacin, gatifloxacin, trovafloxacin, and grepafloxacin were the most active agents, inhibiting growth of t. gondii to 50 % at concentrations ranging from 0.4 to 5.1 mg/l, while ciprofloxacin was poorly active, with a 50 % inhibitory concentration value of 79.4 mg/l [116] . the parasites of the phylum apicomplexa, i.e., plasmodium spp., toxoplasma spp., babesia spp., and leishmania spp. are characterized by the absence of organelles like mitochondria, but they have acquired a plastid by endosymbiosis of a green alga. the apicoplast is a nonphotosynthetic plastid in which several essential biosynthetic pathways are sequestered, so that interactions with these biosynthetic functions cause deleterious effects. elimination of the plastid or total inhibition of its function results in a "delayed death", i.e., the parasites grow and evade normally within and from the first host cell, but their replication is halted immediately after the invasion of a new host cell. the apicoplast harbors a circular dna and bacterial type dna gyrase. ciprofloxacin induced cleavage of apicoplast dna in p. falciparum, without targeting nuclear dna [117] [118] [119] . exposure of toxoplasma gondii to ciprofloxacin resulted in a decrease of the apicoplast genome copy number during replication [120] . although it was discussed that differences in the role of apicoplasts in toxoplasma and plasmodium may exist [121] , the apicoplast dna gyrases isolated from both species were inhibited by almost identical concentrations; the apicoplast dna gyrase isolated from plasmodium falciparum is inhibited by ciprofloxacin concentrations ranging from 7 to 38 μm and trovafloxacin inhibits apicoplast dna gyrase activity isolated from toxoplasma gondii and plasmodium falciparum, respectively, at 30 μm [102, [117] [118] [119] [120] [121] . consequently, prokaryotic type ii dna topoisomerase of apicomplexan protozoa are effectively targeted by fluoroquinolones. it has been summarized previously that fluoroquinolones are active in preclinical infection models against quinoloneresistant bacteria as well as candida albicans infections [122, 123] . furthermore, levofloxacin was active against rv infections [74] . these phenomena were found to be directly correlated to the immunomodulatory activities of fluoroquinolones [122, 123] . mechanisms underlying the various immunomodulatory effects of fluoroquinolones include an effect on intracellular cyclic adenosine-3,5-monophosphate and phosphodiesterases, as well as an effect on transcription factors and also a triggering effect on the eukaryotic equivalent of bacterial sos response with its ensuing intracellular events [124] . fluoroquinolones are routinely prescribed for the treatment of coronavirus-associated severe acute respiratory syndrome (sars) or opportunistic bacterial infections in hiv-positive patients. upon elimination of the bacterial pathogen or exclusion of bacterial pathogens, antibiotic therapy can be withdrawn. however, patients may benefit from the immunomodulatory activities of fluoroquinolones, but their effect on the course of sars or acquired immune deficiency syndrome (aids) is undetermined. although it is well documented that nalidixic acid and fluoroquinolones modulate immune responses by the modulation of intracellular signaling cascades, it is unknown which mechanism(s) may trigger signal transduction. it has been d e m o n s t r a t e d t h at , i n a n a l og y t o c hl o r o q ui n e , fluoroquinolones bind to and insert into pro-and eukaryotic membranes, respectively, thereby altering their fluidity [116] . changes in membrane fluidity may be sensed by the immunocompetent cells, so that gene expression may be controlled according to the signals triggered. furthermore, it can be hypothesized that fluoroquinolones exert direct antiinfective activities due to their physicochemical interactions with membranes, thus making the organisms leaky, followed by cell death. this latter aspect has never been addressed systematically. any fluoroquinolone used for the treatment of bacterial infections exerts, in parallel to its antibacterial action, antiviral, antifungal, and antiparasitic actions at clinically achievable concentrations. this broad range of anti-infective activities is due to one common mode of action, i.e., the inhibition of type ii topoisomerases, thus maintaining the selective toxicity of fluoroquinolones inhibiting microbial topoisomerases and eukaryotic topoisomerases of prokaryotic origin at low concentrations but mammalian topoisomerases at much higher concentrations. there is strong evidence that the broad range of anti-infective activities translates into the clinical arena. however, anti-infective activities other than antibacterial activities have never been evaluated systematically. this may be due to the strategy of both the pharmaceutical industry and regulatory authorities to develop an agent on the basis of its application, i.e., its use as an antibacterial agent. therefore, the antiviral or antifungal activities of fluoroquinolones have, so far, not been exploited systematically; two controlled studies evaluating the antiviral effects of fluoroquinolones have been initiated recently. the clinical evaluation of their antifungal and antiparasitic effects is justifiable and would be opportune. traditionally, clinical studies are designed on the basis of a monocausal microbe-outcome association, i.e., the presence of one bacterial species at the site of infection indicates pathogenicity. consequently, an anti-infective agent is considered to be effective if this single species is eradicated from the focus of infection. however, infections may be polymicrobial or chronically ill patients may suffer from opportunistic infections; hivpositive patients represent an extreme example for the acquisition of opportunistic infections caused in parallel by viruses, bacteria, and/or parasites. such patients could, in theory, benefit from treatment with agents which exert a broad range of anti-infective activities. a multifactorial analysis of the outcome of infectious diseases would be necessary. the corresponding outcome measures are quantifiable and can be linked to pharmacokinetics and overall clinical efficacy. in summary, based on one common mode of action, fluoroquinolones being commercially available as antibacterial agents are active against viruses, fungi, and parasites too, so this class of agents is probably representative of broad-spectrum anti-infectives in its true sense. brundage rp (1962) 1,8-naphthyridine derivatives. a new class of chemotherapeutic agents inhibition by chloroquine of a novel haem polymerase enzyme activity in malaria trophozoites chloroquine: mechanism of drug action and resistance in plasmodium falciparum inhibition of glutathione-dependent degradation of heme by 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effects of quinolones antibiotics and chemotherapy. basic research and clinical aspects of pseudomonas aeruginosa the author declares that he has no conflict of interest. key: cord-281137-j81fgnld authors: rahman, lubna; shinwari, zabta k.; iqrar, irum; rahman, lutfur; tanveer, faouzia title: an assessment on the role of endophytic microbes in the therapeutic potential of fagonia indica date: 2017-08-01 journal: ann clin microbiol antimicrob doi: 10.1186/s12941-017-0228-7 sha: doc_id: 281137 cord_uid: j81fgnld background: natural products of animals, plants and microbes are potential source of important chemical compounds, with diverse applications including therapeutics. endophytic bacteria that are especially associated with medicinal plants presents a reservoir of therapeutic compounds. fagonia indica has been recently investigated by numerous researchers because of its striking therapeutic potential especially in cancer. it is also reported that endophytes play a vital role in the biosynthesis of various metabolites; therefore we believe that endophytes associated with f. indica are of crucial importance in this regard. the present study aims successful isolation, molecular identification of endophytic bacteria and their screening for bioactive metabolites quantification and in vitro pharmacological activities. methods: 16s rrna gene sequencing was used for the identification of isolated endophytic bacteria. methanolic extracts were evaluated for total phenolic contents (tpc), total flavonoids contents (tfc), dpph free radical scavenging activity, reducing power and total anti-oxidant assays were performed. and also screened for antibacterial and antifungal activities by disc diffusion method and their mic were calculated by broth dilution method using microplate reader. further, standard protocols were followed for antileishmanial activity and protein kinase inhibition. analysis and statistics were performed using spss, table curve and origin 8.5 for graphs. results: bacterial strains belonging to various genera (bacillus, enterobacter, pantoea, erwinia and stenotrophomonas) were isolated and identified. total phenolic contents and total flavonoids contents varies among all the bacterial extracts respectively in which bacillus subtilis showed high phenolic contents 243 µg/mg of gallic acid equivalents (gae) and stenotrophomonas maltophilia showed high flavonoids contents 15.9 µg/mg quercitin equivalents (qa), total antioxidant capacity (tac) 37.6 µg/mg of extract, reducing power (rp) 206 µg/mg of extract and 2, 2-diphenyl-1-picrylhydrazyl (dpph) free radical scavenging activity with 98.7 μg/ml ic(50) value. although all the extracts tested were active to inhibit growth of selected pathogenic microbes (bacteria and fungi), but significant antibacterial activity was observed against klebsiella pneumonia and b. subtilis. an enterobacter cloaca was active against leishmania tropica with ic(50) value of 1.4 µg/mg extracts. b. subtilis and bacillus tequilensis correspondingly exhibit significant protein kinase inhibition of 47 ± 0.72 and 42 ± 1.21 mm bald zones, indicating anti-infective and antitumor potential. conclusions: our findings revealed that crude extracts of selected endophytic bacteria from f. indica possess excellent biological activities indicating their potential as an important source of antibiotics (antifungal, antibacterial) compounds. drug resistance has created new health challenges for humans. over the years, emergence of new infectious diseases such as ebola, swine flu (h1n1), dengue fever and severe acute respiratory syndrome (sars), have been added to this challenges [1] . there is a general need for chemotherapeutic agents, antibiotics and pharmaceutical drugs with high effectiveness and low cytotoxicity. new medicinal agents are also needed for nematode infections such as malaria and for the treatment of parasitic protozoan diseases such as leishmaniasis and trypanosomiasis [2] . natural resources are the potential source of novel bioactive molecules and can be used in the treatment of various infections. such sources may include various forms of life like plants, marine macro-organisms (sponge, corals and algae) and endophytes (fungi, bacteria and actinomycetes) [3] . plants which are used in traditional medicines are of significant importance and therefore considerable research has been carried out on medicinal plants for bioactive compounds however limited research has been performed on the associated microorganisms. endophytes are chemical synthesizer inside plants. they play a role as a selection system for microbes to produce pharmacologically active substances with low toxicity toward mammalians [4] . endophytes are sometimes responsible for the medicinal properties of their hosts. many endophytes synthesize bioactive compounds that can be used by plants for defense against pathogens and some of these compounds may be valuable as pharmaceutical drugs [5] . fagonia indica is a small spiny shrub that belongs to the family zygophyllaceae present in warm and arid regions of the world, especially asia and africa [6] . fagonia indica is of great ethno pharmacological importance with multiple therapeutic activities such as antimicrobial, antioxidant, antiseptic, anticancer, antidiabetic and antiinflammatory [7] . the plant is also used for the treatment of fever, thirst, vomiting, asthma, urinary discharge, dysentery, liver and stomach trouble, toothache, typhoid and skin diseases [8] . this study was designed to investigate the role of endophytic bacteria in the medicinal properties of f. indica. bacteria were isolated, identified and screened for the production of bioactive secondary metabolites. all the experiments were carried out in the molecular systematics and applied ethnobotany lab, department of biotechnology, quaid-i-azam university, islamabad. the plant samples were collected in sample bags from village mullazai, peshawar, khyber pakhtunkhwa, pakistan and brought to the laboratory at the same day for the isolation of endophytic bacteria. the plant material was taxonomically identified as f. indica at the department of plant sciences, quaid-i-azam university islamabad. to further confirm the taxonomic validity of the plant species, dna barcoding was executed using cdna markes such as matk, rbcl and trnh-psba. herbarium specimen (voucher no. mosel-320) was deposited in the herbarium of molecular systematics and applied ethnobotany lab at department of biotechnology; quaid-i-azam university, islamabad. the stem of the plant was cut into pieces of about 0.5-1 cm in length and surface sterilized with 70% ethanol for 2 min followed by washing with clorox (commercial bleach) for 5 min and finally rinsing at least three to five times with sterile distilled water. stem pieces (5) (6) were blotted on the blotting paper [9] and placed on selected tryptic soy agar (tsa) media for the isolation of endophytic bacteria. the plates were incubated at 30 °c for 24 h to obtain colonies of bacteria. bacterial genomic dna was isolated using alkaline lysis method and 16s rrna gene was amplified by performing colony pcr using universal bacterial primers 27f and 1492r, which produced a product of size 1465 base pairs [10] . purification of pcr product was done by using pure linktm quick pcr purification kit (invitrogen). sanger sequencing method was used to commercially sequence the purified pcr samples with 27f primer from macrogen (south korea). sequence results obtained were compared with nucleotide sequences available on ncbi database (www.ncbi.nlm.nih.gov/blast) and also confirmed from ez-taxon (http://www.ezbiocloud.net/ eztaxon). sequences of endophytic bacteria were submitted to the genebank (ncbi) and accession numbers were obtained. selected bacterial strains were inoculated in tryptic soye broth and incubated for 48 h in shaking incubator at 30 °c at 120 rpm. bacteria were then transferred into 50 ml falcon tube and centrifuged at 10,000 rpm for 10 min. the supernatant was separated in the tube and the pellet was processed further. pellet was dissolved in organic solvent (methanol) and incubated for 1 day. next day sonication was performed to rupture the cells for 30 min after every five min. after sonication the tubes were centrifuged for 10 min at 10,000 rpm. the organic supernatant was separated in the falcon tube (a) and in the remaining pellet, again organic solvent methanol was added and centrifuged for 10 min at 10,000 rpm. supernatant was separated in the falcon tube (b). the pellet was discarded and both the solvents (a) and (b) were mixed. the solvent was evaporated at room temperature to get crude extract of bioactive metabolites. the extract was dissolved in (dimethyl sulfoxide) dmso [11] . total flavonoid contents (tfc) aluminum trichloride (alcl 3 ) colorimetric method was used for total flavonoids content determination as described by quettire-dele et al. [12] with slight modifications as per system suitability. an aliquote of 20 μl of the test sample (4 mg/ml) along with negative and positive controls i.e. dmso and quercetin (1 mg/ml) respectively were taken in 96-well plate and incubated for 30 min at 37 °c. it was followed by the addition of 10 µl of aluminum chloride (10%), 10 µl potassium acetate (98.15 g/l) and final volume was raised up to 200 µl with distilled water. absorbance was measured at 405 nm through micro plate reader (elx800biotek) and triplicate results were analyzed as µg qe/mg extracts. total phenolic contents (tpc) folin-ciocalteu method as described by jagadish et al. [13] with slight modifications was followed for tpc determination. calculated volume of test sample 20 µl was taken form 4 mg/ml stock solutions and added to 96 well plates followed by addition of 90 µl of 10 times diluted folin-ciocalteu reagent incubated for 5 min. after incubation, 6% sodium chloride solution was added to each mixture and incubated for 90 min at room temperature. dmso and gallic acid (1 mg/ml) were taken as negative and positive controls, respectively. absorbance was measured at 630 nm wave length of triplicate analysis and results were expressed in term of mean ± sd. the method described by tai et al. [14] was used for the determination of free radicals scavenging activity with minor modification. the antioxidant potential of the crude extracts was gauged by monitoring its capacity to quench the stable 2, 2-diphenyl 1-picrylhydrazyl (dpph) free radical. activated crude extract samples of bacterial endophytes i.e. 100, 50, 25 and 12.5 µg/ml were taken in 96 well plates. dpph was added to the entire row of well containing samples to obtain the final concentration of 200 µl. dmso and ascorbic acid were taken as negative and positive controls, respectively. the absorbance was measured at 630 nm using microplate reader (elx800 biotek) after 1 h of incubation at room temperature. ic 50 values expressed as µg aae/mg of extracts. percent radical scavenging was calculated by using formula: total antioxidant assay was performed to evaluate the total antioxidant capacity of extracts by phosphomolybdenum method [15] . the method depends on the reduction of mo (vi) to mo (v) by the consequent formation of a green colored phosphate/mo (v) complex with a maximal absorption at 630 nm and through antioxidant mediators [16] . reaction mixture contains 180 µl of phosphomolybdenum reagent (0.6 m h2 so4, 28 mm nah2po4, 4 mm ammonium molydate) and 20 µl of test sample taken from stock solution (4 mg/ml) followed by incubated for 90 min at 95 °c in water bath. after incubation, samples had been cooled at room temperature and transferred to 96 well plates. dmso and ascorbic acid were taken as negative and positive controls, respectively and absorbance was measure at 630 using microplate reader (elx800 biotek). results were calculated as the number of µg equivalents of ascorbic acid per mg of extract (µg/mg). the experiment was performed in triplicate. the method described by oyaizu et al. [17] was followed for the estimation of total reducing power with minor modifications. a proper volume of test samples 40 µl from the stock solution (4 mg/ml) was taken in eppendrof tubes and incubated in water bath for 20 min at 50 °c, after the addition of reagents 0.2 m phosphate buffer (6.6 ph) and 1% potassium ferri cyanide [k3fe (cn)6] (1 g 100 ml −1 ). after incubation 10% trichloroacetic acid was added to all tubes and centrifuged at 2500 rpm for 10 min. 166.66 µl supernatant from each centrifuge mixture was taken and transferred into 96 well microplate followed by the addition of 33.3 µl ferric chloride (0.1%) solution to each well and mixed properly. absorbance was measured at 630 nm through micro plate reader (elx800 biotek). results were calculated as µg aae/mg extracts of triplicate analysis. dmso and ascorbic acid were used as negative and positive controls, respectively. triplicate analysis by disc diffusion method was used to evaluate the antifungal potential of test extracts described by lai et al. [18] with some modification. crude extracts were screened against four fungal pathogenic strains: mucor mycosis (fcbp (fungal culture bank of pakistan) -0041), aspergillus flavus (fcbp-0064), aspergillus fumigates (fcbp-1264) and aspergillus niger (fcbp-0198). dimethyl sulfoxide (dmso) disc was used as negative control whereas amphotericin b was used as positive control. plates were incubated at 37 °c for 24-48 h with periodic observations of inhibition zones. extracts were screened to determine minimum inhibitory concentration bacterial extract samples were tested at lower concentration with three-fold serial dilutions and relative optical density (od) was taken at 540 nm through micro plate reader (elx800biotek). ic 50 values were obtained from the dose-response curves generated by plotting percent growth versus drug concentration. percent viable cells were calculated by using the formula. (mic) producing an inhibition zone ≥10 mm in diameter at lower concentrations ranging from 100 to 12.5 μg/disc by standard disc diffusion method. in vitro antibacterial potential of the test extracts was evaluated using 96 well microplates method as described previously by gao et al. [19] with slight modifications. the extracts were tested against gram positive bacteria: bacillus subtilis (atcc-6633), staphylococcus aureus (atcc-6538), micrococcus luteus (attc-10240) and gram negative bacteria: escherichia coli (atcc-15224), salmonella typhi (atcc-14028) pseudomonas aeruginosa (atcc-9721) and klebsiella pneumonia (atcc-4619). bacterial strains were inoculated in 10 ml tsb and incubated for 24 h at 37 °c at 120 rpm in shaking incubator. for each bacterial strain, a standardized inoculum (1 × 10 8 cfu/ml) was prepared. the test samples were used in three fold dilutions i.e. 100, 33.3, 11.1 and 3.7 µg/ml. dmso was used as negative control and cefixime monohydrate (antibiotic) as positive control, respectively. reading was initially taken at zero hours and then again after 24 h incubation through microplate reader (elx800biotek) at 630 nm wave length [20] . the corresponding 50% inhibitory concentration (ic 50 ) of each sample was calculated. the process described by ma et al. [21] was used for in vitro antileishmanial activity with slight modifications against leishmania tropica in their promastigote stage. the parasite was sub cultured in the rpmi 1640 medium supplemented, 292 µg/ml l-glutamine, 4.5 mg/ml glucose and 10% fetal bovine serum (fbs). within these culture conditions, the stationary phase of parasite growth was obtained in 6 days. the culture was incubated at 25 °c and used within 2 weeks of cultivation. antileishmanial activity of extracts in comparison to amphotericin b drug was evaluated against parasite using mtt 3-(4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide) based micro assay as a marker of cell viability. the the protein kinase inhibition assay was performed thrice with purified isolates of streptomyces 85e strain by observing hyphae formation using isp4 selective media [22] . the prepared media was subjected to autoclaving for 20 min at 121 °c and poured in the petri plates (autoclaved) under laminar flow cabinet to avoid contamination. after solidification of the media, streptomyces culture broth was spread on the surface of media with sterilized cotton swab. the test samples 20 mg/ml were tested on this media using the disc diffusion method. plates were incubated at 37 °c for 24-48 h. the zone formation was measured through vernier caliper. surfactin (antibiotic) was used as positive control while dmso as negative control, respectively. two types of zones were observed clear and bald in which the bald zones showed protein kinase inhibition activity [23] . all experiments were conducted in a completely randomized design at least three times. statistical analysis was carried out using spss 22.0 and statistic 8.1. the relationship between different parameters was assessed using pearson's correlation coefficient (r). one-way anova was used to check the significant mean difference with tukey's hsd for post hoc analysis. a p < 0.05 was used to define significant results. all the graphs were made using origin 8.1 and duncan's multiple-range test was used to find differences among treatments (p < 0.05). the isolated bacteria form (table 1) . the percent free radical scavenging activity (%rsa) of the bacterial crude extracts was evaluated by the discoloration of dpph reagent. the reaction was visible as a color change from reduction of the purple colored dpph to stable yellow-colored 2, 2-diphenyl-1-picrylhydrazyl molecule by hydrogen radical or accepting electron from donor antioxidant. results were evaluated by calculating the half maximal (50%) inhibitory concentration. it was found that s. maltophilia possess highest free radical scavenging activity with 98.7 µg/ml inhibitory concentration (ic 50 value), followed by p. dispersa and e. cloacae having 157.6 and 228.3 µg/ml ic 50 values. ascorbic acid was taken as standard and percent dpph free radical scavenging activity of each endophytic bacterial extracts are shown in table 2 . [fig. 2e (standard curve) ]. estimating total antioxidant capacity. it was found that s. maltophilia show maximum antioxidant activity among all the bacterial extracts with 37 µg/mg value followed by e. cloacae, p. cypripedi and b. subtilis with 35, 34 reducing ability was measured by change of fe 3+ to fe 2+ in reducing power assay. extracts were checked for their antioxidant reducing power. s. maltophilia and p. dispersa results indicated their electron donor ability for stabilizing free radicals and greater reductive potential with highest reducing power i.e. 206 and 175 µg ascorbic acid equivalents per mg of extract. activity of all bacterial extracts equivalent to ascorbic acid with respect to their absorbance values were shown in figs. 1d and 2c (standard curve). in antibacterial assay, all bacterial extracts show inhibition against two strains of pathogenic bacteria b. subtilis and k. pneumonia. against k. pneumonia, bacterial extracts showed ic 50 values ranging from 1 to 20 μg/ml with variable inhibition from 55 to 82 at a concentration of (100 µg/ml). while in case of b. subtilis the extracts show variable ic 50 ranging from 27 to 365 μg/ml with percent inhibition from 0 to 76. the inhibition value and effective ic 50 value of different endophytic bacterial extracts against k. pneumonia and b. subtilis were shown in (table 3) . antifungal activity of bacterial crude extracts was determined against four strains of filamentous pathogenic fungi namely; mucor mycosis, aspergillus flavus, aspergillus fumigatus and aspergillus niger through disc diffusion method. all the bacterial genera showed inhibitory activity against all the selected pathogenic fungi. almost all the bacterial extracts were active against a. niger but significant results observe are of stenotrophomonas maltophilia with 16 mm inhibitory zone and 12.5 μg/ml mic value (table 4 ; fig. 3 ). although best results showed by b. tequilensis extracts against m. mycosis with maximum zone of 12 mm and 50 μg/ml mic whereas all the extracts shows moderate antifungal activity against a. fumigatus with an average diameter of growth inhibition zone ranging from 7 to 10 mm. moreover, no inhibitory zone was observed for dmso which conform its inactivity against the selected fungal strains. although standard drug amphotericin b exhibited maximum, activity with 21.2 ± 0.985 mm zone. antileishmanial activity against promastigote was determined by mtt assay. variation was observed between bacterial extracts ( letter a-c represent; a highly significant, b slightly significant and c non-significant difference from control at p < 0.05 by one-way anova in the column * values are mean ± sd of triplicate in the current study, endophytic bacterial crude extracts were screened for the inhibition of protein kinases with streptomyces sp. the growth inhibition of streptomyces strain was used as parameter to check the cytotoxicity of endophytic crude extracts. clear zone indicates no bacterial growth having cytotoxicity while a bald zone with doted bacterial growth indicates protein kinase inhibition. in bald zone, only the hyphae formation capability of streptomyces was lost. in clear zones, complete cells were destroyed. bacterial extracts of genus bacillus show high inhibition value against streptomyces growth such as b. subtilis and b. tequilensis with 47 ± 0.72 and 42 ± 1.21 mm zone of inhibition, respectively with bald zones formation which show protein kinase inhibition activities dmso show no-toxic effect with no zone formation while positive control surfactin show the bald zone formation with 21 ± 1.02 mm ( table 6 ; fig. 3 ). a large number of bioactive metabolites with pharmacological properties have been isolated from medicinal plant's endophytes and structurally illustrated by employing various conventional as well as modern techniques. these metabolites have provided a base line for the researchers to do more work on development and formulation of bioactive compounds into useful therapies with tremendous applications in health care system and also in many other fields of human life. bacteria are common inhabitants of both internal and external tissues of most plants [12] . medicinal plants usually harbor endophytes related with their secondary metabolites and medicinal activities [5] . the present study was conducted on endophytic bacteria, isolated from f. indica with great ethno-botanical significance. it is reported that medical uses of a plant with medicinal history relates more to its endophytic population than its own biochemistry [5] . many biological assays were conducted to investigate whether bacteria associated with f. indica have potential medicinal properties. the isolated endophytic bacteria belong to diverse genera such as bacillus, enterobacter, pantoea, erwinia, stenotrophomonas as confirmed with 16s rrna gene sequence analysis. it was observed from the results that all the selected bacterial extracts exhibit various anti-bacteria, anti-fungal and protein kinase inhibition activities. antioxidants are the first line of defense against damage that may occur due to the generation of free radicals. antioxidants deactivate or stabilize free radicals before they attack the cells [24] . the free radical dpph scavenging activity model is a simple, rapid and classic method of assessing antioxidant activity [25] . methanolic extracts of endophytic isolates were able to reduce the stable radical dpph to a yellowcoloured diphenyl picryl hydrazine. among others, the culture extracts of s. maltophilia and p. dispersa showed the highest % scavenging activities which is considerable as compared to control (i.e. ascorbic acid equivalent). ic 50 value is a widely used parameter for the measurement of free radical scavenging activity. low ic 50 indicates significant activities as compared to high ic 50 value [26] . the current results are in agreement with the previous study reported by [27] , about endophytic bacteria associated with ethno-medicinal plants. oxidation in biological system is natural phenomenon resulting in the generation of highly reactive peroxyl and hydroxyl radical which may cause inadequate damage to dna, polyunsaturated fatty acid residues of cell membrane, phospholipids and proteins. it may also lead to pathological effects such as cancer and vascular diseases [28] . among the extracts total antioxidant activity of s. maltophilia was the highest followed by e. cloacae strain. reducing ability of a compound depends on the free radical scavenging capacity and electron donation [29] . endophytic bacteria isolated from centella asiatica, pantoea species such as pantoea agglomerans showed greater reductive potentials reported by rafat et al. [30] . all bacterial extracts were subjected for their reducing power but s. maltophilia and p. dispersa showed the highest values indicating their electron donating ability for table 6 protein kinase (pk) inhiation (i.e. zone's diameter in mm ± sd) during streptomyces hyphae formation of isolated bacterial extracts (bald zone indicates pk inhibition while clear zone shows cytotoxicity) surfactin stabilizing free radicals and showed the similar reductive potential as reported above. high antioxidant potential is usually related with higher proportion of the phenolic content and in the present study a significant correlation was also found in case with s. maltophili. the current results are in agreement with the previous study reported by swarnalatha et al. [31] . flavonoids have an important role in stabilizing lipid oxidation which is associated with antioxidant activity [32] . in present study highest flavonoid content was displayed by s. maltophilia culture extract which correlates with its highest radical scavenging and greatest reductive potential as discussed earlier. which are in agreement with the study reported by jalgaonwala et al. [33] about endophytic bacteria associated with host plant pongamia glabra. all isolated of endopytes extracts from f. indica showed varying degree to inhibited test organism growth but significant results were observe against k. pneumonia by each extracts. bacterial extracts of s. maltophilia, e. hormaechei, b. tequilensis and erwinia sp. also showed significant antibacterial activity against b. subtilis, with variable inhibition and ic 50 values. the crude extract of isolated b. subtilis strain showed no growth inhibition against the b. subtilis which show their similar metabolites productions and thus have no effect on test strain. moreover, extracts of all the endophytic bacteria inhibited the growth of nearly all the tested fungal pathogens. in current study the extracts producing a growth inhibitory zone ≥10 mm in agar disc diffusion assay were considered significant active. significant result was observed by s. maltophilia against a. niger with 16 mm inhibitory zone and 12.5 μg/ml mic value and b. tequilensis extracts against m. mycosis with maximum zone of 12 mm and 50 μg/ml mic. which is an agreement with the previous results reported by [34] non-toxic effect of dmso was confirmed through absence of growth inhibition zones while standard drug amphotericin b exhibited inhibitory zone of (21.2 ± 0.985). leishmaniasis, is a vector-borne disease caused by obligate intra-macrophage protozoa [35] . more investigations required to find anti-leishmanial effect by using leishmania amastigote through different in vitro assays and then to investigate in vivo activity in laboratorial infected animals which would help in obtaining a novel drug that could potentially be cost-effective against the leishmania parasite and less toxic [36] . most of the isolated endophytic bacterial crude extracts showed antileishmanial activities against leishmania tropica with ic 50 values ranging from 1.4 to 6.6 μg/ml. protein phosphorylation at threonine/serine and tyrosine residues by protein kinases is one of the major regulatory mechanisms in biological processes including cell proliferation, cell differentiation metabolism and apoptosis. deregulated phosphorylation at serine/threonine and tyrosine residues by protein kinases produced as a result of genetic alterations acquired early in tumorigenesis are often the cause of cancer. in this respect, inhibition of protein kinases has emerged as a promising target for cancer treatment [37] . using streptomyces 85e as an assay strain for kinase inhibitors appears to identify a wide range of eukaryotic kinase modulators, presumably because the streptomycete enzymes are evolutionary forerunners of their highly specific eukaryotic counterparts [38] . the growth inhibition of streptomyces strain was used as parameter to check the protein kinase inhibition of the crude extracts. bacterial extracts of genus bacillus showed high inhibition zone against streptomyces growth. b. subtilis and b. tequilensis showed bald zone formation (with 47 ± 0.72 and 42 ± 1.21 mm zone respectively), positive control surfactin also exhibit bald zone which indicate protein kinase inhibition activities. extracts were used in concentration of 100 µg/ ml while positive control with 25 µg/ml. b. subtilis is the source of surfactin antibiotic production as isolated and reported by [39] . protein kinase activity is critical for the aerial hyphae formation of streptomyces and this prerequisite has been exploited in the present study to bioprospect the extracts for their kinase inhibitory activity so that their anticancer potential could be assessed. from the preliminary study, it can be inferred that endophytes play a pivotal role in the medicinal activities of plants such as f. indica. we conclude excellent biological activities for the endophytic microorganisms associated with f. indica and postulate a viable role of the endophytic microbes in the medicinal potential of f. indica. we further recommend studies on the endophytic microbes associated with f. indica with state of the art spectroscopic and chromatographic techniques for the identification of targets and mechanism of their synthesis. hospital outbreak of middle east respiratory syndrome coronavirus thoughts and facts about antibiotics: where we are now and where we are heading fungal endophytes and bioprospecting endophytes-the chemical synthesizers inside plants bioprospecting for microbial endophytes and their natural products phytochemicals and biological activities of fagonia indica a novel steroidal saponin glycoside from fagonia indica induces cell-selective apoptosis or necrosis in cancer cells jodhpur: scientific publishers taxonomy of endophytic fungi of aerial plant tissues. microbiology of the phyllosphere selective isolation and characterization of agriculturally beneficial endophytic bacteria from wild hemp using canola endophytic fungal strains of fusarium solani, from apodytes dimidiata e. mey. ex arn (icacinaceae) produce camptothecin, 10-hydroxycamptothecin and 9-methoxycamptothecin phenolic compounds and antioxidant activities of buckwheat (fagopyrum esculentum moench) hulls and flour comparitive study on the antioxidant, anticancer and antimicrobial property of agaricus bisporus (je lange) imbach before and after boiling antioxidant activity and chemical constituents of edible flower of sophora viciifolia spectrophotometric quantitation of antioxidant capacity through the formation of a phosphomolybdenum complex: specific application to the determination of vitamin e in vitro assessment of antioxidant potential and determination of polyphenolic compounds of hedera nepalensis k. koch studies on products of browning reaction-antioxidative activities of products of browning reaction prepared from glucosamine antioxidative, tyrosinase inhibiting and antibacterial activities of leaf extracts from medicinal ferns antimicrobial and antiprotozoal activities of secondary metabolites from the fungus eurotium repens an innovative microplate assay to facilitate the detection of antimicrobial activity in plant extracts antimicrobial and antileishmanial activities of hypocrellins a and b citrinin derivatives from the soil filamentous fungus penicillium sp. h9318 evaluation of actinomycete strains for key traits related with plant growth promotion and mycorrhiza helping activities from the editor: antioxidants and diseases of the brain determination of in vitro antioxidant and radical scavenging activities of propofol assessment of phenolic content and free radical-scavenging capacity of some thai indigenous plants investigation on the bioactivity of culturable endophytic and epiphytic bacteria associated with ethnomedicinal plants total phenolic contents and free radical scavenging activity of certain egyptian ficus species leaf samples free radical scavenging activity of an aqueous extract of potato peel a novel source of bioactive compounds: endophytic bacteria isolated from centella asiatica bioactive compound analysis and antioxidant activity of endophytic bacterial extract from adhathoda beddomei coumarins as antioxidants isolation and characterization of endophytic bacterial flora from some indian medicinal plants isolation, characterization, and antimicrobial activity of endophytic bacteria from polygonum cuspidatum the leishmaniases as model zoonoses vector control in cutaneous leishmaniasis of the old world: a review of literature extraction optimization of medicinally important metabolites from datura innoxia mill: an in vitro biological and phytochemical investigation identifying protein kinase inhibitors using an assay based on inhibition of aerial hyphae formation in streptomyces studies on the biosynthesis of surfactin, a lipopeptide antibiotic from bacillus subtilis atcc 21332 we acknowledge ikram ullah (ph.d. scholar), ali talha khalil (ph.d. scholar) and tariq khan (ph.d. scholar) from department of biotechnology, quaid-i-azam university islamabad for their help and valuable advices during research work. we acknowledge molecular systematics and applied ethnobotany lab, department of biotechnology, quaid-i-azam univeristy islamabad for providing the platform to perform the experiments. authors' contributions lr participated in the overall experimental design and wrote the manuscript. zks participated in providing lab facilities and management of the study. ii and ft participated in the coordination of the study and analyzing the data sequencing. lr participated in graphical and statistical data analysis. all authors read and approved the final manuscript. the authors declare that they have no competing interests. the nucleotide genome sequences of endophytic bacteria obtained in this work were deposited in genbank under accession numbers kt367786-kt367793. it is not applicable because the manuscript does not contain anyone's individual data. this research was approved by the research ethics committee of quaid-i-azam univeristy islamabad pakistan. the work was not funded from any source and further that the institution is not providing any funds for its publication. springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. submit your next manuscript to biomed central and we will help you at every step: key: cord-318854-xaus3bma authors: sun, yi; kurokawa, masahiko; miura, motofumi; kakegawa, tomohito; motohashi, shigeyasu; yasukawa, ken title: chapter 4 bioactivity and synthesis of diarylheptanoids from alpinia officinarum date: 2016-12-31 journal: studies in natural products chemistry doi: 10.1016/b978-0-444-63601-0.00004-1 sha: doc_id: 318854 cord_uid: xaus3bma abstract many diarylheptanoids were isolated from the galangal (rhizome of alpinia officinarum). we are reported the antitumor-promoting, antiinflammatory, cytotoxic, antiinfluenza virus, and antiherpes simplex-1 virus activities of diarylheptanoids. these components in our dietary and herbal supplements are considered to be relatively nontoxic to human. in addition, we synthesized the new compounds. in this review, we discuss the antitumor-promoting, antiinflammatory, cytotoxic, antimicrobial, antiinfluenza, and antiherpes simplex-1 virus activities of diarylheptanoids isolated from galangal resulting from our own and other research groups' investigation. alpinia officinarum hance (zingiberaceae), known as lesser galangal, is a wellknown medicinal herb distributed in east asia whose rhizomes are used for stomachic, analgesic, and antiemetic treatment [1] . the plant grows several feet tall and has long leaves and reddish-white flowers. alpinia officinarum is widely cultivated throughout china, thailand, india, sri lanka, malaysia, indonesia, saudi arabia, and egypt. the species is native to asia, australia, and the pacific islands, where it occurs in tropical and subtropical climates. alpinia is the largest genus of about 230 species in zingiberaceae. historically, its rhizomes possess stimulant and digestive effects owing to their spicy flavor and aromatic scent, and as a result, it is widely used in curries and perfumes throughout asia. although it was previously used throughout europe, its use has declined in recent years, and it is now mainly used in eastern europe. homoeopaths use it as a stimulant. the rhizomes of a. officinarum have been used in traditional japanese herbal prescriptions (kampo medicine) mainly for dyspepsia, vomiting, flatulence, stomach trouble, and diarrhea. the plant is also used in traditional chinese medicine as an aphrodisiac, abortifacient, carminative, antipyretic, antiinflammatory, and emmenagogue, as well as to treat disorders of the heart and kidneys, bronchitis, chronic enteritis, renal calculus, diabetes, and rheumatism. furthermore, its rhizomes are used in various asian cuisines (for example, in thai and lao tom yum and tom kha gai soups, vietnamese hu cuisine and throughout indonesian cuisine). the rhizomes contain numerous active constituents, including essential oils [2] , resin [3] , flavonoids [4] , diarylheptanoids [5] , and phenylpropanoids [6, 7] . as the main components distributed in this genus, diarylheptanoids possess cytotoxic, antiemetic, antiinflammatory, antivirus, and antiproliferative activities. the rhizomes of a. officinarum are an important medicinal herb recorded in chinese, korean, and japanese pharmacopoeias [8] [9] [10] . in this chapter, we discuss the biological activity of natural diarylheptanoids isolated from a. officinarum, as well as synthetic diarylheptanoids. diarylheptanoids are a major class of bioactive constituents in a. officinarum that are categorized into linear, cyclic, and dimeric diarylheptanoids, or diarylheptanoids bearing special moieties ( fig. 4 .1, table 4 .1). diarylheptanoids isolated from a. officinarum are mainly linear diarylheptanoids. diarylheptanoids 2-11 mostly possess a common structural moiety of 5-ene and 3-oxo or 3,5-dioxo groups on the heptane skeleton [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] . the main types of linear diarylheptanoids (13-43) possess 5-hydroxy and 3-oxo groups in their structure [11] [12] [13] [14] [15] [16] [17] [18] [19] [22] [23] [24] [25] [26] [27] [28] [29] [30] . the other differences in structures lie in the pattern of substitution on aromatic rings. some diarylheptanoids (47) (48) (49) (50) (51) (52) (53) possess a common structural moiety of 3,5-dihydroxy on the heptane skeleton [12, 15, 17, 25, 29, 31 ]. in addition, compounds 1, 9, 12, and 44-46 are also linear diarylheptanoids that possess double bonds or ketone groups between c-1 and c-7 [15, 19, 32] . sun [14, [23] [24] [25] . several novel dimeric diarylheptanoids (58) (59) (60) (61) (62) (63) (64) were isolated from the rhizomes of a. officinarum [19, [32] [33] [34] . some dimeric diarylheptanoids were connected through cdc or cdodc bonds (58) (59) (60) (61) , and some were connected through the pyridine ring or six-numbered carbon ring (62) (63) (64) . both the pyridine and (5r)-5-(3,5,7-trihydroxyflavone)-7-(3-methoxy-4-hydroxyphenyl)-1-phenyl-3heptanone (officinin a) [35] six-numbered carbon rings are derived from the heptane unit of linear diarylheptanoids. liang et al. found that diarylheptanoid (65) has a novel skeleton bearing a flavonol moiety [35] . pharmacological research found that diarylheptanoids exhibited antiproliferative, cytotoxic, antiemetic, antiinflammatory, and antivirus activities. many related diarylheptanoids have been examined in order to study the structureactivity relationship (sar). several research groups have developed techniques for the detection, isolation, and identification of the components from a. officinarum. wong et al. isolated two diarylheptanoids (6 and 24) and two flavonoids using high-speed countercurrent chromatography (hsccc) from chloroform extracts [36] . ho et al. attempted to analyze the ethyl acetate extract directly by high-performance liquid chromatography (hplc) with photodiode array and electrochemical detection (hplc-ecd) techniques [37] . the hplc-edc method is also a very powerful tool for the detection of diarylheptanoid components at the nanogram level. furthermore, feng et al. discussed the separation and identification of diarylheptanoids in supercritical fluid extracts of a. officinarum using a uplc-q-tof-ms-ms system [38] . diarylheptanoids are widely distributed in nature. curcumin is the most common diarylheptanoid and possesses a range of bioactivities against human diseases, including antitumor, antiinflammatory, and antioxidant activities [39] . on the other hand, yashabushidiols were isolated from the male flowers of alnus sieboldiana (betulaceae) by hashimoto et al. [40] , and these compounds are also included in the diarylheptanoids from a. officinarum, such as compound (49) (fig. 4.2) . stereoselective synthesis of yashabushidiols and their derivatives has been reported by venkateswarlu's group, shinde's group, and yikang's group [41] [42] [43] . each group used a sugar or derivative as a starting material; for example, d-mannitol, d-glucose, and d-gluconolactone. after several steps, acetal compounds were obtained, and nucleophilic addition or wittig reactions then afforded yashabushidiols and their derivatives ( fig. 4.3) . we also synthesized yashabushidiols and their derivatives using kinetic resolution of sharpless asymmetric epoxidation reaction [44] (fig. 4.4) . first, 4-phenyl-1-butyne was treated with n-buli followed by addition of 3-phenylpropionaldehyde to a lithiated alkynyl solution. reduction of propargyl alcohol with red-al afforded the racemic allylic alcohol. sharpless epoxidation reaction of allylic alcohol gave enantio-enriched antiepoxy alcohol through kinetic resolution, followed by reduction using red-al to afford both natural and unnatural types of yashabushidiol b (49) . on the other hand, racemic allylic alcohol was treated with mcpba and preferentially generated syn-epoxy alcohol followed by reductions using cp 2 ticl 2 , zn, and zncl 2 to afford yashabushidiol a. compounds 35 and 32, and their enantiomers, were synthesized under almost the same conditions. compound 32 showed particularly strong antiviral activity against respiratory syncytial virus (rsv) in vitro and in vivo [44] . optically active compounds 35 and 32 were synthesized from racemic allylic alcohols according to the following procedure. first, kinetic resolution of optically active epoxy alcohol and chiral allylic alcohol was performed by sharpless asymmetric epoxidation (sharpless ae). chiral allylic alcohol was subjected to sharpless ae with l-dipt to afford the opposite configuration epoxy alcohol. these epoxy alcohols were then oxidized by dess-martin periodinane oxidation to afford optically active α-epoxy ketones. finally, compound 35 and its enantiomers were obtained by treating β-hydroxy ketone with meotf and 2,6-di-tert-butylpyridine; deprotection of β-hydroxy ketone by tbaf yielded compound 32 (fig. 4.5) . compound 50 was also isolated from a. officinarum. it resembled the structure of yashabushidiol b, which was synthesized by das et al. [45] . they also used kinetic resolution of sharpless ae reaction with the racemic allylic alcohol, followed by a ring opening reaction. the 3,5-dihydroxy compound was protected by 2,2-dimethoxypropane under acid conditions, followed by deprotection of the pmb group using ddq reagent. finally, the terminal hydroxyl group was oxidized by swern oxidation to afford aldehyde compound, and it was then subjected to wittig reaction followed by reduction using h 2 and pd on carbon to yield compound 50 ( fig. 4.6 ). alpinoids b (46) and c (45) were also isolated from a. officinarum by sun et al. [18] . both compounds have a unique moiety in the skeleton of the γ-hydroxy-α-enone carbon chain. generally, diarylheptanoids possess 3,5-diketo, 3-keto-5-hydroxy, or 3-keto-4-ene structures, but alpinoids b (46) and c (45) have a 3-keto-4-ene-5-hydroxy moiety. in addition, there is a chiral center at c-5, and its absolute configuration was determined as r by mosher's method. alpinoid c (45) and its analogues were synthesized by venkateswarlu's group and miura's group [46, 47] . the synthetic strategy of venkateswarlu's group is described below (fig. 4.7) . first, 4-phenyl-2-buten-1-ol was treated with (+) dipt, ti(oipr) 4 , and cumene hydroperoxide to afford chiral epoxy alcohol. after two further steps, epoxy alcohol formed chiral allylic alcohol followed by olefin metathesis coupling using grubb's second generation catalyst to afford alpinoid c (45) . on the other hand, miura et al. synthesized 45 using asymmetric 2,3-sigmatropic rearrangement of chiral α-sulfinyl enone ( fig. 4.8 ). chiral α-sulfinyl enone was readily synthesized from l-menthyl sulfinate [48] . chiral α-sulfinyl enone treated with catalytic amount of dbu and pph 3 , followed by oxidation with aqueous h 2 o 2 solution afforded target compound 45 in high enantiomeric excess. neuroblastoma is a common extracranial pediatric solid tumor, accounting for 10% of all tumors in the pediatric age group. the clinical presentation of neuroblastoma is variable and advanced cases are often found to be highly resistant to conventional treatment modalities based on surgery, chemotherapy, transplantation, and radiotherapy [49] . thus, development of new effective and safe therapeutic agents for the treatment of neuroblastoma is urgently needed. in a recent publication, we discussed the antitumor activity of naturally occurring compounds against neuroblastoma [50] . compounds 6, 24, and 30 exhibited the most potent activity against neuroblastoma imr-32 cells (table 4. 2), with ic 50 values of 0.11, 0.83, and 0.23 μm, respectively [17] , and were more potent than cisplatin (ic 50 : 0.85 μm). sun et al. found that diarylheptanoids containing the substituents of 3″-ome and 4″-oh on the benzene ring or only a carbonyl (c-3) and a double bond (c-4/5) at the aliphatic chain possessed potent cytotoxicity against the imr-32 cell line [17] . dose-dependent manner. they found that 5 induces s phase arrest and apoptosis via upregulation of activating transcription factor 3 (atf3) and stabilization of p53 in the shsy5y cell line [25] . compound 5 also exhibited potent cytotoxicity against hepg2, mcf-7, and sf-268 (atcc) human cancer cell lines (ic 50 : 6-10 μg/ml) [24] . furthermore, matsuda et al. also tested the inhibition of melanogenesis by 6, 21, 24, and 49 in theophylline-stimulated b16 melanoma 4a5 cells, and found ic 50 values of 10-48 μm. compound 6 showed the strongest activity among the four diarylheptanoids (ic 50 : 10 μm), and it also inhibited the mrna expression of tyrosinase, tyrosinase-related protein (trp)-1 and trp-2, as well as protein levels of microphthalmia-associated transcription factor (mitf) [52] . chronic inflammation may be a causative factor in a variety of cancers. the longer the inflammation persists, the higher the risk of cancer. in general, inflammatory leukocytes such as neutrophils, monocytes, macrophages, and eosinophils provide soluble factors that are thought to mediate the development of inflammation-associated cancer, including the cancer cells themselves, although other cells also participate. inflammatory mediators include metabolites of arachidonic acid, cytokines, chemokines, and free radicals. chronic exposure to these mediators leads to increased cell proliferation, mutagenesis, oncogene activation, and angiogenesis. emphasis will be placed on examining the role of the reactive oxygen (eg, o 2 − ) and nitrogen intermediates (eg, no), cytokines (eg, interferons, interleukins, tumor necrosis factor-α (tnf-α)), and prostaglandins (pgs). increased cancer incidence is associated with increased duration of inflammation. animal models have demonstrated experimentally that chronic inflammation can lead to the development of various forms of cancer, while providing further insights into possible mechanisms. skin tumors are induced by administration of carcinogens such as 7,12-dimethylbenz[a]anthracene (dmba), followed by repeated administration of tumor promoters such as 12-o-tetradecanoylphorbol-13-acetate (tpa) [53] . in recent publications, we discussed the inflammatory and tumor promotion, and its inhibitors from naturally occurring compounds [54, 55] . methanol extracts from the rhizomes of a. officinarum inhibited tumor promotion by tpa after initiation with dmba in icr mice [56] . fig. 4 .9a shows the percentage of tumor-bearing mice treated with dmba plus tpa was 80% at week 20, whereas that in the group treated with dmba plus tpa and methanol extract of a. officinarum was 20%. treatment with methanol extracts of the rhizomes of a. officinarum caused an 85% reduction in the average number of tumors per mouse at week 20 ( fig. 4 .9b). using bioassay-guided isolation, seven diarylheptanoids (2, 4, 6, 21, 24, 30, and 35) were isolated from active fractions of the methanol extracts of a. officinarum [56] . the inhibitory effects against tpa-induced inflammation closely paralleled those of the inhibition of tumor promotion in two-stage carcinogenesis initiated by dmba and tpa, a well-known tumor promoter, in a mouse skin model [57] . these diarylheptanoids inhibit tumor promotion in two-stage carcinogenesis in mouse skin. on the other hand, these diarylheptanoids inhibited tpa-induced inflammation in mice (table 4. 3). compounds 4 and 30 were similar in activity to indomethacin, an inflammatory drug [56] . the antiinflammatory mechanisms of diarylheptanoids have been reported by many researchers. matsuda et al. found that compounds 6, 21, 24, and 49 inhibited nitric oxide (no) production in lipopolysaccharide (lps)-activated mouse peritoneal macrophages on bioassay-guided isolation, and compound 6 showed particularly strong inhibitory activity with an ic 50 value of 33 μm [58] . bioassay-guided purification of ether extracts led to the isolation of a new diarylheptanoid (44) , as well as two known diarylheptanoids (2 and 17) . these compounds exhibited potent platelet-activating factor (paf) receptor binding inhibitory activity with ic 50 values of 1.3, 5.0, and 1.6 μm, respectively [16] . compound 15 also showed inhibitory and bactericidal activities against enteropathogenic escherichia coli (epec) clinical isolates and efficiently suppressed epec lps-induced inflammation in human peripheral blood mononuclear cells [59]. compound 6 exhibited antiinflammatory properties in a mouse macrophage cell line (raw 264.7) (6.25-25 μm) and suppressed lps-induced production of no, interleukin (il)-1β, and tnf-α by inhibiting nuclear factor-κb (nf-κb) activation and phosphorylation of p44/42 mitogen-activated protein kinases (mapks) [60] . compounds 2, 6, 15, 16, 47, and 48 were tested for their inhibitory effects on no production in the lps-activated macrophage cell line raw 264.7 [15] . compounds 6 and 2 showed potent inhibitory activities with ic 50 values of 0.6 and 6.8 μm, respectively. diarylheptanoid 3, isolated from the n-hexane extract, modulated nf-κb signaling involved in the inflammatory response, and inhibited lps-induced expression of tnf-α, il-1β, nitric oxide synthase (nos), and cyclooxygenase-2 (cox-2) at the gene level in raw 264.7 cells [21] . kiuchi et al. examined the effects of diarylheptanoids (6, 11, 13-15, 19, and 40) against pg and leukotriene. this suggested that compounds lacking the methoxy group adjacent to the phenol were less active than those possessing the methoxy group, presumably owing to the decrease in acidity from the phenol group [26, 28] . thus, the reports cited above suggest that diarylheptanoids possess inhibitory effects against inflammatory and tumor-promoting activities. diarylheptanoids exhibited antiviral activities against influenza virus [61] [62] [63] [64] [65] , rsv [44, 66] , poliovirus [44] , measles virus [44] , herpes simplex virus type 1 (hsv-1) [44] , human immunodeficiency virus (hiv) [67] , severe acute respiratory syndrome (sars) virus [68] , and epstein-barr virus in relation to carcinogenesis [69] . they are characterized as compounds possessing broad antiviral spectrum against dna and rna viruses. most diarylheptanoids possessing antiviral activities have been evaluated in vitro. antiviral activities in vivo have been documented for influenza virus and rsv using animal infection models [62, 65, 66] . sawamura et al. [61, 62] examined the antiinfluenza virus activity and cytotoxicity of 10 diarylheptanoids (2, 4, 6, 21, 24, 30, 32, 35, 36, and 49) isolated from a. officinarum by plaque reduction assay and mtt assay, respectively, using madin-darby canine kidney (mdck) cells (table 4 .4). in this study, influenza virus was more susceptible to 6 (ec 50 = 2.9 ± 0.3 μg/ml) and 32 (ec 50 = 0.7 ± 0.2 μg/ml) than to the others, and their therapeutic indexes (cc 50 / ed 50 ) were 11.7 and 114.3, respectively [61] . compound 32 has a 4-hydroxylphenyl moiety. platyphyllone and platyphyllone-5-xylopyranoside contain two 4-hydroxyphenyl moieties and have been reported to be active against influenza virus with therapeutic indexes of >10 [64] . thus, hydroxylation at the c-4 position of the phenyl moiety may be important for antiinfluenza virus activity in vitro. however, in a murine influenza virus infection model, 6 significantly reduced virus titers in bronchoalveolar lavage fluids of the lungs and prolonged survival times of the infected mice without toxicity, whereas 32 did not show this activity [62] . compound 6 possessed an unsaturated ketone and a methoxy group at the c-5 position of the 4-hydroxyphenyl moiety, but 32 did not. thus, the ketone and methoxy groups may be necessary for antiinfluenza activity in vivo. compound 6 exhibited antiviral activity against h1n1 virus, h3n2 virus, and b type virus, as well as oseltamivir-resistant h1n1 virus [62] . this indicates that the mode of antiinfluenza virus action of 6 was different from that of the known agents, such as oseltamivir, and suggests that it is a candidate antiviral compound against more virulent strains than the pandemic h1n1. in fact, 6 was shown to have no effect on virus adsorption or invasion into cells, instead suppressing the expression of viral messenger rna and antigens in infected mdck cells [62] . it is probable that 6 selectively suppressed influenza virus mrna synthesis in infected cells without cytotoxicity [62] . diarylheptanoids isolated from alpinia katsumadai such as katsumadain a and (e,e)-5-hydroxy-1,7-diphenyl-4,6-heptadien-3-one are reported to have inhibitory activity against the neuraminidase (na) of influenza virus (a/pr/8/34) in vitro [65] . some diarylheptanoids isolated from a. officinarum may therefore be effective in reducing na activity. konno et al. [34, 84] (table 4 .4). among these, 6 and 30 were not effective against the a2 strain of rsv [84] . the ec 50 values of 4 and 66 were 5.0 ± 0.0 and 7.0 ± 1.4 μg/ml (table 4 .4), respectively, and both compounds showed antiviral activity against the a2 strain of rsv with therapeutic indexes of 4.6 and 14.3, respectively, and were more potent than the other tested compounds [44, 66] . compound 4 was also active against influenza virus with an ec 50 value of <10 μg/ml [61] , which suggests that 4 is an effective diarylheptanoid against both rsv and influenza virus in vitro. compounds 22 and 22/32 were synthesized as an enantiomer and racemate, respectively, of 32, and compound 66 was synthesized as the enantiomer of 35 (fig. 4.10 ) [44] . the therapeutic indexes of stereoisomers (22, 32 , and 22/32) were similar (cc 50 /ec 50 : 1.3, 2.1, and 3.4, respectively) and their ec 50 values were 44.7 ± 1.5, 40.7 ± 3.5, and 24.3 ± 0.6 μg/ml (table 4 .4), respectively [44] . however, the therapeutic indexes of 35 and 66 (6.1 and 14.3) were higher than those of the three stereoisomers, with the ec 50 values of 16.3 ± 3.5 and 7.0 ± 1.4 μg/ml, respectively [44, 66] . the c-5 position of 35 and 66 is methoxylated with a saturated ketone at the c-3 position. compound 30 also contained a methoxy group with a saturated ketone and its ec 50 value was 13.3 ± 3.8 μg/ml [66] . thus, methoxylation in diarylheptanoids may contribute to anti-rsv activity in vitro. in a murine intranasal rsv infection model, compounds 22, 32, 22/32, and 66 were significantly effective in reducing virus titers, infiltration of lymphocytes and interferon-γ levels (marker of pneumonia severity) in the lungs of mice [44] . among these, 66 showed the strongest anti-rsv activity in mice, as shown by anti-rsv assay in vitro, and this may be a lead compound for the development of anti-rsv drugs in the future. six diarylheptanoids (2, 6, 21, 24, 30, and 35) were examined for their anti-rsv activity against poliovirus, measles virus, and hsv-1 by plaque reduction assay and trypan blue dye exclusion assay using vero cells (table 4 .4). among the six compounds, 6 and 30 did not exhibit any significant anti-rsv activity in hep-2 cells [84] . however, 30 exhibited relatively stronger antiviral activities against all three viruses (poliovirus, measles virus, and hsv-1), but 6 was only effective against measles virus. all the examined diarylheptanoids except 6 exhibited antipoliovirus activity with ec 50 values between 3.7 ± 0.6 and 44.3 ± 4.0 μg/ml, and all except 2 and 6 exhibited anti-hsv-1 activity with ec 50 values between 5.7 ± 0.6 and 58.7 ± 1.5 μg/ml (table 4 .4). all six examined compounds were significantly effective against measles virus with ec 50 values between 6.3 ± 0.6 and 47.0 ± 4.6 μg/ml. thus, diarylheptanoids appear to have a broad spectrum of antiviral activity. chareonkla et al. [67] reported that (3s,5s)-3,5-diacetoxy-1,7-bis(3,4,5-trimethoxyphenyl) heptane from zingiber mekongense exhibited anti-hiv activity in the antisyncytium assay using δtat/rev mc99 virus and 1a2 cell line system, but that it did not show activity on hiv-1 reverse transcriptase assay. hirsutenone isolated from alnus japonica has been shown to be a potent inhibitor of papain-like protease, which controls replication of the sars coronavirus. this compound is therefore thought to be a potential compound for the treatment of sars [68] . some cyclic diarylheptanoids isolated from acer nikoense and myrica rubra are reported to strongly inhibit epstein-barr virus early antigen activation in raji cells, and they also exhibit inhibitory activities on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test [69] . it is possible that some diarylheptanoids from a. officinarum possess antiviral activity against these viruses. obesity is a major health concern at present and is widely considered to be a global epidemic. conventional or allopathic medicines used to treat obesity have high abuse potential and frequently exhibit side effects. few botanicals included in natural weight loss products have been thoroughly researched on a basic or clinical level, and it is thus imperative to validate their widespread consumption for weight management. many natural weight loss products are sold and used globally with little or no proof of efficacy and quality, and concerns regarding safety have surfaced with good reason. orlistat inhibits pancreatic and gastric lipases that catalyze the hydrolysis of ingested fats, resulting in reduced dietary fat absorption and high fecal fat excretion [70] . it is certain that orlistat has a marked drug effect, as 35-45% of energy intake in western diets is attributed to dietary fat. however, malabsorption of fat leads to rather uncomfortable side effects, such as flatus with discharge, oil spotting from the rectum, fecal incontinence, fecal urgency, loose or liquid stools, and malabsorption of fat-soluble vitamins [70] . the water extract of rhizomes from a. officinarum showed the strongest inhibitory activity against pancreatic lipase in vitro. the extract was subsequently fractionated using organic solvents, and the ethyl acetate fraction had the strongest inhibitory activity. the most potent inhibitor in this fraction was identified as galangin-3-methyl ether (fig. 4.11) with an ic 50 value of 1.3 mg/ ml, as compared with the positive control (orlistat) with an ic 50 value of 0.8 mg/ml using triolein as the substrate. after oral administration of corn oil, triglyceride levels in mice decreased significantly to less than those in the control group by administration of h 2 o extract (1 g/kg) and the ethyl acetate fraction (0.5 g/kg). in triton wr-1339-induced hyperlipidemic mice, galanin-3-methyl ether significantly decreased triglyceride and cholesterol levels at a 20 mg/kg dose to 81.3% and 81.0%, respectively, while it increased high density lipoprotein (hdl) when compared with the control group. moreover, galanin-3-methyl ether did not show hypolipidemic activity in high cholesterol dietinduced hyperlipidemic mice [71] . compound 15 exhibited inhibitory activity against pancreatic lipase with an ic 50 value of 1.5 mg/ml using triolein as the substrate. the levels of serum triglyceride in corn oil fed mice were reduced significantly, while the levels of serum triglyceride and cholesterol were reduced in triton wr-1339-induced hyperlipidemic mice. hypolipidemic activity was not observed in the high-cholesterol diet-induced hyperlipidemic mice. inhibition of pancreatic lipase for both compounds when compared with the positive control (orlistat) was good in terms of other parameters, such as triglyceride, cholesterol and hdl levels. however, orlistat remained the most effective drug [72] . antiemetic drugs are effective against vomiting and nausea and may be used for severe cases of gastroenteritis, particularly if the patient is dehydrated. antiemetics can also be used for morning sickness, but there is little information about their effects on the fetus. some crude drugs inhibit vomiting among traditional japanese herbal prescriptions, while a. officinarum is used as an antiemetic in traditional chinese medicine. takahashi et al. reported that diarylheptanoids showed antiemetic activities in a copper sulfate (cuso 4 )-induced emesis assay in young chicks [12, 29] . the sar of diarylheptanoids was also investigated. among 14 diarylheptanoids, two types of essential functional structure showed inhibitory activities against emesis. diarylheptanoids 2, 4, 6, 21, 22, 24, 27 contained partial type a or b structures ( fig. 4.12) , and they therefore concluded that diarylheptanoids of types a and b might be the main antiemetic components of a. officinarum. 5α-reductase (reduced nicotinamide adenine dinucleotide phosphate: δ 4 -3-ketosteroid 5α-oxidoreductase), which is present as type 1 and type 2 isozymes in humans and rats, catalyze the reductive conversion of testosterone to 5α-dihydrotestosterone [73] . 5α-dihydroteststerone acts as a more active androgen than testosterone in many tissues, such as the prostate. therefore, inhibitors of this enzymatic conversion may be useful in the selective treatment of androgen-dependent diseases, such as benign prostate hyperplasia, male pattern baldness, and acne. most 5α-reductase inhibitors are steroids binding to the steroid receptors, and these steroids may produce various undesirable hormonal effects acting as agonists or antagonists. it has been reported that diarylheptanoids possess inhibitory activity against 5α-reductase. the sar of four diarylheptanoids (2, 22, 24, and 31) from a. officinarum was discussed [13] . it has been suggested that diarylheptanoids with unsaturated bonds, particularly the conjugated form in the alkyl structural moiety between the two aryl groups, had weak inhibitory activity, while diarylheptanoids with saturated counterpart bonds had potent inhibitory activity. thus, the alkyl parts of the diarylheptanoids appear to be important structural moieties for inhibitory activity against 5α-reductase. helicobacter pylori is a gram-negative, microaerophilic bacterium found in the stomach. it is also related to the development of duodenal ulcers and stomach cancer [74] . the eradication of h. pylori is effective in preventing duodenal ulcers and stomach cancer. lee et al. examined the inhibitory effects of compound 15 against h. pylori atcc 43504, atcc 700392, and atcc 700824 using the paper-disc diffusion and agar dilution methods [75] . rhizome-derived materials, particularly isolated diarylheptanoids, merit further study as potential antipylori functional food products or therapeutic products for preventing the diseases caused by h. pylori. zhang [19] . the ic 50 values of these compounds were 9-20 μg/ml and 25-47 μg/ml against hp-sydney and 1 hp-f44 strains, respectively. from bacteria to vertebrates, cells change their patterns of gene expression to respond to their microenvironment. in addition to classical dna microarray technology (transcriptome analysis), new analytical tools for high-throughput screening of whole transcriptome sequencing, polysome profiling (translatome analysis [76] ) or ribosome profiling (ribosome protection assay [77] ) have recently emerged and been applied to the analysis of gene expression (fig. 4 .13) [78] . in et al. reported that microarray global gene expression analysis showed 1′s-1′-acetoxyeugenol acetate (fig. 4.14) , a novel phenylpropanoid from alpinia conchigera, enhanced the apoptotic effects of paclitaxel in mcf-7 cells through nf-κb inactivation [79] . this suggests that the induction of tumor cell death through apoptosis is modulated through dysregulation of the nf-κb pathway. as genetic information transforms from dna to proteins, the cellular abundance of proteins is predominantly controlled at the translation level [80] . weak correlations between messenger rna (mrna) and protein levels [81] are observed because nontranslated mrnas may be present in rna granules, rna particles, processing bodies, stress granules, and mirna-risc (mirisc) complexes in cytosol (fig. 4.13) . analysis of the translatome can thus provide substantial and surprising new information [82] . whole free polysome and/or membrane-bound polysome analysis has also been applied. ribosome-associated mrnas (usually >3) are separated from mrnas associated with fewer ribosomes. these polysome-associated mrnas are applied to label probes on dna microarrays (translatome analysis) or are sequenced using next-generation sequencers (polysome profiling). these polysome-associated mrnas are then applied to ribosome-protection assay, and the resulting segments of rna are sequenced using next-generation sequencers (ribosome profiling). in these analyses, active and stalled ribosomes have been shown to cosediment during isolation of polysome complexes through sucrose gradients [83] , thus indicating that polysome profiling does not fully distinguish translationally active from repressed mrnas. diarylheptanoids 6, 24, and 30 inhibit proinflammatory mediators and exhibit cytotoxic and antiviral activities. however, the precise mechanisms of action and their effects on expression of specific genes are unknown. thus, we used translatome analysis to investigate the mechanisms and modes of action of these diarylheptanoids [84] . polysome-associated mrnas were prepared from diarylheptanoid-treated and control cells from a human b lymphoblastoid cell line; these mrna samples were then used for microarray analysis. the number of downregulated inflammatory-related transcripts was ranked as follows: 30 > 24 > 6. compound 6 showed greater influence on the translatome of bjab cells, while 24 showed less efficacy, except when upregulating the expression of genes related to rhodopsin-like gpcrs, mrna processing, and proteasomerelated proteins of wikipathways [85] . it is possible that the same host factors, such as splicing factors or hnrnps listed in mrna processing wp411 45374 (wp; wikipathways), affect virus structure and/or replication. sixteen transcripts were upregulated after treatment with 6, 24, or 30. among these, transcripts of heterogeneous nuclear ribonucleoprotein c (c1/c2), heterogeneous nuclear ribonucleoprotein k, non-pou domain containing, octamer-binding, and polypyrimidine tract-binding protein 1 were identified as internal ribosome entry site trans-acting factors. all of these studies have provided new insights into the mode of action of diarylheptanoids from a. officinarum with regard to its antiinflammatory, antitumor promotion, and antiviral effects. humans have used plants as foods and natural medicines since ancient times, and while they are crude drugs, are typically safer than synthetic drugs, and have been used as both spices and supplements. several active components have been isolated, and their chemical structures have been and continue to be determined. the diarylheptanoids of the rhizomes of a. officinarum are considered to be a particularly promising group of compounds. diarylheptanoids are minor but ubiquitous components in our diet and have the advantage of being nontoxic or relatively nontoxic to humans. natural diarylheptanoids have multiple physiological functions, including antiinflammatory, antitumor, cancer preventive, antiviral, antiemetic, and anti-pylori effects. challenges that must be overcome in order to find functionally useful compounds that can be applied clinically are further screening of natural diarylheptanoid compounds, examination of sars, elucidation of physiological action mechanisms, and the problems associated with supplying large quantities of compounds. in order to resolve these issues, collaboration between researchers in various fields will be necessary. activator protein-1 atf3 activating transcription factor 3 bjab the human b-lymphoma cell line encyclopedia of herbs & their uses studies in natural products chemistry chinese pharmacopoeia of the people's republic of china the korea food and drug administration notification, korean pharmacopoeia the japanese pharmacopoeia drug discovery research in pharmacognosy drug discovery and development -from molecules to medicine key: cord-011038-5t8az1hf authors: mor, satbir; sindhu, suchita title: synthesis, type ii diabetes inhibitory activity, antimicrobial evaluation and docking studies of indeno[1,2-c]pyrazol-4(1h)-ones date: 2019-10-26 journal: med chem res doi: 10.1007/s00044-019-02457-8 sha: doc_id: 11038 cord_uid: 5t8az1hf we report a convenient and efficient synthesis of indeno[1,2-c]pyrazol-4(1h)-ones (4a‒o) by the reaction of a variety of 2-acyl-(1h)-indene-1,3(2h)-diones (1) and 2-hydrazinylbenzo[d]thiazole/2-hydrazinyl-6-substitutedbenzo[d]thiazoles (2) in the presence of glacial acetic acid in good yields. the structure of the compounds thus prepared were confirmed by analytical and spectral (ft-ir, (1)h nmr, (13)c nmr, and hrms) techniques. all the synthesized indeno[1,2-c]pyrazol-4(1h)-ones (4a‒o) were assayed for their in vitro type ii diabetes inhibitory activity by using acarbose as standard drug and in vitro antimicrobial activity utilizing streptomycin and fluconazole as reference drugs. among the synthesized derivatives, 4e (ic(50) = 6.71 μg/ml) was found to be more potent against α-glucosidase enzyme as compared with the standard acarbose (ic(50) = 9.35 μg/ml) and 4i (ic(50) = 11.90 μg/ml) exhibited good inhibitory activity against α-amylase enzyme as compared with the standard acarbose (ic(50) = 22.87 μg/ml). also, all the titled compounds showed good antimicrobial activity. in addition, in vitro α-glucosidase and α-amylase inhibition were supported by docking studies performed on the derivatives 4e and 4o, respectively. [image: see text] diabetes mellitus is a metabolic disorder resulting from inadequate secretion of insulin characterized by chronic hyperglycemia caused by high calorie diets rich in fat, carbohydrates and proteins . the international diabetes foundation (idf) reports that there were 425 million diagnosed cases of diabetes globally in 2017 which is estimated to increase to 629 million by 2045. recently, there are more than 46 million diabetics in north america and the caribbean, 58 million in europe, 26 million in south and central america, 39 million in middle east and north africa, 16 million in africa and 82 million in south-east asia. there are 352 million people at the risk of developing type ii diabetes (idf diabetes atlas 2017). the emerging factors that contribute to the spread of type ii diabetes, comprising a progressively technological society, food habits with high calorie diets rich in fats and carbohydrates, and an increasingly inactive lifestyle (wagman et al. 2017) . type ii diabetes is associated with hypertension, dyslipidemia, obesity, cardiovascular disease, etc. it may also eventually cause tissue or vascular damage leading to severe diabetic complications such as retinopathy, neuropathy, and nephropathy (keri et al. 2015) . out of several enzymes known, α-amylase and α-glucosidase are the key enzymes in the lowering of postprandial hyperglycemia observed in case of type ii diabetes mellitus (t2dm) (patil et al. 2013) . α-amylase inhibits dietary starch from being absorbed into the body system and leads to lowering of blood glucose by the inhibition of salivary and pancreatic amylase (ajiboye et al. 2016) . α-glucosidase inhibitors have been reported to reduce postprandial hyperglycemia in diabetic mellitus resulting in the lowering of glucose absorption by carbohydrate digestion and increases digestion time (chaudhry et al. 2017) . likewise, the emergence of bacterial resistance of pathogenic microorganisms is rapidly becoming a major worldwide problem . therefore, the demand for new antimicrobial agents is necessary, but now days, it leads to a challenging task for chemists to synthesize new molecules with excellent activity (kim et al. 2012) . in the recent years, indeno-fused heterocycles are recognized as important frameworks with a broad spectrum of pharmacological properties. among them, indenopyrazoles have gained substantial attention due to their wide range of biological activities such as antitubercular (ahsan et al. 2011) , tyrosine kinase inhibitors , cns agents (lemke et al. 1978) , antioxidant activity , non-steroidal anti-inflammatory drugs (lemke et al. 1989) , anticancer (mor et al. 2016) , antimicrobial , anti-hiv and anticonvulsant activities (ahsan et al. 2012) , and cyclin-dependent kinase (cdk) inhibitors (singh et al. 2006) . moreover, methyl 3-((6-methoxy-1,4dihydroindeno [1,2-c] pyrazol-3-yl)amino)benzoate was the first indenopyrazole that was reported as a tubulin polymerization inhibitor (minegishi et al. 2015) . similarly, benzothiazole is a privileged bicyclic ring system associated with numerous pharmacological activities like antitumor (gabr et al. 2015) , anticonvulsant (amnerkar and bhusari 2010) , antimicrobial (chugunova et al. 2015; kamal et al. 2015) , antihelmintic (sarkar et al. 2013) , antileishmanial (keri et al. 2015) , antitubercular (patel et al. 2013) , anti-inflammatory (shafi et al. 2012) , antipsychotic (yevich et al. 1986 ), antioxidant (bhat and belagali 2016), antidiabetic (meltzer-mats et al. 2013; kamal et al. 2015) activities, etc. some of the important marketed drugs involving benzothiazole nucleus are riluzole, sibenadet hydrochloride (viozan), and pramipexole (scott and njardarson 2018) . zopolrestat is another significant drug containing benzothiazole core with antidiabetic effects (carvalho et al. 2006) . to the best of our knowledge as revealed by literature surveys , none of hetrocycles with indenopyrazole skeleton have been reported to exhibit antidiabetic effects. therefore, we thought of synthesizing some new benzothiazole tethered indenopyrazoles to see the additive effect of these moieties towards the preliminary examination of in vitro antidiabetic activity (doddaramappa et al. 2015) . in this perspective and in continuation of our interest in the synthesis of heterocycles containing nitrogen (zhou et al. 2017; huang and huang 2019) and sulfur as heteroatoms and their biological activities herein, we report the synthesis, characterization, α-amylase and α-glucosidase inhibition, antimicrobial evaluation and docking studies of several benzothiazole tethered indeno [1,2-c] pyrazol-4(1h)ones (4a-o). all reagents were used without any further purification. melting points were observed using electrothermal melting point apparatus, labco co., india and are not corrected. the ft-ir spectra were recorded in kbr on ir affinity-1 ftir (shimadzu) spectrophotometer, and results are reported in cm −1 . 1 h nmr and 13 c nmr spectra were recorded on bruker avance iii nmr spectrometer operating at 400 and 100 mhz, respectively, with cdcl 3 as the solvent and tetramethylsilane (tms) as the internal standard. chemical shifts (δ) are reported in parts per million (ppm), and coupling constants (j) are expressed in hertz (hz) . hrms were obtained from waters synapt g2-si qtof and sciex 5600 + qtof mass analyser by using the electrospray ionization (esi) method. the purity of synthesized compounds was checked by precoated tlc plates (sil g/uv 254 , alugram) using a mixture of hexane and ethyl acetate as eluent and visualization was achieved via uv light. general procedure for the synthesis of 2-acyl-(1h)indene-1,3(2h)-diones (1) 2-acyl-(1h)-indene-1,3(2h)-diones (1) needed for the purpose were prepared via claisen condensation of diethylphthlate and appropriate aliphatic ketones in presence of freshly prepared sodium methoxide following the procedure presented in literature (mor et al. 2016 thiazol-2-amines thus obtained was filtered through suction and washed with hexane. thereafter, the salt was dissolved in water upon warming and the product was precipitated by adding dil. naoh solution. the solid thus formed was filtered through suction and recrystallized from ethanol to afford the corresponding amines in high yields . to a solution of hydrazine hydrochloride in ethylene glycol was added the appropriate benzo[d]thiazol-2-amine/6-substitutedbenzo[d]thiazol-2-amines in portions with continuous stirring and the resulting mixture was heated to reflux on a heating mantle for 2 h. a fine crystalline solid was separated out on cooling which was filtered, washed with water and crystallized from rectified sprit to yield the corresponding 2-hydrazinylbenzo[d]thiazole/2-hydrazinyl-6-substitutedbenzo [d]thiazoles (2) in good yields ). general procedure for the synthesis of benzothiazolyl hydrazones (3) a solution of equimolar quantities of 2-acyl-(1h)-indene-1,3 (2h)-diones (1, 3 mmol) and hydrazines (2, 3 mmol) in dry methanol (15 ml) was heated on a water bath for 15 min in presence of catalytic amount of glacial acetic acid (4-5 drops). thereafter, reaction mixture was cooled at room temperature. the solid thus separated out was filtered through suction and recrystallized from ethyl acetate-ethanol to give the corresponding benzothiazolyl hydrazones (3a-o) as orange solids (sawhney and lemke 1983; . general procedure for the synthesis of indeno [1,2-c] pyrazol-4-ones (4a-o) benzothiazolyl hydrazones (3) were charged with glacial acetic acid (30 ml) and heated to reflux on a heating mantle for 7-9 h till the completion of reaction as indicated by tlc. the reaction mixture was cooled at room temperature and the solid thus obtained was filtered, and recrystallized from chloroform to furnish the target compounds 4a-o in good yields. the physical and spectral data of compounds 4a-o are as follows: 1-(benzo[d]thiazol-2-yl)-3-methylindeno [1,2-c] 122.83, 124.09, 124.29, 124.54, 125.45, 126.75, 130.69, 132.58, 133.32, 133.58, 140.10, 148.70, 150.95, 158.73, 184.34 (c-4) 121.49, 122.38, 123.97, 124.27, 124.54, 128.26, 130.64, 132.63, 133.45, 133.57, 135.73, 140.16, 143.67, 148.56, 148.94, 158.58, 184.38 (c-4) ; hrms: m/z (m + ) cacld. for c 19 h 13 n 3 os: 331.0779, found: 332.0839 [m+h] + . j = 7. 28 hz, ; 13 c nmr (100 mhz, cdcl 3 ): δ = 21.15 (-ch(ch 3 ) 2 ), 28.14 (-ch(ch 3 ) 2 ), 118.70, 123.11, 123.90, 124.23, 124.34, 130.22, 130.79, 132.63, 133.53, 134.99, 140.02, 144.69, 149.89, 159.39, 159.55, 159.83, 183.74 (c-4) 2 ), 27.79 (-ch 2 ch(ch 3 ) 2 ), 36.32 (-ch 2 ch(ch 3 ) 2 ), 121. 63, 122.79, 123.98, 124.24, 124.43, 125.39, 126.69, 130.62, 132.67, 133.34, 133.53, 140.13, 148.32, 150.93, 152.78, 158.81, 184 .14 (c-4); hrms: m/z (m + ) calcd 119.77, 120.95, 121.95, 123.88, 125.12, 127.58, 128.98, 130.64, 132.01, 139.18, 140.27, 148.66, 150.06, 151.58, 154.85, 159.83, 182.64 (c-4) 56, 115.82, 123.45, 123.83, 124.28, 124.41, 127.13, 130.61, 132.79, 133.55, 134.79, 136.96, 140.30, 145.23, 150.48, 152.66, 158.00, 184.23 (c-4) 120.97, 121.36, 121.49, 123.57, 124.37, 124.47, 127.28, 127.54, 130.78, 133.58, 140.09, 149.54, 151.28, 152.08, 153.03, 158.93, 185.16 (c-4) 123.85, 123.92, 124.24, 124.37, 124.47, 130.00, 130.46, 132.55, 133.57, 134.15, 140.09, 149.88, 150.21, 153.04, 159.80, 184.05 (c-4) in vitro α-glucosidase inhibition mccue's protocol was followed for evaluation of in vitro αglucosidase inhibitory activity, with some modifications (mccue et al. 2005) . the present activity was carried by using α-glucosidase enzyme (saccharomyces cereviciae). a solution of the enzyme was obtained by adding 20 μl αglucosidase (0.5 unit/ml) in 120 μl of 0.1 m phosphate buffer (ph 6.9). in microplate wells, the enzyme solution was mixed with 10 μl of each test samples which, in turn, were prepared by dissolving in dimethylsulphoxide (dmso) at various concentrations i.e. 12.5, 25, 50, 100 μg/ ml and incubated for 15 min at 37°c. thereafter, this was charged with 20 μl of substrate solution to 5 mm p-nitrophenyl-α-d-glucopyranoside in 0.1 m phosphate buffer (ph 6.9) and further incubated for 15 min. a solution of 0.2 m sodium carbonate (80 μl) was added to terminate the reaction, and absorbance was measured at λ = 405 nm on elisa microplate reader. the reaction system without test samples (4a-o) was used as control while the system without α-glucosidase was used as a blank, and acarbose was used as positive control. each experiment was performed in triplicate. the enzyme inhibitory rates of samples have been expressed as percentage (%) inhibition which is determined by eq. (1) as follows: the ic 50 values of compounds 4a-o were calculated. the protocol reported by xiao et al. and yoshikawa et al. with slight modifications was utilized for the evaluation of in vitro α-amylase inhibition activity (xiao et al. 2006; yoshikawa et al. 2001) . stock solutions of compounds 4a-o were prepared by dissolving the compound (5 mg) in dmso (5 ml) at room temperature. the α-amylase inhibitory activity was examined at different concentrations of each sample i.e., 12.5, 25, 50, and 100 μg/ml. the reagent solution without the test sample was used as the control and acarbose was used as standard reference. substrate solution was prepared by dissolving soluble starch (500 mg) in 0.4 m naoh (25 ml) and heated for 5 min at 100°c. after cooling in ice cold water, the ph of the solution was achieved to 7 by adding 2 m hcl, and water was added to make the volume to 100 ml. the sample (20 μl) and substrate (40 μl) solutions were mixed in a microplate well and the mixture in each case was preincubated at 37°c for 3 min. thereafter, 20 μl of α-amylase solution (50 μg/ml) was added to each well, and the microplate was incubated for 15 min. the reaction was terminated by adding 0.1 m hcl (80 μl). then 1 mm iodine solution (200 μl) was added to the reaction mixture and absorbance was measured at λ = 650 nm with elisa microplate reader. the enzyme inhibitory activity expressed as percentage (%) inhibition was calculated by eq. (2) as follows: where, abs1 = absorbance of incubated solution containing test sample, starch and amylase, abs2 = absorbance of incubated solution containing test sample and starch, abs3 = absorbance of incubated solution containing starch and amylase, and abs4 = absorbance of incubated solution containing starch. all the synthesized compounds 4a-o were screened for their antibacterial activity using agar well diffusion method (okeke et al. 2001) . the test microorganisms were enthused by inoculation in 25 ml of nutrient broth (peptone 5 g/l, sodium chloride 5 g/l, hm peptone 1.5 g/ l, yeast extract 1.5 g/l, ph = 7.4 ± 0.2). the media was solidified and the test bacterial strains were cultivated by pour plate method on nutrient agar plates. wells were bored in the seeded agar plates by using sterile cork borer of 8 mm diameter and these were loaded with a 100 μl of each synthesized compound reconstituted in dmso. all the plates were incubated at 37°c for 24 h. the diameter of inhibition zone of the test organisms was measured by using digital colony counter (lab and life instruments pvt. ltd., india) and reported in mm. sterile dmso was used as a negative control, whereas streptomycin was used as a positive control. the experiments were performed in triplicates and the mean values are reported. antifungal activity of the title compounds 4a-o was examined against a. niger by a quantitative microspectrophotometric assay (broekaert et al. 1990 ) in 96-well microplates. the growth inhibition was observed at 595 nm. initially, the fungus was grown on potato dextrose broth (pdb) (potatoes, infusion form = 200 g/l, dextrose = 20 g/ l, ph = 5.1 ± 0.2 at 25°c) at 27°c for 7 days. the spores of the fungus were collected from culture on broth plates. the sporangial suspension concentration was measured by hemocytometer and made to 1.7 × 10 5 spores/ml and the fungal spore suspension was stored at −40°c. the pdbfungal spore suspension solution was prepared by mixing pdb (25 ml) with 0.147 ml of the fungal spore suspension solution. experiment was performed with 100 μl of each of the compounds 4a-o to be assayed and 100 μl of pdbfungal spore suspension solution. dmso was used as a negative control and fluconazole was used as a positive control. after incubation at 27°c for 48 h, growth was observed by measuring absorbance at 595 nm on elisa plate reader. growth inhibition was reported by using eq. (3) given as follows: where a control is the absorbance of the control and a sample is the absorbance of the tested microculture. molecular docking analysis was performed using autodock vina in autodock tools (trott and olson 2010) . for αglucosidase (pdb id: 5nn5), the coordinates of center of grid box were center_x = −16.224, center_y = −35.668 and center_z = 95.439, the size of grid box was x_size = 24 å, y_size = 24 å and z_size = 24 å, and the exhaustiveness was equal to 40. for α-amylase (pdb id: 2qv4), the coordinates of center of grid box were cen-ter_x = 20.074, center_y = 46.866 and center_z = 29.866, the size of grid box was x_size = 28 å, y_size = 28 å and z_size = 28 å, and the exhaustiveness was equal to 40. structures of the newly synthesized compounds 4a-o were confirmed by their ft-ir, nmr ( 1 h and 13 c), and mass spectra. their ft-ir spectra exhibited strong absorption bands at 1585-1608 (c=n) and 1693-1716 (c=o) cm −1 . the main characteristic feature of 1 h nmr spectra of derivatives 4a-o is the resonance of a signal appeared as a doublet integrating for one proton in the range of δ 8.03-8.56 ppm, (j = 7.28-8.00 hz), which was safely assigned to 8-h. downfield shifting of this proton is probably due to anisotropic-diamagnetic effect of lone pair of electrons present on nitrogen/sulfur of benzothiazole moiety, which finds support from the results reported earlier (mor et al. 2016) . the significant feature of 13 c nmr spectra of compounds 4a-o demonstrated the downfield shifting of signal due to c-4 (carbonyl carbon) which was observed in the region at δ 182.64-185.16 ppm. however, the remaining protons in 1 h nmr and carbons in 13 c nmr spectra displayed signals in the expected regions. further, the hrms analysis results were found in consistent with their molecular formulae (vide experimental). in search of new antidiabetic agents, we recognized primarily various pyrazole derivatives as reported in the literature (wright et al. 1964) . to the best of our knowledge, this is the first report of antidiabetic activity possessed by synthesized indeno [1,2-c] pyrazol-4-ones (4a-o). all synthesized compounds 4a-o were assessed for their αglucosidase inhibitory activity against α-glucosidase enzyme (saccharomyces cerevisiae) at various concentrations ranging from 12.5 to 100 μg/ml following the developed earlier procedure (mccue et al. 2005 ) by using acarbose as the standard (table 1) . it is inferred from the data presented in table 1 that all the derivatives exhibited moderate to excellent % inhibition against α-glucosidase enzyme as compared with the standard. compound 4i was found to be more potent analogue of this series with 67. 02, 86.27, 90.47, and 94 .52% inhibition when explored at the concentrations of 12.5, 25, 50, and 100 μg/ml, respectively. similarly, compound 4e exhibited a rise in % inhibition from 76.41 to 82.76% on increasing the concentration from 12.5 to 50 μg/ml in comparison to the standard drug acarbose. compound 4l displayed 90.78% inhibition followed by 4a that exhibited 87.26% inhibition at concentration of 100 μg/ml. among the synthesized indeno [1,2-c] pyrazol-4-ones, 4e and 4i were found to be more active with ic 50 values 6.71 and 8.18 μg/ml, respectively (acarbose ic 50 = 9.35 μg/ml). however, the derivatives 4a and 4b exhibited good inhibitory activity with ic 50 values 9.87 and 10.59 μg/ ml, respectively. scheme 1 synthesis of indeno [1,2-c]pyrazol-4-ones (4a-o) in vitro α-amylase inhibitory activity the α-amylase inhibitory activity of the synthesized compounds 4a-o was screened following xiao's procedure (xiao et al. 2006; yoshikawa et al. 2001 ) by using acarbose as the standard reference ( table 2) . the results of the α-amylase inhibitory activity depicted in table 2 revealed that all the tested derivatives 4a-o displayed moderate to high % inhibition. compounds 4a, 4e, 4i, 4l, and 4o at concentration 12.5 μg/ml, 4e, 4f, 4i, 4l, and 4o at concentration 25 μg/ml, and 4a and 4o at concentration 50 μg/ml were found to be more potent than the standard. whereas compound 4i displayed inhibition equivalent to the standard drug acarbose at concentration 100 μg/ml. the analogues 4c and 4j at concentration 12.5 μg/ml, 4a and 4d at concentration 25 μg/ml, 4b, 4d, 4e, and 4i at concentration 50 μg/ml, and 4a and 4c at concentration table 1 in vitro α-glucosidase inhibitory activities of indeno [1,2-c] 100 μg/ml demonstrated comparable inhibitory activity as shown by the standard drug acarbose. furthermore, the remaining compounds were found to display lesser inhibitory activity as compared with the standard drug screened at different concentrations. among the synthesized derivatives, 4a (ic 50 = 21.23 μg/ml), 4e (ic 50 = 19.25 μg/ml), 4i (ic 50 = 11.90 μg/ ml), and 4o (ic 50 = 12.83 μg/ml) demonstrated higher activity than the standard (acarbose, ic 50 = 22.87 μg/ml). consequently, 4a, 4e, 4i, and 4o can be considered as a possible antidiabetic agent for further studies. structure activity relationship (sar) for antidiabetic activity of indeno [1,2-c] pyrazol-4-ones (4a-o) according to the presented data for antidiabetic activity of indeno [1,2-c] pyrazol-4-ones (4a-o), the following sars have been established: (1) results of antidiabetic activity indicated that the presence of r 1 = ch 3 and r 2 = h, br in the synthesized compounds 4a-o has led to increase the antidiabetic activity against α-glucosidase enzyme while the derivative 4e containing r 1 = ch 3 and r 2 = br has been found to exhibit improved inhibitory activity against α-amylase enzyme. (2) compound 4i containing r 1 = i-propyl and r 2 = cl has been found to enhance inhibitory activity against both α-glucosidase and α-amylase enzymes. (3) derivative 4l containing r 1 = i-butyl and r 2 = ch 3 has improved inhibitory activity against α-glucosidase, whereas presence of r 1 = i-butyl and r 2 = br in compound 4o had increased inhibitory activity against α-amylase enzyme. from these results, it is inferred that the compounds containing r 1 = ch 3 and r 2 = h, ch 3 , och 3 , cl, and br, are found to display more inhibitory activity against αglucosidase as compared with the remaining derivatives containing r 1 = i-propyl and i-butyl, and r 2 = h, ch 3 , och 3 , cl, and br, whereas no such trend was observed against α-amylase inhibitory activity. overall, we may conclude that there are different structural requirements for a compound to be effective against α-glucosidase and αamylase enzymes. however, no general trend for sar was established for both α-glucosidase and α-amylase enzymes. the above mentioned findings are summarized in fig. 1 . all synthesized indeno [1,2-c] pyrazol-4-ones (4a-o) were tested for their in vitro antibacterial activity against grampositive (b. subtilis, s. aureus) and gram-negative (e. coli, p. aeruginosa) bacteria by agar well diffusion method using streptomycin as the reference drug (table 3 ) (okeke et al. 2001) . it is revealed from the data presented in table 3 that compound 4l and 4g exhibited the highest activity against b. subtilis, while the derivative 4h demonstrated maximum inhibition zone against s. aureus. moreover, the analogues 4f and 4j displayed moderate activity against e. coli, while 4g demonstrated activity against p. aeruginosa. on the other hand, some compounds were inactive against the specific bacteria under study. overall, these results suggest that the synthesized compounds 4a-o exhibit lesser activity against the bacterial strains than standard drug streptomycin. all synthesized compounds 4a-o were evaluated for their in vitro antifungal activity against a. niger by the quantitative microspectrophotometric assay using fluconazole as the standard drug (broekaert et al. 1990) (table 4) . a perusal of accumulated data from table 4 reveals that all synthesized compounds 4a-o were found to inhibit fungal growth with inhibition ranging from 49.21 to 72. 25%, 54.71 to 76.96%, 59.42 to 80.89%, and 67.01 to 84.55% at concentration 125, 250, 500 , and 1000 μg/ml, respectively. derivative 4o was found to be more active with ic 50 value of 5.68 μg/ml than the standard (ic 50 = fig. 1 structure activity relationship (sar) for antidiabetic activity of synthesized indeno [1,2-c] pyrazol-4-ones (4a-o) table 3 in vitro antibacterial activity of indeno [1,2-c] 11.75 ± 1.50 sars for antimicrobial activity of indeno [1,2-c] pyrazol-4ones (4a-o) the sars approach to the synthesized derivatives 4a-o demonstrated good to moderate inhibitory potential against all the microbial strains under study. consequently, we may conclude that there are different structural requirements for a compound to be effective against different bacterial and fungal strains. moreover, no general trend has been established for the sars for antimicrobial activity. molecular docking analysis of some selected synthesized compounds with enzymes α-glucosidase and α-amylase was performed to find out the mechanism of action at the molecular level. crystal structure used for α-glucosidase was obtained from protein data bank and the pdb id for this structure is 5nn5 (roig-zamboni et al. 2017) . docking protocol was validated by docking the co-crystallized ligand. in vitro assay showed that compounds 4e and 4i exhibit best α-glucosidase inhibitory potential, hence molecular docking analysis was performed using these two compounds. compound 4e with a docking score of −7.3 showed three pi-pi interactions with amino acid residue phe-525, trp-376 (t shaped), and trp-481 (t shaped) as shown in fig. 2 and hydrophobic interactions with trp-481 and phe-649. compound 4i with docking score of −8.4 showed interactions very similar to that of 4e i.e., three pi-pi interactions with amino acid residue phe-525, trp-376 (t shaped), and trp-481 (t shaped) as shown in fig. 3 and further stabilizing interactions are provided by hydrophobic contacts with asp-282, ala-555, and phe-649. both the compounds were found to bind in similar orientation with a snug fit. in vitro results showed that most of the synthesized compounds 4a-o were stronger inhibitors of α-amylase compared with acarbose. compounds 4i and 4o showed superior inhibition as compared with the other synthesized compounds. therefore, 4i and 4o compounds were used for determining the binding pose and interactions responsible for the activity against human pancreatic α-amylase (pdb id: 2qv4) (maurus et al. 2008) . first docking protocol was validated by performing docking of co-crystallized ligand. compound 4o with docking score of −8.8 was found to be showing two hydrogen bond interactions with amino acid residues gln-63 and thr-163, three pi-pi interactions with trp-59 and hydrophobic contacts with tyr-62, leu-162, and leu-165. the binding pose of compound 4o is shown in fig. 4 . compound 4i with docking score of −9.3 binds in active site of α-amylase with orientation and interactions similar to that of 4o. it is showing one hydrogen bond with gln-63, one halogen bond with asp-197, three pi-pi interactions with trp-59 and hydrophobic contacts with trp-58 and tyr-62 as shown in fig. 5 . in conclusion, the present study describe the synthesis and characterization of heterocyclic frameworks i.e., indeno [1,2-c] pyrazoles (4), and their biological evaluation as inhibitor of α-glucosidase and α-amylase related to type ii diabetes, and antimicrobial activity. the chemistry for the synthesis of indeno [1,2-c] pyrazole (4) involved the reaction of 2-acyl-(1h)-indene-1,3(2h)-diones (1) (3), which upon subsequent refluxing in glacial acetic acid afforded the target compounds 4 in good yields. some of the synthesized compounds exhibited significant in vitro αglucosidase and α-amylase inhibitory activity viz. 4e was found to be more potent with ic 50 value 6.71 μg/ml against α-glucosidase enzyme and 4i showed good activity with ic 50 value 11.90 μg/ml against α-amylase enzyme as compared with reference drug acarbose (ic 50 = 22.87 μg/ml). moreover, some of the compounds exhibited convincing results for antimicrobial activity, however, with a degree of variation. the antidiabetic activity was found to be more prolific than antimicrobial activity. in vitro α-glucosidase and αamylase inhibition was further supported by docking studies of compounds 4e, 4i, and 4o. hopefully, these findings will prove helpful to medicinal chemists for the development of new inhibitors of enzymes related to type ii diabetes. publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. c=n stretch), 1716 (c=o stretch), 2918, 2962 (aliphatic c-h stretch), 3086 (aromatic c-h stretch) cm −1 ; 1 h nmr (400 mhz c=n stretch), 1712 (c=o stretch), 2920, 2962 (aliphatic c-h stretch), 3089 (aromatic c-h stretch) cm −1 ; 1 h nmr (400 mhz 3089 (aromatic c-h stretch) cm −1 ; 1 h nmr (400 mhz -isopropylindeno[1,2-c]pyrazol-4 (1h)-one (4f): yellow solid 3057 (aromatic c-h stretch) cm −1 ; 1 h nmr (400 mhz 44 hz, 8-h); 13 c nmr (100 mhz -methylbenzo[d]thiazol-2-yl)indeno[1,2-c] pyrazol-4(1h)-one (4g): yellow solid; yield 67% cdcl 3 ): δ = 1.42 (6h, d, j = 6.92 hz, -ch(ch 3 ) 2 , 2.51 (3h, s, ch 3 ), 3.08-3.14 (1h, m, -ch(ch 3 ) 2 ) yellow solid; yield 65%; mp 212-214°c; ftir (kbr): ν max 759 (1h)-one (4i): yellow solid; yield 70%; mp 182-184°c; ftir (kbr): ν max 763, 1109, 1381, 1500, 1544, 1597 (c=n stretch), 1703 (c=o stretch), 2870, 2964 (aliphatic c-h stretch), 3086 (aromatic c-h stretch) cm −1 ; 1 h nmr (400 mhz ar-h), 8.46 (1h, d, j = 7.40 hz, 8-h) hrms: m/z (m + ) calcd -isopropylindeno[1,2-c] pyrazol-4(1h)-one (4j): yellow solid; yield 65%; mp 190-194°c; ftir (kbr): ν max 738 3062 (aromatic c-h 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evaluation and qsar studies of some 3-aryl-1-heteroarylindeno [1,2-c]pyrazol-4 (1h)-ones synthesis of indane-based 1,5-benzothiazepines derived from 3-phenyl-2,3-dihydro-1h-inden-1-one and antimicrobial studies thereof synthesis, biological evaluation, and molecular docking studies of some n-thiazolyl hydrazones and indenopyrazolones synthesis, type ii diabetes inhibitory activity, and antimicrobial tests of benzothiazole derivatives bridged with indenedione by methylenehydrazone evaluation of extracts of the root of landolphia owerrience for antibacterial activity synthesis of coumarin-based 1,3,4-oxadiazol-2ylthio-n-phenyl/benzothiazolyl acetamides as antimicrobial and antituberculosis agents synthesis, crystal structure and antidiabetic activity of substituted (e)-3-(benzo[d]thiazol-2-ylamino) phenylprop-2-en-1-one structure of human lysosomal acid α-glucosidase-a guide for the treatment of pompe disease synthesis of 1-[2(substituted phenyl)-4-oxothiazolidin-3-yl]-3-(6-fluro-7-chloro-1,3-benzothiazol-2-yl)-ureas as anthelmintic agent analysis of us fda-approved drugs containing sulfur atoms chemistry of β-triketones. 1. structure of schiff base intermediates of 2-acyl-1,3-indandiones synthesis of novel 2-mercaptobenzothiazole and 1,2,3-triazole based bis-heterocycles: their anti-inflammatory and anti-nociceptive activities design, synthesis, and antimicrobial evaluation of 1,4-dihydroindeno[1,2-c]pyrazole tethered carbohydrazide hybrids: exploring their in silico admet, ergosterol inhibition and ros inducing potential 3d-qsar comfa study on indenopyrazole derivatives as cyclin dependent kinase 4 (cdk4) and cyclin dependent kinase 2 (cdk2) inhibitors autodock vina: improving the speed and accuracy of docking with a new scoring function, efficient optimization, and multithreading synthesis, binding mode, and antihyperglycemic activity of potent and selective (5-imidazol-2-yl-4-phenylpyrimidin-2-yl)[2-(2-pyridylamino)ethyl] amine inhibitors of glycogen synthase kinase 3 the antidiabetic activity of 3,5-dimethylpyrazoles a quantitative starch-iodine method for measuring alpha-amylase and glucoamylase activities synthesis and biological evaluation of 1-(1,2-benzisothiazol-3-yl) and (1,2-benzisoxazol-3-yl) piperazine derivatives as potential antipsychotic agents polyphenol constituents from salacia species: quantitative analysis of mangiferin with α-glucosidase and aldose reductase inhibitory activities design, synthesis and biological activity of pyrazinamide derivatives for anti-mycobacterium tuberculosis conflict of interest the authors declare that they have no conflict of interest. key: cord-328834-yetnlb2j authors: mohsin, noor ul amin; irfan, muhammad; hassan, shams ul; saleem, usman title: current strategies in development of new chromone derivatives with diversified pharmacological activities: a review date: 2020-06-15 journal: pharm chem j doi: 10.1007/s11094-020-02187-x sha: doc_id: 328834 cord_uid: yetnlb2j chromone derivatives possess a spectrum of biological activities. chromone has been recognized as a privileged structure for new drug invention and development. substitution pattern of chromone scaffold determines different type of biological activities. the type, number and position of substituents connected to the chromone core play a vital role in determining pharmacological activities. in the present review, we have discussed new chromone derivatives as anticancer, anti-diabetic, antimicrobial, anti-inflammatory, antioxidant and as anti-alzheimer agents. this review deals with the chromone derivatives prepared by combining chromone molecule with various natural and synthetic pharmacophores and pharmacological activities presented by them. the main aim is to highlight the diversified pharmacological activities exhibited by chromone hybrid molecules during the last eight to ten years. chromone is a heterocyclic compound containing oxygen as heteroatom and has a benzo-g-pyrone skeleton (fig. 1, compound 1 ). chromone is a natural molecule present in the diet of human and animals and shows less toxicity to mammalian cells [1] . chromone containing natural and synthetic molecules displayed interesting biological activities [2] . medicinal properties exhibited by chromone derivatives are antibacterial, antifungal, antioxidant, antimalarial, neuroprotective and hiv inhibitory potential [3 -8] . chromone derivatives have also shown promising anticancer and antiviral potential [9 -13] . anti-inflammatory, antiallergenic and antiulcer are other properties displayed by chromone derived molecules [14 -16] . chromone is treated as an attractive source for the synthesis of new drugs due to its valuable activities and low toxicity [17] . chromone is considered as a single molecule which can combine with different types of receptors [18] . modifications of chromone scaffold have been performed at benzene or pyrone ring by attachment of different substituents. 3-formylchromone (fig. 1, compound 2) is a frequently used precursor for the synthesis of chromone derivatives and can be prepared easily by the vilsmeir -haack reaction [19] . chromone derived molecules have been discussed with respect to chemical structures, pharmacological activities and structure -activity relationship (sar) in following sections. cancer is a serious problem all around the world due to high mortality and there is demand to discover new leads as anticancer agents [20] . a number of anticancer drugs have been discovered from natural sources [21] . chromone derived molecules have displayed excellent anticancer activities. amin and co-workers synthesized new molecules by merging benzofuran and 5h-furo [3,2g] chrome-5-one and attached different heterocyclic rings through sulfonamide group. these compounds displayed in vitro activity against breast cancer cell line (mcf-7) ranging from 0.004 -0.87 mm. compound 3 (fig. 2) presented prominent in vitro activity (ic 50 = 0.056 ± 0.0027 mm) against mcf-7 cell line in comparison to standard drug (doxorubicin, ic 50 = 0.62 ± 0.0316 mm) and proved less toxicity to normal cell line (ic 50 = 23 ± 1.02 mm). these derivatives also showed p38a mapk (mitogen-activated protein kinase) inhibition activity. mapk controls many biological functions such as cell growth, differentiation and inflammation [22] . molecular docking studies showed that compound 3 formed four hydrogen bonds with k-53, m-109 and g-170 amino acids of mapk [23] . singh, et al. attached indole, pyrimidine, pyrazole with chromone to produce new derivatives. it was observed that introduction of 2,6-dichlorophenyl, 2,6-dichlorobenzoyl group along with indolinone produce notable activities. compound 4 manifested prominent in vitro antitumor activity with 50 -90% growth inhibition of all tumor cell lines and showed an average gi 50 value of 3.2 mm. compound 4 was more potent against leukemia (rpmi-8226 gi 50 [24] . synthesis of chromone and sulfonamide comprising molecules was carried out by awadallah, et al. in which two molecules were linked to each other by a large heterocyclic ring or by small linker groups such as methine amine or alkyl amine. compound separated by small linker group dispensed greater activity. upon in vi-tro evaluation, compound 5 emerged as the most active against breast (mcf-7, ic 50 = 0.72 mm) and lung (a-549, ic 50 = 0.50 mm) cancer cell lines as compared to doxorubicin (mcf-7 ic 50 = 33.13 ± 2.90 mm, a-549 ic 50 = 26.81 ± 2.50 mm). compound 5 presented selectivity for isoforms ix and xii of the human carbonic anhydrase (hca). this compound induced apoptosis in both types of cancer cell. it was also observed that compounds having free sulfonamide group presented higher activity. when the sulfonamide group was attached with heterocyclic scaffold such as pyridine, pyrimidine, and isoxazole, less active derivatives were obtained [25] . chen, et al. attached chromone molecule to 1-alkyl-1h-imidazole-2-yl via dienone as linker group. the nitrogen-containing heterocycles were used as bioisostere for phenols in the natural compound while the dienone linker was used as substitute for dienone in curcumin. compound 6 presented excellent activity against prostate cancer (pc-3, ic 50 = 1.8 ± 0.3 mm and lncap ic 50 = 1.0 ± 0.2 mm) cell lines. the nitrogen atom of imidazole carries ethyl group. replacement of ethyl group by longer chain has no significant influence on anticancer activity. therefore they are excellent molecules for future investigations [26] . dolatkhah, et al. used the three-component reaction involving chromone-3-carboxaldehyde, alkyl acetoacetate, urea or thiourea to produce 4h-chromone-1,2,3,4tetrahydropyrimdine-5-carboxylates using mcm-41-so 3 h nanoparticles as catalyst. the catalyst can be recycled and reused. compound 7 presented prominent activity against leukemia cell line upon evaluation by microculture tetrazolium test (mtt) assay. this compound showed no toxicity to normal cell line human foreskin fibroblast (hu02). compound 5 showed high affinity (binding energy = -10.10 kcal/mol) with ab1-kinase enzyme by autodock-4 program [27] . nam, et al. developed chromone derived analogues of lavendustin. upon anticancer evaluation, compounds 8 (ic 50 = 6.01 ± 2.7 mm) and 9 (ic 50 = 9.92 ± 3.6 mm) showed prominent activities against a-549 cell line. compound 8 (ic 50 = 6.89 ± 2.6 mm) and 9 (ic 50 = 7.86 ± 2.2 mm) also showed activity against hct-15 cell lines. in compound 8, replacement of 4-methoxybenzyl with benzyl or phenethyl decreased the activity. in compound 9, replacement of 4-nitrobenzyl with 4-methoxybenzyl or benzyl group produced less active compounds against hct-15 cell line [28] . bhatia and co-workers synthesized chalcone-chromenone derived molecules. upon in vitro evaluation, compound 10 ( fig. 3) showed prominent activity (87% growth inhibition) against colon cancer cell line (hct-116) as compared to fluorouracil (67% inhibition). compound 10 carries two halogen atoms each on the chromone core and chalcone fragment [29] . ozen, et al. conjugated chromone molecule with 5-membered heterocyclic scaffolds thiazolidindiones, imidazolidindiones and thiohydantoins to produce new hybrid molecules. compound 11 showed prominent activity against liver (huh-7 ic 50 = 5.2 mm) and breast cancer (mcf-7, ic 50 = 4.9 mm) cell lines. this compound contains unsubstituted chromone while ethyl group is attached with thiohydantoin. when the chromone ring is substituted with methyl group, resultant compound showed less activity. compound 11 did not show apoptosis but only reduced the replication of cells [30] . singh and co-workers synthesized chromenopyridine derivatives based on the activity of chromones and pyridones. derivatives bearing electron withdrawing groups at positions # 5, # 6 and # 7 of chromone scaffold showed better activity. compound 12 appeared as the most potent against pc-3 (ic 50 = 2.4 ± 3.4 mm), mcf-7 (ic 50 = 10.7 ± 2.5 mm) and hela (ic 50 = 7.0 ± 3.5 mm) cancer cell lines. this compound contains allyl group attached to pyridone and showed better activity as compared to unsubstituted compounds [31] . obreque-balbua and coworkers synthesized chromone derivatives as abcc1 modulators. an amino or carboxamide group was introduced at position # 2. abcc1 overexpression is detected in different types of cancers. compound 13 was the most effective (ic 50 = 11.3 ± 1.8 mm) in reducing the abcc1 mediated resistance in comparison to reversan (ic 50 = 4.3 ± 0.2 mm). derivative 13 showed selectivity for abcc1 over abcg2 and abcb1. it consists of chromone molecule connected to benzo [1, 2, 5] oxadiazole via piperazine linker group. insertion of carbonyl group between chromone and piperazine decreased the activity [32] . abdelhafez at al. synthesized benzofuran derivatives as vascular endothelial growth factor (vegf) inhibitor. bromovisnagin (14) was an intermediate product and consist of chromone core in its structure. bromovisnagin (14) showed prominent anticancer (ic 50 = 3.67´10 -7 -7.65´10 -13 mm) potential as compared to other products in this series. compound 14 was the most potent agent against mcf-7 (ic 50 = 3.67´10 -7 ) as compared to standard drug epirubicin (ic 50 = 2.22´10 -9 ). docking studies of compound 14 with vegfr2 (vascular endothelial growth factor receptor) kinase enzyme showed hydrogen bonding between furan oxygen and amino group of d1046. methoxy group showed interaction with nh moiety of k868 [33] . chand and colleagues synthesized substituted chromone, 4-oxo-4h-1-benzopyran derivatives as anticancer agents. compounds having acrylate group at position # 3 demonstrated prominent activity. derivatives having amide and acid group at this position proved less active. compound 15 was the most active (50 -60% inhibition) agent against colon (ht-29), breast (sk-ov-3) and ovarian (mda-468) cell lines as compared to doxorubicin (80% inhibition). compound 15 did not show in vitro src kinase inhibitory activity (ic 50 < 300 mm) as compared to staurosporin (ic 50 = 0.6 mm) [34] . han and colleagues synthesized succinimide derivatives by c-h functionalization of chromone, naphthoquinone and xanthone scaffolds with maleimide scaffold. chromone derivatives (16a, b, c) showed only minute activity (ic 50 < 50 mm) versus mcf cell line [35] . el-garah, et al. synthesized chromone carboxamide derivatives. compound 17 presented prominent activity (ic 50 = 0.9 mm) against mcf-7 cancer cell line in comparison to tamoxifen (ic 50 = 0.39 ± 0.01 mm). structure activity relationship (sar) studies highlighted that attachment of fluorine atom at position # 6 of chromone core produced more active derivatives. replacement of fluorine atom by chloro and methyl groups produced less active derivatives. the presence of propyl side chain at the amide group also increased the activity. compound 18 also presented in-vitro anti-inflammatory activity (79.9 ± 6.6% inhibition) as lipoxygenase (lox) inhibitor. derivatives having hydrophilic group showed better anti-inflammatory activity [36] . ali, et al. synthesized chromone annulated phosphorous heterocycles as anticancer agents. phosphorous reagents used in the synthesis were phosphorous halides, phosphorous sulfides and phosphonic acid. anticancer activity was evaluated by using crystal violet blue assay. compounds 19 and 20 exhibited prominent activities against hepg-2 (ic 50 = 1.61 mg/ml, ic 50 = 2.49 mg/ml) and hct-116 (ic 50 = 1.72 mg/ml, ic 50 = 1.56 mg/ml) as compared to doxorubicin (hep-g-2 ic 50 = 0.467 mg/ml, hct-116 ic 50 = 0.468 mg/ml). the thiophosphoryl (p=s) bond was described as major cause of cytotoxicity of these compounds as compared to phosphoryl group (p=o) [37] . sun, et al. carried out synthesis of thiopyrano [4,3-d] pyrimidne derivatives having chromone molecules. compound 21 displayed significant inhibition of mtor (ic 50 = 1.10 ± 0.10 mm) and p13ka (ic 50 = 0.92 ± 0.12 mm) kinases. compound 21 (fig. 4 ) displayed marvelous in vitro activity against mcf-7 (ic 50 = 11.8 ± 6.9 mm), hela (ic 50 = 10.3 ± 0.58 mm) and hepg2 (ic 50 = 8.77 ± 0.83 mm) cancer cell lines as evaluated by mtt assay. docking investigation with mtor and p13ka kinases highlighted that morpholine, chromone and hydrazinyl groups are essential for antitumor activities. substitution on the chromone nucleus manifested significant influence on activity. introduction of carboxylic group on the chromone core proved more active as compared to methyl, ethyl and hydroxyl group [38] . abu-aisheh, et al. synthesized amidrazone derivatives having flavone scaffold. upon evaluation as anticancer agents by mtt assay, compounds 22 (ic 50 = 1.42 ± 0.13 mm) and 23 (ic 50 = 2.92 ± 0.94 mm) showed prominent in vitro activity versus breast cancer cell line (t47d) as compared to doxorubicin (ic 50 = 0.33 ± 0.05 mm). replacement of piperazine ring by piperidine produced less active agents against breast cancer. derivatives having phenyl group at position # 2 presented higher activity as compared to methyl group. these compounds can be good candidates as anticancer agents [39] . singh, et al. synthesized chromone and isoxazolidine based compounds by regioselective and stereoselective 1,3-dipolar cycloaddition reaction. compound 24 (ic 50 = 0.7 mm) exhibited prominent in vitro activity against a549 cell line in comparison to paclitaxel (ic 50 = 0.4 mm). this compound bears disubstituted isoxazolidine scaffold. this compound also induced apoptosis in hl-60 cancer cell line [40] . satyajit singh and co-workers synthesized chromano piperidine fused isoxazolidine molecules. derivatives having electron withdrawing groups at the chromone core presented superior activity. compounds having aromatic ring attached with isoxazolidine presented better activity. compound 25 showed prominent in vitro cytotoxicity against colo (ic 50 = 12.6 mm) as compared to fluorouracil (ic 50 = 21 mm). compound 25 also exhibited moderate activity against imr-32 (ic 50 = 55.2 mm) as compared to adriamycin (ic 50 = 1.7 mm). compound 26 (ic 50 = 10.7 mm) presented prominent activity against neuroblastoma (imr-32) cell line [41] . zwergel and co-workers synthesized chromone and coumarin based benzofuran derivatives. biological evaluation on human leukemia (k562) cell line was carried out. compounds 27 and 28 exhibited prominent activities having 72% and 63% cell survival respectively by using 50 mm concentrations. compound 27 showed 24% apoptosis. substitution on chromone nucleus does not have significant influence on activity. replacement of benzofuran by naphthofuranone produced more active compound towards apoptosis [42] . zhu, et al. designed and synthesized thienopyrimidine and chromone derived compounds as mtor/p13ka inhibitors [43] . compound 29 (97.2 ± 0.4% inhibition) presented prominent activity against mtor/p13ka kinase. derivative 29 also manifested notable in vitro activity versus h460 (ic 50 = 1.2 ± 0.3 mm) and pc-3 (ic 50 = 0.85 ± 0.04 mm) cell lines in comparison to positive control (ic 50 = 9.52 ± 0.29 mm, ic 50 = 16.27 ± 0.54 mm against h-460 and pc-3). chromone molecule having carboxylic acid or nitro group was found to be optimum for the activity in this series. docking studies revealed that chromone molecule is vital for activity. carboxylic group of chromone interacted via hydrogen bonding with trp-2239 and arg-2348. morpholine group formed hydrogen bonding with val-2240 [44] . diabetes mellitus is caused by the elevated level of glucose in the blood due to improper production of insulin. it is a very common problem all around the world [45] . currently available anti-diabetic drugs are linked with various side effects [46] . anti-diabetic properties of chromone derivatives are described in this section. ceylan-unlusoy, et al. attached chromone scaffold with 2,4-imidazolidindione and 2,4-thiazolidindione. attachment of heterocyclic rings at position # 3 produced more active derivatives as compared to position # 2. compounds 30 (142.7 ± 17.60%) and 31 (155.4 ± 35.16%) (fig. 5 ) showed prominent in vitro insulinotropic potential with dose of 1 mg/ml as compared to standard drug glibenclamide (138 ± 13.99%). incorporation of methyl and ethyl group in the heterocyclic ring showed comparable activity to unsubstituted derivatives [47] . later on, ceylan-unlusoy, et al. synthesized chromone derivatives having imidazolidindione, 2,4-thiazolidindione and 2-thioxoimidazolidine-4-one heterocyclic cores. derivatives having substituted 2,4-thiazolidinione ring demonstrated better activity and the most active agent carries methyl group at heterocyclic nitrogen. therefore lipophilic groups at the heterocyclic nitrogen were found significant for increasing the activity. compound 32 (dose = 0.001 mg/ml) was the most prominent which increased the release of insulin (120.6 ± 13.53%) as compared to glibenclamide (145.7 ± 7.74%) [48] . wang, et al. linked chromone to the benzene sulfonamide through hydrazone linkage to produce new a-glucosidase inhibitors. the a-glucosidase enzyme is involved in the hydrolysis of carbohydrates and releases glucose. compound 33 showed excellent in vitro inhibition (ic 50 = 20.1 ± 0.19 mm) of this enzyme in comparison to acarbose (ic 50 = 817.38 ± 6.27 mm). compound 33 carries a free sulfonamide group attached to the phenylhydrazone. replacement of phenylhydrazone by benzohydrazide and benzene ring by thiophine ring produced less active molecules. compound 33 displayed non-competitive inhibition as determined by lineweaver-burk plot. in molecular docking studies, hydrogen bonding was observed between the drug molecule and asp-214 and arg-439 of enzyme [49] . one year later, wang, et al. synthesized hybrid molecules comprising chromone-isatin as a-glucosidase inhibitors. these molecules exhibited excellent in vitro blockage of this enzyme and compound 34 (ic 50 = 3.18 ± 0.12 mm) appeared as the most potent in this series. substitution on the chromone core was very important where introduction of hydroxy group significantly enhances the activity. molecular docking studies also showed interaction (binding energy = -8.8 kcal/mole) of this compound with the glucosidase enzyme. 4-bromophenyl moiety showed hydrophobic interactions with phe-157 and phe-177, ala-278 and phe-300. benzopyrone formed ð-ð interaction with phe-300. hydroxyl group formed hydrogen bonding with gln-350 [50] . alpha-amylase is an enzyme involved in the hydrolysis of carbohydrates. salar, et al. connected chromone to hydrazinyl thiazole to produce the new hybrid molecules. upon in vitro evaluation as the a-amylase inhibitors, compound 35 showed prominent inhibition (ic 50 = 2.826 ± 0.06 mm) of this enzyme in comparison to acarbose (ic 50 = 1.9 ± 0.07 mm). compound 35 showed a docking score of -7.1717 and p-p interactions with trp-59 of a-amylase. compound 35 also exhibited dpph (2,2-diphenyl-1-picrylhydrazyl) (ic 50 = 1.13 ± 0.15 mm) and abts (2,2 / -azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ic 50 = 1.083 ± 0.15 mm) radical scavenging activities. compound 35 bears unsubstituted phenyl ring with thiazole. replacement of phenyl group with biphenyl core also produced more active compounds. incorporation of hydroxyl group at the aromatic ring decreased the activity. dichloro-substituted derivatives at the aromatic ring produced more active compounds as compared to mono-substituted compounds. attachment of methyl group with chromone core also produced less active derivatives [51] . parthiban, et al. synthesized quercetin based chromone derivatives as alpha-amylase inhibitors. various modifications in the chromone core of quercitin were carried out such as introduction of furan and indole ring. compounds 36 (ic 50 = 13 ± 0.16 mm) and 37 (ic 50 = 12 ± 0.14 mm) presented prominent in vitro activities as alpha amylase inhibitor as compared to quercitin (ic 50 = 22 ± 0.01 mm). in these derivatives chromone core is attached with indole ring. derivatives having aliphatic side chains at the indole nitrogen presented higher activity as compared to aromatic rings. molecular docking studies showed that chromone core forms hydrophobic interaction with trp58, tyr62 and leu165. diethylamino group of compound 37 interacted via hydrogen bonding as well as hydrophobic interaction with glu233 and ile235. these derivatives have the potential for further investigations as anti-diabetic agents [52] . parasites such as bacteria, viruses, fungi, protozoa, trypanosomes, etc. cause various diseases in human beings and are responsible for high mortality and morbidity [53] . ate activity (10 -12 mg/ml) against sensitive h37rv as compared to ethambutol (2 mg/ml) and streptomycin (2 mg/ml). it was assumed that these compounds act on the lipoprotein part of the cell wall of mycobacterium tuberculosis [62] . cano, et al. synthesized fluorine-containing chromone and tetrazole hybrid molecules by ugi-azide reaction [63] these derivatives displayed moderate antimicrobial activity as is evident by compound 51 (mic = 20 mg/ml) activity versus pseudomonas aeruginosa (p. aeruginosa) as compared to cefotaxime (mic = 0.5 mg/ml). compound 52 also displayed low antiamoebic activity (ic 50 = 61.7 mg/ml) as compared to metronidazole (ic 50 = 1.5 mg/ml). compound 53 exhibited antifungal activity against sporothrix schenckii (s. schenckii) at the concentration of 6.25 mg/ml. introduction of halogen atoms at the chromone core produced more active derivatives as compared to nonhalogenated derivatives [64] . reddy, et al. produced the fused hybrid molecules by reacting 2-amino chromone, benzaldehyde, 1,4-dimedone to produce chromeno-tetrahydroquinoline. antibacterial activity was tested against p. aeruginosa, s. aureus, e. coli and bacillus subtilis (b. subtilis). in these derivatives, tetrahydropyridine is embed-ded in dimedone and chromone scaffolds. agar well diffusion method was used for assessing antibacterial activity. compounds 54, 55 and 56 were most active derivatives (zoi = 22 -37 mm) as compared to streptomycin (zoi = 25 -40 mm) against these bacteria. derivatives bearing small alkyl chains demonstrated better activity. introduction of cyclic rings e.g. cyclopropyl, cyclobutyl and cyclopentyl at this position produced less active derivatives [65] . pouramiri, et al. showed excellent activity (100%) against meliodogyne incognita by using concentrations 10 mg/ml and 25 mg/ml. standard drug tioxazafen exhibited 100% inhibition at 25 mg/ml and 92.9% at 10 mg/ml. sar studies revealed that incorporation of methyl, ethyl and phenyl groups in the linker chain produced less active derivatives. attachment of trifluoromethyl group at position # 3 of pyrazole scaffold produced more active derivatives as compared to bromide, cyanide and methyl groups [68] . siddiqui, et al. synthesized prazolyl pyranopyridines derivatives by the reaction of 3-acetoacetyl benzopyranopyridone with different hydrazine derivatives. benzopyranopyridones contain condensed chromone ring and are the intermediate products in this series. among these derivatives, compound 65 (fig. 8 ) manifested prominent activity against salmonella typhi (s. typhi, zoi = 12 mm), salmonella dysenteriae (s. dysenteriae, zoi = 19 mm) and klebsiella pneumoniae (k. pneumoniae, zoi = 18 mm) as compared to chloramphenicol (zoi = 16 mm, 23 mm, 23 mm against these bacteria) [69] . batula, et al. synthesized aryl isoxazole and 6-fluorochromone carboxylate derivatives in which both these scaffolds were linked by ester linkage. the introduction of aryl groups at the isoxazole core enhanced the antibacterial activity. compound 68 showed activity against a. niger (mic = 18.75 mg/ml) and c. albicans (mic = 18.75 mg/ml) as compared to amphotericin b (mic = 1.562, 6.25 mg/ml respectively against these microbes). introduction of halogen-substituted phenyl rings significantly increased antifungal activity. compounds 66 and 67 were most active against b. subtilis having mic value of 9.375 mg/ml for each compound as compared to streptomycin (mic = 6.25 mg/ml) [70] . hessein and co-workers synthesized furochromone, furocoumarin and benzofuran derivatives having sulfonamide group. upon in vitro evaluation, compound 69 exhibited antimicrobial potential against e. coli (zoi = 20 mm) and aspergillus ochraceus (zoi = 19 mm). compound 70 (zoi = 19 mm) was most prominent against e.coli as compared to chloramphenicol (zoi = 38 mm). attachment of aminophenyl and biphenyl ring to the sulfonamide group significantly improved the antibacterial activity. addition of benzotriazole or biphenyl acetamide group did not improve the antimicrobial activity [71] . aggarwal, et al. synthesized 1,2,4-dithiazolyl derivatives as antimicrobial agents. compound 71 showed prominent activity against b. subtilis (mic = 0.78 mg/ml), s. cerevisiae (mic = 6.25 mg/ml) and c. albicans (mic = 3.12 mg/ml) as compared to fluconazole (mic = 1.9 mg/ml, 3.9 mg/ml versus s. cerevisiae, c. albicans). compound 72 presented excellent activity against e. coli (mic = 1.56 mg/ml) and b. subtilis (mic = 1.56 mg/ml) as compared to gentamicin (mic = 0.9 mg/ml and 0.75 mg/ml against e. coli and b. subtilis). sar investigation declared that substitution of the phenyl ring at 1,2,4-dithiazolyl ring is very important for antimicrobial activity and addition of the halogen atom at para-position significantly improves the activity. addition of electron-withdrawing group e.g. chlorine and bromine at position # 6 and # 7 of chromone scaffold also enhances activity while attachment of electron-donating group e.g. methyl lowers the activity [72] . gadhave, et al. synthesized fluorine containing pyrazolone derivatives having chromone molecule by a knoevenagel condensation reaction [73] . compound 75 (fig. 9) showed prominent activity against streptococcus pyogenes (mic = 62.5 mg/ml) in comparison to ampicillin (mic = 100 mg/ml). compounds 76 was most active against s. aureus having mic value of 62.5 mg/ml. compound 77 was most active against p. aeruginosa (mic = 62.5 mg/ml) in comparison to ampicillin (mic = 250 mg/ml). it was found that addition of propyl and trifluoromethyl group at the pyrazole ring produced potent derivatives against gram-positive bacteria [74] . knoevenagel-cope condensation reaction was also used by bari, et al . different concentrations were used for testing antibacterial activity and no direct relationship was observed between concentration and antibacterial activity [77] . badhade, et al. synthesized chromone and isoxazole conjugates without any linker group. upon in vitro evaluation as antibacterial agents, these derivatives exhibited excellent activity. compounds 82 and 83 (fig. 9 ) exhibited notable activities against b. subtilis and s. aureus presenting mic values of 10 mg/ml equivalent to standard drug. incorporation of halogen and alkyl groups in the chromone ring produced more active compounds [78] . chromone scaffold was attached with 1,2,3-triazole by dofe and co-workers to produce new derivatives. compounds 84 and 85 exhibited prominent antifungal activities (mic = 12.5 mg/ml) against c. albicans for both compounds as compared to miconazole (mic = 12.5 mg/ml). derivatives 84 and 85 showed prominent antibacterial activity (mic = 25 mg/ml) against b. noor ul amin mohsin et al. the process of inflammation is related to various diseases. nonsteroidal anti-inflammatory agents are frequently used as remedy of inflammation but are associated with the major adverse effect of gastrointestinal ulceration [82] . therefore the development of new anti-inflammatory drugs having good safety profiles is necessary. chromone derivatives have also presented anti-inflammatory activities. tnfa (87% inhibition) as compared to standard drug dexamethasone (71 and 84% inhibition of tnfa and il-6 respectively). in compound 97, piperazine and chromone scaffolds are separated by methylene group and piperazine is further attached to a pyrimidine. replacement of pyrimidine ring by pyridine, p-methoxyphenyl ring produced equipotent derivatives. substitution of pyrimidine ring by methyl, ethyl and acetyl groups produced less active derivatives [85] . alzheimer's disease (ad) is a neurological ailment mostly among the elder people and is indicated by memory loss and dementia [86] . chromone core has been attached with various other pharmacophores to produce new multifunctional agents. natural compounds have potential to inhibit some toxicities of alzheimer disease [87] . liu, et al. attached chromone-2-carboxamide with alkylbenzylamines as anti-alzheimer agents. compound 98 (fig. 11 ) displayed excellent in vitro acetylcholinesterase (ache) inhibition (ic 50 molecular modeling investigation of this derivative also showed interaction with the active site of ache. the presence of amino group at position # 2 of chromone ring forms additional hydrogen bonding with tyr-510 and gly-523 of ache. benzene ring of chroman fragment showed p-cation interaction with arg-522. the increased activity was also linked to the extra amino functionality in the chromone ring [18] . hybrid molecules of 4-oxo-4h-chromene and tacrine were synthesized by fernandez-bachiller and colleagues in which cholinesterase inhibitory property of tacrine and antioxidant property of chromone were combined. alkylene diamine was used as linker between these two pharmacophores and a chain of ten carbon atoms was found optimal for best activity. hybrid proved more potent than parent drug tacrine but showed inhibition of ache and buche enzymes. 2-amino-4-methyl phenol group occupied the hydrophobic pocket formed by leu-171, ile-198 and ile-199 [90] . mackhaeva, et al. synthesized 2-vinyl chromone derivatives as selective butyryl cholinesterase (buche) inhibitors. derivatives having n-benzyl and n-vinyl methoxy carbonyl substituted compounds presented more selectivity for buche. in this series, compound 104 appeared as the most potent inhibitor (ic 50 = 2.27 ± 0.18 mm) of buche in comparison to tacrine (ic 50 = 0.0290 ± 0.0002 mm). compound 104 carry bromine atom at position # 6 of chromone core. introduction of ethoxy group at position # 8 of chromone core produced less active derivatives. molecular docking studies showed that methoxy carbonyl group interacted with anionic site formed by gly116, gly117 and ala199. the n-benzyl group interacted with tyr440 and trp430 and showed more affinity (binding free energy = 1.5 kcal/mol) as compared to n-methyl substituent at this position [91] . cagide and co-workers synthesized chromone-2-phenyl carboxamide derived compounds as adenosine a1 (ha1) receptor ligands. different substituents were attached at the exocyclic phenyl ring. compound 105 presented prominent activity at ha1 (ki=0.219 mm) receptor and this compound also exhibited selectivity for this receptor as compared to ha3. it bears nitro group at ortho position of phenyl ring. shifting of nitro group at meta or para position produced less active derivatives. authors explained that receptor sites of ha1 (lined by asn170, glu170, glu172 and thr270) and ha3 (ser73, gln167, val169, leu264) are different from each other. these derivatives also follow lipinski rule of five and possess drug like properties [92] . ali abid, et al. synthesized sulfonyl hydrazone derivatives of 3-formyl chromones as monoamino oxidase (mao) inhibitors. these compounds showed capacity to inhibit mao-a and mao-b enzymes simultaneously. compound 106 was the most active (ic 50 = 0.33 ± 0.01 mm) in vitro mao-a inhibitor in comparison to clorgyline (ic 50 = 0.004 ± 0.0003 mm). it bears chlorine atom at position # 6 of chromone skeleton. replacement of chlorine by methyl group produced less active derivatives. compound 107 was the most active (ic 50 = 1.12 ± 0.02 mm) mao-b inhibitor as compared to deprenyl (ic 50 = 0.0196 ± 0.001 mm). it carries fluorine atom at position # 6 and replacement of fluorine atom by chlorine or bromine atom produced less active derivatives. molecular docking studies of compound 107 with mao-b showed that sulfonamide oxygen interacted by hydrogen bonding with tyr60. oxygen atoms of chromone ring and carbonyl group interacted through hydrogen bonding with gln206 and tyr435. derivatives in this series exhibited good pharmacokinetic properties such as oral bioavailability [93] . reactive oxygen species produce oxidative damage to various biomolecules. naturally occurring compounds have also displayed antioxidant activities [94] . chromone derivatives also play significant role as antioxidants and free radical scavengers [95] . berczynski, et al. (2013) evaluated chromone conjugated derivatives of 2,4-thiazolidinedione, 2,4-imidazolidinedione, 2-thioxo-imidazolidine-4-one as antioxidant agents. derivatives having 2-thioxo-imidazolidine scaffold exhibited prominent activity against oh·, dpph· free radicals. compound 108 (fig. 12 ) appeared as the most active in vitro free radical scavenger (ic 50 = 0.353 ± 0.04 mmol/l) in comparison to standard drug tiron (ic 50 = 0.451 ± 0.065 mmol/l). in compound 108, 2, 3-double of chromone is in conjugation with the 4-carbonyl group and this is the reason for increased antioxidant activity [96] . berczynskai, et al. (2013) evaluated chromone molecules having 2,4-thiazolidinedione and 2,4-imidazolidinedione heterocyclic rings for antioxidant activities. heterocyclic rings were further attached with substituted aromatic rings. in dpph (1,1-diphenyl-2-picryl-hydrazyl) radical scavenging assay, compounds 109 (ic 50 = 194 ± 3.5 mmol/l) and 110 (ic 50 = 364 ± 3.3 mmol/l) presented prominent activity as compared to vitamin c (ic 50 = 346 ± 28 mmol/l). by using the dmpo-oh (5,5-dimethyl-1-pyrroline-1-oxide) spin adduct method, 109 (41.7% inhibition) and 110 (35.1% inhibition) also exhibited free radical scavenging activity [97] . takao and colleagues synthesized 3-styryl chromone derivatives by konevenagel reaction as a-glucosidase inhibitor and as antioxidant agents. compounds 111 (ec 50 = 17 mm) and 112 (ec 50 = 23 mm) showed prominent in vitro activities as dpph scavenger as compared to ascorbic acid (ec 50 = 23 mm). compounds 111 (ic 50 = 16 mm) and 112 (ic 50 = 10 mm) also exhibited inhibition of a-glucosidase enzyme. both compounds contain catechol ring attached to the chromone scaffold. sar studies showed that incorporation of methyl group and halogen atoms on the ring b did not increase the activity but the incorporation of hydroxyl group produced active molecules. dihydroxy derivatives showed better activity as compared to monohydoxy derivatives. [98] . proenca, et al. attached chromone with 3,4-dihydroxy phenyl core via 1,3-diene system. compound 113 (ic 50 = 125 ± 13 mm) and 114 (ic 50 = 121 ± 9 mm) showed prominent activity as scavenger of hydrogen peroxide (h 2 o 2 ) as compared to standard drug quercetin (ic 50 = 1338 ± 42 mm). compound 114 also exhibited effective scavenging of hocl (ic 50 = 17 ± 3 mm), roo· and onoo -·(ic 50 = 0.29 ± 0.02 mm). incorporation of hydroxyl groups both at position # 5 and # 7 of chromone scaffold was important for the antioxidant activity. no prominent difference in the activity was observed for these hydroxyl groups [99] . soengas, et al. synthesized chromone-3-pyrazoly derivatives as free radical scavenger and alpha glucosidase inhibitor. compound 115 appeared as the most effective antioxidant agent (ic 50 = 23 mm) as compared to standard drug a-tocopherol (ic 50 = 23 mm). it possesses catechol group in its structure and it proved more active as compared to monohydroxyl derivatives. addition of hydroxyl group in the chromone ring had no significant influence on the activity [100] . rao, et al. synthesized styryl chromone derivatives in which styryl group was attached at position # 2 of chromone core. antioxidant activity was monitored as scavenger of superoxide free radical. antioxidant activity was dependent on the number of hydroxyl groups, and compound 116 emerged as the most active agent (ic 50 = 234 mm) in comparison to vitamin c (ic 50 = 852 mm). compound 116 also showed excellent antibacterial activity against xanthomonas campestris (zoi = 11.3 mm) and agarobacterium tumafaceins (zoi = 11 mm) as compared to streptomycin (zoi = 12 -15 mm). chromone derivatives having hydroxyl group also presented better antimicrobial activity. replacement of hydroxyl group with methoxy group decreased antibacterial activity and increased antifungal activity [101] . demetgül and co-workers linked chromone with chitosan to produce the chromone-chitosan schiff base. upon in vitro evaluation as antioxidant agent by dpph radical scavenging assay, compound 117 emerged as the most potent (ic 50 = 0.88 mg/ml) antioxidant agent as compared to chitosan alone. the increased antioxidant activity was related to the phenolic group present in chromone [102] . thus, chromone is a promising scaffold for the synthesis of new therapeutic agents, and hybrid molecules presented in this review can be used as lead for future drug discovery. actions of flavonoids and coumarins on lipoxygenase and cyclooxygenase el-edfawy, phosphorus, sulfur alzheimer's dis key: cord-000884-zq8kqf6h authors: shen, hsin-hui; lithgow, trevor; martin, lisandra l. title: reconstitution of membrane proteins into model membranes: seeking better ways to retain protein activities date: 2013-01-14 journal: int j mol sci doi: 10.3390/ijms14011589 sha: doc_id: 884 cord_uid: zq8kqf6h the function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. the activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. the reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. however, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. this review will discuss the reconstitution of membrane protein activities in four different types of model membrane—monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. variation in the surrounding model environments for these four different types of membrane layer can affect the three-dimensional structure of reconstituted proteins and may possibly lead to loss of the proteins activity. we also discuss examples where the same membrane proteins have been successfully reconstituted into two or more model membrane systems with comparison of the observed activity in each system. understanding of the behavioral changes for proteins in model membrane systems after membrane reconstitution is often a prerequisite to protein research. it is essential to find better solutions for retaining membrane protein activities for measurement and characterization in vitro. the cell membrane separates intracellular components from the outside environment and is constituted by various phospholipids, cholesterol, glycolipids and proteins. integral membrane proteins have at least one polypeptide segment spanning the membrane bilayer whereas peripheral membrane proteins are temporarily attached to the lipid bilayer or to integral membrane proteins by various interactions such as hydrophobic, electrostatic and other types of non-covalent interactions. membrane proteins work as a selective filter to regulate molecules entering cells and also serve in communicating with the surrounding environment. thus, membrane proteins play an essential role in the physiological functions needed for cell survival. the functional activities of membrane proteins are modulated by the structure of the surrounding lipids molecules in the membrane [1, 2] ; thus the composition of the lipid bilayer can affect the inter-or intra-molecular interactions between the lipid bilayer and membrane proteins [3] . investigating membrane proteins in vivo is difficult because the membrane proteins are associated with a complex mixture of other proteins, and are prone to aggregation in solution [4] . it is still a major challenge at this stage to extract information needed in vivo to address specific questions in the function of the cell membrane. to simplify cell membrane systems, model membranes such as monolayers, bilayers, liposomes and nanodiscs have been developed, enabling detailed investigation of membrane protein structure in lipid membranes. model membrane environments more closely resemble the natural lipid bilayer than alternatives such as detergents. however, many features of phospholipid structure need to be considered and optimized in the creation of a suitable model membrane. for example, the hydrophobicity of the lipid chain defined by the lengths of the fatty acid chains, is an important parameter for retaining protein activity. other factors affecting the reconstituted membrane protein activity are the chemical properties of the lipid head groups which control membrane hydrophilicity. both parameters are crucial in stabilizing membrane protein structure. there are a number of approaches used to create a model membrane in order to mimic properties of the native cell membrane, and we will review these various approaches for reconstituting membrane proteins into different types of model membrane-monolayers [5] , supported planar lipid bilayer [6] and liposomes [7] as shown in figure 1a -c. we will also discuss the emerging technology of nanodiscs [8] ( figure 1d ). nanodiscs are a new class of model membrane, with attractive properties that address shortcomings of other approaches in the study of membrane proteins. the first section gives a brief summary of each method and a comparison of their strengths and weaknesses. in the following section, we describe four case studies and will compare the protein activity changes when the membrane proteins are reconstituted into different model membranes. in these case studies, we demonstrate how protein activities are modulated by the lipid environment and discuss how this environment helps to retain protein activities. and black in b represent water and a substrate respectively. nanodiscs contain membrane scaffold proteins, shown in green. one of the most common approaches to study the membrane protein structure and activity uses a langmuir monolayer at the air-water interface. this method has been extensively used for more than a century [9, 10] . reconstitution of membrane proteins helps obtain further information on their organization and structure in the langmuir membrane [11, 12] . it is a simple method to create a phospholipid monolayer at an air-water interface. basically, a desired amount of lipid or lipid mixtures are dissolved in organic solvents such as chloroform or chloroform/ethanol mixtures, followed by spreading the lipid/solvent mixtures on the water surface. by evaporating out the solvent, the phospholipid molecules self-assemble vertically as a monolayer film at the air-water interface, with their hydrophilic head groups immersed in the water and their hydrophobic tail pointed to the air as shown in figure 1a [13] . a major advantage of using the langmuir monolayer system is that parameters such as thickness, surface pressure, molecular area and subphase thickness can be well controlled [10] . more advanced characterization techniques, such as π-a isotherm uv-vis adsorption, x-ray reflectivity, ellipsometry and rheology, have been developed to gain detailed information on the binding of proteins onto the phospholipid monolayer and to monitor enzyme activities when binding to the monolayer [14] . however, a limitation of langmuir monolayers is that the lack of a layer comparing to the natural cell structure (bilayer) and the high surface tension of water that can cause protein denaturation. despite this limitation, there are several successful studies using this approach. two types of membrane proteins in monolayer model membrane system will be briefly described below: rhodopsin [15, 16] , bacteriorhodopsin [17, 18] and the aliphatic peptide gramicidin [19, 20] have been successfully reconstituted and studied in monolayers at the air-water interface. in order to obtain information on the secondary structure and orientation, the protein layer can be investigated in situ at the air-water interface by either polarization modulation infrared reflection absorption spectroscopy (pm-irras) or x-ray reflectivity in combination with surface pressure-area isotherms [21] . the study of gramicidin is an example of such an approach, and while gramicidin is unfolded at high molecular area (low pressure), it is refolded upon compression and retains its precise structure and orientation. likewise, for both rhodopsin and bacteriorhodopsin, the secondary structures measured in monolayers are indistinguishable from that in native membranes when appropriate conditions are used. while some experiments have suggested that spreading of rhodopsin in certain conditions (>5 m/n) leads to denaturation [21] , bacteriorhodopsin, in contrast, is very stable in most testing conditions (compression and temperature change). the different properties of the protein are probably due to the ability of baceriorhodopsin to form a stable two-dimensional crystalline structure at the air-water interface [21] . phospholipid monolayers are simple model membrane systems that are perfectly suited to study the binding of peripheral proteins onto a membrane surface. peripheral membrane proteins spontaneously bind onto phospholipid monolayers at the air-water interface by injecting themselves into the subphase underneath the lipid monolayer. in most cases, useful information can be obtained by measuring the binding of peripheral proteins onto the monolayer. for example, the kinetics and dynamics of adsorption of myristoylated and nonmyristoylated recoverin onto phospholipid monolayers have been investigated using surface pressure isotherm described in figure 2 [21] . the curve can be fitted with stretched exponential which can convert into the rate of adsorption of myristoylated and nonmyristoylated which is 0.028 s −1 and 0.0048 s −1 , respectively. this indicates that the adsorption of myristoylated recoverin is six times faster than nonmyristoylated recoverin. reconstituting enzymes into the langmuir monolayers at the air-water interface has been found to be a very useful approach to understand the hydrolysis of membrane phospholipids. for example, the interfacial recognition and adsorption of phospholipases a2 (pla2) and phospholipases c (plc) to the phospholipid membrane interface are poorly understood. by using this approach, it appears that both pla2 and plc are active at the monolayer model membrane, indicating that the kinetics of phospholipid hydrolysis at the air-water interface can be monitored by biophysical characterization techniques in situ such as pm-irras and infrared reflection adsorption spectroscopy [22] . moreover, it has been found that in the presence of calcium, phospholipid hydrolysis by pla2 resulted in the production of calcium-palmitate complexes. this suggests that calcium is necessary for pla2 secretion. the formation of a supported lipid bilayer on a solid substrate was reported by tamm and mcconnell in 1985 as a new model membrane system to study the physical properties of biological membranes and their constituent lipid and protein molecules [23, 24] . supported planar lipid bilayers are prepared by several methods [25, 26] . vesicle fusion is the simplest method for supported bilayer formation and the fusion mechanism on a hydrophilic support is well understood [27, 28] . essentially, the bilayer is prepared by the fusion of small unilamellar vesicles on solid supports such as sio 2 , glass and modified gold surface by van der waals, electrostatic, hydration and steric forces. the supported lipid bilayer has polar hydrophilic headgroups facing the aqueous surroundings and two hydrophobic tails that face the interior of the membrane which more closely resembles biological membranes than the langmuir monolayer. the supported lipid bilayer can confer many key functions to biological membranes. however, one side of the hydrophilic head group is still tightly attached to the solid support and this may, in some cases, affect the fluidity of the model membrane. this matters, since integral membrane proteins may not diffuse in the plane of the membrane. furthermore the orientation of membrane proteins cannot be controlled in the supported planer lipid bilayer. to alleviate some of these problems, a new tethered polymer-supported planar lipid bilayer system was developed to investigate the reconstitution of integral membrane proteins in a laterally mobile form into the supported lipid bilayer [29] . wagner and tamm [30] have successfully designed a supported lipid bilayer on a polyethyleneglycol cushion shown in figure 3 . the polymer cushion minimizes the interactions of the proteins with the substrate and the polymer. it also provides a soft support and, for increased stability, covalent linkage of the membranes to the supporting quartz or glass substrates. in low polyethyleneglycol concentration regimes, the bilayers were assembled with high lateral lipid diffusion coefficients (0.8-1.2 × 10 −8 cm 2 /s). cytochrome b5 and annexin v were used to test the polyethyleneglycol cushion system. two populations of laterally mobile proteins were observed in the polyethyleneglycol cushion-supported bilayers. approximately a quarter of cytochrome b5 diffused with a diffusion coefficient of 0.8-1.2 × 10 −8 cm 2 /s, and more than half of the cytochrome b5 diffused with a diffusion coefficient of ~2 × 10 −10 cm 2 /s. similar results were found in the annexin v system. annexin v diffused with two populations with diffusion coefficients of 3 × 10 −9 cm 2 /s and 4 × 10 −10 cm 2 /s. the new polymer-supported lipid bilayer system has increased the mobile fraction and retained the full lateral mobility of both cytochromes b5 and annexin when integrated or bound to the supported lipid. although polymer cushions allow for successful integration of small membrane proteins into bilayers, further challenges stem from studies with large transmembrane proteins. polymer cushions cannot provide large transmembrane proteins with good solvent accessibility, or enough space for the motion; required for the activity. while several types of polymer cushions have been developed, including polymethyl methacrylate diblock polymer cushions [31] , poly(ethylene imine) [32, 33] cushions and poly(ethylene glycol) tethered lipopolymers [30] , these cushions are mostly limited to a thickness of up to 10 nm. a recent development of a maleic anhydride copolymer thin film has film thickness up to 60 nm [34] . the hydrophilic polymer-cushioned supported lipid bilayers provide a higher mobility and homogeneous distribution of the incorporated beta-amyloid precursor protein cleaving enzyme (bace) on the bilayer surface, and enhances the enzymatic activity of bace (increased from 8% to 16%). even so, the activity of the incorporated bace remains significantly lower (16%) than that of the native enzyme (100%). another important classic category of membrane proteins are the transporters of ions and small molecules. studies of how ion channels regulate the transport of substrates [7] are important for fundamental biology. however, it is challenging to incorporate ion channels in supported lipid bilayers due to leakage or instability issues. detailed studies of ion channel conduction or gating require considerable period of time (possibly >1 h), and it is difficult to set up a stable and electrically quiet environment for the ion channel in planar lipid bilayer. a better alternative has proven to be reconstitution of ion channels into proteoliposomes. lipid vesicles, also known as liposomes, consist of a self-closed lipid bilayer. they have been widely used for more than 30 years to reconstitute the membrane proteins in unilamellar phospholipid vesicles. liposomes are relatively easy to construct by procedures such as extrusion method or ultrasonication, with reverse-phase evaporation. furthermore, giant vesicles of unilamellar or multilamellar nature can be "micro-manipulated" under an optical microscope. reconstitution of membrane proteins in liposomes usually requires detergents wherein purified membrane proteins are solubilized in detergent, then mixed with the desired phospholipid vesicles forming an isotropic solution of mixed phospholipid-protein-detergent micelles. the detergent can then be removed slowly by dialysis, gel filtration or biobead adsorption. when the detergent concentration reaches a critical level, the protein will spontaneously associate with the phospholipid membrane to form biologically active liposomes, called proteoliposomes. however, it has been a hard feat to control the final orientation of protein in the proteoliposomes [35] , as well as the amount of protein inserted due to the limited area available. in many cases, disorientation of the protein causes aggregation. despite these difficulties, there have been many successful cases of membrane proteins reconstituted in the proteoliposomes, and we describe two examples below. several integral membrane proteins have been successfully reconstituted into proteoliposomes such as rhodopsin [36] , g proteins [37, 38] , proapoptotic bcl-2 proteins and t-bid [39] , phosphocholine cytidylyltransferase (ct) [40] and p protein kinase c (pkc) [41] . however, these studies also found that the resulting protein activities are sensitive to the membrane curvature of the liposomes. this indicates that different phospholipids can cause considerable curvature stress changes in the liposomes [42] . specifically, the curvature stress has been suggested to modulate the free energy and folding of the integral membrane proteins [43] . sometimes the activity of different enzymes is modulated by the same driving force of the membrane curvature, but there may also be variation of activity through different mechanisms. for example, the activities of both ct [40] and pkc [41] are enhanced by increasing the negative curvature strain of the membrane. the activity of ct appears to be directly coupled with the membrane curvature, in contrast, the activity of pkc does not have a direct relationship with the curvature strain and enzymatic activity [41] . the activity of pkc is instead modulated by nonlamellar-forming lipids via a less direct mechanism. liposomes have been commonly used for reconstituting different types of transporters to allow for the free diffusion of solution or catalysis of obligatory co-transporters. a large number of functional membrane proteins have been successfully reconstituted into liposomes but only a few examples will be discussed here. the reconstitution of colicin ia and e1 in either soybean phospholipids or e. coli phospholipids show that there is channel formation in the liposomes but there are unspecific channels allowing passage of ions, such as rubidium, sodium, chlorine, potassium or phosphate but not of sugars [7, 44] . an example of the reconstitution of selective transport comes from the d-glucose transporter, purified from human erythrocytes and extracted from detergents followed by incorporation into proteoliposomes. with incorporation of the d-glucose transporter, the proteoliposomes become permeable to d-glucose but not to l-glucose. the transport was inhibited by cytochalasin b which is a potent inhibitor of d-glucose transporter [45, 46] . several types of atp-dependent ion transporters such as ca 2+ /mg 2+ -atpase, na + /k + -atpase, and h + /k + -atpase have been reconstituted into proteoliposomes [47] . upon addition of atp, ions are observed to be transported inwards and can form a complex. the single-channel property of channels incorporated into proteoliposomes can be investigated using the well-known patch-clamp method [48] . channel activity is monitored following excision of the patch from the proteoliposomes. ion-channel reconstitution makes possible the investigation of the influence of membrane lipid composition on channel function. the kinetic investigation of these channels under physiological conditions has been discussed elsewhere [47] . another up-to-date method is using organic solvent or oil mixed with water that creates water-in-oil (w/o) microdroplets coated by phospholipid. the hydrophilic head group immerses in the water and the hydrophobic tail locates in the oil/organic solvent phase. the application of the water-in-oil system could cover a wide range of applications from monolayer, planer lipid bilayer and liposomes. funakoshi et al. [49] and maglia et al. [50] used a planer lipid bilayer formed by two microdroplets driven to come in contact to reconstitute ion channels in the bilayer. this method is extremely simple and reproducible. recently, the water-in-oil microdroplets are extended to form liposomes by using droplet-transfer method invented by yoshikawa [51] . by using this approach, it is possible to modulate the lipid compositions of outer and inner leaflets and furthermore to orient a reconstituted membrane protein in liposomes [52] . nanodiscs offer a solution to some of the challenges described in the previous sections. the first attempt to reconstitute membrane proteins in the phospholipid bilayers using nanodisc technology was initiated by sligar's group a decade ago [8] . the nanodisc is a self-assembly of phospholipids and a membrane scaffold protein derived from human serum apolipoprotein a1. the detergent, cholate, can be used to solubilize phospholipids and membrane scaffold proteins into a micelle mixture. following detergent removal with dialysis or bio-beads adsorbent, a nanodisc self-assembles. the phospholipid associates as a bilayer domain while the membrane scaffold protein wraps around the edges of the discoidal structure in a belt-like configuration ( figure 1d ). it is possible to modify the diameter of the bilayer disc by genetically engineering the apolipoprotein a1 by changing the number of amphipathic helices. by this approach, the diameter of nanodiscs can be made anywhere from 9.8 to 17 nm, and therefore accommodate a range of membrane proteins. the ratio of phospholipid: membrane scaffold protein is precisely defined which helps engineer the different size of membrane proteins in the nanodiscs. detailed formation of different types of nanodiscs has been described elsewhere [53, 54] . the great advantage of using nanodiscs is keeping the membrane proteins in aqueous solution, in native-like phospholipid bilayer environment that is soluble, stable, monodisperse and detergent-free. most important, it isolates proteins or complexes as individual particles in monomeric or oligomeric states for analysis by techniques that range from activity assays to electron microscopy. since 2003, there have been more than 100 membrane proteins reconstituted into nanodiscs [54] , ranging from signaling receptors to transport machines. we will discuss the applications separately below. nanodiscs have been used to analyze the influence of binding substrate on monodisperse receptors which are isolated from the cell-surface membrane. those receptors include g protein-coupled receptors (gpcr) [55, 56] , cholera toxin receptor ganglioside g m1 , bacterial chemoreceptor [57] and epidermal growth factor receptor. introduced into nanodiscs, the receptors stay in monodispersed, controllable, predefined oligomeric states in which it is possible to characterize the oligomeric status. for example, two different gpcr proteins, the beta-adrenergic receptor (β 2 ar) and rhodopsin [58] have been extensively studied using nanodiscs. β 2 ar was one of the first receptors assembled into nanodiscs which was found to be functionally active (54% of starting activity recovered) and shown coupling to its g-protein. rhodopsin is a light-activated gpcr present in the photoreceptor cells of the retina and transducin is an important g-protein naturally expressed in retina rods and cones. assembly of functional rhodopsin into nanodiscs was found to activate transducin with high efficiency and to isolate the high affinity of transducin-metharhodopsin ii complex. this provides strong evidence that the monomeric state of rhodopsin can activate and interact with the transducin. a dimeric rhodopsin nanodisc was separated for monomeric forms using sucrose density gradients. even with two rhodopsins in the nanodiscs, interaction with a single transducin molecule was observed and found to activate the transductin with high efficiency [56] . numerous membrane associated enzymes have been incorporated into nanodiscs. cytochrome p450 (cyp) enzymes have been extensively studied, including cyp2b4 [59] , cyp6b1 [8] , cyp73a5 [60] and cyp19 [61, 62] . this system has provided a means for studying the extensive collection of membrane bound cytochromes p450 with the same biochemical and biophysical tools that have been previously limited to use with the soluble p450s. for example, the cytochrome p450 3a4 (cyp3a4) is a membrane-bound protein which is a human hepatic drug-metabolizing enzyme. most studies of the ligand binding by cyp34a are carried out in the presence of detergents below their critical micelle concentrations [63, 64] but are compared by the propensity of cyp34a to aggregate. even in studies attempting to use liposomes, cyp3a4 is unlikely to exist in its native state because the detergent concentrations are much higher than the phospholipid concentrations. as a result, the understanding of the structure and composition of cyp3a4 in the lipid phase was limited and the membrane effect on cyp3a4 ligand binding behavior is unclear. nanodiscs have been utilized to study cyp3a4 which displays monophasic reduction kinetics. with a high lipid-protein ratio, cyp3a4 is captured as a monomer. however, at lower lipid ratio, cy3a4 self-associates and heterogeneous behaviors are induced. the nanodiscs prohibit self-association in this case as there is only one cyp3a4 per nanodisc and show significant improvement in homogeneity and stability. this opens up new possibilities for detailed analysis of equilibrium and steady-state kinetic characteristics of catalytic mechanisms of cyp enzymes [63] . the sec translocon is a membrane-embedded protein assembly that drives protein translocation into or across membranes. the core translocon is formed from a trimeric arrangement of secy, sece and secg [65] . the secyeg promoter has 15 transmembrane helices sitting in the phospholipid membrane. the oligomerization of secyeg has been proposed to be necessary to proper function. researchers were successful in reconstituting sec into membrane vesicles in 1990 and have had great success in characterizing several partial reactions of secyeg functions [65] . reconstituting a single secyeg into a nanodisc with different types of lipids [66] suggests that the acidic lipids can stabilize the secyeg channel in the nanodisc bilayer and trigger dissociation of the seca dimer. a model has been proposed by alami et al. [66] , suggesting that the dissociation of the seca dimer provoked by the secyeg complex is followed by activation of the seca atpase. furthermore, dalal et al. [67] , using the nanodisc technology, have also shown that only the secy dimer together with acidic lipids supports the activation of the seca translocation atpase. recently, a high resolution single-particle cryo-em structure of single secyeg complexes in nanodiscs, bound to translating ribosomes was first solved at subnanometer resolution [68] . it allows the secyeg complex to be investigated in a natural lipid bilayer environment and identifies the ribosome-lipid interactions. wu et al. [69] also used surface plasmon resonance to investigate the competitive binding of ribosomes and seca. the data suggest that both ribosomes and seca can interact simultaneously with secyeg complex during membrane protein insertion, but seca competes with ribosome when it binds to the secyeg complex. in the previous section, we have shown that membrane proteins can be assembled into four different types of model membrane and the activities of some of the membrane proteins can be retained, allowing their physicochemical properties to be studied. but is there a model membrane system that is the best for membrane-protein reconstitution? the reconstitution of the same membrane protein into different model membranes has been compared and, in this section, we list four membrane proteins with varying activities in different model membranes. ganglioside g m1 is a naturally occurring native receptor that binds to cholera toxin via hydrogen bonds [70] . it is an excellent receptor for studying lipid-receptor interaction. several different approaches to reconstituting the glycolipid receptor g m1 in model membranes have enabled the measurement of binding of its interaction partner cholera toxin. in liposomes and supported lipid bilayer systems, the ganglioside g m1 is free to diffuse across long distances and exhibits a non-uniform lateral distribution, i.e., self-aggregation, even at low incorporation ratios. therefore the binding activity of ganglioside g m1 with cholera toxin b is restricted [71] . investigations of ganglioside g m1 incorporated into nanodiscs found reduced protein aggregation. bricarello et al. [72] found that the reconstitution of a low concentration of ganglioside g m1 in nanodiscs, shows binding of cholera toxin with a significantly higher affinity than in liposomes or supported lipid bilayers. this is due to the interaction of ganglioside g m1 with the headgroup region of the disc which reduces the oligomerization, thereby causing a potential effect on the affinity of toxin binding. thus, nanodisc technology restricts the ganglioside g m1 oligomerization by controlling the number of ganglioside g m1 monomer isolated by each nanodisc. borch et al. [73] have also used sensor chip-based surface plasmon resonance (spr) technology to measure the detailed kinetic binding of the interaction between soluble molecules and membrane receptors inserted in the bilayer of nanodiscs. the corresponding spr sensorgrams are displayed in figure 4 . overall, the change of the sensorgram indicates that the spr sensorchip is immobilized with histidine-modified nanodisc or the cholera toxin b bound to the nanodiscs. the sensorgrams in both figure 4a ,b shows the binding of nanodiscs (576 ru) on the antibody immobilization surface on the sensor chip. by injecting the cholera toxin b over two flow cells presented in figure 4a and 4b, the spr sensorgrams can detect the interaction of the cholera toxin b with nanodisc with or without the existence of g m1 . it has been revealed that the captured 2% g m1 -nanodiscs bound 238 ru of the cholera toxin b without binding to the capturing nanodiscs without g m1 ( figure 4b ). the measured kinetic values of the interaction are in agreement with those reported by previous studies on the interaction of the cholera toxin with the g m1 receptor embedded in different membrane systems. this, therefore, serves as a proof of concept that nanodiscs can be employed in kinetic spr studies. the nucleus envelope is composed of two bilayers (the outer nuclear membrane and inner nuclear membrane) and contains abundant ion channels, through which ions and small molecules diffuse between the cytoplasm, nucleoplasm and perinuclear (i.e., intermembrane) space. the nuclear ionic channels represent a ubiquitous structure in the nuclei in a wide range of cells, although little is known about its functional properties. to characterize nuclear ionic channels, guihard et al. [74] attempted to reconstitute nuclear envelope vesicles derived from the canine liver nuclei into a planar lipid bilayer and giant proteoliposomes. they found that the success rate of nuclear envelope fusion into planar lipid bilayers was extremely low although cardiac nuclear ionic channels were successfully incorporated into planar lipid bilayers. the detection of the nuclear ionic channels activity was not possible. such a low efficiency can be explained by the clustering of nuclear envelope vesicles, and the low density of single vesicles, as well as the presence of residual chromatin and/or nuclear proteins (histones or lamins) which would prevent fusion events with the bilayer. another approach is reconstituting nuclear envelope vesicles into giant proteolipsosmes and detecting the single ion channel by the patch-clamp technique [49] . large conductance, voltage-gated, k + and cl − selective nuclear ionic channels are characterized and plotted as a current-voltage relationship presented in figure 5a ,b respectively. it has been found that under asymmetrical 150/50 mm kcl conditions, the zero current potential for unitary currents is at 322 mv ( figure 5a ). calculated from the goldman-hodgkin-katz (ghk) flux equation, a p k +/p cl − ratio is 9.4. this value indicates the k + selectivity for this channel. in figure 5b , the cl − selective nuclear ionic channel yields a positive zero current potential of +27.3 mv, with a p cl −/p k + ratio of 80, indicative of a high cl − selectivity over k + . this suggests super fusion of the channel under asymmetrical (150/50 mm) kcl conditions. the current-voltage relationship curves indicate that the nuclear ion channels can be functionally characterized by incorporating the proteins into the giant proteoliposomes where it is possible to retain their channel activity. furthermore, the measured activities are consistent with those described for native nuclear ion channels. p-glycoprotein, the most extensively studied atp-binding cassette transporter, has been implicated in the phenomenon of multidrug-resistance in tumor cells and has been suggested to play a significant role in drug absorption and deposition. how p-glycoprotein interacts with its substrates is still unknown. functional studies are limited because of the difficulty of obtaining large quantities of stable p-glycoprotein. besides that, no atpase activity of p-glycoprotein solubilized in detergent could be detected. when p-glycoprotein is reconstituted into proteolipsomes, it has detectable atpase activity; however, the whole complex is very unstable. heikal et al. [75] have further found that p-glycoprotein reconstituted in the proteoliposomes has a half-life of less than one day. in 2009, ritchie et al. [76] performed a detailed study of drug-stimulated atpase kinase activity of p-glycoprotein using the nanodisc technology. the p-glycoprotein protein was reconstituted into both msp1e3d1 disc and liposomes in order to compare its atpase kinase activities. the results described in figure 6 demonstrate that p-glycoprotein is functionally active when reconstituted into the nanodiscs (close squares). comparing to the atpase kinase activity of p-glycoprotein reconstitution in lipsosomes (close circles), there is a twofold increase in the maximum atpase activity in the nanodiscs. this could be due to the uniform orientations of p-glycoprotein in the nanodiscs while there are two possible orientations in liposomes. these data not only show that p-glycoprotein is functionally active when reconstituted into the nanodiscs, but that it also exhibits higher specific activity than the current standard reconstitution system. figure 6 . comparsions of the atpase activity of p-glycoprotein in nanodiscs (square) and proteoliposomes (circle). open symbols: basal activity in the absence of drug; filled-in symbols: activity in the presence of nicardipine [76] . atp-binding cassette transporters utilize the energy of atp hydrolysis to transport a wide range of substrates across cellular membranes and for non-transport-related processes such as translation of rna and dna repair [77] . a member of the atp-binding cassette super family, the maltose transporter malfgk2 from e. coli, together with the substrate-binding protein male, is one of the best-characterized atp-binding cassette binding cassette transporters suitable for various reconstitution techniques. bao and fuong have reported the reconstitution of the maltose transporter in nanodiscs, in detergent and in proteoliposomes. the atpase activity of the malfgk2 complex in various environments is shown in figure 7 . the data presented in the first column of figure 7 show that the basal atpase activity for assembly in the nanodiscs and detergent (~700 nmol/min/mg) is 10-fold higher than in proteoliposomes because of the decrease in the activation energy barrier of the transporter [78] in detergent micelles and nanodiscs. however, in the presence of male, the rate of atp hydrolysis increases in all assembly conditions. this is because male captures maltose and delivers the sugar to the transporter. note that the basal atpase activity assembly in the nanodiscs dramatically increases from 700 to 2300 nmol/min/mg. the maltose alone has no effect on the basal atpase activity in the nanodiscs and detergent. however, in nanodisc and detergent, an inhibition of the atpase activity was observed in the presence of both maltose and male in the nanodiscs. this is because that maltose reduces the binding affinity of the male-malfgk 2 complex, which therefore has reduced the atpase activity. in proteoliposomes, the atpase activity (~40 nmol/min/mg) shows a further 10-fold increase in the presence of both maltose and mele in the figure. the author used another type of male mutant which binds maltose with higher affinity. this male mutant, in contrast, shows a reduction of the atpase activity in proteoliposomes which has the same effect as the nanodiscs and detergents. overall, proteoliposomes have shown a low basal atpase activity because the lipid stabilized the transporter. however, the nanodiscs have been shown to be a better medium than proteoliposomes for studying the atp hydrolysis ability of atp-binding cassette transporters. this review summarizes and compares the most up-to-date methods for reconstituting membrane proteins into model membranes. there is no superior method for reconstituting membrane proteins in the model membrane; instead two or more model membranes should be considered, depending on the particular needs of the system and the proteins of interest. in general, systems based on lipid bilayers supported on a solid substrate are still the most favored and well-developed of the methods to study membrane proteins in the bilayer. this approach allows detailed study of the fundamental properties of biological membranes and is practical to reproduce the bilayer system. on the other hand, the proteoliposome is more suitable for ion channel reconstitution in the bilayer, as well as for combination with the patch-clamp method to detect the ionic selectivity of the channel. finally the self-assembled nanodiscs system provides a robust and common means for rendering these targets soluble in aqueous media while providing a native-like bilayer environment that maintains functional activities. nanodisc technology offers another way to prepare monodisperse samples of membrane proteins in the bilayer environment, and it is emerging as the favored approach in studies concerning membrane protein complexes. biochemical and functional characterization of the membrane association and membrane permeabilizing activity of the severe acute respiratory syndrome coronavirus envelope protein lipid-protein interactions in human erythrocyte-membrane acetylcholinesterase. modulation of enzyme activity by lipids correlation between the effect of the anti-neoplastic ether lipid 1-o-octadecyl-2-o-methyl-glycero-3-phosphocholine on the membrane and the activity of protein kinase calpha weak dependence of mobility of membrane protein aggregates on aggregate size supports a viscous model of retardation of diffusion structure and phase transitions in langmuir monolayers allogeneic stimulation of cytotoxic t cells by supported planar membranes effect of colicins ia and e1 on ion permeability of liposomes direct solubilization of heterologously expressed membrane proteins by incorporation into nanoscale lipid bilayers surface enhanced raman scattering of a lipid langmuir monolayer at the air-water interface lipid monolayers: why use half a membrane to characterize protein-membrane interactions? langmuir monolayer of artificial pulmonary surfactant mixtures with an amphiphilic peptide at the air/water interface: comparison of new preparations with surfactant polymyxin b-lipid interactions in langmuir-blodgett monolayers of escherichia coli lipids: a thermodynamic and atomic force microscopy study langmuir balance investigation of superoxide dismutase interactions with mixed-lipid monolayers modern physicochemical research on langmuir monolayers structure of rhodopsin in monolayers at the air-water interface: a pm-irras and x-ray reflectivity study formation, structure, and spectrophotometry of air-water interface films containing rhodopsin proton transport by bacteriorhodopsin in planar membranes assembled from air-water interface films structural and spectroscopic characteristics of bacteriorhodopsin in air-water interface films spectroscopic and structural properties of valine gramicidin a in monolayers at the air-water interface effects of gramicidin-a on the adsorption of phospholipids to the air-water interface organization, structure and activity of proteins in monolayers monitoring of phospholipid monolayer hydrolysis by phospholipase a2 by use of polarization-modulated fourier transform infrared spectroscopy supported planar membranes in studies of cell-cell recognition in the immune system supported phospholipid bilayers formation of high-resistance supported lipid bilayer on the surface of a silicon substrate with microelectrodes supported lipid bilayer self-spreading on a nanostructured silicon surface simulations of temperature dependence of the formation of a supported lipid bilayer via vesicle adsorption simulations of lipid vesicle rupture induced by an adjacent supported lipid bilayer patch membrane lateral mobility obstructed by polymer-tethered lipids studied at the single molecule level tethered polymer-supported planar lipid bilayers for reconstitution of integral membrane proteins: silane-polyethyleneglycol-lipid as a cushion and covalent linker reversible activation of diblock copolymer monolayers at the interface by ph modulation, 1: lateral chain density and conformation polymer-cushioned bilayers. i. a structural study of various preparation methods using neutron reflectometry polymer-cushioned bilayers. ii. an investigation of interaction forces and fusion using the surface forces apparatus controlled enhancement of transmembrane enzyme activity in polymer cushioned supported bilayer membranes orientation and reactivity of nadh kinase in proteoliposomes modulation of rhodopsin function by properties of the membrane bilayer role of lipid polymorphism in g protein-membrane interactions: nonlamellar-prone phospholipids and peripheral protein binding to membranes influence of the membrane lipid structure on signal processing via g protein-coupled receptors the apoptotic protein tbid promotes leakage by altering membrane curvature modulation of ctp:phosphocholine cytidylyltransferase by membrane curvature elastic stress the role of membrane biophysical properties in the regulation of protein kinase c activity membrane lipid polymorphism: relationship to bilayer properties and protein function elastic coupling of integral membrane protein stability to lipid bilayer forces reconstitution of colicin e1 into dimyristoylphosphatidylcholine membrane vesicles the permeability of bilayer lipid membranes on the incorporation of erythrocyte membrane extracts and the identification of the monosaccharide transport proteins binding of cytochalasin b to human erythrocyte glucose transporter conformational dynamics of na+/k+-and h+/k+-atpase probed by voltage clamp fluorometry the extracellular patch clamp: a method for resolving currents through individual open channels in biological membranes lipid bilayer formation by contacting monolayers in a microfluidic device for membrane protein analysis droplet networks with incorporated protein diodes show collective properties cell-sized liposomes and droplets: real-world modeling of living cells oriented reconstitution of a membrane protein in a giant unilamellar vesicle: experimental verification with the potassium channel kcsa phospholipid phase transitions in homogeneous nanometer scale bilayer discs membrane protein assembly into nanodiscs functional reconstitution of beta2-adrenergic receptors utilizing self-assembling nanodisc technology transducin activation by nanoscale lipid bilayers containing one and two rhodopsins using nanodiscs to create water-soluble transmembrane chemoreceptors inserted in lipid bilayers atomic-force microscopy: rhodopsin dimers in native disc membranes single-molecule height measurements on microsomal cytochrome p450 in nanometer-scale phospholipid bilayer disks co-incorporation of heterologously expressed arabidopsis cytochrome p450 and p450 reductase into soluble nanoscale lipid bilayers the critical iron-oxygen intermediate in human aromatase the ferrous-oxy complex of human aromatase kinetics of dithionite-dependent reduction of cytochrome p450 3a4: heterogeneity of the enzyme caused by its oligomerization ligand binding to cytochrome p450 3a4 in phospholipid bilayer nanodiscs the effect of model membranes the atpase activity of seca is regulated by acidic phospholipids, secy, and the leader and mature domains of precursor proteins nanodiscs unravel the interaction between the secyeg channel and its cytosolic partner seca two copies of the secy channel and acidic lipids are necessary to activate the seca translocation atpase cryo-em structure of the ribosome-secye complex in the membrane environment competitive binding of the seca atpase and ribosomes to the secyeg translocon crystal structure of cholera toxin b-pentamer bound to receptor gm1 pentasaccharide self-aggregation-an intrinsic property of g(m1) in lipid bilayers ganglioside embedded in reconstituted lipoprotein binds cholera toxin with elevated affinity nanodiscs for immobilization of lipid bilayers and membrane receptors: kinetic analysis of cholera toxin binding to a glycolipid receptor patch-clamp study of liver nuclear ionic channels reconstituted into giant proteoliposomes the stabilisation of purified, reconstituted p-glycoprotein by freeze drying with disaccharides chapter 11-reconstitution of membrane proteins in phospholipid bilayer nanodiscs abc transporters, mechanisms and biology: an overview discovery of an auto-regulation mechanism for the maltose abc transporter malfgk2 the authors gratefully acknowledge financial support from the australian research council (arc). hhs is an arc super science fellow and tl is an arc federation fellow. tl and lm were awarded the arc super science fellowships and grant (fs110200015). we thank victoria hewitt for her critical reading of the manuscript. key: cord-287348-00yaxpkp authors: martinez, maria jose abad; olmo, luis miguel bedoya del; benito, paulina bermejo title: antiviral activities of polysaccharides from natural sources date: 2005-12-31 journal: studies in natural products chemistry doi: 10.1016/s1572-5995(05)80038-9 sha: doc_id: 287348 cord_uid: 00yaxpkp abstract the ever increasing resistance of human pathogens to current anti-infective agents is a serious medical problem, leading to the need to develop novel antibiotic prototype molecules. in the case of viruses, the search for antiviral agents involves additional difficulties, particularly due to the nature of the infectious viral agents. thus, many compounds that may cause the death of viruses are also very likely to injure the host cell that harbours them. natural products are increasingly appreciated as leads for drug discovery and development. screening studies have been carried out in order to find antiviral agents from natural sources, and the occurrence of antiviral activity in extracts of plants, marine organisms and fungi is frequent. the evidence indicates that there may be numerous potentially useful antiviral phytochemicals in nature, waiting to be evaluated and exploited. in addition, other plants, not previously utilized medicinally, may also reveal antivirals. among natural antiviral agents, recent investigations have reconsidered the interest of phyto-polysaccharides, which act as potent inhibitors of different viruses. this chapter will illustrate a variety of antiviral polysaccharides from natural sources since 1990, with the aim of making this matter more accessible to drug development infectious diseases account for one-third of all deaths worldwide. although the last decade has yielded significant advances in the treatment of infectious diseases, new therapies for viral, fungal, bacterial and parasitic infections are needed [1] . viruses are responsible for a large proportion of the morbidity and mortahty experienced worldwide. these infectious agents consist of a core genome of nucleic acid, dna or rna (nucleoid) contained in a protein shell (capsid) and sometimes surrounded by a lipoprotein membrane (envelope). some genera of viruses are known to cause human infections and include the following: adeno, pox and herpesviruses: herpes simplex virus type 1 and 2, varicella-zoster, cytomegalovirus, epstein-barr virus; papillomaviruses (papillomas, cancer); parvoviruses (erythema infectiosum); dna-viruses (e.g., hepatitis b); (+/-) rna viruses: reo-and rotavirus; (-) rna viruses: influenza, parainfluenza, measles, respiratory syncytial, vesicular stomatitis, rabies virus and togaviruses (rubella, yellow fever); retroviruses (e.g., human immunodeficiency virus, the causative agent of acquired immunodeficiency syndrome); and other several rna viruses such as arenaviruses (lymphocytic choriomeningitis), bunyaviruses (encephalitis), coronaviruses (upper respiratory infections) and picornaviruses (poliomyelitis, diarrhoea). most successful anti-infective agents inhibit essential steps in metabolic processes required by the pathogen but absent in the host. hov^ever, viruses cannot replicate independently. they must enter cells and use the cellular energy-generating, dna-or rnareplicating and protein-synthesizing pathways of the host to achieve viral replication. for this reason, in the case of viruses the search for antiviral agents is very hard since metabolic differences are not available: viruses utilize the host's protein synthesis leaving only some aspects of nucleic acid synthesis and macromolecule processing distinct from the host's metabolism. the identification of a retrovirus, human immunodeficiency virus, as the causative agent of acquired immunodeficiency syndrome, the steadily increasing incidence of various viral infections caused by viruses in immunodeficient patients, e,g., herpes simplex virus, varicella-zoster virus, cytomegalovirus and epstein-barr virus, the increasing evidence for the pathogenic role of a number of viruses, e.g., human papilloma virus in the pathogenesis of primary hepatocellular carcinoma, and the socioeconomic impact of viral infections of the respiratory (influenza, adeno-, corona-and rhinoviruses) and gastrointestinal tract (rotaviruses) have all been important factors in boosting the search for new antiviral agents and new modalities of antiviral chemotherapy. although many compounds with potent antiviral activity in cell cultures and in experimental animals have been detected, at present only several molecules and a-interferon have been approved by the health authorities for therapy of viral infections in humans. among these antiviral substances are several natural compounds isolated from plants used in traditional medicine, including polysaccharides [2] [3] [4] . polysaccharides (ps) constitute a stmcturally diverse class of biological macromolecules with a wide range of physicochemical properties, which are the basis for different applications in the broad field of pharmacy and medicine [5] [6] [7] [8] , several hundred natural ps are currently known and provide one of the richest and oldest reservoirs of structurally and functionally diverse biopolymers. ps constitute important members of the family of industrial water-soluble polymers. besides the classical applications of these biopolymers in industry and pharmaceutical practice, the relatively new field of pharmacologically active polymers will be discussed. ps from plants and other natural sources have long been known to exert antitumour, immunomodulatory, anticoagulant and other types of biological activity, including antiviral activity. the importance of the plant kingdom as a source of new antiviral substances will be illustrated by presenting a survey on natural-derived antiviral ps. in recent years, natural and synthetic polymers of a carbohydrate nature were proved to be selective inhibitors of several enveloped viruses, including such human pathogens as human immunodeficiency virus, herpes simplex virus, human cytomegalovirus, influenza virus and respiratory syncytial virus. recent efforts have been directed at the development of polysaccharidic molecules as selective inhibitors of different classes of viruses [9, 10] . in this search, the following molecular targets were envisaged: for dna viruses in general, the viral dna polymerase; for herpes simplex virus and varicella-zoster virus, the viral dna polymerase via a specific phosphorylation by the viral 2'deoxythymidine kinase; for (+/-) rna and (-) rna viruses, sadenosylhomocysteine hydrolase, a key enzyme in transmethylation reactions required for the maturation of viral mrna; for retroviruses, reverse transcriptase as an initiator of virus replication and/or cell transformation; and for several enveloped viruses (e.g., retro-, herpes-and rhabdoviruses), virus adsorption to the outer cell membrane. this review deals with antiviral ps compiled from several sources during the past decade. under the respective titles, we offer some brief descriptions of the most important global viral infections that are caused either by individual viruses or by groups of related viruses. they are restricted to those generally considered important in human and veterinary medicine and about which reports on active antiviral ps are recorded in the literature. acquired immunodeficiency syndrome (aids) is a pandemic immunosuppressive disease which results in life-threatening opportunistic infections and malignancies. in 1996, the number of aids infections was 23 million and 1.5 million people (half of them in africa) were killed by this disease worldwide. in order to combat human immunodeficiency virus (hiv), the causative agent of aids, enormous amounts of time and money have been dedicated to research into compounds which can be developed as therapeutic agents. hiv is a lentivirus which replicates within critical cells of the immune system, particularly cd4 t-cells and monocyte/macrophages, leading to a progressive loss of helper t-cells and profound immunosuppression. this condition is known as aids. without treatment, the cd4 t-lymphocytes of an infected patient are reduced markedly so that the patient is susceptible to a wide range of opportunistic infections, and ultimately dies. since this retrovirus, designated hiv, has been clearly identified as the primary cause of this disease, numerous compounds, also including plant-derived substances, have been evaluated for their inhibitory effects on hiv replication in vitro. furthermore, many plant products are being used by patients with aids in some countries without any scientific proof that they possess anti-hiv activity. several reviews on natural products for the chemotherapy of hiv infections have been recorded in the literature [11] [12] [13] [14] [15] [16] [17] [18] [19] . carbohydrates were among the natural molecules capable of treating hiv infection. various ps, including sulphated ps, have been found to be anti-hiv active substances of many antivirally active plant extracts, all of which are medicinal plants used in traditional medicine as anti-infectives. for example, a ps (mar-10) was isolated from the aqueous extract of the plant hyssop officinalis l., which was found to inhibit hiv-1 replication as demonstrated by the inhibition of hiv-1 p24 antigen and syncytia formation [20] . from aspalathos linearis burm., a popular medicinal plant in south africa, europe and japan, a ps with strong anti-hiv activity was isolated [21, 22] . this compound almost completely inhibited the binding of hiv-1 to mt-4 cells. the major sugar components of this purified ps were found to be glucose, galactose, mannose and xylose. premanathan et al [23, 24] investigated the ps extracted from rizophora apiculata blume and rizophora mucronata poir. in cell culture systems for their activity against human and simian immunodeficiency viruses (siv), both compounds inhibited hiv-1, hiv-2 or siv strains in various cell cultures and assay systems. it was found that these ps consisted mainly of neutral sugars and uronic acids. in a screening programe of thai plants for anti-hiv activity, it was found that 114 extracts of 81 species belonging to 32 families showed activity [25] . of the effective samples, the extracts of merremia peltata (l.) merrill were the most active. most of the anti-hiv agents were found to be anionic ps. furthermore, sulphated derivatives of paramylon, a (1-3)-p-d-glucan from euglena gracilis klebs. significantly inhibited the cytopathic effect of hiv-1 and hiv-2 [26] , while two naturally occurring ps isolated from the tropical climbing shrub ipomoea cairica (l.) sweet were found to strongly inhibit replication of hiv-1 in vitro [27] . according to de clercq [28] , the replicative cycle of hiv comprises several steps that could be considered adequate targets for chemotherapeutical intervention: virus entry, viral adsorption, virus-cell fusion, reverse (rna -> dna) transcription, proviral dna integration, viral (dna -> e^a) transcription (transactivation), viral (mrna -> protein) translation, virus release, viral assembly, budding and maturation. the most notable difference between hiv replication and other retroviruses is the intricate control of hiv gene expression by viral and cellular factors [29] . possible mechanisms by which hiv kills infected cells include the formulation of multinucleate syncytia, cytopathic components within the virions themselves, and interaction between viral envelope proteins and the cd4 molecule on the cell surface. three hiv enzymes are essential to the life cycle of the virus: hiv reverse transcriptase is crucial for viral replication; hiv protease processes viral polyproteins into fonctional enzymes and structural proteins, thereby facilitating maturation and infectivity of the virion particles; hiv integrase mediates hiv integration into the host chromosome. the chemotherapeutic strategies have therefore been focused on the development of inhibitors of these retroviral enzymes. recently, it has been reported that biological membranes arising from hiv-induced cell fusion, as well as syncytium formation between infected and non-infected cells are interesting approaches in research for a new hiv therapy [30] . natural sulphated ps such as dextran sulphate, pentosan sulphate, chondroitin sulphate and heparin have long been recognized as effective anti-hiv agents [31] [32] [33] [34] [35] . these compounds target the interaction between the viral envelope glycoprotein gpl20 and the cd4 receptor and, as a consequence, they inhibit not only vims adsorption to the cells but also virus-induced syncytium (giant cells) formation [36] [37] [38] [39] [40] [41] [42] . the inhibitory effect of dextran sulphate and its congeners on viral binding, viral replication and syncytium formation appears to be mediated by a specific interaction with the v3 region of gpl20. in addition, sulphated ps may also directly interfere with the binding of hiv particles to the heparin sulphate proteoglycan of the cell surface, whether or not this process occurs independently of, or cooperatively with, the viral envelope cd4 receptor interaction. this class of antiviral agents exhibits several unique properties that are not shared by other currently known antiviral agents: remarkable broadspectrum antiviral activity against hiv-1, hiv-2 and a series of other enveloped viruses; the ability to inhibit syncytium formation between hiv-infected and normal cd4 t-lymphocytes, a mechanism that drastically enhances hiv infectivity and a low induction of viral drugresistance [43] . it should be noted that sulphated ps owe their anti-hiv activity to the presence of the sulphate groups, which in turn are responsible for the inhibition of virus-cell binding. dextran is a highmolecular-weight ps consisting predominantly of a (1 -> 6) linked dglucose units. dextrans can differ in chain length and in degree of branching. the branching occurs via a (1 ^3) and a (1 -> 4) branch points. dextran fractions of different average molecular weight were obtained by partial hydrolysis. these different fractions were sulphated to obtain dextran sulphates of different molecular weight. busso and resnick [44] investigated the effects of three molecular weight ranges of dextran sulphate on five different hiv isolates. the higher molecular weight range of dextran sulphate showed the most potent activity as assessed by a quantitative syncytium formation assay. however, dextran sulphate is poorly adsorbed after oral administration and upon intravenous administration produces thrombocytopenia, so that there is little, if any, evidence for the in vivo efficacy of this compound and more generally of sulphated ps against hiv infection [45] . however, double-blind placebo-controlled clinical pilot trials in advanced hiv disease are being conducted with these compounds [46] . in summary, these compounds offer great promise as candidate drugs for the chemotherapy of hiv infections, and novel sulphated ps which have proved to be potent and selective inhibitors of hiv in vitro are being chemically synthesized [47] [48] [49] [50] [51] [52] . on the other hand, although several groups have reported that sulphated ps are potent and selective inhibitors of hiv, their therapeutic application is however limited by their anticoagulant activity. in view of possible improvements in therapeutic potential, a number of heparin derivatives with reduced anticoagulant activity were studied for their inhibitory activity in an hiv-dependent syncytium formation assay [53] . the most pronounced anti-hiv activity was observed with 30% succinylated standard heparin and 100% succinylated low molecular weight heparin. similarly, and in order to increase the ratio of anti-hiv activity to anticoagulant activity, selectively substituted sulphated ps with oh and/or cooh groups were chemically prepared [54, 55] . this group comprises a family of heterogeneous carbohydrates composed of long, unbranched ps modified, for example, by sulphations and acetylations. the acetylated derivatives are more active as inhibitors of hiv-induced giant-cell formation. furthermore, several soluble derivatized dextrans with different percentages of carbomethyl, benzylamide and sulphonate/sulphate groups were also evaluated for possible inhibitory effects on hiv-1 infection, and from the results obtained, their use as anti-hiv therapeutic agents can be proposed [56] . other natural sources of anti-hiv sulphated ps include algae and other marine organisms. sulphated ps have been found in a variety of marine animals, plants and microorganisms [57, 58] . aqueous extracts of many marine invertebrates have exhibited some activity in the national cancer institute's primary screen for anti-hiv cytopathicity [59] . carrageenans and fucoidan are sulphated ps extracted from red seaweed and brown algae, which have shown potent inhibitory activity against different viruses including hiv. for example, fucoidan, a complex sulphated ps from the alga fucus vesiculosus l. was found to inhibit hiv in vitro, presumably through a direct interaction of the ps with the hiv binding site of the target cells [60] . the aqueous-soluble extracts from this alga, a common littoral alga of the coast of the northern atlantic, the pacific ocean and the baltic sea, inhibited the activity of hiv reverse transcriptase enzyme as well as hiv-induced syncytium formation. beress et al [61] reported a new procedure for the isolation of the anti-hiv ps from this marine alga. a novel sulphated ps named calcium spirulan has been isolated as an antiviral principle from spirulina platensis (nordst.) geitl., a blue-green alga growing in some african and central and south american lakes rich in salts [62] [63] [64] [65] . chemical analyses of calcium spirulan suggest that it contains rhamnose, ribose, mannose, fructose, galactose, xylose, glucose, glucuronic acid and galacturonic acid. other sulphated ps from marine sources have demonstrated antiviral activities against hiv, blocking viral replication in cell culture without any toxicity to the host cells. examples include sulphated cell-wall ps from the mediterranean red alga asparagopsis armata harvey [66] , from the marine microalga cochlodinium polykrikoides blooms [67] , fiicose, the main component sugar of the ps isolated from the brown alga sargasum horneri (turner) c. agardh [68] and sargasum muticum (yendo) fensholt. [69] , sulphated ps from brazilian marine algae such as laminaria abyssalis ab joly & ec oliveira [70] , and from tropical marine algae of the codiaceae family [71] , and new sulphated p-galactans from the marine clam species meretrix petechialis lamarck [72] . other natural sources of anti-hiv sulphated ps include fiingi such as ganoderma lucidum (fr.) karst. [73] and lentinus edodes (lem.) mycelia [74] . inhibition of hiv-reverse transcriptases (hiv-rt) is currently considered a usefiil approach in the prophylaxis and intervention of aids and natural products have not as yet been extensively explored as inhibitors of this enzyme [75, 76] . furthermore, the mechanisms of action of sulphated ps may not only be due to the inhibition of virus cell adhesion, but also to the inhibition of hiv-rt [13, 15] . herpes infections are ubiquitous. approximately, 16-35%, 40-80% and >90% of the population are sero-positive for, or infected by herpes simplex virus type i (hsv-1), herpes simplex virus type ii (hsv-2) and varicella-zoster virus, respectively. more alarmingly, over the past decade, the incidence and severity of infections caused by hsv have increased due to the growth in number of immunocompromised patients produced by aggressive chemotherapy regimens, expanded organ transplantation and a greater occurrence of hiv infections. unfortunately, prolonged therapies with acyclovir, the most successful antiherpetic drug, have resulted in some undesirable complications and also induced the emergence of drug-resistant viruses. with this change in disease pattern, and the increase in drug use frequency, acyclovir-resistant hsv infections have emerged. infections with hsv range from simple cold sores and fever blisters to severe central nervous system disorders. development of effective antiviral medications has made prompt recognition important in primary care practice. appropiate therapy can significantly reduce both the medical and psychosocial ramifications of herpes infections and can greatly improve the quality of life of many patients [77] . thus, there is an urgent need for novel anti-hsv agents, especially those with a different mode of action from acyclovir. for the past decades, in addition to a variety of synthetic antiviral drugs with different molecular targets, a large number of phytochemicals have been recognized to control infections caused by viruses belonging to the herpesviridae family. ethnopharmacological screenings of medicinal plants from all over the world have led to the selection of several extracts which are active against herpes viruses. among natural antiviral agents, recent investigations have revived the interest in phyto-ps, which act as potent inhibitors of different enveloped viruses, including members of herpesviridae. for example, a neutral ps extracted from sclerotium glucanicum halleck., namely scleroglucan, revealed promising antiviral activity [78] . these ps are composed of a p-1,3-linked glucopyranose backbone with single p-l,6-linked glucopyranosyl branches every third subunit. the blockage on hsv infection takes place during the very early phases of the viral multiplication cycle, since the greatest inhibitory effect occurred when it was added during the attachment step. as a result of the intensive search for antiviral substances from medicinal plants, antiviral activity against hsv was found in extracts from cedrela tubiflora bertoni. leaves [79] , from prunella vulgaris l., a perennial plant commonly found in china, the british isles and europe [80] and from trichilia glabra l. leaves [81] . phytochemical studies indicate that these plants contain anionic ps as active constituents which may inhibit hsv by competing for cell receptors as well as by some unknown mechanisms after the virus has penetrated the cells. furthermore, the in vitro antiviral activity demonstrated by extracts of the medicinal plant achyrocline flaccida (weinm.) d.c. on hsv-1 is exerted early during viral replication, essentially during viral adsorption to host cells [82] . a bioguided purification process indicated that negatively charged ps were responsible for this antiviral activity. among natural antiviral agents of a carbohydrate nature, recent investigations have also revived interest in sulphated phyto-ps such as carrageenans and fucoidan from seaweed. sea algae represent a very interesting source of potential antiviral compounds, particularly the watersoluble sulphated ps which are abundant constituents of the cell wall. these compounds act as potent inhibitors of different enveloped viruses, including members of herpesviridae, and their activity is linked to the anionic features of the molecule which hinder the attachment of viral particles to host cells. for example, carrageenans are sulphated galactans that can be extracted from certain red seaweeds. they comprise a broad range of structures and can be divided into two families: the k-family, defined by the presence of a c4-sulphate group on the p-d-unit, and the x-family, characterized by the sulphate on c2 and constituted by all the variations of the ^.-structures [83] . investigations have detected antiviral activity in a significant number of algae from various marine environments such as california, united kingdom, the mediterranean, india and japan [84] . in the course of a screening study on the biological properties of natural marine products, diverse carrageenans isolated from the red seaweed gigartina skottsbergii setch. et gard. have proved to be potent inhibitors of hsv-1 and -2 in vitro [85] . mode of action studies are consistent with the carrageenans having a major effect on the attachment of virus to the cells. adsorption of hsv-1 is primarily mediated by the envelope glycoprotein gc, which binds to heparan sulphate residues present on the proteoglycans on the surface of target cells. antiherpetic activity was directly correlated to the amount of a-d-galactose 2,6-disulphate residues in the natural carrageenans. carrageenans were also isolated from chilean samples of stenogramme interrupta (c. ag.) mont., a red seaweed from california [86] . in the course of screening for antiviral properties in sulphated ps isolated from marine algae of the south american coast, carlucci et ah [87] reported the antiviral activity of mannans and xylogalactans isolated from the red seaweed nothogenia fastigiata turner (lam.), and a sulphated galactan from pterocladia capillacea (gmelim) barnet & thuset. hsv-1 and -2 were the most sensitive viruses of these compounds due to an inhibition of virus binding. structural analysis of two xylomannans extracted from nothogenia fastigiata was carried out [88, 89] . the results are consistent with the general pattern previously reported for other xylomannans of the same system, a(l -> 3)-linked dmannans 2-and 6-sulphated and with single stubs of p(l -> 2)-linked dxylose, but one of the new samples contains a significant amount of 2,6disulphated units. the presence of sulphate groups in the molecule was essential to the antiviral properties of these ps [90] . the antiviral activity of sulphated ps is known to increase with molecular weight or the degree of sulphation. however, sulphated ps are generally endowed with anticoagulant properties that may hamper their usefulness as antiviral drugs. duarte et al [91] reported the inhibitory effect of sulphated galactans from the marine alga bostrychia montagriei harvey. the results of the activated partial thromboplastin time assay and the thrombine time assay indicated that three natural sulphated ps have very low anticoagulant activity, confirming that there is no relation between the antiviral and anticoagulant properties. anti-hsv sulphated ps have also been isolated from other seaweeds such as rhamnan sulphate from monostroma latissimum wittrock [92] , and calcium spirulan from the blue-green alga spirulina platensis [62] . lee et al. [93] initiated studies into the structure-activity relationships of calcium spirulan. calcium ion binding with the anionic part of the molecule was replaced with various metal cations. replacement of the calcium ion with sodium and potassium ions maintained anti-hsv-1 activity while divalent and trivalent cations reduced the activity. the cell wall sulphated ps of the red microalga porphyridium spp. honey exhibited impressive antiviral activity against hsv-1 and -2 both in vitro (cell culture) and in vivo (rats and rabbits) [94] . it seems that this ps is able to inhibit viral infection by preventing adsorption of the virus into the host cells and/or by inhibiting the production of new viral particles inside the host cells [95] . novel fiican sulphates with anti-hsv activity were also isolated from the hot water extract of an edible brown alga sargassum horneri [96] and from the brown seaweed leathesia difformis (linnaeus) areschong [97] . other natural sources of anti-hsv ps include fimgi, e.g., various protein bound ps isolated from ganoderma lucidum, a basidiomycetous fungus used to treat human diseases in oriental folk medicine [98] . the possible mode of antiviral activity of these ps seems to be related to their binding with hsv-specific glycoproteins responsible for attachment and penetration, impeding the complex interactions of viruses with cell plasma membranes [99] [100] [101] . furthermore, different semisynthetic ps were evaluated for their inhibitory effect on in vitro replication of hsv-1 and -2 [102] [103] [104] . some neutral and negatively charged carbohydrates were able to inhibit viral infection by interfering mainly with the adsorption process. the in vitro and in vivo effects of sulphated ps were also investigated against the pseudorabies virus (suid hsv-1), the most notable of which is porcine hsv which has a well-documented history of epizootic infections, especially in europe [105] . in vitro experiments revealed that sulphated ps significantly reduced the number of lytic plaques, but in vivo only heparin protected mice against the pseudorabies virus. in terms of their biological and pathogenetic properties, the herpes viruses fall naturally into several subfamily groupings, including cytomegalovirus (cmv), although detailed classification is at present premature. nevertheless the cmv clearly constitute a group of their own with internal consistency. human cmv is, together with hsv-1, one of the agents responsible for opportunistic infections in hiv-infected people. as can be seen in the present review, sulphated ps show antiviral activitiy against enveloped viruses in vitro. it has been suggested that these antiviral mechanisms depend on their polyanionic properties, which interact with the positively charged amino acid sequence of viral envelope glycoproteins. natural sulphated ps can act as potent inhibitors of cmv. the cell wall mucilages of seaweeds are known to be rich in sulphated ps with potential anti-cmv activity. recently, blinkova^/a/. [106] reviewed information on spiridina platensis, a blue-green alga with diverse biological activity. preparations obtained from this alga have been found to be active against several enveloped viruses, including cmv. it was revealed that calcium spirulan, a sulphated ps isolated from spirulina platensis, selectively inhibited the penetration of the virus into host cells [62] . retention of molecular conformation by chelation of calcium ion with sulphate groups may be indispensable to its antiviral effect. the antiviral activity of a polysaccharidic fraction obtained from another red seaweed, nothogenia fastigiata, was also reported [107] . its mode of action against cmv could be ascribed to an inhibitory effect on virus adsorption. other natural sources of sulphated ps include brown algae. a sulphated polysaccharide with potent anti-cmv activity was isolated from the brown alga sargassum horneri [68] . time-of-addition experiments suggested that it inhibited not only the initial stages of viral infection, such as attachment to and penetration into host cells, but also later replication stages after virus penetration. fractions of fiicoidan, another polysaccharide isolated from the brown seaweed leathesia difformis were also found to be selective antiviral agents against human cmv [97] . these compounds offer great promise as candidate drugs for the chemotherapy of cmv infections, and novel sulphated ps are being chemically prepared [108] . ps from terrestrial plants have also been reported as anti-cmv agents. for example, ps from three plant species. astragalus brachycentrus d. c, astragalus echidnaeformis sirjaev and sterculia urens roxb., which are devoid of in vitro antiviral activity, were evaluated in mouse models of murine cmv infections [109] . treatment with the compounds needed to be started one day prior to virus inoculation for maximum protective benefit. treatments starting after virus inoculation were ineffective. the mannose-specific plant ps from the orchid species cymbidium hybrid cym., epipactis helleborine (l.) crantz. and listera ovata (l.) r.br. svenska are potent and selective inhibitors of human cmv in vitro [110] . they presumably interact at the level of virion fusion with the target cell. papillomaviruses are members of the papopavirus family and are distinguished from other members by virtue of their association with a variety of warts in different parts of the body. some types have been implicated in genital warts and cervical carcinomas, while others seem to be associated with other distinctive warts elsewhere. no generally effective control is available, although potentially dangerous lesions can be removed by cryosurgery or laser treatment. however, some medicinal plant preparations have been reported to be beneficial; conceivably these may work by promoting healing or stimulating immune responses, rather than directly inhibiting the virus. natural high-molecular weight sulphated or sulphonated ps, such as cellulose sulphate and dextran sulphate, may be useftil non-toxic microbicidal compounds that are active against a variety of sexuallytransmitted disease agents, including bovine papillomavirus type 1 and human papilloma virus type 11 and type 40 [111] . hepatitis b virus (hbv) is widespread throughout human populations, specially in asia and africa, and it has been estimated that over 200 million carriers exist, some of whom are eventually expected to develop liver carcinoma or cirrhosis. hbv shows a strict tropism for liver hepatocytes in which it displays a protected replication with resultant foci of liver necrosis. the virus is a member of the hepadnaviridae, along with several other species, and it replicates by a mechanism which appears to be unique to this family. in contrast, hepatitis a virus is a picornavirus and the hepatitis d agent appears to be a viroid-like rna enclosed within a hepatitis b capsid, and consequently depends upon its association with the hbv for its spread and survival. control may be effected by passive immunization (with hyperimmune globulin) or by various types of vaccines which are currently being developed and improved. specific chemotherapy has not been consistently successful, but in some countries (e.g., india and china), plant extracts have provided some success. among natural antiviral agents of carbohydrate nature, sulphated ps such as x and k carrageenans showed a potent inhibitory effect on the replication of hbv in the human hepatoma cell line plc/prf/5 [112] . the two types of carrageenans resulted in concentration-dependent reduction of hbv-antigen expression and hbv infectivity, emerging as promising candidates for chemotherapy of acute hepatitis. human rotavirus (hrv), a member of the reoviridae, is a non-enveloped virus which is the major etiologic agent of severe dehydrating gastroenteritis in children worldwide. for the treatment of rotavirus gastroenteritis, intravenous fluid administration has been used successfully for dehydration from diarrhoea. however, in the case of severe inpatients and immunocompromised hosts who are suffering from prolonged diarrhoea and fever, virus-specific treatment will be necessary if possible. several compounds, biomaterials and plant extracts have been found to be inhibitory for hrv of some species in vitro. for example, extracts of stevia rebaudiana bertoni, a family member of chrysanthemum originating from paraguay in south america, inhibited the replication of all four serotypes of hrv in vitro [113] . binding assays with radiolabeled purified viruses indicated that the inhibitory mechanism of this plant extracts is the blockage of virus binding. the inhibitory components of stevia rebaudiana were found to be heterogeneous anionic ps with different ion charges. influenza continues to have a significant impact on public health. annually, 20,000 deaths and 100,000 hospitalizations are attributed to "flu" in the united states alone. airborne transmission, facile viral mutation, vaccine shortages, and actual and perceived side effects and limitations of both vaccines and prophylactic drugs contribute to the drive for new therapies and preventive medicines for influenza. research during the last fifteen years has elucidated many of the mechanisms by which the influenza virus invades, captures and mobilizes the replication capabilities of a host cell, providing new targets in the search for antiviral treatments. for the past decades, besides a variety of synthetic antiviral drugs with different molecular targets, a large number of phytochemicals have been recognized to control infections caused by the influenza virus. serkedjieva et al [114] reported the antiviral activity from a lyophilized infusion from flowers of sambucus nigra l., aerial parts of hypericum perforatum l. and roots of saponaria officinalis l. the preparations contain ps which could be responsible for their antiviral properties. reports on the anti-influenza virus activity of natural ps are recorded in the literature. from a pine cone extract of pinus parviflora sieb. et zucc, an acidic polysaccharide was isolated [115, 116] . this compound showed significant inhibition of both the viral protein synthesis in infected cells and virion-associated rna-dependent rna polymerase activity. in animal models in vivo, most mice inoculated intranasally or intracerebrally with lethal doses of the influenza virus a/wsn/33 died within 12 days. however, the infectivity of the virus that had been preincubated with a polysaccharide prepared from cones of pinus parviflora was significantly reduced [117] . in 1991, sakagami et a/. [118] reviewed the potential antiviral efficacy of natural polysaccharidic-related materials isolated from the pine cone extracts. sulphated ps, potent antiviral agents, were also evaluated in vitro as inhibitors of influenza virus replication [119] . the fact that the sulphated ps are inhibitory to some myxoviruses and retroviruses but not to others seems to depend on the composition of the amino acid sequences of the viral envelope glycoproteins that are involved in virus-cell binding and fiision [120] . as can be seen in the present review, other natural sources of antiviral sulphated ps include the marine environment. sulphated and nonsulphated ps with anti-influenza activity have been isolated from marine sources such as the green marine alga ulva lactuca l. [121] , the japanese sea alga crenomytilus grayanus dunkei. [122, 123] , the blue-green alga spirulina platensis [106] , the red seaweed nothogenia fastigiata [107] and the marine microalga cochlodinium polykrikoides [67] . novel marine ps which have proved to be potent and selective inhibitors of the influenza virus in vitro are being chemically synthesized [124, 125] . the measles virus (mv) is a paramyxovirus which has been associated with several chronic diseases. since the advent of mass immunization campaigns, the incidence of measles has decreased dramatically in many developed countries. this is not the case elsewhere, however, where the virus still takes its toll in large numbers, especially in malnourished or immunocompromised individuals. secondary bacterial infections are prevalent in these populations. although most infections are relatively short-lived and innocuous in healthy individuals, encephalitis can develop in approximately 0.1% of cases; hence vaccination is desirable. following respiratory infection, the virus readily invades local lymphoid tissues and gains access to the blood, from where it disseminates widely in the body. there has not been much demand for chemotherapy; vaccination seems to be the choice. no really effective antiviral has been evaluated, although some plant compounds have been shown to inhibit mv replication effectively, such as ps from the blue-green alga spirulina platensis [62] . rabies has long been recognized as a scourge of livestock with occasional and often fatal intrusions into humans and their pets. initially the virus gains access to muscle, sensory organs or skin, and there replicates in local unmyelinated (sensory) nerve fibers. many layers of epithelial cells are susceptible to the virus but the principal target is the unprotected neuron. the brain is where most damage is done, resulting in the familiar psychomotor disturbances. in addition, the virus spreads into salivary glands (by axoplasmic flow again), from where it is secreted from the asinar mucous cells and transmitted to the victim. the objective of much research on the rabies virus has been the development of better vaccines and therapeutic measures, some of them from natural sources. for example, different natural polymeric carbohydrates inhibited rabies virus infection in chicken-embryo-related cells by interfering with the virus adsorption process [126] . the charge density and the polymeric backbone of the molecules seem to play a role in influencing the antiviral properties, whereas other features such as the sugar moieties do not appear to be relevant. rubella is the sole member of the rudivirus genus in the togavirus family. the virus is transmitted by the respiratory route, and multiplies in upper respiratory tissues from where it gains access to the blood, accompanied sometimes by a characteristic rash and other symptoms. the infection may be more severe in pregnant women. vaccination programmes are in place in many countries, and the belief is that the virus will eventually be brought under control. although there seems to be no apparent role or need for specific antiviral therapy, reports on the antirubella activity of natural products and extracts have been reported [57] . for example, the natural carbohydrate scleroglucan, three sulphate derivatives and dextran sulphate were investigated for their inhibitory effect on rubella virus infection on vero cells [127] . the results indicated that ps blocked a step in virus replication subsequent to virus attachment, such as internalisation and/or uncoating. bunyavirus sandfly fever sicilian virus (sfsv) is a phlebovirus, a member of the bunyaviridae family, which cause acute, incapaciting but self-limiting diseases in man, and which have had a major impact in europe, the middle east and africa. sfsv is a virus closely related to other viruses which are considerably more pathogenic both in humans and animals, such as the african swine fever virus (asfv) and the crimean-congo haemorrhagic fever virus (cchfv). the asfv is a highly contagious bunyavirus infection of pigs which is clinically indistinguishable from the unrelated hog cholera virus. since 1957, epidemics have been recorded intermittently in several european countries bordering the mediterranean, in the caribbean, and in brazil, and more recently in other european countries and parts of africa. although pigs appear to be the only species infected naturally, the virus can be adapted to grow in a variety of other cell types and experimentally infects goats and rabbits. in view of this, it seems worthwhile to consider the possibility of its natural persistence in animals other than swine and man. transmission of asfv usually occurs through the respiratory route. following inhalation, the virus invades and attacks local lymph nodes and the endothelium of blood vessels, with the resuh that high titers of virus circulate in the blood and lymph, and eventually in various secretory fluids. attempts have been made to produce vaccines, but without much success. in any case, the virus mutates frequently in the wild and crossprotection of animals is not complete. since the virion contains several enzyme activities, and the dna can probably code for more in the infected cell, the possibility of specific chemotherapy, along the lines of antiherpes chemicals, should be profitable. several studies have been undertaken to develop drugs which could be used for treatment of fever infections caused by viruses belonging to the bunyaviridae family, including natural ps [128, 129] . antiviral activity was estimated by the reduction of the cytophatic effect of sfsv on infected vero cells. several ps, such as carrageenans, fucoidan, dextran sulphate and pentosan polysulphate caused a concentration-dependent reduction in the virus yield. fabregas et al [130] screened several extracts from marine microalgae for in vitro inhibition of the replication of asfv. that this inhibition could be due to sulphated ps was suggested because the same pattern of viral inhibition was obtained by using exocellular extracts from microalgae enriched in these compounds and/or dextran sulphate of high molecular weight. other natural ps should be considered for the potential treatment of significant human infections caused by bunyaviruses. the mouse model of punta toro virus, a phlebovirus member of the bunyaviridae family, is a model for studying the treatment of rift valley fever infection. tragacanthin ps from astragalus brachycentrus and astragalus echidnaeformis plants caused reduction in mortality, liver infection scores, liver and spleen virus titers, and serum transaminases in treated mice [131] . poliomyelitis is not the scourge that it once was, thanks to improved hygienic practices which have effectively blocked the spread of wild-type polioviruses, especially in developed countries, and thanks to the widespread use of vaccines. the viruses, like other enteroviruses, are transmitted by the fecal-oral route; following ingestion, they replicate in various cell types in the pharynx and small intestine (they are quite stable to stomach acids) and gain access to the circulation. from there, they disseminate and occasionally gain access to the central nervous system, where they may produce the characteristic lesions leading to poliomyelitis. control of virus spread accompanied by vaccination continues to provide the best means of alleviating poliomyelitis. the use of antivirals seems to have less application than for many other viral infections, although the poliovirus continues to serve as a useful laboratory model for antiviral screening. the plant kingdom and seaweeds may be a source of potentially useful and interesting antiviral compounds against polioviruses. for example, anti-poliovirus activity was detected in a polysaccharidic-rich fraction from extracts of several korean seaweeds [132] , and from the leaves of the meliaceae tree trichilia glabra [81] . other compounds of carbohydrate nature with antiviral activity against other viruses have been isolated from natural sources. several compounds belonging to different classes of sulphated ps were evaluated for their inhibitory effects on the replication of the arenavirus junin and tacaribe in vero cells [133, 107] . very potent and selective inhibitors were the sulphated ps dextran sulphate, ^.-carrageenan, fucoidan, heparin and pentosan polysulphate. examples also include aloe polymannose, a high mannose purified from the aloe barbadensis miller plant, which showed activity in enhancing antibody titers against coxsackievirus b3-induced myocarditis in murine models of the disease [134] , and fungal ps which are active in vivo in sendai virus infection [135] . although relatively little work has been done on natural antivirals against plant viruses, several reports concerning antiviral activity against plant virus infection have been recorded; for example, yeast mannans with antiviral activity against the tobacco mosaic virus infection in tobacco plants [136] , and lichenan ps from iceland moss which exhibited antiviral activity against the potato viruses [8] . jacquir immune defic syndr hum retrovirol the technical assistance of ms. brooke-turner is gratefully acknowledged. key: cord-013176-6ckuya1w authors: ninfali, paolino; antonelli, antonella; magnani, mauro; scarpa, emanuele salvatore title: antiviral properties of flavonoids and delivery strategies date: 2020-08-21 journal: nutrients doi: 10.3390/nu12092534 sha: doc_id: 13176 cord_uid: 6ckuya1w this review summarizes the latest advancements in phytochemicals as functional antiviral agents. we focused on flavonoids, like apigenin, vitexin, quercetin, rutin and naringenin, which have shown a wide range of biological effects including antiviral activities. the molecular mechanisms of their antiviral effects mainly consist in the inhibition of viral neuraminidase, proteases and dna/rna polymerases, as well as in the modification of various viral proteins. mixtures of different flavonoids or combination of flavonoids with antiviral synthetic drugs provide an enhancement of their antiviral effects. recent strategies in drug delivery significantly contribute to overcoming the low bioavailability of flavonoids. frequent viral infections worldwide have led to the need for new effective antiviral agents, which can be identified among the various phytochemicals. in this light, screening the antiviral activities of a cocktail of flavonoids would be advantageous in order to prevent viral infections and improve current antiviral therapies. in the past two decades, studies conducted in our laboratory focused on the antioxidants present in vegetable foods and on their capacity to reduce the adverse physiological effects of the oxygen free radicals [1, 2] . the research was also aimed at the technologies of food transformation in order to preserve, as much as possible, the antioxidants in the final products [3] . antioxidants are mainly represented in nature by the liposoluble vitamins e and a, β-carotene, hydro-soluble vitamin c and a wide range of amphipathic molecules, broadly termed phenolic compounds [1] . these compounds are divided into several sub-classes, including phenolic acids and analogues, stilbenes, flavonoids and their analogues. flavonoids possess important health protective effects, including anti-inflammatory, anticancer and antiviral properties [4] [5] [6] [7] [8] [9] [10] . there are in nature more than 6000 flavonoids, which have been structurally identified and divided in classes: flavones (e.g., apigenin), flavanols (e.g., quercetin), flavins (e.g., epigallocatechin-3-gallate), isoflavones (e.g., genistein) and anthocyanidins (e.g., cyanidin). flavonoids occur in their free or conjugated form or are often esterified with one or two sugars with o-glycosidic or c-glycosidic bonds [11] . in the past decade we purified and studied the biological effects of a group of the flavonoid c-glycosides derived from apigenin, namely vitexin, vitexin-2-o-rhamnoside and vitexin-2-o-xyloside ( figure 1 ). the interest in the antiviral activity of natural flavonoids has increased in the last decade because of the frequency of viral infections, particularly influenza infections, which affect several million patients annually [12] . while vaccination is the primary strategy for influenza prevention, there are scenarios for which vaccination is not possible and antiviral molecules represent an important sanitary presidium. synthetic antiviral drugs often show limited efficacy and serious adverse effects [13] , whereas herbal extracts, known for their antiviral properties with no or mild side effects, may be a viable alternative for treating various viral diseases [14] . viruses consist of nucleic acid (dna or rna) enclosed in a protein structure, called capsid, which can be surrounded by a lipid membrane named the envelope. the infective unit of the virus is called the virion and this parasite can replicate only inside host cells, hijacking the molecular machinery and controlling dna replication, rna transcription and the protein translation processes. viruses attack the host cells through adsorption to receptors specific for each type of target cells, penetrating through the cell membrane, then the genetic material of the virus is liberated to replicate its own genome, produce new viral proteins and obtain new virions [15] . in 2017, the antiviral effects of various phytochemicals were reviewed by kapoor et al. [15] , taking into consideration many categories of compounds, ranging from flavonoids to saponins and lignans. in the same year, another group published a review focused specifically on the antiviral effects of the six classes of flavonoids [16] . in 2020, an interesting review regarding the methods for delivery of phytochemicals to increase their bioavailability in human tissues has been published [17] . in this review, we first summarize flavonoids along with their class and plant sources, with particular attention to apigenin, vitexin and its derivatives (table 1) . we then discuss the antiviral action mechanisms of flavonoids, their combinations with conventional antiviral drugs in multitarget cocktails, and the delivery strategies used to increase their bioavailability and antiviral efficacy. the interest in the antiviral activity of natural flavonoids has increased in the last decade because of the frequency of viral infections, particularly influenza infections, which affect several million patients annually [12] . while vaccination is the primary strategy for influenza prevention, there are scenarios for which vaccination is not possible and antiviral molecules represent an important sanitary presidium. synthetic antiviral drugs often show limited efficacy and serious adverse effects [13] , whereas herbal extracts, known for their antiviral properties with no or mild side effects, may be a viable alternative for treating various viral diseases [14] . viruses consist of nucleic acid (dna or rna) enclosed in a protein structure, called capsid, which can be surrounded by a lipid membrane named the envelope. the infective unit of the virus is called the virion and this parasite can replicate only inside host cells, hijacking the molecular machinery and controlling dna replication, rna transcription and the protein translation processes. viruses attack the host cells through adsorption to receptors specific for each type of target cells, penetrating through the cell membrane, then the genetic material of the virus is liberated to replicate its own genome, produce new viral proteins and obtain new virions [15] . in 2017, the antiviral effects of various phytochemicals were reviewed by kapoor et al. [15] , taking into consideration many categories of compounds, ranging from flavonoids to saponins and lignans. in the same year, another group published a review focused specifically on the antiviral effects of the six classes of flavonoids [16] . in 2020, an interesting review regarding the methods for delivery of phytochemicals to increase their bioavailability in human tissues has been published [17] . in this review, we first summarize flavonoids along with their class and plant sources, with particular attention to apigenin, vitexin and its derivatives (table 1) . we then discuss the antiviral action mechanisms of flavonoids, their combinations with conventional antiviral drugs in multi-target cocktails, and the delivery strategies used to increase their bioavailability and antiviral efficacy. the most common flow chart for studies regarding the antiviral activity of phytochemicals is focused on the immediate testing of the whole natural extract, by dividing the polar from the non-polar constituents. after that, fractions with remarkable activity in in vitro antiviral assays, such as cytophatic effect, neutralization assay, hemagglutination, viral enzyme inhibition, or virion number reduction assay, are further fractionated through chromatographic techniques in order to purify the active phytochemicals. effective compounds are then used on virus-infected animals or in human clinical trials in order to assess their effective antiviral properties [15] . the complete procedure, when interfaced with chemical libraries, represents the basis for high throughput screening assays [15] . the parameter used for assessing antiviral efficiency of drugs and phytochemicals is represented by 50% inhibitory concentrations (ic 50 ) or by 50% effective concentration (ec 50 ). table 2 shows the main flavonoids studied for antiviral activity along with their investigated mechanisms of action. in the first section, we point out the studies focused on apigenin, vitexin and their derivatives, which were found active against many viruses like human hepatitis c virus (hcv), herpes simplex virus-1 (hsv-1), human hepatitis a and b viruses (hav; hbv), rhesus rotavirus (rrv) and influenza virus. the natural extract of eclipta alba (asteraceae) was shown to be able to inhibit the hcv replicase in a cell culture system, which resulted in reduced hcv rna titer and translation level of viral proteins [19] . through bioassay-based fractionations of the natural extract, the authors identified two flavonoid compounds: apigenin and luteolin, which, tested individually, exhibited a dose-dependent inhibition of hcv replicase in vitro [19] . quercetin, extracted from embelia ribes (mirsinaceae), exhibited antiviral effects against hcv, exerted through activity inhibition of the viral protease non-structural protein 3 (ns3), leading to a decrease in hcv replication [36] . furthermore, the flavanol quercetagetin was found to inhibit hcv rna-dependent rna polymerase (rdrp) through inhibition of rna binding to the viral polymerase, a mechanism associated with broad genotypic activity against several hcv strains and a high barrier to resistance mechanisms [39] . luteolin and quercetin showed anti-hcv effects in hepatoma huh-7 cells transfected with non-structural protein 5b (ns5b) cloned gene vector, that codifies for the ns5b polymerase of hcv virus [40] . naringenin and quercetin possess antiviral activity against hcv, but naringenin showed stronger inhibition of virion assembly, whereas quercetin inhibited viral translation by blocking non-structural protein 5a (ns5a) and internal ribosome entry site (ires)-mediated translation, as well as heat shock protein 70 (hsp70) induction [41] . bioinformatics tools were also used to study the interaction of various phytochemicals with viral proteins that possess pivotal roles in the production of new virions and in the infection of the host cells. this approach may be a useful premise for deeper investigation regarding flavonoids which have provided interesting evidence of interactions with viral proteins. for instance, naringenin, diosmetin, apigenin and luteolin were all able to bind to the ns5b protein of hcv with higher affinity when compared with the antiviral drug sofosbuvir, inhibiting the activity of this viral enzyme [25] . epigallocatechin-3-gallate (egcg), the principal tea derived catechin, efficiently inhibited cell culture-derived hbv entry into hepatocellular cell lines, independent of the hbv genotypes, through a mechanism that involves the clathrin-dependent endocytosis of the hbv receptor sodium taurocholate co-transporting polypeptide (ntcp) from the plasma membrane, followed by its protein degradation [26] . the extract obtained from erythrina speciosa (fabaceae) exerted antiviral effects against hav-h10 viruses mainly due to vitexin which, isolated from the extract, exhibited an antiviral activity against this virus with ec 50 = 41.6 ± 7.6 µm [42] . the authors showed that the flavone vitexin can interact with the binding pocket of hav 3c proteinase, inhibiting this enzyme [42] . hcv virions inhibition of virion assembly vitexin, extracted from the plant flos trollii, (caryophyllaceae), exerted its anti-h1n1 influenza virus effects through partially down-regulating toll-like receptor 3 (tlr3) and toll-like receptor 7 (tlr7) pathways and up-regulating toll-like receptor 4 (tlr4) molecular pathway [38] . tlrs are transmembrane glycoproteins, which are privileged targets of several viruses and can be activated by endogenous molecules in the context of inflammation. tlr activation produces pro-inflammatory cytokines through nuclear factor kappa-light-chain-enhancer of activated b cells (nf-kb) signaling pathway or through interferon regulatory factor 3 (irf3) and interferon regulatory factor 7 (irf7). some viruses enter the host cells by binding tlr3, but after their entrance the viruses are able to inhibit cytokine production, thus impairing the immune response. phytochemicals able to decrease the binding between tlrs and virus particles can slow the infective process. interestingly, virus infection can lead to an induction of the inflammation process, characterized by excessive production of nitric oxide (no), interleukin-1 (il-1), interleukin-6 (il-6) and tumor necrosis factor-α (tnf-α). it was shown that various flavonoids enhance the production of interferon-β (ifn-β) in order to counteract the viral infections [38] . baicalin, baicalein, wogonin, chrysin and oroxylin a, isolated from scutellaria baicalensis, showed anti-h1n1 activities, with ic 50 values of 7.4, 7.5, 2.1, 7.7 and 12.8 µm, respectively, and were all more potent than the conventional antiviral drug oseltamivir phosphate, which had an ic 50 of 45.6 µm [22] . these flavonoids increased the transcriptional activity of nuclear factor erythroid 2-related factor 2 (nrf2), the master regulator of the antioxidant responses, whose activation is related to the antiviral effects of scutellaria baicalensis [22] . the natural extract of tetrastigma hemsleyanum (vitaceae) contains many flavonoids, including vitexin, vitexin-2-o-rhamnoside, isorhamnetin, rutin, kaempferol, astragalin, quercitrin, quercetin and iso-quercetin, which were shown to be able to exert anti-influenza virus activity, with different efficiency, through the reduction of the number of plaques induced by the influenza virus in infected madin-darby canine kidney (mdck) cells [21] . similarly, the flavonoid quercetin-3-rhamnoside, extracted from houttuynia cordata (saururaceae), exerted anti-influenza a/ws/33 activity reducing virus-mediated cytopathic effects, directly interacting with virus particles [37] . furthermore, the same authors showed that quercetin-3-rhamnoside exerted anti-influenza virus activity in mice, when used at 6.25 mg/kg/day for six days after influenza virus infection [45] . flavonoids sanggenon o, egcg and chamaejasmin were all potentially able to inhibit dengue virus replication by blocking the asn-130 glycosylation site of the viral protein non structural protein 1 (ns1) [23] . baicalin, a flavonoid derived from scutellaria baicalensis (lamiaceae), exhibited viricidal activity against dengue virus-2 (denv-2) extracellular virions with ic 50 = 19.6 ± 0.2 µm, exerted an anti-adsorption effect with ic 50 = 40.5 ± 0.4 µm and also inhibited virus replication with ic 50 = 30.2 ± 0.2 µm [44] . studies of the antiviral effects of the flavonoids fisetin, quercetagetin, and pinocembrin showed that fisetin can inhibit the replication molecular machineries of dengue virus and enterovirus a71 [35] . furthermore, other antiviral mechanisms of the pinocembrin consist in targeting the molecular machinery used by the zika virus to replicate its own genome inside the host cells [33] . this flavanone acts on the post-entry processes of zika virus replication cycle through the inhibition of both viral rna production and synthesis of envelope proteins [33] . interestingly, the plant moringa oleifera lam (moringaceae) provides a rich and rare combination of several phytochemicals, including the flavonoids quercetin and kaempferol, and its leaves extract can be applied as a prophylactic or therapeutic anti-hsv-1 medicine [29] . the extract obtained from moringa oleifera lam remarkably reduced the plaque formation induced by wt hsv, thymidine kinase-deficient hsv and phosphonoacetate-resistant hsv strains [29] . furthermore, the extract obtained from erythrina speciosa possessed antiviral properties against the hsv-1 virus, mainly due to vitexin which exhibited an antiviral activity with ec 50 = 80.9 ± 6.2 µm, exerted through the interaction of this flavone with the binding pocket of hsv-1 thymidine kinase [42] . vitexin and luteolin from aspalathus linearis (fabaceae) showed antiviral activity against rrv with ic 50 of 129 µm and 116 µm , respectively; interestingly, apigenin-7-o-glucoside from melissa officinalis (labiateae) inhibited viral growth, with an ic 50 of 150 µm, through the reduction of the number of rrv-induced plaques in infected ma104 cells [20] . tangeretin and nobiletin, two polymethoxyflavones extracted from citrus reticulate "chachi", possess anti-rsv properties. tangeretin exhibited a dose-dependent inhibition of rsv-induced plaque formation on hep-2 cells, through inhibition of rsv entry into host cells and viral replication. furthermore, tangeretin decreased the levels of rsv phosphoprotein (p protein), which is associated with the viral genome to form the holo-nucleocapsid. the extent of the antiviral effect of this phytochemical was comparable to the conventional antiviral drug ribavirin [32] . the knowledge of the molecular mechanisms of virus infection and phytochemical antiviral actions is fundamental in planning an effective therapeutic approach. the main mechanisms involved in the antiviral effects of phytochemicals are focused on the targeting of viral enzyme activities. many natural molecules target the catalytic activity of the influenza virus neuraminidase, also called sialidase. this enzyme is a glycoside hydrolase that cleaves the glycosidic linkages of sialic acids ( figure 2 ). various phytochemicals inhibit the activity of viral sialidases, hampering the release of new virions from the infected cells and preventing new infections [47] . another enzyme with a pivotal role in influenza a virus infection is rdrp, which is composed of three subunits: polymerase acidic subunit (pa), protein binding 1 subunit (pb1) and protein binding 2 subunit (pb2). the enzyme synthesizes viral mrnas using short capped primers derived from host cellular mrnas, which are cut by the viral endonuclease. the n-terminal domain of the pa subunit contains a typical endonuclease active site and harbors the rna/dna endonuclease activity, which is essential for viral growth [48] . the knowledge of the molecular mechanisms of virus infection and phytochemical antiviral actions is fundamental in planning an effective therapeutic approach. the main mechanisms involved in the antiviral effects of phytochemicals are focused on the targeting of viral enzyme activities. many natural molecules target the catalytic activity of the influenza virus neuraminidase, also called sialidase. this enzyme is a glycoside hydrolase that cleaves the glycosidic linkages of sialic acids (figure 2 ). various phytochemicals inhibit the activity of viral sialidases, hampering the release of new virions from the infected cells and preventing new infections [47] . another enzyme with a pivotal role in influenza a virus infection is rdrp, which is composed of three subunits: polymerase acidic subunit (pa), protein binding 1 subunit (pb1) and protein binding 2 subunit (pb2). the enzyme synthesizes viral mrnas using short capped primers derived from host cellular mrnas, which are cut by the viral endonuclease. the n-terminal domain of the pa subunit contains a typical endonuclease active site and harbors the rna/dna endonuclease activity, which is essential for viral growth [48] . enzymes involved in the hcv virus replication, like the protease ns3 and the polymerase ns5b can also be efficiently inhibited or modulated by phytochemicals ( figure 3 ). ns3 is a hcv nonstructural protein, which acts as a serine protease. its n-terminal domain can interact with the viral non structural protein 2 (ns2), while the c-terminal domain acts both as helicase and nucleoside triphosphatase. enzymes involved in the hcv virus replication, like the protease ns3 and the polymerase ns5b can also be efficiently inhibited or modulated by phytochemicals ( figure 3 ). ns3 is a hcv nonstructural protein, which acts as a serine protease. its n-terminal domain can interact with the viral non structural protein 2 (ns2), while the c-terminal domain acts both as helicase and nucleoside triphosphatase. the ns5b protein is rdrp with a pivotal role in replicating hcv's viral rna by using the viral ssrna+ as a template to catalyze the polymerization of ribo-nucleoside triphosphates during replication of the viral genome. interestingly, quercetin, apigenin and luteolin effectively inhibit ns5b polymerase activity [33] . when phytochemicals have been combined among them or with synthetic antiviral drugs, synergistic therapeutic effects were often evidenced. overall, when synergy occurred, it was often justified by the fact that the different molecules target different steps in the the ns5b protein is rdrp with a pivotal role in replicating hcv's viral rna by using the viral ssrna+ as a template to catalyze the polymerization of ribo-nucleoside triphosphates during replication of the viral genome. interestingly, quercetin, apigenin and luteolin effectively inhibit ns5b polymerase activity [33] . when phytochemicals have been combined among them or with synthetic antiviral drugs, synergistic therapeutic effects were often evidenced. overall, when synergy occurred, it was often justified by the fact that the different molecules target different steps in the molecular mechanisms of viral infection, and the final antiviral effect results therefore potentiated. naringenin is a flavanone, which exhibits anti-hcv activity by blocking the assembly of hcv particles [41] . the phytochemical quercetin exerted anti-hcv activity by reducing internal ribosome entry site-(ires-)mediated translation and also inhibiting the viral non-structural protein ns5a as well as the protease ns3 [41] . when naringenin and quercetin were used together they suppressed hcv rna replication and inhibited viral replication to a higher extent when compared with the phytochemicals used individually, thus demonstrating a synergistic effect [41] . ladanein, a flavone isolated from marrubium peregrinum l. (lamiaceae), exploited antiviral effects through the inhibition of the post-attachment entry step of hcv virions, with an ic 50 of 2.5 µm. ladanein, in combination with cyclosporine, showed a remarkable synergistic antiviral effect against various hcv genotypes [30] . the natural extracts from nymphaea alba l. (nymphaeaceae), containing iso-quercetin, hyperoside, quercetin, reynoutrin, apigenin and isokaempferide, showed anti-hcv activity, suppressing hcv ns3 gene expression in the transfected huh-7 cell line and inhibiting the viral genotype 1a replication. furthermore, the combination of nymphaea alba l. extract with the conventional drug boceprevir displayed synergistic effects for inhibition of hcv replication in a docking bioinformatics model [28] . an antiviral role of phytochemicals was also linked to the receptors recognized by viruses for their endocytosis, such as the membrane receptor ntcp. this protein has a mass of 56 kda and is involved in the transport of bile salt molecules, steroid hormones, thyroid hormones and xenobiotics. ntcp is required for the entry in hepatocytes of both hbv and human hepatitis d virus (hdv). in fact, the virus-receptor interaction leads to the clathrin-dependent endocytosis of hbv virions, which can replicate inside the host cells [26] . egcg, used at the dose of 50 µm, induced clathrin-dependent endocytosis of ntcp from the plasma membrane, leading to its degradation and inhibiting the entry of hbv virus into immortalized human primary hepatocytes (figure 3 ). two hiv enzymes address pivotal roles in virus replication and virion production: hiv reverse transcriptase and the homodimer of hiv protease (figure 4 ). hiv reverse transcriptase is an rna-dependent dna polymerase (rddp) and builds ssdna based on an rna template in its polymerase active site; the enzyme also cleaves the original rna template into pieces through its nuclease active site and finally it polymerizes a second dna strand to form the final dsdna, which is integrated in the host cell genome. interestingly, it was shown that egcg suppressed hiv-1 infection in hela-cd4-ltr-β-gal cells, with a ec 50 of 1.6 µm, by acting as a non-nucleoside hiv reverse transcriptase inhibitor [43] . furthermore, it was demonstrated that the flavonoids myricetin-3-rhamnoside and myricetin-3-(6-rhamnosylgalactoside) possessed antiviral activity in vitro against hiv with ec 50 of 120 µm and 45 µm, respectively [31] . this antiviral effect was exerted through the inhibition of hiv reverse transcriptase with ic 50 of 10.6 µm for myricetin-3-rhamnoside and of 13.8 µm for myricetin-3-(6-rhamnosylgalactoside) [31] . hiv protease is a retroviral aspartyl protease, which cleaves newly synthesized viral polyproteins (namely gag-pol) at nine cleavage sites to create the mature protein components of the virion. mature hiv-1 protease exists as a 22 kda homodimer, each one containing an asp25 amino acid, which acts as the catalytic residues are able to hydrolyze peptide bonds on the gag-pol polyproteins into fully functional viral proteins, like reverse transcriptase and integrase. kehinde et al. (2019) [27] showed that the phytochemicals kaempferol-7-o-glucoside and egcg were able to interact with hiv-1 protease, showing pronounced structural evidence as potential hiv-1 protease inhibitors ( figure 4) . interestingly, phytochemicals can also be used to reduce the extrusion of antiviral drugs from infected cells. in fact, apigenin, fisetin and luteolin were able to slow down the elimination of the antiviral drugs atazanavir, lopinavir, darunavir and saquinavir, which target the viral protease of hiv-1 [27] . dependent dna polymerase (rddp) and builds ssdna based on an rna template in its polymerase active site; the enzyme also cleaves the original rna template into pieces through its nuclease active site and finally it polymerizes a second dna strand to form the final dsdna, which is integrated in the host cell genome. interestingly, it was shown that egcg suppressed hiv-1 infection in hela-cd4-ltr-β-gal cells, with a ec50 of 1.6 µm, by acting as a non-nucleoside hiv reverse transcriptase inhibitor [43] . furthermore, it was demonstrated that the flavonoids myricetin-3-rhamnoside and myricetin-3-(6-rhamnosylgalactoside) possessed antiviral activity in vitro against hiv with ec50 of 120 µm and 45 µm, respectively [31] . this antiviral effect was exerted through the inhibition of hiv reverse transcriptase with ic50 of 10.6 µm for myricetin-3-rhamnoside and of 13.8 µm for myricetin-3-(6-rhamnosylgalactoside) [31] . hiv protease is a retroviral aspartyl protease, which cleaves newly synthesized viral polyproteins (namely gag-pol) at nine cleavage sites to create the mature protein components of the antiviral activity of flavonoids may be also due to the modulation of host cell enzymes used by the virus to take advantage for infection, such as the enzymes with a pivotal role in the production of radical oxygen species (ros), utilized to increase the number of virions. regarding hsv-1, which persists in the host in sensory neurons in latency, the enzyme nicotinamide adenine dinucleotide phosphate (nadph) oxidase (nox) family is a useful source of ros, which can be used to reactivate the viral infection under oxidative stress conditions [52, 53] . interestingly, delphinidin-3-rutinoside obtained from extracts of solanum melongena l. (solanaceae), inhibited hsv-1 replication through the reduction of nox4 protein levels, when added for 24 h after viral adsorption on vero cells [24] . the extract obtained from veronica persica poir (plantaginaceae) possessed a dose-dependent inhibitory activity against the herpes simplex virus strains hsv-1 and hsv-2 and a prominent synergistic activity in combination with acyclovir in anti-hsv therapy, exerted through a reduction of the percentage of plaque numbers of both hsv-1 and hsv-2 in the infected cero cells [54] . the natural extract of disticella elongata (bignoniaceae) exhibited antiviral effects against denv-2 virus and this effect was mainly due to pectolinarin and acacetin-7-o-rutinoside [18] . when the two flavonoids pectolinarin and acacetin-7-o-rutinoside were used in combination, the antiviral effect was eight times more potent against denv-2 virus (with ec 50 = 18.3 ± 2.6 µm) than the flavonoid pectolinarin used alone (with ec 50 = 138.8 ± 6.1 µm). the selectivity index of the combination (si = 45) was remarkably higher than the si of the isolated pectolinarin (si = 4.6), indicating that the phytochemical mixture specifically inhibited viral growth, with negligible effects on the vitality of the cells infected by denv-2 virus. the ethanol extract obtained from the leaves of disticella elongata showed antioxidant activities; therefore, it could detoxify cell damaging free radicals present in denv-2 viral infections [18] . the low water solubility and low bioavailability of natural flavonoids represent the major limit for their use in the nutraceutical sector. many delivery strategies have been used by researchers for increasing flavonoid bioavailability following oral consumption [16] , including: micelles, nanoparticles, microspheres, crystals, dendrimers, the self-micro-emulsifying drug delivery system (smdds) and the self-nanoemulsifying drug delivery systems (snedds), as recently reviewed [17, 55] . for instance, it was shown that the catechin and egcg-loaded chitosan nanoparticles led to a higher rate of intestinal absorption of the two phytochemicals [56] . interestingly, in chitosan particles the flavonoids maintain their antioxidant activity and can exploit their antioxidant effects in the blood stream [57] . the loading of myricetin into a cationic polymeric nanoparticle carrier with a cationic corona and hydrophobic core was investigated in order to improve the clinical relevance of this natural flavonoid by increasing its solubility [58] . smdds has been used to overcome the problem of low bioavailability of hydrophobic molecules as, in the intestinal lumen, the oil-in-water microemulsions containing phytochemicals may be efficiently formed with a consequent increase of the intestinal absorption of the flavonoid [59] . interestingly, puerarin, an isoflavone isolated from the root of pueraria lobata, exhibited 2.6 fold higher bioavailability when prepared using the smdds technique [34] . furthermore, the synthesis of silver nanoparticles linked with phytochemicals and their use for antimicrobial and antiviral treatments have been described, highlighting the various molecular mechanisms that lead to the phytochemical-mediated inhibition of viral replication [60] . poly (d,l-lactide) (pla) nanoparticles and polymeric micelles contributed to a more sustainable and efficient release of flavonoids characterized by a poor bioavailability, like quercetin and apigenin [61, 62] . quercetin was successfully encapsulated on the most uniformly distributed type of pla-4 nanoparticle, synthesized using lonicera japonica leaf extract, showing that these nanoparticles allowed a slow release of quercetin [63] . this nanoparticle approach paves the way for encapsulating drugs, small molecules, nutraceuticals and other bioactive ingredients to obtain safer cellular uptake, improved biodistribution, specific targeted delivery and enhancement of the therapeutic antiviral efficacy of encapsulated drugs and phytochemicals [64] . the increase in antiviral efficacy and bioavailability of flavonoids may be attained through their encapsulation into red blood cells (rbcs), as has occurred for other type of antiviral drugs and molecules, such as fludarabine (figure 4 ) [65] , vincristine and vinblastine [66, 67] . the idea of using rbcs as delivery system for flavonoids takes its advantage from the favorable characteristics of these cells. they have a long life-span of about 120 days and have a widespread circulation throughout the body, and hence can be used as drug reservoirs, enabling them to facilitate sustained drug release. moreover, rbcs protect encapsulated drugs and molecules from degradation; they are completely biodegradable and show no or only minor immunogenic responses. interestingly, the rbcs were used to determine cellular antioxidant activity of some flavonoids, specifically vitexin, vitexin-2-o-xyloside and vitexin-2-o-rhamnoside, with the aim of predicting their bioavailability [68] . moreover, it was demonstrated that flavonoids could have beneficial effects in preventing oxidative damage of erythrocyte membrane [69, 70] . some authors have also evidenced the possibility that human rbcs play a pivotal role in the distribution and bioavailability of circulating flavonoids such as quercetin [71] . furthermore, it was shown that drug-loaded rbcs can be modified in order to increase their macrophage-mediated phagocytosis by inducing band 3 clustering and opsonization through the complementary and autologous iggs [72] . in future perspective, this approach could be considered in order to possibly improve the antiviral activity of some flavonoids, like baicalin, that was able, like fludarabine [65] , to act against hiv-1 chronic infection of human monocytes and macrophages, inhibiting the fusion of hiv virus envelope proteins with these cells [73] . although polymeric nanoparticles, liposomes, dendrimers, micelles and inorganic nanoparticles have been widely accepted as drug delivery systems, they show toxicity and a short lifetime, thus making them relatively disadvantageous when compared with natural cell carriers, such as rbcs. for this reason, some authors in recent years have tried to mimic the erythrocyte cell membrane to produce biocompatible nanocarriers in order to decrease their toxicity and to prolong their survival in blood circulation [74] [75] [76] . rbcs, which are biodegradable and non-immunogenic, can be used as a valuable carrier system with a lifespan that is remarkably prolonged and controllable when compared to synthetic carriers. several approaches have been developed to load peptides, drugs and molecules into rbcs or to attach these agents onto rbcs' outer membrane surface by either chemical or physical methods [77] and the possibility of loading drugs into autologous rbcs prior to their transfusion into patients has been studied in small animal models and primates, as well as in clinical studies of human patients [78] [79] [80] [81] . the topic of phytochemical encapsulation in rbcs remains open for further studies, but we believe that flavonoid derivatives and nanoparticles able to bind flavonoids could be successfully considered for this application in the near future. diet and life-style play important roles in the defense against the attacks of viruses. the relationship between diet and the immune system involves the microbiota, i.e., the ecological community of commensals and potentially pathogenic microbes and symbionts that live in the gut [82] . the diet modulates the microbiota composition, leading to an increase or a decrease in immune defenses [82] . the mediterranean diet (and in general diets rich in fruits, vegetables and herbs) maintains gut microbiota homeostasis and provides protection against microbes and viruses [83] . the cross-talk between microbiota and immunity is supported by the aryl hydrocarbon receptor (ahr), which is ubiquitous, but mainly present in the cytoplasm of immune cells [84] . it was demonstrated that ahr binds different ligands, namely metabolites, pollutants and pathogenic molecules, and after this interaction it translocates into the nucleus, where it induces specific transcription programs and modulates the defensive functions of both t and b cells, dendritic cells and monocytes [84] . interestingly, it was shown that flavonoids can bind ahr [84] . on this basis, people eating vegetables, all of which contain flavonoids to a different extent, would strengthen their immune system [83] . this strengthening is a general effect that occurs with many nutrients, but there are more specific antiviral effects attributable to the flavonoids treated in this review. flavonoids, like apigenin, vitexin, quercetin, rutin and naringenin, show a wide range of antiviral effects (table 2) , because they are able to target different pathways of viral infections. it is therefore possible to increase the chances of blocking viral replication using mixtures of flavonoids with synergistic antiviral effects, because of the pleiotropic effects of their combination. an important question that arises is focused on the reasonable concentration range of flavonoids that should be used for an effective antiviral therapy, which is hard to be reached by diet alone. recent experiments performed in in vivo studies demonstrated the protective efficacy of various flavonoids, tested in the range 10-50 mg/kg body weight per day, in newborn mice challenged with a lethal dose of the enterovirus 71 [85] . interestingly, apigenin (50 mg/kg), luteolin (10 mg/kg) and quercetin (10 mg/kg) conferred survival protection of 88.9%, 91.7% and 50.1%, respectively, from the lethal enterovirus 71 infection; moreover, isorhamnetin provided the highest survival protection of 100% at a dose of 10 mg/kg. the authors hypothesized that the differences in concentrations are due to different times of absorption and renal clearance of these flavonoids [85] . the flavanol isorhamnetin was studied also by dayem et al. [86] , who showed that oral administration of this flavonoid at 1 mg/kg/day for five days in mice infected with the influenza a virus significantly decreased lung virus titer by two-fold, increased the survival rate (which ranged from 70% to 80%) and decreased mice body weight loss by 25%. these authors hypothesized that the methyl group of the b ring of isorhamnetin may contribute to its strong antiviral potency against influenza a virus [86] . guo et al. [87] focused their in vivo studies on the flavone wogonin, showing that, in human hbv-transgenic mice, this flavonoid administered once a day at 7, 14 and 28 mg/kg reduced plasma hbsag level and immunohistological staining of the liver confirming the hbsag reduction exerted by wogonin [87] . the potentiality of flavonoid bioactivity in vivo depends on the extent of their absorption after ingestion and their ability for distribution in various target tissues. in this light, liu et al. [88] developed a quercetin-loaded cationic nanostructure lipid carrier (q-cnlc), which increased the in vivo bioavailability of this flavonoid. this quercetin-nanostructure complex benefits from its strong interactions with negatively charged intestinal mucosa, which could increase its residence in the gastrointestinal tract. moreover, the authors showed an entrapment efficiency of quercetin of 89.3% and a slower release of this flavonoid from the q-clnc, when compared with the release profile of a simple quercetin solution, indicating that q-clnc exhibited a sustained and controlled release of this flavanol, in order to maintain its effective therapeutic concentration [88] . in addition, the same authors performed in vivo tissue distribution studies in c57bl/6j mice, comparing treatment with 25 mg/kg of orally administered quercetin solution with the administration of 25 mg/kg of q-cnlc, showing that the relative quercetin uptake from q-cnlc was 1.57 fold higher in lungs, 1.51 fold higher in liver and 1.68 fold higher in kidneys. on the contrary, the relative quercetin uptake from q-cnlc was lower in spleen, heart and brain, when compared with the quercetin solution [88] . these results indicate that the most suitable delivery strategy should be chosen in order to target a specific organ with a particular flavonoid-nanostructure complex for future clinical applications. furthermore, the safety of the used phytochemical should also be considered, as has already been done for hydroxytyrosol, which is quickly absorbed and eliminated by the kidneys in either free or conjugated forms. hydroxytyrosol has been considered safe at 50 mg/kg/day by the european food safety authority (efsa) panel [89] . in this light, we think that, for a 70 kg person, a flavonoid range between 0.5-3.0 g/day should be proposed. these values are close to the daily polyphenol intake in humans, calculated in various diet surveys [90] , such as the supplementation en vitamines et mineraux antioxydants (su.vi.max) study, which ranked the polyphenol intake at 1.19 ± 0.51 g/day [91] . accordingly, in another dietary intervention trial aimed at improving cognition in older adults, a total of 1.04 g/day of flavonoids was applied [92] . indeed, based on these results, we think that 0.5-3.0 g/day of flavonoids could be a reasonable concentration range in order to start preliminary experiments, focused on assessing the in vivo antiviral effects of flavonoids. concerning the combination of flavonoids in an antiviral cocktail, each phytochemical may be used initially at a concentration of about 0.5 g/day with the aim of reaching an intake of 3 g/day of antiviral flavonoids. in the case of antiviral synergistic effects [5, 6] or increase of the absorption of one specific flavonoid exerted by other phytochemicals [93] , the individual flavonoid concentrations can be modulated, according to the extent of the effect. it should also be emphasized that a significant antiviral effect is linked to the type of flavonoid mixture, the delivery system used, the pharmacokinetic pattern, the number of targets involved and the number of required daily doses. once these aspects have been defined, the more suitable regimen of administration consists of starting with the lowest effective concentration for a fixed time and proceeding with increasing doses of the antiviral flavonoids. monitoring the markers of antiviral efficacy and any side effects should also be considered in order to evaluate the risks-benefits pattern. overall, our review shows that many flavonoids exhibit antiviral activity and could offer a promising alternative for prevention of and therapy for viral infections. flavonoids are present in many vegetables and the first protection for the immune system resides in the ability to seek foods rich in bioactive nutrients. education programs for a healthy diet should be implemented during the outbreaks of viral infections [94] . in fact, a diet rich in vegetables activates the ahr in the gut for maintenance of microbiota homeostasis, which in turn regulates the immune system. in the critical periods of viral infections, oral dietary supplementation with nutraceutical preparations based on combinations of flavonoids can be useful in order to inhibit different steps of the viral infective cycle. molecular mechanisms underlying the antiviral effects of flavonoids, herein described, mainly focus on the inhibition of viral enzyme activities: neuraminidases, dna/rna polymerases and proteases. therefore, a cocktail of flavonoids, selected for their efficacy in the inhibition of different viral enzymes, could be associated with elevated immune response and offer a promising option for antiviral therapies. this option acquires great importance considering that the viral genome frequently mutates, due to the lack of proof-reading activity of most of the viral polymerases. these mutations could hamper the efficacy of antiviral synthetic drugs. on the contrary, antiviral flavonoids, as well as the combination of synthetic antiviral drugs with flavonoids, would enhance therapeutic strategies by targeting the multiple signaling pathways involved in the viral infections [95] . the active concentration of the flavonoids should be investigated, considering the pharmacokinetic studies available in the literature and the synergistic effects of the specific flavonoid combinations [15] [16] [17] . the scarce intestinal absorption and bioavailability of flavonoids, when given through food or in pills, may be enhanced by the use of new drug delivery strategies [96] . in fact, since flavonoids have some drawbacks after oral administration such as low stability, bioavailability and bio-efficacy, researchers are developing biocompatible nanomaterial synthesis as novel delivery systems (including nanospheres, nano-capsules, micro and nano-emulsions, micelles, solid lipid nanoparticles and capsules), for overcoming the delivery challenges of flavonoids in the biomedical sector. phytochemical-nanomaterial complexes can represent innovative drug delivery strategies (alongside those already known) for new antiviral therapies against the seven baltimore virus classes [97] . interestingly, three patents regarding the antiviral effects of flavonoids (us 7,998,937; ep1245230; us 6,399,654) have been already assigned to the korea research institute of bioscience and biotechnology and advanced life sciences inc. [35] . however, an important step that must be achieved is to obtain the authorization of novel food including flavonoids with antiviral properties, following regulation eu 2015/2283 [98] . nowadays, this authorization has been given only to hydroxytyrosol [89] and few other nutrients. if the antiviral efficacy and safety of flavonoids and their mixtures can be clearly demonstrated in vivo, it would be possible to obtain european food safety authority (efsa) authorization of novel foods, in order to provide new natural tools for preventing and facing outbreaks of viral infections. indeed, when flavonoids are administered through nano-sized delivery systems, they show increased stability and bioavailability with an enhanced and prolonged activity. however, the in vivo behavior and the antiviral actions of these nano-delivery systems are still under experimental evaluation. interferon regulatory factor 3 irf7 interferon polyphenols and antioxidant capacity of vegetables under fresh and frozen conditions antioxidant capacity of extra-virgin olive oils antioxidant capacity of vegetables, spices and dressings relevant to nutrition effect of flavonoids on human health: old subjects but new challenges vitexin 2-o-xyloside, raphasatin and (-) eepigallocatechin-3-gallate synergistically affect cell growth and apoptosis of colon cancer cells betalains increase vitexin-2-o-xyloside cytotoxicity in caco-2 cancer cells antiproliferative activity of vitexin-2-o-xyloside and avenanthramides on caco-2 and hepg2 cancer cells occurs through apoptosis induction and reduction of pro-survival mechanisms natural and synthetic avenathramides activate caspases 2,8,3 and downregulate htert, mdr1 and cox-2 genes in caco-2 and hep3b cancer cells a combination of moringin and avenanthramide 2f inhibits the proliferation of hep3b liver cancer cells inducing intrinsic and extrinsic apoptosis flavonoids from beta vulgaris cicla and betalains from beta vulgais rubra: antioxidant, anticancer, antiinflammatory activities-a review characterization and biological activity of the main flaonoids from swiss chard (beta vulgaris subspecies cycla) oseltamivir resistance-disabling our influenza defenses twenty years of research into medicinal plants: results and perspectives combination of western medicine and chinese traditional patent medicine in treating a family case of covid-19 in wuhan. front antiviral phytochemicals: an overview flavonoids: promising natural compounds against viral infections antiviral effects of phytochemicals from medicinal plants: applications and drug delivery strategies antiviral activity of disticella elongata (vahl) urb. 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french adults enhancing dentate gyrus function with dietary flavanols improves cognition in older adults enhancement of flavonoid ability to cross the blood-brain barrier of rats by co-administration with α-tocopherol the food systems in the era of the coronavirus (covid-19) pandemic crisis. foods viral mutation rates flavonoids loaded in nanocarriers: an opportunity to increase oral bioavailability and bioefficacy nanomaterials designed for antiviral drug delivery transport across biological barriers of the european parliament and of the council and repealing regulation (ec) no 258/97 of the european parliament and of the council and commission regulation (ec) no 1852 this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license the authors want to thank university of urbino carlo bo for financial support. the authors declare no conflict of interest. the funders had no role in the writing of the manuscript or in the decision to publish this manuscript. key: cord-000445-2x7dfl1q authors: paliwal, sarvesh k.; verma, ankita narayan; paliwal, shailendra title: neglected disease – african sleeping sickness: recent synthetic and modeling advances date: 2011-05-10 journal: sci pharm doi: 10.3797/scipharm.1012-08 sha: doc_id: 445 cord_uid: 2x7dfl1q human african trypanosomiasis (hat) also called sleeping sickness is caused by subspecies of the parasitic hemoflagellate trypanosoma brucei that mostly occurs in sub-saharan africa. the current chemotherapy of the human trypanosomiases relies on only six drugs, five of which have been developed more than 30 years ago, have undesirable toxic side effects and most of them show drug-resistance. though development of new anti-trypanosomal drugs seems to be a priority area research in this area has lagged far behind. the given review mainly focus upon the recent synthetic and computer based approaches made by various research groups for the development of newer anti-trypanosomal analogues which may have improved efficacy and oral bioavailability than the present ones. the given paper also attempts to investigate the relationship between the various physiochemical parameters and anti-trypanosomal activity that may be helpful in development of potent anti-trypanosomal agents against sleeping sickness. african sleeping sickness remains one of the most neglected life threatening diseases that have been left untreated till date. two forms of human african trypanosomiasis (hat) have been identified that are parasite dependent. the first one trypanosoma brucei gambiense (t. b. gambiense) causes a human chronic infection, endemic in western and central africa while the other trypanosoma brucei rhodesiense (t. b. rhodesiense) has a vast animal reservoir and causes acute illness in people in eastern and southern african countries. hat has high occurance in the remote rural areas, where the surveillance is weak or nonexistent, with 50 to 70 thousand estimated cases. according to world health organization (who) estimation there are half-million cases of hat or "sleeping sickness" resulting from infections with t. brucei rhodesiense and t. brucei gambiense. who has attributed 50.000 deaths annually to the disease [1] . by more recent estimates, up to 25.000 new cases occur per year, and 50 million people are at risk [2, 3] . out of six clinically approved drugs for the treatment of hat, five (suramin, pentamidine, melarsoprol, eflornithine and nifurtimox) have had been discovered more than 30 years ago. because suramin and pentamidine are ionized at physiological ph, they are unable to cross the blood brain barrier in therapeutic concentrations and are thus used for the treatment of hemolymphatic early stage hat, caused by t. b. rhodesiense and t. b. gambiense infections, respectively. the treatment of the second or neurological stage, when the parasites invade the central nervous system (cns), relies on the organoarsenical drug melarsoprol and the more recently registered eflornithine. the latter is ineffective against t. b. rhodesiense sleeping sickness and is used primarily to control cns-involved hat caused by t. b. gambiense. all the existing anti-trypanosomal therapies suffer from unacceptable toxicity, poor efficacy, difficulties of administration, and increasing treatment failures due to the development of parasite resistance [4] [5] [6] [7] [8] [9] . in the last couple of decades, no new drug has been developed for treatment of early-stage hat, and only one drug has been developed for late-stage hat [1, 3, 5] . the need is great for new orally active drugs for the control and eradication of this disease. novel medicines are typically developed using a trial-and-error approach, which is timeconsuming and costly but yet has the potential to yield new drugs. the application of computer-assisted drug design (cadd) methodologies to this problem has the potential to greatly decrease the time and effort required to discover new medicines or improve current ones in term of their efficacy. this review focuses on the synthetic and computer-assisted drug design (cadd) approaches made by various research groups for the development of newer antitrypanosomal agents having improved efficacy and oral bioavailability. the current research also endeavors [10] to investigate the relationship between the various physiochemical parameters and anti-trypanosomal activity that may be helpful in development of potent anti-trypanosomal agents against sleeping sickness. safe, effective and affordable orally active therapies for trypanosomiasis capable of overcoming resistance are required, so the identification of new anti-trypanosomal drug candidates is an urgent priority. compared to the last 15 years there has been a revival of drug research and development regarding neglected parasitic diseases, and a number of drug development projects are currently ongoing [11] . in view of this, the researchers have endeavored to compile in the present section of the review, diverse series of compounds that have been recently synthesized by various research groups targeting dna minor groove and many other new targets. based on the mechanism of action this section has been divided into two sub-sections. the first sub-section includes the series of compounds acting as dna minor groove binders while in the second sub-section are included all the other anti-trypanosomal compounds and their respective targets. also are described herein prodrug approaches to provide oral bioavailability for the dication class. the wide range of antifungal and antiparasitic activities related to aromatic diamidines and its excellent results in preclinical and clinical phase of drug development has made aromatic diamidines an interesting class for the development of newer anti-trypanosomal drug therapy. the aromatic diamidines i.e. pentamidine ( figure 1) show their anti-parasitic action by binding strongly to at-rich sequences in the minor groove of dna. therefore dna minor groove has evolved as a productive target for designing new ant-parasitic drugs. in order to design newer analogues belonging to diamidine series, studies of the dna complexes with diamidine compounds have been conducted and a number of diamidines have been crystallized with the dna duplex d(cgcgaattcgcg)2 which provide valuable models for drug development in the diamidine series. structures of dna complexes of furamidine, berenil, and pentamidine, for example, reveal that they all bind in the dna minor groove at the central aatt sequence. these drugs penetrate deeply into the groove and fit snugly between the walls of the groove. their amidines form h-bonds with thymine-o2 and/or adenine-n3 acceptor groups on the edges of the bases at the floor of the groove. the amino group of g protrudes into the minor groove and prevents the compounds from assuming their preferred orientation deep in the minor groove. this binding to dna eventually leads to inhibition of one or more of the several dna-dependent enzymes (e.g., topoisomerases and nucleases) or direct inhibition of transcription. for more than 50 years aromatic diamidines and related dicationic molecules have been extensively used but so far only pentamidine [12] [13] [14] [15] has been widely employed as a drug in humans despite several adverse effects, such as hypotension, abdominal pain, vertigo, hypersalivation, hypoglycemia, nausea, and mild nephrotoxocity [5] [6] [7] [8] . being a highly flexible molecule that can assume an array of linked conformations related through torsional rotation, changes can be made in the nucleus to produce improved analogous against hat. in line to this with an aim to increase the efficacy and decrease the side effect related to pentamidine various research groups have made several changes in the pentamidine molecule [16] [17] [18] [19] [20] [21] [22] [23] large numbers of structurally related congeners of pentamidine were synthesized by tidwell rr et al [24] by introducing substitutions on the cationic groups, changing the position of dications from 4,4' to 3,3' position, changing the length of the aliphatic chain between the two aromatic rings, adding substituent on the aromatic rings at 2,2' and 3,3' position and replacing oxygen atoms in the alkyl linker with isosteric sulfur or nitrogen atoms (figure 2a-g) . on comparing the activities of the synthesized compounds with pentamidine and melarsoprol, it was found that few compounds showed activity in the range or better than that of pentamidine and/or melarsoprol. the unsubstituted diamidine compound 64 ( figure 3a ) with secondary amino group in place of oxygen atom exhibited subnanomolar activity (<0.001 µm) against t. b. rhodesiense and was nearly twice as selective against the pathogen as pentamidine. at the same time the diimidazoline compound 66 (figure 3b ) exhibited the second highest anti-trypanosomal activity in the series with the ic 50 value of 0.001 µm and also had the highest parasite selectivity (si t = 34500), being 63 times more selective against t. b. rhodesiense than pentamidine. the replacement of oxygen atom with sulphur atom as in compound 62 ( figure 3c ) also generated active congeners having ic 50 (0.005 µm) value better than that of pentamidine (0.007 µm). the compounds 20-31 ( figure 2c ) in which the cationic groups were present in the 3,3′-position of the aromatic rings and the length of the carbon linker was varied from 3-6 exhibited lower anti-trypanosomal activity compared to pentamidine whereas among the compounds 12-19 ( figure 2b ) of the series, in which the amidine groups were present at 4,4' position and the length of aliphatic chain was varied from three carbon atoms to six carbon atoms, compound 12 ( figure 3d , ic 50 =0.007 µm) with three methylene linker between the aromatic rings had same in vitro activity as that of pentamidine (0.007 µm). further introduction of 2,2′-dichloro substituent in compound 12 improved the antitrypanosomal properties as evident from the in vitro activity of compound 32 (figure 3e , ic 50 =0.004 µm). these compounds having excellent in vitro activity were evaluated in vivo in the stib900 mouse model of african trypanosomiasis. the screening was conducted using intraperitoneal dosing at 20 mg/kg daily for four days. the compounds 12, 62 and 64 showed very poor in vivo activity, whereas compound 32 and 66 exhibited excellent in vivo efficacies in the acute mouse model of trypanosomiasis, providing cures of all infected animals. thus, because of high selectivity, excellent in vitro and in vivo activity compounds 66 and 32 can serve as a novel lead for further pre-clinical and clinical trials, but its cytotoxcity profile needs to be monitored during its evaluation. also compound 64 which showed excellent in vitro, in vivo activity and high selectivity index against the t. b. rhodesiense merits further sar optimization in order to synthesized newer lead compounds with reduced cytotoxicity compared to pentamidine. pentamidine analogues with activity better than that of melarsoprol and/or pentamidine increased efficacies of pyridyl analogues of 2,5-bis(4-amidinophenoxy)furan (furamidine) [25] [26] [27] encouraged tidwell rr et al [28] to synthesize pentamidine analogues in which the phenyl rings of pentamidine were replaced with pyridyl fragments. this replacement resulted in series of 18 compounds (figure 4a ), most of which had lower cytotoxicity than pentamidine. sar study pointed out that the antiprotozoal properties of these compounds depended on the placement of cationic moieties on the pyridine rings as well as the nature of substituents on the amidine groups. the n-substituted congeners were lesser cytotoxic than the unsubstituted diamidines whereas the n-alkylation of cationic fragments reduces the activity of compounds against t. brucei rhodesiense compared to pentamidine. a same trend was observed in pentamidine analogues series. the 2, 6-substituted dications (compounds 11-13, figure 4a ) and 2,4-substituted dications (compounds 14-18, figure 4a ) displayed lower potencies against t. brucei rhodesiense than the corresponding 2,5-substituted isomers (compounds 1-10, figure 4a), while among the 2, 5-substituted dications, the compounds possessing cationic substituents adjacent to nitrogen atoms in pyridine rings displayed superior activities against parasites compared to pentamidine as evident from compound 6 (figure 4b) which showed promising anti-trypanosomal activity (0.001µm) and lower cytotoxicity (4.90µm) than pentamidine and melarsoprol, but had poor in vivo activity giving only 1/4 cures in the stib900 mouse model. however diamidoxime compound 9 (figure 4c ), an oral prodrug of diamidine compound 6 ( figure 4b ), exhibited excellent in vivo activity curing four out of four animals upon oral administration in stib900 mouse model. although compound 9 did not provide cure in the cns mouse model of infection but its bbb permeability could potentially be improved by developing prodrug using lipophillic substitutions in place of hydrophilic substitution as used in compound 9. this could provide higher concentration of compound 6 in cns. thus excellent in vitro activity of diamidine 6 and high in vivo efficacy of its prodrug diamidoxime 9 warrant further investigation of these dications as potential antitrypanosomal drug candidates with improved oral efficacies. the structure activity relationship of the two series indicates that in both the cases the unsubstituted diamidines were more active than the n-substituted diamidines. the replacement of oxygen atoms in alkyl chain with secondary amino group improves the activity against t. b. rhodesiense of pentamidine analogues while in case of pyridyl analogue the compounds with oxygen atoms in the alkyl chain have been the active one. the most potent compound of these two series are compound 6 ( figure 4b ) and compound 66 (figure 3b ), which have excellent in vitro activity (0.001µm) better than pentamidine and melarsoprol and also have high selective against the t. b. rhodesiense parasite as evident from their selectivity index (si of compound 6 = 4900 and compound 66 = 34500 µm). initially it has been believed that the oxygen atom in the aliphatic linker and the amidine groups are important for anti-trypanosomal activity of pentamidine as these groups were part of recognition motif for p2 amino purine transporter in trypanosoma species. thus the activity of compound 6 can be explained on this basis, but in case of compound 66 the amidine groups have been replaced by imidazoline and the oxygen atom has been replaced by secondary amino groups. despite these replacements, the compound has shown excellent in vitro and in vivo activity. thus this is in accordance to recently reported work [29] according to which there is no direct connection between the affinity for p2 carrier and anti-trypanosomal activity. in view of this, these two compounds can serve as a lead structure for the development of newer analogues of pentamidine with reduced side effect and improved pharmacokinetic profile. in the early 1970s dann o et al [30] [31] [32] fig. 6 . structure of two phenylbenzofuran dications with promising anti-trypanosomal activity tidwell rr et al found that the in vitro anti-trypanosomal activities of bisbenzofuran derivatives against trypanosoma brucei rhodesiense, and cytotoxicity against mammalian cells depended on the position and the type of cationic substituents as well as the length of the carbon linker between aromatic moieties. as observed in most of the dicationic molecules, the n-substituted congeners were lesser cytotoxic than the unsubstituted diamidines whereas the n-alkylation of cationic fragments reduced the activity of compounds against t. brucei rhodesiense compared to pentamidine. at same time the 5-substituted bisbenzofurans were generally less cytotoxic than compounds bearing substituents in the 4-or 6-positions where as the 4-substituted bisbenzofurans were significantly less active against t. b. rhodesiense than corresponding 5-and 6-substituted isomers. the in vitro activity of the bisbenzofuran series was not so promising and only lead compound 8, (figure 5b ) exhibited in vitro anti-trypanosomal activity (0.008 µm) comparable to that of pentamidine and melarsoprol. however some compounds from tidwell series (figure 7b ) showed reduced cytotoxicity profile compared to pentamidine (for example compound 43 has cytotoxicity of 1.85 µm), but had very poor selectivity profile. thus was proved that the selectivity of bisbenzofurans against t. b. rhodesiense decreases as number of methylene groups in the alkyl bridge increases. however, how the substitution on the amidine groups affects the anti-trypanosomal properties of bisbenzofurans has not been explained. thus in light of their reduced cytotoxicity compared to pentamidine these molecules require further investigation to study the influence of the type of cationic substituents and the distance between aromatic moieties on uptake and intracellular distribution of dicationic bisbenzofurans in order to understand better the mode of action and thus improve the efficacy of aromatic diamidines. thus promising in vitro, anti-trypanosomal activity, excellent potency in the acute mouse model of trypanosomiasis and the reduced cytotoxicity (1.9 µm) of compound 1 compared to pentamidine warrants further pre-clinical and clinical trials of this molecule. while compound 32 and 20 can serve as lead compounds for further sar optimization to derive congener with enhanced activity and lesser cytotoxicity. to combine the rigidity of 2-phenylbenzofurans with the flexibility of pentamidine congeners, tidwell rr et al [35] incorporated the benzofuran ring into molecules of pentamidine-related analogues. a series of 48 pentamidine congeners containing benzofuran fragments (figure 10a , b) were synthesized and tested in vitro against t. b. rhodesiense. most of the compounds in the series showed cytotoxicity less than that of pentamidine, but had lesser potency and selectivity index as compared to pentamidine. the properties and cytotoxicities of these dications depended on the nature of the cationic substituents, the placement of the benzofuran motif, and the length of the carbon linker. within the series cytotoxicity of the compounds decreased with the substitution on cationic groups and increased with the elongation of the carbon linker. dications with the benzofuran motif in the 4'-position (compounds 25-48, figure 10b ) and connected by the propylene linker are the most potent and more selective against t. b. rhodesiense among the series. thus on the basis of sar study further improvements can be made in order to produce newer anti-trypanosomal agents with improved pharmacological activity. the sar of the three series clearly indicates that the nature of cationic substituents and their position is important in deciding the anti-trypanosomal activity of benzofuran derivatives. the introduction of phenoxy fragment into a benzofuran structural motif may result into retention of affinity for the aminopurine p2 transporter, which could be the reason for anti-trypanospomal activity of benzofuran derivatives. however the precise mechanism by which these compounds show their anti-trypanosomal activity in not known. among the three series the 2-phenylbenzofuran derivatives are attractive molecules because of their high activity, low cytotoxicity and high selectivity against the hat parasite. the introduction of phenoxy fragment into the aromatic ring protects the phenylbenzofuran dervatives from metabolic deactivation. this structural modification retains affinity for the aminopurine p2 transporter. the diamidine and the hydroxy or methoxy group may be involved in binding to the dna minor groove. thus multiple modes of action may be the reason for promising anti-trypanosomal propertries of 2-phenylbenzofuran derivatives. thus these compounds require further assessment in order to develop as newer antitrypanosomal agents with promising pharmacokinetic profile. since a prodrug of furamidine, 2,5-bis[4-(n-methoxy)amidinophenyl]furan (pafuramidine), has shown promising results in clinical trials against hat [36] , therefore furamidine ( figure 11a ) has gained attention for further evaluation to produce newer antitrypanosomal analogous. two other analogues of furamidine (figure 11b &c) have been evaluated against t. b. rhodesiense mouse model and have shown promising results. one approach to enhance the activity of furamidine has been the replacement of the central furan ring with other heterocyclic systems, including thiophene, pyrrole, oxazole, oxadiazole, thiadiazole, pyridazine, methylpyrimidine, and triazine [37] [38] [39] [40] [41] . such structural modification in past has resulted into compound with good anti-parasitic activity. for example in 1977 boykin dw and das pb have reported the synthesis and antiprotozoal activity of eighteen substituted 2,5-bis(4-guanylphenyl)furans and related analogues, including "masked" amidines in which the guanyl function was incorporated into a heterocyclic ring. among these, six compounds have produced cures in mice at submilligram dosage levels and have been somewhat more active in this screen than stilbamidine, hydroxystilbamidine, and pentamidine. . 11 . structure of furamidine and its analogue that have shown promising antitrypanosomal properties tidwell rr et al [43] has recently synthesized a series of 3,5-diphenylisoxazole analogues ( figure 12 ), in which the central ring of furamidine was replaced by isoxazole, and their activities with furamidine and melarsoprol were compared. among 43 synthesized dications, the compounds with at least one p-amidine moiety (compound 22, figure 13a and compound 3, figure 13b ), displayed good ic 50 values (3.5 nm and 5.1 nm respectively) comparable to that of furamidine (4.3 nm) while loss in potency was observed in compounds with substituted diamidine at m-position (compound 32, ic 50 =29 nm, figure 13c ). in general, the introduction of nitro, chloro, or methoxy substituents on either aromatic ring resulted in decreased anti-trypanosomal activity. however, the introduction of methoxy group on the aromatic rings of compound 32 resulted into compound 41 ( figure 13b ) with comparable anti-trypanosomal activity (4.2 nm) as that of furamidine. hence these compounds of the isoxazole series that showed good in vitro antitrypanosomal activity and less cytotoxcity profile relative to furamidine, could be a candidate for further evaluation against animal models of the diseases. however in vivo evaluation of the present 3,5-diphenylisoxazole series has not been reported yet. [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] and also because 1,4-diphenyl-1,2,3-triazoles showed geometrical resemblance to furamidine. it was observed that the cytotoxicities of triazoles were as lower compared to that of pentamidine and were not affected by the alkylation on the amidine groups or the substitution on the aromatic rings. however, the placement of the cationic moiety in the 4-position increased the cytotoxicities of diamidines 46 ( figure 15 ) with respect to the pentamidine. except few, majority of unsubstituted diamidines exhibited higher in vitro activities against t. brucei rhodesiense than bis(n-isopropyl)amidines and diimidazolines. the compounds with cationic fragments in the 5,5'-position (compounds 1-15, figure 14a the replacement of central furan ring of furamidine either by isoxazole or 1,2,3-triazole resulted into compounds with better activity than that of furamidine. position and the nature of the cationic substituent governed the anti-trypanosomal activity of the two series. in general the para substituted diamidines in both the series were the most promising compounds with good activity. thus these compounds should be further evaluated to produce better analogue of furamidine the recent report on n,n'-bis(4-amidinophenyl)piperazine (figure 16) , which was shown to be very effective in vivo anti-trypanosomal agent has attracted the interest in this compound [56] . hence in search for new hat chemotherapy dardonville c et al [57] decided to carry out an in vitro screening of a total of 62 compounds against the parasite t. brucei rhodesiense taken from their in-house library. based on this they showed that bisguanidine and especially bis(2-aminoimidazoline)diphenyl compounds displayed potent anti-trypanosomal activity in vitro and vivo against t. b. rhodesiense, the causative agent of acute hat [58, 59] . among the 62 compounds screened, compounds1c, 28b, 32b and 41b ( figure 17 ) showed excellent in vitro activity (49nm, 69 nm, 22 nm and 118 nm respectively) as well as high selectivity (>5294, 3072, 29.5 and 881respectively) for the parasite. these studies revealed that compounds bearing 2-aminoimidazoline cations had higher selectivity for the parasite and similar activities with respect to their guanidine counterparts. in addition, a correlation between anti-trypanosomal activity and dna binding affinity was observed, suggesting a possible mechanism of action for these compounds. those molecules that showed an excellent in vitro activity as well as high selectivity for the parasite represent new anti-trypanosomal lead compounds. fig. 16. n,n'-bis(4-amidinophenyl) piperazine in light of these promising results, bis(2-aminoimidazoline) derivatives deserve more investigation as anti-trypanosomal agents and dna minor groove binders. the synthesis and study of new derivatives and prodrugs of these lead compounds is ongoing. progress has also been made on targets other than dna minor grove. in addition to newer targets some new lead compounds have also been identified with proper antitrypanosomal activity but uncertain mechanism of action. the enzyme trypanothione reductase (tr) which restores the oxidized trypanothione to reduced state has evolved as an effective drug target. many inhibitors of this enzyme have been developed but most of them combat with problems related to bioavailability, pharmacokinetics and metabolism. despite this quinolines have evolved as most important class of compounds against tr due to their broad spectrum of activity, excellent pharmacological and pharmacokinetic properties such as high plasma levels, high clearance, oral and parenteral applicability, chemical stability and rare side effect. in view of this gilbert ih [60] reported the screening of 62000 compound libraries against t. brucei. high through put screening (hts) which resulted into identification of two novel compound series active against the enzyme trypanothione reductase. series 1 was based on the quinoline scaffold (figure 18a ) in which compound 2 (figure 19a) with methylfuran group at r 3 position, br at 6 th position of quinoline ring and n-methylethanamine group at r 1 position was the most potent and significant tr inhibitor with tr inhibitory activity of 1.1 µm. according to sar study the replacement of methylfuran with other groups like furan, phenyl, pyridinyl, thiophene led to decrease in activity. also the replacement of br with h or f reduced the activity while cl group retained the activity. at 4 th position the nh and nme groups were equally active. the alkylamines at r 1 were active whereas the simple alkyl or aryl groups led to inactive compounds. the second series was based on the pyrimidopyridazine scaffold (figure 18b) , in which the compound 49 ( figure 19b ) showed promising inhibitory activity of 2.6 µm. in case of series 2 replacement of methyl group at r 1 position by h led to the decrease in activity. at r 2 position methyl and ethyl group showed activity while the h and chain extensions to propyl, butyl and cyclopentane led to decrease in activity. substituted phenyl and alkenylphenyl group at r 3 position gave the most active compound of the series. thus these quinoline compounds with promising activity could serve as lead compounds for further development of targeted drugs against african trypanosomiasis. in addition to this synthetic optimization study based on the lead anti-trypanosomal compound 1,2-dihydro-2,2,4-trimethylquinolin-6-yl 3,5-dimethoxybenzoate ( figure 20 ) was undertaken by werbovetz ka et al [61] in an attempt to discover new trypanocides with potent in vivo activity targeting tr enzyme. in course of this a total of 53 compounds were evaluated in vitro for their anti-trypanosomal activity and cytotoxicity. the compounds with oxygen atom at 6 th position were the most active compounds in the series, for example compound 9 ( figure 21 ) showed better anti-trypanosomal activity (0.007 µm) and low cytotoxicity (6.8 µm) than melarsoprol (ic 50 = 0.008µm and cytotoxicity = 7.9µm). whereas compounds lacking the 6-oxygen atom or bearing an oxygen atom at the 7-position rather than the 6-position were far less potent than those containing an alcohol or acyloxy group at the 6-position. compounds carrying aliphatic or a 2-phenylacetyl ester side chains were as potent and selective as their benzoylated or acetylated counterparts. however compound 9a was unstable due to auto-oxidation, so the unstable alcohols were esterified to generate prodrug 10a ( figure 21 ) having promising activity of 0.014µm against these parasites and a selectivity index of 1700. the in vivo evaluation of compound 10a in a murine model of african trypanosomiasis showed good results as the prodrug extended the lifespan of mice infected with t. b. brucei. thus compound 10a can serve as lead compound for further investigation of this class of molecules as potential candidates against hat. efforts are also be undertaken to further elucidate the metabolism, pharmacokinetics, and the anti-trypanosomal mechanism of action of this novel and promising class of compounds. dna topoisomerases have evolved as an effective drug target in prokaryotic and eukaryotic systems as these enzyme mediate mechanistic interactions such as supercoiling, relaxation, knotting or catenating of dna double helices. based on their mechanism of action, topoisomerases can be classified as type i enzymes, which break a single strand of the dna helix during the catalytic cycle, and type ii enzymes, which make double-stranded breaks. on the basis of primary sequence and reaction mechanism, type i topoisomerases are further subdivided into type ia and type ib. recently shapiro ta et al [62] evaluated the activity of indenoisoquinolines (figure 22) , originally known to have anti-cancer activity, against t. brucei and found that most of the compounds showed in vitro activity at submicromolar concentrations. the compound 12 ( figure 23 ) with propylamino group at r 6 position and methoxy group at r 2 , r 3 and r 9 was the most active one with in vitro anti-trypanosomal activity of 0.05 µm. the compound also showed good in vivo activity as it delayed parasitemia and extended survival in infected mice. according to structure-activity analysis the compounds with enhanced potency included alkylamino substitutions on n-6, methoxy groups on c-2 and c-3, and a methylenedioxy bridge between c-8 and c-9. testing of indenoisoquinolines with promising activity on l1210 mouse leukemia cells revealed all the compounds were more effective against trypanosomes than against mammalian cells. the indenoisoquinolines also showed appreciable water solubility indicating that these compounds have good quality for drug development. these compounds showed their anti-trypanosomal action by multiple mechanisms. the study indicated that they stabilize topoisomerase-dna complexes in situ and may also impede topoisomerase binding to dna. these agents markedly inhibited dna synthesis by interfering with topoisomerase and possibly other dna-metabolizing enzymes. concentrations in the range of 300 ng/ml up to 900 ng/ml. some of the dupont compounds, developed as anti-tumour drugs, were highly active but also showed high cytotoxicity on ht-29 cells. it was observed that the position r 1 and position r 2 in the quinolone core nucleus was not prerequisite for anti-trypanosomal activity and also substitution at r 8 position was not necessary for trypanocidal activity. thus, based on the result obtained from sar analysis special attention should be given to r 7 position and the tetracyclic derivatives. the in vivo results of these compounds were very poor, as none of the compounds evaluated produced cure of mice in dose escalation experiment up to 100mg/kg i.p. however no signs of toxicity were observed during the experiments. the in vivo ineffectiveness had not been explained and no drug level determination in the plasma of the treated mice was performed. polyamines are generally involved in growth and differentiation [64] [65] [66] [67] within the cell and their analogs are also used as anticancer agents, antiparasitic agents, antidiarrhoeals, anti-hiv agents, metal chelators, and gene delivery agents. since the inhibition of the initial polyamine biosynthesis enzyme, ornithine decarboxylase, by dl-α-difluoromethylornithine (dfmo) is toxic to african trypanosomes cells, [68, 69] polyamines can become a promising anti-trypanosomal compound. dfmo [70] [71] [72] is the most recently developed agent for late stage t. b. gambiense and t. b. brucei sleeping sickness, but has not been active against all strains of t. b. rhodesiense. the major drawbacks of dfmo are its cost, the duration of treatment and its availability. recent clinical studies have investigated that dmfo can be used in combination with clinically used trypanocides including suramin, nifurtimox and melarsoprol [73, 74] . these combinations result in significant reduction in dfmo dosage and time of administration. initial clinical study has shown that dfmo + nifurtimox are superior to dfmo + melarsoprol and melarsoprol + nifurtimox. the dfmo + nifurtimox regimen (nect regimen) allowed reduction in dfmo regimen from 14 to 7 days (56 versus 28 infusions) with a 94% cure rate and are associated with significantly reduced adverse side effects as compared to melarsoprol-based therapy. the success of the combined regimen has been most likely due to ability of dmfo to reduce trypanothione levels and resistance to oxidative stress and the ability of nifurtimox to generate oxidative stress. recently gilbert et al [76] designed, synthesized, and evaluated substituted polyamines, carrying 1,3,5-triazine units, as potential anti-trypanosomal drugs. preliminary results indicated that this route might be successful, and lead structure a (figure 26 ) was used as a starting point for the synthesis of two series of analogues. in the first series, the influence of structural changes of the central core unit was investigated while in the second series, the effect of additional methyl substituents on the 1,3,5-triazine was studied. the compounds were designed with the intention to selectively target the interior of t. brucei via the p2 amino-purine transporter. in the first series the compound containing the ndodecyl chain as core unit, showed weak activity against t. b. rhodesiense. the compound with n-nonyl chain was the most promising compound and its various analogues were designed by replacing nh 2 groups on the triazine ring with nhme and nme 2 groups. introduction of one or two methyl groups per triazine unit resulted in a 10fold increase in anti-trypanosomal activity. when four methyl groups per triazine unit were introduced, an 80-fold increase in activity was observed. similarly, replacement of nh 2 group in n-dodecyl chain led to 2-20-fold higher anti-trypanosomal activity for the methylated derivatives. monosubstituted compounds showed a slight increase in activity against t. b. rhodesiense as compared to the disubstituted compounds. the methylamino substituted triazines attached to the c9-(compound 8c, figure 27 ) or c12-(compound 8f, figure 27 ) polyamine precursor via an additional ch 2 linker resulted in most active trypanocidal compounds(ic 50 of 8c = 0.27µm and 8f = 0.18 µm). beside good activity, the compounds showed poor in vivo activity producing no cure to the infected mice and concentrations greater than 10 mg kg −1 induced severe acute toxicity. the actual mode of action for the reported triazine substituted polyamines remains unclear. so to understand and improve the activities of these compounds, further research has to verify intracellular drug targets and possible metabolic pathways. stanislaw fw et al [77] have reported the anti-trypanosomal activity of 5'-deoxy-5'-(e)-(iodomethylene)adenosine, which is a known inhibitor of adohcy hydrolase, [78, 79] the 5'-deoxy-5'-(e)-(iodomethylene)adenosine (eiddha) and its 6-n cyclopropyl analogue (figure 28a , b) have shown promising in vitro inhibitory activity (ic50 at 9 and 12 μg/ml) against t. brucei. the utilization of adenosine analogues as anti-parasitics should be explored as a therapeutic paradigm, as it has been shown previously that inhibitors of adohcy hydrolase are also very potent inhibitors against the growth of plasmodium falciparum [79] . this class of 6-n-cyclopropyl adenosine analogues modified at carbon 5', does not exhibit an inhibitory effect on human or parasite forms of the enzyme and displays only marginal antiviral activity in comparison to analogues which have been unmodified at 6-amino position (that are potent inhibitor of adohcy hydrolase). therefore these compounds require further structural modification in order to develop newer analogues with improved activity against t. brucei. the synthesis of 4-[5-(4-phenoxyphenyl)-2h-pyrazol-3-yl] morpholine derivatives by perozzo r et al [80] resulted in to the discovery of newer class of anti-trypanosomal compounds having stage specific action, as these compounds have shown moderate to very good activity against the blood stage of t. b. rhodesiense. the two compounds, 4-[3-(4-phenoxyphenyl)-1h-pyrazol-5-yl]morpholine (1.0µm) ( figure 29a ) and 1-[3-(4-phenoxyphenyl)-1h-pyrazol-5-yl]piperazine (1.1 µm) (figure 29b ) with a pyrazol ring, are the most potent anti-trypanosomals of the series and have same cytotoxicity (61.6 µm), indicating that the pyrazol ring is very important for anti-trypanosomal activity. the substitution of pyrazol ring with isoxazole derivative leads to a six fold reduction in activity as compared to the most potent compound. in addition, substitution with nitrophenyl or aminophenyl also results in strong reduction in activity. the phenoxy ring in the compounds is also important for activity as replacing it by an ethylene group results in nine fold reduction in efficacy. further substitution with a nitro group or an amino group reduces potency up to 4-fold or 18-fold respectively. the stage specific action of these compounds is unknown. further optimization of this class of compounds is required in order to lower the cytotoxicity profile of the compound. in vitro evaluation of a series of n-, s-, and cooh-blocked glutathione derivatives have been carried out by d'silva and daunes [81] against bloodstream form trypanosoma brucei trypomastigotes, to identify the determinants necessary for activity and for further development into an active lead structure. the results shows that n, s-blocked glutathione diesters are the most active inhibitors of t. brucei parasites and that n-acetyl-s-benzyloxycarbonylglutathione dimethyl ester (compound 5) and the n,s-benzyloxycarbonyl-s-2,4dinitrophenylglutathione diester derivatives (compounds 17-19 & 21) (figure 30 ) represent lead structures possessing minimal toxicity which potentially could be developed further to yield a therapeutically active agent for the treatment of trypanosomiasis. pentamidine, furamidine and its analogues lack oral bioavailability [82, 83] .in addition several analogues of furamidine show excellent activity on intravenous dosing but are ineffective on oral administration [83, 84] . generally, oral administration is the preferred dosing regime, and hence, prodrug strategies for diamidines that have the potential to overcome their limited oral bioavailability merit attention. the following works have been performed by boykin dw et al to develop prodrugs. boykin dw et al [85] syhthesized and evaluated five o-alkoxyamidine analogues of the prodrug 2,5-bis [4-methoxyamidinophenyl] furan against trypanosoma brucei rhodesiense in the stib900 mouse model by oral administration. it was observed that the size of the o-alkyl side-chain determined the metabolic stability of the prodrugs. the prodrugs with the o-methyl analogue were most susceptible to metabolism while the larger o-n-butyl and o-n-hexyl groups were least susceptible to metabolism. the in vivo studies in the stib900 mouse model for t. b. rhodesiense showed that compounds with an o-methoxy-amidine or o-ethoxyamidine group effectively cured all trypanosome-infected mice, whereas prodrugs with larger side-chains did not completely cure the mice. therefore the o-alkoxyamidine prodrugs, where the alkyl chain is less than three carbons, could effectively be used as prodrugs for amidines. in addition to above mentioned prodrug synthesis boykin dw et al [86] also reported that bis-amidoximes and bis-o-alkylamidoximes of a number of diamidine systems are effective prodrugs. in order to develop orally effective anti-trypanosomal agents, they synthesized these two types of potential prodrugs in the terphenyl series. it was found that compound 10b and 10d ( figure 32 ) showed good activity in the range of 2 nm. among these compounds 10b had lower cytotoxicity (6.4μm) profile but had very poor in vivo activity (cured none of the infected animal in stib900 mouse model). whereas compound 10d showed excellent in vivo activity, by curing all the infected animals upon oral administration in stib900 mouse model. to capitalize on the efficacy of these potent dications, other prodrugs that rely on different bioconversion pathways need to be developed. boykin dw et al [87] showed that some of the dicationic guanidine, n-alkylguanidine, and reversed amidine derivatives of fused ring systems have good in vitro activity against trypanosoma brucei rhodesiense [87, 88] . the dicationic n-isopropylguanidino-9hfluorene (12c, figure 33 ) showed promising in vivo biological results by giving 4/4 cures of the treated animals in the stib900 animal model for african trypanosomiasis. in addition the n-methyl analogue (12a, figure 33 ) also showed high activity giving 3/4 cures of the treated animals in the stib900 animal model for african trypanosomiasis. in order to enhance the oral bioavailability, two novel classes of potential guanidine prodrugs were prepared. the n-alkoxyguanidine derivatives 12d and 12e ( figure 33) were not effective as prodrugs. whereas the carbamate prodrugs (11c, figure 33 ), gave promising results with 4/4 cures on oral administration in the stib900 mouse model. the result showed that these compounds bind strongly to the dna minor groove, but despite strong bonding these compounds do not have high antiparasitic activity. as compared to the last 15 years, there has been a revival of drug research and development regarding neglected parasitic diseases, and a number of drug development projects are currently ongoing. however discovering lead compounds with anti-trypanosomal activity remains a crucial step to sustain the progress achieved till date. the use of computer-assisted drug design (cadd), since their start, has become increasingly helpful in understanding many aspects of chemical-biological interactions in drug and other scientific research. the latest technological advances (qsar, structure-based design, ligand-based design, cheminformatics & bioinformatics) are providing a much improved basis for the design of ligands and inhibitors with desired specificity. recently, computerassisted drug design approaches based on ligand-based and structure-based drug design have been successfully employed to develop new drugs for the treatment of cancer, aids and other diseases [89] [90] [91] [92] [93] [94] [95] [96] . qsar [97] has been widely used for years to provide quantitative analysis of structure and activity relationships of compounds. our core research group has also performed qsar analysis of dicationic diphenylisoxazoles [10] . in this study, attempt has been to investigate the relationship between the various physiochemical parameters and anti-trypanosomal activity of dicationic 3,5-diphenylisoxazoles that may be helpful in development of potent antitrypanosomal agents against sleeping sickness. several statistical expressions have been developed using stepwise multiple linear regression analysis (mlr) and partial least squares (pls). the best mlr model showed good correlative and predictive ability as shown in following equation 84 has also been obtained. the developed model has been validated by leave-one-out method of cross-validation and prediction of test set. the study indicates that the anti-trypanosomal activity is largely explained by cosmic energy, log p and total lipole descriptors. the qsar study has reported in present study provides important structural insights, related to anti-trypanosomal activity. authors have developed a validated and highly predictive model sharing important structural requirement for effective binding of anti-trypanosomal compounds to minor groove of t. b. rhodesiense dna. the model reported in the study should be helpful in development of new compounds with improved efficacy and oral bioavailability. in line to the developed model authors have also designed some molecules which showed good activity in silico. the further study of these compounds is in progress. the poor pharmacokinetic profile and toxicity produced by the drugs currently used to treat trypanosomiasis requires an immediate attention for the development of safe, economical and high affinity chemotherapeutic agents to meet the need for this class of drugs. the unacceptable truth is the lack of attention of the government and less interest of pharmaceutical companies in light of less monitory gain in the area of protozoal infection since most of the affected people belong to poorer country. surprisingly the endeavors of different research group discussed in this review belong to academic institutions. it is felt by the researchers that the treatment for hat requires a combined approach by government organization, pharmaceutical companies and academic institutions. the most promising fact is that in the last decade several synthetic approaches have been made in the field of development of anti-trypanosomal therapies. several compounds are being synthesized that yield new compounds for the treatment of hat, as a result of these synthetic approaches newer leads have been identified, which are under different phase of drug development. the promising in vitro and in vivo activities of dicationic molecules clearly indicate that aromatic diamidines are the most promising class of compounds for the development of newer drugs against hat. the most important one is the newer analogous of existing drugs pentamidine (compounds 32, figure 3e and 66, figure 3b ) which shows excellent in vivo and in vitro activity (0.004 and 0.001 μm respectively) and also has very good selectivity index against the parasite but is cytotoxic. in an attempt to synthesise newer compounds with reduced cytotoxicity than pentamidine molecules, several benzofuran derivatives have been synthesized. however the replacement of phenoxy fragement of pentamidine with a benzofuran motif has resulted in poor analogues with lower antitrypanosomal activity but improved cytotoxic profile. however the strong activity against t. b. rhodesiense isolates indicates that steps should be taken to initiate further studies of compound 66 and compound 32 which can be further evolved as new lead compound. the newer analogues of furamidine also show promising anti-trypanosomal activity along with lower cytotoxicity than furamidine. thus strong activity against t. b. rhodesiense and lower cytotoxicity of compound 3 (figure 13b ) indicates that these compounds should be further evaluated. thus the dna minor grove binders are still the most interesting and potential target for the development of newer anti-trypanosomal agents. apart from diamidines, polyamines and guanidine also have the potential to give antitrypanosomal compounds. the success of dmfo as polyamine inhibitors has attracted researchers for synthesis and development of agents targeting polyamine metabolism. recently polyamines carrying 1,3,5-triazine units have been synthesized and evaluated against t. brucei. these compound exhibited good activity but are cytotoxic. morpholine and dihydroquinolines have also shown promising in vivo anti-trypanosomal activity. in addition to this development of prodrugs, the existing compounds also promise to address the pharmacokinetic related problems, in near future. thus excellent in vitro and in vivo activities and high selectivity of aforementioned compounds merit further investigation in order to reduce the cytotoxicity that may result in development of newer anti-trypanosomal drug with reduced toxicity, improved efficacy and pharmacokinetic profile. as the drug discovery and development process is expensive in terms of time and money, the cross application of existing series of compounds with selective trypanocidal activity may be the best prospect to new anti-trypanosomal drugs in the short term. more emphasis has to be put in the field of cadd approaches for development of anti-trypanosomal agents as cadd study reduces the time and cost required for development of newer analogues. the trypanosomiases african trypanosomiasis (sleeping sickness) the fall and rise of sleeping sickness treatment of human african trypanosomiasis-present situation and needs for research and development chemotherapy of human african trypanosomiasis: current and future prospects human african trypanosomiasis. cook gc, zumla a, editors. in manson's tropical diseases chemotherapy of human african trypanosomiasis current chemotherapy of human african trypanosomiasis quantitative structure activity relationship analysis of dicationic diphenylisoxazole as potent anti-trypanosomal agents new approaches to the development of anti-protozoan drug candidates: a review of patents small molecule dna and rna binders; from synthesis to nucleic acid complexes treatment perspectives for human african trypanosomiasis challenges and new discoveries in the treatment of leishmaniasis treatment and control of human african trypanosomiasis the biochemical basis of arsenicaldiamidine crossresistance in african trypanosomes transporters in african trypanosomes: role in drug action and resistance adenosine transporters in bloodstream forms of trypanosoma brucei brucei: substrate recognition motifs and affinity for trypanocidal drugs a drug resistance determinant in trypanosoma brucei synthesis and trypanocidal activity of the bis-carba analogue of pentamidine structure-activity relationships of analogs of pentamidine against plasmodium falciparum and leishmania mexicana amazonensis analogues of 1,5-bis(4-amidinophenoxy)pentane (pentamidine) in the treatment of experimental pneumocystis carinii pneumonia trypanocidal activity of conformationally restricted pentamidine congeners structure-activity study of pentamidine analogues as antiprotozoal agents synthesis and antiprotozoal activity of 2,5-bis(4-guanylphenyl)furans synthesis and antiprotozoal activity of aza-analogues of furamidine accumulation and intracellular distribution of anti-trypanosomal diamidine compounds db75 and db820 in african trypanosomes synthesis and antiprotozoal activity of pyridyl analogues of pentamidine design and synthesis of a series of melamine-based nitroheterocycles with activity against trypanosomatid parasites trypanocide diamidine mit drei ringen in zwei isolierten ringsystemen trypanocide diamidine mit vier ringen in einem oder zwei ringsystemen synthesen biskationischer, trypanocider 1-benzofuran-verbindungen synthesis and in vitro antiprotozoal activity of bisbenzofuran cations synthesis and antiprotozoal activity of cationic 2-phenylbenzofurans synthesis and antiprotozoal properties of pentamidine congeners bearing the benzofuran motif db-289 immtech international synthesis and antiprotozoal activity of 2, 5-bis(4-guanylphenyl)furans synthesis and anti-trypanosomal activity of some bis(4-guanylphenyl) five-and six-membered ring heterocycles anti-pneumocystis carinii pneumonia activity of dicationic diaryl methylpyrimidines synthesis of dicationic diaryltriazines nucleic acid binding agents 4-diphenylfurandiamidines as novel anti-pneumocystis carinii pneumonia agents trypanocidal diamidines with three isolated ring systems synthesis and in vitro antiprotozoal activities of dicationic 3,5-diphenylisoxazoles superoxide dismutase-like activity of 1, 2, 3-triazole derivatives synthesis and muscarinic activities of quinuclidin-3-yltriazole and -tetrazole derivatives 3-triazoles: synthesis and evaluation of antiinflammatory and analgesic properties i 3-triazoles: synthesis and evaluation of antiinflammatory and analgesic properties ii bioisosteres of arecoline: 1,2,3,6-tetrahydro-5-pyridyl-substituted and 3-piperidyl-substituted derivatives of tetrazoles and 1,2,3-triazoles. synthesis and muscarinic activity synthesis and biological evaluation f novel 2-pyridinyl-[1,2,3]triazoles as inhibitors of transforming rowth factor beta 1 type 1 receptor rapid discovery and structure-activity profiling of novel inhibitors of human immunodeficiency irus type 1 protease enabled by the copper(i)-catalyzed synthesis of 1,2,3-triazoles and their further functionalization synthesis and biological evaluation of 4-aryl-5-cyano-2h-1, 2, 3-triazoles as inhibitor of her2 tyrosine kinase synthesis, hiv-rt inhibitory activity and sar of 1-benzyl-1h-1, 2, 3-triazole derivatives of carbohydrates 3-triazole derivatives as new cannabinoid cb1 receptor antagonists synthesis and cb1 cannabinoid receptor affinity of 4-alkoxycarbonyl-1,5-diaryl-1,2,3-triazoles trypanocidal activity of conformationally restricted pentamidine congeners new bis(2-aminoimidazoline) and bisguanidine dna minor groove binders with potent in vivo antitrypanosomal and antiplasmodial activity dna binding affinity of bisguanidine and bis(2-aminoimidazoline) derivatives with in vivo antitrypanosomal activity and polyamine derivatives as potent and selective chemotherapeutic agents against trypanosoma brucei rhodesiense. synthesis and in vitro evaluation investigation of tryoanothione reductase as a target in trypanosoma brucei activity of 1,2-dihydroquinolin-6-ols and their ester derivatives activity of indenoisoquinolines against african trypanosomes evaluation of quinolone derivatives for anti-trypanosomal activity biological activity and synthesis of polyamine analogues and conjugates synthesis of polyamines, their derivatives, analogues and conjugates polyamines as targets for therapeutic intervention trypanosoma brucei ornithine decarboxylase -enzyme purification, characterization, and expression in escherichia-coli polyamine metabolism: a potential therapeutic target in trypanosomes advances in sleeping sickness therapy safety and effectiveness of first line eflornithine for trypanosoma brucei gambiense sleeping sickness in sudan: cohort study three drug combinations for late-stage trypanosoma brucei gambiense sleeping sickness: a randomized clinical trial in uganda nifurtimox eflornithine combination therapy for second-stage trypanosoma brucei gambiense sleeping sickness: a randomized clinical trial in congo cure of trypanosoma brucei brucei and trypanosoma brucei rhodesiense infections in mice with an irreversible inhibitor of s-adenosylmethionine synthesis and biological evaluation of s-triazine substituted polyamines as potential new anti-trypanosomal drugs anti-trypanosomal activity of 5'-deoxy-5'-(iodomethylene) adenosine and related 6-n-cyclopropyladenosine analogues synthesis of 6' (e and z)-halohomovinyl derivatives of adenosine, inactivation of s-adenosyl-lhomocysteine hydrolase, and correlation of anticancer and antiviral potencies with enzyme inhibition structure, evolution, and inhibitor interaction of s-adenosyl-l-homocysteine hydrolase from plasmodium falciparum synthesis and evaluation of antiparasitic activities of new 4 structure-activity study on the in vitro antiprotozoal activity of glutathione derivatives dicationic diaryl furans as anti-pneumocystis carinii agents anti-pneumocystis activity of aromatic diamidoxime prodrugs 5-bis[4-(n-alkylamidino)phenyl]furans as pneumocystis carinii agents prodrugs of furamidine: in vitro transport and microsomal metabolism as indicators of in vivo efficacy in a mouse model of trypanosoma brucei rhodesiense infection dna affinity, and antiprotozoal activity of linear dications: terphenyl diamidines and analogues synthesis, dna affinity, and antiprotozoal activity of fused ring dicationic compounds and their prodrugs prodrugs for amidines: synthesis and anti-pneumocystis carinii activity of carbamates of 2,5-bis rational design of potent sialidase-based inhibitors of influenza virus replication bis tertiary amide inhibitors of the hiv-1 protease generated via protein structure-based iterative design structure-based inhibitor design by using protein models for the development of antiparasitic agents conformation-activity relationship study of 5-ht3 receptor antagonists and a definition of a model for this receptor site 3-hydroxy-3-methylglutaryl-coenzyme. a reductase: molecular modeling, three-dimensional structureactivity relationships, inhibitor design a 3d model of sars_cov 3cl proteinase and its inhibitors design by virtual screening a novel strategy for improving ligand selectivity in receptor-based drug design corona virus main proteinase (3clpro) structure: basis for design of anti-sars drugs correlation of biological activity of phenoxyacetic acids with hammett substituent constants and partition coefficients 3d qsar on a library of heterocyclic diamidine derivatives with antiparasitic activity activity of bisphosphonates against trypanosoma brucei rhodesiense qsar study on the contribution of log p and es to the in vitro antiprotozoal activity of glutathione derivatives authors pay sincere thanks to prof. aditya shastri, vice chancellor, banasthali university and dr. monali bhattacharga, dept. of english, banasthali university, rajasthan, india. the author declares no conflict of interest key: cord-296769-xnjmk4pm authors: valentová, kateřina title: cytoprotective activity of natural and synthetic antioxidants date: 2020-08-06 journal: antioxidants (basel) doi: 10.3390/antiox9080713 sha: doc_id: 296769 cord_uid: xnjmk4pm numerous chronic diseases including cancer, cardiovascular, chronic respiratory or neurodegenerative diseases, diabetes mellitus, retinal damage, and others are associated with oxidative stress [...]. mimetic, chelating agent, and intravenous magnetic resonance imaging agent mangafodipir showed preventive and protective effects against oxaliplatin-induced neurotoxicity in balb/c mice [14] . a growing number of studies deal with the mechanism of action of cytoprotection. the cytoprotective mechanism of natural anthocyanin delphinidin against oxidative stress induced by h 2 o 2 was investigated in human chondrocytes where it inhibited reactive oxygen species (ros)-induced apoptosis via activation of nrf2 and nuclear factor κb (nf-κb) and activated cytoprotective autophagy showing potential in the treatment of osteoarthritis [15] . embelin, a plant natural product from lysimachia punctata and embelia ribes fruit with quinone and hydroquinone functional groups plus a long hydrophobic tail completely abolished the superoxide radical generated in situ with hydrodynamic voltammetry. moreover, it exhibited cytoprotective activity in thp-1 human leukemic monocytes and bv-2 mice microglia probably thanks to its long alkyl tail enabling its insertion in cell membranes [16] . the mechanism of anti-inflammatory and antioxidant effects of aspirin on hyperoxia-induced acute lung injury was studied in nf-κb-luciferase transgenic mice. pretreatment with aspirin significantly reduced the protein levels of phosphorylated protein kinase b, nf-κb, and tumor necrosis factor α, indicating that aspirin reduces nf-κb activation [17] . a few publications were devoted to the effect of natural compounds in the form of complex but well-characterized extracts. thus, the essential oil from feijoa (acca sellowiana) fruit peal containing mostly sesquiterpenes showed strong antioxidant and free radical scavenging activity, cytoprotective activity on lymphocytes pre-treated with 100 µm tert-butylhydroperoxide (t-booh), as well as a decrease in intracellular ros, induced by t-booh on erythrocytes and antimicrobial and antifungal activities against staphylococcus aureus and candida albicans, respectively [18] . vitis vinifera var. fetească neagră tendrils and leaves extracts, intended to be used in oral hygiene products recommended in periodontal disease, displayed a cytoprotective effect against nicotine-induced cytotoxicity and anti-inflammatory activity in human gingival fibroblasts [19] . viburnum opulus berry phenolic extracts were able to decrease the uptake of glucose, free fatty acids, and accumulation of lipid droplets in caco-2 cells without affecting their viability, followed by a decrease in the cd36/fat gene expression, without influence on the glut2 and pparα levels. furthermore, the extracts revealed strong chemo-preventive activity against oxidative stress induced chemically by t-booh, as well as against dna damage through the induction of dna repair after cell exposition to methylnitronitrosoguanidine and h 2 o 2 [20] . in a subsequent study, v. opulus fruit fresh juice and a phenolic-rich fraction were able to decrease intracellular oxidative stress in mice insulinoma min6 cells, induced glucagon-like peptide-1 secretion in the presence of an elevated glucose concentration, and inhibited in vitro activity of the dipeptidyl peptidase-4 [21] . several publications in this special issue study flavonolignans from silymarin, an extract from the fruits of silybum marianum. twenty-six commercially available silymarin preparations, natural silymarin from sigma aldrich, and a model mixture of pure flavonoid/flavonolignans mimicking the silymarin composition, all analyzed by u-hplc-hrms/ms, were compared using biochemical (2,2 -azino-bis-(3-ethylbenzothiazoline-6 sulfonic acid) (abts), oxygen radical absorption capacity (orac), and 2,2-diphenyl-1-picrylhydrazyl (dpph)) and cellular (caa) antioxidant tests and significant differences in the antioxidant capacity of the supplements were observed [22] . antioxidant activities of pure stereomers a and b of silybin and 2,3-dehydrosilybin, their racemic mixtures, pure silychristin a, and its derivatives (anhydrosilychristin, isosilychristin, and 2,3-dehydrosilychristin a) were investigated by using orac and caa assays. moreover, their anti-inflammatory activity was studied in macrophages and multidrug resistance modulation as inhibition of p-glycoprotein and sensitization of doxorubicin-resistant ovarian carcinoma cells overproducing p-glycoprotein was detected and the effect on related gene expression revealed a distinct mechanism of action for the individual compounds [23, 24] . last but not least, new potential targets of silymarin constituents silybin and dehydrosilybin as dual inhibitors of braf and the hedgehog pathway receptor smoothened (smo), two major targets in anticancer therapy, were identified in silico and confirmed in vitro [25] . the content of the special issue clearly shows that cytoprotection by anti-and prooxidant active molecules is still a hot topic. however, for effects demonstrated in cell cultures other than those derived from the gastrointestinal tract, the bioavailability and metabolism of the active compounds often could not be taken into consideration. therefore, future studies should be directed towards the effects of the metabolites likely to be present in blood plasma. antioxidant and oxidative stress: a mutual interplay in age-related diseases the nrf2 system as a potential target for the development of indirect antioxidants the importance of antioxidants which play the role in cellular response against oxidative/nitrosative stress: current state direct and indirect antioxidant properties of inducers of cytoprotective proteins european contribution to the study of ros: a summary of the findings and prospects for the future from the cost action bm1203 (eu-ros) oxidative stress, aging, and diseases antioxidants: friend or foe? asian pac oxidative stress in cardiovascular diseases: still a therapeutic target? nutrients a bibliometric review of the keap1/nrf2 pathway and its related antioxidant compounds potential cytoprotective activity of ozone therapy in sars-cov-2/covid-19 aop1, a new live cell assay for the direct and quantitative measure of intracellular antioxidant effects the side effects of platinum-based chemotherapy drugs: a review for chemists quantification of berberine in berberis vulgaris l. root extract and its curative and prophylactic role in cisplatin-induced in vivo toxicity and in vitro cytotoxicity calmangafodipir reduces sensory alterations and prevents intraepidermal nerve fibers loss in a mouse model of oxaliplatin induced peripheral neurotoxicity cytoprotective effects of delphinidin for human chondrocytes against oxidative stress through activation of autophagy antioxidant properties of embelin in cell culture. electrochemistry and theoretical mechanism of scavenging. potential scavenging of superoxide radical through the cell membrane anti-inflammatory and reactive oxygen species suppression through aspirin pretreatment to treat hyperoxia-induced acute lung injury in nf-κb-luciferase inducible transgenic mice feijoa fruit peel: micro-morphological features, evaluation of phytochemical profile, and biological properties of its essential oil phytochemical profile and biological activities of tendrils and leaves extracts from a variety of vitis vinifera l viburnum opulus fruit phenolic compounds as cytoprotective agents able to decrease free fatty acids and glucose uptake by caco-2 cells evaluation of viburnum opulus l. fruit phenolics cytoprotective potential on insulinoma min6 cells relevant for diabetes mellitus and obesity complex evaluation of antioxidant capacity of milk thistle dietary supplements multidrug resistance modulation activity of silybin derivatives and their anti-inflammatory potential antioxidant, anti-inflammatory, and multidrug resistance modulation activity of silychristin derivatives dual smo/braf inhibition by flavonolignans from silybum marianum. antioxidants 2020 key: cord-253276-mqcwk2ow authors: desai, n. c.; bhatt, nayan; somani, hardik; trivedi, amit title: synthesis, antimicrobial and cytotoxic activities of some novel thiazole clubbed 1,3,4-oxadiazoles date: 2013-09-30 journal: european journal of medicinal chemistry doi: 10.1016/j.ejmech.2013.06.029 sha: doc_id: 253276 cord_uid: mqcwk2ow abstract a series of thiazole clubbed 1,3,4-oxadiazole derivatives (5a–l) have been synthesized and characterized by ir, 1h nmr, 13c nmr and mass spectral analysis. synthesized compounds were evaluated for their antimicrobial and cytotoxic activities. the results indicated that, compounds 5c and 5i exhibited the most potent antibacterial activity. compound 5f was found to be the most potent antifungal agent. the structure activity relationship revealed that the presence of electron withdrawing groups at para position of phenyl ring remarkably enhanced the antibacterial activity of synthesized compounds. further, the results of preliminary mtt cytotoxicity studies on hela cells suggested that potent antimicrobial activity of 5b, 5c, 5f, 5h and 5i is accompanied by low cytotoxicity. the treatment of infectious diseases still remain a challenging task because of combination of factors such as an alarming increase in number of multi-drug-resistant microbial pathogens and advent of newer infectious diseases such as severe acute respiratory syndrome (sars), and avian influenza. despite the availability of a large number of antibiotics and chemotherapeutics, the increasing clinical importance of drug-resistant microbial pathogens have lent additional urgency in microbiological and antifungal research [1e4] . a potential solution to the antibiotic resistance is to design and explore innovative heterocyclic agents with novel mode of actions. in this context, thiazole derivatives have been playing a crucial role in medicinal chemistry. thiazole nucleus constitutes an integral part of all the available penicillins, which have transformed the bacterial diseases therapy [5] . they display quite a broad spectrum of biological activities [6] , which have found applications in the treatment of allergies [7] , hypertension [8] , inflammation [9] , schizophrenia [10] , microbial infections [11, 12] , hiv infections [13] , hypnotics [14] and pain [15] . they are also used as new inhibitors of bacterial dna gyrase b [16] . further, thiazoles have emerged as new class of potent antimicrobial agents, which are reported to inhibit bacteria by blocking the biosynthesis of certain bacterial lipids and/ or by additional mechanisms [17, 18] . on the other hand, 1,3,4-oxadiazole heterocycles are very good bioisosteres of amides and esters, which can contribute substantially in enhancing pharmacological activity by participating in hydrogen bonding interactions with the receptors [19] . potent pharmacological activity of 1,3,4-oxadiazoles can be attributed to the presence of toxophoric en]ceoe linkage which may react with the nucleophilic centers of the microbial cell [20] . further, the widespread use of 1,3,4-oxadiazoles as a scaffold in medicinal chemistry established this moiety as a member of the privileged structures class and its derivatives have exhibited a wide range of biological activities such as antibacterial [21] , antitubercular [22] , vasodialatory [23] , antifungal [24] , cytotoxic [25] , anti-inflammatory and analgesic [26, 27] , hypolipidemic [28] , anticancer [29] and ulcerogenic [30] . oxadiazole derivatives have been found to possess broad spectrum antimicrobial activity and therefore are useful substructures for further molecular exploration [30] . the most prominent examples of prescribed agents featuring the 1,3,4-oxadiazoles nucleus include the antiretroviral raltegravir [31] , antihypertensive nesapidil [32] and the antibiotic furamizole [33] (fig. 1) . prompted by above-mentioned observations and in continuation of our search for new, potent, selective, and less toxic antimicrobial agents [34e39], we report herein the synthesis of some novel structural hybrids by combining thiazole and 1,3,4oxadiazole pharmacophores in single molecular framework in order to investigate their in vitro antimicrobial activity. in addition, cytotoxicity studies were also conducted in hela cell lines to evaluate the ability of these compounds to inhibit the cell growth. the substitution pattern of 1,3,4-oxadiazole ring was carefully selected in order to confer different electronic environment to the molecules. the reaction sequences employed for synthesis of the target compounds 5ael are outlined in scheme 1. ethyl 2-amino-4methylthiazole-5-carboxylate (1) was taken as starting material and reacted with acetic anhydride to afford ethyl 2-acetamido-4methylthiazole-5-carboxylate (2) , which on further reaction with hydrazine hydrate in absolute ethanol yielded intermediate n-(5-(hydrazine carbonyl)-4-methylthiazol-2-yl)acetamide (3) . the intermediate obtained thus, was refluxed with carbon disulfide in the presence of potassium hydroxide in ethanol (99.5%) to yield intermediate n-(4-methyl-5-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2yl)thiazol-2-yl)acetamide (4) . mannich condensation of intermediate 4 with 36% formaldehyde and an appropriately substituted aniline derivative in ethanol (99.5%) furnished the desired compounds 5ael. both analytical and spectral data of the synthesized compounds 5ael were fully in agreement with proposed structures. formation of titled compounds 5ael was confirmed by characteristic ir spectrum absorption bands in the range of 3330e 3350 cm à1 , 3200e3250 cm à1 , 2810e2840 cm à1 , 2750e2800 cm à1 and 1660e1690 cm à1 corresponding to enh stretching of secondary amine, enh stretching of amide, ech 3, ech 2 e and >c]o of amide respectively. singlets at around d 2.03e2.10, 2.40e2.50, 4.15e4.25, 4.35e4. 45 and 9 .10e9.20 ppm in 1 h nmr were due to e ch 3 in anilide group, hetech 3 , secondary amine, ech 2 e and enh amide group respectively. the aromatic ring protons were observed at d 6.20e8.05 ppm and j value were found to be in accordance with substitution pattern on phenyl ring. characteristic peaks at around d 168.5e168. 9 and 177.0e177.3 ppm in 13 c nmr confirmed the presence of >c]o and >c]s groups respectively. the mass spectrum of 5ael revealed that observed molecular ion peaks were in agreement with molecular weight of respective compound. all the synthesized compounds 5ael were evaluated for their in vitro antibacterial activity against staphylococcus aureus mtcc 96, streptococcus pyogenes mtcc 442 (gram-positive), escherichia coli mtcc 443 and pseudomonas aeruginosa mtcc 1688 (gramnegative) by conventional broth microdilution method using chloramphenicol as a control drug for antibacterial activity [40] . the results of the antimicrobial studies are presented in table 1 . in general, compounds 5ael demonstrated better antibacterial activity than antifungal activity. compounds 5c and 5i emerged as the most effective antibacterial agents with 2-to 4-fold higher mic (12.5e25 mg/ml) than the reference drug chloramphenicol. while, compounds 5b and 5h exhibited comparable antibacterial activity with the standard drug. from the results of the antimicrobial activity of the synthesized compounds 5ael, the following structure activity relationships can be derived: the antibacterial activity was considerably affected by substitution pattern on the phenyl ring and the most active compounds contain electron withdrawing substituent at para and meta positions of the phenyl ring (p > m > o). in contrast, the presence of electron releasing groups on the phenyl ring witnessed a substantial decrease in antibacterial activity for compounds 5def and 5kel. the role of electron withdrawing group in improving antimicrobial activity is very well supported by previous studies [41, 42] . compounds 5c and 5i, substituted with inductively electron withdrawing fluoro and nitro groups, respectively at para position showed the highest antibacterial activity (f > no 2 ). it is a very well-known fact that electron withdrawing substitution such as fluoro/nitro at the para position of the aromatic ring increases the lipophilicity of molecules. this property is directly related to antimicrobial activity as it facilitates a compound to diffuse through the biological membranes and reach to its site of action. the presence of lipophilic substituent at para position of phenyl ring provided a positive influence on antibacterial activity. on the other hand, presence of the same functional groups at meta position resulted in slight decrease in the antibacterial activity (5b and 5h) but, still produced significant inhibitory action compared to the standard drug chloramphenicol (f > no 2 ). while, substituting the phenyl ring with fluoro and nitro group at ortho position resulted in noticeable decrease in the antibacterial activity of compounds 5a and 5g respectively. on the basis of mic values, it may be concluded that electron withdrawing atom/group such as fluoro and nitro at the para position of phenyl ring induced a positive effect while electron donating groups such as methyl and methoxy induced a negative effect on antibacterial activity of compounds 5ael. the in vitro antifungal activity of synthesized compounds 5ael were determined against candida albicans mtcc 227, aspergillus niger mtcc 282 and aspergillus clavatus mtcc 1323 by conventional broth microdilution method. the results indicated that compound 5f substituted with methoxy group at para position of the phenyl ring was found to be the most promising agent against both c. albicans and a. niger having 2-fold higher mic (25 mg/ml) in comparison with control drug ketoconazole. the enhanced activity of compound 5f may be attributed to the presence of electron releasing group at para position. the contrasting nature of substitution pattern at para position of the phenyl ring of most active antibacterial and antifungal agents indicate that the structural requirements are different for binding of drug to bacterial or fungal targets, respectively [43] . all other compounds showed less inhibition against the tested microorganisms as compared to the standard drug. in vitro cytotoxicity of compounds 5b, 5c, 5f, 5h and 5i were evaluated against human cervical cancer cell line (hela) by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (mtt) colorimetric assay [44] , which measures the reduction of tetrazolium bromide salt into a formazan dye by mitochondrial dehydrogenases in treated versus untreated cells. the results are summarized in table 2 . it was observed that none of the tested compounds exhibited any significant cytotoxic effect on hela cells, suggesting a great potential for their in vivo use as antimicrobial agents. in conclusion, some new structural hybrids of thiazole and 1,3,4oxadiazole were synthesized and investigated for their antimicrobial property with an anticipation of generating new structural leads serving as potent antimicrobial agents. many of the synthesized motifs (5b, 5c, 5h and 5i), possessing electron withdrawing atom/group such as fluoro and nitro at para and meta positions were identified as the most potent antibacterial agents. albeit, it was observed that para position was more favorable for enhancing the antibacterial activity. while, compound 5f with electron releasing group at para position came out as the most promising antifungal agent. the potent antimicrobial activity of most active compounds 5b, 5c, 5f, 5h and 5i were accompanied with relatively low level of cytotoxicity. the results described here, merits further investigations in our laboratories using a forward chemical genetic approach for finding lead molecules as antimicrobial agents. all reactions except those in aqueous media were carried out by standard techniques for the exclusion of moisture. melting points were determined on an electrothermal melting point apparatus and were reported uncorrected. tlc on silica gel plates (merck, 60, f 254 ) was used for purity checking and reaction monitoring. column chromatography on silica gel (merck, 70e230 mesh and 230e400 mesh asth for flash chromatography) was applied when necessary to isolate and purify the reaction products. elemental analysis (% c, h, n) was carried out by a perkineelmer 2400 chn analyzer. ir spectra of all compounds were recorded on a perkine elmer ft-ir spectrophotometer in kbr. 1 h nmr spectra were recorded on varian gemini 300 mhz and 13 c nmr spectra on varian mercury-400 100 mhz in dmso-d 6 as a solvent and tetramethylsilane (tms) as an internal standard. mass spectra were scanned on a shimadzu lc-ms 2010 spectrometer. all reactions requiring anhydrous conditions were carried out under nitrogen atmosphere using oven-dried glassware. ethyl 2-amino-4-methylthiazole-5-carboxylate (0.01 mol) was taken in a round bottom flask and acetic anhydride (0.02 mol) was added. the reaction mixture was refluxed at 140e150 c for 1 h and then poured into cold water under constant stirring to get solid product. the mixture was heated to boiling to decompose excess of acetic anhydride and cooled. the solid obtained was filtered, washed with water and dried. the ethyl 2-(acetyl amino)-4methyl-1,3-thiazole-5-carboxylate was collected and recrystallized from ethanol to get pure white crystals. yield: 74%; m.p. 158 c; anal. obs. c, 47.08%; h, 5.48%; n, 12.44%. calcd. for c 9 h 12 n 2 o 3 s: c, 47.35%; h, 5.30%; n, 12.27%. intermediate (2) (0.01 mol) and 99% hydrazine hydrate (0.015 mol) were taken in a round bottom flask and mixture was refluxed for 10 min. alcohol was added till both the layers were miscible and refluxing was continued for 5 h. excess of alcohol and unreacted hydrazine hydrate was distilled out and the contents were poured into a beaker. the solid was recrystallized from ethanol to get pure crystalline product. dmso was used as diluents to get desired concentration of compounds to test upon standard bacterial strains. serial dilutions were prepared in primary and secondary screening. the control tube containing no antibiotic was immediately subcultured (before inoculation) by spreading a loopful evenly over a quarter of plate of medium suitable for the growth of the test organism and put for incubation at 37 c overnight. the tubes were then incubated overnight. the mic of the control organism was read to check the accuracy of the compound concentrations. the mic was defined as the lowest concentration of the antibiotic or test sample allowing no visible growth. all the tubes showing no visible growth (same as control tube) were subcultured and incubated overnight at 37 c. the amount of growth from the control tube before incubation (which represents the original inoculum) was compared. subcultures might show: similar number of colonies indicating bacteriostatic; a reduced number of colonies indicating a partial or slow bactericidal activity and no growth if the whole inoculum has been killed. the test must include a second set of the same dilutions inoculated with an organism of known sensitivity. each synthesized compound was diluted obtaining 2000 mg/ml concentration as a stock solution. in primary screening 500, 250 and 200 mg/ml concentrations of the synthesized compounds were taken. the active synthesized compounds found in this primary screening were further tested in a second set of dilution against all microorganisms. the compounds found active in primary screening were similarly diluted to obtain 100, 62.5, 50 and 25 mg/ml concentrations. the highest dilution showing at least 99% inhibition is taken as mic. in vitro cytotoxicity was determined using a standard mtt assay with protocol appropriate for the individual test system. test compounds were prepared prior to the experiment by dissolving in 0.1% dmso and diluted with medium. the cells were then exposed to different concentrations of the drugs (1e100 mm) in the volume of 100 mm/well. cells in the control wells received the same volume of medium containing 0.1% dmso. after 24 h, the medium was removed and cell cultures were incubated with 100 ml mtt reagent (1 mg/ml) for 5 h at 37 c. the suspension was placed on micro vibrator for 10 min and absorbance was recorded by the elisa reader. the experiment was performed in triplicate. human cancer cell lines, hela cells were cultured in mem medium supplemented with 10% fbs, 1% glutamine and 50 mm/ml gentamicin sulphate in a co 2 incubator in a humidified atmosphere of 5% co 2 and 95% air. ir (kbr): v/cm à1 3329 (secondary amine nh), 3225 (secondary amide nh), 3010 (aromatic ring ch -nitrophenyl)amino)methyl)-5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)thiazol-2-yl)acetamide (5i) yield: 60%, m.p. 159e161 c; ir (kbr): v/cm à1 3331 (secondary amine nh), 3227 (secondary amide nh) (o-tolylamino)methyl)-4,5-dihydro-1,3,4-oxadiazol-2-yl)thiazol-2-yl)acetamide (5j) yield: 62%, m.p. 142e144 c; ir (kbr): v/cm à1 3331 (secondary amine nh), 3220 (secondary amide nh (m-tolylamino)methyl)-4,5-dihydro-1,3,4-oxadiazol-2-yl)thiazol-2-yl)acetamide (5k) yield: 57%, m.p. 151e153 c; ir (kbr): v/cm à1 3330 (secondary amine nh), 3229 (secondary amide nh anal. calcd. for c 16 h 17 n 5 o 2 s 2 c-51 p-tolylamino)methyl)-4,5-dihydro-1,3,4-oxadiazol-2-yl)thiazol-2-yl)acetamide (5l) yield: 61%, m.p. 163e165 c; ir (kbr): v/cm à1 3327 (secondary amine nh) anal. calcd. for c 16 h 17 n 5 o 2 s 2 c-51 we would like to express our sincere gratitude to the department of chemistry, mahatma gandhi campus, maharaja krishnakumarsinhji bhavnagar university, bhavnagar for providing research and library facilities. key: cord-281597-x53ni6q1 authors: chiasson, melissa a; rollins, nathan j; stephany, jason j; sitko, katherine a; matreyek, kenneth a; verby, marta; sun, song; roth, frederick p; desloover, daniel; marks, debora s; rettie, allan e; fowler, douglas m title: multiplexed measurement of variant abundance and activity reveals vkor topology, active site and human variant impact date: 2020-09-01 journal: elife doi: 10.7554/elife.58026 sha: doc_id: 281597 cord_uid: x53ni6q1 vitamin k epoxide reductase (vkor) drives the vitamin k cycle, activating vitamin k-dependent blood clotting factors. vkor is also the target of the widely used anticoagulant drug, warfarin. despite vkor’s pivotal role in coagulation, its structure and active site remain poorly understood. in addition, vkor variants can cause vitamin k-dependent clotting factor deficiency or alter warfarin response. here, we used multiplexed, sequencing-based assays to measure the effects of 2,695 vkor missense variants on abundance and 697 variants on activity in cultured human cells. the large-scale functional data, along with an evolutionary coupling analysis, supports a four transmembrane domain topology, with variants in transmembrane domains exhibiting strongly deleterious effects on abundance and activity. functionally constrained regions of the protein define the active site, and we find that, of four conserved cysteines putatively critical for function, only three are absolutely required. finally, 25% of human vkor missense variants show reduced abundance or activity, possibly conferring warfarin sensitivity or causing disease. the enzyme vitamin k epoxide reductase (vkor) drives the vitamin k cycle, which activates blood coagulation factors. vkor, an endoplasmic reticulum (er) localized transmembrane protein encoded by the gene vkorc1, reduces vitamin k quinone and vitamin k epoxide to vitamin k hydroquinone (li et al., 2004; rost et al., 2004) . vitamin k hydroquinone is required to enable gamma-glutamyl carboxylase (ggcx) to carboxylate gla domains on vitamin k-dependent blood clotting factors. vkor is inhibited by the anticoagulant drug warfarin (czogalla et al., 2017; zimmermann and matschiner, 1974) , and vkorc1 polymorphisms contribute to an estimated~25% of warfarin dosing variability (owen et al., 2010) . for example, variation in vkorc1 noncoding and coding sequence can cause warfarin resistance (weekly warfarin dose >105 mg) or warfarin sensitivity (weekly warfarin dose <~10 mg) (osinbowale et al., 2009; yuan et al., 2005) . though 15 million prescriptions are written for warfarin each year (https://www.clincalc.com), fundamental questions remain regarding its target, vkor. for example, the structure of human vkor is unsolved, though a bacterial homolog has been crystallized . a homology model based on bacterial vkor has four transmembrane domains, but the quality of the homology model is unclear, as human vkor has only 12% sequence identity to bacterial vkor. moreover, experimental validation of vkor topology yielded mixed results: similar biochemical assays suggested either three-or four-transmembrane-domain topologies tie et al., 2012; shen et al., 2017; wu et al., 2018) . topology informs basic aspects of vkor function including where vitamin k and warfarin bind, so determining the correct topology and validating the homology model is critical. in particular, vkor has four functionally important, absolutely conserved cysteines at positions 43, 51, 132, and 135, the orientation of which differs between the two proposed topologies. in the four transmembrane domain topology, all four cysteines are located on the er lumenal side of the enzyme. in this topology, cysteines 43 and 51 are hypothesized to be 'loop cysteines' that pass electrons from an eranchored reductase, possibly transmembrane thioredoxin-related protein , to the active site (rishavy et al., 2011) . however, in the three transmembrane domain topology, these cysteines are located in the cytoplasm and other pathways would be required to convey electrons to the redox center. even for non-catalytic residues, topology plays an important role. for example, vitamin k presumably binds near the redox center, and topology dictates which residues make up the substrate binding site. to understand the effect of human variants and to define the vitamin k and warfarin binding sites, vkor variant activity has been extensively studied in cell-based assays (czogalla et al., 2017; shen et al., 2017; tie et al., 2013) . in addition to activity, vkor protein abundance has also been studied because abundance is an important driver of disease and warfarin response. for example, vkor r98w is a decreased-abundance variant that, in homozygous carriers, causes vitamin k-dependent clotting factor deficiency 2 . a 5' utr polymorphism reduces vkor abundance and can be used to predict warfarin sensitivity (gong et al., 2011) . however, so far, the activity and abundance of only a handful of vkor variants has been tested. here, we used multiplexed, sequencing-based assays (gasperini et al., 2016) to measure the effects of 2,695 vkor missense variants on abundance and 697 variants on activity. our analysis of the large-scale functional data supports a four transmembrane domain topology, which an orthogonal evolutionary coupling analysis confirmed. next, we identified distinct mutational tolerance groups, which are concordant with a four transmembrane homology model. combining this homology model with variant abundance and activity effects, we identified an active site that contains the catalytic residues c132 and c135 and shares six positions with a previously proposed vitamin k binding site (czogalla et al., 2017) . we found that of four conserved cysteines putatively critical for function, only three are absolutely required, and analyzed the mutational signatures of two putative er retention motifs. human vkorc1 variants present in genetic databases and contributed by a commercial genetic testing laboratory were each classified based on abundance and activity. while most variants show wild type-like activity, 25% show low abundance or activity, which could confer warfarin sensitivity or cause disease in a homozygous context. finally, we analyzed warfarin resistance variants and found that they span a range of abundances, indicating that increased abundance is an uncommon mechanism of warfarin resistance. to measure the abundance of vkor variants, we applied variant abundance by massively parallel sequencing (vamp-seq), an assay we recently developed (matreyek et al., 2018) . in vamp-seq, a protein variant is fused to egfp with a short amino acid linker. if the variant is stable and properly folded, then the egfp fusion will not be degraded, and cells will have high egfp fluorescence. in contrast, if the variant causes the protein to misfold, protein quality control machinery will detect and degrade the egfp fusion, leading to a decrease in egfp signal (figure 1a) . mcherry is also expressed from an internal ribosomal entry site (ires) to control for expression. differences in abundance are measured on a flow cytometer using the ratio of egfp to mcherry signal. to determine abundance score egfp:mcherry ratio figure 1 . multiplexed measurement of vkor variant abundance using vamp-seq. (a) to measure abundance, an egfp reporter is fused to vkor. egfp-tagged wt vkor is folded correctly, leading to high egfp fluorescence. however, a destabilized variant is degraded by protein quality control machinery, leading to low egfp fluorescence. (b) flow cytometry is used to bin cells based on their egfp:mcherry fluorescence intensity. density plots of vkor library expressing cells (grey, n = 12,109) relative to three controls: wt vkor (red, n = 4,756), vkor 98w (blue, n = 2,453), and vkor tmd1d (orange, n = 2,204) are shown. quartile bins for facs of the library are marked. (c) abundance score density plots of nonsense variants (dashed blue line, n = 88), synonymous variants (dashed red line, n = 127), and missense variants (filled, solid line, n = 2,695). the missense variant density is colored as a gradient between the lowest 10% of abundance scores (blue), the wt abundance score (white) and abundance scores above wt (red). (d) heatmap showing abundance scores for each substitution at every position within vkor. heatmap color indicates abundance scores scaled as a gradient between the lowest 10% of abundance scores (blue), the wt abundance score (white), and abundance scores above wt (red). grey bars figure 1 continued on next page whether vamp-seq could be applied to vkor, we fused egfp to vkor n-or c-terminally and found that both orientations had high egfp signal (figure 1-figure supplement 1) . we compared n-terminally tagged wild type (wt) vkor to r98w, a variant that ablates a putative er retention motif and reduces abundance (czogalla et al., 2014) , and to tmd1d, a deletion of residues 10-30 which comprise the putative first transmembrane domain (tmd1; figure 1b ). both reduced abundance variants exhibited much lower egfp:mcherry ratios than wt, demonstrating that vamp-seq could be applied to vkor. we constructed a barcoded site-saturation mutagenesis vkor library that covered 92.5% of all 3240 possible missense variants. to express this library in hek293t cells we used a bxb1 recombinase landing pad system we previously developed (matreyek et al., 2017) . in this system, each cell expresses a single vkor variant. recombined, vkor variant-expressing cells were then sorted into quartile bins based on their egfp:mcherry ratios. each bin was deeply sequenced, and abundance scores were calculated based on each variant's distribution across bins. raw abundance scores were normalized such that wt-like variants had a score of one and total loss of abundance variants had a score of zero ( figure 1c) . we performed seven replicates, which were well correlated (figure 1-figure supplement 1, mean pearson's r = 0.73; mean spearman's r = 0.7, supplementary file 1). abundance score means and confidence intervals for each variant were calculated from the replicates. the final dataset describes the effect of 2695 of the 3240 possible missense vkor variants on abundance (figure 1d and e). validation of 10 randomly selected variants spanning the abundance score range showed high concordance between individual egfp:mcherry ratios assessed by flow cytometry and vamp-seq derived abundance scores (figure 1f , pearson's r = 0.96, spearman's r = 0.97). western blots of these variants also showed high concordance with abundance scores (figure 1-figure supplement 2). we also measured vkor variant activity, adapting a hek293 cell assay based on vitamin k-dependent gamma-glutamyl carboxylation of a cell-surface reporter protein (haque et al., 2014) . in this assay, if vkor is active, a factor ix domain reporter is carboxylated, secreted and retained on the cell surface where it is detected with a carboxylation-specific, fluorophore-labeled antibody. however, if vkor is inactive, the reporter is not carboxylated and the antibody cannot bind (figure 2a) . we modified the hek293 activity reporter cell line to eliminate endogenous vkor activity by knocking out both vkorc1 and its paralog, vkorc1-like 1 (vkorc1l1) (tie et al., 2013; figure 2-figure supplement 1) . we also installed a bxb1 landing pad to facilitate expression of individual vkor variants or libraries (figure 2-figure supplement 1) . recombination of wt vkorc1 into the landing pad of the hek293 vkor activity reporter cell line yielded robust reporter activation, demonstrating that the reporter line could be used to assess the activity of a library of vkor variants (figure 2b ). we recombined a library of vkorc1 variants into the hek293 activity reporter cell line and sorted recombinant cells into quartile bins based on carboxylation-specific antibody binding. each bin was deeply sequenced and, as for vamp-seq, an activity score was computed for each variant. final activity scores and confidence intervals were computed from six replicates for a total of 697 comparing vamp-seq derived abundance scores to mean egfp:mcherry (n = 1 replicate) ratios measured individually by flow cytometry. variants were selected at random to span the abundance score range. error bars show standard error for abundance scores and standard error for egfp:mcherry ratio. the online version of this article includes the following source data and figure supplement(s) for figure 1: source data 1. vkor variant abundance and activity scores. source data 2. flow cytometry for monoclonal validation of variants. reporter is expressed inhek293 cells and consists of a prothrombin pre-pro-peptide which allows for processing and secretion, a factor ix gla domain, and proline rich gla protein 2 (prgp2) transmembrane and cytoplasmic domains. middle panel, cells expressing wt vkor carboxylate the reporter gla domain, which, upon trafficking to the cell surface, can be stained using a carboxylation-specific antibody conjugated to the fluorophore apc. right panel, vkor knockout cells do not carboxylate the reporter, so the fluorescent antibody does not bind. (b) density plots of hek293 activity reporter cells stained with apc-labeled carboxylation-specific antibody expressing no vkor (blue, n = 7,188), wt vkor (red, n = 4,107), or the vkor variant library (grey, n = 41,418). quartile bins for facs of the library are marked. (c) activity score density plots of nonsense variants (dashed blue line, n = 14), synonymous variants (dashed red line, n = 35), and missense variants (filled, solid line, n = 697). the missense variant density is colored as a gradient between the lowest 10% of activity scores (blue), the wt activity score (white) and activity scores above wt (red). the online version of this article includes the following figure supplement(s) for figure 2: two different domain models, one with three transmembrane domains and another with four, have been proposed for human vkor tie et al., 2012; figure 3a) . because charged amino acids occur infrequently in transmembrane domains and should be less tolerated, we reasoned we could discriminate between these two models using a sliding window average of the effect of charged substitutions on vkor abundance (elazar et al., 2016a; sharpe et al., 2010) . we found four clearly demarcated regions where charged substitutions profoundly reduced vkor abundance, relative to aliphatic substitutions ( figure 3b) . to exclude the possibility that the egfp tag used in our vamp-seq assay somehow affected topology, we also analyzed the activity score data. the activity data, derived using native, untagged vkor, revealed the same four minima as the abundance data ( figure 3c ). in addition to these four minima, we also observed an activity score minimum at position 57, corresponding to a conserved serine at this position. this serine occurs at the end of the lumenal half-helix hypothesized to shield the active site from non-specific oxidation, so it is likely this signal is the result of disruption of that half helix. together, these results strongly support the hypothesis that, like its distant bacterial homolog, human vkor has four transmembrane domains. to validate these findings, we performed evolutionary coupling analysis to infer the three-dimensional structure suggested by co-evolution. we aligned 6910 vkor sequences from both eukaryotes and prokaryotes (1118 sequences from eukaryotes, 5731 from bacteria, and 61 from environmental samples and viruses) and identified coupled residues using the evcouplings software (hopf et al., 2012; marks et al., 2011) . local patterns of evolutionary couplings (i.e. between nearby positions, i to i+4) supported a four-helix topology. the helices predicted by these local evolutionary couplings overlapped 70 of the 82 residues in alpha-helices of the bacterial structure (pdb 4nv5) (shen et al., 2017) and included in our alignment (hyper-geometric test p-value=3.26 à23 , figure 3d ). we identified non-local evolutionary coupling patterns characteristic of three-dimensional contacts, which also strongly supported the four transmembrane domain model. using these contacts, we computationally folded human vkor, yielding a modeled structure similar to the bacterial structure (rmsd = 2.58 å over 97/143 c alpha , figure 3 comparison of our abundance data to the energy required to insert different amino acids into the membrane yielded additional evidence for the four transmembrane domain model. the apparent change in free energy (ddg app ) of insertion relative to wild type for every amino acid has been determined experimentally using deep mutational scanning of bacterial membrane proteins (elazar et al., 2016a) . median abundance score and ddg app for each amino acid are correlated ( figure 3h ). in particular, the large energetic cost of insertion of transmembrane domains with charged amino acids is apparent, including within the second transmembrane domain tmd2. beyond insertion energies of individual amino acids, the overall hydrophobicity of transmembrane helices contributes to membrane protein insertion (elazar et al., 2016a) , as well as topology (elazar et al., 2016b) and degradation (guerriero et al., 2017) . to determine whether overall helix hydrophobicity was a large factor contributing to abundance scores, we calculated the free energy for insertion (dg helix ) of each helix in the four transmembrane domain model using the dg prediction server v1.0 (hessa et al., 2007) and topgraph (elazar et al., 2016b) . both predicted that transmembrane domain three had the most favorable dg helix for insertion (dg prediction server: tmd1: 0.435, tmd2: 1.551, tmd3: à1.749, and tmd4: 1.734; topgraph: tmd1: à6.3, tmd2: à5.5, tmd3: à12.6, tmd4: à4.3). interestingly, we observed that tmd3 has a high density of substitutions with wt-like scores (figure 3figure supplement 3a), suggesting that tmd3's favorable insertion energy might explain its mutational tolerance. in addition, the high concordance of hydrophobicity indices from bacterial and mammalian multiple sequence alignments further supports the conservation of a four transmembrane domain topology between bacteria and mammals ( having confirmed that human vkor has four transmembrane domains, we next explored the detailed pattern of mutational effects we observed in the context of a four transmembrane domain homology model. we generated a homology model of human vkor with i-tasser using the bacterial vkor structure (shen et al., 2017; yang et al., 2015, supplementary file 4) . we performed hierarchical clustering of positions based on abundance scores, which yielded four groups of positions with characteristic mutational patterns ( figure 4a ). in group 1, most substitutions were neutral or increased abundance; in group 2, charged amino acid and proline substitutions decreased abundance; in group 3, all substitutions decreased abundance; and in group 4, all substitutions decreased abundance profoundly. each group corresponded to a spatially distinct region of the homology model structure (figure 4b) . group one positions were located in or adjacent to cytoplasmic and er lumenal loops, which were more tolerant of substitutions than the transmembrane domains. at four group one positions, k30, r33, r35, and r37, almost every substitution increased abundance. these positively charged positions are positioned either at the edge of tmd1 (k30) or in the er lumen directly abutting the top of tmd1 (r33, r35, and r37). the 'positive inside rule ' (von heijne, 1989) , suggests that positive charges in membrane proteins generally reside in the cytoplasm, and this phenomenon is important for driving topology and membrane insertion (elazar et al., 2016b; nilsson and von heijne, 1990; von heijne, 1989) . k30, r33, r35, and r37 violate the positive inside rule, and substitutions at these positions may increase abundance by reducing charge inside the er, reducing topological frustration or increasing membrane insertion efficiency. compared to the other 12 arginine and lysine positions in wt vkor, k30, r33, r35, and r37 are the only ones where substitutions generally increased abundance (figure 4-figure supplement 1). our observations are consistent with a screen of rat vkor variants intended to improve protein expression in e. coli where deletion of positions 31 to 33 increased protein levels (hatahet et al., 2015) . in group two, charged amino acids or proline substitutions generally decreased abundance. group two consisted mostly of transmembrane positions that had side chains projecting into the lipid bilayer. such transmembrane positions usually have hydrophobic, nonpolar side chains (ulmschneider and sansom, 2001) . proline has poor helix forming propensity, explaining why proline substitutions decreased abundance at these positions. group 3 consisted of a mixture of cytoplasmic, er lumenal and transmembrane positions where most substitutions decreased abundance. the cytoplasmic positions in this group included the putative dilysine er localization motif at positions 159 and 161. also in this group were r98, part of another putative er retention motif at positions 98 and 100, and a glycine adjacent to tmd1 at position nine. the transmembrane positions had side chains projecting towards neighboring transmembrane helices, suggesting that, as for other membrane proteins (fleming and engelman, 2001; mravic et al., 2019) , intramolecular sidechain packing is important for abundance. finally, substitutions in group 4, consisting of positions g19, y88, i141, and l145, resulted in catastrophic loss of abundance. these positions are all in transmembrane domains with side chains projecting into the interior of the protein. on the basis of strict mutational intolerance of these positions, we hypothesized that their coordinated side chain packing comprises the core of the vkor four helix bundle. indeed, group four residues had dramatically lower relative solvent accessibility than groups 1-3 ( figure 4c) . the four transmembrane domain homology models also allowed us to explain vkor's unusual trimodal distribution of variant abundance scores. previous vamp-seq derived abundance score distributions for the cytosolic proteins tpmt and pten were bimodal (figure 4-figure supplement 2; matreyek et al., 2018) , and 15 of 16 deep mutational scans of other soluble proteins using a variety of other assays also exhibited bimodal functional score distributions (gray et al., 2017) . because vkor is an er resident, transmembrane protein, we hypothesized that its unusual trimodal abundance score distribution resulted from transmembrane domain substitutions. indeed, the lowest mode of the distribution was composed almost exclusively of deleterious transmembrane domain substitutions (figure 4d ). in contrast, the intermediate mode consisted of substitutions in the er lumen, cytoplasm, and transmembrane domains. similarly, substitutions that profoundly decreased activity occurred in transmembrane domains (figure 4e ). we reasoned that our activity and abundance data could reveal the location of functionally important positions in vkor, including the active site, since functionally important positions should have many loss-of-activity but few loss-of-abundance variants. thus, we calculated the specific activity for each variant by taking the ratio of its rescaled activity score and abundance score (see methods). we computed the median specific activity for each position; substitutions at positions with low median specific activity generally have low activity relative to their abundance. we set a specific activity threshold based on two absolutely conserved cysteines that form vkor's redox center, c132 and c135. using this threshold, positions with the lowest 12.5% of specific activity scores and with at least four variants scored for activity were deemed functionally constrained and mapped on the homology model of vkor ( , including f55, which is hypothesized to bind vitamin k. three functionally constrained positions, g60, r61, and a121, did not match any position in the predicted active site, but were immediate neighbors of w59 and l120, positions that are present in the predicted active site. besides c132 and c135, vkor has two additional absolutely conserved cysteines, c43 and c51. in the four transmembrane domain model, c43 and c51 are postulated to be loop cysteines that relay electrons to the c132/c135 redox center (liu et al., 2014) . we classified c43 as having low specific activity, but we only observed one variant at this position, so it was not included in our set of functionally constrained positions ( figure 5-figure supplement 2) . in contrast, substitutions at c51 resulted in only modest activity loss, a phenomenon that has been observed previously (shen et al., 2017) . interestingly, every substitution at c51 and 15 of 19 at c132 decreased vkor abundance ( figure 5-figure supplement 2) . inside cells, the majority of vkor molecules have a c51-c132 disulfide bond, and warfarin binds to this redox state of vkor (shen et al., 2017) . since disruption of this disulfide bond apparently impacts abundance as well as activity, this bond may be important for vkor folding and stability. vkor is thought to contain two sequences important for er localization. the first is a diarginine motif (rxr) at positions 98-100, and the second is a dilysine motif (kxkxx) at positions 159-163. while we did not directly measure localization, we found that only six of 19 r98 variants and seven of 14 r100 variants resulted in low abundance ( figure 5-figure supplement 3) . in contrast, nearly all variants at k159 (14 of 18) and k161 (17 of 19) resulted in low abundance ( figure 5-figure supplement 3) . a histidine substitution was tolerated at position 161, which mimics the kxhxx motif commonly found in coronaviruses and a small number of human proteins (ma and goldberg, 2013) . because protein localization and degradation are coupled (hessa et al., 2011) , we suggest that the reductions in abundance we observe are the result of degradation caused by mislocalization, and that the dilysine motif at positions 159-163 is essential for vkor er localization. overall, comparison of vkor variant activity and abundance revealed functionally important regions, refining our understanding of the active site, redox-active cysteines, and er retention motifs. (kabsch and sander, 1983; touw et al., 2015) and colored as in b. bold black line shows median, box shows 25th and 75th percentile. line shows 1.5 interquartile range above and below percentiles, and outliers are shown as black points. (d) histograms of abundance scores for missense variants in the cytoplasmic, er lumenal, or transmembrane domains. (e) histograms of activity scores for missense variants in the cytoplasmic, er lumenal, or transmembrane domains. the online version of this article includes the following figure supplement(s) for figure 4: variation in vkor is linked to both disease and warfarin response, but the overwhelming majority of vkor variants found in humans so far have unknown effects. thus, we curated a total of 215 variants that had either been previously reported in the literature as affecting warfarin response (supplementary file 5), were in clinvar (landrum et al., 2014) , were in gnomad v2 or v3 (karczewski et al., 2019) , or were present in individuals whose healthcare provider had ordered a multi-gene panel test from a commercial testing laboratory (color genomics) (supplementary file 6). of eight variants present in clinvar, we included only one (d36y) in our analysis as it was the only variant reviewed by an expert panel (kurnik et al., 2012) . 159 variants were present in gnomad, and all but one missense variant (d36y) had population frequencies less than 0.2%. 28 variants were literature-curated warfarin response variants, only 12 of which were in one of the databases surveyed. d36y was the only warfarin response variant present in all databases, clinvar, gnomad, and color ( figure 6-figure supplement 1) . we classified 193 of the 215 variants we curated according to their abundance (supplementary file 6). all synonymous variants with the exception of two were wt-like or possibly wt-like, while the three nonsense variants were scored as low abundance (figure 6a) . missense variants spanned all abundance categories, with 129 (60%) having wt-like or possibly wt-like abundance. 30 missense variants were low abundance, and 12 were high abundance. the single known pathogenic variant r98w was low abundance (figure 6b) . we also classified 54 variants according to their activity (supplementary file 6) . only one variant, a115v, exhibited low activity. it had wtlike abundance, indicating that the loss of activity is not due to loss of abundance. we examined warfarin response variants including w5x, the only variant observed so far linked to human warfarin sensitivity . as expected, w5x was low abundance, reinforcing that heterozygous loss of vkor is the cause of warfarin sensitivity in carriers of this variant. warfarin resistance variants, on the other hand, are predicted to abrogate warfarin binding , but it is unclear whether these variants have appreciable effects on abundance or activity. we found that warfarin resistance variants span a range of abundances and that the distribution of warfarin resistant variant abundance was not different from missense variants generally (figure 6c , twosided kolmogorov-smirnov test p=0.438). five warfarin-resistance variants had low abundance, suggesting that these variants must block drug binding or increase activity to confer resistance. one variant, a26t, had high abundance, a possible mechanism of warfarin resistance. the five warfarin resistance variants, r58g, w59l, v66m, g71a, and n77s, whose activity we scored, were all wtlike. thus, our abundance and activity data are consistent with warfarin resistance arising largely from variants that block warfarin binding. we conducted multiplexed assays to measure the effects of 2,695 vkor variants on abundance and 697 variants on activity. both abundance and activity data provided evidence for a four transmembrane topology, which was further supported by evolutionary couplings analysis. we evaluated a vkor homology model in the context of the patterns of variant effects on abundance we measured and found that the homology model could explain these patterns. low specific activity residues mapped onto this homology model identify, at least in part, the active site, which largely overlaps with the results of a vitamin k docking simulation (czogalla et al., 2017) . our active site is shallower than what the docking simulation predicts; this is the result of low abundance scores at some of the deeper, transmembrane positions predicted by docking to bind the isoprenoid chain of vitamin k (f87, y88), and poor coverage of activity scores for other positions (v112, s113). in light of the fact that substitutions at f87 and y88 resulted in low abundance, we note that the modeled vitamin k binding mode would disrupt packing of vkor core residues and require repacking of helices to maintain protein stability (merkle et al., 2018) . in addition to the active site, substitutions at the dilysine and, to a lesser extent, the diarginine er localization motifs caused abundance loss. we also used our large-scale functional data to analyze 215 vkor variants found in humans. 16% of these variants affect neither activity nor abundance; we identified 54 previously uncharacterized low abundance or low activity variants that could be pathogenic or alter warfarin response. we found that only one warfarin resistance variant had increased abundance, indicating that increased abundance is not a pervasive warfarin resistance mechanism. many of the other warfarin resistant variants have warfarin ic50s that are 10-to 100-fold higher than wildtype vkor in cell assays (shen et al., 2018) , and this high level of resistance probably cannot be gained through increased protein abundance alone. all five of the warfarin resistance variants whose activity we scored were wt-like. taken together these data support the notion that warfarin resistance generally involves alterations to warfarin binding rather than abundance or activity. we analyzed one known warfarin sensitivity variant, w5x, and found that it is low abundance, suggesting the possibility that any of the 53 other low abundance variants, if found in a person, might also confer warfarin sensitivity. while our vkor variant abundance and activity data illuminates various aspects of vkor's structure and function, the data have limitations. for example, neither assay captures variant effects on a b c 0.5 figure 6 continued on next page mrna splicing, which means we cannot determine the effect of human splice site variants on vkor activity or abundance. in addition, as a result of how these assays were engineered, both have limited dynamic ranges. thus, subtle effects on abundance or activity cannot be discerned, and it is difficult to translate the scores these assays generated to a more precise biochemical measure, like absolute vkor molecules present or enzymatic kinetics. in addition, both assays have inherent noise, largely arising from the limited number of cells we can sample due to the bottleneck of cell sorting. we account for this noise by filtering each dataset based on variant frequency and presenting a confidence interval for each abundance and activity score. reengineering the assay to be growth-based, instead of flow cytometry-based, would increase the number of cells sampled and would most likely improve library coverage and score estimation. in the future, we envision that the assays we used could be employed to better understand vkor's interaction with warfarin. here, we could measure warfarin's effect on both variant abundance and activity, mapping the warfarin binding site more finely. in addition, we could identify warfarin resistance mutations that have not yet been observed in the clinic and group variants by their putative resistance mechanism. overall, our work highlights the value of multiplexed assays of variant effect for better understanding protein structure, function and human variant effects. continued on next page source data 1. abundance and activity data for human variants found in clinvar, gnomad v2 and v3, and color genomics dataset. figure supplement 1 were cultured in dulbecco's modified eagle's medium supplemented with 10% fetal bovine serum, 100 u ml à1 penicillin, and 0.1 mg ml à1 streptomycin. cells were induced with 2.5 ug ml à1 doxycycline. cells were passaged by detachment with trypsin-edta 0.25%, and cells were prepared for sorting by detachment with versene. all cell lines tested negative for mycoplasma. cell line identity was not authenticated. because our activity assay is vitamin-k dependent, all activity assays were done with the same lot of fbs to ensure similar concentrations of vitamin k in each replicate. all synthetic oligonucleotides were obtained from idt and can be found in supplementary file 7. all non-library-related plasmid modifications were performed with gibson assembly (gibson et al., 2009 ). a gblock with a codon-optimized sequence for human vkor was ordered from idt. it was then cloned into the vector phsg298 (clontech). saturation mutagenesis primers were designed for each codon in vkor from positions 2 to 163 (jain and varadarajan, 2014) and ordered resuspended from idt. forward and reverse primers for each position were mixed at 2.5 mm, and used in a pcr reaction with 125 pg of phsg298-vkor, 5% dmso, and 5 ml of kapa hifi hotstart 2x readymix. pcr products were visualized on a 0.7% agarose gel to confirm amplification of the correct product. pcr products were then quantified using the quant-it picogreen dsdna assay kit (invitrogen) using dna control curves done in triplicate. to pool positions, a total amount of dna for each reaction was calculated that maximized the volume to be drawn from the lowest concentration pcr product. pooled pcr products were cleaned and concentrated using zymogen clean and concentrate kit and then gel extracted. the pooled library was phosphorylated with t4 pnk (neb), incubated at 37˚c for 30 min, 65˚c for 20 min, and then 4˚indefinitely. 8.5 ml of this phosphorylated product was combined with 1 ml of 10x t4 ligase buffer (neb) and 0.5 ml of t4 dna ligase (neb) to make a 10 ml overnight ligation reaction. this reaction was incubated at 16˚c overnight. the overnight ligation was then cleaned and concentrated (zymogen) and eluted in 6 ml of ddh2o. 1 ml of this ligation was then transformed into high efficiency e. coli using electroporation at 2 kv. each reaction contained 1 ml of ligation (or ligation control or puc19 10 pg/ul) and 25 ml of e. coli 975 ml of pre-warmed soc medium was added to each cuvette after electroporation, transferred to a culture tube, and recovered at 37˚c, shaking for 1 hr. at 1 hr, 1 and 10 ml samples from all cultures were taken and plated on appropriate medium (lb + kanamycin for ligation and ligation control; lb + ampicillin for puc19), the remaining 989 ml was used to inoculate a 50 ml culture (+ kanamycin). plates and 50 ml culture were incubated at 37˚c overnight (shaking for 50 ml culture). colonies on plates were then counted, and counts were used to calculate how many unique molecules were transformed to gauge coverage of the library. 50 ml culture was spun down and midiprepped. to transfer the library from phsg298 to the recombination vector, the phsg298 library and recombination vector were digested with xbai and aflii for 1 hr at 65˚c. the library and cut vector were then gel extracted. the library was then ligated with the cut vector at 5:1 using t4 ligase, overnight at 16˚c. the ligation was heat inactivated the next morning, clean and concentrated. another high efficiency transformation was performed the same as described above, except this ligation was plated on lb + ampicillin (antibiotic switching strategy). plates and 50 ml culture were incubated at 37˚c overnight (shaking for 50 ml culture). colonies on plates were then counted, and counts were used to calculate how many unique molecules had been transformed to gauge coverage of the library. a 50 ml culture was spun down and midiprepped. to barcode individual variants, plasmid library harvested from midiprep was digested with ecori-hf and ndei at 37˚c for 1 hr, 65˚c for 20 min. barcode oligos were ordered from idt, resuspended at 100 um, and then annealed by combining 1 ml each of primer with 4 ml cutsmart buffer and 34 ml ddh2o and running at 98˚c for 3 min followed by ramping down to 25˚c at à0.1˚c/second. after annealing, 0.8 ml of klenow polymerase (exonuclease negative, neb) and 1.35 ml of 1 mm dntps was then combined with the 40 ml of product to fill in the barcode oligo (cycling conditions: 25˚c for 15:00, 70˚c for 20:00, ramp down to 37˚c at à0.1˚c/s). digested vector and barcode oligo were then ligated overnight at 16˚c. the overnight ligation was then cleaned and concentrated and eluted in 6 ml of ddh2o. 1 ml of this ligation was then transformed into high efficiency e. coli using electroporation at 2 kv. each reaction contained 1 ml of ligation (or ligation control or puc19 10 pg/ul) and 25 ml of e. coli. 975 ml of pre-warmed soc medium was added to each cuvette after electroporation, transferred to a culture tube, and recovered at 37˚c, shaking for 1 hr. at 1 hr, 1 and 10 ml samples from water and puc19 cultures were taken and plated on lb supplemented with ampicillin. for ligation and ligation control, four flasks were prepared with 50 mls of lb and ampicillin, and then 500 ml, 250 ml, 125 ml, 62.5 ml was sample from the 1 ml of recovery and transferred into a corresponding flask. from those flasks, 1 ml, 10 ml, and 100 ml, were sampled and plated onto lb ampicillin plates. plates and 50 ml culture were incubated at 37˚c overnight. colonies on plates were then counted, and counts were used to calculate how many unique molecules were transformed to gauge number of barcodes. flask with the target number of barcodes was then spun down and midiprepped. cell line description vamp-seq assay cell line hek293t cells with a serine integrase landing pad integrated at the aavs1 locus were used (matreyek et al., 2017) . we used a previously published reporter cell line (haque et al., 2014) and inserted a recombinasebased landing pad at the aavs1 safe harbor locus using a previously published strategy (matreyek et al., 2017) . single cell clones were transfected with talens for aavs1 and the landing pad plasmid, and single cell clones were sorted. presence of one landing pad was confirmed by 1) barcode sequencing of the landing pad and 2) co-transfection experiment with gfp and mcherry. from this, we moved forward with one clone demonstrated to have only one landing pad present (clone 45). grnas to delete portions of the first exon of both vkorc1 and vkorc1l1 were ordered and cloned into pspcas9(bb)à2a-gfp (px458), which was a gift from feng zhang (addgene plasmid #48138; http://n2t.net/addgene:48138; rrid:addgene_48138). clone 45 was then transfected with these four plasmids, and single cells were sorted based on gfp positivity. disruption of vkorc1 and vkorc1l1 was confirmed by performing nested pcr, ta cloning, and then sequencing of products. we detected three alleles for both vkorc1 and vkorc1l1, indicating that these loci are triploid in hek293 cells. a western blot was also used to confirm absence of vkor protein product in our activity reporter cell line. protein lysates were harvested from~1 million cells using 100 ml np40 lysis buffer with freshly prepared protease inhibitor cocktail and 1 mm pmsf. protein lysates were qubited for concentration, and 20 ug of each protein lysate was loaded. 4-12% bistris nupage gel (thermo fisher) was used with mes buffer + 500 ml of antioxidant added to the inner chamber. the gel ran at 150v for 90 min. gel was then transferred to nitrocellulose using 1x transfer buffer 20% etoh at 24v for 1 hr on ice. the blot was washed for 5 min with 1x tbs-t 0.1% tween three times. blot was then blocked for overnight 1x tbs-t 0.1% tween + 5% milk. blot was then washed for 5 min with 1x tbs-t 0.1% tween three times. blot was then cut in half at the between the 25 kda and 35 kda molecular weight markers. the bottom blot was incubated with: avkor 1:1000 + 1x tbs-t 0.1% tween + 5% milk. the top blot was incubated with abeta-actin dhrp 1:1000+ 1x tbs-t 0.1% tween + 5% milk. both blots were incubated with their primary antibodies overnight at 4˚c. the avkor blot was washed for 5 min with 1x tbs-t 0.1% tween three times. the avkor blot was then incubated with 1:10,000 secondary anti-mouse-hrp (ge healthcare na931v) + 1x tbs-t 0.1% tween + 5% milk for one hour. the abeta-actin dhrp blot remained in primary antibody during this time, as no secondary antibody is needed for a direct hrp conjugate. both blots were then washed for 5 min with 1x tbs-t 0.1% tween three times. blots were then incubated with supersignal west dura extended duration substrate (thermo fisher). 500 ml of both substrates incubated on blot for 5 min. blots were then dried by kimwipe and exposed using the colorimetric and chemiluminescence functions on the biorad chemidoc mp (biorad). cells were transfected in six well plates, 250,000 cells per well (12-24 wells transfected total for each experiment). sequential transfections were performed. on day 1, 3 ug of pcag-nls-bxb1 was diluted in 250 ml of optimem and 6 ml of fugene (promega). on day 2, 3 ug of barcoded library was diluted in 250 ml of optimem and 6 ml of fugene6 and transfected. 48 hr after this second transfection, cells were induced with doxycycline at a final concentration of 2.5 ug/ml. cells were transfected in six-well plates, 500,000 cells per well (18-24 wells transfected total for each experiment). 272 ng of pcag-nls-bxb1 was diluted in 125 ul of optimem with 2.7 ug of barcoded library. 2.25 ul of lipofectamine 3000 (thermo fisher) was diluted in 125 ul of optimem in a separate tube. the dna mixture was then added to the lipofectamine 3000 mixture and incubated at room temperature for 15 min. transfection mixture was then added dropwise to one six-well plate. cells were induced with doxycycline 48 hr after transfection, with a final concentration of 2.5 ug/ml doxycycline. cells were washed once with pbs, then dissociated with versene. medium was added to dilute edta, and cells transferred to 15 ml conical and spun down at 300 x g for 4 min. medium was aspirated off, and cells were resuspended in pbs, then filtered through a 35 um nylon mesh filter. cells were sorted on a bd aria iii facs machine. mtagbfp2, expressed from the unrecombined landing pad, was excited with a 405 nm laser. recombined cells either expressed mcherry (abundance) or egfp (activity), and these were excited by a 561 nm laser and a 488 nm laser, respectively. samples were gated for live cells using fsc-a and ssc-a, then singlets using ssc-h vs. ssc-w, fsc-h vs. fsc-w. for activity assay reporter cell line, cells were then sorted for dsred positivity to ensure robust expression of reporter. cells that had successfully recombined a single vkor variant were gated on recombinant mtagbfp2 negativity and either mcherry positivity (abundance) or egfp positivity (activity) (see figure 2 -figure supplement 1b for gating example). recombined cells were sorted on 'yield' mode in the bd diva software and grown out for 3-5 days. recombined cells were run on a bd aria iii facs machine. cells were prepared for sorting as described above, and were then gated for live, recombined singlets. a ratio of egfp/mcherry was created using the bd diva software as a unique parameter, and the histogram of this ratio was divided into four equal bins. each quartile was sorted into a 5 ml tube on '4-way purity' mode. sorted cells were grown out for 2-4 days post sorting to ensure enough dna for sequencing. the details of replicate sorts for activity assay are in supplementary file 1. factor ix gla domain antibody specific for carboxylation was conjugated to apc following lynx rapid apc antibody conjugation kit instructions. antibody was resuspended at 1 mg/ml in nuclease-free water. 1 ml of modifier reagent was then added for every 10 ml of antibody and mixed by pipetting. that mixture was then pipetted directly onto the lynx lyophilized mix and gently mixed by pipetting up and down twice. the conjugation mixture was then capped and incubated in the dark at room temperature overnight. after overnight incubation, 1 ul of quencher reagent was added for every 10 ul of antibody used and left to incubate for 30 min. at that point, antibody was divided into 20 ul aliquots to be used for replicate experiments and stored at à20˚c. cells were plated in six-well plates at 500,000 cells per well with d10 medium with no doxycycline. all replicates were performed with 18-24 wells of cells total. after 24 hr, doxycycline was added to cells to induce expression of reporter and vkor variant. cells were then incubated with doxycycline for 48 hr. on day of cell sorting, each six well was washed with cold pbs, dissociated with 200 ml of versene, and then resuspended in 1 ml of phenol red-free dmem + 1% fbs and transferred to a 5 ml facs tube. cells were spun at 300 x g, then washed once with 1 ml of phenol red-free dmem + 1% fbs. cells were spun at 300 x g, and after aspirating supernatant, cell pellet was resuspended in 100 ul of antibody diluted 1:100 in phenol red-free dmem + 1% fbs. cells were incubated in antibody for 20 min at 4˚c in the dark, with vortexing at five minute intervals to ensure staining. after 20 min, 1 ml of staining buffer was added to each tube to dilute out antibody. cells were spun at 300 x g, washed twice more similarly with staining buffer, then resuspended in 200 ul. at this point, all tubes were pooled and filtered to remove clumps. cells were then sorted using a facsaria iii (bd biosciences) into bins based on their apc intensity. first, live, single, recombinant cells were selected as described above. a histogram of apc was created and gates dividing the library into four equally populated bins based on apc fluorescence intensity were drawn. the details of replicate sorts for activity assay are in supplementary file 2. western blotting for abundance score validation nine variants that spanned the abundance score range were chosen to validate abundance scores. cells were recombined using a selectable serine integrase landing pad (matreyek et al., 2020 ) using the transfection method described above for abundance experiments. recombinants were then selected with a small molecule, ap1903, at a concentration of 10 nm. protein lysates were harvested from~1 million cells using 100 ml np40 lysis buffer with freshly prepared protease inhibitor cocktail. 15 ml of each protein lysate was loaded onto a 4-12% bistris nupage gel (thermo fisher) with mes buffer + 500 ml of antioxidant added to the inner chamber. the gel ran at 200v for 35 min. gel was then transferred to nitrocellulose using 1x transfer buffer 10% metoh at 24v for 1 hr on ice. the blot was washed for 5 min with 1x tbs three times. blot was then blocked for one hour with 1x tbs-t + 5% milk and then washed for 5 min with 1x tbs-t 0.1% tween three times. the blot was incubated with avkor 1:1000 and acofilin 1:1000+ 1x tbs-t 0.1% tween + 5% milk overnight at 4c . the blot was washed for 5 min with 1x tbs-t 0.1% tween three times. the blot was then incubated with 1:10,000 goat anti-mouse igg (h+l) highly cross-adsorbed secondary antibody, alexa fluor plus 488 (thermofisher) and 1:10,000 goat anti-rabbit igg (h+l) cross-adsorbed secondary antibody, alexa fluor 647 (thermofisher)+ 1x tbs-t 0.1% tween + 5% milk for one hour. the blot was then washed for 5 min with 1x tbs-t 0.1% tween three times. the blot was then imaged using the alexafluor488 and alexafluor647 fluorescent channels on the chemidoc mp (biorad). cells were then collected, pelleted by centrifugation and stored at à20˚c. genomic dna was prepared using a dneasy kit, according to the manufacturer's instructions (qiagen), with the addition of a 30 min incubation at 37˚c with rnase in the re-suspension step. eight 50 ml first-round pcr reactions were each prepared with a final concentration of~50 ng mlàone input genomic dna, 1 â q5 high-fidelity master mix and 0.25 mm of the kam499/vkorampr 1.1 primers. the reaction conditions were 98˚c for 30 s, 98˚c for 10 s, 65˚c for 20 s, 72˚c for 60 s, repeat five times, 72˚c for 2 min, 4˚c hold. eight 50 ml reactions were combined, bound to ampure xp (beckman coulter), cleaned and eluted with 21 ml water. forty percent of the eluted volume was mixed with q5 high-fidelity master mix; vkor_indexf_1.1 and one of the indexed reverse primers, pten_seq_r1a through pten_seq_r2a, were added at 0.25 mm each. these reactions were run with sybr green i on a bio-rad miniopticon; reactions were denatured for 3 min at 95˚c and cycled 20 times at 95˚c for 15 s, 60˚c for 15 s, 72˚c for 15 s with a final 3 min extension at 72˚c. the indexed amplicons were mixed based in relative fluorescence units and run on a 1% agarose gel with sybr safe and gel extracted using a freeze and squeeze column (bio-rad). the product was quantified using kapa illumina quant kit. barcoded vkor library was subassembled using a miseq 600 kit (illumina). two amplicons were generated, one forward, one reverse. pcr reactions were each prepared with~500 ng input plasmid dna, 1 â kapa high-fidelity master mix and 0.25 mm of the vkor_sa_amp_f/vkor_sa_amp_r or vkor_sa_for_amp_r2.0/vkor_sa_rev_amp_f2.0 primers. pcr reactions were run at 95˚c for five minutes, then cycled 15 times at 98˚c for 0:20, 60˚c for 0:15, 72˚c for 0:30, with a final extension at 72˚c for 2:00. amplicons (741 bp) were gel extracted on a 1.0% gel run at 130v for 35 mins. the product was quantified using qubit and kapa illumina quant kit. read lengths were as follows: 289 bp forward read, 18 bp index1, 18 bp index 2 (index = barcode forward and reverse). all reads sharing a common barcode sequence were collapsed to form the consensus variant sequence, resulting in 175,052 barcodes after filtering. enrich2 was used to quantify barcodes from bin sequencing, using a minimum quality filter of 20 (rubin et al., 2017) . fastq files containing barcodes and the barcode map for vkor were used as input for enrich2. enrich2 configuration files for each experiment are available on the github repository. barcodes assigned to variants containing insertion, deletions, or multiple amino-acid alterations were removed from the analysis. scores and classifications were assigned using previously published analysis pipeline (matreyek et al., 2018) . briefly, for each protein variant, frequencies in each bin were calculated by dividing counts by total counts. from there, we filtered variants based on the number of experiments in which it was observed (f expt = 2) and their frequency (f freq = 10 à4 ), after noticing that low frequency variants introduced noise to the analysis. these frequencies were then each weighted by multiplying by 0.25, 0.5, 0.75, and one in a bin-wise fashion. we generated a replicate score for each variant by using min-max normalization: normalizing to the median weighted average of the nonsense distribution set at 0 and the median weighted average of the synonymous distribution set at 1. we then averaged those scores for a final, experiment-wide variant score. standard deviation and standard error were also calculated for each variant, and 95% confidence intervals were estimated using standard error, assuming a normal distribution. abundance and activity classifications were assigned by assessing variant score and confidence intervals in relation to synonymous variant distribution. to do this, we established a cut-off that separated the 5% of synonymous variants with the lowest abundance (or activity) scores from the 95% of synonymous variants with higher abundance (or activity) scores. variants with both scores and upper confidence intervals below this threshold were classified as 'low,' while those with scores below but upper confidence above were classified as 'possibly low.' variants with scores and lower confidence intervals above the threshold were classified as 'wt-like', while those with scores above lower confidence intervals below the threshold were classified as 'possibly wt-like.' finally, another threshold was set that separated the 5% of synonymous variants with the highest scores from the rest of the synonymous distribution. variants that had scores above this threshold, with lower confidence intervals above the lower threshold were classified as 'high'. windowed averages of abundance and activity scores were calculated using a window length of 10 positions with center alignment. scores were calculated for both charged amino acids (r, k, h, d, e,) and aliphatic amino acids (g, a, v, i, l). evcouplings extracts the constraints between pairs of residues, as evidenced in alignments of homologous sequences: first homologous sequences must be collected and aligned, and then a model of statistical energy costs and benefits between residues is fit to explain the sequence variation in the alignment. we collected an alignment of 2770 sequences using jackhammer (http:// hmmer.org/) to query the human vkor sequence against uniref100 (https://www.uniprot.org/uniref/), with a bitscore per residue cutoffs of 0.4 and 7 search iterations. we predicted secondary structures where the summed strength of couplings at would-be alpha helix and beta strand contacts scored above 1.5 for alpha helices and 0.75 respectively, for two or more consecutive residues. we extended the called helices and strands by one residue on each side for a minimum structure size of four residues. all methods used for building alignments, training the model, folding, and predicting secondary structure are part of the evcouplings software (https://evcouplings.org/) (hopf et al., 2019) . a homology model of human vkor was made by accessing i-tasser (yang et al., 2015) and using pdb structure 4nv5 as a template for threading. model1 from results was used for all figures in this paper. hierarchical clustering was performed on abundance score vectors for each position using the hclust function in r. dendrogram for hierarchically clustered heatmap was drawn using dendextend package (version 1.12.0). activity and abundance scores were rescaled so that the lowest score present in the dataset was set at 0, and the highest score at 1. a ratio of rescaled activity to rescaled abundance (specific activity) was then calculated for every variant. using variant specific activity scores, median specific activity was calculated for each position. threshold for classification as an active site position was drawn based on scores of known redox cysteines at positions 132 and 135, resulting in lowest 12.5% of median specific activity scores being classified as active site residues. we additionally required that any position within this group had been scored for at least four variants to eliminate noise from poor sampling. code for analysis is available at http://github.com/fowlerlab/vkor (chiasson, 2020a ; copy archived at https://github.com/elifesciences-publications/vkor). the code used to train the evolutionary couplings model is available at the evcouplings github repository (chiasson, 2020b ; https://github.com/debbiemarkslab/evcouplings; copy archived at https://github.com/elifesciences-publications/evcouplings). the data used to train the model is publically available at uniprot (https://uniprot.org). vkor abundance and activity score analysis. github. f80bb91 the arg98trp mutation in human vkorc1 causing vkcfd2 disrupts a di-arginine-based er retention motif warfarin and vitamin k compete for binding to phe55 in human vkor mutational scanning reveals the determinants of protein insertion and association energetics in the plasma membrane interplay between hydrophobicity and the positive-inside rule in determining membrane-protein topology specificity in transmembrane helix-helix interactions can define a hierarchy of stability for sequence variants the power of multiplexed functional analysis of genetic variants enzymatic assembly of dna molecules up to several hundred kilobases clinical and genetic determinants of warfarin pharmacokinetics and pharmacodynamics during treatment initiation analysis of large-scale mutagenesis data to assess the impact of single amino acid substitutions transmembrane helix hydrophobicity is an energetic barrier during the retrotranslocation of integral membrane erad substrates r-vkorc1 expression in factor ix bhk cells increases the extent of factor ix carboxylation but is limited by saturation of another carboxylation component or by a shift in the rate-limiting step a cellular system for quantitation of vitamin k cycle activity: structure-activity effects on vitamin k antagonism by warfarin metabolites altered escherichia coli membrane protein assembly machinery allows proper membrane assembly of eukaryotic protein vitamin k epoxide reductase recognition of transmembrane helices by the endoplasmic reticulum translocon molecular code for transmembrane-helix recognition by the sec61 translocon protein targeting and degradation are coupled for elimination of mislocalized proteins three-dimensional structures of membrane proteins from genomic sequencing the evcouplings python framework for coevolutionary sequence analysis a rapid, efficient, and economical inverse polymerase chain reaction-based method for generating a site saturation mutant library dictionary of protein secondary structure: pattern recognition of hydrogen-bonded and geometrical features variation across human exomes and genomes reveals the spectrum of loss-of-function intolerance across human protein-coding genes effect of the vkorc1 d36y variant on warfarin dose requirement and pharmacogenetic dose prediction clinvar: public archive of relationships among sequence variation and human phenotype identification of the gene for vitamin k epoxide reductase structure of a bacterial homologue of vitamin k epoxide reductase structures of an intramembrane vitamin k epoxide reductase homolog reveal control mechanisms for electron transfer rules for the recognition of dilysine retrieval motifs by coatomer protein 3d structure computed from evolutionary sequence variation a platform for functional assessment of large variant libraries in mammalian cells multiplex assessment of protein variant abundance by massively parallel sequencing an improved platform for functional assessment of large protein libraries in mammalian cells substratemodulated unwinding of transmembrane helices in the nss transporter leut packing of apolar side chains enables accurate design of highly stable membrane proteins fine-tuning the topology of a polytopic membrane protein: role of positively and negatively charged amino acids mutations in the vkorc1 gene cause warfarin resistance, warfarin sensitivity and combined deficiency of vitamin k dependent coagulation factors an algorithm for managing warfarin resistance vkorc1 pharmacogenomics summary novel insight into the mechanism of the vitamin k oxidoreductase (vkor): electron relay through cys43 and cys51 reduces vkor to allow vitamin k reduction and facilitation of vitamin k-dependent protein carboxylation mutations in vkorc1 cause warfarin resistance and multiple coagulation factor deficiency type 2 a statistical framework for analyzing deep mutational scanning data vitamin k epoxide reductase prefers er membrane-anchored thioredoxin-like redox partners a comprehensive comparison of transmembrane domains reveals organelle-specific properties warfarin traps human vitamin k epoxide reductase in an intermediate state during electron transfer stabilization of warfarin-binding pocket of vkorc1 and vkorl1 by a peripheral region determines their different sensitivity to warfarin inhibition alignme-a membrane protein sequence alignment web server human vitamin k epoxide reductase and its bacterial homologue have different membrane topologies and reaction mechanisms evaluation of warfarin resistance using transcription activator-like effector nucleases-mediated vitamin k epoxide reductase knockout hek293 cells structured states of disordered proteins from genomic sequences a series of pdb-related databanks for everyday needs amino acid distributions in integral membrane protein structures control of topology and mode of assembly of a polytopic membrane protein by positively charged residues warfarin and vitamin k epoxide reductase: a molecular accounting for observed inhibition the i-tasser suite: protein structure and function prediction a novel functional vkorc1 promoter polymorphism is associated with inter-individual and interethnic differences in warfarin sensitivity biochemical basis of hereditary resistance to warfarin in the rat we thank d nickerson and m dunham for helpful conversations in analyzing the data and writing the manuscript, a leith of the uw foege flow lab and d prunkard of the uw pathology flow cytometry core facility for assistance with cell sorting, and all members of the fowler lab for helpful feedback on figures. this work was supported by the nih (r24gm115277 p01gm116691 the funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. melissa a chiasson, conceptualization, data curation, formal analysis, supervision, funding acquisition, validation, investigation, visualization, methodology, writing -original draft, writing -review and editing, carried out abundance and activity experiments and analyzed the data, wrote the manuscript with input from co-authors; nathan j rollins, debora s marks, conceptualization, formal analysis, supervision, validation, performed evolutionary couplings analysis; jason j stephany, methodology, prepared samples for next-generation sequencing; katherine a sitko, validation, cloned variants for abundance assay validation; kenneth a matreyek, conceptualization, provided abundance analysis framework; marta verby, song sun, frederick p roth, resources, provided a mutagenized vkor library; daniel desloover, data curation, writing -review and editing, provided human vkorc1 variants from color genomics; allan e rettie, conceptualization, resources, provided the parental activity reporter cell line; douglas m fowler, conceptualization, supervision, funding acquisition, writing -review and editing, wrote the manuscript with input from co-authors key: cord-016575-bn15006x authors: cox-georgian, destinney; ramadoss, niveditha; dona, chathu; basu, chhandak title: therapeutic and medicinal uses of terpenes date: 2019-11-12 journal: medicinal plants doi: 10.1007/978-3-030-31269-5_15 sha: doc_id: 16575 cord_uid: bn15006x terpenes, also known as terpenoids are the largest and most diverse group of naturally occurring compounds. based on the number of isoprene units they have, they are classified as mono, di, tri, tetra, and sesquiterpenes. they are mostly found in plants and form the major constituent of essential oils from plants. among the natural products that provide medical benefits for an organism, terpenes play a major and variety of roles. the common plant sources of terpenes are tea, thyme, cannabis, spanish sage, and citrus fruits (e.g., lemon, orange, mandarin). terpenes have a wide range of medicinal uses among which antiplasmodial activity is notable as its mechanism of action is similar to the popular antimalarial drug in use—chloroquine. monoterpenes specifically are widely studied for their antiviral property. with growing incidents of cancer and diabetes in modern world, terpenes also have the potential to serve as anticancer and antidiabetic reagents. along with these properties, terpenes also allow for flexibility in route of administration and suppression of side effects. certain terpenes were widely used in natural folk medicine. one such terpene is curcumin which holds anti-inflammatory, antioxidant, anticancer, antiseptic, antiplasmodial, astringent, digestive, diuretic, and many other properties. curcumin has also become a recent trend in healthy foods and open doors for several medical researches. this chapter summarizes the various terpenes, their sources, medicinal properties, mechanism of action, and the recent studies that are underway for designing terpenes as a lead molecule in the modern medicine. terpenes, also known as isoprenoids are the largest and most diverse group of naturally occurring compounds that are mostly found in plants but larger classes of terpenes such as sterols and squalene can be found in animals. they are responsible for the fragrance, taste, and pigment of plants. 1 terpenes are classified on the basis of organization and number of isoprene units it contains (see footnote 1). an isoprene unit is a building block of terpenes that is a gaseous hydrocarbon that contains the molecular formula c 5 h 8 (see footnote 1). terpenes and terpenoids are terms that are often used interchangeably but the two terms have slight differences; terpenes are an arrangement of isoprene units that are naturally occurring, volatile, unsaturated 5-carbon cyclic compounds that give off a scent or a taste to defend itself from organisms that feed off of certain types of plants (see footnote 1). terpenes have many functions in plants such as a thermoprotectant, signaling functions, and not limited to, pigments, flavoring, and solvents but also have various medicinal uses (yang et al. 2012) . table 15 .1 shows the different types of terpenes discussed in this chapter along with an example of that terpene. terpene is a natural compound with various medical properties and found in both plants and animals (gershenzon 2007) . among natural products that mediate antagonistic and beneficial interactions within the organism, terpene play a variety of roles (gershenzon 2007) . terpene protects many living organisms like microorganisms, animals and plants from abiotic and biotic stresses (gershenzon 2007) . terpene can ward off pathogens, predators, and competitors. living organisms use terpene for multiple reasons like medicinal purposes and communications about food, mates, or enemies (gershenzon 2007) . it is impressive how different organisms use terpene for common purposes even though terpene contain many forms and varieties (gershenzon 2007) . so far only a small percentage of terpene is investigated (franklin et al. 2001 ). cannabis is one of the most common sources for the medicinal terpene (franklin et al. 2001 ). this plant contains many medicinal properties like anticancer, antimicrobial, antifungal, antiviral, antihyperglycemic, analgesic, anti-inflammatory, and antiparasitic (franklin et al. 2001) . terpene is also used to enhance skin penetration, prevent inflammatory diseases (franklin et al. 2001) . nowadays modern medication use large scales of terpene for various treatment drugs (franklin et al. 2001) . there are commonly used plants like tea (melaleuca alternifolia), thyme, cannabis, salvia lavandulifolia (spanish sage), citrus fruits (lemon, orange, mandarin) etc. that provide wide range of medicinal values (perry et al. 2000) . tea tree oil has increased in popularity in recent years when it comes to alternative medicine (perry et al. 2000) . tea tree oil is a volatile essential oil and is famous for its antimicrobial properties, and acts as the active ingredient that is used to treat cutaneous infections (carson et al. 2006 ) apart from the flavor that gives to food, essential oil contain antimicrobial properties (bound et al. 2015) . thyme is one of plants that synthesize terpene alcohols and phenols which contain powerful antibacterial and antifungal properties (bound et al. 2015) . terpene synthesized from cannabis also long served as medicines (perry et al. 2000) . they also contain psychoactive properties and used against many infectious diseases (perry et al. 2000) . salvia lavandulifolia is famous for anti-dementia (current memory-enhancing) drugs by enhancing james and dubery (2009) cholinergic activity via inhibition of cholinesterase (perry et al. 2000) . in vitro examination method was used to study the effects of constituent terpenes on human erythrocyte acetylcholinesterase (perry et al. 2000) . some of the medicinal properties of terpenes are listed in table 15 .2. important properties associated with terpene are difficult to overstress (franklin et al. 2001 ). there are many important uses with terpene and these include antiinsect properties, antimicrobial properties and anti-herbivore properties (franklin et al. 2001) . terpene can be extracted through plants and thorough some insects (franklin et al. 2001) . without using harsh chemicals that could potentially contain side effects, terpene is a healthy alternative to ward off insects (franklin et al. 2001 ). there have been many pesticides made for killing domestic pests like lice, or mites (franklin et al. 2001) . in these cases, it is very important to make sure that these pesticides do not affect humans in harmful ways (franklin et al. 2001 ). there are many options like shampoo, sprays, lotions that were manufactured against pests that include one or more terpenes that are employed in the instant invention (franklin et al. 2001 ). these naturally occurring terpenes are generally not modified they were used in their raw form and the environment protection agency in the usa classified as "gras" which mean generally regards as safe (franklin et al. 2001 ). certain terpene is highly effective against both lice and lice eggs and there is a less than significant chance of resistance developing against this terpene based pesticides; reason for this is their observed modes of action (franklin et al. 2001 ). silva et al. (2008) unlike other types of pediculosis medication this terpene based instant inventions are not neurotoxins (franklin et al. 2001) terpenes are also used combined with terpene aldehyde called citral. citral derives from an essential oil that is extracted from lemongrass (cymbopogon citratus) (franklin et al. 2001) . citral possesses antibacterial and antifungal properties, while lemongrass possesses anti-insect properties (franklin et al. 2001) . a series of anti-insect formulation contain many terpenes (franklin et al. 2001 ) most of these pesticides are a mix of terpene and citral (franklin et al. 2001 ). table 15 .3 consists of what these terpenes include. antimicrobial properties or the ability to kill or stop growth of a microorganism in terpenes are commonly used in traditional and modern medicine (himejima et al. 1992 ). there are many terpenes with antimicrobial activities (himejima et al. 1992 ). the following plants produce terpenes which have antimicrobial properties: pinus ponderosa (pinaceae), spices (sage, rosemary, caraway, cumin, clove, and thyme), cretan propolis, helichrysum italicum, rosmarinus officinalis, and so on (himejima et al. 1992) . these antimicrobial terpenes can also be used against food borne pathogen like escherichia coli, staphylococcus aureus, and bacillus cereus (himejima et al. 1992) . pinus ponderosa cell extract contain wide-ranging antimicrobial activities (himejima et al. 1992) . after steaming and distillation from pinus ponderosa cell extract, a distillate and a residue are obtained (himejima et al. 1992) . the distillate consists of monoterpenes and some sesquiterpenes while the residue consists of four diterpene acids (himejima et al. 1992) . it was also reported that when a physical damage is caused to the pine tree or any other terpene containing tree from insect attacks, resin which contains terpene secret to protect the tree from further damage (himejima et al. 1992) . five different kinds of terpene can be isolated from cretan propolis, they are, the diterpenes, 14,15-dinor-13-oxo-8(17)-labden-19-oic acid and a mixture of labda-8(17),13e-dien-19-carboxy-15-yl oleate, palmitate and triterpene (popova et al. 2009 ). spectroscopic analysis and chemical evidence has been used to establish the structures of the different compounds (popova et al. 2009 ). these compounds that were isolated from terpene was tested for its antimicrobial activity against bacteria like gram positive and gram negative (popova et al. 2009 ). it was all tested for human pathogenic fungi which has broad-spectrum antimicrobial activity (popova et al. 2009 ). helichrysum italicum essential oil was analyzed using gas chromatography and mass spectrometry to fraction into terpene and terpenoid. fifty two compounds, including hydrocarbons of the oil; α-pinene (10.2%), α-cedrene (9.6%) aromadendrene (4.4%), β-caryophyllene (4.2%), and limonene (3.8%), neryl acetate (11.5%), 2-methylcyclohexyl pentanoate (8.3%), 2-methylcyclohexyl octanoate (4.8%), and geranyl acetate (4.7%) were identified (mastelic et al. 2017 ). the smallest of terpenes are monoterpenes. they contain the compound c 10 h 16 , come from different flowers, fruits and leaves and are known as the main component of essential oils, fragrances and many structural isomers (see footnote 1). monoterpenes are also the most fragrant of all the classes of terpenes (see footnote 1). examples for the types of monoterpenes found in natural scents are α-pinene, which imparts scent to pine trees, and limonene from citrus plants (see footnote 1). what is thought to be one of the main purposes of monoterpenes is to attract pollinators or to serve the purpose of repelling other organisms from feeding off of plants. they also may be related to the flowering process of the plants (loreto et al. 2002) . they are isolated from their plant sources by distillation with steam and have a boiling points in the range of 150 °c to 185 °c (see footnote 1). monoterpenes are purified using fractional distillation at pressures that are reduced or use another process in order to form a crystalline derivative (see footnote 1). many studies test the hypothesis of high emissions of monoterpenes under high temperatures using the leaves of quercus ilex, also known as evergreen oak (table 15 .1). the evergreen tree is native to the mediterranean area where it has to survive under hot and dry conditions and synthesis of these monoterpenes may have been an adaptive mechanism for the plants to survive under heat stress. 2 this tree does not emit isoprenes but it emits monoterpenes and is able to handle different environmental stresses such as drought, salt, and heat (see footnote 2). a particular study done by loreto et al. (2002) were conducted to visualize monoterpene production in response to high temperatures and to see if thermotolerance is increased with monoterpenes (loreto et al. 2002) . in this study, the leaves were exposed in 5 °c intervals ranging from the temperatures 30 °c to 55 °c and leaves were kept under conditions in which inhibited or allowed monoterpenes to synthesize (loreto et al. 2002) . the results that were found in this experience was a discovery of seven most abundant monoterpenes which was emitted at the maximum temperature of 35 °c and decreased its abundance over time as the temperatures increased and α-pinene had the greatest abundance of emittance at 35 °c as well as other terpenes but greatly reduced over higher temperatures (loreto et al. 2002) . at 55 °c the monoterpenes, myrcene and limonene had higher emission rates compared to temperatures around 35 °c (loreto et al. 2002) . photosynthesis was also decreased when the leaves were exposed to any temperature that was higher than 30 °c and at 55 °c showed a loss of co 2 and recovery occurred around 30 °c (loreto et al. 2002) . overall, the monoterpenes showed that their optimal temperature for emission was around 30-35 °c (loreto et al. 2002) . researchers prove that the emission of monoterpenes is under enzymatic control due to their optimal temperatures (loreto et al. 2002) . sesquiterpenes, containing the chemical formula c 15 h 24 , are much larger compounds than monoterpenes and are much more stable in comparison. 3 they are isolated by distillation with steam or by extraction and purified by methods such as vacuum fractional distillation or gas chromatography (see footnote 1). oxidation or rearrangement of isoprene units that are made to sesquiterpenes produce the corresponding sesquiterpenoids (see footnote 1). sesquiterpenes are naturally occurring and found in plants, fungi, and insects and act as a defensive mechanism or attract mates with pheromones in insects (see footnote 1). acyclic compounds of sesquiterpenes such as farnesans can be used as a natural pesticide for insects and also as pheromones for some insects and mammals such as elephants, to attract mates or to mark their territory (see footnote 1). sesquiterpenes have a vital role in plant growth hormones and signaling properties in response to its environment (giraudat 1995) . abscisic acid has a role in plants such as development, germination, cell division, and synthesis of protein storage and signalling (giraudat 1995) . it also plays a role in plants in response to various environmental stresses. it regulates the closure of the stoma by regulating ion channels and exchange of water across the plasma membrane (giraudat 1995) . cyclic adp-ribose signals abscisic acid in response to drought-stressing conditions from the environment (giraudat 1995) . abscisic acid is not unique to plants, it has shown to be present in the central nervous system of other organisms such as pigs and may play a role in humans as a pro-inflammatory cytokine and stimulator of insulin release in the human pancreas (chadwick et al. 2013) . gossypol is a sesquiterpene that is found in cotton plants. it has anticancer properties and can potentially inhibit fertility in male humans which is why it must be removed from essential oils and various other products before human use or consumption. avarol, a sesquiterpenoid that has shown to have antimicrobial and antifungal uses, is effective against the aids virus in humans (see footnote 3). 4 the medicinal properties of sesquiterpenes typically come from flowering plants that are included in the asteraceae family, which include, but not limited to sunflowers, marigolds, and daisies. this family of flowers is a significant resource for potent sesquiterpene lactones, which are usually found in the leaves and the flower portion of plants and are constantly being produced at high levels (chadwick et al. 2013) . the role of sesquiterpenes in these flowering plants are not solely made for human use but for the purpose of protecting the plant from predators and are produced de novo in response to microbial attack and ultraviolet ray protection (chadwick et al. 2013) . their bitter taste is a defense mechanism against herbivores from feeding on them but some have sweet tastes or tastes that are pleasant to certain organism for the purpose of spreading their seeds and being fertilized in different areas (chadwick et al. 2013) . sesquiterpenes have many uses in traditional, western medicine because they contain so many anticancer, antiplasmodial, and anti-inflammatory activities (chadwick et al. 2013) . sesquiterpenes lactones are able to reduce stomach ulcers in some people and are also present in powerful antimalarial drugs (chadwick et al. 2013 ). artemisinin, a metabolite produced from artemisia annua, which contains sesquiterpene lactone produced in the roots and shoots of the plants, is used in drugs to treat malaria (chadwick et al. 2013) . other uses of this family of flowers is for treatment of bacterial infections, migraines, and to improve skin (chadwick et al. 2013) . lettuce opium has been used for many years as a painkiller (chadwick et al. 2013 ). diterpenes are naturally occurring chemical compounds that contain the molecular formula, c 20 h 32 . diterpenes have physiologically active groups such as vitamin a activity well as plant growth hormones that regulate germination, flowering and switch reproductive cycles (from asexual to sexual reproduction) of plants (lee et al. 2015) . they can also be classified as a phytol, which is an oxygenated acyclic diterpene. over 650 diterpenoids have been isolated from euphorbia plants, which is a very diverse genus of flowering plants (popova et al. 2009 ). diterpenes have many therapeutic benefits such as antitumor, cytotoxic, and anti-inflammatory (vasas and hohmann 2014) . they are present in anticancer drugs such as taxol, and the tumor promoter, phorbol (vasas and hohmann 2014) . tanshinones are a class of diterpenes that are isolated from dried roots or rhizomes of an herb in traditional chinese medicine called salvia miltiorrhiza also known as danshen or tanshen (zhang et al. 2012) . tanshinones were first isolated in the 1930s, and since then, more than 90 chemicals have been identified and split up into two groups: 40 lipophilic and 50 hydrophilic compounds (zhang et al. 2012) . tanshinones have recently been extensively researched for their anticancer properties in vitro and in vivo (zhang et al. 2012 ). their potential use as an anticancer drug comes from their broad range of activities such as anti-proliferation and inhibiting adhesion, migration, and invasion (zhang et al. 2012) . analogues of tanshinone have been synthesized in many clinical trials because they have many anticancer attributes (lee et al. 2015) . this herb has been used in many asian countries for preventative and therapeutic solutions to many diseases such as heart disease, vascular diseases, and arthritis (zhang et al. 2012) . tanshinones may also reduce inflammation and increase immune responses (zhang et al. 2012) . cafestol and kahweol are diterpene alcohols that are found in the oil derived from coffee beans. these chemical structures are very similar but only differ by an extra double bond that is present in kahweol's chemical structure. 5 researchers have reported that coffee lowers the risk of depression in women, prostate cancer in men, stroke, diabetes, and some cancers (see footnote 5). it is thought that the antiinflammatory and antioxidant properties of these particular diterpenes are responsible for such events (see footnote 5). coffee benefits the liver as well by lowering liver enzymes that are in response to inflammation and damage and may offer some protection against liver cancer as well (see footnote 5). the adverse result of these diterpenes is that they raise cholesterol level, but it seems to be limited to coffee that has been unfiltered and has oily droplets of cafestol and kahweol (see footnote 5). filtered coffee may not have much impact on cholesterol levels (see footnote 5). triterpenes are composed of three or six isoprene units and have the chemical formula c 30 h 48 which includes steroids and sterols with squalene being the biological precursor of all triterpenes (see footnote 1). triterpenes are produced by animals, plants, and fungi. they play a role as precursors to steroids in animal and plant organisms, and are derived from mevalonic acid (see footnote 1). saponins come from the skins of many plants and have emulsion like properties that make them excellent detergents in the human digestive system (see footnote 1). chemical structures of steroid saponins are similar to hormones that are produced in the human body (see footnote 1). the medicinal uses of triterpenes are not quite as recognized as other different types of terpenes but their uses are being continuously investigated by researchers. their properties have been studied for anticancer, antioxidant, antiviral, and anti-atherosclerotic activities (nazaruk and borzym-kluczyk 2015) . some studies have shown that there is promising potential for the use of triterpenes for people with diabetes by aiming to reduce glucose levels and also by reducing sweetness inhibitors in sweet and high calorie foods (nazaruk and borzym-kluczyk 2015) . saponins have detoxification properties and act as a diuretic for the kidneys and wound healing properties (nazaruk and borzym-kluczyk 2015) . tetraterpenes are also known as carotenoids that have the molecular formula c 40 h 56 and can be in the category of terpenes because they are made from isoprene units. 6 most carotenoids are highly unsaturated and for this reason, they are extremely difficult to isolate and purify (see footnote 1). they are found in all different types of fungi, bacteria, and plants and mainly responsible for red, yellow, or orange fatsoluble plant and animal pigments (see footnote 6). one of the most crucial and common tetraterpene is beta-carotene that contributes to the yellow pigment in carrots. it is important to mammals especially because it is a precursor in producing vitamin a and other important terpenoids for vision (see footnote 1). higher order terpenes have been shown to increase thermotolerance (singsaas 2001) . the permeability of the thylakoid membranes increase at higher temperatures and this happens by an increase in cyclic photophosphorylation around photosystem ii (singsaas 2001) . when the temperature of the atmosphere continues to rise, the photophosphorylation system is not able to keep up with protons leaking, which causes the transmembrane gradient to drop and a reduction in atp synthesis occurs (singsaas 2001) . all these events can potentially cause lowering in the rubisco activation state due to an inhibition of rubp regeneration (singsaas 2001) . the mep pathway, also known as the non-mevalonate pathway or methylerythritol phosphate pathway, is a metabolic pathway for isoprenoid biosynthesis that creates the products isopentenyl pyrophosphate (ipp) and dimethylallyl pyrophosphate (dmapp). this pathway occurs in the chloroplasts and produce monoterpenes, specific sesquiterpenes, diterpenes, and carotenoids (zhang et al. 2012) . the vital application of this pathway is to develop antimicrobial agents to target diseases such as malaria and sexually transmitted diseases (hunter 2007) . since this pathway does not occur in humans, it is a valuable resource to develop antibacterial and antiparasitic drugs (seemann et al. 2009 ). the first steps of this pathway involve pyruvate and d-glyceraldehyde 3-phosphate to produce doxp which is catalyzed by 1-deoxy-d-xylulose-5-phosphate (dxs) (hunter 2007) . 1-deoxy-d-xylulose-5-phosphate reductoisomerase, otherwise known as ispc, coverts doxp to mep. from mep, it reacts with ctp to create 4-diphosphocytidyl-2c-methyl-d-erythritol (hunter 2007) . a phosphate is released in this reaction and then reacts with atp-dependent ispe to make 4-dipho sphocytidyl-2c-methyl-d-erythritol 2-phosphate and adp and then reacts with the enzyme ispf to create 2c-methyl-d-erythritol 2,4-cyclodophosphate (hunter 2007) . the enzyme requires metal cations. then finally, in the least understood step of the reaction, the two enzymes, ispg and isph make the two products, ipp and dmapp by using a two-electron reduction (hunter 2007) . the pathway is regulated by control of repression or activation of gene expression via feedback loops within the pathway or by effector molecules which target an enzyme or downstream activities (hunter 2007) . the mva pathway or mevalonic acid pathway occurs in the cytosol. it is responsible for the synthesis of sterols, specific sesquiterpenes, and also may play a role in the synthesis of transhinones (zhang et al. 2012) . in gram-positive bacteria, the genes in the metabolic pathways such as mva are organized into operons and are thought to be regulated by transcription (hunter 2007) . the use of cannabis is increasing for medicinal uses that commonly treat pain, the side effects of chemotherapy in cancer patients such as nausea, anxiety and depression, and its uses and benefits are continuously being researched by scientists (cathcart et al. 2015) . there are at least 80 compounds that come from the cannabis plant that are regarded as cannabinoids that cause psychotropic effects in the human brain due to cb 1 receptors (klein et al. 2011) . the main active ingredient, delta-9tetrahydrocannabinol, otherwise known as thc, is a psychoactive agent and is a focus for controversy in society because it binds to the human endocannabinoid receptors in areas of the brain such as the hippocampus and the frontal cortex, which are responsible for memory, cognition and attention. 7 how thc works is by taking the place of endocannabinoids, naturally occurring chemicals in the human body (see footnote 7). one of the most common and well known molecules that thc replaces in the human body is called anadamide (see footnote 7). to this day, scientists are researching to discover the exact role of this molecule in the human body. cannabidiol, or cbd is also a common ingredient in cannabis but compared to thc, it is a non-psychoactive and it can potentially reduce the effects of thc (klein et al. 2011 ). cbd does not bind to the same receptors as thc does in the human body and it works by inhibiting faah or the enzyme fatty acid amide hydroxyls (see footnote 7). this enzyme is responsible for degrading anadamide in the body and by inhibiting faah, cbd increases natural endocannabinoids already in the human system (klein et al. 2011) . cbd is thus an agent that works for depression, anxiety and neuroprotective effects (klein et al. 2011) . what are major components in cannabis are the monoterpenes that are responsible for many different medicinal properties. one of the main uses for thc is the potential for cancer treatment and can play a role in reducing size of tumors (see footnote 7). thc can also reduce inflammation caused by certain diseases in patients. other conditions that thc can help but are not limited to are adhd, arthritis, migraines, and glaucoma (see footnote 7). 8 it can also improve the symptoms in individuals that suffer from hiv by helping their appetite and thus causing weight again, improving their depression symptoms and their quality of life (lutge et al. 2013 ). terpenes have been shown to have a favorable antiplasmodial activity. with the rising malarial infections and drug resistance, terpenes have gained more attention towards it through antiplasmodial activity (nogueira and lopes 2011) . the interesting mechanism behind the terpene activity is that it binds to the hemin part of infected erythrocytes and kills the parasite just like the famous antimalarial drug chloroquine (orjih et al. 1981; kayembe et al. 2012) . hemin is made of iron which is necessary for the plasmodium development in the erythrocytes. though hemin breaking enzymes are not yet found in plasmodium, it could be one reason why hemin binding accounts for parasite lysis (ginsburg and demel 1984) . another study suggests that drug-hemin complex binds to phospholipid layers thereby disrupting the respective membrane structure and causing cell lysis (ginsburg and demel 1984) . moreover, it is also known that hemin can affect the carbohydrate metabolism of the parasites, which could lead to lysis of parasites (rodriguez and jungery 1986) . thus, terpenes can be designed to be promising drugs for malaria. different kinds of terpenes show different effects on the parasites. for instance, beta-myrcene the most common terpenes, is proven to have in vitro antiplasmodial activity (kpoviessi et al. 2014 ). beta-myrcene from cannabis sativa, the plant which is high in terpenes, does not show an anti plasmodial effect but extracts from stem, leaves, and seeds of clove basil showed a good antiplasmodial activity (small 2017; kpoviessi et al. 2014 ). additionally, it was also reported to have antitrypanosomal activity when tested against trypanosoma brucei brucei (habila et al. 2010) . this data leads to the fact that terpenes are effective against pathogenic protista. limonene regarded as the second most commonly found terpene, also possesses antiplasmodial activity against plasmodium falciparum. limonene achieves its goal by targeting the intermediates of the active isoprenoid pathway of the parasite. isoprenoid pathway plays a major role in parasite survival by mediating cell signaling, protein translation and several other biological processes (jordão et al. 2011) . specifically, the isoprenic products that are inhibited from being synthesized are dolichol and ubiquinone (goulart et al. 2004 ). the isoprenoid pathway of parasites is distinct from that found in mammals, which makes limonene a reliable constituent of antimalarial drug (goulart et al. 2004 ). thus, the host cell pathway will not be affected by the administration of the drug. pinene, commonly found monoterpene in pine trees is composed of two classesalpha-pinene and beta-pinene. both the classes of pinene were reported to be effective against the w2 strain of plasmodium falciparum, which is resistant to chloroquine (boyom et al. 2010) . of particular interest is the increase in antiplasmodial activity of pinene in cumin seed oil with increase in the distillation time. the study concluded that the optimal distillation time for increased antimalarial activity is 0-5 and 5-7.5 min (zheljazkov et al. 2015) . further investigation is needed to ascertain if distillation time is just increasing the yield of pinenes in the oil or improving the bioactivity of pinenes. the next most abundant terpene, caryophyllene has the ability to both prevent and cure malaria. caryophyllene is an active component of insect repellents especially for mosquitoes and other blood-feeding diptera (maia and sarah 2011) . recent studies ensured that silver nanoparticles synthesized from caryophyllene are highly effective against plasmodium falciparum (kamaraj et al. 2017 ). thus, terpenes could be a safer and a cost effective alternative for malarial treatment. the emerging viral diseases have necessitated the research for new effective antiviral agents such as terpenes. as a result, scientists evaluated various terpenes for their properties, among which monoterpenes showed a good result. monoterpenes are terpene classes that possess two isoprene units. they form a major constituent of essential oils in plants which indicates monoterpenes play a major role in defense for plants (grabmann 2005) . a 2005 study evaluated the in vitro antiviral activity of several essential oils extracted from south american plants (duschatzky et al. 2005) . the oil extracts were tested against three major human viruses-herpes simplex virus-1 (hsv1), dengue virus type 2, and junin virus. the oils that were proved to be virucidal were mainly composed of monoterpenes, namely, carvone, carveol limonene, alphaand beta-pinene, caryophylene, camphor, beta-ocimene, and one sesquiterpene which is germacrene (duschatzky et al. 2005) . a similar study in 2008 analyzed the essential oils of seven plants from lebanon for in vitro antiviral activity (loizzo et al. 2008 ). the viruses under investigation were hsv1 and severe acute respiratory syndrome corona virus (sars cov). the results were positive for antiviral effects, and the major constituents were alpha-and beta-pinene, beta-ocimene, and 1,8-cineole (loizzo et al. 2008) . following this, a 2009 study on salvia cedronella also had similar results which suggested 1,8-cineole, α-pinene, caryophyllene oxide, and sabinene to be the major components of virucidal oils (alim et al. 2009 ). functional data from these studies reveal that a few monoterpenes are shared by various plants for antiviral properties (alim et al. 2009 ). these shared monoterpenes could be of importance as they are present universally. of particular interest is the single main monoterpene that is contributing to the virucidal activity. this was studied by astani et al. (2009) using eucalyptus, tea tree, and thyme essential oil extracts (astani et al. 2009 ). they suggested that monoterpene hydrocarbons have a slightly higher virulent activity compared to the monoterpene alcohols against hsv-1. the monoterpenes with the highest virucidal activity were identified to be alpha-pinene and alpha-terpineol (astani et al. 2009 ). the mechanism behind the virucidal activity was suggested to be direct inactivation of free viral particles. however, the study concluded that more than isolated single monoterpenes, a mixture of monoterpenes are more effective and possessed lesser toxicity to host cells (astani et al. 2009 ). this was further bolstered by another study which evidenced the virucidal property of a combination of monoterpenes obtained from melaleuca alternifolia (zamora et al. 2016 ). the activity was tested against a human flavivirus west nile virus. the results were positive both in vivo and in vitro. the underlying mechanism was predicted to be induced cell cycle arrest at g0 or g1 phase. this indicates that a mixture of monoterpenes could act as a better antiviral agent rather than a single monoterpene (zamora et al. 2016) . recent studies have shown that triketone-terpene adducts also exert antiviral, antimicrobial and antitumor activity (chen et al. 2017 ). these adducts are obtained from myrtaceae as secondary metabolites in the form of sesquiterpenes called myrtucomvalones a, b, and c. the terpene adducts successfully inhibited the respiratory syncytial virus (rsv) (chen et al. 2017) . the bioactive terpenes present in various plants have shown various results for antiviral property. it would therefore be important to look for various plant source rather than various monoterpenes for therapeutic purposes. researchers are also focusing on synthesizing terpene hybrid from fungal sources as they are presumed to have antiviral and uv protective properties (yuan et al. 2017) . terpene synthesis from fungi can lead to cost effective and limited labor methods (yuan et al. 2017 ). the medicinal benefits of terpenes are not limited to pathogenic diseases. terpenes are widely acclaimed for their anticancer activity too. an early 1997 study concluded that a combination of monoterpenes, diterpenes and sesquiterpenes can be effectively used to treat cancers that occur in colon, brain, prostate gland, and bones. 9 it also claimed that administration of terpenes in humans inhibited the growth of prostate cancer cells and sensitized the tumor in such a way it becomes susceptible to radiotherapy (see footnote 9). the major advantage of this treatment was that, the drug can be administered through several routes among which oral and topical were most preferred (see footnote 9). among the different kinds of terpenes, limonene is well recognized as an anticancer agent. limonene is a bioactive food component found in citrus peels, orange peels, and several other citrus fruits (jirtle et al. 1993) . studies have reported limonene to exhibit strong cancer inhibition activity both in vitro and in vivo. the mechanism behind limonene activity is still under investigation. a study by jirtle et al. (1993) reported that limonene acts through induction of transforming growth factor b-1 and mannose-6-phosphate/insulin-like growth factor ii receptors (jirtle et al. 1993 ). in contrast a study by bishayee and rabi 2009) structural studies on limonene reported that they are lipophilic and have the tendency to be deposited in fatty tissues when administered orally. this indicates that limonene can act as an excellent chemopreventive drug for cancer as it can be deposited in the body (miller et al. 2010) . another study in 2013 concluded that limonene acts by suppressing the expression of breast tumor cyclin d1 (miller et al. 2013) . this lead to cell cycle arrest and mitigated proliferation of cancer cells in women with early stages of breast cancer (miller et al. 2013) . recent study showed that limonene from pinecones can kill lung cancer cells in vitro by apoptotic mechanism that is activated through caspase-3 pathway (lee et al. 2017) . these findings indicate a novel application of limonene towards fighting and preventing cancer. not just limonene, but also its metabolite perillyl alcohol is also said to exhibit antitumor activity in pancreatic cell lines through apoptotic mechanisms (sobral et al. 2014; dalessio et al. 2014) . apart from limonene, the terpene thymoquinone has all been widely studied for its chemoprotective and chemotherapeutic activity. thymoquinone is found to be an active constituent of the volatile oils of an annual herbaceous plant called nigella sativa (black cumin) (majdalawieh et al. 2017 ). the pathways affected by thymoquinone to exert its antitumor properties are p53, pparγ, mapk, nf-κb, pi3k/akt, and stat3 signaling pathways (majdalawieh et al. 2017) . thymoquinone has been proved to be anticancerous against several cancers such as breast cancer, skin cancer, non-small cell lung cancer, bile duct cancer, and brain cancer. the basic mechanisms underlying the cancer inhibition is apoptosis and cell cycle arrest (sobral et al. 2014; khader and eckl 2014) . most of the cancer related studies were performed using thermoquinone obtained from the n. sativa extracts. a 2012 study showed that thermoquinone can be obtained in larger amounts from the mint family, namely, monarda didyma and monarda media (taborsky et al. 2012) . thus, thermoquinone from alternative sources has to be tested for its precious potential in cancer therapy. other terpenes that have reported cytotoxic effects on cancer cells include alloocimene, camphor, beta-myrcene, pinene, alpha-and gamma-thujaplicin, terpinene, thymohydroquinone, carvone, camphene, and cymene (sobral et al. 2014) . terpenes being natural compounds are unlikely to affect the healthy cells or create a side effect, which attracts many researchers to exploit its capability in cancer treatment. diabetes is one of the widely prevalent diseases in the world. it is affecting both children and adults in both developing and developed nations (you and henneberg 2016; narayan et al. 2000) . the social and economic burden of diabetes continues to grow and it is expected to rise rapidly in developing countries (sarwar et al. 2010) . in usa, diabetes is one of the leading causes for visual impairment, limb amputation, renal diseases, heart diseases and death (saddinne et al. 1999) . diabetes can be of two types-type 1 (where the immune system of the body acts against the insulin-producing organs) and type 2 (where the insulin produced cannot be used by the body or insulin is produced in low amounts). 10 although there are several medications available, their use is limited due to their adverse effects. some of the commonly found side-effects include low blood sugar, vomiting, nausea, diarrhea, bloating, and weight gain. 11 this led to the research for natural products to be used as effective antidiabetic medication. phytochemicals from the medicinal plants have been recommended for treating type 2 diabetes, of which terpene forms a major constituent (jung et al. 2006) . medicinal plants of oriental morocco were studied for their antidiabetic property in rats. the report showed that terpenes, terpene diols, and terpene diol glucosides form major components of the extracts of plants under study (bnouham et al. 2010) . a similar study on medicinal plant and their natural products that were reported from 2001-2005 was conducted by jung et al. 2006 . this study was focused on non-insulin-dependent diabetes mellitus (type 2), and it proved that terpenes along with few other secondary metabolites such as alkaloids and flavonoids exhibit antidiabetic potential (jung et al. 2006) . the most promising terpene compound for treating diabetes is called andrographolide which is a diterpenoid lactone (brahmachari 2017) . this compound forms the major component of the leaves of the small herbaceous plant andrographis paniculata. a. paniculata is an asian plant that has already been reported to be used in traditional medicines for its therapeutic nature (brahmachari 2017) . the terpenoid acts by reducing the plasma glucose and increasing the utilization of glucose by the body in diabetes mellitus rats (gupta et al. 2008 ). the actual mechanism by how it does this is it activates the alpha-adrenoreceptors to increase the release of an opioid peptide beta-endomorphin (brahmachari 2017) which is reported to be secreted in low amounts in diabetic rats (forman et al. 1985) . this increased secretion in turn activates the opioid μ-receptors. these receptors can effectively curb the hepatic gluconeogenesis (glucose synthesis from non-carbohydrate precursors) and elevate the utilization of glucose by muscles. finally, this results in a reduced plasma glucose concentration (brahmachari 2017) . andrographolide is also observed to prevent the secondary complications of diabetes such as diabetic retinopathy, a condition that will lead to blindness (brahmachari 2017) . it significantly weakens the retinal angiogenesis and inflammation during the development of the disease (brahmachari 2017) . moreover, it can also fix the impaired or extended estrous cycle in diabetic rats (reyes et al. 2006) . andrographolide was orally administered in all the above studies. this indicates its efficiency for being used as a lead molecule in the future drugs designed for treating diabetes mellitus. another widely known terpene is curcumin obtained from curcuma longa which commonly called turmeric (nabavi et al. 2015) . it exhibits high antidiabetic property and acts by quashing the oxidative stress and inflammation. by regulating the polyol pathway, it can also reduce the plasma glucose and levels of glycosylated hemoglobin (nabavi et al. 2015) . moreover, curcumin is also reported to activate the enzymes present in the liver that are essential for glycolysis, gluconeogenesis, and lipid metabolism (zhang et al. 2013) . alike andrographolide, curcumin is also reported to reduce the complications of diabetes (nabavi et al. 2015) , for example, liver disorder which is a common manifestation of diabetes type 2 (zhang et al. 2013) . curcumin treats these disorders by reducing the liver weight and lipid peroxidation products. further, it is also reported to normalize the levels of fetuin-a in serum that contributes to insulin resistance and fatty liver in diabetic rats (zhang et al. 2013) . other complications that can be attenuated by curcumin include diabetes associated-retinopathy, microangiopathy, neuropathy, and nephropathy (zhang et al. 2013) . these findings confirm that curcumin is likely to be used in the future for diabetes treatment. depression has become a serious health concern by contributing to the emerging mental and emotional disorders throughout the world. it is hitting both the developed and developing countries. depression can pave way to various health issues from alcoholism to heart diseases (holden 2000) . it is also said to increase the rate of mortality significantly in breast cancer patients (hjerl et al. 2003) . moreover, depression immobilizes its victims thereby leading to economic loss (holden 2000) . by analyzing the social and economic burdens caused by depression, researchers have stepped out towards finding novel stress-relieving drugs. synthetic drugs have serious side-effects and unintended interactions with the body that negatively affects the treatment outcome (jawaid et al. 2011) . hence this necessitated the need for natural drugs. terpenes serves as one of the most relevant bioactive compound for treating depression and therefore can open doors for designing natural or synthetic antidepressant drugs (bahramsoltani et al. 2015) . twenty-five percentage of antidepressant drugs prescribed by doctors are obtained from herbs through various extracts (saki et al. 2014) . to estimate the important compounds contributing to the antidepressant effect, saki et al. (2014) performed an electronic database based study. the results revealed that terpenes formed a major part of the extracts of medicinal plants that exerted antidepressant effects (saki et al. 2014) . thus, scientists focused on identifying the active principles of plant extracts contributing to the antistress effects. different plant had different acting compounds. among the several terpenes, linalool and beta-pinene are commonly found to be active principles (both guzmángutiérrez et al. 2015; guzmán-gutiérrez et al. 2012) . they were discovered from the extracts of medicinal plants litsea glaucescens and tagetes lucida and flowers of lavender (appleton 2012; guzmán-gutiérrez et al. 2012; guadarrama-cruz et al. 2008 ). these monoterpenes act by interacting with the 5ht1a receptors of the serotonergic pathway. serotonins are important in the fact that their release and re-uptake levels can be altered to overcome stress (chaouloff 2000; guzmán-gutiérrez et al. 2012) . they also interact with adrenergic receptors of the body that play a major role in stress-induced behavioral changes (pandey et al. 1995; guzmán-gutiérrez et al. 2015) . another interesting finding is the interaction of beta-pinene with dopaminergic receptors namely d1 receptors. this is the mechanism followed by most of the antidepressant drugs available in the market (guzmángutiérrez et al. 2015) . a more interesting study would be to examine the beta-pinene and linalool efficiency through inhalation tests. this is because these monoterpenes are aromatic compounds that generally have an enhanced activity when inhaled as they can directly hit the central nervous system (guzmán gutiérrez et al. 2014) . apart from monoterpenes, sesquiterpenes also exhibit antidepressant effects. one striking example is beta-caryophyllene which was proved to ameliorate the depressive symptoms in mice (bahi et al. 2014) . the underlying mechanism of this compound is binding to a receptor called cb2 and activating it. cb2 is found in the brain and immune cells and plays a major role in regulating depressive-related disorders (bahi et al. 2014) . thus beta-caryophyllene curbs depression by acting as a cb2 receptor agonist (bahi et al. 2014) . other terpenes that have effective antidepressant properties include hyperforin which is present in the extracts of hypericum perforatum (subhan et al. 2010) . it has been shown that the extracts of h. perforatum differ in their antidepressant potential with the difference in concentration of hyperforin present in the extract (laakmann et al. 1999 ). similar to many other antidepressants hyperforin acts by inhibiting the neuronal uptake of mood regulators such as serotonin, dopamine and norepinephrine. in addition, it also has its own unique mechanism of controlling depression by inhibiting the neurotransmitters gaba and l-glutamate uptake (müller et al. 2001) . another fascinating antidepressant plant is valeriana wallichii, which is a short perennial herb. this plant not only reduces the stress and anxiety levels but also improves the symptoms of depression in humans (bhattacharyya et al. 2007 ). the major components of valeriana extracts are terpenoids called maaliol, patchouli alcohol, and 8-acetoxypatchouli alcohol (subhan et al. 2010) . the terpenoid-less extract of valeriana was found to be devoid of antidepressant activity which indicates that terpenes are the active components involved in reducing the depression (subhan et al. 2010 ). folk medicine has always been an eye-opener for designing novel drugs for diseases. to be more specific, almost three-fourths of the plant-based drugs were created based on the knowledge of folk medicine (table 15 .4) (efferth et al. 2008) . realizing this fact, western worlds are now turning back into old medicines and bioactive plant components to treat modern diseases (efferth et al. 2007 (efferth et al. , 2008 . this has boosted the export rates of chinese medicinal products (based on traditional chinese medicine) from china to other developed nations. plants used in traditional chinese medicine (tcm) are being extensively studied for their secondary metabolites and their therapeutic properties (efferth et al. 2007 ). one of the active principles of tcm products is terpenes (liu and jiang 2012) . due to their large availability and diversity, terpenes contribute the most to industrial and medicinal applications among all the secondary metabolites of plants (zwenger and basu 2008) . paclitaxel is one of the most successful terpenes available in the market today (efferth et al. 2008) . it is made out of yew trees which is a medicinal tree used in tcm. 12 raw material from yew contains taxol (brand name of paclitaxel) which is used in the treatment of cancers in breast, lung, ovary, pancreas, cervix, and blood (see footnote 12). 13,14 two variations of this drug are used now in chemotherapyconventional paclitaxel and albumin-bound paclitaxel (see footnote 13). the advantage of the latter is that concentration increases in tumor cells at a rate higher than that of the former (see footnote 13). the mechanism of anticancer activity is described as disruption of microtubules in the mitotic spindle, which will lead to incomplete chromosome separation thereby causing cell death (see footnote 13). in tcm and ayurveda (herbal medicinal science mainly developed in india), healers used the twigs and barks of the tree to make a special kind of tea that can be given to patients suffering from cancer. however due to the slow growing nature of yew tree, paclitaxel nowadays is produced by coalescing the products of endophytic fungus that grows under the tree and the bark of the tree 15,16 (heinig et al. 2013 one more common terpene present in the drugs used in tcm is pinene (wu et al. 2008) . pinene exhibits therapeutic properties such as anti-inflammatory, antiseptic, anticancer, and antibiotic properties. 17, 18 the source for pinene is eucalyptus and other related coniferous trees (see footnote 17, sartorelli et al. 2007) in olden days, the juice from the bark of eucalyptus was collected and mixed in water, milk or wine to be used as a drug (see footnote 17). currently, they are extracted in the form of oil and sold in the form of syrups and lozenges. 19 as eucalyptus oil contains several monoterpenes, a study analyzed the different constituents of eucalyptus oil for its effectiveness against bacteria. here it was concluded that alpha-pinene is the best monoterpene with the highest inhibitory activity (sartorelli et al. 2007) . recently scientists are studying another primary terpene in eucalyptus called cineole. cineole is reported to improve the memory power, cognitive performance and attenuate the symptoms of alzheimer's disease in humans (see footnote 19; moss and oliver 2012) . in addition, studies also showed that cineole is capable of improving the health of bronchitis patients by reducing their cough (fischer and dethlefsen 2013) . this is in agreement with the fact that eucalyptus oil was used as an expectorant in ayurvedic medicine. 20 it is also known that local brazilians used the eucalyptus leaves to treat several human diseases such as cancer (mathias et al. 2012) . further reports also suggest that eucalyptus oil has been involved in ancient indian ayurvedic and greco-european medicine systems (see footnote 19). ayurveda is a popular medicine system which originated about 3000 years ago in india. the ayurvedic medicines are based on medicinal herbs, minerals, and metals (see footnote 16) along with diet regimes such as vegetarianism (caldecott 2006) . this system of medicine has proven to cure chronic disorders that could not be treated by western medicine (sharma et al. 2007) . interestingly a lot of medicinal plants used by ayurvedic practitioners owe their therapeutic property to their terpene contents. one good example is turmeric, a family of ginger which is regarded as "golden goddess" by medical practitioners (see footnote 18). 21 it has numerous therapeutic properties that includes anti-inflammatory, antioxidant, anticancer, antiseptic, antiplasmodial, astringent, digestive, diuretic, and many more (see footnote 18). 22 recently, scientists discovered that most of the turmeric's properties are laid out by the yellow-colored terpene-curcumin (kocaadam and şanlier 2017) . studies are now trying to create curcumin analogues to improve the effects and activity of natural curcumin (kocaadam and şanlier 2017) . another popular example is clove which was used by both ayurveda and tcm as a painkiller in dental cases. it was applied topically on cavities to relieve toothache and abdomen to treat digestive problems (alqareer et al. 2006) . the essential oil of clove is mostly composed of eugenol, a bioactive terpene that is responsible for clove's aroma (alqareer et al. 2006) . eugenol by itself is said to enhance the blood circulation in the body and improve metabolism (see footnote 22). thus, based on the above data we can conclude that various terpenes have been in use even before their discoveries by modern science, due to their amazing medicinal properties. a schematic summary of different terpenes and their medicinal uses, that we discussed, is provided below in fig. 15 .1. 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valeriana wallichii extracts and antidepressant-like response profiles identification of potential sources of thymoquinone and related compounds in asteraceae, cupressaceae, lamiaceae, and ranunculaceae families euphorbia diterpenes: isolation, structure, biological activity, and synthesis volatility-dependent 2d ir correlation analysis of traditional chinese medicine 'red flower oil' preparation from different manufacturers enhancing production of bio-isoprene using hybrid mva pathway and isoprene synthase in e. coli type 1 diabetes prevalence increasing globally and regionally: the role of natural selection and life expectancy at birth polyketide-terpene hybrid metabolites from an endolichenic fungus pestalotiopsis sp the in vitro and in vivo antiviral properties of combined monoterpene alcohols against west nile virus infection the scientific contributions of m. judah folkman to cancer research novel norsesquiterpenoids from the roots of phyllanthus emblica tanshinones: sources, pharmacokinetics and anti-cancer activities curcumin and diabetes: a systematic review distillation time as tool for improved antimalarial activity and differential oil composition of cumin seed oil plant terpenoids: applications and potentials holy basil/ tulsi eugenol, β-elemene, β-caryophyllene and germacrenerestores functions of nervous system increases fertiltity used to treat asthma and cold key: cord-034066-fsp7e5x5 authors: di figlia-peck, stephanie; feinstein, ronald; fisher, martin title: treatment of children and adolescents who are overweight or obese date: 2020-10-21 journal: curr probl pediatr adolesc health care doi: 10.1016/j.cppeds.2020.100871 sha: doc_id: 34066 cord_uid: fsp7e5x5 nan m anaging the millions of children and adolescents who are either overweight or obese has become a major challenge for the healthcare community. in 1997, an expert committee was convened by the maternal and child health bureau of the health resources and services administration (hrsa), department of health and human services, (dhhs) to develop guidelines for healthcare providers. 1 in 2005, the american medical association, in cooperation with hrsa and the center for disease control and prevention, created an expert committee to update those initial guidelines. 2 and in 2008, the agency for healthcare research and quality of the hhs came out with an evidence-based/technology assessment entitled "the effectiveness of weight management programs in children and adolescents." 3 in addition to these government-sponsored guidelines, recommendations for management of overweight and obesity in this population have been issued by multiple other organizations. the one directive they all have in common is that a multicomponent program that focuses on physical activity, diet, and behavioral change should be the first line of treatment offered. this article highlights the evidence-based data, presents the various ways in which this multicomponent approach can be implemented, and includes the roles of school programs and bariatric surgery as weight management options. family-based group sessions coordinated by a registered dietitian (rd/rdn) are a crucial part of multicomponent interventions. the academy of nutrition and dietetics, which issued its pediatric weight management evidence-based guidelines in 2015, has reported positive weight status outcomes, both shorter-term (6 months) and longer-term (12 months), when group pediatric weight management sessions and family participation are coordinated. 4, 5 individual family and mixed-format (which includes some time with individual families and some group time) approaches have been found to be superior to group-only approaches as per the latest us preventative services task force (uspstf) recommendations. 6 however, including in addition to these governmentsponsored guidelines, recommendations for management of overweight and obesity in this population have been issued by multiple other organizations. the one directive they all have in common is that a multicomponent program that focuses on physical activity, diet, and behavioral change should be the first line of treatment offered. the academy of nutrition and dietetics, which issued its pediatric weight management evidence-based guidelines in 2015, has reported positive weight status outcomes, both shorter-term (6 months) and longer-term (12 months), when group pediatric weight management sessions and family participation are coordinated. 4, 5 some group sessions may offer the opportunity for social support and improve cost effectiveness. 7 the dose of treatment has a strong impact on success. multicomponent behavioral interventions of moderate (26à75 h of treatment contact per year) to high intensity (> 75 h) for obese children and adolescents, ages six and older, have been shown to yield short term improvements in up to 12 months. obtaining a qualitative assessment of a patient's diet with a particular focus on dietary patterns thought to be linked to excess energy intake and adiposity is recommended, as intervening with these patterns can significantly reduce intake and potentially improve nutritional status. 8 tailoring interventions by considering patient and family motivation, as well as readiness for change, is optimal. the family-based approach can be modified based on the age of the patient and the degree of parental involvement. it should be noted that family involvement has been shown to be less effective when the patients are older teens. 9 behavioral treatments at the heart of behavioral treatment for obesity is determining what behaviors are modifiable and what therapies to use to help patients achieve the needed modifications. motivational interviewing (mi), which is a patient-centered counseling style, has been shown to be effective in primary care settings. 10 a dietitian should be included, as the rdn's knowledge and skill base are critical in the ongoing process of addressing the diverse needs of clients and families. 4, 10 cognitive behavioral management and gradual stepwise change have been explored in depth for childhood and adolescent obesity treatment. individuals get acclimated to recommended changes over time by making adjustments in their dietary patterns and food environment and by learning to set limits on eating unhealthy food. short-term goals are established in order to lead to long-term habits that change the way individuals and their families think about food. cognitive behavioral therapy (cbt) focuses on breaking the negative cycle that is a part of weight-related difficulties in obesity, the "maladaptive daily patterns, cognition that is distorted, and problematic behaviors" cited by wilfley et al. 11 it allows for a restructuring of daily patterns. bloom et al. explores utilizing a form of cbt known as cbt-af to address appetite awareness and cues for eating. 12 caat is an adapted version used with children and adolescents to sensitize them to recognize and respond to internal appetite cues such as hunger and satiety in order to improve their self-regulation of energy intake. results of one study showed a significant reduction in body mass index (bmi) for children in a caat group compared to those in a control group. however, this impact was only studied short term. the researchers concluded that caat holds promise as a treatment modality since overweight and obese children are often less effective in regulating food intake compared to normal weight children. 13, 14 in the transtheoretical model of change, in which change occurs in stages, the readiness of parents for personal change, as well as their readiness to help their children make changes, becomes a pivotal factor for success in a weight management program. 15 tailored messages to parents may help modulate their "decisional balance," (the value of making behavioral changes versus the value of not making any changes) and contribute to the likelihood of treatment success for their children. yet influencing parents so as to influence their children in terms of weight management behaviors can be a challenge. weight loss is a complex behavior which encompasses two separate "domains" of changeà eating habits and physical activity. although these are often considered together, each carries unique challenges with respect to perceived confidence and readiness for change. 16, 17 in a cross-sectional study with a convenience sample of parents (or guardians) of children attending a tertiary care pediatric obesity clinic, parents completed surveys initially and again on follow up visits to assess their readiness for change. 16 those in the action/ cognitive behavioral management and gradual stepwise change have been explored in depth for childhood and adolescent obesity treatment. individuals get acclimated to recommended changes over time by making adjustments in their dietary patterns and food environment and by learning to set limits on eating unhealthy food. maintenance state of change were more likely to be actively making changes to multiple eating behav-iorsài.e. availability of sugar-sweetened beverages (ssbs) and salty snacks, and in physical activity patternsài.e. reaching recommended levels of increased activity and limiting screen time. their children were more likely to be more physically active and to consume less fast food and more fruits and vegetables than the children of parents in the other stages of change. 16 parents who believed their own weight was a health problem were less ready to make changes to their children's diet. 18 these authors suggest that maintaining both parent and patient motivation should be a focal point of treatment and that this may entail a variety of approaches, such as using texting or other electronic devices to assess the stage of change for readiness and decisional support. 18 use of mobile health technology as an adjunct to behavioral based weight management strategies is becoming more common. chen and researchers reported on a convenience sample of self-identified chinese-american adolescents with bmi 85th percentile who participated in a culturally focused intervention called smart start. 19 it provided general health education, wearable fitness trackers, online educational modules, and tailored biweekly text messages. a benefit in outcome occurred in both the control and intervention groups. however, over a six month period, the intervention group, as compared to the control group, had "statistically greater changes" in bmi that were associated with less fast food intake, a lower intake of ssbs, and an increase in physical activity levels and decreased sedentary behavior. 19 overall, mobile health use has shown mixed benefits for weight management in adolescents and young adults. 20 other mobile health initiatives have resulted in weight loss in the experimental groups that was not sustained 21, 22 or have displayed no further benefits above that of the standard care group. 23 researchers have thus noted limited evidence of efficacy of mobile health interventions as a stand-alone treatment modality. 24 the impact of combining the mobile health approach with components of behavior based interventions has been examined by cueto et al. 25 they evaluated the original kurbo app (circa 2014) before it became kurbo ww. 26 designed to promote behavior change and encourage healthy lifestyle choices, it used the evidence-based traffic light diet approach 27 and kurbo health coaching through the incorporation of behavior substitutions and habit formation. 28 although kurbo includes components of behaviorbased interventions proven successful in pediatric and adolescent weight management, it has come under fire for promoting behaviors that can be perceived as overly restrictive and potentially promoting eating disorder behaviors. 29 questions have been raised based on degree of weight loss in young subscribers and whether adequate monitors are in place to determine that degree. prior studies have warned about the potential for "growth velocity to be negatively impacted when caloric intake is restricted," and thus growth velocity must be followed carefully during and after weight loss in older children and younger adolescents, and medical supervision may be warranted. 30, 31 other combined interventions utilizing mobile health apps have yielded partial success. one 12month technology-based program for adolescents with type 2 diabetes "was not sufficient to produce weight loss with the combination of web intervention and group sessions and telephone follow up, but improvements in sedentary behavior and use of behavior change strategies expected to lead to behavior change was evidenced." 32 telemedicine, in theory, should be able to compensate for some of the barriers that prevent access to and utilization of family based comprehensive behavioral interventions for child and adolescent obesity. 33 these barriers include time, transportation, access, cost, scheduling challenges, stigmatization, language barriers and more. [34] [35] [36] [37] rural populations have been studied for feasibility and satisfaction with telemedicine treatment approaches, and results have been comparable to standard treatment outcomes. 38 urban populations can face similar barriers to attendance of programs held in hospitals or university medical use of mobile health technology as an adjunct to behavioral based weight management strategies is becoming more common. settingsà delays in acquiring care, fear of being judged based on native language or residency, and possible stigmatization. 39 consequently, there have been studies here too (even prior to the covid-19 pandemic) regarding the incorporation of telemedicine as a supplemental arm of treatment modalities involving group sessions and mixed formats with medical staff including physicians, nurse practitioners (nps), nurses, psychologists, family counselors, dietitians, physical therapists, exercise specialists, and social workers. 38, 39 with the dramatic increase in the use of telemedicine brought about by the covid 19 pandemic, this modality of treatment will certainly be utilized and studied considerably more in the upcoming months and years. mobile apps have proved an engaging way to involve children in health behavior changes, 40 allowing for delivery of health information in a portable, "entertaining" way. [41] [42] [43] these apps are capable of promoting some of the expert recommendations for healthy eating and physical activity, including setting goals/limits and reducing intake of ssbs, but they often do not go deeper into behavior change. one app, hyperant tm , utilized a set of "hyper activity cards tm " to give children ideas for health-promoting behaviors including physical activity, healthy eating, and sleep. 44 however, it only provides user messages without offering the opportunity for interaction. in a meta-analysis of mobile health technologies for selfmonitoring, darling et al. concluded that self-monitoring techniques using mobile health technologies have a small but significant effect on weight status in children and adolescents. 45 population health initiatives a more "macro approach" for educating and guiding children, adolescents, their families and guardians is called for to achieve greater success in maintaining better health and weight management. several such programs are described below. the choosemyplate teaching initiative from the u.s. department of agriculture (usda) came out of the need for a vehicle to effectively and "with maximum visibility" communicate the 2010 dietary guidelines for americans (dgas) in order to foster a healthier lifestyle. 46 using print and online resources to engage the public, it was translated into several languages, incorporated into health curriculum resources created for nutrition education for children and adults, and promoted to nutrition communicators, educators and the food industry, calling upon them to "get the message out." [47] [48] [49] its message: "americans can achieve a healthier weight by eating more of some foods," was thought to be one that consumers could embrace. when one's plate has a larger proportion of lower calorie vegetables, they, in essence sense, "crowd out' the more calorically dense other foods on the plate like refined grains and high fat proteins. thus, adding foods, rather than taking away foods, can result in a calorie deficit. designed to "impact behavior during meal planning" and "perception during meal consumption," this initiative aimed to be seen by individuals and groups as a positive way of collectively altering energy balance. choosemyplate calls for a shift in consumption patterns. it emphasizes less processed foods and more of whole grains, lower fat and non-fat dairy items over full-fat varieties, water in place of ssbs, and protein alternatives, including leaner meats. along with less saturated fat and added sugars, lower sodium options are promoted. central to this multimodal plan is the plate icon ( fig. 1 ) that replaces the food guide pyramid as both visual cue and accepted standard. 48, 49 the most current recommendations, as per myplate, my wins (see below), directs people to "find your healthy eating style and maintain it for a lifetime" by making half of the meal plate fruits and vegetables (varying the veggies and focusing on whole fruits), making a quarter of the plate grains (half of them whole grains), and making the remaining quarter of the plate proteins (varying the protein routine). individuals are advised to move to low-fat or fat-free milk or choosemyplate calls for a shift in consumption patterns. it emphasizes less processed foods and more of whole grains, lower fat and non-fat dairy items over full-fat varieties, water in place of ssbs, and protein alternatives, including leaner meats. along with less saturated fat and added sugars, lower sodium options are promoted. yogurt for dairy intake, which is depicted alongside on the right of the icon's plate. the "right mix" is based on variety, amount, and nutrition content. the original myplate teaching campaign was revamped to reflect changes in the updated dgas (2015à2020). myplate, my wins, launched in 2015, strongly focuses on food patterns. it added the concept of "a healthy eating style" which can be achieved with "small changes" to promote the goal of getting individuals to realize that "what you eat and drink over time matters and can help you be healthier now, and in the future," messaging that reflected the evolving emphasis of the dgas. the public was encouraged to be more engaged and active in their health, and was invited to virtually share personal experiences with my plate, my wins on social media using #myplatemywins. the present day choosemy-plate.gov website includes printable materials, images, and graphics available as downloadable pdfs, jpgs, and other files-all in the public domain so that no permission is required to print, reproduce, or use them. resources have grown to include a host of topics, from meal planning and food safety to physical activity and seasonal resources. information continues to be available in diverse formats like toolkits, quizzes, infographics, and videos. researchers out of the behavioral health and nutrition department at the university of delaware used myplate to test whether peer education improved selfefficacy, perceptions and attitudes toward healthy eating, and physical activity. 50, 51 they concluded that peer education could promote improved knowledge and attitudes about myplate among college students and increase their self-efficacy, helping them make healthier decisions with regard to food and food intake. the pilot first year experience course curriculum developed at the university became mandatory coursework for all incoming freshmen. 41 a florida study of elementary school children whose families qualified for federal assistance via the supplemental nutrition assistance program (snap), utilized the six-lesson youth understanding myplate (yum) curriculum to teach the students through grade specific activities. the children reported an increase in intake of fruits and vegetables, grains, low-fat/fat-free dairy, healthy snacks, eating breakfast, and physical activity, compared to baseline. 52 5-2-1-0 let's go! is another nationally recognized program that aims to create environments supporting healthy choices, healthy habits, and healthy living within a multi-setting model. [53] [54] [55] [56] developed in maine in 2006 by a group of professionals on a mission to tackle childhood obesity by using evidence-based tools and strategies, it has expanded and gained momentum through its strong, far-reaching program and campaign designed to reach out to families where they live, learn, work, and play. its premise is that if children and families are exposed to the same health message in multiple places across their community, and if those places have policies and environments that support healthy choices, then children and families will be more likely to adopt those behaviors and maintain them in their daily lives. the foundation for change as modeled in the 5-2-1-0 healthy habits message is based on the following daily measures: 5 or more fruits and vegetables, 2 h or less of recreational screen time (tv/ computers to be kept out of the bedroom and no screen time under the age of 2), 1 h or more of physical activity, and 0 the foundation for change as modeled in the 5-2-1-0 healthy habits message is based on the following daily measures: 5 or more fruits and vegetables, 2 h or less of recreational screen time (tv/computers to be kept out of the bedroom and no screen time under the age of 2), 1 h or more of physical activity, and 0 sugary drinks and more water intake (fig. 2) . sugary drinks and more water intake (fig. 2) . though this message has been found to increase awareness and healthy behaviors, it remains to be seen if that will translate to concrete behavioral changes. many pediatric and primary care offices across the country have started to implement 5-2-1-0 let's go! into their practices to potentially impact the health of their patients, as have hospital-based specialty programs. the power kids weight management program of cohen children's medical center at northwell health is the authors' multidisciplinary program for overweight and obese children and adolescents, 8 to 18 years of age. in advance of meeting with program staff or at the initial assessment by the program's registered dietitian nutritionist (rdn), prior to any interventions, the patient or the parent/guardian is asked to fill out a healthy habits questionnaire adapted from and directly correlated to the 5-2-1-0 let's go! program (fig. 3) . one version is for children up to 9 years of age, another for 10 to 18-year-olds, and both are available in spanish as well as english. the power kids questionnaire uses a modified food-frequency survey style to ask questions regarding food and beverages and includes other questions that address time allocation for activity and sedentary pursuits as well as family meal patterns and access to tv. what emerges are overall patterns, habits, and choices, ending with a glimpse as to what the child or adolescent is willing to change. answers to the questions help guide the direction of behavioral, nutritional, and exercise interventions. focusing on domains where program participants exhibit deficiencies, while reinforcing already established positive health-related behaviors, helps to pave the path to successful weight management. the goal is to use the 5-2-1-0 message to encourage the children and adolescents in the program to develop healthy habits that can positively impact what would otherwise be their trajectory for further excess weight gain and the associated comorbidities of obesity. let's move is the comprehensive initiative launched in 2010 by former first lady michelle obama the same day that president barak obama signed the memorandum creating the task force on childhood obesity. in partnership with the alliance for a healthier generation, it is dedicated to solving the problem of obesity "within a generation" so that "children born today will grow up healthier and be able to pursue their dreams." 57 the focus is on creating a healthy start for children, empowering parents and caregivers, providing healthy food in schools, improving access to healthy affordable foods, and increasing physical activity. one of its many ambitious goals is the commitment to giving children a voice and a presence. families are encouraged to recognize that children can create healthy lunches from their own kitchens and express their unique preferences as to what "healthy eating" translates into for them. the healthy lunchtime challenge has drawn representatives from every state and territory in the united states, and the accumulation let's move is the comprehensive initiative launched in 2010 by former first lady michelle obama the same day that president barak obama signed the memorandum creating the task force on childhood obesity. of recipes from the annual challenges is accessible online as "historical material." 57 the let's move! outside program, developed to bridge the growing disconnect between young people and the great outdoors, and to emphasize the need for active play, has been adopted by the ymca of the usa, through its youth development division, using programs and services shown to be instrumental in their diabetes prevention program (dpp) trials. 58 eligible children and adolescents, ages 5à17, representing a wide variety of socioeconomic backgrounds, were recruited for a randomized computer-assisted intervention that included their families, to assess whether eliminating financial barriers to ymca membership could encourage increased physical activity in the environment of a supportive family. 59 extensive resources were available to those who utilized the services. all participants and their parents and guardians were scheduled to attend 4 nutrition classes administered by a registered dietitian (rd) and to return for evaluation at 2, 4, 6, 9, and 12 months. children were randomized to nutrition class only (n = 39) or nutrition class and free family ymca membership (n = 44). nutrition classes did not differentiate between those in the control and treatment groups. of the 36 evaluable participants randomized to treatment, only 27 ever visited the ymca, with a median of 5 visits reported. overall attendance at scheduled study-related visits was poor. only 2 participants in each group attended all 6 scheduled visits. for nutrition classes, at least 1 class was attended by 67% of the treatment group, but only 30% of controls. attendance in the nutrition classes led to improvements in nutritional intake for both groups. four participants in the control group and 1 in the treatment group achieved the target reduction of 2 bmi percentile points. there was a positive, but very small, relationship for ymca attendees between the number of visits and the loss of either bmi or weight, which was not statistically significant. curr probl pediatr adolesc health care, & &&&& another major initiative promoting physical activity and healthy eating among children-(in this case, as young as kindergarten and through 12th grade) that has been studied and evaluated is the nfl play 60 fit-nessgram partnership project, led by teachers in school settings across 32 national football league franchise markets. (its two most popular programs are fuel up to play 60, in collaboration with the united states dairy association (usda), and the nfl play 60 challenge created in conjunction with american heart association (aha). the latter has its own app which originally allowed users to choose an avatar with which to complete a course through a virtual outdoor park while listening to health promoting messages like "make sure you drink enough water today"it no longer includes an "in the game" motion sensor but still gauges and delivers health concepts.) the longitudinal impact of nfl play 60 programming was measured using data based on students from 497 schools who completed fitnessgram assessments annually, starting in 2011 through 2015. for schools that participated in the program, annual improvements in aerobic capacity were significantly greater for both girls and boys, compared with non-programming schools. both girls and boys in participating schools showed annual improvement in bmi healthy fitness zone achievement. students in schools that implemented the program for the entire 4 years tended to have better improvements in aerobic capacity than those in schools enrolled for only 2 or 3 years. 60 it is fair to say that each of the national initiatives described in this section had some impact on nutrition and physical activity for many children and adolescents but that the impact was modest for most and minimal for many. going forward, it can prove useful to combine the messages of these multiple programs into one unified message that can be promoted throughout the country in a way that will strengthen their message and thereby yield a stronger effect on the nutritional and physical activity patterns for the youth of the nation. advances in technology have brought about the proliferation of electronic devices now available to children and adolescents who are spending long durations of time in sedentary activities involving handheld devices and video consuls. current guidelines call for limiting sedentary screen time to 2 h or less. 61 among the many concerns being addressed is that increased time on electronics/screen time becomes a potential source of additional energy intake. in a clever harnessing of this dynamic, health professionals are exploring the use of electronics and gaming for getting children to be more physically active. games like wii/wiiu, xbox connect, nintendo, and variations of them have offered small promise. active video games can acutely increase light to moderate physical activity. however, they are unlikely to impact increased habitual activity or significantly decrease sedentary behaviors. 62 rose et al. in their systematic review of digital interventions for improving diet and physical activity behaviors in adolescents, struggled with the heterogenicity of studies not being conducive to a meta-analysis and urged setting up future research initiatives in digital health as a cost-effective medium for health promotion. 63 a great deal of thought and programing is being directed to creating challenges and monitoring progress with physical activity. and sometimes the unexpected turns up with great outcomes. for a time in 2016, the pok emon go app set off a frenzy of interest in walking, sometimes long distances, to find and catch pok emon avatars. 64 an estimated 9à21 million people used the app and increased their daily step count, with some reaching as many as 15,000 steps a day. 65 step challenges have worked well in the adult population with competitions awarding badges, status recognition, and prizes for accumulating steps. in the early 2000s portable watches that were affordable and fashionable were introduced for use in tracking steps. prior to this, they had only been available at research grade. studies exploring step tracking have shown promising results in that a positive feedback loop is established, whereby accumulating steps reinforces continuation of the activity. efforts at encouraging step initiatives in children and adolescents hone in on impacting their motivation, which is often lacking. 66 research on how to encourage more physical activity among studies exploring step tracking have shown promising results in that a positive feedback loop is established, whereby accumulating steps reinforces continuation of the activity. children and adolescents yields findings on how to most effectively use pedometers in combination with other treatment modalities. organizations including the american medical association (ama) and the united states preventive services task force (uspstf), along with healthcare organizations and professionals abroad, have recommended counseling to promote increased physical activity. 67 pedometers, which are inexpensive and wearable devices, can provide children with objective ways to self-monitor their physical activity. several studies of weight management interventions have shown that children can successfully increase their step count from baseline as part of an intervention. 68 yet these studies fail to consistently demonstrate a significant change in bmi percentile from controlled conditions. 68,69 staiano et al. were able to demonstate weight loss in groups of children issued pedometers as part of a 10week, family-based weight management intervention which included physical activity, nutrition, and behavior modification (as well as money compensation). 68 those in the group issued pedometers and a step count goal increased their daily step count, as well as reduced their bmi and bmi z score significantly more than those issued a pedometer without a step goal count. both groups saw a reduction in bmi and an increase in step count from baseline. these same children issued pedometers (with or without a step count goal) had increased subjective health and increased health-related quality of life. ostendorf et al. examined what leads some people to be consistent exercisers and demonstrated that weight loss maintainers weren't using continuous calorie restriction to maintain their weight. 70 instead, the weight loss maintainers had a much higher energy burn from exercise despite eating approximately the same number of calories per day as the control participants with overweight/obesity. it takes a significant time commitment to achieve the level of activity observed in these weight-loss maintainers. in a commentary on the role of exercise, martin and church challenge researchers to identify the physiological, psychological, and environmental factors that help people maintain weight loss through large amounts of exercise so that strategies can be implemented for future weight loss maintenance success. the benefits of exercise cannot be argued. regular exercise can lower stress, moderate anxiety, and improve overall quality of life; however, there is great variation in these outcomes. 71 targeting the agent of change knowing that parents can be effective in modulating childhood obesity by serving as role models for children's eating and physical activity behavior, and knowing the positive impact parental involvement in childhood obesity efforts carries, golan and crowl compared targeting parents exclusively for treatment with a child-only intervention. 72 group sessions were utilized in this family-based health center intervention treatment, with parents attending 14 onehour support and educational sessions that started as weekly, became biweekly, and then took place once every six weeks with clinical dietitians delivering the topics. two similar groups were established, with 15 families participating in each, discussing such topics as limited responsibilities, nutrition education, eating and activity behavior modification, decreasing stimulus exposure, parental modeling, problem-solving, cognitive restructuring, and coping with resistance. parents were encouraged to practice an authoritative parenting style as opposed to an authoritarian style. 71 in authoritative parenting, "parents are both firm and supportive and then assume a leadership role in the environmental change with appropriate granting of child autonomy," whereas in the authoritarian style, child feeding practices are controlled by the adults 73à77 children in the child-only group were prescribed a 1500 calorie per day diet and participated in 30 one-hour group sessions led by a clinical dietitian. two similar groups were held with 15 children allocated to each. the first 7 sessions were conducted weekly and the remainder were held biweekly for the period of one year. at the end of the intervention, 35% of children in the parents-only group reached a non-obese status, compared to 14% in the child-only group. at the one-year follow-up, or one year after program termination, the weight loss in the children of the parent-only group was statistically significant compared with that of the child-only group. at the two-year follow-up, there was a mean reduction in overweight of 15% in children of the parent-only group and an increase of 2.9% in children of the child-only group. at the seven-year follow-up, both treatment conditions demonstrated substantial weight loss. however, the mean reduction of overweight status was 29% in children of the parent-only group and 20.2% in those of the child-only group; 60% of children of the parent-only group, compared with only 31% of children of the child-only group, were in a non-obese status. seven years after program termination, two (6.6%) of the girls from the child-only group reported eating disorder symptoms (both bingeing and purging); none of the children in the parent-only group reported any eating disorder symptoms. family-based programs require the family to be involved. with more families having both parents in the workforce, present-day parents are less available to their children, which makes it difficult for children and adolescents waiting for them to provide a source of physical activity, to engage them in physical activity, or to accompany them to physical activity. parents are less able to enroll in family-based weight management programs if their work schedules conflict with their ability to use free time to participate. 78 interventions targeting overweight and obese children and adolescents that require a large time commitment, a commitment from family members, travel to the intervention location, and potential cost may be poorly received and underutilized. solutions to some of these challenges could be reached with innovative restructuring, telehealth, or a mixed model that may evolve over time. accordingly, researchers collaborated to examine whether utilizing a school nurse delivered intervention for overweight and obese adolescents would be feasible and acceptable, and whether it would serve to improve common obesogenic behaviors (selected for intervention) while positively impacting bmi. 78 clearly there are potentially modifiable behaviors that are associated with improving overweight and obesity. these include decreasing fast food intake, the amount of screen time, on and off dieting, depressive symptoms, low self-esteem, and weight teasing, on the one hand, as well as increasing fruit and vegetable intake through home availability and having more family meals, plus participating in moderate to vigorous physical activity. 79 they are the behaviors most targeted in nutrition interventions using medical nutritional therapy (mnt) by an rd as part of a comprehensive weight management program. increased frequency of rd visits has been associated with improved bmi outcomes in obese youth participating in these programs: "the probability of success exceeded 78% with one rd visit per month versus 43% with minimal rd exposure." 80 both the choose myplate and the 5-2-1-0 education initiatives target these potentially modifiable behaviors. in conjunction with each other, they can have a synergistic effect. healthcare professionals can use these tools together to impact behavior change sessions and establish simple lifestyle goals. many adolescents engage in extreme weight control behaviors and that number has greatly increased over time, as innumerable studies have shown. one population-based survey of adolescents attending middle and high schools in 1998à99 and again in 2008à09 by project eating and activity among teens and young adults assessed personal, psychological, behavioral, and socio-environmental factors believed to play a role in obesity. it showed that informing adolescents and young adults that increased dieting is associated with the persistence of obesity may help motivate adolescents to use more healthful means of weight management. 81, 82 this study reemphasizes the crucial importance of promoting healthy eating, improving the quality of the home food environment, and increasing physical activity as a means of preventing unhealthy weight loss behaviors. the weight management and healthy living 2015 survey from the hartman group 83 found that consumers are more interested in lasting changes and lifelong healthy eating than in crash dieting. it demonstrated that a campaign like myplate, with its message that individuals can achieve a healthier weight by eating more of some foods and less of others, can have utility in helping consumers make lifestyle changes that prove formidable. studies on energy density by b. j. rolls suggest that decreasing energy density reduces energy intake, independent of the macro nutrient mix, because of effects on satiety. 84 the indication is that diets of low energy density, which are typically rich in vegetables, fruits, legumes, and minimally processed grain products, allow individuals to consume "satisfying portions of food," while simultaneously reducing their energy intake. 84 this concept has been used in her best-selling book series volumetrics and made into a diet plan. 85 another approach which has been used in many interventions is the "traffic light" or "stoplight diet," which groups foods based on their nutrient quality and calorie density such that "red foods" should be consumed rarely, "yellow foods" infrequently, and "green foods" most often. 27 it is predicated on the idea that children can learn to substitute lower energy-dense healthy foods for less healthy higher energy-dense foods and that parents can facilitate this transition via increasing access to healthy foods and decreasing access to less healthy foods by altering food purchasing and food storage habits for the family at large. 86 the vast number of children and adolescents in the united states attend public schools. health and wellness policies and programs have traditionally been an important part of the daily curriculum of the majority of these schools. during the 20th century, mandatory physical education classes and nutrition programs, including the national school lunch program (nslp) and the school breakfast program (sbp), were implemented to address problems including "food insecurity." the current obesity epidemic among children and adolescents in the united states has stimulated the further involvement of local, state, and federal agencies in an attempt to use public schools as a venue to combat this problem. in 2004, the u.s. federal government mandated that all school districts participating in the federal meal program create a school wellness program by establishing a committee that includes individuals impacted by this problem. legislation also required the development of nutrition standards for meals and snacks served in schools, as well as the setting up of goals for physical education. the healthy hunger-free act, passed in 2010, required school districts to measure policy implementation and make these results publicly available. what follows here is a look at the impact of some of these and other programs implemented by the schools. approximately 12.2 million public school students from low-income homes are provided a nutritious breakfast as part of the federal school breakfast program (sbp), which was established in 1966 and permanently authorized in 1975. studies have shown that this may be associated with improved academic performance and a reduction in the number of students affected by food insecurity. 87, 88 the number of students participating in the sbp is less than half of those participating in the national school lunch program (nslp). to increase participation in the sbp, the federal government allows school districts to serve breakfast in the classroom (bic). 89 in new york city, more than 70% of public-school students qualify for free or reduced-price meals. researchers reported in 2013 on the impact of bic on the percentage of children going without morning food, the number of locations where food was consumed, and the estimated calories each child consumed. comparisons were made between schools that offered bic and those that did not. results showed that students in bic schools were significantly more likely to eat more than once in the morning and, on average, ate an estimated 95 additional calories each morning. 89 a similar study in the philadelphia public school system, completed and another approach which has been used in many interventions is the "traffic light" or "stoplight diet," which groups foods based on their nutrient quality and calorie density such that "red foods" should be consumed rarely, "yellow foods" infrequently, and "green foods" most often. 27 approximately 12.2 million public school students from lowincome homes are provided a nutritious breakfast as part of the federal school breakfast program (sbp), which was established in 1966 and permanently authorized in 1975. studies have shown that this may be associated with improved academic performance and a reduction in the number of students affected by food insecurity. 87, 88 published in 2018, found that bic did not affect the combined incidence of overweight and obesity among public school students. 90 however, an increasing incidence and prevalence of obesity among the students was noted. in 2003, arkansas became one of the first states to pass legislation to specifically address the epidemic of obesity. it required annual body mass index (bmi) screenings for all public school students, elimination of elementary school students' access to vending machines, and creation of physical education and nutrition standards via district physical activity and nutrition committees along with input from a child health advisory committee. 91, 92 a study published in 2018 assessing the effectiveness of this policy concluded that it was very unlikely that the arkansas act was having an impact on preventing adolescent overweight and obesity. 93 california began bmi screening during the early part of the first decade of the 21st century. the state collected bmi data annually on fifth, seventh, and ninth grade students. parental notification of the results was optional. in 2001, bmi results were sent to 35% of parents or guardians, which rose to 52% in 2008. notification in fifth and/or seventh grade on subsequent bmi z scores, when compared to no notification, showed no significant difference in reducing the prevalence of obesity among this population of students. 94 one state that offered a program that achieved better success is massachusetts. in a pair-matched, cluster-randomized, and controlled school-based trial using a convenience sample of six public high schools, eligible 9th to 11th graders were recruited to participate in "lookin good feelin good," a school nurse-delivered counseling intervention with one-on-one sessions conducted over two months during the school day, during non-academic classes held in the privacy of the school nurse's office. 95 the 5-3-2-1-0 approach was used "to support making five behavioral changes" by utilizing cognitive behavioral techniques to facilitate changes in selfmanagement behaviors through health knowledge and the development of positive outcome expectations, self-control, and behavioral capacity skills and self-efficacy." targeted adolescents completed behavioral and physiological assessments at baseline, and at 2-month and 6-month follow-ups. at two months, compared to control participants, this intervention was able to impact both increased intake of breakfast, and decreased total sugar and added sugar intake. while these particular positive results were not maintained at further follow-up, other positive outcomes were noted at 6 months when the adolescents in the intervention were more likely to drink soda less than or equal to one time a day and eat at fast food restaurants less than or equal to one time per week compared to controls. total calorie intake and calories from fat did not change significantly between groups. screen time and time spent in moderate to vigorous physical activity were not statistically affected. although there was no statistically significant difference in bmi, students in the counseling intervention schools experienced favorable improvements in their bmi compared to students in the control schools. 95 there are clear factors standing in the way of more successful outcomes. an online survey of u.s. public school administrators completed in 2016 indicates that rarely are evidence-based obesity prevention programs being implemented. 92 many programs focus on students' weights rather than on healthy lifestyles. barriers to implementation include lack of funding, time, and training. the johns hopkins evidence-based practice center completed a study of 124 school-based interventions in 2013 and reported on two kinds of programs that demonstrated high evidence of effectiveness in preventing overweight and obesity in the schoolaged population. these are (1) school-based programs that combined physical activity and diet with a home-based component and (2) school-based physical activity and diet interventions that were combined with a home and community component. 96 medication is only recommended after an unsuccessful attempt at weight loss that includes the adoption of a healthy and age-appropriate diet and an increase in daily physical activity. presently, five medications are approved for adults in the united states for long-term management of obesity. 97, 98 weight loss associated with these ranges from approximately 3%à9%. side effects and adverse reactions are common with each. for adolescents greater or equal to twelve years of age, the only prescription medication approved by the united states food and drug administration (usfda) is orlistat. no medication is approved for use in children less than twelve years of age. [99] [100] [101] orlistat is a lipase inhibitor that blocks the absorption of fat. it is recommended to be taken with each meal. although it has been demonstrated to have a good safety profile, side effects can include cramping, excessive gas, oily spotting, fecal urgency, and abdominal pain. since these side effects occur not infrequently, it can be difficult to maintain compliance with this medication. studies have shown modest weight loss efficacy when orlistat is used along with a comprehensive weight loss program. in the largest study (n = 539) of orlistat use in combination with diet, exercise, and behavioral modification, a bmi reduction of approximately 2.4%, as compared to a placebo group, was seen over a treatment period of one year. 102 the only cardiometabolic benefit seen was a small reduction in diastolic blood pressure. at the present time there are no studies reporting long-term outcomes after cessation of orlistat use. phentermine, a norepinephrine reuptake inhibitor, has been approved by the usfda for short-term use for ages seventeen or older. no randomized clinical trials of phentermine have been conducted in individuals younger than seventeen years. common side effects observed in adults using this medication include rapid heart rate, high blood pressure, anxiety, insomnia, and headache. metformin, a biguanide used predominately for glycemic control in individuals with type 2 diabetes mellitus, has been studied for use in treatment of pediatric obesity along with lifestyle interventions. 103 it does not have usfda approval for this use in children and adolescents at the present time. one systematic review of the benefits and risks of using metformin in treating obesity in this population demonstrated a statistically significant, but very modest, reduction in bmi when combined with lifestyle interventions over the short term. no serious adverse events were reported to occur among individuals in the review. the authors concluded that metformin has not been shown to be clinically superior to other options for treating childhood obesity in the short term. bariatric surgery has become an optional treatment for adolescents who are severely obese. in 2004, an expert panel of pediatric surgeons and pediatricians made recommendations regarding selection criteria for bariatric surgery in individuals less than eighteen years of age. 104 selection criteria included: (1) failed >6 months of organized attempts at weight management, (2) has attained or nearly attained physiologic maturity, (3) >50 bmi, or >40 bmi with an associated severe co-morbidity (i.e. sleep apnea, diabetes, hypertension), (4) demonstrates commitment to comprehensive medical and psychological evaluations both before and after surgery, (5) agrees to avoid pregnancy for at least a year, (6) is capable of and willing to adhere to nutritional guidelines postoperatively, (7) provides informed consent, (8) demonstrates decisional capacity, (9) has a supportive family environment, and (10) surgery would be done in centers that have experience with bariatric surgery and a team of specialists trained to provide long-term follow-up care of the metabolic and psychosocial requirements of the patient and family. as an ancillary study of its observational study of adults undergoing bariatric surgery, the national institute of diabetes and digestive and kidney diseases (nddk) created teen-longitudinal assessment of bariatric surgery (teen-labs). funding was provided to five centers in the united states to enroll at least 200 adolescent bariatric surgical patients to serve as a prospective observational cohort study aimed at assessing the clinical, epidemiological, and behavioral parameters in a select population of adolescents undergoing bariatric surgery. 105 the majority of surgical procedures completed in the study were either gastric bypass (roux-en y), which creates a small gastric pouch that is connected directly to the jejunum, bypassing the upper portion of the small intestine, or the sleeve gastrectomy, which creates a narrow stomach pouch and removes the rest of the stomach. for adolescents greater or equal to twelve years of age, the only prescription medication approved by the united states food and drug administration (usfda) is orlistat. no medication is approved for use in children less than twelve years of age. [99] [100] [101] research published in 2018 has shown an increasing use of vertical sleeve gastrectomy compared to other surgical procedures. 106 multiple publications from the teen-labs study have documented that severely obese adolescents undergoing bariatric surgery, when compared to matched adolescents undergoing medical treatment alone, had better weight loss, improvement in cardiovascular risk markers and better glycemic control. the teen-labs researchers also reported identified risks including specific micronutrient deficiencies and the need for an acceptable rate (13%) of additional abdominal procedures. [107] [108] [109] [110] [111] overall similar findings were obtained by olbers in a prospective nationwide study of 81 swedish adolescents who were severely obese and underwent roux-en y gastric bypass. 112 a single study completed by alqalhtani in saudi arabia reviewed the effects of laparoscopic sleeve gastrectomy in 114 children younger than 14 years of age (mean § sd, 11.2 § 2.5 years). it was concluded that the procedure resulted in significant weight loss, improved growth, and a resolution of comorbidities, without mortality or significant morbidity. teen-labs researchers recently compared 5-year outcomes of gastric bypass in adolescents with those of adults. they reported that adolescents and adults who underwent gastric bypass surgery had similar significant weight loss 5 years after surgery, but adolescents had a higher rate of remission of hypertension and diabetes following gastric bypass than adults. they also found that abdominal operations and short-term nutritional deficiencies were more common among adolescents than adults following surgery. 113 data from another teen-lab study demonstrated that joint pain, physical function, and health-related quality of life improved after bariatric surgery. 114 in 2018, the american society for metabolic and bariatric surgery's (asmba) pediatric committee updated their recommendations for metabolic and bariatric surgery in children and adolescents following a comprehensive literature search. they proposed that metabolic and bariatric surgery is indicated for the following adolescents: (1) bmi >35 or 120% of the 95th percentile with clinically significant comorbidities (whichever is lower), and (2) bmi >40 or 140% of the 95th percentile (whichever is lower). in addition, the patient and family should demonstrate the ability and motivation to adhere to recommended pre-and postoperative treatment. the asmba's recommendations regarding contraindications for surgery included: (1) a medical correctable cause of obesity, (2) an ongoing substance abuse problem (within the preceding year), (3) inability to adhere to postoperative dietary and medication regimens as a result of a medical, psychiatric, psychosocial, or cognitive condition, and (4) current or planned pregnancy within 12à18 months of the procedure. at the same time, their guidelines stated that treatment should not be denied to those adolescents with cognitive disabilities, a history of mental illness, a history of eating disorders that are treated, immature bone growth or low tanner stage. their overall conclusion was that surgery was safe and effective in adolescents, and that early intervention can reduce the risk of persistent obesity as well as end organ damage from longstanding comorbidities. 115 multiple publications from the teen-labs study have documented that severely obese adolescents undergoing bariatric surgery, when compared to matched adolescents undergoing medical treatment alone, had better weight loss, improvement in cardiovascular risk markers and better glycemic control. in 2018, the american society for metabolic and bariatric surgery's (asmba) pediatric committee updated their recommendations for metabolic and bariatric surgery in children and adolescents following a comprehensive literature search. they proposed that metabolic and bariatric surgery is indicated for the following adolescents: (1) bmi >35 or 120% of the 95th percentile with clinically significant comorbidities (whichever is lower), and (2) bmi >40 or 140% of the 95th percentile (whichever is lower). the american academy of pediatrics, as well, has issued guidelines in a policy statement entitled "pediatric metabolic and bariatric surgery: evidence, barriers and best practices," published in 2019. 116 they recommended considering the following factors in deciding on surgery: (1) shared decision-making including patient, parents, medical and surgical providers, (2) bmi and comorbidity, (3) physiological, psychological, and developmental maturity, (4) ability to understand risks and benefits and be able to adhere to lifestyle modifications, (5) decision-making capacity, (6) robust family and social supports before and after the procedure. concluding that there was no evidence to support the application of age-based eligibility, the aap set forth the following indications for adolescent metabolic and bariatric surgery: (1) class 2 obesity: bmi i 35 or 120% of the 95th percentile for age and sex, whichever is lower, and with an associated clinically significant disease, including obstructive sleep apnea (ahi >5), t2dm, increased intracranial hypertension, nash, blount disease, scfe, gerd, and hypertension, and (2) class 3 obesity: bmi 40, or 140% of the 95th percentile for age and sex, whichever is lower without any associated comorbid conditions. multicomponent programs that focus on diet, behavior-change, and physical acitivity are recommended as the first line of treatment for children and adolescents who are overweight or obese. treatment should be guided by the patient's developmental, cognitive, and pubertal stage of development. the range of clinicians and environments providing these services is extensive with most services being provided through multidisciplinary tertiary care clinics and providers. these interventions have been proven to be beneficial in achieving small short-term reductions in bmi. presently, there is both a lack of long-term benefit and evidence that these interventions will reduce the incidence of obesity or the associated cardio-metabolic complications for children and adolescents (and adults) in the future. an almost universal consensus recommends a significant increase in research on all interventions including minority and special-needs populations with coordinated long-term follow-up. school-based programs, pharmacotherapy, and bariatric surgery are additional approaches that are increasingly being utilized for weight loss management; of these, 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surgery asmbs pediatric metabolic and bariatric surgery guidelines pediatric metabolic and bariatric surgery: evidence, barriers, and best practices key: cord-017131-rx1z4orm authors: patra, amlan kumar title: an overview of antimicrobial properties of different classes of phytochemicals date: 2012-02-18 journal: dietary phytochemicals and microbes doi: 10.1007/978-94-007-3926-0_1 sha: doc_id: 17131 cord_uid: rx1z4orm plants produce a great diversity of phytochemicals, the beneficial properties of which have been used by humans for centuries since the advent of human civilization. with the discovery of effective and potent antimicrobial compounds, these synthetic antimicrobial compounds are widely used to prevent and cure microbial diseases. however, the development of antibiotic resistant strains of bacteria, reduced efficacy and safety of antimicrobials and the search of new antimicrobials against emerging incurable diseases by conventional antimicrobial agents have revived to explore phytochemicals as an alternative to synthetic antimicrobial compounds. although numerous studies have been conducted in vitro and in vivo in the recent years on the efficacy of plant phytochemicals as antimicrobial agents, this chapter provides an overview of the antimicrobial properties of some major group of phytochemicals, namely, different phenolic compounds, alkaloids, saponins, iridoids and secoiridoids, polyacetylenes, glucosinolates, terpenoids, sulfinate, limonoids (tetranortepenoids) and anthranoids against pathogenic bacteria, fungi, viruses and commensal bacteria in the intestinal tracts of humans and animals. this chapter also discusses their antimicrobial mechanisms of action, the efficiency of different groups of phytochemicals against multiple-drug resistant bacteria, the effect of active dietary phytometabolites on the beneficial and pathogenic microbes of the gastrointestinal tracts and the outcomes of combination of phytofactors and drugs interactions. plants contain a wide array of phytochemicals , which have traditionally been utilized for centuries in folk medicines or ethnomedicines. the earliest information on the medicinal use of plants comes from china in 5000 bc (greathead 2003 ) , from india (in rigveda and atharvaveda) in 2000 bc (ramawat et al. 2008 ) , from mesopotamia in 2600 bc (newman et al. 2000 ) , and also from egypt in about 1550 bc (davidson and naidu 2000 ) . the natural medicines were widely used until the fi rst half of the twentieth century, when a shift towards synthetic medicines that were more effective, patentable and highly profi table, occurred (tyler 1999 ) . however, there have been increasing interests towards use of natural chemicals in medicinal purposes in recent years. these ethnomedicines are encouraging for both the public and national health care institutions as alternatives to synthetic drugs due to relatively lower incidences of adverse reactions compared to modern conventional pharmaceuticals along with their reduced cost (nair et al. 2005 ) . recently, the growing occurrences of multi-drug resistant strains of bacteria and the appearance of strains with decreased susceptibility to antibiotics have led to a resurgence of research interests in the discovery of novel antimicrobial agents from natural sources for therapeutic and preventive purposes against microbial diseases, food preservatives and feed additives in the animal industry. the ethnopharmacologists, botanists, microbiologists and natural-product chemists are constantly in search of medicinal effi cacy of plants and their phytochemicals , since the reported data so far available on plants are comparatively meager compared to the vast number of plant population. plants produce a great diversity of compounds. the structures of close to 50,000 compounds have already been elucidated and there are perhaps hundreds of thousands of such compounds in plants (pichersky and gang 2000 ) . only a few of these are part of 'primary' metabolic pathways (those common to all organisms). the rest are secondary metabolites or phytochemicals whose biosynthesis is restricted to selected plant groups (pichersky and gang 2000 ) . phytochemicals can be divided into many major classes depending upon the chemical structures, botanical origins, biosynthesis pathways or biological properties. the most phytochemical classifi cation scheme is based on chemical structures such as phenolics, alkaloids, saponins, terpenoids, limonoids, polyacetylenes and secoiridoids and so on. numerous studies have been conducted in vitro and in vivo in the recent years on the effi cacy of plant phytochemicals as antimicrobial agents. this paper presents the antimicrobial properties of some major group of phytochemicals against pathogenic bacteria, fungi and virus, and benefi cial microbes of the gastrointestinal tracts and their mechanism of action. phenolic compounds are a group of phytochemicals , which have a phenol structure, i.e. an aromatic benzene ring bearing at least one hydroxyl substituent (robbins 2003 ; vermerris and nicholson 2006 ) . phenolic compounds are commonly found 1 an overview of antimicrobial properties of different classes of phytochemicals throughout the plant kingdom, where they protect the plants from microbial infections, ultraviolet radiation and chemical stressors. this large and diverse group of phytochemicals is classifi ed into many subclasses depending upon chemical structures and occurrence in plants. the commonly categorized subclasses of phenolic compounds are simple phenolics (resorcinol and phloroglucinol ), phenolic acids and aldehydes , coumarins , fl avonoids , chalcones , aurones , benzophenones , xanthones , stilbenes , benzoquinones , naphthaquinones , anthraquinones , betacyanins , lignans , and polyphenols (proanthocyanidin , galloyl, hexahydroxydiphenyl ester , hydroxy cinnamic acid , and phloroglucinol derivatives) (vermerris and nicholson 2006 ; handique and baruah 2002 ) . the detailed structures and chemistry of these phenolic compounds are presented elsewhere (vermerris and nicholson 2006 ) . foods containing phenolics are becoming an important part of diets due to their potential anti-oxidative properties. besides, these compounds have also potent anti-microbial properties. the phenolic acid and aldehyde group of phenolic compounds is characterized by the presence of a carboxylic acid or aldehyde group substituted on a phenol (table 1. 1 ; vermerris and nicholson 2006 ) . the naturally occurring phenolic acids generally have two characteristic constitutive carbon frameworks: the hydroxycinnamic and hydroxybenzoic structures (robbins 2003 ) . majority of cinnamic and benzoic acid derivatives in plants are linked through ester, ether or acetal bonds to structural components, polyphenols , organic acids (quinic , maleic , tartaric and shikimic acid ), glucose and terpenes (robbins 2003 ) . chlorogenic acid is an ester of quinic acid and caffeic acid . some aldehyde analogues of phenols (e.g. vanillin ) are also grouped with phenolic acids (robbins 2003 ) . the numbers and positions of the hydroxyl and other groups on the aromatic ring can produce a large number of compounds in this subclass (robbins 2003 ; vermerris and nicholson 2006 ) . phenolic acids are present in a wide range of plants including in many common foods such as tea, coffee and berries. besides, phenolic acids and aldehydes could be formed by the intestinal microbial biotransformation of other phenolic compounds in the intestine, where they may infl uence intestinal microbiota. a number of simple phenols and phenolic acids possess antibacterial, antiviral and antifungal activities against a wide range of microbes, but at different concentrations. gallic acid and p -hydroxybenzoic acid reduced the viability of camplylobacter jejuni at concentrations as low as 1 mg/l (ganan et al. 2009 ) . synaptic acid , vanillic acid , and caffeic acid were microbicidal at concentrations starting at 10 mg/l. ferulic acid and cumaric acid were effective at a concentration of 100 mg/l (ganan et al. 2009 ) . ozçelik et al. ( 2011 ) recently tested some phenolic acids such as gallic acid, caffeic acid, chlorogenic acid , and quinic acid for their in vitro antiviral, antibacterial, and antifungal activities. all these phenolic acids were inhibitory to herpes simplex virus type 1 (hsv -1), whereas gallic acid, chlorogenic acid and quinic acid showed potent antiviral effect against parainfl uenza virus type 3 at the therapeutic range of 0.8-0.05 mg/l. in general, antibacterial activity of phenolic acids is stronger against gram-positive bacteria than gram-negative bacteria (merkl et al. 2010 ; cueva et al. 2010 ) . the outer membrane of gram-negative bacteria provides them with a hydrophobic surface structure that is able to exclude certain hydrophilic molecules, making them inherently resistant to many antimicrobial agents including phenolic acids (alakomi et al. 2007 ; cueva et al. 2010 ) . gram-positive bacteria are enclosed in a plasma membrane covered by a thick peptidoglycan wall and lack an outer membrane (alakomi et al. 2007 ; cueva et al. 2010 ) . although, phenolic acids are effective against gram-negative bacteria, their antimicrobial effect is strain dependent (e.g. different strains of escherichia coli ; cueva et al. 2010 ) . phenolic compounds are usually poorly absorbed in the small intestine, and thus most of the dietary phenolics accumulate in the colon (clifford 2004 ; van duynhoven et al. 2011 ) . therefore, higher concentrations of phenolic acids may reach in the intestine than the concentrations in diets. phenolics may selectively suppress or stimulate (tzounis et al. 2008 ) . chlorogenic, quinic and gallic acids stimulated growth of lactobacillus collinoides relative to control cultures (no additive) up to concentrations of 1 g/l of tomato broth media. in contrast, growth of lactobacillus brevis was little affected during early incubation, which has been suggested to be due to metabolism of these acids (stead 1994 ) . from structure-activity relationship , phenols having different alkyl chain length with hydroxyl groups could be important for antimicrobial actions (kubo et al. 1995 ) . p-hydroxybenzoic acid, protocatechuric , gentisic acid , vanillic acid , ferulic acid , caffeic acid and their methyl, ethyl, propyl and butyl esters were investigated for antibacterial action. it has been reported that the antimicrobial effect of phenolic acids derivatives increased with the increasing length of the alkyl chain (merkl et al. 2010 ) . the presence of hydroxyl groups on the phenol groups and oxidized status of phenol groups also determine the toxicity of microbes. the fl uidity of the cell membrane could be disturbed with increasing hydrophobic alkyl chains. the phenolic acids could enter the molecular structure of the membrane with the polar hydroxyl group oriented into the aqueous phase by hydrogen bonding and nonpolar carbon chain aligned into the lipid phase by dispersion forces (kubo et al. 1995 ) . thus, when the hydrophilic force exceeds hydrophobic one, the activity tends to disappear. also, the number and position of substitutions in the benzene ring of the phenolic acids and the saturated side-chain length infl uenced the bacteriocidal effects of phenolic acids against the different microorganisms, but in different ways against gram-positive and gram-negative bacteria (cueva et al. 2010 ) . for example, cueva et al. ( 2010 ) showed that for benzoic and phenylacetic acids, e. coli was inhibited in the following order of potency: non-substituted > 4-hydroxy-3-methoxy-> 3-hydroxy-> 4-hydroxy-> 3,4-dihydroxy-substituted acid. for phenylpropionic acids, the order differed slightly: nonsubstituted > 4-hydroxy-> 3-hydroxy->3,4-dihydroxysubstituted acid. however, the potency of phenolic acids was in different order for lactobacillus spp. for benzoic acids, the order of potency was: 4-hydroxy-> 3-hydroxy-> non-substituted > 4-hydroxy-3-methoxy-> 3,4-dihydroxy-substituted acids, except for lactobacillus coryniformis cect 5711 (4-hydroxy-> non-substituted > 3-hydroxy > 4-hydroxy-3methoxy-substituted acids). for phenylacetic acids, growth inhibition of lactobacilli was on the order of non-substituted > 3-hydroxy-> 4-hydroxy-> 3,4-dihydroxysubstituted acids. for phenylpropionic acids, growth inhibition was as follows: nonsubstituted > 4-hydroxy-> 3-hydroxy > 3,4-dihydroxy-substituted acids, except for lactobacillus fermentum cect 5716 (3-hydroxy > non-substituted > 4-hydroxyand 3,4-dihydroxy-substituted acids) and lactobacillus plantarum lch17 (nonsubstituted > 3-hydroxy-> 4-hydroxy-> 3,4-dihydroxy-substituted acids). coumarins are naturally found in many families of plants (apiaceae, asteraceae, fabiaceae, rosaceae, rubiaceae, rutaceae and solanaceae) and microorganisms, and approximately 1,000 coumarins have been isolated from these sources (weinmann 1997 ; smyth et al. 2009 ) . coumarins can be classifi ed into fi ve groups depending upon the structure, i.e. coumarins with substituents in benzene ring, coumarins with substituents in pyrone ring, furocoumarins, pyranocoumarins , and coumarin dimmers ( fig. 1.1 ; smyth et al. 2009 ) . coumarins exhibit a broad diversity for antimicrobial activity. o-acetylcolumbianetin, edultin, cniforin a, columbianadin and imperatorin isolated from the fruits of cnidium monnieri (l.) cuss exerted a little to no appreciable growth-inhibition of gram-positive and gram-negative bacteria (ng et al. 1996 ) . an amino-coumarin -7-amino-4-methylcoumarin showed broad-spectrum antibacterial and antifungal activities (liu et al. 2008 ) . melliou et al. ( 2005 ) studied the antibacterial activity of pyranocoumarins using an agar disc diffusion method. seselin, xanthyletin, 5-hydroxyseselin, and 7-hydroxyalloxanthyletin had no antibacterial effects. coumarin derivatives such as 5-methoxyseselin and its brominated derivatives, alloxanthoxyletine, the acetylated derivatives, and dipetalolactone were active against all the tested bacteria. a seselin derivative, 3-bromo-4-benzoyloxyseselin showed moderate activity, while three coumarins containing acetoxy groups in pyrano ring were only active against the two gram-positive bacteria. a new coumarin -cajanuslactone isolated from pigeon pea leaves showed anti-bacterial activity against staphylococcus aureus (atcc 6538), and the minimum inhibitory concentration (mic) and the minimum bactericidal concentration (mbc) were 0.031 and 0.125 mg/ml, respectively . some seselin derivatives, including derivatives of 5-methoxyseselin, were found to be potent against human immunodefi ciency virus (hiv ) (xie et al. 1999 ) . it has been suggested that the presence of oxygenated substituents in the ether or ester form usually enhances the antibacterial activity, while the presence of free hydroxyl group reduces the activity (melliou et al. 2005 ) . this fact could be at least partially attributed to the reduced lipophilicity of the hydroxyl derivatives, which hinders the penetration through the bacterial cell wall (melliou et al. 2005 flavonoids are one of the largest groups of secondary metabolites that are distributed in various plant species. they have signifi cant antioxidant properties, which are benefi cial for health. these polyphenolic compounds are constructed basically with an a and c ring of benzo-1-pyran-4-quinone and a b ring. the main classes of fl avonoids ( fig. 1.2 ) (having a hydroxyl group at the 3-position), e.g. kaempferol , quercetin , galangin , datiscetin , morin , robinetin , isorhamnetin , tamarixetin , quercetagetin and myricetin ; (3) fl avanones (2-3 bond saturated), e.g. hesperetin , taxifolin, eriodictyol and naringenin ; (4) flavan-3-ol, e.g. catechin and epicatechin; (5) isoflavone , e.g. genistein , daidzein and coumestrol ; (6) anthocyanidins : cyanidin , delphinidin , pelargonidin and peonidin (crozier et al. 2006 ) . the majority of fl avonoids commonly remain conjugated with sugars as glycosides . numerous fl avonoid derivatives showed antiviral activity against a wide range of viruses such as hsv , hiv , coxsackie b virus, coronavirus, cytomegalovirus, poliomyelitis virus, rhinovirus, rotavirus, poliovirus, sindbis virus, and rabies virus (de bruyne et al. 1999 ; evers et al. 2005 ; nowakowska 2007 ) . ozçelik et al. ( 2011 ) investigated the effects of quercitin, apigenin, genistein , naringin, silymarin and silibinin against hsv -1 and pi-3 virus. all fl avonoids inhibited hsv -1 activity, but only genistein inhibited parainfl uenza type-1 (pi-1) activity. of the three fl avonoids (baicalin, rutin and naringin) examined by ng et al. 1996 , baicalin was found to be the most potent in inhibiting the growth of s. aureus : 11 of the 16 strains tested were inhibited at 128 mg/l. however, no inhibitory activity of rutin and naringin against s. aureus was observed at 128 mg/l. at this concentration, naringin and baicalin inhibited two strains and rutin inhibited one strain of the eight p. aeruginosa strains tested. the fl avonoids compounds display different mode of antiviral action. for instance, baicalein probably block human cytomegalovirus infection at entry level while the primary mechanism of action for genistein may be to block immediateearly protein functioning off human cytomegalovirus (evers et al. 2005 ) . both these fl avoinoids did not inhibit the virus replication (evers et al. 2005 ) . puupponen-pimia et al. ( 2001 ) investigated 13 falovonoid compounds (apigenin, (+)-catechin , chlorogenic acid , cyanidin chloride, delphinidin chloride, isoquercitrin, kaempferol , cyanidin-3-glucoside (kuromanin), luteolin, myricetin , pelargonidin chloride, quercetin dehydrate and rutin trihydrate), and 4 phenolic acids (caffeic acid , 3-coumaric acid, ferulic acid , trans-cinnamic acid) on 7 gram-positive lactic acid bacteria of intestines, gram-negative e. coli cm 871 and salmonella . myrecetin strongly inhibited the growth of lactobacillus as well as e. coli , but did not affect salmonella . luteolin was weakly inhibitory to gram-positive lactic acid bacteria but not to gram-negative bacteria. the anthocyanidins pelargonidin, delphinidin and cyanidin, as well as cyanidin-3-glucoside, only inhibited growth of e. coli and had no effect on other bacterial strains (puupponen-pimia et al. 2001 ) . however, phenolic acids did not inhibit lactic acid bacteria, but inhibited gram-negative e. coli and salmonella sp. hatano et al. ( 2005 ) discussed that some prenylated fl avonoids such as licoricidin (an isofl avan) effectively suppressed the antibiotic resistance of methicillin-resistant s. aureus (mrsa ) compared to other fl avonoids. the addition of 4 m g/ml of licoricidin shifted the mic of oxacillin from 128-256 to 8-16 m g/ml, and 8 m g/ml of licoricidin reduced it to less than 0.5 m g/ml. the requirement for dimethylallyl or equivalent substituents suggests the importance of affi nity for the bacterial cell membrane. 1 an overview of antimicrobial properties of different classes of phytochemicals phenolic acids show greater antimicrobial potency than their corresponding fl avonoids precursors such as the monomers (+)-catechin and (−)-epicatechin (ganan et al. 2009 ; cueva et al. 2010 ) . therefore, microbial transformations of dietary fl avonoid compounds in the intestine could lead to more potent microbialinhibitory compounds (phenolic acids ) and could reach greater concentrations in the intestine. this may selectively infl uence intestinal bacteria species, and therefore could affect the diversity and metabolic activity of the intestinal microbiota, including the transformation of phenolics in the gut (cueva et al. 2010 ) . epigallocatechin gallate exerted strong antibacterial growth against gram-positive bacteria than against gram-negative bacteria (yoda et al. 2004 ; engels et al. 2009 ) . it has been stated that gram-positive bacteria absorb more epigallocatechin gallate into their peptidoglycan cell wall and aggregate its presence, while gram-negative bacteria do not aggregate and absorb less epigallocatechin gallate (ikigai et al. 1993 ; engels et al. 2009 ) because of the repulsive negative charge of lipopolysaccharides on the surfaces of gram-negative bacteria. the binding of epigallocatechin gallate to peptidoglycan disrupts its function in osmotic protection, cell division, and cell wall biosynthesis (yoda et al. 2004 ) . detailed information of antimicrobial activities of fl avonoids has been discussed elsewhere in this book (chap. 2 ). some phenolic acids (ellagic and gallic acids) or fl avonoids (fl avan-3-ol, fl avan-3-4-diol or fl avan-4-ol) in plants are esterifi ed or polymerized into dimeric, oligomeric or polymeric compounds. most abundantly present polyphenolic compounds in plants are tannins , which are usually of two types: hydrolysable tannins (ht) and condensed tannins (ct ). the ht are complex molecules with a polyol as a central core such as glucose, glucitol, quinic acids, quercitol and shikimic acid that is partially or totally esterifi ed with a phenolic group, i.e. gallic acid (3,4,5-trihydroxy benzoic acid ; gallotannins) or gallic acid dimmer hexahydroxydiphenic acid (ellagitannins) (haslam 1989 ) . the ct (proanthocyanidins) are mainly polymers of the fl avan-3-ols (epi)catechin and (epi)gallocatechin units, which are linked by c4-c8 and c4-c6 interfl avonoid linkages (ferreira et al. 1999 ; hagerman and butler 1989 ) . the polyphenols also exert a wide range of antibacterial and antifungal activities. ellagitannin extracts inhibited a range of pathogenic organisms including vibrio cholerae , shigella dysenteriae and campylobacter spp . (silva et al. 1997 ; puupponen-pimia et al. 2002 ) . puupponen-pimia et al. ( 2005 ) reported that berry extracts exhibit selective inhibitory properties against intestinal bacteria such as staphylococcus , salmonella , listeria and lactobacillus strains, and the selective inhibitory actions varied with berry extracts. in general, pathogenic staphylococcus and salmonella were sensitive to various berry extracts and ellagitannins fractions, while pathogenic listeria and benefi cial lactobacillus were not inhibited. rauha et al. ( 2000 ) studied antimicrobial effects of some berry extracts against food spoilage and poisoning bacteria. the widest antibacterial activity was present in berries belonging to the genus rubus (cloudberry and raspberry) that are rich in ellagitannins. ellagic acid has been reported to exhibit a dose-dependent inhibitory effect (ic50 = 1 mm) on helicobacter pylori isolated from peptic ulcer patients (chung 1998 ) . tannins isolated from dichrostachys cinerea roots exerted antimicrobial effects against s. aureus , e. coli , shiegella spp. and p. aeruginosa with mic of the tannins ranging between 4.0 and 5.5 mg/ml, while the mbc ranging between 4.5 and 6.0 mg/ml (banso and adeyemo 2007 ) . gallotannins extracted from the mango seed kernel inhibited the growth of gram-positive food spoilage bacteria and decreased the growth of gram-negative e. coli , but did not affect lactic acid bacteria (engels et al. 2009 ) . the antibacterial properties of cranberry juice with inhibition of e. coli adherence to mucosal surfaces by cranberry juice is reported to be associated with the presence of proanthocyanidins (howell et al. 1998 ) . many polyphenols have antiviral activities against different types of viruses (de bruyne et al. 1999 ; cheng et al. 2002 ) . it has been suggested that prodelphinidin b-2 3 ¢ -o -gallate (a proanthocyanidin gallate isolated from green tea leaf) showed anti-hsv -2 properties with the mechanism of inhibiting the attachment and penetration between cells and viruses possibly through the instability of viral glycoproteins (cheng et al. 2002 ) . the structure and functional groups of the polyphenol compounds may determine the effectiveness of the antiviral activities (de bruyne et al. 1999 ) . the content of small-molecular phenolic compounds have greater infl uence on the antibacterial activity of extracts than tannins (nazaruk et al. 2008 ) . thus, polyphenols could be cleaved by bacterial enzymes to form a number of phenolic acids in the intestine, where they may infl uence the microbial populations (bock and ternes 2010 ) . engels et al. ( 2009 ) recently studied the effects of gallotannins with different galloyl units from mango seed kernel on various gram-positive and gram-negative bacteria. gallotannins showed antibacterial activities with mics ranging from 0.1 g/l for s. aureus to 3.3 g/l for pediococcus acidilactici . they also observed that degree of galloylation did not affect the growth of bacteria. it has been suggested that the antibacterial activities of gallotannins are due to their strong affi nity for iron and the inactivation of membrane-bound proteins (engels et al. 2009 ) . it has also been shown that gallotannins changed the morphology of bacillus subtilis , which has been hypothesized due to inhibition of cell division by binding of gallotannins to the cell wall or inhibition of enzymes involved in cell separation (engels et al. 2009 ) . naphthoquinones are widely distributed in plants, fungi, and some animals. lapachol, plumbagone, juglone and lawsone are naturally occurring naphthoquinones 1 an overview of antimicrobial properties of different classes of phytochemicals of plant origin that have antimicrobial effects against various pathogenic bacteria and fungi. adeniyi et al. ( 2000 ) reported that two dimeric naphthoquinones, diospyrin and isodiospyrin , isolated from the root of diospyros piscatoria (gurke), a common ingredient in several folk medicines, exhibited a broad spectrum of antibacterial activity against s. pyogenes and s. pneumoniae (mics of diospyrin ranged from 1.56 to 50 m g/ml) salmonella choleraesuis serotype typhi ( s. typhi ) and mycobacterium chelonae (mics of diospyrin were between 25 and 100 m g/ml). isodiospyrin was more active than its racemic isomer diospyrin (mics against gram-positive bacteria ranged from 0.78 to 50 m g/ml, while those against pseudomonas aeruginosa and s. typhi ranged from 50 to 100 m g/ml). another naphthoquinones, lapachol and b -lapachone, found in species of tabebuia, had relevant effects against candida albicans, candida tropicalis, and cryptococcus neoformans, and were more active than the reference standard, ketoconazole. lapachone showed strong antimicrobial activity than lapachol against the fungi (guiraud et al. 1994 ) . methanol extract from the dried inner bark of tabebuia impetiginosa exhibited potent antibacterial activity against h. pylori which contained lapachol and anthraquinones (park et al. 2006 ) . alkaloids have been defi ned as n-heterocyclic basic metabolites, although the defi nition does not clearly separate from other n-containing compounds. alkaloids have been classifi ed in many ways depending upon biogenic precursors or carbon skeleton characteristics. they have a great structural diversity compared with other classes of phytochemicals . alkaloids are generally known according to their carbon skeleton structures. pyridine (e.g. piperine), piperidine , quinoline , indole , pyrrolidine , quinazoline , isoquinoline , glyoxaline , lupinane , tropan , phenanthridine , imidazoline , alkaloidal amines and terpenoid types of alkaloids are commonly found in plants (hegnauer 1988 ) . alkaloid fractions isolated from strychnos potatorum l.f. (loganiaceae) seeds, which were of indole type, were tested for their antimicrobial properties against some pathogenic gram-positive, gram-negative and acid-fast bacteria and fungi. these fractions had shown considerable antimicrobial activity against both bacteria and fungi at the tested concentrations (100 and 200 m g/ml). further, the growth of proteus vulgaris , s. aureus , salmonella typhimurium, vibrio cholerae , mycobacterium tuberculosis, aspergillus niger and c. albicans were signifi cantly inhibited (mallikharjuna and seetharam 2009 ) . similarly, two benzophenanthridine alkaloids , dihydrochelerythrine and dihydrosanguinarinealkaloid constituents of bocconia arborea showed considerable antimicrobial activity against gram-positive and gram-negative bacteria and c. albicans ( navarro and delgado 1999 ) . sensitivity of dna and rna viruses to alkaloids may differ. ozçelik et al. ( 2011 ) investigated various alkaloids namely yohimbine and vincamine (indole -type), scopolamine and atropine (tropane-type), colchicine (tropolone-type), allantoin (imidazolidine-type), trigonelline (pyridine-type) as well as octopamine, synephrine, and capsaicin (exocyclic amine-type) for their antiviral activities against dna virus herpes simplex (hsv -1) type 1 and rna virus parainfl uenza type-3 (pi-3). all the alkaloids were effective against hsv -1 at 0.05-1.6 mg/l, but atropin and octopamine showed potent antiviral activities against pi-3 at 0.05-0.8 mg/l (ozçelik et al. 2011 ) . antibacterial alkaloids from chelidonium majus linn, i.e. benzo [c] phenanthridine -type alkaloids, 8-hydroxydihydrosanguinarine, 8-hydroxydihydrochelerythrine were potently active against mrsa strains with mics/mbcs ranged from 0.49 to 15.63 and 1.95 to 62.50 m g/ml, respectively (zuo et al. 2008 ) . there are two rich sources of organosulphur compounds from plants; (1) alliaceae family containing alliin -alliinase system and (2) cruciferae ( brassicacae ) family e.g. brassica juncea , wasabia japonica (wasabi), armoracia rusticana (horseradish) and brassica oleracea (caulifl ower) containing glucosinolate-myrosinase (mithen 2006 ) . a number of sulphur-containing compounds can be derived from these plants through the action of myrosinase and alliinase enzymes. the primary sulphur-containing constituents in alliums spp. (e.g. a. sativum (garlic), a. cepa (onion), a. porrum (leek)) and brassica spp. (e.g. cabbage, kale, caulifl ower and turnip) are s -alk(en)yl-l-cysteine sulphoxides and g -glutamyl-s -alk(en)yl-lcysteine sulphoxides (block et al. 1992 ; ross and milner 2007 ; fig. 1.3 ) . the content of s-alk(en)yl-l-cysteine sulphoxides in garlic may range from 0.53% to 1.3% of fresh weight with s -allyl-l-cysteine sulphoxide (alliin ) being the largest contributor. by the action of alliinase enzyme present inside the cells, these compounds are converted into thiosulfi nate (a functional group consisting of the linkage r-s(=o)-s-r'), which are then spontaneously and enzymatically converted into a large array of volatile compounds, e.g. diallyl disulphide, diallyl trisulphide, allyl methyl disulphide and dipropyl and disulphide (mithen 2006 ) . antimicrobial activities of garlic and onion against a wide range of grampositive and gram-negative bacteria, virus and fungi are known for many years (ankri and mirelman 1999 ) . the antifungal activities of garlic oils appear to be more than the antibacterial activity (avato et al. 2000 ) . extracts of garlic exhibit the most potent antibacterial activity, followed by onion, and brassica including cabbage (kyung and lee 2001 ) . the principal antimicrobial compounds of allium and brassica are allicin ( s -allyl-l-propene thiosulfi nate ) and methyl methanethiosulfinate, respectively (kyung and lee 2001 ) . these compounds are derived from s -allyl and s -methyl derivatives of l-cysteine sulfoxide , respectively. avato et al. ( 2000 ) tested different mixtures of garlic distilled oils containing diallyl disulfi de (dds) and diallyl trisulfi de (dts), ranging from 1% to 51% and 88% to 38%, respectively, against yeasts ( c. albicans, c. tropicalis and b. capitatus ), gram-positive bacteria ( s. aureus and b. subtilis ) and gram-negative bacteria ( p. aeruginosa and e. coli ). incubation of garlic extracts made up of 1% dds and 88% dts did not show growth inhibition against all the tested microorganisms, whereas garlic oils with higher quantities of dds showed signifi cant inhibitory activity, increasing with the increase of dds amount, thus implicating the dds as the active antimicrobial agent (avato et al. 2000 ) . it has been reported that allicin (mic, 6 m g/ml; mbc, 6 m g/ml) was more potent than dds (mic range, 100-200 m g/ml; mbc range, 100-200 m g/ml), its corresponding sulfi de, but of a strength similar to that of diallyl tetrasulfide (mic range, 3-6 m g/ml; mbc range, 3-6 m g/ml) against h. pylori (o'gara et al. 2000 ) . kyung and fleming ( 1997 ) investigated the different s-compounds found in cabbages on the growth of 15 bacteria and 4 fungi. s -methyl-l-cysteine sulfoxide, sinigrin , and dimethyl sulfi de at 500 ppm did not inhibit the growth of any of the bacteria and yeasts. dimethyl disulfi de at 500 ppm retarded the growth of some bacteria, but was not bactericidal to any of the test microorganisms. dimethyl trisulfi de , methyl methanethiosulfi nate and methyl methanethiosulfonate had mics of 200 ppm, between 50 and 200 ppm, and between 20 and 100 ppm, respectively for bacteria, and 20 ppm, between 6 and 10 ppm and between 50 and 500 ppm for yeasts, respectively (kyung and fleming 1997 ) . there are numerous reports showing the effectiveness of garlic or allicin as antimicrobial agents in comparison to antibiotics (fujisawa et al. 2009 ; cai et al. 2007 ) . also, allicin with antibiotics may synergistically augment the antimicrobial actions (cai et al. 2007 ; an et al. 2009 ) . besides, thiosulfi nates and their derivatives show promising activity against multidrug resistant bacteria including mrsa (ankri and mirelman 1999 ; fujisawa et al. 2009 ) . the main mode of action of thiosulfi nate derivatives have been proposed to be due to its chemical reaction with the thiol groups of various enzymes (ankri and mirelman 1999 ) and thus antimicrobial properties of allicin may be abolished by cysteine, coenzyme a and glutathione (fujisawa et al. 2009 ) . antimicrobial activity of the diallyl sulfi des has been reported to increase with the number of sulfur atoms (o'gara et al. 2000 ) . glucosinolates are the sulphur-containing metabolites found in large number of edible plants. over 120 glucosinolates are present in 16 families of dicotyledonous angiosperms, most of which are clustered within the brassicaceae and capparaceae (fahey et al. 2001 ) . allyl (sinigrin ) and 3-butenyl (gluconapin) glucosinolate are found in brown mustard, p -hydroxybenzyl glucosinolate in white mustard, allyl and other glucosinolate in horseradish and wasabi, methylthiopropyl in cabbage and 2-hydroxy 3-butenyl glucosinolate in rapeseed ( fig. 1.4 ; fahey et al. 2001 ; mithen 2006 ) . the antibacterial and antifungal properties of glucosinolates are known for a long time (fahey et al. 2001 ) . intact glucosinolates do not show antimicrobial action, but the hydrolysis products of glucosinolates are active against various microorganisms (manici et al. 1997 ; tierens et al. 2001 ) . aires et al. ( 2009a ) observed that the in vitro growth inhibition and the sensitivities of the individual bacteria are infl uenced by the structure of glucosinolates and their hydrolysis products. the most effective glucosinolate hydrolysis products were the isothiocyanates ; sulforaphane and benzyl isothiocyanate were the strongest inhibitory against the growth of human pathogenic bacteria. regarding action of glucosinolates products on the type of bacteria, 4-methyl sulfi nyl butylisothiocyanate exhibited antibacterial activity against a larger range of bacteria. indole-3-carbinol had some inhibitory effects against the gram-positive bacteria, but had no effect against the gram-negative bacteria. indole-3-acetonitrile had some inhibitory activity against the gram-negative bacteria. glucosinolates, nitriles and amines were ineffective at the doses up to 3 m mol (aires et al. 2009b ) . saavedra et al. ( 2010 ) evaluated the in vitro antibacterial actions of different classes of common dietary phytochemicals , i.e. simple phenolics -tyrosol, gallic acid, caffeic acid , ferulic acid , and chlorogenic acid ; chalcone -phloridzin; fl avan-3-ol -(−) epicatechin; secoiridoid -oleuropein glucoside; glucosinolate hydrolysis products -allyl isothiocyanate, benzyl isothiocyanate and 2-phenylethyl isothiocyanate) against four pathogenic microbes. all of the isothiocyanates had signifi cant antimicrobial activities, while the phenolics were much less effi cient. no antimicrobial activity was observed with phloridzin. allyl isothiocyanate from cabbage had an mic between 50 and 500 ppm for bacteria and between 1 and 4 ppm for yeasts (kyung and fleming 1997 ) . iridoids is a group of cyclic monoterpenoids having iridane skeleton (cis-2-oxabicycle-(4.3.0)-nonane), which mostly remain as glycosides ( fig. 1.5 ; perez et al. 2005 ) . secoiridoids derive from iridoids by the elimination of the link 7-8 to yield the basic structure (perez et al. 2005 ) . this group of phytochemicals is found in a number of folk medicinal plants and many of them possess signifi cant biological and pharmacological activities (dinda et al. 2009 ) . a number of iridoids and secoiridoids (nepetalactones from serbian nepeta species , nestorović three iridoids, phloyoside1, phlomiol, and pulchelloside 1, isolated from the rhizomes of the iranian fl ora eremostachys laciniata ( lamiaceae ) had low to moderate levels of antibacterial activity (mic = 0.05-0.50 mg/ml) against fi ve bacterial strains, bacillus cereus , citrobactor freundii , proteus mirabilis , p. aeruginosa , s. aureus (modaressi et al. 2009 ) . out of these three compounds, pulchelloside 1 showed highest antibacterial activity against b. cereus , penicillin-resistant e. coli , p. mirabilis and s. aureus with an mic value of 0.05 mg/ml. nestorović et al. ( 2010 ) investigated the nepetalactones content in the methanol extracts of the shoot cultures of three endemic serbian nepeta species: nepeta rtanjensis , n. sibirica and n. nervosa , and evaluated the antimicrobial activity of these extracts against eight bacterial strains e. coli , p. aeruginosa , s. typhimurium , listeria monocytogenes , enterobacter cloacae (human isolate), b. cereus (clinical isolate), micrococcus fl avus and s. aureus , and eight fungal species: aspargillus fl avus , aspargillus fumigatus , aspargillus niger , fusarium sporotrichoides , fulvia fulvum, penicillium funiculosum, p. ochrochloron and trichoderma viride . trans, cisnepetalactone was present in shoots of n. rtanjensis , while cis,trans -nepetalactone stereoisomer was present in n. sibirica . no nepetalactone was observed in shoots of n. nervosa . all these extracts had signifi cant antibacterial and antifungal activities against all the tested species. n. rtanjensis extract showed the strongest antibacterial activity with mic of 50 m g/ml. n. nervosa and n. sibirica extracts showed antibacterial activities with mic of 50-100 and 100 m g/ml, respectively. similarly, n. rtanjensis, n. nervosa and n. sibirica extracts showed mic of 25-5, 50-100 and 25-100 m g/ml, respectively. the presence of trans-nepetalactone in n. rtanjensis extract was probably responsible for strongest activity against bacteria and fungi, while cis-nepetalactone in n. sibirica extract showed higher antibacterial and antifungal activity than that of n. nervosa extract. (geng et al. 2009a (geng et al. , b, 2011 . iridoid aglycone moieties, but not its glycosides , exhibit the antiviral activities. zhang et al. ( 2009 ) studied an anti-hepatitis c virus pseudoparticles (hcvpp) entry essay on both aqueous and methanol extracts of the fl owering tops of lamium album . iridoid glucoside lamalbid isolated from the methanol extract was inactive against hcvpp, whereas its aglycone, and epimers named lamiridosins a and b present as major constituents in the aqueous extract signifi cantly inhibited in vitro hcv entry (ic50 value of 2.31 m m). these were nontoxic to the hep g2 2.2 cells at a concentration of 50 m g/ml. they also demonstrated that the parent iridoid glycosides did not show anti-hcv entry activity, but the aglycones of shanzhiside methyl ester, loganin, loganic acid, verbenalin, eurostoside and picroside ii exhibited signifi cant anti-hcv entry and anti-infectivity activities. chemically, saponins are a group of high molecular-weight glycosides , in which saccharide chain units (1-8 residues) are linked to a triterpene (triterpene saponins ) or steroidal (steroid saponins) aglycone moiety, i.e. sapogenin (fig. 1.6 ) . they occur in a wide variety of plants with triterpene saponins (in soybean, alfalfa, quillaja, and guar), and are more widely distributed in nature than steroidal (in yucca, tomato, and oats) saponins ( hostettmann and marston 1995 ) . the steroidal saponins may possess furostanol or spirostanol (e.g. smilagenin and sarsapogenin) moiety. the saccharide chains are commonly attached at the c3 position (monodesmosidic), but some sapogenins contain two saccharide chains (bidesmosidic) attached at the c3 and c17 (via c28) position (vincken et al. 2007 ) . a large number of saponins could be possible depending upon the modifi cations of the ring structure of aglycone moieties and number of sugars added to it, and in turn producing different biological properties. many plant extracts containing saponins from various plants and purifi ed saponins show antimicrobial activities at different concentrations (sen et al. 1998 ; avato et al. 2006 ) . however, the types of saponins exhibit different spectra of antimicrobial effects. oleanolic acid isolated from the root bark of newbouldia laevis have broad-spectrum antimicrobial activity against 6 gram-positive, 12 gramnegative bacterial species and three candida species (kuete et al. 2007 ) . b -sitosterol-3-o -b -d-glucopyranoside isolated from this plant also showed antibacterial effects on three gram-positive, six gram-negative bacterial species and three candida species. a saponin fraction from the stem of y. schidigera exhibited potent growthinhibitory activity with mic ranging from 31.3 to 125 m g/ml against certain food-deteriorating yeasts ( c. albicans ), fi lm-forming yeasts ( debaryomyces hansenii, pichia nakazawae, zygosaccharomyces rouxii ), dermatophytic yeasts ( candida famata, hansenula anomala, pichia carsonii ), and against brewer's yeast ( saccharomyces cerevisiae ) (miyakoshi et al. 2000 ) . different saponins, i.e. tigogenin from tribulus terrestris , dioscin from the rhizomes of smilacina atropurpurea , minutosides from bulb of allium leucanthum were very active against different fungal strains such as c. albicans , c. glabrata and cryptococcus neoformans (zhang et al. 2006a, b ; barile et al. 2007 ) . saponins appear to have stronger activities against fungi, and act by disrupting the membrane integrity of fungal cells. different extraction procedures and storage may affect the antimicrobial action of saponins probably due to chemical transformation of saponins (guclu-ustundag and mazza 2007 ) . commercially produced quillaja ( quillaja saponaria ) and yucca ( yucca schidigera ) saponins showed different antibacterial activities against e. coli , suggesting that saponins from various commercial sources differ in their biological activities (sen et al. 1998 ) . in this study, commercial saponin-rich quillaja and yucca extracts exhibited antibacterial activity against s. aureus and e. coli at different concentrations. the antimicrobial activity of saponins may also be modifi ed by the ph of media. the tea saponins exhibited greater antimicrobial activities against gram-positive s. aureus (mic <0.006 vs. >0.2), gram-negative e. coli (mic 0.003 vs. >0.2) and c. albicans (mic <0.006 vs. >0.2) at low ph 4 than high ph 8.5 (li et al. 2009 ) . some saponins , in general, exhibit stronger antimicrobial activity against gram-positive bacteria than against gram-negative bacteria (avato et al. 2006 ) . saponins fraction from soapnut pericarps ( sapindus mukurossi , tanaka et al. ( 1996 ) and guar ( cyamopsis tetragonoloba , hassan et al. 2010a, b ) showed greater antibacterial activity against gram-positive bacteria than against gram-negative bacteria. conversely, saponins isolated from orchid tree ( bauhinia variegata l.) bark exhibited greater antibacterial activity for gram-negative bacteria than gram-positive bacteria at concentrations ranging from 2.5 to 10 mg/ml (morrissey and osbourn 1999 ) . the relationships between saponin structures and antimicrobial activity are strongly noted. the structure of sapogenin moiety, chain length and composition of sugars infl uences the antimicrobial activities. the y. schidigera saponin fraction possessing a trisaccharide chain without any oxygen functionalities at c-2 and/or c-12 of the aglycone exhibited potent anti-yeast activity, while saponins with 2b-oh or 12-keto groups showed very weak or no activity. low activity was observed for saponins with a disaccharide chain and no activity was observed for the aglycones obtained after acid hydrolysis (miyakoshi et al. 2000 ) . yang et al. ( 2006a ) noted that no activity was observed in the hecogenin saponins when its sugar moiety was less than four monosaccharide units. pentaglycoside was more active than tetraglycoside and shows extended antifungal spectrum against a. fumigatus . in the diosgenin saponin series, saponins with only triglycosides are active against c. albicans and c. glabrata , while the diosgenin saponins with monoglycoside and diglycoside did not show any activity. again, within the group of tigogenin saponins, their antifungal capacity was slightly infl uenced by the composition of the sugar moiety. the replacement of a glucosyl unit with a xylosyl unit showed enhanced activity against a. fumigatus . avato et al. ( 2006 ) suggested that the sugar moiety is not important for the antimicrobial effi cacy from their study since antibacterial activity increased from the saponin extracts to the sapogenin samples. terpenoid compounds derive from a basic structure of c5 isoprene units. they are classifi ed according to the number of isoprene unit involved for their synthesis, i.e. monoterpenoid (c10), sesquiterpenoids (c15), diterpenoids (c20), sesterterpenoids (c25) and triterpenoids (c30). they can be acyclic (myrcene and geraniol), monocyclic (cymene and carvacrol), bicyclic (pinene) and tricyclic with different groups (alcohol, phenol, and aldehyde). the most commonly occurring essential oils (eo) are included in two chemical groups (fig. 1.7 ) : terpenoids (monoterpenoids and sesquiterpenoids) and phenylpropanoids, which are synthesized through mevalonate and shikimic acid metabolic pathways, respectively (gershenzon and croteau 1991 ; calsamiglia et al. 2007 ) . among these two classes, terpenoids are the more diversifi ed group of plant bioactives abundantly found in many herbs and spices (gershenzon and croteau 1991 ) . within terpenoids, the most important components of eo of the majority of plants belong to the monoterpenoids and sesquiterpenoids (gershenzon and croteau 1991 ; calsamiglia et al. 2007 ) . phenylpropanoids have a side chain of three carbons bound to an aromatic ring of c6 (calsamiglia et al. 2007 ) . phenylpropanoids are less abundant compounds of eo compared with terpenoid family, but some plants contain in signifi cant proportions. the eo are a group of secondary plant metabolites obtained from volatile fractions of plants by steam distillation process (gershenzon and croteau 1991 ) . the eo are used traditionally by humans, for many centuries, which provide characteristic fl avor and aroma specifi c to many plants, and are used as antimicrobial agents and preservatives. the eo have diverse chemical composition, nature and biological properties. the eo can be obtained from fl owers, petals, leaves, stems, fruits, roots and barks and the concentrations of eo in these parts depends upon the stage of growth, environmental conditions (hart et al. 2008 ) . a number of eo are known for their strong anti-microbial activities against many pathogenic and non-pathogenic bacteria and fungi. curcumin and its derivatives, the phenylpropanoids, are the principal compounds in rhizome of curcuma longa (turmeric), which exhibit antibacterial properties against different bacteria and fungi. essential oil fractions of turmeric inhibited the growth of pathogenic gram-positive ( s. aureus and staphylococcus epidermidis ) and gram-negative ( e. coli , p. aeruginosa and s. typhimurium ) bacteria (singh et al. 2002 ) . the eo fraction was more effective against gram-positive compared to gram-negative strains, and was comparable to standard antibiotics gentamycin, ampicillin, doxycycline and erythromycin in these strains (singh et al. 2002 ) . a recent study by de et al. ( 2009 ) demonstrated that curcumin inhibited the growth of different clinical isolates of h. pylori with mics ranging from 5 to 50 m g/ml. the gingerols, another phynylpropanoids from zingiber offi cinalis (zinger), possess antifungal and antibacterial properties (park et al. 2008 ) . ginger extract containing gingerol inhibited the growth of h. pylori with mics ranging from 0.8 to 12.5 m g/ml (mahady et al. 2003 ) . constituents of eo differ in their antimicrobial activity against bacteria and fungi. investigating the antimicrobial properties (18 bacterial species and 12 fungi) of fi ve eo constituents (cineole, citral, geraniol, linalool and menthol), pattnaik et al. ( 1997 ) showed that linalool had the most antibacterial activity and inhibited 17 bacteria, followed by cineole, geraniol (each of which inhibited 16 bacteria), menthol and citral aromatic compounds, which inhibited 15 and 14 bacteria, respectively. however, the antifungal activities of these eo constituents did not follow the pattern of antibacterial activities. citral and geraniol oils were the most effective against fungi (inhibiting all 12 fungi), followed by linalool (inhibiting 10 fungi), cineole and menthol (each of which inhibited 7 fungi) compounds (pattnaik et al. 1997 ) . it has been suggested that the ph of eo in culture media may modify antimicrobial properties. for example, anise oil had higher antifungal activity at ph 4.8 than at 6.8, while the oil of cedrus deudorawas was most active at ph 9 (janssen et al. 1987 ) . the structure and stereochemistry of the essential oils have profound infl uences on the antimicrobial activities. alkenyl substituents incorporated into nonphenolic ring structures of essential oils such limonene showed increased antibacterial activities compared with alkyl substituents such as p -cymene with alkylation showing more inhibitory effect on gram-negative bacteria (dorman and deans 2000 ) . from stereochemistry of eo, it has been reported that a -isomers such as a -pinene are less active relative to b -isomers such as geraniol and nerol; cis -isomers are inactive contrary to trans -isomers; compounds with methyl-isopropyl cyclohexane rings are the most active; or unsaturation of the cyclohexane ring further increases the antibacterial activity, e.g. terpinolene, terpineol and terpineolene (hinou et al. 1989 ; dorman and deans 2000 ) . however, griffi n et al. ( 1999 ) reported that the specifi city and level of antimicrobial activity of terpenoids were not always characterized by the functional groups, but were associated with hydrogen-bonding parameters, and for gram-negative organisms a combination of hydrogen-bonding parameters and molecular size parameters. the antimicrobial properties of eo from different sources have been discussed in details elsewhere (chap. 5 ). chemically, limonoids are unique secondary metabolites, characterized by a tetranortriterpenoid skeleton with a furan ring ( fig. 1.8 ) . they are commonly isolated from citrous and maliaceae plants (hallur et al. 2002 ; rahman et al. 2009 ; vikram et al. 2010 ) . besides their health promoting effects, various limonoids have been shown to possess antibacterial, antifungal and antiviral effects (govindachari et al. 2000 ; battinelli et al. 2003 ; atawodi and atawodi 2009 ) . various limonoid compounds such as mahmoodin , azadirone , epoxyazadiradione, nimbin , gedunin, azadiradione , deacetylnimbin and 17-hydroxyazadiradione, isolated from various parts of azadirachta indica (meliaceae family) have been reported to have antimicrobial activities (siddiqui et al. 1992 ; govindachari et al. 2000 ; atawodi and atawodi 2009 ) . rahman et al. ( 2009 ) tested two limonoids isolated from the seeds of swietenia mahagoni ( meliaceae family), swietenolide and 2-hydroxy-3-o-tigloylswietenolide against various multiple-drug-resistant bacterial strains including gram-positive ( s. aureus , s. pneumoniae and haemophilus influenzae ) and gram-negative ( e. coli , klebsiella pneumoniae, salmonella typhi, and salmonella paratyphi ) strains. the most potent activity of swietenolide was observed against h. infl uenzae , s. typhi , and s. paratyphi , whereas 2-hydroxy-3-o-tigloylswietenolide was most active against s. pneumoniae, s. typhi, and s. paratyphi . the lowest activity was observed against k. pneumoniae for both compounds. the limonoids compounds may exhibit antibacterial properties against pathogenic bacteria by disrupting the quorum sensing system and biofi lm production. vikram et al. ( 2010 ) demonstrated limonin, nomilin, obacunone, deacetyl nomilin and limonin 17-o-b -d-glucopyranoside purifi ed from seeds of grapefruits to possess the anti-quorum sensing activity and inhibitory effect on biofi lm formation of pathogenic e. coli o157:h7 with obacunone exhibiting strong antagonistic activity. limonoids also have signifi cant antiviral activity. limonin and nomilin showed inhibitory effects on hiv -1 replication in peripheral blood mononuclear cells and monocytes/macrophages, which was not cytotoxic at the active concentrations (battinelli et al. 2003 ) . the antiviral activity was not much infl uenced by structural differences by limonin and nomilin in this study (battinelli et al. 2003 parida et al. ( 2002 ) demonstrated in an in vivo study that azadirachtin obtained from a. indica inhibited dengue virus type-2 replication as confi rmed by the absence of dengue-related clinical symptoms in sucking mice and absence of virus specifi c 511 bp amplicon. more than 700 polyacetylene compounds have been characterized from plants, which are mainly prominent in the asteraceae, apiaceae and campanulaceae including many medicinal plants from various parts of the world (hudson 1989 ) . food plants of the apiaceae plant family such as carrots, celery, parsley, fennel and parsnip contain a group of bioactive aliphatic c17-polyacetylenes including falcarinol, falcarindiol, panaxydiol, and polyacetylene 8-o-methylfalcarindiol (zidorn et al. 2005 ; christensen and brandt 2006 ) . avato et al. ( 1997 ) investigated the different polyacetylene compounds from the aerial organs of bellis perennis l. of the major constituents, methyl deca-4,6-diynoate and deca-4,6-diynoic acid, and their structural analogues, i.e. deca-4,6-diyne, dimethyl octa-3,5-diyne-1,8-dioate and deca-4,6-diyne-1,10-dioic acid, deca-4,6-diynoic acid and deca-4,6-diyne-1,10-dioic acid showed antimicrobial activity against gram-positive and gram-negative bacteria, respectively. polyacetylene carboxylic acids, 13( e ),17-octadecadiene-9,11-diynoic acid (13,14-dihydrooropheic acid, and the known 17-octadecene-9,11,13-triynoic acid (oropheic acid, isolated from the stem bark of mitrephora celebica demonstrated signifi cant activity against mrsa and mycobacterium smegmatis (zgoda et al. 2001 ) . similarly, pentayne diol, a polyacetylene which was isolated from bidens pilosa (a traditional medicinal herbs) showed highly potent and extensive inhibitory activities against several gram-positive and gram-negative pathogenic bacterial species, including mrsa , and vancomycin-resistant enterococcus faecalis and c. albicans (tobinaga et al. 2009 ) . in a recent fi nding, a polyacetylene compound from carlina acaulis , i.e. carlina oxide exhibited strong antibacterial activity against two mrsa strains, streptococcus pyogenes, p. aeruginosa, c. albicans , and c. glabrata with less toxicity to human hela cells (herrmann et al. 2011 ) . anthranoid compounds are widely distributed in various plants particularly in aloe , cassia, rheum , cassia and frangula , which are traditionally used in ethnomedicine for laxative and cathartic action (paneitz and westendorf 1999 ) . naturally occurring anthranoids can be chemically described as dihydroxyanthraquinones, -dianthrones and -anthrones, often present in plants as glycones (table 1. 2 ; paneitz and westendorf 1999 ) . different anthranoids such as aloe-emodin, rhein, emodin, physcion and chrysophanol occur in rheum species. anthranoids have shown antimicrobial properties in different studies. the anthranoid compounds from the rhizome of rheum emodi exhibited antibacterial and antifungal activities (babu et al. 2003 ) . the antimicrobial effects of the three anthraquinones on s . aureus found to be in the order of rhein > emodin > 1,8-dihydroxyanthraquinone (wu et al. 2006 ) . similarly, wang et al. ( 2010 ) demonstrated that the sequence of antimicrobial activity against bifi dobacterium adolescentis of the fi ve hydroxyanthraquinones was rhein > emodin > aloe-emodin > chrysophanol > physician. they also suggested the infl uence of substituent groups on phenyl ring in hydroxyanthraquinones against b. adolescentis activity might be related with the polarity and the sequence was carboxyl > hydroxyl > hydroxylmethyl > methyl and methoxyl. prenylated anthranoids from leaves of harungana madagascariensis have shown to inhibit bacillus megaterum (kouam et al. 2007 ) . additionally, the effect of emodin with antibiotics (ampicillin and oxacillin) was found to be synergistic or partially synergistic against mrsa, where emodin reduced the mics of the antibiotics (lee et al. 2010 ) . however, some of the anthranoids have potent mutagenic effect (paneitz and westendorf 1999 ) , which is required to consider when evaluating the antimicrobial properties of these compounds. there is considerable evidence that a number of phytochemicals have potential to become useful antimicrobial agents that could be employed as preventative or treatment therapies against microbial and viral diseases. although, there are some encouraging effects in vivo to inhibit pathogenic microbes without affecting benefi cial bacteria in the gastrointestinal tracts, more studies would be required for the safety and effi cacy of these phytochemicals to establish whether they could offer therapeutic benefi ts over conventional therapies. besides, the combination of some antimicrobial drugs and phytochemicals may act as better antimicrobial agents than antimicrobial drugs alone. for example, the application of dual combinations demonstrated synergy between streptomycin and gallic acid, ferulic acid , chlorogenic acid , allylisothiocyanate and 2-phenyle thylisothiocyanate against the gram-negative bacteria. moreover, they can act synergistically with less effi cient antibiotics to control bacterial growth (saavedra et al. 2010 ) . 3,4-dihydroxyphenylacetic acid and 3-hydroxyphenylacetic acid increased the susceptibility of s . enterica subsp. enterica serovar typhimurium strains for novobiocin. in addition, organic acids present in berries, such as malic acid, sorbic acid, and benzoic acid , were shown to be effi cient permeabilizers of salmonella as shown by an increase in the 1-n-phenylnaphthylamine uptake assay and by lipopolrsaccharide release (alakomi et al. 2007 ) . cinnamon essential oil and its major component (trans-cinnamaldehyde) enhanced the antibacterial activity of clindamycin against a toxicogenic strain of clostridium diffi cile ) . in addition, the enhancement activity of different essential oils ( mentha longifolia l. and mentha spicata l.) and different monoterpenes (piperitone, carvone and menthone) on the antibacterial activity of nitrofurantoin has been reported (rafi i and shahverdi 2007 ; shahverdi et al. 2004 ) . the antibacterial activity of cefi xime, cephotaxime, vancomycin and tetracycline was also increased by curcumin (moghaddam et al. 2009 ) . allicin has a synergistic effect with amphotericin b against c. albicans via enhancing the phospholipid peroxidation reaction in vitro and in vivo , which suggests that allicin could reduce the amphotericin b dose to lessen side effects ) . due to the growing use of phytochemicals and other dietary phytochemical-rich supplements, it is required to understand whether problems might arise from using these preparations in combination with conventional drugs. there is lack of comprehensive studies that can establish the consequences of phytochemicals-drug interactions. however, all these evidence also suggest that intake of phytochemicals rich foods could be considered in future research while antimicrobial agents are applied to the body. plant genomes contain 20,000-60,000 genes, and about 15-25% of these genes encode enzymes for secondary metabolism (bevan et al. 1998 ; somerville and somerville 1999 ) . the genome of a plant species encodes only a small fraction of all the enzymes that are required to synthesize the entire set of secondary metabolites found throughout the plant kingdom (pichersky and gang 2000 ) . identifi cation of particular genes for target phytochemicals and the genetic engineering techniques could allow expressing the biosynthetic pathways of some phytochemical synthesis in organisms such as e. coli , b. subtilis or s. cerevisiae . for example, miyahisa et al. ( 2006 ) reported that introduction of four genes for a phenylalanine ammonia-lyase, cinnamate/coumarate:coa ligase, chalcone synthase, and chalcone isomerase, in addition to the acetyl-coa carboxylase, in e. coli cells resulted in effi cient production of (2s)-naringenin from tyrosine and (2s)-pinocembrin from phenylalanine. finally, the possibility of using phytochemicals as antimicrobial compounds would be a paradigm shift towards the potential health benefi ts and safety overcoming the problem of microbial resistance to drugs. antibacterial activity of diospyrin, isodiospyrin and bisisodiospyrin from the root of diospyros piscatoria (gurke) (ebenaceae) initial in vitro evaluations of the antibacterial activities of glucosinolate enzymatic hydrolysis products against plant pathogenic bacteria the antimicrobial effects of glucosinolates and their respective enzymatic hydrolysis products on bacteria isolated from the human intestinal tract weakening of salmonella with selected 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toxicity of anthraquinones by microcalorimetric bioassay anti-aids agents. 37. synthesis and structureactivity relationships of (3 ¢ r,4 ¢ r)-(+)-cis-khellactone derivatives as novel potent anti-hiv agents antifungal activity of c-27 steroidal saponins five new iridoids from patrinia rupestris different susceptibilities of staphylococcus and gram-negative rods to epigallocatechin gallate polyacetylene carboxylic acids from mitrephora celebica antifungal activities and action mechanisms of compounds from tribulus terrestris l atropurosides a-g, new steroidal saponins from smilacina atropurpurea lamiridosins, hepatitis c virus entry inhibitors from lamium album polyacetylenes from the apiaceae vegetables carrot, celery, fennel, parsley, and parsnip and their cytotoxic activities antibacterial alkaloids from chelidonium majus linn (papaveraceae) against clinical isolates of methicillin-resistant staphylococcus aureus key: cord-102632-yazl9usb authors: lobet, guillaume; descamps, charlotte; leveau, lola; guillet, alain; rees, jean-françois title: quovidi: a open-source web application for the organisation of large scale biological treasure hunts date: 2020-07-01 journal: biorxiv doi: 10.1101/2020.06.30.177006 sha: doc_id: 102632 cord_uid: yazl9usb learning biology, and in particular systematics, requires learning a substantial amount of specific vocabulary, both for botanical and zoological studies. while crucial, the precise identification of structures serving as evolutionary traits and systematic criteria is not per se a highly motivating task for students. teaching this in a traditional teaching setting is quite challenging especially with a large crowd of students to be kept engaged. this is even more difficult if, as during the covid-19 crisis, students are not allowed to access laboratories for hands-on observation on fresh specimens and sometimes restricted to short-range movements outside their home. here we present quovidi, a new open-source web platform for the organisation of large scale treasure hunts. the platform works as follows: students, organised in teams, receive a list of quests that contain morphologic, ecologic or systematic terms. they have to first understand the meaning of the quests, then go and find them in the environment. once they find the organism corresponding to a quest, they upload a geotagged picture of their finding and submit this on the platform. the correctness of each submission is evaluated by the staff. during the covid-19 lockdown, previously validated pictures were also submitted for evaluation to students that were locked in low-biodiversity areas. from a research perspective, the system enables the creation of large image databases by the students, similar to citizen-science projects. beside the enhanced motivation of students to learn the vocabulary and perform observations on self-found specimens, this system allows faculties to remotely follow and assess the work performed by large numbers of students. the interface is freely available, open-source and customizable. it can be used in other disciplines with adapted quests and we expect it to be of interest in many classroom settings. teaching biology to first-year bachelor students is a challenge. as educators, our aim is usually twofold. first, we want the students to learn a new set of knowledge and integrate it. second, and this is for us equally important, we want the students to engage with the topic at hand. we want to transmit our passion and curiosity about the topic that we teach. third, we also want students to learn to observe the world around them. it is one thing to learn a topic from a textbook, it is another to observe it in real life. however, the main issue is that the classroom is, often by design, completely disconnected from the natural world. the challenge is therefore to find a way for students to learn and engage with biology, despite that given disconnection. last but not least, in the spring semester of 2020 (january to june) it was necessary for us to adapt the learning activities to the containment measures related to covid-19. the formal aim of our biology course -given in the bioengineering faculty, uclouvain, belgium -is to discover plant and animal structures, organs and their function at the individual scale. to achieve this, students need to learn specific vocabulary related to these structures. the classic way to present this vocabulary to a student audience is to review a series of slides illustrating these different characteristics. this vocabulary is usually very boring for teachers to describe (imagine the slides showing all the different shapes of leaves) and the content is not very interesting for students to listen to either. yet this vocabulary is an important prerequisite for describing any biological structure and for later systematic identification of taxons using dichotomous keys . its learning is essential. the question is therefore how to make this learning process motivating for the students and give them the opportunity to learn over time instead of memorising a list of words? the additional difficulty is that this learning activity must be able to be set up with more than 300 students and few teaching resources. to create this learning activity, we decided to draw inspiration from all the pedagogical techniques that aim to place the student at the centre of his learning. student-centred learning and active learning emerged as important pedagogical techniques during the last century [ref] . active learning is characterised by (i) involving the student in the construction of his or her learning, (ii) engaging the student in an in-depth treatment of the subject matter, (iii) constructing learning through interaction (with the teacher or other students), (iv) conceiving of learning as the evolution of knowledge and skills [1, 2] . studies have shown that the more cognitively and socially engaged the student is in a learning task, the more perennial the learning task becomes [1, 3] . active learning improves the performance of students and acts to reduce the gap achievement between advantaged and disadvantaged students [4] . in order to stimulate learning through interaction and create a collective emulation around this activity, the idea of creating a campus-wide biological treasure hunt finally emerged from the discussions. beyond simply being active through the manipulation of information, the student has to transform and produce new information that is not provided in the learning material. gamification is another recent technique to better engage the students in a learning activity. gamification is defined by [5] as "game-based mechanics, aesthetics, and game thinking to engage people, motivate action, promote learning, and solve problems". in many studies, students' levels of engagement increased significantly following the introduction of game elements, such as points, challenges, quests or progress bar [6] . the gamified environnement can afford intrinsic motivation and engagement, which are also targeted by active learning. to assemble these different elements -biological vocabulary, observation, active learning and gamification -in a comprehensive learning activity, we created a large scale biological treasure hunt for our students. in short, we provided students with a list of specific biological vocabulary. they had to understand the list and find the different elements outside of the classroom, in the natural world. external resources (books, selected websites, wiki pages) describing this vocabulary were available to them. complexity of understanding (some words are more difficult than others) as well as the difficulty of identification in the field were rewarded with different points. to manage the treasure hunt, we designed a new web-based platform, quovidi (which would loosely translate from latin as "where did you see"), for the organisation of large scale, decentralised, biological treasure hunts. quovidi is an open-source project available at www.quovidi.xyz . the objective of this publication is to describe the project, to show how we were able to adapt this learning activity to the covid-19 crisis, and finally, to show the results and success of the activity with the students. quovidi is a web application for the organisation and management of large scale biological treasure hunts. it was created to teach students to learn new biological terms (both in zoology and botany) and to teach them to observe the natural world surrounding them. first, educators have to prepare a list of quests to find in the natural world. these quests should be tailored and adapted for the target public. for instance, in our experience with first year biology students, the quests revolved around biological structures and families (tab. 1). each quest is given a specific reward (points) depending on its intrinsic difficulty and rareness. quests can be sorted in different groups (for instance "animal" and "plant") and subgroups (for instance "animal species" and "leaf shapes") to help students navigate them. find a siphonaptera animal animal groups 3 find an example of aposematism animal animal physical attributes 1 second, educators have to assign students to groups to perform the activity. students in the same group will be able to share pictures and collaborate on the data collection. when logging into the web interface, students will be able to see the collected pictures and rewards from their own group. they will also be able to see the total number of points of the competing groups. educators also have the possibility to define specific game parameters, such as specific geographic regions in which the game takes place or restriction on the number of submissions in each quest group (adding for instance a point penalty below a certain number of "animal" or "plant" submissions). once the list of quests, users and groups are defined, the activity can start. two main activities are available for the students : an in situ treasure hunt and an ex situ photo quiz activity. the main activity of the platform is the biological treasure hunt. students have to go outside (although some of the creatures may be also found in their home such as food parasites, e.g. lepisma sp. or flies) to find the different quests setup by the educators. once they find a specific quest, they have to take a picture of it with their smartphone. we ask the student to take unambiguous pictures, where the subject of the quest is clearly identified and visible. we also ask them to leave the natural environment intact, without killing any plant or animal in the process. they can then store the picture on the quovidi web interface. when stored, pictures are automatically resized (for efficiency) and added to the activity database. localisation information and date are extracted from the picture exif metadata. any other information is erased at this step. once pictures are stored on the web interface, students can assign them to a specific quest and submit it for evaluation. the web application allows users to follow their progress in detail (which picture was submitted for which quest, what is the evaluation status, etc.) as well as the global progress of the other groups (the total number of collected points). it is worth noting that in belgium -where the web application was first usedthe lockdown due to the covid-19 pandemic still allowed citizens to go outside for some walk and exercise, although at a limited range. as such, the treasure hunt could still be performed by the students, either in their own garden or in neighbouring areas. however, not everyone lives in the countryside or close to a natural environment, or had the opportunity to leave their home during the lockdown. this is why we created a second module in the interface, the photo quiz, which allowed students to learn from photos contributed by other students, without having to submit their own photos. the second module of the interface allows students to evaluate pictures submitted by other students (a modified version of peer evaluation). more precisely, in the photo quiz module, students are presented with pictures submitted by other groups and validated by the educators (see below "expert evaluation). they have to assess whether the picture corresponds to its assigned quests. their assessment is then compared to the assessment of the educators. if it matches, the students gain points that are added to their global group tally. when performing this activity for the first time, it is necessary to have a sufficient amount of submitted (and corrected pictures). without a database large enough, the activity loses some of its interest, as students might all review the same pictures. the third important module of the interface, central to the activity, is the expert evaluation. each submitted picture needs to be manually assessed by the educators. different feedback can be given for each submission, such as "correct", "correct and nice picture", "incorrect" , "not visible" (e.g. the object is not visible in the picture) or "out of rules" (e.g. picture of a houseplant, picture taken outside of the prescribed geographical zones). the interface was designed to easily navigate the different quests and quickly correct the submitted images. the web application was created using the r shiny framework , using the shinydashboard [7] , shiny [8] , shinywidgets [9] , shinybs [10] , miniui [11] packages for the user interface design. the data is stored in a sqlite database, hosted on the server. the database management is done using the dbi [12] and rsqlite [13] packages . pictures are transformed and managed using the magick [14] package. exif information is extracted using the exifr [15] package. data manipulation and visualisation is done using the tidyverse [16] , lubridate [17] , cowplot [18] , formattable [19] , dt [20] , plyr [21] , leaflet [22] packages. the text sentiment analysis was performed using the rfeel package [23] . in our exemple, the web application was deployed on the university server with the following specifications: quovidi is an open source project, released under an apache licence [24] . everyone is free to re-use and modify it, with attribution. the interface was created to be as much user-friendly as possible so that neither students nor staff need technical training . because it is web based, it can be used on any platform, whatever the operating system . it scales on mobile devices as well, allowing users to store and submit pictures directly from the field (if they have an internet connection). figure 1 shows the different panels of the web interface. figure 1a shows the "store" panel, where students can store pictures, before submitting them for evaluation. this allows students from the same group to share and visualise their pictures. at this step, students can already assign a quest to the picture, which can be changed later on. they can also assign a geographic region, if this is required by the educators. a default region will be automatically proposed, based on the metadata of the picture. figure 1b shows the "submit" panel. at this stage, students see all the pictures from their group. they can select a stored picture, assign it to a quest and submit it for evaluation. groups can only submit one picture for each quest. or not as well as their validation status. in the same panel, students can also see the global scores of each group taking part in the activity. this adds a strong gamification aspect to the activity. figure 1d shows the "quests" panel. in that panel students can navigate through the different quests proposed by the educators. they can sort them by groups, subgroups or rewards. in this panel, no explanation is given for the different quests. for instance if the quest is "find an achene", we do not define achene. this is done by design. we want students to look up the different biological terms by themselves. we do provide them with ressources to do so. when an educator logs into the web application, the "quests'' panel becomes the "admin" panel. in this panel, educators can follow the evolution of the activity ( fig. 2a) , change the activity parameters ( fig. 2b ) or correct the student submissions ( fig 2c) . depending on the number of participating students and allowed submissions, the number of corrections can quickly become quite large. therefore we designed the corrections interface to be fast and efficient. the educator first chooses one quest to correct. he·she will in spring 2020, we organised the activity with a rooster of 346 first year bachelor students from the bioengineering faculty of the uclouvain (belgium). students were spread in 346 groups (it was therefore set up as an individual activity). although students had to do the activity individually, we encouraged them to discuss the different quests and collect them together, as long as everyone took their own pictures. each group was allowed to submit a maximum of 50 pictures. 285 quests were created, divided in 175 plant quests and 110 animal quests. specific restrictions were added to the game. a minimal number of animal and plant quests had to be collected by each group. groups were also asked to the activity started on february 11. we had to pause the activity for 20 days at the beginning of the lockdown due to the covid19 crisis. during that pause, we implemented the peer-evaluation in the web interface (it was not part of the interface initially). the activity resumed on the 3d of april and finished on the 15th of may. for the second phase of the activity, during the lockdown, all restrictions (quests groups and zones) were lifted as many students had returned to their home far away from the campus. at the end of the activity, we sent an anonymous feedback form to the students and received 125 answers. a total of 6543 pictures were submitted by students during the 2020 activity. figure 3 shows the repartition of the submitted pictures by the students during the activity. figure 3a & b show the difference before and after the lockdown imposed during the covid-19 crisis. before the lockdown, as we asked students to take pictures around the university, most of them were taken in louvain-la-neuve. during the lockdown, almost no pictures were taken in louvain-la-neuve, as students went back home. the lockdown reduced the number of collected pictures, but did not stop it. this is due to several reasons. at the beginning of the activity, we encouraged students to look for quests in groups, to foster peer-learning between them. this was not possible anymore during the lockdown. the collection of biological data was also influenced by the direct surroundings of the students. students living in an urban area were potentially at a disadvantage compared to students in the countryside. however, because we included the photo quiz module at the beginning of the lockdown, every student could continue the activity. figure 4 shows, for every group, the proportion of points acquired either with the quests collection or the photo quiz. we can see that the dual system allowed students to choose different strategies, to adapt to their individual lockdown conditions. we also observed a strong trend toward the collection of plant-related quests by the students ( fig. 3c & d) . this is probably due to the fact that, in an urban setup, plants are easier to find that animals. for an inexperienced naturalist, it is also probably easier to take pictures of plants than animals that have a tendency to escape. all the pictures can be viewed interactively at the address http://2020.quovidi.xyz overall, we observed a high correctness in the students picture submissions ( fig 5a) . for the treasure hunt and the picture collection, only 10% and 14% of the quests (for the animal and plant, respectively) were assessed as incorrect by ourselves. one reason for such a high accuracy from the students might be the high level of engagement required by the activity. they have to learn the vocabulary and discuss with other students, and go outside often in groups to find what they have identified as appropriate for a quest submission. in the icap framework [3] , we believe this corresponds to the "interactive learning" level, enabling the highest learning capabilities. interestingly, we also observed a much lower accuracy for the photo quiz ( fig. 5b ). for that activity, 37% and 38% of the evaluations by the students (for the animal and plant, respectively) were incorrect. this can be due to several factors. first, contrary to the treasure hunt in itself, the evaluation activity requires a lesser level of engagement by the student. the activity is indeed "reduced" to click on a button in front of a computer screen. second, depending on the quality of the picture to evaluate, said evaluation could be challenging. we tried to keep only good pictures for that activity, but the quality remained nonetheless variable. overall, the activity was very well appreciated by the students. with a few exceptions, students like going outside to observe their surroundings and collect the quests. in a survey performed after the activity ( fig. 6 ), 125 students reported to like the activity and have the feeling to have learned during it. many students spontaneously expressed their enthusiasm for this activity (tab. 3). selected comments from the students "great activity to learn new concepts and look at our environment in a different way. " "i think the game is fun and interactive, it's a great way to learn by seeing things "in real life" and also to decipher the quests. " "very nice way to propose the course, it pushes the students to discover the surrounding nature in a playful way. " the quovidi platform was created for several reasons. we wanted students to learn and know specific plant and animal vocabulary, but we did not want to just give them a list of words to be memorized and repeated. we also wanted them to explore and learn to observe their direct environment. we wanted to show them that you do not need to go to a tropical forest to be able to see a great diversity of plant and animal forms and species. we wanted to spark a strong interest in their surrounding natural world. finally, we were also working with strong practical constraints. we needed to design an activity that was scalable for hundreds of students, without the need to increase the number of educators. this was possible, thanks to the current technologies (camera, mobile network and gps localisation) available in almost every mobile phone. with the creation of the web-platform for quovidi, we have met all those goals. the treasure hunt (and to a lesser extent the photo quiz) strongly motivates students to learn and remember the different technical terms used in the quests. then they have to apply these new terms directly in the field. the gamification process (quests, score points, personal progress panel and scoreboard between all the groups) is also a strong incentive to engage in the activity. the activity is also highly scalable. the number of participants is, from a technical point of view, only limited by the capacity of the server on which the platform is installed. the main limitation remains the expert correction step. as every single picture needs to be validated, the evaluation can quickly require a lot of time from the educator, even though we tried to make the process as efficient as possible. we hope in the future that the platform would benefit from advances in artificial intelligence algorithms to help correct the images (see below). finally, the activity is completely decentralised, which has been a great asset during the covid-19 crisis. students can collect quests at any time and place, making it easy to adapt to every individual situation. if they cannot go outside, or are not in a nature-rich environment, they can still participate in the activity via the peer evaluation module. from the educator point of view, all the management and corrections can be done from anywhere, as long as they have access to a computer and an internet connection. as such, the platform was a real asset during the lockdown period (13 march to 8 of june in belgium), as it enabled us to continue the activity almost seamlessly. similarly to citizen science projects, the use of our platform allows the collection of large numbers of geotagged, dated images of plant and animal structures. by helping create such a database over the years, the students are taking an active role in creating a valuable research ressource. this in itself is viewed by the students as a motivational element of the activity. such databases could be re-used in different ways. from an educational point of view, the images collected could be used to create a quiz to rehearse the vocabulary the following year. the student would therefore create their own teaching and rehearsal material. an example of a quiz created with the students pictures is visible here : http://quiz.quovidi.xyz . from a research point of view, an ever growing database of annotated plant and animal pictures (describing either organ, species or groups), on a limited and well defined area would be a valuable resource. as each record of the database has been validated by an expert (the educators), such a database could be used in research projects. another interesting valuation of the database would be to reuse it to train deep learning recognition algorithms. again, given the size and potential growth of the database, it will be an interesting resource to train machine learning models to recognise plant and animal structures. such models could, in turn, be integrated into the platform to help with the correction. so far, we use the quovidi framework within a single classroom (even if it was a very large one). since the activity is entirely centralised online, we could imagine collaboration between remote classrooms. students from different regions, countries or continents could participate in the same activity, hence increasing the degree of diversity of the observations. here we exemplified the use of our platform with a biological treasure hunt. students were asked to find, in the field, plant and animal structures. however, due to its flexibility, the platform could be used to organise large scale treasure hunts in any context. it could be used in architecture, design or geology classrooms, with quests related to different building structures, street art or rock, respectively. it could be used with children, with simplified quests, or with more advanced students, with more complex ones. in short, we expect the concept could be used in any context to deal with structures present in the "outside" world. we presented in this manuscript a new open-source web platform for the organisation for large tresor hunt, quovidi. during the spring 2020, in the midst of the covid-19 crisis, we successfully used the quovidi platform with more than 300 students, and allowed the collection of more than 6000 geotagged plant and animal pictures. the decentralised nature of the platform enabled us to ensure a continuity in our teaching, despite the nation-wide lockdown. we expect quovidi to be of interest for any teaching activity focused on the identification of real-world structures. quovidi is available at the address http://www.quovidi.xyz active learning increases student performance in science, engineering, and mathematics translating the icap theory of cognitive engagement into practice the icap framework: linking cognitive engagement to active learning outcomes increased structure and active learning reduce the achievement gap in introductory biology kapp bkm. games, gamification, and the quest for learner engagement. in: main [internet the effect of gamification on motivation and engagement create dashboards with shiny: web application framework for r shinywidgets: custom inputs widgets for shiny twitter bootstrap components for shiny shiny ui widgets for small screens dbi: r database interface sqlite" interface for r advanced graphics and image-processing in r exif image data in r easily install and load the "tidyverse dates and times made easy with lubridate streamlined plot theme and plot annotations for "ggplot2 formattable: create "formattable" data structures dt: a wrapper of the javascript library "datatables tools for splitting, applying and combining data leaflet: create interactive web maps with the javascript "leaflet" library feel: a french expanded emotion lexicon. language resources and evaluation apache license, version 2.0 | open source initiative quovidi, then called biogo, was one of the laureates of the "prix wernaers pour la vulgarisation scientifique" in 2020. original draft x x x x x key: cord-021897-yeih3tfo authors: page, stephen j. title: tourism today: why is it a global phenomenon embracing all our lives? date: 2011-10-28 journal: tourism management doi: 10.1016/b978-0-08-096932-9.10001-8 sha: doc_id: 21897 cord_uid: yeih3tfo nan the new millennium has witnessed the continued growth of interest in how people spend their spare time, especially their leisure time and nonwork time. some commentators have gone as far as to suggest that it is leisure time -how we use it and its meaning to individuals and familiesthat defines our lives, as a focus for non-work activity. this reflects a growing interest in what people consume in these non-work periods, particularly those times that are dedicated to travel and holidays which are more concentrated periods of leisure time. this interest is becoming an international phenomenon known as 'tourism': the use of this leisure time to visit different places, destinations and localities which often (but not exclusively) feature in the holidays and trips people take part in. the world travel and tourism council (wttc) estimate that travel and tourism as economic activities generates around us$6 billion, which is expected to grow to us$10 billion by 2015. at a global scale, travel and tourism today: why is it a global phenomenon embracing all our lives? 1 tourism supports around 235 million jobs: this is equivalent to 8 per cent of world employment and 9 per cent of world gdp. therefore, the growing international significance of tourism can be explained in many ways. in an introductory text such as this, it is important to stress at the outset the following types of factors and processes in order to illustrate the reasons why tourism assumes an important role not only in our lives but also globally: • tourism is a discretionary activity (people are not required to undertake it as a basic need to survive, unlike consuming food and water) • tourism is of growing economic significance at a global scale, with growth rates in excess of the rate of economic growth for many countries • many governments see tourism as offering new employment opportunities in a growing sector that is focused on service industries and may assist in developing and modernizing the economy • tourism is increasingly becoming associated with quality of life issues as it offers people the opportunity to take a break away from the complexities and stresses of everyday life and work -it provides the context for rest, relaxation and an opportunity to do something different • tourism is becoming seen as a basic right in the developed, westernized industrialized countries and it is enshrined in legislation regarding holiday entitlement -the result is many people associate holiday entitlement with the right to travel on holiday • in some less developed countries, tourism is being advocated as a possible solution to poverty (described as 'pro-poor' tourism) • holidays are a defining feature of non-work for many workers • global travel is becoming more accessible in the developed world for all classes of people with the rise of low-cost airlines and cut-price travel fuelling a new wave of demand for tourism in the new millennium. this is potentially replicating the demand in the 1960s and 1970s for new popular forms of mass tourism. much of that earlier growth was fuelled by access to cheap transport (i.e. the car and air travel) and this provided new leisure opportunities in the western world and more recently in the developing world and newly industrializing countries • consumer spending on discretionary items such as travel and tourism is being perceived as a less costly item in household budgets. it is also much easier to finance tourism with the rapid rise in credit card spending in developed countries, increasing access to travel opportunities and participation in tourism • technology such as the internet has made booking travel-related products easy and placed it within the reach of a new generation of computer-literate consumers who are willing to get rid of much of the traditional ritual of going to a travel agent to book the annual holiday. such technology now opens many possibilities for national and international travel at the click of a computer mouse and to check-in for a flight via a mobile phone. it is evident that tourism is also becoming a powerful process affecting all parts of the globe. it is not only embraced by various people as a new trend, a characteristic or defining feature of people's lives, but is also an activity in which the masses can now partake (subject to their access to discretionary forms of spending). this discretionary activity is part of wider post-war changes in the western society with the rise in disposable income and spending on consumer goods and services. yet tourism is not just a post-war phenomenon as it can be traced back through time as shown in chapter 2. this highlights how important tourism was in past societies as well as the historical processes of continuity and change which help us to understand tourism development throughout the book. the first major wave of growth in consumer spending was in home ownership, then in car ownership and, then, in accessing tourism and international travel. in fact international travel (and domestic travel, i.e. within a country) is a defining feature of the consumer society. whilst the car has given more people access to tourism and leisure opportunities within their own country, reductions in the price of aeroplane tickets have made international travel and tourism products and services more widely available. for example, the number of air travellers in the uk is expected to rise to 475 million by 2030. this is not without its environmental cost. there is a growing global concern about the ability of the earth's environment and resources to sustain the continued expansion of economic activity, including tourism. whilst scientists have pointed to these concerns since the 1960s, these environmental issues have only really begun to permeate government and people's thinking since the rise of global concerns over climate change and the international kyoto treaty seeking to address greenhouse gas emissions. tourism is the centre stage in these concerns because travel for leisure purposes is not a fundamental necessity, and it contributes to co 2 emissions through the consumption of fossil fuels used to transport people on holiday, at the destination and in the accommodation they use. transportation causes around 75 per cent of the co 2 emissions generated by tourism, with aviation responsible for around 40 per cent of these emissions. improving energy efficiency in transportation may be expected to generate a reduction of 32 per cent in the emissions per passenger kilometre between 2005 and 2035. however, the quantity of emissions varies depending on the mode of transport used, with long-haul travel the greatest contributor to highly emissionintense trips. the issue of tourist travel and its global environmental effect through pollution is a thorny issue since tourism is internationally significant and has an important role in society, as we have already seen. there is an almost unanimous reluctance among government policy-makers to directly limit or restrict tourist travel due to its economic effects on destination areas. consequently, many prefer to adopt the politically acceptable and palatable adaptation strategies -seeking to adapt human tourism today: why is it a global phenomenon embracing all our lives? 1 behaviour and destinations to the effects of climate change (see box 1.1). many people openly admit to being supportive of 'green' and 'sustainable' principles but are unwilling to sacrifice their annual or additional holiday to reduce carbon emissions: likewise, few are willing to sacrifice an overseas destination for a less carbon consumptive and polluting domestic holiday. this assumes a more interesting dimension when one sees some sections of the tourism industry responding to consumer interest in green issues, by offering more 'green' and 'sustainable' holidays, recognizing a business opportunity. critics have labelled this harnessing of green issues as one way of gaining a competitive edge without a complete commitment to implementing sustainability principles in their business practices as 'greenwash' (see table 1 .1). this reflects the fact that tourism in this respect is a phenomenon that is constantly evolving, developing and reformulating itself as a consumer activity. tourism, as a consumer activity, is constantly being developed by the tourism industry and individual businesses, as marketing is used to develop new ideas, products and services and destinations. the challenge for the tourism industry is in adopting new ideas developed in research, such as service dominant logic (see shaw et al., 2011 for more detail) which may assist, with the use of social marketing techniques, to adapt human behaviour so that they extend the daily activities which climate change has become a dominant theme in the analysis of the future for small island nations which are little more than a metre above sea level. this has become a major problem for governments when the scale of sea level change is set against natural changes in the land level, which is sinking at a rate of around less than a centimetre per year. however, this means that in less than 100 years some island states such as the maldives may be flooded and therefore uninhabitable. the maldives is a collection of 1200 small islands (198 of which are inhabited) and it is dependent upon tourism as its main source of external earnings, accounting for over 28 per cent of gdp and almost 60 per cent of foreign earnings' receipts. the dependence upon tourism has meant that the country's 600 000 international visitors each year are a key source of revenue for the country's economy and should climate change combine with sea level rises to accelerate the pace of change, the country's tourism industry could be completely eradicated. therefore in spite of the country's natural beauty and 80 tourist resorts located across 80 different atolls (i.e. small islands that are just above sea level) its competitiveness as a destination may well be threatened by natural environmental changes. to address these threats, the capital male has built a 3 m sea wall for just one island and other islands in the maldives suffer periodic flooding. despite these major challenges, the country's government is seeking to try and mitigate the worst impacts of climate change, as its resources are very limited and the scale of the problem is huge. it is a story that can be repeated across many similar island archipelagos across the south pacific where climate change may accelerate the pace of sea level rises putting the livelihoods and entire destination in peril for the future. embrace sustainability ideals (e.g. recycling, reuse and minimizing the use of natural resources) to their holiday-taking behaviour. of course, the cynic may argue that the most sustainable form of tourism is none at all if you are serious about your own footprint on the planet. for the tourism sector, they have embraced new ideas (including in some cases sustainability) and pursued strategies focused developing niche products reflecting the way tourism has developed a more specialist focus (see table 1 .2). tourism appeals to the human imagination. as an activity it knows no bounds: it is global and it affects the environment it occurs in, the people who host it, the economies it seeks to benefit and the tourists who consume it as an experience, product and an element of their lives. with tourism having this all-embracing role, it is no surprise that many commentators, researchers and governments have agreed on the need to manage it as a process and activity, especially since it has the potential to snowball and grow out of proportion if it is not managed. therein lies the basic proposition of this book -tourism needs managing if it is to be successful and beneficial rather than a modern-day scourge. tourism and its ability to be sustainable as an activity have been major growth areas of research since the 1990s. the guiding principles of sustainable tourism are based on the management of resources, the environment and economy and society/its culture for the long-term so they are not compromised or damaged by tourism development. a number of key studies exist which provide a very wide ranging overview of the subject's development: krippendorf, j. (1987) the holiday-makers. oxford: butterworth heinemann. this landmark study questioned the necessity of long-haul travel and the impact of tourism including the damage it caused to the environment. this is a complex but critical review of the sustainability debate which challenges current thinking and many of the conventional ideas that tourism can easily be translated into a sustainable activity, particularly in less developed countries. this report outlines many of the principles associated with setting out the principles which can be harnessed to try and make tourism sustainable. yet one of the fundamental problems in seeking to manage tourism is in trying to understand what it is: how it occurs, why it occurs, where it does, the people and environments that are affected by it and why it is a volatile activity that can cease as quick as it can start. these types of questions are what this book seeks to address. it will also look at why tourism as a consumer activity is built on dreams, images and what people like to do; this is notoriously difficult to understand as it involves entering the realms of psychology and the mind of the individual tourist. furthermore, these psychological elements are bound up in notions of enjoyment, feelings, emotions and seemingly intangible and unseen characteristics. the issue is further complicated by the way in which an individual's tastes and interests change throughout their life. in other words, being a tourist is based on the principle of non-work and enjoyment of one's free time in a different locality, and results in an experience, a treasured memory and something personal which develops through our life course. tourism is a dynamic phenomenon and a highly trend-driven activity in a post-modern society where travellers constantly seek new and diverse experiences. this has led the tourism sector to harness marketing techniques to create different products and experiences to very specific market segments based on consumers' interests and values. a range of some of the key trends and developments in recent years are listed below with a brief explanation of their underlying philosophy and examples. slow travel travel to a destination and savouring the journey by not flying, such as taking the train or bicycle so as the rush and stress is taken out of the travel experience so it is slowed down why study tourism? is it just about enjoyment and holidays? tourism and its analysis have become a relatively recent field of study among academics, researchers and commentators. some of the very early student textbooks on tourism (see table 1 .3) can be dated to the early 1970s (although there are examples of other reviews of tourism dating to the 1930s, 1940s and 1950s), with a second wave being produced in the 1980s and then a massive explosion in the late 1980s and 1990s as tourism education and training expanded worldwide. since the 1990s, a wide range of more specialist and niche books have been published on particular aspects of tourism research. there are a range of commonly recognized problems in studying tourism, a number of which are important to the way in which we understand whether it is just about enjoyment and holidaytaking: • tourism is a multidisciplinary subject which means that a wide range of other subjects, such as psychology, geography, economics, to name but a few, examine it and bring to it a range of ideas and methods of studying it. this means that there is no overarching academic agreement on how to approach the study of tourism -it really depends on how you are looking at tourism, and the perspective you adopt which determines the issues you are interested in studying • this has led to a lack of clarity and definition in how to study tourism, something that other researchers have defined as reductionism. what this means is that tourism is normally defined by reducing it (hence 'reductionism') to a simple range of activities or transactions (i.e. what types of holidays do people choose? or how do people purchase those holidays?) rather than by focusing on the framework needed to give a wider perspective or overview of tourism. these problems often compound the way people view tourism as a subject, emphasizing the holiday or enjoyment aspects of travelling (in one's spare time or on business) as the defining features or reference point of tourism. to the general public tourism is something everyone knows about -it is something many have engaged in and so have an opinion on what it is, its effects and widespread development. admittedly, tourism is about pleasure and enjoyment, but its global growth and expansion are now creating serious societal problems and issues; a fundamental understanding of tourism is required if we are to manage and control the impacts and problems it can cause. some critics argue that tourism epitomizes the extreme of post-modern consumption in a society that spends on travel and tourism because it can and not for an intrinsic need for holidays as access to travel is, in relative terms, very cheap and affordable for many. one way of beginning to understand that tourism is more than holidays and enjoyment is to think about why tourism is so important in modern society (i.e. its social, cultural and economic significance) by looking at an important process which has led to the demand for it -the rise of the leisure society. tourism is now widely acknowledged as a social phenomenon, as the nature of society in most advanced developed countries has now changed from one which has traditionally had an economy based on manufacturing and production, to one where the dominant form of employment is services and consumer industries (i.e. those based on producing consumer goods and services). at the same time, many countries have seen the amount of leisure time and paid holiday entitlement for their workers increase in the post-war period so that workers now have the opportunity to engage in the new forms of consumption such as tourism. these changes have been described as being part of what has been termed as the leisure society, a term coined in the 1970s by sociologists. they were examining the future of work and the way in which society was changing, as traditional forms of employment were disappearing and new service-related employment, increased leisure time and new working habits emerged (e.g. flexi-time and part-time work). some commentators described this as a 'leisure shock' in the 1980s since many workers were still not prepared for the rise in leisure time and how to use it. as society has passed from the stage of industrialization to one now described as post-industrial, where new technologies and ways of communicating and working have evolved, sociologists such as baudrillard (1998) in the consumer society: myths and structures, have argued that we have moved from a society where work and production have been replaced by one which leisure and consumption now dominate. this has been reflected in social changes, such as the rise of new middle classes in many developed and developing countries, and these middle classes have a defining feature, which is the concern with leisure lifestyles and the leisure society consumption. the new-found wealth among the growing middle class has been increasingly spent on leisure items and tourism is an element of this (e.g. in 1911, 1 per cent of the population had 70 per cent of wealth; this dropped to 40 per cent in 1960 and 23 per cent in 2002 in the uk). the international growth in holidaytaking is directly related to this new middle class. the increasing mobility of this group has been reflected in a massive growth globally in their propensity to travel and the growth of a society focused on leisure, of which tourism is prioritized as a key element of their household budgets and as a form of conspicuous consumption as the following statistics suggest: • factors promoting these changes include cheaper air fares and changing patterns of personal expenditure. this snapshot of the uk shows that tourism is a major element of the leisure spending of households and tourist travel to the uk is a major driver of the economy. the growing significance of travel and tourism in the household spending reflects what researchers have described as 'leisure lifestyles'. interest in tourism in europe, north america and other parts of the world has been given an added boost by the impact of new technology such as the internet and the worldwide web, which has rendered knowledge and awareness of tourism and the opportunities to travel worldwide more accessible. the worldwide web has been used as a medium to portray travel options and the product offerings of destinations, so that people can search and explore travel options at a global scale from the ease of a computer terminal. in europe, the impact of this new technology in the early years of the twenty-first century has generated a new tourism boom akin to the rise in international tourism in the 1970s, with new forms of technology and the supply of cheaper forms of travel (i.e. the low-cost airlines) fostering this demand. over 90 per cent of some low cost airline bookings are now made online which illustrates the power of the internet and its role in reaching a new customer base in the tourism sector. this has given rise to the rise of e-tourism, which is the digitization 1 of all elements in the tourism supply chain 1 , whereby the supply and demand for tourism can be met through new virtual forms of distribution such as the worldwide web, as opposed to conventional methods such as travel agents and paper brochures. this has certainly revolutionized tourism and the access to travel knowledge and information, hitherto largely within the confines of travel agents and travel organizers: now everyone can be their own travel agent if they have access to the technology. other commentators have also pointed to the changing sophistication of tourists as consumers, especially the middle classes with their pursuit of authentic and unique experiences. this is part of what pine and gilmore (1999) identified as the experience economy which is the next stage in the evolution of society from a service economy. they argue that businesses need to create experiences which create a sensation, can personalize the experience to build a relationship with the consumer and they suggest four areas of experience that we need to focus on: • entertainment • education • esthetic (i.e. an ability to immerse oneself in something) and • escapism in what is consumed. this has major implications for the types of tourism experience we develop now and in the future and it has gained momentum with the growth of the internet that now allows consumers to seek out these experiences globally. the internet e-tourism is only the first stage of the internet's impact upon tourism. the first wave of internet technology created an online travel community where tourism businesses were able to market and communicate with consumers through electronic media. this has been followed by a new wave of web-based communities known as web 2.0 (also described as computergenerated media or social media) where the online content is created by online users and made available to other users via the web 2.0 interactive technology. the importance of this technology is that it allows consumers to communicate about social themes such as holidays and travel. so the increasing use of the internet to make bookings and reservations for travel online has been combined with consumer ratings and reviews online through travel sites such as tripadvisor.com. therefore, many of the previous principles of travel planning, where the advice and knowledge of travel agents was seen as a key determinant of holiday decision-making have now been replaced by the technological power of the internet. access to and use of internet technology is increasing and one important feature which many studies confirm is that this technology is increasingly used to search out and peruse travel options as well as for making bookings. with these issues in mind, attention now turns to what is meant by the terms 'tourism', 'tourist' and 'travel'. attempts to define tourism are numerous and very often the terms 'travel' and 'tourism' are used interchangeably. according to the international organization responsible for tourism, the world tourism organization (un-wto): this seemingly straightforward definition has created a great deal of debate. in fact, controversy has surrounded the development of acceptable definitions since the league of nations' attempt to define a tourist in 1937 and subsequent attempts by the united nations conference in 1963 which considered definitions proposed by the then iuoto (now un-wto). there have also been attempts to clarify what is meant by the term 'visitor' as opposed to 'tourist' and the distinction between tourists who travel within their own country (domestic tourists) and those who travel to other countries (international tourists). what the debates on defining tourism at a technical level show is that it is far from an easy task in agreeing what constitutes a 'tourist'. for example, should we include someone who is a visitor staying in a second home?: they are technically away from their home, but are staying in another form of property they own. similarly, how far away from your home area must you travel before your activity is deemed tourism? a further problem is associated with the category of cruise ship passengers who dock at a port and visit briefly, not staying overnight, or cross-channel trippers who may cross an international boundary but then return within a day and do not stay overnight. to try and encompass many of these anomalies and problems, the un-wto produced guidelines and a useful categorization for defining a tourist, which is shown in figure 1 .1. what is increasingly obvious is that new forms of research on tourism are needed to understand how the phenomenon loosely defined as tourism is evolving as it is far from static. for example, research on tourism and migration has identified the short-term migration of the elderly who winter in warmer climatessuch as the uk pensioners who overwinter in the mediterranean -as a new type of tourist. these patterns of tourism migration incorporate owners of second homes, tourists and seasonal visitors who spend two to six months overseas in locations such as tuscany, malta and spain. for example, 328 000 people own a second home in the uk and 178 000 tourism is defined as the activities of persons travelling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes not related to the exercise of an activity remunerated from within the place visited. the use of this broad concept makes it possible to identify tourism between countries as well as tourism within a country. 'tourism' refers to all activities of visitors, including both 'tourists (overnight visitors)' and 'same-day visitors'. (www.world-tourism.org) 1 have purchased overseas properties. in the usa, estimates of domestic second-home ownership range between 3.6 million and 9.2 million properties, the majority of which are located in coastal or rural areas. this pattern of seasonal tourism and migration also generates flows of people known as 'visiting friends and relatives', and these are somewhat different to the conventional images of package holidaymakers destined for these locations in europe. in the usa, a long-established trend of a family vacation is the holiday home. some commentators also suggest that existing definitions of tourism are dated and are being challenged by new forms of tourism such as students engaging in a year abroad. therefore, the following definition of tourism might be useful where tourism is in the usa, there is a tendency still to use the term 'travel' when in fact 'tourism' is meant. what is clear is that tourism is associated with three specific issues: • 'the movement of people • a sector of the economy or an industry • a broad system of interacting relationships of people, their needs [sic] to travel outside their communities and services that attempt to respond to these needs by supplying products'. chadwick, 1994) the field of research on human and business activities associated with one or more aspects of the temporary movement of persons away from their immediate home communities and daily work environments for business, pleasure and personal reasons (chadwick 1994: 65) . from this initial starting point, one can begin to explore some of the complex issues in arriving at a working definition of the terms 'tourism' and 'tourist'. probably the most useful work to provide an introduction to tourism as a concept and the relationship with travel is burkart and medlik's (1981) seminal study tourism: past, present and future. this identified the following characteristics associated with tourism: • tourism arises from the movement of people to and their stay in various destinations • there are two elements in all tourism: the journey to the destination and the stay including activities at the destination • the journey and the stay take place outside the normal place of residence and work, so that tourism gives rise to activities that are distinct from those of the resident and working populations of the places through which tourists travel and in which they stay • the movement to destinations is of a temporary, short-term character, with intention to return within a few days, weeks or months • destinations are visited for purposes other than the taking up of permanent residence or of employment remunerated from within the places visited. source: burkart and medlik (1981: 42) all tourism includes some travel but not all travel is tourism, while the temporary and short-term nature of most tourist trips distinguishes it from migration. but how does tourism fit together -in other words how can we understand the disparate elements? one approach is to look at tourism as an integrated system, which means that one has to ask how tourism is organized and what the defining features are. the most widely used framework is that developed by leiper (1990 -see hall and page, 2010 for a posthumous review of his work) who identified a tourism system as comprising a tourist, a traveller-generating region, tourism destination regions, transit routes for tourists travelling between generating and destination areas, and the travel and tourism industry (e.g. accommodation, transport, the firms and organizations supplying services and products to tourists). this is illustrated in figure 1 .2 and shows that transport forms an integral part of the tourism system, connecting the tourist-generating and destination regions together. thus, a 'tourism system' is a framework which enables one to understand the overall process of tourist travel from both the supplier and purchaser's perspective (known respectively as 'supply' and 'demand') while identifying the organizations which influence and regulate tourism. it also allows one to understand where the links exist between different elements of tourism, from where the tourist interacts with the travel organizer (travel agent or retailer), the travel provider (airline, or mode of transport), the destination area and tourism sector within the destination. this approach is also helpful for understanding how many elements are assembled by 1 the tourism sector to create an experience of tourism. one major element in this experience of tourism is the tour, which is a feature of holidays and the use of leisure time. the tour, holidays, leisure time and the destination what is evident from leiper's model of the tourism system is that the tour -which is a trip or travel anywhere for pleasure, leisure or businessis a vital element. the tour is an underpinning feature of tourism, a prerequisite for tourism to occur -the consumer has to be brought to the product or experience, and has to travel, and it is a reciprocal event -the traveller travels out and back. transport and single or multiple locations are involved. the conventional definition of touring inevitably implies travel to one or more places, called 'destinations'. a destination typically comprises attractions (e.g. natural and man-made), need to be accessible, have available packages to attract visitors, provide ancillary services such as tour guides and have amenities such as accommodation and retailing. this notion of a destination is increasingly being used as a framework for tourism management by public sector organizations to understand how the visitor experience of a place can be developed and enhanced as well as how the synergies between businesses can be developed and the competitiveness of the destination can be improved. for the tourist, there are various forms of touring: the excursion by road or rail which may have a scenic element known as a touring route; some cruises, where the ship tours a range of destinations or ports of call. conversely, the excursion element may be something that the tourist undertakes at the destination on a day-trip basis or in the form of a more sustained trip, with a planned or unplanned itinerary. whilst the holiday is something which encompasses the entire experience or use of leisure time for a holiday, the tour is a distinct element of the holiday and has distinct travel patterns. these patterns contribute to the development of places as destinations which develop and grow through time. some researchers have attempted to explain the growth, stagnation and decline of tourist resorts such as spas in terms of a resort life cycle. the work of butler, published in 1980, suggested that resorts follow a specific cycle page, 1995 ; based on and modified from leiper, 1990) of growth. the initial exploration by tourists is followed by a period of involvement, often with patronage by a royal figure who started a trend towards visitation (e.g. king george iii visiting weymouth in england) or by its wider popularization as a resort for the elite to visit. this set the stage and created tourism tastes and fashions emulated by the visitors. the next stage of butler's model is development, followed by consolidation and then stagnation. at this point, the resort may decline or action may be taken by agents of development (i.e. an entrepreneur, the public sector or a combination of both) to rejuvenate the resort, and this rejuvenation is the last stage of the model. figure 1 .3 illustrates this pattern through time and shows the creation (i.e. birth) and decline (i.e. death) of resorts. although such models are highly generalized and simplify the reality of resort development, they are a starting point for the analyses of resorts such as spas through history. the model has also been used in recent years as a basis to try and understand what point specific destinations are in their life cycle, since the model follows the marketing concept of the product life cycle, where products may have definite or indefinite life courses. the same applies to tourist destinations which can decline when tourist tastes and patterns change and so fall out of favour and require a new focus or attraction to bring the visitors back. in view of these issues, which help to understand the nature of tourism as an entity, attention now turns to the scale, significance and importance of tourism as an international activity. once we agree a general definition of what tourism is, we can look for methods that add precision to the scale, volume and significance of tourism as a global activity. measuring tourism also helps to understand some of the problems which planners and decision-makers need to address in butler, 1980) tourism today: why is it a global phenomenon embracing all our lives? 1 planning for tourism and future growth scenarios. there are three basic considerations in trying to define tourism as an activity, which are: 1 what is the purpose of travel (e.g. business travel, holidaymaking, visits to friends and relatives)? 2 what time dimension is involved in the tourism visit, which requires a minimum and a maximum period of time spent away from the home area and the time spent at the destination? in most cases, this would involve a minimum stay of more than 24 hours away from home and less than a year as a maximum 3 what situations exist where some countries may or may not choose to include travellers, such as cruise passengers, travellers in transit at a particular point of embarkation/departure and excursionists who stay less than 24 hours at a destination, as tourists? there are five main reasons why measuring tourism is important: 1 to understand why and how significant it is for certain destinations, countries and regions in terms of the scale and value of the visitors 2 to understand how important it is for countries in terms of their balance of payments, as it is an invisible export that generates foreign currency and income 3 to assist the tourism industry and governments in planning for and anticipating the type of infrastructure which is required for tourism to grow and prosper 4 to assist in understanding what type of marketing is needed to reach the tourist as a consumer, and what factors will influence tourists to visit a country or destination 5 to help the tourism industry make decisions about what type of action is needed to develop tourism businesses. at a general level, measuring tourism through the collection, analysis and interpretation of statistics is essential to the measurement of the volume, scale, impact and value of tourism at different geographical scales from the global to the country level down to the individual destination. at the simplest level, this is shown in figure 1 .4, which demonstrates the trends in global tourism since 1950 and forecasts to 2020. part of this turbulence, as glaeßer (2006) notes, is the impact of natural catastrophes on tourism. for example, in the twentieth century there have been 50 000 natural disasters but between 1990 and 2005 there have been 500-700 such catastrophes each year. these events have periodically interrupted or at worst devastated the tourism industry (e.g. the earthquake that devastated haiti in 2009), contributing to the notion of turbulence in tourism activity. in other words, a range of factors impact upon visitor arrivals at an international level, because tourism is a very fickle activity (i.e. it is very vulnerable to the external factors mentioned above which act as deterrents to travel) and adverse events can act as shock waves which send ripples across the world and impact upon people's willingness to travel for pleasure reasons. this is because tourism needs relative stability for such activity to occur and the vulnerability to shock effects has been described as volatility in tourism demand which reacts very quickly to these crises or shock events such as wars, currency fluctuations and political instability. tourism also responds to very positive factors such as hosting the olympic games which may lead to a sudden change in the volume of visitors. one of the most recent shock events that have impacted on global tourism is the global credit crunch. whilst this has had different types of impacts on various tourism markets (the most substantial on business travel), its continued existence has led to a global decline in visitor arrivals internationally. in addition, in 2008, the effect of the credit crunch was compounded by the outbreak of a global pandemic associated with swine flu (see figure 1 .5) which initially developed in mexico and spread by travellers returning to their home areas or by visiting new areas so that a number of fatalities occurred in the affected countries as shown in figure 1 1,800,000 1 9 5 0 1 9 6 0 1 9 6 5 1 9 7 0 1 9 7 5 1 9 8 0 1 9 8 5 1 9 9 0 1 9 9 5 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 2 0 0 9 2 0 1 0 2 0 1 5 2 0 2 0 france, spain, the usa, china, italy, uk and germany • more established destinations in north-western europe and the usa have seen slower growth compared to emerging regions such as africa, n. e. asia, eastern europe, s. e. asia and the middle east. what these rates of growth mean for individual destinations can be seen in web case 1.1 which examines vietnam. but one of the enduring problems of tourism statistics are that they are an incomplete source of information because they are often only an estimate of the total pattern of tourism. in addition, such statistics are often dated when they are published because there is a significant time lag in their generation, analysis, presentation and dissemination. this is because many published tourism statistics are derived from sample surveys with the results being weighted or statistically manipulated to derive a measure which is supposedly representative of the real-world situation. hence, many tourism statistics at a country or regional level often state they are estimates of tourism for this reason. in reality, this often means that tourism statistics may be subject to significant errors depending on the size of the sample. the typical problems associated with measuring tourism are as follows: • tourists are a transient and highly mobile population making statistical sampling procedures difficult when trying to ensure statistical accuracy and rigour in methodological terms • interviewing mobile populations such as tourists is often undertaken in a strange environment, typically at ports or points of departure or arrival where there is background noise which may influence responses • other variables such as the weather may affect the responses. source: latham (1989) even where sampling and survey-related problems can be minimized, such tourism statistics have to be treated carefully as they may be influenced by how the tourist was measured and the type of approach used. the main ways of measuring tourists through surveys are as follows: • pre-travel studies of tourists intended travel habits and likely choice of destination (intentional studies) • studies of tourists in transit to provide information on their actual behaviour and plans for the remainder of their holiday or journey (actual and intended studies) • studies of tourists at the destination or at specific tourist attractions and sites, to provide information on their actual behaviour, levels of satisfaction, impacts and future intentions (actual and intended studies) • post-travel studies of tourists on their return journey from their destination or on-site experience, or once they have returned to their place of residence (post-travel measures). such studies can also be used to examine different facets of the tourist as the following three approaches suggest: • measurement of tourist volume, enumerating arrivals, departures and the number of visits and stays • expenditure-based surveys which quantify the value of tourist spending at the destination and during the journey • measurement of the characteristics and features of tourists to construct a profile of the different markets and segments visiting a destination. in the commercial world, tourism data are also collated by organizations that specialize in its collection and analysis including market research companies. tourism consultants may also be commissioned specifically to collect data for feasibility studies of tourism developments or new business opportunities and much of the information remains confidential to the client due to its commercial sensitivity. but in most cases, national governments collate tourism statistics through studies of domestic and international tourism which are then assembled by the un-wto. once we have an understanding of how tourism is measured and collated, then we can begin to think about what the patterns and trends in tourism mean at a global level and what the implications are, particularly in terms of the more critical issues of what forces are affecting tourism as a global activity. new forces affecting tourism -globalization, inequality and the developed and developing world when one looks at the patterns of tourism, and those areas which are growing in terms of international tourism, it is evident that the majority of outbound travellers are from the developed countries of europe and north america, australasia and the new middle class in many developing countries. in some cases, the tourists are travelling to developing countries where the standard of living often means the majority of the population lives at subsistence level or at a much lower standard than the visitor. the contrast in wealth between visitor and host is often very large and it highlights a clear inequality between those who have the disposable income to enjoy the luxury of international and domestic travel and the tourism employees who are working at low wage rates and in low-paid, unskilled jobs. this situation is made worse by the growing impact of globalization. globalization is a process associated with the growth of large international companies and corporations, which control various forms of economic development and production internationally from their host country, making goods and delivering services at a lower cost using low overheads and cheap labour in developing countries. tourism is no exception to this: large multinational hotel chains and tour operators use developing countries and destinations as the basis for their tourist product. in these situations, the economic linkages with the local community are limited, so that low-skill jobs and low economic benefits are traded off against the profits and economic benefits of tourism development being expropriated (i.e. returned) to the country of origin of the multinational firm. in many cases, the weakly developed nature of local economic linkages in developing countries' tourism economies means they are often trapped into such exploitative relationships because they do not have the indigenous capital or entrepreneurs to set up tourism businesses. a lack of education, know-how and power to negotiate with multinationals to new forces affecting tourism maximize the benefits for local people means that tourism can develop as a form of exploitation for such communities. this may mean that rather than importing foodstuffs, such as internationally recognizable brands, to meet the tastes of tourists, local products should be developed to nurture the linkages with the local economy, so local people may benefit. tourists bring their leisure lifestyles with them on holiday and these are increasingly consumptive and conspicuous. their spending power could be harnessed for the benefit of the local economy. a growing problem in many tourism destinations worldwide is that the growth of tourism and expropriation of its profits mean that the environmental resource base which is used to attract tourists (e.g. attractive beaches, wildlife and the cultural and built environment) is not invested in and may be spoilt. more and more, attention is turning to the extent to which tourism is a sustainable economic, social and environmentally based activity. that we should use the environment without conserving it for future generations is one of the central arguments in the sustainable tourism debate. this also raises the issue of inequalities related to tourism; for example, tourist use of local resources required by residents can destroy those resources and environmental quality. this means that local people, governments and international agencies have a responsibility to lobby and take action to ensure that tourism development which occurs in different countries and locations is not only sustainable but seeks to minimize negative impacts as far as possible. it should not marginalize vulnerable groups such as children and the local workforce: the international labour organization (ilo) has estimated that between 10 and 15 per cent of the tourism workforce worldwide comprised children who do not enjoy appropriate standards of labour and employment conditions (see the work of tourism concern at tourismconern.org.uk). among the common human rights abuses which tourism concern have highlighted are: the forced eviction of people to make way for tourism development; environmental damage resulting from tourism which impacts upon the resources people depend upon for their livelihoods; exploitation of tribal people as tourist attractions and poor levels of pay and poor working conditions for employees in the tourism sectors. tourism needs to be developed in an ethical manner so that exploitation is not its hallmark. this is a theme which will be returned to later in the book; at this point it is enough to emphasize that tourism development and activity not only needs to be socially and environmentally responsible, it must be sustainable and long-term rather than short term and exploitative (so that the goose that lays the golden egg is not killed off). the tourism industry needs to work with communities, local bodies and people to ensure that tourism is a win-win activity for everyone and is integrated into the local community rather than just exploiting its local assets. this may require a significant change in emphasis in the way tourism is developed and managed but it is an enduring theme, which is worth highlighting at different points in the book (see box 1.2 for more detail). tourists and tourism businesses have a greater responsibility to ensure that tourism is promoted as an activity which will not only enhance global understanding and interaction between people of different cultures and societies, but which will also promote dialogue, benefits and opportunities for the tourist, the host and the environment. so, in some situations, tourism may be a way of providing the stimulus and means for preserving and conserving endangered species and environments as well as providing benefits beyond those, which normally accrue to the tourism industry. tourism has to operate as a profitable activity, but for its long-term future, mutually beneficial relationships and links between the industry, people and the environment must exist to bring financial and sustainable benefits for all and enhance the reputation and image of tourism as a global phenomenon. this is the underlying basis of the pro-poor tourism lobby. in this way the welfare and benefits of tourism to tourists can also be extended to the host population and help to address many of the global inequalities which exist in the growing globalization of tourism activity as multinational enterprises seek to exercise greater control of the choice and nature of tourism being offered to consumers. although this book will not be able to address all of these issues, it is hoped that they will be at the forefront of the reader's mind so that they are aware of the implications of the tourism industry and its activities at a global, national and local level throughout the book. extreme poverty is a major problem for many developing countries who have a large proportion of their population living a subsistence lifestyle, often existing on less than $1 a day. at the same time, many of these countries have seen their tourism economies expand as tourists seek new destinations and governments embrace the expansion of this activity to generate foreign revenue. a considerable body of research from consultants and academics has arisen on how this expansion of tourism may be harnessed to address the development problems associated with poverty (see scheyvens, 2007 scheyvens, , 2011 mitchell and ashley, 2009 ). this new thinking has been described as pro-poor tourism which is designed to develop ways to maximize the benefits from tourism to raise local people out of poverty. this involves measures that will: encourage the employment of local people (as opposed to expatriate labour), to provide opportunities for local people to supply goods to tourists and tourism businesses and the creation of micro-enterprises so people can develop their own businesses. however, many obstacles have been identified in implementing pro-poor tourism strategies in less developed countries which include: a lack of awareness and understanding in poorer communities which limits their understanding of the opportunities available; a lack of skills and entrepreneurial talent to capitalize on the opportunities and access to finance to create new businesses focused on tourism as well as cultural concerns over how tourism may affect their way of life. where success stories of pro-poor tourism exist, these examples of best practice need to be shared so that tourism can be harnessed to address abject poverty through case studies of best practice which outline the principles and success factors associated with implementation of such an approach. this is vital if the benefits of tourism development are to be harnessed in the future to address poverty. tourism and management as a focus for the book a framework for the book the title of this book is tourism management and therefore it is useful to present an organizing framework for the book and what is meant by the term 'tourism management'. what is often seen and used as an ambiguous term is the word 'management'. therefore, in this section, the relationship of tourism with management and its meaning in the context of this book is examined. tourism and management as a focus for the book at a very general level, the word 'management' as applied to tourism refers to how tourism needs to be managed as a growing activity at a global, national and local level in order that its often contradictory forces (i.e. the pursuit of profit as a private sector activity and impact on the resource base it uses such as a beautiful coastline on a pacific island) are reconciled and balanced so that tourism develops and is pursued in a sustainable manner. this means there is a need to examine the basic principles associated with the term 'management' and how they can be integrated with tourism as an activity. the basic functions associated with management are: 1 planning, so that goals are set out and the means of achieving the goals are recognized 2 organizing, whereby the work functions are broken down into a series of tasks and linked to some form of structure. these tasks then have to be assigned to individuals 3 leading, which is the method of motivating and influencing staff so that they perform their tasks effectively. this is essential if organizational goals are to be achieved 4 controlling, which is the method by which information is gathered about what has to be done. each of these functions involves decision-making by managers, businesses, tourist destinations or organizations so that they can be harnessed to achieve the objectives and tasks associated with managing tourism. the word 'organization' is often used as an all-embracing term to refer to the type of tourism entity which is involved with tourism as a business or other level. these businesses are motivated by their involvement in tourism to make a profit and, therefore, the efficient organization and management of their activities are essential to ensure that company or organizational objectives are met. there is a school of management thought which argues that management only occurs when chaos occurs and that the function of management is to impose order and structure on that chaos. within organizations dealing with the tourism sector (e.g. travel agents, airlines, tour operators and associated businesses), resources are harnessed (e.g. employees, finance, capital, technology, equipment and knowledge) to provide an output, which in the case of tourism is normally a product or experience consumed by the tourist or service. this output is achieved through the management of the resources. managing tourism demand and supply: the perennial management challenge for tourism organizations one critical element of that management process is related to the way in which businesses have to address the following issues: • what should we produce as a business to meet a certain form of tourism demand? (i.e. should we produce an upmarket high-cost holiday package for ecotourists using tailor-made packages or aim for mass market, low-cost package holidays?) • how should it be produced? (i.e. should we contract in supplies to provide each element of the package product to reduce costs or should we produce each element to ensure quality control and consistency in product delivery?) • when, where and how should we produce the tourism product? (i.e. do we produce an all-year-round or seasonal tourism product?) • what destinations/places should be featured in the tourism experience? • what form of business or businesses do we need to produce the tourism services and products so that we meet demand? tourism businesses need to address these issues for their long-term viability and success or failure will depend upon the management of their organizations' resources to meet demand by consumers in an efficient and profitable manner. it is the concept of supply (i.e. what a business produces) which helps us to understand how the wide range of tourism businesses and organizations (and quite often businesses which do not see themselves as servicing tourists' needs such as taxi companies) combine to link the tourist with the services, experiences and products they seek in a destination. sessa (1983) categorized the supply of tourism services by businesses as follows: • tourism resources, comprising both the natural and human resources of an area • general and tourism infrastructure, which includes the transport and telecommunications infrastructure • receptive facilities, which receive visitors, including accommodation, food and beverage establishments and apartments/condominiums • entertainment and sports facilities, which provide a focus for tourists' activities • tourism reception services, including travel agencies, tourist offices, car hire companies, guides, interpreters and visitor managers. these 'elements of tourism' which combine at a destination highlight the scope of tourism supply, but a number of less tangible elements of supply (i.e. the destination image) also need to be considered. the business environment in which businesses operate can also have a major bearing on tourism supply. for example, in most countries tourism operates within a free market economy, and individual businesses operate in open competition. however, in some countries certain sectors of the tourism industry receive assistance from government through infrastructure provision, marketing and promotional support from tourist boards and other agencies. it is also apparent that when governments decide to promote inbound tourism to destinations (also see further web reading 1). the competitive environment which affects tourism businesses and their operation needs to be considered in relation to a number of underlying economic issues: • what competitive market conditions exist for a specific sector of tourism (i.e. the airline sector, hotel sector or attraction sector)? do conditions of monopoly, oligopoly (i.e. where a limited number of suppliers control supply) or other market conditions exist? • how many businesses are involved in these markets? what size are they? are they able to respond quickly to new competitive pressures, or are they characterized by complacency and an inability to redefine their operations in the light of aggressive competition? • do the businesses involved in tourism display patterns of market concentration, where a limited number of businesses dominate all aspects of production (i.e. from retailing through to supply of services and products in the destination such as in the uk tour operator market)? • what are the capital costs of entering a tourism market? are there high entry and exit barriers? for example, starting an airline has high entry and exit costs, requires a high level of technical know-how and large capital investment and ongoing finance to service the business. buying a guesthouse, on the other hand, has low entry costs and no barriers to entry in terms of technical competencies to be able to run and manage it and host visitors • what types of products already exist in the market? is there scope for innovation to develop new products without the risk of 'ambush marketing' by competitors who copy the idea and undercut the competition by loss-leaders to regain market share? aggressive marketing and a limited number of loss-leaders have characterized the low-cost airlines and privatized railways in the uk in an attempt by their owners to capture price-sensitive leisure travellers. in other words, is there scope for price discrimination in the market to differentiate a whole range of products? what these factors indicate is that the market conditions and business environment in which tourism operates are far from static. they are constantly changing, requiring businesses to adapt and to develop strategies to retain their market presence. for tourism businesses, recognizing these evolving patterns, new trends and the need for innovation (i.e. new ideas and products) to address market conditions re-emphasizes the importance of managerial skills in the supply of tourism products and services. this also highlights what mintzberg (1973) identified as the nature of managerial work in organizations -short-term coping, disparate activities and more concerned with brevity, variety and increasing fragmentation. tourism managers and businesses are no exception to this and mintzberg's research has an important bearing on how managers performed certain roles (see table 1 .4) labelled as interpersonal, informational and decisional roles. the ten managerial work roles which mintzberg identified illustrate the scope of activities 1 which operating and managing a tourism business require, as well as some of the complexities of how the individual business interacts with the wider body of interests conveniently labelled the 'tourism industry'. it also suggests how important prevailing market conditions are when they impact upon how a business operates, manages and responds to opportunities, threats and shortcomings in its own organization. yet to do this, a business needs also to understand its relationship to other tourism businesses. a convenient way to explain this is by using the tourism supply chain concept. as tourism is an amalgam of different interests, activities, stakeholders and businesses, the supply chain concept helps us to understand how different interests are functionally linked together to form a distinct method of service delivery. the supply chain concept originates in economics and has been used to explain how different businesses enter into contractual relationships to supply services, products and goods, and how these goods are assembled into products at different points in the supply chain. tourism is well suited to the concept of the supply chain because the product, service or experience that is consumed is assembled and comprises a wide range of suppliers. all too often our knowledge of the supply chain is quite restrictive, since a wide range of components are consumed in tourism including the use of bars, restaurants, handicrafts, food, infrastructure and related services. a schematic diagram of a typical tourism supply chain is shown in figure 1 .6. this shows that once the consumer has chosen a destination and product, the decision to purchase involves contacting a tourism retailer (e.g. a retail agent, a direct selling company or an internet-based seller such as www.expedia.co.uk). having chosen a booking medium and selected a package from a tour operator, the package is then assembled. the tour operator enters into contractual relationships with tourism suppliers such as airlines (although larger tour operators may also own their own charter or schedule airline), hotel operators and suppliers of associated services such as airport transfers. these suppliers, in turn, contract suppliers who service their business needs: in-flight caterers, airline leasing companies, airport terminal services (i.e. check-in services, baggage handling, flight controllers, customer service agents for visitors and those with special needs, such as the disabled). with so many organizations involved in the supply chain in relation to tourist spending and activity, it is clear that these are critical break or pressure points where the service provision could potentially fall down (see figure 1.7) . the business strategies, that travel companies can pursue to develop their supply of tourism services and products include: • focusing on core business (i.e. a holiday company focusing on selling holidays rather than being vertically integrated and operating its own airline and hotels) • seeking to diversify its products. the leading french holiday company club mediterranée (club med), which traditionally sold packages to its 120 holiday resorts, has used this strategy. since 1999 and its acquisition of jet tours (france's fourth ranked tour operator, which tourism today: why is it a global phenomenon embracing all our lives? 1 operated to 113 summer and 81 winter locations) it has diversified its operations to sell non-club med packages. rewe in germany has pursued a similar diversification strategy with its acquisition of a wider range of tour operating businesses in the long-and short-haul market • choosing to operate in all segments of the tourism market. tui has adopted this tactic and others such as kuoni are moving towards that goal • non-holiday companies may choose to enter the market: easyjet entered the cruise holiday business in 2005. to implement these business strategies, companies in the tourism industry have adopted marketing-related concepts such as branding to differentiate their products in an increasingly competitive marketplace. for example, club med relaunched its worldwide image to re-emphasize its famous name and association with consumers, and particularly its dominant position in the french market. thomas cook, now owned by the german company c&n touriste, has used its global image and historic association with pioneering tourism to continue its expansion throughout europe (see figures 1.8-1.10 ). there is also a debate among tourism researchers who argue that tourism is a unique sector in that it displays characteristics of partial industrialization which are explained more fully by leiper (1990: 25) where only certain organizations providing goods and services directly to tourists are in the tourism industry. the proportion of (a) goods and services stemming from that industry to (b) total goods and services used by tourists can be termed the index of industrialization, theoretically ranging from 100 per cent (wholly industrialized) to zero (tourists present and spending money, but no tourism industry). 1 what leiper's approach to the tourism sector shows is that managing the broad phenomenon called 'tourism' is complex for a number of reasons: • the tourism industry is not a homogenous sector or segment of the economy: it is made up of various organizations directly involved in tourism (i.e. those which directly service tourist needs) and those indirectly involved and so may be described as allied industries (i.e. food suppliers, retailers and other service providers) • some of the organizations directly involved in tourism are responsible for encouraging and promoting tourism development and marketing • the allied industries do not always see themselves as tourism-related enterprises • the destination or area which the tourists visit is not the sole responsibility of one business or group of businesses; usually the public sector intervenes to ensure that business objectives (i.e. profit and increasing 1 tourism numbers and revenue) are balanced with local needs and business interests (known as 'stakeholder interests') in relation to the resource base which tourism utilizes (i.e. beaches, attractions, the infrastructure and overall environment) • the public sector is responsible for trying to liaise, plan and manage these diverse group of interests that are associated with tourism as a phenomenon as well as having an underlying responsibility in many cases for the marketing and promotion of the destination. therefore, one can see how complex the management of tourism is when the interests and variety of organizations involved in tourism are considered and then the concept of partial industrialization is introduced. from this discussion, who is responsible for tourism management can be examined at a number of levels, although this is not an exclusive list but a range of illustrations: • at the individual business level, the manager(s) is (are) involved with the functioning and running of the enterprise • at the destination level, responsibility often lies with a public sector led agency such as a tourism department (either as a stand-alone body or as part of a local authority department). in extreme situations where a destination is deluged with tourists due to its popularity, the public sector may lead with a public-private sector partnership involving business interests to manage the visitors on the ground • at the country level, it is the national tourism organizations, funded by the public sector through taxes and sometimes with private sector members, who promote and market the country as a place to visit and attempt to manage the diverse interests involved in tourism • at each level, be it the individual business, destination or country, a complex web of interactions and interrelationships exist which need to be taken into account in the decisions, interests and actions taken to manage tourism. in each of these illustrations, the functions of management are harnessed. tourism management as a pursuit, however, is further complicated in that there is a great debate as to what tourism is, what needs to be managed and who should be responsible. the fact that tourism can be seen as an experience based on the pursuit of pleasure and profit raises many complex issues such as whether the tourist is consuming a product, experience or service, and it leads to many debates on what to manage and how far management controls should be exercised by the tourism industry and public sector. so how does this book address these questions? one way is to view the managerial process of tourism as a multilayered process, in which the various organizations and stakeholders involved in tourism engage at different levels through time. figure 1 .11 demonstrates this. the focus begins with the individual business and the management processes (controlling, planning, leading and organizing) are continuous through the interconnected stakeholder groups from the individual business through to the various interests known as the tourism industry. these interests and the connections between management at different levels and between groups mean that, in reality, these groups also have to be aware of external factors that will impact upon management such as the visitor, the business environment, consumer trends, the growth of the leisure society and political processes affecting tourism at government level. the book is organized in such a way that these issues are explained in a manner where the links between different elements of the tourism sector are addressed through examples and case studies. each chapter builds upon the one preceding to develop the knowledge and understanding of what the tourism industry is, the management challenges facing each sector and how tourism affects changes in different contexts. accommodating, anticipating and responding to that level of change is among the major challenges for tourism management in the new millennium. englishmen at rest and play the tourist movement the englishman's holiday the travel trade tourism, principles and practice tourism volumes 1-6: sage library of tourism and hospitality management the consumer society: myths and structures tourism, past present and future the concept of the tourist area cycle of evolution: implications for the evolution of resources (eds) travel, tourism and hospitality research: a handbook for managers and researchers crisis management in the tourism industry the contribution of neil leiper to tourism studies the statistical measurement of tourism tourism systems: an interdisciplinary perspective the nature of managerial work tourism and poverty reduction: pathways to prosperity the experience economy exploring the tourism-poverty nexus tourism and poverty elements of tourism. rome: catal aspects of service dominant logic and its implications for tourism management further reading questions 1 why is tourism such an important activity in the twenty-first century? 2 how would you classify tourists? 3 why is tourism management important for a business operating in the tourism sector? 4 how stable is tourism as an economic activity? key: cord-257749-eyhsc8q8 authors: koul, bhupendra; taak, pooja; kumar, arvind; kumar, anil; sanyal, indraneel title: genus psoralea: a review of the traditional and modern uses, phytochemistry and pharmacology date: 2019-03-25 journal: j ethnopharmacol doi: 10.1016/j.jep.2018.11.036 sha: doc_id: 257749 cord_uid: eyhsc8q8 ethnopharmacological relevance: the genus psoralea (fabaceae) harbours 105 accepted species that are extensively used by local peoples and medicinal practitioners of china, india, and other countries for treatment of tooth decay, psoriasis, leucoderma, leprosy, kidney problems, tuberculosis, indigestion, constipation and impotence. presently, pharmacological research reports are available on only few species namely bituminaria bituminosa (syn: p. bituminosa), p. canescens, p. corylifolia, p. esculenta, p. plicata and p. glandulosa which are valued for their chemical constituents and traditional uses. aim of the review: this review article provides explicit information on traditional uses, phytochemistry, and pharmacological activities of selected psoralea species. the possible trends and perspectives for future research on these plants are also discussed. materials and methods: an extensive and systematic review of the extant literature was carried out, and the data under various sections were identified using a computerized bibliographic search via the pubmed, web of science and google scholar, cab abstracts, medline, embase, inmedplan, natts as well as several websites. key findings: a total of 291 bioactive compounds from 06 species of genus psoralea have been isolated and characterized. however, p. bituminosa alone possess nearly 150 compounds. these bioactive compounds belong to different chemical classes, including flavonoids, coumarins, furanocoumarins, chalcones, quinines, terpenoids and some others due to which these species exhibit significant anti-oxidant, anti-bacterial, anti-fungal, anti-viral, anti-helmintic, anti-diabetic, diuretic, hepatoprotective, anti-cancer and anti-tumor activities. p. corylifolia l. (babchi), a chinese traditional medicinal plant has been used in traditional medicine for many decades for its healing properties against numerous skin diseases such as leprosy, psoriasis and leucoderma. conclusions: the in vitro studies and in vivo models have provided a simple bio-scientific justification for various ethnopharmacological uses of psoralea species. from the toxicological perspective, the root, leaf, and seed extracts and their preparations have been proven to be safe when consumed in the recommended doses. but, meticulous studies on the pharmaceutical standardization, mode of action of the active constituents, and sustainable conservation of psoralea species are needed, to meet the growing demands of the pharmaceutical industries, and to fully exploit their preventive and therapeutic potentials. the medicinal herbs have been a major source of biodynamic compounds of therapeutic value in ayurveda, unani, homeopathy, traditional chinese medicine (tcm) and other traditional system of medicines. several dreadful diseases including cancer, aids, kidney psoralea species have been used in folklore and indigenous system of medicine for a long time. several psoralea products are successfully commercialized and available in the markets (supplemental information 2, table s2 ). the roots of p. argophylla pursh (silver leaf scurf pea, silver leaf indian breadroot) are eaten raw or cooked (tanaka, 1976; yanovsky, 1936) . the dried roots may be ground into a powder and used an ingredient of soups and bread (yanovsky, 1936) . a tea prepared from the leaf and stem powder possess anti-pyretic properties (weiner, 1990) . a decoction of the plant is used as a wash for wounds (moerman, 1998) . the root extract is used as a remedy for chronic constipation (moerman, 1998) . bituminaria bituminosa (l.) c.h.stirt. (arabian pea or pitch trefoil) is used as a forage crop. psoralea canescens michx. (buckroot) roots are eaten raw or cooked (hedrick, 1972; tanaka, 1976; yanovsky, 1936) . the powdered roots are used in preparation of soups or breads (yanovsky, 1936) . as the plant has analgesic properties, a poultice prepared from roots is applied on painful areas of the body (moerman, 1998 ). an infusion of the roots and its steam is used for the treatment of cold, cough, headache and sore throat (moerman, 1998) . psoralea castorea s. watson (beaver indian breadroot) roots are also eaten raw or cooked and the root-powder can be used in soups or breads (hedrick, 1972; tanaka, 1976; uphof, 1968; yanovsky, 1936) . psoralea corylifolia l. (bu gu zhi) is revered in chinese traditional medicine as a tonic to improve general vitality. the name 'buguzhi' (fructus psoraleae) actually comprises of three chinese words: 'bu' means 'to invigorate'; 'gu' means 'bone' and the third word 'zhi' means 'fat'. the chinese name of the herb suggests the function of the herb to provide fat for the invigorating bones. one of the most important features of p. corylifolia is that each and every part of the plant is beneficial which includes roots, stems, leaves, seeds and even blooms (hodges, 2015) . since p. corylifolia is a leprosy destroyer it is revered to as "kushtanashini" in sanskrit. moreove, it is an ancient remedy for leucoderma among the traditional system of medicines in india and china and also among the people in the west (chopra and chopra, 1958 ). in unani system, the plant has been effective against fever, skin diseases and internal ulcers (chopra and chatterjee, 1927) . it is also found to be an effective antihelmintic and sedative (nadkarni, 1976) . for treating leprosy and leucoderma the leaves are consumed as powder and also apllied on skin in the form of paste (anon, 1998; nadkarni, 1976; panda, 2000) . however, some precaution should be taken when applying the herbalpaste externally, since it can cause a skin-allergic reaction when exposed to sunlight (anderson and voorhees, 1980) . the leaves are also used to treat dermatitis, inflammation, mucomembranous disorders, oedematous conditions of the skin and to alleviate diarrhea (rajpal, 2005; sharma et al., 2001; krishnamurthi et al., 1969) . the plant possesses blood purifying properties and therefore used to treat boils, itching eruptions or red papules, ringworm-infection, extensive eczema, rough and discolored dermatosis with fissures, and scabies (khare, 2004) . the essential oil from plant is reported to have a strong effect on streptococcal infection of the skin (rajpal, 2005) . moreover, it is known to improve the color of skin, hair and nails. seeds are sweet, bitter, acrid, and astringent. the seeds are anti-pyretic and also possess alexiteric properties and therefore are given in scorpion-sting or snake bite and in bilious disorders (agharkar, 1991; kapoor and boca, 2001; nadkarni, 1976; panda, 2000) . both the seeds and fruits contain psoralen (furocoumarin), known to regulate pigmentation (rashid and agarwala, 1965; sebastian, 2006) . p. corylifolia seed extracts have been reported to possess anti-hyperglycemic, antidepressant, anti-tumor, anti-bacterial and anti-oxidant property (steven and russell, 2007; wang et al., 1990) . seed extract and powder are beneficial as anti-helmintic, laxative, diuretic, and for healing wounds (rajpal, 2005) . they are used as stomachic, diaphoretic and aphrodisiac . the major components psoralen (92) and isopsoralen (2) are known to possess anti-bacterial, anti-viral and antitumor properties (liu et al., 2004) . therefore, the seeds are used for curing various disorders such as cough, asthma, nephritis, alopecia areata, menstruation, uterine disorders and haemorrhages (qiao et al., 2007; ruan et al., 2007) . the crude extracts of seeds are used in the treatment of febrile diseases, impotence, spermatorrhea, premature ejaculation, lower back pains, incontinence, enuresis, pollakiuria, and cold symptoms in the waist and knees (chopra et al., 1956; lin et al., 2007; zhao et al., 2005a zhao et al., , 2005b . it also possesses coronary vasodilatory activity . the seeds act as deobstruent and heal ulcers, heart troubles, cure blood disorders and elephantiasis (anonymous, 1969; drury, 1873) . the extracts also possess cytotoxic, anti-mutagenic and anti-repellant properties . the seeds are also used to make perfumed oil (gupta et al., 1979; nadkarni, 1976) . in japan, the ethanol extract of the seeds has been used as a preservative for pickles and some processed foods (qiao et al., 2007) . the seed cake is rich in nitrogen and minerals and is used as cattle feed or manure . the fruits of the p. corylifolia also have valuable medicinal uses. the seeds or the seed with the seed pod, possess high aphrodisiac properties allo-aromadendrene (1) u (azzouzi et al., 2014a (azzouzi et al., , 2014b bertoli et al., 2004; innocenti et al., 1998; khatune et al., 2004; pazos-navarro et al., 2011; pistelli et al., 2003; tava et al., 2007) [ reference(s) psoralea canescensmichx. angelicin (isopsoralen) (2) n (innocenti et al., 1997) [ and bhakuni, 2010; wang et al., 2014; won et al., 2015; wu et al., 2007 a, b; wu et al., 2008; xiao et al., 2012; xu et al., 2012; yadava and verma, 2003; yadava and verma, 2005; yang et al., 2006; yang et al., 2009; yin et al., 2004; yu et al., 2005; zhang et al., 2016; zhao et al., 2005a) bakuchicin ( xanthoangelol ( (christensen et al., 2008; kaye and moodie, 1978; perara, reese, 2002; stahnke et al., 2008) [ leaf, flower, seed angelicin (isopsoralen) (2) n (arfaoui et al., 2013; cheikh et al., 2015; el-abgy et al., 2012; hamed et al., 1997 hamed et al., , 1999 khatune et al., 2004; menon et al., 1999; rasool et al., 1989 rasool et al., , 1990 1991; youssef et al., 2013) [ (backhouse et al., 2001; labbe et al., 1996; li et al., 2016; madrid et al., 2012 madrid et al., , 2013 madrid et al., , 2015a madrid et al., , 2015b bakuchiol ( psoralen ( and are used as a tonic to strengthen the genital organs (ven, 1987) . the fruits are bitter in taste, can prevent vomiting, cure difficulty in micturition, cure piles, bronchitis and anaemia and are known to improve complexion (joshi, 2000) . moreover, fruit extract inhibits the growth of mycobacterium tuberculosis (yeung, 1985) . the roots and seeds of p. corylifolia are used for preventing tooth decay (duke, 2009 ). they also promote bone calcification, and hence are beneficial for treating bone fractures and osteoporosis (joshi, 2000; krishnamurthi et al., 1969; rabie, 2010a, 2010b) . psoralea esculenta pursh. (breadroot, large indian breadroot) roots are starchy (70% starch), glutinous (9% protein) with a sweetish turniplike taste (5% sugars) and are eaten raw or cooked (hedrick, 1972; saunders, 2011; tanaka, 1976; uphof, 1968; yanovsky, 1936) . the dried roots are pulverized and used with cereals in making cakes and porridge (facciola, 1983) . a poultice prepared from the crushed roots is applied to sprains and fractures. an infusion of the dried roots is used in the treatment of sore throats, gastro-enteritis and chest problems. the roots are chewed by children as a treatment for bowel complaints (moerman, 1998) . psoralea glandulosa l. is cultivated in chile for its leaves and young shoots, which are used to make a refreshing cold drink. the leaves are anti-helmintic. psoralea hypogaea torr. & a. gray (small indian breadroot) roots are eaten raw or cooked (elias and dykeman, 2009; harrington, 1974; hedrick, 1972; moerman, 1998; yanovsky, 1936) . the roots are rich in starch and can be ground into a powder and used in soups or with cereals for making bread (yanovsky, 1936) . the roots were used an important source of food for the native north american indians (diggs et al., 1999) . psoralea macrostachya dc. (large leather root) roots are eaten raw or cooked and may be dried for winter use. moreover, the plant has been used in the treatment of ulcers and sores (moerman, 1998) . a strong fibre is obtained from the inner bark of the stem (saunders, 2011; usher, 1974) . a fibre is also obtained from the roots, which is used to make ropes and bags (moerman, 1998; uphof, 1968) . roots are aromatic and the perfume persists for several months (saunders, 2011) . a yellow dye is also obtained from the roots (moerman, 1998) . psoralea orbicularis lindl. (roundleaf leather root) leaves are cooked and eaten (moerman, 1998; tanaka, 1976; yanovsky, 1936) . a decoction of the root is used to purify blood and to treat prexia (moerman, 1998) . the plant is a good soil stabilizer (huxley, 1992) . psoralea pedunculata (mill.) vail (sampson's snakeroot) is used as a bitter tonic. psoralea species have been investigated since 1890s (dymock et al., 1893) . leaf, rhizome, root, seeds, fruit and resinous extracts of psoralea species have been subjected to hplc and hptlc followed by pharmacological analyses (pandey et al., 2012; shailajan et al., 2012; uikey et al., 2010; won et al., 2015; yin et al., 2015; zhao et al., 2005a) . detailed and extensive chemical investigation of six psoralea species viz: p. bituminosa l. (syn: bituminaria bituminosa), p. canescens michx., p. corylifolia l., p. esculenta pursh, p. plicata delile and p. glandulosa l. led to the characterization of a large number of bioactive constituents. review of literature reveals the presence of altogether 291 chemical constituents including volatile compounds in the aforementioned species (table 1) . these chemical compounds have been categorized into coumarins, furanocoumarins, flavonoids (polyphenols), isoflavones, meroterpenes, chalcones, phenols, phenolic cinnamates, phenylpropene, sterols, terpenes, tocopherols, benzofurans, sesquiterpenes, acids, fatty acids, alkyl aldehydes, alcohols and esters (agarwal et al., 2006; bertoli et al., 2004; hsu et al., 2001; qiao et al., 2006; ruan et al., 2007; tava et al., 2007; yin et al., 2006 yin et al., , 2007 yu et al., 2005) . the chemical structures of 1-291 compounds are shown in the supplemental information (supplemental information 3, fig. s1 ). their chemical names, chemical class and the corresponding plant sources are compiled in table 1 . the structures of those bioactive compounds which are representative of the genus and with reported pharmacological activities are presented in the main text (fig. 2) . recently, an isoflavone synthase (ifs) gene has been isolated and functionally characterized from p. corylifolia (misra et al., 2010) . the active principle found in p. corylifolia is bakuchiol (155) and psoralen (92) (dev, 1999; wang et al., 2009) . psoralen is linear in structure and may be called as a derivative of umbelliferone (jois et al., 1933; rangari and agrawal, 1992) . the production of psoralen enhances when the plant is exposed low dose of gamma radiation (jan et al., 2011) . isopsoralen (2) is a structural isomer of psoralen (92), and it was found to be identical to angelicin (2) (jois et al., 1933; jois and manjunath, 1934; seshadri and venkata rao, 1937) . angelicin (isopsoralen) (2) is a photosensitizing agent and used for determination of dna and rna structures in cells and microorganisms (kittler et al., 1980) . angelicin (2) and its derivatives occur in a number of plants belonging to the family umbelliferae. the active compound, bakuchiol (155) is a monoterpene phenol, has been obtained in a pure state and named after sanskrit name of the plant (mehta et al., 1973) and possess the potent anti-bacterial property (satyavati et al., 1987) . the seed contains volatile oils, monoterpenes, flavones, coumarins, stigmasteroids, resins, lipid compounds and phenols. the volatile oils include limonene (64), linalool (65), β-caryophyllene (126), geranyl acetate (199) and terpinen-4-ol (97), coumarin derivatives include psoralen (92), isopsoralen (2), isopsoralidin (209), corylidin (179) (211). lipids include triglycerides, diglycerides and monoglycerides. monoterpene phenol includes bakuchiol (155). others include free fatty acids, stigmasterol (232), triacontane (233), daucosterol (192), glucose and saponin. the fatty acids obtained from oil were found to be primarily palmitic acid (86) and linoleic acid (66) together with small fraction of linolenic acid (67). the pharmacologically active oil is identical with the unsaponifiable oil isolated by earlier workers (gaind et al., 1965; gupta et al., 1962) . more that 188 chemical constituents (belonging to furanocoumarins, coumestrol group, chalcones and flavones) have been reported from the seeds chakrovarti et al., 1948; chen et al., 2005; satyavati et al., 1987; tsai et al., 1996) . psoralea species have received tremendous attention because of their bioactive principles possessing remarkable pharmaceutical properties ( fig. 3 ; supplemental information 4, table s3 ). several protocols have been followed to analyse the anti-oxidant property of seeds and leaf extracts of p. bituminosa, p. glandulosa, p. corylifolia, p. plicata, p. esculenta and p. glandulosa. the phenolic compounds obtained from different extracts were found to protect the biological membranes from oxidative stresses (haraguchi et al., 2002; guo et al., 2005; borchardt et al., 2008; kim et al., 2013; madrid et al., 2013; huang et al., 2014) . the antioxidant activity of fruit extracts of psoralea plicata was evaluated by dpph assay. the study indicated that the methanol extract shows an anti-oxidant activity (288.32 micromol trolox equivalent/100 g dry material) which is slightly higher as compare to aqueous extract (258,65μmol trolox equivalent/100 g dry material) (cheikh et al., 2015) . in a study on p. corylifolia, several bioactive compounds such as bakuchiol (155), psoralen (92), isopsoralen (2), corylin (187), corylifolin (185) and psoralidin (228) were screened for their anti-oxidant potential. their antioxidant activities were investigated individually and compared with butylated hydroxytoluene (bht) and α-tocopherol by the oxidative stability instrument (osi) at 100ºc among these compounds psoralidin exhibited highest anti-oxidant activity (5.23) than that of standard compounds (psoralidin > bht > α-tocopherol > bakuchiol > corylifolin > corylin > isopsoralen~psoralen) (jiangning et al., 2005) . however, antioxidant activity alone cannot be of any pharmacological significance. it is accompanied by other specific pharmacological activities to claim any therapeutic benefit. there are several reports on the anti-bacterial activitiy of p. bituminosa and p. corylifolia. the ethanol and methanol extracts obtained from the aerial parts of p. bituminosa contain flavones and isoflavones, while the seed extracts of p. corylifolia contain psoralidin (228), bakuchicin (154), psoralen (92) and angelicin (2), which have shown significant anti-bacterial activities. techniques such as disc-diffusion method, uv (ultraviolet), h nmr (proton nuclear magnetic resonance), c nmr (carbon nuclear magnetic resonance), anti-bacterial assay, broth-dilution method, column chromatography, hplc (high performance liquid chromatography) and tlc (thin layer chromatography) were used to quantitate and analyse the anti-bacterial property of these natural compounds (azzouzi et al., 2014a (azzouzi et al., , 2014b bhawna et al., 2013; cui et al., 2015) . bakuchiol obtained from seed extract of p. corylifolia has been reported to inhibit the growth of staphylococcus mutans and actinomycess viscosus and hence possess strong anti-bacterial activity and mic value of bakuchiol was found to be 9.76-19.5 µg/ml (khushboo et al., 2010; rao et al., 2011) . in a study, the compounds psoralidin (228), bakuchicin (154), psoralen (92) and angelicin (2) obtained from different extracts of the plant were found to show antibacterial activity against different gram-positive and gram-negative bacteria. among them, psoralidin (228) showed highest anti-bacterial activity against shigella sonnei and s. flexneri as depicted by disc diffusion assay . 6.3. anti-fungal activity p. corylifolia and p. glandulosa are known to possess significant antifungal activity. aqueous and methanol extract of seeds and petroleum ether extract of the aerial parts p. corylifolia have been tested against various seed borne fungi such as (alternaria, cladosporium, dreschslera and rhizophus spp.) of maize. in aqueous extract, maximum inhibition (95.4% inhibition at 50% concentration) was observed against a. alternata followed by c. lunata (86.0%), rhizopus sp. (82.3%), d. halodes (68.0%) and c. cladosporioides (57.7%). among the solvents used for the preparation of extracts, maximum inhibition was observed with petroleum ether extract and moderate activity was observed with methanol extract (kiran et al., 2011) . in an anti-fungal assay, the essential oil extracted from p. corylifolia, was studied against three dermatophytic fungi microsporum canis, trichophyton rubrum and trichophyton mentagrophytes. the zone of inhibition (by disc-diffusion assay) for m. canis, t. rubrum and t. mentagrophytes was found to be 20, 35 and 37 mm respectively, while the minimum inhibitory concentration was reported to be 1.4, 0.4 and 0.5 μl/ml, respectively (sharma and tiwari, 2012) . in another study, methanol extract of p. corylifolia seeds was found to be most effective against tomato late blight (phytophthora infestans) and wheat leaf rust (puccinia recondite) (shim et al., 2009) . the crude extract of p. corylifolia exhibited significant antifungal activity against candida albicans . in a study by borate et al. (2014) , methanol extract of p. corylifolia seeds was reported to exhibit a maximum zone of inhibition against c. albicans the crude ethanol extract of the seeds of p. corylifolia exhibited significant anti-viral activity against the severe acute respiratory syndrome corona virus (sars-cov) papain-like protease (plpro). the ic50 value for the same was 15 μg/ml. sars-cov-plpro is the enzyme that is crucial for replication of sars virus . in a recent study, it was reported that bakuchiol (155) present in seeds of p. corylifolia inhibited the influenza a viral infection and growth and activated the nuclear factor erythroid 2-related factor (nrf2) pathway. this pathway is responsible for cellular defense against electrophilic or oxidative stress (shoji et al., 2015) . bakuchiol (155) extracted (petroleum ether extract, dichloromethane extract, and methanol extract) from the aerial parts of p. glandulosa inhibits degranulation in human neutrophils and decreases the cell migration, eicosanoid levels and myeloperoxidase activity in mice thus, confirming its anti-inflammatory potential (ferrándiz et al., 1996; backhouse et al., 2001) . in another study, bakuchiol (155) from p. corylifolia was reported to inhibit the expression of inducible nitric oxide synthase (nos) gene through the inactivation of nuclear transcription factor-b in raw 264.7 macrophages (pae et al., 2001) . the bioactive compounds obtained from leaves, fruits and seeds of p. corylifolia inhibit the functioning of tumor necrosis factor-alpha (tnf-α) and exhibt anti-inflammatory activity (mueller et al., 2010) . the production of inflammatory mediators such as, reactive oxygen species (ros), reactive nitrogen species (rns), and cytokines such as il-1β, il-6 and tnf-α (tumor necrosis factor) in pma (phorbol 12-myristate 13acetate)/lps (lipopolysaccharide), in ifn-stimulated murine peritoneal macrophage cell line (raw 264.7) was inhibited by neobavaisoflavone (212) (szliszka et al., 2011a) . cytotoxicity of neobavaisoflavone (212) was tested by using ldh assay (lactate dehydrogenase assay). psoralidin (228) suppresses the activity of pro-inflammatory cytokines which regulate pulmonary inflammation in human lung-fibroblasts and in mice, by ionizing radiation, has been reported (yang et al., 2011) . in a recent study the activity of il-6-induced stat3 (signal transducer and activator of transcription 3) was found to be inhibited by bavachin (159), bakuchiol, bavachinin (160), corylin (187), corylifol a (180), neobavaisoflavone (212), and isobavachalcone (203). hence, these bioactive compounds hold promise to cure inflammatory diseases . in a study by newton et al. (2002) , forty-three plant species were screened for their anti-mycobacterial activities. among them, bakuchiol (155) extracted from p. corylifolia hexane seed-extract exhibited significant anti-bacterial activity (mic = 31.25 g/ml) against mycobacterium aurum and m. smegmatis thus, confirming its potential for treatment of leprosy. however, these studies further require in vitro and in vivo analyses for their large-scale utilization . in a study by dwarampudi et al. (2012) , the ethanolic seed extract of p. corylifolia showed an ic50 value of 255 μg/ml and a considerable anti-psoriatic activity (75.87%), using the mouse tail model. the seed extract converted parakeratosis stage (keratinization) to orthokeratosis (formation of anuclear keratin layer) stage of the cell, thus confirming its anti-psoriatic potential (dwarampudi et al., 2012) . in a recent report, different micro-emulsions containing single and both commiphora mukul powder and babchi-oil from p. corylifolia were used to assess the anti-psoriatic efficacy on diseased rat paw. the synergistic effect of both the natural products gave better results, hence this herbal combination could be a cheap and effective source of anti-psoriatic agent (marwaha, 2013) . in a study involving human subjects, p. corylifolia hexane-seeds extract was prepared into a cream using stearic acid followed by an open clinical trial on thirty patients suffering from eczema, for a period of one month. the placebo preparation, for this experiment contained all the ingredients except the seed extract. the parameters studied were length of the lesion, exudation rate and rate of itching. the symptoms score reduced after two weeks of cream application. finally, the length of the lesion reduced from 6.367 ± 1.098-0.333 ± .279, exudation rate reduced from 1.333 ± .994-0.165 ± .087 and the rate of itching reduced from 2.567 ± .504-0.165 ± .132. this study concluded that p. corylifolia seed extracts could be used effectively used for the treatment of eczema (gidwani et al., 2010a). the compounds obtained from the p. corylifolia extract have played an influential role for the treatment of vitiligo. the furocoumarins, psoralen (92) and isopsoralen (2) present in psoralea species assists the skin to produce new pigment. they initiate the transformation of dihydroxyphenylalanine (dopa) to melanin when exposed to sunlight and are therefore being used for treating vitiligo, psoriasis and leprosy (fitzpatrick and pathak, 1959; hussain et al., 2016; song et al., 2004; yin et al., 2004) . psoralen (92) alone can effectively treat psoriasis and alopecia areata (ji and xu, 1995; wang and wang, 2007) . in a report by abu tahir et al. (2010), human melanocytes were used to test the antivitiligo activity of the oleo-resinous extracts of the seeds. the seed extract acted as an effective anti-vitiligo agent by restoring the melanocytes of the affected area (abu tahir et al., 2010). ethanol seed extract of p. corylifolia when administrated orally to streptozotocin-nicotinamide (stz) induced diabetic rats lead to an increase in glycogen content of liver and insulin level in plasma with a decrease in plasma cholesterol and blood glucose level (kamboj et al., 2011) . in a report by bera et al. (2013) , the aqueous seed extract of p. corylifolia was found to regulate the functioning of insulin sensitive enzyme activities in wistar strain male albino rats. the seed extract tends to increase the activity of liver hexokinase, glucose-6-phosphate and decrease the level of glucose-6-phosphatase (bera et al., 2013) . the furanocoumarins psoralen (92) and isopsoralen (2) obtained from the seed extract of p. corylifolia have showed anti-depressant activity in mice by hindering the mao (monoamine oxidase) activity, hypothalamic-pituitary-adrenal axis action and oxidative stress . another compound, psoralidin (228) inhibits the transcription of crf (corticotrophin releasing factor) gene, which is responsible for stress response . the anti-depressant activity of psoralidin (228) was evaluated by applying the forced swimming test on rats . psoralen was reported to successfully change the level of 5-hydroxyindoleacetic acid (5-hiaa) and serotonin (5-ht) in hippocampus and frontal cortex of mice . bakuchiol (155) decreases the immobilization time in behavioral despair mouse and plasma epinephrine and norepinephrine (neurotransmitter) levels in bovine adrenal medullary cells hence, exhibits anti-depressant activity . these results depict the anti-depressant activity of psoralen and bakuchiol. psoralea species possess unique bioactive compounds with anticancer properties. p. corylifolia leaves contain remarkably high concentrations (more than 2 g per kg dry weight) of genistein (198), the anti-cancer metabolite. bioactivity of two furocoumarins psoralen (92) and isopsoralen (2) was determined for their cytotoxicity on carcinoma lines kb, kbv200 (vincristine resistance subline of kb), human erythroleukemia cell k562 and k562/adm (doxorubicin resistance subline of k562). both the compounds induced apoptosis in these cells thus, confirming their anti-cancer potential. the ic50 values of psoralen were 88.1, 86.6, 24.4 and 62.6, which of isopsoralen were 61.9, 49.4, 49.6 and 72.0, respectively (wang et al., 2011) . psolaren (92) when subjected to human hepatocarcinoma cells, showed its inhibitory activity by inducing the mechanism of apoptosis. psoralen (92) was able to inhibit the growth of smmc-7721 cells in a dose-and timedependent manner and had a strong proapoptotic effect on these cells (jiang and xiong, 2014; khan et al., 2015) . the bioactive compounds 7,2 ' ,4 ' -trihydroxy-3-arylcoumarin (263), psoracoumestan (224) and corylifol c (182) from p. corylifolia showed strong anti-cancer potential by inhibiting the enzyme mapk/erk kinase phosphorylation and inducing aptotic cell death . in a study, psoralidin (228) showed its activity in mcf-7 cancer cells (isolated from human breast) by induction of ps2 gene activity, with an ec50 value of ere-reporter gene transcription activity of 1.85 μm . the seed extract of p. corylifolia induced apoptosis in the human breast cancer (mcf-7) cells followed by mitochondrial cell death (rajan et al., 2014) . in another study, psoralidin (228) was reported to generate reactive oxygen species and also inhibited a549 cell proliferation. the method adopted was mtt assay and the ic50 values obtained after 24-, 48-and 72-h treatment were 19.2, 15.4, and 11.8 μm, respectively . psoralidin (228) and neobavaisoflavone (212) in combination with trail (tumor necrosis factor-related apoptosis-inducing ligand) have showed their anti-cancer property by inducing apoptosis in lncap (human adinocarcinoma prostate cancer cells) (szliszka et al., 2011a) . in another report, psoralidin (228) in combination with trail influenced apoptosis in hela cells by increasing the expression of death receptor (trail-r2) (bronikowska et al., 2012) . in a similar report, psoralidin (228) compound obtained from different extracts of p. corylifolia exhibited the anti-cancer activitiy against human lung cancer (a549) cells. psoralidin dramatically decreased the cell viabilities in dose and time-dependent manner . psoralea fructus suppressed the proliferation of human colorectal cancer cell lines, such as lovo (ic50: 23.3 ± 1.9 μg/ml), sw480 (ic50: 37.9 ± 1.6 μg/ml), ht-29 (ic50 value: 40.7 ± 1.5 μg/ml), and hct116 (ic50: 45.3 ± 1.2 μg/ml) by decreasing the protein expression of cyclin d1 and cdk4. succeeding experiments with many kinase inhibitors revealed that p. fructus-mediated degradation of cyclin d1 and cdk4 is dependent on gsk3β and/or erk1/2 (park et al., 2016) . psoralen (92), isoporalen (2) and bakuchiol (155) identified in p. corylifolia extracts (chloroform and ethanol) have shown their cytotoxic property against hep-2 cell line (whelan and ryan, 2003) , bgc-823 cancer cell (guo et al., 2003) and cultured human cancer cells (sk-ov-3, a549, xf498 and sk-mel-2hct15) (ryu et al., 1992) . bakuchiol (155) is one of the active ingredients of the dried ripe fruit of p. corylifolia. in a study by miao et al., 2013, bakuchiol (155) suppressed the testosterone induced cell proliferation and gene expression in androgen-dependent prostate cancer (pca) cell line (lncap). the ic50 of bakuchiol (155) to androgen receptor was 8.87 × 10 4 , which was similar to the standard flutamide (10.00 × 10 4 ). bakuchiol (155) has also showed a strong anti-cancer action against human lung adenocarcinoma cell line a549 and showed better results than its analogue resveratrol. ic50 of bakuchiol (155) at 72 h was 9.58 ± 1.12 μmol/l, much lower than that of resveratrol (33.02 ± 2.35 μmol/l). compared to resveratrol, bakuchiol (155) triggered the process of apoptosis to a higher level. it was also observed that oxygen species mediated apoptosis contributes to the cytotoxic properties of bakuchiol (155) and can therefore be used against non-small-cell lung cancer . invitro experiments with a2058 melanoma cells using p. glandulosa resinous exudates revealed that it can inhibit the growth of cancer cells after 48 h of treatment. these experiments confirmed the anti-cancer potential of p. glandulosa which can be attributed to the presence of bakuchiol, 3-hydroxy-bakuchiol and 12-hydroxy-isobakuchiol (madrid et al., 2015b) . ethanol, methanol, chloroform and aqueous seed extracts of p. corylifolia were tested against the tumor cells of mice and were found to stimulate the antibody complement-mediated cytotoxicity during tumor development (latha et al., 2000) . anti-tumor property of bakuchiol (155) was also compared with resveratrol and it was observed that bakuchiol was more efficient in inhibiting the growth of tumor cells, when tested against human lung adeno-carcinoma a549 cell line . in a similar study on tumor cells of murine origin, radioiodinated bakuchiol showed greater cytotoxic effect than bakuchiol (bapat et al., 2005) . bakuchiol (155) also induced erβ expression and suppressed the erα expression in mcf-7 cells (breast cancer cells). it also caused the arrest of s-phase in mcf-7 and mda-mb 231 cells and showed a stronger anti-proliferative effect than resveratrol. additionally, bakuchiol (155) caused the apoptotic cell induction and interrupted membrane potential in mitochondria of mcf-7 cells via an intrinsic apoptotic pathway. the same compound when tested for in vivo anti-breast cancer effect in zebrafish xenografts showed a significant reduction in mcf-7 cell mass (li et al., 2017) . similarly, two more compounds from the same species identified as isobavachalcone (203) and bavachinin (160) attenuate aβ42-induced cell toxicity. the investigation was carried out on yeast two-hybrid system. during this study, eight compounds were tested, and among them ibc (3 μm) and bcn (30 μm) proved to be active at non-toxic concentrations . this is a significant property which is associated with the p. corylifolia fruit extract, the osteoblastic proliferation in cultured umr106 (osteosarcoma) cell line and enhancing the formation of bones . in several studies, p. corylifolia extracts showed significant inhibitory effect on osteoclasts (yang et al., 2007; zhang et al., 1995) . corylin (187) and bavachin/coryfilolin (159) were reported to promote the proliferation of osteoblasts and inhibit bone resorption . bakuchiol (155) compound in the extracts showed inhibitory effect on osteoporosis, mediated through estrogen deficiency (lim et al., 2009; tsai et al., 2007) . in a report by tsai et al. (2007) , it was observed that p. corylifolia extract lead to a decrease in calcium and osteocalcin through urinary excretion in ovariectomized (ovx) rat model and thus, maintained the bone density (tsai et al., 2007) . in a similar report, ethanolic bakuchiol present in seed extract of p. corylifolia reduced the bone loss in ovx rat model thus, showed promising anti-osteoporosis activity (lim et al., 2009 ). the ethanolic fruit extract of p. corylifolia showed estrogenic activity, which was demonstrated by transcription of lacz in recombinant yeast system . in another report by zhao et al. (2007) , proliferation rates of mcf-7 cells increased significantly when treated with the p. corylifolia extract (zhao et al., 2007) . in a study by lim et al. (2011) bakuchiol (155) showed a higher estrogenic activity and estrogen receptor (er) binding affinity than genistein, both in vitro and in vivo (lim et al., 2009 . among the seven bioactive components of p. corylifolia extract exhibited isobavachalcone (203), bavachin (159), corylifol a (180), neobavaisoflavone (212), bakuchiol (155), and two coumarins psoralen (92) and isopsoralen (2) compounds selectively activated er-α while the other compounds activated both er-α and er-β (xin et al., 2010) . park et al. (2012) , reported that bavachin (159) could bind and activate the estrogen receptor . in addition to it, psoralidin (228) was reported as aganist for both er-α and er-β . in a similar study by xin et al. (2010) , seed extract of p. corylifolia containing psoralen (92) and isopsoralen (2) enhanced the mcf7 cell prolification by enhancing the activity of erα (estrogen receptors), hence showed significant estrogenic activity. 6.14. hepatoprotective activity p. corylifolia is revered for its hepatoprotective potential (dai et al., 2009; ye et al., 1999) . three compounds psoralen (92), bakuchicin (153) and bakuchiol (155) (ec50 values of 1.0, 47.0, and 50.0 μg/ml, respectively) have shown hepatoprotective activity towards the liver cells (hep g2 cells) in which the cytotoxicity was induced by tacrine (cholinesterase inhibitor) . in a similar study, bakuchiol (155) reduced the toxic activity of carbon tetrachloride (ccl 4 ), d-galactosamine (d-gain), and tert-butylhydroperoxide (tbh) in primary rat hepatocytes (park et al., 2005) . the activity of hepatic stellate cells (involved in liver fibrosis) was reduced by bakuchiol in liver injured rats thus, confirming its hepatoprotective activity (park et al., 2007) . in a recent report, bakuchiol (155) obtained from the seed extract of the p. corylifolia exhibited hepatoprotective activity by inhibiting the production of reactive oxygen species (ros) and malfunctioning of the mitochondria in human diploid fibroblast (hdf) (seo et al., 2013) . in a study, the cultured rat pheochromocytoma (pc12) cells pretreated with p. corylifolia l. seed extract significantly attenuated 3-np induced cell death, reduced atp levels, and lowered the mitochondrial membrane potential. thus, p. corylifolia seed extract has the potential to treat neurodegenerative diseases (im et al., 2014) . in another study, it was revealed that isobavachalcone, a flavonoid from p. corylifolia, has the ability to ameliorate the neuronal injury in brain diseases related to inflammation, and this was accomplished through inhibition of the expression of lipopolysaccharide induced intercellular adhesion molecule-1 and leukocyte adhesion to brain endothelial cell, by blocking toll-like receptor 4 signaling . 6.16. immunomodulatory activity p. corylifolia extract effectively increased the proliferation rate of diploid fibroblasts (in mice) and increased the ability of non-specific immunity (wang et al., 1990) . in the study, a mixture of fruit extracts of p. corylifolia and brucea javanica improved the immunological regulation in rats that were infected with pneumocystis carinii pneumonia. as a result of the treatment, gain in body weight, decline in the number of cysts produced in the lungs and the level of t cells (cd4 + and cd8 + ) and tnf-alpha in the serum also increased considerably in the immunosuppressed rats (qin et al., 2006) . in another study, the ethanol seed-extracts of p. corylifolia stimulated the immune system in mice by increasing both cell-mediated and humoral immune responses in mice (latha et al., 2000) . 6.17. anti-asthma activity p. corylifolia has long been used for its anti-asthmatic properties. experiments have shown that coumarins isolated from p. corylifolia exhibits anti-asthmatic activity by markedly increasing the level of serum camp (deng et al., 2001; yu et al., 2006) . in another study, a chinese herbal decoction, which contained six herbs, along with p. corylifolia seeds, could prompt treatment for asthma in the convalescent stage, to prevent emphysema (fu, 1989) . in a study by hongfen (2007) , the preparations obtained from the p. corylifolia showed high antiasthma activity by stabilization of mast cells and inhibition of histamine release. thus, the natural compounds obtained from p. corylifolia can act as promising molecules to cure asthma. several studies on animal models showed that a trihydroxyflavone, genistein (198) has the potential to decrease body weight by decreasing the food intake. one such study was conducted on ovariectomised mice wherein, it reduced the fat pad weight and enhanced the apoptosis of adipose tissues. genistein (198) isolated from p. corylifolia, exhibited a potential anti-obesity and ant-diabetic activity through multiple mechanisms and cell signaling pathways by the action on adipocyte life cycle, obesity-related low-grade inflammation, and oxidative stress . in a report, the aqueous and alcohol extracts of the leaves and seeds of p. corylifolia showed significant anti-filarial activity against setaria cervi. alcohol extracts of both leaves and seeds caused death of microfilariae in vitro. the lc50 and lc90 for alcohol extract of leaves and seed was 15, 25 ng/ml and 12, 18 ng/ml respectively (qamaruddin et al., 2002) . the extracts also caused the inhibition of spontaneous movements of the whole worm and the nerve muscle preparation of s. cervi (qamaruddin et al., 2002) . the methanolic p. corylifolia seed extracts was observed to inhibit the aggregation of rabbit platelets induced by arachidonic acid, collagen, and platelet activating factors. the anti-platelet aggregation activity of isobavachalcone was found to be most effective against aggregation induced by arachidonic acid, with a 50% inhibitory concentration (ic50) of about 0.5 µm (tsai et al., 1996) . using rabbit as an animal model, and escherichia coli endotoxin (13 ng/kg) as a pyrogen, the petroleum ether, dichloromethane, and methanol extracts of the aerial parts of p. glandulosa have been reported to possess anti-pyretic activity. the anti-pyretic effect (21.7%) of the petroleum ether extract was reported because of bakuchiol compound present in the extract. maximum anti-pyretic effect (68%) was observed at the dose of 17 mg/kg (backhouse et al., 2001) . isobavachalcone (203) and bavachinin (160) from psoralea modulate amyloid β (aβ) peptides, especially the peptides with 40 (aβ40) or 42 (aβ42) residues, which are believed to be responsible for the development of amyloid plaques in alzheimer's disease. isobavachalcone significantly inhibits both oligomerization and fibrillarization of aβ42, whereas, bavachinin converts aβ42 into large unstructured aggregates in neuroblastoma cells . psoralen (92) isolated from p. corylifolia fruits was investigated as an inhibitor of ache enzyme in an attempt to explore its potential for the management of alzheimer's disease. the concentration of psoralen used was 25-400 μg/ml. it inhibited the ache in a dose-dependent manner in animal models. adult male wistar rats, weighing 180-250 g, were used in the study. while molecular docking study was also carried out, which showed that psoralen (92) binds well within the binding site of the enzyme showing interactions such as hydrogen bonding and π-π stacking . these findings may provide valuable information for the synthesis of new drugs or for the treatment of alzheimer's disease. although having excellent bioactivities, excess intake or use of psoralea is not free from side-effects. p. fascicularis (synonym: psoralea tenuifolia thunb.) has been reported to be toxic to horses, cattle and therefore is not recommended as a fodder. there have been reports on skin allergic reactions after the oral and injected preparations of psoralea (bensky et al., 2004) . in over-dose, psoralea has been associated with dizziness, general weakness, blurred vision, rapid breathing, and vomiting. severe cases of overdose have been associated with vomiting of blood, loss of consciousness, and coma (bensky et al., 2004; chen and chen, 2004) . psoralen plus uva (puva) therapy has been used to treat skin diseases, such as vitiligo and psoriasis. the reported side-effects include dermatitis, blistering, edema, renal complications, loose-motions, biliousness, malaise, sleeplessness, annoyance and mental depression. prolonged therapy has reported to affect liver, eyes, and the immune system (rajpal, 2005) . the psoralen (92) treatment along with uva can cumulatively cause extensive chromosome damage to mammalian cells and could lead to malignancy. a mixture of psoralen (92), isopsoralen (2), and imperatorin caused hypertrophy of liver, kidney, and spleen in rats at a daily dose of 2.5 mg/75 g for 60 days (sharma, 2001) . in a similar study, different concentrations of p. corylifolia extracts were administered to the rats for 90 days. the treatment decreased the body weight and gonad weight (testes and ovaries) thus indicating psoraleninduced reproductive toxicity (takizawa et al., 2002) . there are several reports on hepatotoxicity symptoms in mice and rats after long-term usage of psoralen or isopsoralen (khushboo et al., 2010; totonchy and chiu, 2014; wang et al., 2012) . in an investigation, p. corylifolia and its natural compounds (bavachin, corylifol a, neobavaisoflavone, ibc, and bcn) were evaluated for their potential toxicity, and the results showed it had a potent inhibitory effect against human udp-glucuronosyltransferase 1a1 (ugt1a1) which is considered a stimulant for p. corylifolia related toxicity, including hepatic injury and raised bilirubin levels . in another study, p. corylifolia extract and fractionated compounds such as psoralen (92) and isopsoralen (2) were incubated with the recombinant cyp3a4 enzyme or differentiated huh-7 and heparg cells. p. corylifolia extract, psoralen, and isopsoralen caused the inhibition of concentration cyp3a4 activity in a dose dependent manner with different potency in vitro. it was also noted that none of the sample tested showed any toxicity (liu and flynn, 2015) . three cases of liver injury have been reported in chinese population associated with consumption of p. corylifolia dried seeds (fructus psoraleae) (cheung et al., 2009) . pregnant women are discouraged from consuming p. corylifolia (bensky et al., 2004; chen et al., 2007) . in a case study, a 44-year-old female ingested p. corylifolia seeds every 1 h for seven weeks for treating osteoporosis but, developed acute cholestatic hepatitis (nam et al., 2005) . in another case study, a 64year-old female developed severe hepatotoxicity after administration for nine months of three kinds of herbal tablets and herbal tea for treating vitiligo. tablets made from p. corylifolia leaves were identified as the most probable cause of the hepatotoxicity (teschke and bahre, 2009; teschke et al., 2014) . however, the underlying hepatotoxic mechanisms of p. corylifolia and its major components are not well elucidated. a text on traditional chinese medicine reports that no adverse effects of psoralea occur when a normal dose range (decoction of 4.5-9.0 g) is consumed (bensky et al., 2004) . in all the case-studies/ experiments on psoralea induced toxicity one thing was found common and that is purposeful/deliberate and continuous/prolonged intake/ application of a high dose. going through the available literature we can conclude that there are mixed opinions about the psoralea induced toxicity and therefore there is still a research gap with regard to its mode of action and its pharmaceutical standardization. as already mentioned the genus psoralea has immense potential to cure various diseases and the most important among these are psoriasis, leprosy and vitiligo. although pre-clinical studies have shown promising results, further studies are required to explore the in-depth molecular mechanisms responsible for the afore-mentioned pharmacological activities and to test the efficacy of isolated compounds, in properly designed experiments. in addition, long term toxicity studies and data on interaction with other drugs are also required to establish the safety profile of extracts before the commencement of clinical trials. the efficiency and efficacy of the bioactive compounds present in the psoralea species has been evaluated from time to time. now, since there is awareness complemented with scientific proof regarding the medicinal benefits, their mass cultivation/propagation and extraction of bioactive compounds should also be the objective of further research. the commercialization of pharmaceutical drugs containing psoralea as a sole or a part of the ingredients shall bring relief to millions of people suffering from psoriasis, leprosy and vitiligo, in a natural way. looking into the available literature on the genus psoralea, including the discovery of the number of bioactive compounds from each species (as mentioned in table 1 ) it is very clear that p. corylifolia is an important member of the genus from ethnobotanical, ethnopharmacological, biological, and phytochemical point of view. several bioactive compounds isolated from psoralea are commercially available. the compounds such as daidzin (cas 552-66-9) is a potent inhibitor of human mitochondrial aldehyde dehydrogenase that indicates it chemopreventive property (keung and vallee, 1993) ; angelicin (cas 523-50-2) is an antifungal compound (sardari et al., 2000) ; 8-methoxypsoralen (cas 298-81-7) has been known as a potent suicide inhibitor of cytochrome p-450 (tinel et al., 1987) ; corylifol c and xanthoangelol are potent protein kinase inhibitors and induce apoptotic cell death therefore, possess anti-cancer property ; bakuchiol (cas 10309-37-2) is a ptp1b and dna polymerase inhibitor (choi et al., 2015) ; genistein (cas 446-72-0) is a highly specific inhibitor of protein tyrosine kinase (zarmouh et al., 2016) ; psoralen has been used as photochemical probe in dna mutation and repair studies (gasparro, 1988) ; and bavachin (cas 19879-32-4) stimulates bone formation (anti-osteoporotic activity) xin et al., 2010) . these examples indicate the utility of bioactive compounds isolated from psoralea species. psoralea species are difficult to propagate because of poor seed-germination and high seedling-mortality (mitter et al., 1993; saxena et al., 1997; siva et al., 2014) . to ensure sustained production and benefits of psoralea products we must aim at its mass cultivation through conventional approaches as well as micropropagation (koul and chase, 2015) . psoralea guenzii harv. has become extinct while species like p. asarina (p.j.bergius) t.m.salter, p. fascicularis dc. and p. glaucina harv. are vulnerable to extinction. their bioactive principles and mode of action has not been explored yet. their conservation would also ensure an alternative source of continuous and sustainable supply of elite bioactive compounds such as bakuchiol, psoralen, angelicin and psoralidin, for the pharmaceutical industry (supplemental information 5, table s4 ). although, reproducible or rapid regeneration protocols for all the psoralea species are not yet developed, but the same can ensure the enhancement of bioactive compound(s) production in near future, through suspension culture or transgenic technology (arya and gothalwal, 2015) . these techniques may also streamline the path for further research on the bioactive principles and for the discovery of new compounds with novel properties in future. this is the first report wherein a detailed botanical description, traditional uses, phytochemistry and conservation of psoralea species has been discussed. to conclude, psoralea species have immense potential to act as panacea to several health-related maladies and so its conservation before excessive exploitation should be a prerequisite. current remedies for vitiligo isolation of chalcones from the seeds of psoralea corylifolia linn medicinal plants of bombay presidency psoralea corylifolia l: ethnobotanical, biological, and chemical aspects: a review antipsoriatic microemulsion gel formulations for topical drug delivery of babchi oil (psoralea corylifolia) psoralen photochemotherapy of cutaneous disorders the wealth of india, a dictionary of indian raw materials and industrial products. csir phytopharmacological assessment of medicinal properties of psoralea corylifolia. afr experimental and density functional theory study of a new dimer with tetra-substituted cyclobutane ring system isolated from psoralea plicata seeds phytochemical and biological activities of bituminaria bituminosa l (fabaceae). asian pac anti-oxidant potential of n-buoh extract was evaluated through two methods, dpph and cupric ion reducing anti-oxidant capacity assay. asian pac active constituents isolated from psoralea glandulosa l. with anti-inflammatory and anti-pyretic activities a new chromenochalcone bavachromene from the seeds of psoralea corylifolia preparation and in vitro evaluation of radio iodinated bakuchiol as an anti-tumor agent genistein: a promising therapeutic agent for obesity and diabetes treatment chinese herbal medicine: materia medica protective effect of aqueous extract of seed of psoralea corylifolia (somraji) and seed of trigonella foenum-graecum l (methi) in streptozotocin-induced diabetic rat, comparative evaluation volatile constituents of different organs of psoralea bituminosa l some new flavonoids from psoralea corylifolia antimicrobial activity of psoralea corylifolia linn. 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seeds of psoralea corylifolia l. against seed borne fungi of maize cross-link formation of phage lambda dna in situ photochemically induced by the furocoumarin derivative angelicin determination and comparison of mineral elements in traditional chienese herbal formulae at different decoction times used to improve kidney function -chemometric approach bakuchicin a new simple furanocoumarin from psoralea corylifolia moringa oleifera lam, panacea to several maladies the wealth of india bakuchiol derivatives from the leaves of psoralea glandulosa two antifungal components isolated from fructus psoraleae and folium eucalypti globuli by bioassay--guided purification anti-dermatophytic activity of bakuchiol: in vitro mechanistic studies and in vivo tinea pedis-inhibiting activity in a guinea pig model immunomodulatory and anti-tumour properties of psoralea corylifolia seeds biological effects of the herbal plant-derived phytoestrogen bavachin in primary rat chondrocytes phenolic compounds isolated from psoralea corylifolia inhibits il-6-induced stat3 activation osteoblasts proliferation and differentiation stimulating activities of the main components of fructus psoraleae corylifoliae fructus psoraleae contains natural compounds with potent inhibitory effects towards human carboxylesterase 2 mechanistic study of bakuchiol-induced anti-breast cancer stem cell and in vivo antimetastasis effects ethanol extract of psoralea corylifolia l. and its main constituent bakuchiol reduce bone loss in ovariectomised sprague-dawley rats estrogenic activities of psoralea corylifolia l. seed extracts and main constituents compounds isolated from psoralea corylifolia seeds inhibit protein kinase activity and induce apoptotic cell death in mammalian cells analysis of bakuchiol psoralen and angelicin in crude drugs and commercial concentrated products of fructus psoraleae two new benzofuran derivatives corylifonol and isocorylifonol from the seeds of psoralea corylifolia preparative isolation and purification from psoralea corylifolia by high speed counter current chromatography psoralidin, a coumestan analogue, as a novel potent estrogen receptor signaling molecule isolated from psoralea corylifolia cyp3a4 inhibition by psoralea corylifolia and its major components in human recombinant enzyme differentiated human hepatoma huh-7 and heparg cells phytoestrogen bakuchiol exhibits in vitro and in vivo anti-breast cancer effects by inducing s phase arrest and apoptosis anti-fungal study of the resinous exudates and of meroterpenoids isolated from psoralea glandulosa (fabaceae) study of the chemical composition of the resinous exudate isolated from psoralea glandulosa and evaluation of the antioxidant properties of the terpenoids and the resin antiphytopathogenic activity of psoralea glandulosa (fabaceae) against botrytis cinerea and phytophthora cinnamomi psoralea glandulosa as a potential source of anticancer agents for melanoma treatment extraction modelling and characterization of bioactive components from psoralea corylifolia l. obtained by supercritical carbon dioxide cytotoxic constituents of psoralea corylifolia formulation design and evaluation of herbal anti-psoriatic emulgel bioactive constituents from chinese natural medicines xx inhibitors of antigen-induced degranulation in rbl-2h3 cells from the seeds of psoralea corylifolia meroterpenoids-1 psoralea corylifolia linn-1 bakuchiol a novel monoterpene phenol structure-anti-mutagenic activity relationship study of plicatin b characterization of isoflavone synthase gene from psoralea corylifolia, a medicinal plant overcoming hard seededness on psoralea corylifolia native american ethnobotany a case of acute cholestatic hepatitis associated with the seeds of psoralea corylifolia the evaluation of forty-three plant species for in vitro antimycobacterial activities; isolation of active constituents from psoralea corylifolia and sanguinaria canadensis assessment of antifungal activity of bakuchiol on oral-associated candida spp traditional medicinal knowledge about herb bemchi (psoralea corylifolia) in chhatisgarh herbs cultivation and medicinal uses simultaneous separation and quanti-fication of targeted group of compounds in psoralea corylifolia l. using hplc-pda-ms-ms activation of estrogen receptor by bavachin from psoralea corylifolia anti-cancer activity of psoralea fructus through the downregulation of cyclin d1 and cdk4 in human colorectal cancer cells bakuchiol from psoralea corylifolia inhibits the expression of inducible nitric oxide synthase gene via the inactivation of nuclear transcription factor-κb in raw264.7 macrophages micropropagation from apical and nodal segments of bituminaria bituminosa and the furanocoumarin content of propagated plants neo-psoralen isolated from psoralea corylifolia linn nutritional value of psoralea esculenta pterocarpans from bituminaria morisiana and bituminaria bituminosa meroterpenoids ii psoralea corylifolia linn 2 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plicata a benzoquinone and a coumestan from psoralea plicata lucknow and niscir studies on the chemical constituents of psoralea corylifolia l anti-tumor activity of psoralea corylifolia isolation and identification of furocoumarins from the seeds of psoralea corylifolia l estimation of psoralen content by hplc method in different organs of psoralea corylifolia l. as influenced by sulphur and nitrogen nutrition synthesis and anti-fungal activity of coumarins and angular furanocoumarins antifungal activity of diplotaenia damavandica medicinal plants of india edible and useful wild plants of the united states and canada plant regeneration from callus cultures of psoralea corylifolia linn ayurvedic medicine: the principles of traditional practice, part 2 development of an efficient in vitro regeneration protocol for rapid multiplication and genetic improvement of an important endangered medicinal plant psoralea corylifolia protective role of psoralea corylifolia l. seed extract against 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effect of psoralen cooperated with substrates on tyrosinase activation screening anti-tumor compounds psoralen and isopsoralen from psoralea corylifolia l. seeds. evid. based complement a uplc-ms/ms method for in vivo and in vitro pharmacokinetic studies of psoralenoside isopsoralenoside psoralen and isopsoralen from psoralea corylifolia extract a rapid method for the analysis of ten compounds in psoralea corylifolia l. by uplc earth medicine, earth food ethanolic extracts of euphorbia and other ethnobotanical species as inhibitors of tumor cell growth bioactive metabolites from the fruits of psoralea corylifolia effect of buguzhi (psoralea corylifolia fruit) extract on bone formation systemic effect of fructus psoraleae extract on bone in mice phototherapy in psoriasis. a review of mechanisms of action psoralen and isopsoralen two coumarins of psoraleae fructus can alleviate scopolamine-induced amnesia in rats bisbakuchiols a and b novel dimeric meroterpenoids from psoralea corylifolia hypoxiainducible factor-1 and nuclear factor-κb inhibitory meroterpene analogues of bakuchiol a constituent of the seeds of psoralea corylifolia isolation of a new meroterpene and inhibitors of nitric oxide production from psoralea corylifolia fruits guided by tlc bioautography phytoestrogens from psoralea corylifolia reveal estrogen receptor subtype selectivity simultaneous characterization of prenylated flavonoids and isoflavonoids in psoralea corylifolia l. by liquid chromatography with diode-array detection and quadrupole time-of-flight mass spectrometry anti-depressant-like effects of psoralen isolated from the seeds of psoralea corylifolia in the mouse forced swimming test a new biologically active flavonol glycoside from psoralea corylifolia (linn) effect of psoralea corylifolia l. on the proliferation and differentiation of osteoblast isolated from neonatal rat calvarium in vitro two new compounds from psoralea corylifolia l psc-afp an anti-fungal protein with trypsin inhibitor activity from psoralea corylifolia seeds food plants of the north american indians. united states department of agriculture pharmacokinetics of fructus psoraleae in bile elimination. traditional chinese handbook of chinese herbal formulas anti-depressant-like effects of psoralidin isolated from the seeds of psoralea corylifolia in the forced swimming test in mice quality assessment of psoralea fructus by hplc fingerprint coupled with multi-components analysis psoracorylifols a-e, five novel compounds with activity against helicobacter pylori from seeds of psoralea corylifolia. state key lab anti-bacterial prenylflavone derivatives from psoralea corylifolia, and their structure-activity relationship study cyclobakuchiol c, a new bakuchiol derivative from psoralea coryllfolia experimental and density functional theory study of a new dimer with tetrasubstituted cyclobutane ring system isolated from psoralea plicata seeds chalcones from the seeds of psoralea corylifolia effects of total coumarin on cgmp/cgmp of asthmatic rats evaluation of the isoflavone genistein as reversible human monoamine oxidase-a and-b inhibitor in vitro estrogenic activities of chinese medicinal plants traditionally used for the management of menopausal symptoms the effect of psoralea corylifolia on isolated osteoclasts cells the chemical constituents and bioactivities of psoralea corylifolia linn. a review fingerprint analysis of psoralea corylifolia l.by hplc and lc-ms analysis of psoralea corylifolia l. fruits in different regions evaluation on phytoestrogen effects of ten kinds of chinese medicine including flos carthami the authors are thankful to lovely professional university (lpu), punjab, india for the infrastructural support. the authors are also thankful to the center for chromatography and mass spectrometry, industrial university of santander, columbia for awarding the postkey: cord-007084-4niom5mw authors: popplewell, philip y.; butte, john; azhar, salman title: the influence of age on steroidogenic enzyme activities of the rat adrenal gland: enhanced expression of cholesterol side-chain cleavage activity(*) date: 1987-06-01 journal: endocrinology doi: 10.1210/endo-120-6-2521 sha: doc_id: 7084 cord_uid: 4niom5mw the ability of isolated adrenocortical cells to secrete corticosterone in response to acth challenge declines as rats age, but the site or mechanism(s) of this impairment is still unknown. to test the functionality of steroidogenic capacity per se, we measured the key enzyme activities involved in corticosterone biosynthesis. we also measured the mitochondrial cytochrome p-450 content and nonsteroidogenic enzymes specific for subcellular fractions. mitochondria and microsomal fractions were isolated from the adrenals of 2-, 12-, and 18month-old animals and used for various enzyme measurements. mitochondrial side-chain cleavage enzyme activity (nanomoles per min mg protein(-1)) increased from a mean of 0.43 ± 0.06 in 2-month-old rats to 1.26 ± 0.11 and 1.51 ± 0.06 in 12and 18-month old rats, respectively. after incubation with 5cholesten-3j8,25-diol (25-hydroxycholesterol; 25 μg/ml) sidechain cleave activity rose to 5.0 ± 0.6, 12.4 ± 1.2, and 16 ± 1.4 nmol min(-1) mg protein(-1) in adrenal mitochondrial fractions from 2-, 12-, and 18-month-old rats, respectively. in contrast, mitochondrial cytochrome p-450 content did not vary with advancing age. microsomal δ(5)-3β-hyroxysteroid dehydrogenase-δ(5)-δ(4)isomerase activities were similar in 2and 12-month-old rats, but 21-hydroxylase (nanomoles per min mg protein(-1)) activity was significantly increased in 12-month-old rats (2-month-old, 5.2 ± 0.2; 12-month-old, 7.7 ± 0.5). finally, mitochondrial 11βhydroxylase was comparable in both age groups. in addition, activities of mitochondrial nonsteroidogenic enzymes, such as monoamine oxidase, amytal insensitive nadh cytochrome c reductase, cytochrome c oxidase, succinate dehydrogenase, and malate dehydrogenase, did not change with age. it appears from the evidence presented that the activities of the steroidogenic enzymes are not responsible for the diminished capacity in corticosterone production seen with aging in the rat. (endocrinology120: 2521–2528,1987) i t has been reported previously from this laboratory that the steroidogenic capacity of adrenocortical cells declines as rats age (1) . furthermore, this defect seems to be due to biochemical events distal to binding of acth to its receptor and stimulation of camp production (1) . although the exact mechanism of this defect is yet to be defined, the possibility that this phenomenon may represent a direct effect on the steroidogenic process per se is quite appealing. in rat adrenals, steroid (corticosterone) biosynthesis involves the active participation of cholesterol side-chain cleavage, a 5 -3/?-hydroxysteroid dehydrogenase-a 5 " 4isomerase (3/3-hsd), 21-hydroxylase, and 11/3-hydroxylase activities (2) (3) (4) (5) (6) (7) (8) . among these, cholesterol side-chain cleavage (cytochrome p-450 scc ) catalyzes the first step in corticosterone biosynthesis (i.e. the conversion of cholesterol to pregnenolone) and is generally considered to be the rate-limiting step in steroidogenesis (2) (3) (4) (5) (6) (7) (8) . furthermore, the levels of various steroidogenic enzyme activities have been shown to be influenced and/or regulated by acth (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) . therefore, the age-related decline in corticosterone secretion would be expected to have a profound effect on the activity of some or all steroidogenic enzymes. moreover, this age-related defect may, in fact, result from alterations in the key enzyme(s) involved in corticosterone biosynthesis. the present studies were conducted, therefore, to examine the effects of aging on steroidogenic enzymes responsible for the production of corticosterone. additionally, changes in mitochondrial cytochrome p-450 were compared with the activity of cholesterol side-chain cleavage. finally, to assess nonspecific age-related effects, the activities of several unrelated enzymes associated with specific compartments of mitochondria were also measured. [7-14 c] benzylamine hydrochloride (sa, 50-60 mci/mmol) and [l,2-n3 h]deoxycorticosterone (sa, 35-60 ci/mmol) were obtained from amersham corp. (arlington heights, il). fatty acid-free bsa, glucose-6phosphate, adenine nucleotides, sodium succinate, and cytochrome c were the products of sigma chemical co. (st. louis, mo). all unlabeled steroids were supplied by research plus laboratories (denville, nj). 5-cholesten-3j8,25-diol (25-hydroxycholesterol) was purchased from steraloids, inc. (wilton, ny). all other reagents used were of analytical grade. male retired breeder sprague-dawley rats [crl:cobs cd (sd)br], 9-10 months of age, were obtained from charles rivers breeding laboratories (wilmington, ma) and allowed to age to 12 and 18 months in our facility for aging animals, which is isolated from the general animal quarters in this v.a. center. two-month-old rats of the same strain were obtained from the same source. the rats were housed under conditions of controlled light (constant light from 0600-1800 h each day) and temperature (22-24 c) and given free access to purina laboratory chow (no. 5012, ralston-purina, st. louis, mo) and water. the animals in this colony are routinely monitored for the following viruses and infectious agents: pneumonia virus of mice (pvm), rev-3 virus, encephalomyelitis virus (gd-v11), sendai virus, kilham rat virus, rat corona virus/sialodacryoadenitus (rcv/sda), and mycoplasma pulmonis. occasional animals tested positively for pvm, h-1 virus and rev/sda, but all animals were negative for the remaining agents. routine diagnostic necropsies were not performed. in addition, animals were checked for gross pathology before use. those with visible tumors or apparent defects were discarded. preparation of mitochondria. rats were killed by cervical dislocation, and the adrenals were rapidly removed and trimmed of excess fat and external connective tissue. adrenal mitochondria were isolated by a slightly modified procedure of toaff et al. (16) , as described previously (17, 18) . briefly, adrenals from four to six rats were homogenized in 5 times their wet weight of ice-cold buffer containing 0.25 m sucrose, 1 mm edta, 25 mm hepes (ph 7.0) and 10 mg/ml fatty acid-free bsa (buffer a). the homogenate was then centrifuged at 600 x g (ja 20 rotor, beckman j21, palo alto, ca) for 10 min to remove intact cells, nuclei, and debris. the supernatant was then subjected to centrifugation at 8700 x g for 10 min to sediment mitochondria. the pellet (sedimented mitochondria) was resuspended in buffer a and centrifuged at 600 x g for 10 min, and mitochondria were resedimented at 8700 x g for a further 10 min. the resulting pellet was resuspended in buffer b (0.2 m sucrose, 20 mm kc1,5 mm mgcl 2 , and 25 mm tris-hcl ph 7.4) to a desired protein concentration and immediately used for enzyme measurements. preparation of microsomal fraction. the 8,700 x g supernatant was centrifuged at 15,000 x g for 15 min, and the pellet was discarded. the supernatant fraction was next centrifuged at 105,000 x g for 60 min (60-ti rotor, beckman lm 8 ultracentrifuge) to sediment microsomal fraction. the pellet was washed in buffer a (without bsa) and again collected at 105,000 x g for 60 min. the sediment was resuspended in buffer c (0.25 m sucrose, 1 mm edta, and 10 mm potassium phosphate, ph 7.0) and immediately used for enzyme assays. assay for cholesterol side-chain cleavage activity. the enzyme activity was measured by a slight modification of the procedure of toaff et al. (16) , as described by mori and marsh (17) . the incubation medium in a final volume of 1 ml contained 0.2 m sucrose, 10 mm kc1, 5 mm mgcl 2 , 0.2 mm edta, 10 mm potassium phosphate, 25 mm tris-hcl (ph 7.4), 1 mg/ml bsa (essentially fatty acid free), 3 mm sodium succinate, 6 ftm cyanoketone, and a suitable aliquot of mitochondrial preparation (50-100 ^tg protein/ml) in the presence or absence of 25hydroxycholesterol (25 /ng/ml). after incubation at 37 c for 5-10 min, the reaction was terminated by quick freezing at -60 c. the reaction product, pregnenolone, was extracted from the incubation mixture with hexane (three times, 2 ml each) and assayed by specific ria (19) . cyanoketone was included to inhibit further metabolism of pregnenolone to progesterone. all assays were run in triplicate. the cholesterol side-chain cleavage activity is expressed as nanomoles of pregnenolone formed per min mg protein" 1 . assay for 3/3-hsd. 3/3-hsd activity was determined by measuring the conversion of [ 3 h]pregnenolone to [ 3 h]progesterone as described by shaw et al. (20) . briefly, incubation medium in a final volume of 1.0 ml contained 50 mm potassium phosphate buffer (ph 7.4), 50 nm [ 3 h]pregnenolone (400 dpm/pmol), 0.5 mm nad + , and a suitable aliquot of microsomal fraction. the reaction, maintained at 37 c for 15-30 min, was initiated by the addition of [ 3 h]pregnenolone (dissolved in 30 n\ dimethylsulfoxide). the reaction was stopped by the addition of 0.1 ml 1 n naoh, and unlabeled pregnenolone (50 ng) and progesterone (50 fig) were added in addition to [ 14 c]progesterone (5000 dpm) to monitor recovery. the steroids were extracted two times with 5 ml diethyl ether, and pooled diethyl ether extracts were dried under n 2 . pregnenolone and progesterone were separated by ascending tlc on silica gel h using chloroformdiethyl ether (5:1, vol/vol) as a solvent system. the radioactivity associated with progesterone was measured by liquid scintillation spectrometry (beckman ls3801 scintillation counter). the purity of the [ 3 h]progesterone was determined by repeated recrystallization. all enzyme assays were carried out in triplicate. 3/3-hsd activity is expressed as nanomoles of progesterone produced per min mg protein" 1 . assay for 21-hydroxylase activity. enzyme activity was determined by measuring the formation of [ 14 c]deoxycorticosterone from [ 14 c]progesterone according to the procedure of menard et al. (21) . all incubations were performed at 37 c for 15-20 min. the : incubation medium in a final volume of 0.4 ml contained 50 mm tris-hcl (ph 7.4), 0.6 mm nadph, 10 mm glucose-6-phosphate, 1 u/ml glucose-6-phosphate dehydrogenase, 5 mm mgcl 2 , 1 mm [ 14 c]progesterone (10,000 dpm/nmol in 2.5% propylene glycol), and a suitable aliquot of the micro-somal fraction. the reaction was initiated by the addition of microsomal fraction and stopped by the addition of 0.04 ml 1 n naoh. fifty micrograms each of progesterone and deoxycorticosterone (containing 5000 dpm [ 3 h]deoxycorticosterone to monitor recovery) were added to each tube, and steroids were extracted with dichloromethane. steroids were separated by tlc (silica gel f254 plates) using dichloromethanebutyl alcohol (1:1, vol/vol) as a mobile phase. the radioactivity associated with deoxycorticosterone was measured by liquid scintillation spectrometry, as described above. all assays were carried out in triplicate. the enzyme activity is expressed as nanomoles of deoxycorticosterone formed per min mg protein" 1 . assay for llfi-hydroxylase. the enzyme activity was measured by following the conversion of [ 3 h]deoxycorticosterone to [ 3 h] corticosterone, as described by churchill et al. (22) . briefly, incubation medium in a final volume of 0.5 ml contained 50 mm tris-hcl (ph 7.4), 1 mm mgcl 2 , 1 mm [ 3 h]deoxycorticosterone (20,000 dpm/nmol in 2.5% propylene glycol), 0.25 m sucrose, 4 mm sodium succinate, and a suitable aliquot of mitochondrial preparation. all incubations were carried out at 37 c for 15-20 min. the reaction was initiated by the addition of mitochondrial suspension and terminated by the addition of 0.05 ml 1 n naoh. fifty micrograms each of deoxycorticosterone and corticosterone were added to each tube, and steroids were extracted with dichloromethane. steroid were separated by tlc using silica gel f 254 plates and dichloromethane-butyl alcohol (1:1, vol/vol) as a solvent system. the plates were run three times in same solvent system, and the corticosteronecontaining areas were isolated, eluted, and counted for radioactivity by liquid scintillation spectrometry, as described above. all enzyme assays were carried out in triplicate. the enzyme activity is expressed as nanomoles of corticosterone formed per min mg protein" 1 . measurement of cytochrome p-450. mitochondrial cytochrome p-450 was measured according to the method of omura and sato (23) . the extinction coefficient of 91 cm" 1 mm" 1 was used to calculate the cytochrome p-450 concentration from the absorbancy difference between 450 and 490 nm. miscellaneous enzyme assays. succinate dehydrogenase activity was measured according to the method of pennington (24) . the activity is expressed as nanomoles of 2-(p-iodophenyl)3-(pnitrophenyl)5-phenyltetrazolium reduced per min mg protein" 1 . malate dehydrogenase was assayed by a modification of the procedure of ochoa (25) , as described by vardanis (26) , with activity expressed as nanomoles of nadh oxidized per min mg protein" 1 . the radiochemical procedure of mccaman et al. (27) was used to quantitate monoamine oxidase, with activity expressed as nanomoles of benzaldehyde produced per min mg protein" 1 . amytal-insensitive nadh cytochrome c reductase was measured by a combination of the procedures of sottocasa et al. (28) and privalle et al. (29) . the enzyme activity is expressed as nanomoles of cytochrome c reduced per min mg protein" 1 . cytochrome oxidase activity was measured according to the methods of cooperstein and lazarow (30) , with activity expressed as nanomoles of cytochrome c oxidized per min mg protein" 1 . the protein content of all fractions was measured by the modified procedure of lowry et al. (31) , as described by markwell et al. (32) . statistical analyses. the results are expressed as the mean ± se. the results were analyzed by analysis of variance. the analysis used the general linear models procedures of sas (sas institute, cary, nc) when giving a significant f value; scheffe's posttests were used to determine differences between any two age groups. p < 0.05 was considered statistically significant. cholesterol side-chain cleavage enzyme activity, the rate-limiting enzyme in corticosterone biosynthesis, was measured in adrenal mitochondria isolated from 2-, 12-, and 18-month-old male sprague-dawley rats. all assays were carried out in the presence and absence of 25hydroxycholesterol (25 /ug/ml). the enzyme-catalyzed reaction product, pregnenolone, was quantitated by a specific ria. results presented in figs. 1 and 2 show incubation time-and enzyme concentration-dependent pregnenolone formation by the adrenal mitochondria isolated from 2-and 12-month-old rats. under basal conditions, the rate of pregnenolone formation was low and exhibited a biphasic response (fig. 1, inset) . in contrast, addition of oxygenated sterol (25-hydroxycholesterol) greatly enhanced pregnenolone production, and again this effect was biphasic. furthermore, at each time point studied, mitochondria from senescent rats synthesized 2-3 times more pregnenolone compared to corresponding values from young control groups. similarly, the rate of pregnenolone formation was linear with protein concentration up to 100 /kg/ml in both age groups examined (fig. 2) . like time-course studies, enzyme concentration studies also revealed enhanced steroidogenic capacity of mitochondria from 12-month-old rats, and this effect was potentiated in the presence of 25-hydroxycholesterol. we next examined the side-chain cleavage enzyme activity in mitochondria isolated from rats 2, 12, and 18 months of age, and the results are presented in fig. 3 . under basal conditions (without 25-hydroxycholesterol), cholesterol side-chain cleavage activity (expressed as nanomoles of pregnenolone produced per min mg protein" 1 ) increased (p < 0.001) from a mean (±se) of 0.43 ± 0.06 in 2-month-old rats to 1.26 ± 0.11 and 1.51 ± 0.06 in the 12-and 18-month-old rats, respectively. similarly, mitochondria isolated from 12-and 18-month-old rats showed significantly higher activity in the presence of more polar exogenous substrate (25-hydroxycholesterol) compared to the 2-month-old groups (18-month-old, 16 ± 1.4; 12-month-old, 12.4 ± 1.2; 2-month-old, 5.0 ± 0.6). all of these enzyme assays were carried out under a nearlinear range of time and enzyme protein concentration. thus mitochondria isolated from the 12-or 18-monthold rats exhibited an enhanced capacity to synthesize pregnenolone compared to mitochondria from control groups. moreover, addition of 25-hydroxycholesterol produced a further substantial increase in pregnenolone formation in mitochondria isolated from older animals, and levels were significantly higher than those in mitochondria from control groups. in contrast to progressive changes in side-chain cleavage activity, mitochondrial cytochrome-p450 contents did not change with age (table 1). a comparison of the activities of other steroidogenic enzymes, 3/3-hsd 21-hydroxylase, and 11/miydroxylase, in microsomal and mitochondrial fractions of adrenals from 2-and 12-month-old animals is shown in table 2 . no significant age-related changes were noted for 3/3-hsd (29.8 ± 1.2 nmol min" 1 mg protein" 1 in 2-monthold rats us. 29.5 ± 2.2 nmol min" 1 mg protein" 1 in 12month-old rats; p = ns). similarly, mitochondrial 110hydroxylase activity was comparable in both age groups examined (1.21 ± 0.15 nmol min" 1 mg protein" 1 in 2month-olds us. 1.19 ± 0.09 nmol min" 1 mg protein" 1 in 12-month-olds; p = ns). in contrast microsomal 21hydroxylase activity was slightly but significantly (p < 0.001) increased in 12-month-old rats (7.7 ± 0.5 nmol min" 1 mg protein" 1 ) compared to that in 2-month-old animals (5.2 ± 0.2 nmol min" 1 mg protein" 1 ). mean activities (±se) of monoamine oxidase, amytalinsensitive nadh cytochrome c reductase, succinate dehydrogenase, cytochrome oxidase, and malate dehydrogenase are presented in table 3 . monoamine oxidase (33, 34) and amytal-insensitive results are the mean ± se. the number of experiments is given in parentheses. "expressed as nanomoles of progesterone produced per min mg protein" 1 . 6 expressed as nanomoles of deoxycorticosterone produced per min mg protein" 1 . c expressed as nanomoles of corticosterone produced per min mg protein" 1 . results are the mean ± se of eight separate experiments. 0 expressed as nanomoles of benzaldehyde produced per min mg protein" 1 . 6 expressed as nanomoles of cytochrome c reduced per min mg protein" 1 . c expressed as nanomoles of iodonitrotetrazolium reduced per min mg protein" 1 . d expressed as nanomoles of cytochrome c oxidized per min mg protein" 1 . e expressed as nanomoles of nadh oxidized per min mg protein" 1 . nadh cytochrome c reductase (18, 28, 29, 35) are located on the outer mitochondrial membrane and were chosen for study to serve as a control for the increase in sidechain cleavage activity associated with preparation of mitochondrial fractions. succinate dehydrogenase and cytochrome oxidase are conventional markers of the inner mitochondrial membrane (26) and were chosen as a control for the possibility that age leads to a generalized change in the activity of adrenal enzymes. malate jdehydrogenase is a classical marker for mitochondrial matrix (26, 29) and was employed to serve as a control for mitochondrial integrity. the fact that the activity of none of these enzymes changed as rats grew older provides support for the relative specificity of the age-related increase in cholesterol side-chain cleavage activity. the ability of isolated adrenocortical cells to respond to acth declines with advancing age (1, 36) . we have shown previously that this aging defect lies distal to both binding of acth to its receptor and the consequent production of its secondary messenger camp (1) . in the present studies the possible relationship between steroidogenic enzyme activities and steroidogenesis in rat adrenals during aging was explored. accordingly, we measured cholesterol side-chain cleavage, 3/3-hsd, 21-hydroxylase, 11/3-hydroxylase activities, and cytochrome p450 contents in appropriate mitochondrial and microsomal fractions of adrenals from 2-, 12-, and 18-month-old rats. an unexpected finding was that cholesterol side-chain cleavage activity showed a progressive increase with advancing age. a slight but significant increase in the activity of 21-hydroxylase was also noted in adrenal microsomal fractions from senescent rats. in contrast, activities of 3/3-hsd and 110hydroxylase were insensitive to the aging process. interestingly, the current results have clearly indicated that adrenal side-chain cleavage enzyme activity increased at a time when acth-induced cellular steroidogenesis has been more than 60% depressed (1, 36) . several mechanisms might account for the stimulatory effect of aging on cholesterol side-chain cleavage activity. one possibility is an augmentation of enzyme synthesis. in addition, if degradation of cholesterol side-chain cleavage enzyme protein were to proceed at a lower rate than in young rats, the levels of this enzyme would be expected to be higher, since the steady state level of any given protein is achieved by its relative rates of synthesis and degradation. a second possibility may be that an increased activity represents cellular adaptive changes to deal with the diminished capacity of the adrenal gland to mobilize and use cholesterol esters for steroidogenesis. indeed, we have recently shown that cholesterol ester content increases with age and that this defect was related to specific changes in neutral cholesterol esterase (popplewell, p. y., and s. azhar, submitted). thus, an increase in cholesterol side-chain cleavage activity can be viewed as a compensation on the part of the enzyme to the elevated cholesterol esters levels. that is, mitochondrial side-chain cleavage enzymes increase in activity in order to effectively use that cholesterol which becomes available from the stored cholesterol ester. however, the fact that the adrenal steroidogenic response is still blunted in senescent rats demonstrates this to be a partially successful compensation. another possibility of equal importance is that the observed increase in cholesterol side-chain activity may be in response to vastly elevated levels of plasma acth, previously reported in senescent rats (37) . this hyperstimulation hypothesis is supported by the observations that the cholesterol side-chain cleavage step is the rate-limiting step in steroidogenesis and, as such, activated/regulated by acth (2, 4, 5) . finally, evidence has recently been presented to support the idea that adrenal mitochondria contain more than one cholesterol side-chain cleavage system (38) (39) (40) . thus, it is conceivable that elevated levels represent stimulation of only one isoenzymic form which may or may not actively participate in steroidogenesis under in vivo situations. obviously more rigorous experimental approaches are needed to sort out these various possibilities. such investigations are currently in progress in our laboratory. we were unable to document any age-related changes in mitochondrial cytochrome p450 levels. these results point to a dissociation between cytochrome p450 levels and cholesterol side-chain cleavage enzyme activity. this discrepancy could be attributed to a variation in the relative compositions of various forms of cytochrome p450 in total mitochondrial preparations from young and senescent rat adrenals (41, 42) . in addition, a pool of cytochrome p450 not associated with steroidogenic enzymes (i.e. cytochrome p450 8cc or cytochrome p450 u/ 3) may exist (12) , which, in turn, could mask a real age effect on specific cytochrome p450 8cc . the above hypothesis is of interest in view of the previous finding demonstrating a dissociation in half-lives of 21-hydroxylase and cytochrome p450 (4.5 vs. 2.9 days) in rat adrenals after hypophysectomy (12) . additional evidence for this hypothesis is the recent finding of naumoff and stevenson (43) , who observed a delayed developmental maturation pattern for cholesterol side-chain activity compared to cytochrome p450 in rat ovaries after gonadotropin treatment. in view of these observations, it is not unreasonable to speculate that levels of cytochrome p450 and side-chain cleavage are modulated differentially as rats grow old. finally, demonstration of any specific age effect on cytochrome p450 8cc will require the purification of a side-chain cleavage enzyme system from adrenals of young and old rats. results of the present study also suggest that the decline in steroidogenesis observed in adrenocortical cells isolated from senescent rats is not related to a reduction in cholesterol side-chain cleavage activity or other steroidogenic responses, as measured in vitro in isolated subcellular components. these in vitro results do hot exclude the possibility, however, that side-chain cleavage activity is reduced (or blunted) in intact cells or in vivo. furthermore, the possibility that the aging process directly affects the performance (in vivo) of recently identified regulator (29, (44) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) of the side-chain cleavage enzyme activity should also be considered. previous reports indicate that the aging process in mouse and rat adrenals is associated with changes in 3/3-hsd (55, 56) . we realize that our inability to demonstrate an age effect on this enzyme are in conflict with earlier studies (55, 56) . several technical/physiological differences in the experimental approach to the problem may account for the observed incongruent findings. for instance, the earlier studies were carried out with female rats or mice, as opposed to male rats employed in the present studies. additionally, variations in the assay mixture and other experimental conditions may account for the observed discrepancy. likewise, alterations in nutritional status, animal strain, or other physiological factors could also contribute significantly. finally, since this enzyme is not rate limiting, even a modest decline in its activity should have very little adverse effect on the overall steroidogenic capacity of the adrenal gland. significant changes in some steroidogenic enzymes in other steroid-producing tissues have been demonstrated in senescent rats. for example, testicular 30-hsd activities have been shown to decline with advancing age (57) (58) (59) . similarly, other researchers have reported significant age-related loss of this enzyme activity in rat ovary (60) (61) (62) . likewise, other researchers have presented evidence that activities of 17a-hydroxylase (57, 59, 63) , c17-20 lyase (63), as well as microsomal cytochrome p-450 (63) are depressed in testes from aged rats. however, comparison of data from different steroidogenic tissues suggests that changes in enzyme activities that occur with aging in one steroid-producing tissue may not necessarily be applicable to other steroid-producing tissues. in conclusion, the results of the present study suggest that the impairment of corticosterone secretion in adrenocortical cells isolated from senescent rats is probably not related to a reduction in the activity of steroidogenic enzymes, as measured in vitro. however, since the transport of cholesterol to cytochrome p450 scc rather than the activity of cytochrome p450 scc per se limits the rate of steroidogenesis, it is possible at this time to at least speculate that the age-related decline in steroidogenesis is related to a decrease in the transport of cholesterol to the mitochondria. the roles of microtubules (44), microfilaments (44) , phospholipids (40, (45) (46) (47) 52) , sterol carrier proteins (48) (49) (50) (51) , and other factors (28, 53, 54) have all been described as playing a part in cholesterol transport. failure of or changes in any of these mechanisms with age would reduce the amount of cholesterol substrate available for steroidogenesis within the mitochondria, and we are presently studying the possibility that cholesterol transport is also altered with age. differential effects of aging on acth receptors, adenosine 3',5' cyclic monophosphate response and corticosterone secretion in adrenocortical cells from sprague-dawley rats on the mechanism of action of acth adrenal gland cholesterol side-chain cleavage, cytochrome p450, and the control of steroidogenesis cholesterol metabolism in the adrenal cortex regulation of the adrenal and gonadal microsomal mixed function oxygenases of steroid hormone biosynthesis the roles of cytochrome p450 in the synthesis and metabolism of steroids a heuristic proposal for understanding steroidogenic processes the mechanism of action of adrenocorticotropic hormone: the role of mitochondrial cholesterol accumulation in the regulation of steroidogenesis evidence that the cyclohexamide-sensitive site of adrenocorticotropic hormone action is in the mitochondrion: changes in pregnenolone formation, cholesterol content, and the electron paramagnetic resonance spectra of cytochrome p-450 regulation of cytochrome p-450 supported 11-/3-hydroxylation of deoxycortisol by steroids, oxygen and antioxidants in adrenocortical cell cultures life time of adrenal cytochrome p450 as influenced by acth mechanism of induction of a 5 -3/miydroxysteroid dehydrogenase-isomerase activity in rat adrenocortical cells by corticotropin steroidogenic enzyme activities in cultured human definitive zone adrenocortical cells: comparison with bovine adrenocortical cells and resultant differences in adrenal androgen synthesis in vitro spontaneous and adrenocorticotropin dependent maturation of the steroidogenic pathway of ovine fetal adrenal cells relationship of cholesterol supply to luteal mitochondrial steroid synthesis the site of luteinizing hormoe stimulation of steroidogenesis in mitochondria of the rat corpus luteum oxygen dependence of adrenal cortex cholesterol side chain cleavage': implications in the rate-limiting steps in steroidogenesis radioimm'unoassay of serum and ovarian pregnenolone in immature rats synergistic effect of follicle-stimulating hormone and luteinizing hormone on testicular a 5 -3/3-hydroxysteroid dehydrogenase-isomerase: application of a new method for the separation of testicular compartments spironolactone and cytochrome p-450: impairment of steroid 21-hydroxylation in the adrenal cortex topological studies of the steroid hydroxylase complexes in bovine adrenocortical mitochondria the carbon-monoxide binding pigment of liver microsomes. i. evidence for its homoprotein nature biochemistry of dystrophic muscle: mitochondrial succiniate tetrazolium reductase and adenosine triphosphatase malic dehydrogenase from pig heart protein kinase activity at the inner membrane of mammalian mitochondria microdetermination of monoamine oxidase and 5-hydroxytryptophan decarboxylase activities in nervous tissues an electron-transport system associated with the outer membrane of liver mitochondria: a biochemical and morphological study regulation of intramitochondrial cholesterol transfer to side-chain cleavage cytochrome p-450 in rat adrenal gland a microspectrophotometric method for the determination of cytochrome oxidase protein measurement with the folin phenol reagent a modification of the lowry procedure to simplify protein determination in membrane and lipoprotein samples the submitochondrial localization of monoamine oxidase-enzymatic marker for the outer membrane of rat liver mitochondria utilization of intramitochondrial membrane cholesterol by cytochrome p-450 dependent cholesterol side-chain cleavage reaction in bovine adrenocortical mitochondria: steroidogenic and non-steroidogenic pools of cholesterol in the mitochondrial inner membranes localization of l-lactate dehydrogenase in mitochondria aging of the rat adrenocortical cells: response to acth and cyclic amp in vitro the neuroendocrinology of stress and aging: the glucocorticoid cascade hypothesis cytochrome p-450 of adrenal mitochondria: steroid binding sites of two distinguishable forms of rat adrenal mitochondrial cytochrome p-4508c c evidence suggesting that more than one sterol side chain cleavage system exists in mitochondria from bovine adrenal cortex effects of phospholipid and detergent on the substrate specificity of adrenal cytochrome p-450scc: substrate binding and kinetics of cholesterol side-chain oxidation purification and characterization of mitochondrial cytochrome p-450 associated with cholesterol side-chain cleavage from bovine corpus luteum inhibition of cholesterol side chain cleavage by active site directed antibody to corpus luteum cytochrome p450 the differential development of mitochondrial cytochrome p-450 and the respiratory cytochromes in rat ovary intracellular movement of cholesterol in rat adrenal cells: kinetics and effects of inhibitors on the mechanism whereby acth and cyclic amp increase adrenal polyphosphoinositides: rapid stimulation of the synthesis of phosphatidic acid and derivatives of cdp ~ diacylglycerol phosphoinositide metabolism and hormone action adrenocorticotropic hormone-mediated changes in rat adrenal mitochondrial phospholipids sterol carrier protein 2 : delivery of cholesterol from adrenal lipid droplets to mitochondria for pregnenolone synthesis sterol carrier protein 2 : identification of adrenal sterol carrier protein 2 and site of action for mitochondrial cholesterol utilization intramitochondrial movement of adrenal sterol carrier protein with cholesterol in response to corticotropin scallen tj 1985 phospholipid, sterol carrier protein 2 and adrenal steroidogenesis polyphosphoinositide activation of cholesterol side chain cleavage with purified cytochrome p-4508cc brownie ac i983 cholesterol side-chain cleavage in the rat adrenal cortex: isolation of a cycloheximide-sensitive activator peptide modulation of the kinetics of cholesterol side-chain cleavage by an activator and by an inhibitor isolated from the cytosol of the cortex of bovine . adrenals aging and adrenal a 5 -3-/3-hydroxysteroid dehydrogenase in female mice aging and adrenal a 6 -3/3-hydroxysteroid dehydrogenase in female rats the effect of vasectomy on steroid metabolism by the seminiferous tubules and interstitial tissue of the rat testis: a comparison with the effects of aging effect of age on testis a 6 -3j8-hydroxysteroid dehydrogenase in the rat testicular function and sexual activity in senescent mice ovarian a 5 -3/3-hydroxysteroid dehydrogenase in aging rats aging and ovarian a 5 -3j8 hydroxysteroid dehydrogenase in rats aging and ovarian a 5 -3/3-hydroxysteroid dehydrogenase in the pregnant mouse an analysis of the age-related decline in testicular steroidogenesis in the rat key: cord-270037-tq82srhn authors: kramer, holger b.; nicholson, benjamin; kessler, benedikt m.; altun, mikael title: detection of ubiquitin–proteasome enzymatic activities in cells: application of activity-based probes to inhibitor development() date: 2012-05-19 journal: biochim biophys acta mol cell res doi: 10.1016/j.bbamcr.2012.05.014 sha: doc_id: 270037 cord_uid: tq82srhn background: synthetic probes that mimic natural substrates can enable the detection of enzymatic activities in a cellular environment. one area where such activity-based probes have been applied is the ubiquitin–proteasome pathway, which is emerging as an important therapeutic target. a family of reagents has been developed that specifically label deubiquitylating enzymes (dubs) and facilitate characterization of their inhibitors. scope of review: here we focus on the application of probes for intracellular dubs, a group of specific proteases involved in the ubiquitin proteasome system. in particular, the functional characterization of the active subunits of this family of proteases that specifically recognize ubiquitin and ubiquitin-like proteins will be discussed. in addition we present the potential and design of activity-based probes targeting kinases and phosphatases to study phosphorylation. major conclusions: synthetic molecular probes have increased our understanding of the functional role of dubs in living cells. in addition to the detection of enzymatic activities of known members, activity-based probes have contributed to a number of functional assignments of previously uncharacterized enzymes. this method enables cellular validation of the specificity of small molecule dub inhibitors. general significance: molecular probes combined with mass spectrometry-based proteomics and cellular assays represent a powerful approach for discovery and functional validation, a concept that can be expanded to other enzyme classes. this addresses a need for more informative cell-based assays that are required to accelerate the drug development process. this article is part of a special issue entitled: ubiquitin drug discovery and diagnostics. the last two decades have witnessed the development and application of activity based probes for the detection of enzymatic activities related to a wide range of protein post-translational modifications (ptms). these tools have allowed for the detection of many enzymatic activities in relation to conjugation and deconjugation of ptms. the greatest success and widest application of this approach have probably been found within the ubiquitin proteasome pathway [1] . the ubiquitin proteasome system (ups) consists of three different elements with partially opposing, but complementary roles; the ubiquitin conjugating cascade, the deubiquitylating enzymes and the proteasome complex (fig. 1) . the ubiquitin conjugating cascade of enzymes (e1, e2, e3 and e4) is responsible for conjugating ubiquitin (ub)/ubiquitin-like proteins (ubls) to other proteins as signaling molecules in several biological processes [2, 3] . the deubiquitylating enzymes (dubs) are responsible for removing, trimming or editing the ub/ubl modifications from proteins [2] . the proteasome complex, composed of at least three different proteolytically active subunits β1, β2 and β5, degrades the majority of soluble proteins within the cell following polyubiquitylation [4] . the ups not only enables the targeted destruction of proteins no longer required by the cell, but also enables the selective deactivation of signaling molecules, removal of pathogenic proteins and production of peptides for presentation to the immune system. the entire pathway comprises close to 1000 genes, is vital for many normal cellular functions and is frequently disrupted in cellular pathologies [5, 6] . a likely explanation for the remarkable success of development of activity-based probes in the ups when compared to small molecule probes related to other ptms, is the ability to target cysteine and threonine proteases successfully by covalent inhibition. these represent the major enzymatic activities of dubs and the proteasome respectively. improved recognition of the protein-based ubiquitin and peptide-derived proteasome probes as compared with small molecule based probes may also contribute. the generation of activity based probes for the ubiquitin pathway as important tools to obtain insights into the ubiquitin proteasome system has been reviewed previously [7] [8] [9] [10] . the focus of this review is the application of activity-based probes in the context of inhibitor development and characterization. this process represents a critical step in arriving at a better understanding of fundamental cellular processes and enables the development of novel targeted therapeutic agents. activity-based probes (abps) are defined by their ability to target subsets of a complex proteome based on labeling of specific enzyme classes in a covalent fashion. the incorporation of specific tags for detection and enrichment allows for visualization and further analysis for example by tandem mass spectrometry. the abp approach is highly complementary to mass spectrometry-based proteomics due to the ability to enrich for specifically captured substrates with the aid of an affinity tag. this also distinguishes the method from the use of radiolabeled covalent inhibitors that support detection but not affinity enrichment. a critical parameter is also the choice of reactive group for covalent labeling of the target enzyme at or close to the enzyme active site. depending on the mechanism of enzymatic catalysis different reactive groups can be chosen for covalent capture. the alkylation of nucleophilic residues (cys, ser, thr) present in protease active sites by reactive electrophiles has been a very successful realization of this method. the utility of abps is particularly evident in the study of enzyme systems involved in the attachment and removal of ptms. due to the enzyme active site chemistries involved abp development has been generally more fruitful for the targeting of deconjugating enzymes that usually contain strong nucleophiles at their active sites when compared to the respective ligases/transferases. the discovery and development of proteasome inhibitors have been previously covered by comprehensive reviews [10, 11] . here, we will therefore only give a brief introduction to the proteasome complex and proteasome active site probes. the proteolytically active sites of the proteasome complex are located on distinct subunits (for example β1, β2 and β5 in the constitutive proteasome) and this is reflected by the labeling pattern obtained by active site-directed proteasome probes [12] . the three subunits responsible for proteolysis also correspond to different activity profiles with respect to substrate specificity which were named after prototypic proteases: chymotrypsin-like activity for β5 (ct-l), trypsinlike activity for β2 (t-l) and petidylglutamyl peptide hydrolyzinglike (pgph-l) activity (also referred to as caspase-like) for β1 [13] . exchange of the active subunits with close homologues can be induced in immune cells [14] and the thymus [15] . this allows for the tuning of the peptide repertoire produced by proteasomal proteolysis, which underscores the importance of presentation of these peptides (after further processing steps) in immune surveillance. proteolytically active subunits of the proteasome have been targeted by probes based on peptide scaffolds bearing a c-terminal electrophile (fig. 2) . the most popular designs have been based on the trileucine vinylsulfone (l 3 vs) sub-structure and on functionalized epoxomicin derivatives. profiling with these probes is enabled by detection with dansyl [16] and biotin [17, 18] tags and with strong fluorophores [19, 20] as well as by radiolabels [12, 21] . alternatively, a two step protocol can be applied whereby the tag is attached in a bioorthogonal ligation step following labeling of active proteasome subunits in a cell lysate [22] . this selective ligation is possible through application of the staudinger ligation [23] or 1,4-triazole formation also known as "click" chemistry [24, 25] . a more recent addition to the arsenal of proteasome-directed probes has been the belacostin a derived dansyl-kf33955 probe [26] . this β-lactone containing probe was used successfully in the labeling of β1, β2 and β5 subunits of the 26s proteasome in hela cells as well as the 20s proteasome from erythrocytes. ubiquitin derived abps [27, 28] have been used for the profiling of the active dub population in cell lines, primary cells and tissues [29] . subsequently this concept has been extended to the study of proteases specific for ubiquitin-like proteins (ubls) [30] . a complex proteome such as a cell or tissue lysate is labeled by incubation with ubiquitin probe, followed by sds-page separation and immunoblotting against the epitope tag genetically encoded in the probe construct. thereby a read-out, which is dependent on dub abundance and activity, is obtained. this approach was also extended to the investigation of cancer cell lines [29, 31] and patient biopsies [31] . particularly fruitful was the study of in vitro infection models of viral [32] [33] [34] [35] , parasitic [36, 37] and bacterial [38, 39] pathogens. in this way previously unknown dubs encoded by pathogens were identified and other interactions of pathogen encoded factors with the host ubiquitin proteasome system were elucidated. dub related pathogen-host interactions have been reviewed in detail elsewhere [40] [41] [42] [43] . ubiquitin probes have further enabled structural studies on dub-ubiquitin complexes [44] . in these investigations the crystallization and x-ray diffraction of covalent adducts formed between enzyme and the ubiquitin probe allowed insights into some of the molecular determinants of interactions of dubs with ubiquitylated substrates. these types of studies have also been successfully carried out with complexes involving ubiquitin aldehyde [45] [46] [47] or ubiquitin probes devoid of an epitope tag [48] [49] [50] . in addition to the utility of ubiquitin abps targeting cys protease dubs, ms-based proteomics experiments of ubiquitin probes have also been shown to retrieve other regulators of ubiquitylation, for example metalloprotease dubs were retrieved under native pull-down conditions [51] . this finding might be explained by the formation of non-covalent complexes which can be enriched in immunoprecipitations (ips) under non-denaturing conditions. the targeting and retrieval of ubiquitin ligases by ubiquitin probes have also been observed [52] . usually the reduced nucleophilicity of cys residues in this enzyme class (when compared to cys as part of the catalytic triad in dub proteases) results in strongly reduced capture. this can apparently be compensated for to a certain extend by strong c-terminal electrophiles conjugated to the ub probes [52] . in addition to the above-mentioned applications activity-based proteomics probes have also enabled the development of pharmacologically active enzyme inhibitors. in one format, competition assays between an inhibitor candidate compound and the activitybased probe can be performed in cell lysates. in this type of assay format the competition between the small molecule inhibitor and the probe leads to a reduced labeling profile for the activity-based probe. the loss of signal for labeling of specific target enzymes allows assessment of the specificity of inhibition, while titration of concentration ranges provides a measure of ic 50 values for the respective inhibitor. several features make this type of assay format particularly attractive: the approach represents a cell-based assay in which treatment by the inhibitor candidate can be performed on intact cells. in contrast to the majority of in vitro enzyme assays, a range of active cellular enzymes can be assayed simultaneously. this is only limited by the number of enzymes successfully labeled by the activity-based probe and the representation of active enzymes in the cellular proteome. quantifiable results can be obtained using various readout formats including immunoblotting, in-gel fluorescence detection or ip followed by quantitative msbased proteomics. such an approach has been employed successfully for a number of abps including in the identification and characterization of selective inhibitors of the proteasome [53, 54] , of cysteine proteases in the dub enzyme family [51] and serine hydrolases in the fatty acid amide hydrolase class [55] . promiscuous inhibitors can be tested in this way in order to demonstrate their broad inhibition profile [56] and competition assays can be applied to the characterization of the specificity of known drugs. the development of novel cancer therapeutics is a prime example where the success of bortezomib [16, 57] for treatment of multiple myeloma [58] has provided proof of concept for the value of interventions targeting the ubiquitin proteasome system. the effects of bortezomib (ps-341) on the activity and composition of proteasomes in multiple myeloma cells were investigated by labeling with proteasome probe ada-[ 125 i]-y-ahx 3 l 3 vs demonstrating that the inhibitor selectively targets β5 and β1 subunits (as well as immunoproteasome subunits β5i and β1i) [57] . the corresponding experiments were carried out in the presence or absence of cytokines, which induce the formation of immunoproteasomes under conditions that may be encountered in the bone marrow. a similar characterization of the subunit specificity of proteasome inhibition was also carried out for the orally active inhibitor npi-0052 (salinosporamide a) in multiple myeloma cells [59] . the results of competitive labeling with the proteasome probe dansyl-ahx 3 l 3 vs indicated that the inhibitor targets the β1, β2 and β5 subunits. this result was consistent with the finding that cleavage of fluorogenic substrates showed inhibition of the ct-l, t-l and pgph-l activities of the proteasome. in a comparable study the specificity of the three proteasome inhibitors bzlllcocho, bortezomib (ps-341) and mg132 was assessed by labeling with the cell permeable dansyl-ahx 3 l 3 vs probe following treatment with individual inhibitors for 24 h [60] . this demonstrated clearly distinct labeling pattern of the proteolytically active proteasome subunits β1, β2 and β5 for the three inhibitors. the observed labeling patterns were positively correlated with the inhibition of the ct-l, t-l and pgph-l activities of the proteasome by hydrolysis of suitable fluorogenic substrates in the presence of inhibitors. the selective inhibition of the immunoproteasome subunit β1i (lmp2) by synthetic dihydroeponemycin analogs was demonstrated by competitive labeling experiments in el4 cells using biotinepoxomicin and biotin-eponemycin as a proteasome active site probes [61] . these examples highlight the value of utilizing active site-directed probes in the development and characterization of proteasome inhibitors. this is enabled by their ability to provide a rapid assay of the corresponding proteolytically active subunits in different cell types and in the presence or absence of added competitive inhibitors the specificities of which can thereby be assessed. this approach has been informative to basic science as well as to the development of lead compounds for novel therapeutics. due to the large number of cellular dubs there is a need for innovative assay designs that allow assessment of dub activity in a cellular context. competitive labeling with ub probes provides characterization of lead compounds in a cell culture model thereby providing valuable data for assessment of both compound potency and selectivity of different dubs relevant to a given cell type. a number of dub inhibitors have been characterized and developed into lead compounds for medicinal chemistry programs. generally the initial hit has been obtained by high throughput screening (hts) of compound libraries followed by further optimization using structureactivity relationships. it is noteworthy that many of the identified lead compounds and inhibitors have the ability to covalently label the active site cysteine residue present in the majority of dubs (fig. 3 ). this may occur by conjugate addition, nucleophilic aromatic substitution or disulfide bond formation depending on the chemistry of the small molecule inhibitor. one example of ub probe labeling in the presence of a small molecule inhibitor has been the characterization of wp1130 as a partially selective dub inhibitor which induces aggresome formation and tumor cell apoptosis by kapuria et al. [62] . the selectivity of inhibition for different members of the dub family of enzymes was also investigated by in vitro inhibition assays using ubamc as a substrate in combination with recombinant purified dubs. the total cellular dub activity in lysates treated with inhibitors was tested by ubamc hydrolysis. labeling of treated versus untreated cell lysates with the activity-based probe haubvs was performed in order to assess the dub inhibitory profile of wp1130. in this assay format reduced labeling by the haubvs probe as detected in anti-ha immunoblotting of lysates from cells treated with wp1130 was used as readout of selectivity of dub inhibition. a further focus of this work was the observation of accumulation of polyubiquitylated protein material upon treatment with wp1130 despite a lack of inhibition of proteasome activity. altun et al. described a more extensive application of activitybased probes to the characterization and development of novel dub inhibitors [51] . in this study two dub inhibitors, pr-619 and p22077, were characterized by in vitro enzyme inhibition assays and in cell culture models. labeling of hek293t cell lysates treated with inhibitors at varying concentrations was performed with the ubiquitin probes haubvme and haubbr2 to investigate dub inhibition profiles. as a read-out of these assays immunoblotting against ha-tag or specific dubs of interest was carried out enabling a rapid assessment of inhibitor specificity. in order to obtain an alternative quantitative read-out format, anti-ha immunoprecipitation (ip) was combined with identification and label-free quantification by mass spectrometry based proteomics (fig. 4) . using this approach, quantitative data illustrating the degree of inhibition of 25 cellular dubs was obtained. these data were consistent with the in vitro enzyme characterization data, demonstrating that pr-619 exhibits a broad inhibition profile whereas p22077 is a selective inhibitor of usp7 and usp47. both usp7 and usp47 are considered oncology targets and p22077 and related analogs are the subject of further development as anti-cancer therapeutics [63, 64] . another application of ub probe labeling for the development of usp7 inhibitors was recently demonstrated by reverdy et al. [65] . the screening hit hbx 19,818, which had been identified by high throughput screening (hts) of a compound library employing the ubamc assay, was characterized by haubvs labeling of hct116 cells treated with increasing concentrations of the inhibitor. the readout of the assay was performed by anti-ha immunoblotting and showed reduced probe labeling of usp7 while leaving the competitive labeling of other cellular dubs unaffected. this result was consistent with the in vitro enzyme inhibition data that also indicated a lack of inhibition of other tested cysteine proteases, dubs and ubl specific proteases, but the activity of hbx 19,818 towards the closely related dub usp47 was not discussed. the mechanism of inhibition was investigated by the authors and covalent labeling of the active site cys223 in usp7 was demonstrated, indicating that alkylation of this residue leads to irreversible inactivation of the dub. furthermore the cellular effects of the inhibitor were characterized as reduction in cell proliferation, induction of apoptosis and g1 arrest in a dosedependent fashion. a novel dub inhibitor, b-ap15 was recently described by d'arcy et al. [66] . dub profiling was carried out in the presence of ubiquitin probe haubvs in hct-116 cells after 3 h treatment with 1.0 μm inhibitor; demonstrating that usp14 and to a lesser extend uchl5 were inhibited at this concentration. treatment of cells with b-ap15 led to tumor cell apoptosis, which was independent of tp53 status. additionally an accumulation of high molecular weight ub conjugates and reduced levels of free ubiquitin were observed and ascribed to the inhibition of the 19s associated dubs usp14 and uchl5. the authors concluded that the compound does not act as a broad spectrum dub inhibitor at the concentration employed, rather it inhibits the proteasome associated dubs usp14 and uch-l5. thus, b-ap15 effectively inhibits proteasomal activity by inhibiting the dubs that process polyubiquitylated proteins prior to their engagement by the proteasome. this approach has utility for viral dubs as well. the ubiquitin probe haubvs has been successfully applied to demonstrate the selectivity of inhibitor grl0617 for the sars coronavirus protease and isopeptidase papain-like protease (plpro) in vero e6 cell lysate [67] . no change in labeling profile was observed for cellular dubs at inhibitor concentrations of up to 40 μm. in contrast, the labeling of added plpro was almost completely abolished at the same inhibitor concentration. the usefulness of activity based probes (abps) in the development and characterization of enzyme inhibitors has also been recognized in fields outside the ubiquitin proteasome system. below we describe the advances made in the application of this concept to kinases and phosphatases involved in protein phosphorylation. abps for the targeting of kinases and phosphatases have received considerable attention due to the central role of protein phosphorylation in cellular signaling, protein translocation and ultimately its aberrations in disease. initial kinase probes have utilized atp and adp analogs as molecular scaffolds thereby targeting the essential kinase co-factor in probe design. later approaches were built on modification of known kinase inhibitors of natural product origin or related to licensed drugs. kinase probes based on acyl phosphate atp and adp analogs which lead to the transfer of a biotin to amino acid residues on the interacting protein resulted in the labeling and identification of a range of kinases, atpases, nucleotide biosynthesis-related and other proteins [68] . the lack of selectivity for kinases in a cellular environment is understandable given the wide range of proteins that utilize atp as a cofactor. a tetramethylrhodamine-labeled wortmannin analog ax7503 allowed labeling in mammalian cell lysates and readout of the assay by in gel fluorescence [69] . this fluorescent kinase probe labeled dna dependent protein kinase (dna-pk), phosphoinositide 3 kinase and mammalian polo-like kinase 1 (plk1). previously it had not been appreciated that plk1 is inhibited by wortmannin at relevant concentrations. further wortmannin derivatives labeled with borondipyrromethene (bodipy), tetramethylrhodamine or biotin were prepared successfully [70] . it was shown that the bodipy derivative is cell-permeable thereby enabled labeling of intact cells while the biotin derivative allows isolation of labeled protein material from cell lysates. in a follow-up study to this work liu et al. also demonstrated that polo-like kinase 3 (plk3) is a further molecular target of wortmannin as shown by competitive labeling between ax7503 and wortmannin [71] . the labeling sites of ax7503 for both plk1 and plk3 were determined by tandem mass spectrometry and were found to represent conserved lysine residues in the atp binding site of each of the kinases. a bisindolylmaleimide motif was chosen as the scaffold for the design of a further kinase probe ax4697 [72] . this recognition motif with a high affinity for protein kinase c (pkc) was combined with a chloroacetamide electrophile and a tetramethylrhodamine fluorophore. successful labeling of α and β pkc in jurkat cells was demonstrated as well as loss of signal in staurosporine-pretreated cells. a recent design of a probe for the abelson tyr kinase (abl) was based on the anti-cancer drug imatinib [73] . the reversible mode of enzyme inhibition necessitated the incorporation of a photoreactive benzophenone moiety or a dialdehyde motif for covalent labeling. detection was enabled by the incorporation of a terminal alkyne into the structure allowing attachment of a rhodamine azide dye by cu(i) catalyzed triazole formation (click chemistry) [24, 25] . targeting and detection of abl kinase in the presence of added cell lysate occurred, but the labeling efficiency diminished with increasing amounts of lysate and the approach did not extend to labeling and detection at endogenous levels. the reversible and non-selective kinase inhibitor staurosporine has also been utilized as the recognition motif in probe design by several groups. in these probe designs covalent labeling is enabled by incorporation of photoreactive phenylazide [74] or diazirine [75] groups and irradiation by uv light. enrichment of the trapped proteins is performed by a further incorporated biotin moiety [74] or a terminal alkyne for attachment of either a biotin group or a fluorophore for detection following the covalent capture by click chemistry [75] . activity based probes for protein tyrosine phosphatases (ptps) were developed on several scaffolds that allow mimicry of phosphotyrosine motifs while incorporating reactive electrophiles for the covalent capture of active phosphatases (fig. 5) . several groups exploited the generation of quinone methides for the generation of reactive electrophiles for trapping of ptps [76] [77] [78] [79] . these are generated from substituted phenyl phosphates with benzylic fluoride substituents in ortho or para position. in a recent publication this concept was extended to the design of the unnatural amino acid 2fluoromethyl phosphotyrosine which was incorporated into peptides by solid phase peptide synthesis (spps) [80] . in this way peptidic activity based probes were produced based on known ptp target sequences. in earlier work kumar et al. combined a minimal motif incorporating a bromomethyl phosphonate-substituted phenyl derivative attached to either a fluorophore or biotin for detection [81] . successful labeling of ptps was demonstrated using both isolated enzymes in vitro and in cell lysates of different cancer cell lines. a further alternative approach exploited conjugate addition to substituted aryl vinyl sulfonates and sulfones for the covalent labeling of active ptps [82] . this methodology was then applied to a structural study of a covalent complex between the bacterial ptp yoph and its mechanism based inhibitor. recently a novel probe design was implemented that enables microscopy-based read out through the use of quenched activity based probes [83] . in this strategy the quencher is released upon quinone methide formation and reaction with the target enzyme. the methodology has also been applied to one-and two-photon imaging experiments. in comparison, the targeting of ser/thr phosphatases by activitybased probes has been less frequently realized. a successful example is that of a microcystin derived probe which was prepared and applied to the labeling and isolation of endogenous levels of ser/thr protein phosphatases from jurkat cell lysate [84] . acylphosphate kinase probes based on the atp cofactor [68] were used recently in an extensive study evaluating the specificity profiles of a range of kinase inhibitors [85] . in this 'in situ native kinase profiling' (kinativ) approach, labeling of mammalian cell lysates with the kinase probes was conducted in the presence or absence of the respective inhibitor. the complex samples were then digested with trypsin and biotinylated peptides enriched with streptavidin resin. following elution the captured peptides were analyzed by quantitative proteomics experiments using a targeted lc-ms 2 approach. this detection method significantly improved the signal to noise ratios and allows detection of lower amounts of analyte. quantitative inhibition data for over 200 kinases with six kinase inhibitors was obtained by this method. this approach provides access to quantitative inhibition profiles that are not easily obtained by other experimental approaches and exploits the strengths of both activity-based probe profiling and targeted mass spectrometry-based proteomics. the introduction of activity-based probes into the development of enzyme inhibitors enables the assessment of compound selectivity in a cellular context. this ideally complements more conventional in vitro enzyme assays and allows implementation of this assay format at an early stage in drug development. furthermore competitive labeling experiments have greatly aided the definition of specificities of inhibitors used in cellular research. new therapies in the ups will employ the manipulation of dub activity in a highly selective manner to achieve the desired outcomes. therefore inhibition of selected intracellular dub activities will receive increasing attention as a strategy for pharmacological intervention in disease. dubs with a validated role in oncology are expected to be the first in line for future dub inhibitors. provided that challenges of developing specific inhibitors with desirable compound profiles can be overcome, it is expected that this will enable successful intervention in other pathologies such as inflammatory diseases. activity-based probe designs have provided insights into multiple cellular pathways and have proven extremely valuable as tools for the study of ptm conjugating and deconjugating enzymes. the investigation of the ubiquitin proteasome system has benefited from the development of probes for proteasomal proteolysis as well as deubiquitylating enzymes. specificities and overlapping reactivities of ubiquitin-like proteases were investigated by analogous ubl probes. inhibitor development has been facilitated through competitive labeling assays enabling elucidation of inhibition profiles in a cellular environment. in addition, natural product derived kinase probes have demonstrated the protein targets of these covalent inhibitors, indicating previously unknown molecular targets and providing information in situations where specificities of the respective compounds are not always fully elucidated. the importance of access to selective inhibitors for basic cell biology and drug development makes this area highly suited for successful industry-academia collaborations. the ubiquitin-proteasome pathway: on protein death and cell life mechanism and function of deubiquitinating enzymes the ubiquitin-proteasome proteolytic pathway: destruction for the sake of construction inhibitors of the proteasome block the degradation of most cell proteins and the generation of peptides presented on mhc class i molecules targeting proteins for destruction by the ubiquitin system: implications for human pathobiology protein degradation by the ubiquitinproteasome pathway in normal and disease states chemistry-based functional proteomics: mechanism-based activity-profiling tools for ubiquitin and ubiquitin-like specific proteases putting proteomics on target: activity-based profiling of ubiquitin and ubiquitin-like processing enzymes active-site directed probes to report enzymatic action in the ubiquitin proteasome system chemical tools to study the proteasome proteasome inhibitors: dozens of molecules and still counting substrate binding and sequence preference of the proteasome revealed by active-site-directed affinity probes the active sites of the eukaryotic 20s proteasome and their involvement in subunit precursor processing immunoproteasome assembly: cooperative incorporation of interferon γ (ifn-γ)-inducible subunits regulation of cd8+ t cell development by thymus-specific proteasomes activity probe for in vivo profiling of the specificity of proteasome inhibitor bortezomib total synthesis of the potent proteasome inhibitor epoxomicin: a useful tool for understanding proteasome biology extended peptide-based inhibitors efficiently target the proteasome and reveal overlapping specificities of the catalytic β-subunits profiling proteasome activity in tissue with fluorescent probes a fluorescent broad-spectrum proteasome inhibitor for labeling proteasomes in vitro and in vivo epoxide electrophiles as activity-dependent cysteine protease profiling and discovery tools chemistry in living cells: detection of active proteasomes by a two-step labeling strategy cell surface engineering by a modified staudinger reaction peptidotriazoles on solid phase: [1,2,3]-triazoles by regiospecific copper(i)-catalyzed 1,3-dipolar cycloadditions of terminal alkynes to azides a stepwise huisgen cycloaddition process: copper(i)-catalyzed regioselective "ligation" of azides and terminal alkynes affinity labeling of the proteasome by a belactosin a derived inhibitor chemistry-based functional proteomics reveals novel members of the deubiquitinating enzyme family a novel active site-directed probe specific for deubiquitylating enzymes reveals proteasome association of usp14 activity-based ubiquitin-specific protease (usp), profiling of virus-infected and malignant human cells specific and covalent targeting of conjugating and deconjugating enzymes of ubiquitin-like proteins activity profiling of deubiquitinating enzymes in cervical carcinoma biopsies and cell lines a functional ubiquitin-specific protease embedded in the large tegument protein (orf64) of murine gammaherpesvirus 68 is active during the course of infection a gammaherpesvirus ubiquitin-specific protease is involved in the establishment of murine gammaherpesvirus 68 infection a deubiquitinating enzyme encoded by hsv-1 belongs to a family of cysteine proteases that is conserved across the family herpesviridae high-molecular-weight protein (pul48) of human cytomegalovirus is a competent deubiquitinating protease: mutant viruses altered in its active-site cysteine or histidine are viable artavanis-tsakonas, characterisation of the trichinella spiralis deubiquitinating enzyme, tsuch37, an evolutionarily conserved proteasome interaction partner identification by functional proteomics of a deubiquitinating/deneddylating enzyme in plasmodium falciparum chlamydia trachomatis-derived deubiquitinating enzymes in mammalian cells during infection ubiquitin and ubiquitin-like specific proteases targeted by infectious pathogens: emerging patterns and molecular principles ubiquitination, ubiquitin-like modifiers, and deubiquitination in viral infection bacterial interference of ubiquitination and deubiquitination viral avoidance and exploitation of the ubiquitin system structure of the ubiquitin hydrolase uch-l3 complexed with a suicide substrate crystal 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a tool for enzyme family subclassification, target identification, and inhibitor design discovering potent and selective reversible inhibitors of enzymes in complex proteomes protein cross-linking as a novel mechanism of action of a ubiquitin-activating enzyme inhibitor with anti-tumor activity effects of ps-341 on the activity and composition of proteasomes in multiple myeloma cells a phase 2 study of bortezomib in relapsed, refractory myeloma a novel orally active proteasome inhibitor induces apoptosis in multiple myeloma cells with mechanisms distinct from bortezomib comparative selectivity and specificity of the proteasome inhibitors bzlllcocho, ps-341, and mg-132 lmp2-specific inhibitors: chemical genetic tools for proteasome biology deubiquitinase inhibition by small-molecule wp1130 triggers aggresome formation and tumor cell apoptosis the multifaceted roles of usp7: new therapeutic opportunities usp47 is a deubiquitylating enzyme that regulates base excision repair by controlling steady-state levels of dna polymerase beta discovery of specific inhibitors of human usp7/hausp deubiquitinating enzyme inhibition of proteasome deubiquitinating activity as a new cancer therapy a noncovalent class of papain-like protease/deubiquitinase inhibitors blocks sars virus replication functional interrogation of the kinome using nucleotide acyl phosphates wortmannin, a widely used phosphoinositide 3-kinase inhibitor, also potently inhibits mammalian polo-like kinase a cell-permeable, activity-based probe for protein and lipid kinases polo-like kinases inhibited by wortmannin: labeling site and downstream effects design and synthesis of ax4697, a bisindolylmaleimide exo-affinity probe that labels protein kinase c alpha and beta small molecule probes that target abl kinase comprehensive identification of staurosporine-binding kinases in the hepatocyte cell line hepg2 using capture compound mass spectrometry (ccms) proteome profiling reveals potential cellular targets of staurosporine using a clickable cell-permeable probe study of the preferred modification sites of the quinone methide intermediate resulting from the latent trapping device of the activity probes for hydrolases design and synthesis of class-selective activity probes for protein tyrosine phosphatases activity-based fluorescent probes that target phosphatases activity-based probes for protein tyrosine phosphatases peptide-based activity-based probes (abps) for target-specific profiling of protein tyrosine phosphatases (ptps) global analysis of protein tyrosine phosphatase activity with ultra-sensitive fluorescent probes aryl vinyl sulfonates and sulfones as active site-directed and mechanism-based probes for protein tyrosine phosphatases multicolor, one-and two-photon imaging of enzymatic activities in live cells with fluorescently quenched activity-based probes (qabps) design and synthesis of ax7574: a microcystinderived, fluorescent probe for serine/threonine phosphatases situ kinase profiling reveals functionally relevant properties of native kinases key: cord-007682-01iom9al authors: harrigan, jeanine; jacq, xavier title: monitoring target engagement of deubiquitylating enzymes using activity probes: past, present, and future date: 2016-09-10 journal: proteostasis doi: 10.1007/978-1-4939-3756-1_26 sha: doc_id: 7682 cord_uid: 01iom9al deubiquitylating enzymes or dubs are a class of enzymes that selectively remove the polypeptide posttranslational modification ubiquitin from a number of substrates. approximately 100 dubs exist in human cells and are involved in key regulatory cellular processes, which drive many disease states, making them attractive therapeutic targets. several aspects of dub biology have been studied through genetic knock-out or knock-down, genomic, or proteomic studies. however, investigation of enzyme activation and regulation requires additional tools to monitor cellular and physiological dynamics. a comparison between genetic ablation and dominant-negative target validation with pharmacological inhibition often leads to striking discrepancies. activity probes have been used to profile classes of enzymes, including dubs, and allow functional and dynamic properties to be assigned to individual proteins. the ability to directly monitor dub activity within a native biological system is essential for understanding the physiological and pathological role of individual dubs. we will discuss the evolution of dub activity probes, from in vitro assay development to their use in monitoring dub activity in cells and in animal tissues, as well as recent progress and prospects for assessing dub inhibition in vivo. otherwise distinct. the ubiquitin-proteasome system has multiple essential biological roles, and thus its function and dysfunction, are important factors in various human diseases, including cancer, infection, infl ammation , and neurodegeneration [ 1 -4 ] . ubiquitylation of substrate proteins fi rst involves an atpdependant activation of the ubiquitin polypeptide by the activating enzyme e1 . activation involves covalent linkage between the carboxy terminus of ubiquitin and a cysteine residue present on the e1, forming a thioester bond. the activated ubiquitin is then transferred to an e2 ubiquitin-conjugating enzyme forming a thioester linkage. in the fi nal step, an e3 ligase transfers the ubiquitin from the e2 to the substrate protein. the majority of e3 ligases are classifi ed as ring fi nger e3s and act by bringing the substrate and e2 enzyme in close proximity. the ring fi nger e3s directly transfer ubiquitin from the e2 to the substrate. the hect domain e3s act by forming an intermediate thioester linkage with ubiquitin before transfer to the substrate (reviewed in [ 5 ] ). more recently, a third class of e3 ligases with an intermediate mechanism of action has been identifi ed. the ring-in-between-ring (rbr) e3s are an unusual family of ubiquitin e3-ligases composed of a dozen proteins. their activities are autoinhibited, causing a requirement for activation by protein-protein interactions or posttranslational modifi cations . they catalyze ubiquitin conjugation by a concerted ring/hect-like mechanism in which the ring1 domain facilitates e2-discharge to directly form a thioester intermediate with a cysteine in ring2. this short-lived, hect-like intermediate then modifi es the target [ 6 , 7 ] . following monoubiquitylation of a substrate, the process can either stop, forming monoadducts of ubiquitin, or be repeated forming an elongated chain of ubiquitin residues. polyubiquitin chains can be formed using the n-terminus (linear) or any of the seven internal lysine residues found in ubiquitin, and these various chain topologies lead to different functional outcomes. of the most well studied linkages, k63-linked polyubiquitin chains are often involved in nonproteolytic signal transduction while k48linked chains generally target substrates for proteasomal degradation. a number of additional linkages such as met1, k6, k11, k27, k29, and k33 have been identifi ed and their nondegradative cellular signaling roles are still subject to a number of investigations. the complexity of ubiquitin chain signaling is further enhanced by the existence of mixed-lineage chains [ 8 , 9 ] . proteins destined for degradation via the ubiquitin-proteasome system include proteins that are damaged, improperly folded, or that have short half-lives [ 10 ] . proteins that have been appropriately polyubiquitylated are recognized and degraded by the 26s macromolecular proteasome complex [ 11 ] . the 26s complex consists of a 20s catalytic core particle that is capped at both ends by 19s regulatory particles . the 19s regulatory particle can be further subdivided into lid and base components. following recruitment to the proteasome, polyubiquitylated proteins undergo deubiquitylation and unfolding. the removal of ubiquitin is accomplished by deubiquitylating enzymes (dubs) associated with the 19s lid. ubiquitin polypeptides that are removed from substrate proteins can be directly recycled by the cell. the 19s base component plays a key role in the unfolding of the substrate protein and delivery of the deubiquitylated, unfolded protein into the 20s catalytic core particle. the 20s consists of four layers of ring-like structures [ 12 ] . the outer rings are composed of seven α subunits with the inner rings composed of seven β subunits. the β1 subunits exhibit caspase-like activity, the β2 subunits trypsin-like activity, and β5 subunits chymotrypsin-like activity, collectively degrading proteins into short oligopeptides as well as recycling amino acids [ 5 , 13 ] . ubiquitin is covalently linked to many cellular proteins and regulates their activity, stability, localization, or interactions. ubiquitylation is a reversible process carried out by the opposing activities of ubiquitin ligases and dubs. the human genome encodes approximately 100 dubs [ 14 -16 ] . of the fi ve families of dubs, four ( uch , usp, mjd , and otu ) belong to the cysteine peptidase class, while one (jamm) belongs to the metallopeptidase class. as dubs have been shown to play critical roles in many pathological processes, particularly cancer, infectious disease, and neurodegeneration, they have begun to attract signifi cant attention from the pharmaceutical industry [ 17 -20 ] . unlike most posttranslational modifi cations , ubiquitin is able to form polymeric chains [ 21 ] : the ubiquitin linkage in the chain as well as the length of the chain will impact on the fate of the protein modifi ed by the polymer of ubiquitin [ 9 , 22 ] . pharmacological modulation of dubs using a multitude of approaches in the last decade has seen limited success to date; however, recent progress is beginning to identify dub inhibitors with the potential for drug development [ 23 -27 ] . a number of conceptual and technological obstacles need to be overcome in order to progress genuine dub therapies. a major challenge in characterization of dub inhibitors is the development of high throughput assays monitoring "on-target" inhibition in cells and in vivo. monitoring dub target engagement by small molecule inhibitors in vivo has a number of implications. firstly, as a biomarker readout of inhibition and for understanding the physiological implication of inhibiting a class of enzymes for which there is usually no known unique ubiquitylated substrate. secondly, for assessment of the selectivity of compounds as well as understanding the mechanism of action of the inhibition, including duration, reversibility, and pharmacodynamic parameters. activity-based probes (abps) rely on the design of chemical warheads which selectively react with the active site of an enzyme. abps are usually composed of a reactive electrophile, to covalently modify an active-site residue, and a reporter group to allow detection of the labeled enzyme [ 28 ] , see fig. 1a , b . activity probes have been designed for a number of enzyme classes such as serine hydrolases [ 29 ] , metalloproteases [ 30 , 31 ] , proteasomes [ 32 ] , and oxidoreductases [ 33 ] . epitope-tagged ubiquitin and ubiquitin-like derivatives have been utilized in a variety of assays to identify or monitor active dubs in biological samples [ 34 , 35 ] (fig. 1c ) . ubiquitin abps have been instrumental in the identifi cation of a number of new dubs [ 36 ] including a novel class of dubs: otus [ 37 ] . unlike other proteolytic enzymes, for optimal recognition, dubs require not only an electrophilic trap but also a very large portion of ubiquitin or chains of ubiquitin for binding and recognition in the enzyme active site: truncated portions of ubiquitin are usually not suffi cient to trap dubs. in addition, the isopeptide nature of the covalent linkage of ubiquitin to the target protein monitoring the activity of endogenous enzymes such as dubs in their native, full-length status as well as under all possible naturally occurring posttranslational modifi cations or interference/allosteric regulation from binding partners is a major advantage of abps . the irreversible covalent nature of abps toward their enzyme targets has a number of advantages when compared to many other analytical technologies that rely on weak, naturally transient and diffi cult to capture interactions between an enzyme and its substrate. various warheads (fig. 2 ) have been employed including alkyl halides (chloroethyl, bromoethyl, bromopropyl), michael acceptors ( vinyl methyl ester (vme) , vinyl methyl sulfone (vms) , vinyl phenyl sulfone, vinyl cyanide) and more recently propargyl (pa) [ 36 , 38 , 39 ] . the fi rst attempt at generating activity probes to label dubs on their catalytic site thiol group was described by hidde ploegh and colleagues [ 35 ] . using a trypsin catalyzed transpeptidation to modify ubiquitin at its carboxy terminus with a vinyl sulfone group, they were able to demonstrate that ubiquitin vinyl sulfone labeled not only recombinant purifi ed dubs but also a number of yeast dubs in a crude lysate. the identity of each labeled band was verifi ed using individual yeast dub mutant strains. the initial version of the ubiquitin vinyl sulfone probe was labeled with iodine 125 and allowed for detection of a number of dubs in mouse tissues as well as in mouse cell lysates. in the same study, borodovsky et al. described the use of unlabeled ubiquitin vinyl sulfone to detect a specifi c dub by monitoring a shift in the apparent molecular weight in sds-page followed by immunoblotting: usp7 was labeled effi ciently in mammalian cell lysates. finally, the authors were also able to identify usp14 as a novel dub associated with the proteasome thanks to the use of ubiquitin vinyl sulfone in fractionation and immune-purifi cation assays. in a second generation of activity probes, the thiol-reactive group was added to ubiquitin using an intein-based chemical ligation method [ 36 ] . the reactivity of the dubs depends on the type of electrophilic warhead fused to ubiquitin. the second generation of probes were additionally used for the identifi cation of bound dubs by affi nity purifi cation/ mass spectrometry [ 34 ] . more recently, abps using a fl uorescent reporter tag have been generated to replace the initial tags (e.g., ha) to allow replacement of the immunoblot procedure with fl uorescent imaging [ 39 -41 ] . while the historical production of ubiquitin abps was based on a trypsin catalyzed transpeptidation to modify ubiquitin at its carboxy terminus with a vinyl sulfone group or based on the addition of the electrophilic warhead via intein-based chemical ligation methods, recent approaches have moved toward the full-chemical synthesis of ubiquitin abps [ 41 , 42 ] . this latest improvement has the added advantage of allowing the incorporation of modifi ed amino acid residues at any position in the abps, whether natural or not. in addition their major role in monitoring or identifying active dubs in biological samples, ubiquitin-based probes are useful tools for structural analysis of dubs . a number of cocrystals of dubs with ubiquitin have been solved [ 34 , 39 ] and in some cases, the structure of the apo-dub was not achieved in the absence of the modifi ed ubiquitin abp [ 43 ] . abps are sometimes the only option available for cocrystallizing dubs with ubiquitin substrates or ubiquitin chains . a limited number of studies have demonstrated the utility of activity probes for monitoring dub activity in normal or diseased animal tissues . in earlier dub activity probe publications, mouse tissues were examined and signifi cant differences in the profi le of active dubs in tissues was observed [ 35 ] . more recently, in a very detailed study, altun et al. investigated the activity of dubs in models of aging and dietary restriction [ 44 ] . dramatic differences in the levels of active dubs in cell lines derived from various tissues as well as in primary tissues has been observed [ 45 ] . for a small number of dubs , the activity as monitored by activity probe binding can be correlated with the malignant status of the cell line or tissue, suggesting a possible therapeutic window for dub inhibitors [ 45 ] . given the sensitivity and signifi cance of such techniques, we can expect an increase in the number of studies taking full advantage of ubiquitin abps to monitor differential dub activity in pathological versus normal conditions in the near future. abps have been used to identify and monitor the activity of bacterial, viral, or parasitic dubs including herpes viridae , chlamydia trachomatis , toxoplasma gondii , and plasmodium falciparum : abps are invaluable tools to identify functionally active dubs in complex in sometimes relatively poor or diffi cult to annotate organisms [ 46 -50 ] . while viruses or bacteria do not encode a full complement of ubiquitin proteasome enzyme systems, they express dubs to evade the detection of their proteins by the immune system or otherwise enhance virulence [ 51 ] . in addition, since dubs are essential for viral proliferation, viral dubs have been considered as possible therapeutic strategies for the treatment of certain viral infections such as sars or mers [ 52 ] . mass spectrometry has emerged as an important tool for characterizing the various forms of ubiquitin. initial global characterization of the ubiquitin-modifi ed proteome has been made possible in proteomic studies taking advantage of a monoclonal antibody that recognizes (di-gly)-containing isopeptides following trypsin digestion of complex cellular lysates [ 53 , 54 ] . in the ubiquitin-aqua approach, synthetic isotopically labeled internal standard peptides are used to quantify branched peptides and the branched -gg signature peptides generated by trypsin digestion of ubiquitin signals [ 55 ] . proteomic studies looking at dub interaction partners have also generated a great deal of information about their substrates, regulation, and function [ 56 ] . additional studies have evaluated the functional role of dubs using rnai libraries [ 57 , 58 ] or gfp-dub fusions [ 59 , 60 ] , and have linked dubs to specifi c cellular pathways. while such studies are very informative and have generated a wealth of data on the biological roles of dubs, they provide only limited information regarding the dynamic activity profi le of dubs, and are not able to distinguish the catalytic state (active versus inactive) of dubs. as the cellular activity of dubs can be controlled by multiple factors including protein interactions [ 61 ] , stoichiometric changes to the structure of the protein [ 62 , 63 ] , and posttranslational modifi cations [ 64 , 65 ] , the advantage of activity probes is their specifi c reactivity with catalytically active dubs . one of the benefi ts of abps for the characterization of dub inhibitors is the ability to monitor compound selectivity. a chemical activity-based proteomic approach using ha-tagged ubiquitin labeled with electrophilic warheads (ha-ubbr2 or ha-ub-vme) was undertaken to characterize the selectivity of two usp7 inhibitors either in immunoblots or by quantitative mass spectrometry following treatment of cells or cell lysates with compounds [ 66 ] . an independent study using another usp7 inhibitor displaying selectivity in a panel of biochemical dub assays, was also subjected to cellular selectivity profi ling using ha-ub-vms followed by immunoblotting [ 24 ] . in a more targeted approach, an active-site ubiquitin probe (ha-ub-vms) has been used to demonstrate that usp14/uchl5 inhibition by a small molecule (b-ap15) inhibits the 19s proteasome in a reconstituted biochemical assay. a similar probe approach was also used to demonstrate that b-ap15 is not a general inhibitor of dubs in a cell lysate probed with an anti-ha antibody detecting the conjugated ubiquitin species [ 67 ] . while the studies mentioned above are paving the way for elucidating dub selectivity profi les in a cellular context, coverage of the " dubome " is still limited. technological improvements are still required to increase sensitivity and accurately monitor dubs in a given cell or tissue experiment. while dub proteomic studies using activity probes have mainly been used for monitoring the selectivity of fi rst generation dub inhibitors , the potential for ubiquitin abps is much broader. indeed, it is possible to determine the dynamic nature of dub inhibitors by using abps to monitor the reversibility or the duration of dub inhibition. furthermore, most of the work so far on dubs using abps has been restricted to cellular studies. recent progress in developing dub inhibitors with in vivo preclinical potential is currently driving the tools for pharmacodynamic as well as mode-of-action understanding of dub inhibitors in vivo. activity probes based on selective inhibitors of peptidases have already been developed such as probes targeting proteasomes [ 68 ] , cathepsins [ 69 ] or caspases [ 70 ] and are proving their usefulness for in vivo imaging studies as well as for diagnostic purposes [ 71 ] . the utility of ubiquitin activity probes to identify and characterize dubs in a number of conditions is not limited to ubiquitin. indeed, probes for enzymes that remove ubls have been generated. the exquisite selectivity of dubs for their cognate substrates suggested that specifi c probes are also required for ubl peptidases. an initial approach based on the synthesis of peptide vinyl sulfones harboring various portions of the ubiquitin-like carboxy terminus has suggested that truncated ubls are able to bind ubl-specifi c proteases in a manner similar to the ubiquitin-based vinyl sulfone polypeptides [ 72 ] . ubl-based probes for nedd8 , sumo-1, isg15, gate-16, map1-lc3, gabarap, and apg8l have been successfully synthesized [ 73 -75 ] . an alternative to classical activity probes containing a full ubiquitin or ubiquitin-like polypeptide is based on the use of small molecule inhibitors to label the catalytic site of desumoylating enzymes (sentrin-specifi c proteases, senps ). a peptide acyloxymethyl ketone (aomk) containing a large aromatic o-acyl group are selective covalent inhibitors of senps and can be modifi ed using fl uorescent labels to detect senps activity in biological samples [ 76 ] . a similar approach has been described using a different family of proteins: glycine fl uoromethylketones, which serve as probes to selectively target senps [ 77 ] . a more conventional derivatization of the carboxy-terminal end of ubls with electrophilic warheads has also been pursued and a general derivatization procedure to produce any ubl domain chemically activated at its c-terminus by formation of a thiol ester. reaction of the thiol with a nucleophile produces the desired derivatives taking advantage of the intein fusion technology [ 78 ] . there is no technical challenges preventing the development of fully synthetic ubl abps and indeed, a number of such reagents are already commercially available from various sources. as the mechanism for the removal of ubls by specifi c enzymes has not yet been fully characterized, abps will certainly play a key role in the elucidation of such understanding. similarly, the biological or mechanistic functions of a number of dubs or senps remains poorly understood, and existing abps or novel more selective abps can serve as tools for extending our knowledge. in parallel with the development of monoubiquitin abps , a number of groups have also achieved total (semi)-synthesis of di-ubiquitin [ 42 , 79 -81 ] or even tetra-ubiquitin chains [ 82 , 83 ] . however, incorporation of electrophilic warheads into polyubiquitin chains remains problematic. an intermediate approach to the generation of polyubiquitin abps was elaborated on the basis of the synthesis of branched-peptides incorporating an isopeptide-linked ubiquitin and an electrophilic warhead [ 84 ] . in addition, the synthesis and characterization of k48or k63-linked di-ubiquitin probes bearing dehydroalanine as a warhead near the isopeptide bond has been described [ 85 ] . finally, abps engineered for di-ubiquitin chains incorporating the 8 known ubiquitin linkages have been successful and now allow dub ubiquitinlinkage specifi city in a cellular context to be addressed [ 86 -88 ] . structural studies of dubs with di-ubiquitin have demonstrated that in addition to the peptide fl anking the ubiquitylated residues, more extensive interactions between dubs and the proximal ubiquitin in the chain also contribute to the recognition by dubs. probing dub selectivity with the latest generation of probes not only generates a distinct pattern from that obtained using mono-ubiquitin abps, but also suggests that the promiscuity of some dubs for their substrates is probably much less pronounced than initially anticipated. in the last couple of years, posttranslational modifi cations of ubiquitin, especially phosphorylation of ubiquitin at specifi c residues (e.g., ser57 and ser65) have been shown to play important roles in a number of cellular processes [ 89 , 90 ] . ubiquitin abps bearing the phosphorylated variants of ubiquitin have been generated and used to probe the selectivity of the modifi cations for conjugating and deconjugating enzymes. e1 and e2 enzymes are usually able to tolerate phosphorylated ubiquitin, however, a number of dubs have diffi culty recognizing the modifi ed substrates [ 91 , 92 ] . studies evaluating additional posttranslational modifi cations of ubiquitin such as methylation, acetylation, hydroxylation, or other phosphorylation will certainly be unraveled in the near future: the corresponding abps will again serve as useful tools to understand the mechanistic and physiological role of novel variants of ubiquitin. a key issue facing researchers involved in deciphering the roles of dubs in a cellular context is the lack of understanding of the most direct or relevant substrate of specifi c dubs in a given cellular pathway. some dubs have very well characterized substrates (e.g., usp1 or usp7) [ 15 ] that are clearly linked to the function of the dubs, however, the known substrate specifi city is still relatively poor or partial at best for most dubs. in certain cases, it is quite clear that unique substrates do not exist: e.g., usp14 or uchl5 are dubs that indiscriminately recognize any ubiquitylated substrates which is targeted to the proteasome [ 93 ] . ubiquitin abps can play a critical role as tools to monitor the dynamics of the activation or inhibition of dubs under specifi c physiological or pharmacological pathway alterations. the problem is especially acute for the monitoring of dub activity upon inhibition with specifi c inhibitors: the pharmaceutical development of dub inhibitors requires a good understanding of the pharmacokinetic modulation of the target upon treatment with compounds. the development of abps for proteomic evaluation of target engagement is currently being investigated by a number of groups. in addition, higher throughput abp-based strategies are also under development for the determination of dub target engagement in cellular contexts as well as in tissues or eventually for clinical sample evaluation (fig. 3 ) . the development of activity probes for dubs has lagged behind the development of probes for more classical proteases. indeed, the complexity of the recognition site of dubs, which requires the binding of full-length ubiquitin in the catalytic site as well as the challenges in the characterization of potent and selective dub inhibitors , has hindered production of abps for dubs. however, following on from the ground-breaking evolution of cell-permeable and in vivo-compatible activity-based imaging probes developed for other proteases such as caspases or cathepsins [ 69 , 70 ] , the next generation of probes for dubs will certainly be agents that enable direct visualization and quantifi cation of dub activity in vivo. such noninvasive agents have great potential for early diagnosis as well as pharmacodynamic evaluation of dub inhibition in preclinical as well as clinical settings. one attractive avenue to explore for the development of selective dub activity probes is based on the design of copper-catalyzed click-labeled dub inhibitors with quenchable or nonfl uorescent labels [ 94 ] . click-labeled abps allows for selective labeling, visualization, and enrichment of active enzymes in a complex proteome. another approach will likely be based on the generation of noninvasive substrate probes that do not bind covalently to the enzyme. the advantage of this approach is based on the theoretically higher signal that can be generated, in contrast to covalent activity probes which are limited by the stoichiometric labeling of the enzyme (the signal being proportional to the amount of enzyme in various tissues). so far a very limited number of reporter substrates are available, none being cell permeable, or suitable for in vivo applications. again, noninvasive permeable substrates will likely be derived from selective inhibitors of individual dubs or knowledge around selectively ubiquitylated sites on dub substrates. probably one of the most promising avenues for developing cell-and tissue-permeable selective ubiquitin abps for dubs will rely on the modifi cation of selective small molecule inhibitors of dubs . similar approaches have already achieved some preliminary success for other enzymes of the ups such as e1 enzymes [ 95 ] and proteasome probes [ 96 ] . the limiting step in developing such probes for dubs is currently a lack of potent, specifi c and selective dub inhibitors available, however, the community is successfully designing novel generations of selective dub inhibitors. while a number of abps have been successfully designed for monitoring the activity of cysteine peptidase dubs , there is still a gap in the development of abps for dubs of the metalloenzyme class (mpn+/jamms) . a number of approaches are currently being investigated for the design of abps for metallo-dubs and will certainly aid the characterization of inhibitors for that class of enzymes which is showing great promise as therapeutic targets [ 97 -99 ] . protein ubiquitylation is critical for the control of protein half-life, localization, and function. deregulation of this process is a causative factor of many diseases. the development of abps has allowed for major advancement in the identifi cation and characterization of cysteine dubs. signifi cant progress has been made in terms of probe design and preparation. for example, fi ve papers have been published in the past 3 years describing di-ubiquitin abps, underscoring the importance of these tools for dub research. the jamm family remains diffi cult to target using abps due to the catalytic mechanism which does not involve a covalent dubsubstrate intermediate. hopefully new approaches and novel probe designs will yield better tools to investigate this class of metalloproteases. abps will ultimately shed light on the function and relevance of dubs involved in various chain-specifi c ubiquitin signaling, and will continue to advance our knowledge of dub regulation and function in a cellular context. furthermore, abps will aid the development and characterization of dub inhibitors , allowing the monitoring of target engagement as well as selectivity in vivo. finally, while ubiquitin abps have not yet been as broadly used as one might expect to monitor dubs in developmental or pathological evaluations, they can provide a unique dynamic assessment of the activity of dubs, and will undoubtedly become a more familiar option for many researchers. ubiquitin-like protein conjugation and the ubiquitin-proteasome system as drug targets mdc1 is required for the intra-s-phase dna damage checkpoint diversity of 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understanding ubiquitin-modifying enzymes: from pharmacological targeting to proteomics deubiquitylating enzymes and dna damage response pathways ubiquitin chain conformation regulates recognition and activity of interacting proteins dubs, the regulation of cell identity and disease small-molecule inhibitor of usp7/hausp ubiquitin protease stabilizes and activates p53 in cells discovery of specifi c inhibitors of human usp7/hausp deubiquitinating enzyme a small molecule inhibitor of ubiquitin-specifi c protease-7 induces apoptosis in multiple myeloma cells and overcomes bortezomib resistance a novel small molecule inhibitor of deubiquitylating enzyme usp14 and uchl5 induces apoptosis in multiple myeloma and overcomes bortezomib resistance targeting deubiquitinase activity with a novel small molecule inhibitor as therapy for b-cell malignancies activity-based protein profi ling: from enzyme chemistry to proteomic chemistry activity-based protein profi ling: the serine hydrolases developing photoactive affi nity probes for proteomic profi ling: hydroxamate-based probes for metalloproteases activity-based probes for the proteomic profi ling of metalloproteases activity probe for in vivo profi ling of the specifi city of proteasome inhibitor bortezomib proteomic profi ling of mechanistically distinct enzyme classes using a common chemotype mechanism-based proteomics tools based on ubiquitin and ubiquitin-like proteins: crystallography, activity profi ling, and protease identifi cation a novel active sitedirected probe specifi c for deubiquitylating enzymes reveals proteasome association of usp14 chemistry-based functional proteomics reveals novel members of the deubiquitinating enzyme family otubains: a new family of cysteine proteases in the ubiquitin pathway chemistry-based functional proteomics: mechanism-based activityprofi ling tools for ubiquitin and ubiquitin-like specifi c proteases on terminal alkynes that can react with active-site cysteine nucleophiles in proteases fluorescence-based active site probes for profi ling deubiquitinating enzymes ubiquitin-based probes prepared by total synthesis to profi le the activity of deubiquitinating enzymes chemical synthesis of ubiquitin, ubiquitin-based probes, and diubiquitin structural basis of ubiquitin recognition by the deubiquitinating protease usp2 muscle wasting in aged, sarcopenic rats is associated with enhanced activity of the ubiquitin proteasome pathway activity-based ubiquitinspecifi c protease (usp) profi ling of virusinfected and malignant human cells a deubiquitinating enzyme encoded by hsv-1 belongs to a family of cysteine proteases that is conserved across the family herpesviridae structure of a herpesvirus-encoded cysteine protease reveals a unique class of deubiquitinating enzymes chlamydia trachomatisderived deubiquitinating enzymes in mammalian cells during infection apicomplexan uchl3 retains dual specifi city for ubiquitin and nedd8 throughout evolution identifi cation by functional proteomics of a deubiquitinating/deneddylating enzyme in plasmodium falciparum chladub1 of chlamydia trachomatis suppresses nf-kappab activation and inhibits ikappabalpha ubiquitination and degradation the sars-coronavirus papain-like protease: structure, function and inhibition by designed antiviral compounds systematic and quantitative assessment of the ubiquitin-modifi ed proteome improved quantitative mass spectrometry methods for characterizing complex ubiquitin signals dynamics of cullin-ring ubiquitin ligase network revealed by systematic quantitative proteomics defi ning the human deubiquitinating enzyme interaction landscape functional annotation of deubiquitinating enzymes using rna interference deubiquitinase activities required for hepatocyte growth factor-induced scattering of epithelial cells systematic survey of deubiquitinase localization identifi es usp21 as a regulator of centrosome-and microtubuleassociated functions systematic characterization of 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sensitivities of e1-e2 enzymes and deubiquitinases the proteasome under the microscope: the regulatory particle in focus applications of copper-catalyzed click chemistry in activity-based protein profi ling development of activity-based probes for ubiquitin and ubiquitin-like protein signaling pathways activity-based imaging probes of the proteasome endocytosis: the dub version jamm: a metalloprotease-like zinc site in the proteasome and signalosome cop9 signalosome function in the ddr the authors would like to acknowledge networking support by the proteostasis cost action (bm1307) . key: cord-307983-gjdza9bh authors: hawdon, james; parti, katalin; dearden, thomas e. title: cybercrime in america amid covid-19: the initial results from a natural experiment date: 2020-06-10 journal: am j crim justice doi: 10.1007/s12103-020-09534-4 sha: doc_id: 307983 cord_uid: gjdza9bh the covid-19 pandemic has radically altered life, killing hundreds of thousands of people and leading many countries to issue “stay-at-home” orders to contain the virus’s spread. based on insights from routine activity theory (cohen & felson 1979), it is likely that covid-19 will influence victimization rates as people alter their routines and spend more time at home and less time in public. yet, the pandemic may affect victimization differently depending on the type of crime as street crimes appear to be decreasing while domestic crimes may be increasing. we consider a third type of crime: cybercrime. treating the pandemic as a natural experiment, we investigate how the pandemic has affected rates of cybervictimization. we compare pre-pandemic rates of victimization with post-pandemic rates of victimization using datasets designed to track cybercrime. after considering how the pandemic may alter routines and affect cybervictimization, we find that the pandemic has not radically altered cyberroutines nor changed cybervictimization rates. however, a model using routine activity theory to predict cybervictimization offers clear support for the theory’s efficacy both before and after the pandemic. we conclude by considering plausible explanations for our findings. presence of a suitable target, and (3) the absence of a capable guardian. routine activity theory proposes that victimization stems from the "recurrent and prevalent activities" that individuals are involved in, which in turn influence the likelihood that the three necessary factors are present (cohen & felson, 1979) . therefore, routines influence an individual's risk of being victimized. while rat cannot be directly applied to the online world (see yar, 2005; yar, 2013; tillyer & eck, 2009) , the cyberlifestyle-routine activities perspective (see reyns, henson, & fisher, 2011; eck & clarke, 2003) overcomes the primary issue limiting the theory's applicability. most notably, while offline victimization requires a convergence in time and space of offenders and victims, cybervictims and offenders can come into virtual contact through their networked devices, and this contact can happen asynchronously (leukfeldt & yar, 2016; reyns et al., 2011; vakhitova, reynald, & townsley, 2015) . with this modification in mind, online routine activities can increase the likelihood of victimization by bringing potential targets into virtual contact with offenders in environments lacking guardians (see eck & clarke, 2003; reyns et al., 2011) . researchers have now applied rat to a variety of types of cybervictimization, ranging from fraud and identity theft to harassment and other forms of cyberviolence (e.g., bossler & holt, 2009; bossler, holt, & may, 2012; costello, hawdon, ratliff, & grantham, 2016; hawdon, bernatzky, & costello, 2019; hawdon, oksanen, & räsänen, 2015; hawdon, oksanen, & räsänen, 2017; holt & bossler, 2008; holt & bossler, 2013; marcum, higgins, & ricketts, 2010; navarro & jasinski, 2012; navarro & jasinski, 2013; pratt, holtfreter, & reisig, 2010; reyns, 2013; reyns & henson, 2015; van wilsem, 2011) . studies using rat to predict cybervictimization generally find that engaging in risky online behaviors such as downloading games and music from unknown websites, using file-sharing programs, instant messaging, opening unknown email attachments, and clicking on pop-up messages increases cyberharassment (hinduja & patchin, 2009; marcum, 2009; marcum et al., 2010; navarro & jasinski, 2012) . similarly, general computer use, anonymously confiding in others online, playing video games, spending time in chatrooms, online shopping, and the use of social networking sites, and adding strangers as friends to the social networking accounts have been reported to increase the likelihood of being a victim of cyberviolence (e.g. bossler & holt, 2009; bossler et al., 2012; costello et al., 2016; hawdon, oksanen, & räsänen, 2014; holt & bossler, 2008; leukfeldt & yar, 2016; navarro & jasinski, 2012; reyns et al., 2011; reyns, henson, & fisher, 2016; van wilsem, 2011) . the use of target-hardening devices such as antivirus programs, firewalls, and filtering and blocking software can potentially reduce cybervictimization, although the effect may only apply to economic victimization (e.g., leukfeldt, 2014; marcum, 2008; marcum et al., 2010) . as mentioned above, the stay-at-home orders enacted to combat the spread of covid-19 have radically altered the daily routines or millions of americans. with decreased mobility due to shelter-in-place orders, people are increasingly teleworking. according to one study, 88% of organizations have encouraged or required their employees to work from home because of the pandemic (gartner, 2020) . in addition to more people relying on technology to telework, the use of social media sites such as tiktok, twitter, facebook, and instagram are also spiking (yitzhak, 2020) . as we spend more time online, our cyber-routines change, and we would anticipate these changes would alter cybervictimization rates. but how specifically would the covid-19 pandemic likely alter our proximity to motivated offenders, suitability as a potential target, and online guardianship? let us speculate on each of these. covid-19 and virtual proximity to motivated offenders first, the unemployment rate has surged above 20% and is expected to reach levels not seen since the great depression, millions have lost their jobs, had their hours reduced, or have been furloughed, and the nation's small business owners are struggling to remain in business (bartash, 2020; lambert, 2020; wolfer, 2020) . as a revised version of rat argues (see bryant & miller, 1997) areas with large secondary labor markets have high crime rates in part because workers in the secondary sector frequently experience unemployment, which may compel them to find alternative means of support. thus, the radical shift in the employment structure of the nation to which these dire economic numbers attest has likely led to heightened economic need and increased motivations to steal. combined with the increase in the number of people going online, we would anticipate an increase in the virtual presence of motivated offenders in cyberspace. the increased presence of motivated offenders in cyberspace during the pandemic, assuming it is indeed the case, should increase overall rates of cybervictimization. while this proposition is likely to be true, motivated offenders are a necessary but not sufficient condition for victimization. indeed, cohen and felson (1979) assumed such offenders were omnipresent, and this truism is probably even more enhanced in cyberspace because its asynchronous nature allows offenders to be "virtually present" even when they are not personally online. thus, while more motivated offenders being online is likely to elevate rates of cybervictimization, the overall patterns are likely more affected by changes in target suitability and guardianship that result from the pandemic. covid-19 and target suitability independent of the number of offenders prowling virtual space, the online routines of potential victims also shapes their likelihood of being victimized by determining a target's suitability. suitable targets include any person or object that can fulfill the needs or wants of a motivated offender (cohen & felson, 1979) , and target suitability is a function of viva: the target's value, inertia, visibility, and access (felson & clarke, 1998) . value is the worth a person or object has in the eyes of a potential offender, inertia is the target's ability to avoid the offender, access is the opportunity for an offender to commit the illegal act, and visibility is the extent to which offenders can see a possible victim. these factors are interrelated and also related to the extent of contact targets have with motivated offenders. it is likely that the pandemic would influence target suitability in several ways. as noted above, the pandemic has resulted in people spending more time online. all things being equal, spending more time online would increase the potential victim's visibility to likely offenders. indeed, research indicates that the proportion of users who access the internet only from home is positively related to cybertheft victimization (song, lynch, & cochran, 2016) . however, simply spending more time online may not necessarily result in a greatly enhanced probability of being victimized because overall time spent online is likely less important than the specific online activities in which one engages. for example, spending 8 hours online teleworking is probably not likely to bring one into a virtual space where motivated offenders lurk. in contrast, spending even 1 hour surfing the dark web very well might increase one's exposure to motivated offenders. thus, online activities that lead one to visit "dangerous virtual spaces" will increase a potential target's visibility and the offender's access more so than those activities that occur in more secure online spaces (see costello, barret-fox, bernatzky, hawdon, & mendes, 2018; räsänen et al., 2016) . how the covid-19 pandemic and resulting stay-at-home orders will likely affect target suitability is undoubtedly complex. for example, as previously mentioned, the limited available evidence suggests that some activities known to be related to victimization because they may lead users into dangerous virtual spaces have undoubtedly increased (yitzhak, 2020) . these "dangerous" online routines would include surfing the dark web, playing online video games, online shopping, and visiting social media sites as all of these activities have been reported to increase cybervictimization (bossler & holt, 2009; bossler et al., 2012; costello et al., 2016; hawdon et al., 2014; leukfeldt & yar, 2016; navarro & jasinski, 2012; reyns et al., 2011; van wilsem, 2011) . all of these activities would increase the target's visibility and the offender's access, and we would anticipate that increases in these behaviors would result in higher rates of cybervictimization. however, time spent performing other online routines, such as working online or reading the news, may have also increased due to the pandemic, but these activities are unlikely to affect cybervictimization since they would not bring one into "dangerous" virtual spaces. another factor that can influence target suitability by decreasing an offender's access and possibly increase the target's ability to avoid an attack (i.e. decrease the target's inertia) is the use of target-hardening devices. some evidence suggests that the use of antivirus programs, firewalls, and filtering and blocking software can reduce the likelihood of becoming a victim of an economic cybervictimization; however, there is little evidence such devices can protect one from violent cybercrimes (see holt & bossler, 2008; leukfeldt, 2014; marcum et al., 2010) . how the pandemic would influence the use of target-hardening devices is difficult to predict. while one would hope people would be more vigilant in terms of updating their anti-virus software and making sure their firewalls are set, the pandemic has probably not influenced the overall use of computer technology for those with high levels of computer skills since these people were probably frequent users prior to the pandemic. instead, the pandemic has probably led to more inexperienced and unsophisticated computer users spending more time online. if this is the case, we would predict that overall rates of economic cybervictimization should increase. we note here that we would not expect violent cybercrimes to increase since these are reportedly unaffected by target-hardening devices. finally, another factor that patterns victimization is guardianship. guardianship is "the presence of a human element which acts-whether intentionally or not-to deter the would-be offender from committing a crime against an available target" (hollis, felson, & welsh, 2013: 76) . the findings with respect to guardianship and cybercrime are inconsistent (e.g., bossler & holt, 2009; leukfeldt & yar, 2016; reyns, 2015) , in part due to conceptual uncertainty across both study design and types of victimization (vakhitova & reynald, 2014 ). yet, as argued by costello, hawdon, and ratliff (2017) , the virtual world is a truly socially disorganized community. in cyberspace, actors are truly transient as they come and go regularly, and they do so anonymously. moreover, many online spaces have no way for anyone even trying to monitor the activity to intervene, and most offenders likely know this. even sites that closely monitor activity and have policies to censor or delete material struggle to keep pace with the amount of activity that must be monitored. moreover, online norms that would stimulate intervention on one's behalf tend to be weak and underdeveloped (see costello et al., 2017) . thus, overall guardianship is always low online and the pandemic is unlikely to have changed that. as such, we would not anticipate rates of cybervictimization to have changed due to any influence the pandemic would have had on cyber guardianship. taking all of these factors together, we would anticipate an increase in cybervictimization amid the covid-19 pandemic due to more motivated offenders, a change in some "dangerous" online routines, and perhaps less target-hardening. however, given that many online routines that have likely increased would not necessarily result in increased victimization and the fact that guardianship is likely unchanged by the pandemic (because it is always lacking online), any observed increase is expected to be modest. the above discussion gives rise to the following hypotheses that will be tested using samples collected pre (november 2019) and post (april 2020) pandemic. first, as stated above, given the anticipated changes in online routines, we hypothesize (h1) rates of cybervictimization will be modestly higher among post-covid-19 respondents than they are among pre-covid-19 respondents. next, as explained above, we anticipate the increase in victimization because people were forced to shift their daily activities online and radically enlarge their digital footprint. thus, we hypothesize that (h2) the extent to which respondents engage in online activities will be higher in the post-covid-19 sample than in the pre-covid-19 sample. we now turn to our analysis. data were collected using online panels from dynata. dynata uses random digit dialing, banner ads, and other permission-based techniques to recruit respondents. from this database dynata randomly invites panel members to participate in the survey. the sample was balanced based on us census data to represent sex, ethnicity, and race. online proportional sampling has been found to yield similar results as random probability-based samples due to several strategies (weinberg, freese, & mcelhattan, 2014; simmons & bobo, 2015; contrast macinnis, krosnick, ho, & cho, 2018) . first, both repeat participants and individuals who speed through the survey are eliminated to increase sample validity (wansink, 2001; evans & mathur, 2005) . in addition, the rewards offered by the panel company have been shown to increase validity of the overall data (see wansink, 2001 ). the first survey was fielded between november 24 and november 30, 2019 (pre-covid-19 sample), and the second was fielded between april 14 and april 17, 2020 (post-covid-19 sample). overall, 1315 respondents began the pre-covid-19 survey, but 81 respondents completed the survey in less than 3 min and were considered "speeders." they were removed from the sample. in addition, 125 participants did not complete the survey and were eliminated from the analysis. in total, 1109 respondents had usable data and were included in our analysis. in the post-covid-19 sample, 1120 respondents began the survey, with 58 "speeders" who were dropped from the analysis. dropping these respondents resulted in a sample of 1021 participants in the post-covid-19 sample. a comparison between the pre-covid-19 and post-covid-19 sample in terms of demographics can be found in table 1 . of note was an expected increase in unemployment in the post-covid-19 sample. in addition, the samples differed in average age and education, but did not differ in terms of racial/ethnic composition or gender. to examine the first hypothesis, we investigate rates of cybervictimization in the two samples. to measure cybervictimization, respondents were asked if they had been a victim of seven different types of cybercrime (see table 4 for the types of crimes and survey items used to measure them). we created a summated variable of all victimization behaviors. this count variable reflected the number of different victimization experiences the participants had experienced in the past 12 months. even upon visual inspection we noticed that, if anything, victimization was slightly higher in the pre-covid-19 sample. we examined victimization in relation to the samples using a negative binomial regression because our data are over-dispersed count data. we examined the differences between the samples by regressing victimization on a covid-19 indicator variable (0 = pre-covid-19; 1 = post-covid-19). the covid-19 indicator variable failed to reach standard levels of statistical significance, and the overall model had extremely low predictive power, with a pseudo r 2 of <.001. as such, our first hypothesis is not supported, at least when we consider overall cybervictimization. given that certain types of cybercrimes may have increased while others decreased, we also examined specific victimization and self-protection behaviors between the pre and post-covid-19 sample to help understand why we were not seeing a difference between the samples. we utilized χ 2 tests to consider differences between the samples. types of victimizations tested included scams, identity theft, unknown transactions, notification from organizations about data theft, online bullying, online sexual harassment, and malware/viruses. only one significant difference was found. the post-covid-19 sample reported fewer notifications by companies that their data had been stolen (χ2 = 7.97(1), p = .005). in the pre-covid-19 sample 21% of respondents indicated they had been notified by a company about data loss whereas in the post-covid-19 sample only 16% indicated they had been notified by a company about data loss. we also examined differences in self-protection measure use in the pre/post-covid-19 samples using similar χ 2 tests. only one significant difference was found. while 70% of the post-covid-19 sample indicated that they used virus software or firewalls, only 66% of the pre-covid-19 reported that they did (χ 2 = 3.97(1), p = .046). we advise caution in interpreting this result as the p value was close to .05 and we ran a total of 11 χ 2 tests, increasing the likelihood of a false positive. all victimization and self-protection difference tests can be found in table 2 . to test our second hypothesis regarding differences in computer behaviors between the samples, we compared pre-covid-19 and post-covid-19 computer-related activities. these activities include playing online games, reading news or other articles online, browsing social media, using a computer while working, and shopping online. as seen in table 3 , only one activity, reading news or other online articles was significantly higher in the post-covid-19 sample (t = −4.4(2093), p < .001). therefore, our second hypotheses is also not supported. given the failure of either of our hypotheses to be supported, we investigate if the rat model still applies to cybervictimization in the post-covid-19 world. given the reported fourfold increase in cybercrimes during the pandemic (cimpanu, 2020; england, 2020) yet our data not reflecting such an increase, we need to consider if to do this, we turn to a test of rat using our two samples. to examine if rat is an adequate predictor of cybervictimization, we included several variables in a negative binomial regression. the model included an index variable of pre/post-covid-19 sample, time spent in the various online activities mentioned above, computer self-protection behaviors, and demographic variables. table 4 reports the results of the analysis. overall the model was significant (p < .001). factors related to increased risk of victimization included dark web use per week (irr = 1.14; p < .001), time reading online news/articles (irr = 1.08; p < .001), time browsing social media (irr = 1.04; p < .05) and age (irr = 1.02; p < .001). age was the only demographic factor to achieve statistical significance in the model. factors significantly related to lower risk of victimization included time working on a computer (irr = 0.95; p < .005) and all protective behaviors including covering a webcam (irr = 0.70; p < .001), having identity theft protection (irr = 0.78; while the covid-19 indicator was again not significant, almost all of the ratspecified variables were significant predictors in the model, and all of the relationships between these variables and cybervictimization were in the direction rat would predict. it is also worth noting that age was the only demographic variable that was significantly related to cybervictimization. this finding is also supportive of rat's argument that one's routines determine victimization. finally, we tested to see if any interaction between the covid-19 indicator variable and the rat variables were significant to be certain that rat applied equally well in the pre and post covid-19 world. results (not shown here) indicated that no interactions were significant, suggesting that indeed rat still performs well as an explanation of cybervictimization even during the pandemic. to our knowledge, our study is the first empirical evidence concerning how the covid-19 pandemic influenced cyber-routines and cybervictimization. we assumed that the pandemic and the results of stay-at-home orders would result in increased online presence, an increased level of routine activities online, and, as such, enhanced levels of target suitability and target proximity to motivated offenders. consequently, we expected that rates of cybervictimization would be higher in the post-pandemic sample than what was observed in the pre-pandemic sample. the results show that we were clearly wrong. based on our results, the stay-at-home orders did not radically alter our cyber-routines, and cybervictimization did not increase either. instead, global levels of cybervictimization were nearly identical pre and post-pandemic, and only one type of victimization (being informed that your identity or private information had been stolen) changed. moreover, this victimization decreased in the post-covid-19 sample. among the indicators of cyber-routine activities, including playing online games, a scale is nonlinear as hours were represented in increasing increments, 0, <1, 1-2, 2-4, 4-6, 7-8, 8-10, 10 or more *p < .05, **p < .01, ***p < .001 reading news or other articles online, browsing social media, using a computer while working, and shopping online, only reading news or other online articles increased. one online activity, online shopping, even decreased in the post-covid-19 sample. we also wanted to see if specific types of victimization and protection behaviors changed after the pandemic. among all the specific victimization variables, only one showed a significant difference: there was less notification from companies concerning data theft in the post-covid-19 sample. in terms of target-hardening behaviors, participants reported using more self-protection (i.e. virus software and a firewall) in the post-covid-19 sample. thus, while there were minor differences between the samples, contrary to our expectations and fbi reports (cimpanu, 2020; england, 2020) , our data show that the pandemic has not radically altered our cyber-routines or levels of cybervictimization. fearing rat may not apply in the post-pandemic virtual world, we tested it with a negative binominal regression. our model showed dark web use, time spent online reading newspapers and other articles, and time using social media significantly increased the likelihood of being a cyber victim. time spent working on a computer, protective behaviors such as covering the webcam, having identify theft protection, freezing credit, and having virus protection were all inversely related to the likelihood of victimization. these results clearly support rat, and the insignificance of the covid index variable or any interactions between it and the various cyber-routines indicate that the theory applies equally well in the pre and post covid-19 world. although cybervictimization has not changed substantially, our binominal regression model indicates that rat can account for patterns of cybervictimization in both pre and post-pandemic samples. so why were our expectations so wrong? first, proximity to motivated offenders may have increased as people went online to work, study, and network, but target suitability did not increase as, according to our results, people likely used online platforms similarly to how they had before the pandemic. most of their online behaviors did not put them at more than average risk of victimization. there was no evidence that dangerous online behaviors such as dark web use, online shopping, or visiting social media platforms changed significantly after the pandemic. indeed, our data suggest users abandoned online activities such as online shopping that would pose risk to their bank accounts. instead, it seems that people kept their cyber-routines concentrating on less dangerous routine activities, such as working online and reading news articles. the online routine activity that significantly increased was reading online news, but that activity would not heighten victimization as most traditional online news sites are reputable and do not increase their readers' target suitability. we also expected that the overall rates of cybervictimization, and especially economic cybervictimization, would increase because of the nation's swift shift to the virtual world likely did not leave time for users to upgrade their computer security measures (e.g. firewalls, anti-virus software, etc.). while more computer savvy users likely have security measures already installed, those with fewer computer skills could be more vulnerable now that they are spending more time online. however, our data indicated that more people engaged in target-hardening measures and cybervictimization was unrelated to computer familiarity. a plausible explanation for this is that workers' relatively unfamiliar with computers were moved online by their companies who provided sufficient it support. we cannot say this happened, but it is likely that corporations were keenly aware that some of their less-thantech-savvy employees who were now teleworking needed support and failing to do so could put their company at heightened risk. indeed, there is reason to suspect there was heightened concern about cybercrime and possibly greater vigilance practiced to protect oneself from it. for example, the fbi noted how cybercriminals would likely target both companies and individuals working from home via teleworking software, education technology, and business email platforms. on april 15, the us departments of state, homeland security, and treasury, and the fbi issued an advisory to raise awareness of the cyber threat posed by north korea's malicious cyber activities, a significant threat to the integrity and stability of the international financial system (us cert, 2020). on april 20, the fbi charlotte warned (fbi charlotte, 2020) social media users to pay attention to trending social media topics (e.g. high school support photo trend, posting a picture of your first car, answering questions about your best friend, providing the name of your first pet, identifying your first concert, etc.), which might collect users' personal information, including passwords to reset accounts and gain access to protected data. thus, it is possible that these warnings worked. while we lack the data to adequately test if companies' policies attempted to protect their users or the government warnings worked, this possibility should be further explored by future research. our data allows us to say that the relative unchanged nature of our respondents' "dangerous" cyber-routines combined with their use of stronger security measures such as antivirus software and firewalls likely kept cybervictimization low, even if there was elevated motivation among offenders due to souring rates of unemployment and economic struggles. we can also say that our findings contradict recent reports about heightened levels of cybercrime being reported to the fbi (cimpanu, 2020; england, 2020; ic3, 2020) . like us, the fbi anticipated that virtual environments will be increasingly affected adversely by cybercriminals, and as of march 30, 2020 (ic3, 2020), their data gives credence to their fears. the fbi internet crime complaint center (ic3) reports receiving more than 1200 complaints related to covid-19 scams, including phishing campaigns against first responders, ddos attacks against government agencies, ransomware against medical facilities, and fake covid-19 websites downloading malware to users' computers. in total, the fbi reports cybercrimes have quadrupled during the covid-19 pandemic (cimpanu, 2020; england, 2020) . how do our results showing decreased cybervictimization make sense when cybercrime has an upward trend in the news and in fbi reports? it might just show the usual discrepancies between official crime statistics relying on reporting and victimization surveys. it is well documented how official statistics seriously underestimate crime rates. what we might be seeing is that while rates of crime are actually unchanged, rates of reporting crimes is increasing. the repeated warnings of federal and state law enforcement and international policing agencies about the expected increase in cyber-offending may alert people and lead them to the dangers of cybercrime. this heightened awareness would then lead them to notice and report these crimes more than they did prior to the pandemic. another possibility is that the increased rates of reporting to the fbi are more due to attacks on companies than on individual users. our data focused on individual, not corporate, victimization. thus, because our survey only included individual level cybervictimization while ignoring attacks on companies and critical infrastructures, we may not be detecting the increase in cybercrimes through our victimization surveys. this possibility should also be investigated by future researchers. our lives have been radically altered by a pandemic that is considered to be among the most widespread in history. the change in our daily routines appears to have resulted in an abrupt drop in street crimes. however, the shift to the digital world undoubtedly creates new opportunities and platforms for motivated offenders to engage in various illegal activities. this shift should increase the number of suitable targets, as millions of people are confined to their homes and forced to work, study, and socialize online. the current shift was swift, but, at least according to our data, this shift apparently did not result in people being more affected by cybercrime. they may be reporting more of it, but it is also possible that the pandemic has led to a decrease in most street crimes, an increase in domestic crimes, and no change in cybercrimes. the reasons of the crime drop experienced all over the world in the 1990s (pope & pope, 2012) is still debated (rosenfeld & messner, 2012) and is indeed a complex issue. it is likely the current crime trends will be studied and debated for some time too. our aim here was simply to provide one piece of evidence that will hopefully significantly contribute to that future analysis and debate. we live in unprecedented times. we did not, nor can we, measure every possible underlying reason why cybervictimization occurs. we cannot predict if cybervictimization will remain low as social distancing continues. however, we can say that routine activities theory appears to still apply. we live in unprecedented times, but we still have theories to help us make sense of them. thomas dearden : is assistant professor of sociology at virginia tech. dr. dearden specializes in research technology and crime, and corporate crime. he has conducted research for organizations across the globe, including the polynesian cultural center in hawaii, food for life vrindavan in uttar pradesh, india, and pay tel in north carolina. he has published his research in peer-reviewed journals including the journal of financial crime and the journal of investigative 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pursued online applying cyberlifestyle-routine activities theory to cyberstalking victimization guardians of the cyber galaxy: an empirical and theoretical analysis of the guardianship concept from routine activity theory as it applies to online forms of victimization the crime drop in comparative perspective: the impact of the economy and imprisonment on american and european burglary rates the international crime drop. crime prevention and security management staying home saves lives can non-full-probability internet surveys yield useful data? a comparison with full-probability face-to-face surveys in the domain of race and social inequality attitudes a macro-social exploratory analysis of the rate of interstate cyber-victimization routine activities north-korean cyber threat cyberguardians: an empirical study of guardianship against cyber abuse toward the adaptation of routine activity and lifestyle exposure theories to account for cyber abuse victimization worlds tied together? online and non-domestic routine activities and their impact on digital and traditional threat victimization editorial: the power of panels comparing data characteristics and results of an online factorial survey between a population-based and a crowdsource-recruited sample the unemployment rate is probably around 13 percent. the new york times accessed 3 the novelty of 'cybercrime': an assessment in light of routine activity theory cybercrime and society social media interest is spiking worldwide-except for linkedin. the next web the great american crime decline publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations james hawdon : is a professor of sociology and director of the center for peace studies and violence prevention at virginia tech. he researches how communities influence the causes and consequences of violence. most recently, he has focused on how online communities influence political polarization, online hate, extremism, and cybercrime. he has been funded by the national science foundation, the national institute of justice, the national consortium on violence prevention, and several other agencies she evaluated cyberbullying programs of the massachusetts aggression reduction center as a fulbright fellow, and was awarded the european safety and prevention award for channeling academic research results to schools. she has published in peer-reviewed journals such as the pediatrics, the acknowledgements this research was funded by the center for peace studies and violence prevention at virginia tech (grant number 025-19), the institute for culture, society, and environment at virginia tech, and the integrated security destination area at virginia tech. key: cord-256992-rwy0n01l authors: taheri, yasaman; suleria, hafiz ansar rasul; martins, natália; sytar, oksana; beyatli, ahmet; yeskaliyeva, balakyz; seitimova, gulnaz; salehi, bahare; semwal, prabhakar; painuli, sakshi; kumar, anuj; azzini, elena; martorell, miquel; setzer, william n.; maroyi, alfred; sharifi-rad, javad title: myricetin bioactive effects: moving from preclinical evidence to potential clinical applications date: 2020-08-01 journal: bmc complement med ther doi: 10.1186/s12906-020-03033-z sha: doc_id: 256992 cord_uid: rwy0n01l several flavonoids have been recognized as nutraceuticals, and myricetin is a good example. myricetin is commonly found in plants and their antimicrobial and antioxidant activities is well demonstrated. one of its beneficial biological effects is the neuroprotective activity, showing preclinical activities on alzheimer, parkinson, and huntington diseases, and even in amyotrophic lateral sclerosis. also, myricetin has revealed other biological activities, among them as antidiabetic, anticancer, immunomodulatory, cardiovascular, analgesic and antihypertensive. however, few clinical trials have been performed using myricetin as nutraceutical. thus, this review provides new insights on myricetin preclinical pharmacological activities, and role in selected clinical trials. polyphenols are a wide group of plant-derived molecules resulting from secondary metabolism, ubiquitously distributed in vegetable kingdom where they display different activities such as protective effect against uv rays, bacteria, virus and fungi infections, modulation of plant hormones, enzyme inhibition and pollinator attraction [1] . in nature, there are a plethora of different polyphenols that can be classified in the following main classes: simple phenolic acids (e.g. gallic, vanillic, syringic, p-hydroxybenzoic), hydroxycinnamic acid derivatives (such as caffeic acid, p-coumaric, ferulic, sinapic), flavonoids, stilbenes and lignans. the largest common class of polyphenols present in human diet is represented by flavonoids [2, 3] . chemically flavonoids are classified in flavans, flavones, flavonols, and anthocyanidins [4] . among the flavonols, myricetin, a 3,3′,4′,5,5′,7-hexahydroxyflavone, possess one of the most hydroxylated structures (fig. 1) . the solubility of myricetin in water is poor (16.6 μg/ml) but increases when deprotonated in basic aqueous media and in some organic solvents (dimethylformamide, dimethylacetamide, tetrahydrofuran and acetone) [5] . the chemical stability of myricetin is ph and temperature dependent [6] . depending on the environment conditions, myricetin can exert, in vitro, both a potent antioxidant and a pro-oxidant effect. buchter et al. [7] attributed its direct antioxidant action to several structural elements. on the other hand, chobot and hadacek [8] demonstrated the pro-oxidative properties of myricetin to molecular oxygen reduction to reactive oxygen species (ros) and iron (iii) to iron (ii) and also highlighted the ability of myricetin to serve as a substitute for ascorbic acid, albeit less efficiently. myricetin is mainly present in the glycoside form (o-glycosides), in vegetables, fruits, nuts, berries, herbs, plants together with beverages, such as tea, wine, fruit and medicinal plants [9] [10] [11] [12] [13] [14] [15] . there are numerous factors that can influence myricetin levels in plant foods such as genetic and environmental factors, germination, and ripeness degree, variety, seasonal variation, and storage, processing and cooking. the estimate of total flavonoid intake is difficult to calculate, as appropriate tables of food composition are not yet available. however, reliable data on daily flavonoid intake in a population are needed to develop proper dietary recommendations and even for correct data interpretation from intervention studies. the flemish dietetic association database determined an average daily intake of myricetin of 2.2 ± 2.5 mg mullie et al. [16] . in a korean adult population, jun et al. [17] estimated an average intake of 0.8 mg/day representing about 1-2% of flavonol subclass, while a mean intake of myricetin 2 mg/day ranged from 1 to 4 mg/day in adults (18 to 64 years) in the european union was reported by vogiatzoglou et al. [18] . the knowledge on habitual flavonoids consumption is also crucial to determine their possible impact on human health. myricetin exhibited antioxidant properties and free radical-scavenging effects [19] . these activities seem to support a wide range of beneficial outcomes including, anti-platelet aggregation, antihypertensive, immunomodulatory, anti-inflammatory, anti-allergic, analgesic, anticancer actions and so on [6, [20] [21] [22] [23] [24] [25] . the main goal of the present review is to provide new insights on myricetin preclinical pharmacological activities, and its role in selected clinical trials. [27] . the first time myricetin was identified was in plants of the myricaceae, comptonia peregrina (l.) coult. and later morella cerifera (l.) small [28, 29] . the myricetin concentration in the plants such as rosa canina l. (rosa hip), urtica dioica l. (nettle), and portulaca oleracea l. (purslane) found between 3 and 58 mg/kg [13] . myricetin was isolated from polygonum bellardii all. (polygonaceae) as yellow needles (50 mg) from aerial parts using meoh extract [30] . previously, a prescreening of leaves of 28 polygonaceous plants was estimated that myricetin glycosides were relatively rare consituents [31] . trigonella foenum-graecum l. gemmo-modified extract had the richest content in myricetin (830 mg/kg), followed by euphorbia tirucalli l. (821 mg/kg), rhizomes of cyperus rotundus l. (702 mg/kg) and seed extract of t. foenum-graecum (547 mg/kg). c. rotundus gemmomodified extracts contained 104 mg/kg myricetin [10] . the highest level of myricetin content has been identified in the strawberry and spinach [9] . species of anacardium and mangifera (anacardiaceae) found to have high levels of hydroxylated compounds like myricetin, gallic acid, proanthocyanidins and flavonols. in marantodes pumilum (blume) kuntze (primulaceae) were identified quercetin, myricetin, kaempferol, catechin and epigallocatechin [32] . the most common sources of myricetin are vegetables, fruits, nuts, berries and tea [33] . myricetin-rich foods are listed in table 1 based on the usda food database (compiled data from all fruits and vegetables that contain information on myricetin concentration) [34] . in black fruits the quantities varied between 14 and 142 mg/kg [12] . myricetin is the most abundant flavonol of black currant, and its quantity varied significantly among black currant cultivars [35] . at the same time, honey is also a source of flavonoids, especially myricetin. the hplc analyses of honeys from australian eucalyptus have shown that the flavonoids myricetin, quercetin, tricetin, kaempferol and luteolin exist in all honeys. myricetin was found in range from 29.2-289.0 μg/100 g honey [36] . in grapes, flavonol glycosides from the following aglycons have been identified: myricetin (3′,4′, 5′-trioh), laricitrin (3′-meo analog of myricetin) and syringetin (3′,5′-dimeo analog of myricetin), quercetin and kaempferol [37] . the simultaneous presence of these aglycons was detected in different types of red wine vitis vinifera l. grapes [38] , while in white wine, only quercetin, kaempferol and isorhamnetin were detected [37] . myricetin displays multiple preclinical biological effects [19] . thus, in the following subsections, the antimicrobial, antioxidant, neuroprotective, antidiabetic, anticancer, immunomodulatory, cardioprotective, analgesic, anti-hypertensive and wound healing potential of myricetin are briefly discussed and summarized. antimicrobial mechanism of flavonoids may involve membrane disruption, inhibition of cell envelope synthesis, inhibition of nucleic acid synthesis, inhibition of bacterial virulence and quorum sensing, which impairs their ability to form biofilms, inhibition of efflux pumps, and inhibition of nadh-cytochrome c reductase activity and atp synthase [39, 40] . myricetin inhibited escherichia coli dna gyrase (ic 50 1.18 mg/dl) [41] , and dnab helicase (ic 50 11.3 μm) [42] , and cellular dna and rna polymerases [43] . myricetin showed a significant antimicrobial activity against foodborne pathogens in terms of minimum inhibitory concentration (mic, mg/ml) <15.0, <15.0, < 20.0, <10.0 at 24 h and <20.0, <20.0, <15.0, <5.0 at 60 h incubation for escherichia coli, salmonella paratyphi, salmonella cholerasuis, and salmonella enteritidis, respectively [44] . the compound myricetin revealed curlidependent e. coli biofilm formation inhibition (ic 50 = 46.2 μm), curli contributes to the robustness of e. coli biofilms [45] . yadav et al. [47] demonstrated the anti-tubercular activity of 15 selected flavonoids including myricetin and their structure-activity relationships were evaluated against mycobacterium tuberculosis h37rv strain radiometrically. myricetin was found to be active against m. tuberculosis, with a mic of 50 μg/ml, and structure-activity relationships authenticated their anti-tubercular potential due to the presence of hydroxy groups in their structure. the inhibitory activity of the compounds were evaluated against dna gyrase from e. coli by dna supercoiling. mean antibacterial activity in terms of mic and ic 50 were 142 μg/ml and 1.18 mg/ml respectively. the structureactivity relationship analysis suggests that, the presence of hydroxyl and substitution in the ring a and b position are essential for the best inhibitory effects [41] . the inhibitory effect of myricetin on severe acute respiratory syndrome-coronavirus (sars-cov) helicase, nsp13, and hepatitis c virus (hcv) helicase, ns3h was also assessed [48] . myricetin was found to inhibit sars-cov helicase protein by affecting the atpase activity (ic 50 2.71 μm), however, it failed to affect the atpase activity of the hcv ns3 helicase. desouza and wahidullah [49] reported the antimicrobial activity on e. coli, klebsiella pneumoniae, proteus mirabilis, pseudomonas aeruginosa, salmonella typhi, shigella flexneri, staphylococcus aureus, vibrio cholerae and myricetin showed the best activity against p. aeruginosa (mic 1.5 μg/ml). gendaram et al. [50] reported the myricetin antibacterial effect against s. aureus by the disc diffusion method (300 μg/disc, inhibition zone 9 mm) but reported no antibacterial activities against p. aeruginosa, e. coli, enterococcus faecalis, or micrococcus luteus. however, at 100 μm concentration, myricetin did not exhibit antimicrobial activity on gram-positive bacteria but showed inhibitory activity against sortase a (srta) from s. aureus (92%; ic 50 4.63 μm) [51] . in vitro antimicrobial activity of six natural phytochemicals including myricetin (alone and with combination) were evaluated against five strains of p. aeruginosa by using a time-kill assay. the compound showed the mic as 500 μg/ml against all five strains of p. aeruginosa [52] . other reports of the compound based on antimicrobial and antiviral studies are presented in table 2 . plant-based compounds considered as natural antioxidants have attracted a large number of communities of scientist, researchers, industries and traditional healers for their health-promoting characteristics. the antioxidant table 1 myricetin (mg/100 g) rich foods [34] cranberry 6600 dock 5700 sweet potato leaves 4400 chard, swiss 3100 broadbeans, immature seeds 2600 rutabagas 2100 garlic 1600 blueberry 1300 peppers, hot chili, green 1200 blackberry 700 lotus root 600 lemon 500 source: usda food database (compiled data from all fruits and vegetables that contain information on myricetin concentration) potential of myricetin has been reported by several authors in the last few decades. hou et al. [61] studied the antioxidant effect of hs15-myr micelles and independent myricetin by using frap (ferric reducing antioxidant power) and abts (2,2′azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assays. the abts assay displayed an improved value from 22.20 to 41.77% in hs15-myr micelles and 0 to 6.12% in independent myricetin at two different concentrations and incubation periods. the frap assay also presented an improved value from 1.27 to 8.94 mm fe 2+ /g in hs15-myr micelles and 13.63 to 16.33 mm fe 2+ /g in independent myricetin at two different concentrations and incubation periods. myricetin in hs15-myr micelles exhibited in both assays stronger antioxidant effects when compared to independent myricetin. barzegar [62] reported the ros-protection efficiency of the compound myricetin in a cell-free and cell-based system. a low concentration of compound significantly inhibited intracellular ros production and also protected cells against toxicity induced by peroxide compounds. guitard et al. [63] reported that, myricetin is more efficient than α-tocopherol and synthetic antioxidants on preservation of omega-3 oils. other studies on antioxidant potential of the compound are presented in table 3 . natural flavonoids have exerted positive impacts on body through affecting multiple cell systems and modulating the activity of various pathways to reduce cognitive decline and neuronal dysfunction [79] . myricetin is one of such flavonoids, and multiple studies have been conducted to assess the neuroprotective effects of this compound and its interaction with brain receptors ( table 4 ). the main mechanisms are shown in fig. 2 . myricetin antidiabetic activity has been reported by several authors in the last few years and limited reports are also available on its anti-obesity activity but in this review, we focused on only its antidiabetic potential. karunakaran et al. [101] reported the in vitro effect of myricetin on high glucose-induced β-cell apoptosis, possibly via cyclin-dependent kinase 5 (cdk5) inhibition. data revealed that myricetin (20 μm) significantly protect β-cells reducing apoptosis in ins-1 cells and rat islets that were incubated with glucose at the concentration of 30 mm for 24 and 48 h, respectively. docking studies predicted myricetin inhibited activation of cdk5. the effect of myricetin was evaluated in diabetes mellitus-associated kidney injuries and dysfunction in an experimental mouse model with diabetes mellitus induced by 5 consecutive injections of low-dose streptozotocin (stz) [20] . the data revealed that myricetin (orally twice a day, 100 mg/kg/day, for 6 moths) inhibited the iκbα/nf-κb pathway, with this pathway being independent of nuclear factor erythroid 2related factor (nrf2) regulation. it was also reported that myricetin activates glucagon-like peptide 1 receptor (glp-1r) and its long-term oral administration (200 mg/kg, for 40 days) validates its glucoregulatory effects [102] . insulin's metabolic action is mediated via the activation of phosphatidylinositol 3-kinase (pi3k) and its downstream effectors, the protein kinase b (pkb/akt) kinases [103] . in contrast, amp-activated protein kinase (ampk) signal pathway is likely to mediate the effect of insulin-independent stimuli for glucose uptake in muscle [104] . in an in vitro study, myricetin enhanced akt and ampk protein activity, encouraged glucose uptake and reduced insulin resistance [105] . the mechanisms of myricetin for improving insulin-sensitive tissue might be the amelioration of impaired signaling intermediates downstream of insulin receptors through enhancing the secretion of β-endorphin, which in turn led to the activation of peripheral μ-opioid receptors [106, 107] . then, myricetin affects insulin receptor phosphorylation, insulin receptor substrate-1 (irs-1), the p85 regulatory subunit of pi3k, akt and akt substrate of 160 kd, with subsequent effects on glucose transporter 4 (glut4) translocation [108] . other previous studies on antidiabetic potential of the compound are shown in table 5 . cancer is responsible for second highest cause of death across the globe [124, 125] . it has been reported that number of death due to this devastating disease would expand to over 13 million by 2030 [126, 127] . laboratory and clinical studies have reported that myricetin from natural sources exerts promising effects against various types of cancer [19, 21] . the dietary compound myricetin also has the potential to inhibit key enzymes involved in cancer initiation and growth. myricetin has presented cytotoxic activity in human colon cancer cells. kim et al. [21] demonstrated that myricetin significantly induces the bcl2-associated x dose-dependent reduction in lithium-induced head twitches and anxiolytic activity by altering 5-hydroxytryptamine transmission. [80] in vitro pro-oxidant agent and reduced the formation of ordered amyloid beta (aβ)42 aggregation. [81] in silico destabilizes the β-sheet ordered amyloid oligomers formed by the undecapeptide aβ (25-35) model. [82] in vitro marked modulation of metal-induced aβ aggregation, more than metal-free aβ aggregation. increase cell survival rate of aβ (with metal ions). [83] in vitro increases α-secretase (adam10) enzyme activity and decreases of β-secretase (bace-1). it also exerts neuroprotective activity against aβ (1-42) with multifunctional role in counteracting ad progress. [84] in vitro dose-dependent inhibition of α-synuclein fibrils formation and destabilization (ec 50 = 0.21-1.8 μm). [85] in vitro dose-dependent inhibition of aβ fibrils formation from fresh aβ (1-40) and aβ . the ec 50 value for formation, extension and destabilization aβ fibrils ranges from 0.13-1.8 μm. [86] in vivo increases the number of hippocampal ca3 pyramidal neurons and survival in a rat model (10 mg/kg). improved learning and memory in a rat model with ad. [87] reduces the aggregation of different abnormal proteins and eliminates various toxic proteins related to neurodegenerative diseases. improves physiological functions of hsp70 molecular chaperone and reduces mis-folded proteins. [ 88] in vitro and in vivo increases gaba receptor activity via calcium channel/ camk-ii dependent mechanism, which is distinctively different from that of most existing benzodiazepine binding site agonists of gaba receptor. [89] in vivo increases mrna for brain-derived neurotrophic factor (bdnf) in the hippocampus of male c57bl/6 mice at 10 and 20 mg/ kg (7 days). [90] in vivo increases bdnf concentrations in the hippocampus of male c57bl/6 mice at 50 mg/kg (21 days). [91] in vivo enhances expression and activity of erk1/2-creb pathway and na + , k + -atpase while reduces oxidative stress level in hippocampus. improves learning and memory when compared with d-galactose. [92] in vivo reduces seizure severity and mortality rates in mouse models and signaling pathways (bdnf-trkb) and regulates gad65/ gaba with mmp-9 expression. [93] in vivo interacts with rna, especially cag motif, and decreases the huntingtin protein translation and sequestration. reduces cytotoxicity in hd and other polyq disease models. [94] in vitro suppresses intracellular ros production, re-establishes mitochondrial trans-membrane potential, and inhibits mkk4 and jnk activation. [ 95] in vitro and in vivo inhibits activation of microglia (neuroinflammation), expression of pro-inflammatory mediators and reduces the number of dopaminergic neurons. [96] in vivo dose-dependent delay in climbing ability loss, but increases the life span of flies expressing human α-synuclein in brain. [97] in vivo prevents the loss of dopaminergic neurons and dopamine content in brain of parkinson flies. [98] in vivo dose-dependent inhibitory activity on α-synuclein aggregation. [99] in vivo diminishes dopamine neuron degeneration, which is induced by 6-hydroxydopamine and 1-methyl-4-phenyl-pyridinium in substantia nigra-striatum. [100] aβ amyloid beta, cns central nervous system, bdnf brain-derived neurotrophic factor taheri this study suggested that myricetin can be utilized for the design of therapeutic agents against human colon cancer. myricetin also acts as a potent inhibitor of human flap endonuclease 1 (hfen1) protein (ic 50 690 nm), based on inhibitory mechanisms, molecular docking, and cancer cell-based assays [128] . the hfen1 protein is a functional member of the 5′-nuclease superfamily. by chemical nature, hfen1 is a metal iondependent and structure-specific nuclease and also instrumental in dna replication and repairing processes. molecular docking studies revealed that ring a of myricetin compound, including 4-keto and 5-oh, was found stretched towards the two divalent metal ions. both metal ions are critical as they seem to interact with arg100 and lys93 amino acids through hydrogen bonds. these interacted residues are well known for their critical interplay in hfen1's activity during human colon cancer. myricetin has also been shown to protect against ovarian cancer through suppressing ovarian cancer cell angiogenesis [129] . anti-angiogenic effects of myricetin (5 to 20 μm) assessed through in vitro (huvec) and in vivo (cam) models revealed that this compound significantly inhibits angiogenesis induced by ovcar-3 cells. in skov3 human ovarian cancer cells, myricetin inhibited viability and induced apoptosis (40 μg/ml, time-dependent manner) through endoplasmic reticulum stress and dna double-strand breaks [130] . zheng et al. [131] stated that in a2780 and ovcar3 ovarian cancer cells, the dietary flavonoid myricetin induced significant cytotoxicity (ic 50 = 25 μm). in a recent study, tavsan and kayali [132] reported that myricetin suppressed ovarian cancer cell growth, induced apoptosis, arrested cell cycle and also had the potential to inhibit cell invasion in a significant manner (ic 50 = 184 μm a2780, 32 μm ovcar-3, 3.3 μm skov3, and > 500 μm osf). thus, it can be concluded that myricetin has enough potential to cope with ovarian cancer in a significant manner. myricetin has potent anticancer-promoting activity against skin cancer. it was found capable of inhibiting neoplastic cell transformation and mitogen-activated protein kinase 1 (mek1) activity (myricetin 1 or 5 μm) [133] . molecular interaction between myricetin and mek1 suppressed mek1 activity leading to downstream signaling to the erk/p90rsk/ap-1 pathway. in another study, myricetin has been presented as a potent chemoprotective agent against skin cancer [134] . myricetin can bind directly to central kinases including pi3-k, akt, jak1, raf1, mek1, mkk4, and fyn, which regulate multiple cell signaling pathways in cancer cells. myricetin inhibited 12-o-tetradecanoylphorbol-13-acetate (tpa)and epidermal growth factor (egf)-induced cell transformation by 76 and 72%, respectively at 10 μm concentration. sun et al. [135] recently reported that myricetin has anticancer activity against skin cancer a431 cell lines, by inducing apoptosis and cell cycle arrest and exhibited low toxicity. an earlier in vitro study demonstrated the antimetastatic effect of myricetin in human lung adenocarcinoma a549 cells [136] . this study revealed that myricetin (5 to 20 μm) suppresses adenocarcinoma a549 cell invasion and migration through inhibition of the erk pathway in a time-dependent manner. along with a combination of radiotherapy, myricetin was found responsible to enhance the tumor radio-sensitivity of lung cancer a549 and h1299 cells through significant suppression of cell-surviving fraction and proliferation [137] . wang et al. [138] found that the combination of myricetin with 5-fluorouracil chemotherapy has the potential to enhance tumor chemo-sensitivity of esophageal cancer ec9706 cells. sun et al. [139] investigated the function of myricetin phytochemical against human t24 bladder cancer in a dose-and time-dependent fashion, and stated that myricetin significantly inhibits both t24 cancer cells viability and proliferation (ic 50 = 85 μm). the preclinical immunomodulatory effects of myricetin have also been increasingly reported. ghassemi-rad et al. [140] concluded that myricetin has the potential to inhibit t-lymphocyte activation in a mouse model through bead-immobilized anti-cd3 and anti-cd28 monoclonal antibodies. this study clarified the mechanism of action and reported the suppressive effect of myricetin on t lymphocytes mediated through extracellular h 2 o 2 generation. in mouse primary macrophages and raw264.7 monocytic cell-line, this phenolic compound was found to inhibit the lipopolysaccharide (lps)-induced interleukin (il)-12 production in a significant manner through down-regulation of nf-κb binding activity [22] . in isolated rat aortic rings, myricetin induced endothelium-dependent contractile responses at 50 μm. earlier, jiménez et al. [141] reported that, in cultured bovine endothelial cells, this compound is responsible for stimulating the production of cytosolic free calcium. in a myricetin in vivo enhanced enzymatic and non-enzymatic antioxidant defense system and showed protective effects against oxidative damage in liver and kidney of streptozotocin-cadmium-induced diabetic model. [109] myricetin in vivo inhibitory activity against α-glucosidase (ic 50 = 414 μm) in dose dependent manner. [110] myricetin in vivo anti-hyperglycemic and renoprotective effects at 1.0 mg/kg. [111] myricetin in vivo improved and re-established renal functions and activities of the glutathione peroxidase and xanthine oxidase enzymes in diabetic rat model. [112] myricetin in vivo antidiabetic activity against t-bhp-induced oxidative stress. [113] myricetin in vivo reduced glycemia in diabetic rats up to 50% after 2 days of treatment at 3 mg/12 h. [114] myricetin in vivo stimulated lipogenesis in rat adipocytes and enhanced the stimulatory effect of insulin (ec 50 = 65 μm). [115] myricetin in vitro inhibited intestinal α-glucosidase (29%) and porcine α-amylase (64%) with ic 50 vale of 0.38 mm. [116] abelmoschus moschatus medik. (aerial part) in vivo improved insulin sensitivity in rats. [117] ampelopsis grossedentata (hand.-mazz.) w.t. wang (leaves) in vivo inhibitory activity against α-glucosidase (ic 50 = 319.3 μm). [118] azadirachta indica a.juss. (leaves) in vivo enhanced insulin signaling pathway and glucose utilization in skeletal muscle. [119] hovenia dulcis thunb. (seeds) in vitro inhibited intestinal α-glucosidase with ic 50 = 3 μg/ml and α-amylase with ic 50 = 662 μg/ml. [120] myrtus communis l. (leaves) in vivo significant antidiabetic activity in diabetic models. [121] syzygium cumini (l.) skeels (seeds) in vitro inhibitory activity against α-glucosidase (ic 50 = 1.7 μg/ml) and α-amylase (ic 50 = 7.62 μg/ml). dose-dependent manner, myricetin inhibited the secretion of a potent t cell growth factor, namely il-2 protein from mouse el-4 t cells, activated with phorbol 12myristate 13-acetate (pma) plus ionomycin [142] . in vitro evidence demonstrated that at 5-100 μm, myricetin inhibits cd69 expression and lymphocytes proliferation in a mouse model. moreover, an in vitro investigation revealed that myricetin significantly effects il-2 expression. however, further in vitro and in vivo investigations are required to explore myricetin as an immunomodulatory agent. previous studies have demonstrated that myricetin also has beneficial effects on the human vascular system [23] . in human umbilical vein endothelial cells, myricetin (100 μm), revealed vasculoprotective effects through changes at the transcriptional level [143] . myricetin has been presented as a functional agent towards preventing atherosclerosis through inhibition of cd36 cell surface protein and mrna expression in a significant manner [144] . in isolated and langendorff-perfused rat hearts, without affecting contractility and relaxation, myricetin elicited coronary dilation [145] . in triton-treated hyperlipidemic rats, evidence from an in vivo investigation demonstrated that myricetin exerts lipid-lowering activity and suggests that myricetin can be utilized in the treatment of hyperlipidemia and cardiovascular diseases (cvd) [146] . in wistar rats, myricetin significantly inhibited the effects of histopathological changes of isoproterenol on heart rate, the levels of different cardiac marker enzymes, including lactate dehydrogenase (ldh), creatine kinase (ck), aspartate aminotransferase (ast), superoxide dismutase (sod) and catalase (cat), as well changes in vascular reactivity and electrocardiographic patterns [147] . a mechanism-based study by scarabelli et al. [148] demonstrated that myricetin exerts strong inhibitory activity against signal transducer and activator of transcription 1 (stat1) activation, and also protects the heart from ischemia/reperfusion-injury. the available genomic and genetics data from preclinical experiments have shown that myricetin is likely to confer the first line of defense against cardiovascular and other associated diseases. in acetic acid-induced writhing response, formalininduced paw licking, sedative activity and hot plate test models, myricetin revealed potent analgesic effects, closely related with peripheral analgesia, but not with the opioid system [24] . the compound also produced a significant analgesic effects in a rat model of neuropathic pain, by decreasing spinal nerve ligation-induced mechanical allodynia and thermal hyperalgesia lasting for several hours (0.1-10 mg/kg i.p.) [149] . the antihypertensive effects of myricetin were evaluated in the deoxycorticosterone acetate (doca)-salt-hypertensive rat model. myricetin reduced systolic blood pressure, vascular reactivity changes and reversed the increased heart rate induced by doca. at oral doses of 100 and 300 mg myricetin/kg b.w., the compound displayed antihypertensive propertie in the doca rat model of hypertension [25] . in another study, the compound lowered the high blood pressure that was induced by fructose doses of 100 and 300 mg/kg p.o. in rats and reversed sugar-triggered metabolic changes [150] . the wound-healing effects of myricetin-3-o-β-rhamnoside were investigated on three different types of cells, keratinocytes, fibroblasts, and endothelial cells. the compound exhibited significant wound healing activity at 10 μg/ml [151] . although the number of clinical studies reporting myricetin health benefits in ailments and disorders is low, the increasing data from preclinical studies have supported its beneficial effects [152, 153] . in a 4-week randomized placebo-controlled clinical trial the effect of 300 mg blueberin (250 mg blueberry leaves, vaccinium arctostaphylos l., and 50 mg myricetin, three times per day) on fasting plasma glucose and some other biochemical parameters has been investigated in 42 female volunteers (46 ± 15 years; body mass index, bmi, 25 ± 3 kg/m 2 ) with diabetes type 2. the blueberin treatment significantly reduced fasting plasma glucose from 143 ± 5.2 mg/l to 104 ± 5.7 mg/l. in addition to antidiabetic effects, results showed that blueberin also possessed pharmacologically relevant antiinflammatory properties, reduced plasma enzyme levels of alanine aminotransferases (alt), ast, glutamyltransferase (ggt), and reduced serum c-reactive proteins (crp) [154] . emulin™ (250 mg of patented blend of chlorogenic acid, myricetin, and quercetin), when regularly consumed, was able not only to lower the acute glycemic impact of foods, but also to chronically decrease blood glucose levels in type 2 diabetic humans (reductions between 1 and 5%) [155] . this study was performed in 40 male and female with fasting glucose range between 126 to 249 mg/ml and a bmi ≥ 30 kg/m 2 . data from different studies also indicate the importance of myricetin as a chemopreventive agent, acting on cell proliferation, signaling mechanisms, apoptosis, angiogenesis, and tumor metastasis [156] . through the analysis of habitual food consumption of 10,054 participants of finnish mobile clinic health examination survey developed during 1966-1972, knekt et al. [157] estimated that higher myricetin intakes in men led to lower prostate cancer risk. in a prospective study, gates et al. [158] analyzed the association between the 5 common dietary flavonoids (myricetin, kaempferol, quercetin, luteolin and apigenin) intake and epithelial ovarian cancer incidence in 66 [158] . the association between flavonoids and flavonoid-rich foods intake and exocrine pancreatic cancer development within the α-tocopherol, β-carotene cancer prevention study cohort were also examined [159] . of the 27,111 male smokers with 306 pancreatic cancers, the data obtained suggests that a flavonoid-rich diet may decrease pancreatic cancer risk in male smokers not consuming supplemental α-tocopherol and/ or β-carotene. tang et al. [160] showed that high/increased flavonoids (e.g., myricetin) intake is associated with lower lung cancer risk in their studied population (meta-analysis of 8 prospective studies and 4 casecontrol studies involving 5073 lung cancer cases and 237,981 non-cases). the intake of 36 g lyophilized grape powder (rich in flavans, anthocyanins, quercetin, myricetin, kaempferol, and resveratrol) also had a great impact in key risk factors for coronary heart disease (lowered levels of triglyceride, lowdensity lipoproteins, apolipoproteins b and e) in both preand post-menopausal women [161] . the study was performed on 24 pre-and 20 post-menopausal women for 4 weeks. however, wide ranges of clinical studies are still needed on the potential activities of myricetin which have been already indicated through in vitro and in vivo experiments. myricetin is a flavonoid present in many foods that has shown biological activities in numerous studies and has a potential use as a nutraceutical. its antimicrobial and antioxidant role is widely studied, and numerous studies have shown neurobiological activities and a potential beneficial impact on ad, pd, hd and als. also, preclinical studies have revealed antidiabetic, anticancer, immunomodulatory, anti-cardiovascular, analgesic and antihypertensive activities. these studies investigated the effect of myricetin, pure compound or plant extract rich in this compound. in plant studies, the extracts rich in myricetin always have other flavonoids that have also shown antioxidant activity alone. nevertheless, new well-designed studies have to be performed to study all of the biological effects described before, as well as preclinical studies comparing the effect of myricetin compared to other flavonoids and phytochemicals. in the case of neurological diseases, more in-depth studies have to be designed to show the pre-clinical results. chapter 10 -metabolic responses of plants upon different plant-pathogen interactions kaempferol: a key emphasis to its anticancer potential in vitro and in vivo assessment of free radical scavenging and antioxidant activities of veronica persica poir nomenclature of flavonoids (iupac recommendations 2017) preformulation studies of myricetin: a natural antioxidant flavonoid myricetin: biological activity related to human health myricetin-mediated lifespan extension in caenorhabditis elegans is modulated by daf-16 exploration of pro-oxidant and antioxidant activities of the flavonoid myricetin flavonols (kaempeferol, quercetin, myricetin) contents of selected fruits, vegetables and medicinal plants phenolic acid and flavonol contents of gemmo-modified and native extracts of some indigenous medicinal plants total phenolic compounds, flavonoids, and radical scavenging activity of 21 selected tropical plants content of the flavonols quercetin, myricetin, and kaempferol in 25 edible berries determination of myricetin in medicinal plants by highperformance liquid chromatography antioxidant constituents of three selected red and green color amaranthus leafy vegetable characterization of bioactive compounds and antioxidant activity of fruit beers estimation of daily human intake of food flavonoids estimation of dietary flavonoid intake and major food sources of korean adults flavonoid intake in european adults (18 to 64 years) myricetin: a dietary molecule with diverse biological activities myricetin attenuated diabetes-associated kidney injuries and dysfunction via regulating nuclear factor (erythroid derived 2)-like 2 and nuclear factor-κb signaling myricetin induces cell death of human colon cancer cells via bax/bcl2-dependent pathway inhibition of interleukin-12 production in mouse macrophagesvia decreased nuclear factor-κb dna binding activity by myricetin, a naturally occurring flavonoid polyphenols: potential use in the prevention and treatment of cardiovascular diseases analgesic activity of myricetin isolated from myrica rubra sieb effect of myricetin on deoxycorticosterone acetate (doca)-salt-hypertensive rats antiproliferative activity of pteleopsis suberosa leaf extract and its flavonoid components in human prostate carcinoma cells two new flavonoid glycosides from the halophyte limonium franchetii flavonoids from comptonia peregrina the diarylheptanoid (+)-ar,11s-myricanol and two flavones from bayberry (myrica cerifera) destabilize the microtubule-associated protein tau polyphenols from aerial parts of polygonum bellardii and their biological activities flavonoids in the leaves of twentyeight polygonaceous plants flavonoids and phenolic acids from labisia pumila (kacip fatimah) dietary flavonoids: bioavailability, metabolic effects, and safety department of agriculture (usda) food database flavonol content varies among black currant cultivars flavonoids in monospecific eucalyptus honeys from australia wine and grape polyphenols -a chemical perspective syringetin, a flavonoid derivative in grape and wine, induces human osteoblast differentiation through bone morphogenetic protein-2/extracellular signal-regulated kinase 1/2 pathway comprehensive review of antimicrobial activities of plant flavonoids phytochemicals in helicobacter pylori infections: what are we doing now? structure-activity relationship of flavonoids on their anti-escherichia coli activity and inhibition of dna gyrase myricetin inhibits escherichia coli dnab helicase but not primase differential inhibitory effects of various flavonoids on the activities of reverse transcriptase and cellular dna and rna polymerases antimicrobial efficacy of plant phenolic compounds against salmonella and escherichia coli novel strategy for biofilm inhibition by using small molecules targeting molecular chaperone dnak anti-hiv-1 activity of flavonoid myricetin on hiv-1 infection in a dual-chamber in vitro model screening of flavonoids for antitubercular activity and their structure-activity relationships identification of myricetin and scutellarein as novel chemical inhibitors of the sars coronavirus helicase, nsp13 antibacterial phenolics from the mangrove lumnitzera racemosa anti-oxidative and antibacterial constituents from sedum hybridum molecular docking and screening studies of new natural sortase a inhibitors activity and interactions of antibiotic and phytochemical combinations against pseudomonas aeruginosa in vitro inhibitory effects of flavonoids on moloney murine leukemia virus reverse transcriptase activity compounds from syzygium aromaticum possessing growth inhibitory activity against oral pathogens activity of plant flavonoids against antibiotic-resistant bacteria antibacterial activity directed isolation of compounds from punica granatum flavonols inhibit sortases and sortasemediated staphylococcus aureus clumping to fibrinogen structure elucidation, conformational analysis and thermal effects on membrane bilayers of an antimicrobial myricetin ether derivative antimicrobial activity of antibiotics in combination with natural flavonoids against clinical extended-spectrum β-lactamase (esbl)-producing klebsiella pneumoniae inhibitory effect of dietary phenolic compounds on chlamydia pneumoniae in cell cultures ultra-small micelles based on polyoxyl 15 hydroxystearate for ocular delivery of myricetin: optimization, in vitro, and in vivo evaluation antioxidant activity of polyphenolic myricetin in vitro cell-free and cell-based systems rosmarinic and carnosic acids as superior natural antioxidant alternatives to α-tocopherol for the preservation of omega-3 oils antioxidant behavior of mearnsetin and myricetin flavonoid compounds-a dft study microarray and pathway analysis highlight nrf2/are-mediated expression profiling by polyphenolic myricetin development of a myricetin/ hydroxypropyl-β-cyclodextrin inclusion complex: preparation, characterization, and evaluation antiinflammatory and antioxidant activities of some extracts and pure natural products isolated from rhus tripartitum (ucria) ferric reducing and radical scavenging activities of selected important polyphenols present in foods antioxidant capacity and vasodilatory properties of mediterranean food: the case of cannonau wine, myrtle berries liqueur and strawberry-tree honey structural elucidation and antioxidant activities of proanthocyanidins from chinese bayberry (myrica rubra sieb. et zucc.) leaves activity-guided isolation of antioxidant principles from limoniastrum feei (girard) batt effect of myricetin, pyrogallol, and phloroglucinol on yeast resistance to oxidative stress myricetin suppresses oxidative stress-induced cell damage via both direct and indirect antioxidant action nitric oxide scavenging rates of solubilized resveratrol and flavonoids myricetin affords protection against peroxynitrite-mediated dna damage and hydroxyl radical formation comparative study on antioxidant capacity of flavonoids and their inhibitory effects on oleic acid-induced hepatic steatosis in vitro myricetin protects cells against oxidative stress-induced apoptosis via regulation of pi3k/akt and mapk signaling pathways protective effect of flavonoids against reactive oxygen species production in sickle cell anemia patients treated with hydroxyurea the neuroprotective potential of flavonoids: a multiplicity of effects effect of myricetin on behavioral paradigms of anxiety disclosure of a fundamental clue for the elucidation of the myricetin mechanism of action as amyloid aggregation inhibitor by mass spectrometry amyloid beta-peptide 25-35 selfassembly and its inhibition: a model undecapeptide system to gain atomistic and secondary structure details of the alzheimer's disease process and treatment myricetin: a naturally occurring regulator of metal-induced amyloid-β aggregation and neurotoxicity multifunction of myricetin on aβ: neuroprotection via a conformational change of aβ and reduction of aβ via the interference of secretases antioxidant compounds have potent anti-fibrillogenic and fibril-destabilizing effects for α-synuclein fibrils in vitro potent anti-amyloidogenic and fibril-destabilizing effects of polyphenols in vitro: implications for the prevention and therapeutics of alzheimer's disease myricetin protects hippocampal ca3 pyramidal neurons and improves learning and memory impairments in rats with alzheimer's disease polyphenolic flavonoid (myricetin) upregulated proteasomal degradation mechanisms: eliminates neurodegenerative proteins aggregation flavonoid myricetin modulates receptor activity through activation of channels and camk-ii pathway dihydromyricetin exerts a rapid antidepressant-like effect in association with enhancement of bdnf expression and inhibition of neuroinflammation myricetin attenuates depressant-like behavior in mice subjected to repeated restraint stress in vivo investigation on the potential of galangin, kaempferol and myricetin for protection of d-galactose-induced cognitive impairment myricetin attenuates the severity of seizures and neuroapoptosis in pentylenetetrazole kindled mice by regulating the of bdnf-trkb signaling pathway and modulating matrix metalloproteinase-9 and gabaa myricetin reduces toxic level of cag repeats rna in huntington's disease (hd) and spino cerebellar ataxia (scas) myricetin attenuated mpp+-induced cytotoxicity by anti-oxidation and inhibition of mkk4 and jnk activation in mes23. 5 cells myricetin prevents dopaminergic neurons from undergoing neuroinflammation-mediated degeneration in a lipopolysaccharide-induced parkinson's disease model effect of myricetin on the transgenic drosophila model of parkinson's disease effect of myricetin on the loss of dopaminergic neurons in the transgenic drosophila model of parkinson's disease inhibition and disaggregation of α-synuclein oligomers by natural polyphenolic compounds myricetin reduces 6-hydroxydopamine-induced dopamine neuron degeneration in rats myricetin protects against high glucose-induced β-cell apoptosis by attenuating endoplasmic reticulum stress via inactivation of cyclin-dependent kinase 5 myricetin: a potent approach for the treatment of type 2 diabetes as a natural class b gpcr agonist insulin signalling and the regulation of glucose and lipid metabolism ampactivated protein kinase and muscle insulin resistance. front biosci (landmark ed) myricetin attenuates hyperinsulinemia-induced insulin resistance in skeletal muscle cells myricetin ameliorates defective post-receptor insulin signaling via β-endorphin signaling in the skeletal muscles of fructose-fed rats minireview: therapeutic potential of myricetin in diabetes mellitus myricetin ameliorates defective post-receptor insulin signaling via beta-endorphin signaling in the skeletal muscles of fructose-fed rats myricetin modulates streptozotocincadmium induced oxidative stress in long term experimental diabetic nephrotoxic rats α-glucosidase inhibitory activities of myricetin in animal models of diabetes mellitus myricetin, a natural flavonoid, normalizes hyperglycemia in streptozotocin-cadmium-induced experimental diabetic nephrotoxic rats beneficial effect of myricetin on renal functions in streptozotocin-induced diabetes myricetin may provide protection against oxidative stress in type 2 diabetic erythrocytes effects of myricetin on glycemia and glycogen metabolism in diabetic rats insulinomimetic effects of myricetin on lipogenesis and glucose transport in rat adipocytes but not glucose transporter translocation inhibition of α-glucosidase and α-amylase by flavonoids improvement of insulin sensitivity in obese zucker rats by myricetin extracted from abelmoschus moschatus α-glucosidase inhibition and antihyperglycemic activity of flavonoids from ampelopsis grossedentata and the flavonoid derivatives molecular approach to identify antidiabetic potential of azadirachta indica evaluation of total flavonoids, myricetin, and quercetin from hovenia dulcis thunb. as inhibitors of α-amylase and α-glucosidase biochemical studies on the effect of phenolic compounds extracted from myrtus communis in diabetic rats syzygium cumini seed exhibits antidiabetic potential via multiple pathways involving inhibition of αglucosidase, dpp-iv, glycation, and ameliorating glucose uptake in l6 cell lines potential antihyperglycaemic effect of myricetin derivatives from syzygium malaccense assessment, origin, and implementation of breath volatile cancer markers vocc: a database of volatile organic compounds in cancer age and cancer risk: a potentially modifiable relationship programmed cell death, from a cancer perspective: an overview discovery of myricetin as a potent inhibitor of human flap endonuclease 1, which potentially can be used as sensitizing agent against ht-29 human colon cancer cells myricetin inhibits proliferation of cisplatin-resistant cancer cells through a p53-dependent apoptotic pathway myricetin induces apoptosis via endoplasmic reticulum stress and dna double-strand breaks in human ovarian cancer cells myricetin induces apoptosis and enhances chemosensitivity in ovarian cancer cells flavonoids showed anticancer effects on the ovarian cancer cells: involvement of reactive oxygen species, apoptosis, cell cycle and invasion myricetin is a novel natural inhibitor of neoplastic cell transformation and mek1 myricetin is a potent chemopreventive phytochemical in skin carcinogenesis myricetin exerts potent anticancer effects on human skin tumor cells myricetin suppresses invasion and migration of human lung adenocarcinoma a549 cells: possible mediation by blocking the erk signaling pathway enhancement of recombinant myricetin on the radiosensitivity of lung cancer a549 and h1299 cells myricetin enhance chemosensitivity of 5-fluorouracil on esophageal carcinoma in vitro and in vivo potential anticancer activity of myricetin in human t24 bladder cancer cells both in vitro and in vivo myricetin-induced oxidative stress suppresses murine t lymphocyte activation involvement of thromboxane a2 in the endothelium-dependent contractions induced by myricetin in rat isolated aorta inhibition of interleukin-2 production by myricetin in mouse el-4 t cells gene expression profiling of human umbilical vein endothelial cells exposed to myricetin morin and myricetin attenuate cd36 expression and oxldl uptake in u937-derived macrophages distinct signalling mechanisms are involved in the dissimilar myocardial and coronary effects elicited by quercetin and myricetin, two red wine flavonols lipid lowering and antioxidant activity of flavones in triton treated hyperlipidemic rats cardioprotective potential of myricetin in isoproterenol-induced myocardial infarction in wistar rats targeting stat1 by myricetin and delphinidin provides efficient protection of the heart from ischemia/reperfusion-induced injury antiallodynic effect of the flavonoid myricetin in a rat model of neuropathic pain: involvement of p38 and protein kinase c mediated modulation of ca2+ channels effect of myricetin on blood pressure and metabolic alterations in fructose hypertensive rats wound healing potential of chlorogenic acid and myricetin-3-o-β-rhamnoside isolated from parrotia persica protective functions of myricetin in lps-induced cardiomyocytes h9c2 cells injury by regulation of malat1 development of m10, myricetin-3-o-beta-d-lactose sodium salt, a derivative of myricetin as a potent agent of anti-chronic colonic inflammation effect of blueberin on fasting glucose, c-reactive protein and plasma aminotransferases, in female volunteers with diabetes type 2: double-blind, placebo controlled clinical study effect of emulin on blood glucose in type 2 diabetics molecular mechanisms underlying anticancer effects of myricetin flavonoid intake and risk of chronic diseases a prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer flavonoid intake and risk of pancreatic cancer in male smokers (finland) flavonoids intake and risk of lung cancer: a meta-analysis grape polyphenols exert a cardioprotective effect in preand postmenopausal women by lowering plasma lipids and reducing oxidative stress publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-269943-g77qe5ml authors: di sotto, antonella; vitalone, annabella; di giacomo, silvia title: plant-derived nutraceuticals and immune system modulation: an evidence-based overview date: 2020-08-22 journal: vaccines (basel) doi: 10.3390/vaccines8030468 sha: doc_id: 269943 cord_uid: g77qe5ml immunomodulators are agents able to affect the immune system, by boosting the immune defences to improve the body reaction against infectious or exogenous injuries, or suppressing the abnormal immune response occurring in immune disorders. moreover, immunoadjuvants can support immune system acting on nonimmune targets, thus improving the immune response. the modulation of inflammatory pathways and microbiome can also contribute to control the immune function. some plant-based nutraceuticals have been studied as possible immunomodulating agents due to their multiple and pleiotropic effects. being usually more tolerable than pharmacological treatments, their adjuvant contribution is approached as a desirable nutraceutical strategy. in the present review, the up to date knowledge about the immunomodulating properties of polysaccharides, fatty acids and labdane diterpenes have been analyzed, in order to give scientific basic and clinical evidence to support their practical use. since promising evidence in preclinical studies, limited and sometimes confusing results have been highlighted in clinical trials, likely due to low methodological quality and lacking standardization. more investigations of high quality and specificity are required to describe in depth the usefulness of these plant-derived nutraceuticals in the immune system modulation, for health promoting and disease preventing purposes. immunomodulators are defined as agents able to affect the immune response, which represents the set of reactions activated to protect the organism against infective agents, environmental injuries and illness; moreover, immune response can counteract the invasion of harmful native cells, such as precancerous and cancerous ones [1] . immune response is mediated by a first line of defence, namely innate immunity (figure 1 ), which is characterized by physical and biochemical barriers, alongside a non-specific cell-mediated immune response, including granulocytes, macrophages, natural killer cells and humoral elements, which cooperate to counteract pathogen infection and malignant transformation [2] . moreover, an adaptive immunity is activated as a second defense line after a macrophage-mediated presentation of antigens to b lymphocytes, with the help of t lymphocytes; then, b cells can mediate the humoral immunity through the production of high-affinity antibodies and establish immunological memory [3] . moreover, t lymphocytes can mediate cellular immunity after activation by cytokines released from helper t cells [2] . responses involved in innate and adaptive immunity. fast and nonspecific responses, occurring against all factor identified as nonself, are involved in innate immunity; conversely, adaptive immunity is a highly specific, complex and slow response mediated by t and b lymphocytes, which release antigen-specific antibodies and cytokines. immunomodulators can directly affect innate and adaptive response or the factors involved, thus leading to immunostimulant or immunosuppressive effects. a further group of immunomodulators is represented by immunoadjuvants, able to enhance immune response to vaccines without producing specific antigenic effects, and more recently approached as adjuvant pharmacological treatments, especially for viral infections and cancers [8] [9] [10] [11] [12] . immune-associated disorders, including autoimmune diseases, viral or bacterial infections, and chronic diseases, are usually associated with acute inflammation, which represents a key component for the activation of immune response [13] . on the other hand, the chronicity of inflammatory response can negatively influence the immune function, affecting both innate immune cells and t and b lymphocytes, thus suggesting a possible usefulness of anti-inflammatory immunomodulators [13] . accordingly, immunomodulatory agents, with antioxidant and anti-inflammatory activity, have attracted great attention as possible chemopreventive agents, due to their ability to counteract chronic inflammation, which provides favorable conditions for the transition from normal to cancer cell [14] . responses involved in innate and adaptive immunity. fast and nonspecific responses, occurring against all factor identified as nonself, are involved in innate immunity; conversely, adaptive immunity is a highly specific, complex and slow response mediated by t and b lymphocytes, which release antigen-specific antibodies and cytokines. immunomodulators can directly affect innate and adaptive response or the factors involved, thus leading to immunostimulant or immunosuppressive effects. immunomodulating agents can affect immunity in a negative or positive manner, thus being categorized as suppressing or stimulant [4] . particularly, immunosuppressors inhibit the activation of immune response or decrease the activity of its components, thus restoring normalcy. they are of interest in organ transplantations and in autoimmune disorders, wherein the immune system mistakenly activates an immune response against the own body tissues, leading to their destruction [4] . for instance, vitamin d has been shown to counteract the aberrant immune responses of systemic lupus erythematosus, without compromising the physiological defences and to produce benefits in atopic dermatitis too [5, 6] . conversely, immunostimulants boost the endogenous immune defences, thus allowing one to restore or maintain the body homeostasis [4] . they can be usefully exploited as immunotherapeutic agents by individuals with immunocompromised conditions; however, they can represent suitable prophylactic strategies for healthy individuals or more susceptible subjects against viral infections [4] . in support, during the current sars-cov-2 pandemic, the trained immunity by vaccines, which induce heterologous protection, have been proposed as a rational strategy to boost antiviral defences and reduce susceptibility to infection [7] . a further group of immunomodulators is represented by immunoadjuvants, able to enhance immune response to vaccines without producing specific antigenic effects, and more recently approached as adjuvant pharmacological treatments, especially for viral infections and cancers [8] [9] [10] [11] [12] . immune-associated disorders, including autoimmune diseases, viral or bacterial infections, and chronic diseases, are usually associated with acute inflammation, which represents a key component for the activation of immune response [13] . on the other hand, the chronicity of inflammatory response can negatively influence the immune function, affecting both innate immune cells and t and b lymphocytes, thus suggesting a possible usefulness of anti-inflammatory immunomodulators [13] . accordingly, immunomodulatory agents, with antioxidant and anti-inflammatory activity, have attracted great attention as possible chemopreventive agents, due to their ability to counteract chronic inflammation, which provides favorable conditions for the transition from normal to cancer cell [14] . furthermore, immunostimulants can act as adjuvant anticancer treatments, to counteract their immunosuppressive side-effects [14] . particularly, aristolochic acid, an alkaloid from aristolochia clematitis l., showed immunostimulatory properties, by enhancing the phagocytic activity of peritoneal macrophages and leukocytes; however, its potential cannot be exploited, because of its carcinogenic risk [50] . likewise, vincristine and staurosporine act as immunostimulants at low doses, while as immunosuppressors particularly, aristolochic acid, an alkaloid from aristolochia clematitis l., showed immunostimulatory properties, by enhancing the phagocytic activity of peritoneal macrophages and leukocytes; however, its potential cannot be exploited, because of its carcinogenic risk [50] . likewise, vincristine and staurosporine act as immunostimulants at low doses, while as immunosuppressors at higher doses [51] . among polyphenols, resveratrol stimulated both cellular and humoral immunity in preclinical models, thus preventing pathogen replication and inflammation, and promoted antitumor immune response too [52] . furthermore, cichoric acid from echinacea promoted phagocytic activity, both in vitro and in vivo [53] . anti-inflammatory and immune-modulatory effects has been highlighted for curcumin too, although the poor bioavailability limits its clinical application [54] . in the present review, up to date knowledge on the scientific basis for the immunomodulatory activity and clinical relevance of some emerging classes of plant-derived nutraceuticals, including polysaccharides, fatty acids and labdane diterpenes, has been reported. a comprehensive search was made using pubmed and scopus electronic databases and selecting english as the preferred language, although no language limitations nor filters were applied. for more specific requirements, google scholar and clinicaltrials.gov were considered too. the following searching keywords and their combinations through the boolean logical operators were used: "herbal immunomodulators", "phytochemicals", "immune system", "nutraceuticals", "medicinal plants", "immunomodulation", "immune system boosters", "immunosuppressors", "immunoadjuvants", "gut microbiome", "natural occurrence", "chemical features", "preclinical studies", "clinical trials", "polysaccharides", "echinacea", "astragalus", "β-glucan", "fatty acids", "pufa", "oleic acid", "punicic acid", "γ-linolenic acid", "linoleic acid", "evening primrose oil", "borage oil", "flaxseed oils", "labdane diterpenes" and "andrographolide". this overview allows one to identify novel immune system modulators to be usefully exploited for health promoting and disease preventing purposes. polysaccharides are carbohydrate macromolecules containing at least 10 monosaccharide units, joined by glycosidic linkages to form long-chain molecules, which can be both linear and highly branched. they are called homopolysaccharides when constituted of the same monosaccharide unit, while heteropolysaccharides if different units are present. some of them are also referred to as dietary fibres, meaning that these macromolecules are neither digested nor absorbed in the human small intestine [55] . several polysaccharides have been found to modulate both innate and adaptive immune responses, among which, glucans, mannans, pectins, fucoidans, galactans, fructans, and xylans are the most studied ( figure 3 ) [56] . chemical structure, molecular weight, conformation, the presence of functional groups (i.e., acetyl and sulfate groups), and branching have been identified as structural features for the immunostimulatory properties of polysaccharides. the chemical structures of the polysaccharides associated with immunomodulatory properties are displayed in figure 4 . glucans are based on the d-glucopyranosyl unit (homoglucans); the different glycosidic bonds, namely (β1→4), (β1→3), and (β 1→6) or (α1→3), (α 1→4), and (α 1→6), allow the production of linear and branched glucans. it seems that (β1→3)-d-glucan moiety, triple helix conformations, sulfation and carboxymethylation of (β 1→3)-d-glucans, and chain acetylation are involved in glucan immunostimulatory activity. regarding (α1→6) (α1→4)-d-glucans, their structure activity relationship is less characterized [56] . while heteropolysaccharides if different units are present. some of them are also referred to as dietary fibres, meaning that these macromolecules are neither digested nor absorbed in the human small intestine [55] . several polysaccharides have been found to modulate both innate and adaptive immune responses, among which, glucans, mannans, pectins, fucoidans, galactans, fructans, and xylans are the most studied ( figure 3 ) [56] . chemical structure, molecular weight, conformation, the presence of functional groups (i.e., acetyl and sulfate groups), and branching have been identified as structural features for the immunostimulatory properties of polysaccharides. the chemical structures of the polysaccharides associated with immunomodulatory properties are displayed in figure 4 . glucans are based on the d-glucopyranosyl unit (homoglucans); the different glycosidic bonds, namely (β1→4), (β1→3), and (β 1→6) or (α1→3), (α 1→4), and (α 1→6), allow the production of linear and branched glucans. it seems that (β1→3)-d-glucan moiety, triple helix conformations, sulfation and carboxymethylation of (β 1 → 3)-d-glucans, and chain acetylation are involved in glucan immunostimulatory activity. regarding (α1 → 6) (α1 → 4)-d-glucans, their structure activity relationship is less characterized [56] . mannans consist of a d-mannose backbone, linked mainly by β1→4 bonds, which can be ramified with other monosaccharide, so originating glucomannan, galactomannan, and galactoglucomannan [57] . furthermore, (β1→3)-or (α1→3)-, (β1→2)-, and (β1→6)-or (α1→6)-dmannosidic bonds are reported [56] . the (β1→6)-d-mannan moiety (e.g., galctoglucomannans), acetyl and sulfate group presence, and this kind of branching seems to confer a high immunostimulatory activity [58] [59] [60] . pectins are complex polysaccharides which contain a common galactopyranosyluronic acid. homogalacturonans, xylogalacturonan, apiogalacturonan, rhamnogalacturonan, type i and ii arabinogalactans belong to this class. particularly, type i arabinogalactans (ag-i) possess an α-1arabinofuranosyl and β-d-galactopyranosyl units linked via position 3 at the main chain, while type ii arabinogalactans (ag-ii) comprise highly branched polysaccharides with ramified chains of (β1→ 3)-and (β1→6)-d-galactopyranosyl units [61, 62] , to which the arabinosyl units might be attached. the degree of branching, methyl esterification, acetylation, and the type of branched chains and mannans consist of a d-mannose backbone, linked mainly by β1→4 bonds, which can be ramified with other monosaccharide, so originating glucomannan, galactomannan, and galactoglucomannan [57] . furthermore, (β1→3)-or (α1→3)-, (β1→2)-, and (β1→6)-or (α1→6)-d-mannosidic bonds are reported [56] . the (β1→6)-d-mannan moiety (e.g., galctoglucomannans), acetyl and sulfate group presence, and this kind of branching seems to confer a high immunostimulatory activity [58] [59] [60] . pectins are complex polysaccharides which contain a common galactopyranosyluronic acid. homogalacturonans, xylogalacturonan, apiogalacturonan, rhamnogalacturonan, type i and ii arabinogalactans belong to this class. particularly, type i arabinogalactans (ag-i) possess an α-1-arabinofuranosyl and β-d-galactopyranosyl units linked via position 3 at the main chain, while type ii arabinogalactans (ag-ii) comprise highly branched polysaccharides with ramified chains of (β1→3)-and (β1→6)-d-galactopyranosyl units [61, 62] , to which the arabinosyl units might be attached. the degree of branching, methyl esterification, acetylation, and the type of branched chains and molecular weight determine the structural diversity [63] . moreover, flexible chain conformation and branched regions are the main ones responsible for the immunomodulatory properties [64, 65] . galactans are polysaccharides rich in galactose and include, beside type i and ii arabinogalactans, carrageenans, chemically characterized by repeating disaccharide units of sulfated or unsulfated d-galactose, that are linked by (β1→4)-and (α1→3)-bonds. low molecular weight (<20 kda) and a high degree of sulfation have been reported as features that high influence their immunomodulatory properties [66, 67] . fucoidans are heteropolysaccharides rich in l-fucopyranosyl sulfated units linked by (α1→2), (α1→3) or (α1→4) bonds. other monosaccharides can be present, such as galactopyranosyl, mannopyranosyl, xylosepyranosyl and uronic acids [68] . the naturally higher content of sulfate groups and the presence of acetyl groups are associated with a higher stimulatory activity [56] . fructans are polysaccharides which constitute up to 70 fructose units with a sucrolose terminal molecule. they are classified in inulin with a (β2→1)-d-fructofuranosyl, levan with a (β2→6)-d-fructofuranosyl, and mixed type, with both (β2→1)-and (β2→6)-linked d-fructofuranosyl moieties. a helical conformation has been associated with the modulatory activity on the immune system [69, 70] . at last, xylans are polysaccharides containing predominantly a backbone of (β1→4)-dxylosepyranosyl units. other monomers attached to their backbone include α-dglucopyranosyl a units (glucuronoxylans) and α-l-arabinofuranosyl units (arabinoxylans). a correlation between their structure and activity has not been elucidated yet [71, 72] . polysaccharides are naturally occuring in animal body fluids, cell walls, bacteria, yeast and fungi, extra cellular fluids, and in plant seeds, stems and leaves, which represent the focus of the present review. the main advantage of plant polysaccharides seems to be the low toxicity with respect to immunomodulatory bacterial polysaccharides and synthetic compounds [73] . thus, they represent an ideal alternative for immune modulation. a variety of polysaccharides with immunomodulatory properties have been discovered in different species of plants (table 2 ). among the most studied, there are type i and ii arabinogalactans from astragalus membranaceus (fisch.) bge., fructans from allium sativum l. [56] , fucogalactoxyloglucan and type ii acidic arabinogalactan from echinacea purpurea l. (moench), ginsan and panaxanes from panax ginseng c.a. meyer, acemannan and aloeride from aloe vera l. [74] , and glucomannan from amorphallus konjac koch [75] . several studies have shown that polysaccharides from plants can modulate both innate and acquired intestinal immunity, by direct and indirect mechanisms. the former include the activation of immune cells (e.g., macrophages, dendritic cells, natural killer cells, t cells, b lymphocytes), while the latter the short-chain fatty acid (scfa) formation ( figure 5 ). of immune cells (e.g., macrophages, dendritic cells, natural killer cells, t cells, b lymphocytes), while the latter the short-chain fatty acid (scfa) formation ( figure 5 ). the immunomodulatory effects of plant polysaccharides on macrophages are mainly achieved through the generation of reactive oxygen and nitrogen species (ros and nos), and the stimulation of cytokines secretion, cell proliferation, and macrophage phagocytic activity [101] . for example, a. membranaceus polysaccharides have been shown to promote nitric oxide (no) synthesis in macrophages, by inducing the gene expression of inducible nitric oxide synthase (inos), through the activation of nuclear factor kappa-b (nf-κb)/rel [102, 103] . moreover, they were also able to increase the macrophage phagocytic activity, by enhancing their secretion of release factor and intracellular ca 2+ concentration [104, 105] . pectic polysaccharides from citrus unshiu marc. have been shown to simultaneously regulate the expression of pro-and anti-inflammatory cytokines. particularly, they increased the production of the pro-inflammatory cytokines tumor necrosis factor (tnf)-α and interleukin (il)-6 and the antiinflammatory cytokine il-12 in macrophage raw264.7, so showing a regulatory mechanism to maintain an equilibrium state [106] . arabinogalactan from e. purpurea has been reported to increase macrophages activation and il-1, tnf-α and interferon (ifn)-β production [86] . the activation of macrophages by plant polysaccharides seems to be due to specific receptors present on their surface, which initiates the immune response, and exerts an immunomodulatory effect. these receptors are called pattern recognition molecules, and include: toll-like receptor 4 (tlr4), cd14, complement receptor 3 (cr3), scavenger receptor (sr), mannose receptor (mr), and dectin-1. their activation determines a series of intracellular signaling cascades, leading to the transcriptional activation and production of inflammation-related cytokines [101] . immunity modulation by plant polysaccharides can be achieved also by modulating the cytokine release from intestinal dendritic cells. indeed, pectin has been shown to reduce il-6 and il-10 release induced by the synthetic lipopeptide p3csk4 [107] . moreover, inulin, pectin, arabinoxylan and β-glucan have been found to elevate il-10/il-12 ratio and to reduce the release of ifn-γ, il-12, il-1, il-6, il-8, monocyte chemoattractant protein (mcp)-1, macrophage inflammatory proteins the immunomodulatory effects of plant polysaccharides on macrophages are mainly achieved through the generation of reactive oxygen and nitrogen species (ros and nos), and the stimulation of cytokines secretion, cell proliferation, and macrophage phagocytic activity [101] . for example, a. membranaceus polysaccharides have been shown to promote nitric oxide (no) synthesis in macrophages, by inducing the gene expression of inducible nitric oxide synthase (inos), through the activation of nuclear factor kappa-b (nf-κb)/rel [102, 103] . moreover, they were also able to increase the macrophage phagocytic activity, by enhancing their secretion of release factor and intracellular ca 2+ concentration [104, 105] . pectic polysaccharides from citrus unshiu marc. have been shown to simultaneously regulate the expression of pro-and anti-inflammatory cytokines. particularly, they increased the production of the pro-inflammatory cytokines tumor necrosis factor (tnf)-α and interleukin (il)-6 and the anti-inflammatory cytokine il-12 in macrophage raw264.7, so showing a regulatory mechanism to maintain an equilibrium state [106] . arabinogalactan from e. purpurea has been reported to increase macrophages activation and il-1, tnf-α and interferon (ifn)-β production [86] . the activation of macrophages by plant polysaccharides seems to be due to specific receptors present on their surface, which initiates the immune response, and exerts an immunomodulatory effect. these receptors are called pattern recognition molecules, and include: toll-like receptor 4 (tlr4), cd14, complement receptor 3 (cr3), scavenger receptor (sr), mannose receptor (mr), and dectin-1. their activation determines a series of intracellular signaling cascades, leading to the transcriptional activation and production of inflammation-related cytokines [101] . immunity modulation by plant polysaccharides can be achieved also by modulating the cytokine release from intestinal dendritic cells. indeed, pectin has been shown to reduce il-6 and il-10 release induced by the synthetic lipopeptide p3csk4 [107] . moreover, inulin, pectin, arabinoxylan and β-glucan have been found to elevate il-10/il-12 ratio and to reduce the release of ifn-γ, il-12, il-1, il-6, il-8, monocyte chemoattractant protein (mcp)-1, macrophage inflammatory proteins (mip)-1α, rantes and tnf-α by dendritic cells [108] . polysaccharide enriched extracts of e. purpurea have been found to promote the phenotypic and functional maturation of dendritic cells by modulating c-jun n-terminal kinase (jnk), p38 mitogen-activated protein kinase (mapk) and nf-κb pathways [109] . the activation of natural killer (nk) cells also contributes to the immunity modulation by polysaccharides. indeed, it has been shown that a. membranaceus polysaccharides can enhance the activity and killing effects of nk cells and promote their proliferation in rats with gastric cancer [110] . moreover, they were able to increase cd3-cd4-cd8+ nks in peripheral blood lymphocytes [111] . nks activation is probably due to the polysaccharides interaction with the killer cell lectin-like receptor k1(klrk1) of nks [112] . arabinoxylans extracted from wheat bran have been shown to inhibit the growth of transplantable tumors, and to promote the nk cell activity in s180 tumor-bearing mice [113] . moreover, the mgn-3 rice bran arabinoxylan showed to enhance natural killer (nk) cell activity in aged c57bl/6 and c3h mice upon its intraperitoneal injection [114] . adaptive immunity is also modulated by plant polysaccharides. particularly, fan et al. have shown that polysaccharides from a. membranaceus significantly up-regulated the proliferation of b lymphocytes, probably through the interaction with immunoglobulin on the surface of b cells [115] [116] [117] . a. membranaceus polysaccharides were also able to increase the number of cd3+cd4+cd8+ memory t helper (th) cells and cd3+cd4-cd8+ cytotoxic t cells [111] . moreover, they also enhance the cd4+/cd8+ t cell ratio [118] . furthermore, arabinoxylan were found to increase the activation of tand b-cells and humoral and cell-mediated immunity in tumor bearing mice [71] . at last, β-glucan microparticles enhanced t-cell activation and proliferation in vitro [119] . their ability to affect the immune system by inducing th1 and/or th2 type immune response makes polysaccharides suitable adjuvants of the vaccine. among them, inulin, chitosan, glucans and mannans have been most extensively studied. particularly, the gamma and delta forms of inulin fructan have shown adjuvant activity against infectious pathogens by stimulating both th1 and th2 responses without inducing immunoglobulin e (ige) production [120] . moreover, advax, a polysaccharide derived from delta inulin, has demonstrated to increase the immunization derived from influenza vaccine in mice. particularly, an induction of neutralizing antibody and memory b-cell against influenza, an increase in cd4 and cd8 t-cell proliferation, and enhanced levels of il-2, ifn-γ, il-5, il-6 were highlighted [121] . advax also enhanced the immunogenicity of hepatitis b surface antigen (hbs) in mice and guinea pigs, by increasing both anti-hbs antibody titers and anti-hbs cd4 and cd8 t-cells. th1, th2 and th17 responses were increased too [122] . astragalus polysaccharides were also used as adjuvants of hepatitis b virus dna vaccine in a mice model, showing increased hbsag-specific antibody levels, higher activity of t cells, the production of il-4, il-2 and ifn-γ by cd4+ t cells, and ifn-γ expression of cd8+ t cells. moreover, a stimulation of cytotoxic lymphocytes and dendritic cells maturation, and a reduction in the frequency of regulatory t cells were observed [123] . mannans and fructooligosaccharide have also been shown to possess adjuvanticity [124, 125] . furthermore, indirect effects are involved in the immunomodulatory properties of polysaccharides. in particular, dietary fibers (e.g., inulin, mannan, β-glucan, pectin) are metabolized by intestinal bacteria in the anaerobic environment of the cecum and colon, so generating scfa, such as acetate, propionate and butyrate [126] . these molecules are able to cross the gut epithelium and interact with surface receptors on the immune cells, such as the g-protein coupled receptors (gprs) 41 and 43 [127] . the activation of gprs by scfa modulates inflammatory signalling pathways, such as nf-κb, erk and p38 mapk [128, 129] . moreover, it has been highlighted that scfa can reach t lymphocyte nucleus, so modulating several functions through a histone deacetylase (hdac) inhibition. recently, scfa have been reported able to induce t cells metabolic alterations by enhancing the mtor complex activity. particularly, after absorption into t cells, scfa can stimulate the activity of mtor complex, so increasing the conversion of pyruvate into acetyl-coa. moreover, the acetyl groups from scfa can be link to coa and enter the tricarboxylic acid cycle. the increased levels of citrate are exported from mitochondria into the cytoplasm, where the enzyme atp citrate lyase converts it into acetyl-coa, then used by histone acetyltransferases (hats) for histone acetylation and the regulation of cytokine gene expression [126] . some clinical studies have been carried out on the potential immunomodulatory properties of polysaccharides, and a. membranaceus, e. purpurea and β-glucan have been most investigated. in a clinical trial on a. membranaceus by jiang et al. [130] , twenthy-eight stable continuous ambulatory peritoneal dialysis patients were treated with peritoneal dialysis fluid containing astragalus (20 ml/2 l) for one week. an increase in the macrophage phagocytic capacity, no and tnf-α contents were observed in patients compared to those before the treatment [130] . furthermore, ji et al. [131] investigated the effect of astragalus pre-operative treatment of colorectal cancer patients (n = 128) on immune function. results showed that astragalus pre-operative treatment promoted the nk cell activity in postoperative patients. in addition, the possible immunomodulatory activity of astragalus in patients with acute exacerbations of bronchial asthma (n = 72) has been investigated [132] . particularly, it was observed that the combination of conventional therapy with astragalus injection for 14 days improved the effects of routine treatment, by enhancing t lymphocyte and nk-cells immune function. results of clinical trials on the immune system modulation by e. purpurea are controversial. particularly, a randomized blinded trial carried out on 108 patients revealed that there was no significant difference in the incidence and severity of colds and respiratory infection between echinacea treatment (8 weeks) and placebo groups. however, a small decrease of total lymphocyte counts was observed [133] . another randomized, placebo controlled, double-blind clinical trial investigated the effect of different echinacea preparations, namely echinaforce ® (e. purpurea preparation from 95% herba and 5% radix), e. purpurea concentrate (same preparation at 7 times higher concentration), special e. purpurea radix preparation (totally different from that of echinaforce ® ) on the reduction of the complaint index, defined by 12 symptoms in healthy, adult volunteers who caught a common cold. the treatment continued until the enrolled patients felt healthy again, but not longer than 7 days. the supplementation with echinaforce ® and its concentrated preparation showed to be significantly more effective than the special echinacea extract or placebo. moreover, all treatments were well tolerated [134] . furthermore, prevention trials have been carried out, showing that echinacea products slightly reduce the risk of getting a cold in healthy individuals [135] . however, the heterogeneity (e.g., different species and part used) of preparations used in the trials makes the conclusions on the potential immunomodulatory properties of echinacea difficult. clinical trials concerning the β-glucan immunomodulatory properties have also been carried out, although in some cases, yeast-derived-glucan were used. particularly, three randomized, double-blind, placebo-controlled studies have evaluated the effects of short-term β-glucan supplementation on children with chronic respiratory problems. after 30 days' treatment, significant improvements in immunoglobulin, lysozyme, exhaled nitric oxide, and calprotectin production were found [136] [137] [138] . furthermore, the combination of resveratrol plus carboxymethyl-β-glucan as a solution for aerosol has been tested in clinical trials. particularly, the ability of the combination to prevent or treat recurrent respiratory infections in children was studied [139, 140] . in both cases, resveratrol plus carboxymethyl-β-glucan had a positive impact on children clinical conditions. indeed, nasal obstruction, rhinorrhea, sneezing, cough, fever, medication use, medical visits, and school absence were significantly reduced. moreover, resveratrol plus carboxymethyl-β-glucan have also been shown to relief nasal symptoms in children with allergic rhinitis, due to pollen allergy [141] . at last, mannans should be mentioned. they have been reported to possess adjuvant-vaccine properties in clinical studies, probably mediated by its interaction with mannose receptors. particularly, it has been shown that oxidized mannan-mucin 1 can be useful as an adjuvant in the breast cancer immunotherapy. indeed, a 12-15 years follow-up has highlighted that it decreases the cancer recurrence rate and prolongs recurrence time, without inducing toxicity or adverse reactions [124] . fatty acids (fa) are a large group of lipids, characterized by a different number of carbons, arranged in a linear carbon chain skeleton of variable length with a terminal carboxylic group [142] . based on the number of carbons in the chain, fatty acids can be classified as shortchain fatty acids (scfa; aliphatic tails up to a maximum of six carbons), medium-chain fatty acids (mcfa; aliphatic tails of 7-12 carbons), long-chain fatty acids (lcfa; aliphatic tails of 13 to 21 carbons) and very long-chain fatty acids (vlcfa; aliphatic tails of 22 and more carbons) [143] . among them, scfa, such as acetate, propionate, and butyrate, are produced by gut microbiota enzymes (i.e., propionate-coa transferase and propionaldehyde dehydratase) during the metabolism of carbohydrates and peptides containing branched-chain amino acids [144] . bacteroidetes are reported to be mainly responsible for the production of acetate and propionate, while firmicutes are the primary contributors of butyrate; however, other bacteria such as lactobacillus and bifidobacterium spp. are involved too [144] . based on the presence of different double bonds in this structure, fatty acids can be distinguished in saturated fatty acids (sfa), lacking double bonds in their carbon backbone, and unsaturated fa (ufa), which may contain one or more double bonds, thus leading to monounsaturated (mufa) and polyunsaturated fa (pufa) [143] . sfa include palmitic acid (c16:0), lauric acid (c12:0), myristic acid (c14:0), and stearic acid (c18:0), whereas n-9 oleic acid (c18:1) is an example of mufa. furthermore, pufa class includes fatty acids such as α-linolenic acid (ala; c18:3), linoleic acid (la; c18:2) and further long-chain metabolites [143] . the number of carbon atoms and unsaturated bond position are used for the systematic nomenclature of fa. moreover, the greek letters omega (ω) and delta (∆) are included, to indicate how far a double bond is from the terminal methyl carbon and the presence and position of one or more double or triple bonds in the carbon backbone, respectively [143] . a further "ω" or "n" classification designates the position of the first double bond in the skeleton from the end opposite to the carboxy group. accordingly, oleic acid is classified as a ω-9 (or n-9) fatty acid, while linoleic acid and α-linolenic acid are ω-6 (or n-6) and ω-3 (or n-3) fatty acids, as they contain the double bond nine, six and three carbons from the methyl end [143] . nomenclature of the major representative fatty acids in the different fa classes is displayed in table 3 . unsaturated fatty acids can be characterized on the basis of the cisor transorientation of the double bonds. usually, natural fatty acids carry a cisconfiguration, although some trans-fatty acids can also occur in foods as a consequence of the hydrogenation process, which can move double bonds from their naturally occurring position to a trans-configuration [143] . trans-fatty acids are considered undesirable compounds in foods, as their intake is associated with an increased risk of cardiovascular and metabolic diseases [145] . pufa can be further classified depending on the relative positions of the double bonds, as conjugated (double-bonded carbon atoms alternate with single bonds) and unconjugated (double bonds separated by one or more single bonds) [143] . unconjugated pufa, especially ω-3, ω-6, and ω-9 series, are the most occurring in nature. the most common conjugated pufa are trienes, such as octadecatrienoic acids (e.g., punic acid, calendic acid). fatty acids within the series are biosynthetically related, being synthesized through enzymatic processes of desaturation, chain elongation, and chain shortening [146] . particularly, the biosynthesis of ω-3 and ω-6 pufa starts from α-linolenic acid (ala or linolenate; 9,12,15-18:2) and linoleic acid (la or linoleate; 9,12-18:2), respectively ( figure 6 ). these precursors cannot be synthetized by mammals, which lack the ∆12 and ∆15 desaturases responsible for the convertion of 18:1 ω-9 fa to 18:2 ω-6 and 18:3 ω-3 pufa, and must be supplied by the diet, thus being considered as essential fatty acids. the initial rate-limiting step for the biosynthesis of ω3 and ω6 fatty acids is the insertion of a further double bond at the ∆6 carbon into the carbon chain of ala and la, through the help of a ∆6 desaturase enzyme: stearidonic acid (sa; 6,9,12,15-18:4) and γ-linolenic acid (gla; 6,9,12-18:3) are formed, respectively. these compounds are converted to eicosatetraenoic acid (eta; 2,4,6,8-20:4) and dihomo γ-linolenic acid (dgla; 8,11,14-20:3) by the elongase 5, being further converted to eicosapentaenoic acid (epa; 2,4,6,8,10-20:5) and arachidonic acid (aa; 5,8,11,14-20:4) , by the addition of a double bond at the ∆5 position, through a ∆5 desaturase. further elongations convert epa and aa to docosapentaenoic acid (2,4,6,8,10-22:5) and adrenic acid (7,10,13,16-22:4) ; then, a desaturation by ∆6 desaturase generates docosahexaenoic acid (dha; 4,7,10,13,16,19-22:6) [146] . both series of fatty acids can be further metabolized by cyclooxygenase and lipoxygenase enzymes, to obtain eicosanoids, including prostaglandins, thromboxanes and leukotrienes, acting as central modulators of the inflammatory process [146] . the byosynthetic pathways of ω3 and ω6 fatty acids are interconnected; indeed, it is known that long-chain derivatives from linolenic acid are accumulated in tissue only slightly when competing ω6 analogues exceed their amounts. therefore, suitable levels can be reasonably obtained through diet and when an optimum ratio of ω3 and ω6 series is maintained. both series of fatty acids can be further metabolized by cyclooxygenase and lipoxygenase enzymes, to obtain eicosanoids, including prostaglandins, thromboxanes and leukotrienes, acting as central modulators of the inflammatory process [146] . the byosynthetic pathways of ω3 and ω6 fatty acids are interconnected; indeed, it is known that long-chain derivatives from linolenic acid are accumulated in tissue only slightly when competing ω6 analogues exceed their amounts. therefore, suitable levels can be reasonably obtained through diet and when an optimum ratio of ω3 and ω6 series is maintained. figure 6 . biosynthetic pathways of ω-3 and ω-6 fatty acids. fatty acids occur widely in nature, being identified in both animal tissue and plants. particularly, short-chain saturated acids are components of milk fats: in bovine milk, butanoic acid along with other scfa and mcfa have been reported [147] . likewise, the mcfa lauric acid and myristic acid are the major components of the oils obtained from some lauraceae and myristiceae species [148] . moreover, palmitic acid is the most representative sfa in vegetable oils, such as palm oil [149] . fatty acids with immune modulating properties mainly belong to the long-chain classes; among them, punicic acid is a peculiar conjugated triene, found to be a unique component of pomegranate seed oil [150] , while oleic acid is one of the most widely distributed fatty acids: it represents 49% to 83% of total fa in olive oil, although it does occur in high amounts in other oils, such as those from grape seeds, canola and sufflower [151, 152] . moreover, ω3 and ω6 fatty acids have been highlighted in several natural sources, wherein both series co-occur (table 4) , although in different amounts [153] . table 4 . major natural sources of long-chain monounsaturated (mufa) and polyunsaturated fatty acids (pufa) associated with immune system modulating activities and relative amounts. some vegetable oils, including rapseed, hemp seed, and sunflower oils, contain higher levels of la (essential ω6 pufa), while ala (essential ω3 pufa) is in lower proportion; a similar trend has also been reported for soybean, corn, and for dried black walnuts and brazilnuts; conversely, higher amounts of ala respect to la are reported in flaxseed oil and in the seeds of chia and perilla [153] . likewise, green leafy vegetables seem to be an interesting source of ala [163] . fish oils are also sources of both epa and dha (ω3 pufa), with lower amounts of dpa (ω6 pufa) [153] . wild marine species showed to contain higher ω3 pufa levels compared to farmed ones, likely due to the feed composition [153] . some vegetables can supply both the essential pufa and some derivative fatty acids. particularly, the oils obtained from the seeds of borago spp., echium spp., ranunculus spp. and oenothera biennis l. have been reported to contain high levels of both la and γ-linolenic acid (gla) [159, 160] . fatty acids play energetic, metabolic, and structural functions, being the main component of phospholipids, triglycerides, diglycerides and monoglycerides. a separate category is represented by scfa, which act as metabolites of carbohydrates, produced by gut microbiota: their role in the modulation of immune function is described in section 2.3. long-chain fatty acids have been found involved in immune modulation, being able to affect both innate and adaptive response. although specific profiles characterize each class of fatty acids, these effects are mainly ascribed to their ability to target the cell membrane, where they can be incorporated, thus changing membrane composition and fluidity and modulating membrane-protein interaction and signal transduction. furthermore, a role in the control of inflammation has been reported. epithelial growth factor receptors (a critical crossroad of multiple receptor pathways which is potentially implicated in the regulation of proliferation and possibly involved in atherogenesis) are considered possible targets for unsaturated fatty acids [164] . mufa, especially oleic acid, have attracted great attention in the years as possible immunomodulating nutrients. preclinical studies demonstrated the ability of oleic acid to modulate the immune system, through affecting both innate and adaptive immunity response [164] . indeed, it diminished nk cell activity [165] and the expression of the leucocyte adhesion molecules, which have shown to be implicated in some pathophysiological conditions, such as rheumatoid arthritis [165] . furthermore, it enhanced neutrophil aggregation and neutrophil-endothelial cell attachment, phagocytic and candidacidal capacities [166, 167] . in regard to adaptive response, it inhibited the proliferation of immune cells, such as jurkat t cells and lymphocytes, likely through the regulation of the cell cycle, although the true mechanisms remain to be clarified [164] . similar suppressive effects were also highlighted for its synthetic analogue minerval and confirmed in animal models [164, 168] . furthermore, the treatment with oleic acid and minerval induced proapoptotic effects in jurkat (t lymphocyte) and raji (b lymphocyte) cells, likely due to mitochondrial depolarization and ros production [168] [169] [170] . recently, oleate has been reported to be able to protect macrophages from palmitate-induced lipotoxicity; moreover, it has been associated with an increase in the regulatory phenotype of the myeloid msc-2 suppressor cells and suppression of activated t cells [171, 172] . in the skin, oleic acid, along with other unsaturated fa, seems to be incorporated into the lipid moiety of staphylococcus aureus lpp, inducing an immune response against the pathogen [173] . regarding conjugated pufa, punicic acid has been shown to improve the immune system development, stimulate the cd4+ and cd8+ lymphocyte-mediated immunity and increase the immune response against viruses [174] . these immune boosting effects are due to nuclear peroxisome proliferator-activated receptor (ppar)γ-and δ-dependent mechanisms, as punicic acid is able to act as an agonist of these receptors; in support, the loss of pparγ in immune cells impaired its effects [174, 175] . moreover, punicic acid inhibited the tnf-α-induced priming of ros production by inhibiting the ser345-p47phox phosphorylation and upstreaming kinase p38mapk; likewise, it blocked the tnf-α-induced release of myeloperoxidase from neutrophils, and decreased neutrophil-activation and ros/mpo-mediated tissue damage in vivo [176] . antinflammatory properties were found to be related to the activation of pparγ and the suppressed expression of inflammatory genes (encoding cytokines, chemokines, cyclooxygenase, no synthase, and metalloproteinases) [150] . immunomodulatory properties of ω-6 and ω-3 pufa have been highlighted in different preclinical models and have been associated with their ability to modulate the inflammatory process [177] . these fatty acids share common biosynthetic enzymes which mediate the production of different series of eicosanoids, starting from typical precursors, including dihomo-γ-linoleic acid (dgla), arachidonic acid (aa) and eicosapentaenoic acid (epa). among prostanoids, three types of prostaglandins (pg), including pg1, pg2 and pg3, can be obtained. pg1 is associated with beneficial effects and lower inflammation, thus being considered as an antinflammatory prostanoid; conversely, pg2 has opposite behaviour, increasing inflammation, vasoconstriction and blood clotting. pg3 acts through a mixture of functions and is able to reduce the pg2-mediated inflammation [177] . starting from dgla, both anti-inflammatory pg1 and pro-inflammatory pg2, through the conversion into arachidonic acid, can be produced (figure 7) . effects and lower inflammation, thus being considered as an antinflammatory prostanoid; conversely, pg2 has opposite behaviour, increasing inflammation, vasoconstriction and blood clotting. pg3 acts through a mixture of functions and is able to reduce the pg2-mediated inflammation [177] . starting from dgla, both anti-inflammatory pg1 and pro-inflammatory pg2, through the conversion into arachidonic acid, can be produced (figure 7) . this synthesis is controlled by the activity of δ5-desaturase and δ6-desaturase enzymes, which are often compromised during inflammatory conditions and diseases. it has been found that diets enriched in ω-3 fatty acids are able to activate the conversion of dgla into pg1, whereas low ω-3 intake induces the conversion in aa with the synthesis of proinflammatory prostanoids [178] . aa can also be released by the cell membranes through the action of phospholipase a2 during cell injuries or changes in biomembrane composition, thus representing a physiological activator of inflammation as a defence response. aa and eicosapentaenoic acid (epa) compete for the synthesis of different series of pg, mediated by cyclooxigenase, while 5-lipooxygenase (lox) is involved in their conversion into thromboxanes and leukotrienes. particularly, tromboxane a2 and leukotriene b4 are produced from aa, while tromboxane a3 and leukotriene b5 from epa. epa and dha are also precursors of lipoxins, resolvins and protectins, which produced anti-inflammatory effects and regulate vascular tone and blood pressure [178] . like punicic acid, the anti-inflammatory effects of epa and dha are mediated by the activation of the pparα/γ [179] . despite the antinflammatory role of ω-3 and ω-6-based diets, aa increases the plasmatic levels of proinflammatory eicosanoids, associated with an increased incidence of allergic and inflammatory disorders and with excessive cell proliferation. anyhow, it is not clear the usefulness to select ω-3 with respect to ω-6 in the diet: a balance between ω-3 and ω-6 pufa seems to be essential for mantaining ahealth status. the ability of fatty acids to be incorporated in the cell membrane seems to represent a key mechanism accounting for the immunomodulating properties of ω-3 and ω-6 pufa. indeed, immune cells (i.e., t cells and neutrophils) can incorporate exogenous fatty acids into membrane with a lateration in the function of cell surface pattern recognition receptors [180] . dietary ω-3 pufa has been shown able to modulate the macrophage function, through the activation of g protein coupled receptors (gpr) and to induce a shift to an anti-inflammatory phenotype [49] . modulating signalings through the gpr receptor activation can also affect leukocyte function. likewise, an inhibition of the pro-inflammatory phenotype of dendritic cells and of the t cell responses has been reported [49] . they are also able to inhibit neutrophil and monocyte adhesion, depending on the activation of ppar-α [49] . conversely, ω-6 pufas seem to promote inflammation, associated with incresead ros levels, in neutrophils [49] . particularly, linoleic acid increased the marginated pool of neutrophils in tissues by the induced expression of adhesion molecules;it also complexed with the anti-inflammatory this synthesis is controlled by the activity of ∆5-desaturase and ∆6-desaturase enzymes, which are often compromised during inflammatory conditions and diseases. it has been found that diets enriched in ω-3 fatty acids are able to activate the conversion of dgla into pg1, whereas low ω-3 intake induces the conversion in aa with the synthesis of proinflammatory prostanoids [178] . aa can also be released by the cell membranes through the action of phospholipase a2 during cell injuries or changes in biomembrane composition, thus representing a physiological activator of inflammation as a defence response. aa and eicosapentaenoic acid (epa) compete for the synthesis of different series of pg, mediated by cyclooxigenase, while 5-lipooxygenase (lox) is involved in their conversion into thromboxanes and leukotrienes. particularly, tromboxane a2 and leukotriene b4 are produced from aa, while tromboxane a3 and leukotriene b5 from epa. epa and dha are also precursors of lipoxins, resolvins and protectins, which produced anti-inflammatory effects and regulate vascular tone and blood pressure [178] . like punicic acid, the anti-inflammatory effects of epa and dha are mediated by the activation of the pparα/γ [179] . despite the antinflammatory role of ω-3 and ω-6-based diets, aa increases the plasmatic levels of proinflammatory eicosanoids, associated with an increased incidence of allergic and inflammatory disorders and with excessive cell proliferation. anyhow, it is not clear the usefulness to select ω-3 with respect to ω-6 in the diet: a balance between ω-3 and ω-6 pufa seems to be essential for mantaining ahealth status. the ability of fatty acids to be incorporated in the cell membrane seems to represent a key mechanism accounting for the immunomodulating properties of ω-3 and ω-6 pufa. indeed, immune cells (i.e., t cells and neutrophils) can incorporate exogenous fatty acids into membrane with a lateration in the function of cell surface pattern recognition receptors [180] . dietary ω-3 pufa has been shown able to modulate the macrophage function, through the activation of g protein coupled receptors (gpr) and to induce a shift to an anti-inflammatory phenotype [49] . modulating signalings through the gpr receptor activation can also affect leukocyte function. likewise, an inhibition of the pro-inflammatory phenotype of dendritic cells and of the t cell responses has been reported [49] . they are also able to inhibit neutrophil and monocyte adhesion, depending on the activation of ppar-α [49] . conversely, ω-6 pufas seem to promote inflammation, associated with incresead ros levels, in neutrophils [49] . particularly, linoleic acid increased the marginated pool of neutrophils in tissues by the induced expression of adhesion molecules; it also complexed with the anti-inflammatory molecule 1-antitrypsin, thus reducing lps-induced il-1 secretion in neutrophils [49] . on the whole, preclinical evidence highlighted that these fatty acids could increase neutrophil function, thus promoting innate immunity. regarding adaptive immunity, ω-3 pufa have been reported able to improve the mitogen-mediated activation of immune cells and to promote the development of a th2-type immune response [180] . moreover, an increased production of associated anti-inflammatory cytokines like il-4, in spite of a reduction of pro-inflammatory tnf-α, was found [180] . similar effects were highlighted with both fish oil-enriched diets and the purified epa and dha [49] . the beneficial influence of ω-3 pufa has been highlighted also on epithelial cells during inflammation, being able to restore impaired barrier function and reduce the production of pro-inflammatory mediators [49] . moreover, a strictly interplay between omega-3 fatty acids, immunity and gut microbiota has been reported and seems to be an essential factor to maintain the intestinal wall integrity. these effects have been ascribed to the ability of ω-3 pufa to positively affect the microbiota composition and increase the production of anti-inflammatory compounds, like short-chain fatty acids [181] . although a major interest over the years has been focused on marine sources of ω-3-enriched oils or on pure compounds, some plant species have been studied for their immunomodulating and anti-inflammatory properties, likely ascribable to ω-3 and/or ω-6 pufa, although the major evidence has been highlighted for linum usitatissimun l., oenothera biennis l. and borago officinalis l. [160, 182, 183] . the seed oil from l. usitatissimum, also known as flaxseed oil, has been reported to induce immunomodulating effects, likely through suppressing cell mediated immunity, without the involvement of humoral immunity. being a rich source of ala, its effects are mainly ascribed to this compound, although further studies suggested a possible contribution of bioactive phenolics [184] . flaxseed oil was found to be effective in reducing skin inflammatory responses, although with a lower immunosuppressive power with respect to fish oil [185] . moreover, it improved systemic and gut immunity, in a piglet model with intrauterine growth retardation: increased plasma concentration of immunoglobulin g, decreased cd3+cd8+ t lymphocytes, and the downregulation of genes expression for proinflammatory factors have been reported [186] . regarding o. biennis, the administration of the seed oil (namely, evening primrose oil) in animal models enhanced pge1 synthesis in peritoneal macrophages, decreased pge2 amounts in granulocytes, and suppressed the natural killer (nk) cell activity and lymphocyte proliferation; moreover, it decreased the serum levels of interferon γ (ifn-γ) and mcp-1, while stimulating tnf-α [187] [188] [189] [190] [191] . furthermore, anti-inflammatory effects have been found to be involved in the immunomodulation by evening primrose oil [160] . these effects were ascribed to the content of gla, whose t-regulatory cell activity in autoimmune disease models was highlighted [192] . however, a contribution of la to the antinflammatory effects seems to be likely; indeed, la can itself modulate inflammation as it is metabolized by lox to hydroxyoctadecadienoic acids (hodes) and oxo-hodes, characterized by antinflammatory properties [193] . similarly, the seed oil from b. officinalis seeds produced immonomodulating and antinflammatory effects, likely through its gla content [183] . a chemotactic migration of monocytes to necrotic site that differentiate into macrophages is associated with the administration of this product. moreover, it is known to reduce the levels of proinflammatory cytokines, such as tnf-α, and to promote pge1 generation; a reduced expression of inflammatory genes, especially those of macrophages involved in atherosclerosis, has been reported too [183] [184] [185] [186] [187] [188] [189] [190] [191] [192] [193] [194] . clinical studies mainly focused on the effects of fatty acid-enriched diet on inflammation, although specific immune-based pathological conditions associated with inflammation were assessed too. regarding mufa, few studies are available, and results differ from those in animal models. indeed, a mufa-rich diet (with highly refined olive oil for 8 weeks) did not alter the immune function in healthy subjects; such effects could be due to the high amounts administered in animal models [164] . conversely, clinical evidence about the immunomodulatory power of punicic acid in healthy or sick subjects is lacking [150] . the ω-3 pufa series and the relative enriched fish oils have been mainly evaluated for their immunomodulating and antinflammatory effects in humans. although preclinical evidence highlighted their ability to influence both innate and adaptive immunity, the clinical relevance of these results remains to be clarified, due to lacking or inconclusive data [49] . inadequacy of clinical results should be due to the different doses used in preclinical studies, wherein often high fatty acids levels were administered; moreover, other factors such as genetic and epigenetic heterogeneity of the recruited subjects, diet diversity, nutritional habits and microbiome can be considered as additional confounding factors [49] . although limitations of clinical studies require further confirmation, ω-3 pufa intake produced significant clinical benefits and reduction of the symptoms in patients with autoimmune disorders, especially rheumatic diseases and systemic lupus erythematosus [195] [196] [197] . in support, low levels of pufas have been found in the serum of patients with rheumatic diseases [198] . conversely, inconsistent results are reported for multiple sclerosis, thus the possible usefulness of these fatty acids as supportive therapy requires more clinical trials [199] . regarding ω-6 pufa, although they are associated with possible increased inflammatory conditions, being arachidonic acid a presursor of proinflammatory prostanoids, such a risk is not confirmed by clinical evidence [200] . indeed, studies in healthy human adults highlighted that an increased intake of these fatty acids did not induce inflammation; conversely, epidemiological evidence reported reduced inflammatory conditions [200] . the antinflammatory effects of la have been reported too [193] . similarly, increased la intake was found to be not related to increased amounts of ara and proinflammatory factors; however, an inverse correlation with epa and dha was reported [201] . this suggests that the interaction between ω-e and ω-6 series is regulated by complex mechanisms that requires further clarifications. major clinical studies have been performed using evening primrose oil (from the seeds of o. biennis), as a source of la and gla, in inflammatory diseases associated with immune system disorders, including atopic dermatitis, psoriasis, multiple sclerosis and rheumatoid arthritis. standardized oils for the content in la and ala (for instance, efamol is titred to contain 72% la and 9% gla) were usually used [202] . the treatment with evening primrose oil (4 and 7 weeks) produced clinical improvements in patients with atopic dermatitis, as revealed by measuring the scoring atopic dermatitis [203] . some beneficial effects were also reported in multiple schlerosis patients, although the few available studies limited the evidence in this disorder. conversely, evening primrose oil in combination with fish oil and vitamin e (efamol marine) failed to improve the symptoms of psoriasiac patients but produced antinflammatory effects [204] . similarly, in association with ω-3 fatty acids, it did not induce improvements in patients with rheumatoid arthritis [205] . a cochrane revision highlighted moderate evidence for oils containing gla (i.e., evening primrose, borage, or blackcurrant seed oil) to produce benefit in rheumatoid arthritis [205, 206] . evening primrose oil along with borage oil were not effective to treat eczema too [207] . highly variable results were also obtained for borage oil in the treatment of atopic dermatitis, although, in all the studies, a moderate efficacy degree was displayed [208] . regarding flaxseed oils, some clinical trials higlighted a significant improvement of inflammatory parameters in subjects with cardiovascular diseases non-associated with the immune system [209] . reported studies, although performed in pathological conditions associated with immune system disfunction, did not give a direct measure of the immunomodulatory effects of the treatments. furthermore, specific and high-quality studies are required for better characterizing the possible usefuleness of these pufa-enriched oils as anti-inflammatory and immunomodulating treatments. labdane compounds have a molecular formula c 20 h 38 with an average mass of 278.516 da ( figure 8 ). labdane-related molecules have a hydrocarbon skeleton, originated from dual biosynthetic cyclization and/or rearrangement reactions, produced through the biosynthetic pathway of gibberellin phytohormones by the diterpene cyclases. the labane diterpenoids belong to a superfamily of natural products, in which the hydrocarbon skeleton might serve as privileged scaffolds for their biological activity [210] . labdane compounds have a molecular formula c20h38 with an average mass of 278.516 da ( figure 8 ). labdane-related molecules have a hydrocarbon skeleton, originated from dual biosynthetic cyclization and/or rearrangement reactions, produced through the biosynthetic pathway of gibberellin phytohormones by the diterpene cyclases. the labane diterpenoids belong to a superfamily of natural products, in which the hydrocarbon skeleton might serve as privileged scaffolds for their biological activity [210] . labdane diterpenes have been found in the various matrix of vegetal origin (leaves, rizomes, fruits, etc.) of different plants. in table 1 , some of them (where diterpenes have been found), their botanical family (in parentheses) and the part of plant of biological interest are reported. some labdane diterpenoids, isolated from plant matrix, include the following: andrographolide ( figure 9 ) (from andrographis paniculata (burm.f.) nees) [211] , labda-8(17), 12-diene-15, 16-dial (from curcuma amada roxb) [212] , podoimbricatin c (a 12,17-cyclo-labdane diterpenoid from dacrycarpus imbricatus (blume) de laub) [213] chapecoderins a-c (from echinodorus macrophyllus (kunth) micheli), [214] , (4r,5s,9s,10r)-13-des-ethyl-13-oxolabda-8(17),11e-dien-19-oic acid (from juniperus oblonga m. bieb) [215] , leoheteronin d and leojaponin a (from leonurus japonicus houtt) [216] , marrubasch a-f and marrubenol (from marrubium aschersonii p.magnus), marrulibanoside (from marrubium globosum boiss. and balansa) [217] , vitexlimolides a-c (from vitex limonifolia wall. ex c.b. clarke) [218] . labdane diterpenes have been found in the various matrix of vegetal origin (leaves, rizomes, fruits, etc.) of different plants. in table 1 , some of them (where diterpenes have been found), their botanical family (in parentheses) and the part of plant of biological interest are reported. some labdane diterpenoids, isolated from plant matrix, include the following: andrographolide ( figure 9 ) (from andrographis paniculata (burm.f.) nees) [211] , labda-8(17), 12-diene-15, 16-dial (from curcuma amada roxb) [212] , podoimbricatin c (a 12,17-cyclo-labdane diterpenoid from dacrycarpus imbricatus (blume) de laub) [213] chapecoderins a-c (from echinodorus macrophyllus (kunth) micheli), [214] , (4r,5s,9s,10r)-13-des-ethyl-13-oxolabda-8(17),11e-dien-19-oic acid (from juniperus oblonga m. bieb) [215] , leoheteronin d and leojaponin a (from leonurus japonicus houtt) [216] , marrubasch a-f and marrubenol (from marrubium aschersonii p.magnus), marrulibanoside (from marrubium globosum boiss. and balansa) [217] , vitexlimolides a-c (from vitex limonifolia wall. ex c.b. clarke) [218] . imbricatus (blume) de laub) [213] chapecoderins a-c (from echinodorus macrophyllus (kunth) micheli), [214] , (4r,5s,9s,10r)-13-des-ethyl-13-oxolabda-8(17),11e-dien-19-oic acid (from juniperus oblonga m. bieb) [215] , leoheteronin d and leojaponin a (from leonurus japonicus houtt) [216] , marrubasch a-f and marrubenol (from marrubium aschersonii p.magnus), marrulibanoside (from marrubium globosum boiss. and balansa) [217] , vitexlimolides a-c (from vitex limonifolia wall. ex c.b. clarke) [218] . figure 9 . chemical structure of andrographolide. this has been obtained using chemspider ® chemical structure database. the body's defense responses can be improved through various properties induced by plants. some of them, referring to the plants in table 5 , are shown below. for each plants and plant-derived nutraceutical, only properties potentially attributable to the labdane skeleton and useful to improve the immune system are reported. as both inflammation (biological response of body tissues to harmful stimuli) and oxidative stress (imbalance between reactive oxygen species and a biological system's ability to detoxify/repair the resulting damage of the reactive intermediates) are the main self-defend methods to eliminate pathogens and protect living bodies, plants with antinflammatory and/or radical scavenger properties are considered too [211] . indeed, labdane diterpenoids have recently gained greater attention from the scientific point of view, due to a wide range of biological activities, including the anti-inflammatory modulation of immune cell functions [217] . a. paniculata exhibited, in vitro and in vivo, various pharmacological activities, including antihyperglycemic, antiplatelet aggregation, anti-microbial, anti-inflammatory, anti-hiv, anti-cancer, anti-nociceptive activity, etc. it has also been used for autoimmune encephalomyelitis and, in indian and chinese medicine, for respiratory tract infections [217, 219] . more recently, a. paniculata has been used to stimulate the immune system and treat myocardial ischemia [211] . a. paniculata inhibited interleukin (il)-6, tnf-α mrna, lps-induced expression, and suppressed levels of tnf-α, il-1β, jnk, c-reactive protein, and nf-κb [211] . many labdane diterpenoids compounds have been found to act on the latter. the activation of the nf-κb pathway leads to several physiological responses, including inflammatory or innate immune response [217] . in vitro, andrographolide (the main phytoconstituent of a. paniculata) can inhibit inflammation, by regulating protein expression (cytokines, chemokines) and by reducing immune cell infiltration. andrographolide was shown to inhibit also oxidative stress by binding to adenosine a2a receptor, by inducing nuclear factor (erthroid-derived 2)-like 2 (nrf2) translocation, and by increasing the expression of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase-2 [211] . these effects can contribute to the immunoregulatory activity of this plant-derived nutraceutical, as it can modulate the innate and adaptive immune responses by regulating macrophage phenotypic polarization and antibody productions [25] . moreover, it was found to exert cytotoxic/anticancer effects on almost all types of tumour cell lines (human leukemia, renal tubular epithelial cells, breast cancer cells, etc.), mainly by cell cycle arrest, autophagy, cell death, anti-inflammatory and immune system mediated effects [220] . other preclinical studies have highlighted pharmacological properties of labdane diterpenoidscontaining plants. data are limited, and consequently also their preclinical evidence. some examples are reported below. c. amada, also known as mango ginger, and its labdane-diterpenoids have shown antiflammatory, antibacterial, insecticidal, antifungal, antipyretic, antioxidant, anticancer, and antitubercolar properties in preclinical trials [212] . d. imbricatus displayed cytotoxic and anti-neuroinflammatory activities, but it had no cytotoxic activity against human tumour cell lines [213] . e. macrophyllus, brazilian plant, also known as "leather hat", is used as a methanolic (which contains mainly labane diterpenoids, steroids, alcaloids, etc.) or aqueous extract (rich in flavonoids) of the aerial parts, leaves in particular. in folk medicine, e. macrophyllus is used for various illnesses (respiratoy and urinary diseases, rheumatoid arthritis, atherosclerosis, etc.), as it has been shown to possess tissues protective activity and immunosuppressive effects (impaired secretion and function of b and/or t cells), on humoral or cellular immune responses and on autoimmune rheumatic diseases [221] . in in vitro/vivo studies, the aqueous extract of e. macrophyllus exhibited strong antinflammatory activities by decreasing rats paw edema, inflammatory exudates, infiltrate tissues, no production, ltb4 release, and neutrophil migration [222] . in preclinical studies, the methanolic extract of e. macrophyllus was not cytotoxic, genotoxic, mutagenic, and no acute toxicity (up to the maximum dose of 2000 mg/kg b.w.) has been observed in tested animals [221] . however, the extrapolation of animal experiments to clinical practice must be done with caution [223] . compounds from j. oblonga have shown anti-tumor effects, through moderate cytotoxicity against human tumor cell lines obtained from various human tissues, including: hepatocellular carcinoma (hepg2), breast cancer (mcf-7), and cervical carcinoma cancer (hela) [215] . the berries from j. oblonga also have antimicrobial activity and anti-inflammatory effects. labdane diterpenoid (e.g., leonurine), extracted from l. japonicus, exhibited cytotoxicity and cell cicle arrest against cancer cell lines and presented immunomodulatory and antinflammatory activities (suppresses tnf-α, nf-κb, and down-regulated expression of inos, cox2, and conseguently peg2 and no levels) [216] . marrubium spp. (aschersonii, globosum, etc.) have multiple actions, including antimicrobial and anti-inflammatory activities. marrubasch a-f and marrubenol, isolated from the ethanolic extract of m. aschersonii, exhibited weak reduction in inos activity and, consequentely, no production [217] . marrulibanoside, obtained from the aerial parts of m. globosum, inhibited catalytic activity of inos and cox-2enzymes, and consequentely, the peg2 and no production. v. limonifolia, in preclinical trial, have shown a strong antiviral activity against coxsackievirus b3, human rhinovirus 1b, and enterovirus 71 (ev71). all of them could be responsible for various illnesses, ranging from common cold, hand, foot, and mouth diseases, to acute flaccid paralysis [218] . the clinical efficacy of the medicinal plants, and plant-derived nutraceuticals discussed above are almost totally lacking. only for a. paniculata there are some evidence in humans. andrographis extract (various and not standardized), andrographolide, and its derivatives have been studied in the treatment of various disease (multiple sclerosis, infection disease, gastro-intestinal upsets, respiratory ailments, pain), and in the maintenance of immune function. in this last context, it seemed to improve the response to cough and sore throat, shortening the sick leave/time to resolution [219] . the most interesting activity is the increase of cd4+ lymphocyte levels, in hiv-positive patients [211] . the increase in these lymphocytes testifies an improvement in the state of the immune system. moreover, a chinese product containing andrographolide improved the efficacy of glucocorticoids and immunoglobulin in patients with severe hand, food, and mouth disease. however, andrographolide is considered a hazard, as it is irritating, and its injectable use is limited because it could induce allergic reactions (erythema, pruritus, etc.), which are sometimes life-threatening [211] . preclinical data suggested that andrographolide could be responsible of pharmacokinetics interactions, as it induced cyp1a2 [219] . the european medicines agency (ema) reports a possibility of causing reproductive toxicity of andrographis extracts (decreases in sperm motility and counts) [219] . on the other hand, no major adverse effects have been reported for a. paniculata; only minor side effects, mainly gastrointestinal, are known [219] . notably, even if a. paniculata presents numerous pharmacological properties, andrographolide possess poor solubility (principally in dmso), which severely limits the possibility of achieving a therapeutic effect (if not properly formulated). its better absorption could be achieved by nano-formulations (e.g., nano-emulsion, nano-capsules). immunomodulation by plant-based nutraceuticals represents an interesting tool to be exploited for the treatment and preventing purposes of immune system disorders, due to their multiple bioactivities, well tolerability and good patient compliance. however, as often reported for several herbal medicinal products, some points require being underlined to improve the research in the field and provide solid evidence to support their rational use. according to previous stated critical issues [224, 225] , herbal products under study must be characterized for the phytochemical composition, using validated analytical methodologies, and for the extraction procedures; moreover, the starting material should be fully defined in terms of origin (country and region), cultivation conditions, botanical identity and plant part. the content of specific compounds, used as analytical or active markers, should be determined too. these requirements are needed to ensure reproducible pharmacological/clinical activity and to compare different studies. indeed, using nonstandardized phytocomplexes increases variability of the biological response, thus limiting the reliability and validity of the studies. furthermore, to assess the pharmacological activity of specific compounds, purity (at least 95%) and identity should be characterized. indeed, when assessed as mixtures, the subtle interactions which can be established among phytochemicals make it difficult to understand whether the observed benefits are attributable to a specific class or to the whole phytocomplex. for instance, both fatty acids and polyphenols can be involved in the immunomodulating effects of pufa-enriched plant oils. moreover, as found for both polysaccharides and fatty acids, among the same class, different subclasses can co-occur, thus contributing to the whole effects. regarding preclinical studies, detailed methodologies, including information about specific extraction process, the choice of the tested concentrations and experimental procedures, vehicle effects, and comparison with standard effective compounds (positive controls) should be reported. in order to validate the "goodness" of the treatment, promising results in preclinical studies should be confirmed by clinical evidence of efficacy and lack of toxicological concerns for both the isolated compounds and the whole phytocomplex. at last, possible interactions with diet constituents or possible pharmacological treatments, as reported for andrographolide, which is a cyp1a2 inducer, should be considered. as highlighted for a number of natural products, clinical evidence is a major challenge for plant-based immunomodulating nutraceuticals too, due to limited specific studies. moreover, methodological quality of the available trials was overall poor, the studies often being not blinded, protocol unavailable and lacking the standardization of tested products, thus making the claimed effect difficult to be reproduced. at last, standardized methodologies for systematic reviews and meta-analyses, such as the prisma guidelines [226] , would allow a rational interpretation of the results and suggestions for future research. medicinal plants are rich sources of bioactive phytochemicals, characterized by multiple and often pleiotropic activities, which can be exploited both therapeutically and as nutraceutical strategies for preventive purposes. among plant-based nutraceuticals, immunomodulators have been highlighted to be of interest as boosters of the immune system, to counteract infectious or exogenous injuries, immunosuppressor, to control the abnormal immune response occurring during autoimmune diseases, or as adjuvants, which contribute by modulating nonimmune targets. in this review, we highlighted the scientific evidence about the immunomodulating properties of three emerging 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reproducibility of natural product research preferred reporting items for systematic reviews and meta-analyses: the prisma statement this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license a.d.s. and s.d.g. fellowships were funded by grants from sapienza university (ateneo 2019) and regione lazio. the authors thank "enrico and enrica sovena" foundation (italy) for supporting the study. the authors declare no conflict of interest. key: cord-295335-oa4twg2z authors: pastorino, giulia; cornara, laura; soares, sónia; rodrigues, francisca; oliveira, m. beatriz p.p. title: liquorice (glycyrrhiza glabra): a phytochemical and pharmacological review date: 2018-08-17 journal: phytother res doi: 10.1002/ptr.6178 sha: doc_id: 295335 cord_uid: oa4twg2z in the last years, consumers are paying much more attention to natural medicines and principles, mainly due to the general sense that natural compounds are safe. on the other hand, there is a growing demand by industry for plants used in traditional medicine that could be incorporated in foods, nutraceuticals, cosmetics, or even pharmaceuticals. glycyrrhiza glabra linn. belongs to the fabaceae family and has been recognized since ancient times for its ethnopharmacological values. this plant contains different phytocompounds, such as glycyrrhizin, 18β‐glycyrrhetinic acid, glabrin a and b, and isoflavones, that have demonstrated various pharmacological activities. pharmacological experiments have demonstrated that different extracts and pure compounds from this species exhibit a broad range of biological properties, including antibacterial, anti‐inflammatory, antiviral, antioxidant, and antidiabetic activities. a few toxicological studies have reported some concerns. this review addresses all those issues and focuses on the pharmacological activities reported for g. glabra. therefore, an updated, critical, and extensive overview on the current knowledge of g. glabra composition and biological activities is provided here in order to explore its therapeutic potential and future challenges to be utilized for the formulation of new products that will contribute to human well‐being. prepare a tea that is an excellent thirst quencher. the dried root has been described as a tooth cleanser (armanini et al., 2002) . actually, the most important industrial use of g. glabra is the production of food additives, such as flavours and sweetening agents (mukhopadhyay & panja, 2008) . in particular, the root is used as a flavouring agent for american-type tobacco, chewing gum, candies, baked goods, ice cream, and soft drinks (rizzato, scalabrin, radaelli, capodaglio, & piccolo, 2017) . in beers and fire extinguishers, the root extracts are used as foaming agents, whereas the root fibbers are used in insulation, wallboard, and boxboard materials, after removal of the medicinal and flavouring constituents. in the cosmetic field, g. glabra is described as a skin depigmentation agent and is being incorporated in topical products for that purpose. with regard to government approval, liquorice extract and glycyrrhizin have been allowed for use in foods by the united states food and drug administration, the council of europe, and the joint fao/who expert committee on food additives (fao, 2005) . indeed, the u.s. flavor and extract manufacturers association has recognized it as generally safe. to the best of our knowledge, a limited number of reviews have been published on this plant, particularly in what concerns to pharmacological aspects (asl & hosseinzadeh, 2008; fiore, eisenhut, ragazzi, zanchin, & armanini, 2005) . the objective of this review was to examine the bioactive compounds of g. glabra and the biological activities associated with these compounds. g. glabra is a typical herbaceous perennial, growing to 1 m in height, presenting pinnate leaves with a length of 7 to 15 cm. the flowers are purple to pale whitish blue, being arranged in a hermaphrodite inflorescence, whereas the fruit is an oblong legume with 2 to 3 cm of length and containing several seeds. the genus glycyrrhiza (fabaceae) consists of about 30 species, such as g. glabra, g. uralensis, g. inflata, g. aspera, g. korshinskyi, or g. eurycarpa. like the other plants of fabaceae, g. glabra is able to fix nitrogen, due to symbiosis with bacteria of the genus rhizobium, at the root level, being suitable for sandy and clay soils, though preferring humid soils. since the egyptian age, the therapeutic properties of g. glabra are well documented (fiore et al., 2005) . the roots are the most used parts whereas leaves are considered an agrochemical waste. however, in the last years, different authors studied the phytochemical composition of g. glabra leaves, demonstrating that certain compounds present in the roots are also identified in leaves, although in smaller quantities (hayashi & sudo, 2009; siracusa et al., 2011) . in the last years, the chemical constituents of liquorice have been extensively investigated by different authors siracusa et al., 2011) . nevertheless, few studies were carried out on the nutritional composition of g. glabra. nutritionally, liquorice is a source of proteins, amino acids, polysaccharides and simple sugars, mineral salts (such as calcium, phosphorus, sodium, potassium, iron, magnesium, silicon, selenium, manganese, zinc, and copper), pectins, resins, starches, sterols, and gums (q. . oestrogens, tannins, phytosterols (sitosterol and stigmasterol), coumarins, vitamins (b1, b2, b3, b5, e, and c), and glycosides have been reported (q. wang, qian, et al., 2015) . a large number of biological compounds have also been isolated, mostly triterpenes, saponins (responsible for the sweet taste), and flavonoids (rizzato et al., 2017; q. wang, qian, et al., 2015) . the liquorice saponins are present as glucuronides, whereas the aglycones are present as oleananes. the triterpene saponins are the major characteristic constituents of liquorice, being responsible for the sweet taste. the contents of these compounds may vary significantly due to geographic sources, harvesting, and processing, affecting the therapeutic effects of liquorice. the main constituent of roots is glycyrrhizin, a triterpenoid saponin that is almost 50 times sweeter than sucrose, being the primary active ingredient (j. y. yu et al., 2015) . glycyrrhizin represents about 10% of the liquorice root dry weight, being a mixture of potassium, calcium, and magnesium salts of glycyrrhizic acid that varies between 2% and 25% (rizzato et al., 2017) . after oral administration, glycyrrhizin is metabolized to 18-glycyrrhetic acid 3omonoglucuronide and glycyrrhetic acid by intestinal bacteria (albermann, musshoff, hagemeier, & madea, 2010) . the yellow colour of liquorice is due to the flavonoid content. the flavonoids identified belong to different classes, including flavanones, flavones, flavanonols, chalcones, isoflavans, isoflavenes, isoflavones, and isoflavanones. the major flavonoids are glycosides of liquiritigenin (4′,7-dihydroxyflavanone) and isoliquiritigenin (2′,4,4′trihydroxychalcone), such as liquiritin, isoliquiritin, liquiritin apioside, and licuraside (rizzato et al., 2017) . five new flavonoids have been isolated from dried roots: glucoliquiritin apioside, shinflavanone, shinpterocarpin, prenyllicoflavone a, and 1-methoxyphaseolin. pinocembrin and licoflavanone were also isolated from the leaves (fukui, goto, & tabata, 1988) . glabridin is the principal isoflavone identified, ranging between 0.08% and 0.35% of roots' dry weight (simmler, pauli, & chen, 2013 liquorice is one of the oldest and most popular herbal medicines in the world. many of the liquorice historical uses are still practised the antioxidant activity of g. glabra is one of the major reasons for its uses. the phenolic content is probably responsible for the powerful antioxidant activity observed (rackova et al., 2007) . varsha and sonam (2013) attributed this activity to flavonoids, whereas singh et al. (2015) reported that mostly isoflavones, such as glabridin, hispaglabridin a, and 30-hydroxy-4-o-methylglabridin, are the responsible compounds. biondi, rocco, and ruberto (2003) reported a huge antioxidant activity of the dihydrostilbene derivates present in g. glabra leaves. also, licochalcones b and d are present in g. glabra, showing a strong scavenging activity on dpph radical and the ability to inhibit the microsomal lipid peroxidation (biondi et al., 2003; v. sharma, katiyar, & agrawal, 2016) . these phenolic compounds are effective in the protection of biological systems against oxidative stress, being able to inhibit the onset of skin damages (haraguchi et al., 1998) . according to castangia et al. (2015) , the topical application of liquorice extract formulations may be of value in innovative dermal and cosmetic products as it counteracts oxidative stress damage, maintaining the skin homeostasis due to its high antioxidant content. table 1 summarizes the most important studies of antioxidant activity. the anti-inflammatory activity of g. glabra and its use in the treatment of inflammatory diseases have been documented since ancient times (r. yang, yuan, ma, zhou, & liu, 2017) . shalaby, ibrahim, mahmoud, and mahmoud (2004) evaluated the anti-inflammatory activity of g. glabra in male rats after 4 weeks of food intake. the authors observed a significant decrease in the total cholesterol and triglyceride levels as well as in the levels of serum liver enzymes. harwansh, patra, pareta, singh, and biswas (2011) reviewed the positive effects of g. glabra on the treatment of the upper respiratory tract and gastric system diseases. these pharmacological effects were due to an increase in the secretion of serotonin and prostaglandins in the stomach that led to a decrease of gastric inflammation (bahmani et al., 2014) . different authors described that the anti-inflammatory action is primary mediated by glycyrrhizin, which in vitro could inhibit factors responsible for inflammation as well as promote the healing of stomach and mouth ulcers (rackova et al., 2007; yin et al., 2017) . in fact, the anti-inflammatory effects of glycyrrhizin were described as similar to those of glucocorticoids and mineralocorticoids (kageyama, suzuki, & saruta, 1994) . furthermore, g. glabra is used in renal and liver complications on the basis of its strong antiinflammatory effects (y. xiao et al., 2010) . y. xiao et al. (2010) reported the inhibition of liver granuloma formation and the inflammatory cytokine production by glycyrrhizin, whereas x. r. wang, hao, and chu (2017) described the anti-inflammatory effects on endometriosis. moreover, liu et al. (2017) proved the anti-inflammatory activity of glabridin on raw cells. the antitussic and expectorant effects of liquorice have been reported by different authors, particularly its useful effects on the treatment of sore throat, cough, and bronchial catarrh (damle, 2014; fiore et al., (hasanein, 2011) glycyrrhiza glabra extract 75-300 mg/kg, 7 days in vivo-oral administration to swiss young male albino mice production of antidepressant-like effect in mice in forced swim test and tail suspension test, probably by interaction with adrenergic and dopaminergic system (dhingra & sharma, 2006) g. glabra aqueous extract 75-300 mg/kg, 7 days in vivo-oral administration to mice dose of 150 mg/kg significantly improved learning and memory of mice (parle, dhingra, & kulkarni, 2004) sedative activity (cho et al., 2010) antidepressive activity g. glabra aqueous extract 75-300 mg/kg in vivo-forced swim test and tail suspension test applied to mice antidepressant-like effect of liquorice extract seems to be mediated by increase of brain norepinephrine and dopamine, but not by increase of serotonin (dhingra & sharma, 2006) oestrogenic activity female wistar rats stimulation of creatine kinase specific activity (tamir, eizenberg, somjen, izrael, & vaya, 2001) liquorice root extract 25 μg/day, 2 weeks in vivo-oral administration to female rats increase in creatine kinase activity (tamir et al., 2000) liquiritigenin 2-10 μg/ml in vitro-mcf-7 and t47d cells induction of oestrogen responsive alkaline phosphatase activity in endometrial cancer cells, oestrogen responsive element luciferase in mcf-7 cells and tff1 mrna in t47d cells (somjen et al., 2004) isoliquiritigenin 0-0.04 mg/ml in vivo-intraperitoneal injection of female icr mice improvement of ivf rate (tung, shoyama, wada, & tanaka, 2014) skin effects glycyrrhizinic acid in vivo-double-blind clinical trial in human patients reduction of erythema, oedema, and itching scores (halder & richards, 2004) -in vitro-topical treatments in human patients during 4 weeks lighten hand solar lentigines (nerya et al., 2003) glycyrrhetinic acid; glabridin 0-120 μm in vitro-human keratinocyte culture prevention of oxidative dna fragmentation and activation of apoptosis-associated proteins in human keratinocyte (grippaudo & di russo, 2016) (continues) in vitro-vero cells in vivo-ducks stimulation of immune and antiviral effect against dhv (soufy et al., 2012) 0.1 μg/ml (extract) in vitro-human foreskin cell line protection of host cells against ev71 infection (kuo, chang, wang, & chiang, 2009) in vitro-vero cells protection against coronavirus (cinatl et al., 2003) 100 μg/ml (compound) in vitro-peripheral blood mononuclear cells inhibition of nonsyncytium-inducing variant of hiv replication (sasaki, takei, kobayashi, pollard, & suzuki, 2002) 400-1,600 mg/day (compound) in vitro-human immunodeficiency virus type 1 (hiv-1) p24 antigen inhibition of hiv-1 replication (hattori et al., 1989) 60 mg in vivo-oral administration to humans (ldl isolation) (carmeli & fogelman, 2009) licochalcone 2-20 μg/ml dpph, superoxide anion, lipid peroxidation, red blood cells inhibition of the microsomal lipid peroxidation (haraguchi, ishikawa, mizutani, tamura, & kinoshita, 1998) hepatoprotective activity liquorice aqueous extract 100-300 mg/kg 15 days in vivo-oral administration to wistar rats stimulation of the antioxidant enzymes and arrest of inflammatory cytokine production (huo, wang, liang, bao, & gu, 2011) g. glabra aqueous root extract 2 g/day, 2 months in vivo-humans alt and ast decrease (hajiaghamohammadi, ziaee, & samimi, 2012) 10, 30, 100 mg/kg 2005). these effects are associated with the presence of glycyrrhizin that helps to expel congestion in the upper respiratory tract and accelerates tracheal mucus secretion (v. sharma et al., 2016) . likewise, liquiritin apioside, an active compound reported in the methanolic extract of liquorice, has the ability to inhibit capsaicin, a compound that induces cough (kamei, nakamura, ichiki, & kubo, 2003) . the effect on sore throat has been compared with that of carbenoxolone, a glycyrrhetinic acid derivative with a steroid-like structure, which stimulates gastric mucus secretion (damle, 2014) . the use of g. glabra extract as antiulcerative is widely known. for the gastrointestinal system, it is used in gastric and duodenal ulcers (bardhan, cumberland, dixon, & holdsworth, 1978) , whereas for the treatment of spasmodic pains of chronic gastritis, it is employed as an adjuvant (armanini et al., 2002) . the benefits of g. glabra in the treatment of duodenal and peptic ulcers have been reported since the 1970s, and this traditional use is related to the presence of antiinflammatory saponins (krausse et al., 2004) . the major compound responsible for this activity is glycyrrhizin, which can raise the concentration of prostaglandins in the digestive tract, promoting stomach mucus secretion (jafarian & ghazvini, 2007) . in addition, liquorice prolongs the lifespan of stomach surface cells, demonstrating an antipepsin effect (ram, lachake, kaushik, & shreedhara, 2010) . furthermore, deglycyrrhizinated liquorice has shown some effects in the treatment of gastrointestinal ulcers, suggesting the presence of other active ingredients (zadeh, kor, & goftar, 2013) . indeed, carbenoxolone, a glycyrrhetinic acid analogue, is reported to inhibit two important enzymes for the metabolism of prostaglandin, 15-hydroxyprostaglandin dehydrogenase and δ 13 prostaglandin reductase, raising prostaglandin levels and leading to positive effects in clinical trials for gastric and duodenal ulcers (damle, 2014) . in fact, prostaglandins stimulate mucous secretion and cell proliferation leading to ulcer healing. nevertheless, the glycyrrhetic acid derivative carbenoxolone presents secondary effects such as the potential development of pseudo aldosteronism, which limits its use. in a clinical trial, bardhan et al. (1978) studied the effect of liquorice by oral administration in 96 patients with gastric ulcer. the patients were randomly allocated to the treatment either with deglycyrrhizinated liquorice or with placebo. however, after 4 weeks, no differences were observed between groups in the percentage of ulcer area reduction or clinical improvements (bardhan et al., 1978) . particular, glabridin, glabrol, glabrene, hispaglabridin a, hispaglabridin b, 40-methylglabridin, and 3-hydroxyglabrol, isolated from g. glabra, are responsible for this activity (l. . the mechanism behind this could be the decrease of bacterial gene expression, the inhibition of bacterial growth, and the reduction of bacterial toxin production (gupta et al., 2008; l. wang, yang, et al., 2015) . in 2014, s.-j. ahn, song, mah, cho, and kook (2014) (fukai et al., 2002a (fukai et al., , 2002b l. wang, yang, et al., 2015) . on the other hand, the ability to inactivate methicillin-resistant s. aureus (mrsa) by decreasing the expression of saer and hla, the key virulence genes of mrsa, have also been reported by different authors (fukai et al., 2002a (fukai et al., , 2002b l. wang, yang, et al., 2015) . it is also suggested that licochalcone e could be used for chemical synthesis of novel anti-s. aureus compounds, reducing the production of α-toxin in both methicillin-sensitive s. aureus and mrsa (l. . besides, α-haemolysin is an important exotoxin in the pathogenesis of s. aureus infections (berube & bubeck wardenburg, 2013) . such infections are associated with a broad spectrum of diseases, ranging from endocarditis to minor skin infections, toxinoses, and lethal pneumonia. liquiritigenin, one of the most active compounds of liquorice, demonstrated the capacity to prevent human lung cells (a549) from α-haemolysin-mediated injuries, by decreasing αhaemolysin production (l. . similarly, glabrin and glycyrrhetinic acid have shown antibacterial activity against s. aureus . different authors reported the antibacterial action of g. glabra against mycobacterium tuberculosis (gupta et al., 2008) , demonstrating that glabridin is the responsible compound for this activity, instead of hispaglabridin b . the antitubercular phenolic compounds were previously identified as licoisoflavone and licochalcone a (chakotiya, tanwar, srivastava, narula, & sharma, 2017) . in a mice lung infection model, g. glabra was therapeutically active against multidrug-resistant strain of p. aeruginosa (chakotiya et al., 2016) , and the hydro-alcoholic extract led to a reduction of the microbial load in the blood, mainly due to the presence of stigmasterol, ergosterol, licochalcone, and glabridin (chakotiya et al., 2017) . the activity of g. glabra against helicobacter pylori has been also reported, as mentioned in the previous subsection (krausse et al., 2004) . according to krausse et al. (2004) , the compounds responsible for this activity are glabridin and glabrene. cao et al. (2016) also reported that 18β-glycyrrhetinic acid significantly attenuated the gastritis infection caused by h. pylori. asha et al. (2013) found that the flavonoid glabridin exhibits activity against h. pylori whereas glycyrrhizin did not present activity even at a concentration of 250 μg/ml. these flavonoids also showed activity against h. pylori strains resistant to clarithromycin and amoxicillin (fukai et al., 2002a (fukai et al., , 2002b . the probable mechanism behind these action is the inhibition of the protein synthesis, dna gyrase, and dihydrofolate reductase (fukai et al., 2002a (fukai et al., , 2002b . moreover, the liquorice polysaccharides also present activity against porphyromonas gingivalis adhesion, which is of huge importance because no specific adhesion inhibitors have been described (chinsembu, 2016) . the antifungal activity of g. glabra is also detailed (sato, goto, nanjo, kawai, & murata, 2000) . sato et al. (2000) reported that the methanolic extract of liquorice presents fungicidal activity against arthrinium sacchari and chaetomium funicola, whereas glabridin was found to be the active compound responsible for the observed effects (sato et al., 2000) . in fact, isoflavonoids, such as glabridin, glabrol, and their derivatives, are responsible for the in vivo inhibition of mycobacterium smegmatis, shigella, salmonella, e. coli, s. mutans, and lactobacillus acidophilus (ajagannanavar et al., 2014) . recently, chandra and gunasekaran (2017) also proved the antifungal activity of crude methanolic extract of g. glabra against aspergillus niger. different authors reported that c. albicans is susceptible to liquorice extracts due to their richness in liquiritigenin, liquiritin, licochalcone a, and glabridin (chandra & gunasekaran, 2017 ; j. y. lee et al., 2009; singh et al., 2015) . nevertheless, according to karahan, avsar, ozyigit, and berber (2016) , the antimicrobial activity could be influenced by the environmental conditions that may affect the chemical compound contents and the biological activity. according to messier et al., licochalcone a and glabridin present a therapeutic potential against c. albicans oral infections, whereas glycyrrhizic acid had no effect (messier & grenier, 2011; moazeni et al., 2017) . fukui et al. (1988) isolated licoflavanone from the leaves of g. glabra, demonstrating its antimicrobial activity. indeed, chen et al. (1993) reported that licochalcone a is an antiparasitic compound with potential activity against human pathogenic protozoan leishmania species. the antiviral activity of g. glabra extracts against different viruses has been reported, including herpes simplex, varicella zoster, japanese encephalitis, influenza, and vesicular stomatitis virus (l. . different studies have demonstrated that two triterpenoids are responsible for the antiviral activity reported: glycyrrhizin and 18β-glycyrrhetinic acid (l. . these compounds have the ability to inhibit virus gene expression and replication, decreasing the adhesion force and stress and reducing hmgb1 binding to dna (l. . also, they can herpes simplex virus (hsv) is one of the most common viruses infecting humans and animals. during hsv infection, the cellular adhesion is increased, playing a key role in inflammatory response. w. huang et al. (2012) reported that the adhesion force and stress between the cerebral capillary vessel endothelial cells and the polymorphic nuclear leukocytes were amplified during hsv infection. glycyrrhizin stimulates the mouse defence system against hsv-1 infection (sekizawa, yanagi, & itoyama, 2001) . furthermore, glycyrrhizic acid was found to have a distinctive effect against kaposi sarcoma-associated herpes virus (kshv). it was proved that glycyrrhizic acid could terminate the latent infection of kshv when all current drugs are ineffective (damle, 2014) . also, glycyrrhizic acid down-regulates the expression of latency-associated nuclear antigen in b lymphocytes leading to natural cell death (apoptosis) of the kshv-infected cells (damle, 2014) . recently, the antiviral activity of glycyrrhizin against severe acute respiratory syndrome virus was evaluated (cinatl et al., 2003) . glycyrrhizin affects the cellular signalling pathways such as protein kinase c, casein kinase ii, and transcription factors, namely, activator protein 1 and nuclear factor κb (cinatl et al., 2003) . furthermore, glycyrrhizin and its aglycone, 18β the hepatoprotective activity of glycyrrhizin and 18β-glycyrrhetic acid by inhibition of free-radical generation and lipid peroxidation has been extensively reported (huo et al., 2011) . one of these studies indicated that the hydromethanolic root extract of g. glabra exhibits a significant protection against hepatotoxicity induced by carbon tetrachloride in the liver tissue of mice (v. sharma & agrawal, 2017) . the effects of liquorice on nonalcoholic fatty liver disease have also been investigated (hajiaghamohammadi et al., 2012) . according to rizzato et al. (2017) , glycyrrhizin and glycyrrhetinic acids prevent drug-induced liver injury and ensure the disruption of bile acid metabolism in humans. indeed glycyrrhetinic acid has been reported as anti-inflammatory and hepatoprotective compound (yin et al., 2017) , whereas glycyrrhizin, when compared with the placebo, induced a significant reduction in the serum aminotransferases and improved the liver histology (van rossum et al., 1998) . it has also been reported that the long-term use of glycyrrhizin prevents the development of hepatocellular carcinoma in chronic hepatitis c (van rossum et al., 1998) . in vitro studies have shown that glycyrrhizin modifies the intracellular transport and suppresses the hepatitis b virus surface antigen (sato et al., 1996) . in addition, it prevents the oxidative and hepatic damage caused by aflatoxins through increasing cyp1a1 and glutathione-stransferase activity, contributing to the anticarcinogenic activity by metabolic deactivation of the hepatotoxin (y. . mahmoud, hussein, hozayen, and abd el-twab (2017) reported that the treatment with 18β-glycyrrhetinic acid significantly reduced the serum enzymes, bilirubin, and proinflammatory cytokines in the liver, decreasing the expression of p450 e1. different studies suggest that the extract of g. glabra may be a potential supplemental source for different cancer treatments (c. s. lee, kim, lee, han, & lee, 2008; ohtsuki, oh-ishi, & nagata, 1992) . this activity is due to the 18β-glycyrrhetinic and glycyrrhizic acids that x. y. xiao et al., 2011) . the results indicated that licochalcone a inhibits gastric cancer cells growth in a dose-dependent way, by blocking cell cycle progression at the g2/m transition, inducing apoptosis. in addition, licochalcone a induced apoptosis by its effects on the expression of parp, caspase-3, bcl-2, and bax (x. y. xiao et al., 2011) . kanazawa et al. (2003) and jung et al. (2006) showed that isoliquiritigenin inhibits the cell growth by g2/m cell cycle arrest in breast and prostate tumour cells. different studies demonstrated that isoliquiritigenin suppresses pulmonary metastasis in mice (yamazaki et al., 2002) and human hepatoma cells (hsu, kuo, & lin, 2005) . apoptosis was primarily mediated through mitochondrial death cascade, as shown by loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-9. a possible explanation is that cell growth was arrested through up-regulation of p53 and p21 and down-regulation of cdk2, cyclin e, and e2f-1 while apoptosis was induced by increasing bax protein expression and activating caspase-7 (g. sharma et al., 2012) . glabridin exhibited antitumour properties in various human cancer cells . the results revealed that glabridin induced apoptosis in dose dependently in huh7 cells through caspase-3, caspase-8, and caspase-9 activation and parp cleavage (hsieh et al., 2016) . the effects of g. glabra on learning and memory were investigated in mice (dhingra & sharma, 2006; parle et al., 2004) . in 2004, parle et al. (2004) administered the extract of g. glabra orally to mice during 7 days at different concentrations (75-300 mg/kg). chakravarthi and avadhani (2013) and dhingra and sharma (2006) studied the effects of g. glabra root aqueous extract on the learning and memory of 1month-old male wistar albino mice at doses between 75 and 300 mg/kg, orally administered during six successive weeks. both studies demonstrated a significant improvement of learning and memory in mice, but the exact mechanism behind this action remains unknown (chakravarthi & avadhani, 2013; dhingra & sharma, 2006 ). these findings suggest a possible neuroprotective role of liquorice in the prevention of diseases such as alzheimer. the basis of alzheimer is the chronic inflammation of certain brain regions. thus, the antiinflammatory activity of liquorice might contribute to the observed memory-enhancing effects (yokota, nishio, kubota, & mizoguchi, 1998) . also, oxygen free radicals are implicated in the process of aging and could be responsible for the development of alzheimer's disease in elderly persons. the protective role of liquorice extract may be attributed to its antioxidant properties, resulting in reduced brain damage and improvement of neuronal function and memory. the combination of anti-inflammatory and antioxidant activities with neuroprotective role could lead to memory-enhancing effects. hasanein (2011) gamma-aminobutyric acid (gaba) is the major inhibitory neurotransmitter in the central nervous system, being gaba a receptors a target for anaesthetics and neuroleptic, anxiolytic, and anticonvulsant compounds . g. glabra acts as a modulator of gaba a receptors (hoffmann, beltrán, ziemba, hatt, & gisselmann, 2016) , being able to induce sedative and anxiolytic effects. glabridin was evaluated by examining gaba responses in acutely isolated dorsal raphe neurons of a rat . according to the authors, glabridin potentiated gaba-induced responses by positive modulation of gaba a receptors, exhibiting sedative and hypnotic effects . glabridin potentiation is not sensitive to flumazenil and uses a similar mechanism of the general anaesthetics involving the amino acids n265 and m286, which are located in the second and third transmembrane domains on the β-subunit of gaba a receptors (hanrahan, chebib, & johnston, 2011) . also, glabridin could contribute to the hypnotic effect, as it is able to cross the blood-brain barrier . liquorice extract may have potential therapeutic value for the treatment of depressive disorders. recent studies have shown that liquorice extract produces significant antidepressant effects in mice during forced swim test (fst) and tail suspension test (tst; dhingra & sharma, 2006) . in the fst model, mice were forced to swim in a restricted space and induced to a characteristic behaviour of immobility. this situation reflects a state of depression. the tst model also induces a state of immobility that is claimed to reproduce a condition similar to human depression. both models are widely used to screen antidepressant drugs. the precise mechanisms by which liquorice extract produced this effect are not completely understood. however, it is suggested that the extract may interact with α1-adrenoceptors and dopamine d2 receptors, increasing the levels of norepinephrine and dopamine in the mice brain (dhingra & sharma, 2006) . besides, p-cpa (a serotonin synthesis inhibitor) did not attenuate the antidepressant effect of liquorice extract, suggesting that this is not mediated by the serotonergic system. on the other hand, p-cpa reversed the antidepressant effect of fluoxetine, suggesting that fluoxetine acts in the serotonergic system. reserpine produces a significant depression by depleting biogenic amines in the brain of rodents. as liquorice extract reversed reserpine-induced depression, its antidepressant effect can be associated with the restoration of brain monoamines, such as norepinephrine and dopamine. since ancient times, the influences of liquorice on the action of cortisol, reduction of testosterone synthesis, and the influence on oestrogen activity are well known (armanini et al., 2002) . s. h. kim and park (2012) reported that isoflavones can influence sexual development and impair oestrous cycling and ovarian and hypothalamus and pituitary glands function (s. h. kim & park, 2012) . the oestrogenic effect of liquorice ethanolic extract could be explained by its agonist activity on mcf-7 breast cancer cells, being this action mediated by 18β-glycyrrhetinic acid (g. sharma et al., 2012) . glabridin is a common component of herbal remedies used for the treatment of menopausal symptoms, resulting in favourable outcomes similar to those of 17βoestradiol (su wei poh et al., 2015) . in concentrations between 2.5 and 25 μg per animal, glabridin induces similar effects to the administration of oestradiol in a concentration of 5 μg per animal. glabridin was found to be three to four times more active than 2′-omethylglabridin and 4′-o-methylglabridin (tamir et al., 2000) . moreover, according to tamir et al. (2001) , glabrene has a considerable oestrogenic activity. glabridin and glabrene are similar to 17βoestradiol in the stimulation of the specific activity of creatine kinase, although at higher concentrations, differing in the extension rate of action as well as in the interaction with other drugs. in human premenopausal bone cells, the response to 17β-oestradiol and glabridin (at a higher concentration) was higher than in postmenopausal cells, whereas glabrene (at a higher concentration) was more effective in postmenopausal cells (somjen et al., 2004) . isoliquiritigenin has a strong oestrogen-like activity, suggesting that this compound may be cyclized to liquiritigenin, which is an active flavonoid under physiological conditions (hajirahimkhan et al., 2013) . in vivo, the stimulatory effects of glabrene are similar to those of oestradiol (powers & setzer, 2015) . it is also interesting to observe that isoliquiritigenin and formononetin stimulate sperm during fertilization (tung et al., 2014) . this reveals that both phytoestrogens may be useful therapeutic agents for infertility treatments (tung, shoyama, wada, & tanaka, 2015) . zamansoltani, nassiri-asl, sarookhani, jahani-hashemi, and zangivand (2009) reported that the alcoholic extract of g. glabra has antiandrogenic effects probably by increasing the testosterone metabolism, down-regulating androgen receptors, or activating oestrogenic receptors. the main skin benefits reported for g. glabra are based on the antioxidant and anti-inflammatory activities as well as on the ultraviolet (uv) protection (halder & richards, 2004) . saeedi, morteza-semnani, and ghoreishi (2003) reported the use of liquorice mainly for skin eruptions, including dermatitis, eczema, pruritus, and cysts. in particular, the g. glabra flavonoids present depigmenting capabilities and tyrosinase inhibition effects (solano, briganti, picardo, & ghanem, 2006) . the presence of an α-keto group in flavonoids is responsible for this activity (y. j. kim & uyama, 2005; parvez et al., 2007) . castangia et al. (2015) have reported the skin protective effects of liquorice against damage from oxidative stress. according to the authors, liquorice extract can scavenge dpph free radicals with an inhibition of 80% and protect fibroblasts against oxidative stress (castangia et al., 2015) . nevertheless, when evaluated in the isolated form, glycyrrhizin showed a poor antioxidant activity, being not able to efficiently counteract the oxidative effect (castangia et al., 2015) . tyrosinase is essential for skin pigmentation due to its role in melanin biosynthesis (solano et al., 2006) . the use of tyrosinase inhibitors is important in the cosmetic and medicinal industries, due to their preventive effect on pigmentation disorders such as melasma, age spots, and sites of actinic damage (nerya et al., 2003) . alternatively, tyrosinase inhibitors may be targets for developing medicines to treat hypopigmentation-related problems, such as albinism and piebaldism (y. j. kim & uyama, 2005) . in particular, glabridin, glabrene, isoliquiritigenin, licochalcone a, and liquiritin have been reported as g. glabra compounds able to inhibit the tyrosinase activity (ebanks, wickett, & boissy, 2009; nerya et al., 2003) . recently, grippaudo and di russo (2016) described the effects of the topical application of glycyrrhetinic acid combined with fractional carbon dioxide laser for the benign treatment of hand hyperpigmentation during 4 weeks. likewise, the treatment of human keratinocytes with 18βglycyrrhetinic acid and glabridin was documented to directly and indirectly prevent dna damage, avoiding the apoptosis activation caused by uv b radiation (veratti et al., 2011) . indeed, yokota et al. (1998) described that glabridin inhibits tyrosinase activity, melanogenesis, and skin inflammation. besides, glabrene acts as a tyrosinase inhibitor, preventing the formation of melanin in melanocytes, probably acting as skin-lightening agent. saeedi et al. (2003) liquorice has been traditionally used as a sweetener due to its taste, (tian, liu, zhen, & tong, 2013; tong, xie, rong, zhou, & meng, 2015) . according to bahmani et al. (2014) , liquorice can reduce diabetes symptoms, such as polydipsia and frequent urination, but cannot reduce blood glucose. takii et al. (2001) suggested that glycyrrhizin has an antidiabetic effect in noninsulin-dependent diabetes mice model, reducing the postprandial blood glucose rise. licochalcone a is the most promising one, inhibiting in vitro the growth of chloroquine-susceptible and chloroquine-resistant plasmodium falciparum strains (chen et al., 1994) . glabridin also showed in vitro activity against this parasite, probably by an induction of oxidative stress, mainly through the generation of reactive oxygen and nitrogen species that lead to apoptosis (cheema et al., 2014) . it is well known that myocardial ischaemia is one of the principal diseases in the western world. this disease occurs through occlusion or blockage of coronary arteries, resulting in myocardial cell death. however, the reperfusion produces the salvage of ischaemic tissue but also contributes to the myocardial cellular injury. the pretreatment with g. glabra significantly attenuates the ischaemic reperfusion, through an improvement of the heart antioxidant status, a positive modulation of the perturbed haemodynamic, and a recovery of left ventricular contractile function, along with histological salvage (di paola et al., 2009; ojha, golechha, kumari, bhatia, & arya, 2013) . in particular, glycyrrhizic acid induced protection against myocardial ischaemia in rats, probably due to its antioxidant potential (ojha et al., 2013) . similarly, nakagawa, kishida, arai, nishiyama, and mae (2004) demonstrated that g. glabra is safe for cardiomyocytes in a long-term administration. the extract of g. glabra has been used in the treatment of low bone mass, osteoporosis, fractures, bone defects, osteomalacia, osteogenesis imperfecta, bone disease, and periodontal diseases . rajesh (2004) described the inhibitory effect on bone reabsorption of g. glabra, whereas choi (2011) reported that glabridin is responsible for this activity. mitochondrial dysfunction, especially respiratory chain disruption, is responsible for aging-related bone diseases. hence, the target of glabridin is the reduction of mitochondrial dysfunction induced during aging and the prevention of osteoblast damage in osteoporotic patients (choi, 2011) . study on mice demonstrated that g. glabra, particularly glabridin, when integrated in a dietary supplement, could reduce the susceptibility of low-density lipoprotein (ldl) to oxidation and the atherosclerotic lesion area (fuhrman & aviram, 2001; grassi, desideri, & ferri, 2010) . these results could be related to the absorption and binding of glabridin to the ldl and a subsequent protection of the ldl from oxidation (fuhrman et al., 1997) . the methanolic extract of g. glabra rhizomes, at a dose of 150 mg/kg, has antiarthritic activity in male rats by inhibition of leukocyte migration, autoantigen production, and exhibition of antiproteinase activity (choudhary, kumar, malhotra, & singh, 2015) . also, mishra, bstia, mishra, chowdary, and patra (2001) reported that a combined formulation of g. glabra and boswellia serrata (1:1) had a significant synergistic action on arthritis. shin et al. (2007) studied the antiallergic effects, namely, the antiscratching behaviour and the ige production inhibitory activity, of glycyrrhizin, 18β-glycyrrhetinic acid, isoliquiritin, and liquiritigenin in dermatitis and asthma (shin et al., 2007) . in particular, 18β different adverse side effects were reported for high doses of g. glabra such as hypertension, hypokalaemia, or fluid retention (omar et al., 2012) . the exposure to high levels of glycyrrhizin can produce hypermineralocorticoid-like effects. glycyrrhetic acid and liquorice saponins can inhibit 11-β-hydroxysteroid dehydrogenase enzyme, leading to a cortisol-induced mineralocorticoid effect and a consequent tendency to the elevation of sodium and reduction of potassium levels (isbrucker & burdock, 2006) . for example, in 2010, a 34-yearold woman was suspected to have suffered a lethal acute intoxication from eating liquorice over a period of several months (albermann et al., 2010) . albermann et al. associated the effects with the potential mineralocorticoid action of glycyrrhizin and its metabolite, glycyrrhetic acid, and quantified by liquid chromatography-tandem mass spectrometry these compounds in the blood. nevertheless, only traces of glycyrrhetic acid had been found in the blood and stomach content of the deceased woman, which means that the possibility of acute lethal glycyrrhetic acid intoxication could be eliminated (albermann et al., 2010) . based on in vivo assays and clinical evidence, the amount of liquorice ingested daily by patients with mineralocorticoid excess syndromes appears to vary over a wide range (1.5-250 g/day ; isbrucker & burdock, 2006) . in addition to hypertension, patients may experithus, side effects remain an area of potential future study. this review not only details and explains the traditional use of this plant but also highlights its potential uses for other industries, such as cosmetic or pharmaceutical ones. more clinical trials should be performed to provide scientific basis for new uses. in conclusion, although evidence has grown in the past decade, there is still a need to conduct further robust double-blind randomized controlled trial about g. glabra. there is also an immense scope to explore different combinations of liquorice preparations in a wide range of disorders. anti-obesity effects of glabridin-rich supercritical carbon dioxide extract of licorice in highfat-fed obese mice determination of optimal concentration of deglycyrrhizinated licorice root extract for preventing dental caries using a bacterial model system effect of aqueous and alcoholic licorice (glycyrrhiza glabra) root extract against streptococcus mutans and lactobacillus acidophilus in comparison to chlorhexidine: an in vitro study determination of glycyrrhetic acid after consumption of liquorice and application to a fatality history of the endocrine effects of licorice in vitro anti-helicobacter pylori activity of a flavonoid rich extract of glycyrrhiza glabra and 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aquo-alchoholic extract of glycyrrhiza glabra against pseudomonas aeruginosa in mice lung infection model beneficial effect of aqueous root extract of glycyrrhiza glabra on learning and memory using different behavioral models: an experimental study screening of the phytochemical, antimicrobial and antioxidant activity of glycyrrhiza glabra root extract glabridin induces oxidative stress mediated apoptosis like cell death of malaria parasite plasmodium falciparum licochalcone a, a novel antiparasitic agent with potent activity against human pathogenic protozoan species of leishmania licochalcone a, a new antimalarial agent, inhibits in vitro growth of the human malaria parasite plasmodium falciparum and protects mice from p. yoelii infection plants and other natural products used in the management of oral infections and improvement of oral health hypnotic effects and binding studies for gabaa and 5-ht2c receptors of traditional medicinal plants used in asia for insomnia glabridin protects osteoblastic mc3t3-e1 cells against antimycin a induced cytotoxicity medicinal plants with potential anti-arthritic activity chemical composition and antimicrobial activities of the essential oil from glycyrrhiza glabra leaves glycyrrhizin, an active component of liquorice roots, and replication of sars-associated coronavirus glycyrrhiza glabra (liquorice)-a potent medicinal herb effects of glycyrrhizin in a mouse model of lung adenocarcinoma antidepressant-like activity of glycyrrhiza glabra l. in mouse models of immobility tests. progress in neuro-psychopharmacology and biological psychiatry protective effects of glycyrrhizin in a gut hypoxia (ischemia)-reoxygenation (reperfusion) model. intensive care medicine mechanisms regulating skin pigmentation: the rise and fall of complexion coloration evaluation of certain food additives a history of the therapeutic use of liquorice in europe flavonoids protect ldl from oxidation and attenuate atherosclerosis licorice extract and its major polyphenol glabridin protect low-density lipoprotein against lipid peroxidation: in vitro and ex vivo studies in humans and in atherosclerotic apolipoprotein e-deficient mice anti-helicobacter pylori flavonoids from licorice extract antimicrobial activity of licorice flavonoids against methicillin-resistant staphylococcus aureus two antimicrobial flavanones from the leaves of glycyrrhiza glabra flavonoids: antioxidants against atherosclerosis effects of topical application of β-resorcinol and glycyrrhetinic acid monotherapy and in combination with fractional co 2 laser treatment for benign hand hyperpigmentation treatment antimicrobial potential of glycyrrhiza glabra roots the efficacy of licorice root extract in decreasing transaminase activities in non-alcoholic fatty liver disease: a randomized controlled clinical trial evaluation of estrogenic activity of licorice species in comparison with hops used in botanicals for menopausal symptoms topical agents used in the management of hyperpigmentation flavonoid modulation of gaba (a) receptors antioxidative and superoxide scavenging activities of retrochalcones in glycyrrhiza inflata pharmacological studies of glycyrrhiza glabra: a review chemopreventive effect of 18β-glycyrrhetinic acid via modulation of inflammatory markers and induction of apoptosis in human hepatoma cell line (hepg2) glabridin as a major active isoflavan from glycyrrhiza glabra (licorice) reverses learning and memory deficits in diabetic rats preliminary evidence for inhibitory effect of glycyrrhizin on hiv replication in patients with aids economic importance of licorice characterization of g. glabra and g. bucharica collected in tajikistan estimation of dietary intake of ochratoxin a from liquorice confectionery potentiating effect of glabridin from glycyrrhiza glabra on gaba a receptors glabridin induces apoptosis and autophagy through jnk1/2 pathway in human hepatoma cells isoliquiritigenin induces apoptosis and cell cycle arrest through p53-dependent pathway in hep g2 cells glycyrrhizin inhibits porcine epidemic diarrhea virus infection and attenuates the proinflammatory responses by inhibition of high mobility group box-1 protein inhibition of intercellular adhesion in herpes simplex virus infection by glycyrrhizin 18α-glycyrrhetinic acid induces apoptosis of hl-60 human leukemia cells through caspases-and mitochondria-dependent signaling pathways hepatoprotective and antioxidant effects of licorice extract against ccl(4)-induced oxidative damage in rats risk and safety assessment on the consumption of licorice root (glycyrrhiza sp.), its extract and powder as a food ingredient, with emphasis on the pharmacology and toxicology of glycyrrhizin in vitro susceptibility of helicobacter pylori to licorice extract glabridin inhibits cancer stem cell-like properties of human breast cancer cells: an epigenetic regulation of mir-148a/smad2 signaling. molecular carcinogenesis potentiating effect of glabridin on gabaa receptor-mediated responses in dorsal raphe neurons isoliquiritigenin induces apoptosis by depolarizing mitochondrial membranes in prostate cancer cells role of glucocorticoid in the development of glycyrrhizin-induced hypertension. clinical and experimental hypertension antitussive principles of glycyrrhizae radix, a main component of the kampo preparations bakumondo-to (mai-men-dong-tang) isoliquiritigenin inhibits the growth of prostate cancer antimicrobial and antioxidant activities of medicinal plant glycyrrhiza glabra var. glandulifera from different habitats 18β-glycyrrhetinic acid, the major bioactive component of glycyrrhizae radix, attenuates airway inflammation by modulating th2 cytokines, gata-3, stat6, and foxp3 transcription factors in an asthmatic mouse model effects of phytoestrogen on sexual development tyrosinase inhibitors from natural and synthetic sources: structure, inhibition mechanism and perspective for the future intestinal absorption and biliary elimination of glycyrrhizic acid diethyl ester in rats. drug design in vitro anti-helicobacter pylori activity of extractum liquiritiae, glycyrrhizin and its metabolites biphasic calcium phosphate-casein bone graft fortified with cassia occidentalis for bone tissue engineering and regeneration water extract of glycyrrhiza uralensis inhibited enterovirus 71 in a human foreskin fibroblast cell line 18β-glycyrrhetinic acid induces apoptotic cell death in siha cells and exhibits a synergistic effect against antibiotic anti-cancer drug toxicity liquiritigenin, a licorice flavonoid, helps mice resist disseminated candidiasis due to candida albicans by th1 immune response, whereas liquiritin, its glycoside form, does not synthesis and anticancer activities of glycyrrhetinic acid derivatives metabolomics analysis to evaluate the anti-inflammatory effects of polyphenols: glabridin reversed metabolism change caused by lps in raw 264.7 cells methotrexate hepatotoxicity is associated with oxidative stress, and down-regulation of ppargamma and nrf2: protective effect of 18β-glycyrrhetinic acid antithrombotic effect of glycyrrhizin, a plantderived thrombin inhibitor effect of licorice compounds licochalcone a, glabridin and glycyrrhizic acid on growth and virulence properties of candida albicans glycyrrhizin exerts antioxidative effects in h5n1 influenza a virus-infected cells and inhibits virus replication and proinflammatory gene expression antiarthritic activity of glycyrrhiza glabra, boswellia serrata and their synergistic activity in combined formulation studied in freund's adjuvant induced arthritic rats evaluation of immunomodulatory activity of glycyrhiza glabra l. roots in combination with zing glabridin triggers over-expression of mca1 and nuc1 genes in candida glabrata: is it an apoptosis inducer a novel process for extraction of natural sweetener from licorice (glycyrrhiza glabra) roots. separation and purification technology licorice flavonoids suppress abdominal fat accumulation and increase in blood glucose level in obese diabetic kk-a(y) mice glabrene and isoliquiritigenin as tyrosinase inhibitors from licorice roots the stimulatory and inhibitory effects of glycyrrhizin and a glycyrrhetinic acid derivative on phosphorylation of lipocortin i by a-kinase in vitro glycyrrhiza glabra protects from myocardial ischemia-reperfusion injury by improving hemodynamic, biochemical, histopathological and ventricular function licorice abuse: time to send a warning message antibacterial effects of glycyrrhetinic acid and its derivatives on staphylococcus aureus licochalcone-a induces intrinsic and extrinsic apoptosis via erk1/2 and p38 phosphorylation-mediated trail expression in head and neck squamous carcinoma fadu cells memory-strengthening activity of glycyrrhiza glabra in exteroceptive and interoceptive behavioral models naturally occurring tyrosinase inhibitors: mechanism and applications in skin health, cosmetics and agriculture industries the pharmacokinetics of glycyrrhizic acid evaluated by physiologically based pharmacokinetic modeling a molecular docking study of phytochemical estrogen mimics from dietary herbal supplements mechanism of anti-inflammatory action of liquorice extract and glycyrrhizin protective activity of glycyrrhiza glabra linn. on carbon tetrachloride-induced peroxidative damage formulation and evaluation of floating tablets of liquorice extract a new exploration of licorice metabolome anti-hiv activity of indian medicinal plants the treatment of atopic dermatitis with licorice gel effect of glycyrrhizin, an active component of licorice roots, on hiv replication in cultures of peripheral blood mononuclear cells from hiv-seropositive patients therapeutic basis of glycyrrhizin on chronic hepatitis b antifungal activity of plant extracts against arthrinium sacchari and chaetomium funicola hair growth stimulating effect and phytochemical evaluation of hydro-alcoholic extract of glycyrrhiza glabra glycyrrhizin increases survival of mice with herpes simplex encephalitis some effects of glycyrrhiza glabra (liquorice) roots extract on male rats 18β-glycyrrhetinic acid induces apoptosis through modulation of akt/foxo3a/bim pathway in human breast cancer mcf-7 cells in vivo antioxidant and hepatoprotective potential of glycyrrhiza glabra extract on carbon tetra chloride (ccl 4 ) induced oxidative-stress mediated hepatotoxicity assessment of median lethal dose and anti-mutagenic effects of glycyrrhiza glabra root extract against chemically induced micronucleus formation in swiss albino mice glycyrrhiza glabra: chemistry and pharmacological activity in vitro and in vivo antiallergic effects of glycyrrhiza glabra and its components phytochemistry and biological properties of glabridin a polyphenolic flavonoid glabridin: oxidative stress response in multidrug-resistant staphylococcus aureus phytocomplexes from liquorice (glycyrrhiza glabra l.) leaves-chemical characterization and evaluation of their antioxidant, anti-genotoxic and anti-inflammatory activity hypopigmenting agents: an updated review on biological, chemical and clinical aspects estrogenic activity of glabridin and glabrene from licorice roots on human osteoblasts and prepubertal rat skeletal tissues antiviral and immune stimulant activities of glycyrrhizin against duck hepatitis virus estrogenicity of glabridin in ishikawa cells antidiabetic effect of glycyrrhizin in genetically diabetic kk-ay mice estrogen-like activity of glabrene and other constituents isolated from licorice root estrogenic and antiproliferative properties of glabridin from licorice in human breast cancer cells successful treatment of latent autoimmune diabetes in adults with traditional chinese medicine: a case report detection of consensuses and treatment principles of diabetic nephropathy in traditional chinese medicine: a new approach improved in vitro fertilization ability of mouse sperm caused by the addition of licorice extract to the preincubation medium two activators of in vitro fertilization in mice from licorice review article: glycyrrhizin as a potential treatment for chronic hepatitis c pharmacokinetics of intravenous glycyrrhizin after single and multiple doses in patients with chronic hepatitis c infection phytochemical screening and determination of anti-bacterial and anti-oxidant potential of glycyrrhiza glabra root extracts 18β-glycyrrhetinic acid and glabridin prevent oxidative dna fragmentation in uvb-irradiated human keratinocyte cultures the antiviral and antimicrobial activities of licorice, a widely-used chinese herb metabolites identification of bioactive licorice compounds in rats 18β-glycyrrhetinic acid exhibits potent antitumor effects against colorectal cancer via inhibition of cell proliferation and migration liquorice, a unique "guide drug" of traditional chinese medicine: a review of its role in drug interactions glycyrrhizin inhibits lps-induced inflammatory mediator production in endometrial epithelial cells hypoglycemic effects of glabridin, a polyphenolic flavonoid from licorice, in an animal model of diabetes mellitus licochalcone a inhibits growth of gastric cancer cells by arresting cell cycle progression and inducing apoptosis 18β-glycyrrhetinic acid ameliorates acute propionibacterium acnes-induced liver injury through inhibition of macrophage inflammatory protein-1α isoliquiritigenin suppresses pulmonary metastasis of mouse renal cell carcinoma the anti-inflammatory activity of licorice, a widely used chinese herb protective effects of hepatocyte-specific glycyrrhetic derivatives against carbon tetrachloride-induced liver damage in mice efficacy of intravenous glycyrrhizin in the early stage of acute onset autoimmune hepatitis glycyrrhetinic acid attenuates lipopolysaccharide-induced fulminant hepatic failure in d-galactosamine-sensitized mice by up-regulating expression of interleukin-1 receptor the inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation antiinflammatory activities of licorice extract and its active compounds, glycyrrhizic acid, liquiritin and liquiritigenin, in bv2 cells and mice liver licochalcone-e induces caspase-dependent death of human pharyngeal squamous carcinoma cells through the extrinsic and intrinsic apoptotic signaling pathways licorice (glycyrrhiza glabra linn) as a valuable medicinal plant antiandrogenic activities of glycyrrhiza glabra in male rats glycyrrhizin administration ameliorates coxsackievirus b3-induced myocarditis in mice liquorice (glycyrrhiza glabra): a phytochemical and pharmacological review the authors declare that they have no conflict of interest. key: cord-303879-3hug5hj3 authors: cushnie, t.p. tim; lamb, andrew j. title: antimicrobial activity of flavonoids date: 2005-10-19 journal: int j antimicrob agents doi: 10.1016/j.ijantimicag.2005.09.002 sha: doc_id: 303879 cord_uid: 3hug5hj3 flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. for centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to interand intra-assay variation in susceptibility testing. however, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. in addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. the activity of quercetin, for example, has been at least partially attributed to inhibition of dna gyrase. it has also been proposed that sophoraflavone g and (−)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones a and c inhibit energy metabolism. other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2′-trihydroxy-5′-methylchalcone and lonchocarpol a. these compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents. resistance to antimicrobial agents has become an increasingly important and pressing global problem. of the 2 million people who acquire bacterial infections in us hospitals each year, 70% of cases now involve strains that are resistant to at least one drug [1] . a major cause for concern in the uk is methicillin-resistant staphylococcus aureus (mrsa), which was at low levels a decade ago but now accounts for ca. 50% of all s. aureus isolates [2] . substantial investment and research in the field of anti-infectives are now desperately needed if a public health crisis is to be averted. structural modification of antimicrobial drugs to which resistance has developed has proven to be an effective means of extending the lifespan of antifungal agents such as the azoles [3] , antiviral agents such as the non-nucleoside reverse transcriptase inhibitors [4] , and various antibacterial agents including ␤-lactams and quinolones [5] . it is not surprising then, that in response to antimicrobial resistance, major pharmaceutical companies have tended to concentrate their efforts on improving antimicrobial agents in established classes [6] . however, with the portfolio of chemotherapeutics currently available, it has been acknowledged that researchers are getting close to the end game in terms of parent structure alterations. a call has therefore been made for the development of new classes of drug that work on different target sites to those in current use [7, 8] . rational drug design does not always yield effective antimicrobials. in the past, potent enzyme inhibitors have been successfully designed and synthesised but they had only modest antibacterial activity, probably owing to the complex issue of drug uptake by cells. broad empirical screening of chemical entities for antimicrobial activity represents an alternative strategy for the development of novel drugs. natural products have been a particularly rich source of anti-infective agents, yielding, for example, the penicillins in 1940, the tetracyclines in 1948 and the glycopeptides in 1955 [9] . the following review will examine the antimicrobial activity of flavonoids, a class of natural products possessing a diverse range of pharmacological properties. compounds with antifungal, antiviral and antibacterial activity will each be discussed in turn, with particular emphasis on those flavonoids with antibacterial activity. flavonoids are ubiquitous in photosynthesising cells and therefore occur widely in the plant kingdom [10] . they are found in fruit, vegetables, nuts, seeds, stems and flowers as well as tea, wine [11] , propolis and honey [12] , and represent a common constituent of the human diet [13] . in the us, the daily dietary intake of mixed flavonoids is estimated to be in the range 500-1000 mg, but this figure can be as high as several grams for people supplementing their diets with flavonoids or flavonoid-containing herbal preparations [14] . the function of flavonoids in flowers is to provide colours attractive to plant pollinators [11, 15] . in leaves, these compounds are increasingly believed to promote physiological survival of the plant, protecting it from, for example, fungal pathogens and uv-b radiation [13, 15] . in addition, flavonoids are involved in photosensitisation, energy transfer, the actions of plant growth hormones and growth regulators, control of respiration and photosynthesis, morphogenesis and sex determination [11, 13] . the basic structural feature of flavonoid compounds is the 2-phenyl-benzo[␣]pyrane or flavane nucleus, which consists of two benzene rings (a and b) linked through a heterocyclic pyrane ring (c) (fig. 1 ) [16] . flavonoids can be classified according to biosynthetic origin. some classes, for example chalcones, flavanones, flavan-3-ols and flavan-3,4-diols, are both intermediates in biosynthesis as well as end products that can accumulate in plant tissues. other classes are only known as end products of biosynthesis, for example anthocyanidins, proanthocyanidins, flavones and flavonols. two additional classes of flavonoid are those in which the 2-phenyl side chain of flavanone isomerises to the 3 position, giving rise to isoflavones and related isoflavonoids. the neoflavonoid is formed through further isomerisation to the 4 position [13] . structures of the major classes of flavonoids are given in fig. 2 . the structures of specific compounds within these classes that possess antimicrobial activity and that are discussed in the present review are summarised in table 1 . individual flavonoids may be assigned names in three different ways. trivial names are employed extensively and sometimes indicate flavonoid class or plant source. for example, names ending in 'inidin' can denote an anthocyanidin, names ending in 'etin' generally denote a flavonol, and compounds tricin and hypolaetin have been extracted from plants belonging to the genera triticum and hypolaena. flavonoids may also be named in a semi-systematic manner based on trivial names such as flavone or chalcone as the parent structure, e.g. 3,5,7,3 4 -pentahydroxyflavone or 3,3 ,4 ,5,7-pentahydroxyflavone. lastly, flavonoids may be given systematic chemical names, e.g. 3,4-dihydro-2-phenyl-2h-1-benzopyran for flavan, but this method is cumbersome and rarely used [13] . in the present review, trivial names will be used wherever possible. increasingly, flavonoids are becoming the subject of medical research. they have been reported to possess many useful properties, including anti-inflammatory activity, oestrogenic activity, enzyme inhibition, antimicrobial activity [10, 13] , antiallergic activity, antioxidant activity [11] , vascular activity and cytotoxic antitumour activity [15] . for a group of compounds of relatively homogeneous structure, the flavonoids inhibit a perplexing number and variety of eukaryotic enzymes and have a tremendously wide range of activities. in the case of enzyme inhibition, this has been postulated to be due to the interaction of enzymes with different parts of the flavonoid molecule, e.g. carbohydrate, phenyl ring, phenol and benzopyrone ring [10] . several reviews have been written on the interaction between flavonoids and mammalian cells, including comprehensive articles by harborne and williams [15] and middleton et al. [20] . an extensive review on the biochemistry and medical significance of flavonoids has also recently been produced by havsteen [21] . for centuries, preparations that contain flavonoids as the principal physiologically active constituents have been used by physicians and lay healers in attempts to treat human diseases [10] . for example, the plant tagetes minuta (containing quercetagetin-7-arabinosyl-galactoside) has been used extensively in argentine folk medicine to treat infectious disease [22] . the healing properties of propolis (or 'tzori' in hebrew) are referred to throughout the old testament [23] , and this balm was prescribed by hippocrates (460-377 bc) in ancient greece for the treatment of sores and ulcers [24] . [17, 18] , isoflavones [10] , chalcones [13, 19] , flavanones [10, 13] , flavones [10] , flavonols [10] , flavanon-3-ols [13] , anthocyanidins [13, 20] , flavan-3-ols [10, 13] , proanthocyanidins (occur as dimers, trimers, tetramers and pentamers; r = 0, 1, 2 or 3 flavan-3-ol structures) [13] , flavans [13] , flavan-3,4-diols [13] and dihydrochalcones [13] . table 1 a summary of the structures of antimicrobial flavonoids discussed within the present review article (compiled from the handbook of natural flavonoids [13] and individual research papers) substituents at carbon position: 2 3 4 5 6 7 8 2 3 4 5 6 flavones and their glycosides acacetin galangin flavan-3,4-diols and anthocyanidins leucocyanidin the antimicrobial properties of propolis have been attributed to its high flavonoid content and in particular the presence of the flavonoids galangin and pinocembrin [12, [25] [26] [27] . huangchin (scutellaria baicalensis) is yet another example. this herbal medicine has been used systemically and topically for thousands of years in china for the treatment of periodontal abscesses and infected oral wounds. the flavone baicalein is reported to be largely responsible for this plant's antimicrobial effects [28] . a oh r3 oh r3 oh naringenin oh oh oh naringin oh or7 oh pinocembrin oh oh ponciretin oh oh och 3 sophoraflavanone g oh oh r10 oh oh 3-methyleneflavanone ch 2 5,7,4 -trihydroxy-8-methyl-6-(3-methyl-[2butenyl])-(2s)-flavanone o h r 3 o h c h 3 o h chalcones licochalcone a r11 oh och 3 o h licochalcone c oh r3 och 3 o h 2,4,2 -trihydroxychalcone oh oh o h 2,4,2 -trihydroxy-5 -methylchalcone oh oh ch 3 o h -oh oh oh oh oh oh pelargonidin chloride cl oh oh oh flavans 6,4 -dichloroflavan c l c l 7-hydroxy-3 ,4 -(methylenedioxy)flavan o h # # r1 it has been suggested that because flavonoids are widely distributed in edible plants and beverages and have previously been used in traditional medicine, they are likely to have minimal toxicity. however, this family of compounds has a diverse range of activities in mammalian cells [14, 20] and in vivo confirmation of their side effects would be necessary for a full evaluation of their practical usefulness in the field of modern medicine [29] . given that the selectivity of flavonoids for eukaryotic enzymes appears to vary from compound to compound [15, 20] , such a study would need to assess the toxicity of these phytochemicals on an individual basis. owing to the widespread ability of flavonoids to inhibit spore germination of plant pathogens, they have been proposed for use against fungal pathogens of man [15] . a new prenylated flavanone recently isolated from the shrub eysenhardtia texana has been identified as 5,7,4 -trihydroxy-8methyl-6-(3-methyl-[2-butenyl])-(2s)-flavanone and shown to possess activity against the opportunistic pathogen candida albicans [30] . the flavonoid 7-hydroxy-3 ,4 -(methylenedioxy)flavan, isolated from terminalia bellerica fruit rind, has also been shown to possess activity against c. albicans [31] . two new flavones from artemisia giraldi, identified as 6,7,4 -trihydroxy-3 ,5 -dimethoxyflavone and 5,5dihydroxy-8,2 ,4 -trimethoxyflavone, together with 5,7,4 -trihydroxy-3 ,5 -dimethoxyflavone have been reported to exhibit activity against aspergillus flavus [32] , a species of fungi that causes invasive disease in immunosuppressed patients [33] . the activity of propolis against dermatophytes and candida spp. has been attributed at least partially to its high flavonoid content [34] . galangin, a flavonol commonly found in propolis samples [24] , has been shown to have inhibitory activity against aspergillus tamarii, a. flavus, cladosporium sphaerospermum, penicillium digitatum and penicillium italicum [35] . a recent area of research that is of particular interest is the apparent inhibitory activity of some flavonoids against human immunodeficiency virus (hiv). to date, most if not all investigations have involved work with the pandemic hiv-1 strain and its enzymes. in vitro studies have shown that baicalin inhibits hiv-1 infection and replication. inhibition of hiv-1 entry into cells expressing cd4 and chemokine co-receptors [36] , and antagonism of hiv-1 reverse transcriptase [37] by the flavone o-glycoside have been demonstrated by li and colleagues. baicalein [38] , robustaflavone and hinokiflavone [39] have also been shown to inhibit hiv-1 reverse transcriptase, as have several catechins, but catechins inhibit other dna polymerases and their interaction with the hiv-1 enzyme is therefore thought to be non-specific in nature [40] . in addition, it has been demonstrated that several flavonoids, including demethylated gardenin a and 3,2 -dihydroxyflavone, inhibit hiv-1 proteinase [41] . robinetin, myricetin, baicalein, quercetagetin [42] and quercetin 3-o-(2 -galloyl)-␣-l-arabinopyranoside [43] inhibit hiv-1 integrase, although there are concerns that hiv enzyme inhibition by quercetagetin and myricetin is non-specific [44] . it has also been reported that the flavonoids chrysin, acacetin and apigenin prevent hiv-1 activation via a novel mechanism that probably involves inhibition of viral transcription [45] . interestingly, in a study by hu and colleagues, chrysin was reported to have the highest therapeutic index of 21 natural and 13 synthetic flavonoids against hiv-1 [46] . several research groups have investigated the relationship between flavonoid structure and inhibitory activity against hiv-1 and its enzymes [39, 41, 42, 44, 46] . furthermore, at least two groups have proposed mechanisms of action for hiv-1 enzyme inhibition [41, 42] . flavonoids also have inhibitory activity against a variety of other viruses. for example, selway reports that quercetin, morin, rutin, dihydroquercetin, dihydrofisetin, leucocyanidin, pelargonidin chloride and catechin possess activity against up to seven types of virus, including herpes simplex virus (hsv), respiratory syncytial virus, poliovirus and sindbis virus [11, 47] . proposed antiviral mechanisms of action include inhibition of viral polymerase and binding of viral nucleic acid or viral capsid proteins [47] . in addition to the flavonoids mentioned above, three proanthocyanidins from pavetta owariensis (with structural similarity to proanthocyanidin a2 and cinnamtannin b1 and b2) have been shown to have activity against hsv and coxsackie b virus [48, 49] . it has also been demonstrated that two of the flavonoids found in propolis, chrysin and kaempferol, inhibit viral replication of hsv, human coronavirus and rotavirus [50] . more recently, the flavonol galangin has been reported to have significant antiviral activity against hsv and coxsackie b virus [51] . although naturally occurring flavonoids with antiviral activity have been recognised since the 1940s, it is only in the last 25 years that attempts have been made to synthetically modify flavonoids for improved antiviral activity. one such synthesised compound is 6,4 -dichloroflavan. however, despite showing strong in vitro activity, this compound proved unsuccessful in clinical trials [11] . synergism has been demonstrated between various combinations of flavones and flavonols. for example, kaempferol and luteolin show synergy against hsv. it has been suggested that this is why propolis is more active than its individual component compounds [52] . synergism has also been reported between flavonoids and other antiviral agents. quercetin, for example, potentiates the effects of 5-ethyl-2 -dioxyuridine [11] and acyclovir [53] against hsv and pseudorabies infection. apigenin also enhances the antiviral activity of acyclovir against these viruses [53] . the antibacterial activity of flavonoids is being increasingly documented. crude extracts from plants with a history of use in folk medicine have been screened in vitro for antibacterial activity by many research groups. flavonoidrich plant extracts from species of hypericum [54] , capsella [55] and chromolaena [55] have been reported to possess antibacterial activity. many other phytochemical preparations with high flavonoid content have also been reported to exhibit antibacterial activity [22, [56] [57] [58] [59] [60] [61] [62] [63] . propolis has been analysed on many occasions too, and samples containing high concentrations of flavonoids are frequently reported to show antibacterial activity [12, [25] [26] [27] 50, 64] . many research groups have gone one step further and either isolated and identified the structure of flavonoids that possess antibacterial activity, or quantified the activity of commercially available flavonoids. examples of such flavonoids are apigenin [65] [66] [67] [68] [69] [70] [71] [72] [73] , galangin [35, [74] [75] [76] [77] , pinocembrin [78, 79] , ponciretin [80, 81] , genkwanin [66, 82] , sophoraflavanone g and its derivatives [29, [83] [84] [85] , naringin and naringenin [29, 60, 86, 87] , epigallocatechin gallate and its derivatives [74, [88] [89] [90] [91] [92] [93] [94] [95] , luteolin and luteolin 7glucoside [69, 73, 96] , quercetin, 3-o-methylquercetin and various quercetin glycosides [60, 65, 72, 87, [97] [98] [99] [100] [101] [102] and kaempferol and its derivatives [60, 65, 74, 76, 87, 98, 100, 103] . other flavones [32, 60, 74, [104] [105] [106] [107] , flavone glycosides [86, 108, 109] , isoflavones [110, 111] , flavanones [29, 30, 78, 79, 104, [111] [112] [113] [114] , isoflavanones [115] , isoflavans [116] , flavonols [74, 114, 117] , flavonol glycosides [86, [118] [119] [120] and chalcones [79, 104, 111, 121] with antibacterial activity have also been identified. some researchers have reported synergy between naturally occurring flavonoids and other antibacterial agents against resistant strains of bacteria. examples of these include epicatechin gallate [122] [123] [124] [125] and sophoraflavanone g [83, 84] . at least one group has demonstrated synergy between flavonoids with antibacterial activity [126] . others have synthetically modified natural flavones and analysed them for antibacterial activity [94, [127] [128] [129] [130] [131] . for example, wang and colleagues have complexed 5-hydroxy-7,4 -dimethoxyflavone with a number of transition metals and shown that this process increases antibacterial activity [130] . another group reported increased antibacterial activity of 3-methyleneflavanones when the b ring contained bromine or chlorine substituents [131] . two research groups have described the use of flavonoids in vivo. in a study by vijaya and ananthan, oral administration of either 142.9 mg/kg quercetin or 214.3 mg/kg quercetrin protected guinea pigs against an induced shigella infection that killed untreated control animals [132] . more recently, dastidar and co-workers reported that intraperitoneal injection of either 1.58 mg/kg sophoraisoflavone a or 3.16 mg/kg 6,8diprenylgenistein gave significant protection to mice challenged with ∼9.5 × 10 8 colony-forming units (cfus) of salmonella typhimurium [110] . when reports of the antibacterial activity of flavonoids are compared, the results appear widely conflicting (table 2) . for example, it was published that apigenin had no activity against s. aureus at concentrations up to 128 g/ml [72] ; a separate study in the same year reported that the flavone inhibited the growth of 15 strains of mrsa and 5 sensitive strains of s. aureus at concentrations between 3.9 g/ml table 2 the inhibitory activity of apigenin against numerous species of gram-positive and + + dd, disk diffusion assay; bmad, broth macrodilution assay; bmid, broth microdilution assay; ns, assay type not stated in report; awd, agar well diffusion assay; ad, agar dilution assay; +, antibacterial activity detected; −, no antibacterial activity detected. and 15.6 g/ml [73] . from table 2 it can be seen that such discrepancies could perhaps be attributed on occasion to different assays being used (e.g. [65, 70] and [72, 73] ). many different assays are employed in flavonoid research, including the agar dilution technique [29] , the paper disk diffusion assay [115] , the hole-plate diffusion method [22] , the cylinder diffusion method [60] , the broth macrodilution technique [71] and the broth microdilution technique [134] . in particular, assays relying on diffusion of test flavonoids may not give a reliable quantitative measure of antibacterial activity because a potent antibacterial flavonoid may have a low rate of diffusion [32] . however, it is clear from table 2 that additional factors are involved in causing these discrepancies because even groups using the same assay are obtaining conflicting results (e.g. [67, 96] and [67, 72] ). such inconsistencies may be due to variations within each assay. for example, different groups using the agar dilution technique have used different sizes of bacterial inoculum [81, 86] . in a report by the national committee for clinical laboratory standards (nccls), inoculum size was considered the single most important variable in susceptibility testing [135] . it should be noted that many groups assaying flavonoid antibacterial activity have not quantified the test bacterial suspension [60, 115] and others have not even standardised the size of their unenumerated inocula [35, 56, 76, 90, 97] . from the published work it is clear that, in addition to inoculum size, there are many other variable factors for each type of assay. these include volume of broth or agar [90, 116] , type of broth or agar [86, 92] , size of wells [56, 60] , size of paper disks [57, 65] , strains of a particular bacterial species used [69, 72] and incubation period [90, 116] . recently, a set of guidelines was published for standard agar dilution, broth macrodilution and broth microdilution methods [136] . this may help to reduce the number of conflicting reports of flavonoid antibacterial activity in the future. however, it will remain necessary to consider carefully additional variables such as the solvent used to dissolve test flavonoids [116, 118] . it has previously been shown that precipitation occurs when selected flavonoids are dissolved in organic solvents and diluted with neutral polar solutions [75] . precipitation of flavonoids in a minimum inhibitory concentration (mic) assay is likely to cause diminished contact between bacterial cells and flavonoid molecules and may lead to false negative reports of antibacterial activity. also, in improperly controlled experiments, flavonoid precipitation could be misinterpreted as bacterial growth and further false negative results may be recorded as a consequence. the structural alteration of flavonoids such as galangin in alkaline solvents is another matter for consideration [75] . if flavonoid salts are formed and these have increased or decreased potency compared with the parent structure, this may lead to false positive/negative reports of antibacterial activity. other variables worth noting include whether the test flavonoids are obtained from a commercial or natural source [35, 74] and which companies [74, 75] /natural products [71, 72] the compounds are from. the diverse range of cell functions affected by flavonoids in eukaryotic systems is well documented [10, 20] . although there have been comparatively few studies into the mechanisms underlying flavonoid antibacterial activity, information from published literature indicates that different compounds within this class of phytochemicals may target different components and functions of the bacterial cell [137] [138] [139] . if this is the case, it is surprising that the small number of groups which have investigated the relationship between flavonoid structure and antibacterial activity (summarised below) have been able to identify common structural features among active compounds. however, it may be that individual antibacterial flavonoids have multiple cellular targets, rather than one specific site of action. alternatively, these common structural features may simply be necessary for flavonoids to gain proximity to or uptake into the bacterial cell. tsuchiya and colleagues sought to establish a structureactivity relationship for flavanones by isolating a number of differently substituted compounds and determining their mics against mrsa [29] . their study indicated that 2 ,4 -or 2 ,6 -dihydroxylation of the b ring and 5,7-dihydroxylation of the a ring in the flavanone structure was important for anti-mrsa activity. substitution at the 6 or 8 position with a long chain aliphatic group such as lavandulyl (5-methyl-2isopropenyl-hex-4-enyl) or geranyl (trans-3,7-dimethyl-2,6octadienyl) also enhanced activity [29] . interestingly, a recent report by stapleton and colleagues demonstrated that substitution with c 8 and c 10 chains also enhanced the antistaphylococcal activity of flavonoids belonging to the flavan-3-ol class [94] . osawa et al. assessed the activity of a number of structurally different flavonoids including flavones, flavanones, isoflavones and isoflavanones based on the paper disk agar diffusion assay [115] . it was shown that 5-hydroxyflavanones and 5-hydroxyisoflavanones with one, two or three additional hydroxyl groups at the 7, 2 and 4 positions inhibited the growth of streptococcus mutans and streptococcus sobrinus. these results correlate well with those of tsuchiya and colleagues [29] . it was also reported by osawa and colleagues that 5-hydroxyflavones and 5-hydroxyisoflavones with additional hydroxyl groups at the 7 and 4 positions did not exhibit this inhibitory activity [115] . however, when sato et al. examined two isoflavones with hydroxyl groups at the 5, 2 and 4 positions using an agar dilution assay, intensive inhibitory activity was detected against a wide range of streptococcal species [107] . this may suggest that hydroxylation at position 2 is important for activity. alternatively, the lack of activity detected by osawa et al. may simply be due to the poor diffusion of flavones and isoflavones (compared with flavanones and isoflavanones) through the medium. a more recent paper [104] also reports the importance of a hydroxyl group at position 5 of flavanones and flavones for activity against mrsa, supporting the earlier findings of tsuchiya et al. [29] . it further states that chalcones are more effective against mrsa than flavanones or flavones, and that hydroxyl groups at the 2 position are important for the antistaphylococcal activity of these compounds. methoxy groups were reported to drastically decrease the antibacterial activity of flavonoids [104] . the importance of hydroxylation at the 2 position for antibacterial activity of chalcones is supported by earlier work from sato and colleagues, who found that 2,4,2 -trihydroxy-5 -methylchalcone and 2,4,2trihydroxychalcone inhibited the growth of 15 strains of cariogenic streptococci [140] . as mentioned previously, ward and colleagues synthesised a number of halogenated derivatives of 3methyleneflavanone [131] . substitution of the b ring was found to enhance antibacterial activity, with 3 -chloro, 4chloro and 4 -bromo analogues each being approximately twice as effective as their parent compound against s. aureus, and four times more active against enterococcus faecalis. also, the 2 ,4 -dichloro derivative exhibited a four-to eightfold improvement in activity against s. aureus and a twoto four-fold improvement against e. faecalis. by contrast, 3-methylene-6-bromoflavanone was less potent than the parent compound and the authors suggested that halogenation of the a ring may diminish activity [131] . clearly, however, it would be necessary to prepare analogues with substitution at other a-ring positions before this could be said with any certainty. in chalcones, neither fluorination nor chlorination at position 4 of the b ring is reported to affect antibacterial potency significantly [104] . again, however, other structural analogues of this class of flavonoids would need to be synthesised and examined before the effect of halogenation upon antibacterial activity could be properly assessed. several research groups have attempted to determine whether flavonoid activity is bacteriostatic or bactericidal by conducting time-kill studies. in such experiments, epigallocatechin gallate [89] , galangin [75] and 3-o-octanoyl-(+)-catechin [94] have been shown to cause a reduction of 1000-fold or more in viable counts of mrsa-yk, s. aureus nctc 6571 and emrsa-16, respectively. this would immediately appear to suggest that flavonoids are capable of bactericidal activity. however, it has recently been demonstrated that 3-o-octanoyl-(−)-epicatechin induces the formation of pseudomulticellular aggregates both in antibiotic-sensitive and antibiotic-resistant strains of s. aureus [94] . if this phenomenon is induced by other compounds within the flavonoid class (and liposomal studies suggest that this is the case for epigallocatechin gallate [88] ), questions are raised regarding the interpretation of results from time-kill studies. it may be that flavonoids are not killing bacterial cells but merely inducing the formation of bacterial aggregates and thereby reducing the number of cfus in viable counts. in a study using radioactive precursors, mori and colleagues showed that dna synthesis was strongly inhibited by flavonoids in proteus vulgaris, whilst rna synthesis was most affected in s. aureus [138] . flavonoids exhibiting this activity were robinetin, myricetin and (−)-epigallocatechin. protein and lipid synthesis were also affected but to a lesser extent. the authors suggested that the b ring of the flavonoids may play a role in intercalation or hydrogen bonding with the stacking of nucleic acid bases and that this may explain the inhibitory action on dna and rna synthesis [138] . ohemeng et al. screened 14 flavonoids of varying structure for inhibitory activity against escherichia coli dna gyrase, and for antibacterial activity against staphylococcus epidermidis, s. aureus, e. coli, s. typhimurium and stenotrophomonas maltophilia [68] . it was found that e. coli dna gyrase was inhibited to different extents by seven of the compounds, including quercetin, apigenin and 3,6,7,3 ,4pentahydroxyflavone. interestingly, with the exception of 7,8-dihydroxyflavone, enzyme inhibition was limited to those compounds with b-ring hydroxylation [68, 141] . the authors proposed that the observed antibacterial activity of the seven flavonoids was due in part to their inhibition of dna gyrase. however, since the level of antibacterial activity and enzyme inhibition did not always correlate, they also suggested that other mechanisms were involved [68] . more recently, plaper and colleagues reported that quercetin binds to the gyrb subunit of e. coli dna gyrase and inhibits the enzyme's atpase activity [142] . enzyme binding was demonstrated by isolating e. coli dna gyrase and measuring quercetin fluorescence in the presence and absence of the gyrase subunits. the flavonoid-binding site was postulated to overlap with those of atp and novobiocin, since addition of these compounds interfered with quercetin fluorescence. inhibition of gyrb atpase activity by quercetin was also demonstrated in a coupled atpase assay. this research is in agreement with the earlier findings of ohemeng et al. [68] and supports the suggestion that quercetin's antibacterial activity against e. coli may be at least partially attributable to inhibition of dna gyrase. when screening natural products for type ii topoisomerase inhibitors, bernard and co-workers found that the glycosylated flavonol rutin was very effective [143] . this compound exhibited antibacterial activity against a permeable e. coli strain (a strain into which the enva1 allele had been incorporated [144, 145] ). using enzyme assays and a technique known as the sos chromotest, it was shown that rutin selectively promoted e. coli topoisomerase iv-dependent dna cleavage, inhibited topoisomerase iv-dependent decatenation activity and induced the sos response of the e. coli strain. the group suggested that since topoisomerase iv is essential for cell survival, the rutin-induced topoisomerase iv-mediated dna cleavage leads to an sos response and growth inhibition of e. coli cells [143] . within our own laboratory, a 4-quinolone-resistant s. aureus strain was shown to have increased susceptibility to the flavonol galangin compared with other 4-quinolonesensitive and -resistant strains [146] . interestingly, this strain possesses a distinct amino acid substitution (serine to proline) at position 410 of the grlb subunit. this may suggest that topoisomerase iv and the relatively homologous gyrase enzyme are involved in the antibacterial mechanism of action of galangin. clearly, however, further work with mutant strains and purified enzymes would be necessary before this could be verified. a research team that had previously found sophoraflavanone g to have intensive antibacterial activity against mrsa and streptococci [83] [84] [85] recently reported attempts to elucidate the mechanism of action of this flavanone [139] . the effect of sophoraflavanone g on membrane fluidity was studied using liposomal model membranes and compared with the less active flavanone naringenin, which lacks 8-lavandulyl and 2 -hydroxyl groups. at concentrations corresponding to the mic values, sophoraflavanone g was shown to increase fluorescence polarisation of the liposomes significantly. these increases indicated an alteration of membrane fluidity in hydrophilic and hydrophobic regions, suggesting that sophoraflavanone g reduced the fluidity of outer and inner layers of membranes. naringenin also exhibited a membrane effect but at much higher concentrations. this correlation between antibacterial activity and membrane interference was suggested to support the theory that sophoraflavanone g demonstrates antibacterial activity by reducing membrane fluidity of bacterial cells [139] . another group, ikigai and colleagues, carried out research on (−)-epigallocatechin gallate, a strongly antibacterial catechin found in green tea. catechins are a group of flavonoids that appear to have greater activity against gram-positive than gram-negative bacteria [88] . in this study, liposomes were again used as model bacterial membranes, and it was shown that epigallocatechin gallate induced leakage of small molecules from the intraliposomal space. aggregation was also noted in liposomes treated with the compound. the group therefore concluded that catechins primarily act on and damage bacterial membranes. it was not known how this damage occurred but two theories were put forward. first, catechins may perturb the lipid bilayers by directly penetrating them and disrupting the barrier function. alternatively, catechins may cause membrane fusion, a process that results in leakage of intramembranous materials and aggregation. interestingly, the group also demonstrated that leakage induced by epigallocatechin gallate was significantly lower when liposome membranes were prepared containing negatively charged lipids. it was therefore suggested that the low catechin susceptibility of gram-negative bacteria may be at least partially attributable to the presence of lipopolysaccharide acting as a barrier [88] . as mentioned previously, stapleton and colleagues found that substitution with c 8 and c 10 chains increased the antibacterial activity of selected flavan-3-ols (catechins). the group went on to show that cells of an mrsa clinical isolate treated with (−)-epicatechin gallate and 3-o-octanoyl-(+)-catechin, respectively, exhibited moderately and highly increased levels of labelling with the selectively permeable fluorescent stain propidium iodide. in addition, when s. aureus cells were grown in the presence of either (−)-epicatechin gallate or 3-o-octanoyl-(−)-epicatechin and examined by transmission electron microscopy, they were shown to form pseudomulticellular aggregates [94] . this work constitutes a substantial advance in the development of catechins as antibacterial agents and lends support to ikigai's argument that catechins act on and damage bacterial membranes. it has also been demonstrated by sato and colleagues that the chalcone 2,4,2 -trihydroxy-5 -methylchalcone induces leakage of 260 nm absorbing substances from s. mutans. this observation generally indicates leakage of intracellular material such as nucleotide, and the authors suggested that 2,4,2 -trihydroxy-5 -methylchalcone exerts its antibacterial effect by changing the permeability of the cellular membrane and damaging membrane function [140] . in addition, the effect of galangin upon cytoplasmic integrity in s. aureus has been investigated by measuring loss of internal potassium [147] . when high cell densities of s. aureus were incubated for 12 h in media containing 50 g/ml of the flavonol, a 60-fold decrease in the number of cfus was noted and cells lost ca. 20% more potassium than untreated control bacteria. these data strongly suggest that galangin induces cytoplasmic membrane damage and potassium leakage. whether galangin damages the membrane directly, or indirectly as a result of autolysis or cell wall damage and osmotic lysis, remains to be established however [147] . in an investigation into the antimicrobial action of propolis, mirzoeva and colleagues showed that one of its constituent flavonoids, quercetin, caused an increase in permeability of the inner bacterial membrane and a dissipation of the membrane potential [148] . the electrochemical gradient of protons across the membrane is essential for bacteria to maintain capacity for atp synthesis, membrane transport and motility. mirzoeva et al. suggested that the effect of propolis on membrane permeability and membrane potential may contribute enormously to its overall antibacterial activity and may decrease the resistance of cells to other antibacterial agents. it was thought that this might explain the synergistic effect that occurs between propolis and other antibiotics such as tetracycline [148] and ampicillin [149] . the group also demonstrated that the flavonoids quercetin and naringenin significantly inhibited bacterial motility, providing further evidence that the proton motive force is disrupted. bacterial motility and chemotaxis are thought to be important in virulence as they guide bacteria to their sites of adherence and invasion. mirzoeva et al. suggested that the antimotility action of propolis components may have an important role in inhibition of bacterial pathogenesis and the development of infection [148] . the cytoplasmic membrane activity detected for quercetin by mirzoeva and co-workers may represent one of the additional mechanisms of antibacterial action that was suspected to be present among the seven dna gyrase-inhibiting flavonoid compounds tested by ohemeng and colleagues [68] . haraguchi and colleagues recently carried out an investigation into the antibacterial mode of action of two retrochalcones (licochalcone a and c) from the roots of glycyrrhiza inflata [137] . these flavonoids demonstrated inhibitory activity against s. aureus and micrococcus luteus but not against e. coli, and in preliminary tests licochalcone a inhibited incorporation of radioactive precursors into macromolecules (dna, rna and protein). the group hypothesised that the licochalcones may be interfering with energy metabolism in a similar way to respiratory-inhibiting antibiotics, since energy is required for active uptake of various metabolites and for biosynthesis of macromolecules [137] . interestingly, the licochalcones were found to inhibit strongly oxygen consumption in m. luteus and s. aureus but not in e. coli, which correlated well with the observed spectrum of antibacterial activity. the group further demonstrated that licochalcones a and c effectively inhibited nadh-cytochrome c reductase, but not cytochrome c oxidase or nadh-coq reductase. it was therefore suggested that the inhibition site of these retrochalcones was between coq and cytochrome c in the bacterial respiratory electron transport chain [137] . merck research laboratories recently reported that the flavanone lonchocarpol a inhibits macromolecular synthesis in bacillus megaterium. using radioactive precursors, it was demonstrated that rna, dna, cell wall and protein synthesis were all inhibited at concentrations similar to the mic value [150] . this may represent another example of a flavonoid that interferes with energy metabolism. with regard to natural products, it is generally accepted that phytochemicals are less potent anti-infectives than agents of microbial origin, i.e. antibiotics [48] . however, new classes of antimicrobial drug are urgently required and the flavonoids represent a novel set of leads. future optimisation of these compounds through structural alteration may allow the development of a pharmacologically acceptable antimicrobial agent or group of agents. existing structure-activity data suggest that it might be possible, for example, to prepare a potent antibacterial flavanone by synthesising a compound with halogenation of the b ring as well as lavandulyl or geranyl substitution of the a ring. also, it is worth noting that the rapid progress which is being made toward elucidation of flavonoid biosynthetic pathways [151] may soon allow the production of structural analogues of active flavonoids through genetic manipulation. screening of these analogues might lead to the identification of compounds that are sufficiently potent to be useful as antifungal, antiviral or antibacterial chemotherapeutics. in addition to the structural alteration of weak and moderately active antimicrobial flavonoids, investigation into the mechanisms of action of these compounds is likely to be a productive area of research. such information may assist in the optimisation of a lead compound's activity, provide a focus for toxicological attention and aid in the anticipation of resistance. also, characterisation of the interaction between antimicrobial flavonoids and their target sites could potentially allow the design of secondgeneration inhibitors. infectious diseases society of america. statement of the idsa concerning 'bioshield ii: 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in staphylococcus aureus by catechins and gallates rutin-enhanced antibacterial activities of flavonoids against bacillus cereus and salmonella enteritidis synthesis and antimicrobial activity of flavone-6-carboxaldehyde oxime ether derivatives synthesis and antimicrobial activity of flavone-3 -carboxaldehyde oxime ether derivatives synthesis and antimicrobial activity of some new flavonyl oxime ether derivatives synthesis, characterization, and antibacterial activity of transition metal complexes with 5-hydroxy-7,4 -dimethoxyflavone antimicrobial 3-methyleneflavanones therapeutic efficacy of medicinal plants against experimentally induced shigellosis in guinea pigs isolation of the antimicrobial alkaloid stemmadenine from iraqi rhazya stricta baicalin synergy with beta-lactam antibiotics against methicillin-resistant staphylococcus aureus and other beta-lactam-resistant strains of s. aureus methods for determining bactericidal activity of antimicrobial agents methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically mode of antibacterial action of retrochalcones from glycyrrhiza inflata antibacterial activity and mode of action of plant flavonoids against proteus vulgaris and staphylococcus aureus reduction of membrane fluidity by antibacterial sophoraflavanone g isolated from sophora exigua growth inhibition of oral bacteria related to denture stomatitis by anticandidal chalcones a comparison of active site binding of 4-quinolones and novel flavone gyrase inhibitors to dna gyrase characterization of quercetin binding site on dna gyrase glycosylated flavones as selective inhibitors of topoisomerase iv transduction and dominance studies of the enva gene present in a chain-forming mutant of escherichia coli k12 mutant of escherichia coli with anomalous cell division and ability to decrease episomally and chromosomally mediated resistance to ampicillin and several other antibiotics assessment of the antibacterial activity of galangin against 4-quinolone resistant strains of staphylococcus aureus detection of galangin-induced cytoplasmic membrane damage in staphylococcus aureus by measuring potassium loss antimicrobial action of propolis and some of its components: the effects on growth, membrane potential and motility of bacteria svabic-vlahovic m. in vitro antimicrobial activity of propolis and synergism between propolis and antimicrobial drugs antibacterial activity of lonchocarpol a prospects for the metabolic engineering of bioactive flavonoids and related phenylpropanoid compounds the authors are very grateful to dr paul kong and dr satyajit sarker for critiquing preliminary drafts of the manuscript and for advice on flavonoid classification and structure. thanks are extended to dr peter taylor for insightful comments regarding interpretation of data from time-kill studies with flavonoids. thanks also to dr derek chapman, miss vivienne hamilton, dr bruce thomson and mrs amina al-mossawi for their kind support and encouragement. key: cord-270424-8yhsjbmi authors: kang, dongwei; zhang, heng; zhou, zhongxia; huang, boshi; naesens, lieve; zhan, peng; liu, xinyong title: first discovery of novel 3-hydroxy-quinazoline-2,4(1h,3h)-diones as specific anti-vaccinia and adenovirus agents via ‘privileged scaffold’ refining approach date: 2016-11-01 journal: bioorg med chem lett doi: 10.1016/j.bmcl.2016.09.071 sha: doc_id: 270424 cord_uid: 8yhsjbmi a series of 1,2,3-triazolyl 3-hydroxy-quinazoline-2,4(1h,3h)-diones was constructed utilizing cu(i)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (cuaac) method. the biological significance of the novel synthesized quinazolines was highlighted by evaluating them in vitro for antiviral activity, wherein several compounds exhibited excellent activity specifically against vaccinia and adenovirus. especially, 24b11 displayed the most potent inhibitory activity against vaccinia with an ec(50) value of 1.7 μm, which was 15 fold than that of the reference drug cidofovir (ec(50) = 25 μm). 24b13 was the most potent compound against adenovirus-2 with an ec(50) value of 6.2 μm, which proved lower than all the reference drugs. preliminary structure–activity relationships were also discussed. to the best of our knowledge, no data are present in the literature on antiviral activity of 3-hydroxy-quinazoline-2,4(1h,3h)-diones against dna-viruses. thus, these findings warrant further investigations (library expansion and compound refinement) on this novel class of antiviral agents. poxvirus-associated diseases are a major threat for human health. 1 smallpox, a highly transmissible and infectious disease with high morbidity and mortality, was the most dangerous human pathogen of poxviruses group. 2 although smallpox was declared eradicated in 1980 by the world health organization (who) after an intensive immunization campaign with the vaccinia virus vaccine of the global, there are stocks of varv were kept in two who-approved laboratories: the u.s. center for disease control and prevention (cdc) in atlanta and the russian state research center of virology and biotechnology in novosibirsk. 3, 4 by the fact that the vaccinia virus vaccines have substantial side effects, 5 the vaccination programs have been terminated since the last century, which led to the human population today more susceptible to a smallpox disaster. in addition, the emergence of zoonotic poxvirus infections such as the monkeypox virus in both the us and western africa in human populations aggravated the people's panic. 6 for all of these reasons, special attention has been paid to establish efficient safe therapies for dealing with poxvirus infections. in spite of number of potential antipoxviral agents have been reported recently, there have no approved drugs by us food and drug administration (fda) for the prevention and treatment of smallpox infections available on the market currently. cidofovir (cdv, 1) is a potent and selective anti-dna virus agent and can inhibit viral dna replication (fig. 1) , so it has a broad-spectrum activities and has been approved for the treatment of smallpox virus. but the low oral bioavailability of cdv and potential nephrotoxicity accompany with its intravenous administration limited the clinical application of the cdv. recently, the lipophilic prodrug of cdv, hexadecyloxypropyl ester (hdp-cdv, 2), was demonstrated that have improved bioavailability and equivalent effectiveness against orthopoxvirus infections and is in phase i/ii clinical studies currently. 7 moreover, tecovirimat (st-246, 3), an orally bioavailable compound that targets the f13l protein of the virus, which inhibit the growth of multiple orthopoxviruses and has significant antiviral activity in various poxvirus disease animal models, was demonstrated favorable safety, tolerability, and pharmacokinetics in phase i clinic trial. 8, 9 in 2010, tecovirimat was received both orphan drug designation and fast-track status from the us fda and with the hope that it can be approved for the prevention and treatment of smallpox infections. adenoviruses (advs) are double-stranded dna viruses (about 60-100 nm in size) with a nonenveloped icosahedral capsid and a genome of 26-45 kb. 9 advs comprise more than 50 human ad serotypes, which have been identified and classified into six species (a-f) in terms of their biological, physiochemical and genetic properties. 10 advs are opportunistic pathogens and associated with a wide variety of severe clinical symptoms in healthy individuals, such as respiratory illness, renal disease, gastroenteritis, hemorrhagic cystitis, and so on. 11-13 however, they are generally not considered to be highly pathogenic viruses for the reason that the adenovirus infections are most often self-limited in immunocompetent individuals. but an adenovirus infection might led to severe and life-threatening disease (multiple organ failure) in the immunocompromised individuals. 14 during the last two decades, a number of adenovirus serotypes that largely from species a, b, and c were isolated from immunocompromised patients successfully. ad2, a species a serotype that has been most detailed studied of adenovirus so far, are often associated with respiratory illness with a lethal outcome occasionally. currently, there have no available drugs for treatment of advs infections. cidofovir was proved to be the most promising anti-adenoviral agent of those currently used in clinical settings, but the outcome in the hematopoietic stem cell recipients has been found to be poor adenovirus infections. 15 therefore, there is compelling need for the discovery of new antiviral drugs of vaccinia and adenovirus that possess an improved safety property and oral bioavailability. over the past few decades, serendipitous or high-throughput screen (hts) campaign of heterocyclic compound collections continues to remain a major paradigm for antiviral hits or leads discovery. 16, 17 due to their chemical and biological importance, hydroxy-(iso)quinazoline-2,4(1,3)-dione and its analogues are attractive 'privileged structures' in antiviral medicinal chemistry. recently, 2-hydroxyisoquinoline-1,3(2h,4h)-dione and 3-hydroxypyrimidine-2,4-dione derivatives were reported as miscellaneous inhibitors targeting bridged dinuclear metalloenzymes, such as hiv rnase h and integrase (in) dual inhibitors 4-7 18 , 8, 9 19 , 10 20 , hiv rnase h active-site inhibitors mb-76 (11) 21-23 and 12 24 , as well as hepatitis c virus (hcv) ns5b polymerase inhibitor 13 25 (fig. 2) , suggesting that these divalent metal ion chelators could be useful inhibitor scaffolds with a broad range of biological activity via various modifications. 26 evolved from the concept of drug repositioning, 'privileged structure'-guided scaffold refining is a very effective strategy to exploit undescribed bioactivites by making full use of readily derivatized scaffolds with well-established synthetic methods. 27 in this context, in view of the above fact and to discover completely new anti-vaccinia and adenovirus agents with a novel skeleton and unique mode of action, a relatively small library of 6-(1-benzyl-1h-1,2,3-triazol-4-yl)-3-hydroxyquinazoline-2,4(1h,3h)-dione compounds (the general formula in scheme 1) was constructed via the copper(i)-catalyzed azidealkyne cycloaddition (cuaac) reaction 28 and the biological significance of the novel synthesized quinazolines was highlighted by evaluating them in cell culturebased antiviral high-throughput screening (hts) assays against a broad panel of dna viruses, retroviruses and several rna viruses. the library of 3-hydroxyquinolin-2(1h)-one compounds was constructed by the following general synthetic route, which was straightforward and depicted in scheme 1. the starting material 2-hydroxyisoindoline-1,3-dione (14) was firstly reacted with benzyl bromide to obtain 2-(benzyloxy)isoindoline-1,3-dione (15) . then 15 was treated with hydrochloric acid and acetic acid via an acidulation reaction to form the key intermediate o-benzylhydroxylamine hydrochloride (16) . 29 meanwhile, the commercially available material 2-amino-5-iodobenzoic acid (17) (19) was obtained by ring closure of 18 with carbonyldimidazole (cdi) and 16 under the condition of sodium hydroxide. 30, 31 then this heterocyclic scaffold was alkylated with iodomethane and iodoethane in dmf afforded the n 1methylation product 20a and n 1 -ethylation product 20b respectively. the key alkyne building block 22a or 22b was prepared from 20a or 20b via the sonogashira cross-coupling reaction and trimethylsilyl-removal reaction successfully. copper(i) catalyzed click reaction (cuaac) of the alkyne key intermediate 22a or 22b with different azido substituent groups generated the corresponding key 1,2,3-triazole intermediates (23a01-23a13 and 23b01-23b13), which were deprotected under basic condition affording two series of target compounds 1,2,3-triazole-substituted 3hydroxy-quinazoline-2,4(1h,3h)-diones 24a01-24a13 and 24b01-24b13. their structures were determined by their 1 h nmr, 13 c nmr, and ms (esi) spectra. notably, the 1 h nmr spectrum showed a singlet at 8.50 corresponding to the triazolyl proton while the 13 c nmr spectrum showed peaks at 125.73-125.90 and 149.12-149.65 corresponding to ch and qc characteristic to the triazole core unit. the newly synthesized 1,2,3-triazole-linked 3-hydroxy-quinazoline-2,4 (1h,3h)-diones were performed to evaluate against their antiviral activity against a broad panel of dna virus, including herpes simplex virus-1 (kos), herpes simplex virus-2 (g), herpes simplex virus-1 tkkos acvr, vaccinia virus and adeno virus-2 (evaluated in infected human embryonic lung fibroblast (hel) cells). in addition, all the compounds were also examined against retroviruses [i.e., human immunodeficiency virus type 1 (hiv-1) and type 2 (hiv-2)] and several rna viruses [i.e., human coronavirus and influenza virus]. the results were expressed as ec 50 and mcc (minimum cytotoxic concentration) ( table 1) . as shown in table 1 hdp-cdv (2) on vaccinia and adenovirus and this study can help to relate the structural characteristics of this complexes to their antiviral activity. preliminary investigation of the structure-activity relationships (sars) revealed that the nature of the n 1 -r substituent and the aryl group which connected to the triazole influenced the antiviral activity remarkably. for instance, the result revealed that the antiviral activity of n 1 -ethyl substituted analogues are more potent than that of the corresponding n 1 -methyl substituted counterparts (ec 50 : 24b07 > 24a07, 24b11 > 24a11 and 24b13 > 24a13). especially, most of n 1 -ethyl substituted analogues showed favorable activity against adenovirus, but nearly all the compounds lost their activity when the compounds with n 1 -methyl substituted counterparts with an exception of compound 24a12. introduction of an electron-withdrawing group at the para substituents of the aryl can remarkable improve the anti-vaccinia activities (no 2 > -cn > f > ch 3 ). to the contrary, a strong electron-withdrawing group can result in the compound lost their adenovirus activities, but the compounds with electrondrawing group (24b13 and 24a13) exhibited the most potent antiviral activity against adenovirus. when comparing compound 24b01 with 24b02, 24b03, 24b06, 24b07 and 24b08, only compound with fluorine substituted in the meta and para position of the aryl simultaneous can display potent inhibitory activity toward vaccinia (24b07, ec 50 = 1.9 lm). but for the adenovirus, compounds with ortho or meta substituted showed moderate inhibitory activity (24b01, ec 50 = 6.5 lm; 24b03, ec 50 = 13 lm), and para-substituted counterpart was inactive (24b02, ec 50 > 100 lm); moreover, changing the pattern of substitution on the aryl to disubstituted resulted in reduced activity (24b06, ec 50 = 8 lm), even completely lost inhibitory activity (24b08 and 24b09, ec 50 > 100 lm). in conclusion, a series of novel 1,2,3-triazole-containing 3hydroxy-quinazoline-2,4(1h,3h)-diones has been synthesized using cuaac reaction, and was firstly identified as potent and specific vaccinia and adenovirus inhibitors in vitro. among them, 24b11 and 24b13 was demonstrated with the most potent vaccinia and adenovirus inhibitory activity respectively, which were promising compounds for further exploration as drug candidates for anti-poxvirus or adenovirus therapy. preliminary sars were discussed with the hope to provide a helpful guidance for the design of next-generation of quinolinone analogues. obviously, the mechanism of action and precise viral target of these 1,2,3-triazolyl 3-hydroxy-quinazoline-2,4(1h,3h)-diones derivatives presented here remain to be identified. consequently, a detailed study on further elaboration of these 3-hydroxy-quinazoline-2,4 (1h,3h)-diones and investigation of their prospective mechanism of action is currently underway in our lab and would be disclosed in due course. the financial support from the national natural science molecular epidemiology of human adenoviruses key: cord-265764-h4zg0q8x authors: singh, kamaljit; kaur, hardeep; chibale, kelly; balzarini, jan title: synthesis of 4-aminoquinoline–pyrimidine hybrids as potent antimalarials and their mode of action studies date: 2013-06-10 journal: eur j med chem doi: 10.1016/j.ejmech.2013.05.046 sha: doc_id: 265764 cord_uid: h4zg0q8x one of the most viable options to tackle the growing resistance to the antimalarial drugs such as artemisinin is to resort to synthetic drugs. the multi-target strategy involving the use of hybrid drugs has shown promise. in line with this, new hybrids of quinoline with pyrimidine have been synthesized and evaluated for their antiplasmodial activity against both cq(s) and cq(r) strains of plasmodium falciparum. these depicted activity in nanomolar range and were found to bind to heme as well as at rich puc18 dna. malaria is one of the most widespread diseases besides tuberculosis and aids which affects more than 500 million people worldwide and results in around 1e3 million causalities every year [1] . in africa alone, around 20% childhood deaths are due to malaria and a child dies every 30 s [2] and it is estimated that an african child has on an average 1.6e5.4 episodes of malaria fever each year. of the four typically recognized plasmodium species causing disease in humans, plasmodium falciparum is most deadly to children below the age of five leading to mortality while plasmodium vivax is most morbidity prone, and is responsible for latent infection that hampers current control and future elimination efforts [3] . the development of drug resistance for the common antimalarials such as 4-/ 8-aminoquinolines, 4-methanol quinolines, antifolate drugs, sesquiterpene lactones etc. (fig. 1) is a rather serious issue which has stimulated considerable research efforts in the development of new drugs using different approaches [4, 5] of which the molecular hybridization approach [6, 7] is quite an attractive strategy which involves design of new chemical entities by covalent fusion of two drugs, both active compounds and/or pharmacophoric units derived from known bioactive molecules with complimentary activities and multiple pharmacological targets. the multiple target strategy led to the design of hybrid of 4-aminoquinoline with species such as triazine [8, 9] , ferrocene [10] , rhodanine [11] , thiazolidine-4-one [12] , chalcone [13] , trioxane [14] , isatin [15] and recently, pyrimidines [16e18] (fig. 2) . quinoline containing drugs (chloroquine and primaquine, fig. 1 ) are known to affect parasite metabolism and cause parasite death by blocking the polymerization of the toxic heme, into an insoluble and non-toxic pigment, hemozoin, resulting in cell lysis and parasite cell auto digestion [19e21] . on the other hand, pyrimidine-based compounds are well known for their wide range of promising antiviral [22] , antitubercular [23] , anti-aids [24] , antinociceptive [25] , antifungal [26] , antitumor [27] and antimalarial activities [28] apart from their role in the nucleic acid synthesis. thus, linking of the quinoline unit with pyrimidine might furnish conjugate hybrids that are capable of showing useful antimalarial activity. recently, antimalarial activities of some quinolineepyrimidine hybrids with activities in the micromolar to nanomolar range have been reported (fig. 3) [16e18 ,29] . in yet another report on the evaluation of quinolineepyrimidine, the activity (in micromolar range) was also reported for fixed combinations of the chloroquine and pyrimethamine. in all these reports, the pyrimidines were linked to the quinoline unit through 2-, 4-and 6-positions. we have employed rather conformationally flexible pyrimidine-5-carboxylates linked covalently to 4-aminoquinoline core. these novel pyrimidine carboxylate hybrids interact with the iron center of free heme within the physiological environment (ph 5.6), a key step in the accumulation of heme which is selectively toxic to the parasite. to enhance the possibility to accumulate within the digestive vacuole via weak-base trapping (the mechanism by which cq and other quinoline antimalarials attain high concentrations inside this compartment), we developed a novel class of antimalarials using a pharmacophore hybridization approach in which the pyrimidine-5-carboxylate motif was hybridized with an iron-complexing, 4-aminoquinoline moiety through c-2 position [29] . to further elaborate the structureeactivity profile, here, we present additional new 4-aminoquinolineepyrimidine carboxylate hybrids. we also report on their antimalarial activity against both cq sensitive (cq s dd2) as well as cq resistant (cq r d10) strains. finally, the mechanism of action studies with the representative compounds has also been performed. the 4-aminoquinolineepyrimidine-5-carboxylate hybrids were synthesized in economical way using synthetic approach outlined in scheme 1. the key starting compound, 3,4-dihydropyrimidin-2(1h)-one 1 was prepared through nh 4 cl/tfa [30, 31] catalyzed three-component biginelli condensation of an alkyl acetoacetate, urea and appropriate aldehyde or its formyl equivalent: 1,3oxazinane derivative, in acetonitrile or under solvent-free reaction conditions, in some cases. subsequent oxidation of 1 using 60% nitric acid readily furnished pyrimidinones 2 which upon chlorination with pocl 3 yielded 3 [32] . the nucleophilic substitution reaction of 3 with appropriate 4-amino-7-chloroquinoline 4 which in turn was prepared from the commercially available 4,7dichloroquinoline and diaminoalkanes [33] , gave 5aeg in good yields ( table 1) . structures of 1e5 were unambiguously established on the basis of spectral ( 1 h nmr, 13 c nmr, ms, ft ir) as well as microanalytical analysis. we have previously established that the 4-aminoquinolinee pyrimidine hybrids 6aec intercepted by a diaminoalkyl spacer showed optimum potency (table 1) , when the flexible spacer consisted of three or four carbon atoms [29] . further, the introduction of nitro substituent at ortho position of the phenyl ring at the c-4 of the pyrimidine core furnished the most potent compound 6c with antimalarial activity superior to the standard cq and close to artesunate [29] . keeping these observations in mind, we planned to further refine the activity of these persuasive 4aminoquinolineepyrimidine by incorporating electron withdrawing substituents at c-4 phenyl of pyrimidine core, as well as by varying the c-5 ester substituent and also by altering the basicity of diaminoalkyl spacer. the in vitro antimalarial screening of the new synthesized compounds 5aeg revealed good to moderate activities in nm range against both the tested dd2 (cq s ) and d10 strains (cq r ) of p. falciparum (table 1) . although the tested hybrids were not as active as the standard drugs viz. cq and asn, interesting sars have been drawn. analysis of the activity of the compounds recorded in table 1 reveals that replacing c-5 ethyl ester of the previously reported [29] decrease in antimalarial activity against both the chloroquine sensitive and chloroquine resistant strains of p. falciparum. however, comparison of hybrids 5b, 5c with 6b, 6c having an identical butyl spacer showed that incorporation of isopropyl ester at c-5 of pyrimidine motif (5b and 6b) increased the antimalarial activity against the cq s strain whereas considerable decrease in activity was observed for cq r strain of p. falciparum. also, the most potent compound 5b of the series displayed 2-fold increase in antimalarial activity than the standard cq against cq r strain of p. falciparum. when the diaminoalkyl linker of compound 6a was replaced with relatively less basic alkoxy amino linker 5d considerable decrease in antimalarial activity was observed which in turn linked to the decreased accumulation of compound via ph trapping into the digestive vacuole. it was not unexpected since the basicity of alkyl chain linker plays crucial role in determining the antimalarial activity of this class of compounds. furthermore, the introduction of a nitro substituent on the phenyl ring at the c-4 position of the pyrimidine core to create 5c resulted in a significant increase in antiplasmodial activity in comparison to the p-chloro/p-fluoro substituents (5e and 5f). moreover, the hybrid 5g lacking a c-4 substituent on the pyrimidine motif led to an increase in antimalarial activity against both the cq s as well as cq r strains of p. falciparum. however, although the antimalarial activity of 5g was superior to 5c, 5e & 5f, it was less than the corresponding c-4 phenyl substituted analogs 5b as well as 6b. thus, the sar study suggested that both the substitution of the c-4 phenyl group with electron withdrawing groups and alterations in basicity of linker leads to better antimalarial activity. unfortunately, these compounds suffer from high clogp values which are in the range 5e8 (table 1) , which are suggestive of the fact that these possess limited aqueous solubility. however, it is not a serious limitation in view of recent advancements in formulation methods. compounds 5aeg were evaluated for their toxicity against various (hela, vero, crfk, hel and mdck) cell cultures (table 1 & si table s1 ). toxicity data revealed that these compounds exhibit high toxicity (low cc 50 ) against mdck cell cultures while cc 50 values are quiet high for other cell cultures. the cc 50 values for inhibition of mdck cells summarized in table 1 indicate that the strongest antimalarial compound 5b was mildly cytotoxic (table 1) . further, the ratio of the cytotoxicity (cc 50 in mm) and in vitro antimalarial activity (ic 50 in nm for dd2 strain) enabled the determination of selectivity index (si) for these compounds. compound 5d with alkoxy amino linker and compound 5g bearing c-4 unsubstituted pyrimidine motif exhibited high cc 50 values and thus led to fairly safe selectivity index values (table 1) . compound 5d having less basic alkyl spacer, displayed highest si (43.6) whereas the most potent compound 5b exhibit relatively low si value (3.92 table s1 ) and (vii) feline corona virus (fipv) and feline herpes virus activity in crfk cell cultures ( table 2 ). the anti-viral activity of most of the compounds was not impressive except compounds 5a and 5c which exhibited relatively low ec 50 's only against the feline corona virus (fipv) and feline herpes virus in crfk cell cultures ( table 2) . quinoline antimalarials (e.g., cq, amodiaquine and quinine) act principally by forming adducts with ferriprotoporphyrin ix, thus blocking haemozoin formation [38] . in this study, we have evaluated the mechanism of antimalarial activity of the most potent compound 5b of the series by studying its binding with heme (fig. 4) . the titration of monomeric heme was also performed at the plasmodial food vacuole ph 5.6 using mes buffer instead of hepes to ensure that the compound 5b binds with heme even at acidic ph (s1). a 1:1 stoichiometry of the most stable complex of 5b with monomeric heme at ph 7.4 and 5.6 was established from the job's plot (si figure s1 ). the association constants (table 3) were calculated by analyzing the titration curves obtained at ph 7.4 using hypspecea non-linear least square fitting programme [39] . the binding of cq with heme under identical conditions was also determined in the similar manner and the results are presented in table 3 for comparison. table 3 shows that the association constants for the complexes formed between monomeric heme and 5b (log k 4.96) are comparable with those of standard antimalarial drug, cq (log k 5.15). furthermore, the decrease of apparent ph from 7.4 to 5.6 ( table 3) has little effect on the binding constants indicating binding is stronger even at acidic ph. to further establish the binding of 5b with monomeric heme, 1 h nmr titrations were performed and shifts in the peaks as well as peak intensity noted. the addition of 30 mol% of heme dissolved in 40% dmso to a solution of 5b in 40% dmso:d 2 o\d 2 so 4 (10 ml) caused a shift in the aromatic proton signals (fig. 5) , indicating binding of 5b with heme but further addition of heme led to broadening of the peaks. an equimolar (3.9 mmol) solution of hemin chloride and 5b when analyzed in mass spectrometer depicted an intense molecular ion peak at 1119.3769 da (fig. 6a) , corresponding to the molecular formula c 62 h 62 clfen 9 o 6 , suggesting the formation of 1:1 complex. thus, we propose that 5b interacts with heme by replacing chloride atom of hemin chloride and coordinating the iron atom with its endocyclic quinoline nitrogen as proposed in fig. 6b . similar titration of dimers of m-oxo type (10 mm) at ph 5.8 using standard procedure [29] with increasing concentration of compound 5b (0e14 mm), resulted in decrease in intensity of broad peak at 362 nm (fig. 7a, s1) . further, job's plot calculations indicated a 1:1 stoichiometry for the most stable m-oxo: 5b complex (fig. 7b) . in table 3 the association constants of 5b (log k 5.72) are compared to that of standard cq (log k 5.58) and also suggests that the binding of 5b is stronger with m-oxo heme (log k 5.72) than monomeric heme (log k 4.96). thus, the compound 5b inhibits hemozoin formation by blocking the growing face of heme resulting in the observed antimalarial activity. furthermore, the b-hematin inhibition assay (si table s2 ) shows that there is no correlation between antimalarial activity and b-hematin inhibition and also, all the compounds inhibit b-hematin formation although less than that of standard cq. the mechanism of many antimalarial drugs such as cq, quinacrine and quinine relies upon the interaction with dna presumably through ionic interactions between phosphate groups of dna and protonated amine in addition to the interactions between aromatic nuclei of the drug with nucleotide bases [40, 41] . therefore, the dna binding properties of 4-aminoquinolineepyrimidine hybrids have been evaluated using both the uvevisible spectrophotometer and fluorescence spectrophotometry in order to probe interaction of these compounds with dna. the addition of ct-dna (4e200 mm) to the buffered methanolic solution of 5b (30 mm) induced hyperchromic shift of 112% in absorption band at 255 nm whereas hypochromic shift of 37% in the characteristic quinoline ring absorption at 330 nm (fig. 8) . also, the bathochromic shift of w3 nm was observed for both the absorptions. the observed hyperchromic as well as hypochromic shifts in absorption bands of 5b upon addition of dna results from the intercalation of 5b with ct dna as suggested in the literature [42] . the intercalative nature of interaction of compound 5b with ct dna was additionally supported by thermal denaturation experiment. intercalation of molecules into the double helix is known to stabilize the dna against thermal strand separation and thus increases thermal melting temperature (t m ) [43, 44] . the derivative melting curve presented in fig. 9 shows an increase of 7.5 c in thermal melting temperature of ct dna upon addition of 5b which is less than that observed for the cq (table s3) . thus, both the uvevisible titrations and thermal denaturation experiment advocate partial intercalative nature of interactions between compound 5b and ct dna. further, to visualize the effect of dna base composition, the fluorescence titrations of 5b were performed with both gc-rich ct dna and at-rich puc18 dna in buffered methanol. fig. 10 shows decrease in the intensity of the emission band of 5b at 380 nm, upon addition of increasing concentration of both the dnas. a shift of 80 nm in emission band at 380 nm was observed upon addition of ct dna but no such shift in emission band was observed for puc18 dna. comparison of binding constant of 5b with ct dna (log k 5.76) and puc18 dna (log k 5.73) calculated from titration data using hypspec [39] , suggest that 5b does not discriminate between gc rich dna and at rich dna. a series of potent 4-aminoquinolineepyrimidine hybrids with antimalarial activity in nanomolar range were reported. the compound 5b exhibits lowest ic 50 value within the series against both cq s and cq r strains of p. falciparum. these hybrids displayed mild toxicity against mdck cell cultures. the antiviral activity profiles of these hybrids indicate that the compound 5a and 5c effectively inhibit feline corona virus and feline herpes virus. further, the mechanism of observed antimalarial activity was established in terms of binding with heme as well as dna. all liquid reagents were dried/purified following recommended drying agents and/or distilled over 4 a molecular sieves. thf was dried (na-benzophenone ketyl) under nitrogen. 1 h nmr (300 mhz) and 13 c (75 mhz) nmr spectra were recorded in cdcl 3 on a multinuclear jeol ft-al-300 spectrometer with chemical shifts being reported in parts per million (d) relative to internal tetramethylsilane (tms, d 0.0, 1 h nmr) or chloroform (cdcl 3 , d77.0, 13 c nmr). mass spectra were recorded at department of chemistry, guru nanak dev university, amritsar on a bruker lc-ms microtof ii spectrometer. elemental analysis was performed on flash ea 112 (thermo electron corporation) analyzer at department of chemistry, guru nanak dev university, amritsar and the results are quoted in %. ir spectra were recorded on perkin elmer ftir-c92035 fourier transform spectrometer in the range 400e4000 cm à1 using kbr pellets. melting points were determined in open capillaries and are uncorrected. for monitoring the progress of a reaction and for comparison purpose, thin layer chromatography (tlc) was performed on pre-coated aluminum sheets of merck (60f 254 , 0.2 mm) using an appropriate solvent system. the chromatograms were visualized under uv light. for column chromatography silica gel (60e120 mesh) was employed and eluents were ethyl acetate/ hexane or ethyl acetate/methanol mixtures. the steady state fluorescence experiments were carried out on perkin elmer ls55 fluorescence spectrometer at ambient temperature. uvevisible spectral studies were conducted on shimadzu 1601 pc spectrophotometer with a quartz cuvette (path length, 1 cm). the absorption spectra have been recorded between 1100 and 200 nm. the cell holder of the spectrophotometer was thermostated at 25 c for consistency in the recordings. to the stirred solution of 3 (2 mmol) and potassium carbonate (5 mmol) in dry thf (30 ml), a solution of appropriate 4aminoquinoline 4 (1.0 mmol) in dry thf (50 ml) was added. the reaction mixture was stirred for 48 h at room temperature. the reaction mixture was filtered and thf was removed under vacuum. the residue was purified by column chromatography using meoh/ ethyl acetate as eluent to obtain corresponding 5, which was recrystallized from dcm/hexane. using this procedure the following compounds were isolated. (for optimized structure of 5b, see figure s2 ). to the stirred solution of appropriate 4-aminoquinoline 4 in dry acetonitrile (50 ml) mixture of 3 (in a 1:2 molar ratio) and potassium carbonate in dry acetonitrile was added. the reaction mixture was refluxed for 24 h and then filtered. acetonitrile was removed under vacuum and the residue was purified by column chromatography using meoh/ethyl acetate as eluent to give 5 which is recrystallized from dcm/hexane. 6. material and methods the test samples were tested in triplicate on one or two separate occasions against chloroquine sensitive (cq s ) strain of p. falciparum (d10). continuous in vitro cultures of asexual erythrocyte stages of p. falciparum were maintained using a modified method of trager and jensen [45] . quantitative assessment of antiplasmodial activity in vitro was determined via the parasite lactate dehydrogenase assay using a modified method described by makler et al. [46] . the test samples were prepared to a 20 mg/ml stock solution in 100% dmso and sonicated to enhance solubility. samples were tested as a suspension if not completely dissolved. stock solutions were stored at à20 c. further dilutions were prepared on the day of the experiment. chloroquine (cq) was used as the reference drug in all experiments. test samples were initially tested at three concentrations (10 mg/ml, 5 mg/ml and 2.5 mg/ml) to determine the starting concentration for the full doseeresponse assay. cq was tested at three concentrations namely 30 ng/ml, 15 ng/ml and 7.5 ng/ml. a full doseeresponse was performed for all compounds to determine the concentration inhibiting 50% of parasite growth (ic 50 -value). test samples were tested at a starting concentration of 10 mg/ml, which was then serially diluted 2-fold in complete medium to give 10 concentrations; with the lowest concentration being 0.02 mg/ml. the same dilution technique was used for all samples. cq was tested at a starting concentration of 1000 ng/ml. several compounds were tested at a starting concentration of 1000 ng/ml. the highest concentration of solvent to which the parasites were exposed to had no measurable effect on the parasite viability (data not shown). the ic 50 -values were obtained using a non-linear doseeresponse curve fitting analysis via graph pad prism v.4.0 software. cytotoxicity was determined by exposing different concentrations of samples to vero, hel, hela and mdck cells [29] . the antiviral assays were based on inhibition of virus-induced cytopathicity in hel [herpes simplex virus type 1 (hsv-1), hsv-2 (g), vaccinia virus, and vesicular stomatitis virus], vero (parainfluenza-3, reovirus-1, coxsackie b4, and punta toro virus), hela (vesicular stomatitis virus, coxsackie virus b4, and respiratory syncytial virus) and mdck (influenza a (h1n1; h3n2) and b virus) cell cultures. confluent cell cultures in microtiter 96-well plates were inoculated with 100 cell culture inhibitory dose-50 (ccid 50 ) of virus (1 ccid 50 being the virus dose to infect 50% of the cell cultures) in the presence of varying concentrations of the test compounds. viral cytopathicity was recorded as soon as it reached completion in the control virus-infected cell cultures that were not treated with the test compounds [29] . shrinking the malaria map: progress and prospects thousands of chemical starting points for antimalarial lead identification artemisinin resistance in plasmodium falciparum malaria malaria chemotherapeutics, part i: history of antimalarial drug development, currently used therapeutics, and drugs in clinical development hybrid molecules with a dual mode of action: dream or reality? next-generation antimalarial drugs: hybrid molecules as a new strategy in drug design synthesis, antimalarial activity and cytotoxicity of 4-aminoquinolineetriazine conjugates synthesis of 4-aminoquinoline-1,2,3-triazole and 4-aminoquinoline-1,2,3-triazole-1,3,5-triazine hybrids as potential antimalarial agents synthesis and antimalarial activity in vitro and in vivo of a new ferroceneechloroquine analogue synthesis and biological evaluation of a new class of 4-aminoquinolineerhodanine hybrid as potent anti-infective agents synthesis and antimalarial activity of side chain modified 4-aminoquinoline derivatives enone-and chalconeechloroquinoline hybrid analogues: in silico guided design, synthesis, antiplasmodial activity, in vitro metabolism, and mechanistic studies preparation and antimalarial activities of trioxaquines, new modular molecules with a trioxane skeleton linked to a 4-aminoquinoline design, synthesis and anti-plasmodial evaluation in vitro of new 4-aminoquinoline isatin derivatives novel 4-aminoquinolineepyrimidine based hybrids with improved in vitro and in vivo antimalarial activity synthesis, characterization and antimalarial activity of quinolineepyrimidine hybrids substituted quinolinyl chalcones and quinolinyl pyrimidines as a new class of anti-infective agents falcipain-2 inhibitors quinoline antimalarial: mechanisms of action and resistance discovery of dual function acridones as a new antimalarial chemotype synthesis and antiviral activity of the alpha-analogues of 1,5-anhydrohexitol nucleosides facile transformation of 3,4-dihydropyrimidin-2(1h)-ones to pyrimidines in vitro evaluation as inhibitor of mycobacterium tuberculosis and modulators of cytostatic activity optimization of an anti-hiv hairpin ribozyme by in vitro selection adenosine kinase inhibitors. synthesis, water solubility, and antinociceptive activity of 5-phenyl-7-(5-deoxybeta-d-ribofuranosyl) pyrrolo[2,3-d]pyrimidines substituted at c4 with glycinamides and related compounds the synthesis of substituted pyridylpyrimidine fungicides using palladium catalysed crosscoupling reactions nucleoside analogues and nucleobases in cancer treatment synthesis and antiplasmodial activity of novel 2,4-diaminopyrimidines 2-aminopyrimidine based 4-aminoquinoline anti-plasmodial agents. synthesis, biological activity, structureeactivity relationship and mode of action studies ammonium chloride-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1h)-ones under solvent-free conditions an expedient protocol of the biginelli dihydropyrimidine synthesis using carbonyl equivalents on the reaction of 3,4-dihydropyrimidones with nitric acid. preparation and x-ray structure analysis of a stable nitrolic acid chloroquine analogues: influence of side chain length and quinolyl nitrogen pk a on activity vs chloroquine resistant malaria treatment of chronic active hepatitis b (cah b) with chloroquine: a preliminary report inhibition of human coronavirus 229e infection in human epithelial lung cells (l132) by chloroquine: involvement of p38 mapk and erk inhibition of human immunodeficiency virus infectivity by chloroquine mechanism of enhancement of the antiviral action of interferon against herpes simplex virus-1 by chloroquine malarial haemozoin/betahaematin supports haem polymerization in the absence of protein investigation of equilibria in solution. determination of equilibrium constants with the hyperquad suite of programmes chloroquine as intercalator: a hypothesis revived intercalating drugs: dna binding and molecular pharmacology cytotoxic activity, cell imaging and photocleavage of dna induced by a pt(ii) cyclophane bearing 1,2 diamino ethane as a terminal ligand spectrophotometric studies of the interaction of chloroquine with deoxyribonucleic acid spectroscopic studies on the thermodynamic and thermal denaturation of the ct-dna binding of methylene blue human malaria parasite in continuous culture parasite lactate dehydrogenase as an assay for plasmodium falciparum drug sensitivity we gratefully acknowledge financial assistance from csir, new delhi (project 01(2364)/10/emr-ii) and ugc, new delhi for special assistance programme (sap). h.k. thanks csir, new delhi for senior research fellowship. jb thanks ku leuven for financial support (goa 10/14). supplementary material associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.ejmech. 2013.05.046. key: cord-321985-w84wwkgi authors: xing, shihua; wang, mengyue; peng, ying; chen, daofeng; li, xiaobo title: simulated gastrointestinal tract metabolism and pharmacological activities of water extract of scutellaria baicalensis roots date: 2014-02-27 journal: j ethnopharmacol doi: 10.1016/j.jep.2013.12.056 sha: doc_id: 321985 cord_uid: w84wwkgi ethnopharmacological relevance: . scutellaria baicalensis: georgi (labiatae) is a well-known traditional chinese medicine to treat inflammation, cardiovascular diseases, respiratory and gastrointestinal infections, etc. the present study was to understand the metabolism of the root of scutellaria baicalensis (a.k.a. huangqin in chinese) in the gastrointestinal tract and the correlation between the metabolites and their respective pharmacological activities. materials and methods: the water extract of the root of scutellaria baicalensis (wesb) was incubated with simulated gastric and intestinal juices, and human fecal microflora for 24 h at 37 °c. the hplc–dad analysis was used to monitor the in vitro metabolic process and identify its metabolites by comparing their absorption spectrum and retention time with those of chemical references. the in vitro anticomplementary and antimicrobial activity was evaluated with hemolysis assay, agar disc-diffusion method and mic value, respectively. results: main constituents of wesb remain unchanged during the incubation with simulated gastric juice (ph=1.5) and intestinal juice (ph=6.8), whereas four flavones, baicalin, wogonoside, oroxyloside and norwogonoside were metabolized into their respective aglycons by human intestinal bacteria. all four metabolites were demonstrated to have higher anticomplementary and antimicrobial activity than those of wesb. the anticomplementary active metabolites were identified to be baicalein, oroxylin a and norwogonin, among them, norwogonin is the most active compound. conclusion: the presence of intestinal bacteria is demonstrated to play an important role in the gastrointestinal metabolism of wesb, and the pharmacological effects of scutellaria baicalensis may be dependent on the intestinal bacteria metabolism. the root of scutellaria baicalensis georgi (labiatae), also known as huangqin, is a widely used herb in traditional chinese medicine (tcm) with anticancer, antiviral, antibacterial and antiinflammatory properties (yoon et al., 2009) . traditionally, huangqin has been prescribed as a diuretic, laxative, febrifuge, an antipyretic, and for hemoptysis, bloody stool, and nasal haemorrhage when prescribed in a compound recipe (the pharmacopoeia commission of prc, 2010). remarkably, huangqin was recommended for the treatment and prevention of severe acute respiratory syndrome (sars) by the state tcm administration of the people 0 s republic of china (miller et al., 2005; zhang and chen, 2008) . huangqin was found to exert anti-inflammatory, antioxidant, anti-hepatitis b virus, anti-tumor, anti-allergic and anxiolytic properties (li et al., 2009; tong et al., 2012) . the main active constituents of huangqin are flavonoids, such as baicalin (baicalein-7-glucuronide), wogonoside (wogonin-7-glucuronide), baicalein, wogonin, oroxylin a and oroxyloside (oroxylin a-7glucuronide) (fig. 1 ). among these flavonoids, baicalin is regarded as the most important determinants of the quality of huangqin (yuan et al., 2011) . due to its orally administered as decoctions in tcm, the metabolism of the constituents often occurs in the gastrointestinal tract caused by the low gastric ph conditions, as well as the presence of digestive enzymes or intestinal bacteria (akao et al., 1994) . it was found that baicalin was initially hydrolyzed to baicalein prior to the absorption, while baicalein could be readily absorbed with a fast and extensive first pass metabolism (akao et al., 2000; lu et al., 2007) . wogonoside was found to be metabolized to wogonin by human fecal microflora (trinh et al., 2009 ). in addition, pharmacokinetic study of huangqin-tang decoction indicated that the constituents of wogonoside and oroxyloside had double-site absorption kinetics in rats which may due to the enteric circulation and enterohepatic circulation after oral dosing (zuo et al., 2003) . so far, there is no report on the metabolism of huangqin in gastrointestinal tract. in addition, most studies on bioactivity of huangqin were focused on antibacterial and anti-endotoxin activities but not anticomplementary activity. in this study, the water extract of huangqin, the root of scutellaria baicalensis (wesb) was incubated with simulated gastric and intestinal juices, and human fecal microflora, their metabolites were identified and the in vitro anticomplementary activity was evaluated. the inhibitory activity of main compounds in huangqin as well as their metabolites against the standard strains of methicillin-resistant staphylococcus aureus (mrsa), methicillin sensitive staphylococcus aureus (mssa), enterococcus faecalis (gram-positive bacteria), escherichia coli, pseudomonas aeuroginosa (gram-negative bacteria) was determined to understand the role of gastrointestinal tract conditions on pharmacological effects of huangqin. the roots of scutellaria baicalensis (huangqin) were purchased from leiyunshang drugstore (shanghai) and authenticated by one of the authors mengyue wang. voucher specimen (hn001) has been deposited at herbarium of school of pharmacy, shanghai jiao tong university, shanghai, china. pepsin (1: 250) and pancreatin were purchased from sangon biotech co., ltd (shanghai, china). general anaerobic medium broth (gam broth) was purchased from shanghai kayon biological technology co., ltd (shanghai, china). sheep erythrocytes, rabbit erythrocytes and anti-sheep erythrocyte antibody were purchased from shanghai fortune biological technological co., ltd (shanghai, china). heparin (sodium salt, 160 iu/mg) and macroreticular resin (hz-801) were purchased from china national medicines co., ltd (shanghai, china). normal human serum was obtained from healthy adult donors. guinea pigs serum was obtained from healthy guinea pigs from laboratory animal research center of fudan university. mrsa (atcc33591), mssa (atcc25923), enterococcus faecalis (atcc29212), escherichia coli (atcc8739), and pseudomonas aeuroginosa (atcc27853) provided by dr. xiuping qian 0 s lab. reference substances: baicalein, baicalin, wogonin, wogonoside, oroxylin a, oroxyloside were purchased from shanghai winherb medical technology co., ltd.; norwogonin was purchased from j&k chemical ltd.; norwogonoside was isolated from huangqin in our laboratory. all lab-made compounds were characterized by their spectra data, which were in accordance with references. all other chemicals and reagents were of analytical grade. dried huangqin (30 g) was decocted twice with a ten-fold mass of water to boil 1 h. after filtrated, the two filtrates were combined and then concentrated to 30 ml (equivalent to 1 g (crude drug)/ml). the hplc-dad analysis of wesb was conducted (fig. 2) . peaks 1-8 were confirmed by comparing the retention times and uv spectra with reference standards, and attributed to baicalin, norwogonoside, oroxyloside, wogonoside, norwogonin, baicalein, wogonin and oroxylin a, respectively. noted that norwogonoside was isolated from huangqin for the first time. a 0.4 ml wesb was placed in 5 ml simulated gastric juice (0.08 m hcl containing 50 mg pepsin, ph 1.5) and incubated at 37 1c for 0, 1, 2, 4 h, and the reactions were stopped by water saturated n-butanol immediately. the mixture was centrifuged at 4800 rpm for 20 min, and then the supernatant was evaporated. the residue was dissolved in 0.5 ml methanol, filtered through a 0.22 μm membrane and analyzed by hplc. repeat above all steps of experiment once more. a 0.4 ml wesb was placed in 5 ml simulated intestinal juice (0.05 m kh 2 po 4 containing 50 mg pancreatin, ph 6.8) and incubated at 37 1c for 0, 2, 4, 6 h. the treatment of samples was same to the simulated gastric juice. fresh fecal samples, obtained from five healthy subjects, were immediately homogenized with 25 volumes of gam broth. the sediments were removed by filtration through three pieces of gauze. the suspension was incubated at 37 1c in an anaerobic incubator in which the air had been replaced with a gas mixture (h 2 5%, co 2 10%, n 2 85%). a 1 ml wesb was added to human fecal suspension (100 ml) and the mixture was incubated at 37 1c in an anaerobic incubator for 24 h. the cultured mixture was respectively taken out and extracted with water saturated n-butanol. the extract was evaporated, and then the residue was dissolved in methanol (0.5 ml) and analyzed with hplc-dad. the hplc system consisted of a multi-solvent delivery pump (agilent 1200, usa), equipped with a quaternary solvent delivery system, an auto sampler and a dad detector. waters xterra reversed-phase column (particle size 5 μm, 4.6 mm â 250 mm i.d., agilent ltd., usa) were used. the purity of compounds and metabolic samples were analyzed under chromatographic condition as follows: acetonitrile (a)-water-phosphoric acid (100: appropriately. the addition of acid into the mobile phase was carried out in order to improve the peak shapes of analysis. uv absorption was monitored at 280 nm. the column temperature was set at 35 1c. the flow rate was 1.0 ml/min and sample injection volume was 10 μl. the dried huangqin (2.0 kg) were extracted for three times with 75% ethanol by heating reflux for 1.5 h each time, with the solvent removed under reduced pressure. the 75% ethanolic extract was suspended in water, and then purified with a column of macroreticular resin (column, 7.0 cm â 65 cm) washed with distilled water, 30% ethanol, 60% ethanol and 90% ethanol. the 60% ethanol soluble fraction (50 g) were firstly separated by silica gel column chromatography (12.0 cm â 70 cm, eluted with a gradient system of methanol and chloroform), and then by sephadex lh-20 column (2.5 cm â 70 cm, eluted with methanol) to obtain norwogonoside. 1 h and 13 c spectra data agree with those reported in the literature (shibata, 1988) . norwogonin-7-o-glucuronide yellow powder, the absorbance maximum (λ max ) of uv absorption is at 246, 285 and 357 nm in methanol, suggesting the compound to be a flavonoid. 1 h nmr (500 mhz, dmso-d6) δ: 12.23 (1h, s, 5-oh), 8.10-8.15 (2h, m, h2 0 , 6 0 ), 7.58-7.64 (3h, m, h3 0 , 5 0 ), 7.02 (1h, s, h-3), 6.65 (1h, s, h-6); 13 c nmr (125 mhz, dmso-d6) δ: 182.64 (c-4), 163.58 (c-2), 158.06 (c-7), 152.21 (c-9), 151.47 (c-5), 132.32 (c-4 0 ), 130.58 (c-1 0 ), 127.76 (c-8), 129.12 (c3 0 , 5 0 ), 126.56 (c-2 0 , 6 0 ), 105.13 (c-3), 105.56 (c-10), 99.36 (c-6). based on mayer's (1961) modified method, sensitized erythrocytes (ea) were prepared by incubation of sheep erythrocytes with rabbit anti-sheep erythrocyte antibody in gvb 2 þ (veronal buffer saline containing 0.1% gelatin, 0.5 mm mg 2 þ and 0.15 mm ca 2 þ ). the compounds and heparin sodium, used as reference, were dissolved in gvb 2 þ . guinea pigs serum was used as the complement source. the 1:40 diluted guinea pigs serum was chosen to give sub maximal lysis in the absence of complement inhibitors. first, various dilutions of tested samples (100 μl) were preincubated with 100 μl guinea pigs serum and 200 μl gvb 2 þ at 37 1c for 10 min. then, 200 μl ea was added and the mixture was incubated at 37 1c for 30 min. the different assay controls were incubated in the same conditions: (1) vehicle control, 200 μl ea in 400 μl gvb 2 þ ; (2) 100% lysis control, 200 μl ea in 400 μl water; (3) sample control, 100 μl dilution of each sample in 500 μl gvb 2 þ . the reaction mixture was centrifuged immediately. optical density of the supernatant was measured at 405 nm with a spectrophotometer (thermo, varioskan flash). the absorbance of sample (a 1 ), sample control (a 0 ) and 100% lysis control (a) were recorded. according to the method of klerx et al. (1983) , each sample was dissolved in gvb-mg-egta (veronal buffer saline containing 0.1% gelatin, 2.5 mm mg 2 þ and 8 mm ethylene glycol tetraacetic acid), and various dilutions were made. after pre-incubation of dilutions of each sample (150 μl) with 1:10 diluted normal human serum (150 μl) in enzyme label plate at 37 1c for 10 min, 200 μl rabbit erythrocytes (er) were added, followed a second incubation step at 37 1c for 30 min. after incubation, the resulting mixture was centrifuged immediately, and the optical density of the supernatant was measured at 405 nm. the inhibition rate of haemolysis was calculated by the following formula: a àða 1 à a 0 þ=a â 100%, where a, a 1 and a 0 represented the absorbance of 100% lysis control, the sample and the sample control, respectively. the ch 50 (concentrations resulted in 50% inhibition of sheep erythrocytes) or ap 50 (concentrations that resulted in 50% hemolysis inhibition of rabbit erythrocytes) value was obtained by plotting the hemolysis inhibition percentage against the logarithm of sample concentrations (lg c). heparin sodium salt was used as the positive control. 2.9. antibacterial activity by the agar disc-diffusion method and determination of minimal inhibitory concentration (mic) the antibacterial activity was carried out on wesb, metabolic sample incubated 24 h, the blank of intestinal bacterial liquid and eight flavonoids from huangqin with five test bacterial strains, and all of samples were three replicates. the positive controls were ampicillin for gram-positive bacteria, gentamycin for gramnegative bacteria and negative control was sterile distilled water. the antimicrobial effect of all samples was in petri dishes with 20 ml of nutrient agar plus 0.2 ml of microorganism suspension (10 8 cfu/ml, o.d 0.1, λ¼590 nm). once the agar had solidified, 200 ml of each sample and sterile distilled water (negative control) was added to wells of 3 mm diameter. the plates were incubated at 37 1c for 24 h, and the inhibited halos were evaluated (mm). the antibacterial effect was determined by measure of inhibited halos formed around the wells (murray et al., 1995; boussaada et al., 2008) . the mic value was determined by the dilution method according to national committee for clinical laboratory standards (1985) . the active samples and positive controls were dissolved in dimethylsulphoxide at a concentration of 2000 mg/ml. two fold serial dilutions of the solution were then prepared (2000, 1000, 500, …, 3.9 mg/ml). inoculated nutrient broth with 1% test bacteria strains (10 8 cfu/ml, o.d 0.1, λ¼590 nm) was prepared. ten concentrations of each sample â three test bacterial strains â three wells as repetitions were carried out in the sterile round-bottom 96-well plates by comparison of the sample with the non-inoculated nutrient broth. in each well, 0.9 ml inoculated nutrient broth plus 0.1 ml sample. plates were incubated at 37 1c for 24 h. the mic values were determined as the lowest concentration that inhibited visible growth of the bacterial as detected by unaided eye. wesb was found to be stable in simulated gastric juice (ph¼1.5) and intestinal juice (ph ¼6.8). after incubated with artificial juices, main constituents of wesb remained unchanged based on the comparison of peak areas of individual constituents during the course of incubation (rsd o3.0%). wesb was anaerobically incubated for 24 h with a bacterial mixture from human feces. the content changes of eight ingredients in wesb were analyzed at incubation time points of 0, 12 and 24 h. (fig. 3) . according to the content changes as well as the chemical structure of the eight ingredients in wesb, we concluded that four flavone glycosides, baicalin, wogonoside, oroxyloside and norwogonoside were converted to their respective aglycons, i.e. baicalein, wogonin, oroxylin a and norwogonin by intestinal bacteria. the effect on activation of guinea pig complement inhibition through the classical pathway was examined in 1:40 diluted guinea pig serum and heparin sodium was used as the positive control. the percent of activation that 1:40 diluted guinea serum occurred in the classical pathway was 98.34 75.23% in the complement control group. the percentage of activation that 1:10 diluted normal human serum occurred in the alternative pathway was 97.26 77.85% in the complement control group. wesb showed no anticomplementary effect through the classical pathway or alternative pathway. the ch 50 and ap 50 values of the metabolic samples at 24 h were both smaller than those of the blank of intestinal bacterial liquid as shown in fig. 4 . it indicated that the metabolic sample is more effective than the blank of intestinal bacterial liquid in complement inhibition. these results suggested that anticomplementary metabolites may be generated during the metabolic process. none of the flavonoid glycosides, baicalin, wogonoside, oroxyloside and norwogonoside, showed anticomplementary activities through the classical or alternative pathway, however, their respective metabolites, baicalein (ch 50 ¼0.18270.008 mg/ml; ap 50 ¼0.2437 0.013 mg/ml), oroxylin a (ch 50 ¼0.53670.032 mg/ml; ap 50 ¼ 0.83570.043 mg/ml) and norwogonin (ch 50 ¼0.13870.004 mg/ml; ap 50 ¼ 0.14770.008 mg/ml) did display an interesting anticomplementary activity through both classical and alternative pathways, while wogonin had no anticomplementary activity. remarkably, norwogonin demonstrated significant activity comparable to the positive inhibitor (heparin sodium, ch 50 ¼0.05670.005 mg/ml; ap 50 ¼0.07570.011 mg/ml). the primary antimicrobial screening was carried out using the agar disc-diffusion. as showed in fig. 5 , the wesb (1.25 mg/ml) had no inhibitory effect against any bacteria tested. the metabolic samples incubated for 24 h exhibited better antibacterial activity than the blank of intestinal bacterial liquid. specifically, baicalin, baicalein, wogonin and norwogonin revealed inhibitory effects against all bacteria studied, whereas oroxylin a was limited to mrsa, mssa and pseudomonas aeuroginosa, while wogonoside, oroxyloside and norwogonoside had no antimicrobial effect. the mic values of baicalin, baicalein, wogonin, oroxylin a and norwogonin against the bacteria were summarized in table 2 . norwogonin displayed an overall highest antimicrobial activity, followed by baicalein, oroxylin a and wogonin, and then baicalin. in order to identify the effective substances of huangqin by oral administration in human body, the metabolism in the gastrointestinal tract was investigated in vitro. although no change was observed in artificial gastric or intestinal juice, the main constituents, baicalin, wogonoside and oroxyloside, were found to be metabolized into their respective aglycons by intestinal bacteria. these findings are consistent with the reports that monomeric compounds baicalin, wogonoside and oroxyloside could be converted to metabolites baicalein, wogonin and oroxylin a by intestinal bacteria, respectively (akao et al., 2000; trinh et al., 2009; zuo et al., 2002) . the biotransformation of individual compound was the same as that in whole herb decoctions. moreover, a low content norwogonoside was isolated and identified from huangqin for the first time, and confirmed to be metabolized to norwogonin. baicalein, wogonin and oroxylin a were detected in rat plasma and urine samples after oral administration of gegen-qinlian-wan (gqw, including huangqin) by uhplc/dad/ qtof-ms, but not norwogonin which was present in our metabolic study in vitro (miao et al., 2013) . it is probably due to the difference between human and rat or the low content in specimens. nevertheless, both results suggest that flavonoid o-glycosides from huangqin could be easily transformed into their aglycones. the human complement system plays an important role in the host defense foreign invasive organisms. its effects are normally beneficial to the host (min et al., 2003) , but over-activation of the system may lead to pathological reaction in a variety of inflammatory and degenerative diseases such as rheumatoid arthritis, type i diabetes mellitus, systemic lupus erythematosus, sars, vasculitis and many others (valeriya et al., 2011) . numerous naturally occurring agents have been reported to effectively block the complement activation, which provide the prospect of novel anticomplementary drugs in non-toxicity based on abundant herb resources. the best described anticomplementary agents are polysaccharides, flavones and triterpenes (xu et al., 2007) . in the present study, wesb (1.25 mg/ml) showed no anticomplementary activity through the classical pathway or the alternative pathway, even though wesb was abundant in flavonoids. our studies on main flavonoid glycosides from wesb, baicalin, norwogonoside, oroxyloside and wogonoside generated the similar results (table 1) . however, their metabolites, especially norwogonin, showed obvious anticomplementary activity in inhibiting the classical pathway and the alternative pathway, suggesting a correction between 5,7-dihydroxyflavone and the anticomplementary effect. specifically, the inhibitory potencies against complement system were enhanced by the number of free hydroxyls on a ring of 5,7-dihydroxyflavone (xi et al., 2012) . this finding also agrees with the anticomplementary properties in some acylated flavonol glycosides obtained from magnolia fargesii (jung et al., 1998) and persicaria lapathifolia (park et al., 1999) . on the other hand, glycosylation on a ring of flavones might play an important role in its anticomplementary effect that most of the effect even disappeared (yao et al., 2013) . these results were also coincident with the previous suggestion that the intestinal flora might regulate the metabolism of compounds administered orally or excreted into bile (zuo et al., 2002) , and the herbal components should be transformed to bioactive compounds by the intestinal bacteria prior to their pharmacological actions (lee et al., 2002a; sousa et al., 2008) . further study should be carried out to elucidate their anticomplementary activity in vivo. published literature strongly support that the antimicrobial activities of some plant extracts are likely to be due to their high flavonoid content (cushnie and lamb, 2005; zhang et al., 2011) . in our studies, baicalin, baicalein, oroxylin a and norwogonin, four typical flavones possessed different degree of antimicrobial activities. a small number of research groups have investigated the relationship between structure and antibacterial activity of flavonoid to identify common structural features among active compounds. tsuchiya 0 s study indicated that 5,7-dihydroxylation of the a ring in the flavone structure was important for anti-mrsa activity (tsuchia et al., 1996) . it is consistent that baicalein, wogonin, oroxylin a and norwogonin, all featured such structures (shown in fig. 1) , and display better effective antimicrobial properties than other compounds. interestingly, a report by stapleton demonstrated that substitution with c-8 chain also enhanced the antistaphylococcal activity of flavonoids (stapleton et al., 2004) . independently, our data also revealed that norwogonin, 5,7,8-trihydroxyflavone has the highest antibacterial activity. these results suggest that the overall antimicrobial effect of huangqin may be dependent on its metabolism by intestinal bacteria. moreover, gram-negative bacteria escherichia coli and pseudomonas aeuroginosa have been inhibited to a less extent as compared to the gram-positive bacteria mrsa, mssa, and enterococcus faecalis as shown in table 2 . this result is in agreement with that flavonoids of the plant origin appear to have greater activity against gram-positive than gram-negative bacteria (ikigai et al., 1993) and could selectively inhibit gram-positive bacteria (wyman and van-etten, 1978) . further characterization of the interaction between these antimicrobial flavonoids and their target sites are needed, however. in the present study, norwogonin, one of the metabolites of wesb, presented most significant anticomplementary and antimicrobial activities. specifically, norwogonin has the most potent activity against multidrug-resistant acinetobacter baumannii strains (mic ¼0.256 mg/ml) among all identified antimicrobial compounds (miyasaki et al., 2013) , and exhibited more potent cytotoxicity than wogonin according to the mtt and ldh release assays in leukemia hl-60 cells (chow et al., 2008) . norwogonin also exhibited potent inhibitory activity toward vhr (ic 50 ¼ 1.1 μm), but had no inhibitory activity against t-cell protein tyrosine phosphatase or serine/threonine protein phosphatase 1 (lee et al., 2002b) . norwogonin possessed significant antioxidant activity in aaph (2,2 0 -azobis (2-amidinopropane hydrochloride)induced haemolysis (liu et al., 2004) . in addition, it is reported that norwogonin was determined in test strains differing in excision-repair capability and in the presence or absence of plasmid pkm101 (macgregor and wilson, 1988) . although some biological effects of norwogonin have been observed, the mechanism of action still remains unclear and requires further investigation. our results demonstrated that the presence of intestinal bacteria played an important role in the gastrointestinal metabolism of wesb. the process of metabolism by intestinal microbiota is involved in hydrolytic reactions generating non-polar low molecular weight byproducts. active metabolites were generated during the metabolic process. the results indicated that pharmacological effects of huangqin may be dependent on its metabolism by intestinal bacteria, consistent with the fact that wesb has no anticomplementary and antimicrobial activities in vitro. intestinal bacterial hydrolysis is indispensable to absorption of 18 beta-glycyrrhetic acid after oral administration of glycyrrhizin in rats baicalin, the predominant flavone glucuronide of scutellariae radix, is absorbed from the rat gastrointestinal tract as the aglycone and restored to its original form antimicrobial and antioxidant activities of methanol extracts of evax pygmaea (asteraceae) growing wild in tunisia differential apoptotic effect of wogonin and nor-wogonin via stimulation of ros production in human leukemia cells antimicrobial activity of flavonoids bactericidal catechins damage the lipid bilayer anticomplement activity of tiliroside from the flower buds of magnolia fargesi microassay for colorimetric estimation of 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phytochemical flavanones against methicillin-resistant staphylococcus aureus anti-inflammatory activity of devil 0 s claw in vitro systems and their active constituents antibacterial activity of selected isoflavonoids anti-complementary activity of flavonoids from gnaphalium affine d. don isolation and characterization of an anti-complementary polysaccharide d3-s1 from the roots of bupleurum smithii chemical constituents of rabdosia japonica var. glaucocalyx and their anti-complementary activity anti-inflammatory effects of scutellaria baicalensis water extract on lps-activated raw 264.7 macrophages high temperature effects on flavones accumulation and antioxidant system in scutellaria baicalensis georgi cells antioxidant and antiinflammatory activities of selected medicinal plants containing phenolic and flavonoid compounds anticomplementary principles of a chinese multiherb remedy for the treatment and prevention of sars metabolism of constituents in huangqin-tang, a prescription in traditional chinese medicine, by human intestinal flora pharmacokinetic study on the multi-constituents of huangqin-tang decoction in rats this work was financially supported by the national project in significant creation of new drugs during the eleventh five-year plan period (2009zx09502-013). the authors are grateful to dr. xiuping qian 0 s lab to provide all the bacteria strains and technical support of antimicrobial test, and dr. james l. fu for the careful english revision. supplementary data associated with this article can be found in the online version at http://dx.doi.org/10.1016/j.jep.2013.12.056. key: cord-267284-3uz0v29k authors: schneiderová, kristýna; šmejkal, karel title: phytochemical profile of paulownia tomentosa (thunb). steud. date: 2014-08-29 journal: phytochem rev doi: 10.1007/s11101-014-9376-y sha: doc_id: 267284 cord_uid: 3uz0v29k paulownia tomentosa, a member of the plant family paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in chinese herbal medicine. flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of p. tomentosa plant. recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. they show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. most of the compounds considered here have never been isolated from any other species of plant. this review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure–activity relationships that have been worked out for them. the plant paulownia tomentosa (thunb.) siebold & zucc. ex steud. is a very adaptable and extremely fastgrowing timber tree native to central and western china traditionally used in chinese medicine. this deciduous tree is now grown in many areas worldwide, mostly as a decorative ornamental tree (erbar and g} ulden 2011; zhu et al. 1986) . two related varieties of p. tomentosa have been described-var. tsinlingensis has a round to shallowly cordate leaf base and a glabrous or sparsely hairy lower leaf surface, whereas var. tomentosa is characterized by a cordate leaf blade base and an abaxial surface that is densely hairy when mature (hong et al. 1998) . paulownia was named paulownia in honour of anna paulowna (1795 paulowna ( -1865 , queen consort of the netherlands and a daughter of tsar paul i of russia. nowadays, it is commonly known under its synonym bignonia tomentosa (zhu et al. 1986) or as the princess-tree, empress-tree, foxglove tree, royal paulownia, kiri, or mao pao tong (yuan bian zhong) (erbar and g} ulden 2011; hong et al. 1998) . the genus paulownia was first assigned to family bignoniaceae by swiss botanist thunberg (1781). it was then transferred to the scrophulariaceae family by the dutch scholars zuccarini and siebold (1835) (zhu et al. 1986 ). at last, paulownia has been categorized as a family of its own, paulowniaceae, based on data from the latest molecular phylogenetic studies. this table 1 non-prenylated flavonoid aglycones isolated from p. tomentosa leaves (zhu et al. 1986 ) weak cytotoxic activity in vitro against human leukaemia (hl-60) and human hepatoma (smmc-7721) cell lines ; no a-glucosidase inhibitory effect (zhao et al. 2009 ); weak aldose-reductase inhibitory activity (kadota et al. 1994) ; moderate inhibitory effect on human immunodeficiency virus-1 protease (lee et al. 2008) ; no activity against lipopolysaccharide (lps)induced no production in raw 264.7 macrophages (li et (2) leaves , flowers jiang et al. 2004 ) antioxidant (prince vijeya singh et al. 2004 ); antibacterial, anti-inflammatory, antispasmodic, antidiarrhoic, antiproliferative, vasorelaxant (jiang et al. 2004 ); neuroprotective (losi et al. 2004 ); cardioprotective (psotová et al. 2004 ); chemopreventive activity against skin cancer ); activity reviewed by shukla and gupta (2009) and patel et al. (2007) h h oh h oh kaempferol (3) leaves (si et al. 2008a ) cytotoxic, pro-apoptic (suppresses cell metastasis via inhibition of the erk-p38-jnk and ap-1 signaling pathways in u-2 os human osteosarcoma cells) ; antioxidant (e.g., attenuates bladder hyperactivity caused by potassium chloride after protamine sulphate-induced bladder injury) (huang et al. 2014) ; impact on human health and cancer chemoprevention reviewed by , luteolin (4) leaves (si et al. 2008a; li 2011) memory-improving (yoo et al. 2013 ); inhibition of aamylase activity (funke and melzig 2005) ; cytotoxic (bgc-823 gastric carcinoma xenografts in nude mice) ; vascular protective (si et al. 2013 (5) bark (si et al. 2011b) , leaves (si et al. 2008a ) antifibrotic (yoon et al. 2012) ; antioxidant, antiproliferative, anti-inflammatory, cardioprotective ; neuroprotective (ghosh et al. 2013 ); anti-diabetic [dose-dependent inhibition of both na ? atpase and sodium hydrogen exchanger in type 2 diabetic erythrocytes (mishra and rizvi 2012) ; inhibition of pi3k (koch et al. 2013) ]; antiviral [anti hcv (khachatoorian et al. 2012) ; hcmv (cotin et al. 2012) ]; no anti-hiv activity in vitro tested on h9 cells in the absence of toxicity (tang et al. 1994 ); review of bioactivities by russo et al. (2012) oh h oh oh oh 7,3 0 -dimethylquercetin (syn. rhamnazin) leaves, green immature fruit (wollenweber et al. 2008 ) antimicrobial activity, poor antifungal effect (omosa et al. 2014 ); low antimicrobial activity, low toxicity against human lymphocytes and monocytes, antioxidant/antiinflammatory activity (martini et al. 2004; pelzer et al. 1998 ); low affinity to acetylcholinesterase (remya et al. 2012) ; low inhibitory effect on no production in raw264.7 cells (sudsai et al. 2013) ; no activity against hsv-1, low toxicity against vero cells (tian et al. 2009 ); no antioxidant activity (takamatsu et al. 2003) ; no trypanocidal activity (grael et al. 2000) ; activity against lipid peroxidation in rat liver microsomes (yun et al. 2000) ; cytotoxicity against tk-10, mcf-7 and uacc-62 cells (lopez-lazaro et al. 2000) ; no inhibition of glycolysis in various tumor cells (suolinna et al. 1975 ,4 0 -trimethylquercetin (7) thrombin inhibition (shi et al. 2012 ); inhibition of il-4 synthesis in basophils (hirano et al. 2006) ; weak trypanocidal activity (jordao et al. 2004 ); weak inhibition of no production in lps-activated mouse peritoneal macrophages (matsuda et al. 2003) ; weak inhibition of degranulation of rbl-2h3 cells (mastuda et al. 2002) ; inhibition of pgp activity (scambia et al. 1994) ; no inhibition of glycolysis in a variety of tumor cells (suolinna et al. 1975 flowers jiang et al. 2004; kim et al. 2010a , b) inactive against glutamate-induced neurotoxicity studied in primary-cultured rat cortical cells (kim et al. 2010a, b) ; no trypanocidal activity (grael et al. 2000) h h oh ome ome 5-hydroxy-7,3 0 flowers (kim et al. 2010a , b) inactive against glutamate-induced neurotoxicity studied in primary-cultured rat cortical cells (kim et al. 2010a, b) ; inhibition of inflammation by induction of synovial apoptosis of fibroblast-like synoviocytes through caspase 3 activation in rats with adjuvant arthritis (li et al. 2010 ; inhibition of jak2-stat3 signal pathway in rats ); inhibition of phosphodiesterase 4 (yang et al. 2011) ; low toxicity on b16f10 and sk-mel-1 melanoma cells (rodriguez et al. 2002) ; antimutagenic activity (miyazawa et al. 2000) h family includes only one genus and between six and ten species. it was originally introduced in 1949 by the research of nakai (erbar and g} ulden 2011) . biological activity and traditional uses of p. tomentosa extracts according to both legends and records, people were already using paulownia for various purposes about 2,600 years ago. chinese herbal medicine has used p. tomentosa traditionally to relieve bronchitis, especially by reducing coughing, asthma, and phlegm (zhu et al. 1986 ). it has also been used to treat conjunctivitis, dysentery, enteritis, erysipelas, gonorrhea, hemorrhoids, parotitis, traumatic bleeding, and tonsillitis (jiang et al. 2004; si et al. 2009 ). solutions prepared from the leaves and fruit extracted in water have been used in daily applications to promote the healthy growth of hair and turn grey hair dark. an extract prepared from the wood and leaves may relieve swollen feet. pharmacological experiments have shown that extracts from the fruit can reduce blood pressure. nowadays, injections and tablets prepared from paulownia flowers and fruit are used for the herbal treatment of chronic bronchitis and other kinds of inflammation (zhu et al. 1986 ). more than 130 physiologically active constituents have been isolated from different parts of the paulownia plant. their biological activity has been tested using both the isolated compounds and different types of extracts. for example, n-butanol, etoac, and meoh extracts obtained from the fruit have displayed antiradical activity in anti-dpph and peroxynitrite assays, due to mainly the presence of flavonoids and phenolic glycosides, but not of all compounds present in these extracts have been identified) (š mejkal et al. 2007b ). an meoh extract obtained from the fruit inhibited hache (ic 50 = 1.44 mg/ml) and bche (ic 50 = 0.97 mg/ml) significantly more strongly than chcl 3 and water extracts (possibly due to the content of phenolic glycosides and c-prenylated dihydroflavonols and flavanones) (cho et al. 2012 ). significant concentration-dependent anti-inflammatory properties of etoh extracts of the bark of the tree have also been observed recently using a lipopolysaccharide (lps)induced nitric oxide production inhibition model in the murine macrophages cell line raw264.7 (si et al. 2011a ). kim et al. (2010a, b) showed potential of aqueous extract of p. tomentosa to suppress glutamate induced toxicity in primary cultured rat cortical cells (with possible sesquiterpene lactone as active substance). the bio-activities of individual compounds and, where possible, the structure-activity relationships are in tables 1, 2, 3 and 4 and discussed in separate chapters. flavonoids represent the most numerous group of secondary metabolites isolated from p. tomentosa. they can be divided into simple non-prenylated flavonoids 1-18 (table 1) , c-prenylated and c-geranylated flavonoids 19-59 (tables 2, 3 , respectively), and flavonoid glycosides 60-65. compounds 16, 17, 19, 20, [25] [26] [27] [28] [29] [30] [31] [33] [34] [35] [36] have never been isolated from any other species. most of the isolated flavanones are characterized by a 2s configuration in contrast to the dihydroflavonols, for which 2r, 3r isomer is often observed. some of the flavonoid compounds found in p. tomentosa have been categorized as dietary flavonoids. consuming these compounds is believed to deliver health benefits. the activities of these flavonoids are frequently been reviewed, for example in the papers of romano et al. (2013) , marzocchella et al. (2011) , ross and kasum (2002) , and havsteen (2002) . some simple flavonoid substances isolated from fruit of p. tomentosa are commonly observed as the lipophilic components of different plant exudates. flavonoids 1-18 show broad-spectrum pharmacological activities (table 1) . many papers report their potential role as anticancer compounds for use against human cervical and breast (bulzomi et al. 2010 (bulzomi et al. , 2012 , hepatoma, leukemic , osteosarcoma , gastric carcinoma , colon adenocarcinoma (sánchez-tena et al. 2013) , or prostatic (zhang and coultas 2013) cancer cell lines. their antioxidant properties could explain their promising cardioprotective (paneerselvam et al. 2010; psotová et al. 2004 ) and neuroprotective effects (losi et al. 2004 ). antimicrobial (betts et al. 2013; jiang et al. 2004; mankovskaia et al. 2013 ) and antiviral (khachatoorian et al. 2012) bio-activities against different pathogens have also been discovered. in some cases, no specific biological activity has been observed (kim et al. 2010a (kim et al. , 2010b tang et al. 1994) . paulownia tomentosa is also a rich source of prenylated and geranylated flavonoids (19-59), whose occurrence is limited to relatively a few plant families (yazaki et al. 2009 ). there are sometimes misunderstandings in the naming of these compounds. a compound containing both a phenolic skeleton and a terpenoid side chain is often designated as a ''prenylated'' phenolic substance, even though it contains not a prenyl, but rather a geranyl or other type of terpenoid side-chain. prenylated flavonoids are biosynthesized by a combination of several pathways: the acetate, shikimate, and mevalonate ( fig. 1) . it is now known that the prenyl and geranyl moieties are biosynthesized via mevalonate or deoxyxylulose pathway. the connection of terpenoid and flavonoid biosynthetic antioxidant ; cytotoxic (a2780 human ovarian cancer cell line) (murphy et al. 2005 (murphy et al. , 2006 oh bark (sticher and lahloub 1982; zhu et al. 1986 ) antiphlogistic (choi et al. 2004 ), low cox-2/1 and 5-lox inhibition (wang et al. 2013; diaz lanza et al. 2001 kuzuyama et al. 2005) . the side chain can later be converted into different moieties by several reactions. it is unclear, whether the described modifications of the prenyl side-chain are natural-sunlight, the presence of oxygen and an elevated temperature can all affect the terpenoid metabolism-or are artefacts of isolation. some of the changes in the prenyl moiety have been observed after treatment of an extract, or during the separation of a mixture in the acidic environment of silica gel (navrátilová et al. 2013 ; š mejkal 2014) (fig. 2) . most of the prenylated flavonoids isolated from p. tomentosa belong to c-geranylated group of flavonoids (21-52). some of them have their sidechain further modified by hydroxylation (35-44, 50, 51, 53-59), methoxylation (45-47, 49, 50), oxidation (47, 48, 52), cyclization (51, 53-59), or reduction (19, 20, 47-52) . interestingly, these compounds have been isolated from the leaves, flowers and fruit, but they are most commonly isolated from the roots, root bark, or bark of different plants (botta et al. 2005) . compounds 23, 24, and 28 have been found in the yellow dendritic trichomes on the adaxial side of the p. tomentosa leaves. on the other hand, no significant detected concentration of secondary metabolites has been detected in the white dendritic trichomes on the adaxial side of the leaves or the brown dendritic trichomes on the flower buds ). glandular hairs found on the young reproductive organs of p. tomentosa are rich in flavonoids, with concentrations over 1,000 times greater than those on the surfaces of the young leaves . some seasonal variations in the appropriate time for harvesting the fruit have been discovered. autumn is the best time to obtain high concentrations of flavonoids whereas early summer is better for phenylpropanoid glycosides (holubová and š mejkal 2011) . the antioxidant š mejkal et al. 2007a, b; zima et al. 2010) , antibacterial (navrátilová et al. 2013; š mejkal et al. 2008b) , antiphlogistic , cytotoxic (kollár et al. 2011; š mejkal et al. 2007a , and severe acute respiratory syndrome coronavirus papain-like protease (sars-cov plpro) activities (cho et al. 2013 ) of isolated geranylated flavonoids have been described recently, together with their inhibitory effect on both human acetylcholinesterase and butyrylcholinesterase (cho et al. 2012) . the great ability of several geranylated flavanones to interact with bacterial sialidase isolated from clostridum perfringens (cp-nani), a bacterium causing various gastrointestinal diseases, has recently been reported (lee et al. 2014) . possible relationships between structure and activity have been proposed for each of these biological activities. nevertheless, it is difficult to evaluate real structure-activity relationships only by comparing the published studies, because the study conditions and the assays employed are often different. generally, the addition of an isoprenoid chain renders the derivate molecule more pharmacologically effective than the parent compound, probably because the prenyl group increases the lipophilicity and confers a strong affinity for biological membranes (botta et al. 2005; epifano et al. 2007; chen et al. 2014) . interestingly, neither the geranyl side-chain nor its substitution affects the antioxidant activity of flavonoids. the spatial arrangement of the substitution of the flavanone skeleton is more important. for example, the antiradical activity is increased by 2 0 -hydroxyl substitution of the ring b, whereas 4 0 -methoxyl substitution diminishes it. the general rules postulated for the antioxidant activity of flavonoids in vitro are applicable (havsteen 2002; chen et al. 2002) , there are many review publications that touch on this topic, and it is not aim of this paper to delve deeply into this (plaza et al. 2014) . the type of antioxidant assays used for the experiment could also be a factor that significantly affects this activity (zima et al. 2010) . numerous reports about structure related antimicrobial activity have been published, but comparison shows the results to be widely conflicting (cushnie and lamb 2005) . based on several studies, it has been postulated that hydroxylation at position c-5 or c-7 of ring a and positions c-2 0 or c-4 0 of ring b increases the antibacterial activity (š mejkal et al. 2008b; navrátilová et al. 2013) . however, contrary to this assumption, 45 and 50 had no significant antibacterial activity (navrátilová et al. 2013) . interestingly, some c-geranylated flavonoids do not able inhibit the growth of gram-negative bacteria (21, 22, 25-27, 35, 38, 45, 47-48, 50, 53, and 54) . resistance to these compounds is probably due to the more complex structure and hydrophilic nature of g-cell walls (navrátilová et al. 2013; š mejkal et al. 2008b) . furthermore, substitution of the geranyl side-chain with carbonyl, hydroxyl or methoxyl groups diminishes the antibacterial activity in a manner similar to what is seen when the geranyl substituent at c-6 forms a ring by reacting with the hydroxyl group at c-7. compounds 45, 47, 48, 50, 53 , and 54 exhibit some degree of activity in the range of the concentrations tested on the gram-positive bacteria staphyloccocus aureus and various methicillin resistant strains of s. aureus. the level of activity varied in depending on both the structure and the bacterial strain used in the assay. flavonoid structures like 24 are more effective in protecting plants from water loss because of their reduced polarity navrátilová et al. 2013). compounds 45, 47, 48, 50 , and 53 were also tested for their ability to affect the initiation of the eukaryotic translation via dual-luciferase reported assay (firefly and renilla), but only 45 showed a modest activity in comparison with anisomycin (navrátilová et al. 2013) . the cytotoxicity of the prenylated flavonoids obtained from p. tomentosa has been tested in more than 20 different cell lines. the type of prenylation strongly affects the cytotoxicity of a flavonoid in the traditional p-388 murine leukemia model. the unmodified 3-prenyl group and the presence of corresponding ortho-dihydroxy or trihydroxy substitution of the flavonoid ring b are crucial to its activity against p-388 as compared with other prenyl substituents (hakim et al. 1999 (hakim et al. , 2002 (hakim et al. , 2006 . similar findings have been observed for modified c-6 geranyl groups and the substitution of the ring b for other cell lines tested (š mejkal et al. 2010) . however, replacing the parahydroxy group of the ring b of a c-8 prenylated flavanone with several different acyl substituents resulted in greater cytotoxicity (aniol et al. 2012; š mejkal 2014) . it has also been found that cytotoxic activity is diminished by the presence of a c-3 hydroxyl substituent on the ring c, 4 0 -methoxy substitution of the ring b or a para-hydroxy substituted ring b (š mejkal et al. 2008a) . for this reason, it is important to emphasize that the relative importance of the substitution of ring b can differ according to the cell line used. modification of a prenyl or geranyl sidechain can not only change the direct cytotoxicity, but it may also affect the proliferation cells or trigger apoptosis (kollár et al. 2011; šmejkal et al. 2007a š mejkal 2014) . prenylated flavonoids 55-59, modified with an unusual 3,4-dihydro-2h-pyran moiety, have been found to inhibit the severe acute respiratory syndrome corona virus plpro enzyme more effectively than their parent compounds, the precursors from which were they derived (cho et al. 2013) . the presence of a geranyl group at the c-6 position (21, 22, 24-26, 30, 31, 33 , and 34) seems to be crucial for the hache and bche inhibitory effects. the most effective inhibitor was 22. all of the geranylated flavonoids, apart from 26, inhibited hache dosedependently. it appears that greater inhibition is observed when ring b of the flavanone bears free hydroxyl groups (cho et al. 2012 ). phytochem rev (2015 the crystal structure of the bacterial sialidase cp-nani catalytic domain in a complex with the geranylated flavonoid diplacone (22) provides structural insights into the binding mode of natural flavonoidbased inhibitors at atomic resolution. it shows how the geranyl and c-3 0 hydroxyl groups of 22 contribute to the stability of the enzyme-inhibitor complex. time-dependent competitive inhibition patterns have been observed. structural comparison of the human sialidases neu1-neu4 with the cp-nani-diplacone (22) complex suggests that the interaction between human sialidases and 22 is likely to be unfavourable because of polar or ionic repulsion (lee et al. 2014) . six flavonoid glycosides have been extracted from the stem bark 60-62 (si et al. 2009 ) and flowers 63-66 (scogin 1980) of p. tomentosa. apigenin-7-o-b-d-glucopyranoside (synonym: cosmosiin) (kurkina et al. 2011) (60) shows anti-hiv activity in vitro on h9 cells (tang et al. 1994 ) and enhances the secretion of adiponectin, the phosphorylation of the tyrosine residue of insulin receptor-b, and the translocation of glut5 (rao et al. 2011) . compound 60 shows no significant hepatic glc-6-phosphatase inhibitory activity in vitro (kumar et al. 2010 ). apigenin-7-o-b-d-glucuronopyranoside (61) was more potent than apigenin (2) and omeprazole in an assay analysing the inhibition of reflux esophagitis and gastritis promoted surgically and by application of indomethacine in rats (min et al. 2005) . no information about the biological activity of apigenin-7-o-[b-d-glucuronopyranosyl (1 ? 2)-o-b-d-glucuronopyranoside] (62) has been found in the literature. delphinidin-3-o-glucoside (synonym: myrtillin) (63) protects microglia from inflammationinduced stress signaling (carey et al. 2013) , is cytotoxic against the mcf-7 (breast) cancer cell line (vareed et al. 2006) , and has an the affinity for the estrogenic erb receptor (hidalgo et al. 2012 ). delphinidin-3,5-di-o-glucoside (64) and cyanidin-3,5-di-o-glucoside (65) are potent antioxidants tanaka et al. 2013) . compounds 63 and 65 are potent ace inhibitors in vitro (hidalgo et al. 2012; persson et al. 2009 ). only three lignans: (?)-paulownin (66), (?)-sesamin (67), (?)-piperitol (68) have been isolated from the wood of p. tomentosa (ina et al. 1987; takahashi and nakagawa 1966; zhu et al. 1986) (fig. 3 ). several reports have described their pharmacological effects pan et al. 2009 ). compound 66 is a promising antifungal agent that acts against the basidiomycetes fomitopsis palustris and trametes versicolor (kawamura et al. 2004) . sesamin (67) has been previously isolated from the wood of p. tomentosa, and p. kawakamii and the hybrid of p. elongata 9 p. fortunei (takahashi and nakagawa 1966; zhu et al. 1986 ). compound 67 is the major lignan in sesame, and has various biological activities, such as antioxidant, angiogenic (chung et al. 2010) , antiphlogistic (chatrattanakunchai et al. 2000) , antihypertensive (nakano et al. 2006) , insecticidal (nascimento et al. 2004) , neuroprotective , and anticarcinogenic ( . however, this compound showed no significant ability to reduce the formation of atherosclerotic lesions in the apoe (-/-) gene-knockout mouse, whereas specific dietary polyphenols, especially quercetin and theaflavin were more active (loke et al. 2010) . it has been suggested that some of the biological effects attributed to sezamine (67) may, in fact, be caused by its metabolites and that 67 may be acting as a proactive substance in the body (yasuda and sakaki 2012) . the metabolism of sesamim (67) by cytochrome p450 and udp-glucuronosyltransferase has been found remarkably different in humans as compared to other animals. further investigation into the safety of taking sesamin (67) with therapeutic drugs that are metabolised by cyp2c9 is also needed (yasuda and sakaki 2012) . a total of thirteen phenylpropanoid glycosides (69-81) with multifarious bioactivities, natural compounds derived biosynthetically from the amino acid phenylalanine, have been isolated from different parts of the p. tomentosa plant (table 4 ) (damtoft and jensen 1993; kang et al. 1994; ota et al. 1993; schilling et al. 1982; si et al. 2008b , d, si et al. 2011b sticher and lahloub 1982; šmejkal et al. 2007b; zhu et al. 1986 ). phenylpropanoids are of great interest for fabricating effective tonic, anticancer, hepatoprotective, immunostimulating, antimicrobial, and anti-inflammatory phytopreparations (kurkin 2003; galvez et al. 2006; panossian and wagner 2005; fu et al. 2008; pan et al. 2003) . a new furanoquinone, methyl-5-hydroxy-dinaphthol [1,2-2 0 ,3 0 ]furan-7,12-dione-6-carboxylate (mhddc) (82) (fig. 4) identified in p. tomentosa stem bark (meoh extract) has been shown to possess antiviral activity against poliovirus types 1 and 3, using hela cells in vitro (kang et al. 1999 ). its cathepsin k and l inhibitory activities in vitro have recently been discovered. the 5-oh functional group may have a favourable effect on this reduction potential which prevents the degradation of bone the matrix carried out by osteoclasts (park et al. 2009 ). the naphtoquinone plumbagin (83) has been detected in the leaves and fruit of p. tomentosa (babula et al. 2006) . it has been used in traditional systems of medicine since ancient times (pile et al. 2013) . it has exhibited promising antimalarial activity in vitro with ic 50 of 580 (270-640) nm and 370 (270-490) nm, respectively, against 3d7 chloroquine-sensitive p. falciparum and k1 chloroquineresistant p. falciparum clones, using an assay based on sybr green i. toxicity testing indicated relatively low toxicity at dose levels up to 100 mg/kg body weight (for a single oral dose) and 25 mg/kg (for daily dose given for consecutive 14 days) for acute and subacute toxicity, respectively. based on the results of in vivo antimalarial testing, plumbagin administered at a the dose of 25 mg/kg of body weight for 4 consecutive days exhibited moderate to weak antimalarial activity with regard to its ability to reduce parasitaemia and prolong survival time (sumsakul et al. 2014) . other published studies of plumbagin (83) described effects such as antifungal, antibacterial, cytotoxic (krishnaswamy and purushothaman 1980) , anticoagulant (santhakumari et al. 1978) , anthelmintic (antischistosomal) (zhang and coultas 2013) and an anti-inflammatory effect on the amelioration of experimental ulcerative colitis in mice at a dose of 8-10 mg/ kg (pile et al. 2013) . six iridoids: 7-b-hydroxyharpagide (84), paulownioside (85), catalpol (86), aucubin (87), tomentoside (88) and 7-hydroxytomentoside (89) have been isolated from the leaves of p. tomentosa (84-87) (adriani et al. 1981; franzyk et al. 1999) , the bark of the trunk and roots (86) (plouvier 1971 ) and parts of the young plant (85, 86, 88, and 89) (damtoft and jensen 1993) (fig. 5) . compound 86 shows neuroprotective activity (li et al. 2004 ), a cardioprotective effect against myocardial infarction-specifically reperfusion damage (huang et al. 2013a, b) , and radioprotective effects . it also increases glucose utilization by increasing the secretion of b-endorphin from the adrenal gland (shieh et al. 2011) . compounds 86 and 87 possess antispasmodic activity (deurbina et al. 1994) . aucubin (87) had antioxidant and pancreasprotective effects on streptozotocin-induced diabetes in rats (jin et al. 2008) and it may improve obesityinduced atherosclerosis by attenuating the tnf-ainduced inflammatory response (park 2013) . a weak antibacterial effect (against streptococcus pneumoniae and mg-hemolytic streptococcus, mic 28.946 mg/ml) (zheng et al. 2012 ) and neuroprotective effects of 87 on diabetes and diabetic encephalopathy (xue et al. 2012) have also been observed. the sesquiterpenic lacton isoatriplicolide tiglate (90) has been isolated from p. tomentosa flowers. it has neuroprotective effects against glutamate-induced neurotoxicity (kim et al. 2010a (kim et al. , 2010b and cytotoxic activity against several cancer cell lines: a549 lung carcinoma; sk-ov-3 adenocarcinoma; sk-mel-2 malignant melanoma; xf498 central nervous system tumors; hct15 colon adenocarcinoma, against which its effect is comparable to that of reference substance adriamycin (moon and zee 2001) ; human breast cancers mda-mb-231, mcf7, hs578t, and t47d; and the hela, siha and c33a cervical cancer cell lines (jung et al. 2012) . seven phytosterols have been isolated from p. tomentosa leaves: ursolic acid (91) (zhu et al. 1986; zhang and li 2011) , 3-epiursolic acid (92), pomolic acid (93), corosolic acid (94), maslinic acid (95), b-sitosterol (96), and daucosterol (97) (zhang and li 2011) . most of these show various biological activities, e.g., 91 is a potentially useful for treating alzheimer's disease (because of its ability to block the interactions of the amyloid b-cd36) (wilkinson et al. 2011) . it can prevent the recruitment of the monocytes that accelerate atherosclerosis, a major complication of diabetes, in mice (ullevig et al. 2011) , and it also possesses antibacterial (wong et al. 2012) , anti-trypanosomal, and anti-leishmanial properties (bero et al. 2011) . compound 91 has also shown cytotoxic effects against k562 and k562/adr human chronic myelogenous leukaemia, hl60 and hl60/adr human acute myelocytic leukemia cancer cells, and the human colon cancer cell lines sw480 and sw620 (shan et al. 2011) . compounds 93-96 also show promising cytotoxic potential, e.g., 93 is effective against the human chronic myelogenous leukaemia cell line 562 and also against cells derived from chronic myeloid leukaemia patients (vasconcelos et al. 2007 ). compound 94 shows cytotoxic effects against osteosarcoma mg-63 cells (cai et al. 2011) and immunosuppressive activity on myeloid-derived suppressor cells in the murine sarcoma model (horland et al. 2013 (deepak and handa 2000) , and 93 (schinella et al. 2008 ). an immunomodulatory effect of 97 in protecting mice against candidiasis disseminated by the cd4? th1 immune response has been seen (lee et al. 2007 ). other recently discovered pharmacological effects include antimalarial (95) (moneriz et al. 2011) , hypotensive and endothelium-dependent vasorelaxant effects (93) (estrada et al. 2011 ). compound 95 is potentially useful for treating cerebral ischemic injuries (guan et al. 2011) , and 94 has promising antidiabetic effects (sivakumar et al. 2009 ). (127). the relatively most abundant constituents were 111 (20 % of the total glycerides), 126 (14 %), and 120 and 127 (12 %) (asai et al. 2009 ). another analysis of the secretions of the glandular hairs on the leaves of both bud flushes and adult trees as well as the flowers of adult trees showed that these secretions contain ten glycerides (106, 108-110, 118, 122, 124-127) . these compounds showed sticky character, but they were not toxic to several insects. therefore, the glandular hairs on the leaves and flowers may serve only to physically deter herbivores (fig. 6) . six known phenolic acids, namely p-hydroxybenzoic acid (128), vanillic acid (129), gallic acid (130), cinnamic acid (131), p-coumaric acid (132), and caffeic acid (133) have been identified in the leaves of p. tomentosa (128-133), bark (130 and 131) and wood (133) (ota et al. 1993; si et al. 2008c si et al. , 2011b , and p-ethoxybenzaldehyde (134) is present in flowers (yuan et al. 2009 ). the 5,7-dihydroxy-6-geranylchromone (135) isolated from fruits shows only moderate cytotoxic activity against a suspension culture of nicotiana tabacum cv. bright yellow (by-2), which confirms that ring b of the flavonoid skeleton is important for this activity (š mejkal et al. 2008a) . a large group of essential oil substances found in the flowers of p. tomentosa have also been identified (oprea et al. 2004; ibrahim et al. 2013) (fig. 7) . plants are still highly esteemed all over the world as rich sources of therapeutic agents. in this context, traditional chinese herbal medicines, such as paulownia continue to influence a modern healthcare. it has been estimated that approximately 420,000 plant species exist on earth, but little is known about the phytochemical or therapeutic qualities of most of them. thanks to the development of the spectral and other analytical methods used in modern phytochemistry, many of the principal physiologically active secondary metabolites have been identified and researched in detail. the accumulated knowledge of traditional medicine is therefore, playing an important role in enhancing the success of drug discovery in herbal medicine. approximately 80 % of the currently known antimicrobial, cardiovascular, immunosuppressive, and anticancer drugs are of plant origin (pan et al. 2013) . as mentioned in this review, p. tomentosa is a rich source of multifarious secondary metabolites, mainly prenylated flavonoids. as of today 135 compounds, including flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and other miscellaneous compounds have been isolated from various extracts of this plant. of increasing interest are the isolation and identification of p. tomentosa prenylated flavonoids, as they have shown promising pharmacological effects. in the first experiments, their antioxidant, antibacterial, antiphlogistic, cytotoxic, and sars-cov pl activities have been discovered along with inhibitory effects on human acetylcholinesterase, butyrylcholinesterase, and bacterial neuraminidases. more than 40 compounds with modified prenyl or geranyl side-chains attached at c-6 of the flavonoid skeleton have been isolated from the flowers, fruit, and leaves of p. tomentosa. only two of these compounds have shown the presence of a five-carbon side-chain; for the others a ten-carbon side-chain is typical. further, only a few compounds have shown a geranyl moiety modified by hydroxylation at c-6 00 or c-7 00 . some compounds have a geranyl group modified by formating a heterocyclic moiety, which is also unusual. most of them have never been isolated from any other plant species. however, further in vivo pharmacology studies are needed to precisely elucidate biological mechanism of action, efficacy, and toxicity of these promising therapeutic agents. elucidation of the structure-activity relationships is also crucial for their further total syntheses and introduction into medical practice. for these reasons, the study of p. tomentosa as a source of biologically active metabolites is significant and future interest in this plant is ensured. isolation and characterization of paulownioside, a new highly oxygenated iridoid glucoside from paulownia tomentosa acteoside: a new antihypertensive drug in vitro immunomodulatory activity of verbascoside from nepeta ucrainica l antiproliferative activity and synthesis of 8-prenylnaringenin derivatives by demethylation of 7-o-and 4 0 -o-substituted isoxanthohumols effects of taxifolin on the activity of angiotensin-converting enzyme and reactive oxygen and nitrogen species in the aorta of aging rats and rats treated with nitric oxide synthase inhibitor and dexamethasone geranylated flavanones from the secretion on the surface of the immature fruits of paulownia tomentosa acylglycerols (=gly-cerides) from the glandular trichome exudate on the leaves of paulownia tomentosa chromatografické stanovení naftochinonů v rostlinách (chromatographic evaluation of naphtochinones in plants) active components from siberian ginseng (eleutherococcus senticosus) for protection of amyloid b(25-35)-induced neuritic atrophy in cultured rat cortical neurons catechin prodrugs and analogs: a new array of chemical entities with improved pharmacological and pharmacokinetic properties in vitro antitrypanosomal and antileishmanial activity of plants used in benin in traditional medicine and bio-guided fractionation of the most active extract antifungal synergy of theaflavin and epicatechin combinations against candida albicans prenylated flavonoids: pharmacology and biotechnology antiproliferative effect of catechin in grx cells naringenin and 17b-estradiol coadministration prevents hormone-induced human cancer cell growth the naringenininduced proapoptotic effect in breast cancer cell lines holds out against a high bisphenol a background corosolic acid triggers mitochondria and caspase-dependent apoptotic cell death in osteosarcoma mg-63 cells stilbenes and anthocyanins reduce stress signaling in bv-2 mouse microglia investigation of two flacourtiaceae plants: bennettiodendron leprosipes and flacourtia ramontchi cardiovascular protective flavonolignans and flavonoids from calamus quiquesetinervius sesamin inhibits lysophosphatidylcholine acyltransferase in mortierella alpine a review of the dietary flavonoid, kaempferol on human health and cancer chemoprevention structure-activity relationship of natural flavonoids in hydroxyl radicalscavenging effects propolin c from propolis induces apoptosis through activating caspases, bid and cytochrome c release in human melanoma cells determination of flavonoids in the flowers of paulownia tomentosa by high-performance liquid chromatography chemical modification and anticancer effect of prenylated flavanones from taiwanese propolis radio-protective effect of catalpol in cultured cells and mice a systematic review on biological activities of prenylated flavonoids cholinesterase inhibitory effects of geranylated flavonoids from paulownia tomentosa fruits geranylated flavonoids displaying sars-cov papain-like protease inhibition from the fruits of paulownia tomentosa anti-inflammatory and antinociceptive effects of sinapyl alcohol and its glucoside syringin angiogenic activity of sesamin through the activation of multiple signal pathways eight flavonoids and their potential as inhibitors of human cytomegalovirus replication antimicrobial activity of flavonoids tomentoside and 7-hydroxytomentoside, two new iridoid glucosides from paulownia tomentosa antimicrobial activity of brazilian propolis extracts against rumen bacteria in vitro antiinflammatory activity and chemical composition of extracts of verbena officinalis studies on the vascular effects of the fractions and phenolic compounds isolated from viscum album ssp. album in vitro antispasmodic activity of peracetylated penstemoniside, aucubin and catalpol lignan and phenylpropanoid glycosides from phillyrea latifolia and their in vitro anti-inflammatory activity phenolic compounds from artemisia iwayomogi and their effects on osteoblastic mc3t3-e1 cells chemistry and pharmacology of oxyprenylated secondary plant metabolites ontogeny of the flowers in paulownia tomentosa-a contribution to the recognition of the resurrected monogeneric family paulowniaceae pomolic acid of licania pittieri elicits endotheliumdependent relaxation in rat aortic rings dietary flavonoids: role of (-)-epicatechin and related procyanidins in cell signaling halohydrins of antirrhinoside-the correct structures of muralioside and epimuralioside naturally occurring phenylethanoid glycosides: potential leads for new therapeutics dietary flavonol epicatechin prevents the onset of type 1 diabetes in nonobese diabetic mice effect of different phenolic compounds on a-amylase activity: screening by microplatereader based kinetic assay pharmacological activities of phenylpropanoids glycosides neuroprotective role of nanoencapsulated quercetin in combating ischemiareperfusion induced neuronal damage in young and aged rats hepatoprotective effects of syringin on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice a study of the trypanocidal and analgesic properties [of substances] from lychnophora granmongolense (duarte) semir & leitao filho maslinic acid, a natural inhibitor of glycogen phosphorylase, reduces cerebral ischemic injury in hyperglycaemic rats by glt-1 up-regulation studies on b-sitosterol and ceramideinduced alterations in the properties of cholesterol/sphingomyelin/ganglioside monolayers artoindonesianins a and b, two new prenylated flavones from the root of artocarpus champeden artoindonesianin p, a new prenylated flavone with cytotoxic activity from artocarpus lanceifolius prenylated flavonoids and related compounds of the indonesian artocarpus (moraceae) the biochemistry and medical significance of the flavonoids advanced research on acteoside for chemistry and bioactivities potential anti-inflammatory, anti-adhesive, anti/estrogenic, and angiotensin-converting enzyme inhibitory activities of anthocyanins and their gut metabolites luteolin, a flavonoid, inhibits ap-1 activation by basophils changes in the level of bioactive compounds in paulownia tomentosa fruits corosolic acid impairs tumor development and lung metastasis by inhibiting the immunosuppressive activity of myeloid-derived suppressor cells effect of diplacone on lps-induced inflammatory gene expression in macrophages prenylated and geranylated flavonoids increase production of reactive oxygen species in mouse macrophages but inhibit the inflammatory response catalpol decreases peroxynitrite formation and consequently exerts cardioprotective effects against ischemia/reperfusion insult eleutheroside b or e enhances learning and memory in experimentally aged rats anti-oxidant activity and attenuation of bladder hyperactivity by the flavonoid compound kaempferol chemical composition, antimicrobial activity of the essential oil of the flowers of paulownia tomentosa (thunb.) steud. growing in egypt antiplatelet aggregatory effects of the constituents isolated from the flower of carthamus tinctorius piperitol from paulownia tomentosa antiinflammatory role of naringenin in rats with ethanol induced liver injury determination of flavonoids from paulownia tomentosa (thunb) steud. by micellar electrokinetic capillary electrophoresis phenylethanoid glycosides in plants: structure and biological activity antioxidant and pancreasprotective effect of aucubin on rats with streptozotocininduced diabetes trypanocidal activity of chemical constituents from lychnophora salicifolia mart inhibitory effect and mechanism on antiproliferation of isoatriplicolide tiglate (pcac) from paulownia coreana matteuorienate a and b, two new and potent aldose reductase inhibitors from matteuccia orientalis (hook.) trev antibacterial phenylpropanoid 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antidepressant activity of some phytopharmaceuticals and phenylpropanoids flavonoids from tanacetum vulgare flowers structural basis for the promiscuous biosynthetic prenylation of aromatic natural products immunoregulatory activity of daucosterol, a beta-sitosterol glycoside, induces protective th1 immune response against disseminated candidiasis in mice two new triterpenes from the rhizome of dryopteris crassirhizoma, and inhibitory activities of its constituents on human immunodeficiency virus-1 protease anti-inflammatory effect and hplc analysis of extract from edible cirsium setidens anthocyanin compositions and biological activities from the red petals of korean edible rose (rosa hybrid cv. noblered) structural basis of sialidase in complex with geranylated flavonoids as potent natural inhibitors neuroprotection of catalpol in transient global ischemia in gerbils 0 -dimethoxy hesperetin induces apoptosis of fibroblast-like synoviocytes in rats with adjuvant arthritis through caspase 3 activation phenolic compounds of abies nephrolepis and their no production inhibitory activities therapeutic effect of 7,3 0 -dimethoxy hesperetin on adjuvant arthritis in rats through inhibiting jak2-stat3 signal pathway 0 -dimethoxy hesperetin inhibits inflammation by inducing synovial apoptosis in rats with adjuvant-induced arthritis the inhibitory effect of phenylpropanoid glycosides and iridoid glucosides on free radical production and b2-integrin expression in human leucocytes anti-inflammatory effect of the 5,7,4 0 -trihydroxy-6-geranylflavanone isolated from the fruit of artocarpus communis in s100b-induced human monocytes release of acetylcholine by syringin, an active principle of eleutherococcus senticosus, to raise insulin secretion in wistar rats specific dietary polyphenols attenuate atherosclerosis in apolipoprotein e-knockout mice by alleviating inflammation and endothelial dysfunction distribution and biological activities of the flavonoid luteolin cytotoxic activity of flavonoids and extracts from retama sphaerocarpa boissier apigenin modulates gabaergic and glutamatergic transmission in cultured cortical neurons inhibitory effects of luteolin on human gastric carcinoma xenografts in nude mice and its mechanism catechinincorporated dental copolymers inhibit growth of streptococcus mutans biological activity of five antibacterial flavonoids from erythrophyllum (combretaceae) dietary flavonoids: molecular mechanisms of action as anti-inflammatory agents structural requirements of flavonoids for inhibition of antigeninduced degranulation, tnf-a and il-4 production from rbl-2h3 cells studies on physiologically active substances in citrus fruit peel. part xx. structure and physiological activity of phenyl propanoid glycosides in lemon (citrus limon burm. f.) peel structural requirements of flavonoids for nitric oxide production inhibitory activity and mechanism of action the endocrine activities of 8-prenylnaringenin and related hop (humulus 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b-endorphin secretion by syringin, an active principle of eleutherococcus senticosus, to produce antihyperglycemic action in type 1-like diabetic rats role of sympathetic tone in the loss of syringin-induced plasma glucose lowering action in conscious wistar rats hypoglycemic effect of syringin from eleutherococcus senticosus in streptozotocin-induced diabetic rats antileishmanial phytochemical phenolics: molecular docking to potential protein targets antimicrobial flavonoids and diterpenoids from dodonaea angustifolia the analysis of the volatile and semi-volatile compounds of the paulownia tomentosa flowers by gas chromatography coupled with mass spectrometry the chemistry of color changes in kiri wood (paulownia tomentosa steud.) iii. a new caffeic acid sugar ester from kiri wood pharmacological activities and mechanisms of natural phenylpropanoid glycosides an update on lignans: natural products and synthesis bioactive constituents from chinese natural medicines. xxxvi. four new 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the chemical constituents from the leave of paulownia tomentosa antitumor activities of extracts and compounds from the roots of daphne tangutica maxim new lignans and their biological activities glucosidase inhibitory constituents from toona sinensis isolation, modification and cytotoxic evaluation of flavonoids from rhododendron hainanense enzymatic extraction and antibacterial activity from eucommia ulmoides leaves paulownia in china: cultivation and utilization. asian network for biological science and international development research centre, chinese academy of forestry antiradical and cytoprotective activities of several c-geranyl-substituted flavanones from paulownia tomentosa fruit key: cord-300522-okbupw61 authors: sansone, clementina; brunet, christophe; noonan, douglas m.; albini, adriana title: marine algal antioxidants as potential vectors for controlling viral diseases date: 2020-05-07 journal: antioxidants (basel) doi: 10.3390/antiox9050392 sha: doc_id: 300522 cord_uid: okbupw61 as the covid-19 epidemic expands in the world, and with the previous sars epidemic, avian flu, ebola and aids serving as a warning, biomedical and biotechnological research has the task to find solutions to counteract viral entry and pathogenesis. a novel approach can come from marine chemodiversity, recognized as a relevant source for developing a future natural “antiviral pharmacy”. activities of antioxidants against viruses can be exploited to cope with human viral infection, from single individual infections to protection of populations. there is a potentially rich and fruitful reservoir of such compounds thanks to the plethora of bioactive molecules and families present in marine microorganisms. the aim of this communication is to present the state-of-play of what is known on the antiviral activities recognized in (micro)algae, highlighting the different molecules from various algae and their mechanisms of actions, when known. given the ability of various algal molecules—mainly sulfated polysaccharides—to inhibit viral infection at stage i (adsorption and invasion of cells), we envisage a need to further investigate the antiviral ability of algae, and their mechanisms of action. given the advantages of microalgal production compared to other organisms, the opportunity might become reality in a short period of time. the ongoing global emergency linked to the covid-19 pandemic [1] teaches us that viral diseases can be dramatic all over the world in the present period of climate, political, social and globalization change. scientific solutions were not available and society was unprepared, claiming that research activities for the discovery of compounds for the prevention and treatment of severe and acute viral infections are nowadays a priority. oxidative stress-a loss in the balance between the production of free radicals including reactive oxygen species (ros) and antioxidant cell signaling pathways [2] -can be a key factor of the pathogenesis in many acute or chronical human diseases [3] . dietary intake of exogenous antioxidants in humans has a well-known role in preventing and protecting cellular oxidative stress. they operate diverse mechanisms of action and possess different therapeutic effects. as a result, modern medicine tends to use them in the prevention and treatment of various oxidative-stress-associated diseases [4] . viral infections are promoted by oxidative processes, the latter acting on replication in infected cells, cell proliferation inhibition and cell apoptosis induction [5] . in patients affected by herpes simplex [6] , it was observed that an increase of the ros-induced membrane phospholipids peroxidation caused dysfunction of vital cellular processes such as membrane transport and mitochondrial respiration [7] . epstein-barr virus (ebv) infections cause an increase in dna damage and significant ros accumulation, and, interestingly, treatment with ros scavengers was able to lower dna damage in both mitogen-stimulated and ebv-infected cells [8] . in this framework, discovery and screening of antioxidant compounds with antiviral properties is promising since the treatment of viral diseases requires the suppression of viral replication and cell survival promotion. the most known ros scavenger compounds belong to different chemical families, such as polyphenols (phenolic acids, flavonoids, anthocyanins, lignans and stilbenes), carotenoids (xanthophylls and carotenes), sterols, or vitamins (vitamins b, d, e, and c) [9] . for instance, there is a lot of evidence of the capability of natural antioxidants such as vitamins c and e (ascorbic acid and tocopherol, respectively) or polyphenols (e.g., curcumin) scavenging ros levels in infected cells, inhibiting proapoptotic factors and thus reestablishing the intracellular equilibrium between the stress-related proteins (such as c-jun n-terminal kinases-jnk) and promitotic (mapk) and transcription factors (nf-kb) [10] [11] [12] [13] . the most effective antioxidants are mainly synthetized by photosynthetic organisms, sharing these precious compounds with herbivorous animals through diet, and bioaccumulating along the trophic web [14] , as occurs in marine systems [15] . indeed, marine organisms represent a rich source of antioxidants, in terms of quantity and/or diversity. vitamins b 12 , c, d, e, peptides, amino acids, chitooligosaccharide derivatives, carotenoids, sulphated polysaccharides, sterols, phlorotannins, phenolic compounds and flavones are examples of marine antioxidant richness [16] . it is not surprising, therefore, that marine pharmacology is increasingly growing. recently, mayer et al. [17] reported that 21 studies were published in 2014/2015, focusing on marine antiviral drugs acting against human enterovirus 71, human cytomegalovirus, human immunodeficiency virus type-1 (hiv-1), human herpes simplex virus (hsv), influenza virus, hepatitis b virus, murine norovirus, respiratory syncytial virus (rsv) or sindbis virus. the mechanism of action of these compounds is known for five of them, although for the others it is still undetermined [17] . the aim of the present study is to show the state of the art, exploring the potential antiviral activity of known marine antioxidant compounds. for that, we explore the relationship between oxidative stress and viral infections, looking for solutions through the deciphering of cell signaling pathways that can inhibit virus replication and infections, and the mechanisms of action of potential antiviral molecules. the global public health emergency of international concern by 30 january 2020 regards the novel coronavirus [18] , which is the direct cause of the severe pneumonia (covid-19), with a high rate of transmission and infectivity. the 85% of critically ill patients with covid-19 showed leukocytosis, high levels of monocytes and neutrophils, and lymphopenia [19] , which is a lack of lymphocytes, with patients dying with comorbidity and high levels of plasma cytokines [20] . lymphopenia and hypercytokinemia are directly correlated with increased severity, mortality and a dysregulated immunological response [21] . first epidemiological indications reveal that the covid-19 patients requiring intensive care are older and are more likely to have hypertension, diabetes, cardiovascular or cerebrovascular pathologies [22] . aging and chronic diseases induce chronic endothelial dysfunction that provokes disassembly of intercellular junctions, endothelial cell death and blood-tissue barrier disruption, along with enhanced leukocyte adhesion and extravasation, which could contribute to explaining the lymphopenia observed in severe covid-19 patients [23] . endothelial dysfunction increases oxidative stress and systemic inflammation, glycocalyx degradation and inducing a procoagulant and antifibrinolytic state [24] . in some, especially old patients, with covid19 infection together with other persistent comorbidity chronic states, these pathways could induce severe respiratory failure [25] . covid-19 infection enters into the elective targets for viral diseases, which are, more generally, epithelial tissues, lung (influenza virus, coronavirus [26] ), liver (hcv and hcv [27] ) and cervix (hpv [28] ), all of which are strongly sensitive to oxidative stress and damages [29] . ros play a fundamental role in the normal functioning of the immune system and in the induction of proliferation of t cells and immunological defense [30] . oxidative stress represents a key factor in inflammation cell signaling for the regulation of cytokines and growth factors, as well as for immunomodulation and apoptosis [31] . recent observations have drawn attention to the possibility that interactions between ros and the human immunodeficiency virus (hiv) may also play a role in the pathogenesis of many other viruses as well [32] . indeed, the role of oxidative stress has been demonstrated in a number of viral infection diseases [33] , where cell pro-oxidative signaling co-occurred with viral infections [34] . viral infection is generally divided into three stages: • stage i, which consists of virus adhesion, adsorption, entry and invasion of cells; • stage ii, or eclipse phase, during which the cell is forced to replicate multiple copies of virus genome; • stage iii, or maturity and release of virus particles (virions). viruses enter the cell through specific receptors and coreceptors using the phagocytosis mechanism. the virus must then break out of the vesicle by which it was taken up in order to gain access to the cytoplasm [35] . the activation of phagocytes induces the release of pro-oxidant cytokines, such as tumor necrosis factor alpha (tnfa), or interleukin-1 and 6, paralleled with a significant iron uptake by the reticuloendothelial system [36] . in turn, the release of tnfa from activated phagocytes induces different intracellular responses. first, it acts on cell mitochondria inducing a pro-oxidant effect through the inhibition of the site of superoxide production (site ii). second, tnfa induces the release of nuclear transcription factor kappa b(nf-k-b) from the cytoplasmic inhibitor protein ikb, activating at a genomic level the transcription of cellular and/or viral genes. many viruses induce host cell death, by apoptosis or pyroptosis among others [37] , probably to enhance replication and expansion into the entire organism [38] . for example, hiv-1 activates pathways causing cd4 t-cell death in infected hosts due to caspase-1-mediated pyroptosis triggered by abortive viral infection. pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and proinflammatory cytokines, including il-1β, are released. this death pathway relies on the two signature events in hiv infection-cd4 t-cell depletion and chronic inflammation-and creates a pathogenic vicious cycle in which dying cd4 t cells release inflammatory signals inducing enlarged cell death [39] . considering this evidence, antioxidant compounds are able to inhibit immune system cells (lymphocytes) through apoptosis and then release proinflammatory cytokines (il-1, il-6 and tnfa) that are likely to prevent lymphopenia, hypoferremia and, thus lower the viral replication in patients suffering severe viral diseases [40] . antioxidants such as vitamin e [41] are able to prevent the inhibition of the site of superoxide production (site ii), while the nf-kb-induced gene transcription can be inhibited by thiol groups [42] belonging to molecules that strongly interact with the antioxidant system [43, 44] . antioxidant therapy might further be related to the inhibition of virally induced cell death by antioxidants that scavenge peroxides, such as n-acetylcysteine and glutathione peroxidase [45] . it was observed that the antioxidant n-acetylcysteine blocks viral production in monocyte cell lines, which are the major reservoir for hiv in infected patients [46] . the epigallocatechin-3-gallate from green tea blocks hiv entry [47] due to its antioxidant properties. therapeutic treatments to inhibit or reduce virus replication in human cells are unfortunately restricted. known examples are mostly anti-hiv drugs, such as ritonavir, sequinavir, or antiflu, such as lopinavir, abifìgavan, or anti-ebola reagents. they all can have short-term or long-term adverse effects [48] , which makes it necessary to explore new molecular moieties in the perspective of producing new pharmaceutical tools [49] . many antiviral drugs are synthetic organic chemicals or natural derived products, for example, from secondary metabolites of plants [50] . in the emergent "blue" technology era, there is a growing interest in marine-derived antiviral compounds. marine organisms represent a rich source of many antioxidants that are promising for the development of drugs for the prevention and treatment of various chronic and acute human diseases [51] . thus, thousands of compounds from various marine organisms such as algae, bacteria, fungi, marine invertebrates or sponges have been screened and 21 of them have demonstrated antiviral activities [17] . in 2018, fedoreyev et al. [2] reported that an antioxidant "soup", containing echinochrome a (pigment of sea urchins), ascorbic acid (vitamin c) and α-tocopherol (vitamin e) possess in vitro antiviral activity against rna-containing tick-borne encephalitis virus and dna-containing herpes simplex virus type 1 [2] . this study also demonstrated that a synergistic effect of antioxidant molecules can be effective against virus infections. while the research and development of antiviral compounds are mainly focused on macroalgae [52] , the interest in microalgae and cyanobacteria has increased since they are known to produce many antioxidant molecules, which also possess antimicrobial, anticancer and antiviral activities [53] . moreover, cyanobacteria and microalgae in general are promising since the relatively low-compared to higher plants-requirements for growth make them good candidates for the production of antiviral agents at an industrial scale [54] . the compounds mainly capable of antiviral activities comprise sulfated polysaccharides, phenolic compounds, and organic acids [55] . in recent years, it has been shown that marine sulfated polysaccharides possess a wide range of bioactivities, such as anticoagulant, antioxidant, anti-inflammatory, antiviral, antibacterial, antiproliferative, antitumor, anticomplementary and antiadhesive activities [56] . interestingly, the antiviral activity exhibited by these compounds is often related to their immunomodulation and anticancer activities [57] . the double effect, anticancer and antiviral, of these natural compounds is mainly related to their capability to inhibit cell proliferation and to activate ifn signaling pathways that inhibit kidney and liver cancer progression [58] . in general, antiviral compounds extracted from (micro)algae are mainly polysaccharides that have been screened against pathogenic human viruses ( table 1 ). the mechanisms of action of these compounds against viruses are not fully clarified, but the activity seems to be related to their antioxidant power inhibiting the different stages of the viral infection, and interfering with its adhesion, penetration or replication [59] . for example, the sulfated polysaccharide isolated from the cyanobacteria spirulina platensis, named spirulan, has exhibited potent antiviral activity against both the herpes simplex virus type 1 (hsv-1) and the human immunodeficiency virus type 1 (hiv-1) [87] . the sulfated polysaccharides (sps) carrageenans from red algae (rhodophyta) display antiviral effects on several viral agents [60] , and are significantly active against hpv [61] . they predominantly act by inhibiting the binding or the internalization of virus into the host cells [62] . the carrageenan isolated from gigartina skottsbergii exert promising antiviral activities towards diverse strains of hsv-1 and hsv-2 during virus attachment stage [63] and against human rhinovirus (hrv) proliferation by preventing the primary phases of virus replication [64] . a recent in vivo study in mice indicated that low molecular weight carrageenans (3, 5, and 10 kda), as well as acetylated and sulfated derivatives, were active against influenza virus and reduced the hiv activity by depolymerization and sulfation processes [65] . another class of sulfated polysaccharides is represented by galactans, present in the external membranes of red algae [66] . the various structural types of this class of polysaccharides display relevant antiviral activity against several enveloped viruses, such as hsv-1 and hsv-2, denv, hiv-1 and hiv-2, and hepatitis a virus [67] . the galactan sulfate (gs), isolated from the red alga agardhiella tenera, displays an effective control against hiv-1 and hiv-2, blocking the virus adhesion to the cell as well as the attachment of gp120 on cd4+ t cell receptor to hiv-1 gp120 [68] . another sulfated galactan isolated from the red seaweed, schizymenia binderi, presented highly selective antiviral effects against hsv types 1 and 2 by the inhibition of the attachment of virus to host cells [69] . the d,l-galactan hybrid c2s-3, extracted from the marine red alga cryptonemia crenulata, blocks the multiplication of denv-2 in vero cell line [70] . alginates are polysaccharides widely distributed in brown algae (phaeophyceae), which have also been particularly attractive for their antiviral activities [71] . in particular, an alginate named 911 exhibited promising activity against hiv-1 decrementing the activity of reverse transcriptase (rtase), discontinuing the virus adsorption, and immunostimulating the host cells [72] . alternative inhibitory results were also reported against the hepatitis b virus (hbv), where 911 alginate could inhibit the virus replication by suppressing the activity of dna polymerase [73] . furthermore, the sulfated polymannuroguluronate (spmg) is a promising anti-aids drug candidate, inhibiting the robust attachment of hiv-1 gp120 protein with cd4 molecules on the surface of t cells [74] . fucans are high-molecular-weight sulfated polysaccharides, present in the intercellular tissues or mucilaginous matrix of brown algae [75] . beside many bioactivities, such as antiproliferative, antiadhesive properties can protect the cells from viral infections [76] . for instance, the sulfated fucans from the brown seaweeds, dictyota mertensii, lobophora variegata, fucus vesiculosus, and spatoglossum schroederi, could prevent hiv infection via the blocking effect of the activity of reverse transcriptase [77] . this study highlighted the necessity of sulfate and carboxyl groups in the inhibitory viral activity of the polysaccharides. the compound named mc26, a new type of fucose polysaccharide isolated from the marine brown alga, sargassum piluliferum exhibited a strong anti-influenza virus activity [78] . furthermore, the sulfated fucans extracted from the brown seaweed cystoseira indica showed a promising activity against hsv-1 and hsv-2 [79] . it was suggested that these compounds might act against viral infection through the inhibition of virus adsorption [80] . the polysaccharides fucoidan, based on the sulfated l-fucose, possesses various biological activities, among them activities against many rna and dna viruses such as hiv, hsv1-2, dengue virus, and cytomegalovirus [81] . fucoidans exert their antiviral activities by blocking the interaction of viruses with the cells, thus inhibiting viral-induced syncytium formation [82] . this property led to attachment of fucoidan to the f0 protein resulting in a great antiviral potency of fucoidan, e.g., higher than the antiviral drug ribavirin [83] . last but not least, fucoidans also display bioactivity on the immune system at cellular and humoral level by increasing macrophage phagocytosis [84] . the glucan laminaran, one of the most common polysaccharides in brown algae, exhibits a great antiviral activity and low toxicity in vivo [78] . laminaran polysaccharides extracted from brown algae are proficient to prevent the activity of hiv by preventing its adsorption on human-derived lymphocytes and by blocking the ability of hiv reverse transcriptase, thus the virus' proliferation [72] . three polysaccharides extracted from marine microalgae, naviculan from the diatom navicula directa, and two others (named a1 and a2) from the dinoflagellate cochlodinium polykrikoides also displayed antiviral activities against several enveloped viruses, such as hiv-1, hsv-1 or influenza virus type a (ifv-a) [71] . the sulfated polysaccharide p-kg03 extracted from another dinoflagellate gyrodinium impudicum has been also reported active against the encephalomyocarditis rnavirus (emcv) [85] , and against several strains of influenza viruses, with efficiency comparable to some existing drugs [86] . the common characteristic between the above-described examples of antiviral activity from algal polysaccharide is the presence of sulfated groups in their chemical structure [96] . although these compounds might act on stage iii of viral infection, selectively inhibiting reverse transcriptase in the case of hiv, thus hampering production of new viral particles after infection [97] , the inhibitory effect generally might refer to stage i of viral infection. this is a crucial aspect to investigate since the antiviral property starts with the interaction between the molecule and the positive charges of the virus or on the cell surface, preventing penetration of the former into the host cells [98] . indeed, sulfated exopolysaccharides from some marine microalgae have been hypothesized to interfere with stage i of viral infection [99] . therefore, small molecules, such as sulfated polysaccharides, represent a good challenge in antiviral drug discovery studies, since the actual antiviral pharmaceutics are proteins and act at the stage ii of the infection. considering the covid19 disease [100] , this virus is very infective due to the high adhesion capacity on the oral cell surface [101] and for the easy entrance ability through the ace2 receptor on the lung cell surface (stage i of the viral infection) [102] . less investigated, but with a high antioxidant activity, and therefore as potential antiviral, are the polyphenolic compounds: antioxidants produced by marine algae, such as flavonoids, cinnamic acid, benzoic acid, gallic acid, quercetin [91] and phlorotannins, the latter being found in brown macroalgae [92] , or diatoms [93] . phlorotannins are tannin derivatives exhibiting numerous bioactivities, such as antioxidant, anti-inflammatory [94] antibacterial, and antimatrix metallopeptidases (mmp) activities [95] . ahn et al. [93] reported that phloroglucinol derivative 8,8 -bieckol inhibited the activity of recombinant rt and protease of hiv-1 in vitro. another peculiar polyphenol discovered in some diatoms, (haslea sp.) marennine, presented relevant bioactivity and antiviral properties [95] . viral infections are often promoted by oxidative processes, favoring replication in infected cells, induction and inhibition of cell proliferation. antiviral activities of antioxidants acting in the antiviral infection task can be exploited as the sea is a fruitful reservoir of such compounds. many algal sulfated polysaccharides-several of them being exclusively marine-present strong antiviral activities. furthermore, tannins, e.g., phlorotannin-exclusive in brown algae-as well as some phycobiliproteins-exclusive in marine algae-exert antiviral activities. to implement natural antiviral tools, there is a priority of: (i) investigating the antiviral activities and mechanisms of action, and (ii) focusing on microalgae, as fast dividing and easily exploitable organisms. the antiviral activity of various microalgae has been demonstrated, although there is a lack of information on many classes. since microalgae are known to be rich in bioactive molecules-the so-called biofactory cells-and present a high diversity and complementarity of antioxidant compounds, they are the ideal reservoir of a sea-derived antiviral pharmacy. this is a fundamental aspect since synergy between molecules, and combinations of diverse backbones, can be further effective against virus infections, as demonstrated in the development and success of the haart combination therapy for hiv. the promising results reviewed in this communication suggest and urge for investment and advanced research into the development of knowledge on marine antiviral drugs and to develop a pipeline reaching into the biodiversity and chemodiversity of (micro)algae screening to screen them with an antiviral focus. author contributions: all authors have 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blue pigment sulfated seaweed polysaccharides as multifunctional materials in drug delivery applications molecular strategies to inhibit hiv-1 replication cell entry mechanisms of hsv: what we have learned in recent years antimicrobial activities of microalgae: an invited review. in science against microbial pathogens: communicating current research and technological advances; mendez-vilas, a., ed.; formatex microbiology book series coronavirus disease 2019 (covid-19) in italy mechanisms of coronavirus cell entry mediated by the viral spike protein ace2 receptor expression and severe acute respiratory syndrome coronavirus infection depend on differentiation of human airway epithelia acknowledgments: the authors acknowledge the two reviewers for their comments on the previous version of the manuscript. the authors declare no conflict of interest. key: cord-261170-arnwk287 authors: gallimore, w. title: chapter 18 marine metabolites oceans of opportunity date: 2017-12-31 journal: pharmacognosy doi: 10.1016/b978-0-12-802104-0.00018-4 sha: doc_id: 261170 cord_uid: arnwk287 abstract the marine environment provides an array of compounds often with unique molecular architectures boasting an equally wide array of bioactivities including anticancer, antiinflammatory, and antimicrobial activity. typically without the benefit of folklore therapeutic knowledge, marine organisms are collected, extracted, and fractionated to afford compounds that undergo evaluation with in vivo and in vitro assays en route to clinical applications. the pharmaceutical industry has benefited from research into marine metabolites with the development of marine-derived drugs including cytarabine, vidarabine, and ziconotide along with the more recently developed formulation carragelose, an antiviral spray. cosmetic applications incorporating marine extracts include abyssine and refirmar. research with macroinvertebrates, macroalgae, and microorganisms continue in the hope that drugs of the future will be culled from the oceans of the world. while obtaining a consistent and adequate supply of the bioactive compounds remains a challenge to be overcome, synthetic methods are being employed along with the application of biotechnological techniques to ensure that the drugs, when developed, will be in sufficient quantities for distribution to those who are in need. to gain an understanding of the importance of marine natural products chemistry in drug development g to be able to map the process involved in drug development from marine natural products g to gain an appreciation of the range of biological activities associated with compounds isolated from micro-and macroorganisms g to identify the marine-derived drugs which are undergoing clinical evaluation over 75% of the earth's surface is covered by vast expanses of ocean. its inhabitants are diverse with 15 of the 34 phyla occurring exclusively in the oceans with only one phylum (onychophora) being reported as present on land only [1] . the marine environment provides an array of structurally unique and diverse constituents produced by an equally diverse consortium of marine organisms living on our coral reefs and in benthic communities. the marine organisms are highly variable in species, color, and morphology and belong to several phyla including porifera (sponges), ascidiacea (sea squirts), and octacorallia (soft corals). the metabolites of marine origin emanate from a variety of parts of the plants and animals and are thought to be produced as a form of chemical communication, defense, or to ward off potential predators [2à12] (figs. 18.1à18.3). the potential for a range of applications including anticancer, antibacterial, antiviral, antiinflammatory, antimalarial, antituberculosis activity, as well as pharmacological and industrial applications. the classes of compounds manufactured by marine organisms include alkaloids, terpenoids, shikimates, peptides, and polyketides [2à15] . temperature, salinity, ph, and dissolved oxygen concentrations in the water, thereby providing useful information to facilitate environmental studies [20, 21] . caution should always be exercised in the collection of marine species. gloves should be worn in the collection and subsequent handling of specimens. scuba divers should be clad in wet suits to protect against the possible deleterious effects of chemicals being exuded into the water by the organisms being collected. the personal unfortunate experience (author's) of hours of severe discomfort and rashes as a result of collecting the sponge neofibularia nolitangere from a reef in discovery bay, jamaica, provides clear evidence regarding the level of respect which should be accorded to figure 18 .5 student snorkeling to collect marine specimens. marine organisms whose chemistry is yet to be investigated. records are made of the depth, habitat, global positioning system coordinates (latitude and longitude), color, morphology, and associated organisms. an appropriate coding system should be employed to distinguish specimens. where possible, the specimens are photographed in situ as well as by the dockside (figs. 18.7 and 18.8) . a voucher specimen of each organism is usually preserved in 70% aqueous ethanol for the purpose of taxonomic identification. ascidians are usually preserved in seawater containing menthol crystals with more long-term storage in 10% formalin solution [22] . it should be noted that the recollection of organisms has proved to be a challenge in some instances. an ascidian species, e.g., found to be thriving on the mangrove in the summer of one year could all but disappear from the ecological landscape 6 or 12 months later, while a healthy bed of algae may be short-lived if there are dynamic factors involved in their growth. for example, the occasional nutrient runoff or groundwater seepage event could provide the ideal environment for the growth of selected algal species. environmental factors are key in the marine landscape and often provide a source of frustration to the specimen collector. prior to extraction of the collected organism, the specimens may be frozen, air-dried, freeze-dried, or could be retained in the fresh state. the majority of the marine organisms are extracted fresh or frozen while the remaining specimens are lyophilized or dried in air before extraction [22] . in some instances, dried algal species are ground to a powder prior to extraction as described by sansom and coworkers who isolated an antiproliferative bis-prenylated quinone from the alga perithalia capillaris [23] . the extraction of marine organisms may be carried out using a range of organic solvents including hexanes, dichloromethane, acetone, ethyl acetate, as well as more polar solvents such as ethanol and methanol. in many instances, a mixture of polar and medium polarity or nonpolar solvents is utilized in the extraction protocol. for example, the extraction of the madagascar sponge monanchora dianchora was achieved in ch 3 cl:meoh (1:1) to yield two polycyclic guanidine alkaloids [24] . extractions are usually exhaustively performed over several days with at least three aliquots of the solvent being used. the solvent is then removed in vacuo by rotary evaporation. solvent partitioning is another strategy employed in the extraction of the organisms. this involves single one-step or two-step partitioning systems usually involving an aqueous phase portioned with a solvent immiscible with that phase. the kupchan and modified kupchan procedures are often employed in natural products as was described in the isolation of a diterpene from an axinella species [25] . in this procedure, the concentration of the aqueous layer is progressively adjusted to afford three or four different fractions. complex partitioning procedures are also employed, albeit rarely so. simple partitioning has been most commonly employed with kupchan schemes being utilized with less frequency [22] . chromatographic methods of separation include gravity column chromatography, flash column chromatography, and vacuum liquid column chromatography utilizing silica gel as the packing material. with silica gel, the components of the marine extract are separated on the basis of polarity of the compounds. as the polarity of the eluting solvent increases compounds of increasing polarity are eluted from the column with hydrocarbons, e.g., eluting before alcohols. the elution of the components of a column is monitored by using thin layer chromatography (tlc) plates which are spotted to show the sequence of elution of the compounds (figs. 18.9 and 18.10). bonded reverse phase silica is employed in instances where the constituents of the marine extract include polar metabolites. bonded phases include ods (c 18 ), c 8 , cyano, and diol columns. separation of constituents may also be effected using gel permeation chromatography which effects separation of constituents on the basis of the size of the compounds. in this regard, sephadex lh-20 is commonly utilized in marine natural products isolation work [26] . resins such as biobeads, amberlite, xad-2, and xad-4 are also utilized in separating components of relatively high polarity. the use of xad-2 in the separation of antiviral trisulfated triterpene glycosides from the sea cucumber staurocucumis liouvillei is one such example in marine natural products isolation work [27] . the use of hplc employing a reversed phase stationary phase system is commonplace in marine natural products isolation work with c 18 and c 8 semipreparative and preparative columns being used. mplc and recycling hplc techniques are related techniques for purification of a range of metabolites including alkaloids, peptides, and terpenoids. tandem systems such as liquid chromatography-mass spectrometry systems are also employed to assist with dereplication efforts. unusual ms peaks in the profile suggest that novel components are present in the fraction or extract being evaluated. those fractions with unusual constituents may then become the focus of the research efforts. solidphase extraction methods are also employed in separating compounds. the structural identification of compounds isolated from the range of marine sources is facilitated by the use of spectroscopic techniques such as 1d and 2d nuclear magnetic resonance (nmr) spectroscopy and infrared (ir) spectroscopy. x-ray crystallographic techniques are also important in aiding in the determination of the stereochemistry of the compound. the identification of nanogram quantities of a novel compound is becoming increasingly more facile with the use of the cryoprobe, capillary probe, and mans probe [15] . in vitro activities of marine metabolites have been investigated for a diverse range of cell systems including antiinflammatory, antimicrobial, and anticancer activities. crude extracts, fractions from crude extracts, as well as pure compounds are typically evaluated for biological activity. the in vitro biological evaluation of the isolated compound may be performed using cell lines from human subjects or animals. brine shrimp, fish, and sea urchin are among the organisms employed in the evaluation of compounds or extracts for ecological and therapeutic importance (figs. 18.11 and 18.12) . a summary of the biological activity of some of the organisms discussed in this section is presented in preclinical trials are an essential component of the process of evaluation of the therapeutic potential of a compound. these trials often include animal models such as rats, dogs and monkeys. the major sources of biologically relevant compounds have been found to be from sponges, coelenterates, algae, echinoderms, ascidians, molluscs and microorganisms [14] . macroinvertebrates include sponges, ascidians, and soft coral. it has been found that the vast majority (75%) of novel compounds obtained from the marine environment have been sourced from the porifera and coelenterata (cnidaria) phyla [15] . scheme 18.1 shows representative structures of compounds isolated from macroinvertebrates. macroinvertebrates include: 1. sponges 2. ascidians 3. soft coral sponges (porifera) are sedentary, filter feeding metazoans which utilize a single layer of flagellated cells (choanocytes) to pump water current through their bodies in a unidirectional manner. there are over 5000 species of sponges accounting for much of the epifaunal biomass. extracted fresh or freeze-dried, sponge extracts are an important source of biologically active compounds. these isolates exhibit an impressive array of biological activities, some of which are described here. one sponge which has gained a place in history due to the promising biological activity being displayed is halichondria okadai, the producer of halichondrin b, which underwent evaluation as an anticancer agent. okadaic acid, also from h. okadai, exhibited inhibitory activity against phosphatase-1 and phosphatase-2a [28] (fig. 18 .13). agelaspin, an antitumor glycosphingolipid obtained from the marine sponge agelas mauritianus, demonstrated antitumor activity in vivo against murine b16 melanoma. this compound was also found to stimulate the immune system. a derivative of agelaspin, krn-7000, underwent clinical investigations for cancer immunotherapy [28] . more recently, the extracts of another agelas sp., a. nakamurai, contained the compound agelasine d which exhibited high antibacterial activity [29] . the deep water sponge discodermia dissoluta produced discodermolide, a polyhydroxylated lactone which exhibited anticancer activity, as well as immunosuppressive activity. it was found to stabilize microtubules in a manner similar to the drug taxol and underwent evaluation for use in tumors resistant to taxol [30, 31] . dysidea arenaria was found to contain arenastatin a which showed potent activity against kb cell lines (ic 50 5 5 pg/ml) [32] . girolline is a substituted imidazole isolated from the sponge pseudaxinyssa cantharella which functions by inhibiting the termination step in eukaryotic protein synthesis. having entered phase 1 clinical trials, it was withdrawn due to its adverse hypertensive effects seen in treated patients [28] . mycalamides a and b are protein synthesis inhibitors isolated from the new zealand sponge mycale sp. in vivo activity against a59 coronavirus was observed in mice when treated with a 2% mycalamide mixture at a dosage of 0.2 μg/kg daily with 100% survival over a two-week period. pure mycalamide a inhibited the herpes simplex virus 1 and polio virus type 1 at a concentration of 0.005 μg/disk. mycalamide b was found to exhibit more potent antiviral activity and cytotoxicity than mycalamide a [28] . the baculiferins i, j, l, and m from the marine sponge iotrochota baculifera have been found to inhibit human immunodeficiency virus-1 (hiv-1) with ic 50 values between 0.2 and 7.0 μm [33] . jasplakinolide, the first example of a cyclodepsipeptide isolated from a sponge, is a 19-membered macrocyclic depsipeptide from the jaspis sp. exhibiting in vitro antimicrobial activity at a minimum inhibitory concentration of melinacidins and gencidin antibacterial marinospora sp. lynamicins a-e antibacterial 25 μg/ml against candida albicans. with a topical administration of 2% jasplakinolide solution, an effect similar to that of miconazole nitrate was achieved in vivo [28] . discorhabdin r is a novel pyrroloiminoquinone isolated from the southern australian sponge negombata sp. and antarctic latruncula sp. which was found to display antibacterial activity against both gram-positive (staphylococcus aureus and micrococcus luteus) and gram-negative bacteria (serratia marcescens and escherichia coli), respectively [34] . antibacterial activity against a strain of the bacterial parasite plasmodium falciparum was reportedly identified in monanchora arbuscula with the active agents being the batzellidine alkaloids (ic 50 5 0.2à0.9 μm) [35] . an important isolate from a spongia sp. is the polyhydroxylated steroid, agosterol a, which functions by reversing multidrug resistance caused by the overexpression of two kinds of membrane glycoprotein in cancer cells [36] . from the phylum cnidaria the genera sinularia and briareum have proven to be prolific sources of novel compounds. cembranoids, 5,8-epidoxysteroids, sinulaflexiolides, and africanenes have been isolated from sinularia species [1] (fig. 18.14) . examples of other species of soft corals include the taiwanese soft coral cespitularia taeniata which was extracted with ethanol to yield a group of verticillene diterpenoids including cespitulactam k. the compounds were evaluated against human epidermal carcinoma and murine l1210 leukemia cell lines. cespitulactam k exhibited activity against the cancer cell lines (3.7à5.1 μg/ml) and also showed marked antimicrobial activity against m. luteus and cryptococcus neoformans [37] . the methanol extract of the octocoral muricea austera showed in vitro activity against chloroquine-resistant p. falciparum and was found to contain a range of different classes of compounds including tyramine derivatives, steroidal pregnane glycosides, and sesquiterpenoids [38] . cytotoxic dolabellane diterpenes were isolated from the formosan soft coral clavularia inflata var luzoniana and bioactivity against p388 cell lines with ed 50 values between 0.5 and 3.6 μg/ml was observed [39] . tunicates, sea squirts, or ascidians belong to the subphylum of tunicata (urochordata). they are so named because of their cellulose-containing protective tunic surrounding the organism. tunicates attach to a substratum, usually a marine solid surface such as a mangrove root, rocks, jetties, or even algal species (fig. 18.15 ). much like sponges and soft corals, ascidians have also been found to be a good source of bioactive agents. didemnin b, isolated from the tunicate trididemnum solidum, is one such bioactive compound, showing remarkable antiviral and cytotoxic activity. didemnin b demonstrated activity against p388 and l1210 murine leukemia cell lines. it was advanced into preclinical and clinical trials 1 and 2, but had to be withdrawn due to its harsh toxicity [30] . aplidine, formally known as dehydrodidemnin, an isolate from the mediterranean tunicate aplidium albicans, is one such bioactive compound. being structurally related to didemnin b, aplidine was found to be up to 10 3 more active and less toxic than didemnin b. it entered into phase 1 clinical trials in 1999 under investigation for the treatment of solid tumors and non-hodgkin's lymphoma. broad spectrum activity was displayed in vitro and in vivo against leukemia, melanoma, breast, ovarian, colon, and lung (nonsmall cell) cancer. having advanced to phase 2 clinical trials, aplidine affects protein synthesis through gtp-dependent inhibition of elongation factor 1-α [30] . the extract of the palauan ascidian didemnum guttatum afforded the sulfonated serinolipid cyclodidemniserinol trisulfate which exhibits an antiviral effect by inhibiting hiv-1 integrase, an attractive target for antiretroviral chemotherapy [30] . macroalgae belong to three main phyla: rhodophyta (red algae), chlorophyta (green algae), and phaeophyta (brown algae). biological activities identified in extracts and metabolites of algal origin include anticancer, antiobesity, neuroprotective, and antioxidant activity and scheme 18.2 shows chemical structures of representative bioactive compounds isolated from the macroalgae. a wide range of algal species are utilized in fresh or dried forms as food particularly in asian countries where folklore traditions govern their industrial and medicinal usage [40] . macroalgae are the source of agar, carrageenan, and alginate, which are all of importance in the food industry. the range of compounds isolated from algal sources has been variable. representative examples of bioactive constituents from macroalgae are mentioned below. cytotoxic activity has been identified in 8α,11-dihydroxypachydictyol a, a diterpenoid compound from a dictyota sp. collected on bangsaen beach in thailand. antimalarial activity was also found in the diterpene isolated from this extract when the compound was tested with malarial parasites [41] . stypolactone, an isolate from the brown alga stypopodium zonale, was found to exhibit weak cytotoxic activity in vitro when evaluated with a-549 and h-116 cell lines [42] . zonaquinone acetate, obtained from jamaican populations of s. zonale, displayed in vitro activity against breast and colon cancer cell lines [43] . specimens of taonia atomaria produced atomarianones a and b which were reportedly found to be cytotoxic against nsclc-n6 and a-549 cell lines [44] (fig. 18.16) . crude extracts of algal species have been found to exhibit a range of biological activities. for example, aqueous extracts of gracilaria corticata and sargassum oligocystum exhibit bioactivity against cancerous human leukemia cells [45, 46] while a methanol extract of plocamium telfairiae was observed to display bioactivity against ht-29 colon cancer cells [47] . antiinflammatory activity was found in the green alga from which 2-(2,4 0 -dibromophenoxy)-4,6-dibromoanisol was isolated. this activity was identified using a snake toxin-induced mouse limb model [48] . also exhibiting antiinflammatory activity is a mixture of phytosterols obtained from dunaliella tertiolecta. when administered in a sheep model of inflammation-induced cytokine production, an inhibitory effect was observed [49] . polyphenolic extracts from the red alga laurencia undulatea displayed antiinflammatory activity in vivo. these extracts served to inhibit asthmatic reactions in mice sensitized and challenged with ovalbumin which was used to induce murine allergic reactions in test subjects [50] . antiinflamatory agents floridoside and d-isofloridoside from the south korean alga l. undulatea were found to inhibit free radical oxidative stress at ic 50 values between 22 and 43 μm [51] . biologically active compounds have been isolated from the brown seaweed dictyota cervicornis from which was obtained sulfated polysaccharides with powerful anticoagulant activity [52] . antioxidant activity, evaluated using the dpph method, was reported in phenolic isolates of halimeda monile when liver injury was induced in a rat model. the phenolic fraction was administered over a 20-day period and led to protective effects against chemicals harmful to the liver [53] . with ic 50 values between 0.5 and 2.9 μm, potent antimalarial activity against the human malarial parasite p. falciparum was identified in new macrolides bromophycolides j, m, n, o, p, and q from the red algae callophycus serratus [54] collected in fiji. the marine alga halimeda tuna was studied by koehn and coworkers, leading to the isolation of halitunal, a diterpene displaying in vitro antiviral activity against murine coronavirus a59 [55] . ecologically important roles are played by some compounds from alga sources. for example, halimedatrial, a diterpene isolated from halimeda lamouroux, exhibited toxicity toward reef fishes and appeared to be a feeding deterrent. antimicrobial activity was also reported from this compound [56] . almost 20% of all bioactive marine compounds currently being studied are obtained from marine microorganisms [15] . these microbes are found in swabs from the surfaces of marine plants and animals, suspended in the water from geothermal vents and deep water environments, or on sediment surfaces. they thrive in a variety of environments including locales characterized by high pressures of up to 600 atmospheres, high temperatures, and high salinities. efforts at culturing some of the microorganisms have met with varying degrees of success. the ability to propagate these microorganisms in an economically feasible way will be of great significance as potent bioactive metabolites are discovered [57] (figs. 18.17à18.19 ). marine microorganisms are found 1. on the surface of marine plants and animals 2. suspended in water 3. on sediment surfaces historically, terrestrial microbes have been a potent source of pharmaceutical agents with the seminal discovery of penicillin. the discovery of new antibacterial agents is a serious priority because of the development of potent resistance to current antibiotics on the market. marine bacteria produce a wide variety of secondary metabolites for the purpose of defending themselves against other microbes. scheme 18.3 shows structures of representative compounds from microorganisms associated with marine specimens. marine bacteria which produce compounds of biological significance include pseudoalteromonas species which was found to produce 3,3 0 , 5,5 0 -tetrabromo-2,2 0 -diphenyl diol, an inhibitor of methicillin-resistant s. aureus. the class of 4-methoxypyrrole-containing compounds, the tambjamines, isolated from p. tunicata, was found to be active antifungal, immunosuppressive, and antimicrobial agents. biologically active compounds from marine bacteria also include streptomyces species from sediment and fish gut from which anticancer (e.g., halichomycin and δ-indomycinone) and antibacterial agents (e.g., phenazines) have been obtained [58à60]. vibrio species obtained from sponge specimens have produced phenolic and trisindole compounds with antibacterial activity [61, 62] . a micromonospora sp. obtained from a soft coral produced thiocoraline, a compound exhibiting anticancer activity [63] . marine fungi have also been known to produce compounds with a range of bioactivities including antiviral, antifungal, enzyme inhibition, and anticancer and antibacterial activities. the isolation and cultivation of fungi from the marine environment is of critical importance for propagation of the microbes from which biologically relevant compounds may be obtained. protocols have been established for this work [64] . fungal species which have produced antibacterial compounds include corallospora pulchella isolated from sand. this species produced melinacidins and gencidin [65] . anticancer activity has been reported from metabolites of aspergillus sp. (including the aspergillamides and fumiquinazolines) and penicillium sp. sourced from a marine alga which was found to contain pentostatins and communesins among other compounds [66, 67] . antiviral activity, attributable to the presence of halovirs, was identified in a scytalidium sp. collected from a seagrass species. potent antiviral activity against h. simplex virus (type 1) was observed and may be acting by binding directly to the virus [68] . actinomycetes have been the source of a wide range of antimicrobial agents, the most common of which include tetracycline and streptomycin. other bioactive compounds originating from actinomycetes include antitumor and antimicrobial agents. a marinospora sp. produced a group of bisindole pyrroles, lynamicins aàe, which exhibited biological activity against gram-positive and gram-negative species. importantly, activity was also shown against drug-resistant pathogens including methicillin-resistant s. aureus [69] . anticancer activity against lung, colon, and breast cancer cell lines was exhibited by isolates from the fermentation of a streptomyces sp. (mbg-04-17-069). tartrolon d was found to be the bioactive agent [70] . microalgae are found in seven phyla. these include chlorophyta, phaeophyta, rhodophyta, crystophyta, cryptophyta, eugelophyta, and pyrrhophyta. the blue-green algae, cyanophyta, are cyanobacteria which have been found to share characteristics with eukaryotic algae. these microalgae produce compounds with a high degree of structural diversity and species, such as lyngbya majuscula, have produced a vast array of biologically active compounds [71] . curacin a, e.g., isolated by gerwick and coworkers in 1994 [72] , was found to function by disturbing microtubule assembly, thereby functioning as a lead compound in chemotherapy. microcystis aeruginosa is the source of potent protein phosphatase-1 and phosphatase-2a inhibitors identified in microcystins [73] . other microalgal species under examination include dinoflagellates which produce an array of bioactive toxins including saxitoxin and maitotoxin which function by blocking or activating sodium/calcium channels. challenges exist with respect to the culturing of these organisms due to relatively low proliferation rates and the large quantities of culture required to obtain small amounts of bioactive compounds. diatoms, microscopic unicellular colonial algae, grow at a faster rate and are amenable to culturing but few bioactive metabolites have been identified from these microalgae [28] . some marine compounds sourced from microbes are of clinical significance, undergoing evaluation as potential pharmaceutical agents. the marine-derived drug pipeline, almost nonexistent in decades gone by, now has a range of candidates at various stages of development as shown in table 18 drugs in phase three clinical trials include tetrodotoxin, a guanidinium alkaloid under the trademark name tectin obtained from the pufferfish [34] . affecting the sodium channels, this drug is being investigated for the treatment of chronic pains (scheme 18.5). a depsipeptide from a tunicate, plitidepsin, is being tested by pharmamar in the treatment of a variety of cancers, namely leukemia, multiple myeloma, and lymphoma. another drug under evaluation by pharmamar for cytotoxic activity is zalypsis (pm00104) sourced from a mollusc which targets the dna-binding capacity of diseased uterine, lymphoma, cervical, and endometrial cancer cells. the alkaloid-derived compound pm01183 is another drug candidate from pharmamar being evaluated for its efficacy against a range of cancers including ovarian, breast, lung, acute leukemia, and endometrial cancer [74, 75] . bryostatin i, from the bryozoan bugula neritina has been involved in a battery of clinical trials being investigated for its potency against cancer. it is currently under phase i evaluation as a treatment for alzheimer's [74] . in the early years, the challenge associated with the supply of the drug was underscored by the fact that, in order to obtain 18 g of a cgmp quality bryostatin i, 13 tonnes of b. neritina had to be collected in californian waters [13, 76] . the gene cluster of the uncultivated microbial symbiont of b. neritina, candidatus endobugula sertula has been successfully identified, thereby opening the potential for the supply of the compounds [77] . kahalalide f, a cyclic depsipeptide, was found in the mollusc elysia rufescens as well as the green algae bryopsis sp. on which it feeds. this compound is currently in phase i/ii trials as a treatment against prostate cancer [74] (fig. 18.20) . dmxba [(3-(2,4-dimethylxybenzylidene)]-anabaseine is a derivative of anabeseine, an alkaloid found in marine worms. found to improve cognition in animal models, dmxba and other related compounds have demonstrated neuroprotective activity in both in vitro and in vivo screens. thought to have an effect on macrophage 7 receptors, antiinflamatory activity was also observed in animal models. phase i evaluation of healthy males and schizophrenics have shown that dmxba has led to marked improvements in cognitive function [74] . there are several marine compounds sourced from microbes which are of clinical significance. clinical trials are being conducted on plinabulin (npi-2358), a vascular disrupting agent obtained from a marine fungal extract with potential for activity against multidrug resistant tumor cells. marizomib (salinosporamide a, npi-0052), an isolate from a marine bacterium salinospora tropica, is a novel proteasome inhibitor which is currently under investigation for its efficacy against solid tumor models. the compound exhibits low cytotoxicity to normal cells and has significant potential for oral and intravenous administration [74] . the ultimate goal of many marine natural products and synthetic chemists is that the isolated or synthesized molecule possesses therapeutic applications. there are several food and drug association (fda)-approved drugs of marine origin obtained from sponges, a fish, a cone snail, a mollusc, and cyanobacterium species, while yondelis (trabectidin) obtained from the ascidian ecteinascidia turbinata, has been approved in the european union. the antitumor effects of aqueous ethanol extracts of e. turbinata were observed from 1969. in vitro trials had been carried out on a 60 human cancer cell panel by the company developing the drug, pharmamar, and the national cancer institute. aquaculture of the ascidian proved to be the initial strategy used to obtain sufficient quantities for evaluation of the efficacy of the compound. semisynthetic procedures involving the fermentation of pseudomonas florescens are now currently employed in the pharmaceutical preparation of the drug which is sold in over 80 countries, including south korea and russia, under the trade name yondelis. yondelis is also used in patients with relapsed platinum-sensitive ovarian cancer. this drug is currently under evaluation in phase ii for breast, prostate, lung, and pediatric cancers. the sponge tethya crypta (cryptotethia crypta) was the original source from which the drug cytarabine was developed. cytarabine is a synthetic analogue of the nucleoside which was originally isolated from the sponge. sold under the trade name cytosar-u, this cytotoxic agent inhibits deoxyribonucleic acid (dna) polymerase and dna synthesis. acute lymphocytic leukemia, non-hodgkin's lymphoma, and acute myelocytic leukemia are among the conditions being treated by this drug approved by the fda in 1969 [74] . produced by fermentation of streptomyces griseus, cytarabine has limited bioavailability but improvements in the delivery system have been made [78] . a slow-release liposomal form of cytarabine (depo cyle) has been approved in the united states and europe for the prolonged administration/exposure in cerebrospinal fluid. a related drug, vidarabine (vira-a), was developed from spongouridine and found use as an antiviral treatment for epithelial and superficial keratitis caused by the h. simplex virus types 1 and 2. viral dna polymerase and dna synthesis of herpes are inhibited by this drug which was discontinued over 10 years ago. this drug is still in use in europe for ophthalmological challenges. prialt (ziconotide) was obtained from a peptide ω-conotoxin mviia isolated from the cone snail conus magus. with a unique mode of action, this drug acts by reversibly blocking n-type calcium channels in some specific nerves in superficial layers of the spinal cord. this drug is used for the management of severe and chronic pains in patients suffering from cancer and acquired immunodeficiency syndrome who are unable to use or are unresponsive to other drugs such as morphine. ziconotide had to be synthesized using solid-phase peptide synthesis due to the insufficient quantities supplied by the cone snail, c. magus [79] . the blockage of the spinal cord induced by this drug prevents the release of neurotransmitters responsible for pain from specific neurons. related conus peptides are undergoing evaluation in human clinical trials [80] . brentuximab vedotin (sgn-35) is being marketed under the trade name adcetris by seattle genetics and has gained repute for the treatment of hodgkin and systemic anaplastic large cell lymphoma [81] . this drug is an analogue of dolastatin 10, a compound isolated from the sea hare dolobella auricularia, which was later found to be produced by diet-associated cyanobacteria symploca hydnoides and l. majuscula. preliminary phase i and ii clinical trials of dolastatin 10 and a related analogue were largely unsuccessful. antibody-drug conjugates function by selectively delivering the drug to the cancer cell by linking the dolastatin 10, e.g., to an antibody that targets a cell membrane protein on the surface of hodgkin's lymphoma cells. this technology has proven to be a seminal development. omega-3 fatty acids from fish oils are being marketed under the trade name lovaza by glaxosmithkline. used in the treatment of hypotriglyceridemia, the drug controls ethyl esters of eicosapentaenoic acid and docosahexaenoic acid and functions by lowering triglyceride levels. [81] . eribulin mesylate (e 7389), with the trade name halaven was formulated from the macrolide halichondrin b sourced from the sponge h. okadai. studies related to the anticancer activity of simpler analogues of halichondrin b showed that the efficiency is retained leading to the development of eribulin mesylate which is more water soluble than the parent macrolide. now approved for use, potent and irreversible inhibition in cancer cells medicated by this drug resulted in the death of the cells by apoptosis. in the absence of tubulin, cell growth grinds to a halt. related compounds are currently being evaluated in phase ii trials [81] . one of the more recent formulations on the market is carragelose, an antiviral nasal spray which functions by creating a physical antiviral barrier in the nasal cavity. the company marinomed biotechnologie gmbh, utilized iotacarrageenan, sulfated polysaccharides found in the rhodophyceae seaweed as well as other seaweeds. the product is effective against the early symptoms of the common cold [81] . it should be noted that, in addition to the pharmaceutical applications of marine-sourced therapies, a range of cosmetic applications also exist and are thriving industries. the foray into cosmetic applications was led by estee lauder with the antiaging skin care remedy resilience which contains an extract from the caribbean sea whip pseudopterogorgia elisabethae. the active antiinflammatory and analgesic agents are the pseudopterosins, tricyclic diterpene glycosides, which have been found to inhibit pla2 and 5-lipoxygenase. derivatives of the pseudopterosins underwent phase i and ii trials to examine wound healing efficiency but the lipophilic and insoluble nature of the compounds have served to limit its potential as an effective drug. compounds from this group of tricyclic diterpene glycosides also underwent preclinical evaluation as antiinflammatory drugs [81] . abyssine is marketed as a product used to soothe and reduce irritation in skin sensitive to ultraviolet b light as well as chemical and mechanical attack. it consists of an extract from an alteromonas species and contains a high molecular weight polymer with two different oligosaccharides (exopolysaccharide), while seacode represents another exopolysaccharide which occurs as a mixture of extracellular glycoproteins and other glucidic exopolymers produced by fermentation of a pseudoalteromonas sp. this product has been found to improve skin roughness after up to four weeks of administration. refirmar, a recent product to be introduced, was obtained from an intracellular extract from a fermentation of a new pseudoalteromonas sp. isolated from a deep (2300 m) hydrothermal vent in portugal's exclusive economic zone, extraction of the cultured biomass afforded a mixture of macromolecules which inhibit muscle contraction. the hydrating and antiaging potential of the product has been evaluated in vivo and in topically applied formulations [81] . the area of marine natural products chemistry has clearly developed leaps and bounds as evidenced by the relatively large number of marine-derived drugs undergoing evaluation as potential therapeutic agents. buoyed by the potential for the development of natural products from the sea, research work continues to advance with the discovery of new bioactive compounds and new applications for previously isolated molecules [2à15]. the supply issue, however, remains one of critical importance as it relates to the development of drugs from a marine organism. for example, (1) spongistatin 1 has been reported to be highly cytotoxic. it has been deemed to be the most active of all natural and synthetic compounds investigated by the national institute of cancer (usa). three tonnes of the sponge yielded 0.8 mg of the compound. another collection and processing of 400 kg of the sponge afforded 10 mg of the compound. this isolation work facilitated structure elucidation work. the ic 50 value for this compound was evaluated at 10 26 m in colon cancer cells and 10 212 m for breast cancer cell lines [82] . synthetic approaches to the compound have been presented by research groups including petit and coworkers [83, 84] . total synthesis of biologically active marine compounds is often fraught with its attendant challenges due to the length of multistep synthetic procedures and the general complexity of the structural motifs which must take into account stereochemical considerations. propagation through mariculture and aquaculture are also being studied to determine the viability of using these approaches to deal with the challenges associated with procuring sufficient quantities for clinical trials and subsequent formulation into drugs [85] . the timeline from discovering the drug, leading to the entry into the market typically spans a 20-to 30-year period during which time the capital injection is considerable, often necessitating support from the large pharmaceutical entities which are sometimes hesitant about making investments which may not yield significant financial rewards [86] . the caribbean region, being an important source of marine species with which much research work has been carried out, is not likely to become the recipient of the potential benefits to be derived from the development unless more research work in this area is undertaken in the region with support from the appropriate collaborators. in the future, it is expected that new strategies will be employed to ensure the supply of large quantities of the target compounds. these include optimization or fermentation techniques for propagation of microbes, including mixed fermentation methods. biotechnological approaches are likely to include whole genome sequencing, genome mining, genetic engineering, chemoenzymatic synthesis, and in vitro enzymatic synthesis in the hope that new therapeutic drugs will come from our seas [87] . 1. if you were required to evaluate an extract for its potential as a drug, what approach would you adopt? 2. silica gel chromatography is essential for the purification of organic compounds. identify three methods of chromatography. 3. design a form which could be used to document information when collecting a specimen. trends in the discovery of new marine natural products from invertebrates over the last two decades à where and what are we bioprospecting? marine natural products: metabolites of marine algae and herbivorous marine molluscs marine natural products: metabolites of marine invertebrates marine natural products marine natural products marine natural products marine natural products marine natural products marine natural products marine natural products marine natural products marine natural products drugs and cosmetics from the sea marine natural products and their potential applications as anti-infective agents biogeography of sponge chemical ecology: comparisons of tropical and temperate defenses temperature and spatiotemporal variability of salicylihalamide a in the sponge haliclona sp sources of secondary metabolite variation in dysidea avara (porifera: demospongiae): the importance of having good neighbors chemical mediation of interactions among marine organisms marine advanced technology education-marinetech.org. date accessed a survey of deep-water coral and sponge habitats along the west coast of the us using a remotely operated vehicle. noaa technical memorandum nos nccos 138 isolation of marine natural products an antiproliferative bis-prenylated quinone from the new zealand brown alga perithalia capillaris ptilomycalin d, a polycyclic guanidine alkaloid from the marine sponge monanchora dianchora a new cycloamphilectene metabolite from the vanuatu sponge axinella sp bastadin 20 and bastadin o-sulfate esters from ianthella basta: novel modulators of the ry 1 r fkbp12 receptor complex two new cytotoxic and virucidal trisulfated triterpene glycosides from the antarctic sea cucumber staurocucumis liouvillei drugs from the sea from anti-fouling to biofilm inhibition: new cytotoxic secondary metabolites from two indonesian agelas sponges marine natural products and related compounds in clinical and advanced pre-clinical trials discodermolide, a new bioactive polyhydroxylated lactone from discodermia dissolute arenastatin a, a potent cytotoxic depsipeptide from the okinawan marine sponge dysidea arenaria baculiferins aào, o-sulfated pyrrole alkaloids with anti-hiv-1 activity, from the chinese marine sponge iotrochota baculifera marine pharmocolgy in 2000: marine compounds with antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiplatelet, antitubercolosis, and antiviral activities; affecting the cardiovascular, immune, and nervous systems and other miscellaneous mechanisms of action bioactive guanidine alkaloids from two caribbean marine sponges agosterol a, a novel polyhydroxylated sterol acetate reversing multidrug resistance from a marine sponge of spongia sp nitrogen-containing verticillene diterpenoids from the taiwanese soft coral cespitularia taeniata antiplasmodial metabolites isolated from the marine octocoral muricea austera cytotoxic constituents from the formosan soft coral clavularia inflata var. luzoniana a guide to the common edible and medicinal sea plants of the pacific islands novel diterpenes with cytotoxic, anti-malarial and anti-tuberculosis activities from a brown alga dictyota sp an interesting diterpenoid from the brown alga stypopodium zonale antiproliferative activity and absolute configuration of zonaquinone acetate from the jamaican alga stypopodium zonale atomarianones a and b: two cytotoxic meroditerpenes from the brown alga taonia atomaria in vitro antitumor activity of gracilaria corticata (a red alga) against jurkat and molt-4 human cancer cell lines anticancer activity of sargassum oligocystum water extract against human cancer cell lines methanolic extracts of plocamium telfairiae induce cytotoxicity and caspase-dependent apoptosis in ht-29 human colon carcinoma cells biological importance of marine algae a mixture of phytosterols from dunaliella tertiolecta affects proliferation of peripheral blood mononuclear cells and cytokine production in sheep anti-asthmatic effect of marine red alga (laurencia undulata) polyphenolic extracts in a murine model of asthma inhibitors of oxidation and matrix metalloproteinases, floridoside, and d-isofloridoside from marine red alga laurencia undulata biological activities of sulfated polysaccharides from tropical seaweeds free phenolic acids from the seaweed halimeda monile with antioxidant effect protecting against liver injury antimalarial bromophycolides jàq from the fijian red alga callophycus serratus halitunal, an unusual diterpene aldehyde from the marine alga halimeda tuna isolation of halimedatrial: chemical defense adaptation in the calcareous reef-building alga halimeda screening for new metabolites from marine microorganisms δ-indomycinone: a new member of pluramycin class of antibiotics isolated from marine streptomyces sp rare phenazine l-quinovose esters from a marine actinomycete a novel antimicrobial substance from a strain of the bacterium vibrio sp marine natural products. 34. trisindoline, a new antibiotic indole trimer, produced by a bacterium of vibrio sp. separated from the marine sponge hyrtios altum thiocoraline, a new dipsipeptide with antitumor activity produced by a marine micromonospora. 1. taxonomy, fermentation, isolation, and biological activities methods for isolation of marine-derived endophytic fungi and their bioactive secondary products corollospora pulchella, a marine fungus producing antibiotics, melinachidins iii, iv and gancidin w new cytotoxic sequiterpenoid nitrobenzoyl esters from a marine isolate of the fungus aspergillus halovirs a-e, new antiviral agents from a marine-derived fungus of the genus scytalidium lynamicins a-e, chlorinated bisindole pyrrole antibiotics from a novel marine actinomycete tartrolon d, a cytotoxic macrodiolide from the marine-derived actinomycete streptomyces sp. mdg-04-17-069 continuing studies on the cyanobacterium lyngbya sp.: isolation and structure determination of 15-norlyngbyapeptin a and lyngbyabellin d structure of curacin a, a novel antimitotic, antiproliferative, and brine shrimp toxic natural products from the marine cyanobacterium lyngbya majuscula structure and biosynthesis of toxins from blue-green algae (cyanobacteria) the odyssey of marine pharmaceuticals: a current pipeline perspective the bryostatins identification of the putative bryostatin polyketide synthase gene cluster from "candidatus endobugula sertula", the uncultivated microbial symbiont of the marine bryozoan bugula neritina development of cytarabine prodrugs and delivery systems for leukemia treatment industrial natural product chemistry for drug discovery and development conus peptides: biodiversity-based discovery and exogenomics marketed marine natural products in the pharmaceutical and cosmeceutical industries: tips for success marine natural products: a way to new drugs towards a more step-economical and scalable synthesis of spongistatin 1 to facilitate cancer drug development efforts antineoplastic agents. 257 isolation and structure of spongistatin 1 aquaculture of three phyla of marine invertebrates to yield bioactive metabolites: process development and economics mariculture trials with mediterranean sponge species. the exploitation of an old natural resource with sustainable and novel methods marine natural products: a new wave of drugs? key: cord-252108-04xr5xdl authors: havrylyuk, dmytro; zimenkovsky, borys; vasylenko, olexandr; day, craig w.; smee, donald f.; grellier, philippe; lesyk, roman title: synthesis and biological activity evaluation of 5-pyrazoline substituted 4-thiazolidinones date: 2013-06-06 journal: eur j med chem doi: 10.1016/j.ejmech.2013.05.044 sha: doc_id: 252108 cord_uid: 04xr5xdl a series of novel 5-pyrazoline substituted 4-thiazolidinones have been synthesized. target compounds were evaluated for their anticancer activity in vitro within dtp nci protocol. among the tested compounds, the derivatives 4d and 4f were found to be the most active, which demonstrated certain sensitivity profile toward the leukemia subpanel cell lines with gi(50) value ranges of 2.12–4.58 μm (4d) and 1.64–3.20 μm (4f). the screening of antitrypanosomal and antiviral activities of 5-(3-naphthalen-2-yl-5-aryl-4,5-dihydropyrazol-1-yl)-thiazolidine-2,4-diones was carried out with the promising influence of the mentioned compounds on trypanosoma brucei, but minimal effect on sars coronavirus and influenza types a and b viruses. the non-condensed heterocyclic systems with thiazolidinone [1] and pyrazoline [2, 3] moieties have emerged as powerful scaffolds in drug design. among diazole-substituted 4-thiazolidinones highly active anticancer agents have been identified including inhibitors of necroptosis [4] , tumor necrosis factor a [5] and tyrosine phosphatase [6] . our previous study, based on a hybrid pharmacophore approach, allowed to establish a number of patterns in the structureeactivity relationship (sar) context for 4-thiazolidinones with a pyrazoline fragment in 2, 3 and 4 positions of the thiazolidone cycle, which possessed antitumor activity [7, 8] . on the other hand, thiazolidinones and pyrazolines have occupied a unique position in the design and synthesis of novel biologically active agents that exert trypanocidal activity [9e13]. the 2-thioxo-4thiazolidinone-3-acetic acid derivatives were identified as inhibitors of trypanosoma brucei dolicholphosphate mannose synthase [11] . the 2-hydrazolyl-4-thiazolidinone-5-carboxylic acid derivatives have shown promising activity on the cruzipain protease [12] . the most promising compound in series of aryl-4-oxothiazolylhydrazones was shown to be very active at non-cytotoxic concentrations in in vitro assays against trypanosoma cruzi cell cultures and exhibited potency comparable with the reference compounds (ic 50 (y strain) ¼ 0.3 mm) [9] . among pyrazoline derivatives, some novel compounds have been identified as inhibitors of the trypanosomal cysteine protease cruzain with ic 50 of 40e230 nm [13] . the antiviral activity of heteryl substituted 4-thiazolidinones is promising. among thiazoleethiazolidine conjugates [14] and noncondensed derivatives with thiazolidinone and pyridine [15e17] or pyrimidine [18e20] cycles, anti-hiv agents were identified. in addition, this group of compounds was active against hepatitis c virus [21] , tobacco mosaic virus [22] and vesicular stomatitis virus [23] . previously we also demonstrated the efficiency of certain pyrazolineethiazolidinone conjugates on influenza viruses and sars coronavirus [24] . the present work is an extension of our ongoing efforts toward developing promising biologically active agents using a hybrid pharmacophore approach. we made the design (fig. 1 ) and synthesized hybrid compounds by linking the main structural unit of the 4-thiazolidinone ring system with the pyrazoline, and examined their antitumor, trypanocidal and antiviral activities in vitro. we have found two compounds from 5-pyrazoline substituted 4-thiazolidinones, which possessed a commensurate antitumor activity compared to the pyrazolineethiazolidinone analogous compounds reported previously [7, 8] and evaluated anti-trypanosomal activity and antiviral activity of the synthesized compounds. the general methods for synthesis of target thiazolidinonee pyrazoline conjugates are depicted in schemes 1 and 2. the starting 3,5-diaryl-4,5-dihydropyrazoles synthesized using known methods from appropriate chalcones [25] easily reacted with 5-bromothiazolidine-2,4-dione [26] yielding 5-(3-naphthalen-2-yl-5-aryl-4,5-dihydropyrazol-1-yl)-thiazolidine-2,4-dione 1a and 1b. it is known that chemical modification of the n3 position of thiazolidinone cycle has an essential influence on the antitumor activity [27, 28] . relying on these observations we utilized potassium salt of 5-(3-naphthalen-2-yl-5-aryl-4,5-dihydropyrazol-1-yl)-thiazolidine-2,4-dione, generated in situ, in the reactions with 2-chloro-n-arylacetamides. following the mentioned reaction the new n3substituted non-condensed thiazolidinoneepyrazoline conjugates 2ae2c were synthesized. based on the mannich reaction of 1a and 1b with secondary amines the thiazolidinone analogs 3ae3g were obtained (scheme 1). aiming at the detailed elaboration of sar, especially the influence of the linking group of thiazolidinoneepyrazoline conjugates on the anticancer activity, 5-[2-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-2oxoethylidene]-thiazolidine-2,4-diones (4ae4f) were synthesized by the method, described previously [29] . reaction of 3,5-diaryl-4,5-dihydropyrazoles with (2,4-dioxothiazolidine-5-ylidene)-acetyl chloride [27] afforded in excellent yield and purity the compounds 4ae4f. following the reaction of generated in situ potassium salts of 4b and 4e with 2-chloro-n-arylacetamides the group of n3substituted 4-thiazolidinones 5ae5e were synthesized (scheme 2). the data characterization of synthesized novel heterocyclic substituted thiazolidones are presented in experimental part. analytical and spectral data ( 1 h nmr, 13 c nmr) confirmed the structure of the synthesized compounds. protons ch 2 ech of pyrazoline fragment in the 1 h nmr spectra of synthesized compounds showed characteristic patterns of an amx system. the proton (ch) of thiazolidinone core of 1ae1b, 2ae2c and 3ae3g showed the broad singlet at d w5.59e5.99 and the protons of the methylene group (ch 2 co) of 2ae2c and 5ae5e appeared as a broad singlet at d w4.44e4.49 ppm. in the 1 h nmr spectra of the 1ae1b and 4ae4f nh proton of thiazolidinone cycle the broad singlet at dw12.20e12.72 was found. synthesized derivatives 1a, 1b, 2a, 3ae3d, 3f, 4a, 4d, 4e, 4f and 5d were selected by national cancer institute (nci, bethesda usa) developmental therapeutic program (dtp) and evaluated at the concentration of 10 à5 m toward a panel of approximately sixty cancer cell lines (http://dtp.nci.nih.gov). the human tumor cell lines were derived from nine different cancer types: leukemia, melanoma, lung, colon, central nervous system, ovarian, renal, prostate and breast cancers. primary anticancer assays were performed according to the nci protocol as described elsewhere [30e33]. the compounds were added at a single concentration and the cell cultures were incubated for 48 h. the end point determinations were made with a protein binding dye, sulforhodamine b (srb). the results for each compound are reported as the percent growth (gp%) of treated cells when compared to untreated control cells ( table 1 ). the range of percent growth shows the lowest and the highest percent growth found among the different cancer cell lines. the most active compounds 4d and 4f were found to be effective against 12 and 18 cell lines, respectively, compound 4a was found to be moderately effective against few cell lines, while the other compounds (1a, 1b, 2a, 3ae3d, 3f, 4e, 5d) did not show any activity (table 1) . finally, compounds 4d and 4f were selected for an advanced assay against a panel of approximately sixty tumor cell lines at 10fold dilutions of five concentrations (100 mm, 10 mm, 1 mm, 0.1 mm and 0.01 mm) [30e33] . the percentage of growth was evaluated spectrophotometrically versus controls not treated with test agents after 48-h exposure and using srb protein assay to estimate cell viability or growth. doseeresponse parameters were calculated for each cell line: gi 50 e molar concentration of the compound that inhibits 50% net cell growth; and tgi e molar concentration of the compound leading to the total inhibition. furthermore, a mean graph midpoints (mg_mid) were calculated for each of the parameters, giving an average activity parameter over all cell lines for the tested compound. for the mg_mid calculation, insensitive cell lines were included with the highest concentration tested ( table 2 ). the tested compounds showed inhibition activity (gi 50 < 10 mm) against 47 from 55 (4d) and 56 from 59 (4f) human tumor cells with average gi 50 /tgi values of 7.02 mm/38.07 mm (4d) and 4.38 mm/ 50.99 mm (4f) ( table 2) . with regard to the sensitivity against some individual cell lines among several subpanel, the compounds 4d and 4f demonstrated a certain sensitivity profile toward the leukemia subpanel tumor cell lines with gi 50 values range of 2.12e4.58 mm (4d) and 1.64e3.20 mm (4f) ( table 3 ). the sar study revealed that: (1) the level of antitumor activity of active thiazolidinones with pyrazoline fragment in 5 position (4d and 4f) is compatible with effectivity levels of heteryl substituted thiazolidones, described previously [34e42]; (2) conjugation of pyrazoline and thiazolidinone cycles using oxomethylidene linking group (4f) allowed us to increase the activity, in comparison with the structurally related conjugate representative 5-(3-naphthalen-2-yl-5-aryl-4,5-dihydropyrazol-1-yl)-thiazolidine-2,4-dione 1b; (3) introduction of the substituents in 3n-position of thiazolidine fragment did not have significant influence on the antitumor activity. nci's compare algorithm [30e33] allows to assume biochemical mechanisms of action of the novel compounds on the basis of their in vitro activity profiles when comparing with those of standard agents. we performed compare computations for the compounds 4d and 4f against the nci "standard agents" database at the gi 50 and tgi levels (table 4 ). however, obtained pearson correlation coefficients (pcc) did not allow to distinguish cytotoxicity mechanism of tested compounds with high probability. the compound 4d showed the highest correlation at the gi 50 level with dihydroorotate dehydrogenase inhibitor brequinar (pcc ¼ 0.651) and compound 4f e with maytansine (rna/dna antimetabolite, pcc ¼ 0.636). antiviral activity of 1a, 1b, 2ae2c, 3d and 3e was determined against sars coronavirus (sars cov) and influenza types a and b viruses (flu a, flu b). the obtained results are summarized in table 5 . although antiviral activity was evident, virus inhibition occurred at or near the cytotoxic concentration. the compounds showed insignificant activities against the four strains of influenza virus with the range levels of selectivity index from 1.0 to 2.1. compound 2a had moderate activity against the duck strain of influenza a with a 50% effective concentration (ec 50 ) of 21.78 mm and selective index (si) of >16.3; but did not have significant activity against other influenza strains. the majority of the compounds showed no activity against sars cov. the positive control compounds ribavirin, oseltamivir carboxylate, and m128533 were active as expected in the assays. the compounds 1a, 2b and 2c were selected in advanced in vitro assay against trypanosoma brucei brucei (tbb) and trypanosoma brucei gambiense (tbg). the doseeresponse curves with drug concentrations ranging from 10 mg/ml to 0.625 mg/ml are depicted on the results showed a moderated activity of compounds (table 6) on both parasite strains, namely ic 50 (tbb) ¼ 5.43e13.87 mm and ic 50 (tbg) ¼ 2.53e6.66 mm. in the present paper new 4-thiazolidinone based conjugates with pyrazoline moiety at 5 position are described. antitumor activity assay of thirteen synthesized compounds allowed us to identify highly active thiazolidinoneepyrazoline hybrids 4d and 4f, which demonstrated certain sensitivity profile toward the leukemia subpanel tumor cell lines with gi 50 values range of 2.12e4.58 mm (4d) the starting 3,5-diaryl-4,5-dihydro-1h-pyrazole [25] , 5-bromothiazolidine-2,4-dione [26] , and (2,4-dioxothiazolidine-5-ylidene)-acetyl chloride [27] were obtained according to the table 1 anticancer screening data at the concentration of 10 mm. methods described previously. preparation of compounds 4ae4d and 4f was described in our previous report [29] . a suspension of compound 1a or 1b (3 mmol) and potassium hydroxide (3 mmol) was stirred at r.t. during 5 min, later appropriate 2-chloro-n-arylacetamide (3.3 mmol) was added and the mixture was refluxed for 5 h in etoh (10 ml). obtained powders were filtered off, washed with ethanol and recrystallized with dmf:ethanol (1:2) mixtures. (2b). yield 68%, mp 220e222 c. 1 anti-trypanosomal activity of 5-(3-naphthalen-2-yl-5-aryl-4,5-dihydropyrazol-1yl)-thiazolidine-2,4-dione derivatives (1a, 2b, 2c). 137.9, 133.9, 133.3, 133.2, 130.1, 129.3, 128.9, 128.7, 128.6, 128.2, 127.6, 127.2, 127.1, 123.6 a solution of (2,4-dioxothiazolidin-5-ylidene)-acetyl chloride (3 mmol) in 5 ml of dioxane was added to a mixture of appropriate 3,5-diaryl-4,5-dihydro-1h-pyrazole (3 mmol) and triethylamine (3 mmol) in 5 ml of dioxane and later was heated to 70e80 c during 15 min, cooled and poured water (50 ml). obtained powder was filtered off, washed with water and recrystallized with dmf:ethanol (1:2) mixtures. results for each tested compound were reported as the percent of growth of the treated cells when compared to the untreated control cells. the percentage growth was evaluated spectrophotometrically versus controls not treated with test agents. the cytotoxic and/or growth inhibitory effects of the most active selected compounds were tested in vitro against the full panel of human tumor cell lines at concentrations ranging from 10 à4 to 10 à8 m. 48-h continuous drug exposure protocol was followed and an srb protein assay was used to estimate cell viability or growth. using absorbance measurements [time zero (tz), control growth in the absence of drug (c), and test growth in the presence of drug (ti)], the percentage growth was calculated for each drug concentration. percentage growth inhibition was calculated as: ½ðti à tzþ=ðc à tzþ â 100 for concentrations for which ti ! tz; ½ðti à tzþ=tz â 100 for concentrations for which ti < tz: dose response parameters (gi 50 , tgi) were calculated for each compound. growth inhibition of 50% (gi 50 ) was calculated from [(ti à tz)/(c à tz)] â 100 ¼ 50, which is the drug concentration resulting in a 50% lower net protein increase in the treated cells (measured by srb staining) as compared to the net protein increase seen in the control cells. the drug concentration resulting in total growth inhibition (tgi) was calculated from ti ¼ tz. values were calculated for each of these parameters if the level of activity was reached; however, if the effect was not reached or was excessive, the value for that parameter was expressed as more or less than the maximum or minimum concentration tested. the lowest values were obtained with the most sensitive cell lines. compounds having gi 50 values 100 mm were declared to be active. primary antiviral assay was performed on a respiratory viruses panel (flu a (h1n1), flu a (h3n2), flu a (h5n1), flu b, sars cov) [43] . compounds were diluted to 20 mg/ml in dmso then eight half-log dilutions were prepared in mem solution with 50 mg/ml gentamicin. each dilution was added to 5 wells of a 96-well plate with 80e100% confluent cells, and three wells of each dilution were then infected with the test virus using a multiplicity of infection of <0.006 ccid50 per cell for each virus. two wells remained uninfected as toxicity controls. a known active compound was run in parallel as a control. after cytopathic effect (cpe) was observed microscopically, plates were stained with neutral red dye for approximately 2 h, then supernatant dye was removed from the wells and the incorporated dye was extracted in 50:50 sorensen citrate buffer/ethanol and read on a spectrophotometer at 540 nm. the optical density of test wells was converted to percent of cell and virus controls, then the concentration of test compound required to inhibit viral cpe by 50% (ec 50 ) was calculated by regression analysis. the concentration of compound that would cause 50% cytotoxicity in the uninfected cells was similarly calculated (cc 50 ). ec 50 and cc 50 were presented in mm. the selective index (si) is the cc 50 divided by ec 50 . bloodstream forms of t. brucei brucei strain 90-13 and t. brucei gambiense feo strain were cultured in hmi9 medium supplemented with 10% fcs at 37 c under an atmosphere of 5% co 2 [44] . in all experiments, log-phase parasite cultures were harvested by centrifugation at 3000âg and immediately used. drug assays were based on the conversion of a redox-sensitive dye (resazurin) to a fluorescent product by viable cells as previously described [45] . drug stock solutions were prepared in pure dmso. t. brucei bloodstream forms (10 5 cells/ml) were cultured in 96-well plates either in the absence or in the presence of different concentrations of inhibitors in a final volume of 200 ml. after a 72-h incubation, resazurin solution was added in each well at the final concentration of 45 mm and fluorescence was measured at 530 nm and 590 nm absorbance after a further 4-h incubation. the percentage of inhibition of parasite growth rate was calculated by comparing the fluorescence of parasites maintained in the presence of drug to that of in the absence of drug. dmso was used as control. concentration inhibiting 50% of parasite growth (ic 50 ) was determined from the doseeresponse curve with a drug concentrations ranging from 10 mg/ml to 0.625 mg/ml and presented in mm. ic 50 value is the mean þ/à the standard deviation of three independent experiments. yield 82%, mp 268e270 c. 1 h nmr (400 mhz, dmso-d 6 þ ccl 4 ): d 12.71 (br. s, 1h, nh), 8.27 (s, 1h, arom), 7.95e8.11 (m, 4h, arom), 7.88 (s, 1h, ch), 7.56e7.60 (m, 2h, arom) 5-diaryl-4,5-dihydropyrazol-1-yl)-2-oxoethylidene]-2,4-dioxothiazolidin-3-yl}-n-arylacetamides (5ae5e) a suspension of compound 4b or 4f (3 mmol) and potassium hydroxide (3 mmol) was stirred at r.t. during 5 min, later appropriate 2-chloro-n-arylacetamide (3.3 mmol) was added and the mixture was refluxed for 5 h in etoh (10 ml). obtained powders were filtered off 3-phenyl-4,5-dihydropyrazol-1-yl]-2-oxoethylidene}-2,4-dioxothiazolidin-3-yl)-n-p-tolylacetamide (5a) 04 (d, 2h, j ¼ 7.9 hz, arom), 5.70 (dd, 1h, ch 2 ch dmso-d 6 þ ccl 4 ): d 10.04 (s, 1h, nh), 8.02 (s 4 -d ioxoth iazolidin-3-yl )-n-(4-chlorophenyl)-acetamide (5c). yield 79%, mp 289e290 c. 1 h nmr (400 mhz, dmso-d 6 þ ccl 4 ): d 10.51 (s, 1h, nh), 7.98 (s, 1h, coch), 7.83e7.86 (m, 2h, arom), 7.48e7.58 (m, 5h, arom), 7.34e7.42 (m, 3h, arom) -{2-[5-(4-methoxyphenyl)-3-naphthalen-2-yl-4,5-dihydropyrazol-1-yl]-2-oxoethylidene}-2,4-dioxothiazolidin-3-yl)-acetamide (5d). yield 86%, mp 268e269 c 46 (d, 2h, j ¼ 6.4 hz, arom), 7.21 (d, 2h, j ¼ 6.4 hz, arom), 6.90 (br. s, 3h, arom), 5.68 (dd, 1h, ch 2 ch 4-thiazolidones: centenarian history, current status and perspectives for modern organic and medicinal chemistry biological activities of pyrazoline derivatives e a recent development recent advances in the therapeutic applications of pyrazolines structureeactivity relationship study of a novel necroptosis inhibitor photochemically enhanced binding of small molecules to the tumor necrosis factor receptor-1 inhibits the binding of tnf-a 2-thiazolylimino/heteroarylimino-5-arylidene-4-thiazolidinones as new agents with shp-2 inhibitory action synthesis of novel thiazolone-based compounds containing pyrazoline moiety and evaluation of their anticancer activity synthesis of new 4-azolidinones with 3,5-diaryl-4,5-dihydropyrazole moiety and evaluation of their antitumor activity in vitro synthesis, cruzain docking, and in vitro studies of aryl-4-oxothiazolylhydrazones against trypanosoma cruzi synthesis and structureeactivity relationships of parasiticidal thiosemicarbazone cysteine protease inhibitors against plasmodium falciparum, trypanosoma brucei, and trypanosoma cruzi first small molecular inhibitors of t. brucei dolicholphosphate mannose synthase (dpms), a validated drug target in african sleeping sickness synthesis of 2-hydrazolyl-4-thiazolidinones based on multicomponent reactions and biological evaluation against t. cruzi synthesis and structureeactivity relationship study of potent trypanocidal thio semicarbazone inhibitors of the trypanosomal cysteine protease cruzain design, synthesis, and evaluation of 2-aryl-3-heteroaryl-1,3-thiazolidin-4-ones as anti-hiv agents synthesis and anti-hiv studies of 2-adamantyl-substituted thiazolidin-4-ones discovery of 2,3-diaryl-1,3-thiazolidin-4-ones as potent anti-hiv-1 agents design and synthesis of 2-(2,6-dibromophenyl)-3-heteroaryl-1,3-thiazolidin-4-ones as anti-hiv agents synthesis and evaluation of 2-(2,6-dihalophenyl)-3-pyrimidinyl-1,3-thiazolidin-4-one analogues as anti-hiv-1 agents predicting anti-hiv activity of 1,3,4-thiazolidinone derivatives: 3d-qsar approach design, microwave-assisted synthesis and hiv-rt inhibitory activity of 2-(2,6-dihalophenyl)-3-(4,6-dimethyl-5-(un)substituted-pyrimidin-2-yl)thiazolidin-4-ones non-nucleoside inhibitors of the hepatitis c virus ns5b rna-dependant rna polymerase: 2-aryl-3-heteroaryl-1,3-thiazolidin-4-one derivatives synthesis and biological activity of 4-(3-aryl-4-oxo-2-thioxothiazolidin-5-ylimino)-3-methyl-1-(n,n-disubstituted aminomethyl) pyrazolin-5-ones synthesis and antiviral activity of new pyrazole and thiazole derivatives synthesis and anticancer and antiviral activities of new 2-pyrazoline-substituted 4-thiazolidinones synthesis and antidepressant activities of some 3,5-diphenyl-2-pyrazolines synthesis and antihyperglycemic activity of novel 5-(naphthalenylsulfonyl)-2,4-thiazolidinediones synthesis and in vitro anticancer activity of 2,4-azolidinedione-acetic acids derivatives structureeanticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives synthesis and evaluation of antitumor activity of 5-[2-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-2-oxoethylidene feasibility of a high-flux anticancer drug screen using a diverse panel of cultured human tumor cell lines some practical considerations and applications of the national cancer institute in vitro anticancer drug discovery screen cancer drug discovery and development the nci60 human tumour cell line anticancer drug screen synthesis and anticancer activity of novel nonfused bicyclic thiazolidinone derivatives, phosphorus new 5-arylidene-4-thiazolidinones and their anticancer activity a facile synthesis and anticancer activity evaluation of spiro thiazolidinone motif in anticancer drug discovery. experience of dh lnmu medicinal chemistry scientific group synthesis and anticancer activity evaluation of 4-thiazolidinones containing benzothiazole moiety synthesis and anticancer activity of isatin-based pyrazolines and thiazolidines conjugates synthesis and antitumor activity of novel 2-thioxo-4-thiazolidinones with benzothiazole moieties synthesis of new 4ethiazolidinone-, pyrazoline-, and isatin-based conjugates with promising antitumor activity study of molecular mechanisms of proapoptotic action of novel heterocyclic 4-thiazolidone derivatives in vitro and in vivo assay systems for study of influenza virus inhibitors prolyl oligopeptidase of trypanosoma brucei hydrolyzes native collagen, peptide hormones and is active in the plasma of infected mice new protein farnesyltransferase inhibitors in the 3-arylthiophene 2-carboxylic acid series: diversification of the aryl moiety by solid-phase synthesis we are grateful to dr. v.l. narayanan from drug synthesis and chemistry branch, national cancer institute, bethesda, md, usa, for in vitro evaluation of anticancer activity. evaluations of compounds for antiviral activity were supported by funds from contract n01-ai-15435 from the virology branch, division of microbiology and infectious diseases, national institute of allergy and infectious diseases, national institutes of health, bethesda, md, usa. key: cord-277077-kwaiorp8 authors: tița, ovidiu; constantinescu, maria adelina; tița, mihaela adriana; georgescu, cecilia title: use of yoghurt enhanced with volatile plant oils encapsulated in sodium alginate to increase the human body’s immunity in the present fight against stress date: 2020-10-19 journal: int j environ res public health doi: 10.3390/ijerph17207588 sha: doc_id: 277077 cord_uid: kwaiorp8 (1) background: the covid–19 pandemic and the imposition of strict but necessary measures to prevent the spread of the new coronavirus have been, and still are, major stress factors for adults, children, and adolescents. stress harms human health as it creates free radicals in the human body. according to various recent studies, volatile oils from various aromatic plants have a high content of antioxidants and antimicrobial compounds. an external supply of antioxidants is required to destroy these free radicals. the main purpose of this paper is to create a yoghurt with high antioxidant capacity, using only raw materials from romania; (2) methods: the bioactive components used to enrich the cow milk yoghurt were extracted as volatile oils out of four aromatic plants: basil, mint, lavender and fennel. initially, the compounds were extracted to determine the antioxidant capacity, and subsequently, the antioxidant activity of the yoghurt was determined. the 2,2-diphenyl-1-picrylhy-drazyl (dpph) method was used to determine the antioxidant activity; (3) results: the results show that cow milk yoghurt enhanced with volatile oils of basil, lavender, mint and fennel, encapsulated in sodium alginate has an antioxidant and antimicrobial effect as a staple food with multiple effects in increasing the body’s immunity. the antioxidant activity proved to be considerably higher than the control sample. the highest antioxidant activity was obtained on the first day of the analysis, decreasing onwards to measurements taken on days 10 and 20. the cow milk yoghurt enriched with volatile basil oil obtained the best results; (4) conclusions: the paper shows that yoghurts with a high antioxidant capacity were obtained, using only raw materials from romania. a healthy diet, compliance with safety conditions and finding appropriate and safe methods to increase the body’s immunity is a good alternative to a major transition through harder times, such as pandemics. the creation of food products that include natural antioxidant compounds combines both the current great possibility of developing food production in romania and the prevention and reduction of the effects caused by pandemic stress in the human body. according to the food and agriculture organization (fao) of the united states, agri-food production will increase by about 70% in the coming decades [1] . in 2019, romania exported food and animals worth 4.77 billion euros, while imports were over 6.7 billion euros, according to data from the national institute of statistics. the crisis generated by the coronavirus could after several types of research, it was discovered that the volatile oils extracted from different plants bring an extraordinary benefit to the health of consumers. these oils have antiseptic action especially on pathogenic bacteria such as listeria monocytogenes, listeria innocua, salmonella typhimurium. antioxidant activity is another benefit of volatile oils. free radicals cause oxidation of biomolecules, including proteins, amino acids, deoxyribonucleic acid (dna), etc., and eventually cause molecular changes related to ageing, arteriosclerosis and cancer [4] . fennel (foeniculum vulgare) is an aromatic plant that belongs to the apiaceae family and is considered one of the oldest plants cultivated in the world. this is an annual, biennial or perennial plant native to the mediterranean area grown for its aromatic fruits, which are used as culinary spices. it grows especially well in coastal climates and riverbanks [19, 20] . fennel essential oils are used as a flavoring agent in foods such as beverages, bread, pickles, pastries and cheese. it is also used as a component in cosmetics and pharmaceuticals. fennel medicines and fennel essential oils have hepatoprotective effects as well as antispasmodic effects. additionally, volatile fennel oil is known for its diuretic, anti-inflammatory, analgesic and antioxidant activity [21] . the antioxidant and antimicrobial activity of volatile fennel oil is offered by the high content of trans-anethole (63.30%), pinene (11.11%) and fenchone (8.32%) [20] [21] [22] [23] [24] [25] basil (ocimum basilicum) is an aromatic plant that belongs to the lamiaceae family and is considered a rich source of essential oils. the basil plant is native to asia, africa, south and central america [26] . volatile basil oil has antimicrobial, antihistaminic, anti-inflammatory, anthelmintic, antioxidant properties, has an immunomodulatory effect, it is an antidepressant, antidiabetic and anti-hyperlipidemiac, has a hepatoprotective, neuroprotective and cardioprotective effect and it linked to anticancer activity [27] . due to the content of estragole (41.40%), 1,6-octadien-3-ol, 3,7-dimethyl (29.49%), trans-alpha-bergamotene (5.32%), eucalyptol (3.51), citral (3.31%), n-cyano-3-methylbut-2-enamine (3.08%), cis-alpha-bisabolene (1.92%), levomenthol (1.81%), and beta-myrcene (1.11%), volatile oil basil has a good antimicrobial and antioxidant activity [28] [29] [30] [31] [32] [33] . mint (mentha piperita) is an aromatic plant that is part of the lamiaceae family and is widely grown in europe, asia, egypt, south africa and arabia [34] . mint leaves are traditionally used as a tea in the treatment of headaches, fever, digestive disorders and various minor conditions. in modern medicine, mint is widely used in the treatment of gastrointestinal disorders [35] . many studies that have evaluated the antioxidant activities of volatile mint oil have focused exclusively on chemical tests, while the effectiveness of volatile mint oil in preventing oxidative stress at the cellular level or in a living organism has not been characterized [36] . the main components of the mint volatile oil are menthol, menthone, menthofuran, isomenthone, (e)-caryophyllene, 1,8-cineole, linalool, limonene, carvone, pulegone and α-terpineol. they give the volatile mint oil an antioxidant and antimicrobial capacity [37] [38] [39] . lavender (lavandula angustifolia) is an aromatic plant that belongs to the lamiaceae family. lavender is a herbaceous plant native to the mediterranean area and is widely cultivated. the smell of lavender improves mood, reduces mental stress and anxiety, and improves sleep [40] . lavender essential oil is commonly used in aromatherapy and various complementary medicines and cosmetics [41] . numerous studies have shown that volatile lavender oil has antioxidant, antimicrobial and antifungal properties [42] . the antioxidant and antimicrobial capacity of lavender volatile oil is offered by compounds such as the monoterpenoids, linalool, linalyl acetate, 1,8-cineole, β-ocimene, terpinen-4-ol, and camphor [43] [44] [45] [46] . in recent years, romanian entrepreneurs have focused on cultivating aromatic and medicinal plants. they focused especially on plants that are found in the mediterranean area. if until a few years ago we met many crops of vegetables or plants specific to the romanian area, in recent years many crops of lavender, fennel, mint or basil have appeared. the lavender culture is found in the plain and depression area of romania because the plant needs a warm and moderately dry climate. the fennel culture is most often found in the southern part of romania, where it is mostly plain and there is a warm climate. the mint culture is the most common in the depression area of romania because it is a plant that has a moderate tolerance to drought, requiring numerous irrigations. basil crops are most often found in southern romania, more precisely in the plains because the plant prefers a warm climate. basil is in first place at the top of romanians' preferences in terms of cultivating aromatic and medicinal plants [47] [48] [49] [50] [51] . in the study by kokina et al. in 2019 lavender and peppermint volatile oils have been shown to have the highest antioxidant capacity. they combined two methods, dpph and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (abts), to increase the efficiency of the evaluation of the antioxidant activity of the volatile oils studied. volatile oils were stored for 12 months and a significant decrease in antioxidant activity was observed [52] . in the study conducted by köksal and gülçin in 2008 and 2010, they demonstrated that cauliflower and lintite extracts have strong antioxidant activity [53, 54] . in 2016, aslam et al. conducted a study that demonstrated the antioxidant capacity of spinach leaves [55] . numerous studies conducted in recent years have shown that regular consumption of dairy products can have a protective effect against the development of obesity and cardiovascular disease [5] . yoghurt consumption has increased worldwide due to its nutritional value, therapeutic effects and functional properties [20] . it is very important to know the morphology of the plant and its active substances. from this point of view, the selective use of useful compounds from the plant that can be directed exactly to obtain the expected effect is preferred, and less of the plants that have been proven to produce unwanted and sometimes toxic interactions [56] . the oils obtained, once analyzed and the useful components identified, offer the possibility of their exact dosage in yoghurt so that the antioxidant effect can be ensured without substantially changing the taste and smell of the product [57, 58] . stress in the environment, especially heavy metal pollution, leads to the production of oxidative stress in plants. the population is constantly growing and the problems related to the supply of food are becoming more and more pressing. finding viable solutions for the realization of basic food products, with the widest possible destination, which in addition to a longer life cycle can ensure at the same time a healthy lifestyle, is of utmost importance. plants develop numerous enzymatic and non-enzymatic antioxidant mechanisms for detoxification. aromatic plants are especially rich in antioxidant phenolic compounds. their antioxidant activity is due to the redox properties and chemical structure, which play an important role in neutralizing free radicals and peroxides [20] . in a study conducted in 2019 on a sample of 1000 people in romania, it was shown that 98% of them suffer from diseases caused by stress. work related issues and the insecurity of tomorrow are the main reasons for the respondents' anxiety [59] . as last year in romania, the uncertainty of tomorrow and employment were the most widespread causes of stress, this year the world situation impacted by the covid-19 crisis will only deepen this even more. the large numbers of illnesses reported in the country at the moment, as well as the severely affected economic situation, are the most important causes of stress. social distancing, isolation and lack of certainty at work affects many people, who even reach states of anxiety and depression. stress development is associated with an increase in the number of free radicals, a decrease in the levels of antioxidant enzymes and an increase in oxidative lipids in the brain tissues. this free radical activity is associated with impaired cognitive function. major stress for a single period of eight hours increases the level of oxidative stress and the attack of free radicals on the brain, being accompanied by the weakening of memory and cognitive function. antioxidant nutrients have been shown to alleviate these effects when administered before or after stress-induced circumstances [60] . antioxidants are widely used as food additives to avoid food degradation. antioxidants also play an important role in preventing a variety of lifestyle disorders and ageing conditions, as they are closely linked to active oxygen and lipid peroxidation [54] . vegetable foods contain more antioxidants than those of animal origin, so the world health organization (who, geneva, switzerland) recommends about 400-600 g of vegetables and fruits daily to reduce the risk of cardiovascular disease, cancer, cognitive impairment and other eating disorders [61] . according to studies, it has been shown that the intake of antioxidants in the form of artificial supplements has not always brought the desired effect, so replacing them with natural antioxidants from plants can improve the desired effect. the intake of antioxidants, especially in this period when stress is present at maximum levels, is essential. the creation of food products that include natural antioxidant compounds combines both the current great possibility of developing food production in romania and the prevention and reduction of the effects caused by pandemic stress in the human body. to determine the antioxidant capacity, we used the dpph method. the dpph method measures the radical scavenging activity of antioxidants against free radicals, such as the dpph radical [62] . the main purpose of this work is to create yoghurts with high antioxidant and antimicrobial capacity using only raw materials from romania. external intake of antioxidants is essential to reduce the effects of daily stress. volatile oils are an excellent source of antioxidants, and their use in food production can be a great direction for the current situation. additionally, by using volatile oils, we aim to eliminate artificial preservatives added to yoghurts. according to studies in recent years, food preservatives harm consumer health, so using volatile oils with antimicrobial activity avoids the use of synthetic ones. to achieve this objective, we decided to enrich cow milk yoghurt with volatile oils encapsulated in sodium alginate. we used volatile oils from four aromatic plants: lavender, fennel, mint and basil. to achieve our purpose, we used the dpph method to determinate antioxidant capacity, and the measurements were made on the first day after making yoghurt from cow's milk, after 10 days and after 20 days. for each determination, we had two samples, a test sample (yoghurt with volatile oils) and a control sample (yoghurt without volatile oils). the yoghurt samples were packed in 150g plastic cups and stored in the refrigerator at a temperature between 0-4 • c. during the entire storage period, the glasses were covered with aluminum foil. we used five samples, first called control sample (yoghurt in which no alginate capsules were added with volatile oil), the second one called the yoghurt sample with the addition of volatile mint oil, the third one called the yoghurt sample with volatile basil oil, the fourth one called the yoghurt sample with volatile fennel oil and the fifth one called the yoghurt sample with volatile lavender oil. we used the dpph method to determinate antioxidant capacity, and the measurements were made on the first day after making yoghurt from cow milk, after 10 days and after 20 days. the cow's milk was taken from a farm in the sibiu area. lavender, mint and basil were taken from a culture located in the mures , area, and fennel was taken from a culture in the ialomit , a area. in 2019-before deciding to make a food product with a high content of antioxidants-we conducted a market study and a sensory analysis for these types of yoghurts so that we can conclude whether the products made by us are to the liking of consumers. following the sensory analysis, the tasters stated that the volatile oil added to the yoghurt only slightly influences its taste. the specific taste of yoghurt is predominant, only at the end, stimulating a slight taste of the plant from which the volatile oil is extracted. in addition to these two methods, we determined the ph and the lactic acid content to determine the antimicrobial activity of the yoghurt samples. to verify the antimicrobial activity of volatile oils, we created a mixture of the four oils studied and tested them on different cultures of enterobacteria, yeasts and molds. for the mixture of volatile oils, we used 25% volatile mint oil, 25% volatile lavender oil, 25% volatile basil oil and 25% volatile fennel oil. after obtaining the dilutions, the sowing took place on different culture mediums. the volatile oil mixture had a strong effect on colonies of enterobacteria, yeasts and molds: zero colony-forming units (cfu). no colony developed compared to the comparison plates (standard) [63] . to make the yoghurt enriched with bioactive components extracted from aromatic plants we used raw cow's milk with a physico-chemical composition representative of the lactation period, which we pasteurized, then cooled it and added lactic crops. for the inoculation operation, we used a starter culture from hansen (product name: f-dvs yc-x11 yo-flex). this is a thermophilic culture formed from lactobacillus delbrueckii subsp. bulgaricus and streptococcus thermophillus. the volatile oils did not influence the process of obtaining yoghurt. volatile oil compounds are gradually released into yoghurt due to its encapsulation in sodium alginate. the gradual release of antimicrobial and antioxidant action of volatile oils ensures a longer time of action and an avoidance of losses. for the extraction of volatile oils, we used mint, basil, lavender-dried and crushed aerial parts-and fennel seeds. the volatile oils were extracted by steam entrainment using the neo-clevenger apparatus modified by moritz. the extraction time was five hours for each sample, and for efficient extraction, the plants were soaked the day before. at the end of the extraction, the volatile oil obtained was measured and 1 ml of benzene is added over it. it was then placed in a glass vial containing sodium sulfate anhydrous to remove any traces of water. using a pasteur pipette, we extracted the volatile oil from the glass vial and the benzene evaporated. to preserve the characteristics of the volatile oil until analysis, it was sealed in a dark ampoule and refrigerated. the 4 samples of alginate capsules were obtained from 25 g 2% sodium alginate solution and 30 µl volatile basil, mint, fennel and lavender oil. the alginate solution was added gradually to the calcium chloride solution under centrifugation, thus obtaining the alginate capsules which were then washed with distilled water [63] . for the extraction of the compounds to determine the antioxidant capacity of the yoghurt samples with volatile oils, we used the extraction method adapted after patel et al. (2016) . we weighed 0.5 g of the sample to be analyzed and then extracted it with 10 ml of the mixture methanol:water:hydrochloric acid 0.12 m = 70:29:1 (v/v/v), at room temperature, for 24 h. the mixture was then kept on the ultrasonic water bath for 30 min at a temperature of 25 • c. after the time ran out, the supernatant was collected and centrifuged at 8000 rpm for 10 min. the residue was suspended in 10 ml of solvent to perform a second extraction for 15 min, on the bath of water at 25 • c. the resulting supernatant was centrifuged under the same conditions as the first. the total amount of supernatant was evaporated to the rotary evaporator and the residue was taken up with 10 ml of methanol. we filtered the mixture of supernatant and methanol and filled it to a volume of 10 ml with the same solvent [64] . to determine the antioxidant activity of the yoghurt samples with the addition of volatile oils encapsulated in sodium alginate, we used a method adapted according to the method applied by tylkowski et al. (2011) for the ethanolic extracts of sideritis ssp. l. we prepared a 25 µg/ml dpph solution by solubilizing a quantity of dpph in absolute methanol -stock solution.this mixture needed to be prepared in advance-at least 1-2 h-for complete solubilization. a volume of 970 µl dpph solution 25 µg/ml is measured and added over 30 µl methanol extract from the samples to be analyzed, which we obtained using the extraction shown above. to interpret the results, we measured the absorbance at 515 nm for each sample using the cecil 1021 uv-vis spectrophotometer and the concentration is determined according to the standard curve obtained from different concentrations of the stock solution [65] . the determination of antioxidant activity was performed for each sample of yoghurt. for all these samples, there were 10 spectrophotometer readings, because from each type of yoghurt we made five samples (five containers of 100 g each). after extracting the necessary compounds to determine the antioxidant activity of each extracted container we took two readings. we wanted to eliminate all errors related to equipment, human error and differences in temperature or humidity. all readings were made on the same day of the analysis, to be more exact on the first day, on the 10th day and on the 20th day after the yoghurt samples were made. the results obtained in this research are presented as follows. figure 1a shows the antioxidant activity of the control sample on the first day, the 10th day and the 20th day. on the first day of the analysis, the highest values of the antioxidant activity of the control sample were obtained. on this day, the maximum value obtained was 0.23%, and the minimum value was 0.16%. the value of the antioxidant activity for the control sample decreased on the 10th day compared to the first day. on day 10 of the analysis, the highest value obtained was 0.16%, and the lowest value was 0.10%. the lowest values of antioxidant activity for the control sample were obtained on day 20 of the analysis. on this day, the highest measured value was 0.11%, and the lowest was 0.06%. the average value for each day was 0.20% for the first day, 0.13% for the 10th day and 0.08% for the 20th day. figure 1a shows the antioxidant activity of the control sample on the first day, the 10th day and the 20th day. on the first day of the analysis, the highest values of the antioxidant activity of the control sample were obtained. on this day, the maximum value obtained was 0.23%, and the minimum value was 0.16%. the value of the antioxidant activity for the control sample decreased on the 10th day compared to the first day. on day 10 of the analysis, the highest value obtained was 0.16%, and the lowest value was 0.10%. the lowest values of antioxidant activity for the control sample were obtained on day 20 of the analysis. on this day, the highest measured value was 0.11%, and the lowest was 0.06%. the average value for each day was 0.20% for the first day, 0.13% for the 10th day and 0.08% for the 20th day. in figure 1a , the decline is calculated on day 10 and day 20 compared to the first day for the control sample. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 52-88%. the decline from day 20 compared to the first day is between 27-58%. in figure 1a , the decline is calculated on day 10 and day 20 compared to the first day for the control sample. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 52-88%. the decline from day 20 compared to the first day is between 27-58%. figure 2a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile mint oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the strongest antioxidant activity of the yoghurt sample with volatile mint oil was on the first day. the lowest value of this day was 1.57%, and the highest was 1.62%. the value of the antioxidant activity decreased on the 10th day compared to the first day. on day 10 the highest value was 1.23%, and the lowest at 1.17%. for this yoghurt sample, the lowest antioxidant activity was recorded on day 20. the highest value on day 20 was 1.06%, and the lowest was 0.95%. the average value for each day is 1.60% for the first day, 1.20% for the 10th day and 1.00% for the 20th day. figure 2a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile mint oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the strongest antioxidant activity of the yoghurt sample with volatile mint oil was on the first day. the lowest value of this day was 1.57%, and the highest was 1.62%. the value of the antioxidant activity decreased on the 10th day compared to the first day. on day 10 the highest value was 1.23%, and the lowest at 1.17%. for this yoghurt sample, the lowest antioxidant activity was recorded on day 20. the highest value on day 20 was 1.06%, and the lowest was 0.95%. the average value for each day is 1.60% for the first day, 1.20% for the 10th day and 1.00% for the 20th day. in figure 2b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile mint oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 73-78%. the decline from day 20 compared to the first day is between 61-66%. figure 3a shows the antioxidant activity of the yoghurt sample from cow's milk with the addition of volatile basil oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. on the first day, the yoghurt sample with volatile basil oil showed the highest antioxidant activity, and on the 20th the lowest. the highest value from the first day was 9.65% and the lowest at 9.56%. on day 10 the highest value was 9.33%, and the lowest at 9.26%. on day 10 the antioxidant activity was lower than on the first day, but it was higher than on day 20. day 20 showed the lowest antioxidant activity, and the lowest value was 8.65%. the average value for each day is 9.60% for the first day, 9.30% for the 10th day and 8.70% for the 20th day. in figure 2b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile mint oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 73-78%. the decline from day 20 compared to the first day is between 61-66%. figure 3a shows the antioxidant activity of the yoghurt sample from cow's milk with the addition of volatile basil oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. on the first day, the yoghurt sample with volatile basil oil showed the highest antioxidant activity, and on the 20th the lowest. the highest value from the first day was 9.65% and the lowest at 9.56%. on day 10 the highest value was 9.33%, and the lowest at 9.26%. on day 10 the antioxidant activity was lower than on the first day, but it was higher than on day 20. day 20 showed the lowest antioxidant activity, and the lowest value was 8.65%. the average value for each day is 9.60% for the first day, 9.30% for the 10th day and 8.70% for the 20th day. in figure 2b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile mint oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 73-78%. the decline from day 20 compared to the first day is between 61-66%. figure 3a shows the antioxidant activity of the yoghurt sample from cow's milk with the addition of volatile basil oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. on the first day, the yoghurt sample with volatile basil oil showed the highest antioxidant activity, and on the 20th the lowest. the highest value from the first day was 9.65% and the lowest at 9.56%. on day 10 the highest value was 9.33%, and the lowest at 9.26%. on day 10 the antioxidant activity was lower than on the first day, but it was higher than on day 20. day 20 showed the lowest antioxidant activity, and the lowest value was 8.65%. the average value for each day is 9.60% for the first day, 9.30% for the 10th day and 8.70% for the 20th day. in figure 3b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile basil oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 96-97%. the decline from day 20 compared to the first day is between 90-91%. figure 4a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the highest antioxidant activity was on the first day and the lowest on the 20th day. on the first day, the highest value was 6.43%, and the lowest value was 6.37%. the antioxidant activity on day 10 is lower than on the first day. the highest value on the 10th day was 6.18%, and the lowest was 6.22%. on day 20, the yoghurt sample with volatile fennel oil had the lowest antioxidant activity. the highest value recorded was 6.04%, and the lowest was 5.95%. the average value for each day was 6.40% for the first day, 6.20% for the 10th day and 6.00% for the 20th day. figure 3 . (a) antioxidant activity of the yoghurt sample from cow milk with the addition of volatile basil oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day; (b) decline on day 10 and day 20 for the yoghurt sample from cow milk with the addition of volatile basil oil encapsulated in sodium alginates compared to day one. in figure 3b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile basil oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day is between 96-97%. the decline from day 20 compared to the first day is between 90-91%. figure 4a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the highest antioxidant activity was on the first day and the lowest on the 20th day. on the first day, the highest value was 6.43%, and the lowest value was 6.37%. the antioxidant activity on day 10 is lower than on the first day. the highest value on the 10th day was 6.18%, and the lowest was 6.22%. on day 20, the yoghurt sample with volatile fennel oil had the lowest antioxidant activity. the highest value recorded was 6.04%, and the lowest was 5.95%. the average value for each day was 6.40% for the first day, 6.20% for the 10th day and 6.00% for the 20th day. in figure 4b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day was between 96-97%. the decline from day 20 compared to the first day was between 93-95%. figure 5a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile lavender oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the highest antioxidant activity of the yoghurt sample with volatile lavender oil was on the first day, and the lowest was on the 20th day. the highest value on the first day was 5.23%, and the lowest was 5.17%. the antioxidant activity on the 10th day was lower than on the first day, but it was higher than on the 20th day. the highest value on day 10 was 5.13%, and the lowest was 5.07%. on day 20, the lowest antioxidant activity was recorded, and the lowest value was 4.67%. the average value for each day was 5.20% for the first day, 5.10% for the 10th day and 4.70% for the 20th day. figure 4 . (a) antioxidant activity of the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day; (b) decline on day 10 and day 20 for the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates compared to day one. in figure 4b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile fennel oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day was between 96-97%. the decline from day 20 compared to the first day was between 93-95%. figure 5a shows the antioxidant activity of the yoghurt sample from cow milk with the addition of volatile lavender oil encapsulated in sodium alginates on the first day, the 10th day and the 20th day. the highest antioxidant activity of the yoghurt sample with volatile lavender oil was on the first day, and the lowest was on the 20th day. the highest value on the first day was 5.23%, and the lowest was 5.17%. the antioxidant activity on the 10th day was lower than on the first day, but it was higher than on the 20th day. the highest value on day 10 was 5.13%, and the lowest was 5.07%. on day 20, the lowest antioxidant activity was recorded, and the lowest value was 4.67%. the average value for each day was 5.20% for the first day, 5.10% for the 10th day and 4.70% for the 20th day. in figure 5b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile lavender oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day was between 97-99%. the decline from day 20 compared to the first day was between 89-91%. the determination of the antioxidant activity was performed for each sample of yoghurt. for all samples, 10 spectrophotometer readings were performed to eliminate all errors related to equipment, human error and differences in temperature or humidity. all readings were made on the same day of the analysis, to be more exact on the first day, on the 10th day and on the 20th day after the yoghurt samples were made. according to figure 6 , the analytical results obtained show that the highest antioxidant activity was shown by the sample of yoghurt with basil volatile oil encapsulated in sodium alginate, followed by the sample of yoghurt with fennel volatile oil encapsulated in sodium alginate, then the sample of yoghurt with lavender volatile oil encapsulated in the sodium alginate and yoghurt sample with mint volatile oil encapsulated in sodium alginate. the antioxidant activity proved to be considerably higher than the control sample. decline on day 10 and day 20 for the yoghurt sample from cow milk with the addition of volatile lavender oil encapsulated in sodium alginates compared to day one. in figure 5b , the decline is calculated on day 10 and day 20 compared to the first day for the yoghurt sample from cow milk with the addition of volatile lavender oil encapsulated in sodium alginates. the decline on day 10 compared to the first day is smaller than the decline on day 20 compared to the first day. the results obtained on day 20 are lower compared to day 10. the decline from day 10 compared to the first day was between 97-99%. the decline from day 20 compared to the first day was between 89-91%. the determination of the antioxidant activity was performed for each sample of yoghurt. for all samples, 10 spectrophotometer readings were performed to eliminate all errors related to equipment, human error and differences in temperature or humidity. all readings were made on the same day of the analysis, to be more exact on the first day, on the 10th day and on the 20th day after the yoghurt samples were made. according to figure 6 , the analytical results obtained show that the highest antioxidant activity was shown by the sample of yoghurt with basil volatile oil encapsulated in sodium alginate, followed by the sample of yoghurt with fennel volatile oil encapsulated in sodium alginate, then the sample of yoghurt with lavender volatile oil encapsulated in the sodium alginate and yoghurt sample with mint volatile oil encapsulated in sodium alginate. the antioxidant activity proved to be considerably higher than the control sample. the highest antioxidant activity was obtained on the first day of the analysis, before decreasing on day 10 and day 20. in the case of yoghurt samples with volatile basil, fennel and lavender oil, the greatest decreases in antioxidant activity were recorded between the 10th and the 20th day. in the case of the yoghurt sample with volatile mint oil, the greatest decrease in antioxidant activity was recorded between the first and the 10th day. these measurements show us that volatile basil, fennel and lavender oils have a higher antioxidant activity and are more stable during the first 10 days of preservation. in the case of volatile mint oil, it has a lower antioxidant activity and begins to stabilize after 10 days of preservation. all the data obtained show us that the chosen product has a significant antioxidant capacity and can be used as an external source of antioxidants. it was thus demonstrated that there exists a way of the highest antioxidant activity was obtained on the first day of the analysis, before decreasing on day 10 and day 20. in the case of yoghurt samples with volatile basil, fennel and lavender oil, the greatest decreases in antioxidant activity were recorded between the 10th and the 20th day. in the case of the yoghurt sample with volatile mint oil, the greatest decrease in antioxidant activity was recorded between the first and the 10th day. these measurements show us that volatile basil, fennel and lavender oils have a higher antioxidant activity and are more stable during the first 10 days of preservation. in the case of volatile mint oil, it has a lower antioxidant activity and begins to stabilize after 10 days of preservation. all the data obtained show us that the chosen product has a significant antioxidant capacity and can be used as an external source of antioxidants. it was thus demonstrated that there exists a way of increasing both the food and nutritional quality of the yoghurt but also the validation of the method of increasing the shelf life of the yoghurt. acid dairy products are appreciated worldwide because of the benefits they bring to the consumer's health, as well as the possibility of consuming them from an early age [5] . in this case, we used yoghurt as a representative product for consumers, both in terms of favorable intake for the harmonious development of the body at different stages of life, but also in terms of frequency of consumption. enriching it with bioactive components extracted from native herbs mint, basil, fennel and lavender, respectively, by adding volatile oils extracted from these plants and encapsulated using 2% sodium alginate, proved to be a beneficial option to increase the value of the product. the use of sodium alginate capsules also solved the problem of ensuring the stability of the volatile oils added to the food. the statistically processed results demonstrate the validity of the method of obtaining valuable food products, enriched in bioactive components, respectively, of using volatile oils with antioxidant and antimicrobial activity. the amount of volatile oils extracted from mint, basil, fennel and lavender is dependent on the growing conditions, soil and climatic conditions, the extraction method used, but the average values obtained support the potential for their use, especially in terms of the benefits for consumers' health. the creation of foods containing natural antioxidant and antimicrobial compounds must take precedence in food management. the problem of daily stress has become a major health problem in recent years, and the global situation impacted by the covid-19 crisis deepens this further. it is a reality nowadays that social distancing, isolation and the lack of certainty at work affects many people, even reaching states of anxiety and depression. making such foods to increase the body's immunity to viruses or to alleviate many chronic health problems is an effective and safe alternative to ensuring physical and mental health. to get over this period more easily and to reduce-as much as possible the effects-caused by the stress resulted from the pandemic, doctors recommend adopting a healthier lifestyle. therefore, a healthy diet, compliance with safety conditions and especially finding appropriate and safe methods to increase the body's immunity are safe alternatives to an easier passage through harder periods such as the pandemic. the use of volatile oils also ensures the complete elimination of artificial preservatives added to dairy products in this case of yoghurts. food preservatives harm consumer health, often causing food poisoning, so using volatile oils with antiseptic and antioxidant activities ensures an increase in the shelf life of food and attention to toxicology and public health. crossref] 2. #cumreînviembusinessul: industria alimentară merge înainte. producţia de alimente, o piaţă de 50 de miliarde de lei anual, s-ar putea dubla dacă folosim materie primă locală physicochemical, functional, and sensory properties of yogurts containing persimmon antioxidant and antiseptic properties of volatile oils from different medicinal plants: a review dairy consumption at snack meal occasions and the overall quality of diet during childhood. 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random house canada therios, i. boron and maturity effects on biochemical parameters and antioxidant activity of pepper (capsicum annuum l.) cultivars comparative analysis of yoghurts obtained with bioactive compounds non-targeted metabolite profiling and scavenging activity unveil the nutraceutical potential of psyllium (plantago ovata forsk). front concentration of biologically active compounds extracted from sideritis ssp. l. by nanofiltration. food bioprod. process we would like to express our sincere gratitude to the research center in biotechnology and food engineering (c.c.b.i.a.), lucian blaga university of sibiu for the entire support granted throughout the research period. we also appreciate the editor and the anonymous reviewers for their constructive comments and insightful suggestions on the manuscript. the authors declare no conflict of interest.int. j. environ. res. public health 2020, 17, 7588 key: cord-324217-secnz2ta authors: pasdaran, a.; pasdaran, a.; sheikhi, d. title: volatile oils: potential agents for the treatment of respiratory infections date: 2016-08-05 journal: the microbiology of respiratory system infections doi: 10.1016/b978-0-12-804543-5.00016-6 sha: doc_id: 324217 cord_uid: secnz2ta due to presence of secondary bioactive metabolites, natural compounds are considered a major source of new active molecules that can be developed as new drugs. infectious diseases, and mainly the common respiratory infections, are major challenges to the current chemotherapy systems and, therefore, there is a requirement to find new compounds with therapeutic potential. the volatile natural compounds and essential oils are the main treasure agents in the natural compounds with antibiotic potential. the present chapter reviews natural traditional remedies used in the treatment of respiratory infections with the emphasis on antibacterial, antiviral, and antiinflammation activities of the volatile natural compounds (essential oils, etc.), and provides a brief view in some of structural activity relationships between antibacterial potencies and chemical structures of the essential oil’s constituents. referring to infectious disease, respiratory tract infections engage with all surfaces in the respiratory tract. based on the infected zone, respiratory infections can be categorized into upper tract infection (uri or urti) and lower tract infection (lri or lrti). each involves different parts of the respiratory tract infections, which vary in type and severity of microorganisms. although there are different types of respiratory tract infections, the acute form in the upper respiratory tract infection predominates and includes several complications, such as sinusitis, pharyngitis, epiglottitis, laryngitis, and tracheitis. on the other hand, lower respiratory tract infection (lrti) includes both acute and chorionic types, such as pneumonia and bronchitis. based on pathogenicity, bacterial and viral pathogens are the most common microorganisms in both types (ie, lrti and urti). moreover, infection distribution leads to varieties based on the patient's age; for example, acute respiratory infections pose severe problem in childhood, which mainly occur in upper respiratory tract. although the bacterial pathogens play a significant role in intensifying lrtis, the major acute respiratory infections occur in upper respiratory tract, in these cases viral pathogens are the primary common pathogens, including influenza a and b, parainfluenza (type 1 and 3), adenovirus, and respiratory syncytial virus. some of the common pathogens of the respiratory tract are listed in table 16 .1. pathogen biodiversity, complexity, and mixed infections in many cases of respiratory tract infection have generated several problems for the treatment of respiratory infections. for example, various bacterial pathogens are encountered in several cases of viral infections. therefore, the treatment of respiratory infections is a complex therapy which consists of several chemotherapy strategies. 1-3 antiviral (the same as antibacterial medication) is used to control the treatment and prevention of respiratory infections. there are several restrictive factors, such as medication resistance, recurrency, and inflammation, which will guide researchers to find new effective compounds. this will be an important field in drug development for respiratory infections. natural compounds are considered to be one of the main sources in new drug development. historically, numerous plants have been utilized as traditional medicines by people in many nations. 4 many of these plants have been investigated for their antimicrobial and antiviral properties. [5] [6] [7] [8] [9] with regard to massive variation among natural products, chemical structure diversity causes different antimicrobial potential in natural compounds. 10 besides the antimicrobial activity of the essential oils in natural products, other characteristics such as high vapor pressure, low toxicity, and antiinflammatory potential create a worthwhile theme for using of these natural compounds for new drug development in respiratory infections. parallel to the roles of the microorganisms in the pathology of respiratory infections diseases, inflammatory process also have a considerable role in the persistence and recurrence of respiratory infectious diseases. this chapter reviews the antibacterial, antiviral, and antiinflammation effects of essential oils as effective natural compounds. it will also discuss the use of these natural compounds as traditional remedies in treatment of respiratory infections. traditional medicines utilize natural sources for the treatment of the many diseases. [11] [12] [13] historically, infectious diseases have been the major human ailment. natural sources are used in a variety of forms, including water extracts, tincture or alcoholic extract and incense. 14 based on the historical uses and effective treatments that have been based on many of these traditional remedies, extensive pharmacological research of their antibacterial, antiviral, and antiinflammation activity have been performed. [15] [16] [17] abundant information about plants and active compounds in infectious diseases and inflammation related process is available. [18] [19] [20] [21] aromatic and fragrant plants are a major part of traditional therapeutic remedies, and they have shown remarkable antibacterial and antiviral activity. furthermore, many of them also have a significant antiinflammatory activity and are used as adjuvant remedies in the treatment of infection (table 16 .2 and fig. 16.1) . some of the most active extracts of traditional herbs which have been used as antibacterial and antiviral in the treatment of respiratory infections are summarized in table 16 . 3 . the use of aromatic extracts or burning plants is a common process in traditional medicine. the resultant smoke or fragrance is inhaled to treat respiratory complaints, including cough, cold, infections, and asthma. 22, 23 inhalation administration goes back to the ancient cultures and its techniques may be considered as a progressive point in respiratory complaints treatment. the direct effect of such fragrance on the respiratory tract is an advantage of this form of treatment. inhalation therapy often involves the aromatic extracts or burning of plant material, and the volatile fraction liberated during the process is inhaled to aid in the healing process. inhalation of the volatile fraction from aromatic extracts or burning plant matter is a unique method of administration and has been used traditionally to treat respiratory conditions, such as, asthma, bronchitis, and other respiratory infections including the common cold. 24 in addition, aerosol delivery of such remedies is well practiced in allopathic medicine and has the advantage of being site specific, thus enhancing the therapeutic ratio for respiratory ailments. 25 the antimicrobial effects of plants and their extracts have been recognized for a long time. essential oil is one of the most important and wide spread secondary metabolite in plants and this class of phytochemical compounds and their activities needs attention. these phytochemicals are generally isolated from plant material by distillation methods, such as, hydrodistillation and steam distillation. they contain variable mixtures of several chemical classes, such as terpenoids, specifically monoterpenes and simple phenolic compounds. some of the higher molecular structures with high molecular weight, such as sesquiterpenes and diterpenes, may be present. a variety of low molecular weight aliphatic hydrocarbons, acids, alcohols, esters or lactones, sulfur-containing compounds and other chemical groups may also be observed. among the phytochemical compounds, terpenes are responsible for many therapeutic effects in medicinal plants. [26] [27] [28] [29] [30] most terpenes are derived from the condensation of isoprene units and are categorized according to the number of these units present in the carbon skeleton. these compounds are responsible for aromaticity and fragrance in many of the plants. the antibacterial activity of volatile oils has been assessed by many researchers. [31] [32] [33] [34] this potential of essential oils has been used in many pharmaceutical, cosmeceutical, and nutraceutical applications and industrials. there are many differences between the antimicrobial effects of different essential oils. essential oils and their constituents are an attractive source in new antimicrobial compounds evaluation. 35 many of the essential oils have been tested for bactericidal and bacteriostatic effects against a wide range of microorganisms including food spoiling organisms, pathogenic bacteria, yeasts, fungi, and many others. the major differences in antimicrobial activity have been yielded of several distinctive parameters which identify antibacterial characters of the essential oils, some of the major parameters include: (1) bacterial membrane permeability, (2) the hydrophobicity/hydrophilicity of the bacterial membrane, (3) the metabolic characteristics of the microorganism, and (4) their gram-positive or negative pattern. although susceptibility of the bacteria to the essential oils is not exactly predictable, many researchers have tried to determine the relationship between the origin of the essential oils and their compounds with their antimicrobial activity. furthermore, the delivery of medications to the respiratory tract has become an increasingly important method for respiratory disease treatment. the use of inhaler medications has become an invaluable therapeutic in the treatment of different pulmonary disorders, including bronchitis, pneumonia, and others complications. 37 several studies have reported the clinical efficacy of inhalation therapy for the treatment of lung disorders. 38, 39 through the effective delivery of medication to the action site, the active compounds are delivered directly into the lungs and this can result in respiratory tract local treatment. this method achieves maximum therapeutic biebersteinii. 3 screening of the antibacterial effects of essential oils effect, small dose usage, and has fewer side-effect risks compared with those associated with larger doses. inhalation is a unique treatment with direct effects on respiratory disorder site and is based on the volatility potential of essential oils. furthermore, there is a need to develop new therapeutic agents for respiratory infections. [40] [41] [42] research has been carried out on the wide spectrum of edible plants essential oils to determine the antibacterial potential of their essential oils. the role of these plants as therapeutic agents is remarkable in many cultures. investigations have reported that thyme and oregano essential oils, based on the phenolic components [such as carvacrol (1) and thymol (2) (fig. 16. 3)] have shown a strong correlation with the inhibition of some of the pathogenic bacterial strains (eg, in escherichia coli). the correlation between the antibacterial effect of the volatile oils and their chemical compounds, including high amount of the phenolic components such as carvacrol (1) or eugenol (3), has also been confirmed. 43 other essential oils such as oregano, savory, clove, and nutmeg with high concentrations of volatile phenolic compounds inhibit gram-positive more than gram-negative pathogenic bacteria. 44 however, in some essential oils such as achillea spp. (yarrow) strong antibacterial activity was observed against the gram-negative respiratory pathogens (haemophilus influenzae, pseudomonas aeruginosa) while streptococcus pyogenes was the most resistant to the this oil. 45 the other essential oils such as peppermint and spearmint inhibit the methicillin-resistant type of staphylococcus aureus. previous reports have clarified that the essential oils containing aldehyde or phenol as a major component represent the highest antibacterial activity. these antibacterial potencies are lower in the essential oils that contain high amounts of terpene alcohols compared to the essential oils containing aldehyde or phenol as a major component. other essential oils containing terpene ketone, or ether showed much weaker activity, and oil containing terpene hydrocarbon was relatively inactive. based on these findings, essential oils such as thyme, cinnamon, lemongrass, perilla, and peppermint have demonstrated suitable effects on respiratory tract infection. 46 the tolerance of gram-negative bacteria to essential oils has been attributed to the presence of a hydrophilic outer membrane that blocked the penetration of hydrophobic essential oils to the target cell membrane because the gram-positive bacteria were more exposed to the essential oils than gram-negative bacteria, which has been reported several times. [47] [48] [49] [50] lipids are one of the principal constituents for normal cell membrane function and these compounds supply many operations, such as barrier function in the bacterial cell membrane. the external capsule of some gram-negative bacteria limits or prevents the penetration of the essential oils into the microbial cell. one of the pronounced examples of the hydrophobicity/hydrophilicity role in bacterial sensitivity to antibacterial compound is h. influenzae. it should be pointed out that the outer membrane of h. influenzae (which forms rough colonies) was more hydrophobic. hydrophobic antibiotics, such as macrolides, are more active against h. influenzae than e. coli through their shorter oligosaccharide chains than those in e. coli. the effects of the cytoplasmic membrane and/or the embedded enzymes in it have demonstrated lipophilic biocide actions. 51 it is generally recognized that the antimicrobial action of essential oils depends on their hydrophilic or lipophilic character. based on these observations, investigators are trying to indicate the relationship between structural activity of the essential oils compounds and their antibacterial activity. certain components of the essential oils can act as uncouplers, which interfere with proton translocation over a membrane vesicle and subsequently interrupt adp phosphorylation pathways (primary energy metabolism). as a member of the phytochemicals, terpenoids have been observed as a model of lipid soluble agents, which have an impact on the activities of membrane catalyzed enzymes; for 3 screening of the antibacterial effects of essential oils example, enzymes involved in respiratory pathways. particular terpenoids with functional groups, such as phenolic alcohols or aldehydes, also interfere with membrane-integrated or associated enzyme proteins, inhibiting their production or activity. a good deal of antimicrobial compounds which act on the bacterial cytoplasmic membrane cause the loss of 260 nm absorbing material. this causes an increased susceptibility to nacl, the lysosomes formation and loss of potassium ions, which results in inhibiting respiration and the loss of cytoplasmic material. investigations about the cytoplasmic membrane effects of α-pinene (4), β-pinene (5), 1,8-cineole (6) , and electron microscopy studies have shown that the essential oils containing these compounds triggered such cytoplasmic material with losing in treated bacterial cells. 31, 32 the perturbation of the lipid fraction in the plasma membrane causes antimicrobial activity of some of the phytochemicals such as α,β-unsaturated aldehydes and some of monoterpenes. although these aldehyde compounds can elicit antibacterial effects by acting on membrane functional proteins, such antibacterial effect would be achieved with modifications of membrane permeability and intracellular materials leakage. [52] [53] [54] the membrane damage leading to whole-cell lysis has been reported by oregano and rosewood essential oils which contains major components as: carvacrol (1), citronellol (7), and geraniol (8) . 26, 55 phenols such as carvacrol (1), thymol (2), eugenol (3), and other oxygenated aromatic essential oil compounds including phenol ethers [trans-anethole (9), methyl chavicol (10)] and aromatic aldehydes [cinnamaldehyde (11), cuminaldehyde (12) ] have been reported to exert both antibacterial and antifungal activity. however, this chemical class-based on the concentration used-are known as either bactericidal or bacteriostatic agents, 56 but the phenolic component's high activity may be further explained in terms of the alkyl substitution into the phenol nucleus, which is known to increase the antimicrobial activity of phenols. the alkylation has been known to change the distribution ratio between the hydrophilic and the hydrophobic phases (including bacterial phases) by the surface tension reduction or the species selectivity mutate based on the bacteria cell wall characters. 57 this does not happen with etherified or esterified isomeric molecules, it is possible by describing their relative lack of activity. 58 as a member of these compounds carvacrol (1) is one of the few components that has a break apart from effect on the outer membrane of gram-negative bacteria and causes release of lipopolysaccharide and alters cytoplasmic membrane ions transportation, similar to carvacrol (1), thymol (2) antimicrobial activity results in structural and functional alterations in the cytoplasmic membrane. 59 interestingly, eugenol (3) and isoeugenol (13) exhibit higher activity against gram-negative bacteria than gram-positive bacteria, and when cinnamaldehyde (11) is used against e. coli, its activity is similar to carvacrol (1) and thymol (2) (fig. 16.3) . these compounds alter the membrane, affect the transport of ions and atp, and change the fatty acid profile of different bacteria. 60 although in some cases alcoholic form shows better potencies compared to acetate form, the presence of an acetate moiety in the structure appeared to increase the activity of the parent compound. in the case of geraniol (8), the geranyl acetate (14) demonstrated an increase in activity against the test microorganisms. 48, 61, 62 a similar effect was also observed in the case of borneol (15) , bornyl acetate (16) , linalool (17) , and linalyl acetate (18) (fig. 16.3 ). in addition, the effectiveness of alcoholic compounds very closely depended on the bacterial cell wall, which showed different permeability to alcohol based on chain length. 44, 63 it has been suggested that an aldehyde group conjugated to a carbon double bond such as citral (19) is an extremely electronegative order, which may explain their activity, and an increase in electronegativity can raise up the antibacterial activity. 64 in addition, the under research of aldehydes potency seems to depend not only on the existence of the α,β-double bond but also on the chain length from the renal group and on microorganism tested. it seems that some electronegative compounds, mainly from the cell surface, are responsible for the inhibited growth of the microorganisms, which may interfere in biological processes involving electron transfer and respond with vital nitrogen components and alteration in the operation of membrane-associated proteins. actually, a greater electronegativity of the molecule would cause a greater encounter of intermolecular hydrogen bond formation with membrane nucleophilic groups and thus a significant irregularity in the lipidic bilayer. some studies have recommend that carbon tail length also affects the electronegativity of the aldehyde oxygen atom and thus its interaction with the nucleophilic groups of the cell membrane. 65 comparably, the similar antimicrobial activity was detected in the series of the long-chain alcohols which is demonstrated to be resulted from the alkyl chain length. 66, 67 this structural activity relationship is notable between farnesol (20) , nerolidol (21), plaunotol (22) , geranylgeraniol (23), phytol (24), geraniol (8) , and linalool (17) which act on s. aureus with damages of the cell membranes and losing of k+ ions, while similar mode of actions can be detected by the aminoglycosides such as kanamycin and streptomycin. farnesol (20) was able to damage cell membranes most effectively than other terpene alcohols. the activities of farnesol (20) , nerolidol (21) (sesquiterpenes compounds) on s. aureus were higher than that of plaunotol (22) (diterpene). the effectiveness against s. aureus are in order as follows: farnesol (19) > nerolidol (20)> plaunotol (22) > geranylgeraniol (23), phytol (24) > geraniol (8) and linalool (17) (fig. 16.3 ). it has been suggested that maximum activity against s. aureus might depend on the number of carbon atoms in the hydrophobic chain from hydrophilic hydroxyl group, which should be less than 12 but as close to 12 as possible. neither a shorter nor a longer aliphatic carbon chain, could increase such activity. 68, 69 the increased effectiveness of sesquiterpenes as enhancers of membrane permeability may stem from their structural resemblance to membrane lipids (eg, linear molecules with internal lipophilic character and a more polar terminus). 70 the bacteriostatic potential of the terpenoids was also increased when the carbonyl groups increased in structure. 63 the type of alkyl substituent incorporated into a nonphenolic ring structure is responsible for enhancement of antibacterial activity. such as an alkenyl substituent (1-methylethenyl) makes an increase in antibacterial activity, as seen in limonene [1-methyl-4-(1-methylethenyl)-cyclohexene] (25), compared to an alkyl (1-methylethyl) substituent as in p-cymene [1-methyl-4-(1-methylethyl)-benzene] (26) . furthermore, principally gram-negative were the sensitive organisms that propose alkylation control of the gram reaction sensitivity of the bacteria. an allylic side-chain seems to raise the inhibitory role of the simple phenols mainly against gram-negative organisms. this was suggested due to the majority of the antimicrobial activity of alkylated phenols in relation to phenol which has been earlier reported (fig. 16.3) . 56 it was observed that α-isomers are inactive relative to β-isomers in many compounds in stereochemistry, which is also effective in antibacterial activity observed from essential oils. 44 the (e,e)-2,4-decadienal (26) appears to be more toxic to bacterial cells than the correspondent monounsaturated aldehyde (e)-2-decenal (27) as another example of stereochemistry effectiveness in activity potential observed in the unsaturated aldehyde, but it is noticeable that two double bonds in the cis configuration in the side-chain of 2,4-decadienal (26) produce more bends and shorten the length of the carbon tail, such α,β-unsaturated aldehydes might be a good choice compared to other highly toxic sterilizers (fig. 16.3) . 53 in summary, the antimicrobial activity of essential oils depends on different amounts of specific compounds. as an example, antimicrobial properties of the essential oils with high concentrations of eugenol (3), cinnamaldehyde (11) , or citral (19) , is predictable. remarkable antimicrobial, antifungal, 3 screening of the antibacterial effects of essential oils and antiviral activity of the monoterpenes and phenols relieve from essential oils present in thyme, sage, and rosemary. due to the formation of polysaccharides that increase the resistance to essential oils there are some other essential oils, such as basil, sage, hyssop, rosemary, and oregano, which are active against e. coli, s. aureus but are less effective against pseudomonas spp. [71] [72] [73] the typical characteristic of the essential oils is hydrophobicity, which is responsible for the disruption of bacterial structures and makes an increase in permeability due to a weakness to pull apart the essential oils from the bacterial cell membrane. many cellular functions, including maintaining the energy status of the cell, membrane-coupled energy transducing processes, solute transport, and metabolic regulation result from the cell membrane permeability barrier. actually, they are responsible for leakage of the cell contents, reducing the proton motive force, reducing the intracellular atp pool via decreased atp synthesis and augmented hydrolysis are the mechanisms of action of the essential oils including the degradation of the cell wall, damaging the cytoplasmic membrane, cytoplasm coagulation, damaging the membrane proteins, increased permeability that is different from the increased membrane permeability and reducing the membrane potential via increased membrane permeability. 33, 74, 75 unfortunately, scientific investigations on the antimicrobial activity of essential oils have been retarded by the lack of appropriate susceptibility testing methods for the essential oils and because no generally approved assay method has been established for the assessment of their antimicrobial activity. many researchers have employed the disk assay method. however, the results of this method were not always in parallel with those of dilution assay methods. the differences were caused not only by differences in the solubility of the oils but also by interactions of the components in the concentrated solution used in the disk assay. 48 the dilution method could be more reliable than the disk method with regard to reproducibility and clinical relevance. when testing nonwater-soluble and highly volatile essential oils by the dilution method, it is necessary to obtain a homogeneous dispersion of the oils in the medium. chemical emulsifiers such as tween 80, tween 20 and other have been used frequently for this homogenization, but it has been reported that emulsifiers reduced the bioactivity of the oils, probably because of the formation of micelles, which inhibit adequate contact between the oil and the test organism. 48 evidence also shows that the minimum inhibitory concentration (mic) values of the essential oils under open conditions of incubation caused a two-to eight-fold rise in the mics of highly volatile oils, as compared with values obtained under sealed conditions. sealed conditions are used to examine whether essential oils showed antibacterial activity against major respiratory tract pathogens (this method was authorized by the japan society of chemotherapy to adjust for the physico-chemical properties of essential oils). the scientific information concerning the antimicrobial effectiveness of the essential oils in the vapor phase compared with direct contact case show that potential of this form of the essential oils is ambiguous, although some degree of inhibition by volatile components of the essential oils has been demonstrated in the vapor phase. in fact, more investigation into the antibacterial effectiveness of the vapor phase is required. it seems that the composition of the atmosphere generated by the essential oils is also potentially correlated with their antimicrobial behavior. this part mentioned the main antibacterial activity laboratory assay methods, as already noted. these methods do not show coordinated results in some case and this appearance is reasoned to the necessity of simultaneously running two or more methods for antibacterial activity determination of essential oils. in this method, a petri dish is commonly used as an assay chamber (5-12 cm diameter and filled with 10-20 ml of agar broth). the solidified medium in the petri dish was inoculated with an appropriate colony of the microorganisms. this inoculation was accomplished by using a solution such as physiological saline solution containing adequate colony unit (commonly 100-200 (cfu)/ml). the essential oil is incorporated into the mediums in two ways: on a paper disc or into a well (hole) which is made in the agar medium. diluted or undiluted essential oils based on the goals were added to a sterile blank filter disk (5 mm diameter) and placed on top of the cultured media in a petri dish or added to the holes. after incubation under optimal conditions such as temperature and time, two different zones were considered in view of the average diameter of changes: (1) the zone where there is no growth of the microorganism, called total inhibition; and (2), the zone where growth of the microorganisms was significantly reduced in terms of amount of colonies, compared to blank assays. the growth of the microorganisms is recognizable with instruments or can be seen visually by one of the commonly used techniques, called turbidimetry, in which the optical density changes in the growing culture (od) are measured. some commercial systems have been produced for monitoring of the microorganisms growth as well as other methods were proposed (eg, bioautography). 76 an appropriate volume (100 µl physiological saline solution) of the microorganism's colony (10-20 cfu/ml) will be inoculated to the solidified medium. each essential oil sample was diluted in suitable solvent such as ethyl ether to obtain serial dilutions (v/v). the required volume (10 µl) of each dilution was then added to sterile blank filter disks or cups and placed on the medium free cover of each petri dish. experiments were designed in two forms of petri dish positions, including direct and invert placement. the petri dishes were then sealed using sterile adhesive tape. blanks were prepared by adding the same volume (10 µl) of samples of the solvent to the filter disks or cups, and this had no effect on the viability of any of the tested organisms. after the incubation period, the minimal inhibitory concentration (mic), expressed as microliters of the essential oil per volume unit of atmosphere above the organism growing on the agar surface, that caused inhibition by comparison with control tests was measured. 77 although the modification with liquid broth is mostly practical for fungi, the serial dilution agar method is also common for bacteria and fungi. the difference is that agar broth cultures are grown in petri dishes or tubes, but liquid broth cultures are cultivated in conical flasks filled with 100 ml medium or test tubes with 2.5-5 ml medium (bacteria and moulds). the inhibitory growth index is determined for the liquid broth in conical flasks (percent changes in mould's biomass comparing to the control culture). there is an inhibitory effect of essential oil which appears in the test tube cultures and is measured turbidimetrically or with the plate count method. the estimation of essential oil activity both in agar and liquid broth would be simplified through counting the tested microorganisms that can remain in the membrane. the lowest essential oil concentration in the broth that results in the lack of visible microorganism growth changes is known as the mic. the microorganisms are then transferred from the lowest essential oil concentration medium (with no visible microorganism growth) into a new broth medium and incubation to determine the lethal activity of essential oil. 78 viruses as invasive microorganisms may cause serious respiratory illness and in some cases lifethreatening conditions, such as acute pneumonia. although acute respiratory infection rates are not very high, this condition has been steadily increasing in children and persons over 60 years of age. the rates of hospitalization and death increase substantially in these cases. multiple factors, such as decline in respiratory and immune function, likely contribute to increased morbidity. natural products in all forms including pure compounds or extracts provide massive opportunities for new antiviral-lead compounds. 4, 80 at the moment, only a few effective antiviral drugs are available for the treatment of viral diseases, especially in respiratory viral infections. therefore, finding new substances with antiviral properties is a required for medical systems. much evidence has been reported about antiviral potential of various essential oils and their constitutions on several genera of viruses. 9, 81 in some investigations the essential oils with high hydrocarbons long-chain contents such as (e,e)-2,4-decadienal (26) , showed activities against influenza virus. 82,83 on other spectrum of antiinfluenza virus compounds, sesquiterpenes and sesquiterpenes-rich essential oils showed clear effects as well as aromatic rich essential oils. [84] [85] [86] among the terpenoids compounds, terpinen-4-ol (28), terpinolene (29) , and α-terpineol (30), show inhibitory effect on influenza a/pr/8pr virus subtype h1n1. also indicated that some sesquiterpenes such as β-sesquiphellandrene (31), and tetrahydronaphthalenol (32) , showed potent antirhinoviral activity in a plaque reduction test. 87 in other researches that conducted about the antiviral essential oils and their active constitutions indicated that laurus nobilis essential oil which was characterized by the presence of β-ocimene (32), 1,8-cineole (6), α-pinene (4), and β-pinene (5), as the main constituents, showed interesting activity against sars-cov. 88 this overview caused the development of commercial therapeutics based on monoterpens compounds for viral infections especially in respiratory viral infections (fig. 16.3) . 89, 90 although, antiviral potential is an important factor for bioactivity of natural compounds, cytotoxicity effects that probably triggered host cell damaged cycles are important. therefore, this is a limiting factor for presentation of the new useful compound in treatment or control of the viral infections. viruses as invasive parasites are capable of using host cell organelles and mechanisms for reproduction, such perspicaciously reproducing process caused a creation of tenacious shield against many potent natural molecules used. therefore selective activity is an important point, as are antiviral potencies. the immune response to respiratory tract infection is a double-edged sword because many of the symptoms that accompany these infections are largely due to the microorganism's induction of cytokines and chemokines, which may result in protracted inflammatory responses. phagocytic clearance of an infecting organism by inflammatory cells is an appropriate and necessary component of the host defense system. 91 at the same time, much of the evidence points to destructive effects spectrum made by products of these inflammatory cells. 92 these products can increase mucus secretion and impair ciliary clearance, thereby setting the stage for exacerbations and recurrences of infection. primary inflammatory cell products can amplify the other steps of the inflammatory cycles and can paradoxically even impair the immune response. these observations suggest that modulating the inflammatory response may be an important aspect of definitive therapy for respiratory tract infection. the primary defense systems are the lung secretions and the mucociliary escalator, which entrap organisms and sweep them away. at the same time, the lung secretions also contain a variety of proteins that inhibit microorganisms, especially bacterial adherence for example immunoglobulin a (iga) systems, which prevents bacterial adherence to epithelial cells, inhibit bacterial growth, and attempt to neutralize bacteria. the macrophages are a secondary defense system, which not only phagocytose microorganisms but also release biochemotactic factors that recruit other defense cells such as monocytes and neutrophils that are necessary for further phagocytosis process. 93 the inflammatory response form a key part of the secondary defense system that accompanies additional proteins, such as immunoglobulins and complement factors. although neutrophil infestation is part of the natural defenses against an invading organism, it may have destructive effects on the pulmonary systems. one of the destructive factors is the proteolytic enzyme neutrophil elastase, which is preformed and stored within the neutrophil. this proteinase is released after the neutrophil is activated and migrates into the tissues and phagocytosis invasive microorganisms. it produces a condition that histologically simulates chronic bronchitis. the potential role of neutrophil elastase in the pathogenesis of pulmonary diseases is characterized by neutrophil infiltration of the airways and increased mucus secretion. 94 it has also been reported that "secretions from patients with acute bronchial infection cause a significant reduction in ciliary beat frequency and that the addition of a neutrophil elastase inhibitor can reverse this effect." 95 the increase in the mucus secretion and the decrease in ciliary beat have been found as an important feature of chronic lung disease frequently. besides the phagocytic cell immediate responses, stimulated epithelial cells and macrophages produce the potent neutrophil chemoattractant, such as interleukin-8 (il-8), which was found to be present in high concentrations in the sputum of patients with chronic inflammatory airway disease. 96 at the same time, elastase released by activated neutrophils also stimulates il-8 production by the epithelial cells. 97 therefore, when these events are initiated, they become a self-amplifying cycle. this phenomenon is observed in patients with acute pneumonia that has apparently been cured by appropriate antibiotic therapy. natural products as inflammation inhibitors have for a long time played a key role in many traditional treatment systems. several mechanisms including interaction with prostaglandin biosynthesis, interaction with other inflammatory mediators, and corticosteroid-like effects are involved in antiinflammatory action of natural products. 98 among the natural chemical compounds, significant antiinflammatory activities of plant-based essential oil have been reported by many researchers, which showed the basis for folk and traditional uses of these herbs for treatment of inflammatory diseases. the essential oils and aromatic plants have had a significant place in inflammation control in many folklore medications. this evidence supports the view that appropriate investigations about the potential of essential oils should be made and their active constituents should also be evaluated for inflammation control. monoterpene alcohols such as linalool (17) and linalyl acetate (18) and other corresponding esters which are reported as one of the major volatile components of many aromatic plants essential oil were evaluated for antiinflammatory activity. these compounds have shown promising antiinflammatory potency among the many essential oil compounds. 99 for example, 1,8-cineole (6) the major constituent of eucalyptus oil is another active essential oil constituent that is well tolerated in inhalation administrations. this compound can also be effective for airways inflammation in clinical trials, based on such finding 1.8-cineole (6) is registered as a licensed medicinal product and has been available for airways inflammation for many years. 100 similar effects were also observed in other monoterpenes especially in carvacrol (1) and thymol (2) , which are main constituents in thymus, oregano, savory, clove, and nutmeg essential oils. in other reports, similar observations have confirmed that many of the other essential oils and their constitutions can play an important role in inflammation control. emphasizing the structure-activity relationships is necessary to define different potential of natural compounds such as essential oils compositions. for instance, aliphatic aldehydes and aromatic aldehydes are said to predominantly have antiinflammatory and antimicrobial potentials. 101 the terpenes and sesquiterpenes evaluated appeared to be good inhibitors of 5-lox in vitro. there is a good correlation observed between antiinflammatory activity of the limonene (25) and the essential oils rich in limonene (25) like grapefruit, lime, and celery. other similar activity has been observed on the various inflammations pathways such as cyclooxygenase (cox) and lipoxygenases (lox) between sesquiterpenic alcohols, aliphatic aldehydes, and some phenolic esters that caused these phytochemicals considered for more investigations in respiratory inflammations during the air ways infections (fig. 16.3) . 101, 102 it has been evaluated that activity of some of the essential oils such as western red cedar (thuja plicata) to inactivate several viruses implicated in respiratory infections, and to inhibit the influenza virus-induced secretion of cytokine (il-6) in cultured human lung cells. however, the liquid essential oil phases are generally a higher irritant and possibly toxic for nasopharyngeal or oral applications, although a few reports have indicated that the vapors of some essential oils might be useful for application in inhaled vapors for respiratory infections in low concentrations. 103 because of the noteworthy role of inflammation in respiratory infectious disease persistence and recurrence, many laboratory models have been developed for inflammation and inflammation/infection-mixed respiratory complications research. some of these models, such as ovalbumin-induced respiratory allergic eosinophilia arise especially for inflammation process which responds to them, including eosinophils, neutrophils, and other immune cell infiltration to the inflammation sites. 104 in other models, in addition to this cellular pathogenesis, more attention is considered on the infection's correlation with inflammation mechanisms. 105 table 16 .5 shows some of the attributes of inflammation and inflammation/infection major models that are used in screening of the new antiinflammation compounds. respiratory infections are one of the most prevalent human health problems and they cause major difficulties for all age ranges. 106 research to find new and effective therapeutic compounds for the control and treatment of these ailments is a most attractive field in natural product screening. the massive biodiversity of natural sources, such as plants, means that the selection of the suitable starting source point is a critical step for achieving the best screening results. in particular, paying attention to the main chemical constitutions of these natural sources will help to clarify the results of this research. analysis of the relationship between the chemical structures of natural compounds has led to a better overview of the rational uses of natural compounds and natural remedies for the control and treatment of disease, and has led to the development of therapeutics. the broad diversity of the chemical makeup of essential oils has caused some uncertainty over their best selection in complementary or investigative research. therefore, a correct understanding of the relation between the potential effects and the plant's family is a useful guide for physicians and researchers. according to this finding, the volatile oils of plant families such as pinaceae have good potential for use in infectious and inflammatory respiratory diseases, in both research and treatment. these plant based essential oils have a good feasibility for presentation as therapeutics in many of the respiratory infections and inflammatory diseases. although these natural compounds have been used as complementary therapeutics, scientists must still give attention to their safety and 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pseudomonas aeruginosa in a rat model of chronic pulmonary infection respiratory viral infections in the elderly key: cord-328176-fck2ktxi authors: mahapatra, manojkumar; kulandaivelu, umasankar; saiko, philipp; graser, geraldine; szekeres, thomas; andrei, graciela; snoeck, robert; balzarini, jan; jayaprakash, venkatesan title: methyl-2-arylidene hydrazinecarbodithioates: synthesis and biological activity date: 2013-02-19 journal: chem zvesti doi: 10.2478/s11696-013-0346-4 sha: doc_id: 328176 cord_uid: fck2ktxi methyl-2-arylidene hydrazine-carbodithioate has not been of particular interest to researchers even though its metal complexes are extensively reported on due to their biological activity. this study examined the cytostatic and antiviral activity of twelve methyl-2-arylidene hydrazinecarbodithioates reported by many researchers as intermediates for the synthesis of thiosemicarbazides and the preparation of their metal complexes. compounds iic, iii, and iil with tridentate ligand features were found to have the lowest ic(50) value (6.5 μm, ≈ 1 μm, and 0.8 μm, respectively) against hl60 human promyelocytic leukemia cells. they were also most inhibitory to human embryonic lung (hel) fibroblast proliferation (5.3 μm, 17 μm, and 2.6 μm). compound iic and iil show antiviral activity against wild-type herpes simplex virus (hsv), varicella zoster virus (vzv), and acyclovirresistant hsv; however, these activities were observed at concentrations at which the compounds also markedly inhibit hl60 and hel cell proliferation. many n-substituted thiosemicarbazones were prepared by the condensation of schiff's bases of methyl-2-arylidene hydrazinecarbodithioate (mahcd) with amines (casero et al., 1980; collins et al., 1982; klayman et al., 1979 klayman et al., , 1991 scovill et al., 1982; shipman et al., 1981) . while thiosemicarbazones and their metal complexes were studied for their biological activity (beraldo & gambinob, 2004; ettari et al., 2010; jiang et al., 2006; katz, 1987; liberta & west, 1992; matesanz & souza, 2009; pandeya & dimmock, 1993; wnuk & robins, 2006; yu et al., 2009) , the intermediate mahcd was rarely studied for its metal complexation behaviour and the complexes for their biological activity (ali et al., 2002; kanwar et al., *corresponding author, e-mail: venkatesanj@bitmesra.ac.in 2008; neelam et al., 2000; saxena & tandon, 1983; singh et al., 1997) . very few investigators have reported biological activity of compounds with a dithiocarbamate side chain (cao et al., 2005; huang et al., 2009; kumar et al., 2010) . it is interesting to note that mahcd shares structural similarity with schiff's bases of n-hydroxy semicarbazides (snhs) and nhydroxy aminoguanidines (snhag) (fig. 1) . both snhs and snhag were rigorously documented for their anticancer activity and antiviral properties. it was proposed that these compounds act by inhibiting ribonucleotide reductase (rr) through metal chelation (das et al., 1999; ren et al., 2002; t'ang et al., 1985) . with this background, twelve mahcd derivatives were synthesised and evaluated for anticancer activity against hl60 human promyelocytic leukemia cells and antiviral activity against a panel of viral cell lines. synthesis of methyl hydrazinecarbodithioate (i) and substituted benzaldehyde hydrazones of methyl hydrazine carbodithioate (ii) to an ice cooled solution (< 10 • c) of 19.8 g (0.300 mol) of potassium hydroxide in 24 ml of water and 20 ml of propan-2-ol, 17.1 ml of 80 % pure hydrazine hydrate were added and constantly stirred. the amount of 18.2 ml (0.300 mol) of ice cooled carbon disulfide was added drop wise to the stirred solution, maintained at < 10 • c for over about 1-1.5 h. the bright yellow mixture formed was stirred for an additional 1 h after which ice cooled iodomethane (18.7 ml, 0.300 mol) was added drop wise over a 2 h period. stirring was continued for an additional 1 h, and the white precipitate obtained was filtered and washed with ice-cold water. the crude product was recrystallised from dichloromethane: yield of 43 %; audrieth et al. (1954) ; 81-83 • c, klayman et al. (1979) ). methyl hydrazinecarbodithioate (20.0 mmol) was dissolved in 20 ml of methanol and then, equimolar amount of aromatic/heteroaromatic aldehyde was added. the mixture was refluxed for 6-12 h and the reaction was monitored by tlc. the hot solution was poured onto crushed ice and the precipitate obtained was filtered (klayman et al., 1979; scovill et al., 1982) : yield of 60-80 %. the hl-60 human promyelocytic leukemia cell line was purchased from atcc (american type culture collection, manassas, va, usa). cells were grown in a rpmi 1640 medium supplemented with a 10 % heat inactivated fetal calf serum (fcs), 1 % l-glutamine and 1 % penicillin-streptomycin in a humidified atmosphere containing 5 % of co 2 . all media and supplements were obtained from life technologies (paisley, scotland, uk). cell counts were determined using a micro cell counter cc-108 (sysmex, kobe, japan). cells growing in the logarithmic phase of growth were used in all experiments described below. hl-60 cells (10 5 per ml) were seeded in 25 cm 2 nunc tissue culture flasks and incubated with increasing concentrations of drugs (iia-iil) at 37 • c under cell culture conditions. cell counts and ic 50 values were determined after 24 h, 48 h, and 72 h using the micro cell counter cc-108. viability of the cells was determined by trypan blue exclusion. results were calculated as the number of viable cells. antiviral assays (except anti-human immunodeficiency virus (hiv) assays) were based on the inhibition of virus-induced cytopathic effect in hel for the hcmv assays, confluent hel fibroblasts were grown in 96-well microtiter plates and infected with the human cytomegalovirus strains davis and ad-169 at 100 pfu per well. after a 2 h incubation period, the residual virus was removed and the infected cells were further incubated with a medium containing different concentrations of the test compounds (in duplicate). after incubation for 7-days at 37 • c, the virus-induced cytopathic effect was monitored microscopically after ethanol fixation and staining with giemsa dye. antiviral activity was expressed as the ec 50 or compound concentration required for the reduction of virus-induced cytopathogenicity by 50 %. the varicella zoster virus (vzv) drug susceptibility tests were performed on confluent hel cells in 96well microtiter plates by the plaque reduction assay. monolayers were infected with 20 plaque forming units (pfu) of the cell-associated virus per well. for each assay, virus controls (infected-untreated cells) were included. after a 2 h incubation period, the virus inoculum was removed and the media were replaced by different dilutions (in duplicate) of the tested molecules. serial dilutions of test compounds were incubated with the infected monolayers for five days. after a five day incubation period, the cells were fixed and stained with giemsa, and the level of the virus-induced cytopathic effect was determined by counting the number of plaques for each dilution. activity was expressed as ec 50 (effective compound concentration required to reduce virus plaque formation by 50 %) compared to the untreated control. the anti-hiv activity of the compounds was evaluated against the wild type hiv-1 strain iiib in mt-4 cell cultures using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (mtt) method. briefly, virus stocks were titrated in mt-4 cells and expressed as the 50 % cell culture infective dose (ccid50). mt-4 cells were suspended in culture medium at 10 5 cells per ml and infected with hiv at the multiplicity of infection of 0.02. immediately after viral infection, 100 µl of the cell suspension were placed in each well of a flat-bottomed microtiter tray containing various concentrations of the test compounds. the test compounds were dissolved in dmso at 50 mm or more as stock solutions. then, serial dilutions of the test compounds were made. the highest concentration tested was 100 µm of the test compound containing 0.2 % of dmso, which is by itself not toxic to cell proliferation. after four days of incubation at 37 • c, the number of viable cells was determined using the mtt method. compounds iia-iil were synthesised following the reaction sequence outlined in fig. 2 . methyl hydrazinecarbodithioate (i ) was prepared by the reaction of hydrazine hydrate (85 mass %) with carbon disulfide in the presence of potassium hydroxide at a temperature below 10 • c; followed by the addition of methyl iodide (audrieth et al., 1954) . condensation of i with aromatic aldehydes/ketones in methanol provided compounds iia-iil (klayman et al., 1991; scovill etal., 1982) . all compounds were characterised by their 1 h-nmr and fab-ms data. physicochemical characterisation data are presented table 1 and spectral data of compounds iia-iil are presented in table 2 . all compounds were tested for their anticancer activity against the hl-60 human promyelocytic leukemia cell line and the results are presented in table 3 . the compounds were also tested for their antiviral activity against herpes simplex virus-1 (kos), herpes simplex virus-2 (g), herpes simplex virus-1 tk − (kos acv r ), varicella-zoster virus (oka and 07/1), cytomegalovirus (davis and ad169), vaccinia virus, vesicular stomatitis virus, feline corona virus, feline herpes virus, human immunodeficiency virus (hiv) type 1 (iii b ) and type 2 (rod), coxsackie virus b4, respiratory syncytial virus, parainfluenza 3 virus, retable 4 . compound iil, iii, and iic showed ic 50 values against hl60 cells at the concentration of 0.8 µm, ≈ 1 µm, and 6.5 µm, respectively, after 72 h. it is interesting to note that preferably compounds with tridentate ligand characteristics (iil, iii, and iic) showed potent anti-proliferative activity against the hl60 cells (table 3 ). the activity of compound iii (2 -hydroxy acetophenone derivative) was higher than that of iic (2-hydroxy benzaldehyde derivative) and almost equally potent to iil (pyridine 2carboxaldehyde derivative). all the other compounds (iia, iib, iid-iih, and iik) were inhibitory at concentrations between 55 µm and 63 µm after 72 h, except for iij, irrespective of the nature and position of the substitution. compound iij did not exert any inhibitory activity on the hl60 cells at the maximum concentration studied (100 µm, after 72 h). all the compounds exhibited a cytotoxic concentration (cc 50 ) of ≥ 100 µm in the hela cell cultures except for iil (36 µm), (table 3) . compounds iii and iil showed the best selectivity towards the hl60 cells and therefore, further investigations are required. compounds iic and iii resemble the iron chelator 311 (n -[(2-hydroxynaphthalen-1-yl)-methylidene]pyridine-4-carbohydrazide) and iil resembles triapine (3-aminopyridine-2-carbaldehyde thiosemicarbazone). compound iii having a ketonic methyl group showed activity comparable to that of iron chelator 311 at 48 h. compound iil also exhibited an anti-proliferative activity comparable to that of triapine. the analogue of iil with a ketonic methyl group has to be considered for further improvement of its activity. it is interesting to observe that only compounds with tridentate ligand characteristics (iic, iii, and iil) have shown antiviral activity against a few viruses and are presented in table 4 . compound iil displayed pronounced antiviral activity against hsv-1 (8-42 µm), hsv-2 (9-11 µm ), vzv (6.5-42 µm), and vaccinia virus (15-45 µm). it should be noted that iil inhibits the wild-type as well as the acyclovir-resistant hsv at comparable compound concentrations (8-20 µm, table 4). compound iic with a 2-hydroxy substitution and compound iii, an acetophenone analogue of iic, show antiviral activity at somewhat higher concentrations than iil. compound iid that differs from iic by a hydroxy functional group at the para position did not show any appreciable antiviral activity. additional analogues of iic and iil are currently under further investigation. it should, however, be noted that iic, iii, and iil are poorly cytotoxic but they show pronounced cytostatic activity in proliferating hel (and hl60) cell cultures. therefore, the observed antiviral activity might not be due to direct antiviral activity but rather due to indirect inhibitory action caused by the underlying cytostatic potential of these compounds. the present investigation revealed that: i) compounds with a metal chelating functional group (iic, iii, and iil ) at their aryl end were found to be active and ii) the methyl dithioate (-cssch 3 ) group is not an bioisosteric equivalent of hydroxamate (-conhoh) or amidoxime (-cnhnhoh) (fig 1.) . the compounds investigated are known as intermediates in the synthesis of many thiosemicarbazones but their usefulness as medicinally active agents has not yet been studied. the study suggests a possibility of intermediates with specific pharmacophoric features for the intended activities that can provide a new scaffold for these activities. hydrazine derivatives of the carbonic and thiocarbonic acids. i. the preparation and properties of thiocarbohydrazide preparation, characterization and antifungal properties of nickel(ii) complexes of tridentate ons ligands derived from n-methyl-s-methyldithiocarbazate and the x-ray crystal structure of the [ni(onmes)cn]·h 2 o complex the wide pharmacological versatility of semicarbazones, thiosemicarbazones, and their metal complexes. mini-reviews in medicinal chemistry synthesis and in vitro antitumor activity of 4(3h)-quinazolinone derivatives with dithiocarbamate side chains activity of 2-acetylpyridine thiosemicarbazones against trypanosoma rhodesiense in vitro activity of 2-acetylpyridine and 2-acetylquinoline thiosemicarbazones tested in vitro in combination with other antituberculous drugs inhibition of herpes simplex virus type 1 and adenovirus type 5 by heterocyclic schiff bases of aminohydroxyguanidine tosylate falcipain-2 inhibitors synthesis and antitumor activity of novel dithiocarbamate substituted chromones neuroprotective activity of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (pan-811), a cancer therapeutic agent synthesis and mycobactericidal properties of metal complexes of isonicotinoyldithiocarbazic acid thiosemicarbazones: inhibition of the growth of pox viruses and requirement for the growth of an isatinβ-thiosemicarbazone dependent mutant 2-acetylpyridine thiosemicarbazones. 1. a new class of potential antimalarial agents 2-acetylpyridine thiosemicarbazones. 13. derivatives with antifilarial activity impact of metal coordination on cytotoxicity of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (triapine) and novel insights into terminal dimethylation imidazole derivatives as possible microbicides with dual protection antifungal and antitumor activity of heterocyclic thiosemicarbazones and their metal complexes: current status α-n-heterocyclic thiosemicarbazone derivatives as potential antitumor agents: a structure-activity relationships approach. mini-reviews in medicinal chemistry palladium(ii) complexes of ns donor ligandsderived from s-methyl-dithiocarbazate, s-benzyldithiocarbazate and thiosemicarbazide as antiamoebic agents recent evaluations of thiosemicarbazones and semicarbazones and related compounds for antineoplastic and anticonvulsant activities synthesis, biological evaluation, and quantitative structure-activity relationship analysis of new schiff bases of hydroxysemicarbazide as potential antitumor agents the potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents ii: the mechanism of action of ligands derived from salicylaldehyde benzoyl hydrazone and 2-hydroxy-1-naphthylaldehyde benzoyl hydrazone antitumor activity of some diorganotin and tin(iv) complexes of schiff bases 2-acetylpyridine thiosemicarbazones. 4. complexes with transition metals as antimalarial and antileukemic agents antiviral activity of 2-acetylpyridine thiosemicarbazones against herpes simplex virus antitumor activity studies of newly synthesized n-salicyloyl-n -(p-hydroxybenzthioyl)hydrazine and its copper(ii) complex both in vivo and in vitro optimization of the schiff bases of n-hydroxy-n -aminoguanidine as anticancer and antiviral agents ribonucleotide reductase inhibitors as anti-herpes agents thiosemicarbazones from the old to new: iron chelators that are more than just ribonucleotide reductase inhibitors key: cord-293867-c4wnr5xe authors: gürsoy, elif; dincel, efe doğukan; naesens, lieve; ulusoy güzeldemirci, nuray title: design and synthesis of novel imidazo[2,1-b]thiazole derivatives as potent antiviral and antimycobacterial agents date: 2019-12-06 journal: bioorg chem doi: 10.1016/j.bioorg.2019.103496 sha: doc_id: 293867 cord_uid: c4wnr5xe a series of novel acyl-hydrazone (4a-d) and spirothiazolidinone (5a-d, 6a-d) derivatives of imidazo[2,1-b]thiazole were synthesized and evaluated for their antiviral and antimycobacterial activity. the antituberculosis activity was evaluated by using the microplate alamar blue assay and the antiviral activity was evaluated against diverse viruses in mammalian cell cultures. according to the biological activity studies of the compounds, 5a-c displayed hope promising antitubercular activity, 6d was found as potent for coxsackie b4 virus, 5d was found as effective against feline corona and feline herpes viruses. consequently, the obtained results displayed that, 5a-d and 6d present a leading structure for future drug development due to its straightforward synthesis and relevant bioactivity. lately, much interest has been focused on the chemistry and the biological activity of fused heterocyclic systems because of their broad spectrum of physiological activities [1, 2] . among these heterocyclic compounds carrying nitrogen atom, imidazo [2,1-b] thiazole derivatives possess specific importance because of their diverse pharmacological activities. the imidazo [2,1-b] thiazole derivatives have been reported in the literature as antibacterial [3, 4] , antitubercular [5] , antifungal [6] , antitumoral [7] , antiviral [8, 9] , antihelmintic [10] , analgesic [11] , anti-inflammatory [12] , antihypertensive [13] , cardiotonic [14, 15] , diuretic [16] , herbicide [17] and insecticide [18] agents. levamisole [(6s)-2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b]thiazole] (fig. 1) , which is the levogyre isomer of antihelminthic tetramisol and contains imidazo [2,1-b] thiazole moiety, is a drug that has significant immunomodulatory properties [19] in addition to its antihelminthic activity [20] . besides the wide biological activity spectrum of imidazo[2,1-b] thiazole derivatives, also the compounds bearing hydrazide, acyl-hydrazone and spirothiazolidinone moiety, have been reported in the literature with their various effects such as antibacterial [21] , antifungal [22] , antitubercular [23] , antiviral [24] , anticonvulsant [25] and antidepressant [26] . on the other hand, the two compounds bmy-27709 and bms-199945, which are known in the literature for their antiviral activity and especially for their effects on influenza virus, have attracted the attention of researchers as compounds, that has a specific chemical character by an amide structure which connects an aliphatic cyclic system with an aromatic system [27, 28] . in this study, we further explored the scaffold containing the imidazo [2,1-b] thiazole ring as the aromatic moiety, that is linked by an amide to a spirothiazolidinone ring system as the aliphatic cyclic moiety and from this point forward, novel derivatives were synthesized (table 1) , and broadly evaluated for their antiviral and antimycobacterial activity (fig. 2) . two hit compounds were found to inhibit feline coronavirus or coxsackie b4 virus. besides, we observed some activity against mycobacterium tuberculosis, suggesting the versatility and relevance of this compound class to achieved anti-infective agents. compound 1 was obtained according to the procedure described by robert et al [29] . compound 2 was obtained according to the procedure described by robert et al [29] . compound 3 was obtained according to the procedure described by harraga et al [30] . general procedure for the synthesis of 6-(4-bromophenyl)-n 2 -(substituted/non-substituted cycloalkylidene)imidazo[2,1-b]thiazole-3-acetohydrazides (4a-d) 0,005 mol of 3 was boiled in a water bath under reflux with 30 ml of ethanol until a clear solution was obtained. 0.01 mol of cyclic ketone was added and heated for 6 h. after cooling the mixture to room temperature, it was filtered and purified by crystallization with warm ethanol or washing. [2,1-b] to a suspension of 0.005 mol of 4a-d in 30 ml of anhydrous benzene is added 2 ml of mercaptoacetic acid / 2-mercaptopropionic acid. the reaction mixture is heated under a reflux condenser using a dean-stark trap in a water bath for 6 h. it is concentrated under reduced pressure and the excess acid is neutralized with nahco 3 solution. the resulting product is kept in the refrigerator until solidified. the crude product is filtered, washed with water, dried and purified by crystallization or elution with ethanol. white solid, mp 162-163°c, yield: 54.4%. anal. calcd. for c 21 white solid, mp, 178-180°c, yield: 66.4%. anal. calcd. for c 27 white [4.4] [4, 5] the antimycobacterial activity studies of the compounds were performed by the taacf (tuberculosis antimicrobial acquisition and coordinating facility by the national institute of health of the us government). primary screening was conducted at 6.25 µg/ml against mycobacterium tuberculosis h37rv in bactec 12b medium using a broth microdilution assay the microplate alamar blue assay (maba) [31] . compounds exhibiting fluorescence were tested in the bactec 460 radiometric system. compounds affecting less than 90% inhibition in the primary screen were not generally evaluated further. compounds demonstrating at least 90% inhibition in the primary screen were retested at lower concentrations against m. tuberculosis h37rv in order to determine the actual minimum inhibitory concentration (mic) using maba. rifampin was utilized as the standard compound in the assays and each assay was replicated four times. the mic was defined as the lowest concentration affecting a reduction in fluorescence of 90% relative to controls. concurrently with the determination of mics, compounds were tested for cytotoxicity (ic 50 ) in vero cells at concentrations ≤6.25 µg/ml or 10 times the mic for m. tuberculosis h37rv (solubility in media permitting). after 72 h exposure, viability was assessed on the basis of cellular conversion of 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (mtt) into a formazan product using the promega celltiter 96 non-radioactive cell proliferation assay. compounds for which the selectivity index ic 50 :mic ratio) si > 10 were assumed to possess in vitro activity confirmed in the bactec 460 at 6.25 µg/ml. alamar blue susceptibility assay (maba). antimicrobial susceptibility testing was performed in black, clear-bottomed, 96-well microplates (black view plates; packard instrument, meriden, connecticut, usa) in order to minimize background fluorescence. outer perimeter wells were filled with sterile water to prevent dehydration in experimental wells. initial drug dilutions were prepared in either dmso or distilled deionized water, and subsequent twofold dilutions were performed in 0.1 cm 3 of 7h9gc (no tween 80) in the microplates. bactec 12b-passaged inocula were initially diluted 1:2 7h9gc, and 0.1 cm 3 was added to wells. subsequent determination of bacterial titers yielded 1 × 10 6 , 2.5 × 10 6 and 3.25 × 10 5 cfu cm −3 in plate wells for m. tuberculosis h37rv. frozen inocula were initially diluted 1:20 in bactec 12b medium followed by a 1:50 dilution in 7h9gc. addition of 0.1 cm 3 to wells resulted in final bacterial titers of 2.0x10 5 and 5x10 5 cfu cm −3 for h37rv. wells containing drugs only were used to detect autofluorescence of compounds. additional control wells consisted of bacteria only (b) and medium only (m). plates were incubated at 37°c. starting at day 4 of incubation, 20 mm 3 of 10x alamar blue solution (alamar biosciences/accumed, westlake, ohio, usa) and 12.5 mm 3 of 20% tween 80 were added to one b well and one m well, and plates were reincubated 37°c. wells were observed at 12 and 24 h for a color change from blue to pink and for a reading of ≥50,000 fluorescence units (fu). fluorescence was measured in a cytofluor ii microplate fluorometer (perseptive biosystems, framingham, massachusetts, usa) in bottom-reading mode with excitation at 530 nm and emission at 590 nm. if the b wells became pink by 24 h, the reagent was added to the entire plate. if the well remained blue or 50,000 ≤fu was twofold drug dilutions were prepared in either dmso (sigma) or distilled deionized water and delivered via a 0.5-cm 3 insulin syringe in a 50-mm 3 volume. drug-free control vials consisted of solvent with bacterial inoculum and solvent with a 1:100 dilution of bacterial inoculum (1:100 controls). vials were incubated at 37°c, and the gi was determined in a bactec 460 instrument (becton dickinson) until the gi of the 1:100 controls reach at least 30. all vials were read the following day, and the gi and daily changes in gi (δgi) were recorded for each drug dilution. the mic was defined as the lowest concentration for which the δgi was less than the δgi of the 1:100 control. if the gi of the test sample was greater than 100, the sample was scored as resistant even if the δgi was less than the δgi of the 1:100 control. the synthesized compounds (4a-d, 5a-d and 6a-d) were evaluated against diverse rna and dna viruses, using the following cellto perform the antiviral assays, the virus was added to subconfluent cell cultures in 96-well plates, and at the same time, the test compounds were added at serial dilutions. appropriate reference compounds were included such as the virus entry inhibitors urtica dioica agglutinin lectin and dextran sulfate; broad virus inhibitors ribavirin and mycophenolic acid; antiherpetic drugs ganciclovir and cidofovir; and hiv inhibitor azidothymidine and nevirapine. after 3-6 days incubation at 37°c (or the target compounds 4a-d, 5a-d and 6a-d were synthesized from 2-(6-(4-bromophenyl)imidazo [2,1-b] thiazol-3-yl)acetohydrazide by a four and five-step synthesis through the pathways shown in fig. 3 . 4-bromophenacyl bromide and ethyl 2-aminothiazole-4-acetate were dissolved in acetone and mixed in room temperature. after standing for 3 days, 2amino-3-[(4-bromobenzoyl)methyl]-4-(ethoxycarbonylmethyl)thiazolium bromide (1) was obtained [29] . thereafter, compound 1 was boiled under reflux in absolute ethanol and via the ring closure of compound 1, ethyl [6-(4-bromophenyl)imidazo[2,1-b]thiazole-3-yl]acetate hydrobromide (2) was obtained [29] . by heating the compound 2 and hydrazine hydrate in ethanol, 2-[6-(4-bromophenyl)imidazo[2,1-b]thiazole-3-yl]acetohydrazide (3) was obtained [30] . the compound 3 and cyclic ketones were heated under reflux in ethanol to yield 6-(4-bromophenyl)-n 2 -(substituted/non-substituted cycloalkylidene)imidazo [2,1-b]thiazole-3-acetohydrazides (4a-d). the reaction yields of compounds 4a-d were between the interval of 95%-72.5%. 4a-d were then reacted with mercaptoacetic acid / 2-mercaptopropionic acid in anhydrous benzene under reflux by using a dean-stark water separator. the obtained reaction mixture was eventually neutralized with nahco 3 solution and by that way 2-[6-(4-bromophenyl)imidazo[2,1-b]thiazol-3yl]-n-(2-nonsubstituted/methyl-6,7,8-nonsubstituted/alkyl/aryl-3-oxo-1-thia-4-azaspiro [4.4] non/ [4.5] dec-4-yl]acetamides (5a-d, 6a-d) were obtained. the reaction yields of the compounds 5a-d and 6a-d were between the interval of 87.8%-54.4% and 95%-54%, respectively. when the chemical structures of the synthesized compounds were examined, it was observed that the carbonyl group was not present in the compounds 4a-d whereas the same group was present in the spirothiazolidinone ring of the compounds 5a-d and 6a-d. also according to the ir spectroscopy results, the stretching band belonging to the carbonyl group was not visible in the spectrum of the compounds 4a-d whereas the mentioned band was able to be observed in the range of 1724-1707 cm −1 for 5a-d and 6a-d. the ir values belonging to the carbonyl groups of spirothiazolidinone ring of 5a-d and 6a-d were in agreement with the literature [33, 34] . in the 1 h nmr analysis, the nh 2 protons of compound 3, which were observed as a broad singlet peak (2h) at 4.38 ppm, was disappeared in compounds 4a-d, whereas the peaks of aliphatic ch 2 groups belonging to cyclic ketone arose as multiplet in the range of 3.15-1.44 ppm. when the results obtained from compounds 5a-d examined, it was determined that the peaks of s-ch 2 protons were added to the spectrum in the range of 3.68-3.60 ppm as a distinctive indicator related to the formation of the mentioned compound [33, 35, 36] . also from the 1 h nmr analysis data obtained from compounds 6a-d, it was determined that the s-ch and ch-ch 3 peaks of the spirothiazolidinone ring were in the range of 3.95-3.90 and 1.43-1.40 ppm, respectively and the values were in compliance with the literature [37, 38] . the ir, 1 h nmr, 13 c nmr and ms spectra of the novel compounds are in agreement with the assigned structures. no unacceptable side reactions were observed, and products were obtained in moderate to good yields. the broad antiviral evaluation demonstrated that compound 5d was quite effective against feline coronavirus in crfk cells (table 2) , with an antiviral ec 50 value of 4.8 µg/ml and a superior selectivity index (ratio of cytotoxic to antiviral concentration) higher than 20. 5d was four-fold less active against feline herpesvirus. similarly, two compounds (4c and 4d) had weak anti-dna virus activity in hel cells, with antiviral ec 50 values about 45 µg/ml ( table 3) . the most effective compound against feline coronavirus was 5d. when the sar analysis of 5d is evaluated by comparison with the other compounds, it can be understood that the existence of the structure of the spirothiazolidinone moiety is significant in the activity against the mentioned virus. it can also be observed that the spirothiazolidinone structure of 5d is separated from 5b-c by the 4-hydroxyphenyl substituent at the 8-position, and thus it can be concluded that the corresponding substituent is significant in the activity of the compound. additionally, the 2-position of the spirothiazolidinone structure separates 5d from 6b-d, indicating that the nonsubstitution of position 2 is crucial for the antiviral activity against the feline coronavirus. the results also displayed that, the compounds bearing spirothiazolidinone structure did not show activity against dna viruses, whereas compound 4c and 4d, which are carrying acyl-hydrazone moiety, showed activity against dna viruses. the obtained result displayed the importance of the existence of the acyl-hydrazone residue for the activity against dna viruses. also, 4-phenylcyclohexyl and 4-(4hydroxyphenyl)cyclohexyl derivatives of acyl-hydrazones have been found to further increase the activity against dna viruses. another hit compound, 6d, was somewhat active against coxsackie b4 virus (ec 50 : 10 µg/ml and selectivity index ≥2 (table 4) ). the antimycobacterial evaluation of compounds (4a-c, 5a-c) was performed. the results belonging in vitro primer analyses, that were performed against mycobacterium tuberculosis h37rv strain by using maba in bactec 12b media, were given in table 5 . according to the in vitro primer analyses, the compounds possessing any value where the mic value was equal to less than 10 µg/ml were considered as active for antimicrobial activity and further analysis of the mentioned compounds were conducted. from this point forward compounds 4a-c were not detected as active and no further antimycobacterial activity was performed for them. in contrast to compounds 4a-c, compounds 5a-c were detected as active and further antimycobacterial activity of these compounds was conducted and the results were displayed in table 6 . the obtained results displayed that, 4a-c, the acyl-hydrazone moiety containing imidazo[2,1-b]thiazole derivatives, showed no or weak antitubercular activity and the ring closure raised the antitubercular activity of the compounds as can be seen from the results related to the compounds 5a, 5b, and 5c. the fact that the conversion of acyl-hydrazone derivatives to spirothiazolidinone derivatives by ring closure increased the activity, indicates the importance of the existence of spirothiazolidinone structure for antitubercular activity. antibiotic resistance is rising to high levels sharply all over the world and new kinds of resistance mechanisms are emerging worldwide. infections such as pneumonia, tuberculosis, gonorrhea, blood poisoning are becoming harder to treat and current antibacterials are losing their effectivity day by day. designing of new effectual compounds to deal with these resistant bacterias has become one of the most important issues today. similarly, mycobacterium tuberculosis remains a leading infectious cause of death worldwide today. especially the evolution of multi-drug-resistant (mdr) strains of mycobacterium tuberculosis, is the main reason for the increased incidence of tuberculosis, therefore, the development of new antimycobacterial agents has become an obligation. another important is that needs new drug candidates are antiviral therapy and it is definitely necessary to design and develop new effective antiviral agents. in the present study, in an attempt to find novel antiviral and antitubercular agents, 12 diverse derivatives of imidazo[2,1-b]thiazole were designed and synthesized. the compounds were screened for their antiviral and antitubercular activity. the antimycobacterial activities of the compounds were tested against the mycobacterium tuberculosis h37rv strain and in the test method, each value, in which the mic value was equal to less than 10 µg/ml, was actively accepted for antimycobacterial activity. the mic values of the compounds 5a, 5b, and 5c were determined as 8.453 µg/ml, 1.566 µg/ml and 0.854 µg/ml and the molecules were found as active. also, compound 6d was found as effective for coxsackie b4 virus. the antiviral activity and cytotoxicity of the compounds against feline corona and feline herpes viruses were investigated in crfk cell cultures and in comparison with hha, uda and ganciclovir references, compound 5d was found as highly effective. the findings revealed the promising antiviral and antitubercular activity of acyl-hydrazone, spirothiazolidinone and 2-methyl-substituted spirothiazolidinone derivatives of imidazo [2,1-b] thiazole and these derivatives could be an interesting starting point for further structural optimization to obtain new promising and more potent antiviral and antitubercular agents. the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. the levamisole story the authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discusses in the manuscript. this includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.no writing assistance was utilized in the production of this manuscript. the authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the declaration of helsinki for all human or animal experimental investigations. supplementary data to this article can be found online at https:// doi.org/10.1016/j.bioorg.2019.103496. key: cord-270602-599vweqe authors: donia, marwa; hamann, mark t title: marine natural products and their potential applications as anti-infective agents date: 2003-05-22 journal: lancet infect dis doi: 10.1016/s1473-3099(03)00655-8 sha: doc_id: 270602 cord_uid: 599vweqe the oceans are a unique resource that provide a diverse array of natural products, primarily from invertebrates such as sponges, tunicates, bryozoans, and molluscs, and from marine bacteria and cyanobacteria. as infectious diseases evolve and develop resistance to existing pharmaceuticals, the marine environment provides novel leads against fungal, parasitic, bacterial, and viral diseases. many marine natural products have successfully advanced to the late stages of clinical trials, including dolastatin 10, ecteinascidin-743, kahalalide f, and aplidine, and a growing number of candidates have been selected as promising leads for extended preclinical assessment. although many marine-product clinical trials are for cancer chemotherapy, drug resistance, emerging infectious diseases, and the threat of bioterrorism have all contributed to the interest in assessing natural ocean products in the treatment of infectious organisms. in this review, we focus on the pharmacologically tested marine leads that have shown in-vivo efficacy or potent in-vitro activity against infectious and parasitic diseases. the oceans are a unique resource that provide a diverse array of natural products, primarily from invertebrates such as sponges, tunicates, bryozoans, and molluscs, and from marine bacteria and cyanobacteria. as infectious diseases evolve and develop resistance to existing pharmaceuticals, the marine environment provides novel leads against fungal, parasitic, bacterial, and viral diseases. many marine natural products have successfully advanced to the late stages of clinical trials, including dolastatin 10, ecteinascidin-743, kahalalide f, and aplidine, and a growing number of candidates have been selected as promising leads for extended preclinical assessment. although many marineproduct clinical trials are for cancer chemotherapy, drug resistance, emerging infectious diseases, and the threat of bioterrorism have all contributed to the interest in assessing natural ocean products in the treatment of infectious organisms. in this review, we focus on the pharmacologically tested marine leads that have shown in-vivo efficacy or potent in-vitro activity against infectious and parasitic diseases. although the diversity of life in the terrestrial environment is extraordinary, the greatest biodiversity is in the world's oceans, with 34 of the 36 phyla of life represented. the oceans cover more than 70% of the earth's surface and contains more than 300 000 described species of plants and animals. 1, 2 macroscopic plants and animals have adapted to all regions of the oceans, including polar, temperate, and tropical areas. the diversity in species is extraordinarily rich on coral reefs, where there are around 1000 species per m 2 in some areas, and the indo-pacific ocean has the world's greatest tropical marine biodiversity. 2 the marine environment represents a treasure of useful products awaiting discovery for the treatment of infectious diseases (figure 1). ecological pressures, including competition for space, the fouling of the surface, predation, and successfully reproducing have led to the evolution of unique secondary metabolites with various biological activities. 3 the importance that these secondary metabolites play in the control of infectious and parasitic organisms was for many years largely overlooked. in the past 30-40 years, marine plants and animals have been the focus of a worldwide effort to define the natural products of the marine environment. a small number of marine plants, animals, and microbes have already yielded more than 12 000 novel chemicals, with hundreds of new compounds still being discovered every year. these discovery efforts have yielded several bioactive metabolites that have been successfully developed by the pharmaceutical industry. 4, 5 several clinically useful drugs, investigational drug candidates, and pharmacological tools have already resulted from these marine-product discovery programmes. 4, 5 one of the marine natural products that is currently under clinical investigation as a potential new anticancer agents is the marine alkaloid ecteinascidin-743, isolated from the tunicate ecteinascidia turbinate. 6 ecteinascidin is a broad-spectrum antitumour agent and is among the most advanced compounds with clinical applications. 6 in this review, we focus on the pharmacologically tested marine leads that have shown in-vivo efficacy or potent invitro activity against infectious and parasitic diseases, including malaria, toxoplasmosis, trypanosomiasis, and viral, bacterial, and fungal infections. our objective was to highlight the most promising compounds that have the greatest potential to lead to clinically useful treatments. there was not room to review treatments for specific infectious diseases, but there are several helpful reviews for antiparasitic drugs, 7 antinematodal drugs, 8 antituberculosis agents, 9 antiviral leads, 10 and antifungal agents. 11 furthermore, there are some excellent general and extensive reviews focusing on marine natural products, such as those by capon, 12 newman and colleagues, 13 and faulkner. 14 the antifungal screening of marine samples has led to the characterisation of many unprecedented natural products in regard to antifungal activity and chemical structures. the frequency of invasive fungal infection has risen substantially with the increasing numbers of immunocompromised patients, such as those infected with hiv, receiving cancer chemotherapy, immunosuppressive therapy, or treatment with broad-spectrum antibiotics. 11 evidence is mounting that fungi display highly specific adaptations in the marine environment that include the production of unique secondary metabolites. 11 the fact that marine organisms contain secondary metabolites different from their terrestrial counterparts in structure and biological activity has led to the hypothesis that marine organisms may contain efficient antifungal compounds with different modes of action and selective antifungal activity compared with human cells. 11 jasplakinolide is the first example of a cyclodepsipeptide isolated from a sponge (figure 1) and was identified from a jaspis sp collected in fiji. 15 jasplakinolide, also named jaspamide, is a 19-membered macrocyclic depsipeptide with selective in-vitro antimicrobial activity and a minimum inhibitory concentration (mic) of 25 g/ml against candida albicans. the in-vivo topical activity of a 2% solution of jasplakinolide against a candida vaginal infection in mice is similar to that of miconazole nitrate. 15 gambieric acids are extremely potent antifungal metabolites isolated from a strain of the epiphytic marine dinoflagellate gambierdiscus toxicus. these metabolites are the first antifungal representatives of the brevetoxin-type (fused polyether rings) structures, consisting of nine contiguous ether rings and one isolated tetrahydrofuran (figure 2). gambieric acid a inhibits the growth of aspergillus niger at a concentration of 10 ng/disk. the potency of gambieric acids exceeds that of amphotericin b by 2000-fold. 16 toxic effects in mice or cultured mammalian cells are moderate for a dose of 1 mg/kg given by intraperitoneal injection. additional marine natural products with antifungal activity are listed in table 1. most antifungal compounds from marine origin are cytotoxic. consequently, they have not generally been considered promising antifungal agents for clinical applications. we have reviewed marine natural products that show potent antifungal activity, but evidence of cytotoxicity was not available for all. 11 in many cases, the assessment of whether antifungal activity outweighs cytotoxic effects will be required, followed by rational modifications to improve the therapeutic index for these molecules. the search for new antituberculosis agents has become increasingly important with the emergence of multidrugresistant strains of mycobacterium tuberculosis. despite the small number of investigators looking at marine products as potential leads against m tuberculosis, the research in this area has been productive (figure 3). anti-infectives from the sea the alkaloid (+)-8-hydroxymanzamine a is characterised by a complex heterocyclic ring system attached to a ␤-carboline moiety. (+)-8-hydroxymanzamine a was first isolated from a sponge pachypellina sp and later from an undescribed petrosiidae genus. 26 this alkaloid exhibits potent inhibitory activity against m tuberculosis h37rv, with an mic of 0·91 g/ml. 27 the likely biogenetic precursor ircinol a does not have the ␤-carboline moiety but still has an mic of 1·93 g/ml. ircinol a represents a useful candidate for assessment in vivo against m tuberculosis, since it shows low cytotoxicity and structural complexity compared with the other manzamine-type alkaloids. 27 in addition, manzamine a inhibits m tuberculosis h37rv, with an mic of 1·56 g/ml. 27 axisonitrile-3 is a cyanosesquiterpene isolated from the sponge acanthella klethra and shows potent inhibitory activity against m tuberculosis, with an mic of 2·0 g/ml. 28 pseudopteroxazole, a benzoxazole diterpene alkaloid isolated from the west indian gorgonian pseudopterogorgia elisabethae, induces 97% growth inhibition for m tuberculosis h37rv at a concentration of 12·5 g/ml without substantial toxic effects. 29 ergorgiaene, a serrulatane-based diterpene (also known as biflorane) was isolated from the hexane extract of the same west indian gorgonian, and induced 96% growth inhibition for m tuberculosis h37rv at a concentration of 12·5 g/ml. 30 litosterol is a c-19 hydroxysteroid isolated from an okinawan soft coral litophyton viridis. it inhibited 90% of the growth of m tuberculosis with an mic of 3·13 g/ml. the poor solubility of litosterol in the aqueous tissue culture media obscured assessment of cytotoxic effects. 9, 31 puupehenone induced 99% inhibition of m tuberculosis h37rv growth, with an mic of 12·5 g/ml and a 50% inhibitory concentration (ic 50 ) of 2·0 g/ml. the puupehenones are shikimate-sesquiterpene derived metabolites isolated from sponges of the order verongida and dictyoceratida, collected from the hawaiian islands. 9, 32 anthelmintic activity anthelmintics are drugs used to rid host organisms of helminth parasites. parasitism by nematodes (unsegmented worms that constitute the phylum nematoda) represents a major issue in the commercial livestock industry, and contributes substantially to malnutrition and disease in human beings. particularly difficult to eradicate is ascaris lumbricoides, the large gut worm, which causes malnutrition and obstructive bowel disease, and the soiltransmitted blood-sucking hookworms ancyclostoma duodenale and necator americanus, which lead to severe blood loss and iron-deficient anaemia, decreased food intake, impaired digestion, malabsorption, and poor growth rate. 33 despite the availability of excellent commercial anthelmintics, growing resistance to key structural classes (benzimidazoles and macrolides) necessitates the search for new bioactive agents. 33 jasplakinolide represents a potent antiparasitic as well as antifungal agent. it exhibited an in-vitro 50% effective dose of less than 1 g/ml against the nematode nippostrongylus braziliensis. 15 respectively. 34 this tetrahydrofuran inhibits the development of eggs for the infective free-living third stage of these two species. this degree of nematocidal activity is similar to that of the commercially available nematocides levamisole and closantel. unfortunately, attempts to translate this in-vitro nematocidal activity to in vivo proved unsuccessful, but is not surprising given the hydrophobic properties of this drug. 34 however, understanding of the in-vitro mode of action of these compounds may yet contribute to the discovery of new and improved anthelmintics. the amphilactams, isolated from a sponge of amphimedon sp collected in the great australian bight, feature an unusual carbon skeleton and an enamino lactone or lactam moiety (figure 4). amphilactam d has an in-vitro nematocidal activity against the free-living stages of the parasitic nematode h contortus, with an ld 99 of 0·39 g/ml. this substance inhibits larval development at the l1 stage, but has little or no activity against nematode eggs. this degree of in-vitro activity is similar to that of existing commercial anthelmintics, such as levamisole and closantel, and is thought to merit in-vivo assessment. 35 a sponge, geodia sp, collected from southern australia has yielded a potent nematocidal agent, geodin a magnesium salt, which is a macrocyclic polyketide lactam tetramic acid showing an ld 99 value of 1·0 g/ml. 36 diseases caused by protozoan parasites lead to high rates of mortality and morbidity worldwide. we have focused on the marine-derived natural products showing promising efficacy against the protozoal infections caused by leishmania sp, trypanosoma sp, toxoplasma sp, and plasmodium sp ( figure 5 ). leishmaniasis is a disease caused by an obligate intracellular parasite of the genus leishmania. types of disease range from self-healing ulcers (cutaneous leishmaniasis) to progressive nasopharyngeal infections (mucocutaneous leishmaniasis) to disseminating visceral leishmaniasis, which is generally fatal if left untreated. 37 in mediterranean countries adult visceral leishmaniasis is recognised as an aids-related opportunistic disease, largely due to reactivation of latent infections by immunosuppression. the most common drugs for the treatment of leishmaniasis contain pentavalent antimonials, such as sodium stibogluconate and meglumine antimonite, that have cardiotoxic effects at the recommended doses and consequently signify the urgent need for alternative treatments. 38 sponges of the genus plakortis are well known for their production of cyclic peroxides. two peroxides produced by the palauan sponge plakortis aff angulospiculatus are active against leishmania mexicana. the most active cyclic peroxide (ld 50 0·29 g/ml) causes lysis of the cell membrane after 24 h at a concentration of 1·0 g/ml, and a striking decrease in motility after 30 min. this peroxide is, however, less effective than ketoconazole (ld 50 0·06 g/ml). 39 toxoplasmosis can be transmitted to human beings from cats infected with the parasite toxoplasma gondii. the severity ranges from a self-limiting adenopathy to fatal encephalitis. this infection is particularly dangerous for pregnant women and immunocompromised individuals; congenital infection of infants is fatal in most cases. 40 new drugs or drug combinations that can eradicate the tissue cysts that cause relapses are urgently needed, particularly for patients intolerant to folate inhibitors (pyrimethamine, trimethoprim), which frequently cause undesirable side-effects. the remaining group of drugs used for the treatment of toxoplasmosis include the macrolides, which act only against the tachyzoite, leaving the cysts unaffected. 41 the alkaloid manzamine a displays 70% inhibition of the t gondii parasite, at 0·054 g/ml concentration, without cell toxic effects. the activity increases notably at concentrations of 0·54 g/ml and 5·40 g/ml, even though it is accompanied by an increase in the cytotoxic effects for the host cells, and was therefore selected for in-vivo assessment. a daily intraperitoneal dose of 8 mg/kg of manzamine a for 8 consecutive days, started on day 1 after infection, prolonged the survival of swiss webster mice to 20 days, compared with 16 days for untreated controls. exploration of new manzamines, structure-activity relation studies, and studies of optimum dose will be important to improve the in-vivo efficacy of the manzamines against t gondii. 42 sigmosceptrellin-b isolated from the red sea sponge diacarnus erythraeanus, exhibits potent in-vitro activity against t gondii at a concentration of 0·039 g/ml without severe toxic effects. sigmosceptrellin-b is active (84-99% inhibition) against the parasite in human diploid fibroblast cells. 43 a cyclic peroxylactone, plakortide, was isolated from the jamaican sponge plakinastrella onkodes and has potent in-vitro activity against t gondii, with an ic 50 of 0·023 g/ml and no toxic effects for the host cells up to a concentration 0·12 g/ml. 44 the flagellated protozoa trypanosoma cruzi and trypanosoma brucei are, respectively, the causal agents of south american trypanosomiasis (chagas disease) and human african trypanosomiasis (sleeping sickness). the drugs used to treat these diseases, including pentamidine and suramin, require parenteral administration and are effective only against the early haemolymphatic stage of the disease. the arsenical drug melarsoprol is available for late-stage central nervous system infection, but it causes reactive encephalopathy and is difficult to administer. the nitroheterocyclic drug benznidazole, used to treat acute stages of chagas disease, is not effective against the chronic phases of the disease and is poorly tolerated, which clearly indicates the need for new drugs with structures and mechanisms of action different from those that are presently used. 45 from the green alga ulva sp the endophytic and obligate marine fungus ascochyta salicorniae was isolated and cultivated on a preparative scale, producing a structurally unusual tetramic acid metabolite ascosalipyrrolidinone a, which shows activity against t cruzi with an mic of 1·1 g/ml, whereas the control (benznidazole) has an mic of 30·0 g/ml. the main limitation for further development of this compound is its cytotoxic effects at 3·7 g/ml tested against rat skeletal muscle myoblast cells. 46 malaria is a particularly serious disease in sub-sahran africa, 47 but it is also a serious public-health issue in certain regions of southeast asia and south america. most malaria cases and deaths are caused by the parasite plasmodium falciparum. 47 since removal of the vector of transmission (the anopheles mosquito) is almost impossible, new antimalarial agents providing novel mechanisms of action will always be needed to combat resistance to drugs such as chloroquine, mefloquine, quinine, and sulfadoxine-pyrimethamine. manzamine a exhibits potent in-vitro activity against p falciparum (d6 clone), with an mic of 0·0045 g/ml, compared with control-drug (chloroquine and artemisinin) mics of 0·0155 g/ml and 0·010 g/ml, respectively. 48 manzamine a inhibits the growth of the rodent malaria parasite plasmodium berghei in vivo, with more than 90% of the asexual erythrocytic stages of p berghei inhibited after one intraperitoneal injection of 50 or 100 mol/kg manzamine a into infected mice. this treatment prolongs the survival of highly parasitaemic mice to more than 10 days compared with 2-3 days among untreated controls, 2 days among mice treated with artemisinin, and 6 days among mice treated with chloroquine; it has a 40% recovery rate 60 days after one injection. oral administration of an oil suspension of manzamine a also substantially reduces parasitaemia. interestingly, the manzamine a hydroxyl derivative (-)-8-hydroxymanzamine a, as well as the dimer neo-kauluamine, extend the lives of p berghei-infected mice far more than the two most important human therapeutic antimalarial drugs when administered as one intraperitoneal dose of 100 mol/kg. manzamine a and selected derivatives have a rapid onset of action because of high bioavailability and sustained antiparasitic activity with no apparent toxic effects. 48 manzamine a has a similar therapeutic index to chloroquine, whose toxic dose at 500 mol/kg is ten times higher than the dose required (50 mol/kg) to clear the parasite if administered three times with 2-day intervals. 48 the effectiveness of manzamine a and selected analogues against malaria makes them one of the most promising antiinfective leads to be discovered from the oceans, and understanding the structure-activity relation of this unique class of alkaloids is certain to lead to more effective and safer manzamine-related antimalarial drug leads. the previously mentioned antifungal macrolide halichondramide also has notable activity against p falciparum (d6 clone), with an ic 50 of 0·002 g/ml, which is approaching the value for the most active clinically used compounds (mefloquine 0·0003 g/ml). although halichondramide has a much lower selectivity index than currently used drugs, it represents a potential new class of compounds in the development of alternative chemotherapy for the treatment of malaria after further structure-activity relation investigations. 49 an example of a marine secondary metabolite containing the isonitrile group and eliciting significant antimalarial activity is di-isocyanoadociane, a tetracyclic diterpene with an isocycloamphilectane skeleton. di-isocyanoadociane has been isolated from the sponge cymbastela hooperi (axinellidae, halichondrida) and displayed antiplasmodial potency, with ic 50 values of 0·005 g/ml, and selectivity that rivals the invitro results obtained from clinically used antimalarial drugs (chloroquine and artemisinin). 50 the kalihinane diterpenoids exhibit several types of biological activities, of which the antimalarial activity of kalihinol a is the most noteworthy. kalihinol a was isolated from an okinawan marine sponge, acanthella sp, and it possesses notable in-vitro antimalarial activity (ec 50 0·0005 g/ml) and selectivity index (si 317) similar to those for mefloquine. 51 the development of resistance to current antibacterials continues to be a serious difficulty in the treatment of infectious diseases, and therefore the discovery and development of new antibiotics has become a high priority review anti-infectives from the sea in biomedical research. in the continuing effort by the marine natural products community, many antibacterial agents have been identified; we have focused only on those that seem to possess the greatest potential ( figure 6) . squalamine is the first aminosterol isolated from the dogfish shark squalus acanthias (squalidae). it has potent antimicrobial activity, with an mic of 1·0 g/ml against staphylococcus aureus, and antiangiogenic and antitumour properties. it is currently being tested in clinical trials for the treatment of advanced non-small-cell lung cancer. 52 cribrostatins were isolated from a blue sponge cribrochalina sp, and showed potent antineoplastic and antimicrobial activities. cribrostatin 3 has potent inhibitory activity against neisseria gonorrheae, with an mic of 0·09 g/ml. cribrostatin 3 is also active against penicillinresistant n gonorrheae (clinical isolate), with an mic of 0·39 g/ml. 53 sphaerococcus coronopifolius, a cosmopolitan red alga collected along the atlantic coast of morocco, contains the potent antibacterial diterpene, bromosphaerone. it shows antibacterial activity against s aureus, with an mic of 0·047 g/ml. 54 a marine fungus isolated from the surface of the brown alga rosenvingea sp, of the genus pestalotia, collected in the bahamas, was cocultured with a unicellular marine bacterium to yield pestalone. pestalone has potent antibiotic activity against meticillin-resistant s aureus, with an mic of 0·037 g/ml, and vancomycin-resistant enterococcus faecium, with an mic of 0·078 g/ml. these results represent an important achievement in showing that mixed fermentation can induce the biosynthesis of novel antibiotics, suggesting that this method may have use for drug discovery in the future. in addition, the potency of this agent toward drug-resistant pathogens suggests that pestalone should be assessed in more advanced animal models against infectious diseases. 55 jorumycin is a dimeric isoquinoline alkaloid that was isolated from the mantle and mucus of the pacific nudibranch jorunna funebris. it inhibits the growth of various grampositive bacteria-eg, bacillus subtilis, s aureus-at a concentration of 0·050 g/ml, with an inhibition zone of 16 mm. despite this high potency, there are several limitations for further investigation, which include its cytotoxic effects at an ic 50 of 0·012 g/ml and the difficulty in obtaining a pure stable preparation. 56 viruses have remained resistant to treatment or prophylaxis longer than any other infectious organism. the search for viral chemotherapeutic agents from marine sources has yielded several promising therapeutic leads reported to display notable antiviral activity (figure 7). perhaps the most important antiviral lead of marine origin reported thus far is the nucleoside ara-a. ara-a is a semisynthetic compound based on the arabinosyl nucleosides isolated from the sponge cryptotethia crypta. 57 once it was realised that biological systems would recognise the nucleoside base after modifications of the sugar moiety, chemists began to substitute the typical pentoses with acyclic entities or with substituted sugars, leading to the drug azidothymidine (zidovudine). ara-a (vidarabine), ara-c (1-␤-d-arabinosylcytosine; cytarabine), acyclovir, and azidothymidine are in clinical use and are all examples of products of semisynthetic modifications of the arabinosyl nucleosides. 58 the didemnins are a family of closely related cyclic depsipeptides obtained from trididemnum solidum, a caribbean tunicate, or sea squirt, of the family didemnidae. 59 in addition to their antitumour activity, they exhibit significant in-vitro and in-vivo antiviral properties. in 1982, canonico and colleagues 60 reported that didemnin b has in-vitro inhibitory effects against the viruses causing rift valley fever (ld 50 0·04 g/ml), venezuelan equine encephalomyelitis (ld 50 0·08 g/ml), and yellow fever (ld 50 0·08 g/ml). in-vivo didemnin b at a dose of 0·25 mg/kg daily in mice infected with rift valley fever virus gave a 90% survival rate. despite its important antiviral activity, didemnin b is cytotoxic and inhibits cellular dna, rna, and protein synthesis at concentrations close to those at which viral growth was inhibited, and hence it has low antiviral selectivity and therapeutic index. the didemnins might, however, be modifiable or useful in combination with other antiviral agents to combat such difficult diseases. 61 didemnin b interferes with mitogenic signal transmission such as inhibiting kinases, phosphatases, and elongation factors. since 1986, didemnin b has been subjected to phase 1 and 2 clinical trials for cancer by different groups, and the consensus is that with the dose schedules used, the drugs provided little efficacy and substantial toxic effects. 61 eudistomins represent a large family of ␤-carboline alkaloids that have been isolated from shallowwater tunicates from the genus eudistoma. there are four types of eudistomins, including: unsubstituted, pyrrolyl-substituted, pyrrolinyl-substituted, and tetrahydro-␤-carbolines containing a uniquely condensed oxathiazepine ring system. the in-vitro antiviral potency of the eudistomins against herpes simplex viruses 1 and 2 ranges from 5 ng/disk to 500 ng/disk and follows a trend in which the oxathiazepino-tetrahydro-␤-carbolines show greater potency than 1-pyrrolinyl-substituted, which in turn have better antiviral activity than the 1-pyrrolyl-substituted compounds. 62 perry and colleagues 63 reported isolating and investigating the structure of mycalamide a from a new zealand sponge mycale sp. they found that a material consisting of 2% mycalamide a was effective against a59 coronavirus in vivo in mice at 0·2 g/kg daily, with 100% survival after 14 days. when pure mycalamide a has been obtained, it inhibited herpes simplex virus 1 and poliovirus type 1 at 0·005 g/disk. 63 when mycalamide b was isolated, it showed greater antiviral activity and cytotoxicity than mycalamide a. in-vitro antiviral testing showed a minimum dose of inhibition of 0·001-0·002 g/disk for mycalamide b. mycalamide a and b are protein synthesis inhibitors. 64 further antiviral marine natural products are presented in table 2. the unprecedented diversity of marine natural products combined with an improved global awareness about the need for new anti-infective treatments is certain to result in an increased effort to move the product of the marine environment into clinical applications. although marineproduct leads have historically been confronted with many obstacles, including a sustainable supply-ie, the compounds may account for less than 10 -6 % of the wet weight 73 -there have been substantial advances, which suggest that sustainable sourcing will be achievable. we have learned from terrestrial drug leads that continuous and exhaustive harvesting from nature is not reliable and puts the respective species under risk of extinction. consequently, the large-scale production of metabolites from marine natural products for clinical applications is a real challenge and alternative strategies for environmentally sound and economically feasible supplies are clearly needed. traditionally, among the first options to be explored for the supply of marine-derived small molecules is chemical synthesis. unfortunately, the structural complexity of marine molecules, which suggests novel mechanisms of action and high selectivity, has also resulted in few economically feasible strategies for total chemical synthesis. one successful example of the synthetic production of a marine-product drug in unlimited quantities is the conus toxin ziconotide, because of its peptide nature. 74 a second but also fairly labour-intensive strategy is to do studies of the biological roles of marine natural product pharmacophores, with a clearly defined structural moiety, and attempt to define whether the critical pharmacophore via synthesis, chemical degradation, modification, or a combination of these, can result in more practical drugs based on a marine prototype. the aquaculture of the source organisms, including sponges, tunicates, and bryozoans, with the aim of securing a steady supply of drug product, has progressed notably in cancer applications, although in most cases the biomass currently generated is still far short of those required should a marine-based drug finally enter the market. 75 furthermore, the cultivation of invertebrates in their natural environment is subject to several uncertainties, such as destruction by storms or disease. an intriguing strategy has been to identify the true producers of bioactive compounds to find out whether or not they are of microbial origin, based on the fact that most if not all of the marine invertebrates harbour large communities of microorganisms, including bacteria, cyanobacteria, and fungi within their tissues. 76 many studies have successfully provided data to support the involvement of microorganisms in the biosynthesis of natural products isolated from invertebrates. the major breakthrough in the characterisation of the microbial communities associated with sponges involve the application of molecular methods such as fluorescence in-situ hybridisation, with the use of group-specific 16 s rrna-targeted oligonucleotide probes. this approach has led to the identification of the bacterial communities associated with many marine invertebrates. 77 review anti-infectives from the sea if bacteria or other associated microorganisms do produce these compounds of interest, the careful design of special media for culture would be useful for large-scale fermentation. currently, only an estimated 5% or less of the bacteria seen in marine samples by microscopic methods can be cultivated under standard conditions. 78 as a result, molecular approaches offer particularly promising alternatives through the transfer of biosynthetic gene clusters to a vector suitable for large-scale fermentation, thereby avoiding the difficulties in culturing symbiotic bacteria. clearly, the world's oceans will play an important part in the future control of the global infectious-disease burden. although substantial progress has been made in identifying novel drug leads from the ocean's resources, great efforts are still needed to advance to clinical applications. none declared. a 56-year-old man presented to the emergency department with a 4-week history of a painful left-sided preparotid swelling. computed tomography suggested that the lesion was most likely a tuberculous abscess (figure). samples for a clinical armamentarium of marinederived anti-cancer compounds the bioprocess-technological potential of the sea marine and freshwater products handbook biological activities of selected marine natural products marine natural products et-743 natural products as potential antiparasitic drugs secondary metabolites with antinematodal activity marine natural products as antituberculosis agents natural products as antiviral agents antifungal metabolites from marine sponges marine bioprospecting: trawling for treasure and pleasure the influence of natural products upon drug discovery marine natural products jasplakinolide a cyclodepsipeptide from the marine sponge jaspis sp gambieric acids: new potent antifungal substances with unprecedented polyether structures from a marine dinoflagellate gambierdiscus toxicus aurantosides d e and f: new antifungal tetramic acid glycosides from the marine sponge siliquariaspongia japonica phorboxazoles a and b: potent cytostatic macrolides from marine sponge phorbas sp halishigamides a-d new cytotoxic oxazolecontaining metabolites from okinawan sponge halichondria sp macrocyclic antifungal metabolites from the spanish dancer nudibranch hexabranchus sanguineus and sponges of the genus halichondria fascaplysin: an unusual antimicrobial pigment from the marine sponge fascaplysinopsis sp antifungal activity of meridine a natural product from the marine sponge corticium sp bengazoles c-g from the sponge jaspis sp synthesis of the side chain and determination of absolute configuration ptilomycalin a: a novel polycyclic guanidine alkaloid of marine origin haliclonadiamine: an antimicrobial alkaloid from the sponge haliclona sp 8-hydroxymanzamine a a ␤-carboline alkaloid from a sponge pachypellina sp 1234-oxamanzamines novel biocatalytic and natural products from manzamine producing indo-pacific sponges assessment of antimycobacterial activity of a series of mainly marine derived natural products novel antimycobacterial benzoxazole alkaloids from the west indian sea whip pseudopterogorgia elisabethae serrulatane diterpenes with antimycobacterial activity isolated from the west indian sea whip pseudopterogorgia elisabethae novel 19-oxygenated sterols from the okinawan soft coral litophyton viridis puupehenone-related metabolites from two hawaiian sponges hyrtios spp nutritional impact of intestinal helminthiasis during the human life cycle marine nematodes: tetrahydrofurans from a southern australian brown alga notheia anomala amphilactams a-d: novel nematocides from southern australian marine sponges of the genus amphimedon geodin a magnesium salt: a novel nematocide from a southern australian marine sponge chemotherapy of leishmaniasis: recent advances in the treatment of visceral disease leishmania and human immunodeficiency virus coinfection: the first 10 years antileishmanial cyclic peroxides from the palauan sponge plakortis aff angulospiculatus toxoplasmosis in aids patients anti-toxoplasmosis drugs new manzamine alkaloids with potent activity against infectious diseases antimalarial antiviral and antitoxoplasmosis norsesterterpene peroxide acids from the red sea sponge diacarnus erythraeanus new peroxylactones from the jamaican sponge plakinastrella onkodes with inhibitory activity against the aids opportunistic parasitic infection toxoplasma gondii recent advances in identifying and validating drug targets in trypanosomes and leishmanias ascosalipyrrolidinone a: an antimicrobial alkaloid from the obligate marine fungus ascochyta salicorniae survey of malaria treatment and deaths in vivo antimalarial activity of the betacarboline alkaloid manzamine a the marine environment: a resource for prototype antimalarial agents novel potent antimalarial diterpene isocyanates isothiocyanates and isonitriles from the tropical marine sponge cymbastela hooperi antimalarial activity of kalihinol a and new relative diterpenoids from the okinawan sponge acanthella sp aminosterols from the dogfish shark squalus acanthias antineoplastic agents 430 isolation and structure of cribrostatins 3 4 and 5 from the republic of maldives cribrochalina sp marine lit, and references from relevant articles. search terms were "antifungal marine new bromoditerpenes from the red alga sphaerococcus coronopifolius pestalone a new antibiotic produced by a marine fungus in response to bacterial challenge a new antitumor isoquinoline alkaloid from the marine nudibranch jorunna funebris contributions to the study of marine products: the nucleosides of sponges new anti-hiv agents and targets structures of the didemnins antiviral and cytotoxic depsipeptides from a caribbean tunicate inhibition of rna viruses in vitro and in rift valley fever-infected mice by didemnins a and b natural products as probes of cell biology: 20 years of didemnin research eudistomins c e k and l potent antiviral compounds containing a novel oxathiazepine ring from the caribbean tunicate eudistoma olivaceum mycalamide a an antiviral compound from a new zealand sponge of the genus mycale antiviral and antitumor agents from a new zealand sponge mycale sp 2: structures and solution conformations of mycalamides a and b papuamides a-d hiv-inhibitory and cytotoxic depsipeptides from the sponges theonella mirabilis and theonella swinhoei collected in papua new guinea inhibition of replication of the etiologic agent of acquired immune deficiency syndrome (human t-lymphotropic retrovirus/ lymphadenopathy-associated virus) by avarol and avarone debitus c: in vitro antiviral activity on dengue virus of marine natural products microspinosamide a new hiv-inhibitory cyclic depsipeptide from the marine sponge sidonops microspinosa solenolides new antiinflammatory and antiviral diterpenoids from a marine octocoral of the genus solenopodium hennoxazoles bioactive bisoxazoles from a marine sponge venustatriol a new anti-viral triterpenes tetracyclic ether from laurencia venusta antitumor and antiviral furanoditerpenoids from a marine sponge drugs from the seas: current status and microbiological implications mviia: from marine snail venom to analgesic drug aquacultural production of bryostatin 1 and ecteinascidin 743 electron microscope study of the association between some sponges and bacteria microbial diversity in the marine sponge aplysina cavernicola analyzed by fluorescence in situ hybridization (fish) chemical studies of marine bacteria: developing a new resource review anti-infectives from the sea the preparation of this review was supported by nih grants r01ai 36596 and ko2ai01502 from the national institute of allergy and infectious diseases, and the egyptian government (predoctoral fellowship for md). we thank charles stanley for his assistance in the preparation of this review. anti-infectives from the sea rabbit's revenge analysis were obtained from incision and drainage of the abscess; however, no acid-fast bacilli could be detected and culture media for bacteria, fungi, and mycobacteria remained without growth. a few days after his admission, the patient's wife joined her husband with a painful cervical lymph node. on further investigation it emerged that the couple had eaten a medium roasted wild rabbit in a berlin restaurant 2 months earlier. 1 week after the meal they both developed an exudative pharyngitis. oropharyngeal tularaemia was suspected and confirmed for both patients by positive serology. they both received a 2-week course of streptomycin and recovered uneventfully.tularaemia is caused by the gram-negative rod francisella tularensis. natural reservoirs and vectors include several small mammals, as well as insects like ticks and mosquitoes. transmission to people is through direct contact with infected animals, inhalation of contaminated fomites, insect bites, and ingestion of contaminated food. the primary clinical presentation of tularaemia depends on the site of entry of the bacterium into the body. oropharyngeal tularaemia results from oral exposure from contaminated fluids or foods. key: cord-315918-12rbbe8c authors: mukherjee, pulok k. title: antiviral evaluation of herbal drugs date: 2019-06-21 journal: quality control and evaluation of herbal drugs doi: 10.1016/b978-0-12-813374-3.00016-8 sha: doc_id: 315918 cord_uid: 12rbbe8c the viral infection and resistance to the existing antiviral drugs are alarming, which is a serious public health concern. medicinal plants are valuable resources for treatment of viral infections and can be used for the management of infections like herpes simplex virus (hsv), human immunodeficiency virus (hiv), influenza, etc. the antiviral screening of plant extracts should be highly selective, specific, and sensitive for bioactivity guided isolation of the active compounds from the plant extracts. the antiviral screening system should be validated for accuracy, reproducibility, simplicity, and cost effectiveness. this chapter highlights on various aspects for screening and evaluation of antiviral natural components including factors affecting antiviral in vivo studies, host cells, organisms, and culture media followed by different virus-specific assays for antiviral screening of natural products. although vaccines have been very successful in controlling many viral diseases, some diseases are likely to be controlled only by antiviral chemotherapy. the concept of antiviral drugs has only been accepted slowly, partly because of the toxicity of many of the earlier antiviral agents. in contrast to the development of antibiotics, attempts to develop antiviral drugs have indeed met a variety of problems. being strictly dependent on cellular metabolic processes, viruses possess only limited intrinsic enzyme systems and building blocks that may serve as specific targets for a drug. moreover, contrary to a bacteriostatic compound, an effective antiviral drug should not only display considerable specificity in its antiviral action, but should also irreversibly block viral synthesis in order to stop cell suicide due to the viral infection and restore normal cell synthesis (vanden berghe et al., 1986) . in addition to this inhibition, the antiviral agent must have a broad spectrum of activity, favorable pharmacodynamic properties, and not be immunosuppressive. in the ideal situation, the antiviral drug checks the infection while the immune system prepares to destroy the last virus particles (munro et al., 1987) . this point is critical for those immune-compromised by illness (aids, cancer) or drug therapy (transplants, cancer). a frequent cause of death in these instances is from viral infections, so that adjuvant antiviral chemotherapy is vital in these circumstances (shannon and schabel, 1980) . many viral infectious diseases still cause high mortality. although antiviral chemotherapy has shown outstanding progress, antiviral agents are still required. the emergence of drug-resistant viruses during treatment raises a potential problem for effective therapy. furthermore, new viral pathogens may be discovered. biologically active substances of plant origin have long been known as viral inhibitors. these antiviral compounds may be extracted from sources, such as higher plants, which have, for various reasons, been explored considerably less than the traditional ones. the first clinically useful antiviral drug was methylisatin-thiosemicarbazone (methisazone), which was active against pox viruses, especially smallpox virus. methisazone (25 mg/kg) was found to inhibit variola virus in mice and was later used successfully to treat cases of eczema vaccinatum and to treat and prevent smallpox. kaufman et al. (1962) , an ophthalmologist, successfully treated a herpes eye infection with an antineoplastic drug, idoxuridine. at the same time, a group of chemists at the du pont chemical company in the united states investigated the antiviral activity of a molecule called amantadine. it was active against influenza virus type a. in rapid succession, further nucleoside analogs, cytosine arabinoside, trifluorothymidine, and adenine arabinoside, were found to inhibit herpes virus. in the 1970s, the antiherpes activity of a new compound, 9-(2-hydroxyethoxymethyl) guanine (acyclovir), was detected by j. bauer at the wellcome research labs. within a decade, the same group was to discover azidothymidine (zidovudine), the first effective inhibitor of the newly emerged hiv. the alkaloid from the australian horse chestnut (castanospermine australe), isolated in the 1980s, was also found to be active against hiv. a research program to detect and isolate antiviral compounds from higher plants is best carried out by a multidisciplinary team, consisting of at least a pharmacognosist and a virologist. the antiviral screening system should meet all requirements of any good assay, including validity, lack of ambiguity, accuracy, reproducibility, simplicity, and reasonable cost. moreover, because we are dealing with plant extracts, the antiviral screen should be highly selective, specific, and sensitive; it is advisable to discriminate a true antiviral activity from a viricidal one at this stage. because most of the aforementioned requirements are better met by in vitro testing, we not only prefer in vitro screening of the plant extracts, but also the use of the same bioassay to guide the isolation of the antivirally active compounds from the plant extracts. the antiviral activity of the pure compounds then has to be confirmed in a later stage by in vivo assays (leven et al., 1982; vanden berghe et al., 1986) . one of the possible strategies for finding new antiinfective drugs may involve the search for compounds with chemotherapeutic activities supplementary to, and structures widely different from, those in current use. these compounds could be extracted from sources that have, for various reasons, been explored considerably less than the traditional microorganisms, including, among others, higher plants (mitscher and rao, 1984) . considering the enormous number and the amazing structural diversity of the currently available antimicrobially and antivirally active plant constituents, one might hope that promising systemic and/or locally acting antiinfective agents might be discovered in the plant kingdom (vanden berghe et al., 1986; vlientinck et al., 1988) . the increase of drug-resistant viruses in treatment raises an important issue for effective treatment. moreover, new viral pathogens might be found. along these lines, there is a strong requirement for promptly accessible antiviral medications at moderate costs with minimal side effects. henceforth, traditional medicines ought to be investigated as novel antiviral agents, as many of these ancient medicaments, containing different plant metabolites, have potent antiviral activities (chattopadhyay and khan, 2008) . the design of new antiviral drugs potentially focuses on the structural dynamics and replication cycles of the various infections causing viruses. a suitable example is the invention of acyclovir, which hinders certain proteins of herpes infections responsible for the triggering of disease. ethnomedicines are a vast repository of structural diversities and extensive bioactivities that can serve as a huge source of potential antiviral drugs. a significant number of medicinal plants from ayurveda and the traditional chinese system of medicine serve as potential remedies to decrease the severity of illness caused by viruses (chattopadhyay et al., 2009; khan et al., 2005; jadhav et al., 2012) . research on the antiviral potentials of plants was first started in 1952, and 12 out of 288 plants were found to be effective against influenza (chattopadhyay and naik, 2007) . numerous screening studies have been conducted in the last few years to determine the antiviral efficacy of medicinal plants using in vitro and in vivo assays. a few out of a 100 british colombian medicinal plants showed antiviral efficacy against respiratory syncytial virus (rsv), corona virus, influenza virus, and herpes simplex virus (hsv) (mccutcheon et al., 1995) , while the marine algae spirulina showed antimutagenic, immunomodulatory, and antiviral activities (chamorro et al., 1996) . interestingly, cyanovirin n, an 11-kda protein of blue green algae, inactivates hiv-1 by binding with its glycoprotein120 (clercq , while sulfated polysaccharides of seaweeds and algae showed anti-hiv and anti-hsv activities (schaeffer and krylov, 2000) . the plant kingdom is highly diverse and ranges from unicellular microscopic plants to long lived, huge trees. to screen each and every plant or their individual parts for the identification of antiviral components is a huge task. several examples of plants having antiviral properties and newly identified active compounds from them are reported in various journals. one of the examples that can be cited here is cyanovirin n (cv-n), an 11-kda protein isolated from the cyanobacterium nostoc ellipsosporum, which exhibits the property of inhibiting hiv-1 infection and also possesses broad-spectrum activity. the phytochemical, podophyllotoxin, isolated from the aqueous extract of podophyllum peltatum l., inhibited hsv type 1 (hsv-1) (bedows and hatfield, 1982) . the acetone extract of another plant, phyllanthus urinaria, also suppressed hsv-2 and hsv-1 (yang et al., 2007) . bessong et al. (2006) reported a comparison of various plants and their individual parts (stem, leaves, roots, and so forth.) in repressing viral reverse transcriptase (rt) and integrase, the two basic enzymes in hiv disease. after comparing all the extracts and fractions of the various plants, it was found that the n-butanol fraction of bridelia micrantha (hochst) exhibited the highest anti-rt activity. it has also been reported that the aqueous extract from the roots of carissa edulis (forssk.) vahl, a plant grown in kenya, displayed noteworthy activity against hsv for both wild type and resistant strains (tolo et al., 2006) . polyphenol-rich extract from the medicinal plant geranium sanguineum l. has been reported to show a strong antiinfluenza virus activity, as well as antioxidant and radical scavenging capacities (sokmen et al., 2005) hepatitis a, b, c, d, and e viruses are the leading causes for the prevalence of viral hepatitis and liver inflammation. despite the fact that presentation to any of these infections prompts intense disease, in any case, types b, c, and d are unique in causing chronic infection. plants belonging to the genus phyllanthus of the euphorbiaceae family were extensively used as a traditional remedy against these infections. clinical investigations were additionally intended to look at the inhibitory effects of different species of phyllanthus, that is, p. amarus (l.), p. niruri (l.), and p. urinaria (l.) (wang et al., 1995) . the screening of 56 different chinese medicinal herbs led to the identification of two potent plant extracts against duck hepatitis b virus, namely, ardisia chinensis and pithecellobium clypearia . similarly, this also led to the identification of oenanthe javanica (blume) dc flavones (ojf). they acted as a strong inhibitor of hbsag and hbeag secretion (involved in viral pathogenesis) in 2.2.15 cells and also reduced dhbv-dna levels in the hbv-infected duck model (wang et al., 2005) . because of the strong prevalence of hcv infection in poor countries, screening for the identification of anti-hcv potentials from medicinal plants are still ongoing. according to hussein et al. (2000) various plant extracts, such as methanol extracts acacia nilotica l. willd ex delile, boswellia carterii, embelia schimperi, quercus infectoria, trachyspermum ammi l., and aqueous extracts of piper cubeba l., q. infectoria, and syzygium aromaticum l., were found to possess significant inhibitory activity against hsv. combination therapy for treating diseases is an age-old practice of traditional medicine in which several plants are mixed together to develop an effective formulation for a particular disease. such combination therapies have also been tried for the inhibition of viral hepatitis. as an example, a chinese herbal medicine, prepared by liquid fermentation broth of ganoderma lucidum supplemented with an aqueous extract of radix sophorae flavescentis, was potent against hepatitis b virus activity in vitro and in vivo. viral infections are a matter of great concern for this planet. plants having broad-spectrum activity against many viruses could be evaluated for isolation and identification of molecules for treating viral infections. as an example, glycyrrhizin, a bioactive component of licorice (glycyrrhiza uralensis fisch), and lycorine, isolated from lycoris radiata l., showed strong anti-sars-cov activity, and was initially used for treating other indications (li et al., 2005a, b) . a variety of herbal preparations have shown potentials for inhibiting viruses that cause serious infections among humans, such as measles viruses (olila et al., 2002) , human rotaviruses (hrv) (husson et al., 1994; takahashi et al., 2001) , respiratory syncytial virus (rsv), human rhinoviruses (glatthaar-saalmuller et al., 2001) , the coxsackie group of viruses (evstropov et al., 2004; su et al., 2006) , neurotropic sindbis virus (nsv) (paredes et al., 2001) , and various strains of polio virus (andrighetti-frohner et al., 2005; melo et al., 2008) . one such illustration is the atomic investigation of the heated water concentrates of stevia rebaudiana l., which blocked a section of different irresistible serotypes of hrv into permissive cells by an anionic polysaccharide having a molecular weight of 9800 with uronic acid as a noteworthy sugar constituent (takahashi et al., 2001) . thus, an alkaloid concentrate of haemanthus albiflos globules repressed rna amalgamation of hrv spread in ma-104 cells (husson et al., 1994) . in contrast to the many publications on antibacterial and antifungal screening of plant extracts that have appeared in the last decades, far fewer antiviral screening studies of plant extracts have been reported. this is due chiefly to the complexity of the different techniques involved in such research, which consequently requires the know-how and dedication of a multidisciplinary team. nevertheless, many antiviral agents have been isolated from natural sources and partly or completely characterized. from these studies, several substances have emerged as true antivirals having a good chemotherapeutic index based on the viability of infected cells and on in vivo tests. thus, different 3-methoxy flavones and synthetic derivatives have shown to be promising leads for the development of antirhinovirus drugs (van hoof et al., 1984; vlientinck et al., 1988) , whereas the spanonin, glycyrrhizic acid, was found to be highly active in vitro against herpes simplex (pompei et al., 1979) , varizella-zoster (baba and shijeta, 1987) , and human immunodeficiency viruses (ito et al., 1987) . whether these compounds have any clinical potential, that is, in the therapy of the corresponding viral diseases, remains to be determined. there, in vivo bioavailability and other pharmacokinetic parameters are subjects of future study. because of the problems of drug resistance stated earlier and of side effects, the pharmaceutical industry is looking forward toward natural products (mainly medicinal plant extracts) as a source of possible antiviral agents. approximately 2500 medicinal plant species have been recorded globally to treat a myriad of inflictions and diseases. polyphenols, alkaloids, flavonoids, saponins, quinones, terpenes, proanthocyanidins, lignins, tannins, polysaccharides, steroids, thiosulfonates, and coumarins are prominent bioactive phytochemicals that have been observed to combat viral infections, as they are harmless to the systems of the human body. some selected anthraquinones and anthraquinone derivatives are noted for their dammarane saponins, ginsenoside rb1 (grb1), and chikusetsusaponin (chi-iii) have been found to possess antiviral activity against hsv-i using an in vitro plaque elimination assay. chi-iii prevented plaque formation at half the concentration of grb1 (fukushima et al., 1995 (hudson and towers, 1995) . the inhibitory effect of ferulic acid and isoferulic acid on murine interleukin-8 production in response to influenza virus infections in vitro has been reported (hirabayashi et al., 1995) and the effect of isoferulic acid was found to be greater than that of ferulic acid. hayashi et al. (1995) found a direct inhibitory activity of the steam distillate prepared from fresh plants of houttuynia cordata (saururaceae) against hsv-1, influenza virus, and hiv-1, without showing cytotoxicity, but not against poliovirus and coxsackie virus. montanha et al. (1995a) evaluated the action of a series of 19 aporphine alkaloids against hsv-1 in cell cultures. on the basis of viral titer reduction, six alkaloids were found to be active. ellagitannins isolated from phyllanthus myrtifolius and p. urinaria (euphorbiaceae) showed activity against epstein-barr virus dna polymerase. flavonoidal constituents, such as biflavonoids and robustaflavones, exhibited strong inhibitory effects against influenza a and b viruses. the antiviral potential of the flavonoids of chamaesyce thymifolia has been reported; they showed high cytotoxicity on hep-2 cells and moderate inhibitory activity against hsv-1 and bovine viral diarrhea virus (amaral et al., 1999) . sotanaphun et al. (1999) isolated sclerocarpic acid from the stem bark of glyptopetalum sclerocarpum, which exhibited antiviral activity against herpes simplex virus types 1 and 2. rhamnan sulfate, a natural sulfated polysaccharide isolated from monostroma latissimum, showed potent inhibitory effects on the virus replication of hsv-1, hcmv, and hiv-1 in vitro . matsuse et al. (1999) tested aqueous and methanolic extracts of 39 panamanian medicinal plants for anti-hiv effects. seven of these were found to be moderate inhibitors of hiv-protease enzyme. serkedjieva and ivancheva (1999) investigated the inhibitory effect of five extracts from the bulgarian medicinal plant g. sanguineum on herpes simplex virus types 1 and 2. yoosook et al. (1999) evaluated the anti-hsv-2 activities of barleria lupulina and clinacanthus nutans. the results suggested a therapeutic potential against hsv-2 for b. lupulina, but not for c. nutans. the antiviral activities of various water and methanol soluble substances isolated from g. lucidum against hsv types 1 and 2, influenza a virus, and vesicular stomatitis virus were studied using cytopathic effect inhibition assay and plaque reduction assay (eo et al., 1999) . kudi and myint (1999) investigated the antiviral activity of medicinal plant extracts against poliovirus, astrovirus, hsv, and parvovirus. most of the extracts showed activity against more than one virus at a dose rate of between 100 and 400 î¼g/100 î¼l (eo et al., 1999) . bourne et al. (1999) assessed 19 plant products in vitro by plaque reduction assay to determine their activity against a commonly transmitted pathogen, herpes simplex virus type 2. docherty et al. (1999) found that resveratrol, a phytoalexin, inhibited hsv-1 and hsv-2 replication in a dose-dependent reversible manner. anani et al. (2000) prepared methanol extracts from 19 medicinal plants of togo and analyzed them for antiviral and antibiotic activities. ten of the 19 showed significant antiviral activity against one or another of the test viruses (herpes simplex, sindbis, and poliovirus). hudson et al. (2000a, b) evaluated ethanolic extracts of 11 plants, endemic to madagascar, in order to determine the potential of malagasy plants as sources of antiviral activities. nine of the extracts had significant activity against hsv, whereas only four were active against the sindbis virus. a bioactive flavonoid, "baicalein," isolated from the chinese medicinal plant scutellaria baicalensis georgi showed antiviral properties using the high-speed countercurrent chromatography (hsccc) technique (li and chen, 2005) . many other substances, including flavonoids, phenolics, tannins, triterpenes, and alkaloids, interfere with host cell replication at their antivirally active concentrations or only exhibit extracellular viricidal activities. some of these viricides, including flavonoids and tannins present in foodstuffs, might be important, because they can inhibit virus replication of picorna-, rota-, and arena viruses in the gastrointestinal tract of humans and animals. artemisia capillaris was found to possess an active 6,7-dimethylesculetine having potent cytotoxic potential. in the fruits of schisandra chinensis (schizandraceae) used in oriental medicine, 22 lignans were identified, some of which, such as wuweizisu c and gomisine n, are very active. the same method threw light on the mechanism of the antihepatotoxic action of such well-known compounds as glycyrrhizin and its intestinal metabolites, which are protective against the first stages preceding hepatic lesions. other tests of this type are used to track down active substances. from taxus baccata, potier's group isolated new analogs of taxol, a terpenic compound displaying very good antileukemic and antitumor activities. taxol promotes the polymerization of tubulin into microtubules and inhibits their depolymerization. the choice among various fractions obtained by extraction was guided by the antitubulin activity in an in vitro test. many substances that are present in only trace quantities and are difficult to purify have been studied chemically; for example, the demonstration of xylose-bearing derivatives is new in this series of compounds. regarding structure activity relationships, in vitro cytotoxicity tests have shown that the activity is mainly related to the presence of a complex ester function in the compound. a list of plant extracts and their phytoconstituents that have antiviral potentials are listed in table 16 .1. in recent years, a lot of development has taken place regarding the identification of antiviral molecules from plant sources and the molecular mechanistic approach. compounds, such as spiroketalenol ether derivatives isolated from rhizome extract of tanacetum vulgare, have been reported to block virus entry and also arrest the synthesis of hsv-1 gc and hsv-2 gg glycoproteins (fernandes et al., 2012) . samarangenin b from the roots of limonium sinense exhibited inhibition of hsv-1î± gene expression (kuo et al., 2002) , whereas oxyresveratrol from artocarpus lakoocha plant was found to inhibit the early and late phases of viral replication of hsv-1 and hsv-2, respectively (chuanasa et al., 2008) . also, pterocarnin a compound isolated from pterocarya stenoptera inhibited hsv-2 from binding and penetrating to the host cells (cos et al., 2003) . the structures of some of the potential phytoconstituents having significant antiviral activity are depicted in fig. 16 .1. many of the antiviral drugs now known have been discovered by random search in the laboratory. most labs use a biological test system in which new molecules are added to tissue culture cells at a range of concentrations (e.g., 100-1000 î¼g/ ml); the drug-treated cells (and untreated cells as control) are then infected with a known multiplicity of infective virus particles. thousands of compounds can inhibit viral replication in a cell culture. in general, the more complex the regulatory mechanisms of a virus, the easier it is to find molecules that inhibit it. a broad estimate of the ratios of the activity of antiviral compounds in a cell culture, animal models, and humans is 1000:10:1. during the evaluation of antiviral agents, many test conditions, such as the cell culture system, virus strain, virus challenge dose, virus input multiplicity of infection, and time of harvesting, can affect or even alter the test results. to test the inhibitory activity of a new antiviral agent, it is first necessary to select the host cell system(s) in which the virus replication can be measured. viruses vary considerably in their ability to replicate in cultured cells. many viruses can cause cpe while some of them can form plaques. others can produce some specialized functions, such as hemagglutination, hemadsorption, or cell transformation. virus replication in cell cultures can also be detected by the presence of viral products, namely, viral dna, rna, or polypeptides. the antiviral tests selected may be based on: (a) inhibition of the virus-induced cytopathic effect (cpe) in which the 50% effective dose (ed 50 ) of the antiviral agent is expressed as the concentration that inhibits cpe in half of the quadruplicate cultures. (b) plaque reduction assay in which the dose of the drug required to reduce the plaque number by 50%, that is, ed 50 is calculated. (c) virus yield reduction assay in which the drug concentration required to reduce 90% (1 log 10 reduction), or 99% (2 log 10 reduction) of the virus yield as compared with the virus control (infected cultures without drug) are determined from the dose-response curves and are expressed as ed 90 or ed 99 of the antiviral agent. (d) assay systems based on the measurement of specialized functions and viral products; a number of viruses do not produce plaques nor do they cause cpe readily, but they may be quantified by certain specialized functions based on their unique properties, for example, hemagglutination and hemadsorption tests used to study the antiviral activity against myxoviruses and elisa, used to determine the extent of virus replication and, thus, obtain a measure of the inhibitory effect of various antiviral agents on virus replication, etc. (hu and hsiung, 1989 ). colorimetric assays quantify cell viability through enzyme-mediated biochemical reactions owing to ingress of certain dyes inside living cells. mosmann, borenfreund, and puerner first advocated the application of tetrazolium (mtt) and neutral red (nr) assay, respectively, to quantitate cell viability and the cytotoxicity to cells in vitro. parida et al. (1999) compared the efficacy of two colorimetric assays (mtt and neutral red) to determine viral infectivity in microculture virus titration employing polio virus type-3 and dengue virus type-4. mtt assay, also known as tetrazolium assay, has been exploited extensively to reveal the protective efficacy of therapeutic agents and plant extracts against cancer, hiv-1, hsv, polio virus type 3, den-4 virus, and to the determination of neutralizing antibody levels to hiv and respiratory syncytial virus. mtt assay using microculture virus titration (mcvt) was applied for the determination of infectivity titers of influenza viruses and was found to be compatible with the well-established procedure of egg infectivity assay. unlike mtt, neutral red dye uptake assay has not been substantially exploited in virologic research. nr dye assay was earlier performed for the study of the antiviral efficacy of basil leaves extract against polio virus type 3. mtt, a tetrazolium salt, is a yellow-colored dye [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] which gets cleared by mitochondrial succinate dehydrogenase enzyme into a blue-colored formazan in active cells. this product does not form crystals when it interacts with isopropyl alcohol and thus can be accurately measured. there is no need to harvest the viable cells, wherein the cell viability can be directly measured by a spectrophotometer (parida et al., 1999) . the assay procedure has been discussed in section 16.6.7. a colorimetric assay based on the cleavage of the tetrazolium salt wst-1 has been developed for human cytomegalovirus (hcmv) antiviral susceptibility testing and adapted to a microtiter plate format. bedard et al. (1999) developed a colorimetric assay based on the cleavage of the tetrazolium salt wst-1 for human cytomegalovirus antiviral susceptibility testing. the response of different cell cultures to a given antiviral agent, including the drug metabolism and toxicity, among other factors, may vary greatly. to perform antiviral testing against a particular virus infection, it is necessary to obtain a suitable host cell system for that virus infection. the same antiviral agent may behave very differently in different cell culture systems, although the same virus strain is used. (ii) virus strain and passage history the variability of sensitivity to a given antiviral agent has been noted among different strains of hsv and cmv. drugresistant strains have emerged to some antiviral agents, especially in the herpes virus group. the passage history of a virus strain may also affect its sensitivity to some antiviral agents. moi can influence substantially the evaluation of antiviral activity by the plaque reduction method or the virus yield reduction assay. high moi will decrease the sensitivity of the virus to an antiviral agent. this may also contribute to the disparity among antiviral evaluation results, even when the virus moi is kept constant (hu and hsiung, 1989) . ( the activities of several known antiviral phytochemicals are profoundly affected by the presence of serum components. for example, the terthiophene, î±-terthienyl (î±-t) was inhibited in a concentration-dependent manner by serum. in the case of the carboxylic acid derivative of î±-t, the compound appeared to have no antiviral activity at all in the presence of serum, yet in its absence this compound was as effective as î±-t. in contrast, the complex anthraquinone hypericin required a small amount of serum for maximal antiviral activity. the reactions were also strongly affected by the order of incubation of the components: virus, compound, serum, and light (hudson and towers, 1995) . the viruses to be selected for initial evaluation of plant extracts are obviously of major importance. they must be chosen to represent the different groups of viruses according to their morphology and various multiplication mechanisms and a range of virus diseases for which chemical control would be useful. besides the need for control, also the prevalence of the viral diseases and the resulting projection of the market potential, which are determined by the antigenic abundance of the causative viruses and the problems this represents for vaccine control, are important selection criteria (grunert, 1979) . in vitro methods are therefore more appropriate, because they allow simultaneous screening of a battery of viruses. in vivo screening of extracts against a broad array of viruses, in contrast, is not only very expensive but also extremely laborious. in vitro antiviral bioassays utilize thinly confluent monolayers of tissue culture cells with sufficient susceptibility to the infecting viruses that a visibly cytopathogenic effect (cpe) occurs, for example, rounding up. shrinking or detaching of cells from the monolayer can be produced and readily observed microscopically. a monolayer of cells consists of animal or human cells, such as chick embryo, rabbit, or green monkey kidney cells (vero cells), or human skin fibroblasts and carcinoma cells (hela cells), grown in a culture medium. such continuous cell lines used in virology are mostly "transformed" cells that can be maintained for an indefinite number of generations. the host cells require an appropriate tissue culture medium in which they can survive for at least 1 week without having to renew the medium. renewal of the medium causes changes in intra-and extracellular products and alters the virus concentration. the medium must have a stable ph during the whole incubation time and may contain only a small amount of serum, because blood products tend to absorb many compounds. mostly, a defined synthetic medium, supplemented by some type of serum (such as fetal bovine, calf, or horse), a buffer on sometimes bacterial and fungal inhibitory antibiotics, is used. according to experience, vero cells, which allow the growth of many human viruses with visible cpe, grown in the medium described by hronovosky et al. (1975) , and slightly modified by lowering the pyruvate concentration, are most suitable for antiviral screening of plant extracts (van den berghe et al., 1978) . many combinations of test viruses are possible, but a battery of six viruses seems to be quite acceptable. virus types and strains may vary in sensitivity, but have to be selected as a function of their ability to multiply in the same tissue culture when cell culture models are used as screening systems. in this way, an objective comparison of antiviral activities is possible, whereas toxicity tests are minimized. moreover, virus multiplication must cause a visible cpe within a reasonable period of time, preferably within a week after infection. which are expressed as the number of infectious units per volume. an infectious unit is defined as the smallest amount of virus capable of producing a reaction after virus inoculation and can be carried out by two generally applied methods, namely, the plaque test (pt) and the 50% endpoint titration technique (eptt). in the plaque test, monolayers of cells grown in plastic or glass petri dishes are inoculated with dilutions of a viral suspension. after adsorption of infectious virus particles to the host cell, the monolayers are overlaid with an agarosecontaining medium so that the newly formed virus particles are localized by the solid agar over layer. these newly formed infectious particles spread from the initially infected cell to the adjacent cells and develop well-circumscribed foci of cellular degeneration. these areas of dead cells are called "plaques" and are visualized by staining the cell monolayer with a vital dye, such as neutral red. the plaques may also be detected microscopically by determining the multinucleated cells (e.g., measles) or by immunofluorescence. the concentrations of viral suspensions measured by counting the plaques are expressed as plaque-forming units per ml (pfu ml â��1 ). in the endpoint titration technique, the concentration of infectivity is measured by determining the highest dilution of the suspension, which produces cpe in 50% of the cell cultures inoculated. this dilution is called the 50% tissue culture dose endpoint (tcd 50 ). dilutions are therefore made in a maintenance medium and a certain volume of each of them (0.05-0.1 ml) is added to four or more tube cultures. the proportion of positive cultures is registered for each dilution and the precise dilution at which 50% of the inoculated tube cultures are infected is calculated. at this dilution, the inoculum contains, on average, one tcd 50 or one tissue culture (infectious) dose for 50% of the tissue culture tubes. the influence of a plant extract on virus multiplication can be determined as a viricidal or an antiviral activity. the viricidal activity is measured by titration of the residual infectious virus after incubation of the plant extract with a virus suspension of at least 10 6 tcd 50 ml â��1 . on the other hand, the antiviral activity is determined by comparing the virus titers of infected cells, which have been cultured with a maintenance medium containing plant extracts or test substances and a maintenance medium without test material (colegate and molyneux, 1993) . in contrast with antibacterial screening, no solvents, other than physiological buffer solutions, should ideally be used in the in vitro antiviral screening of plant extracts because the samples have to be added to tissue culture cells. it has been observed that many nonpolar plant extracts, prepared and evaporated, are reasonably soluble in dimethyl sulfoxide (dmso), especially if little or no water is present in the sample and the dissolving sample is heated on a water bath. viricidal and antiviral determinations may then be carried out on test solutions containing not more than 10% and 1% dmso, respectively. therefore, dissolved samples of nonpolar plant extracts in dmso are added dropwise to the maintenance medium in a ratio of 1:10 or 1:100 under stirring. as already mentioned, the maintenance medium may contain antibiotics, such as penicillin g (20 î¼g ml â��1 ), neomycin (1 î¼g ml â��1 ), and amphotericin b (1 î¼g ml â��1 ), in order to avoid sterilization of the test solutions. any contamination by bacteria or fungi would indeed ruin the in vitro antiviral bioassay (colegate and molyneux, 1993) . there are various methods for validation of antiviral activity. the major techniques have been highlighted in the preceding sections and in fig. 16.2. most currently used antiseptics and disinfectants kill pathogenic bacteria and fungi at 25â°c within 5 min when present in a concentration of about 0.5% (3-log titer reduction). because it has been noticed that most of these preparations fail to kill all pathogenic viruses under these circumstances, a method has been developed for testing the in vitro viricidal effect of plant extracts, as will be described in the following section. thoroughly mix the preincubated (25â°c) plant extracts, dissolved in a physiological buffer, or their twofold dilutions (e.g., 1/2 to 1/16), with the same volume of a preincubated (25â°c) virus suspension of, for example, 10 6 pfu ml â��1 or tcd 50 ml â��1 in physiological buffer. incubate the mixture at 25â°c for 5 min. stop the incubation by the addition of a 10fold volume of ice-cold maintenance medium and filter the mixture immediately through a 0.22 î¼m filter to eliminate all possible precipitate. then, filter the ice-cold filtrate through a 0.01 î¼m filter to concentrate residual virus on the filter and separate the virus from possibly cytotoxic plant components, which pass the filter. remove the residual virus from the filter with maintenance medium, supplement with 5% serum (1 ml), sonicate in an ice-bath for 30 s, and titrate in 10-fold dilutions at 37â°c by plaque formation or in microtiter plates according to the eptt. carry out a virus control in a physiological buffer containing no plant extract simultaneously. an essential step of this methodology is the separation of all cytotoxic plant components from the residual virus, which has to be measured at 37â°c. cytotoxic substances have a greater influence on the activity of an extracellular virus at 37â°c than at 25â°c. this step, however, can be omitted when the plant extracts to be tested are not toxic to the host cells under the conditions of the evaluation procedure (colegate and molyneux, 1993) . the eptt technique is performed on preemptied confluent monolayers of vero or other cells, grown in the holes of microtiter plates, which are infected with serial 10-fold dilutions of a virus suspension (100 î¼l). starting with monolayers containing 10 4 cells per hole and a virus suspension of, for example, 10 7 tcid 50 ml â��1 or pfu ml â��1 , infect the first monolayers of cells with a multiplicity of infection (moi). the antiviral activity is expressed as the virus titer reduction at the maximal nontoxic dose (mntd) of the test substance, that is, the highest concentration (î¼g ml â��1 ) that does not affect the monolayers under the antiviral test condition. viral titer reduction factors, that is, the ratio of the viral titer reduction in the absence (virus control) and presence of the mntd of the test sample of 1 ã� 10 3 to 1 ã� 10 4 indicate a pronounced antiviral activity and are suitable as selection criteria for further investigation of plant extracts (colegate and molyneux, 1993) . the eptt is more suitable for testing complex samples, such as plant extracts, for many reasons. (i) first, the concentration of many compounds in the extract remains constant, and consequently the proportion of toxic versus active compounds does not change. (ii) second, the exact duration of the antiviral action can be determined by using the eptt, because the action starts from the moment the extract is added to the cells. (iii) third, the eptt using serial diluted extracts deals with a dynamic process, because the cells are subsequently infected with different moi. (iv) this system allows the correlation of all possible moi values in the same microtiter plate with decreasing amounts of plant extracts, so that the noncytotoxic concentration of plant extracts can be determined. at the same time, a correlation between extract toxicity and antiviral activity according to the corresponding moi can be determined in the same microtiter plate. (v) it can be stated as a general rule that the detected antiviral activity should be stable in at least two subsequent dilutions of nontoxic concentration of the extract; otherwise the activity is directly correlated with the toxicity of the extract or is only viricidal. moreover, a true antiviral product has to protect the cells, which have been infected with low virus dilutions (starting from 0.1 pfu per cell onward). (vi) finally, it should be stressed that all possible steps of virus manipulation are to be completed before the plant extracts are added. this means that an antiviral product tcd 50 ml â��1 ), under nontoxic conditions, must act on virus replication steps after uncoating. when the cells are completely protected only in the lower moi (0.1 tcd 50 ml â��1 ), replication processes before uncoating may be involved. an important aspect of the inhibition of viral cytopathic effect (cpe) is the determination of tcid 50 (50% tissue culture infective dose). after harvesting, dilute the virus stock 10-fold. add 0.1 ml of each dilution in 10 wells each of a 96-well microtiter plate. add 0.1 ml of cell suspension of 10,000 cells/well, incubate at 37â°c with 5% co 2 atmosphere, and observe for vial cpe on alternate days. take a final reading on the fifth day and calculate tcid 50 as per the method of reed and muench (1938) , from which tcid 50 can be further calculated from the log value. an antiviral drug will inhibit the cpe of a virus. therefore, for detecting an antiviral agent, the amount of inhibition of cpe of a virus can be observed microscopically (kenny et al., 1985) . for this purpose, trypsinise the monolayer and allow to seed in 96-well microtiter plates. after a 24-h incubation, wash the monolayer in each well and add different test drug dilutions and incubate. after 24 h, wash the cell culture and inoculate with 0.1 ml of 10 tcid 50 , 50 tcid 50 , and 100 tcid 50 of the virus suspensions in different wells. incubate them for 1 h at 37â°c in an incubator for the adsorption of the virus onto the cells. after incubation, remove excess virus suspension by washing with rpmi. add 0.1 ml of selected concentration of the test compound and keep both virus and cell control wells with 0.1 ml of rpmi containing 2% sheep serum. observe the plates under a microscope every 24 h until the virus control shows 100% cpe and tabulate the results (hu and hsiung, 1989) . trypsinize the cell monolayer, allow to seed in a 96-well microtiter plate and incubate for 24 h at 37â°c with 5% co 2 atmosphere. remove the medium, wash the cell monolayer with rpmi without serum, and add 0.1 ml of different virus suspensions in different wells containing the cell layer and incubate for 1 h for virus adsorption; wash off the excess virus suspension after adsorption. to each well, add the selected concentration of the test drug diluted in rpmi containing 2% sheep serum. to the virus control and cell control, rpmi is added (2% serum) and incubated for 24 h. freeze the plates at â��70â°c and thaw at room temperature a couple of times to liberate the associated virus. determine the virus titer by the end point dilution method and express as tcid 50 (cinatl et al., 1997) . trypsinize the monolayer culture and allow to seed in a 96-well microtiter plate. after a 24-h incubation, wash the monolayer in each well and add different test drug dilutions and incubate. after 24 h, wash the cell culture and inoculate with 0.1 ml of 10 tcid 50 , 50 tcid 50 , and 100 tcid 50 of the virus suspensions in different wells. incubate for 1 h at 37â°c in a co 2 incubator for adsorption of the virus onto the cell. after incubation, remove excess virus suspension by washing with rpmi without serum. add 0.1 ml of the selected concentrations of the test compound and keep both the virus and cell control wells with 0.1 ml of rpmi containing 2% sheep serum. incubate the plates at 37â°c for 72 h. after 72 h, discard the old media from the cell cultures and add 50 î¼l of 2 mg/ml of mtt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) to each well and incubate for 3 h. after 3 h of incubation, discard the mtt and add 100 î¼l of isopropyl alcohol to each culture and set aside for 10 min. record the absorbance using an elisa plate reader at 540 nm. in this experiment, the effect of the test drug on mitochondrial synthesis due to viral infection is studied. the "plaque" is a confined region of contaminated cells formed by multiplying virus particles. the plaques are revealed either as regions of dead/decimated cells recognized by cell stains or as zones of polluted cells by immunostaining. the blended cell monolayer is infected with a log10 dilution of viral plaque-forming unit (pfu) in the absence or presence of the test drug and permitted to adsorb (1 h at 37â°c in 5% co 2 ); afterward, the cells should be washed twice with prewarmed tcid cpe at dilution next above cpe at dilution nex 50 50 50 % % % t t above cpe at dilution next below 50 50 % % % ⧠⩠ⷠminimum essential medium (mem). the overlaid drug dilutions are arranged in the overlay medium on the contaminated culture, without the test drug. then, 45 ml of carboxy methyl cellulose is added to 9 ml of the medium; the plates are incubated for 3-5 days, then settled with 10% formalin or 4% formaldehyde for 30 min. the cells are stained with methylene blue (1 ml/well) or 1% gem violet (w/v), washed, and dried to check the plaques (dark areas) by low-power amplification of a binocular microscope. the antiviral impact should be measured as the percentage inhibition of plaque formation: the concentration of the test drug required to exert 50% of virus inhibition (ic 50 or ec 50 ), as compared with the infection control, is evaluated from the graphical plot as dose-response curves by regression analysis . viruses, for example, influenza, can agglutinate rbcs due to surface ha proteins, which can be analyzed visually by blending viral dilutions with rbc. this can be utilized to inspect the inhibitory impact of any medication on ha. the 10-overlay serially diluted (1-1000x) test drug is used alongside the diluted viral stocks (1:4 to 1:128). this dilution (50 ml/well) is added to drug-containing wells. it should be preincubated for 45 min and mixed with rbc (1/20 in pbs) sample solution. here, up to a specific dilution, the viral particles possibly lose their capacity to agglutinate rbcs, which shows a linkage of the drug with the viral ha. known quantities of virus (moi 5-10) are used for infecting both untreated or drug-treated cells and allowed to adsorb for 45-60 min. the unabsorbed virus particles are washed and fresh media is added to incubate for 24-36 h. then, cells are washed with pbs, fixed with paraformaldehyde (3%-4%), and permeabilized with acetone or triton x-100. the cells are again washed and blocked with 1% bovine serum albumin (bsa) in pbs for 30 min. then, the cells are incubated with mouse or rabbit antibody against a specific viral protein for 1-4 h at 37â°c. after that, the cells are subjected to repeated washing and incubated with a fluorescent-tagged secondary antibody for 1 h and washed again. after washing, the cells are visualized under a fluorescent microscope and compared with the fluorescence of untreated and drug-treated cells. on the other hand, for quantitation, the cells are trypsinized after treatment and fixed with 4% paraformaldehyde. the cells are then washed, permeabilized, and labeled with a fluorescent-tagged antibody, followed by propidium iodide (pi: 50 mg/ml in pbs). the cells are then counted in a fluorescent-activated cell counter to quantitate the fluorescence percentage. known quantities of virus (moi 5-10) are used for infecting both untreated and drug-treated cells, adsorbed for 1 h, washed, and incubated (2-4 days) for evaluation of the inhibition of the virus-induced cytopathic effect (cpe). the virus stock is centrifuged after freeze thawing and diluted for elisa. each well of a plate coated with a virus-specific antibody is mixed with 100 ml of controls or test drug and incubated at room temperature (1 h) with horseradish peroxidase conjugate, alkaline phosphatase, or b-d-galactosidase-labeled virus-specific antibody. the wells are washed five times and the substrate (100 ml) is added and incubated in the dark for 10 min. the reaction is stopped by adding 5% h 2 so 4 solution and the absorbance is read at 450 nm. the 96-well plates are seeded with a quadruplicate cell monolayer having a log 10 dilution of the test drug followed by infection with the virus. after 16-20 h of incubation at 37â°c, the monolayers are fixed with 0.05% glutaraldehyde and examined for virus-specific protein(s) on the cell surface. the elisa should be performed with a monoclonal antibody to the specific protein of the corresponding virus and protein and the od (optical density) is measured at 450 nm. the concentration is calculated by 50% reduction in od values (ec 50 ) from extrapolating graphical plots followed by the determination of si (ratio of cc 50 :ec 50 ) in which the results are expressed as a percentage of virusinfected cells (virus control) . the test drug and the virus (10 4 pfu/ml) are mixed to incubate for 1 h at 37â°c. then, immediately dilute the virus-drug mixture to 100-fold (final inoculums 50 pfu/well) with media containing 2% fbs to get a subtherapeutic concentration of mean number of plaques in control mean number of plaques in sample m ean number of plaque in control the test drug. following that, mix the monolayer, with the virus inoculums seeded using a 12-well plate. alternately, add the virus-test drug mix diluted to 100-fold, with no incubation period, with the respective cells for infection. allow to adsorb for 1 h at 37â°c, discard the diluted inoculums, and wash the cells with pbs. pour an overlay medium (with 2% fbs), and incubate at 37â°c for 72 h, followed by plaque reduction assay. count the viral plaque numbers obtained from infections set in the presence of the test drug and compare it with the control. viral attachment to the cell surface is carried out at 4â°c, as it permits binding, but stops viral entry, by elisa. briefly, incubate susceptible cells (2 ã� 10 4 cells/well) in 96-well plates and allow growth overnight. the cell monolayers are cooled at 4â°c. the cells are infected with the virus (moi 5) using heparin in presence of the test drug for 3 h at 4â°c as a control. after washing the wells with ice-cold pbs, fix with prechilled 4% paraformaldehyde in pbs for 1 h on ice, blocked with 5% bsa at 4â°c. the samples are incubated at 37â°c for 1 h with a primary antibody in pbst pbs with 0.05% tween 20 along with 5% bsa. the wells are washed twice with pbst, 5% bsa, and again only with pbst twice, at 5-min intervals on a shaker. this is mixed with secondary antibody in pbst with 5% bsa and incubated at 37â°c for 1 h. the reaction is developed with a 3,3â�²,5,5â�²-tetramethyl-benzidine two component microwell peroxidase substrate for 20 min; the reaction is stopped with 1 m phosphoric acid. the absorbance is measured at 450 nm, and the values are expressed as the fold change of absorbance relative to the mock infection control (lin et al., 2011) . the cell monolayers are cooled and grown in 12-well plates at 4â°c for 1 h. subsequently, infect the prechilled cells with hsv-1 (100 pfu/well) and incubate for 3 h at 4â°c to allow for viral adsorption. incubate the infected cell monolayers in the presence of test drug or heparin (100 mg/ml) for an additional 20 min at 37â°c to facilitate hsv-1 penetration. the extracellular virus is inactivated by citrate buffer (ph 3.0) for 1 min, and the cells are washed with pbs followed by overlay with dmem containing 2% fbs. after 48 h of incubation at 37â°c, the viral plaques are stained and counted (lin et al., 2011) . add the plated cells (0.8 ã� 10 5 cells/well for a 12-well plate) grown overnight at 30% confluence (300 ml) with virus dilution and deae dextran at a final concentration of 20 mg/ml. after adsorption (2 h at 37â°c in co 2 incubator), place the plates in a rocker to prevent the cells from drying and add fresh medium (1-2 ml) containing the test drug to each well and incubate for 40-48 h in 5% co 2 at 37â°c for subconfluent growth. after removing the media, add fixing solution (1-2 ml) to each well and incubate for 5 min at room temperature (î²-galactosidase activity decreases dramatically if the fixing solution is left for >10 min). then, discard the fixing solution, wash the cells twice with pbs, stain, and incubate at 37â°c for 50 min. finally, stain the plates to count the number of blue syncytia and express the titration values as the number of stained cells multiplied by the viral dilution . this assay is applicable for hiv-1, simian immunodeficiency virus (siv), and simian-hiv and is carried out in tzm-bl cells as it reveal the reduction in tat-induced luciferase (luc) reporter gene expression after a single round of virus infection. place the tzm-bl cells (4 ã� 10 4 /well) in a 24-well plate and incubate overnight. in a separate vial, mix the hiv-1nl4.3 (moi 0.05) virion with the test drug or vehicle for 1 h at 37â°c, then add to tzm-bl cells and incubate for 4 h. wash the cells (with cold pbs), and add fresh media with the test drug to culture for 48 h, using untreated hiv-1-infected cells (negative) and azidothymidine (azt)-treated cells (positive) as controls. wash the cells twice with pbs, lyse with 1x lysis buffer, and add the supernatant with the substrate, which should then be analyzed for luciferase activity in an optiplate using a fluorimeter. the results are expressed as percentage inhibition: and the percent inhibition is calculated by subtracting the above value from 100 (wan et al., 2012) . luminescence in the experimental group test drug or azt lu / m minescence of infected cells without the drug u100 (b) cem-green fluorescent protein (gpt) cell-based assay cem-gfp is a stable t-cell line-containing a plasmid encoding gfp and is suitable for hiv-1nl4.3 (moi 0.05) culture. for postinfection, incubate the cells (2.0 ã� 10 5 /well) with the test drug up to 8 days, using azt and solvents (used to prepare the test drug) as control(s). lyse the virus-infected cells with 1x promega cell lysis buffer (150 ml), and transfer to a culture plate to read the absorbance at 485 nm (excitation) and 520 nm (emission) by a fluorimeter. the results can be expressed as percentage inhibition: with the he percent inhibition calculated by subtracting the above value from 100 . place hep ad38 cell suspension (6 ã� 10 5 viable cells/ml of hep ad38 seeding medium) in a 96-well microtiter plate, and incubate at 37â°c for 3 days. discard the medium and wash the cell monolayers with warm (37â°c) dpbs. to the proper wells, add 100 î¼l of hepad38 assay medium that contains either test or control compounds at the desired concentrations. also include wells with hep ad38 assay medium alone as "virus only" controls. incubate at 37â°c for 3 days. on day 3, wash the cells once with warm dpbs and add fresh medium containing the appropriate compound to the wells. after 24 h, transfer the supernatants to v-bottomed 96-well plates and remove cellular debris by centrifugation (15 min, 2500 rpm at 4â°c). transfer 90 î¼l of the clarified supernatants to new v-bottomed plates and store at â��70â°c for quantification of hbv dna. thaw the supernatants that were collected and add 90 î¼l of 2x denaturation solution to each well and mix. incubate at 37â°c for 20 min. cut the nylon membrane to size and prepare it for blotting by wetting it first with distilled water and then 20x hybridization buffer, ssc (saline sodium-citrate). dot-blot the denatured supernatants on to the nylon membrane as directed by the manufacturer. wash the blot with 200 î¼l of neutralization solution followed by 200 î¼l of 20x ssc. remove the blot, rinse it briefly in 2x ssc, and then crosslink the dna to the nylon filter by uv irradiation. prehybridize the blot at 42â°c for 1 h in 20 î¼l of hybridization solution. prepare a 32p-labeled probe by random priming using a portion of the hbv genome as a template. purify the probe through a clontech chroma spin column. denature the probe by boiling for 5 min and add it immediately to the hybridization solution. hybridize the nylon filter overnight at 42â°c. wash the nylon filters twice with 50 ml of 2x ssc, 0.1% sds (sodium dodecyl sulfate) at room temperature for 20 min and twice with 50 ml of 0.2x ssc, 0.1% sds at 65â°c for 20 min. expose the nylon filters to a molecular imager screen for 4 h and scan on a phosphor imager to obtain the data. to determine the percent inhibition of hbv replication, subtract the background value (counts of radiation detected from the nylon filter itself) from all control and experimental values. divide the average values of the experimental wells (cells treated with test compounds) by the average value for the "virus only" control (cells not treated with compound or tetracycline during the experiment) and multiply this number by 100 (king and ladner, 2000) . the above mentioned in vitro studies are listed in table 16 .2. drug development programs include preclinical screening of immense quantities of chemicals for specific and nonspecific cytotoxicity against numerous sorts of cells, which is imperative to show the potential therapeutic target and safety evaluation. the screening of plant extracts or pure compounds for investigating their antiviral properties can be more significant with cytotoxicity measures (meyer et al., 1982) . it is essential for an investigational item to establish the antiviral activity at concentrations that can be accomplished in vivo without inducing toxicity to cells. moreover, in a cell culture display, antiviral activity of an investigational item can be the aftereffect of host cell death after exposure to the item. cytotoxicity tests utilize a series of increasing concentrations of the antiviral product to determine what concentration results in the death of 50% of the host cells. this value is referred to as the median cellular cytotoxicity concentration (cc50 or ctc50 or ccic50). the relative effectiveness of the investigational product in inhibiting viral replication compared with inducing cell death is defined as the therapeutic or selectivity index (cc50 value/ec 50 value). it is desirable to have a high therapeutic index giving maximum antiviral activity with minimal cell toxicity. according to us fda guidelines, it is recommended to determine cc50 values in both stationary and dividing cells from multiple relevant human cell types and tissues to establish the potential for cell cycle, species, or tissue-specific toxicities. studies determining cytotoxicity and therapeutic indexes should be conducted before the initiation of phase 1 clinical studies. there are a number of advantages for in vitro testing using cell cultures, which include gfp fluorescence in the experimental group fluorescence in / i infected cells without the test drug ã�100 analysis of species specificity, feasibility of using only small amounts of test substances, and facility to do mechanistic studies (guidance for industry, 2006). after confirming the cytotoxic concentration, the drug concentrations are selected for antiviral studies based on the percentage viability of cells and are used to study the antiviral activity by cpe inhibition assay, virus yield assay, followed by mtt assay. any compound that is cytotoxic to cells inhibits the cell proliferation and kills the cells. trypan blue is a dye that is capable of penetrating dead cells; therefore, the dead cells take up the blue stain whereas the viable cells do not. this method gives an exact number of dead and viable cells (strober, 2001) . protein content is widely used for estimating total cellular material and can be used in growth experiments. the colorimetric method of estimating protein is more sensitive. the cell pellets are treated with 11% cold trichloroacetic acid to remove amino acid pools and dissolved in alkaline cupric sulfate and folin ciocalteau phenolic reagent. folin's reagent and cupric sulfate together react with amino acid to give a blue color and this color intensity is proportional to the protein concentration, which can be measured colorimetrically (maya et al., 1995) . to proceed with the same technique, the cells from the wells were trypsinized using 100 î¼l trypsin and transferred into eppendorf tubes and centrifuged at 5000 rpm for 10 min to obtain pellets. the cell pellets are dissolved in naoh and diluted , tzm-bl cell-based assay (hiv), cem-green fluorescent protein cell-based assay (hiv), hep ad38 assay (hbv), immunofluorescence assay, enzyme-linked immunosorbent assay (elisa) â�¢ reduction or inhibition of virus-specific polypeptides synthesis in infected cell cultures, e.g., viral nucleic acids, determination of the uptake of radioactive isotope labeled precursors or viral genome copy numbers other assays for validation of antiviral activity â�¢ virus inactivation assay, virus adsorption assay, virus attachment, and penetration assay to 0.1 n. the test drug is to be added to 200 î¼l of protein sample, mixed, and left for 10 min. to this, 100 î¼l of test reagent is added with constant mixing and left for 40 min in incubator. the absorbance was read at 655 nm using an elisa reader (bio-rad). the color development was correlated with the cell number as follows: the cytotoxic concentration found by dye exclusion techniques gives superficial data. the selected concentrations from a trypan blue dye exclusion study are used further for estimating proteins. mtt (3-(4,5-dimethylthiazol-2yl)-2,5 diphenyl tetrazolium bromide) in live cells enters the cells and enzyme succinate dehydrogenase present in mitochondria reduces it to formazan blue product. the color intensity is directly proportional to the number of live cells. to perform this process, the plates were seeded with hep-2 cells at 10,000 cells/well. they are incubated for 24 h. after 24 h, the medium is discarded and drug concentrations were added and incubated for 72 h. then, 50 î¼l of 2 mg/ml of mtt is to be added and incubated for 3 h and then 100 î¼l of isopropyl alcohol is added and absorbance is read at 540 nm in an elisa plate reader (bio-rad). the results are tabulated and percentage growth inhibition is calculated using the following formula: the concentrations of the test drug used in the previous experiments can be further confirmed by studying the mitochondrial synthesis by mtt assay. the formazan blue color formation is directly proportional to the number of viable cells and therefore the absorbance is to be read at 540 nm. in this test, brine shrimp (artemia salina) eggs are hatched in artificial sea water (38 g/l of sea salt). the brine shrimp test (bst) bioassay experiment is performed according to the procedure described by meyer et al. (1982) . generally, samples of the test drugs for the experiment are prepared in methanol solution, which acts as control vehicle. after 48 h of incubation, 10 brine shrimps are transferred to each sample vial using a pasteur pipette and artificial sea water is added to make 5 ml. sample vials are previously prepared by dissolving specific concentrations of test drugs with different dilutions. the solvent is then evaporated overnight. survivors are counted after 24 h and the lc 50 values, with 95% confidence intervals are determined using probit analysis, as described by finney (1971) . control vials are prepared using methanol only. three replicates are prepared for each concentration of the test drugs. control disks are prepared using only methanol. replicates are prepared for each dose level. to begin the bioassay, brine shrimp eggs are hatched in a shallow rectangular dish (22 ã� 32 cm 2 ) under the same conditions described in the literature except that natural instead of artificial seawater is used. ten shrimps are selected and transferred into each sample vial by means of a 23-cm disposable pasteur pipette and the final volume in each vial is adjusted to 5 ml using natural seawater. a drop of dry yeast suspension (3 mg in 5 ml seawater) is added as food to each vial. the vials are maintained under illumination. survivors are counted with the aid of a stereomicroscope, after 6, 24, and 48 h, and the deaths at each dose level and control are determined. no deaths are usually observed to occur in the control after 48 h. the brine shrimp test (bst) represents a rapid, inexpensive, and simple bioassay for testing plant extract lethality, which, in most cases, correlates reasonably well with cytotoxic properties (mclaughlin, 1991) . following the procedure of meyer et al. (1982) , the lethality of the test drugs/plant extracts to brine shrimp is determined. the lethal concentrations of test drugs/plant extract resulting in 50% mortality of the brine shrimp (lc 50 ) and 95% confidence intervals are determined from the 24 and 48-h counts and the dose-response data are transformed into a straight line by means of a trend line fit linear regression analysis; the lc 50 is derived from the best-fit line obtained. caffeine (lc 50 = 306 î¼g/ml) (meyer et al., 1982) is used as a positive control and methanol (500 î¼l) as a solvent and a negative control in the bioassay experiments. the current scenario of viral diseases is lethal and there is an upsurge in new viral diseases and resistance to existing viral infections worldwide. the currently accessible antivirals, however effective, are exorbitant and past the reach of a majority of individuals. along these lines, the advancement of safe, effective, and low-cost antiviral medications, for example, rt inhibitors, is among the top priorities, as many viral infections are not yet treatable and have high death rates. for the past few years, substantial work has been carried out regarding the effectiveness of medicinal plants on hiv infection (premanathan et al., 1999; calabrese et al., 2000; asres et al., 2001) and an increasing popularity of over-the-counter plant products containing orthodox drugs has been observed. the main focus is to lower the adverse effects associated with viral infections and an inclination toward synergistic interactions of multiple molecules present in plant extracts. be that as it may, because mostly pharmacological mechanisms of the combinations are not studied, antagonistic impacts or remedial disappointments have been seen (chan et al., 2000) . a prerequisite that should be considered significant for medicinal plants is to identify and standardize the method of extract preparation, the suitable season for collecting plant material, and the details of its administration (chattopadhyay et al., 2006) . as a lot of plant extracts and subsequent formulations have shown significant outcomes, it seems to be rational to endorse the idea of the study of medicinal plants as a quest to find potential antivirals. antiviral investigation on the flavonoids of chamaesyce thymifolia investigation of medicinal plants of togo for antiviral and antimicrobial activities in vitro virucidal activity of selected anthraquinones and anthraquinone derivatives antiviral evaluation of plants from brazilian atlantic tropical forest antiviral activity against human immunodeficiency virus type 1 (hiv-1) and type 2 (hiv-2) of ethnobotanically selected ethiopian medicinal plants suppression of hepatitis c virus by the flavonoid quercetin is mediated by inhibition of ns3 protease activity anti-herpes virus activities of bioactive fraction and isolated pure constituent of mallotus peltatus: an ethnomedicine from andaman islands the mannose-specific plant lectins from cymbidium hybrid and epipactis helleborine and the (n-acetylglucosamine) n -specific plant lactin from urtica dioica are potent and selective inhibitors of human immunodeficiency virus and cytomegalovirus replication in vitro 1-cinnamoyl-3,11-dihydroxymeliacarpin is a natural bioactive compound with antiviral and nuclear factor-kappa b modulating properties a high throughput colorimetric cell proliferation assay for the identification of human cytomegalovirus inhibitors an investigation of the antiviral activity of podophyllum peltatum in vitro anti-hiv-1 activities of kaempferol and kaempferol-7-o-glucoside isolated from securigera securidaca further screening of venda medicinal plants for activity against hiv type 1 reverse transcriptase and integrase the natural compound silvestrolis a potent inhibitor of ebola virus replication plant products as topical microbicide candidates: assessment of in vitro and in vivo activity against herpes simplex virus type 2 a phase i trial of andrographolide in hiv positive patients and normal volunteers comparative study of propofol versus midazolam in the sedation of critically ill patients: results of a prospective, randomized, multicenter trial survey for the presence and distribution of human herpesvirus 8 in healthy brain ethnomedicines and ethnomedicinal phytophores against herpes viruses antivirals of ethnomedicinal origin: structure-activity relationship and scope dose dependent therapeutic antiinfectives from ethnomedicines of bay islands recent advancements for the evaluation of anti-viral activities of natural products validation of antiviral potential of herbal ethnomedicine inhibitory effects of quercetin 3-rhamnoside on influenza a virus replication anti-herpes simplex virus (hsv-1) activity of oxyresveratrol derived from thai medicinal plant: mechanism of action and therapeutic efficacy on cutaneous hsv-1 infection in mice chemistry, biological activity, and chemotherapeutic potential of betulinic acid for the prevention and treatment of cancer and hiv infection antiviral effects of 6-diazo-5-oxo-1-nor-leucine on replication of herpes simplex type-1 novel compounds in preclinical/early clinical development for the treatment of hiv infections molyneux bioactive natural products plant substances as antiviral agents: an update potential antiviral lignans from the roots of saururus chinensis with activity against epstein-barr virus lytic replication drug screening for autophagy inhibitors based on the dissociation of beclin1-bcl2 complex using bifc technique and mechanism of eugenol on anti-influenza a virus activity structure and in vitro antiviral activity of triterpenoid saponins from calendula arvensis antiviral activity of chlorogenic acid against influenza a (h1n1/h3n2) virus and its inhibition of neuraminidase resveratrol inhibition of herpes simplex virus replication antiviral activities of various water and methanol soluble substances isolated from ganoderma lucidum sennoside a, derived from the traditional chinese medicine plant rheum l., is a new dual hiv-1 inhibitor effective on hiv-1 replication anti-enterovirus and immunostimulating activity of the polyphenol complex extracted from pethaphylloides fruticosa (l.) o. schwarz honokiol, a lignanbiphenol derived from the magnolia tree, inhibits dengue virus type 2 infection screening of brazilian plants for antiviral activity against animal herpes viruses probit analysis antiviral effects of glycyrrhiza species biotransformation of ursolic acid by syncephalastrum racemosum cgmcc 3.2500 and anti-hcv activity anti-aids agents 11. betulinic acid and platanic acid as anti-hiv principles from syzygium claviflorum, and the anti-hiv activity of structurally related triterpenoids antiviral activity of dammarane saponins against herpes simplex virus type 1 activity of melaleuca alternifolia (tea tree) oil on influenza virus a/pr8: study on the mechanism of action antiviral activity of an extract derived from roots of eleutherococcus senticosus search for antiviral agents antiviral product development-conducting and submitting virology studies to the agency. u.s. department of health and human services, food and drug administration michellamines d-f, new hiv-inhibitory dimeric naphthylisoquinoline alkaloids, and korupensamine e, a new antimalarial monomer, from ancistrocladus korupensis virucidal effects of the steam distillate from houttuynia cordata and its components on hsv-1, influenza virus, and hiv inhibitory effect of ferulic acid and isoferalic acid on murine interleukin-8 production in response to influenza virus infections in vitro and in vivo a modified plaque method for arboviruses on plastic panels evaluation of new antiviral agents: i, in vitro perspectives anti-viral effect of a compound isolated from liriope platyphylla against hepatitis b virus in vitro isolation of the anthropogenic compound fluoranthene in a screening of chinese medicinal plants for antiviral compounds further investigations on the antiviral activities of medicinal plants of togo antiviral activities in plants endemic to madagascar inhibitory effects of sudanese medicinal plant extracts on hepatitis c virus (hcv) protease study of antiviral action of total alkaloids from haemanthus albiflos inhibitory effect of glycyrrhizin on the in vitro infectivity and cytopathic activity of the human immunodeficiency virus antiviral potential of selected indian medicinal (ayurvedic) plants against herpes simplex virus 1 and 2. n anti-hbv active constituents from piper longum the flavonoid ellagic acid from a medicinal herb inhibits host immune tolerance induced by the hepatitis b virus-e antigen comparison of specific antiviral agents in herpes simplex keratitis in vitro and in vivo anti picorna virus activity of some phenoxypyridine carbonitriles extracts and molecules from medicinal plants against herpes simplex viruses hep ad38 assay a high-throughput, cell-based screen for the evaluation of compounds against hepatitis b virus samarangenin b from limonium sinense suppress herpes simplex virus type 1 replication in vero cells by regulation of viral macromolecular synthesis antiviral activities against hsv-1, hcmv, and hiv-1 of rhamnan sulfate from monostroma latissimum antiviral effects of black raspberry (rubus coreanus) seed and its gallic acid against influenza virus infection in vitro antiviral activities of chinese medicinal herbs against duck hepatitis b virus plant antiviral agents iii. isolation of alkaloids from clivia miniata regel (amaryllidaceae) isolation and purification of baicalein, wogonin and oroxylin a from the medicinal plant scutellaria baicalensis by high-speed counter-current chromatography antiviral activity and mode of action of caffeoylquinic acids from schefflera heptaphylla (l) identification of natural compounds with antiviral activities against sarsassociated coronavirus mechanism of action of glycyrrhizic acid in inhibition of epstein-barr virus replication in vitro hydrolyzable tannins (chebulagic acid and punicalagin) target viral glycoproteine glycosaminoglycan interactions to inhibit herpes simplex virus 1 entry and cell-to-cell spread saikosaponin b2 is a naturally occurring terpenoid that efficiently inhibits hepatitis c virus entry ethnopharmacology in overdrive: the remarkable anti-hiv activity of artemisia annua the alkaloids. vol antiviral potential of curcumin a search for anti-viral properties in panamian medicinal plants, the effects on hiv and its essential enzymes interaction of filacial proteins on growth regulation of normal lung epithelial cells in vitro antiviral screening of british columbian medicinal plants crown-gall tumors in potato discs and brine shrimp lethality: two simple bioassays for higher plant screening and fractionation the in vitro antivirial activity of an aliphatic nitro compound from heteropteris aphrodisiaca brine shrimp: a convenient general bioassay for active plant constituents natural products and drug development. munksgaard anti-herpes virus activity of apporphine alkaloids anti-herpes virus activities of achyranthes aspera: an indian ethnomedicine, and its triterpene acid bio organic marine chemistry pedilanthus tithymaloides inhibits hsv infection by modulating nf-îºb signalling screening extracts of zanthoxylum chalybeum and warburgia ugandensis for activity against measles virus (swartz and edmonston strains) in vitro biological activity of guatteria cardoniana fractions comparison of two colorimetric assays to determine viral infectivity in microculture virus titration characteristic of alkylated chalcones from angelica keiskei on influenza virus neuraminidase inhibition glycyrrhizic acid inhibits virus growth and inactivates virus particles in vitro anti-human immunodeficiency virus activity of polysaccharide from rhizophora mucronata poir maslinic acid, a natural triterpenoid compound from olea europaea, protects cortical neurons against oxygen-glucose deprivation induced injury in vitro study of the antiviral activity of some b-carboline alkaloids a simple method of estimating fifty percent endpoints anti-hiv activity of extracts and compounds from algae and cyanobacteria antiviral flavonoid from pterocaulon sphacelatum, an australian aboriginal medicine in vitro antiviral activity of the anthraquinone chrysophanic acid against poliovirus antiherpes virus activity of extracts from the medicinal plant geranium sanguineum l antiviral agents as adjuncts in cancer chemotherapy effects of phyllanthus plant extracts on duck hepatitis b virus in vitro and in vivo antiviral activity of carnosic acid against respiratory syncytial virus in vitro antioxidant activity of polyphenol extracts with antiviral properties from geranium sanguineum l a new antiviral and antimicrobial sesquiterpene from glyptopetalum sclerocarpum trypan blue exclusion test of cell viability antiviral activity and constituent of ardisia chinensis benth against coxsackie b3 virus analysis of anti-rotavirus activity of extract from stevia rebaudiana proanthocyanidin from blueberry leaves suppresses expression of subgenomic hepatitis c virus rna anti-viral activity of the extracts of a kenyan medicinal plant carissa edulis against herpes simplex virus screening of higher plants for biological activities. ii. antiviral activity plant products as potential antiviral agents plant antiviral agents: v. 3-methoxyflavones as potent inhibitors of viral-induced block of cell synthesis in vitro antiviral activity of plant extracts from asteraceae medicinal plants current organic chemistry, natural product chemistry issue plant flavonoids in biology and medicine ii: biochemical, cellular and medicinal properties inhibition of hepatitis c virus replication by chalepin and pseudane ix isolated from ruta angustifolia leaves fangchinoline inhibits human immunodeficiency virus type 1 replication by interfering with gp160 proteolytic processing herbs of the genus phyllanthus in the treatment of chronic hepatitis b: observations with three preparations from different geographic sites effect of oenanthe javanica flavone on human and duck hepatitis b virus infection antiviral effect of cimicifugin from cimicifuga foetida against human respiratory syncytial virus three new secoiridoids, swermacrolactones a-c and anti-hepatitis b virus activity from swertia macrosperma lignans with antihepatitis b virus activities from phyllanthus niruri l antiviral activity of polymethoxylated flavones from guangchenpi, the edible and medicinal pericarps of citrus reticulata 'chachi the in vitro activity of geraniin and 1,3,4,6-tetra-o-galloyl-beta-d-glucose isolated from phyllanthus urinaria against herpes simplex virus type 1 and type 2 infection the protective effect of 3-deoxysappanchalcone on in vitro influenza virusinduced apoptosis and inflammation mechanism of inhibition of hiv-1 infection in vitro by purified extracts of prunella vulgaris evaluation of anti-hsv-2 activities of barleria lupulina and clinacanthus nutans novel antiviral activity of baicalein against dengue virus a dihydro-pyrido-indole potently inhibits hsv-1 infection by interfering the viral immediate early transcriptional events comparative inhibitory effects of suramin and other selected compounds on the infectivity and replication of human t-cell lymphotropic virus (htlv-iii)/lymphadenopathy-associated virus (lav) discovery of cyanovirin-n, a novel human immunodeficiency virus-inactivating protein that binds viral surface envelope glycoprotein gp120: potential applications to microbicide development emerging anti-hiv drugs agar diffusion method for detection and bioassay of antiviral antibiotics anti-herpes virus activity of aporphine alkaloids antiviral potentials of medicinal plants evaluation of anti-infective potential of a tribal folklore odina wodier roxb against some selected microbes and herpes simplex virus associated with skin infection sensitive and rapid assay on mt-4 cells for the detection of antiviral compounds against the aids virus a rapid and simple colorimetric test for the study of anti-hiv agents plant-derived leading compounds for chemotherapy of human immunodeficiency virus (hiv) infection resistance of human immunodeficiency virus type 1 to the high-mannose binding agents cyanovirin n and concanavalin a key: cord-024652-4i6kktl0 authors: santra, hiran kanti; banerjee, debdulal title: natural products as fungicide and their role in crop protection date: 2020-05-12 journal: natural bioactive products in sustainable agriculture doi: 10.1007/978-981-15-3024-1_9 sha: doc_id: 24652 cord_uid: 4i6kktl0 seeking solutions from nature for solving one and all problems is the age-old practice for mankind, and natural products are proved to be the most effective one for keeping up the balance of development as well as the “healthy, wealthy, and well” condition of mother nature. fungal pathogens are proved to be a common and popular contaminant of agroecosystem that approximately causes 70–80% of total microbial crop loss. to meet the proper global increasing need of food products as a result of population explosion, managing agricultural system in an eco-friendly and profitable manner is the prime target; thus the word “sustainable agriculture” plays it part, and this package is highly effective when coupled with nature-derived fungicidal products that can minimize the event of fungal infections in agrarian ecosystem. present study enlists the most common and effective natural products that might be of plant or microbial origin, their mode of action, day-by-day development of phytopathogenic resistance against the prevailing fungicides, and also their role in maintenance of sustainability of agricultural practices with special emphasis on their acceptance over the synthetic or chemical one. a large number of bioactive compounds ranging from direct plant (both cryptogams algae and moss and phanerogams)-derived natural extracts, essential oil of aromatic plants, and low-molecular-weight antimicrobial compounds known as phytoalexins to secondary metabolites that are both volatile and nonvolatile organic compounds of microbes (fungal and actinobacterial members) residing inside the host tissue, called endophyte, are widely used as agricultural bioweapons. the rhizospheric partners of plant, mycorrhizae, are also a prime agent of this chemical warfare and protect their green partners from fungal invaders and emphasize the concept of “sustainable agriculture.” natural products are the best weapon for the survival of any type of problems regarding infection, pathogenesis, or protection from diseases. due to their degradability in nature, they are the first options to be used by agriculturalists and plant biologist for combating fungal pathogenesis. the eukaryotic organism fungi have a separate kingdom in whittaker's five kingdom classification and are prime member of this ecosystem as a potent decomposer. in spite of their heavy and multidimensional applications in agricultural, medicinal, and industrial field ranging from the production of life-saving medicines to food supplements, they are the cause of huge global crop loss each year and lead to economic exhaustion. macro-and microscopic fungi-producing fruit bodies on different portions of a plant body (stem, leaf, fruit, root) lead to the death and decline of the crop species. several methods have already been tried since the start of civilization for crop protection but because of plant and fungal coevolution, fungi have dominated on the green eukaryotes and caused significant reduction in the crop yield. particularly in a country like india where the central gdp largely depends on agricultural output, the fungal pathogenesis has been a matter of grave concern for the agriculture department and policy makers. huge amount of money and manpower is invested to fight against the fungal diseases for ensuring higher and qualitative yield, but still it has been a burning problem of today's conditions. the problem with chemical and synthetic tools for combating the parasitic infections includes their toxicity leading to quality deterioration and environmental pollution accompanied with side effects on human health. in a case study, it has been reported that the extreme use of antibiotics in agricultural field and their direct consumption by humans through their daily meal have led to resistance of those antibiotics in human fungal pathogens. so we are in search of bioactive agents that will be of biological origin, selective to their host, and produce no secondary symptoms with least negative impact. the problem with fungi is their secretion of various types of mycotoxins (aflatoxins, ochratoxins, patulin, fumonisin, zearalenone, deoxynivalenol, etc.) in the stored food products, causing postharvest loss of cereals, pulses, dry fruits, and spices. mycotoxins are not only food spoilers but also potent disease-causing agents in humans leading to cancer, liver damage, kidney failure, and paralysis (miller 1995) . the severe effects of fungal crop loss are visible largely in tropical or subtropical regions where the temperature is moderately higher than the other parts of the world. fungal devastation occurs in two phases: firstly, when the crops are growing on the field and, secondly, when they are stored for further transportation, postharvest loss. the third type of contamination occurs when the microscopic airborne pathogens like molds grow on cooked foods and lead to food spoilage. at each and every level, scientists have developed techniques to minimize fungal food loss. on a gross annual estimate, almost 25% of agricultural food items are of no use due to fungal contamination (pittet 1998) . the major issues with fungi-related crop loss are deterioration as a result of increase of fatty acid conditions, change of color and texture of food items, poor nutritional conditions, and poor germinability of stored seeds (dhingra et al. 2001) . reports from asia and africa include death of humans and animals due to consumption of mycotoxin-contaminated foods (reddy and raghavender 2007) . fungal pathogens are sometimes dependent on more than one host for their successful completion of life cycle and disease development (puccinia graminis var. tritici, causal agent of black stem rust of wheat that requires berberis aristata for successful infection other than there main target wheat plant). so physical controls like eradication of secondary or collateral host and burning of the old livestocks and remnants of the field are the primary measures adopted by the farmers for disease-free crop production. so maintaining the sustainability along with less pathogenic infection is the deep ecological movement for crop maintenance. there are reports of resistance developed against the common and widely used antibiotics of agricultural importance. blasticidin s, an antibiotic obtained from streptomyces sp. (a type of actinobacteria predominantly present in soil samples), interacts with the protein synthesis and causes the death of the rice blast pathogens. development of resistance of this antibiotic is reported to be present in some fungal pathogens that detoxify it by deamination (dayan et al. 2009 ). compounds of bacterial and fungal origin from both soil and endophytic sources are used as an alternative source over the chemical ones. plant extracts especially essential oils from plant taxa of lamiaceae family are of immense importance and are used as fungicidal or fungistatic. most of the active ingredients act upon the fungal cell wall by either blocking the cellular processes like respiration, cell wall and cell membrane synthesis, ergosterol biosynthesis, protein synthesis, or dna replication. not only the secondary metabolites of plant and microbial origin but also the direct application of microorganisms in terms of biocontrol agent could be used as potent antifungals. other than these, plants' own defense molecules, known as the phytoalexins, could provide a strong line of defense against mycorrhizae; the root symbionts of higher plants can physically, biologically, and biochemically protect the plant root from pathogenic invasion and provide an enhanced resistance conditions to their hosts. this study includes the role of these compounds as natural agents of antifungal property and their role in disease prevention. mycorrhizae as a biocontrol agent mycorrhiza being the perfect example of symbiosis is known to be the oldest association between higher plant (both angiosperm and gymnosperm, monocot and dicot plants) and fungi and is an astonishing phenomenon of nature. the mycorrhizal association is one of nature's privileges for maintaining the sustainability of agriculture. in present day's changing environment, haphazard use of pesticides (fungicides) and chemicals poses a great risk to the existence and survival of mycorrhizal species in its complete biologically active form. there is a need to increase awareness in order to save mycorrhizal fungi from extinction. plants form beneficial association with other variants of life forms (animals, bacteria, or fungi) to complete their life processes, to fight against pathogenic microorganisms, and most importantly to thrive in adverse environmental situations. the plant root and its associated living microbial flora are together called "rhizosphere," particularly the area of mycorrhizal occurrence. the term mycorrhiza is derived from two greek words: mycos which means fungus and rhiza which means roots. in nature, more than 80% of angiosperms and almost all of gymnosperms are known to have mycorrhizal associations. the common two types of mycorrhizal associations that exist in nature are endomycorrhizae, also called arbuscular mycorrhizae (am), for example, endogone sp. and rhizophagus sp., and ectomycorrhizae (em), for instance amanita muscaria and laccaria bicolor. mycorrhizal associations support its host plants to survive in untimely soil conditions and drought situations by increasing the surface area of root and efficiency of mineral uptake. environmental threats including problems of temperature increase, climate changing, drought, and infertility of soil are some of the major challenges in agriculture and have to be mitigated to ensure global food security. in this context, mycorrhiza-based crop production is one of the key components of sustainable agriculture practices. in most of the cases, am fungi-mediated suppression of root pathogenic fungi is achieved by either morphological, physiological, or biochemical alterations of the host. several experiments on fungistatic activity of the mycorrhizal species have been done, and fruitful results are found against pathogenic fungi such as aphanomyces spp., botrytis fabae, chalara (thielaviopsis) basicola, dothiorella gregaria, fusarium oxysporum, gaeumannomyces graminis var. tritici, ganoderma pseudoferreum, pythium ultimum, p. splendens, phytophthora parasitica, p. cactorum, p. vignae, rhizoctonia solani, r. bataticola, and sclerotium rolfsii (lioussanne et al. 2009; bagyaraj 2006; bagyaraj and chawla 2012) . the most common outcome of am fungal colonization is seen as an increase in number of branches, resulting in a relatively larger proportion of higher-order roots in the root system. thickening of the cell walls due to lignification and production of polysaccharides in mycorrhizal plants are the common mode of prevention of penetration and growth of pathogens like fusarium oxysporum and phoma terrestris. a huge percentage of am-root pathogen interaction studies have been conducted in crop plants of agricultural and horticultural importance. but the information available on forest tree species is scanty. mycorrhizal technology can thus play an important role in production of low-cost quality seedlings and provide plant protection. like other methods of biological control, am fungi are not able to offer complete immunity against the infection caused by plant pathogens. they could only impart a degree of resistance against soilborne plant pathogens. however, the possibility of biologically controlling soilborne plant pathogens looks promising. am fungi play a protective role for plants by activating the defense mechanisms for the better resistance of crop plants and thus may protect the host plant from further fungal pathogenic attack, thus working as a potent biocontrol agent. researchers have proved that am symbiosis triggers the activation of several defense-related genes and also expression of pathogenesis-related proteins. evidences are drawn from modern techniques like molecular biology methods and immunological and histochemical analysis that strongly supports this concept. am fungi first act as a biotrophic agent, and before entering the host plant's root cell, they cause a sharp change in endogenous salicylic acid that is reflected in quick accumulation of reactive oxygen species (ros), a wide range of hydrolytic enzymes, and also the activation of phenylpropanoid biosynthetic pathway (güimil et al. 2005 , paszkowski 2006 , roman et al. 2011 . research findings have proved that the amount of defense-related compounds (essential enzymes like pal, phenylalanine ammonialyase, a product of phenylpropanoid pathway, enzymes needed for flavonoid or isoflavonoid biosynthesis like chalcone isomerase) that act for the protection of plant from fungal and bacterial pathogen is higher in the case of mycorrhiza-inoculated plant than in the uninoculated ones (volpin et al. 1994 (volpin et al. , 1995 . host's physiological and biochemical processes are greatly influenced by the mycorrhizal association in terms of decreased root exudation, higher concentration of phenylalanine and serine contents, ortho-dihydroxy phenols, increased membrane phospholipid content, etc. (smith et al. 1994) . when the phospholipid contents are high, it reduces the chances of root pathogenic attack, and higher concentrations of ortho-dihydroxy phenols show inhibitory activity against root rot pathogen sclerotium rolfsii (causal agent of southern blight), whereas the non-mycorrhizal plants are affected by the southern blight disease. tomato plants when inoculated with g. fasciculatum show inhibitory activity against root knot nematodes. host-am association leads to the formation of defense-related compounds like phytoalexins, chitinases (chi), β-1,3-glucanase (glu) (enzyme related to hydrolysis of fungal cell wall), peroxidases (pox), hydroxyproline-rich glycoproteins, and phenolics (st arnaud and vujanovic 2007) . synergistic effect of pgprs along with am fungi is proved to be a system of better protection than the use of am fungi alone (linderman 1994; bagyaraj and chawla 2012) . fungal wilt of common medicinal plant indian coleus (coleus forskohlii) caused by fusarium chlamydosporium could be minimized by the joint action of am fungus and trichoderma viride and cause a sharp increase in root yield and root forskolin concentration and may also reduce the severe disease conditions (singh et al. 2012 ). am causes a drastic change in the rhizospheric microbiota and intentionally either removes directly the pathogenic microorganisms or stimulates the accumulation of potent microbial partners especially fungus that are heavily antagonistic to the plant pathogenic ones. plants with mycorrhizal association harbor higher population of rhizospheric microorganisms, thus making it impossible for the pathogen to compete and invade the root. in the case of phytophthora cinnamomi, the numbers of sporangia and zoospores are found to be reduced when rhizospheric soil extracts of am plants are applied; it means the am fungi are able to alter the microbial population and particular functional groups of rhizospheric microorganisms (meyer and linderman 1986; larsen and bodker 2003) . they cause qualitative and quantitative changes in the fungal community by several factors like changed exudation patterns; altered root size and architecture; different physiological and biochemical parameters like sugar, organic acids, and amino acids; and also putative direct am fungal effects (toljander et al. 2007; ahmed et al. 2013; vigo et al. 2000) . fungistatic siderophore (low-molecular-weight chelating agents having higher affinity for ferric ion)-producing microorganisms are found to be crowded in mycorrhiza-infected roots and rhizospheric regions. mycorrhizal plants are to be reported with more actinomycetes and bacterial (gram-positive paenibacillus sp. against phytophthora parasitica) flora antagonistic to soilborne root pathogens (azcon-aguilar and barea 1996; budi et al. 1999 ). apart from providing biochemical and physiological defense strategies, arbuscular mycorrhizal species also exhibit physical barrier of defense by changing the root anatomy, morphology, and even architecture in terms of increased nutrient uptake, meristematic and nuclear activities of root cell, higher rate of growths, and branching patterns (atkinson et al. 1994; gamalero et al. 2010; gutjahr and paszkowski 2013) . thus responses of root morphology as a result from afm colonization seem to depend on plant characters, tap root system, etc. more benefits are seen in tap root system than fibrous root system in terms of gained biomass and nutrient acquisition. though there is a gap of knowledge in how increased root branching caused by mycorrhizal infection help the plant to defend fungal pathogenesis, synergism is seen as something that can balance the suppressed root growth caused by several root pathogens and restore the root health. mycorrhiza-mediated strengthening of the vascular system allows the higher rate of flow of nutrients, increased mechanical strength, and also inactivation of vascular pathogens. in conditions of limited resource such as carbon requirement and space for inoculation, a competition between the symbiotic partner (mycorrhizae) and pathogenic fungi is very common and expected (vos et al. 2014 ). in the direct warfare, mycorrhizae win over the pathogenic one and thus obtain higher amount of nutrients (almost 4-20% of total assimilated carbon by host plant) and occupy large areas of available root cortical cells (jung et al. 2012; vierheilig et al. 2008) . defeating the pathogenic fungi in terms of nutrient uptake and providing a little or no room for infection are probably the mightiest cause of biocontrol ability of am fungus (hammer et al. 2011) . output of am and phytophthora interaction indicates that the pathogen does not penetrate cortical arbuscular cells, suggesting that localized competition for infection site does occur between the pathogenic fungi and the am fungus. not only fungi but also plant-invading nematodes are in the queue for colonization and nutrient uptake (smith 1988) . the infection of southern root-knot nematode (meloidogyne incognita, m. exigua) is reduced when the roots are priorly inoculated with symbiotic partners like in the case of coffee plants also (alban et al. 2013; dos et al. 2010) . reports have suggested that the number of infected sites is reduced within mycorrhizal root system than in the uninoculated one and thus strongly supports the mycorrhizal role as a biofungicide (vigo et al. 2000) . am fungi can help the plant uptake of nutrients like phosphate, nitrogen, minerals, microelements (zinc), and water at a higher rate than the uninfected one (baum et al. 2015; parniske 2008) , and as a result, they are provided with photosynthetic carbon (smith and smith 2011) . the plants capable of absorbing higher amount of nutrients in terms of am fungal association have the potential to tolerate pathogenic infections (karagiannidis et al. 2002) . though the improved nutrition and increased tolerance are not involved in a cause-effect relationship, proofs are there that higher uptake of phosphate results in remarkable reduction in pathogenic infection in mycorrhizal plant but not in non-mycorrhizal plant (bodker et al. 1998) . tomato plants already infected with rhizophagus irregularis are not colonized by the pathogen a. solani, whereas non-mycorrhizal plant is affected by the pathogen (fritz et al. 2006) . mixed action of arbuscular mycorrhizal fungi (amf) glomus intraradices and trichoderma harzianum as a biocontrol agent significantly reduces the damping off disease caused by rhizoctonia solani in the case of tomato seedlings (amer and seud 2008) . in order to combat parasitic (fungal, bacterial, viral, nematoidal, and insectal) infection like mammalian cells, plant cells also develop defense systems that mediate the release of low-molecular-weight and short-lived (generally 72-96 h of existence) antimicrobial compounds or molecules known as the phytoalexins (braga 1991; echiverri et al. 2010; paxton 1980) . these secondary metabolites help the plant to withstand biotic and abiotic stress (grayer and kukubun 2001) . most of them being lipophilic compounds can cross the plasma membrane and act inside the fungal cell causing cytoplasmic granulation of the infecting fungal cells, disorganization of the cellular components, rupture of the plasma membrane, and inhibition of the fungal enzymes and mycelial growth (cavalcanti 2005) . mode of action of phytoalexins against fungal pathogenesis varies from species to species (table 9 .1). metabolism of phytoalexin mediated by fungus involves the tendency for its increased polarity by addition of hydroxyl group (oxygenation), removal of methyl group (demethylation), etc. (jeandet et al. 2014) . muller and borger first enlightened the concept of phytoalexins almost 70 year ago (muller and borger 1940). the first reported case analyzed with the concept of phytoalexin was potato tuber infection by the different strains of causal organism of "late blight of potato," phytophthora infestans. this pathogenic fungus initiated the hypersensitive reactions that lead to the formation of some "plant secondary metabolite" that inhibited further infection of the same plant when infected with another strain of the same genus of phytophthora. muller and his coworker named this "principle" as "phytoalexins" that have protected the plant from secondary infection (deverall 1982) . accumulation of phytoalexins in the green plant tissue clearly indicates the presence of remarkable amount of fungal and bacterial infections in the host tissue (stoessl 1980) . phytoalexins are naturally occurring products secreted and accumulated temporarily by plants in response to pathogenic attack or abiotic stress and agents like heavy metal toxicity, uv radiation, and wounds on tissue (naoumkina et al. 2007 ). the inducer agent may be of two types, elicitor and elicitin. the elicitors are commonly the oligosaccharides from fungal cell origin (like hepatosaccharide from soja cell wall) (sharp et al. pezet and pont (1990) , adrian et al. (1997) , adrian and jeandet (2012) camalexin induction of the fungal programmed cell death (pcd) by apoptotic mechanisms et al. (2011) 1984). the elicitin types of molecules are generally a type of glycoproteins secreted by the fungal cells (cordelier et al. 2003) . reports on detailed investigations about phytoalexins have covered a very few families (leguminosae and solanaceae) of the green world (ingham 1982; kuc 1982) . though investigations on some selected number of species and genera are made from plant families including both monocotyledonous (amaryllidaceae, orchidaceae, poaceae) and dicotyledonous plants (apiaceae, asteraceae, convolvulaceae, chenopodiaceae, euphorbiaceae, linaceae, moraceae, piperaceae, rosaceae, rutaceae) and even gymnospermic taxa (ginkgoaceae) (coxon 1982) , cash crops like members of poaceae (focusing on maize and rice), vitaceae, and malvaceae (cotton) have been studied for their phytoalexin production (schmelz et al. 2014; langcake and pryce 1976; jeandet et al. 2010; sunilkumar et al. 2006) . though till date a lot of researches have already been performed regarding phytoalexins, a natural weapon against mycopathogens, but still to increase the fungitoxic effectivity of these stress metabolites, further advancement in design and genetic control is needed ). phytoalexin synthesis not only is dependent on pathogenic attack but also could be influenced by various abiotic factors such as temperature, humidity, and water availability ( fig. 9.1 ). there are evidences that different parts of the plant like leaves, flowers, stems, seeds, and root tubers are site of phytoalexin biosynthesis (mikkelsen et al. 2003) . different biochemical pathways are used for producing various types of phytoalexins. the three most common pathways include (i) the phenylpropanoic-polymalonic acid pathway, (ii) the methylerythritol phosphate (mep) and geranylgeranyl diphosphate (ggdp) route, and (iii) the indole phytoalexin (ip) pathway (jeandet et al. 2014 ). it is not always obvious that phytoalexins could be categorized not only by their chemical structure or biosynthetic pathway but also by their function and tissue specificity. examples include the occurrence of momilactone a on different plant parts of rice plant (lee et al. 1999; cartwright 1981) . momilactone a is known to be residing in rice husks and rice stems constitutively, but they are also a phytoalexin of rice leaves. further studies by toyomasu and his coworkers conclude that momilactone a is constitutively synthesized and oozed out from root of rice plants. still there is no sufficient data available to consider phytoalexins as ubiquitous throughout the whole plant kingdom. a lot of studies have revealed their complex biochemical synthetic machinery that involves their de novo synthesis, regulation, and mode of action (jeandet et al. 2013 ahuja et al. 2012 . regulatory mechanisms involve defense-related marker genes, calcium sensors, hormone signaling, phosphorylation cascades, and also their antipathogenic activity. there are reports on genetic engineering-mediated manipulation of phytoalexin production and increased disease resistance in the case of plants (delaunois et al. 2009; jeandet et al. 2012 jeandet et al. , 2013 . phytoalexins are secondary or stress metabolites that are produced when the host plant is infected with pathogenic fungus. phytoalexin-mediated defense response includes the expression of lytic enzymes such as chitinases and glucanases and a number of pathogenesis-related (pr) proteins, oxidizing agents, and lignification of cell walls (dixon and lamb 1999) . mode of action of phytoalexin involves the coordinated synergism between several defense factors for the effective inhibition of the fungal pathogen (purkayastha 2017; mansfield 1999) . in the case of sorghum plant, significant infection caused by fusarium proliferatum and fusarium thapsinum stimulates the production of 3-deoxyanthocyanidin, apigeninidin, and luteolinidin and also the concentration of defense-related proteins like peroxidases, β-1,3 glucanases, and chitinases that help to fight the pathogenic infection (huang and backhouse 2004 (koga et al. 1997; fukuta et al. 2007 ). there are several ways of blocking the fungal infection in host plant tissues by phytoalexin-mediated response. that includes inhibition of fungal spore on the leaf surface and inhibition during and after penetration to host cell (usman et al. 2018) . the occurrence of fungal germ tube on the leaf surface and diffusion of fungal metabolites through the leaf cells cause the accumulation of phytoalexins by the underlying cells and provide the first line of induced chemical defense (vanwees et al. 2003) . phytoalexins may be located on papillae or cell walls, thereby producing a localized, fungitoxic barrier to penetration (friend 2016) . examples include occurrence of fungitoxic (against erysiphe graminis) flavonoid (thought to be phytoalexin) on papillae of resistant barley leaves. phytoalexins are known to be solely produced as a result of induction or stimulus by external agents. fruitful evidences could be drawn regarding this fact. induction of disease resistance in plants is developed through the direct and indirect involvement of elicitors. extracts of fungal basidiocarp, essential oils of aromatic plants (walters et al. 2013) , and also synthetic chemicals like aminobutyric acid, salicylic acid, jasmonic acid, and acibenzolar-s-methyl ( (matiello and bonaldo 2013) , hymenolobium petraeum, qualea albiflora, and corymbia citriodora (matiello et al. 2016 ) that act as the elicitors of deoxyanthocyanidins and glyceolin production. homeopathic preparations of species of calcarea (c. citriodora and calcarea carbonica), essential oils of eucalyptus globulus (telaxka et al. 2014; oliveira et al. 2014) , and mild concentrations of salicylic acid (durango et al. 2013 ) are major elicitins of pistain production and accumulation in cotyledons of common bean (phaseolus vulgaris). silicon-mediated enhancement of disease resistance by peroxidase (pox), polyphenol oxidase (ppo), chitinases (chi), β-1,3-glucanases (glu), and phenylalanine ammonia-lyase (pal) is found in the case of leaf spot of cotton plant caused by ramularia areola (curvêlo et al. 2013 ). southern amazonian amphibian family bufonidae represents the true toads, and their cutaneous secretions are of diverse source of bioactive compounds which can be fruitful as new chemical weapons for agrochemical development. use of elicitors in the case of crop protection nowadays is becoming a very popular method of inducing response which are proved to be durable and broad-spectrum disease control mechanism where the plant's own resistance is used. a group of seven brazilian scientists (deice et al. 2019) evaluated the possibilities of methanolic extracts of cutaneous secretions of two species of bufonidae, rhaebo guttatus and rhinella marina, on synthesis of phytoalexins named glyceolin (soybean plant), deoxyanthocyanidins (sorghum plants), and phaseolin (mung plant) in soybean cotyledons, sorghum mesocotyls, and bean hypocotyls, respectively. there is a direct relationship between the phytoalexins production and defense ability of the host plant against the fungal pathogenesis. studies reveal that when the phytoalexin glyceolin is produced in higher amount in the soybean plant (cultivar tmg 132 rr) as a result of methanolic extracts of amphibian's (r. guttatus) cutaneous secretion (at a concentration of 0.2 mg/ml), stimulates the enzyme β-1,3-glucanase that can cause the hydrolysis of the fungal cell wall along with other defense-related enzymes (chitinase) is also produced in higher amount, but when suppression of glyceolin occurs, that particular enzyme is also not produced. there are evidences in the case of glycine max that the effectivity of phytoalexins varies from cultivar to cultivar. application of r. marina (amphibian) methanolic extracts induced glyceolin production in tmg 132 rr and monsoy 8372 cultivars ipro but did not induce tmg 132 rr cultivars to synthesize these defense-related compounds. less toxicity of phytoalexins than chemical fungicides is the reason for their universal acceptance. for over 75 years, phytoalexins have been a detailed area of study for its antimicrobial activity, especially antifungal properties. several investigations include the in vivo bioeffectivity of the phytoalexins against serious plant pathogenic fungi (table 9 .2). phytoalexin synthesizing genes have also been genetically modified to cope up with the pathogenic evolution. still reports are there that include examples of cruciferous phytoalexins detoxification by fungal enzymes (pedras and abdoli 2017) . modification of pathogen to overcome phytoalexinmediated damage includes curved germ tubes as a result of asymmetric growth of the germ tube. phytoalexins are natural products of diverse chemical nature, for example, alkaloids, coumarins, isoflavonoid (coumestans, isoflavans, isoflavones, isoflavanones, pterocarpans, pterocarpenes), lignans, polyacetylenes, pterocarpons (pisatin, phaseolin, glyceollin, medicarpin, and maackiain), terpenes, and non-isoflavonoid compounds (furanoacetylenes and stilbenes) ( fig. 9 .2) (grayer and kokubun 2001) . both in vitro and in vivo fungicidal activity are shown by sakuranetin (rice phytoalexins) against the blast fungus (hasegawa et al. 2014 ). reduction of green mold (caused by penicillium digitatum) infections is achieved by the action of coumarin type of phytoalexin (scopoletin) of orange (sanzani et al. 2014 ). the loss of apples production caused by penicillium expansum and accumulation of patulin is minimized by the action of phenolic phytoalexins like resveratrol, scopoletin, scoparone, and umbelliferone (sanzani et al. 2009 ). in the case of medicago sativa (alfalfa), the isoflavonoid 7-o-methyltransferase provides increased resistance against phoma medicaginis by synthesizing maiackiain (he and dixon 2000) . for soybean plants, transformation of resveratrol to pterostilbene 7, langcake and pryce (1976) , coxon (1980) , and harding and heale (1981) (continued) (zernova et al. 2014) . scientists have proven that not only fungal infection acts as the stimulus for phytoalexin synthesis but also the hormone levels; phosphorylation cascades play a major role in this purpose. cytokinin overexpression in nicotiana tabacum is directly associated with its resistance against p. syringe by higher concentration of capsidiol and scopoletin (grosskinsky et al. 2011 .) the fungitoxicity of the phytoalexin could be enhanced by methylation or presence of electron-attracting groups on aromatic rings that is directly involved in affinity with membrane proteins being an uncoupler of ets system. endophytes are a type of hidden beneficial microorganisms that reside within the host plant causing no visible disease symptoms and syndrome and promote the plant to maintain its existence in typical harsh conditions. sometimes they could be latent pathogens at a very distant path of the host's life cycle but are simply a unique area of research where plant science and their microbial association get new definition. endophytes have been a constant and reliable source of exploration of bioactive compounds, but extensive search has not been performed till date, and that has given the endophyte biologists a great opportunity to search endophytic fungal and actinobacterial flora for the establishment of novel bioactive compounds. selection of plant for endophytic isolation is the most vital part of this study. exploitation of the proper isolates accelerates this search and opens up new angle of research. the search for uncommon products of agrochemical importance is a common demand of todays' world. the safer the antifungal agents become, the more it is well accepted in the scientific community as well as agricultural market. in general, the screening of thousands of natural products ends up giving only one commercial product. so indeed it's a tough job to end the search of new antibiotics with a hopeful result. a total of 6 out of 20 of the popular prescribed medicines are of fungal origin, and it is a fact that 5% of the fungi have been described till date (hawksworth 1991 (hawksworth , 2001 . so fungi serve as a continuous dependable source of new natural products. the intelligent screening procedure includes the selection of fungal flora of endophytic sources to open up the untapped potential of secondary metabolites synthesized by fungi. microorganisms grown in the petri plates or culture broth constitute minimal growth medium needed for their survival. any kind of stress or transfer of microorganisms on selective media acts as a stimulation for production of their secondary bioactive compounds. these secondary metabolites are produced for their survival in odd environments and strictly act as the selection force for the expression of their antimicrobial-producing genes. these crude by-products of microbial cultures are filtered and purified for their industrial, medicinal, and agricultural exploitation. soil microorganisms have been exploited for a long time for production of antibiotics, but microorganisms inhabiting plants are a new source in that respect. plants are selected usually with potent medicinal applications. here the knowledge of ethnobotany and folk taxonomy contributes a lot in this selection procedure. a strong literature survey supports the plant selection. the plants are surface sterilized and plated in nutrient-less solid plates. the fungi emerge out from different explants using the decaying plant parts as their primary growth substance. the isolates are identified by microscopic structures focusing on their conidial morphology, spore sculpturing, and colony characters. confirmatory identification includes 18s rrna analysis. endophytic fungi are tested for their antifungal activity against phytopathogenic fungi by one-to-one inhibition assay or antagonistic test ( fig. 9 .3). two agar portions containing fungal hypha of endophyte and pathogen are placed on opposite sides of the plate. if the growth of pathogenic one is arrested partially or completely, that endophytic isolate is marked as antifungal agent and selected for further studies. another way of screening includes separating the agar plate into two equal halves, and two fungi are placed on two separate sides of the discontinuous plate. this test aims to screen the endophytes that produce volatile antifungals. if the isolate is potent enough to produce volatile organic compounds with fungi static or cidal activity, this will cease the growth of the pathogenic strain. then that isolate would be qualitatively and quantitatively measured for their volatile emissions using gc-ms as the master equipment ( fig. 9 .4). liquid extracts of endophytic fungi are also tested for antifungal potentials by agar well-diffusion method. the fungal extract having antibiotic property shows clear zone of inhibition of growth of the pathogenic fungus surrounding the area of application of that fungal liquid. the potent isolate will be mass cultured, and the bioactive molecules will be extracted using organic solvents like ethyl acetate, ethyl ether, and n-hexane. steps include purification of that fungal extract by column chromatography, detection of the compound by thin-layer chromatography, and analysis of compounds by hplc and mass chromatography. field experiment includes the synergistic effect of a pure compound with mixture of natural compounds, and the effectivity of a newly applied antifungal agent strictly depends on the host plant and pathogenic microorganism's interaction, environmental condition, and development of drug resistance by that organism. application of pellets soaked in fungal extracts also is a method of determination of antifungal activity. secondary metabolites are itself diverse in nature. a variety of bioactive secondary metabolites are produced at significant concentrations by the endophytic microbial flora. the major components include quinones, phenols, phenolic esters, steroids, terpenoids, cytochalasins, benzopyranone, alkaloids, isocoumarins, and chromones. till date, a large number of plants have been studied for their endophytic flora as antifungal agents (table 9 .3). alkaloid was the first ever reported insecticidal bioactive product. cryptocin was isolated from endophyte of tripterygium wilfordii, a plant of celastraceae family. the inner barks of the stem were used as explant, and cryptosporiopsis cf. quercina was isolated as a potent endophyte active against pyricularia oryzae and some other phytopathogenic fungi (li et al. 2000) . colletotrichum sp. produces 6-isoprenylindole-3-corboxylic acid having inhibitory action against phytophthora capsici, a pathogen of cucurbitaceae, fabaceae, and solanaceae, and also other phytopathogens rhizoctonia cerealis and gaeumannomyces graminis var. tritici, a common pathogen of poaceae family . epoxycytochalasin h and cytochalasins n and h were isolated as chloroform and methanolic extracts of (fu et al. 2011) . a lot of endophytes have been explored for their antifungal production, but only a few of them were positive for antifungal metabolites categorizing in alkaloids. the common alkaloids acting as the antifungal agents of endophytic fungal origin are gliotoxin, cryptocanadin, tyrocidine a, fumigaclavine c, fumitremorgin c, 1-n-methyl albonoursin, and phomapsichalasin. the terpenoids, usually called isoprenoids, are large and diverse group of naturally occurring organic compounds derived from terpenes that are multicyclic. sixty percent of all the known natural products are terpenoids in nature. some endophytic fungicidal products are of terpenes by their native chemical structure. endophytic isolates (hormonema sp.) of gymnospermous plant juniperus communis were reported to be antifungal producers of a triterpene glycoside enfumafungin (pelaez et al. 2000) . known antifungal sterols of endophytic origin are 3β-hydroxyergosta-5-ene, 3-oxoergosta-4,6,8,22-tetraene, etc. the sterols are strong inhibitors of helminthosporium sativum (present name: bipolaris sorokiniana), the asexual stage of cochliobolus sativus, a common root rot pathogen of wheat and barley crops which also infects leaf and stems of poaceae plants . sesquiterpenes are reported to be the growth inhibitors of cladosporium phlei (causal organism of leaf spot disease of timothy grass, phleum pratense). this is a unique example where the host plant (phleum pratense) itself harbors the endophyte (epichloe typhina) that inhibits the growth of its leaf spot pathogen (cladosporium phlei). from the point of view of organic chemistry, isocoumarins are defined as the isomer of coumarin where the orientation of the lactone is reversely arranged. zhang and his coworkers in the year 2008 isolated an endophytic fungus named microdochium bolleyi from fagonia cretica (also known as virgin's mantle of zygophyllaceae family), a herb of semiarid regions of gomera. isocoumarins were identified as the active compounds having antifungal activity against microbotryum violaceum (previously known as ustilago violacea), an obligate parasite of basidiomycete group and a common infectant of members of caryophyllaceae causing smut of anther. the four isolated and identified isocoumarins are monocerin, 12-oxo epimers of monocerin, and open-ring derivative compounds of monocerin. the compounds are obtained as mixtures by column chromatography followed by sephadex lh-20 chromatography techniques. preparative tlc further differentiated the four compounds. monocerin and its analogues were previously reported as antifungal compounds from fungal sources of drechslera monoceras, exserohilum monoceras, helminthosporium monoceras, exserohilum turcum, and fusarium larvarum (aldridge and turner 1970; robeson and strobel 1982; grove and pople 1979; claydon et al. 1979) . these secondary metabolites act on pathogens by interfering stages of divisional phases of cell cycle. the second isocoumarin was colorless oil. the third and fourth one are represented by the empirical formula of c 16 h 20 o 7 and c 16 h 22 o 7 . the fourth one is structurally correlated to fusarentin 6,7-dimethyl ether. both the compounds are of heptaketide in their origin, and it is revealed that fusarentins are the probable precursors of the active compounds monocerins (scott et al. 1984; axford et al. 2004 ). dihydroisocoumarins, mellein (an isocoumarin derivative), (r)-7-hydroxymellein, and fonsecinone were reported from species of xylaria (endophyte of piper aduncum), pezicula, penicillium (alibertia macrophylla), and aspergillus (cynodon dactylon), respectively (oliveira et al. 2011; schulz et al. 1995; song et al. 2004 ). phenols (popularly known as phenolics) represent a class of chemical compounds characterized with a hydroxyl group attached to an aromatic hydrocarbon group. phenol (or carbolic acid) is a colorless crystalline solid, aromatic compound having benzene rings. they are predominantly found in the plant kingdom as a response to stress and are of utmost importance. endophytic culture extracts are also known to be rich sources of phenolics; usually they are directly proportional to the antioxidative property of any fungal isolate, but in some particular cases, they are characterized with their antifungal potentials against phytopathogenic fungus. usually the liquid culture extracts of the endophytic isolates are subjected to solvent extraction using ethyl acetate, n-hexane, ethyl ether, etc. those organic solvents are believed to extract the phenolics from the water-based culture broth. those extracted compounds are further screened for their antifungal efficiency. ethyl acetate extracts of endophytic phoma sp. are reported to contain tetralone metabolites (derivatives of α-tetralone, 3,6,7-trihydroxy-α-tetralone) inhibiting the growth of two common broad phytopathogenic fungus fusarium oxysporum and rhizoctonia solani. griseofulvin is known to be the first antifungal compound isolated from penicillium griseofulvum. later it is isolated from several species of fungi including endophytic penicillium canescens and xylaria sp. (member of xylariaceae family). griseofulvin from endophytic p. canescens of popular chinese medicinal plant polygonatum cyrtonema (polygonaceae) showed strong inhibitory effectivity against phytopathogenic botrytis cinerea, sclerotinia sclerotiorum, colletotrichum orbiculare, and didymella bryoniae . other than penicillium, endophytic xylaria sp. isolated as an endophyte of abies holophylla yields griseofulvin and dechlorogriseofulvin for in vitro and in vivo effectivity against pathogenic magnaporthe grisea, corticium sasakii, blumeria graminis (park et al. 2005) . the ascomycete fungus pestalotiopsis is known to be a common plant pathogen but also has been reported many times because of their endophytic existence in the host plants. the two common species pestalotiopsis microspora (host: tropical plant terminalia morobensis) and p. fici are reported to be producing antifungal metabolites isopestacin and pestalofones d-e (harper et al. 2003; liu et al. 2009a, b) . chlorogenic acid and colletotric acids are antifungal phenolics of colletotrichum gloeosporioides and sordariomycetes sp., respectively zou et al. 2000) . they were isolated from medicinal plants of china (artemisia mongolica and eucommia ulmoides) and effective against fungi imperfecti helminthosporium sativum. orcinol is used for the production of a dye called orcein used randomly for the staining of cells and chromosomes. orcinol is popularly known for its antifungal activity too and has been isolated as a product of endophytic origin of penicillium sp. from alibertia macrophylla (a plant of rubiaceae) showing bioactivity against cladosporium cladosporioides and cladosporium sphaerospermum (oliveira et al. 2014) . endophytic phomopsis sp., dothiorella sp., and diaporthe sp. have also been tested for their antifungal production and antifungal compounds that were detected (brady et al. 2000; xu et al. 2004; huang et al. 2008 ). volatile organic compounds (vocs) are said to be a type of organic low-molecularweight carbon-containing small compounds (up to c20) that have a high vapor pressure with low molecular mass (100-500 daltons) at room temperature. the high vapor pressure results from a low boiling point of that chemical compound, which causes a huge quantity of molecules to evaporate from the liquid, solid, or semisolid form of the compound and gets released into the surrounding environment. the endophytes are unique in their volatile emissions. the term mycofumigation that is very much popular with the treatment of agricultural phytopathogens is actually the output of vocs that originated from endophytic isolates. the first ever reported volatile antibiotic producer was muscodor albus (xylariaceae family), an endophyte of guazuma ulmifolia (a plant of sterculiaceae family collected from tropical forest of sw ecuador), isolated by gary strobel and his co-workers ). the major compounds isolated by gcms are known to be involved in antifungal, antibacterial activity. compounds include butanoic acid, 2-methyl-; butanoic acid, 3-methyl-; 2-butenal, 2-methyl-; butanoic acid, 3-methylbutyl ester; 3-buten-1-ol, 3-methyl; guaiol; 1-octene, 3-ethyl-; formamide, n-(1-methylpropyl); azulene and naphthalene derivatives; caryophyllene; phenylethyl alcohol; acetic acid, 2-phenylethyl ester; bulnesene; and various propanoic acid, 2-methyl-derivatives. these compounds were tested against a number of phytopathogenic fungi (botrytis cinerea, mycosphaerella fijiensis, pythium ultimum, phytophthora cinnamomi) showing partial or complete death or growth inhibition of those pathogens after 2 or 4 days of incubation. muscodor albus was reported from a diverse type of host plants, i.e., myristica fragrans, terminalia prostrata, cinnamomum zeylanicum, and ginkgo biloba, by several workers (worapong et al. 2001; sopalun et al. 2003; ezra and strobel 2003; mercier et al. 2004; ezra et al. 2004a, b; atmosukarto et al. 2005; lacey and naven 2006; lacey et al. 2009; strobel et al. 2007; banerjee et al. 2010a, b; corcuff et al. 2011; alpha et al. 2015) . the mycofumigants are effective against pathogen fusarium culmorum, causal agent of seedling blight, foot rot, ear blight, stalk rot, and common rot of cereals. sexual stage (teleomorph) of glomerella cingulata, a fungus of glomerellaceae, is a potent pathogen causing anthracnose-like symptoms of water-soaked, sunken spots and necrotic lesions on fruits of forest trees. this phytopathogen is strictly inhibited by the volatile emissions of this novel endophyte. banerjee et al. (2010a, b) first reported muscodor albus strain gba from the usa as an isolate of ginkgo biloba (first isolate of m. albus from g. biloba) and tested the biological efficacy of its volatile mixtures against agricultural pathogens and also evaluated its promises to be used as a commercial mycofumigant agent for controlling the fungal diseases in storage fruits and vegetables, that is, agricultural productions and during food transportation. the strain gba in comparison to other strains of muscodor e6 and cz620 completely inhibits and potentially kills the member of phycomycetes, pythium ultimum after 2 days of exposure of the mixture of volatiles. the organic compounds include alcohols, acids, esters, ketones, and lipids as their active components. 1-butanol, 3-methyl-, acetate was found in significant quantities. vitrine, a terpenoid, was first isolated from muscodor albus strain gab. the volatile mixture is artificially produced by the mixture of the pure compounds, and that mixture is again checked for antifungal activity. a positive mycocidal or mycostatic effect similar to the effect of endophyte's volatile emission will confirm establishment of the endophyte and its mixture as the biocontrol or antifungal agent. myrothecium inundatum, an endophyte of herbaceous acalypha indica (euphorbiacea member collected from northeastern part of india), produces unique mixture of volatile components having 3-octanone, 3-octanol, 7-octen-4-ol, sesquiterpenes, organic acids, methyl esters, naphthalene, 2-octanoic acid, heptanoic acid, etc. this endophyte produces foam in its liquid culture predominant with long-chain carbon compounds like octane, 1,4-cyclohexadiene, 1-methyl-and cyclohexane, and 1-ethylpropyl. (meshram et al. 2013 (meshram et al. , 2017 suwannarach et al. 2015; saxena et al. 2015; suwannarach et al. 2010 suwannarach et al. , 2012 suwannarach et al. , 2013 kudalkar et al. 2012; mitchell et al. 2010; worapong et al. 2002; daisy et al. 2002; siri-udom et al. 2016 postharvest fungal disease is one of the prime causes of agricultural loss of crops. use of biological agent to minimize this loss is one of the vital targets of agriculturalists, horticulturalists, and plant biologists. several chemical agents have been already tested for practical applications, but endophytes are less explored organisms in this arena. volatiles from endophytic source open up new scope of utilization of unique mixtures of chemicals to be used as mycofumigant agents. a large number of endophytes have already been screened for their postharvest disease management ability (table 9 .4). the volatiles of the endophyte could be considered as the natural fungicides. muscodor vitigenus, an endophyte of hevea brasiliensis, was analyzed in gc-ms for their volatile production. the isolates produce a unique mixture of myroxylon balsamum 1, 4-cyclohexadiene, 1-methyl-; 1,4-pentadiene and cyclohexene, 1-methyl-4-(1methylethenyl)-; alkyl alcohols starting with 1-butanol-3-methyl, 1-propanol-2-methyl, cinnamomum bejolghota. this isolate was known to produce azulene, a new compound detected first from any muscodor species. this species was tested in vitro and in vivo for antifungal activity against a common worldwide devastating pathogen rhizoctonia solani (causal agent of damping off). the vocs produced by this fungi include (s)-(+)-5-methyl-1-heptanol; ethyl acetate; propanoic acid, 2-methyl-, methyl ester; cis-2,4-dimethylthiane; s,s-dioxide; cyclopentane; butanoic acid, 2-methyl-, methyl ester; 1-butanol, 3-methyl-, acetate; β-humulene; azulene, 1,2,3,5,6,7,8,8a-octahydro-1,4-dimethyl-7-(1-methylethenyl)-; 1s-(1.α., 7.α., 8a.β); and eudosma-4(14),11-diene 1,1,1,5,7,7,7-heptamethyl-3,3-bis(trimethylsiloxy) tetrasiloxane. rhizoctonia solani-infected seedlings were treated with volatile mixtures to assess the mycofumigation property. in vivo experiment was conducted on four seedlings of bird pepper, bush bean, garden pea, and tomato. it was concluded that 30 gm of muscodor cinnamomi prepared on rye grain solid media is the minimum dose required for inhibition of rhizoctonia infection and total control and elimination of damping off symptoms. muscodor cinnamomi-infected soil does not show any seed germination inhibition in comparison to rhizoctonia solani-infected soil. so it is a type of pioneer study of using endophytic species as potent agents of fumigation and biocontrol. candida intermedia strain c410 (saccharomycetaceae) was isolated as an endophyte of strawberry (fragaria ananassa), and the volatile emission was known to be a mixture of 49 organic compounds including esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes of which 1, 3, 5, 7-cyclooctatetraene and 3-methyl-1-butanol were the most dominant (huang et al. 2011 ). volatiles of strawberry endophyte were itself useful as postharvest control agent for the host plant against botrytis fruit rot. other compounds include 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester that were found to be extremely inhibitory to conidial germination (reproductive growth) and also vegetative (mycelial) proliferation of b. cinerea. when the fruits are exposed to c. intermedia synthetic volatiles or itself to the fungus, the incidence of botrytis fruit rot reduces significantly. strawberry fruits inoculated directly with the endophyte also remain disease-free. so mixtures of candida intermedia c410, the unique natural products, are useful as mycofumigation technique or for postharvest disease management by biological control policies. tangerine fruit (citrus tangerine), the commercial citrus crop of northern thailand, faces huge postharvest losses due to pathogenesis of green mold (penicillium digitatum). the pathogen is the prime cause of worldwide deterioration of tangerine fruits by mycopathogenesis. out of 32 detected compounds, the most predominant were 2-methylpropanoic acid and 3-methylbutan-1-ol. other compounds include carbitol, octanoyl chloride, azulene, 3-methylhexane, 2-methylpropan-1-ol, 2,3-butanediol, caryophyllene, 2-methylbutyric acid, ethyl 2-hydroxyproponate, etc. the pathogen was treated both in vitro and in vivo for their inhibition by endophytic volatile components. in both cases, pathogen growth was restricted. during transportation of the fruits, fungus causes huge crop loss by infecting the fruits; when fruits were inoculated with 30 gm of rye grain culture of m. suthepensis (1 month old), the disease development is ceased. so it is a classic example of mycofumigation by the biocontrol agent of tangerine fruit for the control of rot lesions caused by p. digitatum infection. the in vivo application requires the proper surface sterilization (using sodium hypochlorite) of the targeted parts where the inoculation is going to be done, for example, fruit, stem, root, and leaf. usually infection on fruits for assessing the biocontrol potential is the most common and popular method. the seeds will be washed in distilled water, and using sterile needle, uniformly the whole area would be done, and the whole area would be infected or inoculated with the endophytic liquid extracts containing spore suspensions. muscodor albus vocs are potent enough to cause a significant reduction of in vitro spore germination of the tilletia species t. horrida, t. indica, and t. tritici. endophytic nodulisporium spp., trichoderma spp., phomopsis spp., and oxyporus latemarginatus are reported to produce vocs that inhibit mycelial growth of phytopathogenic fungi (lee et al. 2009; park et al. 2010; ajith and lakhsmidevi 2010; amin et al. 2010) . black sigatoka disease (also known as leaf spot or black leaf streak disease) of banana (musa paradisiaca) is caused by mycosphaerella fijiensis (ascomycete fungus). this phytopathogen is inhibited by the volatile emissions of muscodor sutura, an endophytic isolate of prestonia trifidi. the volatiles are effective also against ceratocystis ulmi, the causal agent of dutch elm disease of american elm (ulmus americana). the volatile mixtures include thujopsene, chamigrene, isocaryophyllene, and butanoic acid, 2-methyl-that are potent inhibitors of the common anthracnose pathogen of cucumber, muskmelon, and watermelon (members of cucurbits), colletotrichum lagenarium. so this unique endophyte and its chemical mixtures are potent mycofumigants and ensure crop protections against destructive pathogens like c. ulmi and c. lagenarium, sclerotinia sclerotiorum (causing white mold, cottony rot, water soft rot, stem rot, drop, crown rot, and blossom blight diseases of the host), and also phytophthora palmivora (oomycete fungi), the causal agent of bud root of palms and areca nut predominantly occurring in regions of south india (kudalkar et al. 2012) . liarzi and his coworkers tested the biological control efficacy of the endophytic daldinia cf. concentrica, isolated from olive tree (olea europaea l.) of israel against 18 phytopathogens, and the unique mixtures of 27 volatile were effective against the phytopathogenic mycelial growths. the mixtures include a variety of organic compounds: 3-methyl-1-butanol, 2-methyl-1-butanol, 1-methyl-1,3-cyclohexadiene, 1-methyl-1,4-cyclohexadiene, 4-heptanone, isoamyl acetate, 4-heptyn-2-ol, 2-octenal, octanal, β-elemene, α-guaiene, β-selinene, α-selinene, α-bulnesene, germacrene a, etc. the unique mixtures having broad-spectrum antifungal property could be used for fumigation for eliminating the pathogenic infections of aspergillus niger (mold-causing organism on fruits of economic importance). so the endophytic d. cf. concentrica opens up opportunities for fungal disease control in food and agricultural industries (liarzi et al. 2016) . nodulisporium sp. strain gs4d2ii1 (hypoxylon anthochroum) and hypoxylon anthochroum strain blaci are potent enough to be used as biopesticide against fusarium oxysporum, a common contaminant of solanum lycopersicum var. cerasiforme (cherry tomato) causing a great percentage of crop loss globally. six vocs of alcohols' mixture, phenylethyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, eucalyptol, ocimene, and terpinolene, were detected and applied together with synergistic effect and individually both in vitro and in vivo. inoculation of pathogen on the cherry tomato fruits yields significant reduction in fusarium contamination. both agar dilution techniques and gas test were done to assess the in vitro antifungal activity, and the endophytic volatile mixtures were effective in both the cases. volatiles kill the pathogens probably by interfering cell membrane permeability, hyphal morphology, and respiratory activity of the pathogenic fusarium oxysporum. so it is a great opportunity to use the unique mixture of volatile organic compounds of the endophytic isolate to reduce the crop loss caused by the pathogenic infection on the commercially valuable plant of cherry tomato worldwide. endophytic phoma sp. (didymellaceae) and phomopsis sp. (valsaceae) were isolated from larrea tridentata and odontoglossum sp. singh et al. 2011) . the volatiles detected are effective against phytopathogens verticillum sp., ceratocystis sp., cercospora sp., sclerotinia sp. sclerotinia sp., and botrytis sp. algae are diverse group of autotrophs and the leading producers of o 2 in the ecosystem. they range from prokaryotic unicellular to eukaryotic complex multicellular forms involved in the marine and terrestrial food chain. antifungal activity of the seaweed (members of phaeophyceae and rhodophyceae) is a major weapon for natural fungicides along with their antibacterial, anti-protozoan, and antiviral activities. algal seaweeds are potent holders of large number of secondary metabolites including phenolics, terpenes, alkaloids, and lectins which are not directly involved in photosynthesis and reproduction and thus fall under the category of secondary metabolites. they are common antimicrobial of algal origin that act on the target organisms by altering the microbial cell permeability accompanied with the loss of internal macromolecules or sometimes interfere with the membrane function causing cellular disintegrity ultimately leading to cell death (abu-ghannam and rajauria 2013). several studies include antifungal activity of algal members against human pathogens; a very few studies include their efficacy against plant pathogens (cheung et al. 2014; singh et al. 2007; stirk et al. 2007; padmakumar and ayyakkannu 1997; ismail et al. 2014; genovese et al. 2013; lopes et al. 2015 ). padmakumar and ayyakkannu tested 80 species of algae against a variety of bacterial and fungal pathogens. out of the all screened organisms, 70% exhibited antibacterial efficiency, and only 27.5% inhibited fungal growth. polysaccharides found in the cell wall and deposited in terms of storage food from red and brown algal sources include ulvans (obtained from ulva sp.), alginates and fucans (from fucus sp.), laminarin (laminaria sp.), and carrageenans that can induce defense responses in plants against phytopathogens by pathogen-associated molecular patterns (maps) and are capable of inducing plant resistance (vera et al. 2011) . polysaccharides stimulate regular cellular changes associated with pathogen perception and defense activation by change in ca 2+ concentration and burst due to oxidative stress activation of salicylate, ethylene, and jasmonate biosynthetic pathways and by activating pathogenesis-related proteins (prps) (jaulneau et al. 2010; zhao et al. 2012) . as a result of the depolymerization of the polysaccharides, the obtained oligosaccharides induce protection against a variety of fungal, viral, and bacterial diseases by accumulation of the antimicrobial compounds in the cell. algal polysaccharides as an alternative weapon over the synthetic agricultural drugs for controlling plant disease have been widely studied (stadnik and freitas 2014; hahn et al. 2008 ). brown algae laminaria digitata, a genus of phaeophyceae, is commonly called seaweeds and known to be the potent producers of kelp, an iodine-rich substance needed for the normal functioning of thyroid gland. laminaria produces laminarin, glucan polysaccharide-containing 1,3-linked β-d-glucose moiety, a reserve food material found on the vacuoles of the vegetative cells of this genus. β-glucans are involved as a major part of daily diet and obtained from the brands of common cereals. they are involved in the defense responses of agricultural crops like tomato (lycopersicon esculentum), eggplant (solanum melongena), pepper (piper nigrum), watermelon (citrullus lanatus), grape (vitis vinifera), apple (malus sp.), and pear (pyrus communis). elicitation of defense response by laminarin against causal agents of gray mold (botrytis cinerea) and downy mildew (plasmopara viticola) in grapevine plants remarkably suppresses their infection up to 55% and 75%, respectively (copping et al. 2004 ). so, natural product from brown algae laminaria sp. known as laminarin or laminaran can act as the biofungicide or biocontrol compounds. use of laminarin significantly reduces the mycelial growth and aflatoxin production in aspergillus flavus and ensures its use as a fungicide (liangbin et al. 2012) . the advantage of using laminarin over other products is that as it breaks down finally to glucose molecules, it has no maximum residue limit (mrl) on the plant treated with this product. so, there is no need of preharvest interval constraint. this has been a prime cause why laminarin has substituted five popular fungicides involved in the treatment of apple scab (venturia inaequalis) in france (mery et al. 2013 ). this phyto-pharmaceutical is used widely in france and some countries of europe in the name of vacciplant (major active constituent is laminarin). laminarin has broad-spectrum applicability on fire blight of apples and pears in greece, france, belgium, switzerland, portugal, and also morocco. it is effective for apple scab disease in france and belgium and for curing storage diseases of apples caused by gloeosporium sp. in belgium. laminarin comes out as a fungicide of natural origin after being eligible in 33 tests between 2001 and 2011 in several parts of europe, for example, france, belgium, italy, and poland, on natural contamination of orchards on several sensitive strains of scab fungus including golden delicious, golden smoothie, read cheaf, galaxy, gala, and pink lady. laminarin is applied widely against secondary scab (to minimize secondary scab during summer and up to harvest) as a result of its uniqueness in its mode of action. it does not involve cell death of the host plant or hypersensitivity induction in the host organism but rather stimulates plants' natural resistance (klarzynski et al. 2000) . aziz et al. (2003) reported its effectiveness in tobacco plants, wheat, strawberries, apples, and vines. the application of laminarin and alginate reduced the development of wilt symptoms caused by verticillium dahliae on olive twigs, stimulating its phenolic metabolism (salah et al. 2018) . moreover, alginates reduced pathogen growth in vitro. laminarin induces the release of h 2 o 2 in cells of tobacco plants and leads to the increase in pal activity (phenylalanine ammonia-lyase) and causes the accumulation of pr-1, pr-2 (glucanase), pr-3 (chitinase), and pr-5. concerning red algae polysaccharides, carrageenans induced protection against a broad range of pathogens such as tobacco mosaic virus (tmv), b. cinerea, and e. carotovora on tobacco (vera et al. 2011) . again on tobacco, mercier et al. (2001) showed that carrageenan infiltrated the leaves and increased the expression of genes coding for a sesquiterpene cyclase involved in the synthesis of the antimicrobial terpenoid capsidiol, pr-3 proteins (basic chitinases), and proteinase inhibitor with antipathogenic activity. an adequate percentage of growth and spore germination inhibition of botrytis cinerea was mediated by the hexane extracts of laminaria digitata and undaria pinnatifida. porphyra umbilicalis, laverbread, is an edible seaweed (corato et al. 2017) . other than b-glucan polysaccharides (laminarin) of laminaria, other secondary metabolites (phenols, terpenes) of phaeophycean algae (sargassum sp.) showed effectivity against common pathogens fusarium solani, rhizoctonia solani, aspergillus spp., fusarium oxysporum, penicillium spp., and botrytis cinerea (khallil et al. 2015; ibraheem et al. 2017; mabrouk et al. 1985; liu et al. 2014 ). cyanophycean blue-green algae are abundant all over the world and ranging from pond ecosystem to oceanic system. though they have been reported to produce a large number of toxins and involved in death and disease of cattle and human being, they are of serious interest from the point of view of natural fungicidal products. drawing the similarities with bacteria, they are characterized with a mucilaginous or gelatinous sheath composed of polysaccharides which are the weapon against fungal pathogenesis. cyanobacterial polysaccharides (pol) show higher disease resistance against b. cinerea when they are applied on the intact fruit (preharvest conditions when fruit is attached to the plant) rather than the fruit detached (postharvest conditions) from the plant (zheng et al. 2011; feliziani et al. 2015; yao and tian 2005) . polysaccharides are involved in elicitation as elicitors for development of local and systemic disease resistance and expression of defense enzyme synthesis, for example, chitinases and glucanases that are involved directly in antifungal responses (paulert et al. 2009; reymond and farmer 1998; sharma et al. 2014) . water extracts of common bga anabaena sp., ecklonia sp. (common edible marine algae of japan and korea), and corallina sp. (hard seaweed of corallinaceae family) exhibit antifungal activity against podosphaera xanthii (causal agent of powdery mildew of cucurbits) on zucchini plant, cucurbita pepo, of cucurbitaceae (roberti et al. 2015 (roberti et al. , 2016 . in the recent past, fungi inhibitory ability of algal members has been reported by several workers (righini et al. 2018; corato et al. 2017; khallil et al. 2015; ibraheem et al. 2017) . in vitro growth inhibition of aspergillus oryzae and penicillium notatum has been seen by cyanophycean anabaena laxa (frankmölle et al. 1992) . devastating plant pathogens pythium sp., fusarium sp., and rhizoctonia sp. were restricted by extracts of anabaena sp. (moon et al. 1992; manjunath et al. 2010) . the use of bga extract as the growth inhibitor of pathogenic chaetomium globosum, cunninghamella blakesleeana, aspergillus oryzae, rhizoctonia solani, fusarium sp., pythium sp., and sclerotinia sclerotiorum is reported. the extracts of phormidium fragile and nostoc muscorum (rizk 2006 bryophytes, the simplest member of the broad umbrella of embryophyta, are situated between algae and pteridophytes, are known to be plant amphibians growing in the marshy or shady habitat, and require water for their fertilization and for the perfect swimming motility of their sperms. they have been evaluated for their antimicrobial activity for a long time. it has been proved that these cryptograms are rich source of bioactive secondary metabolites and can easily be exploited as an alternative source of fungicidal compounds. as they grow in marshy habitats and can protect themselves from biotic (ultraviolet rays, heat stress, and predation) and abiotic stress (fungal or bacterial attack), they are store house of diverse bioactive chemicals (xie and lou 2008) . members of hepaticopsida and mosses (the evolved members of bryophytes) are known to possess antifungal activity and are rich source of flavonoids, terpenoids, bibenzyls, and fatty acids of therapeutic importance (krzaczkowski et al. 2008) . bryophytes are known to possess antibiotic property (banerjee and sen 1979; banerjee 2000; singh et al. 2007; shirzadian et al. 2009; savaroglu et al. 2011) . their antibiosis has been evaluated against a large number of plant and human pathogenic fungus (mekuria et al. 2005) . antimicrobial compounds from bryophyte can cure the problems of conventional antibiotic resistance (vanden bossche et al. 1998) . the antifungal efficacy is tested by disc diffusion assay and microdilution method ( fig. 9 .5). different concentrations of the extracts are prepared and checked for their antifungal efficacy against phytopathogenic fungi. they may be fungicidal or fungistatic in nature, interfering at cellular, genetic level and creating blockage at metabolic pathways. extracts are made on several organic solvents or water extractions and also mixture of one or two organic solvents. the solvents popularly used are ethanol, methanol, chloroform, ether, dimethyl sulfoxide (dmso), acetone, chloroform, and hexane (table 9 .5). sporophytes and gametophytes of different bryophytes at different stages of growth and at a different amount are first surface sterilized and then crushed on the organic solvents and used as antifungals in vitro against the fungal pathogens (wolters 1964 (sabovljevic et al. 2011; pejin et al. 2012; veljic et al. 2009; gahotri and chaturvedi 2011; alam et al. 2011; deora and jain 2008; dey and de 2011; deora and suhalka 2017) . actinobacteria are a group of gram-positive filamentous bacteria that are called as the branched bacteria or ray fungi (from greek actis, ray beam, and mykes, fungus) and are characterized with the high g + c content occurring in mostly aerobic conditions but occasionally being anaerobes (ludwig and klenk 2005; olanrewaju and babalola 2019). their morphology varies from forming branching filaments or mycelial growth to external spores. they are ubiquitous in nature ranging their distribution from soil and human microbiota to plant and even animal kingdom. they are predominant in aquatic as well as terrestrial ecosystem playing a major part in mineralization and recycling of organic matters leading to soil formation (sharma et al. 2014 ). they are not only free-living members of the ecosystem but also a plant symbiont or endophyte, contributing to the plants' survival in extreme conditions and pursuing several bioactivities in vivo and in vitro. actinomycetes produce a diverse range of secondary metabolites, for example, antibiotics, antitumor, insectrepellent, and immunosuppressive agents, and plant growth-promoting regulators (pgprs) that are of immense pharmaceutical and agricultural importance. they are the prime producers of diverse antibiotics after the landmark discovery of penicillin in the year 1928. the single genus of streptomyces sp. itself produces 76% of the total known bioactive (10,000 are produced by actinobacteria out of 23,000 produced by microorganisms, almost 45%) compounds from actinobacterial and riccia gangetica curvularia lunata deora and suhalka (2017) , guhil (2015, 2016) bacterial source (berdy 2012) and is known to be the prime organism in the pharmaceutical world. they are equally profitable when isolated from plant source and designated as endophytic actinomycetes. so exploitation of the actinobacterial novel bioactive compounds both from endophytic and non-endophytic source is the ultimate way to fight against human and plant diseases. here we focus only on actinobacterial compounds' antifungal activity and role in plant protection from deadly diseases caused by severe phytopathogens leading to irreparable crop loss and economic breakdown of agricultural sectors. actinomycetes from soil source are selected based on the enrichment culture technique and are plated on selective media for isolation. antifungal agents, for example, nystatin and cycloheximide, are supplemented for the inhibition of fungal contamination. for isolation of endophytic actinobacteria from plant source, plants are first selected and surface sterilized for the elimination of the epiphytic contaminants and finally plated on the selective growth media like starch casein nitrate agar (scna), chitin-vitamin b, tap water yeast extract agar (twya), soybean, humic acid-vitamin b (hv), yeast extract casamino acid (yeca), modified gausse, and glycine-glycerol (ivantiskaya et al. 1978; küster 1959; küster and williams 1964; williams and davies 1965; hayakawa and nonomura 1987; crawford et al. 1993) . international streptomyces project (isp) medium is also popular media used for isolation, and they are supplemented with amino acids (l-asparagine for isp 5, tryptone for isp 1), inorganic trace salts, starch or carbohydrate sources (malt extract for isp 4), and agar as solidifying agent. ph set at near to optimum or slightly basic is mandatory for proper isolation techniques using isp medium. the actinomycete isolates are grown in solid or liquid medium for their antifungal bioactivity detection. antagonistic activities of the potent isolates are tested by growing them on both sides of the fungal hyphae, and isolate having anti-phytopathogenic activity will inhibit the growth of the pathogens. actinobacterial aqueous-or solvent-based extracts will be evaluated for either fungistatic or fungicidal activity by agar welldiffusion techniques. soluble bioactive compounds of antifungal importance will be extracted using wide range of organic solvents followed by purification by column and thin-layer chromatographic techniques. hplc analysis will be the most useful method for the detection of the purity of the compound, and further nmr studies are needed for the proper identification of the bioactive compound. cell line studies are made with the coupling of bioinformatics tools for the proper knowledge about their mode of action. actinobacteria can be a part of plant as endophyte, rhizospheric soil as symbiont for plant growth-promoting substance producer, and organisms' normal microbial flora as gut microorganism. so they are ubiquitous in their distribution. out of several biologically potent compound produced from the actinobacterial source, antibiotics are the major contribution of these microorganisms toward human civilization. all the known antibiotics (blasticidin, mildiomycin, natamycin, validamycin, kasugamycin) are of actinobacterial (most of them are the streptomyces sp.) source showing protective activity for the plants against agricultural fungal pathogens (tables 9.6 and 9.7). as human are dependent completely on nature and more particularly natural components of agricultural origin and importance, dependence on agricultural crops is of a known fact. but the problem arises when the crops are affected most by the fungal pathogens leading to huge crop loss, and thus the search for novel antibiotics is on, and the search has shifted to actinobacterial source, and endophyte plays an important role in this respect. there are significant reports of antifungal compounds from bacterial origin, but now the focus has shifted to microbes of endophytic origin (table 9 .8). till date, a huge number of antibiotics are already reported and have minimized the crop loss to a notable amount ( fig. 9.6 ). antibiotics and other antifungal compounds include munumbicins a, b, c, d, e-4, and e-5, vanillin, saadamycin, 5,7-dimethoxy-4-p-methoxyphenyl coumarin, coronamycin, and fistupyrone isolated from different strains of streptomyces (shan et al. 2018; costa et al. 2013; igarashi et al. 2002; tian et al. 2004; zin et al. 2007 ) and are protecting a large number of cereals and other important cash crops from being affected by these common contaminants. endophytic actinobacteria directly counteract with fungal plant pathogens not only by producing bioactive compounds but also by enhancing the plant's growth through the production of plant growth promoters and making the plant less susceptible to pathogenic invasion. they are efficient agent of reducing the symptoms that arise due to exposure to environmental stress (shimizu 2011) . enhanced production of indole acetic acid (iaa) was mediated by streptomyces sp. (isolated from centella asiatica) and nocardiopsis sp. (dochhil et al. 2013; shutsrirung et al. 2014; gangwar et al. 2014) . experimental trials on cucumber indicate positive result as the isolates actinoplanes campanulatus, micromonospora chalcea, and streptomyces spiralis enhanced plant growth and improved yield conditions (el-tarabily et al. 2010) . other than auxin, auxin-like similarly functioning molecules named as pteridic acids a and b are found to be inducers of adventitious root proliferation in kidney bean plants at very minute concentrations of 1 mm (igarashi et al. 2002) . chitin is a major fungal cell wall polysaccharide (the second most abundant polysaccharide in nature after cellulose) component and is the first line of defense of fungal cells. actinobacteria antagonize the fungal cell by producing chitinases (an enzyme capable of hydrolyzing fungal cell wall) and break the glycosidic bonds in chitin and lead to the death of the pathogenic cell. endophytic kitasatosporia sp. (isolate of catharanthus roseus) and kibdelosporangium sp. (isolate of achillea fragrantissima) are reported to be chitinase producers (el-shatoury et al. 2009; mini priya 2012) . actinoplanes missouriensis isolated from lupinus sp., a member of fabaceae family, produces chitinase causing hyphal cell lysis and reducing the conidial germination rate and protects the plant from pathogenic attack of plectosporium tabacinum, the causal agent of lupin root rot in egypt (el-tarabily 2003; el-tarabily and sivasithamparam 2006) . siderophores are soluble, small, high-affinity iron carriers produced by bacterial or fungal members and are involved in the transportation of iron (fe 3+ ) across the cell membrane. they have caught sudden attention due to their involvement in plant growth promotion as well as antagonistic ability against phytopathogens (cao et al. 2005; tan et al. 2006; rungin et al. 2012) . endophytic actinobacteria from aloe vera, mentha arvensis, and ocimum sanctum are known to be producers of hydroxymate type and catechol type of siderophores, and the isolate saccharopolyspora o9 is known to be the potent inhibitor howell and stipanovic (1980) , homma et al. (1989) , thomashow et al. (2002) and smith et al. (1993) harpin proteins (erwinia amylovora), trade name: harpin αβ (proact) induction of systemic acquired resistance (sar) and less susceptibility to fungal and bacterial disease wei et al. (1992) strobilurin and oudemansin (members of basidiomycete grows on dead wood) commercial synthetic analogues: azoxystrobin and kresoxim-methyl of alternaria brassicicola, botrytis cinerea, and fusarium oxysporum (gangwar et al. 2014; el-shatoury et al. 2009 ). endophytic isolates of cucumis sativus (cucumber), identified as actinoplanes campanulatus, micromonospora chalcae, and streptomyces spiralis, are reported to control the growth and development of damping off, crown rot, and root rot pathogen pythium aphanidermatum. they are known to promote plant growth and to protect seedlings and mature plants. a novel bioactive compound identified as 6-prenylindole was isolated from endophytic streptomyces sp. showing strong antifungal activity against a broad range of phytopathogens: alternaria brassicicola and fusarium oxysporum (igarashi 2004) . another new prenylated indole derivative from endophytic actinobacterial source inhibited the growth of colletotrichum orbiculare, phytophthora capsici, corynespora cassiicola, and fusarium oxysporum (zhang et al. 2014) . naphthomycins a and k isolated from streptomyces sp. cs have antifungal activity against penicillium avellaneum shen 2003, 2007) . biocontrol ability of fistupyrone has made it a useful tool to minimize the crop loss of brassica due to black leaf spot disease caused by alternaria brassicicola (igarashi 2004) . interest on actinomycetes of endophytic origin as an alternative tool for antifungal agent is increasing day by day (table 9 .9). since the beginning of human civilization, whenever human race has faced any turbulence in its path of existence, they have rushed to their green friends, trees, for the ultimate solution. search for bioactive products of medical importance has been a thirst area from time immemorial. whether it is a concern of human or plant health, trees have given answers in all aspects. in the recent past, phytopathogenic infection has pushed the agricultural productive parameters to a real challenge, and plant extracts in its crude and purified form are applied as biocontrol methods (table 9 .10). the existing synthetic chemicals are facing problem of immediate or delayed drug resistance and also issues of nephrotoxicity (the gold standard; amphotericin b), biomagnification, or quality assurance of the food products and thus are inconsistent in their business (goa and barradell 1995; cuenca-estrella et al. 2000) . so green plant extracts are the novel, safest, and the best effective treatment tool in this arena. plants are mysterious in their chemical nature and in respect to their secondary metabolite production. the faith is consistent on green plants due to the fact that plants protect themselves from fungal or bacterial diseases specially for the taxa that occur in marshy shady or water-logged or stress conditions (gurgel et al. 2005) . so the search is primarily made on the wild native taxa or invasive species that have higher potential of antimicrobial production. the knowledge of ethnobotany comes in this context, and tribal people are imitated for the gathering of crude knowledge. the problem of fungal pathogenesis is mainly faced by plants of economic importance, that is, cash crops. a single event of pathogenic attack can affect seriously the demand and supply ratio; thus the sustainability is lost, and restoring the good health of crops is a basic need of agricultural sectors but in an efficient way not hampering the soil health, ecosystem characters, and human health and also should be budget friendly. the search is strictly focused on plants of ethnomedicinal importance as history indicates the ability of medicinal plant extracts in human and animal mycoses and antifungal ability (mathias-mundy and mccorkle secondary metabolites are plants' best weapon against phytopathogenic invasion. several plant extracts have been assessed for their antifungal activity against a variety of phytopathogens of serious agricultural threats (table 9 .11). the metabolites are divided into terpenoids, saponins, phenolic compounds, flavones, flavonoids, flavonols, alkaloids, and coumarins (table 9 .12). plant extracts are primarily tested for antifungal efficacy and further are purified by solvent extraction and chromatographic procedures leading to discovery of new antifungal agents. terpenoids, also called as isoprenoids (under the chemical subclass of prenyllipids), are known to be the oldest group of widespread molecular compounds produced by plants. scher et al. (2004) reported a variety of six sesquiterpenes of antifungal importance against the causal organisms of bunch rot (botrytis cinerea) on grapes, scab of cucurbits (cladosporium cucumerinum), potato blight (phytophthora infestans), rice blast (pyricularia oryzae), and blotch of wheat (septoria tritici). sesquiterpene isolated from polygonum punctatum (dotted knotweed of knotweed family polygonaceae) named after the chemical polygodial is an effective control agent of zygosaccharomyces bailii (a common food spoilage yeast). scab of cucurbits is a common and devastating fungal pathogenic disease in agricultural fields, and this disease is to some extent prevented by the use of clerodane diterpenes extracted from detarium microcarpum, a plant of leguminosae family (cavin et al. 2006) . skaltsa (2000) reported fungi inhibitory (cunninghamella echinulata) activity of costunolide and eudesmane derivatives isolated from centaurea plants. other than terpenes, saponins (triterpene ad steroidal saponins) are also effective antifungals reported from plant sources. tea is one of the most vital cash crops in terms of foreign money earning and the most popular beverage having antioxidative properties. pathogenic infection by pestalotia longiseta causes a huge loss of tea production. nagata et al. in the year 1985 isolated triterpenoid saponins camelids i and ii from the leaves of camellia japonica (japanese camellia) that inhibited the tea pathogen p. longiseta. cucurbitacins i, a, b, q, and e isolated from cucurbitacins (ecballium elaterium) have antifungal activity against botrytis cinerea (har-nun and meyer 1990) . phenolics are odorous compounds having antifungal compounds and are also responsible for the plant pigment production. phenolics cover a large number of chemical compounds, for example, alkylated phenols, anthraquinones, coumarins, phenolic acid, phenols, phenylpropanoids, quinines, xanthones, hydroxycinnamic acid, p-coumaric acid, ferulic acid, and chlorogenic acid. phenol derivatives like crassinervic acid (p. crassinervium), aduncumene (p. aduncum), hostmaniane (p. hostamannianum), and gaudichaudanic acid (p. gaudichaudianum) are effective against strawberry blossom blight pathogen cladosporium cladosporioides (lago et al. 2004 ). 3-acetyl-4-acetoxyacetophenone showed antifungal activity against spendley et al. (1982) , potterat et al. (1987) , martson et al. (1988) , marston et al. (1993) , viturro et al. (2004) , cavin et al. (2006a) , and dhatwalia et al. (2009) pinocembrin from leaves of populus deltoides (salicaceae) shain and miller (1982) , hoof et al. (2008) cladosporium fruit and leaf rot and bitter root (cladosporium gloeosporioides) long-chain alcohol from peels of young fruit of persea americana from lauraceae, methylripariochromene a from roots of eupatorium riparium (asteraceae) prusky et al. (1983) , ratnayake bandara et al. (1992) pine needle pathogen (dothistroma pini) stearic acid from needles of pinus radiata (pinaceae) franich et al. (1983) pathogen of corn, sorghum, apple (helminthosporium carbonum) luteone and wighteone from leaf surface of lupinus albus (leguminosae) ingham et al. (1983) black and brown spot of banana (colletotrichum musae) dopamine from unripe banana fruit (musa sp.) muirhead and deverall (1984) powdery mildew of grains (erysiphe graminis) gramine from leaves of hordeum vulgare (poaceae) wippich and wink (1985) leaf spot, rots, and blights (alternaria alternata), disease of cereal (penicillium verrucosum) alizarin and emodin from root of rubia tinctorum of rubiaceae, alkylated phenols of peel and pulp of mangifera indica (anacardiaceae) cojocaru et al. (1986) , manojlovic et al. (2005) maize rot (fusarium moniliforme), epidemic outbreak of glume and kernel discoloration (curvularia lunata) flavan-4-ols of root bark of sorghum cultivars of poaceae jambunathan et al. (1986) (continued) kobayashi et al. (1987) , endo et al. (1990) , cho et al. (1998) blue mold of tobacco (peronospora tabacina) diterpenoids from nicotiana tabacum of solanaceae reuveni et al. (1987) leaf and fruit pathogen (cladosporium cladosporioides) canaliculatol from bark of stemonoporus canaliculatus and long-chain alcohol from persea americana, phenylethanone from euodia lunuankenda, sinharine and methylsinharine from glycosmis cyanocarpa, illukumbin from glycosmis mauritiana (rutaceae), phenylethanone from euodia lunuankenda (lauraceae), benzoquinone from croton lacciferus (euphorbiaceae) bokel et al. (1988) , ratnayake bandara and wimalasiri (1988) , kumar et al. (1990) , greger et al. (1992) , pacher et al. (2001) , springob and kutchan (2009) miles et al. (1991) , miles et al. (1993) , lee et al. (2003) , deng and nicholson (2005) and yoganandam et al. (2009) (continued) sclerotinia sp. phenolic structures when contain a carbonyl group are known to be flavones, and the addition of an extra 3-hydroxyl group indicates flavonol. flavonoids are also known to hydroxylated phenolics but occurring as a c6-c3 unit linked to aromatic ring. not only plant samples directly but also plant derivatives like porpolis (galangin isolated from the bee glue or resinous mixture produced as a result of the mixture of tree buds, sap, botanical extracts, and bee exudates) are shown to be antifungal against green rot or mold of tangerine (pathogens penicillium digitatum, p. italicum) and also control postharvest disease of cereal grains, legumes, and tree nuts caused by a. flavus (afolayan and meyer 1997) . flavones (6,7,4′-trihydroxy-3,5′dimethoxyflavone, 5,5′-dihydroxy-8,2′,4′-trimethoxyflavone) from artemisia giraldi are effective against a. flavus infections (cowan 1999) . leaf wax of arrabidaea brachypoda (brazilian medicinal plant from bignoniaceae) contains herger et al. (1988) and abdu-allah and elyousr (2017) cassia tora (dealcoholized extract of leaves) mukherjee et al. (1996) thymol, carvacrol, citronellol, geraniol, citral, perillyl, menthol, eugenol, 1,8cirsiliol, cirsimaritin, and hispidulin and is showed to be effective against cladosporium sphaerospermum (alcerito et al. 2002) . galeotti et al. (2008) against fusarium oxysporum f. sp. dianthi (galeotti et al. 2008) . fusarium culmorum, a serous pathogen of seedling blight, foot rot, ear blight, stalk rot, and common rot of cereals and grasses, is found to be inhibited by six commercial coumarins: bergapten, herniarin, umbelliferone, xanthotoxin, and scopoletin. tithonia diversifolia, the source of tithoniamarin, is effective against the anther smut fungus microbotryum violaceum, earlier known as ustilago violacea (yemele-bouberte et al. 2006) . berberine and jatrorrhizine (alkaloids) are isolated from mahonia aquifolium (a plant of berberidaceae family commonly called as oregon grape and native to western north america) and are effective against human pathogenic candida species. pathogens of mango (c. gloeosporioides), anthracnose of lupin species, postbloom fruit drop of citrus, valencia and navel oranges in florida (caused by c. acutatum), and strawberry (caused by colletotrichum fragariae) are inhibited by findersine, anhydroevoxine, and haplamine (cantrell et al. 2005) . roots of cyathobasis fruticulosa are source of beta-carboline, tryptamine, and phenylethylamine-derived alkaloids and are antifungal in nature (bahceevli et al. 2005 ). essential oils (eos) of aromatic and medicinal plant origin are reported to possess antifungal properties and are of wide spectrum in their application for the control of agricultural pathogen (table 9 .13). eos are mainly categorized under the plants' secondary metabolites and may fall under the category of terpenes, ketones, esters, aromatic phenols, ethers, alcohols, oxides, etc. (fig. 9.7) . they act by inhibiting the fungal hyphal growth either by accumulating in the fungal cell membrane or by crossing the cell membrane and entering into the eukaryotic cell. being lipophilic in their chemical nature, they can easily cross the cell and interrupt in sterol biosynthesis leading to growth retardation and finally cell death. as sterols are the maintenance, compounds of cellular integrity treatment with eo cause fungal cell death. metabolic processes like respiration, replication, transcription, and translation are inhibited. membrane permeability is drastically changed as they cause swelling and disruption of protein-lipid-protein membrane. leakage of useful ions like ca 2+ and k + causes cell death. thymol, carvacrol, eugenol, and related phenolic compounds cause h + and k + leakage and water imbalance and deplete intracellular high-energy molecule (atp). essential oils are extracted from almost every parts of a plant, for example, roots, fruits, barks, twigs, leaves, seeds, and flowers, by several extraction procedures that include hydro and steam distillation, cold pressing, and zataria multiflora lamiaceae fermentation. the antifungal efficacy is checked by direct contact of the essential oil components and fungal hypha and poison food method, following micro or broth dilution techniques, or in vivo fumigation assay is also performed in case of field trials. essential oils from leaves of chenopodium ambrosioides, a member of amaranthaceae family, are effective against storage fungi aspergillus flavus, a. glaucus, a. niger, a. oryzae, colletotrichum gloeosporioides, c. musae, fusarium oxysporum, and fusarium semitectum (jardim et al. 2008) . lemongrass oil from cymbopogon citratus and cymbopogon martini are potent inhibitors of botrytis cinerea, rhizoctonia solani, aspergillus tamari, a. fumigatus, and a. conicus (tzortzakis and economakis 2007; mishra et al. 2015) . the members of lamiaceae family are well known for their pungent odor and are tested for their antifungal activity by agar and broth dilution methods (roby et al. 2013; omidbeygi et al. 2007 ). essential oils extracted from laurus nobilis, syzygium aromaticum, and origanum vulgare are effective antifungal compounds against two pathogens of rice, fusarium culmorum and fusarium verticillioides (rosello et al. 2015) . essential oils from cymbopogon exhibited antifungal activities against rot molds (soundharrajan et al. 2003) . antifungal activities of peppermint and sweet basil were tested against plant pathogenic fungi s. sclerotiorum, rhizopus stolonifer, and mucor sp. (edris and farrag 2003) . antifungal activity of β-dolabrin, γ-thujaplicin, and 4-acetyltropolone was tested against pythium aphanidermatum ifo 32440 (morita et al. 2004) . boyraz and ozcan (2006) tested the antifungal activity of the essential oils isolated from wild turkish summer savory (satureja hortensis). essential oils (carvacrol, thymol, p-cymene) extracted from origanum acutidens are effective against phytopathogens. growth of a. humicola, colletotrichum gloeosporioides, rhizoctonia solani, and phytophthora cactorum was inhibited by the essential oil of asarum heterotropoides var. mandshuricum (dan et al. 2010) . though there are several reports of essential oils being potent anti-phytopathogenic (penicillium purpurogenum, rhizopus stolonifer, spondylocladium austral, penicillium digitatum, penicillium luteum, monilinia laxa, curvularia lunata, etc.) in nature, still there are some problems regarding their maximum use and optimum effectivity. that includes their volatile natures, requirement of close systems, and degradation of eos by oxidation due to presence of extreme amount of hydrogenated compounds (kim et al. 2003 ). we are nourished by mother nature. so it is our prime duty to keep up the normal equilibrium of natural parameters. but in a way to seek solutions, some steps taken toward success may have negative impact on our environment. to fight against the fungal pathogens for the ensuring of better crop productivity, use of chemical fungicide is just another example of that fact. but we must emphasize on products from direct natural origin over the chemically synthesized one. natural products are the best weapon to fight fungal pathogenic diseases on economically important crop species. they are less toxic, stable, and of no side effects when used in crop fields. the crying need of modern era is obtaining pathogen-free crop species in one hand and assurance of environmental sustainability on the other. fungal and bacterial products are already used in large scales followed by the plants' secondary metabolites. phytoalexins as internal molecules are the plants' own defense system. the detailed biochemical analysis of the phytoalexins and study of their regulatory mechanisms are opening up new horizons for universal use of phytoalexin inducing elicitors as plant defense enhancers. mycorrhizae provide the basic line of physical barrier against pathogenic invasion, and reports include their ability to enhance plant growth, thus making the plant nonsusceptible to fungal attack. endophyte on the other hand can enhance the plants' defense system by direct incorporation and open up popular angles of green immunization or plant vaccination. researches on these fields are still scanty, but in the near future, they could lead to the ultimate solution of fungal pathogenic crop loss. effect of certain plant extracts and fungicides against powdery mildew disease of grapevines in upper egypt antimicrobial activity of compounds isolated from algae flavonoid and other constituents of bauhinia manca effects of resveratrol on the ultrastructure of botrytis cinerea conidia and biological significance in plant/pathogen interactions biological activity of resveratrol, a stilbenic compound from grapevines, against botrytis cinerea, the causal agent for gray mold the antimicrobial activity of 3, 5, 7-trihydroxyflavone isolated from the shoots of helichrysum aureonitens extraction and identification of bioactive compounds (eicosane and dibutyl phthalate) produced by streptomyces strain kx852460 for the biological control of rhizoctonia solani ag-3 strain kx852461 to control target spot disease in tobacco leaf 2-9 phytoalexins in defense against pathogens effect of volatile and non-volatile compounds from trichoderma spp. against colletotrichum capsici incitant of anthracnose on bell peppers in vitro antifungal efficacies of aqueous extract of dumortiera hirsuta (swaegr.) nees against sporulation and growth of postharvest phytopathogenic fungi evaluation of streptomyces griseorubens e44g for the biocontrol of fusarium oxysporum f. sp. lycopersici: ultrastructural and cytochemical investigations interactions between a root-knot nematode (meloidogyne exigua) and arbuscular mycorrhizae in coffee plant development (coffea arabica) foliar epicuticular wax of arrabidaea brachypoda: flavonoids and antifungal activity metabolites of helminthosporium monoceras: structures of monocerin and related benzopyrans trans-trans-3, 11-tridecadiene5, 7, 9-triyne-1,2-diol, an antifungal polyacetylene from diseased safflower (carthamus tinctorius) mycofumigation by the volatile organic compound-producing fungus muscodor albus induces bacterial cell death through dna damage mycorrhizal fungi and trichoderma harzianum as biocontrol agents for suppression of rhizoctonia solani damping off disease of tomato effect of volatile metabolites of trichoderma species against seven fungal plant pathogens in vitro production of gliotoxin on natural substrates by trichoderma virens studies on antagonistic effect against plant pathogenic fungi from endophytic fungi isolated from houttuynia cordata thunb. and screening for siderophore and indole-3-acetic acid production effect of mushroom extracts in the induction of phytoalexins and in the control of soy oidium in a greenhouse impact of mycorrhizal colonisation on root architecture, root longevity and the formation of growth regulators isolation and characterization of muscodor albus i-41.3s, a volatile antibiotic producing fungus influence of seed priming on the development of pearl millet downy mildew (sclerospora graminicola) synthesis and incorporation of the first polyketide synthase free intermediate in monocerin biosynthesis laminarin elicits defense responses in grapevine and induces protection against botrytis cinerea and plasmopara viticola streptomyces sanglieri which colonised and enhanced the growth of elaeis guineensis jacq. seedlings was antagonistic to ganoderma boninense in in vitro studies current status of biological control of plant diseases using antagonistic organisms in india status and prospects for enhancing the uptake of antagonistic organisms for nematode management in india alkaloids and aromatics of cyathobasis fruticulosa (bunge) aellen antimicrobial activities of bryophytes a review antibiotic activity of bryophytes an endophytic myrothecium inundatum producing volatile organic compounds muscodor albus strain gba, an endophytic fungus of ginkgo biloba from united states of america, produces volatile antimicrobials increasing the productivity and product quality of vegetable crops using arbuscular mycorrhizal fungi: a review seaweed polysaccharides as bio-elicitors of natural defenses in olive trees against verticillium wilt of olive thoughts and facts about antibiotics: where we are now and where we are heading in vitro screening of bryophytes for antimicrobial activity effect of phosphate and the arbuscular mycorrhizal fungus glomus intraradices on disease severity of root rot of peas (pisum sativum) caused by aphanomyces euteiches canaliculatol, an antifungal resveratrol trimer from stemonoporous canaliculatus induction and identification of sativan and vestitol as two phytoalexins from lotus corniculatus the cytosporones, new octaketide antibiotics isolated from an endophytic fungus phytoalexins induction in rubiaceae the camalexins: new phytoalexins produced in the leaves of camelina sativa (cruciferae) anti-fungal effects of cocoa tannin on the witches' broom pathogen crinipellis pernicious applied and environmental microbiology the chemical composition, antifungal, antioxidant and antimutagenicity properties of bioactive compounds from fungal endophytes associated with thai orchids isolation and identification of antifungal and antialgal alkaloids from haplophyllum sieversii isolation and characterization of endophytic streptomyces antagonists of fusarium wilt pathogen from surface sterilized banana roots isolation and characterization of two phytoalexins from rice as momilactones a and b munumbicins, wide-spectrum antibiotics produced by streptomyces nrrl 30562, endophytic on kennedia nigriscans munumbicins e-4 and e-5: novel broad-spectrum antibiotics from streptomyces nrrl 3052 aspectos bioquímicos e moleculares da resistência induzida bioactive diterpenes from the fruits of detarium microcarpum in vitro evaluation of fungicides, plant extracts and biocontrol agents against brown leaf spot of paddy bioactive diterpenes from the fruits of detarium microcarpum crop diseases and their management. phi learning private limited antifungal activity and action mechanism of ginger oleoresin against pestalotiopsis microspora isolated from chinese olive fruits studies on a chlorogenic acid-producing endophytic fungi isolated from eucommia ulmoides oliver antifungal activity of cinnamaldehyde and eugenol congeners against wood-rot fungi antifungal and antiviral products of marine organisms cytotoxic and antifungal triterpene glycosides from the patagonian sea cucumber hemoiedema spectabilis antimicrobial activity of 4-hydroxybenzoic acid and trans 4-hydroxycinnamic acid isolated and identified from rice hull diversity and antifungal activity of fungal endophytes of asparagus racemosus willd insecticidal secondary metabolic products from the entomogenous fungus fusarium larvarum 12-heptadecenyl)-resorcinol, the major component of the antifungal activity in the peel of mango fruit antifungal activity of neo-clerodane diterpenoids from scutellaria the manual of biocontrol agents effect of water activity on the production of volatile organic compounds by muscodor albus and their effect on three pathogens in stored potato biological and molecular comparison between localized and systemic acquired resistance induced in tobacco by phytophthora megasperma glycoprotein elicitin biological control of phytopathogenic fungi by endophytic actinomycetes isolated from maize (zea mays l) plant products as antimicrobial agents identification of three hydroxyflavan phytoalexins from daffodil bulbs phytoalexins from other plant families isolation and characterization of actinomycete antagonists of a fungal root pathogen susceptibility of fluconazole-resistant clinical isolates of candida spp. to echinocandin ly303366, itraconazole and amphotericin b biochemical defense mechanisms in cotton plants against ramularia leaf spot mediated by silicon in vitro antifungal activity of 2-(3,4-dimethyl-2,5-dihydro-1h-pyrrol-2-yl)-1-methylethyl pentanoate, a dihydro -pyrrole derivative phytoalexin accumulation in tissues of brassica napus inoculated with leptosphaeria maculans naphthalene, an insect repellent, is produced by muscodor vitigenus, a novel endophytic fungus activities of essential oils from asarum heterotropoides var. mandshuricum against five phytopathogens antagonist actinomycetes metabolites against plant pathogens fungi of agricultural importance induction of phytoalexins and proteins related to pathogenesis in plants treated with extracts of cutaneous secretions of southern amazonian bufonidae amphibians natural products in crop protection bioassay-guided isolation of allelochemicals from avena sativa l.: allelopathic potential of flavone c-glycosides antifungal activity of crude extracts from brown and red seaweeds by a supercritical carbon dioxide technique against fruit postharvest fungal diseases rhizospheric streptomycetes as potential biocontrol agents of fusarium and armillaria pine rot and as pgpr for pinus taeda geldanamycin, a new antibiotic induction of fusarium solani mutants insensitive to tomatine, their pathogenicity and aggressiveness to tomato fruits and pea plants molecular engineering of resveratrol in plants antifungal properties of surangin b, a coumarin from mammea longifolia phytochemical analysis and antifungal activity of moss bryum cellulare against some phytopathological fungi studies on antifungal potential of bryum cellulare against spore germination of fungus curvularia lunata in vitro antifungal activity of plagiochasma appendiculatum against alternaria solani evaluation of bryophyte for green fungicides as alternative treatment to control plant pathogen oxidative ring contraction of the phytoalexin cyclobrassinin: a way to brassilexin brassilexin, a novel sulphur-containing phytoalexin from brassica juncea l., (cruciferae) secondary metabolites production by actinomycetes and their antifungal activity antifungal bryophytes: a possible role against human pathogens and in plant protection isolation, characterization and antimicrobial activity at diverse dilution of wheat puroindoline protein free fatty acid accumulation and quality loss of stored soybean seeds invaded by aspergillus ruber molecular communication in interactions between plants and microbial pathogens seed germination enhancing activity of endophytic streptomyces isolated from indigenous ethno-medicinal plant centella asiatica interactions between an arbuscular mycorrhizal fungus (scutellospora heterogama) and the root-knot nematode (meloidogyne incognita) on sweet passion fruit (passiflora alata) application of plant extracts as inducers to challenge leaf rust of wheat inhibitory effect and mechanism of tagetes erecta l. fungicide on fusarium oxysporum f evaluating novel microbe amended composts as biocontrol agents in tomato biological activity summary for cocoa (theobroma cacao l.) effect of salicylic acid and structurally related compounds in the accumulation of phytoalexins in cotyledons of common bean phenylphenalenone phytoalexins, will they be a new type of fungicide? antifungal activity of peppermint and sweet basil essential oils and their major aroma constituents on some plant pathogenic fungi from the vapor phase production and genetic improvement of a novel antimycotic agent, saadamycin, against dermatophytes and other clinical fungi from endophytic streptomyces sp. hedaya48 antimicrobial activities of actinomycetes inhabiting achillea fragrantissima (family: compositae) an endophytic chitinase-producing isolate of actinoplanes missouriensis, with potential for biological control of root rot of lupine caused by plectosporium tabacinum performance of three endophytic actinomycetes in relation to plant growth promotion and biological control of pythium aphanidermatum, a pathogen of cucumber under commercial field production conditions in the united arab emirates nonstreptomycete actinomycetes as biocontrol agents of soil-borne fungal plant pathogens and as plant growth promoters structures of antifungal diarylheptenones, gingerenones a, b, c and isogingerenone b, isolated from the rhizomes of zingiber officinale coronamycins, peptide antibiotics produced by a verticillate streptomyces sp. (msu-2110) endophytic on monstera sp antifungal, anti-oomycete and phytotoxic effects of volatile organic compounds from the endophytic fungus xylaria sp. strain pb3f3 isolated from haematoxylum brasiletto new endophytic isolates of muscodor albus, a volatileantibiotic-producing fungus effect of substrate on the bioactivity of volatile antimicrobials produced by muscodor albus antifungal volatile organic compounds from the endophyte nodulisporium sp. strain gs4d2ii1a: a qualitative change in the intraspecific and interspecific interactions with pythium aphanidermatum preharvest treatments with chitosan and other alternatives to conventional fungicides to control postharvest decay of strawberry fungistatic effects of pinus radiata needle epicuticular fatty and resin acids on dothistroma pini blue-green alga anabaena laxa. i isolation and biological properties plant phenolics, lignification arbuscular mycorrhiza reduces susceptibility of tomato to alternaria solani antifungal metabolites from phomopsis sp. by254, an endophytic fungus in gossypium hirsutum comparative efficacies in vitro of antibacterial, fungicidal, antioxidant, and herbicidal activities of momilactones a and b antifungal and antibacterial potential of methanol and chloroform extracts of marchantia polymorpha l flavonoids from carnation (dianthus caryophyllus) and their antifungal activity interactions between a fluorescent pseudomonad, an arbuscular mycorrhizal fungus and a hypo virulent isolate of rhizoctonia solani affect plant growth and root architecture of tomato plants diversity and biopotential of endophytic actinomycetes from three medicinal plants in india the diversity, plant growth promoting and antimicrobial activities of endophytic actinomycetes isolated from emblica officinalis gaertn agriculture and bioactives: achieving both crop yield and phytochemicals isolation and characterization of endophytic actinomycetes from mangrove plant for antimicrobial activity two phytoalexins from sugar beet (beta vulgaris) leaves lass-florl c (2013) the mediterranean red alga asparagopsis taxiformis has antifungal activity against aspergillus species introduction of some new endophytic bacteria from bacillus and streptomyces genera as successful biocontrol agents against sclerotium rolfsii fluconazole: an update of its pharmacodynamic and pharmacokinetic properties and therapeutic use in major superficial and systemic mycoses in immunocompromised patients plant-fungal interactions: the search for phytoalexins and other antifungal compounds from higher plants sulfur containing cinnamides with antifungal activity from glycosmis cyanocarpa phytoalexin emit indolstruktur aus kohlrabi (brassica oleracea var. gongylodes) cytokinins mediate resistance against pseudomonas syringae in tobacco through increased antimicrobial phytoalexin synthesis independent of salicylic acid signaling metabolic products of fusarium larvarum fuckel. the fusarentins and the absolute configuration of monocerin potential of horsetail (equisetum sp.) preparations in the synthesis of defense metabolites in soy (glycine max l.) cotyledons and the effect on the growth of rhizoctonia solani kuhn, in vitro comparative transcriptomics of rice reveals an ancient pattern of response to microbial colonization chemical composition, antifungal and antitumor properties of ether extracts of scapania verrucosa heeg. and its endophytic fungus chaetomium fusiformis in vitro antifungal activity of dragon's blood from croton urucurana against dermatophytes multiple control levels of root system remodelling in arbuscular mycorrhizal symbiosis antifungal effect of five aqueous plant extracts on mycelial growth of penicillium expansum isolated from rotted yam tubers in storage alterations in root exudation of intercropped tomato mediated by the arbuscular mycorrhizal fungus glomus mosseae and the soil borne pathogen fusarium oxysporum f.sp. lycopersici host-pathogen interactions: xix. the endogenous elicitor, a fragment of a plant cell wall polysaccharide that elicits phytoalexin accumulation in soybeans tit for tat? a mycorrhizal fungus accumulates phosphorus under low plant carbon availability the accumulation of inhibitory compounds in the induced resistance response of carrot root slices to botrytis cinerea cucurbitacins protect cucumber tissue against infection by botrytis cinerea pestacin: a 1,3-dihydro isobenzofuran from pestalotiopsis microspora possessing antioxidant and antimycotic activities the effect of post-infectional potato tuber metabolites and surfactants on zoospores of oomycetes the isolation of xanthoxylin from the bark of phytophthora and hendersonula-infected citrus lemon and its fungitoxic effect analysis on blast fungus-responsive characters of a flavonoid phytoalexin sakuranetin; accumulation in infected rice leaves, antifungal activity and detoxification by fungus the fungal dimension of biodiversity: magnitude, significance, and conservation the magnitude of fungal diversity: the 1±5 million species estimate revisited efficacy of artificial humic acid is a selective nutrient in hv agar used for the isolation of actinomycetes genetic manipulation of isoflavone 7-o-methyltransferase enhances biosynthesis of 4′-o-methylated isoflavonoid phytoalexins and disease resistance in alfalfa die wirkung von auszigen aus dem sachalin-staudenknoterich reynoutria sachalinensis (f. schmidt) nakai gegen plizkrankheiten, insbesondere echte mehltauplize production of antibiotics by pseudomonas cepacia as an agent for biological control of soilborne plant pathogens screening of poplar trees for antibacterial, antifungal and antiviral activity suppression of pythium ultimum induced damping -off of cotton seedlings by pseudomonas fluorescens and its antibiotic, pyoluterin effects of fusarium species on defence mechanisms in sorghum seedlings control of post harvest botrytis fruit rot of strawberry by volatile organic compounds of candida intermedia biodiversity of endophytic fungi associated with 29 traditional chinese medicinal plants novel acidic sesquiterpenoids constitute a dominant class of pathogeninduced phytoalexins in maize antimicrobial activities of some brown macroalgae against some soil borne plant pathogens and in vivo management of solanum melongena root diseases antifungal and antiproliferative activities of endophytic fungi isolated from the leaves of markhamia tomentosa screening of novel bioactive compounds from plant-associated actinomycetes isolation of actinomycetes from live plants and evaluation of anti phytopathogenic activity of their metabolites isolation and identification of endophytic actinomycetes and their antifungal activity phytoalexins from the leguminosae fungitoxic isoflavones from lupinus albus and other lupinus species the polyoxins: pyrimidine nucleoside peptide antibiotics inhibiting fungal cell wall biosynthesis validoxylamines as trehalase inhibitors suppression of damping-off disease in host plants by the rhizoplane bacterium lysobacter sp. strain sb-k88 is linked to plant colonization and antibiosis against soilborne peronosporomycetes antibacterial and antifungal activities of brown alga zonaria tournefortii (jv lamouroux) direct isolation of micromonospora on selective media with gentamicin polyphenol concentrations in grain, leaf and callus tissues of mold-susceptible and mold-resistant sorghum cultivars composition and antifungal activity of the essential oil of the brazilian chenopodium ambrosioides l ulvan, a sulfated polysaccharide from green algae, activates plant immunity through the jasmonic acid signaling pathway modulation of phytoalexin biosynthesis in engineered plants for disease resistance metabolic engineering of yeast and plants for the production of the biologically active hydroxystilbene, resveratrol biosynthesis, metabolism, molecular engineering and biological functions of stilbene phytoalexins in plants deciphering the role of phytoalexins in plant-microorganism interactions and human health phytoalexins produced in the leaves of capsella bursapastoris (shepherd's purse) xanthotoxin: a phytoalexin of pastinaca sativa root mycorrhiza-induced resistance and priming of plant defenses isolation of endophytic actinomycetes from catharanthus roseus (l.) g. don leaves and their antimicrobial activity. iranian effect of verticillium wilt (verticillium dahliae kleb.) and mycorrhiza (glomus mosseae) on root colonization, growth and nutrient uptake in tomato and eggplant seedlings the possible association of phytoalexins with resistant gene expression in flax to melampsora lini antifungal potential in crude extracts of five selected brown seaweeds collected from the western libya coast in vitro antifungal, anti-elastase and anti-keratinase activity of essential oils of cinnamomum-, syzygium-and cymbopogon-species against aspergillus fumigatus and trichophyton rubrum insecticidal activities of aromatic plant extracts and essential oils against sitophilus oryzae and callosobruchus chinensis anthraquinones isolated from cassia tora (leguminosae) seed show an antifungal property against phytopathogenic fungi recent development in the use of blasticidin s, a microbial fungicide, as a useful reagent in molecular biology linear b-1,3 glucans are elicitors of defense responses in tobacco-france induce systemic resistance and promotion of plant growth by bacillus spp antifungal activity of pisiferic acid derivatives against the rice blast fungus functional moiety for the antifungal activity of phytocassane e, a diterpene phytoalexin from rice phytoalexin induction in the sapwood of plants of the maloideae (rosaceae): biphenyls or dibenzofurans structural and functional characterization of gene clusters directing non-ribosomal synthesis of bioactive lipopeptides in bacillus amyloliquefaciens strain fzb42 evaluation of essential oils and their components for broad-spectrum antifungal activity and control of late leaf spot and crown rot diseases in peanut bryophytes, a potent source of drugs for tomorrow's medicine? a plant extract acts both as a resistance inducer and an oomycide against grapevine downy mildew outline of a comparative study of criteria used in characterization of the actinomycetes selection of media for isolation of streptomycetes phytoalexins from the solanaceae muscodor sutura, a novel endophytic fungus with volatile antibiotic activities endophytic fungi isolated from oil-seed crop jatropha curcas produces oil and exhibit antifungal activity identification of antifungal principle in the solvent extract of an endophytic fungus chaetomium globosum from withania somnifera isolation, characterization, and bioactivity of endophytic fungi of tylophora indica an endophytic nodulisporium sp. producing volatile organic compounds having bioactivity and fuel potential two fungicidal phenylethanones from euodia lunu-ankenda root bark antifungal and insect antifeedant 2-phenylethanol esters from the liverwort balantiopsis cancellata from chile efficacy of the biofumigant fungus muscodor albus (ascomycota: xylariales) for control of codling moth (lepidoptera: tortricidae) in simulated storage conditions the potential of the fungus, muscodor albus, as a microbial control agent of potato tuber moth (lepidoptera: gelechiidae) in stored potatoes benzoic acid derivatives from piper species and their fungitoxic activity against cladosporium cladosporioides and c. sphaerospermum the production of resveratrol by vitis vinifera and other members of the vitaceae as a response to infection or injury interactions between pea root-inhabiting fungi examined using signature fatty acids mycosubtilin overproduction by bacillus subtilis bbg100 enhances the organism's antagonistic and biocontrol activities momilactones a and b in rice straw harvested at different growth stages antibacterial activity of oriental medicinal plant extracts toward helicobacter pylori mycofumigation with oxyporus latemarginatus ef069 for control of postharvest apple decay and rhizoctonia root rot on moth orchid screening for endophytic fungi with antitumour and antifungal activities from chinese medicinal plants cryptocin, a potent tetramic acid antimycotic from the endophytic fungus cryptosporiopsis cf. quercina antifungal activity of camptothecin, trifolin, and hyperoside isolated from camptotheca acuminata effect of laminarin on aspergillus flavus growth and aflatoxin production use of the endophytic fungus daldinia cf. concentrica and its volatiles as bio-control agents mycorrhizae and plan health isoquinoline alkaloids from macleaya cordata active against plant microbial pathogens pestalofones a-e, bioactive cyclohexanone derivatives from the plant endophytic fungus pestalotiopsis fici bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, a marine algae derived bromophenol, inhibits the growth of botrytis cinerea and interacts with dna molecules screening of a marine algal extract for antifungal activities a new macrolide antibiotic with antitumor activity produced by streptomyces sp. cs, a commensal microbe of maytenus hookeri a novel ansamycin, naphthomycin k from streptomyces sp new bioactive metabolites produced by colletotrichum sp., an endophytic fungus in artemisia annua overview: a phylogenetic backbone and taxonomic framework for prokaryotic systematics inhibitory activities of some marine algae on aflatoxin accumulation naphthoquinone spiroketal with allelochemical activity from the newly discovered endophytic fungus edenia gomezpompae plant disease control: understanding the roles of toxins and phytoalexins in host-pathogen interaction plant extracts, bau-biofungicide and fungicides in controlling some important diseases of rice cv. brri dhan40 biocontrol potential of cyanobacterial metabolites against damping off disease caused by pythium aphanidermatum in solanaceous vegetables bioprospecting for endophytes from australian flora with mycofumigation potential antifungal activity of rubia tinctorum, rhamnus frangula and caloplaca cerina antimicrobial compounds and resistance: the role of phytoalexins and antianticipins fungicidal and molluscicidal saponins from dolichos kilimandscharicus xanthones from polygala nyikensis ethnoveterinary medicine and development: a review of the literature elicitor activity of phytoalexins in soy and sorghum by extracts and tinctures of medicinal plant species synthesis of phytoalexins in soy and sorghum by extracts and tinctures from three forest species structures of ent-herbertane sesquiterpenoids displaying antifungal properties from the liverwort herberta adunca endophytic fungi associated with monarda citriodora, an aromatic and medicinal plant and their biocontrol potential bioactivity of bryophyte extracts against botrytis cinerea, alternaria solani and phytophthora infestans control of fungal decay of apples and peaches by the biofumigant fungus muscodor albus the algal polysaccharide carrageenans can act as an elicitor of plant defense laboratoires goëmar. parc technopolitain atalante muscodor ghoomensis and muscodor indica: new endophytic species based on morphological features, molecular and volatile organic analysis from northeast india muscodor camphora, a new record from cinnamomum camphora muscodor kashayum sp. nov. -a new volatile antimicrobial producing endophytic fungus muscodor strobelii, a new endophytic species from south india response of subterranean clover to dual inoculation with vesicular-arbuscular mycorrhizal fungi and a plant growth-promoting bacterium modulation oh cyp79 genes and glucosilate profiles in arabidopsis by defense pathways potential agrochemicals from leaves of wedelia biflora 60-trihydroxydihydrochalcone from psidium acutangulum fungi and mycotoxins in grain: implications for stored product research endophytic actinomycetes from indian medicinal plants as antagonists to some phytopathogenic fungi chemically characterized cymbopogon martinii essential oil for shelf life enhancer of herbal raw materials based on antifungal, antiaflatoxigenic, antioxidant activity and favorable safety profile volatile antimicrobials from muscodor crispans, a novel endophytic fungus volatile plant metabolites for postharvest crop protection 4-methoxybrassinin, a sulphur-containing phytoalexin from brassica oleracea brassicanal c and two dioxindoles from cabbage brassicanal a and b, novel sulfur-containing phytoalexins from the chinese cabbage brassica campestris l. ssp pekinensis dehydro-4-methoxycyclobrassinin, a sulfur-containing phytoalexin isolated from turnip brassica campestris l. ssp. rapa calophycin, a fungicidal cyclic decapeptide from the terrestrial blue-green alga calothrix fusca biological activity of β-dolabrin, γ-thujaplicin, and 4-acetyltropolone, hinokitiol-related compounds bacillomycin d: an iturin with antifungal activity against aspergillus flavus chemical composition and fungitoxic properties to phytopathogenic fungi of essential oils of selected aromatic plants growing wild in turkey evaluation of 3, 4-dihydroxybenzaldehyde, dopamine and its oxidation products as inhibitors of colletotrichum musae (berk. and curt.) arx in green banana fruits antifungal activities of the leaf extract of cassia tora linn experimentelle untersuchungen über die phytophthora resistenz der kartoffel camellidins, antifungal saponins isolated from camellia japonica different mechanisms for phytoalexin induction by pathogen and wound signals in medicago truncatula glyceollin, a soybean phytoalexin with medicinal properties an endophytic actinomycete, streptomyces sp. aok-30, isolated from mountain laurel and its antifungal activity antimicrobial activities of vernonia tenoreana streptomyces: implications and interactions in plant growth promotion dihydro isocoumarins produced by xylaria sp. and penicillium sp., endophytic fungi associated with piper aduncum and alibertia macrophylla activation of biochemical defense mechanisms in bean plants for homeopathic preparations inhibition of protein biosynthesis by mildiomycin, an antimildew substance antifungal activity of thyme, summer savory and clove essential oils against aspergillus flavus in liquid medium and tomato paste activity of fungal endophytes against four maize wilt pathogens efficacy of some agricultural wastes in controlling root rot of glycine max l. induced by rhizoctonia solani effect of seed inoculation with bacillus subtilis and streptomyces griseus on the growth of cereals and carrots stress induced carbazole phytoalexins in glycosmis species seasonal variation of antibacterial and antifungal activities of the extracts of marine algae from southern coasts of india griseofulvin from xylaria sp. strain f0010, and endophytic fungus of abies holophylla and its antifungal activity against plant pathogenic fungi arbuscular mycorrhiza: the mother of plant root endosymbiosis potential of the volatile producing fungus nodulisporium sp. cf016 for the control of postharvest diseases of apple isolation, abundance and phylogenetic affiliation of endophytic actinomycetes associated with medicinal plants and screening for their in vitro antimicrobial biosynthetic potential distribution and identification of endophytic streptomyces species from schima wallichii as potential biocontrol agents against fungal plant pathogens mutualism and parasitism: the yin and yang of plant symbioses effects of sulfated polysaccharide and alcoholic extracts from green seaweed ulva fasciata on anthracnose severity and growth of common bean (phaseolus vulgaris l.) biological control in greenhouse systems a new working definition of the term "phytoalexin biotransformation of the brassica phytoalexin brassicanal a by blackleg fungus phytoalexins from brassicas: overcoming plants' defenses phytoalexin accumulation and antifungal compounds from the crucifer wasabi pathogen inactivation of cruciferous phytoalexins: detoxification reactions, enzymes and inhibitors antimicrobial activity of rhodobryum ontariense. hemijska industrija the discovery of enfumafungin, a novel antifungal compound produced by an endophytic hormonema species biological activity and taxonomy of the producing organisms ultrastructural observations of pterostilbene fungitoxicity in dormant conidia of botrytis cinerea pers natural occurrence of mycotoxins in foods and feeds -an update review relation between the chemical structure and biological activity of hydroxystilbenes against botrytis cinerea two new antifungal naphthoxirene derivatives and their glucosides from sesamum angolense welw potential of plant extracts and fungicides for managing fusarium oxysporum f. sp lycopersici further evidence for the involvement of a pre-formed antifungal compound in the latency of colletotrichum gloeosporioides on unripe avocado fruits progress in phytoalexin research during the past 50 years antifungal potential and defense gene induction in maize against rhizoctonia root rot by seed extract of ammi visnaga (l.) lam diterpene alcohols from croton lacciferus an antifungal chromene from eupatorium riparium outbreaks of aflatoxicoses in india removal of duvatrienediols from the surface of tobacco leaves increases their susceptibility to blue mold jasmonate and salicylate as global signals for defense gene expression use of algae in strawberry management antimicrobial activity of essential oils and ethanol natural products from plants and fungi as fungicides 227 extract of phlomis fruticosa l. (lamiaceae) growth activities of the sugar beet pathogens sclerotium rolfsii sacc. rhizoctonia solani kühn. and fusarium verticillioides sacc. under cyanobacterial filtrates stress induction of defense responses in zucchini (cucurbita pepo) by anabaena sp. water extract activity of seaweed and cyanobacteria water extracts against podosphaera xanthii on zucchini antioxidant and antimicrobial activities of essential oil and extracts of fennel (foeniculum vulgare l.) and chamomile elicitation of foliar resistance mechanisms transiently impairs root association with arbuscular mycorrhizal fungi antifungal activity and potential use of essential oils against fusarium culmorum and fusarium verticillioides plant growth enhancing effects by a siderophore producing endophytic streptomycete isolated from a thai jasmine rice plant (oryza sativa l. cv. kdml105) bioactivities of extracts from some axenically farmed and naturally grown bryophytes antimicrobial activity of bryum argenteum screening of antimicrobial and antioxidant secondary metabolites from endophytic fungi isolated from wheat (triticum durum) structure biological activity relationships in triterpenic saponins: the relative activity of protobassic acid and its derivatives against plant pathogenic fungi pantoea agglomerans strain eh318 produces two antibiotics that inhibit erwinia amylovora in vitro effectiveness of phenolic compounds against citrus green mould control of penicillium expansum and patulin accumulation on apples by quercetin and umbelliferone determination of antimicrobial and antiproliferative activities of the aquatic moss fontinalis antipyretica hedw muscodor tigerii sp. nov.-volatile antibiotic producing endophytic fungus from the northeastern himalayas muscodor darjeelingensis, a new endophytic fungus of cinnamomum camphora collected from northeastern himalayas bioactivity guided isolation of antifungal compounds from the liverwort bazzania trilobata biosynthesis, elicitation and roles of monocot terpenoid phytoalexins biologically active secondary metabolites of endophytic pezicula sp pinocembrin: an antifungal compound secreted by leaf glands of eastern cottonwood endophytic actinomycetes from tea plants (camellia sinensis): isolation, abundance, antimicrobial, and plant-growth-promoting activities isolation of 2,4-diacetylphloroglucinol from a fluorescent pseudomonad and investigation of physiological parameters influencing its production plant bio-stimulants: a review on the processing of macroalgae and use of extracts for crop management to reduce abiotic and biotic stresses purification and partial characterization of a b-glucan fragment that elicits phytoalexin accumulation in soybean diversity and antimicrobial activity of culturable endophytic fungi isolated from moso bamboo seeds in: maheshwari dk (ed) bacteria in agrobiology: plant growth responses studies on endophytic actinomycetes (i) streptomyces sp. isolated from rhododendron and its antifungal activity introduction study of antifungal activities of bryophyte extracts anti-apoptotic machinery protects the necrotrophic fungus botrytis cinerea from host-induced apoptotic-like cell death during plant infection diversity of endophytic actinomycetes in mandarin grown in northern thailand, their phytohormone production potential and plant growth promoting activity diversity and antifungal activity of the endophytic fungi associated with the native medicinal cactus opuntia humifusa (cactaceae) from the united states antifungal activity of securinine against some plant pathogenic fungi antimicrobial activity of some indian mosses an endophytic phomopsis sp. possessing bioactivity and fuel potential with its volatile organic compounds existence of muscodor vitigenus, m. equiseti and m. heveae sp. nov. in leaves of the rubber tree (hevea brasiliensis müll. arg.), and their biocontrol potential casbene: an antifungal diterpene produced in cell-free extracts of ricinus communis seedlings sesquiterpene lactones from centaurea thessala and centaurea attica: antifungal activity mechanisms of resistance to plant diseases what is the significance of the arbuscular mycorrhizal colonisation of many economically important crop plants? the role of phosphorous nutrition in interactions of vesicular arbuscular mycorrhizal fungi with soil borne nematodes and fungi suppression of cottony leak of cucumber with bacillus cereus strain uw85 management of mycorrhiza in agriculture, horticulture and forestry endophytic naphthopyrone metabolites are co-inhibitors of xanthine oxidase, sw1116 cell and some microbial growths a record of muscodor albus, an endophyte from myristica fragrans in thailand antifungal activity of some essential oils two novel antifungal alka-2,4-dienals from triticum aestivum plant-derived natural products synthesis, function, and application streptomyces sp. 9p as effective biocontrol against chilli soilborne fungal phytopathogens algal polysaccharides as source 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experimental establishment in the host plant antifungal activities of a steroid from pallavicinia lyellii, a liverwort engineering cottonseed for use in human nutrition by tissue-specific reduction of toxic gossypol muscodor cinnamomi, a new endophytic species from cinnamomum bejolghota evaluation of muscodor suthepensis strain cmu-cib462 as a postharvest biofumigant for tangerine fruit rot caused by penicillium digitatum molecular and morphological evidence support four new species in the genus muscodor from northern thailand biocontrol of rhizoctonia solani ag-2, the causal agent of damping-off by muscodor cinnamomi cmu-cib 461 antitumor activity of 4-arylcoumarins from endophytic streptomyces aureofaciens cmuac130 identification of streptomyces sp. tc022, an endophyte in alpinia galanga, and the isolation of actinomycin d structures of moracins e, f, g and h, new phytoalexins from diseased mulberry isolation of three novel sulphur-containing phytoalexins from the chinese cabbage brassica campestris l. ssp. pekinensis (cruciferae) novel sulfur-containing phytoalexins from the chinese cabbage brassica campestris l. ssp. pekinensis (cruciferae) mechanism of kasugamycin action on polypeptide synthesis isolation of endophytic actinomycetes from different cultivars of tomato and their activities against ralstonia solanacearum in vitro isolation, purification and characterization of trichothecinol-a produced by endophytic fungus trichothecium sp. and its antifungal, anticancer and antimetastatic activities antibacterial activity and induction of phytoalexins in bean plants by homeopathic preparations of essential oil of eucalyptus globulus antibiotic production by soil and rhizosphere microbes in situ study on the communities of endophytic fungi and endophytic actinomycetes from rice and their antipathogenic activities in vitro identification of volatile metabolites from fungal endophytes with biocontrol potential towards fusarium oxysporum f. sp. cubense race 4 influence of arbuscular mycorrhizal mycelial exudates on soil bacterial growth and community structure antifungal activity of lipopeptides from bacillus xt1 cect 8661 against botrytis cinerea hypoxylon sp., an endophyte of persea indica, producing 1,8-cineole and other bioactive volatiles with fuel potential diterpene phytoalexins are biosynthesized in and exuded from the roots of rice seedlings antifungal activity of lemongrass (cymbopogon citratus l.) essential oil against key postharvest pathogens antifungal drug resistance in pathogenic fungi phytotoxic and antimicrobial activity of volatile and semi-volatile organic compounds from the endophyte hypoxylon anthochroum strain blaci isolated from bursera lancifolia (burseraceae) volatile organic compounds from endophytic fungi as innovative postharvest control of fusarium oxysporum in cherry tomato fruits studies on the mode of action of the phytoalexin phaseolin characterization of the early response of arabidopsis to alternaria brassicicola infection using expression profiling antimicrobial activity of methanol extracts of fontinalis antipyretica, hypnum cupressiforme and ctenidium molluscum sea weed polysaccharides and derived oligosaccharides stimulate defense responses and protection against pathogens in plants endophytic actinomycetes from azadirachta indica a. juss.: isolation, diversity, and anti-microbial activity the biocontrol effect of mycorrhization on soil borne fungal pathogens and the autoregulation of the am symbiosis: one mechanism, two effects? biocontrol of the pathogen phytophthora parasitica by arbuscular mycorrhizal fungi is a consequence of effects on infection loci 5-methylcoumaranones from mutisia friesiana and their bioactivity a vesicular arbuscular mycorrhizal fungus (glomus intraradix) induces a defense response in alfalfa roots suppression of an isoflavonoid phytoalexin defense response in mycorrhizal alfalfa roots fungal (−like) biocontrol organisms in tomato disease control controlling crop diseases using induced resistance: challenges for the future antifungal activities of essential oils and their constituents from indigenous cinnamon (cinnamomum osmophloeum) leaves against wood decay fungi antifungal activity screening of soil actinobacteria isolated from inner mongolia isolation and identification of an endophytic fungus of polygonatum cyrtonema and its antifungal metabolites loroglossol: an orchid phytoalexin evaluation of fungicides, bio-agents and plant extracts against pyricularia oryzae temporal synthesis and radiolabelling of the sorghum 3-deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3-dimalonyl glucoside peptide synthetase gene in trichoderma virens use of antibiotics for selective isolation and enumeration of actinomycetes in soil biological properties of alkaloids. influence of quinolizidine alkaloids and gramine on the germination and development of powderly mildew, erysiphe graminis f. sp. hordei die verbreitung antifungaler eigenschaften bei moosen the role of stilbenes in resistance of sitka spruce (picea sitchensis (bong) carr) to entry of fungal pathogens muscodor roseus anam. sp. nov., an endophyte from grevillea pteridifolia muscodor albus anam. sp. nov., an endophyte from cinnamomum zeylanicum chemical constituents from the chinese bryophytes and their reversal of fungal resistance metabolites from mangrove endophytic fungus dothiorella sp tetran or triterpenoids from chisocheton paniculatus effects of pre-and post-harvest application of salicylic acid or methyl jasmonate on inducing disease resistance of sweet cherry fruit in storage endophytic fungi harbored in the root of sophora tonkinensis gapnep: diversity and biocontrol potential against phytopathogens tithoniamarin and tithoniamide: a structurally unique isocoumarin dimer and a new ceramide from tithonia diversifolia evaluation of wedelia biflora (linn) d.c for anthelmintic and antimicrobial activity recent trends in studies on botanical fungicides in agriculture effect of polyacetylenic acids from prunella vulgaris on various plant pathogens potent in vivo antifungal activity against powdery mildews of pregnane glycosides from the roots of cynanchum wilfordii fungitoxic non-glycosidic iridoids from alibertia macrophylla diversity and antifungal activity of endophytic fungi associated with camellia oleifera potential of endophytic fungi isolated from cotton roots for biological control against verticillium wilt disease natural plant products as eco-friendly fungicides for plant diseases control-a review regulation of plant immunity through modulation of phytoalexin synthesis a new prenylated indole derivative from endophytic actinobacteria streptomyces sp. neau-d50 studies on chemical constituents in root tuber of cynanchum auriculatum muscodor fengyangensis sp. nov. from southeast china: morphology, physiology and production of volatile compounds bioactive isocoumarins isolated from the endophytic fungus microdochium bolleyi effects of yeast polysaccharide on growth and flavonoid accumulation in fagopyrum tataricum sprout cultures actinobacteria associated with chinaberry tree are diverse and show antimicrobial activity the diversity and anti-microbial activity of endophytic actinomycetes isolated from medicinal plants in panxi plateau china preharvest l -arginine treatment induced postharvest disease resistance to botrytis cinerea in tomato fruits neoverataline a and b, two antifungal alkaloids with a novel carbon skeleton from veratrum taliense bioactive endophytic streptomycetes from the malay peninsula camalexin accumulation in arabis lyrata metabolites of colletotrichum gloeosporioides, an endophytic fungus in artemisia mongolica key: cord-274101-vm9nh8lc authors: perez espitia, paula judith; de fátima ferreira soares, nilda; dos reis coimbra, jane sélia; de andrade, nélio josé; souza cruz, renato; alves medeiros, eber antonio title: bioactive peptides: synthesis, properties, and applications in the packaging and preservation of food date: 2012-02-29 journal: compr rev food sci food saf doi: 10.1111/j.1541-4337.2011.00179.x sha: doc_id: 274101 cord_uid: vm9nh8lc abstract: bioactive peptides are protein fragments which have a positive impact on the functions and conditions of living beings. peptides have shown several useful properties for human health, including antimicrobial, antifungal, antiviral, and antitumor activities. these compounds are produced by almost all species of life. however, they are produced in limited quantities in nature. as a result, researchers have tried to synthesize bioactive peptides to study their properties and applications in various areas. among their applications in food preservation, peptides have been incorporated into packaging materials. this review begins with a brief description of the methods used for the synthesis, purification, and characterization of peptides. also, the main bioproperties and mechanisms of action of peptides are discussed. finally, some applications of peptides are presented, especially their use in active packaging, their effects on the polymeric matrix, and peptide migration. food safety is a growing concern of great importance worldwide. recently, the estimated costs of diseases caused by foodborne pathogens was about $152 billion in the united states (scharff 2010) , and it is estimated that in the united states alone about 47.8 million illness cases, 128000 hospitalizations and 3000 deaths will be caused by foodborne pathogens in 2011. the consumption of processed foods with chemical preservatives has led to increased consumer concern and the demand for more natural and minimally processed foods. as a result, researchers have shown a growing interest in natural antimicrobial agents such as certain peptides. bioactive peptides are defined as specific protein fragments that have a positive impact on the functioning or conditions of living beings, thereby improving their health (korhonen and pihlanto 2006) . the beneficial effects are attributed to different properties found in peptides such as antimicrobial (reddy and others 2004; rajanbabu and chen 2011) , antioxidant (sarmadi and ismail 2010) , antithrombotic (wang and ng 1999) , anti-hypertensive (erdmann and others 2008) , and immunomodulatory activities (st georgiev 1990; gauthier and others 2006) , among others. ms 20111071 submitted 9/7/2011, accepted 11/29/2011. authors espitia, soares, coimbra, de andrade, and medeiros are with food technology dept., federal univ. of viçosa, av. p. h. rolfs, s/n, campus univ., 36570-000. viçosa, minas gerais, brazil. author cruz is with food technology dept., state univ. of feira de santana, av. transnordestina, s/n, campus univ., 44036-900. feira de santana, bahía, brazil. direct inquiries to author soares (e-mail: nfsoares10@gmail.com) . peptides with antimicrobial properties are used as the first chemical barrier against microbial attack, being synthesized in response to bacterial infections. they are produced by almost all species of life, from microorganisms, plants and animals, to humans (st georgiev 1990; hancock and diamond 2000) . in animals, antimicrobial peptides are produced mainly in those tissues exposed to adverse conditions such as skin, eyes, and lungs, which are more likely to be in contact with microorganisms (zasloff 2002; papo and shai 2003) . more than 700 antimicrobial peptides have been reported, showing significant variations with respect to their sequence, length, and structure (papo and shai 2003) . antimicrobial peptides have found many applications, including those in biomedical devices, food processing equipment, and food preservation. in food preservation, peptides can be incorporated into materials to create antimicrobial packaging (appendini and hotchkiss 2002) . in this way, antimicrobial packaging plays an important role in maintaining the safety and quality of food, since the aim is to prolong food shelf life and to reduce bacterial growth on the product surface (soares and others 2009a) . this type of active packaging interacts with the product and/or the headspace inside to reduce, inhibit, or retard the growth of microorganisms that may be present (soares and others 2009b) . this review highlights the main methods of peptide synthesis and noteworthy peptide bioproperties. also, specific peptide applications in food preservation are reviewed, focusing on their incorporation in polymeric matrices. finally, the effects of peptide incorporation on packaging characteristics as well as their migration into food are discussed. borgia and fields (2000) . copyright (2000) , elsevier. peptides are biomolecules that contain between 1 to several dozen of amino acid residues joined by peptide bonds. the discovery of the different peptide activities has generated enormous interest in this class of compounds and in the methods of isolation, analysis, purification, identification, and quantification. these methods have been systematically studied and improved. however, most sources of natural peptides are poor in these compounds, thus preventing their isolation in sufficient quantities for research. as a result, there was a growing need to synthesize peptides for application in physiological, chemical, physical, pharmacological, biochemical, and clinical studies. total of 3 methods of peptide synthesis have been developed and improved: chemical synthesis, which uses chemical reagents to mediate peptide bond formation (andreu and rivas 2002) , enzymatic synthesis, in which the peptide bond formation is catalyzed by enzymes (bongers and heimer 1994; boeriu and others 2010) , and the dna recombinant technology synthesis, based on the use of cloning and ribosomal techniques from biological systems for peptide formation (sewald and jakubke 2002) . research on this synthesis method was first initiated more than 30 y ago. however, the construction of peptides has recently become more accessible due to advances in process efficiency, including the development and use of fast coupling reagents, as well as the minimization of side reactions (borgia and fields 2000) . the main aspects of chemical synthesis are protection and activation. protection strategies are intended to provide chemical selectivity necessary for the construction of a particular peptide sequence. activation refers to the chemical coupling necessary to ensure quantitative formation of each peptide bond in the sequence (andreu and rivas 2002) . in chemical synthesis, chemical reagents are used to activate the carboxylic acid (rcooh) of the amino acid, which will donate the acyl group (r-co-) to form the peptide bond. the peptide bond presents a nucleophilic attack of the α-amino group by another amino acid (h 2 n-r). in this synthesis, the reactive functional groups that are not directly involved in peptide bond formation receive prior protection (machado and others 2004) . there are 2 types of chemical peptide synthesis, synthesis in solution (classical synthesis) and solid-phase synthesis. chemical synthesis in solution is performed with all reagents and reaction products dissolved in the medium (kent 1988) . in comparison, solid-phase synthesis (sps) is a simple procedure to produce peptides in large quantities on a solid support which remains insoluble in the reaction medium (shigeri and others 2001) . the solid support is a polymeric resin that has a functional group on its surface (linker) that allows it to form stable bonds in the peptide sequence to the reagent used for the de-protection of the n-amino group. peptide synthesis in the solid phase generally consists on the acylation of an amino acid to be linked to an insoluble support (resin) via a linker ( figure 1 ). after that, the protecting group of the n-terminal is removed (the unprotecting step) to allow the next amino acid of the sequence to be attached to the complex "peptide-linker-resin." the unprotecting-coupling cycle is repeated until the desired sequence is complete. finally, the cleavage reagent is used to separate the complex "peptide-linker-resin." this reagent should also remove the protecting groups of side chains that are stable to unprotecting conditions of the n-terminal group (borgia and fields 2000) . peptide chemical synthesis can use 2 protocols, boc (tertbutyloxycarbonyl) and fmoc (9-fluorenylmethyloxycarbonyl), named according to the type of protector of the reactive group of the amino acids (n-terminal) involved in the synthesis. the first protocol employs the tert-butyloxycarbonyl (boc) group for n-amino protection. this protocol is based on gradual differences in their sensitivity to acids. thus, the boc group is typically removed with trifluoroacetic acid (tfa), while the protecting groups of the lateral chains (ester, ether, and urethane derivatives based on benzyl alcohol) are specifically designed to be stable to repeated cycles of boc removal and are removed only with a specific reagent, a relatively stronger acid, usually hydrofluoric acid (borgia and fields 2000) . the second protocol uses a 9-fluorenylmethyloxycarbonyl (fmoc) as the n-amino protecting group. this protocol provides a greater degree of chemoselectivity than the boc protocol, since the fmoc group is removed under basic conditions (piperidine in n, n-methylpyrrolidone or dimethylformamide), without alteration of the acid-sensitive lateral chains (andreu and rivas 2002) . protection groups of lateral chains are compatible with the fmoc protection group; these are mainly ether, ester, and urethane derivatives based on t-butanol. protection groups of lateral chains are removed by the end of the synthesis using tfa (borgia and fields 2000) . in this method, the peptide bond formation is mediated by an enzyme (protease) in free or immobilized form. the enzymatic method is especially useful in the synthesis of very short peptides (2-5 oligomers) and in the condensation of large peptide fragments (so and others 1998) . proteolytic enzymes such as chymotrypsin, papain, pepsin, subtilisin, termolisin, trypsin, among others, have been used in the presence of organic solvents as catalysts for the synthesis of peptide bonds (ogino and others 1999) . the enzymatic synthesis of peptides has several advantages over chemical methods, including good stereoselectivity and regioselectivity. however, it has certain shortcomings, such as peptide synthesis being thermodynamically unfavorable in water, as well as the secondary hydrolysis of synthesized peptide chains, which hinders their use in peptide synthesis with long sequences (so and others 1998) . thus, the main practical obstacle to employment of a protease for peptide bond formation is finding suitable conditions to allow bond formation without mediating secondary hydrolysis of the peptide or peptide fragments used as reagents (bongers and heimer 1994) . the formation of a peptide bond by enzyme catalysis can occur through several mechanisms, including the reverse hydrolysis reaction of amides and transpeptidation (machado and others 2004; boeriu and others 2010) . the mechanism of the reverse hydrolysis reaction is based on the microscopic reversibility principle. this indicates that the peptide bond formation and hydrolysis reaction come from the same intermediate ( figure 2 ). thus, the reaction conditions are manipulated to shift the equilibrium towards peptide bond formation. the transpeptidation mechanism occurs as a result of the break of a peptide bond, with the formation of an active acyl-enzyme intermediate ( figure 3 ). this intermediate is attacked in the presence of a nucleophile (peptide or amino acid blocked in the α-carboxyl group) and consequently causes the formation of a new peptide bond. for both mechanisms, the equilibrium should shift to the synthesis reaction direction, requiring the use of protective groups of α-amino and carboxyl substrates, the addition of organic solvents to the media reaction, excess substrates, and the removal of products from the reaction medium (machado and others 2004) . this synthesis uses modern methods of cloning and gene expression in microorganisms, allowing the production of a recombinant peptide or several peptides simultaneously. bacteria are the expression system generally used, with e. coli being the most widely used host. since antimicrobial peptides present a natural destructive activity against the host and relative sensitivity to proteolytic degradation, peptides are often expressed as fusion proteins to neutralize their innate toxic activity and increase their expression levels (wang and others 2011) . compared with isolation from natural sources and the other synthesis methods, the recombinant approach offers the most costeffective alternative for large-scale peptide production (li 2011) . peptides are increasingly being produced for various purposes, and these may contain closely related impurities resulting from incomplete reactions or from several side reactions. peptides synthesized for therapeutic and clinical research, as well as for biological and structural studies to explore the structure-activity relationships must have 95% purity or greater (ridge and hettiarachchi 1998) . however, there are other applications where low values of purity, between 70% and 95%, are tolerable (table 1) . peptide purification depends on a series of separation techniques. peptides made on a preparative scale (in gram amounts) can be obtained from a separation process, to isolate one or more individual components from a peptide mixture for future research, or on an analytical scale (about 1 mg of peptide) to identify and determine the relative amounts of some or all components in the mixture. studies on an analytical scale are the first steps for improving separation conditions, which are developed prior to the execution of any preparative separation process (sewald and jakubke 2002) . after the synthesis process, peptides are submitted to a separation procedure consisting of centrifugation and washing to remove residues of the reagents used, as well as products of side reactions. subsequently, peptides are cleaved and subjected to filtration, as well as lyophilization (dagan and others 2002) . the most widely used methods used for the purification of peptides are reverse-phase high-performance liquid chromatography (rp-hplc), ion-exchange chromatography, size exclusion chromatography, affinity chromatography, and capillary electrophoresis ( table 2) . the purity of a peptide must be verified by a method different from that used for purification, since the results of homogeneity derived from such a system can lead to misinformation and be misleading (ridge and hettiarachchi 1998) . thus, the characterization should be analyzed by different methods of mass spectrometry. mass spectrometry has different ionization methods, such as electrospray ionization mass spectrometry (esi-ms), fast atom bombardment mass spectrometry (fab-ms) or matrix-assisted laser desorption/ionization mass spectrome-try (maldi-ms) that can be used for peptide characterization ( table 3) . the different mass spectrometry techniques are based on the accurate determination of the molecular mass-charge ratio of the peptide, as well as on a chemical structure determination, with high sensitivity and resolution (sewald and jakubke 2002) . the growing resistance of pathogens against many commonly used antibiotics has led to research of new compounds with the same functions. an interesting approach is the study of molecules of natural origin to replace antibiotics (bechinger and lohner 2006) . several studies in recent decades have shown that peptides have certain bioactive properties (agyei and danquah 2011). short peptides (1-50 amino acids) with cationic and hydrophobic properties are known to be potent defenses of the host organism, providing activity against a wide variety of pathogenic microorganisms such as gram-negative and gram-positive bacteria, fungi, viruses, and parasites (hancock and sahl 2006) . studies have shown remarkable results of peptide antitumor activity, observed mainly in cancer therapy (korhonen and pihlanto 2006) . although several peptides have biological activity, antimicrobial activity is one of the most studied. one of the most-used analytical techniques to determine peptide antimicrobial activity is the broth microdilution test. in this test, the microorganisms are cultured in titration microplates and the peptide to be tested is added to each well at different concentrations. the microorganism growth causes turbidity in the wells. however, when a certain concentration of the peptide tested inhibits bacterial growth no turbidity is observed. turbidity is usually read by spectrophotometry, with the greatest frequency at 600 nm, but it can also be seen through visual inspection of the wells (otvos and cudic 2007) . the standard methods developed by the clinical and laboratory standards inst. (clsi) have been used to test the activity of antimicrobial peptides. among them are the standards for antimicrobial disk susceptibility tests (clsi 2003) , the method for dilution antimicrobial susceptibility tests for bacteria that grow aerobically m7-a6 (clsi 2006) , and the method for broth dilution antifungal susceptibility testing of yeast m27-a2 (clsi 2002) , all of which have been widely used (jang and others 2006; rubinchik and others 2009; hwang and others 2010) . the most studied peptides are those with antimicrobial activity, characterized by their interaction with the cytoplasmic membrane of the microorganism regardless of the final target (powers and hancock 2003) . factors influencing the antibacterial activity are the electrostatic interactions between the peptide and positively charged and anionic lipids on the surface of the target microorganism. also, the hydrophobicity of the peptide (factor required for insertion into the membrane) and peptide flexibility allow peptide interaction with the microbial membrane (jenssen and others 2006) . although these characteristics are variable according to each peptide, all of them are essential to the function of peptides as antimicrobials. the exact mechanism of action of antibacterial peptides is not yet fully understood. however, there is a consensus among researchers regarding the first step in the initial interaction between peptide and the target cell (reddy and others 2004) . exclusion liquid chromatography based on separation process according to the size of the peptide relative to pore sizes in the stationary phase. used primarily in the early stages of purification of the peptide, when performed in multiple steps used to separate low-molecular-weight impurities from a mixture of peptides. however, the separation of the peptide of interest with other closely related peptides is virtually impossible affinity chromatography based on the biological specificity of the peptide. consists of a ligand (small specific biomolecule such as an antibody) that is immobilized in the column. the separation occurs because of highly specific biochemical interactions between the peptide and the ligand used when a high degree of specificity is required, for example, isolation of a target protein present in low concentration in a biological fluid or a cell extract capillary electrophoresis based on the migration of the peptide according to its charge in solution, depending on the application of an electric field. complementary technique to reversed-phase chromatography used for peptides and proteins table 3 -ionization methods used in mass spectrometry. fundamental principle the ions are produced from a peptide contained in a solvent (for example, an organic compound such as methanol or acetonitrile) that is scattered in a fine aerosol fab-ms the peptide analyzed is mixed with a matrix, which is a non volatile reagent of protection (glycerol, diethanolamine, and triethanolamine, among others), and is bombarded with a beam of high-energy atoms (4000 to 10000 ev) in a vacuum. atoms are of an inert gas such as argon or xenon maldi-ms the peptide analyzed is bombarded by a laser beam (nitrogen), while a matrix (sinapinic acid) is used to protect the peptide. the matrix allows avoiding direct contact of the peptide with the beam, facilitating its vaporization, and ionization the initial attraction between the peptide and the target cell occurs via electrostatic binding between the cationic peptide and the components of the negatively-charged outer cell membrane, such as lipopolysaccharides in gram-negative bacteria or lipoteichoic acid on the surface of gram-positive bacteria (jenssen and others 2006) . this electrostatic interaction removes the native divalent cations (mg 2+ , ca 2+ ) from the cell surface, thus destabilizing the outer membrane and facilitating the entry of the peptide and subsequent peptide contact with the cytoplasmic membrane, a process known as autopromoted uptake (powers and hancock 2003) . after the peptide is bound to the target cell, an arrangement of the peptide occurs on the surface of the cytoplasmic membrane. this fact is of considerable debate, since several arrangement models have been proposed, such as the barrel-stave or the carpet model among others. depending on the model, the peptide can permeabilize the cytoplasmic membrane and/or translocate through it. thus, antimicrobial peptides can be classified into 2 major groups, the first consisting of those peptides which act on the cytoplasmic membrane, and the second consisting of those which have no action on the cytoplasmic membrane of the target microorganism. this means that the peptide just moves into the cell without causing major disturbances in the membrane (powers and hancock 2003; jenssen and others 2006) . peptides acting on the bacterial membrane. several models have been proposed to explain how, after initial attachment, antibacterial peptides are distributed on the surface of the bacterial cytoplasmic membrane to form pores. pore formation results in membrane permeabilization, thereby affecting cellular respiration. it also deprives the microorganisms of their source of energy by interrupting the electrochemical gradient and causing an increase in the flow of water and ions across the membrane, thus leading to cell swelling followed by cellular lysis (bechinger and lohner 2006) . to explain the formation of pores, the aggregate toroidal pore, barrel-stave, and the carpet models have been proposed. the last 2 models, the barrel-stave and carpet model, have been the most widely studied. barrel-stave model. this model describes the formation of a transmembrane channel (pore) through the binding of amphipathic α-helices. the hydrophobic surface of the peptide interacts with the lipid core of the membrane, while the hydrophilic surface of the peptide is oriented inside, producing an aqueous pore (figure 4) . the progressive recruitment of additional peptides to the membrane surface increases the size of the pores, causing the loss of cell content and thus cell death (reddy and others 2004) . this model has been proposed to explain the activity of antimicrobial peptides, such as magainins (matsuzaki and others 1998) . carpet model. in this model, the peptide in high concentration is in contact with phospholipids located on the outer surface of the bacterial membrane, a fact that allows the peptide to permeate the membrane ( figure 5 ). the peptides bind to the surface of the target membrane and cover it like a carpet. according to this model, the peptides exhibit a preferential binding for the phospholipid groups. the binding step is followed by the alignment of the peptide on the membrane surface so the hydrophilic surface is in contact with phospholipid or water molecules, causing a reorientation of hydrophilic residues and creating a hydrophobic core. finally, the peptide disintegrates the membrane by deformation of the membrane curvature (reddy and others 2004) . this model has been proposed to explain the action mechanism of dermaseptins (dagan and others 2002) . toroidal pore model. this model is considered a variant of the barrel-stave model. it is suggested that a perpendicular inclusion of the peptides to the membrane with their hydrophilic regions is associated with phospholipids, whereas their hydrophobic regions are associated with the lipid core. in this process, the membrane is bent inward so the pores are formed (jenssen and others 2006) . the main difference between this model and the barrel-stave model is the intercalation of the peptide with phospholipids to form the pore ( figure 6 ). this model has been used to explain the mechanism of action of the peptide melittin (yang and others 2001) . aggregate model. this model, proposed by wu and others (1999) , has some similarity to the toroidal pore model. this model consists mainly of the arrangement of the peptide in the membrane forming an extension and developing micelle-like aggregate of peptides and lipids, but without adopting a particular orientation (jenssen and others 2006) . peptides with no activity on the bacterial membrane. these antimicrobial peptides have the ability to translocate into bacterial cells without causing membrane permeabilization. the peptide is accumulated within the cell where it reaches a variety of essential cellular processes that result in bacterial cell death (jenssen and others 2006) . the target process includes inhibitions of nucleic acid synthesis, protein synthesis, enzyme activity, and cell wall synthesis. peptides such as buforin ii and pleurocidin have shown this mechanism of action (park and others 1998; patrzykat and others 2002) . there is a growing need for new antifungal agents due to the increased resistance of molds to therapies with regularly used compounds (de lucca and walsh 1999) . peptides have emerged as alternative antifungal agents. initially, the antifungal mechanism of action was described as a result of fungal cell lysis or as a result of interferences in fungal cell wall synthesis. however, the discovery of new antifungal peptides in the last decade has led to the identification of new mechanisms of action, including membrane permeabilization, binding to ergosterol/cholesterol in the fungal membrane, the attack of mitochondria or other intracellular organelles, and the deformation of cell membrane structure (jenssen and others 2006) . according to de lucca and walsh (1999) , fungal peptides can be classified with respect to their mode of action into 3 groups: peptides that act through cellular lysis; peptides that cross the fungal membrane and interact with the intracellular target; and peptides that act by forming pores. peptides acting by cellular lysis. these peptides are characterized by their amphipathic nature, being molecules with 2 faces, one positively charged and the other neutral and hydrophobic. some of these peptides bind only to the membrane surface, damaging the membrane structure, and they may or may not pass through it. peptide smap-29 (a synthetic peptide derived from the sequence of cathelicidins) has shown antimicrobial activity against the fungus trichosporon beigelii by interaction, penetration, and subsequent damage to the cell membrane (lee and others 2002) . this result suggests that the main target of smap-29 peptide is the fungal plasmatic membrane. a similar mechanism was observed for the synthetic peptide ib-amps (an analogue sequence to peptides isolated from seeds of impatiens balsamina), showing antifungal activity by bonding the peptide to the fungal cell membrane and subsequent penetration (thevissen and others 2005) . peptides that pass into the membrane and interact with intracellular targets. these peptides interfere with cell wall synthesis or the synthesis of essential cellular components such as chitin or glucan. as such, the synthetic peptide omiganan (an indolicin analogue peptide, isolated from bovine neutrophils) has shown antifungal activity against candida albicans, and the main mechanism of action of this peptide is related to its activity in the cytoplasmic membrane, resulting in macromolecules synthesis inhibition of macromolecules and finally cell death (rubinchik and others 2009) . pore-forming peptides. these peptides are aggregated in a selective way to form pores of varying sizes, which then allow the passage of ions and other solutes. the synthetic peptide di-k19hc (a halocidin analogue peptide, isolated from the invertebrate marine animal halocynthia aurantium known as sea peach), has shown antifungal activity against several strains of aspergillus and candida (jang and others 2006) . the activity of di-k19hc results in the formation of pores on the surface of fungal membranes. moreover, these researchers pointed out the specific binding of di-k19hc with b-1,3-glucan, a component of the cell wall of fungi. this mechanism has also been observed with the antifungal peptide psacotheasin, isolated from the yellow-spotted long-horned beetle (psacothea hilaris), which has shown activity against c. albicans (hwang and others 2010) . the researchers indicated that there was damage to the cell wall, membrane depolarization with the formation of pores (2.3-3.3 nm), as well as an increase in membrane permeability, all being responsible for the antifungal activity of this peptide. several studies have shown the ability of cationic peptides to inhibit viral infections. the peptide cecropin a has shown antiviral activity against junin virus (jv-which causes argentine hemorrhagic fever). the peptide melittin inhibited jv and herpes simplex virus 1 (hsv-1) multiplication, as well as magainin i and ii, and has shown inhibitory activity against hsv-1 and hsv-2 (albiol-matanic and castilla 2004). antimicrobial peptides isolated from fish, such as tilapia hepcidin 1-5, have shown activity against the nervous necrosis virus (nn virus), an infectious agent that causes mass mortality of several species of marine fish in the larval stage (chia and others 2010) . in addition, synthetic peptides consisting of arginine and tryptophan repetitions have shown activity against vaccinia virus (the cause of cowpox) (mohan and others 2010). the antiviral activity of peptides is often related to virus adsorption and its entry into the host cell or, in other cases, is the result of a direct effect on the viral envelope. thus, the antiviral activity of peptides may result from multiple mechanisms of action, the most important being blocking virus entry through interaction with the host cell and blocking viral entry through interaction with the virus. blocking viral entry through interaction with the host cell. peptides can interact directly with specific viral receptors on the host cell, thus preventing the virus from binding to the cell membrane or binding intracellularly (jenssen and others 2006) . proteoglycans are proteins found in all types of tissue, in intracellular granule secretions as well as in the extracellular matrix and cell surface. proteoglycans are covalently linked to one or more chains of glycosaminoglycans (gag), long polysaccharide unbranched structures, which have a sugar that contains nitrogen and are usually sulfated. gag chains are present on the surface of mammalian cells and their degree of sulfation makes these compounds more anionic. this network of strong negative charges allows gag to attract and bind to small cations, such as enzymes and proteins, and also pathogens such as viruses (spillmann 2001) . heparan sulfate, one type of gag chain, is one of the most important molecules related to viral binding (spillmann 2001) . thus, by blocking heparan sulfate molecules can be inhibited viral infection. jenssen and others (2006) have suggested that antimicrobial peptides which interact with heparan sulfate have the ability to block a number of viral infections. due to the large number of amino acid residues positively charged peptides can interact electrostatically with negatively charged heparan sulfate molecules on the cell surface. studies on lactoferrin (lf) have shown that this peptide prevents infection of the host cell rather than inhibiting virus replication after infection of the target cell. the interaction of lf with heparan c 2012 institute of food technologists ® vol. 11, 2012 r comprehensive reviews in food science and food safety 193 sulfate molecules has been proposed as the mechanism responsible for lf antiviral activity (van der strate and others 2001). similarly, jenssen and others (2006) showed the antiviral activity of synthetic peptides (consisting of arginine and lysine residues) against herpes simplex virus 1 and 2 (hsv-1 and hsv-2). the peptides presented higher affinity in binding to heparan sulfate with an increasing number of cationic residues, thereby blocking the entry of hsv (-1 or -2). in addition, luganini and others (2010) reported the inhibition of cytomegalovirus by binding synthetic peptide dendrimers with molecules of heparan sulfate on the surface of fibroblasts and endothelial cells. thus, cytomegalovirus infection was blocked by the interaction of synthetic peptide binding sites with heparan sulfate. blocking viral entry through interaction with the virus. the interactions of peptides with the glycoproteins (gp) in the viral envelope have been proposed as another mechanism that influences the process of viral entry and virus inactivation. in this way, peptides generated from chemical modification of milk proteins, such as α-lactalbumin, β-lactoglobulin, and lysozyme with 3-hydroxyphthalic anhydride (3-hp) inhibited infection of vero cells with hsv-1 (oevermann and others 2003) . according to those researchers, the antiviral activity of these peptides is based on their direct interaction with viral glycoproteins (gb, gc, gd), which are responsible for adsorption and penetration of the virus into the host cell. similarly, lf has shown the ability to bind to the gp120 glycoprotein (a protein present in the outermost layer of the hiv virus) with antiviral effects, since the gp120 glycoprotein plays an important role in the adsorption and entry of hiv into target cells (van der strate and others 2001; pan and others 2006) . on the other hand, other peptides, such as magainins, have shown antiviral effects through direct interaction with virus cells. egal and others (1999) have indicated that the effect of magainins is the result of the peptide acting on the viral envelope. a similar mechanism was suggested for the activity of mucroporin-m1, a defense cationic peptide present in scorpion venom, which has shown activity against the measles virus, the coronavirus that causes severe accurate respiratory syndrome (sars), and flu virus h5n1 (better known as the bird flu virus) (li and others 2011) . the researchers have suggested that the antiviral activity of the peptide is the result of direct interaction with the virus envelope, thereby reducing viral activity in the host cell. cancer, also known as malignant neoplasm, is a general term that refers to more than 100 different diseases affecting various tissues and different types of cells. all forms of cancer are characterized by abnormal cell growth, that is, they lack the mechanisms that control normal cell division. this lack of regulatory mechanisms is the result of a multistep process involving genetic mutations induced by inheritance or environmental changes (hütter and sinha 2001) . despite major advances in cancer therapy, there is considerable interest in the development of antitumor agents with a novel mode of action, since the cells have shown carcinogenic development of resistance to current chemotherapy (hoskin and ramamoorthy 2008) . carcinogenic cells often become resistant to chemotherapy. this mainly occurs as a result of increased expression of intracellular enzymes for the detoxification of antitumor agents, the correction of dna damage, generation of intracellular organelles with the ability to eliminate and/or transport the drugs out of the tumor, and irreversible defects in the cellular machinery that mediates apoptosis (hütter and sinha 2001) . thus, recent studies have shown peptides as an alternative to conventional cancer treatments. however, not all peptides have selective activity against carcinogenic cells. according to hoskin and ramamoorthy (2008) peptides that have antitumor activity can be classified into 2 major groups: peptides with selective activity, and peptides with non selective activity, that is, those that have activity against bacteria, carcinogenic cells, and healthy cells. peptides with selective activity toward carcinogenic cells. these peptides have activity against bacteria and carcinogenic cells, but not against normal cells. several peptides, such as the cecropins, buforins, and magainins have shown antitumor activity without affecting normal eukaryotic cells (cruciani and others 1991; cho and others 2009) . studies with magainin ii have shown to inhibit the proliferation of carcinogenic cells (in bladder cancer) without any effect on normal cells (lehmann and others 2006) . similar results were observed by chen and others (2009) in the study of the synthetic peptide th2-3 (isolated from tilapia and analogous to the peptide hepcidin), with antitumor activity shown primarily by direct interaction and lysis of target carcinogenic cells (human fibrosarcoma cells). these researchers indicated that the lytic activity of the peptide and proliferative cells were restricted mainly to carcinogenic cells, since normal cells showed no significant effects. likewise, the synthetic peptide th1-5 (isolated from tilapia and an analogue to the peptide hepcidin) has shown antitumor activity against carcinogenic cells, due to interaction with and penetration of the membrane. this peptide has less toxicity toward normal cells supposedly because it can discriminate between healthy cells and carcinogenic ones (chang and others 2011) . researchers have also indicated that the interaction with the cell membrane and its subsequent damage is caused by the formation of pores on its surface. it has been suggested that the internalization of the peptide and the subsequent damage to the mitochondrial membrane activates apoptotic pathways (chang and others 2011) . according to hoskin and ramamoorthy (2008) there are fundamental differences between the membranes of malignant cells and normal cells which allow the selectivity of certain peptides to attack carcinogenic cells without affecting healthy cells. electrostatic interactions between cationic peptides and anionic components of the cell membrane have also been considered an important factor. carcinogenic cells typically have a negative charge due to a higher expression than normal of anionic molecules such as phosphatidylserine (ps) and mucin (glycoprotein) (oren and shai 1997) . however, normal cells are not affected, since these cells have a neutral surface charge, conferred by the zwitterionic nature of most membrane components such as phosphatidylethanolamine (also known as cephalin), phosphatidylcholine, and sphingomyelin (sok and others 1999) . membrane fluidity and the surface area of the cell are also considered factors that contribute to the selectivity of peptides for carcinogenic cells. the fluidity of carcinogenic cells is greater than that of normal cells, which may increase the activity of lytic peptides through the easy destabilization of the membrane. in addition, the carcinogenic cells have a higher surface area than healthy cells due to the presence of greater numbers of microvilli, which are small projections of the cell membrane, irregular in size and shape. the microvilli may allow the bonding between peptide and carcinogenic cells (hoskin and ramamoorthy 2008) . peptides with nonselective activity. this group is comprised of peptides with activity against bacteria, carcinogenic cells, and against normal eukaryotic cells (hoskin and ramamoorthy 2008) . according to papo and shai (2003) non selective activity of these antimicrobial peptides results from their ability to interact with and cause damage to negatively charged membranes and those of a zwitterionic nature. dathe and others (1997) have indicated that the hydrophobic moment of antimicrobial peptides exerts a substantial influence on the neutral lipidic membranes, although it has a small role in the permeabilization of highly charged lipid membranes. peptides of this group include melittin, isolated from bee venom; taquiplesin ii, isolated from the horseshoe crab; defensins, isolated from insects; and plantaricin, a bacteriocin isolated from lactobacillus plantarum (schweizer 2009 ). plantaricin has shown activity against carcinogenic cells and against normal lymphocytes and neuronal cells (sand and others 2010) . the mechanism of action of antitumor peptides consists of permeabilization of the cell membrane mediated by electrostatic interaction. the electrostatic interaction is generated by the negatively charged phospholipids in the cell membrane and the positively charged peptide (schweizer 2009 ). unlike carcinogenic cells, eukaryotic cells have most of their negatively charged phospholipids, particularly ps, in the inner membrane, while neutral lipids are positioned on the outside (zhao and others 2006) . however, the result obtained by sand and others (2010) suggests that in addition to the mechanism of action related to the electrostatic interaction, there is another mechanism which explains the sensitivity of normal eukaryotic cells to plactaricin. probably another negatively charged macromolecule present on the membrane surface of healthy cells is also involved in plantaricin activity. similar results were observed by nan and others (2010) in the study of synthetic peptides consisting of lysine or arginine enriched with tryptophan. the peptide with arginine residues showed higher toxicity against human erythrocytes and mammalian cells. the hydrophobicity of the peptides has been suggested as an important factor in the increase of hemolytic activity and cytotoxicity in mammalian cells, as hydrophobic regions are required for direct interaction between peptide with membrane lipid components. the peptide with arginine residues was slightly more hydrophobic than the peptide with lysine residues. thus, these researchers suggested that small differences in hydrophobicity of these peptides may be responsible for the cytotoxic activity of this peptide in mammalian cells. the growing problem of microorganism resistance to conventional antibiotics, as well as the need for new agents with antibiotic properties has stimulated interest in developing antimicrobial peptides aiming for their application in the medical field (zasloff 2002) . most of the studies are devoted to the development of topical agents with antibacterial and antifungal activities. also, due to their antiviral activity, antimicrobial peptides have also been proposed as chemical preservatives. in the food industry, antimicrobial peptides, especially those produced by bacteria, have been widely researched in recent years due to their potential use as natural preservatives (papagianni 2003; coma 2008; settanni and corsetti 2008) . the direct application of antimicrobial peptides in food preservation can be achieved by 2 methods: the direct addition of peptide to the food matrix, or the inoculation of the food matrix with the bacteriocin producer strain under the conditions favorable for the in situ production of the antimicrobial peptide. bacteriocins can be obtained ex situ by the cultivation of the producer strain at an industrial scale in a food-grade substrate, followed by a series of separation and purification techniques. these ex situ bacteriocins are commercially available in concentrated form, such as alta tm 2341 or microgard tm , and can be added directly to the food matrix. the production of bacteriocins in the food matrix offers several legal and cost advantages. the use of bacteriocin producer strain requires careful selection depending on the particular food intended for inoculation to ensure the producer strains will produce bacteriocins in the necessary amounts to inhibit the target microorganism. in addition to the peptides being studied as antimicrobial agents for direct addition to foods, they also have shown potential for being incorporated into food preparation surfaces (such as cutting surfaces) and processing equipment, as well as in food packaging (appendini and hotchkiss 2002) . active packaging includes the incorporation of antimicrobial agents in the packaging material to control and extend the shelflife of food (soares and others 2009a). these types of packaging are considered an innovative technology in food preservation, since they allow better antimicrobial efficiency on food surfaces, thus improving stability. the development of active packaging by incorporating antimicrobial peptides in food packaging material can be done either to prolong the life of the product or to reduce the microbial load of the packing before use (steven and hotchkiss 2008) . the development of active packaging with antimicrobial peptides can be accomplished by 3 main methods of incorporation: direct peptide incorporation in the polymer; peptide coating on the polymeric surface; and peptide immobilization in the polymer. numerous studies have reported the incorporation of antimicrobial peptides directly in the polymeric material, especially bacteriocins. the peptides are relatively resistant to heat (appendini and hotchkiss 2001) . however, their antimicrobial activity may be greater when heat is not used in the incorporation process. moreover, bioactive peptides incorporated in polymer films must be able to diffuse to the package surface over time to be effective. thus, polymers such as cellulose acetate, alginate, chitosan, and soy protein, among others, have been widely used to develop films with direct incorporation of these antimicrobials (marcos and others 2008; pires and others 2008; sivarooban and others 2008; santiago-silva and others 2009). researchers have studied the antimicrobial activity of bacteriocins incorporated into polymeric materials in synergy with other antimicrobial agents. synergistic activity against staphylococcus aureus, listeria monocytogenes, and bacillus cereus has been observed for nisin with potassium sorbate and garlic oil when incorporated into chitosan films (pranoto and others 2005) . in addition, soy protein films incorporated with nisin, grape seed extract, and ethylenediaminetetraacetic acid (edta) have shown inhibitory synergistic activity against pathogenic microorganisms such as l. monocytogenes, e. coli o157: h7, and salmonella typhimurium (sivarooban and others 2008) . the activity of bacteriocins incorporated into polymeric materials in synergy with other conservation technologies has also been reported. films incorporated with enterocins a and b (bacteriocins produced by enterococcus faecium) have shown synergistic activity when used together with high-pressure processing. thus, the use of antimicrobial packaging developed in conjunction with the high-pressure process allowed the control of l. monocytogenes at below detectable levels after 90 d of storage at 6 • c (marcos and others 2008) . this is an alternative method when the polymer requires extreme processing conditions during packaging material manufacture, such as high pressure and temperature, which can result in inactivation of the antimicrobial agent (appendini and hotchkiss 2002) . in some cases, the antimicrobial coating is done by contacting the film with or immersing it in the peptide solution. in this way, linear low-density polyethylene (lldpe) has been coated with lactocin 705 and lactocin al705 (both bacteriocins produced by lactobacillus curvatus crl705), by direct contact of the film with a bacteriocin solution, showing antimicrobial activity in vitro against lactobacillus plantarum crl691 and listeria innocua 7 (massani and others 2008) . similarly, scannell and others (2000) used alternatively lacticin 3147 and nisin adsorbed on the surface of plastic bags (polyethylene/polyamide) through direct contact of the polymeric material with bacteriocin solution. the film coated with nisin showed inhibitory activity against l. innocua and s. aureus, maintaining its activity for 3 mo either at room temperature or under refrigeration. however, the film coated with lacticin 3147 did not show antimicrobial activity. the researchers suggested that lacticin 3147 was not retained by the polymer (scannell and others 2000) . proper handling of solvents and polymeric structures has been suggested to increase the adsorption of the peptide into the polymer matrix (appendini and hotchkiss 2002) . for example, the polymeric surface can be coated by applying a filmogenic solution that can be deposited on the film surface by the casting method. accordingly, chollet and others (2009) developed a laminated film of polyethylene (pe) and polyamide (pa), with the structure pe/pa/pe, coated with a filmogenic solution of hydroxypropyl methyl cellulose (hpmc) and adsorbed with nisin. the developed film presented antimicrobial activity in vitro against kocuria rhizophila (chollet and others 2009) . peptides can be immobilized or attached to solid supports by physical methods, such as layer-by-layer assembly, or by chemical methods, such as covalent bonding (onaizi and leong 2011) . layer-by-layer assembly. in this process, the peptide is sandwiched between 2 polyionic polymers and the number of peptides and polymers is flexible (figure 7) . the effectiveness of the peptide depends on its relative mobility. the advantage of this method is that it allows the slow release of the peptide embedded in the surface of the polymer. however, a key drawback of this method is that the peptide immobilized in the layers closest to the solid support will not be in direct contact with the target surface, thus reducing peptide activity. this peptide must be able to diffuse through the different layers of the assembly to the interface (onaizi and leong 2011) , to ensure efficient release and consequent bioactivity. the diffusion process of the peptide in the different layers is more complex than its diffusion in solution, since additional factors such as tortuosity of the diffusion path, the number of layers, and the polymer-peptide interactions can affect the diffusion process (appendini and hotchkiss 2002; sukhishvili 2005) . covalent bonding. in this process, the antimicrobial peptide will react chemically with a given surface to form a stable bond, which results in the formation of an antimicrobial coating on the polymeric surface (haynie and others 1995) . covalent bonding offers several advantages, including a more stable attachment between the peptide and the polymer surface (goddard and hotchkiss 2007) . covalent bonding reduces attached peptide ability to destabilize and improves its bioactivity, by protecting it from denaturation. due to the inert nature of most polymers, they must be subjected to a functionalization process on the surface before bonding with the peptide. the polymers can be functionalized with different spacers, which are reactive functional groups that allow peptide attachment on the spacer surface (humblot and others 2009) . the quantity of reactive functional groups generated in the functionalization process results in a restricted number of covalent bondings, which limits the amount of peptide that can be attached to the packaging. according to goddard and hotchkiss (2007) , direct bioactive compound applications require small amounts to be effective. however, for the applications of peptides in polymeric matrixes it is necessary to maximize the amount of peptides per unit area. to accomplish this, the functionalization technique must be optimized with the objective of linking the desired type and quantity of reactive functional groups. stiff or flexible spacers have been used as reactive groups for the functionalization of polymers (figure 8 ). stiff spacers, such as polymethyl-methacrylate (pmma) and polyvinyl chloride (pvc), restrict the lateral mobility of the peptide bond, keeping the peptide firmly in a specific orientation. on the other hand, flexible spacers, such as polyethylene glycol (sand and others 2010) allow lateral mobility of the peptide bound, which can result in different orientations of the peptide molecules at the interface (onaizi and leong 2011) . among the different types of spacers, polyethylene glycol (peg) is widely used in the immobilization of peptides. the use of peg has several advantages, such as rapid and free peptide orientation, promoting peptide-bacteria interactions (costa and others 2011) . although the potential penetration and translocation of peptides through the microorganism cytoplasmic membrane is low due to the covalent bond that attaches the peptide to the polymer, it has been reported that peptides have sustained their bioactivity after attachment to polymeric matrixes. the synthetic peptide 6k8l (a peptide sequence derived from magainin) was covalently bound to polystyrene (ps) resin by functionalization with peg and showed antimicrobial activity against foodborne pathogenic microorganisms, including e. coli o157: h7, l. monocytogenes, and pseudomonas fluorescens (appendini and hotchkiss 2001) . similarly, the synthetic peptide e14lkk was covalently immobilized in ldpe film after chromium oxidation and functionalization with peg. this active packaging had antimicrobial activity against e. coli showing a reduction of 3 log cycles when compared with the control (steven and hotchkiss 2008) . the sustained bioactivity of attached peptides is caused by the presence of spacers which allow sufficient freedom of motion for the active portion of the peptide to contact microorganisms on the food surface (appendini and hotchkiss 2002) . haynie and others (1995) have previously demonstrated that peptide-bacteria interactions are sufficient for peptide bioactivity. moreover, costa and others (2011) have indicated that the efficacy of attached peptides could possibly result from a higher peptide-relative surface availability, contrary to the other methods of peptide applications in which peptide aggregation can occur, producing uneven distribution. on the other hand, the diffusion of attached peptides into the food surface is restricted due to the covalent bonding. however, diffusion to the food product can occur in extreme conditions, such as high temperatures, which can promote hydrolysis reactions. the characterization of active packaging involves 2 processes: structural analysis and measurement of their properties (table 4) . according to goddard and hotchkiss (2007) , the type of analytical tool used in the structural characterization of polymers depends on the kind of modification, the specificity required, and available resources. some of the techniques used in structural analysis of active packaging with antimicrobial peptides are the contact angle, x-ray photoelectron spectroscopy (xps), fourier transform infrared spectroscopy (ftir), and scanning electron microscopy (sem). steven and hotchkiss (2008) used the techniques of contact angle and xps to assess changes in the surface of ldpe films after treatment with chromic oxide and functionalization with peg as spacer, subsequently covalently binding a synthetic peptide. the contact angle for the film before being subjected to any process of functionalization showed values of 101 • . however, after chromic oxidation and peg bonding, films presented values of 61 • and 45 • , respectively; which indicated that the film surface became hydrophilic. these researchers concluded that the decrease in the contact angle is the result of an increased ionization at the film surface after oxidation, due to the presence of functional groups, such as carboxylic acid (cooh); and a value even lower after functionalization was observed due to solubility of peg. the xps technique showed changes in chemical composition on the film surface, resulting in the detection of nitrogen (2.6%) and an increased percentage of oxygen (initially from 6.7% to 13.3% after oxidation and 19.4% after functionalization). the oxygen increase was due to the presence of carboxylic acid after chromic oxidation. also, this increase was the result of functionalization with peg due to the main presence of o 2 in the peg chain backbone. in addition, the functionalization with peg also introduced nitrogen originating from its amino-terminal functions (nh 2 -peg-nh 2 ). the ftir spectroscopic technique has been used by pranoto and others (2005) to study the interactions between chitosan films and nisin. they observed an increase in the band of the amide i corresponding to the wave number 1638 cm −1 related to the increased concentration of nisin incorporated in the film. according to the researchers, this is probably due to the interaction between the amine functional groups of chitosan and functional groups of nisin, which resulted in covalent bonds, and consequently in a larger peak. microscopic techniques have also been widely used to evaluate morphological changes in the surface of films that have been incorporated with antimicrobial peptides. pires and others (2008) used sem and observed that cellulose-based films incorporated with nisin, or a mixture of nisin and nantamicin, showed crystals deposited on the surface. these results indicated a heterogeneous distribution of the peptide in cellulosic films, while the control film presented a homogeneous structure. similarly, santiago-silva and others (2009) used sem to observe changes in surface morphology of cellulose acetate film incorporated with pediocin. when the concentration of peptide was increased, the films incorporated with pediocin had a rough surface c 2012 institute of food technologists ® vol. 11, 2012 r comprehensive reviews in food science and food safety 197 table 4 -characterization techniques of packaging incorporated with antimicrobial peptides. technique factor studied structural analysis contact angle quantifies surface hydrophobicity by measuring how far a droplet of water spreads on a surface x-ray photoelectron spectroscopy (xps) determines the atomic composition of the top several nanometers of a solid. this technique can be used to quantify the percent atomic composition and stoichiometric ratios fourier transform infrared spectroscopy (ftir) detects and identifies the chemical functional groups present in the polymer scanning electron microscopy (sem) allows the characterization of the polymer surface morphology and the observation of the dispersion quality of the peptide in the polymeric matrix property measurements mechanical properties measurement of the mechanical performance of the polymer. generally according to the standard method astm d882 (astm 2010a) barrier properties measurement of water vapor permeability. generally according to the standard method astm e96/e96m (astm 2010b); astm f1249 (astm 2006) due to large amounts of pediocin granules dispersed in the matrix. this resulted from the lack of peptide solubility. on the other hand, the control film showed a homogeneous and transparent surface. in addition to the analysis of structural changes and interactions between the peptide and the polymeric matrix, the study of packaging properties is important as well. these properties show the performance of the developed material and how it will relate to the primary functions of food packaging, such as physical integrity. thus, mechanical and barrier properties have become increasingly relevant and are more frequently studied. the mechanical properties of films incorporated with antimicrobial peptides serve as the basis for assessing the effects on the mechanical performance resulting from the modification made to the polymer (table 5) . guiga and others (2009) investigated the effect of nisaplin ® (2.5% purity of nisin) coating on the mechanical properties of laminated films (pe/pa/pe), studying the mechanical properties of elongation at break and young's modulus. their results showed a significant difference in mechanical properties between the films incorporated with the peptide and the control treatment; peptideincorporated films showed an increase of young's modulus and a decrease in elongation at break. the polymer-based coating (hpmc) applied in laminated film, as well as the interaction between proteins and salts present in nisaplin, may have modified the mechanical behavior of the manufactured packaging, thereby increasing the rigidity of the film with the consequent decrease in its elongation. a similar result was observed by santiago-silva and others (2009) in their study of cellulosic films incorporated with pediocin. the researchers indicated that the addition of 25% of the peptide increased the maximum load required for film rupture when compared to the control. the researchers pointed out that a possible interaction between the pediocin and the polymeric matrix allowed the development of a more resistant film. however, a significant drop in the maximum load value was observed at a 50% concentration. according to the researchers, there was an excessive amount of the peptide incorporated, which weakened the cellulose chains of the film and resulted in a reduction of film resistance. a decrease in the mechanical strength of films incorporated with antimicrobial peptides has also been observed. sivarooban and others (2008) reported a decrease in puncture resistance and tensile strength values of soy protein films incorporated with nisin. similarly, pires and others (2008) indicated that nisin incorporated into cellulose-based films affected the film structure, reducing maximum load and elongation values. these resulted from the heterogeneous distribution of the peptide in the polymeric matrix, which consequently lead to the formation of stress points and reduced film resistance. although several studies have indicated changes in film properties, in some cases peptide incorporation into polymeric matrices had no significant effects. massani and others (2008) reported no significant difference in tensile strength, elongation, and water vapor permeability of ldpe films coated with lac-tocin705 and lactocin al705. similar results were observed by chollet and others (2009) who indicated that the incorporation of nisin into pe/pa/pe laminated films, by coating with hpmc, showed neither changes in tensile strength at break nor in water vapor permeability. similarly, guiga and others (2010) reported that the direct incorporation of nisin into multilayer films of ethyl cellulose (ec) and hpmc (ec/hpmc/ec) did not alter the properties of tensile strength, young's modulus, or elongation at break. barrier properties of packaging include resistance to water vapor or gases (o 2 and co 2 ). the water vapor barrier property of the packaging can be determined by calculating the water vapor permeability (wvp) or the water vapor transmission rate (wvtr). both parameters cover the determination of the passage of water vapor through a polymeric material. however, the wvp considers vapor pressure difference between 2 specific surfaces (internal and external) of the analyzed packaging (astm 2010b). both parameters, wvp as well as wvtr, have been used to indicate that the addition of nisin in different polymeric matrixes, such as ldpe film coated with a cellulose-based solution (grower and others 2004; massani and others 2008) , sodium caseinate films (kristo and others 2008) and pe-film coated with hpmc (chollet and others 2009), causes no significant changes in the water vapor barrier property. on the other hand, studies regarding gas permeability in active packaging have been limited due to their applications as films or coatings for food products. during the evaluation and characterization of antimicrobial packaging it is important to research the transference of antimicrobial substances from the packaging material into the food, since this information allows the determination of how the antimicrobial agent is released from the active packaging. the mass transfer can occur by the diffusion mass transfer mechanism or by the convective mass transfer mechanism. the convective mass transfer mechanism occurs in a moving fluid, known as natural convection, if the movement is caused by differences in the density, or as forced convection, if the movement is caused by external agents or when a fluid is flowing on the solid surface by forced movement. on the other hand, diffusion mass transfer consists of a random motion of individual molecules as a result of a concentration gradient (crank 1975; geankoplis 1993) . the migration of substances from packaging materials takes place through the diffusion mass transfer mechanism, since the active packaging and the food contain a concentration gradient for the antimicrobial agent incorporated in the packaging. unlike the research on the release of active substances from drugs or the release of solvents from polymers, the study of antimicrobial release from active packaging is still limited (buonocore and others 2003; bastarrachea and others 2010) . the knowledge of diffusion parameters allows an efficient design of active packaging. several factors must be considered when studying the migration from antimicrobial packaging, including the release rate of the antimicrobial molecules from the packaging. if this rate is high, the active packaging would release the antimicrobial rapidly, resulting in a large concentration at a determined time. however, the large concentration would not be maintained over time, depending on the solubility of the antimicrobial in the selected food. if the solubility is very high, the antimicrobial will migrate rapidly to the food matrix, and therefore result in a decreased concentration of the antimicrobial on the food's surface along time. on the other hand, if the release rate is low, the antimicrobial agent will be slowly released in a desired concentration and if it presents a low solubility in the selected food, the antimicrobial can accumulate on the food surface and slowly migrate into the food matrix. in this situation the release rate should not be slower than the microbial growth (bastarrachea and others 2011) . in either case, the release of the antimicrobial agent from the packing material is indicated by the diffusion coefficient (d). thus, the diffusion characteristics of the antimicrobial agent can be used to determine the amount needed to maintain the proper concentration on the food surface (buonocore and others 2003) . the literature reports a few migration studies of antimicrobial peptides incorporated in active packaging. most evaluate the migration of nisin, probably due to the fact that this is the only antimicrobial peptide substance indicated as generally recognized as safe (gras) for direct contact with food in the united states (fda 2011). nisin is also widely accepted as a food preservative in the european community where it is classified as a safe preservative for food contact, coded as e 234 (fsa 2010), as well as in brazil where the use of nisin is permitted by brazilian law as a natural preservative for biological products (anvisa 1996) . diffusion of several antimicrobial agents, such as potassium sorbate or lysozyme incorporated in active packaging, has been explained by fick's second law (han and floros 1998; gemili and others 2009) : where, c is the diffusing substance concentration; d is the apparent diffusion coefficient; t is the diffusion time; and x the distance. depending on the conditions of the migration test, different analytical solutions have been applied to solve fick's second law and to calculate the d-value in the migration of the antimicrobial peptide nisin incorporated in different types of packaging materials (table 6) . different analytical solutions of fick's second law have been used in previous studies to calculate the d-value of nisin at a specific temperature ( table 7) . some of these studies were conducted at different temperatures to characterize the d-value as a function of this parameter. protein films (corn zein or wheat gluten) and poly(butylene adipate-coterephthalate) (pbta) films incorporated with nisin showed an increase in d-value with increasing temperature, indicating that the peptide concentration was higher in the simulant at equilibrium state with increasing temperature (teerakarn and others 2002; bastarrachea and others 2010) . similarly, at low temperatures, lower d-values of nisin diffusivity indicate that the film retains larger amounts of the peptide in the polymer matrix while in contact with the simulant. the arrhenius activation energy model (eq. 2) has been shown to confirm the dependence of the diffusivity with respect to temperature. where, d 0 is a constant; e a is the activation energy for the diffusion process (j/mol); r is the universal gas constant (8.314 j/mol k); and t abs is the absolute temperature (k (−1) n ierfc nh 2 √ d t m 0 , is the initial amount of nisin in the film; m t , released amount of nisin at time t; h, film thickness; d, diffusion coefficient; ierfc, associated function of the mathematical error function teerakarn and others (2002) paper coated with acrylic polymer and ethylene-vinyl acetate co-polymer (eva) is the amount of nisin released at time t; m ∞ , is the migration in a state of equilibrium; l p coating layer thickness, d, diffusion coefficient kim and others (2002) hydroxypropyl methyl cellulose (hpmc) films is the amount of nisin in the simulant at time t; m f,0 , amount of nisin in the film when t = 0; α, mass ratio between the amount of nisin in the simulant and in the film at equilibrium; q n , is the ''n" root of tanq n = −αq n ; l, is a half of the film's thickness bastarrachea and others (2010) teerakarn and others (2002) indicated e a values of 85.8 and 53.1 kj/mol for corn zein and wheat gluten films, respectively, and bastarrachea and others (2010) obtained an e a value of 38.3 kj/mole for pbta film incorporated with nisin. the value of e a represents the degree of molecular interactions between the antimicrobial substance incorporated and the polymeric matrix. thus, higher e a values represent stronger antimicrobial-polymer interactions, which is reflected in a lower d-value due to the greater energy level required for antimicrobial release (bastarrachea and others 2010) . the relationship between temperature and diffusivity of the antimicrobial agent is the result of structural changes in the polymer matrix, since above the glass transition temperature (t g ) the molecular mobility in the system increases along with temperature, which leads to an increase in the ability of the packaging material to transport substances through its polymeric matrix (teerakarn and others 2002) . in addition to the interactions between polymer and antimicrobial agent, the d-value is also influenced by interactions between the antimicrobial and the food matrix. thus, the food nh2-r-w-c-f-r-v-c-y-r-g-i-c-y-r-k-c-r-conh2 miyata and others (1989) * x = means that the specific identity of an amino acid cannot be determined unambiguously. * * dhb = (z)-2,3-didehydrobutyrine. * * * abu = 2-aminobutyric acid. composition, as well as the solubility of the antimicrobial in these components also affects the d coefficient. in the study of paper coated with eva incorporated with nisin, the d-values varied according to the composition of the food in contact with the active packaging (kim and others 2002) . the highest d-value was observed when the film was in contact with a 2% citric acid solution, and the lowest value was observed when in contact with a 2% nacl solution. characteristic parameters of each solution, such as ph and ionic strength, have been shown to influence nisin solubility. nisin has a high solubility (up to 40 mg·ml −1 at ph 2) at low ph, but at high concentrations of nacl (above 1 m) nisin solubility dependence on ph almost disappears and the solubility decreases to values below 1 mg·ml −1 at any ph (rollema and others 1995) . chollet and others (2009) also investigated the influence of food composition on the migration of nisin incorporated in pe/pa/pe films coated with hpmc by changing the fat percentage. they found that increasing the fat content in the food resulted in an increased d-value and, therefore, in a greater diffusion of incorporated nisin. in their experiment, nisin diffusion mechanism was governed by the fat content. the increase in fat content resulted in microstructural changes, such as enlargement of pore size in the food matrix, which favored nisin diffusion into it. consumer demand for minimally processed foods and additivefree products has led to the development of antimicrobial packaging. peptides have shown various bioproperties, among them antimicrobial activity, leading to the application of these compounds in the food preservation area by either direct addition or incorporation into packaging materials (table 8) . active packaging materials incorporated with antimicrobial peptides have shown effectiveness in inhibiting pathogenic microorganisms, an improvement in food safety. moreover, antimicrobial peptides incorporated into the polymeric matrix may af-fect the engineering characteristics of the packaging material, and lead to differentiated diffusion performance. this review highlights the characteristics of pure peptides, as well as their incorporation into polymeric matrices. several studies have indicated significant changes in mechanical properties and surface morphology of the films incorporated with antimicrobial peptides. however, research related to the study of barrier properties to gases and water vapor is still limited. more studies on the release of other peptides, different from nisin, from food packaging materials are needed to better understand the mechanism of dissemination of antimicrobial agents. finally, in the years ahead, the advent of nanotechnology will lead to research on the synergistic effects of antimicrobial peptides and nanoparticles, such as metals, metal oxides, and nanoclays, with the objective being to improve the mechanical and barrier properties of antimicrobial packaging. bioactive peptides: synthesis, properties, and applications shortened cecropin a-melittin hybrids significant size reduction retains potent antibiotic activity uso da nisina com a função de conservador para queijos pasteurizados. portaria deten/ms n • 29, de 22 de janeiro de 1996 surface modification of poly(styrene) by the attachment of an antimicrobial peptide review of antimicrobial food packaging in: standard test method for water vapor transmission rate through plastic film and sheeting using a modulated infrared sensor astm d882 in: standard test method for tensile properties of thin plastic sheeting astm e96/e96m in: standard test methods for water vapor transmission of materials biochemical and genetic characterization of enterocin a from enterococcus faecium, a new antilisterial bacteriocin in the pediocin family of bacteriocins engineering properties of polymeric-based antimicrobial films for food packaging: a review release kinetics of nisin from biodegradable poly(butylene adipate-co-terephthalate) films into water detergent-like actions of linear amphipathic cationic antimicrobial peptides optimized enzymatic synthesis of c-terminal peptide amides using subtilisin a from bacillus licheniformis recent applications of enzymatic peptide synthesis chemical synthesis of proteins a general approach to describe the antimicrobial agent release from highly swellable films intended for food packaging applications tilapia (oreochromis mossambicus) antimicrobial peptide, hepcidin 1-5, shows antitumor activity in cancer cells a fish antimicrobial peptide, tilapia hepcidin th2-3, shows potent antitumor activity against human fibrosarcoma cells antimicrobial peptides (amp) with antiviral activity against fish nodavirus buforins: histone h2a-derived antimicrobial peptides from toad stomach monitoring nisin desorption from a multi-layer polyethylene-based film coated with nisin-loaded hpmc film and diffusion in agarose gel by an immunoassay (elisa) method and a numerical modeling reference method for broth dilution antifungal susceptibility testing of yeast performance standards for antimicrobial disk susceptibility tests methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically bioactive packaging technologies for extended shelf life of meat-based products covalent immobilization of antimicrobial peptides (amps) onto biomaterial surfaces the mathematics of diffusion antibiotic magainins exert cytolytic activity against transformed cell lines through channel formation in vitro antiplasmodium effects of dermaseptin s4 derivatives hydrophobicity, hydrophobic moment and angle subtended by charged residues modulate antibacterial and haemolytic activity of amphipathic helical peptides antifungal peptides: novel therapeutic compounds against emerging pathogens antiviral effects of synthetic membrane-active peptides on herpes simplex virus, type 1 the possible roles of food-derived bioactive peptides in reducing the risk of cardiovascular disease direct food substances affirmed as gras -electronic code of the bactericidal activity of pediocin pa-1 is specifically inhibited by a 15-mer fragment that spans the bacteriocin from the center toward the c terminus food standards agency. current eu approved additives and their e numbers defensins: antimicrobial peptides of innate immunity immunomodulatory peptides obtained by the enzymatic hydrolysis of whey proteins principles of mass transfer development of cellulose acetate-based antimicrobial food packaging materials for controlled release of lysozyme polymer surface modification for the attachment of bioactive compounds development and characterization of an antimicrobial packaging film coating containing nisin for inhibition of listeria monocytogenes antimicrobial plastic film: physico-chemical characterization and nisin desorption modeling innovative multilayer antimicrobial films made with nisaplin ® or nisin and cellulosic ethers: physico-chemical characterization, bioactivity and nisin desorption kinetics simulating diffusion model and determining diffusivity of potassium sorbate through plastics to develop antimicrobial packaging films the role of cationic antimicrobial peptides in innate host defences antimicrobial and host-defense peptides as new anti-infective therapeutic strategies antimicrobial activities of amphiphilic peptides covalently bonded to a water-insoluble resin a coating for use as an antimicrobial and antioxidative packaging material incorporating nisin and [alpha]-tocopherol studies on anticancer activities of antimicrobial peptides the antibacterial activity of magainin i immobilized onto mixed thiols self-assembled monolayers proteomics for studying cancer cells and the development of chemoresistance antifungal properties and mode of action of psacotheasin, a novel knottin-type peptide derived from psacothea hilaris antifungal activity of synthetic peptide derived from halocidin, antimicrobial peptide from the tunicate, halocynthia aurantium peptide antimicrobial agents chemical synthesis of peptides and proteins properties of nisin-incorporated polymer coatings as antimicrobial packaging materials bioactive peptides: production and functionality thermal, mechanical and water vapor barrier properties of sodium caseinate films containing antimicrobials and their inhibitory action on listeria monocytogenes antifungal mechanism of smap-29 (1-18) isolated from sheep myeloid mrna against trichosporon beigelii antitumor activity of the antimicrobial peptide magainin ii against bladder cancer cell lines virucidal activity of a scorpion venom peptide variant mucroporin-m1 against measles, sars-cov and influenza h5n1 viruses recombinant production of antimicrobial peptides in escherichia coli: a review peptide-derivatized dendrimers inhibit human cytomegalovirus infection by blocking virus binding to cell surface heparan sulfate sínteses química e enzimática de peptídeos: princípios básicos e aplicações high-pressure processing and antimicrobial biodegradable packaging to control listeria monocytogenes during storage of cooked ham development and characterization of an active polyethylene film containing lactobacillus curvatus crl705 bacteriocins relationship of membrane curvature to the formation of pores by magainin 2 antimicrobial peptides, isolated from horseshoe crab hemocytes, tachyplesin ii, and polyphemusins i and ii: chemical structures and biological activity antiviral activity of selected antimicrobial peptides against vaccinia virus mammalian cell toxicity and candidacidal mechanism of arg-or lys-containing trp-rich model antimicrobial peptides and their d-enantiomeric peptides purification and characterization of plantaricin a, a lactobacillus plantarum bacteriocin whose activity depends on the action of two peptides the antiviral activity of naturally occurring proteins and their peptide fragments after chemical modification peptide synthesis catalyzed by organic solvent-stable protease from pseudomonas aeruginosa pst-01 in monophasic aqueous-organic solvent systems tethering antimicrobial peptides: current status and potential challenges selective lysis of bacteria but not mammalian cells by diastereomers of melittin: structure-function study broth microdilution antibacterial 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sorbate and nisin applications of antimicrobial peptides from fish and perspectives for the future antimicrobial peptides: premises and promises peptide purity and counter ion determination of bradykinin by high-performance liquid chromatography and capillary electrophoresis improvement of solubility and stability of the antimicrobial peptide nisin by protein engineering antimicrobial and antifungal activities of a novel cationic antimicrobial peptide, omiganan, in experimental skin colonisation models plantaricin a, a peptide pheromone produced by lactobacillus plantarum, permeabilizes the cell membrane of both normal and cancerous lymphocytes and neuronal cells antimicrobial efficiency of film incorporated with pediocin (alta ® 2351) on preservation of sliced ham antioxidative peptides from food proteins: a review development of bioactive food packaging materials using immobilised bacteriocins lacticin 3147 and nisaplin ® bioactive peptides: synthesis, properties, and applications health-related costs: from foodborne illness in the united states. produce safety project. available from: www.producesafetyproject.org. accessed cationic amphiphilic peptides with cancer-selective toxicity controlled diffusion of an antimicrobial peptide from a biopolymer film application of bacteriocins in vegetable food biopreservation synthesis and application of caged peptides and proteins physical and antimicrobial properties of grape seed extract, nisin, and edta incorporated soy protein edible films lipase-catalyzed synthesis of peptides containing d-amino acid: facts and artifacts recent patents on active packaging for food application active and intelligent packaging for milk and milk products membrane fluidity characteristics of human lung cancer heparan sulfate: anchor for viral intruders? immunomodulatory activity of small peptides covalent immobilization of an antimicrobial peptide on poly(ethylene) film responsive polymer films and capsules via layer-by-layer assembly nisin diffusion in protein films: effects of film type and temperature influence of amino acid substitutions in the nisin leader peptide on biosynthesis and secretion of nisin by lactococcus lactis antiviral activities of lactoferrin natural products with hypoglycemic, hypotensive, hypocholesterolemic, antiatherosclerotic and antithrombotic activities expression and purification of antimicrobial peptide buforin iib in escherichia coli lantibiotics: peptides of diverse structure and function mechanism of interaction of different classes of cationic antimicrobial peptides with planar bilayers and with the cytoplasmic membrane of escherichia coli barrel-stave model or toroidal model? a case study on melittin pores antimicrobial peptides of multicellular organisms interaction of the antimicrobial peptide pheromone plantaricin a with model membranes: implications for a novel mechanism of action the authors would like to thank to nicholas j. walker for providing language help and writing assistance. financial support for this research was provided by coordenação de aperfeiçoamento de pessoal de nível superior (capes) and the conselho nacional de desenvolvimento científico e tecnológico (cnpq). key: cord-293974-jcpkla55 authors: simões, marta filipa; ottoni, cristiane angélica; antunes, andré title: mycogenic metal nanoparticles for the treatment of mycobacterioses date: 2020-09-02 journal: antibiotics (basel) doi: 10.3390/antibiotics9090569 sha: doc_id: 293974 cord_uid: jcpkla55 mycobacterial infections are a resurgent and increasingly relevant problem. within these, tuberculosis (tb) is particularly worrying as it is one of the top ten causes of death in the world and is the infectious disease that causes the highest number of deaths. a further concern is the on-going emergence of antimicrobial resistance, which seriously limits treatment. the covid-19 pandemic has worsened current circumstances and future infections will be more incident. it is urgent to plan, draw solutions, and act to mitigate these issues, namely by exploring new approaches. the aims of this review are to showcase the extensive research and application of silver nanoparticles (agnps) and other metal nanoparticles (mnps) as antimicrobial agents. we highlight the advantages of mycogenic synthesis, and report on their underexplored potential as agents in the fight against all mycobacterioses (non-tuberculous mycobacterial infections as well as tb). we propose further exploration of this field. currently, there are almost 200 described species of the ubiquitous acid-fast bacteria of the genus mycobacterium [1] . mycobacteria can cause many different mycobacterioses, being the most worrying tuberculosis (tb) [1] , while common mycobacterioses can be caused by non-tuberculous mycobacteria (ntm). some ntm such as mycobacterium abscessus, m. avium, m. kansasii, m. malmoense, and m. xenopi can cause pulmonary diseases; others like m. chelonae, and m. haemophilum are able to cause disseminated diseases; furthermore, m. fortuitum, m. marinum, and m. ulcerans are able to cause skin, soft tissue, and bone diseases [2] . even though there are some pathogenic species, ntm are opportunistic and considered as nontransmissible [3, 4] . the distinction between pathogenic and non-pathogenic species is not always trivial as many of them share the same phenotypic and genotypic characteristics and have very limited differences [3, 5] . despite their similarities, ntm have lower human pathogenicity than mycobacteria from the mycobacterium tuberculosis (mtb) complex [6, 7] (species with 85-100% dna homology with mtb, which include m. africanum, m. bovis, m. caprae, m. canetti, m. pinnipedii, m. tuberculosis, m. microti, or m. mungi, which are all pathogenic [3, 7, 8] ). the fact that ntm share many infectious traits with the causing agents of tuberculosis (tb) allows them to be used in many research studies as model organisms of infection for this disease, with the advantage of being less pathogenic and faster growing species [7, 9] . relation with similar clinical symptoms. therefore, aspergillosis has long been reported to lead to tb misdiagnosis [23] [24] [25] . when there are co-infections or direct links between tb and inflammation of cells due to other diseases, further challenges become evident: therapeutic limitations, acquired resistance, toxic side-effects, and drug-drug interactions [26, 27] . a disease for which tb has been referred as a risk factor is lung cancer, since it can cause alterations in the lungs, which might become a cause for later malignant cell changes [27] . the coronavirus disease 2019 (covid-19) pandemic is having a huge social impact. outcomes of this pandemic include the reduction or suppression of certain healthcare infrastructures and their access, mainly due to lockdown and other control measures (quarantine of suspected cases, isolation of infected patients, and contact tracing). as a result, less cases of tb will be detected, and its infection rate will increase [28] . the lockdown also affects the production and transport of drugs and supplies, and limits the access to healthcare services, causing the disruption of treatments of certain diseases, which will be particularly negative for people with drug-resistant tb [29] . this will certainly worsen the problem of resistance in tb and other infections. confinement also facilitates the contact of infected and non-infected members that share the same house, thus increasing household transmission of tb [30] . both tb and covid-19 present similar and non-specific clinical features-fever, cough, and dyspnea, or breathlessness [15, 31, 32] . when covid-19 testing is not available, their similarities can easily lead to misdiagnosis and ineffective treatments [30, [32] [33] [34] . another potential challenge is the stigmatization of tb patients (for coughing), due to the fear of covid-19 [30, 31] . these patients become afraid of visiting healthcare services, and many (infected with tb) end-up not being properly diagnosed within a timeline that would contribute to control the infection [31] . cases of patients simultaneously infected with tb and covid-19 present other risks: when radiology data is not available, tb might not be diagnosed; covid-19 therapy can reactivate latent tb; pre-existing tb, especially if active, will worsen the clinical state of covid infection; and the simultaneous therapy for both infections can lead to drug-drug interactions and added hepatotoxicity [32] . the who has recognized the impact of covid-19 on tb and has issued a note on how to tackle this serious issue [15] . nevertheless, some of these negative consequences will be unavoidable and long-lasting [16, 35] . as a result of the pandemic, the next five years are expected to reverse the trend of the past decades [29] and will lead to an increase in tb incidence and mortality [36] . the common treatment for tb is a multidrug combination of first-line drugs, consisting of two months of rifampicin (rif), isoniazid (inh), pyrazinamide (pza) and ethambutol (emb), followed by four months of rif and inh [6, 10, 37] . these standard combinations are reasonably low-priced and effective against sensitive mycobacterial strains [9] . however, due to the long duration and toxic side-effects of the therapy (especially when treating drug-resistant cases), many patients end-up not following the complete treatment, thus increasing the chance of reemergence of the disease and development of resistance [10, 14, 38] . unfortunately, the six-month treatment is not effective against mdr nor xdr tb [39] . mdr tb implies simultaneous resistance to rif and inh, whereas xdr tb implies an additional resistance to a quinolone and at least one injectable drug [17] . the increasing number of cases of mdr and xdr tb lead to the use of second-line drugs which are more toxic and less effective than first-line ones [17] . the treatment of mdr tb is more expensive, longer (can go up to 24 months), and uses a combination of at least five drugs with many harmful secondary effects (such as hepatotoxicity) [40] . failure of treatment hardens the challenge of fighting tb because it increases the infection rate and raises mortality [39] ; 70% of xdr tb patients have been estimated to die within a month of diagnosis [14] . therefore, all options that can contribute to improve efficiency of antimycobacterial activity and reduce toxicity should be fully explored. carrier or delivery systems, such as liposomes and microspheres, have been developed for the sustained delivery of anti-tb drugs and have shown better chemotherapeutic efficacy [17, 41] . conjugating existing drugs with nps is another strategy that has great potential for the treatment of mdr tb. this is the case of mesoporous silicon nps conjugated with ethionamide (eth), a second-line drug, that has increased activity against mtb when compared to eth alone [42] . hakkimane and colleagues synthesized nps with poly lactic-co-glycolic acid polymers encapsulating rif or inh, and found both formulations to be more effective than rif or inh against mtb, having a higher activity and requiring a lower drug concentration [39] . chemical synthesis of new drugs, such as prodrugs derived from first-line agents, is another strategy also studied as an alternative solution to fight tb where different chemical structures might circumvent previous resistance [43] . some peptides, part of the host first-line of defense and produced by the innate immune response, have been identified as having antimicrobial activity, presenting good biocompatibility and low probability of leading to microbial resistance [44] . these have been described as having a direct action against microorganisms, by creating cytotoxic pores on their cell walls, and an indirect one, by modulating the host immune system through upregulated secretion of pro-inflammatory cytokines and chemokines and contributing to contain infection [44] [45] [46] . therapies using these antimicrobial peptides have been investigated, and synthetic peptides have been shown to have great potential and activity against pathogens, combined with decreased toxicity [46, 47] . however, despite all this research and promising leads, their application to tb therapy remains underwhelming and a completely effective tb vaccine has also not yet been developed [14] . the current research was developed according to the prisma protocol. a literature search was performed on three databases (research gate (www.researchgate.net), google scholar (https://scholar.google.com), academia (www.academia.edu), and further cross-checked and complemented with searches on web of science (www.webofknowledge.com), scopus (www.scopus. com/home.uri), and pubmed (https://pubmed.ncbi.nlm.nih.gov). the search criteria were based on the following key terms: nanoparticle, mycogenic, biologic, mycobacterium, and agnps. searches with all possible combinations of the referred terms were performed. selected articles included all of those mentioning the use of mycogenic metallic nanoparticles against mycobacteria, as well as the most recent (≈last decade) manuscripts on agnps. the last date for these searches was 4 august 2020. any article matching the searching criteria was checked and used in our review. the rise of microbial resistance against antimicrobial drugs has encouraged and promoted nanotechnology research as a potential viable source of solutions [48] . np-based systems are able to circumvent many of the challenges related to mycobacterial infections since they can target the infected cells and act directly on the cell wall of intracellular pathogens, as is the case of mtb when it infects macrophages in pulmonary tb [26] . it is common knowledge that metal nanoparticles (mnps) have antimicrobial activity against a multitude of microorganisms [40] . mnps represent promising potential solutions against many infections and resistance to traditional drugs. they use different mechanisms of action from those identified for common drugs, exhibit activity against many microbial resistant species and strains, and target several biomolecules interfering in the development of microbial resistance [49] . the mechanisms that have been reported to explain the effects of mnps on microbial cells include: dna damage, protein damage, mitochondrial damage, attachment to 30s ribosome subunit, oxidation of cellular components, release of metal ions, damage to the proton efflux pump, disruption, or prevention of biofilm formation, disruption of cell membrane, disruption of transmembranar electron transport, and production of reactive oxygen species (ros) [17, 49] . some of these mechanisms vary depending on the target species and the specific characteristics of the nps [17] . silver (ag) has the highest reflectivity of all metals [50] . it has been used for centuries as an antimicrobial agent [40] . throughout history, civilizations incorporated silver into daily life objects to avoid spreading diseases, for example, in ancient times, silver containers were used to keep water potable and prevent wine spoilage. however, once antibiotics were discovered, the use of silver for its antimicrobial activity decreased [50] . nowadays, nanotechnology is responsible for a resurgence in the exploration of silver for these purposes. agnps are the most widely used mnps due to their potential as therapeutic agents and antimicrobial agents, showing activity against almost 700 pathogens [19, 51] . agnps are used in a vast number of different products and applications (namely textiles, cosmetics, food packaging, medical appliances, pharmaceutical ointments among many others) [40, 50, 52] . they have a significant impact on respiratory medicine and can be applied against a broad range of microbial infections [27, 52] . agnps are an alternative way to overcome drug resistance [53] , mostly due to their particular characteristics: small size, even morphology, and capacity to interact with biomolecules [19] . furthermore, agnps have been reported as having good conductivity, chemical stability, catalytic activity, cytotoxic effect on cancer cells, and antimicrobial activity [49, 54] . agnps have proven antimycobacterial activity, but this activity is highly variable, dependent on several parameters [52] , and also on target species [26, 53, 55] . smaller agnps tend to have higher activity due to their larger surface/area, which allows them to release higher amounts of silver ions and inhibit microbial growth [26, 56] . in addition, higher concentrations lead to higher activity [55, 57] . some studies also point to the potential relevance of agnps shape, although this has only been rarely analyzed. triangular-shaped agnps seem to be more effective against escherichia coli, likely due to an increase in positive charges and more active facets induced by this morphology [58, 59] . although agnps' antimicrobial mechanism of action is not fully clear, we know that they kill by contact and ion release [19] . it was also detected that the antimycobacterial activity of agnps is higher than other metallic nps, making them a favorite focus on this research field [40, 56, 60] . furthermore, in addition to antimycobacterial properties in vitro-when applied directly on mycobacteria, agnps have also shown ex vivo activity by suppressing innate responses of infected macrophages, induced by mycobacteria [40] . mycogenic agnps have also been reported to have anti-inflammatory activity [54] . all of the characteristics of agnps make them an undoubtedly easy focus of nanotechnology research. an overview of recent research on the use of agnps against mycobacterial species, not including mtb, is presented below ( table 1 ). this overview excludes mtb which will be analyzed afterwards due to its epidemiological relevance. we can note that the majority of these studies relied on chemically synthesized agnps. furthermore, they have focused on a reduced number of species, the most common being m. smegmatis and m. bovis. the reasoning for this focus is the fact that m. smegmatis is the most used model organism for the study of mycobacteriosis and tb, as they are safe and non-pathogenic mycobacteria as well as fast-growing and easy to manipulate genetically [61] . m. bovis (strain bcg) is a slow-growing mycobacterium, whose choice as a model is mostly due to its placement within the mtb complex, being an attenuated strain and a biohazard level 2 microorganism (versus biohazard level 3 for mtb) [62] . only a few studies have looked specifically into the production of agnps against mtb (table 2 ). these include agnps produced via physical-chemical methods, as well as biological ones (mostly using parts of plants), and consist of a wide-range of np sizes and tested strains (avirulent, virulent, isolated from clinical samples, drug-sensitive and drug-resistant-mdr and xdr). the research made so far on the use of agnps against mtb has proved that these are effective. the lack of standardization among all research studies makes it more difficult for us to compare them across, although they provide some relevant insights into the use of this type of nps against mtb. the general consensus that smaller sized agnps are more active against bacteria is also valid for mycobacteria [56, 71] . this is the case, for example, of the smaller bsa-agnps ( table 2 ) that showed higher activity than the produced pvp-agnps [64] . furthermore, these studies present promising results with cases of activity reported against mdr and xdr strains [19, 26, 71, 72, 78] , as well as activity against intracellular mtb [56, 73] . this is especially relevant for latent tb where mtb remain inside granulomas [79] , where they adapt and thrive under adverse conditions, such as nutrient deprivation and hypoxia [3] . mycogenic processes are biological processes developed by fungi, mostly filamentous fungi (molds)-fungi that form mycelia. these organisms have the capacity to accumulate metals by sequential action of reductase enzymes (such as nadph-dependent nitrate reductase), leading to the reduction of metal salts and final production of metal nanoparticles (mnps) [58] . as such, they can be affected by several parameters (table 3) . resultant morphology (size). • smaller concentrations tend to lead to smaller mnps and increased dispersion. higher concentrations can generate increased toxicity. culture media quantity of mnps. • media containing enzymes-specific substrates increases enzyme production, which can generate more mnps. quantity of mnps. • more biomass leads to increased enzyme release, facilitating the mycosynthesis of mnps and increasing their production. resultant morphology (size), quantity of mnps, and synthesis rate. • little or no agitation decreases the synthesis rate and might lead to agglomeration, increased sizes, and reduced mnp production. light intensity quantity of mnps and synthesis rate. • light stimulates fungal growth and metabolite production. higher metabolite concentration results in faster synthesis and increased mnp production. these parameters can be adjusted and optimized. they are variable for some processes and for the species used for the production of mnps [52] . interestingly, the mnps used in in vitro assays don't have their antimicrobial activity affected by temperature or ph [17] . however, the full extent of the effects of these parameters (table 3) is not yet completely understood and requires further research. even though mycogenic mnps can be produced intra-or extracellularly, the latter production process is more appealing. extracellular production involves fewer steps and does not require cell disruption to release the mnps or complex washing steps to recover and purify them [17] . many studies have reported and listed the capacity of different fungal species to synthesize mnps, from ubiquitous groups, to extremophiles, and ranging from yeasts, to filamentous fungi and mushrooms [18, 54, 58, [80] [81] [82] [83] [84] [85] [86] . despite this wide diversity, most mycogenic processes rely on filamentous fungi and follow a four-main steps method ( figure 1 ). generally, the process includes the growth of fungal biomass (steps i and ii in figure 1 ), followed by a sequential shorter incubation of that biomass in water (step iii in figure 1) , and then the mixture of this supernatant with a chemical precursor (step iv in figure 1 ). the fungal metabolites act as reducing and stabilizing agents, and lead to the reduction of metal ions and agglomeration of metal atoms, which result in mnps. the mnp synthesis is noticeable by the change in the color of the suspension and can be further confirmed by uv-visible spectroscopy, which detects changes in the optical properties of the mnps, by reading the absorbance of the surface plasmon resonance bands (usually localized at a wavelength of 400-450 nm). the mnp suspension should then be cleaned and purified either by filtration, dialysis, or ultracentrifugation. the last few years have shown a considerable amount of research and development in the use of mycosynthesis of the most studied mnps-agnps (supplementary table s1 ). these further highlight their wide applicability and support the use of mycogenic agnps as antimicrobial agents as well as for all other applications of general mnps [48, 55, [87] [88] [89] [90] [91] [92] [93] [94] [95] [96] [97] [98] [99] [100] [101] [102] [103] [104] [105] [106] . most mycogenic agnps studied are spherical although some variations, mostly due to the formation of clusters, can also be found [41] . in most mycogenic processes (those following the method shown in figure 1 ), the common concentration of the precursor-silver nitrate (agno 3 )-is 1 mm [48, 89, 103, 106] . within the size variation described, mycosynthesized agnps when produced with enzymatic stimulation (from co-cultures) form smaller and more active nps [106] . mycogenic synthesis of agnps combines the best of both worlds: the most effective mnps that nanotechnology has developed together with the green production process mediated by fungi [80] . these mycogenic processes allow us to obtain smaller sized nps than those produced as a result of chemical or physical synthesis, which in turn allow a better control over production size, being less size-variable [83] . furthermore, synthesis parameters can be altered in order to change their size and therefore activity [52, 54] . so far, little has been explored combining the use of mycogenic agnps and the fight against tb and other mycobacterioses, but the efforts presented in table 4 show the potential to exert some control over this infection and its increasing resistance. in general, mycogenic mnps are mostly monodispersed, with well-defined size and shape (which is most commonly spherical) [85] . moreover, the mycogenic agnps reported to be successful against mycobacteria were obtained from a diverse range of fungi, which included yeasts and species within different families of filamentous fungi (table 4 ). this supports the assumption that fungi constitute a potential source of mnps relevant for fighting tb and other mycobacterioses. biological agnps are considered relatively safe and less toxic (less cyto/genotoxic in vivo) than chemically synthesized agnps [110, 111] . their toxicity depends on the concentration used [112] . in addition, generally, all agnps show increased toxicity once dissolved and after losing their spherical structure [49] . transition metals (the 38 elements in groups 3 through 12 of the periodic table) are recognized as the most suitable elements for the synthesis of mnps [49] . within these, nps incorporating silver are the most widely studied and used. the last few years have seen an increase in testing some of the other transition metals and others as a way of uncovering new mnps and exploring their potential use as antimicrobial compounds ( table 5 ). the study of mnps with alternative metals against mycobacteria is arguably less dynamic. nonetheless, a few researchers have investigated the use of elements such as copper, gallium, selenium, titanium, zinc, or even bimetallic alternatives. within these, copper and zinc seem to be the two transition metals most commonly explored, with gallium (a post-transition metal) also being frequently studied. exploring these alternatives can be relevant to better understand which mnps have lower probability of developing toxicity. many studies have focused on the use of mnps complemented with other substances or different mnps (table 6 ). such combined uses of mnps have often proved to be synergetic, increasing the antimicrobial activity of its individual components. both citrate-aunps and pah-aunps have activity against m. bovis (strain bcg), lower than tested agnps [66] copper (cunps) nr biologically synthesized from leaves of psidium guajava l. activity against mtb, m. smegmatis, and m. pheli, but lower than other mnps [57] gallium (ganps) 305 nm sized and cylindrical chemically synthesized by double emulsification and sonication polydispersed, with prolonged activity against intracellular m. smegmatis [113] copper oxide and zinc oxide (cu(ii)onps and znonps) spherical chemically synthesized activity against m. avium subsp. paratuberculosis [69] 10-70 nm sized and polydispersed phyto-synthesized from barleria prionitis 90 nm sized and hexagonal phyto-synthesized from plumbago zeylanica 10-20 nm sized and spherical phyto-synthesized from syzygium cumini 16 µg/ml) higher activity than aunps or agnps (mic ≈ 2.5 µg/ml), and more specific for mycobacteria with a higher selectivity index in addition, the smaller mnps (from s. cumini) are more effective [60] zinc oxide (znonps) 12-53 nm sized and spherical biologically synthesized from leaves of limonia acidissima linn. also known as feronia elephantum correa or wood apple activity against mtb (strain h37rv) [114] ganps ≈300 nm sized and cylindrical chemically synthesized by double emulsification and sonication activity against intracellular mtb (strain h37ra) in monocyte-derived macrophage (mdms) and thp-1 macrophages (up to 70% mtb growth inhibition) [115] zinc (znnps) ≈60 nm sized and variable shapes, mostly spherical biologically synthesized from pseudomonas hibiscicola combination therapy for mycobacterial infections can increase the potential activity of mnps, contribute to decrease the effective dose of antibiotics potentiating them; reduce side effects, drug toxicity, and mnps toxicity; enhance bioavailability; and enhance solubility and retention time [103, 124] . the exact interaction mechanisms aren't always fully understood. generally, negatively charged microbial surfaces attract positively charged mnps due to electrostatic interactions. the mnps then establish bonds with the cellular membranes, disrupting the cell walls and making them more permeable. as a consequence, microorganisms become more sensitive to drugs [49] . the increased activity from the conjugation of mnps with antimicrobial peptides, for example, might be due to the higher membrane permeability of the peptides, which then help deliver mnps into the microbial cells [44] . another example of increased antimycobacterial activity is the combination of agnps with chloroform, which is due to chloroform's ability to remove lipids and rupture the mycobacterial cell wall [41] . one should also note that the conjunction of biomolecules such as peptides or chitosan results in increased antimycobacterial activity, but this effect is limited after mycobacteria are internalized by macrophages [7] . more effective strategies rely on combining nps with classical anti-tb therapeutics that ensure both extra-and intracellular activity, although only a few in vivo studies have explored this option [7] . the increased applications of mnps in the medical field demand more biocompatible, safe, and effective nanostructures with less hazardous byproducts of synthesis reactions [83] . mycogenic mnps (as well other biological mnps) are regarded as safe, less toxic, biocompatible, eco-friendly, and cheaper alternatives, with lower consumption of energy and higher yields when compared with physical-chemical synthesis [56, 106] . fungi are more efficient than most microorganisms when it comes to the biological production of mnps [51] . this is due to the fungal capacity of producing a high number of bioactive metabolites, accumulating metals and having enhanced processes [54, 125] . as additional advantages, fungi are easy to manipulate, easy to grow, do not require complex nutrients, have high production of biomass and metabolites, and have high wall-binding capability and high metal uptake [52, 80, 83, 85, 89, 106, 126] . many of the fungal metabolites involved in the mycogenic synthesis also cap the mnps, conferring a higher control of size and stability. in addition, because most mycogenic processes are extracellular, there is no requirement for additional steps, or downstream processing, to release the mnps for further processing or use [49, 80] . moreover, extracellular mycogenic processes facilitate handling and scale-up, and mycelia from filamentous fungi are more resistant to agitation and pressure making them more suitable for large-scale synthesis in bioreactors and chambers [54, 106] . looking specifically at mycogenic agnps, a recent study observed that they were more active against pathogenic bacteria than chemically synthesized agnps [55] , further highlighting the advantages of their use. a wide variety of fungal genera are recognized as being able to precipitate agnps (namely aspergillus, fusarium, penicillium and verticillium) [126] . however, there is a much wider fungal diversity that remains completely unexplored. current estimates point to the existence of 1.5-3.8 million fungal species on earth with only 120,000 (3-8% of the total) being validly described, leaving much to be discovered, isolated, and characterized [127, 128] . the fungal kingdom is therefore underexplored with only a small percentage of total species already surveyed regarding their capacity to mycosynthesize mnps. produced mnps can have a very diverse range of characteristics and biological activities which are dependent on the formation process and the enzymatic profile of each fungal species [90] . despite the well-recognized advantages of mnps as one of the best alternatives against antimicrobial-resistant strains of mycobacteria and other taxa, several challenges and opportunities are ahead of us. given that the effects of nps result from a combination of multiple, synergistic mechanisms, the potential development of resistance against them is more arduous and less likely [124] . one should note, however, that nps are unlikely to offer a full, definitive solution, and their misuse should be avoided, as it can lead to further issues. a recent report pointed to a case of an agnps and agno 3 resistant mutant strain of m. smegmatis, developed after one single exposure and associated with increased mic for inh [129] . this unexpected case seems to be a rare event but further highlights our need to study and understand mnps. the focus of such future studies should be on testing new strains, discovering new nps, and clarifying their synthesis and mode of action as antimicrobial agents. lines for potential novel discoveries on mycogenic mnps include the study of endophytic and extremophilic strains. while the former has increased its relevance within the last years (table 2) , the latter is still restricted to a very small number of studies and is focused on other applications rather than their use as antimicrobial agents [130] . the application of new approaches such as synthesis optimization via statistical methods (such as central composite design and response surface methodology) has been proposed in a few studies and showed some promise but remains mostly unexplored [98, 101] . such approaches are expected to significantly reduce the number of different lab tests required and lead to a quicker optimization of mnp production, thus warranting a closer look. like with any other drug, microorganisms might develop resistance to mnps [40, 131] , so it is essential to thoroughly investigate all aspects related to their application. this will allow us to understand and manipulate all caveats regarding their synthesis and antimicrobial mode of action, and standardize synthesis methodologies to attain best scale-up yields. furthermore, as mentioned by tăbăran et al. [7] in relation to agnps, there are a few other therapeutic obstacles to overcome: "poor delivery, variable intramacrophagic antimycobacterial efficiency, and residual toxicity". the same applies to all other mnps effective against mycobacteria. investing in exploring the capacity of new fungal species to mycosynthesize mnps is a potential source of therapeutic alternatives. this requires the investment in isolation and bioprospection of uncommon and unexplored or under-explored environments. the great resource of new fungal species to be discovered might bring to light species with even more effective and better capabilities. there is much work to be done and much to be explored, but the prospects of mycogenic mnps are very promising. mycobacterioses are an increasing public health threat and it is imperative to develop new and better solutions taking into consideration all options to control them. the scenario is particularly bleak for tb. innumerous actions and campaigns over the recent decades have contributed to a tendency to control the infection, but tb is still neglected by many sectors. worrying recent estimates [132] ) predict that covid-19 containment measures will exact a heavy toll on health services and therefore an increase on infections such as mycobacteriosis and tb cases. mnps constitute a viable option to aid us to face this threat. this is supported by the many studies done on the different mnps synthesis processes and their vast array of applications. furthermore, mycogenic processes of mnps production, namely those relying on the use of filamentous fungi, are particularly promising. among its many advantages, the use of this production method is simple, quick, low-cost, and eco-friendly. this nanotechnology could help in killing mycobacteria, lowering drug doses and therapy periods, which in turn would help control infections. despite their benefits, mycogenic mnps remain an underexplored weapon to fight tb and other mycobacterial infections. furthermore, mycobacteria and mtb in particular have a complex pathogenesis that is not yet fully understood. considering that, according to sarkar et al. 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distributed under the terms and conditions of the creative commons attribution (cc by) license key: cord-278654-dxx6z2fj authors: wysocki, jan; batlle, daniel title: reduced plasma ace2 activity in dialysis patients: another piece in the conundrum of factors involved in hypertension and cardiovascular morbidity? date: 2013-06-19 journal: nephrology dialysis transplantation doi: 10.1093/ndt/gft240 sha: doc_id: 278654 cord_uid: dxx6z2fj the reduction in plasma ace2 activity reported in esrd patients treated by dialysis, particularly in female subjects, could limit ang ii degradation leading to increased levels of this peptide, which could contribute to the high prevalence of hypertension and cardiovascular morbidity that afflicts the dialysis population predialysis patients with ckd or renal transplant patients. when compared with historic samples from healthy subjects, however, all ckd groups examined, i.e. predialysis, transplant patients and even subjects on dialysis, seemed to have increased levels of plasma ace2 activity. statistical comparisons with healthy controls, however, could not be done because samples from healthy individuals were not assayed concurrently with those in the present study. what the study shows, in our opinion, is that while plasma ace2 activity tends to increase in ckd patients, perhaps as a compensatory mechanism to attenuate ang ii overactivity, at the time that esrd is reached and dialysis initiated a relative deficiency in plasma ace2 activity ensues. what is then the significance of reduced plasma ace2 activity in dialysis patients? as ace2 is mainly involved with the degradation of ang ii, one could readily speculate that the levels of this peptide could be augmented thereby predisposing to hypertension and other cardiovascular morbidity. as the levels of ang ii or ang (1-7) were not measured in this study, one can only consider this as a predictable consequence of ace2 deficiency that, however, still needs to be demonstrated. one also wonders about the significance of plasma ace2 activity since ace2 is mainly a tissue enzyme and its levels in the circulation, unlike the levels of ace, are relatively low. initial attempts to measure ace2 directly in plasma from healthy individuals were unsuccessful [17, 18] . moreover, circulating ace2 enzymatic activity has also been shown to be low or even undetectable in animals under physiological conditions [19] [20] [21] [22] . interestingly, in pathological states in humans, such as ischemic heart disease [23] , heart failure [24] and diabetes accompanied by vascular complications [25] as well as in rodent models of diabetes [19, 26] circulating ace2 activity is augmented. other studies in patients with connective tissue diseases, by contrast, have reported antibodies against plasma ace2 that reduce enzymatic activity [27] . the intriguing observation that human plasma itself may inhibit ace2 enzymatic activity was made based on incubation of purified recombinant ace2 with human plasma [18] . these findings suggested the presence of a small molecular endogenous inhibitor of ace2 in human plasma. consistent with this, roberts et al. now show that in a small subset of patients from each ckd subgroup, ace2 activity in unprocessed plasma was markedly lower than in plasma samples that had undergone the extraction process to remove the endogenous inhibitor of ace2 [16] . one wonders whether the process of hemodialysis itself could alter the levels of the ace2 inhibitor in plasma owing to its small molecular size. studies before and after the dialysis procedure could be informative in this regard. in the study by roberts et al. [16] , samples from patients on hemodialysis were collected prior to commencing dialysis, and on the middle dialysis day of the week. removal of the inhibitor during the dialysis procedure, however, could only increase plasma ace2 activity which is the opposite of what was observed in dialysis patients. the results of this study can therefore be interpreted to signify that the extraction of the endogenous inhibitor by dialysis is not a cause of reduced plasma ace2 activity. a possibility that the small-molecular inhibitor of ace2 might form a complex with ace2 protein thereby evading extraction during dialysis needs to be considered. if the plasma ace2 inhibitor indeed does not play a role, the question that remains is what causes the observed reduction in plasma ace2 activity in patients with esrd undergoing dialysis. the source of circulating ace2 in healthy individuals and ckd patients is not clear but release from the kidneys is a possibility. the levels of ace2 activity have been found to be 10-to 30-fold higher in mouse kidney cortex than in the heart [22] and urinary ace2 activity is about 10-fold higher in urine than in plasma [28] . the mechanism of how ace2 reaches the circulation and is then released into plasma is not well understood and requires further examination. it has been proposed that soluble ace2, which lacks its cytosolic and transmembrane domains, arises from proteolytic 'shedding' of the membrane-bound enzyme [15] . it is, nevertheless, conceivable that the full-length, membrane-bound ace2 can also be released into plasma, especially in disease states associated with tissue damage, such as myocardial infarction. in cell culture experiments, shedding of soluble ace2 is stimulated by a disintegrin and metalloproteinase, adam17, [15] and inhibited upon interaction of ace2 with calmodulin [29] . unlike ace, which is an endothelial enzyme, ace2 is normally not expressed or only minimally expressed in the endothelial layer [30] . it is possible, however, that under pathologic conditions, there may be an aberrant neoexpression of ace2 in endothelial cells [31] . this abnormally expressed endothelial protein could be shed into the circulation and could be the source of increased plasma ace2 activity in certain conditions such as myocardial infarction, kidney disease or diabetes. there have been no studies, to our knowledge, that examined plasma ace2 and the possible pathways such as adam17 or calmodulin that might be involved in modulating the release of this enzyme into the circulation. as the ace2 gene is located on chromosome x, possible differences in plasma ace2 activity between the sexes were examined by roberts et al. [16] in a multivariate analysis for males and females separately. the predictors of plasma ace2 activity in patients undergoing dialysis appeared to be different in both sexes. while in males plasma ace2 activity was strongly associated with bnp, which is increased in left ventricular hypertrophy and systolic dysfunction, female patients undergoing hemodialysis showed significant associations with diabetes and postdialysis systolic blood pressure. whether these associations have pathogenic or therapeutic implications awaits further examination. moreover, the authors found that female hemodialysis patients compared with male counterparts had lower plasma ace2 activity. analogous trend of lower plasma ace2 activity in the female group was observed for kidney transplant patients, which is similar to the recent findings of soler et al. [23] who found plasma ace2 activity significantly lower in female transplant patients when compared with males. in summary, the article by roberts et al. suggests that, in patients with ckd, plasma ace2 activity is increased whereas in patients with esrd undergoing dialysis, by contrast, plasma ace2 activity is reduced when compared with predialysis ckd patients. whether ace2 in plasma is indeed altered in ckd patients needs to be confirmed in further studies that include contemporary measurements from healthy control subjects. moreover, a longitudinal follow-up of a ckd cohort would be ideal to monitor ace2 activity as renal function declines over time. several other questions remain unanswered, such as the mechanism driving ace2 into circulation in disease states. regardless of the mechanism, the reduction in plasma ace2 activity reported in esrd patients treated by dialysis, particularly in female subjects, could limit ang ii degradation leading to increased levels of this peptide 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insights into the endogenous counter-regulatory pathway of the renin-angiotensin-aldosterone system circulating ace2 activity is increased in patients with type 1 diabetes and vascular complications ace2 deficiency modifies renoprotection afforded by ace inhibition in experimental diabetes autoantibodies to angiotensin-converting enzyme 2 in patients with connective tissue diseases urinary excretion of ace2-a biomarker of diabetic kidney disease? calmodulin interacts with angiotensin-converting enzyme-2 (ace2) and inhibits shedding of its ectodomain glomerular localization and expression of angiotensin-converting enzyme 2 and angiotensin-converting enzyme: implications for albuminuria in diabetes renal ace2 expression in human kidney disease prevalence, treatment, and control of hypertension in chronic hemodialysis patients in the united states baseline characteristics of patients with chronic kidney disease stage 3 and stage 4 in spain: the merena observational cohort study chronic kidney disease and the risks of death, cardiovascular events, and hospitalization key: cord-278513-ajfpghze authors: boyle, john t.; celano, paul; koldovský, otakar title: demonstration of a difference in expression of maximal lactase and sucrase activity along the villus in the adult rat jejunum date: 1980-09-30 journal: gastroenterology doi: 10.1016/0016-5085(80)90375-3 sha: doc_id: 278513 cord_uid: ajfpghze abstract lactase and sucrase are two disaccharidases that differ not only in their substrate specificity and developmental patterns, but also in their resistance to mucosal insult. in this experiment, we tested the hypothesis that there might be a dichotomy in expression of enzyme activity along the jejunal villuscrypt unit. sectioning of the villus-crypt unit in a cryostat enabled direct comparison of the distribution of lactase and sucrase enzyme activities in the adult rat. there is a stepwise increase in mean lactase/sucrase ratio going from crypt to villus. the data indicate that unlike sucrase activity, which is expressed maximally in enterocytes along the entire villus, maximal lactase activity is not attained until midvillus. the delay in expression of maximal lactase activity might help to explain the vulnerability of this enzyme to acute mucosal insult such as occurs in viral gastroenteritis. lactase and sucrase are two disaccharidases that differ not only in their substrate specificity and developmental patterns, but also in their resistance to mucosai insult. in this experiment, we tested the hypothesis that there might be a dichotomy in expression of enzyme activity along the jejunal villuscrypt unit. sectioning of the villus-crypt unit in a cryostat enabled direct comparison of the distribution of lactase and sucrase enzyme activities in the adult rat. there is a stepwise increase in mean lactase/sucrase ratio going from crypt to villus. the data indicate that unlike sucrase activity, which is expressed maximally in enterocytes along the entire villus, maximal lactase activity is not attained until midvillus. the delay in expression of maximal lactase activity might help to explain the vulnerability of this enzyme to ncute mucosal insult such as occurs in viral gastroenteritis. since the work of leblond and stevens,' it has been recognized that the enterocytes mature both morphologically and biochemically while migrating from the crypts to become digestive-absorptive cells of the villus. using various techniques to isolate crypt from villus cells, several different laboratories have shown in the rat that activity of enzymes asso-ciated with dna synthesis decrease,*.3 activity of lysosomal enzymes remain unchanged,z.4.6 and activity of microvillus enzymes such as alkaline phosphatase and disaccharidases increase'-' as cells migrate along the heights of the villus. early in this century, finkelstein and meyer recognized that infants with acute gastroenteritis could not tolerate "complex sugars."" subsequent studies have shown that this is usually a manifestation of transient lactose intolerance,'*'* whereas an ability to absorb sucrose is usually preserved.13-'5 thus, these two disaccharidases differ not only in their substrate specificity and developmental patterns,18"' but also in their resistance to mucosal insult. since the absolute activity of lactase is low compared to sucrase both in the human" and rat," a comparable loss of both enzymes after mucosal injury may reduce lactase activity below a critical threshold to allow for physiologic hydrolysis of dietary lactose. however, the decrease in the ratio of lactase to suerase activity in small bowel biopsies of patients who are lactose intolerant after acute mucosal injury indicates a higher vulnerability of lactase compared to sucrase.13-'5 by studying incorporation and turnover of radiolabeled amino acids, james et al. have shown that microvillus proteins do not have a uniform rate of turnover.20 alpers showed that the largest molecular weight proteins (including the disaccharidases) have the fastest rate of turnover.2l therefore, both synthesis and degradation of disaccharidases are taking place along the entire length of the villus crypt! differences in location where synthesis begins, ot differences in the rate of turnover of lactase and suerase might lead to a difference in enzyme distribution along the villus-crypt unit. differences in localization of enzyme activity in turn might help explain the decrease in the ratio of lactase to sucrase (0), and acid &alactosidase (a) along the villus-crypt unit. abcissa depicts "idealized villus-crypt unit" as explained in the methods section, with 100% representing the top-most part of the villus and 0% the bottom-most part of the crypt. histologic examination of sections revealed villi to make up 65%; mixed villus crypt, 20%; and crypt, 15% of the total villus-crypt height. because of very low protein in homogenates from apical 10% of villus crypt, the amount of absorbance measured by spectrophotometer was very low both for lactase and sucrase, and. therefore, enzyme activity was not considered accurate for presentation. short vertical lines denote 1 sem. absence of vertical line indicates that value of sem is smaller than the symbols used. all figures in the text represent data from eight rats; each point on graph represents mean data from 6 to 8 homogenates. activity in small bowel biopsies after intestinal mucosal insult. although different investigators have described an apical localization of one or the other enzyme along the villus-crypt unit, no one to date has systematically compared the localization of lactase and sucrase activities on the same villus-crypt unit. in the present study, we compare localization of lactase and sucrase activity on the same villus-crypt unit after sequential sectioning in a cryostat by using the technique of van genderen and engel" as modified by nordstrom et al.' the data indicate that, unlike sucrase activity, which is maximally expressed in enterocytes along the entire villus, maximal lactase activity is not attained until midvillus. male rats of charles river strain cd (wilmington, mass.) were shipped at 2 mo old and were kept 4-6 wk in our animal house before being used in experiments. animals were fed a standard rat chow (purina co. no. 5001) ad libitum, and weighed between 300 and 350 g at time of gastroenterology vol. 79, no. 3 study. fed rats were killed by decapitation at 9:oo am, and a 5 x 5-mm segment of jejunum was sectioned within a cryostat at -18% as previously described.' horizontal sections were cut 10 pm thick (no. 5 setting on iec microtome, needham hts., mass.). at various depths into the villus-crypt unit, a section was attached to the microscope slide for immediate inspection of histology under a phase-contrast microscope. the tissue blocks were sectioned through the submucosa to the proximal muscular layer. commencing with counting of sections, every six consecutive sections were combined and homogenized in 0.5 cm3 distilled water by vortex shaking and sonification x 30 set (sonifier cell disrupter, model v185, heat systems-ultrasonics, inc., plainview, n.j.). assays of lactase and sucrase activities were performed on each homogenate according to the method of dahlqvist.23 the lactase assay mixture contained p-chloromercuriobenzoate (pcmb) (aldrich chemical co., milwaukee, wis.) in order to inhibit any residual lysosomal acid /3-galactosidase activity." all enzyme determinations were made under conditions of linear activity with time and concentration of the enzyme. protein was determined according to the method of lowry et a1.25 all chemicals used were of reagent grade. three possible problems associated with the lactase assay were investigated (data not shown): (a) to test for the presence of an inhibitor of the glucose oxidase reaction, homogenates obtained from different heights of the villuscrypt unit were boiled and the same protein concentration as used in the enzyme assays were added to the glucose standards.zb the resulting curves showed no significant inhibition. (b) the possibility of an inhibitor of enzyme activity in lower sections of the villus crypt was studied by combining homogenates of equal protein concentration from apical villus and lower villus-mixed crypt sections. the resulting activity for both lactase and sucrase approximated the arithmetic mean activity calculated to result from such a mixing. (c) the dependence of lactase activity on ph was determined in homogenates from apical, mid-, and lower villus-mixed villus-crypt areas of the villuscrypt unit. the ph optimum for lactase activity at all heights was between 5.0 and 6.0. in the presence of pcmb, all activity at ph 3.5 was abolished. since the ph optimum of acid /3-galactosidase is 3.5, this verifies that in homogenates of cryostat sections, pcmb totally inhibits the acid /%galactosidase activity as has also been shown in whole intestinal homogenates, and partially purified fractions of this lysosomal enzyme.z4*2'~28 since there was some variation in the number of sections obtained from different animals, the activities of various enzymes in serial homogenates were related in an "idealized villus-crypt unit."%' this maneuver allowed data from a number of animals to be easily compared. the percent distance each homogenate represented of the total villus-crypt unit was determined in any given tissue block. thus, enzyme activity in the sixth of 16 homogenates was considered to represent enzyme activity at a point between 35% and 40% of the distance between tip and base of an "idealized villus-crypt unit." table 1 . the enzyme activity of each homogenate was calculated both as specific activity (micromoles of substrate hydrolyzed per hour per milligram protein) and as total activity (micromoles of substrate hydrolyzed per hour per homogenate). since both lactase and sucrase activities were performed on the same homogenates, the lactase/sucrase ratio is independent of how the individual activities are expressed. however, to allow for statistical comparison between individual lactase and sucrase activities at any point along the villus-crypt unit, two alternative modes of expression of data were utilized: (a) the highest specific activity of each enzyme along the villus-crypt unit in any given rat was set at 100% and all other activities on the same unit expressed as a percent of that highest activity. (b) the total activity of each tissue block was determined by summation of total activities of consecutive homogenates. the total activity of each enzyme in each homogenate was then expressed as a percent of the total activity of the tissue block. the data from each of eight rats were plotted along the idealized villus-crypt unit as explained above. average values for each 5% of distance were calculated. when comparing lactase to sucrase activity at any given height of the villus-crypt, student's t-test was used.2q one-way analysis of variance30 was used to determine if there was significant variation of mean lactose/sucrose (l/s) ratios at different heights of the villus crypt. figure 1 shows the distribution of specific lactase, sucrase, and acid /&galactosidase activity along the villus-crypt unit. the general pattern of distribution of activity agrees with previous reports.'-' the mean l/s ratios at different heights of the villus crypt are plotted in figure 2 . since both enzyme assays were performed on the same homogenate, the l/s ratio is independent of how enzyme activity is expressed. the results show that there is a definite gradient of increasing l/s ratio in going from crypt to apical villus. using one-way analysis of variance, the ratio in lower villus is significantly less than in apical and midvillus ( table 1 ). the reason for this increase in l/s ratio can be seen if the specific activity of each enzyme is expressed as a percent of the maximal specific activity along a particular villuscrypt unit (figure 3 ). sucrase reaches maximal activity in enterocytes along the upper 70%-75% of the villus-crypt height, whereas lactase does not peak until the top 45%-50%. if the total activity of each enzyme in each homogenate is expressed as a percent of the total activity of the tissue block, the lag in expression of maximal lactase activity is also seen (data not shown). total activity of both disaccharidases decreases sharply in the apical portions of the villus-crypt unit because of small amounts of protein in apical homogenates. the net result of the different patterns of distribution is that 63% + 3% (mean +-sem) of total lactase activity along the villus-crypt unit is present on the top 50% of the unit as compared with 51% + 3% of sucrase activity (p < 0.02) this is the first report that directly compares distribution of lactase and sucrase activities along the crypt-villus unit of the adult rat. the technique x, y x = p < 0.05; y = p < 0.01. for statistical purposes, individual data for each 10% of height of the villus crypt were pooled. one-way analysis of variance confirmed that population means differ substantially, f = 18.9. least significant difference (lsd) was used to compare individual means. figure 3 . relative activity expressed as mean percent maximal specific activity of sucrase (0) and lactase (0) along the villus-crypt unit. the highest specific activity in each tissue block was set at 100% and activities in all other homogenates expressed as a percent of that highest activity. letters denote level of statistical significance between lactase and sucrase activities at any point along the villus-crypt unit. (a. p < 0.05; b. p < 0.02; c. p c: 0.01; d. p < 0.001.) absence of letter indicates no significant differences between maximal activities at a given height. of cryostat sectioning of frozen intestine was chosen because it provides precise sequential separation of cells along the villus-crypt unit after minimal manipulation of bowel. the other accepted method of cell separation is the weiser "washing" technique.3 while this is an excellent method for obtaining isolated enterocytes from apical villus, lower villus, and crypt, we were concerned with the specificity of "washing" cells sequentially down the villus in order to determine a true gradient of enzyme activity. in addition, the method does not control for the possibility of differential binding of the two enzymes onto the microvillus. selective solubilization of lactase in early washings from cells still adherent to the villus-crypt unit may result in erroneously low levels in lower portions of the villus. in our present study, the general pattern of distribution of both lactase and sucrase along the villus crypt agrees with previous reports,z-7 i.e., localization of activity to the villi and absence of activity in the crypts. however, by directly comparing enzyme activity in the same homogenate at each height of the villus crypt, we found that, unlike sucrase, lactase fails to achieve maximal activity until midvillus. this observation is based on the stepwise increase in mean l/s ratio going from crypt to midvillus. since both lactase and sucrase enzyme assays were performed on the same homogenate, the l/s ratio is independent of how enzyme activity is expressed. the more apical localization of lactase activity compared to sucrase activity on the crypt-villus unit may help to explain the vulnerability of this enzyme to acute mucosal injury (e.g., acute gastroenteritis). histologic studies in acute viral gastroenteritis have shown blunting of villus height and disorganization of surface epithelial cells.3*~32 in the event of apical destruction of villus cells carrying lactase activity, the remaining activity in cells in the mid to lower levels of the villus may be below critical threshold to allow for physiologic hydrolysis of lactose. it is important to remember that total jejunal lactase activity is between one-fifth (unpublished from our laboratory) and one-tenth" that of sucrase activity in the adult rat. the more even distribution of sucrase along the crypt-villus unit would then explain the usual normal ability to absorb sucrose in acute gastroenteritis. recent data suggest that invasion and damage of epithelial cells by the virus itself may not be the only factor in the pathogenesis of diarrhea in this disease. study of transmissible gastroenteritis in piglets (corona virus) has suggested that intestinal epithelial cell migration rates increase in response to viral invasion.33.34 while this leads to rapid desquamation of infected cells, the villi become populated by relatively immature cryptlike cells. based on results of the present experiment, lactase activity, which is more dependent on cell maturity than sucrase, would be primarily affected by reparative events occurring after infection. nordstrom et a1.35 have described the distribution of disaccharidase activity along the crypt-villus unit in 1 human patient using the same technique as in our report. difficulties in mounting and slicing human tissue restricted statistical comparison between a number of patients. although it is not stated that the activities of all enzymes were assayed on the same villus-crypt unit, the authors report a more apical distribution of jejunal lactase activity when compared to sucrase and maltase. this observation lends further clinical credence to the significance of the present studies in the rat. further studies are needed to determine the mechanism responsible for the differences in distribution of lactase and sucrase activities. differences in location where synthesis begins, or differences in the rate turnover of lactase and sucrase might lead to a difference in enzyme distribution along the villuscrypt unit. in view of the similarities of the lactase and sucrase distribution pattern between rat and human, the rat would be a suitable model for these studies. studies of small intestine. iii. infantile diarrhea associated with intolerance to disaccharides carbohydrate intolerance in infants with diarrhea jejunal disaccharidase activities in acute diarrhea and convalescence (abstr) gastroenterology 54:1244 evaluation of a sucrose/electrolyte solution for oral rehydration of acute infantile diarrhea prospective comparison of indirect methods for detecting lactase deficiency effect of cortisone on the developmental pattern of the neutral and the acid fi-galactosidase of the small intestine in the rat the constant renewal of the intestinal epithelium of the albino rat intestinal enzymes: indicators of proliferation and differentiation in the jejunum intestinal epithelial cell surface membrane glycoprotein synthesis dahlqvist a: localization of /?-palactosidases and acid phosphatase in the small intestine wall. comparison of adult and suckling rat characteristics and postnatal development of acid lipase activity of the rat small intestine protein synthesis in small intestine: localization and correlation with dna synthesis and sucrase activity quantitative determination of enzymes in different parts of the villi and crypts of rat small intestine the digestive function of the epithelium of the small intestine. ii. localization of disaccharide hydrolysis in the isolated brush border portion of intestinal epithelial cells zur technik und indikation der ernahrung mit eiweissmilch acquired milk intolerance in adult caused by lactose malabsorption due to a selective deficiency of intestinal lactase activity koldovsky 0: cell migration and cortisone induction of sucrase activity in jejunum and ileum isolated intestinal lactase deficiency in the adult intestinal disaccharidase activities in adult and suckling rats the turnover of disaccharides and brush border proteins in rat intestine the relation of size to the relative rates of degradation of intestinal brush border proteins on the distribution of some enzymes in the duodenum and ileum of the rat method for assay of intestinal disaccharidases a method for the separate assay of "neutral" and "acid" p-galactosidase in homogenates of rat small intestine mucosa protein measurement with folin phenol reagent use of the glucose oxidase method for assay of disaccharidase activities in the small intestine-a limitation rat small intestinal p-galactosidases separation and isolation of rat and human intestinal /3-galactosidases the principles and practice of statistics in biological research acute infectious nonbacterial gastroenteritis: intestinal histopathology recent advances in viral gastroenteritis transmissible gastroenteritis of swine: virus-intestinal cell interactions transmissible gastroenteritis: sodium transport and the intestinal epithelium during the course of viral enteritis quantitative distribution of some enzymes along villi and crypts of human small intestine key: cord-320693-de1lmzl1 authors: hu, han; guo, nan; chen, shuhua; guo, xiaozhen; liu, xiaoli; ye, shiyi; chai, qingqing; wang, yang; liu, binlei; he, qigai title: antiviral activity of piscidin 1 against pseudorabies virus both in vitro and in vivo date: 2019-07-31 journal: virol j doi: 10.1186/s12985-019-1199-4 sha: doc_id: 320693 cord_uid: de1lmzl1 background: swine-origin virus infection spreading widely could cause significant economic loss to porcine industry. novel antiviral agents need to be developed to control this situation. methods: in this study, we evaluated the activities of five broad-spectrum antimicrobial peptides (amps) against several important swine-origin pathogenic viruses by tcid(50) assay. plaque reduction assay and cell apoptosis assay were also used to test the activity of the peptides. protection effect of piscidin against pseudorabies virus (prv) was also examined in mouse model. results: piscidin (piscidin 1), caerin (caerin 1.1) and maculatin (maculatin 1.1) could inhibit prv by direct interaction with the virus particles in a dose-dependent manner and they could also protect the cells from prv-induced apoptosis. among the peptides tested, piscidin showed the strongest activity against prv. moreover, in vivo assay showed that piscidin can reduce the mortality of mice infected with prv. conclusion: in vitro and in vivo experiments indicate that piscidin has antiviral activity against prv. swine-origin virus infection is one bottleneck for the development of the porcine industry worldwide. the pathogenic viruses isolated from pigs including pseudorabies virus (prv), porcine reproductive and respiratory syndrome virus (prrsv), porcine epidemic diarrhea virus (pedv), transmissible gastroenteritis virus (tgev), and rotavirus (rv) are commonly observed in china. the viral infection is also responsible for the secondary infection by bacteria which has greatly increased the application of antibiotics [1, 2] . in the past decades, the efforts to alleviate pig viral diseases have focused on the development of vaccines to enhance the adaptive immunity of the hosts [3, 4] . however, some of the evolving viruses could escape from the host immunity through different kinds of strategies. several viral diseases have broken out in recent years among pig herds, such as the reemergence of swine-origin influenza in 2009 [5] , ped in late 2010 [6] and pseudorabies in 2012 [7] . thus, there is an urgent need to develop novel potential agents to kill these viruses or block their infection. amps are common host defense molecules in nearly all forms of life. ever since their discovery, amps have gained worldwide attention as important alternatives in the field of disease prevention and immune modulation [8, 9] . previous studies mostly focused on the protection effect of amps against bacterial and fungal infection [10] . later on, amps were also reported to be effective against viral infection [11] . it has been reported that some alpha-helical peptides can act as virucidal agents. for example, caerins and maculatins isolated from amphibian skin could completely inhibit human immunodeficiency virus type 1 (hiv-1) infection after virus is exposed to peptides within minutes [12] . piscidins, discovered in the mast cells of fish, could reduce the infectivity of several important fish-origin viruses [13] . indolicidin, a natural 13-amino acid antimicrobial peptide isolated from bovine neutrophils, could directly kill hiv-1 [14] . bovine lactoferricin derived from bovine lactoferrin has been reported to exert antiviral activity to fight against human cytomegalovirus (hcmv), herpes simplex virus type 1 (hsv-1), hsv-2, and adenovirus [15] . other antimicrobial agents, such as human defensins which is a group of beta-sheet peptides, can inhibit enveloped viruses such as hsv-1 and hsv-2, hiv-1, vesicular stomatitis virus (vsv), influenza virus, and hcmv by directly inactivating viruses [16] . therefore, amps might be promising agents against viral infections. prv, a large enveloped dna virus, is a swine neurotropic herpesvirus [17] . although the pigs are the natural reservoir for the virus, most mammals and some avian species are also susceptible to prv. prv infected animals may die from central nervous system disorders [18] . prv infection poses a severe threat to pig industry and either attenuated live or inactivated vaccines are usually used to control the disease [19] . although vaccination can suppress development of the disease, vaccines cannot eliminate virus infection. mutant isolates emerged and caused pseudorabies outbreak in 2012 [7] . thus, novel antiviral agents should be developed as a complementary to vaccination. in one of our recently published papers, we described the antiviral activity of caerin against porcine epidemic diarrhea virus (pedv) in vitro [20] . in this study, we investigated the activity of five amps including piscidin, caerin, maculatin, lactoferricin b, and indolicidin against several porcine-origin viruses. more inhibitory activity of piscidin, caerin, and maculatin against prv was also explored. the in vivo protection effect of piscidin against prv infection was further investigated. chen et al found that piscidin has the anti-inflammatory and anti-nociceptive properties in inflammatory animal models [21] . kumar et al reported the obvious anti-endotoxin and anti-bacteria properties of piscidin-1 analogues both in vitro and in vivo [22] . the peptides (table 1 ) used in this study were synthesized on an automated solid-phase peptide synthesizer by neweast biosiences inc. (wuhan, china) [23] . the crude peptides were purified via a reverse-phase highpressure liquid chromatography (rp-hplc) using a c 18 column (waters xbridge). the elution was conducted using a water-acetonitrile linear gradient (0-80% of acetonitrile) containing 0.1% (v/v) trifluoroacetic aicd (tfa). finally, the purity and accurate masses of the product peptides were determined using hplc and mass spectrometry, respectively. the prv strains of ea, hnxx, 152, and tgev wh-1 were propagated in pk-15 cells based on the method reported in previous studies [24] . rv tm-a was propagated in rhesus monkey kidney cell line (ma104) [25] . prrsv ya was cultured in marc-145 cells [26] . pedv strain ch/ynkm-8/ 2013 was cultured in vero cells as described before [27] . the virus suspension was stored at − 80°c until used. in our initial topical screening assays, the viruses were pre-incubated with peptides (50 μg/ml) for 1 h at 37°c before they were added to the target cells. peptide-free controls (virus plus cell culture medium only) were incubated in parallel. after incubation, the tcid 50 of peptidetreated viruses and peptide-free viruses was measured. residual virus was calculated according to the following formula, residual infectivity = b/a × 100% ("a" represent tcid50 of residual virus non-treated by the amps (control), "b" represent tcid50 of residual virus after treated by amps). a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (mtt) cell proliferation assay was used to assess cell viability as described previously [28] . briefly, pk-15 cells were added to 96-well tissue-culture plates (coster, usa) and incubated overnight at 37°c. serial two fold dilutions of amps ranging from 200 to 3.12 μg/ml were added into the plate. the cells were incubated with amps at 37°c for 48 h, and the morphology of the cells was evaluated under light microscope. then, the cells were further incubated with mtt solution for 4 h and the cell pellets were collected for measurement of absorbance at 490 nm by an elisa reader. the antiviral activity was evaluated by plaque reduction assay [29] at different infection stages: pre-infection and post-infection, as well as direct inactivation of the viruses. briefly, the direct effect of peptides on virus per se was analyzed by the following procedures. monolayer of to analyze the post-infection effect of the peptides on virus growth, cells were infected with the same amount of virus mentioned above at 37°c for 1 h. subsequently, the cells were washed 3 times with dmem and treated by the peptides at different concentrations for 1 h at 37°c. the peptides were removed from the cell culture and replaced with the overlaid medium. the resulting pfu titer was determined as described above. to understand the pre-infection effect of the peptide on virus, the cells in 12-well tissue culture plates were treated with peptides at serial concentrations at 37°c for 1 h. then, cells were washed with dmem for 3 times, followed by infection with viruses. the cells were covered with the overlaid medium for plaque assays. cell apoptosis was analyzed with annexin v-fitc kit (nanjing keygen biotech. co., ltd). briefly, fitc-conjugated annexin v (50 μl/well) and propidium iodide (pi, 50 μl/well) were added to the cells infected by amptreated viruses. then, the obtained mixture was incubated at room temperature for 15 min in the dark prior to fluorescence observation. cell apoptosis was determined on basis of the observation soon after initiating apoptosis. cells translocated the membrane phosphatidylserine (ps) from the inner surface of the plasma membrane to the cell surface. thereafter, ps can be easily detected by staining with a fluorescent conjugate of annexin v (green), a protein that has a high affinity to ps. cellular late apoptosis was determined by cell staining with pi (red). the results were analyzed by fluorescence microscope (nikon, japan) at 36 hpi. in vivo prv challenge assay the 6 to 8 week-old specific-pathogen-free balb/c mice were purchased from the experimental animal center of zhongnan hospital of wuhan university (china) and randomly divided into six groups consisting of 10 mice each. individuals in each group of mice were anesthetized with 1-3% isoflurane gas and challenged by the intra-footpad injection with 50 μl of dmem containing 5 × 10 3 tcid 50 of prv-ea in the presence or absence of 10, 5, 1, 0.2 μg/ml piscidin. after 14 days, the surviving mice were challenged with 5 × 10 3 tcid 50 of prv again. mice viability and behaviors were monitored on a daily basis. in the first 2 days after the challenge, the mice commonly did not exhibit severe symptoms. however, mice gradually showed neurological symptoms in the subsequent days during the monitoring period and the post-challenged mice were monitored since day 3 post prv infection once every 6-8 h for 8 days to obtain the survival information of the mice. the level of prv infection symptoms was scored for every mouse by the following system: 0 = posture normal, absence of neurological symptoms, 1 = mild neurological symptoms: excitation, unrest, occasional itching, and foot swollen; 2 = severe neurological symptoms: ataxia, severe pruritus, and self-mutilation, biting and bleeding of the footpad. mice were euthanized in the chamber with co2 gradually filled when the score reached 2. on day 6, three mice from control group and noncontrol groups were euthanized and brain tissues were collected and transferred to 4% paraformaldehyde. the tissues were dehydrated in ascending grades of ethyl alcohol i.e. 70, 90 and 100% ethanol. afterwards, the tissues were cleared with xylene. slides were stained with haematoxylin and eosin (h&e) stain and analyzed through a light microscope. all of the animal experimental protocols were approved by the ethics committee of huazhong agricultural university according to hubei province laboratory animal management regulations (hzaumo2015-0015). during the experiments, mice were offered ad libitum access to water and food in a controlled environment of a 12 h light/dark cycle. all efforts have been made to reduce suffering of animals. the antiviral effects of the peptides (maculatin, caerin, piscidin, lactoferricin b, indolicidin) were investigated in vitro against several viral pathogens that severely threaten the porcine industry. four enveloped viruses were used in this assay including the prv ea strain, pedv ynkm strain, tgev wh-1 strain, and prrsv ya isolate, as well as one non-enveloped rv tm-a strain. the peptides exhibited different inhibitory activities against these viruses (fig. 1) . the relative potency of the peptides against prv was: piscidin≈caerin>ma-cualtin>indolicidin> lactoferricin b. piscidin and caerin showed strong virucidal activity with the residual infectivity being around 2.3% while indolicidin and lactoferricin b exhibited mild antiviral activity. in descending order of potency, the peptides against pedv ranked as follows: caerin>piscidin> maculatin>lactoferricin b > indolicidin. caerin had the most potent activity with the residual infectivity being 0.2%. the assay results indicated, that the order of potency versus prrsv was: caerin>lactoferricin b > piscidin>maculatin>indolicidin. caerin exhibited the best inhibitory activity with the residual infectivity being 41.1%, separately. the assay results of antivirus activity against tgev indicated the activity order as follows: piscidin>lactoferricin b > indolicidin>maculatin>caerin. piscidin was the most potent peptide versus tgev with the residual infectivity being 41.5%. the assay result also indicated that prrsv and tgev were less sensitive to the tested peptides, compared with other viruses (fig. 1) . when it comes to rv, the relative potency order was: piscidin>caerin>maculatin>lactoferricin b > indolicidin. piscidin displayed the most potent activity against rv with residual infectivity being 7.4%. piscidin and caerin exhibited activity against almost all the viruses with the residual infectivity being lower than 50% with exception of piscidin versus prrsv and caerin versus tgev. caerin showed the greatest inhibitory activity against pedv with the residual infectivity being 0.2%, which was the lowest value among all the viruses tested. maculatin exhibited strong activity against prv (10.1%) and mild activity against rv (43.4%). however, it showed limited activity against pedv, prrsv, and tgev. lactoferricin b and indolicidin were not as potent as other peptides to fight against viruses. lactoferricin b showed stronger inhibitory activity against tgev than against other tested viruses with residual infectivity being 54.1%, and residual infectivity of indolicidin versus prv was 34.6%. we examined the effects of amps on cell viability after incubating pk-15 cells with different concentrations of each peptide. cytotoxicity was evaluated using mtt method (fig. 2) . the non-linear regression analysis result indicated that the 50% toxic concentration (tc 50 ) of caerin, maculatin, piscidin, and indolicidin were 67.8, 76.6, 65.2, and 110.2 μg/ml, respectively. indolicidin was fig. 1 spectrum of antiviral activity of the peptides (tcid 50 assay). peptides (50 μg/ml) and viruses were incubated at 37°c for 1 h before they were added to the target cell monolayers. after incubation for 48-72 h, tcid 50 of the virus was recorded. the bars represent ± se. three separate assays were conducted (n = 3). the dashed line means 50% residual infectivity fig. 2 cytotoxic properties of the peptides. pk-15 cell monolayers were incubated with peptides. the cytotoxicity was measured by mtt assay (n = 3). the cell survival rates at different peptide concentrations were plotted and the dashed line means 50% cell survival less cytotoxic than piscidin, caerin and maculatin. lactoferricin b exhibited the weakest cytotoxic activity and it did not exhibit obvious cytotoxic activity even at maximum concentration of 200 μg/ml. to determine whether the inhibitory activity against prv by maculatin, caerin, piscidin was strain-specific or not, we tested the activity of these peptides against different prv isolates including prv-hnxx (a newly prv isolate in china in 2012) and prv-152 (modified bartha strain). we found that all the three peptides displayed inhibitory activities against all the tested strains (prv hnxx, prv 152, and prv-ea) (fig. 3a) . this finding indicated that the activity of the peptides versus prv was not strain-specific. when the concentration of the peptides increased from 50 to 100 μg/ml, the residual infectivity of prv decreased (fig. 3b) . this trend was the most obvious for maculatin with the residual infectivity decreasing from 10.11 to 0.0017%, while the groups treated with piscidin and caerin exhibited a decrease by more than 30 folds in the residual infectivity. these data indicated that these peptides inhibited the virus in a dose-dependent manner. in order to better understand the inhibitory effect of amps on the propagation of prv-ea, we examined a b fig. 3 prv inhibitory activity displayed by maculatin, piscidin and caerin (tcid 50 assay). a prv of ea, hnxx strain and 152 isolate were treated with the peptides (50 μg/ml) for 1 h before they were added to the cell monolayers. the bars represent means ± standard errors of the means of three separate experiments (n = 3). *, statistically significant difference by one-way anova with tukey post hoc test (p < 0.05), ns means not significant. b prv ea was treated with peptides (100 μg/ml) for 1 h before added to the cell monolayers. the effects of the peptides at 50 μg/ml and at 100 μg/ml against prv ea were compared whether amps directly damaged virus particles or indirectly interacted with the host cells pre-or post-infection. plaque-reduction assay was also performed to confirm the peptides' antiviral activity. the viruses were incubated with the peptides prior to infection. the result showed that all the three peptides inhibited the virus infection in a dose-dependent manner (fig. 4) . at the concentration of 25 μg/ml, pisicidin, caerin and maculatin were found to inhibit most of the prv particles. pisicidin exhibited the strongest activity and obvious inhibitory ability at concentrations above 5 μg/ml. the 50% effective concentration (ec 50 ) values of the peptides were calculated using probit analysis by ibm spss (version 21, new york, usa). the analysis revealed that ec 50 values of caerin and maculatin were 2.63 μg/ml and 1.09 μg/ml, respectively. ec 50 of piscidin was the lowest (0.23 μg/ml) among the peptides tested, which indicated that piscidin was the most potent antiviral peptide against prv in this study. subsequently, the experiments were conducted to further determine whether the peptides could function at post-(curative) or pre-infection (prophylactic) stage. the cell monolayers were treated with piscidin, caerin, and maculatin before (prophylactic) or after (curative) the virus binding stage, separately. no inhibitory effect of the three peptides on prv could be detected (the obtained data not shown). this implied that these peptides probably inhibited prv infection by directly interacting with the virus particles. the cell apoptosis assay showed that prv could induce both early and late apoptosis of pk-15 cells (fig. 5) . the late apoptosis rate of cells infected by the peptides-treated viruses decreased as the concentration of the peptide increased (fig. 5b) . the inhibition of late cellular apoptosis was obvious at the concentration of 25 μg/ml (fig. 5a) . in the control group of the in vivo assay, mice (n = 10) were injected with 50 μl of piscidin (200 μg/ml) by the intra-footpad route. all mice survived and behaved normally. prv was injected into mice with or without piscidin at various dosages (0.5, 2.5, 5, 10 μg/ml). and the surviving mice were re-challenged with prv on day 14 (fig. 6) . the mice survival rate was recorded for 28 days. protected against prv infection (fig. 6) . however, one mouse from the 2.5 μg/ml peptide-treated group and nine mice from the 0.5 μg/ml group died within 10 days. to further characterize the prevention effect of piscidin against brain damage induced by prv, the brain sections of mice from the control group, prv-infected, and co-injection group were collected respectively and subjected to pathological examination. the blood stasis was observed in the brain of mice from prv-infected group (fig. 6a) . the brain of mice from co-injection group showed no specific symptom. after 14 days, the surviving mice were re-challenged with prv at 5 × 10 3 tcid 50 . the groups co-injected with piscidin and prv failed to provide protection with the survival rates dropping to 30% at the end of the experiment and the mice in the 5 μg/ml peptide treated group all died. we previously reported the proof-of-concept usage of amps as the bactericidal agents against pathogenic bacteria isolated from pig herds [23] . the five antimicrobial peptides used in this study have been reported to inhibit the growth of various kinds of viruses including hiv, hsv-1, hsv-2, etc. [12] [13] [14] [15] [20] [21] [22] . however there has been limited information about the inhibitory activity of these peptides against the swine-origin viruses. considering this, this study evaluated the effect of these peptides against several porcine viral pathogens. three peptides (caerin, piscidin, maculatin) exhibited inhibitory activity against prv, pedv, tgev, prrsv, and rotavirus. plaque reduction assay showed that the prv infection could be inhibited in a dose-dependent manner by direct treatment of the peptides. a previous study indicated that caerin and maculatin could inhibit hiv infection without affecting t-cell viability and that the activity of caerin was more potent than that of maculatin [12] . in our research, we further tested the activity of caerin and maculatin against prv, pedv and prrsv. compared with maculatin, caerin showed better activity against most of the tested viruses except tgev (fig. 1) . the fact that caerin has a longer α-helix than maculatin, which enables caerin to disintegrate the membrane more potently, might explain the better activity of caerin. usually, the bacterial membrane and viral envelope were reported to be the main targets of the amps. for example, hiv envelope integrity was directly disrupted by caerin and maculatin [12] . however in this study, tgev and prv which both acquired their envelopes from pk-15, exhibited different levels of sensitivity to the tested peptides. in addtion to its envelope, physical characteristics of the virus such as viral size, surface area, and morphology might affect its sensitivity. hnp-1 also demonstrated a 1000-fold difference in activity against different enveloped viruses [16] . it should also be noted that the antiviral activity of the amps tested in this study is only observed at concentrations that are already somewhat cytotoxic at 48 h and could be even more so at 72 h or longer. to our surprise, piscidin, caerin, and maculatin a b fig. 6 piscidin protects mice from prv-induced death. a. processed brain sections from control, co-treated, and prv infected groups were subjected to haematoxylin and eosin (h&e). the representative h&e results were shown. b. the mice injected with piscidin or prv, co-treated with piscidin and prv were divided into different groups. surviving mice were challenged with prv on day 14 again. survival status of control and experiment groups were monitored on a daily basis for 28 days (n = 10). in the group of piscidin (10 μg/ml), 2 mice were heavily infected and died on day 19 and 20. and another 5 mice with severe neurological symptoms were euthanized for animal welfare reasons; in the group of piscidin (0 μg/ml) + prv, 2 mice were heavily infected and died on day 5. and another 7 mice with severe neurological symptoms were euthanized for animal welfare reasons; in the group of piscidin (10 μg/ml) + prv, 1 mouse was heavily infected and died on day 19. and another 6 mice with severe neurological symptoms were euthanized for animal welfare reasons; in the group of piscidin (5 μg/ml) + prv, 3 mice were heavily infected and died on day 19 and 20. and another 7 mice with severe neurological symptoms were euthanized for animal welfare reasons; in the group of piscidin (2.5 μg/ml) + prv, 1 mice were heavily infected and died on day 20. and another 6 mice with severe neurological symptoms were euthanized respectively for animal welfare reasons; in the group of piscidin (0.5 μg/ml) + prv, 3 mice were heavily infected and died on day 5 and 7. and another 6 mice with severe neurological symptoms were euthanized for animal welfare reasons; a total of 11 mice from all groups survived and were euthanized by the end of the experiment could consistently inhibit the growth of rv, a non-enveloped rna virus. among these three peptides, piscidin showed the strongest inhibitory activity. it has been reported that piscidin possessed significant antiviral activity to fight against both frog virus 3 and channel catfish virus [30] . the reduction of fv3 infectivity resulting from the application of piscidin is due to its capacity to interact with the essential lipid membrane of fv3 [13] . based on these results, it could be speculated that there might be other targets for these peptides in addition to the viral envelope, which need further exploration. lactoferricin b and indolicidin showed weak or no activity against the five tested viruses compared with caerin, maculatin, and piscidin. robinson et al reported that the ic 50 of indolicidin against hiv-1 ranged from 67 μg/ml to 100 μg/ml [31] . the weak activity of indolicidin against the tested viruses in this study was probably due to the low concentration we used (50 μg/ml). it has been reported that amps could inhibit both extracellular and intracellular viruses [32] [33] [34] . our plaque reduction assay result indicated that piscidin, caerin, and maculatin could inhibit prv by directly interacting with the virus. addition of the peptides pre-or post-infection could not help inhibit the prv infection. vancompernolle et al reported that caerin inhibited hiv infection by disrupting the virion envelope [12] . chinchar et al also reported that amphibian-origin esculentin-2p (e2p) and ranatuerin-2p (r2p) could inactivate the channel catfish virus (ccv) by directly interacting with the virions [35] . the re-emergence of pseudorabies in china since 2011 has caused a huge economic loss to the pig farms. three prv strains, i.e. ea, 152 and hnxx, were chosen for further evaluation of peptide's antiviral activity. the peptides inhibited replication of the three prv strains. this is of great importance in fighting against the mutant viruses resulting from natural selection or antibodyinduced events. on the other hand, these peptides had some cytotoxicity on pk-15 cells (fig. 2) . piscidin has been reported to have antiviral and antibacterial properties in vitro [13, 36] . however, this had not been tested in vivo. in this study, the data showed that coinjection of prv with piscidin at the concentration of above 5 μg/ml could offer protection against prv infection. even when the concentration of piscidin decreased to 2.5 μg/ml, the survival rate of mice could reach 90%. huang et al previously reported that th1-5, as an amp isolated from tilapia, could offer 80% protection against jev infection at 100 μg/ml [37] . compared with th1-5, piscidin was more effective even at low concentration. as huang et al noted, th1-5 treated mice surviving from the first jev infection remained alive after second challenge with jev at day14 [37] . however, our in vivo studies exhibited a different result. the possible reason needs further exploration. this study indicated that piscidin, maculatin and caerin could inhibit the infection of prv, prrsv, pedv, tgev and rotavirus. among the peptides examined in this study, piscidin showed the strongest antiviral activity against prv both in vitro and in vivo. and it could block the prv-induced cell apoptosis as well. abbreviations amp: antimicrobial peptide; prv: pseudorabies virus; tcid 50 : tissue culture infective dose assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the united states emergence of porcine epidemic diarrhea virus in the united states: clinical signs, lesions, and viral genomic sequences inactivated and subunit vaccines against porcine reproductive and respiratory syndrome: current status and future direction s1 domain of the porcine epidemic diarrhea virus spike protein as a vaccine antigen pathogenesis and transmission of swine-origin 2009 a(h1n1) influenza virus in ferrets new variants of porcine epidemic diarrhea virus, china antimicrobial peptides: do they have a future as therapeutics? in: antimicrobial peptides defensins: antimicrobial peptides of innate immunity antimicrobial peptides: promising alternatives in the post feeding antibiotic era the immunology of host defence peptides: beyond antimicrobial activity inhibition of hiv infection by caerin 1 antimicrobial peptides the chemistry and biological activities of peptides from amphibian skin secretions generation of a dual-target, safe, inexpensive microbicide that protects against hiv-1 and hsv-2 disease a review of the design and modification of lactoferricins and their derivatives defensins at the mucosal surface: latest insights into defensin-virus interactions generation and characterization of ul41 null pseudorabies virus variant in vitro and in vivo role of the pseudorabies virus gi cytoplasmic domain in neuroinvasion, virulence, and posttranslational n-linked glycosylation vaccines against pseudorabies virus (prv) caerin1.1 suppresses the growth of porcine epidemic diarrhea virus in vitro via direct binding to the virus the use of the antimicrobial peptide piscidin (pcd)-1 as a novel anti-nociceptive agent single amino acid substitutions at specific positions of the heptad repeat sequence of piscidin-1 yielded novel analogs that show low cytotoxicity as well as in vitro and in vivo anti-endotoxin activity broad activity against porcine bacterial pathogens displayed by two insect antimicrobial peptides moricin and cecropin b a crispr/cas9 and cre/lox system-based express vaccine development strategy against re-emerging pseudorabies virus establishment and clinical application of a multiplex reverse transcription pcr for detection of porcine epidemic diarrhea virus, porcine transmissible gastroenteritis virus and porcine group a rotavirus porcine reproductive and respiratory syndrome virus (prrsv) suppresses interferonbeta production by interfering with the rig-i signaling pathway porcine epidemic diarrhea virus orf3 gene prolongs s-phase, facilitates formation of vesicles and promotes the proliferation of attenuated pedv the ubiquitin-proteasome system is required for the early stages of porcine circovirus type 2 replication antiviral effect of diammonium glycyrrhizinate and lithium chloride on cell infection by pseudorabies herpesvirus inactivation of viruses infecting ectothermic animals by amphibian and piscine antimicrobial peptides anti-hiv-1 activity of indolicidin, an antimicrobial peptide from neutrophils antiviral peptides targeting the west nile virus envelope protein novel influenza virus ns1 antagonists block replication and restore innate immune function fusion core structure of the severe acute respiratory syndrome coronavirus (sars-cov): in search of potent sars-cov entry inhibitors inactivation of frog virus 3 and channel catfish virus by esculentin-2p and ranatuerin-2p, two antimicrobial peptides isolated from frog skin piscidin: antimicrobial peptide of rock bream modulation of the immune-related gene responses to protect mice against japanese encephalitis virus using the antimicrobial peptide, tilapia hepcidin 1-5 publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations not applicable. availability of data and materials data and materials are available upon request by the corresponding author.ethics approval and consent to participate all of the animal experimental protocols were reviewed and approved by the ethics committee of huazhong agricultural university. not applicable. the authors declare that they have no competing interests. key: cord-280795-wtrt13ij authors: han, yu-tsung; tsai, chia-sheng; chen, ya-chio; lin, ming-kuem; hsu, yau-heiu; meng, menghsiao title: mutational analysis of a helicase motif-based rna 5′-triphosphatase/ntpase from bamboo mosaic virus date: 2007-10-10 journal: virology doi: 10.1016/j.virol.2007.05.013 sha: doc_id: 280795 cord_uid: wtrt13ij the helicase-like domain of bamv replicase possesses ntpase and rna 5′-triphosphatase activities. in this study, mutational effects of the helicase signature motifs and residue l543 on the two activities were investigated. either activity was inactivated by k643a-s644a, d702a, d730a, r855a, or l543p mutations. on the other hand, q826a, d858a and l543a had activities, in terms of k(cat)/k(m), reduced by 5to 15-fold. amppnp, a nonhydrolyzable atp analogue, competitively inhibited rna 5′-triphosphatase activity. analogies of mutational effects on the two activities and approximation of k(i(amppnp)) and k(m(atp)) suggest that the catalytic sites of the activities are overlapped. mutational effects on the viral accumulation in chenopodium quinoa indicated that the activities manifested by the domain are required for bamv survival. results also suggest that q826 in motif v plays an additional role in preventing tight binding to atp, which would otherwise decrease further rna 5′-triphosphatase, leading to demise of the virus in plant. bamboo mosaic virus (bamv), a member of potexvirus genus belonging to the alphavirus-like superfamily, has a positive-strand rna genome (∼ 6.4 kb) with a 5′ m 7 gpppg cap structure and a 3′ poly(a) tail . open reading frame 1 of the viral genome encodes a 155-kda replicase consisting of mrna capping enzyme, helicase-like and rnadependent rna polymerase (rdrp) domains sequentially from n to c termini. a disordered region of more than 100 amino acid residues and a proline-rich segment separate respectively the neighboring functional domains. these two flexible regions may allow one domain to interact with others dynamically during the viral replication process. the capping enzyme domain, expressed in membrane fractions of yeast, exhibited an s-adenosylmethionine-dependent guanylyltransferase activity by which gtp is methylated to form m 7 gtp before the m 7 gmp moiety is further transferred to the 5′-diphosphate end of mrna to form the m 7 gpppn cap structure (huang et al., 2005; li et al., 2001a) . such distinctive capping activity has also been demonstrated in semliki forest virus (sfv) (ahola and kääriäinen, 1995) , brome mosaic virus (ahola and ahlquist, 1999; kong et al., 1999) , tobacco mosaic virus (tmv) (merits et al., 1999) and hepatitis e virus (magden et al., 2001) ; thus, it is probably a common feature of the capping enzymes from the alphavirus-like superfamily. the e. coli-expressed helicase-like domain possessed both rna 5′-triphosphatase and ntp hydrolase activities (li et al., 2001b) . with the rna 5′triphosphatase and the aforementioned capping enzyme activities, a cap structure could be formed at the 5′ end of bamv mrna in vitro. the recombinant rdrp domain showed a template-dependent rna polymerase activity and had preferential binding activity to the 3′ noncoding region of the viral rna (huang et al., 2001; li et al., 1998) . rna 5′-triphosphatase specifically cleaves the 5′ γ-phosphate out of the nascent mrna in the first reaction step toward the cap formation. the documented rna 5′-triphosphatases can be grouped into three classes according to their primary structures and the catalytic mechanism employed. the meta-zoan and plant enzymes are of the metal-independent cysteine phosphatase type and distinguish themselves by possessing an hc(x) 5 rs/t motif, in which the cysteine residue acts as a catalytic nucleophile within the catalytic pathway (changela et al., 2001; takagi et al., 1997) . the enzymes from fungi, protozoa, and some dna viruses constitute a metal-dependent phosphohydrolases class with characteristic of possessing two essential glutamate-containing motifs (ho et al., 1998; martins and shuman, 2003) . rna triphosphatases, derived from rna helicases or helicase-like proteins, constitute another metaldependent phosphohydrolases class. this class includes the enzymes identified from rna viruses such as reovirus , alphavirus (vasiljeva et al., 2000) , dengue virus (matusan et al., 2001) , coronavirus , and bamv (li et al., 2001b) . both classes of the metal-dependent rna triphosphatases are also capable of hydrolyzing nucleoside triphosphates to nucleoside diphosphates and inorganic phosphate. according to motif-based classification, helicase-like proteins from rna viruses have been classified into three superfamilies (sf) (kadaré and haenni, 1997) . members of sf1 share similarity to nsp2 of alphavirus, while ns3-like proteins of potyvirus, flavivirus and pestivirus, and 2c-like proteins of picornavirus are representatives of sf2 and sf3, respectively. across the three sf, gks/t sequence of motif i (walker a site) is conserved, whereas the consensus sequences of motif ii (walker b site) are varied, with de/d sequences in sf1 and sf3 and dexh in sf2. based on the classification principle, the helicase-like domain of bamv replicase can be grouped into sf1. fig. 1 shows comparison of partial amino acid sequences of the bamv domain and some of the sf1 members. in relation to enzymatic activities, all three sf proteins have atpase activity. an rna helicase activity has also been broadly corroborated on proteins of sf2; however, the activity was so far demonstrated only on a couple of sf1 proteins, e.g., nsp2 of sfv (gomez de cedron et al., 1999) and the helicase domain of tmv replicase (goregaoker and culver, 2003) . like the helicase-like domain of bamv replicase, nsp2 of sfv has also been reported to have rna 5′-triphosphatase activity (vasiljeva et al., 2000) . ntp binding and hydrolysis functions of motif i and ii of helicases have been suggested by numerous mutational studies and confirmed by crystal structures of helicases such as pcra of bacillus stearothermophilus (subramanya et al., 1996; velankar et al., 1999) , rep of escherichia coli (korolev et al., 1997) and ns3 of hepatitis c virus (yao et al., 1997) . the lysine residue of motif i interacts with the phosphates of mgatp/mgadp and the threonine or serine ligates the mg 2+ ion. the first aspartic acid of motif ii also coordinates mg 2+ ion and the following glutamate or aspartate residue may act as catalytic base in atp hydrolysis. by contrast, functions of other signature motifs, particularly those of sf1, are relatively less addressed. as a step toward better understanding the relationship between activities and structures of the helicase-like domain of bamv replicase, we set out to investigate the importance of each signature motif to its ntpase and rna 5′-triphosphatase activities by mutational and kinetic analyses. results of this study strongly sug-gest a common catalytic site for the removal of 5′γ-phosphate from ntp and rna. the relation between the enzymatic activities in vitro and the viral replication in vivo is also discussed in this study. previous studies demonstrated that the helicase-like domain of bamv replicase exhibits an mg 2+ /mn 2+ -dependent γphosphohydrolase activity toward both nucleoside triphosphate and rna (li et al., 2001b) . the former (ntpase) could be a prerequisite for the putative rna helicase activity, and the latter (rna 5′-triphosphatase) could be involved in the cap structure formation. substitution of gaa for gks in motif i abolished ntpase as well as rna 5′-triphosphatase activities. in the present study, we examined the mutational effects of other conserved motifs of sf1 helicases with respect to these two activities. leucine at position 543 was also included in the mutation list because the accumulation level of the viral coat protein decreased significantly in protoplast of nicotiana benthamiana as leu543 to proline mutation was introduced into the viral replicase . in addition, a deih sequence immediately downstream motif vi was mutated because it is analogous to dexh box of motif ii of sf2. each of the targeted residues, as indicated in fig. 1 , was replaced by alanine except leu543 that was also replaced by proline. all the proteins were expressed in e. coli and purified by immobilized metal affinity and anionic exchange chromatography as described in materials and methods. the purification results are shown in fig. 2 . the importance of the mutated residues to atp hydrolysis activity was first analyzed qualitatively by tlc assay (fig. 3) . alanine substitution at k643-s644 or at d702 reduced the activity to extents similar to the background level. mutation of d730 or r855 to alanine or l543 to proline also resulted in severe damage to atp hydrolysis activity. in contrast, q826a and d858a remained active but with diminished activities. atpase activity manifested by helicases of sf2, e.g., ns3 proteins of yellow fever virus , hepatitis c virus (suzich et al., 1993) and bovine viral diarrhea pestivirus , is usually stimulated by single stranded rna. effect of rna on atpase activity of the bamv helicaselike domain was also examined in this study. inclusion of an rna transcript, corresponding to the first 200 nucleotides of bamv genome, in the reactions did not cause apparent changes in the atpase activity of any of the tested enzymes. to better characterize the ntpase activity, steady-state rates of the reaction were measured by enzyme-coupled assay, in which ntp hydrolysis was coupled to nadh oxidation. apparent k m and k cat of the wild-type enzyme toward four different mononucleotides were subsequently calculated based on ntp concentration dependences of rate (table 1 ). all four mononucleotides could be hydrolyzed by the wild-type enzyme at rates with apparent k m value ranging from 0.15 to 0.33 mm and apparent k cat from 24 to 67 s − 1 . the specificity constants (k cat /k m ) of the reactions are comparable to that of λ1 of reovirus and nsp13 of sars coronavirus and larger than that of nsp2 of sfv and ns3 of dengue virus (matusan et al., 2001; vasiljeva et al., 2000) . mutational effects of the targeted amino acid residues on the apparent kinetic parameters of atpase were subsequently analyzed by enzyme-coupled assays. consistent with tlc results, proteins with specified mutation in motif i, ii, iii or vi did not show atpase activity to any appreciable extent (not shown). l543p mutant was also inactive; however, l543a was active with an unchanged k m but a 14-fold reduced k cat (table 2) . d858a had k m and k cat reduced by factors of 2 and 10, respectively. q826a had 17-fold and 90-fold decreases in values of k m and k cat , respectively. it is worth noting that the specificity constant of q826a decreased only by a factor of 5.3; this and overtime incubation may account for the apparent atpase activity of q826a shown in the previous tlc assay. the significantly enhanced affinity to atp should account for, to some extent, the dramatic decrease of k cat in q826a. besides ntpase activity, the helicase-like domain of bamv replicase also catalyzes the removal of 5′ γ-phosphate from triphosphate-terminated rna. results of typical experiments with wild-type enzyme are shown in fig. 4 . phosphate increased steadily with time in the first 5 min under the reaction condition fig. 1 . alignment of partial amino acid sequences of the helicase-like domains of some rna viral replicases. the consensus residues within each signature motif of sf1 helicases are shown in bold. residues mutated in this study on bamv protein are indicated by asterisk. protein secondary structure was predicted at the psipred protein structure prediction server (http://bioinf.cs.ucl.ac.uk/psipred/). the rectangle and arrow symbolize the α-helix and β-strand, respectively. bamv, pvx, tmv, tymv, and hev represent bamboo mosaic virus, potato virus x, tobacco mosaic virus, turnip yellow mosaic virus and hepatitis e virus, respectively. (panel a). in addition, phosphates released were roughly proportional to the applied amounts of enzyme within a short period of reaction time (panel b). to define the mutational effects on the activity, reactions catalyzed by wild-type and various mutants were allowed to occur under conditions of enzyme excess (fig. 5) . the activities of k643a-s644a and d702a were nearly abolished. likewise, l543p, d730a and r855a had activities hardly to be observed. the apparent activity of l543a was comparable to that of wild type, while that of q826a and d858a was reduced noticeably. to characterize the effects in detail, reaction rates of l543a, q826a, d858a and the wild-type enzyme were determined at different rna concentrations, and the kinetic parameters were subsequently calculated (table 2) . considering the limitations, such as suboptimal substrate concentration, in data processing, the determined values of k m and k cat were apparent. still, they should be helpful to evaluate the mutational effects. comparing with mononucleotides, rna was hydrolyzed at much slower rates. alanine substitution at l543, q826 or d858 had unfavorable effects on both rna binding and catalysis as evidenced by the increase of apparent k m and the decrease of apparent k cat , respectively. in general, the specificity constants of the three mutants for rna hydrolysis reduced approximately 5-to 14-fold. overall, effects of the investigated mutations on atpase and rna 5′-triphosphatase were parallel, implying that the catalytic sites of the two activities are overlapped. to support the notion, effects of amppnp, a nonhydrolyzable analogue of atp, and amp on rna 5′-triphosphatase activity were examined. amppnp exerted an inhibitory effect on the activity (fig. 6a ). the higher concentration of amppnp, the greater extent of inhibition was observed. by contrast, amp did not significantly affect rna 5′-triphosphatase activity even as its concentration was up to 2 mm (fig. 6b) , suggesting that the 5′terminal γand β-phosphate groups of substrates are the major determinants for the competition. to know the inhibition mode of amppnp, the dependence of rate on rna substrate concentration was determined under different amppnp concentration (fig. 7a ). double-reciprocal plot of the data showed an approximately unchanged v max (fig. 7b) , suggesting that amppnp acted as a competitive inhibitor. the apparent k i value of amppnp in inhibiting rna 5′-triphosphatase activity the enzymatic activity was determined at 20°c by enzyme-coupled assay in 1 ml solution that contained 10 pmol enzyme, 0.1 to 3 mm ntp and other buffer components as described under materials and methods except that the amounts of pyruvate kinase were increased up to 50, 75 and 300 u for gtpase, utpase and ctpase assay, respectively, to assure the rate of ntp hydrolysis being the limiting step within the coupling reaction. was calculated to be 93 μm, which is comparable to the k m value of atp. probably, the catalytic sites for hydrolyzing 5′ γphosphate from rna and mononucleotide are identical or extensively overlapped. the competence of bamv to multiply in vivo was investigated by inoculating plasmid pcbg into leaves of c. quinoa, in which the viral replication and cell-to-cell movement could b atpase activity was determined at 20°c by enzyme-coupled assay in 1-ml solution that contained 0.1 to 3 mm atp, 10 to 600 pmol enzyme and other buffer components as described under materials and methods. data are averages of at least two independent experiments. c rna 5′-triphosphatase activity was determined by tlc analysis. reactions were carried out at 20°c in 3-μl solution that contained 1 pmol enzyme, 10 to 80 μm 5′-[γ-32 p]rna, and other buffer components as described under materials and methods. data are averages of two independent experiments. be monitored by the appearance of green fluorescence because the expression of the introduced gfp depends on the fulfillment of bamv replication (lin et al., 2004) . to see the mutational effects, each of the selected mutations was introduced into pcbg, and the resulting mutant plasmid was mechanically inoculated into plant cells. as shown in fig. 8 , spots with green fluorescence began to appear on leaves of plants infected with wild type, l543a, or d858a virus a week later after inoculation. the respective frequency and average diameter of fluorescent loci appeared on leaves were similar, suggesting that the three variants replicated equally well in c. quinoa. local lesions formed later on leaves that had shown green fluorescence spots earlier (fig. 9) . no signs of green fluorescence or disease symptoms were noted on leaves of plants infected with other mutant viruses, including that carries q826a mutation. repeated experiments with wild type, l543a, q826a and d858a confirmed the negative result of q826a mutation. disability on rna 5′-triphosphatase alone is sufficient to account for the replication incompetence of those carrying specified mutation in motif i, ii, iii, and vi and l543p since formation of 5′ cap at viral mrna is essential for substantial viral protein translation. however, the reasons for the opposite effects of the d858a and q826a mutations in plant are uncertain because the two mutations decreased rna 5′-triphosphatase activity to similar extents. would it be possible that alanine substitution at q826 affects not only the enzymatic activity but also the protein stability? protein stabilities of wild type, l543a, q826a and d858a were, therefore, investigated under 25°c by measuring their residual enzymatic activity as a function of time. the inactivation of the proteins followed first-order kinetics. the half lives (t 1/2 ) of wild type, l543a and q826a were approximately 2 h, whereas t 1/2 of d858a was 40 min (data not shown), indicating that protein stability would not be the cause. alternatively, the distinct feature of q826a on atpase activity might underlie the failure of the mutant virus to replicate in vivo. the mutant protein might not be capable of providing sufficient energy by hydrolyzing atp to the putative helicase activity, or the tight binding of atp deteriorated further the weakened rna 5′-triphosphatase activity. activity of rna 5′-triphosphatase was assayed in the presence of 0.3 mm atp, which is within physiological concentration range (hampp et al., 1982; usuda, 1988) , to explore the latter possibility (fig. 10) . under the competition conditions, rna 5′-triphosphatase activities of wild type and d858a remained approximately 30%, whereas little was left in q826a mutant. the results suggest that rna and mononucleoside triphosphate could have reciprocal inhibitory effects in vivo; and the deterioration of rna 5′-triphosphatase activity might be simply enough to disable the replication function of q826a mutant virus. helicases are defined as proteins that catalyze the separation of duplex nucleic acids into single strands in an ntp-dependent reaction. sequence comparison of the helicase-like proteins from rna viruses has disclosed the conservation of several signature motifs and grouped them into three sf (kadaré and haenni, 1997) . functions of helicase motifs have been addressed through mutational and structural analyses owing to the involvement of helicases in various important biological processes. as regards sf1, crystal structures of dna helicases pcra (subramanya et al., 1996; velankar et al., 1999) and rep (korolev et al., 1997) could provide us insights into the relationships between structures and functions of the proteins. in brief, residues on both motif i and ii are involved in the binding of atp through phosphate group recognition and mg 2+ coordination, while the second conserved acidic residue of motif ii acts as catalytic base in atp hydrolysis. other residues such as the glutamine of motif iii and the arginine of motif vi also participate in accommodating the γ-phosphate group of atp. as with other potexvirus, bamv replicase contains a helicase-like domain which can be classified into sf1. in this study, contributions of the conserved motifs of the helicase-like domain to ntpase and rna 5′-triphosphatase were investigated by mutagenesis. with respect to atpase activity, motifs i and ii are essential, consistent with the suggestions by crystal structures and mutational results reported in numerous literatures. mutations at the aspartate of motif iii and the arginine of motif vi brought on severe damages to the activity, also consistent with their involvement in atp binding. function of deih sequence immediately downstream motif vi is not analogous to that of dexh box (motif ii) of sf2 helicases because mutation of the sequence merely caused about 10-fold decrease in k cat value. q826 in motif v seems to avoid the tight binding of the protein to ground-state atp since alanine substitution at the residue reduced value of k m(atp) notably. the otherwise enhanced affinity to atp in q826a not only had adverse effect on atp hydrolysis but also caused significant interference with rna 5′-triphosphatase activity. l543, located in a predicted short β-strand outside the helicase motifs, might have a structural role supporting the active-site architecture for catalyzing atp hydrolysis. for one thing, l543 bears a hydrophobic side chain; for another, the destructive effect caused by proline substitution could be reversed to a certain extent by alanine substitution. nonetheless, this proposition needs to be verified by further structural analysis. as for rna 5′-triphosphatase activity, the effects caused by the various mutations were similar to those on atpase activity, except for q826a: the alanine substitution increased k m(rna) slightly for the rna 5′-triphosphatase activity, while decreasing k m(atp) for the ntpase activity more than 17-fold. the importance of the mutated residues in the viral accumulation in plant was also investigated. mutations of residues within the conserved motifs would disable the viral replication in vivo. by contrast, the two mutations outside the motifs, l543a and d858a, had insignificant consequence. the helicase motifs in 1a protein of brome mosaic virus have also been shown to play essential roles in rna replication in vivo by presumably being involved in viral rnas import (wang et al., 2005) . another aim of this study is to know whether the two enzymatic activities occur at a single or two independent catalytic sites. the generally parallel effects of the mutations on the two activities suggest that the protein employs the same amino acid constellation for the removal of 5′ γ-phosphate from rna and ntp. approximation between k i(amppnp) in rna 5′-triphosphatase competition assays and k m(atp) in atpase assays supports the same idea. still, we cannot rule out another possibility that the substrates might bind to two closely related sites with the atpase activity driving a conformational change that activates the rna 5′-triphosphatase activity, considering the opposite mutational effects on k m(atp) and k m(rna) of q826a. further structural evidence is needed to clarify the argument. nonetheless, employment of a common catalytic site for ntpase and rna 5′-triphosphatase activities has also been suggested on several helicase motif-base proteins such as sfv nsp2 (balistreri et al., 2007) , reovirus λ1 , sars-coronavirus nsp13 and dengue virus nsp3 proteins (bartelma and padmanabhan, 2002) . this raises a question as whether rna 5′-triphosphatase activity is an attendant function of helicases, or it is an adaptive outcome in the course of viral evolution. bamv genome contains two copies of helicase-like domains. one is the domain within viral replicase, the other is the p28 movement protein encoded by triple gene block. with the essential role to the movement of virus in the infected plant, p28 protein also possesses ntpase and rna-binding activities (wung et al., 1999) ; however, it did not show rna 5′-triphosphatase activity (li et al., 2001b) . taken together with the fact that only a few helicases (or helicase-like proteins) have been reported to have rna 5′-triphosphatase activity, we speculate that the 5′ γphosphohydrolase activity for rna molecule has evolved from ntpase activity driven by the demand for functional capping machinery, by which the mrna of rna viruses can be capped within cytoplasm of the infected cells. in spite of lacking explicit biochemical data, the helicase-like domain of bamv replicase has been thought to have rna helicase activity, which may be required for resolving intramolecular base pairing in the template rna and/or preventing the formation of extensive base pairing between template and the nascent complementary strand during rna replication process. is it possible that a protein domain can participate in rna replication while it is also responsible for the removal of 5′ γ-phosphate from the nascent rna to allow cap structure formation? with the help of the flanking flexible hinges, the helicase-like domain may be able to work with the rdrp or the capping domains at different steps during replication process. yet, we cannot rule out another possibility at this moment that the function of the helicase-like domain is for the formation of cap structure while the helicase activity required for bamv replication is provided by hosts. deferring the uncertainty of helicase activity, rna 5′-triphosphatase itself is definitely sufficient to dictate the survival of bamv in plant. mutations that abolished the enzymatic activity in vitro could result in the demise of the virus in c. quinoa. nonetheless, ∼7% of the wild-type activity, in terms of k cat /k m , seemed to be enough for the need since bamv bearing d858a mutation survived. the failure of q826a mutant in c. quinoa is intriguing because it has even higher rna 5′-triphosphatase function than d858a. further inhibition of the weaken rna 5′triphosphatase activity by tight binding of atp in vivo might account for the fatal outcome, indicating the need of a multiplefunction enzyme to coordinate all its activities for the survival of the organism. plasmid phwt, a pet32 derived-vector containing a cdna fragment encoding amino acids 514-892 of bamv replicase, was used for protein expression in e. coli as described previously (li et al., 2001b) . plasmid pcbg is an infectious clone of recombinant bamv, in which a green fluorescence protein (gfp) gene preceded by a duplicated coat protein promoter is situated between triple gene block and coat protein-coding region as described previously (lin et al., 2004) . initial transcription of the recombinant bamv genome from pcbg in plant is driven by 35s promoter of cauliflower mosaic virus. plasmid puhel is a puc18-based vector that contains an sphidigested fragment (4168 nt) isolated from pcbg. site-directed mutagenesis was done on phwt and puhel based on the protocol of quikchange site-directed mutagenesis kit (stratagene). after confirming the mutations with abi prism 3100 auto sequencer (perkinelmer), the sphi-digested fragment from the mutated puhel was put back into pcbg. the helicase-like domain of bamv replicase, fused with a thioredoxin, a poly-histidine tag, and an s-tag at the n terminus, was expressed in e. coli novablue cells (novagen) and purified as described previously with minor modifications (li et al., 2001b) . briefly, the recombinant protein, expressed as inclusion bodies, was first dissolved in urea-containing lysis buffer (50 mm tris [ph 7.5], 150 mm kcl, 0.1% brij-35, 10% glycerol, 10 mm β-mercaptoethanol, 1 mm pmsf and 8 m urea). refolding of the protein was done at 4°c by dropping 1 ml denatured protein solution (∼ 15 mg/ml) into 25 ml stirred lysis buffer. after centrifugation, the refolded protein in the supernatant was then purified by ni 2+ -nitriloacetic acid resin (qiagen) followed by q sepharose (pharmacia) using a linear gradient of nacl (20-500 mm) in equilibrium buffer (50 mm tris [ph 8.0], 0.1% brij-35, 20% glycerol, 10 mm β-mercaptoethanol, and 5 mm egta). the eluted protein was finally subjected to dialysis against equilibrium buffer containing additional 20 mm kcl. rna transcript consisting of the first 50 nucleotides of the plus-strand rna of bamv was used as substrate for rna 5′triphosphatase assay. the corresponding cdna fragment preceded by t7 promoter was first amplified from a cdna clone of bamv by pcr and purified through steps of page (10%), gel extraction and ethanol precipitation. the amplified cdna fragment was then used as template to produce 5′-[γ-32 p]rna in a 20-μl in vitro transcription reaction that contained 0.3 μg template dna, 30 mm ntp (7.5 mm each), 0.05 mci [γ-32 p] gtp (6000 ci/mmol, perkinelmer), 2 μl t7-megashortscript enzyme mix (ambion) and 1× t7 transcription buffer. after 2 h of incubation at 37°c, the reaction product was treated with 2 units of rnase-free dnase i (ambion) at 37°c for 15 min and the 5′-labeled rna was purified through 8 m urea-page (10%), gel extraction and ethanol precipitation. rna concentration was determined according to its optical density at 260 nm measured with nanodrop spectrophotometer. a 200nucleotide 5′-terminal fragment of the plus-strand rna of bamv was also prepared based on the above procedure and described before (li et al., 2001b) . ntpase activity was analyzed by detecting the liberated [α-32 p]ndp from [α-32 p]ntp on a polyethyleneimine (pei)cellulose thin-layer chromatography (tlc) plat or by the decreasing rate of od 340 nm in an enzyme-coupled assay in which ntp hydrolysis was linked to nadh oxidation through activities of pyruvate kinase and lactate dehydrogenase as described previously (li et al., 2001b) . in principle, the reactions were carried out at 20°c in solution containing 50 mm tris [ph 7.5], 5 mm mgcl 2 , 5 mm dtt and indicated amounts of substrate and protein. for enzyme-coupled assays, the solution also contained 2 mm phosphoenol pyruvate, 0.2 mm nadh, 20 u of pyruvate kinase and 20 u of lactate dehydrogenase unless otherwise indicated. rna 5′-triphosphatase activity was analyzed by measuring the γ-phosphate released from 5′-[γ-32 p]rna on pei tlc plate using a phosphorimager (typhoon 9200). standard reaction was performed at 20°c in solution containing 50 mm tris [ph 7.5], 5 mm mgcl 2 , 5 mm dtt, 5 u of rnase inhibitor (takara) and specified amounts of protein and 5′-[γ-32 p]rna. reaction was stopped by adding edta to final 25 mm. tlc was developed using 0.15 m licl-0.15 m formic acid. inhibition experiments of rna 5′-triphosphatase were conducted in the presence of indicated amounts of atp, amppnp, or amp. the amount of radiolabeled products on tlc plate was quantified according to its pixel count against a standard curve of serial diluted 5′-[γ-32 p]rna versus their respective pixels. the reaction rate was estimated from a period of reaction during which no more than 15% of the initial rna substrate was hydrolyzed. proportional ratio between the product released and the enzyme applied under this criterion (fig. 4b) suggests that the rates estimated should be close to the initial rate. the mechaelis-menten constant, k m and v max were determined from lineweaver-burk plot using grafit software. inhibition of amppnp was assessed using lineweaver-burk plot in the presence of different fixed concentrations of amp-pnp. the inhibition constant, k i , was calculated according to the dependence of the slope, k m /v max , of the lineweaver-burk plot on the inhibitor concentration. catalytic constant, k cat , was calculated based on the equation v max = k cat × [e] 0 where [e] 0 is the molar concentration of the protein used in assays. plasmid pcbg and its derivatives were inoculated mechanically into plant leaves of 3-week-old c. quinoa according to the method described previously with minor modifications . in short, 2 μg dna in 10 μl aqueous solution was rubbed gently over the surface of the selected leaf that had been dusted with a thin layer of sterile carborundum. each plasmid dna was applied to at least 9 leaves, 3-4 leaves a plantlet and total 3 plantlets. fluorescent images of inoculated leaves were obtained 7 days post-inoculation with a fluorimager with an excitation filter of 488 nm and an emission filter using calibration files. spots with green fluorescence were further observed under a fluorescent microscope. local lesions that appeared later on leaves could be observed by naked eyes. putative rna capping activities encoded by brome mosaic virus: methylation and covalent binding of guanylate by replicase protein 1a reaction in alphavirus mrna capping: formation of a covalent complex of nonstructural protein nsp1 with 7-methyl-gmp enzymatic defects of the nsp2 proteins of semliki forest virus temperature-sensitive mutants expression, purification, and characterization of the rna 5′-triphosphatase activity of dengue virus type 2 nonstructural protein 3 characterization of the reovirus λ1 protein rna 5′-triphosphatase activity characterization of the nucleoside triphosphate phosphohydrolase and helicase activities of the reovirus λ1 protein structure and mechanism of the rna triphosphatase component of mammalian mrna capping enzyme rna helicase of semliki forest virus replicase protein nsp2 oligomerization and activity of the helicase domain of the tobacco mosaic virus 126-and 183-kilodalton replicase proteins adenylate levels, energy charge, and phosphorylation potential during dark-light and light-dark transition in chloroplasts, mitochondria, and cytosol of mesophyll protoplasts from avena sativa l yeast and viral rna 5′ triphosphatases comprise a new nucleoside triphosphatase family evolution of bamboo mosaic virus in a nonsystemic host results in mutations in the helicase-like domain that cause reduced rna accumulation sequences at the 3′ untranslated region of bamboo mosaic potexvirus rna interact with the viral rna-dependent rna polymerase mrna guanylation catalyzed by the s-adenosylmethionine-dependent guanylyltransferase of bamboo mosaic virus human coronavirus 229e nonstructural protein 13: characterization of duplex-unwinding, nucleoside triphosphatase, and rna 5′-triphosphatase activities multiple enzymatic activities associated with severe acute respiratory syndrome coronavirus helicase virus-encoded rna helicases the n-terminal half of the brome mosaic virus 1a protein has rna capping-associated activities: specificity for gtp and s-adenosylmethionine major domain swiveling revealed by the crystal structures of complexes of e. coli rep helicase bound to single-stranded dna and adp identification and characterization of the escherichia coli-expressed rnadependent rna polymerase of bamboo mosaic virus characterization of the adomet-dependent guanylyltransferase activity that is associated with the n terminus of bamboo mosaic virus replicase the helicase-like domain of plant potexvirus replicase participates in formation of rna 5′ cap structure by exhibiting rna 5′-triphosphatase activity a satellite rna associated with bamboo mosaic potexvirus nucleotide sequence of the genomic rna of bamboo mosaic potexvirus arg-16 and arg-21 in the n-terminal region of the triple-gene-block protein 1 of bamboo mosaic virus are essential for virus movement virus-specific mrna capping enzyme encoded by hepatitis e virus mapping the triphosphatase active site of baculovirus mrna capping enzyme lef4 and evidence for a two-metal mechanism mutagenesis of the dengue virus type 2 ns3 protein within and outside helicase motifs: effects on enzyme activity and virus replication virus-specific capping of tobacco mosaic virus rna: methylation of gtp prior to formation of covalent complex p126-m7gtp crystal structure of a dexx box dna helicase hepatitis c virus ns3 protein polynucleotide-stimulated nucleoside triphosphatase and comparison with the related pestivirus and flavivirus enzymes an rna 5′-triphosphatase related to the protein tyrosine phosphatases rna-stimulated ntpase activity associated with the p80 protein of the pestivirus bovine viral diarrhea virus adenine nucleotide levels, the redox state of the nadp system, and assimilatory force in nonaqueously purified mesophyll chloroplasts from maize leaves under different light intensities identification of a novel function of the alphavirus capping apparatus: rna 5′-triphosphatase activity of nsp2 crystal structures of complexes of pcra dna helicase with a dna substrate indicate an inchworm mechanism brome mosaic virus 1a nucleoside triphosphatase/helicase domain plays crucial roles in recruiting rna replication templates rna-stimulated ntpase activity associated with yellow fever virus ns3 protein expressed in bacteria identification of the rna-binding sites of the 28 kda movement protein of bamboo mosaic potexvirus structure of the hepatitis c virus rna helicase domain this work was supported by grants, nsc 94-2752-b-005-012-pae, from the national science council, taiwan, republic of china. key: cord-257494-242k58ll authors: bastos, paulo; trindade, fábio; da costa, joão; ferreira, rita; vitorino, rui title: human antimicrobial peptides in bodily fluids: current knowledge and therapeutic perspectives in the postantibiotic era date: 2017-01-17 journal: med res rev doi: 10.1002/med.21435 sha: doc_id: 257494 cord_uid: 242k58ll antimicrobial peptides (amps) are an integral part of the innate immune defense mechanism of many organisms. due to the alarming increase of resistance to antimicrobial therapeutics, a growing interest in alternative antimicrobial agents has led to the exploitation of amps, both synthetic and isolated from natural sources. thus, many peptide‐based drugs have been the focus of increasing attention by many researchers not only in identifying novel amps, but in defining mechanisms of antimicrobial peptide activity as well. herein, we review the available strategies for the identification of amps in human body fluids and their mechanism(s) of action. in addition, an overview of the distribution of amps across different human body fluids is provided, as well as its relation with microorganisms and infectious conditions. human antimicrobial peptides (amps) represent approximately 10% of all curated amps catalogued to date. 1 human host defense peptides are an intrinsic part of the innate immune system and exhibit a broad activity spectrum against bacteria, fungi, viruses, and parasites while amps can be antibacterial (abps), antifungal, antiprotist, antiviral, anticancer, antiparasitic, insecticidal, spermicidal, chemotactic, antioxidant, protease inhibitors, or even exhibit wound healing properties (supporting information table s1), their scope of action overlaps considerably and some peptides show activity at several levels (fig. 2 ). [1] [2] [3] [4] [5] for instance, on the one hand, human plasma adrenomedullin-derived peptides are active against multiple bacteria species, human urinary and gingival fluid calcitonin gene-related peptide displays antimicrobial activity against several bacteria and fungi species, and human neutrophil peptides (hnps)/defensins isolated from most biological fluids display activity against several bacterial, fungal, and viral species (fig. 2) . on the other hand, dozens of human amps known to date display antimicrobial activity against the same human colonizers or pathogens, including escherichia coli, pseudomonas aeruginosa, and staphylococcus aureus (figs. 2 and 3) . also, it is intriguing to observe that even though some amps display broad activity spectra, others seem to be anywhere from species-to kingdom-specific (fig. 2) . while likely to be confounded global network depicting the distribution of human antimicrobial peptides across biological fluids and their microbial targets. rectangular nodes correspond to biofluids, circular nodes to target species, and each edge correspond to a given gene encoding one or more antimicrobial peptides. the thicker the edge, the stronger is the association of a biofluid to a pathogen, representing increased number of antimicrobial peptides defending against such pathogen in such biofluid. also, pathogens represented by bigger nodes (e.g., escherichia coli, candida albicans, staphylococcus aureus) represent those that are targeted by more antimicrobial peptides across different biofluids. by observational bias (whereby some species, e.g., e. coli, tend to be tested more frequently than others), this observation also reflects that the activity spectra of amps depend not only on their physicochemical properties (which group them according to unique families) but also on target properties and on the environment/biological fluid in which they are found. as the large majority of amps identified to date are abps (ß83%, figs. 1-3) , most concepts and examples provided in this review will be based on results from studies focusing on abps, closely followed by those derived from studies on antiviral and antifungal peptides. however, the same principles tend to apply across all amps. amps are very potent cationic molecules displaying minimum inhibitory concentrations (the minimum concentration that prevents bacterial growth) as low as 1-4 μg/ml, 6 which highlights their promise as broad-spectrum antimicrobial agents. furthermore, amps act more rapidly than conventional antibiotics and are not affected by the typical resistance mechanisms involving conventional drugs, making them very attractive for therapeutic purposes. in addition, amps are not mere microbicide agents, as their scope of action may encompass other functions, such as cellular development and immune system modulation. for instance, fetal keratinocytes express significantly more amps compared to neonatal and adult keratinocytes, despite the lower degree of exposition to the environment or to pathogenic agents. these a rough estimate of all amps catalogued to date (supporting information table s2 ) indicates 14.1% to be α-helices, followed by β-sheets (3.7%), and peptides presenting with both helices and β-sheets (3.7%). however, approximately 60% of all amps currently identified do not have a known 3d structure, while only 0.3% have a known structure that is neither a helix nor a β-sheet. excluding those that have unknown structures, 99 .2% of all amps are either α-helices and/or β-sheets, suggesting a highly conserved structure for a highly primordial biological function. secondary structures of human amps may include α-helices (e.g., ll-37), 34 β-sheets (e.g., defensin 1), 35 and extended peptides (e.g., indolicidin). 36 considering that β-sheets and α-helices in polypeptide chains typically contain three to ten amino acids per strand and 3.6 residues per turn, respectively, and that amino acid sequences can be virtually unlimited, one can easily envision that a given peptide can display a multitude of secondary structures and, thus, many diverse conformations (see 37 for protein secondary structures predictive approaches). among secondary structures, α-helices (in addition to being the most frequently encountered in nature) are the most regular and predictable, and, consequently, the most extensively studied. amps with linear α-helices are notably positively charged and amphipathic, but only adopt such secondary conformation upon binding to bacterial membranes. 38 therefore, their antimicrobial activity is directly dependent on the secondary structure. 39 in contrast, β-sheet amps possess well-defined conformations due to the presence of disulfide bridges formed between thiol groups in cysteines. in these peptides, such bridges are often required for antimicrobial activity. 40 contrariwise, bovine lactoferricin was shown to be effective against e. coli 0111 even when such bridges were blocked by pyridylethylation. 41 other human amps, such as human β-defensin 3 (hbd-3), present both α-helices and β-sheets. in the specific case of hbd-3, disrupting the three stabilizing disulfide bonds does not compromise its antimicrobial activity, but it does diminish its chemotactic properties. 42 furthermore, the correlation of the conformation with peptides' antimicrobial activity is not always as straightforward as one could imagine. for example, disruption of hbd-1's disulfide bonds results in peptides with free cysteines at the carboxy terminal that show increased antimicrobial activity against the pathogenic candida albicans and the gram-positive commensals bifidobacterium and lactobacillus. 43 moreover, linear extended peptides do not keep a fixed conformation in solution, and are enriched in one or more amino acids, particularly arginine, proline, and tryptophan. for instance, the amp histatin found in human saliva is enriched in histidine residues, 44 while prophenin is very rich in proline and phenylalanine residues. 45 when it comes to loop rich peptides, the presence of many prolines makes an amp much less likely to form amphipathic structures, adopting what is frequently referred to as polyproline helical type-ii (ppii) structures. these structures are specifically bound by sh3 domains, which are usually found in proteins that interact with other proteins and mediate assembly of specific protein complexes (upon proline-rich peptides binding). 46 human antibacterial peptides (abps), which compose the largest group of human amps, exhibit a weighted average net charge of +5.8 per peptide, which is considerably above the average net charge of all amps identified to date. also, despite being intuitive that the more positively charged an amp is, the more potency it will present, 47 human amps do not show greater potency or efficacy when compared to those of other species, suggesting that the environment and the presence of different amino acids (d and rare amino acids) also play a significant role. notwithstanding the large diversity of amps across human biologic fluids (figs. 2 and 3, table i ), it should be noted that amps are much more diverse across all species, than those identified in humans, which present rather conserved properties. in fact, some amps from other species are characterized by more intriguing sequences, structures, and physicochemical growth-regulated alpha protein properties. case in point, bacillus subtilis is known to produce several extremely potent lipopeptides (active at concentrations as low as 0.01-0.06 μm) with antimicrobial activity against several species. one of these, gageotetrin a is a very unique anionic amp that consists of only leucine and glutamic acid residues conjugated with a unique fatty acid, 3-hydroxy-11-methyltridecanoic acid. 48 another example is that of sonorensin from bacillus sonorensis, a broad-spectrum amp from the heterocycloanthracin subfamily, active against both gram-negative and gram-positive bacteria, including listeria monocytogenes and s. aureus. sonorensin displays an amino acid sequence with multiple copies of the same motif, making this peptide rather unique. 49 baceridin is a circular peptide from a plant-associated bacillus that is synthesized by ribosome-independent machinery and bears only six amino acids, 50% in the d configuration. 50 moreover, baceridin is a proteasome inhibitor, compromising cell cycle progression and inducing apoptosis in tumor cells by a p53-independent pathway. 50 copsin from coprinopsis cinerea is bactericidal against enterococcus faecium and l. monocytogenes by interacting with the peptidoglycan precursor lipid ii and interfering with the cell wall biosynthesis. 51 curiously, it is modified with a pyroglutamate, which confers a higher degree of thermal stability and resistance toward protease digestion. 51 even though some display fungicidal and virucidal properties, the chief activity of human amps is against gram-positive and gram-negative bacteria (figs. 1-3). furthermore, while amps represent an extremely diverse group of biological active molecules, most share common properties that contribute for their membranolytic or otherwise antimicrobial activity: positive charge, hydrophobicity, and amphiphilicity. therefore, the mechanism of action of most amps involves membrane disruption (fig. 4) , a process that is also required when their translocation is warranted and the respective targets are localized intracellularly. 39 the interaction of amps with bacterial membranes depends on the establishment of attractive electrostatic forces between these. bacterial species are known to carry negatively charged outer membranes due to phosphate groups of the lipopolysaccharides in gram-negative bacteria and to the lipoteichoic acids in gram-positive bacteria. 52 the fact that all gramnegative and gram-positive bacteria display these type of negatively charged lipids accounts for the lack of specificity of most abps, and promotes the attraction between amps and bacterial membranes while preventing their binding to most host cells membranes. moreover, the inherent hydrophobicity and amphiphilicity allow abps to form clusters at the membrane's surface once attached. 53, 54 at low concentrations (low peptide-to-lipid ratio), abps tend to adsorb onto the surface, adopting an orientation parallel to the membrane bilayer. however, clustering increases the peptide-to-lipid ratio, which subsequently promotes additional clustering. once a certain peptide-to-lipid ratio threshold is reached, abps adopt a perpendicular orientation relative to the bacterial membrane, which allows them to insert themselves into the membrane, 55 as will be further discussed (fig. 4) . peptides can adopt many different secondary structures and conformations, which depend on their amino acids sequence, as well as on the environment. consequently, different peptides and different environments favor the formation of unique structures, such as barrel staves, carpets, and toroidal pores. 40, 56, 57 when the peptides attach and are inserted into the membrane bilayer so that the hydrophobic regions align with the phospholipids' acyl groups and the hydrophilic regions create the central region of a pore, a barrel stave is formed. in addition, these structures act as a primer for the aggregation of new peptides, thus expanding the pore's diameter. 58 due to abps' cationic sites, membrane crossover would be very energetically unfavorable in their original parallel orientation. however, this orientation changes to a (1) cluster at the cell surface and cause membrane disruption by several different mechanisms (e.g., barrel staves, carpets, toroidal pores), (2) translocate into cells and impair intracellular organelle machineries, (3) impair protein-protein interactions, enzymatic cascades, and cytosolic signaling pathways, (4) interact with nucleic (not in the case of bacteria) acids, trap replication forks, and compromise nucleic acids as well as protein synthesis, (5) preclude several steps of viral replication, (6) inhibit genetic material trafficking, reverse transcriptase, and viral proteases, (7) block the interaction between virus and host cells (e.g., viral envelope glycoproteins gp120 and gp41 or coreceptor cxcr4), compromising virus binding and entry, and (8) cause membrane lysis on enveloped viruses. see text for detailed description. designed using servier medical art. perpendicular one upon abps' clustering, and the peptides are reoriented with their hydrophobic portions facing the membrane acyl groups and their cationic sites facing the interior of the pores. thus, clustering and pore formation provides a means for membrane disruption and the leakage of intracellular molecules from bacterial cells. 59 in contrast, if peptides remain parallel to the membrane surface with their hydrophobic residues facing the membrane while their hydrophilic residues face the surrounding milieu, a "carpet"-like structure is achieved. with such organization, membrane's rigidity weakens progressively as new peptides are added, culminating in its dissolution and breakup. mechanistically, this mode of action is less stringent because peptides do not need to adopt a specific structure. however, the necessary concentration of abps appears be much higher than that required for the formation of barrel staves. [60] [61] [62] for toroidal pores to form, peptides need to aggregate onto the membrane's surface and insert themselves in a perpendicular fashion. 63, 64 subsequently, abps are reoriented parallel to the membrane so that polar residues interact with the polar heads of the membrane lipids, thus causing membranes to bend. this induced bending of the bilayer causes the upper and lower leaflets to meet, and allows a mixture of peptides and lipid head groups to line with the interior of the pore, forming toroidal or wormhole structures. 60, 63, 65 abps may also inhibit bacterial growth and have a bactericidal effect by promoting the clustering of anionic lipids, such as phosphatidylglycerols (pgs) and cardiolipin. for instance, for ll-37, initially believed to act according to the "carpet" model, there is evidence that its fragments, namely kr-12, act as a magnet that competes for the negatively charged pgs, promoting their redistribution into "pg-rich domains." such phospholipidic reorganization may disturb cell signaling and compromise the activity of membrane-bound proteins, namely, the voltage-dependent potassium channels, which can seriously jeopardize bacteria survival. 34 likewise, n-acylated peptides derived from lactoferricin were shown to induce defects in e. coli cell division by rearranging the distribution of inner membrane phospholipids, essentially due to the clustering of cardiolipin and other anionic lipids. 66 the bias toward positive charges confers amps the ability to easily interact not only with biological membranes, but also with other negatively charged molecules (fig. 4) such as nucleic acids and those bearing phosphate groups. 39, 67 in addition, because this type of interaction is largely unspecific, amps can exhibit not only a broad-spectrum activity, but also multiple mechanisms of action (fig. 3) . 68, 69 for instance, lactoferricin is known to inhibit atp-dependent multidrug efflux pumps as well as dna, rna, and protein synthesis. 70 ten human amps derived from lactoferricin and lysozyme are thought (by sequence homology) to act by trapping the replication fork and preventing base recombination and dna repair. 71 furthermore, the presence of many prolines in some peptides (also known as ppii structures as aforementioned) hampers the organization of amphipathic structures. 72 these structures favor interactions between peptidic structures and between these and nucleic acids, thus playing a major role in signal transduction and complexes assembly. 73 however, ppii structures do not necessarily contain prolines, 74 and abps rich in arginine residues are also able to translocate across membranes and to interact with nucleic acids and proteins. hence, both proline and/or arginine-rich abps may be capable of inhibiting prosynthetic signaling pathways and enzymatic activity (fig. 4) , shifting the conformation of cellular structures and activating autolysins. however, this is a speculation that warrants further studying. in addition to targeting bacterial membranes, human defensins also bind to the peptidoglycan precursor lipid ii and inhibit cell wall biosynthetic enzymes in staphylococci species. 75 moreover, when stabilizing disulfide bridges between conserved cysteine residues in human amps with β-hairpin or β-sheet conformations are disrupted, the resulting linear peptides still maintain their antimicrobial properties despite losing membranolytic activity. 76, 77 the antifungal histatins act at multiple levels by mechanisms of action conserved across the histatin family of amps, with histatin 5 the most potent amp in this family. this amp binds the yeast transmembrane receptor heat-shock protein ssa1/2p, is internalized, and then targets primarily yeast mitochondria. 78, 79 by doing so, it leads to the formation of reactive oxygen species (ros), causes atp efflux, and inhibits oxidative phosphorylation. 80, 81 simultaneously, histatin 5 also interacts with the potassium transporter trk1p, causing release of k + ions and further atp efflux. 82 when the functional domain of histatin 5 was synthetically multiplied, its antifungal activities were significantly potentiated and it became significantly faster-acting compared to the normal histatin 5. 82 such an observation might prove itself very useful, because it indicates that modulating the number of functional domains per amp may enhance its antimicrobial activity without requiring the administration of increased quantities of amp. histatins may also exert their antimicrobial activities by inhibiting host and microorganismal proteolytic enzymes. histatin 5 is a strong inhibitor of human matrix metalloproteases 2/9 and metalloproteases from porphyromonas gingivalis. 83 thus, its inhibitory activity over proteolytic enzymes may attenuate tissue damage and microbial propagation during the onset of periodontal inflammatory disease. also, by inhibiting the cysteine protease clostripain from clostridium histolyticum, histatin 5 mitigates the virulence factors produced by this clostridium species and may therefore alleviate the complications associated with gas gangrene syndrome. 84 so far, the above-mentioned mechanisms of action have been discussed in the context of abps or antifungal peptides, and sometimes the same peptide is active against both bacteria and fungi. in turn, the action of antiviral peptides can diverge from these mechanisms and should thus be independently commented (fig. 4) , although some overlap does exist. extracellularly, most native antiviral peptides often present as α-helical structures, have primarily lytic activity on enveloped viruses, and can directly inactivate cell-free virions (fig. 4) . human lysozyme fragments are this group's prototype, capable of aggregating on the viral surface and causing disruption of membrane envelopes. 85, 86 similarly, cap37 peptide appears to exert its antiviral activity by destructing the virus envelope of type i herpes simplex virus (hsv) or even by disrupting the capsids of adenoviruses. 87 however, because membrane lipids of enveloped viruses derive from host cell membranes, special attention is required when considering the exploitation of this feature, as antiviral peptides may disrupt host cell membranes indiscriminately. alternatively, antiviral peptides may block the interaction between the virus and the host cell (fig. 4) . that is believed to be, at least in part, the mechanism of action of human defensins, θ -defensin, human α1-antitrypsin virip, cyclic lactoferricin, and serine protease inhibitor elafin. for instance, it has been demonstrated that all α-defensins [hnp-1, hnp-2, hnp-3, and hnp-4 and human α-defensin (hd)-5 and hd-6] and hbd-3 prevented hsv infection by blocking virus binding and entry. such antiviral activity was attributed to hnp-1-3, hd-5, and hbd-3's high affinity to hsv's glycoprotein b and hnp-4, hd-6, and hbd-3's avidity toward endogenous heparan sulfate. 88 similarly, protection against hiv is conferred by peptides with lectin properties that can bind viral envelope glycoproteins gp120 and gp41, crucial for viral attachment, fusion of envelopes with host membranes, and subsequent entry into host cells. 89 hnp-4 that binds and blocks the action of gp120, and θ -defensins (e.g., the pseudogene retrocyclin) together with the human α1-antitrypsin-derived 20-residue viral-inhibitory peptide both targeting gp41 represent examples of such peptides. [90] [91] [92] likewise, hsv-2 infection can also be blocked by retrocyclin, which binds tightly to glycoprotein b2. 93 the cyclic peptide lactoferricin seems to compete for the ligation to extracellular heparan sulfate or chondroitin sulfate, thus preventing the very first event in cytomegalovirus, hsv, and papillomavirus infection. [94] [95] [96] finally, elafin is thought to act indirectly in host cells by hampering viral attachment and probably by modulating host's antiviral and inflammatory responses toward hsv-2 infection. 97 synergistically with this mechanism, antiviral peptides can also bind and inhibit the activation of viral co-receptors, leading to further inhibition of glycoproteins-mediated viral attachment. not only that, hbd-2 and -3 inhibit viral infection by promoting the internalization of its co-receptor cxcr4. 98, 99 virucidal peptides may also preclude several steps of viral replication by interacting with intracellular targets (fig. 4) . this is the case of hnp-1 and hd-5, which may prevent hsv replication by binding directly to its dna. 88 also, hnp-1 arrests influenza virus replication by inhibiting protein kinase c phosphorylation, an essential step for nuclear trafficking events. 100 human cathelicidin (ll-37) derived peptides, in turn, inhibit reverse transcriptase and viral proteases, thus preventing integration of the viral genetic load into human dna. 101, 102 the few resistance mechanisms against amps demonstrated so far among microorganisms have been observed almost exclusively in bacteria. with very few exceptions, bacteria do not seem to develop complete resistance against cationic abps, though some strategies do exist among bacterial species for diminishing their potency and efficacy. the difficulty in acquiring resistance may stem mainly from the fact that abps target an essential cellular component for bacteria survival, which cannot be easily modulated by the cell without causing significant adverse effects. therefore, resistance mechanisms are not likely to be a limitation in the therapeutic utilization of abps. in light of this scarce resistance mechanisms de novo acquisition, what mechanisms do bacteria naturally develop/possess against abps? first, one should consider that the primary target of abps consists of bacterial cell membranes and bear in mind how abps depend on the electrostatic interactions between membrane negative charges and positive peptidic residues. accordingly, bacteria have learned how to modulate cell membrane charges and composition. gram-positive bacteria can partially modify the peptidoglycan's teichoic acid and gram-negative bacteria can partly change its lipopolysaccharide lipid a moiety, thus compromising this interaction. for instance, d-alanine-activating enzyme and d-alanine transfer protein are known to transport positively charged d-alanines to the surface anionic teichoic acids in gram-positive s. aureus, reducing the negative net charge of its outer membrane. 103 also in s. aureus, the five-component system graxsr-vrafg increases the expression of mprf and dltabcd genes upon exposure to cationic amps. when s. aureus strains are mutated so that the regulation of these genes is disturbed, these strains become more susceptible to daptomycin, polymyxin b, hnp, and platelet factor 4-derived peptide, and less infectious in vivo in a nonclinical endocarditis model. [104] [105] [106] the gene product mprf attaches lysine residues, which bear a positively charged ε-amino group, to the anionic phophatidylglycerols, making these less negatively charged and thus less susceptible to interactions with cationic amps. 105, 106 the gram-negative vibrio cholerae can increase its resistance to polymyxins more than 100-fold by modifying its lipopolysaccharides in a process mediated by almf. 107 the lpta gene product found in gonococcal species, such as the gram-negative bacteria neisseria gonorrhoeae, protects lipopolysaccharide lipid a moieties by attaching phosphoethanolamine, making these bacteria less susceptible to amps and increasing their capacity to modulate host's immune response by evading complement-mediated cellular death. 108, 109 moreover, in n. gonorrhoeae and neisseria meningitides, the presence of phosphoryl and phosphoethanolamine in lipid a moieties enhances the activation of the nf-κb pathway and the production of proinflammatory cytokines in human cells, which can amplify their virulence. 110 despite this modification-dependent virulence, the absence of such modifications in commensal neisseriae species allow these to colonize and coexist with the human host without inducing bactericidal host immune responses. 111 in addition, the adaptation of the composition and, hence, the electrostatic properties of the membrane in order to circumvent the host immune system is not an exclusive phenomenon of pathogenic bacteria. commensal bacteria of the intestinal tract can remove phosphate groups from their membrane's lipopolysaccharides, decreasing their negative charge and allowing greater survival and proliferation in the gut. 112 similarly to the above-mentioned paradoxical modification-dependent virulence, mutated commensal gut microbiota bacteroides that fail to remove phosphate groups from their lipopolysaccharides are killed during inflammation while normal strains keep their resilience. 112 therefore, there appears to be an inverse relationship between acquired resistance and bacterial virulence, so that induced/acquired modifications render cells less virulent while simultaneously allowing these to more easily colonize and coexist within the human host environment. second, bacteria are also able to adapt the fluidity of the membrane by increasing the hydrophobic interactions within their outer membrane, thus hindering pore formation. 113 third, bacteria can express proteases against abps or transporters and efflux pumps like atp-binding cassette (abc) transporters to circumvent such innate defense barriers. 114, 115 glu-c protease produced by s. aureus induces the loss of antibacterial activity of neuroendocrine peptides, and chromofungin, procatestatin, and human catestatin are enzymatically degraded when treated with bacterial supernatants. 116 in e. faecalis, bacitracin binds the abc transporter ef2050-2049, which interacts with the regulatory domain of the two-component system ef0926-27, increasing its expression and conferring resistance against bacitracin. 117 two-component systems regulate the expression of abc transporters and are constituted by a transport permease and a sensor kinase. however, at least in b. subtilis, the abc transporter itself is required for both sensing of and resistance to bacitracin, suggesting these transporters to also function as environmental sensors. 115 lastly, bacteria may also synthesize molecules capable of directly neutralizing abps, 118 which can provide a way for bacteria to bypass amps. however, such resistance mechanisms are very limited and resistance to amps does not take place to a large extent. r bastos et al. in humans, endogenous amps have been found in several fluids throughout the body, as depicted in figures 2 and 3 as well as in table i . as noted, multiple amps have been found in tears, saliva, milk, blood, urine, sweat (and others not-so-well-explored biofluids), reflecting not only a remarkable versatility but also a huge conservation that reinforces its essential role. the robust knowledge of amps on some fluids (e.g., tears, urine, saliva) over others (e.g., amniotic fluid, cerebrospinal fluid) most likely reflects their availability, but different exposure to pathogens from the environment (figs. 2 and 3) should also account for these discrepancies to a large extent. additionally, saliva and urine screening is of special interest, since both the oral cavity and the urinary tract represent the main doorways for microbial invasion and colonization, and are thus enriched with host defense peptides. likewise, milk screening is of high relevance due to the presence of particular proteins and amps that will boost neonate's immunity. despite underrepresented, amps from other fluids are equally relevant (figs. 2 and 3). for instance, amps collected from airway secretions, bronchoalveloar lavages, and nasopharyngeal aspirates can be valuable sources of information regarding the physiological response to pathogens of the respiratory tract and may, themselves, constitute raw models for new therapeutic drugs. also, other than circulating immune cells derived, blood has not been regarded as a rich source of amps, but this view can be questioned (figs. 2 and 3), most likely due to tissue-derived amps' passage to the blood circulation. however, it should be noted that human fluid reservoirs are not independent/isolated, and, consequently, peptides may be present throughout and cross between, possibly undergoing modifications between such reservoirs. amps may be present in fluids as a result of many different processes, including exocytosis, in situ proteolysis, tissue necrosis, and cellular lysis. therefore, in this section, we will characterize naturally occurring amps based on structural and functional similarities rather than their source of collection. defensins are cationic peptides rich in cysteine residues, presenting as β-sheet structures stabilized by disulfide bridges. 4 according to the alignment of these stabilizing disulfide bounds, mammalian defensins are classified into three subclasses, α-defensins, β-defensins, and θdefensins. disulfide bounds of α-defensins occur between cysteines 2-6, 1-4, and 3-5. these peptides consist of 29-35 amino acids and adopt a triple-stranded β-sheet conformation. human neutrophils express four distinct α-defensins, known as hnp-1 to hnp-4. despite having been initially isolated from peripheral blood leukocytes, hnp-1 to hnp-3 can also be found in bone marrow, spleen, and thymus. 119 the remaining two already identified human α-defensins, hd-5 and hd-6, are found only in paneth cells of the small intestine and in epithelial cells, thus being tissue specific. 120 expressed in the aforementioned cell types, amps can also be found in bodily fluids in direct contact with these cells. among the most recent discoveries, hd-6 has been found to be active against bifidobacterium adolescentis and other anaerobic gut commensals, but not (directly) bacteriostatic or bactericidal against most pathogenic bacteria, and may therefore play an important role in maintaining a balance among the microbiota of the gut. 121 similarly, human hd-5 is particularly potent against the gram-positive bacillus clostridium difficile, one of the most common pathogens responsible for nosocomial infections, whose highly virulent strains often attack small intestine mucosa. 122 in addition, α-defensins may show both cellular and regional specificity throughout the gastrointestinal tract, either secreted or active inside intracellular granules and constitutively expressed or amenable to induction. 15, 123, 124 it should also be emphasized that the activity spectrum of α-defensins is not limited to bacteria and fungi, exhibiting activity against several virus, including hiv, hsv, adenovirus, and human papillomavirus (hpv), and displaying several unique mechanisms of action (please refer to section 4). 4 it should be noted that the antimicrobial activity of α-defensins is influenced even by the difference in one amino acid, such as for hnp-1 to hnp-3. in fact, an additional acidic residue in hnp-3 lowers its effectiveness (most accurately, its potency) against s. aureus, p. aeruginosa, and e. coli. this is explained by the easily donated proton, which makes this defensin less positively charged (at least when considering interaction domains only), thus reinforcing the importance of a positive net charge for the antimicrobial activity of amps, 125, 126 as evidenced in section 4. in terms of disease, α-defensins are known to have a paramount role, particularly when the demands for defense mechanisms are increased. accordingly, a remarkable 15-to 25fold increase in the concentration of hnp-1 and hnp-2 (and hnp-3 to a smaller extent) in human tears as been reported after ocular surgery, an increase that allowed these peptides to reach the required concentrations for antimicrobial activity but that is followed by a decrease once healing has been completed and the demands for immune defenses have returned to baseline. 127 nonetheless, the goal of achieving this increased α-defensin concentration in tears is not restricted to the enhancement of the immune defenses, as it is also known to promote local cellular proliferation and tissue repair. 128 in parallel, salivary α-defensins are active against streptococcus mutans, but their secretion has been found deregulated in caries-positive human subjects. 129 in contrast, prolonged physical exercise has been shown to significantly increase the levels of salivary α-defensins, 130 showing that lifestyles may have a considerable impact on our amp-based defenses against microorganisms and it is possible to modulated the activity thereof. disulfide bounds of β-defensins occur between cysteines 1-5, 2-4, and 3-6. these defensins are longer than α-defensins, spanning from 36 to 50 amino acids, but also share a triple-stranded βsheet conformation. the first hbd was isolated from plasma samples and kidneys constitute the major source of hbd-1. 131 since then, peptides derived from human hbd-1 have been identified in tears, urine, vaginal lavage, sweat, and blood plasma, and these are effective primarily against e. coli. [131] [132] [133] [134] in turn, hbd-2 was isolated from psoriatic skin samples, 135 displaying bactericidal activity toward gram-negative e. coli, p. aeruginosa, and c. albicans, and bacteriostatic activity toward gram-positive s. aureus. despite very effective in vitro, both hbd-1 and hbd-2 present attenuated activities in vivo as a result of their sensitivity to physiological salinity. in contrast, hbd-3 is active against s. aureus and vancomycin-resistant e. faecium even at physiological salt concentrations. 136 the hbd-119 defensin has been found in seminal plasma, and it has been reported as potential efficacious against e. coli, s. aureus, and c. albicans. 137, 138 furthermore, hbd-114 has been identified in epididymal fluid and has been shown to regulate lipopolysaccharide-mediated inflammation toward e. coli, s. aureus, and c. albicans, protecting sperm from motility loss. 139 in disease conditions, increased concentrations of hbds in plasma and bronchoalveolar lavage fluid were reported in patients with diffuse panbronchiolitis. in particular, β-defensin 4a was suggested to play a role against p. aeruginosa. 140 also, while β-defensins are expressed throughout the gastrointestinal tract, these seem to have evolved together with changes in human gut bacteria, displaying characteristic expression patterns in response to certain microorganisms. their expression may be significantly altered in human diseases, most notably in inflammatory bowel diseases (for insightful reviews on this topic, please refer to 16, 141 and enhanced in inflammatory conditions of the ocular surface 134 ). with α-defensins, the role of the ph for amps' activity is considered. here, β-defensins serve to illustrate the role of salt concentration. in fact, tears contain a remarkable concentration of sodium chloride, which inhibits the activity of human amps (by ß40% in the case of hbd-2, an inhibition that increases up to 90% in the presence whole tear fluid, suggesting the presence of other inhibiting factors). 142 therefore, whenever there is an increase in the demand of amps activity, (e.g., upon infection or tissue damage), their concentrations must surge to reach the required protective levels. however, an excessive increase in the concentration of any amp may lead to tissue damage and local functions may be compromised. for this reason, a complex interplay of amps is required at surfaces like the ocular epithelia, which is achieved by a qualitative enrichment, in addition to the expected quantitative increase (for a depiction of the multitude of amps found in human tears, please refer to 143 ). similarly to α-defensins, the activity spectrum of β-defensins is not limited to bacteria and fungi, and they are active against several virus, namely, hiv, influenza a virus (iav), respiratory syncytial virus, and vaccinia virus, and display several unique mechanisms of action, depending on their target (see above section on mechanisms of action). 4 lastly, genomic studies have predicted additional β-defensins to be expressed in human cells, but their presence in human bodily fluids and their antimicrobial activity in vivo is yet to be demonstrated. 144 while αand β-defensins adopt triple-stranded β-sheet conformations, θ -defensins have shorter sequences and adopt a complete circular conformation, with stabilizing disulfide bounds between cysteines 1-6, 2-5, and 3-4. the peptide rhesus θ -defensin 1 is the prototype of this more recently discovered family of amps. like αand β-defensins, θ -defensins possess broadspectrum microbial activity against bacteria and fungi, while also being capable of protecting mononuclear cells from infection by hiv-1. 145, 146 moreover, these peptides display antiviral activity against hsv, hiv, iav, and severe acute respiratory syndrome (sars) coronavirus, acting by several mechanisms, depending on their target. 4 structurally, θ -defensin peptides are very interesting and very odd, representing the first cyclic peptide family discovered in animals, albeit not in humans. moreover, their circular structure appears to be required for antimicrobial activity. 145 these peptides were first isolated as antimicrobial octadecapeptides expressed in leukocytes of rhesus monkeys, and their formation results from the head-to-tail joining of two independent nine-amino acid peptides derived from truncated pro-α-defensins. 146 in contrast to the previously described classes of defensins, human θ -defensins are thought to be completely inactivated, despite the existence of mrnas encoding at least two θ -defensins expressed in the bone marrow. 145 while genes encoding θ -defensins in humans also encode premature stop codons (thus hampering θ -defensin expression), synthetic human θ -defensins (called retrocyclins) have been shown as promising antiviral agents. 147 in fact, retrocyclin-1 inhibits the entry of hiv, hsv, and iav into host cells. in other mammals, retrocyclin-1 also protects from infection by bacillus anthracis spores and the rhesus θ -defensin 1 protects mice from sars coronavirus infection. 147 cathelicidins are a very diverse group of cationic α-helical and amphipathic amps that exhibit a broad-spectrum activity against bacteria, fungi, and virus. 54 the term "cathelicidin" originally referred only to the entire precursor protein, though currently is commonly used for the whole family, including the resulting peptides with antimicrobial activity. in contrast to the mammalian trend in which cathelicidins and defensins are the main amps, there is only one human gene encoding multiple cathelicidin-related peptides, 144, 148 located on chromosome 3 and expressed in the airways, mouth, tongue, esophagus, epididymis, and small intestine. 149, 150 despite this tissue expression pattern, ll-37 is constitutively formed in spleen, liver, stomach, intestine, and bone marrow. ll-37 is highly positively charged (+6 charge at physiological ph 7.4), due to the high content of arginine and lysine amino acids, and adopts an α-helical structure in solutions with ionic composition similar to that of human plasma. 151 while defensins share common structural features, cathelicidin-related peptides are highly heterogeneous despite deriving from the same precursor. cathelicidins are characterized by a highly conserved n-terminal signal peptide (the so-called "cathelin domain") and a highly variable c-terminal antimicrobial domain that can be released after cleavage by proteinases. 148, 152 cathelicidin is cleaved into the antimicrobial peptide ll-37 by both kallikrein 5 and kallikrein 7 serine proteases, it is upregulated by vitamin d, and has been shown to significantly reduce the risk of death from infection dialysis patients. 153 ll-37 was shown to disrupt bacterial membranes through the formation of toroidal pores and carpet structures, 63 and to exhibit chemotactic properties, attracting leukocytes and activating secretion of chemokines. in addition, ll-37 is internalized by cells, acidified in endosomes, and activates the signaling pathway downstream to toll-like receptor 3 by interacting with double-stranded rna. 154 profiling of airway fluids collected from premature infants' tracheal aspirates during infection evidenced the production of ll-37 even at an early stage of development. 155 in these samples, ll-37 was found in significantly increased concentrations during pulmonary or systemic infections, suggesting this peptide to be as important to avoid infectious processes as to fight already established infections. 155 the concentration of ll-37 has been measured in seminal plasma samples from healthy donors and found to be up to 70-fold higher than in blood plasma. 149 furthermore, it was found to be attached to spermatozoa, eliciting a possible role in human fertilization or its precursor to be extensively cleaved by the high concentration of serine proteases present in seminal plasma. 149 ll-38, an alternative form of human cathelicidin peptides, contains one more alanine at the n-terminus than ll-37 and was initially found to be produced in female vaginal secretions due to the action of gastricsin on sperm precursor cathelicidin. 156 both ll-37 and ll-38 are active against bacteria such as e. coli, s. aureus, p. aeruginosa, and bacillus megaterium, and synergistically with peptides from seminal plasma play an essential defense role protecting the human reproductive system. 156, 157 interestingly, both citrullination and adp (adenosine diphosphate)-ribosylation of arginines can compromise the ability of ll-37 to prevent endotoxin-induced sepsis, perhaps because the attachment of these negatively charged molecules reduces the peptide's cationicity or by raising steric hindrance. 158, 159 histatins are a normal component of human saliva and part of the innate immune system, protecting against a broad array of infectious agents, especially against candida species, saccharomyces cerevisiae, cryptococcus neoformans, and neurospora crassa. [160] [161] [162] there are only two genes enconding histatins (both located on chromosome 4), and they are exclusively expressed in human salivary glands. 163 however, other active amps resulting from the cleavage of histatins 1 and 3 also exist. 164 histatins 1 and 3 are encoded by genes htn1 and htn3, respectively. 165 histatins 2, 4, and 5-12 are the products of posttranslational proteolytic cleavage of histatins 1 and 3, though histatin 5 can also result from posttranscriptional modification of histatin 3 mrna. 165, 166 peptides derived from histatin 1 bear distinct domains associated with specific functions, namely an n-terminal domain with antimicrobial activity and a c-terminal domain with wound-healing properties. 167, 168 histatin 5 has two important metal-binding motifs, consisting of an amino-terminal copper (ii)/nickel (ii)-binding motif and a zinc (ii)-binding motif, although they can also bind to cobalt (ii) ions. 169, 170 the ability to coordinate metal ions appears to be important for the stabilization of the secondary structure, particularly in the presence of negatively charged membranes. 170 nevertheless, histatins lack any defined secondary structure and are unordered when in aqueous solutions, assuming α-helical structures only in organic solutions. 171, 172 in addition, histatin 5 binding to copper (ii) and nickel (ii) ions induces the formation of ros, which contributes for its fungicidal activity. 80, 169 histatins can bind to a receptor on fungal cell membranes and induce cell death by disrupting the cell cycle and causing nonlytic loss of atp, as discussed above. 173 while histatins are effective, potent, and fast-acting amps against several antimicrobial species, these peptides are nontoxic to human cells and human microflora, which may be due to the fact that their translocation across the membrane is site and species specific. 78, 174 both parotid, submandibular, and sublingual glands secret histatins, and their concentration and secretion have been shown to decrease with age, even when accounted for total protein concentration. 175 moreover, oral candidal infections increase with age, suggesting a link between age-associated deficiency of human histatins and an increased risk of oral infections. 175 dermcidins are broad-spectrum anionic amps with no apparent homology to other known amps. peptides in this group comprise 110 amino acid residues, which are subsequently processed into smaller but still active ones. dermcidins are constitutively expressed in human eccrine sweat glands and secreted in sweat, exhibiting antimicrobial activity against common human pathogenic microorganisms such as s. aureus, staphylococcus epidermidis, e. coli, e. faecalis, and c. albicans. [176] [177] [178] this constitutive production contrasts with human defensins and cathelicidins, which are induced during inflammatory and stressful conditions. a small percentage of human breast cancer cells displays rna encoding dermcidin, and after oxidative stress induction different types of tumor cells leads to the production of diverse and biologically active proteolytically processed dermcidin peptides. 179, 180 therefore, the upregulation of dermicidins may confer human breast cancer cells a selective advantage compared to nonmalignant cells. in contrast, reduced expression of dermcidins in sweat from atopic dermatitis patients contributes to skin infections and altered skin colonization. 181 hence, the downregulation of dermicidins in atopic dermatitis patients may represents a suppression of an innate and fundamental defense mechanism, which, in turn, could confer an advantage to infectious microorganisms. unlike histatins, which are nontoxic to human cells and human microflora (see above), dermicidins can have serious deleterious consequences to the human host. dermcidin isoform 2 is known as a stress-induced oxidative protein capable of inhibiting the synthesis of nitric oxide in endothelial cells, insulin in pancreatic islet β-cells, and hepatic hormone synthesis. 182 also, hypertensive patients show significantly higher levels of plasma dermcidin, but salicylic acid has been shown to reduce dermcidin levels while simultaneously attenuating dermcidin-mediated insulin inhibition in patients with acute myocardial infarction. 183 therefore, the exploitation of dermcidin isoform 2 for antimicrobial therapeutic purposes is most likely not possible due to severe side effects. despite this, it may be a promising therapeutic target for hypertension and diabetes management. in animal models, dermcidin has been shown to induce platelet aggregation and coronary artery disease by activating platelet cyclooxygenase and inhibiting the constitutive form of nitric oxide synthase, respectively, with an efficiency 40 times higher than that of adp at activating cyclooxygenase. 182 notably, dermcidin was able to stimulate the development of coronary artery disease in one animal model, even at suboptimal concentrations of adp within 30 min. 183 together, these observations suggest that the ability of amps to fight infections depends on their induction by infectious microorganisms, the particular peptides generated, and the local environment/tissue in which they act. also, biological roles performed by human amps are more diverse than immediately expected, playing essential functions other than fighting infectious microorganism(s). in fact, dermcidin-mediated inhibition of insulin is unique in the sense that no other protein is known to arrest pancreatic insulin synthesis in such way, and similar observations might result in novel and unexpected applications of human amps. amps expressed by human liver (leap 1 and 2) were initially discovered in human blood, and subsequently found in urine. these peptides are known as hepcidins and are characterized by a high content in cysteine residues (approximately 32% of all residues, with eight disulfide bounds). 184 leap-1 or hepcidin-25 is essential for maintaining iron homeostasis, and, when mutated, leads to severe iron overload and juvenile hemochromatosis. 185 hepcidins are the main regulators of plasma iron concentration and its secretion is promoted during inflammatory responses, particularly by the action of interleukin 6, which is one of the main mediators of the acute phase response. 186 as iron bioavailability is a limiting factor for bacterial growth, hepcidins represent an organic mechanism for sequestering iron from invasive pathogens. however, when several iron sources are available, as it happens within the human host, eliminating a single reservoir may not be sufficient to attenuate microorganisms' virulence. moreover, bacteria are known to exploit almost every host iron-binding protein and reservoir and, consequently, human laeps/hepcidins are a rather limited source of antimicrobial activity. 187 for these reasons, the antimicrobial role of iron sequestration depends not only on hepcidins, but also on several other mediators, such as transferrin, lactoferrin, ceruloplasmin, haptoglobin, and hemopexin. mutations responsible for decreasing the levels of hepcidins or compromising the function of other regulators of iron homeostasis, such as the major histocompatibility complex class i like hereditary hemochromatosis protein (hfe), transferrin receptor 2, and ferroportin, lead to increased iron blood levels. when levels are high enough to produce hemochromatosis, individuals are at an increased risk of infectious complications, including bacteremia and meningitis caused by e. coli, 188 bacteremic cellulitis, and hemorrhagic bullous skin lesions caused by v. cholera, 189 multiple pyogenic abscesses in the liver parenchyma as a result of yersinia enterocolitica infection, 190 meningitis, endocarditis, and pericarditis resulting from infection with l. monocytogenes, 191 and fatal septicemia during infection with vibrio vulnificus. 192 in contrast, hemochromatosis can also be associated with decreased macrophage iron storages in the case of hfe-associated hemochromatosis. this depletion makes these cells more efficient in fighting salmonella enterica subsp. enterica, serovar typhimurium, and mycobacterium tuberculosis infections. 193, 194 however, these protective effects of macrophages iron storage depletion have only been demonstrated in animal models and appear to be mediated not by hepcidins, but rather by lipocalin-2, which reduces the availability of iron for salmonella, and transferrin and lactoferrin, both of which compromise iron acquisition by m. tuberculosis. 193, 194 neuropeptides and neuroendocrine peptides may exert mitogenic actions through which innate barriers are reinforced and may display neurotransmitter, immunoregulatory, and direct antimicrobial activity. vasostatin-1 was the first natural antifungal n-terminal chromogranin a derived fragment peptide, having been first isolated from chromaffin secretory granules from bovine adrenal medulla. 195 however, its sequence is highly conserved in humans (97% identity homology) and its microbial activity also overlaps, to some extent, with that of bovine origin. 196 irrespectively, human vasostatin-1 displays antimicrobial activities against gram-positive bacteria (micrococcus luteus, b. megaterium) and a large variety of filamentous fungi (n. crassa, aspergillus fumigatus, alternaria brassicola, nectria haematococca, fusarium culmorum, fusarium oxysporum, trichophyton mentagrophytes) and yeast cells (s. cerevisiae, c. albicans). 195 moreover, many autocrine and paracrine biological activities of chromogranin a, its precursor protein, have been attributed to peptides located along its sequence, which are co-released with catecholamines by chromaffin cells upon stimulation and can be found in human bodily fluids. 197, 198 therefore, the antimicrobial activity spectrum of vasostatin-1 may be extended by that of co-released peptides also formed by chromogranin a proteolytic cleavage, and some of the coproduced peptides are even more potent than vasostatin-1 itself. 195 in addition to the structural requirements for the antimicrobial activity of chromogranin a derived peptides, posttranslational modifications may also modulate their activity. for instance, s-pyridylethylation (an alkylating modification consisting of the addition of pyridylethyl moieties to the -sh functional groups of cysteine residues that disrupts disulfide bridges) renders it selectively active against b. megaterium but not m. luteus, while oxidation seems to render it inactive against bacteria but still active against fungi. in addition, chromogranin a derived peptides also undergo phosphorylation and glycosylation, which can modulate their physicochemical properties. 195 currently, vasostatin-1 is known to be stored in endocrine, neuroendocrine, and neuronal cells, and to be released from stimulated chromaffin and immune cells upon stress. moreover, the stimulation of polymorphonuclear immune cells induces the processing of chromogranin a and the secretion of vasostatin-1 and other chromogranin a derived peptides, 195 which may account for local inflammation. lastly, recombinant and synthetic human vasostatinderived fragments have been shown to inhibit vascular contraction induced by endothelin-1, parathyroid hormonal secretion, neuronal survival, expression of neurofilaments, and neuronal gaba uptake. 199, 200 adrenomedullin was first isolated from a human adrenal pheochromocytoma and its plasma concentration is raised under specific physiological conditions, namely, renal failure, 201 hypertension, 202 and sepsis. 203 this peptide has antibacterial activity against several grampositive and gram-negative bacteria, including propionibacterium acnes, s. aureus, m. luteus, p. gingivalis, actinomyces naeslundii, s. mutans, c. albicans, eikenella corrodens, actinobacillus actinomycetemcomitans, streptococcus pneumoniae, haemophilus influenzae, streptococcus pyogenes, bacteroides fragilis, e. coli, and helicobacter pylori. 204 human neuropeptide y displays antimicrobial activity against bacteria and fungi, but truncated fragments are tenfold more potent than the intact precursor neuropeptide y, perhaps because the net charge of the fragments is more positive than that of the intact neuropeptide. 205 encephalins and their derived peptides may either enhance or inhibit the immune response and the corresponding circulating immune cells/mediators in both humans and animal models. 206, 207 as well as their subsequent antimicrobial effects, may thus take place indirectly in immune system modulation. simultaneously, antibacterial assays have revealed that peptide b/enkelytin (a c-terminal fragment of proenkephalin a) specifically targets gram-positive bacteria, including m. luteus, b. megaterium, m. luteus, and s. aureus, while having no effect over gram-negative bacteria. 208, 209 classically, proenkephalin a has been ascribed to the secretory granules from adrenal medullary chromaffin cells and various brain regions, such as the striatum and the pituitary, according to some animal studies. 210, 211 despite this, it has also been demonstrated to be expressed in and secreted by polymorphonuclear neutrophils (accounting for its particular enrichment in wound fluids), 208 t and b lymphocytes, macrophages, and mast cells. 212, 213 however, it should be noted that the antimicrobial effects of encephalins and their derived peptides result mostly from animal studies and have not been adequately studied in human secretions, despite the high conservation of their sequences across species, which most likely contribute for the similar activity spectrum. even so, phosphorylation and glycosylation are characteristic of these peptides, 208, 214 and it is possible to envision that differences at the level of posttranslational modifications or as a result of gene divergence may result in distinct activity spectra. interestingly, peptide b/enkelytin is metabolized in vivo to opioid peptides, thus revealing an intricate relationship between innate immunity and pain modulation, and its plasma concentration is increased after coronary artery bypass grafting in humans. 215 because it is expressed in both immune and neuronal cells, it is possible that the same stimuli may act on both cells populations, thereby accounting for immune system modulation at the periphery and alterations in central nervous system signaling. however, the exact roles and mechanisms of this interplay are not clear. in addition, other amps found in epithelial secretions from the gut and the skin, for example, include peptides derived from alpha-melanocyte-stimulating hormone, which is active against s. aureus and c. albicans. 216 accordingly, evidences suggest that amps like these act by inhibiting mrna and protein synthesis rather than inducing direct membrane disruption, as is the case for most amps. 217 several cationic proteins display nonenzymatic antimicrobial activity, which is sustained by the resulting cleavage peptides after protein fragmentation. for example, lactoferrin is a glycoprotein enriched in milk and neutrophilic granules, which has the ability to sequester iron and thus prevent bacterial overgrowth. 218 when digested by pepsin, lactoferrin yields lactoferricin h (human), an amp able to neutralize bacterial toxins, regulate gene transcription, inhibit complement activation, viral infection, and tumor overgrowth, thus further extending the antimicrobial properties of its precursor. 76 human chemokines are secreted by macrophages and polymorphonuclear immune cells and, therefore, found in the blood circulation. 219 moreover, during allergic inflammatory responses to bacterial infections of the airways, the eosinophil-recruiting chemokines eotaxin-1/ccl11, eotaxin-2/ccl24, and eotaxin-3/ccl26 are generated by mast cell proteases, active against several airway pathogens, including s. pneumoniae, s. aureus, h. aeruginosa. 220 peptides resulting from the cleavage of pepsinogen a and c prosequences have also been shown to exert antimicrobial activity. although these were initially identified from the stomach of bullfrogs, synthesized human pepsinogen c prosequences with similar structural characteristics (amphipathic and helical structures) to these cleavage peptides have also exhibited antimicrobial activity. 221 calcitermin is an amp that results from the cleavage of a 15 amino acids long sequence from the c-terminal region of protein calgranulin c, isolated from human airway secretions. 222 by adopting an alpha-helical conformation in bacterial membranes, calcitermin is able to target gram-negative bacteria (e.g., e. coli and p. aeruginosa) and fungi (e.g., c. albicans). 222 furthermore, the precursor protein and fragment peptide may act synergistically to protect the human host against foreign microorganisms present in the airways. on the one hand, the cleavage peptide calcitermin inserts into membranes of microorganisms. on the other hand, the precursor protein calgranulin c has a proinflammatory activity. by acting as a dangerassociated molecular pattern molecule and binding to the receptor for advanced glycation end products in innate immune cells, it activates the map-kinase and nf-κb signaling pathways, leading to the production of proinflammatory cytokines and histamine, upregulation of cell adhesion molecules, recruitment of leukocytes, and degranulation of granulocytes. 223, 224 dermcidin-derived peptides such as dcds, ssls, and leks (the letters correspond to the first three amino acids of the corresponding precursor dermcidin protein) are also formed in eccrine sweat glands (but not in apocrine sweat glands) at these body sites with high probability for contact with pathogens (e.g., palms, face, arms) and exhibit antimicrobial activity against a large number of microorganisms, including s. aureus, e. faecalis, e. coli, s. epidermidis, pseudomonas putida, methicillin-resistant s. aureus, and rifampicin/isoniazid-resistant m. tuberculosis. [176] [177] [178] such dermcidin-derived amps are regulated by proteolytic processing at several levels (see section 2) and are differentially expressed during inflammatory conditions. 225 these peptides are resistant to proteolytic degradation in sweat up to at least 40 hr and, interestingly, most dermcidin-derived peptides are anionic in nature. if such distinct properties may lead to different antimicrobial activity spectrum is unclear, though not surprising, as skin represents a harsh and particularly unique environment. as of specific interest, it should be noted that the consensual average skin surface ph has been decreasing in the last few years and is now generally accepted to be below 5. while showering and cosmetic products decrease skin's surface ph, plain tap water can increase the skin ph up to 6 hr. 226 noticeably, negative charges seem to be important for dermcidin-derived peptides' antimicrobial activity, in contrast with what would be expected for amps. in fact, most dermcidin-derived peptides are naturally anionic, but low ph (high h + concentration) leads to an increase in their net charge (toward positivity). therefore, while an acidic skin actually keeps the resident bacterial flora attached to it, a more alkaline skin compromises such attachment, suggesting that the more negatively charged such skin peptides are (alkaline skin), the more efficient these become. 226 despite the average length of 32.76 residues and net charge of +3.21 for the close to 3000 amps already identified, human amps tend to be longer and more positively charged. amps with more than 100 amino acids have been identified across the six kingdoms of life. curiously, most (approximately half) appear to be of human origin, presenting as amino acid sequences of 127 residues on average and suggesting large amps to be a human feature. moreover, compared to all the remaining amps, large human amps tend to be biased toward leucine (8.2%) and lysine (10.5%) residues, displaying nonpolar aliphatic and positively charged side groups, respectively (table i) . therefore, large human amps are enriched with amino acids that promote distinguishing features of amps: high overall positive charge, hydrophobicity domains, and amphiphilicity. nevertheless, this bias toward lysine residues is neither unique to human amps nor more pronounced among these. for instance, the amphibian cathelicidin rc-1 is composed by 32% lysine residues, and its homologous snake crotalicidin contains 38% lysine residues, showing high potency against s. pyogenes, acinetobacter baumannii, e. faecalis, s. aureus, e. coli, klebsiella pneumoniae, and p. aeruginosa. 227 as evidenced in table i , large human amps have been found in a variety of bodily fluids, including tears, saliva, urine, airways secretions, breast milk, blood, sweat, and epididymal fluids. in addition, other large amps are also expected to exist despite not constitutively found in biologic fluids, due to their inducible nature. for instance, paneth cells in the small intestine release amps-rich granules upon stimulation by cholinergic or bacterial stimuli, 228 and granulocytes are known to contain amps in granules destined for extracellular secretion. 229, 230 therefore, as the synthesis and secretion of large amps may not be constitutive but amenable to induction by microbial macromolecules and inflammatory cytokine stimuli, several other large amps may yet to be catalogued. hence, exploration of novel large antimicrobial human peptides is an ongoing work that may yield novel therapeutic agents. peptidomics is the complete study or global analysis of the peptides present in a biological sample, at a given time, under a particular condition. 231, 232 the identification of naturally occurring amps in human biological fluids is a laborious, daunting, and sometimes unsuccessful task. such naturally occurring peptides can directly result from gene encoding, from passage to bodily fluids as a result of cellular damage and renewal, or from extracellular proteolytic processing of precursor proteins. the latter, considered to be the most prevalent, hampers the identification and interpretation of biologically active amps because precursor proteins may themselves display antimicrobial activity, but may also be cleaved into multiple functional and nonfunctional peptides. 233, 234 moreover, owing to the large dependency of amps on their sequence and 3d structure, these peptides should not be subject to mass spectrometry (ms) based approaches employing enzymatic or chemical digestion, neither to any in vitro step that may cause their fragmentation. instead, top-down proteomic strategies are preferred. classically, different peptides fractions have been separated and tested for their biological activity, often without ever addressing the peptides' biological/antimicrobial activity, their sequence, target, or hypothetical mechanism(s) of action. however, current strategies are more focused, precise, and informative, capable of addressing all these parameters, sometimes in a single study (see below). 129, 235, 236 human biological fluids consist of complex samples, containing lipids, salts, proteins, carbohydrates, and other molecules that make the study of endogenous peptides extremely difficult. consequently, enrichment and separation steps are almost always required. of these biomolecules, proteins and larger peptides as well as salts are the most complicated to separate from the target peptides. luckily, salts can sometimes be removed in the same procedures applied for protein removal. first and foremost, proteases/peptidases have to be inactivated, which can be done by denaturing procedures (e.g., microwaving, boiling) or by adding protease/peptidase inhibitors. 237, 238 however, both of these can modify the peptide structure and, thus, these steps can be avoided when samples are resistant enough to further protease/peptidase activity. this is the case for urine samples, for example, as, when collected, have long been subject to proteolytic processing in the bladder. proteins are frequently removed by selective precipitation, most commonly by organic solvent (e.g., acetone) or acidic (e.g., trichloroacetic acid) precipitation, which also removes salts (left in the supernatant). 236, 239 however, precipitation-based proteins removal is not complete and may lead to the formation of peptide aggregates, which are consequently lost in the precipitate. 240 since peptides can present a great variety of sizes, sequences, structures, hydrophobicity properties, net charges, and other characteristics, their isolation is complex. still, such complexity allows for isolation steps to take place at multiple dimensions, increasing peptides isolation efficiency and accuracy. for instance, peptides can first be isolated based on their size and charge, 241, 242 bias toward specific amino acids (e.g., cysteines, tryptophans, methionines), [243] [244] [245] or on the presence of post-translational modifications (ptms) (e.g., phosphopeptides, glycopeptides). 246, 247 still, because of the aforementioned limitations, the search for endogenous amps in human bodily fluids has mostly relied on the identification of candidate amps by chromatographic techniques (e.g., high-performance liquid chromatography, hplc) and sequencing (e.g., edman sequencing), followed by their de novo chemical synthesis and in vitro antimicrobial activity testing. for these reasons, the identification and in vivo testing of novel amps is often time consuming and requires multiple studies/phases and resources. in order to mitigate this problem, candidate human amps have come to be first predicted in multiple ways, including mining of the entire human genome for particular motifs known to confer antimicrobial activity, and screening of human peptidomes (e.g., salivary, urinary) in order to find homologous peptides to other known amps. accordingly, several libraries and databases are currently available for data comparison, and some search programs can even combine both previously obtained data and de novo information. 248 even so, the identification of amps benefits the most from combinations of chromatographic and immunological techniques, genomics and proteomics. while genomics and proteomics both allow the prediction of novel amps and have the potential for contributing with a larger number of putative amps, peptides with proven in vivo antimicrobial activity have to be more accurately identified by combinations of chromatographic and immunological techniques, chemical sequencing and antimicrobial assays. though immunoassays can detect the intended target in a variety of complex biological samples, these techniques do not provide an integrative view of the peptidome, can suffer from cross-reactivity or lack of specificity issues and require previous knowledge of the target structure. 249, 250 moreover, this issue becomes a particular problem when considering that shorter or longer peptides resulting from the same precursor protein may all contain the same epitopes and thus be recognized as the same peptide fragment despite exhibiting distinct biological activities. electrospray ionization (esi) 236 and matrix-assisted laser desorption ionization (maldi) 251 have been the most frequently and successfully applied ionization techniques in the field of bodily fluids peptidomics. in line with these, peptides are most frequently previously separated by lc-based 251 and capillary electrophoresis (ce) based approaches, allowing different peptide fractions to be independently separated. 252 from this point onwards, almost any mass analyzer can be used, although in practice quadrupole time-of-flight (q-tof) and ion traps (it) instruments are the most frequently utilized ones in peptidomics, especially in exploratory studies. [253] [254] [255] in turn, fourier transform-ion cyclotron resonance-ms is more suitable for targeted/confirmatory analysis when dealing with fewer peptides. 256 because these apparatuses allow tandem ms to be performed, peptides can be readily sequenced in addition to their identification, circumventing the above-mentioned limitations concerning immunological assays and largely simplifying peptidomics workflows. in summary, when aiming at the isolation of a particular peptide, with predicted or known charge and molecular weight, an ms-based procedure can theoretically be very straightforward. first, fluid samples require (sometimes multiple) centrifugation steps to remove cells, cellular debris, wastes, and possible contaminants. then, proteins and peptides in the supernatant are separated and fractionated by multidimensional chromatographic techniques. within these procedures, proteins and peptides can be initially fractionated by gel filtration (size dimension), followed by cation-exchange (charge dimension) fractionation. cation-exchange chromatography uses a negatively charged ion exchange resin with affinity for molecules with net positive charge. a salt gradient is used to separate the peptides of interest from other bound peptides, based on their predicted isoelectric point. finally, peptides can be subject to ms analysis. they are typically ionized by esi or maldi and subsequently analyzed in a q-tof, it, or hybrid ltq. as amps tend to be highly basic peptides due to a bias toward arginine and lysine residues, these have a propensity to be particularly enriched when applying cation exchange chromatography based techniques. 257 however, because biological fluids are complex matrices, these sometimes require multiple fractionation, isolation, and extraction steps. these are laborious optimization techniques for the detection and quantification of amps and, despite their inherent complexity, they are often based in not always accurate functional and structural predictions. a recent approach has proved itself capable for the isolation of peptides present in bodily fluids that can bind directly to certain bacterial membrane components, such as lipopolysaccharide, and induce an inflammatory response against these. 129, 235 after obtaining a bacterial homogenate and extracting membrane components with an organic solvent such as n-butanol, functionalized beads with n-hydroxysuccinimidyl-sepharose (an agarose used in affinity and protein chromatography) are conjugated with these membrane bacterial components and incubated with a human biological fluid (e.g., saliva, urine). then, peptides bound to the conjugated beads are eluted and analyzed in a ltq-orbitrap hybrid fourier transform apparatus. moreover, functionalized beads conjugated with bacterial membrane components can be tested in vivo for their capacity to induce the production of inflammatory mediators. thus, this exploratory approach could result in the identification of potential human amps with selective properties capable of binding bacterial membranes and inducing an inflammatory response. recently, dallas and colleagues have attained the most complete and prolific analysis of naturally occurring peptides with potential antimicrobial activity in human milk by nano-lc quadrupole-tof tandem mass spectrometry (ms/ms), while searching against libraries of human milk peptides and known amps. 236 in order to remove milk peptides produced by in vitro proteolysis, fresh milk derived peptides were compared to control samples of the same origin but immediately subject to boiling. as boiling denatures proteases, in vitro proteolysis does not take place and peptides present in these controls could then be confidently assigned in the original analysis. moreover, masses fragmented in the first round of ms/ms were excluded from subsequent rounds of ms. 236 the authors realized that more than 80% of the +300 unique naturally occurring peptides identified with 99% confidence have yet unknown functions, which serves to illustrate how much there is still to discover regarding the biological roles of human endogenous peptides in biological fluids. nevertheless, the antimicrobial activity of the milk peptides (41 predicted amps) was confirmed in vivo by radial diffusion assays against the gram-negative e. coli and the gram-positive s. aureus. 236 furthermore, this study reinforced the observation that the background against which mass spectra are searched seems to be a more critical factor than the mass analyzer or the ionization technique used, when it comes to both the number of peptides identified and the confidence by which these can be assigned. in the same study, authors have emphasized and demonstrated the importance of avoiding in vitro hydrolysis of amps in human bodily fluids, which can be attained by adding protease inhibitors after sample collection or by adequately accounting for this phenomenon, as the authors did by using an appropriate control. in contrast, not all bodily fluids seem to be susceptible to this degree of hydrolysis, at least not to the same extent. urine, for instance, is thought to be more stable and not to require treatment with protease inhibitors. 258 however, by the time urine is collected it has already remained stagnant for considerably longer periods of time, and, hence, probably already extensively exposed to the action of proteases/peptidases inherently present in urine. therefore, how intact urinary amps actually are should always be questionable and these should ideally be interpreted considering the background of hydrolytic enzymes present in the same urine sample. also questionable is the inhibition of proteolysis in seminal plasma samples. in fact, the liquefaction process of human semen performed by seminin and other proteolytic enzymes is physiological, 259 and, therefore, naturally occurring amps should be analyzed in samples that were allowed to liquefy without the addition of protease inhibitors. curiously, seminin, which is the primary agent responsible for liquefaction of the seminal coagulum, is partially destroyed by freezing at −20°c, 259 reinforcing the vitality of analyzing fresh samples. similarly, the degradation of peptide fragments derived from semenogelins in seminal plasma samples is time dependent and responsible for the decline in hiv-enhancing activity of sperm, once again underscoring the importance of timely performing analyses of peptides in bodily fluids. 260 as previously stated, amps activity depends largely on their 3d structures, and their correct characterization becomes of paramount importance. the best experimental techniques have been and currently are x-ray crystallography 261 and nuclear magnetic resonance, 262 both of which allow for the study of structure-function relationships, though very expensive. therefore, currently, these are commonly replaced or complemented by bioinformatics prediction tools whenever possible. using such tools, the sequence of amino acids of a peptide allows for the accurate and immediate prediction of the presence of secondary structures (e.g., αhelices, β-sheets). then, the overall 3d structure is devised by algorithms employing energy minimization principles and molecular dynamics, sometimes resulting in multiple and not mutually exclusive 3d conformations, which is in accordance with peptides dynamic structure in biological fluids. 263, 264 the most common identification software referenced in the literature for peptide/precursor protein identification are sequest and mascot. 265, 266 currently, however, there is a considerable need for algorithms and software capable of correctly identifying amps and predicting their structure-function relationship. amps are a promising replacement for conventional antibiotics owing to their effectiveness against multiresistant bacteria and over multiple bacterial species simultaneously, invoking a diverse set of mechanisms that cannot be easily shortcut by bacteria, fungi, and/or virus. an ideal amp would be (i) highly selective against its target while leaving human host cells unaffected, (ii) not prone to resistance mechanisms, (iii) relatively easy to produce at low costs, and (iv) stable during storage or upon administration. drug design of such amps focuses on peptidic and nonpeptidic mimetic drugs, modulating the hydrophobicity, positivity, and amphiphilicity of endogenous amps to increase their antimicrobial potency. however, exploiting amps for therapeutic purposes is actually more complex than initially envisioned. while linear amps present a simpler design and a more predictable structure-function relationship, circular peptides may allow the design of longer acting and more resistant amps. such peptides have been designed by inserting the intended amp into other circular peptide (cyclotides) and have been proven efficacious against hiv and inflammatory diseases by circumventing their instability and poor bioavailability. 22, 267 similarly, while humans produce amps with l-amino acids and their antimicrobial activity may depend on the action of endogenous enzymes, which can only act upon l-type amino acids, producing amps with d-amino acids may render these more resistant to hydrolysis. rather than administering exogenous amps, it is possible and perhaps more secure and controllable to pharmacologically stimulate the production of endogenous amps. for instance, 1,25-dihydroxycalcypherol (active vitamin d3) has been successfully used to induce the expression of defb4 (defensin, beta 4) and camp (cationic antimicrobial peptide) genes, the production of both ll-37 and human β-defensin 2 in cell cultures of keratinocytes from diabetic foot ulcers and to promote wound healing. 268 accordingly, the persistence of functional milk human κ-caseinoglycopeptides in plasma of human infants after human milk feeding serves the purpose of exogenously administering amps without the requirement for their de novo synthesis. 269 amps can help preventing biofilm formation and microorganisms' growth. that is the case of ll-37 and its fragments, which were already shown to have antibiofilm formation properties against several methicillin-resistant s. aureus strains and p. aeruginosa, common pathogens of hospital-acquired infections, as well as against the melioidoisis' etiological agent burkholderia pseudomallei and the uropathogenic e. coli. [270] [271] [272] [273] another amp with antibiofilm formation activity is hbd-3, found to prevent the development of methicillin-resistant s. epidermidis and s. aureus biofilms, largely responsible for orthopedic implants associated infections. 274 likewise, amps may also inhibit the formation of fungal biofilms. for instance, histatin 5 has been demonstrated to successfully inhibit the growth of c. albicans biofilm on denture acrylic. 275 these examples may broaden the applications of amps in the clinical and biomedical fields by allowing functionalization of catheters. alternatively, implants and other medical devices can also reduce bacterial colonization, biofilm formation, and infection rates, presenting long lasting functionality, broad-spectrum activity, and minimal cytotoxicity against human cells. 276, 277 human amps could, theoretically, also be used as biosensors immobilized onto microchips for identification purposes, allowing the identification of microorganisms. however, such applications have only been exploited with animal or synthetic amps. these biosensors on electrical impedance alterations resulting from the presence of bacterial or fungal surface elements, or on the specificity of peptide nucleic acid probes against their targets, presenting higher versatility, lower costs, and lower sensitivity limits compared to other conventional methodologies. [278] [279] [280] alternatively, amps could be used as drug delivery systems in the form of conjugates in order to accurately target drugs and other agents to tumor sites or intended organs, as typified by monodisperse "endosomolytic" nanoparticles for in vivo gene delivery using intravenous injection, or by functionalized nanoparticles with higher membrane penetration targeted against gliomas. 281, 282 such functionalization may allow for deeper tissue penetration, increased antimicrobial potency, sustained release, and novel routes of administration to be achieved. ever since the isolation of the first peptide from the frog skin in 1983, 283 several breakthroughs were made in the isolation, synthesis, and application of amps. still, many challenges are yet to overcome in the field of amps peptidomics, 284 reflecting mainly their huge diversity and how little is known about their behavior in vivo and their structure-function relationships. in terms of costs, producing amps can be several hundred times more expensive than the production of conventional antibiotics. 285 moreover, amps' design can be very complex and the quest for the perfect amp a never-ending search. in fact, considering the possibility of working with only 20 amino acids, a small peptide with ten amino acids could have up to 20 10 = 1.02 × 10 13 different sequences, a larger peptide with 20 amino acids could present with up to 20 20 = 1.05 × 10 26 different sequences, and one with 100 amino acids could adopt any one of 20 100 = 1.27 × 10 130 different sequences. such possibilities do not even account for the presence of posttranslational modifications. then, each one of these peptides could shape into several different secondary structures and fall into a wide spectrum of activity, depending on the milieu conditions. furthermore, in a way to overcome the challenge of peptide stability, one has to consider the possibility to synthesize and to administer amps containing d-amino acids, thus decreasing their susceptibility to hydrolysis by human enzymes. 267 to deal with such large amount of amino acid combinations one should mind using peptide libraries and computational models (such as by quantitative structure-activity relationship analysis) in order to narrow large collections to few surrogate amps (for a review please see blondelle and lohner's paper. 286 another challenge to overcome is the lower amp's activity in vivo when compared to that observed in vitro. this has largely hampered the development of amps as therapeutic agents, as this decrease in activity stems from differences in ph and salt concentrations, the presence of proteases and corresponding inhibitors, and other interacting molecules hindering antimicrobial activity. accordingly, several amps (e.g., pexiganan, 287 iseganan, 288 neuprex 289 have reached phase ii clinical trials only to fail after approval for marketing because they did not evidence superior activity over already marketed conventional antibiotics. in early 2016, clinicaltrials.gov (a registry and result database of publicly and privately supported clinical studies of human participants conducted around the world) listed few clinical trials involving amps. for instance, ll37 is currently being studied for its efficacy in melanoma patients due to its ability to stimulate the immune system, while c16g2 and chromogranin a derived peptides are under scrutiny for their therapeutic potential against dental diseases. simultaneously, therapeutic strategies are also being studied to augment amps' expression in amp-deficient patients. this deficiency is believed to be due to an increase in th2 lymphocytes derived cytokines, il-4, il-13, and il-10, and a decrease in tnf-α, il-6, il-1, and interferonγ . one example of such strategy is pimecrolimus, a calcineurin inhibitor that binds with high affinity to macrophilin-12, preventing the translocation of nuclear factor of activated t cells to the nucleus and the transcription and release of such inhibitory cytokines (for more up-to-date trials, readers can access clinicaltrials.gov). another possible caveat concerns the cytotoxicity to mammalian cells when in concentrations above naturally occurring values. when bacteria produce amps, they also develop means to avoid their targeting by such peptides, such as efflux pumps and the sequestering of enzymes. however, eukaryotic cells are equally prone to damage if the administration of exogenous amps is carried out in high enough concentrations. therefore, administering amps not constitutively produced or at concentrations above those normally found in the human host environment can be toxic and very detrimental to human cells. furthermore, rapid metabolism and low bioavailability are characteristic of amps because these peptides can suffer extensive proteolysis in vivo, thereby accounting for their inactivation and short half-life. 22, 28, 290 similarly, for peptides to be available at sites distant from their origin, these would have to cross many cellular membranes. however, due to amps' polarity, membrane hydrophobicity may prevent them from doing so. 291 moreover, in contrast to other highly polar mediators (e.g., ionic salts and a few metabolites), endogenous peptides tend not to have a transporter, further compromising their bioavailability in different compartments and the subsequent impossibility to be absorbed through the gastrointestinal tract. therefore, the number of possibilities rapidly escalades, and each amp-based therapy can be further optimized based on the modulation of chemical properties and engineering of delivery systems. even acknowledging all these factors, the human host is most certainly an unpredictable environment and the same peptide may behave differently, displaying unique individual pharmacokinetics and pharmacodynamics. on a final note, due to amps' interaction with and dependence on other immune mediators, variability will most likely result from immune status alterations as those frequently found in human diseases, including infectious ones. taken together, the above discussed results support amps as constituting a paramount group of defense molecules in human biological fluids, being present in most fluids, contributing for the sterility of some of these, but being most notably enriched in biological fluids bathing tissues with the largest load of microorganisms (fig. 2) , such as saliva and urine. also, while some amps seem the display activity spectra against only a handful of microorganisms, others display broad-spectrum effects. thus, the expression and activity patterns of human amps enriched in biofluids may have suffered selective pressures resulting from exposers to microorganisms specifically present in each fluid (fig. 2) . this work was financed by national funding from fct (fundação para a ciência e a tecnologia) through the project uid/bim/04501/2013, uid/ic/00051/2013. rv thanks fct for if/00286/2015 fellowship. the authors report no declarations of interest. with saliva proteomics research. since then, he extended the application of proteomics to the characterization of other biofluids' proteome and peptidome in order to identify the biological pathways modulated by diseases such as diabetes mellitus and bladder cancer. currently, he works to a large extent with bioinformatics tools for the identification of enzymes involved in the regulation of proteome remodeling. additional supporting information may be found in the online version of this article at the publisher's web site: apd3: the antimicrobial peptide database as a tool for research and education anticancer efficacy of magainin2 and analogue peptides structure-activity analysis of thanatin, a 21-residue inducible insect defense peptide with sequence homology to frog skin antimicrobial peptides cationic host defence peptides: potential as antiviral therapeutics the n-and c-terminal fragments of ubiquitin are important for the antimicrobial 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realistic outlook optimization and high-throughput screening of antimicrobial peptides pexiganan acetate a multinational, randomized phase iii trial of iseganan hcl oral solution for reducing the severity of oral mucositis in patients receiving radiotherapy for head-and-neck malignancy prolyl peptidases: a serine protease subfamily with high potential for drug discovery bioavailability and transport of peptides and peptide drugs into the brain key: cord-274506-fzcuu4ma authors: jo, seri; kim, hyojin; kim, suwon; shin, dong hae; kim, mi‐sun title: characteristics of flavonoids as potent mers‐cov 3c‐like protease inhibitors date: 2019-09-12 journal: chem biol drug des doi: 10.1111/cbdd.13604 sha: doc_id: 274506 cord_uid: fzcuu4ma middle east respiratory syndrome‐coronavirus (mers‐cov) is a zoonotic virus transmitted between animals and human beings. it causes mers with high mortality rate. however, no vaccine or specific treatment is currently available. since antiviral activity of some flavonoids is known, we applied a flavonoid library to probe inhibitory compounds against mers‐cov 3c‐like protease (3clpro). herbacetin, isobavachalcone, quercetin 3‐β‐d‐glucoside and helichrysetin were found to block the enzymatic activity of mers‐cov 3clpro. the binding of the four flavonoids was also confirmed independently using a tryptophan‐based fluorescence method. the systematic comparison of the binding affinity of flavonoids made it possible to infer their scaffolds and functional groups required to bind with mers‐cov 3clpro. an induced‐fit docking analysis revealed that s1 and s2 sites play a role in interaction with flavonoids. the experimental and computational study showed that flavonol and chalcone are favourite scaffolds to bind with the catalytic site of mers‐cov 3clpro. it was also deduced that some flavonoid derivatives with hydrophobic or carbohydrate attached to their core structures have a good inhibitory effect. therefore, we suggest that flavonoids with these characteristics can be used as templates to develop potent mers‐cov 3clpro inhibitors. coronaviruses (covs) are a positive sense, single-stranded rna virus coated with viral particles (fehr & perlman, 2015) . together with arteriviridae and roniviridae, covs belong to the coronaviridae family in the order nidovirales. these covs can infect a wide variety of hosts, including avian, swine and humans. human coronaviruses (hcovs) represent a major group of covs associated with various respiratory diseases from common cold to serious pneumonia and bronchitis (mesel-lemoine et al., 2012) . today, hcovs are recognized as one of the most rapidly evolving viruses originated from their characteristic high genomic nucleotide substitution rates and recombination. in human, their infection is known to cause approximately one-third of common cold. severe acute respiratory syndrome (sars) and middle east respiratory syndrome (mers) covs are highly pathogenic and caused a fatal first major outbreak in 2003 and 2012 , respectively (de wit, doremalen, falzarano, & munster, 2016 . sars-and mers-covs genomes contain two open reading frames orf1a and orf1b translated to two respective viral polyproteins pp1a and pp1ab by host ribosomes. orf1a encodes two cysteine proteases, a papain-like protease (plpro) and a 3c-like protease (3clpro). while plpro cuts the first three cleavage sites of its polyprotein, 3clpro is responsible for cleavage of the remaining eleven locations resulting in release of a total of 16 non-structural proteins (nsp) in both sars-and mers-covs. the homodimeric form of 3clpro is active in the presence of substrates. the crystal structure of 3clpro showed that each monomer is composed of three structural domains: domains i and ii form a chymotrypsinlike architecture with catalytic cysteine and are connected to a third c-terminal domain via a long loop (neddle, lountos, & waugh, 2015) . in the proteolytic site, all 3clpros prefer glutamine at p1 position and leucine, basic residues, small hydrophobic residues at p2, p3 and p4 positions, respectively (chuck, chow, wan, & wong, 2011) . at p1′ and p2′ positions, small residues are required. since the autocleavage process is essential for viral propagation, 3clpro is a good drug target for anti-coronaviral infection. in this study, we used a proteolytic method to probe mers-cov 3clpro inhibitory compounds with a synthetic peptide labelled with the edans-dabcyl fret (fluorescence resonance energy transfer) pair (liu et al., 2005) . since emission wavelengths of edans are widely overlapped with absorbance wavelengths of dabcyl, the energy emitted from edans will be quenched by dabcyl in a close proximity (10-100 å). therefore, an increment of fluorescence can be a sign to judge whether a substrate is cleaved or not in this design. hence from the fluorescence intensity change, the proteolytic activity of protease could be detected. with a synthetic peptide with the fret pair, a flavonoid library was screened to search mers-cov 3clpro inhibitory compounds. recent studies showed that some flavonoids have antiviral activity in some viruses (frabasile et al., 2017; jucá et al.,2018; kiat et al., 2006; yang, lin, zhou, liu, & zhu, 2017; zakaryan, arabyan, oo, & zandi, 2017) . therefore, we assayed flavonoids and tried to induce their structural property crucial to bind with mers-cov 3clpro. the coding sequence of mers-cov nsp5, a 3c-like protease (ncbi ref. seq. nc_019843.3) was synthesized chemically by bioneer and cloned into a bacteriophage t7-based expression vector. the plasmid dna was transformed into e. coli bl21 (de3) for protein expression. e. coli bl21 (de3) cells were grown on luria-bertani (lb) agar plates containing 150 μg/ml ampicillin. several colonies were picked and grown in capped test-tubes with 10 ml lb broth containing 150 μg/ml ampicillin. a cell stock composed of 0.85 ml culture and 0.15 ml glycerol was prepared and frozen at 193 k for use in a large culture. the frozen cell stock was grown in 5 ml lb medium and diluted into 2,000 ml fresh lb medium. the culture was incubated at 310 k with shaking until an od 600 of 0.6-0.8 was reached. at this point, expression of mers-cov 3clpro was induced using isopropyl-β-d-1-thiogalactopyranoside (iptg) at a final concentration of 1 mm. the culture was further grown at 310 k for 3 hr in a shaking incubator. cells were harvested by centrifugation at 7,650 g (6,500 rev min −1 ) for 10 min in a high-speed refrigerated centrifuge at 277 k. the cultured cell paste was resuspended in 25 ml of a buffer consisting of 50 mm tris-hcl ph 8.0, 100 mm nacl, 10 mm imidazole, 1 mm phenylmethylsulfonyl fluoride (pmsf) and 10 μg/ml dnase i. the cell suspension was disrupted using an ultrasonic cell disruptor (digital sonifier 450; branson). cell debris was pelleted by centrifugation at 24,900 g (15,000 rev min −1 ) for 30 min in a highspeed refrigerated ultra-centrifuge at 277 k. the protein was purified by affinity chromatography using a 5 ml hi-trap q column (ge healthcare) followed by a 5 ml hi-trap blue column (ge healthcare). the custom-synthesized fluorogenic substrate, dabcyl-ktsavlqsgfrkme-edans (anygen), was used as a substrate for the proteolytic assay using mers-cov 3clpro (kuo, chi, hsu, & liang, 2004) . this substrate contains the nsp4/nsp5 cleavage sequence, gvlq↓sg (wua et al., 2015) , and works as a generic peptide substrate for many coronavirus including mers-cov 3clpro. the peptide was dissolved in distilled water and incubated with each protease. a spectramax i3x multi-mode microplate reader (molecular devices) was used to measure spectral-based fluorescence. the proteolytic activity was determined at 310 k by following the increase in fluorescence (λ excitation = 340 nm, λ emission = 490 nm, bandwidths = 9, 15 nm, respectively) of edans upon peptide hydrolysis as a function of time. assays were conducted in black, 96-well plates (nunc) in 350 μl assay buffers containing protease and substrate as follows: for the mers-cov 3clpro assay, 1.84 μl of 0.19 mm protease containing 20 mm tris ph 8.0 was incubated with 8.75 μl of 0.1 mm substrate at 310 k for 2 hr before measuring relative fluorescence unit (rfu). before the assay, the emission spectra of 40 flavonoids were surveyed after illuminating at 340 nm to avoid the overlapping with the emission spectrum of edans. every compound was suitable to be tested. the final concentration of the protease, peptide and chemical used at the assay was 1, 2.5 and 20 μm each. at first, mers-cov 3clpro and chemical were mixed and preincubated at room temperature for 1 hr. the reaction was initiated by the addition of the substrate, and each well was incubated at 310 k for 2 hr. after 2 hr, we measured the fluorescence of the mixture on the black 96-well plate using the end-point mode of spectramax i3x where the excitation wavelength was fixed to 340 nm and the emission wavelength was set to 490 nm using 9, 15 nm bandwidth, respectively. all reactions were carried out in triplicate. among the first forty flavonoids (table s1 ), four of them were picked up to further assay at a concentration range of 2 μm-320 μm. ic50 value which is the value causing 50% inhibition of catalytic activity of mers-cov 3clpro was calculated by non-linear regression analysis using graphpad prism 7.03 (graphpad software). the proteolytic assay using mers-cov 3clpro in the presence of triton x-100 has been performed to differentiate artificial inhibitory activity of chemicals through non-specific binding with proteases by forming aggregate or complexation. the concentration used in this study was 0.01%. to confirm the feasibility of the assay method independently, the fluorescence spectra from tryptophans of mers-cov 3clpro with candidate inhibitors were investigated (lin, lan, guan, sheng, & zhang, 2009 ). the fluorescence measurements were recorded with a spectramax i3x multi-mode microplate reader (molecular devices) at excitation and emission wavelengths of 295 nm and 300-500 nm, respectively. the optimal excitation and emission wavelengths were determined by softmax pro. five tryptophans of mers-cov 3clpro showed a strong fluorescence emission with a peak at 340 nm at the excitation wavelength of 295 nm. in contrast, the flavonoids were almost non-fluorescent under the same experiment condition. each 40 μm chemical was incubated with 1 μm mers-cov 3clpro for 1 hr, and the fluorescence intensity of mers-cov 3clpro was measured. all the docking and scoring calculations were performed using the schrödinger suite of software (maestro, version 11.5.011). the compounds were extracted from the pubchem database in sdf format and were combined in one file. the file was then imported into maestro and prepared for docking using ligprep. the atomic co-ordinates of the crystal structure of mers-cov 3clpro (5wkj) were retrieved from the protein data bank and prepared by removing all solvent and adding hydrogens and minimal minimization in the presence of bound ligand using protein preparation wizard. ionizer was used to generate ionized state of all compounds at target ph 7.0 ± 2.0. this prepared low-energy conformers of the ligand were taken as the input for docking analysis. grids for molecular docking were built using receptor grid generation. compounds were docked using ligand docking mode with postdocking minimization including 5 poses per ligand. the docked poses were then refined using an xp (extra precision) option with the threshold value for rejecting minimized pose of 0.5 kcal/mol. the energies were calculated using the opls3 force field. the induced-fit docking protocol (sherman, day, jacobson, friesner, & farid, 2006) was run from the graphical user interface accessible within maestro 11.5.011. receptor sampling and refinement were performed on residues within 5.0 å of each ligand for each of the 20 ligand-protein complexes. with prime (jacobson et al., 2004) , a side-chain sampling and prediction module, the side-chains, as well as the backbone of the target protein, were energy minimized. a total of 20 induced-fit receptor conformations were generated for each of the eight test ligands. re-docking the test ligands into their respective 20 structures within 30.0 kcal/mol of their lowest energy structure. finally, the ligand poses were scored using a combination of prime and glidescore scoring functions . the amount of cell harvested for purification of mers-cov 3clpro was 3.01 g per 2,000 ml of e. coli culture. the protein was purified by ion chromatography using a 5 ml hi-trap q column (ge healthcare). the column was equilibrated with a buffer consisting of 20 mm bis-tris ph 7.0, and the pooled fractions were loaded. the column was eluted using a linear nacl gradient to 1.0 m nacl, and the protein was eluted at 0.16 m nacl. the pooled fractions were loaded on a 5 ml hi-trap blue column (ge healthcare) equilibrated with a buffer consisting of 10 mm sodium phosphate ph 7.0. the target protein was detected in unbound fractions. sds-page showed one band around 33(33,737.77da) kda, corresponding to the molecular weight of mers-cov 3clpro. the protein was concentrated to 31.14 mg/ml for protease assays in a buffer consisting of 10 mm sodium phosphate ph 7.0. the purified mers-cov 3clpro was different from the previous method (kumar et al., 2016) where the native form was obtained after removing of a his 6 -tag wih factor-xa. in our experiment, the enzyme activity was 10-fold decreased when the his 6 -tag protein was used (data not shown). that is due to the location of the his 6 -tag connected to the n-terminus of mers-cov 3clpro. the published crystal structure showed that the active site pocket might be easily hindered by the flexible n-terminal his 6 -tag. a flavonoid library consisting of ten different scaffolds was also built (figure 1 ). it contains three isoflavones, one isoflavane, six flavones, nine flavonols, four flavanols, five flavanones, one flavanonol, one prenylflavonoid, eight chalcones and two unclassified flavonoids (table s1 ). we applied the library to assay mers-cov 3clpro. since flavonoids are known to aggregate through a complexation and thus non-specifically inhibit various proteases, the assay in the presence of triton x-100 was performed. before assay, we tested the influence of triton x-100 on the catalytic activity of mers-cov 3clpro. as shown in the figure s1 , only a slight increment of the catalytic activity was observed even up to 0.1% triton x-100. therefore, we performed the experiment at the concentration of 0.01% triton x-100 where no significant interference was detected. using forty flavonoids, an inhibitory effect of each compound at 20 μm was tested. among them, herbacetin (3,4′,5,7,8-pentahydroxyflavone), isobavachalcone (2′,4,4′-trihydroxy-3′-(3-methyl-2-butenyl)chalcone), quercetin 3-β-d-glucoside (3,3′,4′,5,7-pentahydroxyflavone 3-β-d-glucoside) and helichrysetin (4,2′,4′-trihydroxy-6′methoxychalcone) were found to have prominent inhibitory activity (figure 2 ). the four compounds showed the severely reduced fluorescent intensity and thus represented their mers-cov 3clpro inhibitory activity. the experimental data were plotted as log inhibitor concentration versus per cent fluorescence inhibition (figure 2) . ic50 values obtained from the dose-dependent inhibitory curves of herbacetin, isobavachalcone, quercetin 3-β-d-glucoside and helichrysetin are 40.59, 35.85, 37.03 and 67.04 μm, respectively. in order to confirm the inhibitory activity of the flavonoids independently, a general tryptophan-based assay method was employed. tryptophan was well-known to emit its own fluorescence. therefore, if tryptophan is positioned adequately in proteins, the change in fluorescence intensity can reflect the binding state of chemicals and be used to judge interaction between proteins and chemicals. mers-cov 3clpro contains five tryptophan residues and thus displays a high fluorescence peak at 340 nm at the tryptophan excitation wavelength of 295 nm. we monitored the change in the fluorescence intensities of mers-cov 3clpro depending on the presence or absence of four chemicals. since each compound in the flavonoid library was almost non-fluorescent under the experiment condition, a change in fluorescence intensity reflects interactions between mers-cov 3clpro and chemicals. only the four inhibitory compounds obviously reduced the fluorescence intensity of mers-cov 3clpro (figure 3) . the decreased emission intensity confirmed the complex formation between mers-cov 3clpro and inhibitory compounds. in order to deduce the binding modes of the inhibitory flavonoids, an in-depth theoretical investigation through an induced-fit docking study was carried out. the interactions between mers-cov 3clpro and the inhibitory flavonoids were analysed to predict their binding affinities. top ranked structures (according to the glide scores) from the induced-fit docking results for herbacetin (−10.246), isobavachalcone (−9.364), quercetin 3-β-d-glucoside (−9.751) and helichrysetin (−9.953) were selected and hypothesized to be biological complexes. in order to compare binding affinities to their closest homologues ( figure s2 figure s3 . it is very obvious that the s1 site and hydrophobic s2 site of mers-cov 3clpro play a key role in predicted complexes. flavonoids are natural compounds with multiple pharmacological characteristics such as antioxidant, anti-inflammatory, analgesic, anti-carcinogenic, antibacterial infection, antifungal and antiviral properties (frabasile et al., 2017) . naringenin has therapeutic effects on various neurological, cardiovascular, gastrointestinal, rheumatological, metabolic and malignant disorders (rani et al., 2016) . it also represents antiviral function (zakaryan et al., 2017) . fisetin is a commercially available nutraceutical with anti-inflammatory, antioxidant, anti-tumorigenic, anti-invasive, anti-angiogenic, anti-diabetic, neuroprotective and cardioprotective effects (pal, pearlman, & afaq, 2016) . interestingly, fisetin has an anti-noroviral activity by inducing cytokines (seo & choi, 2017) . although some of flavonoids show an antiviral effect, a molecular mechanism of their antiviral activity was rarely known. in this study, we assayed the inhibitory activity of various flavonoids against mers-cov 3clpro. for the trial, a flavonoid library composed of nine different scaffolds plus one undefined group was constructed. they are classified based on a c6-c3-c6 skeleton and differ in the overall hydroxylation patterns and in the saturation of the heteroatomic ring c together with the position of the attached aromatic ring b (at the positions c-2 or c-3 of ring c) (jucá et al., 2018) . the flavonoid library was tested, and thus, a systematic analysis was possible. among the ten groups, isoflavones, isoflavane, flavanols and flavanones did not show any inhibitory activity over mers-cov 3clpro. the other groups contains some flavonoids displaying moderate inhibitory activity. however, four flavonoids, herbacetin, isobavachalcone, quercetin 3-β-d-glucoside and helichrysetin exhibited prominent inhibitory activity. the immediate inference of the primary scaffold required for binding with mers-cov 3clpro was as follows: first, the orientation of the aromatic ring b at the position c-2 of ring c is essential as shown in isoflavones and isoflavane. second, the saturated heteroatomic ring c is not preferred as shown in flavanols and flavanones. third, chalcone and flavonol scaffolds show a promising binding property. the more detailed structural comparison also provided valuable structural information required for the binding affinity of each flavonoid. helichrysetin is a chalcone derivative (van puyvelde et al., 1989) . therefore, we compared its inhibitory activity with a chalcone, cardamonin (2′,4′-dihydroxy-6′-methoxychalcone) which is the structurally identical homologue except one hydroxyl group at the 4-position of the benzyl moiety of chalcone. the inhibitory activity of cardamonin at the concentration of 40 μm was lower than that of helichrysetin ( figure 4 ). it implies that the 4-hydroxyl group of helichrysetin is functionally important to bind with mers-cov 3clpro. the structural comparison of cardamonin with isobavachalcone also indicated the modification effect of acetophenone ring of chalcone: the hydrophobic modification at the 3′-position of the acetophenone ring moiety of isobavachalcone improves its binding affinity to mers-cov 3clpro. intriguingly, the docking study shows that the 4-hydroxyl group of helichrysetin forms a hydrogen bond with the hydroxyl group of tyr54 of mers-cov 3clpro. since tyr54 is located deep inside of the hydrophobic s2 site, helichrysetin is inserted into deeper than cardamonin ( figure s3a ). as a result, helichrysetin seems to have a better affinity and thus represents a better inhibitory activity. in the flavonoid library, there are quite similar homologues of herbacetin, isobavachalcone and quercetin 3-β-d-glucoside. they are kaempferol (3,4′,5,7-tetrahydroxyflavone), 2,2′,4′-trihydroxychalcone and quercitrin (3,3′,4′,5,7-pentahydroxyflavone-3-l-rhamnoside), respectively ( figure s2 ). their mers-cov 3clpro inhibitory activity is lower than their corresponding compounds at 40 μm. herbacetin is a kaempferol derivative where one more hydroxide is attached at 8-position of kaempferol. the docking study indicates kaempferol derivatives occupy the s1 and s2 sites of mers-cov 3clpro ( figure s3b ). the hydroxyl group at 7-position looks important to bind at the s1 binding site. a f i g u r e 4 comparison of inhibitory activity between homologue flavonoids. the two homologue flavonoids are compared side by side. each of two bars represents the effect of two homologue inhibitory compounds at 40 μm against mers-cov 3clpro compared to the control. each bar is expressed as the mean ± standard error of the mean (n = 3). rfu = relative fluorescence units bit better inhibitory activity of herbacetin indicates the hydroxide at 8-position is favourable for its binding affinity to mers-cov 3clpro. in the predicted complex, the hydroxyl group at 8-position of herbacetin induces a hydrogen bond with his41 at the s1 site. the improved activity of isobavachalcone compared with 2,2′,4′-trihydroxychalcone again points out the importance of its hydrophobic substituent. coincided with the experimental result, the prenyl moiety of isobavachalcone makes hydrophobic interactions with met25 and leu49 at the hydrophobic s2 site ( figure s3c) . quercetin 3-β-d-glucoside is a homologue of quercitrin where rhamnoside is substituted for glucoside. the better inhibitory activity of quercetin 3-β-d-glucoside means that hydroxymethyl is preferred to hydroxide in this position of the glucoside to interact with mers-cov 3clpro. the docking study represents that the hydroxymethyl group of the glucoside moiety makes a hydrogen bond with glu169 and thus contributes its tighter binding to the s1 site than the rhamnoside moiety of quercitrin ( figure s3d ). helichrysetin and isobavachalcone inhibiting the activity of mers-cov 3clpro are chalcone derivatives. chalcone has immunomodulation, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, anticancer and anti-diabetic activities (yadav, prasad, sung, & aggarwal, 2011) . recently, the non-competitive inhibition of cardamonin against the dengue virus protease has been reported (kiat et al., 2006) . as discussed above, cardamonin is a strong homologue of helichrysetin. the analysis of the crystal structures of three viral proteases, mers-cov 3clpro, dengue virus ns2b/ns3 protease and norovirus 3clpro were performed, and their active sites were compared ( figure s4 ) (erbel et al., 2006; nakamura et al., 2005) . despite their sequential divergence, their overall architecture resembles each other. furthermore, the spatial positions of their catalytic residues were also highly conserved. the observation implies that chalcone and flavonol can be used as templates to develop a potential antiviral agent by targeting these viral proteases. in this study, we showed that the antiviral effects of some flavonoids may be directly from their inhibition of main viral proteases and thus nullify a process of virus peptides. therefore, one of antiviral mechanisms of flavonoids may be originated from their direct binding capability to viral proteases. consequently, flavonoid derivatives can be used as a template to design not only for broad-spectrum but also for virus-specific antiviral agents. a further study is going on to develop better inhibitory lead compounds derived from this study. we built a flavonoid library to systematically search mers-cov 3clpro inhibitory compounds with a fret method. we found four flavonoids effectively reducing the proteolytic activity of mers-cov 3clpro. the binding of the flavonoids was independently proven by a tryptophanbased fluorescence method. the assay in the presence of triton x-100 also eliminated the chance of the false-positive result from the aggregation of flavonoids. the analysis of the four compounds with their homologs using an induced-fit docking study provided an insight of flavonoid scaffolds required to bind with mers-cov 3clpro. the prominent activity of helichrysetin and isobavachalcone indicates that the flexibility of the chalcone scaffold is good to bind with mers-cov 3clpro. in contrast, the comparable activity of flavones with a rigid γ-pyrone ring indicates that their spatial rearrangement together with various functional groups may be an alternative strategy to interact with mers-cov 3clpro. therefore, this study suggests that an antiviral effect of some flavonoids is directly from their structural characteristics binding to viral proteases. profiling of substrate specificities of 3c-like proteases from group 1, 2a, 2b, and 3 coronaviruses sars and mers: recent insights into emerging coronaviruses structural basis for the activation of flaviviral ns3 proteases from dengue and west nile virus coronaviruses: an overview of their replication and pathogenesis the citrus flavanone naringenin impairs dengue virus replication in human cells extra precision glide: docking and scoring incorporating a model of hydrophobic enclosure for protein-ligand complexes a hierarchical approach to allatom protein loop prediction flavonoids: biological activities and therapeutic potential inhibitory activity of cyclohexenyl chalcone derivatives and flavonoids of fingerroot, boesenbergia rotunda (l.), towards dengue-2 virus ns3 protease identification, synthesis and evaluation of sars-cov and mers-cov 3c-like protease inhibitors characterization of sars main protease and inhibitor assay using a fluorogenic substrate spectroscopic investigation of interaction between mangiferin and bovine serum albumin screening of drugs by fret analysis identifies inhibitors of sars-cov 3cl protease a human coronavirus responsible for the common cold massively kills dendritic cells but not monocytes a norovirus protease structure provides insights into active and substrate binding site integrity structures of the middle east respiratory syndrome coronavirus 3c-like protease reveal insights into substrate specificity fisetin and its role in chronic diseases pharmacological properties and therapeutic potential of naringenin: a citrus flavonoid of pharmaceutical promise inhibitory mechanism of five natural flavonoids against murine norovirus novel procedure for modeling ligand/receptor induced fit effects isolation of flavonoids and a chalcone from helichrysum odoratissimum and synthesis of helichrysetin prediction and biochemical analysis of putative cleavage sites of the 3c-like protease of middle east respiratory syndrome coronavirus the role of chalcones in suppression of nf-κb-mediated inflammation and cancer activity of compounds from taxillus sutchuenensis as inhibitors of hcv ns3 serine protease flavonoids: promising natural compounds against viral infections the authors declare no conflict of interest. the data that support the findings of this study are available from the corresponding author upon reasonable request. https://orcid.org/0000-0002-2205-1453mi-sun kim https://orcid.org/0000-0002-4092-4203 key: cord-277541-ieex2xwx authors: sun, jian; wang, hexiang; ng, tzi bun title: trypsin isoinhibitors with antiproliferative activity toward leukemia cells from phaseolus vulgaris cv “white cloud bean” date: 2010-06-14 journal: j biomed biotechnol doi: 10.1155/2010/219793 sha: doc_id: 277541 cord_uid: ieex2xwx a purification protocol that comprised ion exchange chromatography on deae-cellulose, affinity chromatography on affi-gel blue gel, ion exchange chromatography on sp-sepharose, and gel filtration by fplc on superdex 75 was complied to isolate two trypsin inhibitors from phaseolus vulgaris cv “white cloud bean”. both trypsin inhibitors exhibited a molecular mass of 16 kda and reduced the activity of trypsin with an ic(50) value of about 0.6 μm. dithiothreitol attenuated the trypsin inhibitory activity, signifying that an intact disulfide bond is indispensable to the activity. [methyl-(3)h] thymidine incorporation by leukemia l1210 cells was inhibited with an ic(50) value of 28.8 μm and 21.5 μm, respectively. they were lacking in activity toward lymphoma mbl2 cells and inhibitory effect on hiv-1 reverse transcriptase and fungal growth when tested up to 100 μm. protease inhibitors have been purified from an array of leguminous and nonleguminous species encompassing torresea cearensis [1] , erythrina caffra [2] , dolichos lablab [3] , crotalaria paulina [4] , medicago scutellata [5, 6] , canavalia gladiata [7] , pisum sativum [8] , dimorphandra mollis [9] , swartzia pickellii [10] , psophocarpus tetragonolobus [11] , delonix regina [12] , poecilanthe parviflora [13] , adenanthera pavonina [14] , cajanus cajan [15] , dolichos biflorus [16] , phaseolus acutifolius [17] , arachis hypogaea [18] , leucaena leucocephala [19] , bauhinia bauhinioides [20] , bauhinia variegata [21] , bauhinia ungulata [22] , vigna unguiculata [23] , lens culinaris [24] , glycine max [25] , peltophorum dubium [26] , pithecellobium dulce [27] , glycine soja [28] , and barley [29] . protease inhibitors impair the activity of insect midgut proteases and thus adversely affect protein digestion and health in insects. they represent one of the multitude of entomotoxic proteins [30, 31] . in addition to insecticidal activity [32] [33] [34] [35] , protease inhibitors demonstrate antiproliferative and antitumor activities [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] . the objective of the present study was to isolate and characterize proteins with protease inhibitory activity from white cloud beans. inhibitor. an aqueous extract of the beans (250 g) was produced by blending in distilled water (3 ml/g) followed by centrifugation (14000 g for 25 minutes at 4 • c). the resulting supernatant was applied to a 5 × 20 cm column of deae-cellulose (sigma) in 10 mm tris-hcl buffer (ph 7.4). after elution of unadsorbed proteins (fraction d1), the column was eluted successively with 0.2 m nacl and 1 m nacl in the tris-hcl buffer. fraction d2 eluted with 0.2 m nacl was dialyzed to remove nacl and then subjected to affinity chromatography on a 5 × 15 cm of affi-gel blue gel (bio-rad) in 10 mm tris hcl buffer (ph 7.4). the unadsorbed fraction (b1) was dialyzed against 10 mm nh 4 oac buffer (ph 5) and then applied to a 2.5 × 20 cm column of sp-sepharose (ge healthcare). after elution of unadsorbed proteins (fraction s1), the column was eluted with a 0-1 m nacl concentration gradient in the nh 4 oac buffer. the first and second adsorbed fractions (sp2 and sp3) were then further purified by gel filtration on a superdex 75 hr 10/30 column (ge healthcare) in 0.2 m nh 4 hco 3 buffer (ph 8.5) using an akta purifier (ge healthcare). the second absorbance peak represented purified trypsin inhibitor. terminal sequence analysis. the molecular mass of the isolated proteins was determined by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (sds-page) following the procedure of laemmli and favre [46] . gel filtration on an fplc-superdex 75 column, previously calibrated with molecular mass marker proteins (ge healthcare), was employed to determine the molecular mass of the protein. the n-terminal sequence of the protein was analyzed by using a hewlett-packard hp g1000a edman degradation unit and an hp 1000 hplc system [47] . activity. the test sample (20 μl) was added to 160 μl of a 1% casein solution in 0.1 m tris-hcl buffer (ph 7.4). trypsin (20 μl of a 0.5 mg/ml solution) was then added and the mixture was incubated at 37 • c for 15 minutes followed by addition of trichloroacetic acid (0.4 ml, 5%) that was added to bring the reaction to an end. after centrifugation the absorbance of the resulting supernatant, which indicates the amount of casein fragments produced by trypsin, was read at 280 nm. the % inhibition of trypsin activity is equal to the % decrease in absorbance of the supernatant [48] . activity. the isolated trypsin inhibitor (2.5 μm) was treated with dithiothreitol (dtt) at the final concentration 2.5, 10 and 40 mm for 5, 20, and 80 minutes at 37 • c. soybean trypsin inhibitor from sigma (2.5 μm) was similarly treated and used as a positive control. the reaction was terminated by adding iodoacetamide at twice the amount of thiol functions at each dtt concentration. residual trypsin inhibitor activity was measured at ph 7.4 as described above in assay for trypsin inhibitory activity. the highest iodoacetamide concentration used in the test was devoid of any effect on trypsin activity and the trypsin inhibitory activity of isolated trypsin inhibitor and soybean trypsin inhibitor [47] . the antiproliferative activity of the purified trypsin inhibitor was assayed as described below. the cell lines l1210 (human leukemia) and mbl2 (murine lymphoma) were obtained from american type culture collection. the cell line was maintained in dulbecco modified eagles' medium (dmem) supplemented with 10% fetal bovine serum (fbs), 100 mg/l streptomycin, and 100 iu/ml penicillin, at 37 • c in a humidified atmosphere of 5% co 2 . cells (1 × 10 4 ) in their exponential growth phase were seeded into each well of a 96-well culture plate (nunc, denmark) and incubated for 3 hours prior to addition of the trypsin inhibitor. incubation was performed for an additional 48 hours. radioactive precursor, 1 μci ([ 3 h-methyl]-thymidine, from ge healthcare), was then introduced to each well and the incubation continued for 6 hours. the cultures were then harvested using a cell harvester. the radioactivity incorporated was measured in a liquid scintillation counter [49] . the assay for hiv reverse transcriptase inhibitory activity was carried out in view of the report that trypsin inhibitors manifest this activity [50, 51] . it was conducted according to instructions supplied with the assay kit from boehringer mannheim (germany). the assay makes following use of the ability of reverse transcriptase to synthesize dna, commencing from the template/primer hybrid poly (a) oligo (dt) 15. the digoxigenin-and biotin-labeled nucleotides in an optimized ratio are incorporated into one of the same dna molecule, which is freshly synthesized by the reverse transcriptase (rt). the detection and quantification of synthesized dna as a parameter for rt activity are based on a sandwich elisa protocol. biotin-labeled dna binds to the surface of microtiter plate modules that have been precoated with strepatavidin. in the following step, an antibody to digoxigenin, conjugated to peroxidase, binds to the digoxigenin-labeled dna. in the last step, the peroxidase substrate is added. the peroxidase enzyme affects the cleavage of the substrate, yielding a colored reaction product. the absorbance of the sample at 405 nm which is directly correlated to the level of rt activity can be measured using a microtiter plate (elisa) reader. a fixed amount (4-6 ng) of recombinant hiv-1 reverse transcriptase was used. the inhibitory activity of the trypsin inhibitor was calculated as percent inhibition compared to a control without the trypsin inhibitor [49] . integrase. the plasmid that expressed his-tagged wild-type hiv-1 integrase, pt7-7-his (y | tx)-hiv-1-in, was a generous gift from professor s.a. chow (school of medicine, ucla). to express the enzyme, a 1-liter culture of e. coli bl21 (de3) cells containing the expressing plasmid was grown at 37 • c until it reached od600 0.7-0.8. cells were induced by addition of 0.8 mm iptg (isopropyl-βd-thiogalactopyranoside) and harvested, after 4 hours of incubation, by centrifugation at 6000 g for 10 minutes at 4 • c. cells were suspended at a concentration of 10 ml/g wet cell paste in 20 mm tris-hcl buffer (ph 8.0) containing 0.1 mm edta, 2 mm β-mercaptoethanol, 0.5 m nacl, and 5 mm imidazole. lysozyme was added to a concentration of 0.2 mg/ml. after incubation at 4 • c for 1 hour, the lysate was sonicated and centrifuged at 40 000 g at 4 • c for 20 minutes. the pellet was homogenized in 50 ml buffer a (20 mm tris-hcl, ph 8.0, 2 m nacl, 2 mm β-mercaptoethanol) which contained 5 mm imidazole. the suspension was rotated at 4 • c for 1 hour and cleared by centrifugation at 40 000 g at 4 • c for 20 minutes. the supernatant was applied to a 1 ml chelating sepharose (ge healthcare) column charged with 50 mm imidazole. the column was eluted with five column volumes of buffer a containing 5 mm imidazole, and the protein was eluted with three column volumes of buffer a containing 200 and 400 mm imidazole, respectively. protein containing fractions were pooled, and edta was added to a final concentration of 5 mm, followed by dialysis against buffer b (20 mm hepes, ph 7.5, 1 mm edta, 1 m nacl, 20% glycerol) containing 2 mm βmercaptoethanol and then against buffer b containing 1 mm 2.9. assay for antifungal activity. this assay was performed since some trypsin inhibitors demonstrate antifungal activity [8] . the assay for antifungal activity toward botrytis cinerea and fuserium oxysporum was executed in 100 mm × 15 mm petri plates containing 10 ml of potato dextrose agar. after the mycelial colony had grown to a sufficiently large size, sterile blank paper disks (0.625 cm in diameter) were laid at a distance of 0.5 cm away from the edge of the mycelial colony. an aliquot (15 μl) of the trypsin inhibitor was added to a disk. the plates were exposed at 23 • c for 72 hours until mycelial growth had enveloped the disks containing the control and had produced crescents of inhibition around disks containing samples with antifungal activity [49] . anion exchange chromatography of the bean extract on deae-cellulose resolved it into three fractions, an unadsorbed fraction d1 together with two adsorbed fractions d2 and d3. trypsin inhibitory activity was confined to fraction d2. after affinity chromatography of fraction d2 on affi-gel blue gel, the activity appeared in the unadsorbed fraction b1 (data not shown). ion exchange chromatography of fraction b1 on sp-sepharose resolved it into a small unadsorbed fraction sp1 and three large adsorbed fractions (sp2, sp3, and sp4) of about the same size ( figure 1 ). trypsin inhibitory activity was detected in fractions sp2 and sp3. final purification of sp2 on superdex 75 produced two fractions, sp2su1 and sp2su2 (figure 2(a) ). gel filtration of sp3 on superdex 75 yielded two fractions sp3su1 and sp3su2 (figure 2(b) ). fractions sp2su2 and sp3su2, both with a molecular mass of 16 kda as determined by gel filtration on superdex 75, were the only fractions with trypsin inhibitory activity. the remaining fractions sp2su1 and sp3su1 were inactive. the yields of the various chromatographic fractions are presented in table 1 . both sp2su2 and sp3su2 displayed a molecular mass of 16 kda in sds-page ( figure 3 ) and gel filtration ( figure 2 ). their n-terminal sequences are shown in table 2 . these two white cloud bean trypsin inhibitors inhibited trypsin with an ic 50 of about 0.6 μm (figure 4) . inhibitor. dtt treatment curtailed the trypsin inhibiting activity in a doseand time-dependent manner ( table 3 ). the two trypsin inhibitors did not inhibit hiv-1 reverse transcriptase when tested at various concentrations up to 100 μm (table 4) . they lacked antifungal activity when tested up to 24 μg/disk (100 μm, 15 μl) (data not shown). the ic 50 values of the inhibitory effects of the trypsin inhibitors on l1210 cells were, respectively, 21.5 μm and 28.8 μm (table 4 ). however, there was no activity toward mbl2 cells when tested up to 100 μm. they showed marked homology to partial sequences of other leguminous trypsin inhibitors. the present study disclosed the production of two trypsin inhibitors with closely related n-terminal sequences chromatographic behavior and bioactivities by the white cloud bean variety of phaseolus vulgaris. the trypsin inhibitors demonstrate the same molecular mass; both are adsorbed on deae-cellulose and unadsorbed on affi-gel blue gel results are presented as mean ± sd (n = 3). different alphabets (e.g., a, b, and c) indicate statistically significant difference (p < .05) when (i) data at same time point and different dtt concentrations or (ii) data at same dtt concentration but different time point were analyzed by analysis of variance followed by duncan's multiple range test. figure 4 : inhibitory effects by the two white cloud bean trypsin inhibitors on trypsin. ic 50 = circa 0.6 μm. ic 50 for soybean trypsin inhibitor = 1.5 μm. results are presented as mean ± sd (n = 3). results are presented as mean ± sd (n = 3). ic 50 = 0.25 μm. different letters (a, b, c, d) next to the data points indicate statistically significant difference (p < .05) when the data are analyzed by analysis of variance followed by duncan's multiple range test. but can be separated by ion exchange chromatography on sp-sepharose. they have approximately the same trypsin inhibitory potency, and neither of them inhibits hiv-1 reverse transcriptase inhibitory activity, hiv-1 integrase inhibitory activity, sars coronavirus proteinase inhibitory activity, or fungal growth. both inhibitors exhibit an antiproliferative activity toward l1210 cells albeit with a small difference in potency, while there is little activity toward mbl2 cells. the difference in yields of the two trypsin inhibitors from the white cloud beans is only slight. the two trypsin inhibitors exhibit n-terminal sequence homology with those of other leguminous trypsin inhibitors such as inhibitors mungbean (vigna mungo), cowpea (vigna unguiculata), and lima bean (phaseolus lunatus). whereas leguminous antifungal proteins [48, 49] , like nonleguminous antifungal proteins [53] , are unadsorbed on deae-cellulose and adsorbed on affi-gel blue gel, white cloud bean trypsin inhibitors are adsorbed on deae-cellulose and unadsorbed on affi-gel blue gel. thus the purification procedure adopted in the present investigation can be conveniently used to separate trypsin inhibitors from antifungal proteins. the antiproliferative activity of white cloud bean trypsin inhibitors is consistent with similar observations on field bean trypsin inhibitor [39, 40, 42, 43, 54] . it is noteworthy that white cloud bean trypsin inhibitors do not exert a similar action on lymphoma mbl2 cells. thus the action of white cloud bean trypsin inhibitors is tumour cellspecific. the ribosome inactivating protein trichosanthin exerts different antiproliferative potencies toward different tumor cells [55] . in contrast to broad bean trypsin inhibitor [48, 56] , those from white cloud bean do not inhibit hiv-1 reverse transcriptase. a variety of trypsin inhibitors exhibit antifungal activity [48, 56] . however, white cloud bean trypsin isoinhibitors lack such activity. this is reminiscent of the finding that lentil and vigna mungo inhibitors have little or no hiv-1 reverse transcriptase inhibitory and antifungal activities [57, 58] . in summary, the isolation of two trypsin inhibitors with very similar biochemical and biological characteristics from white cloud beans was achieved in the present investigation. the presence of multiple trypsin inhibitors has previously been reported in momordica cochinchinensis seeds [59] . white cloud bean trypsin inhibitors demonstrate antiproliferative activity against tumor cells but do no inhibit mycelial growth or hiv-1 reverse transcriptase. previously isolated p. vulgaris trypsin inhibitors have not been so tested [60] [61] [62] [63] [64] . they reportedly have a molecular mass of about 9 kda [63, 65] or 13 kda [61] , smaller than the value of 16 kda obtained for white cloud bean trypsin inhibitors purification and primary structure determination of a bowman-birk trypsin inhibitor from torresea cearensis seeds the spectroscopic analysis, inhibition and binding studies demonstrate the equivalence of erythrina caffra trypsin inhibitor and the recombinant substitution variant rec-sereti purification and characterization of a proteinase inhibitor from field bean, dolichos lablab perpureus l isolation and characterization of a new trypsin inhibitor from crotalaria paulina seeds a trypsin inhibitor from snail medic seeds active against pest proteases effects of the medicago scutellata trypsin inhibitor (msti) on cisplatininduced cytotoxicity in human breast and cervical cancer cells complete amino acid sequences of three proteinase inhibitors from white sword bean (canavalia gladiata) pa1b, an insecticidal protein extracted from pea seeds (pisum sativum): 1h-2-d nmr study and molecular modeling purification and characterization of a new trypsin inhibitor from dimorphandra mollis seeds characterization of a kunitz trypsin inhibitor with one disulfide bridge purified from swartzia pickellii structure of a kunitz-type chymotrypsin inhibitor from winged bean seeds at 2.95å resolution primary sequence determination of a kunitz inhibitor isolated from delonix regia seeds trypsin inhibitor from poecilanthe parviflora seeds: purification, characterization, and activity against pest proteases a kunitz-type inhibitor of coleopteran proteases, isolated from adenanthera pavonina l. seeds and its effect on callosobruchus maculatus characterization of a proteinase inhibitor from cajanus cajan (l.) formation of bowman-birk inhibitors during the germination of horsegram (dolichos biflorus) unusual structural characteristics and complete amino acid sequence of a protease inhibitor from phaseolus acutifolius seeds cdna clone of a putative peanut (arachis hypogaea l.) trypsin inhibitor has homology with peanut allergens ara h 3 and ara h 4 molecular mechanism of enzyme inhibition: prediction of the three-dimensional structure of the dimeric trypsin inhibitor from leucaena leucocephala by homology modelling characterization of a tissue kallikrein inhibitor isolated from bauhinia bauhinioides seeds: inhibition of the hydrolysis of kininogen related substrates the complete amino acid sequence of a trypsin inhibitor from bauhinia variegata var. candida seeds human plasma kallikrein and tissue kallikrein binding to a substrate based on the reactive site of a factor xa inhibitor isolated from bauhinia ungulata seeds crystallization and preliminary x-ray diffraction studies of a bowman-birk inhibitor from vigna unguiculata seeds complete amino acid sequence of the lentil trypsin-chymotrypsin inhibitor lci-1.7 and a discussion of atypical binding sites of bowman-birk inhibitors phage display selection can differentiate insecticidal activity of soybean cystatins a novel trypsin inhibitor from peltophorum dubium seeds, with lectin-like properties, triggers rat lymphoma cell apoptosis isolation and properties of a kunitz-type protein inhibitor obtained from pithecellobium dulce seeds purification and characterization of proteinase inhibitors from wild soja (glycine soja) seeds crystal and molecular structure of the serine proteinase inhibitor ci-2 from barley seeds molecular characterization of a new arcelin-5 gene cloning and functional expression of a mungbean defensin vrd1 in pichia pastoris protein proteinase inhibitor genes in combat against insects, pests, and pathogens: natural and engineered phytoprotection effect of dietary cowpea trypsin inhibitor (cpti) on the growth and development of the tomato moth lacanobia oleracea (lepidoptera: noctuidae) and on the success of the gregarious ectoparasitoid eulophus pennicornis (hymenoptera: eulophidae) putative protein digestion in a sapsucking homopteran plant pest nilaparvata lugens: delphacidae)-identification of trypsinlike and cathepsin b-like proteases identification of potent inhibitors of helicoverpa armigera gut proteinases from winged bean seeds effects of protease inhibitors on growth of hamster tumor cells in culture inhibition of n-nitrosomethylbenzylamine-induced esophageal neoplasms by the bowman-birk protease inhibitor effects of various preparations of dietary protease inhibitors on oral carcinogenesis in hamsters induced by dmba field bean protease inhibitor preparations, unlike methotrexate, can completely suppress yoshida sarcoma tumor in rats inhibition of benzopyreneinduced forestomach tumors by field bean protease inhibitor(s) protein proteinase inhibitors in legume seedsoverview erratum: the field bean protease inhibitor can effectively suppress 72-dimethylbenz[a]anthracene-induced skin tumorigenesis in mice the field bean protease inhibitor has the potential to suppress b16f10 melanoma cell lung metastasis in mice protease inhibitors and carcinoma of the esophagus a soybean kunitz trypsin inhibitor suppresses ovarian cancer cell invasion by blocking urokinase upregulation maturation of the head of bacteriophage t4. i. dna packaging events the papaya kunitz-type trypsin inhibitor is a highly stable β-sheet glycoprotein a bowman-birk-type trypsinchymotrypsin inhibitor from broad beans gymnin, a potent defensinlike antifungal peptide from the yunnan bean (gymnocladus chinensis baill) pleureryn, a novel protease from fresh fruiting bodies of the edible mushroom pleurotus eryngii isolation and characterization of velutin, a novel low-molecular-weight ribosome-inactivating protein from winter mushroom (flammulina velutipes) fruiting bodies concurrent purification of two defense proteins from french bean seeds: a defensin-like antifungal peptide and a hemagglutinin isolation of cucurmoschin, a novel antifungal peptide abundant in arginine, glutamate and glycine residues from black pumpkin seeds treatment with field bean protease inhibitor can effectively repress ethylnitrosourea (enu)-induced neoplasms of the nervous system in sprague-dawley rats ribosome inactivating proteins (rips) from momordica charantia for anti viral therapy a new peptidic protease inhibitor from vicia faba seeds exhibits antifungal, hiv-1 reverse transcriptase inhibiting and mitogenic activities isolation and characterization of a trypsin-chymotrypsin inhibitor from the seeds of green lentil (lens culinaris) trypsinchymotrypsin inhibitors from vigna mungo seeds multiple trypsin inhibitors from momordica cochinchinensis seeds, the chinese drug mubiezhi trypsin isoinhibitors from garden beans (phaseolus vulgaris) the isolation and characterization of a trypsin inhibitor from kintoki bean (phaseolus vulgaris) isolation and characterization of some proteinase inhibitors from phaseolus vulgaris var. nanus fogo na serra" inhibitor and interactive surface modeling for the enzyme-inhibitor complex complete sequence, subunit structure, and complexes with pancreatic α-amylase of an α-amylase inhibitor from phaseolus vulgaris white kidney beans purification and characterization of an extracellular prolyl endopeptidase from agaricus bisporus this work was financially supported by national grants of china (nyhyzx07-008 and 2007bad89b00). key: cord-292286-ygomb3oi authors: zakaryan, hovakim; arabyan, erik; oo, adrian; zandi, keivan title: flavonoids: promising natural compounds against viral infections date: 2017-05-25 journal: arch virol doi: 10.1007/s00705-017-3417-y sha: doc_id: 292286 cord_uid: ygomb3oi flavonoids are widely distributed as secondary metabolites produced by plants and play important roles in plant physiology, having a variety of potential biological benefits such as antioxidant, anti-inflammatory, anticancer, antibacterial, antifungal and antiviral activity. different flavonoids have been investigated for their potential antiviral activities and several of them exhibited significant antiviral properties in in vitro and even in vivo studies. this review summarizes the evidence for antiviral activity of different flavonoids, highlighting, where investigated, the cellular and molecular mechanisms of action on viruses. we also present future perspectives on therapeutic applications of flavonoids against viral infections. throughout human history, thousands of biologically active plants have been identified and used in medicine. virtually all cultures around the world continue to rely on medicinal plants for primary health care. according to the world health organization report, about 80% of the world's population depend on medicinal plants to satisfy their health requirements [30] . furthermore, there are currently hundreds of modern drugs based on active compounds isolated from plants. plants have the ability to produce a wide range of compounds including flavonoids, phytoalexins, lignans, and tannins, which are responsible for key functions in plant growth and development. flavonoids or polyphenolics comprise the largest group of secondary metabolites found in vegetables, fruits, seeds, nuts, spices, stems as well as in red wine and tea (table 1 ) [88] . these compounds are synthesized in response to various abiotic stress conditions such as ultraviolet radiation and play an important role as defense agents against plant pathogens and insects [9, 84] . the first evidence of a biological activity of flavonoids was reported by albert szent-gyorgyii in 1938, who showed that citrus peel flavonoids prevent capillary bleeding and fragility associated with scurvy [109] . since then, a broad spectrum of biological activities such as anti-inflammatory, antioxidant, antibacterial, antiviral, anticancer, and neuroprotective has been described for flavonoids [40, 53, 65, 95, 137] . research for antiviral agents isolated from plants started in 1950s, when the activity of 288 plants against influenza a virus was evaluated in embryonated eggs [14] . during the last 60 years, several plants and plant-derived compounds with antiviral properties were identified. in this article, we review the results of both in vitro and in vivo experiments demonstrating the antiviral activity of flavonoids, especially focusing on those classes of flavonoids that have been extensively investigated. there are now more than 6000 varieties of flavonoids that have been structurally identified [35] . all these compounds comprise a flavan nucleus and a fifteen-carbon skeleton consisting of two benzene rings (a-and b-rings, as shown in fig. 1 ) connected via a heterocyclic pyrene ring (c-ring, as shown in fig. 1 ). flavonoids are divided into several classes such as anthocyanidins, flavones, flavonols, flavanones, flavan, isoflavanoids, biflavanoids, etc (table 1 ) [24] . the various classes of flavonoids differ in the level of oxidation and pattern of substitution of the pyrene ring, whereas individual compounds within the classes differ in the pattern of substitution of benzene rings. while in flavonoids the b-ring links to the c-ring at the c2 position, the b-ring of isoflavonoids is substituted at position c3 (fig. 1 ). biflavonoids comprise of two identical or non-identical flavonoid units conjoined through an alkyl-or alkoxybased linker (fig. 1) . in plants, flavonoids generally occur as aglycones, glycosides and methylated derivatives. they are biosynthesized through the phenylpropanoid pathway, transforming phenylalanine into 4-coumaroyl-coa, which then enters the flavonoid biosynthesis pathway [32] . depending on the plant species, a group of enzymes, such as hydroxylases and reductases, modify the basic flavonoid skeleton, resulting in the different flavonoid classes. finally, transferases modify the flavonoid skeleton with sugar, methyl groups and acyl moieties. these modifications alter the solubility and reactivity of flavonoids [6] . a large body of evidence supports the role of light in the regulation of flavonoid biosynthesis [156] . flavones constitute a major class in the flavonoid family based on a 2-phenyl-1-benzopyran-4-one backbone. natural flavones include apigenin, baicalein, chrysin, luteolin, scutellarein, tangeritin, wogonin and 6-hydroxyflavone. the antiviral activity of flavones is known from the 1990s, when it was showed that the simultaneous application of apigenin with acyclovir resulted in an enhanced antiviral effect on herpes simplex virus types 1 and 2 (hsv-1 and hsv-2) in cell culture [92] . apigenin is most commonly isolated in abundance from the family asteraceae. the organic and aqueous extracts from asteraceae plants with apigenin as a major compound were found to be active against hsv-1, poliovirus type 2 and hepatitis c virus (hcv) [85, 127] . apigenin isolated from sweet basil (ocimum basilicum) showed a potent antiviral activity against adenoviruses (adv) and hepatitis b virus in vitro [17] . besides these dna viruses, apigenin was found to exert antiviral effect against african swine fever virus (asfv), by suppressing the viral protein synthesis and reducing the asfv yield by 3 log [46]. apigenin is also active against rna viruses. for picronaviruses, it has been shown that apigenin is able to inhibit viral protein synthesis through suppressing viral ires activity [82, 107] . furthermore, apigenin affects enterovirus-71 (ev71) translation by disrupting viral rna association with trans-acting factors regulating ev71 translation [153] . shibata et al. [115] showed that apigenin has antiviral effect on hcv through the reduction of mature microrna122, a liver-specific microrna which positively regulates hcv replication. among flavones, baicalein and luteolin have been also extensively investigated with respect to their antiviral activity. baicalein significantly reduced the levels of human cytomegalovirus (hcmv) early and late proteins, as well as viral dna synthesis, although it had no effect on viral polymerase activity [23, 31] . baicalein impaired avian influenza h5n1 virus replication in both human lung epithelial cells and monocyte-derived macrophages by interfering with neuraminidase activity [116] . other studies showed that oral administration of baicalein to balb/c mice infected with influenza h1n1 virus decreased the lung virus titer and increased the mean time to death [139] . similar effects were recorded on mice infected with sendai virus [28] . these inhibitory effects in vivo were mediated by serum baicalin, a metabolite of baicalein which has a glucose residue [26] . baicalin alone exerts its anti-influenza activity by modulating the function of ns1 protein, which down-regulates ifn induction [99] . further studies indicated that baicalin can directly induce ifn-c production in human cd4 ? t cells and cd8 ? t cells and act as a potent inducer of ifn-c during influenza virus infection [19] . recently, novel baicalein analogs with b-rings substituted with bromine atoms demonstrated extremely potent activity against influenza h1n1 tamiflu-resistant virus, indicating that baicalein and its analogs can be favorable alternatives in the management of tamiflu-resistant viruses [21] . in vitro replication of hiv-1 was suppressed by baicalin when infected cells were treated during the early stage of the virus replication cycle [66] . hiv-1 envelope protein was found to be the target site of baicalin's antiviral action via the interference of interactions between the virus structural protein and specific host immune cells [75] . baicalein and baicalin were also investigated against dengue virus (denv). they exerted a significant virucidal effect on extracellular viral particles and interfered with different steps of denv-2 replication [91, 148, 150] . in silico studies revealed that baicalein has strong binding affinity with denv ns3/ns2b protein (-7.5 kcal/mol), and baicalin may interact closely with the virus ns5 protein at a binding affinity of -8.6 kcal/mol [47] . for baicalin, computational studies also showed a high binding affinity (-9.8 kcal/mol) against chikungunya virus (chikv) nsp3 protein, suggesting that baicalin can potentially interfere with chikv infection [114] . it was found that luteolin has antiviral effect on hiv-1 reactivation by blocking both clade b-and c-tat-driven ltr transactivation [87] . luteolin also showed significant inhibition of epstein-barr virus (ebv) reactivation in cells [133] ; it suppressed the activities of the immediate-early genes zta and rta by deregulating transcription factor sp1 binding. xu et al. [142] tested 400 highly purified natural compounds for inhibition of ev71 and coxsackievirus a16 infections and found that luteolin exhibited the most potent inhibition through disruption of viral rna replication. besides these antiviral activities, luteolin or luteolin-rich fractions showed antiviral effects against severe acute respiratory syndrome coronavirus (sars-cov), rhesus rotavirus, chikv and japanese encephalitis virus (jev) [33, 67, 94, 146] . flavonols are characterized by a 3-hydroxy-2-phenylchromen-4-one backbone. among flavonols the antiviral effect of quercetin was the most extensively investigated. early in vivo studies showed that oral treatment with quercetin protected mice from lethal mengo virus [44, 125] . furthermore, an enhanced protection was observed when quercetin was administered in combination with murine type i interferon (ifn) [125] . quercetin also demonstrated a dose-dependent antiviral activity against poliovirus type 1, hsv-1, hsv-2, and respiratory syncytial virus (rsv) in cell cultures [60, 83] . epimedium koreanum nakai, which contains quercetin as the major active component, has been shown to induce secretion of type i ifn, reducing the replication of hsv, newcastle disease virus (ndv), vesicular stomatitis virus (vsv) in vitro, as well as influenza a subtypes (h1n1, h5n2, h7n3 and h9n2) in vivo [18] . hung et al. [51] have suggested possible mechanisms whereby quercetin may exert its anti-hsv activity. they revealed that quercetin inhibits the infection of hsv-1, hsv-2 and acyclovirresistant hsv-1 mainly by blocking viral binding and penetration to the host cell. they also reported that quercetin suppresses nf-jb activation, which is essential for hsv gene expression. recent investigations also pointed out the antiviral activity of quercetin against a wide spectrum of influenza virus strains. it interacts with influenza hemagglutinin protein, thereby inhibiting viralcell fusion [136] . in addition, in silico analysis revealed that quercetin may be a potential inhibitor of the neuraminidase of influenza a h1n1 and h7n9 viruses [79, 80] . molecular docking analysis also found that quercetin may interact with hcv ns3 helicase, ns5b polymerase and p7 proteins [34, 86] . these results correlate with experimental studies showing the anti-hcv activity of quercetin through inhibition of ns3 helicase and heat shock proteins [4, 81] . besides these viruses, the inhibitory activity of quercetin and its derivatives have been reported for other viruses, including advs, arthropod-borne mayaro virus, porcine reproductive and respiratory syndrome virus, canine distemper virus, jev, denv-2, porcine epidemic diarrhea virus, and equid herpesvirus 1 [11, 16, 27, 38, 41, 59, 118, 149] . quercetin also possesses anti-rhinoviral effects by inhibiting endocytosis, transcription of the viral genome and viral protein synthesis [37] . in mice infected with rhinovirus, quercetin treatment decreased viral replication and attenuated virusinduced airway cholinergic hyper-responsiveness [37] . kaempferol is another flavonol extracted from different medicinal herbs. kaempferol and its derivatives bearing acyl substituents have shown inhibitory activity against hcmv [89] . kaempferol derivatives isolated from ficus benjamina leaves were more effective against hsv-1 and hsv-2 than their aglycon form [145] . kaempferol derivatives with rhamnose residue turned out to be potent inhibitors of the 3a channel of coronavirus, which is involved in the mechanism of virus release [112] . one of the kaempferol derivative, kaempferol 3-o-a-lrhamnopyranoside, obtained from zanthoxylum piperitum was shown to significantly inhibit the replication of influenza a virus in vitro [45] . behbahani et al. found that kaempferol and kaempferol-7-o-glucoside have strong hiv-1 reverse transcriptase inhibitory activity [5] . these compounds exerted their effects, at a concentration of 100 lg/ml, on the early stage of hiv replication in target cells. recently, kaempferol-3,7-bisrhamnoside isolated from chinese medicinal taxillus sutchuenensis was shown to have potent in vitro activity on hcv ns3 protease function [144] . antiviral activity of kaempferol on the influenza viruses h1n1 and h9n2 were mentioned in a study conducted by a group of researchers in south korea. mechanistic and structural studies suggested that the compound acts on the virus neuraminidase protein and specific functional groups are responsible for kaempferol's efficacy [57] . a study comparing the antiviral activities of kaempferol and an isoflavone, daidzein, showed that kaempferol exerted more potent inhibitory activities on jev replication and protein expression, than daidzein. jev's frameshift site rna (fsrna) has been proposed as the target site for kaempferol's inhibitory activity against this flavivirus [152] . seo et al. conducted a study comparing the potency of different classes of flavonoids against two rna viruses, namely murine norovirus and feline calicivirus. their findings demonstrated that, among the flavonoids tested, kaempferol exhibited the most potent inhibitory activity against these two viruses [113] . there are number of other flavonols and derivatives acting as antivirals. for example, sulfated rutin, which is modified from glycoside rutin, demonstrated significant activity against different hiv-1 isolates [123] . this compound inhibited hiv-1 infection by blocking viral entry and virus-cell fusion, likely by interacting with hiv-1 envelope glycoproteins. rutin at 200 lm concentration was shown to inhibit ev71 infection by suppressing the activation of mek1-erk signal pathway, which is required for ev71 replication of [129] . rutin and fisetin also inhibited the replication of ev-a71 by affecting the enzymatic activity of the 3c protease [76] . fisetin treatment caused a dose-dependent decrease in the production of chikv nonstructural proteins and inhibition of viral infection [73] . moreover, zandi et al. showed that denv-2 rna copy number was significantly reduced following addition of fisetin to infected cells [149] . yu et al. found that myricetin may serve as chemical inhibitor of sarscoronavirus because it affects the atpase activity of the viral helicase [147] . flavans are characterized by a 2-phenyl-3,4-dihydro-2hchromene skeleton. these compounds include flavan-3-ols, flavan-4-ols and flavan-3,4-diols. among flavan-3-ols, the antiviral activity of catechin and its derivatives epicatechin, epicatechin gallate, epigallocatechin (egc), and epigallocatechin gallate (egcg), which are found in tea, has been largely investigated [122] . among different viruses studied as potential targets, influenza virus has received the most attention after an initial report by nakayama et al. showing that tea catechins, particularly egcg, are able to bind to the haemagglutinin of influenza virus, preventing its adsorption to madin-darby canine kidney cells [98] . furthermore, it has been suggested that egcg may be able to damage the physical properties of the viral envelope, resulting in the inhibition of hemifusion events between influenza virus and the cellular membrane [66] . recently, colpitts and schang reported that egcg competes with sialic acid for binding to influenza a virus, thereby blocking the primary low-affinity attachment to cells [22] . another tea catechin, egc, exerted the inhibitory effect on the acidification of endosomes and lysosomes, thereby reducing viral entry via clathrin-mediated endocytosis [52]. a structure-function relationship analysis of tea catechins revealed the important role of the 3-gallolyl group of the catechin skeleton for its antiviral activity [120] . the results also showed that modification of the 3-hydroxyl position significantly affected the antiviral activity. catechin derivatives containing carbon chains at 3-hydroxyl position demonstrated potent anti-influenza activity in vitro and in ovo [121] . several reports have demonstrated that tea catechins have an antiviral effect against hiv infection. among tea catechins, egcg is the most effective because it exerts its antiviral effect throughout several steps of the hiv-1 life cycle. it directly binds to cd4 molecules with consequent inhibition of gp120 binding, an envelope protein of hiv-1 [62, 134] . these studies identified trp69, arg59 and phe43 of cd4 as potential sites for interaction with the galloyl moiety of egcg. the same residues are involved in interaction with viral gp120 [135] . furthermore, early studies from nakane and ono showed that egcg and ecg were effective at inhibiting hiv-1 reverse transcriptase in vitro [96, 97] . tillekeratne et al. modified the molecular structure of egcg to determine the minimum structural characteristics necessary for hiv-1 reverse transcriptase inhibition [124] . in their study, the gallate ester moiety was found to be important for inhibition. besides these effects, egcg has the ability to reduce viral production in chronically infected monocytoid cells [143] . the inhibitory effect was increased by approximately 25%, when egcg was modified with lyposomes. tea catechins are also effective against herpesviruses. egcg has been shown to block ebv lytic cycle by inhibiting expression of viral genes including rta, zta and ea-d [13] . further studies indicated that one of the mechanisms by which egcg may inhibit ebv lytic cycle involves the suppression of mek/erk1/2 and pi3-k/akt signaling pathways, which are involved in the ebv lytic cycle cascade [78] . isaacs et al. found that egcg can inactivate hsv virions by binding to the envelope glycoproteins gb and gd, which are essential for hsv infectivity [54] . the egcg digallate dimers theasinensin a, p2, and theaflavin-3,3'-digallate inactivated hsv-1 and hsv-2 more effectively than did monomeric egcg [55]. these dimers are stable at vaginal ph, indicating their potential to be antiviral agents against hsv infections. the inhibitory effect of green tea extracts against hbv has been reported [140] . in hepg2.117 cells, egcg inhibited hbv replication through impairing hbv replicative intermediates of dna synthesis, thereby reducing the production of hbv covalently closed circular dna [48] . in contrast, huang et al. found that egcg decreased hbv entry into immortalized human primary hepatocytes by more than 80% but had no effect on hbv genome replication [50]. furthermore, egcg is able to enhance lysosomal acidification, which is an unfavorable condition for hbv replication [155] . besides these viruses, egcg has been found to exert antiviral activity against hcv by preventing the attachment of the virus to the cell surface and suppressing rna replication steps [8, 15] . a recent study also showed inhibitory activity of egcg against another flavivirus, zika virus (zikv): in this study, foci forming unit reduction assays were performed to evaluate the antiviral activity of egcg on zikv at different stages of virus replication. foci observed showed more than 90% inhibition when the cells were treated with egcg during virus entry [10] . similarly, egcg is able to block chikv attachment to target cells, but has no effect on other stages of infection [132] . naringenin, which belongs to the flavanones class, has been shown to reduce the replication of a neurovirulent strain of sindbis virus in vitro [102] . it also reduced sindbis virus-and semliki forest virus-induced cytopathic effect in virus yield experiments [105] . interestingly, naringin, the glycoside form of naringenin did not have anti-sindbis virus activity, indicating that the rutinose moiety of this flavanone blocks its antiviral effect. naringenin is also able to block the assembly of intracellular hcv particles and long-term treatment leads to 1.4 log reduction in hcv [39, 64] . the alphavirus chikv was effectively inhibited when infected vero cells were treated with naringenin at the post-entry stage. in the same study, hesperetin, another flavanone which is found richly in citrus fruits, was found to exert most potent anti-chikv effect during the virus intracellular replication, with an ic 50 of 8.5 lm [1] . molecular docking and molecular dynamics studies by oo et al. also revealed strong and stable interactions between hesperetin and chikv nonstructural protein 2 (nsp2) as well as non-structural protein 3 (nsp3), suggesting that these proteins may be the target of hesperetin's anti-chikv activity [101] . genistein is an isoflavonoid found in a number of plants including soybeans and fava beans. as a tyrosine kinase inhibitor, genistein reduced bovine herpesvirus type 1 and new world arenavirus pichinde replication, by preventing the phosphorylation of viral proteins [2, 126] . kinase inhibitor cocktails containing genistein displayed a broadspectrum antiviral activity against arenaviruses and filoviruses [68] . genistein was shown to inhibit hiv infection of resting cd4 t cells and macrophages through interference with hiv-mediated actin dynamics [42] . furthermore, it may act against hiv ion channel since it has the ability to block the viral vpu protein, which is believed to form a cation-permeable ion channel in infected cells [110] . genistein also exerted its antiviral effects on the replication of hsv-1, hsv-2, and avian leucosis virus subgroup j, by inhibiting virus transcription [3, 106] . the antiviral activity of other flavonoids is presented in table 2 . in spite of the wide range of biological health benefits which flavonoids possess, in addition to their high availability in humans' daily diets, there are challenges ahead for researchers before these natural compounds can be applied as therapeutic options in the clinical setting. bioavailability, defined by the us food and drug administration as ''the rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action'', has been the main stumbling block to further advances in the potential use of flavonoids in the medical community. intake of metabolic derivatives of flavonoids from various food sources leads to relatively large differences in the final amount being successfully absorbed and utilized by humans [71] . factors such as molecular sizes, glycosylation, esterification, lipophilicity, interactions with the enteric microorganisms, pka, and other metabolic conjugations along the alimentary tract, affect the absorption and bioavailability of flavonoids in humans [49, 56, 69, 90, 93, 111, 133] . hence, efforts in enhancing the bioavailability of flavonoids upon intake by humans are vitally necessary in order to develop these natural compounds into potential antiviral drugs. the following are a few examples of efforts being carried out to tackle this issue which can be used as platforms for further successes in the future. in the past, researchers have looked into alternative methods to improve the compounds' solubility or to switch the site of absorption in the gut, with the aim of enhancing their bioavailability. a structural modification to hesperetin-7-glucoside, which resulted in a change in site of absorption from the large to the small intestine, has successfully yielded a higher plasma level of hesperetin in healthy subjects [100] . wang et al. [130] formulated a way to increase the oral bioavailability of flavonols extracted from sea buckthorn, by forming a phospholipid complex via solvent evaporation method. relative to the parent compounds, oral bioavailability of the tested flavonols was 172% -242% higher when the phospholipid complex was administered into rats [130] . flavonoids loaded in engineered nanoparticles have also been tested for their bioavailability following oral consumption. improved stability of catechin and egcg in chitosan nanoparticles have been shown to result in a higher rate of intestinal absorption [29] . poly (d, l-lactide) (pla) nanoparticles and polymeric micelles contributed to a more sustainable release of quercetin, which has poor bioavailability and undergoes substantial first-pass metabolism, as well as of the poorly absorbed apigenin [70, 124, 151] . self-microemulsifying drug delivery system (smdds) is another technology which has been used to overcome the problem of low bioavailability of hydrophobic molecules. upon entering the lumen of the intestine, an oil-in-water microemulsion containing the drug will be formed. the microemulsion increases the intestinal absorption of the drug or compound by avoiding the dissolution process [60, 108] . puerarin, an isoflavone isolated from the root of pueraria lobata, exhibited 2.6-fold higher bioavailability when prepared using smdds [154] . however, it is worth noting that while the bioavailability of flavonoids can be increased via different methodologies, it is vital that their biological efficacies are not affected, but maintained or enhanced. for instance, phosphorylated icariin has been found to inhibit duck hepatitis virus a more effectively than the parent compound [138] . isorhamnetin is a methylated flavonol derived from the structure of quercetin. dayem et al. investigated the antiviral potency of isorhamnetin against influenza a h1n1 virus and discovered that the methyl group on the b ring enhances its antiviral activity compared with the other tested flavonoids [25] . the efficacy of isorhamnetin against influenza virus was also shown when in vivo and in ovo models were tested [25] . improvement in bioavailability will definitely enhance the efficacy of different biological effects of all classes of flavonoids. hence, in addition to discovering the hidden potentials of flavonoids, scientists should also aim to identify ways to increase the amount of flavonoids available for the health benefits of human beings. natural compounds have been the center of attention among researchers working in various fields, including those related with antiviral drug development, due to their high availability and low side effects. the phytochemicals flavonoids, which are abundantly found in our daily diets of fruits and vegetables, have been actively studied as potential therapeutic options against viruses of different taxa in the past decade. numerous positive findings have been reported on the in vitro efficacy of flavonoids, but less promising results have been obtained for most compounds in in vivo studies. multiple factors contributed to this scenario, and in vivo studies must be prioritized by researchers. it is well-known that flavonoids possess enormous potential to be included in the daily prescriptions by physicians treating illnesses ranging from infectious and oncogenic to inflammatory and chronic degenerative diseases. however, it is time for researchers worldwide to take the initiative in making these compounds a success not only in the in vitro stage of research, but also in animal models, as well as in subsequent clinical studies. biochemistry and mechanistic studies on the flavonoids' inhibitory activities can improve our understanding of how these natural compounds work and, on the other hand, identify the stumbling block that is hindering further improvements in flavonoids antiviral research. (7) inhibition of chikungunya virus replication by hesperetin and naringenin effect of genistein on replication of bovine herpesvirus type 1 antiherpes evaluation of soybean isoflavonoids suppression of hepatitis c virus by the flavonoid quercetin is mediated by inhibition of ns3 protease activity in vitro anti-hiv-1 activities of kaempferol and kaempferol-7-o-glucoside isolated from securigera securidaca glycosyltransferases: managers of small molecules structural basis of inhibitor specificity of the human protooncogene proviral insertion site in moloney murine leukemia virus (pim-1) kinase epigallocatechin-3-gallate is a new inhibitor of hepatitis c virus entry flavonoids and melanins: a common strategy across two kingdoms the green tea molecule egcg inhibits zika virus entry in vitro inhibition of canine distemper virus by flavonoids and phenolic acids: implications of structural differences for antiviral design effect of naringenin, hesperetin and their glycosides forms on the replication of the 17d strain of yellow fever virus inhibition of epstein-barr virus lytic cycle by (-)-epigallocatechin gallate the action of plant extracts on a bacteriophage of pseudomonas pyocyanea and on influenza a virus epigallocatechin-3-gallate inhibits the replication cycle of hepatitis c virus in vitro antiviral activities of caesalpinia pulcherrima and its related flavonoids antiviral activities of extracts and selected pure constituents of ocimum basilicum epimedium koreanum nakai displays broad spectrum of antiviral activity in vitro and in vivo by inducing cellular antiviral state role of baicalin in anti-influenza virus a as a potent inducer of ifngamma inhibitory effects of flavonoids on moloney murine leukemia virus reverse transcriptase activity synthesis and anti-influenza activities of novel baicalein analogs a small molecule inhibits virion attachment to heparan sulfate-or sialic acid-containing glycans eight flavonoids and their potential as inhibitors of human cytomegalovirus replication the chemistry and biological effects of flavonoids and phenolic acids antiviral effect of methylated flavonol isorhamnetin against influenza antiviral activity of baicalin against influenza a (h1n1/ h3n2) virus in cell culture and in mice and its inhibition of neuraminidase quercetin and quercetin 3-o-glycosides from bauhinia longifolia (bong.) steud. show anti-mayaro virus activity effects of baicalein on sendai virus in vivo are linked to serum baicalin and its inhibition of hemagglutinin-neuraminidase chitosan nanoparticles enhance the intestinal absorption of the green tea catechins (?)-catechin and (-)-epigallocatechin gallate the growing use of herbal medicines: issues relating to adverse reactions and challenges in monitoring safety human cytomegalovirus-inhibitory flavonoids: studies on antiviral activity and mechanism of action flavonoids: biosynthesis, biological functions, and biotechnological applications antiviral activity ofl uteolin against japanese encephalitis virus docking studies of pakistani hcv ns3 helicase: a possible antiviral drug target structure and function of enzymes involved in the biosynthesis of phenylpropanoids inhibition of infectivity of potato virus x by flavonoids quercetin inhibits rhinovirus replication in vitro and in vivo inhibition of hsp70 reduces porcine reproductive and respiratory syndrome virus replication in vitro naringenin inhibits the assembly and long-term production of infectious hepatitis c virus particles through a ppar-mediated mechanism polyphenols as mitochondria-targeted anticancer drugs in vitro assessment of the antiviral potential of trans-cinnamic acid, quercetin and morin against equid herpesvirus 1 genistein interferes with sdf-1-and hiv-mediated actin dynamics and inhibits hiv infection of resting cd4 t cells anti-hepatitis b virus activity of wogonin in vitro and in vivo effect of quercetin on the course of mengo virus infection in immunodeficient and normal mice. a histologic study antiviral effect of flavonol glycosides isolated from the leaf of zanthoxylum piperitum on influenza virus antiviral activity of flavonoids 2547 anti-h1n1 virus, cytotoxic and nrf2 activation activities of chemical constituents from scutellaria baicalensis antiviral activity of baicalein and quercetin against the japanese encephalitis virus development of self-microemulsifying drug delivery systems (smedds) for oral bioavailability enhancement of simvastatin in beagle dogs antiviral effect of flavonoids on human viruses epigallocatechin gallate, the main component of tea polyphenol, binds to cd4 and interferes with gp120 binding development of chemical inhibitors of the sars coronavirus: viral helicase as a potential target divergent antiviral effects of bioflavonoids on the hepatitis c virus life cycle fisetin: a dietary antioxidant for health promotion inhibition of influenza virus internalization by (-)-epigallocatechin-3-gallate an evaluation of the inhibitory effects against rotavirus infection of edible plant extracts inhibition of lassa virus and ebola virus infection in host cells treated with the kinase inhibitors genistein and tyrphostin chemistry and biological activities of flavonoids: an overview development of biodegradable nanoparticles for delivery of quercetin updated knowledge about polyphenols: functions, bioavailability, metabolism, and health antiviral activity of selected flavonoids against chikungunya virus -o-arylmethylgalangin as a novel scaffold for anti-hcv agents flavonoid baicalin inhibits hiv-1 infection at the level of viral entry fisetin and rutin as 3c protease inhibitors of enterovirus a71 structure-activity relationship of flavonoids as influenza virus neuraminidase inhibitors and their in vitro anti-viral activities epigallocatechin-3-gallate inhibition of epstein-barr virus spontaneous lytic infection involves erk1/2 and pi3-k/akt signaling in ebv-positive cells computational screen and experimental validation of anti-influenza effects of quercetin and chlorogenic acid from traditional chinese medicine molecular docking of potential inhibitors for influenza h7n9 quercetin: bioflavonoids as part of interferon-free hepatitis c therapy? apigenin inhibits enterovirus 71 replication through suppressing viral ires activity and modulating cellular jnk pathway antiherpetic activities of flavonoids against herpes simplex virus type 1 (hsv-1) and type 2 (hsv-2) in vitro phenolic acids act as signaling molecules in plant-microbe symbioses identification and evaluation of antihepatitis c virus phytochemicals from eclipta alba computational docking study of p7 ion channel from hcv genotype 3 and genotype 4 and its interaction with natural compounds a flavonoid, luteolin, cripples hiv-1 by abrogation of tat function the effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer evaluation of the antiviral activity of kaempferol and its glycosides against human cytomegalovirus metabolomics view on gut microbiome modulation by polyphenol-rich foods baicalin, a metabolite of baicalein with antiviral activity against dengue virus combined effects of flavonoids and acyclovir against herpesviruses in cell cultures absorption, excretion and metabolite profiling of methyl-, glucuronyl-, glucosyland sulpho-conjugates of quercetin in human plasma and urine after ingestion of onions anti-chikungunya activity ofl uteolin and apigenin rich fraction from cynodon dactylon neuroprotective effects of chrysin: from chemistry to medicine differential inhibition of hiv-reverse transcriptase and various dna and rna polymerases by somecatechin derivatives differential inhibitory effects of some catechin derivatives on the activities of human immunodeficiency virus reverse transcriptase and cellular deoxyribonucleic and ribonucleic acid polymerases inhibition of the infectivity of influenza virus by tea polyphenols antiviral activity of baicalin against influenza virus h1n1-pdm09 is due to modulation of ns1-mediated cellular innate immune responses bioavailability is improved by enzymatic modification of the citrus flavonoid hesperidin in humans: a randomized, double-blind, crossover trial silico study on anti-chikungunya virus activity of hesperetin anti-sindbis activity of flavanones hesperetin and naringenin anti-hiv-1 activity of flavonoid myricetin on hiv-1 infection in a dual-chamber in vitro model plant derived compounds having activity against p388 and l1210 leukemia cells inhibitors of alphavirus entry and replication identified with a stable chikungunya replicon cell line and virus-based assays genistein inhibits the replication of avian leucosis virus subgroup j in df-1 cells apigenin restricts fmdv infection and inhibits viral ires driven translational activity anti-inflammatory effect of quercetin-loaded microemulsion in the airways allergic inflammatory model in mice drugs of natural origin genistein as antiviral drug against hiv ion channel absorption and metabolism of polyphenols in the gut and impact on health kaempferol derivatives as antiviral drugs against the 3a channel protein of coronavirus comparison of the antiviral activity of flavonoids antiviral activity of flavonoids against murine norovirus and feline calicivirus computational approach towards exploring potential anti-chikungunya activity of selectedflavonoids the flavonoid apigenin inhibits hepatitis c virus replication by decreasing mature microrna122 levels differential antiviral and anti-inflammatory mechanisms of the flavonoids biochanin a and baicaleinin h5n1 influenza a virus-infected cells antiviral activity of chrysin derivatives against coxsackievirus b3 in vitro and in vivo quercetin 7-rhamnoside reduces porcine epidemic diarrhea virus replication via independent pathway of viral induced reactive oxygen species silymarin efficacy against influenza a virus replication antiviral effect of catechins in green tea on influenza virus biological evaluation of anti-influenza viral activity of semi-synthetic catechin derivatives tea catechins as a potential alternative anti-infectious agent in vitro anti-hiv and -hsv activity and safety of sodium rutin sulfate as a microbicide candidate simplified catechin-gallate inhibitors of hiv-1 reverse transcriptase synergistic action of quercetin and murine alpha/beta interferon in the treatment of mengo virus infection in mice genistein treatment of cells inhibits arenavirus infection in vitro antiviral activity of plant extracts from asteraceae medicinal plants multiple effects of silymarin on the hepatitis c virus lifecycle saururus chinensis (lour.) baill blocks enterovirus 71 infection by hijacking mek1-erk signaling pathway a phospholipid complex to improve the oral bioavailability of flavonoids antienterovirus 71 effects of chrysin and its phosphate ester the green tea catechin, epigallocatechin gallate inhibits chikungunya virus infection colonic metabolites of berry polyphenols: the missing link to biological activity? epigallocatechin gallate, the main polyphenol in green tea, binds to the t-cell receptor, cd4: potential for hiv-1 therapy kinetic and structural analysis of mutant cd4 receptors that are defective in hiv gp120binding quercetin as an antiviral agent inhibits influenza a virus (iav) entry. viruses biological activities of polyphenols from grapes determine the structure of phosphorylated modification of icariin and its antiviral activity against duck hepatitis virus a inhibitory effects of baicalein on the influenza virus in vivo is determined by baicalin in the serum green tea extract and its major component epigallocatechin gallate inhibits hepatitis b virus in vitro tangeretin from citrus reticulate inhibits respiratory syncytial virus replication and associated inflammation in vivo identification of luteolin as enterovirus 71 and coxsackievirus a16 inhibitors through reporter viruses and cell viability-based screening inhibitory effects of (-)-epigallocatechin gallate on the life cycle of human immunodeficiency virus type 1 (hiv-1) activity of compounds from taxillus sutchuenensis as inhibitors of hcv ns3 serine protease potent antiviral flavone glycosides from ficus benjamina leaves small molecules blocking the entry of severe acute respiratory syndrome coronavirus into host cells identification of myricetin and scutellarein as novel chemical inhibitors of the sars coronavirus helicase, nsp13 extract of scutellaria baicalensis inhibits dengue virus replication antiviral activity of four types of bioflavonoid against dengue virus type-2 novel antiviral activity of baicalein against dengue virus preparation and in vitro evaluation of apigenin-loaded polymeric micelles anti-japanese-encephalitis-viral effects of kaempferol and daidzin and their rna-binding characteristics apigenin inhibits enterovirus-71 infection by disrupting viral rna association with trans-acting factors characterization and evaluation of self-microemulsifying sustained-release pellet formulation of puerarin for oral delivery epigallocatechin-3-gallate opposes hbv-induced incomplete autophagy by enhancing lysosomal acidification, which is unfavorable for hbv replication light-controlled flavonoid biosynthesis in fruits acknowledgements the authors acknowledge all reviewers whose detailed comments improved the review and apologize to those authors whose contribution to flavonoids antiviral research may have been inadvertently missed. ethical standards this study is supported by the ra mes state committee of science, in the frames of the research projects 15rf-081 and 16yr-1f064. all authors declare that they have no conflict of interest. this article does not contain any studies with human participants or animals performed by any of the authors. key: cord-303468-95btvr1v authors: verran, joanna; jackson, sarah; scimone, antony; kelly, peter; redfern, james title: biofilm control strategies: engaging with the public date: 2020-07-30 journal: antibiotics (basel) doi: 10.3390/antibiotics9080465 sha: doc_id: 303468 cord_uid: 95btvr1v there are few peer-reviewed publications about public engagement with science that are written by microbiologists; those that exist tend to be a narrative of an event rather than a hypothesis-driven investigation. however, it is relatively easy for experienced scientists to use a scientific method in their approach to public engagement. this short communication describes three public engagement activities hosted by the authors, focused on biofilm control: hand hygiene, plaque control and an externally applied antimicrobial coating. in each case, audience engagement was assessed using quantitative and/or qualitative methods. a critical evaluation of the findings enabled the construction of a public engagement ‘tick list’ for future events that would enable a hypothesis-driven approach with more effective communication activities and more robust evaluation. it is increasingly being recognised by 'experts' that science literacy is of key importance for the public [1] . at a time where antimicrobial resistance (amr) continues to pose significant public health threats (or indeed, at a time of a global pandemic), an understanding of statistics, epidemiology and microbiology is even more desirable. as a subject, microbiology offers many topics with which we can engage non-experts, such as microbial diversity (including fungi, algae, protozoa and viruses as well as bacteria), beneficial microbes (for example, probiotics, fermented foods, the human microbiome), and messages that can influence behaviour in a positive manner (including vaccination, hand hygiene, antimicrobial stewardship) [2] [3] [4] . biofilms (an assemblage of microbial cells that are irreversibly associated with a surface-not removed by gentle rinsing-and enclosed in a matrix of primarily polysaccharide material [5] ) are of great importance to microbiologists, but also to many other professionals (such as engineers, biocide manufacturers, architects), and are found in a variety of environments (water distribution systems, industrial processing, hospitals). biofilm research is multi-disciplinary, extensive and significant, with many applications. there are several research centres which focus on biofilm, such as the us-based centre for biofilm engineering (http://www.biofilm.montana.edu/) and the uk-centred national biofilm innovation centre (https://www.biofilms.ac.uk/), and conferences about biofilm are regular and not uncommon. some individual researchers, research groups and research centres are keen to engage with external public audiences through outreach activities, although evidence of such activities (websites, articles, learning materials and other peer-reviewed outputs) is not easy to find. but why do we want the public to know about biofilms? and what does the 'public' need to know about biofilms? 'now wash your hands' was developed as part of a university faculty family fun day during national science and engineering week/healthcare science week in the uk. the aim was to raise awareness of effective handwashing, whilst also engaging the participants in a discussion about the skin microbiome/biofilm. this event guarantees an audience of predominantly families who are likely to have an existing interest in science. hand hygiene activities are well established as interactive learning activities with demonstrable public health impact (for example, as an intervention in reducing the spread of coronavirus [6] ). in this activity, demonstrators (academic staff and student volunteers) engaged audiences to demonstrate surface contamination and effective handwashing ( figure 1 ). thus, visitors at this activity (in a walkway area) had their hands 'contaminated' with a uv hand gel (www.hand-washing.com). this kit uses a fluorescent dye and ultraviolet light to illustrate the transmission of 'germs' from hands to other surfaces (and vice versa) and the importance of handwashing. in addition, the participants were invited to press their hands onto large agar plates for subsequent incubation to reveal the culturable microorganisms present on their skin. of course, they were unable to see the results of this work until after incubation, thus images of plates pre-inoculated with microorganisms present on hands and mobile phones [7] were available to view, and post-incubation images of their own plates were uploaded to flickr, a social media site that hosts images (http://tinyurl.com/howcleanareyourhands, figure 2 ). within a week from results going online, almost 100 downloads were recorded (the participants were provided with a card/web address), equivalent to the number of plates inoculated. from this, we deduced that visitors demonstrated interest and engagement with the activity. throughout the activity, conversations were ongoing. it was unfortunate that these interactions were not noted in some form: informal observations revealed points of interest from the participants such as their inability to clean hands effectively (especially the adults!) and amazement at the mobile phone contamination. the handprint technique has been used as an engagement tool for other events, such as an art installation called 'hands across the cultures' for registrants to a qualitative research conference and as part of the 'bioselfies' project (https://blogs.bl.uk/science/2020/02/introducing-bio-selfies-11-february-2020.html) initiated by the university of salford. flickr has been used for other events that require incubation of plates [8, 9] , and download numbers have on occasion exceeded the number of images posted, showing that the participants may have been sharing the findings with others. the fluorescent hand technique was used to illustrate person-to-person transmission by handshaking prior to a screening of the movie contagion (directed by soderbergh, 2011). one person 'contaminated' his/her hands, shook the hand of their neighbour, who shook her/his neighbour's hand and so on. thus, the passing-on of fluorescence was used to illustrate the transmission of infection through poor hand hygiene, reinforcing the message as to how the movie pandemic was initiated (hand contact). hand hygiene activities are common in microbiology engagement, the aim of the activity being primarily to inform, and hopefully to change, participants' behaviour so that effective handwashing hand hygiene activities are common in microbiology engagement, the aim of the activity being primarily to inform, and hopefully to change, participants' behaviour so that effective handwashing hand hygiene activities are common in microbiology engagement, the aim of the activity being primarily to inform, and hopefully to change, participants' behaviour so that effective handwashing techniques are employed. explanation regarding the presence or importance of the antibiotics 2020, 9, 465 4 of 12 skin microbiome/biofilm are likely rare (especially if the results are not available until a later date): the activity is inevitably more focused on the removal of temporary contaminants and on the importance of good handwashing. some discussion could take place regarding the hygiene-versus-cleanliness hypothesis [10, 11] . the flickr method used for posting images and monitoring downloads at least gives an indication of interest, but much more could be made of this activity. it would also be interesting to know if the 'good handwashing' messages are retained and employed in the future. however, longitudinal studies are rare in this type of public engagement, probably because of the significant advanced planning required in terms of gaining approval for personal data access (e.g., emails) and also because only short-term awareness raising tends to be the primary aim of the activity. the plaque biofilm is one of the best-known medical biofilms [12, 13] , and oral hygiene advertising frequently provides cartoons of plaque being removed to demonstrate the effectiveness of a paste, mouthwash or brush. it is known that good toothbrushing helps to remove plaque [14] and should be carried out regularly. different dentifrices claim varying activities, but virtually all formulations include fluoride (to 'strengthen the teeth') [15] , and many contain antimicrobial agents (to reduce the number of microorganisms, with claims around gum health) [16] . 'plaque attack!' was a laboratory-based activity designed for children and their parents, taking place during manchester science festival's family fun day at manchester metropolitan university. the aim of the event was to encourage good oral hygiene but also to captivate visitors with the components of the plaque biofilm as well as the laboratory and its equipment. being time-consuming and space-limited, the participants had to register for the event, were limited to 3 groups of 20 participants, be escorted to the laboratory, provided with appropriate clothing and instruction and supervised at all times. oral microbiology is a key research area in our laboratories, and the delivery team thought it would be valuable for visitors to encounter activity in a working (teaching) laboratory. the delivery team comprised phd students, technical staff and an academic. several activities were conducted as part of a 'round-robin' activity: sampling plaque (microscopy demonstration and take-home photo [zip mobile printer, polaroid]); disclosing plaque (using commercially available disclosing tablets), with photographs taken before and after cleaning teeth (in a wash area adjacent to the laboratory); looking at cultures of oral bacteria on agar plates; investigating biofilm structure/building a biofilm (using 'model magic' [crayola bedford uk], a white air-drying modelling clay) ( figure 3a ); and destroying a biofilm (using a water pistol to remove plaque (whose microorganisms were pre-constructed from fimo, a multi-coloured clay which can be hardened in the oven [www.staedtler. com]) hampered by plaque matrix (a translucent hair gel) [17] (figure 3b ). the participants were provided with a basic information sheet on plaque and oral hygiene, onto which they could attach their polaroid images. they were also given a bag containing complimentary toothbrush and toothpaste (courtesy of unilever [www.unilever.co.uk]). at the end of the activity, they were asked for free text feedback on what they thought of the event, and the information was coded into categories to allow for comparison [18, 19] (figure 4) . the participants were particularly engrossed in the microscopy demonstration, being able to see their own plaque at high magnification. they also clearly had fun 'destroying' the biofilm but were less interested in the more passive/less exciting activity (agar plates demonstration, building a biofilm). the free text provided by the participants (allowing more thorough insight compared to multiple-choice or leading questions such as 'give three things you have learned', or 'smiley face/sad face' evaluations [18, 20] ) gave valuable qualitative information that was used to inform subsequent activities. (a/top) participants at the 'plaque attack!' event were encouraged to create their own oral bacteria flora from modelling clay, which was assembled into the oral biofilm representation here shown. (b/bottom) participants were encouraged to 'destroy a biofilm' by removing bacteria (coloured plastic pieces) encased in biofilm extracellular matrix (hair gel) with a spray bottle filled with water. there was a total of 19 comments that were coded based on their focus-with each comment possibly being coded into more than one category. our research into titanium dioxide coatings included a range of laboratory-based studies that compared different titanium dioxide concentrations in paint formulations [21] . the work described . themes identified from 'plaque attack!' feedback. there was a total of 19 comments that were coded based on their focus-with each comment possibly being coded into more than one category. our research into titanium dioxide coatings included a range of laboratory-based studies that compared different titanium dioxide concentrations in paint formulations [21] . the work described in this paper was to see whether the effect of a photocatalyst in paint could be detected by the human eye. thus, as part of a phd project investigating the activity of photocatalytic surfaces, one of the external walls of the university was used to illustrate the effectiveness of titanium dioxide paints in terms of self-cleaning and reduction of the formation of biofilm on the wall material. photocatalytic material such as titanium dioxide can exhibit self-cleaning, anti-fouling and antimicrobial properties in the presence of light, which makes these materials excellent candidates for incorporation into urban buildings and infrastructure [22] [23] [24] . the self-cleaning properties stem from their superhydrophilic nature-as, for instance, that of a liquid (e.g., rain) rolling off the surface of a continuous body. this sheeting carries away dirt and debris, cleaning the surface in the process-as seen in the sydney opera house [25] . thus, biofilm formation on the surface is delayed or prevented. in our study, the wall, comprising concrete panels (smaller panels 190 cm × 76 cm, larger panels 406 cm × 76 cm) on a 1970s university building, was west-facing (location on chester street, manchester, uk m1 5gd). six of the panels were painted with a siloxane external paint formulation that contained or lacked the photoactive pigment (kindly provided by tronox, www.tronox.com). our aim was to inform the passing public about our research (an interpretation panel was affixed to the wall), and on occasion, we encouraged passers-by to participate in a longitudinal subjective assessment of the impact of titanium dioxide-containing paint on the perceived cleanliness of the panel. this engagement activity was done directly by interview and indirectly using photographs at specific times over a 44-month period. initially there was no apparent difference in the brightness of the painted panels (figure 5a ). members of the public attending a manchester science festival event (october 2014) were asked to rank the painted panels in order of cleanliness/whiteness, with 1 being most clean, and 6 being least clean (n = 18). the experiment was also conducted via a social media platform (facebook), with participants asked to assess whiteness using photographs (n = 48). the direct assessment was repeated after three years (n = 21). in all cases, the participants ranked two or three of the photocatalytic panels as the 'whitest'. in 2014, around 60% of the participants selected the three photocatalytic panels correctly. in 2017, this figure rose to 78%. after six years, the test-paint panels appeared whiter than the control panels ( figure 5b, may 2020) . the presence of the wall with its accompanying information panel at the side of the university science and engineering building provided a useful pointer to introduce visitors to some of the research ongoing in the faculty. the use of the public to assess the cleanliness of the wall proved unnecessary within a few months, when the impact of the test paint was apparent. the fact that almost all participants could discriminate between the panels after less than 12 months was also of interest. this approach might therefore be useful in the future for the assessment of test formulations. figure 5 . images of the wall at manchester metropolitan university used in the study of photocatalytic paint (panels labelled 1-6). panels 1, 3 and 6 were painted with photocatalytic paint, whilst panels 2, 4 and 5 were painted with paint that did not contain the photocatalytic agent. the image on the top (a) was taken in 2014, eight months following the application of the paint: whiteness/brightness difference between the two paint types is hard to distinguish. the lower image (b) was taken six years later (2020); panels painted with photocatalytic paint are visibly brighter compared to control paint panels. antibiotics 2020, 9, 465 9 of 12 much was learned from each event (as noted above), particularly through observation, in terms of what components participants like and engage with when discussing biofilm. in addition, quantitative evidence of engagement was derived from the 'now wash your hands' event; qualitative evidence of enjoyment and engagement was obtained from 'plaque attack', and the potential for acquisition of research data was indicated by the photocatalytic wall activity. these various outcomes informed how subsequent events for the public would take place, with more focus on design, delivery and evaluation. more recently, there has been increasing effort to ensure that these criteria for effective public engagement are met. microbiology has a particularly dynamic approach to public engagement, and many teams are now publishing the outcomes of their public engagement research in peer-reviewed journals, magazines or online. yet, in a review of public engagement activity around amr, a rich bedrock of activity was found only through personal contacts and communication rather than through a literature search [4] . it is even more important when talking to audiences about biofilms that intended messages are clear. thus, we describe in table 1 the planning of a hypothetical public engagement event designed to inform a large number of adults about biofilm and amr. our focus was on the combination of the two phenomena, which occurs, for example, when biofilms on medical devices present increased resistance to antibiotics [26] . in order to address this combined effect, it was first necessary to define the two phenomena separately. we particularly wished to avoid intrusive aspects of evaluation, relying instead on observation and other (subjective and objective) indicators from participants. we hope that this checklist may be useful for others who might wish to engage audiences with their biofilm/antibiotic research. the national biofilm information centre has recognised the importance of public engagement and is providing a hub for the dissemination of biofilm-focused outreach and engagement activities, which will enable, over time, ideas, expertise and outcomes to be shared and developed, in order to improve the effectiveness of engagement encounters for scientists and their audiences alike. we hope that our experiences in the area are of interest in this context. public engagement activities can be designed with clear aims that enable effective evaluation using both quantitative and qualitative methods. this is particularly important for complex phenomena such as biofilms and amr. the urgent need for microbiology literacy in society simfection: a digital resource for vaccination education practical microbiology in schools: a survey of uk teachers raising awareness of antimicrobial resistance among the general public in the uk: the role of public engagement activities. jac-antimicrob role of hand hygiene in healthcare-associated infection prevention the microbial contamination of mobile communication devices fitting the message to the location: engaging adults with antimicrobial resistance in a world war 2 air raid shelter spreading the message of antimicrobial resistance: a detailed account of a successful public engagement event rsph and ifh call for a clean-up of public understanding and attitudes to hygiene 99th dahlem conference on infection, inflammation and chronic inflammatory disorders: darwinian medicine and the 'hygiene' or 'old friends' hypothesis composition of in vitro denture plaque biofilms and susceptibility to antifungals dental biofilm: ecological interactions in health and disease power toothbrushes: a critical review comparison of the effect of fluoride and non-fluoride toothpaste on tooth wear in vitro and the influence of enamel fluoride concentration and hardness of enamel antimicrobial efficacy of different toothpastes and mouthrinses: an in vitro study blast a biofilm: a hands-on activity for school children and members of the public transforming a school learning exercise into a public engagement event: "the good, the bad and the algae refreshing the public appetite for 'good bacteria': menus made by microbes research methods in education photoinactivation of escherichia coli on acrylic paint formulations using fluorescent light. dyes pigment photoinduced reactivity of titanium dioxide photocatalytic construction and building materials: from fundamentals to applications effect of process parameters on the photocatalytic soot degradation on self-cleaning cementitious materials the authors declare no conflict of interest antibiotics 2020, 9, 465 antibiotics 2020, 9, key: cord-285856-0sw3wt1i authors: naesens, lieve; vanderlinden, evelien; rőth, erzsébet; jekő, józsef; andrei, graciela; snoeck, robert; pannecouque, christophe; illyés, eszter; batta, gyula; herczegh, pál; sztaricskai, ferenc title: anti-influenza virus activity and structure–activity relationship of aglycoristocetin derivatives with cyclobutenedione carrying hydrophobic chains date: 2009-02-05 journal: antiviral res doi: 10.1016/j.antiviral.2009.01.003 sha: doc_id: 285856 cord_uid: 0sw3wt1i previous studies have demonstrated that glycopeptide compounds carrying hydrophobic substituents can have favorable pharmacological (i.e. antibacterial and antiviral) properties. we here report on the in vitro anti-influenza virus activity of aglycoristocetin derivatives containing hydrophobic side chain-substituted cyclobutenedione. the lead compound 8e displayed an antivirally effective concentration of 0.4 μm, which was consistent amongst influenza a/h1n1, a/h3n2 and b viruses, and a selectivity index ≥50. structural analogues derived from aglycovancomycin were found to be inactive. the hydrophobic side chain was shown to be an important determinant of activity. the narrow structure–activity relationship and broad activity against several human influenza viruses suggest a highly conserved interaction site, which is presumably related to the influenza virus entry process. compound 8e proved to be inactive against several unrelated rna and dna viruses, except for varicella-zoster virus, against which a favorable activity was noted. previous studies have demonstrated that glycopeptide compounds carrying hydrophobic substituents can have favorable pharmacological (i.e. antibacterial and antiviral) properties. we here report on the in vitro anti-influenza virus activity of aglycoristocetin derivatives containing hydrophobic side chainsubstituted cyclobutenedione. the lead compound 8e displayed an antivirally effective concentration of 0.4 m, which was consistent amongst influenza a/h1n1, a/h3n2 and b viruses, and a selectivity index ≥50. structural analogues derived from aglycovancomycin were found to be inactive. the hydrophobic side chain was shown to be an important determinant of activity. the narrow structure-activity relationship and broad activity against several human influenza viruses suggest a highly conserved interaction site, which is presumably related to the influenza virus entry process. compound 8e proved to be inactive against several unrelated rna and dna viruses, except for varicella-zoster virus, against which a favorable activity was noted. © 2009 elsevier b.v. all rights reserved. currently available drugs for the treatment of influenza virus infections comprise the m2 ion channel blockers amantadine and rimantadine, and the neuraminidase inhibitors oseltamivir and zanamivir (de clercq, 2006; moscona, 2008) . stockpiling of oseltamivir and, to a lesser extent, zanamivir has been advocated in the context of pandemic preparedness (schünemann et al., 2007) , yet the recent isolation of oseltamivir-resistant seasonal influenza virus mutants, even from untreated patients, warrants for continued caution (lackenby et al., 2008; van der vries et al., 2008) . additional anti-influenza virus compounds should be urgently developed, having a novel antiviral target that is highly conserved amongst influenza virus (sub)types and, hence, less prone to genetic variation and resistance selection. one of the attractive therapeutic strategies would be a blockade of the viral entry into the host cell. the cellular entry process of influenza viruses has been unraveled since many years (reviewed in skehel and wiley, 2000) . a key role is being played by the viral envelope glycoprotein hemagglutinin (ha), which contains the receptor-binding site for initial attachment to the sialylated cellular receptors, and governs the receptor specificity of human versus avian influenza virus subtypes (chandrasekaran et al., 2008; nicholls et al., 2008) . in addition, after cellular uptake of the virus by endocytosis, the ha mediates the low ph-induced fusion of the viral envelope with the endosomal membrane, leading to release of the viral ribonucleoprotein in the cytosol. although the ha has been extensively studied from a biochemical and epidemiological perspective, specific antiviral drugs blocking the ha-receptor interaction remain to be clinically developed. several reports are available on the in vitro activity of small-molecule inhibitors of influenza virus fusion, which act by preventing the conformational change of the ha at low ph deshpande et al., 2001; plotch et al., 1999) . unfortunately, their development has been slow due to their inferior activity against some human influenza virus (sub)types, rapid selection for resistance and/or unsatisfactory outcome in animal models (yagi et al., 1999) . glycopeptide compounds represent a large series of natural, semisynthetic or fully synthetic compounds, which are widely recognized for their potent activity against gram-positive bacteria (nicolaou et al., 1999) . several studies have demonstrated that hydrophobic derivatives of glycopeptide antibiotics (e.g. vancomycin and eremomycin), and/or their aglycones exert antibacterial activity against glycopeptide-resistant enterococci. (cooper et al., 1996; printsevskaya et al., 2002; pace and yang, 2006) . remarkably, some of these lipophilic glycopeptide compounds were found to have inhibitory activity against coronaviruses and hiv, the latter being ascribed to inhibition of the hiv entry process (balzarini et al., 2003 (balzarini et al., , 2006 preobrazhenskaya and olsufyeva, 2006) . we here report on the chemical synthesis, anti-influenza virus activity and structure-activity relationship of novel glycopeptide compounds carrying a hydrophobic side chain on an aglycoristocetin backbone ( fig. 1) . high-yield synthesis of aglycovancomycin (1) and aglycoristocetin (2) (fig. 1 ) was performed as originally described by wanner et al. (2003) and consisted of deglycosidation of the parent antibiotics with hydrogen fluoride in anisole at neutral ph ( fig. 2) (sztaricskai et al., 2006) . the aglycones were converted into the squaric acid amide esters (4 and 5) by coupling with dimethyl squarate (3). this was followed by reaction with primary amines (6a-j) to yield the corresponding asymmetric squaric diamides (7a-g, 8a-j), using a regioselective procedure without the requirement for a protecting group strategy (tietze et al., 1991; sztaricskai et al., 2006) . the primary amines were: 6aminohexanol (6a); 6-aminohexanecarboxylic acid (6b); triglycine (6b1); dopamine (6c); n-(4-aminophenyl)piperidine (6d) and 4phenyl-benzylamine (6e). based on the observation that compound 8e displayed favorable anti-influenza virus activity (see below), subsequent modifications were performed to study the impact of an increasing steric bulk in the rigid aromatic side chain of 7f-g and 8f-h, which were prepared with 1-naphthylamine (6f), 4-aminoterphenyl (6g) or 2-aminoanthracene (6h). it has been shown that introduction of hydrophobic substituents into glycopeptide antibiotics enhances their activity against glycopeptide-resistant bacteria (cooper et al., 1996; printsevskaya et al., 2002; pace and yang, 2006) , but, unfortunately, these products have lower water-solubility. to improve solubility, the squaric acid amide ester 5 was reacted (sztaricskai et al., 2007b) with d-glucosamine (6i) or d-galactosamine (6j), resulting in the asymmetric squaric diamides 8i and 8j, respectively. in these products, the carbohydrate moiety is linked to the aglycone in an unusual manner, i.e. through a cyclobutandione moiety, and not directly through one of the hydroxyl groups, as in the parent glycopeptide antibiotics. the structure, reaction yield and physico-chemical data for the aglycones, their squaric acid amide esters and corresponding asymmetric diamides, are summarized in table 1 . the homogeneity of all compounds was checked by tlc and hplc, and the structures were confirmed by mass spectrometry. (2) were first converted into their squaric acid amide esters (4 and 5, respectively), followed by conversion to the asymmetric squaric diamides (7a-g and 8a-j, respectively). see table 1 for the structures of the r1 group, as present in the primary amines 6a-j and the final products 7a-g and 8a-j. (2) into their squaric acid amide esters (4 and 5, respectively), these were converted to the asymmetric squaric diamides (7a-g, derived from aglycovancomycin, and 8a-j, derived from aglycoristocetin). b hplc conditions: instrument: waters 600 with uv230nm detection; column: lichrospher rp-8 (4 mm × 250 mm; 10 m); injection volume: 20 l (corresponding to 2 g compound); solvents: table 2 , several asymmetric squaric diamides derived from aglycoristocetin exerted marked activity against influenza virus, the most potent compounds being the phenylbenzyl derivative 8e [average antiviral ec 50 : 0.4 m; selectivity index (si), defined as the ratio of mcc to ec 50 : 50]; the hexanol deriva-tive 8a (ec 50 : 1 m; si: 14) and the naphthyl derivative 8f (ec 50 : 1.4 m; si: 10). their activity was 2-to 5-fold higher than that of the squaric acid amide ester of aglycoristocetin 5 (ec 50 : 2.4 m; si: 42). an intermediate activity (ec 50 : 5 m) was observed for the triglycyl derivative 8b1 which, surprisingly, was comparably active as unsubstituted aglycoristocetin 2. the 3,4-dihydroxybenzyl derivative 8c and the d-galactosamine derivative 8j were active against two of the three influenza virus strains tested, and the derivatives containing carboxypentyl (8b) and d-glucosamine (8i) substituents had activity against only one virus strain. the compounds carrying 4-aminophenylpiperidine (8d), terphenyl (8g) and anthracene (8h) substituents were completely inactive. thus, the intrinsic antiinfluenza virus activity of aglycoristocetin is markedly increased by squaric acid amide coupling and addition of a hydrophobic side chain, with the phenylbenzyl group being the optimal substituent. the favorable effect of this side chain appears to depend on different factors, namely: neutral charge (the alcoholic aliphatic derivative 8a is clearly more active than the corresponding carboxypentyl compound 8b) and steric bulkiness (8e and 8f are active while the more bulky compounds 8g and 8h are not). the aglycoristocetin backbone structure was shown to be critical for inhibition of influenza virus, since no activity was observed for compound 7e, which represents the aglycovancomycin analogue of 8e. aglycoristocetin and aglycovancomycin both contain a central heptapeptide core and nonproteinogenic phenolic amino acids, i.e. ␤-hydroxytyrosine (c and e units), 4-hydroxyphenylglycine (b and d units) and 3,5-dihydroxyphenylglycine (a unit) (fig. 1) . the main structural differences between both glycopeptide aglycones are as follows (fig. 1) : (i) whereas aglycovancomycin has five aromatic rings (a-e) and two known amino acids (l-aspartic acid and n-methyl-d-leucine), aglycoristocetin has seven aromatic moitable 3 cytotoxicity of selected aglycoristocetin derivatives in human and animal cell lines. a . cytotoxic concentration ≥100 >100 100 >100 a human embryonic lung (hel) fibroblasts; human cervix epithelial (hela); african green monkey kidney (vero); and crandell feline kidney (crfk) cells; nd: not done. b the cytotoxic concentration was defined as the minimum cytotoxic concentration (mcc) or 50% cytotoxic concentration (cc50); cf. legend to table 2. eties (a-g); (ii) the additional f and g rings of aglycoristocetin are interconnected via a diphenylether linkage (constituting the ristomycinic acid moiety); (iii) aglycoristocetin lacks the chloro substituents on the c and e rings, present in aglycovancomycin; (iv) the c-terminal carboxyl function is free in aglycovancomycin, but contains a methyl ester in aglycoristocetin and (v) aglycoristocetin has a primary amine function, whereas aglycovancomycin contains a secondary amine group (crowley et al., 2004) . at present, we cannot speculate on which of these structural components explain the antiviral specificity of the aglycoristocetin derivatives. our basic test panel of influenza viruses contained one chimeric virus (a/x-31; h3n2 subtype), one a/h3n2 virus and one b virus strain (table 2) . when the lead compound 8e was further evaluated for activity against a/h1n1 (strain a/puerto rico/8/34), its antiviral ec 50 value was 0.12 ± 0.04 m, which is in the same range as that for the a/h3n2 and b strains. determination of its cytostatic activity in mdck cells, using a cell counting assay, revealed an ic 50 value of 67 ± 19 m. thus, 8e emerged as a potent inhibitor of influenza virus replication, with broad activity against different (sub)types and favorable selectivity. the glycopeptide compounds were evaluated for activity against other viruses besides influenza virus. none of the following rna viruses was found to be significantly inhibited by any of these glycopeptides, as evaluated by cpe or plaque reduction assay: feline coronavirus [examined in crandell-rees feline kidney cells]; vesicular stomatitis virus, coxsackie b4 virus and respiratory syncytial virus [performed in human epithelial hela cells]; parainfluenza-3 virus, reovirus-1, sindbis virus and punta toro virus [tested in african green monkey vero cells]. in human embryonic lung fibroblast cells infected with various dna viruses, the only glycopeptide displaying some activity was compound 8e, with antiviral ec 50 values of 10 m (herpes simplex virus type 1; wild-type or thymidine kinase-deficient); 6 m (herpes simplex virus type 2); >100 m (cytomegalovirus) and 12 m (vaccinia virus), and a selectivity index of 10-17. of note, 8e was found to be highly active against varicella-zoster virus (vzv; wild-type or thymidine kinasedeficient), with an antiviral ec 50 value of 0.55 m and a selectivity index of 180. the diverse antiviral assays performed in human or animal cell lines permitted to obtain a more detailed insight into the cytotoxicity of the aglycoristocetin derivatives selected from the influenza virus experiments (table 3 ). all compounds were either not or minimally cytotoxic at a concentration of 70-100 m. the cytotoxicity values for the lead compound 8e were in the same range as previously obtained in mdck cells. some glycopeptides in this study were previously evaluated for antibacterial activity (sztaricskai et al., 2006) , with 8e emerging as a highly active compound. our present anti-influenza virus data thus agree with the view that hydrophobic substitution has a positive impact on the pharmacological (i.e. antibacterial and antiviral) activities of glycopeptide compounds (printsevskaya et al., 2002; balzarini et al., 2003 balzarini et al., , 2006 . with regard to the antiviral mode of action, time-of-addition studies suggested that 8e blocks the viral entry process, since optimal anti-influenza virus activity was obtained when the compound was added to mdck cells 30 min prior to or simultaneously with virus infection. a detailed analysis is currently ongoing to determine the effect of 8e on the virus-receptor interaction (i.e. binding of the viral ha to the sialic acid terminus of cell surface glycans), endocytosis or membrane fusion (i.e. fusion of the viral envelope with the endosomal membrane). whatever the precise mode of action, the subtype-independent activity of 8e provides strong support that the interaction site of 8e is highly conserved amongst human influenza virus strains. this is consistent with our observation that influenza virus fully retained its sensitivity to 8e after eleven sequential virus passages in mdck cells in the presence of 8e (at concentrations up to 25 m). within human influenza virus ha sequences, only few residues are fully conserved, in particular in the receptor-binding site and fusion peptide (skehel and wiley, 2000) . the aglycoristocetin compounds described here and represented by the lead compound 8e are not the first glycopeptides reported to have activity against influenza virus. in 1993, naruse et al. reported on the isolation, characterization and anti-influenza virus activity of two kistamicin antibiotics (naruse et al., 1993) . similarly to our compounds, both kistamicins showed strong activity against influenza virus and low activity against herpes simplex virus type 1. the kistamicins were reported to be inactive in hiv syncytium assays (naruse et al., 1993) . the observation that the anti-influenza virus activity of the kistamicins was higher when a lipophilic substituent was present at the terminal amine function, is reminiscent of our findings with the aglycoristocetin derivatives. in conclusion, the broad and robust anti-influenza virus activity of the aglycoristocetin derivatives described in this study creates a new avenue for the development of anti-influenza virus agents with a novel mode of action. the relatively narrow structure-activity relationship points to a highly specific interaction with the antiviral target, which is probably related to interaction of the influenza virus hemagglutinin with its cellular receptor. further studies to unravel the structure-activity relationship and precise mode of action are underway in our laboratories. antiretroviral 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for the formation of drug biopolymer conjugates synthesis of squaric acid ester amides and diamides fatal oseltamivir-resistant influenza virus infection a new and improved method for deglycosidation of glycopeptide antibiotics exemplified with vancomycin, ristocetin, and ramoplanin development of anti-influenza virus drugs. i. improvement of oral absorption and in vivo anti-influenza activity of stachyflin and its derivatives this study was supported by grants from the fonds voor wetenschappelijk onderzoek vlaanderen (fwo no. 9.0188.07), the international consortium for anti-virals (icav) and the hungarian national scientific research foundation (no. otka t 46744). we thank leentje persoons, frieda de meyer and vicky broeckx for dedicated assistance, and dr. sándor kéki (department of applied chemistry, university of debrecen) for recording the mass spectra. we thank dr. t. cihlar (gilead sciences, usa) for the generous gift of oseltamivir carboxylate. key: cord-262950-zv6qerhg authors: reinert, kassidy s.; higbee, thomas s.; nix, lyndsay d. title: creating digital activity schedules to promote independence and engagement date: 2020-06-19 journal: behav anal pract doi: 10.1007/s40617-020-00437-8 sha: doc_id: 262950 cord_uid: zv6qerhg photographic activity schedules have been demonstrated to be effective in helping individuals with autism and other developmental disabilities learn how to complete both simple and complex sequences of activities without prompting from adults. although the majority of research studies demonstrating the effectiveness of activity schedules have used schedule books composed of static printed pictures attached to physical pages, recently researchers have begun to demonstrate the effectiveness of technology-based activity schedules. in the current article, we provide a task analysis for creating both simple and complex digital activity schedules using google slides, a freely available, web-based technology that operates on a variety of digital platforms. we also provide suggestions for how behavior analysts can train parents to use this technology with their children using telehealth procedures. ). these studies demonstrate that activity schedules promote independence, increase learner engagement with appropriate activities, and decrease reliance on prompts. therefore, these tools are ideally suited for situations, such as the current covid-19 crisis, where access to direct, professional-led learning may be reduced and clients may be provided with longer periods of "downtime" than under typical circumstances. activity schedules are an attractive tool for promoting independence not only because of their effectiveness but also because of the broad range of individuals with whom they can be used and the wide array of skills they can be used to promote. they require relatively few prerequisite skills and conditions in order to be effective (e.g., picture-object correspondence, acceptance of physical prompts, identified reinforcers) and can be used to teach sequences of behavior as simple as independent play sequences (macduff et al., 1993) and as complex as group social games such as hide-and-seek (akers et al., 2018) . importantly, researchers have demonstrated that parents can be taught, via technology, to implement activity schedule teaching procedures with high degrees of fidelity (gerencser, higbee, akers, & contreras, 2017) . to date, most activity schedules used in published studies have been composed of three-ring binders with pictures attached to individual pages or strips of pictures on a single page. although inexpensive, binder-or paper-based schedules editor's note this manuscript is being published on a highly expedited basis, as part of a series of emergency publications designed to help practitioners of applied behavior analysis take immediate action to adjust to and mitigate the covid-19 crisis. this article was submitted on april 3, 2020, and received final acceptance on april 6, 2020. the journal would like to especially thank dr. thomas szabo for his expeditious review of the manuscript. the views and strategies suggested by the articles in this series do not represent the positions of the association for behavior analysis international or springer nature. may have some disadvantages, such as being cumbersome to transport (carlile, reeve, reeve, & debar, 2013) and, perhaps more importantly, potentially socially stigmatizing, as same-aged peers would likely not be carrying around books during activities (giles & markham, 2017) . given technological advances that have made portable electronic devices, such as tablet computers, more readily available to teachers and families of individuals with disabilities, there may be advantages to using digital schedules that could be displayed on these devices. first, scanned or photographic images of activities could be easily moved around within activity schedules, reducing the cost and effort of printing and laminating images for inclusion in binder-based or single-page printed schedules. second, digital schedules could easily be shared across multiple devices. for example, copies of the schedule could be updated by a teacher or therapist and then e-mailed to a parent for use at home. finally, tablet computers are now ubiquitous in school, work, and home settings, thus reducing potential stigmatization for digital activity schedule users. multiple researchers have investigated the effectiveness of various forms of digital activity schedules delivered on electronic devices, including computers running microsoft powerpoint (rehfeldt, kinney, root, & stromer, 2004) , ipods to increase on-task behavior (carlile et al., 2013) , video clips to increase dramatic play (dauphin, kinney, & stromer, 2004) , ipads to increase time on task and decrease transition time during centers (gourwitz, 2014) , and ipads to promote completion of leisure activities (giles & markham, 2017) . one published study has also indicated that, for some participants, digital activity schedules may be preferred over binderbased schedules (giles & markham, 2017) . although further research on the use of digital activity schedules is certainly warranted, a sufficient body of research exists to demonstrate the potential benefits of this technology. given the portability of digital activity schedules and the potential for behavior analysts to be able to design digital activity schedules and transmit them electronically to parents or caregivers for use with their children at home, we believe that they are ideally suited to the current therapeutic environment caused by the covid-19 pandemic, which limits direct contact between behavior analysts and the clients and families with whom they work. thus, the purpose of this article is to provide a detailed task analysis that both behavior analysts and parents can use to create and modify digital activity schedules using google slides, a freely available, web-based program that works on a variety of digital devices and platforms. although detailed descriptions of how to create and build independence using activity schedules are available elsewhere (e.g., higbee & brodhead, 2016; higbee & sellers, 2017; mcclannahan & krantz, 1999) , a brief summary of how to select activities for inclusion in a digital activity schedule and standard prompting/teaching techniques is included here. we refer the reader to the cited papers for more detailed descriptions and instructions. specific activities to be included in a beginning activity schedule, including a digital one, should be moderately preferred, close-ended (i.e., have a clear beginning and end), relatively brief, and already independently performed by the learner, as the focus during initial activity schedule training is on how to follow the schedule rather than on the activities themselves (higbee & sellers, 2017) . beginning activity schedules are usually composed of at least two to three activity pages plus a terminal reinforcer page (typically a small amount of a preferred edible) at the end. additional activities can be added as the learner demonstrates mastery of the schedule to form progressively longer response chains. the sequence of activities should be changed frequently to ensure that the learner's behavior comes under the control of the pictures displayed as opposed to becoming a sequence of rote behaviors under proprioceptor control of sensations repeated in a performance chain. activity schedules can be used in multiple environments. however, beginning play/leisure activity schedules often are used at a table or desk that is large enough to both hold the schedule and provide enough room to complete the activities (the floor could also be used in the absence of a desk or table). activity materials are typically placed on a shelf near the desk/table. they could also be placed directly on the table if it is large enough to hold all materials and still have a clear work space to complete activities. alternatively, materials could be placed on the floor near the table. when learners are first beginning to use activity schedules, the idea is to have the materials close at hand to reduce travel time and the potential for distraction. once learners have mastered the basic components of activity schedule following, materials can be placed in their natural locations. learners are taught, through a procedure called "graduated guidance," described in the next section on prompting procedures, to follow the activity schedule. the following sequence of behaviors constitutes "following the schedule": 1. retrieve the schedule (obtain the tablet or other digital device) and place it on the table/floor where activities will be completed. open the schedule file/program (steps 1 and 2 may be completed by a parent or teacher for a digital schedule, depending on the learner's level of familiarity with the technology). 3. touch the picture of the activity (an observing response). 4. obtain the materials necessary for completing the activity (e.g., retrieve the pictured puzzle from a shelf). 5. complete the activity. 6. return the materials back to their original location. 7. "turn the page" on the digital schedule to display the next activity by touching or clicking on the arrow in the bottom-right corner of the screen. 8. repeat steps 3-7 until reaching the terminal reinforcer page and consuming the reinforcer. 9. return the digital device to its original location or close the program. in an effort to reduce dependence on adult-provided verbal prompts and instructions, learners are taught to follow activity schedules exclusively via physical prompts delivered from behind the learner, so as not to block the learner's view of the relevant visual stimuli that should control their behavior (mcclannahan & krantz, 1999) . the only verbal instruction given to the learner should be the initial instruction to begin completing the schedule (e.g., "it's time to do your activity schedule. here you go!"). after that, the person assisting the learner to follow the schedule should not provide any additional verbal instructions, verbal prompts, or conversation until the schedule is completed (unless one of the included activities is a social activity during which verbal interaction would be appropriate). the amount of physical prompting provided will depend on each individual learner's abilities but will often begin with hand-over-hand guidance that should be provided in a way that allows the learner to complete the schedule with as few errors as possible. this physical guidance should be faded as quickly as possible to avoid prompt dependence. a typical fading sequence would begin with hand-over-hand guidance that is progressively faded to physical prompts at the wrist, forearm, elbow, and shoulder, followed by gradually increased physical distance between the prompter and the learner. we have found that light physical prompts from behind at the shoulders are particularly effective for guiding learners back and forth between the schedule and the activity materials. fading can take place dynamically within sessions or can be scripted across sessions. one practical method for prompt fading that has been particularly useful when parents are the primary implementers is that used by gerencser et al. (2017) , where test sessions are periodically run using a 5-s prompt delay procedure to determine the steps a learner can complete independently. prompts that the learner needed to complete the task are recorded on a data sheet, which then serves as a teaching guide for sessions until the next test session is conducted (see the appendix, fig. 28 , for a sample data sheet). behavior analysts who have the capacity to view sessions live through videoconference technology could also provide parents with fading suggestions in real time. when learners make errors, the type of error will determine how the implementer/prompter should respond. if the learner begins to drift off task or begins to engage in stereotypy with schedule materials, the implementer/prompter should simply interrupt this behavior and physically redirect the learner to complete the activity correctly. however, if the learner obtains the incorrect materials after touching the picture representing those materials, he or she should be redirected back to the schedule, physically prompted to touch the picture of the materials again, and physically guided to obtain the correct materials. this helps ensure that learner behavior comes under the control of the schedule. once learners have mastered following basic activity schedules with brief, close-ended activities, more complex activities can be introduced. for example, implementers can add choice pages in which the learner can select from two or more available activities. on a close-ended activity schedule that a learner previously mastered, choice pages could be added to the schedule to replace one or more of the close-ended activities. learners can also be taught to set and respond to digital timers using visual cues in order to include open-ended activities in the digital schedule. red circles representing the number of minutes for the activity and a green circle representing the start button are placed below the picture of the open-ended activity. the minute button on the digital timer is also colored red and the start/stop button colored green. the learner is physically prompted to touch each circle below the picture and the corresponding colored button on the timer to set and start the timer. responding to these more complex activity schedule pages can often be taught via graduated guidance within activity schedule sessions. if a learner requires more practice, modeling and teaching sessions with timers and choice pages could occur outside of activity schedule sessions (higbee & sellers, 2017; mcclannahan & krantz, 1999) . learner performance can be measured by scoring steps from the schedule-following sequence that were performed independently by the learner. a sample data sheet is included in the appendix, fig. 28 . whereas collecting data during each teaching session would be ideal during the initial stages of learning, gerencser et al. (2017) suggest using test sessions that may provide sufficient data to make decisions about prompt levels. an example of the data sheet that is similar to the one used by gerencser et al. is provided in the appendix, fig. 29 . also, when parents are implementing activity schedules, behavior analysts could score performance viewed live through videoconferencing technology or via recorded sessions sent electronically by parents. the following task analysis uses the web-based program google slides to create digital activity schedules. google slides is a freeware program that works on a variety of digital devices and operating systems. more information about google slides can be found at https://www.google.com/ slides/about/. a flowchart of essential steps in the task analysis is provided in the appendix, fig. 30 , to guide the reader and assist with troubleshooting. 1. open a web browser and sign in to your google account. 2. navigate to https://docs.google.com/presentation. 3. create a new blank presentation by clicking the multicolored plus sign in the navigation bar near the top of the page. 4. click "untitled presentation" in the top-left corner and type "activity schedule template." activity schedule setup and cover (figure 1) 1. click "file" and navigate to "page setup" near the bottom of the list. 2. resize the page by clicking "widescreen 16:9." select "custom" and change the dimensions to 5.5 × 8.5 in. click "apply." 3. click "background" on the toolbar and select a desired color for the schedule background. select "add to theme" and then click "done." 4. select the subtitle text box and press the "delete" key. 5. click on the title text box. blue squares should appear on the text box, as shown in fig. 2 . resize the title text box by dragging down the bottom-center square to make a large rectangle centered on the page. a. google slides provides red guide lines (fig. 2 ) that aid with centering shapes, objects, and so on. these guide lines pop up when an item is centered horizontally and/ or vertically within a slide or with adjacent items. 6. select the title text box and change the background to white by clicking the fill color icon (fig. 3) . 7. select "click to add title" and type "student's name." student‛s name next next 8. while the title text box is selected, click on the align icon (fig. 4) . center the text horizontally by clicking the center icon and vertically by clicking the middle icon. 9. select the shape tool and select the right arrow icon, as displayed in fig. 5 . draw in the bottom-right corner of the page. 10. double-click on the arrow and type "next" in the center of the arrow. the activity schedule cover should look like fig. 1 . creating close-ended activity pages ( figure 6 ) and the terminal reinforcer page (figure 7) 1. create a new blank page by clicking on the last page in the left column and pressing the "enter" key. 2. delete all text boxes. 3. insert a large white square in the center of the page. 4. insert a picture of a close-ended activity using the insert image icon (see fig. 8 ) to import desired pictures of activity schedule toys. 5. center and resize the picture to fit in the white square area. 6. repeat steps 1-5 to create multiple close-ended activity pages and one terminal reinforcer page. the close-ended pages of the activity schedule should look like fig. 6 , and the terminal reinforcer page should look like fig. 7 . 7. after creating all pages in a schedule, move the terminal reinforcer page to the last page in the schedule. creating simple navigation between slides 1. navigate to the cover page. 2. select the shape tool ( fig. 9) and draw a large rectangle over the entire page. 3. right-click on the rectangle. navigate to "order," then "send backward." now only the next arrow should be visible on the page. 4. select the next arrow and click the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. click on "slides in this presentation." select "next slide" and click "apply." this will now make it so clicking or pressing the next arrow during a presentation transitions to the next slide. a. please note that the pop-up drop-down menu may run below the bottom of the browser page and may not be fully visible. in order to view all link options, resize the object or move to a higher location on the page. perform the link operation and then return to the previous size and location. 5. select the rectangle and navigate to the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. click on "slides in this presentation," select the current slide number, and click "apply." this will disable all clicks or presses anywhere on the page other than a click on the arrow. 6. click on the large rectangle and then on the color fill and border color icons (fig. 11 ). change the color fill and border color to transparent. 7. copy the large rectangle from the cover page and paste on additional close-ended and terminal reinforcer pages. 8. then copy the "next" arrow from the cover page and paste it on additional close-ended and terminal reinforcer pages. 9. completed close-ended slides can also be replicated using copy and paste. links will continue to work. to edit the copied slides, select the large transparent rectangle and move it out of the way in order to edit or replace pictures. after editing, return the large transparent rectangle to its original position. 10. go to the present icon (fig. 12) , located in the top-right corner of the toolbar, to view and navigate through the slides. a. navigate through the presentation by clicking on the "next" arrows. they should advance you to the next slide in the sequence. i. if an arrow does not advance correctly, check the links by clicking on the arrow. when clicked on, each arrow should display a white link bar below with the words "next slide." if the slide linked to the arrow is incorrect, click "remove link" and return to step 4 in the section "creating simple navigation between slides." ii. if there is no link, return to step 4 in "creating simple navigation between slides." b. after all arrow transitions are working correctly, restart the slideshow. check that no other transitions occur when clicking elsewhere on the screen (anywhere other than the arrows). i. if transitions do occur, return to step 5 in "creating simple navigation between slides." creating choice pages (figure 13) 1. create a new blank page by clicking on the previous page in the left column and pressing the "enter" key. creating navigation for choice pages 1. in the left navigation bar, navigate to the last choice page with a large picture in the lower rectangle (fig. 18 ) and press the "enter" key to create a blank page. title this new slide "blank." 2. navigate to the first choice slide with an empty lower rectangle (fig. 13 ). there should not be a "next" arrow on this page. 3. draw a large rectangle over the entire page using the shape tool (fig. 9 ). 4. right-click on the rectangle. navigate to "order" and then select "send to back." now only the four toy pictures should be visible on the page. 5. click on the large rectangle and navigate to the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. click on "slides in this presentation" and select the current slide number. click "apply." 6. click on the large rectangle and then on the color fill and border color icons (fig. 11) . change the color fill and border color to transparent. 7. right-click on the rectangle and copy it. 8. navigate to the remaining choice pages and paste the transparent rectangle on all four pages. a. to ensure correct navigation, click on the transparent rectangle on each subsequent choice page. the rectangle on each slide should display a white link bar on the lower left corner with the current slide number. if the slide linked to the rectangle is incorrect, click "remove link." return to step 5 in the section "creating navigation for choice pages." 9. navigate to the first choice slide with an empty lower rectangle (fig. 13) . 10. click on one toy picture and click on the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. click on "slides in this presentation" and select the corresponding slide number that has the identical toy picture enlarged in the lower half of the page. click "apply." 11. repeat step 10 for the remaining three toy pictures. a. to ensure correct navigation, click on each picture in the first choice slide. when clicked on, each picture should display a white link bar below with the corresponding slide number (see the flowchart in the appendix, fig. 30 ). if the slide linked to the small picture is incorrect, click "remove link." return to step 10 in the section "creating navigation for choice pages." 12. navigate to the "student's name" page (on the cover of the presentation). 13. right-click on the "next" arrow and copy it. 14. in the left navigation bar, select the second choice page (the first slide with a large toy picture in the lower rectangle; fig. 18 ) and paste the arrow. 15. select the "next" arrow and click the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. remove the previous link by clicking on the "x." click on "slides in this presentation." select the "blank" slide and click "apply." this will now make it so clicking or pressing the "next" arrow during a presentation transitions to the next slide. 16. right-click on the "next" arrow and copy it. 17. paste a copy of the arrow on the remaining three choice pages. each of these pasted arrow's navigation should automatically be linked to transition to the blank slide. a. to ensure correct navigation, click on the "next" arrow on each subsequent choice page. when clicked on, each next arrow should display a white link bar below with the blank slide number. if the slide linked to the arrow is incorrect, click "remove link." return to step 15 in the section "creating navigation for choice pages." 18. go to the present icon (fig. 12) , located in the top-right corner of the toolbar, to view and navigate through the choice slides. a. if there are errors with transitions from the initial choice slide to subsequent choice pages, refer to step 11 in the section "creating navigation for choice pages." b. if there are errors with the transition arrows on the subsequent choice pages, refer to step 17 in the section "creating navigation for choice pages." c. after all arrow and picture transitions are working correctly, restart the slideshow. check that no other transitions occur when clicking elsewhere on the screen (anywhere other than the arrows and the first choice-page pictures). if transitions occur, return to step 8 in "creating navigation for choice pages." three-min timed activity pages (figure 19) a. click "file" and navigate to "page setup" near the bottom of the list. b. resize the page by clicking "widescreen 16:9." select "custom" and change the dimensions to 5.5 × 8.5 in. click "apply." c. navigate to the "activity schedule template" slideshow. 17. click the insert image icon (fig. 8) , resize, and place a picture of an open-ended/timed activity on the page above the circles (as shown in fig. 19 ). creating navigation for a 3-min timer page 1. draw a large rectangle over the entire page using the shape tool (fig. 9 ). 2. click on the large rectangle and navigate to the insert link icon (fig. 10) in the toolbar. a white pop-up bar will appear on the screen. click on "slides in this presentation" and select the current slide number. click "apply." 3. click on the large rectangle and then on the color fill and border color icons (fig. 11) . change the color fill and border color to transparent. 4. create smaller dots (circles) on the corresponding timer buttons (fig. 19) . a. select the shape tool ( fig. 9) and draw one small button-sized red circle. (pressing shift while drawing the circle will keep it perfectly round.) rightclick on the circle and then copy and paste it once. use the color fill icon (fig. 3) to change the second dot to green. i. move the red dot on top of the timer's minute button. ii. move the green dot on top of the timer's start button. 5. right-click the timer page in the left navigation bar and copy it. 6. paste four more timer pages into the left navigation bar (similar to fig. 17) . 7. create a new blank page by clicking on the previous page (the final timer page) in the left navigation bar and pressing the "enter" key. 8. navigate to the first timer slide. 9. right-click on the green button dot. navigate to "order," then "send to back." 10. select the red button dot. navigate to the insert link icon (fig. 10) in the toolbar. click on "slides in this presentation" and select "next slide." click "apply." 11. repeat steps 9-10 for the next two timer slides. 12. on the fourth timer slide, right-click on the red dot. navigate to "order," then "send to back." 13. select the green button dot. navigate to the insert link icon (fig. 10) in the toolbar. click on "slides in this presentation" and select "next slide." click "apply." 14. navigate back to the second timer slide. select the text box icon (fig. 14) , create a text box, and type "1:00." place the time text box over the timer screen. adjust the text box size, font size, and color fill as needed. 15. select the text box with "1:00." copy the text box and paste it into the remaining timer pages. edit the text boxes on each subsequent timer page to increase the time shown by 1 min (fig. 23) . edit the timer text boxes on the fourth and fifth timer pages to both say "3:00." 16. after copying and editing the text boxes, right-click the timer text box on each page and click "order," then "send to back." 17. select the fifth timer slide in the left navigation bar. 18. click on the "insert" menu ( fig. 24 ) and select "video." 19. a youtube search bar will appear. type in "3 minute timer." choose the timer and click the "select" button. 20. a "format options" bar will appear on the right when the video is inserted. select "autoplay when presenting," as seen in fig. 25 . 21. select the "next" arrow from the cover page of the presentation (with "student's name"). copy and paste the arrow in the bottom right of the video page (fig. 26) . 22. after the timer video page, create a blank slide to continue making the schedule. a. to finish the schedule, see the section "creating a new schedule/modifying the schedule template." 23. go to the present icon (fig. 12) , located in the top-right corner of the toolbar, to view and navigate through the timed activity slides. a. navigate through the presentation by clicking on the timer dots in sequence and the "next" arrow. each click should advance to the next slide in the sequence. i. if the slides do not advance correctly, check the links by clicking on the linked object. when clicked on, each linked object should display a white link bar below with the words "next slide." if the slide linked to the object is incorrect (or missing), click "remove link" and return to the step corresponding to the specific object: fig. 16 background button 1) red dot: step 10 in the section "creating navigation for a 3-min timer page" 2) green dot: step 13 in the section "creating navigation for a 3-min timer page" 3) next arrow: step 21 in the section "creating navigation for a 3-min timer page" b. after all transitions are working correctly in sequence, restart the slideshow. check that no other transitions occur when clicking elsewhere on the screen (anywhere other than the linked objects). i. if transitions occur, check the following: 1) ensure that the transparent rectangle is linked correctly. if it is not, return to step 2 in the section "creating navigation for a 3-min timer page." 2) if an incorrect object is creating a transition, exit the slideshow and navigate to the slide with that object. right-click on the object, select "order," and then "send to back." to create a new schedule, copy and paste the template slide sets into a new google slides presentation. the template sequences will maintain links and other properties. for example, to create one choice activity, copy all five slides of the choice page. this task analysis will assist in creating a template that clinicians can then use to create client-specific schedules. each schedule should end with a terminal reinforcer that is fig. 30 ). to replace pictures in any of the pages, select the large transparent rectangle and move it out of the way. then edit or replace pictures and place the large transparent rectangle back in place. to test and ensure all pages and features are working correctly, we suggest selecting the present icon (fig. 12) to navigate and interact with the slides as the client would to check for errors. to assist with following the activity schedule template sequence, we provide a flowchart example in the appendix, fig. 30 . there are various options for sharing activity schedule files with caregivers and clients. one way is to send the caregivers a link to the activity schedule file. to create a link, select the yellow "share" button ( fig. 27) in the topright corner. a pop-up menu will appear that provides sharing options, including view-only or editable access. select "get shareable link" and then e-mail this link to the family/client. other examples of how to share the activity schedule include creating a google drive folder with multiple schedule variations or sharing it with other instructional materials using google classroom. for all sharing options, learners will need to view the activity schedules in the present form or the slideshow view. to access the presentation on mobile devices or tablets, they will need to download the google slides app. researchers have demonstrated that photographic activity schedules can be an effective tool to promote independence and reduce the need for adult prompts across a variety of behaviors and for many different types of learners. whereas much of this body of research has investigated the use of binder-based or single-page paper activity schedules, in recent years, researchers have demonstrated that technology-based digital schedules can also be effective and, in some circumstances, preferred by learners (giles & markham, 2017) . digital activity schedules have multiple potential advantages that make them well suited to situations such as the current covid-19 crisis, during which face-to-face contact between behavior analysts and their clients and families may be reduced or eliminated. another possible advantage includes the relative ease with which they can be modified and the potential for behavior analysts to create and disseminate digital activity schedules electronically. the task analysis included in this article may be a useful tool as behavior analysts create and disseminate digital activity schedules. conflict of interest the authors have no known conflicts of interest to disclose. informed consent as this is a technical article, no human participants were involved in the project. thus, no informed consent was necessary. directions: collect data on the learner's performance. correct responses will be scored as a plus (+) and incorrect response or responses you provided physical supports will be scored as a minus (-). retrieves schedule step 27 steps 1-5 steps 1-10 step 1 steps 2-11 steps 12-18 steps 1-10 steps 1-10 an evaluation of group activity schedules to promote social play in children with autism using joint activity schedules to promote peer engagement in preschoolers with autism the use of linked activity schedules to teach children with autism to play hide-and-seek using activity schedules on the ipod touch to teach leisure skills to children with autism. education and treatment of children effects of a photo activity schedule book on independent task changes by students with intellectual disabilities in community job sites using videoenhanced activity schedules and matrix training to teach sociodramatic play to a child with autism evaluation of interactive computerized training to implement photographic activity schedules with children with autism spectrum disorder comparing book-and tablet-based picture activity schedules: acquisition and preference ipads for students with asd: comparing delivery modes for visual activity schedule (doctoral dissertation promoting independence, verbal behavior, and social skills in individuals with autism through activity schedules and script fading handbook of social skills and autism spectrum disorder: assessment, curricula, and interventions teaching children with autism to use photographic activity schedules: maintenance and generalization of complex response chains activity schedules for children with autism: teaching independent behavior creating activity schedules using microsoft® powerpoint® publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-295543-nj4a640t authors: castañeda-babarro, arkaitz; arbillaga-etxarri, ane; gutiérrez-santamaría, borja; coca, aitor title: physical activity change during covid-19 confinement date: 2020-09-21 journal: int j environ res public health doi: 10.3390/ijerph17186878 sha: doc_id: 295543 cord_uid: nj4a640t background: the lockdown and social distancing caused by covid-19 may influence common health behavior. the unprecedent worldwide confinement, in which spain has been one of the most affected—with severe rules governing confinement—may have changed physical activity (pa) and sedentary habits due to prolonged stays at home. purpose: the aim of this study is to evaluate how self-reported pa and sedentary time (st) have changed during confinement in the spanish population. methods: 3800 healthy adults (age 18–64 years) residing in spain answered the international physical activity questionnaire short (ipaq-s) twice between 23 march and 1 april (confinement). data analysis was carried out taking into consideration meeting general pa recommendations before confinement, age and gender. results: self-reported pa decreased significantly during confinement in our sample. vigorous physical activities (vpa) and walking time decreased by 16.8% (p < 0.001) and 58.2% (p < 0.001), respectively, whereas st increased by 23.8% (p < 0.001). the percent of people fulfilling the 75 min/week of vpa recommendation decreased by 10.7% (p < 0.001) while the percent of people who reached 150 min/week of moderate activity barely changed (1.4%). the group that performed the most vpa before confinement showed the greatest decrease (30.5%, p < 0.001). men reduced time in vpa more than women (21% vs 9%, respectively) who even increased time in moderate pa by 11% (p < 0.05) and reported less increase in st than men (35% vs 25.3%, respectively). conclusion: the spanish adult population, especially young people, students and very active men, decreased daily self-reported pa and increased st during covid-19 confinement. on 11 march 2020, the world health organization (who) [1] declared a global pandemic caused by severe acute respiratory syndrome coronavirus (sars-covid-2), which has become a public health emergency of international concern. during its first phase of expansion outside china, italy and spain were the most affected countries reporting most cases and deaths. thus, they were the first nations to declare a state of emergency in europe. in spain it was declared on 17 march and the government ordered a lockdown to restrict travel and cancel non-essential services in order to stop the spread of coronavirus disease (covid-19) [2] . social distancing and confinement are fundamental in tackling the spread of coronavirus. however, the ongoing lockdown across the country has no precedent and it is unknown how this may affect the general population's health and wellbeing. in these circumstances, the sudden and stressful situation in addition to prolonged stays at home may imply a radical change in lifestyle behavior such as physical activity (pa), eating habits, alcohol consumption, mental health, quality of sleep, etc. [3] [4] [5] [6] [7] . likewise, there is a general concern about the negative health implications of inactivity and sedentary behavior [8] . the general recommendation for considering an adult to be physically active is to attain at least 150 min of moderate or 75 min of vigorous intensity activity per week or an equivalent combination of both [9] , and sedentary behavior is defined as any waking behavior practiced while lying down, reclining, sitting or standing, involving an energy expenditure ≤ 1.5 metabolic equivalents [10] . while the disease spreads around the world, healthy people are being requested to stay at home for prolonged periods of time and, as a consequence, covid-19 has radically modified the determining factors (individual, interpersonal, environmental, regional or national policies and global) [11] of both types of behavior thus, due to isolation and limitations in engaging in regular and common activities, fulfilling pa recommendations and reducing sedentary behavior during lockdown may pose a significant challenge, especially during the first weeks when the population has limited chances to find alternatives to ensure they remain active even at home. hence, although individuals were encouraged to remain physically active in their homes [12], the unprecedented confinement may give rise to two situations. (1) the active population may decrease their activity and (2) the inactive population may not be likely to increase their daily pa. despite the fact that lockdown has affected several countries, data are scarce about how people have changed their pa and sedentary behavioral patterns because of the specific cases of isolation in each country. therefore, the aim of this study was to analyze self-reported pa and sedentary behavior before and during lockdown caused by covid-19 in a spanish healthy adult population. healthy adults (age 18-64 years, age category defined by who) living in spain were asked to participate in this cross-sectional study. all the subjects were informed about the objective of the study and their free participation in it, being able to leave it whenever they wanted. ethics approval was obtained from the deusto university human ethics advisory group, and informed consent was obtained from participants. sociodemographic data (age, height, weight, gender, whether working and/or studying) and self-reported pa data were collected by questionnaires sent between 23 march and 1 april, just 10 days after the state of emergency was declared in spain. two questionnaires were sent together to be answered consecutively at the same time. the first collected retrospective data about habits during a normal week before lockdown, and the second asked about the following one or two weeks. the questionnaire used was the ipaq short version validated in spanish [13] . the ipaq short version asks about three specific types of activity undertaken during the previous 7 days in the four domains (leisure time, work, household activities and transport); items are structured to provide separate scores for walking, moderately intense and vigorously intense activities. the ipaq version also contains a question about the time spent on sedentary activity. the invitation to participate in the study was issued via social media, e-mail and mobile phone from the physical activity and sports sciences department, university of deusto. moreover, a national sports store (forumsport s.a.) and a biomechanical laboratory (custom4us) also sent the questionnaire to their customers by e-mail. the primary outcome was the change in time and intensity of self-reported pa and the sedentary time prior to the confinement situation and after it. the secondary outcome was the change in the percentage number of participants who fulfilled general pa recommendations according to age, gender, working status and baseline pa levels. a total of 4160 healthy subjects answered the questionnaire. a total of 360 were excluded due to exclusion criteria: not resident in spain (n = 16), age < 18 or ≥65 (n = 110) and extreme scores in vigorous, moderate and walking activities (≥6 h per day, 7 days a week). the exact number of participants excluded was as follows: n = 81 were excluded because the sum of the total active time was >6 h per day (vigorous + moderate + walking). within the pre-covid data, n = 17, n = 31 and n = 62 were excluded because they exercised > 180 min per session at a vigorous level of intensity, >180 at moderate intensity and >21 h (3 h per day, 7 days of week) walking, respectively. finally, within the during-covid data, n = 17, n = 9 and n = 17 were excluded because they exercised >180 min per session at vigorous intensity, >180 at moderate intensity and >21 h (3 h per day, 7 days of week) walking, respectively. a univariate analysis with paired t-tests was used to compare the differences in primary outcomes before and during confinement. furthermore, a chi 2 frequency test was used to assess secondary outcomes, which refer to the change in the percentage number of participants who fulfilled the amount of self-reported pa in the subgroups. a subgroup analysis was performed on different age groups (18-24, 25-34, 35-44, 45-54, 55-64) , gender (m, f), working status (students, active workers, people that study and work, those that reported they did nothing), and self-reported pa, categorized into vigorous activity groups (0-75, 75-150, 150-225, more than 225 min/week) and moderate activity groups (0-150, 150-300, 300-450, >450 min/week). the pa subgroup categories are based on world health organization (who) recommendations. we divided the data into different groups following in accordance with who recommendations for activity of moderate (150 min per week) and vigorous (75 min per week) intensity. within each of the two categories we divided the data into 4 groups as follows: (1) under the amount recommended (less than 150 min of moderate intensity or less than 75 min of vigorous intensity), (2) following recommendations (150 to 300 min of moderate intensity or 75 to 150 min of vigorous activity), (3) twice the amount recommended and (4) three times the amount recommended. this categorization was made to extrapolate the results to the amount of self-reported pa fulfilled by participants in the study, with α level set at 0.05. statistical analysis was performed using the spss data analysis version 23 (spss, inc., chicago, il, usa). table 1 shows the demographic characteristics of 3800 participants who were mostly male, (54%) active workers (78%) and aged 42.7 ± 10.4 years (mean ± sd). (5) data presented as mean ± sd, n (%) using the who stratification, we divided the sample into five bmi groups with n = 77 (2.1%) being the underweight group, n = 2621 (70.0%) normal; n = 897 (24.0%) overweight; n = 144 (3.8%) obese and n = 4 (0.1%) extremely obese (<18.5 kg/m 2 ; 18.5-24.9; 25-29.9; 30-39, 9 and ≥40 groups of bmi score, respectively). during confinement, the amount of time spent on moderate and vigorous activities by all the population decreased by 2.6% (p = 0.102) and 16.8% (p < 0.001), respectively. in addition, walking time was reduced by 58.2% (p < 0.001) whereas sedentary time increased by 23.8% (p < 0.001) ( table 2) . men reported a higher decrease in vigorous activities than women (21% and 9%, respectively) and both reduced walking time to a similar extent (58.5% men, 59.6% women) ( table 2 ). however, sedentary time was reported to have a higher increase in men (35%, p < 0.001) than in women (25.3%, p < 0.001) and accordingly, men significantly reduced moderate activities by 8.2% (p < 0.001) while women increased these activities by 11% (p < 0.05). the student group showed the highest decrease in moderate (16.1% p < 0.05), vigorous (24.3%, p < 0.001) and walking activities (66.9% p < 0.001), whereas unemployed or non-students were proved to be the most sedentary during confinement (47.7%, p < 0.001) ( table 2 ). the adult population (age 55-65 years) decreased the amount of time they spent on vigorous activities the most (22.1%) whereas for moderate activities and walking time it was the youngest subjects (18-24 years) who also evidenced the greatest increase in sedentary time (47.7% p < 0.001). regarding meeting pa recommendations, the number of subjects who failed to complete 75 minutes' activity of vigorous intensity per week before confinement increased by 10.7% (p < 0.001) during lockdown. (table 3 ). in addition, the most active population (>225 min/week of vigorous activity) decreased their activity significantly by 7.7% (p < 0.001). nevertheless, meeting 150 min of moderate activity per week barely changed (1.4%, p value 0.117). in the subgroup analysis, the most active subjects showed the highest decrease in vigorous activity time (30.5%, p < 0.001) ( table 2 ). however, the less active population increased the time they spent on these activities by 34% and this trend is also evidenced in the case of moderate activities. furthermore, walking time declined similarly for all self-reported pa levels, while in terms of sedentary time, the most active group reported the highest increase (40.3%, p < 0.001). self-reported pa decreased significantly during confinement in all the population, in which vigorous and walking activities declined the most and moderate activities barely changed. there were more inactive people who failed to fulfil the 75 min/week of vigorous activities during lockdown and sedentary time also increased considerably. the impact on active and sedentary behavior was particularly high in men, young people, students and the physically very active population. to our knowledge, there are limited previous studies that have analyzed the effect of confinement caused by a pandemic on self-reported pa. thus, it is difficult to assess whether the population we studied has reduced the amount of self-reported pa to a smaller or larger extent. the only available data we found about self-reported pa during confinement comes from activity trackers, where it has been shown that in europe the country with the greatest step count decrease recorded was spain, with 38% less, followed by italy with 25%. this reduction is similar to the falling trend in walking time shown in our study. in this regard, other studies carried out in similar lockdown situations (confinement during seasons with adverse weather conditions-cold winter or heat waves) also reported pa decrease during confinement, whereas sedentary time increased because poor or extreme weather becomes an environmental barrier to going outdoors [14] [15] [16] [17] . sedentary time increased considerably, most likely due to the exchange between common daily active behavior (walking, cycling or transport to work, etc.) and the prolonged stay at home. young people and students spent more time seated during confinement and this may be due to the forced e-learning which encourages sedentary behavior related to excessive time on screen-based activities [18] . likewise, according to the socioecological model [11] , in a comparable framework where social or environmental barriers promote an inactive lifestyle (social isolation, loneliness and, when season changes), more sedentary behavior and less time being spent on light, moderate and vigorous pa have been reported [19] [20] [21] . hence, an involuntary prolonged stay at home may encourage sedentary behavior as well as during confinement caused by covid-19. the most active subjects showed the highest decrease in vigorous activity time and this may be explained by two main reasons: the forced sudden inaccessibility to community resources (e.g., sports facilities, urban trails, parks, green spaces, etc.) and the lack of time to react during the first weeks of confinement to gather fitness resources, in order to continue engaging in regular activities at home. regarding moderate activities, our data showed that it barely changed in all the population and this could be attributed to the fact that some people may have been maintaining the minimum recommended time doing alternative activities at home. in this regard, the less active population increased vigorous and moderate activities during confinement, which could be related to the promotion of such activities by health institutions, fitness centers, the internet and television by posting daily online workout routines. to our knowledge, there are no scientific articles supporting the benefits of promoting pa established during confinement. some specific examples of such activities are spanish national television (morning workouts), the free online classes offered by several institutions and fitness centers (using online platforms such as zoom or google meet) and the recommendations made by health associations. our results showed that there are people who found new ways of being more active during this lockdown, which could become best practices in the future, should a pandemic of similar characteristics hit again. active behavior changed according to gender. both genders reduced walking time to a similar extent, although men reported a higher decrease in vigorous activities that may be related to the greater pa prevalence reported in women over the years. [22] [23] [24] [25] . in terms of sedentary behavior, sitting time increased more highly in men who also significantly reduced moderate activities, while women increased these activities. this could be attributed to the gender gap by historically demonstrated female inequality in household and child care tasks, in which men have shown a low level of involvement in spain [26] [27] [28] . regarding meeting pa recommendations, the global age-standardized prevalence among the inactive population was 27.5% in 2016 [23] . according to the eurobarometer (eurobarometer, 2014), 33.6% of the spanish adult population did not attain minimum levels of pa, and 36% spent most of the day sitting down (national health surveys in spain). in our population, our inactive population before confinement is lower (25.3% corresponding to 75 min/week vigorous pa) than that of the eurobarometer. that may be explained by the fact that the population recruited for the study was particularly more active as shown in the data for people undertaking >225 min/week of vigorous activities, and this could be attributed to the fact that the questionnaire was shared by institutions linked to sport, exercise and biomechanics. therefore, it is to be expected that we recruited a population that is commonly more active than the general population. a limitation of the current study is that we selected the ipaq short version instead of the ipaq-long one because of concerns that the length of the questionnaire would result in significant participant burden. in addition, although the questionnaire collects data about the last seven days, in our study we requested information beyond a week, which may be justified due to the unprecedented situation and the lack of time available to manage more appropriate study design and methods. in order to obtain as many participants as possible, sharing the questionnaire was sent to customers involved in sports and biomechanical issues in addition to being shared on social networks. therefore, a sampling selection bias may have occurred in the population analyzed due to their natural active habits. another limitation could be the cross-sectional design of the study since directionality of the associations cannot be established. finally, the way in which the data were collected in this study can be in itself considered a limitation, since participants reported data in a subjective way when answering self-rated questionnaires. on the other hand, one of the strong points of the study is that the questionnaire was sent just when the population started confinement (during the first two weeks), and so it is likely participants had their common activities in mind before confinement in a fresh and realistic way. to our knowledge, this is the first study carried out on a confined large sample size, which may be useful in designing different strategies in order for the confined population to reduce sedentarism and increase pa. in conclusion, healthy adults reduced daily self-reported pa and increased sedentary time during covid-19 confinement in spain. the impact was particularly high in men, young people, students and the very active population. strategies should thus be employed to increase pa and decrease sedentary behavior. in this study, we tried to ascertain the influence of confinement on the lifestyle of the population. this study may serve to show the effect of an extraordinary measure, such as confinement, on this lifestyle, as well as a greater awareness of the effect of confinement. moreover, the results may help design and target interventions aimed at increasing physical activity and reducing unhealthy levels of sedentary time associated with pandemic mitigation efforts. who director media briefing on covid-19. available online alcohol use and misuse during the covid-19 pandemic: a potential public health crisis? lancet public health 2020, 5, e259 a prospective study of holiday weight gain who mental health. mental health and psychosocial considerations during the covid-19 outbreak dealing with sleep problems during home confinement due to the covid-19 outbreak: practical recommendations from a task force of the european cbt-i academy physical exercise as therapy to fight against themental and physical consequences of covid-19 quarantine: special focus in older people a tale of two pandemics: how will covid-19 and global trends in physical inactivity and sedentary behavior affect one another? on behalf of sbrn terminology consensus project participants. sedentary behavior research network (sbrn)-terminology consensus project process and outcome correlates of physical activity: why are some people physically active and others not? validation of the international physical activity questionnaire-short among blacks the effect of season and weather on physical activity: a systematic review. public health physical activity levels of community-dwelling older adults are influenced by winter weather variables influence of seasonal variations on physical activity in older people living in mountainous agricultural areas comparison of summer and winter objectively measured physical activity and sedentary behavior in older adults: age, gene/environment susceptibility reykjavik study covid-19): the need to maintain regular physical activity while taking precautions associations between social isolation, loneliness, and objective physical activity in older men and women social isolation, loneliness, and health behaviors at older ages: longitudinal cohort study loneliness predicts reduced physical activity: cross-sectional & longitudinal analyses the active living gender's gap challenge: 2013-2017 eurobarometers physical inactivity data show constant higher prevalence in women with no progress towards global reduction goals worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1.9 million participants worldwide variability in physical inactivity a 51-country survey shifting the physical inactivity curve worldwide by closing the gender gap the gender revolution: a framework for understanding changing family and demographic behavior parentalidad y división del trabajo doméstico en españa el impacto de cuidar en la salud y la calidad de vida de las mujeres the authors gratefully acknowledge those who participated in this study and forumsport and custom4us for helping to disseminate the questionnaire. the authors declare no conflict of interest. key: cord-303646-uxewsyli authors: janas, roman m.; socha, jerzy; warnawin, krzysztof; rujner, jolanta title: further studies on aminopeptidase-m in blood in children with cholestatic liver diseases and viral hepatitis date: 1999 journal: dig dis sci doi: 10.1023/a:1026626822298 sha: doc_id: 303646 cord_uid: uxewsyli aim of this study was to determine and furthercharacterize the serum aminopeptidase-m in children withliver diseases. based on our new assay, we have showntwo fractions of the enzyme. activity of the first fraction is expressed in undiluted serumat ph adjusted from 8.5 (ph of storaged serum) to 7.4.activity of the second fraction (cryptic activity)appears in the serum (ph 7.4) as a result of dilution and/or addition of aniline naphthalene sulfonicacid. in children with alagille syndrome, extrahepaticbiliary duct atresia, byler's disease, and acutehepatitis due to hepatitis b virus infection, activities of both fractions are highly elevated ascompared to healthy children or those with chronic viralhepatitis. moreover, serum aminopeptidase-m seems toreflect other aspects of the pathological process than those reflected by the alanine aminotransferaseand gamma-glutamyltranspeptidase. due to increasedactivity and broad substrate specificity, the enzymeseems to be also a cofactor of cholestasis andhepatitis. membrane -bound aminope ptidase -m (ec 3.4.11.2) functions as an ectopeptidase at the cell surface in many tissue s and the re is also a soluble form of this e nzyme in serum and othe r body¯uids (1± 3). serum aminope ptidase -m activity is marke dly increased in patie nts with chole stasis and was shown to be a use ful marke r of he patobiliary dise ase (4 ± 7). the enzyme is thought to originate from the live r (2) . howe ver, its multiple mole cular forms pre sent in se rum may arise from othe r organs and tissue s (6, 8) . in he matology, aminope ptidase -m (cluster of dif-fe rentiation 13) is a well-recognize d marker of mye loid cell le uke mia (9 ± 11) . inte restingly, it has bee n found that aminope ptidase -m on alime ntary or re spiratory tract e pithe lial cells is a receptor for human coronavirus 229e (12) . in a large population of appare ntly healthy humans, the e nzyme activity se ems to e xhibit some variations that are depe nde nt on age , se x, alcohol consumption, smoking, and drug intake (13) . among the substrate s of aminope ptidase -m, including those involve d in growth and differe ntiation re gulation, phagocytosis, and bacte ricidal and tumoricidal activity (3, 4, 9, 14 ± 16) , both methionine (met) and le ucine (le u) enkephalins are rapidly de grade d afte r the ir administration to humans or animals (17± 28) . in circulation, the e ndoge nous enkephalins se em to be prote cted from de gradation through binding to carrier prote ins (19) . howeve r, a fre e fraction of the e nke phalins would be susce ptible to the e nzyme. enkephalins appe ar to be implicate d in chole static live r dise ase and may be an important pathoge nic factor in such complications as pruritus or e nce phalopathy. inde e d, plasma e nke phalin concentrations are highly elevate d in adult patie nts with chole stasis of diffe ring aetiologie s (7, 29 ± 32) , and in rats with an e xpe rime ntal mode l of acute chole stasis (33, 34) . accumulating in blood, e nke phalins may cross the blood± brain barrie r and evoke , via the ir incre ase d availability in the central nervous syste m, a syndrome of chronic opiate -receptor stimulation (35, 36) . preliminary experiments have shown that naloxone or nalme fene , opiate -receptor antagonists, ame liorate d or reve rsed pruritus in patie nts with chronic chole static live r disease and, in some patie nts, pre cipitate d a syndrome that rese mble s the withdrawal reaction of opiate addiction (37, 38) . recently, we have shown that in childre n with chole stasis of diffe ring e tiologie s incre ase d se rum met-enkephalin occurs concom itantly with highly ele vate d se rum aminope ptidase -m activity and that both parame ters were appare ntly not affe cted by a short-te rm treatment with ursode oxycholic acid (39, 40) . alternations in the aminope ptidase -m activity as well as the ir re le vance to the situation in chole stasis and viral he patitis are not fully unde rstood yet, and furthe r syste matic studie s see m to be worthwhile . there fore , in this study we attempted to furthe r characterize and compare the serum aminope ptidase -m activity in he althy childre n, childre n with chole static live r dise ase , and childre n with chronic or acute he patitis due to hepatitis b virus (hbv) infe ction. patients. the protocol of this study was approved by the hospital ethics committe e. the following groups of patie nts were included in the study: group 1, e ight children, 8 ± 14 ye ars old (me an 10 years), with alagille syndrome (arteriohe patic dysplasia) , alanine am inotransfe rase ( alat): blood sam p ling. v enous blood was sampled without anticoagulants for the diagnostic examinations; it was possible to use part of e ach sample in this study. blood samples were centrifuged at 3000g for 15 min at 4°c, and the sera ® ltered through a 0.2-m m ® lte r (sartorius-me mbran® lte r, gottingen, ge rmany) to exclude all residual cell debris, and stored at 2 30°c. serum ph was me asured using a ph microelectrode (sigma chemical co., st louis, missouri). assay of am inop eptid ase-m activity. equal aliquots (500 m l) of the sera we re pooled in groups 1± 6, respective ly, and used for characterization of the aminopeptidase-m. the e nzyme activity was also dete rmined in the individual serum samples from patients from groups 1± 6. dilution of the serum was performed using 25 mmol/liter bistris± tris± ace tic acid buffe r with or without 0.15 mol/liter nacl, at ph range 4.5± 9.0. to maintain the serum ph at a desired leve l, the endogenous hco 3 2 was hydrolyzed with a negligible volume of 1 mol/liter hcl (® nal concentration 25± 30 mmol/ liter). resulting co 2 was remove d under low pressure, and ph was adjusted with a small volume of 1 mol/liter nao h, hcl, or bistris± tris± ace tic acid under the control of a ph microelectrode. the incubation mixture consisted of 100 m l of undiluted or diluted serum and 5 m l of [ 1 25 i] incubation was performed at 37°c for 0 min (control) to 15 min, and terminate d by acidi® cation with 100 mmol/l ace tic acid. de gradation of the substrates was quanti® e d by the aluminum silicate binding assay as recently described (41) with slight modi® cations. a homogenous suspension (50 mg/ml) of aluminum silicate powder (lloyd reage nt, pfaltz and bauer, wate rbury, connecticut) was prepared in 1% acetic acid. aliquots of 2 ml were adde d to the tubes at the e nd of each incubation period. afte r vortexing for 1 min, the tubes were centrifuged at 3000g for 10 min. for [ 12 5 i]leu-enkephalin, the supernatants were discarded by aspiration, and the silicate pellets counted for the g -radioactivity. for the [ 3 h]leu-e nkephalin, 1.5-ml aliquots of the supernatants were mixe d with 5 ml aliquots of the scintillation cocktail and counted for the b -radioactivity. intraand interassay coef® cients of variation we re 4.9% and 10.5% for iodinated and 8.9% and 14.5% for tritiated e nkephalins, respective ly. the e nzyme activity was e xpressed as picograms of degrade d substrate per minute per milliliter whole serum. intact [ 12 5 i]-or [ 3 h]leu-enkephalin was almost complete ly adsorbed by the aluminum silicate (93 6 3% , me an 6 sem, n . 30). reve rse-phase high-performance liquid chromatography showed that silicate pellet-bound radioactivity re pre se nte d the intac t labe le d pe ptide , whereas 85± 90% of the radioactivity appearing in the supernatants was due to [ 1 25 i]-or [ 3 h]tyrosine. unidenti® e d, two to three amino acid fragme nts constituted about 10 ± 15% of the radioactivity and did not react with the speci® c leu-e nkephalin antibody (data not shown). effect of inhibitors an d oth er subs tan ces on am inop eptidase-m. degradation of the labeled leu-enkephalin by serum aminopeptidase-m was quanti® e d by dete rmining the percentage of intact label in the presence of increasing concentrations of speci® e d substances. the exte nt of the label degradation in the control probes, no substance added (35± 40% degradation afte r a speci® e d incubation period) was take n as 100% relative activity. before the assay, the inhibitors to be teste d were preincubated with the serum at ; 20°c for 15 min. the inhibitory constants (k i ) and michaelis constant (k m ) towards unlabeled leu-e nkephalin were determined as previously described (39) . the following substances used in the present study we re purchased from sigma: 1,10-phe nanthroline, bestatin, puromycin, leu-e nkephalin, me t-e nkephalin, bovine serum albumin, 8-aniline naphthalene sulfonic (ans) acid, taurocholic acid, ursodeoxycholic acid, and cholic acid. other chemicals we re of analytical grade. statis tical an alysis. v alues are e xpressed as means 6 se m unless otherwise speci® ed. the mann-whitne y u test was used to dete rmine the signi® cance of differences betwe en means; p , 0.05 was considered signi® cant. during storage , serum ph rise s to 8.5. the e ffect of ph on aminope ptidase -m activity in undilute d se rum pools from groups 1± 6 is shown in figure 1 . the ph curve s were symme tric and dynamic with an optimum at about 6.5± 7.3 for both iodinate d and tritiate d le ue nkephalin. the same data were obtaine d in the e xpe rime nts with dilute d se ra. the increase in serum aminope ptidase -m activity as a result of dilution with 25 mmol/lite r buffe r, ph 7.4, is shown in figure 2a ,b. as shown in figure 2a , the e nzyme activity increased from 45 6 5 (undilute d se rum, ph 7.4) up to maxim al value s of 880 6 90 pg/min/ml (80-fold dilute d serum; value s are means 6 sem) . there were no statistically signi® cant diffe re nce s in the aminope ptidase -m activity be twe e n he althy childre n and those with chronic active he patitis due to hbv infe ction (p . 0.05) . as shown in figure 2b , the e nzyme activity in the undilute d se ra, ph 7.4, from childre n with alagille syndrome , extrahe patic biliary duct atre sia, byler' s dise ase , and acute he patitis due to hbv infe ction was: 411 6 55, 480 6 39, 198 6 25, and 300 6 69 pg/min/ml, re spe ctive ly. in the sample s dilute d 50-to 80-fold, the activity re ache d maximal value s of 6100 6 800, 6900 6 950, 2150 6 280, and 3880 6 410 pg/m in/ml, re spe ctive ly. negligible dilution, up to 1.5-fold, was without effe ct (figure 2a,b) . the same data were obtaine d in the e xpe rime nts whe re buffe re d saline , ph 7.4, se rved as a se rum dilue nt (data not shown) . the effect of the incre asing concentrations of ans acid on aminope ptidase -m activity is shown in figure 3 . in the undilute d and 5-and 30-fold dilute d sera, the e nzyme activity incre ase d about twice in the prese nce of 5, 1 and 0.1 mmol/lite r ans acid, respe ctively. for any dilution, an optim al conce ntration (c) of the ans acid may be estimate d from the following e mpirical formula: 5/a 5 c (in millimole s pe r liter), whe re a is the -fold dilution of the serum. highe r ans acid conce ntrations were inhibitory, but the e nzyme activity did not decrease below its basal le vel (no ans acid adde d). inhibition and substrate spec-i® city data of serum aminope ptidase -m in the se rum pools in groups 1± 6 are shown in table 1 . in both undilute d and dilute d se ra, puromycin, be statin, and amastatin inhibite d the e nzyme with k i value s of about 70 m mol/lite r, 1.8 m mol/lite r, and 70 nmol/lite r, re spective ly. in the prese nce of ans acid, the enzyme se nsitivity to the inhibitors was change d to a certain de gre e; howe ver, pote ncy and se le ctivity range s of the inhibitors re maine d unchange d. the k m value , de te rmined with leu-e nke phalin as substrate , was 359 6 62 m mol/lite r in both undilute d and dilute d se ra from groups 1± 6 ( table 1) . aminope ptidase -m activity in the individual sera from groups 1± 6 was evaluate d unde r diffe re nt assay conditions, and the re sults are shown in table 2 . in the undilute d sample s with ph 8.5, the e nzyme activity was statistically signi® cantly unde restimate d (p , 0.005) as compare d to the same sample s with ph adjuste d to the physiological le vel. maximal enzyme activity was observe d in the samples that were dilute d 80-fold. the se rum aminope ptidase -m activity was statistically signi® cantly highe r in childre n with cholestasis and acute he patitis as compare d to he althy childre n or those with chronic active hepatitis (p , 0.005) . we atte mpte d to de te rmine and characte rize the e xpre ssion and prope rtie s of se rum aminope ptidase -m activity in childre n with live r diseases and in he althy childre n. we have shown the pre sence of two fractions of the enzyme . activity of the ® rst fraction (basic activity) is e xpre ssed in the undilute d or ne gligibly dilute d se rum at ph 7.4. activity of the se cond fraction (cryptic activity) appe ars in the serum as a re sult of dilution and/or addition of ans acid. in childre n with chole stasis and in childre n with acute he patitis due to hbv infection, both fractions of the e nzyme are highly elevate d as compare d to he althy childre n or those with chronic active he patitis due to hbv infection. since enkephalins are among the well-characte rize d, natural aminope ptidase -m substrate s (2, 3, 17, 19 ± 28) , in our assay we use d radiolabe le d le ue nkephalin at a concentration close to the peptide leve l in circulation. [ 3 h]le u-e nkephalin is biologically indistinguishable from the native pe ptide whe reas substitution of the iodine see mingly in¯ue nced the substrate ± e nzyme inte raction, re sulting in a slightly de crease d rate of hydrolysis ( figure 1 ). the enzyme ph optimum was narrow, about 6.5± 7.3, and the activity dramatically decreased outside that range . after one free ze± thaw cycle , the ph of se rum increases to 8.5 due to ne ar comple te co 2 evaporation. to avoid a se rious unde re stimation of the enzyme activity (20 ± 24, 26, 39, 40) , se rum ph must be carefully adjuste d to 7.4 or, alte rnative ly, to the enzyme ph optim um. maintaining the serum ph may be achie ve d by dilution of se rum with an appropriate buffe r. howe ver, as we have shown, a dilution is anothe r factor affe cting the serum aminope ptidase -m activity. whe the r ph plays a role in in vivo re gulation of the e nzyme activity re mains to be determined. aminope ptidase -m activity dynamically increased as a re sult of dilution of the serum with simple buffer or buffe red saline . the plate au of the activity was found in the sample s dilute d 50-to 80-fold, where as a negligible dilution, up to 1.5-fold, was without e ffe ct. in he althy childre n and childre n with chronic active he patitis due to hbv infe ction, enzyme activity incre ase d from 70 (undilute d serum) to 900 pg/min/m l (80-fold dilute d serum). in childre n with byler' s disease, the re spective value s were 240 and 2000 pg/min/ml. the highe st incre ase s were found in childre n with alagille syndrome (from 360 to 6300 pg/min/m l), e xtrahe patic biliary duct atresia (from 430 to 6600 pg/min/ml) , and those with acute he patitis due to hbv infection (from 300 to 4000 pg/min/ml) . in many re ports (6, 7, 11, 13, 19, 23, 27, 33) , including ours (39, 40) , serum dilution was not take n into account as a factor that may affect aminope ptidase -m activity. an increase of e nzyme activity as a result of dilution sugge sts that a large portion of the enzyme molecule s is not hydrolytically active and is prese nt in the se rum as a cryptic fraction. this may be due to prese nce of the enzyme natural inhibitor( s) that dissociate as a result of dilution. if this assumption is true , the n an increase of the se rum aminope ptidase -m in chole stasis and acute he patitis is not due to a de® cie ncy of such an inhibitor since both fractions of the enzyme are highly e levate d. activation of the e nzyme may occur in vivo. re cently, martine z and coworke rs ( 20, 26) have shown that serum aminope ptidase -m activity in rats is capable of changing rapidly in re sponse to environmental e xpe rie nce . howeve r, the mechanism of e nzyme activation as a re sult of se rum dilution re mains to be de te rmine d. addition of ans acid, capable of disrupting weak bonds, incre ase d serum aminope ptidase -m activity in a dose -de pe nde nt manne r ( figure 3 ). howe ver, the mechanisms of incre asing enzyme activity by ans acid and by dilution se em to be diffe rent, and both factors appe ar to act inde pe nde ntly on the e nzyme structure , on re gulatory factors, or both. o ur inhibition and speci® city data have shown substantially the same characte ristics of the e nzyme both in the undilute d and dilute d sera de te rmined with or without the pre sence of ans acid. o ur data sugge st that a re liable aminope ptidase -m assay may be performed using a picomolar conce ntration of the e nke phalin labe le d with iodine or tritium, adde d at a ne gligible volum e to an aliquot of the undilute d se rum with ph adjuste d to the physiological leve l. maximal e nzyme activity may be de te rmine d using 50-to 80-fold-dilu te d se rum. hemolysis must be avoide d since e rythrocyte s contain an abundance of e nke phalin-de grading activity (40) . use of e dta plasma, phosphate , citrate , or barbital buffers marke dly decrease s the e nzyme activity. for the monitoring of aminope ptidase -m activity, a varie ty of substrate s (6 ± 9, 11, 13, 18 ± 26, 28, 33, 42) and technique s may be applie d (7± 11, 20 ± 22, 24, 27, 42) ; howe ver, we have shown he re that a se nsitive , fast, and inexpe nsive alum inum silic ate binding assay is an e xce lle nt method for detection of degradation of 3 h-or 125 ilabe le d enkephalins. chole stasis is associate d with an accumulation of e nkephalins and othe r opiate peptide s in blood that may contribute to pathoge nesis of pruritus or encephalopathy (7, 29 ± 39) . whe the r the opioid syste m is alte re d in acute viral he patitis remains to be de te rmined. although the origin of e nkephalins in cholestasis is unknown (35) , it see ms that an impairm ent of the he patic degradation of these pe ptide s doe s not occur (40) . the refore, an increase of serum aminope ptidase -m in chole stasis may be speculate d to be a home ostatic atte mpt to preve nt unlim ited accumulation of opiate pe ptide s in circulation. howe ver, due to increase d activity, the e nzyme see ms to cause substantial change s in the turnove r of othe r, biologically active peptide s in the blood (43) . there fore , we suggest that the e nzyme is not only a marker but also a cofactor of the disease. the source of se rum aminope ptidase -m was not prove n, but the e nzyme is thought to originate from the live r (2), where it is a he patocyte -membrane -bound metallope ptidase virtually abse nt in the he patocyte cytosol. the e nzyme may re¯ect othe r pathways or aspe cts of the pathological proce ss than those re¯ected by se rum alat or g gtp. inde ed, our patie nts with byle r's disease (se e mate rials and me thods) had a normal le vel of the se rum g gtp, moderate ly increased alat, and high le vels of aminope ptidase -m. in contrast, childre n with active chronic he patitis had e levate d leve ls of g gtp and alat but normal aminope ptidase -m activity. among our six patie nts with acute he patitis due to hbv infe ction (alat . 600 units/lite r), two patie nts had mode rately elevate d g gtp and highly incre ase d aminope ptidase -m activity whe reas four othe r patie nts e xhibite d high incre ase of both parame ters. aminope ptidase -m in the serum e xhibits a high amplitude of change s both in chole stasis and acute viral he patitis. howeve r, its physiological and pathophysiological role , as well as its re levance to the situation in chole static live r dise ase s and viral he patitis will re quire furthe r studie s. our data se e m to provide ne w, important insights for furthe r studie s on a role of this e nzyme. immunocytoche mical localisation of aminope ptidase-m in rat brain and periphe ry: re lationship of the e nzyme localisation and enkephalin metabolism peptidase inactivation of enkephalins: design of inhibitors and bioche mical, pharmacological and clinical applications peptidases involved in the metabolism of bioactive pe ptides e lektrophoretische variante n der alan in± am inope ptidase in se rum be i he patobilia è re n erkrankunge n a radioimmunoassay for the me asure ment of aminopeptidase (microsomal) in human se rum clinical signi® cance of a new isoform of se rum alanine aminope ptidase; re lationship with live r disease and alcohol consumption the he patobiliary disease marker se rum alanine aminopeptidase predominantly comprises an isoform of the hae matological mye loid differentiation antige n and leukae mia marker cd-13/gp150 be hal fj: multiple mole cular forms of human alanine aminopeptidase: immunological properties metalloproteaze activity of cd13/ aminope ptidase-n on the surface of human mye loid cells human myeloid plasma membrane glycoprote in cd-13 (gp150) is identical to aminopeptidase-n gp 150; aminopeptidase -n): pre dominant functional activity in blood ce lls is localised to plasma and is not cell-surface associate d holme s kv : human aminope ptidase-n is a receptor for human coronavirus 229e alanine aminope ptidase in se rum: biological variations and refere nce limits mcde rmott jr: human brain leucyl aminope ptidase: isolation, characte risation and speci® city against some ne urope ptides possible action of human placental aminope ptidase-n in feto-placental unit guste rson ba: ce ll-surface pe ptidases as modulators of growth and diffe rentiation breakdown of small enkephalin deriviates and adrenal pe ptide e by human plasma characte risation of three aminope ptidases puri® ed from mate rnal serum me chanism protecting plasma peptides from e nzyme hydrolysis: a comparative study enke phalin hydrolysis in plasma is highly correlate d with escape pe rformance in the rat ]e nke phalin in rat plasma se nsitive method for me asuring hydrolysis of enkephalins in plasma, using high-performance liquid chromatography with e lectrochemical de tection wards pe: n-terminal degradation of low mole cular we igh opioid peptides in human ce rebrospinal¯uid furthe r characte risation of the in vitro hydrolysis of [le u]-and [me t]enkephalin in rat plasma: hplc-e cd me asurements of substrate and me tabolite conce ntrations uptake and me tabolism of [ 3 h]-le u-enke phalin following either its intraperitoneal or subcutaneous administration to mice e xperience -dependent regulation of le u-enkephalin hydrolysis in rat plasma shun-cun c, berrye r p: a radioche mical assay for aminopeptidase n mentle in r: enkephalin me tabolism by microglia aminopeptidase-n (cd13) opioid pe ptides and primary biliary cirrhosis is ascite s caused by impaired he patic inactivation of blood borne endogenous opioid peptides? methionine enkephalin is incre ased in plasma in acute live r disease and is prese nt in bile and urine plasma leucine enkephalin is increase d in liver diseases endogenous opioids accumulate in plasma in rat model of acute cholestasis. gastroe nterology 103:630 ± brain and plasma leve ls of opioid peptides are altere d in rats with thioace tamide-induced fulminant hepatic failure: implications for the treatme nt of he patic ence phalopathy with opioid antagonists the pruritus of chole stasis: from bile acids to opiate antagonists the pruritus of chole stasis: potential pathogenic and therape utic implications of opioids a controlled trial of naloxone infusions for the pruritus of chronic cholestasis effects of naloxone infusions in patie nts with the pruritus of chole stasis methionine enkephalin concentration and e nke phalin-degrading activity are e levate d in blood in children with cholestasis me thionine e nke phalin and aminopeptidase-m activity in blood in children with cholestasis before and afte r treatme nt with ursodeoxycholic acid an aluminium silicate binding assay for quantitation of de gradation of chole cystokinin octapeptide and other short pe ptides substance p and bradykinin are natural inhibitors of cd13/aminopeptidase-n is the e nzyme a marke r or co-factor of the disease? we thank dr. h. falk, falk foundation e .v. freiburg, germany, for a trave l grant funded to r.m.j., as a result of which we were able to present part of the present data at the x international congress of liver diseases, o ctober 19 ± 21, 1995, basel, switzerland. key: cord-271068-rwx171oj authors: mayer, alejandro m.s.; rodríguez, abimael d.; berlinck, roberto g.s.; fusetani, nobuhiro title: marine pharmacology in 2007–8: marine compounds with antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiprotozoal, antituberculosis, and antiviral activities; affecting the immune and nervous system, and other miscellaneous mechanisms of action date: 2010-09-03 journal: comp biochem physiol c toxicol pharmacol doi: 10.1016/j.cbpc.2010.08.008 sha: doc_id: 271068 cord_uid: rwx171oj the peer-reviewed marine pharmacology literature in 2007–8 is covered in this review, which follows a similar format to the previous 1998–2006 reviews of this series. the preclinical pharmacology of structurally characterized marine compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. antibacterial, anticoagulant, antifungal, antimalarial, antiprotozoal, antituberculosis and antiviral activities were reported for 74 marine natural products. additionally, 59 marine compounds were reported to affect the cardiovascular, immune and nervous systems as well as to possess anti-inflammatory effects. finally, 65 marine metabolites were shown to bind to a variety of receptors and miscellaneous molecular targets, and thus upon further completion of mechanism of action studies, will contribute to several pharmacological classes. marine pharmacology research during 2007–8 remained a global enterprise, with researchers from 26 countries, and the united states, contributing to the preclinical pharmacology of 197 marine compounds which are part of the preclinical marine pharmaceuticals pipeline. sustained preclinical research with marine natural products demonstrating novel pharmacological activities, will probably result in the expansion of the current marine pharmaceutical clinical pipeline, which currently consists of 13 marine natural products, analogs or derivatives targeting a limited number of disease categories. the current article presents the preclinical pharmacology of marine natural products during 2007-8 maintaining the format used in the previous reviews (mayer and lehmann, 2000; mayer and hamann, 2002 , 2005 mayer et al., 2007 mayer et al., , 2009 . the preclinical pharmacology of antitumor and cytotoxic marine compounds has been reported in separate reviews (mayer, 1999; mayer and lehmann, 2001; mayer and gustafson, 2003 , 2006 . we have restricted the current as well as previous reviews to peerreviewed articles reporting the bioactivity or pharmacology of structurally characterized marine compounds. as we have done previously, we have continued to use a modification of schmitz's chemical classification (schmitz et al., 1993) to assign marine natural product structures to six major chemical classes, namely, polyketides, terpenes, peptides, alkaloids, shikimates, and sugars. novel antibacterial, anticoagulant, antifungal, antimalarial, antiprotozoal, antituberculosis and antiviral preclinical pharmacology of marine metabolites are presented in table 1 with the corresponding structures shown in fig. 1 . marine compounds that affect the immune and nervous systems, as well as those with anti-inflammatory effects are grouped in table 2 , with their corresponding structures presented in fig. 2 . finally, marine compounds that have been demonstrated to affect a variety of cellular and molecular targets are exhibited in table 3 , and their structures depicted in fig. 3 . several articles were published during 2007-8 reporting the preclinical pharmacology of extracts or structurally uncharacterized marine compounds, and although these have not been included in the present review, they probably may warrant further investigation: antimicrobial effects of the turkish red alga jania rubens (karabay-yavasoglu et al., 2007) ; antimicrobial activity in portuguese marine cyanobacteria synechocystis sp. and synechococcus sp. extracts towards gram-positive bacteria (martins et al., 2008) ; antibacterial activity against human and fish bacteria from the sub-arctic colonial ascidian synoicum pulmonaria from northern norway (tadesse et al., 2008) ; strong antibiotic-producing potential in actinomycetes from sediments in the trondheim fjord in norway (bredholt et al., 2008) ; antibacterial activity of deep-sea bacteria from sediments of the west pacific ocean ; potent antimicrobial activity in the green alga enteromorpha intestinalis collected in gujarat, india (nair et al., 2007) ; a nonhemolytic antimicrobial lipopeptide derived from the marine bacterium bacillus circulans (das et al., 2008) ; a t-antigen binding lectin with bioactivity against a broad spectrum of gram-positive and gram-negative bacteria from the sea cucumber holothuria scabra (gowda et al., 2008) ; anticoagulant activity of a 100-500 kda polysaccharide isolated from the fermented red seaweed lomentaria catenata which was greater than the clinical anticoagulant heparin (pushpamali et al., 2008) ; antimycobacterial activity in long-chain fatty acids isolated from the red alga polysiphonia virgata (saravanakumar et al., 2008) ; antileishmanial and anti-trichomonal activity in organic extracts of several mexican red and brown algae moo-puc et al., 2008) ; anti-hiv-1 activity of novel sulfated galactans isolated from the chinese red algae grateloupia longifolia and grateloupia filicina ; significant anti-herpes simplex virus activity in a 30 kda polysaccharide isolated from the red alga gracilaria corticata ; immunomodulatory effects of an enzymatic extract from the south korean marine brown alga ecklonia cava on murine splenocytes (ahn et al., 2008) ; immunostimulant properties of a sulfated polysaccharide isolated from the brazilian red alga champia feldmannii ; antioxidant and antimicrobial activity of the indian red and brown seaweed methanolic extracts with high phenolic contents (devi et al., 2008) ; and decreased expression of key regulatory genes involved in cholesterol and fatty acid biosynthetic pathways by the lipid extract of the cyanobacterium nostoc commune var. sphaeroides kützing (rasmussen et al., 2008) . 2. marine compounds with antibacterial, anticoagulant, antifungal, antimalarial, antiprotozoal, antituberculosis, and antiviral activities table 1 presents preclinical pharmacology reported during 2007-8 on the antibacterial, anticoagulant, antifungal, antimalarial, antiprotozoal, antituberculosis, and antiviral pharmacology of the marine natural products (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74) shown in fig. 1 . contributing to the global search for new antimicrobials to combat antibiotic-resistant strains of pathogenic bacteria, marine ecological niches have been described recently as "particularly promising" (fischbach and walsh, 2009) . during 2007-8, 38 studies reported novel antibacterial marine natural products isolated from marine bacteria, fungi, sponges, worms and fish, a larger effort than the ones reported in previous years (mayer et al., 2009) , and previous reviews of this series. only six papers provided detailed mechanism of action studies with marine antimicrobial compounds. kanoh et al. (2008b) reported the discovery of the novel bioactive spirodioxynaphthalene ascochytatin (1) isolated from cultures of a marine-derived fungus ascochyta sp. ngb4, which inhibited b. subtilis growth (mid= 0.3 μg/disk) by targeting the function of the bacterial growth regulatory system tcs (yycg/yycf). kitani et al. (2008) discovered that the 120 kda acidic glycoprotein l-amino acid oxidase termed ssap (2), isolated from the rockfish sebastes schlegelli (kitani et al., 2007) , acted selectively on gram-negative bacteria (minimum inhibitory concentration (mic) = 0.078-0.63 μg/ml). while h 2 o 2 was shown to mediate the antibacterial action of ssap, electron microscopy analysis revealed that ssap induced cell surface damage and morphological changes in several bacterial species. reported that the 21-residue peptide arenicin-1 (3) isolated from the marine polychaete arenicola marina exhibited significant antibacterial activity against p. aeruginosa and staphylococcus aureus (mic = 2 μg/ml). interestingly, arenicin-1 induced release of calcein from pe/pg liposomes, thus suggesting that the bacterial cell membrane is the main molecular target of the peptide. jang et al. (2007c) extended the pharmacology of the alkaloid isoaaptamine (4), isolated from the marine sponge aaaptos aaptos. isoaaptamine inhibited sortase a (ic 50 =3.7 μg/ml), an enzyme involved in s. aureus cell wall protein anchoring and virulence, thus potentially providing a novel lead compound "for further development" of potent antibacterials. lee et al. (2008) isolated seven sesterterpenes (5, 6, 7, 8, 9, 10, 11 ) from a tropical sponge dysidea sp. which demonstrated antibacterial activity against b. subtilis (mic = 1.56-12.5 μg/ml) by inhibiting isocitrate lyase activity, a key enzyme in the glyoxylate cycle which is present in most prokaryotes, lower eukaryotes and plants, but not in vertebrates. kanoh et al. (2008a) described a new sulfoalkylresorcinol (12) isolated (kossuga et al., 2008) (continued on next page) from the marine-derived fungus zygosporium sp. knc52, which showed antimicrobial activity against methicillin-resistant s. aureus. the mechanism of action appeared to involve inhibition (ic 50 =12.5 μg/ ml) of the in vitro polymerization of ftsz, a protein which is a structural homolog of eukaryotic tubulin, and that participates in bacterial cell division. as shown in table 1 , several new marine antibacterials were also reported in 2007-8 ( fig. 1) with mics less than 10 μg/ml against antibiotic-resistant bacterial strains, although no mechanism of action studies were reported: the alkaloids ambiguine isonitriles h and i (13 14) isolated from a marine cyanobacterium fischerella sp. (raveh and carmeli, 2007) ; the polyketides ariakemicins a and b (15, 16) isolated from a marine gliding bacterium rapidithrix sp. (oku et al., 2008) ; ayamycin (17) isolated from a bacterium nocardia sp. alaa 2000 (el-gendy et al., 2008a) ; the alkaloids batzelladines l and m (18, 19) isolated from the caribbean sponge monanchora unguifera (hua et al., 2007) ; a diphenyl ether (20) isolated from the indonesian sponge lamellodysidea herbacea (hanif et al., 2007) ; essramycin (21) obtained from the culture broth of a marine streptomyces sp. isolate merv8102 (el-gendy et al., 2008b) ; a meroditerpene (+)-isojaspic acid (22) isolated from the papua new guinean sponge cacospongia sp. (rubio et al., 2007) ; the bisindole pyrroles lynamicins a-d (23, 24, 25, 26) isolated from a novel marine actinomycete marinispora sp. (mcarthur et al., 2008) ; lipoxazolidinones a and b (27, 28) isolated from a marine actinomycete marinispora sp. (macherla et al., 2007) ; marinopyrrole a (29) isolated from an obligate marine streptomyces strain (hughes et al., 2008) ; a furanosesquiterpene (-)-microcionin-1 (30) isolated from a marine sponge fasciospongia sp. (gaspar et al., 2008) ; a macrolide phomolide b (31) isolated from a fungus phomopsis sp. ; a sargaquinoic acid derivative (32) isolated from the brown alga sargassum sagamianum (horie et al., 2008) , and tauramamide (33), a lipopeptide isolated from the bacterium brevibacillus laterosporus png276 (desjardine et al., 2007) . furthermore during this period, several novel marine metabolites with moderate antimicrobial activity (mic or ic 50 ranging from 10 to 50 μg/ml, or 10 to 50 μm, respectively), were also reported, but their weaker antibacterial activity precluded their inclusion in either table 1 or fig. 1 : acetylmajapolene a (mic = 20 μg/disk) (vairappan et al., 2008) , callophycoic acids a, b, g and h (mic = 16-63.9 μg/ml) (lane et al., 2007) ; corallidictyals a, b, c and d (mic less than 20 μg/ ml) ; (s)-(+)-curcuphenol analogs (ic 50 = 34-44 μm) (gul et al., 2007) ; cyclomarazines a and b (mic = 13-18 μg/ ml) (schultz et al., 2008) ; dehydroxychlorofusarielin b (mic = 62.5 μg/ml) (nguyen et al., 2007) , nodosol (mic = 16 μg/ ml) (kontiza et al., 2008) ; paeciloxanthone (mic = 40 μg/disk) , palmitoleic acid (ic 50 = 10-20 μm) (desbois et al., 2008) ; puupehenone-metabolites (mic = 8-16 μg/ml) ; tripalea clavaria c-secosteroids (mic = 25 μg/disk) (rodriguez brasco et al., 2007) , shishididemniols a and b (mic = 20 μg/disk) (kobayashi et al., 2007b) , and zafrin (mic = 50-125 μg/ml) (uzair et al., 2008) . noteworthy were reports of novel marine antimicrobial peptides: dicentracin, a new component of the moronecidin family isolated from head kidney leukocytes from the sea bass dicentrarchus labrax (salerno et al., 2007) ; hepcidins, three novel antimicrobial peptides isolated from the tilapia oreochromis mossambicus, with mics (50-100 μg/ml) against listeria monocytogenes, s. aureus, and enterococcus faecium (huang et al., 2007) ; scygonadin, a novel anionic antimicrobial peptide from the seminal plasma of the mud crab, scylla serrata , and tunichromes, small dehydrodopaminecontaining peptides found in hemocyte cells of the ascidian ascidia nigra that are capable of crosslinking proteins in vitro (cai et al., 2008) . four articles published during 2007-8, reported anticoagulant marine natural products isolated from algae and clams, a number very similar to that reported in our previous review (mayer et al., 2009) , and other reviews of this marine pharmacology series. jung et al. (2007b) characterized a novel 7.7 kda anticoagulant polypeptide termed tgap with a partial sequence (34) from the muscle protein of the south korean bivalve tegillarca granosa. the anticoagulant polypeptide, which demonstrated low in vitro cytotoxicity to venous endothelial cells, specifically inhibited the blood coagulation factor va, as well as the molecular interaction between factor iia and factor va in a ascochytatin (1 thrombin as well as potentiated antithrombin iii-mediated inhibition of coagulation factor xa. ten studies during 2007-8 reported on the antifungal activity of several novel marine natural products isolated from marine algae, bacteria, sponges and sea cucumbers, a decrease from our last review (mayer et al., 2009) , and previous reviews of this series. as shown in table 1 , only one report extended the molecular pharmacology of novel antifungal marine metabolites. symphyocladia latiuscula bromophenols (192, 193, 194, 195 furthermore, several marine natural products showed significant antifungal activity (i.e. mics that were either less than 10 μg/ml, 10 μm, or 10 μg/disk) (table 1 and fig. 1; 38 , 39, 40, 41, 42, 43, 44) , although no mechanism of action studies were reported in the published articles: callipeltins j and k (38, 39), mic = 1 μm (d' auria et al., 2007) , the triterpene glycoside holothurin b (40), mic = 1.56 μg/ ml (kumar et al., 2007) , the macrolide neopeltolide (41), mic = 0.62 μg/ml , the cyclopeptide pedein a (42), mic= 0.6-1.6 μg/ml (kunze et al., 2008) , and pseudoceratins a and b (43, 44), mic = 6.5-8.0 μg/disk (jang et al., 2007b) . hopefully, future studies on the molecular pharmacology of these marine compounds will elucidate their mechanisms of action. finally, several novel structurally characterized marine molecules isolated from sponges demonstrated mics or ic 50 s greater than 10 μg/ ml or 10 μm, and therefore, because of the reported weaker antifungal activity, they have been excluded from table 1 and fig. 1 : eurysterols a and b (mic = 15.6-62.5 μg/ml) (boonlarppradab and faulkner, 2007) ; nagelamides m and n (mic = 33.3 μg/ml) (kubota et al., 2008) , nortetillapyrone (mic = 31-62 μg/ml) (wattanadilok et al., 2007) , and tydemania expeditionis triterpenoids (ic 50 = 26-55 μm) (jiang et al., 2008) . these marine compounds may yet provide additional pharmacological leads in the ongoing global search for clinically useful antifungal agents. as shown in table 1 an increase from our previous review (mayer et al., 2009) , and previous reviews of this series. as shown in table 1 , nine marine molecules were shown during 2007-8 to possess significant antimalarial activity, although mechanism of action studies were reported for only two compounds. tasdemir et al. (2007) reported that (e)-oroidin (45) and (e)-oroidin tfa salt (46) isolated from the turkish marine sponge agelas oroides potently inhibited cultures of multidrug resistant k1 strain of plasmodium falciparum (ic 50 = 3.9 and 7.9 μg/ml, respectively) with concomitant inhibition of fabi (enoyl-acp reductase), a key enzyme of the type ii fatty acid synthase cascade (ic 50 = 0.3 and 5.0 μg/ml, respectively). further studies revealed that oroidin free base appeared to bind to "the enzyme-substrate complex or enzyme-cofactor complex" by an uncompetitive mechanism, providing further pharmacological characterization of the "first antimalarial marine natural product that targets p. falciparum fabi". additional antimalarial activity was reported for seven marine compounds. two reports were contributed during 2007 by the panama international cooperative biodiversity groups project: mcphail et al. (2007) isolated a novel linear lipopeptide dragomabin (47) from the cyanobacterium lyngbya majuscula with moderate antimalarial activity (ic 50 =6.0 μm), and significant differential toxicity between the malarial parasite and mammalian cells. linington et al. (2007) discovered that the new cyclic hexapeptides venturamides a and b (48, 49) isolated from a panamanian marine cyanobacterium oscillatoria sp., demonstrated significant in vitro antiplasmodial activity against the w2 chloroquinone-resistant strain of the parasite (ic 50 =5.6-8.2 μm), with mild cytotoxicity to mammalian cells, the first "example of the identification of cyanobacterial peptides with selective antimalarial activity". kasettrathat et al. (2008) proved that a new tetronic acid, nodulisporacid a (50), from a marine-derived fungus nodulisporium sp. crif1 isolated from a thai soft coral, was moderately antiplasmodial (ic 50 =1-10 μm) against chloroquine-resistant p. falciparum strain 94. na et al. (2008) identified a new marine streptomyces sp. h668 polyether (51) from hawaii that showed in vitro antimalarial activity (ic 50 =0.1-0.2 μg/ml) against both p. falciparum chloroquine-susceptible (d6) and -resistant (w2) clones, with minimal cytotoxicity towards mammalian cells. clark et al. (2008) found that a novel acylproline derivative, tumonoic acid i (52) from the papua new guinean marine cyanobacterium blennothrix cantharidosmum, showed moderate antimalarial activity against p. falciparum (ic 50 =2 μm). pontius et al. (2008a) isolated a heterocyclicsubstituted xanthone, chaetoxanthone b (53) from cultures of a marinederived fungus chaetomium sp. that showed selective activity towards p. falciparum k1 strain (ic 50 =0.5 μg/ml). four marine compounds were reported to possess antiprotozoal activity. kossuga et al. (2008) re-isolated the previously reported plakortide p (54) from the marine sponge plakortis angulospiculatus. the compound displayed selective effects against both leishmania chagasi (ic 50 = 0.5-1.9 μg/ml) and trypanosoma cruzi (ic 50 = 2.3 μg/ ml), with low concomitant hemolytic and cytotoxic activities towards human macrophages. reportedly, the mechanism of action towards intracellular l. chagasi did not appear to involve nitric oxide. simmons et al. (2008) found that two novel lipopeptides viridamides a and b (55, 56) were nearly "equipotent" in inhibiting both leishmania mexicana (ic 50 = 1.1 μm) and t. cruzi (ic 50 = 1.5 μm). besides the antimalarial activity, pontius et al. (2008a) discovered that chaetoxanthone b (53) had selective effects towards t. cruzi (ic 50 = 1.5 μg/ ml), with minimal cytotoxicity towards rat skeletal l6 myoblasts (ic 50 = 47 μg/ml). ten new marine compounds were reported in the global search for novel antituberculosis agents, a considerable increase from our previous reviews (mayer et al., 2009) , and previous reviews of this series. ospina et al. (2007) isolated a bioactive oxapolycyclic diterpene bipinnapterolide b (57) from the colombian gorgonian coral pseudopterogorgia bipinnata which weakly inhibited growth of m. tuberculosis h 37 rv (66% inhibition at 128 μg/ml). zhang et al. (2008) identified two new dimeric naphtha-γ-pyrones 8′-o-demethylnigerone (58) and 8′-o-demethylisonigerone (59) from the marinederived fungus aspergillus carbonarius which showed weak antimycobacterial activity against m. tuberculosis (h 37 rv, mic = 43 and 21.5 μm, respectively). interestingly, the presence of conjugated c=c-c=o bonds in the pyrane ring appeared to be crucial for antifungal activity. as a result of a continued investigation of the caribbean sea whip pseudopterogorgia elisabethae, wei et al. (2007a) reported that the novel tricarbocyclic norditerpenes caribenols a (60) and b (61) weakly inhibited m. tuberculosis (h 37 rv, mic = 128 and 63 μg/ml, respectively). furthermore, wei et al. (2007b) discovered two novel ring b abeo-sterols parguesterols a (62) and b (63) in the caribbean sponge svenzea zeai, which inhibited m. tuberculosis (h 37 rv, mic = 7.8 and 11.2 μg/ml, respectively). hopefully future information on the selectivity index of these two compounds will provide additional information to support the notion that they might "constitute important lead structures for the development of novel tuberculosis drugs due to their strong activity, specificity, and low toxicity". berrue et al. (2007) noted that several bioactive polyketides, 24-norisospiculoic acid a (64), dinorspiculoic acid a (65), and norspiculoic acid a (66) from the caribbean sponge plakortis zyggompha also inhibited m. tuberculosis (h 37 rv, mic 99 = 50 μg/ml). although all of these studies demonstrate that marine terpenes and polyketides constitute potentially novel antituberculosis leads, they unfortunately did not provide detailed mechanism of action pharmacology at the time of their publication. as shown in table 1 , three reports were published on the antiviral pharmacology of novel marine natural products against severe acute respiratory syndrome (sars) corona virus, herpes simplex, and dengue virus during 2007-8. de lira et al. (2007) discovered that the new esculetin-4-carboxylic acid ethyl ester (67) from the brazilian marine sponge axinella cf. corrugata inhibited the sars 3cl protease (ic 50 =46 μm). this is a potentially significant finding because the 3cl protease is a "high profile target" in sars drug development as it appears to be involved in the release of replicative viral proteins as well as the rna polymerase. talarico et al. (2007) reported that a d,l-galactan hybrid c2s-3 (68) isolated from the brazilian marine alga cryptonemia crenulata showed potent antiviral activity against three clinical strains of dengue virus serotype 2 (ic 50 =0.8-16 μg/ml), together with low cytotoxicity. further mechanistic work determined that c2s-3 appeared to be a "promising denv-2 entry inhibitor". mandal et al. (2008) described a sulfated xylomannan isolated from the indian red seaweed scinaia hatei which inhibited hsv-1 and hsv-2 (ic 50 =0.5-1.4 μg/ml), with low cytotoxicity, probably interfering with the hsv-1 multiplication cycle. interestingly the "very good antiviral activity against the wide spectrum of hsv strains tested" suggested this compound might be a good candidate for further preclinical research. five reports contributed preclinical pharmacology of marine compounds active against the human immunodeficiency virus type-1 (hiv-1), the causative agent of the acquired immunodeficiency disease syndrome (aids), an increase from our previous reviews (mayer et al., 2009) , and previous reviews of this series. artan et al. (2008) reported that the phlorglucinol derivative 6, 6′-bieckol (69) isolated from the brown alga e. cava inhibited hiv-induced syncytia formation (ic 50 = 1.72 μm), viral p24 antigen production (ic 50 = 1.26 μm), and the activity of the hiv reverse transcriptase (ic 50 = 1.07 μm), with "no cytotoxicity" at concentrations that inhibited hiv replication "almost completely". cirne-santos et al. (2008) extended the molecular pharmacology of the diterpene dolabelladienetriol (70) isolated from the marine brown alga dictyota pfaffii. the dolabellane diterpene blocked both synthesis and integration of the hiv-1 provirus by noncompetitively inhibiting the reverse transcriptase enzyme (ki = 7.2 μm). the investigators proposed dolabelladienetriol (70) as a "potential new agent for anti-hiv-1 therapy". plaza et al. (2007) described three new depsipeptides mirabamides a, c and d (71, 72, 73) isolated from the sponge siliquariaspongia mirabilis that potently inhibited both hiv-1 in neutralization (ic 50 = 0.14-0.19 μm) and hiv-1 envelope-mediated cell fusion (ic 50 = 0.14-3.9 μm), suggesting these compounds act at an early stage of hiv-1 cell infection, "presumably through interactions with hiv-1 envelope proteins". lu et al. (2007) added a "novel mechanistic profiling" of the previously reported sulfated polymannuroguluronate (spmg) (74), a polysaccharide with an average molecular weight of 8.0 kda isolated from the brown alga laminaria japonica, that has been reported to be in phase ii clinical trials in china as an anti-aids drug candidate. spmg appeared to eliminate the viral gene product known as transactivator of transcription protein (tat)induced signal transduction as well as angiogenesis in aidsassociated kaposi's sarcoma cells. furthermore, in 2008, hui et al. (2008) demonstrated that spmg appeared to show a neuroprotective effect because it decreased apoptosis caused by tat-stimulated calcium overload in pc12 neuronal cells, thus suggesting spmg might warrant further clinical studies in hiv-associated dementia. table 2 summarizes the preclinical pharmacological research completed during 2007-8 with the marine compounds (75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132) shown in fig. 2. the anti-inflammatory pharmacology of marine compounds reported during 2007-8 showed a considerable increase from our previous review (mayer et al., 2009) , and previous reviews of this series. several marine natural products were shown in preclinical pharmacological studies to target arachidonic metabolism in neutrophils and macrophages. pearce et al. (2007a) reported two new tricyclic alkaloids ascidiathiazone a (75) and b (76) isolated from a new zealand ascidian aplidium species that affected superoxide production by human neutrophils in vitro (ic 50 = 0.44-1.55 μm), as well as murine peritoneal neutrophis ex vivo, with concomitant "low or nonexistent" liver and renal toxicity, thus suggesting that these two compounds might become "potential anti-inflammatory pharmaceutical" leads. chao et al. (2008) identified the new cembranolides crassumolides a and c (77, 78) from the soft coral lobophytum crassum which inhibited expression of inos and cox-2 (apparent ic 50 less than 10 μm). similarly, from the same university, cheng et al. (2008) found that new cembranolides from the soft coral lobophytum duru, durumolides a-c (79, 80, 81) inhibited both the inos and cox-2 proteins in lps-activated raw 264.7 cells in vitro (apparent ic 50 less than 10 μm), suggesting that the α-methylene-γ-lactone moiety of these compounds was necessary for the observed activity. shen et al. (2007) showed that new briarane-type diterpenoids frajunolides b and c (82, 83), isolated from the taiwanese gorgonian junceella fragilis, significantly inhibited superoxide anion and elastase generation from human neutrophils in vitro (apparent ic 50 greater than 10 μg/ml). dang et al. (2008) demonstrated that the previously described fatty acids (84, 85) from the south korean marine red alga gracilaria verrucosa inhibited release by lps-activated murine macrophages of the inflammatory nitric oxide, tumor necrosis factor α and interleukin-6 (apparent ic 50 less than 20 μg/ml), thus revealing that the conjugated enone moiety played a critical role in the antiinflammatory activity observed in vitro. bittencourt et al. (2008) contributed novel preclinical pharmacology on a previously reported 90 amino acid polypeptide (86) isolated from the red alga hypnea cervicornis. the mucin-binding agglutinin, which was extensively characterized with several in vivo models of nociception and inflammation, probably exerted its anti-inflammatory activity (apparent ic 50 = 0.1-1 mg/kg) via interaction of the polypeptide with the lectin carbohydrate-binding site, although the exact mechanism of action remains undetermined. el sayed et al. (2008) demonstrated that manzamine a (87), (−)-8-hydroxymanzamine a (88), and hexahydro-8-hydroxymanzamine a (89) potently inhibited txb 2 generation (ic 50 = 0.25, less than 0.1, and 1.97 μm, respectively) in brain microglia. these findings provide further support to the notion that manzamine alkaloids appear to be "viable anti-inflammatory leads" for the preclinical pharmaceutical development of agents to modulate both activated brain microglia and eicosanoid generation. treschow et al. (2007) investigated four novel ω-3 polyunsaturated fatty acids (90, 91, 92, 93) from the new zealand green-lipped mussel perna canaliculus with an in vitro bioassay that used stimulated human neutrophil 5-lipoxygenase, demonstrating that the putative antiinflammatory potential of these compounds might be related to inhibition of leukotriene and prostaglandin metabolite production. sansom et al. (2007) reported a bis-prenylated quinone (94) from the new zealand brown alga perithalia capillaris which inhibited superoxide anion production in human neutrophils (ic 50 = 2.1 μm) in vitro, with low toxicity. an explanation as to why the authors decided not to investigate the quinone "as an anti-inflammatory lead" remains unclear, although it was strongly cytotoxic towards human leukemia cells (ic 50 = 0.34 μm). sugiura et al. (2007) characterized a novel antiallergic phlorotannin phlorofucofuroeckol b (pff-b) (95) from the edible brown alga eisenia arborea. pff-b, inhibited β-hexosaminidase release from rat basophilic leukemia cells (ic 50 = 7.8 μm) in vitro, thus showing higher potency than tranilast (rizaben®) (ic 50 = 46.6 μm), a pharmaceutical agent used for treatment of allergic disorders such as asthma, allergic rhinitis and atopic dermatitis in japan and south korea. kossuga et al. (2008) demonstrated that the polyketide plakortide p (54) isolated from the brazilian sponge p. angulospiculatus, potently inhibited thromboxane b 2 release (ic 50 = 0.93 μm) from activated rat brain microglia, thus extending the preclinical pharmacology of this compound, which besides being antiparasitic as discussed earlier in this review, also appears to be a potentially "novel antineuroinflammatory agent". pearce et al. (2007b) examined a halogenated furanone rubrolide o (96) isolated from a new zealand ascidian synoicum n. sp., which inhibited superoxide anion production in human neutrophils (ic 50 = 35 μm) in vitro with low toxicity. although rubrolides have been reported to be cytotoxic and antibacterial, the authors proposed that the anti-inflammatory activity for these tunicate metabolites though moderate was "unprecedented". khan et al. (2007) identified a ω-3 polyunsaturated fatty acid stearidonic acid (97) from the south korean brown seaweed undaria pinnatifida, which was shown to be very active against pmainduced mouse ear inflammation symptoms, edema, erythema and blood flows (ic 50 = 160, 314 and 235 μg/per ear, respectively). the in vivo data compared well with indomethacin which was used as a positive control (ic 50 = 90, 172, 179 μg/per ear, respectively), and thus supported claims that this "seaweed can be used as a remedy for inflammation-related symptoms". kobayashi et al. (2007a) discovered a novel dimeric oroidin derivative carteramine a (98) in the marine sponge stylissa carteri, and showed that it inhibited neutrophil chemotaxis (ic 50 = 5 μm). the authors suggested that because carteramine a has no structural resemblance to known compounds that inhibit neutrophil chemotaxis, their finding provides a "novel platform to develop a new class of anti-inflammatory agents". taori et al. (2007) identified three new analogues of dolastatin 13, lyngbyastatins 5-7 (99, 100, 101), isolated from marine cyanobacteria lyngbya spp. from south florida. although the three compounds selectively and potently inhibited porcine pancreatic elastase (ic 50 = 3-10 nm), suggesting a potential therapeutic use in pathophysiological conditions where elastase overactivity is involved, no mechanism of action studies were reported at the time. oh et al. (2008) purified a novel polyketide salinipyrone a (102) from the marine actinomycete salinispora pacifica, which moderately inhibited interleukin-5 (ic 50 = 10 μg/ml) in a mouse splenocyte model of allergic inflammation, with low cell cytotoxicity. the pharmacology of the marine compounds reporting activity on the immune system during 2007-8 showed a considerable increase from our previous review (mayer et al., 2009) , and previous reviews of this series. kawauchi et al. (2007) investigated the red pigment cycloprodigiosin hydrochloride (103) isolated from the marine bacterium pseudoalteromonas denitrificans. interestingly, the compound suppressed activator protein 1 (ap-1) (apparent ic 50 = 1 μm), and downstream gene expression of interleukin 8, a chemokine involved in the innate immune system. courtois et al. (2008) assessed the effect of the known compound floridoside (104), isolated from the french red alga mastocarpus stellatus on the complement system. floridoside was observed to potently activate the classical complement pathway (apparent ic 50 = 5.9-9.3 μg/ml) by recruiting immunoglobulin m (igm), suggesting that the compound might be an "important step in the development of a potent new anticomplementary agent" useful in therapy aimed at addressing complement depletion. greve et al. (2007) reported that the novel iso-iantheran a and 8-carboxy-iso-iantheran a (105, 106) purified from the australian marine sponge ianthella quadrangulata demonstrated agonist activity at p2y 11 receptors (ic 50 = 1.29 and 0.48 μm, respectively). this finding represents an interesting contribution to ionotropic purine receptor p2y 11 pharmacology, because these receptors have been shown to affect the maturation and differentiation of dendritic cells. huh et al. (2007) extended the pharmacology of prodigiosin (107) isolated from the marine bacterium hahella chejuencis collected in south korea. prodigiosin inhibited inos mrna expression and no production (apparent ic 50 = 0.1 μg/ml) by a mechanism that involved inhibition of nf-κb and p38 mapk and jnk phosphorylation. he et al. (2007) characterized the pharmacology of a water soluble polysaccharide (108) isolated from the mollusc arca subcrenata lischke, a popular chinese seafood, and named it aslp. aslp stimulated mouse spleen lymphocyte proliferation in a concentration-dependent manner (apparent ic 50 less than 100 μg/ml), and with the "branches of aslp" being required for the immunomodulatory bioactivity. aminin et al. (2008) described the immunostimulant activity of frondoside a (109), a triterpene glycoside isolated from the sea cucumber cucumaria frondosa. the glycoside was shown to stimulate lysosomal activity and phagocytosis in mouse macrophages, as well as reactive oxygen species formation. oda et al. (2007) provided novel information on the molecular mechanisms affected by smenospongidine, smenospongiarine and smenospongine (110, 111, 112) , sesquiterpene quinones previously isolated from a palauan marine sponge hippospongia sp. the observation that at 10 μg/ml, these compounds promoted interleukin-8 release, a member of the c-x-c chemokine superfamily which is involved in tumor progression and metastasis, suggested that "the functional group at c-18" might play a yet undetermined role in the observed results. yamada et al. (2007) isolated the novel macrosphelide m (113) and peribysin j (114) from periconia byssoides, a fungal strain discovered from the sea hare aplysia kurodai. significantly, both fungal metabolites inhibited the adhesion of human promyelocytic leukemia hl-60 cells to human umbilical vein endothelial cells (ic 50 = 33.2 and 11.8 μm, respectively) more potently than herbimycin a (ic 50 = 38 μm). the latter compound, a benzochinoid ansamycin antibiotic isolated from streptomyces sp. was used as a positive control in these studies. lu et al. (2008) contributed a novel cembranolide querciformolide c (115) from the soft coral sinularia querciformis, which significantly inhibited the activation of the inos and cox-2 enzymes (apparent ic 50 less than 10 μm) in lps-activated murine macrophages in vitro. ponomarenko et al. (2007) discovered that new diterpenoids (116, 117) isolated from a northern cook islands marine sponge spongia (heterofibria) sp. moderately activated murine splenocytes lysosomes (apparent ic 50 greater than 100 μg/ml). oh et al. (2007) characterized a novel cyclic peptide thalassospiramide b (118) isolated from a marine bacterium thalassospira sp., which showed immunosuppressive activity in an interleukin-5 (il-5) inhibition assay (ic 50 = 5 μm); an interesting finding because il-5 is expressed both in eosinophils and mast cells in asthmatic patients. pharmacological studies with marine compounds affecting the nervous system involved three areas of neuropharmacology: the stimulation of neurogenesis, the targeting of receptors, and other miscellaneous activities on the nervous system. marine natural products reported to be neuritogenic, might be used to treat damaged neuronal cells, and potentially neurodegenerative diseases. as shown in table 2 , compounds (119, 120, 121, 122, 123, 124, 125, 126) isolated from sea stars and a brown alga were observed to enhance the neuritogenic properties of nerve growth factor (ngf), a compound that has a critical role in differentiation, survival, and neuronal regeneration. kicha et al. (2007b) contributed two new steroid glycosides, linckosides l1 (119) and l2 (120) isolated from the vietnamese blue sea star linckia laevigata. all three glycosides (apparent ic 50 = 0.3 μm) showed synergistic effects on ngf-induced (2 ng/ml) neurite outgrowth of murine neuroblastoma c-1300 cells. han et al. (2007) contributed the novel steroid glycosides linckosides m-q (121, 122, 123, 124, 125) from the japanese sea star l. laevigata. linckoside p (124) induced neurite outgrowth in 55% of rat pheochromocytoma pc12 cells at 10 μm in the presence of nerve growth factor (ngf), while linckosides m-o appeared less active (21-32%), suggesting the importance of "the xylose on a side chain". ina et al. (2007) characterized pheophytin a (126) purified from the japanese brown alga sargassum fulvellum as a novel neurodifferentiation compound. pheophytin a at 3.9 μg/ml was observed to synergize with ngf (50 ng/ml) in promoting neurite outgrowth in rat pheochromocytoma pc12 cells by a mechanism that appeared to involve activation of mitogen-activated protein kinase signaling. as shown in table 2 , during 2007-8, three marine compounds (127, 128, 129) were reported to target receptors in the nervous system. peng et al. (2008) reported on the preclinical pharmacology of the α4/7conotoxin lp1.1 (127) originally isolated from the marine cone snail conus leopardus. the conotoxin induced seizure and paralysis in goldfish, and selectively yet reversibly inhibited acetylcholine-evoked currents in xenopus oocytes expressing rat α6α3β2 and α3β2 nicotinic receptors (apparent ic 50 less than 10 μm). aiello et al. (2007) characterized two novel bromopyrrole alkaloids damipipecolin (128) and damituricin (129) isolated from the mediterranean sponge axinella damicornis that were observed to modulate serotonin receptor activity in vitro. although damipipecolin inhibited ca 2+ entry in neurons (apparent ic 50 =1 μg/ml), the serotonin receptor subtype involved in the mechanism of action remains undetermined. finally, as shown in table 2 , during 2007-8, additional marine compounds (74 and 130, 131, 132) were reported to have miscellaneous effects on components of the nervous system. contributing to the ongoing search for acetylcholinesterase inhibitors useful in the treatment of alzheimer's disease, langjae et al. (2007) reported a new stigmastane-type steroidal alkaloid 4-acetoxy-plakinamine b (130), isolated from a thai marine sponge corticium sp. that significantly inhibited acetylcholinesterase (ic 50 = 3.75 μm). compound 130 was reported to be the "first marine-derived acetylcholinesterase-inhibiting steroidal alkaloid" with a mechanism of action involving an unusual mixed-competitive mode of inhibition. choi et al. (2007) extended the molecular pharmacology of two known meroditerpenes, sargaquinoic acid (131) and sargachromenol (132) isolated from the brown alga s. sagamianum. sargaquinoic acid potently inhibited butyrylcholinesterase (ic 50 = 26 nm), a novel target for the treatment of alzheimer's disease, with potency comparable to or greater than anticholinesterases in current clinical use. hui et al. (2008) further characterized the neuroprotective effects of the polysaccharide sulfated polymannuroguluronate (spmg) (74), noted earlier as currently being in phase ii clinical trials in china as an anti-aids drug candidate. spmg appeared to decrease the tat-stimulated calcium overload in pc12 neuronal cells as well as concomitant apoptosis-signaling cascades, thus demonstrating a potential for further clinical development as a therapeutic intervention in hivassociated dementia. table 3 lists 65 marine compounds with miscellaneous pharmacological mechanisms of action, and their respective structures (133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197) are presented in fig. 3 . because during 2007-8 additional pharmacological data were unavailable, it was not possible to assign these marine compounds to a particular drug class as was possible with the compounds included in tables 1 and 2. table 3 shows 14 marine natural products that the peer-reviewed literature reported with a pharmacological activity, an ic 50 , and a molecular mechanism of action affected by the respective compound: azumamide e (133), 1-deoxyrubralactone (134), fucoxanthin (135), okadaic acid (136), saproxanthin and myxol (137, 138), sarcomilasterol (139), spirastrellolides c, d, and e (140, 141, 142), spongia sesterterpenoid (143), stylissadines a and b (144, 145) and symbiodinolide (146). in contrast, although a pharmacological activity was described, and an ic 50 for inhibition of an enzyme or receptor determined, detailed molecular mechanism of action studies were unavailable at the time of publication for the following 51 marine compounds included in table 3 : asterias amurensis saponin (147), botrytis sp. α-pyrone derivative (148) (185), sargassum siliquastrum meroditerpenoids (186, 187, 188, 189, 190, 191) , symphyocladia latiuscula bromophenols (192, 193, 194, 195) , and tenacibactins c and d (196, 197) . several reviews covering both general and specific subject areas of marine pharmacology were published during 2007-8: (a) general marine pharmacology: marine natural products with an emphasis on source organisms and relevant biological activities (blunt et al., 2007 (blunt et al., , 2008 ; the value of natural products to future pharmaceutical discovery ; the structures and bioactivities of secondary metabolites from cyanobacteria (gademann and portmann, 2008) ; bioactive natural products from marine cyanobacteria for drug discovery (tan l.t., 2007) ; bioactive compounds from fungi in the south china sea (pan et al., 2008) ; biochemical and pharmacological functions of β-carboline alkaloids (cao et al., 2007) ; pharmacological properties of lamellarin alkaloids (kluza et al., 2008) ; biological activity of brown seaweed fucoidans (kusaykin et al., 2008; ; potential pharmacological uses of the marine green alga polysaccharide ulvan (lahaye and robic, 2007) ; pharmacological properties of marine bis-and tris-indole alkaloids (gupta et al., 2007) ; (b) antimicrobial marine pharmacology: a renaissance of genomics in antibacterial discovery from actinomycetes (baltz r.h., 2008) ; mining marine genomics for novel drug discovery from phytosymbionts of marine invertebrates (dunlap et al., 2007) ; (c) anticoagulant and cardiovascular pharmacology: structure, biology, evolution and medical importance of sulfated fucans and galactans as potential antithrombotic compounds (pomin and mourao, 2008) ; (d) antituberculosis, antimalarial and antifungal marine pharmacology: natural product growth inhibitors of mycobacterium tuberculosis (copp and pearce, 2007) ; new advances in novel marine fatty acids as antimalarials, antimycobacterial and antifungal agents (carballeira n.m., 2008) ; depsipeptides from microorganisms as a new class of antimalarials (fotie and morgan, 2008) ; the manzamine alkaloids for the control of malaria and tuberculosis (hamann m.t., 2007) ; (e) immuno-and anti-inflammatory marine pharmacology: chemistry and biology of anti-inflammatory marine natural products (abad et al., 2008) ; marine natural products as targeted modulators of the transcription factor nf-κb (folmer et al., 2008) ; glycolipids as immunostimulating agents ); (f) nervous system marine pharmacology: marine-derived drugs in neurology (martinez a., 2007) ; neuritogenic gangliosides from marine echinoderms (higuchi et al., 2007) ; (g) miscellaneous molecular targets: enzyme inhibitors from marine invertebrates (nakao and fusetani, 2007) ; natural products as aromatase inhibitors (balunas et al., 2008) ; biology of the aeruginosin family of serine protease inhibitors (ersmark et al., 2008) ; and marine natural products affecting membrane and intracellular processes, and ion channels (folmer et al., 2007) . six years after the approval of the marine compound ziconotide (prialt®) by the u.s. food and drug administration (williams et al., 2008) , the global marine preclinical pharmaceutical pipeline remains very active. the marine pharmaceutical clinical pipeline is available at http://marinepharmacology.midwestern.edu/clindev.htm and has recently been reviewed (mayer et al., 2010) . the current marine preclinical pipeline review contributes to the annual review series which was initiated in 1998 (mayer and lehmann, 2000; mayer and hamann, 2002 , 2005 mayer et al., 2007 mayer et al., , 2009 ) and reveals the breadth of preclinical pharmacological research during 2007-8, which resulted from the global effort of natural products chemists and pharmacologists from argentina, australia, brazil, canada, china, egypt, france, germany, india, israel, italy, japan, the netherlands, new zealand, panama, papua new guinea, portugal, russia, south korea, spain, switzerland, taiwan, thailand, turkey, united kingdom, vietnam, and the united states. thus, it appears that the marine preclinical pharmaceutical pipeline continues to contribute novel pharmacological lead compounds that will probably enable a future expansion of the marine clinical pharmaceutical pipeline, which currently consists of 13 compounds in phase i, ii and iii of clinical development (mayer et al., 2010) . natural marine anti-inflammatory products chaetominedione, a new tyrosine kinase inhibitor isolated from the algicolous marine fungus chaetomium sp isolation and structure determination of malevamide e, a dolastatin 14 analogue, from the marine cyanobacterium symploca laete-viridis immunomodulatory effects of an enzymatic extract from ecklonia cava on murine splenocytes damipipecolin and damituricin, novel bioactive bromopyrrole alkaloids from the mediterranean sponge axinella damicornis immunomodulatory properties of frondoside a, a major triterpene glycoside from the north atlantic commercially harvested sea cucumber cucumaria frondosa isolation and structures of erylosides from the caribbean sponge erylus formosus anti-hiv-1 activity of phloroglucinol derivative, 6, 6′-bieckol, from ecklonia cava biological effects of a sulfated-polysaccharide isolated from the marine red alga champia feldmannii the value of natural products to future pharmaceutical discovery renaissance in antibacterial discovery from actinomycetes natural products as aromatase inhibitors the marine sponge plakortis zyggompha: a source of original bioactive polyketides disturbance of voltage-induced cellular calcium entry by marine dimeric and tetrameric pyrrole-imidazole alkaloids antinociceptive and antiinflammatory effects of a mucin-binding agglutinin isolated from the red marine alga hypnea cervicornis marine natural products marine natural products eurysterols a and b, cytotoxic and antifungal steroidal sulfates from a marine sponge of the genus euryspongia actinomycetes from sediments in the trondheim fjord, norway: diversity and biological activity the crosslinking and antimicrobial properties of tunichrome β-carboline alkaloids: biochemical and pharmacological functions new advances in fatty acids as antimalarial, antimycobacterial and antifungal agents protein phosphatase inhibitors isolated from spongia irregularis collected in papua new guinea monoglycerides from the brown alga sargassum sagamianum: isolation, synthesis, and biological activity cytotoxic and anti-inflammatory cembranoids from the soft coral lobophytum crassum polysaccharides from gracilaria corticata: sulfation, chemical characterization and anti-hsv activities durumolides a-e, anti-inflammatory and antibacterial cembranolides from the soft coral lobophytum durum anticholinesterase activity of plastoquinones from sargassum sagamianum: lead compounds for alzheimer's disease therapy studies on puupehenone-metabolites of a dysidea sp.: structure and biological activity the dolabellane diterpene dolabelladienetriol is a typical noncompetitive inhibitor of hiv-1 reverse transcriptase enzyme natural products chemistry and taxonomy of the marine cyanobacterium blennothrix cantharidosmum natural product growth inhibitors of mycobacterium tuberculosis floridoside extracted from the red alga mastocarpus stellatus is a potent activator of the classical complement pathway 19-epi-okadaic acid, a novel protein phosphatase inhibitor with enhanced selectivity isolation and structural elucidation of callipeltins j-m: antifungal peptides from the marine sponge latrunculia sp anti-inflammatory constituents of the red alga gracilaria verrucosa and their synthetic analogues antimicrobial potential of a lipopeptide biosurfactant derived from a marine bacillus circulans a sars-coronovirus 3cl protease inhibitor isolated from the marine sponge axinella cf. corrugata: structure elucidation and synthesis isolation and structural characterization of two antibacterial free fatty acids from the marine diatom, phaeodactylum tricornutum tauramamide, a lipopeptide antibiotic produced in culture by brevibacillus laterosporus isolated from a marine habitat: structure elucidation and synthesis bioprotective properties of seaweeds: in vitro evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content three new antimicrobial metabolites of phomopsis sp highly brominated mono-and bis-phenols from the marine red alga symphyocladia latiuscula with radical-scavenging activity biomedicinals from the phytosymbionts of marine invertebrates: a molecular approach semisynthetic studies on the manzamine alkaloids cyp3a4 inhibitors isolated from a marine derived fungus penicillium species essramycin: a first triazolopyrimidine antibiotic isolated from nature novel bioactive metabolites from a marine derived bacterium nocardia sp. alaa chemistry and biology of the aeruginosin family of serine protease inhibitors antibiotics for emerging pathogens biomedical research tools from the seabed marine natural products as targeted modulators of the transcription factor nf-κb depsipeptides from microorganisms: a new class of antimalarials antileishmanial properties of tropical marine algae extracts secondary metabolites from cyanobacteria: complex structures and powerful bioactivities isomeric furanosesquiterpenes from the portuguese marine sponge fasciospongia sp t-antigen binding lectin with antibacterial activity from marine invertebrate, sea cucumber (holothuria scabra): possible involvement in differential recognition of bacteria new iantherans from the marine sponge ianthella quadrangulata: novel agonists of the p2y(11) receptor bioactive metabolites from the caribbean sponge aka coralliphagum chemical transformation and biological studies of marine sesquiterpene (s)-(+)-curcuphenol and its analogs bis-and tris-indole alkaloids from marine organisms: new leads for drug discovery the manzamines as an example of the unique structural classes available for the discovery and optimization of infectious disease controls based on marine natural products linckosides m-q: neuritogenic steroid glycosides from the okinawan starfish linckia laevigata polybrominated diphenyl ethers from the indonesian sponge lamellodysidea herbacea isolation and structural characterization of a novel polysaccharide prepared from arca subcrenata lischke biologically active gangliosides from echinoderms antibacterial quinone metabolite from the brown alga, sargassum sagamianum batzelladine alkaloids from the caribbean sponge monanchora unguifera and the significant activities against hiv-1 and aids opportunistic infectious pathogens three different hepcidins from tilapia, oreochromis mossambicus: analysis of their expressions and biological functions the marinopyrroles, antibiotics of an unprecedented structure class from a marine streptomyces sp prodigiosin isolated from hahella chejuensis suppresses lipopolysaccharide-induced no production by inhibiting p38 mapk, jnk and nf-kappab activation in murine peritoneal macrophages sulfated polymannuroguluronate, a novel anti-acquired immune deficiency syndrome drug candidate, decreased vulnerability of pc12 cells to human immunodeficiency virus tat protein through attenuating calcium overload pheophytin a, a low molecular weight compound found in the marine brown alga sargassum fulvellum, promotes the differentiation of pc12 cells tenacibactins a-d, hydroxamate siderophores from a marine-derived bacterium, tenacibaculum sp. a4k-17 pseudoceratins a and b, antifungal bicyclic bromotyrosine-derived metabolites from the marine sponge pseudoceratina purpurea aaptamines as sortase a inhibitors from the tropical sponge aaptos aaptos structures and absolute configurations of sulfateconjugated triterpenoids including an antifungal chemical defense of the green macroalga tydemania expeditionis sulfated polysaccharide purified from ecklonia cava accelerates antithrombin iii-mediated plasma proteinase inhibition a novel anticoagulant protein with high affinity to blood coagulation factor va from tegillarca granosa meroditerpenoids from the brown alga sargassum siliquastrum new sulfoalkylresorcinol from marine-derived fungus, zygosporium sp. knc52 ascochytatin, a novel bioactive spirodioxynaphthalene metabolite produced by the marine-derived fungus, ascochyta sp. ngb4 antimicrobial activity of volatile components and various extracts of the red alga jania rubens cytotoxic and antiplasmodial substances from marine-derived fungi, nodulisporium sp. and cri247-01 suppression of ap-1 activity by cycloprodigiosin hydrochloride isolation of two anti-inflammatory and one pro-inflammatory polyunsaturated fatty acids from the brown seaweed undaria pinnatifida sulfated steroid glycosides from the vietnamese starfish linckia laevigata new neuritogenic teroid glycosides from the vietnamese starfish linckia laevigata symbiodinolide, a novel polyol macrolide that activates n-type ca 2+ channel, from the symbiotic marine dinoflagellate symbiodinium sp identification of an antibacterial protein as l-amino acid oxidase in the skin mucus of rockfish sebastes schlegeli antibacterial action of l-amino acid oxidase from the skin mucus of rockfish sebastes schlegelii lamellarin alkaloids: structure and pharmacological properties carteramine a, an inhibitor of neutrophil chemotaxis, from the marine sponge stylissa carteri complete structure elucidation of shishididemniols, complex lipids with tyramine-derived tether and two serinol units, from a marine tunicate of the family didemnidae new metabolites with antibacterial activity from the marine angiosperm cymodocea nodosa antiparasitic, antineuroinflammatory, and cytotoxic polyketides from the marine sponge plakortis angulospiculatus collected in brazil potential cancer chemopreventive in vitro activities of monomeric xanthone derivatives from the marine algicolous fungus monodictys putredinis nagelamides m and n, new bromopyrrole alkaloids from sponge agelas species antifungal activity in triterpene glycosides from the sea cucumber actinopyga lecanora pedein a and b: production, isolation, structure elucidation and biological properties of new antifungal cyclopeptides from chondromyces pediculatus (myxobacteria) structure, biological activity, and enzymatic transformation of fucoidans from the brown seaweeds pf1270a, b and c, novel histamine h3 receptor ligands produced by penicillium waksmanii pf1270 structure and functional properties of ulvan, a polysaccharide from green seaweeds callophycoic acids and callophycols from the fijian red alga callophycus serratus acetylcholinesterase-inhibiting steroidal alkaloid from the sponge corticium sp inhibition of the pathogenicity of magnaporthe grisea by bromophenols, isocitrate lyase inhibitors, from the red alga odonthalia corymbifera solution structures and biological functions of the antimicrobial peptide, arenicin-1, and its linear derivative inhibition of candida albicans isocitrate lyase activity by sesterterpene sulfates from the tropical sponge dysidea sp natural bromophenols from the marine red alga polysiphonia urceolata (rhodomelaceae): structural elucidation and dpph radical-scavenging activity cephalosporolides h and i, two novel lactones from a marine-derived fungus, penicillium sp fucoidan: structure and bioactivity bromophenols from the marine red alga polysiphonia urceolata with dpph radical scavenging activity cathepsin b inhibitory activities of three new phthalate derivatives isolated from seahorse venturamides a and b: antimalarial constituents of the panamanian marine cyanobacterium oscillatoria sp two new steroidal compounds from starfish asterias amurensis lutken antioxidant alkaloid from the south china sea marine sponge iotrochota sp sulfated polymannuroguluronate, a novel anti-aids drug candidate, inhibits hiv-1 tatinduced angiogenesis in kaposi's sarcoma cells anti-inflammatory cembranoids from the soft corals sinularia querciformis and sinularia granosa lipoxazolidinones a, b, and c: antibacterial 4-oxazolidinones from a marine actinomycete isolated from a guam marine sediment anti-herpetic activity of a sulfated xylomannan from scinaia hatei new bioactive hydrogenated linderazulene-derivatives from the gorgonian echinogorgia complexa heparinoid-active two sulfated polysaccharides isolated from marine green algae monostroma nitidum marine-derived drugs in neurology antimicrobial and cytotoxic assessment of marine cyanobacteria -synechocystis and synechococcus lyngbyastatin 4, a dolastatin 13 analogue with elastase and chymotrypsin inhibitory activity from the marine cyanobacterium lyngbya confervoides pompanopeptins a and b, new cyclic peptides from the marine cyanobacterium lyngbya confervoides molecular insights into azumamide e histone deacetylases inhibitory activity marine pharmacology in 1998 antitumor and cytotoxic compounds marine pharmacology in 2000: antitumor and cytotoxic compounds marine pharmacology in 2001-2: antitumour and cytotoxic compounds marine pharmacology in 2003-2004: anti-tumour and cytotoxic compounds marine pharmacology in 2005-2006: antitumour and cytotoxic compounds marine pharmacology in 1999: compounds with antibacterial, anticoagulant, antifungal, anti-inflammatory, anthelmintic, antiinflammatory, antiplatelet, antiprotozoal and antiviral activities;affecting the cardiovascular, endocrine, immune, and nervous systems; and other miscellaneous mechanisms of action marine pharmacology in 2000: marine compounds with antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiplatelet, antituberculosis, and antiviral activities; affecting the cardiovascular, immune, and nervous systems and other miscellaneous mechanisms of action marine pharmacology in 2001-2002: marine compounds with anthelmintic, antibacterial, anticoagulant, antidiabetic, antifungal, anti-inflammatory, antimalarial, antiplatelet, antiprotozoal, antituberculosis, and antiviral activities; affecting the cardiovascular, immune and nervous systems and other miscellaneous mechanisms of action marine pharmacology in 1998: marine compounds with antibacterial, anticoagulant, antifungal, anti-inflammatory, anthelmintic, antiplatelet, antiprotozoal, and antiviral activities; with actions on the cardiovascular, endocrine, immune, and nervous systems; and other miscellaneous mechanisms of action marine pharmacology in 1999: antitumor and cytotoxic compounds marine pharmacology in 2003-4: marine compounds with anthelmintic antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiplatelet, antiprotozoal, antituberculosis, and antiviral activities; affecting the cardiovascular, immune and nervous systems, and other miscellaneous mechanisms of action marine pharmacology in 2005-6: marine compounds with anthelmintic, antibacterial, anticoagulant, antifungal, anti-inflammatory, antimalarial, antiprotozoal, antituberculosis, and antiviral activities; affecting the cardiovascular, immune and nervous systems, and other miscellaneous mechanisms of action the odyssey of marine pharmaceuticals: a current pipeline perspective lynamicins a-e, chlorinated bisindole pyrrole antibiotics from a novel marine actinomycete antimalarial linear lipopeptides from a panamanian strain of the marine cyanobacterium lyngbya majuscula evaluation of selected tropical seaweeds for in vitro anti-trichomonal activity a new antimalarial polyether from a marine streptomyces sp. h668 1-deoxyrubralactone, a novel specific inhibitor of families x and y of eukaryotic dna polymerases from a fungal strain derived from sea algae marine algae: screening for a potent antibacterial agent enzyme inhibitors from marine invertebrates scalarane sesterterpenes from a marine sponge of the genus spongia and their fxr antagonistic activity dehydroxychlorofusarielin b, an antibacterial polyoxygenated decalin derivative from the marine-derived fungus aspergillus sp promotion of il-8 production in pma-stimulated hl-60 cells by sesquiterpene quinones from a marine sponge, hippospongia sp thalassospiramides a and b, immunosuppressive peptides from the marine bacterium thalassospira sp salinipyrones and pacificanones, mixed-precursor polyketides from the marine actinomycete salinispora pacifica ariakemicins a and b, novel polyketide-peptide antibiotics from a marine gliding bacterium of the genus rapidithrix bipinnapterolide b, a bioactive oxapolycyclic diterpene from the colombian gorgonian coral pseudopterogorgia bipinnata review of bioactive compounds from fungi in the south china sea anti-inflammatory thiazine alkaloids isolated from the new zealand ascidian aplidium sp.: inhibitors of the neutrophil respiratory burst in a model of gouty arthritis e/z-rubrolide o, an anti-inflammatory halogenated furanone from the new zealand ascidian synoicum n. sp alpha4/ 7-conotoxin lp1.1 is a novel antagonist of neuronal nicotinic acetylcholine receptors mirabamides a-d, depsipeptides from the sponge siliquariaspongia mirabilis that inhibit hiv-1 fusion structure, biology, evolution, and medical importance of sulfated fucans and galactans spongian diterpenoids from the sponge spongia (heterofibria) sp antiprotozoal activities of heterocyclic-substituted xanthones from the marine-derived fungus chaetomium sp monodictyochromes a and b, dimeric xanthone derivatives from the marine algicolous fungus monodictys putredinis isolation and purification of an anticoagulant from fermented red seaweed lomentaria catenata lipid extract of nostoc commune var. sphaeroides kutzing, a blue-green alga, inhibits the activation of sterol regulatory element binding proteins in hepg2 cells antimicrobial ambiguines from the cyanobacterium fischerella sp. collected in israel new c-secosteroids from the gorgonian tripalea clavaria extending the record of meroditerpenes from cacospongia marine sponges radical scavenging and singlet oxygen quenching activity of marine carotenoid fucoxanthin and its metabolites cdna sequence and tissue expression of an antimicrobial peptide, dicentracin; a new component of the moronecidin family isolated from head kidney leukocytes of sea bass, dicentrarchus labrax an antiproliferative bis-prenylated quinone from the new zealand brown alga perithalia capillaris antimycobacterial activity of the red alga polysiphonia virgata antitumor and cytotoxic compounds from marine organisms biosynthesis and structures of cyclomarins and cyclomarazines, prenylated cyclic peptides of marine actinobacterial origin four new briarane diterpenoids from the gorgonian coral junceella fragilis diapolycopenedioic acid xylosyl ester, a novel glyco-c 30 -carotenoic acid produced by a new marine bacterium rubritalea squalenifaciens viridamides a and b, lipodepsipeptides with antiprotozoal activity from the marine cyanobacterium oscillatoria nigro-viridis anti-allergic phlorotannins from the edible brown alga, eisenia arborea isolation and characterization of okadaic acid binding proteins from the marine sponge halichondria okadai screening for antibacterial and antifungal activities in marine benthic invertebrates from northern norway an algalderived dl-galactan hybrid is an efficient preventing agent for in vitro dengue virus infection bioactive natural products from marine cyanobacteria for drug discovery lyngbyastatins 5-7, potent elastase inhibitors from floridian marine cyanobacteria, lyngbya spp kempopeptins a and b, serine protease inhibitors with different selectivity profiles from a marine cyanobacterium, lyngbya sp marine natural products from the turkish sponge agelas oroides that inhibit the enoyl reductases from plasmodium falciparum, mycobacterium tuberculosis and escherichia coli novel anti-inflammatory omega-3 pufas from the new zealand greenlipped mussel, perna canaliculus the isolation, purification and biological activity of a novel antibacterial compound produced by pseudomonas stutzeri antibacterial activity of halogenated sesquiterpenes from malaysian laurencia spp a new 9, 11-secosterol from the vietnamese sea soft coral, sarcophyton mililatensis, increases the function of osteoblastic mc3t3-e1 cells a malespecific expression gene, encodes a novel anionic antimicrobial peptide, scygonadin, in scylla serrata structural features and anti-hiv-1 activity of novel polysaccharides from red algae grateloupia longifolia and grateloupia filicina antifungal activity evaluation of the constituents of haliclona baeri and haliclona cymaeformis, collected from the gulf of thailand caribenols a and b, sea whip derived norditerpenes with novel tricarbocyclic skeletons novel ring b abeo-sterols as growth inhibitors of mycobacterium tuberculosis isolated from a caribbean sea sponge, svenzea zeai paeciloxanthone, a new cytotoxic xanthone from the marine mangrove fungus paecilomyces sp spirastrellolides c to g: macrolides obtained from the marine sponge spirastrella coccinea saliniketals a and b, bicyclic polyketides from the marine actinomycete salinispora arenicola ziconotide: an update and review neopeltolide, a macrolide from a lithistid sponge of the family neopeltidae glycolipids as immunostimulating agents antibacterial and antilarval activity of deep-sea bacteria from sediments of the west pacific ocean cell-adhesion inhibitors produced by sea hare-derived periconia sp. iii. absolute stereostructures of peribysins j and macrosphelide m a sulfated fucan from the brown alga laminaria cichorioides has mainly heparin cofactor ii-dependent anticoagulant activity a new α-pyrone derivative, 6-[(e)-hept-1-enyl]-α-pyrone, with tyrosinase inhibitory activity from a marine isolate of the fungus botrytis circumdatin i, a new ultraviolet-a protecting benzodiazepine alkaloid from a marine isolate of the fungus exophiala isolation, structure elucidation, and antimycobacterial properties of dimeric naphtho-γ-pyrones from the marine-derived fungus aspergillus carbonarius this review was made possible with financial support from midwestern university to amsm; nih-sc1 award (grant 1sc1gm086271-01a1) of the university of puerto rico to adr; and fapesp grant 05/60175-2 (são paulo, brazil) to rgsb. the content of this review is solely the responsibility of the authors and does not necessarily represent the official views of the nih. assistance with extensive searches of the 2007-8 marine pharmacology literature in pubmed, marinlit, current contents® and chemical abstracts®, as well as article retrieval by library staff members, and students from the chicago college of pharmacy, midwestern university, are gratefully acknowledged. the authors are especially thankful to ms. mary hall for the careful review of the manuscript. key: cord-283301-adjjkqt2 authors: awolade, paul; cele, nosipho; kerru, nagaraju; gummidi, lalitha; oluwakemi, ebenezer; singh, parvesh title: therapeutic significance of β-glucuronidase activity and its inhibitors: a review date: 2020-02-01 journal: eur j med chem doi: 10.1016/j.ejmech.2019.111921 sha: doc_id: 283301 cord_uid: adjjkqt2 the emergence of disease and dearth of effective pharmacological agents on most therapeutic fronts, constitutes a major threat to global public health and man’s existence. consequently, this has created an exigency in the search for new drugs with improved clinical utility or means of potentiating available ones. to this end, accumulating empirical evidence supports molecular target therapy as a plausible egress and, β-glucuronidase (βglu) – a lysosomal acid hydrolase responsible for the catalytic deconjugation of β-d-glucuronides has emerged as a viable molecular target for several therapeutic applications. the enzyme’s activity level in body fluids is also deemed a potential biomarker for the diagnosis of some pathological conditions. moreover, due to its role in colon carcinogenesis and certain drug-induced dose-limiting toxicities, the development of potent inhibitors of βglu in human intestinal microbiota has aroused increased attention over the years. nevertheless, although our literature survey revealed both natural products and synthetic scaffolds as potential inhibitors of the enzyme, only few of these have found clinical utility, albeit with moderate to poor pharmacokinetic profile. hence, in this review we present a compendium of exploits in the present millennium directed towards the inhibition of βglu. the aim is to proffer a platform on which new scaffolds can be modelled for improved βglu inhibitory potency and the development of new therapeutic agents in consequential. the world today is embattled with an increasing paucity of effective therapeutic agents or regimen for many pathological conditions, as well as the menace of drug resistance and adverse effects of available drugs [1] . as a result, smooth and efficient clinical practice is rigidly stymied, while global public health, social security and man's life expectancy are seriously threatened and trickles to a disquieting edge [2] . likewise, the burdens of developing new therapeutic agents to ameliorate the status quo has become heavier on all stakeholders in drug research. in this regard, molecular target therapy is fast becoming a spearhead in the search for new drugs with improved therapeutic effects. amongst many targets explored, glycosyl hydrolases (ghs) are notable due to their role in many important biological processes. their principal function is to catalytically cleave the glycosidic bond of glycans thereby eliciting different physiological responses. therefore, inhibitors of this class of enzymes have enjoyed intense research and development owing to their potentials as antiviral, anticancer and antidiabetic agents as well as therapeutic agents for some genetic disorders [3e5] . ghs have been classified using different indices [6] . for example, based on substrate specificity, those cleaving o-or sglycosides are grouped into ec 3.2.1 class, while hydrolases of nglycosides belong to ec 3.2.2 class. advancements in genomic science have also enabled classification into gh families based on their amino acid sequence similarities [7] . this system further groups gh families into clans, given the improved conservation of protein fold than the sequence [8] . accordingly, the reviewed enzyme, b-glucuronidase (ec 3.2.1.31) is classified into gh family 1, 2, 30, 79, 154 and gh-a clan. b-glucuronidase (bglu) is mainly a lysosomal hydrolase widely distributed in mammalian tissues, body fluids and microbiota; but significantly retained in the endoplasmic reticulum [9] . the enzyme is also found in plants, fishes, insects and molluscs. specifically, human bglu belongs to gh family 2. it is a 332 kda ellipsoidal and homotetrameric glycoprotein with each 75e78 kda monomer containing 651 amino acid residues (fig. 1a) . the monomer precursor is synthesized initially on membrane-bound ribosomes and suffers c-terminal proteolytic processing of 18 amino acid propeptide en route or after their transport to the lysosomes [10e13]. x-ray crystallography of the protein structure reveals a dihedral symmetry for the tetramer with two identical monomers in the asymmetric unit arising from disulphide-linked dimers. each monomer contains three structural domains (fig. 1b) . the first domain has a barrel-like structure with a jelly roll motif; the second domain exhibits a geometry identical to immunoglobulin constant domains; while the third c-terminal domain forms a tim barrel motif (b/a) 8 [14] . the active sites of human bglu ( fig. 1c) viz. catalytic acid glu451 (proton donor), catalytic nucleophile glu540 (carbonium ion stabilizer), asp207 (plausible role as glu540) and tyr504 (unclear catalytic role), are all housed in the third domain and in each of the four catalytic centres of the tetramer [14, 15] . moreover, the enzyme has an optimal activity at acidic ph~4.5, corresponding to its lysosomal environment and thermally stable up to 70 c [10] ; although hyperthermophilic variants exists in other media [16] . bglu is encoded by the gus gene. a deficiency arising from mutations in this encoding gene is associated with atherosclerosis [17] and lysosomal storage disease e sly syndrome or mucopolysaccharidosis type vii [18] . on the other hand, bacterial bglu, which is expressed in human gut microbiota and most strains of escherichia coli shows 45% sequence similarity with human bglu. also, it has a bacterial loop containing 17-amino acid residues not found in human bglu, an optimal activity at neutral ph and active site catalytic residues as glu413 (catalytic acid) and glu504 (catalytic nucleophile) [19] . consistent with the activities of lysosomal ghs, bglu deconjugates b-d-glucuronides to their corresponding aglycone and b-dglucuronic acid via an s n 2 reaction and "configuration retaining" mechanism ( fig. 2) . the catalytic mechanism is conceived to proceed as follows; catalytic glutamic acid residue glu451 (or glu413 in bacterial ortholog) protonates exocyclic glycosidic oxygen of glucuronide (1) hence releasing the aglycone via a putative oxocarbenium ion-like transition state (2) . 'back-side' nucleophilic attack by glutamate ion glu540 (or glu504 in bacterial ortholog) e the catalytic nucleophile, stabilizes the transition state and results in glucuronyl ester intermediate (3) with an inverted configuration. finally, hydrolysis through an inverting attack of water molecule on the anomeric centre releases glu540 to form b-d-glucuronic acid (4) and a concurrent overall retention of substrate configuration [14,15,19e21 ]. due to the increased expression of bglu in necrotic areas and other body fluids of patients with different forms of cancer such as breast [22] , cervical [23] , colon [24] , lung [25] , renal carcinoma and leukaemia [26] , compared to healthy controls, the enzyme is proffered as a reliable biomarker for tumour diagnosis and clinical therapy assessment [27] . this overexpression is also a potential diagnostic tool for other disease states such as urinary tract infection [28] , hiv [29] , diabetes [30] , neuropathy [31] and rheumatoid arthritis [32] . in this vein, empirical data update on clinical applications of bglu for these and other disorders is provided on brenda database [33] . bglu activity is also harnessed in prodrug monotherapy. in normal body systems, drugs and other xenobiotics are detoxified via glucuronidation, an s n 2 conjugation reaction and important pathway in phase ii metabolism, catalysed by udpglucuronosyltransferases (ugts). the resulting usually less active glucuronide metabolite is readily excreted by renal clearance due to increased polarity or sometimes via biliary clearance [34] . however, elevated levels of bglu activity reverts this process through deglucuronidation, which hydrolyses the phase ii metabolites to their active forms (fig. 2) . hence, glycosidation of a drug to give its glucuronide enhances selective release of the active form at necrotic sites via bglu-mediated deglucuronidation thus improving the drug's therapeutic potential [35] . bglu's postulated ability to increase t regulator cells (treg) is also applied in low-dose immunotherapy (ldi) for managing allergic diseases [36, 37] , lyme disease [38] and other chronic conditions. while it's hydrolytic activity on glucuronide conjugates is harnessed in forensic analysis [39] and assessment of microbial water quality [40] . nonetheless, enterobacterial bglu deconjugation of drug and xenobiotic glucuronides in the gastrointestinal (gi) tract has been implicated in colonic genotoxicity [41] and certain drug-induceddose-limiting toxicities. for example, the gi toxicity of anticancer drug irinotecan (cpt-11) [42] , enteropathy of non-steroidal antiinflammatory drug (nsaid) diclofenac [43] , tissue inflammation and hepatoxicity. furthermore, bglu is deemed a potential molecular target for; (1) anticancer chemotherapy considering its role in tumour growth and metastasis [44, 45] . (2) neonatal jaundice treatment due to its high expression in breast milk and role in enterohepatic bilirubin circulation (hyperbilirubinemia) [46, 47] . (3) diabetes mellitus management consequent to the positive correlations between the disease state and enzyme activity level as well as associated periodontitis [48, 49] . (4) anti-inflammatory agents development owing to its pro-inflammatory role following significant release from degranulated mast cells and neutrophils [50, 51] . expectedly, inhibition of bglu markedly alleviated these pathological conditions and their adverse effects hence improving regimens' efficacy. based on the foregoing, we extrapolate that the development of potent, specific and non-cytotoxic inhibitors of bglu is imperative to improving the clinical efficacy of therapeutic agents and effective disease management while bearing in mind the physiological significance of both human and bacterial orthologs of the glycosyl hydrolase. however, the fate of these inhibitors rests on their inhibition constants (k i ), since ghs are generally characterized by high rate enhancement (k cat /k uncat > 10 17 -fold). also, accumulating evidence suggests the dependence of inhibitory potency on the ability to mimic the highly enzyme-stabilized transition state of an enzymatic reaction (k i z 10 à20 m) en route to catalytic product [21, 52, 53] . considering the proven and encouraging potentials of enzyme inhibition and molecular target therapy in drug development, and in continuation of our exploits and expositions thereon [54e58], herein we present a comprehensive review of research undertakings in the present millennium (2000e2019) directed towards the development of potent inhibitors of bglu that are either natural products or synthetic scaffolds. apropos, before discussing the different inhibitors, this article will first highlight the potentials of bglu activity as a diagnostic tool within the defined period. however, therapeutic application in prodrug monotherapy and enzyme replacement therapy (ert) will not be covered as these have been excellently treated in other reviews [59e61]. hitherto, our search of extant literature revealed that, although there exists a plethora of scholarly research on potential inhibitors of bglu activity, no review article is exclusively devoted to the subject matter. the aim of this review is therefore to bring to light those bioactive frameworks bestowed with promising bglu inhibitory potency. our principal goal is to intimate the reader on key structural features of reviewed molecules crucial to their inhibitory activities and toxicity profiles, while establishing the comprehensive relationships existing between reported molecules. the availability of safe, easy to use, consistent, less-invasive and cost-effective tool for early diagnosis of diseases or appraisal of therapeutic interventions is of uttermost importance in clinical medicine. since most disease states are accompanied by elevated levels of specific enzymes in the diseased milieu (tissues, plasma and other body fluids), quantification of enzymes' activity levels is seen as a reliable biomarker of either disease status, severity, effects, susceptibility or exposure [62e64]. moreover, the substrate specificity and selective quantification of enzymes in the presence of other biomolecules makes them a tool of choice thereto [65] . a review of bglu activity as a biomarker of some physiologically important conditions is hereby presented together with a concise summary in table 1 . periodontal disease is a group of inflammatory disorders triggered by host's immune response to the actions of virulent subgingival plaque bacteria biofilms which activates the release of polymorphonuclear leukocytes and macrophages into the gingival crevice. this leads to gingivitis e an inflammation of periodontal tissues and distortion of periodontal histology that is reversible with improved oral hygiene; or, subsequent tissue destruction, alveolar bone resorption and tooth loss if left unattended i.e. periodontitis [66, 67] . therefore, a reliable tool to ascertain disease status, severity, risk or efficacy of administered therapy is highly desirous to clinicians. however, conventional diagnosis involving the measurement of periodontal clinical parameters such as probing depth (pd), clinical attachment level (cal), gingival index (gg-i), bleeding on probing (bop) and alveolar bone loss (abl), suffers from intrinsic limitations. they only define the status of patient's periodontium at the time of examination and not periodontal disease susceptibility or risk [68] . thus, since periodontitis is characterized by an influx of inflammatory mediators and corresponding enzymes into the gingival sulcus, the quantification of neutrophil-derived bglu activity in gingival crevicular fluid (gcf) or gcf's outflow into the oral cavity and subsequent less invasive estimation of bglu activity in saliva is considered a reliable biomarker for periodontal disease diagnosis. to this effect, the relationship between salivary bglu activity and periodontal clinical parameters (pd, cal and gg-i) was investigated in subjects with different stages of periodontal disease [69] . the mean pd and gg-i, number of sites with pd ! 5 mm and total number of white blood cells, blood neutrophils and monocytes all showed highly significant correlations with enzyme's activity, while cal had a weaker correlation. using logistic regression modelling and the presence of at least 1 or 4 sites with pd ! 5 mm as disease criterion, bglu activity showed promising potentials as a tool for periodontal disease screening or assessment of therapeutic intervention. the study also observed smoking status to be insignificant on enzyme activity. however, in a similar study, only pd, cal and lymphocyte count exhibited positive correlation with salivary enzyme activity while no significant relationship was observed for gg-i [70] . recently, subjects with chronic generalized periodontitis were also found to have significant increase in bglu activity (8-fold) compared to normal ones. although, a reduction in enzyme activity persisted in smokers regardless of periodontal status [71] . table 1 reported potential applications of bglu activity as a biomarker. [112] 284** ache activity chronic exposure (w) acute exposure (n) elevated in 16.5% and 60% of subjects with chronic and acute exposure respectively [113] ns: not specified; w: weak correlation; n: no correlation; pi: russell periodontal index; *threshold to distinguish culture positive from culture negative balf; ** acute exposure (5), chronic exposure (230) . the efficacy of therapeutic intervention using amoxicillin and metronidazole to downregulate amplified neutrophil activity was studied in 14 patients with aggressive periodontitis [72] . treatment involved seven consecutive days of antibiotic administration with concurrent scaling, root planning and surgical therapy and a total of 36 months posttreatment evaluation period. subsequently, a markedly downregulated neutrophil activity with approximately 50% inhibition of bglu activity in gcf was observed. periodontal health was also restored and maintained during posttreatment evaluations. in another study, bglu activity was posited as a better biomarker compared to alkaline phosphatase for evaluating the response to non-surgical periodontal therapy in patients with different stages of periodontal disease [73] . taken together, these results articulate the potentials of bglu activity as an indication of pd, tissue inflammation or destruction as well as a biomarker of neutrophil influx, disease risk, susceptibility, status, or severity for timely diagnosis of the inflammatory disorder. however, administration of doxycycline hyclate in 16 subjects with aggressive periodontitis was inefficient on salivary bglu activity [74] . surprisingly, an increase in enzyme activity was found even after 2 months of treatment in 12 patients and a decrease in 4. although, the authors concluded bglu concentration only facilitated the detection of periodontal inflammation and not worthy as biomarker of susceptibility, their contrasting result is linkable to periodontal pretreatment of subjects prior to examination and short treatment time using doxycycline. empirical evidence affirms the role of inflammatory mediators and signalling pathways in the pathogenesis of insulin resistance and b-cell dysfunction in diabetes mellitus [75e77]. in parallel, these inflammatory mediators e.g. cytokines and mmps are also produced in periodontal tissues [78e82]; hence, leading to compromised glycaemic control after accessing systemic circulation. the susceptibility to periodontitis is therefore heightened in persons with diabetes or a history of the hormonal imbalance and vice versa. putatively, an effective therapy for one affords an improved management of the other [83e85]. accordingly, bglu activity was found to be significantly elevated in the saliva of patients with chronic periodontitis and diabetes compared to nondiabetic ones [86] . a significant correlation to bglu activity was observed for pd and cal and not gg-i in nondiabetic subjects with periodontitis; whereas, these periodontal parameters were similar in diabetics. the increased disease burden was also established when bglu activity was measured in the sera of patients with both diabetes and periodontitis [87] . compared to controls, enzyme activity was 9-fold higher in diabetic subjects with periodontitis and only 2-fold higher in diabetic subjects without periodontitis. this difference was attributed to damaged lysosomal membrane and consequent enzyme leakage into the cytosol. the quantification of bglu activity in neutrophil leukocytes exposed to bacteria stimuli has shown that diabetic patients with chronic periodontitis have strikingly higher enzyme activity compared to nondiabetics burdened with periodontitis and healthy subjects [88] . using discriminant analysis, the study established that bglu activity has a diagnostic potential with great accuracy in distinguishing healthy subjects from diseased ones. bglu activity stimulated by nonopsonized staphylococcus aureus showed strongest correlation with the intensity of periodontal parameters compared to opsonized zymosan and prodigiosan, while the highest enzyme activity was stimulated by opsonized prodigiosan. the strength of association between salivary bglu activity, periodontitis and type 2 diabetes mellitus has been examined in dentate patients with different stages of periodontal disease, diabetic patients and edentulous patients [89] . in all subjects, diabetic status contributed significantly to bglu activity, while periodontal status had greater influence on enzyme activity. higher enzyme activity was also found in nondiabetic dentate patients with periodontitis compared to edentulous controls. overall, compared to il-1b, bglu activity level was more reliable as biomarker of disease severity for periodontitis than it was for the presence of diabetes. in a predating study [90] , gcf bglu activity also correlated strongly with pd, cal and bop regardless of diabetic status. lower enzyme activity was seen in diabetic subjects compared to those with periodontitis. the results suggested a lower release of bglu in response to systemic inflammation (diabetes) due to reduced deficiency in neutrophil activity, in contrast to amplified activity in response to local inflammation (periodontitis). despite landmark developments in oncology, the high rates of morbidity and mortality and increased medical costs associated with all forms of cancer coupled with patients' psychological trauma on disease diagnosis has remained a major threat to global public health. the successful disease management and sustained wellbeing of affected individuals is however subject to early disease diagnosis and constant evaluation of administered therapy. this in turn relies on efficient tumour markers to ascertain disease risk or status i.e. early stage or metastatic cancer [91] . although a vast number of biomarkers have been identified for cancer diagnosis, only few have gained clinical approval due to inconsistencies and false positives in their utility [92] . a successful biomarker is that which will not only be specific and selective but will also predict treatment response, while differentiating lethargic and aggressive tumours. the aetiology of cancer is known to be closely associated with inflammatory pathways and oxidative stress, which jointly create microenvironments favouring neoplasia [93, 94] . hence, in the tumour milieu, an increase in extracellular activity of lysosomal exoglycosidases responsible for the catalytic degradation of glycoconjugates occur, due to malignancy-mediated cell-death and/or lysosomal damage. in this vein, available practical data supports the overexpression of bglu in extracellular fluids and tissues around tumour sites as a prime factor in cancer aetiology [24] ; thus, suggesting the enzyme's viability as cancer biomarker [95] . for example, bglu activity was 2-folds higher in the blood samples of 21 patients with colorectal adenocarcinoma compared to healthy controls [96] . based on cell maturity and clinical grading, enzyme activity was highest in subjects with low or moderately differentiated cells and in subjects with tumours infiltrating surrounding tissues and organs or visceral peritoneum respectively. estimation of serum bglu activity in this case proved to be 80% sensitive and 82% specific in distinguishing diseased and healthy subjects. likewise, enzyme activity was elevated by 6-fold in the peritoneal fluids of patients with ovarian or endometrial cancer compared to women with infertility used as controls [97] . the stronger correlation between cancer stage and bglu activity, b-galactosidase and a-mannosidase, reiterated the improved clinical viability of bglu activity as biomarker of gynaecologic tumour status and severity. however, bglu activity was equally elevated in the peritoneal fluid of patients with pelvic inflammation hence compromising its application for differential diagnosis of gynaecologic cancer and pelvic inflammatory disease. bacterial peritonitis is a life-threatening inflammation of the peritoneum e the tissues lining of the inner abdominal walls. as with other inflammatory conditions, cellular damage and polymorphonuclear leukocytes activity increases the level of lysosomal enzymes in the extracellular space via enzyme leakage through the cellular membrane. thus, quantification of these enzymes provides a potential diagnostic platform. in fact, bglu activity in the peritoneal fluid of patients with culture positive bacterial peritonitis was 9 and 33-fold greater compared to that of patients with acute mesenteric lymphadenitis and controls respectively [98] . peritoneal fluid-bglu activity measurement in this case holds greater clinical potential compared to b-galactosidase and a-mannosidase for early disease diagnosis and evaluating patient's response to treatment. similarly, considering the current global prevalence of antimicrobial resistance, timely diagnosis of bacteria-mediated meningeal inflammation (bacterial meningitis) is crucial to the outcome of therapeutic intervention. it has been shown that bglu activity is elevated in cell-free cerebrospinal fluid (csf) of bacterial meningitis patients early in the disease pathogenesis, even when traditional laboratory parameters such as number of csf cells, csf-blood glucose ratio and protein concentration indicated normal status [99] . csf-bglu as biomarker was superior to these traditional parameters for early and sensitive prediction of patient's response to antibiotic treatment. csf-bglu activity in neonates and infants has also been studied as biomarker for differential diagnosis of sterile csf pleocytosis due to urinary tract infection (uti) or meningitis [100] . median bglu activity in csf of patients showed significant difference without overlapping in each disease state i.e., bacterial meningitis (168), viral meningitis (26.5) and uti with sterile csf pleocytosis (44.1); median enzyme activity was lowest (19.1) in febrile subjects without csf pleocytosis used as controls. this proffers an unambiguous diagnosis of each condition with 100% sensitivity and specificity. in contrast, broad overlapping was found with classic csf laboratory parameters viz., csf cell number, neutrophil number, protein concentration and csf-blood glucose ratio. recently, a case-control study concluded that bglu activity in bronchoalveolar lavage fluid (balf) is clinically useful as biomarker of bacterial lung infection [101] . in balf samples from 92 children, enzyme activity was significantly higher in patients with positive balf bacterial culture (cþ) compared to those with culture negative balf (ce). 43 nmol 4-methylumbelliferone (4mu)/ml/h was identified as optimum activity value, which allowed differential sample screening (i.e. cþ from ce) with 84.8% sensitivity and 78.3% specificity. moreover, receiver operating characteristics (roc) curve analysis established the superiority and higher prognostic value of bglu activity for bacterial lung infection compared to % polymorphonuclear cell count, human leukocyte elastase, il-8 and tnfa. repeated exposure to organophosphorus compounds (op) in pesticides is responsible for the lethal poisonings seen in agricultural and veterinary workers; particularly, those in developing countries. op exerts their fatal effects by inhibiting acetylcholinesterase (ache) in nervous tissues, leading to muscarinic and nicotinic effects with central nervous disturbance [102] . on the other hand, bglu is retained in liver microsomal endoplasmic reticulum by forming non-covalent binding complexes with its accessory 64 kda glycoprotein, egasyn, a carboxylesterase isozyme [103, 104] . liver intake of op however cleaves microsomal bgluegasyn complex thus elevating the level of bglu in plasma to consequently making it an alternative biomarker for op pesticide poisoning diagnosis [105e107]. a cross-sectional study of pest control workers [108] and plastic greenhouse workers [109] , established that plasma bglu activity was more sensitive as biomarker of op poisoning compared to butyrylcholinesterase (buche) and acid phosphatase (acp). the enzyme's activity was higher in subjects with increased exposure than those with low exposure and controls. bglu activity correlated significantly with buche and acp activities. likewise, in a case-control study, serum bglu activity was significantly increased in patients with severe poisoning compared to mildly affected patients and controls [110] . the difference in enzyme activity between the latter groups was insignificant. nonetheless, mildly exposed subjects have been reported to show elevated bglu activity than severely exposed and control subjects, which suggests the enzyme's utility for diagnosing lowlevels of op exposure. for instance, a study [111] , observed the order of serum bglu activity based on poisoning severity as mild > severe > moderate poisoning, while the order after 12 and 24 h of admission was mild > severe z moderate poisoning; strong correlation also persisted between serum bglu and buche activities. similar results were also obtained in a recent cross-sectional study [112] . therein, moderately exposed subjects showed higher enzyme activity than the highly exposed, while non-significant statistical difference persisted between control and highly exposed groups. notably, bglu activity correlated well with diabetes propensity, lipid profile, liver function and buche but not ache. in another cross-sectional study, significant difference in plasma bglu activity only exists between controls and subjects with chronic exposure (1e45 years) to op [113] . activity level was similar in controls and patients with acute poisoning; although 3 out of the 5 examined acutely poisoned patients showed increased level of plasma bglu activity. however, a case report of an acute op self-poisoned patient reached contrasting conclusion [114] . the opposing result can be linked to sample size and limited data on patient's medical history. moreover, the reduced susceptibility of bglu-egasyn complex to op in humans is another primal factor [115] . in contrast to murine bglu-egasyn interaction, binding in humans is independent of the c-terminal 18 amino acids propeptide in bglu and esterase active site of egasyn. rather, it involves the 51 amino residues in bglu internal segment i.e. residues 228 to 279. the progress and momentous achievements in drug discovery cannot be isolated from the wealth of chemical entities i.e. natural products, gifted to man by nature. many successful molecular candidates of pharmaceutical drug discovery programmes are indebted to the presence of natural product-derived/inspired fragments in their scaffolds [116] . therefore, the chemical space of natural products (both plants and microbes) has continued to be a much-researched depository for therapeutically significant molecules. in this section, we review some application of natural products including isolated compounds, whole plant extracts and natural product-inspired molecules as potent inhibitors of bglu. the structures of selected inhibitors (ic 50 5 mm) are presented in table 2 at the end of the section. the clarification [117, 118] that d-saccharic acid-1,4-lactone (5, fig. 3 ) (saccharolactone or d-glucaric acid-1,4-lactone) is the active and non-toxic bglu inhibitor responsible for the strong inhibitory potency found with saccharate solutions has precipitated an increased interest in the compound. despite the poor stability at physiological ph, d-saccharic acid-1,4-lactone (d-sal) has been explored extensively for its therapeutic significance. although an ic 50 value of 3.6 mm was reported in the pioneering work [117] , a value ca. 40 mm is recurrent in literature. nevertheless, at a concentration of 1 mm, d-sal completely inhibited the hydrolytic action of human liver-derived bglu on quercetin glucuronides [119] , while over 90% inhibition of bglu in breast milk was recorded at 10 mm [120] . also, using urine samples of male sprague-dawley rats, d-sal was identified via metabolomics strategy as one of the therapeutic constituents in liuweidihuang pills, a famous traditional chinese prescription for cancer treatment and prevention [121] . whereas, in a 6-days cumulative study, intraperitoneal pre or cotreatment of female wistar rats with 3 mg/ml, 10 mg/ml or 10 mg/0.5 ml d-sal reduced the severity of cpt-11 induced smallintestine mucosal damage assessed by the number of apoptotic cells or mitotic figures, compared to cpt-11 treated controls [122] . damage reduction was independent of treatment schedule. the synthetic and natural precursors of d-sal i.e., 2,5-di-oacetyl-d-glucaro-1,4:6,3-dilactone (d-sdl, 6, fig. 3 ) and d-glucurono-g-lactone (d-gl, 7) respectively, have also potently inhibited bglu activity in male fischer rats thereby providing chemopreventive effects against azoxymethane-induced colon carcinogenesis [123] . diet supplementation with 0.5 or 2% d-sdl for 5 weeks significantly reduced aberrant crypt foci formation (i.e. preneoplastic lesions) by over 48.6 and 55.3% respectively, compared table 2 most active natural product-derived bglu inhibitors with ic 50 to azoxymethane-controls. d-gl did not afford any significant reduction in colonic tumour incidence during this initiation phase. in addition, 32 weeks treatment with d-sdl or high dose (2%) of d-gl, after 3-weeks subcutaneous injections of 15 mg/kg azoxymethane, provided over 70% inhibition of colon carcinogenesis during the post-initiation phase. it was suggested that d-sdl is a blocking agent which may inhibit pre-neoplasia during the initiation phase, while d-gl is only active during post-initiation of colon carcinogenesis. the increased hydrolytic stability of d-sdl to d-sal in vivo might also be responsible for these observed phenomena [124] . in another study, d-sal was more therapeutically efficient compared to its natural precursor (d-gl), for reducing epidermal hyperplasia (lethargic tumour promoter) and inflammation in 7,12dimethylbenz(a)anthracene (dmba)-induced complete skin carcinogenesis of sencar mice [125] . pre and cotreatment of murine models with d-sal for 4-weeks (twice weekly) by topical administration (0.5e4 mg) or dietary treatment (0.5 and 1%), both significantly reduced epidermal hyperplasia and inflammation by up to 57% of dmba-controls in a dose-dependent manner. d-sal also inhibited the initiation of carcinogenesis by reducing dmbainduced oxidative dna damage (c-8 hydroxylation of guanine) and mutations in codon 61 of ha-ras gene, by up to 78%. in contrast, d-gl only inhibited epidermal hyperplasia with topical treatment and inflammation by dietary treatment (5% in diet); albeit with inferior potency compared to d-sal. interestingly, another lactone-based bglu inhibitor (8, fig. 3 ), exhibited 8-fold superior potency compared to d-sal [126] . isolated from the ethyl acetate extracts of aspergillus terreus, an endophytic fungus initially isolated from marine alga laurencia ceylanica, butyrolactone (8) with ic 50 ¼ 6.2 mm possesses 16-fold stronger potency than its prenylated isomer (9) . bglu in breast milk is believed to be involved in neonatal jaundice and hyperbilirubinemia, by increasing serum bilirubin levels via enterohepatic bilirubin circulation in breastfed newborns, in contrast to those fed with infant formulas [47] . therefore, the suppression of bglu-mediated deglucuronidation has been proffered as a practicable regimen. l-aspartic acid (10, fig. 3 ) in casein hydrolysate formulas was identified as the active bglu inhibitor responsible for the lower levels of neonatal jaundice observed in newborns receiving such formulae [127] . at 100 mm, the natural amino acid showed~86% inhibition of bglu that is, 100-fold more potent than d-isomer. moreover, in a randomized and double-blind clinical trial involving 64-newborns, supplementing breastfeeding in the first week of life with 6 doses of l-aspartic acid (180 mg/5 ml of water/day) was more potent against bglu activity than higher concentrations of enzymatically hydrolysed casein (infant formula containing the inhibitor) or whey/casein (routine formula lacking the inhibitor) [128] . l-aspartic acid supplementation at minimal aliquot concentration significantly lowered transcutaneous bilirubin levels (25% lower than control), leading to higher faecal bilirubin excretion and reducing neonatal jaundice, with no adverse effects. flavonoids are evidently an indispensable class of natural products due to their ubiquity in the vegetal domain and their therapeutic significance. found in a variety of plant parts (leaves, flowers, stems, nuts, seeds etc.), they perform important functions especially plant's growth and protection against pathogenic invasion. this intrinsic property encourages their utility as a major constituent of different local medicinal formulations and diets, while their acceptable toxicity profile and physiologic tolerance further presents them as druggable subjects. flavonoids are typified by the c6ec3ec6 ring system that is, their basic structural skeleton consists of two benzene rings (a and b) linked by heterocyclic pyran ring c (fig. 4) . variations on the chromane core (ring a and c) and attachment position of ring b due to biosynthetic origins lead to classification into flavones, flavanols, flavanones, flavonols, isoflavones, neoflavonoids, anthocyanins and chalcones [129] . this ring system and the presence of hydroxyl units has availed flavonoids with different pharmacological properties such as antidiabetic, antioxidant, antimicrobial, antiplasmodial, antiproliferative and particularly enzyme inhibition [130, 131] . luteolin (11, fig. 4 ), a dietary 3 0 , 4', 5, 7-tetrahydroxyflavone has been reported as a viable chemopreventive and anticarcinogenic agent plausibly by inhibiting bacterial bglu-mediated enterohepatic circulation of colonic carcinogens [132] . the 30-weeks cumulative study using male wister rats showed that pre or cotreatment with luteolin by intragastric gavage per os (p.o.) at 0.1, 0.2 or 0.3 mg/kg body weight/day, significantly reduced bacterial bglu activity thereby suppressing 1,2-dimethylhydrazine (dmh)induced colon adenocarcinomas in a dose-dependent manner compared to dmh-controls. although 0.2 and 0.3 mg kg à1 day à1 produced similar result. luteolin supplementation also reduced tumour size from 2 cm to 0.25 and 0.50 cm during the initiation and post-initiation stages respectively, as well up to 90% reduction in tumour incidence. in addition, luteolin (11), its 7-o-glycoside (12), apigenin-7-o-glycoside (13) and catechin (14) were identified as key constituents in the leaf extracts of pistacia terebinthus responsible for the high e. coli bglu inhibitory potency [133] . at the highest test concentration (8.2 mg/ml), the leaf extracts exhibited 97.2% inhibition of bglu activity, corresponding to an ic 50 value of 2.11 mg/ml. in another exploit, 32 natural flavonoids were evaluated for their inhibitory strengths against e. coli bglu [134] . it was established that luteolin (11) , similar flavones e baicalein (15), scutellarein (16) and its glucuronidated analogue scutellarin (17) , as well as dietary and ubiquitously occurring flavonol e quercetin (18) , are superior inhibitors (ic 50 ¼ 5.76e29.64 mm) compared to reference inhibitor d-sal (ic 50 ¼ 36.07 mm); isoflavones and dihydroflavones displayed weaker inhibition. overall, luteolin (11) and scutellarein (16) emerged the most potent flavone-based e. coli bglu inhibitors with ic 50 ¼ 8.68 and 5.76 mm respectively. sar analysis (fig. 4 ) revealed the importance of 5,6,7-trihydroxy (pyrogallol) unit to bacterial bglu inhibition, as unsubstitution or replacement of a hydroxy unit with methoxy or glycosyl unit led to significant loss of inhibitory activity. o-methylation at positions-6, 7 and 4 0 and installing oh unit at position-3 was also detrimental to potency, whereas the presence of hydroxy unit at c-4' favoured potency. in addition, molecular docking studies of luteolin and scutellarein in the active site of e. coli bglu showed hydrogen bonding (h-b) interactions of phenolic oh units at c-5 and c-7 with catalytic acid glu413 and arg562 as well as hydrophobic contacts with ser360 and leu361 in the bacterial loop. furthermore, subjecting the methanolic extracts of edible flower and pedicel of aquatic rhizomatous herb e nymphaea pubescens (water lily) to bioactivity-guided fractionation established the superior (3-fold) bacterial bglu inhibitory potency of crude flower extracts compared to pedicel extracts and silymarin e a marketed natural bglu inhibitor [135] . kaempferol (19) was subsequently identified as one of the active metabolites with promising activity; ic 50 ¼ 36.47 mm and 76-fold superior to silymarin. interestingly, the lower activity of kaempferol (19) compared to flavonoids (11, 15e18) affirmed the sar results described earlier. amidst 21 constituents found in commonly used chinese herbal medicines, two prenylflavonoids, sanggenon c (20, fig. 5 ) and kuwanon g (21) emerged as the most potent broad-spectrum inhibitors (>70% inhibition; ic 50 ¼ 12.5 and 7.4 mm respectively) of whole human gut bacterial bglu (consisting of eight bacterial isolates), compared to reference compound amoxapine (7.3% inhibition) [136] . compound 20 exhibited improved potency against recombinant bglu from e. coli (ecogus) and s. pasteuri (spasgus), ic 50 ¼ 0.40 and 0.33 mm respectively, compared to compound 21 (ic 50 ¼ 1.6 and 0.98 mm respectively). however, compound 21 was a stronger inhibitor of bglu from three representative bacterial isolates (e. coli, e. fergusonni and s. pasteuri) compared to compound 20. additionally, molecular docking studies of 20 and 21 in the binding pockets of ecogus and spasgus revealed both flavonoids bind (via their hydroxy groups) in the allosteric site and not the active site of the recombinant enzymes. the higher number of h-b interactions formed by compound 21 supported the overall increased potency compared to compound 20. the realization that pro-inflammatory mediators such as bglu, released from degranulated mast cells or neutrophils, play significant roles in inflammatory disorders has sparked increased interest in the search for potent inhibitors of such processes as antiinflammatory drug candidates. in this regard, dihydroxychalcones 22 and 23 (fig. 6 ) isolated from the roots of hypericum geminiflorum holds therapeutic promise [137] . compounds 22 and 23 potently inhibited the release of bglu from degranulated rat neutrophils with ic 50 values of 5.80 and 6.60 mm respectively, better than the reference inhibitor trifluoperazine. however, only compound 23 showed moderate activity against the enzyme's release from degranulated rat peritoneal mast cells with ic 50 ¼ 70.0 mm. conversely, an isomer of luteolin e norartocarpetin 24 (fig. 6) and flavonoid-like mornigrol d 25 (fig. 6) , both isolated from the barks of morus nigra (black mulberry), were moderately potent bglu inhibitors [138] . at 100 mm, compounds 24 and 25 showed 67.7% and 65.9% inhibition respectively against the release of bglu from activated rat neutrophils. however, chiral flavonoid alkaloids isolated from the ethanolic extracts of scutellaria moniliorrhiza and subsequently separated using chiral hplc, e scumonilines 26e29 (fig. 6) , are better drug candidates compared to compounds 24 and 25, but similar to compounds 22 and 23 [139] . scumonilines 26e29 displayed~63% inhibition at 10 mm against bglu release from activated rat neutrophils with ic 50 values of 5.21, 5.85, 5.47 and 5.16 mm respectively; better than reference inhibitor ginkgolide b (ic 50 ¼ 6.63 mm). compounds 26e29 were also more potent lead molecules compared to both glucuronate esters 30e34 (fig. 6 ) isolated from similar scutellaria regeliana [140] and chiral egeninebased alkaloids 35e37 isolated from the rhizomes of corydalis decumbens [141] . compounds 30e34 showed 43.7e47.1% inhibition at 10 mm, whereas compounds 35e37 were more inferior inhibitors at the same concentration with 32.4e41.3% inhibition. evidently due to its phycocyanin-rich content and potent reduction of zymosan-induced damage to knee joint histological architecture, edible blue-green microalgae e spirulina is deemed a therapeutically viable anti-arthritic agent [142] . an analysis of the synovial fluid of female of1 mice knee joints after 4-days intraarticular injection of zymosan, followed by 8-days oral administration of spirulina water-suspension at 100 mg/kg and 400 mg/kg, showed 78.7% and 89.2% inhibition of bglu activity respectively. subsequently, arthritic parameters such as tibial articular cartilage destruction, erosion of bone structure, articular tissue inflammation, loss of general joint architecture and pannus formation, were all markedly reduced in spirulina fed mice compared to those receiving zymosan only. these anti-inflammatory and anti-arthritic effects were comparable to reference drug triamcinolone, a tuber extracts of arisaema tortuosum (whipcord cobra lily) has shown moderate anti-inflammatory effect via bglu inhibition in a dose-dependent manner [143] . conceivably, the presence of quercetin, rutin and lectin, identified through chromatographic profiling, facilitated maximum inhibition of 92.9% at 100 mg/ml, superior to reference inhibitor salicylic acid. employing a similar approach with ginger rhizomes [144] , only 6-gingerol (38, fig. 7) was identified with 85% inhibition of bglu at 1 mm, comparable to salicylic acid (82% inhibition). it is also noteworthy that constituents profiling of essential oils extracted from the leaves of seven local varieties of piper betle l. identified eugenol (39) with an ic 50 value of 616.68 mg/ml similar to 794.62 mg/ml of silymarin; although the essential oils were only moderate bglu inhibitors with ic 50 ! 5.26 mg/ml [145] . however, metabolomics profiling of the leafy shoots-methanolic extracts of three swertia species viz. s. chirayita, s. decussata and s. bimaculate, presented s. chirayita as the strongest inhibitor of bglu and xanthones as the most active metabolites responsible for the swertia species' potency [146] . the c-2-glycoside of norathyriol, mangiferin (40) emerged as the most active and therapeutically promising xanthone with ic 50 ¼ 38 mm and 50-fold more potent than silymarin. shikunshito-kamiho (sktk), a traditional oriental formulation and fenugreek seeds (fgs), an indian spice, are natural ethnotherapeutic agents with potentials identical to luteolin (11) i.e., attenuation of colon carcinogenesis via potent inhibition of bacterial bglu activity [147, 148] . 5-weeks oral administration of spf male icr mice's diet supplemented with 20 mg/kg or 60 mg/kg sktk water extracts, after 10 weeks subcutaneous injection of dmh (weekly), equipotently reduced bglu activity during and after treatment by 14.9% and 21.3% of controls (dmh alone) respectively. tumour incidence in colon, measured by the number of aberrant crypt foci was also significantly reduced from 21.6 (distributed in sigmoid and descending colons) in controls, to 6.9 and 6.4 (distributed in rectum) at 20 mg/kg and 60 mg/kg doses respectively. similarly, diet supplementation with fgs significantly reduced intestinal bglu activity, leading to a marked reduction in tumour incidence from 93.3% in male wister rats receiving dmh alone for 15 weeks to 16.6% in rats receiving dmh þ 2 g/kg fgs water extracts for 30-weeks cumulative period. flavonoid, saponin and fibre rich content of fgs were presumed to be responsible for its anticarcinogenic activity. the hepatoprotective activity of chinese medicinal formulation e reduohanxiao-tang, used in the treatment of stroke and liver diseases has also been attributed to its ability to inhibit bacterial bglu activity in vivo [149] . water extracts of this local formulation and two of its ingredients viz. rhizomes of pueraria thunbergiana and scutellaria baicalensis potently inhibited the activities of e. coli and rat liver-derived bglu with ic 50 values ranging from 0.35 to 1.42 mg/ml. subsequently, oral administration of these extracts at 100 mg/kg alleviated ccl 4 -induced liver injury measured by significant reduction in serum aspartate aminotransferase (ast), alanine aminotransferase (alt), and lactic acid dehydrogenase (ldh) levels, compared to controls. the superior hepatoprotective effect of pueraria thunbergiana was accredited to isoflavone daidzein (41, fig. 7) , an aglycone metabolite of main components puerarin and daidzin by intestinal bacteria. daidzein inhibited e. coli and rat liver bglu with ic 50 ¼ 0.41 and 0.50 mg/ml respectively whereas puerarin and daidzin were inactive. fascinatingly, structurally similar tectorigenin (42), an aglycone metabolite of 7-o-glycoside e tectoridin (43), isolated from the flowers of pueraria thunbergiana, exhibited better inhibitory potency (ic 50 ¼ 0.30 mg/ml) than its congeners [150] . 50 mg/kg intraperitoneal pre-treatment of male icr mice with tectorigenin or 100 mg/kg oral administration of tectoridin provided better hepatoprotection than dimethyl diphenyl bicarboxylate (ddb) and daidzein, by significantly lowering serum ast, alt and ldh levels relative to ccl 4 -treated controls. the prodrug behaviour of tectoridin, identical to puerarin and daidzin above, was also established by its absence in the serum after 250 mg/kg oral administration (only tectorigenin was detected) and its failure to provide desired hepatoprotection after 100 mg/kg intraperitoneal administration. the triterpenoid 18b-glycyrrhetinic acid (44, fig. 8 ) also known as enoxolone, is the aglycone metabolite by human intestinal bacteria responsible for the hepatoprotective activity exhibited by saponin e glycyrrhizinic acid 45 [151] . glycyrrhizinic acid (45) is isolated from the rhizomes of glycyrrhiza uralensis e the sweetening agent in sktk. it exists as a natural glucuronide conjugate of 18b-glycyrrhetinic acid (44) hence making it (45) a substrate for bglu-mediated hydrolysis for consequent release of active inhibitor 44. in vitro evaluation against e. coli and rat liver bglu revealed stronger potency of glycyrrhizinic acid (ic 50 ¼ 12.15 and 97.21 mm respectively) compared to 18b-glycyrrhetinic acid (ic 50 ¼ 509.90 fig. 7 . natural bglu inhibitors profiled from plant extracts and ethnomedicinal preparations. and 42.49 mm respectively). moreover, at 100 mg/kg doses, oral treatment with glycyrrhizinic acid or intraperitoneal treatment with 18b-glycyrrhetinic acid, protected the hepatocytes of male wistar rats against ccl 4 -induced liver injury evident by the significant reduction in ast, alt and ldh levels compared to ccl 4controls. intraperitoneal administration of glycyrrhizinic acid also did not provide hepatoprotection akin to tectoridin (43) . in addition, structurally similar emodinol (46) , isolated from the roots of perennial herb paeonia emodi showed stronger e. coli bglu inhibition in vitro with ic 50 ¼ 63 mm compared to 18b-glycyrrhetinic acid [152] . microbial biotransformation of drugs and/or their precursors to new molecules with modulated pharmacological profile is considered an invaluable tool in drug design and development [153] . the natural product class e steroids, are key substrates in this regard [154] . accordingly, naturally occurring androstane steroid hormone, 5-dehydroepiandrosterone (47, fig. 8 ) and its macrophomina phaseolina metabolites were examined for their bglu inhibitory potentials [155] . the inferior potency/inactivity of metabolites compared to parent 5-dehydroepiandrosterone (ic 50 ¼ 77.9 mm) suggests that having an alkene unit at position-5 and cyclopentanone unit in the molecular architecture is crucial to inhibitory potency. conversely, the synthetic anabolic steroid, dianabol and its metabolites by filamentous fungus cunninghamella elegans or macrophomina phaseolina were inactive against bglu; except metabolite (48) with ic 50 ¼ 60.7 mm [156] . the e-oxime derivative (49) of an inactive metabolite however showed decent inhibitory potency with ic 50 ¼ 49.0 mm, equipotent with d-sal and 2-fold superior than its z-isomer. nonetheless, the therapeutic safety of these dianabol derived bglu inhibitors is questionable considering the increased risk of hepatotoxicity associated with oral administration of 17a-alkylated anabolic steroids [157, 158] . the fascinating ability of prebiotics and probiotics to positively influence the composition and behaviour of human intestinal microbiota, has been continuously explored with considerable success to improve human health [159e161]. precisely, lactic acid bacteria (lab) probiotics can selectively utilize non-digestible oligosaccharide prebiotics as carbon source to produce active metabolites, which modulates or stimulates the activities of certain intestinal bacteria hence, eliciting important physiological response and conferring health benefit [162] . consequently, lab e lactobacillus acidophilus csg afforded stronger inhibition of intestinal bacteria (including e. coli) producing bglu thus providing hepatoprotection to male icr mice, compared to lactobacillus brevis hy7401 and bifidobacterium iongum hy8001 [163] . when anaerobically cocultured with e. coli (hgu-3), l. acidophilus csg also potently inhibited bglu productivity of e. coli compared to other labs. as a result, oral treatment of the murine models with 500 mg/kg of l. acidophilus csg alleviated ccl 4 -induced hepatotoxicity by lowering ast and alt levels to 66% and 57% respectively, of ccl 4 control group. whereas, for t-bhpinduced hepatotoxicity, ast and alt levels were lowered to 62% and 48% respectively, better than reference hepatoprotective agent ddb. similarly, lactobacillus plantarum cfr 2194 was the most effective strain of lactobacilli metabolizing fructooligosaccharide prebiotics to short chain fatty acids, thereby altering bglu productivity of e. coli [164] . lactic acid (50, fig. 9 ) and especially nbutyric acid (51) were identified as the major short chain fatty acid metabolites in the culture filtrate of lactobacillus plantarum cfr 2194 and fructooligosaccharides responsible for the observed decrease in bglu activity. the most abundant and relatively stable thiosulfinate, s-methyl methanethiosulfinate (52, fig. 9 ), found in chinese chive (allium tuberosum rottier), has exhibited strong inhibitory potency (ic 50 ¼ 3.60 mm) against e. coli bglu [165] . compared to other disulphides viz., dimethyl, allyl methyl, and diallyl disulphides, compound 52 is more useful for alleviating drug induced toxicities or providing hepatoprotection. in parallel, a naturally occurring acetal isolated from red macroalga neodilsea yendoana, isogloiosiphone b (53), possesses similar potential, although with weaker potency (ic 50 ¼ 57.0 mm) compared to compound 52 [166] . the adverse role of inflammatory pathways and corresponding mediators including lysosomal enzymes during the pathogenesis of myocardial infarction again implicates bglu in the cardiovascular disease. in a study which examined the protective effects of thymol (54, fig. 9 ) on inflammation in isoproterenol-induced myocardial infarction using male albino wistar rats [167] , the therapeutic benefit of inhibiting the release of bglu, other lysosomal enzymes and pro-inflammatory cytokines was evident in the restoration of near-normal myocardial histology and function, compared to diseased controls. rats pre and cotreated with thymol by intragastric gavage at 7.5 mg/kg body weight/day for 7 days and subcutaneous injection of 100 mg/kg isoproterenol for 2 days (day 6 and 7), showed significantly reduced levels of cardiac troponin-t (a cardiotoxicity biomarker) and high-sensitive c-reactive protein in their sera, compared to those treated with isoproterenol only. most importantly, the activities of lysosomal enzymes i.e. bglu, bgalactosidase, cathepsin b and d in serum and heart were also potently inhibited to near-normal. these anti-inflammatory effects of thymol afforded a well-protected myocardium with stable histological architecture. polyhydroxylated piperidine and pyrrolidine alkaloids commonly referred to as iminosugars (fig. 10a) , are a noble class of sugar mimics in which the pyrano or furano endocyclic oxygen has been replaced with a basic nitrogen atom [168] . this class also include isoiminosugars (i.e. 1-azacarbasugars or 1-n-iminosugars) having a methylene unit in place of endocyclic oxygen and the anomeric carbon replaced with nitrogen. although these ring alterations render iminosugars metabolically inert, their protonated forms mimic the pyranosyl or furanosyl unit in gh substrates, especially the putative oxocarbenium ion-like transition state (2, fig. 2 ) in gh catalysed hydrolysis [21, 169] . this in turn facilitates their recognizability by ghs and other carbohydrate-recognizing proteins for corresponding enzyme inhibition. since the isolation of nojirimycin (55, first iminosugar) and siastatin b (56, first isoiminosugar) from streptomyces cultures in 1966 and 1974 respectively [170, 171] , these sugar mimics have been a recurring subject of intensive research owing to their extensive biological activities and therapeutic applications elicited majorly through potent inhibition of ghs [172] . the strongest iminosugar-based inhibitors of bovine liver-derived bglu reported so far (fig. 10b) , with promising antitumor potentials are siastatin b derivatives 57, 58 and 59 with ic 50 ¼ 65, 62 and 68 nm respectively [173] . therefore, this section reviews iminosugars and their analogues as natural productinspired bglu inhibitors, without undue repetitions of other monographs [4, 21, 168, 169] covering them. uronic analogues of nojirimycin bearing glycaro-1,5-lactams or the bicyclic analogues with imidazole and tetrazole units (i.e. tetrahydrotetrazolopyridine-5-carboxylates and imidazopyridine-5carboxylates respectively), were prepared to examine the effect of sugar-acid configuration and presence of lactam, tetrazole or imidazole moieties on inhibitory potency against bovine liver bglu [174, 175] . evidenced by the most potent inhibitor 60 ( fig. 11 ) with k i ¼ 12 nm, gluco-configured units, are stronger bglu inhibitors compared to galacto-and manno-analogues, due to their better mimicry of glucuronic acid (4). the imidazole ring also conferred stronger inhibitory potency than tetrazole or lactam units whereas glycarolactams and tetrazoles shared similar potencies; except galacto-tetrazole (64) with~200-fold inferior potency to galactolactam (62) . further, although sugar configuration at c-4 was found to be ineffective on bglu inhibition for glycaro-1,5-lactams 61 and 62, it was very significant for tetrazole and imidazole derivatives. gluco-tetrazole (63) was 300-fold better than galacto-tetrazole (64), while gluco-imidazole (60) was 600-fold more potent than galacto-imidazole (65) and 1200 superior to manno-imidazopyridine (66) , which differs at c-2. moreover, sugar configuration of acid moiety at c-5 also had significant influence on potency. lconfigured units 67, 68 and 69 were 20-50-fold weaker than their d-isomers 63, 62 and 61 respectively. more importantly, the 2-fold increased potency of gluco-imidazole (60) compared to gluco-tetrazole (63) was attributed to stronger interaction of gluco-imidazole (60) with catalytic nucleophile glu540 compared to glucotetrazole (63) . interaction with catalytic acid glu451 was compromised due to protonation of the imidazole ring in the zwitterionic form. conversely, similar bicyclic molecules of nojirimycin with cyclic carbamate, urea or guanidine pharmacophores are weaker bglu inhibitors [176] . in all, only cyclic carbamates 70e73 (fig. 12) showed moderate inhibitory activity against bovine liver bglu. cyclic carbamates with carboxylic acid unit at c-5 of nojirimycin ring were also better inhibitors than their hydroxymethyl analogues. thus, compounds 71 and 73 were the most potent overall with ic 50 ¼ 218 and 259 mm respectively. it is noteworthy that bicyclic indolizidine iminosugar 74, with hydroxymethyl unit is also a weak inhibitor (<50% inhibition at 1 mm), although it exhibits desirable selectivity (7-fold) for e. coli bglu [177] . surprisingly, carbasugar 75 shared a similar fate with ic 50 ¼ 170 mm against e. coli bglu, even though it is not an iminosugar [178] . taken together, these results partly suggest that ability to mimic d-glucuronic acid favours bglu inhibitory activity. accordingly, glucuronic acid analogue of naturally occurring hemiaminal calystegine b 2 (76, fig. 13 ), uronic-noeurostegine (77) , was synthesized in 27-steps from levoglucosan [179] . compound conferred with improved selectivity for e. coli bglu. this is partly due to their improved lipophilic balance for bacterial cell penetration afforded by their c-alkyl unit and improved chemical stability of cec bond at the pseudoanomeric c-1 centre [180] . liminosugar c-glycoside, (à)-adenophorine (80, fig. 14a ), an enantiomer of natural iminosugar c-glycoside (þ)-adenophorine (81), was prepared together with it analogues via skeletal rearrangement of corresponding azepanes [181] . however, compound 80 and analogues were found to be weak but selective inhibitors of e. coli bglu. the c-propyl analogue, compound 82 with ic 50 ¼ 586 mm showed total selectivity for the bacterial ortholog. it was also superior to compound 80, its azepane precursor 83, and other iminosugars in the study which showed moderate selectivity with 3.1e18.1% inhibition at 1 mm. however, increasing the lipophilicity of azepane scaffold 84 via c-2 or n-alkylation, while tuning the configuration of alkyl and hydroxy substituents at c-2 and c-6 respectively (fig. 14b) , birthed e. coli bglu inhibitors with markedly increased potency and highly conserved selectivity [182] . sar analysis revealed that a combination of (6s)eoh unit and n-alkylation with hexyl, nonyl or dodecyl produced stronger inhibitors and their potency increased with increasing chain length. in contrast, (2r, 6r)-c-butyl and (2s, 6r)-cnonyl derivatives, compounds 85 and 86 respectively, were the most active c-alkylated analogues with ic 50 ¼ 261 and 27 mm respectively. compound 85 was stronger than its n-alkylated analogue, while compound 86 showed a compromised selectivity (ic 50 ¼ 97 mm against bovine liver bglu). overall, highly lipophilic compound 87, having (6s)en-dodecyl framework was the strongest inhibitor with ic 50 ¼ 3.30 mm, 3-fold superior potency to (6s)e n-nonyl analogue 88 (ic 50 ¼ 10.0 mm) and absolute selectivity for e. coli bglu. furthermore, substituent type and configuration at c-6 also influenced the inhibitory potencies of noeuromycin azepane analogues [183] . (6s)-configured compound 89 and 90 were weakly potent, compared to their inactive (6r)-configured analogues. compound 89 (ic 50 ¼ 139 mm) was 4-fold more potent than its 6hydroxymethylated analogue compound 90. incorporating the acetamido unit in siastatin b (56), while retaining the iminosugar c-glycoside scaffold via similar skeletal rearrangement of azepanes, afforded l-configured c-glycosides of 1-deoxynojirimycin (91) with weak inhibitory potencies [184] . sugar configuration at c-1 and c-2 (fig. 14d) , significantly influenced selectivity for ghs. hence, (2r, 3r)-configured molecules were selective inhibitors of e. coli bglu but inactive against bovine liver bglu, a-n-acetylgalactosaminidase and b-n-acetylgalactosaminidase. whereas, (2s, 3s)-configuration infused selectivity for b-n-acetylgalactosaminidase. consequently, (2r, 3r)-configured compound 92 with a rigid benzyl substituent emerged as the best e. coli bglu inhibitor in the series with ic 50 ¼ 90.7 mm compared to 37.2% inhibition at 1 mm of compound 93 with (2s, 3s)-configuration and butyl unit. the authors attributed these inferior activities to stereochemical mismatch between the l-configured units and dconfigured substrates of ghs. we also conceive that the presence of hydroxymethyl and not carboxylic unit (to mimic glucuronic acid) might also be responsible for the weak inhibitory potencies. this was indeed the case for 3,4,5-trihydroxypipecolic acids, uronic analogues of 1-deoxynojirimycin [185] . d-isomers were stronger than corresponding l-isomers, while the most active bglu inhibitors were those with better mimicry of glucuronic acid viz. dgluco and d-galacto configured units; compounds 94 and 95 respectively (fig. 15 ). compound 94 showed 3-fold selectivity for bovine liver bglu (ic 50 ¼ 70 mm), whereas compound 95 displayed an exclusive inhibition (ic 50 ¼ 86 mm). azoles are a prominent class of heterocycles with at least one nitrogen atom in their 5-membered aromatic ring. due to their structural rigidity and amazing physicochemical properties, which confers highly coveted and broad pharmacological activity spectrum and therapeutic potentials, they have remained a targeted scaffold of many synthetic protocols. members of this class include pyrazoles, imidazoles, thiazoles, triazoles, oxadiazoles, thiadiazoles and tetrazoles together with their benzo analogues i.e., indoles, benzimidazoles, benzothiazoles and benzotriazoles. these compounds also enjoy increased hydrogen bonding (h-b) capability furnished by ring n and/or o atoms for biomolecular targets binding. consequently, this section is an overview of reported bglu inhibitors bearing one or more azole nuclei. the critical focus is on the most potent inhibitor(s) in a given series, the pharmacological profile, structure-activity relationship (sar) and molecular docking analysis. bglu inhibitory potency (ic 50 ¼ 1.20e44.16 mm) on a set of imidazolylethylaryl carboxylates compared to reference inhibitor d-sal (ic 50 ¼ 48.38 mm) [186] . compound 96 (fig. 16 ) emerged as the most potent bglu inhibitor (ic 50 ¼ 1.20 mm) with 40-fold superior potency to d-sal. sar analysis supported by in silico studies articulated that compounds with electron-donating groups (edgs) displayed inferior inhibitory activities compared to those with electron-withdrawing groups (ewgs). moreover, molecular hybridization with indole nucleus resulted in a potent bglu inhibitor compound 97 with ic 50 ¼ 2.10 mm and 23-fold increased potency than d-sal. compound 96 and 97 displayed strong h-b interaction of indole nh unit and p-p interaction with active site residues of bglu. in vitro screening of imidazolopyridines ( fig. 17 ) for their bglu inhibitory potentials presented dihydroxy-substituted derivatives as promising inhibitors of enzyme activity [187] . (fig. 19) . however, replacing oh unit with more lipophilic meo or eto groups led to significant loss of activity. molecular docking analysis also disclosed the importance of iminic nitrogen and proximity of thiazole nitrogen to catalytic acid glu451 for strong inhibitory potency. compound 102 with adjacent oh units had a favourable fit into bglu catalytic pocket for stronger interactions with amino acid residues glu540, glu451 and tyr508. however, installing pyren-1-ylmethylenehydrazinyl moiety on thiazole skeleton improved bglu inhibitory potency [190] . comwith br, me and meo substituents were weaker inhibitors [191] . as a result, compound 108 with ic 50 ¼ 2.16 mm (fig. 21) , was the most potent inhibitor. it was 2 and 22-fold stronger than compound 109 and d-sal respectively. docking studies revealed that the free amino nh unit in compound 108 formed strong h-b interaction with oh unit of catalytic acid glu451. the dichloro substituents also substituted phenyl units at position-2 of benzimidazole core [192] . activity was dependent on the presence and position of cl and oh substituents hence 3,4-dichlorophenyl analogue 110 (fig. 22 ) was found with strongest inhibitory potency (ic 50 ¼ 6.33 mm). interestingly, introducing 5,7-dichloro unit on benzimidazole nucleus gave remarkable results as previously inactive molecules gained significant activity [193] . compound 111 emerged as the most potent inhibitor overall with ic 50 ¼ 4.48 mm and 11-fold stronger than d-sal. moreover, replacing an oh unit of the dihydroxy substituent with meo led to significant or total loss of activity. f, me, no 2 , naphthyl and anthracenyl units also gave inactive compounds. [194] . molecules containing ewgs no 2 , cl and f groups were superior in the series (fig. 23) . thus, the best activity was found with orthoakin to imidazole-indole hybrid compound 96 with ic 50 ¼ 2.10 mm (fig. 16) , molecular hybridization of benzimidazole with amide bond bioisostere, 1,3,4-oxdiazole, resulted in an isopotent hybrid 113 ( fig. 24 ) with ic 50 ¼ 2.14 mm [195] . again, ohsubstituted derivatives were stronger inhibitors compared to those containing f, cl and no 2 , me and meo substituents. docking studies revealed that the molecular hybrids adopted a linear configuration in the active site of bglu. the oxadiazole nucleus and central-phenyl ring of compound 113 formed strong h-b interaction with nh 2 unit of asn484 and phenolic oh of tyr508 respectively. compound 114 (ic 50 ¼ 3.14 mm) on the other hand interacted with catalytic acid glu451 and tyr508 via its central phenyl and phenol rings respectively. in another comparative study using 113 as lead but replacing benzimidazole with benzohydrazone unit (fig. 25) , the importance of benzimidazole nucleus to bglu inhibitory activity was established by the pronounced loss of activity [196] . nevertheless, oh-substituted derivatives and benzenetriol compound 115 emerged as the strongest inhibitor with ic 50 ¼ 7.14 mm. inhibitory potency was dependent on substituent's position in the order; para ˃ meta ˃ ortho for oh, no 2 and cl groups, while the presence of me or meo groups gave inactive compounds. molecular docking studies showed that inhibitory activity correlated strongly with the strength of h-b interaction hence the improved potency seen with oh-substituted derivatives. notably, the benzenetriol oh unit on compound 115 formed h-b interactions with glu540, asp207, tyr508, his385, and asn450, while the benzohydrazide unit interacted similarly with tyr508, glu540 and tyr504. in like manner, replacing the pharmacophores in compound 115 i.e. hydroxyl for methoxy and imine for more polar sulfonamide unit (fig. 26) , led to stronger bglu inhibitory potency for the resulting oxadiazole-benzenesulfonamides [197] . the most potent inhibitors were compounds 116 and 117 with ic 50 ¼ 2.40 and 6.34 mm respectively; compound 116 showed similar potency as compound 113. inhibitory activity was improved for parasubstituted derivatives, while ewgs produced stronger inhibitors than edgs. binding interactions in the active site of bglu especially h-b interaction of benzamide nh unit with glu451 established the improved activity of the sulfonamides compared to benzohydrazones. compound 116 formed h-b interaction via sulfonyl oxygens with asp207 and asn450, while the benzamide oxygen interacted in similar fashion with tyr508. additional ionic bonding between no 2 groups in compound 117 and glu451 also accounted for the improved potency. molecular hybridization (fig. 27) inhibitor d-sal respectively (fig. 28) . in silico studies of these benzothiazoles revealed that they adopted a linear conformation which allowed appropriate fit into the binding groove of bglu. ortho-oh unit on compound 120 formed strong h-b interactions with glu451 while the para-oh unit provided h-b interaction with asp207. the enzyme-inhibitor complex was stabilized in the active site through hydrophobic interactions of benzenetriol ring with indole nucleus of trp587, his385, asn484, tyr504, his509, arg600, and lys606. most importantly, all the active inhibitors were noncytotoxic in a cytotoxicity assay using mouse embryo fibroblasts (3t3-l1) and wistar rat hepatocytes (cc-1). benzothiazole and benzimidazole are bioisosteres due to their structural and pharmacological similarities; therefore, bioisosteric replacement of one for the other has been consistently explored in drug development. accordingly, bioisosteric replacement of the benzimidazole moiety in compound 113, to give new benzothiazole-oxadiazole hybrids resulted in equally potent bglu inhibitors [200] . the most potent compound 122 (fig. 29 ) with ic 50 ¼ 2.16 mm, was equipotent with compound 113. fascinatingly, compound 123 (ic 50 ¼ 4.38 mm) was also isopotent with similarly substituted compounds 121 and 111. further, docking studies of compounds 122 and 123 showed that h-b interactions of phenolic oh units with active site residues viz., glu451, tyr508, and asp207, favoured their strong inhibitory potency. moreover, compound 122 formed hydrophobic interactions with tyr504 and lys606 via its thiazole core and benzene ring respectively. the reduced potency of compound 123 was established in the strength of these interactions as well as the absence of additional van der waal contacts of benzothiazole ring in compound 122 with catalytic residues glu451 and glu540. in silico pharmacokinetic properties modelling of these inhibitors predicted good cell permeability and solubility. the compounds were also non-cytotoxic to 3t3-l1 and cc-1 cell lines. following a similar molecular development strategy leading to compound 122, new benzothiazole-hydrazone hybrids were assembled by deleting the 2-oxadiazolylphenol fragment in compounds 122 and 115 (fig. 30) [201] . compared to the parent compound series, the new hybrids had marked reduction in potency. the recurring pattern of reduced or abolished activity also persisted with me and meo substituents. nevertheless, compound 124 was 3.2.1.7. triazole. the triazole ring also affords potent bglu inhibitors. in vitro evaluations of 1,2,4-triazole-schiff bases [202] presented isatin-containing compound 125 (fig. 31) as the strongest inhibitor with ic 50 ¼ 2.50 mm and 19-fold superior activity than d-sal. cl, oh and no 2 substituents at ortho-positions also gave appreciable activities whereas me, meo, cumyl and other aryl derivatives were inactive. docking simulations of compound 125 in the active site of bglu revealed strong h-b interaction between isatin nh and catalytic residues glu540 and tyr504. the phenyl ring also provided p-anion and p-p interactions with glu451 and tyr504 respectively while van der waal contacts with lys606, tyr508, val410 and asn450 stabilized the inhibitor-bglu complex. however, amide bond bioisostere, 1,2,3-triazole, is a stronger bglu inhibitor compared to its 1,2,4-triazole isomer. molecular hybridization with carbazole [203] delivered eight compounds having ic 50 < 3 mm (fig. 32) . compound 126 (ic 50 ¼ 0.55 mm) was the most potent hybrid in the series and 83-fold stronger than d-sal. all the carbazole-1,2,3-triazole tethers were non-cytotoxic to 3t3 cells. 3.2.1.8. indole-based hybrids. a library of indole analogues containing the hydrazone unit in compound 115 have been examined for bglu inhibition [204] . evinced by the increased potency, the indole pharmacophore delivers stronger bglu inhibitors compared to benzothiazole and oxadiazole. for instance, the most potent inhibitor 127 with ic 50 ¼ 0.50 mm (fig. 33) , was 100-fold more potent than d-sal and 42-fold stronger than similarly substituted oxadiazole variant from compound 115 library. compounds 128 (ic 50 ¼ 2.40 mm) and 129 (ic 50 ¼ 2.50 mm) were also 3-fold and 43fold stronger respectively than their corresponding oxadiazole variants. moreover, substitution at ortho and para-positions gave stronger inhibitors compared to meta-position, while potency in monosubstituted analogues followed the order; f ˃ oh ˃ cl ˃ pyridyl ˃ no 2 ˃ meo. the excellent potency of compound 127 was afforded by strong h-b interaction of position-5-oh with glu451 and glu540 as well as position-4-oh with tyr508. indole and benzohydrazone nh units formed h-b interactions with asn502 whereas the ligandreceptor complex was stabilized by p-alkyl interaction of indole ring with trp528. expectedly, the reduced activity of compound 128 was seen in its weaker interactions in the active site of bglu. based on the pharmacological significance of thiadiazole pharmacophore and the promising inhibitory activity of indole hybrid compound 127, hybrids of indole-thiadiazole were assembled as new class of bglu inhibitors [205] . generally, thiadiazole nucleus infused stronger inhibitory potencies on the resulting hybrids compared to hydrazone unit. dihydroxy substituted compound 130 emerged as the strongest inhibitor with ic 50 ¼ 0.50 mm and equipotent as compound 127. ortho-substitution was more beneficial to potency than para and meta-substitutions, while inhibitors' strength followed the order; oh ˃ f ˃ me ˃ pyridyl ˃ cl ˃ no 2 (fig. 34) . however, bioisosteric replacement attempt with oxadiazole proved that thiadiazole unit is preferred for stronger inhibition [206] . the strongest potency remained with 2,3-dihrdoxy substituted derivative 131 (ic 50 ¼ 0.90 mm), although 2-cl derivative had an outlying potency. bazedoxifene (fig. 35) is a novel indole-based inhibitor of il-6/ gp130 for the management of triple negative breast cancer [207] . it is also a selective estrogen receptor modulator administered as co-drug with conjugated estrogens (duavee) in estrogen replacement therapy for the prevention of postmenopausal osteoporosis. albeit, the high ratio of circulating estrogen metabolites and parent estrogen aided by bglu deglucuronidation activity in the gut is considered a risk factor for postmenopausal estrogen receptor positive (erþ) breast cancer. accordingly, a study on the therapeutic utility of this combination drug in an ovariectomized mouse model showed significant reduction in faecal bglu activity without altering faecal microbiota diversity [208] . the study articulated the significance of bacterial bglu inhibition to improving the outcome of long-term administered estrogens for postmenopausal women or breast cancer patients. consistent with the excellent inhibitory potencies of indolebased compounds, a library of bis-indoles (fig. 36) have been reported as strong bglu inhibitors [209] . once more, the importance of (di)hydroxy substitution to potency was prominent. compound 132 emerged as the most active molecule with ic 50 ¼ 1.62 mm and 30-fold superior to d-sal. in silico studies suggested that h-b donor-acceptor potential of oh units on compound 132 significantly influenced ligand-receptor interaction. ortho-oh formed strong h-b with amino acid residues asp207 and tyr508, while para-oh interacted similarly with his385. arene-arene interaction of indole ring with tyr504 also aided the favourable binding to bglu. in another study [210] , both compound 132 and its 2,3dihydroxy compound 133 (ic 50 ¼ 1.2 mm) were the strongest inhibitors of bacterial bglu; albeit with moderate cytotoxicity against 3t3 mouse fibroblasts. the presence of n-phenyl substituted thiosemicarbazide unit however introduced marked increase in bglu inhibition of 1hbisindoles [211] . inhibitory potency for monosubstituted analogues followed the order f z cf 3 ˃ cl ˃ br ˃ me ˃ meo and ortho-substitution produced the best result (fig. 37) . accordingly, 2-f to glu540, asn450, lys606, trp528. tyr508 also formed h-b interaction with amide nh and arene-arene interaction with phenyl ring of tolyl unit. chalcones are both a class of naturally occurring flavonoid family and synthetically obtainable compounds with extensive therapeutic applications [213] . the presence of a highly reactive a,b-unsaturated ketone unit and delocalized electrons makes them coveted precursors for many synthetic manipulations and pharmacological explorations. the pro-inflammatory role of bglu in inflammatory disorders motivated the design of a series of (di)hydroxychalcones (fig. 39) , to inhibit the release of bglu from stimulated rat mast cells and neutrophils [214e216]. it was established that hydroxychalcones were stronger and selective inhibitors of neutrophil-derived bglu over mast cell-derived bglu. the best inhibitors were compounds 139 (ic 50 ¼ 0.6 mm; ˃ 160-fold selectivity) and 140 (ic 50 ¼ 1.3 mm; 7fold selectivity). sar analysis showcased the importance of a,bcompound 141 (fig. 40 ) has emerged as the most potent inhibitor with 75% inhibition at 10 mm and only 3-fold stronger than standard salicylic acid, amongst a series of chalcone-mannich adducts [217] . adopting a similar molecular design [218] , a library of chalcone-benzamides were found with slightly improved potency and sar analysis established the preference of ewgs over edgs for better enzyme inhibition. compound 142 containing similar 3-br substituent as compound 141, emerged as the most potent molecule (84.68% inhibition at 1 mm); 3-fold stronger potency than salicylic acid (24.77% at 1 mm). it was also non-cytotoxic in cck-8 assay in contrast to 2-fold increased cytotoxicity of equally potent 3-cf 3 analogue. notably, activity modulation by substituting trimethoxy unit for indole was unsuccessful [219] , leading to prominent reduction in percentage inhibitory activity of the chalcones (˃ 8-fold). structural development of a coumarin (chromen-2-one) compound 143 (fig. 41 ) recovered from virtual screening delivered a set of moderately potent inhibitors of bglu activity [220] . superior activity compared to d-sal (ic 50 ¼ 48.40 mm) was recorded compounds 144e147 with ic 50 values of 9.90, 11.70, 21.40 and 34.20 mm respectively. in another attempt [221] , despite different molecular tunings including polar oh and cl groups, the coumarin pharmacophore remained inactive against bacterial bglu. conversely, structurally isomeric flavenone (chromen-4-one) bearing a pyranose appendage, showed stronger inhibition of bacterial bglu [210] . compound 148 (fig. 42) , the most active inhibitor thereof with ic 50 ¼ 4.50 mm and 10-fold superior potency to d-sal, was totally non-cytotoxic against 3t3 mouse fibroblasts. in silico studies further disclosed the importance of pyranose ring in h-b interactions with active site residues glu503, asp161 and glu413. fascinatingly, introducing 1,3,4-oxadiazole pharmacophore to a chromen-4-one scaffold (fig. 43) , led to significant increase in potency [222] . the new hybrids exhibited consistent trend in their potency based on substituent type and position in the order; f > cl > me > no 2 > pyridyl > meo and ortho > para > meta respectively. thus on the other hand, azacoumarins (1h-quinolin-2-ones) having a basic nitrogen atom in place of endocyclic coumarin oxygen, are conferred with stronger and selective inhibitory potencies against bacterial bglu. plausibly, their admirable activity is provided by the ability to mimic or interfere the oxocarbenium ion-like transition state akin to iminosugars; thus, allowing the alleviation of druginduced toxicities and prevention of colon carcinomas. renowned examples in this class of bglu inhibitors are the strongly potent azacoumarins 151 and 152 (fig. 44) , identified from high-throughput screening [19, 223] . the compounds exhibited in vitro ic 50 values of 0.28 and 0.37 mm respectively, over 1000-fold selectivity for e. coli bglu and 100-fold increased potency than reference inhibitor glucaro-d-lactam 61. the inhibitors also maintained their potency in living bacterial cells with ec 50 ¼ 0.018 and 0.028 mm. other similarly active compounds (ic 50 (once daily), alleviated irinotecan (cpt-11) induced diarrhoea evident by a protected gi epithelium of balb/cj mice compared to bloody diarrhoea due to damaged tissues and glandular structure in those receiving cpt-11 alone [19] . pre-treating c57bl/6j mice with 10 mg of inhibitor 151 before intraperitoneal administration of ulcerogenic dose of nsaids e diclofenac (60 mg/kg), indomethacin (10 mg/kg) and ketoprofen (100 mg/kg), also successfully protected the mice models against nsaid-induced small intestine mucosal damage [224, 225] . moreover, compound 151 reduced all enteropathy parameters by inhibiting gi bacterial bglu-mediated hydrolysis of nsaid-acyl glucuronide in a concentration-dependent manner (ic 50 z 0.164 mm). interestingly, the compound did not alter drug's systemic exposure, hepatobiliary excretion of glucuronides and gi microbiota diversity. although it possesses a short half-life (˂1 h) and pan-cytochrome p450-mediated poor bioavailability (21%). however, an attempt to reduce the inhibitor's serum exposure for increased gi residence by replacing ethoxy unit with hydroxyl or morpholinyl groups led to inferior pharmacological profile compared to parent compound 151 [226] . further, compound 152 exerted 2-fold reduction in the severity of diclofenacinduced anastomotic leakage, without affecting drug's plasma concentration in wistar rats receiving 0.8 mg of the inhibitor and 3 mg/kg of diclofenac [227] . in contrast, rats receiving diclofenac only suffered severe leakage thus suggesting the inhibitor's potential clinical utility to improve anastomotic healing. emerging from the screening protocol which birthed compound 151, three piperazine-containing compounds 153, 154 and 155 ( fig. 45) showed promising inhibitory potentials against bacterial bglu [228] . though with slightly weaker inhibitory strengths (ic 50 the therapeutic significance of fused pyridinone-furans as antiinflammatory drug candidates via inhibition of neutrophil-derived bglu has been reported [234] . compounds bearing meo and cf 3 substituents on ring b (fig. 47) showed over 70% inhibition at 1 mm with no cytotoxic effects (<32% at 10 mm) in cck-8 assay as compared to reference salicylic acid (25% inhibition). replacing ring b with furan, thiophene or pyridine however gave poor inhibitors (<45% inhibition). compound 158 was the most potent with 75% inhibition. the inhibitory potencies of dihydropyrimidinone carboxylates ( fig. 48) , against bovine liver-derived bglu has reiterated that small polar substituents are necessary for strong enzyme inhibition [235] . appreciable potency (ic 50 ˂ 20 mm) was exclusive to cf 3 ˃ f ˃ oh ˃ thienyl ˃ cl substituted compounds in that order. whereas, meo, br, benzyloxy, furanyl, aliphatic alkyl or aryl units either reduced potency when co-substituted with polar f or oh groups, gave inferior activity with monosubstitution or rendered the molecule totally inactive. therefore, the most active compound 159 with ic 50 ¼ 9.38 mm, found favourable fit in the active site of bglu to form strong h-b interactions with key residues. nh of asp207 was both a h-b donor and acceptor to pyrimidinone carbonyl oxygen and free nh at position-1 respectively. carboxylate carbonyl oxygen interacted similarly with arg600 whereas position-3 nh interacted with catalytic residues glu451 and tyr508. however, pyrimidinetriones (barbituric acid) [236, 237] , exhibited inferior potencies compared to standard d-sal (ic 50 ¼ 45.75 mm), despite their similar binding interactions as compound 159 with active site residues and non-cytotoxicity to 3t3 cells. in a predating study, the structural homolog of pyrimidinone, quinazolinone [238] , exhibited a unique trend in inhibitory potency against e.coli bglu with significant tolerance for lipophilic alkoxy groups, although poor activity with methyl substituent persisted. the most active compound 160 (fig. 49) intriguingly, replacing alkoxy units with more polar oh, no 2 and cl substituents led to significant reduction in potency. inhibitory potency therefore followed the order; meo ˃ eto ˃ n(me) 2 ˃ no 2 ˃ oh ˃ cl and ortho ˃ para ˃ meta. importantly, the quinazolinone-based inhibitors were all non-cytotoxic to 3t3 cells. it is also noteworthy that a quinazolinone compound (table si) from ref. [223] , also showed strong inhibitory potency (ic 50 ¼ 1.90 mm) against bacterial bglu. the quinoline nucleus can be regarded as a household name in medicinal chemistry, due to its inexhaustible pharmacological application and occurrence in many clinically important natural products and synthetic molecules. the desirable pharmacokinetic profile and ease of accessibility with wide substrate tolerance for different synthetic protocols, also encourages its utility in countless synthetic explorations. research endeavours aimed at quinolinebased bglu inhibitors are therefore presented in this section. quinoline-3-carbohydrazides [239] , prepared analogously as hydrazone tethers above also holds promising inhibitory activities. similarly, oh unit at ortho-position yielded stronger inhibitors than f > cl > no 2 > pyridyl > thiophenyl > furanyl z me > meo, in that order. moreover, ortho-substitution consistently gave superior inhibitors compared to para-position, while meta-substitution conferred the weakest potency. 2 to 3-fold reduction in potency persisted when oh unit is substituted for meo unit (fig. 50) . hence, compound 162 (ic 50 ¼ 2.11 mm) and 163 (ic 50 ¼ 2.60 mm) emerged as the most potent inhibitors overall. docking studies revealed that oh unit at position-4 of quinoline ring fostered important h-b interaction with catalytic acid glu451, while carbonyl unit of hydrazone moiety formed h-b interaction with nh of tyr504. in another quest for new anti-inflammatory agents, quinolinefuran hybrids (fig. 51) were designed as inhibitors of bglu release from activated neutrophils [240] . sar analysis, established that 2-(furan-2-yl)quinolines (type a) were stronger inhibitors of inflammatory mediators than tricyclic furo[2,3-b]quinolines (type b). whereas, formyl unit favoured potency compared to acetyl, oxime, methyl oxime as well as both a,b-unsaturated butan-2-one and its saturated variant. therefore, non-cytotoxic compound 164 (ic 50 ¼ 5.0 mm) was the strongest inhibitor of bglu release with 3fold superiority to reference trifluoperazine. acetyl isomer compound 165, also had similar non-cytotoxic and strong inhibitory potency (ic 50 ¼ 7.5 mm). akin to azacoumarins (1h-quinolin-2-ones) 151 and 152, new quinoline-pyrazole conjugates were prepared via hit development protocol of compound 166 (fig. 52) identified from highthroughput screening, for the inhibition of intestinal bacterial bglu's hydrolytic activity on sn-38g fo alleviate cpt-11 druginduced toxicity [241, 242] . interestingly, all the resulting derivatives showed good selectivity for e. coli bglu except 2-cl, 3-oh, 3-me and 4-nh 2 substituted derivatives. the trend in inhibitory potency, based on substituent's position varied in the order; meta < ortho < para, while the presence of strongly hydrophilic oh, no 2 and nh 2 units at para-position was detrimental to potency. following oral administration to balb/cj mice for 5 consecutive days compared to compound 168 (40%). whereas, pharmacokinetic profiling of compound 168 revealed its lower plasma concentration and increased gi residence for improved intestinal bglu inhibition compared to azacoumarin compound 151. most importantly, oral co-administration of compounds 167 or 168 at 3 mg kg à1 day à1 for 10 consecutive days with 50 mg kg à1 day à1 intraperitoneal injection of cpt-11, protected balb/cj mice models against cpt-11 drug-induced intestinal mucosal injury, without altering drug's therapeutic efficacy. furthermore, mechanistic studies established that the presence of electronegative and electroneutral surface charges on e. coli active site pocket and the protonation of n-1 and n-5 atoms avails a ph-dependent and selective inhibition for the compounds (fig. 52) . consequently, compounds 167 and 168 are clinically viable agents for protecting against gi e. coli bglumediated mucosal damage and preventing the release of chemical carcinogens crucial to the development of precancerous lesions for colon carcinogenesis. the 200-fold increased inhibitory potency of benzohydrazideen-cyanoethyl tethers [243] , compared to parent compounds articulates the significance of a balanced molecular lipophilicity to bglu inhibition. o-alkylation with benzyl, benzoyl or tosyl groups slightly influenced potency for oh-substituted units; benzylation produced the best result (fig. 53) . hence, 169 (ic 50 ¼ 1.60 mm) and 170 (ic 50 ¼ 2.20 mm) were the most active conjugates in the series. similarly, phenoxyacetohydrazones [244] have displayed 2 to 5-fold improved potency compared to d-sal (ic 50 ¼ 48.40 mm). compounds 171 and 172 (fig. 54 ) emerged as the the desirable therapeutic significance of fused thienothiophenes has stimulated the synthetic exploration of a thienothiophene skeleton 173 (fig. 55) for bacterial bglu inhibition [245] . from the resulting thienothiophene library with interesting structural diversity, only compound 174 showed inhibitory activity against bacterial bglu with ic 50 value of 0.9 mm; 51-fold superior potency to d-sal. notably, the predicted pharmacokinetic properties using molinspiration and osiris calculations suggested that the inhibitor possesses good bioavailability and no toxicity risk as bacterial bglu inhibitor. in vitro study of phenyl disulphideebenzenesulfonamide tethers [246] , disclosed compounds 175 and 176 (fig. 56 ) as potent inhibitors of bglu (ic 50 ¼ 2.20 and 3.34 mm respectively), analogous to similarly substituted oxadiazole-benzenesulfonamide compounds 116 and 117 (fig. 28) . interestingly, bulkier phenyl disulfides 175 and 176 shared similar potency with lower molecular mass thiosulfinate 52, fig. 9 (ic 50 ¼ 3.60 mm). however, substitution at ortho-position gave stronger inhibitors than para-and meta-positions, in contrast to compounds 116 and 117 series. docking studies further revealed that the strong inhibitory potency of compound 175 is aided by the h-b interactions of sulfonamide nh and oxygen with tyr205 and asp207 respectively. the efficacy of urea unit for bglu inhibition was also examined using a library of no 2 substituted n-phenyl ureas [247] . therefrom, appropriate positioning of polar no 2 unit was important to inhibitory potency of examined molecules. compound 177 (fig. 57) , emerged as the only inhibitor with promising activity with ic 50 value of 3.38 mm. however, thiourea analogues bearing meta-cl substituent on n-phenyl ring [248] , were stronger inhibitors compared to those with unsubstituted n-phenyl ring or no 2 substituted ureas (fig. 58 ). akin to compound 141, thioureas containing piperazine unit also exhibited improved potency compared to their morpholine and piperidine analogues, while n-alkylation of piperazine with n-(o or p-methoxyphenyl) or n-(2-pyridyl), extant empirical data identified bacterial bglu as a chelating agent, since enzyme activity was totally lost in the presence of cu 2þ , hg 2þ and ag þ metal ions and restored in the presence of other chelating agents e versene and cysteine [249] . therefore, metal complexes with coordinatable metal centres exhibit significant bacterial bglu inhibitory activities. to this end, pd(ii) complexes containing aniline and triphenylphosphine ligands were synthesized [250] . para-chloroaniline derived metal complex 182 (fig. 59) , displayed the strongest activity against bacterial bglu with 98.5% inhibition and ic 50 ¼ 15.40 mm. it was also 2-and 5-fold superior to meta-chloroaniline derived and n-methyl substituted metal complexes respectively. similarly, n-heterocyclic carbene (nhc) complexes of au(i) [251] , as well as bis (nhc) complexes of au(i) and au(iii) [252] , containing hydroxy, chloride, acetoxy and acetonyl ligands were equally potent bacterial bglu inhibitors with ic 50 ranging from 0.14 to 2.60 mm. the strongest au(i) nhc complex 183 (ic 50 ¼ 0.14 mm) was 327-fold more potent than reference d-sal and 7-fold superior to strongest bis (nhc) complexes 184. nonetheless, undesirable cytotoxicity against 3t3 cells discomfits the therapeutic significance of these metal complexes. parallel to iminosugars 60e74, the inhibitory potencies of structurally similar glycopolymers (fig. 60 ) was dependent on the presence of carboxyl unit, type and configuration of sugar unit. hence, glycopolymers with d-glucaric pendants linked to the polymer frame at c-1 (185), were stronger inhibitors compared to glycopolymers linked at c-5 (186) or those bearing d-gluconic (187) [253], d-mannaric (188) [254] and shorter chain d,l-xylaric (189) and l-tartaric (190) [255] pendants. however, these glycopolymers only show >60% inhibition at millimolar concentrations. patents and patent applications disclosing potent inhibition of bglu particularly bacterial bglu and the therapeutic significance thereof, have been documented. we therefore review in this section, patents applications filed in the present millennium relevant to bglu inhibition. we have also included the only biomarker application of the enzyme filed within the period [256] . however, some of the patents and applications [257e263] emanated from published papers [19, 210, 228, 229, 241, 262] , reviewed in previous sections; therefore, only their summary is presented in table 3 . considering the limitations associated with traditional clinical assessments for periodontal diseases diagnosis and the improved reliability of bglu as a biomarker, a simple method requiring less expertise has been claimed to quantify elevated levels of the enzyme in the saliva of diseased patients relative to healthy ones, as a biomarker of disease risk and status [256] . the invention involves adding known b-d-glucuronide substrates (4-methylumbelliferone or phenolphthalein b-d-glucuronides) to a sample of patient's saliva in bglu activity assay and thereafter quantifying the amount of aglycone produced via fluorometry, colorimetry or spectrophotometry. the addition of a labelled polyclonal or monoclonal antibody specific for bglu to saliva sample and subsequent estimation of the amount of labelled antibody forming bglu-antibody complex was also claimed, as well as a test-kit for claimed methods. bacterial bglu-mediated hydrolysis of steroid glucuronides on the skin leads to body odours hence inhibitors of the process were developed and applied in deodorant and antiperspirant formulations [264] . the invention claimed that deodorant formulations with described compounds only inhibits bglu activity without altering the natural composition of skin microbiota; in contrast to bacteriostatic or bactericidal mode of action of prior arts. amongst the claimed inhibitors of different class, the strongest inhibition of e. coli bglu was found with galactaric acid (99% inhibition at 0.1% test concentration in water), as well as zinc glycinate and zinc gluconate; 99% and 97% inhibition respectively at 0.25% test concentrations. in the same vein, potent inhibitors of bacterial bglu activity on urine have found non-therapeutic application in hygiene and sanitary products for suppressing the generation of urine odour [265] . at 0.1 wt% in dipropylene glycol, all the claimed inhibitors viz. macrocyclic ketones, ketones, macrocyclic lactones, macrocyclic oxalactones, esters, aldehydes, alcohols, ethers and terpenes, showed over 60% inhibition of e. coli bglu. macrocyclic ketones were stronger inhibitors than others. consequently, the invention's most active inhibitor was compound 191 with 100%, 99.9% and 95.8% inhibition at 0.1, 0.01 and 0.001 wt% respectively. it was also effective after 48 h in suppressing the increase in urine odour when incorporated into different hygiene and sanitary products. phenoxy thiophene sulfonamides [266] were designed as adjuvants to eliminate the dose-limiting gi toxicity (diarrhoea) of cpt-11, through potent inhibition of bacterial bglu-mediated deconjugation of active metabolite's glucuronide (sn-38g) in the intestine; thus, improving the drug's therapeutic efficacy. the synthesis of 76 bglu inhibitors and 18 analogues of brite-355252 (compound 192) , the most active compound (ic 50 ¼ 20 nm), together with their therapeutic application was claimed. sar study of compound 192 analogues revealed that inhibitory potency was markedly dependent on n-piperazinyl pendant at meta-position of phenoxy ring. over 500-fold reduced inhibitory potency occurred with n-methylation (akin to compound 156), 15-fold reduction when appended at para-position and total loss of activity when removed. uninstalling the chloro unit on thiophene ring also slightly diminished potency by 5-fold. whereas, replacing naphthyl with substituted phenyl units afforded inhibitors with similar potencies i.e. ic 50 < 50 nm (table si) ; as a result, 193 was equipotent with 192. bglu is a physiologically important lysosomal glycosyl hydrolase with appreciable therapeutic potentials such as biomarker for disease diagnosis, endogenous bioactivator in prodrug monotherapy and enzyme replacement therapy. the enzyme's role in cell proliferation and inflammation also renders it a potential target for anticancer and anti-inflammatory drugs development respectively. moreover, since a significant number of commercially available drugs are metabolised by glucuronidation, hydrolytic activity (i.e. deglucuronidation) by bglu in human intestinal microbiota has been linked to colon carcinogenesis and genotoxicity as well as drug-induced dose-limiting toxicities of anticancer agents and nsaids, which thwarts their therapeutic potential and clinical utility. therefore, potent inhibition of bglu holds enormous clinical importance. generally, our literature survey found that a significant number of natural products-derived inhibitors display moderate inhibition of bglu, and increased potency is found with inhibitors containing a flavonoid skeleton. the physiological tolerance, acceptable toxicity and favourable pharmacodynamic profiles of these natural inhibitors, posits them as worthy scaffolds warranting witty molecular developments. in addition, iminosugars distinguish themselves as a unique class of natural product-inspired molecules with promising potentials regardless of their usually multiple synthetic steps. notable amongst these are the nojirimycin analogues and iminosugar c-glycosides, both conferred with highly selective inhibition of bacterial bglu. however, the inhibitory potency of these carbohydrate mimics relies on several factors such as sugar configuration, mimicry of glucuronic acid substrate and correct lipophilic balance. hence, to harness their remarkable potential, ingenious manipulations of the synthetic medicinal chemist interested in exploring their chemical space is expressly required. on the other hand, purely synthetic inhibitors show fascinating diversity in their inhibitory potencies and pattern, due to the plethora of pharmacophoric enrichments possible for a single molecular design. based on the foregoing, a comprehensive list of potent synthetic inhibitors (ic 50 5 mm) in this review is provided in table si of supporting information. evinced by their nanomolar ic 50 values, quinoline-pyrazoles (167 and 168), piperazinecontaining compounds (156 and 157; 192 and analogues) as well as the indole nucleus, are conferred with the strongest inhibition of bglu activity overall. the order of potency for hydrazone tethers was found as; bisindole ˃ indole > quinoline > thiazole ˃ benzothiazole z oxadiazole. whereas, no 2 , cl, particularly f and oh substituents at ortho-or para-positions usually produce stronger bglu inhibitors compared to their meta-substitutions. taken together, these suggests that the presence of polar groups with strong hydrogen bonding potential is crucial to inhibitory potency, while an indiscriminate increase in molecular lipophilicity is detrimental to strong bglu inhibition. consequently, we envisage that the model bglu inhibitor will be that which is appositely tuned in its lipophilicity and polarity for easy cell penetration, favourable fit into the binding/catalytic pocket of bglu for energetically stable binding and strong enzyme inhibition. we also perceive that rationale molecular hybridization of those active class of natural products and synthetic molecules will furnish stronger inhibitors of bglu with improved selectivity and acceptable toxicity profile. furthermore, we found that due to the mixture of electroneutral and electronegative spots on the surface of bacterial bglu binding pocket at physiological ph, in contrast to the electropositive spots for human bglu, the presence of a protonatable n-atom confers improved selectivity for bacterial bglu inhibition. this was particularly true for piperazine based inhibitors. therefore, we believe further probing of this phenomenon will allow structureactivity guided molecular tuning to afford stronger bglu inhibitors. to the best of our knowledge, mechanistic studies on the behaviour of these inhibitors is scanty in 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concentration il-1b: interleukin-1 beta il-8: interleukin-8 k cat : rate constant of catalysed reaction kda: kilodalton k i : inhibition constant k uncat : rate constant of uncatalyzed reaction lab glucuronide conjugate of sn-38 tnf-a: tumour necrosis factor-a udp: uridine-5 0 -diphosphate ugt: udp-glucuronosyltransferase the national research foundation (nrf) of south africa is appreciated for kic grant and other financial support. supplementary data to this article can be found online at https://doi.org/10.1016/j.ejmech.2019.111921. key: cord-309052-3h0g7s9v authors: alam, fiaz; khan, gul nawaz; asad, muhammad hassham hassan bin title: psoralea corylifolia l: ethnobotanical, biological, and chemical aspects: a review date: 2017-12-15 journal: phytother res doi: 10.1002/ptr.6006 sha: doc_id: 309052 cord_uid: 3h0g7s9v psoralea corylifolia l. (leguminosae) is a well‐known traditional medicinal plant used from ancient times for treatment of various ailments. it is widely distributed and an important part of therapeutics in ayurveda and in chinese medicines. the aim of this review is to present comprehensive and most up to date report on its ethnobotanical, ethnopharmacological, clinical, phytochemical, and side effects. studies on the ethnobotanical, ethnopharmacological, clinical, phytochemical, and side effects of p. corylifolia were published until year 2017 and were searched using various scientific databases. the scientific literature searched revealed that these plant species has been extensively investigated in vivo and in vitro for various biological and phytochemical studies. it has cardiotonic, vasodilator, pigmentor, antitumor, antibacterial, cytotoxic, and anti‐helminthic properties and locally used for alopecia, inflammation, leukoderma, leprosy, psoriasis, and eczema. so far, about a hundred bioactive compounds have been isolated from seeds and fruits, and most important compounds identified belongs to coumarins, flavonoids, and meroterpenes groups. this review article summarized the most updated scientific literature on bioactive phytochemical and biological activities of p. corylifolia. this article will be a useful addition to providing information for future research, and more standard clinical trials are needed for the plant to be used as therapeutic agent. the family leguminosae contains about 500 genera and is among the largest families of flowering plants. the plants of leguminosae are widely distributed, and in terms of number of specie, it is one of the largest terrestrial family of plants after orchidaceae and asteraceae (stevens, 2015) . the genera that belong to this family are important medicinally and contain a variety of biologically important molecules; p. corylifolia is an important part of therapeutics in ayurveda and in chinese medicines. the plant is cardio active and showed antimicrobial and cytotoxic properties. it is used as a pigmentor. the plant showed cytotoxicity against tumors and worms (baquar, 1989; rizvi, saeed, & zubairy, 2007; sharma, 2004) . in chinese medicines, the psoralea plant is considered warm by nature, and therefore shows many healing actions on kidney and spleen meridians (daiquan, 2000 (daiquan, -2006 . the seeds of p. corylifolia are used in indigenous medicine systems for healing of various ailments. the seeds are diuretic, aphrodisiac, laxative, anti-helminthic, and are used in febrile conditions. in ayurveda, the seeds are used in the form of paste and as an ointment for external as well as internal use for treatment of different conditions such as alopecia, inflammation, leukoderma, leprosy, psoriasis, and eczema (huang, 1998; judd, campbell, kellogg, stevens, & donoghue, 1999; sjc, 2015) . in india, the powder of seeds is mixed with haratalabhasma (yellow arsenic) and converted to paste with the urine of cow. this paste is used to treat leukoderma lesions. in another formulation, the mixture of powdered seeds with buttermilk have been used externally for treating ringworm and scabies. the seed oil is taken orally with betel nut leaf for treatment of leprosy. another skin condition, dermatosis, has been treated with adjuvants therapy of bakuchi (p. corylifolia) with other local plants such as amalaki and khadira. similarly, the oils of bakuchi and karanja are mixed with vaseline to treat chronic skin diseases (khare, 2008) . the seeds of the plant are also considered useful in bilious disorder, snakebite, and in scorpion sting. the seeds are also used in the production of perfumes (deshaprabhu, 1966; maisch, 1889; sharma et al., 2000) . the root of p. corylifolia has shown its effectiveness in dental caries. the fruits are aphrodisiac and have laxative effect, and the leaves are antidiarrheal (baquar, 1989; sjc, 2015) . the plant is also valuable in treating alopecia areata (dua, kumar, pandey, & kumar, 2013b) . in combination with haritka and gokshura, this plant is used for urinary frequency, and with ashwagandha and bala, it is used for treatment of reproductive diseases and cough. in chronic diarrhea and for treating cold symptoms, this plant is used in combination with nutmeg and haritaki (anderson & voorhees, 1980) . the seeds of bakuchi in powder form mixed with the decoction of bibhitaka (terminalia bellirica bark) and kaakodumbara (ficushispida) was effective to treat vitiligo. the infection of ringworm is treated with a combination of tila (sesame seeds) and bakuchi (gupta, dhar, & atal, 1978) . a combination of bakuchi with haratalabhasma provides relief against leukoderma when applied externally (khatune et al., 2002) . in japan, the plant extracted with alcohol has been used as an additive in processed foods and pickles (nadkarni, 1976) . when the fixed oils are removed, what is left after the seed cake are used as feed or manure due to the presence of nitrogen (6.7%) and the minerals (7.8%). volatile oils obtained from fruits have an irritant effect on the skin and mucous membranes and stimulate the voluntary muscles in high concentrations (chaudhuri, 2015; gidwani et al., 2010; huang, 1998) . p. corylifolia in the form of extracts have been used in various herbal formulations when combined with other herbs and used in handling psoriasis and many other skin disorders . this plant is also reported to be used in cardiac problems, asthma, and urinary discharge (kr, 1975) . it also has anti-leishmaniasis activity (ali, akhtar, sultana, baboota, & ahuja, 2008) . it is used to control watery stool, urinary frequency, and reproductive imbalances (pole, 2006) . in china, it is specially used against vitiligo disease (anderson & voorhees, 1980; khare, 2004) . p. corylifolia is available in the form of various ayurvedic marketed formulations in india and across the world, the most famous brands are safuf bars®, zimad kibrit®, svitrakaravati®, khadirarista®, algushadi yoga®, sarvangasundarigutika®, bhallatakawaleha®, maheshwa-raghrita®, ayorajodilepa®, brihatsomarajitaila®, somarajighrita®, bawchichurna®, etc. (ali et al., 2008; pole, 2006; qiao et al., 2007) . the investigation showed that p. corylifolia possessed a wide range of phytochemicals including flavones, coumarins, monoterpenes, chalcones, lipids, resins, stigmasteroids, and flavonoids. the volatile oils are also reported from this plant (zhang, zhao, wang, lu, & chen, 2016) . it is revealed that seasonal variation also effects the phytochemistry of p. corylifolia. mostly, the bioactive compounds are found to be concentrated in the seeds. the phytochemistry of this plant is discussed as follows. the whole plant of p. corylifolia was extracted with organic solvents such as petroleum ether and chloroform. the subsequent isolation methods lead to the purification of bioactive compounds, for example, psoralen, isopsoralen, corylifolin, corylin, and psoralidin (gupta, gupta, & gupta, 2013) . peng and colleague obtained a new compound identified as neo-psoralen from the whole plant of p. corylifolia in 1996 and elucidated its structure on the grounds of chemical indications and spectroscopic analysis (chaudhuri, 2015; gupta et al., 2013; table 1 and figure 2 ). it was already discussed that most of the active constituents isolated so far from p. corylifolia are part of the seed. sen and colleague extracted seed oil from p. corylifolia and found that the oil is unsaponifiable with boiling points 180-190°c. during the experiment, another compound was also identified as methyl glucoside with melting points of 105-127°c (chopra & chopra, 1933) . chopra and chaterjee, in 1927 , identified essential oil, a fixed oil and resin of dark brown color with some traces of alkaloids in p. corylifolia (chopra et al., 2013) . dymock studied the sugar contents, extractive matter, albumin concentraton, and ash value, and also found some traces of manganese in seeds of p. corylifolia. in continuation of research for compounds from the seeds of p. corylifolia, three more important components were fractionated and identified as bakuchiol a monoterpene phenol and the two novels dimeric monoterpenoids, bisbakuchiols a and b (panda, 1999) . a very important pharmacological compound known as bakuchiol has also been biosynthesized in 1983, and it was concluded that it is a derivative of phenylpropane pathway (banerji & chintalwar, 1983) . similarly, bisbakuchiols a and b structures were evaluated, and it was noted that dimeric monoterpenoid skeleton contains two monoterpenes, which are connected through a dioxane bridge (wu et al., 2007) . the low polarity ether extract of p. corylifolia seeds was investigated, and it revealed the presence of various ketones and aldehydes containing compounds such as corylinal, c-formylated chalcone, and isoneobayachalcone. a new isoflavone compound known as psorlenal was also identified in the seeds (gupta et al., 1978) . the same compounds, psoralen and isopsoralen, were also isolated by applying other chromatographic techniques such as high-speed counter-current chromatography (liu, li, sun, & kong, 2004) . the seed's sample has been the main focus for the search of bioactive compounds, and such an isolation procedure involving spectroscopic methods and crystal x-ray diffraction resulted in isolation of five novel compounds. these compounds are named as psoracorylifols a-e and chalcone and bavachromanol (yin, fan, dong, & yue, 2006) . similarly, three new flavonoid compounds named as corylifols a, b, and c and bavachalcone were also fractionated from p. corylifolia seeds. another compound known as bakuchicin was also identified from the seeds (yin, fan, wang, dong, & yue, 2004) . the seeds are also reported to contain some other flavonoids such as bavachinin (bcn), bavachin, isobavachin, and isobavachalcone (ibc). the glycosides identified in seeds of p. corylifolia were psoralenoside and isopsoralenoside, which were of the benzofuran type. p. corylifolia also reported to contain some polar compounds, namely, neobavachalcone, 7-methyl bavachin, and bavachromene. these compounds were isolated and identified from the insoluble portion of the ethanolic extract. these compounds identified as (khatune et al., 2004) 2 aryl coumarin coumarin seeds anticancer (limper et al., 2013) 3 astragalin flavonoid seeds antioxidant 4 bakuchiol meroterpene seeds/fruit anti-acne antibacterial (katsura et al., 2001; newton et al., 2002) antifungal (newton et al., 2002) , (hosamani et al., 2012; lau et al., 2010; lau et al., 2014; prasad et al., 2004; savoia, 2012; srinivasan & sarada, 2012; yang et al., 2006) retinal regeneration (seo et al., 2013) anti-aging (seo et al., 2013) estrogen receptor agonist, postmenopausal symptoms (lim et al., 2011) anti-diabetic (behloul & wu, 2013) lymphangiogenesis inhibition (jeong et al., 2013) anticancer (chen et al., 2010; li et al., 2016) 5 bavachinin flavone seeds antibacterial (khatune et al., 2004) estrogen receptor agonist (lim et al., 2011) lymphangiogenesis inhibition (jeong et al., 2013) osteoporosis (liu et al., 2014) anti-alzheimer (chen et al., 2013) carboxylesterase inhibitors 6 bakuisoflavone flavone fruit antibacterial (siva et al., 2015) 7 bakuflavanone flavone fruit antibacterial (siva et al., 2015) 9 bavachin flavnonoid seeds/fruit osteoblast 10 bakuchicin coumarin seeds topoisomerase inhibitor (sun et al., 2003) 11 bavachalcone chalcone seeds anticancer (shan et al., 2014) cvs protective effect (dang et al., 2015) 12 bavachinone a flavonoid fruit antibacterial (won et al., 2015) 13 bavachinone b flavonoid fruit antibacterial (won et al., 2015) 14 bavacoumestan c flavonoid fruit antibacterial (won et al., 2015) 15 corylifolinin chalcone seeds antibacterial (khatune et al., 2004) carboxylesterase inhibitors (sun et al., 2016) 16 corylifols prenyl flavonoid seeds antibacterial (yin et al., 2004) 17 corylifol a flavonoid seeds/fruit carboxylesterase inhibitors 18 corylifol b flavonoid seeds carboxylesterase inhibitors 19 corylifol c flavonoid seeds protein kinase inhibition (limper et al., 2013) anticancer (limper et al., 2013) 20 corylifol d flavonoid seeds anticancer (stomach; yang et al., 1996; teschke et al., 2014) 21 corylifol e flavonoid seeds anticancer (stomach; yang et al., 1996; teschke et al., 2014) 22 coryfolin flavonoid whole plant antioxidant, anti-diabetic (behloul & wu, 2013) 23 corylin flavonoid whole plant osteoblast wang et al., 2001) anticancer (shan et al., 2014) carboxylesterase inhibitors (sun et al., 2016) 24 coryaurone a flavonoid fruit antibacterial (won et al., 2015) 25 dadzin isoflavnoid fruit antioxidant (shinde et al., 2010) 26 dadzein isoflavnoid fruit antioxidant (shinde et al., 2010) antidiabetic (behloul & wu, 2013) topoisomerase inhibitor (sun et al., 2003) 27 dihydroxy coumestan essential oil component seeds insecticidal, genotoxic (khatune et al., 2002; dua et al., 2013b) 28 genistein isoflavone fruit ani-diabetic, anti-obesity (behloul & wu, 2013) , antioxidant (shinde et al., 2010) 29 hydroxy bukuchiol meroterpene seeds lymphangiogenisis inhibition (jeong et al., 2013) 30 hydroxypsoralenol a flavonoid fruit antibacterial (won et al., 2015) 31 hydroxypsoralenol b flavonoid fruit antibacterial (won et al., 2015) 32 types of esters were also studied in p. corylifolia, and psoralester and psorachromene were identified as two new metabolites. the lymphangiogenesis inhibition (jeong et al., 2013) anti-alzheimer (chen et al., 2013) carboxylesterase inhibitors 33 isobavachin flavonoid seed/fruit osteoblast (li et al., 2014) 34 isopsoralen furanocoumarin whole plant antiprotozoal 35 neobavaisoflavone seeds antibacterial (khatune et al., 2004) 36 psoralen furanocoumarin whole plant/root leucoderma, psoriasis anticancer (hao et al., 2014) , antioxidant , anti-alzheimer (somani et al., 2015) , collagengenesis 37 psoralidin coumarin whole plant/seed estrogen receptor modulator (liu et al., 2014; lim et al., 2011) antioxidant (wang, yin, zhang, peng, & kang, 2013b) , antibacterial (khatune et al., 2004) anti-diabetic (behloul & wu, 2013) , antiprotozoal anticancer (hao et al., 2014; limper et al., 2013; yang et al., 1996) , anti-depressent (farahani et al., 2015) 38 psoracorylifol d flavonoid seed lymphangiogenesis inhibition (jeong et al., 2013) psoracoumestan coumestans seeds essential oil anti-cancer (limper et al., 2013) 39 xanthoangelol chalcone seeds anticancer (limper et al., 2013) figure 2 structures of important compounds isolated from psoralea corylifolia psoralester is a 10-membered lactone compound and the latter is an isomer of already known compound bayachromene (tewari & bhakuni, 2010) . khatune and colleague isolated new coumestan derivative 6-(-3-methylbut-2-enyl)-6 n-7-dihydroxycoumestan while working on the chloroform soluble portion of the seeds of p. corylifolia (khatune et al., 2002) . coumestans-3, 5′-dihydroxy-6′, 6′-dimethyldihydropyrano (2′, 3′: 8,9) coumestan, 3-hydroxy-5′-(1hydroxy-1-methylethyl) 4′, 5′-dihydrofuro (2′, 3′: 8,9) coumestan, and sophoracoumestan a have been fractionated from the seeds of p. corylifolia. lin and kuo isolated two new benzofuran derivatives; corylifonol and isocorylifonol along with astragalin, p-hydroxy benzoic acid from p. corylifolia seed extract (lin & kuo, 1992) . in 1989, zaka and colleague investigated the lipid and fatty acid composition of p. corylifolia. the lipids recognized were triacylglycerols, diacylglycerols, free fatty acids, monoacylglycerols, hydrocarbons, wax esters, and polar lipids. the purified crude lipids of p. corylifolia seeds were analyzed by thin layer and gas chromatographic techniques. among the components, the major polar lipid was c18: the sticky and oily pericarp constitute the fruit of p. corylifolia, and chemical investigation revealed some similar compounds as already isolated from seeds. a new isoflavone, corylinin, (7,4′-dihydroxy-3′in another experiment, hplc protocol was applied to identify some isoflavonoids such as daidzein, genistein, and biochanin a (sehrawat, sangwan, & yadav, 2014) . further work on the fruit extracted with hexane showed the presence of a phenolic monoterpene known as bakuchiol (cui, taniguchi, kuroda, & hatano, 2015) . dried p. corylifolia fruit powder extracted with methanol and analyzed on hplc reverse column showed the presence of isoflavonoids known as genistein, daidzein, and biochanin a (hsu, wu, chen, yang, & wang, 2001) . raun and colleagues have isolated seven compounds from the fruit of p. corylifolia and established the structure of compounds after the spectroscopic analysis. the components identified were corylinin (new compound), psoralen, neobavaisoflavone, sophoracoumestan a, uracil, and daidzin (ruan et al., 2007) . in 2015, two more new flavonoids, bakuisoflavone, and bakuflavanone were isolated from the fruit of p. corlylifolia with antimicrobial activities (lee, kim, baik, ryu, & lee, 2015) . in one study, six new flavonoid compounds and a meroterpenoid were isolated and identified by spectroscopic methods from p. corylifolia fruits and displayed medium activity against staph. mutans (won et al., 2015) . the dried fruits of the plant was investigated, and n-hexane the roots of p. corylifolia has been investigated for bioactive compounds. it was found that furanocoumarins psoralen and isopsoralen isolated from a petroleum ether extract were responsible for the anti-feedant activity against instar spodoptera litura larvae (sah et al., 2006 ; figure 2 ). the above discussions about phytochemical investigation of different parts of p. corylifolia clearly indicates that this plant is a very useful source of variety of bioactive constituents including flavonoids, terpenes, glycosides, alkaloids, coumarins, and others. p. corylifolia is a widely used herb and have many diverse ethnopharmacological and medicinal applications. the numerous chemical and pharmacological research that have been carried out have resulted in the isolation of the diverse bioactive compounds that are summarized below. p. corylifolia proved a promising agent in anti-acne formulations due to the presence of phenolic compounds bakuchiol. it proved to be safe and non-irritant and can be used for longer periods of the day because it showed no irritation and is non-sensitized . one of the bioactive isolated compound "soralen" found to have the ability to stimulate the development of melanin, and therefore it is employed for leucoderma treatment (kim, shim, ahn, & jung, 2013) . the plant is also used against the skin disease known as psoriasis (chen, yang, & zhang, 2013) . in one experiment, seeds of p. corylifolia was extracted with hexane and oil in water, cream was prepared with stearic acid as a base. in the next step, an open clinical trial was conducted on 30 patients suffering from eczema for a period of 30 days. after 2 weeks of cream application, symptoms score reduced. final day observation revealed that the symptom scores for eczema reduced from 6.367 ± 1.098 to 0.333 ± 0.279 for length of the lesion, from 1.333 ± 0.994 to 0.165 ± 0.087 for exudation rate, and from 2.567 ± 0.504 to 0.165 ± 0.132 for the rate of itching. this formulation was compared with the placebo preparation, in which the formulated cream contained all the ingredients except for the hexane extract of p. corylifolia. this study concluded that this plant could be effectively used for the treatment of eczema (gidwani et al., 2010) . p. corylifolia has been tested for antibacterial activity. wang et al. nine compounds exhibited significant antibacterial activity against sa and s. epidermidis (yin et al., 2004 that showed 11.5 mm zone of inhibition (acharya et al., 2015) . p. corylifolia in the form of the mouth rinsing solution has prevented the growth of s. mutans bacteria in a very low concentration. along with mouth rinsing ability, the ethanol extract of p. corylifolia was also reported to inhibit the human gingival fibroblast. in the same series of experiments, it was concluded that the extract is safe to use and has no toxic effect in normal doses . in 2015, two more new flavonoids, bakuisoflavone, and bakuflavanone were isolated from the fruit of p. corylifolia and were tested against the strains of mrsa (mrsa481 and mrsa 584) and it was found that two compounds showed some good antibacterial effects with mic values of (>32 (>9.4) and >32 (>9.4)) and (>32 (>9.5) and >32 (>9.5 μg/ml)), respectively . tissue culture studies showed that jasmonic acid treated plants of p. corylifolia enhanced psoralen content in leaves and roots of p. corylifolia. the methanol extract of root sample displayed effective antimicrobial activity against tested bacterial and fungal pathogens in range 25, 50, and 75 μg/ml. most effective activity 28 mm zone of inhibition was observed against p. aerugenosa at 50 μg/ml (siva et al., 2015) . p. corylifolia was also tested against the microbes sa, pseudomonas aeruginosa, and candida albicans, which are known to contaminate the cosmetics products. in the 96-well microplate assay, it was found to have antimicrobial activity . the a phenolic compound bakuchiol extracted from p. corylifolia (seeds) exhibited antifungal activity against many strains of pathogenic fungi, (hosamani, lakshman, & sandeepkumar, 2012; lau et al., 2010; lau et al., 2014; newton et al., 2002; prasad, anandi, balasubramanian, & pugalendi, 2004; savoia, 2012; srinivasan & sarada, 2012; yang et al., 2006) . in another study, activity was found against other fungi such as alternari brassicae, aspergillus niger, fusarium oxysporum, and rhizoctonia cerealis, in which mycelial growth was inhibited (satish, raghavendra, & raveesha, 2009; vonshak et al., 2003; yang et al., 2006) . in one study, p. corylifolia significantly reduced the incidents of the anti-worm property of the seeds of p. corylifolia is clinically proven on roundworms and flatworms (gidwani et al., 2010) . the seeds and the leaves of p. corylifolia was extracted with water and alcohol, and were tested on the spontaneous movements of setaria cervi whole worm and again on the isolated nerve muscle preparations. the survival of the microfilariae was tested in vitro. the dose required to inhibit the movements of whole worm and nerve muscle preparations for alcohol extracts of leaves were 160, 30, and for seeds were 50, 20 μg/ml (maurya, singh, & seth, 2014; mendam, kavitha, & naik, 2015; qamaruddin, parveen, khan, & singhal, 2002) . volatile oil extracted from the seeds of p. corylifolia displayed strong toxicity against both larvae and adult of the southern house mosquito, the bioactivity guided isolation from chloroform extract of seeds leads to the identification of pure compound, 6-(-3-methylbut-2enyl)-6 n-7-dihydroxycoumestan and found active against larvae and adult cx. quinquefasciatus. the same compound has also showed activity against the red flour beetle, tribolium casteneum hebrst. in this detailed study, both the male and female adults were exposed to the compound for 24-72 hr period and a range of ld 50 were calculated for dose starting from 400 to 1600 ppm and doses were used in five replications. it was concluded that the isolated coumestan compound can be a useful botanical insecticide (dua, kumar, pandey, & kumar, 2013a; khatune et al., 2002) . an external protozoan parasite ichthyophthirius multifiliis (also called "ich") has been reported to infest freshwater fish species. the p. corylifolia extracted with methanol showed excellent activity against i. multifiliis theronts in concentration of 1.25 mg/l or more when was exposed for a period of 4 hr. the p. corylifolia extract at 5.00 mg/l concentration has caused 100% mortality of protomonts and 88.9% of encysted tomonts. it was found that longer period (24 hr) and higher concentration (5.00 mg/l) caused the significant reduction of the survival rate and reproduction of tomont of i. multifiliis, which were exited from the fish after in-bath handling in situ (ling et al., 2013) . p. corylifolia has been found to be an alternative to malachite green to control i. multifiliis, an external protozoan parasite. the screening showed that p. corylifolia extract have the maximum activity against i. multifiliis theronts. when the experiments were conducted in vivo, at 1.25 mg/l or more concentrations of methanol extract of p. corylifolia, it caused 00% mortality of theronts during the 4 hr of exposure (ling et al., 2013) . this study showed the damaging effect of p. corylifolia against i. multifiliis trophont in situ. the same study leads to the evaluation of the activity of antiprotozoal compounds extracted form p. corylifolia against i. multifiliis. the two bioactivity guided isolated compounds, isopsoralen and psoralidin, were assessed. in comparison, study of psoralidin and isopsoralen, the inhibitory activity of psoralidin, was found more efficient. further, when experimented in vivo, the compound psoralidin at 2.5 mg/l, efficiently reduced the theronts numbers in infected fish over an exposure period of 5 hr. this study showed that psoralidin could be a very good candidate for the formulation as a commercial drug against i. multifiliis . the compounds from p. corylifolia were found to have a protective effect when tested against retinal damage caused by oxidative stress. to evaluate the effects of bakuchiol on the cell viability of dif(park et al., 2005) . a recent and very useful research on the same subject of hepatotoxicity shows that the isolated compound bakuchiol when administered at a dose of 52.5 and 262.5 mg/kg for 6 weeks in rats, many abnormalities were observed in the bakuchiol-treated groups including suppression of weight gain and food intake, change of some parameters in serum biochemistry, and increased weight of liver. the mrna expression of cyp7a1, hmg-coa reductase, pparα, and srebp-2 decreased in bakuchiol-treated group, the expression of bsep increased in bakuchiol-treated low dosage, and the expression of bsep decreased in bakuchiol-treated high dosage. it was concluded that bakuchiol could induce cholestatic hepatotoxicity, suggesting potential hepatotoxicity. the mechanism may be related to effects on liver lipid metabolism (li et al., 2017) . in one study, six compounds isolated from p. corylifolia were studied for their binding affinities for estrogen receptors, erα and erβ, using the yeast transactivation test. among the compounds, bakuchiol was in another study, psoralidin activity as er (α and β) agonist was evaluated in endometrial and human breast cell lines. psoralidin at 10 μm was able to get the highest reporter gene expression conforming to that of e2-treated cells and such an activation of the ere-reporter gene by psoralidin was totally stopped by the treatment of a pure er antagonist, indicating that the biological actions of psoralidin are intermediated by er. psoralidin was also able to stimulate the endogenous estrogen-responsive gene (ps2) in mcf-7, the human breast cancer cells. it was observed that activation of the classical er-signaling pathway by psoralidin is mediated via induction of er conformation by psoralidin and direct binding of the psoralidin-er complex of the eres present in the promoter region of estrogenresponsive genes. lastly, molecular docking of psoralidin to the ligand-binding pocket of the erα exposed that psoralidin is able to mimic the binding interactions of e 2 , and therefore, in the cellular environment it could act as an er agonist (liu et al., 2014) . psoralen isolated from p. corylifolia fruits were investigated as an inhibitor of ache enzyme in an attempt to explore its potential for the management of alzheimer's disease. the concentration of psoralen used was 25-400 μg/ml. it inhibited the ache in a dose-dependent way in animal models. adult male wistar rats, weighing 180-250 g, were used in the study. while a molecular docking study was also carried out, which showed that psoralen binds well within the binding site of the enzyme showing interactions such as π-π stacking and hydrogen bonding (somani et al., 2015) . although the activity measured in this study was moderate when compared with the standard compound used, despite that, the compound could serve as lead for synthetic analog preparation to improve the inhibitory activity. p. corylifoia also found to possess antidepressant activity. marzieh sarbandi farahani and colleague mentioned the mechanism of action of the plants with antidepressant action and the chemical components isolated from them. they mentioned that psoralidin isolated from seeds of p. corylifolia modify the hypothalamic-pituitary-adrenal axis (farahani, bahramsoltani, farzaei, abdollahi, & rahimi, 2015) . a similar study was conducted on psoralidin by yi and colleague on the icr strain of male mice. the dose was administered orally in forced swimming test and they observed the increased levels of 5hydroxytryptamine and 5-hydroxyindoleacetic acid in the brain and an altered dopamine level. the mechanism for antidepressant activity was proposed to be through involvement of monoamine neurotransmitter and the hypothalamic pituitary adrenal axis systems (yi et al., 2008) . some previous studies are also available, for example, one study was conducted on mice models and it was concluded that furocoumarins were actually responsible for antidepressant activity. in this study, the well-established antidepressants were used as standards for comparison with the seed extract of p. corylifolia. the dose range used was 7.5 to 100 mg/kg in comparison with amitriptyline (10 and 20 mg/kg) and fluoxetine (13 mg/kg). this study was well designed and results indicate the potential of the seed extract as competitive antidepressant when compared to the conventional therapeutic agents (chopra et al., 2013) . p. corylifolia also has a wide range of antioxidant activity. different compounds isolated from p. corylifolia were tested for their antioxiin the understanding of the reputation of this plant species in medicines now, attention has been given to produce callus culture. in one study, relationship between isoflavone and antioxidant activity of p. corylifolia cultures were experimented, and it was found that root-derived callus cultures produced more daidzein, whereas leafdervied callus produced more genistein, and this enhanced production was related to enhanced antioxidant activities (shinde, malpathak, & fulzele, 2010) . one of the isolated compound, psoralen showed the promising antioxidant activity (ic 50 value = 1.10 ± 0.60 μg/ml) against the superoxide anion production by human neutrophils in response to formyl-lmethionyl-l-leucyl-l-phenylalanine/cytochalasin b (fmlp/cb; chen et al., 2011). p. corylifolia extract possesses anti-diabetic activity by its action as the protective effects on pancreatic β cells (behloul & wu, 2013) . a more detailed biochemical study was conducted on the aqueous extract of seed of p. corylifolia that caused a significant recovery in the activities of hexokinase, glucose-6-phosphatase, and glucose-6-phosphate dehydrogenase and antioxidant enzymes such as peroxidase, catalase, and superoxide dismutase, along with the lipid peroxidation level in liver tissue and serum transaminase, and corrected the fasting blood glucose level in streptozotocin-induced diabetic rats at a dose of 20 mg/0.5 ml water/100gm body weight (ghosh, bera, chatterjee, ali, & debasis, 2009 ). p. corylifolia has been the part of many ayurvedic formulation that are used for the treatment of various central nervous system conditions such as for neurotropic activity and as central nervous system protective agent (goel & ojha, 2015) . based on such report, a study was conin another study, it was revealed that ibc, a flavonoid from p. corylifolia, has the ability to ameliorate the neuronal injury in brain diseases related to inflammation, and this was accomplished through inhibition of lipopolysaccharide induced intercellular adhesion molecule-1 expression and leukocyte adhesion to brain endothelial cell by blocking toll-like receptor 4 signaling . various studies on animals showed that genistein has the ability to decrease body weight by decreasing food intake. it also reduced the fat pad weight and enhanced the apoptosis of adipose tissues. for example, one such study was conducted on ovariectomised mice. this well-known trihydroxyflavone, genistein, has also been isolated from p. corylifolia, exhibited a potential anti-obesity and obesity related low grade inflammation activities through multiple mechanisms and cell signaling pathways. p. corylifolia extract possesses anti-obesity and antdiabetic activity by its action on adipocyte life cycle, obesity-related low-grade inflammation, and oxidative stress (behloul & wu, 2013) . the well-known chinese herb p. corylifolia l. (scurfpea fruit) has been employed for the treatment of bone fractures and also for joint diseases for thousands of years. p. corylifolia also improved the pathological bone condition, hyperosteoidosis, by increasing the serum inorganic phosphate level at a dose of 30 mg/kg. it was observed previously that the extract markedly decreased osteoid volume and there has been improvement in bone calcification (miura, nishida, & linuma, 1996) . the flavonoids of corylin and bavachin has the osteoblastic proliferation stimulating activity in umr106 cell line cultured in vitro (cho et al., 2001; wang, li, & jiang, 2001) . p. corylifolia extract when administered orally to ovx rats, it was noted that there was a decrease in urinary calcium excretion and serum osteocalcin at a dose of 25-50 mg/kg body weight. the experiments in this study showed that the extract also increased the bone mineral density and bone formation at 50 mg/kg bw (tsai et al., 2007) . such experiment, which were extended to 3 months, it can be concluded that p. corylifolia extract can be used at postmenopause state to prevent the osteoporosis. a further in depth study is still needed to make a therapeutic candidate. this study leads to the isolation of the compound responsible for the mentioned activity by weng and colleagues. the isolated compounds from p. corylifolia, known as bakuchiol and bavachin, showed to prevent the estrogen deficiency by inducing the upregulation in primary human osteoblast differentiation (weng et al., 2015) . an advanced herbal formula containing psoraleae fructus has previously showed promising bone protecting effect when tested in rats, and later on showed excellent results in women with osteoporosis. this herbal formula could efficiently have promoted the osteogenesis and suppress the adipogenesis in mesenchymal stem cells (siu et al., 2013 ). an hplc analysis was carried out to study the important constituents in scurfpea fruit. in the method employed, the compounds were identified by comparing their retention indexes with standard substances and it resulted in the identification of 11 compounds. the biological methods such as mtt and alp were employed to study the osteoblasts proliferation and differentiation activity. bavachin and isobavachin showed significant cell proliferation by stimulation, the compound bakuchiol displayed higher effect to boost osteoblasts differentiation. from the results, it was hypothesized that prenyl group as a side chain might be responsible for the activity mentioned, because this structural component was found as a common entity among the compounds tested for activity (li et al., 2014) . previous surveys revealed bakuchiol and bavachin, the two important components of p. corylifolia l., showed osteoblastic property. both the compounds displayed the prevention of bone loss caused by deficiency of estrogen in overiectomized animal models such as rats. one of in vitro study proposed that bavachin and bakuchiol caused the induction of primary human osteoblast differentiation by up regulating the wnt signaling pathway. this research proposes that boneprotective role makes these two compounds a promising and safe estrogen supplement for the estrogen replacement therapy (weng et al., 2015) . in one investigation, the compound psoralen with different concentrations (1, 10, and 100 μm) was tested on chondrocytes isolated from rats at 3-and 9-day intervals. it was found that at the low dose concentration psoralen was safe toward chondrocytes; however, at higher dose suppression of chondrocytes, proliferation was observed. the compound psoralen also increased the synthesis of type ii collagen at 100 μm, by 0.48-fold on day 3 and 0.56-fold on day 9. this was a detailed study, including mts assay, alcian blue colorimetry, western blotting, and qrt-pcr. the compound psoralen was also tested for cytotoxicity and exhibited low cytotoxicity toward chondrocytes at a dose range of 1-10 μm. a much higher dose of 100 μm suppression of chondrocytes proliferation was observed. the compound psoralen caused the inhibition of the type i collagen in gene expression and also in protein synthesis. it was concluded that psoralen could be an important biological compound for triggering the cartilaginous cellular functions of chondrocytes . the (jeong et al., 2013) . this was the first kind of study on p. corylifolia. the plant p. corylifolia extract neutralized the coagulation of caused by naja naja karachiensis snakebite when compared with the antidote used as a standard. the snake venom was experimented on human plasma (citrated) to evaluate its effect on activated partial thromboplastin time (aptt), prothrombin time (pt), and thrombin time (tt). snake venom (200 μg/ml) was found to delay pt (13 ± 0.57 to 23 ± 0.57 sec), aptt (35 ± 1.52 to 48 ± 2.0 sec), and tt (13 ± 0.57 to 33 ± 0.57 sec). pt and tt were prolonged, and it suggested the occurrence of thrombin-like or plasminogen activating enzymes (asad et al., 2013; asad et al., 2014) . a further in depth study of this activity is still underway in the author's laboratory. the extract of seeds of p. corylifolia have been reported to have stimulant activity against natural killer cells when tested in mice. this study report that the extract also modulates the antibody dependent cellular toxicity. during tumor development, the seed extract also inhibited the antibody complement mediated cytotoxicity. the study was conducted on balb/c male mice. the dose of 100 mg/kg was administered intraperitoneally. blood collected from punctured heart and serum was separated to study the antibody complement-mediated cytotoxicity. the natural killer cells were removed from spleen, and antibodydependent cellular cytotoxicity was assessed (latha, evans, panikkar, & jayavardhanan, 2000) . the isolated compounds from p. corylifolia including arylcoumarin and psoracoumestan showed strong anticancer potential by strongly hepatocarcinoma cells, it showed its inhibitory activity by inducing the mechanism of apoptosis (guo, liu, ye, & han, 2011; jiang & xiong, 2014; khan, iqbal, ahmed, & jamil, 2015; mohammadparast, rustaiee, rasouli, zardari, & agrawal, 2014; nehybova, smarda, & benes, 2014; rajan, tripathi, variyar, & pandey, 2014; tang et al., 2011; wong & rabie, 2011; yang et al., 2012) . similarly, two more compounds from the same specie identified as ibc and bcn attenuate aβ42-induced cell toxicity. the investigation was carried out on yeast two-hybrid system (chen et al., 2013) . during this study, eight compounds were tested, and among them ibc (3 μm) and bcn (30 μm) were proved to be active at non-toxic concentrations. the results were confirmed by a standard tht fluorescence method. the compound ibc also exhibited strong inhibitory effect on tht fluorescence, and bcn showed more efficient activity, which was comparable with the reference. moreover, the determination of ic 50 of ibc and bcn in the tht assay were about 25 and 45 μm, respectively. psoralidin in another study, caused the generation of reactive oxygen and it also thought to cause the inhibition of a549 cell proliferation. the method adopted was mtt assay. this study was designed to study the relationship of time and concentration used. the ic 50 values obtained after 24-, 48-and 72-hr treatment were 19.2, 15.4, and 11.8 μm, respectively. (hao, zhang, zhao, & chen, 2014) . another evidence of anticancer activity came from the compound bakuchiol that suppressed the testosterone induced cell proliferation and gene expression in lncap cells. this study was designed to explore the bakuchiol action in the androgen-dependent pca cell line (lncap). mtt assay and real-time pcr method were employed. the ic 50 of bakuchiol to androgen receptor was 8.87 × 10 4 , which was similar to the standard flutamide (10.00 × 10 4 ; miao et al., 2013) . these experiments showed that bakuchiol is a useful agent for drug development for androgen dependent pca. the same compound, bakuchiol, has also showed a strong anticancer action against human lung adenocarcinoma cell line a549 and showed much better results than its analogue resveratrol. ic 50 of bakuchiol at 72 hr was 9.58 ± 1.12 μmol/l, much lower than that of resveratrol (33.02 ± 2.35 μmol/l). bakuchiol triggered the process of apoptosis to a higher level, compared with resveratrol. it was also noted that oxygen species related apoptosis also contribute the cytotoxic properties of bakuchiol, and therefore, it also supports the use of bakuchiol against non-small-cell lung cancer. (chen et al., 2010) . bakuchiol also showed very selective clearance activity in hepatic stellate cells by a mechanism involving apoptosis. this study showed that p. corylifolia also has anticancer activity in liver cancer (chen et al., 2010; yang, paik, cho, cho, & kim, 2008) . in search of cytotoxic compounds from p. corylifolia, two isoflavnoids were isolated, named as corylifols d and e from the ethyl acetate extract. similarly, psoralidin was also found active against stomach carcinoma cell lines (teschke, wolff, frenzel, & schulze, 2014; yang et al., 1996) . bakuchiol is also an active ingredient of the dried ripe fruit of p. corylifolia that and corylin from p. corylifolia has been investigated against udp-glucuronosyltransferases and showed strong inhibition (shan et al., 2014) . it also inhibits lipopolysaccharide-induced endothelial-mesenchymal transition via down regulation of the nf-κb-snail signaling pathway (jung et al., 2015) . in one investigation against dna polymerase enzyme, p. corylifolia extract showed strong inhibitory activity. importance of isolated components from p. corylifolia is obvious from the fact that compounds such as psoralen is being produced from callus derived from various plant portions. in one experiment, it was found that in the in vitro conditions, cinnamic acid proved a very strong precursor of psoralen pathway that induced a maximum amount of psoralen (mohammadparast, rustaiee, rasouli, zardari, & agrawal, 2014 succeeding experiments with many kinase inhibitors propose that pf-mediated degradation of cyclin d1 and cdk4 is dependent on erk1/2 and/or gsk3β (park, sung, song, & jeong, 2016) . the crude extract of p. corylifolia with solvent ethanol was found a strong dna polymerase inhibitor of dna replication enzyme in an activity directed isolation assay that resulted in the purification of novel compound corylifolin, bakuchiol, neobavaisoflavone, and resveratrol. in a similar enzyme assay, some topoisomerase ii inhibitors were also isolated, namely, daidzein and bakuchicin (sun, woo, cassady, & snapka, 2003) . many studies have been designed so far to study the behavior of p. corylifolia extract and isolated compounds on important enzyme. additionally, the inhibition kinetics were calculated by dixon and lineweaver-burk plots for the inhibitory activities toward ces1. the inhibition kinetic parameters (k i ) were calculated to be 5.3, 9.4, 1.9, 0.7, and 0.5 μm for neobavaisoflavone, corylifolinin, coryfolin, corylin and bcn, respectively. it was concluded that this inhibition by the constituents might be responsible for the possible adverse effects of fp through the disrupting ces1-catalyzed metabolism of endogenous substances and xenobiotics (sun et al., 2016) . cytochrome p450 (cyp) is an assembly of heme-containing enzymes fixed essentially in the lipid bilayer of the endoplasmic reticulum, and helps metabolize several drugs and carcinogens. the plant p. corylifolia has been reported to be used in cardiac problems in traditional medicine (kr, 1975) . bavachalcone, a compound from p. corylifolia, has reported to have increased the luciferase activity of the manganese superoxide dismutase (mnsod) promoter and enhanced mnsod mrna and protein expressions. further, it was found that bavachalcone suppressed the mitochondrial superoxide production in endothelial cells. on the other hand, bavachalcone (in concentration range of 1, 2.5, and 5 μmol/l for 24 hr) stimulated liver kinase b1 and ampkα phosphorylation in a converse manner. mrna interfering by using short hairpin rna (shrna) of amp-activated protein kinase (ampk) inhibited bavachalcone-induced mnsod expression. moreover, ampk reduced by shrna-ampk reversed the inhibition of bavachalcone on mitochondrial superoxide production in endothelial cells. these results showed that bavachalcone could shield the endothelial function by enhancing the ampk activity and mnsod expression and lowering the mitochondrial oxidative stress, which is considered to be the key etiological reason in cardiovascular diseases (dang et al., 2015) . many herbal remedies, including essential oils, contain psoralen, and methoxy psoralen are reported to cause photosensitivity in the form of erythema and blisters (koh & ong, 1999) . p. corylifolia has been the part of many herbal remedy used to treat vitiligo and patients using such treatments in the form of creams are also reported to experienced erythema when exposed to sunlight (maurice & cream, 1989) . p. corylifolia is frequently indicated for vitiligo in india, and it contains psoralen, isopsoralen, and psoralidin. its extracts when tested on guinea pig skin have been stated to possess potent sensitizing action (pathak, daniels, & fitzpatrick, 1963) . another study reported the gonadal toxicity. although the ethanol extract of p. corylifolia seeds are proposed to use in processed food preservation, but it showed toxicity when tested on male and female rats. the period of the experiment was 90 days, and various concentrations were administered were 0%, 0.375%, 0.75%, 1.5% or 3.0%. histopathological investigation showed atrophy of seminiferous tubules, leydig cells, seminal vesicles, and prostate cells were observed in male rats administered with the 1.5% and 3.0%. with the same concentrations, the female rats showed a reduced number of corpora lutea in the ovaries and less frequent endometrial glands in the uterus. it was suggested that the extract caused the hypothalamus-pituitary-gonadal axis (takizawa et al., 2002) . in one investigation, p. corylifolia and its natural compounds (bavachin, corylifol a, neobavaisoflavone, ibc, and bcn) were evaluated for its potential toxicity, and results showed it had a potent inhibitory effect against human udp-glucuronosyltransferase 1a1 (ugt1a1), and it is considered as main stimulant for p. corylifolia related toxicity, including hepatic injury and raised bilirubin levels . in another study p. corylifolia extract and fractionated compounds such as psoralen and isopsoralen were incubated with the recombinant cyp3a4 enzyme or differentiated huh-7 and heparg cells. p. corylifolia extract, psoralen, and isopsoralen caused the inhibition of concentration cyp3a4 activity in a dose dependent manner with different potency in vitro. it was also noted that none of the sample tested showed any toxicity (liu & flynn, 2015) . several compounds isolated from p. corylifolia have many industrial applications and are available commercially. some of the examples are the following: the compound angelicin (cas 523-50-2) is available as antifungal compound (sardari, amin, sekhon, micetich, & daneshtalab, 2000) . the compound psoralen has been used as photochemical probe in studies of dna mutation and repair mechanisms (zarmouh, eyunni, & soliman, 2017) . methoxsalen (8-methoxypsoralen; cas 298-81-7) has been known as a potent suicide inhibitor of cytochrome p-450 (toyooka & ibuki, 2009 ). bakuchiol (cas 10309-37-2) is available as a ptp1b and dna polymerase inhibitor (choi et al., 2015) . bavachin (cas 19879-32-4 ) is available as a weak antioxidant that stimulates bone formation (jing et al., 2017) . corylifol c and, to a lesser extent, xanthoangelol are potent protein kinase inhibitors (inhibitory concentration 50% values for epidermal growth factor receptor; limper et al., 2013) . a well-known compound daidzin (cas 552-66-9) isolated from many plant species is a potent inhibitor of human mitochondrial aldehye dehydrogenase that demonstrates chemopreventitive activities (keung & vallee, 1993) . the compound genistein (cas 446-72-0) is available as a highly specific inhibitor of protein tyrosine kinase (zarmouh, messeha, elshami, & soliman, 2016) . these examples clearly show the importance of bioactive compounds isolated from p. corylifolia, an important traditional medicinal plant. the above-mentioned summary about p. corylifolia clearly showed that it is a very important plant from ethnobotanical, pharmacological, and chemical point of view. to date, more or less hundreds compounds have been separated from p. corylifolia, which was also mentioned by zhang et al., (2016) . we here presented the latest version of scientific literature on p. corylifolia, including the research work carried out in the recent years. p. corylifolia contains a wide variety of chemical constituents belonging to various groups, including flavonoids, coumarins, and meroterpenes, which are more dominant. p. corylifolia l. (fabacese) is a fortified source of biological active compounds, which gives the plant with great value for its use in pharmaceuticals, health, and body-care products. sehrawat and colleagues reported that p. corylifolia is a rare and endangered herbaceous medicinal plant. because most of the plant materials are collected from naturally occurring stands and are therefore being depleted rapidly and there is a possibility of extinction. therefore, it is suggested that there is a need for in vitro propagation of this species (sehrawat et al., 2014) . authors declare that there is no conflict of interest. anti microbial activity of different dosage forms of bakuchi (psoralea corylifolia linn.) taila, an ayurvedic formulation medicinal plants of bombay presidency efficacy of seed hydropriming with phytoextracts on plant growth promotion and antifungal activity in maize antipsoriatic microemulsion gel formulations for topical drug delivery of babchi oil (psoralea corylifolia) phytochemical studies and antimicrobial screening of non/less-polar fraction of psoralea corylifolia by using gc-ms psoralen photochemotherapy of cutaneous disorders compensatory effects of medicinal plants of pakistan upon prolongation of coagulation assays induced by naja naja karachiensis bite anti-venom potential of pakistani medicinal plants: inhibition of anticoagulation activity of naja naja karachiensis toxin biosynthesis of bakuchiol, a meroterpene from psoralea corylifolia medicinal and poisonous plants of pakistan genistein: a promising therapeutic agent for obesity and diabetes treatment systema naturae antibacterial activity of psoralea corylifolia l. seed and aerial parts with various extraction methods bakuchiol: a retinol-like functional compound, modulating multiple retinol and non-retinol targets new isoflavones and bioactive constituents from the fruits of psoralea corylifolia isobavachalcone and bavachinin from psoraleae fructus modulate aβ42 aggregation process through different mechanisms in vitro anti-tumor effects of bakuchiol, an analogue of resveratrol, on human lung adenocarcinoma a549 cell line bakuchiol: a hepatoprotective compound of psoralea corylifolia on tacrine-induced cytotoxicity in hep g2 cells prediction of drug-induced liver injury in hepg2 cells cultured with human liver microsomes psoralea corylifolia l. 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of psoralea corylifolia (somraji) and seed of trigonella foenum-graecum l.,(methi) in separate and composite manner in streptozotocin-induced diabetic male albino rat evaluation of a novel herbal formulation in the treatment of eczema with psoralea corylifolia ashtang ghrita: a noble ayurveda drug for central nervous system inhibitory effects of osthole, psoralen and aconitine on invasive activities of breast cancer mda-mb-231bo cell line and the mechanisms. zhong xi yi jie he xue bao= quality standards of indian medicinal plants corylinal: a new isoflavone from seeds of psoralea corylifolia phytochemical analysis of methanol extracts of psoralea corylifolia psoralidin induces autophagy through ros generation which inhibits the proliferation of human lung cancer a549 cells antimicrobial activity of leaf extract of psoralea corylifolia l the presence of three isoflavonoid compounds in psoralea corylifolia the pharmacology of chinese herbs neuroprotective effects of psoralea corylifolia linn seed extracts on mitochondrial dysfunction induced by 3-nitropropionic acid cytotoxicity of corylifoliae fructus. ii. cytotoxicity of bakuchiol and the analogues studies on lymphangiogenesis inhibitors from korean and japanese crude drugs induction of apoptosis in human hepatocarcinoma smmc-7721 cells in vitro by psoralen from psoralea corylifolia isobavachalcone attenuates mptp-induced parkinson's disease in mice by inhibition of microglial activation through nf-κb pathway medicinal plants. oxford and ibh publishing medicinal plants. tropical horticulture plant systematics: a phylogenetic approach aqueous extract of psoralea corylifolia l. inhibits lipopolysaccharideinduced endothelial-mesenchymal transition via downregulation of the nf-κb-snail signaling pathway handbook of ayurvedic medicinal plants: herbal reference library in vitro antimicrobial activities of bakuchiol against oral microorganisms. antimicrobial agents and chemotherapy daidzin: a potent, selective inhibitor of 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application of citrus hystrix as a folk remedy indian medicinal plants the wealth of india: raw materials: vol. viii. ph-re. the wealth of india: raw materials cytotoxicity of corylifoliae fructus. i. isolation of the effective compound and the cytotoxicity immunomodulatory and antitumour properties of psoralea corylifolia seeds two antifungal components isolated from fructus psoraleae and folium eucalypti globuli by bioassay-guided purification anti-dermatophytic activity of bakuchiol: in vitro mechanistic studies and in vivo tinea pedis-inhibiting activity in a guinea pig model isobavachalcone attenuates lipopolysaccharide-induced icam-1 expression in brain endothelial cells through blockade of toll-like receptor 4 signaling pathways phytoestrogen bakuchiol exhibits in vitro and in vivo anti-breast cancer effects by inducing s phase arrest and apoptosis osteoblasts proliferation and differentiation stimulating activities of the main components of fructus psoraleae corylifoliae fructus psoraleae contains natural compounds with potent inhibitory effects towards human carboxylesterase 2 bakuchiol contributes to the hepatotoxicity of psoralea corylifolia in rats estrogenic activities of psoralea corylifolia l. seed extracts and main constituents compounds isolated from psoralea corylifolia seeds inhibit protein kinase activity and induce apoptotic cell death in mammalian cells analysis of bakuchiol, psoralen and angelicin in crude drugs and commercial concentrated products of fructus psoraleae two new benzofuran derivatives, corylifonol and isocorylifonol from the seeds of psoralea corylifolia antiprotozoal screening of traditional medicinal plants: evaluation of crude extract of psoralea corylifolia against ichthyophthirius multifiliis in goldfish antimalarial activity of artemisia annua flavonoids from whole plants and cell cultures preparative isolation and purification of psoralen and isopsoralen from psoralea corylifolia by high-speed counter-current chromatography psoralidin, a coumestan analogue, as a novel potent estrogen receptor signaling molecule isolated from psoralea corylifolia cyp3a4 inhibition by psoralea corylifolia and its major components in human recombinant enzyme, differentiated human hepatoma huh-7 and heparg cells useful plants of the genus psoralea granzyme a cleaves a mitochondrial complex i protein to initiate caspaseindependent cell death the dangers of herbalism potential medicinal plants for lymphatic filariasis: a review natural sources used for treatment and prevention of filariasis bakuchiol inhibits the androgen induced-proliferation of prostate cancer cell line lncap through suppression of ar transcription activity effect of crude fractions of psoralea corylifolia seed extract on bone calcification effect of crude fractions of psoralea corylifolia seed extract on bone calcification in vitro enhancement of psoralen as an important anticancer compound in psoralea corylifolia through precursor feeding 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activity of extracts from psoralea corylifolia (fabaceae) correlated with the presence of a flavonoid compound potential antifilarial activity of the leaves and seeds extracts of psoralea corylifolia on cattle filarial parasite setaria cervi chemical fingerprint and quantitative analysis of fructus psoraleae by high-performance liquid chromatography mechanism of cytotoxicity by psoralea corylifolia extract in human breast carcinoma cells medicinal plants history, cultivation and uses studies on the chemical constituents of psoralea corylifolia l screening for inhibition activity of plant extracts on microorganism contaminating in cosmetics isolation and identification of furocoumarins from the seeds of psoralea corylifolia linn antifungal activity of diplotaenia damavandica antifungal potentiality of some plant extracts against fusarium sp plant-derived antimicrobial compounds: alternatives to antibiotics psoralea corylifolia l. an endangered medicinal plant with broad spectrum properties protective role of psoralea corylifolia l. seed extract against hepatic mitochondrial dysfunction induced by oxidative stress or aging comparison of the inhibitory potential of bavachalcone and corylin against udp-glucuronosyltransferases database on medicinal plants used in ayurveda agro-techniques of medicinal plants determination of isoflavone content and antioxidant activity in psoralea corylifolia l. callus cultures the effects of an antiosteoporosis herbal formula containing epimedii herba, ligustri lucidi fructus and psoraleae fructus on density and structure of rat long bones under tail-suspension, and its mechanisms of action optimization of elicitation condition with jasmonic acid, characterization and antimicrobial activity of psoralen from direct regenerated plants of psoralea corylifolia l systema naturae the netherlands in vitro acetylcholinesterase inhibition by psoralen using molecular docking and enzymatic studies in vitro and in vivo assessment of the effect of antiprotozoal compounds isolated from psoralea corylifolia against ichthyophthirius multifiliis in fish antifungal activity of phenyl derivative of pyranocoumarin from psoralea corylifolia l. seeds by inhibition of acetylation activity of trichothecene 3-o-acetyltransferase (tri101) pharmacognostic evaluation of the root of berberis asiatica fabaceae" angiosperm phylogeny website, 13 ed. missouri botanical garden and university of inhibition behavior of fructus psoraleae's ingredients towards human carboxylesterase 1 (hces1) dna polymerase and topoisomerase ii inhibitors from psoralea c orylifolia gonadal toxicity of an ethanol extract of psoralea corylifolia in a rat 90-day repeated dose study psoralen stimulates osteoblast differentiation through activation of bmp signaling review article: herbal hepatotoxicity-an update on traditional chinese medicine preparations new constituents from psoralea corylifolia histone deacetylase inhibitor sodium butyrate enhances the cell killing effect of psoralen plus uva by attenuating nucleotide excision repair psoralea corylifolia extract ameliorates experimental osteoporosis in ovariectomized rats screening south indian medicinal plants for antifungal activity against cutaneous pathogens osteoblastic proliferation stimulating activity of psoralea corylifolia extracts and two of its flavonoids chemical constituents from psoralea corylifolia and their antioxidant alphaglucosidase inhibitory and antimicrobial activities. zhongguo zhong yao za zhi= zhongguo zhongyao zazhi= chemical constituents from psoralea corylifolia and their antioxidant alphaglucosidase inhibitory and antimicrobial activities identification and characterization of naturally occurring inhibitors against udp-glucuronosyltransferase 1a1 in fructus psoraleae (bugu-zhi) indian medicinal plants. a compendium of 500 species positive skeletal effect of two ingredients of psoralea corylifolia l. on estrogen deficiency-induced osteoporosis and the possible mechanisms of action bioactive metabolites from the fruits of psoralea corylifolia effect of psoralen on bone formation bisbakuchiols a and b, novel dimeric meroterpenoids from psoralea corylifolia effects of gaultheria yunnanensis on adjuvant arthritis in rats. zhongguo zhong yao za zhi= zhongguo zhongyao zazhi= psoralen activates cartilaginous cellular functions of rat chondrocytes in vitro psc-afp, an antifungal protein with trypsin inhibitor activity from psoralea corylifolia seeds resveratrol induces the suppression of tumor-derived cd4+ cd25+ regulatory t cells the cytotoxicity of psoralidin from psoralea corylifolia the osteoprotective effect of psoralen in ovariectomy-induced osteoporotic rats via stimulating the osteoblastic differentiation from bone mesenchymal stem cells antidepressant-like effects of psoralidin isolated from the seeds of psoralea corylifolia in the forced swimming test in mice psoracorylifols a-e, five novel compounds with activity against helicobacter pylori from seeds of psoralea corylifolia antibacterial prenylflavone derivatives from psoralea corylifolia, and their structure-activity relationship study lipid class and fatty acid composition of psoralia corylifolia seed the benzopyrone biochanin-a as a reversible, competitive, and selective monoamine oxidase b inhibitor evaluation of the isoflavone genistein as reversible human monoamine oxidase-a and-b inhibitor. evidence-based complementary and alternative medicine the chemical constituents and bioactivities of psoralea corylifolia linn.: a review psoralea corylifolia l: ethnobotanical, biological, and chemical aspects: a review key: cord-330660-tx20im6w authors: mahmoud, huda k.; asghar, basim h.; harras, marwa f.; farghaly, thoraya a. title: nano-sized formazan analogues: synthesis, structure elucidation, antimicrobial activity and docking study for covid-19 date: 2020-10-07 journal: bioorg chem doi: 10.1016/j.bioorg.2020.104354 sha: doc_id: 330660 cord_uid: tx20im6w three series of nanosized-formazan analogues were synthesized from the reaction of dithiazone with various types of α-haloketones (ester and acetyl substituted hydrazonoyl chlorides and phenacyl bromides) in sodium ethoxide solution. the structure and the crystal size of the new synthesized derivatives were assured based on the spectral analyses, xrd and sem data. the antibacterial and antifungal activities were evaluated by agar diffusion technique. the results showed mild to moderate antibacterial activities and moderate to potent antifungal activities. significant antifungal activities were observed for four derivatives 3a, 3d, 5a and 5g on the pathogenic fungal strains; aspergillus flavus and candida albicans with inhibition zone ranging from 16 to 20 mm. molecular docking simulations of the synthesized compounds into leucyl-trna synthetase editing domain of candida albicans suggested that most formazan analogues can fit deeply forming stable complexes in the active site. furthermore, we utilized the docking approach to examine the potential of these compounds to inhibit sars-cov-2 3clpro. the results were very promising verifying these formazan analogues as a hopeful antiviral agents. according to world health organization (who) reports, the misuse of the antibiotics have led to development of multidrug resistance among various strains of microorganisms [1] . accordingly, new antimicrobial agents acting on novel targets have to be developed to overwhelm the increased incidence of microbial resistance to antibiotic remedy. from the best validated antimicrobial targets are the aminoacyl-trna synthetase enzymes which are key enzymes in the protein translation, producing the charged trnas required for proper assembly of peptide chains. from these enzymes, leurs have been considered as a drug target in fungi and bacteria, it is reported to be inhibited in the editing site by the potent antifungal 5-fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole (an2690) which is in clinical phases [2] [3] [4] . recently, the outbreak of covid-19, a new coronavirus pneumonia, caused by a new coronavirus (sars-cov-2) has emerged as a pandemic according to who in march 2020 [5] . to date, millions of infections and thousands of deaths have been recorded all over the world. in this scenario, there is a crucial need for developing antiviral agents interfering with the life cycle of the virus or with the virus replication or membrane fusion [6] . many researchers have considered the sars-cov-2 major protease (mpro), in addition called chymotrypsin-like protease (3clpr-2) as a potential target to anti-covid-19 drugs [7] [8] [9] . literature survey demonstrates that a lot of formazans have been described to possess broad spectrum of biological activities and pharmacological applications [10] such as antimicrobial [11] [12] [13] [14] , antiviral [15] [16] [17] , anticancer [18] , and anti-inflammatory [19] [20] . as for instance, the formazan derivative i was reported to display 100% inhibition of the ranikhet diseases virus [21] . additionally, the two formazans ii and iii synthesized by misra and dhar [22] showed 87% and 83% protections against the ranikhet disease virus, respectively. furthermore, many formazans iv were reported by lakshmi et al. [23] to have significant antibacterial and antifungal activities. also, uraz et al. [24] synthesized some formazan derivatives v, vi with different substituents and evaluated their antibacterial and antifungal activities against some selected microorganism species. the results revealed high activity against c. tropicalis, c. kefir, s. cerevisiae and c. neofarmans (figure 1) . recently, the synthesized drugs in the nanoscale have demonstrated a superior ability to penetrate the dna of various diseases, which have increased their biological activity and their ability to inhibit the diseases [25, 26] . inspired by the promising previously reported antimicrobial and antiviral activities of formazans and the urgent need of new effective antimicrobial agent and antiviral drugs to act mainly against covid-19 and in continuation of our research work in synthesis of bioactive compounds [27] [28] [29] [30] [31] [32] , we synthesized herein a new series of nano-sized formazan analogues to study their potential as antibacterial and antifungal agents in vitro. additionally, molecular docking simulations were done to propose their mode of binding in the editing domain of leurs and to show the possibility of these compounds to act against sars-cov-2 main protease enzyme. the first series of formazan analogues 3a-f were synthesized in sodium ethoxide solution at the xrd diffraction is a good tool to predict the size of the solid sample and the degree crystal regularity. five sample 3d, 3f, 5g, 5h and 7b of the synthesized formazan analogues were screened over 10˚<2θ <80˚ range to determined their crystallographic features (figures 6a-e). all investigated formazan analogues revealed sharp peaks which indicated the crystalline feature of them. the size of the crystals of the five samples was calculated according to the reported debye-scherrer equation [33] and the calculated size was tabulated in table 1 . the results referred to the formazan analogues moieties synthesized in the nanometer-scale. in addition, sem is another tool useful to give excellent insight about the crystallinity as well as surface topography for the tested solid samples. figure 7 contains two sem images for two formazan analogues 5h and 7b as examples for the prepared series. the two images indicated that the crystals of the two derivatives are found in the nanometer-scale. antimicrobial activities were carried out at the regional center for mycology and biotechnology (rcmb), al-azhar university, cairo, egypt. target compounds 3a-e, 5a-h, 7b were evaluated for their in vitro antibacterial, and antifungal activities, by inhibition zone method against two gram-positive bacteria: staphylococcus aureus (rcmb 010010) and bacillus subtilis (rcmb 015), two gram-negative bacteria: escherichia coli (rcmb 010052) and proteus vulgaris (rcmb 004) and two fungi: aspergillus flavus (rcmb 002002) and candida albicans (rcmb 005003) using gentamycin and ketoconazole as reference antibacterial and antifungal drugs, respectively (table 2&3 ). concerning the antibacterial activity against gram-positive bacteria, most compounds showed mild to moderate activities. the best activities were seen for the acetyl derivatives 5a, 5b, 5c, 5g and 5h with inhibition zones values ranging from 15 to 18 mm, compared to gentamycin with iz = 24 and 26 mm for s. aureus and b. subtilis, respectively. regarding gram-negative bacteria, they were resistant to 3a and 3b, while 3d having 4-br group revealed moderate activity against p. vulgaris (iz=17 mm) compared to gentamycin (iz=25 mm). on the other hand, compounds 5a, 5b, 5g and 5h displayed reasonable antibacterial activities against p. vulgaris with iz values 16, 18, 17 and 18, respectively. additionally, most compounds revealed mild antibacterial activities against the gram negative e. coli. most of the tested formazan analogues exhibited promising antifungal activities with the exception of 3e, 5f and 7b that were inactive against used fungal strains. focusing on the antifungal activities of compounds 3a-e, compound 3a elicited comparable antifungal activity (iz= 17 and 18 mm against a. flavus and c. albicans, respectively) to ketoconazole (iz= 16 and 20 mm against a. flavus and c. albicans, respectively). also, significant activities were observed for compounds 3b and 3c (iz=13-16 mm). in addition, compound 3d demonstrated superior antifungal activity against a. flavus (z= 20 mm) that was more potent than ketoconazole. furthermore, by studying the antifungal activities of 5a-h, moderate to potent activities were displayed. among these compounds, compound 5g with 3-cl group showed iz= 20 mm against a. flavus and 18 mm against c. albicans that were higher than those of ketoconazole. additionally, compound 5a showed comparble activity (iz= 16 and 19 mm) to ketoconazole. these antifungal activities results were highly appreciated since a. fumigatus is the second main cause of invasive aspergillosis and is the first leading cause of cutaneous aspergillosis [34] . in addition to the increased incidence of infections by c. albicans, the most common cause of candidiasis, and the increased resistance of c. albicans to antifungal drugs [35, 36] . leucyl-trna synthetase (leurs) belongs to the family aminoacyl trna synthetases (aarss), group of central enzymes that play a crucial role in protein synthesis, which is vital for survival of micro-organism and hence its inhibition presented a novel and attractive target for developing antimicrobials [37] . many recent reviews have discussed the importance of aarss in the discovery and development of antibacterial and antifungal agents [38] [39] [40] [41] . in this study, molecular docking study of the newly synthesized formazan analogues 3a-f, 5a-h and 7a,b have been performed onto the active site of candida albicans editing domain of cytosolic leucyl-trna synthetase to demonstrate their binding affinity and orientation. results of the docking simulation were displayed in table 4 showing the docking scores and the different formed interactions such as hydrogen bond, pi-h and non-polar pi-cation interactions. for majority of compounds, ala315, lys407, and lys483 were recognized as key amino acid residues responsible for hydrogen bonds generation and thr316, leu317, arg318, asp421and tyr487 were identified for minor interaction. whereas, for pi-h and pi-cation interactions, lys407, ser419, lys483 and tyr487 were the only observed residues. focusing on the binding mode of the most active analogues as antifungals, 3a, 3d, 5a and 5g (figure 8) , it was observed that they are well stabilized into the active site through strong it an attractive target for developing anti-coronavirus drug [42] . the protein structure of 3clpro-2 consists of 9 α-helices and 13 β-strands making together three distinctive domains: domain i (residues 8-101), domain ii (residues 102-184) and domain iii (residues 201-306) connected to domain ii by an extended loop (residues 185-200). 3clpro-2 contains a catalytic dyad that is composed of conserved residues his41 and cys145 and the key substrate-binding site is formed as a split between domain i and domain ii [43] . to estimate the binding affinity of derivatives 3a-f, 5a-h and 7a,b with covid-19 3clpro (pdb code: 6lu7), molecular docking study was done. as shown in table 5 and gln189 indicating the importance of these hydrophobic moieties. molecular modeling study revealed that these compounds could bind properly to c. albicans leucyl-trna synthetase editing domain. additionally, docking simulation into the active site of covid-19 3cl protease showed superior fitting into the active site with binding scores from -5.6064 to -8.0555 kcal/mol. the melting points of all new formazan analogues were recorded using a smp3 melting all the microbial strains that used in the current study have been supplied from al-azhar university in cairo, egypt from the culture collection of the regional center for mycology and biotechnology (rcmb). the method used for recording the antimicrobial activity according to the literature method [44] . molecular docking was analyzed through using moe-dock 2014 software [45] . chemical structures of 3a-f, 5a-h and 7a,b were drawn by the moe builder followed by minimization using the force field mmff94x in this program. hydrogen atoms were then added and unwanted water molecules were cancelled. docking was then performed using london dg for rescoring 1 and gbvi/wsa dg for rescoring 2. at the same time, refinement was done through forcefield. "ligand interactions" was utilized for the 2d visualization o the proteinligand interactions. the best pose was then selected depending on the binding energy and the interactions found in the active site. cm -1 . 1 h nmr (dmso-d 6 ) 1.60 (s, 3h anal. calcd. for c 22 h 19 cln 6 os (450.94) calcd: c, 58 -nitrophenyl)-2-oxopropanehydrazonic-n',2-diphenyldiazenecarbohydrazonic thioanhydride (5e) ir ύ: 3479 (br. 2nh), 1662 (co), 1596 (c=n) ir ύ: 3436 (br 2nh), 1653 (co), 1594 (c=n) -chlorophenyl)-2-oxopropanehydrazonic-n',2-diphenyldiazenecarbohydrazonic thioanhydride (5g) orange solid, yield (0.38g, 85%), mp 160-162°с (ethanol /dioxane), ir ύ: 3437 (br 2nh), 1659 (co), 1593 (c=n) m/z (%) 452 (m + +2, 0.16), 451 (m + +1, 0.11), 450 (m + , 0.38) aminoacyl-trna synthetases as drug targets in eukaryotic parasites an antifungal agent inhibits an aminoacyl-trna synthetase by trapping trna in the editing site crystal structures of the human and fungal cytosolic leucyl-trna synthetase editing domains: a structural basis for the rational design of antifungal benzoxaboroles molecular investigation of sars-cov-2 proteins and their interactions with antiviral drugs putative inhibitors of sars-cov-2 main protease from a library of marine natural products: a virtual screening and molecular modeling study molecular docking reveals the potential of aliskiren, dipyridamole, mopidamol, rosuvastatin, rolitetracycline and metamizole to inhibit covid-19 virus main protease tmprss2 and is blocked by a clinically proven protease inhibitor functionalized formazans: a review on recent progress in their pharmacological activities synthesis, evaluation and docking studies of novel formazan derivatives as an enoyl-acp reductase inhibitors synthesis and evaluation of antimicrobial activity of some new schiff bases and formazans synthesis, characeterization and in vitro antibacterial activity of novel 3-(4-methoxyphenyl)-1-isonicotinoyl-5-(substituted phenyl)-formazans synthesis and biological studies of some novel formazans synthesis of some new formazans as potential antiviral agents synthesis and antiviral activity of some new formazans synthesis of 1-(20aryl-40-oxo-3hquinazolyl)-3-aryl-5-phenyl-formazans as potential anti-viral agents synthesis of some new formazans and their biological activity novel formazans as potent anti-inflammatory and analgesic agents antiinflammatory activity of quinazolinoformazans synthesis of some newer formazans and tetrazolium salts as antiviral agents synthesis of some newer formazans and tetrazolium salts and their effect on ranikhet disease virus and the vaccinia virus synthesis and their possible biological activities of few formazans of 3-amino-2-sulphanyl-2 discovery of thiazole-based-chalcones and 4-hetarylthiazoles as potent anticancer agents: synthesis, docking study and anticancer activity new azoloazine derivatives as antimicrobial agents: synthesis under microwave irradiations, structure elucidation, and antimicrobial activity new series of thiazole derivatives: synthesis, structural elucidation, antimicrobial activity, molecular modeling and moe docking zno nanoparticles catalyst in synthesis of bioactive fused pyrimidines as anti-breast cancer agents targeting vegfr-2 antitumor activity of pyrrolizines and their cu(ii) complexes: design, synthesis and cytotoxic screening with potential apoptosis-inducing activity new and efficient approach for synthesis of novel bioactive [1,3,4]thiadiazoles incorporated with 1,3-thiazole moiety elements of x-ray diffraction aspergillus flavus: human pathogen, allergen and mycotoxin producer mechanisms of pathogenic candida species to evade the host complement attack pathogenicity and drug resistance in candida albicans and other yeast species hybrid phenylthiazole and 1,3,5-triazine target cytosolic leucyl-trna synthetase for antifungal action as revealed by molecular docking studies aminoacyl-trna synthetases and their inhibitors as a novel family of antibiotics aminoacyl-trna synthetases: essential and still promising targets for new anti-infective agents aminoacyl-trna synthetase inhibitors as potential antibiotics aminoacyl-trna synthetase inhibitors as potent antibacterials molecular investigation of sars-cov-2 proteins and their interactions with antiviral drugs anti-hiv drug repurposing against sars-cov-2 molecular operating environment (moe) 2014.09, chemical computing group inc., 1010 sherbrooke street west, suite 910 ☒ the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work ☐the authors declare the following financial interests/personal relationships which may be considered as potential competing interests: _______________________________________________________________________________ ______ nano-sized formazan analogues: synthesis, structure elucidation, antimicrobial activity and docking study for harras and thoraya a. farghaly a,b * key: cord-286136-gm6w590s authors: aleksic sabo, verica; knezevic, petar title: antimicrobial activity of eucalyptus camaldulensis dehn. plant extracts and essential oils: a review date: 2019-03-05 journal: ind crops prod doi: 10.1016/j.indcrop.2019.02.051 sha: doc_id: 286136 cord_uid: gm6w590s eucalyptus has become one of the world’s most widely planted genera and e. camaldulensis (the river red gum) is a plantation species in many parts of the world. the plant traditional medical application indicates great antimicrobial properties, so e. camaldulensis essential oils and plant extracts have been widely examined. essential oil of e. camaldulensis is active against many gram positive (0.07–1.1%) and gram negative bacteria (0.01–3.2%). the antibacterial effect is confirmed for bark and leaf extracts (conc. from 0.08 μg/ml to 200 mg/ml), with significant variations depending on extraction procedure. eucalyptus camaldulensis essential oil and extracts are among the most active against bacteria when compared with those from other species of genus eucalyptus. the most fungal model organisms are sensitive to 0.125–1.0% of e. camaldulensis essential oil. the extracts are active against c. albicans (0.2–200 mg/ml leaf extracts and 0.5 mg/ml bark extracts), and against various dermatophytes. of particular importance is considerable the extracts’ antiviral activity against animal and human viruses (0.1–50 μg/ml). although the antiprotozoal activity of e. camaldulensis essential oil and extracts is in the order of magnitude of concentration several hundred mg/ml, it is considerable when taking into account current therapy cost, toxicity, and protozoal growing resistance. some studies show that essential oils’ and extracts’ antimicrobial activity can be further potentiated in combinations with antibiotics (beta-lactams, fluorochinolones, aminoglycosides, polymyxins), antivirals (acyclovir), and extracts of other plants (e.g. annona senegalensis; psidium guajava). the present data confirm the river red gum considerable antimicrobial properties, which should be further examined with particular attention to the mechanisms of antimicrobial activity. the continuing increase in the degree of bacterial resistance to conventional antibiotics is a problem of global significance. the crisis of antimicrobial resistance has been ascribed to the misuse of these agents and today resistant strains are common, such as methicillin-resistant staphylococcus aureus, vancomycin-resistant enterococci, drug resistant streptococcus pneumoniae and mycobacterium tuberculosis, carbapenemresistant and extended-spectrum beta-lactamase producing enterobacteria, multidrug-resistant pseudomonas aeruginosa and acientobacter baumannii etc. it was estimated that the medical cost per patient with an antibiotic-resistant infection is up to $29,069 and infections are usually life treating (ventola, 2018; aslam et al., 2018) . similarly, fungi have become resistant to poliens, azoles and echinocandins, and the emergence of drug-resistant strains has been reported in all fungal species (robbins et al., 2017) . beside the noticeable emergence of resistant protozoa and viruses, there is a problem with camaldulensis is highly variable (table 1 ). in the past, this character has been used to break up the group into different varieties or subspecies. the entire complex is currently under revision and new varieties or subspecies may be described or extant ones rationalised. until this work is completed, euclid (2006) decided to adopt a conservative view of e. camaldulensis. used for centuries as a traditional aboriginal herbal remedy, eucalyptus leaves and their essential oils have found various applications in everyday life due to their antiseptic, anti-inflammatory and antipyretic properties (jeane et al., 2003; kumar et al., 1988) . ancient aboriginal society in australia used e. camaldulensis plant in medicines to treat gastrointestinal symptoms (including colic, diarrhea, and dysentery), respiratory disease (colds, coughs, asthma, laryngalgia, laryngitis, pharyngitis, sore throat, trachalgia), arrest bleeding, open wounds, and cuts, as well as its decoctions for the relief of spasms, aches, and pains in muscles, but also pains in joints and even tooth (duke and wain, 1981) . as previously stated, e. camaldulensis plant is also known as red gum eucalyptus, murray red gum, and river red gum, because it produces red kino i.e. red gum, in significant amount. thus besides different plant parts aborigines used its secondary products as folk remedies. they made incisions in the tree trunks for obtaining the red kino and applied it directly to abrasions and cuts. except fresh kino, the dried, dehydrated kino was prepared and used in the same way as fresh, but after softening in water (williams, 2011; clarke, 2014) . another significant folk remedy is young leaves which were used for smoke bath, where burning leaves smoke surrounds patient. the smoking medicine was used for fevers, colds, flu and general sickness (williams, 2011; pennacchio et al., 2010; duke and wain, 1981) . being useful for treating various health conditions, e. camaldulensis and its folk remedies then were transferred and introduced to other parts of the world, such as africa. in sudan the red kino was used for sore throat and diarrhea, while the smoke of burnt leaves was inhaled in case of respiratory problems. in senegal for stomach-ache decoctions from leaves were prepared with sugar, while in zimbabwe for cough, flu, and fever a decoction of e. camaldulensis leaves were combined with citrus limon (l.) burm. f. fruits and psidium guajava l. leaves (doran and wongkaev, 2008; maroyi, 2013) . further more, to prevent tooth decay and periodontitis in nigeria teeth cleaning sticks were made from tree (bukar et al., 2004) , and in traditional medicine for healing wound infections, poultice of leaves containing eucalyptus oil have been used (adeniyi et al., 2006) . nowdays, e. camaldulensis has been the subject of numerous studies, to confirm plant's usefulness in traditional medicine for the treatment v. aleksic sabo and p. knezevic industrial crops & products 132 (2019) [413] [414] [415] [416] [417] [418] [419] [420] [421] [422] [423] [424] [425] [426] [427] [428] [429] of various ailments (coelho-de-souza et al., 2005; ghani, 2003; ito et al., 2000) . its essential oils are reported to be anesthetic, antiseptic and astringent (jeane et al., 2003; kumar et al., 1988) . in addition, a decoction of the leaves is reported to be a remedy for sore throat and other bacterial infections of the respiratory and urinary tracts (bruneton, 1999) . due to numerous contemporary data regarding the antimicrobial activity of e. camaldulensis, this subject will be discussed in special section/chapter. except antimicrobial effects, e. camaldulensis plant extracts (pex) and essential oils (eos) and its constituents possess numerous other beneficial effects. one such effect is certainly gastrointestinal effect. in animal models, extracts of the leaves of e. camaldulensis and e. torelliana r. muell are reported to decrease gastric acid production and thus appear useful for the treatment of gastric ulcers (adeniyi et al., 2006) . it has been proven that e. camaldulensis leaves methanol extracts possessed ulcer-healing promoting effect when investigated in acetic acid induced-ulcer in rat (rattus norvegicus domesticus) (table 2) . similarly, the poultice of the leaves is applied over wounds and ulcers (gill, 1992) . the antioxidant effect represents one more useful e. camaldulensis characteristic. the free radical scavenging activities of the essential oils is assessed by measuring their scavenging abilities for 2,2-diphenyl-1picrylhydrazyl (dpph) radicals. the scavenging activity for the eucalyptus camaldulensis was characterized as high (81.9%) (ghaffar et al., 2015) . the results of e. camaldulensis eo antioxidant effect evaluation indicated that the eo had high potent ferrous ions chelating and total antioxidant activities comparing to ascorbic acid and bht (el-baz et al., 2015) . also, the e. camaldulensis var. brevirostris leaves ethanol extract possessed antioxidant activity, where the prevailing antioxidants in the extract were gallic and ellagic acid (el-ghorab et al., 2003) . there are several more studies dealing with antioxidant activity of e. camaldulensis (barra et al., 2010; salem et al., 2015; siramon and ohtani, 2007; olawore and ololade, 2017) , but it is interesting to mention here that e. camaldulensis flower eo inhibited melanogenesis through its antioxidant properties and by down-regulating both mitogen-activated protein kinases (mapk) and protein kinase a (pka) signaling pathways. this study indicated that the essential oil has the potential to be developed into a skin care product (huang et al., 2015) . thus, except the medical application, e. camaldulensis extracts are also currently used in cosmetic formulations, and leaf extracts have been approved as food additives (takahashi et al., 2004) . also, essential oils and their constituents have been used as flavoring agents in the formulation of different pharmaceutical products, cosmetics, and food industry (cowan, 1999) . except this, e. camaldulensis pex and eos have the potential to be used as antibacterial and antifungal agents in cosmetic and pharmaceutical products. it is interesting to mention here the activity of e. camaldulensis eos (2-8 mg/ml) on dental biofilm formation in vivo where detected inhibition was 14.5-39.2% after four weeks, comparing to chlorhexidine (2 mg/ml), which inhibited maximum 13.9% of dental biofilm formation . extracts and essential oils of this aromatic plant can be used as food preservatives in order to reduce the dependency on synthetic chemicals in food preservation. in australia, it is also used as sources of wild honey, providing bees with good quality pollens and heavy yields of nectar (boland et al., 1984) . moreover, in industry, the wood of e. camaldulensis has been used for heavy construction, railway sleepers, flooring, framing, fencing, plywood, and veneer manufacture, wood turning, firewood, and charcoal production (boland et al., 1984) . eucalyptus camaldulensis wood burns well and make a good fuel, also its dense wood and coppicing ability make it an excellent species for fuelwood production used in several countries such as brazil (jacobs, 1981; eldridge et al., 1993) . furthermore, eucalyptus biomass residues from agro-forest and pulping industries represent a valuable source of highvalue compounds such as triterpenic compounds (domingues et al., 2011; ferreira et al., 2018) . due to the diversity of e. camaldulensis beneficial effects, all effects reported in the literature are summarized in table 2 . beside the beneficial effects, essential oils and plant extracts can exert potentially unfavorable effects as complex mixtures of different compounds. a risk assessment of their hazard is always necessary before commercialization, so the estimation of eos toxicity has been already conducted resulting in human oral and dermal dose limit recommendations. for most eos the recommended dose is in range 1-4%, but for cineole-rich eucalyptus sp. eos, including e. camaldulensis, the limit dose is 10%, indicating a generally low application risk (lis-balchin, 2006) . the safe daily oral dose in human adults is 300-600 mg, while semisolid preparations for topical use may contain 5-20% of eucalyptus oil (blumenthal and busse, 1998; tisserand and young, 2014) . similarly, e. camaldulensis bark methanolic extract ld50 value for swiss albino mice (mus musculus) is very high -1120 mg/kg, indicating its low host toxic effects (islam et al., 2014) . the low toxicity and natural origin of e. camaldulensis essential oil and extracts, in contrast to synthetic antimicrobials, favor their application as antimicrobial agents. eucalyptus camaldulensis leaves contain 0.1-0.4% essential oil, of which 77% is 1,8-cineole. there is considerable amount of cuminal, phellandrene, aromadendren (or aromadendral), valerylaldehyde, geraniol, cymene, and phellandral (council of scientific and industrial research, 1948 -1976council of scientific and industrial research (s.i.r, 1948council of scientific and industrial research, 1948 -1976 slee et al., 2006) . leaves contain 5-11% tannin. the kino (a class of wood exudates), contains 45% kinotannic acid as well as kino red, a ebrahimi et al. (2013) repellency against the adult females of culex pipiens dried fruits essential oil two different treatment levels (5 and 10 μl) in six exposure times (15, 75, 135, 195 , 255 and 315 s) erler et al. (2006) anti-diabetic effect albino rats oral 500 mg/kg of body weight dawoud (2015) alloxan-induced diabetic rats leaves ethanol extract 500 mg/kg of body weight in distilled water orally, e. camaldulensis leaves supplement incorporated into the diet 5 g/kg/day dawoud and shayoub (2017) v. aleksic sabo and p. knezevic industrial crops & products 132 (2019) 413-429 glucoside, catechol, and pyrocatechol. leaves and fruits test positive for flavonoids and sterols. the bark contains 2.5-16% tannin, the wood 2-14%, and the kino 46.2-76.7% (watt and breyer-brandwijk, 1962) . some of the reported phytoconstituents of the tree included essential oils, sterols, alkaloids, glycosides, flavonoids, tannins, and phenols. a considerable variation in the yield of leaf essential oil from e. camaldulensis has been reported (boland et al., 1984; shieh, 1996; moudachirou et al., 1999; farah et al., 2002) , depending on multiple biotope factors, and also genetic and/or epigenetic characteristics of the plant. the yields of e. camaldulensis leaves eo (0.90-0.98%) originating from pakistan and morocco were similar (ashraf et al., 2010; farah et al., 2002) , while moudachirou et al. (1999) reported a variable oil content of 0.6-1.4% from different locations of benin. the oil yield of e. camaldulensis from jerusalem was 0.5% (chalchat et al., 2000) and significantly higher oil yield was reported for e. camaldulensis from taiwan: 2.3-3.0% with respect to different seasons (shieh, 1996) . similar eos yield (0.77-2.53%) has been reported for e. globulus, as one of the economically important plants for essential oil production (joshi, 2012; selvakumar et al., 2012; harkat-madouri et al., 2015) . the reported essential oil yield for other eucalyptus species is slightly higher, ranging from 1.2% to 3% (w/w): the highest yield was obtained from e. cinerea f. (sebei et al., 2015) . all the e. camaldulensis essential oil single compounds belong to chemical class of hydrocarbons terpenes, further devided according to the number of isoprene units (c 5 h 8 ) to monoterepenes (c 10 h 16 ), sesquterepenes (c 15 h 24 ), and longer chains of isoprene units. oxygenated terpenes (oxygenated monoterepenes and oxygenated sesquterepenes) are called trepenoids. according to the literature, in e. camaldulensis eos dominates 1,8-cineole (eucalyptol), trans-pinocarveol and terpinen-4-ol from chemical class of oxygenated monoterepenes. the oils also contain considerable amount of monoterpene hydrocarbons (β-pinene, α-thujene, γ-terpinene, p-cymene), while sesquterepene hydrocarbons and oxygenated sesquterepenes are detected in significantly lower amounts (table 3) . when the composition of five eucalyptus essential oils (eucalyptus camaldulensis, eucalyptus astringens maiden, eucalyptus leucoxylon, eucalyptus lehmannii and eucalyptus rudis endl) are compared, a high percentage of monoterpenes, mainly oxygenated compounds, with lower quantities of sesquiterpenes were recorded throughout the four seasons (ben jemaa et al., 2012) . in e. camaldulensis oil, monoterpenes were prevalent (34.6-56.3% for all seasons) while sesquiterpene hydrocarbons (6.6-16.5%) and oxygenated sesquiterpenes (2.1-11.1%) were present in less extent. eucalyptus astringens oil had resembling chemical characteristic to e. camaldulensis oil, the abundant quantity of monoterpenes, which represented more than 50% of the total oil amounts for the all seasons (53.4-63.6 %). similarlly, e. leucoxylon essential oil, contained mainly oxygenated monoterpenes with a prevalence of 1,8 cineole (13.1-17.6%), such as in e. camaldulensis oil (15.5-20.6%). the essential oil of e. lehmannii also was made up largely of monoterpenes (hydrocarbons 27.6-44.9% and oxygenated 30.9-62.8%), with smaller amounts of sesquiterpene hydrocarbons and absence of oxygenated sesquiterpenes, unlike the oils of other eucalyptus species (ben jemaa et al., 2012) . the difference in the chemical composition of the e. camaldulensis eos may be due to many reasons, which can generally be classified in five main groups: (1) the change in plant genes through generations and hybridizations (naturally and induced) may result in production a variety of volatile oils compared with those of different habitat; (2) nutrients of different soils and their accumulation in the leaves may result in different plant metabolism and consequently production of different bio-products and also eos made of diverse compounds in variable amounts; (3) acclimation of species to the australian environment in which it is growing in the past, compared with the introduced and/or worldwide planted trees on plantations; (4) different ecotypes of the e. camaldulensis and (5) differences may be due to plant part used for essential oils extraction and its stage of development (maturity). knowing that these factors express significant effect on the percent compositions of some eo components for this species, e. camaldulensis can be grown in the corresponding areas and in specific conditions to enhance eo production. the variations in the chemical composition of eucalyptus eos with respect to seasons have also been reported (tsiri et al., 2003) , but the most commonly detected as major components in the eucalyptus essential oil are 1,8-cineole, β-pinene, γ-terpinene, and p-cymene. it is important to emphasize here that according to chemical composition the eucalyptus camaldulensis eo generally can be divided in two different types. type i is a cineole-rich essential oil containing 80-90% 1,8-cineole plus pinene, and type ii is a cineole-poor essential oil, containing significantly less cineol (williams, 2011) . plant genotype is important factor influencing the final chemical composition of eo (djilani and dicko, 2012) . due to genetic and epigenetic factors same plant species can produce a similar eo, but with different chemical composition and therapeutic activities. brophy and southwell (2002) examined essential oils of two variations, eucalyptus camaledulensis var. camaldulensis and eucalyptus camaledulensis var. obtuse, and the main compounds of eucalyptus camaledulensis var. camaldulensis were pcymene (22%), cryptone (14%), and spathulenol (17%), while eucalyptus camaledulensis var. obtusa had different main compounds: 1,8cinole (52%), α-pinene (15%), and aromadendrene (3%), suggesting that these subspecies belong to different types of eucalyptus essential oils. the content of 1,8-cineole was also variable but in the same range for essential oils reported from greece (25.3-44.2%) (tsiri et al., 2003) , pakistan (34.4-40.0%) (ashraf et al., 2010) , mozambique (37.1-40.0%) (pegula et al., 2000) , nigeria (32.8-70.4%) (oyedeji et al., 1999) , and taiwan (34.0-68.2%) (shieh, 1996) . similarly, the major component of eucalyptus camaldulensis oils originating form burundi, morocco, and benin was 1,8-cineole ranging from 31.0 to 72.5% with no presence of cryptone (dethier et al., 1994; zrira and benjilali, 1991; zrira et al., 1992; moudachirou et al., 1999) . cryptone has been shown to be present in low-cineole varieties of eos from australia (bignell et al., 1996) , uruguay (dellacassa et al., 1990) and south florida (pappas and sheppard-hanger, 2000) . for example, the major constituents identified in the essential oil from south florida included p-cymene (35.0%), cryptone (13.7%), terpinen-4-ol (5.7%), spathulenol (4.3%), and cuminaldehyde (3.7%), with a very low amount of 1,8-cineole (2.7%) (pappas and sheppard-hanger, 2000) . it was proven that essential oils of different plant parts have different chemical composition (table 3) . previous studies on the essential oil of e. camaldulensis flowers revealed the presence of 1,8-cineole, βpinene, and spathulenol as the most abundant constituents (giamakis et al., 2001) . the essential oil of the leaves was found to contain pcymene, γ-terpinene, α-pinene, 1,8-cineole, terpinen-4-ol, α-terpineol, carvacrol, and thymol as the major components (siramon and ohtani, 2007) . the major components of the fruits essential oil were aromadendrene, α-pinene, drimenol, and cubenol (el-ghorab et al., 2002) . plant developmental stage and maturity of plant parts used for essential oil extraction also affect essential oil chemical composition. giamakis et al. (2001) analyzed the immature flowers and calli grown in athens (greece), and they found that the main monoterpenes produced in e. camaldulensis calli, cultured in darkness and under light conditions, were 1,8-cineole, 62.70 and 69.26% as well as β-pinene, 27.09 and 25.31%, respectively. in lower amounts α-pinene (1.2 and 1.1%, respectively) and the terpenoids, camphene, myrcene, isocineole, myrtenol, bicyclogermacrene, spathulenol, and trans-pinocarveol were present (less than 1%). apart from isocineole, these constituents were also determined in the essential oil from immature flowers. this is remarkable because giamakis et al. (2001) showed that undifferentiated calli are capable of producing high amounts of monoterpenoid compounds (approx. one third of that produced by the explant). this makes immature flowers from e. camaldulensis an interesting candidate for the development of calli able to produce high percentages of these two important monoterpenes, 1,8-cineole and β-pinene (giamakis et al., 2001) . also, the influence of light conditions on essential oil chemical composition showed that light conditions did not considerably affect the production of monoterpenes and sesquiterpenes compounds by calli developed from immature flowers (giamakis et al., 2001) . furthermore, plant culture conditions can influence the essential oil chemical composition. soil salinity is a key ecological stress that severely influences plant productivity (williams, 2011) . ashraf et al. (2010) showed that salinity had a considerable effect on the percent compositions of some components of e. camaldulensis leaves essential oil. the mean values of 1,8-cineole content of eo from saline and nonsaline provenances of pakistan were 34.42 and 40.05%, respectively (ashraf et al., 2010) . therefore, they recommend stressing of this species by growing in the saline areas to enhance essential oil production for its various medicinal and pharmacological uses. extraction represents the primary step in obtaining the crude mixture of compounds from plants. quality and quantity of the extracts dependent of the target compound structures, natural sources, and type of processes (karacabey et al., 2013) , explaining the different phenolic composition in the extracts obtained with different procedures. the most commonly plant extract have been obtained by conventional solvent extraction methods (infusion, decoction, digestion, maceration, and percolation) (azwanida, 2015) using solvents such as water, ethanol, methanol, chloroform, dimethyl-sulfoxide etc. however, these techniques are demanding regarding the extraction process duration, organic solvent consumption, and lack of extraction automation. the potential and powerful alternative to conventional liquid solvent extraction methods are ultrasonic-assisted extraction (uae) and microwave-assisted extraction (mae), especially in the case of plant material (hao et al., 2002; eskilsson and bjrklund, 2000) . interest in mae has increased significantly over the past 5-10 years in particular medicinal plant research, as a result of its inherent advantages as special heating mechanism, moderate capital cost, and its good performance under atmospheric conditions (ballard et al., 2010; chan et al., 2011) . in addition, mae technique possesses many advantages compared with other methods for the extraction of compounds such as bioactive compounds (sanchez-aldana et al., 2013) saving in processing time and solvent, higher extraction rate, better products with lower cost, reduced energy consumption (up to 85-fold savings), and waste generation (yan et al., 2010; yemis and mazza, 2012) . this is confirmed for e. camaldulensis extraction of phenolic and flavonoid compounds, where the compounds were extracted with mae for 5 min which was equivalent with uae (60 min) and traditional extraction (24 h) methods (gharekhani et al., 2012) . many authors reported the chemical composition of e. camaldulensis extracts. the leaves of e. camaldulensis from the zoo-botanical garden in giza (egypt) yielded 4 major fractions (singab et al., 2011) . the major components of the first fraction (eluted with water) were identified as hhdp-glucopyranose, chlorogenic acid, and phloroglucinol derivatives. the second 30% methanol fraction was found to contain different galloyl-hhdp-glucopyranose positional isomers and pedunculagin as major components. the third 60% methanol fraction was predominantly composed of digalloyl-hhdp-glucopyranose (tellimagrandin i) α and β anomers, while the last 100% methanol fraction was composed of a mixture of ellagitannin dimers. the profiling of the obtained fractions by hplc-pda-esi/ms/ms indicated that ellagitannins were the most predominant components of all three methanol fractions (singab et al., 2011) . the secondary metabolites screening of e. camaldulensis leaf extracts from nigeria confirmed presence of tannin, saponins, and cardiac glycosides (ayepola and adeniyi, 2008) . analyzed n-hexane, chloroform, and methanol extracts of e. camaldulensis stem bark and leaf also grown in nigeria showed the presence of tannins and saponins in the stem bark and in the leaf of e. camaldulensis with absence of alkaloids in all extracts (adeniyi et al., 2009) . furthermore, the crude methanol leaf extracts also from nigeria contained in addition volatile oils and balsam (gum) (babayi et al., 2004) . similarly, the phytochemical screening of ethanol, methanol, and petroleum ether leaf extracts from nigeria contained in moderate to high amount secondary metabolites: alkaloids, saponins, tannins, flavonoids, steroid, carbohydrates, and cardiac glycosides, and not anthraquinones (chuku et al., 2016) . crude methanol leaf extracts of e. camaldulensis from iran had saponins, tannins, volatile oils, and balsam (gum), while the components such as anthraquinones, hydrolysable tannin, flavonoid, alkaloid, and glycosides were not detected (jouki and khazaei, 2010) ; crude methanolic leaves extract of e. camaldulensis from india contained anthraquinones, flavonoids, saponins, and terpenoids, while alkaloids, cardiac glycosides, and tannins were not detected (singh and thakur, 2016) . phytochemical screening of the crude stem barks methanol extract of e. camaldulensis from bangladesh indicated presence of saponins, flavonoids, tannins, and also volatile oils, while anthraquinones, hydrolysable tannins, alkaloids, and glycosides were not present (islam et al., 2014) . the polyphenolic composition (flavonoids and phenolic acids and aldehydes) also was studied in the soluble fractions of the methanolic extracts of eucalyptus camaldulensis originating from two spain provinces, huelva and pontevedra: gallic, protocatechuic, vanillic and ellagic acids, and protocatechic aldehyde were identified, along with eriodictyol, quercetin, naringenin, vanillin, naringin, quercitrin, luteolin, and kaempferol (cadahia et al., 1997) . eucalyptus camaldulensis extracts are generally rich in tannins which vary qualitatively and quantitatively according to the origin of the samples, and consequently protoanthocyanidin levels were influenced by the geographical origin (cadahia et al., 1997) . antimicrobial activity of e. camaldulensis eo and extracts are well documented against many microorganisms listed in the table 4 . for easier comparison, all data commented here for eos were re-calculated from microliter per milliliter or microgram/milligram per milliliter to percentage (v/v or w/v), using the equitations presented in fig. 2 . we considered here only minimal inhibitory and minimal bactericidal concentrations, while results obtained using disc or agar diffusion methods were not discussed. however, mic/mbc results vary between several micrograms to several milligrams. such high variation does not seem as real, even taking into account variation in oil composition, and are rather a consequence of erroneous equalization of one microliter and one microgram, or typographical errors. for instance, there are some nonsense mics, such as 2000 μl/ml, that is practically impossible to obtain (salem et al., 2015) . in some manuscripts even a species was not precisely indicated (harkenthal et al., 1999; karpanen et al., 2008; warnke et al., 2009; tadtong et al., 2016) and these results were not considered in the present review. eucalyptus camaldulensis plant extracts and eos were tested against wide range of bacteria. the most frequently included gram positive bacterium in screening is s. aureus. minimal inhibitory concentrations in most studies were in range 0.07-0.5% indicating moderately high activity against this bacterium. beside s. aureus, antibacterial effect was confirmed against b. subtilis (0.17-0.34%), m. luteus (0.2-0.4%), and s. pyogenes (0.4-1.1%) akin et al., 2010; knezevic et al., 2016; khubeiz et al., 2016; reda et al., 2017; ostad asiaei et al., 2018) . activity of eos was examined aginst l. monocytogenes in only one study and mic was not obtained with the highest used concentration of 1.0%, and the same was reported for enterococcus durans (akin et al., 2010) . activity against gram negative bacteria has been documented in a greater extent and mics for the most frequently used model organism e. coli was in range 0.15-3.2%. sensitivity of other enterobacteria is similar, with mics in range from 0.05 to 0.32% for k. pneumoniae (khubeiz et al., 2016; ostad asiaei et al., 2018) , 0.16-0.32% for salmonella enterica subsp. enterica serovar typhimurium (khubeiz et al., 2016) ; 0.35-0.4% for serovars typhi, paratyphi, and 0.6% for s. enteritis (ostad asiaei et al., 2018). other enterobacteria are similarily sensitive: shigella soneii was inhibited with 0.3% of eo (ostad asiaei et al., 2018) , while proteus vilgaris was sensitive in a broad range from 0.25% (ostad asiaei et al., 2018) to more than 1.28% (khubeiz et al., 2016) . the published data for p. aeruginosa are in the same range as for p. vulgaris, which is not surprising, as both species are generally highly resistant to antimicrobial agents. on the contrary, a. baumannii which is also known to be multi-drug resistant, showed sensitivity to eo in a range 0.05-0.1% . the lowest mic among gram negative bacteria was recorded for a gastrointestinal pathogen v. parachaemoliticus (0.01%) (khubeiz et al., 2016) . although the gram positive bacteria are consider more sensitive to eos in comparison to gram negative, it cannot be applied for essential oils of e. camaldulensis, since the most sensitive bacteria are gram negative -a. baumannii and v. parahaemolyticus. the minimal bactericidal concentrations for most bacteria are equal to, or rarely up to 4 times greater than mics. this low range in mic/mbc < 4 indicates that e. camaldulensis eos act as bactericidal agents (pankey and sabath, 2004) . antibacterial effects of e. camaldulensis extracts have been examined in a wider extent than essential oils. inhibitory concentrations varied depending on extraction method, plant properties, and model organism, being in broad range from 0.08 μg/ml to 200 mg/ml. crude aqueous leaf extracts show lower activity against various bacteria (range 25-50 mg/ml) (abubakar, 2010) , while bark aqueous extracts were more effective, with mic from 0.1 mg/ml for propionobacterium acnes to 4.0 mg/ml for p. aeruginosa (mabona et al., 2013) . the antimicrobial activity of methanol, ethanol or petroleum leaf extracts of e. camaldulensis showed significant variation; for instance, mics against b. subtilis varied from 0.04 up to 200 mg/ml or against s. aureus 1.25-25 mg/ml (chuku et al., 2016; ayepola and adeniyi, 2008) . for most examined gram negative bacteria mics were in range 10-200 mg/ml, while p. aeruginosa was even more susceptible (mics 10-100 mg/ml). similar or better antibacterial effect showed acetone leaf extract, being active against examined bacteria in range 15-50 mg/ml. the highest activity was obtained with dichloromethen extracts, with mics for staphylococcus spp. in range 0.25-1.0 mg/ml, and even lower for b. subtilis, p. acnes and b. agri (mics 0.10-0.79 mg/ml). interestingly, generally highly resistant m. tuberculosis was sensitive to methanol, n-hexane or chloroform extract with mics in range 0.004-0.064 mg/ml, while m. bovis was slightly less sensitive with mics 0.01-0.05 mg/ml (lawal et al., 2012; gemechu et al., 2013) . the progresses made on the investigation of essential oils mode of action, especially against bacterial cell targets, gave new perspectives in this combat. the knowledge about the essential oils and their target(s) on bacterial cell is crucial to understand which parts of bacterial cell are affected. the essential oils antibacterial action is linked to oil hydrophobicity that increases cell permeability and consequent leakage of cell constituents (dorman and deans, 2000; lambert et al., 2001; helander et al., 1998; turgis et al., 2009; ultee et al., 2002; faleiro, 2011) . it is important to perceive that a disturbed cell structures may affect stability of other cellular structures in a cascade type of action (carson et al., 2002) . essential oils have several target sites on bacterial cells; however it seems that all are directly or indirectly connected to the primary effect of essential oils on the bacterial envelopes. first of all, eos may cause cell wall and membrane disturbance (lambert et al., 2001; oussalah et al., 2006) , which further can lead to the significant loss of intracellular atp (oussalah et al., 2006; turgis et al., 2009) , induction the synthesis of heat shock proteins (burt et al., 2007) , ph disturbance (turgis et al., 2009; oussalah et al., 2006) , and intracytoplasmic changes (e.g. coagulation, periplasmic space enlargement) (becerril et al., 2007) . although the number of studies dealing with the eo mechanisms of action is increasing, there are still many questions to be answered before the precise mechanism is revealed. this is at the same time one of the main limitations for eos and extracts wide usage as antimicrobials. thus, the so far knowledge must be further improved enabling the combat bacterial pathogens and its resistance. contemporary research of eos and extracts are also focused on mechanism that allows bacteria to regulate some physiological activities, such as virulence, competition amongst populations, motility, sporulation, conjugation, antibiotic production, and biofilm formation (rodriguez-garcia et al., 2014) . this system of intercellular communication, quorum sensing (qs), is based on production of the signal molecules, called autoinducers (abraham et al., 2011) . this communication system is relative to cell density and some compounds interfere with the qs communication system and attenuating the bacterial pathogenicity, in the phenomenon known as anti-qs compounds (abraham et al., 2011) . there are reports of anti-qs activity of various plants species eos from genus eucalyptus, such as eucalyptus globulus l. (luís et al., 2016; cervantes-ceballos et al., 2015) , eucalyptus radiata d. (luís et al., 2016) , eucalyptus citriodora hook., eucalyptus smithii r. t. baker and eucalyptus staigeriana f. muell. ex bailey (luís et al., 2016) . unfortunately, there is still no data regarding e. camaldulensis anti-qs activity. in one study, antibacterial and in vivo biofilm preventive efficacies of e. camaldulensis oil were significantly higher than that of m. spicata oil and chlorhexidine, suggesting that e. camaldulensis eo is capable of fig. 2 . schematic diagram for re-calculation from microliter or milligram per milliliter to percentage (v/v or w/v). affecting biofilm formation . considering the anti-qs activity of above mentioned eucalyptus species and also detected antimicrobial and anti-biofilm effect of e. camaldulensis it can be assumed that it possess similar or even higher anti-qs activity. however, future detailed studies of anti-qs and anti-biofilm e. camaldulensis activity are needed in order to confirm this assumption. the e. camaldulensis leaves extracts and eos have a potential as antifungal agents. they are able to act as a moderate antifungal agent against household molds, wood rot fungi (siramon et al., 2013) , and phytopathogenic fungi (gakuubi et al., 2017; mehani et al., 2014) . eucalyptus camaldulensis eo has been studied for antifungal activity and was active in concentration 0.125-1.0% against most model organisms. the most sensitive seems to be f. sporotrichioides with mic 0.125% (mehani et al., 2014) , while r. oryzae is the most resistant, as 1% of eo was ineffective against this fungus (siramon et al., 2013) . the best known human and animal pathogenic yeast candida sp. showed considerable sensitivity to e. camaldulensis eo, with mic approx. 0.5% (siramon et al., 2013; nasir et al., 2015) . most eos from sardinia inhibited growth of a. niger and b. cinerea in concentration of 20 μl/plate, while lower concentrations of the oils, such as 5 μl/plate were ineffective (barra et al., 2010) . it is interesting to notice that liposomes containing e. camaldulensis eo were prepared (moghimipour et al., 2012) for antifungal oil activity. the particle size varied from 40.5 to 298 nm for the different formulations, with approx. 95% of the essential oil entrapped. inhibition of microsporum canis, m. gypseum, trichophyton rubrum, and t. verrucosum was achieved with 125 μl, and the liposomal gel formulation of the eo was proposed to improve antifungal activity. aqueous and organic extracts of e. camaldulensis have been reported to have antifungal activity (table 4 ). methanol leaves extracts showed inconsistent activity against c. albicans: in one study it was in range 50-200 mg/ml (chuku et al., 2016) , while in another it was 0.2 mg/ml (babayi et al., 2004) , indicating difference in active concentration of one thousand times. the bark methanole extract was active in concentration 0.5 mg/ml. methanol leaf and bark extracts showed considerable activity against dermatophytes: 0.8-1.6 mg/ml against microsporum spp, 0.125-1.6 mg/ml against trichophyton spp., and 0.2 mg/ml against epidemophyton flocossum (takahashi et al., 2004; falahati et al., 2005; mabona et al., 2013) . beside the antifungal activity of eos and extracts of e. camaldulensis, it is worth noticing that this species, along with e. blakelyi m., e. gomphocephala a. dc, e. rudis endl., and e. tereticornis sm., is a reservoir of an emerging pathogenic fungus -cryptococcus gattii. this fungus is usually related to tropic and subtropic regions, affecting the respiratory and nervous systems of the immunocompetent humans and domestic animals (sorrell et al., 1996; chakrabarti et al., 1997; bielska and may, 2016; roe et al., 2018) . similarily, c. neoformans var. grubii can be isolated from flowers and bark of e. camaldulensis (gugnani et al., 2005) . according to the literature, e. camaldulensis is natural reservoir of cryptococcus and is considered responsible for occurring cryptococcosis worldwide. in this context, it is interesting to observe that c. neoformans is moderately sensitive to e. citriodora hook eos, with mic90 0.5% (wt/v) (pattnaik et al., 1996; luqman et al., 2008) or e. globulus labill. with mic 0.13% (wt/v) (suliman et al., 2010) . unfortunately, data on cryptococcus sp. sensitivity to eos and plant extracts of reservoir species of eucalyptus, including e. camaldulensis, remains unknown. although there are no reports regarding e. camaldulensis mode of antifungal action, according to previous studies with other essential oils and fungi, the plasma membrane and the mitochondria are the probable antifungal targets of eos. according to recent studies, the antifungal activity of eos results from its ability to disrupt the permeability barrier of the plasma membrane and from the mitochondrial dysfunction-induced ros accumulation in a. flavus and c. albicans (tian et al., 2012; chen et al., 2013) . the exact mechanism of e. camaldulensis antifungal activity is unknown and should be elucidated in the future. infections caused by viruses are very common and sometimes life threatening, especially in immunocompromised patients and neonates (snoeck, 2000; khan et al., 2005) . despite the recent significant progress in antiviral drug development, viral infections are considered as one of the major causes of death worldwide (müller et al., 2007; meyers et al., 1982) . thus, novel natural antiviral agents need to be found urgently. many natural products possess antiviral activity and some of them are already in use for treatment of human viral infections with both rna and dna viruses (e.g. myricetin against coronavirus, linalool, urosolic acid, and apigenin against coxsackievirus, quercetin and narasin against denge virus, curcumin against hepatitis b and c virus) (lin et al., 2014; kitazato et al., 2007) . numerous secondary plant metabolites such as essential oils, flavonoids, saponins, tannins, alkaloids, lignans, terpenes, and phenolic acids express significant antiviral activity against different viruses (jassim and naji, 2003; chiang et al., 2003; sanchez palomino et al., 2002) . recently few studies confirmed the e. camaldulensis eos and plant extracts antiviral activity (table 4) . eucalyptus camaldulensis eos reduce coxackie b4 and rotavirus wa multiplication for 50%, herpes simplex virus 1 for 90%, but have no effect on adenovirus 7 multiplication (el-baz et al., 2015) . similarly, methanolic extracts showed 50% inhibition of hsv 1 and 2 in concentration 0.1-0.3 μg/ml, and against varicella zoster virus at concentration 1.0 μl/ml (abu-jafar and huleihel, 2017). dimethyl sulfoxide (dmso) extracts inhbit multiplication of animal new castle virus in concentration range 50-500 μg/ml (al-hadid, 2016) . antiviral activity has been observed for e. camaldulensis methanolic extracts against polio virus, coxsackie b, and echovirus 6 (adeniyi et al., 2015) . the data on antiviral activity of e. camaldulensis eo and extracts, although scarce, indicate their great potential, and necessity for further studies in this context. despite the fact that many plant extracts and essential oils were previously reported for their antiviral activities, the mechanism of action still remains poorly understood. there are many factors that influencing the eos mode of action, which should be taken in consideration when antiviral activity of plant antimicrobials is examined. one of such factors is the difference between enveloped and non-enveloped viruses, because the observed antiviral effect has usually been greater for enveloped viruses (yamada et al., 2009; siddiqui et al., 1996) . in majority of the studies dealing with antiviral mode of action, the focus has been on either the inhibition of viral adsorption to host cells or examination of the plant antimicrobials effectiveness against intracellular virus multiplication (gilling et al., 2014) . so, most commonly described modes of antiviral actions are virus inactivation and the impaired virus adsorption to host cells, which is often difficult to distinguish. like in other antimicrobial modes of action, antiviral mechanism is also dependent on eos or extracts compounds activity. this is one more factor that should be considered, because it affects the final antiviral mechanism of action. for some compounds the potential mechanism is reported, i.e. carvacrol acts directly upon the virus capsid and subsequently the nucleic acid (gilling et al., 2014) . when eos antiviral mechanism of action is considered, eos may cause the loss of the viral capsid integrity, ultimately leading to exposure of the viral genome. in addition, some eos subsequently act directly upon the viral nucleic acid (dna or rna). according to one study, e. camaldulensis eos may be promising antiviral agent against rna viruses with no effect against dna virus (el-baz et al., 2015) . also, with shorter periods of exposure to the antimicrobial, the virus is able to adsorb specifically to host cells; however, it may or may not be able to cause successful infection depending upon the integrity of the viral genome. on the other hand, after exposure to some eos virus capsid and genome remains intact. these antimicrobials appear to exert their antiviral effect by coating the capsid and thereby preventing specific adsorption of the virus to host cells (gilling et al., 2014) . although, there are still no reports regarding e. camaldulensis eos antiviral mode of action, there are some promising results about its antiviral effect (table 4) . these promising results represent foundation for further research and potential application of e. camalulensis eos as potent antiviral agent. among all deverse benefitial activities, e. camaldulensis expresess also an antiprotozoal effect as well. the reports regarding this effect are listed in table 4 . eucalyptus camaldulensis methanolic and aqueous extracts were active against leishmania major with ic50 values (50% inhibitory concentration) 586.2 ± 47.6 and 1108.6 ± 51.9 μg/ml, respectively (nosratabadi et al., 2015) . this was characterized as moderate leishmanicidal activity, but considering fact that present therapy consist antimony compounds which are expensive, toxic, and drug resistance is prevalent, e. camaldulensis plant extract derivatives represent safe, inexpensive, and promising alterantive solution. there are also several reports regarding antiprotozoal activity against trichomonas vaginalis, a causative agent of trichomoniasis which is the most prevalent nonviral sexual infection. the first report on e. camaldulensis aqueous extract anti-trichomonas activity showed that extract was active at concentration 500 mg/ml after 24 h (mahdi et al., 2006) . however, recent studies reported better effect of the e. camaladulensis extracts (hassani et al., 2013; youse et al., 2012) . five different e. camaldulensis leaves extracts including total extract, diethyl ether, chloroform, ethyl acetate, and water fractions were active in concentration range 12.5-50 mg/ml, with growth inhibiton achived after 24-72 h (hassani et al., 2013) . ethyl acetate fraction showed the highest percentage of growth inhibition with the lowest concentration (12.5 mg/ml) after 24 and 48 h (hassani et al., 2013) . even better antitrichomonas activity was detedted for wather and ethanolic extracts, where concentration 60-90 μg/ml killed trichomonas vaginalis for 72 h (youse et al., 2012) . the mainstay medication for trichomoniasis is metronidazole; however some resistant strains to this treatment have been detected making these results of e. camaldulensis anti-trichomonas activity very promising as antiprotozoal agent. except extracts, significant antiprotozoal activity was reported for e. camaldulensis eos. the essential oils were found to possess antitrypanosomal activity in vitro in a dose-dependent manner in a short time. the decrease of trypanosoma evansi number over time was achieved in doses of 400 mg/ml for 3 min, 200 mg/ml for 4 min, and 100 mg/ml for 15 min. against trypanosoma brucei brucei eos was more potent in the concentration of 400 mg/ml, decreasing the number of parasite for 3 min, 200 mg/ml for 4 min, and 100 mg/ml for 11 min (habila et al., 2010) . such prompt decrease in parasite number in the in vitro tests for both trypanosoma brucei brucei and t. evansisuggests that the eos kill the parasites efficiently, but by an unknown mechanism. there are suggestions of some potential mechanisms of antiprotozoal eos action. the activity of eos could be due to the hydrophobic nature of the cyclic hydrocarbons, which allow eos to interact with the protozoans causing conformational changes in the parasite membrane structure, resulting in the loss of membrane stability (calsamiglia et al., 2007) . the essential oils also can act by inhibiting some key enzymes in the parasite glycolytic pathway (smith-palmer et al., 2004) . furthermore, some eos components inhibit acetylcholinesterase activity and act on other vulnerable sites, such as cytochrome p450 (maciel et al., 2010) . this multicomponent nature of plant eos is an advantage for several target sites on protozoans, which is of great importance. it was shown that eos of e. camaldulensis are more potent against b. subtilis, s. aureus, e. coli, p. aeruginosa, s. lutea, and p. carotovorum in comparison to eos from e. gomphocephala dc., but not against a. tumefaciens. furthermore, the e. camaldulensis var. obtuse showed even better effect than e. camaldulensis (salem et al., 2015) . among seven examine essential oils of various eucalyptus species, eo of e. camaldulensis was among the best against b. subtilis, a. niger, and r. solani, but not against e. coli and s. aureus (ghaffar et al., 2015) . similar activity of e. camaldulensis and e. torelliana f. muell. was recorded for extracts against six strains of h. pylori (adeniyi et al., 2009) . it is worth to notice that among 132 extracts from 42 plants growing in southern africa, e. camaldulensis bark extract showed considerable activity against bacteria and fungi, with an exception against p. aeruginosa and m. canis (mabona et al., 2013) . finaly, in many studies regarding antimicrobial activity of various eucalyptus species, e. camaldulensis was not always included (ashour, 2008; safaei-ghomi and ahd, 2010; mulyaningsih et al., 2010; elaissi et al., 2012; sebei et al., 2015) . due to rapid emerging of microbial resistance to conventional drugs, the necessity for efficient solution(s) is rising. the main strategy represents finding new antimicrobial agents; however another strategy goes in the direction of reducing degree of bacterial resistance and/or bacterial re-sensitization to conventional antibiotics. this can be achieved using combined therapies. the most of the tested combinations are dual combinations, but the combinations of three, four or more agents also can be efficient (lesjak et al., 2016) . this is in line with antimicrobial efficiency and potential of eos and plant extracts which are complex mixtures of numerous compounds. combination strategy could be very promising regarding the diversity of agents that could be tested: (1) conventional non-antimicrobial agent (e.g. anti-inflammatory or anti-psychotic drug) + conventional antimicrobial agent (antibiotic); (2) conventional antimicrobial agent (antibiotic) + natural antimicrobial agent (essential oil, plant extract, bacteriophage, antimicrobial peptide ect.); (3) conventional antimicrobial agent (antibiotic) + single compound isolated from natural antimicrobial agent (with previously confirmed antimicrobial activity); (4) combination of two or more single compounds isolated from natural antimicrobial agents (with previously confirmed antimicrobial activity). being a plant with already detected and evaluated antimicrobial activity, it can be assumed that e. camaldulensis also have a potential in combined therapy. this assumption is confirmed in some studies in vitro and in vivo (table 5) . eucalyptus camaldulensis eos and extracts in vitro reduced resistance of mdr a. baumannii in combination with conventional antibiotics: β-lactams, ciprofloxacin, gentamicin, polymyxin b . similarily, the increase of β-lactamase produing mrsa and e. coli sensitivity to cephalexin, cefuroxime, amoxicillin, and ampicillin has been obtained through combination with e. camaldulensis eos (chaves et al., 2018) . synergistic activity has been recorded between e. camaldulensis plant extracts and gentamicin or ceftriaxone against mdr s. aureus and p. aeruginosa (reda et al., 2017; ibrahim et al., 2014) , as well as in combination with ampicillin against s. aureus (ibrahim et al., 2014) . furthermore, the combination of e. camaldulensis extract with another plant extract psidium guajava l. was also efficient against mdr bacteria (bala et al., 2014) . except antibacterial activity, other activities of e. camaldulensis extracts in combination were detected and characterized as efficient. antiviral activity was confirmed for the combination of e. camaldulensis 80% methanol leaves extract and acyclovir against herpes simplex virus -1 and -2 and varicella-zoster virus (abu-jafar and huleihel, 2017). similaily, the combination of annona senegalensis l. leaf methanol extract and e. camaldulensis extract efficiently cured in vivo albino mice infection with parasite trypanosoma brucei brucei (lafia strain) (kabiru et al., 2012) . all these data are very promising, but the methods used in different studies and results interpretation vary (table 5) . as a consequence, the data should be taken with precautions, as can not be compared and properly discussed. to avoid this problem, the testing combinations of different agents should be conducted using standardized methods, such as time-kill method (clsi, 1999; verma, 2007) , checkerboard method (verma, 2007; eucast, 2000) , chou-talalay method (chou, 2010) or boik method (boik, 2010) . all these methods possess some shortfalls, such as timeconsuming, labor-intensive, limitations regarding the number of the agents in combination, etc. unfortunately, there is no one gold standard for synergy testing and prior the further application of different phytochemicals, this issue should be overcome. summarizing the available data on antimicrobial properties of eucalyptus camaldulensis essential oil and extracts, it is obvious that this plant is a valuable source of phytotherapeutics. the essential oil, as well as leaf and bark extracts are particularly valuable as antibacterial, antiviral, and antifungal agents, and their antiprotozoal activity should not be neglected taking into account current therapy cost, toxicity, and protozoal growing resistance. some e. camaldulensis plant characteristics such as easy cultivation, wide distribution by plantation, and rapid growth additionally support further examination of antimicrobial activity, in order to enhance the commercial production of e. camaldulensis based pharmaceuticals. the future studies should be focused on determination of the mechanisms of antimicrobial activity, paticularly potential anti-biofilm and anti-qs effects, as well as the activity enhancement in combination with other available agents. effects of eucalyptus camaldulensis and other antimicrobial agents in combination. two-dimensional checkerboard method (verma, 2007) synergism (fici ≤ 0.5) knezevic et al. (2016) leaf essential oil from brazil the mic of the antibiotics were determined in the presence and absence of sub-inhibitory concentrations (125 μg ml −1 ) of the essential oil (coutinho et al., 2010) combining the essential oil with β-lactams reduced the resistance of tested strains agar disc diffusion method was employed as described by kirby and bauer (1966) , adopted by yushau et al. (2009) and bashir et al. (2011) synergism bala et al. 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astragalosides in radix astragali optimization of furfural and 5-hydroxymethylfurfural production from wheat straw by a microwave-assisted process effect of echinophora platyloba, stachys lavandulifolia, and eucalyptus camaldulensis plants on trichomonas vaginalis growth in vitro in-vitro sensitivity pattern of some urinary tract isolates to carica papaya extracts the essential oil of the leaves and the fruits of e. camaldulensis essential oils of twentyseven eucalyptus species grown in morocco key: cord-336165-if8uxqha authors: remoaldo, paula; serra, jaime; marujo, noémi; alves, juliana; gonçalves, alexandra; cabeça, sónia; duxbury, nancy title: profiling the participants in creative tourism activities: case studies from small and medium sized cities and rural areas from continental portugal date: 2020-09-12 journal: tour manag perspect doi: 10.1016/j.tmp.2020.100746 sha: doc_id: 336165 cord_uid: if8uxqha although cultural tourists increasingly seek to experience cultural events actively and to directly engage in creative activities, empirical knowledge about the creative tourist remains limited. this study aims to characterize the motivations and profile of creative tourists. the data was collected through a survey of participants in creative tourism activities in portugal developed by 40 pilot institutions of the creatour project during 2017 and 2018, with 814 usable questionnaires collected and validated. the questionnaire had 30 questions and marked the first time this kind of research was conducted in portugal. the questionnaire included questions on: the composition of their travel companions, their previous participation in a creative tourism experience, reasons for visiting the destination, their characterization of the creative tourism experience, an evaluation of their creative tourism experience, and their socio-demographic profile. using a cluster analysis to analyse the data, three clusters were found: novelty-seekers, knowledge and skills learners, and leisure creative-seekers. in the 1980s, alvin toffler (1980) pioneered the concept of "prosumer" to refer to a type of consumer involved in product design and in production itself. with the diffusion of the concept of prosumer -a fusion of the words "producer" and "consumer" -since that time, the consumer has become the producer of many of the products and experiences he consumes. the diffusion of this concept coincides with the emergence of a new generation of tourists, also called "qualified consumers" or "creative consumers" (carvalho, ferreira, & figueira, 2016; mihajlović & koncul, 2016; pappalepore, maitland, & smith, 2014; richards, 2010a; richards & wilson, 2006; zhang & yu, 2018) , postmodern travellers (carvalho et al., 2016; jelinčić & žuvela, 2012; o'dell, 2007; pappalepore et al., 2014; tan, luh, & kung, 2014) or "creative tourists" (raymond, 2003; smith, 2016; tan et al., 2014; zhang & yu, 2018) . regardless of the term applied, they all refer to tourists who actively create their experience in the destinations they choose. this new consumer of experiences has played an increasingly active role in the economy, leaving aside the passivity characteristic of the 1980s, to play an essential role in market communication (egger, gula, & walcher, 2016; kotler, kartajaya, setiawan, & vandercammen, 2012; tan et al., 2014; zhang & yu, 2018) . for alvin toffler (1980) , the concept of prosumer defines a type of consumer of the future, involved in the design and production of products to make them more personalized and individualized. in addition, prosumers are more informed, more educated and with an aboveaverage level of demand. in this sense, the creative tourist can be seen as a prototype of the prosumer (fundação de serralves, 2008; tan et al., 2014; egger et al., 2016; zhang & yu, 2018) . there is a great diversity of definitions of creative tourists, ranging from those that refer to participants in dance art experiences or handicraft workshops, to those that include people temporarily residing in artistic residences in search of creativity. according to richards (2011) , creativity can be used to implement creative tourism as a tourist activity, which involves the active involvement of tourists in the creative activities of the places they visit, or as a backdrop for tourism, in which tourists place themselves in a chosen creative environment. nevertheless, despite these efforts, defining the concept of creative tourism and describing the motivations and profiles of those who https://doi.org/10.1016/j.tmp.2020.100746 received 4 may 2020; received in revised form 1 september 2020; accepted 2 september 2020 engage in creative activities during their holidays are not easy tasks. the term "creative tourism" is relatively young and began to draw attention in the scientific milieu in the 1990s. pearce and butler (1993) were the first to mention creative tourism as a potential form of tourism. the definition most used by the experts in this area is the one elaborated by richards and raymond (2000) , who define creative tourism as offering tourists the opportunity to develop their creative potential through active participation in courses and learning experiences that are the characteristics of the destination in which they are carried out. over the last two decades, tourist demand has become increasingly exacting, segmented and constantly changing (fundação de serralves, 2008; tan et al., 2014; carvalho et al., 2016; smith, 2016; zhang & yu, 2018) . this process points to the emergence of a new tourist profile and, consequently, a new pattern of consumption that is directed toward the use of creativity as an alternative to mass cultural tourism. creative tourists are not satisfied to only observe cultural events and passively visit cultural spaces, but seek to experience them actively. they seek memorable events (pine & gilmore, 1999) and usefulness rather than novelty (tan, kun, & luh, 2013) . there are mindful visitors (moscardo, 1996) who want to become a part of the destination's everyday dynamics (ilincic, 2014) and ask for active participation and greater involvement with the local community (carvalho et al., 2016; mihajlović & koncul, 2016; ohridska-olson & ivanov, 2010; richards, 2003; richards & raymond, 2000; richards & wilson, 2007; smith, 2016; zhang & yu, 2018) . generally, creativity is associated with urban areas, especially large cities. this relationship between creativity and the city derives from the fact that creative industries have been greatly responsible for dynamizing the attractiveness of the cities, making them more attractive for companies, for new inhabitants and, consequently, for tourists (argent, tonts, jones, & holmes, 2013; boes, buhalis, & inversini, 2015; dekker & tabbers, 2012; richards, 2011; richards, 2014a) . this new type of tourist results from the depleted model of massified cultural tourism which does not gives him/her opportunities to have an active role. this depleted model can be clearly observed in southern europe countries that have been suffering from a high pressure of visitors in recent decades. in portugal (the territory analysed in the present paper) massified cultural tourism began to occur in recent years, especially in large cities like lisbon and porto. creative tourism appears as an opportunity to reinvent the current tourism model and offer a form of tourism that is more sustainable and close to the local community. the profile of cultural tourism is well defined and supported by a long spectrum of scientific research, but little is known about the creative tourist. the few international studies dedicated to the profile of the creative tourist continue to highlight the complexity of this segment, which involves tourists from multiple generations (children, adults and the elderly) looking for authenticity, exclusivity, improving skills and desiring contact with the local community. noting that these insights are derived from a generalized international level, the profile of the creative tourist has not been clearly characterized in portugal, especially the one that visits small and medium-sized cities and rural areas. in the research presented in this article, we specifically analyse the profile of this kind of visitor. we studied the tourists who participated in creative tourism experiences carried out by 40 institutions involved in the creatour project, located in the four nuts ii regions of continental portugal (norte, centro, alentejo and algarve). the creatour project "creative tourism destination development in small cities and rural areas" (https://creatour.pt/en/) was in process from november 2016 to june 2020. as a research-andapplication project, creatour developed an integrated approach to creative tourism development in small cities and rural areas across portugal. on the research side, the project aimed to examine and reflect on the creative tourism activities, including development dynamics and patterns, reception experiences, and community impacts, using methodologies and theoretical perspectives from the fields of tourism, cultural development, and local/regional development. on the practice side, it aimed to catalyse creative tourism offers in small cities and rural areas in portugal, inform and learn from their development, and link them with each other through the development of a national network (duxbury, 2020) . the project was funded by feder through the joint activities programme of compete 2020 and the regional operational programmes of lisbon and algarve and co-funded by the portuguese foundation for science and technology (fct/mec). taking a cultural development approach, creatour fostered a diversity of "bottom-up" ideas and experimentation in which 40 pilot projects were independently designed, implemented, and managed, but coupled with knowledge-sharing and capacity-building through networking. the creative tourism activities developed ranged widely, including: craft workshops involving textile, pottery, ceramics, leather, metal, and wood; fine arts workshops such as painting, sculpture, drawing, and illustration; photography, video, and digital arts workshops; performing arts workshops and community-engaged, participatory artistic residencies; storytelling sessions and workshops; gastronomy-focused workshops in which visitors learn food-related cultures of a place as well as culinary techniques to take home; imaginative "walks & visits" involving creation activities; ancestral traditions workshops and active participation activities; and activities related to raw materials production and work cycles for making, for example, salt, linen, wool, clay, marble, wicker, and so forth. this paper aims to characterize the profile of the tourists who participated in these activities and their motivations, attending to the following three questions: who are the participants in creative tourism activities? what are the main motivations to attend a creative tourism activity? can motivation be used to segment creative tourism participants (i.e., are creative tourists motivation-driven)? for the analysis of the data, descriptive and multivariate statistics have been developed through the program statistical package for the social sciences (s.p.s.s. version 22.0). this paper is organized as follows. after the introduction, section 2 presents a literature review of creative tourism and the creative tourist. the research methods are presented in section 3. the results and discussion are presented in section 4. finally, in section 5 the conclusions and some policy and managerial implications are presented. the development of creative tourism phenomena is linked to recent developments in cultural tourism. cultural tourism corresponds to the tourism in which cultural attractions are the main reason to visit or stay in a certain destination (csapó, 2012; mousavi, doratli, mousavi, & moradiahari, 2016; richards & wilson, 2006; williams, 2010) and that offers the visitor an opportunity to understand and appreciate the culture and essence of a place (kajzar, 2013 (kajzar, , 2014 richards, 2014b) . creative tourism emerged in response to a market that has specific needs. although it is the central theme of a growing number of investigations, the concept of creative tourism still remains quite vague in the scientific environment (richards, 2011 (richards, , 2014b tan et al., 2013; hung, lee, & huang, 2016; smith, 2016; creative tourism network, 2018; remoaldo et al., 2019; remoaldo, matos, gôja, alves, & duxbury, 2020; duxbury & richards, 2019a) . many definitions of creative tourism are linked to cultural tourism, and is generally understood as a form of cultural tourism that allows for a more authentic approach between the tourist and residents (briggs, 2005; gordin & matetskaya, 2012; jelinčić & žuvela, 2012; king, 2009; ohridska-olson & ivanov, 2010; richards, 2010b; richards, 2014a; richards & raymond, 2000; virginija, 2016) . creative tourism is oriented to immaterial resources such as learning, developing experiences and traditions (ribeiro et al., p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 2020). this tourist is someone who wants to not only see the region but to experience it (virginija, 2016) . in this sense, creative tourism is a participatory form of cultural tourism more appropriate to contemporary social and economic structures. this type of tourism makes use of the intangible resources of the destination (e.g., lifestyles, narratives, creativity, media) and enables the tourist to participate actively in leisure, cultural and artistic activities that reflect the characteristics of the destination visited. it is a special form of tourism that creates the necessary conditions for travellers to exercise their and participate in creative workshops and activities (e.g., arts and heritage -brouder, 2012; rudan, 2012; hung et al., 2016) , which allows for a truer and more authentic experience in the destination. this new demand for deep immersion in the experiences consumed reveals a new profile of tourist. although there are attempts to characterize this new tourist (carvalho, ferreira, & figueira, 2011; florida, 2002; mota, remoaldo, & ribeiro, 2012; remoaldo, vareiro, & ribeiro, 2017; richards, 2010a; richards & wilson, 2007; silberberg, 1995; tan et al., 2014) , no consensus has yet been found. this new tourist wants a more authentic experience, immersed in the local cultural capital and close to the community (guerreiro & marques, 2017; remoaldo et al., 2020) . this trend is a response to the saturation of mass cultural tourism (richards, 2010a) . in this sense, creative tourism develops the social and cultural capital of tourists, as they become co-authors of their tourism experience, contributing to authentic, immersive and exclusive experiences (pine & gilmore, 1999; richards, 2014b; virginija, 2016) . the characteristics of the cultural tourist are very close to the ones of the traveller seeking creative experiences. cultural tourists, for the most part, exhibit different expectations and motivations from those of the "modern" tourists (smith, 2003) . one of the characteristics that distinguishes cultural tourists from the people who engage in creative activities comes from the intensity of the motivations (which may be, to a greater or lesser extent) to live new experiences, as well as the degree of involvement and interaction that the tourist establishes with the local community (smith, 2016) . creative tourists seek to enjoy participatory and authentic experiences and, mainly, generate their own experiences (prahalad & ramaswamy, 2004) , exercising co-creation (binkhorst, 2007; puczkó, 2013) . throughout the twentieth century, the attitude of tourists has undergone several changes and, on the whole, tourists have become more demanding. they have begun to look for experiences during their holidays as a way to develop their skills and take an active part in the culture of a place (richards, 2010b) . this search for learning is not an absolutely new and intrinsic feature of the creative tourist. completely to the contrary, this characteristic has been gaining expressiveness over the last two decades and is a central element of the experiences in creative tourism (anderson, 2009; peters, frehse, & buhalis, 2009; raymond, 2007; tan et al., 2013) . these tourists wish to contact and learn more about specific aspects of the culture of a particular community through active participation with the local community and the development of their creative skills in workshops and other activities (cortada, 2006; raymond, 2003; richards, 2003; richards & raymond, 2000; richards & wilson, 2007) . this kind of tourist assumes the role of co-creator, co-producer and consumer of the experiences and skills of the promoters of experiences (e.g., trainers, local community), that is, the tourist is involved in the local culture through making artefacts or products in the destination (e.g., handicrafts, gastronomy, art) (anderson, 2009; binkhorst, 2007; maisel, 2009; peters et al., 2009; prentice & andersen, 2007; ray & anderson, 2000; raymond, 2007; richards & wilson, 2006; tan et al., 2013) . in addition, the participant in creative tourism activities wants higher levels of social, emotional and educational interaction with the community and to feel like part of the destination (binkhorst & den dekker, 2009; richards, 2014b; smith, 2016; stolarick, denstedt, donald, & spencer, 2010) . investigations previously carried out on the profile of the creative tourist reveal that the existing segments are different and show that the creative tourist covers a wide range of travellers. what we do know is that the creative tourist tends to appreciate authenticity and cultivates the desire to get to know the local culture in a more "alternative" way that is closer to the local community. despite these attempts, the definition of the creative tourist is still very generalist and imprecise, many studies that claim to be about the creative tourist do not actually correspond to that segment of tourism, and further research about the creative tourist is still needed (duxbury & richards, 2019b) . in the next section, some international case studies are reviewed that present more detailed information on the profile of the creative tourist. creative tourism seekers tend to belong to the creative class (florida, 2002) , that is, a cosmopolitan class from the middle and upper layers of society which shares higher levels of education. internationally, a few research surveys present the characteristics and behaviour of these contemporary tourists (see table 1 ), but the body of research is still very limited and needs further theoretical development. source: authors' elaboration. p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 in the early 2000s, raymond (2003) , based on a case study in new zealand (table 1) , presented a proposal to segment and profile creative tourism seekers based on general demographic profiles, proposing three groups: baby-boomers and retired, tourists under 30 (e.g., students and backpackers) and new zealanders who are interested in learning more about different aspects of the culture of their country. in 2009, a survey of participants from two creative tourism pilot events in the uk concluded that the participants were predominantly female, aged 45 or more years of age. the other large group was made up of younger women aged between 22 and 30 with busy full-time jobs and no children (campbell, 2010) . in 2014, tan et al. identified five distinct groups of creative tourists in taiwan -novelty-seekers, knowledge and skills learners, those who are aware of their travel partners' growth, those who are aware of green issues, and the relax and leisure type -by analysing 46 q-statements about creativity and creative experiences. in 2015 in bali, indonesia, another attempt to establish the profile of the creative tourist in creative tourism experiences of rural communities was presented by blapp (2015) . in total, 15 tourists' groups were interviewed based on an opportunistic sampling strategy. the interviews were limited to western tourists given the scope of the research to focus on creative tourism geared toward the western market (blapp, 2015) . in 2016, ali et al. examined the effect of creative tourists' experiences on their memories, satisfaction and behavioural intentions. a total of 296 surveys were conducted with guests at six selected resort hotels in malaysian states of terengganu and kedah who participated in creative activities, cooking classes, handicraft classes, storytelling sessions of local tales and 'batik painting'. the largest number of tourists was aged between 31 and 40 years (60%). females were predominant (54%), with three-quarters of them being malaysian (72%) and around one-quarter being foreigners (28%). in 2019, huang et al. conducted an empirical study in three popular creative tourism attractions in taiwan: meinong, singang and yingge. the following creative activities were developed: pottery, handicrafts and arts making. the majority of the 395 tourists surveyed was aged between 31 and 40 years and females were also predominant (59.2%). in portugal, a study on the influence of the creative industries on tourism in the city of porto (city break predominant tourism segment) presented the tourist profile in this city. in the sample collected of 385 tourists, males were predominant and their motivations were broader than participating only in creative activities. the tourists were from spain, aged between 19 and 25 years, single, with a high academic degree (bachelors or masters) and with high annual income (€15,000-€22,499) (barbosa, 2014) . concerning their motivations, for 65% of the respondents the main reason for their trip to porto was a vacation, 18% visited the city to visit friends or relatives and 5% visited to attend cultural events or attractions. regarding attending cultural or creative activities, 47% of respondents in this research responded positively (e.g., participating in serralves em festa, nos primavera sound, são joão, queima das fitas, axa street art, verão na casa da música) while 53% did not attend any cultural or creative activity (barbosa, 2014) . another study developed by melo, correia, cardoso, and marques (2019) analysed the perspectives of visitors and suppliers concerning the experiences of creative tourism in guimarães, portugal (a unesco world heritage destination) and identified that the majority of the respondents had not heard about creative tourism before (82% in total; n = 115). the authors reported that 50.7% were male and between 38 and 49 years old, and highlighted that 80% of the tourists come from the following countries: 35.7% from brazil, 18.8% from spain and 12.5% from france. most respondents had higher education degrees and an income higher than 501 euros/month. although these portuguese studies are not precisely about the profile of the creative tourist, they are important contributions to the study of the profile and motivations of visitors and help us to understand the visitors' profile for portuguese destinations. as we have previously noted, unravelling the profile and motivations of the creative tourist is not an easy task. the case studies reviewed showed that research on the traits of those engaged in creative tourism profile is still a little explored path. one of the possible explanations for this omission is the complexity of creative tourism as a wide variety of activities can be consumed within the creative tourism label. one can ask the following questions: do the characteristics of this profile depend on the type of activity consumed? for example, does the tourist who participates in the estival festival (held in the centro region of continental portugal) have the same characteristics (or similar characteristics) and motivations of a tourist who participates in a pottery workshop (held in the alentejo region of continental portugal)? our research was carried out in 2017 and 2018 with the participation of four research groups located in four regions of continental portugal: norte, centro, alentejo, and algarve. overall, 814 questionnaires were completed by participants in the creative tourism activities implemented by the 40 pilot institutions that were selected to join the creatour project ( fig. 1) . a wide array of organizations located in small and medium-sized cities and rural territories had submitted project proposals to develop creative tourism offers, and the 40 organizations selected to be co-researchers in creatour were monitored within the project until the end of 2019. the research presented here segmented the tourists based on their motivation to participate in creative tourism activities and analysed the resulting profiles. the questionnaire was designed based on a literature review of creative tourism, tourist motivations and cultural tourist profiles. a total of 10 motivation items were considered in this study ( table 2 ). the questionnaire consisted of 31 closed questions oriented to the participant's profile, motivations, perceptions and evaluation of activities, as well as the impacts on the local economy (e.g., accommodation, meals and local commerce). in order to analyse this data, multivariate statistics was used to simplify the data, describing the information through a small number of dimensions of analysis (reis, 2001) . hair, anderson, and tatham (1998) state that there are traditionally three types of segmentation techniques, being mostly of an exploratory nature. some of these techniques are in a general area of multivariate data analysis traditionally known as data reduction or reduction of dimensionality. using spss statistics 22.0, the first procedure (the exploratory factor analysis) started with motivation variables (table 2) . after this procedure, a hierarchical cluster analysis, based on the tourists' motivation using ward's method and the squared euclidean distance, was carried out to identify homogenous groups of respondents. a three-cluster solution was identified based on the dendogram and the agglomeration schedule. from the analysis of the output, chi-square tests (for qualitative variables) and t-test (quantitative variables) were carried out to characterize the clusters and to identify statistically significant differences concerning the following topics: reasons to select the creative experience; socio-professional situation; marital situation; net monthly income of the household; educational qualification; age; local shop behaviour and general evaluation of the experience. a cross-tabulation analysis was also carried out to test the association between sociodemographic and travel behaviour dimensions (i.e., first time at destination, information source and travel companions) with the cluster membership of respondents (tables 5 and 6 ). these analyses are presented in the next section. p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 4. results as a first stage of data analysis, an exploratory factor analysis was conducted to identify the dimensions of participants' motivation at creative tourism activities. both the kaiser-meyer-olkin (kmo) measure of sample adequacy (.801) and bartlett's test of sphericity (1202.103) results revealed that the data was properly fitted for principal component analysis and responses were factor analysed with varimax rotation. for factor extraction, the criteria of eigenvalues equal or above 1.0 was adopted, and factor loadings of at least .50 were accepted for item inclusion (hair, black, babin, anderson, & tatham, 2010) . none of the items presented low factor loadings (< .50), however "it is culturally motivating", "because of the location" and "i know the promoter of the activity" presented .536, .589 and .522, respectively evidencing a value only slightly higher than .50. results obtained a three-factor solution that accounted for 55.5% of the total variance ( table 2 ). the following names were attributed to the items attributed to each factor: creative; partners and family togetherness; and local community interaction. all factors had a sufficient reliability relying on cronbach's alpha coefficients ranging from .705 and .585. although two of the factors present a .60 value, according to hair et al. (2010, p. 124 ) the generally agreed upon lower limit for cronbach's alpha is .70, although it may decrease to .60 in exploratory research. a cluster analysis was applied to identify a collection of individuals, based on the detailed information obtained, in relatively homogeneous groups. finally, application of hierarchical clusters allowed patterns to be detected in individuals through categorical and continuous variables. in particular, the hierarchical clustering technique is a process that allows for the organization of data into nested groups (dash, liu, scheuermann, & tan, 2003) . in this way, categorical variables were added (reasons to select a creative tourism activity; socio-professional situation; marital status; educational qualifications; shop behaviour at local shops; general evaluation of the experience) as well as quantitative variables (counts) organized by groups (age and net monthly income of the household) in order to ascertain how many natural groups could be observed. a total of three groups were identified, with a total of 221 (33.6%), 211 (32.1%) and 225 (34.2%) obtained for groups 1, 2 and 3 respectively (table 3) . to identify statistically significant differences between the three-cluster solution, a kruskal-walis test was p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 applied and it shows that each group was different from each other. considering results from a one-sample t-test with a test value of 4 (table 4) , respondents evidenced a positive motivation towards creative tourism activities, except "to accompany someone" with a mean score of 3.19 (t-value = −13.589, p-value < 0.000) and "i know the promoter of the activity" with a mean score of 2.63 (tvalue = −20.156, p-value < 0.000). table 4 compares the motivations of each cluster and tables 5 and 6 show the profile of each group with respect to select demographic and travel behaviour characteristics. the clusters are described below according to their main characteristics. cluster 1 (novelty-seekers): this cluster includes 33.6% of the participants, with high motivations in the factor dimensions of creative (higher mean score-"it is original") and local community seekers (higher mean score -"it is culturally motivating"). in terms of sociodemographic characteristics, most are from the 18-35 years old group (37.4%) and the 36-53 years old group (34.2%) and, in terms of marital status, 61.8% are single and 29.7% are married, which means that they are mostly young individuals and middle-aged couples. they are well qualified, with bachelor degrees (39.5%) and postgraduate degrees (26.1%). considering the travel behaviour dimension, results reveal that individuals travelled with someone (73.2%): travelling with their child (27.6%), with an organized group (35.2%) or with friends (34.3%). within this cluster, 79.0% of the participants stated that the creative tourism activity was the primary reason for their visit. this group was named novelty-seekers because they tend to highly score on motivations which can be relevant to their engagement in actions of originality, fun and that stimulate creativity while, at the same time, they seek contact with other participants and with the local community. cluster 2 (knowledge and skills learners): this cluster includes 32.1% of the participants and it scored between the other two groups except in "to stimulate my creativity"; "it permitted interaction with other participants" and "i know the promoter of the activity". however, it is evident that with a higher score within the local community seekers factor (higher mean score -"it is culturally motivating") and in the creative factor (higher mean score -"it is original"), additionally and comparing with the group 1, this cluster presents a higher mean score within the socializers factor ("to accompany someone"). in terms of sociodemographic characteristics, most are aged between 18-35 years old (28.3%) and 36-53 years old (37.6%) and, in terms of marital status, 53.1% are single and 39.3% are married. they are well qualified, with bachelor degree (28.3%) and postgraduate degree (34.6%). considering the travel behaviour dimension, results reveal that individuals predominantly travelled with someone (90%): travelling with their spouse/partner (40.1%), with their children (40.0%) and with their family (42.6). within this cluster, 67.8% of participants indicated that this creative tourism activity was the primary reason of their visit to the locale. this group was named knowledge and skills learners because they tend to highly score motivations that imply their engagement in p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 actions of originality, fun, and to participate in creativity-stimulating activities together with their travel companions, while at the same time they seem to seek contact with the local community. cluster 3 (leisure creative-seekers): this cluster includes 34.2% of participants and scored high in every motivation, with the two higher mean scores in the local community seekers dimension ("it permitted interaction with other participants" and "it is culturally motivating"). middle-aged participants prevail (39.5%), but the young group of participants (18-35 years of age) also comprise an important percentage (30.5%) and the majority of individuals are single (54.9%). in terms of education, they are also qualified with a university degree (38.1%), but a considerable part of this group has high school education (33.5%). considering their travel behaviour, 83.8% travel with someone, and among those who travel with companions, 33.9% travel with spouse/partner and 36.5% with their family. the majority of participants indicated that this creative tourism activity was the primary reason for their visit (72.9%). this group was named leisure creative-seekers because they tend to highly score all motivations that imply their engagement in creative tourism activities is based on a perception of it as an educational and creative experience that can positively affect their emotions and stimulate them to activate their creative dimension during their travel experience. cluster 1 (novelty-seekers) and cluster 2 (knowledge and skills learners) consider "culturally motivating" as the most important motivator to select a creative tourism activity, whereas cluster 3 (leisure creative-seekers) consider "interaction with other participants" as the most important motivation. it is important to underline that "to accompany someone" is the least important motivation for cluster 1; however, this is one of the most important motivators for cluster 3. in the same vein, "i know the promoter of the activity" is the most important motivator for cluster 3, whereas for clusters 1 and 2 it is the least important motivator. these points highlight the main differences between each cluster concerning their motivations to select creative tourism experiences. overall, the sample is constituted by a considerable number of females (63.8%). in terms of marital status, 53.6% are single and 36.7% are married, and 63% are highly qualified with university degree (table 5) . within a professionally active age (78.9% aged between 18-65 years old), 23.4% are "specialists in intellectual and academic source: authors' elaboration. p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 activities", 13.8% are "technicians and associate professionals" and 9.4% are "managers/professionals". the household's net monthly income from employment is between 1001€ and 2500€ (43%). in terms of nationalities, 75.4% are from portugal and 24.6% are from foreign countries. in terms of travel companions, 25.2% travel with their partner, 24.3% travel with friends, 19.0% travel in an organized group, 16.1% travel as a family and 15.4% travel with their child(ren). for a considerable number of people this was the first time participating in a creative tourism experience (68.1%) and the creative tourism activity was the primary reason for visiting the destination (74.2%). the majority of participants learned about this experience through family and friends (33.2%), social networks (25.6%) and the website of the activity organizer (11.5%) (see table 6 ). this article aimed to characterize the profile of creative tourists and their motivations in portugal. the research sought to answer the following questions: who are the participants in creative tourism activities? what are the main motivations to attend a creative tourism activity? can motivation be used to segment creative tourism participants? the main focus of the study is to identify and articulate the profile of creative tourism participants based on their sociodemographic characteristics, travel behaviour and motivations. since the present study has an exploratory nature, in order to characterize the profile of these tourists, different groups of participants in creative tourism experiences were identified. although a few previous studies (in various countries) identified several features of creative tourists, none of them clearly identified groups of individuals based on sociodemographic characteristics, travel behaviour and motivations in a context of small and medium-sized cities and rural areas. also, they used a much smaller sample size than the one used in the current study. to validate the motivations-item scale and consequently to support the designation of the identified dimension factors and clusters, findings from a variety of studies were incorporated into the analysis, such as ryan and glendon (1998) about the application of the leisure motivation scale to tourism; tan et al.'s (2014) taxonomy of creative tourists; and the work on profiling creative tourists conducted by raymond (2003) , among others. the creative dimension factor was identified primarily based on the stated motivations about originality, fun and stimulation of the participant's creativity. this dimension partially corroborates with the characteristics of this form of tourism described by brouder (2012) , rudan (2012) and hung et al. (2016) . the partners and family togetherness dimension emerged as the factor linking participation in creative tourism activities with the need to share it with several types of travel companions, such as one's family. this dimension is grounded on ryan and glendon's (1998) research concerning the importance of the source: authors' elaboration. p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 item "be with others" to clarify the holiday motivation scale. furthermore, tan et al.'s (2014) taxonomy of creative tourists exerts the importance of items about "family togetherness" or to "take the opportunity to participate in an activity to be together with my family or friends". the local community interaction factor is the most relevant motivation that contains items similar to the studies by tan et al. (2014) , raymond (2003) and ryan and glendon (1998) . motivation items such as interaction with other participants; culturally motivated; and meet and interact with the local community are highly rated, corroborating these previous studies. following the identification of factor dimensions, a segmentation procedure was adopted based on sociodemographic, travel behaviour and motivation-based criteria. in the cluster analysis, a data-driven segmentation approach (dolnicar & grün, 2008; mazanec, 2000) was conducted that relied on analysing the data collected to determine market segment profiles. the results reveal that participants of creative tourism activities consist of three distinct clusters. a first cluster, called novelty-seekers, comprises a high involvement in creative motivation factors, such as looking for fun, originality and creativity, but also with an appreciative degree of socialization with other participants and with the local community in order to learn about its culture. this cluster meets a few of the characteristics of the typologies of crompton (1979) in what concerns motives to travel (push factors), particularly in the dimension of travel as a facilitator of social interaction. novelty-seekers are also framed into crompton (1979) , mainly in the dimension of travel to find novelty: "synonyms included curiosity, adventure, new and different. novel meant new experience but it did not necessarily mean entirely new knowledge" (p. 419). this segment corroborates also with tan et al.'s (2014) typology of the novelty-seekers perspective, mainly due to the attraction of new activities and searching for new "creative" activities. the second cluster, named knowledge and skills learners, comprises a high mean value inside three factor dimensions/ items: originality and culturally motivating, to accompany someone, and to meet and interact with the local community. this group is also characterized as the most academically qualified and more likely to travel with their family. previous studies about the profile of the creative tourist found evidence of these types of characteristics for tourists who stated they are motivated to participate in a creative tourism activity to gain knowledge (tan et al., 2014) . in the same vein, studies by richards (2014a) and smith (2016) also emphasized educational interaction with the community, similar to this knowledge and skills learners segment of creative tourists. the third segment, leisure creative-seekers, comprises participants who evidence a high mean value in all of the motivation items. however, if we consider the top three items, two of them are concentrated in local community interactors (interaction with other participants and culturally motivating) and the third is found in knowledge and skills learners (to accompany someone). it is also important to underline that this cluster classified all the motivation items highly (4 or above, in a 1 to 5 likert scale), which means that this cluster meets certain characteristics of the relax and leisure type of creative tourists found in the study by tan et al. (2014) but also follows mckercher, ho, du cros, and chow's (2002) cultural tourist typology, namely, the type of purposeful cultural tourist. the results also demonstrated an upgrade in several characteristics concerning the type of cultural tourists articulated by mckercher et al. (2002) . for instance, the leisure creative-seekers cluster highly ranked interaction with other participants and is motivated to participate in creative tourism activities to accompany someone, because it is original, because they know the promoter of the activity, and because it is suitable for the whole family. following from this, creative tourism participants considered to be leisure creative-seekers demonstrate a need to socialize and share the co-creation process with others during their experience. these results align with the conclusions of several studies concerning the tourist's involvement in the local culture through their participation in activities related with artefacts or other local products (e.g., anderson, 2009; cabeça, gonçalves, marques, & tavares, 2020; raymond, 2007; tan et al., 2013, among others) . creative tourism participants place great importance on co-creation in creative tourism activities, which involves processes involving tourists and residents as full participants and not passive subjects (binkhorst, 2008) . experiencing and interacting are key, with co-creation perceived as "a prerequisite for the definition of what a creative experience means and what it presupposes" (cabeça et al., 2020, p. 12) . finally, a brief remark on the sociodemographic and travel behaviour characteristics of the three clusters. as presented in tables 2 and 3 , only variables that present as statistically significant should be considered as features for each cluster. in all the clusters, the age dimension shows that more than 60% of creative tourism participants are between 18 and 53 years of age, a result that is concordant with results of studies conducted by raymond (2003) , campbell (2010) and chang et al. (2014) . in the same vein, education and marital status generally show similar results in all clusters. for instance, a considerable part of the three segments of creative tourists in this study are single and well educated, similar to the results gathered by tan et al. (2014) . in terms of their travel behaviour, in all clusters the tourists indicated that their primary reason to travel to that location was to participate in the creative tourism experience and almost all travel was accompanied. taking all this into account, creative tourism can be a strategic development priority for tourism and culture in portugal, especially in small cities and rural areas, and can be part of a tourism innovation model focused on local resources. there is a growing demand for local tourism products with higher added value, and interaction between participants and local residents as well as co-creation processes are key when choosing a destination. having these characteristics associated with it, creative tourism meets the diverse needs and motivations of contemporary travellers and can constitute a diverse offer, combining with various types of existing tourism (e.g., cultural tourism, nature tourism, gastronomic tourism). in order to improve the desired relations among the participants in creative experiences and with the local community, it is important to empower practitioners from the tourism and cultural/ creative sectors to collaborate as tourism experience providers as well as other community members who can act as local community facilitators. beyond the socio-demographic characteristics of these creative tourism participants, this study also analyzes motivational characteristics, finding them to be similar to those identified in other studies internationally. this study's results reinforce the importance of the interaction component, which is one of the main characteristics of creative tourism, that is, the socialization and interaction of the visitors with the local community and also among the participants themselves. understanding creative tourists' motivations enables promoters to develop activities that are more attractive and appropriate to meet travellers' expectations, thus constituting a more sustainable offer. in addition, the study introduces a strong element of desire for involvement in activities with one's travelling companions, that is, the search for creative tourism activities that promote activities for a family and/or among friends. the study results indicate a shift in creative tourism towards a more interactional dynamic in which the bonds between participants and cocreation processes are highly valued. placing emphasis on the interactional dimensions of creative tourism can amplify its meaning and prompt further research attention to the ways in which it materializes. this study aimed to better know the profile of the creative tourist because it has been widely recognized that there is no clear definition of the creative tourist at an international or national level (duxbury & richards, 2019b) . indeed, this is the first major study at the national or international level to investigate and segment the creative tourism market for activities in small and medium-sized cities and rural areas. beyond the socio-demographic characteristics of these creative p. remoaldo, et al. tourism management perspectives 36 (2020) 100746 tourism participants, this study also analyzes their motivational characteristics, finding them to be similar to those identified in other international studies. this study's results reinforced the importance of the interaction component, which is one of the main characteristics of creative tourism, that is, the socialization and interaction of visitors with the local community and also among the creative tourism participants themselves. in addition, the study introduces a strong element of involvement in activities among travelling companions, that is, a search for creative tourism activities that promote activities for a family and/or among friends. as with any other research, this study has some limitations that should be highlighted. a primary dimension of these limitations is related to the data and sample design. the sample has different weight sizes among the portuguese regions, focusing on the selected rural areas and small and medium-sized towns that are home to the creative tourism initiatives that were the focus of this research. the questionnaires were applied locally by the participating pilot organizations and centrally analyzed by the research teams. consequently, the adopted sample method was by convenience. a second dimension is concerned with the motivations listed in the questionnaire relating to the creative tourism activities. this research has an exploratory nature, and future studies should further explore and possibly identify other type of motivations based on qualitative research (such as adopting these items and other items tested in previous studies to conduct semistructured interviews with creative tourists) in order to test and validate a scale of creative tourism motivations. looking forward, future methodological research following from this study includes the need to validate a scale of motivations for participants in creative tourism activities. within the creatour project, it would be valuable to conduct further analysis of the creative tourism participant profiles and motivations data in relation to the different types of creative tourism activities in which the tourists were engaged. further additional quantitative and qualitative research involving international travellers would extend this research and also help to inform practitioners on how they can best prepare for and attract tourists to creative tourism activities based in small cities and rural areas. as the current study represents a snapshot of an emerging array of creative tourism initiatives in small cities and rural areas throughout continental portugal, it would also be valuable to extend this research over time so that a longitudinal perspective can be obtained as the initiatives develop, mature and evolve. as well, the extension of this research in a comparative framework involving creative tourism initiatives in other countries would be important to develop a more comparable data framework internationally for creative tourism. in the context of the covid-19 pandemic, creative tourism is well positioned to significantly contribute to post-pandemic tourism. creative tourism is, by nature, designed for small groups (e.g., families and social bubbles). it aligns well with the growing focus on domestic tourism and longer stays in one place -exploring one's city, region, or country with new perspectives on its diversities; pursuing personal interests and curiosities; and developing new skills. the nature of activities within creative tourism is diverse, and its transversality is also a key strength, complementing and extending the offers of other types of tourism (gonçalves, borges, duxbury, carvalho, & costa, 2020) . in smaller and rural communities, creative tourism can assist in providing activities for people staying for longer periods, and can be interconnected with nature and outdoors and restorative activities. the pandemic has also alerted us to the high degree of precariousness for workers in the tourism sector, the impacts of tourism on local communities and the importance of communities in the scope of tourism. altogether, there is a need to rethink tourism's traditional models. going forward, tourism-resident communities have to take a more active role in establishing tourism agendas and planning for their re-booted local development trajectories. this highlights another future research line -generative relations between tourism and local communities. from now on, it is clear that tourism will necessarily have to take the health and well-being of communities into account when determining tourism approaches and agendas, and to (re)consider how tourism brings benefits to communities. from this vantage point, creative tourism is also well positioned. as a widely applicable approach to place-sensitive tourism development (bakas, duxbury, silva, & vinagre de castro, 2020) , creative tourism can encourage and enable the diversification and differentiation of tourism offers in smaller places. the authors contributed equally to this work. influence of experiences on memories satisfaction and behavioral intentions: a study of creative tourism yester-morrow: using a region's heritage and culture for its economic future multivariate data analysis a creativity-led rural renaissance? amenity-led migration, the creative turn and the uneven development of rural australia connecting to place through creative tourism creative tourism dynamics: connecting travellers, communities, cultures, and places a influência das indústrias criativas sobre o turismo na cidade do porto. portugal: escola superior do porto creativity in tourism experiences: the case of sitges turismo de cocreación: valor añadido en escenarios turísticos agenda for co-creation tourism experience research creative tourism in bali's rural communities-examination of the current offer and advice 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crowds to creative tourism: a search for creative tourism in small and medium sized cities challenging "factor-cluster segmentation catalyzing creative tourism in small cities and rural areas in portugal: the creatour approach towards a research agenda for creative tourism: developments, diversity, and dynamics towards a research agenda for creative tourism: a synthesis of suggested future research trajectories open tourism: open innovation, crowdsourcing and co-creation challenging the tourism industry the rise of the creative class: and how it's transforming work, leisure, community and everyday life policy recommendations on creative tourism development in small cities and rural areas. coimbra: creatour project creative tourism in saint petersburg: the state of the art visita guiada à fábrica de antiguidades: sociologia, turismo e autenticidade. anais brasileiros de estudos turísticos multivariate data analysis detecting common method bias in predicting creative tourists' behavioural intention with an illustration of theory of planned behaviour creative experiences, memorability and revisit intention in creative tourism benefits of creative tourism-the tourist perspective facing the challenge? creative tourism in croatia greece as cultural destination. 16th international colloquium on regional sciences cultural tourism and world heritage creative tourism and cultural development: some trends and observations. paper presented at the cultural tourism conference, bonavista institute for cultural tourism marketing 3.0: produits, clients, facteurshumains creative tourism: a global conversation market segmentation activities-based segmentation of the cultural tourism market creative tourism experiences in guimarães: a twofold analysis of visitors' and suppliers' perspectives changes in consumer behaviour -the challenges for providers of tourist services in the destination mindful visitors: heritage and tourism criatividade: a construção de novos cenários para o turismo em ponte de lima defining cultural tourism. international conference on civil, architecture and sustainable development (casd-2016) creative tourism magazine tourist experiences and academic junctures creative tourism business model and its application in bulgaria prosuming creative urban areas: evidence from east london tourism research-critiques and challenges the importance of lifestyle entrepreneurship: a conceptual study of the tourism industry welcome to the experience economy the future of competition: co-creating unique value with customers creative tourism supply: creating culturally empathetic destinations visitor experiences in cultural spaces the cultural creatives: how 50 million people are changing the world cultural renewal + tourism: case study-creative tourism creative tourism new zealand: the practical challenges of developing creative tourism lisbon: sílabo o legado de guimarães capital europeia da cultura de 2012. a leitura dos residentes e dos visitantes good and not-so-good practices in creative tourism networks and platforms: an international review management practices in creative tourism: narratives by managers from international institutions to a more sustainable form of tourism changes in the guimarães visitors' profile and the city attributes perceptions in the post hosting of the 2012 european capital of culture geo-crowdsourcing contributions for cultural mapping cultural tourism research methods. amsterdam: great britain by tj international creative tourism: a global conversation tourism development trajectories: from culture to creativity? tourism & management studies creativity and tourism: the state of the art creativity and tourism in the city development of experiences in creative tourism creative tourism developing creativity in tourist experiences: a solution to the serial reproduction of culture? tourism management tourism, creativity and development razvojne perspective kretivnoga turizma hrvatske application of leisure motivation scale to tourism estudo macroeconómico desenvolvimento de um cluster de indústrias criativas na região do cultural tourism and business opportunities for museums and heritage sites issues in cultural tourism studies issues in cultural tourism studies creativity, tourism and economic development in a rural context: the case of prince edward county a model of creative experience in creative tourism a taxonomy of creative tourists in creative tourism the third wave interaction between cultural/creative tourism and tourism/cultural heritage industries mass tourism, culture and the historic city: theoretical perspectives urban tourism and the politic of creative class: a study of the chefs in macao this research was conducted within the project creatour, "creative tourism destination development in small cities and rural areas" (project 16437), which is funded by the portuguese foundation for science and technology (fct/mec) through national funds and cofunded by feder through the joint activities programme of compete 2020 and the regional operational programmes of lisbon and algarve. key: cord-304375-l5gvpat3 authors: singh, kamaljit; kaur, hardeep; chibale, kelly; balzarini, jan; little, susan; bharatam, prasad v. title: 2-aminopyrimidine based 4-aminoquinoline anti-plasmodial agents. synthesis, biological activity, structure–activity relationship and mode of action studies date: 2012-03-13 journal: eur j med chem doi: 10.1016/j.ejmech.2012.03.007 sha: doc_id: 304375 cord_uid: l5gvpat3 2-aminopyrimidine based 4-aminoquinolines were synthesized using an efficacious protocol. some of the compounds showed in vitro anti-plasmodial activity against drug-sensitive cq(s) (3d7) and drug-resistant cq(r) (k1) strains of plasmodium falciparum in the nm range. in particular, 5-isopropyloxycarbonyl-6-methyl-4-(2-nitrophenyl)-2-[(7-chloroquinolin-4-ylamino)butylamino] pyrimidine depicted the lowest ic(50) (3.6 nm) value (56-fold less than cq) against cq(r) strain. structure–activity profile and binding with heme, μ-oxo-heme have been studied. binding assays with dna revealed better binding with target parasite type at rich puc18 dna. most compounds were somewhat cytotoxic, but especially cytostatic. molecular docking analysis with pf dhfr allowed identification of stabilizing interactions. faced with the challenges of drug resistance, poor health systems, lack of affordable, safe and convenient treatment options, efficient treatment of malaria, one of the most devastating parasitic diseases, represents an unmet medical need. malaria is a major public health concern in more than 90 countries inhabited by more than 2.4 billion people e 40% of the world's population and is responsible for almost 1 million deaths every year [1] . the majority of malaria victims in developing countries are pregnant women or children under the age of five, possessing little or no immunological protection. the disease is estimated to result in w250 million new annual infections worldwide. though the majority of the cases and approximately 90% of the malaria deaths are found in sub-saharan africa, the disease is now increasing in asia and latin america. malaria is caused by protozoan parasites of the genus plasmodium that infects and destroys red blood cells eventually leading to death, if untreated. the persistent threat of emergence of multidrug resistant plasmodium falciparum, universal chloroquine resistance [2, 3] , suspected resistance to artemisinins [4, 5] , and lack of effective, appropriate and affordable treatment options have given a new impetus to the research leading to broadening of the range of therapeutic targets. thus, creating a new armamentarium of drugs with promising antimalarial activity coupled with understanding of their mode of action may lead to the development of a new generation of treatments both for malaria control and eradication. the common feature of the drugs based on quinine 1 is the presence of a quinoline unit, usually a 7-chloroquinoline (chloroquine 2 and amodiaquine 3, chart 1), and are known to cause parasite death by blocking the polymerization of the toxic heme, into an insoluble and non-toxic pigment, hemozoin, resulting in cell lysis and parasite cell autodigestion [6e8] . the mode of action of 2,4-diaminopyrimidine based drugs, typified by pyrimethamine 4 [9] and the lead compound wr99210 5 [10] is through the inhibition of p. falciparum dihydrofolate reductase (pf dhfr) enzyme, required for the biosynthesis of tetrahydrofolate involved in the biotransformation of thymidylate synthase-catalysed deoxyuridylate to deoxythymidylate (dump / dtmp), through a methyl group transfer reaction during dna biosynthesis [11e16] . in addition, a number of polyamines inhibit ornithine decarboxylase activity in p. falciparum through binding with plasmodial dna [17, 18] . recently, investigations in hybrid antimalarial agents, combining 4-aminoquinoline with other pharmacophore having antimalarial activity have been found to be less prone to resistance to parasite and has thus offered an effective means to overcome the problem of drug resistance. we envisaged that linking 7-chloro-4-aminoquinoline unit, critical for antimalarial activity through a diversely functionalized lateral side chain with other antimalarial moiety such as aminopyrimidine, might furnish conjugate hybrids [19] capable of showing useful antimalarial activity. in this communication, we report synthesis of a set of compounds that possess basic, hydrophobic as well as hydrogen bonding substituents, required for targeting either or both heme as well as dna, thus providing new antimalarial agents active against chloroquine resistant strains of p. falciparum. we have evaluated their anti-plasmodial activity, cytotoxicity and cytostatic activity, binding studies with dna and heme (monomeric as well as m-oxo dimeric) using uvevisible, fluorescence spectrophotometry as well as nmr analysis. compounds 10aes were synthesized as outlined in scheme 1, via a common intermediate 8. 3,4-dihydropyrimidin-2(1h)-ones 6 were prepared through hcl-catalyzed biginelli condensation of appropriate aldehyde (r 3 cho), alkylacetoacetate (r 2 ch 2 coor 1 ) and urea [20] . dehydrogenation of 6 using pyridinium chlorochromate in dcm furnished pyrimidinones 7 [21] . refluxing 7 with pocl 3 yielded 8 which upon nucleophilic substitution reaction with appropriate 4-amino-7-chloroquinoline 9 gave 10aes in a synthetically useful manner [22] . structures of 6e10 were established on the basis of spectral ( 1 h nmr, 13 c nmr, ms, ft ir) as well as microanalytical analysis. the yields of the 2-aminopyrimidines 10 are reported in table 1 . antiplasmodial activity of pyrimidines linked to cq as in 10 has not been described in literature albeit the related dihydropyrimidin-2(1h)-ones (dhpms) have previously been reported [23] . using the synthetic protocol shown in scheme 1 allowed considerable diversification around the pyrimidine core for conducting sar analysis. the in vitro anti-plasmodial activities of 10aes were determined in primary and secondary screening against cq s and cq r strains of p. falciparum. the half maximal inhibitory concentration (ic 50 ) of 10aes are summarised in table 2 (fig. 1) . evidently, the compounds have anti-plasmodial activity in the nm range and against the cq r strain of p. falciparum, in some cases activity was found to be even superior to cq. systematic variation of the length as well as nature of the spacer connecting the pharmacophores discerned useful trends in the anti-plasmodial activity of these analogs. comparing 10aeg, bearing linear alkyl spacers, revealed an increase in the anti-plasmodial activity with increase in length of the spacer up to 4 methylene groups (10ae10c, table 2 ). further lengthening of the spacer chain length resulted in significant reduction in activity against both the cq r as well as the cq s strains. replacing the c-4 phenyl group in 10c by a methyl group to create 10m resulted in nearly 5 times increase in anti-plasmodial activity (ic 50 42.1 nm) against the cq s strain. in fact, compound 10m was found (table 2) to be the most active compound of the series, against the cq s strain. however, 10m exhibited a high resistance factor (w39) within the series but is 3.5 times less active than cq, against the cq r strain. replacement of the ethyl ester with isopropyl ester (10nes), in general showed a decrease in in vitro antiplasmodial activity against the cq s strain, although a reverse trend was observed for the cq r strain, especially in case of 10s, 10p and 10r, where replacing c-4 phenyl by p-nitrophenyl (10s) or onitrophenyl (10p and 10r) groups, in addition to incorporating an isopropyl ester, resulted in an increase of activity in that order, rendering 10r as the most potent (ic 50 3.6 nm, 56 times more potent than cq, table 2 ) of all these compounds. these results are in accordance with the trend observed in case of n, n-bis(7chloroquinolin-4-yl)alkane diamines, wherein the alkyl spacer consisting of four carbon atoms showed optimum potency [24] . the better anti-plasmodial activity of phenyl-substituted pyrimidine compounds against the cq r strain may be attributed to optimal fitting of these compounds in the active site of pfdhfr leading to a favorable conformation for p-p interaction with the heme functionality. moreover, the introduction of a nitro substituent on the phenyl ring at the c-4 position of the pyrimidine core results in a significant increase in anti-plasmodial activity as well as resistance against the cq r strain, although it has little effect on activities against the cq s strain (table 2) . also, the corresponding o-, m-or p-nitro derivatives showed considerable variation in antiplasmodial activity ( table 2 ). comparison of compounds (10n, 10q, 10s) having an identical spacer reveals that the p-no 2 substituted 10s (ic 50 175.8 nm) is more active than the o-/m-no 2 substituted compounds 10q and 10n, respectively, but are less active than the unsubstituted ethyl ester analog 10b. further, comparison with the butyl spacer analog suggests that o-no 2 phenyl derivative 10r is more potent than the m-no 2 counterpart 10o, as well as its ethyl ester analog 10c, against the cq r strain. compound 10r was found to be the most active compound in this series against the cq r strain with anti-plasmodial activity (ic 50 3.6 nm), 56 times more than cq (ic 50 201.8 nm) and comparable to artesunate (ic 50 2.8 nm) ( table 2) . comparing 10j (ic 50 28096.7 nm) possessing the branched chain spacers with identical carbon linear spacer analog 10b (ic 50 52.2 nm, table 2 ) led to significant decrease in activity. thus, compound 10j displayed a 540-fold decrease in activity compared to 10b, against the cq r strain. likewise, 10k possessing a branched c-6 spacer depicted a decrease (ic 50 860.4 nm, table 2 ) in activity against linear alkyl (c-7) spacer analog 10d (table 2 ), but higher than 10j. comparing 10j and 10k, with branched chain spacers, not only was the anti-plasmodial activity of the latter against both cq s and cq r strains increased, but it also showed an increased resistance factor ( table 2 ). the replacement of linear chain spacers with o-and p-linked aryl groups (10h and 10i, respectively), led to much higher ic 50 (table 2 ) values compared to former against cq r strain, while only moderate activity was observed in case of 10i against cq s strain. these findings could be attributed to the increased steric bulk (10h more than 10i) affecting the interaction of the iron center of heme with the compounds. this has been corroborated by performing the titration of monomeric heme with both 10h and 10i. 1:4 molar ratio of heme and 10i. hence, the flexibility, chain length and steric constraints of the spacer linking quinoline moiety and pyrimidine unit seem to play a role in anti-plasmodial activity of these derivatives. although the in vitro activity of 10aec, 10p and especially 10r (ic 50 3.6 nm) was superior to cq (ic 50 201.8 nm) against the cq r strain, these compounds suffer from high clogp values (table 2) , which are suggestive of the fact that these possess limited aqueous solubility, which in fact is not a serious limitation in view of recent advancements in formulation methods. antiviral activity of the compounds 10aec, 10len, 10p and 10r, which were active against the cq r strain was also evaluated against (i) parainfluenza-3 virus, reovirus-1, sindbis virus, coxsackie virus b4, punta toro virus in vero cell cultures, (ii) herpes simplex virus à1 (hsv-1; kos), herpes simplex virus-2 (hsv-2; g), vaccinia virus, vesicular stomatitis virus, herpes simplex virus-1 (tk à kos acv r ), cytomegalovirus, varicella-zoster virus in hel cell cultures, (iii) vesicular stomatitis virus, coxsackie virus b4, respiratory syncytial virus in hela cell cultures, (iv) influenza a virus (h1n1 and h3n2) and influenza b virus in mdck cell cultures and (v) feline corona virus (fipv) and feline herpes virus activity in crfk cell cultures (si tables s1es7). unfortunately, no significant antiviral activity was noted at subtoxic concentrations. most compounds were somewhat cytotoxic to the different cell lines (confluent nonproliferating cultures), but especially cytostatic against proliferating (vero/mdck/crfk) cell cultures. chloroquine has been shown to inhibit hiv through blockade of viral entry via inhibition of endosomal acidification [25, 26] . compounds 10aec, len, p, r were also tested against hiv-1 as well as hiv-2 (si table s8 ) in human t-lymphocyte (cem) cell cultures. however, none of the compounds were active at subtoxic concentrations. generally, the compounds exhibit a relatively high cytostatic activity but displayed a fairly safe selectivity index (except 10m and 10n) ( table 2 ) in the range of 10.04e638 against mdck cell cultures. the most active compound 10r with an ic 50 value of 3.6 nm against cq r strain exhibited a highest selectivity index (si ¼ 638), 10l with an ic 50 value of 160.8 nm against cq r strain exhibited a high selectivity index (361.9). however, 10m having an ic 50 value of 1659.8 nm was most toxic with a selectivity index of 0.48. the plausible mechanism of in vitro anti-plasmodial action against cq r strain has been investigated for 10c and 10r, found to be most potent of the series of the compounds reported herein (ic 50 26.1 nm, 10c and ic 50 3.6 nm, 10r). these compounds are also expected to bind to heme [fe(iii)ppix] (hydroxo or aqua complex of ferriprotoporphyrin ix) in solution and inhibit aggregation to bhematin, in much the same way as cq itself. the higher clogp values ( table 2 ) of these compounds being higher than cq necessitated the use of aqueous dmso as solvent. also in 40% aqueous dmso solution, heme is expected to be monomeric, while in purely aqueous solutions, it exists in aggregated form. further, it is known that cq binds to heme dimer (m-oxo heme) in vitro and can also inhibit the formation of b-hematin, the in vitro analog of hemozoin [27e30] . therefore the binding assay was also extended to heme dimer also. the interaction of 10c and 10r with monomeric heme was followed by spectrophotometric titration at ph 7.4 and 5.6 (the approximate ph of food vacuole), as described previously [31] . the spectral changes (fig. 3a , si figure s1 ), upon addition of increasing amounts (0e70 mm) of 10r to a solution of heme (2.4 mm, hepes buffer ph 7.4) showed substantial decrease of intensity of the fe(iii) ppix soret band at 402 nm with no shift in the absorption maximum. the longer wavelength q-bands (494 and 537 nm) of the metalloporphyrin also decrease in intensity (si figure s2 ) [32] . a sharp isosbestic point was observed at 416 nm (ph 7.4) and at 412 nm (ph 5.6). the association constants for the complexes formed between monomeric fe (iii) ppix and 10r at ph 7.5 and 5.6 were calculated from titration data and are presented in table 3 . the association constant of 10c ( fig. 2a ) is found to be greater (log k 6.018) than 10r (log k 5.078). decrease in the apparent ph from 7.5 to 5.6 caused a fairly modest decrease in log k values of both 10c and 10r, indicating a strong binding to heme even at acidic ph. the binding of 10c and 10r was also assessed from their 1 h nmr titration with heme. thus, while 1 h nmr spectrum of 10r depicted considerable broadening of signals under the conditions (40% dmso-d 6 in d 2 o) of recording and was inconclusive, the variation in the chemical shift in signals corresponding to quinoline unit of 10c were clear (fig. 4 ), upon addition of heme. a 1:1 stoichiometry of the most stable complexes of both 10r and 10c with monomeric heme at ph 7.5 and 5.6 was deduced from the job's plot (si figure s3 ) [33, 34] . the absorbance at 402 nm got to maximum when mole fraction of 10r approached 0.5. this is in good agreement with the association constant (log k) values corresponding to the most stable 1:1:heme: 10r species present in solution, obtained by fitting the titration data in hyp spec -a nonlinear least square fitting programme. the measured log k values for both 10r and 10c (table 3) are also in good agreement with the values reported in literature for cq [32, 35, 36] . thus, the formation of synthetic fe(iii)ppix-10r complex, as demonstrated above is suggestive of inhibition of formation of b-hematin and presumably results in anti-plasmodial activity of these compounds in a fashion similar to that of cq. titration of constant concentrations of heme in aqueous naoh solution at the physiological ph 5.8 of plasmodial food vacuole [35] allowed understanding of the interaction of 10r and 10c with m-oxo heme. with addition of increasing amount of 10r to the solution of m-oxo heme, the absorbance of soret band (362 nm) decreased appreciably with significant red shift (362e405 nm, fig. 5a ). the association constants and stoichiometry for both 10r and 10c were determined from titration data and are presented in table 3 .the calculated association constant of 10r (log k 6.31) is greater than 10c (log k 6.09) and corresponds to 1:1 stoichiometry of the 10r:moxo heme complex. the comparison of association constants of 10r and 10c for monomeric and m-oxo heme reveals that both compounds bind strongly with m-oxo heme than monomeric heme and inhibit hemozoin formation by blocking the growing face of heme resulting in the observed anti-plasmodial activity. further, all the compounds were also screened for in vitro inhibition of bhematin formation using b-hematin inhibitory assay in order to further confirm their mechanism of action based on interference with the heme detoxification process [37, 38] . as shown in table 4 , there is a general correlation between antiplasmodial activity and inhibition of b-hematin formation, but the same generalisation does not hold for compound 10h, as, in spite of having 100% b-hematin inhibition (table 4) , it is one of the least active (ic 50 27320.9 nm, cq r and ic 50 14828.3 nm, cq s ) compounds of the series. however, it must be noted that anti-plasmodial activity not only depends upon the b-hematin inhibition but also on other factors such as degree of accumulation of drug in food vacuole. further, 10r showed dose dependent inhibition of bhematin formation (si figure s4 ) with an ic 50 value lower than those reported for cq and quinine, thus demonstrating a better ability to interact with fe(iii)ppix. overall, these compounds showed strong b-hematin inhibition which seems to be their preferred mode of action. dna binding has been considered previously as one of the possible mechanisms for anti-plasmodial activity and has been studied using spectrophotometry [39] , spectrofluorimetry [40] , dna melting [41] , viscometry [42] etc. recently, some 4aminoquinoline derivatives have been shown to interact with dna [37] presumably through ionic interactions between phosphate groups of dna and protonated amine sites resulting in stabilization of the helical configuration of dna against thermal denaturation [41, 43] . additionally, interactions between aromatic nucleuses of the drug with nucleotide bases might also contribute. binding of the plasmid dna with cq resulted in the elevation of the thermal melting temperature (t m ) of dna in addition to other effects [44e47]. we therefore investigated the binding of the most active of the series, 10c and 10r toward gc rich calf thymus dna (ct dna) as well as at rich puc18 dna through stepwise addition of small increments of dna to a solution the compounds at constant concentration as well as physiological ph (fig. 6a and b) . a progressive decrease in the characteristic quinoline ring absorptions at 320 and 340 nm attributable to the intercalation of the quinoline into dna was indicated. the isosbestic point at 350 nm indicated that the spectra of limiting systems (i.e. the spectra of free and completely bound drug) intersect and permitted the selection of a single wavelength for study of complex formation. the binding constant (log k: 10c 4.67 and 10r 3.39) was calculated from benesiehildebrand equation [48] and suggested strong interaction with ct dna. comparison of binding constants reveals that 10c binds 20 times more strongly with ct dna than 10r. altering the dna base composition to see its effect on the drug binding, we studied the interaction of 10r with gc rich ct dna by fluorometric titration. the emission band at 380 nm of 10r (fig. 7) , decreases in intensity with increasing concentration and eventually gets completely quenched. the binding constant (log k) calculated from the fluorescence data is 4.67. similar titration with at rich puc18 dna (log k ¼ 5.27) revealed higher affinity of 10r toward at rich puc18 dna unlike cq which is known to interact strongly with gc rich dna [46] . the strong interaction of the pyrimidine analog with at rich puc18 dna further suggests that these compounds might target parasite dna which has unusually a high at content [47] in addition to b-hematin inhibition. the binding of ligand to nucleic acid of dna (especially at rich dna) may possibly induce conformational changes depending upon the strength and mode of its interaction with nucleic acids and thus result in increase in the thermal denaturation temperature, as observed for cq. groove binding or electrostatic binding of the phosphate backbone of dna gives rise to small changes in thermal denaturation temperature compared to the intercalation pathway due to stabilization of watson crick base paired duplex [43, 48, 49, 50] . in the direction of evaluating strength of interaction of 10c and 10r with dna, the thermal behavior (si figure s5 ) of ct dna in the presence of drug was evaluated. the thermal denaturation temperature of ct dna (60 c), in the presence of 10c and 10r recorded an increase in dt m of 3 c and 2.5 c, respectively (si table s9 ), suggesting primary groove binding and/or partial intercalative nature of the interaction. many of the anti-plasmodial agents are known to interact with pf dhfr for their anti-plasmodial activity. especially table 2 in vitro anti-plasmodial activity, cytotoxicity, resistance factor and selectivity index of compounds 10a-s. ic 50 pyrimethamine (chart 1) is known to produce anti-plasmodial effect by binding to pf dhfr. the best known lead compound for this inhibitory activity is wr99210 (5) . it is worth comparing the performance of the compounds designed in this work with that of 5, using molecular docking methods. the crystal structure (pdb id: 1j3i, a structure of wild-type pf dhfr-ts complexed with wr99210, nadph, dump) was considered for molecular docking analysis. after appropriately preparing the protein structure of pf dhfr, docking of 5 and 10r were carried out. fig. 8 shows the top scoring binding pose of 10r in the active site of pf dhfr. the docking score for 10r is à24.5, which is much better than that of the lead compound 5 (à20.1). the origin of this improvement in docking score can be traced to the increased number of stabilizing interactions between 10r and pf dhfr, in comparison to the interactions between 5 and pf dhfr. 10r shows hydrogen bonding interaction with tyr170 and asn108 residues; these two interactions are common to 10r as well as to 5. in addition, 10r shows hydrogen bonding interaction with ser111 and leu46 residues. these additional stabilizing interactions ensure that 10r adopts a slightly different (and improved) pose in comparison to that of 5. these improved interactions can be considered as deterministic factors for the improved anti-plasmodial activity of 10r. an efficacious transformation for converting readily available 3, 4-dihydropyrimidinones (dhpms) to 2-aminopyrimidine based 4aminoquinolines is presented. the compounds showed anti-plasmodial activity identical to or superior to cq. structureeactivity relationship has been drawn leading to the identification of at least one compound 10r as lead compound in this series. the tested compounds did not depict any antiviral activity and were cytotoxic. binding interaction of representative potent compounds with heme and m-oxo heme using uvevisible and nmr experiments furnished log k values identical with cq binding and pointed to 1:1 stoichiometry of the most stable complexes in solution. dna (both gc and at rich) binding affinity using absorption and spectrofluorometric data indicated stronger interaction of 10c (20 fold) than 10r with ct dna, however, 10r showed higher affinity toward at rich puc18 dna suggesting targeting of parasite at rich dna by 10r in addition to b-hematin inhibition as possible mode of action of these compounds. dna melting experiments suggested primary groove binding and/or partial intercalative nature of interaction of 10c and 10r with ct dna. thus, the strong electrostatic interaction of newly designed pyrimidine analogs with at rich dna and blockage of heme polymerisation by complexation of drug with heme contribute to the observed antimalarial activity in nano molar range. further, molecular docking analysis of 10r in the active site of pf dhfr indicated superior binding compared to wr99210. thus, drug 10r acts on multiple targets (heme, enzyme involved in biosynthesis of dna (dhfr), parasite dna) which accounts for its high anti-plasmodial activity. all liquid reagents were dried/purified following recommended drying agents and/or distilled over 4 å molecular sieves. thf was dried (na-benzophenone ketyl) under nitrogen. 1 h nmr (300 mhz) and 13 c (75 mhz) nmr spectra were recorded in cdcl 3 on a multinuclear jeol ft-al-300 spectrometer with chemical shifts being reported in parts per million (d) relative to internal tetramethylsilane (tms, d 0.0, 1 h nmr) or chloroform (cdcl 3 , d 77.0, 13 c nmr). mass spectra were recorded from indian institute of integrative medicine (csir), jammu, under electron impact at 70 ev on a bruker daltonics esquire 3000 spectrometer. elemental analysis was performed on flash ea 112 (thermo electron corporation) analyzer at department of chemistry, guru nanak dev university, amritsar and the results are quoted in %. ir recorded on ftir shimadzu 8400 fourier-transform spectrophotometer in the range 400e4000 cm à1 using chloroform as medium. melting points were determined in open capillaries and are uncorrected. for monitoring the progress of a reaction and for comparison purpose, thin layer chromatography (tlc) was performed on precoated aluminum sheets merck (60f 254 , 0.2 mm) using an appropriate solvent system. the chromatograms were visualized under uv light. for column chromatography silica gel (60e120 mesh) was employed and eluents were ethyl acetate/hexane or ethyl acetate/ methanol mixtures. to the stirred solution of 8 (2 mmol) and potassium carbonate (5 mmol) in dry thf (30 ml), a solution of appropriate 4aminoquinoline 9 (1.0 mmol) in dry thf (50 ml) was added. the reaction mixture was stirred for 48 h at room temperature. the reaction mixture was filtered and thf was removed under vacuum. the residue was purified by column chromatography using meoh/ etoac as eluent to obtain corresponding 10, which was recrystallized from dcm/hexane. using this procedure the following compounds were isolated. to the stirred solution of appropriate 4-aminoquinoline 9 in dry thf (50 ml) mixture of 8 (in a 1:2 molar ratio) and potassium carbonate in dry acetonitrile was added. the reaction mixture was refluxed for 48 h and then filtered. acetonitrile was removed under vacuum and the residue was purified by column chromatography using etoac/hexane as eluent to give 10h and 10i which were recrystallized from dcm/hexane. yellow solid. rf: 0.9 (70% hexane/etoac two clones of p. falciparum are used: (a) 3d7 clone of nf54 which is known to be sensitive to all anti-plasmodials, (b) k1 strain originating from thailand that is resistant to chloroquine and pyrimethamine, but sensitive to mefloquine. the cultures were naturally asynchronous (65e75% ring stage) and were maintained in continuous log phase growth in rpmi1640 medium supplemented with 5% washed human aþ erythrocytes, 25 mm hepes, 32 nm nahco 3 , and albumaxii (lipid-rich bovine serum albumin) (gibco, grand island, ny) (cm). all cultures and assays are conducted at 37 c under an atmosphere of 5% co 2 and 5% o 2 , with a balance of n 2 . stock drug solutions were prepared in 100% dmso (dimethylsulfoxide) at 20 mg/ml. the compound was further diluted to the appropriate concentration using complete medium rpmi1640 supplemented with 15 nm cold hypoxanthine and albumaxii. assays were performed in sterile 96-well microtitre plates; each plate contained 100 ml of parasite culture (0.5% parasitemia, 2.5% hematocrit). each compound was tested in triplicate and parasite growth compared to control and blank (uninfected erythtocytes) wells. after 24 h of incubation at 37 c, 3.7 bq of [ 3 h] hypoxanthine is added to each well [51] . cultures were incubated for a further 24 h before they are harvested onto glass-fiber filter mats. the radioactivity was counted using a wallac microbeta 1450 scintillation counter. the results were recorded as counts per minute (cpm) per well at each drug concentration, control and blank wells. percentage inhibition was calculated from comparison to blank and control wells, and ic 50 values calculated using graph pad prism 4.0. the preliminary screen uses the 3d7 strain. the compounds were tested at 6 concentrations (30, 10, 3, 1, 0.3, and 0.1 mg/ml). if the compound did not affect parasite growth at 10 mg/ ml it was classified as inactive, between 10 and 1 mg/ml, the compound was designated as partially active, and if <1 mg/ml, the compound was classified as active and was further evaluated by three-fold serial dilutions in a repeat test. for secondary screening both the 3d7 clone and the k1 line were used. the compound was diluted three-fold over at 12 different concentrations with an appropriate starting concentration based on the preliminary screen. the ic 50 is determined by a sigmoidal dose response analysis using graph pad prism 4.0. for each assay, the ic 50 and ic 90 values for each parasite line were determined against the known anti-plasmodials chloroquine and artesunate. the antiviral assays [except anti-human immunodeficiency virus (hiv) assays] were based on inhibition of virus-induced cytopathicity in hel [herpes simplex virus type 1 (hsv-1), hsv-2 (g), vaccinia virus, and vesicular stomatitis virus], vero (parainfluenza-3, reovirus-1, coxsackie b4, and punta toro virus), hela (vesicular stomatitis virus, coxsackie virus b4, and respiratory syncytial virus) and mdck (influenza a (h1n1; h3n2) and b virus) cell cultures. confluent cell cultures in microtiter 96-well plates were inoculated with 100 cell culture inhibitory dose-50 (ccid 50 ) of virus (1 ccid 50 being the virus dose to infect 50% of the cell cultures) in the presence of varying concentrations of the test compounds. viral cytopathicity was recorded as soon as it reached completion in the control virus-infected cell cultures that were not treated with the test compounds. the anti-hiv activity and antiproliferative activity were evaluated against hiv-1 strain iiib and hiv-2 strain rod in human t-lymphocyte cem cell cultures. briefly, virus stocks were titrated in cem cells and expressed as the 50% cell culture infective dose (ccid 50 ). cem cells were suspended in culture medium at w3 â 10 5 cells/ml and infected with hiv at w100 ccid 50 . immediately after viral exposure, 100 ml of the cell suspension was placed in each well of a flat-bottomed microtiter plate containing various concentrations of the test compounds. after a 4-day incubation period at 37 c, the giant cell formation was microscopically determined. compounds were tested in parallel for cytostatic activity in uninfected cem cells. binding stoichiometries of drug with monomeric & m-oxo dimeric heme were monitored by uvevisible spectrophotometry using job's method of continuous variation [33, 34] . the concentration of drug & heme in solution was kept constant and changes in absorbance at 402 nm (monomeric)/362 nm (dimeric) were monitored as a function of the mole fraction. 96 well plate containing mixture of 50 ml of 0.5 mg\ml of hemin chloride dissolved in dmso, 100 ml of 0.5 m sodium acetate buffer (ph 4.4) and 50 ml of different concentrations of drug solution or 50 ml of solvent (control), was incubated at 37 c for 24 h. the plate was centrifuged at 4500 rpm for 3 min, and supernatant was discarded. the remaining pellet was re-suspended with 200 ml of dmso to eliminate unreacted hemin [38, 39] . the plate was centrifuged again and supernatant similarly discarded. the precipitate was dissolved in 150 ml of 0.1 n naoh & absorbance was read at 405 nm. the percentage of inhibition of ferriprotoporphyrin ix biomineralisation was calculated using formula: inhibitionð%þ ¼ 100xf½ðabs of controlþ à ðabs of drugþ= ðabs of controlþg. ic 50 values were determined by using graph pad prism 4.0. 6.4. dna binding studies with 10c and 10r stock solution of 10c and 10r (2 mm) were prepared in ar grade methanol. the dna binding experiments were carried out by making dilution of the stock with 1:1 buffered methanol. stock solution of dna was prepared by dissolving dna pellet in te buffer (10 mm trisehcl, 0.1 mm edta, ph 7.4). the dna concentration was estimated from its absorbance intensity at 260 nm with a known molar absorption coefficient value of 6600 dm 3 mol à1 cm à1 . the purity of dna was established from ratio of absorbance intensity at 260 nm and at 280 nm. the observed ratio of 1.8 ensured that dna was free from protein. 260 nm at various temperature in the presence and absence of drug in a 5:1 ratio of the dna and drug with a ramp rate of 0.5 c/min in a 40% dmso/te buffer (ph 7.4) with 0.5 mm nacl on a shimadzu 1601 pc spectrophotometer equipped with a peltier thermo regulator. the thermal melting temperature was calculated by plotting da/dt vs temperature using microsoft excel. the molecular docking analysis was carried out using flexx molecular docking module [52, 53] (flexx 1.13.5) available in the sybyl 7.1 software package from tripose [54].this docking approach adopts an incremental construction algorithm for identifying appropriate pose of the substrate in the active site of the enzyme. it generates about 30 possible poses of the substrate in the active site. most of the 30 poses obtained in this analysis adopted similar binding mode in the enzyme cavity and hence the top scoring pose was considered in this analysis. to perform the above analysis, the crystal structure 1j3i (wild-type plasmodium falciparum dihydrofolate reductase-thymidylate synthase (pfdhfr-ts) complexed with wr99210, nadph, and dump) was downloaded from the protein data bank [55] (pdb) and subjected to protein preparation and receptor description [56] . the structures of the substrates were prepared by first building the molecules in 3d and optimizing the structures using tripos force field. the ionic, tautomeric states of substrates were considered while performing molecular docking analysis. the pose shown in fig. 7 includes the neutral state of the substrate in the active site of the enzyme. yield: 65%. ir (kbr): n max 772, 1270, 1700, 2998, 3300 cm à1 1 h (300 mhz 26 ( s, 16h, ch 2 ), 1.57 (d, j ¼ 6.9 hz, 2h, ch 2 ), 1.71 (d, j ¼ 6.9 hz, 2h, ch 2 ), 2.48 (s, 3h for c 35 h 44 n 5 o 2 cl: c, 69 .96; n, 11.45. ms: m/z 602 (m þ ) yield: 58%. ir (kbr): n max 716, 1127, 1700, 2940, 3446 cm à1 1 h (300 mhz 5-ethoxycarbonyl-6-methyl-4-phenyl-2-[5-(7-chloroquinolin-4-ylamino)-2-methylpentylamino] pyrimidine (10k) viscous liquid. rf: 0.6 (8% meoh/etoac) white solid 44 (s, 6h, c6 & c4ech 3 ), 3.44 (q, j ¼ 6.0 hz, 2h, ch 2 ), 3.67 (q, j ¼ 6.3 hz, 2h, ch 2 ), 4.36 (q, j ¼ 7.2 hz, 2h h, 5.93; n, 16.63. ms: m/z 413.5 (m þ ) white solid 41 (s, 6h, c6 & c4ech 3 ), 3.40 (q, j ¼ 6.9 hz, 2h, ch 2 ), 3.57 (q, j ¼ 6.0 hz, 2h .15; n, 15.99. ms: m/z 428.1 (m þ ) -ylamino)propyl amino]pyrimidine (10n) yellow solid. rf: 0.6 (2% meoh/etoac) 13 c nmr (75 mhz ylamino)butylamino] pyrimidine (10o) yellow solid. rf: 0.6 (5% meoh/etoac) 55 (s, 3h ylamino)ethylamino] pyrimidine (10p) yellow solid 67 (s, 3h -ylamino)propyl amino] pyrimidine (10q) yellow solid. rf: 0.6 (10% meoh/etoac) 57 (s, 3h, c6ech 3 ), 3.19 (br, 2h, ch 2 ), 3.41 (q, j ¼ 5.4 hz, 2h ylamino)butylamino] pyrimidine (10r) yellow solid. rf: 0.6 (5% meoh/etoac) 57 (s, 3h, c6ech 3 ), 3.13 (br, 1h, nh), 3.30 (m, 2h n, 15.25. ms: m/z 548.1 (m þ ) -ylamino)propyl amino] pyrimidine (10s) yellow solid new medicines to improve control and contribute to the eradication of malaria chloroquine transport via the malaria parasite's chloroquine resistance transporter plasmodium chloroquine resistance and the search for a replacement antimalarial drug artimesinin resistance in plasmodium falciparum malaria artimesinin-resistant malaria in asia falcipain-2 inhibitors quinoline antimalarial: mechanisms of action and resistance discovery of dual function acridones as a new antimalarial chemotype a pre-emptive strike against malaria's stealthy hepatic forms modelling and informatics in the analysis of p. falciparum dhfr enzyme inhibitors effects of pyrimethamine, chlorguanidine and primaquine against exoerythrocytic forms of a strain of chloroquine-resistant plasmodium falciparum from thailand 8-quinolinamines and their pro-drug conjugates as potent bloodschizontocidal antimalarial agents synthesis of 4-pyrido-6-aryl-2-substituted amino pyrimidines as a new class of antimalarial agents new antimalarial drugs a bifunctional thymidylate synthetase-dihydrofolate reductase in protozoa mechanism based inhibitors of deoxythymidine monophosphate synthesis as antineoplastic agents plasmodium berghei: inhibitors of ornithine decarboxylase block exoerythrocytic schizogony interaction of pyrimethamine, cycloguanil, wr99210 and their analogues with plasmodium falciparum dihydrofolate reductase: structural basis of antifolate resistance recent developments in the design and synthesis of hybrid molecules based on aminoquinoline ring and their antiplasmodial evaluation aldureids of ethylic acetoacetate and ethylic oxaloacetate an efficacious protocol for the oxidation of 3, 4-dihydropyrimidin-2(1h)-ones using pyridinium chlorochromate as catalyst facile transformation of 3,4-dihydropyrimidin-2(1h)-ones to pyrimidines in vitro evaluation as inhibitor of myobacterium tuberculosis and modulators of cytostatic activity synthesis, antimalarial and cytotoxic evaluation of reversed chloroquines based on the 3, 4-dihydropyrimidi-2(1h)-one scaffold -chloroquinolin-4-yl) alkanediamines with potential against chloroquine-resistant malaria chloroquine and hydroxychloroquine as inhibitors of human immunodeficiency virus (hiv-1) activity effects of chloroquine on viral infections: an old drug against today's diseases? an assessment of drug-haematin binding as a mechanism for inhibition of haematin polymerisation by quinoline antimalarials interactions of quinoline antimalarials with hematin in solution quinoline antimalarials decrease the rate of betahematin formation ferriprotoporphyrin ix fulfills the criteria for identification as the chloroquine receptor of malaria parasites thermodynamic factor controlling the interaction of quinoline antimalarial drugs with ferriprotoporphyrin ix structure-function relationships in aminoquinolines: effect of amino and chloro groups on quinoline-hematin complex formation, inhibition of b-hematin formation, and antiplasmodial activity application of jobs method of continuous variation to stoichiometry of protein-ligand complexes determination of binding stoichiometry by the continuous variation method-the job plot chloroquine analogues: influence of side chain length and quinolyl nitrogen pk a on activity vs chloroquine resistant malaria a spectroscopic investigation of the binding interaction between 4, 5-dihydroxyxanthone and heme new bis (2-aminoimidazoline) and bisguanidine dna minor groove binders with potent in vivo antitrypanosomal and antiplasmodial activity a non-radiolabelled ferriprotoporphyrin ix biomineralisation inhibition test for the high throughput screening of antimalarial compounds the interaction of chloroquine with nucleic acids and nucleoproteins interaction of the antimalarial drug fluoroquine with dna, trna, and poly-(a): 19 f-nmr chemical-shift and relaxation, optical absorption, and fluorescence studies dna: reaction with chloroquine reaction between dna and quinacridine and other antimalarials spectroscopic studies on the thermodynamic and thermal denaturation of the ct-dna binding of methylene blue structure-function correlation of chloroquine and analogues as transgene expression enhancers in nonviral gene delivery the genome of plasmodium falciparum i: dna base composition sequence preference of chloroquine binding to dna and prevention of z-dna formation pharmacogenomic analyses of targeting the at-rich malaria parasite genome with at-specific alkylating drugs a spectrophotometric investigation of the interaction of iodine with aromatic hydrocarbons spectrophotometric studies of the interaction of chloroquine with deoxyribonucleic acid antimalarial versus cytotoxic properties of dual drugs derived from 4-aminoquinolines and mannich bases: interaction with dna quantitative assessment of antimalarial activity in vitro by a semiautomated microdilution technique multiple automatic base selection: proteinligand docking based on incremental construction without manual intervention a fast flexible docking method using an incremental construction algorithm insights into antifolate resistance from malarial dhfr-ts structures a common feature-based 3d-pharmacophore model generation and virtual screening: identification of potential pfdhfr inhibitors key: cord-276166-b1e0bbrp authors: li, shi-fang; zhao, fu-rong; shao, jun-jun; xie, yin-li; chang, hui-yun; zhang, yong-guang title: interferon-omega: current status in clinical applications date: 2017-10-12 journal: int immunopharmacol doi: 10.1016/j.intimp.2017.08.028 sha: doc_id: 276166 cord_uid: b1e0bbrp since 1985, interferon (ifn)-ω, a type i ifn, has been identified in many animals, but not canines and mice. it has been demonstrated to have antiviral, anti-proliferation, and antitumor activities that are similar to those of ifn-α. to date, ifn-ω has been explored as a treatment option for some diseases or viral infections in humans and other animals. studies have revealed that human ifn-ω displays antitumor activities in some models of human cancer cells and that it can be used to diagnose some diseases. while recombinant feline ifn-ω has been licensed in several countries for treating canine parvovirus, feline leukemia virus, and feline immunodeficiency virus infections, it also exhibits a certain efficacy when used to treat other viral infections or diseases. this review examines the known biological activity of ifn-ω and its clinical applications. we expect that the information provided in this review will stimulate further studies of ifn-ω as a therapeutic agent. interferons (ifns) were first reported by isaacs and lindenmann as antiviral proteins that are generated by cells in response to viral infection [1, 2] . ifns are composed of three subgroups: type i, type ii, and type iii ifns. the type i ifns, including ifn-α, ifn-β, ifn-ε, ifn-ω, ifnκ, ifn-δ, ifn-τ, and ifn-ζ, exert biological activity through common receptors (interferon-α/β receptor 1 [ifnar1] and ifnar2) [3, 4] . type ii ifn, namely ifn-γ, is produced by t lymphocytes and natural killer cells in response to the recognition of infected cells [5] . type iii ifns consist of ifn-λ1, ifn-λ2, and ifn-λ3, which regulate the immune response via a distinct receptor complex that uses a signaling pathway that is similar to that of type i ifns [6, 7] . ifn-ω genes were first found in humans in 1985 [8, 9] . ifn-ω diverged from the ifn-α gene approximately 130 million years ago, and it is produced primarily in leukocytes [10] . human ifn-ω genes include four pseudogenes and one full gene that is expressed in leukocytes, and human ifn-ω shares 62% amino acid sequence homology and similar functions with ifn-α, and 33% amino acid similarity with ifn-β [11] . similar to other ifns, ifn-ω is also produced by cells in response to viral infection, and it has biological activities because it binds to the same receptors and activates a pathway that is similar to that activated by ifnar [12] , while the activation of phosphoinositide-3-kinase/ protein kinase b (p13k/akt) signaling is also vital for biological responses mediated by ifn-ω [13] . however, its antigenic structure is distantly related to ifn-α, -β, and -λ, as it does not cross-react with antibodies against them [14] . as a result, treatment with ifn-ω can be effective for patients who are resistant to ifn-α [15] . although ifn-ω has been studied extensively, our knowledge of ifn-ω is still limited compared with that of interferon ifn-α and -β. here, we provide a broad review of what is known about the biological activities and potential clinical application of ifn-ω. overall, we hope that the information provided in this review will stimulate further studies of ifnω as a therapeutic agent. until now, ifn-ω has been identified in humans [8] , felines [16] , pigs [17] , horses [18] , rabbits [19] , serotine bats [20] , cattle [21] , and sheep [22] , while it has not been found in canines and mice [21] ; however, the characteristics of ifn-ω differ in different species. the characteristics of ifn-ω from different species are summarized in table 1 . despite such differences, there are common characteristics that exist in these species. generally, ifn-ω genes are intronless, and nglycosylation sites (not present in felines) and transcription factor binding sites, such as irfs, isres, and nf-κb, are present in the promoter regions of these genes [9, 10, 20, 30] . in addition, all mammalian ifn-ω genes lack the proline codon that precedes the final conserved cysteine codon [24] . the ifn-ω protein contains several conserved residues, such as arginine at position 161, cysteine residues at positions 1 and 99 and 100, seven prolines (four of which are located at positions 4, 26, 39, and 117 of the mature protein), while positions 29 and 139 and 140 form two disulfide bonds. these residues are present at similar locations in type i ifns, and they are vital for their biological activity [33] . other conserved structural motifs, such as the regions between amino acid residues 29-41, 71-82, and 123-142, are highly conserved among ifn-α proteins, and they play a key role in the biological activity of ifn-ω [26, 28, 29] . in addition to having a structure that is similar to that of type i ifns, ifn-ω also displays the same physicochemical characteristics as type i ifns, such as high sensitivity to trypsin, insensitivity to temperature, and stability at ph 2 [28, 29] . some studies revealed that ifn-ω loses its antiviral activities after being treated with 0.25% trypsin. however, it retains high antiviral activity against vesicular stomatitis virus after exposure to ph 2 for 24 h at temperatures ranging from 42°c to 63°c [26, 28, 29] . based on analyses of phylogenetic trees obtained from alignments of the ifn-ω protein sequences from these mammal species, it was proposed that all these proteins evolved from a common ancestor [20, 28] . type i ifns, including ifn-ω and ifn-α, display a common mechanism of action. ifns interact with specific cell-surface receptors, and then the expression of ifn-stimulated genes (isgs) is induced, some of which encode antiviral effectors or molecules, such as signaling proteins, transcription factors, and apoptotic proteins, while chemokines further regulate ifn signaling and other host responses in a positive or negative manner [28] . ifn-ω is not an exception. it has been proposed that ifn-ω shares antiviral activities with ifn-α because it binds to the same type i ifn receptor complex. studies have revealed that ifn-ω induces the transcription of the mx1, isg15, ifit3, and isg56 genes [20, 28] . however, different from ifn-α, it shows certain degrees of cross-species activity; therefore, ifns could exhibit different physiological functions in the host. for example, bovine ifn-ω (boifn-ω) protects madin-darby bovine kidney cells, primary embryo bovine lung table 1 ifn-ω in different species and the characteristics of the ifn-ω gene and protein. location characteristics of the ifn-ω gene and protein reference human human chromosome 9 human ifn-ω has at least five members, but only one member of the human ifn-ω family is a functional gene that results in a functional and glycosylated protein. this protein has six additional amino acids located at its carboxyl-terminus (172 amino acid residues) and a single polypeptide chain comprising two disulfide bonds and an n-glycosylation-linked site at amino acid 80. in terms of the primary structures of the type i ifns, there is approximately 75% amino acid sequence identity between ifn-α and ifn-ω. [8, 9, 12, 15, 23] cat no data felines ifn-ω (feifn-ω) includes 13 subtypes that contain an amino-terminal secretory signal sequence from residues 1-23. the mature sequence of ifn-ω contains four highly conserved cysteines (positions 1, 29, 100, and 140) and seven prolines (four of those at positions 4, 26, 39, and 117 of the mature protein), while the feifn-ω protein has six additional amino acids at its carboxyl-terminus compared with feifn-α. among these subtypes, feifn-ω2 and feifn-ω4 contain a seven-amino-acid insertion at position 109, and the insert location is comparable to that of the feifn-α, while it has higher antiviral activity than the other subtypes. interestingly, different from that in other mammalian subtypes, these 13 subtypes do not have an n-glycosylation recognition site. [16, 24] pig chromosome 1 porcine ifn-ω (poifn-ω) contains seven or eight members with variable open reading frame lengths. the most extensive similarity of the poifn-ω sequences are to bovine leukocyte ifn-ω, and the lowest one is to equine ifn-ω. it contains an ifabd functional domain, multiple putative binding sites for type i ifn receptor subunits, and one putative nglycosylation site (asn/asp-x-ser/thr). the subtypes of the ifn-ω protein, which have five alpha-helices, bear aminoterminal 20-to 30-amino-acid signal peptides and four conserved cysteine residues, cys24, cys52, cys122, and cys162, which are also found in ifn-α1. in addition, all ifn-ω subtypes, except ifn-ω1 (whose carboxyl-terminus is 11 residues shorter than the other poifn-ω subtypes), have 14 or 16 extended residues, while the pairs ifn-ω2/6 and ifn-ω3/5 share identical sequences. [17, 25, 26] horse chromosome 23 horse ifn-ω contains eight members plus four pseudogenes, which is a greater than the number of ifn-α genes and more diverse than the other type i ifn genes. the ifn-ω gene contains a putative glycosylation sequence, asn-thr-thr, at positions 78-80. the ifn-ω protein has six alpha-helices and it contains ifabd (cd00095), interferon (pfam00143), and ifabd (smart00076) domains, and multiple putative binding sites for the type i ifn receptor subunit 1 and 2 and an nglycosylation site. notably, the length of the open reading frame of each ifn-ω subtype is invariant. [18, 27] rabbit no data the rabbit ifn-ω family comprises at least eight genes that display the highest degree of homology with human ifn-ω and the lowest with murine ifn-αii. there are two irf-1 binding sites at nucleotide positions 85 and 55, the hexamer repeat sequence 5′-gaaann-3′ in the 5′ noncoding sequence, and a repetition of the 5′-ttatttat-3′ motif, which is similar to many 3′ downstream regions of genes encoding inflammatory cytokines. in addition, the immediate promoter region of the rabbit ifn-ω genes has a high proportion of purine residues. an atg sequence, (5′-gaaatg-3′), was found only in the promoter region of rbifnw48 at nucleotide position 66. similarly, ifn-ω includes four cys residues at amino acid positions 1, 29, 99, and 139. [19] cattle chromosome 8q15 the ifn-ω family in cattle (boifn-ω) consists of 24 members that contain two pseudogenes and 22 functional genes. among these subtypes, the nucleotide similarity is 91.3%-97.2%, and the amino acid identity is 84.4%-95.4%. most of these subtypes encode 195 amino acids, expect boifn-ω7 and boifn-ω11, which lack nine amino acid residues at their carboxyl terminus. in addition, 23 cells, feline kidney cells, porcine kidney cells, rabbit kidney cells, and primary bovine testicular cells from vesicular stomatitis virus challenge. however, the antiviral activities of boifn-ω are low in madin-darby bovine kidney cells, but high in porcine kidney and bovine testicular cells. additionally, no protective effects were found on madin-darby bovine kidney cells and baby hamster kidney cells [28, 29] . these results suggest that cells have a tendency to be insensitive to ifnω from distantly related species. the antiviral activities of ifn-ω also vary with the subtypes and viral strain used in challenges. in a previous study, the expression of poifn-ω2/-ω6, poifn-ω3/-ω5, and poifn-ω8 were upregulated, while poifn-ω1 (which has 11 fewer residues at its carboxyl terminus than the other poifn-ω subtypes) was not detected in porcine kidney cells challenged with pseudorabies virus or poly (i):poly(c). interestingly, the level of poifn-ω1 also increased when peripheral blood mononuclear cells were challenged with pseudorabies virus, and poifn-ω2/-ω6 was upregulated the most in these studies [26] . similarly, recombinant serotine bats ifn-ω can inhibit european bat lyssavirus type 1, european bat lyssavirus type 2, and rabies virus replication in a dose-dependent manner, and different biological activities were elicited (in the order of european bat lyssavirus type 1 < rabies virus < european bat lyssavirus type 2) [20] . the antiviral activities of ifn-ω have also been compared to those of other ifns. when a549 cells were respectively treated with ifn-ω and type i and type iii ifns, the cells treated with ifn-ω at a concentration of 10 ng/ml obviously repressed the replication of influenza a virus in a dose-dependent manner, and it resulted in larger reductions in viral titers, compared with those obtained with ifn-α2 [34] . however, its activity was much lower than the activity of ifn-β1, and it was slightly lower than the activities of ifn-λ1 and ifn-λ2. depending on the dose, pretreating caco-2 cells with human ifn-ω significantly reduced the loads of the h1n1 influenza virus [35] . interestingly, ifn-β and ifn-ω showed similar inhibitory activity against both ca/04 and bj/501 influenza viruses at every concentration tested. in addition, both were significantly more potent than ifn-α as far as the inhibitory effects on both stains at a given concentration. in addition to its in vitro activities, ifn-ω has been demonstrated to have antiviral activity in vivo as well. for example, a robust induction of mx mrna and the oas-1a protein was found in animals treated by ifn-ω compared with controls [35] . furthermore, following daily intravenous treatment with human ifn-ω (huifn-ω), the viral load of h1n1 influenza virus decreased significantly in the lung tissues of guinea pigs, and ifn-ω exhibited an identical inhibitory effect against the ca/04 influenza virus compared with ifn-α [35] . although ifn-ω has demonstrated promising antiviral activity against some viral infections in vivo and vitro, several factors could limit its antiviral efficacy, such as poor pharmacokinetics and a short half-life [36] . pegylation, a covalent conjugation of nontoxic polyethylene glycol (peg), has been demonstrated to improve the plasma half-life of a therapeutic protein and decrease its proteolytic sensitivity [37] . recently, yu et al. [38] found that pegylation improved the poor pharmacokinetics of recombinant huifn-ω (rhuifn-ω), despite the fact that its antiviral activity was decreased to some extent. it is worth noting that the bioactivity of pegylated rhuifn-ω was determined by examining its pegylation sites, in which residues at the amino-terminus had higher activities compared with those of residues lys 134 and lys 152 , while the poor pharmacokinetics were determined by the conjugated peg mass. in a previous study, amino-terminally pegylated rhuifn-ω with 40 kda of linear peg, which exhibited 21.7% of the rhuifn-ω biological activity with a half-life of 139.6 h, allowed some viral diseases to be treated by fewer doses at longer dosing intervals [38] . the use of human igg1 fc fusion proteins has also been demonstrated to be a simple and effective method for prolonging serum half-life [39] . some studies showed that compared with rhuifn-ω expressed in yeast with a specific activity of 7 × 10 7 iu/mg, rhuifn-ω-fc had a lower activity of 1.6 × 10 7 iu/mg when it was expressed in chinese hamster ovary cells. furthermore, the terminal half-life of rhuifn-ω-fc was 35-fold higher than that of rhuifn-ω, and it exhibited better pharmacokinetics characteristics [40] . perhaps rhuifn-ω-fc will become a new alternative antiviral drug for the treatment of chronic viral infections. several studies also revealed that glycosylation has an essential effect on the activity of ifns [41] , and glycosylated ifn-ω was more potent than ifn-ω against bovine viral diarrhea virus, yellow fever virus, and west nile virus [41, 42] . a possible explanation for its potency is that glycosylated ifn-ω could induce the activation of the sterol regulatory element binding transcription factor, the activating enhancer binding protein 2-like yy1 site, the interferon consensus sequence binding protein, the erythroid kruppel-like factor gene, the homeotic gene forkhead of drosophila 8/hepatocyte nuclear factor 3/ mouse forkhead lung protein, hnf-1α, the interferon conserved sequence-binding protein, and the lymphocyte-enriched dna binding protein lyf, which are not induced by ifn-α [41] . glycosylated ifn-ω also exhibits good clinical applications. previous studies showed that glycosylated ifn-ω + ribavirin (rbv) had a synergistic effect in terms of its antiviral activity in hepatitis c virus (hcv)-infected patients [43] . similarly, a synergy of the antiviral effects of glycosylated ifnω + rbv against bovine viral diarrhea virus was also obtained. interestingly, an antagonism of the cytotoxic effects of rbv by glycosylated ifn-ω was observed [43] . thus, the combination of glycosylated ifn-ω and rbv appears to be favorable for the synergy of antiviral activities and the antagonism of the cytotoxic effects of rbv. increasing evidence suggests that ifn-ω may be associated with the nonspecific immune response based on increased survival time, the presence of acute-phase proteins (serum amyloid-a, α-1-glycoprotein, and the c-reactive protein), the phagocytic activities of whole blood cells and macrophages, natural killer cell activities, and reduced concurrent viral excretion [44] [45] [46] [47] [48] . in general, increasing the number of isgs, mx proteins, and zaps, which could enhance pathogen detection and innate immune signaling, indicates that ifn-ω elicits an immune response. when cells are treated with ifn-ω, mx-1, isg15, ifit3, and isg56 expression was upregulated in a dose-dependent or time-dependent manner [20, 29] . more recently, studies from leal et al. [49] showed that interleukin (il)-6 production was affected considerably in feline immunodeficiency virus (fiv)-infected cats treated with recombinant feline ifn-ω (rfeifn-ω) by subcutaneous or oral protocols. specifically, il-6 plasma levels decreased and proviral loads increased in fiv-cats treated subcutaneously with rfeifn-ω, while il-6 mrna expression decreased in the oral group. however, the therapy did not affect viremia and the expression of other cytokines (il-1, il-4, il-10, il-12p40, ifn-γ, and tumor necrosis factor-α) [49] . thus, ifn-ω appears to be involved in innate immunity, and it could further inhibit viral replication and exert its antiviral activity. ifns have been demonstrated to have antiproliferative effects as a result of inducing cell-cycle arrest and apoptosis, which are independent pathways [50] . similar to ifn-α, ifn-ω also inhibits cell proliferation in a dose-dependent manner [20, 29] . however, ifn-α exhibits a higher antiproliferative activity than ifn-ω at elevated concentrations [29] . ifn-ω also exhibits antitumor activity in vitro in a cell-specific manner. feline mammary carcinomas are among the most common feline tumors, and they represent an important cause of mortality. when used to treat feline and canine mammary carcinoma cells and derived putative tumor-initiating cells, rfeifn-ω exhibited a dose-dependent, species-specific, target cell-specific action, and an additive effect was observed between rfeifn-ω and conventional anticancer drugs such as mitoxantrone, doxorubicin, and vincristine [51] . thus, rfeifn-ω may be used as a therapeutic agent in feline and canine mammary carcinomas. there is evidence showing that gene transfer would allow one to take advantage of the beneficial effects of type i ifns without their undesirable side effects [52] . for instance, huifnβ gene lipofection produces an equal or even superior effect than that of high doses of exogenously applied huifnβ protein. recently, a study conducted by villaverde et al. [52] demonstrated that felines feifn-ω gene lipofection exhibited an equal or higher cytotoxic effect than rfeifn-ω. this kind of effect was due to the induction of reactive oxygen species generation, mitochondrial membrane potential disruption, and calcium uptake, indicating that ffeifn-ω lipofection is an alternative approach for treating both sensitive and resistant phenotypes with an equal or superior outcome and with fewer adverse effects than recombinant ffeifn-ω therapy [52] . similarly, injecting the gene encoding interferon ω1 via the tail vein into mice bearing a hep-a-22 liver tumor via liposomal gene delivery also significantly decreased tumor weights [53] . interestingly, this effect was greater (43% tumor inhibition) only when the plasmid contained human thymosin alpha 1 [53] . a dna ladder (a hallmark of cells undergoing apoptosis) was observed in the tumor cells treated by ifn-ω. interestingly, the antitumor mechanisms involve increasing the expression of tα1 and ifn-ω, and a plasmid-liposome complex of ifn-ω and ifn-α together exerted greater potency in inhibiting the growth of hep-a-22 tumor cells than either compound alone [53] . because of its antiviral, immunomodulatory, anti-proliferation, and antitumor activities, ifn-ω has been explored as a treatment option for some diseases and viral infections in humans and other animals. huifnω displays antitumor effects in several models of human cancer in vivo. in addition, it has also been used to diagnose some diseases [54, 55] . when produced in silkworm larvae using a baculovirus vector that includes the feifn-ω sequence, rfeifn-ω, as an immunomodulator, has been registered in many countries (e.g., japan, australia, new zealand, and mexico) to treat canine parvovirus, feline leukemia virus (felv), and fiv infections (http://emea.europa.eu) [45, 56] . despite the fact that it is not licensed to treat other viral infections, it exhibits efficacy when used to treat other viral infections such as bovine enterovirus, infectious bovine rhinotracheitis virus, bovine viral diarrhea virus, vesicular stomatitis virus, pseudorabies virus, european bat lyssavirus, influenza virus, feline calicivirus (fcv), and feline herpesvirus-1 (fhv-1) [20, 28, 34, 57] . the rfeifn-ω licensed protocol consists of three therapeutic cycles of five daily subcutaneous injections (1 mu/kg), beginning respectively on days 0, 14, and 60 [58] . however, its widespread use is limited because this protocol is relatively expensive and time-consuming. some alternative subcutaneous and topical protocols, such as oral and intralesional administration, have been suggested [59, 60] . interestingly, no adverse effects were found in cats treated with rfeifn-ω following mucosal administration [58, 61] , while subcutaneous administration was accompanied by some mild adverse effects (e.g., fever, lethargy, vomiting, and diarrhea) in some trials [46] . thus, rfeifn-ω could become an option for treatment in veterinary clinical practice. hcv is a major public health problem with approximately 170 million infections worldwide [62] . many hcv-infected individuals cannot eliminate the virus, and persistent infection with hcv causes chronic liver disease, including cirrhosis and hepatocellular carcinoma [63, 64] . until now, a combination of ifn-α and rbv has been the standard of care for chronic hcv infections [65, 66] . however, it has many deleterious side effects. furthermore, some hcv chronic carriers are not suitable for this therapy, and new antiviral approaches are needed. some studies showed that ifn-ω was equally effective at inhibiting hcv replication compared to ifn-α and ifn-β. interestingly, the combinations of ifn-ω and ifn-α or ifn-β exhibited primarily antagonistic interactions [67] . in addition, other studies showed that the activity of non-glycosylated ifn-ω was comparable to that of ifn-α, while glycosylated ifn-ω was more potent in repressing hcv rna replicons. thus, ifn-ω can be used as a prospective antiviral candidate for the treatment of hcv infections [41] . in addition to being a potential therapy for hcv, ifn-ω could also be used to diagnose some human diseases. aps-1 is a monogenic disease that is caused by mutations in the autoimmune regulator (aire) gene [68, 69] . currently, many autoantibodies, including those targeting aromatic acid decarboxylase, tyrosine hydroxylase, nacht leucine-rich repeat protein 5, tryptophan hydroxylase, and ifn-ω, have been found in aps-1 patients [55] . a study has shown an anti-ifn-ω antibody was highly prevalent in aps-1 patients with mutated aire alleles, even though the presence of anti-ifn-ω antibodies preceded aps-1 clinical symptoms and the development of other autoantibodies [70] . therefore, antibodies against ifn-ω have become an essential diagnostic tool for aps-1. numerous available assays, such as immunoassays, radioligand binding assays, and antiviral neutralization assays, were designed to detect anti-ifn-ω antibodies [70] [71] [72] . however, all of them have drawbacks, including a lack of sensitivity, the use of radioisotopes, the requirement for facilities to grow viral cultures, as well as being time-consuming. some novels diagnosed methods were also developed. zhang et al. [73] reported that an ipa based on 125 i-labeled ifn-ω showed higher sensitivity to aps-1 than other anti-type 1 ifn antibodies when 48 aps-1 patients were examined. similar to the study by zhang et al., 48 aps-1 patients were also investigated in a study by oftedal et al. [74] , and these patients were also positive for anti-ifn-ω antibodies, as determined by an ipa based on 35 s-labeled ifn-ω, which also exhibit a greater correlation to aps-1 than other anti-type 1 ifn antibodies. these results suggest that out of the spectrum of anti-type 1 ifn antibodies, testing for anti-ifn-ω antibodies is more suitable for patients suspected of having aps-1. recently, larosa et al. [75] developed a novel, highly sensitive, and specific assay to measure anti-ifn-ω antibodies. they found that 125 i-labeled ifn-ω and 35 s assays resulted in 5/6 and 1/6 discrepant samples, respectively, which agrees with aire gene results [75] . regarding the measurement of anti-ifn-ω antibodies in the studied patients, the 125 i assay seems to have a better performance, as it is disease-specific, more reliable, and more precise than the 35 s assay, making it possible to assess patients with aps-1 and patients suspected of having aps-1 prior to an aire gene analysis. fcv, a member of the caliciviridae family, is an important and common pathogen for cats, which is characterized by clinical signs ranging from mild and severe oral ulcerations or upper respiratory tract disease to a severe fatal systemic disease [76, 77] . unfortunately, there are still no direct-acting antiviral drugs for the treatment of fcv. previous studies demonstrated that rfeifn-ω had a positive therapeutic effect in fcv-infected cats in some experiments or trials [46, 57, 78] . combination antiviral therapy has become a common practice. recently, researchers revealed that a combination treatment of rfeifn-ω and mefloquine resulted in additive effects with a reduction in the half maximal inhibitory concentration [79] . another study conducted by lee et al. [80] showed that the relative expression of ifn-ω, mx, and zaps mrna in crandell-reese feline kidney cells was upregulated significantly in fcv-infected cats. interestingly, after the cats were pretreated with a korean red ginseng (krg) extract or ginsenosides, the expression of these genes was higher than that in the group treated with fcv alone [80] . it is desirable to find a combination of a krg extract or ginsenosides and ifn-ω that effectively treats fcv-infected cats. because of its similar structural characteristics and genomic structure, fcv could be a representative human norovirus surrogate [81] ; thus, these therapies could also be used to treat human norovirus infections. fhv-1, a double-stranded dna virus that replicates in the nucleus of host cells and produces intranuclear inclusion bodies, is one of the foremost causes of feline upper respiratory tract disease [82] . it has been demonstrated that rfeifn-ω has a dose-dependent inhibitory effect on the replication of fhv-1 in vitro [83] . several studies showed conflicting results about the biological activity of rfeifn-ω against these two viruses in cats. for instance, 160 cats suffering from fcvassociated feline upper respiratory tract disease were treated with an intravenous dose of 2.5 or 5 mu/kg rfeifn-ω three times per day every other day [82] . while improved clinical signs were detected within 7 days, no control group was used in this study. in another study, 20 cats with fhv-1-associated ocular keratitis were treated five times per day with a dose of 0.5 mu/ml rfeifn-ω, and although a significant improvement of ocular signs was observed after 3 weeks of treatment, no control group was included [83] . in 2007, using a placebo as a control group, the effect of rfeifn-ω in cats that were pretreated with rfeifn-ω before challenge with fhv-1 was investigated [84] . unexpectedly, no beneficial effects were observed in these cats. ballin et al. [85] reported a similar finding; they found that compared to a control group treated with a placebo, cats treated with rfeifn-ω did not exhibit improved clinical signs of acute viral feline upper respiratory tract disease despite having lower fcv copy numbers than cats receiving rfeifn-ω [85] . more studies are needed to verify that rfeifn-ω has a therapeutic effect in vivo. felv, an endogenous retrovirus that belongs to the genus gammaretrovirus of the family retroviridae causes a variety of degenerative and immunosuppressive disorders such as severe anorexia, cachexia, and progressive weakness [86, 87] . studies indicated that rfeifn-ω affects the felv cycle at the post-transcriptional level. however, it did not alter protein synthesis [88] . treatment with rfeifn-ω lowered reverse transcriptase activity, which is used to evaluate the amount of infectious viral particles, in a dose-dependent manner in felv-infected fl74 cells [88] . furthermore, according to the half maximal inhibitory concentration, rfeifn-ω was more potent than rhuifn-α in inhibiting reverse transcriptase activity. in addition, this study showed that ifn-ω decreased the viability of felv-infected fl74 cells and increased apoptosis and mortality in infected cells [88] . fiv is a feline lentivirus that was first described in 1987, and many studies have focused on it because its complex genomic and immunopathogenic features that are similar to those of human immunodeficiency virus [89, 90] . furthermore, fiv coinfection was found to occur in 7% of felv-infected cats [91] . previous studies showed that rfeifn-ω significantly decreased clinical scores and rates of mortality, and improved abnormal hematologic parameters (red blood cell count, packed cell volume, and white blood cell count) in virus-infected cats [45] . these studies demonstrated that rfeifn-ω had significant therapeutic effects on clinical signs. evidence also showed that an effective immune modulation in fiv-cats could be obtained by treating them orally with rfeifn-ω. in a previous study [45] , fiv-infected cats that were orally administered rfeifn-ω at a dose of 0.1 mu/cat gained weight, although no dramatic changes were obtained regarding viral loads and the cd4 + /cd8 + ratio. however, this study did not assess any clinical benefits [45] . recently, oral protocols were also used to administer rfeifn-ω in naturally fiv-infected cats, and initial clinical scores were obtained that were similar to those obtained using the licensed subcutaneous protocol [92] . interestingly, similar to the use of the licensed protocol, rfeifn-ω also induced a significant clinical improvement of cats that were treated orally, despite viral excretion, while there were no significant variations in acute-phase proteins [92] . these results suggest that oral administration of rfeifn-ω can be an effective alternative therapy for fiv-infected cats. fcgs is a multifactorial disease. some infectious viral diseases, such as fiv, fhv-1, and felv, can also trigger fcgs by inducing immune suppression and dysregulation [93, 94] . some studies showed that oral treatment with rfeifn-ω was a beneficial therapy for fcgs. a study conducted by hennet et al. [55] found that the oral protocol correlated with an obvious clinical improvement of fcgs lesions (caudal stomatitis and alveolar/buccal mucositis). furthermore, the only difference between rfeifn-ω and corticosteroids were that better pain relief was obtained with the rfeifn-ω treatment. recently, two clinical cases showed that the use of oral rfeifn-ω was also effective in type ii diabetic cats with fcgs [95] . in this study, a clinical improvement of oral lesions and a concurrent reduction of the required insulin dose had a positive relationship with rfeifn-ω therapy, which agrees with hennet's work showing that there was an overall relief of pain in refractory cases of fcgs [55, 95] . parvovirus, a small, non-enveloped, single-stranded dna virus, infects humans and carnivores in a host-specific manner. canine parvovirus type-2 (cpv), feline panleukopenia virus, and mink enteritis virus share approximately 98% homology in their nucleotide and amino acid sequences [96] . there are several therapies used to treat cpv infections; however, many of them have drawbacks [50] . reports suggest that rifn-ω has a significant therapeutic effect on cpv-infected dogs [97, 98] . for instance, it improved parvoviral clinical signs (such as pyrexia, vomiting, anorexia, and diarrhea), and reduced severe parvoviral enteritis and mortality in cpv infections. a study by kuwabara et al. [48] showed that continuous immunoenhancement after rfeifn-ω treatment and whole blood cells counts > 5 × 10 3 /μl in dogs might be essential for improving severe clinical symptoms caused by cpv infection. cpxv, belonging to the orthopoxvirus genus, is most frequently found in domestic cats with > 400 cases having been reported, and it is endemic in northern europe and western areas of the former soviet union [99, 100] . however, until now, no antiviral drugs have been licensed to cure cats of cpxv infection. a recent study conducted by mcinerney et al. [101] showed that treatment with rfeifn-ω had a certain protective effect in cats infected with cpxv, although two of the four cats in the study died. nevertheless, rfeifn-ω may be potentially useful for treating cpxv-associated pneumonia and dermatitis in cats. of note, additional research is needed before this can be confirmed. fibrosarcoma, a common disease in cats, accounts for over 40% of all skin tumors in this species [102] . currently, few successful treatments for fibrosarcoma have been reported in cats, although treatment of feline fibrosarcoma with rfeifn-ω has been demonstrated to be safe, well tolerated, and easily performed. a study by hampel et al. [103] revealed that rfeifn-ω increased the expression of major histocompatibility i molecules on feline fibrosarcoma cells, while eosinophilia, neutropenia, and weight loss were remarkably reduced by rfeifn-ω treatment. however, a placebo-controlled trial is needed. cad is a common, allergic skin disease. some therapeutic protocols have been reported, such as allergen-specific immunotherapy, the use of topical and oral glucocorticoids and calcineurin inhibitors, essential fatty acid supplementation, and bathing [104] . however, none of them were highly efficacious, and some severe side-effects were observed occasionally. fortunately, a study showed that treating dogs with cad with subcutaneously administered rfeifn-ω had a comparable efficacy to orally-administered cyclosporin [105] . in later studies [106] , oral ifn therapy showed higher efficacy than the subcutaneous treatment in terms of the canine atopic dermatitis extent and severity index and total scores, although the improvement of pruritus and quality of life scores were not significant; however, in this study, serum antibodies against rfeifn-ω were not detected in any of the dogs. fip is a common immune-mediated disease that is triggered by infection with a feline coronavirus [107] . previous studies showed that ifn-ω is a beneficial therapy in fip-infected cats. however, these studies used fewer than 12 cats per group and did not include a control group. furthermore, the effect of ifn-ω was not reliably confirmed in fip [108, 109] . for instance, in a study of cats suspected of having fip, 12 cats were treated with 106 u/kg of feline feifn-ω every other day until remission, followed by injections every week; four of the 12 cats lived longer than 2 years [108] . in a subsequent study conducted by ritz et al. [109] , a control group was used, but there were no significant differences between the survival times of cats treated with feifn-ω and a placebo, although the feifn-ω treatment resulted in a significantly lower lymphocyte count. interestingly, one cat survived > 3 months in the feifn-ω group. these results suggest that feifn-ω could also have a certain therapeutic effect in fip-infected cats. as an ifn, ifn-ω has been demonstrated to have similar levels of biological activities as ifn-α and ifn-β, which are limited by their toxicity and side effects; thus, ifn-ω may be a useful and alternative antiviral agent. although rfeifn-ω has only been registered to treat cpv, felv, and fiv infections, it shows comparable efficacy when used to treat other viral infections or diseases. however, its safety (e.g., toxicity and side effects) when used at a high dose has not been investigated extensively. in addition, the antiviral activity of ifn-ω in some fatal infectious diseases also needs to be 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with feline infectious peritonitis the authors declare no conflicts of interest. key: cord-291559-h6czy5bh authors: koirala, prashamsa; jung, hyun ah; choi, jae sue title: recent advances in pharmacological research on ecklonia species: a review date: 2017-08-24 journal: arch pharm res doi: 10.1007/s12272-017-0948-4 sha: doc_id: 291559 cord_uid: h6czy5bh the genus ecklonia (lessoniaceae, phaeophyceae), commonly called kelp (brown algae), is abundant on the coasts of japan and korea. during the past few decades, ecklonia species have received tremendous attention for their wide range of therapeutic properties and multiple health benefits, such as great nutritional value and being rich in vitamins, minerals, dietary fiber, proteins, and polysaccharides. several novel functional ingredients with diversified biological activities have been isolated and possess antimicrobial, antiviral, hepatoprotective, cardioprotective, anti-inflammatory, neuroprotective, anticarcinogenic, immunomodulatory, hypolipidemic, anti-diabetic, and antioxidant therapeutic properties. the present review discusses the phytochemical, pharmacological, therapeutic, nutritional, and health benefits of different species of genus ecklonia, as well as their use in the prevention of disease and maintenance of good health. seaweed is used as a vegetable and traditional medicine in east-asian countries such as japan, korea, and china. it is an important resource of the marine ecosystem, containing active metabolites with probable nutraceuticals that are rich sources of novel bioactive secondary metabolites and harbor diverse classes of health-promoting molecules, including essential dietary fiber, fatty acids, essential amino acids, and vitamins a, b, c, and e (kolb et al. 2004) . taxonomic classification divides seaweed into three major classes based more on their pigments and coloration than their genetics: rhodophyceae (red algae), phaeophyceae (brown algae), and chlorophyceae (green algae, also known as macroalgae) (rajasulochana et al. 2009 ). brown algae have been used for thousands of years, but only in modern times have they been recognized to contain bioactive substances such as polysaccharides, lipids, and polyphenols, with various pharmacological properties (kumar et al. 2008) . ecklonia is a genus of kelp (brown algae) belonging to the family lessoniaceae that has an abundance of eckoltype phlorotannins. there are nine species: ecklonia biruncinata, ecklonia brevipes, ecklonia cava (ec), ecklonia fastigiata, ecklonia kurome (ek), ecklonia maxima (em), ecklonia muratii, ecklonia radiate (er), and ecklonia stolonifera (es) (hornemann 1828; moon et al. 2008) . ec, an edible marine brown alga, is used as a food ingredient, animal feed, and fertilizer, as well as a raw material in the production of fucoidan and phlorotannin. ec is also used as an herbal remedy in the form of an extract called seanol, a polyphenolic extract, and ventol, a phlorotannin-rich natural agent with two major constituents, phlorotannins and sterols (kang et al. 2003a) . es (turuarame), ek, and er are edible species traditionally eaten in japan and korea and are rich in phlorotannins and fatty acids. ecklonia species are known to exhibit antioxidant (heo et al. 2005) , anti-inflammatory , antibacterial , anti-diabetic (jung et al. 2008) , anticancer (kong et al. 2009 ), anti-photoaging (joe et al. 2006) , anti-hiv (artan et al. 2008) , anti-hypertensive (jung et al. 2006) , hepatoprotective (jung et al. 2014a) , and anti-allergic activities (le et al. 2009 ). due to these numerous health benefits, they have been a focal point for researchers eager to elucidate their pharmacological potential. plenty of information regarding the pharmacological activities of terrestrial plants is available; however, such information is limited for marine species (shibata et al. 2008) . a handful of excellent studies are available regarding the pharmacological activities of ecklonia (wijesinghe and jeon 2012; thomas and kim 2011; li et al. 2011; . also, jiao et al. (2011) have reported the chemical structures and bioactivities of marine algae. fourteen years of research and nearly $35 million of clinical studies demonstrate the importance of ecklonia species. ecklonia-derived polyphenols are unlike those found in land-based plants and are quite possibly the most powerful antioxidants found in nature, being 10-100 times more powerful than other polyphenols. the oxygen radical absorbance capacity (orac) score of such a polyphenol is more than 8300. the water-soluble polyphenols found in land-based plants have a half-life of about 30 min, and their antioxidant powers decrease very quickly (seanol 2007) . various phlorotannins, polysaccharides, enzymatic extracts, and organic extracts from ecklonia exhibit multifaceted beneficial effects when used in pharmaceuticals, nutraceuticals, cosmeceuticals, and functional foods. thus, this genus has been a target of special attention, and consumer-driven demand has led to the development of marine-derived medicines. our review summarizes the literature on the biological characterization and pharmacological bioactivity of various ecklonia species, focusing on recent developments in the therapeutic application of extracts and isolates. a shift in the balance between oxidants and antioxidants in favor of oxidants is called oxidative stress (table 1) . it arises when the balance between the production of reactive oxygen species (ros) and antioxidant defenses changes. human cells have an inherited antioxidative defense system in the form of various enzymatic and non-enzymatic pathways for removing ros. elevated production of ros increases oxidative stress, leading to cellular dysfunction, and it can eventually contribute to many pathological conditions, including neurological disorders (agostinho et al. 2010) , diabetes (ceriello 2008) , cancer (perse 2013) , asthma , and dermal disease (trouba et al. 2002 ). an ethanolic extract of ec attenuated h 2 o 2 -induced comet tail formation and phospho-histone ch2ax expression. furthermore, it enhanced the level of the phosphorylated form of nuclear factor erythroid 2-related factor 2 (nrf2) and its nuclear translocation, which was associated with the induction of heme oxygenase-1 (ho-1) and nad'ph-quinone oxidoreductase-1 (nqo-1). thus, ec provided cytoprotective effects against oxidative stress in muscle cells via up-regulation of nrf2-ho-1 and nqo-1 expression through the activation of the mitogen-activated protein kinases (mapk) pathway, which could be due to its phenolic content (choi 2016) . in another study, es and ek showed high total phenolic content (tpc) and high antioxidant activity, including 1,1-diphenyl-2-picryl-hydrazyl (dpph) radical and hydroxyl (•oh) radical scavenging, ferrous reducing power, and superoxide (•o 2 -) radical scavenging activity. those results suggest that macroalgal beach-casts could be used as a new natural source for functional foods, cosmetics, medicines, and fertilizer instead of being processed into landfills or incinerated (kuda and ikemori 2009) . enzymatic extracts from er demonstrated more potent antioxidant ability in the ferric reducing ability of plasma (frap) and orac assays (tpc of 4.4 g) than conventional acidic extracts (tpc of 3.4 g), showing their potential for value-added nutritional products (charoensiddhi et al. 2015) . inflammation is a pathological condition that produces highly reactive species. nitric oxide (no), a small diffusible molecule responsible for vasodilatation, neurotransmission, and inflammation, is produced by organisms at a basal concentration. however, under stimulation by pathogens, no is generated in higher amounts by the inducible nitric oxide synthase (inos) in activated macrophages (moncada et al. 1991) . nonsteroidal anti-inflammatory drugs are commercially available medications for inflammatory pain, but their side effects have limited their use. anti-inflammatory drugs from natural resources have been sought due to the persistent deleterious side effects of commercial medications. ec dose-dependently suppressed inos and cyclooxygenase-2 (cox-2) protein expression and subsequently reduced no content in phorbol-12 myristate 13-acetate enzymatic extracts nf-jb lee et al. (2013c) (30 nmol/l) and a23187 (1 lmol/l) (pmaci)-stimulated human mast cell line-1 cells. no production decreased by 25.4 and 46.6% with 50 and 100 lg/ml ec treatments, respectively. furthermore, ec dose-dependently inhibited both the mrna and protein expression of tumor necrosis factor (tnf)-a, interleukin (il)-1b, and il-6 in pmacistimulated human mast cell line-1 cells without any cytotoxic effects. the inhibitory effects of ec on il-1b (75.0%) and tnf-a (60.6%) production were greater than those on il-6 (23.0%) at 100 lg/ml. in addition, ec exerted anti-inflammatory action via the inhibition of the extracellular signal-regulated kinase (erk)/mapk signaling pathway, suggesting a potent and efficacious antiinflammatory agent against mast cell-mediated inflammatory diseases (kim 2014d . the world health organization (who) defines diabetes as a chronic disease that occurs when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces, which leads to an increased concentration of glucose in the blood, i.e., hyperglycemia. type 1 diabetes (previously known as insulin-dependent) is characterized by a lack of insulin production. type 2 diabetes (formerly called non-insulindependent) is caused by the body's ineffective use of insulin, often from excess body weight and physical inactivity. the total number of people with diabetes is projected to rise from 171 million in 2000 to 366 million in 2030 (rathmann and giani 2004) . intensive insulin therapy carries a high risk of side effects, especially the occurrence of severe hypoglycemia; therefore, research into antihyperglycemic agents has focused on plants used in traditional medicine because they could provide better treatment than the currently used synthetic drugs (mccall 2012) . kimchi has been a popular side dish in korea since ancient times. baechu kimchi is a salt fermented cabbage widely consumed in traditional korean foods. a recent study revealed that kimchi with added ec extract showed high inhibition against a-glucosidase and a-amylase, with ic 50 values of 0.58 and 0.35 mg/ml, respectively. both of those inhibitory activities of kimchi with added ecklonia extracts (ke) were higher than those of kimchi extract alone. the hypoglycemic effect of ke was higher than that of kimchi extract on starch loading. ke suppressed the postprandial blood glucose level in both streptozotocin (stz)-induced diabetic and normal mice, which indicated a delay in the absorption of dietary carbohydrates consumed . in another report, baechu kimchi with added ec extract protected human umbilical vein endothelial cells (huvecs) from damage induced by high glucose by restoring cell viability and reducing lipid peroxidation and intracellular ros in a dose-dependent manner. furthermore, it reduced the overexpression of inos, cox-2, and nuclear factor-jb (nf-jb) proteins in huvecs, indicating its potential as a treatment against high glucose-induced oxidative stress . ek inhibited carbohydrate-hydrolyzing enzymes, decreased postprandial blood glucose levels, and improved glucose tolerance, decreasing both fasting blood glucose and insulin levels (xu et al. 2012) . ek effectively down-regulated blood glucose in both db/db mice and prediabetic c57bl/6j mice, indicating the presence of the active compounds in the gametophytes. ek regulated metabolism by manipulating the balance among cytokines, including interferon-gamma (ifn-c) or leptin, resulting in the downregulation of blood glucose (dwiranti et al. 2012 ). the liver is involved in the metabolism of internal and external toxic agents. it has an astounding role in the performance, maintenance, and regulation of homeostasis in the body and is engaged in almost all biochemical pathways of growth, fight against diseases, nutrient supply, energy provision, and reproduction. it plays a vital role in the detoxification of xenobiotics and drugs (agrawal et al. 2013) . hepatic disease is a term that indicates damage to liver cells, tissues, structures, or function. because no drug currently available completely or effectively stimulates hepatic function, offers complete protection to the organ, or aids in regenerating hepatic cells, naturally derived hepatoprotective agents are needed to negate the factors that contribute to liver damage. a polyphenol-rich fraction of ec prepared in gijang prevented diabetes by regulating various metabolic processes, such as lipogenesis, lipolysis, inflammation, and the antioxidant defense system in livers and adipose tissues affected by nonalcoholic fatty liver disease in high fat diet (hfd)-fed mice. magnetic resonance imaging/magnetic resonance spectroscopy (mri/mrs) analysis showed that liver fat and liver volume in hfd-triggered obese mice decreased following gijang extract treatment. furthermore, the treatment reduced the mrna expression levels of inflammatory cytokines and hepatic lipogenesis-related genes and increased the mrna expression level of cholesterol 7a-hydroxylase 1, the key enzyme in bile acid synthesis. thus, gijang extract ameliorated hepatic steatosis by suppressing inflammation and improving lipid metabolism . apart from this, ec increased the activity of alcohol dehydrogenase, aldehyde dehydrogenase, and cyclic adenosine monophosphate (camp) concentration, suggesting that it plays a role in the activities of alcohol-metabolizing enzymes and their regulating mechanisms in ethanol-treated hepatocytes. ec inhibited cytochrome p450 2e1 expression related to the production of ros (yamashita et al. 2015) . a study investigated the protective effect of es in alcoholic fatty liver and found that es treatment suppressed adipogenesis and increased the expression of fatty acid oxidation-related genes, e.g., peroxisome proliferator-activated receptor (ppar)-a and cpt-1, but decreased the expression of sterol regulatory element-binding protein (srebp)-1, a triglyceride (tg) synthesis-related gene, suggesting that es extract could be useful in preventing fatty acid oxidation and reducing lipogenesis in ethanol-induced fatty liver (bang et al. 2016) . neurodegenerative diseases are expected to surpass cancer as the second most common cause of death among the elderly by the 2040s (lilienfeld and perl 1993) . alzheimer's disease (ad) is characterized by loss of memory and other cognitive functions and accounts for most of the deaths in the elderly. an increase in acetylcholinesterase (ache) level around b-amyloid plaques and neurofibrillary tangles is a common feature of ad neuropathology (lam et al. 2016 ). parkinson's disease (pd) is a multidimensional progressive disease with many motor and non-motor features, including cognitive dysfunction. adverse intra-and extracellular effects of toxic a-synuclein are believed to be central to the pathogenesis of pd and other nervous system disorders with lewy body pathology (goldman and postuma 2014; ingelsson 2016) . many categories of natural and synthetic neuroprotective agents have been reported. considering the devastating side effects of synthetic neuroprotective agents, there is growing interest in nutraceuticals or other herbal alternatives (pangestuti and kim 2011) . a study by kang et al. (2013d) demonstrated that ec n-buoh extract regulated the expression and activity of csecretase and a-secretase, leading to a reduction in ab production by the stable cells and a reduction in the basal nuclear location of the psen1 responsible for chromosome mis-segregation in neurodegenerative disease. ec and ek together inhibited ache and bace1 by 84.41 ± 1.70 and 81.17 ± 2.43%, respectively, reducing neuronal cell death and improving dementia, highlighting their synergistic potential. ek likewise showed the highest result of the 2,2 0 -azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (abts) assay (ic 50 = 0.07 ± 0.01 mg/ml), which the researchers attributed to its tpc (son et al. 2016) . kim et al. (2014e) further highlighted the importance of ec for its potential analgesic effects in postoperative pain and neuropathic pain. ec extracts (300 mg/ kg) significantly increased the mechanical withdrawal therapy value. the number of ultrasonic distress vocalizations in the treated group of rats was reduced at 6 and 24 h after plantar incision operation (62.8%). ec also increased the paw withdrawal latency in hot-and coldplate tests in the plantar incision rats. after 15 days of continuous treatment, ec (300 mg/kg) alleviated the spared nerve injury-induced hypersensitivity response, which could revolutionize the use of natural resources for therapeutic treatment. matrix metalloproteinases (mmps), known as matrixins, are a large family of similar proteolytic enzymes involved in tissue remodeling associated with various physiological and pathological processes, such as morphogenesis, angiogenesis, tissue repair, arthritis, chronic heart failure, chronic obstructive pulmonary disease, chronic inflammation, and cancer metastasis. as a result, mmps are considered viable drug targets in the therapy of those diseases (dormán et al. 2010) . according to gelatin zymography results, extracts harvested from ec and ecklonia bicyclis showed higher inhibitory effects on mmp-2 and -9 activity than those from the other marine plants at concentrations of 10, 50, and 100 lg/ml (bae et al. 2015) . the global epidemic of bacterial resistance to existing antibiotics such as b-lactams and quinolones necessitates the discovery of potent candidates from natural resources, both terrestrial and marine. the evolution of antibacterial biomolecules alongside bacteria over millions of years allow them to overcome strains such as methicillin-resistant staphylococcus aureus (mrsa) and fluoroquinoloneresistant pseudomonas (ramanan et al. 2016) . therefore, exploring and developing cheaper and more effective natural antimicrobial agents with better potential and fewer side effects than existing antibiotics, good bioavailability, and minimal toxicity is a public health priority (pérez et al. 2016) . a recent study showed that ec with ciprofloxacin evinced potent antibacterial activity against enterococcus faecalis, showing synergistic effects. etoac exhibited the strongest antibacterial activity, with a minimum inhibitory concentration (mic) value of 128 lg/ml against e. faecalis strains. furthermore, the combination of ciprofloxacin and the etoac fraction resulted in a p fic min of 0.188 and p fic max range of 0.508-563, suggesting that the ciprofloxacin-etoac combination resulted in an antibacterial synergy effect against e. faecalis (kim et al. 2015c) . ec led to the strongest growth effects on three lactic acid bacteria and fish pathogenic bacteria in a dose-dependent manner. secondary metabolites produced by ec significantly inhibited the growth of pathogen bacteria. in a further in vivo study, the co-treatment of ec and l. plantarum improved the growth and mortality of edwardsiella tardainfected zebrafish by regulating the expression of inflammatory molecules such as inos and cox-2. altogether, ec played an important role as a potential prebiotic and protected against the infection caused by e. tarda injection in zebrafish . ec (1.0%) improved the growth and body weight of olive flounder and decreased its mortality from e. tarda without changing its biochemical profile. the supplementation of 1.0% ethanolic extract of ec also enhanced the innate immune response of the fish, as evidenced by a high respiratory burst and increased serum lysozyme and myeloperoxidase activity. thus, ec acted as a prebiotic by improving the innate immune response in fish infected with pathogenic bacteria (lee et al. 2016c ). seanol, a seaweed extract rich in phlorotannins, stimulated mineralization with calcium phosphate, increased antibacterial activity, and increased compressive modulus. seanol and alkaline phosphatase (alp) interacted in a non-covalent manner. seanol exhibited antibacterial activity against mrsa with comparable cytotoxicity toward mg-63 osteoblast-like cells, suggesting its mineralizability and antibacterial activity (douglas et al. 2016) . venkatesan et al. (2014) reported the rapid biological synthesis of gold nanoparticles (au nps) using ec by reducing chloroauric acid. fourier transform infrared (ftir) spectroscopic analysis showed that au nps functionalized with biomolecules (a primary amine group, a hydroxyl group, and other stabilizing functional groups) showed good antimicrobial activity and biocompatibility with a human keratinocyte cell line. the results indicate that aunps might have promising applications in drug delivery, tissue engineering, and biosensor development. er extract prepared by using celluclast-assisted extraction induced significantly higher production of butyrate (9.2 lmol/ml) and promoted the growth of beneficial bacteria such as bifidobacterium and lactobacillus, improving gut health (charoensiddhi et al. 2016 ). ec and ek had the strongest inhibitory effects when tested using the agar disk diffusion method, with an mic of 0.31 mg/ ml and no cytotoxicity even at 200 lg/ml, indicating their potential as therapeutic agents for acne vulgaris ). obesity is a leading preventable cause of death worldwide, with increasing rates in both developed and developing countries. as defined by who, it is a medical condition in which excess body fat has accumulated to the extent that it can have negative effects on health, and it is often comorbid with diseases such as type 2 diabetes, hypertension, coronary disease, and cancer. in 1997, who announced that obesity had reached epidemic proportions worldwide (kumar and rao 2013; caballero 2007) . commercial drugs, such as orlistat; lorcaserin; and a combination of phentermine, topiramate, and bariatric surgery, such as roux-en-y bypass or gastric banding, are available. however, concerns about perioperative mortality, surgical complications, and the frequent need for reoperation mean that those procedures tend to be reserved for morbid obesity (rodgers et al. 2012 ). thus, remedies from natural sources are vital, especially those from marine sources. the anti-adipogenic activity of ec was determined by measuring lipid accumulation in adipocytes. the n-buoh fraction particularly reduced lipid accumulation and glucose consumption; the adipogenic transcription factors pparc and srebp-1c; and the adipogenic specific genes fatty acid binding protein (fabp)-4, fabp-1, fatty acid synthase (fas), lipoprotein lipase (lpl), hormone-sensitive lipase (hsl), and acyl-coa synthetase 1 (acs1) . ec polyphenol extract regulated fat metabolism, inflammation, and the antioxidant defense system in hfd-induced obese mice. ec polyphenol extract supplementation reduced body weight gain, adipose tissue mass, plasma lipid profiles, hepatic fat deposition, insulin resistance, and the plasma leptin/adiponectin ratio derived from hfd-induced obesity. furthermore, ec polyphenol extract supplementation selectively ameliorated the hepatic protein levels associated with lipogenesis, inflammation, and the antioxidant defense system, as well as activation of ampk and sirtuin (sirt1) to inhibit obesity (eo et al. 2015) . there has been a worldwide increase in allergic diseases, including atopic dermatitis, asthma, allergic rhinitis, and food allergies, possibly because environmental factors are interacting with genetic factors to sensitize individuals (tanaka 2014) . numerous studies have been done in the search for anti-allergens, especially from marine resources. ec extract exhibited excellent inhibitory activity against crude histidine decarboxylase (hdc), reducing overall histamine production by 46.29% and thereby enhancing the safety of mackerel muscle (kim et al. 2014g) . another report presented a 32% inhibition of hdc at a concentration of 1 mg/ml, reducing histamine poisoning by decreasing histamine production in mackerel (jung et al. 2013b) . ec and ek together inhibited the degranulation of a rat basophilic leukemia cell line (rbl-2h3), mitigating allergic symptoms and highlighting their synergistic potential (yoshioka et al. 2013) . phlorotannin-rich es inhibited enzymatic activity and degranulation in stimulated rbl-2h3 cells in a dose-dependent manner. the meoh: chloroform (1:2, v/v) (m/c) extract of es also inhibited enzyme activity and degranulation in stimulated rbl cells in a dose-dependent manner. the active compounds in the m/c extract might be phenolic compounds, such as phlorotannins, because the m/c extract became inactive when the phenolic compounds were removed (sugiura et al. 2012) . ionizing radiation produces deleterious effects, deterministic or stochastic, on living organisms, though it can have health benefits in the form of radiation therapy for the treatment of cancer or thyrotoxicosis. the benefits of ionizing radiation are compromised by the side effects that result from radiation-induced damage to normal tissue, and the synthetic agents used to combat those side effects, wr2721 (amifostine), ok-432, and ethiofos, have their own serious side effects, including decreased cellular function, nausea, hypotension, and death (baliga and rao 2010; park et al. 2008) . therefore, investigators have directed their attention toward plants and other natural products. enzymatic extracts of ec exhibited radioprotective properties, including the modulation of apoptosis via inhibition of the nf-jb signaling pathway ). ecklonia species and their constituents exhibit pronounced inhibitory effects against oxidative stress (table 2) . ec phlorotannins, including phloroglucinol (pg), eckol, dieckol, eckstolonol, and triphlorethol-a (tpa), scavenged intracellular ros, inhibited lipid peroxidation, and suppressed 2,2 0 -azobis(2-amidinopropane) dihydrochloride (aaph)-induced cell death in zebrafish embryos. these phlorotannins maintained the positive changes in morphological phenomena; pericardial edema, yolk sac edema, and growth retardation in zebrafish embryos exposed to aaph were not observed in the groups also exposed to phlorotannins, indicating that the phlorotannins possess prominent antioxidant activity against aaph-mediated toxicity (kang et al. 2013a) . tpa further exhibited a protective effect against oxidative stress-induced dna-base damage, especially 8-oxoguanine (8-oxog), in v79-4 cells. decreased level of 8-oxog induced by h 2 o 2 were confirmed by an increase in ogg1 mrna and ogg1 protein levels. tpa restored the expression of nuclear nrf2, small maf protein, and the nrf2-maf complex and also increased nrf2 binding to are sequences and the resulting ogg1 promoter activity. sequentially, it maintained the levels of the phosphorylated forms of akt kinase downstream of phosphatidylinositol 3-kinase (pi3k) and erk, which are regulators of ogg1, suggesting that ogg1 induction by tpa involves the pi3k/akt and erk pathways . eckol from ec also attenuated the high intracellular ca 2? levels stimulated by h 2 o 2 , decreased the augmented levels of mitochondrial ros, recovered h 2 o 2 -diminished atp level and succinate dehydrogenase activity, and induced manganese superoxide dismutase through phosphorylated ampk and forkhead box o3a (foxo3a), which showed a cytoprotective effect on chang liver cells ). fucoidan extracted from ec exhibited prominent effects on peroxyl radical scavenging activity and 2, 2 0 -azobisdihydrochloride-induced oxidative stress in vero cells and reduced ros generation, lipid peroxidation, and cell death in a zebrafish model, proving its antioxidant capacities in vitro and in vivo despite being neither a polyphenol nor a flavonoid. although, it did not contain a benzene ring or conjugated structure, it exhibited antioxidant potential (kim et al. 2014c ). in another study, 6,6bieckol, 7-phloroeckol, dieckol, and phlorofucofuroeckol (pff-a) isolated from ec significantly inhibited high glucose-induced ros and cell death in zebrafish. dieckol significantly reduced heart rate, ros, no, lipid peroxidation generation, and cell death and also reduced the overexpression of inos and cox-2, thereby preventing oxidative stress . es could be used as a natural antioxidant and cytoprotective agent. es inhibited ros even at a concentration of 25 lg/ml, yielding five compounds (pff-a, dieckol, eckstolonol, pg, and eckol) that inhibited total ros, proving its use as a potent scavenger (kang et al. 2004) . three active compounds were isolated from es, pff-a, dieckol, and dioxinodehydroeckol (dhe), among which pff-a and dieckol significantly suppressed intracellular ros in lipopolysaccharide (lps)induced raw264.7 cells, and dhe scavenged dpph radicals. pff-a also significantly inhibited the lps-induced production of no and prostaglandin e2 (pge2) through the down-regulation of inos and cox-2 protein expression ). dieckol and pff-a obtained from boiling water-and organic solvent extracts of ec and es showed almost 9-and 7-fold stronger antioxidant activity than the standard butylhydroxytoluene, and 6-and 4-fold greater activity than l-ascorbic acid in molar concentration, anti-inflammatory activity ecklonia cava dieckol decreased blood glucose level kang et al. (2013b) insulin resistance lee and jeon (2015) akt up-regulation kim et al. (2016b) phlorofucofuroeckol-a a-glucosidase and a-amylase fucodiphlorethol g uvb induced oxidative stress kim et al. (2014f) respectively (chowdhury et al. 2014) . three known phlorotannins, eckol, pff-a, and dieckol, along with one new compound, eckstolonol, were obtained from es, and the new compound was found to be a potent radical scavenger through its elimination of dpph radicals (kang et al. 2003b) . eckol suppressed the production of intracellular ros and increased glutathione peroxidase (gsh) level in hepg2 cells. it inhibited the production of ros in h 2 o 2treated hepg2 cells in a dose-dependent manner, and the total relative level of 40 lm eckol was estimated to be 11.2 ± 0.85% compared to the non-treated group, making it a much stronger ros scavenger than n-acetylcysteine (nac). the intracellular gsh content in hepg2 cells was dose-dependently enhanced by eckol treatment, indicating higher antioxidant activity than nac. thus, eckol mediated the expression of ho-1 in hepg2 cells, which was regulated by nrf2 activation via the jun n-terminal kinases (jnk) and pi3k/protein kinase b (akt) signaling pathways, suggesting that it is a natural antioxidant and cytoprotective agent (jun et al. 2014 (fig 1) . ec extract and its major compound (dieckol) significantly increased the survival rate and attenuated liver and kidney damage in mice with a whole-body inflammatory condition by down-regulating pro-inflammatory factors (inos, cox-2, tnf-a, il-6, and hmgb-1) via a nik/tak1/ ikk/ijb/nf-jb pathway. additionally, ec increased nrf2 and ho-1 expression, reducing inflammation (yang et al. 2016) . dieckol (5 and 10 lm) inhibited the production of a macrophage-derived chemokine, c-c motif chemokine 22, induced by interferon-c (10 ng/ml) in a dose-dependent manner and inhibited the nuclear translocation of signal transducers and activators of transcription 1 (stat1). these results showed that dieckol produced anti-inflammatory effects via the down-regulation of stat1 activation . in addition, 8,8 0 -bieckol isolated from ec suppressed key inflammatory mediators such as no and pge2 in raw264.7 macrophages. the inhibition of no occurred by suppressing lps-induced expression of inos at the mrna and protein levels in primary macrophages and raw264.7 cells. likewise, 8,8 0 -bieckol reduced the production and mrna expression of the inflammatory cytokine il-6, but not that of tnf-a, in raw264.7 cells. furthermore, 8,8 0 -bieckol significantly reduced mortality in lps-induced septic mice, which indicates that the anti-inflammatory properties of 8,8 0bieckol are associated with the suppression of no, pge2, and il-6 via negative regulation of the nf-jb pathway and ros production in lps-stimulated raw264.7 cells ). dieckol extracted from ec suppressed lpsinduced inos expression in mouse leukemic macrophage raw 264.7 cells, decreasing both lps-induced no production and inos promoter-driven transcriptional activity in a dose-dependent manner. furthermore, it prevented lps-mediated nf-jb activity. it also diminished lpsmediated p65 nuclear translocation or ijba phosphorylation dose-dependently and reduced lps-induced phosphorylation of mapks, especially p38mapk. collectively, these findings suggest that dieckol acts as a negative regulator of lps-mediated inos induction by suppressing nf-jb activity, implying a mechanistic role for dieckol in the regulation of the inflammatory response . the in vivo anti-inflammatory effect of fucoidan from ec was studied using tail-cutting-induced recent advances in pharmacological research on ecklonia species: a review 991 and lps-stimulated zebrafish models; it inhibited tail-cutting-induced and lps-stimulated ros and no generation and also showed a protective effect against the toxicity induced by lps exposure in zebrafish embryos ). pff-a isolated from es showed potential antiinflammatory properties in macrophages stimulated by lps. for this, 20 lm of pff-a significantly inhibited inos and cox-2 mrna levels induced by lps stimulation. similarly, levels of pro-inflammatory cytokines such as il-1b, il-6, and tnf-a were significantly reduced. pff-a further inhibited the promoter activities of inflammatory mediators and transcriptional factors. thus, pff-a regulated inos and cox-2 expression through the nf-jbdependent transcriptional control associated with the inhibition of multiple signaling proteins, suggesting that pg derivatives could be potential treatments for inflammatory diseases . the etoac fraction of es, along with its isolated compounds 2-phloroeckol, 6,6 0bieckol, pff-a, pff-b, and 974-b, inhibited the production of lps-induced no and pge2 and reduced the expression of inos and cox-2 in a dose-dependent manner (wei et al. 2016 ). most of the investigations on phlorotannins, particularly those derived from brown algae, indicate their promising anti-diabetic effects. for example, 2,7 00 -pg-6,6 0 -bieckol isolated from ec improved postprandial hyperglycemia through a-glucosidase and a-amylase activity in stz-induced diabetic mice. it showed higher inhibitory activity than the positive control, acarbose (a-glucosidase ic 50 of 130.04 lm; a-amylase ic 50 of 165.12 lm) (lee et al. 2017a ). in addition, 6,6 0 -bieckol purified from ec at concentrations of 10 or 50 lg/ml significantly inhibited high glucose-induced glucotoxicity and dose-dependently reduced the level of thiobarbituric acid reactive substances (tbars), generation of intracellular ros, and the level of no. furthermore, 6,6 0 -bieckol prevented the apoptosis of rat insulinoma cells under high-glucose conditions, attributed to increased expression of the anti-apoptotic protein bcl-2 and reduced expression of the pro-apoptotic protein bax, establishing ec as a potential nutraceutical candidate for protection against glucotoxicity (park et al. 2015a ). 6,6 0 -bieckol from ec at concentrations of 10 or 50 lg/ml markedly suppressed high-glucose-induced cytotoxicity and dose-dependently decreased the increased levels of tbars, ros, and no caused by high glucose. in addition, it down-regulated the overexpression of inos, cox-2, and nf-jb proteins in huvecs, indicating its therapeutic ability to treat diabetic endothelial dysfunction and related complications ). ec-derived dieckol noticeably decreased blood glucose level, serum insulin level, and body weight. furthermore, it reduced tbars and increased the activities of antioxidant enzymes, including superoxide dismutase (sod), catalase (cat), and gsh-px, in liver tissue. in addition, western blotting analysis revealed that dieckol increased the phosphorylation levels of ampk and akt observed in muscle tissues, suggesting that dieckol could be a therapeutic agent for type 2 diabetes ). dieckol-rich extract from ec led to a significant decrease in postprandial glucose level, insulin, and c-peptide level after 12 weeks without any adverse effects. in other words, ec supplementation significantly contributed to lowering postprandial hyperglycemia and reducing insulin resistance . in addition, dieckol improved blood glucose regulation, hepatic glucose metabolic regulation, and akt up-regulation in alloxan-induced hyperglycemic zebrafish ). pff-a isolated from ec showed prominent inhibitory effects against a-glucosidase and a-amylase activities, with ic 50 values of 19.52 and 6.34 lm, respectively, which were higher than those of acarbose. moreover, the area under the curve was significantly lower after pff-a administration (2296 vs. 2690 mmol min/l) in diabetic mice, indicating its potent anti-diabetic activity (you et al. 2015) . the a-glucosidase inhibitory property of em and its isolated compounds pg, dibenzo [1,4] dioxine-2,4,7,9-tetraol, and eckol exceeded that of the positive control, suggesting their potency as oral anti-diabetic drugs or functional food ingredients, with a promising role in the formulation of medicines and nutritional supplements (rengasamy et al. 2013) . es exhibited inhibitory activity on glucose-mediated protein damage, advanced glycation end-products (age), and rat lens aldose reductase (rlar), hinting at potential antidiabetic activity. in spite of negligible activity against age, es phlorotannins, including eckol, dieckol, and 7-phloroeckol, possessed inhibitory activity on glycation, which indicates that pff-a could be used to prevent diabetic complications (jung et al. 2008) . likewise, fucosterol from es inhibited rlar, human recombinant aldose reductase, protein tyrosine phosphatase 1b (ptp1b), and a-glucosidase activity (jung et al. 2013a ). pff-a, dieckol, and 7-phloroeckol isolated from es were potent and non-competitive ptp1b inhibitors, with ic 50 values ranging from 0.56 to 2.64 lm, and a-glucosidase inhibitors, with ic 50 values ranging from 1.37 to 6.13 lm. interestingly, pff-a and 7-phloroeckol were non-competitive, whereas dieckol exhibited competitive inhibition in a a-glucosidase assay. thus, isolated phlorotannins from both algae possessed marked ptp1b and a-glucosidase inhibitory activity that could contribute to the development of therapeutic agents to control postprandial blood glucose level and prevent diabetic complications (moon et al. 2011) . published results clearly indicate the anti-diabetic potential of brown seaweed and its derived components, which could be used as nutraceuticals or functional foods to treat diabetes. pyrogallol-phloroglucinol-6,6'-bieckol fucoidan dieckol from ec exerted cytotoxicity in lx-2, hsc-t6, and hepg2 cells, with reduced fibrosis features (large, spread out, and flattened polygonal shapes) in lx-2 cells compared with the untreated control. in addition, it attenuated the expression of a-sma and tgf-b1, increased the sub-g1 phase population, induced caspase-3 activation, and cleaved parp in hepatic stellate cells. thus, dieckol suppressed liver fibrosis via caspase activation, micro-rna-mediated jnk activation, and via nf-jb inhibition ). an in vitro study of dieckol showed the strongest protective effect and lowest cytotoxicity against ethanol-induced cell apoptosis in chang liver cells. western blot analysis revealed reduced cell apoptosis through the activation of b cell lymphoma-extra large (bcl-xl) and parp and down-regulation of bax and caspase-3, providing evidence for this potential protective agent against ethanol-induced liver diseases. in an in vivo study in a zebrafish model, the dieckol-treated group scavenged intracellular ros and prevented lipid peroxidation and ethanol-induced cell death in embryos (kang et al. 2013c cytochrome c from mitochondria to the cytosol in a dosedependent manner (lee et al. 2012a ). pg isolated from es decreased the formation of lipid peroxide in acetaminophen (800 mg/kg, i.p.)-induced rats. though the activities of cytochrome p-450, aminopyrine n-demethylase, and aniline hydroxylase were unchanged, pg restored enzyme activity in the livers of pretreated-rats, suggesting that acetaminophen-induced hepatic lipid peroxidation could be reduced by enhancing the activity of glutathione s-transferase (gst) (park 2000) . all of these data suggest that ecklonia species could be potent hepatoprotective agents. dieckol isolated from ec suppressed the phosphorylation of erk in lps-stimulated bv-2 microglia (1 lg/ml), attenuated akt phosphorylation, and increased the expression of gp91 phox , a catalytic component of the nicotinamide adenine dinucleotide phosphate (nadph) oxidase complex responsible for microglial ros generation. furthermore, dieckol offered neuroprotection, as confirmed in an enhanced green fluorescent protein-transfected b35 neuroblastoma cell line (cui et al. 2015) . dieckol isolated from ec showed potent activity on rotenone-induced oxidative stress in sh-sy5y cells, a human dopaminergic neuronal cell line. it reduced rotenone-induced cell death and retarded rotenone-induced a-synuclein aggregation in asynuclein-overexpressing sh-sy5y cells, which prevented a-synuclein aggregation, adding to its role in the prevention of pd (cha et al. 2016) . pg (1,3,5-trihydroxybenzene) from ec attenuated the increase in ros accumulation induced by oligomeric ab1-42 treatment in the ht-22 hippocampal cell line and ameliorated the reduction in dendritic spine density induced by ab1-42 treatment in rat primary hippocampal neuron cultures. also, pg attenuated cognitive dysfunction in the hippocampal region, indicating its anti-ad effects (yang et al. 2015b) . another report showed that pff-a from ec had particularly potent inhibitory activity (ic 50 = 0.95 lm) for butyrylcholinesterase (bche), more than 100-fold greater than for ache. other polyphenols (pff-a, eckol, 6,6 0 -bieckol, 8,8 0 -bieckol, and dieckol) inhibited glycogen synthase kinase 3b, which is related to the formation of hyperphosphorylated tau and generation of ab. additionally, pff-a inhibited amyloid precursor protein biosynthesis and showed very strong bace1 inhibitory activity, with a submicromolar ic 50 , making it an interesting potential drug candidate for ad ). an oligosaccharide sugar chain derived from ek inhibited the toxicity induced by the ab protein in both primary cortical cells and the sh-sy5y cell line, inhibiting apoptosis and fibril formation and indicating its potency for ad (hu et al. 2004) . em exhibited potent activity against ache, as did its isolated compounds pg, dibenzo [1, 4] dioxine-2,4,7,9-tetraol, and eckol, highlighting its potential as a functional food ingredient for the management of neurodegenerative disorders (kannan et al. 2013) . a phlorotannin preparation (pp) containing eckstolonol from es and ec exhibited a hypnotic effect by modulating the benzodiazepine site of the c-amino butyric acid receptor. pp ([250 mg/kg) decreased sleep latency and increased non-rapid eye movement sleep (nrems). likewise, eckstolonol significantly decreased sleep latency ([12.5 mg/ kg) and increased the amount of nrems (50 mg/kg). in addition, the hypnotic effects were completely abolished by pretreatment with flumazenil, suggesting that the phlorotannins could potentially be used as an herbal medicine for insomnia and offering a promising structure for the development of novel sedative-hypnotics . fucosterol and fucoxanthin from es showed noncompetitive and mixed-type inhibition against b-site amyloid precursor protein cleaving enzyme 1 (bace1). furthermore, molecular docking simulation results demonstrated the effective binding of isolated compounds by the bace1 enzyme, suggesting that both compounds could be used beneficially in the treatment of ad and providing potential guidelines for the design of new bace1 inhibitors . isolated eckol and dieckol attenuated tnf-a induced expression of mmp-1 and basal expression, though the expression of timp-1 was not affected. however, they did reduce both nf-jb and ap-1 reporter gene activity, which strongly indicates their mmp inhibitory potential. one study demonstrated the inhibitory effect of eckol and dieckol isolated from es on mmp-1 expression in human dermal fibroblasts, suggesting the possibility of developing an agent to prevent and treat skin aging (joe et al. 2006) . obviously, marine sources outweigh terrestrial sources in abundance in the development of safe mmp nutraceuticals. anticoagulation occurs by inhibiting the key serine proteases thrombin and factor xa, facilitated by accelerating the activity of the major physiological serine protease inhibitor serpin-antithrombin iii. heparin, a highly sulfated polysaccharide present in mammalian tissues, is commercially used as a blood anticoagulant. it has antihemostasis, fibrinolytic potentiation, and anti-lipemic activity in addition to coagulation activity. though it is a primary anticoagulant, difficulty in isolating it and its hemorrhagic side effects limit its use and drive researchers to search for novel anticoagulants from natural resources free from cytotoxicity (shanmugam and mody 2000) . studies of the anticoagulant bioactivity of brown seaweeds suggest that they have more than one mechanism of action, including the direct and indirect inhibition of thrombin through the activation of thrombin inhibitors (e.g., antithrombin and heparin cofactor). interestingly, the algal fucans were found to have anticoagulant activity through a direct inhibition of thrombin, whereas the invertebrate fucans showed activity through an indirect inhibition of the enzyme, which required antithrombin and heparin cofactor ii, and that has driven the rapid discovery of anticoagulants from marine resources (jiao et al. 2011) . fucoidan isolated from ek significantly inhibited the generation of thrombin and factor xa in the intrinsic pathway. furthermore, it inhibited the formation of prothrombin-activating complex (i.e., prothrombinase); the ic 50 of thrombin generation was one-tenth to one-seventh that of the activity of the thrombin in plasma, whereas the antithrombin activity of fucoidan was mediated by heparin cofactor ii in plasma. this further highlights the relationship between the molecular weight of sulfated polysaccharides and their anticoagulant activity such that the higher molecular weight fucans show greater anticoagulant activity than sulfates with a lower molecular weight (nishino et al. 1999 (nishino et al. , 1991a . sulfated polysaccharides, mainly 3-linked and 3, 4-disubstituted fucopyranosyl residues isolated from ek, exhibited potent anticoagulant activity (nishino et al. 1991b) . some potent and novel antiplasmin inhibitors such as pff-a and eckol isolated from ek inhibited the action of alpha 2-macroglobulin (ic 50 = 1.0 lg/ml) and alpha 2-plasmin inhibitor (ic 50 = 0.3 lg/ml), the main plasmin inhibitors in plasma (fukuyama et al. 1990 (fukuyama et al. , 1989 . thus, the development of antithrombotic algal polysaccharides would be advantageous because their use would avoid the potential for contamination with prions or viruses present in commercial heparins, which are obtained from pig and bovine intestines. moreover, with more specific activities or targets, algal sulfated polysaccharides could find applications complementary to heparin. dieckol from ec significantly blocked the cleavage of sars-cov 3cl(pro) in a cell-based assay without showing any toxic effects and exhibited a high association rate in the spr sensorgram, forming strong hydrogen bonds to the catalytic dyad (cys145 and his41) of the sars-cov 3cl(pro) ). both phlorotannins from ec and isolated epibiotic bacteria showed potent antibacterial activity in close affiliation with the genus bacillus (kanagasabhapathy et al. 2006) . another novel bacterial strain, designated ec29t, was isolated from ec, and it showed potent antibacterial activity (kim et al. 2015d) . another study suggested that the compounds eckol, dieckol, pff, and 7-phloroeckol exhibited potent antiviral activity, with ic 50 ranging from 10.8 ± 1.4 to 22.5 ± 2.2 lm against porcine epidemic diarrhea. these compounds completely blocked the binding of viral spike protein to sialic acids at concentrations less than 36.6 lm by hemagglutination inhibition. pff and dieckol inhibited viral replication with ic 50 values of 12.2 ± 2.8 and 14.6 ± 1.3 lm, respectively, in the post-treatment assay and exhibited stronger inhibition of viral rna and viral protein synthesis in later stages (18 and 24 h) than in early stages (6 and 12 h), suggesting their potential as natural therapeutic drugs against coronavirus infection ). dieckol and 8,8 0 -bieckol (hexamers) isolated from ek were tested against the food-borne pathogenic bacteria campylobacter jejuni with an mic of 50 mg/l and 0.03 lmol/ml, respectively, which were effective against mrsa as determined by a broth microdilution method. the bactericidal effects of the phlorotannins were more pronounced than those of the catechins . one study showed that n-buoh fractions with isolated phlorotannins (tpa, eckol, and dieckol) increased glycerol secretion and reduced the regulation of adipogenic transcription factors, pparc, ccaat/enhancer-binding protein (c/ebpa), and tnfa. those phlorotannins also reduced the differentiation-dependent factor 1/srebp-1c and downstream genes such as fabp-4, fatty acid transport protein-1, fas, leptin, and acs1, whereas they increased the mrna expression of hormone-sensitive lipase while suppressing perilipin expression to treat obesity . dieckol from ec down-regulated the expression of pparc, c/ebpa, srebp-1, and fabp-4, showing anti-adipogenic effects on adipocyte differentiation through the activation and modulation of the ampk signaling pathway to improve obesity . enzyme-treated ec and its isolated compounds (eckol, dieckol and pff-a) exhibited potent adipogenic activity in 3t3-l1 adipocytes. dieckol was found to be the major compound in the enzymatic extract, with a concentration of 16 mg/g. in addition, 50 lg/ml of ec extract inhibited glucose utilization and tg accumulation, as confirmed by oil red o staining. additionally, it decreased the expression of ccaat/(c/ebp)a, srebp-1c, adipocyte-fabp, fas, and adiponectin. thus, ec prevented adipogenesis by affecting the activation of the c/ebpa signaling pathway and the resulting adipogenesis-related gene expression (kim and nam 2017) . in a similar report, dieckol from ec inhibited lipid accumulation via activation of ampka signaling and cell-cycle arrest in 3t3-l1 cells and mouse and zebrafish models . seapolynol derived from ec inhibited triglyceride synthetic enzymes such as diacylglycerol acyltransferase 1, gpat3, kruppellike factor 4 (klf4), klf5, c/ebpb, c/ebpd, and protein c-ets-2, whereas it up-regulated klf2, an anti-early adipogenic factor, preventing metabolic disorders . fucosterol was isolated from the strong anti-adipogenic ch 2 cl 2 -soluble fraction from es, with significant inhibition (40.5%) of intracellular lipid accumulation at a non-toxic concentration. the anti-adipogenic activities of es, along with the isolated fucosterol, reduced lipid content in a concentration-dependent manner without showing any cytotoxicity. fucosterol treatment also yielded a decrease in the expression of the adipocyte markers pparc and c/ebpa in a concentration-dependent manner. taken together, these results suggest that fucosterol inhibits the expression of pparc and c/ebpa, resulting in a decrease in lipid accumulation in 3t3-l1 pre-adipocytes, thereby indicating the potential of es and its bioactive component fucosterol as anti-obesity agents (jung et al. 2014b ). similarly, fucosterol isolated from es down-regulated the insulin-triggered pi3k/akt and erk pathways, which subsequently decreased the expression of adipogenic transcription factors, including pparc, c/ebpa, and srebp-1. in addition, fucosterol enhanced sirt1 expression and decreased phospho-foxo1 expression, which resulted in the activation of foxo1 and revealed that fucosterol inhibited adipogenesis of 3t3-l1 preadipocytes at concentrations of 25 and 50 lm through the modulation of the foxo1 signaling pathway (lee et al. 2017b) . compound 974-b isolated from ek inhibited the differentiation of mouse embryonic fibroblasts and 3t3-l1 cells into adipose cells by acting as the peptidyl prolyl cis/trans isomerase inhibitor responsible for the uptake of tg and the differentiation of fibroblasts into adipose cells in response to insulin stimulation without inducing cytotoxicity. this finding suggests that 974-b could be a lead drug candidate for obesity-related disorders (mori et al. 2014) . altogether, these results suggest that several ecklonia species possess potent activity that might be exploited in adjunct therapy for obesity. dieckol from ec inhibited mast cell activation and mast cell-mediated type i allergic reactions caused by igespecific antigen, mainly through the marked downstream signaling of fceri. a high dose of dieckol suppressed hypersensitive reactions, offering another target molecule for the prevention or treatment of mast cell-dependent allergic diseases (ahn et al. 2015c) . six phlorotannins isolated from ek, pg, an unknown tetramer, eckol, pff-a, dieckol, and 8,8 0 bieckol, inhibited hyaluronidase at concentrations of 280, 650, [800, 140, 120, and 40 lm, respectively. also, 8, , the strongest hyaluronidase inhibitor, acted as a competitive inhibitor with an inhibition constant (ki) of 3.5 lm . park et al. (2011) described the multi-faceted protection mechanisms of pg against oxidative stress caused by ionizing radiation in mice. pg inhibited apoptosis and strengthened hematopoiesis. it increased the viability of splenocytes without cytotoxicity and significantly enhanced the proliferation of splenocytes by limiting the increment of sub-g(1) dna contents via the inhibition of ros production in 2 gy-irradiated splenocytes. in addition, pg significantly decreased dna damage and the number of apoptotic fragments in lymphocytes during oxidative stress and increased the counts of endogenous spleen colony forming units (cfus) compared with control mice exposed to ionizing radiation. a similar study confirmed that pg protected against small intestine damage caused by ionizing radiation, raising the apoptosis threshold of jejunal crypt cells. pg regenerated the intestinal crypts and down-regulated the expression level of proapoptotic molecules such as p53, bax, and bak in the small intestine. pg further augmented antiapoptotic molecules such as bcl-2 and bcl-x(s/l) (ha et al. 2013) . cancer is the uncontrolled growth of cells that can invade and spread to distant sites of the body. cancer can have severe health consequences and is a leading cause of death. lung, prostate, colorectal, stomach, and liver cancer are the most common types of cancer in men, whereas breast, colorectal, lung, uterine cervix, and stomach cancer are the most common types among women. more than 30% of cancer deaths could be prevented by modifying or avoiding key risk factors. cancer results from a mutation in the chromosomal dna of a normal cell, which can be triggered by both external factors (tobacco, alcohol, chemicals, infectious agents, and radiation) and internal factors (hormones, immune conditions, inherited mutations, and mutations occurring in metabolism) (croce 2008; ferlay et al. 2015) . in korea, cancer accounts for one in four deaths (27.6%), and more than 200,000 new cancer cases were diagnosed in 2012 . although antineoplastic drugs and chemotherapy are available, the deleterious effects of those medications have driven researchers to derive new drug candidates from natural products. dieckol isolated from ec prevented n-nitrosodiethylamine (ndea)-induced rat hepatocarcinogenesis. dieckol administered orally (40 mg/kg body weight) for 15 weeks with 0.01% ndea through the drinking water reversed the activities of hepatic marker enzymes such as aspartate transaminase, alanine transaminase, alp, gamma glutamyl transferase, lactate dehydrogenase, a-fetoprotein, and total bilirubin and increased the elevation of cytochrome p450. dieckol also decreased lipid peroxidative markers (tbars, lipid hydroperoxides, protein carbonyl content, and conjugated dienes) and decreased the antioxidant cascade viz enzymatic antioxidants (such as sod, cat, glutathione peroxidase, gst, glutathione reductase) and non-enzymatic antioxidants (such as reduced glutathione, vitamin c, and vitamin e). dieckol was more effective at 40 mg/kg than at 10 and 20 mg/kg body weight and protected the liver from cancer (sadeeshkumar et al. 2016) . likewise, dieckol showed anti-breast cancer activity by regulating the expression of metastasis-related genes ). ec and its major phlorotannin (dieckol) increased the tumor growth-inhibitory effect of cisplatin and reduced cisplatin-induced nephrotoxicity and weight loss in skov3-bearing mice. furthermore, they enhanced cisplatin-induced apoptosis by stimulating caspases in skov3 and a2780 ovarian cancer cells via down-regulation of akt and nf-jb signaling. thus, ec suppressed cisplatin-induced ros production and cell death in normal hek293 kidney cells, and its major compound dieckol evidently enhanced the suppression of tumor growth by cisplatin with less weight loss and kidney damage in a mouse model . dieckol from ec exhibited cytotoxic effects on a2780 and skov3 ovarian cancer cells, induced the apoptosis of skov3 cells, and suppressed tumor growth without any significant adverse effect in the skov3-bearing mouse model. furthermore, it activated caspase-8,-9, and -3; caused mitochondrial dysfunction; and suppressed the levels of anti-apoptotic proteins. thus, dieckol enhanced intracellular ros, and the antioxidant n-acetyl-l-cysteine (nac) noticeably reversed the caspase activation, cytochrome c release, bcl-2 downregulation, and apoptosis caused by dieckol through akt and p38 ). in another investigation, ahn et al. (2015b) showed the anticancer effects of crude polysaccharides isolated from ec enzymatic extracts, using amyloglucosidase (amg), viscozyme, protamex, and alcalase enzymes against a colon cancer cell line. among the tested extracts, crude polysaccharides of protamex showed the highest inhibitory effect against the growth of ct-26 cells and dose-dependently increased the formation of apoptotic bodies and the percentage of sub-g1 dna content. furthermore, crude polysaccharides of protamex activated caspase 9 and parp to regulate the expression of bax and bcl-2 and showed the highest inhibitory effect against the growth of ct-26 cells, attributed to their high fucose and sulfated group content, demonstrating anticancer effects on colon cancer cells via regulation of the bcl-2/bax signal pathway. additionally, dieckol isolated from es reduced the number of viable cells and increased the number of apoptotic cells, increased the expression levels of cleaved caspases-(3, 7, 8, and 9) and cleaved poly(adp-ribose) polymerase, increased the permeability of mitochondrial membranes, and increased the release of cytochrome c from mitochondria into the cytosol with an apoptosis-inducing factor. thus, dieckol induced apoptosis via the activation of both death receptors and mitochondrial-dependent pathways in human hepatocellular carcinoma (hep3b) cells (yoon et al. 2013 ). the skin is the human body's largest organ and is colonized by diverse microorganisms, most of which are harmless or even beneficial to their host. it acts as an anatomical barrier that is tough when intact and prevents the entry and colonization of many microbes (grice and segre 2011) . however, continuous exposure to ultraviolet (uv) light leads to various complications correlated with various pathological consequences, such as photo-damage of the skin, which is characterized by distinct alterations in the composition of the dermal extracellular matrix and results in wrinkles, laxity, coarseness, mottled pigmentation, and histological changes that include increased epidermal thickness and connective tissue alteration (rittie and fisher 2002) . therefore, varieties of anti-photoaging or photoprotective compounds from algae and other marine organisms have been isolated. dhe from ec exerted a preventive effect against uvbinduced apoptosis in human keratinocyte (hacat) cells, indicating its benefit as a repair agent for skin damage caused by uvb (ryu et al. 2015) . fucodiphlorethol g from ec reduced uvb radiation-induced loss of mitochondrial membrane potential, the generation of apoptotic cells, and active caspase-9 expression. thus, it prevented oxidative damage-mediated apoptosis induced by uvb irradiation (kim et al. 2014f) . dhe from es inhibited cellular melanin content and the expression of melanogenesis-related proteins, including microphthalmia-associated transcription factor and tyrosinase and tyrosinase-related proteins trp-1 and trp-2, stimulating the phosphorylation of akt in a dose-dependent manner without affecting the phosphorylation of erk (lee et al. 2012b ). angiotensin-i-converting enzyme (ace) plays an important physiological role in the regulation of blood pressure by converting angiotensin i to angiotensin ii, a potent vasoconstrictor. some commercial drugs, such as captopril, ramipril, lisinopril, and enalapril, have unfortunate side effects like cough, taste disturbances, skin rashes or angioneurotic edema, so novel compounds such as phlorotannins have been derived from marine organisms as potential ace inhibitors . jung et al. (2006) reported that, among the seven enzymatically hydroxylated brown algal species, ec was a potent ace inhibitor with an ic 50 value of 0.3 lg/ml. eckol, pff-a, and dieckol from es showed potent ace inhibiting activity with ic 50 values of 70.82 ± 0.25, 12.74 ± 0.15, and 34.25 ± 3.56 lm, respectively, showing the importance of es. the human immunodeficiency virus (hiv) infects cells of the immune system by destroying or impairing their function, ultimately causing immune deficiency and opening the door to opportunistic infections, thereby causing acquired immune deficiency syndrome (aids). approximately 36.7 million people were living with hiv at the end of 2015. as of mid-2016, 18.2 million people were receiving antiretroviral treatment worldwide. seven out of ten pregnant women living with hiv received anti-retroviral treatment (who 2016). more than 30 approved commercial drugs are available for the treatment of aids. these drugs keep the disease under control; however, they are often associated with the emergence of cross-resistant hiv strains and various side-effects (sánchez and holguín 2014; haas et al. 2004 ). so, the need for potential nutraceuticals, especially from marine organisms, to fight this vicious disease is vital. 8,4 000 -dieckol from ec at noncytotoxic concentrations repressed hiv-1 activated syncytia formation, lytic effects, and viral p24 antigen production. furthermore, it selectively inhibited the activity of hiv-1 reverse transcriptase enzyme with 91% inhibition at 50 lm. therefore, it showed high potential and could be considered as a drug candidate for the development of a new generation of therapeutic agents (karadeniz et al. 2014) . other pharmacological activities include immunomodulatory, aphrodisiac, anti-hair loss, hearing repair, urinary tract infection remedy, hair growth performance, cosmetic whitening, osteoarthritis, and bone-related conditions. one study suggested that sulfated polysaccharides from ec induced t and b cell responses via both the jnk and nf-kb pathways . ecklonia bicyclis together with the novel drug tradamixina improved male sexual function in elderly men, particularly libido, mild-moderate erectile dysfunction, ejaculation function, and sexual quality of life (sansalone et al. 2014 ). purified polyphenols from ec increased fibroblast survival in human dermal papilla cells, preventing hair loss . dieckol isolated from ec suppressed ea.hy926 cell proliferation induced by vascular endothelial growth factor, demonstrating its anti-proliferative and anti-migratory effects through a mapk molecular signaling cascade and suggesting its potential as an anti-angiogenic candidate . dhe from ec enhanced osteoblast differentiation, as evidenced by increased cell proliferation, alkaline phosphatase activity, and intracellular cell mineralization, along with enhanced levels of osteoblastogenesis markers at 20 lm in mc3t3-e1 pre-osteoblasts. furthermore, dhe up-regulated phosphorylated erk and c-jnk, which were also stimulated by the bmp signaling pathway . a polyphenol-rich extract from ec showed potent radical-scavenging activity and decreased the abr threshold shifts, suggesting its potential as a preventive agent against temporary threshold shift . water-soluble sulfated fucans isolated from ec induced the degradation of ij-b and the phosphorylation of mapk in raw264.7 cells, implying that they might stimulate raw264.7 cells through the activation of the nf-jb and mapk pathways (cao et al. 2014) . the etoac fraction of ec resulted in elongation of the hair shaft in cultured human hair follicles and activated transition of the hair cycle from the telogen to the anagen phase in the dorsal skin of c57bl/6 mice. furthermore, it induced an increase in igf-1 expression in human dermal papilla cells (bak et al. 2013) . ec and its phlorotannins tpa, eckol, and dieckol attenuated the pathophysiological consequences of osteoarthritis and enhanced osteoblast differentiation, as indicated by increased alkaline phosphatase activity and raised levels of osteoblastogenesis, preventing osteoporosis . undoubtedly, ecklonia species and their active metabolites are potential candidates for drug development, as shown by their plethora of activities against various diseases. our review provides current information on the biological and pharmacological potential of this genus, which could be further used for the development of nutraceuticals. screening and study of the interactions between these algae and their constituents and human systems threatened by disease need to continue. therefore, we recommend rapid screening and isolation to develop novel functional ingredients from ecklonia species. the future of pharmaceuticals based on natural products seems promising. neuroinflammation, oxidative stress and the pathogenesis of alzheimer's disease review: hepatoprotective activity of spirulina species the jnk/nfjb pathway is required to activate murine lymphocytes induced by a sulfated polysaccharide from ecklonia cava dieckol, isolated from the edible brown algae ecklonia cava, induces apoptosis of ovarian cancer cells and inhibits tumor xenograft growth a sulfated polysaccharide of ecklonia cava inhibits the growth of colon cancer cells by inducing apoptosis dieckol, a phlorotannin of ecklonia cava, suppresses ige-mediated mast cell activation and passive cutaneous anaphylactic reaction dioxinodehydroeckol enhances the differentiation of osteoblasts by regulating the expression of phospho-smad1/5/8 anti-hiv-1 activity of phloroglucinol derivative, 6,6 0 -bieckol, from ecklonia cava evaluation of effective mmp inhibitors from eight different brown algae in human fibrosarcoma ht1080 cells ecklonia cava promotes hair growth radioprotective potential of mint: a brief review protective effects of ecklonia stolonifera extract on ethanol-induced fatty liver in rats the global epidemic of obesity: an overview water soluble sulfated-fucans with immune-enhancing properties from ecklonia cava possible role of oxidative stress in the pathogenesis of hypertension dieckol, an edible seaweed polyphenol, retards rotenone-induced neurotoxicity and a-synuclein aggregation in human dopaminergic neuronal cells protective effect of a purified polyphenolic extract from ecklonia cava against noise-induced hearing loss: prevention of temporary threshold shift improved antioxidant activities of brown seaweed ecklonia radiata extracts prepared by microwave-assisted enzymatic extraction impact of extraction processes on prebiotic potential of the brown seaweed ecklonia radiata by in vitro human gut bacteria fermentation marine polyphenol phlorotannins promote non-rapid eye movement sleep in mice via the benzodiazepine site of the gabaa receptor the cytoprotective effects of ethanol extract of ecklonia cava against oxidative stress are associated with upregulation of nrf2-mediated ho-1 and nqo-1 expression through activation of the mapk pathway in vitro antibacterial and anti-inflammatory properties of seaweed extracts against acne inducing bacteria, propionibacterium acnes suppression of nf-jb by dieckol extracted from ecklonia cava negatively regulates lps induction of inducible nitric oxide synthase gene dieckol, a major phlorotannin in ecklonia cava, suppresses lipid accumulation in the adipocytes of high-fat diet-fed zebrafish and mice: inhibition of early adipogenesis via cell-cycle arrest and ampka activation multifunctional activity of polyphenolic compounds associated with a potential for alzheimer's disease therapy from ecklonia cava comparison of ecklonia cava, ecklonia stolonifera and eisenia bicyclis for phlorotannin extraction oncogenes and cancer dieckol attenuates microglia-mediated neuronal cell death via erk, akt and nadph oxidase-mediated pathways enrichment of enzymatically mineralized gellan gum hydrogels with phlorotannin-rich ecklonia cava extract seanol ò to endow antibacterial properties and promote mineralization effects of gametophytes of ecklonia kurome on the levels of glucose and triacylglycerol in db/db, prediabetic c57bl/6j and ifn-c ko mice brown alga ecklonia cava polyphenol extract ameliorates hepatic lipogenesis, oxidative stress, and inflammation by activation of ampk and sirt1 in high-fat diet-induced obese mice cancer incidence and mortality worldwide: sources, methods and major patterns in globocan 2012 structure of an anti-plasmin inhibitor, eckol, isolated from the brown alga ecklonia kurome okamura and inhibitory activities of its derivatives on plasma plasmin inhibitors anti-plasmin inhibitor. vi. structure of phlorofucofuroeckol a, a novel phlorotannin with both dibenzo-1, 4-dioxin and dibenzofuran elements, from ecklonia kurome okamura premotor and non-motor features of parkinson's disease the skin microbiome phloroglucinol protects small intestines of mice from ionizing radiation by regulating apoptosis-related molecules: a comparative immunohistochemical study pharmacogenetics of efavirenz and central nervous system side effects: an adult aids clinical trials group study antioxidative effect of proteolytic hydrolysates from ecklonia cava on radical scavenging using esr and h 2 o 2 -induced dna damage om fucus buccinalis lin acidic oligosaccharide sugar chain, a marine-derived acidic oligosaccharide, inhibits the cytotoxicity and aggregation of amyloid beta protein alpha-synuclein oligomers-neurotoxic molecules in parkinson's disease and other lewy body disorders seapolynol extracted from ecklonia cava inhibits adipocyte differentiation in vitro and decreases fat accumulation in vivo chemical structures and bioactivities of sulfated polysaccharides from marine algae the inhibitory effects of eckol and dieckol from ecklonia stolonifera on the expression of matrix metalloproteinase-1 in human dermal fibroblasts eckol enhances heme oxygenase-1 expression through activation of nrf2/jnk pathway in hepg2 cells angiotensin-converting enzyme i inhibitory activity of phlorotannins from ecklonia stolonifera inhibitory activities of extracts from several kinds of seaweeds and phlorotannins from the brown alga ecklonia stolonifera on glucose-mediated protein damage and rat lens aldose reductase kinetics and molecular docking studies of an antidiabetic complication inhibitor fucosterol from edible brown algae eisenia bicyclis and ecklonia stolonifera inhibitory effects of histamine production in mackerel muscle by medicinal herbs and seaweed extracts protective effect of the edible brown alga ecklonia stolonifera on doxorubicininduced hepatotoxicity in primary rat hepatocytes anti-adipogenic activity of the edible brown alga ecklonia stolonifera and its constituent fucosterol in 3t3-l1 adipocytes kinetics and molecular docking studies of fucosterol and fucoxanthin, bace1 inhibitors from brown algae undaria pinnatifida and ecklonia stolonifera antibacterial activities of marine epibiotic bacteria isolated from brown algae of japan antioxidant and anti-inflammatory activities of ventol, a phlorotannin-rich natural agent derived from ecklonia cava, and its effect on proteoglycan degradation in cartilage explant culture a new phlorotannin from the brown alga ecklonia stolonifera inhibitory phlorotannins from the edible brown alga ecklonia stolonifera on total reactive oxygen species (ros) generation protective effect of marine algae phlorotannins against aaph-induced oxidative stress in zebrafish embryo dieckol isolated from brown seaweed ecklonia cava attenuates type ii diabetes in db/db mouse model protective effect of dieckol isolated from ecklonia cava against ethanol caused damage in vitro and in zebrafish model phlorotannin-rich ecklonia cava reduces the production of betaamyloid by modulating alpha-and gamma-secretase expression and activity dieckol, a component of ecklonia cava, suppresses the production of mdc/ccl22 via down-regulating stat1 pathway in interferon-c stimulated hacat human keratinocytes acetylcholinesterase inhibitory activity of phlorotannins isolated from the brown alga, ecklonia maxima (osbeck) papenfuss anti-hiv-1 activity of phlorotannin derivative 8,4 000 -dieckol from korean brown alga ecklonia cava phlorotannins suppress adipogenesis in pre-adipocytes while enhancing osteoblastogenesis in pre-osteoblasts role of erk/mapk signaling pathway in antiinflammatory effects of ecklonia cava in activated human mast cell line-1 cells enzyme-treated ecklonia cava extract inhibits adipogenesis through the downregulation of c/ebpa in 3t3-l1 adipocytes hepatoprotective constituents of the edible brown alga ecklonia stolonifera on tacrine-induced cytotoxicity in hepg2 cells isolation and identification of phlorotannins from ecklonia stolonifera with antioxidant and anti-inflammatory properties phlorofucofuroeckol a inhibits the lps-stimulated inos and cox-2 expressions in macrophages via inhibition of nf-jb, akt, and p38 mapk evaluation of inhibitory effect of phlorotannins from ecklonia cava on triglyceride accumulation in adipocyte triphlorethol-a from ecklonia cava upregulates the oxidant sensitive 8-oxoguanine dna glycosylase 1 cytoprotective effect of eckol against oxidative stress-induced mitochondrial dysfunction: involvement of the foxo3a/ampk pathway protective effect of fucoidan against aaph-induced oxidative stress in zebrafish model the edible brown seaweed ecklonia cava reduces hypersensitivity in postoperative and neuropathic pain models in rats fucodiphlorethol g purified from ecklonia cava suppresses ultraviolet b radiationinduced oxidative stress and cellular damage inhibitory effects of brown algae extracts on histamine production in mackerel muscle via inhibition of growth and histidine decarboxylase activity of morganella morganii protective effect of marine brown algal polyphenols against oxidative stressed zebrafish with high glucose first evidence that ecklonia cavaderived dieckol attenuates mcf-7 human breast carcinoma cell migration synergistic antibacterial activity of ecklonia cava extract against anti-biotic resistant enterococcus faecalis winogradskyella eckloniae sp. nov., a marine bacterium isolated from the brown alga ecklonia cava 0 -bieckol suppresses inflammatory responses by downregulating nuclear factor-jb activation via akt, jnk, and p38 mapk in lps-stimulated microglial cells a marine algal polyphenol, dieckol, attenuates blood glucose levels by akt pathway in alloxan induced hyperglycemia zebrafish model dieckol, a phlorotannin isolated from a brown seaweed, ecklonia cava, inhibits adipogenesis through amp-activated protein kinase (ampk) activation in 3t3-l1 preadipocytes evaluation of marine algae wakame (undaria pinnatifida) and kombu (laminaria digitata japonica) as food supplements induction of apoptosis by phloroglucinol derivative from ecklonia cava in mcf-7 human breast cancer cells edible brown alga ecklonia cava derived phlorotannin-induced anti-adipogenic activity in vitro minerals, polysaccharides and antioxidant properties of aqueous solutions obtained from macroalgal beachcasts in the noto peninsula periodontal disease and obesity seaweeds as a source of nutritionally beneficial compounds-a review in vitro antiviral activity of phlorotannins isolated from ecklonia cava against porcine epidemic diarrhea coronavirus infection and hemagglutination anti-cholinesterases and memory improving effects of vietnamese xylia xylocarpa inhibitory effects of polyphenols isolated from marine alga ecklonia cava on histamine release efficacy and safety of a dieckol-rich extract (ag-dieckol) of brown algae, ecklonia cava, in prediabetic individuals: a double-blind, randomized, placebocontrolled clinical trial isolation and identification of phlorotannins from ecklonia stolonifera with antioxidant and hepatoprotective properties in tacrine-treated hepg2 cells dioxinodehydroeckol inhibits melanin synthesis through pi3k/ akt signalling pathway in alpha-melanocyte-stimulating hormone-treated b16f10 cells recent advances in pharmacological research on ecklonia species: a review 1003 anti-inflammatory effect of fucoidan extracted from ecklonia cava in zebrafish model alleviating effects of baechu kimchi added ecklonia cava on postprandial hyperglycemia in diabetic mice radio-protective effect of polysaccharides isolated from lactobacillus brevis-fermented ecklonia cava effect of baechu kimchi added ecklonia cava extracts on high glucose-induced oxidative stress in human umbilical vein endothelial cells microrna134 mediated upregulation of jnk and downregulation of nf-kb signaling are critically involved in dieckol induced antihepatic fibrosis a prebiotic role of ecklonia cava improves the mortality of edwardsiellatarda-infected zebrafish models via regulating the growth of lactic acid bacteria and pathogen bacteria a prebiotic effect of ecklonia cava on the growth and mortality of olive flounder infected with pathogenic bacteria a phlorotannin constituent of ecklonia cava alleviates postprandial hyperglycemia in diabetic mice fucosterol, isolated from ecklonia stolonifera, inhibits adipogenesis through modulation of foxo1 pathway in 3t3-l1 adipocytes phlorotannins as bioactive agents from brown algae dieckol as a novel antiproliferative and anti-angiogenic agent and computational antiangiogenic activity evaluation projected neurodegenerative disease mortality in the united states caffeic acid phenethyl ester alleviates asthma by regulating the airway microenvironment via the ros-responsive mapk/akt pathway insulin therapy and hypoglycemia selecting australian marine macroalgae based on the fatty acid composition and anti-inflammatory activity nitric oxide: physiology, pathophysiology, and pharmacology protective effect of phlorotannin components phloroglucinol and eckol on radiation-induced intestinal injury in mice protein tyrosine phosphatase 1b and a-glucosidase inhibitory phlorotannins from edible brown algae, ecklonia stolonifera and eisenia bicyclis a high-throughput screen for inhibitors of the prolyl isomerase, pin1, identifies a seaweed polyphenol that reduces adipose cell differentiation bactericidal activity of phlorotannins from the brown alga ecklonia kurome the influence of sulfate content and molecular weight of a fucan sulfate from the brown seaweed ecklonia kurome on its antithrombin activity an anticoagulant fucoidan from the brown seaweed ecklonia kurome inhibition of the generation of thrombin and factor xa by a fucoidan from the brown seaweed ecklonia kurome cancer statistics in korea: incidence, mortality, survival, and prevalence in 2013 neuroprotective effects of marine algae effects of phloroglucinol isolated from ecklonia stolonifera on the acetaminophen-metabolizing enzyme system in rat radioprotective properties of eckol against ionizing radiation in mice phloroglucinol (pg) purified from ecklonia cava attenuates radiation-induced apoptosis in blood lymphocytes and splenocytes dieckol, a sars-cov 3cl(pro) inhibitor, isolated from the edible brown algae ecklonia cava 0 -bieckol isolated from ecklonia cava protects oxidative stress through inhibiting expression of ros and proinflammatory enzymes in high-glucose-induced human umbilical vein endothelial cells 0 -bieckol protects insulinoma cells against high glucose-induced glucotoxicity by reducing oxidative stress and apoptosis polyphenol-rich fraction of ecklonia cava improves nonalcoholic fatty liver disease in high fat diet-fed mice antimicrobial action of compounds from marine seaweed oxidative stress in the pathogenesis of colorectal cancer: cause or consequence? antibacterial activity of the extracts of marine red and brown algae algaebacteria interactions: evolution, ecology and emerging applications global prevalence of diabetes: estimates for the year 2000 and projections for 2030 potential antiradical and alpha-glucosidase inhibitors from ecklonia maxima (osbeck) papenfuss uv-light-induced signal cascades and skin aging anti-obesity drugs: past, present and future dioxinodehydroeckol protects human keratinocyte cells from uvb-induced apoptosis modulated by related genes bax/bcl-2 and caspase pathway protective effects of dieckol on n-nitrosodiethylamine induced hepatocarcinogenesis in rats drug resistance in the hiv-1-infected paediatric population worldwide: a systematic review alga ecklonia bicyclis, tribulus terrestris, and glucosamine oligosaccharide improve erectile function, sexual quality of life, and ejaculation function in patients with moderate mild-moderate erectile dysfunction: a prospective, randomized, placebo-controlled, single-blinded study jp renew distributors 1906 lombard street heparinoid-active sulphated polysaccharides from marine algae as potential blood anticoagulant agents inhibitory activity of brown algal phlorotannins against hyaluronidase antioxidant activities of phlorotannins isolated from japanese laminariaceae enhancement of human hair growth using ecklonia cava polyphenols in vitro screening for anti-dementia activities of seaweed extracts inhibitory effect of extracts from the brown alga, ecklonia stolonifera, on enzymes responsible for allergic reactions and degranulation in rbl-2h3 cells flavonoids for allergic diseases: present evidence and future perspective potential pharmacological applications of polyphenolic derivatives from marine brown algae oxidative stress and its role in skin disease marine algae-mediated synthesis of gold nanoparticles using a novel ecklonia cava isolation and identification of anti-inflammatory compounds from ethyl acetate fraction of ecklonia stolonifera and their anti-inflammatory action prevent hiv, test and treat all-who support for country impact angiotensin-i-converting enzyme (ace) inhibitors from marine resources: prospects in the pharmaceutical industry phlorotannins from ecklonia cava (phaeophyceae): biological activities and potential health benefits exploiting biological activities of brown seaweed ecklonia cava for potential industrial applications: a review anti-diabetic effect of polyphenols from brown alga ecklonia kurome in genetically diabetic kk-ay mice ecklonia cava polyphenol has a protective effect against ethanolinduced liver injury in a cyclic amp-dependent manner 0 -bieckol, isolated from edible brown algae, exerts its anti-inflammatory effects through inhibition of nf-jb signaling and ros production in lps-stimulated macrophages brown algae phlorotannins enhance the tumoricidal effect of cisplatin and ameliorate cisplatin nephrotoxicity phloroglucinol attenuates the cognitive deficits of the 5xfad mouse model of alzheimer's disease protective effect of brown alga phlorotannins against hyper-inflammatory responses in lipopolysaccharide-induced sepsis models dieckol, isolated from ecklonia stolonifera, induces apoptosis in human hepatocellular carcinoma hep3b cells inhibitory effect of chlorophyll c2 from brown algae, sargassum horneri, on degranulation of rbl-2h3 cells isolation and structural determination of two novel phlorotannins from the brown alga ecklonia kurome okamura, and their radical scavenging activities phlorofucofuroeckol a isolated from ecklonia cava alleviates postprandial hyperglycemia in diabetic mice acknowledgements this research was supported by the basic science research program through the national research foundation of korea (nrf), funded by the ministry of education (2012r1a6a1028677). conflicts of interest the authors declare no conflicts of interest. key: cord-286303-wo6356vq authors: khanna, varun; li, lei; fung, johnson; ranganathan, shoba; petrovsky, nikolai title: prediction of novel mouse tlr9 agonists using a random forest approach date: 2019-12-20 journal: bmc mol cell biol doi: 10.1186/s12860-019-0241-0 sha: doc_id: 286303 cord_uid: wo6356vq background: toll-like receptor 9 is a key innate immune receptor involved in detecting infectious diseases and cancer. tlr9 activates the innate immune system following the recognition of single-stranded dna oligonucleotides (odn) containing unmethylated cytosine-guanine (cpg) motifs. due to the considerable number of rotatable bonds in odns, high-throughput in silico screening for potential tlr9 activity via traditional structure-based virtual screening approaches of cpg odns is challenging. in the current study, we present a machine learning based method for predicting novel mouse tlr9 (mtlr9) agonists based on features including count and position of motifs, the distance between the motifs and graphically derived features such as the radius of gyration and moment of inertia. we employed an in-house experimentally validated dataset of 396 single-stranded synthetic odns, to compare the results of five machine learning algorithms. since the dataset was highly imbalanced, we used an ensemble learning approach based on repeated random down-sampling. results: using in-house experimental tlr9 activity data we found that random forest algorithm outperformed other algorithms for our dataset for tlr9 activity prediction. therefore, we developed a cross-validated ensemble classifier of 20 random forest models. the average matthews correlation coefficient and balanced accuracy of our ensemble classifier in test samples was 0.61 and 80.0%, respectively, with the maximum balanced accuracy and matthews correlation coefficient of 87.0% and 0.75, respectively. we confirmed common sequence motifs including ‘cc’, ‘gg’,‘ag’, ‘cccg’ and ‘cggc’ were overrepresented in mtlr9 agonists. predictions on 6000 randomly generated odns were ranked and the top 100 odns were synthesized and experimentally tested for activity in a mtlr9 reporter cell assay, with 91 of the 100 selected odns showing high activity, confirming the accuracy of the model in predicting mtlr9 activity. conclusion: we combined repeated random down-sampling with random forest to overcome the class imbalance problem and achieved promising results. overall, we showed that the random forest algorithm outperformed other machine learning algorithms including support vector machines, shrinkage discriminant analysis, gradient boosting machine and neural networks. due to its predictive performance and simplicity, the random forest technique is a useful method for prediction of mtlr9 odn agonists. toll-like receptors (tlrs) represent an ancient evolutionary host immune defense system. there are 13 expressed tlr genes in mice (10 in humans), and each is devoted to recognizing a distinct set of pathogen associated molecular patterns (pamps) that are not found in healthy vertebrate cells, making them an important tool to help fight infections [1] . tlrs 1, 2, 4, 5 and 6 are extracellular and are situated in the plasma membrane where they bind bacterial cell wall components such as lipoteichoic acids, lipopolysaccharides, lipoproteins, and flagella. tlrs 3, 7, 8, 9 are located in endosomes where they recognize specific nucleic acid sequences expressed by various pathogens [2] . the extracellular signaling domain of tlr9 forms a horseshoe shaped dimer that forms a sandwich that clasps two cpg oligonucleotides (odn) resulting in the cytoplasmic domains coming into close proximity thereby triggering downstream signaling [2] . upon activation, tlr9 triggers an innate immune response characterized by the production of pro-inflammatory cytokines such as tnf-α, il-1, il-6, and il-12. some synthetic single-stranded odns that contain unmethylated cpg motifs mimic bacterial dna and can bind and activate tlr9 leading to cytokine secretion and enhancement of adaptive immune responses. synthetic tlr9-active odns have shown utility as vaccine adjuvants and anti-cancer immunotherapeutic agents. to identify a good tlr9 ligand, typically a large library of odns needs to be synthesized and screened on cell lines, which is a time consuming and expensive task. we hypothesized that modern in silico high-throughput screening (hts) methods may improve the ability to identify novel highly active tlr9 ligands. in silico screening, also known as virtual screening (vs), has been widely used to enrich datasets with compounds that have a higher probability of binding to the target of interest [3] [4] [5] , and has an advantage over traditional screening or physical hts due to its massively parallel processing ability; hence millions of compounds can be assessed economically in parallel. this is particularly important when the search space for potential odns tlr9 ligands is taken into consideration. a typical singlestranded odn tlr9 agonist is 24 nucleotides in length, which amounts to 4 24 total number of possible odns. vs methods are of two major classes based on the availability of structural information. if the 3d structure of a receptor is known, structure-based virtual screening (sbvs) [6] techniques such as homology modeling, molecular docking and molecular dynamics can be used. however, if the structural information of the receptor is lacking, then ligand-based virtual screening (lbvs) [7] techniques such as quantitative structure-activity relationship and machine learning are more appropriate. sbvs involves molecular complex optimization to find the most favorable 3d binding conformation of the ligand. consequently, sbvs is unsuitable for highthroughput screening of ligands like 24-mer odns, which have over 100 rotatable bonds. on the other hand, lbvs is computationally inexpensive, easy to use and might therefore be useful in the screening of tlr9 activating odns. in a recent review, murgueitio et al. [8] discussed the use of various computational approaches to investigate the structure and function of tlr receptors. to discover potential tlr ligands. zatsepin et al. [9] screened a library of 1.8 million commercially available compounds to discover tlr9 antagonists by using computational chemistry and cell-based assays. the authors reported 21 potential tlr9 antagonists with ic50 lower than 10 μm, with five of them having ic50 values below 1 μm. zhou et al. [10] constructed a 3d structure of human tlr9 ectodomains, complexed with cpg odns using homology modeling, then used molecular docking to study the interactions between tlr9 and the odns. they reported that leucine rich region (lrr)-11 was the main region in tlr9 responsible for odn binding. the authors further reported that five positively charged residues within lrr11 were specifically involved in the odn binding to tlr9. nagpal et al. [11] reported a support vector machine model to predict odns with tlr9 activity with the model achieving a maximum matthews correlation coefficient of 0.75 with an accuracy of 87%. tlr9 ligand prediction tools require availability of well-annotated odn datasets with experimentally determined tlr9 activity data. machine learning (ml) based techniques such as decision trees, random forest, support vector machines and neural networks can then be applied to such odn datasets. ml is an umbrella term for statistical models built to discover patterns in existing data to explain unseen data. ml models are very powerful tools that have been used in the past to predict and classify the pharmacokinetics or toxicological profiles of compounds [12] , predict biological activities or toxicity [13] and assist in screening and optimization of compounds [5] . to our knowledge, this is the first report on the use of random forest-based approaches to predict novel mtlr9 ligands based on an in-house experimentally validated odn dataset, with 91% prediction accuracy shown by experimental validation. the main goal of this study was to build a ml model that could distinguish odns that have high activity for mtlr9 from odns with low activity. we used 117 odns with known high mtlr9 activity, as positive examples while 274 odns with low activity were used as negative examples. we first analysed the dataset to understand the occurrence of sequence motifs in mtlr9 activating odns. we observed an uneven distribution of motifs with a few motifs such as 'gg' or 'cc' present in 57% of the odns in the high activity group compared to only 13% of the odns in the low activity group. figure 1 shows the percentage of odns in the top 20 motifs arrange in a clockwise manner, based on the absolute difference in the percentage of occurrence in high and low mtlr9 activity groups of odns. all motifs having an absolute difference above 10% are shown in additional file 1. we further analyzed the effect of motif occurrence on the mtlr9 activity score in the high and low activity groups of odns in the dataset. using the mann-whitney u test we compared the median mtlr9 activity score of odns with a motif to those without the motif for the two classes and calculated the p values. the significance threshold was set at 0.05. figure 2 shows the effect of top 20 motifs occurrence in high (fig. 2a) and low (fig. 2b ) mtlr9 active group of odns. the darker colored bars stand for a significant difference in the median mtrl9 activity score (p < 0.05) due to the presence of the motif in the odns. the dotted line is the median mtlr9 score of 0.53 and 0.18 for the high and low activity groups of odns, respectively. within the low activity group (additional file 2), we found that presence of motifs such as 'cc', 'gg', 'ggc', 'gcc', 'cccg' and 'cggc' significantly increases the median mtlr9 activity score, while the presence of motifs e.g. 'tgt', 'cgcgt' and 'tct' further lowers the activity of odns. in contrast, we found presence of 'cgtt' motif to significantly improve while 'ag' motif to significantly decrease the median mtlr9 activity score of the odns in the high activity group (additional file 3). since there was no single motif that could account for the mtlr9 activity score of the odns, we surmised that the combination of motifs and their interaction with the tlr9 receptor was responsible for determining overall mtlr9 activity. mean classification levels achieved by all algorithms in different k-fold cross validation schemes when applied to 20 bootstrap test samples obtained using the down-sampling technique are shown in fig. 3 . we found that overall rf model either outperformed or was on par with the other prediction algorithms in all four cross validation schemes. in five-fold cross validation the best rates were achieved by the rf and svm model with a maximum balanced accuracy of 95.65% and mcc of 0.91 (additional file 4). the mean balanced accuracy and mean mcc for rf model in five-fold cross validation was 77.8% and 0.57, respectively, with standard deviations of 0.08 and 0.15, respectively (table 1 ). in ten-fold cross validation, rf and gbm achieved the best results with the maximum balanced accuracy and mcc of 89.13% and 0.78, respectively (additional file 5). the mean balanced accuracy and mcc for the rf model in ten-fold cross validation was 78.9% and 0.60, respectively, with standard deviations of 0.06 and 0.11, respectively (table 1 ). in 15fold cross validation the best results were achieved by rf and svm with the maximum balanced accuracy and mcc of 86.9% and 0.74, respectively (additional file 6). the mean balanced accuracy and mcc for the rf model in 15-fold was 77.0% and 0.55, respectively with standard deviations of 0.06 and 0.11, respectively (table 1 ). in 20fold cross validation random forest achieved the best result with the maximum balanced accuracy and mcc of 87.0% and 0.75, respectively (additional file 7). the mean balanced accuracy and mcc of rf model was 79.7% and 0.61, respectively, with standard deviations of 0.05 and 0.09, respectively (table 1) . overall, the rf algorithm outperformed in all other ml methods, for different cross-validation values. we therefore selected rf with the 20-fold cross-validation scheme, having maximum mean balanced accuracy and mcc and minimum standard deviation on both measures, to perform the fig. 2 the effect of top 20 motifs in the high (a) and low (b) mtlr9 activity group of odns in the dataset. the darker bars represent a significant difference in the median mtlr9 activity score due to the presence of motif in the odns. the dotted line shows the median mtlr9 activity of 0.53 and 0.18 for the odns in the high and low activity groups, respectively, in the dataset mtlr9 activity predictions for the randomly generated odn dataset. external validation is the final step to evaluate the realistic performance of any prediction model. in this technique, the performance of the model is evaluated on a new dataset not used in training or testing the model. to rigorously evaluate the performance of our model, we randomly generated 6000 24-mer odn sequences using an in-house written python script and then screened and ranked these randomly generated odn for mtlr9 activity using our rf model. these odns were not present in our original dataset of 396 odns used for model building or training, and as they were virtual we had no prior knowledge of their likely mtlr9 activity at the time of model prediction. our rf model predicted 545 of these 6000 random odns to be of high activity and we selected the top 100 for chemical synthesis, and then experimental tested them for mtlr9 activity using the raw-blue reporter cell line that expresses mtlr. ninety-one (91%) of the predicted high activity odns had a mtlr9 activity value above 0.4, confirming the high accuracy of the model in predicting odn sequences with positive mtlr9 activity (fig. 4 ). this demonstrates that our mtlr9-specific rf prediction model is rigorous, with a strong performance on making predictions on a completely independent dataset. in this study we demonstrated the feasibility of using an rf model for in silico screening of synthetic odns to detect high activity mtlr9 agonists. multiple sequence features such as simple counts of nucleotides, the distance between motifs and graphically derived features like the moment of inertia were calculated before building the rf model. we observed higher occurrence of several motifs such as 'cggc', 'cccg', 'gcc', 'cgg', 'ggc', 'ccg', 'ccc', 'gg' and 'cc' in high activity as compared to low activity odns. this means that these cytosine and guanine rich motifs along with the key unmethylated cpg dinucleotide contribute to strong mouse tlr9 activation. interestingly, this is in contrast with the thymine rich motifs reported for tlr9 fig. 3 mean and standard deviation of balanced accuracy rates of the five classifiers on the twenty bootstrap test samples using k-fold crossvalidation scheme. mean balanced accuracy rate of rf model was greater than all five algorithms in all the folds stimulatory odns by nagpal et al. [11] . this may be due the fact that our odn training set was mouse specific whereas the dataset used by nagpal et al. [11] was not specific to any organism. on further analysis we found 15 and 4 motifs which significantly increased, or decreased, respectively, mtlr9 activity in the low activity group (additional file 2), whereas, we found only 3 and 4 motifs in the high activity odns which significantly (p value < 0.05) increased or decreased, respectively, mtlr9 activity (additional file 3). furthermore, we discovered motifs which significantly decreased mtlr9 activity in both low and high groups. for example, 'cgcgtg' and sub motifs like 'gcgtg' and 'cgcgt', decreased the activity of odns in both the high and low groups. however, we were unable to identify motifs that increased mtlr9 activity for both groups of odns. this suggests that a combination of motifs might be required to increase activity of odns in the high group whereas the activity of low odns can be improved even by inclusion of a single motif. cooccurrence of motifs and their effect on mouse tlr9 activity can be analyzed in the future to discover combinations of motifs responsible for the increase in the activity of odns in both groups. the performance of the rf model was compared to other methods, which were trained on the same data. the average classification accuracy achieved by all the methods when applied to 20 bootstrap test samples in four different cross-validation schemes is shown in fig. 3 . the results demonstrated that the rf model had the superior performance on the test datasets in most of the scenarios. the gbm and svm classifiers also had reasonable classification accuracy rates, however, rf outperformed them in 20-fold cross validation scheme. the selected rf model on average correctly classified 79.1% of the odns in the training set with high activity for mtlr9 and 80.2% of odns with low activity. the rf thereby achieved an overall balanced accuracy of 79.7%. finally, the rf model was used to virtually screen 6000 randomly generated odns from which it predicted 545 odns to have high activity for mtlr9. due to large number of predicted positive hits, the top 100 odns were selected for synthesis and testing for mtlr9 activity in vitro. ninety one out of the 100 synthesized odns were found to have mtlr9 activity above the cutoff of 0.4 for high activity odns confirming the prediction potential of the rf model. however, fig. 4 shows that the majority of predicted ligands had an activity value ranging from 0.5 to 0.7, which indicates that the model might need to be further fine-tuned to get even higher activity ligands, with a much larger dataset than the randomly generated 6000 oligonucleotides screened to find high activity ligands. in this study we found several sequence motifs that help explain the mtlr9 activity of cpg odns. motifs including 'cgtt', 'ggc', 'gcc' and 'cccg' significantly improved, whereas motifs such as 'ag', 'tct' and 'cgcgt' significantly decreased, the activity of mtlr9 odns. further, we developed and validated an rf model for predicting odns with mtlr9 activity. the results showed that the rf method was well suited for predicting high activity mtlr9 specific odns and outperformed various other learning algorithms such as svm, sda, nn and gbm. the model was used to screen a random library of 6000 odns and correctly identified 91 out of 100 odns that were subsequently confirmed to have mtlr9 activity. this shows the power of machine learning models for discovering novel tlr9 agonists. the lead mtlr9 active odn candidates from the above studies are now being tested as vaccine adjuvants and anti-cancer agents in relevant mouse models. the quality of the training dataset determines the quality of the resulting machine learning model. missing or insufficient data, mislabeling of the target variable, and irrelevant features may complicate the learning task and hinder the performance of the trained model. the sequences of odns with experimentally determined mtlr9 activity were obtained from in-house data we generated on synthesized odns that were characterized using a mouse tlr9 expressing reporter cell line (raw-blue cells, invivogen, usa). the dataset consisted of 396 odns with mtlr9 activity values ranging from 0.0 (no activity) to 1.14 (high activity). the odns were grouped into two classes (fig. 5) based on their respective activity value (i.e. 0.4 and above: high activity and below 0.4: low activity), resulting in a high activity group (count 117) and a low activity group (count 279). to ensure data quality, it is customary to check and remove any outliers, impute the missing data, check, and assign the variables the correct datatype. our dataset had neither missing values nor outliers and therefore, no further action was required in cleaning the dataset. however, to avoid overtraining the model with similar odns, the diversity of the dataset was increased by limiting the similarity within the group. this was achieved by clustering the odns within a group using the binary fingerprint features we developed during this study and applying a clustering cutoff of 0.85 to remove similar odns. this resulted in the removal of five odns from the low activity group with 274 remaining. all odns in the high group (count 117) were dissimilar enough not to breach the similarity cutoff and were retained. in our training dataset, the number of odns with low mtlr9 activity was approximately 2.5 times more than the number of odns with high mtlr9 activity. therefore, we used the down-sampling technique to balance the dataset, so that 50% of the samples were derived from the set of odns with high activity and 50% from the set of odns with low activity. subsequently, the down-sampled dataset was subdivided into training (80%) and testing (also known as validation) sets (20%), using a random sampling technique and the odns in the test set were excluded from model training. in order to choose the best classifier with k-fold cross validation, the performance of our models were measured using 20 down-sampled test sets. the overall methodology adopted in the study is shown in fig. 6 . in table 2 , we present the composition of the dataset used in this study. for each instance, the training dataset was composed of 188 odns (derived from 94 odns with high and low mtlr9 activity each). the test dataset used to evaluate the performance of a model was composed of 46 odns (23 each from the two groups of high and low mtlr9 activity). for the prediction set, we used an in-house python script to randomly generate 6000 24-mer odns, to capture the diversity of the 24-mer cpg-odn universe. every odn in the prediction set was classified using the selected model and crossvalidation scheme in a loop. for the final prediction, a consensus of the 20 predictions were taken for each odn in the prediction set. finally, the top 100 high activity predicted odns were selected for synthesis and experimental testing using the raw-blue reporter cell line assay. the training and test set odns along with experimental activity information are available in additional file 8. the measured mtlr9 activity value of all the synthesized 24-mer odns in the dataset. the odns were divided into two groups of high (shown in purple) and low (shown in green) activity using a cutoff score of 0.4, based on the optimal density (od) results from the raw-blue reporter cell assay it is possible to generate a large number of features for the odn sequence data that can be used to construct machine learning models. however, there are several problems in using all the possible features as (i) some of the features may be highly correlated (ii) some may not be relevant and may contribute to the noise in the model and (iii) using a large number of features may lead to overfitting. additionally, constructing models with many features is computationally demanding [14] . therefore, one of the most important aspects of creating a good ml model is the choice of appropriate features that can help explain the behavior of interest based on occam's razor principle (i.e. simple models are more likely to be closer to reality than complex models.) [15] . while there are a variety of features used in bioinformatics for sequence data, we used the binary fingerprint features and numerical features, including count and position of motifs, distance of the motifs with respect to the start position and graphically derived features such as the moment of inertia and radius of gyration, to train the model [16] . to generate fingerprint features, a fasta formatted file containing all high activity odn sequences was analysed using an in-house perl subroutine, to chop each sequence into motifs of increasing length from two to six nucleotides and record the start positions of the motifs. for example, with a small hypothetical odn 'tcg' of three nucleotides, two dinucleotides motifs tc1, cg2 and a trinucleotide tcg1 motif were generated. finally, a dictionary of the motifs with at least 10% difference in the occurrence rate in low and high group of odns (count 67) was prepared. subsequently, the dictionary was used to generate the binary fingerprint pattern for each sequence, where 1 showed the presence of a motif while 0 indicated its absence. different patterns of nucleotide usage in odns may lead to varied mtlr9 activity. therefore, all nucleotide characters (a, t, g, c) were counted in a sequence and the perl built-in dictionary data structure, hash, was used to store the count of each nucleotide. ambiguous nucleotide characters or gaps were ignored if present. calculating the distance between motifs with respect to their start positions the most commonly occurring motifs were used to calculate the distance between motif features along with their specific location. to map the position of a motif in the odns, the sequence of each odn was scanned for the presence of a motif and all the positions where each motif occurs were recorded. using eqs. (1)-(3), the distance between the second and first, third and first and the third and second occurrence of the motifs were calculated for all the motifs. where d_motif is the distance, p3, p2 and p1 are the position 3, position 2 and position 1 of the motif respectively, and 'n' is the number of nucleotides before the latter motif. in the case of the absence of a motif, 0 was substituted in the equation. it is important to keep 'n' in the equation to provide the specific location of the motifs within an odn, because the calculated distance between motifs could be same in several odns. for example, in a sequence s1 = tatgcgttcg-tacttgatctgac, the distance between cg motifs is 9-5 = 4. similarly, for another sequence s2 = tgctttcttgtcgtgcgggctgt, the distance between the cg motifs is 16-12 = 4, again. however, the descriptor d_cg2_1 value for s1 and s2 are 12 and 19, respectively, with the addition of n to the simple distance formula of d_motif. the graphical representation of dna sequences have been used for many applications including assessing phylogenetic relationships [17] , characterization of neuraminidase gene in h5n1 avian flu [18] and for describing similarity/dissimilarity of dna sequences [4] . in order to derive features, the 24-mer odn sequences were represented as a 2d-graph, as previously described [16] . briefly, each base in the sequence is represented as a material point on the graph which is treated as a rigid body and follows the rules of newtonian dynamics. numerical features such as the center of mass (μ x , μ y ), the principal moment of inertia(i 11, i 22 ) and radius of gyration (r g ) were calculated for each sequence as described in [16] . there are several feature selection methods used in machine learning to remove redundant or irrelevant features. these can be broadly divided into filter methods (e.g. correlation matrix, information gain, chi-square score, principal component analysis, regression coefficients, variable importance) and wrapper methods (e.g. forward/backward selection, randomized methods that combine pls with the genetic algorithm or monte carlo algorithm) [19] [20] [21] . filter methods are easy to implement because there is no learning involved and depend only on the application of a cut-off value to reject features due to the low importance in the model construction. in the wrapper methods, the performance of a learning algorithm is evaluated to select the optimum subset of features therefore, it is a very computationally expensive process [19] and is best suited for a limited number of features. furthermore, filter methods work well for text mining [19] , and are applicable for odn features, which are essentially nucleotide "words." due to the large number of fingerprint features available (67 in total), we first filtered out the constant and near-constant features (features with < 0.3 standard deviation) also known as zero and near zero variance features using the caret package in r. constant or near constant features take a unique value across samples and are uninformative. this resulted in the removal of 26 features. since these features are binary in nature, we also checked and removed any linear combinations of features if present. this resulted in the removal of 31 features. to understand the distribution in the high and low group of odns we created a cricos plot using the circlize package in r [22] . for all numerical features in addition to removing zero and near zero variance features we also calculated the correlation matrix and filtered out features that were highly correlated. the correlation coefficient was set at 0.85 and features with correlation above the cutoff value were removed. we then normalized the remaining features using centering and scaling techniques to make them unit independent. subsequently, we merged the fingerprint and numerical features to give us a merged set of 40 features, listed in table 3 . in the current study, five ml algorithms, i.e. random forest, gradient boosting machine, shrinkage discriminant analysis, support vector machine and neural network were compared, and the best performing model was chosen for the prediction of novel mtlr9 active odns. to have a non-biased assessment of the performance, kfold cross-validation was followed where one instance of the down-sampled training data was further divided into k partitions. the value of k varies from 5, 10, 15 to 20. for each partition, odns not included in the training were considered part of the testing dataset. finally, the testing data of the instance was used to evaluate the classification accuracy of the model, with the best model selected for prediction on an independent validation dataset. a graphic representation of the general procedure is given in fig. 6 . the random forest (rf) algorithm was introduced by breiman in 2001 [23] and is one of the most powerful ensemble machine learning technique that make predictions by averaging over several independent base learners in order to identify the class label for unknown instances. the base learners are usually the classification and regression trees (cart) constructed using a sample with replacement from the training data with the [23, 24] . briefly rf takes advantage of two powerful statistical techniques, bagging and random feature selection. in bagging each tree is trained on a bootstrap sample (sampling with replacement) and the predictions are made by the majority vote of the trees. furthermore, in rf instead of using all the features, rf randomly selects a set of features to split at each node when growing a tree. to assess the performance of the rf algorithm, rf performs a type of crossvalidation using the out-of-bag (oob) samples (samples which are not included in the training set). the concept of variable importance is inbuilt in the rf algorithm and the importance is measured by the gini impurity criterion index [25] . we used the caret package in r to evaluate the performance and developed an ensemble of 20 different rf models for final prediction. the mtry parameter was tuned using the tunegrid argument in the train function. the accuracy of the five ml algorithms was measured by presenting the prediction results in the form of a confusion matrix and the variety of performance measures were calculated based on the following statistical measures: tp, true positivesthe total number of correctly classified high activity odns. tn, true negativesthe total number of correctly classified low activity odns. fp, false positivesthe total number of low activity odns incorrectly classified as high activity odns. fn, false negativesthe total number of high activity odns incorrectly classified as low activity odns. using the measures above, a series of statistical metrics were computed including sensitivity (se), specificity (sp), balanced accuracy (ba), matthews correlation coefficient (mcc) and precision. the recall rate for the members of the positive class (high activity odns) is given by sensitivity, in eq. (4): similarly, the recall rate for the members of the negative class (low activity odns) is given by specificity, in eq. (5): the balanced accuracy of the model was calculated based on the eq. (6): we then calculated the mcc from eq. (7); the coefficient returns a value between + 1 and − 1. the higher the value of the coefficient, the better the classification result. finally, the precision was computed to measure the reproducibility of the results, in eq. (8): mouse raw-blue tlr9 reporter cell assay raw-blue™ cells are derived from the murine raw 264.7 macrophage cell line with chromosomal integration of a secreted embryonic alkaline phosphatase (seap) reporter construct inducible by nf-κb and ap-1 and were acquired from invivogen. the presence of agonists of mouse tlr9 activates downstream signaling pathways leading to the activation of nf-κb and ap-1, and the subsequent secretion by the raw cells of seap. levels of seap in the culture supernatant are measured chromatographically using the detection medium quanti-blue™. raw-blue cells were cultured in dmem supplemented with 10% (v/v) heat-inactivated fetal bovine serum, penicillin-streptomycin 10,000 u/ml (gibco), and normocin 100 μg/ml (invivogen). subsequently, raw-blue cells were seeded at a density of approximately 1 × 105 cells/well in a volume of 180 μl/well in a flat-bottom 96well culture plate (greiner-one). odns were diluted in saline and added to the culture plate containing raw-blue cells to the total volume of 200 μl. after culturing the cells for 3 h, the levels of seap were determined in the supernatant with quanti-blue™ solution (invivo-gen) by reading the absorbance at wavelength of 650 nm. toll-like receptors: activation, signalling and transcriptional modulation the structural biology of toll-like receptors in silico approach to screen compounds active against parasitic nematodes of major socio-economic importance graphical representation and similarity analysis of dna sequences based on trigonometric functions discovering highly selective and diverse ppar-delta agonists by ligand based machine learning and structural modeling computational methods in drug discovery use of machine learning approaches for novel drug discovery balancing inflammation: computational design of small-molecule toll-like receptor modulators computational discovery and experimental confirmation of tlr9 receptor antagonist leads toll-like receptor 9 interaction with cpg odn--an in silico analysis approach vaccineda: prediction, design and genome-wide screening of oligodeoxynucleotide-based vaccine adjuvants applying machine learning techniques for adme-tox prediction: a review deeptox: toxicity prediction using deep learning the curse of dimensionality in data mining and time series prediction the problem of overfitting 2d-dynamic representation of dna sequences coronavirus phylogeny based on triplets of nucleic acids bases graphical representation and numerical characterization of h5n1 avian flu neuraminidase gene sequence a review of feature selection methods with applications a review of feature selection and feature extraction methods applied on microarray data a review of variable selection methods in partial least squares regression circlize implements and enhances circular visualization in r random forests random forests: from early developments to recent advancements the origins of the gini index: extracts from variabilità e mutabilità (1912) by corrado gini publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations this article has been published as part of bmc molecular and cell biology, volume 20 supplement 2, 2019: 18th international conference on bioinformatics. the full contents of the supplement are available at https:// bmcmolcellbiol.biomedcentral.com/articles/supplements/volume-20supplement-2. supplementary information accompanies this paper at https://doi.org/10. 1186/s12860-019-0241-0.additional file 1. sequence motifs in mtlr9 active odns having an absolute difference in the occurrences above 10% in high and low activity groups of odns, arranged in a clockwise manner. the width of the ribbon shows the average percentage composition of the motifs each group.additional file 2. the effect of odn motif occurrences on the median mtlr9 activity in the low activity group. the median raw-blue activity for all the odns in the low activity group was 0.18. increase or decrease in the median activity values due to the presence of a motif are coloured green and red, respectively, with statistically significant values in bold. the significance threshold was set at p-value < 0.05. the motifs are arranged in alphabetical order.additional file 3. the effect of odn motif occurrences on the median mtlr9 activity in the high activity group. the median raw-blue activity for all the odns in the high activity group was 0.53. increase or decrease in the median activity values due to the presence of a motif are coloured in green and red, respectively, with statistically significant values in bold. the significance threshold was set at p value < 0.05. the motifs are arranged in alphabetical order.additional file 4. results of five-fold cross-validation.additional file 5. results of ten-fold cross-validation.additional file 6. results of fifteen-fold cross-validation. additional file 8. odns used as test and training sets for building the prediction model, along with activity information.authors' contributions vk and np designed the research; vk, ll and jf performed the research; vk, ll, jf. np, and sr analyzed data; vk, ll, np, and sr wrote the paper. all authors have read and approved the final manuscript. this work was supported by funding by the national institute of allergy and infectious diseases of the national institutes of health under contract hhs-n272201400053c. the content is solely the responsibility of the authors and does not necessarily represent the official views of the nih. all data reported in this study are available as tables and supplementary data. the cell line used in the assay is commercially available from invivogen inc. [26] .ethics approval and consent to participate not applicable. not applicable. the authors declare that they have no competing interests. key: cord-022955-vy0qgtll authors: nan title: proteases date: 2005-06-20 journal: febs j doi: 10.1111/j.1742-4658.2005.4739_4.x sha: doc_id: 22955 cord_uid: vy0qgtll nan the incretin hormones glp-1 and gip are released from the gut during meals, and serve as enhancers of glucose stimulated insu-lin release from the beta cells. furthermore, glp-1 also stimulates beta cell growth and insulin biosynthesis, inhibits glucagon secretion, reduces free fatty acids and delays gastric emptying. glp-1 has therefore been suggested as a potentially new treatment for type 2 diabetes. however, glp-1 is very rapidly degraded in the bloodstream by the enzyme dipeptidyl peptidase iv (dpp-iv; ec 3.4.14.5). a very promising approach to harvest the beneficial effect of glp-1 in the treatment of diabetes is to inhibit the dpp-iv enzyme, thereby enhancing the levels of endogenously intact circulating glp-1. the three dimensional structure of human dpp-iv in complex with various inhibitors creates a better understanding of the specificity and selectivity of this enzyme and allows for further exploration and design of new therapeutic inhibitors. the majority of the currently known dpp-iv inhibitors consist of an alpha amino acid pyrrolidine core, to which substituents have been added to optimize affinity, potency, enzyme selectivity, oral bioavailability, and duration of action. various compound series and their sar relative to alpha amino acids will be presented. memapsin 2 (b-secretase, bace1) is the membrane-anchored aspartic protease that initiates the cleavage of b-amyloid precursor protein (app) leading to the production of amyloid-b (ab), a major factor in the pathogenesis of alzheimer's disease (ad). since memapsin 2 is a major target for the development of inhibitor drugs for the treatment of ad, its structure and physiological functions are topics of intense research interest currently. here we discuss the structural features of memapsin 2 and how do they contribute to the activity and inhibition of the protease. structural and kinetic evidence support the presence of 11 subsites for substrate or inhibitor binding in the activesite cleft of memapsin 2. subsites p3 to p2' are most useful in the design of transition-state analogue inhibitors. recent data indicated that subsites p7, p6 and p5 have strong influence of hydrolytic rate or inhibition potency. these subsites are, however, too far from the transition-state isostere for the design of drug-like transition-state inhibitors but can be utilized for the design of non-transition-state inhibitors that compete for substrate binding. besides carrying out proteolytic activity, the ectodomain of memapsin 2 also interacts with app leading to the endocytosis of both proteins into the endosomes where app is hydrolyzed by memapsin 2 to produce ab. a phosphorylated motif in the cytosolic domain of memapsin 2 is responsible for the recognition of gga proteins as part of the recycling mechanism that transports memapsin 2 from endosomes to trans-golgi then back to cell surface. these interactions may also be considered for the design of small-molecular compounds that interfere with memapsin 2 trafficking and thus reduce the production of ab. identification of human carnosinase -a brainspecific metalloprotease m. teufel biochemistry, exploratory research, sanofi aventis, strasbourg, france. e-mail: michael.teufel@sanofi-synthelabo.com metalloproteases form a large and diverse family of proteases and are molecular targets that represent an opportunity for therapeutic intervention. in particular, the development of potent inhibitors has made progress for the family of matrix metalloproteases (mmp). the sequencing of the human genome revealed that a significant percentage of the drugable genome is represented by proteases, many of them still with unknown function. in this presentation, data will be presented on the deorphanization of two previously unknown genes by means of bioinformatics and classical biochemistry. this work led to the identification of human carnosinase, a dipeptidase specifically expressed in the human brain and an ubiquitously expressed close homologue, characterized to be a non-specific dipeptidase. stimulating serpins with synthetic tailor-made oligosaccharides: a new generation of antithrombotics m. petitou thrombosis & angiogenesis, sanofi-aventis, toulouse, france. e-mail: maurice.petitou@sanofi-aventis.com we will discuss our research on synthetic oligosaccharides able to selectively activate the inhibitory activity of antithrombin towards various serine proteinases. we first synthesized pentasaccharides closely related to the antithrombin binding domain of heparin [1] (the active site), as well as analogues displaying different pharmacokinetic profiles. selective inhibitors of coagulation factor xa were thus obtained that represent a new class of antithrombotic [2] drugs currently being evaluated worldwide. we then designed larger oligosaccharides [3] that inhibit both factor xa and thrombin in the presence of antithrombin. they are devoid of undesired nonspecific interactions with blood proteins, particularly with platelet factor 4. clinical trials are ongoing to prove the therapeutic benefits of this new type of coagulation inhibitors. slow tight binding inhibitors in drug discovery: in the case of dppiv and elastase inhibitors z. kapui, e. boronkay, i. bata, m. varga, e. mikus, k. urban-szabo, s. ba´tori and p. ara´nyi discovery research, chinoin member of sanofi-aventis group, budapest, hungary. e-mail: zoltan.kapui@sanofi-aventis.com enzyme are extremely potent causing significant inhibition at very low concentrations that may be comparable to the concentration of the target enzyme. when this inhibition is studied in vitro, complexities arise because the concentration of the inhibitor is so low that it is altered significantly as a result of combination with the enzyme. this situation is referred to as tight-binding inhibition. partly as a result of their low concentrations, tight-binding inhibitors often show slow-binding characteristics. unlike conventional inhibitors that act almost instantaneously (or at least within the ms time scale), slow-binding inhibitors may take several seconds, minutes or even hours for their effect to be fully exhibited. this association between slow-binding and tight-binding is relatively common and slow tight-binding inhibitors are extremely potent and specific. proteolytic enzymes are involved in a multitude of important physiological processes. their intrinsic properties and activities are in the focus of wide-ranging research and they have a valuable role in experimental and therapeutic purposes. serine proteases are attractive targets for the design of enzyme inhibitors since they are involved in the etiology of several diseases. within the class of serine proteases, human leukocyte elastase (hle) is one of the most destructive enzymes in the body. the enzyme dipeptidyl peptidase iv (dppiv) is a serine exopeptidase that cleaves xaa-pro dipeptides from the n-terminus of oligo-and polypeptides. inhibitors of dpp iv are of increasing interest to pharmaceutical industry alike, as they may become established as the next member of the oral antidiabetic class of therapeutic agents. objective of our work was to develop reversible, slow, tight-binding inhibitors against these serine proteases. ssr69071 is a potent inhibitor of hle, the inhibition constant (k i ) and the constant for inactivation process (k on ) being 0.0168 ± 0.0014 nm. this inhibitor is reversible, slow, tight-binding inhibitor with k on = 0.183 ± 0.013 10 6 /ms, and k off = 3.11 ± 0.37 10 )6 /s. ssr69071 inhibits the solubilization of elastin by hle with 13 nm of ic50 value. this inhibitor is one of the most effective inhibitor of a serine proteinase yet described. ssr162369 is a potent, competitive and slow tight binding type inhibitor of the human dipeptidyl peptidase-iv enzyme (k i = 2 nm, t½ = 8 h). on the basis of kinetic properties, ssr162369 forms stable enzyme-inhibitor complex. these slow tight-binding inhibitors have unique inhibitory properties, they are extremely active, and selective, form stable enzyme-inhibitor complex, therefore they have long-lasting effect. their oral activity and long lasting in vivo biological potency agreed very well with stable enzyme-inhibitor complex. the advantages in drug discovery of slow tight-binding inhibitors are discussed in this presentation. enzyme inhibition trend analysis -a new method for drug design m. shokhen, n. khazanov and a. albeck the julius spokojny bioorganic chemistry laboratory, chemistry, bar lan, ramat gan, israel. e-mail: albecka@mail.biu.ac.il many of the drugs that are currently in use or at different stages of development are enzyme inhibitors. therefore, enzyme mechanism-based inhibitors could be developed into highly selective drugs. our novel enzyme inhibition trend analysis method com-bines experimental enzyme kinetics data and high level quantum mechanical modeling of enzyme-inhibitor chemical interactions. the method utilizes the principal catalytic reaction scheme of the target enzyme and does not require its 3d structure (a ligand based approach). the method is valid for the prediction of the trend in binding affinity of inhibitors not only for the specific enzyme for which the qsar model was optimized, but also for the whole enzyme family. the methodology would contribute significantly to overcoming the problem of fast mutational resistance developed by pathogens in response to pharmaceutical treatment. it can be used as a computational tool for expert analysis of various hypotheses about structure-activity relationships formulated for the design of new inhibitors. angiotensin-converting enzyme (ace, ec 3.4.15.1) is a key enzyme for blood pressure control and water-electrolyte homeostasis. a large number of highly potent and specific ace inhibitors are used as oral drugs in the treatment of hypertension and congestive heart failure. somatic ace consists of two homologous domains (n-and c-) within single polypeptide chain, each one containing a catalytic site. the two catalytic sites within somatic ace molecule were long considered to function independently. however, recent investigations indicate the existence of negative cooperativity between ace active sites. we studied the properties of bovine ace active centers by use of separate ace n-domain (n-ace) obtained by limited proteolysis of parent somatic enzyme and testicular ace, which represents c-domain. these results were compared with the data obtained for full-length somatic ace from bovine lungs. the results obtained demonstrate strongly dependent mechanism of action of ace active centers in the reaction of the hydrolysis of tripeptide substrates. however, the hydrolysis of decapeptide angiotensin i proceeds independently on n-and c-domains. the mechanism of inhibition of ace activity is also dependent on the length of the inhibitor: (i) random binding of the ''short'' inhibitor molecule (such as captopril, lisinopril) to one of the active sites dramatically decreases binding of another inhibitor molecule to the second site; (ii) ''long'' nonapeptide teprotid binds to both active sites without any difficulties. since the main physiological ace substrates in the organism are ''long'' peptides angiotensin i and bradykinin, the development of new class of inhibitors with prolonged structure would be beneficial for abolishing of ace activity. synthetic peptide studies on severe acute respiratory syndrome coronavirus (sars-cov) extensive proteolytic processing of the replicase polyproteins, pp1a (486 kda) and pp1ab (790 kda), by the sars-cov 3clike protease (3cl pro ). besides, the structural spike protein of sars-cov contains two heptad repeat regions (hr1 and hr2) that form coiled-coil structures, which play an important role in mediating the membrane fusion process. in this study, we focused on both 3cl pro and the hr regions of sars. previous studies demonstrated that the coronavirus 3cl pro cleaves the replicase polyproteins at no <11 conserved cleavage sites, preferentially at the lq sequence. the reported crystal structure of sars-cov 3cl pro provides insights into the rational design of anti-sars drugs. in order to understand the molecular basis of the enzyme-substrate binding mechanism, we employ the synthetic peptide and mass spectrometry-based approaches to investigate the significance of selected amino acid residues that are flanking both sides of the sars-cov 3cl pro cleavage site. in addition, previous studies indicated that the relatively deep hydrophobic coiled coil grooves on the surface of sars-cov spike protein heptad repeat regions (hr1 and hr2) may be a good target site for the design of viral fusion inhibitors. we have designed and synthesized five truncated peptide analogs derived from hr1 and hr2 peptides based on both bioinformatics and structural analysis. the biological activities of these truncated analogs will be studied using circular dichroism spectroscopy, multidimensional chromatography, protein cross-linking and mass spectrometry-based approach. the above investigation will definitely broaden our knowledge on the sars research and will reveal the feasibility of rational design of synthetic peptide-based drug in combating with sars disease. ras-transfection-associated invasion: involvement of matrix metalloproteinase(s) confirmed using a chicken embryo model and real time pcr during metastasis tumorogenic cells leave the primary tumour and intravasate into the blood/lymphatic system, exiting at a secondary site to establish a secondary tumour. ras-transfection of a parental, non-invasive mcf-10a cell line, established from a patient suffering with benign fibrocystic disease, gave rise to an invasive derivative cell line (mcf-10a-neot) exhibiting the phenotype of a pre-malignant, invasive tumour. invasion and metastasis are protease-assisted processes, proteases either being secreted by the tumour, or by the stromal cells under the influence of the tumour. here we demonstrate the involvement of matrix metalloproteinase(s) in the invasion of the ras-transfected mcf-10a cell line. tumour cells were inoculated onto the damaged surface of the upper chorioamniotic membrane (cam) of a vasculated 9-day old chick embryo. the tumour cells were allowed to invade, and the number of invading cells quantified using real time pcr. inhibitors specific for various proteases were applied to the upper cam, to block invasion, and hence identify the proteinases involved. the number of tumour cells invading into the vascular system was established by sampling the lower cam and quantifying the numbers of alu sequences (present only in human cells) in the dna, isolated from the embryonic tissue, using real-time pcr. using this method, the key role of an mmp was demonstrated. spectrum ptk inhibitor, genistein (100 lm) abolished the release of neutrophil mmp-9, in the presence and absence of extracellular calcium, and reduced the release of timp-1. both pp2 (10 lm), a src family ptk inhibitor, and piceatannol (30 lg/ml), a syk family ptk inhibitor, reduced mmp-9 release substantially, indicating that multiple ptk families might be involved in mmp-9 release. inhibition of either syk or src ptks by piceatannol or pp2 did not appear to influence timp-1 release. low levels of wortmannin (100 nm, inhibition of pi3k) abolished the release of mmp-9 in the absence of calcium, and reduced mmp-9 release in the presence of calcium. investigations into the signaling pathways involved in timp-1 release are continuing. we conclude that mmp-9 release induced by extracellular calcium may be mediated through pi3k and multiple tyrosine kinases, including src and syk family ptks. timp-1 granule release may also be mediated by tyrosine kinases, although src and syk family ptks do not appear to be involved. thermodynamical and structural analysis of cruzain/cruzipain2 complexed with e-64 by molecular modeling and dynamics simulations peptidases represent one of the most relevant enzyme classes targeted by therapeutic intervention. to contribute to the assignment of a physiological role to genomic-derived peptidases and to make them more accessible for the drug discovery process, we have undertaken a program consisting of mrna expression profiling, full-length recombinant expression in insect cells, purification and determination of the catalytic activity for the human proteolytic enzymes. a milestone in the process was the construction of a non-redundant comprehensive database for all human peptidases comprising 443 unique annotated entries, by assembling and filtering public domain information and in-house generated data. in order to get an informative picture on their expression profiling, a transcriptome database for 375 human peptidases was created using the microarray (affymetrix tm ) and taqman ò (applied biosystems) technologies. in parallel, we have set up the procedure for pcr amplification and cloning of the peptidase genes in 96 mtp format and we have already created a repository of 231 full-length human cdnas encoding for peptidases. besides, the conditions for miniaturized insect cell cultures have been established. experimental trials have defined a validated, reliable and fully-automated robotic procedure for the purification of recombinantly expressed peptidases in 96 mtp format. in a pilot study using the high-throughput approach, 85% of the chosen reference hydrolases (14) were secreted into the insect cell medium. of them, 66% have been proven to be catalytically active using fluorescent homogeneous assays in 384well format compatible with the high-throughput screening criteria. the application of this procedure to genomic-predicted peptidases is discussed. comparison of putative glutamate racemases from bacillus species glutamate racemase catalyzes the interconversion between l-and d-glutamic acid and is the cell's source of d-glutamate, a key component in the synthesis of both the bacterial cell wall and the glutamyl capsule. bacillus subtilis has two glutamate racemases in its genome, race and yrpc, while b. cerus and b. anthracis have two race genes, race1 and race1. interestingly, race in b. subtilis is the isoform that is essential and has the greater catalytic efficiency, but both race1 and race2 have higher sequence homology to race, 70 and 79% respectively and share less homology with the yrpc isoform, both at 53%. we have cloned, overexpressed, purified, and are characterizing the kinetic and biophysical properties of the two putative glutamate racemases, race1 and race2 from b. cereus and b. anthracis, and will utilize kinetic and biophysical information to design inhibitors that may result in a novel antibiotic. although these two isoforms share a high sequence similarity, their properties are unique. kinetic data indicates a fivefold difference in catalytic efficiency of race2 compared to that of race1 in the l-to d-glutamate reaction. also, the absence or presence of substrate has an effect on the oligomerization state, details of which will be reported. finally, our collaborators have demonstrated through genetic knock out experiments that only one of the race isoforms is essential for the growth of b. anthracis. we have crystallized the race2 isozyme and x-ray data have been collected to 2.3 å . we are currently solving the structure via heavy-atom derivatives. acknowledgment: this research was funded by nih grant u19 ai056575. anti-inflammatory effects of methionine aminopeptidase 2 inhibition on human b lymphocytes e. janas 1 , r. priest 1 , s. ratcliffe 2 and r. malhotra 1 1 rheumatoid arthritis biology, glaxosmithkline, stevenage, uk, 2 high throughput chemistry, glaxosmithkline, stevenage, uk. e-mail: eva.x.janas@gsk.com processing of n-terminal methionine is an essential post-translational modification in both prokaryotes and eukaryotes regulating the subcellular localization, stability and degradation of proteins. the cleavage of the initiator methionine is catalysed by a highly conserved family of metalloproteases, methionine-aminopeptidase 1 and 2 (met-ap2). human met-ap2 is the molecular target of fumagillin, a natural product with antiangiogenic properties, which covalently binds to his 231 in the catalytic site of met-ap2. although fumagillin has been observed to inhibit proliferation and to cause cell cycle arrest in endothelial cells, the mechanism of inhibition is still poorly understood. recent studies describe high expression of met-ap2 in germinal centre b lymphocytes. here, we investigate the effect of the met-ap2 inhibitor fumagillin on b lymphocyte proliferation and cell cycle progression and compare these results to those observed in hu-vec. in addition our work sheds light on the mechanistic aspects of met-ap2 inhibition by fumagillin and its derivatives. effect of distal mutations on the molecular dynamics of the hiv-1 protease l10i and l90m are the most common distal mutations found in the protease gene of the drug resistant hiv-1 strains. these mutations do not confer resistance by themselves, however induce a large synergy effect when added to active site mutations. understanding the impact of the l90m and l10i mutations on the hiv-1 protease resistance profile is still a challenge. assuming that their contribution to the resistance profile could be mediated by conformational dynamics we have modeled l10i, l90m and l10i/l90m mutants of hiv-1 protease. these unbound mutated and wild type proteases were subjected to 10ns molecular dynamics simulations and compared using an essential dynamics (ed) analysis protocol. the first eigenvector of the native protease describes the flap openning motion. following eigenvectors describe ''the catalytic assisting motions'' (cam) of the protease that becomes dominant upon complex formation with a substrate (piana s et al. j mol biol 2002; 319(2): 567-583). mutation of luecine to methionine residue at position 90 perturbs the protein packing at the dimerization domain. such perturbations affect the dimerization domain motions which correlate with flap opening and the cam. as result the first eigenvector corresponds to the rotational of the one subunit relative to another along axis connecting residues 60 and 60'. in other words l90m mutation mistunes essential motions of the enzyme while retaining its flexibility. this could be the cause of the reduced structural stability of the l90m mutant. in contrast, l10i mutation causes only redistribution of the correlated motions amplitude. the catalytic assisting motion becomes the most influential that results in stabilization of the closed conformation. in turn, the flap opening motions are reduced in l10i mutant. essential dynamics of the double mutant l10i/l90m could be described in the following terms. a strong propagation of the cam induced by l10i mutation is coupled with the altered conformational space caused by l90m mutation. as result the double mutant prefers cam motions that are close to the native protease but also account for the perturbed packing within the dimerization domain. results presented may help understanding hiv-1 protease resistance pathways and in developing more efficient inhibitors of known drug resistant mutants. glutamate carboxypeptidase ii as a cancer marker and therapeutical target: two faces of an enzyme glutamate carboxypeptidase ii is a membrane-bound metallopeptidase expressed in a number of tissues such as jejunum, kidney, prostate and brain. the brain form of gcpii (also known as naaladase) is expressed in astrocytes and cleaves n-acetylaspartyl glutamate, an abundant neurotransmitter, to yield free glutamate. gcpii thus represents an important target for the treatment of neuronal damage caused by excess glutamate. animal model experiments suggest that specific inhibitors of gcpii could be useful for the treatment of several neuropathic conditions, such as brain stroke, chronic neuropathic pain or amyotrophic lateral sclerosis. in the same time, the enzyme is known as prostate-specific membrane antigen since it is upregulated in prostate cancer. it is used for the diagnosis and experimental therapy of prostate cancer using monoclonal antibodies and specific inhibitors. in order to analyze this important pharmaceutical target, we established an expression system based on drosophila schneider's cells. we have also cloned, expressed and characterized its human homolog gcpiii and homologous carboxypeptidases from pig and rat. using specific monoclonal antibodies, we have been able to study the expression of gcpii in various healthy and malignant tissues. we analyzed the substrate specificity of the enzyme using peptide libraries and identified two novel peptide substrates. availability of a recombinant protein enabled to introduce a simple fluorescent activity assay and test specific inhibitors. furthermore, we have biochemically characterized the recombinant protein in terms of pharmacologic properties, oligomeric status, ph dependence and activity modulation by metal ions. we have shown that the glycosylation is indispensable for gcpii carboxypeptidase activity and analyzed the role of each specific n-glycosylation site for the gcpii activity and folding. using site-directed mutagenesis, we are able to identify the domains sufficient and necessary for gcpii activity and also suggest structural explanation for the substrate specificity of the enzyme. dozens of chemicals feature inhibition of proteolytically important tyrosine residue of 20s proteasome by forming covalent bond to hydroxyl group that abolished its catalytic function. in contrary, the approach we utilize here is based on hydrogen and hydrophobic interactions reversibly inactivating all three sites of 20s complexes. we performed flexible docking studies of analogues of a natural product tmc-95a using 1jd2 crystal structure to describe the active site of protein and the position of the ligand. the search yielded several amide-like derivatives that have been screened for superimposition with tmc-95a. few of them revealed similar orientation of propylene groups to the active site of 20s. second screen was performed to reveal the chemicals with the strongest hydrogen-bonding of the ligand to the protein backbone of the receptor. this screen resulted in two chemicals that had strong h-contacts with tyr21, ser129 and, importantly, with proteolytically active tyr1 residue. to access the validity of the predicted chemicals we undertook in vitro studies measuring the hydrolyses of fluorogenic substrate by the sds activated 20s proteasome isolated from hela cells. we obtained more than 85% inhibition of 20s proteasome activity upon incubation the above chemicals (0.5 lg/ml) with proteasomes. we then demonstrated the effectiveness of the obtained chemicals to stabilize the level of oncosupressors, including p53 in benign (mcf10a) and highly metastatic (mda231) cell lines. treatment with these compounds greatly restored the level of p53 in cancer cells. finally, we performed proliferation assay and proved that adding of this artificially synthesized chemicals to mda231 cell line significantly reduced the level of proliferation, whereas mcf10a cells treated at similar conditions have not revealed any abnormal reduction of proliferation below control level. thus, we report of a strategy to predict highly suitable proteasome inhibitors that act via inhibition of protease activity and may lead to creation of a new class of drugs for cancer therapy. localization and trafficking of prostate specific membrane antigen (psma) and its variant form psḿ glutamate carboxypeptidase ii, also known as prostate specific membrane antigen (psma), is a transmembrane glycoprotein highly expressed in maligant prostate tissues. it was shown to represent very useful diagnostic marker and also potential therapeutic target for prostate cancer. two forms of the enzyme were identified in the prostate: full-length transmembrane form consisting of 750 amino acids and a truncated form (called psḿ ), believed to represent spliced variant of psma. the cdnas of both forms are identical except for 266-nucleotide region near 5´end of psma that is absent in psḿ . this deleted region codes for signal peptide as well as for intracellular and transmembrane domains. we are able to detect two protein forms in prostate cancer model cells (lncap cells) and we also show that both forms are glycosylated suggesting that this truncated form might originate from the processing of full length transmembrane psma. number of methods including differential centrifugation, pulse-chase experiments, immunochemistry and gfp-fusion protein analysis were used to analyze the origin, cell localization and trafficking of psma and psḿ in the mammalian cells. we have investigated the substrate specificity of the ns2b(h)-ns3pro protease by using internally quenched synthetic peptides representing both natural cleavage sequences and their recombinant chimeras. synthetic peptides incorporating the o-aminobenzoic acid/3-nitro-l-tyrosine fluorescence donor-quencher pair were used to analyze the minimum substrate length requirement, residue preferences and the contribution of prime side residues for enzymatic cleavage by the ns3 protease. a series of peptides derived from the ns3/ns4a cleavage site was designed for the substrate length mapping study. amino acid truncations in the non-prime and prime side region differently affected rates of substrate hydrolysis and binding as shown by their km and kcat values. the optimal substrate identified was a heptapeptide spanning p4-p3'. chimeric substrates with all possible combinations of non-prime and prime side sequences derived from 5 polyprotein cleavage sites (c, 2a/2b, 2b/3, 3/4a and 4b/5) were assayed for reactivity with the ns3 protease. kinetic parameters revealed a strong impact of the non-prime side residues on km, whereas variations in the prime side region had greater effect on kcat. the fluorogenic derivative of tetrabasic peptide rrrr/gtgn (c/ns5) demonstrated the highest affinity, whereas the peptide kkqr/sagm (2b/c) had the highest turnover number. the one with the greatest catalytic efficiency was identified as rrrr/sltl (c/4a). in addition, we have shown that a ser at p1' is the most preferred residue. the discovery of ns3 substrates with maximized reactivity will be useful for inhibitor development in sensitive high-throughput assays. inhibiting the mtor pathway with cci-779 results in decreased production of vascular endothelial growth factor in a head and neck squamous cell cancer cell line c.-a. o. nathan 1,2 , n. amirghahari 1,2 , x. rong 1,2 and y. sun 1,2 1 nathan, otolaryngology, otolaryngology/head and neck surgery, louisiana state university health sciences center, shreveport, la, usa, 2 nathan, cancer center, medicine, feist-weiller cancer center, shreveport, la, usa. e-mail: cnatha@lsuhsc.edu introduction: overexpression of the proto-oncogene eif4e in surgical margins of head and neck squamous cell cancer (hnscc) patients is an independent predictor of recurrence and is associated with increase in vascular endothelial growth factor (vegf) expression. activation of eif4e in margins through the mtor pathway has led us to determine that cci-779 an mtor inhibitor has both in vitro and in vivo growth inhibitory effects in hnscc cell lines. we wanted to determine if these effects were associated with decrease in vegf production. material and methods: a hnscc cell line fadu was treated with 1 and 10 ng/ml of cci-779 (previously established ic50 = 1 ng/ml). elisa was used to determine vegf protein levels in conditioned medium at 30', 1, 2, 4, 6, 24 and 48 h after treatment with the drug and compared to control cells treated with the diluent for each of the time points. results: a significant decrease in vegf production of 70% was noted at 24 h and maintained at 48 h in treated cells when compared to control cells at the same time points. the decrease in vegf levels (39-47%) was noted within 6 h of treatment with the drug. the percent decrease in vegf protein levels was the same for both doses of cci-779. conclusions: overexpression of eif4e in hnscc increases translation of mrnas with long 5'utrs, one of which is an important angiogenic factor vegf. inhibiting the mtor path-way with cci-779 can potentially decrease vegf production. this has future clinical implications for arresting tumor progression in hnscc patients with molecular positive margins identified by cells overexpressing eif4e, also known as minimal residual disease. proteases from cell culture of jacaratia mexicana m. c. oliver-salvador 1 , g. barrera plant proteases are important in food industry and food technology. the latex of jacaratia mexicana, caricaceae, fruits contains a high level of cysteine proteases. in this work was established a cell suspension culture of j. mexicana. callus culture was initiated from stem explants of j. mexicana on medium consisted of ¼-strength and full-strength ms mineral salts (murashige and skoog, 1965), full-strength ms organics and 6 g/l agar supplemented with cytokinins: 6-benzylaminopurine (bap) at 0.5 mg/l and 6-furfurylaminopurine (kinetin) at 0.25 mg/l and various concentrations (0.25, 0.5 and 1.0 mg/l) of auxins: 2,4-dichlorophenoxyacetic acid (2,4-d) 4-amino-3,5,6-trichloropiridin-2-carboxilic acid (picloram) indoleacetic acid (iaa) a-naphthaleneacetic acid (naa). all of the treatments induced callus except for the iaa, ana and without added phytohormones. the best auxin concentration for callus development was determined to be 0.5 mg/l. and the best condition medium for callus development and proteolytic activity of callus was determined to be 0.5 mg/l 2, 4-d + 0.5 mg/l bap. cysteine proteases were produced on callus culture of j. mexicana and liberated in the medium. also in the cell suspension culture these enzymes were secreted. our results support that is possible the synthesis of proteases in vitro culture of j. mexicana. since protease is a primary metabolite, further improvement in enzyme production is possible by increasing the growth rate and yield of cell culture of j. mexicana. and arginine, from peptides and proteins at neutral ph. it is known to play an important role in the control of peptide hormones, growth factor activity at the cell surface, and in the membrane-localized degradation of extracellular proteins. therefore, the present work was carried out to clone and express carboxypeptidase m in pichia pastoris, aiming at developing specific inhibitors and to evaluate the importance of the enzyme in different physiological and pathological processes. for this purpose, the enzyme's cdna was amplified from total placental rna by rt-pcr and cloned in the vector ppic9, which uses the methanol oxidase promoter and drives the expression of high levels of heterologous proteins in pichia pastoris. the results show that the cpm gene, after cloning and transfection, integrated in the yeast genome, which started to produce the active glycosylated protein. the recombinant protein was secreted into the medium and the enzymatic activity was measured with the fluorescent substrate dansyl-ala-arg. the enzyme was purified by a two-step protocol including gel filtration and ionexchange chromatography, resulting in a 1761-fold purified active protein in a concentration of 400 mg/l of fermentation medium. sds-page showed that recombinant cpm migrated as a single band with molecular weight similar to native placental enzyme (62 kda). these results demonstrate for the first time the establishment of a method using pichia pastoris to express human carboxypeptidase m. mutational analysis of active site of glutamate carboxypeptidase ii human glutamate carboxypeptidase ii (gcp ii) is a membrane metallopeptidase expressed predominantly in the nervous system, prostate and small intestine. in the brain, gcp ii catalyzes cleavage of the abundant neuropeptide n-acetyl-l-aspartyl-l-glutamate (naag) to n-acetylaspartate and glutamate. gcp ii is a type ii transmembrane glycoprotein with a short cytoplasmic nterminal region (amino acids 1-18), a transmembrane domain (amino acids 19-43) and a large extracellular domain (amino acids 44-750) where the active site of the enzyme is situated. gcp ii, as a cocatalytic zinc metallopeptidase, has two zn 2+ ions in the active site which are necessary for its enzymatic activity. recently, the crystal structure of gcp ii was determined in our laboratory and amino acids arg210, asn257, lys699 and tyr700 were proposed to bind c-terminal glutamate of naag (mesters et al., manuscript in preparation). in the presented study, we carried out site-directed mutagenesis to assess the influence of these amino acid residues on the activity of gcp ii. in addition, glutamic acid in the position 424 which is proposed to be involved in proton shift during the catalytical hydrolysis of peptide bond, was mutated to alanine. all the mutant proteins were expressed in insect cells, purified to near homogeneity and enzymatically characterized. it was shown that a mutation in any of these positions lead to significantly reduced naag-hydrolyzing activity. the substitution of glu424 almost completely abolished the enzymatic activity, thus suggesting glu424 is crucial for enzymatic activity of gcp ii. kinetic characterizations of mutant proteins and their substrate specificities will be presented in comparison with wild type gcp ii. comparative study of mammalian homologues of human glutamate carboxypeptidase ii glutamate carboxypeptidase ii (gcpii) is a membrane-bound metallopeptidase. in homo sapiens, gcpii was shown to be expressed in various tissues, mostly in the central nervous system, small intestine and prostate. in brain it hydrolyses n-acetylaspartylglutamate (naag), which is the most prevalent peptide neurotransmitter in the mammalian nervous system, to form glutamate and n-acetylaspartate. in small intestine gcpii plays an important role in folate absorption. in prostate its function is still unknown. it was shown that inhibition of gcpii is neuroprotective in many neurodegenerative states. according to current knowledge of this enzyme, its role may also be important in prostate (and possibly other) cancers, where its expression is dramatically changed in comparison with healthy tissue. gcpii is thus becoming an important therapeutic target and diagnostic molecule. in order to analyze structure-activity relationships in related glutamate carboxypeptidases, we set to study the mammalian homologues of human gcpii: gcpii of rattus norvegicus, sus scrofa and mus musculus, which have approximately 90% dna sequence similarity to human gcpii. information on the biochemical properties, expression pattern and structural similarity is crucial e.g. for testing of gcpii inhibitors in animal models. we have cloned and expressed recombinant gcpii of r. norvegicus and s. scrofa in insect cells with the aim to obtain pure recombinant protein sufficient for structural analysis. data on biochemical comparison of rat, pig and human gcpii forms will be presented and interpreted in the light of the gcpii structure. structural analysis of pla protein from y. pestis: docking and molecular dynamics of interactions with mammalian plasminogen systemz e. ruback and p. g. pascutti laborato´rio de modelagem e dinaˆmica molecular, departamento de biofisica, universidade federal do rio de janeiro, rio de janeiro, r.j. brazil. e-mail: eruback@biof.ufrj.br the plasminogen (plg) system is an important mechanism for the cell migration through the tissues in the mammalian organisms. some bacterial agents can activate this system by proteases and lead an uncontrolled degradation of extracellular matrix components (mec), and make an invasive character of these infections. the y. pestis protein pla is a plasmid coded outer membrane protein, with aspartic-protease activity and is closely related with the proteolytic activation of plg in the serine-protease form called plasmin. exactly how the pla activate plg in plasmin remains unclear. we performed in this work the predicted interaction between the plg and pla protein by rigid-body docking with hex and evaluate the complex stability by molecular dynamics (md) using the gromacs. to evaluate the docking accuracy we use the crystal structure of complex plg-streptokinase. the md results show more stability in the docked plg-streptokinase complex than in crystal complex observed by the rmsd and rmsf calculations after 2 ns in simulation box. the pla model was constructed with spdb-viewer using the pdb structure of ompt as template and quality of model was evaluated with prochek. the docked complex of plg-pla show same interaction site predicted in mutagenesis studies. after 8 ns md (72 083 atoms in box), we observed the relax of beta barrel structure of pla and the progressive approximation and stabilization between the cleavage site of plg into the extracellular loops of pla, followed of the increase of hydrogen bonds number. in this study we report the possible aminoacids that can be participant in the active site and the sub sites of interaction. the total understanding of these interactions can be a important tool for drug design against bacterial proteases. glutamate carboxypeptidase ii (gcpii), also known as naa-ladase i, folylpolyglutamate hydrolase (folh) or prostate specific membrane antigen (psma) is localized in number of tissues. in brain astrocytes, it regulates neurotransmission by cleaving neurotransmitter n-acetylaspatylglutamate (naag) into n-acetylaspartate and most common excitatory neurotransmitter glutamate. inhibition of gcpii activity protects against cell death after brain stroke. in animal models it has been also shown that specific inhibitors of gcpii could be useful for the treatment of chronic neuropathic pain, amyotrophic lateral sclerosis and other pathologic situations when excess glutamate is neurotoxic. gcpii is identical to prostate-specific membrane antigen (psma), a tumor marker in prostate cancer. gcpii is also found in the membrane brush border of the small intestine where it acts as a folate hydrolase. this reaction expedites intestinal uptake of folate through hydrolysis of folylpoly-gamma-glutamates to monoglutamyl folates. gcpii inhibitors might thus be useful in the imaging and treatment of tumors where folate is required for their growth. therefore it was of interest to investigate whether gcpii might be upregulated in brain tumors as well. in order to analyze this possibility, we took 57 samples from 49 patients with brain tumors treated in faculty hospital motol during 1999-2004 and determined expression and activity of gcpii by western blots and immunohistochemistry using monoclonal and polyclonal antibodies developed against extracellular epitopes of gcpii. moreover, we characterized the enzymatic activity of the enzyme in human samples and correlated the expression of gcpii with the type and grade of the tumor. search for optimal isosteres in beta-secretase peptidic inhibitors alzheimer's disease is a widespread, neurodegenerative, dementia-inducing disorder. it is ascribed to the presence of a lesion in several brain regions, the neuritic plaques, which are extraneuronal accumulations of b-amyloid protein (ab), a 42-aa insoluble peptide that mixed with axons and dendrites of neurons, interrupt the synaptic process and cause neuronal death. the peptide ab is a product derived by proteolitic cleavage from a larger transmembrane cell protein termed amyloid precursor protein, app. two enzymes are involved in this cleavage: b-secretase and a-secretase. the first one cuts app between met671 and asp672 of app to generate the n-terminus of ab in the rate limiting step of the process, while the second one cleaves at various places within a sequence between amino acids 712 and 717 to generate the respective c-terminus. using a combination of molecular modeling techniques, we have designed a set of novel b-secretase peptidic inhibitors with a variety of isosteres starting from the available crystallographic structure of this enzyme bound to the inhibitor om99-2. some of the resulting ligands are predicted to have higher affinity for this enzyme than the starting compound. these inhibitors have been synthesized, their b-secretase affinity tested and cell essays have been performed to determine their ability to preclude the formation of ab peptides in cell cultures. schizophrenia and bipolar affective disorder (bd) are two neuropsychiatric diseases with high social and economic costs. in spite of the prevalence of these diseases, no effective long-term treatments are currently available. the enzyme prolyl oligopeptidase (pop) shows increased activity in both illnesses. this serine protease hydrolyzes peptide hormones and neuropeptides at the carboxyl end of proline residues. because of the relevance of pop as a therapeutic target, many specific inhibitors of this protein have been developed in recent years. the inhibitors ono-1603, jtp-4819 and s-17092-1 are currently in clinical trial phase. s-17092-1 has been administered safely to humans and has been proposed as a potential treatment for cognitive disorders associated with cerebral aging. our aim is to develop new peptide human pop inhibitors. to obtain the human brain pop required for our studies, the cdna corresponding to the enzyme was cloned and subsequently expressed in e. coli. pop activity was monitored by 19f-nmr using a new synthesized pop substrate labeled with 19f. this substrate allowed us to perform the inhibition assay avoiding the interference problems of colorimetric and fluorimetric assays and was suitable for high throughput screening of new pop inhibitors. different strategies were used to find putative human pop inhibitors: in silico screening and solid phase synthesis of candidates and screening with chinese medicinal plants extracts. furthermore, nmr studies were performed with the purified human enzyme by labeling the protein isotopically with 15n and d2o and by selective labeling of the residues methionine and tryptophan with 13c. nmr spectra of the labeled protein were obtained at 800 mhz by applying trosy techniques. nmr will provide structural information to perform structure-based drug design of new pop inhibitors in the future as well as to study the interaction of the candidates with the active site of the enzyme. the crucial regulatory function of the membrane type 1-matrix metalloproteinase (mt1-mmp or mmp-14) in connective tissue metabolism, pericellular proteolysis of extracellular matrix (ecm) components, zymogen activation and angiogenesis was demonstrated with the severe phenotype of the mt1-mmp-deficient mice. this membrane-anchored enzyme is not only essential for normal development of hard tissues, but highly expressed in different human cancers where its level frequently correlates with malignant parameters. in most cases the high level of mrna or elevated level of protein can be predictive for disease development but these parameters only partly reflect the expression and forms of mt1-mmp in pathological conditions. biosynthesis, trafficking, intracellular activation, internalization, protein-protein interactions, and the level of physiological inhibitors (timps) strictly influence the activity of mt1-mmp in cells and tissues. in our experimental system, we followed mt1-mmp processing and shedding and characterized the cell-associated and released forms of the enzyme (jbc 2000; 275: 12080-12089; jbc 2002; 277: 26340-26350 and biochem j 2005; 386: 1-10). we found active and inactive truncated forms of mt1-mmp as a result of treatments or experimentally generated imbalance with timps. we have also developed approaches to identify mt1-mmp forms in tumor tissues. here we present and discuss different strategies to identify mmp-14 in diverse biological samples. because mt1-mmp endows tumor cells with the ability to invade and metastasize, these strategies can provide valuable information on the role and function of this key protease. contribution of calpain to cellular damage in human retinal pigment epithelium cultured with zinc chelator y. tamada 1 , t. nakajima 1 , t. r. shearer 2 and m. azuma 1,2 1 research laboratories, senju pharmaceutical co., ltd., kobe, hyogo japan, 2 departments of integrative biosciences, oregon health & science university, portland, or, usa. e-mail: yoshiyuki-tamada@senju.co.jp purpose: we previously showed involvement of calcium-dependent cysteine proteases (calpains, ec 3.4.22.17) in neural retina degeneration induced by hypoxia and ischemia-reperfusion. aged macular degeneration (amd) is one of the leading causes for loss of vision. amd showed degeneration of neural retina due to dysfunction and degeneration of the retinal pigment epithelium (rpe). rpe performs critical functions in neural retina, such as phagocytosis of shed rod outer segments. the purpose of the present study was to determine the contribution of calpain-induced proteolysis to damage in human rpe. zinc chelator tpen was used to induce cellular damage since zinc deficiency is a suspected risk factor for amd. methods: third-to fifth-passage cells from human rpe were cultured with tpen. leakage of ldh into the medium was measured as a marker of rpe cell damage. activity of calpains was assessed by casein zymography, and proteolysis of calpain substrates was detected by immunoblotting. to confirm calpain-induced proteolysis, calpain in homogenized rpe was also activated by addition of calcium. results: tpen caused ldh to leak into the medium from rpe cells, and calpain inhibitor sja6017 inhibited the leakage. casein zymography and immunoblotting for calpain and a-spectrin showed activation of calpain in rpe cultured with tpen. proteolysis by activated calpain was confirmed by addition of calcium to homogenized rpe. conclusion: these results suggested that activation of calpain contributed to rpe damage induced by tpen in vitro. acknowledgments: dr shearer has substantial financial interest (research contract and consulting fee) in senju pharmaceutical co., ltd., and dr azuma is an employee of senju pharmaceutical co., ltd., a company that may have commercial interest in the results of this research and technology. this potential conflict of interest has been reviewed and managed by the ohsu conflict of interest in research committee. in vivo and molecular risk factors of chloroquine or pyrimethamine-sulfadoxine treatment failure in children with acute uncomplicated falciparum malaria the risk factors associated with chloroquine (cq) or pyrimethamine-sulfadoxine (ps) treatment failure were evaluated in 691 children enrolled prospectively in six antimalarial drug trials between july 1996 and july 2004 in a hyperendemic area of southwestern nigeria. following treatment, 149 (39%) of 389 children given cq and 64 (22%) of 302 children given ps failed treatment by day 7 or 14. in a multiple regression model, four factors were found to be independent risk factors for cq treatment failure at enrolment: age <7 years [adjusted odds ratio (aor) = 0.46, 95% confidence interval (ci) 0.26-0.84, p = 0.01], asexual parasitaemia >100 000/ll (aor = 0.46, 95% ci 0.23-0.93, p = 0.03), presence of gametocytaemia (aor = 0.48, 95% ci 0.26-0.88, p = 0.02) and enrolment after 4 years of commencement of the study, that is, after 2000 (aor = 0.47, 95% ci 0.25-0.77, p = 0.003). following treatment with cq, two factors were independent risk factors for failure of treatment: delay in parasite clearance >3 days (aor = 0.26, 95% ci 0.1-0.7, p = 0.014) and presence of gametocytaemia on day 7 or 14 (aor = 2.5, 95% ci 1.1-6.0, p = 0.03). in those treated with ps, two factors were found to be independent risk factors for ps treatment failure at enrolment: age <1.5 years (aor = 2.9, 95% ci 1.3-6.4, p = 0.009) and presence of fever (aor = 0.3, 95% ci 0.14-0.78, p = 0.01). following treatment with ps, delay in parasite clearance >3 days (aor = 0.39, 95% ci 0.18-0.84, p = 0.016) was an independent risk factor for failure of treatment. the quintuple mutants made up of triple dhfr (asn-108, arg-59 and ile-51) mutant alleles and double dhps (gly-437 and glu-540) mutant alleles were found in isolates obtained from 33% of patients, was significantly associated with ps treatment failure (p = 0.001), while pfcrt and pfmdr-1 mutant genes did not significantly predict cq treatment failure in these patients. these findings may have implications for malaria control efforts in sub-saharan africa where control of the disease depends almost entirely on antimalarial monotherapy. development of high-throughput assay of lethal factor using native substrate m.-y. yoon department of chemistry, hanyang university, seoul, south korea. e-mail: myyoon@hanyang.ac.kr designing of inhibitors for anthrax lethal factor (lf) is currently of interest as an approach for the treatment of anthrax because lf plays major roles in cytotoxicity of target cells. lf is a zincdependent metalloprotease that specifically cleaves the mitogen-activated protein kinase kinase (mapkk) family. current assay system for the screening of lf inhibitor use the optimized synthetic peptide coupled with various kinds of fluorophores, which enables fast, sensitive, and robust assays suited to high-throughput screening. however, lines of evidence suggest that the regions beside the cleavage site are also involved in specificity and proteolytic activity of lf. in the present study, we tried to develop high-throughput assay for lf activity based on native substrate, mek1. the assay system relies on the ecl signal resulting from a specific antibody against the c-terminal region of native substrate. a glutathione-coated multiwell plate was used as a solid support to immobilize the native substrate by its n-terminal gst-moiety. immobilized substrate increases the specificity and sensitivity lf-catalyzed substrate hydrolysis compared to the solution phase assay. this assay system would be expected to discover a wide spectrum of anthrax inhibitor. while significant progress has been made over the past decade in elucidating the structure and enzymatic mechanism of the 20s proteasome, our understanding of its assembly pathway and the role of the propeptides in the maturation process is still substantially incomplete. similarly, the mechanisms involved in the translocation of substrates into the central nanocompartment are only dimly understood at present. we have used the rhodococcus proteasome to dissect the assembly pathway, combining mutagenesis and crystallographic studies. for the thermoplasma proteasome we have established a ''host-guest'' interaction system which allows us to follow the translocation of specific substrates into the interior of the proteasome by electron microscopy, mass spectroscopy and x-ray crystallography. transferring substrates to the 26s proteasome in the fission yeast schizosaccharomyces pombe c. gordon mrc human genetics unit, western general hospital, edinburgh, uk. e-mail: colin.gordon@hgu.mrc.ac.uk the ubiquitin pathway is found in all eukaryotes. in this pathway, target proteins are covalently modified by the addition of ubiquitin, a 76 amino acid protein, to specific lysine residues. the ability of multi-ubiquitin chains to function as a signal to target proteins for degradation by the 26s proteasome is well documented. a key question is how is the multi-ubiquitin chain is recognized as a signal? fission yeast rhp23/rad23 and pus1/ rpn10 represent two families of multi-ubiquitin chain binding proteins that can associate with the proteasome as well as some e3 ubiquitin ligases. they seem to provide a link to shuttle ubiquitinated substrates from the e3 ubiquitin ligases to the 26s proteasome. a detailed characterization of their proteasome binding will be presented along with their potential role in ubiquitin conjugate dynamics. finally data will be presented indicating that an additional substrate presentation pathway exists in fission yeast which is also conserved in higher eukaryotes. non-proteasomal rpn10 raises the threshold for association of a ubiquitin-binding protein with the proteasome the ubiquitin proteasome pathway is responsible for the removal of the vast majority of short-lived proteins in the cell. in order to be degraded, a protein substrate is tagged with polyubiquitin and delivered to the proteasome where it is proteolysed. a slew of shuttle proteins is thought to mediate the delivery of polyubiquitinated substrates, although the mechanism remains elusive. one such family of proteins is comprised of rad23, dsk2 and ddi1, which all bind polyubiquitinated substrates through a ubiquitinassociated domain (uba) as well as the proteasome through their ubiquitin-like domain (ubl). another potential shuttle structurally unrelated to the ubl-uba family is rpn10. rpn10 is found as an integral subunit of the proteasome as well as an in an unincorporated pool. we characterized the interactions of these proteins with individual proteasomal subunits, as well as between themselves. we find unique relationships between the putative shuttle proteins and the proteasome, pointing to functional dissimilarity among them. strikingly, unincorporated rpn10 interferes with binding of dsk2 to the proteasome. thus, we propose that rpn10 might play a negative role in proteolysis through its action on dsk2. proteins modified by multi-ubiquitin chains are usually targeted for degradation by the proteasome. in other cases, ubiquitylation mediates protein sorting or regulates other functions. a striking example for a non-proteolytic role of ubiquitin is the rad6 dna damage bypass at stalled replication forks. key elements of this pathway are two ubiquitin-conjugating enzymes, rad6 and the mms2/ubc13 heterodimer, which are recruited to chromatin by the ring-finger ubiquitin ligases, rad18 and rad5, respectively. moreover, also the sumo-conjugating enzyme ubc9 is affiliated with the pathway and we discovered that proliferating cell nuclear antigen (pcna), a dna-polymerase sliding clamp involved in dna synthesis and repair, is a substrate. pcna is (i) mono-ubiquitylated by rad6/rad18, (ii) modified by lysine (k) 63-linked multi-ubiquitylation, which additionally requires mms2/ubc13/ rad5, and (iii) sumoylated by ubc9. all three modifications affect the same lysine residue of pcna, indicating that they label pcna for alternative functions. indeed, we discovered that monoubiquitylation of pcna promotes an error-prone replication bypass, whereas k63-linked multi ubiquitylation mediates errorfree replication across the lesions. in contrast, sumoylation, which occurs even in the absence of dna damage, prevents recombination between homologs at the replication fork. these findings indicate that mono-ubiquitin, k63-linked multi-ubiquitin chains, and sumo are crucial for decision making at the replication fork. ubiquitin-mediated proteolysis is the primary mechanism in eukaryotes for degrading unwanted and misfolded proteins. through the cascade of e1, e2 and e3 enzymes, ubiquitin monomers are attached sequentially to the target proteins, which are then recognized and degraded by the 26s proteasome. the selection and specific timing of polyubiquitination of the target proteins are conferred by different e3 ubiquitin ligases. the anaphase-promoting complex (apc) is one of the most extensively studied e3 ubiquitin ligases that plays essential role in the cell cycle and specific developmental processes. the core apc is composed of 11-13 subunits. except for apc2 and apc11, relatively little is known about the role of the other apc subunits or the assembly of the complex. two wd40-repeat activator proteins, cdc20 and cdh1 determine stage-specific activation of the core apc as well as selection and binding of the apc substrates. in plants, the apc activators are present in multiple copies. arabidopsis contains 5 cdc20 genes, 3 cdh1-type activators known as ccs52a1, ccs52a2 and ccs52b. our work has been focused on the function of apc activators in the cell cycle and plant development, identification of novel apc substrates and on the assembly of the apc complexes. apc activities, based on the expression profiles of the cdc20 and ccs52 genes, will be presented at organism level. by detailed protein interaction studies in yeast two hybrid system and arabidopsis protoplasts or transgenic plants, we shall demonstrate how the core apc interacts with the activators and substrates, and propose a model for apc assembly. characterization of substrate delivery to the saccharomyces cerevisiae proteasome by quantitative shotgun proteomics the proteasome is the central protein degradation machinery in the eucaryotic cell. in conjunction with the ubiquitin system, it is responsible for constitutive bulk protein turnover as well as the controlled degradation of regulatory proteins. the system is very well characterized, but the mechanism by which poly-ubiquitinated substrates are delivered to the proteasome remains unclear. recently our lab has proposed a number of proteins to be proteasome-based receptors for poly-ubiquitinated substrates in s. cerevisiae (rpn10p, rad23p, dsk2p; verma et al., 2004). others (e.g. richly et al. 2005) have put forward a complex model for the delivery of substrates from the ubiquitinating machinery to the proteasome involving the aaa atpase cdc48p. by analyzing the composition of affinity purified proteasome complexes from s. cerevisiae cells lacking these factors and/or exposed to specific proteasome inhibition, we hope to further elucidate the substrate delivery pathway. ubiquitinated proteins recruited to the proteasome are identified utilizing capillary chromatography in-line to electrospray ion trap mass spectrometry (mudpit; link et al. 1999). using a reference strain grown in minimal medium solely providing heavy nitrogen ( 15 n) as an internal standard, we are able to record even gradual fluctuations in sample composition. differences in the recruitment of substrates to the proteasome in varying mutant backgrounds will shed light on the specificity of proteasome substrate receptors and the topology of the substrate delivery mechanism. oxidative protein damage by reactive oxygen species (ros) produces cross-linking, fragmentation and biochemical modification of the amino acids resulting in biological dysfunctions. quercetin, a widely distributed bioactive plant flavonoid, possesses anti-cancer, antioxidants and free radical scavenging activities, as well as it binds with dna causing dna fragmentation. a little is known about protein oxidative damage and its modifications by antioxidants. therefore, the aim of the present work was to investigate the molecular mechanisms of antioxidant and prooxidant activities of quercetin toward proteins. the antioxidant activities of quercetin, such as superoxide dismutase (sod)-and catalase (cat)-mimetic as well as hydroxyl radical (aeoh) scavenging activities were possessed. bovine serum albumin (bsa) was incubated with different concentrations of quercetin. quercetin has highly sod-and cat-like and hydroxyl radical (aeoh) scavenging activities. its activities are concentration dependent. quercetin fragmentized bsa into specific fragments which they detected by sds/polyacrylamide gel electrophoresis. oxidative protein damage was assessed as tryptophan oxidation, carbonyl, quenone and advanced oxidation protein products (aopp) generation. the increase of protein oxidation products was in concentration dependent manner. the carbonyl and quenone contents and aopp were highly significantly elevated in querce-tin-treated proteins when compared with the control sample. the tryptophan fluorescence was highly decreased in treated protein than in the control sample. the mechanisms of antioxidant and pro-oxidant activities of quercetin have been discussed. these results demonstrate that antioxidant quercetin may potentiate protein damage via oxygen free radical generation, particularly .oh radicals by quercetin. protein stability mediated by a hyaluronanbinding deubiquitinating enzyme is involved in cell viability protein degradation by the ubiquitin system plays a crucial role in numerous cellular signaling pathways. deubiquitination, a reversal of ubiquitination, has been recognized as an important regulatory step in the ubiquitin-dependent degradation pathway. we have identified three novel genes encoding a deubiquitinating enzyme, vdub1, vdub2, and vdub3 (villi deubiquitinating enzyme 1, 2, and 3) from human chorionic villi by rt-pcr. their cdnas are 1,593 bp in length and encode an open-reading frame of 530 amino acids with a molecular weight of approximately 58 kda. expression analysis showed that vdub transcripts are highly expressed in the heart, liver, and pancreas. in addition, they are expressed in various human cancerous cell lines. amino acid sequence analysis revealed that they contain the highly conserved cys, his, and asp domains, which are required for the formation of active site for the deubiquitinating enzymes. in vivo and in vitro deubiquitinating enzyme assays indicated that vdub1, vdub2, and vdub3 have deubiquitinating enzyme activity. here, we show that the overexpression of vdub proteins leads to irregular nuclear morphology and apoptosis, suggesting that these vdubs play an important role in regulating signal transduction involved in cell death. interestingly, the sequence analysis showed that vdub proteins contain the putative hyaluronan/mrna-binding motifs, and cetylpyridinium chloride-precipitation analysis confirmed the association between vdubs and intracellular hyaluronan and rna. chemical cleavage of peptide (amide) bonds usually requires harsh conditions. as a result of side reactions and the lack of specificity, chemical amide bond hydrolysis is not a preferred means of protein digestion. we have discovered selective cleavage of peptide bonds in proteins under milder circumstances than any previously reported chemical method. hydrolysis takes place in aqueous buffers in a ph range of 410, and occurs c-terminal to the proteogenic non-natural amino acid azido-homoalanine (azhal), effected by a staudinger reaction after addition of the mild and biocompatible reagent tris(carboxyethyl)phosphine (tcep). key feature in the suggested reaction mechanism is the unprecedented nucleophilic substitution of the resulting gammaiminophosphorane by the flanking c-terminal backbone amide oxygen atom. after hydrolysis, the new c-terminal peptide is present as a homoserine lactone residue and the n-terminal peptide as its free amine. this new reaction may find application as a very mild and selective bio-orthogonal degradation pathway in biochemistry and biomaterials science. overexpression of proteasome b5 subunit increases amount of assembled proteasome and confers ameliorated response to oxidative stress and higher survival rates the proteasome is the major cellular proteolytic machinery responsible for the degradation of both normal and damaged proteins. proteasomes play a fundamental role in retaining cellular homeostasis. alterations of proteasome function have been recorded in various biological phenomena including aging. we have recently shown that the decrease in proteasome activity in senescent human fibroblasts relates to the down-regulation of btype subunits. in this study we have followed our preliminary observation by developing and further characterizing a number of different human cell lines overexpressing the b subunit. stable overexpression of the b5 subunit in wi38/t and hl60 cells resulted in elevated levels of other b-type subunits and increased levels of all three proteasome activities. immunoprecipitation experiments have shown increased levels of assembled proteasomes in stable clones. analysis by gel filtration has revealed that the recorded higher level of proteasome assembly is directly linked to the efficient integration of ''free''/not integrated b-type subunits identified to accumulate in vector-transfected cells. in support we have also found low pomp levels in b5 transfectants thus revealing an increased rate/level of proteasome assembly in these cells as opposed to vector-transfected cells. functional studies have shown that b5 overexpressing cell lines confer enhanced survival following treatment with various oxidants. moreover we demonstrate that this increased rate of survival is due to higher degradation rates following oxidative stress. finally, as oxidation is considered to be a major factor that contributes to aging and senescence, we have overexpressed the b5 subunit into primary imr90 human fibroblasts and we have observed a delay of senescence by 45 population doublings. in summary, these data demonstrate the phenotypic effects following genetic up-regulation of the proteasome and provide insights towards a better understanding of proteasome regulation. expression levels of the components of the ubiquitin/proteasome pathway in pisum sativum seedlings under anoxia stress change in gene expression: proteins produced under aerobic conditions are no longer synthesized and are replaced by the socalled anaerobic peptides. among those proteins synthesized under o 2 deficiency some enzymes of the glycolytic and fermentative pathways were identified in plants. upon reintroduction of air, the anaerobic mrnas disappear rapidly and the increased levels of those enzymes must return to the basal levels. the ubiquitin/proteasome system is a major pathway of proteolysis in eukaryotic cells and may contribute to controlling the intracellular levels of a variety of short-lived regulatory proteins. in this proteolytic pathway, proteins are covalently conjugated to ubiquitin, which flags them for rapid hydrolysis by the 26s proteasome. long polyubiquitin chains must be formed to target a protein for destruction by the proteasome. in plants, the ubiquitin-mediated proteolytic pathway is implicated in a variety of cellular processes, including stress responses. in this study, 3-dayold pisum sativum seedlings were subjected to: (i) 15 h of anoxia stress; (ii) 2 h of aerobic conditions after 15 h of anoxia stress and (iii) 4 h of aerobic conditions after 15 h of anoxia stress. the levels of free and conjugated ubiquitin were detected by immunoblotting using anti-ubiquitin polyclonal antibodies. the changes in the mrna levels of some components of the ubiquitin/proteasome pathway in the seedlings were determined by relative semiquantitative rt-pcr. the results suggest an involvement of the ubiquitin-mediated proteolytic pathway in the anoxia stress response. b2-012p involvement of the anaphase promoting complex in plant development controlled degradation of short-live proteins via ubiquitindependent proteolysis by the 26s proteasome is a key mechanism in eukaryotes that regulates nearly all fundamental cellular processes including cell cycle. polyubiquitination of the protein substrate is sufficient to target it for degradation by a large atp-dependent multicatalytic protease, the 26s proteasome. the selection and specific timing of ubiquitination of the target proteins are conferred by different e3 ubiquitin ligase. the anaphase promoting complex (apc) is one of the e3 ubiquitin ligases, which by ordered destruction of various cell cycle proteins has fundamental roles in the regulation of mitotic and endoreproduplication cycles. the apc functions also outside the cell cycle. in post-mitotic cells, the cdh1 adaptor protein ensures stage specific activation and substrate selection of the apc. in plants, two classes of the cdh1-type activators have been identified, ccs52a and ccs52b that display differential regulation during the cell cycle and plant development as well as differences in their substrate-specificities. in arabidopsis, transient and complimentary expression profiles of the atccs52a1, atccs52a2 and atccs52b genes indicate apc functions during flower development. to identify apc targets, yeast two hybrid screens were performed in the laboratory. out of about 200 interacting proteins, several proteins were transcription factors including a key a regulator of flowers development. data on the interactions of the ccs52 proteins and transcription factors in arabidopsis protoplasts will be presented as well as a model for the apc regulated pathways. novel effects of ubiquitin system and chaperone proteins on the prion ''life cycle'' in yeast t. a. chernova 1 , k. d. allen 2 , e. p. tennant 2 , k. d. wilkinson 1 and y. o. chernoff 2 1 department of biochemistry, emory university, atlanta, ga, usa, 2 school of biology and institute for bioengineering and bioscience, georgia institute of technology, atlanta, ga, usa. e-mail: tcherno@emory.edu yeast prion [psi + ], the self-propagated aggregated isoform of the translation termination factor sup35, is used as a model system to study neural inclusion disorders. prion aggregates and other neural inclusions in mammals were previously reported to sequester ubiquitin (ub). proteasome inhibitors affected the turnover of mammalian prion proteins. however, a role of ub-dependent proteolysis in the prion ''life cycle'' has not been clearly defined. chaperone proteins, which are also implicated in ub-dependent proteolysis, have been shown to influence the formation and propagation of the prion aggregates. our results uncover the connection between alterations of ub system and chaperone proteins in their effects on the maintenance of yeast prion. we have demonstrated that deletions of genes encoding deubiquitinating enzymes, that are critical for ub regeneration at the proteasome (ubp6) or the vacuole (doa4), cause pleiotropic phenotypic effects that are primarily due to decreased levels of free ub in the yeast cells. these alterations, as well as deletion of the gene encoding ub-conjugating enzyme, ubc4, decreases [psi + ] curing by the overproduced disaggregase hsp104, suggesting that ub system influences hsp104-dependent clearance of prion aggregates. spontaneous [psi + ] formation was also increased in the ubc4 depleted cells. we previously demonstrated that excess of cytosolic chaperone ssa of hsp70 family increases de novo formation of [psi + ]. both in vivo and in vitro experiments uncover direct interactions between sup35 and hsp70 proteins. the amount of sup35-bound to hsp70-ssa was increased in ubc4 deletion strain. we propose a model to explain roles of hsp104, hsp70 and ub system in the prion life cycle. effects of parkinson''s disease mimetics on proteasome activity and protein turnover in human sh-sy5y neuroblastoma cells it has recently been suggested that impairment of the ubiquitin/ proteasomal system contributes to the degeneration of dopaminergic neurons (dn) and lewy body (lb) formation in parkinson's disease (pd). mitochondrial dysfunction is also a key factor in pd and agents such as mpp + and dopamine, which inhibit mitochondrial electron transport, produce selective degeneration of dn in animal models. in this study the effects of treating sh-sy5y cells with mpp + or dopamine over 72 h on proteasomal chymotrypsin-like activity (cla) was monitored. mpp + (0.1mm) caused a sustained depletion of glutathione levels followed by a reduction in proteasomal activity. a reduction in atp levels, caused by higher levels of mpp + (2mm), exacerbated this effect. exposure to low dopamine concentrations (0.1mm) led to large reductions in atp without affecting cla or glutathione levels; whilst higher concentrations (2mm) caused marked reductions in cla, glutathione and atp levels. these results suggest that, under oxidative stress, glutathione levels are important regulators of proteasomal activity in this cell line. our group has shown that mpp + can destabilize the neurofilament network in shsy-5y cells, partly due to changes in phosphorylation of neurofilament (nf) chains. as nfs are important components of lbs, and their mode of turnover is uncertain, we tested the effects of proteasome inhibitors on nf levels. treatment with these inhibitors led to nf accumulation, which was enhanced when glutathione levels were artificially depleted, suggesting that nfs can be degraded via the proteasomal pathway. the effects of proteasome impairment on protein accumulation will be discussed. mitochondria and the hypoxia-inducible factor 1 (hif-1): regulation of hif-1 is independent of a functional mitochondrial respiratory chain k. doege, w. jelkmann and e. metzen insitute of physiology, university of luebeck, luebeck, germany. e-mail: doege@physio.uni-luebeck.de the hypoxia-inducible factor hif-1 is the ''master-regulator'' in adaptation to low oxygen concentration and induces the hypoxic expression of several target genes, e.g. erythropoietin and vascular endothelial growth factor (vegf). in normoxia hif-1a is constantly produced but also degraded by oxygen-dependent prolyl-hydroxylation. mitochondria consume most of the oxygen delivered to cells and have been implicated in oxygen sensing. firstly, mitochondria have been proposed to stabilize hif-1a by production of reactive oxygen species (ros) in hypoxia. secondly, inhibition of the respiratory chain, e.g. by nitric oxide, has been proposed to cause redistribution of intracellular oxygen followed by reactivation of the prolyl hydroxylases and inhibition of hif signalling. we have used cells depleted of mitochondrial dna (q0) and gas permeable cell culture dishes to eliminate all oxygen diffusion gradients affecting the cells. we show that these dishes neutralize all effects of mitochondrial inhibition. additionally, cellular hypoxia as assessed by pimonidazole staining has been evaluated in human osteosarcoma cells treated with inhibitors of the respiratory chain under hypoxia. these results demonstrate an elevated po 2 under hypoxic conditions after treatment with mitochondrial inhibitors correlating with an intracellular oxygen concentration which reduces hif-1 activation. thus, neither the absence of ros nor the redistribution of intracellular oxygen supply leads to the destabilization of hif-1a in hypoxia. our experiments provide evidence that an increased intracellular po 2 evoked by the absence of mitochondrial oxygen consumption reactivates the prolylhydroxylases and is therefore responsible for the degradation of hif-1a under hypoxic conditions. enzyme activity is generally higher in rhizosphere than in bulk soil, as a result of a greater microbial activity sustained by toot exudates or due to the release of enzymes from roots. negative effects of heavy metals on soil microorganisms and enzyme activities have been long recognized. the aim of this study was to assess the stimulatory effects of different low molecular weight organic compounds commonly present in root exudates (mres) on microbial activity and protease activities and , and how high cd concentrations affect such stimulatory effects. soils (arenic udifluvent) were sampled from the agir long-term field trials, contaminated with cd nitrate at rates of 0 (control soil), 20 and 40 mg cd per kg of soil. the mre solutions contained glucose, citric acid, oxalic acid, glutamic acid or a mixture of the four compounds, added to give a rate of 300 mg of mre-c per kg of soil. the effects were measured at 4 mm (bulk soil) distance from the mrs. protease activity was determined by hydrolysis of n-benzoylargininamide (baa). the results showed that different mres had different stimulatory effects on microbial growth and on the protease activities, mostly localized in the rhizosphere soil layer. in the control soil, the dsdna content was significantly increased by the addition of all mre in both rhizosphere and bulk soil layers. the 20 and 40 mg cd per kg of soil negatively affected on protease activity. the glucose, citric acid, oxalic acid, glutamic acid, mres mix in both rhizosphere and bulk soil layers, did not stimulate protease. the, microbial growth and protease activities were drastically reduced by high cd concentrations. participation of different digestive proteinases of the yellow mealworm, tenebrio molitor, in initial stages of hydrolysis of the main dietary protein insects generally have a wide spectrum of digestive proteinases. the knowledge about the impact of different proteinases to initial stages of hydrolysis of dietary proteins is essential for insect control by means of proteinase inhibitors and bacillus thuringiensis toxins. the larvae of a stored grain pest yellow mealworm, tenebrio molitor, were reared on milled oat flakes. the main dietary protein for these larvae was 12s globulin, the main storage protein of oat seeds. to study the initial stages of 12s globulin hydrolysis in vitro the reaction was performed in the physiological conditions of anterior midgut (am) (ph 5.6) by purified enzyme preparations from am: two fractions of cysteine proteinases cys ii and cys iii, chymotrypsin-and trypsin-like proteinases. total hydrolysis of 12s globulin was observed with cys ii. slightly less effective was hydrolysis by chymotrypsin-like enzyme. cys iii cysteine and trypsin-like proteinases produced only partial hydrolysis of seed globulin. in all cases high molecular mass (mm) intermediate products were formed testifying that hydrolysis of 12s globulin was sequential. incubation with both cysteine proteinase fractions led to formation of 31 kda product, while serine proteinases proin contrast to ''classical'' bioregulator peptides, peptides could be generated in the course of catabolic degradation of functional proteins. for 15 years, we have been interested in such particular group of peptides derived from blood hemoglobin, hemorphins. hemorphins consist in a family of opioid receptor-binding peptides from 4 to 10 amino acids that are released by proteolytic processing from the (32-41) segment of human hemoglobin betachain. they are prevalent throughout the peripheral and central nervous system and have been isolated in vivo from tissues or fluids. many in vivo physiological effects have been related (coronaro-constrictory, anti-tumorous, immunoregulatory activities) and several of the hemorphins interact at various levels of the reninangiotensin system (ras) by inhibiting angiotensin-convertingenzyme (ace), aminopeptidase n (apn) and dipeptidyl peptidase iv (dppiv) activities. in addition, some hemorphins and in particular lvv-hemorphin-7 (lvvypwtqrf), binds with high affinity to the brain (ic 50 = 4.15nm) and renal at4 angiotensin receptor subtype and is possible the main endogenous ligand from this receptor. in an attempt to characterize in vivo precise mechanisms for their release, our attention is focused towards tumoral and central nervous system environments. the last one is particularly interesting as all cellular components implicated in the release of hemorphins are present simultaneously: the haemoglobin precursor and localized brain proteases which might come in contact with blood haemoglobin. in this purpose, the examination of potentiality for this tissue to generate ''neuro''-hemorphins would be of interest since sources of hemorphins in the brain have not yet been definitively established. later, we showed that sgt1 interacts with calcyclin (s100a6) and other calcium-binding proteins of the s100 family (nowotny et al. j biol chem 2003). moreover, in collaboration with dr chazin's group, we found that in vitro sgt1 binds to hsp90 (lee y-t et al. j biol chem 2004). in this work we studied the expression and subcellular localization of sgt1 in mammalian cells by means of western and northern blots. among different cell lines examined human embryonic kidney hek293 and human glioma t98g cells exhibit highest expression of sgt1 protein. moreover, we found that in mouse and rat cells there is one isoform of sgt1, while in human cells two isoforms of this protein were found. to study the subcellular localization of sgt1 we chose the cells containing moderate level of sgt1 such as human epidermal hep-2 cells. by applying immunocytochemistry we found that this protein is present not only in the cytoplasm but also in the nucleus. at present we check the effect of intracellular ca 2+ concentration on subcellular localization of sgt1 and on its co-localization with target proteins. acknowledgements: this work was supported by grants: kbn 3 p04a 043 22 and firca/nih r13 tw006005. combining reverse genetics, reverse chemogenomics and proteomics to assess the impact of protein n-terminal methionine excision in the cytosol of higher eukaryotes in living organisms whatever the cell compartment, proteins are always synthesized with methionine (met) as the first residue. however, this first met is specifically removed from most mature proteins. in the course of protein n terminal met excision (nme), the free n terminal met is removed by met aminopeptidase (map) cleavage. three enzymes (map1a, map2a and map2b) have been identified in the cytoplasm of arabidopsis thaliana. by combining reverse genetics and reverse chemogenomics in transgenic plant lines, we have devised specific and reversible switches for the investigation of the role of cytoplasmic nme in a. thaliana and of the respective contributions of the two types of cytoplasmic map throughout development. in the map1a ko context (map1a-1), modulating map2 activity by treatment with various concentrations of the specific drug fumagillin impaired plant development. hence, (i) cytoplasmic nme is essential in plants, (ii) plant map1a and map2s are functionally interchangeable as a complete block of either map type activity does not cause any visible molecular or phenotypic effect, (iii) a minimal level of cytoplasmic map is required for normal development and (iv) the plant a. thaliana appears an excellent system to study nme and the associated-role of anti-cancer agents like fumagillin. proteomics was used to assess the impact of nme blocking induced by fumagillin. we used a wild-type plant and the map1a-1 variant grown in the presence of 100 nm fumagillin. the map1a-1 variant showed a dwarf phenotype. we compared by 2d gel electrophoresis the patterns of each protein extracts. protein spots were identified by tandem mass spectrometry. the data show that fumagillin induces many dedicated pathways, with a prevalence of those related to oxidative stress. prolyl endopeptidases from the midgut of the yellow mealworm tenebrio molitor side of proline residues. these enzymes were found in mammals, several higher plants, fungi and bacteria. it is suggested that the enzymes participate in the in vivo regulation of the action of biologically active peptides. we for the first time report about two prolyl endopeptidases in the larval midgut of a stored product pest yellow mealworm tenebrio molitor where they can participate in the proteolysis of one of the main dietary proteins of t. molitor larvae -rich in proline prolamines. characteristics of two prolyl endopeptidases are significantly different. optimum for hydrolysis of the substrate z-ala-ala-pro-pna (n-carbobenzoxy-l-alanyl-l-alanyl-l-prolyl-p-nitroanilide) by prolyl endopeptidase 1 was at ph 8.5, and prolyl endopeptidase 2 -at ph 5.6. prolyl endopeptidase 1 displayed high phstability in the ph range 7.0-10.0 and the rate of hydrolysis increased in the presence of kcl and cacl 2 . prolyl endopeptidase 2 demonstrated low stability in the whole ph range, the rate of hydrolysis strongly decreased in the presence of above mentioned salts, but increased in the presence of high concentrations of edta. the influence of cell growth media on the stability and antitumour activity of methionine enkephalin studies with cultured tumour cell lines are widely used in vitro to evaluate peptide-induced cytotoxicity as well as molecular and biochemical interactions. the objectives of this study were to investigate the influence of the cell culture medium on peptide metabolic stability and in vitro antitumour activity. the degradation kinetics of the model peptide methionine enkephalin (met-e, tyr-gly-gly-phe-met), demonstrated recently to play an important role in the rate of proliferation of tumour cells in vitro and in vivo, were investigated in cell culture systems containing different amounts of foetal bovine serum (fbs). the influence of enzyme inhibitors (bestatin, captopril, thiorphan) on the met-e degradation was also investigated. the results obtained in the dulbecco's modified eagle medium containing 10% fbs indicated a rapid degradation of met-e (t 1/2 = 2.8 h). pre-incubation of the medium with a mixture of peptidase inhibitors reduced the hydrolysis of met-e, as shown by increased half-life to 10 h. the in vitro activity of met-e against poorly differentiated cells from lymph node metastasis of colon carcinoma (sw620) and human larynx carcinoma (hep-2) cells was determined. tumour cells were grown 3 weeks prior to the experiment in a medium supplemented with 10, 5 or 2% fbs. statistically significant to mild or no suppression of cell proliferation was observed in all cultures. in both cell lines, a significant suppression of cell growth by a combination of peptidase inhibitors and met-e, compared with cells exposed to the peptide alone and cells grown in the absence of met-e, was observed. this study indicated that caution must be exercised in interpreting the antiproliferative effects of peptide compounds in conventional drug-response assays. protein metabolism in whole body and skeletal muscle of laboratory rats treated by proteasome inhibitors proteasome inhibitors are new agents which may be used in treatment of cancer and other severe disorders. one of the possible side effects of their administration is disturbance in protein metabolism which may affect outcome of the illness. two separate studies were performed using wistar rats. in the first study, m. soleus (sol) or m. extensor digitorum longus (edl) were incubated in medium containing 30 mmol/l mg 132 or 30 mmol/l adaahx3l3vs or without inhibitor (control). protein synthesis was evaluated using l-[1-14c]leucine. proteolysis was determined according to the rate of the tyrosine release into the medium during incubation. in the second study, proteasome inhibitor mg 132 diluted in dimethyl sulfoxide (dms) was administered intraperitoneally in dose 10 mg/kg b.w. controls consisted of dms treated animals. changes in protein and amino acid metabolism were estimated in steady-state conditions using continuous infusion of l-[1-14c]leucine 2 h later. mann-whitney (in vivo study) and paired t-test (in vitro study) were used for statistical analysis. in in vitro study, both mg 132 and adaahx3l3vs significantly decreased protein synthesis and proteolysis. however, in in vivo study, a significant increase in whole-body protein synthesis and proteolysis were observed in mg 132 treated animals. acknowledgements: the study was supported by a grant of gacr no. 303/03/1512. bioinformatical evidence for a prokaryotic ubiquitin-like protein modification system h. scheel, s. tomiuk and k. hofmann bioinformatics group, memorec biotec gmbh, ko¨ln, germany. e-mail: kay.hofmann@memorec.com until recently, the ubiquitin system has been considered a purely eukaryotic invention. by now, the bacterial moad/moeb and this/thif systems are known to be prokaryotic versions of a rudimentary activation system for ubiquitin-like proteins. however, similarities to the ubiquitin system end after the activation step, as moad and this are not conjugated onto target proteins but rather have a role in the biosynthesis of molybdopterin and thiamin, respectively. the eukaryotic protein urm1 is the closest homolog of moad and this. unlike its bacterial cousins, urm1 is conjugated onto target proteins and thus can be considered the founding member of the diverse eukaryotic ubiquitin family. by using a bioinformatics approach that integrates methods of sequence analysis, phylogenetics, phylogenomics and gene-order analysis, we were able to show that many bacteria possess a third ubiquitin-like activation system that most likely is used for protein modifications. the novel system uses a moad/this relative, which is more closely related to urm1 than the typical moad and this proteins. these bacterial urm1 (burm1) proteins typically require the proteolytic removal of a c-terminal extension, which masks the gg motif important for activation. many burm1 operons contain a mpn+/jamm domain protein (belonging to a bona fide ubiquitin-specific protease family), which is most likely responsible for this cleavage. as a third component, an e1-like enzyme is also part of typical burm1 operons. the burm1-associated e1 enzymes look more like uba4 (the eukaryotic urm1-e1) than like the bacterial moeb/thif e1 enzymes. interestingly, the mpn+/jamm protease is also conserved in those bacteria whose burm1 end with gg, suggesting that burm1 removal is important not only for the activation step b2-025p non-hypoxic induction of hypoxia-inducible factors by insulin and 2-deoxy-d-glucose hypoxia-inducible factors (hifs) are key mediators of the cellular adaptation to hypoxia, but also respond to non-hypoxic stimuli like insulin. to clarify involvement of all known hif subtypes in conditions resembling diabetes, we determined distribution of mrnas and proteins in rats subjected to in vivo hypoglycemia and glucoprivation. wistar rats were infused with either saline, insulin, or 2-deoxy-d-glucose (2-dg) to provoke hypoglycemia or impaired glucose assimilation. using real-time qpcr, mrna levels of hif subunits 1a, 2a, 3a, 1b, and of the target gene glut-1 were determined in various organs. cellular distributions of hif-a proteins were examined by immunohistochemistry. treatments with insulin or 2-dg resulted in a widespread increase in hif-3a mrna after 6 h, whereas mrna expression of other hif subunits remained unaffected, except for hif-2a which increased in lung and heart after 2-dg. in cerebral cortex and kidney, enhanced staining of all hif-a proteins was observed after insulin or 2-dg treatments. lung, heart and kidney showed enhanced levels of glut-1 mrna. both hypoglycemia and glucoprivation provoke functional activation of the hif system, with transcriptional up-regulation of hif-3a representing a typical response. our data indicate an involvement of the hif system, and hif-3a in particular, in the pathophysiology of diabetes. fragments of human salivary statherin and pb peptide underlying a furin-like pro-protein convertase action in the pre-secretory salivary fragmentation pathway the recent analysis of some derivatives of human salivary peptides and proteins [13], such as acidic and basic proline-rich proteins (prp) and histatins, allowed recognizing in the presecretory salivary fragmentation pathway the action of a furinlike pro-protein convertase of the kexin-subtilisin family, often followed by a carboxy-peptidase action. on the same line, the present study was carried out to search in human saliva the fragments generated from statherin and pb peptide by the action of furin-like proteinases, utilizing a selected-ion monitoring strategy based on hplc-it ms. the fragments and post-translational derivatives detected with high frequency in multiple samples were the following: (i) statherin (5380 amu), des-phe-43 (5232 amu), des-thr-42-phe-43 (5131 amu), des-asp-1 (5265 amu), mono-phosphor. (5300 amu), statherin sv2 (missing 6-15 residues; 4149 amu), fragm. 10-43 (4128 amu), fragm. 11-43 (3971 amu), fragm. 14-43 (3645 amu). moreover, the fragm. 6-57 (5215 amu) of pb peptide (5793 amu) was identified. the quantity of these fragments in salivary samples was usually <10% of the parent peptide. the identified fragments confirmed the action of a proprotein convertase on furin-like consensus sequences, being the cleavage at arg-9 (ekflr), arg-10 (lrr) and arg-13 (rrigr) for statherin, and at arg-5 (rgpr) for pb peptide. detection of statherin missing n-and c-terminus residues indicated also a pre-secretory exopeptidase action, already observed in other salivary peptides. the function of these statherin and pb derivatives in the oral cavity must be elucidated. cloning and expression of a pepstatin insensitive acid protease from thermoplasma volcanium in e. coli acid proteases, commonly known as aspartic proteases, are recognized by their specific inhibition by pepstatin. acid proteases are found in microorganisms both as intracellular and extracellular enzymes. there is very limited number of thermostable, pepstatin insensitive acid proteases isolated from bacterial sources. the only example of purified and cloned acid protease from archaebacteria is thermopsin, produced by sulfolobus acidocaldarius. this thermophilic enzyme represents a new class of acid proteases. to extend our knowledge on the microbial acid proteases with thermostable properties, in this study we have undertaken the cloning and expression of a thermostable, pepstatin insensitive acid protease from themoacidophilic archaeon thermoplasma volcanium. a primer set was designed based on nucleotid sequence of the predicted thermopsin gene and pcr amplification produced a 3080 bp fragment, which covered complete thermopsin gene with some upstream and downstream sequences. the amplified thermopsin gene was cloned in e. coli, using pdrive vector. the alignment of the amino acid sequences of thermopsins from various archaea revealed the highest homology (44%) between the tp. volcanium thermopsin and putative tp. acidophilum enzyme, thermopsin 1. there was a low degree of similarity (28%) between the tp. volcanium thermopsin and thermopsin from sulfolobus acidocaldarius. expression of the recombinant thermopsin was attempted using qia expression kit, where the cloned gene was ligated to pqe expression vectors to be expressed under the control of t5 promoter. in this system the protein was tagged with 6xhis residue at n-terminal end so that it could be selectively isolated using ni-nta metal-affinity chromatography. include various vital proteins with discrete functions in the propagation of apoptosis. our aim is to generate a caspase cleavage site predictor specific for each member of the caspase family in order to make subtype-specific predictions of new caspase substrates. we have used a set of experimentally verified proteins to generate sequence logos and train a neural network in order to predict caspase cleavage sites. machine learning techniques, such as artificial neural networks, are often well suited to integrate the subtleties of sequence variations. this approach also enables integration of structural information in the pattern recognition procedure which could possibly increase the predictive performance of the neural network. the identification of new caspase substrates can lead to further elucidation of several cellular processes involving caspases, including apoptosis, cell cycle regulation, cellular differentiation, and pro-inflammatory responses. in addition, the generation of caspase inhibitors could be greatly aided by a caspase cleavage site predictor. regulation of protein synthesis and autophagic-lyososomal protein degradation in isolated pancreatic acini a. l. kovacs and e. papp cell physiology laboratory, department of general zoology, eotvos lorand university, budapest, hungary. e-mail: alkova@cerberus.elte.hu a series of biologically active compounds (wortmannin, ly294002, 3-methyladenine, rapamycin, okadaic acid, theophyllin, insulin, glucagon, cholecystokinin) influencing protein synthesis and autophagic-lysosomal protein degradation by interfering with important signalization pathways were investigated. our results show that in exocrine pancreas cells phosphatidyl inositolkinases (pi3k-s) are activators, while the target of rapamycin protein (tor) is an inhibitor of autophagy. camp is an inhibitor of lysosomal protein degradation that acts through members of the pi3k family. okadaic acid inhibits lyososomal protein degradation without inhibiting the formation of autophagic vacuoles. the inhibition of pi3k-s and tor diminishes protein synthesis, inhibitors of these kinases reduce the synthesis stimulatory effect of insulin. cholecystokinin showed a biphasic stimulatory effect while glucagon was ineffective on protein synthesis. on the base of these results a possible signalization pathway is suggested for autophagic segregation and lysosomal protein degradation in pancreatic acinar cells. purification and characterization of a bifunctional protease from vibrio vulnificus in this study, we purified and characterized an extracellular protease showing dual functions as prothrombin activator and fibrinolytic enzyme from vibrio vulnificus atcc 29307. the purified enzyme had broad substrate specificity towards various bloodclotting associated proteins such as prothrombin, plasminogen, fibrinogen and factor xa. the cleavage of these proteins could be stimulated by addition of 1 mm mn 2+ . the protease could acti-vate prothrombin to active thrombin. however, the thrombin activity generated from prothrombin activation by the protease seemed to be transient, with further cleavage resulting in a loss of activity. interestingly, the enzyme could enhance the activity of thrombin during the initial rate of fibrin formation when purified fibrinogen was used as substrate. it could also actively digest fibrin polymer as well as cross-linked fibrin. these results suggest that the secreted protease functions as a prothrombin activator and a fibrinolytic enzyme to interfere with blood clotting as part of the mechanism associated with its pathogenicity in human. tumor invasion and metastasis are the major causes of treatment failure and death in cancer patients. one requisite for neoplastic cell invasion during tumorigenic processes is the remodeling events that occur within the stroma or extracellular matrix (ecm). cysteine cathepsins, most likely along with matrix metalloproteases and serine proteases, degradate the ecm, thereby facilitating growth and invasion into surrounding tissue and vasculature. clinically, the activity levels and localization of cysteine cathepsins and their endogenous inhibitors have been shown to be of diagnostic and prognostic value. the aim of our study was therefore both the determination of prognostic and diagnostic impact of cathepsins b, l and h from human tissues extracts (normal and tumor tissue) and extracellular fluids (such as plasma and urine) and a1-proteinase inhibitor (pi) in pathogenesis of different types of human brain tumors, and extraction and purification of cysteine cathepsin endogenous inhibitors from normal and tumor brains and studying of their physicochemical properties. it was found that the increasing of cysteine cathepsins b, l, h activity levels in brain tumors tissues depend on histostructure, histogenesis and tumor malignancy grade. increasing of cathepsins l and h activity levels was found in plasma and urine in depending on histogenesis. at the same time decrease in pi activity level was registered. besides, kinetic characteristics of extracted normal brain endogenous inhibitors of cysteine cathepsins were determined. in extracted tumor brain endogenous inhibitors, there were differences in physicochemical properties in comparison with normal. the data obtained contribute to understanding the participation of cysteine cathepsins and their inhibitors in mechanisms of cancer genesis and both become useful for solving the problem of improving of tumor therapy and provide the possibility of using their activity as diagnostic and prognostic markers. protein hydrolysates of sea origin as components for microbiological culture media dry hydrolysate was prepared from protein-containing waste of icelandic scallop chlamys islandicus processing (spw) by means of a proteinase complex from king red crabs hepatopancreas. the enzyme consist of the proteolytic enzyme complex from crab hepatopancreas, in which serine proteases dominate (collagenase, elastase and trypsin-and chymotripsin-like proteinases). as proteinases from king red crab hepatopancreas have high enzymesubstrate affinity to icelandic scallop proteins, a high degree of proteolysis can be achieved. the composition and properties of the material were investigated on enzymatic protein hydrolysate from spw obtained under the most technologically suitable conditions: 50-55 o c, ph 7.5, 6 h, the ratio between the protein material and the enzyme preparation being 1000:6. for comparison we examined the composition of commercial pancreatic hydrolysate from poor-quality fish species, mainly boreogadus and micromestistus. it was found that hydrolysate from spw significantly overpowered the commercial analog in the mass percentage of the target product (free amino acid and oligopeptides). the resulting product contains not <80% free amino acids and oligopeptides. predominant are aspartic acid, leucine, isoleucine, arginine and lysine, which account for >5% of the free amino acids. the potential usage of the protein hydrolysate as a nutrient for microorganism cultivation is estimated. microbiological studies have demonstrated that the hydrolysate from spw can be used as a protein component in nutrient media. the tested microbial strains satisfactorily grew on the media. the z variant alpha-1 proteinase inhibitor (a1piz) misfolds in the endoplasmic reticulum (er) and is a substrate for er-associated protein degradation (erad). we report here that a1piz degradation is also dependent on vps30/atg6, a gene that encodes a component of two pi3-kinase complexes that regulate membrane traffic; complex i is required for autophagy, complex ii is required for the cpy-to-vacuole pathway. to elucidate why vps30p participates in a1piz degradation, we tested the hypothesis that erad was saturated at elevated levels of a1piz expression and that excess a1piz was targeted to one of these alternative quality control pathways. overexpression of a1piz led to vacuole-dependent degradation and both complexes were required for delivery of the excess a1piz to the vacuole. when the cpy-to-vacuole pathway was compromised a1piz was secreted and the distribution of soluble vs. aggregated forms of a1piz was comparable with that of wild type yeast. however, disruption of autophagy led to an increase in levels of aggregated a1piz; suggesting that when erad is saturated the excess a1piz is selectively targeted to the vacuole via the cpy-to-vacuole sorting pathway, while excess a1piz that forms aggregates in the er is targeted to the vacuole via autophagy. together, these results reveal multiple pathways for recognition and removal of aberrant proteins and provide direct evidence that aggregated a1piz is removed by autophagy. our findings may have application in the understanding of, and treatment for, individuals with liver disease caused by the accumulation of er aggregates of a1piz. acknowledgements: the study was supported by national science foundation grants mcb-011079 and mcb-0110331. yeast and lactobacillus association generates peptides from acid goat whey proteins fermentation s. didelot, s. bordenave-juchereau, e. rosenfeld, l. murillo, j. m. piot and f. sannier laboratory of biotechnology and bioorganic chemistry, university of la rochelle, la rochelle, france. e-mail: lmurillo@univ-lr.fr our goal was to produce peptides from fermentation of unsupplemented acid goat whey by dairy micro-organisms. we used a lactobacillus, lactobacillus paracasei, and a yeast, candida parapsilosis, both previously isolated from a cheese microflora. when co-cultivated aerobically, both micro-organisms grew on unsupplemented goat whey and led to a medium acidification from 6 to ph 3.5. reversed phase (rp)-hplc analysis revealed a total alpha-lactalbumin hydrolysis after 96 h of fermentation, a modification of the beta-lactoglobulin elution peak, and 2.5-fold increase in peptide level compared with the non-fermented whey. in the absence of c. parapsilosis, l. paracasei grew poorly on whey and only a weak medium acidification from 6 to 4.5 was observed after 192 h of fermentation. rp-hplc analysis revealed a weak modification of beta-lactoglobulin elution peak, a truncated form of alpha-lactalbumin and no peptide generation. c. parapsilosis was able to grow on unsupplemented goat whey without modifying ph of the medium, but only 25% of proteins were hydrolysed (alpha-lactalbumin) or denaturated (beta-lactoglobulin) and, again, no peptides were detected. these results suggest that (i) c. parapsilosis is required for l. paracasei growth and (ii) the co-culture of both micro-organisms is needed to generate peptides from alpha-lactabumin hydrolysis. during co-culture on whey, the use of penicillin g and cycloheximide as bacterial and yeast growth inhibitors respectively, revealed that l. paracasei growth was required for medium acidification to ph 3.5 and alpha-lactalbumin hydrolysis. however, we demonstrated that the protease(s) responsible of alpha-lactalbumin hydrolysis was (were) synthesized by c. parapsilosis during the first stage of fermentation and that medium acidification (obtained either by l. paracasei growth or chemically) was required for yeast protease(s) activity. dengue virus causes widespread human diseases such as dengue fever, dengue hemorrhagic fever and dengue shock syndrome. the viral genome is a positive rna strand that encodes for a single polypeptide precursor. processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by ns3 serine protease. the three dimensional structure of ns3 protease domain ns3pro has been elucidated [1] . recently a new construct of the recombinant form of the ns3pro, was engineered [2] . we have expressed in e. coli the his-tag-cf40.gly.ns3pro protein a new construct of the recombinant form of the ns3pro linked to a 40 -residue co-factor, corresponding to a part of ns2b, via a non-cleavable, flexible non-apeptide (gly 4 sergly 4 ), and have currently optimized the purification procedure. chemically optimized substrates, peptides and depsipeptides, were designed and tested to afford an efficient in vitro activity assay, using hplc and fret spectroscopy. the data suggest that the amino-terminal region of the 40-amino acid co-factor domain is involved in additional charged interactions with ns3 that are essential for activity as previously described. this form showed catalytic activity and spectroscopic studies were performed to identify the folding of the protein. moreover, experiments of limited proteolysis have been performed to identify the essential enzymatic domain of the protein and to stabilize the role of the cofactor in the activity and in folding stabilization of the enzyme. after 2 h of the limited proteolysis with endoproteinase asp-n the product was analyzed by sds-page and activity assay, showing a high reduction of the molecular mass and only a loss of the activity of the 20%. cd and 15 n-1 h-hsqc spectra of this protein fragment were performed and other functional and structural characterizations are in progress in our laboratory. it is intended to obtain the structure in solution of the essential active domain of the uniformly 13 c, 15 n-labeled cf40.gly.n-s3pro by high-field 3d nmr spectroscopy. the solution structure of the enzyme will be used to answer yet unresolved questions about the mechanism of action, the role of its cofactor ns2b, and the observed substrate specificity. introduction: fish consumption is associated to nutritional benefits due to the presence of proteins of high biological value, minerals, vitamins and polyunsaturated fatty acids. most studies concerning the benefits of fish consumption on cancer prevention have focused on fish fatty acids but little is known about the potential bioactivity of fish peptides. the present study was then designed to assess the antiproliferative activity of various fish protein hydrolysates, in order to further purify and characterize anticancer peptides. methods: twenty-one fish hydrolysates (from seven species) produced within the framework of the european valbiomar programm. fish hydrolysates composition (protein, fat and salt content) was determined by standard methods (kjehldhal, soxhlet extraction and volhard respectively). cytotoxic and antiproliferative activity were assayed in vitro on mcf-7/6 and mda-mb-231 human breast adenocarcinoma cell lines, following a cell viability colorimetric assay (promega, france). antiproliferative activity of fish hydrolysates was compared with that of reference anticancer molecules with various cellular targets, namely actino-mycine d, cytosine-beta-d-arabinofuranoside, cyclophosphamide, etoposide, kenpaullone and roscovitine. results: composition analysis revealed that most hydrolysates contained more than 70% protein. three blue whiting hydrolysates containing 96% protein, 0.5% lipid and 0.2% salt induced a strong breast cancer cells growth inhibition when tested at 1 g/l for 72 h in cell culture medium. blue whiting hydrolysates 3, 4 and 5, respectively, induced a growth inhibition of 24.5, 22.3 and 26.3% on mcf-7/6, and 13.5, 29.8 and 29.2 % on mda-mb-231. these in vitro antiproliferative activities are in the range of that observed when the two breast cancer cell lines are treated for 72h with kenpaullone, roscovitine or cytosine-beta-d-arabinofuranoside 10 )6 m. further studies are engaged to fractionate and characterize the antiproliferative peptides contained in blue whiting hydrolysates. during recent years, it has been established that intracellular proteolysis in eukaryotic cells is largely accomplished by a highly selective non-lysosomal pathway that requires atp and a large (2.5 mda) multisubunit complex known as the 26s proteasome. the proteasome-mediated pathway plays vital regulatory functions. it degrades many important proteins involved in cell cycle control, in signaling pathway, and in general metabolism, including transcription factors and key metabolic enzymes. another function of the proteasomal system is the removal of abnormal, misfolded and oxidized proteins generated under normal and, in particular, stress conditions. to date, proteasomes from other than animal or plant cells were studied only in yeast. recently, in our laboratory, the proteasome-mediated pathway was shown to be involved in the regulation of ligninolytic activities in the white rot fungi trametes versicolor and phlebia radiata upon nutrient starvation (staszczak, enzyme microb technol 2002; 30: 537-540). it was the first report on proteasomes in fungi representing basidiomycota. white rot fungi are able to degrade lignin by the action of secreted enzymes, the best characterized of which are laccases, lignin peroxidases, and manganese peroxidases. the subject of lignin biodegradation has commanded attention for a considerable period of time mainly because of its ecological significance and wide industrial applications of bioligninolytic systems. heavy metal ions are important environmental pollutants which affect biodegradation processes performed by white rot fungi. in the present study, we investigated whether the proteasomal degradation pathway might be involved in the regulation of laccase production by t. versicolor in response to cadmium exposure. studies of cacybp/sip function using small interfering rna cacybp/sip was discovered as a protein that bound calcyclin (s100a6) in a calcium-dependent manner (filipek and wojda 1996; filipek and kuznicki, 1998) and its distribution and some biochemical properties have been studied. for instance, it has been shown that cacybp/sip binds calcyclin via its c-terminal fragment (nowotny et al. 2000) and that, beside calcyclin, it interacts with other calcium binding proteins of the s100 family (filipek et al. 2002) . originally, we identified cacybp/sip in ehrlich ascites tumour (eat) cells but it is also present in other mammalian tissues and cells. in particular, high expression of cacybp/sip was found in neuronal cells of mouse and rat brain (jastrzebska et al. 2000) . at present the distribution and structural properties of cacybp/sip are quite well described but its function remains obscure. there is only one paper published concerning the possible involvement of cacybp/sip in b-catenin ubiquitination and degradation (matsuzawa and reed 2001). to elucidate the biological role of cacybp/sip we have designed and synthesized sirna (small interfering rna) against this protein. this sirna was then used to transfect neuroblastoma nb-2a and embryonic kidney hek293 cells, expressing high and low amount of endogenous cacybp/sip respectively. the level of cacybp/sip was monitored in cell extracts by western blot technique. we found that sirna against cacybp/sip, which we designed, inhibited the expression of this protein, as its level in transfected cells was lower in comparison with control cells. at present, we checked the effect of diminished expression of cacybp/sip on b-catenin degradation and other cellular processes. acknowledgements: this work was supported by grants: kbn heavy metals are powerful poisons for living cells. it has been shown that exposure to arsenicals, either in vitro or in vivo, in a variety of model systems, causes the induction of a number of the major stress protein families, such as the heat shock proteins (hsp) (toxicol appl pharmacol 2001; 177: 132). the reasons for heavy metal toxicity in vivo are not fully understood, but they are known to contribute to the accumulation of aberrant proteins (bba,1995,1268, 59). in animal cells, arsenite has been reported to cause sulfhydryl depletion, to generate reactive oxygen species and increase the level of high molecular mass ubiquitin-protein conjugates (toxicol appl pharmacol 2003; 186: 101). in cells submitted to stress conditions, several components of the ubiquitin/proteasome pathway are activated. in this major, eukaryotic proteolytic pathway, multiple ubiquitin molecules are enzymatically ligated to proteins destined for catabolism by an enzyme system composed of three types of enzymes, commonly referred to as e1, e2, and e3. the large ubiquitinprotein conjugates thus formed are subsequently degraded by a very large protease complex, the 26s proteasome, in an atpdependent process. the changes in free ubiquitin (ub) and ubiquitin-protein conjugates (ub-p) levels were followed by immunoblotting during the incubation of the higher plant lemna minor l.(duckweed) in the presence of arsenite (as), at concentrations known to confer thermotolerance to the plants. the observed increase in the amount of large molecular mass ubiquitin-protein conjugates is indicative of a role for the ubiquitin/ proteasome pathway in the response of lemna to as stress. this outcome is primarily attributed to an increased availability in protein substrates during as treatment for three main reasons: an increase in protein carbonyl (a major marker for protein oxidation) content detected by immunoblotting; moderate increments (as determined by semi-quantitative rt-pcr) in the mrna levels of the codifying sequences for the ubiquitin pathway components: ubiquitin, e1, e2 and the b subunit and the atpase subunit of the 26 s proteasome; an identical pattern of variation for the large ubiquitin-protein conjugates is observed in the simultaneous presence of as and cycloheximide, indicating that the observed increase in ubiquitin conjugates does not depend on de novo protein synthesis. ageing and autophagy y. stroikin and a. terman experimental pathology, linko¨ping university, linko¨ping, sweden. e-mail: yurst@inr.liu.se life of aerobic cells is associated with continuous oxidative damage resulting in the formation of altered, non-functional macromolecules and organelles. intracellular accumulation of oxidized proteins defective organelles and lipofuscin inclusions are typical manifestations of ageing that preferentially affects long-lived post-mitotic or growth-arrested cultured cells. autophagy, an important biological mechanism for renewal of damaged intracellular structures, has been found decreased in ageing. to learn more about the role of autophagy in ageing, we studied the effect of the inhibitor of autophagic sequestration 3-methyladenine (3-ma) on human diploid fibroblasts and astrocytes. inhibition of autophagy in growth-arrested (confluent) fibroblasts for 2 weeks resulted in the accumulation of altered lysosomes displaying lipofuscin-like autofluorescence, especially when 3-ma exposure was combined with hyperoxia. the findings suggest that autophagy is indispensable for normal turnover of lysosomes, and lysosomal components may be direct sources of lipofuscin. the accumulation of oxidatively damaged intracellular structures (so-called biological ''garbage'') was associated with decreased cell viability. two-week-inhibition of autophagy with 3-ma resulted in a significantly increased proportion of dying cells when compared with both untreated confluent cultures and dividing (subconfluent) cells exposed to 3-ma. similar results were obtained when autophagic degradation was suppressed by the protease inhibitor leupeptin. the results support the idea that biological ''garbage'' accumulation is essential for ageing and age-related death of post-mitotic cells, which can be prevented by cell division. recently two family members of the tumour suppressor gene p53 have been described, p63 and p73, which seem to be necessary for specific p53-induced stress-response pathways. furthermore, p63 and p73 appears to be crucial to determine the cellular sensitivity to anticancer drugs, particularly in tumours lacking functional p53. here, we show that p63 and p73 isoforms are also regulated by proteasomal degradation. we have identified several e3-ubiquitin ligases responsible for the regulation of the stability of p63 and p73. we found that the regulation of p63 and p73 is isoform-specific. furthermore, we demonstrate that ubiquitination of p73 influences the cellular localization of p73 and of the respective e3-ubiquitin ligases. finally, we show that the expression of the various e3-ubiquitin ligases can be differentially induced by p73-isoforms. in addition, the e3-ubiquitin ligases can influence the apoptotic function of p73. our findings demonstrate that p63 and p73 are sent to degradation or stabilized by e3-ubiquitin ligases in an isoform-specific manner and we suggest a negative feedbackloop between p63, p73 and their regulators, as they also influence the function of p63 and p73. increased level of metalloproteases was shown to accompany tumor angiogenesis and active invasion in adjacent tissue [1] . development of different types of tumors is often accompanied by increased protease activity in blood [2, 3] . in the present study we compared protease activity of plasma and eluate from surface of blood cells in healthy donors and patients with breast tumor. we have demonstrated recently that in blood of healthy donors almost all circulating nucleic acids (cirna) are bound at the surface of blood cells. in patients with fibroadenoma cirna were found at cell surface whereas in breast cancer, no cell-surfacebound cirna were detected in blood [4] . conjugates of hydrophobic and hydrophilic peptides of cd34 receptor with biotin were incubated with avidin-coated 96-well eia microplates. avidinpeptide complex was incubated with samples under investigation and serial dilutions of proteinase k solution, which was used for calibration of protease activity. undegraded peptides were visualized by incubation with goat anti-peptide antibodies followed by conjugate of anti-goat immunoglobulins with peroxidase. blood plasma and eluate from surface of blood cells of cancer patients demonstrated increased level of anti-hydrophilic protease activity compared with healthy donors. increase of protease activity against hydrophilic peptide in blood correlate with decrease of cell-surface-bound cirna, indicating that blood proteases can affect concentration and distribution of circulated na. identification of cleavage site and natural substrate specificity of prta, a serralysin-type metalloprotease from the entomopathogenic microorganism photorhabdus prta, a secreted basic metalloprotease of photorhabdus, belongs to the m12b (serralysin) family of proteases. the biological function of these enzymes is not known, but in some cases they are supposed to have a role in virulence. serralysins are generally assumed to have broad substrate side-chain specificity. attempts toward the generation of a sensitive and specific substrate of these enzymes had limited success, and no such substrate is available for prt-a. through mass spectrometric analysis of prta cleavage products of oxidized insulin a and b chain, we found that prta has a welldefined cleavage site preference. based on this, we developed a sensitive and highly specific oligopeptide substrate through optimization of the amino acid composition and length. the kinetic parameters of prta isolated from photorhabdus luminescens ssp. laumondii strain brecon were measured on the best substrate, dabcyl-glu-val-tyr-ala-val-glu-ser-edans, giving a km of 8.8 · 10 )5 , a kcat of 2.1 · 10 )2 /s and a kcat/km of 2.4 · 10 6 . its poor hydrolysis by various proteases proved its specificity, while it was very sensitivity in measuring prta activity in hemolymph samples from photorhabdus infected galleria mellonella larvae. the substrate preference of prt-a was determined by in vivo digestion of hemolymph proteins from manduca sexta. six minor protein components were selectively cleaved, which were provisionally disthe epithelial sodium channel (enac) is an integral component of the pathway for na + absorption in epithelial cells. enac activity is mainly regulated by mechanisms that control its expression at the cell surface, such as ubiquitination. the ubiquitin ligases nedd4 and nedd4-2 have both been shown to bind to enac and decrease its activity. conversely, the serum-and glucocorticoid regulated kinase (sgk), a downstream mediator of aldosterone, is able to increase enac activity. this effect is at least partly mediated by direct interaction between sgk and nedd4-2. sgk binds both nedd4 and nedd4-2 but it is only able to phosphorylate nedd4-2. phosphorylation of nedd4-2 reduces its ability to bind to enac, and hence increases enac activity. the impact of the interaction between nedd4 and sgk remains unclear. nedd4-like proteins interact with enac via their ww-domains. these domains bind py-motifs (ppxy) present in enac subunits. nedd4 and nedd4-2 both have four highly homologous ww-domains. previous studies have shown that interaction between nedd4 and enac is mainly mediated by ww-domain 3. sgk also has a py-motif, therefore we tested whether the ww domains of nedd4 and nedd4-2 mediate binding to sgk. we show that single or tandem ww domains of nedd4 and nedd4-2 mediate binding to sgk and that, despite their high homology, different ww domains of nedd4 and nedd4-2 are involved. our data also suggest that ww domains 2 and 3 of nedd4-2 mediate the interaction with sgk in a concerted manner, and that in vitro the phosphorylation of sgk at serine residue 422 increases its affinity for the ww domains of nedd4-2. the stimulatory effect of sgk on enac activity is partly mediated via nedd4-2 and will decrease if competition between nedd4 and nedd4-2 for binding to sgk occurs. we show that nedd4 and nedd4-2 are located in the same subcellular compartment and that they compete for binding to sgk in vitro. the concerted or successive action of proteolytic enzymes has been described in a number of important biological processes in which proteins are degraded or matured, such as digestion, turnover (lysosomal, proteosomal...), blood coagulation, developmental remodeling or apoptosis, among others. the complementary action of proteases belonging to different families to achieve a more efficient o a better modulated hydrolytic mechanism is well documented. specific molecular associations or shared scaffolds between the involved proteases and/or protein inhibitors and defined three-dimensional structures have also been reported. however, only in a few cases such structures involved metallo.carboxy-peptidases or their inhibitors [1] . we shall review this subject and describe, in such a context, a new model found in a marine invertebrate organism in which such a fact takes place. in particular, the characteristics of a novel bifunctional molecule displaying the functionalities and structures of serine-and metallo.carboxy-peptidases will be presented. its structure is fully different than the ones previously reported by us and collaborative groups for metallocarboxypeptidase inhibitors [2] [3] [4] . regulating the activity of herpes virus proteases c. s. craik departments of pharmaceutical chemistry, pharmacology, and biochemistry and biophysics, ucsf, san francisco, ca, usa. e-mail: craik@cgl.ucsf.edu herpesviral proteases exist in a monomer-dimer equilibrium in solution. dimerization is required for activity and a comformational change communicates the oligomerization state of the enzyme to the active site of each intact monomer. each monomer has an active site, which is spatially separate from the dimer interface. kaposi's sarcoma-associated herpesvirus (kshv), encodes a protease (kshv pr), which is necessary for the viral lytic cycle. like those of other herpesvirues proteases, the dimer interface of kshv pr is composed primarily of a helix near the c terminus, of the protein. the helix of one monomer interacts with residues in the symmetrically related helix of the other monomer across the dimer interface as well as with neighboring helices. small molecule inhibitors, site directed mutagenesis and 2d nmr spectroscopy were used to compare the monomeric and dimeric forms of kshv pr and to investigate the relationship of the active site and the dimer interface of the enzyme. active site inhibition was shown to strongly regulate the binding affinity of the monomer-dimer equilibrium of the protease, shifting the equilibrium completely to the dimeric form of the enzyme. a previously undetermined conformational change provided insight in to the regulation of protease activity by dimerization as well as an explanation for the weak dimerization of a family of enzymes with a disparately large dimer interface compared to their measured binding affinities. using this information as a guide, protein grafting of the interfacial helix onto a small stable protein, avian pancreatic polypeptide, generated a small macromolecular inhibitor that successfully disrupted the dimer interface and inhibited enzymatic activity. these results provide direct evidence that peptide bond hydrolysis is integrally linked to the quaternary structure of the enzyme, validate the protease as a therapeutic target and suggest the dimer interface may be an alternative site for antiviral design. abteilung strukturforschung, max-planck-institut fu¨r biochemie, martinsried, germany. e-mail: huber@biochem.mpg.de proteolytic enzymes catalyze a very simple chemical reaction, the hydrolytic cleavage of a peptide bond. nevertheless they constitute a most diverse and numerous lineages of proteins. the reason lies in their role as components of many regulatory physiological cascades in all organisms. to serve this purpose and to avoid unwanted destructive action proteolytic activity must be strictly controlled. control is based on different mechanisms which i will discuss and illustrate with examples of systems and structures determined in my laboratory. the family of serine protease inhibitors known as the serpins is represented in all branches of life and predominate in the higher organisms, including man. they have evolved an extraordinary mechanism to inhibit proteases which distinguishes them from the 20 other families of serine protease inhibitors, and renders them uniquely qualified to control of the proteolytic pathways essential to life. the mechanism is best described as a spring-loaded mousetrap, where nibbling of the peptide loop bait springs the trap and crushes the unsuspecting protease. as with a mousetrap, the active state of a serpin is metastable, and the energy released upon conversion to its more stable form is used to trap the protease. the complexity of the serpin mechanism provides many advantages over the simpler lock-and-key type mechanism, utilized by all other serine protease families. serpins provide stoichiometric, irreversible inhibition, and the dependence on serpin and protease conformational change is exploited for signaling and clearance. the potential for regulation is also an inherent part of such a complex mechanism, as illustrated by the heparin activation of serpins antithrombin and heparin cofactor ii. however, with complexity of mechanism also comes susceptibility to disease causing mutations: both through loss-of-function, as with thrombosis caused by antithrombin deficiency; and gain-of-function, as with dementia caused by neuroserpin polymerization. many crystallographic structures of serpins have been solved over the past 20 years, and we now have a frame-by-frame cinematic view of the intricate conformational rearrangements involved in protease inhibition, modulation of specificity, and molecular pathology of the remarkable shape-shifting serpins. structural lessons of serine proteases: function and mechanism of the serine protease-like hgf as a growth factor in met signaling hepatocyte growth factor (hgf), a plasminogen-related growth factor, is the ligand for met, a receptor tyrosine kinase implicated in development, tissue regeneration and invasive tumor growth. hgf acquires signaling activity only upon proteolytic cleavage of single-chain hgf into its a/b-heterodimer, similar to zymogen activation of structurally related serine proteases. although both chains are required for activation, only the achain binds met with high affinity. recently, we reported that the protease-like hgf b-chain binds to met with low affinity this suggests that additional allosterically linked regions may be involved in the signaling process. furthermore, antibodies directed toward the b-chain or the hgf a-chain result in inhibition of met phosphorylation in a549 cells. these antibodies also inhibit proliferation in bxpc3 cells and baf3 cells. implications for dimerization mechanisms of hgf-dependent met receptor activation and signaling are presented. in addition, mutagenesis of the hgf b active site region has been investigated with respect to imparting enzymatic activity. thus while hgf has the function of a growth factor, the structural and receptor binding aspects of hgf are more akin to those of serine proteases. trypsinogen 4 with a 28 amino acid leader peptide on its n-terminus is the predominant form of the enzyme in human brain gene prss3 on chromosome 9 of the human genome encodes, due to alternative splicing, both mesotrypsinogen and trypsinogen 4. mesotrypsinogen has long been known as a minor component of trypsinogens expressed in human pancreas, while the mrna for trypsinogen 4 has recently been identified in brain and other human tissues. analysis of the gene encoding trypsinogen 4 predicted two isoforms of the zymogen: isoform a may have a 72 amino acid, while isoform b a 28 amino acid n-terminal leader sequence. the translation initiation site for isoform a is an atg codon, while the initiation site predicted for isoform b is a ctg codon. we measured the amount of trypsinogen 4 mrna and the quantity of the protein as well in 17 selected areas of the human brain. trypsinogen 4 could be localized in glial and neuronal cells using immunohistochemical methods. we purified human trypsinogen 4 by affinity chromatography. our results show that splice isoform b is the predominant if not the exclusive form of the zymogen in human brain. the n-terminal residue of the isolated protein was identified by amino acid sequencing as a leucine. at the same time the longest mrna we were able to isolate was barely longer than the one corresponding to splice isoform b. although the most trivial explanation of our results is that isoform a is proteolytically processed to result in isoform b, it cannot be excluded that leucine rather then methionine is used as translation initiator amino acid. search for endogenous substrates for prolyl oligopeptidase in porcine brain prolyl oligopeptidase (po) is a serine protease present in most tissues, which preferentially cleaves the peptide bond at the carboxyl site of proline residues. the function of po is unknown, but it has been associated with several disorders of the central nervous system, such as depression and alzheimer disease. the purpose was to look for endogenous substrates for the recombinant porcine po in porcine brain. we adapted a method to extract the proteins from the brain with special attention to the smaller polypeptides since po is not known to cleave peptides larger than 30 amino acids. subsequently we looked for a method to separate the protein mixture in less complex fractions. 2d-gelelectrophoresis, commonly used in proteomics, is only suitable for proteins with a molecular weight between 10 and 200 kda and an iso-electric point between 4 and 10. two-dimensional chromatography offers a suitable alternative for small peptides. we chose ion exchange chromatography as a first and reversed phase high pressure liquid chromatography as a second step. the resulting fractions were divided into two parts. one part was incubated with the purified po, the other served as a control. by looking for shifts in the mass spectrum between the control sample and the incubated sample, we identified peptides cleaved by po. different methods, such as esi-qtof-ms and maldi-toftof-ms, were used to sequence cleaved peptides by msms. these experiments allowed us to deduce the sequence requirements for po cleavage. serine protease subtilisin immobilized on novel mesoporous materials serine proteinases are widely used in protein mapping and peptide or ester bond formation. fixation of enzyme on solid support has many advantages, such as high stability, possibility of recovering and low product contamination by enzyme. subtilisin carlsberg, a protease from bacillus licheniformis, was immobilized on mesoporous silica (sba-15) and several organosilica supports via physical adsorption. the bifunctional mesoporous organosilicas containing ch2-ch2 or ch=ch bridges in combination with organic tethers bearing amino or hydroxyl functionalities were synthesized using supramolecular templating in the presence of non-ionic triblock copolymers and exhibited high surface area and large pore diameters in the range of 50-70 å suitable for the incorporation of subtilisin. the kinetics of immobilization was examined for six different carriers. it was shown that enzyme retained hydrolytic activity after the immobilization. the dependence of subtilisin loading on the starting concentration of the enzyme during adsorption shows the maximum loading (455 mg protein/g support) at [e] = 20 mg/ml. the ph dependences of loading and activity of immobilized biocatalysts were bell-shaped. for the organosilica support containing amino and hydroxyl groups the ph-dependence was shifted to the alkaline ph by 2 in comparison with the support containing ch2-ch2 bridges. the adsorbed subtilisin desorbs easily in aqueous media, while no leaching of the enzyme was observed in acetonitrile and dmf/acetonitrile mixture (6/4). the immobilized biocatalyst shows high hydrolytic activity after incubation in non-aqueous acetonitrile for 1 week and after 48 h incubation in 60% dmf/acetonitrile mixture. these data indicate a possible application of the obtained biocatalysts in low water media. purification, structural and biological characterization of protease inhibitors from acacia plumose seeds protease inhibitors have been used in many current medicines. therefore, there is a considerable interest inside the pharmaceutical industry in discovering new composites and mechanisms of protease inhibition, since these investments have led, for example, to new anti-hiv therapeutical tests, coagulation diseases treatment and tests with anti-carcinogenic drugs. serine protease inhibitors are found in all plant tissues, mostly in the seeds of the leguminosae subfamilies: mimosoideae, caesalpinoideae and papilionoideae. acacia genus is one of most important member of mimosoideae, and the presence of protease inhibitors in this genus was described in only three species and none of them were structurally characterized. in this sense, we are studying three new protease inhibitors from a. plumose seeds. from saline extract of triturated mature seeds the inhibitors were purified and presented anti-coagulant activity, serine protease inhibitory activity and action on growth of fitopathogenic microorganisms, in vitro. the purification steps included size exclusion chromatography on the superdex-75 column, equilibrated and eluted with pbs, a ionic exchange chromatography on mono-s (hr 5/5) column, equilibrated with the buffer sodium acetate 50 mm (ph 5.0), and eluted with the same buffer in a gradient of 0-0.5 m of nacl. three fractions (eluted around 0.18, 0.22 and 0.33 m of nacl) that presented anticoagulant activity and serine protease inhibition were separated and denoted apia, apib and apic. their apparent mws were around 20 kda, by sds-page in the absence of reducing agents. in the presence of reducing agents they shown two bands: between 14-22, and 8-6 kda. the n-terminal analyze of higher mw chains were tyafl (apia); kellvdne (apib) and telhdd (apic). the circular dichroism spectra of these inhibitors were very similar, presenting a maximum around 230 nm and a minimum in 202 nm, compatible with presence of unordered and beta elements of secondary structure. their nterminal, cd spectra and two-polypeptide chains linked by covalent bound, are compatible with kunitz type inhibitors. probably these inhibitors are three different isoforms that present different inhibition specificity degree on the serine proteases family. the ki to different serinoproteases (trypsin, plasmatic kalikrein, elastase, quimotrypsin) and specificity to the phytopatogenic fungus are being investigated. although the proteases were initially described as enzymes involved in the non-specific degradation of dietary proteins, today it is known that they can also act as highly specific enzymes that perform selective cleavage of specific substrates. thus, alterations in the structure, regulation or function of this type of enzymes underlie serious human disorders including cancer. to date, more than 550 protease and protease homologs are annotated in man, mouse, and rat genomes (www.uniovi.es/degradome). the increasing complexity of the proteolytic systems has led to the introduction of global concepts as the term degradome to define the complete set of proteases that are produced in a specific moment by a cell, tissue or organism. as part of our studies focused on the characterization of the mammalian degradomes, we have identified and cloned unusual mosaic proteases containing in tandem serine protease domains. the first, called polyserase-1 is synthesized as a transmembrane protein that undergoes post-translational events to generate three independent serine protease domains. the second polyprotease is the polyserase-2, a secreted protein that remains as integral part of the initial protein product. to date, it is difficult to understand the putative functional advantages derived from the complex polyproteases and, albeit extremely unusual, it is not an unprecedented situation. thus, the amphibians ovochymase and oviductin are polyserine proteases that contain three in tandem serine proteases. in humans, angiotensin-coverting enzyme and carboxypeptidase d are polymetalloproteases that exhibit some similarities to the polyserases. all these polyproteases constitute examples that illustrate an additional strategy for increasing the complexity of the degradomes. evolution of a genetic locus, expressing several protease inhibitors with homology to whey acidic protein (wap) a. clauss and å . lundwall department of laboratory medicine, lund university, malmo¨, sweden. e-mail: adam.clauss@klkemi.mas.lu.se we have previously described a locus on human chromosome 20 that gives rise to 14 proteins containing wap four disulphide core (wfdc) domains. among them are the elastase inhibitors elafin and secretory leukocyte proteinase inhibitor (slpi). both slpi and elafin are also known to be important components of the innate immune defence by displaying anti-microbial properties. in order to gain a deeper understanding of the biological role of the locus, we have now extended our investigations of its organization and evolution into non-human mammals. homologous loci were identified on mouse chromosome 2, rat chromosome 3 and dog chromosome 24. transcript sequences were generated by race technology or retrieved from the est databases. as in humans, the murine and canine loci are divided into two sub-loci separated by approximately 200 kb. the majority of genes are conserved in all species, but the comparison also showed gain and loss of genes, e.g. two human pseudogenes were identified due to the discovery of functional rodent genes, and in the rat several duplications has yielded four slpi genes. a most interesting finding was that there is no murine elafin gene. the different wfdc domains showed a highly variable species conservation. this was particularly striking in proteins containing multiple domains, where the aminoterminal wfdc generally displayed low conservation, whereas the opposite was true for the carboxyterminal wfdc. the difference could be due to the potential targets of the inhibitors, which might be either highly variable exogenous microbial proteases or conserved endogenous proteases. signaling mechanism of thrombin-induced human gingival fibroblast contraction thrombin is activated during gingival tissue injury and inflammation. thrombin and other bacterial proteases also affect the functions of adjacent periodontal cells via stimulation of proteaseactivated receptors (pars). we noted that thrombin and par-1 agonist peptide (20 lm) induced the gingival fibroblasts (gf)-populated collagen gel contraction within 2-h of exposure. however, par-3 and par-4 agonist peptide (<20 lm) show little effect on collagen gel contraction. u73122 (phospholipase c inhibitor) and 2-apb (ip3 antagonist) were effective in inhibition of gf contraction. thrombin-induced gf contraction was inhibited by 5 mm egta (an extracellular calcium chelator) and verapamil (a l-type calcium channel blocker). in addition, w7 (10 and 25 lm, a calcium/calmodulin inhibitor), ml-7 (50 lm, myosin light chain kinase, mlck inhibitor), and ha1077 (100 lm, rho kinase inhibitor) completely inhibited the thrombin-induced collagen gel contraction. thrombin also induced the phosphorylation of erk1/erk2 in gf. however, u0126 only partially inhibited the thrombin-induced gf contraction. similarly, wortmannin (100 lm), ly294002 (20 lm) (two pi3k inhibitors) and genistein, also showed partial inhibition. moreover, nac was not able to suppress the gf-contraction, as supported by slightly decrease in reactive oxygen species production in gf by thrombin. these results indicate that thrombin is crucial in the periodontal inflammation and wound healing by promoting gf contraction. this event is mainly mediated via par-1 activation, plc activation, extracellular calcium influx via l-type calcium channel, and the calcium/calmodulin-mlck and rho kinase activation pathway. survival of the anticarcinogenic bowman-birk inhibitor from soybean at the terminal ileum of cannulated pigs plant protease inhibitors (pi) of the bowman-birk class, a major pi class in legume seeds, have emerged as highly promising cancer chemopreventive agents, being capable of preventing or suppressing carcinogenic processes in a wide variety of in vitro and in vivo animal model systems. in order to exert their chemopreventive properties in vivo, plant pi have to resist and survive, at least to some extent, degradation by acidic conditions and digestive enzymes during gut passage. in this study, we have evaluated the survival rate of the bowman-birk inhibitor (bbi) in the terminal ileum of cannulated pigs fed defatted soybean. two different quantitative approaches have been carried out. firstly, a competitive indirect elisa assay using an antisera capable to detect bbi free and/or in complex with digestive proteases; secondly, we have carried out spectrophotometric measurements of trypsin and chymotrypsin inhibitory activities in ileal samples, where the presence of bbi metabolites and/or single active loops can be detected. according to the elisa method, ileal apparent digestibility of bbi was 58 %, which resulted in a recovery of 0.61 mg out of 1.5 mg/kg feed ingested. significantly higher ileal digestibility values (95 %) were found when trypsin and chymotrypsin inhibitor activities were evaluated. the results suggest that the immunoassay may be overestimating the presence of functional pi by detection of inactive bbi, but also that the presence of complexed bbi with digestive proteases, even if protein extraction was carried out under acidic conditions, could make bbi undetectable in activity assays. studies are in progress to overcome these drawbacks. the resistance of bbi to the acidic conditions and digestive enzymes of the upper gastrointestinal tract make these proteins very interesting candidates for evaluation as chemopreventive agents, in modulating cell viability and tumor progression within the gastrointestinal tract. a single amino acid change in a chymotrypsin prevents plant proteinase inhibitor binding plants have evolved economical strategies to combat insects, which on one hand involves the production of multi-domain pis that can target multiple enzymes with different specificities and on the other, pis that belong to structurally distinct families. solanaceous plants, produce both type i and type ii families of pis, which specifically target serine peptidases. this study showed that type i pis are better inhibitors of a particular class of chymotrypsins within the gut of helicoverpa species that is otherwise unaffected by the type ii class of inhibitors. homology models were used to identify a single amino acid substitution in the helicoverpa chymotrypsin that was likely to confer resistance to the type ii inhibitor. our hypothesis was further supported by recombinant expression and mutagenesis of this single amino acid in the type ii inhibitor-resistant chymotrypsin. we therefore propose that both type i and ii inhibitors are required to protect plants against lepidopteran insects. mobility of the sulphate protamin/ low molecular weight heparin complexes in an electrical field glycosaminoglycans low molecular weight heparin (lmwh) activated plasma serine proteases inhibitors. serine proteases play an important role in thrombogenesis, the process that leads to blood clotting and such as heart attack, stroke and other cardiovascular disorders. lmwh has been used to temporarily render the blood incoagulable during prophylaxis or treatment of thrombosis and sometimes result in serious bleedings and for the heparin anticoagulant activity neutralization used sulphate protamin. it was investigated relationship between new lmwh-sk derivatives (were generated through the controlled cleavage of porcine intestinal mucosa heparin with a mixture of chitinolytic complex from streptomyces kurssanovii) anticoagulant activities and lmwh-sk complexes with sulphate protamin mobility in an electrical field. with this purpose used biospecific electrophoresis in 1% agarose with protamin sulphate. precipitation zones (zones of the equivalent) in the ''rocket'' form were generated. scanning image was saved as jpg format. the ''rocket'' squares estimated with the help of bandscan program. results: lmwh-sk with molecular mass (mm) 14.0; 5.8; 5.4; 4.7; 4.0; 3.4 kd demonstrated antithrombin activities (aiia) 85-264 iu/mg, activities against factor xa (axa) has made 100-278 iu/mg, axa/aiia ratio -(0.8-2.2). correlation coefficients between mm and precipitation zone heights or squares consist 0.56-0.73 (p < 0.05), between axa activities and precipitation zone heights or squares consist 0.37-0.54 (p < 0.05). conclusion: lmwh-sk was obtained with the chitinolytic comlex hydrolisis help has ratio axa/aiia-2,2, it is necessary for antithrombotic preparations. with the mm decrease axa activity increase and precipitation zone heights or squares of the lmwh-sk complexes with sulphate protamin decrease. the role of extracellular proteases in supplying filamentous fungi with nutrient compounds is well understood and experi-mentally documented. however there is no definite answer on the question on the need and role of these proteases in pathogenesis. the study of differences in the spectra of extracellular enzymes of saprotrophic and pathogenic fungi performed on fusarium species revealed that activity of secreted serine proteinases of pathogenic f. culmorum strain was much higher (up to 20-fold) than that of saprotrophic strain. the use of f. culmorum strains differing in pathogenicity (strongly and weakly pathogenic) demonstrated that activity of secreted serine proteases of strongly pathogenic strain was significantly higher (1.5-8-fold) than that of weakly pathogenic strain. this tendency was preserved in calculations of activity towards protein content and dry weight of mycelium indicating on purposeful synthesis and secretion of extracellular proteases by strains with high pathogenicity. at that these differences were much higher when the substrate for trypsin-like proteinases bz-arg-pna was used than in the case of substrate for subtilisin-like proteinases glp-ala-ala-leu-pna. according to the data obtained it is proposed that the value activity of trypsin-like proteinases secreted by the fungi correlated with the degree of their pathogenicity and plays, apparently, an important role in pathogenesis. acknowledgment: this work was supported by grants from the russian foundation for basic research. conformational adaptation of a canonical protease inhibitor upon its binding to the target protease increases specificity atomic resolution crystal structure of sgti in complex with crayfish trypsin provided further data on the molecular basis of the inhibition mechanism of pacifastin type inhibitors. in complex with crayfish trypsin, sgti exhibits more or less continuous contacts in an extended region (through sites p 12 -p 5' ) of the molecule. the comparison of this complex with a simulated bovine trypsin-sgti one shows that more than half of the interaction energy surplus is originated from the extended region of binding. some of these contacts result from a conformational change of sgti that was induced by its binding to the enzyme which is strongly supported by the critical comparison of the crystal structure of crayfish trypsin-sgti complex with the free form of sgti. alignment of the nmr structure ensemble with the x-ray structure of complexed sgti and a careful comparison of the backbone j, w angles were carried out. additionally, noe-derived restraints and corresponding distances in the complex are also compared. local conformation of both p 12 -p 4 and p 4 '-p 5 ' regions of the inhibitor shows significant changes upon binding suggesting that either or both of these regions may act as molecular recognition sites. this comprehensive analysis of the local backbone properties of sgti in the free and in the complex form made possible to identify conformational similarities and differences responsible for its efficient binding to the enzyme, and provides a good basis for further studying the structural aspects of protease inhibitor specificity. as most of serine proteases enteropeptidase light chain contains four disulfide bonds and one nonpaired cysteine at 122 (chymotrypsinogen-derived residue numbering) position which forms disulfide bond linking the pro-and catalytic domains. a mutant of human enteropeptidase light chain cys122ser was constructed by site-directed mutagenesis. the recombinant wild type and mutant proteins were produced in escherichia coli bl21(de3) with expression vector pet-32a. the active proteins were obtained after solubilization and renaturation of the fusion protein thioredoxin/human enteropeptidase light chain from inclusion bodies. after autocatalytic cleavage of thioredoxin the active enzyme was purified on agarose linked soybean trypsin inhibitor. the yield of refolded active enzyme increased from 1.87 to 7.84% in case of cys122ser mutant. the wild type and c122s mutant showed similar kinetic parameters for cleavage of small synthetic substrate gly-asp-asp-asp-asp-lys-naphthylamide, small ester thiobenzyl benzyloxi-carbonil-l-lysinate (z-lys-sbzl) and fusion protein cleavage. both enzymes were inhibited by trypsin-like serine proteases inhibitors but not inhibitors of chymotrypsin-like, cysteineor metallo-proteinases. recombinant human enteropeptidase light chain and its mutant c122s were active between ph 6 and 9 with a broad optimum at about ph 7.54 and demonstrated quite high stability to different denaturating agents. both enzymes demonstrated secondary specificity to chromogenic substrate z-ala-phe-arg-na with km = 0.067 mm, kcat = 23 s-1. proteinaceous low molecular serine protease inhibitors from wood rotting fungi k. j. grzywnowicz and j. zuchowski biochemistry department, maria curie-sklodowska university, lublin, poland. e-mail: grzyw@hermes.umcs.lublin.pl proteolytic enzymes have been firmly established as main regulatory components in a number of cellular and physiological processes. the most important factors influencing the proteolytic enzymes are natural, proteinaceous protease inhibitors, which form complexes with target proteases. they have been extensively investigated from the points of view on physiological functions, as tools for protease enzymology, models for protein-protein interactions and on potential medical applications. there is growing interest in new inhibitors of proteases from various sources. among known protease inhibitors from fungi are, yeasts inhibitors of proteinases a (asparagine protease) and b (serine protease), and low molecular inhibitors of serine proteinases from fruiting bodies of mushrooms -pleurotus ostreatus and lentinus edodes as well as some undefined proteinase inhibitory activities from water extracts of some species of basidiomycetes. searching for new, bioactive metabolites of basidiomycetous fungi we isolated and characterized recently some low molecular, proteinaceous, natural inhibitors of serine proteases, from mycelia of wood rotting fungi -trametes versicolor, abortiporus biennis and schizophyllum communae. isolation of inhibitors was achieved by ion exchange and size exclusion chromatography. preliminary characterization of their inhibitory activity (against some serine proteases), ph and temperature optima of action, and molecular mass, were classically analyzed. analysis of n-terminal amino acid sequences of these inhibitors suggests a new family of serine protease inhibitors from fungi. more detailed characterization of inhibitors (including molecular modeling) and preliminary experiments with laboratory animals and with lines of human cells are in progress. the role of serine proteases in the lectin pathway of complement activation p. ga´l 1 , g. ambrus 1 , v. harmat 2 , b. ve´gh 1 , g. na´ray-szabo´2, r. b. sim 3 and p. za´vodszky 1 1 institute of enzymology, hungarian academy of sciences, budapest, hungary, 2 protein modeling group, hungarian academy of sciences, budapest, hungary, 3 department of biochemistry, university of oxford, oxford, uk. e-mail: gal@enzim.hu the complement system is a cascade of serine proteases, and mediates essential functions during infection as a part of the innate immunity. activation of the complement system culminates in the destruction and clearance of invading microorganisms and damaged or altered host cells. our view about the complement system has changed considerably in the recent years, due to the discovery of a new activation pathway of complement: the lectin pathway. we have recombinantly expressed and characterized the mannose-binding lectin associated serine proteases: masp-1 and masp-2. these are related mosaic serine proteases with similar domain organization but with different enzymatic properties. we showed that masp-2 is capable of autoactivation and it can cleave c2 and c4 complement subcomponents. masp-2, therefore, can initiate the complement cascade without the contribution of any other protease. we demonstrated that the complement control protein (ccp) modules, which associate directly with the serine protease domain, stabilize the structure of the catalytic region masp-2 and contain exosites for the large protein substrates. these results are in agreement with the crystal structures of activated and zymogen forms of masp-2. masp-1 is the most abundant mbl-associated serine protease but it cannot activate the complement system. we demonstrated that masp-1 has a more relaxed substrate specificity compared to masp-2 and the activity of both proteases can be blocked by c1-inhibtor. we concluded that the two mbl-associated serine proteases participate in evolutionary and functionally different pathways. comparative kinetic study on s2' trypsin variants l. gombos, j. tó th, p. medveczky, a. ma´lna´si csizmadia and l. szila´gyi laboratory of enzymology, department of biochemistry, eo¨tvo¨s lora´nd university, budapest, . e-mail: gl@ludens.elte.hu by far the most serine proteases have a glycine in position 193, which is part of the s2' subsite (the second subsite on the enzyme surface c-terminal from the scissile bond of the substrate). in contrast, human trypsin 4, the trypsin isoform expressed in human brain, possesses an arginine in that position. the bulky side chain of this amino acid is responsible for the inhibitor resistance, the most striking feature of this isoform, as it interferes with the binding of polypeptide inhibitors to the enzyme surface. a chimpanzee typsin also has an arginine193, while rat trypsin v bears a tyrosine in that position. there is also a snake venom plasminogen activator, a trypsin type serine protease, that contains an s2' phenilalanine. we created glycine, arginine, tyrosine and phenilalanine s2' variants of human and rat trypsins by site directed mutagenesis in order to investigate the effect of these amino acids on the kinetic behaviour. on small chromogenic substrates and synthetic inhibitors, which do not interact with the s2' residue, there is no signifi-cant difference between the various mutants in catalytic efficiency and inhibitory constants, respectively. however, on oligopeptide substrates the catalytic efficiency decreases 20-50-fold in the nonglycine variants. this effect is even more dramatic with polypeptide partners: the catalytic efficiency drops 200-500 times while inhibitory constants increase by 3-5 orders of magnitude. we conclude that the catalytic mechanism is not fundamentally influenced by the substitution of residue 193, although this amino acid is part of the oxyanion hole. bulky residues in the s2' subsite hinder mainly the binding to interaction partners. structural studies on masp-2: towards the understanding of the mechanism of autoactivation mannose-binding lectin-associated serine protease 2 (masp-2), is the key enzyme of the lectin activation pathway of complement, a major element of innate immunity. a dimer of masp-2 complexed with mannose-binding lectin (mbl) is able to perform its biological functions: upon recognition of the pathogen by mbl masp-2 undergoes autoactivation, and then initializes the complement cascade by cleaving c2 and c4. masp-2 is a mosaic protein containing a chymotrypsin like serine protease domain (sp) and further domains with binding sites of mbl or substrates. our present study focuses on the structural background of the ability of the zymogen form of masp-2 to undergo autoactivation. we solved the structures of catalytic fragment of masp-2 both in its zymogen and activated forms. comparison of the two structures reveals characteristic conformational differences in the classical activation domain and in some other loops lining the substrate binding region. loop 1 shows a unique conformation with arg192 blocking the s1 pocket. we docked the activation loop of masp-2 in the active site of the active enzyme and built a model of the complex of the active and zymogen forms. the model reveals extended regions of molecular recognition. while this model represents the second step of autoactivation (active form cleaves zymogen), the first step (zymogen cleaves zymogen) requires the stabilization of the zymogen enzyme in active-like conformation. we built a model of a zymogen-zymogen complex. favorable and unfavorable contacts of the two zymogen molecules help us to identify possible molecular switches, as well as contact regions stabilizing an active-like conformation of the zymogen enzyme in the complex. the deg/htra proteases are atp-independent serine endopeptidases which are present in most organisms, including bacteria, humans and plants. previous work in our laboratory has shown that the deg2 protease of the model plant arabidopsis thaliana selectively degrades the photodamaged d1 protein in the reaction center of photosystem ii (psii) in vitro. therefore, deg2 is thought to catalyze the primary cleavage of photodamaged d1 protein, which is an important step of the repair mechanism that restores functional psii. our present studies aim to elucidate the regulation of the deg2 protease activity, especially with regard to its d1 degrading activity. we found deg2 associated to the stromal side of the thylakoid membranes and as a soluble protein in the chloroplast stroma. the amount and distribution of deg2 protein remained unchanged after exposure to different light intensities, which suggest either a substrate regulation or a posttranslational regulation of the d1 degrading activity of deg2. recent advances on deg2 regulation and complex formation will be presented. novel peptide inhibitors of human kallikrein 2 (hk2) human kallikrein 2 (hk2) is a serine protease produced by the secretory epithelial cells in the prostate. it activates several other proteases that may participate in the proteolytic cascade mediating metastasis of cancer. thus, modulation of hk2 activity is a potential way of preventing tumor growth and metastasis. furthermore, specific ligands for hk2 may be potentially useful for targeting and imaging of prostate cancer. we used enzymatically active recombinant hk2 captured by a monoclonal antibody exposing the active site of the enzyme to screen phage display peptide libraries. six different peptides binding to hk2 were identified using libraries expressing 10 or 11 amino acids long linear peptides. three of these peptides were specific and efficient inhibitors of the enzymatic activity of hk2. alanine substitution analysis revealed that motifs of 5-7 amino acid determined the inhibitory activity of the peptides. the peptides are also of potential utility for development of immunopeptidometric assays for hk2, which is promising marker for diagnosis of prostate cancer. furthermore, these peptides are potentially useful for treatment and targeting of prostate cancer. the mechanism of autoactivation of the zymogen masp-2 residues on the surface of pathogens. we managed to recombinantly express and purify two forms of zymogen masp-2. one form is the wild type zymogen enzyme, which can be activated, while the other one is a stable zymogen mutant form of masp-2. we could prepare the zymogen form of wild type masp-2 under certain conditions which enabled us to examine the kinetics of activation. we demonstrated that activation of masp-2 is a true autocatalytic activation without the involvement of any other protease. we characterized the enzymatic properties of zymogen masp-2 using the stable zymogen form. we demonstrated that zymogen masp-2 cannot cleave small synthetic substrates but it can cleave large protein substrate (c4). a molecular model for the interaction between zymogen and activated masp-2 during activation has also been built based on the available 3d structures of zymogen and activated masp-2. influence of streptokinase on the fibrinolytic system proteins the present study is dedicated to the investigation of the effect of protein by bacterial origin -streptokinase (sk) on the activity and interaction regulation mechanisms of fibrinolytic system proteins. the study was carried out with use of porcine haemostasis system which plasminogen isn't activated by sk. especially we were interested in study of the changing fibrinolytic system parameters such as tissue type plasminogen activator (t-pa), plasminogen activator inhibitor (pai-1), plasminogen, a2-antiplasmin activities. also the main parameters of coagulation system such as fibrinogen, soluble fibrin, fibrin degradation products levels and thrombin activity and quantity were studied. it was used affinity chromatography, electrophoresis, western-blotting, elisa, determination of proteins activity. it has been determined an increased consumption of plasminogen on 15% in 4 h after streptokinase injection. it was shown that activity and concentration of t-pa were significantly increased in 3.5 times in 1 h. on the next stages of investigation this parameters tend to norm. after sk injection pai-1 quantity was increased in two times (16.7 ng/ml compared to normal 8.9 ng/ml). the interesting fact was the activation of prothrombin by sk without activation of coagulation system in vivo. the injection of sk causes the significant increase of t-pa activity and quantity possibly due to direct or/and indirect effect on endothelial cells. we can conclude that sk causes pai-1 secretion due to effect on platelets as 90% of pai-1 storage is in a-granules of platelets. thus analysis of the data displayed besides of well-known sk function the influence of sk on the changing of fibrinolytic system potential possibly due to its effect on endothelial cells and platelets. paracrystalline inclusions in the mitochondrial matrix or intermembrane compartment occur in several biochemically unrelated disorders such as myopathies, paragangliomas and steatohepatitis, and in various cell types under normal conditions, as well. however, little is known about the composition of the inclusions, the mechanism of their formation and their relation to disease processes. in this study we have described the helix-shaped structures in the intracristal compartments of rat liver mitochondria that have undergone ca 2+ -induced permeability transition. the filaments are anchored in opposing parts of the mitochondrial membranes and appear to support the cristae mechanically. a protein, that apparently is a component of these helical filaments, has been identified as serine protease lactb. this protein shows close sequence similarity to the class c bacterial beta-lactamases and is the only member of this class in animals. since lactb has not been studied previously we cloned its cdna for expression in e. coli as c-terminal his-tagged fusion protein. lactb underwent proteolytic processing in both e. coli and in isolated mitochondria resulting in several protein fragments. this is likely to be due to autocleavage and may be an activation/maturation process. 2d blue native gel electrophoresis indicated that lactb was part of a >600 kda protein supercomplex. in summary, the presence of the serine protease motive in lactb and its supposed ability to form helical filaments suggest that lactb might function not only as a component of 'mitoskeleton' in maintaining and rearranging the mitochondrial ultrastructure under certain conditions, but also might take part in apoptotic processes. novel psychrophylic trypsin-type protease from serratia proteomaculans proteinase with trypsin specificity from psychrophylic microorganism serratia proteomaculans was partly purified. it was shown that the properties of this enzyme (temperature and ph-stability, efficiency of substrate hydrolysis) correspond with the psychrophylic character. inhibitor analysis and study of substrate specificity indicate that this enzyme is serine trypsin-type protease. at the same time this enzyme is zinc-dependent. proteases of such type were unknown till now. secondary specificity of the studied enzyme differs from the bovine trypsin specificity -this protease hydrolyses the short substrates more efficient. zinc, cadmium (ii) and copper (ii) ions in mmolar concentrations inhibit the enzyme activity. the unusual character of calcium ions influence on substrate hydrolysis and inhibition by the bovine pancreatic trypsin inhibitor (bpti) was registered for the studied enzyme. in vitro by a neutral to basic ph change [2, 3] . the kinetics of the activation process can be followed by stopped flow fluorescence (sff) experiments while the structural features of the transition can be explored by in silico molecular dynamics (md) and targeted molecular dynamics (tmd) [4] simulations. to challenge the activation process, mutants were constructed and studied by sff measurements. subsequently, on these mutants multiple md/tmd simulations were carried out. our results indicate the existence of parallel activation pathways. they demonstrate the absolute necessity of multiple simulations and of proper statistics. they reveal the pros and cons of the tmd method. a simple method for the purification of a novel serine endoprotease from wheat triticum aestivum (cv. giza 164) has been developed. it consists of ion-exchange and gel filtration. the molecular mass of the enzyme was 58 kda by sds/page under reducing conditions and 57 kda by gel filtration on a sepharose 6b column. the enzyme had isoelectric point and ph optimum at 4.2 and 4.5, respectively. the substrate specificity of the enzyme was studied by the use of synthesized and natural substrates, azocasein, azoalbumin, hemoglobin, casein, gelatin and egg albumin. the enzyme appears to prefer azocasein with km 2 mg azocasein/ml. the enzyme had a temperature optimum at 50°c with heat stability up to 40°c. while co 2+ and mg 2+ accelerated the enzyme activity by 54 and 56%, respectively, ca 2+ and ni 2+ had very little effect. the enzyme was strongly inhibited by phenylmethylsulphonyl fluoride (pmsf), but not by the other protease inhibitors, suggesting that the enzyme is a serine protease. from the results it can be concluded from the characterization that the t. aestivum serine protease may be suitable for food processing. in vitro effects of a potent, selective dipeptidyl peptidase ii (dppii) inhibitor in leukocytes and u937-cells. the compound was able to penetrate the cell membrane and proved efficacy without evidence for acute cellular toxicity. there was a dosedependent inhibition of intracellular dppii activity without affecting the dppiv activity (maximal efficacy at 100 nm). these properties enable to differentiate between dppii and dppiv in biological systems and allow further investigation of the physiological function of dppii. in a second step, we have been investigating the involvement of dppii in apoptosis in human leukocytes by using this compound. preliminar results based on annexin v-/pi-staining using up to 1 lm inhibitor in u937-cells and pbmc did not show signs of apoptosis while dppii activity was inhibited for 90%. effect of calcium ions on hydrolysis of peptide substrates of general formula a-(asp/glu) n -lys(arg)-b, catalyzed by enteropeptidase (ec 3.4.21.9), differs depending on substrate type. for specific enteropeptidase substrates (n = 4) calcium ion exhibits the promotion of hydrolysis by the natural two-chain enteropeptidase. hydrolysis of atypical enteropeptidase substrates (n = 1-2) is as a rule less efficient; in addition calcium ion shows in this case the inhibition influence. therefore the regulation of the nondesirable side-hydrolysis during full-length enteropeptidase-catalyzed chimeric proteins processing is possible by means of calcium ions. on the contrary the hydrolysis of substrates of all type (n = 1-4) by enteropeptidase light chain as well as the enzyme containing the truncated heavy chain (466-800 or 784-800 fragments) is inhibited by calcium ions. hydrolysis of the natural enteropeptidase substrate, trypsinogen, is at least two orders of magnitude more efficient than any artificial substrate hydrolysis. we propose that this effect is caused by participation in trypsinogen coordination with enzyme of the addition secondary substrate binding site and/or calcium-binding site; both sites located on the n-terminal half (118-465) of the enteropeptidase heavy chain. one more mechanism of the regulation of the enteropeptidase activity by calcium ion is the unusual calciumdependent autolysis of the enteropeptidase heavy chain leading to the drastic loss of its activity towards trypsinogen. autolysis of enteropeptidase heavy chain and well-known autolysis of trypsin were compared; the second one serves as the natural defense mechanism against the undesirable premature proenzymes activation in pancreas leading to pancreatitis. the corresponding enteropeptidase inactivation in low ca 2+ ion environment might be the component of the same protective mechanism. b3-034p human trypsin 4 selectively cleaves myelin basic protein: is this brain protease involved in the pathomechanism of multiple sclerosis? demyelination, the breakdown of the major membrane protein of the central nervous system, myelin is involved in many neurodegenerative diseases. proteases participating in this process are potential targets of therapy in neurodegenerative diseases. in the present in vitro study the proteolytic actions of calpain, human trypsin 1 and human trypsin 4 (the product of gene prss3) were compared on lipid-bound and free human myelin basic protein as substrates. digestions only with calpain and human trypsin 4 actions may be of some physiological or pathological relevance, since these two are expressed in human brain. the fragments formed were identified by using n-terminal amino acid sequencing and mass spectrometry. the analysis of the degradation products showed that human trypsin 4 of these three proteases cleaved myelin basic protein most specifically. it selectively cleaves the arg80-thr81 and arg98-thr99 peptide bonds in the lipid bound form of human myelin basic protein. based on this information we synthesized region 94-104 of myelin basic protein, peptide ivtprtpppsq that contains the specific trypsin 4 cleavage site arg98-thr99. in vitro studies on the hydrolysis of this synthetic peptide by trypsin 4 confirmed our results with intact myelin basic protein. what lends some biological interest to the above finding is that the major autoantibodies found in patients with multiple sclerosis recognize sequence 80-96 of the protein. our results suggest that human trypsin 4 may be one of the candidate proteases involved in the pathomechanism of multiple sclerosis. enteropeptidase is a heterodimeric serine protease of the intestinal brush border that activates trypsinogen by highly specific cleavage of its activation peptide following the sequence asp-asp-asp-asp-lys. its light chain alone is sufficient for an effective cleavage of fusion proteins with trypsinogen activation peptide analog. human enzyme possesses 10-fold specificity coefficient compare to bovine one, and an explanation of this fact can contribute a lot to the attempts of improving or modulating enzymatic properties. highly pure and active recombinant human enteropeptidase light chain (l-hep) was obtained by renaturation from inclusion bodies expressed in escherichia coli cells and the active l-hep was purified on agarose-linked soybean trypsin inhibitor. enzymatic activity of purified l-hep was studied through the cleavage of the synthetic peptide substrates and several fusion proteins. l-hep associated with soybean trypsin inhibitor slowly and z-lys-sbzl cleavage was inhibited with ki* = 2.3 nm. comparison of l-hep and bovine enteropeptidase inhibition by bovine trypsin inhibitor aprotinin has shown almost an order difference in ki*. ph dependence of the enzyme activity was measured and ph optimum point was found to be 7.54. enteropeptidase light chain amino acid sequence and crystal structure were analyzed for the presence of target regions for mono-and bivalent ions. unlike trypsin with predicted and experimentally proved calcium-binding sites and sodium-activated thrombin, l-hep was predicted to be deprived of any of such sites and an influence of these ions on the cleavage of different substrates was found to be confined primarily to a substrate binding. as a continuation of our efforts to fully elucidate the antisnake venom properties of mucuna pruriens and to further understand the molecular changes that occurred in mouse plasma proteome as a result of in vivo challenge test with venom and mucuna pruriens proteins (mpe), two dimensional polyacrylamide gel electrophoresis was done. plasma was pooled and gels were run in triplicate to eliminate both biological and experimental variations. analysis using imagemaster 2d platinum software and other statistical analysis tools showed significant differences in protein expression between all the treatments and the control group. some proteins were down regulated, some up-regulated, some completely disappeared while new protein spots were identified. the protein expression of plasma of mouse immunized with mpe for 3 weeks before challenge with lethal dose of venom and that injected with venom alone was more complex. some venom proteins like ecarin are serine proteases that activate clotting factors like prothrombin, causing haemorrhage and disseminated intravascular coagulation, on the other hand, the protease inhibitors from mucuna pruriens must have acted to antagonize these effects by direct proteolysis (cleavage products/spots appearing in the protein map) or other immunological mechanisms. the results obtained represents the first proteomics approach in studying all the plasma proteins involved in this phenomenon. we have only concentrated on protein spots showing interesting variations with respect to control. it is also an important step in the identification of the affected proteins, the kind of modifications/molecular mechanisms involved which is likely the basis of the in vivo protection the plant extract showed against the venom. the use of enzymes at low temperatures has great potential in terms of lower energy costs, therapeutic applications and to lower microbial contamination in industrial processes. low temperature proteases (cryophilic -or psycrophilic -proteases) are of particular interest for detergents and as wound debriding agents. at present, we are studying cryophilic proteases from antarctic krill (euphausia superba), which normally lives in the sea at temperatures near 0°c. we have isolated several low temperature proteases by chromatography. enzyme activities and stability were characterized at low temperatures and as a function of ph to find optimum conditions for different applications. a particular enzyme, named kt1, showed particularly high specific activity at 20°c, several times that of commercial preparations of proteases such as subtilisins. this protein showed a high degree of similarity with digestive trypsins isolated from various arthropoda species. using mrna molecules obtained from abdominal sections of e. superba and subsequently subjected to a reverse-transcription reaction, we identified, isolated and sequenced a dna molecule that codes for an inactive zymogen of the enzyme. cloning of this dna sequence in escherichia coli strains allowed the recombinant expression of the zymogen, followed by purification and activation of the zymogen, which lead to an active cryophilic trypsin. we performed a homology modeling procedure that conducted us to obtain a molecular model of the mature enzyme. the 3d model thus obtained was refined using energy minimization, hydrogen network optimization and residue-residue contact optimization techniques, leading to a reliable model of the enzyme. we used this model to identify many interesting and novel features of the enzyme molecule that could be related with its cryophilic character, and to propose site-directed mutagenesis strategies that could be used to improve the enzyme performance at low temperatures, its ph-activity profile, specificity, inactivation resistance and recombinant expression. in addition, the 3d model allowed us to design and experimentally obtain mutants that are resistant to auto-degradation and more readily activated. molecular cloning and expression of lactba mitochondrial serine protease mitochondria are thought to have originated from a symbiotic relationship between a bacterium able to perform aerobic metabolism ant the ancestor of eukaryotic cells. lactb is the only mammalian protein showing sequence similarity to bacterial serine proteases and belongs to c class b-lactamases. mouse lactb is 551 amino acids long and compromises a predicted mitochondrial import sequence, a short putative transmembrane segment, a b-lactamase homology domain containing the serine protease motif, -sxxk-, and a c-terminal d-transpeptidase domain. the physiological role of mammalian lactb is unclear. therefore, the purpose of this research work was to clone the gene of lactb for expression of lactb in e. coli for further biochemical and cell biological study. the full length lactb gene was cloned into the entry plasmid pentr/sd/d-topo. expression clones were created performing a recombination reaction between the entry clone and four destination vectors. expression constructs resulting in n-or c-terminal gst fusion protein and in n-or c-terminal his6-tag fusion protein were transformed into bl21 (de3) competent cells which are designed for use with bacteriophage t7 promoter based expression systems. when lactb was expressed as an n-terminal gst fusion protein, full-length lactb protein was recovered by glutathione-agarose affinity chromatography. expression of lactb as a c-terminal gst fusion protein or with either an n-or c-terminal his6-tag resulted in proteolytic degradation of the protein and we were not able to detect full-length lactb. these results show that the n-terminal gst fragment protects lactb from proteolytic processing and that lactb can undergo autoproteolysis, which may be a part of a physiological maturation or activation process. design and synthesis of retro-binding peptides active site inhibitors of thrombin thrombin is an important pharmaceutical target for the treatment and prevention arterial and venous thrombosis. biological active peptides are recognized to have significant therapevtic potential but serious limitations especially for oral dosing. the peptide stereomers could differ when forming productive complexes with an enzyme. moreover, the replacement of l-amino acid residues forming the hydrolyzed p1-p'1 bond by their enantiomers is known to result in either an uncleavable or a very slowly hydrolyzed analogue. this phenomenon is often used for the synthesis of the peptide's inhibitors stable to the degradation by the enzymes of organism. as the peptides containing d-amino acids, nor are subject to an enzymatic hydrolysis, the purpose of researches was synthesis of a retro -d-analogues of thrombin's substrates constructed from d-amino acids. the di-and tripeptides of the general formula x-d-arg-d-phe-ome [where x = z, tos, ac h, and z-d-arg-d-ala-(d), l-phe-ome (otbu)] were synthesized by conventional methods of peptide synthesis in solution. special features of their interaction with thrombin are investigated. their inhibitory action on reaction of splitting of fibrinogen by thrombin and on reaction of a hydrolysis by thrombin baee showed, that their inactivating action depends on the substituent on n-end of dipeptides and configuration of phenylalanine in a molecule of tripeptides. the relationship between structure and inhibitory action of the synthesized peptides is discussed. the successful application of d-amino acids for designing of biologically active peptide's analogues as a potential medicinal agent, steady to enzymatic degradation is shown. substrate specificity of mannose lectin binding associated serine proteinase 3 n. s. quinsey and r. n. pike department of biochemistry and molecular biology, monash university, melbourne, victoria australia. e-mail: noelene.quinsey@med.monash.edu.au the innate complement system is involved with the neutralization of pathogenic microorganisms. it plays a comparative role to that of the classic immune complement cascade. in the innate complement system, the oligomers of mannose lectins are able to bind to microorganisms. these oligomers have been shown to have mannose lectin binding serine proteinase (masps) attached, which once activated lead to the activation of the c3 convertase complex, which finally leads to the formation of the membrane attack complex. there have been three active masps identified in the human innate immune system-masp-1, masp-2 and masp-3. there is high homology between these three serine proteases especially in the n-terserpins are protease inhibitors that present their reactive site loop (rsl) to target proteases, followed by drastic conformational changes that inactivate the protease. the sequence of the rsl of serpins determines the target specificity. the drosophila melanogaster gene spn4 encodes multiple serpin isoforms each containing an individual rsl, thus enabling the attack of different proteases. variant spn4a contains a consensus recognition/cleavage sequence of furin within its rsl and is equipped with a signal peptide and an endoplasmic reticulum (er) retrieval signal (hdel). this suggested that the protein resides in the secretory pathway, like furin, a proprotein convertase that activates many cellular proteins and pathogens. our experiments demonstrate that spn4a forms sds-stable complexes with human furin that is inhibited with a second order rate constant of 5.5 · 10 6 /m/s. the rsl of spn4a is cleaved c-terminally to arg-arg-lys-arg, in accord with the enzyme's cleavage site. furthermore, the serpin is retained in the er of transfected cos7 cells as shown by immunofluorescence staining. a hdel deletion mutant was detected mainly in the medium of trans-fected cos7 cells, demonstrating the necessity of the hdel signal for the observed cellular localization. further experiments show that furin 1 and 2 of drosophila melanogaster are physiological targets for spn4a, since secreted forms of both enzymes form stable complexes with the serpin. together, the results demonstrate that spn4a is a potent inhibitor of furin that may meet the target at its natural location. experiments with the other rsl variants show that the spn4 gene represents a multipurpose weapon that is directed against different families of proteases. formation of the covalent tetrahedral complex (tc) with substrate is the first step of the catalytic process in the active site of serine proteases. his57 (chymotrypsin numbering) plays a role of a general base catalyst, activating the ser195 nucleophile by abstraction of its proton. it was experimentally observed that the pka of his57 ne in tc formed by serine proteases with transition state analog inhibitors is about 5 units higher than the corresponding pka in the free enzyme. this work demonstrates that the environmental change of the his57 in tc, induced by the substrate binding in the enzyme active site, is the dominant factor in the pka increase of his57 ne, and triggers the enzymatic processing of the substrate. these results are based on quantum mechanical modeling of the active site of free chymotrypsin and tc complex of chymotrypsin with trifluoromethyl ketone inhibitor in dft b3lyp/6-31+g** level of theory. the polar environment of the enzyme active site is accounted for explicitly in the microscopic model. the combined environmental effects of the bulk water solvation and the rest of the protein is implicitly accounted for by our scrf(vs) continuous solvation approach. the role of local polar effects, such as the oxyanion and the asp102-his57 hydrogen bond, on the pka of his57 ne in tc is analyzed. genome-wide analysis of subtilase (subtilisinlike serine protease) genes in microbial genomes limited to regions surrounding the asp, his and ser catalytic residues. pattern-searching methods using hidden markov models, based on conserved sequences surrounding the catalytic residues, were used to search for subtilases encoded in >200 bacterial and archaeal genomes, representing 177 species. more than 350 subtilases were found to be encoded in 109 genomes. subtilases are more commonly found in grampositive bacteria than in archaea or gram-negative bacteria, and it is more common to have multiple subtilase-encoding genes than a single gene. the majority of the subtilases have a predicted signal peptide for translocation across the cell membrane, and a sub-group of these secreted subtilases are predicted to have a carboxy-terminal cell-envelope anchor, mainly of the lpxtg type for covalent anchoring to peptidoglycan. the genomic context of the subtilase-encoding genes was analyzed to gain insight in putative functions for these proteolytic enzymes. by also taking into account the predicted intracellular or extracellular location of the encoded subtilases, it was possible to predict a function for many subtilases in either nutrition/growth, spore germination, surface protein processing/activation, bacteriocin/toxin processing, or sigma factor activation/regulation. the poisoning by botropics species makes a similar physiologic, one of systemic effects is the blood coagulation for several mechanisms, as direct action on fibrinogen; factor x activation or platelet activation, by toxins of venoms. in the last years were identifies in botropics venoms, serine proteases. this toxins are responsible by coagulant activity with direct action on fibrinogen. serine proteases are utility for hemostatic system studies and for therapeutics use. looking for new molecules models is very important to show the mechanism of action and search structural characteristics responsible for its activities. the present work has the objective of purification and characterization of a coagulant factor (cf) from b. pirajai venom. the purification was made using a gel filtration, hydrophobic chromatography and an affinity chromatography. the molecular filtration was made in sephadex g-75 with ammonium bicarbonate buffer (ambic) 0.05 m ph 8.1, resulting four fractions (p1-p4), the coagulant fraction was named p1. the p1 fraction was submitted in phenyl sepharose chromatography using triz buffer 10 mm ph 8.6 in a decreasing gradient of nacl (4; 3; 2; 1; 0.5; 0 m), and to finish the chromatography it was used distilled water, resulting six subfractions (fp1-fp6), the coagulant subfraction was named fp1. the fp1 sub fraction was submitted in benzamidine sepharose chromatography and eluted in the solutions: distilled water, obtained the subfraction bfp1, sodium phosphate buffer 20 mm ph 7.8, obtained the subfraction bfp2 and glycine buffer 20 mm ph 3.2, obtained the sub fraction bfp3 that is the cf. the cf displayed one band in sds-page (11%) showing a pure protein, it has 58 kda, the minim coagulant dose is 1.75 lg and has action on fibrinogen beta chain. the genome of arabidopis thaliana encodes 16 putative proteases from the deg/htra family. this group of atp-independent serine-proteases was well examined in other organisms, especially e. coli and humans, but only limited data is available for members from this protease family in plants. deg1 and deg2 have been shown to act as proteases in the chloroplast, but no deg/htra proteases from other compartments have been examined so far. the putative protease deg15 is predicted to be localized in the peroxisome. we cloned the gene encoding deg15 (at1g28320) in an overexpression vector for heterologous expression in e. coli. the tagged protein was purified by affinity chromatography and used to raise polyclonal antibodies. with these antibodies we investigated the intracellular localization of deg15 and the protein level under various stress conditions in order to evaluate the in planta function of this protein. the effect of site-directed mutagenesis on cold adaptation of vpr; a subtilisin-like serine proteinase from a psychrophilic vibrio-species psychrophilic enzymes have very similar 3d structures as their homologous enzymes from mesophilic and thermophilic organisms. main characteristics of enzymes from psychrophiles are their high catalytic efficiency (kcat/km values) and thermolability. a subtilisin-like serine proteinase from a psychrophilic vibrio-species (vpr) shows these characteristics when compared to homologous enzymes from mesophilic and thermophilic organisms. the vpr gene was cloned, sequenced and expressed in e. coli and recently the crystal structure was determined at 1.84 å resolution [1] . structural comparisons have been carried out which have led to hypotheses about some of the structural factors which may contribute to cold adaptation of vpr. some of these hypotheses have been examined using site-directed mutagenesis. the specific residue exchanges were selected with the objective to incorporate stabilizing interactions into the cold adapted enzyme which were deemed to be present in related thermostable homologues. these include incorporation of pro into loops, a new potential salt-bridge, as well as substitutions aimed at improving packing in the hydrophobic core and decreasing apolar exposed surface. we have also introduced ser to ala substitutions at three different locations in the cold-adapted enzyme, but these were the most frequent amino acid exchanges observed in sequence comparisons of the enzyme to those of more thermostable homologues. here we report on the catalytic and stability characteristics of the selected mutants. engineering of gfp for the screening of serine protease inhibitors site specific proteolysis has been an attractive target for the development of antiviral therapies based on selective viral inhibitors. it has been previously demonstrated that reporter proteins like beta-galactosidase could be very useful for the high-throughput screening of hiv-1 protease inhibitors through the display of an accessible protease target site on the enzyme surface. in this work, by using structural analysis, we have engineered the gfp protein from jellyfish aequorea victoria to accommodate in its surface the hcv virus ns5a-5b protease cleavage site edvvccsmsytwtg, in a manner that proper proteolysis results in a fluorescent activity decrease. the three resulting gfp constructions, carrying the protease cleavage site in positions 23-24, 102-103 and 172-173, were soluble expressed in escherchia coli. moreover, the hcv ns4 cofactor residues 21-34 fused in frame via a short linker to the amino terminus of the hcv ns3 protease domain (residues 2-181) were also expressed in e. coli and under 1mm iptg induction, at least 60% of soluble protein was recovered and further purificated by an histidin tag. the analysis of gfp proteolysis in front of hcv recombinant protease were performed either with bacteria crude extracts and purificated proteins. the results presented here indicated that proper solvent exposure of target sites on gfp carrier protein may be a critical factor for protease cleavage and for the observation of fluorescence activity variance, being an aspect of absolute relevance for further design and implementation of newer analytical tests. various kinds of stressors cause the group of metabolic changes defined as the general stress response, initiated by some intracellular signals, such as production of abnormal or denaturated proteins, enhanced generation of reactive oxygen species and others. proteolytic enzymes quickly modify proteins and as a consequence can regulate cellular metabolism. although the stress defense mechanisms have been very often described in the recent literature, in very few works were estimated stress response abilities of white-rot basidiomycetes, which produce two kinds of very important ligninolytic enzymes -laccase and peroxidases. our previous results showed that the addition of menadione to abortiporus biennis idiophasic cultures caused the significant increase of the extracellular laccase activity in comparison to the control. the aim of this study was to determine activities of serine proteinases and natural serine proteinase inhibitors in idiophasic cultures of basidiomycete a. biennis grown under menadione-mediated oxidative stress conditions. we investigated the changes of intracellular serine proteinases activities in the presence and absence of atp, using hemoglobin and fluorogenic substrates. the level of natural serine proteinase inhibitors in mycelia was also measured. a fungal inhibitor of trypsin was partially purified and used to in vitro experiments. an interesting correlations between serine proteinases, serine proteinase inhibitors and laccase activities in prooxidant treated cultures were also observed. it can suggest that the proteolytic modifications under oxidative stress conditions can act as a regulation way of laccase activity. serine proteinases, inhibitory and laccase activities were additionally analyzed by native page. calpain is a ca 2+ -regulated cytosolic cysteine protease, functioning as a ''modulator protease'', i.e. regulating/modifying functions/activities of substrates by limited proteolysis to modulate cellular functions. human has 14 calpain genes and potential substrates extend to various cytosolic proteins such as kinases, transcription factors, cytoskeletal and er proteins. in skeletal muscles, expression of p94 (also called calpain 3) predominates, playing an indispensable role for muscle functions in cooperation with ubiquitously expressed conventional calpains. for, a defect of p94 proteolytic activity originated from gene mutations causes muscular dystrophy. p94 localizes in myofibrils binding to connectin/titin, a gigantic elastic muscle protein connecting the z-and m-lines of sarcomere, the repetitive unit of myofibril, with a single molecule. in mdm (muscular dystrophy with myositis) mice, connectin/titin with a small deletion caused by natural mutation of the connectin/titin gene is expressed, resulting in severe muscular dystrophy phenotypes such as body weight less than a half of that of wild type, severely affected limb muscles with impaired walking ability and only 2-3 months of life time. the deletion in the mdm allele of the connectin/titin gene overlaps one of the binding sites of p94 in the n2-line, another electron-microscopically visible line between the z-and m-lines of sarcomere. the mdm phenotypes clearly indicate that connectin/ titin or p94 or both are essential for proper muscle functions. to elucidate physiological roles of connectin/titin and p94, we analyzed mdm mice in relation to calpain system. as a result, mar-ps (muscle ankyrin repeat proteins) were shown to be up-regulated in mdm muscle. marps bind to the n2-and z-line regions of connectin/titin and function as transcriptional regulators translocating into the nuclei. carp (cardiac ankyrin repeat protein), one of marps, binding site in the n2-line region is proximate to the p94 binding site, thus suggesting interactions of both molecules. possible signal transduction systems to modulate muscle functions revealed by the analyses will be discussed based on the results. inhibition and activation of calpain by its disordered endogenous inhibitor, calpastatin p. tompa 1 , z. mucsi 2 , o. gyo¨rgy 2 , c. sza´sz 1 and p. friedrich 1 1 institute of enzymology, biological research center, budapest, hungary, 2 research group of peptide chemistry, university of eo¨tvo¨s lora´nd, budapest, hungary. e-mail: tompa@enzim.hu calpains are a family of intracellular calcium-activated cysteine proteinases, implicated in the regulation of key cellular processes, such as cell division and programmed cell death. their activity is under tight control by an intracellular protein inhibitor, calpastatin, an intrinsically unstructured protein that contains four equivalent inhibitory domains. each of these comprise three conserved subdomains, of which subdmomains a and c anchor the inhibitor in a calcium-dependent manner, whereas subdomain b binds at the active site and inhibits the enzyme. in this work it is shown that the consequence of this mode of binding is that isolated a and c peptides promote calcium binding to calpain and thus activate the enzyme. this activation is manifest in the sensitization to calcium ion: the calcium required for half-maximal activity is lowered from 4.3 to 2.4 lm for l-calpain and 250 to 140 lm for mcalpain. in the physiologically significant sub-micromolar and low micromolar calcium concentration range this sensitization leads to a more than tenfold activation, which is of potential physiological importance as isolated calpain requires high calcium concentrations never realized in vivo. here we suggest calpastatin is degraded in vivo in a way that generates the activator peptides. due to the structural disorder of calpastatin, this unprecedented mode of action raises intriguing questions with respect to the generality of this ambivalent behavior. to address this issue, we have collected extreme cases, when the same protein elicits opposing, inhibitory and activatory, responses within the same molecular setting: structural predictions show that these proteins are largely disordered. as a conclusion, the possible general implications of this finding are discussed. meprins are oligomeric, brush border membrane or secreted zinc proteases that have unique and complex structures. they are composed of multidomain, highly glycosylated evolutionarily-related a and b subunits that form disulfide-linked homo-or heterooligomeric dimers. the homooligomeric form of meprin a forms very high molecular mass multimers of 1 000 000-6 000 000 da, among the largest extracellular proteolytic complexes known. meprins cleave cytokines, growth factors, bioactive peptides and extracellular matrix proteins, important compounds in inflammatory intestinal disease and in cancer metastases. to investigate the role of meprins in intestinal immune responses, inflammation was induced in mice by oral administration of dextran sulfate sodium (dss). the results showed that wild-type mice (c57bl/6 · 129) had a more severe reaction to dss than meprin b null mice on the same genetic background, as determined by body weight loss, intestinal bleeding and mortality. this implies that the presence of meprin b increases host damage caused by dss and that meprin b plays an active role in intestinal pathophysiology. meprins are also expressed in colon cancer cells (e.g. sw480, sw620, and caco-2). expression of meprin a appears to increase with increasing metastatic potential. in addition, meprin a is highly expressed in the human liver hepatoblastoma cell line hepg2 and abundantly secreted into culture media. examination of human tumor samples showed that meprin a is expressed in primary colon tumors and in tumors that have metastasized to the liver. this indicates that meprin a expression in gastrointestinal tumor cells contributes to the progression of the disease. biochemical pathways mediating necrotic cell death and neurodegeneration in caenorhabditis elegans n. tavernarakis, p. syntichaki, c. samara and k. troulinaki institute of molecular biology and biotechnology, foundation for research and technology, heraklion, crete greece. e-mail: tavernarakis@imbb.forth.gr necrotic cell death plays a central role in devastating human pathologies such as stroke and neurodegenerative diseases. elucidation of the molecular events that transpire during necrotic cell death in simple animal models should provide insights into the basic biology of inappropriate neuronal death, and facilitate the characterization of mechanisms underlying degeneration in numerous human disorders. various cellular insults, including hyperactivation of ion channels, expression of human beta-amyloid protein implicated in alzheimer's disease, constitutive activation of certain g proteins, hypoxia and possibly the ageing process, can trigger a degenerative, necrotic cell death in the nematode caenorhabditis elegans. we are genetically and molecularly deciphering the c. elegans necrotic death program. we have isolated mutations in several distinct genetic loci that bock degenerative cell death initiated by various genetic and environmental insults. by characterizing such suppressors, we have discovered that neuronal degeneration inflicted by various genetic lesions in c. elegans, requires the activity of specific calcium-regulated calpain proteases and acidic ph-dependent aspartyl proteases. although, it is believed that these proteases become activated under conditions that inflict necrotic cell death, the factors that govern the erroneous activation of such-otherwise benign-enzymes are largely unknown. we identified novel factors that modulate cellular ph homeostasis, which are required for necrosis and showed that targeting these factors effectively protects from necrotic cell death in c. elegans. our findings demonstrate that two distinct classes of proteases are involved in necrotic cell death and suggest that perturbation of intracellular calcium levels may initiate neuronal degeneration by compromising ph homeostasis and deregulating proteolysis. search for regulatory proteins which are controlled by proteolysis in escherichia coli based on microarray analysis j. m. heuveling ag hengge, institute of microbiology, fu berlin, berlin, germany. e-mail: joheuvel@zedat.fu-berlin.de the impact of controlled proteolysis on regulatory events in prokaryotes is increasingly recognized over the last decade. as in eukaryotic cells, proteolysis is more than just a garbage disposal but has been found to be implicated in the regulation of many vital functions of the bacterial cells, like cell cycle, stress responses and development (hengge r and bukau b. mol microbiol 2003) . conditional degradation of regulators shows a high potential of integrating a great variety of signals as is well studied for the degradation of sigma s. this sigma subunit of the rna polymerase, which triggers the general stress response in escherichia coli is digested rapidly by the clpxp protease in association with the phosphorylated response regulator rssb under non-stress conditions (stuedemann a. embo 2004). several other regulatory proteins have been found to be subjected to proteolysis, as lexa, a regulator of the sos response. also lon protease is involved for example in the degradation of rcsa, a regulator of the capsule biosynthesis and of sula, a cell division inhibitor (as a review: hengge-aronis r, jenal u. curr opin microbiol 2003). in order to find other regulatory processes in which proteolysis plays a role we pursued a global approach using the microarray technique. in mutants lacking functional clpp or lon proteases or either one of the clp recognition factors clpa and clpx, we searched for genes, which are differentially transcribed compared to the wildtype. we found some interesting groups of genes belonging to common regulons governed by known regulators -candidates for clp or lon mediated proteolysis. after confirmation of these results through lacz fusion studies of representative genes of these regulons, these regulators are presently examined in in vivo degradation studies using immunodetection methods. a distinct group of serine peptidases cannot hydrolyze proteins, but can readily cleave peptides that are up to about 30 amino acid residues long. the representative member of the family, prolyl oligopeptidase is implicated in a variety of disorders of the central nervous system. the enzyme consists of a peptidase domain with an a/b-hydrolase fold and its catalytic triad is covered by the central tunnel of a seven-bladed b-propeller. this domain makes the enzyme an oligopeptidase by excluding large structured peptides from the active site. in most propeller domains the circular structure is ''velcroed'' together in a mixed blade, where both amino and carboxy terminus are involved to form a four stranded antiparallel b-sheet. non-velcroed or ''open topology'' propellers are rare, and prolyl oligopeptidase was the first protein structure exhibiting a domain of this nature. the apparently rigid crystal structure does not explain how the substrate can approach the catalytic groups. two possibilities of substrate access were investigated: either blades 1 and 7 of the propeller domain move apart or the peptidase and/or propeller domains move to create an entry site at the domain interface. engineering disulfide bridges to the expected oscillating structures prevented such movements, which destroyed the catalytic activity and precluded substrate binding. this indicated that concerted movements of the propeller and the peptidase domains are essential for the enzyme action. biochemical characterization of thermoplasma volcanium recombinant 20s proteasome and its regulatory subunit g. baydar and s. kocabiyik molecular genetics, biological sciences, middle east technical university, ankara, turkey. e-mail: gozde_baydar@hotmail.com proteasome associated energy dependent proteolysis is not only involved in rapid turnover of specific proteins that could be important during periods of stress, but also engaged in the turnover of the short-lived proteins that regulate a variety of cellular processes in both procaryotic and eucaryotic cell. the universal distribution of proteasome homologs in archaeal genome provide insight into the vital role of archaeal proteasomes. 20s catalytic core of archaeal proteasomes in combination with various aaa atpases and membrane associated lon proteases may play role in stress response or turnover of the regulatory proteins. however, little is known about the potential physiological roles of archaeal proteasomes. this study presents the data on biochemical and biophysical features of recombinant 20s proteasome of a thermoacidophilic archaeon thermoplasma volcanium (tpv). pcr was performed to amplify dna fragments containing tpv genes encoding the a -and b-subunits of the proteasome from tpv genomic dna. the amplified a-gene (tpva) and b-gene (tpvb) together with their upstream sequences were separately cloned and then combined in puc18 vector. the resulting recombinant puc-skba plasmid was used for heterologous production of in vivo assembled 20s proteasome in e. coli. the recombinant proteasome was purified by combination of ammonium sulfate precipitation, gel filtration chromatography (sepharyl s-300) and ion-exchange chromatography (q sepharose). molecular masses of purified protein subunits were estimated as 23.71 kda (b-subunit) and 21.13 kda (a-subunit). substantial post-glutamyl peptide hydrolyzing activity and chymotrysin-like activity were detected as associated with recombinant proteasome. maximum chymotrypsin-like activity was measured at 85°c and ph 8.5. crystallographic studies of the gtp-dependent transcriptional regulator cody from bacillus subtilis. cody is a gtp dependent transcriptional regulator of early stationary phase and sporulation genes in bacillus subtilis. it is activated by gtp, during rapid cell growth it represses several genes whose products allow adaptation to nutrient depletion. when the cells pass from rapid growth to stationary phase, the intracellular concentration of gtp drops thus releasing the repressed genes. cod y is a 259-residue polypeptide containing a helix-turn-helix motif for binding to dna. it also has motifs common with small gtpases, but cody has a much lower affinity for gtp. crystals of the full-length cody have been grown in the presence and absence of gtp from sodium citrate buffered solutions using lithium sulphate as a precipitant and diffraction data have been collected to 3.5 å resolution. attempts to solve the structure using anomalous data from the semet derivative crystals of cody have been hampered by the large number (70) of methionines in the asymmetric unit and difficulties in reproducibility of angiotensin-converting enzyme (ace) is a zinc metallopeptidase critical for the generation of the vasoconstrictor peptide angiotensin ii. a homologue of ace, ace-2, has recently been identified, which appears to play a counter-regulatory role to ace by inactivating angiotensin ii. like ace, ace-2 is a type i membrane protein with its active site contained within the extracellular domain. the expression of ace2 protein is normally low and restricted primarily to endothelial cells of the heart and kidney, kidney epithelium and testis. recent evidence from ourselves and others indicates that ace2 is significantly upregulated in a number of pathologies, such as myocardial infarction, renal disease and hepatitis c-induced cirrhosis. given that ace can be proteolytically released from the cell surface in culture, ace2 may likewise be shed into plasma or urine. detection of elevated levels of ace2 in plasma and urine may be a useful biomarker for the diagnosis of hepatic, renal and vascular disease. using a specific quenched fluorescent substrate, we have detected ace2 activity in human urine. in contrast, ace2 activity could not be detected in human plasma; interestingly, however, we noted that plasma markedly inhibited the activity of recombinant ace2, thus compromising the possibility of measuring plasma enzyme activity. we are in the process of purifying this inhibitor, which preliminary results suggest is small and hydrophilic. we are also currently optimizing methods for its removal from plasma samples, thus allowing detection of low levels of soluble ace2 activity in normal human plasma. the identification of a potential endogenous inhibitor of ace2, the first for this family of metallopeptidases, could have significant consequences for ace2 function in vivo and the regulation of angiotensin peptides. future studies will examine whether plasma or urinary levels of ace2 are elevated in cardiovascular, renal or liver disease. molecular determinants of proteolytic processing of non-structural polyprotein of semliki forest virus. institute of molecular and cell biology, university of tartu, tartu, estonia. e-mail: lulla@ut.ee semliki forest virus (sfv) is a positive-stranded rna virus. the replication of sfv is performed by the rna-dependent rna replicase complex (rc) and regulated by proteolytic processing. during the course of the infection template preference of rc changes from rna plus-strand to minus-strand. it has been known for several years that this preference switch is due to the proteolytic processing of sfv non-structural polyprotein p1234, mediated by viral cysteine protease located in the carboxy-terminal domain of the nsp2 protein. tight temporal regulation of this template specificity switch is crucial for the viral replication, but, nevertheless, its mechanism remains unsolved. therefore, the mapping of the essential molecular determinants of the site-specific cleavage consensuses may provide necessary information, concerning the cleavage regulation as well as regulation of the rna replication. the results of our studies indicate that as little as 5 amino acid residues from the c terminus of nsp3 protein determine the specificity of the proteolytic cleavage of the nsp3/nsp4 junction. at the same time sequences laying downstream of the cleavage point (in nsp4 region) have only minor effect on the cleavage efficiency. the exact region required for the cleavage of nsp2/nsp3 junction is yet not known but the sequences, required from c-terminal part of nsp2 protein, are likely short as well. in contrast, sequence lying within 80-240 n-terminal amino acid residues of nsp3 is vital for cleavage of the nsp2/nsp3 junction. this region may represent the cofactor of the nsp2 protease that activates processing at the nsp2/nsp3 cleavage site. thus, as the result of current research, a principally new function -regulation of the proteolytic processing and rna replication -was mapped to the conserved n-terminal region of the nsp3. this finding significantly improves our understanding about the role of nsp3, which was enigmatic till now, in the virus life cycle. activation occurs within the specific dibasic motif hsiirrsl, suggesting the involvement of the proprotein convertases (pcs) in these process. this family of endoproteases are responsible for the activation of a large variety of regulatory proteins by cleavage at multi-basic recognition sites exhibiting the general motif (k/r)-(x)n-(k/r)(n = 0, 2, 4 or 6). cotransfection of the furindeficient colon carcinoma cell line lovo with provegf-c and different pc members revealed that furin, pc5 and pc7 are vegf-c convertases. the processing of provegf-c is blocked by the inhibitory prosegments of furin, pc5 and pace4, as well as by furin-motif variants of alpha2-macroglobulin and alpha1antitrypsin. accordingly, mutation of the vegf-c pc-site (hsiirrsl to hsiisssl) inhibited provegf-c processing. following zebrafish caudal fin amputation, the injection of control vector or vector containing wild vegf-c did not affect fin regeneration. in contrast, injection of muted vegf-c (pro-vegf-c) inhibited fin regeneration. these data highlight the importance of vegf-c processing in zebrafish fin regeneration and suggest that zebrafish can be used as a simple and useful model for studying the role of protein maturation by the pcs in physiological processes. thimet oligopeptidase (top) hydrolyzes a variety of bioactive peptides and is implicated in the regulation of neurological and other physiological processes. top is composed of two ''clamshell'' domains, with the substrate-binding pocket and catalytic site lying between these domains. it is speculated that conformational changes in loops and coil regions connecting the domains lead to changes in substrate specificity. the loop region (residues 599-611) is close enough to the active site to interact with even the smallest substrate. it contains three glycine residues and is expected to be quite flexible. in an effort to trap intermediate conformations of the loop, we have replaced gly 599, 603, or 604 with ala and have compared the activities of the three resulting protein constructs towards two quenched fluorescent substrates. all three enzymes had lower activity than wild type towards a bradykinin analog, with g599a, the most active of the mutants, possessing 1/3 wild-type activity. however, utilizing a smaller substrate, g603a was the most active, surpassing even wild type (fivefold increase in activity). g604a had little activity towards either substrate. these results are consistent with data that revealed increases in activity towards the larger substrate, when the enzyme is partially denatured and presumably, more flexible and with increased accessibility of the binding loop to proteolytic enzymes, when partially denatured. acknowledgment: this work was supported by hhmi, nih-ns39892 (mjg). the proteasome: paradigm of a self-compartmentalizing protease self-processing of subunits of the proteasome crystal structures of the rhodococcus proteasome with and without its pro-peptides: implications for the role of the pro-peptide in proteasome assembly handbook of metalloproteins bovine chymotrypsinogen-a x-ray crystal-structure analysis and refinement of a new crystal form at 1.8 a resolution equilibrium and rate constants for the interconversion of two conformations of a-chymotrypsin. the existence of a catalytically inactive conformation at neutral ph refolding transition of alpha-chymotrypsin -ph and salt dependence e-mail: saleh38@hotmail.com reference 1. arnorsdottir j, kristjansson mm, ficner r. crystal structure of a subtilisin-like serine proteinase from a psychrotrophic vibrio species reveals structural aspects of cold adaptation (which is an excellent substrate for adam-17), we observed 35% increase in enzymatic activity in the media of 1 mm 5-ht-treated cells compared to untreated cells. however, we did not see any increase in the fluorescence when we used ''cate1'', an adam substrate, which does not recognize adam-17. to further support a role for adam-17/tace, we designed silencing rnas against the enzyme, which were introduced into the mesangial cells using lentiviral infection. successful silencing was confirmed by western blotting 4 days after infection. control and tace silenced human mesangial cells were stimulated with 2-10 lm of serotonin for 5 min, and erk activation was assessed by western blotting baron-ruppert 2 and e. heymann 1 1 department of physiological chemistry (fb8/gw) e-mail: rebecca.lew@med.monash.edu.au b4-015p functional properties of p94/calpain3 and connectin/titin in mdm mouse skeletal muscle y bunkyo-ku the lectin pathway of complement system is an important component of the innate immunity. it provides the first line of defence against infection, since it is activated on the surface of invading pathogens. the activation of the complement system results in the destruction and clearance of foreign microorganisms. mannose-binding lectin-associated serine protease-2 (masp-2) is the enzyme which is responsible for the initiation of the lectin pathway of complement activation. masp-2 is a multidomain serine protease, which is synthesized as an inactive zymogen and become activated upon mbl binds to carbohydrate plant proteinase inhibitors are widely spread in the different plant species being a significant component of a defense system. somewhere a significant diversity of the proteins related to the same structural family of the inhibitors in the same species may be observed. the family of potato kunitz-type proteinase inhibitors (pkpis) exemplifies a group of proteins with the diverse properties and may be divided into three major homology groups: a, b and c. a lot of genes encoding different pkpiproteins of each group were found in various potato cultivars (solanum tuberosum l.). inhibition activity of plant invertase, cysteine and serine proteinase was found in proteins subgroup c. a set of gene copies were isolated by pcr from potato cv. istrinskii genome. dna sequencing analysis of these resulted in identification of 24 different dna sequences with a high similarity to potato kunitz-type inhibitors of group c (pkpi-c). cluster analysis demonstrated that this clones represented multiple copies of six new genes denoted as pkpi-c1, -c2, -c3, -c4, -c5 and c6. it can be supposed that at least two alleles containing pkpi-c genes are harbored in tetraploid genome of potato. one of new genes, namely pkpi-c5, exhibited 99% identity with known invertase inhibitor cdna (1423) from cv. provita. another pkpi-c6 gene was similar (98% identical residues) with cdna (p340) from potato cv. bintje encoding for a putative trypsine inhibitor. four other new genes demonstrated as much as 89-92% identity with known pkpi-c proteins from other potato cultivars. the n-terminal sequence of the protein encoded by the pkpi-c2 gene was identical to the n-terminal sequence of specific subtilisin inhibitor pksi isolated from cv. istrinskii.b3-049p regional distribution of human trypsinogen 4 in human brain determined at mrna and protein level j. to´th 1 , l. gombos 1 , e. siklo´di 1 , p. ne´meth 2 , m. palkovits 3 , l. szila´gyi 1 and l. gra´f 1 1 laboratory of enzymology, department of biochemistry, eo¨tvo¨s lora´nd university, budapest, hungary, 2 institute of immunology and biotechnology, university of pe´cs, pe´cs, hungary, 3 laboratory of neuromorphology, department of anatomy, semmelweis university, budapest, hungary. e-mail: july@ludens.elte.huproteases play an important role in many physiological and pathological processes in the central nervous system such as development, neurite outgrowth, neuronal plasticity and degeneration and cell signaling. a gene coding for such an enzyme might be prss3 on chromosome 9 of the human genome. it encodes due to alternative splicing both mesotrypsinogen, which is expressed in pancreas, and trypsinogen 4 whose mrna has been identified in different human tissues (initially in brain, recently in different epithelial cell lines from prostate, colon and airway). analysis of the gene prss3 predicted two isoforms of the zymogen: isoform a may have a 72 amino acid, while isoform b a 28 amino acid n-terminal leader sequence. in order to gain information on the possible role of human trypsinogen 4 we have determined its amount at the mrna and the protein level as well in 17 selected brain areas using real-time quantitative pcr and elisa.the highest transcript levels could be detected in cerebellar cortex, while low amounts were found, e.g. in cerebellar white matter samples. the distribution of the mrna in different brain areas measured by real-time pcr is consistent with the protein levels detected with elisa. the usage of different monoclonal antibodies specific for the 28 amino acid leader sequence and the protease domain allowed the separate detection of the zymogen and the active enzyme. in e.g. the hypothalamus the zymogen is the dominant form, while a significant degree of activation was found in the cerebellar cortex. our data indicate that the extent of activation varies with different areas. as human trypsinogen 4 is ubiquitous in the brain we conclude that it might play a role in general neurological processes. serine proteases are enzyme involved in the maintenance of the cell homeostasis. thus, this type of enzymes must be extremely regulated and it has been highly reported that serine proteases are involved in the growth and expansion of different cancers. in this regard, the type ii transmembrane serine proteases (ttsps) constitute a subfamily of membrane anchored serine proteases that are ideally positioned to carry out different interactions with other cell surface or extracellular proteins. among them, tmprss2 and tmprss3 proteins have been reported to be overexpressed in most prostate and ovarian cancers respectively, matriptase/mt-sp1 is expressed in a wide variety of benign and malignant tumors and hepsin is overexpressed in ovarian and renal cancers. desc-1 is a ttsp member found differentially expressed in squamous cell carcinoma (differentially expressed in squamous cell carcinoma gene 1) and differentially from other ttsps, its expression is found to be reduced in tumor tissues respecting to the normal tissue at rna level in head and neck squamous cell carcinoma (hnscc), what suggests a possible tumor protective function for desc-1. in order to shed light about the role of desc-1 in these processes, we have carried out the molecular cloning of the human full-length cdna and expression of the recombinant protein to delineate the implication of this protease in hnscc.diffracting crystals. therefore we used limited proteolysis and mass-spectrometry analysis to identify the domain boundaries of the protein and were able to determine the sequence of two principal proteolytic fragments corresponding to the n-and c-terminal domains of cody. these individual domains which were successfully cloned in escherichia coli, overexpressed as histagged proteins, isolated and purified. both domains have been crystallized. the crystals of the n-terminal domain grow from bis-tris buffered solutions at ph 6.5 containing polyethylene glycol and calcium acetate. the crystals of the c-terminal domain were obtained using ammonium sulphate as a precipitant. the crystals of n-terminus domain diffract to at least 2.3 å and crystals of c-terminus domain -to 3.2 å using an in-house diffractometer with a mar research image-plate as a detector. progress towards the determination of cody structure will be presented. the gram-positive bacterium listeria monocytogenes is a facultative intracellular parasite. interactions of l. monocytogenes with the host cell are provided by a number of secreted and cell surface proteins. one of the most important virulence factors, actinpolymerizing protein acta, is surface attached via the hydrophobic c-tailed membrane anchor. despite, the membrane anchor acta was found in comparable amounts both on the cell surface and in the culture supernatant. the aim of the work was to investigate the mechanism of acta release and the role of this process in l. monocytogenes virulence. maldi-tof ms analysis of trypsin released acta suggested releasing due to proteolytic cleavage between histidine and threonine residues in the close vicinity of the membrane anchor predicted by the htmm analysis. the substitution of histidine with proline prevented acta release into the culture supernatant, although did not disturb its surface presentation. in silico analysis of eight other l. monocytogenes membrane-anchored surface proteins suggested the role for asparagine and threonine residues in specific proteolysis. the prediction was experimentally tested by substitution of the residues with alanine. the l. monocytogenes spontaneous mutant strain, unable to release membrane-anchored proteins into the culture supernatant, was isolated. the mutation was mapped outside the acta gene and presumably affected the corresponding peptidase. the mutation impaired the invasion of l. monocytogenes into the human epithelial-like hela cells that suggested the effect of the released proteins on signaling events that result in induced phagocytosis of the pathogen by normally non-phagocytic cells. angiotensin ii (ang ii) has been proposed to act as a regulatory peptide in the epidermal layer of human skin. while the expression of receptors and peptide precursors have been demonstrated in epidermis, the formation of ang ii and its inactivation have not been studied in detail. thus we have established a model system with cultured keratinocytes to examine the metabolism of ang i, ii and related peptides by intact epidermal cells. cultures were incubated with peptides in a minimal medium, which sustained cell viability for at least 24 h and the metabolism of peptides was monitored by chromatography (rp-hplc). with ang i as peptide substrate five major products were detected in keratinocyte culture media after 12 h incubation. a half-life of about 9 h was estimated for ang i and the slow degradation supports results of earlier studies revealing low activities of exopeptidases in a microsomal fraction from keratinocytes as compared to fibroblasts. the degradation of ang i was not affected by inhibitors of alanyl aminopeptidase, peptidyl dipeptidase a and neprilysin. since a peptide product formed from ang i in keratinocyte cultures resembled ang ii in hplc analysis, the activity of peptidyl dipeptidase a in these cells was assayed with hip-his-leu and the presence of the peptidase was confirmed by its sensitivity to captopril. further experiments showed that ang ii, iii and related peptides were degraded in keratinocyte cultures with rates similar to ang i and these reactions interfered severely with the formation of ang ii. immunohistochemical studies showed a strong positive staining for neprilysin and alanyl aminopeptidase in the dermal layer of human skin and at the epidermal-dermal junction confirming the results obtained with the cell cultures. soluble angiotensin converting enzyme-2 present in human plasma and urine p94/calpain 3 is the skeletal-muscle-specific calpain and is considered to be a modulator protease in various cellular processes. a defect in the p94 gene causes limb-girdle muscular dystrophy type 2a (lgmd2a), suggesting that p94 functions are indispensable for proper muscle functions. in sarcomeres, p94 localizes at z-, n2-and m line regions. although the binding partner for p94 at z-line has not been identified yet, n2-and m-line localization of p94 are considered dependent on its interaction with the n2a and m-line regions of connectin/titin, respectively. connectin is a gigantic sarcomeric protein playing an important role as a molecular template for sarcomeric organization, an elastic element generating passive tension, a platform for various protein ligands, etc. in this study, we focused on the molecular components associated with the n2a region of connectin/titin to extend our understanding on p94. intriguingly, a recessive mutation in the mouse connectin gene, mdm (muscular dystrophy with myositis), causes muscular dystrophy. there are two remarkable phenotypes consequential to mdm mutation. first, the mdm mutation abolishes p94 binding activity of connectin n2a fragment. second, in skeletal muscle from mice homozygous for mdm mutation, upregulation of cardiac ankyrin repeat protein (carp) is observed. carp also binds to n2a connectin at the n-terminal proximity of the region mutated by mdm. the effect of mdm mutation on p94 activity and the properties of n2a connectin as well as carp were analyzed using both animal model and cell culture systems. semliki forest virus (sfv) is well known model virus, which has been studied for decades. the main topic of this research was characterization and analysis of sfv replication machinery using approach based on use conditional-lethal mutants of viruses. the direct aim of the present study was to sequence and functionally characterize a panel of independent sfv temperature sensitive mutants. from all putative ts-mutations, identified in this study, two were mapped to nsp1 protein, four were mapped to nsp2 protein and one was founded in nsp4 region. number of assays were used to verify phenotypic effects of revealed mutations: titration of virus stocks at different temperatures, leak yield experiments, analysis of viral rna synthesis and viral polyprotein processing at different temperatures. nsp2 mutants had clear viral protease defect and accumulated non-cleaved polyproteins on different stages. besides all, biotechnological branch of our research is already developing. it includes improving of existing sfv based expression vector system by use of ts-mutations for the temperature regulation of foreign gene expression in mammalian cells. dipeptidyl peptidase iv activity and/or structure homologues (dash) in brain tumors pathogenesis of many diseases, including cancer, often involves improper proteolytic post-translational modification of biologically active peptides. association of dysregulated expression pattern of novel group of ''dipeptidyl peptidase (dpp)-iv activity and/or structure homologues'' (dash) with cancer development and progression has been suggested by several authors, including us [1] . dpp-iv enzymatic action as a common attribute of most of dash members modifies signaling potential of their substrates, biologically active peptides, not only quantitatively, but due to the changes in their receptor preferences also qualitatively. in this study, we have investigated expression (by real time rt-pcr and immunohistochemistry) and enzymatic activity (by biochemical assays and enzyme histochemistry) of plasma membrane localized dash members, in particular dpp-iv, fibroblast activation protein-alpha (fap) and attractin in human gliomas. it was revealed that varying quantities of dpp-iv, fap and attractin mrnas and proteins were coexpressed in the studied tumors. the majority of dpp-iv-like activity in the glioma tissue could be attributed to the canonical dpp-iv. this activity, assayed biochemically and expressed per mg of protein, was increased in high grade gliomas. inhibition studies suggested lack of enzymatically active attractin in the examined glioma tissues. the results of our pilot study demonstrate for the first time that both enzymatically active and inactive dash molecules are coexpressed in gliomas and suggest prevailing association of increased dpp-iv activity with high grade tumors. acknowledgment: this work was supported by iga nr/8105-3 and msmt 0021620808 vegf-c is involved in the neovascularization processes, steps essential for wound healing, cancer progression and many other physiological functions. zebrafish vegf-c processing and key: cord-021419-nypnib0h authors: olsufyeva, evgenia n.; yankovskaya, valentina s. title: main trends in the design of semi-synthetic antibiotics of a new generation date: 2020-03-17 journal: nan doi: 10.1070/rcr4892 sha: doc_id: 21419 cord_uid: nypnib0h this review summarizes main advances achieved by russian researchers in the synthesis and characterization of semi-synthetic antibiotics of a new generation in the period from 2004 to 2019. the following classes of compounds are considered as the basis for modification: polycyclic antibacterial glycopeptides of the vancomycin group, classical macrolides, antifungal polyene macrolides, the antitumour antibiotic olivomycin a, antitumour anthracyclines and broad-spectrum antibiotics, in particular, oligomycin a, heliomycin and some other. main trends in the design of modern anti-infective and antitumour agents over this period are considered in relation to original natural antibiotics, which have been independently discovered by russian researchers. it is shown that a new type of hybrid structures can, in principle, be synthesized based on glycopeptides, macrolides and other antibiotics, including heterodimers containing a new benzoxaborole pharmacophore. the review addresses the influence of the length of the spacer between two antibiotic molecules on the biological activity of hybrid structures. a combination of genetic engineering techniques and methods of organic synthesis is shown to be useful for the design of new potent antifungal antibiotics based on polyenes of the amphotericin b group. many new semi-synthetic analogues exhibit important biological properties, such as a broad spectrum of activity and low toxicity. emphasis is given to certain aspects related to investigation of a broad range of biological activity and mechanisms of action of new derivatives. the bibliography includes 101 references. the review addresses the influence of the length of the spacer between two antibiotic molecules on the biological activity of hybrid structures. a combination of genetic engineering techniques and methods of organic synthesis is shown to be useful for the design of new potent antifungal antibiotics based on polyenes of the amphotericin b group. many new semi-synthetic analogues exhibit important biological properties, such as a broad spectrum of activity and low toxicity. emphasis is given to certain aspects related to investigation of a broad range of biological activity and mechanisms of action of new derivatives. the bibliography includes 101 references. antibiotics are commonly used in the treatment and prevention of various infectious diseases. one of the major problems of modern chemotherapy is the disappointing efficacy when using available drugs against resistant bacterial strains. natural antibiotics, i.e., antibiotics produced by various microorganisms, have been and continue to be an important source of new highly active antimicrobial and antitumour agents. one of the most relevant approaches to the design of new drugs relies on targeted chemical transformations of natural antibiotics. 1 in the world science, considerable efforts are currently underway to combat the problem of resistance of microorganisms to available drugs. however, in comparison with other drugs, the development of new antibiotics is not carried out sufficiently. the design of anti-infective drugs and the creation of marketable products are still a challenge. 2 since the development of medicines for the treatment of chronic diseases is much more profitable and because of high requirements for safety, large cap pharmaceutical companies (big pharma) shut down their antibiotic research projects. currently, small-and medium-sized enterprises are developing a majority of new drugs through investments, venture capital, etc. because of high demands for new anti-infective drugs and extremely high cost of these works, cross-country collaborations are needed for research in this field. only a few new compounds were approved for therapeutic use in human medicine or have completed phase-iii clinical trials. 3 the problems are compounded by the fact that the increasing percentage of the population, particularly in developed countries and russia, suffer from infections that were not earlier dangerous, i.e., from opportunistic infections. this is due to a significant decrease in the immune status of the population caused by natural or man-made factors. the translation of semi-synthetic antitumour antibiotics (e.g., doxorubicin) into clinics resulted in the development of gold standard chemotherapeutic agents. many antibiotics have made a great contribution to understanding of mechanisms of development of resistance in bacterial and tumour cells. due to high innate or acquired drug resistance of cancer cells, chemotherapy of malignant tumours is often ineffective. the international research community has focused its attention on the search for new, more effective and less toxic antitumour agents. one of the most rational approaches to the targeted therapy is based on the search for inhibitors of important tumour cell targets among natural products, primarily antibiotics. 4 even the repurposing of known antitumour antibiotics is considered in order to address the problem of antibiotic resistance of antiinfective agents. 5 researchers of the gause institute of new antibiotics (gina) headed by academician of the ussr academy of medical sciences g.f.gause in the 1960 ± 1990s made considerable contribution to the discovery of a series of original antibacterial and antitumour agents (a total of 15 compounds), their characterization and introduction to medical practice. major achievements of the institute during this period are considered in the review. 6 antibiotics comprise an important class of natural products with unique structural diversity. chemical transformations of natural antibiotics imply a change of particular functional groups of the starting molecules with preservation of structural elements responsible for biological activity. the structure determines the possibility of chemical transformation of the antibiotic and reaction conditions. for example, many antibiotics contain nitrogenous and(or) nitrogen-free sugars, which are easily eliminated in acidic or alkaline media. many antibiotics are sensitive to oxidants, are poorly soluble in organic media or, on the contrary, in aqueous solutions, etc. on the other hand, in the case of similar structures of certain moieties [e.g., the presence of nh 2 , co 2 h, oh, c(o), etc. groups)], methods developed for one class of antibiotics can be applied to antibiotics of another class. the goal of synthetic chemists is to transform natural products with preservation of the sites responsible for biological activity. besides, targeted modification can be performed to gain better understanding of the mechanisms of action, in particular in order to investigate the interaction between the antibiotic and the target. in this review, the following classes of compounds are considered as scaffolds for the synthesis of new antibiotics: polycyclic glycopeptides of the vancomycin ± teicoplanin group, classical macrolides, macrolides of the amphotericin b ± oligomycin group, anthracyclines, aureolic acid derivatives, heliomycin, synthetic benzoxaboroles and some other antibiotics. such representatives as eremomycin, carminomycin, olivomycin a, oligomycin a and heliomycin 6 . olivomycin a 364 6.1. modification of olivomycin a at the aromatic ring of the aglycone 364 6.2. modification of olivomycin a at the side-chain 2 h -keto group of the aglycone 366 6.3. modification of the side chain at the c(2 h )7c (3 h the discovery of vancomycin (1) and teicoplanin (2) (fig. 1 ) has given impetus to research on polycyclic glycopeptide antibiotics. 7 natural antibiotics 1 and 2 are still used in medical practice and are considered as reserve antibiotics. they are commonly applied for the treatment of infections caused by gram-positive cocci, particularly, methicillinresistant staphylococcus aureus (mrsa) strains. glycopeptide antibiotics bind with high affinity to the terminal d-ala-d-ala group of the growing peptidoglycan chain on the outer bacterial cell wall, thereby inhibiting the enzymes transpeptidase and transglycosylase. the vancomycin resistance in enterococcus strains (vre) (for vana and vanb phenotypes) arises due to replacement of the d-ala-d-ala group by d-ala-d-lactate, which weakly interacts with the antibiotic. semi-synthetic glycopeptide analogues, such as oritavancin, telavancin and dalbavancin, have recently been used worldwide in medicine. these drugs only partially solve the problem of the treatment of infectious diseases caused by vancomycinresistant enterococci. 7, 8 the search for more effective glycopeptide analogues is an ongoing process. 7 ± 9 eremomycin 3 (see fig. 1 ), the natural antibiotic of this group, was discovered in the gause institute of new antibiotics. 17 this compound differs from vancomycin (1) by the absence of a chlorine atom and the presence of the additional amino sugar eremosamine in the side group of amino acid 6 (aa6), as well as by the structure of the amino sugar (4 h -epivancosamine or eremosamine) at the d-glucopyranose moiety attached to aa4. eremomycin (3) is 3 ± 5 times more active against gram-positive bacteria than antibiotic 1; however, drug 3 is also ineffective against vre and vancomycin-intermediate resistant staphylococcus aureus (visa). in recent years, series of new semi-synthetic derivatives of eremomycin, vancomycin and teicoplanin active against resistant vre and visa strains were prepared. 8 ± 10 figure 1 presents main possible directions of modification of the cand n-terminal groups of the peptide core (a and f ), 3 h -amino sugar (b), the amide group of asparagine (asn) (c), sugar elimination (d ) and edman degradation (e) for antibiotics 1 ± 3. the presence of (benzotriazol-1-yl)oxytripyrrolidinophosphonium hexafluorophosphate (pybop) as the peptide coupling reagent afforded a series of new carboxamide derivatives of eremomycin 4 ± 6 (scheme 1, fig. 1 a3) . 11 ± 14 after the purification, these compounds were isolated in *50% ± 80% yields. eremomycin pyrrolidide (4) has high in vitro antibacterial activity against sensitive and resistant gram-positive bacterial strains, including mrsa, visa and vre isolates. 13, 14 besides, compound 4 is much more effective in the treatment of induced sepsis in mice compared to vancomycin (1) and does not cause a pseudoallergic reaction typical of many antibiotics of this group. compound 4 was successful in preclinical evaluation (in collaboration with the limited liability company`medicine technology') and was recommended for further clinical trials. 13 eremomycin n-adamantan-2-ylamide (5) was synthesized in a similar way as amide 4 (see scheme 1). 15 in in vitro assays, compound 5 exhibits activity against mrsa, visa, vre and bacillus anthracis strains. this compound is also effective against ciprofloxacin-resistant strains of bacillus anthracis. model in vivo assays in mice infected with s. aureus or bacillus anthracis showed that compound 5 provides a higher survival rate of animals compared to ciprofloxacin and has pharmacologically relevant properties, exhibiting an excellent distribution in tissues. the synthesis of eremomycin carboxamides containing bulky substituents, such as 2-aminoadamantane (2-ad) (compound 5), in the presence of pybop at ph * 8.5 afforded the previously characterized unsubstituted eremomycin amide (6) as a by-product. 16 compound 6 is produced by the competitive amidation reaction of the antibiotic with ammonia, which is eliminated through transpeptidation of asparagine-containing peptides in an alkaline medium. an original method was developed for the selective introduction of different amino acids containing a hydrophobic substituent into glycopeptide antibiotics 1 or 2 via selective aminoacylation of the 3 h -amino group of the amino sugar moiety of the disaccharide branch. 17 for instance, the reaction of vancomycin 1 with n-fmoc-(n-n-octyl-o-4benzyl)-l-alanine n-hydroxysuccinimide (osu) ester gave figure 1 . structures of vancomycin (1), teicoplanin a2-2 (2) and eremomycin (3) and directions of their chemical modifications: amidation (a), acylation (b), alkaline hydrolysis of the c(o)nh2 group to co2h followed by amidation (c), sugar elimination (d ), edman degradation (e) and modification of the n-terminal amino group of the peptide core ( f ). fig. 1 b1) . in this reaction, the n-terminal group of the peptide core of the antibiotic remains intact. the n-fmoc protecting group can easily be removed by the treatment with a 5% secondary amine solution. compound 8 exhibits high activity against sensitive and resistant clinical strains of gram-positive bacteria, including vre. 18 in order to study in detail the interaction between the antibiotic and the target in the intact bacterial cell by solid-state nmr spectroscopy using the rotational-echo double resonance (redor) technique, 15 nh 2 -or f-labelled substituents were introduced into amino acid residues 3 (aa3) and(or) 7 (aa7) of the peptide chain of the antibiotic eremomycin (3). 19 the 15 n label was introduced in the vicinity of the binding pocket of the antibiotic. this was accomplished using carboxyeremomycin (9) , which was synthesized previously by the selective alkaline hydrolysis of compound 3 in a saturated aqueous solution of ba(oh) 2 . under these conditions, vancomycin (1) decomposes. carboxyeremomycin [ 15 n]-bisamide 10 was synthesized by the reaction of compound 9 with appropriate amines in the presence of pybop (scheme 3, fig. 1 a3,c3) . 19 eremomycin 4-fluorophenyl-n-piperazide (11) was synthesized by the conventional amidation method in the presence of pybop. the redor experiments were performed using intact staphylococcus aureus cells, which were grown in a culture medium containing bioprecursors with isotope-labelled atoms (e.g., 13 c-amino acid). the 15 n-or f-containing antibiotic that was added to the medium inhibits bacterial growth by forming a stable complex with 13 c-labelled peptidoglycan moieties (see fig. 2 , hydrogen bonds are indicated by dashed lines). 19, 20 the study of the complex with compound 10 provides an estimate of the distance from the distance between the c-terminal [ 15 n]-amide of eremomycin (10) and l-[ 13 c(3)]ala 1 of the peptidoglycan stem is 3.5 # a (see fig. 2 , a solid arrow). 20 consequently, higher activity of eremomycin amide 10 (compared to antibiotics 1 or 3) against resistant visa staphylococci can be attributed to the fact that this compound interacts with the peptidoglycan not only via a classical model (i.e., with the d-ala-d-ala target) but also with the l-[ 13 c(3)]ala group of its stem. besides, there is an additional binding site of derivative 11 to the target, which can also account for its high antibacterial activity against vre and visa. 21 previously, it was shown that the elimination of sugars (see fig. 1 d ) and the introduction of a hydrophobic residue into the aglycone can give rise to aglycone derivatives of antibiotics exhibiting activity against different types of enveloped viruses. 22 the modification of the eremomycin aglycone (12a), its de-d-meleu analogues (hexapeptide, 13a), which was produced by the cleavage of amino acid 1 (aa1) using the edman method (see fig. 1 e), and the teicoplanin aglycone (14) gave a series of new hydrophobic derivatives. (1-adamantylmethyl)amide of the eremomycin aglycone (12b) and its hexapeptide analogue (13b) are derived by the reaction of 1-adamantylmethylamine with 12a or 13a in the presence of diphenylphosphoryl azide (dppa) (scheme 4). diphenylphosphoryl azide rather than pybop is the reagent of choice for the amidation of aglycones, because the reactions in the presence of pybop often afford by-products containing the pybop moiety in the phenol group of the aglycone at aa4. 23 the acylation of compound 14 with di-tert-butyl dicarbonate (boc 2 o) followed by amidation under standard conditions in the presence of pybop gives the disubstituted derivative ð (2-adamantyl)amide of the n-boc-teicoplanin aglycone (15) . the acylation of 14 with 1-adamantylmethyloxy carbonate (adoc 2 o) affords the n-adoc-teicoplanin aglycone (16) (see fig. 1 f, scheme 4). compounds 12b, 13b and 14 ± 16 exhibit high in vitro activity against different corona-and flaviviruses, in partic-ular feline infectious peritonitis virus (fipv) and the coronavirus (sars-cov). 24 the most interesting data were obtained when studying antiviral activity of (1-adamantylmethyl)amide of the eremomycin aglycone (12b) and its de-(d-meleu) analogue (13b) against human immunodeficiency viruses (hiv): ic 50 = 1.6 and 5.5 mmol l 71 for hiv-1, 7.0 and 3.5 mmol l 71 for hiv-2, respectively. compounds of type 13b are promising selective anti-hiv agents because they cannot bind to bacterial targets. 23 apparently, they cannot induce resistance of bacteria during long-term application and can be used in the future for the prevention of hiv infections. the doubly modified teicoplanin derivative ð n-bocprotected 2-adamantylamide of the teicoplanin aglycone 15 ð exhibits high in vitro activity against a series of flaviviruses: hepatitis c virus (hcv), 25 yellow fever virus (yfv), japanese encephalitis virus (jev), tick-borne encephalitis virus tbev) and dengue virus (denv). 25, 26 compound 15 is unique in that it can inhibit replication of the closely related denv and hcv viruses by different mechanisms: in the former case, the inhibition occurs in the stage of virus entry in the host cell; in the latter case, after virus entry. protein kinases play an essential role in the virus entry in the cell and virus replication. hence, 15 analogues of the eremomycin and teicoplanin aglycones (including compounds 12a,b, 13a,b and 14 ± 16) were tested on a panel of 12 recombinant human protein kinases (pks) and two rat liver pks (ck1 and ck2). 27 these compounds were shown to inhibit pk activity by 50% at a concentration of <10 mmol l 71 and by 90% at a concentration of 10 mmol l 71 . teicoplanin aglycone derivatives 15 and 16 exhibit higher activity against many pks compared to eremomycin derivatives 12b and 13b, which also correlates with their higher activity against many types of enveloped viruses. the kinetic analysis of the inhibition of protein kinase ck2a demonstrated that teicoplanin n-adoc-aglycone 16 does not compete with atp and peptide substrates. 27 on the available data, it was suggested that one of the mechanisms of antiviral activity of glycopeptide derivatives can be based on the inhibition of serine/threonine protein kinases. the synthesis of hybrid analogues containing covalently bonded compounds of different classes (dual-acting antibiotics) with different spectra of antibacterial activity is a promising approach to the search for new antibacterial agents to combat antibiotic resistance of bacteria. 28, 29 boronic acids and benzoxaboroles are compounds capable of interacting with various biologically important components of the living cell, such as alcohols, amino alcohols, carbohydrates, rna and some peptides. a new class of synthetic antibiotics possessing antifungal, antimicrobial and antiparasitic activity was designed and synthesized based on benzoxaboroles and is currently developed by anacor pharmaceuticals (usa). 30 certain starting benzoxaboroles used in the synthesis also exhibit biological activity (see below). series of hybrid analogues 17 ± 20 linked to the borole or benzoxaborole moiety either directly or through a spacer were synthesized for the first time from glycopeptides 1 and 3. to introduce a substituent containing a boronic acid moiety into molecule 1 or 3, it is necessary to employ picolinic acid as a protecting group, which is easily removed in a weakly acidic medium (scheme 5). 31 the amidation of the carboxyl group of antibiotics 1 and 3 with 4-or 3-aminomethylphenylboronic acid picolinate esters in the presence of pybop gave new carboxamides of these antibiotics (17a ± 20a). the hydrolysis of the picolinic group under mild conditions in a weakly acidic aqueous medium affords derivatives 17b ± 20b containing the unprotected boronic acid moiety. borole-containing derivatives 17 ± 20 were found to be as effective as the starting antibiotics 1 and 3. eremomycin derivative 19b exhibits the highest activity against gram-positive bacteria and is more effective against resistant staphylococcus strains (visa) compared to compounds 1 and 3. a series of vancomycin conjugates containing different types of benzoxaborole substituents were synthesized: amido derivatives 21a,b, n-acyl derivatives (22) n-alkyl derivatives (23) (scheme 6). similar schemes were applied to synthesize benzoxaborole derivatives of eremomycin (7) (see scheme 1) and the teicoplanin aglycone (scheme 7). 32 carboxamides of eremomycin (7) (see scheme 1), vancomycin (21a) (see scheme 6) and the teicoplanin aglycone (24a) (see scheme 7) were synthesized by a standard procedure based on the treatment of compounds 1, 3 and 14, respectively, with 3-(aminomethyl)benzo[c] [1, 2] oxaborol-1(3h)-ol in the presence of pybop. the reaction of compound 1 or 14 with o-amino-n-alkylamines affords the corresponding amides 21b and 24b,c (n = 2, 3 and 5) containing a longer spacer. the reactions with osu-activated esters of the same in situ generated compounds were used to synthesize n-[3-(1-hydroxy-1,3-dihydrobenzo[c] [1, 2] oxaborol-7-yl)propanoyl] derivatives of vancomycin (22) and the teicoplanin aglycone (25a). the alkylation of vancomycin (1) with appropriate aldehyde in the presence of nabh 3 cn affords n,n hdi(1-hydroxy-1,3-dihydrobenzo[c] [1, 2] oxaborole-6-methyl)vancomycin (23) in quantitative yield (see scheme 6) . 32 the amidation of n-acyl-substituted teicoplanin aglycone 25a with appropriate amine (in a similar way as the synthesis of amides 21 and 24a) gave disubstituted teicoplanin aglycone derivative 25b. the five-membered oxaborole ring cleavage is not observed in various reactions of benzoxaboroles (see scheme 7) . the presence of peaks at m/z 1619. 49 [m7oh], 1474.39 and lower (1312. 34 and 1284.34) in the tandem mass spectrometry (esi-ms/ms-mrm) spectrum of compound 22 indicates that the antibiotic molecule contains a substituent in the n-terminal amino group of the peptide core rather than in the amino sugar n(3 h ) group of vancosamine (fig. 3) . 32 vancomycin derivatives 21a, 22 and 23 proved to be less effective against gram-positive bacteria than the starting compound 1, except for amide 21a, which exhibits activity comparable with that of vancomycin 1. 32 hybrid derivatives, in which benzoxaborole and the teicoplanin aglycone are linked by a spacer with a particular length, exhibited the highest antibacterial activity against clinical isolates of gram-positive bacteria. 3-amino-n-(1hydroxy-1,3-dihydro[c] [1, 2] oxaborol-6-yl)propylamide of the teicoplanin aglycone (24c, n = 2) possesses particularly high activity, in particular against vancomycin-resistant strains. 32 besides, this compound exhibits moderate activity against vancomycin-resistant enterococci (vre); the minimum inhibitory concentration (mic) is 4 ± 8 mg ml 71 . an increase or a decrease in the spacer length and the introduction of two benzoxaborole substituents into the n-and c-terminal groups of the peptide were found to decrease antibacterial activity. the broad-spectrum antibacterial drug kanamycin a (26a) is an important antibiotic of the aminoglycoside (aminocyclitol) class, which is still used in medicine for the treatment of many infectious diseases and also in agriculture. 7 aminoglycosides are active against gram-positive and gram-negative bacteria. the mechanism of their action is related to the interaction with the decoding site (a site) of the 16s subunit of ribosomal ribonucleic acid (rrna), which leads to disturbance of translation, i.e., protein biosynthesis. according to the literature data, a number of semi-synthetic derivatives of a new generation were synthesized based on aminoglycosides. 33 various heterodimeric aminoglycoside conjugates with other antibiotics were reported, and some of them are used in medicine. 28, 29 the synthesis of hybrid kanamycin a conjugates with glycopeptides 1 and 3 was described for the first time in our publication. 34 kanamycin a (26a) was conjugated with compounds 1 or 3 via an amino group of the antibiotic at the 1 position of 2-deoxy-d-streptamine. the acylation of this amino group is known to reduce the risk of the development of resistance, because it prevents deactivation of the antibiotic by enzymes. the amino group at the 3 position of 2-deoxy-dstreptamine and the 6 h -amino group of 6 h -deoxy-6 h -amino-d-glucopyranose of aminoglycoside 26a were protected by the benzyloxycarbonyl group (cbz). 3,6 h -bis-(cbz)-kanamycin a (26b) was synthesized by the reaction of the zinc complex of compound 26a with cbzcl in the presence of a base (et 3 n) using a modified method 35 (scheme 8). (mic *2 ± 4 mg ml 71 for compounds 27, 28a,b) and vre stains (mic = 8 mg ml 71 for compound 28a). 34 based on the results of these studies, methods were developed for the selective introduction of functional groups at the amino sugar amino group of vancomycin (1) or eremomycin (3), with the terminal methylamino group of the peptide core of the antibiotic remaining intact. 17 the amidation of the terminal carboxyl group of these antibiotics with various amines, including amines with bulky substituents, was studied in detail. 12, 13, 15 an unusual byproduct of amidation (previously unknown for these classes of antibiotics) was isolated, and the optimal conditions were found for the amidation providing the target products in high yields. 15, 16 the introduction of various groups into glycopeptides at certain positions of the molecule can give new derivatives active against bacteria that are resistant to the initial antibiotics ð glycopeptide-resistant enterococci. 5, 10 this resulted in the discovery of compounds exhibiting high activity against glycopeptide-resistant enterococci (mic = 2 ± 8 mg ml 71 ) and staphylococcus aureus with intermediate resistance to glycopeptide antibiotics (mic = 1 ± 2 mg ml 71 ). generally, eremomycin derivatives possess higher in vitro antibacterial activity than analogous vancomycin derivatives and show significant advantages over vancomycin in the treatment of animals in a mouse model of staphylococcal sepsis. 10, 13 conditions were found for the selective introduction of isotopic labels at both the terminal carboxyl group and the asparagine residue (aa3) of the peptide core of eremomycin, with carbohydrate moieties and other labile functional groups remaining intact. 19 the investigation of interactions of these compounds with native cells of gram-positive bacteria by the redor technique confirmed the mechanisms of action of this group of antibiotics proposed in our previous studies. 20, 21 modifications of glycopeptide aglycones at the carboxyl and(or) amino group were performed in a series of studies. 22 ± 25 this resulted in the discovery and characterization of a new class of polycyclic peptides exhibiting antiviral activity at micromolar concentrations against hiv-1 and hiv-2, as well as against the enveloped viruses hcv, denv and many other. 22 ± 26 the correlation between antiviral and pk inhibitory activities was established for a class of hydrophobic derivatives of glycopeptide aglycones. 27 the first heterodimeric conjugates of glycopeptide antibiotics with boroles, 31, 32 and with kanamycin a 34 were synthesized. the conjugates exhibit activity against resistant vre and(or) visa strains. the synthesis of chimeric (heterodimeric) macrolide-based antibiotics is a promising area of research to search for new antimicrobial agents. 28 these antibiotics are among the most effective broad-spectrum antibacterial agents. the semi-synthetic antibiotics clarithromycin (29) and azithromycin (30) are commonly used in medicine for the treatment of various infectious diseases caused by many gram-positive and gram-negative bacteria (fig. 4) . azithromycin (30) has the best pharmacological profile among macrolide antibiotics. the mechanism of action of macrolides is based on the inhibition of protein synthesis. the target of macrolides is the peptidyl transferase centre on the large 50s subunit of bacterial ribosome. however, clarithromycinand azithromycin-resistant clinical isolates of bacteria were isolated. 36 researchers at the gause institute of new antibiotics have developed methods for the conjugation of macrolide antibiotics with benzoxaboroles or polycyclic glycopeptide antibiotics and synthesized series of new chimeric antibiotics. conjugates based on clarithromycin (29), azithromycin (30) and various substituted benzoxaboroles were synthesized by the targeted modification of macrolides at the c(9), c(2 h ) and c(4 hh ) atoms and the c(11) ± c(12) bond (see fig. 4 a ± d ). according to the literature data, the introduction of arylalkyl groups at the 4 hh position of the cladinose moiety may help antibiotics overcome resistance caused by methylation of the macrolide-binding site of 23s rrna of the large ribosomal subunit. 37 a method was developed for the introduction of aminobenzoxaboroles at the c(4 hh ) atom of the cladinose moiety of the antibiotic through the carbamoyl group. 38 hybrid structures containing hydroxamic acid-derived benzoxaborole at the c(9) keto group of the aglycone were prepared, because modification of this group does not lead to the loss of antibiotic activity. scheme 10 shows the synthesis of conjugates based on clarithromycin 29 via the introduction of benzoxaborole groups (a and b) into the antibiotic molecule at the c(9) atom of the aglycone or at c(4 hh )7o-cladinose with acetyl protection of the c(2 h )7oh group of desosamine. 38 the former approach is based on the treatment of clarithromycin (29) with aminoacetic acid giving intermediate clarithromycin 9-syn(anti)-(o-carboxymethyl)oxime (31a). the reaction of 31a with aminobenzoxaboroles ha figure 4 . structures of the macrolide antibiotics clarithromycin (29) and azithromycin (30) . arrows indicate the directions of modification: at the 9 position of the aglycone (a), at the c(2 h )7oh group of desosamine (b), at the c(4 hh ) atom of cladinose (c), the formation of c(11),c(12)-cyclic carbonate and modification of the c(11) atom (d ). or hb gives the corresponding amides of clarithromycin (e/z)-9-carboxymethoxime 31b,c (see scheme 10). another approach was accomplished by a modified procedure 39 involving the following four steps: the protection of the c(2 h )7oh group of desosamine by the acetyl group giving 2 h -oac-clarithromycin (32), the transformation of the latter into activated 2 h -oac-clarithromycin 4 hh -o-1h-imidazole-1-carboxylate (33) by the treatment with carbonyldiimidazole (cdi), the amidation of 33 with amines ha or hb in the presence of the peptide coupling reagent 1,8-diazobicyclo [5.4 .0]undec-7-ene (dbu) giving 2 h -oac-substituted carbamoyl derivatives of clarithromycin 34a,b, and the deacetylation of 34a,b by heating in methanol to form target unprotected carbamoyl derivatives of clarithromycin 35a,b. compounds 31b,c and 35a,b exhibit the inhibitory effect against staphylococci and streptococci comparable with the activity of starting compound 29. in these assays, derivatives at the c(4 hh )-cladinose position were found to be more effective than the derivatives at the c(9) position of the aglycone of antibiotics 31b and 31c. compound 35b is the most effective against the strains staphylococcus epidermidis atcc 12228 and streptococcus pneumoniae atcc 49619. clarithromycin analogues 31c and 35b possess an opposite activity against gram-negative bacteria, such as sensitive strains of e. coli and resistant strains of e. coli (tolc and tolc puc erm42). thus, compound 31c is more active than 35b. in the former case, e. coli tolc and tolc puc erm42 are bacterial strains containing the outer membrane protein tolc, which is responsible for antibiotic efflux from the cell. in the latter cases, the strain contains, apart from tolc, the puc plasmid cloning vector and methylase erm42. 38 attempts were made to extend the method developed for the synthesis of c(4 hh )-substituted clarithromycin ± benzoxaborole conjugates to the synthesis of related azithromycin conjugates (scheme 11). 39 it appeared that the success of introducing the aminobenzoxaborole moiety into a macrolide antibiotic depends on the structure of antibiotics 29 and 30, as well as on the structure of aminobenzoxaborole. the acetylation of azithromycin (30) giving the 2 h -oac derivative (36) followed by the treatment of the latter with n,n h -carbonyldiimidazole in the presence of et 3 n produces the desired activated imidazole derivative ð azithromycin 2 h -oac-4 hh -o-1h-imidazole-1-carboxylate (37) (see scheme 11) . however, unlike the synthesis of clarithromycin analogue 34a, the amidation of compound 37 with 7-(hydroxy-1,3-dihydrobenzo[c] [1, 2] oxaborole)methylamine in the presence of dbu does not give the desired outcome. the introduction of the latter amine was accomplished using the trisubstituted derivative, the 11,12-cyclic carbonate azithromycin 2 h -oac-4 hh -o-1h-imidazole-1-carboxylate 38 as the substrate. compound the same conditions as those used for 37 was not successful (see scheme 11) . 40 meanwhile, this reaction with another amine containing an aminoethyl spacer gives the corresponding azithromycin carbamoyl derivative 39 (see scheme 11) . 40 however, the elimination of the 2 h -oac group finally results in the decomposition of the deacetyl derivative during its purification on silica gel. an alternative procedure for the introduction of benzoxaboroles into molecule 30 using carboxy derivatives and diaminoalkane spacers (scheme 12) proved to be more successful. 40 the treatment of imidazole derivative 38 with stronger bases, such as diaminoethane or 1,3-diaminopropane, in the presence of dbu resulted in the formation of aminoalkylcarbamoyl derivatives 40 (n = 2) and 41 (n = 3). the subsequent acylation of the latter with various benzoxaborole acids under standard conditions (dcc, hobt) gives a series of acylaminoalkylbenzoxaborole-containing carbamoyl derivatives of 11,12-cyclic carbonate, 2 h -oacazithromycin 42a ± 44a (see scheme 12) . the deacetylation of these compounds affords the corresponding cyclic carbo-nates 42b ± 44b containing the free c(2 h )7oh group of the desosamine moiety (r 1 = h) in quantitative yields. compound 46b and its 2 h -oac analogue 46a were synthesized from azithromycin 2 h -oac-4 hh -o-1h-imidazole-1-carboxylate 37 through intermediate 2 h -oac analogues 45 (n = 2, 3) (scheme 13). 40 therefore, the synthesis of compound 46a and its 2 h -oac analogue 46b showed that the introduction of the acylaminoalkylbenzoxaborole moiety can be accomplished using a scheme described above without protection of the c(11)7oh and c(12)7oh groups by cyclic carbonate. the evaluation of antibacterial activity of 4 hh -o-substituted derivatives 39, 42a ± 44a (n = 2), 42b ± 44b (n = 2, 3) and 46b (n = 2, 3) compared with that of compound 30 showed that the activity of compounds 39, 42 ± 44 and 46 against gram-negative bacteria (5 isolates) is lower than that against gram-positive bacteria (8 isolates). for example, the activity of compounds 39, 42a (n = 2), 43a (n = 3) and 42b (n = 3) against the gram-positive strains streptococcus pyogenes atcc 19615 and propionibacterium acnes atcc 6919 is comparable with that of the starting compound 30, while conjugates 42b (n = 3), 43a (n = 2), 43b (n = 2) and 44b (n = 2) are more effective than compound 30 against the strains streptococcus pneumoniae atcc 49619 or enterococcus faecium. the presence of the 2 h -oac group or 11,12-cyclic carbonate in analogous hybrid antibiotics was found to have almost no effect on antibacterial activity. for compounds 42a (n = 2, 3), 43a (n = 2, 3), 44a (n = 3), 42b ± 44b (n = 3) and 46b (n = 2, 3), the mechanism of antibacterial activity was studied using the prfpcer-trpl2a reporter construct, which responds to inhibitors of translocation of the ribosome along the matrix nucleic acid (mrna). 40 all compounds were found to inhibit the peptide chain growth at the exit from the ribosome tunnel like typical macrolide antibiotics. it is worth noting that one of the starting benzoxaborole acids, 3-(1-hydroxy-1,3-dihydrobenzo[c] [1, 2] oxaborol-7-yl)propanoic acid (see schemes 12 and 13, marked with an asterisk), also exhibited activity in this assay. 3.3. azithromycin ± benzoxaborole conjugates at the 11-oh group of the aglycone 11,12-cyclic carbonate can be used not only as the protecting group for two hydroxyl groups but also as the activated group to introduce benzoxaborole substituents at the 11 position of antibiotics. 41 the reaction of 11,12-cyclic carbonate azithromycin 2 h -oac derivative 47, which was generated from azithromycin (30) in two steps (treatment with ethylene carbonate followed by acylation of the 2 h -o group of the desosamine moiety), with diaminoalkane gave 2 h -oacetylazithromycin 11-aminoalkylcarbamates 48 (n = 3, 5) (scheme 14). the acylation of compound 48 with benzoxaborole acids under standard conditions (dcc, hobt) produced a series of azithromycin 2 h -oac derivatives 49a ± 51a. the deacetylation of these compounds afforded target benzoxaborole derivatives 49b ± 51b. new hybrid antibiotics 49b ± 51b exhibit broader-spectrum antibacterial activity against gram-positive and gram-negative bacteria compared to azithromycin (30) and tobramycin. compound 50b proved to be the most effective compound in this series, but its activity is lower than that of compound 30. the modified antibiotics do not overcome the antibiotic resistance in mrsa strains (strain atcc 33591). higher activity of these three compounds against the sensitive strain s. pneumonia atcc 6301 compared to tobramycin (mic is 40.06 ± 0.25 versus 4 mg ml 71 ) is a particularly valuable property. 41 , or , or , dcc, hobt; dcc is n,n h -dicyclohexyl carbodiimide, hobt is 1-hydroxybenzotriazole; in the former case, the reaction of azithromycin 11-aminoalkylcarbamates 48 (n = 3, 5) with antibiotics 1, 3 or 13 in the presence of pybop affords the corresponding derivatives of vancomycin (52, 53) , eremomycin (54) or the teicoplanin aglycone (55, 56) (scheme 15). 42 in the latter case, 11,12-cyclic carbonate azithromycin 4 hh -o-alkylaminocarbamoyl derivatives 40 and 41 are amidated with antibiotics 1, 3 or 13 in the presence of pybop (scheme 16). after the removal of the 2 h -o-acetyl protecting group from compounds 57a ± 61a and the column chromatographic separation on silanized silica gel followed by sephadex lh-20 chromatography, five new conjugates 57b ± 61b were isolated in 35% ± 45% yields based on the corresponding starting antibiotic. 42 antibacterial activity of derivatives 52 ± 55 modified at the c(11)7oh group of the aglycone was evaluated compared to the starting antibiotics vancomycin (1) and azithromycin (30) on a panel of gram-positive and gramnegative bacterial strains (8 and 3 strains, respectively). 42 none of the conjugates exhibited activity against gramnegative bacteria, which attests to the absence of the effect of the azithromycin moiety active against gram-negative bacteria. generally, compounds 52 ± 55 display similar or somewhat lower activity against gram-positive bacterial strains compared to compounds 1 and(or) 30, the activity against staphylococci being higher than that against the streptococci s. pneumoniae 49619 atcc and s. agalactis 52-2. azithromycin ± teicoplanin aglycone conjugate 56 containing a long spacer (n = 5) exhibits higher activity against all tested gram-positive bacterial strains (staphylococci and 42 derivatives at the 4 hh -cladinose position show a similar tendency. thus, they are inactive against gram-negative bacteria. the fact that the hybrid structures are ineffective against e. coli 25922 atcc and other gram-negative bacterial strains indicates that they cannot penetrate the outer phospholipid layer of the bacterial cell. in all the tested gram-positive bacterial strains, compounds 52 ± 55 exhibited activity comparable to or higher than that of azithromycin (30) and vancomycin (1) . their activity is provided by the presence of the glycopeptide moiety. unlike hybrid vancomycin analogue 58b, hybrid eremomycin analogue 59b displays significant activity against the vancomycin-resistant enterococci (vre) strains enterococcus faecium 569 and enterococcus faecalis 560 (mic = 3.2 and 6.5 mmol l 71 ), which can be attributed to the effect of the azithromycin moiety attached to the c-terminal group of the peptide core of antibiotic 3. 42, 43 the mechanism of action against gram-positive bacteria was confirmed by quantum chemical calculations of the energy of interaction dg 298 in relation to hybrid antibiotics 58b and 59b with the model d-ala-d-ala ligand typical of glycopeptides. 43 these studies resulted in the development of methods for the synthesis of macrolide-based hybrid antibiotics containing benzoxaborole as a new pharmacophore. 38, 40, 41 the behaviour of the macrolide antibiotic aglycone in chemical reactions was found to be affected by its structure, in particular it depends on the presence of an additional methylamino group in azithromycin (30) . 38, 40 the position of the benzoxaborole substituent was shown to influence the antibacterial activity of antibiotics 29 and 30. it was established that the c(11)-substituted analogues are less effective inhibitors of gram-positive and gram-negative bacteria compared to 4 hh -substituted analogues. 40, 41 the presence of 11,12-cyclic carbonate or the 2 h -o-acetyl group in the azithromycin molecule was shown to have no significant effect on the antibacterial activity of the conjugates, while an increase in the spacer length generally leads to an increase in activity of the final compounds. a method was developed for the synthesis of a series of chimeric antibiotics based on glycopeptides and azithromycin (30) . 42 the activity of almost all the synthesized compounds against the tested gram-positive bacterial strains, including vancomycin-resistant strains, is similar to or higher than that of the starting antibiotic. the range of antibacterial activity of the resulting hybrid derivatives and quantum chemical calculations suggest that the antibacterial activity is determined by the presence of the glycopep carbohydrate-containing polyene macrolides are commonly used in medicine for the treatment of both superficial and systemic mycoses due to their high activity and a broad spectrum of action. 44, 45 the mechanism of action of polyene macrolides is related to their ability to interact with sterol-containing cytoplasmic membranes and form pores (channels) in these membaranes, by which ions leave the cell causing its death. the efficacy of polyenes against fungal pathogens is due to their stronger binding to fungal membrane ergosterols compared to cholesterol present in human and animal cell membranes. nystatin (62a), partricin and pimaricin are administered locally, whereas amphotericin b (amb, 63a) is the only polyene that is applied for the treatment of systemic mycoses. unfortunately, polyenes are rather toxic agents because of their low selectivity for fungal versus mammalian cell. poor solubility of polyenes in water, their high hematotoxicity and nephrotoxicity and a number of other adverse effects have stimulated an extensive search for new, less toxic and more effective agents. previously, it was shown that toxicity of compound 63a and other polyenes can be reduced by chemical modification, which leads to a decrease in side effects. 44, 45 the toxic effect of compound 63a on blood cells (haemolysis) is particularly dangerous. in order to improve antifungal properties, cytotoxic and therapeutic characteristics and to study the mechanisms of action, series of new semi-synthetic derivatives based on amb (63a) and bioengineered analogues s44hp (64a), bsg005 (65a), bsg022 (66a), bsg019 (67), bsg003 (68a) and bsg018 (69) were synthesized (in collaboration with the company biosergen, norway) (scheme 17). 46 ± 49 the structural diversity of the above-mentioned polyenes 64a ± 66a, 67, 68a and 69 was provided by using methods of genetic engineering to alter genes encoding the nystatin-producing strain streptomyces noursei. 50 new analogues compare favourably with nystatin (62a), primarily due to the presence of a double bond (instead of a single one) at c(28) ± c(29) characteristic of 63a and other polyenes 64 ± 69. the heptaene group of the aglycone imparts rigidity to the antibiotic structure and improves antifungal activity. new monosubstituted polyene macrolides at the terminal 16-co 2 h group of the aglycone were synthesized based on compounds 63a and 64a; monosubstituted polyene macrolides at the mycosamine 3 h -amino group were prepared based on 63a, 64a and 65a. 47, 48 the synthesis of doubly modified analogues of antibiotics 63a and 64a was reported. 48 the related amido derivatives (64b ± 64h) substituted in a similar way at the c(16)-carboxamide group of s44hp were prepared. 46 ± 49 the yields of c(16)-amido derivatives were *50% ± 90% depending on the structure of the starting amine and the antibiotic. the antibiotic structure was found to have almost no effect on antifungal activity against the fungal strains candida albicans (atcc 14053), cryptococcus humicolus (atcc 9949), aspergillus niger (atcc 16404) and fusarium oxysporum (vkm f-140). the activity in each pair of the derivatives containing the same substituents is almost the same in magnitude. carboxamides 63b,d,g and 64b,e,i were found to be the most effective against the above-mentioned strains (mic 50 & 0.5 ± 2 mg ml 71 ). the major directions of chemical modification of s44hp (64a) and bsg005 (65a) at the mycosamine 3 h -amino group in alkylation and aminoacylation reactions, the aminocontaining reagents are protected by the 9-fluorenylmethoxycarbonyl (fmoc) group. conventional 3 h -n-alkyl derivatives of polyenes, such as the 3 h -n-(4-dimethylaminobenzyl)-substituted compounds s44hp (64l) and bsg005 (65c) and the n,n-di(aminopropyl)-substituted compounds s44hp (64m) and bsg005 (65d), were synthesized by reductive alkylation of compounds 64a and 65a with appropriate aldehydes in the presence of nacnbh 3 (see scheme 19, conditions b and c). 47 the yields of compounds 64m and 65d with respect to the starting antibiotics are *12% ± 20%. 3 h -n-acyl derivatives 64n and 65e were synthesized by the reaction of antibiotics 64a and 65a with n a ,n e -(fmoc) 2 -l-lysine in the presence of pybop in *71% ± 74% yields (see scheme 19, conditions d ). the removal of the fmoc group from intermediate derivatives 64o,p and 65f,g with a 5% piperidine solution in dmso 47 affords the corresponding 3 h -n-aminoacyl derivatives 64m,n and 65d,e in *11% ± 20% yields. the evaluation of the influence of substituents in the terminal group at the c(16) atom of the aglycone and the mycosamine amino group on the antifungal activity of polyenes showed that the replacement of the co 2 h group by me has no significant effect on antifungal activity against the tested strains. 48 the activity of s44hp (64a) and its analogue 64k is similar to that of bsg005 (65c) and its analogue 65b. thus, the effect of the same modifications on the activity of the initial antibiotics s44hp and bsg005 with very close values of antifungal activity can be multidirectional. the mic 50 values are changed in the following series: 64a = 65a, 64k = 65b, 64l > 65c, 64m > 65d, 64n < 65e. (77) . the removal of the fmoc protecting group from compound 72a gave 3 h -n-(l-lysyl)-s44hp n-(3-dimethylaminopropyl)amide (72b). 49 an alternative scheme involves the initial synthesis of fmoc-protected 3 h -n-aminoacyl derivatives of s44hp followed by their transformation into the corresponding c(16)-carboxamides (scheme 21). the reaction of compound 64a with n-fmoc-4-aminomethylbenzoic acid in the presence of pybop affords 3 h -n-(n-fmoc-4-aminomethylbenzoyl)-s44hp (78) . the amidation of the latter with appropriate amines in the presence of pybop gives 3 h -n-(n-fmoc-4-aminomethylbenzoyl)-s44hp dmae-amide (79a) and 3-hydroxypropylamide (80a). known compound 64p, which was prepared by the reaction of 64a with n a ,n e -(fmoc) 2 -l-lys in the presence of dcc and hobt, was used to synthesize n-(2-dimethylaminoethyl)amide (81a) and 3-hydroxypropylamide (82a) of n a ,n e -(fmoc) 2 -l-lysyl-s44hp. the removal of the fmoc group from compounds 79a ± 82a under mild conditions gave target products 79b ± 82b containing free amino groups (see scheme 21) . 49 the evaluation of antifungal activity of doubly modified s44hp derivatives 70 ± 82 against the above-mentioned four fungal strains compared to the corresponding monomodified s44hp c(16)-carboxamides 64b,c demonstrated that the additional modification of the mycosamine 3 h -amino group of carboxamide 64b has no significant effect on antifungal activity against these fungal and yeast strains (mic *0.5 ± 2 mg ml 71 ). meanwhile, the corresponding modifications of s44hp 3-hydroxypropylamide lead to a considerable decrease in antifungal activity. in the series of doubly modified derivatives, s44hp 2-n,n-dimethylethylamides (73 and 74, respectively), prepared via the amadori rearrangement with d-glucose or d-galactose, exhibit the highest activity, similar to that of the starting antibiotics 63a and 64a. 49 experiments in animals play a significant role in the selection of lead antifungal agents. since only rather toxic amb (63a) is used for the treatment of systemic fungal infections, compounds exhibiting the highest in vitro activity are currently tested for the haemolysis and(or) acute toxicity. new genetically engineered polyene macrolides 64a, 65a, 66a and 68a, the semi-synthetic derivatives dmae-s44hp (64b), 3 h -n-lys-bsg005 (65e) and doubly modified 3 h -n-(1deoxy-d-fructos-1-yl)-s44hp dmae (73) were evaluated for antifungal activity in the treatment of candida albicansinduced sepsis in mice and tested for toxicity. 47, 49 the largest margin between the therapeutic and toxic doses was observed for compounds 64b and 73. compounds, the effective dose was 2% and 6% of the maximum tolerated dose (mtd), respectively, whereas amb (63a) is effective only at a dose of 62% of mtd. the antifungal activity of c(16)-methyl-c(16)-decarboxypolyenes against four fungal strains changes in the following order: bsg005 [c(7), c(10)] (65a) > bsg019 [c(7)] (67) > bsg018 [c(7), c(9)] (69) . 48 this confirms the pattern of changes in the activity against c. albicans observed previously in the series of c(16)-carboxy-containing antibiotics with a similar arrangement of hydroxyl groups at c(7)7c(10): s44hp (64a) > bsg022 (66) [c(7)] > bsg003 (68a) [c(7), c(9)]. 50 the following amides were synthesized from polyenes 64a, 66a and 68a and 2-(n,n-dimethylamino)ethylamine according to the conventional amidation method in the presence of pybop: dmae-s44hp (64b), dmae-bsg022 (66b) and dmae-bsg003 (68b) (see scheme 17) . 47, 48 the activity of these compounds, like that of the starting antibiotics, changes in a similar series: dmae-s44hp (64b) > dmae-bsg022 (66b) > dmpe-bsg003 (68b). it is worth noting that low antifungal activity of compounds 66b and 68b was confirmed also by animal experiments related to the treatment of murine candida sepsis. these studies clearly demonstrated that the c(7)7c(10) group of the polyol moiety plays a critical role in antifungal activity, although this group has not previously been considered of importance in the model of antibiotic binding to the target. compounds containing a single hydroxyl group at the 7 position of c(7)7c(10) (66a and 67) exhibit low activity against the tested fungal strains. polyenes containing two hydroxyl groups at the 7 and 9 positions (68a and 69) are inactive. 48 antibiotics and semi-synthetic derivatives containing hydroxyl groups at the 8 and 9 positions (amb, 63a,b) and at the c(7) and c(10) atoms [s44hp (64a,b) and bsg005 (65a,b)] displayed the best results. the design of hybrid analogues of antibiotics containing pharmacophore moieties, which affect targets different from those used by the starting antibiotics, is a promising line of research. 28, 29 some benzoxaborole-containing compounds exhibit pronounced antifungal activity. 51 methods were developed for the synthesis of dual-action antibiotics based on amb (63a) and different types of benzoxaboroles. the following five types of conjugates were synthesized depending on the nature of the functional group in benzoxaborole, which can be used to attach the latter to the amb molecule: c (16) 3 h -n-sulfo derivative 87 and 3 h -n-mono-and 3 h -n,n-dialkyl derivatives 88a and 89 (scheme 22). 52 amide 83 was produced by the standard procedure that was applied to prepare the above-described amides; however, the yield of 83 was low (10%). apparently, the amidation interferes with the formation of the aminoborole complex with amb. as mentioned above, the yields of amb carboxamides in this reaction using other amines are higher than 50%. 3 h -n-derivatives 84a ± 86a were prepared from amb (63a) using in situ generated osu-activated esters. 3 h -n-sulfo derivative 87 was synthesized by the reaction of 63a with the appropriate sulfochloride in the presence of pyridine (py); 3 h -n-alkyl analogues 88a and 89 were prepared by the reaction of 63a with the appropriate aldehyde in the presence of nabh 3 cn. 52 the amidation of derivatives 84a and 87a with n,n-dimethylethylenediamine in the presence of pybop gave 84b and 87b, respectively (scheme 23). an attempt to synthesize disubstituted 3 h -n-alkyl-dmae analogue 88b according to a similar scheme from 3 h -n-alkylamino derivative 88a failed (see scheme 22) . 50 nevertheless, compound 88b was prepared using an alternative approach by the alkylation of c(16)-amide derivative 63b with 1-hydroxy-1,3-dihydrobenzo[c] [1, 2] oxaborole-6-carbaldehyde in the presence of nabh 3 cn (see scheme 23). 52 tandem mass spectrometry (esi-ms/ms-mrm) studies showed that different fragmentation patterns are possible depending on the modification of the starting polyene (scheme 24). 52 in many cases, the introduction of the benzoxaborole substituent leads to a decrease in cytotoxicity and haemolytic activity with retention of high antifungal activity. these facts were confirmed by membrane activity assays. 53 the results are given in table 1 . semi-synthetic amb derivatives 63b,d,e, 84a,b, 85a, 87b and 88a,b were shown to have a significant pore-forming ability in artificially formed sterol-containing membranes. 53 compounds with high antifungal activity and low haemolysis have higher selectivity for ergosterol-containing fungal membranes (c chol /c erg ) versus cholesterol-containing human cell membranes compared to compound 63a. for example, the high selectivity (5.4 ae 1.0) of compound 84b correlates with low haemolysis of human erythrocytes (6%). on the contrary, high haemolysis (47%) is determined by low or even reverse selectivity (c chol /c erg = 0.5 ae 0.2). for amb (63a) and its derivative 63b, the corresponding parameters have intermediate values (c chol /c erg = 2.3 ± 2.4, haemolysis 15% ± 23%). 53 amphotericin b (63a) was selectively modified at the mycosamine 3 h -amino group or the c(16) carboxyl group. the developed approaches were extended to the related polyenes s44hp (64a), bsg005 (65) and other genetically engineered polyenes, which differ from the starting amb by the substituent at the c(16) atom and the positions of hydroxyl groups at c(7) ± c(10) of the aglycone moiety. the structure ± activity relationship analysis of new semisynthetic derivatives of polyene macrocycles revealed several general features of antifungal activity. in particular, antibiotics and, consequently, their semi-synthetic analogues containing two hydroxyl groups in this region at the 8 and 9 positions (amb, 63a) or the 7 and 10 positions (s44hp and bsg005) exhibit high activity. a series of new semi-synthetic derivatives were shown to have pore-forming ability in artificially formed sterol-containing membranes. it is worth noting that they have selective activity against ergosterol-containing fungal membranes and lower haemolysis compared to amphotericin b. the aim of chemical modifications of the antibiotic oligomycin a (90a) (fig. 6 ) acting as the f 0 f 1 -atp synthase inhibitor is to prepare new analogues possessing selective antitumour or anti-infective activity and to elucidate the mechanisms of sensitivity of microorganisms to this agent. oligomycin a (90a) (hereinafter oligomycin) belongs to macrolides ð 26-membered a,b-unsubstituted macrolactones. it is a highly specific inhibitor of oxidative phosphorylation in the mitochondria of eukaryotes. oligomycin inhibits adenosine triphosphate (atp) synthesis and causes cell death. note. cerg is the minimum concentration of the compound that causes the pore formation in the dphpc/erg bilayer; cchol/cerg is the ratio of the minimum concentrations of the polyene in the dphpc/chol and dphpc/erg bilayers (dphpc is 1,2-diphytanoyl-sn-glycero-3-phosphocholine, chol is cholesterol, erg is ergosterol). the oligomycin molecule (90a) was found to contain a functional group, the chemical modification of which can produce the largest number of semi-synthetic analogues with various biological activities. the docking study of the interaction between the antibiotic and the target of the enzyme f 0 f 1 -atp synthase showed that the c(32)7c (34) side chain is not directly involved in the formation of this complex. 54 a series of 33-substituted oligomycin derivatives were synthesized using 33-deoxy-o-mesyl oligomycin (91) as the key compound, which was prepared by the selective treatment of 90a with methanesulfonyl chloride in a dmap ± py mixture (scheme 25). 55 the nucleophilic substitution of the group r via the s n 2 or s n 1 mechanism using various reagents gave the following 33-substituted derivatives: 33-(s)-oligomycin a (90b), 56 33-deoxy-33-(s)-thiocyanooligomycin (92), 57 33-deoxy-33-(r,s)-bromooligomycin (93) 58 and 33-deoxy-33-(s)-azidooligomycin (94) 55 (see scheme 25) . the racemization is observed only for 33bromo derivative 93. the 33-epimer of this antibiotic, 33-(s)-oligomycin a (90b), was synthesized by the solvolysis of 33-(r)-deoxy-omesyl oligomycin (91) with an aqueous mixture of tiourea and methyl cellosolve on heating. the reaction involves the walden inversion of configuration at the c(33) atom through a plausible mechanism presented in scheme 25. the biological activity assay of compound 90b revealed that the inversion of the hydroxyl group decreases activity against the actinobacteria streptomyces fradiae, while the antifungal activity remains at the same level. 33-(s)-oligomycin a (90b) exhibits somewhat higher activity against tumour cells compared to the starting analogue 90a. both antibiotics are able to overcome different drug resistance phenotypes and have low toxicity to non-malignant cells. 56 the treatment of oligomycin 91 with 98% formic acid afforded c(33)-o-formyloligomycin (95) 59 (see scheme 25) . formylated derivative 95 retains the ability to inhibit tumour cell growth, whereas the activity against most other test cultures, including non-malignant cells, decreases. due to selectivity against tumour cells, c(33)-o-formyloligomycin (95) holds promise for further investigation. 33-deoxy-o-mesyl oligomycin (91) can be quantitatively converted into 33-dehydrooligomycin (96) by the kornblum oxidation in a dmso ± et 3 n mixture at 105 8c (see scheme 25) . 54 attempts to oxidize the oh group at the c(33) atom of oligomycin (90a) to the keto group using different oxidizing agents failed. the cited study is interesting because this structure was previously presented as a new natural compound. however, the structure of this compound was not described in detail and its biological activity was not evaluated. derivative 96 exhibits twice lower activity against s. fradiae atcc-19609 compared to com pound 90a; its activity against candida spp. and other filamentous fungi is very similar to that of compound 90a. docking studies of the binding of derivative 96 to f 0 f 1 -atp synthase also showed that the affinity for the enzyme decreases compared to the starting antibiotic 90a. 54 a method for the synthesis of 1,4-disubstituted 1,2,3triazoles of oligomycin was developed based on 33-azido-33-deoxyoligomycin 94. the method involves the regioselective [3+2]-dipolar cycloaddition of the 33-azido group to monosubstituted alkynes (scheme 26). 55 the reaction of azide 94 with alkynes (phenylacetylene, propiolic acid and methyl propiolate) in a tert-butanol ± water mixture (1 : 1) can be performed both in the presence of a catalyst (cu i ) or without catalysts. this approach was applied to synthesize 33-deoxy-33-(4-phenyltriazol-1-yl)oligomycin (97), 33-deoxy-33-(4-methoxycarbonyltriazol-1-yl)oligomycin (98) and 33-deoxy-33-(4-carboxytriazol-1-yl)oligomycin (99) in 53%, 52% and 50% yields, respectively. compound 99 served as the starting compound for the synthesis of water-soluble 33-deoxy-33-[(4-dmae-carbonyl)triazol-1yl]oligomycin amide (100) exhibiting selective antitumour activity. 55 oligomycin 90a undergoes a retro-aldol rearrangement accompanied by dehydration in the presence of bases (scheme 27). 60 the structure of alkaline degradation product 101a was established by the detailed 1 h and 13 c nmr study, including heteronuclear correlation, combined with tandem mass spectrometry (esi-ms/ms-mrm). the structure of the carbon skeleton of the starting antibiotic 90a undergoes a significant transformation at c(7)7c(12) (the cleavage pathways a, b and c) giving open-ring compound 101a. the mechanism of alkaline degradation of oligomycin 90a presented in scheme 27 accounts for the formation of derivative 101a (through intermediates 90c,d) but not for the formation of 101b (through intermediates 90e,f). 61 as opposed to compound 90a, compound 101a does not exhibit activity against proteasomal f 0 f 1 -atp synthase at a concentration of 1 mmol l 71 because of the loss of conformational rigidity. the hydrogenation of oligomycin (90a) on a palladium catalyst occurs both at the 2,3-unsaturated bond of lactone and the diene system at c (16) the hydrogenation of compound 90a under other conditions leads to the sequential selective reduction of keto groups ð first at the c(7) atom and then at the c(11) atom. thus, the use of nabh(oac) 3 latter with nabh 4 in ethanol afforded (7s,11r)-tetrahydrooligomycin (104) (see scheme 28) . 59 the hydrogenation of double bonds of the macrolactone ring causes a decrease in the activity of compound 90a both against actinobacteria and fungal and mammalian cells. 62 this may be attributed to the loss of conformational rigidity and the fact that the geometry of the macrocycle favourable for the interaction with the target (f 0 f 1 -atp synthase) is changed because of destruction of the diene system of the starting antibiotic 90a. the retention of activity of the starting compound 102 against some strains of candida spp. supports the previous suggestion that there are additional targets in yeast cells of this genus, the binding to which is apparently independent of the geometry of the macrocycle. the reaction of compound 90a with m-chloroperoxybenzoic acid (m-cpba) in dichloromethane on decreasing the reaction temperature to 717 8c allows the selective epoxidation of oligomycin at one of c = c bonds to form unstable intermediate epoxide 105 (scheme 29). 59 in the presence of formic acid, the latter compound gives a stable disubstituted oligomycin derivative ð 16,17-dihydro-16s,17s-dihydroxy-16,33-diformyloligomycin (106). previously, 16-bromo derivative 107 of this antibiotic was synthesized using n-bromosuccinimide as the brominating agent (see scheme 29). 63 the addition of hydroxylamine and related compounds to 90a was studied. 64 the comprehensive study of the resulting compound by 1 h and 13 c nmr spectroscopy, including heteronuclear correlation, made it possible to establish the structure of nitrone 108a and exclude the possible existence of isomer 108b. it was found that an additional ring involving the c(3) ± c(7) atoms is formed, the activity of the antibiotic against f 0 f 1 -atp synthase being reduced. the reaction of antibiotic 90a with aminopyridinium and 4-dimethylaminopyridinium iodides in pyridine affords cyclic derivatives of pyrazolo [1,5-a] pyridine and 4-methylpyrazolo[1,5-a]pyridine 109a,b, respectively, annulated to the macrocycle (see scheme 30) . 64 their structures were established by 1 h and 13 c nmr spectroscopy, including heteronuclear correlation, and structure 109c was excluded. biological assays of new derivatives of oligomycin (90a) demonstrated that, in most cases, modifications reduce biological activity of the starting antibiotic against s. fradiae. 54, 65 ± 67 the growth inhibition assay of the strain s. fradiae atcc 19609 sensitive to very low concentrations of oligomycin (<0.001 nmol ml 71 or 0.0005 nmol per disc surface) and hypersensitive to most of the known antibiotics was used to study the mechanism of resistance of microorganisms. 66 mutant strains of this microorganism sensitive to analogues of compounds 92 (ref. 67 ) and 108a, as opposed to the starting antibiotic 90a and other derivatives, were produced under experimental conditions. the results of assays demonstrated that antibiotic 90a has several biotargets. these data confirm the conclusion that both the diene system of the macrocycle and its hydroxypropyl side chain play an important role in biological activity. 65 therefore, the chemical modification of the antibiotic oligomycin (90a), a highly active f 0 f 1 -atp synthase inhibitor, was performed for the first time. more than 20 new semi-synthetic oligomycin derivatives were prepared and the mechanism of their action was studied. analogues with selective antitumour or anti-infective activity were synthesized. the chemical modification of antibiotic 90a, which enables the efficient modulation of its biological activity due to a decrease in the binding to f 0 f 1 -atp synthase, was found. this provides the possibility to optimize pharmacological properties. olivomycin a (110) (hereinafter olivomycin) is a highly effective antibiotic with a unique mechanism of antitumour activity discovered in the gause institute of new antibiotics 6, 68, 69 (fig. 7) . its structure consists of the aglycone olivin and two carbohydrate chains attached to the aglycone at the 2 and 6 positions. the antibiotic is a dna duplex minor groove ligand, which binds to the guanine-cytosine (gc)-rich region. compared to other antibiotics of the aureolic acid group (mithramycin and chromomycin a), olivomycin 110 has better therapeutic efficacy. in recent years, antibiotics of this group have attracted increasing interest. 70, 71 antibiotics of this group were shown to be able to prevent the development of resistance of tumour cells to other antitumour agents, in particular via a mechanism involving the inhibition of transcription of the mdr1 gene, overexpression of which is responsible for multidrug resistance of tumour cells. mithramycin is used to treat paget's disease and testicular carcinoma. chromomycin is a drug of limited use in japan for the treatment of gastrointestinal cancer. olivomycin (110) was applied in the ussr for the treatment of ovarian cancer, reticulosarcoma and some other tumours. however, serious adverse effects limit the therapeutic potential of these drugs. various aspects of antitumour activity of antibiotics of the aureolic acid group were addressed in detail; however, chemical modifications of this class of antibiotics are poorly known. selective modifications of olivomycin (110) at the c(5) atom (a), the c(8)7oh (b) and c(2 h ) = o groups (c), the c(2 h )7c(3 h ) bond (d ) and the residues a4 and e4 (e) (see fig. 7 ) were developed in the gause institute of new antibiotics. the selective acylation of compound 110 at the phenolic hydroxyl group at the c(8) atom with a ac 2 o7py mixture affords 8-o-acetylolivomycin (111) (scheme 31). 72 an investigation of the reaction of olivomycin (110) with aryldiazonium salts showed that the azo coupling gives aryldiazenes monosubstituted at the 5 position of the aglycone accompanied by the elimination of the disaccharide branch at the c(6) atom: 5-(phenyldiazenyl)olivomycin (112), 5-(4-sulfamidophenyldiazenyl)olivomycin (113), 5-(4methoxyphenyldiazenyl)olivomycin (114), 5-(3,4-dichlorophenyldiazenyl)olivomycin (115) and 5-(4-methylphenyldiazenyl)olivomycin (116) (see scheme 31) . 72 to explain the outcome of this reaction, the frontier electron density in the highest occupied molecular orbital (homo) was calculated by the semiempirical quantum chemical am1 method (fukui indices f). alternative directions of the nucleophilic attack by the phenyldiazonium cation were chosen by considering possible anionic forms of olivomycin (110a ± 110c) (scheme 32 a). it was found that the 5 position in anion 110a is the most favourable for electrophilic attack giving compound 112 (the fukui index f homo is 0.617). meanwhile, the nucleophilicities of the c(7) and c(10) atoms are lower (0.356 and 0.185, respectively). the formation of anion 110a in an alkaline medium is confirmed by the above-mentioned selective acylation of compound 110 giving acetate 111 at the same hydroxyl group at the c(8) atom in high yield (see scheme 32) . 72 the calculated energy parameters of alkaline hydrolysis of the disaccharide branch are in agreement with the experimental data. thus, the hydrolysis proceeds very rapidly in the presence of the diazenyl substituent at the 5 position, while the storage of 110 in an alkaline medium (used for the azo coupling) on cooling to 0 ± 5 8c for 2 h in the absence of diazonium salt does not lead to hydrolysis. the azo coupling of aryldiazonium salts with the aglycone of olivomycin ð olivin (117), which was synthesized by quantitative acid hydrolysis of compound 110, was investigated. aryldiazenyl derivatives of olivin 117a ± c containing the same substituents as compounds 112, 114 and 115 (scheme 33) were synthesized. 70 the geometric configurations of the most probable tautomeric structures a ± d of derivative 117a were determined (scheme 34) and the total energies of each tautomeric form were calculated by the density functional theory at the b3lyp/6-31g(d) level of theory. the 1 h nmr spectroscopic data also indicate that compounds 117a ± c exist as equilibrium mixtures of isomeric forms a ± d. the reaction of olivomycin (110) with (o-carboxymethyl)hydroxylamine affords 2 h -(carboxymethoxime)olivomycin (cm) 118 (scheme 35). 74 the introduction of the carboxyl group into molecule 110 makes it possible to subject this compound to further modification. the reaction of compound 118 with appro75 the introduction of the carboxyl group into molecule 110, as in the case of long acid 118, provides a route to its further modification. the reaction of short osa 124 with appropriate amines in the presence of pybop or diphenylphosphoryl azide (dppa) affords osa n-methylamide it is worth noting that the method developed for the synthesis of intermediate osa (124) can be applied to prepare the related derivative of mithramycin bearing a similar side chain at the c(3) atom of the aglycone. hence, short' mithramycin acid becomes more available compared to the combinatorial biosynthesis and can be used for further chemical modification of mithramycin. 76 olivomycin a (110) has two carbohydrate chains bearing the acetyl group at the a4 position of the oliose moiety and the isobutyryl group at the e4 position of the olivomycose moiety. a series of analogues of compound 110, which differ in the set of functional groups, were synthesized in order to elucidate the influence of acyl substituents in carbohydrate chains on biological activity. 77 two analogues, de-e4-isobutyrylolivomycin a (133) and de-e4-isobutyryl-de-a4-acetylolivomycin a (or de-e4isobutyrylolivomycin c) (134), were synthesized by selective alkaline hydrolysis of the e4-isobutyryl group of olivomycin a (110) or c (135), respectively (scheme 37). it is worth noting that the hydrolysis of the e4-isobutyryl group in olivomycin (110) antibiotics 135 (de-e4-isobutyrylolivomycin a) and 136 (de-e4-isobutyryl-e4-acetyl-olivomycin a or olivomycin b) were isolated from the natural olivomycin complex produced by fermentation of the streptoverticillum cinnamoneum strain. after the purification by silica gel column chromatography and semipreparative hplc, compounds 135 and 136 were isolated in 40% and 45% yields, respectively. 70, 77 these compounds are identical to the previously characterized natural olivomycins c and b, respectively. 78 the modification of antibiotic 110 at the c(8) phenol group of the aromatic ring (compound 111) was found to have no effect on antiproliferative activity against cancer cell lines and does not alter its ability to inhibit topoisomerase i. 72 the transformation of 110 giving diazenyl derivatives accompanied by elimination of the disaccharide branch from the aglycone (compounds 112 ± 116) leads to a sharp decrease in antiproliferative activity. compared to the starting olivomycin 110, compounds 112, 115 and 116 acquire considerable selective activity against human immunodeficiency viruses hiv-1 and hiv-2 in assays in the human t-lymphocyte cell line (cem). 72 the evaluation of antiproliferative activity of olivomycin (110) and its analogues modified at the side-chain 2 h -keto group of the aglycone (cm amides 119 ± 121 and 123) against the leukaemia cell lines k562 and l1210 showed that these compounds are more effective than the starting acid 118 but are less active than compound 110. 74 for derivatives of antibiotic 110 with a shorter aglycone side chain (osa, 124) and its amides 125 ± 132, the evaluation of antiproliferative activity in the human chronic myeloid leukaemia cell line k562 and the human colon 75 the evaluation of antiproliferative activity of olivomycin analogues 133 ± 136 against hct116 cells showed that acyl groups in carbohydrate chains of antibiotic 110 play a significant role. the activity decreases with elimination of acyl groups from molecule 110; ic 50 is 0.02 (for 110), 0.064 (for 136), 0.28 (for 133) and >50 mmol l 71 (for compounds 117, 134 and 135). 77 these results correlate with the data on the ability of these compounds to inhibit dna-dependent topoisomerase i. 79 in the absence of antibiotics, the relaxation of supercoiled (sc) dna leads to the disappearance of inhibitory activity and the formation of a set of topoisomers. the inhibition of topoisomerase i is detected from the presence of residual amounts of sc-dna and a decrease in the amount of rapidly migrating topoisomers. a decrease in the inhibitory activity of the enzyme is consistent with a decrease in the antiproliferative activity in the series of compounds 110 > 136 > 133. the removal of the e4-isobutyryl group from the trisaccharide branch has a lower effect than the removal of the a4-acetyl group from the disaccharide branch. a similar pattern of activity is observed in another group of olivomycin derivatives. compound 118 displays low antiproliferative activity and is inactive against topoisomerase i. 2 h -(carboxymethoxime)olivomycin n-(2-adamantyl)amide (121) is active in both assays. 2 h -(carboxymethoxime)olivomycin n-(tert-butyl)amide (122) and 2 h -(carboxymethoxime)olivomycin n-(1,3-dihydroxy-2-methylpropan-2-yl)amide (123) are even more effective inhibitors of the enzyme, capable of inhibiting sc-dna relaxation even at concentrations of 0.1 mmol l 71 . 74 the data on antiproliferative activity of some analogues of antibiotic 110 do not correlate with the activity against topoisomerase i. for example, the analogue of olivomycin osa (124), which exhibits weak antiproliferative activity, displays inhibitory activity against topoisomerase i similar to that of olivomycin a (110), whereas dmae-osa (127) possessing high antiproliferative activity is a weaker inhibitor of this enzyme. 74, 79 recently, it was shown that highly effective analogue 127 can act as a dna duplex minor groove ligand in another assay. it can disrupt the key epigenetic dna methylation process with the dnmt3a enzyme on an equal basis with antibiotic 110. both compounds inhibit the formation of the dna ± enzyme7intermediate covalent bond, required for the methylation, at nearly equal micromolar concentrations. 80 olivomycin complexes with model oligonucleotide ± dna duplexes were studied by circular dichroism (cd) and fluorescence titration (ft). according to hartree ± fock 3-21g calculations of the 3d structure of the dimer [110] 2 mg 2+ , the presence of the dmae group in compound 127 leads to an increase in the binding constant (k a ) of the mg 2+ complex with the dna duplex by an order of magnitude compared to the acid osa (124) (k a = 1.35610 5 versus 2.1610 4 mol l 71 , as evaluated by ft). however, the presence of the bulky adamantyl substituent in compound 121 results in a decrease in the binding constant of the dimer [121] 2 mg 2+ with the dna duplex by an order of magnitude (k a = 1.32610 4 mol l 71 ). 81 the elimination of one acyl substituent also leads to a decrease in the antiproliferative activity compared to that of antibiotic 110 due probably to a decrease in its affinity for dna. 77 the molecular docking of complex of 110 with dna shows that the antibiotic can bind only to gc-rich regions in the minor groove of the dna duplex. 82 carbohydrate chains of olivomycin interact with the sugar ± phosphate backbone of dna, and the aglycone interacts with nucleic acid bases. the sites of 110 responsible for the interaction with dna (an additional hydrogen bond with the nh 2 group of the g base) and the complexation of the antibiotic with dna were identified. the structural fragment, which is not directly involved in the interaction with dna but models the affinity of the antibiotic to the target ð the minor groove of the dna duplex, was determined. based on these data, a schematic model of the interaction between olivomycin a and dna was proposed (scheme 38). 73 two semi-synthetic olivomycin derivatives (121 and 127) with the modified aglycone side chain were chosen based on the evaluation of antiproliferative activity in animal assays. compound 121 is more effective in the treatment of p388 murine leukaemia than the starting antibiotic 110 due to a decrease in toxicity and the absence of the cumulative effect. 83, 84 compound 127 (olivamide) is also more effective in this assay compared to the starting antibiotic 110. 85 detailed preclinical assays in transplanted syngeneic tumours confirmed the efficacy of the agent based on compound 127 for further clinical trials. 85 ± 88 these studies enabled the development of methods for selective chemical modification of the antibiotic olivomycin a, resulting in the synthesis of a series of semi-synthetic derivatives of this antibiotic; besides, structure ± activity relationship analysis was performed. 70, 73 many of these compounds exhibited high antiproliferative activity in different tumour cell lines. some aspects of the mechanism of action of olivomycin a and its natural and semi-synthetic analogues were considered. 74, 75, 77, 79 ± 82 it was concluded that high antitumour activity of these compounds is related to their high affinity to the dna duplex. based on the results of in vitro assays, compounds were chosen for the evaluation of antitumour activity in in vivo assays. after the preclinical evaluation of antitumour activity and toxicity in laboratory animals, semi-synthetic olivomycin analogue 127 ð olivamide ð was recommended for further clinical trials. 85 ± 89 anthracycline antibiotics are important chemotherapeutic agents commonly used in the treatment of malignant tumours. daunorubicin (137a), which was independently discovered under the name of rubomycin in the gause institute of new antibiotics (gina), 6 is applied mainly for the treatment of leukaemia in children and adults. doxorubicin (14-hydroxydaunorubicin, dox) (138a) is used in combination chemotherapy of breast cancer, smallcell lung cancer, sarcoma, tumours in children and haemoblastosis. an original method for the one-pot preparation of semi-synthetic doxorubicin from rubomycin was developed in the gina. 6 carminomycin (139a), which was also discovered in the gina, has lower cardiotoxicity than other anthracyclines and can inhibit the growth of doxorubicin-resistant tumours (138a). 90 the structures of anthracycline antibiotics 137a, 138a and 139a are shown in fig. 8 . the mechanism of cytotoxic activity of anthracycline antibiotics is related mainly to the inhibition of nucleic acid synthesis via intercalation between nitrogeneous base pairs, dna damage and inhibition of dna topoisomerases. an adverse effect of anthracyclines is the potentially irreversible and cumulative dose-related cardiotoxicity, apparently associated with the free-radical damage of myocardial cell membranes. the chemical modification of anthracycline antibiotics was extensively studied in the gina for a long period of time. in recent years, efforts were focused on the synthesis of new semi-synthetic analogues of drugs with improved anticancer properties. 91 daunorubicim (137a) and carminomycin (139a) were modified at the c(14) atom (b), the c(13) = o bond (c) and the daunosamine 3 h -amino group (d, e) (see fig. 8 ). 3 h -n-alkyl or 3 h -n-aminoacyl derivatives exhibit high antitumour activity, because they retain the amine function at the daunosamine moiety. 90 this function is required for the primary interaction of the antibiotic with the sugar ± phosphate backbone of dna. however, the drawback of reductive alkylation of anthracyclines 137a and 139a with aldehydes in the presence of nabh 3 cn is that it is accompanied by the reduction of the c(13) = o group as the side reaction giving n-alkyl-13-dihydro derivatives of daunorubicin (137b) and carminomycin (139b), respectively (scheme 39). these analogues are less active than the related compounds containing the c(13) = o group. 92 ± 94 13-dimethyl ketals of 14-bromo derivatives of daunorubicin (137c) and carminomycin (139c) were used to avoid this side reaction (see scheme 39) . the reductive alkylation of compounds 137c and 139c in the presence of nabh 3 cn can be accomplished using d,lglyceraldehyde and aldoses (the monosaccharide arabinose and the disaccharide melibiose) to form the following 14bromo-substituted 13-dimethyl ketals in quantitative yields: the antiproliferative activity of compounds 139e and 143 against leukaemia cells k562 is virtually as high as that of derivative 137e, but is lower than that of carminomycin (139a). the activity of 14-hydroxycarminomycin derivative 143 evaluated in the same assay is an order of magnitude lower than that of the starting anthracycline 139a, and the activity of doxorubicin 137e is two orders of magnitude lower than that of compound 138a. it should be emphasized that 14-hydroxycarminomycin derivatives 142 and 143 are equally active against the wildtype human breast adenocarcinoma cell lines mcf-7 and k562 and resistant pgp-expressing cell lines (mcf-7dox, k562i/s9). the antitumour activity of compound 139e evaluated in the murine leukaemia cell line p388 compares favourably with that of analogue 138a. thus, an increase in life span (ils) of mice bearing p388 leukaemia after a single admin-istration of 10 mg kg 71 of compound 139e is the same as that observed after administration of analogue 138a at a dose of 8 mg kg 71 (ils 108%). 92 it was shown that anthracycline antibiotics 137a, 138a and 139a, which are known to inhibit dna topoisomerase ii at micromolar concentrations, can inhibit dna topoisomerase i at the same concentrations. 75 new derivatives 137e, 139e, 142 and 143 have higher inhibitory activity against topoisomerase i compared to compounds 138a and 139a. the introduction of polyhydroxylated substituents at the 3 h -amino group of the daunosamine moiety of anthracycline antibiotics increases the inhibitory activity of anthracyclines against topoisomerase a method was developed for the preparation of new watersoluble depot forms of doxorubicin (138a) ð conjugates with high-molecular-mass polysaccharides. 95, 96 galactomannan davanat (144) was used as the polysaccharide. the latter was prepared by controlled partial hydrolysis of water-insoluble high-molecular-mass 1,4-b-d-galactomannan isolated from seeds of cyamopsis tetragonoloba or guar gum. the molecular mass of compound 144, determined by gel chromatography on a sephadex g-200 column calibrated with pullulans, is *92 kda. to conjugate compound 144 with 138a, the former is activated by the oxidation with periodate using a deficient amount of the oxidizing agent (0.07 ± 0.11 equiv. with respect to the total amount of sugar residues). this gives rise to schiff bases between the aldehyde groups of the oxidized polysaccharide (145a ± 145c) and the 3 h -amino group of the antibiotic (scheme 40). different structures of the final products are possible (146a ± 146c). the content of the starting antibiotic 138a in conjugate 146 is 5 mass % (determined from the content of the chromophore per unit mass of the dried powder by uv spectroscopy at 490 nm). in order to increase the doxorubicin content in the conjugate with davanat 145, the antibiotic molecule was attached to the polysaccharide through a spacer giving 3 h -n-l-lysyldoxorubicin (147) (scheme 41). 96 compound 147 contains two amino groups (while doxorubicin contains one amino group), which may facilitate the formation of the schiff base. besides, it is known that a series of n-acyl conjugates of daunorubicin or doxorubicin with amino acids possess high antitumour activity. 90 3 h -n-l-lysyldoxorubicin (147) was synthesized by the acylation of the amino group of doxorubicin (138a) with n a ,n e -(fmoc) 2 -l-lysine osu-ester followed by the deprotection of the fmoc-protected intermediate with a morpholine solution. 96 the schiff base in the resulting conjugate can have either a linear (148a) or cyclic structure (148b). scheme 41 presents the possible structures for one of the oxidized subunits of activated davanat 145. it should be noted that 3 h -n-l-lysyldoxorubicin can be attached to conjugate 145 through either the a-amino-or e-amino group of 3 h -n-l-lysyldoxorubicin (is not shown in scheme 41). the introduction of the lysine spacer between compounds 138a and 145 allows an increase in the antibiotic content in the conjugate to 10 mass % with retention of water solubility. the conjugates were purified by gel chromatography on a sephadex g-200 column and dialysis against deionized water using a membrane with molecular weight cut-off (mwco) m w > 15 kda. the molecular masses of conjugates 146 and 148 evaluated by gel chromatography on a sephadex g-200 column calibrated with pullulan standards are * 95 and * 98 kda, respectively. the antiproliferative activity of the doxorubicin conjugates was tested in three tumour cell lines: the murine melanoma cell line b16-f1, the breast cancer cell line mcf-7 and the colon cancer cell line ht-29 (htb-38). 96 the ic 50 values for conjugate 146 (taking into account the percentage of antibiotic 138a in the conjugate) are 0.025 ± 0.04, 0.15 ± 0.22 and 0.65 ± 1 mg ml 71 , respectively; for antibiotic 138a, 0.01 ± 0.02, 0.08 ± 0.12 and 0.2 ± 0.3 mg ml 71 . despite the fact that the cytotoxicity of conjugate 146 is *1 ± 2 orders of magnitude lower (data were not reported) than that of doxorubicin (138a), these results indicate that conjugate 146 is an active depot form of doxorubicin (138a). the antiproliferative activity of the 3 h -n-l-lysyldoxorubicin ± davanat conjugate (148) (ic 50 > 50 mg ml 71 ) against these tumour cell lines is much lower compared to cytotoxicity of conjugate 146. this can be due to the fact that the imine bonds in the 3 h -n-l-lysyldoxorubicin ± da-vanat conjugate (148) are more stable than those in conjugate 146. it should be noted that 3 h -n-l-lysyldoxorubicin is not released in in vitro assays. therefore, a biological model, which would provide release of 147, is apparently required to evaluate the therapeutic potential of conjugate 148. based on these studies, a method was developed for the introduction of polyhydroxylated substituents of different types and different length into anthracycline antibiotics, which was used to synthesize a series of new hydrophilic 3 h -n-alkyl derivatives of doxorubicin and 14-hydroxycarminomycin, including those containing mono-and disaccharide residues. 92, 93 this modification was found to enhance the inhibitory activity of anthracyclines against topoisomerase i with retention of antitumour activity of the antibiotics. the new 14-hydroxycarminomycin derivatives, unlike doxorubicin derivatives, were shown to suppress the tumour cell growth insensitive to doxorubicin. 93 a new water-soluble depot form of doxorubicin ð a conjugate with the highmolecular-mass polysaccharide galactomannan dava-nat ð was prepared. 94, 95 this depot form exhibits antiproliferative activity against the above-mentioned three tumour cell lines. 91 the antibiotic heliomycin (resistomycin, 3,5,7,10-tetrahydroxy-1,1,9-trimethyl-1h-benzo[cd ]pyrene-2,6-dione) (149) with a broad spectrum of biological activity (scheme 42) was discovered in the gause institute of new antibiotics. 6 first of all, this antibiotic is highly effective against grampositive and some gram-negative microorganisms, including drug-resistant strains. more recently, heliomycin was found to exhibit antifungal 97 and antiviral (anti-hiv) activity. 98 besides, compound 149 can block proliferation of some tumour cells in in vitro assays. 99 in the soviet union, heliomycin (149) was produced on a commercial scale and was used as a gel for topical treatment of skin infections and healing of burn wounds. the chemical modification of heliomycin is poorly known. hence, structure ± activity relationship studies require the development of method for the synthesis of new semi-synthetic derivatives and evaluation of their biological properties. the main goal is to prepare series of derivatives with improved water solubility in order to expand their practical application. a method was developed for the synthesis of aminomethyl derivatives 149 at the 4 position of compounds 150 (where x is an amine moiety or a nitrogen-containing heterocycle). typical synthetic procedures are presented in relation to compounds 150a ± c (see scheme 42) . 100, 101 the mannich aminomethylation of compound 149 can be performed using amines and formaldehyde in dmf (see scheme 42 b ). an alternative procedure for the synthesis of derivatives 150 is based on the use of pre-prepared stable iminium salts (see scheme 42, conditions a). in the case of aminomethylation of compounds 149 with polyfunctional amines, the amino group is protected with boc (see scheme 42 c) and then deprotected with acid (see scheme 42 d ). the reaction of compound 149 with n,n-dimethylamino(methylene)ammonium chloride afforded 4-[(n,n-dimethylamino)methyl]-3,5,7,10-tetrahydroxy-1,1,9-trimethyl-1-h-benzo[cd ]pyrene-2,6-dione hydrochloride (150a). 100 4-[(tert-butylamino)methyl]-3,5,7,10-tetrahydroxy-1,1,9-trimethyl-1h-benzo[cd ]pyrene-2,6-dione hydrochloride (150b) is produced by the treatment of compound 149 with tertbutylmethylamine in the presence of formaldehyde. the treatment of compound 149 with tert-butylpiperidin-4-ylcarbamate in the presence of a formaldehyde solution gives 4-(4-boc-aminopiperidinomethyl)-3,5,7,10-tetrahydroxy-1,1,9-trimethyl-1h-benzo[cd ]pyrene-2,6-dione, which is quantitatively converted to the corresponding amine dihydrochloride (150c) upon the treatment with hcl7meoh. the antiproliferative activity (ic 50 ) was evaluated by the colorimetric determination of cell metabolic activity (mtt assay) using a standard procedure in eight tumour cell lines, including both drug-sensitive and drug-resistant cell lines. 100 the resulting compounds inhibit tumour cell proliferation in a low submicromolar to micromolar concentration range, similar to that of doxorubicin (138a). however, most of these compounds significantly outperform doxorubicin in terms of the drug-resistance index. these compounds block the growth of the wild-type cell lines k562 and hct116 and the following multidrugresistant cell lines: the k562/4 subline isogenic to p-glycoprotein (pgp)-positive multidrug resistance and the hct116p53ko subline with p53 gene deletion. the development of multidrug resistance in these tumour cell lines is the crucial factor responsible for a decrease in activity of antitumour drugs. as opposed to compound 149, derivatives 150a ± c show a high level of induced apoptosis in the t24 bladder cancer cell line model. the introduction of the 4-aminomethyl moiety enhances the dna-binding affinity and the inhibitory activity against dna topoisomerase i. hence, compound 150c is the most promising candidate for preclinical trials. based on these studies, methods were developed for chemical modification of heliomycin (149). series of new analogues, water-soluble salts of amino-containing derivatives, were synthesized and they were shown to exhibit high antiproliferative activity against many tumour cell lines and inhibitory activity against various targets. 100 the value of these studies is that the majority of aminomethyl derivatives of heliomycin are active against both wild-type and drugresistant cancer cells at micromolar or submicromolar concentrations. the development of new-generation drugs is a challenging problem because of the increasing risk of the development of drug resistance in microorganisms. different approaches to the search for new compounds were developed in recent years. particular attention is given to semi-synthetic derivatives based on available natural antibiotics, since there are numerous examples of the successful application of this approach. some semi-synthetic derivatives based on macrocyclic glycopeptides have advantages over the gold standard chemotherapeutic agent ð vancomycin. 3, 7, 10 the distinguishing features of new representatives of this class are selectivity against multidrug-resistant pathogenic bacteria and higher bioavailability. the new semi-synthetic vancomycin analogue telavancin (vibativ) (manufactured by theravance and astellas pharma, us) was approved for use in the united states and europe. two semi-synthetic derivatives of glycopeptide antibiotics have completed phase 3 clinical trials and were approved by the united state food and drug administration (fda): chloroeremomycin (discovered by eli lilly, acquired by the medicine co in 2009) and dalbavancin (discovered by lepetit; acquired by pfizer in 2005). 8, 10 the drawbacks of vancomycin are the poor accumulation within tissues, because of which it is not used in the treatment of, for example, pneumonia, and a pronounced pseudoallergic reaction typical of glycopeptides. research in international cooperation showed the promise of chemical transformations of the antibiotic eremomycin belonging to this group of glycopeptide antibiotics. eremomycin is a highly active domestic antibiotic that suppresses the growth of gram-positive organisms; it is 3 ± 5 times more effective than vancomycin but is inactive against drug-resistant strains of staphylococci and enterococci. 6 original approaches and methods were developed under the supervision of professor m.n.preobrazhenskaya in the gause institute of new antibiotics. these methods can be applied to prepare derivatives of antibiotics of this group with desired properties. in 2006, the method for the synthesis of glycopeptide analogues was protected by an international patent. 18 promising analogues, various n h -derivatives and carboxamides of eremomycin, were synthesized. these derivatives compare favourably in efficacy against drug-sensitive and drug-resistant strains of staphylococci and enterococci with the related vancomycin derivatives and they are even more effective in a number of assays. 12 ± 15 some carboxamides show no allergenicity. 13 other derivatives (e.g., the adamantane derivative of eremomycin) are promising as a protection against biological risks because they were found to be active against the bacterium bacillus anthracis, including fluoroquinolone-resistant strains. 15 high activity of the resulting hydrophobic glycopeptide derivatives can be attributed to the dual mechanism of action on gram-positive bacteria. 20, 21 modifications of aglycones of glycopeptide antibiotics with hydrophobic substituents resulted in the discovery of a new class of polycyclic peptides active against a large group of enveloped viruses, such as hiv 23 or hepatitis c virus. 25 studies on the mechanisms of antiviral activity are currently ongoing. it was suggested that protein kinase is one of possible targets for this agluco analogue, because antiviral activity was shown to correlate with the inhibition of serine/ threonine protein kinases. 27 comprehensive research on the synthesis and characterization of heterodimeric conjugates based on different classes of antibiotics was initiated in the gause institute of new antibiotics under the supervision of professor m.n.preobrazhenskaya. the following hybrid antibiotics were synthesized: glycopeptide ± macrolide, glycopeptide ± aminoglycoside and hybrid compounds containing the benzoxaborole chromophore. the literature data provide evidence that this line of research holds promise. 28, 29 macrolides modified through the carbamoyl group at the 4 hh position can acquire activity against drug-resistant bacterial cell lines. generally, conjugates containing a long spacer exhibit higher activity than the related compounds with a shorter spacer. 40, 41 investigations of interactions between different benzoxaboroles and antibiotics made a significant contribution to the chemistry of not only antibiotics with complex structures but also the relatively poorly studied borole compounds. benzoxaboroles were found to be quite stable under different reaction conditions. in particular, the acylation, amidation and reductive alkylation with reactive agents and on heating are virtually not accompanied by oxaborole ring opening. 32 the introduction of the benzoxaborole substituent into the polyene macrolide amphotericin b (amb) also enhances biological activity. the resulting compounds possess valuable properties, such as lower cytotoxic and haemolytic activity compared to amb combined with high antifungal activity. 52 the efficiency of the approach to the design of antibiotics of a new generation was demonstrated in relation to antifungal polyene macrolides. it is based on a combination of genetic engineering techniques and methods of organic synthesis 48 ± 50 and is protected by an international patent. 46 the chemical modification of polyene antibiotics, which were obtained via the genetic engineering of nystatin a1 biosynthesis at the norwegian university, gave a series of agents exhibiting lower toxicity and higher activity compared to amphotericin b in animal assays. the dependence of antifungal activity on the structure of the polyol region [c(7) ± c(10)] of these antibiotics was revealed for the first time by preobrazhenskaya et al. 49 pioneering studies on the development of methods for selective chemical modification of the unique macrolactone oligomycin a, a specific f 0 f 1 -atp synthase inhibitor, and the original antitumour antibiotic olivomycin a of the aureolic acid group were performed. in both cases, examples of chemical modifications of related compounds for these antibiotics are absent in the literature. these results are of great scientific value. investigations of f 0 f 1 -atp synthase inhibitors are of considerable interest because this enzyme is involved in the development of resistance in microorganisms. chemical transformations of oligomycin a using different reagents were studied in detail. alkaline hydrolysis reactions were performed and conditions for the selective reduction of double bonds and keto groups, cyclization, etc. were found. the replacement of the c(33)-hydroxyl group by the activated mesyl group has proved to be particularly successful. 55 this modification has no significant effect on biological activity of the antibiotic but provides a possibility to optimize its pharmacological properties. 65, 67 only transformations via the biosynthesis were described for the aureolic acid group antibiotics mithramycin and chromomycin. 70, 76 these natural antibiotics, which have a limited use in the treatment of some malignant tumours, have attracted increasing attention of researchers in different fields. 71, 73 the synthesized compounds were tested for antiproliferative activity. based on the results of in vitro studies of a series of new olivomycin a analogues of different types, compounds were selected for the in vivo evaluation. after preclinical trials in laboratory animals (evaluatrion of antitumour activity and toxicity), one olivomycin a analogue was recommended for further clinical trials. 87 ± 89 a systemic approach applied to series of new semisynthetic analogues of olivomycin a allows a detailed study of the molecular mechanism of antitumour action of this antibiotic. 79 ± 81 in particular, it was shown that olivomycin and its analogues, acting as dna duplex minor groove ligands, can inhibit topoisomerase i and the dnmt3a enzyme responsible for the disruption of the key epigenetic dna methylation process. 79, 80 the structural fragments of olivomycin a critical for antitumour activity were identified. a model of the interaction of the antibiotic and some its analogues with the dna duplex was proposed. 82 new analogues of anthracycline antibiotics with substituents of different types and different length, including those containing mono-and disaccharide residues, were prepared. the evaluation of the effect of polyhydroxylated moieties of doxorubicin and 14-hydroxycarminomycin on antitumour activity showed that this modification does not lead to the loss of activity of anthracyclines 93 ± 95 and enhances inhibitory activity against topoisomerase i. 92 14-hydroxycarminomycin derivatives proved to be particularly valuable because these compounds, as opposed to related doxorubicin derivatives, inhibit the proliferation of both doxorubicin-sensitive and doxorubicin-resistant tumour cell lines. 96 a new water-soluble depot form of doxorubicin with the high-molecular-mass polysaccharide galactomannan davanat was constructed and it was shown that it exhibits antiproliferative activity against three tumour cell lines. 94, 95 series of new heliomycin analogues ð water-soluble salts of amino derivatives ð were synthesized and these compounds were shown to have high antiproliferative activity against many tumour cell lines and inhibitory activity against different targets. 100 the value of these studies is that the majority of aminomethyl derivatives of heliomycin are active against both wild-type and drugresistant cancer cells at micromolar or submicromolar concentrations. the method is protected by a patent. 101 targeted chemical modifications of antibiotics are not only performed in order to prepare new potential drugs of a new generation but are used as an efficient tool for investigation of the mechanisms of action on bacterial or tumour cells. it should be emphasized that many potent antibiotics are indispensable tools for molecular biology research of the living world. such comprehensive studies can lead to the design and synthesis of new-generation drugs, which would be more effective than the starting antibiotics and which are of theoretical interest as new compounds with high biological activity. figures 2, 3 , 5 and 6 were composed by the authors based on the cited publications (the references are given in the figure captions). new approaches to natural anticancer drugs. springer briefs in pharmaceutical science and drug development antibiotics: challenges, mechanisms, opportunities markovnikov congress on organic chemistry (book of abstracts) handbook of experimental pharmacology doctoral thesis in chemical sciences, m.v.lomonosov institute of fine chemical technology glycobiology and drug design. (acs symp. ser. 1102) carbohydrates and drug design. (asc symp. ser. 932) key: cord-339227-2i9q9c8u authors: djakpo, odilon; yao, weirong title: rhus chinensis and galla chinensis – folklore to modern evidence: review date: 2010-11-22 journal: phytother res doi: 10.1002/ptr.3215 sha: doc_id: 339227 cord_uid: 2i9q9c8u the species rhus chinensis mill. (anacardiaceae) is an important representative of the genus rhus, which contains over 250 individual species found in temperate and tropical regions worldwide. rhus chinensis has long been used by folk medicine practitioners in asia. leaves, roots, stem, bark, fruit and particularly the galls on rhus chinensis leaves, galla chinensis, are recognized to have preventative and therapeutic effects on different ailments (such as diarrhea, dysentery, rectal and intestinal cancer, diabetes mellitus, sepsis, oral diseases and inflammation). however, it is critical to separate evidence from anecdote. fortunately, recent scientific research has revealed that rhus chinensis compounds possess strong antiviral, antibacterial, anticancer, hepatoprotective, antidiarrheal and antioxidant activities. moreover, compounds isolated from the stem of rhus chinensis significantly suppressed hiv‐1 activity in vitro. compounds from this plant were also found to inhibit enamel demineralization in vitro and enhance remineralization of dental enamel with fluoride. this review highlights claims from traditional and tribal medicinal lore and makes a contemporary summary of phytochemical, biological and pharmacological findings on this plant material. it aims to show that the pharmaceutical potential of this plant deserves closer attention. copyright © 2010 john wiley & sons, ltd. rhus chinensis belongs to the genus rhus and the family anacardiaceae (miller et al., 2001) . commonly called sumac, rhus consists of approximately 250 individual species of fl owering plants, with six species found (four endemics) in china. like most sumacs, rhus chinensis is a dioecious shrub that can reach 8 m in height. it bears odd pinnately compound leaves and creamywhite fl owers. the fruits (drupes) are orange or red in color at maturity and contain one seed (barkley, 1937; miller et al., 2001; tianlu and barfod, 2008) . the species grows in areas with marginal agricultural capacity, and is widely distributed in temperate, subtropical, and tropical regions, including china, japan, malaysia, taiwan and india (rayne and mazza, 2007; ren et al., 2008) . the species rhus chinensis has two distinct varieties, rhus chinensis var. chinensis (syn. rhus (tianlu and barfod, 2008; grin; tropicos) . galla chinensis or galla rhois is the term used to describe the gall caused by the chinese aphid, schlech-tendalia chinensis (bell), on the leaves of rhus chinensis (lee et al., 1997) . this gall is widely used as a separate drug. other species in this genus also produce galls that are considered to have an inferior quality. a plethora of traditional medicine references claim curative power for rhus chinensis, despite its widespread use, many of these claims of effi cacy were not supported by scientifi c evidence, whether for traditional use validation or for drug development endeavors. fortunately, recent scientifi c research on rhus chinensis has revealed promising health benefi ts, including anticancer, antiviral, antimicrobial, antidiarrheal and antiinfl ammatory properties (yang et al., 2005; gu et al., 2007; ahn et al., 1998; chen et al., 2009; kim et al., 2005) . in recent years, the chinese herbal medicine galla chinensis has been discussed widely as a new alternative for carious disease (chu et al., 2007) . so far, no comprehensive review has been compiled from the literature encompassing the effi cacy of this plant. widespread claims of the medicinal effectiveness of various rhus chinensis tree preparations motivated us to bridge the information gap in this area. among rhus species, rhus chinensis and its gall, galla chinensis, have a long history of use by indigenous peoples for medicinal care and others. numerous curative properties are ascribed to different parts of this tree, namely root, bark, stem, leaf, fruit, fl owers, seed and gall ( table 1 ). the leaves and the root are used as depuratives, stimulating blood circulation. its decoction is used in the treatment of hemoptysis, infl ammations, laryngitis, snakebite, stomachache and traumatic fractures (duke and ayensu, 1985; kao, 1988; ouyang et al., 2008) . the ripe fruits of this plant have long been used in asia to treat dysentery and diarrhea, as well as other gastrointestinal disorders (kala, 2005; pradhan and badola, 2008; bose et al., 2008) . the fruit produces a sour juice when boiled with water. this juice, when diluted with water or/and mixed with raw eggs, treats diarrhea and dysentery (pradhan and badola, 2008) . it is used for the treatment of colic (chopra et al., 1986) and also as a food preservative (pradhan and badola, 2008) . the seed is used in the treatment of cough, dysentery, fever, jaundice, malaria and rheumatism (duke and ayensu, 1985; abbasi et al., 2009) . the gall of rhus chinensis has long been considered to possess natural medicinal properties with numerous benefi ts . galla chinensis is used internally for its astringent properties to treat disease such as diarrhea and hemorrhage (duke and ayensu, 1985) . it is a frequent ingredient in polyherbal prescriptions for diabetes mellitus (duke and ayensu, 1985) . it has hemostatic effects, often used to promote clotting following traumatic injuries and to treat burns (yeung, 1985) . it is also used to treat rectal and intestinal cancer, prolapse of the rectum, seminal enuresis and hemorrhoids (yeung, 1985; gao et al., 2000) . in addition to its antiphlogistic and antiseptic uses for treating diseases such as persistent cough, galla chinensis also has antiinfl ammatory properties (tian et al., 2009) . it is also used to counteract ulcers in the mouth and to treat fever and malaria (duke and ayensu, 1985; gao et al., 2000) . phytochemical studies on rhus species have been reported earlier and resulted in the characterization of several compound groups such as fl avonoids (taniguchi et al., 2000; lee et al., 2005; lin et al., 2008) , triterpenoids (kuo, 1991; parveen, 1991; lee et al., 2005) , phenolics (parveen and khan, 1988; lee et al., 2005; ouyang et al., 2008) , tannins (takechi et al., 1985) and aromatic alkanes (kuo et al., 1991; lee et al., 2005; ouyang et al., 2008) . the galls on rhus chinensis leaves are rich in gallotannin (50-70%), a type of hydrolysable tannin (kee and walter, 1999; xiao et al., 2000) . gallotannins from galla chinensis consist of a central glucose core, which is surrounded by several gallic acid units, and further gallic acid units can be attached through depside bonding of additional galloyl residues. structures containing 1 to 14 galloyl residues result from such processes, yielding tri-, tetra-, penta-, hepta-and nonagalloylglucose, and others (xiang et al., 2007; tian et al., 2009b) . pentagalloylglucose [1], 3-galloyl-gallic acid and 4-galloyl-gallic acid isomers isolated from galla chinensis are reported to be the primary bioactive gallotannins, possessing numerous medicinal activities and health benefi ts sakai et al., 1990; bhimani et al., 1993; feldman et al., 2001; . rhus chinensis is rich in well known phenolic compounds, gallic acid [2] and methyl gallate [3] (ahn et al., 1998 (ahn et al., , 2005 bae et al., 1998; choi et al., 2009 ). according to buziashvili et al. (1973) galla chinensis is composed of nearly 20% gallic acid and 7% methyl gallate. a new benzofuranone, 5-hydroxy-3-(propan-2-ylidene)-7-(3,7,11,15-tetramethylhexade-ca-2,6,10, 11-tetraenyl)-2(3h)-benzofuranone [4], together with 16 known bioactive compounds, including 5-hydroxy-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3h)-benzofuranone [5], 3-oxo-6β-hydroxyolean-12en-28-oic acid [6], 3-oxo-6β-hydroxyolean-18-en-28-oic acid [7] moronic acid [8], betulonic acid [9], gallicin [10], dihydroxytoluene [11] and dimethylcaffi c acid [12] , have been isolated from the root stem of rhus chinensis (gu et al., 2007; wang et al., 2008) . phenol glycosides and lariciresinol-based ligan glycosides compounds have been shown to be present in the butanol extract of rhus chinensis root (ouyang et al., 2007 (ouyang et al., , 2008 . 6-pentadecylsalicylic acid, an antithrombotic compound [13] (kuo, 1991) and fi setin (3,7,3-,4-tetrahydroxyfl avone) [14] an antiinfl ammatory, have also been isolated from the stem of rhus chinensis. the leaves of this plant are rich in essential oils, with palmitic acid, phytol and n-heptacosane as the major components (zhu et al., 2007) . the high level of gallotannins along with phenolic compounds, gallic acid and methyl gallate, known antimicrobial agents make galla chinensis very useful in bacterial control (wu-yuan et al., 1988; ahn et al., 1998; kang et al., 2008; tian et al., 2009a tian et al., , 2009b . extracts from galla chinensis inhibited several bacteria such as bacillus subtilis, b. cereus, escherichia coli, enterobacter cloacae, helicobacter pylori, klebsiella oxytoca, lactobacillus casei, l. acidophilus, l. salivarius, salmonella derby, s. minesota, s. typhimurium, s. enteritidis, shigella dysenteriae, staphylococcus aureus, streptococcus mutans, s. sobrinus, ureaplasma urealyticum, with the minimal inhibitory concentration (mic) in the range 0.5-8 mg/ ml (wu-yuan et al., 1988 , bae et al., 1998 choi ii et al., 2002; kang et al., 2008; zhu et al., 2008; choi et al., 2009; tian et al., 2009a) . tian et al. (2009b) reported that different gallotannins from galla chinensis separated according to the number of galloylglucose had signifi cant antibacterial activities on bacillus cereus and salmonella typhimurium. structure activity relationship studies indicated that antibacterial activity was positively correlated with the numbers of galloyl groups and generally, gallotannins with higher molecular weights had strong antibacterial activities (tian et al., 2009a (tian et al., , 2009b . a methanol extract of galla chinensis was shown to have signifi cant growth-inhibitory activity towards harmful intestinal bacteria (ahn et al., 1994 (ahn et al., , 1998 . activity-directed fractionation of the methanol extract of galla chinensis has led to the isolation of gallic acid and its derivative methyl gallate as the major components involved in the observed antimicrobial activity. it was also reported that methyl gallate and gallic acid from galla chinensis had inhibitory effects on periodontopathic bacteria (mic = 1 mg/ml) and signifi cantly reduced the in vitro biofi lm formation of s. mutans (methyl gallate, 1 mg/ml gallic acid, 4 mg/ml, p < 0.05) (kang et al., 2008) . anti-hiv activity. in a recent study, different fractions of rhus chinensis showed potent anti-hiv-1 activity (wang et al., 2006) . subsequent anti-hiv guided fractionation of rhus chinensis led to the isolation of 17 compounds with potent anti-hiv-1 activity (gu et al., 2007; wang et al., 2008) . among those compounds, a new class of benzofuranone-type compounds 5-hydroxy-3-(propan-2-ylidene)-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3h)-benzofuranone [4] and 5-hydroxy-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3h)-benzofuranone [5] were found signifi cantly to suppress hiv-1 replication (gu et al., 2007) . compound [4] possessed signifi cant anti-hiv-1 activity with a therapeutic index (ti) of 42.40, whereas compound [5] showed moderate anti-hiv-1 activity with a ti of 3.28 (gu et al., 2007) . furthermore, the action mechanisms of the two benzofuranonetype compounds were investigated by wang et al. (2008) . these authors found that both compounds [4] and [5] inhibited hiv-1 replication in chronically infected h9 cells and may target late-stages of the hiv-1 life cycle. betulonic acid [9] an analogue of betulinic acid, a well known anti-hiv-1 agent (kashiwada et al., 1996; soler et al., 1996) exhibited moderate anti-hiv-1 activity with a ti value of 5.27-8.94 μm (gu et al., 2007; wang et al., 2008) . 3-oxo-6β-hydroxyolean-12-en-28-oic acid [6], 3-oxo-6β-hydroxyolean-18-en-28-oic acid [7] and moronic acid [8] are oleanolic acid-related triterpenes previously reported to have potential anti-hiv-1 activity (pengsuparp et al., 1994; soler et al., 1996; kashiwada et al., 1998) . these compounds showed weak anti-hiv activity with ti values of 4.14, 4.74 and 8.22, respectively (gu et al., 2007; wang et al., 2008) . mengoni et al. (2002) described the anti-hiv and the mechanism of action for oleanolic acid, both of which suggested that oleanolic acid inhibits hiv-1 protease activity in vitro. gallicins [10], gallic acid derivate-type compounds, have been reported to inhibit hiv-1 integrase . the work of wang et al. (2008) confi rmed the result in cell lines with a therapeutic index of 5.11. dihydroxytoluene [11] had the same extent of anti-hiv-1 activity with a ti of 5.34. wang and coworkers also showed that dimethylcaffi c acid [12] , caffeic acid phenylethyl ester derivate, has potent anti-hiv-1 activity with a ti value of 19.07. these values are relatively low compared with the control azt (ti > 471883) but the resistance and the adverse side effects to available conventional anti-hiv drugs beg the need of identifi cation and development of additional small-molecule inhibitors that can be used in combination with currently available antiviral agents. in vivo studies performed in mice have shown that the hot-water extract of rhus chinensis had prophylactic and therapeutic efficacy against herpes simplex virus (hsv) type 1 (hsv-1) (kurokawa et al., 1993 (kurokawa et al., , 1995a (kurokawa et al., , 1995b (kurokawa et al., , 1997 . this extract was also effective against acyclovir-resistant hsv-1 and hsv type 2 (hsv-2) infections in mice (kurokawa et al., 1995b) and improved the therapeutic effi cacy of acyclovir in mice infected with hsv-1 (kurokawa et al., 1995a) . subsequently, nakano et al. (1998) also investigated the effi cacy of rhus chinensis extract in vivo, using a guinea-pig primarily infected intravaginally with hsv-2. prophylactic oral administration of rhus chinensis at the dose corresponding to human use signifi cantly reduced the incidence and severity of spontaneous skin lesions compared with latently infected guinea-pigs administered water. when recurrent hsv-2 infection was induced by ultraviolet irradiation 3 months after primary infection, prophylaxis with rhus chinensis was also signifi cantly effective in reducing the severity of ultraviolet-induced skin lesions. two terpene compounds, moronic acid [8] and betulonic acid [9], were separated from rhus chinensis and their subsequent anti-hsv activities were assessed in vitro and in vivo . the effective concentrations of moronic acid and betulonic acid for 50% plaque reduction for hsv-1 were consecutively, 3.9 and 2.6 μg/ml. the therapeutic index of moronic acid (10.3-16.3) was larger than that of betulonic acid o. djakpo and w. yao (6.2). oral administration of moronic acid thrice a day to mice infected cutaneously with hsv-1, signifi cantly retarded the development of skin lesions and/or prolonged the mean survival of infected mice without toxicity compared with the control. moronic acid exerted stronger anti-hsv-1 activity in the brain of hsv-1-infected mice than in the skin, similar to the hotwater extract of rhus chinensis (kurokawa et al., 1995a . anti-hcv and anti-sars-cov activities. screening a library of traditional medicines, duan et al. (2004) found that the etoac extract fraction from galla chinensis was effi cient in inhibiting the ns3 protease activity of hepatitis carcinoma virus (hcv). 1,2,6-tri-o-galloyl-βd-glucose, 1,2,3,6-tetra-o-galloyl-β-d-glucose and pentagalloylglucose [1] were identifi ed as the active compounds. tri-, tetra-and pentagalloylglucose inhibited hcv ns3 protease with ic 50 of 1.89, 0.75 and 1.60 μm, respectively (duan et al., 2004) . likewise, tetra-o-galloyl-β-d-glucose isolated from galla chinensis exhibited prominent inhibition against severe acute respiratory syndrome coronavirus (sars-cov) with a 50% effective concentration of 4.5 μm (yi et al., 2004) . liu et al. (2003) found that crude aqueous extract of galla chinensis has the ability to inhibit enamel demineralization in vitro. in another study, chu et al. (2007) evaluated the effects of compounds from galla chinensis on the remineralization of initial enamel carious lesions using an in vitro ph cycling model. the group demonstrated the potential of three different fractions of galla chinensis to affect net rehardening of artifi cial carious lesions under dynamic ph-cyclic conditions. furthermore, zou et al. (2008) , using the same protocol, demonstrated the potential of galla chinensis extract to inhibit the demineralization of initial enamel carious lesions. the chemical compounds of galla chinensis showed effects and combined effects with fl uoride on enhancing remineralization of dental enamel (cheng et al., 2008) . at this point, the active compound of galla chinensis involved in remineralization or demineralization is still unknown. chu et al. (2007) isolated gallic acid [2] and methyl gallate [3], both of which showed poor activity compared with the crude extract. this result was confi rmed by cheng et al. (2008) testing the combined effects of galla chinensis extract or gallic acid with fl uoride on remineralization of artifi cial early enamel caries. they found that both the crude extract of galla chinensis and gallic acid had synergistic effects with fl uoride on remineralization, but with apparent differing mechanisms. thus, it seemed that gallic acid was not the only possible active constituent of galla chinensis to enhance remineralization. zou et al. (2008) similarly attempted to determine which of the constituent chemical fractions of galla chinensis conferred a potential anticaries benefi t by comparing the effects of four different fractions of galla chinensis on demineralization of a bovine enamel model. the crude extract was the most active one, prone to some losses of other active compounds during the separation process. cai et al. (2004) screened 112 chinese medicinal plants for antioxidant activity; the results showed that the aqueous extract of galla chinensis contained the highest antioxidant concentration of 17674 μmol teac/100 g. more recently, two similar studies have investigated the antioxidant activity of gallotannins in four different systems, namely 1,1-diphenyl-2-picrylhydrazyl (dpph) radical scavenging, ferric reducing antioxidant power, β-carotene linoleic acid system and hydroxyl radical scavenging assays. tian et al. (2009a) tested the antioxidant activity of gallotannins with different polarities and found that all of the consecutive extracts of galla chinensis possessed remarkable antioxidant activity. for example, dpph radical scavenging activity, ec 50 were in the sequence ethyl acetate (1.22 μg/ml) > ether (1.44 μg/ml) > ethanol (1.55 μg/ml) > water (2.11 μg/ml). generally, all fractions showed better capacity to scavenge free radicals than the controls, bht and trolox. the same results trend was observed with ferric reducing activity. antioxidant activity increased when the polarity of extracts decreased, suggesting that extracts with weaker polarities contained higher molecular weight tannins, and thus had stronger antioxidant effects. aware of this fi nding, tian et al. (2009b) isolated different gallotannins, containing 1-10 galloylglucoses (gg), from galla chinensis and investigated their antioxidant activities in the above systems. generally, gallotannins of high degrees of galloylation (5-10 ggs) had stronger antioxidant activities than those of low degrees of galloylation (1-4 ggs).the same conclusion was drawn in earlier work by yokozawa et al. (1998) . similarly, methyl gallate and gallic acid have been shown through in vivo and in vitro studies to have antioxidant and radical scavenging activity (chen and zhang, 2003; whang et al., 2005; madsen and bertelsen, 1995; peyrat-maillard et al., 2000) . it has been demonstrated that pentagalloylglucose possesses antioxidant activity and protects rat neuronal cells from oxidative damage feldman et al., 2001; oh et al., 2001; pan et al., 1999) . piao et al. (2009) showed that pentagalloylglucose exerts antiapoptotic activity through antioxidant properties. yang et al. (2005) were the fi rst to report the anticancer activity of rhus chinensis extract on carcinogenic cdc25 phosphatases. several molecules found in rhus chinensis such as pentagalloylglucose and gallic acid have been shown to have anticancer activity (bhimani et al., 1993; madsen and bertelsen, 1995; chung et al., 1998; hu et al., 2008; kuo et al., 2009) . pentagalloylglucose has been shown to exhibit in vivo anticancer effects against prostate cancer (hu et al., 2008; kuo et al., 2009) , lung cancer (huh et al., 2005) and sarcoma (miyamoto et al., 1987) , and in vitro inhibitory effects on the growth and/ or invasion of breast cancer, leukemia, melanoma and liver cancer . pentagalloylglucose can exert anticancer activity via the inhibition of angiogenesis (lee et al., 2004; huh et al., 2005) and invasion of melanoma cells in metastasis (ho et al., 2002) . in vitro studies showed that pentagalloylglucose signifi cantly inhibited the proliferation and tube formation of bfgfphytother. res. 24: 1739-1747 (2010) treated human umbilical vein endothelial cells (huvec) with an ic 50 of 8 μm (huh et al., 2005) . the result is similar to the in vitro antiangiogenic activity of pentagalloylglucose in vegf-treated huvecs (lee et al., 2004) . daily injection of 4 and 20 mg/kg of pentagalloylglucose signifi cantly inhibited the growth of the highly angiogenesis-dependent lewis lung cancer allograft by 57% and 91%, respectively (huh et al., 2005) . similarly, pentagalloylglucose inhibited the invasion of highly metastatic mouse melanoma b16f10 cells in vitro in a dose-and time-dependent manner, with ic 50 of 15 μm (ho et al., 2002) . some other investigations have also demonstrated that derivatives of galloylglucose inhibit not only cancer cell growth (pan et al., 1999; hu et al., 2008) but also the invasion of ht1080 human fi brosarcoma cells (ata et al., 1996) . several studies of natural hepatoprotective agents have revealed that the extract of galla chinensis showed promising hepatoprotective activity tian et al., 2005) . based on an activity-guided separation scheme an et al. (2005) purifi ed pentagalloylglucose [1] and an equilibrium mixture of 3-galloyl-gallic acid and 4-galloyl-gallic acid isomer from the methanol extract of galla chinensis and validated their hepatoprotective activity. pentagalloylglucose [1] and the mixture compounds were found to have marked protective effects on tacrine-induced cytotoxicity in human liver-derived hep g2 cells with ec 50 values of 70.39 ± 5.4 and 29.51 ± 0.7 μm, respectively, and also inhibited nitrofurantoininduced cytotoxicity in hep g2 cells at 150.9 ± 6.4 and 23.81 ± 0.5 μm respectively. furthermore, pentagalloylglucose treatment was able to reduce both hepatocyte necrosis induced by tertbutyl hydroperoxide (4 and 20 μm) and apoptosis induced by glycochenodeoxycholic acid (3.125 to 50 μm) in primary rat hepatocytes (park et al., 2008) . diabetes mellitus is a chronic metabolic disorder characterized by high blood glucose level due to agents such as α-glucosidase enzyme, which boosts the digestion of carbohydrate to monosaccharides in the process of intestinal absorption. therefore, shim et al. (2003) tested the inhibitory effect of an aqueous extract from the gall of rhus chinensis on α-glucosidase activity in in vitro and in vivo models. galla chinensis inhibited bacillus α-glucosidase activity with an ic 50 of 0.9 μg/ml. its inhibition on α-glucosidase was determined to be noncompetitive and reversible when the enzyme-substrate mixture was simultaneously treated with galla chinensis. galla chinensis signifi cantly suppressed the increase of blood glucose level in rats after oral administration of sucrose. these results suggest that galla chinensis might exert antidiabetic effects by suppressing carbohydrate absorption from the intestine and thereby reducing the postprandial increase in the blood glucose. likewise, tannic acid, a mixture of gallotannins containing pentagalloylglucose, was found to have a hypo-glycemic effect in patients with type 2 diabetes (gin et al., 1999) . aware of this result, li and coworkers hypothesized that pentagalloylglucose could have antidiabetic activity. using synthetic pentagalloylglucose in vitro and in an animal assay, it was demonstrated that pentagalloylglucose effectively reduced blood glucose and insulin levels in vitro and in animal models (li et al., 2005) . unlike most antidiabetic drugs, pentagalloylglucose may reduce blood glucose without increasing adiposity. the methanol extract of the dried ripe fruit of rhus chinensis was tested in experimental models of castor oil-induced diarrhea in swiss albino mice (tangpu and yadav, 2004; bose et al., 2008) . at graded doses, the extract showed remarkable antidiarrheal activity evidenced by an 80.70% reduction in the rate of defecation of control animals at a dose of 600 mg/kg body weight. the extract also reduced intestinal fl uid secretion induced by mgso 4 and gastrointestinal motility after charcoal meal administration in albino mice (tangpu and yadav, 2004) . in the same way, galla chinensis extracts were found to be effective against enterotoxigenic escherichia coliinduced diarrhea that produces a heat-labile enterotoxin (lt), which binds to the ganglioside g m1 on the surface of intestinal epithelial cells (holmgren and svennerholm, 1992) leading to a massive loss of fl uids and ions from cells (chen et al., 2009) . using the patent mouse gut assay in vivo study, chen et al. (2006) found that galla chinensis extract exhibited an anti-lt-induced diarrheal effect, with an ic 50 value of 4.7 ± 1.3 mg/ml. competitive gm1-elisa assay showed that galla chinensis suppressed (ic 50 = 0.17 ± 0.02 mg/ml) ltinduced fl uid accumulation by blocking the binding of ltb to g m1 . thin layer chromatography suggests that the most active fraction that inhibited the binding of ltb to gm1 was composed of mainly phenolics, especially gallic acid which signifi cantly blocked the binding of ltb to g m1 , with an ic 50 value of 10.9 ± 0.3 mm, and suppressed the lt-induced fl uid accumulation in a dose-dependent manner, with an ic 50 value of 25.4 ± 11.6 mm. the work of kim et al. (2005) showed that galla chinensis had antiinfl ammatory activity in in vivo and in vitro models. galla chinensis could control all of the infl ammatory mediators, such as histamine, heparin, lipidderived mediators and various cytokines in the model of immediate-type allergic reaction in a dose-dependent manner through different mechanisms. latter activityguided fractionation and purifi cation of the etoac fractions of the galla chinensis indicated that the main antiallergic component in galla chinensis was gallic acid. fisetin a fl avonoid found in the root of rhus chinensis (lin et al., 2008) was also found to down-regulate infl ammatory reactions in stimulated human mast cells . similarly, pentagalloylglucose has been shown through in vivo and in vitro studies to exercise a strong antiinfl ammatory effect (oh et al., 2004; lee et al., 2007 lee et al., , 2003 kang et al., 2005) . 6-pentadecylsalicylic acid has been isolated from airdried stems of rhus chinensis by bioassay-directed fractionation of the n-hexane extract of the stem (kuo, 1991) . this compound showed antithrombotic activity at 50 μg/ml using the amidolytic method (kuo, 1991) . it also prolonged clotting time in a dose-dependent manner in the clotting assay of thrombin-fi brinogen interaction. rhus chinensis species have long been recognized by folk medicine practitioners as having value and have been revealed to have great medicinal potential, much of which was completely unknown to western scientists. over the past few decades, the research efforts on rhus chinensis extracts indicate that the extracts have promising potential as antiviral, anticarie, antidiarrheal, anticancer, antidiabetic and hepatoprotective agents, among others. although the work reviewed here substantiated most of the traditional claims on its health effectiveness, more research is required for validation of the uses of this plant. the available information on the different bioactive contents in samples of various parts of this medicinal plant is very limited, both qualitatively and quantitatively. the gall on rhus chinensis leaves has received much scientifi c attention because of its high gallotannin content and subsequent health potential. however, other parts, such as fruits, leaves, and seeds, can also be investigated based on traditional uses and the fi ndings in other rhus species. , 5-hydroxy-3-(propan-2-ylidene)-7-(3,7,11,15-tetramethylhexade-ca-2,6,10,11-tetraenyl)-2(3h)-benzofuranone [4], 5-hydroxy-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3h)-benzofuranone [5], 3-oxo-6β-hydroxyolean-12-en-28-oic acid [6], 3-oxo-6β-hydroxyolean-18-en-28-oic acid [ so far, galla chinensis is the only medicine proven to remineralize a hard tissue like enamel. this is a unique potential for this plant, but the active constituent is still unknown. the mechanistic activity of rhus chinensis material as prophylactic, therapeutic, anti-hsv, anti-hiv and antidiarrheal medicine needs to be further examined. on the other hand, efforts should also be made to survey other sumac species to determine if these properties are generalized across the rhus genus. the safety of rhus chinensis still needs to be rigorously established, since cases of toxicity from intake of gallotannins found in rhus chinensis have been reported in the literature. different gallotannins such as tri-, tetra-, hexa-, hepta-, octa-, nona-and decagalloylglucose can reduce blood pressure and blood urea nitrogen, as reported in animal studies in the literature (feldman et al., 1999; hofmann et al., 2006; nishizawa et al., 1983) . nonetheless, tannins diminish protein digestibility when present in high levels in diets with low protein content and also inhibit human salivary α-amylase, thereby causing potential negative effects on starch digestion and food taste. this needs to be taken in account when testing the effi cacy of rhus chinensis compounds in human beings by clinical trials for drug use validation. 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effects on urea-nitrogen concentration in rat serum penta-o-galloyl-β-dglucose inhibits phorbol myristate acetate-induced interleukin-8 [correction of intereukin-8] gene expression in human monocytic u937 cells through its inactivation of nuclear factor-kappab in vitro anti-proliferative effect of 1,2,3,4,6-penta-o-galloyl-β-d-glucose on human hepatocellular carcinoma cell line, sk-hep-1 cells sesquiterpenes with hepatoprotective activity from cnidium monnieri on tacrineinduced cytotoxicity in hep g2 cells four new lariciresinol-based lignan glycosides from the roots of rhus javanica var. roxburghiana new phenol glycosides from the roots of rhus javanica var. roxburghiana induction of apoptosis by penta-o-galloyl-beta-d-glucose through activation of caspase-3 in human leukemia hl-60 cells anti-infl ammatory activity of fi setin in human mast cells (hmc-1) ,6-penta-o-galloyl-β-d-glucose from galla rhois protects primary rat hepatocytes from necrosis and apoptosis phenolic constituents 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matrix-assisted laser desorption/ionization time of fl ight mass spectrum of chinese gallotannins chinese medicinal herb iconograph i chemistry of traditional chinese medicine. shanghai science and technology publishing house screening the active constituents of chinese medicinal herbs as potent inhibitors of cdc25 tyrosine phosphatase, an activator of the mitosisinducing p34cdc2 kinase handbook of chinese herbs and formulas. institute of chinese medicine small molecules blocking the entry of severe acute respiratory syndrome coronavirus into host cells study on the inhibitory effect of tannins and fl avonoids against the 1,1-diphenyl-2-picrylhydrazyl radical anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucose chemical variation in leaf essential oils of rhus chinensis from eight locations in southern and eastern china microdilution inhibition test of chinese herbs to assess their effect against clinical strains of ureaplasma urealyticum in vitro chinese materia medica effect of galla chinensis extract and chemical fractions on demineralization of bovine enamel in vitro the authors have declared that there is no confl ict of interest. key: cord-294897-29diwyoe authors: pina-pérez, m. c.; rivas, a.; martínez, a.; rodrigo, d. title: antimicrobial potential of macro and microalgae against pathogenic and spoilage microorganisms in food date: 2017-11-15 journal: food chemistry doi: 10.1016/j.foodchem.2017.05.033 sha: doc_id: 294897 cord_uid: 29diwyoe abstract algae are a valuable and never-failing source of bioactive compounds. the increasing efforts to use ingredients that are as natural as possible in the formulation of innovative products has given rise to the introduction of macro and microalgae in food industry. to date, scarce information has been published about algae ingredients as antimicrobials in food. the antimicrobial potential of algae is highly dependent on: (i) type, brown algae being the most effective against foodborne bacteria; (ii) the solvent used in the extraction of bioactive compounds, ethanolic and methanolic extracts being highly effective against gram-positive and gram-negative bacteria; and (iii) the concentration of the extract. the present paper reviews the main antimicrobial potential of algal species and their bioactive compounds in reference and real food matrices. the validation of the algae antimicrobial potential in real food matrices is still a research niche, being meat and bakery products the most studied substrates. and germany as pioneers in research and investment in this area (guedes, barbosa, amaro, pereira, & malcata, 2011) . furthermore, the study of natural bioactive compounds obtained from marine organisms is a relatively new field of research (since the '90s), with enormous scientific potential (cakmak, kaya, & asan-ozusaglam, 2014; mehadi et al., 2015) . given that oceans cover three quarters of the earth's surface, these marine organisms are of potential interest not only as ingredients for the production of food but also as practical and necessary metabolites with medical and technological properties, such as lipids, enzymes, biomass, polymers, toxins, pigments, and clean fuel, which can be produced, concentrated, and successfully isolated from these small but efficient ''marine bioreactors". these organisms are a viable and economical source for the production of these substances, and are in great demand in the nutraceutical, pharmaceutical, chemical, food, and cosmetic industries because of their moisturizing, antioxidant, and regenerative properties (batista, gouveia, bandarra, franco, & raymundo, 2013; devi, suganthy, kesika, & pandian, 2008; rani, singh, & maheshwari, 2013) . the possibility of an efficient and sustainable use of marine resources offers an important way of providing staple food, animal feed, pharmacological products, functional ingredients, and medical solutions for a global population that is rapidly increasing. the term ''algae" comprises a complex and heterogeneous group of photosynthetic organisms characterized by their photosynthetic nature and their simple reproductive structures. the algae group is divided into multicellular organisms, macroalgae or seaweed, and unicellular organisms, known as microalgae (measuring from 1 mm to several cm). macroalgae are often fastgrowing, reaching sizes of up to 60 m in length. a standard classification has been established, dividing seaweed organisms into three groups on the basis of their pigmentation: i) brown seaweed (phaeophyceae); ii) red seaweed (rhodophyceae) and iii) green seaweed (chlorophyceae). seaweeds are mainly used for the production of food and the extraction of hydrocolloids. on the other hand, microalgae are microscopic bodies that normally grow in suspension, some with features characteristic of bacteria. these algae grow in seawater, in the region where light penetrates (photic zone), basically up to a depth of 200 meters. diatoms (bacillariophyceae), green algae (chlorophyceae), and golden algae (chrysophyceae) are the most important microalgae in terms of abundance, but blue-green algae (cyanophyceae) are also classified as microalgae (e.g. spirulina) . more than ten million algal species are estimated to exist nowadays, most of them microalgae, representing a virtually unexplored plant material. so far, only about 50 species have been studied in detail from a physiological and biochemical point of view, in the discipline of ''phycology". the remarkable biodiversity of algae, ranging from species found in the coldest regions of antarctica to those that grow in the hottest deserts, opens up a new research niche, mainly in the baseline of the ''functionality of these marine vegetables". among the various research fields in which macro-and microalgae are appearing, gastronomy and food technology are two of the most important areas. new trends in cooking are emphasizing the use of algae as healthy, tasty, colorful ingredients to accompany the most innovative dishes. france, ireland, canada, and the united states are particularly active in introducing seaweed into local cuisine, and the movement is spreading to cookery books that include recipes with algae as the main ingredient (fao, 2012) . consumers have a good perception of algae as ''natural products", like lettuce, chard, or broccoli, with well-known, accepted health benefits (honkanen, 2009) . humans have certainly been consuming algae for years: pet foods, baby foods, dairy products, instant soups, meat coatings (cooked ham), and many others commodities are clear examples of the presence of seaweed in our daily diet. nowadays, most of these algae ingredients correspond to eu labeled additives no 1333/2008). exciting organoleptic properties (color, flavor, aroma, and taste) are being developed by introducing algae into the formulation of novel products with additional technological functions, including preservative functions (antibacterial, antifungal, antiviral, bacteriostatic) (el shoubaky & el rahman-salem, 2014; sanmukh et al., 2014; tüney, çadirci, ünal, & sukatar, 2006) , structural functions (emulsifying, gelling, and thickening properties attributed to algae) (ursu et al., 2014) , and nutritional properties (vitamins, proteins, polyunsaturated fatty acids) (bishop & zubeck, 2012; el-baky, el baz, & el-baroty, 2008) . spirulina maxima, chlorella vulgaris, haematococcus pluvialis, diacronema vlkianum, and isochrysis galbana are some of the most interesting algae with potential bioactive properties (batista et al., 2013) . all of them are able to accumulate high amounts of bioactive compounds with functional and technological properties. several products, such as pasta, bread, and snacks, are being developed with the incorporation of algae extracts in their formulation, and expectations about this practice are promising for the food industry. in view of the development of antibiotic resistance in bacteria and international trade pressure to achieve a high level of consumer protection, new alternatives to traditional preservatives should be developed and introduced by the food industry, even in products with limited shelf life. the new line of preservatives should also accomplish two further objectives, (i) to preserve the quality and organoleptic value of the product, and (ii) to satisfy consumer demand for natural, functional, ready-to-eat meals. in this connection, marine algae are emerging as a new generation of potential preservatives, macro-and microalgae extracts, or pure ingredients with health benefits and demonstrated antibacterial, antifungal, and antiviral activities (dai & mumper, 2010; devi et al., 2008) . although intensive study of the antimicrobial potential of algae has begun [2005] [2006] [2007] [2008] [2009] [2010] [2011] [2012] [2013] [2014] [2015] [2016] , most of the studies that have been published are about therapeutic and antibacterial/antiviral capabilities of algae compounds, their ability to inhibit or kill clinical bacteria (mehadi et al., 2015; rajeshkumar et al., 2014; rhimou, hassane, josé, & nathalie, 2010) , but not about the effect of these bioactive molecules against foodborne pathogens and spoilage microorganisms commonly found in food matrices. among the major bioactive constituents of algae with demonstrated antimicrobial potential, proteins, polysaccharides, polyunsaturated fatty acids (pufas), especially epa and dha, amino acids, and antioxidants (polyphenols, flavonoids, and carotenoids) are the most important ones (al-saif, abdel-raouf, el-wazanani, & ibrahim, 2014; senthilkumar & sudha, 2012) . however, the identification of compounds directly responsible for the antimicrobial potential of algae is still a relatively incipient field of research, mainly owing to the new kinds of compounds found in recent years . the recent year 2014 was designated as ''protein year", underlining the importance of finding alternative sources of these valuable molecules, proteins of animal and vegetable origin. in this field, algae take a high position among the raw materials proposed as alternative protein sources, together with soy, beans, grains, and, recently, insects . algae protein quality has been considered superior to that of other plant sources, such as wheat, rice, or beans, but poorer than that of animal protein sources, such as milk or meat (mendes, lopes da silva, & reis, 2007) . however, interest in marine proteins might be directly correlated not only with intact protein but also with the possibility of generating bioactive peptides. small peptides are generally considered to be the most ancient antimicrobial agents because of their ubiquity and simple molecular structure. in general, bioactive peptides comprise relatively small molecules (<10 kda, or 12-50 amino acids) that do not present any bioactivity prior to being released from the intact parent protein. however, in various processes such as digestion or in vivo hydrolysis, or as a result of application of technological treatments such as high pressure processing, these peptides demonstrate many physiological functions, including antioxidant, antihypertensive or ace inhibition, anticoagulant, and antimicrobial properties (ngo, wijesekara, vo, ta, & kim, 2011) . antimicrobial peptides are recognized as being divided into three groups: (i) linear a-helical peptides; (ii) cysteine-rich peptides; (iii) certain amino-acid-enriched peptides. critical factors affecting the antibacterial activity and modes of action of antimicrobial peptides are size, charge, conformation/secondary structure, hydrophobicity, and origin (animal/plant or marine) (aneiros & garateix, 2004) . according to the studies of al-saif et al. (2014) , the higher antimicrobial potential of several algae strains against escherichia coli (atcc 25322), pseudomonas aeruginosa (atcc 27853), staphylococcus aureus (atcc 29213), and enterococcus faecalis (atcc 29212) was directly related to the greater protein content detected in them. according to those studies, the most effective marine alga against the bacteria that were tested was g. dendroides, with a protein content of 13.4%, followed by u. reticulata (5.8%), cladophora socialis (2.3%), and c. occidentalis (1.7%). lectins are a class of carbohydrate-recognizing proteins that bind to cells, promoting hemagglutination and an antimicrobial effect. smith, desbois, and dyrynda (2010) reported the antimicrobial potential of lectins obtained from algae, with two red algal species, eucheuma serra and galaxaura marginata, being responsible for an inhibiting potential against vibrio vulnificus and v. pelagicus. the antimicrobial activity of lectins obtained from red algae against some clinical microorganisms was also observed by alves-vasconcelos et al. (2014) . although the way in which lectins act against bacteria is not well defined, paiva et al. (2010) reported that the antibacterial activity of these compounds against grampositive and gram-negative microorganisms is related to the interactions that occur between lectins and other bacterial cell wall components, including teichoic acids, peptidoglycans, and lipopolysaccharides (table 1) . macroalgae are rich sources of dietary fiber (25-75%), of which water-soluble fiber constitutes approximately 50-85% (wet basis). polysaccharides are some of the most important constituents of seaweed (kraan, 2012) . phaeophyta, or brown algae, are specifically rich in polysaccharides, including alginates, laminarins, fucans, and cellulose. chlorophyta, or green algae, are mainly composed of ulvan. the principal polysaccharides found in rhodophyta, or red algae, are agars and carrageenans. these polysaccharides obtained from algae have been related to positive effects on gut microbiota, acting as prebiotics, a prebiotic being a ''selectively fermented ingredient that allows specific changes, both in the composition and/or in the activity of the gastrointestinal microflora, that confers benefits upon host well-being and health". reduction of enteric infections in pigs and cattle is possible by means of administration of prebiotic compounds in the diet which promote the activity and proliferation of beneficial gastrointestinal microflora to the detriment of pathogenic bacteria (uyeno, shigemori, & shimosato, 2015) . the use of marine algal prebiotics as sources to control and reduce pathogenic bacteria and to improve animal and human health is another possibility that this line of research offers (promya & chitmanat, 2011) . the polysaccharide ulvan is easily extracted from ulva rigida, and could be hydrolyzed to produce bioactive oligosaccharides (mišurcová, škrovánková, samek, ambrožová, & machů , 2012) . also, oligosaccharides from brown algae have demonstrated antimicrobial potential in vivo inhibiting salmonella enteritidis colonization in broiler chickens (asthon acton, 2012) . another very interesting group of polysaccharides obtained from algae with a demonstrated antimicrobial potential is fucoidans (polysaccharides from phaeophyta). among the most important properties of these polysaccharides are the following: anticoagulant, antithrombotic, antiviral, antitumor, immunomodulatory, antioxidant, and anti-inflammatory (li, lu, wei, & zhao, 2008; marudhupandi & kumar, 2013) . according to the studies of de jesus raposo, bernardo de morais, and santos costa de morais (2015), sulphated polysaccharides from seaweeds (among them alginates, fucoidans and laminaran) have demonstrated to be effective against e. coli and staphylococcus aureus (chaetomorpha aerea, 50 mg/ml of extract). moreover, also carrageenans and the sulphated exopolysaccharide (seps) from the red microalga porphyridium cruentum are specifically effective inhibiting one of the most relevant foodborne pathogens, salmonella enteritidis (pierre et al., 2011) . recent studies have also demonstrated the potential of fucoidans for preventing helicobacter pylori infection, one of the most concerning emergent foodborne pathogens affecting 50-80% of the worldwide population. the effect of fucoidan from brown algae as a potential antimicrobial against h. pylori thereby reduces the risk of associated gastric cancers (marudhupandi, kumar, senthil, & devi 2014) . laminaria spp. extract containing either laminarin or fucoidan, or a combination of both, resulted in a reduction of fecal e. coli populations in piglets fed with 0.3 and 0.24 g/kg, respectively (o'doherty, mcdonnell, & figat, 2010) , consequently reducing the initial bacterial load in derived raw meat products (table 2) . these studies point out the potential of prebiotics from algae origin not only as potential antimicrobial ingredients in food, but also such as antimicrobial agents in vivo to be regularly added to diet and inhibiting the pathogenic bacterial proliferation in intestine (e.g. in both animal and human fed). one of the most valuable nutritional properties of algae is related to their high content of polyphenols, carotenoids, and flavonoids, referred to as antioxidants. antioxidants act to protect the human body against damage by reactive oxygen species (ros), which can lead to health disorders such as cancer, diabetes mellitus, neurodegenerative diseases, and inflammatory diseases with severe tissue injuries (rani et al., 2013) . among the different metabolites in algae, antioxidants are the most extensively studied (manivannan, karthikai, anantharaman, & balasubramanian, 2011; senthilkumar & sudha, 2012) . antioxidants are very powerful tools with which to fight oxidative stress and thus improve the health status of the general population (rani et al., 2013) . phenols constitute the largest group of secondary metabolites identified in algal species. in recent studies, a broad spectrum of in vitro antibacterial activity has been associated not only with plant phenols but also with phenols from algae, specifically against staphylococcus aureus and bacillus spp. other antimicrobial phenolic compounds isolated from the marine environment include anthraquinones, coumarins, and flavonoids . rutin, quercetin, and kaempferol flavonoids have been identified in all the algal species with antimicrobial potential, being present in different ratios in different species. according to the studies of al-saif et al. (2014) , the alga g. dendroides showed the highest concentration of these three flavonoids (rutin, 10.5 mg/kg; quercetin 7.5 mg/kg; kaempferol 15.2 mg/kg), and was also the most effective of the flavonoids studied in inhibiting bacterial growth (e. coli, p. aeruginosa, s. aureus, e. faecalis). the first antibacterial compound isolated from a microalga, chlorella spp., was a mixture of fatty acids. this compound was effective against both gram-positive and gram-negative bacteria (vello et al., 2014) . membrane-derived fas from macro-and microalga species have been associated with microbicidal activity as a mechanism of defense against viruses, protozoans, and bacteria (leflaive & ten-hage, 2009 ). the characteristic saturated and unsaturated fatty acids profile in algae, with a predominance of myristic, palmitic, oleic, and eicosapentaenoic acids (epa), is a specific feature associated with the antimicrobial potential of algal species (el shoubaky & el rahman-salem, 2014) . furthermore, palmitic acid has been assumed to be primarily responsible for the antibacterial activity of algae (al-saif et al., 2014; bazes et al., 2009 ). according to al-saif et al. (2014) .2]%, respectively, were associated with the highest antimicrobial potential, and the alga with the highest percentage of palmitic acid (75.5%), g. dendroides, was the most effective one against the bacteria studied. according to guedes et al. (2011) , the mechanism of action of fatty acids as antimicrobials may be due to cell leakage derived from membrane damage. some efforts are now being focused on identifying the compounds directly responsible for the antimicrobial capability of macro-and microalgae, taking into account that this is a relatively unexplored field of study (sanmukh et al., 2014) . in general, it could be said that the most antimicrobial compounds in algae are mainly polyphenols and polysaccharides that act by inhibiting microbial growth, or directly by destroying the living structures of microorganisms (bajpai, 2016) . novel extraction technologies (araujo et al., 2013; esquivel-hernández et al., 2016) and chemical extraction procedures (adam, abert-vian, peltier, & chemat, 2012; hammed et al., 2013) , are both applied to obtain selective extracts of algae rich in desired functional/antimicrobial compounds (dai & mumper, 2010) . since the late '70 s, various processes for obtaining extracts from seaweed have been developed, based on solid-liquid extraction, mainly by combining organic solvents, for example, [chloroform: methanol] mixtures, or acetone. additionally, some operations such as ultrafiltration processes are added to enhance selectivity. other methods use ethanol in a first step to precipitate protein, followed by a second stage extraction with hexane, butanol, or ethyl acetate. recent studies show that it is possible to use ternary mixtures of solvents (ethanol-hexane-water [77:17:6]) to form a homogeneous solution, with the advantage of significantly increasing the extraction yield and purity of the compounds extracted by a single stage, based on the high solubility of the compounds in the extractant mixture (parniakov et al., 2015) . the antimicrobial potential of algae extracts is dependent on the capability of the solvent to extract certain bioactive compounds, and also dependent on the sensitiveness of bacteria or fungi to these selective extracted compounds (al-saif et al., 2014; cakmak et al., 2014) . in general, these traditional extraction techniques, such as soxhlet, solid-liquid extraction (sle), or liquid-liquid extraction (lle), are time-consuming procedures that use high volumes of solvents and obtain low extraction yields. growing concern about the use of clean technologies to extract bioactive compounds from algae has led the international scientific community and r & d engineers to invest in technologies such as supercritical fluid extraction, extraction using high intensity pulsed electric fields (pefs), t ultrasonically assisted extraction (use) (parniakov et al., 2015) , microwave-assisted extraction (mae), and accelerated solvent extraction (ase), using pressure and temperature (esquivel-hernández et al. 2016 ) to preserve as much as possible of the quality and bioactivity of the extracted compounds . degradation of cell walls by an enzymatic pathway has also been used in microalgal treatment (e.g. in chlorella vulgaris), but it is still too expensive to be applied widely in industry (hammed et al., 2013) . the process of supercritical fluid extraction using co 2 is one of the most advanced techniques for obtaining bioactive compounds from algae. it is a highly efficient and fast way of obtaining extracts with high purity and rich in the desired functional compounds, but it remains relatively expensive as an industrial-scale method (mendiola et al., 2007) ultrasonically assisted extraction (use) is based on mechanical acoustic cavitation effects exerted on algae cell walls. among its main advantages are the effectiveness of the extraction process at room temperature, and therefore minimal loss of bioactive compounds. in microalgae, the use of ultrasound is already beginning to be widely used, with good results (adam et al., 2012; araujo et al., 2013) . the use of high intensity electrical pulses (pefs) is a method in which the application of high voltage pulses disrupts cellular material, facilitating the release of components such as proteins, chlorophylls, and carotenoids, among others. it has been successfully applied in bioactive extracts from spirulina and chlorella species. the method is based on the theory of electroporation, as the conductivity and permeability changes that occur in the cell membrane favor the formation of small pores that allow release of intracellular components to the environment (parniakov et al., 2015) . various dunaliella genus microalgal species have been treated by mae to favor extraction of carotenoids. microwave-assisted extraction promotes extraction by ohmic heating and homogeneous temperature distribution. the use of this technology in dunaliella tertiolecta and cylindrotheca closterium species has resulted in a process that combined rapid extraction, reproducibility, and a high yield (pasquet et al., 2011) , and other antimicrobial compounds (kadam, tiwari, & o'donnell, 2013) . until now, the antimicrobial potential of algae has generally been tested in vitro, using the agar diffusion method (cakmak et al., 2014; manivannan et al., 2011; qiao, 2010) . the broth dilution method (gupta, rajauria, & abu-ghannam, 2010) has also been used, providing a robust quantitative estimation of minimum inhibitory concentration (mic) values in a large number of samples. in the context of the present state of the art, in response to the food industry's demand for novel and alternative ingredients with high technological potential, the possibility of using seaweed and microalgae as natural preservatives to be added in the formulation of ''clean labeled foods" will soon become a reality. nowadays, the antimicrobial potential of algae against the main foodborne pathogens and spoilage microorganisms is one of the most interesting fields of research regarding the use of marine vegetables as sources of staple food and bioactives for human nutrition. the scientific advances and research focusing on this field that have been published to date are detailed below in order to provide the scientific community with a useful overview to help to guide future research trends/needs of research and the establishment of innovative projects. according to najdenski et al. (2013) , scenedesmus obliquus, chlorella sp., and nostoc sp. ethanolic extracts showed antibacterial potential against s. aureus. similarly, according to the studies of danyal, mubeen, and malik (2013) , ethanolic extract of pithophora oedogonium was effective in inhibiting the s. aureus growth. methanol and acetone extracts of scenedesmus spp. also exhibited antibacterial activity against s. aureus according to guedes et al. (2011) . furthermore, ishaq, matias-peralta, and basri (2016) found significant inhibitory activity of scenedesmus spp. acetone extract (0.35 mg/ml-3.48 mg/ml) against staphylococcus aureus (atcc 25923). methanolic extracts from nostoc spp., microcystis spp., scenedesmus spp., oscillatoria geminata, and chlorella vulgaris exerted a high antimicrobial potential against s. aureus and b. subtilis, with inhibition zone diameters between 16 and 18 mm (salem, hoballah, ghazi, & hanna, 2014) . these results are in agreement with those obtained by prakash, marimuthu, and jeeva (2011) regarding the antimicrobial potential of oscillatoria sancta and lyngbya birgei against this foodborne pathogen. manivannan et al. (2011) tested the brown seaweeds turbinaria conoides and padina gymnospora for their antimicrobial potential against s. aureus. s. aureus proved to be more resistant to t. conoides extracts (3-15 mm inhibition zone), but was more sensitive to p. gymnospora (10-16 mm inhibition zone). methanol and ethyl acetate extracts of t. conoides were the two most inhibitory ones against s. aureus. however, when growing s. aureus cells were exposed to p. gymnospora, diethyl ether and acetone were the extracts that inhibited cellular proliferation most effectively. methanolic and ethanolic extracts of dunaliella salina showed the lowest mbc against s. aureus (1.25 mg/ml) compared with other solvent extracts, such as hexane (mbc = 10 mg/ml) (cakmak et al., 2014) . the greatest antimicrobial potential of algae extracts against s. aureus was reported by tüney et al. (2006) , who observed an inhibitory diameter zone > 50 mm due to exposure of s. aureus to diethyl ether extract (0.5 g/ml) of fresh enteromorpha linza (0.5 g/ml), and a 38 mm inhibition zone in the case of fresh ulva rigida. this antimicrobial capabiity was not detected when the same fresh alga material was extracted with ethanol solvent. this led the researchers to the conclusion that some active compounds responsible for the antimicrobial potential against s. aureus are effectively extracted in diethyl ether, which produces larger halo zones than methanol, acetone, and ethanol, in which antimicrobial compounds are not completely dissolved and extracted. among the most effective antimicrobial compounds found in these algal species are terpenes, (e.g. usneoidone e, zosterdiol a, zosterdiol b, zosteronol, and zosteronediol) responsible for the antimicrobial and antiviral activity attributed to them (plaza del moral & rodríguez-meizoso, 2013). the antimicrobial potential of algae extracts is frequently compared with the potential of other currently used preservatives (at food industry level) or antibiotics (at clinical level). for example, devi et al. (2008) observed the effectiveness of haligra spp. seaweed extract (50 mg/ml) against s. aureus (mtcc 96), and found that the inhibitory potential of this alga extract was higher than the antimicrobial capability of sodium benzoate applied at a higher concentration (200 mg/ml). to date, most of the antimicrobial in vitro studies regarding the potential of algae against s. aureus have not been validated in food matrices. however, the promising results obtained against s. aureus were validated by the devi et al. (2008) research group by including haligra spp. extract at low concentrations in skimmed milk, demonstrating the effectiveness of 5 mg/ml as the minimum inhibitory concentration (mic) against s. aureus growth in dairy products. ascophyllum nodosum (brown phaeophyceae alga, in the fucaceae family) has been described by several authors as being effective in reducing the prevalence of e. coli o157:h7 in cattle before harvest (wang, xu, bach, & mcallister, 2009 ). moreover, according to the studies of wang et al. (2009) , antimicrobial activity from a. nodosum phlorotannins (pts) against various rumen microbes was observed, and it affected ruminal fermentation. in 2009 they published a new research work in which the bacteriostatic and bactericidal effects of pts from a. nodosum were evaluated against e. coli o157:h7, and were then compared with the antimicrobial potential of other tannins from terrestrial plant sources. an mic of 25 mg/ml was required to inhibit growth of e. coli o157:h7 strains (edl933 and e318 n) for 24 h at 37°c. pt bacteriostatic concentrations of 25 lg/ml or higher, and a bactericidal concentration ! 50 lg/ml, were required against the e. coli o157:h7 strains studied. according to ngo et al. (2011) , the potential biological activities of pts can protect the quality of food products against oxidative degradation by means of their antioxidant properties, and they can improve the safety of non-sterilized products as a control measure against microbial proliferation in the food chain. the antimicrobial potential exerted by pts from a. nodosum was explained by wang et al. (2009) . the technique of transmission electron microscopy was used to reveal the mechanism of action of pts against e. coli cells. the results of wang et al. (2009) indicated that tannins acted primarily on the bacterial cell wall. it seems that the patterns of structural disorganization by means of pt intervention were higher than the pattern observed as a result of the effect of terrestrial tannins e. coli o157:h7 cells. the antimicrobial potential of chaetomorpha linum, a green seaweed from the southeast coast of india, was tested against escherichia coli (mtcc no. 443), salmonella typhimurium (mtcc no. 98), and bacillus cereus (mtcc no. 430). methanolic extracts (90% w/v) of algae were tested by means of the agar diffusion method, assessing not only their antimicrobial capability but also their antioxidant potential, using the 1, 1-diphenyl-2-picrylhydrazyl radical (dpph) method. bacterial suspensions containing 1.5 â 10 8 cfu/ ml were inoculated in mueller-hinton agar plates. algal extracts were prepared at concentrations of 100, 300, and 500 mg/ml. the petri dishes were incubated for 16 h at 37°c and the inhibition zone was examined. a high correlation was found between the dpph antioxidant potential of methanolic c. linum extracts and the microbial inhibition capability exerted. the highest phenolic content of c. linum extract was 672.3 mg/gae/100 g/extract. e. coli was the most resistant bacterial strain to the effect of c. linum methanolic extract (senthilkumar & sudha, 2012) . the antimicrobial potential of t. conoides and p. gymnospora (kutz) vicker was tested by manivannan et al. (2011) against several microorganisms, including e. coli. the extraction procedure was carried out successively during a period of 10 h, using the following solvents: methanol, acetone, petroleum ether, ethanol, ethyl acetate, chloroform, and diethyl ether. the study conducted by manivannan et al. (2011) revealed that p. gymnospora extracts were significantly more effective against e. coli (8-17 mm inhibition zone diameter) than t. conoides extracts (2-8 mm inhibition zone diameter). when the bacterial growth was exposed to p. gymnospora extracts, the diethyl ether extract showed the greatest potential for inhibiting bacterial growth in agar plates, with a 17 mm inhibition zone diameter. the antimicrobial effectiveness of methanol, acetone, diethyl ether, and ethanol extracts from eleven seaweed species, fresh extract and dried extract, against growth of e. coli was assessed by tüney et al. (2006) . the results revealed that diethyl ether extracts of fresh c. mediterranea, e. linza, u. rigida, g. gracilis, and e. siliculosus (0.5 g/ml) showed effective results against gram-positive and gram-negative bacteria. the best inhibition results obtained with fresh and dried diethyl ether seaweed extracts were assayed against various pathogenic microorganisms. u. rigida and e. linza diethyl ether extracts showed the highest inhibition potential against e. coli (22 mm inhibition zone diameter), being c. mediterranea and g. gracilis also effective, with inhibition zone values between 16 and 20 mm. all of the most effective inhibition results were obtained with fresh materials. with regard to microalgae, the antimicrobial potential of d. salina against e. coli has also been tested. among the extracts studied, methanol and ethanol extracts of d. salina showed the highest effectiveness, achieving the lowest mbc against e. coli, 2.50 mg/ ml, compared with other solvent extracts such as hexane, which had an mbc of 10 mg/ml (cakmak et al., 2014) . according to manivannan et al. (2011) , salmonella typhimurium was slightly affected by t. conoides extracts, and was particularly sensitive to diethyl ether and petroleum ether extracts, with inhibition zone diameters in the range [8] [9] [10] [11] mm. these results are in agreement with those obtained by thirumaran and anantharaman (2006) regarding the antimicrobial potential of dictyota dichotoma against salmonella spp., concerning which they remarked that diethyl ether extracts showed the greatest inhibitory potential against salmonella paratyphi. on the other hand, p. gymnospora extracts showed higher antimicrobial potential against s. typhimurium, with inhibition zones of [7-24] mm. among the p. gymnospora extracts, chloroform and methanol were the most effective ones against this foodborne pathogen. t. conoides ethyl acetate extract showed the lowest inhibitory potential against salmonella spp. (%3 mm inhibition zone). the same inhibitory potential was detected for t. conoides acetone extract against salmonella spp. (%2 mm inhibition zone). the ethanolic extract of pithophora oedogonium was particularly effective against salmonella spp. (sanmukh et al., 2014) . similarly, ethanol extract of d. salina showed the lowest mbc against s. enteritidis (1.25 mg/ml), followed by methanolic extract with an mbc of 2.50 mg/ml. hexane extract was the least effective against s. enteritidis, with a required mbc of 10 mg/ml (cakmak et al., 2014) . high inhibition potential against s. typhimurium was exerted by chaetomorpha linum methanolic extract with concentrations in the range [100-500] lg/ml, producing inhibition zone diameters in the range [15-17] mm (senthilkumar & sudha, 2012) . ethanol extracts of p. oedogonium and botrydiopsis arhiz algal species were tested to assess their antimicrobial capability against two salmonella species isolated food samples, egg and meat, and named salmonella 1 and salmonella 4, respectively. the results revealed that p. oedogonium ethanolic extract was effective in inhibiting salmonella 1 growth, with an mic of 4 mg/ml (danyal et al., 2013) . according to the studies of el-baky et al. (2008) , several extracts of spirulina maxima were obtained from cells grown under different nitrogen levels [0.625-2.5 g/l nano 3 ), and their antimicrobial potential was assayed against various strains of bacteria. the s. maxima extracts were effective against b. cereus, with an antibacterial activity that was dose-dependent. mics in the range lg/ml were obtained, depending on the s. maxima extract applied. s. maxima extracts from cells grown at higher n levels were the most potent against all bacteria, with mic values of 30 lg/ml. the antibacterial activity of s. maxima was attributed by el-baky et al. (2008) to the presence of certain active components in all organic extracts, such as lipophilic and phenol compounds. according to the studies of cakmak et al. (2014) , different extracts (ethanol, hexane, dichloromethane, and methanol) of the microalga d. salina teodoresco (dunaliellaceae) were tested against various microorganisms, including bacillus cereus rskk 863. a minimum bactericidal concentration of 0.65 mg/ml of ethanol extract was required against b. cereus, corresponding to 2.50 mg/ml of d. salina fatty acids (palmitic (c16:0) > linolenic (c18:3 x3) > oleic (c18:1 x9) ). the studies of jang and lee (2015) revealed the high antimicrobial potential of two korean domestic algae, laurencia okamurae yamada and dictyopteris undulata holmes, against foodborne pathogens. b. cereus, s. aureus, and l. monocytogenes were particularly sensitive to laurencia okamurae yamada and dictyopteris undulata holmes extracts, and the antibacterial potential of both algae extracts was higher than that of streptomycin. dictyopteris undulata holmes was slightly more effective against b. cereus than laurencia okamurae yamada, with inhibition zones of 5.0 ± 0.2 mm and 4.0 ± 0.2 mm, respectively. the most effective inhibition potential against b. cereus has been reported by senthilkumar and sudha (2012) . c. linum methanolic 500 lg/ml extract resulted in a 27 mm inhibition zone against this foodborne pathogen. the total phenolic content (tpc) of the methanolic c. linum extract was determined by means of the folin-ciocalteu method, yielding a tpc value equal to 672.3 mg gae/100 g extract, related to significant antioxidant activity (as ascorbic acid equivalents). the higher scavenging activity of c. linum may be attributed to the structure of phenolic compounds, specifically to hydroxyl groups. accordingly, it could be said that the antimicrobial potential exerted by this methanolic c. linum extract is closely related to its antioxidant activity as measured by the dpph method, with the antioxidant potential of the extract being dose-dependent, with an ic 50 value of 9.8 lg/ml. the antimicrobial potential of ecklonia cava (laminariaceae family) was tested by nshimiyumukiza et al. (2015) against listeria monocytogenes. although the biological activities of e. cava (including antioxidant, antimicrobial, and immunomodulatory properties) have been previously reported, the study conducted by nshimiyumukiza et al. (2015) is the first to reveal the potential that this algae specie has against this relevant foodborne pathogen. several solvents were assayed in the process of extraction (methanolic extract, dichloromethane fraction, ethyl acetate fraction, butanol extract, and water fraction) of bioactive antimicrobial compounds. the methanolic extract of ecklonia cava exhibited the highest antibacterial activity against l. monocytogenes kctc 3710, with the ethyl acetate (etoac) soluble fraction having an mic value of 256 lg/ml and an mbc value of 512 lg/ml. methanolic and ethanolic extracts of the microalga d. salina teodoresco (dunaliellaceae) were particularly effective against listeria monocytogenes atcc 7644, with a mbc of 2.5 mg/ml compared with 5 mg/ml for algal fatty acids (fas) (cakmak et al., 2014) . the antimicrobial potential of this alga has been attributed to its very valuable fa content, with an x3/x6 ratio equal to 2.15, higher than the proportion found in some fish (cakmak et al., 2014) . this is in agreement with the studies of ohta et al. (1994) , which emphasize the antimicrobial potential of fa-rich oil extracted from the microalga chlorococcum hs-101 against another important methicillin-resistant gram-positive bacterium, s. aureus. the antimicrobial potential of myagropsis myagroides (sargassaceae family in phaeophyta) against l. monocytogenes kctc 3569 was assessed by lee, kim, lim, and ahn (2014). this macroalga revealed antimicrobial activity against gram-positive bacteria, and the ethanolic extract was effective with an mic of 0.013 mg/ ml against l. monocytogenes. a liquid-liquid technique was used to obtain five fractions, and the chloroform (ch 4 ) fraction exerted a strong antimicrobial activity against l. monocytogenes, with an mic of 0.031 mg/ml. the effects of these fractions were analyzed by means of transmission electron microscopy (tem), which detected serious damage to the cell envelope, leading to leakage of cytoplasmic material. a significant release of adenosine triphosphate (atp) (>10 -6 m atp) was also observed in the ch 4 -treated bacterial population, and this was defined as one of the main causes of bacterial death. with regard to the antifungal effects of macro-and microalgae, there is a particularly important study by indira, balakrishnan, srinivasan, bragadeeswaran, and balasubramanian (2013) that assesses the antimicrobial potential of a seaweed (halimeda tuna) against a wide range of foodborne pathogens, including nine fungi: aspergillus niger, aspergillus flavus, alternaria alternaria, candida albicans, epidermophyton floccosum, trichophyton mentagrophytes, trichophyton rubrum, penicillium spp., and rhizopus spp. according to that study, the minimum fungicidal concentration (mfc) of all the seaweed extracts studied (ethanolic, methanolic, and chloroform extracts) was 500 mg/ml, while aqueous extracts had an mfc value ranging between 250 and 500 mg/ml. it can be concluded that h. tuna extracts were very effective against a. niger, a. flavus, a. alternaria, c. albicans, and e. floccosum, and the methanol extract was the most effective one against fungi. salem et al. (2014) studied the antimicrobial potential of nostoc spp., microcystis spp., scenedesmus spp., oscillatoria geminata, and chlorella vulgaris algal strains against several food bacteria, including aspergillus niger. dried algal biomass was sonicated and extracted with 95% methanol and 95% acetone. extracts were prepared in dmso for evaluation of antimicrobial activity. algal extracts from nostoc spp., microcystis spp., scenedesmus spp., and oscillatoria geminata revealed antifungal activity, and the methanol extract of nostoc (50 mg/ml) was the most effective one against a. niger, with an inhibition zone diameter of 22 mm. acetone extract was also effective against a. niger (30 mg/ml), with a 21 mm inhibition zone diameter. an acetone extract of t. conoides also exerted a mild antimicrobial capability against a. niger, with an inhibition zone diameter close to 3 mm (manivannan et al., 2011) . extracts of trichodesmium erythraeum (hexane and ethyl acetate 5 mg/disc) were also effective against a. niger and a. flavus. in a comparison of the hexane and ethyl acetate extracts, the latter had a higher antifungal potential than the hexane algal extract. ethyl acetate extract of t. erythraeum inhibited growth of a. niger and a. flavus at 1000 mg/ml (thillairajasekar, duraipandiyan, perumal, & ignacimuthu, 2009) . both extracts are rich in myristic, oleic, linoleic, and linolenic acids. there is an established relationship between the richness in polyunsaturated fatty acids (lauric, palmitic, linoleic, linolenic, stearic, and myristic) of algal extracts and the antibacterial, antiviral and antifungal potential exerted by them (el shoubaky & el rahman-salem, 2014) . the antifungal potential of two brown seaweeds was also tested against a. niger by manivannan et al. (2011) . according to their results, padina gymnospora chloroform, ethanol, and ethyl acetate extracts were extremely effective in inhibiting a. niger growth (inhibition zone [15] [16] [17] mm). on the other hand, a smaller antifungal potential was attributed to t. conoides extracts (3-11 mm), the only noteworthy result being the inhibition observed after exposure of a. niger cells to diethyl ether t. conoides extract, with an inhibition zone diameter equal to 11 mm. the antifungal activity of seaweed extracts has also been related to the presence of phenolic compounds and their impact on spore germination. some algal extracts have also been shown to inhibit fungal enzyme activity owing to the presence of bioactive metabolites (salem, galal, & el-deen, 2011) . there is a serious lack of information about the antiviral potential of algae against foodborne viruses. mainly, noroviruses (novs) and other commonly viral contaminants in food (hepatitis a (hav), human rotavirus (hrv), hepatitis e virus (hev), nipah virus, highly pathogenic avian influenza (hpai) virus, sarscausing coronavirus) are of high concern for the scientific community (koopmans, 2012) . the main substances from algae that have been related to antiviral potential are sulfated polysaccharides, including fucoidan, sulfoglycolipids, carrageenans, sesquiterpene hydroquinones, etc. (elizondo-gonzalez et al., 2012) . suppression of dna replication and inhibition of host cell colonization by the virus are some of the effects of algal polysaccharides (e.g. fucan, laminaran, and naviculan) as natural antiviral compounds (ahmadi, moghadamtousi, abubakar, & zandi, 2015) . focused on foodborne viruses inhibition by marine algae it is remarkable the research work of wang, wang, and guan (2012) . the study of wang et al. (2012) reviewed the anti-viral potential of polysaccharides from brown seaweeds, mainly alginates and fucans, revealing a significant inhibiting activity against hepatitis b virus (hbv) dna polymerase, and consequently affecting its replication. algae polysaccharides have exerted also anti-viral potential against rotaviruses. these viral agents are the most important causing gastroenteritis, mainly in children, with fatal consequences. the effect of sulfated polysaccharides interfering with the adsorption process of enveloped viruses has been considered in the invention developed by anderson, schaller, mazer, and kirchner (1997) to demonstrate that carrageenan, and particularly k-carrageenan, is an effective inhibitor of rotavirus infection in animal cells. crude metanol extract (70% v/v) of spirulina platensis also showed antiviral activity with 56.7%, inhibition rate against rotavirus wa strain (hetta et al., 2014) . according to the studies of hetta et al. (2014) , free fatty acids (ffa) -induced endoplasmic reticulum (er) stress and suppressor of cytokine signaling protein (socs3) levels are the two main factors responsible for the signaling reduction and impairing the antiviral response. according to the studies of eom et al. (2015) phlorotannins from eisenia bicyclis showed a strong antiviral potential against norovirus (murine norovirus, mnv), with 50% effective concentration (ec 50 ) of 0.9 lm. the inhibition of oxidative phosphorylation, and the ability of phlorotannins to bind with proteins, such as enzymes and cell membranes, are the main causes explaining the antiviral activity of these compounds, that finally act causing cell lysis (shannon & abu-ghannam, 2016) . although the high anti-viral potential of algae compounds (ffa and polysaccharides, mainly) against clinical and foodborne viruses, scarce information has been reported up to date (shannon, 2016; wang et al., 2012) . more research is need to cover the self-evident gap in knowledge regarding the anti-viral applications of algae compounds from both approaches, pharmaceutical and food safety. a wide variety of algae have been introduced in food formulations for various purposes. meat, dairy, and bakery products are some of the best-known examples of innovative products that include these healthy vegetable ingredients. in europe, for a long time interest in algae has focused on the extraction of phycocol-loids with gelling, thickening, and stabilizing properties for use in many applications in the food industry (enzing, ploeg, barbosa, & sijtsma, 2014) . the main limitations affecting the application of algae in food products are related to sensory (residual flavor and aroma) and toxicological aspects (high iodine levels, or accumulation of arsenic, heavy metals, and contaminants) (bouga & combet, 2015) . these risks must be minimized in order to maximize the technological, functional, and nutritional advantages that are associated with macro-and microalgae materials and bioactive compounds. the introduction of microalgae in animal feed has been a reality since the '70 s, and is a good way to improve animal health and the subsequent quality of meat-derived products. in aquaculture feed, algae supplements are also being used, with good prospects (yaakob, ali, zainal, mohamad, & takriff, 2014) . in food for human consumption, seaweed has been introduced in breads, pizza bases, and cheese (e.g. ascophyllum nodosum) (hall, baxter, fryirs, & johnson, 2010) , and has also been added to pasta (e.g. sargassum marginatum)) (prabhasankar et al., 2009) and meat products (cofrades, lópez-lópez, ruiz-capillas, triki, & jiménez-colmenero, 2011) . the development of algae-based lipid powders and flours is also one of the hot topics that has been included in novel cuisine, and they are even being used instead of eggs, with really promising results for the vegan market. however, with regard to preservation there is scarce literature about validating the functionality of these ingredients as antimicrobials in real food matrices (gupta et al., 2010; sȃlȃgean, pop, catrinoi, & nagy, 2015) . although some researchers are making efforts to introduce raw algae and processed materials in the formulation of innovative meat-derived products (e.g. sausages and hamburgers), some aspects such as quality and organoleptic acceptance of the final formulation still need to be analyzed in depth. with regard to the validation of the antimicrobial potential of algae in meat products, a noteworthy study has recently been published by sȃlȃgean et al. (2015) . among the main advantages that the introduction of algae in meat-formulated products aims at are the following: (a) the introduction of a protein source of vegetable origin, (b) lower content of cholesterol, calories and fat in the finished products, and the associated (c) beneficial bioactive compounds present in algae-derived ingredients. according to the results obtained by sȃlȃgean et al. (2015) , in the formulation of half-smoked sausages (75% first-quality beef, [10-15]% animal fat, and brown algae [10-15]%) the addition of algae in the formulation led to a final product with higher quality (physicochemical and organoleptic), with improved functionality resulting from the antimicrobial potential of brown algae against s. aureus and e. coli (storage 7 days, 10-12°c). furthermore, a recent industrial patent has been obtained for the introduction of algae in meatderived products. according to cofrades et al. (2011) , a new method for the formulation of healthier meat products has been developed, incorporating less than 5 wt.% of himanhatalia elongata brown alga. brown algae are more suitable for meat formulations than red or green algae, not only because of their nutritional profile but also because of the color balance between animal tissue (cattle, pigs, sheep, goats, horses, poultry) and these pigmented algae. the result shows a reduction in sodium levels and an improvement in the lipid profile of the final product (cofrades et al., 2011) . the antimicrobial capability of macroalgae has been reported to reduce the need for the addition of salt, especially against gramnegative bacteria. a reduction of nearly 1 log 10 cycle was observed against coliforms during the shelf life of frozen processed meat products (brownlee, fairlough, hall, & paxman, 2012) . similarly, in bread products the antifungal potential of green seaweed added to bakery products suppressed mold growth for up to 9 days in preservative-free bread, equivalent to the control bread containing 5 g of sodium chloride (brownlee et al., 2012) . in the research line of novel meat products with longer shelf life, edible films and coatings (efc) are a promising preservation technology that provides a good barrier against spoilage and pathogenic microorganisms when natural antimicrobials are added. according to sánchez-ortega et al. (2014) , the addition of edible algae films and coatings on meat products had the following main advantages: reduction of lipid oxidation, increase in stability of red meat color, prevention of moisture loss, reduction of spoilage and pathogenic microorganism load, and partial inactivation of deteriorative proteolytic enzymes on the surface of the coated meat. the development of red algae films applied to bacon impacted positively on the microbiological quality of the product reducing e. coli o157:h7 by 0.45 log cfu/g and l. monocytogenes by 0.76 cfu/g with respect to the controls. the application of edible coatings from algae to cheese also reduced e. coli o157:h7 and l. monocytogenes populations by 1.21 and 0.85 log cfu/g, respectively, compared with the control after 15 days of storage (shin, song, seo, & song, 2012; sánchez-ortega et al., 2014) . other algae derivatives such as alginate and j-carrageenan have also been used in the formulation of edible films with antimicrobial properties against l. monocytogenes, e.g. in cold smoked salmon (neetoo, ye, & chen, 2010) . effective antimicrobial potential has been demonstrated against foodborne pathogens by both macro-and microalgae compounds. however, some contradictions can be found in the literature as a result of the different strains used in the determination of antimicrobial activity, different methods of extraction applied, and different ranges of alga material concentration used in the assays. the promising results of bacterial growth inhibition and inactivation by raw and purified algal compounds, and the lack of studies carried out in real food matrices open a research niche with high application at food industrial level. a valuable relationship could be established between the antioxidant potential of algae and their antimicrobial capability. consequently, the twofold use of algae extracts as antioxidants and antimicrobials in food products has good prospects in response to the horizon 2020 call for 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escherichia coli to seaweed (ascophyllum nodosum) phlorotannins and terrestrial tannins y an overview: biomolecules from microalgae for animal feed and aquaculture key: cord-336578-5qzpd890 authors: sethiya, jigar p.; sowards, melanie a.; jackson, mary; north, elton jeffrey title: mmpl3 inhibition: a new approach to treat nontuberculous mycobacterial infections date: 2020-08-27 journal: int j mol sci doi: 10.3390/ijms21176202 sha: doc_id: 336578 cord_uid: 5qzpd890 outside of mycobacterium tuberculosis and mycobacterium leprae, nontuberculous mycobacteria (ntm) are environmental mycobacteria (>190 species) and are classified as slowor rapid-growing mycobacteria. infections caused by ntm show an increased incidence in immunocompromised patients and patients with underlying structural lung disease. the true global prevalence of ntm infections remains unknown because many countries do not require mandatory reporting of the infection. this is coupled with a challenging diagnosis and identification of the species. current therapies for treatment of ntm infections require multidrug regimens for a minimum of 18 months and are associated with serious adverse reactions, infection relapse, and high reinfection rates, necessitating discovery of novel antimycobacterial agents. robust drug discovery processes have discovered inhibitors targeting mycobacterial membrane protein large 3 (mmpl3), a protein responsible for translocating mycolic acids from the inner membrane to periplasm in the biosynthesis of the mycobacterial cell membrane. this review focuses on promising new chemical scaffolds that inhibit mmpl3 function and represent interesting and promising putative drug candidates for the treatment of ntm infections. additionally, agents (fs-1, smart-420, c10) that promote reversion of drug resistance are also reviewed. nontuberculous mycobacteria (ntm) are mycobacteria, other than mycobacterium tuberculosis (m. tb) and mycobacterium leprae, the causative agent for tuberculosis (tb) and leprosy, respectively, that are environmental pathogens and are commonly found in soil, dust, biofilms, and natural and municipal water sources. ntm are also described in literature as atypical mycobacteria or mycobacteria other than tuberculosis (mott) [1] . to quinolones, beta-lactams, and aminoglycosides. inducible resistance occurs through induced expression of erythromycin resistance methylase (erm) genes, which result in the translation of a methylase that weakens the binding of macrolides with the bacterial ribosomes. acquired resistance by mutations in the 23s rrna (rrl), 16s rrna (rrs), and rpob genes of the ntm species causes high-level resistance to the macrolides and linezolid, aminoglycosides, and rifampicin, respectively. bedaquiline also shows acquired resistance against mac pulmonary disease through the regulator gene of the mmps5/mmpl5 efflux system, and this mutation results in cross-resistance to clofazimine [26] . resistance occurs through induced expression of erythromycin resistance methylase (erm) genes, which result in the translation of a methylase that weakens the binding of macrolides with the bacterial ribosomes. acquired resistance by mutations in the 23s rrna (rrl), 16s rrna (rrs), and rpob genes of the ntm species causes high-level resistance to the macrolides and linezolid, aminoglycosides, and rifampicin, respectively. bedaquiline also shows acquired resistance against mac pulmonary disease through the regulator gene of the mmps5/mmpl5 efflux system, and this mutation results in cross-resistance to clofazimine [26] . the increasing incidence, limited efficacy of current treatment options, and significant risk of drug-resistance in ntm infections suggest an urgent need for new antimycobacterial agents. while several drug candidates, such as inhaled nitric oxide gas, gallium nitrate, interferons, il-12, clofazimine, bedaquiline, rifabutin, amithiozone, linezolid, tedizolid, and tigecycline, are under clinical trials for ntm infections, most of them are repurposed antibiotics drugs used for tb or other bacteria. the drug discovery pipeline is primarily focused on efficacy against tb, with few trials assessing agents effective for treatment of ntm infections. recently developed compounds targeting the mmpl3 transporter, a new and promiscuous target recognizing many structurally unique chemotypes, have proven to be effective in both tb and ntm infections. in this review, we focus on potential new compounds that inhibit mmpl3 with efficacy against ntm species. the mycobacterial cell wall is different from the gram-positive and -negative bacterial cell wall [27] . it is a complex structure, made up of covalently linked mycolic acids (ma)-peptidoglycan (pg)arabinogalactan (ag) (also known as magp) [28] . the peptidoglycan is the innermost layer and mycolic acids are the outermost layer of the mycobacterial cell wall [28] . mycolic acids are a major component and are considered a hallmark of the mycobacterial cell wall [27, 29, 30] . mycolic acids comprise a highly impermeable lipid-rich layer that protects the mycobacterial cell against various threats including antibiotics and the host's immune system and also contributes to virulence [30, 31] . chemically, mycolic acids are α-alkylalted, β-hydroxylated long-chain fatty acids. the α-alkyl chain comprises saturated c22-c26 carbons, and the β-hydroxy long meromycoloyl chain comprises c42-c62 carbons [32] . depending on the functional groups attached, the mycolic acids found in m. tb can be differentiated into α-, methoxy-, keto-, and/or hydroxy-mycolic acids. there are in total c66-c90 carbons in a mycolic acid chain length [27, 30] . even though mycolic acids are found in all mycobacterial pathogens and provide similar cellular protection, structural integrity, and virulence, the increasing incidence, limited efficacy of current treatment options, and significant risk of drug-resistance in ntm infections suggest an urgent need for new antimycobacterial agents. while several drug candidates, such as inhaled nitric oxide gas, gallium nitrate, interferons, il-12, clofazimine, bedaquiline, rifabutin, amithiozone, linezolid, tedizolid, and tigecycline, are under clinical trials for ntm infections, most of them are repurposed antibiotics drugs used for tb or other bacteria. the drug discovery pipeline is primarily focused on efficacy against tb, with few trials assessing agents effective for treatment of ntm infections. recently developed compounds targeting the mmpl3 transporter, a new and promiscuous target recognizing many structurally unique chemotypes, have proven to be effective in both tb and ntm infections. in this review, we focus on potential new compounds that inhibit mmpl3 with efficacy against ntm species. the mycobacterial cell wall is different from the gram-positive and -negative bacterial cell wall [27] . it is a complex structure, made up of covalently linked mycolic acids (ma)-peptidoglycan (pg)-arabinogalactan (ag) (also known as magp) [28] . the peptidoglycan is the innermost layer and mycolic acids are the outermost layer of the mycobacterial cell wall [28] . mycolic acids are a major component and are considered a hallmark of the mycobacterial cell wall [27, 29, 30] . mycolic acids comprise a highly impermeable lipid-rich layer that protects the mycobacterial cell against various threats including antibiotics and the host's immune system and also contributes to virulence [30, 31] . chemically, mycolic acids are α-alkylalted, β-hydroxylated long-chain fatty acids. the α-alkyl chain comprises saturated c 22 -c 26 carbons, and the β-hydroxy long meromycoloyl chain comprises c 42 -c 62 carbons [32] . depending on the functional groups attached, the mycolic acids found in m. tb can be differentiated into α-, methoxy-, keto-, and/or hydroxy-mycolic acids. there are in total c 66 -c 90 carbons in a mycolic acid chain length [27, 30] . even though mycolic acids are found in all mycobacterial pathogens and provide similar cellular protection, structural integrity, and virulence, subtle differences in carbon chain length an composition are found. for example, at the time when this review was written, keto-and methoxy-ma have not been detected in m. phlei, [29] , yet are common in m. tb. these structural differences may account for the variations in drug susceptibility among mycobacterial pathogens. the biosynthetic pathway of mycolic acids involves many catalytic enzymes that synthesize and functionalize long fatty chains that are condensed together, transported out and attached to the outer membrane ( figure 2 ). the biosynthesis of mycolic acids initially involves two enzyme complexes: fatty-acid synthase-i (fas-i) and fatty-acid synthase-ii (fas-ii). fas-i initiates de novo fatty acid synthesis cycle from an acetyl group to produce c [16] [17] [18] and c 24-26 acyl coas [29] . each cycle of fas-i synthase undergoes the addition of two new carbon atoms, thereby increasing the chain length [30] . fas-ii further elongates the short chain c 12-16 fatty acids to c 18-30 acyl-acyl carrier proteins (acps) [29] . fas-i synthesizes hexacosanoyl-coa (c 26 ) that ultimately becomes the α-chain of mycolic acids [30] . β-ketoacyl-acp-synthase iii (mtfabh) initiates the fatty acid synthesis by combining malonyl-acp and acyl-coa through claisen condensation. the product formed is β-ketoacyl-acp, followed by a reduction to β-hydroxyacyl-acp by β-ketoacyl-acp reductase (maba). β-hydroxyacyl-acp dehydratases (hadab and hadbc) convert the β-hydroxyacyl-acp into an enoyl-acp. this enoyl-acp is reduced to an acyl-acp by nadh-dependent trans-2-enoyl-acp reductase (inha). this acyl-acp is again taken up into the fas-ii cycle and further elongated until a mero-mycolic acid chain is formed. it is thought to undergo five cycles for alpha-mycolic acids and eight cycles for methoxyand keto-mycolic acid. elongation of the fatty acid chain takes place by β-ketoacyl-acp-synthase (kasa or kasb). marrakchi et al. report inha, maba, hadb, and kasa as essential proteins [29] . in addition, kasb is essential for the full extension of the mycolic acids, the acid-fastness property of the mycobacteria, and production of ketomycolic acids [27, 33] . the addition of cyclopropanes to the meromycolic acid is catalyzed by the s-adenosyl-methionine (sam)-dependent methyltransferases. cmaa1, cmaa2, pcaa, and mmaa2 are the methyltransferases identified in m. tb [29] , however, the exact ntm enzymes have not been determined. the product from the fas-i is carboxylated by accd4 (acyl-coa carboxylase) [29] , as accd4 and accd6 are essential genes in m. tb [34] . before the final condensation with the short α-chain, the long-chain meromycolic acid (c 50-60 ) gets activated through the fadd32 enzyme. fadd32 (fatty acid adenylating enzyme) is a member of the fatty acyl-amp ligase (faal) class that activates and transfers the activated long chain acyl adenylate to the pantetheine moiety of the n-terminal acyl carrier protein (acp) domain of polyketide synthase 13 (pks13) [29, 35] . pks13 is a member of the type-i pks family and is responsible for performing the final condensation step in the production of mycolic acids. the five domains of the pks13 are peptidyl carrier protein (pcp)-like domain, ketoacyl synthase (ks), acyl transferase (at), acp domain, and thioesterase (te). 4 -phosphopantetheinyl transferase pptt is essential for the activation of the acp and pcp domains of pks13 [29] . after the final condensation step, a reduction mediated through cmra produces mature mycolic acids and their pks13-mediated transfer to trehalose to form trehalose monomycolate (tmm) [29] . after acetylation of the β-hydroxy group on tmm by tmat, tmm is transported out of the cytoplasm to the periplasmic space through the mmpl3 transporter [36, 37] . subsequently, this glycolipid serves as a donor of mycolic acyl chains that either form a covalent linkage with the arabinogalactan layer of magp or esterify another molecule of tmm to form the outer membrane glycolipid, trehalose dimycolate (tdm, also known as cord factor) [38, 39] . the enzyme responsible for the transesterification of mycolic acids from tmm to their cell envelope acceptors are the mycolyltransferases (ag85 complex), fbpa, fbpb, and fbpc (also known as ag85a, ag85b, and ag85c). ag85c helps in the formation of magp whereas ag85a and ag85b help in the formation of tdm [32] . although tdm is present mainly as the outer layer, phthiocerol dimycocerosate (pdim) and a number of other acyltrehaloses (sulfolipids, diacyl-, and poly-acyltrehaloses) also contribute to form an outer layer [39] . mmpl3 transporters aid in the translocation of tmm across the plasma membrane for cell envelope biosynthesis. mmpl3 belongs to the resistance-nodulation-cell division (rnd) protein superfamily of inner membrane transporters. its translocation activity is dependent on the proton motive force (pmf). on the basis of a spheroplast-based translocation assay that can determine the topology of tmm in the plasma membrane, xu and colleagues proposed that mmpl3 functions as a tmm flippase [40] . in the mmpl family, mmpl3 is an essential mmpl transporter indicating that its function is unique. co-crystallography and native mass spectrometry studies indicated that mmpl3 not only binds tmm but also phospholipids such as phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin suggesting that it might be involved in the translocation of more than one lipid to the periplamic space [39] . determination of the crystal structure of mmpl3 from m. smegmatis indicates that mmpl3 functions as a monomer [39, 41] . although this observation is contradictory to earlier gel filtration and single-particle electron microscopy studies indicating that mmpl3 and its ortholog in corynebacterium glutamicum (cmpl1) form trimers, the same way prototypical rnd transporters from gram-negative bacteria do [42] . we believe this discrepancy to be due to the fact that the recombinant forms of mmpl3 that were crystallized were devoid of their cytoplasmic c-terminal domain which our preliminary results indicate is required for the proper oligomerization of the transporter [43] . the mmpl3 transporter is essential for the biosynthesis of tdm and the mycolylation of the cell wall arabinogalactan that are required for the replication and viability of mycobacterial cells. genetic or chemical silencing of mmpl3 leads to rapid cell death in vitro and the same is observed in cellular and in vivo acute infection models [44, 45] . therefore, mmpl3 is considered as an attractive drug target [38, [46] [47] [48] . the mmpl3 ortholog from m. tb is 99%, 64%, and 56% identical to the mmpl3 orthologs of m. bovis, m. smegmatis, and m. abscessus, respectively [49] . inhibition of the mmpl3 transporter results in the accumulation of tmm concentrations intracellularly, and a reduction in the levels of magp and tdm [36, 37, 39, 41] . there have been two proposed mechanisms by which an inhibitor can act on mmpl3. the first is that the inhibitor blocks the translocation of the tmm by directly binding to the transporter. the second mmpl3 transporters aid in the translocation of tmm across the plasma membrane for cell envelope biosynthesis. mmpl3 belongs to the resistance-nodulation-cell division (rnd) protein superfamily of inner membrane transporters. its translocation activity is dependent on the proton motive force (pmf). on the basis of a spheroplast-based translocation assay that can determine the topology of tmm in the plasma membrane, xu and colleagues proposed that mmpl3 functions as a tmm flippase [40] . in the mmpl family, mmpl3 is an essential mmpl transporter indicating that its function is unique. co-crystallography and native mass spectrometry studies indicated that mmpl3 not only binds tmm but also phospholipids such as phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin suggesting that it might be involved in the translocation of more than one lipid to the periplamic space [39] . determination of the crystal structure of mmpl3 from m. smegmatis indicates that mmpl3 functions as a monomer [39, 41] . although this observation is contradictory to earlier gel filtration and single-particle electron microscopy studies indicating that mmpl3 and its ortholog in corynebacterium glutamicum (cmpl1) form trimers, the same way prototypical rnd transporters from gram-negative bacteria do [42] . we believe this discrepancy to be due to the fact that the recombinant forms of mmpl3 that were crystallized were devoid of their cytoplasmic c-terminal domain which our preliminary results indicate is required for the proper oligomerization of the transporter [43] . the mmpl3 transporter is essential for the biosynthesis of tdm and the mycolylation of the cell wall arabinogalactan that are required for the replication and viability of mycobacterial cells. genetic or chemical silencing of mmpl3 leads to rapid cell death in vitro and the same is observed in cellular and in vivo acute infection models [44, 45] . therefore, mmpl3 is considered as an attractive drug target [38, [46] [47] [48] . the mmpl3 ortholog from m. tb is 99%, 64%, and 56% identical to the mmpl3 orthologs of m. bovis, m. smegmatis, and m. abscessus, respectively [49] . inhibition of the mmpl3 transporter results in the accumulation of tmm concentrations intracellularly, and a reduction in the levels of magp and tdm [36, 37, 39, 41] . there have been two proposed mechanisms by which an inhibitor can act on mmpl3. the first is that the inhibitor blocks the translocation of the tmm by directly binding to the transporter. there are no fda-approved and marketed antibiotics that inhibit mmpl3. however, mmpl3 inhibitors do not share a common pharmacophore, suggesting that mmpl3 is a promiscuous drug target [53] . this article focuses on the new scaffolds of mmpl3 inhibitor found to be active against ntm species. there are no fda-approved and marketed antibiotics that inhibit mmpl3. however, mmpl3 inhibitors do not share a common pharmacophore, suggesting that mmpl3 is a promiscuous drug target [53] . this article focuses on the new scaffolds of mmpl3 inhibitor found to be active against ntm species. indole-2-carboxamide derivatives are one of the most extensively studied classes of the mmpl3 inhibitors. the compounds of this class show potent action against m. tb and ntm species. the nitd compounds (shown in figure 3 ) are previously reported indole-2-carboxamides under preclinical evaluation [54] . structurally, the compound consists of an indole ring at the left-hand side (lhs) and a cycloaliphatic group at the right-hand side (rhs) connected through an amide linkage. the compounds containing indole-2-carboxamide pharmacophore are additionally reported to be effective against drug-susceptible and drug-resistant tb [55] . in 2017, franz and colleagues reported series of indole-2-carboxamides with activity against ntm species including m. abscessus, m. bolletti, m. massiliense, m. avium, m. smegmatis, and m. cholenae [56] . the compounds were synthesized into two miniseries: unsubstituted indoles and 4,6-dimethyl substituted indoles. from the first series, adamantyl-and isopinocampheyl-containing unsubstituted indoles show activity against rgm with mic <1 µ g/ml, except m. smegmatis. from the second series, the compound with the highest potency contained a cyclooctyl ring and 4,6-dimethyl indole (1, table 1 ), having an activity ranging from 0.0039 to 0.6 µ g/ml against rgm. compounds with cycloheptyl, isopinocampheyl, and 4-methylcyclohexyl head groups also showed significant activity against mycobacteria. replacing the head group with an aliphatic long chain, phenyl ring, or surprisingly, adamantyl group rendered the compound ineffective. compound 1 is also active against sgm m. avium with mic = 0.05-1 µ g/ml and m. xenopi with mic = 0.25 µ g/ml. in vitro cytotoxicity studies show no toxicity against thp-1 cells and the selectivity index (si) of >1910 for m. abscessus, m. massiliense, and m. bolletii [56] . in vivo studies with 1 conducted in mice demonstrated good oral bioavailability and were efficacious in m. abscessus infected mice [57, 58] . compound 1 was also indole-2-carboxamide derivatives are one of the most extensively studied classes of the mmpl3 inhibitors. the compounds of this class show potent action against m. tb and ntm species. the nitd compounds (shown in figure 3 ) are previously reported indole-2-carboxamides under preclinical evaluation [54] . structurally, the compound consists of an indole ring at the left-hand side (lhs) and a cycloaliphatic group at the right-hand side (rhs) connected through an amide linkage. the compounds containing indole-2-carboxamide pharmacophore are additionally reported to be effective against drug-susceptible and drug-resistant tb [55] . in 2017, franz and colleagues reported series of indole-2-carboxamides with activity against ntm species including m. abscessus, m. bolletti, m. massiliense, m. avium, m. smegmatis, and m. cholenae [56] . the compounds were synthesized into two miniseries: unsubstituted indoles and 4,6-dimethyl substituted indoles. from the first series, adamantyl-and isopinocampheyl-containing unsubstituted indoles show activity against rgm with mic <1 µg/ml, except m. smegmatis. from the second series, the compound with the highest potency contained a cyclooctyl ring and 4,6-dimethyl indole (1, table 1 ), having an activity ranging from 0.0039 to 0.6 µg/ml against rgm. compounds with cycloheptyl, isopinocampheyl, and 4-methylcyclohexyl head groups also showed significant activity against mycobacteria. replacing the head group with an aliphatic long chain, phenyl ring, or surprisingly, adamantyl group rendered the compound ineffective. compound 1 is also active against sgm m. avium with mic = 0.05-1 µg/ml and m. xenopi with mic = 0.25 µg/ml. in vitro cytotoxicity studies show no toxicity against thp-1 cells and the selectivity index (si) of >1910 for m. abscessus, m. massiliense, and m. bolletii [56] . in vivo studies with 1 conducted in mice demonstrated good oral bioavailability and were efficacious in m. abscessus infected mice [57, 58] . compound 1 was also identified as a screening hit performed by low and colleagues, where 1 is reported as mmv687146 with mic 50 = 0.8 µg/ml [59] . the sar was further explored by replacing the 4,6-dimethyl groups with halogen functional groups. as aromatic methyl groups are vulnerable to cyp-mediated benzylic oxidation, replacing them with halogens may result in compounds with higher metabolic stability and similar lipophilicity when compared to previous series [60, 61] . from the series of compounds tested, 2, 3, and 4 showed activity similar to compound 1 against m. abscessus, with mic values of 0.125 µg/ml. compound 2 is a 4,6-dichloro substituted indole, whereas 3 is a 4,6-difluoro substituted indole. compound 4 retains similar activity as a monosubstituted 6-bromo-indole. a 4,6-dibromo-substituted indole was not studied. the bulkier cyclooctyl ring is optimal for the activity against m. abscessus [62] . variation in the amide linkage can result in loss of activity. linking functionalities including ketoamide, oxamide, 1,1-diamide-amine, and thiazole-2-amide were assessed against m. tb but did not improve activity [60] . compounds 2 and 4 were found to be equally effective against 30 clinical strains including smooth (s) and rough (r) variants isolated from the cf and non-cf patients. both compounds act by inhibiting tmm transport and lack activity against ag85 complex enzymes. compound 2 has the capacity to permeate human macrophages to elicit its action. however, the adme properties of 2 show low permeability, high plasma protein binding, and high intrinsic clearance. in addition, the mmpl3 a309p mutant shows high resistance to 2 [62] . [63] . this interesting scaffold is thought to act pleiotropically, having multiple other cell membrane-embedded targets, including mmpl3. li and colleagues found that 5 disrupts the pmf which may contribute to the inhibition of mmpl3. in addition to reducing extracellular levels of tdm, it also decreases the level of other cellular lipids. however, 5 does not have a docking pose with the mmpl3 protein, is not cross-resistant with direct mmpl3 inhibitors, and retains activity against the mmpl3 resistant mutants [64] . compound 5 is an optimized analog of sq109, 1-geranylindole or (5-fluoro-[(e)-1-(3,7dimethylocta-2,6-dien-1yl)]-3-(piperidin-1-ylmethyl)-1h-indole) with moderate activity and selectivity (mbc 90 = 12 µm and ic 50 vero = 22 µm). substitutions at the 1-and 3-positions on 5 are essential to maintain antimycobacterial action. various side chains have been assessed at the 1-position, such as n-butyl, n-octyl, 3-cyanopropyl, n-substituted aminocarbonylmethyl, benzyl, phenpropyl, phenoxypropyl, and cyclohexylethyl. optimal action is produced by the n-octyl side chain. moreover, an increase in chain length up to 12 carbons does not affect the activity. next, the substitution of the saturated cyclic ring at the third position is important. replacement of the azepane ring with an aliphatic chain with a tertiary nitrogen decreases the activity. substitution with cyclopropyl or cyclopentyl causes a small drop in the activity, whereas 4-methylpiperidine and n-methyl cycloheptylamine retain activity. while morpholine, piperazine, and thiazine groups decrease the activity, the 1,4-dioxa-8-azaspiro [4.5] decane (m. bovis mic 90 = 5 µm) shows higher activity than 5 (m. bovis mic 90 = 6 µm). replacing the fluoro group with chloro, bromo, or methoxy maintains the activity. however, the position of the groups correlates with the activity. azaspiroketals with 6-methoxy substitutions are potent, whereas azapenes with 4-fluoro substitutions are potent compounds [63] . despite being active against mycobacteria, 5 also has activity against the gram-positive bacteria s. aureus (mic 50 = 8 µm), but is not active against the gram-negative bacteria e. coli, suggesting 5 interacts with additional pharmacological targets. however, 5 has some toxicity against hepg2 and vero cell lines (ic 50 = 19.2 µm and 29.2 µm, respectively). in vitro studies determined moderate solubility (35.9 µm) and good metabolic stability with a half-life of 560 min tested on rat liver microsomes [63] . considering the promising activity against m. avium, further optimization of this scaffold is warranted to reduce potential for toxicity. additionally, the azaspiroketal derivatives were found to be more potent than 5 against m. tb and directly bind mmpl3, as supported by cross-resistance with other mmpl3 inhibitors. in vivo pharmacokinetic studies in murine models have been reported, proving promising adme parameters, and screens against ntm species should be pursued [64, 65] . in 2014, gobis et al. reported 6 as an antimycobacterial agent with activity against m. tb and m. bovis [66] . the mechanism of action for this compound was later identified as mmpl3 inhibition [67] . recent in vitro studies of benzimidazole derivatives show bacteriostatic action of 6 against m. abscessus clinical isolates including s and r variants from cf and non-cf patients. unlike the optimal 4,6-disubstitution patterned indole-2-carboxamides, the highly potent compounds from this series are 5,6-disubstituted benzimidazoles. in addition, this series lacks the amide side chain and the bulky cycloaliphatic group such as cyclooctyl, adamantyl which is thought to be a characteristic feature of mmpl3 inhibitors. despite this, 6 has similar activity to that of previously reported indoles 2, 3, and 4 (mic = 0.125 µg/ml). similar to indole-2-carboxamides, the nh hydrogen is required to form an h-bond with the mmpl3 transporter. replacement of the hydrogen with the aryl sulfonyl group results in inactivity. in contrast to indole-2-carboxamide derivatives, mono-substitution at the 6 position of the phenyl ring of benzimidazole significantly decreases the activity. increasing the length or degree of unsaturation of the chain also decreases the activity. a small mini-series with a phenyl group replacing the cyclohexyl group on the rhs was also assessed. all compounds within the series were inactive except one with a 3,5-dichlorophenyl having the mic = 0.25 µg/ml [68] . benzimidazole derivatives show acceptable cytotoxicity with si of 712 against thp-1 macrophages. compound 6 decreases the intracellular bacterial load in infected macrophages and in embryonic zebrafish models. however, the study reveals that many mmpl3 mutants are resistant to benzimidazole derivatives. in assessing the mmpl3 mutants, the potency drops >64-fold for the a309p mutant while a 4-to 8-fold drop is seen for the other mutants. however, greater resistance was seen against au1235 than for 6. of note, 2 (indole-2-carboxamide) is effective against all mmpl3 mutants, except the a309p mutant. compound 6 is cross-resistant with compound 13 (piperidine derivative) but not with sq109. it is assumed that 6 acts by direct mmpl3 inhibition, based on the available data. all reported mutants, except v299a, have mutations located far from the binding site of mmpl3. it is thought that mutations in mmpl3 can induce long-distance structural rearrangements that can result in reduced drug-binding affinity [50, 68] . william and colleagues identified mmpl3 inhibitors through high-throughput screening. of the hit compounds, two contain the benzimidazole pharmacophore. compound 7, 2-[(5-chloro-1h-benzimidazol-2-yl)sulfanyl]-n,n-di(propan-2-yl) acetamide is the only active benzimidazole and was among the most potent compounds identified in the screen against m. abscessus. compound 18 (4-thiophen-2-yloxane-4-carboxamide analog) was the most potent compound against m. abscessus among the hits (described below). compound 7 contains a sulfur group in the amide side chain and lacks the cycloaliphatic ring system, instead having two isopropyl substituents on the amine. it shows 81.8% growth inhibition for m. abscessus at the single concentration of 20 µm (mic 50 = 25µm). the compound is selective against the mycobacteria species and lacks activity against gram-positive and gram-negative bacteria (>200 µm). compound 7 has been shown to disrupt the membrane potential, thereby, suggesting its activity may be through disruption of pmf. the bone marrow murine macrophage cytotoxicity study reveals it as a safe compound (cc 50 > 100 µm). additionally, 7 has good solubility at 178 µm and good microsomal stability of 71% remaining 30 min after administration. benzimidazoles with a 5-methyl instead of a 5-chloro group lack activity against m. abscessus, suggesting the importance of having an electron-withdrawing group on the benzimidazole ring. the methyl group is also susceptible to the cyp-mediated benzylic hydroxylation and resulted in reduced microsomal stability, dropping it from 71% to 25% [48] . recently, dal molin et al. reported additional benzimidazole derivatives, 8 and 9, as putative antimycobacterial agents targeting the mmpl3 transporter. using gfp-based high-throughput screening, several hits were identified against m. tb and m. abscessus. compound 8 showed an mic 90 of 0.98 µm against m. tb. the potency for 8 drops to 62.5 µm against the drug-resistant mutants. compound 9 is cross-resistant to 8, and similarly, has a higher mic of >62.5 µm against 8 resistant mutants. both compounds have an mic 90 of 31.25 µm against m. abscessus. compound 8 was also able to significantly reduce mycobacterial load in an infected macrophage. the pharmacophore for 8 and 9 is an aminobenzimidazole, which differs from 6 and 7. compound 8 differs from 9 by the substitution on the benzimidazole ring. compound 8 is 5,6-dimethyl substituted, whereas 9 is 5-chloro,6-methyl substituted. compound 8 and 9 lack the amide side chain, like 6, and lack the cycloaliphatic group at the rhs, like 7. instead, they each contain a 2-isopropyl-1-aniline ring attached to the 2-benzimidazole. however, 8 shows high toxicity against thp-1 macrophages (15.625 µm) [69] . there is no evidence of how 8 and 9 inhibit mmpl3, direct or indirect. moreover, there are no reported in vivo pharmacokinetic studies for 8 and 9. optimization is required to increase potency against ntm species. graham et al. report 11 as a potent antimycobacterial agent showing activity against m. abscessus atcc 19977, m. avium 101, m. intracellulare 1956, and m. tb h37rv. the pharmacophore of this benzothiazole derivative is different than the two previously discussed. the nh of the benzimidazole is replaced by a sulfur atom, comprising the benzothiazole aromatic ring system. moreover, the amide linkage is reversed here such that the nh of the amide is attached to the benzothiazole ring (lhs) instead of the alicyclic ring (rhs) as seen in other mmpl3 inhibitor classes. compound 11 is an optimized version of the previous hit 10, which contained a dimethylated adamantyl ring (m. abscessus mic = 1 µg/ml, m. avium mic = 2 µg/ml, m. tb mic = 4 µg/ml). various cycloaliphatic groups (rhs) were studied by replacing the adamantyl group because the adamantyl ring is lipophilic and may lead to nonspecific binding. this is a common problem for not only mmpl3 inhibitors, but many antimycobacterial drug discovery efforts as the mycobacterial cell wall is lipid-rich with mycolic acids, leading to initial lipophilic hits that can effectively penetrate the cell wall. out of the screening process, 3, 3, 5-trimethylcyclohexyl group is found to be most effective against m. abscessus. various mono-, di-, and tri-substitution patterns using functional groups such as x, ch 3 , cf 3 , ocf 3 , och 3 , scf 3 , nch 3 , and oh were assessed on the benzothiazole ring (lhs). high activity against m. abscessus was seen in the 5,7 di-substituted and 6 mono-substituted patterns, with halogens such as fluorine and chlorine proving most effective. however, activity is low against other mycobacteria. it was suggested that the 1-methylated cycloaliphatic ring improves activity against rgm and sgm. the 1-methylcycloheptyl derivative shows >530-fold and >8-fold increase in activity against m. abscessus and m. avium compared to that of the unsubstituted cycloheptyl [70] . the ineffectiveness of the unsubstituted cycloheptyl against m. abscessus using cip 104536 susceptible strain is reported in another study [62] . moreover, it retained activity against sgm such as m. avium 101 (2 µg/ml), and m. intracellulare 1956 (2 µg/ml), m. chimaera 1502055 (1 µg/ml), and m. tb h37rv mc 2 6206 (≤0.12 µg/ml). active mmpl3 inhibitors, must be lipophilic enough to penetrate the cell envelope. benzothiazole derivatives exhibited bacteriostatic action against m. abscessus and have no activity against gram-positive and -negative bacteria up to 32 µg/ml. in vitro cyp enzyme inhibition studies show that 11 does not inhibit cyp2b6 and cyp3a4 more than 50% at 10 µm, cyp2b6 and cyp3a4 are the potential cyp enzymes for pulmonary delivery. also, no hemolytic activity was determined. unsurprisingly, this class of compounds suffers from low solubility (<3 µm) and high plasma protein binding (>95%). an in vivo study of 10 using granulocyte macrophage-colony-stimulated factor knockout (gm-csf ko) mice established that there is a reduction of 0.64 log 10 cfu in comparison to the vehicle group, but there is no significant reduction observed when compared to the untreated group [71] . the pharmacokinetics in a mouse model for one of its derivatives show 75% oral bioavailability and 1.5 l/h/kg plasma clearance after iv administration (10 mg/kg). in vivo screening, pharmacokinetic studies, and development of an inhaled formulation is in progress for this class [70] . however, mic assays using clinically isolated s and r variants need to be completed. in 2014, shah and colleagues report n-arylalkylbenzo[d]thiazole-2-carboxamides as anti-mycobacterial agents. these compounds contain the benzothiazole ring as an aromatic group on the lhs and a substituted aromatic phenyl ring on the rhs. unlike indole-2-carboxamides, they contain an additional carbon between the nh amide and the aromatic group on the rhs. most compounds from the series possess a mic range of 3.125-50 µg/ml against m. tb, except two compounds with mics of 0.78 µg/ml (12) and 1.56 µg/ml (not mentioned). compound 12 has low toxicity on the hek-293t (human embryonic 25 kidney cell line) with 32.16% inhibition at 50 µg/ml concentration. surprisingly, even though it has mmpl3 inhibitor characteristics, molecular modeling suggests that it is a hisg inhibitor. currently, there are no reported studies assessing efficacy of 12 against ntm [72] . considering the potency of other benzothiazoles, 10 and 11, 12 should be screened against ntm species and assessed for mmpl3 inhibition. ex vivo studies against thp-1 cell macrophages suggest that the compound enters murine and human macrophages, and has potential to decrease intracellular bacterial replication. in vivo zebrafish infection models reveal that 13 significantly decreases the bacterial load in the treated group as compared to the untreated group. however, mab_4508 mutants show high level resistance to the piperdinol derivatives, decreasing the potency of 13 by 4-to 64-fold. this mmpl3 inhibition decreases tdm formation and ag mycolylation in the periplasm [74] . recently, the piperidinol class was explored which led to the identification of 14. the sar suggests the importance of two aromatic rings, ring a and ring b, on both sides of the piperidinol. the two substituents, -cf 3 and -cl, on ring a are essential for activity. removing or changing the position of one or both substituents will significantly decrease the activity. similarly, the substitution of the small ortho group on ring b is optimal for the activity. replacing the -ch 3 to -cl on ring b yields 14 with the same potency (mic 99 = 0.125 µg/ml), suggesting preference for a lipophilic group. similarly, orthoiodine or bromine-containing molecules have similar potency to that of 14, but replacement with a fluorine substituent shows an eight-fold decrease in activity. this supports the role of steric hindrance at the receptor site, with larger radii atoms being preferred over smaller radii atoms, suggesting a twisted bioactive conformation. molecular modeling of the piperidinol derivative reveals that the nitrogen of 13 interacts with the carboxylic group of d618 and the hydroxyl of 13 interacts with the hydroxyl of y219 through hydrogen bonding. ring b is required to interact with the phenyl ring of f262 and f622 through π-π stacking interactions [75] . in vitro cytotoxicity studies in a vero cell line show that 14 is safe, achieving selectivity indices (si) of 400, whereas 13 has a si of 200 against m. abscessus. a preclinical pharmacokinetic study was performed on balb/c mice with drug administered via intraperitoneal (ip) route. the highest dosage used in the study was 250 mg/kg, which resulted in a 0% survival rate after 48 h. however, for the 100 mg/kg and 50 mg/kg groups, the survival rates increased to 67% and 100% after 96 h, respectively. more pharmacokinetic parameters were assessed, such as clearance rate, volume of distribution, and elimination half-life, none of which differ significantly from the values obtained by low et al. the clearance rate and peripheral volume of distribution are 6.9 ml/min and 2.0 l, and the elimination half-life is about 3.2 h. compound 13 has poor oral bioavailability, calculated at less than 1% [59] . currently, there are ongoing research efforts to improve the metabolic stability and polarity of this class of compound [75] . recently [48] . chemically, 17 is a n-[2-(4-chlorophenyl)ethyl]-4-thiophen-2-yloxane-4-carboxamide. this class of compounds is thought to directly inhibit mmpl3 [76] . the ethyl phenyl side chain on the nh of amide is optimal for the activity, removal of ethyl linker drastically decreases activity against m. tb, except for 4-isopropylphenyl and 4-trifluoromethyl. replacing the para-chloro with other groups led to loss of activity [76] . in vitro studies show that 17 binds mmpl3 directly without disrupting the membrane potential. there is no cross-resistance observed with sq109, suggesting different binding interactions with mmpl3. compound 17 shows a bacteriostatic effect in macrophages and is safe up to 200 µm [76] . compound 17 has good kinetic solubility of more than 300 µm. however, it exhibits poor microsomal stability, with only 45% remaining after 30 min [48] . it is also reported that the replacement of the thiophene group is warranted as it is susceptible to in vivo metabolism [76] . this interesting class of compounds should be further explored, as it shows potent activity against rgm along with desirable physicochemical properties. although benzofuran derivatives are ineffective against m. tb [58] , they possess activity against m. abscessus drug susceptible strain cip 104536 with a mic of 0.5-1 µg/ml [62] . structurally, it resembles the indole-2-carboxamide pharmacophore, except with an oxygen instead of a nitrogen in the aromatic ring system. therefore, this class lacks a potential h-bond donor interaction with mmpl3 which would have been formed by the nh of the indole. as of now, three benzofuran derivatives have been studied against m. abscessus. the two potent compounds (18 and 19) contains the cyclooctyl group as the cycloaliphatic ring on the rhs (mic = 0.5 µg/ml). compound 18 contains 4,6-dimethylbenzofuran whereas 19 contains 5-chlorobenzofuran. the cyclooctyl group is optimal for the activity, as replacement with an adamantyl ring decreases the activity by two-fold, mic = 1 µg/ml [62] . currently, there are no cytotoxicity studies or pharmacokinetic data available for this class of compounds. alsayed et al. screened a mini-series of quinolones and quinoline derivatives and determined them to be mmpl3 inhibitors. two quinolone derivatives showed putative antimycobacterial activity against m. tb with mics below 10 µg/ml, whereas quinoline derivatives were ineffective. all the quinolone compounds contain mono-or di-substitution on the lhs and the cyclooctyl or 1-adamantyl ring on the rhs. compound 20 is a 5-bromo-quinolone linked with 1-adamantyl ring through an amide side chain (m.tb mic = 4 µg/ml). potency decreases by two-fold when the 5-bromo is changed to 7-bromo (m.tb mic = 8 µg/ml), and 5,7-disubstitution drops the potency by four-fold as compared with 20. similarly, 6 or 8 mono-substitution or other di-substitutions result in loss of activity. the activity is higher for the quinolones than its tautomer, 4-hydroxyquinoline, suggesting the importance of the nh in the ring system which may form a h-bond with the receptor. in addition, the carboxamide side-chain at the 2-position is essential for activity, as changing from quinoline-2-carboxamide to quinoline-4-carboxamide results in loss of activity. although 20 is potent among all other quinolones against m. tb it lacks activity against sgm m. avium and rgm m. abscessus (mic > 159 µm). it exhibits low toxicity against vero cells (ic 50 = 39.87 µm) and has a si value of 4. however, 20 was found to have poor pharmacokinetic parameters, including solubility of 0.007 mg/ml, caco-2 permeability of 186 × 10 −6 cm/s, and 98% plasma protein binding [60] . further optimization is required to obtain activity against ntm species. in contrast to previous findings that the quinolines are ineffective, dan molin and colleagues identified the quinoline derivative, 21, which was found to be active against m. tb having a mic 90 of 7.8-15.6 µm. however, activity against m. abscessus is minimal (mic 90 > 31.25 µm). the scaffold varies from other mmpl3 inhibitors and 20. the removal of the methoxy group results in complete loss of activity against m. abscessus. unfortunately, 21 is associated with high cytotoxicity in thp-1 (7.8125 µm) [69] . currently, there is no available data in vivo pharmacokinetics or on how 21 binds mmpl3. further optimization of the compound to reduce cytotoxicity and improve activity against ntm species is needed. naphthalene derivatives were designed and synthesized as bioisosteric replacements of indole derivatives and further expanded the quinoline and quinolone study. five naphthalene-2-carboxamide derivatives were synthesized and screened in this study. out of the five compounds synthesized, two unsubstituted naphthalenes (22 and 23) were found to have activity against m. tb. they are structurally similar to each other, except for the cycloaliphatic ring on the rhs. compound 22 contains a cyclooctyl group whereas 23 contains an adamantyl group. adding substitutions to the naphthalene ring system is detrimental for antimycobacterial activity. compounds 22 and 23 are active against drug-susceptible and mdr m. tb (mic = 2 µg/ml and 6.5-13 µm, respectively), and have a two-fold increased potency against xdr tb strains (3.27-3.55 µm). however, they lack activity against ntm species such as m. avium and m. abscessus (mic > 209 µm) [60] . a cytotoxicity study showed no toxicity against vero cell lines (>227 µm and >419 µm). the molecular docking study performed on the compounds reveals that there is one less h-bond interaction with the mmpl3 receptor as compared to indole-2-carboxamides, suggesting reduced binding affinity. this supports the importance of the nh hydrogen within the indole ring. despite the fact that naphthalene and quinoline derivatives both lacks the nh hydrogen; activity is high with the naphthalene derivatives. because of high lipophilicity of the naphthene ring, these compounds are likely to have poor pharmacokinetic properties. the solubilities of 22 and 23 are 0.002 and 0.007 mg/ml. furthermore, 22 and 23 have caco-2 permeabilities of 190 and 207 × 10 −6 cm/s and plasma protein binding of 95% and 97% [60] . recently, gajdár et al. reported the 1-hydroxynaphthalene-2-carboxanilides as potent antimycobacterial agents. the study was performed using cyclic voltammetry and activity was determined based on electrochemical potential. compounds 24 and 25 were found to be effective against m. marinum and m. kansasii with mics of 28.8 µm (24) and 28.4 µm (25), and were determined to have similar activity against m. tb. using spinach chloroplast, the study showed that these compounds inhibit photosynthetic electron transfer (pet). it is thought that these derivatives have a multi-target effect including atp synthase and cytochrome bc1 with the disruption of the energy state of the cell [77] . acetamides can be formed with the deletion of 3-carbon atom from the indole-2-carboxamide derivatives. like indole-2-carboxamides, acetamides contain two rings, the aromatic ring on the lhs and the cycloaliphatic on the rhs, linked together with an amide moiety. shetty et al. were the first to report acetamides as a new class of mmpl3 inhibitors. using a single-point m. bovis bcg screening assay, they identified 16 hits with mics below 50 µm. compound 26 was one of these hits, with an mic 50 to explore the sar of 26, ten acetamide analogs were synthesized using the hit as the main pharmacophore. of the ten acetamides, only four compounds showed an increase in activity (mic 50 = 3-7 µm), whereas the other six compounds showed a drastic decrease in activity (mic 50 = 10->100 µm). the lipophilic groups on the aromatic ring are essential for activity. replacing the 4-trifluoromethyl with polar moieties such as cyano or ester groups decreased the activity, while activity is retained or increased with 3,5-dichloro or 3-or 4-trifluoromethoxy. changing the 3-or 4-trifluoromethoxy to 2-trifluoromethoxy causes inactivity (mic 50 > 100 µm). cycloaliphatic rings such as cyclohexane or cycloheptane (27) showed highest potency against m. tb (mic 50 = 3 µm), suggesting preference for bulkier cycloaliphatic groups. replacement of 1-cyanocyclopentane with an aliphatic group such as 1-cyano-1-methyl-isopropyl causes only a slight decrease in activity (mic 50 = 10 µm) and replacement with 1-cyano-1-methyl-cyclopropyl results in similar activity to that of the 26 (mic 50 = 7 µm) [49] . no further sar was performed to determine the importance of the 1-cyano group on the cycloaliphatic group. this scaffold is interesting for further sar development to determine if the activity is correlated to quaternary carbon or cycloaliphatic groups. cytotoxicity studies on 26 were performed on hepg2 (human liver carcinoma), thp-1 (human monocytic leukemia), and vero (african green monkey kidney epithelia) cell lines. results of these studies support low cytotoxicity and si of >25 µm. using rat liver microsomes, the half-life of the compound was found to be 28.6 min and the intrinsic clearance rate was 80.7 µl/min/mg of protein. as 26 lacks or possesses less activity as compared to the indole-2-carboxamides, further optimization and screening against ntm species is warranted [49] . previous screens show that the 1-substituted cyclooctyl ring has the highest potency against m. abscessus. we anticipate 27 to potentially display activity against m. abscessus. bm212 (28) is a commonly known as 1,5-diphenyl pyrrole derivative. compound 28 has shown activity against replicating and non-replicating m. tb including mdr-tb strains (mic = 8 µm). interestingly, the activity of 28 is greater against nontuberculous mycobacteria (mic m.avium = 1 µm) than m. tb (mic = 5 µm). compound 28 shows moderate cytotoxicity in vero cell lines (ic 50 = 9.6 µm) and has a si value of 1.92. a series of compounds (>300) was generated to improve the potency and physicochemical properties and reduce the cytotoxicity including herg inhibition. inhibition of the herg channel is responsible for the cardiotoxicity which was also associated with the spiro analog ( figure 3 ). despite good in vivo activity, the pyrrole derivatives suffer from poor solubility and metabolic profile, high plasma binding, and high herg channel inhibition. the proposed reason is the highly sp 2 region and easily protonated nitrogen in the structure. a hit-to-lead approach led to the discovery of 29 with improved in vitro and in vivo activity along with good physicochemical properties. the early sar suggests that the para-fluorophenyl at the n1 increases potency and reduces toxicity compared to 28. to maintain activity, lipophilic groups such as fluoro or electron donating groups such methoxyl or methylsulfanyl are required on the c5 position of the phenyl ring. the (thiomorpholin-4-yl) methyl ring has higher activity than the n-methylpyperazinyl group, later replaced with the morpholine group because of the metabolic instability. adding n-methylpiperazino-methyl or (thiomorpholin-4-yl) methyl group at the c4 position was found to be detrimental to activity. the para-isopropyl phenyl at c5 showed the highest microsomal stability in the mouse model. the sar was further studied by removing or replacing n1-and c5-phenyl with alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 µm and intramacrophagic mic of 0.16 µm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 µm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 µm. however, optimization is required to reduce the cytotoxic herg inhibition (16 µm) . moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 μm and intramacrophagic mic of 0.16 μm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 μm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 μm. however, optimization is required to reduce the cytotoxic herg inhibition (16 μm) . moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. m. abscessus = 0.063 µg/ml alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 μm and intramacrophagic mic of 0.16 μm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 μm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 μm. however, optimization is required to reduce the cytotoxic herg inhibition (16 μm) . moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 μm and intramacrophagic mic of 0.16 μm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 μm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 μm. however, optimization is required to reduce the cytotoxic herg inhibition (16 μm). moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 μm and intramacrophagic mic of 0.16 μm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 μm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 μm. however, optimization is required to reduce the cytotoxic herg inhibition (16 μm). moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. alkyl or cycloalkyl in order to decrease the sp 2 character. surprisingly, alkyl substituents at the n1 position retain antimycobacterial action. therefore, new sar indicates only one phenyl ring at c5 is essential for the activity whereas the n1 phenyl can be replaced with an alkyl or cycloalkyl substituent. the morpholine group is optimal for activity at the c3 position [78, 79] . compound 29 has an isopropyl group at the n1 position and para-isopropylphenyl group at the c5 position along with c2-methyl and c3-methyl morpholine. the compound has a mic value of 0.15 μm and intramacrophagic mic of 0.16 μm against m. tb. the cytotoxicity study on hepg2 gave to × 50 of 20 μm with a si of 133. the studied pharmacokinetic properties include membrane permeability of 7.2 × 10 −5 cm/s, 94.11% hsa binding, and clnd solubility of 199 μm. however, optimization is required to reduce the cytotoxic herg inhibition (16 μm). moreover, in vivo study report poor absorption and low bioavailability (f = 1.2%). compound 29 has moderate systemic clearance value of 16.9 ml/min/kg and a half-life of 1.7 h. at a dose of 50 mg/kg, 29 shows 1.5 log cfu reduction after 9 days of infection [79] . many pyrrole derivatives from the series have submicromolar activity against m. tb. ultimately, only 28 has shown potent activity against m. avium. given the medical need, the screening of pyrrole derivatives against mac and other ntm species is needed. 10 m. abscessus = 1 µ g/ml [70] m. avium = 2 µ g/ml m. abscessus = 0.03 µ g/ml [70] m. peregrinum = 0.03 µ g/ml m. massiliense = 0.03 µ g/ml m. fortuitum = 0.03 µ g/ml m. chelonae = 0.03 µ g/ml m. avium = 2 µ g/ml m. intracellulare = 2 µ g/ml n.d. [ 10 m. abscessus = 1 µ g/ml [70] m. avium = 2 µ g/ml m. abscessus = 0.03 µ g/ml [70] m. peregrinum = 0.03 µ g/ml m. massiliense = 0.03 µ g/ml m. fortuitum = 0.03 µ g/ml m. chelonae = 0.03 µ g/ml m. avium = 2 µ g/ml m. intracellulare = 2 µ g/ml n.d. [ an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with n.d. [79, 80] an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has been observed in resistant strains of mac [82, 83] . combining antibiotics should be done cautiously, as some combinations result in synergistic activity and suppression of antimycobacterial resistance, whereas other combinations exhibit deleterious drug-drug interaction. in vitro synergistic action is observed with amikacin or clarithromycin when administered with clofazimine, and here, it also prevents the re-growth of m. abscessus and m. avium [84] . similarly, in vitro studies report an increase in the action of clarithromycin against m. avium when combined with tigecycline. moreover, the combination therapy with tigecycline inhibits development of clarithromycin resistance [85] . synergistic action against m. abscessus is seen when either clarithromycin or tigecycline is co-administered with rifabutin [86] . rifabutin is also known to inhibit the inducible resistance of clarithromycin in m. abscessus [87] . conversely, in vitro negative drug-drug interaction is observed with the combination of bedaquiline and beta-lactams such as imipenem and cefoxitin [88] . in addition, there are few agents such as fs-1, smart-420, and c10 that promote reversion of drug resistance and restore the sensitivity of antibiotics. fs-1 is an anti-mdr/xdr tb drug, approved in 2015 in kazakhstan [89] . fs-1 consists of synthesized polysaccharide micellar units containing triiodide complexes coordinated by metal ions and integrated into a dextrin-polypeptide moiety resulting in a 30-300 kda complex [89] . the polysaccharides act as solubilizing agents and aid in the release of free iodine when mixed with water [90] . the released free iodine causes oxidative stress in the bacterial cell, a mechanism that drug-resistant mutants are more susceptible to [89, 91] . fs-1 induces reversion of drug resistance in mdr-and xdr-tb isolates by making them more susceptible to the oxidative stress induced by fs-1. fs-1 creates high oxidative stress inside the bacterial cell and resistance mutations are more sensitive to the oxidative stress. this led to the reduction in the drug resistance mutations. the reversion of drug resistance to aminoglycosides such as amikacin, kanamycin, and capreomycin has been observed in mdr-tb strains. adding fs-1 to the multi-drug regimen of tb prevents the accumulation of new drug resistance mutations and reduces the initial level of drug resistance in mdr-tb infections, and can reduce the duration of mdr-tb treatment from 24 months to 6-12 months [91] . the mic against the xrd-tb m. tb strain scaid 187.0 is decreased from 27.7 ± 2.4 µg/ml to 21.1 ± 2.0 µg/ml after the administration of fs-1 for 60 days. surprisingly, available data suggest that clinical xdr-tb isolates are more sensitive than the drug sensitive m. tb h37rv. in vitro studies of fs-1 against xdr-tb strain report >2-fold decrease in the mics for rifampicin, ethionamide, and pyrazinamide, followed by a small mic decrease for streptomycin and no change in mic for isoniazid. like in vitro, in vivo studies using hartley guinea pigs showed increases in susceptibility to antibiotics against m. tb isolates after treatment for 45 days. fs-1 induces dose-dependent drug resistance reversion with no direct interactions between fs-1 and the antibiotics. fs-1 also prevents recurrence of infection, which is commonly observed with antibiotics within 30 days of recovery time [89] . studies in human lymphocytes and tumor cell lines (hela and caco2) show no dna damaging action [90] . moreover, it has been observed in animal models that fs-1 reduces the hepatotoxicity caused by some antimycobacterial agents [89] . biotransformation of the antibiotics causes rapid inactivation of antibiotics via enzymes such as beta-lactamases. on the other hand, biotransformation is also required for pro-antibiotics (prodrug antibiotics) for activation. mutations in the bioactivating enzymes makes the drug ineffective. for example, mutations in katg, pnca, and etha is observed in isoniazid (inh), pyrazinamide (pza), and ethionamide (eth)-resistant clinical isolates, respectively [92] . blondiaux et al. report small molecules aborting resistance (smart-420), a spiroisoxazoline compound, which restores the sensitivity of all eth-resistant, mdr-and xdr-tb clinical isolates (figure 4 ). smart-420 provides an alternative bioactivation pathway to eth, but does not elicit any antibacterial action. although ineffective in the absence of eth, smart-420 boosts the activity of eth against eth-sensitive and -resistant m. tb. in vivo efficacy studies in a murine model confirm that eth alone is ineffective against eth-resistant strains, whereas the combination of eth with smart-420 significantly reduces the bacterial load (4.6 log) in mouse lungs in a dose-dependent manner. the study proposed that smart-420 triggers cryptic drug-bioactivation pathways in drug-resistant pathogens [92] . these examples provide insight that drug resistance is not irrevocable and discovery of small molecules could reverse it. further studies to investigate additional compounds that reverse drug resistance and evaluate use of such agents in combination with antibiotics against drug-resistant ntm strains are warranted. the current treatment for the ntm infection includes three antibiotics for at least for 18 months or 12 months after the first negative culture. the regimen includes a combination of approved tb drugs, macrolides, and aminoglycosides. however, treatment outcomes are often poor, the medications used are associated with serious adverse reactions, and there is a high chance of relapse or reinfection to the cured patient. in addition, ntm species are rapidly acquiring resistance to currently available antibiotic options, with resistance being observed even in recently approved drugs [69] . the liposomal amikacin inhalation suspension was recently approved for the treatment of m. avium infections. however, the resistance to the amikacin causes drop in the potency by more than two-fold [82] . therefore, new drugs with novel mechanisms are urgently needed. recently, many compounds have been developed that show activity against tb and ntm infections that target the mmpl3. as mmpl3 inhibitors act at the level of the plasma membrane, it is possible that some if not all of them can avoid biotransformation by cytoplasmic enzymes. mmpl3 is an attractive and promiscuous target for tb drugs that plays an important role in cell envelope biosynthesis. tmm, the mycolic acid donor, is synthesized within the bacterial cell and translocated into the periplasm via a mechanism involving the mmpl3 transporter. mmpl3 utilizes the proton motive force to facilitate this translocation. inhibition of mmpl3 transporter increases tmm levels inside the cell and decreases mycolic acids in the periplasm, thus exerting a bactericidal effect. as mycolic acid biosynthesis is required for the viability in all mycobacteria, mmpl3 inhibitors are effective against both m. tb and ntm species. all inhibitors whose interaction with mmpl3 has been characterized to date appear to inhibit mmpl3 directly although some of them display additional disrupting activity on the pmf that may further potentiate their activity against the transporter and confer upon them activity against non-replicating bacilli [50] . the classes of mmpl3 inhibitors explored against ntm species are indoles, benzimidazoles, benzothiazoles, quinolines and quinolones, benzofurans, thiophenes, naphthalenes, acetamides, and piperidines. as per table 1 , indole-2-carboxamides (1, 2, 3, 4) , benzimidazole (6), benzothiazole (12), c10 inhibits m. tb pellicle formation (mic = 6.25 µm) and blocks hypoxia-induced tolerance to oxidative stress, acid stress, and isoniazid (inh) (figure 4 ). resistance against inh, a prodrug activated by katg enzymes, typically emerges as a result of mutations in katg. c10 has been found to reverse resistance to inh in m. tb katg mutants. c10 does not have activity over other antibiotics such as ethambutol, rifampicin, or streptomycin. moreover, c10 acts synergistically with q203, an etc inhibitor targeting cytochrome bc 1 which is undergoing clinical trials [93] . these examples provide insight that drug resistance is not irrevocable and discovery of small molecules could reverse it. further studies to investigate additional compounds that reverse drug resistance and evaluate use of such agents in combination with antibiotics against drug-resistant ntm strains are warranted. the current treatment for the ntm infection includes three antibiotics for at least for 18 months or 12 months after the first negative culture. the regimen includes a combination of approved tb drugs, macrolides, and aminoglycosides. however, treatment outcomes are often poor, the medications used are associated with serious adverse reactions, and there is a high chance of relapse or reinfection to the cured patient. in addition, ntm species are rapidly acquiring resistance to currently available antibiotic options, with resistance being observed even in recently approved drugs [69] . the liposomal amikacin inhalation suspension was recently approved for the treatment of m. avium infections. however, the resistance to the amikacin causes drop in the potency by more than two-fold [82] . therefore, new drugs with novel mechanisms are urgently needed. recently, many compounds have been developed that show activity against tb and ntm infections that target the mmpl3. as mmpl3 inhibitors act at the level of the plasma membrane, it is possible that some if not all of them can avoid biotransformation by cytoplasmic enzymes. mmpl3 is an attractive and promiscuous target for tb drugs that plays an important role in cell envelope biosynthesis. tmm, the mycolic acid donor, is synthesized within the bacterial cell and translocated into the periplasm via a mechanism involving the mmpl3 transporter. mmpl3 utilizes the proton motive force to facilitate this translocation. inhibition of mmpl3 transporter increases tmm levels inside the cell and decreases mycolic acids in the periplasm, thus exerting a bactericidal effect. as mycolic acid biosynthesis is required for the viability in all mycobacteria, mmpl3 inhibitors are effective against both m. tb and ntm species. all inhibitors whose interaction with mmpl3 has been characterized to date appear to inhibit mmpl3 directly although some of them display additional disrupting activity on the pmf that may further potentiate their activity against the transporter and confer upon them activity against non-replicating bacilli [50] . the classes of mmpl3 inhibitors explored against ntm species are indoles, benzimidazoles, benzothiazoles, quinolines and quinolones, benzofurans, thiophenes, naphthalenes, acetamides, and piperidines. as per table 1 , indole-2-carboxamides (1, 2, 3, 4) , benzimidazole (6), benzothiazole (12) , piperidinol (13, 14) , benzofuran (18, 19) show sub micromolar activity against m. abscessus. compounds 1, 5, and 12 must be explored further to determine the activity against m. avium. therefore, in vivo testing should be conducted on these scaffolds to further screen against other ntm species. indole-2-carboxamides are extensively explored via in vitro and in vivo studies and show promising results. however, poor physiochemical and pharmacokinetic properties remain a barrier to drug development. the challenge that most mmpl3 inhibitors face is low solubility due to high lipophilicity. compounds 7 and 17 show a good solubility with moderate activity, but 7 has high metabolic stability, in contrast to 17. other emerging novel targets such as pks13 or fadd32, enzymes involved in the mycolic acid biosynthesis, have proven effective against m. tb. however, not many compounds have been screened against ntm species. classes of pks13 inhibitors include thiophenes, benzofurans, beta-lactams, and coumestans [94] . despite thiophene (tp2) derivatives having high potency against lab and clinical strains of m. tb with mic = 1 µm , they are inactive against sgm and rgm (mic > 128 µm) [95] . similarly, pks13 inhibitors identified as hits have mic <1 µm against m. tb but >31.25 µm against m. abscessus [69] , which may explain the lack of screening attempts against other ntm species. conversely, diarylcoumarins, a class of fadd32 inhibitors, have potent action against sgm (mic of 0.83 µm and 2.4 µm against m. marinum and m. intracellulare, respectively) [96] . recently, a new class of fadd32 inhibitor, the quinolines, were reported to maintain potent antimycobacterial activity while displaying improved pharmacokinetic properties [97] . however, screening of these compounds against the ntm species has not yet been reported. in addition, fs-1 and smart-420 could be potential agents to reverse the susceptibility of the drug-resistant ntm species. both compounds show reversion of drug resistance in the mdr-tb and xdr-tb when co-administered with tb antibiotics. fs-1 significantly decreases mics of rifampicin, ethionamide, and pyrazinamide. moreover, fs-1 also alleviates the hepatoxicity caused by antibiotics. smart-420 alters etha-dependent drug-bioactivation pathways restoring susceptibility in eth-resistant pathogens. there is an urgent need for developing a drug discovery pipeline against ntm infections. the in vitro assays must include sgm and rgm species along with m. tb as part of the screening. available data suggest that tb inactive compounds may retain activity against ntm species, encouraging a broader perspective on potential candidates for treating ntm infections. in testing ntm species, different morphotypes should be assessed because of the potential for varied susceptibility to antimicrobials [26, 98] . in conclusion, mmpl3 inhibitors have potent activity against sgm and rgm. studies also report synergistic action of mmpl3 inhibitors with tb antibiotics in vitro and in vivo [99, 100] . as treatment of ntm infections involves multidrug regimens, adding an mmpl3 inhibitor to the current therapeutic regimen may be beneficial. therefore, more research is required to explore mmpl3 inhibitors against ntm species and to develop a constant pipeline of drug candidates for treatment of ntm infections. nontuberculous mycobacteria (ntm) infections |hai| cdc. available online non-tuberculous mycobacteria and the rise of mycobacterium abscessus the new phylogeny of the 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membrane transporter of trehalose monomycolate involved in mycolic acid donation to the cell wall core of mycobacterium tuberculosis new approaches to target the mycolic acid biosynthesis pathway for the development of tuberculosis therapeutics mmpl3 is a lipid transporter that binds trehalose monomycolate and phosphatidylethanolamine mmpl3 is the flippase for mycolic acids in mycobacteria crystal structures of membrane transporter mmpl3, an anti-tb drug target structure-function profile of mmpl3, the essential mycolic acid transporter from mycobacterium tuberculosis the mmpl3 interactome reveals a complex crosstalk between cell envelope biosynthesis and cell elongation and division in mycobacteria essentiality of mmpl3 and impact of its silencing on mycobacterium tuberculosis gene expression therapeutic potential of the mycobacterium tuberculosis mycolic acid transporter, mmpl3 a piperidinol-containing molecule is active against mycobacterium tuberculosis by inhibiting the mycolic 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novel pyrazole-containing compounds active against mycobacterium tuberculosis chapter three-development of mmpl3 inhibitors for tuberculosis treatment medicinal chemistry approaches to tuberculosis and trypanosomiasis improved bm212 mmpl3 inhibitor analogue shows efficacy in acute murine model of tuberculosis infection amikacin liposome inhalation suspension for mycobacterium avium complex lung disease. sr. care pharm antimycobacterial susceptibility testing of nontuberculous mycobacteria identification and drug susceptibility testing for nontuberculous mycobacteria clofazimine prevents the regrowth of mycobacterium abscessus and mycobacterium avium type strains exposed to amikacin and clarithromycin tigecycline potentiates clarithromycin activity against mycobacterium avium in vitro rifabutin acts in synergy and is bactericidal with frontline mycobacterium abscessus antibiotics clarithromycin and tigecycline, suggesting a potent treatment combination rifabutin suppresses inducible clarithromycin resistance in mycobacterium abscessus by blocking induction of whib7 and erm41 bedaquiline eliminates bactericidal activity of β-lactams against mycobacterium abscessus genomic insight into mechanisms of reversion of antibiotic resistance in multidrug resistant mycobacterium tuberculosis induced by a nanomolecular iodine-containing complex fs-1 investigations of genotoxic activity of antimicrobial/antiviral agent fs-1 in human lymphocytes and tumor cell constraints of drug resistance in-prospects for pharmacological reversion of susceptibility to antibiotics reversion of antibiotic resistance in mycobacterium tuberculosis by spiroisoxazoline smart-420 chemical disarming of isoniazid resistance in mycobacterium tuberculosis identification of novel coumestan derivatives as polyketide synthase 13 inhibitors against mycobacterium tuberculosis. part ii antituberculosis thiophenes define a requirement for pks13 in mycolic acid biosynthesis diarylcoumarins inhibit mycolic acid biosynthesis and kill mycobacterium tuberculosis by targeting fadd32. proc. natl. acad. sci discovery of heterocyclic replacements for the coumarin core of anti-tubercular fadd32 inhibitors mycobacterium abscessus, an emerging and worrisome pathogen among cystic fibrosis patients synergistic interactions of mmpl3 inhibitors with antitubercular compounds in vitro indole-2-carboxamide-based mmpl3 inhibitors show exceptional antitubercular activity in an animal model of tuberculosis infection this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license n.d. [49] 28 m. avium = 2 µ m [79, 80] 29 n.d. [79, 80] an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has been observed in resistant strains of mac [82, 83] . combining antibiotics should be done cautiously, as some combinations result in synergistic activity and suppression of antimycobacterial resistance, an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has been observed in resistant strains of mac [82, 83] . combining antibiotics should be done cautiously, an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has been observed in resistant strains of mac [82, 83] . combining antibiotics should be done cautiously, an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with nephrotoxicity being the most serious [81] . in addition, greater than a two-fold drop in potency has n.d.[49] an inhaled liposomal amikacin inhalation suspension (arikacye ® ) has recently been approved by the fda for the treatment of mac infections of the lung in adults with limited or no alternative treatment options. this formulation is part of a combination regimen in patients who fail to achieve negative sputum cultures after a minimum of six consecutive months of first-line multidrug antibiotic therapy. the treatment is associated with many adverse effects, with funding: this project was supported by the national institutes of health/national institute of allergy and infectious diseases research grant ai116525 and an award from the cystic fibrosis foundation. the authors declare no conflict of interest. key: cord-340879-gu91cact authors: li, miao; liu, qin; cui, yajuan; li, dong; wang, hexiang; ng, tzi bun title: isolation and characterization of a phaseolus vulgaris trypsin inhibitor with antiproliferative activity on leukemia and lymphoma cells date: 2017-01-23 journal: molecules doi: 10.3390/molecules22010187 sha: doc_id: 340879 cord_uid: gu91cact a 17.5-kda trypsin inhibitor was purified from phaseolus vulgaris cv. “gold bean” with an isolation protocol including ion exchange chromatography on deae-cellulose (diethylaminoethyl-cellulose), affinity chromatography on affi-gel blue gel, ion exchange chromatography on sp-sepharose (sulfopropyl-sepharose), and gel filtration by fplc (fast protein liquid chromatography) on superdex 75. it dose-dependently inhibited trypsin with an ic(50) value of 0.4 μm, and this activity was reduced in the presence of dithiothreitol in a doseand time-dependent manner, signifying the importance of the disulfide linkage to the activity. it inhibited [methyl-(3)h] thymidine incorporation by leukemia l1210 cells and lymphoma mbl2 cells with an ic(50) value of 2.3 μm and 2.5 μm, respectively. the inhibitor had no effect on fungal growth and the activities of various viral enzymes when tested up to 100 μm. protease inhibitors have been isolated from the seeds of different monocots and dicots, including maize [1] , wheat [2] , wampee [3] , bitter gourd [4] , momordica cochinchinensis [5] , and legumes [6] [7] [8] . some of them display a variety of biological activities including antifungal [9] , immunomodulatory [5] and antitumor/antiproliferative [8, 10] activities. thus, they have drawn the attention of many researchers. one class of protease inhibitors is trypsin inhibitors. trypsin inhibitors are divided into kunitz type [11] , bowman-birk type [12, 13] , and squash type [4] . the three types have a molecular mass of about 20 kda, 8 kda, and 3 kda, respectively. the soybean produces both kunitz and bowman-birk inhibitors [6] , while melons belonging to family cucurbitaceal produce squash-type inhibitors [4] . leguminous seeds are a rich source of proteins, including protease inhibitors, lectins [14] , antifungal proteins [15] , ribosome inactivating proteins [16] , and arcelins [17] . some of the proteins have interesting biological activities, such as insecticidal [14] , immunomodulatory [5] , antifungal [18] , and antitumor [8, 10] activities. the intent of the present study was to isolate a trypsin inhibitor from the gold bean and to test it for inhibitory action on tumor cells, viral enzymes, and fungal growth. upon ion exchange chromatography on deae-cellulose, the bean extract was separated into three fractions of approximately equal size, an unadsorbed fraction d1 and two adsorbed fractions d2 and d3. trypsin inhibitory activity was located in fraction d2. when fraction d2 was subjected to affinity chromatography on affi-gel blue gel, the activity was recovered in the larger unadsorbed fraction b1 (data not shown). upon ion exchange chromatography on sp-sepharose, fraction b1 was resolved into a small unadsorbed fraction s1 and two large adsorbed fractions (s2 and s3) of approximately equal size. activity resided in fraction s2. further purification of s2 on superdex 75 yielded two fractions, su1 and su2. only fraction su2 exhibited trypsin inhibitory activity. su2 was the purified trypsin inhibitor (gbti). the yields of the various chromatographic fractions are presented in table 1 . the n-terminal sequence of the trypsin inhibitor is shown in table 2 . gbti exhibited a molecular mass of 17.5 kda in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and gel filtration ( figure 1 ). its trypsin inhibitor activity remained unchanged in the temperature range 20-80 • c, was reduced by 60% at 90 • c, and, was totally abolished after exposure to 100 • c. upon ion exchange chromatography on deae-cellulose, the bean extract was separated into three fractions of approximately equal size, an unadsorbed fraction d1 and two adsorbed fractions d2 and d3. trypsin inhibitory activity was located in fraction d2. when fraction d2 was subjected to affinity chromatography on affi-gel blue gel, the activity was recovered in the larger unadsorbed fraction b1 (data not shown). upon ion exchange chromatography on sp-sepharose, fraction b1 was resolved into a small unadsorbed fraction s1 and two large adsorbed fractions (s2 and s3) of approximately equal size. activity resided in fraction s2. further purification of s2 on superdex 75 yielded two fractions, su1 and su2. only fraction su2 exhibited trypsin inhibitory activity. su2 was the purified trypsin inhibitor (gbti). the yields of the various chromatographic fractions are presented in table 1 . the n-terminal sequence of the trypsin inhibitor is shown in table 2 . gbti exhibited a molecular mass of 17.5 kda in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and gel filtration ( figure 1 ). its trypsin inhibitor activity remained unchanged in the temperature range 20-80 °c, was reduced by 60% at 90 °c, and, was totally abolished after exposure to 100 °c. trypsin inhibitor-enriched fractions are highlighted in boldface. results represent mean ± sd, n = 2. trypsin inhibitor-enriched fractions are highlighted in boldface. results represent mean ± sd, n = 2. gbti inhibited trypsin with an ic 50 of 0.4 µm ( figure 2 ). dithiothreitol (dtt) treatment lowered the trypsin inhibitory activity in a dose-and time-dependent manner ( table 3 ). the ic 50 values of the inhibitory effects of gbti on l1210 cells and mbl2 cells were 2.3 µm and 2.5 µm, respectively (table 4) . there was no inhibition on hiv-1 reverse transcriptase when it was tested at various concentrations up to 100 µm ( table 5 ). the inhibitor had no effect on the activities of hiv-1 integrase (table 5 ) and sars coronavirus proteinase at 100 µm. there was no inhibitory action on fungal growth at 100 µm (table 6) . table 3 . inhibition rate (%) of dithiothreitol (dtt) on the activity of gbti and soybean trypsin inhibitor after incubation at 37 • c for different durations. results are presented as mean ± sd (n = 3). different letters (e.g., a,b and c ) indicate statistically significant differences (p < 0.05) when (i) data at the same time point and different dtt concentrations or (ii) data at the same dtt concentration, but different time points, were analyzed by analysis of variance followed by duncan's multiple range test. inhibition rate (%) of purified or soybean trypsin inhibitor at x mm dtt = (trypsin inhibitory activity of purified or soybean trypsin inhibitor−trypsin inhibitory activity of purified or soybean trypsin inhibitor in presence of x mm dtt)/trypsin inhibitory activity of purified or soybean trypsin inhibitor × 100%. results are presented as mean ± sd (n = 3). different letters (e.g., a,b,c and d ) indicate statistically-significant differences (p < 0.05) when data were analyzed by analysis of variance followed by duncan's multiple range test. gold bean trypsin inhibitor (gbti) is unadsorbed on affi-gel blue gel, but adsorbed on deae-cellulose. this chromatographic behavior is distinctly different from that of other leguminous antifungal proteins which are unadsorbed on the ion exchanger and adsorbed on the affinity chromatography media [15, 19] . hence, the purification procedure described herein provides a convenient means to separate trypsin inhibitors from antifungal proteins which may be present in the same legume. the trypsin inhibitor from gold beans demonstrate some sequence resemblance to other leguminous trypsin inhibitors including those of cowpea, mung bean, and garden pea. it is noteworthy that it exerts a potent antiproliferative action on both l1210 cells and mbl2 cells. some of the legume trypsin inhibitors, for instance, field bean trypsin inhibitors, inhibit in vitro proliferation of cancer cells and metastasis in vivo [20, 21] . gold bean trypsin inhibitor is dissimilar from broad bean trypsin inhibitor [9] in that the former lacks hiv-1 reverse transcriptase inhibitory activity. the lack of hiv-1 reverse transcriptase inhibitory activity in gold bean trypsin inhibitor is similar to the findings on lily bulb trypsin inhibitor [22] . gold bean trypsin inhibitor is also devoid of any inhibitory effect on hiv-1 integrase and sars coronavirus proteinase. the absence of antifungal activity in gold bean trypsin inhibitor is also in agreement with the observation on some trypsin inhibitors, such as lily bulb trypsin inhibitor [22] . the results demonstrate that hiv-1 reverse transcriptase inhibitory and antifungal activities of trypsin inhibitors have structural requirements different from those of trypsin inhibitory activity. the importance of the disulfide linkage in gold bean trypsin inhibitor to its trypsin inhibitory activity is revealed by the ability of the reducing agent dithiothreitol to reduce the activity. this is reminiscent of the results on trypsin-chymotrypsin inhibitor from vigna mungo seeds [23] . gold bean trypsin inhibitor (gbti) is unadsorbed on affi-gel blue gel, but adsorbed on deae-cellulose. this chromatographic behavior is distinctly different from that of other leguminous antifungal proteins which are unadsorbed on the ion exchanger and adsorbed on the affinity chromatography media [15, 19] . hence, the purification procedure described herein provides a convenient means to separate trypsin inhibitors from antifungal proteins which may be present in the same legume. the trypsin inhibitor from gold beans demonstrate some sequence resemblance to other leguminous trypsin inhibitors including those of cowpea, mung bean, and garden pea. it is noteworthy that it exerts a potent antiproliferative action on both l1210 cells and mbl2 cells. some of the legume trypsin inhibitors, for instance, field bean trypsin inhibitors, inhibit in vitro proliferation of cancer cells and metastasis in vivo [20, 21] . gold bean trypsin inhibitor is dissimilar from broad bean trypsin inhibitor [9] in that the former lacks hiv-1 reverse transcriptase inhibitory activity. the lack of hiv-1 reverse transcriptase inhibitory activity in gold bean trypsin inhibitor is similar to the findings on lily bulb trypsin inhibitor [22] . gold bean trypsin inhibitor is also devoid of any inhibitory effect on hiv-1 integrase and sars coronavirus proteinase. the absence of antifungal activity in gold bean trypsin inhibitor is also in agreement with the observation on some trypsin inhibitors, such as lily bulb trypsin inhibitor [22] . the results demonstrate that hiv-1 reverse transcriptase inhibitory and antifungal activities of trypsin inhibitors have structural requirements different from those of trypsin inhibitory activity. the importance of the disulfide linkage in gold bean trypsin inhibitor to its trypsin inhibitory activity is revealed by the ability of the reducing agent dithiothreitol to reduce the activity. this is reminiscent of the results on trypsin-chymotrypsin inhibitor from vigna mungo seeds [23] . a lectin, an antifungal protein and a trypsin inhibitor can be isolated from the gold bean [24, 25] . all three proteins can be regarded as defense proteins that protect the plant from pathogenic and predatory organisms. previously, a trypsin inhibitors have been isolated from phaseolus vulgaris. however, they have not been examined for biological activities other than trypsin inhibitory activity [26] [27] [28] [29] [30] [31] [32] . in conclusion, a new trypsin inhibitor was purified from gold bean. it dose-dependently inhibited trypsin, and this activity was reduced in the presence of dithiothreitol in a dose-and time-dependent manner, signifying the importance of the disulfide linkage to the activity. it inhibited [methyl-3h] thymidine incorporation by leukemia l1210 cells and lymphoma mbl2 cells. a water extract of gold beans phaseolus vulgaris cv. "gold bean" from mainland china (260 g) was made by homogenizing them in distilled water (6 ml/g). the homogenate was then centrifuged 4) . the unadsorbed proteins (fraction b1) were dialyzed against 10 mm nh 4 ac buffer (ph 5) and applied on a 2.5 × 20 cm column of sp-sepharose (ge healthcare, uppsala, sweden). after elution of unadsorbed proteins (fraction s1), the column was eluted with a 0-1 m nacl concentration gradient in the nh 4 ac buffer. the first adsorbed fraction (s2) was then subjected to gel filtration on a superdex 75 hr 10/30 column (ge healthcare) in 0.2 m nh 4 hco 3 buffer (ph 8.5). the second absorbance peak (su2) represented purified trypsin inhibitor (gbti). the assay for trypsin inhibitory activity was carried out by addition of test sample (20 µl) to 160 µl of a 1% casein solution in 0.1 m tris-hcl buffer (ph 7.4). trypsin (20 µl of a 0.5 mg/ml solution) was then added and the mixture was incubated at 37 • c for 15 min before 0.4 ml 5% trichloroacetic acid was added to terminate the reaction. after centrifugation, the absorbance of the supernatant, which reflects the amount of casein fragments, was measured at 280 nm [22] . the purified trypsin inhibitor was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page, woodinville, wa, usa) for molecular mass determination in accordance with the procedure of laemmli and favre [33] . gel filtration on an fplc-superdex 75 column (ge healthcare, uppsala, sweden), which had been calibrated with molecular mass markers including phosphorylase b (94 kda), bovine serum albumin (67 kda), ovalbumin (43 kda), carbonic anhydrase (30 kda), soybean trypsin inhibitor (20 kda) and α-lactalbumin (14.4 kda) (ge healthcare), was conducted to determine the molecular mass of the protein. the n-terminal sequence of the trypsin inhibitor was determined by using a hewlett-packard hp g1000a edman degradation unit (hewlett packard company, palo alto, ca, usa) and an hp 1000 hplc system (hewlett packard company, palo alto, ca, usa). the purified trypsin inhibitor was incubated in a water bath at different temperatures from 20 • c to 100 • c for 15 min, then immediately chilled on ice. the reaction mixture was then subjected to the assay of trypsin inhibitory activity. the purified trypsin inhibitor (2.5 µm) was incubated with dithiothreitol (dtt) at the final concentration of 2.5, 10, and 40 mm for 5, 20, and 80 min at 37 • c, respectively. for comparison, soybean trypsin inhibitor purchased from sigma chemical co., (st. louis, mi, usa) (2.5 µm) was similarly treated. the reaction was terminated by adding iodoacetamide at twice the amount of thiol functions at each dtt concentration. the remaining trypsin inhibitor activity was measured at ph 7.4, as described above. the highest iodoacetamide concentration used in the test was devoid of any effect on the activity of trypsin and the trypsin inhibitory activity of purified trypsin inhibitor and soybean trypsin inhibitor [34] . the antiproliferative activity of the purified protein was determined as follows. the cell lines l1210 (leukemia) and mbl2 (lymphoma) were purchased from american type culture collection. the cell line was maintained in dulbecco modified eagles' medium (dmem) supplemented with 10% fetal bovine serum (fbs) and 100 mg/l streptomycin and 100 iu/ml penicillin at 37 • c in a humidified atmosphere of 5% co 2 . cells (1 × 10 4 ) in their exponential growth phase were seeded into each well of a 96-well culture plate (nunc, roskilde, denmark) and incubated for 3 h before addition of the trypsin inhibitor. incubation was carried out for another 48 h. radioactive precursor, 1 µci ([ 3 h-methyl]-thymidine, from ge healthcare), was then added to each well and incubated for 6 hrs. the cultures were then harvested by a cell harvester. the incorporated radioactivity was determined by liquid scintillation counting [15] . the assay for hiv reverse transcriptase inhibitory activity was carried out in view of the report that trypsin inhibitors manifest this activity [35, 36] . it was conducted according to instructions supplied with the assay kit from boehringer mannheim (basel, switzerland). the assay takes advantage of the ability of reverse transcriptase to synthesize dna, starting from the template/primer hybrid poly (a) oligo (dt) 15. the digoxigenin-and biotin-labeled nucleotides in an optimized ratio are incorporated into one of the same dna molecule, which is freshly synthesized by the reverse transcriptase (rt). the detection and quantification of synthesized dna as a parameter for rt activity follows a sandwich elisa protocol. biotin-labeled dna binds to the surface of microtiter plate modules that have been pre-coated with strepatavidin. in the next step, an antibody to digoxigenin, conjugated to peroxidase enzyme, binds to the digoxigenin-labeled dna. in the final step, the peroxidase substrate is added. the peroxidase enzyme catalyzes the cleavage of the substrate, producing a colored reaction product. the absorbance of the sample at 405 nm can be determined using a microtiter plate (elisa) reader and is directly correlated to the level of rt activity. a fixed amount (4-6 ng) of recombinant hiv-1 reverse transcriptase was used. the inhibitory activity of the protein was calculated as percent inhibition compared to a control without the protein [15] . the positive control used was kale antifungal peptide. the plasmid that expressed his-tagged wild-type hiv-1 integrase, pt7-7-his (y|tx)-hiv-1-in, was a generous gift from professor s.a. chow (school of medicine, ucla). to express the protein, a 1-liter culture of e. coli bl21 (de3) cells containing the expression plasmid was grown at 37 • c until od600 reached 0.7-0.8. cells were induced by addition of 0.8 mm iptg (isopropyl-β-d-thiogalactopyranoside) and harvested, after 4 h of incubation, by centrifugation at 6000× g for 10 min at 4 • c cells were suspended at a concentration of 0.1 g/ml wet cell paste in 20 mm tris-hcl buffer (ph 8.0) containing 0.1 mm edta (ethylenediamine tetraacetic acid), 2 mm β-mercaptoethanol, 0.5 m nacl and 5 mm imidazole. lysozyme was added to a concentration of 0.2 mg/ml. after incubation at 4 • c for 1 h, the lysate was sonicated and centrifuged at 40,000× g at 4 • c for 20 min. the pellet was homogenized in 50 ml buffer a (20 mm tris-hcl, ph 8.0, 2 m nacl, 2 mm β-mercaptoethanol) containing 5 mm imidazole. the suspension was rotated at 4 • c for 1 h, and cleared by centrifugation at 40,000× g at 4 • c for 20 min. the supernatant was loaded onto a 1-ml chelating sepharose column (ge healthcare) charged with 50 mm niso 4 and was equilibrated with buffer a containing 50 mm imidazole. the column was washed with five column volumes of buffer a containing 5 mm imidazole, and the protein was eluted with three column volumes of buffer a containing 200 and 400 mm imidazole, respectively. protein containing fractions were pooled, and edta was added to a final concentration of 5 mm. the protein was dialyzed against buffer b (20 mm hepes, ph 7.5, 1 mm edta, 1 m nacl, 20% glycerol) containing 2 mm β-mercaptoethanol, and then against buffer b containing 1 mm dithiothreitol. aliquots of the protein were stored at −70 • c [19] . a non-radioactive elisa-based hiv-1 integrase assay was performed according to the dna-coated plate method. in this study, 1 µg of smal-linearized pbluescript sk was coated onto each well in the presence of 2 m nacl as target dna. the donor dna was prepared by annealing vu5br (5'-biotin-gtgtggaaaatctctagcagt-3') and vu5 (5'-actgctagagattttccacac-3') in 10 mm tris-hc1, ph 8.0, 1 mm edta and 0.1 m nacl at 80 • c, followed by 30 min at room temperature. integrase reaction was performed in 20 mm hepes (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) (ph 7.5) containing 10 mm mncl 2 , 30 mm nacl, 10 mm dithiothreitol and 0.05% nonidet-p40 (sigma). after the integrase reaction, the biotinylated dna immobilized on the wells was detected by incubation with streptavidin-conjugated alkaline phosphatase (boehringer-mannheim, mannheim, germany), followed by colorimetric detection with 1 mg/ml p-nitrophenyl phosphate in 10% diethanolamine buffer (ph 9.8) containing 0.5 mm mgcl 2 . the absorbance due to the alkaline phosphatase reaction was measured at 415 nm. the ribosome inactivating protein luffin was used as a positive control [16] . the activity of sars coronavirus (cov) protease was indicated by a cleavage of designed substrate which was composed of two proteins linked by a cleavage site for sars cov protease. the reaction was performed in a mixture containing 5 µm sars cov protease, 5 µm sample, 20 µm substrate, and buffer [20 mm tris-hcl (ph 7.5), 20 mm nacl and 10 mm beta-mercaptoethanol] for 40 min at 37 • c. after 40 min, the reaction was stopped by heating at 100 • c for 2 min. then the reaction mixture was analysed by sds-page. if sars cov protease is inhibited by the test sample, there is only one band, which is the intact substrate, shown in sds-page [19] . this assay was conducted in view of the report on antifungal activity of some trypsin inhibitors [9] . the assay for antifungal activity toward mycosphaerella arachidicola and fusarium oxysporum was carried out in 100 mm × 15 mm petri dishes containing 10 ml of potato dextrose agar. after the mycelial colony had developed, sterile blank paper disks (0.625 cm in diameter) were placed at a distance of 0.5 cm away from the rim of the mycelial colony. an aliquot (15 µl) of the purified trypsin inhibitor was added to a disk. the plates were incubated at 23 • c for 72 h until mycelial growth had enveloped the disks containing the control and had formed crescents of inhibition around the disks containing samples with antifungal activity [15] . the positive control used was kale antifungal peptide. a 17.5-kda trypsin inhibitor was purified from phaseolus vulgaris cv. "gold bean". it was adsorbed on deae-cellulose, unadsorbed on affi-gel blue gel, and adsorbed on sp-sepharose. it dose-dependently inhibited trypsin with an ic 50 value of 0.4 µm. about 80% and all of the trypsin inhibitory activity were abolished after treatment with 2.5 mm dithiothrietol for 5 min and 20 min of incubation, respectively. [methyl-3h] thymidine incorporation by leukemia l1210 cells and lymphoma mbl2 cells was inhibited with an ic 50 value of about 2 µm. mycelial growth in fusarium oxysporum and mycosphaerella arachidicola were unaffected. the activities of hiv-1 reverse transcriptase, hiv-1 integrase and sars coronavirus proteinase were unaltered after exposure to the trypsin inhibitor. amino acid sequence and secondary structural analysis of the corn inhibitor of trypsin and activated hageman factor primary structure and reactive site of a novel wheat proteinase inhibitor of subtilisin and chymotrypsin a homodimeric sporamin-type trypsin inhibitor with antiproliferative, hiv reverse transcriptase-inhibitory and antifungal activities from wampee (clausena lansium) seeds bitter gourd proteinase inhibitors: potential growth inhibitors of helicoverpa armigera and spodoptera litura isolation of a trypsin inhibitor with deletion of n-terminal pentapeptide from the seeds of momordica cochinchinensis, the chinese drug mubiezhi protein proteinase inhibitors in legume seed-overview trypsin inhibitor from poecilanthe parviflora seeds: purification, characterization, and activity against pest proteases effects of the medicago scutellata trypsin inhibitor (msti) on cisplatin-induced cytotoxicity in human breast and cervical cancer cells a bowman-birk-type trypsin-chymotrypsin inhibitor from broad beans wolfenstein-todel, c. a novel trypsin inhibitor from peltophorum dubium seeds, with lectin-like properties, triggers rat lymphoma cell apoptosis characterization and pharmacological properties of a novel multifunctional kunitz inhibitor from erythrina velutina seeds formation of bowman-birk inhibitors during the germination of horsegram (dolichos biflorus) reductive unfolding and oxidative refolding of a bowman-birk inhibitor from horsegram seeds (dolichos biflorus): evidence for "hyperreactive" disulfide bonds and rate-limiting nature of disulfide isomerization in folding a comparison of the short and long term effects of insecticidal lectins on the activities of soluble and brush border enzymes of tomato moth larvae (lacanobia oleracea) a mitogenic defensin from white cloud beans (phaseolus vulgaris) purification and characterization of novel ribosome inactivating proteins, alpha-and beta-pisavins, from seeds of the garden pea pisum sativum molecular characterization of a new arcelin-5 gene distribution of proteinases and carbohydrates in the midgut of the larvae of the sweet potato weevil cyclas formicarius and response of proteinase to inhibitors from sweet potato concurrent purification of two defense proteins from french bean seeds: a defensin-like antifungal peptide and a hemagglutinin treatment with field bean protease inhibitor can effectively repress ethylnitrosourea (enu)-induced neoplasms of the nervous system in sprague-dawley rats the field bean protease inhibitor has the potential to suppress b16f10 melanoma cell lung metastasis in mice isolation and characterization of a novel trypsin inhibitor from fresh lily bulbs trypsin-chymotrypsin inhibitors from vigna mungo seeds an antifungal peptide from phaseolus vulgaris cv. brown kidney bean purification and characterization of a lectin from phaseolus vulgaris cv. (anasazi beans) characterization of trypsin inhibitors from tora-mame seeds, one of the japanese cultivars of phaseolus vulgaris trypsin isoinhibitors from garden beans (phaseolus vulgaris) isolation and characterization of some proteinase inhibitors from phaseolus vulgaris var. nanus natural plant enzyme inhibitors: isolation and properties of a trypsin/chymotrypsin inhibitor from kidney bean (phaseolus vulgaris) the isolation and characterization of a trypsin inhibitor from kintoki bean (phaseolus vulgaris) the isolation of two proteins, glycoprotein i and a trypsin inhibitor, from the seeds of kidney bean (phaseolus vulgaris) enzyme inhibitory activities of two leguminosae: phaseolus vulgaris l. pods and vicia faba l. hulls. trypsin inhibitory activity maturation of the head of bacteriophage t4. i. dna packaging events baeyens-volant, d. the papaya kunitz-type trypsin inhibitor is a highly stable beta-sheet glycoprotein a novel lectin from pseudostellaria heterophylla roots with sequence simularity to kunitz-type soybean trypsin inhibitor marmorin, a new ribosome inactivating protein with antiproliferative and hiv-1 reverse transcriptase inhibitory activities from the mushroom hypsizigus marmoreus the authors declare no conflict of interest.molecules 2017, 22, 187 key: cord-300872-blycbi4u authors: saadeh, haythem a.; sweidan, kamal a.; mubarak, mohammad s. title: recent advances in the synthesis and biological activity of 8-hydroxyquinolines date: 2020-09-21 journal: molecules doi: 10.3390/molecules25184321 sha: doc_id: 300872 cord_uid: blycbi4u compounds containing the 8-hydroxyquinoline (8-hq) 1 nucleus exhibit a wide range of biological activities, including antimicrobial, anticancer, and antifungal effects. the chemistry and biology of this group have attracted the attention of chemists, medicinal chemists, and professionals in health sciences. a number of prescribed drugs incorporate this group, and numerous 8-hqbased molecules can be used to develop potent lead compounds with good efficacy and low toxicity. this review focusses on the recent advances in the synthesis of 8-hq derivatives with different pharmacological properties, including anticancer, antiviral, and antibacterial activities. for this purpose, recent relevant references were searched in different known databases and search engines, such as medline (pubmed), google scholar, science direct, scopus, cochrane, scientific information database (sid), scifinder, and institute for scientific information (isi) web of knowledge. this review article provides a literature overview of the various synthetic strategies and biological activities of 8-hq derivatives and covers the recent related literature. taken together, compounds containing the 8-hq moiety have huge therapeutic value and can act as potential building blocks for various pharmacologically active scaffolds. in addition, several described compounds in this review could act leads for the development of drugs against numerous diseases including cancer. 8-hydroxyquinoline derivatives are an important group of compounds with rich and diverse biological activities. these compounds incorporate the 8-hydroxyquinoline (8-hq) moiety, which is a bicyclic compound that consists of a pyridine ring fused to phenol, in which the hydroxyl group is attached to position 8 [1] . in this respect, the pyridine ring maintains its properties as an electron-deficient entity with a basic nitrogen. in addition, and due to the presence of the phenolic group, 8-hq displays typical phenolic properties that make it susceptible to numerous chemical reactions and structural modifications, such as electrophilic aromatic substitution, diazonium coupling, and molecular rearrangements. the close proximity of the hydroxyl group to the heterocyclic nitrogen makes 8-hydroxyquinolines good monoprotic bidentate chelating agents, which form four-and six-covalent complexes with a wide range of metal ions, including cu 2+ , zn 2+ , bi 2+ , mn 2+ , mg 2+ , cd 2+ , ni 2+ , fe 3+ , and al 3+ [2] . figure 1 is a schematic representation of the different sites of reactions of 8-hq. all of the aforementioned properties make 8-hq a privileged structure with a variety of structural modifications, possessing a rich diversity of physical, chemical and biological properties. 8-hydroxyquinoline has attracted the attention of chemists, medicinal chemists, and people in health sciences due to its unique physical and chemical properties. the interest in this compound and its derivatives has increased considerably in the last two decades [3] . 8-hydroxyquinoline and many of its derivatives have a wide range of pharmacological applications, e.g., as iron-chelators for neuroprotection, as anticancer agents, as inhibitors of 2og-dependent enzymes, as chelators of metalloproteins, as anti-hiv agents, as antifungal agents, as antileishmanial agents, as antischistosomal agents, as mycobacterium tuberculosis inhibitors, and as botulinum neurotoxin inhibitors [4] . furthermore, these compounds are used as electron carriers in organic light-emitting diodes (oleds) and as fluorescent chemosensors for metal ions [5, 6] . on the basis of the preceding discussion, and owing to the importance of 8-hq from a chemistry point of view and to the wide range of biological activities and pharmacological applications of 8-hq and derivatives, this review focuses on current knowledge of the synthetic methods of novel derivatives, along with the derivatives' biological activities and medicinal applications. in addition, this review summarizes the most recent literature pertaining to the synthesis and bioactivity of 8-hq and its derivatives, covering the period ranging from 2017 to the present. in addition, structure-activity relationships (sars) of these derivatives are discussed to provide directions for further development of novel 8-hq-based bioactive agents. for this purpose, recent relevant references have been obtained from different databases, such as medical literature retrieval analysis and retrieval system online (medline) (pubmed), google scholar, science direct, scopus, cochrane, sid, and scifinder. our intention is that the content and organization of this review will be valuable to the field and will greatly help researchers. below are details about the recent documented synthesis methods of 8-hq and its derivatives, as well as their biological activities against different diseases and disorders. due to the coronavirus 2019 (covid-19) pandemic and its devastating economic, social, and health effects, we decided to start this study with the antiviral activities of some recent 8-hq derivatives. a few publications have dealt with the antiviral activities of 8-hq and its derivatives. de la guardia et al. described the synthesis of novel 8-hydroxyquinoline derivatives (scheme 1) and investigated their activity against dengue virus [7] . these researchers prepared a number of compounds from 8-hydroxyquinoline n-oxide 2, which upon treatment with copper-catalyzed grignard reagents (rmgx; r = i-pr and i-bu) gave 2-alkyl-8-hydroxyquinoline 3. subsequent chlorination using n-chlorosuccinimide (ncs) under acidic conditions afforded the corresponding 2-alkyl-5,7-dichloro-8-hydroxyquinoline 4 in a good yield. scheme 1. synthesis of 2-isopropy, 2-isobutyl-5,7-dichloro-8-hydroxyquinoline 4. 8-hydroxyquinoline has attracted the attention of chemists, medicinal chemists, and people in health sciences due to its unique physical and chemical properties. the interest in this compound and its derivatives has increased considerably in the last two decades [3] . 8-hydroxyquinoline and many of its derivatives have a wide range of pharmacological applications, e.g., as iron-chelators for neuroprotection, as anticancer agents, as inhibitors of 2og-dependent enzymes, as chelators of metalloproteins, as anti-hiv agents, as antifungal agents, as antileishmanial agents, as antischistosomal agents, as mycobacterium tuberculosis inhibitors, and as botulinum neurotoxin inhibitors [4] . furthermore, these compounds are used as electron carriers in organic light-emitting diodes (oleds) and as fluorescent chemosensors for metal ions [5, 6] . on the basis of the preceding discussion, and owing to the importance of 8-hq from a chemistry point of view and to the wide range of biological activities and pharmacological applications of 8-hq and derivatives, this review focuses on current knowledge of the synthetic methods of novel derivatives, along with the derivatives' biological activities and medicinal applications. in addition, this review summarizes the most recent literature pertaining to the synthesis and bioactivity of 8-hq and its derivatives, covering the period ranging from 2017 to the present. in addition, structure-activity relationships (sars) of these derivatives are discussed to provide directions for further development of novel 8-hq-based bioactive agents. for this purpose, recent relevant references have been obtained from different databases, such as medical literature retrieval analysis and retrieval system online (medline) (pubmed), google scholar, science direct, scopus, cochrane, sid, and scifinder. our intention is that the content and organization of this review will be valuable to the field and will greatly help researchers. below are details about the recent documented synthesis methods of 8-hq and its derivatives, as well as their biological activities against different diseases and disorders. in a similar fashion, kos and coworkers reported the microwave-assisted synthesis of thirty-two mono-, di-, and tri-substituted 8-hydroxyquinoline-2-carboxanilides, as shown in scheme 2 [8] . condensation of activated 8-hydroxyquinoline-2-carboxylic acid (5) with substituted aniline 6 in the presence of by phosphorus trichloride yielded the desired target compound 7 in good amounts (61-79%) . molecules 2020, 25, x for peer review 3 of 26 the antiviral activities of the two novel quinoline derivatives (r = i-pr and i-bu) 4 were evaluated in vitro against the dengue virus serotype 2 (denv2). both exhibited significant inhibitory activities against this virus. the results indicated that the iso-pr-substituted derivative exhibits a half-maximal inhibitory concentration (ic50) of 3.03 µm and a half-maximal cytotoxic concentration (cc50) of 16.06 µm, for an estimated selectivity index (si) of 5.30. on the other hand, the iso-bu derivative was also active, showing a higher si value of 39.5, with an ic50 of 0.49 µm and cc50 of 19.39 µm. the mechanism of action was also investigated and the results showed that these two derivatives are not virucidal, but appear to act at an early stage of the virus lifecycle, reducing the intracellular production of the envelope glycoprotein and the yield of infectious virions in treated and infected cells. in a similar fashion, kos and coworkers reported the microwave-assisted synthesis of thirty-two mono-, di-, and tri-substituted 8-hydroxyquinoline-2-carboxanilides, as shown in scheme 2 [8] . condensation of activated 8-hydroxyquinoline-2-carboxylic acid (5) with substituted aniline 6 in the presence of by phosphorus trichloride yielded the desired target compound 7 in good amounts (61-79%). these prepared compounds were subjected to bioactivity screening against the highly pathogenic h5n1 avian influenza viruses, with the results expressed as percentages of growth inhibition, and to cytotoxicity evaluation against the a549 cell line. the lipophilicity and electronic properties were the molecular parameters used to determine the structure-activity relationship. the lipophilicity of the studied compounds was determined as a log k value using reversed-phase highperformance liquid chromatography (rp-hplc). based on the presented results, most monosubstituted derivatives did not exert any antiviral activity or demonstrated only moderate activity. for example, 8-hydroxy-n-(3-nitrophenyl)quinoline-2-carboxamide showed optimum virus growth inhibition activity and cytotoxicity values of 85.0% and 4%, respectively. furthermore, the results show that the antiviral activity is influenced by increasing the electron-withdrawing properties of substituents on the anilide ring and is positively influenced by increasing the lipophilicity; in this manner, the derivative showing values of r = 3-no2 and log k = ca. 0.41 showed maximal activity with insignificant cytotoxicity. di-and tri-substituted derivatives (r = 3,4-cl, 3,4,5-cl, 3-cl-2-f, and 2,4-no2) showed higher inhibition of h5n1 growth and simultaneous low cytotoxicity. for example, 3-cl-2-f and 3,4,5-cl exhibited virus growth inhibition activity values of 91.2 and 9.7% and cytotoxicity values of 79.3 and 2.4%, respectively; the log k values for these derivatives were 1.44 and 1.26, respectively. the study indicated that the antiviral activity linearly increases with increasing lipophilicity and is positively influenced by increasing the electron-withdrawing properties of substituents on the anilide ring. with the frantic search for drugs to treat covid-19 patients and ultimately for a covid-19 vaccine, the 8-hq nucleus could play a role in this due to its promising antiviral activity; however, more research is required in this area. the spread of the antibiotic-resistant bacterial strains constitutes a serious threat to public health. some of these strains have even become resistant to many antibiotics and chemotherapeutic agents; these prepared compounds were subjected to bioactivity screening against the highly pathogenic h5n1 avian influenza viruses, with the results expressed as percentages of growth inhibition, and to cytotoxicity evaluation against the a549 cell line. the lipophilicity and electronic properties were the molecular parameters used to determine the structure-activity relationship. the lipophilicity of the studied compounds was determined as a log k value using reversed-phase high-performance liquid chromatography (rp-hplc). based on the presented results, most mono-substituted derivatives did not exert any antiviral activity or demonstrated only moderate activity. for example, 8-hydroxy-n-(3-nitrophenyl)quinoline-2-carboxamide showed optimum virus growth inhibition activity and cytotoxicity values of 85.0% and 4%, respectively. furthermore, the results show that the antiviral activity is influenced by increasing the electron-withdrawing properties of substituents on the anilide ring and is positively influenced by increasing the lipophilicity; in this manner, the derivative showing values of r = 3-no 2 and log k = ca. 0.41 showed maximal activity with insignificant cytotoxicity. di-and tri-substituted derivatives (r = 3,4-cl, 3,4,5-cl, 3-cl-2-f, and 2,4-no 2 ) showed higher inhibition of h5n1 growth and simultaneous low cytotoxicity. for example, 3-cl-2-f and 3,4,5-cl exhibited virus growth inhibition activity values of 91.2 and 9.7% and cytotoxicity values of 79.3 and 2.4%, respectively; the log k values for these derivatives were 1.44 and 1.26, respectively. the study indicated that the antiviral activity linearly increases with increasing lipophilicity and is positively influenced by increasing the electron-withdrawing properties of substituents on the anilide ring. with the frantic search for drugs to treat covid-19 patients and ultimately for a covid-19 vaccine, the 8-hq nucleus could play a role in this due to its promising antiviral activity; however, more research is required in this area. the spread of the antibiotic-resistant bacterial strains constitutes a serious threat to public health. some of these strains have even become resistant to many antibiotics and chemotherapeutic agents; hence, the term "multidrug resistance" has been introduced in the literature. thus, the development of existing drugs and the discovery of new leads are major strategies used to combat the threat of these multidrug-resistant strains. in this context, hu and coworkers prepared new derivatives of the known potent antibacterial agent 2,6-difluoro-3-hydroxybenzamide (dfmba) [9] . the substituted 8-hq 8 was alkylated with 1,3-dibromopropane in the presence of an aqueous sodium hydroxide solution and tetrabutylammonium iodide (tbai) in dichloromethane to afford a mono-halogenated intermediate 9. target compound 10 was obtained via alkylation of dfmba with the corresponding 8-hq mono bromide (scheme 3). molecules 2020, 25, x for peer review 4 of 26 hence, the term "multidrug resistance" has been introduced in the literature. thus, the development of existing drugs and the discovery of new leads are major strategies used to combat the threat of these multidrug-resistant strains. in this context, hu and coworkers prepared new derivatives of the known potent antibacterial agent 2,6-difluoro-3-hydroxybenzamide (dfmba) [9] . the substituted 8-hq 8 was alkylated with 1,3-dibromopropane in the presence of an aqueous sodium hydroxide solution and tetrabutylammonium iodide (tbai) in dichloromethane to afford a mono-halogenated intermediate 9. target compound 10 was obtained via alkylation of dfmba with the corresponding 8-hq mono bromide (scheme 3). scheme 3. synthesis of 2,6-difluoro-3-hydroxybenzamide-8-hydroxyquinoline derivatives. the antibacterial activity of these derivatives was evaluated against several gram-positive and gram-negative bacteria using the zone-of-inhibition test. inhibition zones were compared to the standard antibiotic pc190723 (11) , which is an effective bactericidal cell division inhibitor that targets cell division protein (ftsz) in several gram-positive bacteria. the results showed that the antibacterial activities were lower than that of pc190723. in addition, the highest inhibition zone ratios (inhibition zone of the test compound/inhibition zone of the standard) of 0.25 and 0.18 against s. aureus were observed for derivatives where r = 5-cl and 5,7-dicl, respectively. moreover, when comparing the activity of 8-hq derivatives with 8-hq naphthalene analogues, the former were more active; this is probably due to the ring nitrogen, which may increase the polarity and water solubility of the compounds-factors that are required for antibacterial activity. krishna reported the synthesis of a series of new 5-amino-7-bromoquinolin-8-yl sulfonates 15 in good yield using a multistep synthesis method [10] . bromination of 8-hydroxquinoline 1 with nbromosuccinimide (nbs) in chloroform afforded 7-bromoquinolin-8-ol, which upon treatment with nano2/hcl followed by reduction with na2s2o4 in 1:1 tetrahydrofuran (thf) and water gave 5amino-7-bromoquinolin-8-ol 14. the target sulfonate derivatives 15 were obtained from 5-amino-7bromoquinolin-8-ol by reaction with various sulfonyl chlorides in dry thf in the presence of triethylamine (tea) (scheme 4). the antibacterial activity of these derivatives was evaluated against several gram-positive and gram-negative bacteria using the zone-of-inhibition test. inhibition zones were compared to the standard antibiotic pc190723 (11) , which is an effective bactericidal cell division inhibitor that targets cell division protein (ftsz) in several gram-positive bacteria. the results showed that the antibacterial activities were lower than that of pc190723. in addition, the highest inhibition zone ratios (inhibition zone of the test compound/inhibition zone of the standard) of 0.25 and 0.18 against s. aureus were observed for derivatives where r = 5-cl and 5,7-dicl, respectively. moreover, when comparing the activity of 8-hq derivatives with 8-hq naphthalene analogues, the former were more active; this is probably due to the ring nitrogen, which may increase the polarity and water solubility of the compounds-factors that are required for antibacterial activity. krishna reported the synthesis of a series of new 5-amino-7-bromoquinolin-8-yl sulfonates 15 in good yield using a multistep synthesis method [10] . bromination of 8-hydroxquinoline 1 with n-bromosuccinimide (nbs) in chloroform afforded 7-bromoquinolin-8-ol, which upon treatment with nano 2 /hcl followed by reduction with na 2 s 2 o 4 in 1:1 tetrahydrofuran (thf) and water gave 5-amino-7-bromoquinolin-8-ol 14. the target sulfonate derivatives 15 were obtained from 5-amino-7-bromoquinolin-8-ol by reaction with various sulfonyl chlorides in dry thf in the presence of triethylamine (tea) (scheme 4). the newly synthesized sulfonate 15 derivatives were tested against several bacterial strains, such as staphylococcus aureus and bacillus megaterium (gram-positive bacteria), klebsiella pneumoniae and pseudomonas aeruginosa (gram-negative bacteria), and against two gram-negative, antibioticresistant e. coli bacterial strains, namely mutant e. coli (streptomycin-resistant) and donor e. coli (rifampin-resistant), using the agar well diffusion method; amoxiclav (ac) was used as the standard drug. among the synthesized compounds, derivatives with an aryl group showed potent activity. for example, the compound with ar = biphenyl exhibited potent activity against staphylococcus aureus, with an inhibition zone of 22 mm compared to the reference drug (24 mm). on the other hand, derivatives with ar = 4-fph and 2-oh-5-no2ph displayed potent activity against pseudomonas aeruginosa, with inhibition zones of 22 mm and 23 mm, respectively, compared to the standard drug (24 mm), whereas the derivative with r = 4-ch3ph was potent against klebsiella pneumonia, with an inhibition zone of 25 mm compared to the standard drug (27 mm these compounds were tested as antibacterial agents against six pathogenic strains, including e. cloacae, e. coli, k. pneumoniae, p. aeruginosa, s. aureus, and a. baumanii. minimal inhibitory concentrations of these compounds were calculated and compared with three standard antibiotics, namely penicillin g, norfloxacin, and erythromycin, using the disk diffusion technique. some of these prepared compounds exhibited remarkable antibacterial activity against gram-positive and gramnegative strains compared to the standard antibiotics used. one derivative (r = no2, r′ = h) was more potent than the standard drugs and showed activity against e. cloacae, k. pneumoniae, s. aureus, the newly synthesized sulfonate 15 derivatives were tested against several bacterial strains, such as staphylococcus aureus and bacillus megaterium (gram-positive bacteria), klebsiella pneumoniae and pseudomonas aeruginosa (gram-negative bacteria), and against two gram-negative, antibiotic-resistant e. coli bacterial strains, namely mutant e. coli (streptomycin-resistant) and donor e. coli (rifampin-resistant), using the agar well diffusion method; amoxiclav (ac) was used as the standard drug. among the synthesized compounds, derivatives with an aryl group showed potent activity. for example, the compound with ar = biphenyl exhibited potent activity against staphylococcus aureus, with an inhibition zone of 22 mm compared to the reference drug (24 mm). on the other hand, derivatives with ar = 4-fph and 2-oh-5-no 2 ph displayed potent activity against pseudomonas aeruginosa, with inhibition zones of 22 mm and 23 mm, respectively, compared to the standard drug (24 mm), whereas the derivative with r = 4-ch 3 ph was potent against klebsiella pneumonia, with an inhibition zone of 25 mm compared to the standard drug (27 mm) . a study published by rbaa the newly synthesized sulfonate 15 derivatives were tested against several bacterial strains, such as staphylococcus aureus and bacillus megaterium (gram-positive bacteria), klebsiella pneumoniae and pseudomonas aeruginosa (gram-negative bacteria), and against two gram-negative, antibioticresistant e. coli bacterial strains, namely mutant e. coli (streptomycin-resistant) and donor e. coli (rifampin-resistant), using the agar well diffusion method; amoxiclav (ac) was used as the standard drug. among the synthesized compounds, derivatives with an aryl group showed potent activity. for example, the compound with ar = biphenyl exhibited potent activity against staphylococcus aureus, with an inhibition zone of 22 mm compared to the reference drug (24 mm). on the other hand, derivatives with ar = 4-fph and 2-oh-5-no2ph displayed potent activity against pseudomonas aeruginosa, with inhibition zones of 22 mm and 23 mm, respectively, compared to the standard drug (24 mm), whereas the derivative with r = 4-ch3ph was potent against klebsiella pneumonia, with an inhibition zone of 25 mm compared to the standard drug (27 mm) . a study published by rbaa these compounds were tested as antibacterial agents against six pathogenic strains, including e. cloacae, e. coli, k. pneumoniae, p. aeruginosa, s. aureus, and a. baumanii. minimal inhibitory concentrations of these compounds were calculated and compared with three standard antibiotics, namely penicillin g, norfloxacin, and erythromycin, using the disk diffusion technique. some of these prepared compounds exhibited remarkable antibacterial activity against gram-positive and gramnegative strains compared to the standard antibiotics used. one derivative (r = no2, r′ = h) was more potent than the standard drugs and showed activity against e. cloacae, k. pneumoniae, s. aureus, these compounds were tested as antibacterial agents against six pathogenic strains, including e. cloacae, e. coli, k. pneumoniae, p. aeruginosa, s. aureus, and a. baumanii. minimal inhibitory concentrations of these compounds were calculated and compared with three standard antibiotics, namely penicillin g, norfloxacin, and erythromycin, using the disk diffusion technique. some of these prepared compounds exhibited remarkable antibacterial activity against gram-positive and gram-negative strains compared to the standard antibiotics used. one derivative (r = no 2 , r = h) was more potent than the standard drugs and showed activity against e. cloacae, k. pneumoniae, s. aureus, a. baumanii, e. coli, e. cloacae, and e. cloaca, with minimum inhibitory concentration (mic) values (mg/ml) of 1 × 10 −6 , 1 × 10 −5 , 1 × 10 −5 , 1 × 10 −4 , and 1 × 10 −4 , respectively, while the mic for the standard drug was 1 × 10 −4 . derivatives with r = r = h and r = h, r = cl displayed similar activities against s. aureus, with mic values of 1 × 10 −4 . bioinformatic petra, osiris, and molinspiration (pom) analyses indicated that all compounds exhibit good bioavailability and less toxic profiles when compared with penicillin g. interestingly, two research groups have reported on the hybridization of 8-hydroxyquinoline with ciprofloxacin in a single step and evaluated the antibacterial activity of the hybrid molecule. fu et al. reported the synthesis of 5-chloro-8-hydroxyquinoline-ciprofloxacin 19 via the mannich reaction (scheme 6). thus, 5-chloro-8-hydroxyquinoline 18 reacted with ciprofloxacin in the presence of paraformaldehyde in ethanol to afford the hybrid product at 75% yield [12] . interestingly, two research groups have reported on the hybridization of 8-hydroxyquinoline with ciprofloxacin in a single step and evaluated the antibacterial activity of the hybrid molecule. fu et al. reported the synthesis of 5-chloro-8-hydroxyquinoline-ciprofloxacin 19 via the mannich reaction (scheme 6). thus, 5-chloro-8-hydroxyquinoline 18 reacted with ciprofloxacin in the presence of paraformaldehyde in ethanol to afford the hybrid product at 75% yield [12] . the hybrid 19 was screened against both gram-positive and gram-negative (staphylococcus epidermidis, s. aureus, enterococci faecalis, and e. faecium) bacterial strains, and the minimum inhibitory concentrations (mics) were determined via the agar dilution method. the results indicated that the hybrid shows exciting promise against both gram-positive and gram-negative bacteria. it displayed significant effects against both susceptible and drug-resistant strains, with mic values of 4-16 µg/ml. these values were lower than those of standard drug (ciprofloxacin), which has mic values of 0.125-0.5 µg/ml. however, the authors speculated that the introduction of a quinolone skeleton might be an effective way to modify these kinds of compounds into a novel class of broad-spectrum antibacterial agents with a specific mode of action. on the other hand, vu and coworkers prepared a hybrid compound 21 at 96% yield through coupling of 8-hydroxyquinoline-2-carboxylic acid 20 and ciprofloxacin by using 2-(1h-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (tbtu) and n,n-diisopropylethylamine (diea) (scheme 7) [13] . the hybrid 19 was screened against both gram-positive and gram-negative (staphylococcus epidermidis, s. aureus, enterococci faecalis, and e. faecium) bacterial strains, and the minimum inhibitory concentrations (mics) were determined via the agar dilution method. the results indicated that the hybrid shows exciting promise against both gram-positive and gram-negative bacteria. it displayed significant effects against both susceptible and drug-resistant strains, with mic values of 4-16 µg/ml. these values were lower than those of standard drug (ciprofloxacin), which has mic values of 0.125-0.5 µg/ml. however, the authors speculated that the introduction of a quinolone skeleton might be an effective way to modify these kinds of compounds into a novel class of broad-spectrum antibacterial agents with a specific mode of action. on the other hand, vu and coworkers prepared a hybrid compound 21 at 96% yield through coupling of 8-hydroxyquinoline-2-carboxylic acid 20 and ciprofloxacin by using 2-(1h-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (tbtu) and n,n-diisopropylethylamine (diea) (scheme 7) [13] . interestingly, two research groups have reported on the hybridization of 8-hydroxyquinoline with ciprofloxacin in a single step and evaluated the antibacterial activity of the hybrid molecule. fu et al. reported the synthesis of 5-chloro-8-hydroxyquinoline-ciprofloxacin 19 via the mannich reaction (scheme 6). thus, 5-chloro-8-hydroxyquinoline 18 reacted with ciprofloxacin in the presence of paraformaldehyde in ethanol to afford the hybrid product at 75% yield [12] . the hybrid 19 was screened against both gram-positive and gram-negative (staphylococcus epidermidis, s. aureus, enterococci faecalis, and e. faecium) bacterial strains, and the minimum inhibitory concentrations (mics) were determined via the agar dilution method. the results indicated that the hybrid shows exciting promise against both gram-positive and gram-negative bacteria. it displayed significant effects against both susceptible and drug-resistant strains, with mic values of 4-16 µg/ml. these values were lower than those of standard drug (ciprofloxacin), which has mic values of 0.125-0.5 µg/ml. however, the authors speculated that the introduction of a quinolone skeleton might be an effective way to modify these kinds of compounds into a novel class of broad-spectrum antibacterial agents with a specific mode of action. on the other hand, vu and coworkers prepared a hybrid compound 21 at 96% yield through coupling of 8-hydroxyquinoline-2-carboxylic acid 20 and ciprofloxacin by using 2-(1h-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (tbtu) and n,n-diisopropylethylamine (diea) (scheme 7) [13] . the hybrid was screened for cell toxicity against hela cells, a tumor cell line, primary cell cultures of mouse fibroblasts, and against non-cancerous mammalian cell line. it showed no cell toxicity at the concentrations tested (0-200 µm). then, the antibacterial activity was tested against gram-negative and gram-positive bacteria, including pathogenic bacteria present in the hospital environment that are difficult to treat (enterococcus faecium, staphylococcus aureus, klebsiella pneumoniae, acinetobacter baumannii, pseudomonas aeruginosa, and enterobacter species). the results indicated that that hybrid 21 exhibits more potent activity than the standard drug against staphylococcus aureus, with an mic (mg/ml) value of 0.0625 (mic of the standard drug = 0.125). however, the hybrid was less active against the rest of the pathogens as compared to the standard drug. in general, the two aforementioned hybrids were systematically less active than the parent antibiotic, ciprofloxacin. from these published data, it is obvious that 8-hq could be an important motif for future antibacterial drugs, especially against antibiotic-resistant strains. however, more research is required, including experiments with animals using newly synthesized antibacterial agents. fungal resistance to antifungal agents has become a problem and a challenge to scientists in recent years. this resistance has serious implications for morbidity, mortality, and health care costs worldwide. hence, attention has been given to understanding the mechanism of antifungal resistance in order to develop new treatments and strategies to manage infections caused by resistant organisms. along this line, le pan and colleagues reported the synthesis of conjugates of 7-hydroxycoumarin (umbelliferone) with several heterocylic rings, including 4-and 8-hydroxyquinolines [14] . 7-hydroxycoumarin was mono-alkylated in moderate yields via an excess of br-(ch 2 ) n -br (n = 2,4) in refluxing acetone in the presence of k 2 co 3 -naoh (2:1). bromoalkylated coumarins were then reacted with 4-and 8-hydroxyquinoline in the presence of 1 equivalent of koh and catalytic amounts of ki and tetra-n-butylammonium bromide (tbab) as a phase transfer catalyst in refluxing acetonitrile to give the corresponding conjugates at 55-80% yields (scheme 8). molecules 2020, 25, x for peer review 7 of 26 indicated that that hybrid 21 exhibits more potent activity than the standard drug against staphylococcus aureus, with an mic (mg/ml) value of 0.0625 (mic of the standard drug = 0.125). however, the hybrid was less active against the rest of the pathogens as compared to the standard drug. in general, the two aforementioned hybrids were systematically less active than the parent antibiotic, ciprofloxacin. from these published data, it is obvious that 8-hq could be an important motif for future antibacterial drugs, especially against antibiotic-resistant strains. however, more research is required, including experiments with animals using newly synthesized antibacterial agents. fungal resistance to antifungal agents has become a problem and a challenge to scientists in recent years. this resistance has serious implications for morbidity, mortality, and health care costs worldwide. hence, attention has been given to understanding the mechanism of antifungal resistance in order to develop new treatments and strategies to manage infections caused by resistant organisms. along this line, le pan and colleagues reported the synthesis of conjugates of 7hydroxycoumarin (umbelliferone) with several heterocylic rings, including 4-and 8hydroxyquinolines [14] . 7-hydroxycoumarin was mono-alkylated in moderate yields via an excess of br-(ch2)n-br (n = 2,4) in refluxing acetone in the presence of k2co3-naoh (2:1). bromoalkylated coumarins were then reacted with 4-and 8-hydroxyquinoline in the presence of 1 equivalent of koh and catalytic amounts of ki and tetra-n-butylammonium bromide (tbab) as a phase transfer catalyst in refluxing acetonitrile to give the corresponding conjugates at 55-80% yields (scheme 8). the antifungal activity of these new conjugates against four phytopathogenic fungi (a. alternate, a. solani, b. cinerea, and f. oxysporum) was evaluated by measuring the mycelial inhibition of radial growth on potato dextrose agar (pda) media compared to the commercial fungicide carbendazim. the inhibition percentages of radial growth against all of these fungi for umbelliferone-8hydroxyquinoline (n = 2), umbelliferone-8-hydroxyquinoline (n = 4), and umbelliferone-4hydroxyquinoline (n = 4) were 49-63, 57-90, and 18-41%, respectively, compared to carbendazim (95-99%) at 200 µg/ml concentration. when these derivatives were tested at a series of lower concentrations to measure the half-maximal effective concentration (µg/ml), umbelliferone-8hydroxyquinoline (n = 4) was the most active compared to the reference drug at 10.6 and 2.3 µg/ml, respectively. the rest of the 8-hydroxyquinoline derivatives exhibited weak activity. the results also showed that umbelliferone derivatives with a spacer of 4 carbon atoms exhibit better antifungal the antifungal activity of these new conjugates against four phytopathogenic fungi (a. alternate, a. solani, b. cinerea, and f. oxysporum) was evaluated by measuring the mycelial inhibition of radial growth on potato dextrose agar (pda) media compared to the commercial fungicide carbendazim. the inhibition percentages of radial growth against all of these fungi for umbelliferone-8-hydroxyquinoline (n = 2), umbelliferone-8-hydroxyquinoline (n = 4), and umbelliferone-4-hydroxyquinoline (n = 4) were 49-63, 57-90, and 18-41%, respectively, compared to carbendazim (95-99%) at 200 µg/ml concentration. when these derivatives were tested at a series of lower concentrations to measure the half-maximal effective concentration (µg/ml), umbelliferone-8-hydroxyquinoline (n = 4) was the most active compared to the reference drug at 10.6 and 2.3 µg/ml, respectively. the rest of the 8-hydroxyquinoline derivatives exhibited weak activity. the results also showed that umbelliferone derivatives with a spacer of 4 carbon atoms exhibit better antifungal activity than those with a spacer of 2 carbon atoms. the chain length may contribute to the activity by influencing the flexibility of the molecules. in addition, the position of the oh group affects the antifungal activity; derivatives with oh at position 8 were more active than those with oh at position 4. the structure-activity relationship suggests that modification of the umbelliferone-8-hysroxyquinoline analogues could help to develop highly selective and low phytotoxic fungicides. the phytotoxicity of effective compounds was evaluated at 200 mg/l with l. sativa, with the results showing that umbelliferone-8-hysroxyquinoline (n = 4) had no phytotoxic effects on the seedling growth of lettuce. yurras and coworkers have reported on the multistep synthesis of novel 3,4,5-trisubstituted triazole derivatives bearing 8-hydroxyquinoline 31, evaluating their antimicrobial activity [15] . synthesis was achieved by first reacting 8-hydroxyquinoline 1 with ethyl 2-chloroacetate in refluxing acetone in the presence of a base. treatment of the formed ester 26 with hydrazine hydrate in ethanol followed by phenyl isocyanate afforded the corresponding thiourea 28. ring closure using koh in refluxing ethanol led to the formation of 3-mercapto-1,2,4-triazole derivative 29. reaction of 3-mercapto-1,2,4-triazole with 2-chloro-n-(substituted (benzo)/thiazole)acetamide 30 afforded the target compounds, as depicted in scheme 9. molecules 2020, 25, x for peer review 8 of 26 activity than those with a spacer of 2 carbon atoms. the chain length may contribute to the activity by influencing the flexibility of the molecules. in addition, the position of the oh group affects the antifungal activity; derivatives with oh at position 8 were more active than those with oh at position 4. the structure-activity relationship suggests that modification of the umbelliferone-8hysroxyquinoline analogues could help to develop highly selective and low phytotoxic fungicides. the phytotoxicity of effective compounds was evaluated at 200 mg/l with l. sativa, with the results showing that umbelliferone-8-hysroxyquinoline (n = 4) had no phytotoxic effects on the seedling growth of lettuce. yurras and coworkers have reported on the multistep synthesis of novel 3,4,5-trisubstituted triazole derivatives bearing 8-hydroxyquinoline 31, evaluating their antimicrobial activity [15] . synthesis was achieved by first reacting 8-hydroxyquinoline 1 with ethyl 2-chloroacetate in refluxing acetone in the presence of a base. treatment of the formed ester 26 with hydrazine hydrate in ethanol followed by phenyl isocyanate afforded the corresponding thiourea 28. ring closure using koh in refluxing ethanol led to the formation of 3-mercapto-1,2,4-triazole derivative 29. reaction of 3mercapto-1,2,4-triazole with 2-chloro-n-(substituted (benzo)/thiazole)acetamide 30 afforded the target compounds, as depicted in scheme 9. some sulfonates reported by krishna (scheme 4) were also tested in vitro against aspergillus niger and penicillium spinulosum fungal strains by the poison plate technique; fluconazole was used as a standard drug for antifungal activity. two compounds with ar = biphenyl and ar = 2-nitro-5-hydroxybenzene exhibited the most potent antifungal activity against aspergillus niger, with inhibition zones of 10 and 13 mm, respectively, compared to fluconazole (15 mm); and against penicillium spinulosum, with inhibition zones of 12 and 10 mm, respectively, compared to fluconazole (12 mm). cancer is a dreadful disease that has become a global burden, causing thousands of deaths per year, despite the technological and pharmaceutical improvements over the past several years. it has emerged as one of the leading causes of mortality worldwide [16] . cancer treatments include surgery, radiotherapy, and anticancer drugs (chemotherapy), in addition to other specialized techniques. much scientific effort is being made every day in the fight against cancer, but successful treatment of some cancer types is still a challenge that needs more work [17] . on the synthetic front in the fight against cancer, two new series of derivatives have been prepared where the bioactive quinolone motif is incorporated, as shown in scheme 10 [18] . 6-bromo-8-methoxyquinoline (1) was prepared according to a published procedure [19] . afterwards, compound 32 was subjected to a suzuki cross-coupling reaction with p-formphenylboronic (33) acid to afford synthon 34 in excellent yield. all target products (35) were synthesized via a simple and effective method using a one-pot mannich-type reaction that involves a reaction of amines, carbonyl compounds, and dialkylphosphonate. molecules 2020, 25, x for peer review 9 of 26 some sulfonates reported by krishna (scheme 4) were also tested in vitro against aspergillus niger and penicillium spinulosum fungal strains by the poison plate technique; fluconazole was used as a standard drug for antifungal activity. two compounds with ar = biphenyl and ar = 2-nitro-5hydroxybenzene exhibited the most potent antifungal activity against aspergillus niger, with inhibition zones of 10 and 13 mm, respectively, compared to fluconazole (15 mm); and against penicillium spinulosum, with inhibition zones of 12 and 10 mm, respectively, compared to fluconazole (12 mm). cancer is a dreadful disease that has become a global burden, causing thousands of deaths per year, despite the technological and pharmaceutical improvements over the past several years. it has emerged as one of the leading causes of mortality worldwide [16] . cancer treatments include surgery, radiotherapy, and anticancer drugs (chemotherapy), in addition to other specialized techniques. much scientific effort is being made every day in the fight against cancer, but successful treatment of some cancer types is still a challenge that needs more work [17] . on the synthetic front in the fight against cancer, two new series of derivatives have been prepared where the bioactive quinolone motif is incorporated, as shown in scheme 10 [18] . 6-bromo-8-methoxyquinoline (1) was prepared according to a published procedure [19] . afterwards, compound 32 was subjected to a suzuki crosscoupling reaction with p-formphenylboronic (33) acid to afford synthon 34 in excellent yield. all target products (35) were synthesized via a simple and effective method using a one-pot mannichtype reaction that involves a reaction of amines, carbonyl compounds, and dialkylphosphonate. the cytotoxicity of these prepared compounds against esophageal (eca109) and hepatocellular (huh7) cancer cell lines was evaluated using sunitinib as a positive control. the results showed that most of these compounds exhibit moderate to high activity, with ic50 values ranging from 2.26 to 7.46 µmol/l for the two most promising derivatives containing 2-methylphenyl and 4-methylphenyl groups for r 2 and iso-propyl for r 1 ; some of these compounds exhibited inhibition activities comparable to those of sunitinib, which showed ic50 values of 16.54 and 5.27 µmol/l towards eca109 and huh7, respectively. furthermore, the results indicated that ethyl and isopropyl substituents of phosphonate have no major effects on the cytotoxicity activity, while substituents on the phenyl ring showed significant influence on the bioactivity. the cytotoxicity of these prepared compounds against esophageal (eca109) and hepatocellular (huh7) cancer cell lines was evaluated using sunitinib as a positive control. the results showed that most of these compounds exhibit moderate to high activity, with ic 50 values ranging from 2.26 to 7.46 µmol/l for the two most promising derivatives containing 2-methylphenyl and 4-methylphenyl groups for r 2 and iso-propyl for r 1 ; some of these compounds exhibited inhibition activities comparable to those of sunitinib, which showed ic 50 values of 16.54 and 5.27 µmol/l towards eca109 and huh7, respectively. furthermore, the results indicated that ethyl and isopropyl substituents of phosphonate have no major effects on the cytotoxicity activity, while substituents on the phenyl ring showed significant influence on the bioactivity. faydy and coworkers described the synthesis of new derivatives of 8-hydroxyquinoline (36-38) ( figure 2 ) in a multistep approach [20] according to published procedures [21] [22] [23] . the antioxidant activity of prepared products, along with l-ascorbic acid, was evaluated by means of the free radical scavenging method using the 2,2-diphenyl-1-picryhydrazyl (dpph) assay. the results revealed that all products showed low antioxidant activity, with ic 50 values of 0.8-2.49 mg/ml, whereas the ic 50 value of 1-ascorbic acid was 0.1 mg/ml. furthermore, the results showed that as the number of hydroxyl groups increases, the inhibition activity increases too. molecules 2020, 25, x for peer review 10 of 26 faydy and coworkers described the synthesis of new derivatives of 8-hydroxyquinoline (36-38) ( figure 2 ) in a multistep approach [20] according to published procedures [21] [22] [23] . the antioxidant activity of prepared products, along with l-ascorbic acid, was evaluated by means of the free radical scavenging method using the 2,2-diphenyl-1-picryhydrazyl (dpph) assay. the results revealed that all products showed low antioxidant activity, with ic50 values of 0.8-2.49 mg/ml, whereas the ic50 value of 1-ascorbic acid was 0.1 mg/ml. furthermore, the results showed that as the number of hydroxyl groups increases, the inhibition activity increases too. [24] following a published procedure [25] . the structures of prepared compounds were confirmed with the aid of a panel of spectroscopic methods, including 1 h nmr, 13 the prepared compounds were then subjected to cell viability evaluation against hela, mcf-7, a-549, and mda-mb-231 (triple-negative breast cancer cell line) cell lines using the mtt assay [26] [27] [28] at a concentration of 20 mm. the results revealed that only 4 compounds designated with r = phenyl, 3,5-dimethylphenyl, 4-fluorophenyl, and 4-trifluoromethylphenyl exhibited significantly reduced cell viability percentages towards the tested cancer cell lines. the ic50 values for these compounds were between 26.30 and 63.75 mm against selected cancer cell lines, whereas the ic50 of docetaxel (positive control) was in the range of 3.37-4.46 mm. a new series of glycoconjugates composed of various sugar units (40, 41) (d-glucose or dgalactose) and 8-hydroxyquinolines (42, 43) was prepared in an effective and simple method [29] . the connection between these units was accomplished by o-glycosidic bond or via o-methylene 1,2,3-triazole linker, as shown in scheme 11. sugar derivatives of 44 and 45 were prepared according to published procedures [30] [31] [32] ; sugar was used to enhance the bioavailability and solubility of potential drugs. (figure 3 ) in moderate to excellent yields [24] following a published procedure [25] . the structures of prepared compounds were confirmed with the aid of a panel of spectroscopic methods, including 1 h nmr, 13 c nmr, ir, and hrms. molecules 2020, 25, x for peer review 10 of 26 faydy and coworkers described the synthesis of new derivatives of 8-hydroxyquinoline (36-38) ( figure 2 ) in a multistep approach [20] according to published procedures [21] [22] [23] . the antioxidant activity of prepared products, along with l-ascorbic acid, was evaluated by means of the free radical scavenging method using the 2,2-diphenyl-1-picryhydrazyl (dpph) assay. the results revealed that all products showed low antioxidant activity, with ic50 values of 0.8-2.49 mg/ml, whereas the ic50 value of 1-ascorbic acid was 0.1 mg/ml. furthermore, the results showed that as the number of hydroxyl groups increases, the inhibition activity increases too. (figure 3 ) in moderate to excellent yields [24] following a published procedure [25] . the structures of prepared compounds were confirmed with the aid of a panel of spectroscopic methods, including 1 h nmr, 13 (42, 43) was prepared in an effective and simple method [29] . the connection between these units was accomplished by o-glycosidic bond or via o-methylene 1,2,3-triazole linker, as shown in scheme 11. sugar derivatives of 44 and 45 were prepared according to published procedures [30] [31] [32] ; sugar was used to enhance the bioavailability and solubility of potential drugs. (42, 43) was prepared in an effective and simple method [29] . the connection between these units was accomplished by o-glycosidic bond or via o-methylene 1,2,3-triazole linker, as shown in scheme 11. sugar derivatives of 44 and 45 were prepared according to published procedures [30] [31] [32] ; sugar was used to enhance the bioavailability and solubility of potential drugs. all prepared derivatives were tested against different cancer cell lines, including hela, hct 116, and mcf-7, in addition to a normal human dermal neonatal fibroblast (nhdf-neo). compound 2, designated with r = r 1 = h and r 2 = oac, was the most active, with ic 50 values of 30.98, 22.7, and 4.12 mm against hela, hct 116, and mcf-7, respectively. other derivatives exhibited low bioactivity. this could be attributed to the use of the quinolone hydroxyl group to form a glycosidic linkage, which impedes the chelation of metal ions due to steric hindrance. in this respect, it should be stated that the presence of the 1,2,3-triazole moiety improves the activity of glycoconjugates, whereas the type of sugar fragment did not affect the activity significantly. finally, conjugates with a sugar moiety and free hydroxyl group exerted better inhibitory potential than acetylated analogs. all prepared derivatives were tested against different cancer cell lines, including hela, hct 116, and mcf-7, in addition to a normal human dermal neonatal fibroblast (nhdf-neo). compound 2, designated with r = r1 = h and r2 = oac, was the most active, with ic50 values of 30.98, 22.7, and 4.12 mm against hela, hct 116, and mcf-7, respectively. other derivatives exhibited low bioactivity. this could be attributed to the use of the quinolone hydroxyl group to form a glycosidic linkage, which impedes the chelation of metal ions due to steric hindrance. in this respect, it should be stated that the presence of the 1,2,3-triazole moiety improves the activity of glycoconjugates, whereas the type of sugar fragment did not affect the activity significantly. finally, conjugates with a sugar moiety and free hydroxyl group exerted better inhibitory potential than acetylated analogs. fouda published a paper dealing with the synthesis, characterization, and cytotoxicity of new derivatives of halogenated 2-amino-4-aryl-4-pyrano[3,2-h]quinolone-3-carbonitrile (48) derivatives (scheme 12) [33] . these derivatives were prepared through interactions of various 8hydroxyquinolines (46) with α-cyanocinnamonitriles (47) . these prepared compounds were screened for potential anticancer activity against mcf-7, hct 116, hepg-2, and a549 using the mmt assay. structure-activity relationship (sar) results revealed that 6-chloroanalogues were the most active, whereas the 9-methylanaloguess were the least potent. in addition, the lipophilicity of the products increased in the presence of halogen atom substituents at positions 4, 6, and 9. the ic50 values (mg/ml) of these compounds were in the ranges of 0.9-38. all prepared derivatives were tested against different cancer cell lines, including hela, hct 116, and mcf-7, in addition to a normal human dermal neonatal fibroblast (nhdf-neo). compound 2, designated with r = r1 = h and r2 = oac, was the most active, with ic50 values of 30.98, 22.7, and 4.12 mm against hela, hct 116, and mcf-7, respectively. other derivatives exhibited low bioactivity. this could be attributed to the use of the quinolone hydroxyl group to form a glycosidic linkage, which impedes the chelation of metal ions due to steric hindrance. in this respect, it should be stated that the presence of the 1,2,3-triazole moiety improves the activity of glycoconjugates, whereas the type of sugar fragment did not affect the activity significantly. finally, conjugates with a sugar moiety and free hydroxyl group exerted better inhibitory potential than acetylated analogs. fouda published a paper dealing with the synthesis, characterization, and cytotoxicity of new derivatives of halogenated 2-amino-4-aryl-4-pyrano[3,2-h]quinolone-3-carbonitrile (48) derivatives (scheme 12) [33] . these derivatives were prepared through interactions of various 8hydroxyquinolines (46) with α-cyanocinnamonitriles (47) . these prepared compounds were screened for potential anticancer activity against mcf-7, hct 116, hepg-2, and a549 using the mmt assay. structure-activity relationship (sar) results revealed that 6-chloroanalogues were the most active, whereas the 9-methylanaloguess were the least potent. in addition, the lipophilicity of the products increased in the presence of halogen atom substituents at positions 4, 6, and 9. the ic50 values (mg/ml) of these compounds were in the ranges of 0.9-38.2, 1.3-45.5, 0.7-44.5, and 1.23-36.7 against mcf-7, hct 116, hepg2, and a549, respectively; while the colchicine reference showed ic50 values of 6.1, 2.6, 4.6, and 3.78 mg/ml, respectively. in a similar fashion, chhabra et al. (2017) described an amberlite ira 402(oh)-mediated synthesis of novel benzothiazole-quinoline conjugates with excellent yields [34] . a synthetic procedure (scheme 13) involved a condensation reaction between the amino group (nh2) in 49 and the carbonyl group in salicylic aldehyde (50), followed by intramolecular cyclization under a these prepared compounds were screened for potential anticancer activity against mcf-7, hct 116, hepg-2, and a549 using the mmt assay. structure-activity relationship (sar) results revealed that 6-chloroanalogues were the most active, whereas the 9-methylanaloguess were the least potent. in addition, the lipophilicity of the products increased in the presence of halogen atom substituents at positions 4, 6, and 9. the ic 50 values (mg/ml) of these compounds were in the ranges of 0.9-38.2, 1.3-45.5, 0.7-44.5, and 1.23-36.7 against mcf-7, hct 116, hepg2, and a549, respectively; while the colchicine reference showed ic 50 values of 6.1, 2.6, 4.6, and 3.78 mg/ml, respectively. in a similar fashion, chhabra et al. (2017) described an amberlite ira 402(oh)-mediated synthesis of novel benzothiazole-quinoline conjugates with excellent yields [34] . a synthetic procedure (scheme 13) involved a condensation reaction between the amino group (nh 2 ) in 49 and the carbonyl group in salicylic aldehyde (50), followed by intramolecular cyclization under a microwave approach to form the benzothiazole (51) . the reaction between 51 and 5,7-dialkyl-8-hydroxyquinoline as a phenolate ion in the presence of a catalytic amount of amberlite ira and an excess amount of dibromoalkane under microwave conditions afforded the target product 52; dibromoalkanes were employed as linkers between the two fragments, 8-hydroxyquinoline and 2-benzothiazol-2-ylphenol. the prepared compounds were then subjected to a cytotoxicity study along with cisplatin (a positive control) against a panel of cancer cell lines, including hela, mcf-7, a549, and human ovarian carcinoma (a2780), using the mmt assay. most of the prepared compounds were more potent than cisplatin, with ic 50 values in the ranges of 5-19, 7-49, 10-30, and 10-38 mm against mcf-7, hela cells, a2780, and a549, respectively. in addition, the target products were 3-25-fold more selective in cancer cell lines than normal fibroblasts. molecules 2020, 25, x for peer review 12 of 26 microwave approach to form the benzothiazole (51) . the reaction between 51 and 5,7-dialkyl-8hydroxyquinoline as a phenolate ion in the presence of a catalytic amount of amberlite ira and an excess amount of dibromoalkane under microwave conditions afforded the target product 52; dibromoalkanes were employed as linkers between the two fragments, 8-hydroxyquinoline and 2benzothiazol-2-ylphenol. the prepared compounds were then subjected to a cytotoxicity study along with cisplatin (a positive control) against a panel of cancer cell lines, including hela, mcf-7, a549, and human ovarian carcinoma (a2780), using the mmt assay. most of the prepared compounds were more potent than cisplatin, with ic50 values in the ranges of 5-19, 7-49, 10-30, and 10-38 mm against mcf-7, hela cells, a2780, and a549, respectively. in addition, the target products were 3-25-fold more selective in cancer cell lines than normal fibroblasts. gayathri and coworkers prepared a novel compound (figure 4 ) bearing three quinolinone moieties in a simple procedure that involved a reaction of 3,6-bis(bromomethyl)-2-chloroquinoline and 8-hydroxyquinoline at a ratio of 1:2 in acetone (aprotic polar solvent) under reflux conditions. the target product was fully characterized by using various spectroscopic techniques and singlecrystal x-ray diffraction method. this compound was screened against mcf-7 and hela cancer cell in addition, shamsi and coworkers prepared 16 quinoline-based 1,3,4-oxadiazole-triazole derivatives (scheme 14) based on the hybrid strategy of nitrogen-containing heterocyclic scaffolds [36] . these compounds were considered to be high-impact motifs with a wide range of biological activities [37, 38] . the synthetic strategy was based on the treatment of 1 with carbonate to produce the phenolate anion, which reacts with ethyl chloroacetate under sn2 conditions to afford the corresponding intermediate. reaction of this intermediate with hydrazine produced 54, which undergoes intramolecular cyclization in the presence of carbon disulfide and the base (koh) to give compound 55 (1,3,4-oxadiazole) after acidification. the thiol group (ar-sh) in 55 is acidic and gives the ar-sanion upon treatment with a base. then, the corresponding anion reacts with propargyl bromide to afford compound 56. finally, reaction of various azide derivatives of 56 yielded the target derivative 57 through a (3 + 2) cycloaddition mechanism. scheme 13. synthesis of novel benzothiazole-quinoline derivatives. gayathri and coworkers prepared a novel compound (figure 4 ) bearing three quinolinone moieties in a simple procedure that involved a reaction of 3,6-bis(bromomethyl)-2-chloroquinoline and 8-hydroxyquinoline at a ratio of 1:2 in acetone (aprotic polar solvent) under reflux conditions. the target product was fully characterized by using various spectroscopic techniques and single-crystal x-ray diffraction method. this compound was screened against mcf-7 and hela cancer cell lines using mmt assay, giving ic 50 values of 21.02 and 27.73 mm, respectively [35] . molecules 2020, 25, x for peer review 12 of 26 microwave approach to form the benzothiazole (51) . the reaction between 51 and 5,7-dialkyl-8hydroxyquinoline as a phenolate ion in the presence of a catalytic amount of amberlite ira and an excess amount of dibromoalkane under microwave conditions afforded the target product 52; dibromoalkanes were employed as linkers between the two fragments, 8-hydroxyquinoline and 2benzothiazol-2-ylphenol. the prepared compounds were then subjected to a cytotoxicity study along with cisplatin (a positive control) against a panel of cancer cell lines, including hela, mcf-7, a549, and human ovarian carcinoma (a2780), using the mmt assay. most of the prepared compounds were more potent than cisplatin, with ic50 values in the ranges of 5-19, 7-49, 10-30, and 10-38 mm against mcf-7, hela cells, a2780, and a549, respectively. in addition, the target products were 3-25-fold more selective in cancer cell lines than normal fibroblasts. gayathri and coworkers prepared a novel compound (figure 4 ) bearing three quinolinone moieties in a simple procedure that involved a reaction of 3,6-bis(bromomethyl)-2-chloroquinoline and 8-hydroxyquinoline at a ratio of 1:2 in acetone (aprotic polar solvent) under reflux conditions. the target product was fully characterized by using various spectroscopic techniques and singlecrystal x-ray diffraction method. this compound was screened against mcf-7 and hela cancer cell lines using mmt assay, giving ic50 values of 21.02 and 27.73 mm, respectively in addition, shamsi and coworkers prepared 16 quinoline-based 1,3,4-oxadiazole-triazole derivatives (scheme 14) based on the hybrid strategy of nitrogen-containing heterocyclic scaffolds [36] . these compounds were considered to be high-impact motifs with a wide range of biological activities [37, 38] . the synthetic strategy was based on the treatment of 1 with carbonate to produce the phenolate anion, which reacts with ethyl chloroacetate under sn2 conditions to afford the corresponding intermediate. reaction of this intermediate with hydrazine produced 54, which undergoes intramolecular cyclization in the presence of carbon disulfide and the base (koh) to give compound 55 (1,3,4-oxadiazole) after acidification. the thiol group (ar-sh) in 55 is acidic and gives the ar-sanion upon treatment with a base. then, the corresponding anion reacts with propargyl bromide to afford compound 56. finally, reaction of various azide derivatives of 56 yielded the target derivative 57 through a (3 + 2) cycloaddition mechanism. in addition, shamsi and coworkers prepared 16 quinoline-based 1,3,4-oxadiazole-triazole derivatives (scheme 14) based on the hybrid strategy of nitrogen-containing heterocyclic scaffolds [36] . these compounds were considered to be high-impact motifs with a wide range of biological activities [37, 38] . the synthetic strategy was based on the treatment of 1 with carbonate to produce the phenolate anion, which reacts with ethyl chloroacetate under s n 2 conditions to afford the corresponding intermediate. reaction of this intermediate with hydrazine produced 54, which undergoes intramolecular cyclization in the presence of carbon disulfide and the base (koh) to give compound 55 (1,3,4-oxadiazole) after acidification. the thiol group (ar-sh) in 55 is acidic and gives the ar-s − anion upon treatment with a base. then, the corresponding anion reacts with propargyl bromide to afford compound 56. finally, reaction of various azide derivatives of 56 yielded the target derivative 57 through a (3 + 2) cycloaddition mechanism. the anticancer activities of all of these derivatives were examined against four different human cancel cell lines, namely human lung carcinoma (a-549), hepatocellular carcinoma (hepg2), human cervical carcinoma-hpv18 (hela), and human cervical carcinoma-hpv16 (siha), using the mmt colorimetric assay; normal cells were used as controls, whereas doxorubicin was used as the reference drug. the results indicated that the product with an o-chloro substitution on the phenyl ring was the most potent, with an ic 50 value of 5.6 mm against the a-549 cell line, which is higher than that of doxorubicin (ic 50 = 1.83 mm). interestingly, this compound was not toxic towards normal cells (up to 200 mm concentration). the anticancer activities of all of these derivatives were examined against four different human cancel cell lines, namely human lung carcinoma (a-549), hepatocellular carcinoma (hepg2), human cervical carcinoma-hpv18 (hela), and human cervical carcinoma-hpv16 (siha), using the mmt colorimetric assay; normal cells were used as controls, whereas doxorubicin was used as the reference drug. the results indicated that the product with an o-chloro substitution on the phenyl ring was the most potent, with an ic50 value of 5.6 mm against the a-549 cell line, which is higher than that of doxorubicin (ic50 = 1.83 mm). interestingly, this compound was not toxic towards normal cells (up to 200 mm concentration). a series of styrylquinolines with various substituents was prepared as shown in scheme 15 [39] . in the first step of the synthesis, the hydroxyl group in 58 was protected by conversion into the acetyl analogue 59. then, a condensation reaction between a methyl group at position 2 of protected 8hydroxyquinoline and appropriate aromatic aldehydes as carried out using microwave heating or conventional procedures [40] . finally, deprotection of the acyl group was achieved with carbonate anion-methanol or pyridine-water mixture afforded the target products 60. a series of styrylquinolines with various substituents was prepared as shown in scheme 15 [39] . in the first step of the synthesis, the hydroxyl group in 58 was protected by conversion into the acetyl analogue 59. then, a condensation reaction between a methyl group at position 2 of protected 8-hydroxyquinoline and appropriate aromatic aldehydes as carried out using microwave heating or conventional procedures [40] . finally, deprotection of the acyl group was achieved with carbonate anion-methanol or pyridine-water mixture afforded the target products 60. the anticancer activities of all of these derivatives were examined against four different human cancel cell lines, namely human lung carcinoma (a-549), hepatocellular carcinoma (hepg2), human cervical carcinoma-hpv18 (hela), and human cervical carcinoma-hpv16 (siha), using the mmt colorimetric assay; normal cells were used as controls, whereas doxorubicin was used as the reference drug. the results indicated that the product with an o-chloro substitution on the phenyl ring was the most potent, with an ic50 value of 5.6 mm against the a-549 cell line, which is higher than that of doxorubicin (ic50 = 1.83 mm). interestingly, this compound was not toxic towards normal cells (up to 200 mm concentration). a series of styrylquinolines with various substituents was prepared as shown in scheme 15 [39] . in the first step of the synthesis, the hydroxyl group in 58 was protected by conversion into the acetyl analogue 59. then, a condensation reaction between a methyl group at position 2 of protected 8hydroxyquinoline and appropriate aromatic aldehydes as carried out using microwave heating or conventional procedures [40] . finally, deprotection of the acyl group was achieved with carbonate anion-methanol or pyridine-water mixture afforded the target products 60. all prepared compounds were screened for anticancer activity against the wild-type hct 116 p53 +/+ and hct 116 p53 −/− cells and for cytotoxicity against normal cell fibroblasts. the results revealed that derivatives that have hydroxyl or acyloxy groups at position 8 of the quinolone moiety exhibit moderate activities (4.60-25.00 mm) and (2.61-25.00 mm) towards p53 +/+ and p53 −/− , respectively. analogues that were based on dichloroquinone and oxyacyl groups were the most active in this series towards p53 +/+ and p53 −/− (0. 28-13.85 [41] . their synthetic procedure involved a knoevenagel condensation between malonitrile (61) and the respective aryl aldehyde 62 to afford the corresponding arylidene-malonitrile intermediates 63, as shown in scheme 16. then, the phenolate anion attacks the β-carbon via c-7 to produce an acyclic michael adduct, which undergoes cyclization reaction (6-exo-dig) and tautomerization to afford the target product 64. all prepared derivatives in the study (along with compound ly290181 used as the standard) have been tested against various cancer cell lines, namely pancreatic carcinoma 518a, colon carcinoma cells ht-29, dld-1, hct 116, cervix carcinoma kb-v1 vbl , and mcf-7 tobo breast carcinoma cell lines, in addition to non-malignant fibroblasts. the results revealed that that these derivatives exhibit remarkable activities, with ic 50 values in nanomolar concentrations, meaning these results are even better than the activity of ly290181. two compounds designated with r = ch 3 , r 1 = r 3 = h, r 2 = r 4 = f and r = ch 3 , r 1 = r 3 = r 4 = h, r 2 = no 2 were the most active among all examined molecules. the first one had ic 50 values of 20.1 and 14 nm against mcf-7 and kb-v1 vbl , respectively. on the other hand, the second compound had an ic 50 value of 20 nm against kb-v1 vbl , which is even better than the reference. in this regard, it is worth mentioning that the mechanism of action of these compounds may be associated with tubulin polymerization interference and ros formation, in which the molecule-induced ros generation could be responsible for their cytotoxicity, since ros overproduction may induce endoplasmic reticulum stress. all prepared compounds were screened for anticancer activity against the wild-type hct 116 p53 +/+ and hct 116 p53 −/− cells and for cytotoxicity against normal cell fibroblasts. the results revealed that derivatives that have hydroxyl or acyloxy groups at position 8 of the quinolone moiety exhibit moderate activities (4.60-25.00 mm) and (2.61-25.00 mm) towards p53 +/+ and p53 −/− , respectively. analogues that were based on dichloroquinone and oxyacyl groups were the most active in this series towards p53 +/+ and p53 −/− (0. 28-13.85 [41] . their synthetic procedure involved a knoevenagel condensation between malonitrile (61) and the respective aryl aldehyde 62 to afford the corresponding arylidene-malonitrile intermediates 63, as shown in scheme 16. then, the phenolate anion attacks the β-carbon via c-7 to produce an acyclic michael adduct, which undergoes cyclization reaction (6-exo-dig) and tautomerization to afford the target product 64. all prepared derivatives in the study (along with compound ly290181 used as the standard) have been tested against various cancer cell lines, namely pancreatic carcinoma 518a, colon carcinoma cells ht-29, dld-1, hct 116, cervix carcinoma kb-v1 vbl , and mcf-7 tobo breast carcinoma cell lines, in addition to non-malignant fibroblasts. the results revealed that that these derivatives exhibit remarkable activities, with ic50 values in nanomolar concentrations, meaning these results are even better than the activity of ly290181. two compounds designated with r = ch3, r1 = r3 = h, r2 = r4 = f and r = ch3, r1 = r3 = r4 = h, r2 = no2 were the most active among all examined molecules. the first one had ic50 values of 20.1 and 14 nm against mcf-7 and kb-v1 vbl , respectively. on the other hand, the second compound had an ic50 value of 20 nm against kb-v1 vbl , which is even better than the reference. in this regard, it is worth mentioning that the mechanism of action of these compounds may be associated with tubulin polymerization interference and ros formation, in which the molecule-induced ros generation could be responsible for their cytotoxicity, since ros overproduction may induce endoplasmic reticulum stress. matrix metalloproteinases (mmps) play significant roles in cancer diseases, with mmp-2 and mmp-9 being important types among the various mmps. for instance, they could induce the release of cell membrane precursors of growth factors (e.g., epidermal growth factor receptor) ligands, which promote tumor proliferation [42, 43] . along this line, chen and colleagues described the synthesis of two series of 8-hydroxyquinolines, as shown in schemes 17 and 18 [44] . in scheme 17, the first step involved protecting the amino group in 65 with tert-butyloxycarbonyl (boc), then the free carboxylic acid group in 66 reacted with the amino groups in various substrates leading, to the formation of carboxamide 67. other steps involved deprotection to liberate the free primary amine 68 [45] , which matrix metalloproteinases (mmps) play significant roles in cancer diseases, with mmp-2 and mmp-9 being important types among the various mmps. for instance, they could induce the release of cell membrane precursors of growth factors (e.g., epidermal growth factor receptor) ligands, which promote tumor proliferation [42, 43] . along this line, chen and colleagues described the synthesis of two series of 8-hydroxyquinolines, as shown in schemes 17 and 18 [44] . in scheme 17, the first step involved protecting the amino group in 65 with tert-butyloxycarbonyl (boc), then the free carboxylic acid group in 66 reacted with the amino groups in various substrates leading, to the formation of carboxamide 67. other steps involved deprotection to liberate the free primary amine 68 [45] , which reacts with 5-chloro-8-hydroxyquinoline-7-carboaldehyde or 8-hydroxycarbaldehyde through reduction amination to yield target product 69. furthermore, in scheme 18, the phenolic hydroxyl group in 70 was protected and reaction of the primary amino group in 70 with substituted carboxylic acids afforded derivative 71. finally, deprotection of the hydroxyl group yielded the target derivative 72. molecules 2020, 25, x for peer review 15 of 26 reacts with 5-chloro-8-hydroxyquinoline-7-carboaldehyde or 8-hydroxycarbaldehyde through reduction amination to yield target product 69. furthermore, in scheme 18, the phenolic hydroxyl group in 70 was protected and reaction of the primary amino group in 70 with substituted carboxylic acids afforded derivative 71. finally, deprotection of the hydroxyl group yielded the target derivative 72. ho all of these derivatives were screened as potential mmp-2/9 inhibitors. the results revealed that compounds (of series 1) that have substituents at c-7 on the quinolone moiety showed ic50 values (mm) in the range of 0.81-10, while for those with substituents at c-5, the ic50 values ranged from 5.7 to 10. on the other hand, derivatives belonging to series 2 showed ic50 values in the range of 6.5-10 against mmp-2. as for mmp-9, using the same sequence, the ic50 values (mm) were in the ranges of 1.3-10, 5.1-10, and ˃10. some selected compounds (those with substituents at c-7) were further screened against a panel of cancer cell lines (hl60, k562, kg1, a549, pc-3, and mcf-7), along with human umbilical vein endothelial cells. the results indicated that most of the tested compounds exhibited good bioactivity, with ic50 values in the range of 0.69-22 mm. finally, the positive control, all of these derivatives were screened as potential mmp-2/9 inhibitors. the results revealed that compounds (of series 1) that have substituents at c-7 on the quinolone moiety showed ic50 values (mm) in the range of 0.81-10, while for those with substituents at c-5, the ic50 values ranged from 5.7 to 10. on the other hand, derivatives belonging to series 2 showed ic50 values in the range of 6.5-10 against mmp-2. as for mmp-9, using the same sequence, the ic50 values (mm) were in the ranges of 1.3-10, 5.1-10, and ˃10. some selected compounds (those with substituents at c-7) were further screened against a panel of cancer cell lines (hl60, k562, kg1, a549, pc-3, and mcf-7), along with human umbilical vein endothelial cells. the results indicated that most of the tested compounds exhibited good bioactivity, with ic50 values in the range of 0.69-22 mm. finally, the positive control, all of these derivatives were screened as potential mmp-2/9 inhibitors. the results revealed that compounds (of series 1) that have substituents at c-7 on the quinolone moiety showed ic 50 values (mm) in the range of 0.81-10, while for those with substituents at c-5, the ic 50 values ranged from 5.7 to 10. on the other hand, derivatives belonging to series 2 showed ic 50 values in the range of 6.5-10 against mmp-2. as for mmp-9, using the same sequence, the ic 50 values (mm) were in the ranges of 1.3-10, 5.1-10, and >10. some selected compounds (those with substituents at c-7) were further screened against a panel of cancer cell lines (hl60, k562, kg1, a549, pc-3, and mcf-7), along with human umbilical vein endothelial cells. the results indicated that most of the tested compounds exhibited good bioactivity, with ic 50 values in the range of 0.69-22 mm. finally, the positive control, the hydroxamate-based mmp inhibitor nngh [46] , showed ic 50 values of 29-187 mm for antiproliferation activities against various cancer cell lines, and against mmp-2 and mmp-9 showed values of 0.0091 and 0.0088 mm, respectively. ökten and coworkers described the synthesis of 5,7-dibromo-8-hydroxyquinoline [47] in excellent yield via reaction of 8-hydroxyquinoline with two equivalents of bromine in chloroform. the target molecule exhibited ic 50 values (mg/ml) of 5.8, 17.6, 18.7, 5.4, 16.5, and >1000 against a549, fl, hela, ht29, mcf7, and hep3b, respectively. from all of these studies, one can see the importance of the 8-hq moiety in potential anticancer drugs. in addition, some of the prepared compounds could be leads towards the development of potent and safe drugs. however, more work is required in this category, which could involve the use of animals and possibly human subjects to evaluate the efficacy and safety profiles of the prepared compounds. alzheimer's disease (ad), characterized by a loss of cognitive ability and severe behavioral irregularities, is a chronic neurodegenerative disorder. it is most common among the elderly, and can be described as an irreversible brain disorder that breaks down memory and reduces the ability of a patient to carry out simple mental and cognitive functions, such as comprehension, solving simple problems, and trivial calculations. this disease is becoming a universal health problem, and it can eventually lead to death [48] . statistics indicate the presence of approximately 2.5 to 4.0 million alzheimer's disease patients in the united states, and 17 and 25 million worldwide [49] . published research findings indicate that cholinergic dysfunction could be associated with selective and irreversible deficiency of the neurotransmitter acetylcholine, which is controlled by hydrolysis of acetylcholine via acetylcholinestrase (ache) and butyrylcholinestrase (bche). additionally, it was suggested that ache predominates in a healthy brain, whereas bche is considered to play a minor role in regulating the brain's ach levels [49] . the approved prescribed commercial drugs for the treatment of ad, which provide slight improvements in memory, include donepezil, rivastigmine, and others; their action is based on the inhibition of acetylcholinesterase. it is also worth mentioning that other factors contribute to ad, such as β-amyloid (a β) deposits and oxidative stress. in this respect, several studies have shown that levels of redox-active metal ions, including cu 2+ and zn 2+ , are observed in the brains of ad patients [50] . these metal ions can interact with β-amyloid peptides to form insoluble plaques [51, 52] . in the search for potent buche and ache inhibitors, hirbod et al. (2017) designed and prepared eight novel compounds incorporating coumarin and 8-hydroxyquinoline moieties (73), as shown in the [53] . these researchers used various dibromoalkanes (n = 3-5) as cross-linkers between 8-hydroxyquinoline and coumarin rings in the presence of an aprotic solvent (n,n-dimethylformamide). in addition, the activity levels of these prepared compounds were evaluated against buche and ache using ellman's method. the results demonstrated that some of the prepared compounds exhibited potent ache and buche inhibition activities, with half-maximal inhibitory concentration (ic 50 (74 and 75) , as shown in figure 5 [54] . the target compounds were prepared by chloromethylation of 8-hq to give 5-chloromethyl-8-hydroxyquinoline. then, the former compound was reacted with tert-butylpiperazine-1-carboxylate followed by trifluoroacetic acid to remove the protected boc group. finally, the resulting compound was reacted with the appropriate cinnamic or hydroxycinnamic acids, using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (edc). in this context, β-amyloid (aβ) significantly contributed to the progression of alzheimer's disease (ad), where elevated levels of aβ have been detected in the brains of ad patients. moreover, aβ a aggregation can be clearly observed in the presence of cu 2+ , zn 2+ , and fe 2+ ions, since these ions can readily bind to aβ through some of its specific residues. in addition, aβ can aggregate by itself. th prepared target compounds were tested for their inhibition of aβ aggregation using the thioflavon t-binding assay [55, 56] . furthermore, chelating studies of cu 2+ , zn 2+ , fe 3+ , and fe 2+ were conducted using the former prepared derivatives by means of a uv-vis spectrophotometer. the results revealed that the compound designated with r 1 = h, r 2 , r 3 = och 3 showed the maximum percentage inhibition of aβ 1→42 aggregation of 65.82% with an ic 50 of 5.64 mm compared to resveratrol, which showed corresponding values of 51.74% and 12.43 mm. in addition, the previous compound was selected as a representative to examine its metal chelation behavior; it exhibited significant activity in this context, producing even better results than clioquinol. molecules 2020, 25 [57] . synthesis of these compounds involved protection of the phenolic group in 76 using boc group to allow the reaction of the primary aromatic amine in 77 with substituted benzoyl chlorides in the presence of triethylamine (tea) as the base and catalyst to form the carboxamide group 78. in the final step, deprotection of the boc group was accomplished with hydrogen chloride to afford the desired products as salt 79. regarding scheme 20, the phenoxide anion in 80 was formed in situ by reaction of the phenolic group with potassium carbonate (base), which then reacts with benzyl bromide. the methyl group in 81 was then subjected to pinnick oxidation using seo2 to afford the corresponding acid 82. reaction of the carboxylic acid group in 82 with thionyl chloride and then with 3-(cyclopentyloxy)-4-methoxyaniline or 3,4-dimethoxyaniline afforded 83 upon removal of bn with hydrogen gas in the presence of the palladium catalyst yielded the desired product 84. on the other hand, synthesis of compound 87 was achieved by converting 1 into tert-butyldimethylsilyl (tbs)-protected 2-aminoquinolin-8-ol (85). this process was carried out by oxidation of the starting material using m-chloroperbenzoic acid (mcpba) to form n-oxide, which was subsequently followed by refluxing with dimethylsulfate, treatment with nh4oh, and finally protection with tert-butyldimethylsilyl chloride (tbscl). the obtained derivative 86 was treated with the corresponding benzoyl chlorides, then went through the deprotection process using tetrabutylammoniumfluoride (tbaf) to afford the phenolic group in the target derivative 87 (scheme 21). compounds 79, 84, and 87 are considered hybrids of clioquinol-rolipram and roflumilast as multitarget-directed ligands for the treatment of ad in terms of inhibition of phosphodiesterase 4d (pde4d), the oxygen radical absorbance capacity (orac) value, and the experimental potential of the blood-brain barrier (bbb) permeability (pe) of the selected compounds using parallel artificial membrane permeation assay (pampa). in this respect, pde4d is involved in the process of longterm potentiation and memory consolidation. one of the derivatives of 79, for which x = h, r 1 = cf2h, [57] . synthesis of these compounds involved protection of the phenolic group in 76 using boc group to allow the reaction of the primary aromatic amine in 77 with substituted benzoyl chlorides in the presence of triethylamine (tea) as the base and catalyst to form the carboxamide group 78. in the final step, deprotection of the boc group was accomplished with hydrogen chloride to afford the desired products as salt 79. regarding scheme 20, the phenoxide anion in 80 was formed in situ by reaction of the phenolic group with potassium carbonate (base), which then reacts with benzyl bromide. the methyl group in 81 was then subjected to pinnick oxidation using seo 2 to afford the corresponding acid 82. reaction of the carboxylic acid group in 82 with thionyl chloride and then with 3-(cyclopentyloxy)-4-methoxyaniline or 3,4-dimethoxyaniline afforded 83 upon removal of bn with hydrogen gas in the presence of the palladium catalyst yielded the desired product 84. on the other hand, synthesis of compound 87 was achieved by converting 1 into tert-butyldimethylsilyl (tbs)-protected 2-aminoquinolin-8-ol (85). this process was carried out by oxidation of the starting material using m-chloroperbenzoic acid (mcpba) to form n-oxide, which was subsequently followed by refluxing with dimethylsulfate, treatment with nh 4 oh, and finally protection with tert-butyldimethylsilyl chloride (tbscl). the obtained derivative 86 was treated with the corresponding benzoyl chlorides, then went through the deprotection process using tetrabutylammoniumfluoride (tbaf) to afford the phenolic group in the target derivative 87 (scheme 21). during ad [60] . the pe values of selected compounds were evaluated using pampa. the results indicated that a derivative of 87 with r 1 = ch3 and r 2 = cyclopentylmethyl exhibited a maximum value of pe 16.41 (± 0.44) × 10 6 cm s -1 , whereas other tested compounds showed values higher than 4.7 × 10 6 cm s -1 , indicating that these compounds may cross the bbb. the pe values for rolipram, roflumilast, and clioquinol were evaluated as (18.87 ± 0.57), (9.22 ± 0.62), and (5.20 ± 0.33) x 10 6 cm s -1 , respectively. during ad [60] . the pe values of selected compounds were evaluated using pampa. the results indicated that a derivative of 87 with r 1 = ch3 and r 2 = cyclopentylmethyl exhibited a maximum value of pe 16.41 (± 0.44) × 10 6 cm s -1 , whereas other tested compounds showed values higher than 4.7 × 10 6 cm s -1 , indicating that these compounds may cross the bbb. the pe values for rolipram, roflumilast, and clioquinol were evaluated as (18.87 ± 0.57), (9.22 ± 0.62), and (5.20 ± 0.33) x 10 6 cm s -1 , respectively. figure 6 [61] . compounds 88 and 89 were prepared from 8-hq by reaction first with formaldehyde in the presence of hydrogen chloride, followed by reaction with triethylphosphite to afford diethyl ((8-hydroxyquinolin-5-yl)methyl)phosphonate [56] . in this reaction, the phenolic group was protected via reaction with chloro(methoxy)methane to yield diethyl ((8-(methoxymethoxy)quinolin-5-yl)methyl)-phosphonate. subsequent reaction of the last compound with various 2-nitrobenzaldehydes in the presence of sodium hydride yielded derivatives of 8-(methoxymethoxy)-5-(2-nitrostyryl)quinolone. reductive cyclization of 2-nitrostyrenes with carbon monoxide followed by removal of the protecting group (methoxymethane) by hydrochloride solution led to the formation of the final product. for compound 89, diethyl ((7-chloro-8compounds 79, 84, and 87 are considered hybrids of clioquinol-rolipram and roflumilast as multitarget-directed ligands for the treatment of ad in terms of inhibition of phosphodiesterase 4d (pde4d), the oxygen radical absorbance capacity (orac) value, and the experimental potential of the blood-brain barrier (bbb) permeability (pe) of the selected compounds using parallel artificial membrane permeation assay (pampa). in this respect, pde4d is involved in the process of long-term potentiation and memory consolidation. one of the derivatives of 79, for which x = h, r 1 = cf 2 h, r 2 = cyclopentylethyl, exhibited an ic 50 of 0.399 mm against pde4d compared to rolipram as the reference compound (ic 50 0.621 mm), whereas the derivative showing x = h, r 1 = cyclopentylmethyl of family 84 exhibited the highest value among all tested compounds in the orac assay (its value is 1.98 expressed as trolox equivalents). in this respect, the orac value of antioxidant activities increases the ability of a given compound as the antioxidant becomes better [58] . clioquinol, rolipram, and roflumilast showed values of 0.60, 0.070, and 0.067, respectively. oxidative stress has a major effect in the production of excess free radicals, which lead to cell death and cytosceletal damage in ad [59] . finally, the bbb has a major role in the generation of chronic brain inflammation during ad [60] . the pe values of selected compounds were evaluated using pampa. the results indicated that a derivative of 87 with r 1 = ch 3 and r 2 = cyclopentylmethyl exhibited a maximum value of pe 16.41 (±0.44) × 10 6 cm s −1 , whereas other tested compounds showed values higher than 4.7 × 10 6 cm s −1 , indicating that these compounds may cross the bbb. the pe values for rolipram, roflumilast, and clioquinol were evaluated as (18.87 ± 0.57), (9.22 ± 0.62), and (5.20 ± 0.33) × 10 6 cm s −1 , respectively. an earlier paper by wang et al. (2018) described the synthesis of new 8-hydroxyquinoline derivatives, as shown in figure 6 [61] . compounds 88 and 89 were prepared from 8-hq by reaction first with formaldehyde in the presence of hydrogen chloride, followed by reaction with triethylphosphite to afford diethyl ((8-hydroxyquinolin-5-yl)methyl)phosphonate [56] . in this reaction, the phenolic group was protected via reaction with chloro (methoxy)methane to yield diethyl ((8-(methoxymethoxy) quinolin-5-yl)methyl)-phosphonate. subsequent reaction of the last compound with various 2-nitrob enzaldehydes in the presence of sodium hydride yielded derivatives of 8-(methoxymethoxy)-5-(2-nitro styryl)quinolone. reductive cyclization of 2-nitrostyrenes with carbon monoxide followed by removal of the protecting group (methoxymethane) by hydrochloride solution led to the formation of the final product. for compound 89, diethyl ((7-chloro-8-hydroxyquinolin-5-yl)methyl)-phosphonate was prepared by reacting diethyl ((8-hydroxyquinolin-5-yl)methyl)phosphonate with sodium hypochlorite, followed by the same previous steps. on the other hand, compound 91 was prepared through a series of steps that involved reacting 2-methyl-8-hydroxyqunolines 90 with acetic anhydride, then with 2-nitrobenzaldehydes, followed by reductive cyclization of 2-nitrostyerenes in the presence of the palladium (ii) acetate catalyst under carbon monoxide gas, and finally with a base (carbonate or methoxide ions, depending on the nature of x). compounds 88, 89, and 91 were tested against the orac assay, bbb permeability assay, and inhibition activity towards amyloid beta (aβ) self-induced aggregation. the results revealed that compounds 88 (r = oh), 89 (x = h, r 1 = oh, r 2 = h), and 91 (x = h, r 1 = oh, r 2 = ch 3 ) exhibited the highest activities among all prepared compounds (6.6, 5.3, 5.9, and 5.4, respectively). the presence of the phenolic hydroxyl group at c-5 of the indole moiety enhances the activity. on the other hand, the presence of a chlorine atom in compound 89 lowers the activity compared to a hydrogen. the reference standards, including clioquinol, melatonin, and a mixture of clioquinol and melatonin, exhibit the values of 0.5, 2.4, and 2.9, respectively. this test was performed based on a fluorescein (orac-fl) method with a trolox as the internal standard. similarly, permeation of the bbb is considered an important parameter for potential central nervous system (cns) candidates; this assay was accomplished using the parma method. the results showed that most of the target products could effectively permeate the bbb through passive diffusion. two compounds of series 91, designated as x = h, r 1 = oh, r 2 = h and x = h, r 1 = oh, r 2 = och 3 , showed higher bbb permeability activity (pe values 14.8 and 12.1, respectively) compared to other derivatives that have a hydrogen atom instead of the phenolic hydroxyl group. in contrast, compounds 88 and 89, bearing the indole moiety at position 5 of the quinolone scaffold, gave pe values of 9.1 and 6.8, respectively, even in the presence of a phenolic hydroxyl group. aβ represents the major component of amyloid plaques found in the brains of alzheimer's patients [62] . inhibition of aβ self-induced aggregation for the prepared 8-hydroxyquinoline-indole derivatives was examined using thioflavin fluorescence. one of the derivatives of 91, for which x = h, r 1 = oh, r 2 = h, caused 51.2% percent inhibition, which was the highest percentage among the prepared compounds. on the other hand, compounds 88 and 89 caused 57.2% and 68.7% inhibition, respectively; whereas clioquinol, curcumin, and resveratrol showed 1.9%, 36.7%, and 42.1% inhibition, respectively. in a recent publication, prati and coworkers [63] described the synthesis of a new series of 8-hydroxyquinoline derivatives (94) for which the products possess structural features of two commercial drugs, namely donepezil and clioquinol. depicted in scheme 22 are the steps involved in the synthesis of these compounds. in a recent publication, prati and coworkers [63] this synthesis was a multicomponent mannich reaction that involved a mixture containing piperazine (92), paraformaldehyde, and 8-hq or its 5-chloroanalogue under a microwave-assisted procedure to afford 7-(piperazin-1-ylmethyl)-8-hydroxyquinolines (93). this synthon was then reacted with various benzyl chlorides in dmf. compound 94 and its derivatives were assayed for potential inhibitory activity towards human anti-hache and anti-hbche. the results indicated that at a concentration of 40 mm, all derivatives exhibited inhibition, with values ranging from 9.0 to 63.8% and 49.2 to 89.1% for 5-chloro-8-hydroxyquinoline and 8-hydroxyquinoline derivatives, respectively, against hbche. however, these compounds were inactive or showed very weak inhibition activity against hache, suggesting selectivity of the target products towards hbche. in addition, these results highlighted the effect of the chlorine atom at position 5 of the 8hydroxyquinoline moiety on the activity compared to the hydrogen atom. the chemical references this synthesis was a multicomponent mannich reaction that involved a mixture containing piperazine (92), paraformaldehyde, and 8-hq or its 5-chloroanalogue under a microwave-assisted procedure to afford 7-(piperazin-1-ylmethyl)-8-hydroxyquinolines (93). this synthon was then reacted with various benzyl chlorides in dmf. compound 94 and its derivatives were assayed for potential inhibitory activity towards human anti-hache and anti-hbche. the results indicated that at a concentration of 40 mm, all derivatives exhibited inhibition, with values ranging from 9.0 to 63.8% and 49.2 to 89.1% for 5-chloro-8-hydroxyquinoline and 8-hydroxyquinoline derivatives, respectively, against hbche. however, these compounds were inactive or showed very weak inhibition activity against hache, suggesting selectivity of the target products towards hbche. in addition, these results highlighted the effect of the chlorine atom at position 5 of the 8-hydroxyquinoline moiety on the activity compared to the hydrogen atom. the chemical references donepezil, tacrine, and galantamine exhibited inhibition towards hbche, with values of 84.3, >90, and 65.8%, respectively. on the other hand, the inhibition activity of compound 10 and its derivatives towards the aβ 42 antiaggregating property was evaluated. the obtained results demonstrated that the inhibition potencies of all derivatives ranged from 19.1 to 65.0% at the concentration of 50 mm; both series (x = h, cl) had close activity rates. in addition, the metal chelating ability of the selected compounds was examined using cu 2+ and zn 2+ in phosphate buffer solution (ph 7.4). spectroscopic data showed that there is a bathochromic shift of about 18 nm from the original band (243 nm) upon complex formation; as the metal ion concentration increases (1.56 to 50 mm), the intensity of the absorption band also increases. finally, all derivatives showed antioxidant activity, whereby some prepared compounds exhibited higher activity than trolox. raj and padhi reported that the condensation of 8-hydroxyquinoline-2-carbaldehyde (95) with aromatic diamines (96) afforded quinoline-based benzimidazole (97) followed by intracyclization reaction to produce derivatives of 100. with aliphatic diamines (98), compound 95 produced bis-imines (99) without undergoing intracyclization reaction, as shown in scheme 23 [64] . products of these reactions have been well-characterized using various techniques, including ft-ir, nmr, ms, and single-crystal x-ray diffraction method. in the first step of both reactions, one equivalent of 8-hydroxyquinoline-2-carbaldehyde underwent a condensation reaction with one equivalent of primary amine to form the mono-imine product (schiff bases). however, in the second step and with the presence of aromatic amine, an intramolecular ring cyclization occurred, where the resulting precursor reacts further with the second equivalent of 8-hydroxyquinoline-2-carbaldehyde, followed by migration of hydride to afford compound 100. in the case of an aliphatic amine, the second step represents a second condensation reaction with another molecule of 8-hydroxyquinoline-2-carbaldehyde to give the final product 99. in a recent publication, prati and coworkers [63] described the synthesis of a new series of 8hydroxyquinoline derivatives (94) for which the products possess structural features of two commercial drugs, namely donepezil and clioquinol. depicted in scheme 22 are the steps involved in the synthesis of these compounds. this synthesis was a multicomponent mannich reaction that involved a mixture containing piperazine (92), paraformaldehyde, and 8-hq or its 5-chloroanalogue under a microwave-assisted procedure to afford 7-(piperazin-1-ylmethyl)-8-hydroxyquinolines (93). this synthon was then reacted with various benzyl chlorides in dmf. compound 94 and its derivatives were assayed for potential inhibitory activity towards human anti-hache and anti-hbche. the results indicated that at a concentration of 40 mm, all derivatives exhibited inhibition, with values ranging from 9.0 to 63.8% and 49.2 to 89.1% for 5-chloro-8-hydroxyquinoline and 8-hydroxyquinoline derivatives, respectively, against hbche. however, these compounds were inactive or showed very weak inhibition activity against hache, suggesting selectivity of the target products towards hbche. in addition, these results highlighted the effect of the chlorine atom at position 5 of the 8hydroxyquinoline moiety on the activity compared to the hydrogen atom. the chemical references scheme 23. synthesis of new derivatives of 8-hydroxyquinolie-based benzimidazole. on the other hand, kong et al. (2017) prepared novel barbituroquinoline derivatives 106 and 107 in a one-pot procedure by combining three components in water, namely 1, 2-thiobarbituric acid (104), and aldehyde (isatin) 105 [67] , as shown in scheme 25. this reaction was conducted under mild experimental conditions and without a catalyst. nitriles or acetonitrile in aqueous potassium hydroxide solution yielded 1,2,4-triazole-based quinolone (103 on the other hand, kong et al. (2017) prepared novel barbituroquinoline derivatives 106 and 107 in a one-pot procedure by combining three components in water, namely 1, 2-thiobarbituric acid (104), and aldehyde (isatin) 105 [67] , as shown in scheme 25. this reaction was conducted under mild experimental conditions and without a catalyst. the 8-hydroxyquinoline moiety can act as a building block for various pharmacologically active scaffolds. in the present work, we have reviewed the recent literature pertaining to the synthesis and bioactivity of numerous 8-hq derivatives as anticancer, antiviral, antimicrobial, antibacterial, antifungal, and anticancer agents. the results obtained from this review highlight the importance of numerous derivatives of 8-hq as possible chemotherapeutic agents and as possible leads towards the development of new drugs to treat various diseases, including cancer. we hope that data presented in this review could help researchers in the fields of medicinal chemistry and pharmacology in designing new active compounds and in the modification of existing compounds in the search for new drug leads. the development of drugs, either natural or synthetic, is gaining popularity in the fight against diseases, such as cardiovascular disorders, cancer insurgence, and immune dysfunction. there are certain nuclei such as 8-hq that are important building blocks in the medicinal arena. therefore, new synthetic methods for bioactive 8-hq derivatives should be pursued. in this respect, more biological testing, including in vivo studies, should accompany these syntheses. studies should also involve different pharmacokinetic parameters related to the safety profiles of potent derivatives. in this review, we have shown different synthetic strategies for pharmaceutically important chemicals that incorporate the 8-hq moiety. these compounds exhibited a wide range of biological activities and could be used as therapeutic agents against different diseases, including cancer. some of these compounds could be envisioned as leads in the development of drugs. compound 101 then reacted with alkenes or alkynes containing electron-withdrawing substituents under the mechanism of 1,3-dipolarcycloaddition and in the presence of a base (k 2 co 3 ) to afford 102. on the other hand, the reaction of 101 with aromatic nitriles or acetonitrile in aqueous potassium hydroxide solution yielded 1,2,4-triazole-based quinolone (103) 8-hydroxyquinoline and its derivatives: synthesis and applications immiscible polymers in double spin-coated electroluminescent devices containing phenyl-substituted tris (8-hydroxyquinoline) aluminum derivatives soluble in a host polymer 8-hydroxyquinolines in medicinal chemistry: a structural perspective 8-hydroxyquinoline: a privileged structure with a broad-ranging pharmacological potential synthesis, characterization, and anti-corrosion properties of an 8-hydroxyquinoline derivative synthesis and characterization of 8-hydroxyquinoline complexes of tin (iv) and their application in organic light emitting diode antiviral activity of novel quinoline derivatives against dengue virus serotype 2 8-hydroxyquinoline-2-carboxanilides as antiviral agents against avian influenza virus synthesis and antibacterial activity of 3-benzylamide derivatives as ftsz inhibitors chemoselective synthesis of 5-amino-7-bromoquinolin-8-yl sulfonate derivatives and their antimicrobial evaluation synthesis, antibacterial properties and bioinformatics computational analyses of novel 8-hydroxyquinoline derivatives synthesis and biological evaluation of quinoline derivatives as a novel class of broad-spectrum antibacterial agents in vitro activities of a new fluoroquinolone derivative highly active against chlamydia trachomatis antifungal activity of umbelliferone derivatives: synthesis and structure-activity relationships synthesis of some novel 3, 4, 5-trisubstituted triazole derivatives bearing quinoline ring and evaluation of their antimicrobial activity a comprehensive review on the chemotherapeutic potential of piceatannol for cancer treatment, with mechanistic insights a novel potent nicotinamide phosphoribosyltransferase inhibitor synthesized via click chemistry synthesis and structure-activity relationships study of a-aminophosphonate derivatives containing a quinoline moiety an extremely stable and orthogonal dna base pair with a simplified three-carbon backbone synthesis and investigation of antibacterial and antioxidants properties of some new 5-subsituted-8-hydroxyquinoline derivatives synthesis, spectroscopic characterization, x-ray analysis, and dft-hf calculations of 5-ethoxymethyl-8-hydroxyquinoline synthesis and antimicrobial activities of sulfonohydrazide-substituted 8-hydroxyquinoline derivative and its oxinates bioconjugation via azide-staudinger ligation: an overview synthesis and biological evaluation of 8-hydroxyquinoline-hydrazones for anti-hiv-1 and anticancer potential design, synthesis and biological evaluation of 2-substituted quinolines as potential antileishmanial agents design, synthesis and biological evaluation of 1, 3, 6-trisubstituted b-carboline derivatives for cytotoxic and anti-leishmanial potential co-delivery of docetaxel and gemcitabine by anacardic acid modified self-assembled albumin nanoparticles for effective breast cancer management novel gemcitabine conjugated albumin nanoparticles: a potential strategy to enhance drug efficacy in pancreatic cancer treatment synthesis of 8-hydroxyquinoline glycoconjugates and preliminary assay of their b1,4-galt inhibitory and anti-cancer properties synthesis and characterization of a new cationic galactolipid with carbamate for gene delivery click'assembly of glycoclusters and discovery of a trehalose analogue that retards aβ40 aggregation and inhibits aβ40-induced neurotoxicity chemoselective ligation of maleimidosugars to peptides/protein for the preparation of neoglycopeptides/neoglycoprotein halogenated 2-amino-4h-pyrano [3,2-h] quinoline-3-carbonitriles as antitumor agents and structure-activity relationships of the 4-, 6-, and 9-positions amberlite ira 402 (oh) mediated green synthesis of novel benzothiazole-quinoline conjugates as cancer theranostics comparative theoretical and experimental study on novel tri-quinoline system and its anticancer studies synthesis, anticancer evaluation and dna-binding spectroscopic insights of quinoline-based 1, 3, 4-oxadiazole-1, 2, 3-triazole conjugates synthesis and anti-breast cancer activities of substituted quinolines design, synthesis and biological evaluation of new 4-(4-substituted-anilino) quinoline derivatives as anticancer agents the synthesis and anticancer activity of 2-styrylquinoline derivatives. a p53 independent mechanism of action an efficient microwave-assisted synthesis of structurally diverse styrylquinolines new pyranoquinoline derivatives as vascular-disrupting anticancer agents matrix metalloproteinase-7 degrades all insulin-like growth factor binding proteins and facilitates insulin-like growth factor bioavailability review on epidermal growth factor receptor (egfr) structure, signaling pathways, interactions, and recent updates of egfr inhibitors design, synthesis and preliminary bioactivity evaluations of 8-hydroxyquinoline derivatives as matrix metalloproteinase (mmp) inhibitors synthesis of tetracyclic pyrrolidine/isoxazolidine fused pyrano [3,2-h] quinolines via intramolecular 1,3-dipolar cycloaddition in ionic liquid discovery of cgs 27023a, a non-peptidic, potent, and orally active stromelysin inhibitor that blocks cartilage degradation in rabbits quinoline-based promising anticancer and antibacterial agents, and some metabolic enzyme inhibitors acetylcholinesterase inhibition by flavonoids from agrimonia pilosa coumarin derivatives as acetyl-and butyrylcholinestrase inhibitors: an in vitro, molecular docking, and molecular dynamics simulations study cholinesterase inhibitors and beyond pet imaging of copper trafficking in a mouse model of alzheimer disease nanoprobing of the effect of cu 2+ cations on misfolding, interaction and aggregation of amyloid b peptide coumarin derivatives bearing benzoheterocycle moiety: synthesis, cholinesterase inhibitory, and docking simulation study novel 8-hydroxyquinoline derivatives targeting b-amyloid aggregation, metal chelation and oxidative stress against alzheimer's disease design, synthesis, and evaluation of multitarget-directed resveratrol derivatives for the treatment of alzheimer's disease design, synthesis, and evaluation of orally available clioquinol-moracin m hybrids as multitarget-directed ligands for cognitive improvement in a rat model of neurodegeneration in alzheimer's disease synthesis and evaluation of clioquinol-rolipram/roflumilast hybrids as multitarget-directed ligands for the treatment of alzheimer's disease profiling donepezil template into multipotent hybrids with antioxidant properties antioxidant capacity in the lipophilic fraction of alzheimer's brain tissues inflammatory events at blood-brain barrier in neuroinflammatory and neurodegenerative disorders: implications for clinical disease design, synthesis, and evaluation of orally bioavailable quinoline-indole derivatives as innovative multitarget-directed ligands: promotion of cell proliferation in the adult murine hippocampus for the treatment of alzheimer's disease the amyloid beta peptide: a chemist's perspective. role in alzheimer's and fibrillization novel 8-hydroxyquinoline derivatives as multitarget compounds for the treatment of alzheimer's disease synthesis, characterization, and structure of quinoline-based benzimidazole derivatives synthesis of pyrazolo-and [1,2,4] triazolo-[1,5-a] quinolin-9-ols by cycloaddition to 8-hydroxyquinoline n-imide o-mesitylenesulfonylhydroxylamine and related compounds-powerful aminating reagents convenient one-pot synthesis of thiobarbituro-quinoline derivatives via catalyst-free multicomponent reactions in water this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license funding: this research received no external funding. the authors declare no conflict of interest. key: cord-338727-1kodz527 authors: ilinskaya, o. n.; mahmud, r. shah title: ribonucleases as antiviral agents date: 2014-10-11 journal: mol biol doi: 10.1134/s0026893314040050 sha: doc_id: 338727 cord_uid: 1kodz527 many ribonucleases (rnases) are able to inhibit the reproduction of viruses in infected cell cultures and laboratory animals, but the molecular mechanisms of their antiviral activity remain unclear. the review discusses the well-known rnases that possess established antiviral effects, including both intracellular rnases (rnase l, mcpip1 protein, and eosinophil-associated rnases) and exogenous rnases (rnase a, bs-rnase, onconase, binase, and synthetic rnases). attention is paid to two important, but not always obligatory, aspects of molecules of rnases that have antiviral properties, i.e., catalytic activity and ability to dimerize. the hypothetic scheme of virus elimination by exogenous rnases that reflects possible types of interaction of viruses and rnases with a cell is proposed. the evidence for rnases as classical components of immune defense and thus perspective agents for the development of new antiviral therapeutics is proposed. ribonucleases (rnases) that catalyze rna cleav age play a key role in the regulation of vital processes in any organism, ranging from virus to human. with out the reactions of rna degradation, the maturation of mrna and noncoding rna, the functioning of global systems of rna interference, and the epige netic regulation of gene expression, as well as pro cesses of cell growth and differentiation, apoptosis induction, and protection against viral infection, are not possible. there are approximately 20 exo and endonucleases of various nucleotide sequence and structure specificity in a cell [1] . along with intracel lular rnases, there are rnases that may be secreted into cultural or tissue fluid. biological effects of exog enous rnases are of particular interest. the control of blood vessel growth, toxicity against tumor cells, and antiviral activity are all properties of rnases that may potentially be utilized in medicine and define the cur rent hot points in studies focused on these enzymes. in the review, we consider the best known rnase that possesses antiviral effects. molecular structures of these rnases are presented in fig. 1 ; obviously, they are not characterized by a significant homology. therefore, the structural similarity of the catalytically active proteins is not a determining feature for their antiviral effects. in the 1960s, a group of scientists under the guid ance of prof. p. i. salganik at the institute of cytology and genetics (siberian branch, russian academy of sciences) demonstrated that increased activity of rna cleaving enzymes is observed in the blood and cerebrospinal fluid of tick borne encephalitis patients [2] . rnases were hypothesized to be directly involved in biological mechanisms of antivirus protection. the activation of intracellular rnases in the presence of antiviral preparations was later detected in plants [3] . in particular, transgenic tobacco plants with increased activity of intracellular zinnia elegans ribonuclease zrnaseii possessed high stability against the tobacco mosaic virus [4] . bacterial endoribonucleases specific to certain nucleotide sequences, e.g., the rnase toxn, provide for the phage stability of the population, inducing death of cells due to cleavage of phage and cel lular rna [5] . cleavage of trna by an anticodon nuclease prrc of escherichia coli is a mechanism of bacteria protection from infection with t4 phage [6] . the involvement of rnases in the protection of cells and the organism from viruses has been con firmed by ample evidence. a considerable body of data has been accumulated and allows one to consider rnases to be not only components of immune defense, but also the basis for the development of new antiviral preparations. the antiviral effect of rnases is best studied in the case of a signaling system involving rnase l, which mediates the effect of interferon induced by viral infection. the key enzyme of the system is 2',5' oli goadenylate synthetase polymerizing atp with for mation of rnase l activator, 2',5' oligoadenylate, of the general formula ppp2',5' a n , where n = 2-10 ade nylate residues. rnase l mechanism of action is well studied, i.e., the active form of rnase l forms a dimer with endoribonuleolytic activity against both viral and cellular rna [7, 8] . products of rna cleavage less than 200 nucleotide long are recognized by protein factors rig i and mda5. therefore, the formation of rna fragments enhanced by rnase l, followed by their interaction with rig i and mda5, activates transcription factor nf κb and triggers transcription of interferon β gene, which prevents virus replication and stimulates the growth of immune system cells [9] . however, the system may not completely protect cells from virus. in enteroviruses of group c, a phylogenet ically conserved rna structure resistant to cleavage by rnase l and inhibiting the activity of its endoribo nuclease domain has been found inside an open read ing frame [10] . a neurotropic theiler's picornavirus inducing chronic infection of central nervous system and demyelination of nervous tissue produces a spe cies specific helper protein l* that inhibits rnase l through interaction with its ankyrin domain [11] . these viruses possess mechanisms that provide for their resistance to rnase l, because they may block either its activity or ability for dimer formation. inter estingly, dimerization contributes to the antiviral activity of rnases l, along with the catalytic activity, which is required for viral rna cleavage a priori. zinc finger proteins are known to possess an anti viral effect; due to the cleavage of the polya end of the mrna, they induce and enhance rna turnover in cell [12, 13] . the introduction of domains with high catalytic nuclease activity into these proteins pro motes enhancement of antiviral properties. for exam ple, a hybrid construct based on a synthetic protein that belongs to this group and staphylococcus nuclease was obtained that prevents the replication of the dna containing human papilloma virus, [14] . monocyte chemoattractant protein induced pro tein 1 (mcpip1) also belongs to zinc finger proteins. the protein contains two conserved domains, i.e., the ccch sequence (zinc fingers) and nyn nuclease domain. mcpip1 is involved in the regulation of the inflammatory response in cell, and it is the nuclease domain that binds and destroys the viral rna [15] . this requires rnase activity and dimerization of the protein. mcpip1 cleaves viral rna and cellular mrna, as well as the mcirorna precursor, in a mg 2+ dependent reaction [16] . an increased level of the protein induced by inflammatory cytokines (such as tumor necrosis factor α (tnf α), interleukin 1β, lipopolysaccharides) inhibits the replication of den gue fever virus and japanese encephalitis virus. how ever, three other proteins of the mcpip group that contain both the ccch sequence and nuclease domain, but have no proline rich domain and thus are unable to form dimers, possess no antiviral activity [15] . these data emphasize the requirement for the dimerization of the mcpip proteins for manifestation of antiviral activity independently of the presence of the zinc finger domain in the molecule. the main rnases associated with eosinophils, the eosinophil cationic protein (ecp) and eosinophil derived neurotoxin (edn), possess antimicrobial, antihelmintic, and antiviral activity caused by their ability to catalytically cleave ssrna. these rnases are considered as potential agents against viral infec tions of the lungs [17] . at the level of amino acid sequences, they possess certain homology with bovine pancreatic ribonuclease and belong to a large super family of rnase a, the members of which have disul fide bonds in their structures. ecp, or rnase 3, is the most cationic (pi = 11) and the least catalytically active protein of the family, and edn (rnase 2, pi = 9) possesses approximately 100 fold higher activity [17] . only edn that possesses a unique loop of nine amino acid residues (l7) that differs different from a similar loop in ecp at its c terminus exhibits high activity against the respiratory syncytial virus associated with the contribution of this structure to interaction of rnase with viral capsid and penetration inside the vir ion [18] . rosenberg [19] , who studies eosinophil associated rnases, supposes that respiratory viruses containing ssrna are evolutionarily established mobile targets for edn, which directly utilizes its ribonucleolytic activity for the antiviral effect. fur thermore, in experiments in vitro, edn decreased the infecting ability of another ssrna containing virus, i.e., human immunodeficiency virus (hiv 1) [20, 21] . previously, onconase, an rnases from oocytes of the leopard frog rana pipiens, efficiently suppresses the replication of hiv 1 due to the selective degrada tion of viral rna, which exhibits no pronounced cytotoxic effect on infected human cells [22] . later, onconase was found to be capable of degrading cell trna, but not the rrna and mrna protected with proteins. this accelerates the trna degradation/syn thesis cycle and degradation products, which can probably serve as primers for viral replication, are also destroyed by onconase, leading to the inhibition of virus replication [23] . an rnase from the r. catesbei ana frog, homologous to onconase, efficiently blocks the replication of an rna containing virus of japa nese encephalitis and stimulates activation of caspases 3, 8, and 9, inducing apoptosis of infected bhk 21 cells [24] . modern studies demonstrated that both onconase and rnase a are inefficient with respect to the respiratory syncytial virus [28] . at the same time, onconase and ramphinase 2 (a recombinant protein similar to onconase) inhibited the replication of dna containing viruses, such as herpes simplex virus types 1 and 2, epstein-barr virus, kaposi sarcoma associated herpes virus, cytomegalovirus, and roseolovirus, without causing infected cell death; the two latter virus types were the most sensitive to these rnases [25] . therefore, the antiviral effect, even of closely related amphibian rnases, does not cover all viruses; certain rnases are active against certain viruses. this is due to the specific features of the struc ture of various viruses, the versatility of the organiza tion, and the properties of the cell they target, as well as the variability of molecular structures and the level of rnase catalytic activity. rnase a the earliest studies on the antiviral activity of rnases were performed using pancreatic rnase as an agent that quickly normalized the state and decreased the symptoms of meningitis and cerebrospinal pleocy tosis in patients with tick borne encephalitis [26] . the first preparation was registered as amorphous ribo nuclease (registration number 68/333/22, registration date april 30, 1968 ). today, cattle pancreatic ribonu clease (rnase a) is produced in russia by the sam son med joint company under the trade name of ribonuclease (registration number ls 000391, date of registration april 10, 2010) in the form of tablets and lyophilizate for preparing injections and local adminis tration solution. the preparation is advised for inflam matory disorders of the airways (tracheitis, bronchitis, pneumonia, bronchiectatic disease, sinusitis), parad ontosis, osteomyelitis, thrombophlebitis, abscesses, viral meningitis, and tick borne encephalitis [27] . therefore, the only approved rnase based antiviral preparation is the preparation obtained from the bovine pancreas. today, the improvement of the antiviral agents based on rnase a is ongoing. conjugates of rnase a with ligand free human serum albumin that, unlike the initial enzyme, exhibit activity against dsrna and possess high activity against influenza a and b viruses have been created [28] . rnase a is a component of a complex with gold nanoparticles and oligonucleotides complementary to rna sequences (nucleotides at positions 322-339) of hepatitis b virus. the complex decreased the content of viral rna in mice with hep atitis b by 99% [29] . despite the high probability of inhibiting the catalytic activity of rnase a by cell cytosol inhibitor [30, 31] , its functions as of one of the major representatives of the wide family of mamma lian rnases in the evolutionarily developed system of non specific immunity are doubtless [32] . bovin pancreatic rnase does not possess consider able activity against hiv 1, while bovine seminal rnase (bs rnase) inhibited the replication of the virus in h9 leukemia cells [33] . it was demonstrated that cleavage of dsrna by bs rnase is enhanced in the presence of interferon γ, which probably contrib utes to the mechanisms of antiviral immune defense [34] . let us note that bs rnase is a natural dimer, monomers of which are linked by two intramolecular disulfide bonds. this structure imparts the molecule stability against cytosolic rnase inhibitor and decreases its toxic effects compared to the monomer [33] . it should also be noted that many rnases tend to form oligomeric structures, including rnase a lyo philized from a solution in 40% acetic acid forms dimers, trimers, tetramers, and higher order multim ers [36] . dimers are formed via the exchange of the terminal domains between the monomers (either c or n terminal dimers). an important factor that pro motes oligomerization is the hydrophobic nature of the c terminal part of the molecule and hydrophilic nature of the n terminal part [37] . in all studied crys tal structures of a microbial rnase binase, there are features that indicate dimer formation, in which active center of one of the subunits is closed due to interac tions between the subunits [38] . α helices of the mol ecules of bs rnase, rnase a, human pancreatic rnase h, and binase contain hydrophobic segments capable of participating in both the interaction with the lipid bilayer and dimerization [39] . among the rnases discussed thus far, only the bs rnase is an established natural dimer. however, the data on the need for dimer formation by the monomers of rnase l and mcpip1 [7, 8, 15, 16] for them to acquire the ability to destroy the viral genetic material evidence that the contribution of supramolecular organization of rnases to their antiviral activity has not yet been sufficiently studied. the clinical application of mammalian rnases is not always efficient, since a specific inhibitor present in practically all tissues and cells and necessary for cell protection from its own rnases [31] blocks their cat alytic activity. the inhibitor does not deactivate bacte rial rnases, and broad possibilities for the design of simple bioengineered constructs based on microbial rnases make them especially attractive for the devel opment of new therapeutic agents. a series of experimental works of the end of the 20th century was devoted to the comparison of antivi ral activity of pancreatic and microbial rnases, in particular, rnase from actinomyces rimosus. both native and dextran modified microbial rnase caused greater and more prolonged effect on a dna contain ing aujeszky's disease virus than rnase a [40] . binase, or rnase of bacillus intermedius (modern title b. pumilus [41] ), well studied by now, exhibited high activity against the rna containing street rabies virus in infected guinea pigs, rabbits, and mice when injected to the site of infection [42, 43] . therapeutic effect of binase was registered both 2-3 h after infec tion and 1 day later (57-67% animal protection); the enzyme did not affect the formation of vaccine immu nity. a single intraperitoneal injection of binase to rab bits infected with foot and mouth disease virus type o and type a22 550 decreased animal mortality by threefold [44] . binase also possesses activity against influenza a/bethesda/10/63, a/odessa/2882/82, and b/leningrad/369/76 viruses comparable to that of a classic antiviral agent, rimantadine. binase was found to be active against influenza virus types a and b, while rimantadine is not active against influenza virus type b [45] . recently, we demonstrated that, at the non toxic concentrations to epithelial cells, binase exhibited antiviral activity against the pandemic influ enza a/hamburg/04/09 (h1n1) virus, the causal agent of the epidemic in 2009, upon both single and multicycle virus reproduction. the short term treat ment of virus infectious particles (15-30 min) with binase at increasing concentrations proportionally decreased the viability of the virus, which manifested by weakening its ability to infect lung adenocarcinoma cells a549 by almost an order of magnitude (fig. 2 ) [46] . importantly, binase does not induce expression of specific marker of immune response antigen cd69 and synthesis of interferon γ in population of cd8+ and cd4+ t lymphocytes, which evinces that the enzyme lacks the ability to induce polyclonal t cell response of the superantigen type [47] . screening for bacterial rnases that possess new antiviral properties continues. works on the isolation and characteristics of secreted rnases by the bacteria of the genus pseudomonas are ongoing [48] . the intra cellular ribonuclease of b. cereus was found to be effi cient against the tobacco mosaic virus [49] . culture fluid of b. pumilus isolated from the sea sponge petro mica citrine possesses antiviral activity with respect to bovine diarrhea virus [50] and the b. pumilus strain var. pashkov from midland soils exhibits a wide spec trum of antagonist activity, including the antienteroviral activity [51] . most likely, the antiviral properties of the bacillus cultural fluid are largely caused by the secreted rnases that correspond or are similar to binase. starting in the late 1990s of the 20th century, syn thetic rna hydrolyzing molecules generated from peptides and containing l lysine, histamine, or histi dine methyl ester residues have been developed [52] . chemical conjugates of lysine moieties with imidazole model the active center of rnase, contain the rna binding and rna hydrolyzing domains, and may find application for inactivation of rna in gene targeting therapy [52] . mimetics of rnases of another class have been created based on the conjugates of diazabi cyclo [2.2.2] octane with imidazole; the rate of rna hydrolysis by these mimetics increases proportionally to the number of positive charges in the molecule [53] . recently, synthetic rnases were found to act not only on rna containing viruses through hydrolysis of viral rna [54] , but also on dna containing viruses, in particular cowpox virus, through the destruction of the virus envelope [55] . of antiviral rnases modern antiviral agents should be used with due regard to the data on mechanisms of action and the targets whose damage leads to virus elimination. the most general effect is produced by preparations con taining interferon as a stimulator of the cell's natural defense system against the virus or synthetic analogues of nucleosides that block the synthesis of viral nucleic acids. the effect of other agents is selectively targeted against various stages of viral infection development and the life cycle of the virus, i.e., adsorption, penetra tion, synthesis of virus components, and the exit of daughter virions form cell. agents that act upon virus genome are of particular interest; they include anti sense oligonucleotides [56] , ribozymes [57] , and rnases discussed here. these agents suppress virus production, but they are probably able to destroy latent virus infection. here, we consider three possible mechanisms of the effect of binase on rna contain ing viruses, which may be exerted at any stage of cell infection. at the first stage, when binase meets the virus outside cell, its catalytic activity is not inhibited by the natural rnase and it may destroy viral rna (fig. 3, c) . mechanism of binase penetration inside the virion is not clear, however it has been proven that virus infecting ability decreases upon direct treatment of virus particles with binase [46] . at the next stage, binase may interact with the virus inside an endosome since endosomal type of internalization is characteris tic for exogenous rnases, e.g. α sarcine [58] , rnase a [59] , bs rnase [60] , and binase [61] (fig. 1) . finally, penetration of binase into cell nucleus is of particular importance: here the enzyme may directly destroy viral rna (fig. 3, a and b) . today, localization of exogenous rnases in cell nucleus has been convinc ingly demonstrated only for bs rnase [60] and binase [61] . it should be noted that binase penetrated not all cells: for example, the enzyme did not enter the alveolar epithelium mle 12 cells expressing viral t antigen on their surface, but rather caused their death [62] . since a number of facts that indicate the interaction of rnases with cell surface structures has been accumulated [63] , the contribution of these structures to the internalization of rnases by infected cells should be taken into account. therefore, for the development of highly efficient antiviral preparations based on rnases, knowledge of the exact stage at which the enzyme affects the virus is obligatory. furthermore, careful attention is focused on the possibility of the intervention of exogenous rnases in the process of rna interference involved in protec tion against viruses [64, 65] . the leading role is played by the dicer rnase producing small interfering rnas (sirnas) and using dsrnas (an intermediate product of virus replication) as a substrate [64] . furthermore, it has been found that sirnas specific to a conserved region of influenza virus rna introduced into a cell decreased the titer of the virus [65] . antiviral potential of sirnas is increased upon application in a complex with polycationic carrier [65, 67] . the application of sirnas in antiviral therapy is not limited to the treat ment of the influenza virus. positive results have been obtained in experiments on laboratory mice infected with a coronavirus causing severe respiratory syn drome and syncytial virus [64] . so far, there are few explicit data on the participation of exogenous rnases in formation and destruction of sirnas. it was dem onstrated that onconase changes the sirna expres sion profile in several pleura mesothelioma cell lines through the destruction of precursors of these mole cules and thus decreasing the amount of substrate for the dicer rnase [68] . therefore, the mechanisms of the antiviral activity of rnases include both the direct effect on the nucleocapsid and nucleic acid and indi rect effects, i.e., intervention into the rna interfer ence, immunomodulation, and induction of apoptosis in infected cells. figure 3 demonstrates hypothetical models of the elimination of viral infection by an exogenous rnase in function of the type of interac tion with cell: independent penetration (a), joint internalization (b), or outside cell (c). considerable economic losses from yearly epidem ics cause constant search for new antiviral agents that become useless with time due to high variability of viruses. the study of the molecular mechanism of the action of antiviral rnases is undoubtedly an urgent task, the solution of which may promote the develop ment of novel antiviral preparations capable of pro tecting the organism independently of changes in the virus genome. exoribonucleases and their multiple roles in rna metabolism inhibition of rna synthesis and reproduction of tick encephalitis virus under the influ ence of ribonuclease effect of 1,3;1,6 β d glucan on infec tion of detached tobacco leaves with tobacco mosaic virus effective expression of the gene encoding an extracellu lar ribonuclease of zinnia elegans in the sr1 nicotiana tabacum plants ribonu cleases in bacterial toxin-antitoxin systems structure function rela tions in the ntpase domain of the antiviral trna ribotoxin escherichia coli prrc small self rna generated by rnase l amplifies antiviral innate immunity mecha nistic insights into rnase l through use of an mdmx derived multi functional protein domain influenza a induced cellular signal transduction pathways a viral rna competi tively inhibits the antiviral endoribonuclease domain of rnase l evasion of antiviral innate immunity by theiler's virus l* protein through direct inhibition of rnase l multiple modes of rna recognition by zinc finger proteins inhibition of filov irus replication by the zinc finger antiviral protein gene and protein delivered zinc finger staphylococcal nuclease hybrid for inhibition of dna replication of human papillomavirus mcpip1 ribonuclease exhibits broad spectrum antiviral effects through viral rna binding and degradation mcpip1ribonuclease antagonizes dicer and terminates microrna biogenesis through precursor microrna degradation eosino phils, eosinophil ribonucleases, and their role in host defense against respiratory virus pathogens an insertion in loop l7 of human eosi nophil derived neurotoxin is crucial for its antiviral activity ribonucleases, nucleic acids and molecular biology ribonuclease is partly responsible for the hiv 1 inhib itory effect activated by hla alloantigen recognition ribonucleases in hiv type 1 inhibition: effect of recombinant rnases on infection of primary t cells and immune activation induced rnase gene and protein expression inhibition of hiv 1 production and selective degradation of viral rna by an amphibian ribonuclease entry into cells and selec tive degradation of trna by a cytotoxic member of the rnase a family rana catesbeiana ribonuclease inhibits japanese encephalitis virus (jev) replication and enhances apoptosis of jev infected bhk 21 cells us patent ribonuclease treatment of tick borne encephalitis lekarstvennye sredstva: 5000 naime novanii preparatov i ikh form (svoistva, primenenie, vzaimodeistvie, protivopokazaniya) [medicines: 5000 names of preparations and their forms (properties, appli cations conjugates of pancreatic ribonuclease and ligand free human serum albumin nanoparticle based artificial rna silencing machinery for antiviral therapy cytotoxic ribonu cleases: molecular weapons and their targets x ray structure of two crystalline forms of a strep tomycete ribonuclease with cytotoxic activity rnasea ribunucleases: ancient components of nonspecific defense system of the respi ratory tract rnase inhibition of human immunodeficiency virus infection of h9 cells interferon gamma activates the cleavage of double stranded rna by bovine seminal ribonuclease cytotoxicity of bovine sem inal ribonuclease: monomer versus dimer oligomerization of ribo nuclease a: two novel three dimensional domain swapped tetramers increase of rnase a n terminus polarity or c terminus apolarity changes the two domains' propensity to swap and form the two dimeric conformers of the protein structure and functional studies of the ribonuclease binase glu43ala/phe81ala mutant a hydrophobic segment of some cytotoxic ribonucleases antiviral activity of modified rnases barnase and binase: twins with distinct fates antiviral activity of bacillus intermedius rnase in experiments on cda mice infected with street rabies virus protective activity of bacillus intermedius rnase in guinea pigs and rabbits infected with street rabies virus comparative analysis of antiviral activity of pancreatic and microbial rnases anti flu effect of bacterial rnase in experiment, and pharmacokinetic rationale for the method of its application antiviral activ ity of binase against the pandemic influenza a (h1n1) virus binase induces apoptosis of transformed myeloid cells and does not induce t cell immune response extra cellular ribonu clease production from pseudomonas species purification and some properties of an extracellular ribonuclease with antivi ral activity against tobacco mosaic virus from bacillus cereus antiviral activity of bacillus sp. iso lated from the marine sponge petromica citrina against bovine viral diarrhea virus, a surrogate model of the hepatitis c virus experimental study of antiviral activity of spore forming bacteria bacillus pumilus pashkov artificial ribonu cleases: 1. synthesis and properties of conjugates con taining an rna binding fragment with lys residues and an rna hydrolyzing fragment with imidazole res idue chemical ribonucleases: 2. design and hydrolytic activity of the ribonuclease mimics on the basis of diazabicyclo[2.2.2]octane with a differing number of positive charges inactivation of a non enveloped rna virus by artificial ribonucleases: honey bees and acute bee paralysis virus as a new experimental model for in vivo antiviral activ ity assessment novel amphiphilic compounds effectively inactivate the vaccinia virus preparation of azacrown functionalized 2' o methyl oligoribonucleotides, potential artificial rnases targeting mrnas by engineered sequence specific rnase p ribozymes cyto toxic mechanism of the ribotoxin alpha sarcin. induc tion cell death via apoptosis secretory ribonucleases are internalized by a dynamin independent endocytic pathway essential stations in the intracellular pathway of cytotoxic bovine seminal ribonuclease internalization of bacillus intermedius ribo nuclease (binase) induces human alveolar adenocar cinoma cell death il'inskaia o.n. 2012. binase penetra tion into alveolar epithelial cells does not induce cell death cell targets of antitumor ribonucleases rna interference against viruses: strike and counter strike inhibition of influenza virus production in virus infected mice by rna interference sirna for influenza therapy an influenza virus inspired polymer system for the timed release of sirna onconase downregulates microrna expression through targeting microrna precursors the work was performed according to the russian government program of competitive growth of kazan federal university and was supported by the russian foundation for basic research (project no. 2 04 01226 a) and russian scientific foundation (project no. 14 14 00522). key: cord-339716-1khdh9nf authors: munasinghe, sithum; sperandei, sandro; freebairn, louise; conroy, elizabeth; jani, hir; marjanovic, sandra; page, andrew title: the impact of physical distancing policies during the covid-19 pandemic on health and well-being among australian adolescents date: 2020-10-21 journal: j adolesc health doi: 10.1016/j.jadohealth.2020.08.008 sha: doc_id: 339716 cord_uid: 1khdh9nf purpose: physical distancing policies in the state of new south wales (australia) were implemented on march 23, 2020, because of the covid-19 pandemic. this study investigated changes in physical activity, dietary behaviors, and well-being during the early period of this policy. methods: a cohort of young people aged 13–19 years from sydney (n = 582) were prospectively followed for 22 weeks (november 18, 2019, to april 19, 2020). daily, weekly, and monthly trajectories of diet, physical activity, sedentary behavior, well-being, and psychological distress were collected via smartphone, using a series of ecological momentary assessments and smartphone sensors. differences in health and well-being outcomes were compared preand post-implementation of physical distancing guidelines. results: after the implementation of physical distancing measures in nsw, there were significant decreases in physical activity (odds ratio [or] = .53, 95% confidence interval [ci] = .34–.83), increases in social media and internet use (or = 1.86, 95% ci = 1.15–3.00), and increased screen time based on participants' smartphone screen state. physical distancing measures were also associated with being alone in the previous hour (or = 2.09, 95% ci: 1.33–3.28), decreases in happiness (or = .38, 95% ci = .18–.82), and fast food consumption (or = .46, 95% ci = .29–.73). conclusions: physical distancing and social restrictions had a contemporaneous impact on health and well-being outcomes associated with chronic disease among young people. as the pandemic evolves, it will be important to consider how to mitigate against any longer term health impacts of physical distancing restrictions. aged children, a move to the online delivery of schooling. authorities requested that people remain in their homes wherever possible and limit their travel to obtaining essential goods and services. this public health strategy was absolutely necessary and appears to be yielding the desired result in terms of "flattening the curve" in the australian context [1] . there are potential impacts of physical distancing and social isolation, particularly among younger people, where social connection is a key part of psychosocial development. the necessary policy responses to covid-19 may impact the determinants of poor mental health outcomes, including suicidal behavior [2] . previous studies have shown psychological and physical health impacts of social isolation during quarantine [3] , and more generally, social isolation has been shown to be associated with poor mental and physical health outcomes [4] . in addition, adolescents are likely to have reduced physical activity, particularly incidental physical activity, and increased screen time as a consequence of the physical distancing measures. previous studies have shown the impacts of sedentary behavior on health outcomes in young people [5, 6] and interrelated factors of diet, overweight and obesity, and well-being [5, 7, 8] . the impact of the public health interventions in response to covid-19 to the daily routine of young people in australia on key health and well-being measures known to be associated with chronic disease has not previously been investigated. accordingly, this study investigates whether the physical distancing policies and school closures in the state of new south wales (australia) were associated with changes in physical activity, dietary behaviors, and well-being during the early period of this policy. participants were recruited as part of a broader prospective cohort study of adolescents investigating determinants of health and well-being over time. young people were recruited via social media (instagram and facebook) from the general population aged 13e19 years of a sydney population catchment. promotional and recruitment materials were developed and modified by members of a youth advisory group, and the social media strategy targeted those residing in western sydney; however, participants from areas outside of this catchment were not excluded if they enrolled in the study. the western sydney population catchment is a socioeconomically and ethnically diverse population of approximately one million people. participants were followed prospectively over a period of 22 weeks, from november 8, 2019, to april 19, 2020, after a social media campaign that ran from november 8, 2019, to january 8, 2020. institutional ethics approval for the study was obtained from the western sydney university human research ethics committee (hrec approval number: h13302). the total reach of the social media recruitment campaign was 164,640 adolescents in the western sydney area, of which 61% were female (n ¼ 100,640) and 39% were male (n ¼ 62,944). the total number of impressions (i.e., the number of times advertisements were displayed in news feeds) was 1,389,957, and this was higher among females (n ¼ 955,418, 69%) than males (n ¼ 425,222, 31%). the total number of click-throughs to the study webpage was 11,048, with a higher level of interest among females (n ¼ 8,295, 75%) than males (n ¼ 2,680, 25%). of 11, 048 individuals who clicked through to the study website, a total of 1,298 participants enrolled in the study and completed the baseline questionnaire, from which 582 participants were selected who provided one or more responses to follow-up ecological momentary assessment (ema). participants were predominantly female and aged 16e18 years (table 1) , reflecting the higher engagement in instagram and facebook among females than males more generally [9, 10] . the ethica data smartphone app (https://ethicadata.com/ product) was used to collect data from questionnaires, emas, and smartphone sensors. mobile sensor data were collected automatically through the ethica app only from those participants who provided consent and included geolocation information (via gps, wi-fi, and bluetooth), pedometer, motion-based activity recognition (mbar) data, and screen state (whether the screen of the smartphone is "on" or "off"). a baseline questionnaire and a 16-week schedule of follow-up emas were triggered when participants enrolled in the study, with questions sent directly to each participant's smartphone. there were nine emas relating to psychological distress, well-being, positive emotion, social networks, relationships, diet, physical activity, sleep, and academic behavior. each ema, except psychological distress and well-being, was administered weekly, but on different days. emas relating to psychological distress or well-being were administered monthly. thus, participants received daily emas but received a different ema on each day. emas were sent to participants at random times between 8 a.m. and 10 a.m. or between 3 p.m. and 8 p.m. to avoid notifications during school hours and periods when participants may have been sleeping. the 16week schedule of emas resulted in weekly or monthly measures for each domain spanning the 22-week follow-up period. the primary outcome variables for this study included measures of physical activity, sedentary behavior, dietary behavior, and psychological well-being. self-reported physical activity at baseline was based on responses to the pace þ adolescent physical activity measures [11] , and sedentary behavior was based on the adolescent sedentary activities questions [12] with the tv and computer items modified to also capture information on internet streaming, mobile phone, tablet, or gaming console use. self-reported physical activity and sedentary behavior relating to the previous 24-hour period were also collected each week for the 22week follow-up period via an ema. questions included: (i) "in the past 24 hours, were you physically active for a total of 60 minutes or more? 'physical activity' is any activity that increases your heart rate and makes you get out of breath some of the time"; (ii) "in the past 24 hours, did you spend any time watching tv?"; and (iii) "in the past 24 hours, did you spend any time on the internet, social media (like instagram, youtube, or facebook), or playing computer games?" for participants who answered "yes" to this question, a follow-up question was asked: "if yes, how long did you spend on the internet, social media, or playing computer games?" additional information on physical activity was collected passively via smartphone sensors, including pedometer, screen state (i.e., whether the phone was "on" or "off"), and mbar. the daily number of steps for each participant was collected via the pedometer. screen state was used as a proxy measure of sedentary behavior, with the assumption that during periods where the phone screen was active, participants were less likely to be engaging in physical activity. mbar is a composite indicator of activity provided by the ethica data app, which combines information from the phone sensors, including accelerometer, gyroscope, gravity, and magnetic field [13] . the mbar indicator is a categorical variable that divides each moment into an activity type: "on foot," "walking," "running," "on bicycle," "in vehicle," "unknown," "still" (the device is not moving), and "tilting" (the device angle relative to gravity has changed significantly). each categorization is also ascribed a confidence level score between 0 and 100. in the present study, each participant's mbar category was weighted by this score, such that categories with high confidence level scores were considered a more accurate assessment of the type of activity. self-reported dietary behavior at baseline was measured using questions validated for adolescents by the nsw centre for public health nutrition [14] to allow comparisons with dietary guidelines for children and adolescents in australia [15] . selfreported dietary behaviors relating to the previous 24-hour period were also collected each week for the 22-week followup period via an ema. questions included: (i) "in the past 24 hours, have you eaten any serves of fruit?" if participants responded "yes," a follow-up question was asked: "how many serves of fruit? (a serve ¼ 1 medium piece or 2 small pieces of fruit or 1 cup of diced pieces)"; (ii) "in the past 24 hours, have you eaten any serves of vegetables?" if participants responded "yes," a follow-up question was asked: "how many serves of vegetables? (a serve ¼ 1/2 cup cooked vegetables or 1 cup of salad vegetables)"; and (iii) "in the past 24 hours, have you had any meals or snacks such as burgers, pizza, chicken, or chips from places like mcdonalds, hungry jacks, pizza hut, kfc, red rooster or local takeaway food places?" if participants responded "yes," a follow-up question was asked: "how many meals?" psychological well-being self-reported psychological distress was based on the kessler psychological distress 6-item scale (k6) [16] . response options for each k6 item included "none of the time," "a little of the time," "some of the time," "most of the time," and "all of the time" and were scored in the range of 1e5 respectively. a score 19 was used as indicative of probable mental disorder as recommended [16] ; however, it is important to note that this standard cut point may overlook those with more moderate levels of psychological distress that may still be important [17] . the engagement, perseverance, optimism, connectedness, and happiness (epoch) measure of well-being was also included in the study to capture information on positive psychological characteristics [18] using a 5-point scale from "almost never" to "almost always." the k6 and epoch questionnaires (supplementary materials) were completed by participants at baseline with follow-ups sent to each participant every 4 weeks and short emas relating to selected epoch items sent weekly [19] . in addition, social relationships were measured based on the question: "in the past hour, who were you with?" participants could respond to one or more of the following options: "alone," "mother," "father," "sister(s)," "brother(s)," "other relatives," "classmates, peers," "strangers," "boyfriend or girlfriend," "friends," and "other, please specify." for participants who answered "friends," an additional question was asked: "how many friends?" finally, self-reported sleep duration in the previous 24 hours was also collected at baseline via a weekly ema over the 22-week follow-up period. a range of sociodemographic and other health factors were also collected at baseline. these factors included sex, age, language spoken at home, current year of school and educational achievement, employment status, income, and body mass index (based on self-reported height and weight; table 1 ). the change in measures of physical activity, dietary behavior, and well-being was compared pre-and post-implementation of the nsw guidelines for physical distancing to determine whether this policy resulted in significant changes in these key health behaviors. these guidelines officially came into effect on march 31, 2020 [20] ; however, physical distancing began in the earlier period of march with the closure of pubs, clubs, gyms, cinemas, places of worship on march 23, 2020 [21] and evidence of parents keeping children at home from school. accordingly, the period for when physical distancing began to be implemented was defined as march 23, 2020. analyses were restricted to those participants who completed at least one ema over the follow-up period (n ¼ 582; table 1 ). participants were predominantly female, with a median age of 17 years (interquartile range, 16e18). most participants spoke english at home (86%), were either in their senior year of schooling (23%) or finished school (43%), and almost 60% worked in a job (mainly part time). these participants contributed 4,805 responses to emas over the 22-week follow-up period, including 301 responses in the period after implementation of physical distancing guidelines ( table 2 ). the mean number of emas per week for this group was 9.6 (standard deviation ¼ 5.8), and the median number of emas per week was 10 (interquartile range ¼ 3e16). comparisons of participant characteristics between (1) those who completed baseline and follow-up, (2) those who completed emas pre-and post-implementation of the physical distancing policy, and (3) those who provided or did not provide sensor are provided in supplementary tables 1 and 2 descriptive plots of trajectories of physical activity were examined over the 22-week follow period, based on daily pedometer data, mbar, and weekly self-report emas. trajectories of self-reported fruit, vegetable, and fast food consumption were also examined based on weekly emas, as were trajectories of psychological well-being based on distress, well-being, and sleep duration. multivariate multilevel mixed effect logistic regression models were conducted to investigate associations between the implementation of nsw guidelines (specified as a binary pre-post variable on march 23, 2020) and subsequent changes in physical activity, dietary behavior, and well-being measures. there were significant decreases in physical activity in the period after the implementation of physical distancing measures in nsw. adolescents were significantly less likely to report 60 minutes of physical activity in the previous 24 figure 1a ). declines in physical activity were also evident based on the average number of steps per day and mbar (figure 2a,b) . there was also a significant increase in sedentary activity postimplementation of physical distancing, with higher social media and internet use (or ¼ 1.86, 95% ci ¼ 1.15e3.0; table 3, figure 2a ) and also evidence of increased screen time based on participants' smartphone screen state ( figure 2c ). the implementation of physical distancing measures was associated with lower levels of happiness (or ¼ .38, 95% ci ¼ .18e.82) and positive emotions (or ¼ .23, 95% ci ¼ .14e.39), respondents reporting being alone in the previous hour (or ¼ 2.09, 95% ci ¼ 1.33e3.28), and slightly higher increases in psychological distress (or ¼ 1.48, 95% ci ¼ .74e2.95; table 3 , figure 2b ). there were also declines in fast food consumption following implementation of physical distancing (or ¼ .46, 95% ci ¼ .29e .73) but no substantial changes in fruit and vegetable consumption, tv watching, or sleep duration (table 3 ; figure 1c ). this study investigated the impact of physical distancing guidelines implemented in new south wales, australia, on a range of health and well-being outcomes among a cohort of adolescents aged 13e19 years in sydney. the implementation of physical distancing interventions was associated with decreases in physical activity and well-being, and increases in being alone and social media and internet use in the 4 weeks after the policy was implemented. there was also a decrease in selfreported fast food consumption in the 4 weeks after the policy was implemented, but little change in fruit or vegetable consumption. these findings suggest that the substantial changes to the way in which communities are currently functioning, particularly for young people, has had a contemporaneous impact on health and well-being outcomes associated with chronic disease. an important finding in the present study were the decreases in happiness reported after the implementation of the physical distancing guidelines and a higher likelihood of being alone during this period. social isolation is an important risk factor for poorer psychological well-being among young people and, conversely, peer-, family-and school-connectedness play key roles as protective factors [22] . these protective connections may not have been as accessible to young people during the period of physical distancing resulting in lower levels of psychological well-being. it will be important to ensure that protective connections and other strategies to support the well-being of young people are maintained, to mitigate the potential psychological impact on young people. in australia, covid-19 cases remain low at the time of reporting; however, it is possible that physical distancing restrictions and online education may need to be reinstated if a second or third wave of infections eventuates. the shift to online delivery of education in nsw and the requirement to defer any nonessential travel is reflected in the increase in social media and internet use for the corresponding period in this study. there was also a decrease in physical activity likely related to the suspension of school and community sport and potentially mediated by a lack of access to green space in home environments. recent reviews have suggested both positive and negative impacts of social media, determined by the type of involvement (e.g., passive use, high investment, or support seeking) as well as the amount of time spent on screenbased activity [7, 23, 24] . in addition, some studies have found that screen-based sedentary behavior supplants time spent sleeping or engaged in physical activity [7] . the present study did not directly examine the association between screen-based sedentary behavior and physical activity, but while the pattern of findings is consistent with the idea of displacement, this may only be relevant when time is constrained (such as during school term or nonholiday periods). the finding that sleep hours did not decline contemporaneously with increased screen time perhaps suggests study participants had more time to engage in sedentary behavior without disrupting sleep duration. it remains to be seen whether sedentary behavior observed during the period of physical distancing will revert back to levels observed before physical distancing measures. this will be an important focus for future research, given the evidence that sedentary habits in adulthood are typically established during adolescence [12] . an interesting finding was the decrease in fast food consumption in the context of limited changes to fruit and vegetable consumption. this likely reflects a decrease in opportunistic purchases of fast food during the day and traveling either to school or to work. previous research has found increased consumption of this food type among adolescents and young people where there is a high density of fast food outlets located near schools and transport hubs [25, 26] . since the initial period of physical distancing, many fast food outlets have moved to take away and home delivery; however, the reduced consumption observed may indicate that fast food consumption was opportunistic and more associated with connecting socially with friends [26] . future studies could consider the impact of these changes on food delivery on the consumption of fast food among younger people of different ages and with differing discretionary income and access to private transport. the present study also found that consumption of fruit and vegetables did not increase, suggesting either that similar food types were substituted or there was a decrease in overall caloric intake. consumption of calorie-dense foods can be positively associated with feelings of stress, and given the reduction in fast food consumption occurred in the context of increased social isolation and psychological distress, this might explain the lack of nutritional substitution implied in this finding. despite reduced consumption of these food types via fast food outlets, there may have been an overreliance on processed supermarket food during this periodda limitation to this finding was that more specific questions relating to processed or junk food (i.e., not fast food purchases) were not explicitly measured. australia experienced panic buying of processed foods resulting in supermarkets placing limits on a number of food items because of shortages. however, this was not observed for fresh fruit and vegetables. alternatively, it may be that the development of new healthpromoting behaviors takes time to develop, and the observation period of the present study was not long enough for this to emerge. there are a number of methodological limitations to this study. first, although there was a positive response to the study through instagram and facebook, participants who were more likely to engage were overwhelmingly female and more likely to be older in age (16e18 years). the higher proportion of females may reflect greater engagement in social media among females than males, a phenomenon that has been noted in representative studies of social media use in australia [9, 10] . despite the imbalance by sex, the distribution of responses by key dietary behaviors, physical activity, and wellbeing outcomes was not substantially dissimilar to other representative prevalence studies of adolescents [26, 27] . the higher proportion of older-age adolescents likely reflects that for those aged 13e15 years, parental or guardian consent was required before enrollment in the study. this involved additional steps in making contact with parents or guardians via email and to arrange for links to download the ethica app, which likely discouraged some younger potential participants from enrolling in the study. an additional limitation was the low ema and follow-up survey completion rate. despite the use of an incentive (aud $30 giftpay voucher), only 45% of baseline participants (n ¼ 1,298) completed one or more subsequent ema, and <1% completed all 96 emas over the follow-up period. the weekly schedule of emas may have been too burdensome for participants, and future research may need to consider different schedules or incorporation of personalized feedback to keep young people engaged. there is also the risk of recall bias in this study, given the self-reported nature of the baseline and follow-up questionnaires. however, emas in (near) real time potentially reduce the likelihood or recall bias, in that questions relate to the immediate 24-hour period. patterns of ema responses relating to physical activity and screen time were also consistent with objective measures of physical activity based on available mobile phone sensor data, and the results were also generally comparable with previous adolescent health surveys for some of the measures [26, 27] . smartphone sensor data, collected passively from participants, were also used as proxy measures of physical activity and sedentary behavior. this was an innovative aspect of the study design and allowed comparison with ema responses and investigation of trajectories of spatiotemporal movement among participants. however, a large proportion of participants either did not turn on some smartphone sensors (e.g., geolocation) or there were intermittent trajectories of movement, where sensor data were not collected. this resulted in complete sensor information being available on only 515 participants over the follow-up period, only 40% of baseline participants (n ¼ 1,298) . the reasons for participants choosing not to engage in this aspect of the study are unclear but may relate to concerns about individual privacy, among both participants and caregivers (who were required to give parental consent for young people aged <16 years). there is also likely to be misclassification in smartphone sensor data, where periods between the initiation and cessation of a given state (e.g., "walking" in the mbar sensor) were likely overestimated, as the smartphone did not register the cessation of the state but only the initiation of the subsequent state (e.g., "still" in the mbar sensor). this means that the overall level of activity as measured by the smartphone sensor will be an overestimate; however, relative changes over time are likely to reflect actual declines or increases, and changes in emas appear to be consistent with changes in activities as measured by smartphone sensors. the present study suggests the potential immediate impacts on health behaviors that are intermediary to chronic disease outcomes. however, it is not clear whether there will be longterm psychosocial and health impacts associated with the physical distancing policies. these policies will be slowly wound back over coming weeks, and education and employment experiences will return to a degree of normality. the wider economic impacts associated with physical distancing and other policies relating to the closure of businesses and entertainment precincts on health outcomes are also not known. it is unclear whether the changes in health and well-being documented in the present study will be transient or whether there may be ongoing impacts. additional research needs to establish longer term trends in these outcomes to inform public health policy and intervention responses. this study provided a unique opportunity to measure health behaviors and psychological well-being among australian adolescents during the covid-19 pandemic. data collection occurred pre-and post-implementation of widespread physical distancing regulations in the community. these public health interventions have successfully "flattened the curve" on covid-19 to date; however, there have also been important changes among young people on a range of health and well-being outcomes. further research is needed to monitor the longer term trends in these outcomes. as the pandemic evolves, it will be important to consider how best to support psychological and physical wellbeing for young people to mitigate against potential longer term negative impacts. supplementary data related to this article can be found at https://doi.org/10.1016/j.jadohealth.2020.08.008. australian government department of health. coronavirus (covid-19) current situation and case numbers 2020 suicide risk and prevention during the covid-19 pandemic the psychological impact of quarantine and how to reduce it: rapid review of the evidence an overview of systematic reviews on the public health consequences of social isolation and loneliness child and adolescent obesity: part of a bigger picture long-term impact of overweight and obesity in childhood and adolescence on morbidity and premature mortality in adulthood: systematic review the health indicators associated with screen-based sedentary behavior among adolescent girls: a systematic review longitudinal impact of sleep on overweight and obesity in children and adolescents: a systematic review and bias-adjusted meta-analysis office of the esafety commissioner. state of play -youth, kids and digital dangers yellow social media report. melbourne: a sensis company a physical activity screening measure for use with adolescents in primary care the reliability of the adolescent sedentary activity questionnaire (asaq) available at: https://learn.ethicadata. com/documentation/data-sources/motion-sensors recommendations for short questions to assess food consumption in children for the nsw health surveys. sydney: nsw centre for public health nutrition dietary guidelines for children and adolescents in australia. canberra: commonwealth of australia the psychometric properties of the kessler psychological distress scale (k6) in a general population sample of adolescents validity study of the k6 scale as a measure of moderate mental distress based on mental health treatment need and utilization the epoch measure of adolescent well-being a comparison of affect ratings obtained with ecological momentary assessment and the day reconstruction method please cancel travel to regional nsw coronavirus: australia to close pubs, cafes and places of worship 2020 social isolation, psychological health, and protective factors in adolescence social networking sites and associations with depressive and anxiety symptoms in children and adolescentsea systematic review. child adol ment health association between social networks and subjective well-being in adolescents: a systematic review obesogenic neighbourhoods: the impact of neighbourhood restaurants and convenience stores on adolescents' food consumption behaviours overweight/obesity, physical activity and diet among australian secondary students-first national dataset 2009-10. cancer forum. the cancer council australia key: cord-327521-g5vefajw authors: spisni, enzo; petrocelli, giovannamaria; imbesi, veronica; spigarelli, renato; azzinnari, demetrio; donati sarti, marco; campieri, massimo; valerii, maria chiara title: antioxidant, anti-inflammatory, and microbial-modulating activities of essential oils: implications in colonic pathophysiology date: 2020-06-10 journal: int j mol sci doi: 10.3390/ijms21114152 sha: doc_id: 327521 cord_uid: g5vefajw essential oils (eos) are a complex mixture of hydrophobic and volatile compounds synthesized from aromatic plants, most of them commonly used in the human diet. in recent years, many studies have analyzed their antimicrobial, antioxidant, anti-inflammatory, immunomodulatory and anticancer properties in vitro and on experimentally induced animal models of colitis and colorectal cancer. however, there are still few clinical studies aimed to understand their role in the modulation of the intestinal pathophysiology. many eos and some of their molecules have demonstrated their efficacy in inhibiting bacterial, fungi and virus replication and in modulating the inflammatory and oxidative processes that take place in experimental colitis. in addition to this, their antitumor activity against colorectal cancer models makes them extremely interesting compounds for the modulation of the pathophysiology of the large bowel. the characterization of these eos is made difficult by their complexity and by the different compositions present in the same oil having different geographical origins. this review tries to shift the focus from the eos to their individual compounds, to expand their possible applications in modulating colon pathophysiology. essential oils (eos) are a complex mixture of volatile compounds that are produced by aromatic plants as secondary metabolites. they are present in all plant organs and their main role is to defend plants from aggressions by bacteria, fungi and viruses, but also by insects. there are huge amounts of eos obtained from different plants around the world, and most of them have been at least partially characterized for their antimicrobial activity against gram-positive and gram-negative bacteria, but also against other microorganisms such as fungi and virus. the composition of the eos was selected by nature during an evolutionary process lasting millions of years. their activity is the result of the competitive selection process acting on their antibacterial, antifungal and antiviral activities in a continuous evolutionary conflict between the survival of plants and the microbial aggressions. the antimicrobial strategies of eos have been to develop multi-target mechanisms of action which make it very difficult for microorganisms to become resistant to these compounds [1] . the enormous potentials for the possible use of eos as therapeutic agents against human pathogen the excessive amount of reactive oxygen species (ros) is at the basis of degenerative processes such as lipid peroxidation, protein glycation/oxidation and nitration, enzyme inactivation and dna damages that occur in many non-communicable diseases, including colitis and neurodegenerative diseases [3, 4] . some eo single molecules, such as geraniol, easily cross the blood-brain barrier and then reach all the organs in which they can exert their antioxidant activities [5] . ros exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses [6] . eos and their molecules are capable of modulating different signaling pathways that are overactivated or downregulated during acute or chronic inflammation responses [7] . the recent discovery of the complexity of the human intestinal microbiota, composed of bacteria, fungi and viruses, and its intricate pathophysiological relationships with the immune system and the enteric nervous system, makes eos truly interesting for their antimicrobial activities, often selective for the different microbial components. from this point of view, eos could be considered potential powerful modulators of the intestinal microbiota. unfortunately, most eo molecules are quickly assimilated into the small intestine and do not reach the colon, where most of the intestinal microbiota is known to reside. the release of eos into the colon, therefore, becomes a fundamental point to allow these compounds to effectively modulate the pathophysiology of the colon. from this point of view, our research group is one of the first in the world to have used a single eo molecule in human clinical trials, to modulate the microbiota and manage the symptoms associated to a functional bowel disorder such as the irritable bowel syndrome (ibs) [8] . this review explores, in a broad and modern way, the knowledge that can lead to the effective use of eos and/or their single molecules in the modulation of the physiology and pathology of the large bowel. the major components of the most common essential oils are shown in table 2 , together with their chemical structure and major biological activity. several studies have been conducted to evaluate the effects of eos in colon inflammation [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] . in particular, several preclinical studies have been conducted on validated models of colitis induced in rats or mice by administration of dextran sulphate sodium (dss), trinitrobenzenesulfonic acid (tnbs) or acetic acid. while dss and acetic acid induces chemical damage to the epithelial cells, with consequent disruption of mucosal barrier and activation of immune cells in the lamina propria by the intestinal microbiota, tnbs acts by directly haptenizing colonic autologous/microbial proteins [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] . from this point of view, dss and acetic acid are models used in a translational way for ulcerative colitis studies, while tnbs is a model with some characteristics that bring it closer to crohn's disease. these models allow researchers to evaluate the effects of different eos on clinical, histological, serological and molecular markers of colitis. clinical features of the experimental colitis are mainly represented by weight loss, changes in stool consistency and rectal bleeding, usually scored to obtain a disease activity index (dai). histological analyses are performed to evaluate the extent of ulcerated areas, alterations of mucosal architecture and inflammatory cell infiltrations. the molecular markers that are more often evaluated comprise some circulating pro-inflammatory cytokines and the colonic expression of a plethora of enzymes and factors involved in inflammation. they include cyclooxygenase-2 (cox-2), nitric oxid synthase (inos), peroxisome proliferator-activated receptor-gamma (pparγ), nuclear factor kappa-light-chain-enhancer of activated b cells (nf-kβ) or myeloperoxydase (mpo) [9] . the anti-inflammatory effects of eos on colitis models are summarized in table 3 . with regard to the mechanisms of action of eos and their single molecules at the cellular and molecular levels, we underline that it is almost impossible to understand which molecule may exert anti-inflammatory effects when eos are used. even in studies carried out on single eo molecules, it is not easy to define a main molecular target, because these compounds act in a multitarget manner ( figure 2 ). for example, the anti-inflammatory effect of these molecules could be linked to direct interaction with pro-inflammatory proteins, such as nf-kβ, pparγ cox-2 and inos, but this direct interaction still remains to be demonstrated for the majority of these molecules. a specific interaction between borneol, camphene and eucalyptol, major components of thyme eo, and pro-inflammatory enzymes such as inos and cox-2 has been only indirectly demonstrated in vitro [18] . the multitarget effect of geraniol has been clearly demonstrated in vitro, since it is capable of regulating wnt/β-catenin, p38mapk, nfκb, pparγ and cox-2 signaling pathways. the transcription factor nf-kβ seems to be a common target for many different eo molecules, such as geraniol, eucalyptol, α-pinene, and camphor [19] , even if a definitive demonstration of the binding between these molecules and their supposed target is still lacking and should be provided by using molecular modeling studies. conceptually, however, these studies on colitis should be divided between those that delivered eo as it is, without carrier or controlled release and those in which the eo was delivered with retarded release systems, in order to really reach the colon. only by using these controlled release systems can the effects of these eos be analyzed at the colon level, where the experimentally-induced inflammation mainly occurs. basing on available studies, we can conclude that eos and their constituents could be very effective against the inflammatory component of experimental colitis. unfortunately, eo complexity makes it difficult to identify all the possible molecular targets responsible for these strong anti-inflammatory effects. the majority of studies on the antioxidant effects of eos, available in the scientific literature, are based on in vitro approaches. a limiting factor of these studies is that eos can themselves be oxidized within the intestinal lumen or into the stomach, thus losing some of their antioxidant properties even before reaching the small intestine. geraniol showed good antioxidant proprieties in vitro: palmrose and citronella eos, mainly composed of geraniol, have demonstrated to have an effective antioxidant activity in vitro on human lymphocyte cells. in this model, geraniol-containing eos, at a relatively low concentration (125 ppm), protected lymphocytes from dna methylation damages induced by methyl methanesulfonate [20] . these serum doses of geraniol are easy to achieve with a diet rich in aromatic plants or with food supplements [21] . recent studies have shown that geraniol administration reduced the intestinal inflammation induced by dss [7] , but these anti-inflammatory effects could be also linked to its antioxidant activity, since its administration resulted in a decreased inos activity and a decreased lipid peroxidation, in a rat model of colitis [22] . geraniol seems to exert its antioxidant activity also indirectly, by increasing the synthesis of liver antioxidant enzymes after oral administration at 120 mg/kg, in mice [7] . ginger eo administration at 200, and 400 mg/kg, significantly reduced the intestinal lipid peroxidation, increased the expression of intestinal antioxidant enzymes and serum glutathione level in a model of colitis induced by acetic acid in rats. in this model, ginger eo was able to induce free radicals neutralization and to protect the cell membrane lipids from oxidation, in a dose-dependent manner [14] . a recent study has evaluated antioxidant proprieties of carvacrol (5-isopropyl-2-methylphenol) which is a major monoterpenic component of origan (oreganum vulgarea), a plant widely used in mediterranean cuisine. carvacrol was used in a model of experimental induction of colorectal carcinoma, by using 1,2 dimethylhydrazine and dss, in rats. carvacrol was orally administrated before and after tumor induction at a dosage of 50 mg/kg. results of this and other studies showed that carvacrol was an excellent antioxidant agent and reduced colonocyte damages caused by ros [23, 24] . thymol is a natural phenol monoterpene isomer of carvacrol. thymol is one of the major constituents (20-65%) of thyme (thymus vulgaris) eo. an in vitro study on colon epithelial cells showed that thymol, at low doses (12.5 ppm), was a protective compound against oxidative dna damage [21] . twelve aromatic molecules from basil and thyme eos have been analyzed for their antioxidant activities, and in particular eugenol, 4-allylphenol, thymol and carvacrol (5 µg/ml) have shown greater antioxidant activities, measured in vitro on by using the aldehyde/carboxylic acid assay [23] . basil eo, orally-administered, has shown beneficial effects in a model of colitis induced by acetic acid in rats, at two different doses of 160 mg/kg and 320 mg/kg die. these effects were also linked to the reduction of mpo activity in the colon wall, an enzyme clearly involved in the oxidative damages induced by colitis [15] . despite this, further confirmations should be provided by human clinical trials. basing on available data we can confirm that eos and their constituents have interesting antioxidant properties that could justify their use as therapeutic agents against chronic intestinal oxidative damages ( figure 3 ). . antioxidant effect of essential olis (eos) in the gut. the chronic low-grade inflammation or dysbiosis that very soon occurs into the gut and in the gut wall increases the level of reactive oxygen species (ros). their increased levels are effectively counteracted by eos that are able to reduce the activity and expression of enzymes, such as myeloperoxydase (mpo), cyclooxygenase-2 (cox-2) or inducible nitric oxide synthase(inos), which are the ones most responsible for ros production and for the oxidative damages related to them. there are approximately 100 trillion cells in the human body, and more than 90% of them are microbes. they make up the human microbiota, consisting of bacteria, fungi and even viruses, mainly located in the intestine where they form the intestinal microbiome. microbiota can be considered a complex human organ which closely interacts with the gut-associated linfoid tissue (galt) and with the enteric nervous system. it is involved in many digestive functions, but it is also able to modulate the physiology of the immune system both locally and in the whole body. quantitative and qualitative microbiota alterations, known as dysbiosis, may be involved in the development or in the chronicization of several diseases [24] . the analysis of the bacterial component of the intestinal microbiota, thought their 16s rrna sequences, allowed to identify 4 major phyla, firmicutes (79%), bacteroidetes (17%), actinobacteria (3%) and proteobacteria (1%). at a lower taxonomic level, the most represented bacterial genera were found to be faecalibacterium, ruminococcus, eubacterium, dorea, bacteroides, alistipes and bifidobacterium [25] . the microbiota normally represents an ecologically stable environment, but pathogenic bacterial strands or xenobiotics can interfere in this equilibrium and give rise to dysbiosis and/or colitis. the use of broad-spectrum antibiotics to counteract infectious diseases is often associated with the onset of antibiotic resistance phenomena, other than cause a transient dysbiosis in the gastrointestinal tract. in the last few years, a great effort has been made to find new strategies to overcome the rising issue of antibiotic-resistance. in this scenario, eos may have a consistent role thanks to their capacity to control and modulate bacterial growth, acting both as bacteriostatic or bactericidal agents [26] . in fact, due to their lipophilic properties, eos can penetrate membranes, and damage bacterial cell structure, making their membranes more unstable and permeable. membrane disruption may also lead to bacterial death caused by the significant leak of ions and other essential cytosolic components. these eo effects are generally more pronounced on gram-positive bacteria with respect to gram-negative ones [27] . however, it has been demonstrated that eos can also affect the bacterial cell-wall and restore antibiotic susceptibility in drug-resistant gram-negative bacterial strains [28] . several studies have explored the antibacterial properties of eo single molecules. among them, the most studied was certainly geraniol, for its interesting antimicrobial potential. geraniol antibacterial activity seems to be linked to his property to destabilize bacterial cell wall and damage transmembrane efflux pumps, thus restoring drug-sensitivity in different bacterial antibiotic-resistant strains, such as enterobacter aerogenes, escherichia coli, pseudomonas aeruginosa and acinetobacter baumannii [29] . despite being absorbed very quickly and in an active manner by the small intestine mucosa, geraniol is reported to positively modulate the colitis-associated dysbiosis when administered by oral route by using a controlled delivery system based on microencapsulation [7] . in mice but also in humans, geraniol has demonstrated to act as an excellent modulator of intestinal microbiota, capable to boost populations of butyrate-producer bacteria such as collinsella and faecalibacterium, normally reduced in the dysbiotic human intestinal flora of ibs patients [8] . it is interesting to note how geraniol antibacterial activities were selective for pathogenic bacteria and do not involved commensal species [30] . for these reasons, geraniol can be considered as an efficient positive modulator of the intestinal microbiota. another interesting eo molecule with antibacterial activities is eugenol (2-methoxy-4-(prop-2en-1-yl)-phenol), the major compound present in clove oil, but also found in many other eos. eugenol has demonstrated antimicrobial activities based on a non-specific permeabilization of the bacterial membrane with depletion of cytosolic molecules such as adenosin triphosphate (atp), necessary for bacterial metabolism and survival [31] . this effect has been observed against e. coli, listeria monocytogenes and lactobacillus sakei using the relatively low concentration of 10 mm [32] . eugenol antibacterial effects against the pathogen l. monocytogenes have been analyzed in-depth and the principal mechanism of action identified was the alteration of the respiratory bacterial chain associated with dna damages [32] . in mice, orally administrated eugenol improved the secretion of the intestinal mucus, creating a thicker intestinal layer associated with positive changes of the mucosal microbiota ecology. in particular, it has been shown that eugenol inhibited the intestinal adherence of citrobacter rodentium, a mice pathogen that shares several biochemical features with clostridium difficile in humans [33] . another interesting antimicrobial effect of eugenol was observed in p. aeruginosa and e. coli, where this compound was able to inhibit their chemical communication system, also known as quorum sensing [34] . cinnamaldehyde (2e-3-phenylprop-2-enal) is a phenylpropanoid naturally present in the plant of the genus cinnamon. cinnamaldehyde is one of the most studied eo molecules and it has been already approved as antimicrobial food preservative [2] . antibacterial effects of cinnamaldehyde have been demonstrated by using many different bacterial models, but only a few studies evaluated its impact on the whole intestinal microbiota. in vitro, cinnamaldehyde was capable to inhibit the growth of potentially pathogenic bacteria such as staphylococcus aureus, enterobacter cloacae, a. baumannii and l. monocytogenes [35] and it was able to kill a pathogenic strand of e. coli at a very low concentration (0.05% v/v) [36] . one of the proposed antibacterial mechanisms of cinnamaldehyde inhibition of e. coli growth was the inactivation of its acetyl-coa carboxylase enzyme [37] . other studies showed that cinnamaldehyde antimicrobial activity has a broad spectrum of action, being effective also against enterococcus faecalis, enterococcus faecium, e. aerogenes salmonella enterica and clostridium perfringens [38] . finally, with a concentration of 20 µg/ml, cinnamaldehyde was also capable to improve the bactericidal efficacy of the antibiotic clindamycin on c. difficile, significantly decreasing its minimum inhibitory concentration (mic) from 4.0 to 0.25 µg/ml [39] . in vivo, only a few studies have been conducted on cinnamaldehyde, perhaps because of its strong aggressiveness towards the mucosal epithelia. nevertheless, in animal experimental colitis, the oral administration of cinnamon eo (approx. 70% in cinnamaldehyde) at 10 mg/kg or 15 mg/kg lead to an improvement of the ecological biodiversity of the intestinal microbiota. short-chain fatty acids (scfa)-producing bacteria family, such as bacteroidaceae, were increased while intestinal helicobacter and bacteroides were reduced [40] . in broiler and duck farming, the supplementation of food with a mixture of thymol and cinnamaldehyde improved animal growth performances and positively modulated their intestinal microbiota composition, boosting healthy bacteria and reducing anaerobic coliforms and lactose-negative enterobacteria [41, 42] . thymol is effective at extremely low concentrations (as low as 300 ppm) against the growth of many species of pathogenic bacteria that colonize the human intestine, such as c. difficile, c. perfringens, propionibacterium shermanii, propionibacterium freudenreichii and bacteroides thetaiotaomicron. the negative aspect of its antimicrobial activity is that thymol was not selective, and could also have a negative impact on commensal bacteria [30] . on the other hand, eos in which thymol is a major component have clearly shown to have a wide-spectrum bactericide effects on different pathogenic species such as l. monocytogenes, e. coli, s. enterica, s. aureus, clostridium botulinum, c. perfringens, shigella sonnei, sarcina lutea, mariniluteicoccus flavus, brochothrix thermosphacta, listeria innocua, l. monocytogenes, pseudomonas putida and shewanella putrefaciens [26] . moreover, thymol seems to be effective also against the bacterial biofilm formed by β-lactamase-producing enteric bacteria [43] . it is still debated if thymol could be or not degraded by the intestinal microbiome since it was found to be not effective against fecal fermentation reactions [44] . nevertheless, in weaning piglets, thymol associated with carvacrol was capable of positively modulating their microbiota by increasing populations of the lactobacillus genus and by reducing populations of enterococcus and escherichia genera [45] . in vitro, carvacrol was showed to inhibit bacterial adhesion, invasion and biofilm development in cultured intestinal cells [46] . in the farmed broiler, treatment with carvacrol-rich eos was tested to control the pathogenic bacteria spreading inside the farms. the results of these studies demonstrated that carvacrol reduced the microbial counts of e. coli and different salmonella species in the small intestine of farmed chicken [46] . moreover, carvacrol administration to broiler chickens was capable of eliminating the intestinal presence of campylobacter spp. after 21 days of daily oral administration at 120-300 mg/kg. this effect was probably linked to the enhanced growth of bacteria of the lactobacillus genus, that were found to be increased in chicken microbiota, after carvacrol administration. e. coli growth in the cecum of chickens was found to be significantly reduced by carvacrol. for these reasons, this molecule is today the most used in organic breeding to positively modulate gut microbiota and improve the growth performance of farmed chickens [47] . in intensive breeding practices carvacrol is often associated with thymol, since there is strong evidence that the combination of the two was more effective in decreasing intestinal pathogens and increasing the growth performance of chickens [48, 49] . limonene (1-methyl-4-(prop-1-en-2-yl)-cyclohex-1-ene) is a cyclic monoterpene present in a high amount in eo of citrus fruit peels and, in smaller concentrations, in many other aromatic plant eos. limonene has widely demonstrated antimicrobial and anti-inflammatory effects in vivo. in mice, daily oral administration of 160 mg (8000 mg/kg) of orange oil, rich in limonene, modulates the mice microbiota by enhancing the relative abundance of the lactobacillus genus and reducing the presence of scfa-producing bacteria [50] . its particular ability to reduce the scfa synthesis has been exploited in a mouse model of obesity to reduce weight gain. mice fed with a high-fat diet (hfd) were treated daily with microencapsulated sweet orange oil for 15 days (2 ml of suspension of microcapsules containing 18 g/l of sweet orange eo rich in limonene). the result of this study showed a reduced body weight in treated mice, associated with a modulation of the intestinal microbiota. specifically, the bifidobacterium population was enhanced with an overall reduction of the intestinal chronic inflammation induced by the hfd, in treated mice [51] . despite the low toxicity of limonene, which would not rise concerns, it should be noted that these effects on the microbiota were obtained only with high dosages of this compound. eucalyptol (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane) is a cyclic ether and a monoterpenoid. it is the major compound in eucalyptus eo, but it can be also found in many other officinal plants eos. a recent review indicates that eucalyptus eo has extraordinary antimicrobial activities. eucalyptus eo has shown to be effective against a plethora of bacteria species and among them s. aureus, e. coli, bacillus subtilis, klebsiella pneumonia, salmonella enteritidis and p. aeruginosa [52] . nevertheless, eucalyptus eo also contains high amounts of other antimicrobial components besides eucalyptol, therefore not all of eucalyptus eo antibacterial activity can be ascribed to the presence of eucalyptol. however, literature data regarding eucalyptol antimicrobial activity are very limited, and new studies focused on this interesting compound are needed. menthol (5-methyl-2-(propan-2-yl)cyclohexan-1-ol) is a chiral alcohol and the main molecule present in cornmint and peppermint eos. it has been well known for its use in foods as a cooling and minty-smell aroma. many in vitro studies, reviewed by kamatou and coworkers [53] focused on its antibacterial activities. interestingly, in vitro, menthol was capable to drastically decrease c. difficile viability at 18.8 mg/ml, with a dose-dependent effect. its mechanism of action seems to be due to the significant leakage of cellular atp induced by menthol in this pathogenic bacterium [54] . fungi were reported to represent about 0.1% of all the microorganisms present in the gastrointestinal tracts. maybe also for this reason, despite the presence of fungi in the intestine has been known for many years, in depth studies of the human mycobiome were only recently performed [55] . humans are hosts to a wide number of fungi species that coexist with the other microorganisms into the gut in a complex ecological relationship of interdependence [56] . together with bacteria, fungi contribute to the modulation of the intestinal immune system [57] . many of them have a clear pathogenic potential even if, physiologically, they are commensals in our bodies. only in some specific conditions their overgrowth can lead to well-known mycosis. the best known fungal pathogen of humans is certainly candida albicans, which is a normal component of the gut mycobiota but may causes candidiasis in case of its intestinal and vaginal overgrowth [58] . an altered intestinal mycobiota has also been observed in other human pathological conditions, such as ibs [59] , inflammatory bowel disease (ibd) [60] and also autism-spectrum disorders and rett syndrome [61] . since human mycobiome is altered in some diseases, perhaps contributing to their pathogenesis, the therapeutic manipulation of the mycobiome could be a useful approach to treat and/or prevent these diseases [62] . eos antimycotic activities are characterized by a broad spectrum of actions [63] . c. albicans is responsible for the majority of fungal infections in humans and is certainly the most studied mycobiota pathogen. the overgrowth of c. albicans is usually controlled by the immune system of the host; however, in particular conditions such as in immunocompromised patients, this microorganism may cause severe infections [64] . for this reason, c. albicans is one of the main target for studies focusing the antifungal effect of eos and their single molecules. the antifungal activities of eo obtained from thymus vulgaris, citrus limonum, pelargonium graveolens, cinnamomum cassia, ocimum basilicum, and eugenia caryophyllus have been evaluated against clinical isolates of c. albicans and candida glabrata. all of these eos exhibited both fungistatic and fungicidal activity toward these two candida species, but cinnamon oil demonstrated the highest activity [64] . since the most represented active compounds of cinnamomum eo is cinnamaldehyde, many studies have been addressed to analyse in depth its activity against c. albicans. the mic 90 at which cinnamaldehyde has been shown to inhibit c. albicans growht ranged from 125 to 450 µg/ml [65] . limonene has shown to possess strong antifungal properties [66] and in particular an excellent anti-candida activity. a recent study analyzed the efficacy of this compound against the growth of c. albicans isolates, including fuconazole-resistant strains. in this study, the in vitro growth of 35 clinical isolates of c. albicans were completely inhibited at doses ranging between 5 mm and 20 mm of limonene. furthermore, limonene inhibited the adhesion, development and maturation of the c. albicans biofilm with 50% of inhibition occurred at doses between 1.8 and 7.4 mm. at the dose of 20 mm, limonene was also capable to degrade 70% of mature biofilm [67] . mentha eos obtained from m. piperita, m. spicata, m. longifolia, m. pulegium, m. cervina, and m. suaveolens, have demonstrated good antimycotic activities against different fungi genera, including candida [68] . menthol and (+)-carvone are the major components of peppermint eos and both exhibited strong antifungal activity in vitro. these activities were evident only at a relatively high doses: peppermint oil inhibited the in vitro growth of c. albicans at 20 mg/ml in agar dishes, whereas caraway oil showed inhibitory effects at lower doses, in the range 5-10 mg/ml [69] . a patented peppermint and caraway oils formulation, called menthacarin ® , was tested in an ibs animal model, showing to be effective in alleviating abdominal pain in rats via mycobiome modulation, suggesting a possible role of mycobiota dysbiosis in the etiopathogenesis of ibs [70] . thymus vulgaris eo has also shown to be effective against fungi pathobionts capable to infect humans. a study on dermatophyte, fungi that can cause superficial infections of the skin, and on aspergillus, fungus genera that can cause respiratory infections, reported mic values for thymus vulgaris eo ranging from 0.16 to 0.32 µl/ml. higher mic values, between 0.32 and 0.64 µl/ml, were reported for candida spp. the antifungal activity of this eo has been attributed to its two major components: thymol and carvacrol, that accounted respectively 26% and 21% of thymus vulgaris eo [70] . both these phenolic compounds seem to act by disrupting the fungal cell membranes [27] . an interesting study evaluated the antifungal activity of thymol in comparison with miconazole, a classical antifungal medication, against c. albicans growth and biofilms formation. the results of this study demonstrated that these two molecules were equally effective against c. albicans with no statistically difference between the two treatments, confirming an extraordinary antimycotic effect of thymol. however, relatively higher concentration was necessary for thymol, with a mic that corresponded to 350 µl/ml vs. 75.15 µl/ml for miconazole [71] . thymol antifungal activity was tested against other candida species, and it showed to be effective also against c. tropicalis. [72] . clove eo has been traditionally used in dentistry for its anesthetic and antimicrobial activities [73] . its anti-fungal action has been attributed to eugenol, the major clove oil molecule. a recent study indicated that clove eo, at concentrations that ranged between 0.03% and 0.25% (v/v), inhibited the biofilm formation in many candida species, grown on different substrates [74] . for what the mechanism of action concerns, eugenol was able to cause permanent injury to the cell membranes of c. albicans and morphological alterations to its cell wall [27, 75] . the activity of eugenol against c. albicans was multitarget and also targeted enzymatic pathways, such as the h + -atpase in mitochondria [76] . eugenol treatment also induced an overall oxidative damage to the fungal cell (lipid peroxidation), and these multiple damages may finally lead to cell death [77] . the antiviral activity of eos has been established for different viruses, and it can be directed against the viral particle or against their intracellular replication process [78] . several studies demonstrated that the herpes simplex viruses, type 1 and 2 (hsv-1 and hsv-2), influenza a virus and coronavirus may be sensitive to eos and to their single molecules [79] [80] [81] . it is interesting to observe that many hsv strains, resistant to synthetic antiviral drugs, are instead sensible to eos and to their components. that is probably because they have a multitarget mechanism of action compared to specific drugs that usually target single virus component or single metabolic pathways. for this reason, it is reasonable to expect that antiviral drugs and eos could act in synergy [78] . bovine viral diarrhea virus (bvdv) is considered a good animal model for the human hepatitis c virus. this virus has been successfully treated with basil eo and single monoterpenes that are major components of this eo: camphor, thymol and eucalyptol. to perform the tests, basil eo and monoterpenes were used at a concentration of 64 mg/ml. results obtained in this in vitro study showed that while the basil eo did not demonstrated to have significant antiviral activities, its single monoterpenes significantly decreased bvdv infectivity on bovine kidney cells, acting directly on the viral particle [82] . these results are interesting because they suggest that for specific antimicrobial applications, it is much more useful to use individual components of eos rather than eos as such. since the antimicrobial and antiviral activity of single eo molecules are multitarget activities, it is very important to design new study focused on single eo constituents and not on blends of different eos, that are very difficult to analyze and to replicate. antiviral properties of carvacrol have been demonstrated on nonenveloped murine norovirus (mnv), a good model for the human norovirus. carvacrol 0.25% and 0.5% (v/v) reduced virus propagation on a murine monocyte cell line, demonstrating its ability to inactivate mnv acting firstly on the viral capsid and afterwards directly on its rna. this underlines the efficacy of carvacrol as a natural surface disinfectant and as a food preservative to control human norovirus, which are the most frequent cause of food-borne viral diseases in humans, causing non-bacterial gastroenteritis. [83] . to date, no study has been performed to understand the impact of eos on the intestinal virome. the main physiological viral component of the gastrointestinal tract is represented by prophages or phages [84] . the bacteriophage component is mainly composed by temperate virus of the caudovirales order, but most of the detected viral sequences in human gut virome could not be attributed to known viruses [85] and to date it is estimated that the number of viruses in human stools is up to 10 9 per gram [86] . despite this, it is clear that eos may impact the intestinal virome composition by modulating all the microbiota components, it could be really difficult to understand the direct impact of eos on the intestinal viruses and the consequences of this modulation on the intestinal ecology. to date, there is some evidence that eos may be effective against different virus replication, but there are still not enough data to predict what could be the impact of eos on viral infectious diseases of the gastrointestinal tract. the presence of a very complex microenvironment makes it difficult to understand if eos can really act against the pathogen virus particles or if they reach mucosa cells only after the infection. since eos are potentially able to act both on bacteria and viruses, in pathological conditions it could be difficult to understand the real targets of these compounds. for example, it has been demonstrated that norovirus persistent infection can be sustained by gut bacteria dysbiosis, and the use of antibiotics in infected mice is able to counteract the viral replication [87, 88] . nowadays, colorectal cancer (crc) is one of the most common tumours worldwide. it represents the second cause of cancer death in europe, even if mortality is decreasing due to the new screening programs and improvement in therapies [89] . the aetiology of crc is not only related to genetic and environmental factors but also to gut microbiota and chronic colonic inflammation. genetic factors include mutations in genes regulating enterocyte cell growth, proliferation, differentiation or cell cycle control or polymorphisms of several proteins involved in dna repair and transcription [90] [91] [92] [93] . among the environmental factors, the most important seems to be the high consumption of red meat, smoking and drinking alcohol in huge amounts [94, 95] . the involvement of the gut microbiota in crc is related to the production of noxious metabolites by bacteria, such as secondary bile acids, polyamines or genotoxins [96] . these metabolites may cause to colonocytes oxidative stress, direct dna damage or induce inflammation [97] . chronic inflammation condition, such as those linked to ibd, are also recognised as a risk factors for crc development [98] . crc manifestation can be sporadic or have a familial predisposition, that's the case of familial adenomatous polyposis (fap) and other syndromes like peutz-jeghers, serrated polyposis and lynch [99, 100] . classical crc therapies include surgical treatments, radiotherapy or chemotherapy [101] , which are associated with important side effects and with the development of drug resistance [102, 103] . recently new pharmacological approaches have been successfully developed for crc, including biological drugs, aimed at the treatment of previously diagnosed cancers [104] . despite the presence of different therapeutic strategies for crc, we must not forget the potential of natural anticancer substances, especially in the prevention of a neoplasia which requires long times to transform from a benign dysplasia to a malignant adenocarcinoma. several eos and their single components have been tested in vitro and/or in vivo by using crc models and have been proved to be valid antitumoral molecules for this cancer. carvacrol was tested on different crc cell lines (htc-116 and lovo), where it was determined the reduction of proliferation and cell cycle arrest in g2/m phase, associated with the reduction of cellular invasion and migration proprieties [105] . geraniol has shown a strong cytotoxic effect on colo-205 cell line [106] but it was not able to induce apoptosis on caco-2 cell line, where it only showed a cytostatic effect, by arresting their cell cycle in s phase [107] . this demonstrate how the same compound may not have the same effect on different cellular crc models. geraniol also demonstrated its anticancer property against the regulation of polyamine metabolism, that is another target of cancer therapies [107, 108] . in different crc cell lines, geraniol has been shown to downregulate the ornithine decarboxylase (odc) and to upregulate s-adenosylmethionine decarboxylase (adometdc), two enzymes involved in polyamine catabolism and elimination [107] . thymol has shown cytotoxic effect against htc-116 cell line by inducing ros production and dna damages. it also induced cell-death by affecting cancer cell mitochondrial pathways [109] . on the other hand, thymol, geraniol, nerolidol, and methyleugenol, at low doses, have demonstrated to have genoprotective effects against oxidative and dna methylation damages in ht-29 cell line [21] . these data underline the importance of the effective dosage of these substances that reaches the colon, since all of them are subject to intestinal absorption. cinnamaldehyde have been tested on several crc cell lines and, like others eo components, it caused the inhibition of proliferation and the induction of apoptosis (by pi3k/akt inhibition and by increasing bax/bcl-2 ratio) associated with a reduction of invasion and migration capability of sw-480, hct-116 and lovo cells (by increasing e-cadherin levels and downregulating mmp-2 and mmp-9 enzymes) [110] . for these reasons, cinnamaldehyde has been used for the development of an aspirin-like drug for the prevention of crc [111] . cinnamaldehyde has also been associated with camptothecin, a hydrophobic anticancer drug, and then incorporated in polymeric micelles to obtain a controlled release system based on ph-gradients. these micelles have shown to induce apoptosis and generate intracellular ros with synergistic anticancer effects between cinnamaldehyde and camptothecin both on in vitro and in vivo models of sw-620 human colon tumour cell or bearing mice [112] . so, the anticancer activities of eos compounds can reduce drug resistance and sensitize cancer cells to traditional chemotherapeutic agents, by acting synergistically with them. geraniol has been reported to sensitize caco-2 cell line to 5-fluorouracil (5-fu), by altering cell membrane potentials and facilitating the uptake of 5-fu [113, 114] . the synergistic effect of geraniol and 5-fu has been investigated both in vitro and in vivo. geraniol potentiates 5-fu growth inhibition activity on sw-620 and caco-2 cell lines by downregulating the thymidylate synthase and thymidine kinase, two enzymes related to 5-fu cytotoxicity. these data have been confirmed in vivo on nude mice grafted with the human colorectal cells tc-118 [115] . in a similar manner thymoquinone, a compound of nigella sativa eo, demonstrated-in association with doxorubicin-an improvement of drug-antineoplastic activities on ht-29 cell line [116] . thymoquinone also sensitized colo-205 and htc-116 cancer cells to cisplatin and increased cancer cell death by suppressing nf-kβ [117] . finally, it has been shown that thymoquinone was capable to sensitize resistant lovo colon cancer cells to the drug irinotecan by affecting erk1/2 pathway and increasing the membrane permeability and the autophagy process [118, 119] . β-caryophyllene is a natural bicyclic sesquiterpene found in many eos, particularly in clove oil. it has been studied in association with paclitaxel and doxorubicin on dld-1 and caco-2 cell lines, respectively. it facilitated the passage of paclitaxel through the plasma membrane, increasing its anticancer activity [120] . moreover, β-caryophyllene treatment induced an intracellular accumulation of doxorubicin that increased its anticancer activity [121] . β-caryophyllene has also been involved in the regulation of glucose homeostasis in crc cells, regulating genes involved in glycolysis and cell growth and finally leading to cell growth suppression and apoptosis [122] . taken together, these results suggest that there is a real wide possibility of using eos or their individual compounds in crc prevention, but also in reducing the doses of classic chemotherapy drugs adopted to treat crc patients. this would consequently reduce the side effects of chemotherapy with a real benefit for patients during anticancer therapy but without decreasing its therapeutic efficacy. considering that the development of crc can be determined by the presence of colonic chronic inflammation for a long time, the efficacy of these natural compounds is certainly maximum in terms of crc prevention, in all subjects at high risk of developing this cancer, both for familiar history or for pre-disposing pathologies, such as ibd or fap. in this context and within long-term therapeutic preventive strategies, it has to be stressed eos multi-target properties, that makes the development of resistant tumour cells very difficult. eos, but especially their single molecules, are effective multitarget modulators of the intestinal physiology and pathology. their use to date has been limited due to several factors that include testing complex mixtures that did not allow identifying the individual active components, the difficulty of releasing these compounds in the affected intestinal tract and their toxicity and aggression on the mucous membranes which complicates their in vivo administration. most eos have very strong, sometimes unpleasant flavors, and in several cases they are also aggressive towards the oral, esophageal and gastric mucosa. administration in controlled release formulations therefore often becomes a necessity. by using normal pharmacological forms such as tablets, capsules or soft gels it is possible to obtain gastro-resistant pharmaceutical forms. once reached the intestine, the chemical compounds contained in the oes are assimilated more or less quickly, with different bioavailability, depending on their chemical structure and pharmacokinetics. geraniol rapidly crosses the enterocytes and, once reaching the bloodstream, has shown a half-life of 12.5 min with a pseudo first-order kinetics [5] . on the contrary, eugenol is rapidly absorbed, but has shown a half-life of 18.3 h in blood and could accumulate after repeated daily administrations [123] . cinnamaldehyde has shown a half-life of 6.7 h. however, the 60% of cinnamaldehyde is oxidized to cinnamic acid rapidly [124] . carvacrol is only partially absorbed in the intestine and has shown to reach low concentration in plasma with a peak after 2 h of oral administration [125] . d-limonene is only partially absorbed by enterocytes and has shown a half-life of 3.20 h in plasma [126, 127] . similar behavior has been found for β-caryophyllene, that has shown a half-life of 4.07 h in plasma [128] . thymol is absorbed quickly in the gut, and it is present in plasma only as thymol sulfate, that reach a considerable concentration after 20 min, with an half-life of 10.2 h [129] . the current scientific knowledges regarding their activities against oxidative stress and their ability to modulate the microbiota and the intestinal inflammation are more than enough to plan clinical trials on humans and provide evidences for their use as therapeutic agents. the strong multitarget antitumor activity of some molecules present in eo make them potentially very effective therapeutic strategies against crc, also in combination with chemotherapies already in use. however, the maximum potential of these compounds seems to be expressed in the prevention of crc, inflammation and intestinal dysbiosis. table 4 summarize the main effects of oes divided according to their main activity in the intestine and with the indication of the individual compounds mainly responsible for the action. increasing antineoplastic effect of doxorubicin, increasing cell death by suppressing nf-kβ in association with cisplatin, induction of autophagy in association with irinotecan [116] [117] [118] [119] n.a. β-caryophyllene antitumoral effect in association with chemotherapeutic agents, regulation of glucose homeostatis (in vitro) increase of anticancer activity of paclitaxel and doxorubicin regulation of genes involved in glycolysis and cell growth, induction of apoptosis [119] [120] [121] a limit to their use is the need of controlled release systems that target these molecules in the intestine area where their action is required. in fact, all these compounds are absorbed in the small intestine, some of them very quickly, such as geraniol, while others with less efficient transport mechanisms, such as limonene [5, 123] . nevertheless, possibilities for a controlled release of these molecules already exist, and it has already been proven that they are effective in humans to obtain a controlled release [8] . further in vivo and clinical studies are necessary to understand their bioavailability, pharmacokinetics and mechanism of actions. unfortunately, the low cost that these eos have on average, and their non-patentability, make them little or not at all interesting for pharmaceutical industries, making missing the sponsors for the clinical studies necessary to finally validate their therapeutic efficacy in many different intestinal pathologies of the large bowel, such as inflammation, colitis, dysbiosis and crc. metabolic engineering strategies for enhancing the production of bio-active compounds from medicinal plants antimicrobial, antioxidant, and immunomodulatory properties of essential oils: a systematic review oxidant signals and oxidative stress metal dyshomeostasis and their pathological role in prion and prion-like diseases: the basis for a nutritional 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inhibits proliferation and induces apoptosis in human colon cancer cells. anti-cancer drugs geraniol and geranyl acetate induce potent anticancer effects in colon cancer colo-205 cells by inducing apoptosis, dna damage and cell cycle arrest geraniol, a component of plant essential oils, inhibits growth and polyamine biosynthesis in human colon cancer cells polyamine metabolism and gene methylation in conjunction with one-carbon metabolism thymol elicits hct-116 colorectal carcinoma cell death through induction of oxidative stress cinnamaldehyde affects the biological behaviour of human colorectal cancer cells and induces apoptosis via inhibition of the pi3k/akt signalling pathway novel cinnamaldehyde-based aspirin derivatives for the treatment of colorectal cancer dual acid-responsive micelle-forming anticancer polymers as new anticancer therapeutics perturbation by geraniol of cell membrane permeability and signal transduction pathways in human colon cancer cells geraniol, a component of plant essential oils, sensitizes human colonic cancer cells to 5-fluorouracil treatment geraniol, a component of plant essential oils, modulates dna synthesis and potentiates 5-fluorouracil efficacy on human colon tumor xenografts combinatorial effects of thymoquinone on the anti-cancer activity of doxorubicin thymoquinone chemosensitizes colon cancer cells through inhibition of nf-κb thymoquinone induces caspase-independent, autophagic cell death in cpt-11-resistant lovo colon cancer via mitochondrial dysfunction and activation of jnk and p38 inhibition of nf-κb and metastasis in irinotecan (cpt-11)-resistant lovo colon cancer cells by thymoquinone via jnk and p38 potentiating effect of β-caryophyllene on anticancer activity of α-humulene, isocaryophyllene and paclitaxel the influence of sesquiterpenes from myrica rubra on the antiproliferative and pro-oxidative effects of doxorubicin and its accumulation in cancer cells effects of beta-caryophyllene on arginine 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experimental colon carcinogenesis carvacrol exhibits anti-oxidant and anti-inflammatory effects against 1, 2 dimethyl hydrazine plus dextran sodium sulfate induced inflammation associated carcinogenicity in the colon of fischer 344 rats this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license the authors thank alberto sardo for illuminating us on the infinite potential of essential oils. the authors declare no conflict of interest. key: cord-344902-bittqpyo authors: scott, jennifer; abaraogu, ukachukwu o.; ellis, graham; giné-garriga, maria; skelton, dawn a. title: a systematic review of the physical activity levels of acutely ill older adults in hospital at home settings: an under-researched field date: 2020-10-15 journal: eur geriatr med doi: 10.1007/s41999-020-00414-y sha: doc_id: 344902 cord_uid: bittqpyo purpose: the purpose of this review was to identify, evaluate and synthesise existing evidence reporting the physical activity levels of acutely ill older patients in a ‘hospital at home’ setting and compare this to patients with similar characteristics treated in a traditional hospital inpatient setting. functional changes and any adverse outcomes due to physical activity (e.g. falls) in both settings where pa was reported or recorded were also evaluated as secondary outcomes. methods: a search strategy was devised for the medline, cinahl, amed, pedro, ot seeker and cochrane databases. search results were title, abstract and full-text reviewed by two independent researchers. data were extracted from included articles using a custom form and assessed for quality and risk of bias using the appraisal tool for cross-sectional studies. results: no studies set in the hospital at home environments were identified. 16 hospital inpatient studies met the criteria for inclusion. older patients managed in inpatient settings that would be eligible for hospital at home services spent 6.6% of their day active and undertook only 881.8 daily steps. functional change was reported in four studies with both improvement and decline during admission reported. conclusion: there is a lack of published research on the physical activity levels of acutely-ill older adults in hospital at home settings. this review has identified a baseline level of activity for older acutely ill patients that would be suitable for hospital at home treatment. this data could be used as a basis of comparison in future hospital at home studies, which should also include functional change outcomes to further explore the relationship between physical inactivity and functional decline. electronic supplementary material: the online version of this article (10.1007/s41999-020-00414-y) contains supplementary material, which is available to authorized users. hospital at home (hah) is a model of healthcare delivery which provides an alternative to hospitalisation by delivering acute-level hospital services in a residential setting [1] . the hah care model has increased in prevalence in recent years, with well-established programmes providing services in western europe, north america, brazil, australia, israel and south east asia [2] . home-hospitalisation has also been advocated during the recent covid-19 pandemic as a means of increasing bed capacity, facilitating quarantine and reducing disease transmission to vulnerable groups [3] . research interest has also been growing, with a more than sixfold increase in hah-related citations between 1999 and 2019 [4] . a recent systematic review found that hah may be a clinically effective alternative to inpatient care for some older, acutely-ill medical patients [5] . furthermore, it suggested hah treatment may pose less risk of physical functional decline to patients than the traditional ward-based inpatient environment [5] . functional decline is a known adverse effect of hospitalisation, affecting between 30 and 56% of older inpatients between admission to hospital and discharge [6] [7] [8] [9] , manifesting as a loss of muscle mass, strength, physical function and/or ability to perform basic activities of daily living such as dressing, eating and maintaining hygiene and continence [10] [11] [12] . physical inactivity while hospitalised, combined with older age, are predictors of functional decline [13] . hospitalised patients are highly inactive, with acute medical and surgical inpatients spending between 93 and 98.8% of their time sitting or lying [14] , and older patients spending as little as 76mins per day in an upright position [15] . recently published draft recommendations on physical activity for inpatients have emphasised the importance of incorporating opportunities for physical activity into the daily care of older adults to improve clinical outcomes, focusing on function, independence and activities of daily living [16] . however, there are many institutional barriers to physical activity in hospital including lack of staff support, tethering to medical devices, lack of assistive devices, and unfamiliar surroundings, as well as a fear of injury [17] . treatment in a less restrictive home environment may overcome such barriers, providing more opportunity for patients to continue to perform regular activities of daily living [5] , thereby lessening the risk of functional decline. this review sought to investigate the hypothesis that older, acutely ill patients treated in a hah setting may be more active than hospital inpatients with similar characteristics. the aim was to identify, evaluate and synthesise primary research studies reporting cumulative physical activity levels in these populations and, where reported, evaluate reports of functional decline or adverse effects resulting from physical activity during admission. as will be reported, no studies conducted in hah treatment settings were identified, and functional change outcomes were largely absent. the review protocol was developed in accordance with preferred reporting items for systematic review and meta-analysis protocols (prisma-p) [18] guidelines and registered with the international prospective register of systematic reviews (prospero, registration number crd42019138822) [19] . the review followed the guidelines set out in the cochrane handbook for systematic reviews of interventions [20] where applicable and complies with the prisma statement [21] for the conduct and reporting of systematic reviews. a comprehensive search strategy was developed in accordance with the cochrane recommendations for health care review [22] and reviewed by a specialist medical librarian. the search was initiated in july 2019 and updated 19 january 2020 to ensure currency. search terms and appropriate synonyms were chosen in alignment with the research objective and combined using boolean operators, subject headings, truncations and wildcards where appropriate. filters limited results to peer reviewed, english language, human studies with available abstracts published since 1980. all study designs were acceptable. the databases medline (ovid interface), central, cumulative index to nursing and allied health literature (cinahl), allied and complementary medicine database (amed), pedro and otseeker were chosen as the most relevant to the subject matter. the full search strategies with database-specific syntaxes for all sources are included in online resource 1. once key papers were identified, reference lists were handsearched and subject experts were approached to identify any further resources. 'grey' literature including conference abstracts, reports, unpublished data and dissertations were not included. multiple publications using the same participant dataset were excluded and the most comprehensive or recent publication used. setting studies set in either an hah or acute medical inpatient environment were included, studies did not have to compare both groups. hah was defined as 'a service that provides acute, hospital-level care by healthcare professionals in a home context for a condition that would otherwise require acute hospital inpatient care' [1] . an acute inpatient setting was defined as 'a hospital (private or public) providing 24-h care for people who are unwell and had an unplanned admission' [23] . as hah is designed to treat acute episodes of transient rather than chronic medical illness [5] , studies set in non-medical or non-acute environments such as palliative care, respite, rehabilitation, mental health, long-term care or residential nursing home facilities were excluded. studies concerned with post-discharge hah services (e.g. 'step-down' hah), were also excluded, as the focus of the research project is hah as an alternative to hospital admission for the preservation of physical function. participants studies involving patients aged 60 and over diagnosed with an acute-onset medical condition that would fall within the scope of a hah service were included. hah services predominantly manage non-surgical, non-critical conditions such as infection, acute exacerbations of cardiac and respiratory conditions, haematological and metabolic disturbances, and acute kidney injury [1] . certain conditions are not appropriate for management in a home setting such as those requiring surgery (e.g. acute coronary syndromes, orthopaedics), critical care or advanced diagnostics and interventions (e.g. stroke). to ensure that intervention and comparison populations were similar, studies containing these large numbers of patients with such conditions were excluded unless these participants could be discounted from the results. a margin of ≤ 10% of patients under 60 and ≤ 10% with excluded conditions was allowed. where numbers exceeded this margin, or other pertinent information was required, study authors were approached via email on up to 2 occasions to request abridged results. where a custom dataset was provided, this was used in analysis over the published dataset. intervention and comparator the intervention of interest was treatment in a hah setting compared to standard inpatient acute care. as this review aimed to establish if there are differences in the cumulative activity levels of patients in each setting, trials of other interventions to increase patient activity such as exercise programmes or physiotherapy sessions over and above usual care were not suitable for inclusion unless the physical activity levels of the control group were available, as the intervention group would not be representative of the general older acute population. outcome the primary outcome measure was the cumulative level of pa performed by patients receiving standard medical care in a hah and/or inpatient setting. it was decided a priori that acceptable measures would include objective methods, such as activity monitor data, or subjective methods, such as direct observation, self-reported instruments or questionnaires. changes in functional independence (e.g. activities of daily living, dependent walking) and physical performance (e.g. handgrip test, timed up and go) from admission to discharge, as well as any adverse effects reported as a consequence of physical activity (e.g. falls) were selected as secondary outcomes. the inclusion and exclusion criteria are summarised in table 1 . literature search results and bibliographic records were exported into refworks to facilitate deduplication and screening of titles and abstracts. articles meeting the inclusion criteria were then subjected to full-text appraisal. all records were reviewed by the lead researcher (js) and independently second-reviewed by another (ds, ua, mg or ge). the decision for inclusion or exclusion was recorded along with reasons for exclusion. where there was disagreement between reviewers on inclusion at any stage, a third reviewer was consulted. sixteen articles were selected for inclusion in the review. this process for identifying these is documented in the prisma flowchart [21] below ( fig. 1 ). the process of data extraction was performed using a custom template which was developed and piloted to extract: (1) data relevant to the research question, and (2) data required to perform a quality appraisal and risk of bias assessment using the appraisal tool for cross-sectional studies (axis) [24] (data extraction table: online resource 2, axis appraisal: online resource 3). the axis tool comprises 20 questions and considers study design and reporting quality in addition to the risk of bias when appraising research studies [25] . the data extracted were spot-checked for accuracy by the review team (ds, ua, mg or ge). where studies reported results for participants that were excluded from this review (e.g. surgical, non-geriatric) these were separated and excluded from the analysis. separate datasets were requested and received from karlsen [26] and valkenet [27] containing only participants that met the inclusion criteria. the physical activity outcomes of the studies were grouped according to their method of measuring physical activity levels and reporting format. in accordance with duvivier [28] , standing and slow walking have both been categorised as physical activity and grouped together into 'active time' for the purposes of analysis. time spent sitting or lying down, including sleep time, has been classified as 'non-active' time. this classification allowed 3 categories to emerge; (1) active time recorded over 24 h, (2) active time recorded over variable timeframes, and (3) physical activity as step count. the percentage of time spent actively was selected as a common scale to enable comparison of data across the studies. studies using step count as a measure of physical activity were reported separately. results reported in minutes were converted into a percentage of 24 h. median and interquartile ranges were converted into mean values using the formula devised by wan [29] to allow results to be summarised as pooled averages. summary independent t-tests were used to examine whether physical activity or step count differed significantly from the pooled averages when grouped by medical condition or studies at lower risk of bias. analyses were performed using spss v26, p < 0.05 was considered significant and 95% confidence intervals are reported. study characteristics no suitable hah studies were identified. all 16 included studies were conducted in single-site [21] acute inpatient hospital environments. the studies were published between 2006 and 2019, and the majority (n = 13) were cross-sectional observational designs aiming to establish the physical activity levels of patients as a primary outcome. this design is consistent with the nature of the research question, which does not aim to evaluate the efficacy of an intervention. of the remaining three studies, two were validation/agreement studies [27, 30] , and one was a randomised controlled trial (rct) [31] . participants most studies concerned general acute medical patients (n = 11, mean sample size 114, range . five studies were exclusively concerned with patients with specific conditions; two each reported physical activity levels of patients with acute exacerbations of chronic obstructive pulmonary disease (mean sample size 13.5, range 10-17) [30, 32] , and heart failure (mean sample size 36, range 27-45) [33, 35] and whilst one reported on patients with mixed medical conditions plus mild-moderate cognitive impairment (sample size 20) [34] . primary outcome all included studies assessed physical activity levels using objective accelerometer-based methods, except belala [34] who used behavioural mapping. valkenet [27] also performed behavioural mapping in addition to accelerometery (dynaport movemonitor). a variety of monitoring devices and algorithms were used, with the activpal (pal technologies, glasgow, uk) being the most commonly used device in studies concerned with posture (5 uses), and the stepwatch activity monitor (modus health, washington, us) used most frequently for step count (4 uses). the validity of the methods used was reported by most studies, except for the mediwalk pedometer (terumo, japan), used by ueda [31] . the range and validity of outcome measures used is available in online resource 4. the included studies were assessed for risk of bias using the axis tool [24] (online resource 3) which was deemed appropriate due to the high proportion of observational studies identified. there is an inherent risk of bias in descriptive, observational study designs, which rank low on evidence hierarchies, however, a well-designed and conducted crosssectional study can be of some evidential value [35] . the axis tool prompts consideration of selection, instrumentation and reporting bias as well as reporting and study design quality. it was also suitable for the evaluation of the methodology used to acquire and report physical activity levels in the rct included in this review [31] . a domain-based risk of bias assessment indicates a low risk of instrumentation and reporting bias, with adequate measurement and reporting of physical activity levels, however, there is a high risk of selection bias within the identified research (fig. 2) . the studies that performed better in the analysis [34, [36] [37] [38] gave greater consideration to reporting information on non-responders (patients that were eligible for inclusion but declined to participate). in terms of quality assessment, overall reporting quality was high, however, study design considerations were less well evidenced, with a broad lack of consideration of sample size, and frequently vague reporting of ethics or consent protocols. active time recorded over 24 h the level of inpatient physical activity reported as a percentage of 24 h could be established in seven studies (table 2) . when averages were pooled, the mean proportion of time spent active was found to be 6.6% ± 6.3 (range 3.8-8.3%). active time recorded over a variable timeframe three studies collected results over shorter, variable timeframes (7-12 h periods), during waking hours, and with different populations and measurement techniques (accelerometery and behavioural mapping), which precludes pooling of results, however, it can be seen that daytime-only levels are higher than the mean for 24 h results, ranging from 8.8 to 13.9% (median 10.7%) ( table 3) . physical activity as step count eight studies used pedometers or accelerometers to record 24 h step count as a measure of physical activity ( functional change between admission and discharge was reported in 4 studies, the results extracted are summarised in table 5 . as will be discussed, the reported outcomes from these studies were highly heterogenous in terms of tools used, data collection protocols and presentation of data, such that no summative conclusions on of the impact of differing physical activity levels on the incidence of functional decline could be drawn from the data. adverse effects occurring during the period of monitoring were poorly reported, with only four studies reporting this outcome; two advised there were no adverse effects [34, 38] and two reported one death (unrelated to physical activity) [31, 32] during the course of their research. sub-group analyses were performed comparing studies at lower risk of bias (according to axis appraisal) and concerning only one medical condition to the overall physical activity and step count results. both sub-group analyses found no significant difference in results comparing these devices to the overall results (table 6) , indicating the general results are an accurate representation of pa levels. the aim of this review was to identify, evaluate and synthesise the evidence on the physical activity levels of acutely ill older patients undergoing treatment in an hah vs inpatient setting. no hah studies of older adults could be identified, representing a significant gap in the literature surrounding this treatment model. despite the lack of hah research in this field, this review has provided useful data on the baseline physical activity levels that could be expected for patients suitable for treatment in a hah model of care: when monitored for 24 h/day, such patients spend on average 6.6% of the time active, and walk as few as 881.8 steps per day. these findings are consistent with other research on hospitalised older adults, despite the strict hah-specific inclusion/exclusion criteria applied. baldwin [14] reviewed 42 studies reporting the activity levels of acutely admitted medical and surgical adult patients, and found patients spent between 93% and 98.8% of their entire stay sitting or lying, and that the majority of studies reported a daily step count of < 1000. similarly, fazio [40] , in a systematic review of standing/ walking activity in medical inpatients, found that patients were active for 70 min per 24 h (4.9% of the time). the baseline pa values provided in this review may be suitable for use as an inpatient comparator value in future hah pa studies. the low levels of activity reflected in our findings can result in functional decline, however, in our results only four of the studies measuring physical activity also measured functional change. this represents a missed opportunity to further explore correlations between physical activity and functional decline that should be addressed in future pa studies in hospitalised and hah patients. where functional changes were reported there was high heterogeneity in results between studies. agmon [41] established that walking less than 900 steps when hospitalised was strongly associated with functional decline in older adults. both ueda [31] and villumsen [39] reported a mean step count below this threshold, and while both reported results using the barthel index, measurements were taken at different points in the studies and the results were presented differently: ueda [31] reported the change in mean score, while villumsen [39] reported the percentage of participants who improved. in all, six different metrics were used in the four studies reporting functional change, with high variability in measurement tools (see online resource 4), data collection protocols and reporting formats, precluding meaningful synthesis of the results. assessing physical function in acutely ill older inpatients who may present with a wide range of medical conditions and functional levels is undoubtedly challenging, and research is ongoing to identify the most feasible tools to use in this patient group [42] . a consensus-driven core outcome set for studies of functional performance in either older or hospitalised populations has yet to be developed and should be a research priority to allow evaluation and meta-analysis of the findings of studies in this field. placing the findings of this review in the wider context of physical activity research is challenging again due to substantial differences in the methods and outcome measures used. the techniques most frequently utilised in the studies in this review (24 h recording, positional accelerometery) rarely feature in population or community-based research. including night-time activity is likely to present a more accurate picture of all activity undertaken, especially in a hospital setting where circadian rhythms may be disrupted [14] , but will result in lower average activity levels than studies of day-time pa or sedentary behaviour only. this is evident in the results for the three studies that conducted monitoring over a shorter, daytime, timeframe (table 3 ) which found physical activity ranged from 8.8 to 13.9% of the monitoring period. as a result of these different outcome measures, recording periods and a lack of objectively established normative values for the 24-h physical activity of healthy free-living older adults, it is challenging to establish how much activity drops when hospitalised. however, as the continuous objective monitoring of research participants becomes easier and cheaper with developments in accelerometery and wearable digital technology, it may be the case that normative values for pa in free-living older adults can be established. this would allow more accurate evaluation of the extent to which normal pa is impeded by acute illness, in both hah and inpatient settings. a strength of this review is that it followed a systematic approach following cochrane guidelines where applicable [20] and was reported in accordance with prisma statement, which reduces the risk of bias. a possible limitation of this review is its high specificity arising from highly refined inclusion and exclusion criteria. this led to some potentially relevant articles being excluded. for instance, two promising rcts were identified during the literature search and selection process which found that adult hah patients may around 2.6 times more active than inpatients [43, 44] , however, these studies were excluded as it was not possible to isolate the results for participants aged over 60 years-only. a further limitation of this review is the high risk of bias present in the studies identified, which may limit the representativeness of the findings. physical and functional decline, caused in part due to inactivity during hospital admission, can have a considerable impact on an older patient's health and ability to remain independent on discharge. hah may offer a treatment environment that preserves and facilitates physical activity in older patients, however, it has been demonstrated in this review that there is a lack of research evidence to confirm this. this review has provided an indication of the baseline activity levels of inpatients suitable for a hospital at home service, however primary objective research is needed in this treatment setting. this review also identified that functional change is infrequently measured along with physical activity, representing a missed opportunity to assess the impact of immobility in hospital on function. where they are reported, functional measures are highly diverse and data collection protocols vary, impeding comparisons between studies. a consensus-driven core outcome set for the investigation of functional decline in hospitalised patients would greatly facilitate the comparison and synthesis of research in this field. sedentary behaviour, defined as 'any waking behaviour characterized by an energy expenditure ≤ 1.5 metabolic equivalents (mets), while in a sitting, reclining or lying posture' [45] , was included in the search strategy as a related field to physical activity. no studies reporting sedentary behaviour as the primary outcome met the inclusion criteria, therefore, this concept is not discussed further in this review. funding the writing of this review was funded through a joint nhs lanarkshire-glasgow caledonian university phd studentship. the funders have had no input in the writing of this review or it's conclusions. hospital at home, guiding principles for service development world hospital at home congress. societies and programs why we should expand hospital-at-home during the covid-19 pandemic citation report for "hospital at home". clarivate analytics admission avoidance hospital at home. cochrane database syst rev no one size fits all-the development of a theory-driven intervention to increase in-hospital mobility: the "walk-for" study the effectiveness of inpatient geriatric evaluation and management units: a systematic review and meta-analysis trajectories and predictors of functional decline of hospitalised older patients predictors on admission of functional decline among older patients hospitalised for acute care: a prospective observational study reducing, "iatrogenic disability" in the hospitalized frail elderly the hospital elder life program: a model of care to prevent cognitive and functional decline in older hospitalized patients rethinking hospital-associated deconditioning: proposed paradigm shift. phys therapy daytime physical activity and sleep in hospitalized older adults: association with demographic characteristics and disease severity accelerometery shows inpatients with acute medical or surgical conditions spend little time upright and are highly sedentary: systematic review daily and hourly frequency of the sit to stand movement in older adults: a comparison of day hospital, rehabilitation ward and community living groups recommendations for older adults' physical activity and sedentary behaviour during hospitalisation for an acute medical illness: an international delphi study attitudes and expectations regarding exercise in the hospital of hospitalized older adults: a qualitative study preferred reporting items for systematic review and meta-analysis protocols (prisma-p) 2015: elaboration and explanation cochrane handbook for systematic reviews of interventions preferred reporting items for systematic reviews and meta-analyses: the prisma statement crd's guidance for undertaking reviews in health care targets for older adults' physical activity and sedentary behaviour during hospitalisation: an international delphi study development of a critical appraisal tool to assess the quality of crosssectional studies (axis) methodological quality (risk of bias) assessment tools for primary and secondary medical studies: what are they and which is better improved functional performance in geriatric patients during hospital stay measuring physical activity levels in hospitalized patients: a comparison between behavioural mapping and data from an accelerometer minimal intensity physical activity (standing and walking) of longer duration improves insulin action and plasma lipids more than shorter periods of moderate to vigorous exercise (cycling) in sedentary subjects when energy expenditure is comparable estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range assessing sedentary behavior with the geneactiv: introducing the sedentary sphere impact of oral treatment on physical function in older patients hospitalized for heart failure: a randomized clinical trial gosselink r (2006) physical activity and hospitalization for exacerbation of copd a pilot study examining activity monitor use in older adults with heart failure during and after hospitalization a pilot observational study to analyze (in)activity and reasons for sedentary behavior of cognitively impaired geriatric acute inpatients levels of evidence in medicine walking in hospital is associated with a shorter length of stay in older medical inpatients mobility activity and its value as a prognostic indicator of survival in hospitalized older patients very low levels of physical activity in older patients during hospitalization at an acute geriatric ward: a prospective cohort study 2020) how much do hospitalized adults move? a systematic review and meta-analysis association between 900 steps a day and functional decline in older hospitalized patients feasibility and inter-rater reliability of physical performance measures in acutely admitted older medical patients hospital-level care at home for acutely ill adults: a pilot randomized controlled trial hospital-level care at home for acutely ill adults: a randomized controlled trial sedentary behavior research network (sbrn): terminology consensus project process and outcome stepping toward discharge: level of ambulation in hospitalized patients acknowledgements thanks to dr alexandra mavroiedi of strathclyde university for advice given during the drafting of the protocol preceding this review and to julie smith, specialist librarian within the school of health and life sciences, glasgow caledonian university for assistance with devising the search strategy. thanks also to professor jon goodwin for advice on data analysis strategy and to dr phillipa dall for assisting with the full text review stage. js was funded to write this review through a joint nhs lanarkshire-glasgow caledonian university phd studentship.author contributions js, ua, ge and ds conceived the review. all authors contributed to the development of the search strategy and participated in the screening, review and selection of the included papers. js drafted the review and all authors reviewed, provided feedback and approved the final manuscript. the authors declare that they have no competing interests.ethical approval not applicable. open access this article is licensed under a creative commons attribution 4.0 international license, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the creative commons licence, and indicate if changes were made. the images or other third party material in this article are included in the article's creative commons licence, unless indicated otherwise in a credit line to the material. if material is not included in the article's creative commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. to view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. key: cord-346060-ns6v76rb authors: degli espinosa, francesca; metko, alma; raimondi, marta; impenna, michele; scognamiglio, elena title: a model of support for families of children with autism living in the covid-19 lockdown: lessons from italy date: 2020-06-02 journal: behav anal pract doi: 10.1007/s40617-020-00438-7 sha: doc_id: 346060 cord_uid: ns6v76rb italy has been the european country most affected by the covid-19 pandemic to date and has been in social lockdown for the longest period of time compared to other countries outside china. almost overnight, italian behavior analysts were faced with the challenge of setting up remotely whole-family systems aimed at maintaining adaptive skills and low levels of challenging behavior to be carried out solely by caregivers. given these extraordinary circumstances, the protocols available from the applied behavior-analytic, parent training, and autism literature did not appear to fully meet the needs of parents having to be with their children under extreme levels of stress in a confined space with limited reinforcers for 24 hr a day, 7 days a week. to meet this unprecedented challenge, we developed a dynamic and holistic protocol that extended to the full day and that recognized the need for sustainable intervention delivered solely by parents, who were often looking after more than one child. these practices are presented in this article, together with a discussion of lessons we have learned thus far, which may be useful for behavior analysts working in other regions in which the effects of the pandemic are not yet fully realized. although somewhat unorthodox, we include some parent comments at the end with the goal of sharing the parent perspective in real time as this pandemic unfolds across the world. before discussing responses to the pandemic, it may be helpful to say a few words about the italian health system as it concerns intervention for autism based on applied behavior analysis (aba). italy has a national health system in which autism is recognized as a condition that falls under the care of the state. education is free for all, and mainstream schooling is mandatory and therefore accessible by all children. there are no specialist schools. the delivery of therapeutic and educational services is regulated by registered professional bodies (i.e., psychologists, professional educators, speech and language therapists, neuro-rehabilitation technicians). aba-based intervention is not formally recognized by the italian health authorities, nor is it routinely offered as part of the state autism provision, which typically includes 1 hr per week of psychomotor therapy, 1 hr per week of logotherapy (i.e., speech and language therapy), and school attendance with varying levels of one-to-one educational support. the profession of behavior analysts is not officially regulated. despite the lack of formal governmental recognition of aba interventions for autism and a corresponding professional body, the country has witnessed a steady increase in the number of professionals credentialed by the behavior analyst certification board (bacb) in the past 10 years, verified course sequences, and state-funded health editor's note this manuscript is being published on a highly expedited basis, as part of a series of emergency publications designed to help practitioners of applied behavior analysis take immediate action to adjust to and mitigate the covid-19 crisis. this article was submitted on april 5, 2020, and received final acceptance on april 10, 2020. the journal would like to especially thank julie kornack and courtney tarbox for their expeditious reviews of the manuscript. it is important to note that this article reports the approach taken by a particular group of clinicians operating under completely unprecedented circumstances in one of the hardest hit regions of the world. there are many ways to use the science of applied behavior analysis to support families, and neither the authors nor the journal suggests this is the only approach or the best approach. however, this approach produced positive results for this group of families, and the editorial staff at the journal believes that the rest of the world of applied behavior analysis may benefit from learning from their experience. the views and strategies suggested by the articles in this series do not represent the positions of the association for behavior analysis international or springer nature. rehabilitation centers offering low-intensity (4 to 15 hr per week) aba intervention. as a result of parental demand for aba services, a considerable number of health professionals are enrolling in aba master's programs and consequently incorporating aba-based methods in their therapeutic practices for autism. schools have also begun to open their doors to bacb-credentialed professionals to support the individualized education plans of their students. nevertheless, ababased intervention remains largely privately funded by individual families and is, for the most part, carried out at home during the hours in which the child is not in school. at the time of this writing, the italian authorities have yet to provide statewide guidelines or funding for the continuation of intervention (aba and non-aba) via telehealth for children with autism during the lockdown period. in some regions (e.g., campania, lombardy, marche, emilia romagna), and with considerable variability, individual state-funded centers have begun to set up systems to provide intervention and parental support remotely. italy was one of the first european countries, together with germany, france, and spain, to register the first cases of covid-19 at the end of january 2020 and subsequently to impose movement restrictions on its citizens. for some weeks, it was the second country after china with the largest number of covid-19 cases. presently surpassed by the united states and spain, it currently registers the highest number of deaths related to covid-19 (world health organization, 2020) . on january 31, 2020, the italian government declared a state of national emergency and imposed the first social-distancing restrictions on february 24, with a decree closing all schools and many commercial activities in the northern regions (lombardy and veneto). these restrictions were gradually expanded and eventually extended to the rest of the country, with the period of complete national lockdown commencing on march 9 (ministry of health, 2020) . at the time of writing this paper, italy continues to be in complete lockdown, which includes home isolation, with outside movement restricted to one person per household and solely for the purpose of purchasing food or medicine. deliveries to households are limited to essential goods. outside physical activity is no longer permitted. however, if a child has a disability, she or he can be accompanied outside for brief walks, provided the parent carries a written certificate signed by a health professional attesting to the child's diagnosis and need to be outside. social-distancing measures during the initial lockdown period were less restrictive and were expected to last for a couple of weeks. although children had ceased going to school, and most home sessions had been interrupted, aba practitioners viewed this as a period similar to the summer holidays, where children spend long periods of time with grandparents and are essentially given free access to reinforcement, and parents are given a skeleton program of maintenance to prevent significant skill loss. under usual circumstances, we would expect to see some increase in challenging behavior and some skill loss during the summer months, but not so significant that it could not be addressed within the first few weeks of resuming the typical school and home intervention schedule. by the third week of the lockdown, it became clear that the isolation period would not only be extended to the rest of the country, but that measures would also become much more restrictive. thus, a different approach was required, especially because many parents (all family caregivers in the home are referred to as "parents" hereafter, for brevity) reported that their children were no longer satisfied with the usual reinforcers; were becoming increasingly uncooperative; were engaging in high levels of stereotypy and problem behavior, likely due to being denied access to regular but now unavailable reinforcers (e.g., swimming, going to the playground, taking extended car rides, going to the cinema or ice-cream parlor, participating in physical activity); were demanding high levels of undivided attention; and were becoming more difficult to direct to independent activities. parents also reported that they were struggling to reconcile the demands of distant working required by their employers with the needs of round-the-clock sole care of their children with autism, of siblings, and of their households in the absence of any outside help. although some families lived in the countryside and had access to a privately owned garden (i.e., private yard), many families lived in city apartments, where time spent outside was either prohibited or substantially limited due to the closure of parks and the shared courtyards. even those of us who are not psychologists saw clear early signs of mental health decline, as well as increasing marital conflict. although the latter problems were outside the scope of our practice as behavior analysts who are not also psychologists, referral to paid online psychotherapy or counseling, given the dire financial situation some families were experiencing, was not an option. nonetheless, we believed that the tools of the science of behavior could be extended to the larger family context to alter the repertoires of all its members and to increase contact with positive reinforcement for all. because restrictions in italy happened gradually, with families in the northern regions being in the first cohort, by the time families in the southern region were in lockdown, we had gathered sufficient data on the effects of the first 3 weeks of isolation with minimal structure and free reinforcement access. whereas for the northern families our work in the third week was focused on reducing the negative effects of 2 weeks of "free time," we were able to implement strategies proactively with the southern families to minimize the negative outcomes we observed for the families in the first lockdown cohort. prior to the lockdown period, none of our children displayed severe or unmanageable levels of challenging behavior, and they all had effective behavior management plans in place. after the first 2 weeks of lockdown with limited structure and free reinforcement access, in some of our first cohort families we observed the following during our online meetings: high levels of escape from simple instructions, the loss of independence and communication skills (appropriate mands), satiation (significant reduction in the time children spent with favorite items), an increase in problematic interactions between parents and all children, and unmanageable levels of mands for attention (both appropriate and inappropriate). parents reported being struggling to find new things to entertain their children with autism and siblings. sourcing novel toys or items to create new interests was not possible due to limited deliveries of nonessential items. in the following sections, we describe the protocol that was shaped through the frequent interactions with parents during our online observations and discussions. currently, as a group of professionals, we are serving approximately 30 families with this model. we were consulting with these families prior to lockdown and had been running home-based programs for at least 6 months. in the absence of published literature on interventions that require parents to engage with their children 24 hr per day, 7 days a week, in a confined space for a prolonged and undefined time period, we approached the problem inductively, altering what we did based on principles of learning, on what each individual situation required, and on what parents reported they felt they were able to do. the model developed was a systemic one, in which the client was no longer just the child in sessions working on educational targets but, rather, the whole family in its unique context. we began with an assessment of risk and an evaluation of each child's level of verbal functioning to establish the type of telehealth provision required (direct sessions or parent coaching; see ferguson, craig, & dounavi, 2019, for a review). the two main risks we aimed to mitigate were (a) parental burnout and (b) an increase in socially mediated challenging behavior of the child and siblings. we were less concerned with behavior maintained by automatic reinforcement, unless it was self-injurious. none of our children engaged in such behavior. the assessment was based on our history with the family, data from the child's prelockdown intervention, and direct contingency manipulation and observation via telehealth. for example, we asked the parent to leave his or her child with an activity while he or she talked to us, and we calculated how long the child was engaged without demanding parental attention. the main items included in the risk assessment (see table 1) were parents' prelockdown level of instructional control and social engagement with their children, the duration of the child's and siblings' ability to engage in solitary activities (either reinforcement or instructional, e.g., worksheets, chores, functional play), and parents' tolerance of nondangerous selfstimulation (e.g., flapping, noises, walking up and down, jumping on the sofa). in addition, we considered the child's age, the ability to engage in back-and-forth verbal interaction, the presence of siblings with a disability, and the number of supportive adults always present (i.e., single parent, both parents at home, other family members). for each individual family, we assessed the risk as high, medium, or low. the highest risk families were ones with a single parent or a parent with limited instructional control, who was on his or her own most of the day with two young children, one of whom had autism. in the case of one family, the parent was alone for most of the day with two adolescents with autism, one who was minimally verbal and the other who was verbally interactive. although this situation could have been considered high risk, in this specific case we considered it medium risk because the parent had excellent instructional control over both youngsters, who were both able to engage in solitary activities. as a general rule, the higher the risk, the higher the level of support we provided for the parent and the greater the daily structure. low-risk families included ones with both parents at home who were willing to engage with the child and sibling. in some cases, parents took turns to be with both children, so that one parent could be free. alternatively, each parent looked after one child, and they swapped children every few hours or every day. in these cases, it became crucial to ensure that both parents were involved in the care of the child and sibling, so that the burden of household management did not fall solely on the primary caregiver (parent 1). to achieve the involvement of both parents, provided they were both equally available, we worked separately with each one, setting up individual targets with each and developing a family schedule in which the time of each member was clearly specified. we identified three main learner profiles of the children, in terms of their need for support and perceived amenability to direct sessions over telehealth: 1. preschool-age children (n = 6): children who had not yet started elementary school (up to age 7); 2. minimally verbal children: children with limited adaptive, independent, and verbal skills (n = 16); and 3. verbally interactive children (n = 8). together with the risk assessment, this classification determined the daily family structure we arranged, as well as the type and frequency of support we provided as professionals. verbally interactive children were defined as being able to discriminate wh-questions (tact and intraverbal), follow multiple-step instructions, self-administer tokens, selfmanage interruption of reinforcement based on a timer, and not manifest challenging behavior in and out of sessions. verbally interactive children were those who we predicted would be able to sustain a direct session with their aba tutor (also commonly referred to as a technician or therapist) via telehealth. although none of the tutors had ever delivered interventions in this manner, extensive training was not needed because of their experience with the program targets and their familiarity with the child's home environment. for these families and tutors, contact with the aba consultant (commonly referred to as a supervisor) and/or lead tutor occurred once or twice per week to review targets, ensure that novel problem behavior was not emerging, and continue to provide support to the parents in managing the day. verbally interactive children received sessions in two formats. the first format involved the tutor remotely sharing the computer screen with the child, so what was once the table became the desktop computer. all visual stimuli were placed in individual electronic folders or powerpoint presentations, and the child responded to the materials presented via the tutor's desktop. tutors did not hold up cards to the screen, as it was too cumbersome, and some tutors also did not have the relevant materials at home. the second format was implemented with adolescents who were working on producing written responses; in that case, it was the child who remotely shared his or her screen with the tutor. the data collection system for these children remained unaltered from the prelockdown period, as the only change was the medium of delivery. most children received two 50-min sessions per day. for the two remaining profiles, preschool age and minimally verbal, we implemented a parent coaching system (see parsons, cordier, vaz, & lee, 2017 , for a review). the first telehealth session lasted up to 3 hr and was conducted by the team's aba consultant, with the participation of both parents and the team's lead tutor. subsequently, the consultant or lead tutor met with the family every day during the first and second week and every other day during the third intervention week and thereafter. the following protocol applies to families with preschool-age or minimally verbal children. the youngest child was 4 years old and had been receiving intervention for approximately six months. most of our families had been running an aba home-based program with the support of an aba consultant and tutor(s) for a minimum of 2 years and some for as long as 10 years. parents were not asked to take data, as this seemed unrealistic given how demanding their day was. professionals collected data during the online coaching sessions on the following: & parental report of challenging behavior; & parental report of their ability to maintain the agreed structure; & direct measurements of children's adherence to parental instructions; & direct measurements of challenging behavior during the coaching session; and & parents' procedural fidelity. prior to the lockdown period, children had access to a range of environments, each associated with its unique set of stimuli, signaling a specific reinforcement contingency. for example, children had learned that at school or during home sessions, brief periods of reinforcement were provided contingent on engaging in instructional activities and exchanging tokens. thus, children spent most of their learning time in school and in home sessions, where reinforcement access was regulated. for most of our children, the domestic context with parents signaled prolonged and often uninterrupted access to reinforcement in the evenings and on weekends. although not ideal, prior to the lockdown period, we did not view this as a significant problem because in most of their daily contexts (e.g., school and home sessions), children were able to engage in educational activities appropriately. during lockdown, however, the household became the only living context for all family members. this new set of circumstances created the need to institute an economic system that was sustainable, easy to implement for parents, and positively reinforcing for all members. the system also needed to promote the maintenance of adaptive skills and positive interactions, as well as allow for time off from interaction. during the first consultation session with each family, we worked with parents on structuring the entire day for all children (the child with autism and sibling), dividing it into blocks of activities to meet primary needs (breakfast, morning snack, morning outside time, lunch, afternoon nap for the younger children, afternoon snack, afternoon outside time, bath, and dinner). all times in between were considered dead times and, therefore, high-risk times that needed to be filled with contextually appropriate activities alternated with reinforcement intervals. one important aspect of structuring the day was to decrease the number of waking hours to reduce the fatigue and behavioral irritability that occurred toward the latter part of the day. we achieved two periods of roughly comparable duration between the mornings and afternoons by pushing lunchtime from 12:00 to 13:30-14:00 and bringing bedtime forward to no later than 21:00. as is fairly typical of southern european countries, our children often went to bed around 22:30 prior to the lockdown. we worked with parents to manipulate the stimuli associated with the end of the day (e.g., supper, bath, pajamas, story) to occur earlier than usual and in accordance with the recommendations for the optimal number of sleep hours for the child's chronological age (hirshkowitz et al., 2015) . table 2 shows an example of a daily schedule for a family in which parent 1 was alone most of the day with a 5year-old child with autism with limited independent and selfentertainment skills and a 3-year-old typically developing sibling. the day consisted of a rotation of contextually relevant activities or tasks for both the child and the sibling. we asked parents to identify one target per day in any of the activities, 1-week objectives, and 3-month objectives. we formulated the questions in this way: what would be helpful for you that your child learned? what do you want to teach your child today? what do you want to have taught your child in 1 week? when all this is over, what would you want your child to be able to do? in 1 month? in 3 months? parents chose from four types of activities broadly defined as follows: 1. independent activity: this encompassed any instructional activity the child could engage in without adult support (e.g., puzzles and shape sorters, worksheets, coloring, educational computer programs, domestic skills). visual activity schedules were utilized where useful (mcclannahan & krantz, 1999) . 2. household chores: these included chores the parent felt he or she could carry out with his or her child, giving the child things to do. we asked parents to go to each room and list all the chores that needed doing in each, however big or small. we asked parents to list every chore and not just the chores they thought their child could do or was already able to do. we wanted to identify objectives that were appropriate to the context and in which the parent was more likely to engage their child, as they needed to be done anyway. 3. tabletop discrete-trial teaching (dtt): we did not ask parents to run acquisition targets but only to maintain existing skills, with particular focus on clean responding without behavioral accessories (e.g., stereotypy). although it would be desirable if children maintained specific skill targets in specific programs, our purpose for having parents run dtt was primarily to help ensure that the children maintained some contact with the dtt contingency of rapid and accurate responding. 4. adult-led or shared activity (not dtt): these included activities that required the parent to engage one or both children, in which responses could be more loosely defined. examples of shared activities were completing simple crafts or making cookies. these were not necessarily reinforcing activities for the child with autism but often were reinforcing for the sibling. parents were coached to divide their attention between the two children, shape appropriate attention mands, and provide attention contingent on participation and engagement with the material. the targets for the child with autism were simply to remain in the activity and engage in some relevant responding. we did not include activities based on natural environment teaching (net), in which the parent actively had to manipulate the child's motivation and materials to evoke mands or to generalize language targets. this was because parents reported that they found this type of approach to be too effortful under these extreme circumstances. they reported they did not wish to be in a position to have to follow their child's motivation and to have to signal when that was no longer possible, risking the occurrence of challenging behavior. they also could not risk having to say no to something their child requested because of a lack of materials. although, in general, the daily structure centered on adult-led or shared activities alternated with periods of solitary reinforcement, all parents learned to interact with their children and siblings in a way that worked for them and maintained low rates of problem behavior. it is important to note that previous research exists that supports remote training of parents in net procedures (nefdt, koegel, singer, & gerber, 2010) , so we are not suggesting that this would not be a good approach for some families. two main reinforcement systems were implemented throughout children's waking hours: a token-based economy and an activity-based economy. in the token-based system, tokens were earned throughout the day and exchanged for preferred items. in the activity-based system, engagement in a less preferred activity (i.e., contextually appropriate activities) produced access to a more preferred activity. whether token based or activity based, the common element in both procedures was a system in which contingent relations between target behavior and preferred objects and activities were maintained, and reinforcers were unavailable outside those particular settings. we aimed to help parents establish a closed economy, meaning that engaging with parent-led reinforcement contingencies was the only way in which children could access those reinforcers, which is known to generate higher levels of responding (kodak, lerman, & call, 2007; reed, niileksela, & kaplan, 2013) . because we had already witnessed in our northern families (first cohort) the negative impact of free and prolonged access to reinforcers on (i.e., loss of children's skills and parental fatigue), we organized the household economic system so that reinforcement was accessible contingent on the production of contextually appropriate behavior for all children. this included the siblings, if they were under the age of 10 and not involved in remote schooling. the first step in closing the economy involved teaching parents to be able to limit access to all reinforcers for the child and siblings in every room of the household. parents classified reinforcers in terms of solitary and social for all children. solitary reinforcers were those that the child and sibling could consume on their own, and social reinforcers were those that required an adult and, where possible, were incorporated in the shared and adult-led activities. to help parents identify effective reinforcers, we accompanied them virtually through each room of the house and asked them to identify things their child liked or might like or items with which they had witnessed their child spend some time. every item was removed and placed in boxes, inside wardrobes or bags, or whatever container was available. in some cases, parents took pictures of the items to produce a reinforcer menu for the child (and sibling), whereas at other times, they took the child to the "shop," the place where all reinforcers had been stored. food treats were not available from the shop or the reinforcer menu; these were available at specific times during meals. the reasoning behind this was that food treats were items to be consumed rapidly, so the child was engaged for a very short period of time. our rationale in discontinuing noncontingent access to solitary toys and activities was that these items would hold their value and keep the children occupied longer. if the children were therefore able to be engaged with preferred solitary activities, the parent could safely have time off from the child and sibling. the secondary effect was to reduce escapemaintained problem behavior for both the child and the parent. by engaging with children in structured activities first, parents could access time to themselves and, as a result of contingent reinforcement delivery, also gain greater instructional control. we wished to create a mutually reinforcing situation for both the adults and the children, where parents could experience success in delivering instructions and interacting with their child, given that they would need to engage in this behavior daily in a confined space, over extended periods of time without a break. of course, discontinuing free access to reinforcers could also have the effect of increasing motivating operations that evoke problem behavior, so it was critical to support the children to be frequently successful in meeting the criteria for positive reinforcement, and thereby continuing to earn reinforcement on a frequent basis. many parents implemented the new reinforcement contingencies effectively, and the children learned very quickly that reinforcers were only available after the completion of activities or upon meeting the token schedule requirements. access to the reinforcer menu or shop was not available at any other time. children's mands for these items when they were not available were significantly reduced. because there were clear signals for reinforcement availability, children stopped asking for these items at other times, preventing parents from having to say no, thus reducing the risk of challenging behavior. children learned to mand for items (and receive them) only when the reinforcer menu was presented or when they were taken to the shop. they used whichever communication modality (e.g., vocal, sign, pointing, or selection-based modality) had been achieved prior to the lockdown period. given the level of stress the parents were experiencing after several weeks of lockdown, the likelihood was extremely high that they would reinforce problem behavior by providing the denied item to interrupt contact with the aversive stimulation produced by the child. we wished to reduce the risk by implementing the simplest possible system and not burdening parents with having to teach their child to tolerate denial. we simply removed that risk by giving frequent but contingent access to those items. the token system was implemented mainly for children who had limited verbal and nonverbal skills and who required frequent contact with reinforcement to engage in parent-led activities and instructions. a token system had been in place for all such children prior to the lockdown period, either at school or during home-based sessions. because we had always worked at home, all parents were familiar with the basic techniques; in fact, it was generally parents who manufactured the token boards, so the concept of a token economy system was not new to them. the fact that the system needed to be extended to the entire day was new and, in this sense, paralleled early applications of comprehensive token economy systems (ayllon & azrin, 1965 , 1968 phillips, 1968) . our token schedules consisted of three interrelated components: 1. the token-production schedule (the schedule by which responses earn tokens); 2. the exchange-production schedule (the schedule by which exchange periods are earned); and 3. the token-exchange schedule (the schedule by which the tokens were cashed in for preferred items or activities; see hackenberg, 2018 , for a review). the initial token-production schedule was set at fixed ratio (fr) 1, in which each target response (carrying out the parent's instruction within the activity proposed) produced a token to produce rapid acquisition. this was implemented throughout the day each time the parent gave an instruction. fairly quickly, parents naturally moved to a variable ratio schedule, in which a variable number of responses was required to produce a token, and they learned to adjust it based on the time of day or the difficulty of the task. the exchange-production schedule was fixed at fr 10, in which 10 tokens were needed to reach an exchange period. we did not make this variable, as it would have been too difficult for the parents to manage. the token-exchange schedule was fr 1-handing over the token boardwhereupon the parent presented the reinforcer menu or took the child to the shop to choose one item. during the exchange period, only one item or activity was allowed at a time. if the child wished to change the activity, then tokens had to be earned again for the change to occur. reinforcement duration varied according to parental needs and what was established by the daily schedule. in general, there were two types of reinforcement duration: brief (between 1 and 5 min) and long (up to 30 min). if parents needed their child to be occupied for additional time, they still had to interrupt after 30 min of consumption, place the item back in the shop, run a quick token board, and then open the shop or present the reinforcement menu again. the activity-based system was implemented when the parent had more than one child to look after, and it was extended to all siblings under the age of 10 if they were not involved in remote schooling. the system was based on creating half-hour blocks in which the parent was coached to engage the child and sibling in an adult-led or independent instructional activity for 30 min in order to produce 30 min of reinforcement time for everyone (the child, the sibling, and the parent). in the present article, we have described a model of supporting italian families during the past 6 weeks of lockdown. as professionals, we realized that this was one of the greatest challenges we would face in our careers. it soon became apparent, however, that the published literature and other tools upon which we typically rely were insufficient to deal with the magnitude and urgency of the present crisis. substantial previous research had been published on aspects of aba service delivery via telehealth, but little or no previous research had evaluated systems for transferring entire aba programs from in person to telehealth overnight, especially in the context of families living under total lockdown. in the absence of specific guidelines, we relied on an inductive process dictated by the tradition of our science, adapted published protocols, and derived procedures from principles. the system we were called to develop needed to be comprehensive and efficient. it needed to recognize the complexity of each individual family dynamic and be, at the same time, simple, realistic, and sustainable to maintain parental engagement. some may find the nearly complete elimination of noncontingent reinforcement and the application of a token economy across all waking hours to be somewhat extreme. however, the primary problem reported to us by parents before making this change was a lack of structure and loss of child motivation due to continuous free access to reinforcers. by programming reinforcement contingent on active engagement with the household schedule, we empowered the parents to increase their child's motivation and provide clear direction for everyone involved. if the parents had not been effective in providing sufficient antecedent support in the form of prompting and setting task difficulty at an achievable level, then such a system could have resulted in inadequate access to positive reinforcement. however, with support from their aba consultants, parents were successful in bringing order to their homes and helping their children to be calm, productive, engaged, and happy. despite the difficulties we are all experiencing, as both professionals and human beings, we have learned some valuable lessons that we hope will shape our ability to serve our families more effectively in the future. we have tremendous respect for the courage and dedication shown by the families we work with, who, at a time of adversity and uncertain future, have remained focused on the present. although parents realize that we are all learning as we go, we have seen a level of parental engagement that we had not been able to generate previously. such change, although borne out of crisis, may have enduring positive effects. our task moving forward will be to maintain these novel repertoires under more positive contingencies. we have not yet been able to analyze the data so far collected. we have included ongoing assessment of social validity by asking parents to comment on their experiences so far. we present three representative translated excerpts of parents' feedback: i thought it would be difficult to maintain the daily schedule of alternating instruction with reinforcement, but it has been very successful. i have stuck to it, and it has been all very natural and not too effortful. i am also very happy because i am able to spend time with my 2year-old, who is also making progress. i am able to play more with him and to focus on his speech. it's going well. (vittoria, parent of b, a 6-year-old girl with autism, and g, a 2-year-old boy) we received very simple and clear instructions-take away all reinforcers, engage him all day in simple domestic chores, give him routines, and give the reinforcers only after completing a token board. we saw an immediate change, zero problem behavior, and collaboration from c. if this situation had not happened, my husband and i would never have had such an enriched experience. seeing c so calm and compliant is the biggest reinforcer. (giada and davide, parents of c, a 9-year-old boy with autism) the management of g became very difficult. all his routines and perception of time had been disrupted. g, who was never interested in playing, became satiated with technology and was constantly searching for food, becoming very anxious during mealtimes. creating a closed reinforcer economy and dividing the day in clear sequential moments as to not get to the point of acute problem behavior and prevent boredom were essential. as parents, even in the absence of tutors, we are able to manage our child calmly and maintain learned skills. (veronica and giorgio, parents of g, a 7-year-old boy with autism) conflict of interest the authors declare that they have no conflicts of interest. ethical approval this article does not contain research conducted with human subjects. the measurement and reinforcement of behavior of psychotics the token economy: a motivational system for therapy and rehabilitation telehealth as a model for providing behaviour analytic interventions to individuals with autism spectrum disorder: a systematic review token reinforcement: translational research and application national sleep foundation's updated sleep duration recommendations: final report evaluating the influence of postsession reinforcement on choice of reinforcers activity schedules for children with autism: teaching independent behavior coronavirus, le misure adottate dal governo, provvedimenti attualmente vigenti, approvati dal governo in seguito all'emergenza sanitaria internazionale the use of a selfdirected learning program to provide introductory training in pivotal response treatment to parents of children with autism parent-mediated intervention training delivered remotely for children with autism spectrum disorder living outside of urban areas: systematic review achievement place: token reinforcement procedures in a home-style rehabilitation setting for "pre-delinquent" boys behavioral economics coronavirus disease (covid-19) pandemic publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations key: cord-345695-5vi9wibk authors: hicks, lorin l.; schwab, nathan a.; homyack, jessica a.; jones, jay e.; maxell, bryce a.; burkholder, braden o. title: a statistical approach to white-nose syndrome surveillance monitoring using acoustic data date: 2020-10-22 journal: plos one doi: 10.1371/journal.pone.0241052 sha: doc_id: 345695 cord_uid: 5vi9wibk traditional pathogen surveillance methods for white-nose syndrome (wns), the most serious threat to hibernating north american bats, focus on fungal presence where large congregations of hibernating bats occur. however, in the western usa, wns-susceptible bat species rarely assemble in large numbers and known winter roosts are uncommon features. wns increases arousal frequency and activity of infected bats during hibernation. our objective was to explore the effectiveness of acoustic monitoring as a surveillance tool for wns. we propose a non-invasive approach to model pre-wns baseline activity rates for comparison with future acoustic data after wns is suspected to occur. we investigated relationships among bat activity, ambient temperatures, and season prior to presence of wns across forested sites of montana, usa where wns was not known to occur. we used acoustic monitors to collect bat activity and ambient temperature data year-round on 41 sites, 2011–2019. we detected a diverse bat community across managed (n = 4) and unmanaged (n = 37) forest sites and recorded over 5.37 million passes from bats, including 13 identified species. bats were active year-round, but positive associations between average of the nightly temperatures by month and bat activity were strongest in spring and fall. from these data, we developed site-specific prediction models for bat activity to account for seasonal and annual temperature variation prior to known occurrence of wns. these prediction models can be used to monitor changes in bat activity that may signal potential presence of wns, such as greater than expected activity in winter, or less than expected activity during summer. we propose this model-based method for future monitoring efforts that could be used to trigger targeted sampling of individual bats or hibernacula for wns, in areas where traditional disease surveillance approaches are logistically difficult to implement or because of human-wildlife transmission concerns from covid-19. introduction north american bat species face several contemporary conservation challenges throughout their range, including threats to habitat from loss and alteration of forested environments, and direct mortality from development of wind energy infrastructure [1, 2] . however, transmission of pseudogymnoascus destructans (pd), the pathogen that causes white-nose syndrome (wns), has emerged as the most serious threat to over a dozen species of north american bats that use caves and mines for hibernacula [3] . the pd fungus invades skin tissues (e.g., wing membrane) which disrupts homeostasis and causes dehydration that corresponds to an abnormally high frequency of arousals from torpor [4] . bats with wns increase arousal [5] and acoustic activity rates [6] above baseline levels during the normal hibernation period, which depletes critical energy reserves and can ultimately cause mortality. wns has caused precipitous declines in populations of hibernating bats and has contributed to the federal listing of the northern longeared bat (myotis septentrionalis) as threatened under the u.s. endangered species act [7] and endangered listings for three bat species in canada under the species at risk act [northern long-eared bat, little brown bat (myotis lucifugus), and tri-colored bat (perimyotis subflavus)] [8] . monitoring for wns is a critical management action and primarily has focused on detecting the pd pathogen either directly from bats captured in hibernacula or with environmental samples from occupied caves and mines [9] . since its emergence in eastern north america in 2006, wns has spread westward with some models predicting wns to arrive to montana by 2026 [10] . in june 2020, sampling conducted at bridges in 3 eastern montana counties confirmed the presence of pd, but not wns [11] . further, wns was detected in a little brown bat in washington state in 2016 and pd detection continues to increase among sites and across different species within washington [12] . thus, there is a second wns epicenter, which could affect known and previously unrecognized susceptible bat species and increase the spread of wns through western north america from both the west and the east [13] . the presence of wns in the pacific northwest opens another front in critical efforts to combat bat declines and shortens the timeline for implementing conservation strategies to protect vulnerable bat species. this effort is complicated by the fact that winter hibernation behavior for most western species is poorly understood [14] , yet this is when wns has the greatest negative impacts on bat populations [2, 15, 16] . further, little is known about winter roost sites and activity patterns of many bats in western north america. a recent review indicates that wns-susceptible species rarely congregate in large numbers in the western u.s. and that known winter roosts may be relatively uncommon or difficult to identify [17] . thus, typical surveillance approaches of estimating hibernating bat numbers and sampling for pd implemented in eastern north america where large hibernacula are more common does not translate well to all ecoregions [18] . therefore, alternate approaches to facilitate pathogen surveillance, monitor disease impacts, and conduct mitigation efforts for wns are urgently needed [13] . in addition to wns, bats can be influenced by habitat alteration from anthropogenic activities, such as forest harvesting [19] . forested areas provide essential habitat features that support bat diversity, including roost sites (e.g., trees) and foraging areas (e.g., riparian zones, wetlands) [20] [21] [22] . sustainable management of these forest resources may minimize the environmental stress on bats outside of the winter season (when wns most severely impacts bats). despite a robust network of public lands managed for preservation in western north america [23] , bat species richness is low in some protected areas, such as glacier national park [24] and lower bat activity is commonly reported in undisturbed habitats compared to disturbed [19] . managed forests support many species of bats not found or poorly represented in gov/reqapp/usermain.asp. these data were produced as part of a regional bat acoustic monitoring network and we had no special privileges to access these data and obtained them via request from the montana natural heritage program. funding: funding was provided by national council for air and stream improvement, inc., plum creek timber, weyerhaeuser, stimson lumber, f. h. stoltze land and timber. weyerhaeuser provided access and logistical support to collect empirical data and provided support in the form of salary for authors lorin hicks and jessica homyack. weyerhaeuser also contracted with tetratech for data collection and analysis, completed by author nathan schwab. the funder provided support in the form of salaries for authors [lh, jh], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. plum creek timber, stimson lumber, f. h. stoltze land and timber also provided funding and support in the form of salary for lorin hicks. weyerhaeuser also contracted with tetratech for data collection and analysis and nathan schwab received support in the form of salary. the specific roles of these authors are articulated in the 'author contributions' section. the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. weyerhaeuser provided access and logistical support to collect empirical data and provided support in the form of salary for lorin hicks and jessica homyack. plum creek timber, stimson lumber, f. h. stoltze land and timber also provided funding and support in the form of salary for lorin hicks. weyerhaeuser also contracted with tetratech for data collection and analysis and nathan schwab received support in the form of salary. this does not alter our adherence to plos one policies on sharing data and materials. protected areas on public lands [1] and some forest management practices that reduce understory vegetation such as commercial thinning and prescribed burning can increase bat activity and occupancy [19, 25, 26] . nationally, public and private forestlands are managed under state forest practices rules, water quality best management practices, and forest sustainability programs (i.e., sustainable forestry initiative, forest stewardship council, american tree farm) to protect water quality and quantity, which includes riparian buffers that often provide habitat for bats. we quantified presence of bats across forested sites in montana, usa to document baseline levels of species diversity and activity rates prior to presence of wns. our objective was to evaluate long-term acoustic monitoring as a surveillance approach to monitor for potential wns presence in overwintering bat populations on both managed and unmanaged forest. specifically, we developed a statistical method to evaluate whether activity data occur outside the range of normal conditions, thus warranting more intensive sampling for the presence of pd on bats or in the environment. we predicted that bat populations in the western u.s. would have low levels of activity during winter months, high levels of activity during the summer, and that acoustic monitoring could be used as an effective approach for disease surveillance in remote areas of the intermountain west. our study area included forested areas across montana, usa (fig 1) . the forested areas in the western portion of the state were douglas fir (pseudotsuga menziesii)/snowberry (symphoricarpos albus) forest type, which generally characterized the region [27] and included locations of our acoustic detector stations. these forests had a mixed overstory, including douglas-fir, ponderosa pine (pinus ponderosa), grand fir (abies grandis), western larch (larix occidentalis), lodgepole pine (pinus contorta), and engelmann spruce (picea engelmannii), with understory vegetation comprised of snowberry, huckleberry (vaccinium spp.) and beargrass (xerophylum tenax). westside elevations ranged from 800 to 1150 meters. the climate in these ecoregions was continental-maritime with relatively low annual precipitation, with most precipitation occurring as snow [28] . the forested locations in eastern montana were characterized by limber pine (pinus flexilus) and ponderosa pine (pinus ponderosa) forest with understory of idaho fescue (festuca idahoensis) and bluebunch wheatgrass (agropyron spicatum). eastside sample site elevations ranged from 850-1520 meters. climate in the eastern ecoregions was continental with dramatic fluctuations in winter temperatures and longer, hotter, more arid summers than western ecoregions [29] . we selected 41 sampling sites that were near lentic or lotic systems and had �25% forest cover within a 1-kilometer buffer, estimated from the montana land cover data set in a geographic information system [30] (fig 1) . we did not randomly select sites for acoustic detectors but installed them in areas with potential for high bat activity that included proximity to standing live and dead trees, talus and rock cliffs, and waterbodies. we located four sites on intensively managed forest owned and managed by plum creek timber company (after 2016, weyerhaeuser) for production of sawtimber and other forest products. the remaining 37 sampling sites were selected from a regional bat acoustic monitoring network organized by the montana natural heritage program [31, 32] . these locations are primarily represented by federal and state landownership, but also include some tribal and private land. we we installed a single, full-spectrum acoustic recording unit (aru) at each sampling site. not all arus recorded data simultaneously or across the entire 2011-2019 study period, but we installed units for year-round recording of bat echolocation. each aru station consisted of a sm3bat or sm2bat+ acoustic detector (wildlife acoustics, maynard, massachusetts) and a microphone (u1 or smx-us) mounted on a pole at a height of approximately 3 meters. the arus operated on a 6-or 12-volt charging system (20-watt solar panel, 36-amp hour battery, and a charge controller) and housed in a weather-proof container on the ground below the microphone. we set the arus to record from sunset to sunrise to maximize battery life and balance with other logistical restraints of year-round sampling in remote locations. the units employed a sampling rate (samples per second) of 196,000, 256,000 or 384,000 khz. all arus used a minimum frequency filter of 8 khz, a trigger window of 2 seconds and a maximum file length of 5-8 seconds. most arus recorded in the wac0 compression format while four arus recorded directly to.wav format. the individual aru equipment and settings varied between the hardware platforms (sm3bat vs. sm2bat+), with detection distances of approximately 20-30 meters [33] , depending on the frequency of the source and other environmental variables (i.e., temperature and humidity) [34] . the equipment and settings were consistent for a given site throughout the study. the sensitivities of all microphones were within the manufacturer's specifications at the beginning of the deployment at each sampling site and replaced approximately annually. we examined equipment for functionality, checked microphone sensitivity, and exchanged data storage cards approximately once per month during summer and up to 6 months between visits during winter due to logistical constraints of access. each aru recorded a site-specific temperature approximately once every 1 or 5 minutes. at the end of our study, we parameterized acoustic files with sonobat 4.1.0 (sonobat, arcata, california usa) using a high-performance computing cluster at montana technological university. the parameters were then input into the sonobat montana [20160912] classifier to automatically assign a species classification to each bat pass. the montana classifier uses two regional species suites, each tuned to the species potentially present in that portion of the state. in cases where a bat pass was unable to be classified to species, a generic "bat" label was assigned. similar to the north american bat monitoring program [35] , we defined a bat pass as a sequence of echolocation pulses separated by more than 2 seconds of silence. we limited the maximum file duration to 5-8 seconds to reduce potential for recording more than one bat per sequence [36] . to quantify activity rates of bats, we analyzed the number of bat passes per detector-night (the number of operational detectors multiplied by the number of nights). for a night to be included in our estimates of detector-nights, the detector needed to register an internal temperature in the status file. we excluded data that did not meet this criterion from analysis. we manually verified a subset of diagnostic bat passes (approximately monthly for each species) with sonobat to ensure that species diversity of bats was accurate at all sampling stations [37] . we calculated the average number of passes per night over each month, by species, site and year using the ratio of total monthly qualified passes and the number of nights in the month. similarly, we calculated the average number of passes per night across all species, including passes without a species classification (total bat activity). a mean monthly temperature (˚c) was estimated from the mean of temperatures recorded at each site between sunset and sunrise across all nights in a month. we used a statistical model to describe variation in monthly-average nightly bat activity associated with several sources. to address our research questions, we aimed to characterize the extent to which activity varied among sampling sites, across years, by season, and in association with temperature. we fit a linear mixed-effects model with fixed effects for monthlyaverage mean temperature, season, and their interaction. we included random intercepts by site and year and random slopes for the temperature effect by site and year. thus, this model allowed for different overall levels of bat activity by site and year, and different temperature trends by site and year, while estimating population-average effects and quantifying the variation among sites and years. bat activity was log-transformed prior to analysis, and a constant of 0.01 was added prior to transformation to accommodate values of zero. we defined season by assigning each month to one of four calendar-based seasons (winter = dec, jan, feb; spring = mar, apr, may; summer = jun, jul, aug; fall = sep, oct, nov). we fit all models in r [38] using package lme4 [39] . we excluded sites with < ten months with at least one bat detection across all species from data used to fit the model. additionally, only data from 2012-2016 were used to fit the model, as limited data were available outside of this range. we note that both data restriction choices were performed to ensure sufficient data were available to estimate site-specific effects in the mixed effects model, but that no such restrictions were used in our raw data summaries. in addition to using the fitted model to describe variation in bat activity, we also used the model to generate prediction intervals [40] for new or future observations of bat activity in our region. we generated prediction intervals based on the model output using the 'predictinterval' function in package mertools [41] . we collected acoustic data used for our analysis between 28 sept 2011 and 4 august 2019, totaling 24,850 detector-nights at 41 sites. stations operated for an average of 606 (sd = 307) nights through the study. there were gaps in recordings because of equipment malfunction and wildlife encounters, but more than 5.37 million bat passes were recorded. after removing months with erroneous data due to equipment malfunction, 868 months of bat pass and temperature data were analyzed (per site mean: 21.2 months, sd = 10.7 months). we manually vetted acoustic files to confirm 13 species across the study, 11 of which were observed on managed forest sites (table 1) . three species [big brown bat (eptesicus fuscus), silver-haired bat (lasionycteris noctivagans), and western small-footed myotis (myotis ciliolabrum)] had confirmed activity in all calendar months, indicating that some bat species maintained some level of flight activity year-round. three presumed migratory species-spotted bat (euderma [2] . due to the high percentage of missing species information, our analyses include both estimates of total bat activity, i.e., total activity over all species, including bat passes not identified to species, and estimates for individual species where possible. across 24,850 detector-nights of sampling ambient temperatures, mean monthly temperatures ranged from -16.5˚c to 23.3˚c. mean monthly temperatures (± sd˚c) in montana varied across seasons [winter -1.7˚c (± 3.9˚c); spring 5.8˚c (± 4.3˚c); summer 16.2˚c (± 3.2˚c); and fall 6.7˚c (± 5.7˚c]). bat activity tended to be highest during summer months with most sites averaging >100 passes/night during july and august (fig 2) . additionally, most sites showed some activity during december and january, with one site averaging >10 passes/night. species-specific results show similar trends. we observed a strong positive association between average total bat activity and mean monthly temperature (fig 3) . the relationship was approximately loglinear for all 41 study sites, although the level of activity varied by site. results from our fitted model indicated a strong positive association between mean monthly temperature and total bat activity that varied by season (figs 4 and 5) . the estimated trends during the fall and spring indicated approximately 12.0-and 8.5-times greater numbers of bat passes per day, respectively, for every 5˚c increase in mean monthly temperature, on average, after adjusting for site and inter-annual differences. the association between bat activity and temperature was less pronounced during the winter and summer, where in both seasons we estimated approximately 2.8-fold greater activity, respectively, for 5˚c increases in temperature. overall levels of activity at a similar temperature also varied by season, although the difference was strongly dependent on temperature (fig 6) . we used the model random effects to estimate among-site and among-year variation in the mean response and temperature trends. we estimated considerable among-site variation in total bat activity after adjusting for temperature and seasonal effects, with site-specific means varying approximately 3.3-fold (1 sd) and among-year variation within a site of approximately 1.8-fold (fig 4) . estimated temperature trends among sites and among years were generally consistent, with variation in slopes of approximately 12% and 1% respectively. we fit this same model form to three individual species-eptesicus fuscus, myotis lucifugus, and m. californicus-to explore the possibility of seasonal differences in temperature associations among a species less vulnerable to wns [e. fuscus; [43] ], one highly vulnerable (m. lucifugus; [44] and one of unknown vulnerability (m. californicus). we note that since the majority of the bat passes were unidentified, the species-specific estimates may contain substantial unknown biases, as an unknown proportion of the unidentified bat passes consist of these species. our results suggest that winter activity for m. californicus is less strongly associated with mean monthly temperature than e. fuscus, while the reverse is suggested for the fall (fig 5) . we used the model fit to e. fuscus activity data (i.e., detections classified to the species e. fuscus) to illustrate a proposed monitoring approach with a statistical model for a single wnssusceptible species. the model was fit to data from all 41 sites to estimate among-site and among-year variation in activity, but we use the results to generate prediction intervals for four forest sites to depict how a landowner might implement this approach for wns surveillance monitoring. most observed activity data points fell within the 95% prediction interval, as expected (fig 7) . the prediction intervals were constructed to incorporate the estimated among-year variation in activity within a site. future observations of activity for these sites, along with model predictions, could be plotted to compare with prediction intervals. rapidly evolving technologies to passively observe and monitor wildlife concurrent with computational improvements in processing and analyzing large quantities of data are shifting management and research techniques from an animal-in-hand approach to indirect measurements of presence, abundance, diversity, and health [45, 46] . although acoustic monitoring has been implemented to investigate habitat relationships and community composition of bats [36] , uses of this technology are expanding into other objectives. here, we describe how yearround activity rates of bat species derived from acoustic monitoring can be used for surveillance monitoring for wns. we developed a simple and repeatable statistical modeling approach for wns surveillance monitoring with bat activity data collected from a broad geographic and temporal scale prior to known occurrence of wns in the intermountain west. this statistical approach can be applied elsewhere and may be particularly relevant for geographic locations where prominent hibernacula are inaccessible, rare, or unidentified [18] . further, our long-term and year-round collection of acoustic data for bats expands on limited knowledge of activity rates of species through time, seasons, across locations, and prior to wns. very little is known about the winter ecology of many species, specifically in western north america because of the limited sampling that has occurred during that season. technological advances in passive monitoring devices and identification software and an interest in wns has contributed to increased monitoring for bats in winter, when previously it was assumed they were rarely active [6, 47] . across our broad selection of 41 forested sites in montana, we documented a diverse community of bats (13 confirmed species), including at sites with a history of forest management. several species maintained some level of activity through winter, despite cold temperatures that averaged -1.0˚c in this season, which was below temperatures where at least some insect prey could sustain flight [48] . as expected, bat activity was positively related to warmer temperatures, although the strength of the relationship varied by season, with the strongest relationships with temperatures in spring and fall. in more temperate climates, other species of bats also displayed year-round activity that varied by season, sites, and species, including both migratory and non-migratory bats [2, 6] . the implications of winter activity of bats is not well-understood, particularly as it relates to body condition and energy stores or susceptibility to wns [6] . the ecology of bats infected with pd may lead individuals to change behaviors, such as higher activity rates during winter when bats typically use torpor to conserve energy [6] . aberrant behaviors by bats, including daytime activity out of roosts or hibernacula and during subfreezing temperatures increased after detection of wns in the southeastern u.s. [6] . however, the effects of winter bat activity on individual fitness have not been well-quantified. in north carolina, it was posited that year-round activity of typically migratory bats, including l. borealis, whose non-migratory behaviors could increase survival by reducing mortality from threats during migration, such as strikes from wind turbines [2] . alternatively, year-round activity by bats could be energetically costly if food resources do not meet metabolic demands and reduce reproductive output by individuals [2] . where underground caves or human structures are uncommon as hibernacula (e.g., the intermountain west), bats may congregate in smaller numbers in rock crevices during winter ( [49] ; unpublished data from this study). these wintering behaviors may provide protection against bat to bat transmission of pd. however, talus slopes can provide suitable temperature and humidity profiles for growth of pd, albeit below optimal levels [50] . the variability of relationships among prey availability, yearround activity, individual fitness, and susceptibility to wns remain a knowledge gap for north american bats [51, 52] . in addition to describing presence and seasonal activity rates of bats across forested sites in montana, we developed a process for using acoustic monitoring for disease surveillance that can be applied elsewhere. whereas approaches to incorporate uncertainty in estimates of population trends from bat count data in hibernacula are established, less information is available for managers to identify early-warnings from acoustic monitoring data [18] . here, we suggest the same basic framework that we used for the descriptive model of bat activity could be applied to an acoustic monitoring program aimed at identifying changes in bat activity consistent with wns. the approach could be used for single or multiple species and on individual sites or a collection of sites. additionally, the modeling approach is useful for detecting aberrant behaviors that could be associated with wns, including higher than normal activity rates during seasons where bats should be in torpor, or low activity rates due to population-level declines in bats. the general approach we consider is as follows: 1. collect baseline (pre-wns) data within a season or seasons of interest, and across several years and optionally across several sites. 2. fit a mixed-effects model to the data, incorporating variation with temperature, among years and among sites. optionally include other covariate information predictive of bat activity that can be easily gathered. 3. generate a population or site-level prediction interval that includes among-year variation. 4. monitor the collection of new data for excessive departures from the model prediction interval. in particular, look for bat activity in excess of the predicted range during winter months followed by bat activity below the predicted range during the following spring and summer [53] . we emphasize that our modeling approach was descriptive in nature and that we only recorded bat activity during nighttime. however, the approximately log-linear relationship with mean monthly temperature was strong in our dataset and may be useful in other investigations of bat activity. bat activity also showed approximately log-linear relationships with mean daily-max and daily-min temperatures. the non-random selection of sites included in our analysis limits the interpretation of the estimated model random effects or their application to other populations of sites. another limitation of species-specific results in this study relates to the large proportion of bat detections where no species label was assigned, where unknown biases could impact model estimates. we suggest that future site-specific surveillance models may be improved by including acoustic monitoring in daytime and by obtaining more high-quality species-specific call data with updated microphone technology [6] . we used prediction intervals to characterize expected ranges of among-year activity at the site level. one advantage of this approach in a monitoring program is that one set of intervals can be applied across multiple years without the need for annual refitting, provided suitable baseline data were used for model fitting. it is important to note that prediction intervals for mixed-effects models can be defined for any level of the random-effects structure [41] , with the appropriate level dependent on the end-use application. alternatives to prediction intervals could be employed in a monitoring program, including refitting a model each year to directly compare new data with a reference time period. currently, most conservation and management actions related to wns in north america are related to known hibernacula. for regions where large hibernacula are uncommon or rare, but where bats may still be susceptible to this threat, alternative approaches are necessary to ensure early detection of wns outbreaks and prevent further losses with targeted management actions. we propose a proactive and simple monitoring approach that could assist in managing risk of further loss of bat populations, which is especially relevant given current restrictions on field research due to concerns about transmission of covid-19 from humans to north american bats and among humans [54] . deploying passive arus to quantify bat activity, developing a predictive model of activity rates for one or more sites (including managed and unmanaged forest), and examining future data for deviations from these prediction intervals can all assist with a rapid response, including wns confirmation that could assist in recovery efforts. strong geographic and temporal patterns in conservation status of north american bats winter activity of coastal plain populations of bat species affected by white-nose syndrome and wind energy facilities white-nose syndrome: the devastating disease of hibernating bats in north america wing pathology of white-nose syndrome in bats suggests life-threatening disruption of physiology frequent arousal from hibernation linked to severity of infection and mortality in bats with white-nose syndrome winter behavior of bats and the progression of white-nose syndrome in the southeastern united states endangered and threatened wildlife and plants; 4(d) rule for the northern long-eared bat bats and white-nose syndrome 2020 determinants of pseudogymnoascus destructans within bat hibernacula: implications for surveillance and management of whitenose syndrome spread of white-nose syndrome on a network regulated by geography and climate fungus that causes white-nose syndrome found in eastern montana bat-killing disease white-nose syndrome confirmed east of the cascade range in washington first detection of bat white-nose syndrome in western north america. msphere activity following arousal in winter in north american vespertilionid bats western crevice and cavity roosting bats winter foraging of silver-haired and california myotis bats in western washington a review of bat hibernacula across the western united states: implications for white-nose syndrome surveillance and management improved analysis of long-term monitoring data demonstrates marked regional declines of bat populations in the eastern united states bently wigley t. site occupancy of foraging bats on landscapes of managed pine forest use of modified water sources by bats in a managed pine landscape bats in forests: what we know and what we need to learn bat activity in harvested and intact forest stands in the allegheny mountains us protected lands mismatch biodiversity priorities a macroecological perspective on strategic bat conservation in the u bat response to prescribed fire and overstory thinning in hardwood forest on the cumberland plateau effects of fire and its severity on occupancy of bats in mixed pineoak forests department of agriculture, forest service, intermountain forest and range experiment station ecoregions of the conterminous united states forest regions of montana land cover/land use theme montana natural heritage program montana bat and white-nose syndrome surveillance plan and protocols 2012 -2016 a directory of reports on long-term acoustic monitoring for bats at sites across the northern rocky mountains and great plains do you hear what i hear? implications of detector selection for acoustic monitoring of bats weather conditions determine attenuation and speed of sound: environmental limitations for monitoring and analyzing bat echolocation a plan for the north american bat monitoring program (nabat) on the importance of articulating assumptions when conducting acoustic studies of habitat use by bats montana bat and white-nose sydrome surveillance plan and protocols r: a language and environment for statistical computing. r foundation for statistical computing statistial intervals: a guide for practitioners mertools: tools for analyzing mixed effect regression models white-nose syndrome response team. bats affected by wns 2020 the resistance of a north american bat species (eptesicus fuscus) to white-nose syndrome (wns) an emerging disease causes regional population collapse of a common north american bat species computational sustainability: computing for a better world anda sustainable future how to learn to stop worrying and love edna monitoring winter acoustic activity of bats in montana effects of the environmental temperature on aedes aegypti and aedes albopictus mosquitoes: a review. insects winter bat activity in the canadian prairies unsuspected retreats: autumn transitional roosts and presumed winter hibernacula of little brown myotis in colorado frequent arousals from winter torpor in rafinesque's big-eared bat (corynorhinus rafinesquii) identifying research needs to inform white-nose syndrome management decisions. conservation science and practice going, going, gone: the impact of white-nose syndrome on the summer activity of the little brown bat (myotis lucifugus) fish & wildlife health committee and wildlife resource policy committee, bat working group, guidance for bat-related activities in response to covid-19. association of fish and wildlife agencies key: cord-342634-4ouhdjsr authors: semrad, katharina title: proteins with rna chaperone activity: a world of diverse proteins with a common task—impediment of rna misfolding date: 2010-12-26 journal: biochem res int doi: 10.1155/2011/532908 sha: doc_id: 342634 cord_uid: 4ouhdjsr proteins with rna chaperone activity are ubiquitous proteins that play important roles in cellular mechanisms. they prevent rna from misfolding by loosening misfolded structures without atp consumption. rna chaperone activity is studied in vitro and in vivo using oligonucleotideor ribozyme-based assays. due to their functional as well as structural diversity, a common chaperoning mechanism or universal motif has not yet been identified. a growing database of proteins with rna chaperone activity has been established based on evaluation of chaperone activity via the described assays. although the exact mechanism is not yet understood, it is more and more believed that disordered regions within proteins play an important role. this possible mechanism and which proteins were found to possess rna chaperone activity are discussed here. among all biological macromolecules, rnas represent one of the most functionally versatile players in the cell. rna molecules fulfill many different tasks such as coding and transfer of genetic information; they play regulatory functions in various cellular processes and catalyze chemical reactions (like cleavage and ligations). in addition to its functional versatility, rnas are also able to fold into countless different structures, many of which have similar stabilities as the native structure and therefore compete with the native fold. furthermore, rna molecules often undergo transition states during their folding pathways before they reach the native and active structure. these transient structures can represent traps along the folding pathway from which the molecules might have a hard time to escape and which then end up being long-lived intermediates. the reason for this structural versatility is the fact that rna consists of only four different bases which are easily capable of forming stable helices, that are not necessarily the native structure. the threshold for rna molecules to be able to perform their functions is usually the accomplishment of reaching its native and active structure. in the cellular environment, rna molecules do not appear as "naked" nucleic acids but always are found in conjunction with proteins. in some cases, the rna molecule helps the protein partner to fold correctly; in others, the protein stabilizes the rna structure. and last but not least proteins with rna chaperone activity aid during the folding process of rnas. proteins with rna chaperone activity open up misfolded rna structures and do not require atp [1] . furthermore, after the rna has been folded into its native structure, the protein becomes dispensable. although the term "rna chaperone" has been used routinely to describe various proteins that are capable to assist rna folding in vitro, the term rna chaperone is reserved to describe proteins whose rna folding activity has been verified on its natural target rna in vivo. therefore, most of the proteins in this paper will be referred to as proteins with rna chaperone activity if their rna folding activity was only determined in vitro and/ or on nonnatural rna targets. this paper will focus on the diversity of proteins with rna chaperone activity and which experimental assays are in use to determine whether a protein has rna chaperone activity. i will present examples for proteins with rna 2 biochemistry research international chaperone activity and discuss possible mechanisms of rna chaperoning. chaperone activity and rna misfolding 2.1. what are rna chaperones and proteins with rna chaperone activity? the list of proteins with possible rna chaperone activity is growing constantly. proteins with different activities that support rna folding are classified in this group. the definition of a protein with rna chaperone activity is that the protein prevents rna from misfolding by opening up misfolded structures. proteins with rna chaperone activity do not require atp, which distinguishes them from rna helicases, another group of proteins that facilitate rna folding (e.g., cyt-19) [2] . proteins with rna chaperone activity interact only transiently with rna molecules and are supposed to be dispensable once the rna has been folded correctly. this was shown for e. coli proteins s12 and stpa [3, 4] . a transient interaction and weak binding to rna might be difficult to define because many of the identified rna chaperones interact strongly with their target rnas and are found in rnp complexes like ribosomal proteins, hnrnps, la protein, and others. however, it has been demonstrated that a mutant stpa that shows stronger binding towards rna shows decreased rna chaperone activity suggesting that strong binding could also be detrimental to rna folding [5] . in that way, proteins with rna chaperone activity are also distinguished from "stabilizers" that are proteins that bind and stabilize an rna structure and are required to stay bound in order to keep the rna's native structure. cyt-18, the trna synthetase from neurospora crassa, is a "stabilizer" for the mitochondrial self-splicing group i intron: its presence is required to keep the native structure of the intron which otherwise unfolds readily. in the growing database of "proteins with rna chaperone activity", there exists an increasing number of proteins that simply possess rna annealing activity. a prominent and intensively studied member of this group is the bacterial host factor hfq that showed annealing activity on random substrates. hfq in addition is an rna chaperone as it was further demonstrated that hfq does possess unwinding activity upon its native substrates [6, 7] . in brief, the group of proteins with rna chaperone activity includes proteins that, first, open up misfolded structures without requirement of atp and that, second, are dispensable once the rna has been folded. 2.2. rna misfolding. rna molecules are prone to misfold in vitro and are usually prevented from misfolding in vivo. rna basically encounters two folding problems: a kinetic folding problem, where the rna molecule has to surmount kinetic barriers during the search for its native structure. secondly, rna molecules meet a thermodynamic folding problem as the final native structure often has to compete with alternative folds that have similar energetic stabilities [1] . rna folding is a hierarchical process, and first secondary structure elements have to form. secondary structural elements form between regions within the rna molecule that are in close proximity. they are a-form helices consisting of watson-crick base-pairs. secondary structures are very stable. the stability of a base-pair depends on the stability of both of its neighbouring base-pairs. already any rna of a reasonable length is able to form alternative base-pairs leading to alternative helices that become folding traps. tertiary structures are higher order structures that are built by assembling the secondary structure elements into a more complex collapsed fold. they can also involve formation of helices. this is the case in pseudoknots where either a loop region interacts with a distant single stranded region or with another distant loop. pseudoknots possess similar stability as secondary structures. but tertiary structural elements involve also other non-watson-crick interactions where for example, not only the watson-crick site of the nucleotide interacts with another nucleotide but also the hoogsteen edge or the sugar edge of the nucleotide is involved in hydrogen bonding [8] . an often reoccurring tertiary structure motif is the a-minor interaction where an adenine interacts with the minor groove of the a-form helix [9] . tertiary structures are often less stable and depend on the formation of secondary structures. finally, monovalent or divalent metal ions play an important role in tertiary structure formation. the first studies on rna structure and folding were done in the 1960s with yeast trna molecules. already then it was demonstrated that trnas are able to adopt two distinct conformations of which only one is the native structure which can be aminoacylated [10, 11] . the rna folding problem becomes even more prominent in the case of large rnas such as group i introns or in the context of large protein-ribonucleic acid complexes such as rnase p and the ribosome. it was demonstrated that the self-splicing group i intron of the thymidylate synthase gene of phage t4 misfolds in the absence of translation: when the ribosome does not prevent base-pairing between exon and intron sequences, the intron is not able to fold correctly and cannot perform the splicing reaction [12] . a similar observation was made with the group i intron of tetrahymena thermophila ribosomal rna: a subset of molecules misfolds and accumulates into an inactive population [13] . misfolding depends on exon sequences that form stable hairpins and intervene with 5splice-site formation. in vivo, however, some group i introns require the assistance of proteins to splice efficiently and prevent misfolding. for an example, the cyt-18 protein in neurospora crassa mitochondira is a trna synthetase which stabilizes the p4-p6 domain of group i introns and recruits cyt-19, an rna helicase, which then unwinds folding traps and promotes splicing [2, 14] . for large rnp complexes such as the ribosome, a growing body of evidence suggests that several additional factors such as helicases exist that assist during the folding process in vivo. as proteins with rna chaperone activity are very heterogeneous concerning their structure and their way to resolve the folding of rna molecules, there are various rna chaperone assays available to measure different activities. in principle, the assays can be divided into in vitro and in vivo assays that use either simple oligonucleotide annealing or displacement reactions or that measure catalytic activities of correctly folded ribozymes. measuring an activity that might be targeted more specifically to a certain subset of substrates in the natural environment of the putative rna chaperone makes it difficult to evaluate rna chaperone activity using a single assay. the substrates in the in vitro assay (e.g., oligonucleotides) might differ in sequence requirements or structure requirements from possible native substrates and might lead to negative results. strand unwinding assays might give positive results in the case of single-strand binding proteins. furthermore, in vivo assays to measure rna chaperone activity can be negatively influenced by possible toxicity of the putative rna chaperone when overexpressed or can lead to secondary effects in the cell that give false positive results. therefore, it is recommended to measure the rna chaperone activity at least in more than one chaperone assay to be certain that no non-specific activity is measured. figure 1) 3.1.1. oligonucleotide annealing. in this assay, two complementary oligonucleotides (oligos) present in concentrations above their dissociation constant are incubated together in the absence and in the presence of the protein to be evaluated for rna chaperone activity. an increase in the rate of duplex formation is observed when the tested protein has rna annealing activity. in principle two complementary short rna oligos are used in this assay, although it has been a habit to choose dna oligos instead. in order to measure rna chaperone activity, however, i think that rna oligonucleotides should be the preferred choice. detection methods of duplex formation include native gel electrophoresis where the two complementary rna strands can either be visualized by radioactive or fluorophor labelling and has been used in (besides many many other publications) [15] [16] [17] . rna annealing can alternatively be measured by observing the fluorescence resonance energy transfer (fret) upon the closing up of the two fluorescently labelled oligonucleotides (e.g., see [18, 19] ). activities. the ability of a protein to open up and unwind an already formed rna duplex is measured. to measure rna chaperone activity in contrast to helicase activity, this assay is performed in the absence of atp or an alternative energy source. analogous to the annealing assays, melting activity can be detected by using native gel electrophoresis or by measuring loss of fluorescence energy resonance transfer (fret) that occurs upon dissociation of the complementary fluorophor labelled rnas. in addition to under single turnover conditions, substrate to ribozyme annealing is measured. under multiple turnover conditions substrate dissociation is measured. (d) in the trans-splicing assay, the group i intron is split in two halves h1 (upstream exon, 5 -part of the intron) and h2 (3 -part of the intron and exon2), and splicing at low temperatures in the presence of chaperones is measured. (e) shows the cis-splicing assay where an enhancement of splicing at 37 • c is measured in the presence of chaperones. the construct (shosho) contains short exon 1 (27 nucleotides) and short exon 2 (2 nucleotides) sequences. the above-described detection methods, new approaches to detect folding or unfolding of single molecules emerge and include time-resolved nmr, which becomes a powerful tool to study folding of small rnas. cleavage. the hammerhead ribozyme cleavage reaction and folding of the ribozymesubstrate 3-way helical junction have been studied in a great detail. therefore, this assay represents a suitable tool to study rna chaperone activity upon folding of the hammerhead ribozyme-substrate construct. using the hammerhead cleavage assay, both annealing and strand displacement can be studied independently of each other [3, 20] . the advantage on the well-studied assay is that depending whether singleturnover conditions or multiple turnover conditions are employed, it is possible to distinguish between annealing and strand dissociation activities. using single-turnover conditions, where an excess of ribozyme and low concentrations of substrate are applied, substrate annealing is determined as substrate annealing becomes the rate limiting step. on the other hand, using multiple turnover conditions with an excess of substrate over ribozyme, the whole cleavage reaction is monitored consisting of annealing and product release. since product release represents the rate limiting step, product dissociation is measured. self-splicing of the thymidylate synthase group i intron (td intron) of bacteriophage t4 has been characterized, and the td intron has been used lengthily to monitor rna chaperone activity of various proteins. splicing of different group i intron constructs that do not fold readily into the splicing competent structure in vitro is tested with and without chaperones. cis-splicing assay. in this td intron construct both, 5 and 3 exons are shortened for the upstream exon down to 27 nucleotides and the downstream exon shortened to only 2 nucleotides. this short exon construct (td shosho) splices at 37 • c but rna chaperones increase folding and as a consequence the splicing rate of the short-exon construct is increased as well [5] . trans-splicing assay. here, the td intron is split into two halves in the center of loop l6 in the p4-p6 domain, where in the wild type group i intron an open reading frame for an endonuclease is present. the upstream in vitro transcribed construct contains 549 nucleotides of exon1 and 131 nucleotides of the 5 -part of the intron. the downstream construct consists of the remaining 147 nucleotides of the intron and 23 nucleotides of exon2. correct and efficient folding of the trans-intron-constructs is significantly impaired at 37 • c but works fine at elevated temperatures (55 • c), which is monitored through splicing [21] . chaperones with strong annealing and unwinding activities such as ribosomal protein l1 or l19 from e. coli are capable to catalyze trans-splicing at 37 • c or even at lower temperatures, for example, hnrnpi increases splicing at 25 • c [22] . in vivo rna chaperone activity assays (see figure 2) 3.2.1. in vivo folding trap assay in e. coli. splicing of the group i intron within the thymidylate synthase gene of phage t4 occurs efficiently in vivo. though, when splicing and translation are uncoupled by introducing stop codons in the upstream exon, splicing is significantly reduced. this is due to alternative base-pairing of exonic and intronic sequences which prevent the formation of the intron's native fold [12] . the mutant td precursor construct tdsh1 consists of an exonic stop codon and has an additional intronic point mutation (c865u) which further destabilizes the native intron structure. the tdsh1 construct is significantly impaired in splicing in vivo. overexpression of rna chaperones in the presence of the tdsh1 mutant is used to evaluate if the rna chaperone is able to rescue the misfolded intron and restore splicing [23] . transcription read-through of the chloramphenicol acetyl transferase gene (cat) is inhibited due to the preceding transcription terminator stem. the stable hairpin secondary structure of the terminator inhibits the polymerase to transcribe the cat gene and as a consequence no chaloramphenicol resistance is achieved. the cells are chaloramphenicol (cm) sensitive. proteins with rna chaperone activity are able to melt the terminator stem and as a consequence read-through occurs and the cells become chloramphenicol resistant. the transcription antitermination assay was used for assaying cold shock proteins or if1 from e. coli [24] [25] [26] . proteins that possess rna chaperone activity are very divers and span from viral to bacterial and human proteins that are involved in many different cellular processes. the list of rna chaperones is permanently growing. recently, a database for proteins with rna chaperone activity was established where every lab is able to contribute their data for a newly identified chaperone http://www.projects .mfpl.ac.at/rnachaperones/index.html [27] . the following selection of proteins with rna chaperone activity is not complete but points out the most important groups or single proteins. the first viral rna chaperone activities were reported in the early 1990s and showed that nucleocapsid protein 7 (ncp7) of hiv increases hammerhead ribozyme cleavage significantly [20, 28] . only a few years later, another virus-encoded protein with rna chaperone activity has been identified, the hdv delta antigen, which was also monitored in the hammerhead ribozyme assay and furthermore shown to be dispensable after folding has occurred [29] . flaviviridae core proteins were also monitored and shown to possess rna chaperone activity in a hammerhead cleavage assay and/or rna strand annealing activities [30, 31] . interestingly, many of the viral proteins show exceptional high degree of disorder. in the case of the flaviviridae core proteins, it was also reported that heat denaturation still retained strand annealing activity suggesting that the disordered domains of the proteins are involved in chaperoning. nucleocapsid proteins from two members of the coronaviridae family have been investigated and hammerhead ribozyme cleavage was shown to be enhanced in their presence [32, 33] . and again both nucleocapsid proteins show a high degree of disorder in in silico predictions. a growing body of evidence suggests that there exist many more viral proteins that possess rna chaperone activity. the list here is not complete but proteins that were shown to have only dna annealing activities were left out in this list. the majority of these small viral proteins show strong propensity for disorder which suggests that disorder might be a mechanistic requirement for chaperoning. interestingly, studies on nc proteins demonstrated that these proteins not only possess rna chaperone activity in vitro but also are required for strand annealing and strand displacement activities on their target rnas in vivo [33] . recently, a specific template switching assay designed to study strand displacement in a retroviral-derived system demonstrated that nucleocapsid protein from coronavirus shows rna chaperone activity and most likely is an rna chaperone in vivo [34] . stpa. the e. coli transcriptional regulator stpa, a 15 kd basic protein, was isolated as a repressor of a splicingdeficient group i intron in thymidylate synthase of phage t4 [4] . stpa was furthermore shown to possess strong rna chaperone activity in vivo in the folding trap assay [35] . the protein was tested in vitro in a strand-annealing and strand-displacement assay and exhibited strong activities in both tests [36] . more detailed studies on stpa revealed that the protein binds transiently to rna with a preference for unstructured regions and that binding to rna is diminished in the presence of high ionic strength [5] . in an elaborate study applying in vivo dms modifications to the rna, in vivo folding of the group i intron was evaluated in the absence and presence of stpa [37] : schroeder and coworkers demonstrated that stpa opens up tertiary interactions of the td group i intron. while the loosening effect is advantageous in wild type or misfolded introns, overexpression of stpa in the presence of introns that were already destabilized in their 3d structure was detrimental. structure prediction of stpa suggested that this protein exhibits more than 70% disorder and it was suggested that this unfolded regions of stpa might play a role in chaperoning [38] . ribosomal proteins are required within every cellular organism to build up the bacterial 70s or the eukaryal 80s ribosome. many ribosomal proteins further regulate transcription or translation of their own operons. in addition, ribosomal proteins are also involved in various very different cellular processes and fulfill extraribosomal functions [39, 40] . ribosomal proteins are highly conserved among various species and many ribosomal proteins have unusual long unstructured extensions that wind their way through the ribosome [41] . the first observation that ribosomal proteins are capable of chaperoning rna folding came from the belfort lab: screening for cellular factors that increase trans-splicing of the thymidylate synthase group i intron revealed that many ribosomal proteins possess chaperoning activity, with ribosomal protein s12 from the small ribosomal subunit having the strongest activity [3] . furthermore, s12 significantly increased hammerhead ribozyme cleavage [3] . a systematic study on large ribosomal subunit proteins from e. coli showed that 1/3 of the tested proteins possesses strong rna chaperone activity in vitro in the trans-splicing assay [21] . in addition, ribosomal protein l1 orthologs from eukarya, bacteria, and mesophilic archaea also exhibited strong transsplicing and cis-splicing activities in vitro [42] . although it makes sense that the rna chaperone activity of ribosomal proteins could play a role during ribosome assembly, a definite proof for the requirement of this activity in vivo has not yet been provided. recently, it was demonstrated that e. coli ribosomal proteins l15, l16, l18, and l19, that showed rna chaperone activity in vitro, further possess protein chaperone activity comparable to other protein chaperones such as hsp90 [43] . it was suggested that intrinsically unstructured domains of ribosomal proteins could play a role in chaperoning. the exact mechanism, however, still remains elusive (see section 5). cold shock proteins (csps) are conserved throughout bacteria and plants. they are expressed during cold-shock, when misfolding of rnas becomes a major problem for the organism and function as transcriptional antiterminator at low temperature. many experiments that have been performed to describe chaperone activity of cold-shock proteins utilize dna helices (and only sometimes in addition rna duplexes) and refer to the activity as nucleic acid melting activity. however, it has to be mentioned that there are no elaborate studies on whether there is a difference between rna duplex and dna duplex melting and whether dna melting activity automatically is the same as rna melting. e. coli contains nine members of the csp family and cspa, the major cold-shock protein and cspe were identified to interact non-specifically with rna molecules and to possess nucleic acid melting activities [44] [45] [46] . cold-shock proteins in higher plants are highly conserved. glycine-rich and zn-finger containing proteins from arabidopsis thaliana have been monitored for their nucleic acid melting activity, and it was shown that grp7 (glycinerich protein) and csdp1 (cold shock domain protein) possess rna chaperone activity [47] . a recent study also demonstrated that out of six glycine-rich proteins in rice (oryza sativa), which are likely to be involved in adaptation to cold-shock, three of them exhibit rna-(and dna-) melting activities suggesting that grps in plants fulfill a chaperoning role during low temperatures [48] . in e. coli translation, initiation factor 1 (if1) is a small 71 amino-acid long peptide, which contains 5 rigid β-barrels and belongs to the ob (oligomer-binding)-fold proteins such as the cold shock proteins. n-and c-termini of if1 are highly flexible. it was demonstrated that e. coli if1 is capable of complementing for a cspb and cspc double knock-out in bacillus subtilis suggesting that if1 and csps have at least partially overlapping activities [49] . e. coli if1 exhibits rna chaperone activity in various assays including rna annealing of complementary oligonucleotides, transsplicing, in vivo folding trap assay, and transcription antitermination in vivo and in vitro [25, 50] . heteronuclear ribonucleoproteins encompass a group of about 20 polypeptides that are predominantly nuclear in localization and are involved in rna processing. the first observation that hnrnps possess rna chaperone activity came in the early 1990s when fractionated hela nuclear extract was tested for annealing activity of an mrna and its antisense partner. three proteins, hnrnp a1, c1 and u, were identified and hnrnp a1 was further shown to enhance hammerhead ribozyme cleavage in vitro [16, 20] . later, a detailed study on possible functions of ro rnps, which are ro ribonucleoprotein complexes, composed of a small noncoding cytoplasmic rna, termed y rna and its protein partners was conducted: besides the permanently associated proteins ro60 and la, subpopulations of ro-rnps also contain hnrnp i and hnrnp k, both of which exhibited strong rna chaperone activity in vitro in the transsplicing and the cis-splicing assay [22] . hnrnp i is identical to poly-pyrimidine binding protein (ptb) isoform 4 and was identified as a splicing suppressor in mammalian cells [51] . it regulates cap-independent translation, localization of cytoplasmic rnas, and poly-a-site cleavage [52] . ptb belongs to the ires transacting factors (itafs), which are host factors (like la, hnrnp k, nucleolin, unr and many others) that interact with viral rnas and induce conformational changes that then lead to translation initiation [53] . it was further reported that calcivirus replication requires ptb but only at lower or at higher temperatures than the permissive 37 • c, suggesting a chaperoning role of ptb [54] . members of the group of itafs have been implicated in rna chaperoning like unr, a cold-shock domain containing protein [55] , human la protein, and hnrnp k [22] . hnrnp k is also a multifunctional protein that is a transcriptional factor for c-myc and c-src [56] [57] [58] ; it enhances splicing [59] and is a translational regulator [60] . la proteins primarily bind rna polymerase iii transcripts and protect them from nuclease attack [61] . they also interact with pre-trnas at their uuu-3 oh ends and facilitate their maturation. la contributes to assembly of rnp complexes by retaining rnas in the nucleus. la is also involved in translation regulation. and human la was demonstrated to possess rna chaperone activity in vitro in the cis-splicing assay and in vivo in the folding trap assay [22] . hfq. the bacterial protein hfq was first discovered in the end 1960s as a host factor for bacteriophage qβ replication [62] . the bacterial protein is a pleiotropic regulator for gene expression in bacteria. it interacts with many small rnas and their mrna targets and regulates posttranscriptional regulation of small noncoding rnas such as dsra, sodb, oxys, rpra, and spot42 [63] [64] [65] [66] [67] . hfq preferentially binds to a/u rich, unstructured regions. hfq encompasses an sm-domain, which is highly conserved among various species and usually is found in eukaryotic spliceosomal rnps. crystallographic studies of escherichia coli, pseudomonas aeruginosa, and staphylococcus aureus hfq proteins showed that hfq forms homohexameric ring structures with a central cationic pore that forms the rna binding site [68] [69] [70] . using strand annealing and strand melting assays to measure rna chaperone activity of hfq, only strand annealing activity was observed [27] . however, a detailed study using rnase footprinting on hfq's interaction with its target rnas sodb mrna and the small noncoding regulator ryhb rna demonstrated that hfq indeed did loosen secondary structures within sodb mrna that lead to binding of its regulatory rna rhyb [7] . a similar observation was made using fluorescence labelled rpos mrna and dsra small noncoding rna [6] . by means of fret, it was shown that hfq induces annealing of dsra to rpos mrna and prior to the annealing event hfq disrupts rpos secondary structure elements. consequently, hfq is entitled to be called rna chaperone. the prion protein is a misfolded isoform of the essential component of prion diseases such as creutzfeldt-jakob disease in humans-one of several neurodegenerative diseases. the function of the human prion protein is not clearly understood. it was demonstrated that the prion protein has rna (and dna) annealing activity [71] ; however, it was not yet shown if it possesses also rna unwinding activity and may therefore be classified as an "annealer". interestingly, the prion protein contains an intrinsically unstructured n-terminal domain [72] . the fragile x mental retardation protein (fmrp) is linked to the fragile x syndrome as the disease is due to transcriptional silencing of the gene. fmrp possesses rna binding activity and its interaction partners include a large number of mrnas, micrornas, sirnas, and small noncoding rnas as well as a multitude of different proteins [73] [74] [75] [76] . it was demonstrated using hammerhead ribozyme cleavage that fmrp possesses rna chaperone activity [77] . and finally in line with many other proteins with rna chaperone activity, it is interesting to mention that fmrp consists of a highly disordered c-terminus suggesting that the substrate versatility of fmrp might be accomplished through its structural disorder [78] . chaperones provide a critical cellular activity. proteins with rna chaperone activity are very divers in structure as well as in function: stpa, a transcriptional activator and repressor of a multitude of bacterial genes, is a small (15 kd) bacterial protein with intrinsically unstructured regions. stpa has strong rna chaperone activity. on the other hand the bacterial protein hfq is a large multidomain protein complex (60 kd) and folds into a compact ring-like structure. among ribosomal proteins, many were shown to possess rna chaperone activity (e.g., one third of large ribosomal subunit proteins from escherichia coli show rna chaperone activity in vitro). ribosomal proteins are usually small proteins many of which have long unstructured domains and are highly basic proteins. proteins with rna chaperone activity do not require an external energy source as rna helicases do. this raises the question of how rna chaperones accomplish the rna folding task and where the energy for this process comes from. proteins with rna chaperone activity in most cases encompass two major activities: the annealing activity and the unwinding activity (see also figure 3 ). many proteins with rna chaperone activity are highly basic proteins and therefore interact readily with negatively charged rna molecules. in that way, they might stabilize folded states by bringing together distant regions of the rna molecule and as a consequence increase rna double-strand formation. this mechanism could be comparable to the action of chemical chaperones such as osmolytes which are small organic compounds, that do not interfere with the cellular metabolism but speed up folding processes enabled through a crowding effect [79] . another indication that a crowding effect might play a role at least to some extent during rna annealing is the following: when rna chaperone activity is measured in vitro, there is always an excess of protein over rna present in the assay. for example, in the trans-splicing assay, 200 nmols of rnas (leading to a 20 nm end-concentration) are tested for folding in the presence of 1-2 μm protein. it was shown that e. coli ribosomal protein l1 displays maximal rna chaperone activity starting from 400 nm up to 2 μm protein concentration [42] . this means that at least a 20-fold excess of protein to rna has to be present to achieve maximal chaperoning activity of ribosomal protein l1 from e. coli. in this line, it also has to be mentioned that in the in vivo chaperone assay, which uses the folding trap of a misfolded group i intron in the thymidylate synthase gene of phage t4, it is always necessary that the measured protein is overexpressed and available in higher concentrations [23] . for example, the e. coli protein stpa, which is found constitutively expressed in the bacterial cell, only shows its rna chaperone activity in vivo when stpa is additionally over-expressed from an expression vector, thus showing that the cellular concentration of stpa is not sufficient to increase folding of the misfolded group i intron. certainly, this observation might be due to the engagement of stpa in other regulatory functions in the bacterial cell; however, it also points to the direction that more than one molecule 8 biochemistry research international of stpa is required to assist folding of the td group i intron. as a consequence the question rises if and how it is possible to distinguish between rna chaperone activity and a nonspecific single-strand rna binding activity of the protein that might both prevent misfolding. using the in vivo folding trap assay, however, not only proteins with possible rna chaperone activity like stpa had been tested but also a viral single strand binding protein from influenza virus (np) was tested and did not show any increase in splicing suggesting that single strand rna binding might not be sufficient for chaperoning. furthermore, a detailed study on stpa wild type and mutants demonstrated that only the fulllength stpa was able to show rna chaperone activity by simultaneously interacting with two rna molecules [5] . rna chaperone activity of stpa has been studied for more than a decade. it was shown that stpa has strong in vivo and in vitro rna chaperone activities. in a mechanistical in vivo study of stpa, schroeder and coworkers demonstrated that stpa loosens tertiary contacts within the thymidylate synthase group i intron [37] . in contrast, the neurospora crassa trna synthetase cyt-18 that also increases group i intron splicing of td stabilizes tertiary interactions. but how is the opening of tertiary structure elements accomplished without the hydrolysis of atp? this strand unwinding activity is more difficult to explain as the question remains of how a protein can actively open up hydrogen bonds when no apparent source of energy is required. in the protein world, it became more and more visible that the classical structure-function paradigm does not necessarily hold for many proteins and their activities. a growing body of evidence suggests that a multitude of proteins do not fold into compact domains but are fully or at least partially unstructured [80] . in eukaryotes, for example, conservative estimations point out that 5%-15% of all proteins are completely disordered and 50% of the cellular proteins have at least long unstructured domains. an interesting study by tompa and csermely demonstrated that among chaperones a significantly high percentage of proteins show long unstructured regions [38] . among rna chaperones, the percentage of at least partially disordered proteins is even higher (54%) than in the group of protein chaperones (36.7%). disordered proteins and protein segments allow a broad versatility for interaction partners and in this case for interaction with different rna molecules. but it can also explain the ability of proteins with rna chaperone activity to multitask as so far no rna chaperone has been identified whose only task is to aid in rna folding. interestingly, it was recently demonstrated that some ribosomal proteins that possess rna chaperone activity and contain disordered regions are also capable to chaperone protein folding suggesting once again that disordered regions provide high versatility for substrate interactions [43] . the idea of disordered rna chaperones is especially attractive because there are many advantages of proteins with disordered regions over compact proteins: (1) the main advantage of a disordered region is that it can easily interact with a range of many different partners and is not limited to a single binding pocket or recognition element on a partner molecule. (2) the bigger surface of the unstructured protein might provide a "loosening effect" for the incorrectly folded rna molecule. (3) the troublesome question of where the energy for the rna unwinding might come from could be explained by the gain of compactness upon interaction with the rna and a simultaneous loosening of the rna structure (see figure 3 (b)). as a consequence, the rna gains another chance to fold correctly. (4) the intrinsically unstructured protein might provide a folding platform for the rna as the chaperone holds the rna molecule in close proximity. in future the research focus on rna chaperones will lie on the understanding of the molecular mechanism and how intrinsically unstructured regions in proteins might play a role in function. interestingly, two very closely related ribosomal proteins l1 from archaea, that encompass 70% aminoacid identity, possess opposite activities: the mesophilic l1 protein displays strong rna chaperone activity whereas the thermophilic one inhibits ribozyme assays [42] . a detailed mutation study will likely shed light on the different activities and explain the rna chaperoning mechanism at least for a subgroup of rna chaperones. the big challenge, however, will be to identify in vivo targets of rna chaperones. rna chaperones are evaluated in assays for their broad specificity but in vivo they might be specialized to supervise folding of only a subset of rna molecules. the specificity might possibly be conferred by a different domain than the chaperoning activity. rna chaperones and the rna folding problem a dead-box protein functions as an atp-dependent rna chaperone in group i intron splicing escherichia coli proteins, including ribosomal protein s12, facilitate in vitro splicing of phage t4 introns by acting as rna chaperones escherichia coli protein stpa stimulates self-splicing by promoting rna assembly in vitro rna chaperone activity and rna-binding properties of the e. coli protein stpa spectroscopic observation of rna chaperone activities of hfq in post-transcriptional regulation by a small non-coding rna hfq, a new chaperoning role: binding to messenger rna determines access for small rna regulator geometric nomenclature and classification of rna base pairs rna tertiary interactions in the large ribosomal subunit: the a-minor motif two interconvertible forms of tryptophanyl srna in e. coli native and renatured transfer ribonucleic acid a ribosomal function is necessary for efficient splicing of the t4 phage thymidylate synthase intron in vivo alternative secondary structures in the 5 exon affect both forward and reverse self-splicing of the tetrahymena intervening sequence rna a tyrosyl-trna synthetase recognizes a conserved trna-like structural motif in the group i intron catalytic core domain structure and rna annealing activity of the escherichia coli regulatory protein stpa rna annealing activities in hela nuclei hiv-1 nucleocapsid protein as a nucleic acid chaperone: spectroscopic study of its helix-destabilizing properties, structural binding specificity, and annealing activity coupling rna annealing and strand displacement: a fret-based microplate reader assay for rna chaperone activity dissecting rna chaperone activity an rna chaperone activity of non-specific rna binding proteins in hammerhead ribozyme catalysis rna chaperone activity of large ribosomal subunit proteins from escherichia coli rna chaperone activity of protein components of human ro rnps assaying rna chaperone activity in vivo in bacteria using a ribozyme folding trap escherichia coli cspa-family rna chaperones are transcription antiterminators transcription antitermination by translation initiation factor if1 assay of transcription antitermination by proteins of the cspa family rna chaperones, rna annealers and rna helicases protein enhancement of hammerhead ribozyme catalysis identification and characterization of the rna chaperone activity of hepatitis delta antigen peptides the hepatitis c virus core protein is a potent nucleic acid chaperone that directs dimerization of the viral (+) strand rna in vitro rna chaperoning and intrinsic disorder in the core proteins of flaviviridae role of rna chaperones in virus replication coronavirus nucleocapsid protein is an rna chaperone coronavirus nucleocapsid protein facilitates template switching and is required for efficient transcription assaying rna chaperone activity in vivo using a novel rna folding trap assays for the rna chaperone activity of proteins rna chaperone stpa loosens interactions of the tertiary structure in the td group i intron in vivo the role of structural disorder in the function of rna and protein chaperones how common are extraribosomal functions of ribosomal proteins? extraribosomal functions of ribosomal proteins atomic structures at last: the ribosome in 2000 biochemistry research international ribosomal proteins: phylogenetic conservation and splicing inhibition janus chaperones: assistance of both rna-and protein-folding by ribosomal proteins cspa, the major cold-shock protein of escherichia coli, is an rna chaperone cold shock induces a major ribosomal-associated protein that unwinds double-stranded rna in escherichia coli nucleic acid melting by escherichia coli cspe cold shock domain proteins and glycine-rich rna-binding proteins from arabidopsis thaliana can promote the cold adaptation process in escherichia coli glycine-rich rna-binding proteins are functionally conserved in arabidopsis thaliana and oryza sativa during cold adaptation process complementation of cold shock proteins by translation initiation factor if1 in vivo rna chaperone activity of translation initiation factor if1 regulation of alternative 3 splice site selection by constitutive splicing factors minireview: polypyrimidine tract binding protein antagonizes exon definition cellular internal ribosome entry segments: structures, trans-acting factors and regulation of gene expression feline calicivirus replication: requirement for polypyrimidine tract-binding protien is temperaturedependent the apaf-1 internal ribosome entry segment attains the correct structural conformation for function via interactions with ptb and unr heterogeneous nuclear ribonucleoprotein k is a transcription factor identification of the src pyrimidine-binding protein (spy) as hnrnp k: implications in the regulation of src1a transcription specific binding of heterogeneous ribonucleoprotein particle protein k to the human c-myc promoter, in vitro heterogeneous nuclear ribonucleoprotein (hnrnp) k is a component of an intronic splicing enhancer complex that activates the splicing of the alternative exon 6a from chicken βtropomyosin pre-mrna mrna silencing in erythroid differentiation: hnrnp k and hnrnp e1 regulate 15-lipoxygenase translation from the 3 end the la protein factor fraction required for the synthesis of bacteriophage qβ-rna a small rna regulates the expression of genes involved in iron metabolism in escherichia coli regulatory roles for small rnas in bacteria hfq: a bacterial sm-like protein that mediates rna-rna interaction hfq is necessary for regulation by the untranslated rna dsra the sm-like hfq protein increases oxys rna interaction with target mrnas structure of pseudomonas aeruginosa hfq protein sm-like proteins in eubacteria: the crystal structure of the hfq protein from escherichia coli structures of the pleiotropic translational regulator hfq and an hfq-rna complex: a bacterial sm-like protein the prion protein has rna binding and chaperoning properties characteristic of nucleocapsid protein ncp7 of hiv-1 scavenger, transducer, rna chaperone? what ligands of the prion protein teach us about its function microarray identification of fmrp-associated brain mrnas and altered mrna translational profiles in fragile x syndrome a drosophila fragile x protein interacts with components of rnai and ribosomal proteins rna and micrornas in fragile x mental retardation rna cargoes associating with fmrp reveal deficits in cellular functioning in fmr1 null mice the fragile x mental retardation protein has nucleic acid chaperone properties disordered rna chaperone proteins: from functions to disease protons, osmolytes, and fitness of internal milieu for protein function intrinsically unstructured proteins: re-assessing the protein structure-function paradigm both referees of the paper are thanked for their valuable comments. doris chen is thanked for critically reading and chaperoning the paper. k. semrad is supported by a hertha firnberg fellowship (t261) from the austrian science foundation (fwf). key: cord-299007-5m6lk409 authors: paterson, r. russell m. title: cordyceps – a traditional chinese medicine and another fungal therapeutic biofactory? date: 2008-05-31 journal: phytochemistry doi: 10.1016/j.phytochem.2008.01.027 sha: doc_id: 299007 cord_uid: 5m6lk409 abstract traditional chinese medicines (tcm) are growing in popularity. however, are they effective? cordyceps is not studied as systematically for bioactivity as another tcm, ganoderma. cordyceps is fascinating per se, especially because of the pathogenic lifestyle on lepidopteron insects. the combination of the fungus and dead insect has been used as a tcm for centuries. however, the natural fungus has been harvested to the extent that it is an endangered species. the effectiveness has been attributed to the chinese philosophical concept of yin and yang and can this be compatible with scientific philosophy? a vast literature exists, some of which is scientific, although others are popular myth, and even hype. cordyceps sinensis is the most explored species followed by cordyceps militaris. however, taxonomic concepts were confused until a recent revision, with undefined material being used that cannot be verified. holomorphism is relevant and contamination might account for some of the activity. the role of the insect has been ignored. some of the analytical methodologies are poor. data on the “old” compound cordycepin are still being published: ergosterol and related compounds are reported despite being universal to fungi. there is too much work on crude extracts rather than pure compounds with water and methanol solvents being over-represented in this respect (although methanol is an effective solvent). excessive speculation exists as to the curative properties. however, there are some excellent pharmacological data and relating to apoptosis. for example, some preparations are active against cancers or diabetes which should be fully investigated. polysaccharides and secondary metabolites are of particular interest. the use of genuine anamorphic forms in bioreactors is encouraged. too much about cordyceps is unsubstantiated. this literature is written to sell so-called medicines to potentially vulnerable people with serious diseases. on the other hand, there is convincing scientific information that indicates significant pharmacological properties which are worth assessing (see table 1 ). the present large review undertakes this task and deals with papers that use the name cordyceps sometimes in its most general sense, especially when the revision of sung et al. (2007) is considered. there follows an extended introduction to the topic. the title relates to another in this journal concerning the fungal traditional chinese medicine (ftcm), ganoderma (paterson, 2006) . in that case, the fungus was indeed a biofactory in the sense that numerous compounds have been reported from the fungus. what is the situation with another ftcm, cordyceps? the immediate answer is that the state of the art is considerably less developed (see table 2 for a list of secondary metabolites). there is a general impression that this fungus is being used in a modern context, before the benefits, and even what is being used, have been determined scientifically. cordyceps is one of a growing number of ftcm being considered as cures for modtable 1 medically related purported effects of various cordyceps taxa (or preparations) as described by various authors ern human diseases. many commercial products are available in the market (e.g. didanosine from cordyceps militaris). these nutraceuticals are considered to relieve the ''stress for humans of living in technologically developed societies" by stimulating basic and secondary responses of the immune system (lakhanpal and rana, 2005) . the fungus represents a genus of perithecial ascomycetes (phylum ascomycota) classified in the clavicipitaceae, a monophyletic group included in the order hypocreales. the genus contains over 400 species and the anamorphs of most are unknown. paecilomyces is considered traditionally to host the anamorphs but this has been disputed. sung et al. (2007) should be consulted for an up-to-date revision (and see later). cordyceps are parasites of insects or fungi, often exhibiting a high degree of host specificity (fig. 1) . however, the cordyceps species associated with lepidopteran hosts do not represent a monophyletic group. there is even a high degree of genetic variation within cordyceps sinensis which creates difficulties in verifying samples. a taxonomic review of the fungus is now available (see later section) a similar review is required for ganoderma (e.g. see paterson, 2006 . larval infection via meiotic and/or mitotic spores/conidia and multiplication within the insect is from yeast-like budding. however, the fungus grows through the insect by hyphae. the accumulation of the biomass eventually kills the host (and/or a toxin(s) may be involved). it would be interesting to determine the biochemical parameters that cause these changes but this is not reported in the literature. the fungus ruptures the host body following over wintering and forms the sexual perithecial stroma that are connected to the dead larva below ground which grow upward to emerge above the soil surface (fig. 1) . the complete insect/fungus combination is used traditionally, but not exclusively, for medicinal purposes. the present reviewer has seen no reports of the insect per se being given as a treatment. c. sinensis (berk.) sacc., is one of the most famous traditional chinese medicines (tcm) and health foods. the fungus parasitises larvae of moths (lepidoptera), especially hepialus armoricanus (and thitarodes), and converts each larva into a sclerotium, from which the stroma and fruitbody grows. the complex (including the larva body) has been used as a health food and traditional medicine to ''invigorate the lung and nourish the kidney" in china for hundreds of years, and at least from the 17th century (dong and yao, 2007; kuo et al., 1994) . although what these preparations actually represented is impossible to determine given the difficulties in taxonomy of even modern times (burnett, 2003; korf, 2005 ; and see sung et al., 2007) . understandably, conservation and sustainable harvest are important issues. there is need for (a) research on biological screening, (b) a better understanding of the status in natural habitats, and (c) artificial cultivation of the fungus. cordyceps and products are available in ''western" countries as over-the-counter medicine/tonics which advertise them as chinese herbs with anti-aging, ''pro-sexual", anti-cancer and immune boosting effects, although with poor supporting scientific evidence. the believe is that c. sinensis (cs) has various beneficial effects on humans, including those of a psychological nature. the ftcm, is also called dong chong xia cao in chinese (=winter worm summer grass) (li et al., 2006a) . primarily it is prescribed as a tonic for body strengthening after serious disease. more recently other treatments have been claimed such as for (a) respiratory, renal, liver, nervous system and cardiovascular diseases, and (b) tumours, aging, hyposexuality and hyperlipidemia (kuo et al., 2006; chen et al., 2006; wang and shiao, 2000) . it has been officially classified as a drug in the chinese pharmacopoeia since 1964. furthermore, the outbreak of the severe acute respiratory syndrome (sars) in china in 2003 has increased use considerably. this would have been an excellent opportunity to have determined how effective it was. however, this does not appear to have been undertaken. the market demand for cs is growing sharply in many countries (dong and yao, 2007) . they would surely be hailed as medical breakthroughs if the efficacy of any of these treatments were confirmed. nevertheless, the identities of active components have not been determined (in all cases) (li et al., 2006b) . research has shown that at least some of the traditional uses ''may" relate to pharmacological activities (zhu et al., 1998a,b) (if not pharmacological activities then what?). herbs have been used throughout history to enhance physical performance, but scientific scrutiny with controlled clinical trials has only recently been used to study such effects (bucci, 2000) . the authors mention that cordyceps remain untested which is surprising given the interest in the fungus. the fungus is endemic to the alpine habitats of the tibetan plateau above 3000 m in south-western china, and there has been large-scale harvesting of the wild material from nepal and india more recently. it is agreed generally table 2 example of the range of species and some of the low molecular-weight secondary metabolites from cordyceps secondary metabolites c. sinensis cyclic peptides, h1-a c. militaris cyclic peptides, cordycepin, 10-membered macrolides, cepharosporolides c, e and f, pyridine-2,6-dicarboxylic acid and 2carboxymethyl-4-(30-hydroxybutyl) furan, dipicolinic acid c. pseudomilitaris bioxanthracenes c. brunnearubra cordyformamide c. sinclairii (2s,3s,4r)-(e)-2-amino-3,4-dihydroxy-2hydroxymethyl-14-oxoeicos-6-enoic acid c. cicadae ergosterol peroxide c. nipponica cordypyridones a and b c. ophioglossoides ophiocordin, glycoprotein containing nacetylgalactosamine c. heteropoda cicadapeptins i and ii, myriocin the number of compounds is small compared to that for ganoderma (paterson, 2006) . to have been over-harvested. furthermore, the price of natural products of cs is over us$ 12,000 kg à1 (2006 prices) for only ''average quality" (how this is determined is not clear) in the market and increasing (sharma, 2004) . so one can understand the pressures on supply. the socioeconomic implications of the ftcm are highly significant to the regions where it is harvested. the fungus has officially been classified as an endangered species by cites management authority of china and china customers and this scarcity is of considerable concern to all. consequently, living strains have been isolated from natural cs and cultivated in large quantity by bioreactor technology which is a promising method to meet the needs of human consumption and to reduce the pressure on natural resources of the species (dong and yao, 2007) . in vitro culture of the fungus has been employed increasingly and yang et al. (2005) state, ''it is generally accepted that its cultivated cs fungi possess the same functions as cs natural ''herbs" (sic)". some other issues that require addressing are that natural c. militaris is not readily available and is costly. thus, a growing number of socalled cordyceps products that derive from mycelial cultures of the asexual forms of these fungi have become commercially available (hamburger, 2007) . mycelia cultivation has resulted in establishing a number of cultures derived from the holomorphic cs. these are referred to by the anamorphic names paecilomyces hepiali and cephalosporium sinensis, although the anamorph of cs appears to be hirsutella sinensis (and see later). however, the situation is confused with some taxonomist using outdated names. to paraphrase buenz et al. (2004 buenz et al. ( , 2005 : while these strains undoubtedly support ecologically sustainable use of cs, the actual similarities between the wild fungus and the cultures are not clear. the consumption of complimentary medicine has increased dramatically, with over 42% of people in the united states of america reported as ''users". sales were us$ 3.3 billion in 1999 (buenz et al., 2005) . an important factor was the passage of the dietary supplement health and education act in 1994 in the usa which opened the market for tcm (cooper and chang, 2001) . one can appreciate how journals advocating these have increased concomitantly. why have they not been developed by big pharmaceutical companies and made available to the public in pure compound form? no doubt there could be many reasons why this has not happened (e.g. not enough profit, ''sticky" intellectual property rights issues (see paterson, 2008) , difficulty in mass production or synthesis, etc.)apart from the possibility that they simply may not be effective. buenz et al. mention that ''one of the most interesting supplements is the not yet well-characterized c. sinensis (berk.) sacc.". cs has attracted much research interest for anti-oxidant activity and there is considerable evidence of this from the fungus as a treatment of a wide range of diseases. however, unauthenticated material has been used in some cases. for example, a polysaccharide was isolated which can protect pc12 cells against hydrogen peroxide-induced neuronal cell toxicity, but the cordyceps mycelia used was from the wan fong pharmaceutical factory (zhejiang, china) and derived from ce. sinensis chen sp. nov. this is a nomenclaturally illegitimate fungal name, which raised doubts as to its relationship to cs. in fact, it was later proved to be a different species (dong and yao, 2007) and this is a specific example of a general problem in the field. an example of another problem is cordymax cs-4, a commercial mycelial fermentation product that lowered fasting plasma levels of glucose and insulin, improved oral glucose tolerance and increased the glucose-insulin index, which measures insulin sensitivity, in rats (zhao et al., 2002) . however, the following statement is given on the web site of the product, ''these (health-related) statements have not been evaluated by the food and drug administration. this product is not intended to diagnose, treat, cure or prevent any disease". extracts from artificially cultivated fruit-bodies of cs from the xinhui xinhan artificial cordyceps factory (guangdong, china) could scavenge ros by inhibiting malondialdehyde formation by the peroxynitrite generator sin-1. these results have been since referred to uncritically (e.g. buenz et al., 2004 buenz et al., , 2005 li et al., 2003) . however, the fungal material may have been unauthentic, because reports exist that cultivation of fruit-bodies of this fungus was not repeatable and that the manufacturer is actually selling c. militaris. furthermore, li et al. (2001) compared the anti-oxidant activities of natural cs and cultured cordyceps mycelia from different sources and were able to show the similar effects of the cultured mycelia to the natural products. however, the cultured material used was derived from a wide range of strains, and not from a valid cs. some of these were products from the chinese medicine factory of jiangxi and hebei boding pharmaceutical factory. in addition, the ftcm are boiled in water or soaked in alcohol to drink for medications/health foods. obviously, the various solvents and temperatures may have resulted in different compounds (dong and yao, 2007) . nevertheless, guo et al. (2007) state that the ongoing exploration of cs has shown that the species can produce ''many" bioactive compounds, and the medicinal benefits of cs have been demonstrated extensively. in addition, there is (unbelievably for scientific journals) the use of words such as ''yin" and ''yang" as a basis for undertaking scientific research on material activities. canney (2006) discusses kidney ''yang" and one needs to ask what this is from a scientific perspective. why include this word when it has no scientific currency? the fungus is also referred to as a herb and indeed the title of the piece asks, ''c. sinensis animal, vegetable or both?", whereas it is neither. various bioactive constituents from cordyceps species have been reported. these include cordycepin and other anti-bacterial and anti-tumour adenosine derivatives, ophicordin, an anti-fungal agent, and l-tryptophan. recent reports have indicated that cs contains polysaccharides exhibiting anti-oxidant activity and nucleosides that inhibit platelet aggregation (wu et al., 2005) . the bioactive compounds involved in the activities claimed include polysaccharides, modified nucleosides, and cyclosporin-like metabolites which are produced by this fungus and related species. the beneficial effects on (a) renal and hepatic function and (b) immunomodulation-related anti-tumour activities are most promising and deserve great attention. an increasing number of studies have used cultured mycelia in investigations. more mechanism-based, disease-oriented pharmacological studies are required to ensure clinical efficacy for particular diseases. however, pang et al. (2002) state revealingly that studies have demonstrated repeatedly that many natural products marketed as nutraceuticals or health food do not deliver the health benefit as claimed and are inconsistent from batch to batch. in the popular mind, cs first gained worldwide attention when it was revealed that several chinese runners who broke world records in 1993 had included this fungus in their diet as part of their training program. although scientist need to desist from quoting such reports as they are unsubstantiated and far-fetched. purported and unsubstantiated effects of the fungus include use as an aphrodisiac, analgesic, immune modulator, and free radical scavenger. a review of the literature uncovers the predictable collection of general papers concerning medical mushrooms some with a distinctly ''alternative" flavour. i have no concerns about being alternative but are they scientific? these overviews often are written in breathless, overblown and unscientific terms; others are well balanced. dasilva (2005) talks about ''novel mushroom-based healthcare products and therapeutics licensed for medical use can contribute to the good health status and feeling of the povertystricken strata of urban societies and populations. indeed, mushroom cultural practices and medicines are being widely accepted as the integral skeins in the fabric of the human society of tomorrow". a valid response to this situation of a wide range in the quality of papers would be to only review those papers that have a high impact factor (or any impact factor). temporarily putting the debate about the value of impact factors to one side, the reader may find it beneficial to concentrate only on those journals reviewed herein that do indeed have such ratings. of course, the disadvantage is that valuable information may be missed. it may be worth mentioning that, asian nations on the world stage have realised that biomedicine offers a unique chance to develop new industries and markets. universities in singapore, korea, hong kong and china are appearing concomitantly in world tables for the best and citations data suggest they are producing well-regarded papers (ince, 2007) . the following review concentrates on the biological activity of various preparations of cordyceps spp. (the name as used in the essentially non-taxonomic papers) because of the quantity of data and importance of medicinal claims, at the expense of taxonomic and quality control issues. the various pure compounds, extracts, whole fungus and other preparations as they relate to pharmacological activities are discussed next, as these divisions are considered to be most relevant to a biochemical/phytochemical perspectives of the topic. data from pure compounds are the most revealing in terms of determining effects of the fungus/insect. it is noted that these reports are scarce. some compounds from cordyceps (as defined here) are not particularly unusual. ng and wang (2005) review the chemical constituents and pharmacological properties. the chemical constituents include (a) cordycepin (3 0 -deoxyadenosine) and its derivatives, (b) ergosterol, (c) polysaccharides, (d) a glycoprotein and (e) peptides containing a-aminoisobutyric acid. the activities ascribed to the fungus are anti-tumour, antimetastatic, immunomodulatory, anti-oxidant, anti-inflammatory, insecticidal, anti-microbial, hypolipidaemic, hypoglycaemic, anti-aging, neuroprotective and renoprotective effects: so a vast a range of properties from a narrow spread of compounds. polysaccharides account for the anti-inflammatory, antioxidant, anti-tumour, anti-metastatic, immunomodulatory, hypoglycaemic, steroidogenic and hypolipidaemic effects. cordycepin contributes to the anti-tumour, insecticidal and anti-bacterial activity. ergosterol (a universal fungal compound) exhibits anti-tumour and immunomodulatory activity. finally, a dnase has been characterized. these are not particularly novel compounds and one wonders why there are so many reports of the effects of crude extracts rather than much more work on the effects of novel pure compounds. cordycepin (fig. 2) , 3-deoxyadenosine, is a derivative of the nucleoside adenosine differing from the latter by the absence of oxygen in the 3 0 position of its ribose entity. as such is may be quite common. initially, it was extracted from cordyceps; however, it is now produced synthetically. some enzymes do not discriminate between adenosine and so it can participate in certain reactions. for example, it can be incorporated into rna molecules causing premature termination of its synthesis. it is classified as an anticancer compound. cordycepin inhibited the growth of clostridium paraputrificum and clostridium perfringens, but had no effect on bifidobacterium spp. and lactobacillus spp. (ahn et al., 2000) . in addition, larvicidal activity against plutella xylostella after 2-4 days of treatment was observed . it is interesting that cordycepin, a compound originally isolated from c. militaris as much as 60 years ago (cunningham et al., 1950) , is known to exert cytotoxic effects through nucleic acid methylation (kredich, 1980) , with possible implications for the pcr of these fungi (see paterson, , 2008 . if it is a truly useful compound it is surprising that it is not a well-known pharmaceutical by now. the presence of cordycepin in cs has been difficult to confirm, although it has been confirmed by nmr (chen and chu, 1996) . however, other groups have not been able to detect this compound . it is clearly important to confirm the presence of the compound in cs in terms of determining the active components of the fungus and ultimately for chemotaxonomic purposes. cho et al. (2007) state that cordycepin is isolated from c. militaris and is (claimed to be) an ingredient in tcm which is prescribed for various diseases, such as cancer and chronic inflammation (again note how vague this verbatim statement is). in this study, the novel effect of cordycepin inhibiting collagen-induced platelet aggregation was reported. the data suggests that the inhibitory effect of cordycepin might be associated with the down-regulation of [ca 2+ ]i and the elevation of camp/cgmp production. this result has obvious significance for prevention of thrombus formation. finally, cordycepin inhibited the growth of b16 melanoma cells inoculated subcutaneously into right murine footpads (yoshikawa et al., 2004) . cordyheptapeptide a (fig. 3) , a novel cycloheptapeptide, was isolated from a strain of cordyceps together with four known bioxanthracenes. there were only two previous reports on the isolation of cyclic peptides from this genus and these were from c. militaris and cs. the metabolite exhibited anti-malarial activity against plasmodium falciparum and cytotoxicity to vero cell lines. also, the anti-malarial and cytotoxic activities of the bioxanthracenes were reported (rukachaisirikul et al., 2006) . in an extensive and impressive report, compounds designated as es-242s, were isolated from a verticillium strain and identified as bioxanthracenes (isaka et al., 2007a) . these compounds were known to exhibit potent activity as n-methyl-d-aspartate (nmda) receptor antagonists. in addition, five novel es-242 analogues were isolated with nine known compounds from a cordyceps strain. a closely related strain provided cordyheptapeptide a, cordyheptapeptide b, and known es-242s. the structures of the novel bioxanthracenes were 6 0 -o-desmethyl analogues of the compounds described. furthermore, cordyheptapeptide b has an n-methyl-l-phenylalanine residue in place of the n-methyl-l-tyrosine. the isolation, structure elucidation, and anti-malarial activity of es-242s and their analogues from the insect pathogenic fungus cordyceps pseudomilitaris (from a lepidoptera larva) were reported previously. cycloheptapeptide, cordyheptapeptide a, and some known es-242s were isolated from a cordyceps strain from an elaterid larva. in a continuing search for bioactive compounds from insect pathogenic fungi it was noticed that culture extracts of six cordyceps strains, collected in the same location (from coleoptera larvae, at doi innthanon national park, chiang mai province, thailand), showed similar 1h nmr spectra. this suggested the presence of bioxanthracenes (es-242s) and cordyheptapeptide a as major constituents. two of these strains were subjected to mass fermentation (15 l) and chemical investigation. as a result, five new es-242 analogues and nine known compounds and cordyheptapeptide a were isolated from an undefined strain. cordyheptapeptide b, was isolated, together with other known compounds. some of these were tested for activity against p. falciparum and cytotoxicity to kb cells (oral human epidermoid carcinoma), bc cells (human breast cancer), nci-h187 cells (human small cell lung cancer), and noncancerous vero cells (african green monkey kidney fibroblasts). cordyheptapeptide a exhibited antimalarial activity, while cordyheptapeptide b was inactive and both cyclic peptides showed moderate cytotoxicity. furthermore, cordyformamide is a plausible biogenetic precursor of xanthocillin y, and was isolated from a culture broth of cordyceps brunnearubra bcc 1395. cordyformamide was found to exhibit activity against p. falciparum, whereas it showed weak or no cytotoxicity (isaka et al., 2007b) . production of the nonribosomal peptides cicapeptins i and ii (fig. 4) were reported by krasnoff et al. (2005) which was the first report from fungi of consecutive hyp or pro residues in a nonribosomal linear peptide. the compounds exhibited anti-bacterial and anti-fungal activity. a novel immunosuppressant was isolated from the culture broth of isaria sinclairii, the anamorph of c. sinclairii, and characterized as (2s,3s,4r)-(e)-2-amino-3,4-dihydroxy-2-hydroxymethyl-14-oxoeicos-6-enoic acid, which was identical to anti-fungal substances, myriocin and thermozymocidin (fujita et al., 1990) . the suppressive activity was found to be equal to, or higher than cyclosporin a which is used clinically. the activities of the 10 derivatives were also examined, indicating the following relationships between structure and activity -the: (a) lactone formation between the carboxy group at c-1 and the hydroxy group at c-4, and the reduction of the carbonyl group at c-14 to the hydroxy group do not affect the suppressive activity; (b) hydrogenation of the double bond at c-6 resulted in activity; and (c) acetylation of the amino group and the thioketalization on the carbonyl group at c-14 ''drastically" reduced the suppressive activity. also, the compound suppressed the production of anti-bodies to sheep red blood cells and induction of cytotoxic lymphocyte t cells more strongly than cyclosporin a. obviously, this is an important lead compound and hence one of the more satisfactory papers. chen et al. (1999) isolated a pure compound (h1-a) from cs and investigated whether autoimmune disease progression in mice was affected by administration of the metabolite. the authors are vague as to what the compound is and state that, ''it is a kind of ergosterol and looks like testosterone". the authors also provide a chemical structure which confirms that it is a common sterol and a systematic name could have been provided. their results demonstrated that mice treated daily exhibited a progressive reduction in anti-ds-dna production. in clinical presentation, the treated group had a reduction in lymphadenopathy, a delayed progression of proteinuria, and an improvement in kidney function. histological analysis of kidney tissue indicated that h1-a inhibited mesangial proliferation that was evident in lupus nephritis. however, there was no change in immune complex deposition. h1-a ''may be" useful for treating systemic lupus erythematosus in human patients. however, more work is required. h1-a was claimed to be effective in the treatment of autoimmune disorders (yang et al., 2003) . results demonstrated inhibition of cell proliferation and promotion of apoptosis of activated human mesangial cells in vitro: the activities were not a result of cytotoxicity. in addition, h1-a inhibited tyrosine phosphorylation of human mesangial proteins. these findings suggest that h1-a modulated some (unspecific) subcellular signal-transduction pathways and changed the balance between proliferation and apop-tosis of mesangial cells in vitro and in vivo. the conclusions were that h1-a may be effective in the management of autoimmune disorders, and the modulation of the signal-transduction proteins may represent a target for future pharmacologic interventions. more correctly, they probably do represent a target, and such vague statements should be avoided. in an older report, hi-a alleviated immunoglobulin a nephropathy (berger's disease) with histological and clinical improvement . hi-a inhibited the proliferation of human mesangial cells and promoted apoptosis by suppressing tyrosine phosphorylation of bcl-2 and bcl-xl (yang et al., 2003) and reduced antids-dna production and lymphadenopathy, delayed progression of proteinuria, improved kidney function and inhibited mesangial proliferation . moving on to more interesting compounds, cordypyridones a and b were detected from the uncommon species, c. nipponica. these are atropisomers, and demonstrated potent anti-malarial activity in vitro (isaka et al., 2001b) . shin et al. (2001) state that, ''in an effort to evaluate the pharmacological effects, including the anti-aging effect" of the fruiting bodies of the cultivated paecilomyces japonica fungus, ''a new type" of cordyceps sp. was investigated. two pure compounds were isolated as active principles from low molecular-weight fractions, and a protein-bound polysaccharide that showed a marked increase in the liver enzyme activities, and a significant inhibition of lipid peroxidation was found. boros et al. (1994) reported that ophiocordin, an anti-fungal antibiotic from cordyceps ophioglossoides (kneifel et al., 1977) and balanol from verticillium balanoides are structurally identical. this may indicate a particularly close taxonomic relationship between the two taxa. the structure of ophiocordin was falsely assigned and balanol was the compound of interest. balanol was under development as an anti-cancer agent as it established to be a selective inhibitor of protein kinase c (see paterson, 2008) . it is more common for pure compounds to be tested in the fields of anti-bacterial, anti-fungal, anti-malarial and insecticidal activity which is to be recommended more generally. ophiocordin is an anti-fungal antibiotic isolated from submerged cultures of c. ophioglossoides. however, it is devoid of anti-bacterial activity (kneifel et al., 1977) . bioxanthracenes (see also previously) were isolated from c. pseudomilitaris (isaka et al., 2001a; jaturapat et al., 2001) and appear to be anti-malarial. ten-membered macrolides, cepharosporolides c, e and f, cordycepin, pyridine-2,6-dicarboxylic acid and 2-carboxymethyl-4-(30hydroxybutyl) furan were reported from c. militaris by rukachaisirikul et al. (2004) . however, only cordycepin was anti-malarial. krasnoff et al. (2005) reported cicadapeptins i and ii (nonribosomal peptides containing aminoisobutyric acid), which were anti-bacterial and antifungal, and myriocin (anti-fungal) from c. heteropoda isolated from an australian cicada. finally, a glycoprotein containing n-acetylgalactosamine was isolated from c. ophioglossoides but activity data are not available (kawaguchi et al., 1986 ). an inhibitor of the prophenoloxidase activation was isolated from a culture filtrate of c. militaris and identified as dipicolinic acid (dpa). the production of dpa in a range of clavicipitaceae fungi was examined. entomogenous fungi that produce dpa were integrated into one group by a phylogenetic analysis based on 18s rdna. interestingly, it was suggested that the group acquired an ability to produce dpa during its evolution from plant pathogenic fungi to entomogenous fungi (watanabe et al., 2006) . in a useful comparison of crude extracts and pure compound, the anti-diabetic effect of various fractions of c. militaris, ccca (crude cordycepin containing adenosine), cmess (ethanol soluble supernatant), and cordycepin were evaluated in diabetic mice (yun et al., 2003) . cmess showed a potent inhibitory activity of 34.7% in starchloaded mice: cmess reduced blood glucose level by 35.5%. however, ccca, and cordycepin showed no difference. after 7 days administrations of these drugs, cmess, and cordycepin dramatically reduced blood glucose level. ccca with a high concentration of cordycepin did not reduce blood glucose level. proliferation of t-lymphocyte was significantly decreased; while no production was increased more than two-fold in the cordycepin-administered group. the proliferation of macrophages and no production were significantly decreased in the cmess administered group. cmess and cordycepin may be (a) useful tools in the control of blood glucose level in diabetes and (b) promising new drugs as an anti-hyperglycemic agent without the defects of lowered immune responses and other side effects, the authors suggest. furthermore, cordycepin, 3 0 -amino-3 0 -deoxyadenosine, homocitrullyl aminoadenosine, adenine, cordycepic acid and d-mannitol have been reported from cordyceps spp. (cunningham et al., 1950; chatterjee et al., 1957; kredich and guarino, 1961; guarino and kredich, 1963; kaczka et al., 1964; liu et al., 1989) . ergosterol peroxide isolated from c. cicadae inhibited phytohaemagglutinin-induced t cell proliferation, and arrested the progression of activated t cells from g1 to s phase of the cell cycle. early gene transcripts, in particular those of cyclin e, interferon, and interleukins were suppressed (kuo et al., 2003) . the glycosylated form of ergosterol peroxide from cs was more potent than the aglycone in inhibiting proliferation of tumour cells (bok et al., 1999) . however, ergosterol peroxide is widespread in fungi and cordyceps does not offer any particular advantage in its preparation. it is worth noting that eight different cordyceps species (cs. c. militaris, c. cicadae, c. ophioglossoides, c. heteropoda, c. pseudomilitaris, c. nipponica, c. sinclairii) are listed in the above paragraph indicating the extent of the possible diversity involved in the biology and activity (tables 1 and 2) . although whether they are distinct species is open to question. water-soluble crude polysaccharides were obtained from the fruiting bodies of cultured c. militaris by hotwater extraction followed by ethanol precipitation. the polysaccharides were successively purified by chromatography giving three polysaccharide fractions. in the in vitro anti-oxidant assay, p70-1 was found to possess hydroxyl radical scavenging activity. the polysaccharide is a heteropolysaccharide and is occasionally branched. the fundamental information obtained from this work is beneficial to the interpretation in the relationship of polysaccharide structure and its biological functions. this provides the ''experimental evidence and scientific explanation for the folkloric uses of c. militaris as a substitute for cs" (yu et al., 2007a) . the effect of an exopolysaccharide fraction (epsf) from anamorphic strains of cs on the immunocyte activity of tumour-bearing mice was investigated. epsf significantly inhibited the h22 tumour growth, and elevated the activity of immunocytes. it enhanced the phagocytosis capacity of peritoneal macrophages and proliferation ability of spleen lymphocytes. epsf promoted (a) tnf-a expression of macrophages, (b) the cytotoxicity of spleen lymphocytes, and (c) tnf-a and ifn-c mrna expression of splenic lymphocytes . cs possesses anti-tumour, anti-oxidation and stimulation of the immune system activities . however, the identity of active component(s) has not been determined . towards this end, a polysaccharide was isolated from cultured cordyceps mycelia which had strong anti-oxidation activity, and which contained glucose, mannose and galactose. the pre-treatment of the isolated polysaccharide on cultured rat pheochromocytoma cells demonstrated strong protective effect against hydrogen peroxide (h 2 o 2 )-induced insult. treatment prior to h 2 o 2 exposure significantly elevated the survival of pc12 cells in culture. this was the first report that identified a polysaccharide from cordyceps, which protected against the free radical-induced neuronal cell toxicity. a water-soluble polysaccharide fraction, a poorly water-soluble polysaccharide, and a protein fraction stimulated steroidogenesis (huang et al., 2001b) . interestingly, galactomannans isolated from the insect portion of c. cicadae demonstrate potent hypoglycaemic activity in mice (kiho et al., 1990) . in an investigation into a polysaccharide from cs mycelium hypocholesterolaemic and hypotriglyceridaemic activity in mice was exhibited (kiho et al., 1996) . chen et al. (1997) studied a polysaccharide fraction from cs as to its effect on the proliferation and differentiation of human leukaemia cells using an in vitro culture system. the conditioned medium had an activity that significantly inhibited proliferation. differentiated cells also possessed phagocytosis functions and supported superoxide production. antibody neutralization studies further revealed that the tumouricidal and differentiating effects of the compounds were mainly derived from the elevated cytokine concentrations. finally, galactosaminoglycan from c. ophioglossoides reacted with sera from patients with certain collagen diseases and its use as an index of serological activity is thus of diagnostic value (ikeda et al., 1993) . an aqueous extracted polysaccharide from cultured c. militaris demonstrated general anti-inflammatory activity (yu et al., 2004a) as did ethanolic extracts of cultured fruiting bodies and mycelia of c. militaris applied topically in the croton oil-induced ear oedema test in mice. the fact that in vitro fruiting bodies were employed rather than in vivo is interesting as most papers report using fruiting bodies in vivo and/or in vitro biomass. however, the paper is flawed as the details of the cultivation of the fruiting bodies were not provided. antioxidant activity in the xanthine oxidase, haemolysis and lipid peroxidation assay systems was demonstrated by li et al. (2001a) from water extracts, and a polysaccharide fraction, of cultured cs mycelia. interestingly, the fruiting body and the caterpillar parts of cs are claimed to be similar in chemical composition and hence anti-oxidant activity, because the fungus had presumable replaced the insect constituents with fungal . it would be interesting to determine (a) how this occurs in terms of insect substrate utilisation and optimisation of yields of bioactive fungal components, (b) when the preparation is at the correct stage for use as a medicinal treatment, and (c) if these data could be extrapolated to in vitro culture. an ambiguous statement is made by shin et al. (2001) , ''cordyceps is negative for its many biological activities and a tonic for restoring vital functions in traditional chinese medicine". it proceeds to state that p. japonica is a new type of cordyceps species, which is incomprehensible. it also mentions that p. japonica is (or produces) mushrooms. paecilomyces is considered to be an anamorph of cordyceps and so this appears to be incorrect and, what appear to be mushrooms, may be synnemata (compacted conidiophores). however, it is unwise to speculate what the material actually is as descriptions are vague. a protein-bound polysaccharide that inhibited lipid peroxidation and increased the activity of anti-oxidant was described from the fungus. finally, phaeochromocytoma cells were protected against h 2 o 2 -induced injury by a 210-kda polysaccharide from cs mycelium . yamada et al. (1984) reported that a water-insoluble extracellular glucan isolated from the culture filtrate of c. ophioglossoides suppressed potently the growth of sarcoma 180 solid-type tumours. remarkably, a protein-bound polysaccharide fraction from c. ophioglossoides extended the life of mice bearing ehrlich carcinoma or a syngeneic tumour . also, ohmori et al. (1989a,b) isolated a galactosaminoglycan that inhibited the proliferation of sarcoma 180 cells and the growth of a syngeneic solid tumour in vivo: it exhibited cytotoxicity against cancer cells in vitro. chen et al. (1997) observed that medium from blood mononuclear cells stimulated with the polysaccharide fraction from cs inhibited the proliferation of human leukaemic cells, and induced approximately 50% to differentiate into mature monocytes/macrophages expressing non-specific esterase activity and certain surface antigens. the anti-proliferation and differentiating effects were demonstrated to be caused by an elevated production of cytokines, i.e. a tumour necrosis factor and an interferon. the exopolysaccharide fraction of cs inhibited metastasis of melanoma cells and down-regulated concomitantly the levels of bcl-2 protein into the lungs and the liver . the exopolysaccharide fraction of cultivated cordyceps stimulated peritoneal macrophages to take up neutral red and splenic lymphocytes to proliferate . crude and neutral polysaccharides of cs exerted hypoglycaemic activity in normal mice. however, the polysaccharide did not affect the circulating insulin level in normal mice (kiho et al., 1993) . the compound lowered the plasma glucose level in diabetic mice (kiho et al., 1996) . another unspecific polysaccharide from a hot-water extract of mycelia also lowered the plasma glucose level in normal, adrenaline-induced hyperglycaemic and diabetic mice (kiho et al., 1999) . some cordyceps-like strains have been isolated from the fruiting bodies of wild cs that have been reported to show the same properties as the natural product. however, care in interpretation is required as these could conceivably be contaminants (see later). an exopolysaccharide fraction was prepared from cultivated cs . the results showed that it enhanced significantly the neutral red uptake capacity of peritoneal macrophages and spleen lymphocyte proliferation in melanoma-bearing mice. the metastasis of b16 melanoma cells to lungs and livers was significantly inhibited. moreover, the levels of bcl-2 in the lungs and livers were decreased. the results suggest that the polysaccharide has an immunomodulatory function and anti-tumour activity. however, yang et al. (2005) state that although certain polysaccharides from cs are bioactive, the anti-tumour effect has not been confirmed. the authors investigated the effects of the exopolysaccharide fraction of cultivated cs fungus on c-myc, c-fos, and vascular endothelial growth factor (vegf) expression of tumour-bearing mice. the expression in the lungs and livers of treated mice were found to be significantly lower than those of untreated mice. the authors suggest that the fraction had inhibited tumour growth in the lungs and livers of mice, and that it is an adjuvant in cancer therapy. in addition, yu et al. (2004a,b) isolated four polysaccharides from c. militaris, cps-1 was shown to possess a significant anti-inflammatory activity and suppressed the humoral immunity in mice but had no significant effects on cellular immunity and non-specific immunity. in a previous study using anti-oxidant activity-guided fractionation csp-1 from cultured cordyceps, mycelium was isolated. the hypoglycemic effect of csp-1 on mice and rats was demonstrated. csp-1 increased circulating insulin level in diabetic animals, which suggests that the compound(s) may stimulate pancreatic release of insulin and/ or reduce insulin metabolism. chen et al. (2006) undertook further work on the biological activity of the isolate: the polysaccharide from fungus and its anti-oxidant activity on h22-tumour bearing mice was investigated. the h22 tumour growth was inhibited and sod activity of liver, brain and serum and gsh-px activity of liver and brain in tumour-bearing mice were enhanced. in general, beneficial effects were observed in the liver and brain of tumourbearing mice. finally, four exopolysaccharides with different molecular masses ranging from 50 to 2260 kda were reported from c. militaris by kim et al. (2003b,c) as part of yield optimisation studies. an extracellular polysaccharide extracted from the mycelia of cs with hot-water indicated that this d-glucan consisted of a backbone composed of (1 ? 3)-b-d-glucosyl residues and carried a single (1 ? 4)-b-linked d-glucosyl residue: sugar residues were linked with b-glycosidic bonds (wu et al., 2005) . a lectin from c. militaris exhibited hemagglutination activity in mouse and rat erythrocytes, but not in human abo erythrocytes (jung et al., 2007) . however, the n-terminal amino acid sequence differed greatly from those of other lectins. it exhibited mitogenic activity against mouse splenocytes. the following section concerns solvent extraction of the fungi. in effect, this is often how the preparations will be consumed as a tcm. the significance of tests on extracts is much reduced compared to those of pure compounds. there is a great deal of data. in general, this type of work needs to be deemphasised in favour of that of pure compounds. reports on the metal chelating and reducing power from cs are not available in the scientific literature. therefore, there is a demand to obtain an overall measure of the anti-oxidant activity of extracts using reliable fungal material because of increasing interest in the relationship between anti-oxidants and diseases. the anti-oxidant activities from natural and cultured mycelia of cs were investigated in vitro. optimal effects were demonstrated on the inhibition of linoleic peroxidation. the results suggested that the cultured and natural mycelia have direct and potent activities and that the cultured mycelia could be used for the anti-oxidant activity which would tend to reduce the pressures on the natural fungus, which is, after all, an endangered species (dong and yao, 2007) . the anti-oxidant efficiency of c. militantis extract (cme) and cs extract (cse) in protecting lipid, protein, and lowdensity lipoprotein (ldl) against oxidative damage was reported (hui et al., 2006) . however, this study provoked a strong response from hamburger (2007) which was subsequently rebutted by one of the original authors (duh, 2007) . this is something of an unexpected bonus to a reviewer of the literature such as myself as another opinion is obtained. the questions are, what biological material is being worked with, and can other scientists obtain it to repeat the experiment? the current author has encountered this before (paterson, 2005) where commercial interests are involved. the hamburger response can be applied in a general sense to some of the other work cited in the present review. cme and cse showed weakly inhibitory effect on liposome oxidation. the inhibitory effect of cme on protein oxidation was inferior to that of cse. cme and cse showed inhibition of ldl oxidation. the contents of the bioactive ingredients cordycepin and adenosine in cme were higher than those of cse; however, cordycepin and adenosine showed no significant anti-oxidant activity. in addition, a polysaccharide present in cme and cse displayed anti-oxidant activity. the authors concluded that the protective effects of cme and cse against oxidative damage of biomolecules are a result of their free radical scavenging abilities. however, the experimental data and some of the conclusions need a critical comment (hamburger, 2007) . the author criticised the report on the bases of poor taxonomy, biochemistry and extrapolation of data to imply possible cures of diseases. in particular, the authors' claims of a potential treatment for human disease on the basis of in vitro data are called into question. the rebuttal by duh simply confirms that appropriate information about the strains was not provided; the comments on the inadequate analytical procedures are largely accepted. and there is no doubt that the conclusions could have been rewritten to indicate that the results were preliminary. hamburger (personal communication, 2007) stated that the rebuttal was evasive, an assessment with which i agree. kuo et al. (2005) describe the effects of cs against group a streptococcus infection in mice. the preparation protected by decreasing bacterial growth ''and dissemination", thereby increasing mouse survival rate. il-12 and ifn-gamma expression and macrophage phagocytic activity also increased. kuo et al. (2007) claim to demonstrate that cs increased phagocytosis in human monocytic cells and abrogated inhibition of phagocytosis by causing cytokine production. these two reports are sound and in good journals. however, the fungus used was from a company called simpson biotech and very few or no details are supplied about how the material was collected, identified, maintained, and grown. of course, this is unsatisfactory. shahed et al. (2001) refer somewhat unusually to cs as a ''black blade" fungus. their results showed that cs improved renal function and reduced the expression of inflammatory and apoptotic genes in rats. the authors make the very conditional statement that, cs extract may play a potential therapeutic role in renal transplantation"; on the other hand it may not play an actual role. after all, precision in what is written in such important areas of medicinal research is crucial. the authenticity of the fungal material can be questioned: it was obtained from a company from the united states of america and there is little indication about the standards of collecting, purity, identities and maintenance of the materials. basically, what level of accreditation applies to such organizations? a c. militaris inhibited the growth of human umbilical vein endothelial cells (huvec) and ht 1080 cells. it down-regulated, in dose-and time-dependent manners, bfgf gene expression in huvec cells and mmp-9 gene expression in ht 1080 cells. the growth of melanoma cells in mice was suppressed. in addition, anti-angiogenic activity was manifested (yoo et al., 2004) . it is gratifying that adequate details of the fungal material are provided in this chinese journal, which acts as a model for others generally. chiou et al. (2000) observed a hypotensive effect of cs in anaesthetized rats and a vaso-relaxant effect in isolated aorta. the fungus counteracted arrhythmia in rats and increased the dosage of ouabain required to produce arrhythmia in guinea-pigs. in addition, the heart rate in anaesthetized rats and the contractility of isolated papillary muscle or atria in guinea-pigs were decreased (mei et al., 1989) . cultured fruiting bodies of cs prevented deposition of cholesterol in the aorta of atherosclerotic mice by inhibiting free radical-mediated ldl oxidation in an investigation into hypolipidaemic activity (yamaguchi et al., 2000a) . a hot-water extract of mycelia (a) lowered the total cholesterol concentration, (b) reduced the concentration of cholesterol carried by ldl and very-low-density lipoprotein, and (c) elevated the high density lipoprotein (hdl)-cholesterol concentration in the serum of mice fed a cholesterol enriched diet (koh et al., 2003a) . water extracts of cs: increased survival time of mice inoculated with carcinoma cells or syngeneic fibrosarcoma cells (yoshida et al., 1989) ; inhibited spontaneously liver metastasis of carcinoma cells and melanoma in syngeneic mice and results suggested that the activity was not attributable to cordycepin (nakamura et al., 1999a) ; prolonged the survival period of mice inoculated with b16 melanoma cells when coadministered with methotrexate (nakamura et al., 2003) and caused apoptosis of melanoma cells (nakamura et al., 1999b ). an orally administered cs was considered to be ''quite" safe based on body weight gain, and liver/kidney weights of mice (nakamura et al., 1999a,b) . the authors concluded the extract could inhibit aortic cholesterol deposition in atherosclerotic mice by scavenging free radicals in vivo. these extracts ''may have" beneficial effects on the process of atherogenesis and aging with few side effects (yamaguchi et al., 2000a) . this is good news but surely more evidence is required. towards these ends, tsai et al. (2001) also demonstrated the hydroxyl radical scavenging activity of cs. whereas reduced lipid peroxidation in rats was demonstrated by shen and chen (2001) . antioxidant activity in the xanthine oxidase, haemolysis and lipid peroxidation assay systems was reported from water extracts, and a polysaccharide fraction, of cultured cs mycelia (li et al., 2001a) . as mentioned previously, the fruiting body and the caterpillar parts of cs are claimed to be similar in chemical composition and hence anti-oxidant activity . it would be interesting to determine (a) how this occurs in terms of insect substrate utilisation by the fungus with a view to optimising yields of bioactive fungal components, (b) when the preparation is at the correct stage for use as a medicinal treatment, and (c) if these data could be extrapolated to in vitro culture. cho et al. (2003) and wang et al. (2005) also reported radical scavenging activity with wang et al. reporting activity against colorectal tumour cells. the influence of cs on the immunoactivity of macrophages was determined to probe the mechanism of its alleged tonic effect. the phagocytosis of macrophages were enhanced significantly (jia and lau, 1997) and ''maybe" the tonic effect of cs is accomplished by an enhancing effect on the immune system. some chemical fractions had insulin like and insulin release promoting activity and ''could be developed" as an anti-diabetic agent (young et al., 2001) . cordyceps possessed a strong anti-oxidation activity in all assays tested by li et al. (2001a) . the cultured cordyceps mycelia had equally strong anti-oxidation activity compared to in vivo cordyceps. further, the anti-oxidation activities were increased â10-30 in the partially purified polysaccharide fractions. in an intriguing report, liu et al. (2006) mentions that identification of an effective non-toxic biological radioactivity protector is a ''matter of some urgency". orally administered cs protected mice from bone marrow and intestinal injuries after total-body irradiation. the levels of free radical species within cells are suggested to be a likely mechanism for the purported effects. the biochemical mechanisms of anti-proliferative effects of c. militaris in human leukemia cells were investigated in a convincing study involving cancer treatment . it was found that they inhibited cell growth in a dose-dependent manner, which was associated with morphological change and apoptotic cell death such as formation of apoptotic bodies and dna fragmentation. furthermore, the treatment caused a dose-dependent inhibition of cyclooxygenase-2 (see paterson, 2008) and prostaglandin e2 accumulation. taken together, these results indicated that the anti-proliferative effects were associated with the induction of apoptotic cell death through regulation of several major growth regulatory gene products. the extracts ''may have therapeutic potential" in human leukemia treatment. in addition, corticosterone output by cultured rat adrenocortical cells was increased without increasing the intracellular camp level. the steroidogenic effect was abolished by the protein kinase c inhibitor calphostin c, indicating that its action may involve stimulation of protein kinase c (wang et al., 1998) . c. militaris reduced the fasting serum glucose level and enhances glucose utilisation in skeletal muscles in rats . the fungus demonstrated cytotoxic activities on the three kinds of human cancer cell lines, stomachic adenocarcinoma, colorectal adenocarcinoma, and hepatocellular carcinoma (lim et al., 2004) . cytotoxic activity-guided isolation and identification of active fractions afforded the well-known, cordycepin as an active component (see above). koh et al. (2003b) reported that cs mycelia prolonged swimming endurance capacity and produced an anti-fatigue action in mice. cs reduced the hepatic content of malondialdehyde and the serum concentrations of transaminases and alkaline phosphatase in rats with hepatic fibrosis. treatment with the extracellular biopolymers resulted in a reduction in hepatic hydroxyproline content and normalization of morphological characteristics of the liver, indicating an anti-fibrotic action (nan et al., 2001) . finally, crystals of the fungus stimulated proliferation of erythroid progenitor cells in mouse bone marrow . in a very interesting report, the insect-body part (of the tcm) inhibited proliferation of enhanced human mononuclear cells (hmnc). any differences between the fungus and insect components are well worth further investigation. the production of interleukin-2 and interferon was stimulated by the aqueous methanolic extracts and inhibited by the methanolic extracts (weng et al., 2002) . treatment of patients with condyloma acuminata brought about an increase in interleukin-2 and a decrease in interleukin-10, indicating a recovery in the balance of th1/th2 cytokines. recurrence was also diminished (gao et al., 2000) . interestingly, the ergosterol esters concentrations were much higher in the (dead) caterpillar than the fruiting bodies (yuan et al., 2007) although ergosterol was similar. although why these compounds are of particular interest is ''mystifying" as they are universal in fungi. in a surprising paper, the following may be an example of the mystical nature of some of the reports (see paterson, 2006) . it represents a bizarre rational for undertaking the work and it is surprising that it was published from a scientific perspective. the rational for the work is that cs is a popular chinese tonifying herb, and was/is revered for being, what is referred to as, 'yin-nourishing' and 'yanginvigorating' in chinese medicine (siu et al., 2004) . in order to establish the pharmacological basis for the 'yinnourishing' and 'yang-invigorating' action of cordyceps, the effects of wild and cultured cordyceps on concanavalin a stimulated splenocytes, an in vitro bioassay for 'yinnourishment', and myocardial atp generation capacity, an ex vivo bioassay for 'yang-invigoration', were investigated in mice. the results indicated that wild and cultured cordyceps enhanced the con a-stimulated splenocyte proliferation in vitro and myocardial mitochondrial atp generation ex vivo in mice, with no significant difference in potency of action between the two types of cordyceps. while the immunopotentiating effect was associated with the increase in interleukin-2 production, the stimulation of myocardial atp generation was paralleled by an enhancement in mitochondrial electron transport. when compared with typical 'yin' and 'yang' tonifying chinese herbs, cordyceps was found to possess both 'yin-nourishing' and 'yang-invigorating' activities, with a lower potency in both modes of action. it is impossible to take reports such as these seriously from a scientific standpoint and is given considerable space here to indicate a general problem which may have motivated some of the published reports reviewed herein. this is without attempting to detract from the philosophical aspects of the concepts of yin and yang in terms of two mutually correlated opposites in a general sense. a comprehensive definition of the corresponding philosophy of science is inappropriate: it is enough to state that it is vitally important for science that the information about the surrounding world and the objects of study be as accurate and as reliable as possible. to continue, cs fruiting bodies inhibited various tumour cell lines (kuo et al., 1994) : two fractions were particularly potent. growth inhibitors other than cordycepin and polysaccharides may have been involved; two fractions significantly inhibited (a) the blastogenesis response, (b) nk cell activity and (c) il-2 production (kuo et al., 1996) . neither fraction was cytotoxic, and immunosuppressive ingredients were found to be intracellular. fruiting bodies inhibited human mesangial cells (hmc) activation by il-1 plus il-6 and liver toxicity or mutagenicity were not observed. the fraction was purified to obtain purified compound h1-a (see above). the authors claim a novel treatment for human berger's disease ''in the future". a fraction (a) dose dependently suppressed bronchoalveolar lavage fluids (balf) cells proliferation, (b) reduced interleukin production in lps activated balf cell cultures and (c) affected interleukin mrnas in various significant manners (kuo et al., 2001) . the purported therapeutic activity may be related to modulation of cells functions in bronchial airways. furthermore, the molecular mechanism of cordyceps pruinosa pharmacological and biochemical actions of macrophages in inflammation has not been clearly elucidated . the authors suggest that an extract suppresses inflammation through suppression of nf-jb-dependent inflammatory gene expression, and hence may be beneficial for treatment of endotoxin shock or sepsis. shim et al. (2000) wrote that they attempted to develop ''a new type cordyceps". to obtain this, they investigated the effects of the fruiting bodies of the cultivated fungus of p. japonica grown on silkworm larvae on hyperglycemia in rats and mice and on immunological functions in mice. as mentioned previously, it is not at all clear whether paecilomyces (even) contains anamorphs of cordyceps. therefore, this report is a cause of some concern. immunostimulating activity and a significant anti-fatigue effect in mice were observed. kuo et al. (1994) reported unidentified substances which inhibited tumour cells, but which were not cordycepin or polysaccharides, in the methanolic extract of cs -this report requires further investigation. c. cicadae ascocarps enhanced hmnc proliferation (weng et al., 2002) . in contrast, the insect-body portion suppressed hmnc proliferation. this is a most interesting result in the current author's opinion because of the different effects of the two components. the action mechanisms of the fractions may involve the regulation of interleukin and interferon production in hmnc. overall, the results demonstrated that c. cicadae contained growth modulators for hmnc. unfortunately, the compounds responsible were not characterised. koh et al. (2002) demonstrated that a hot-water extract modulated interleukin-6 production by activation of macrophages and augmented the secretion of haematopoietic growth factors. whereas aqueous methanolic extracts of the ascocarp stimulated proliferation of phytohaemagglutinin-induced proliferation of hmnc. of course, such differences indicate that different compounds are involved or the same compounds are at different concentrations. c. ophioglossoides mycelia prevented cell death in neuronal cells and memory deficits in rats (jin et al., 2004) . two fractions from fruiting bodies inhibited (a) the blastogenesis response, (b) natural killer cell activity, (c) interleukin-2 production and (d) tumour necrosis factor production in phytohaemagglutinin-stimulated human mononuclear cells (kuo et al., 1996) . the levels of interferon, interleukin-1 and tumour necrosis factor produced by cultured rat kupffer cells were increased by the fungus (liu et al., 1996a) . proliferation of cells in balf was inhibited which also reduced tumour necrosis factor (kuo et al., 2001) . in an effort to evaluate the pharmacological effects, including the anti-aging, of the fruiting bodies of the cultivated p. japonica fungus, a new type of cordyceps sp. was investigated (shin et al., 2001) . this statement by the authors is incomprehensible (see above). types of fungi are the typical specimens often held in culture collections. it is not proposed to discuss the described effects herein. hot-water extracts of cordyceps scarabaecola stromata exhibited potent intestinal immune system-modulating activity, while the methanol-soluble fraction manifested intermediate activity (yu et al., 2003) . xu et al. (1992) detected inhibition in melanoma colony formation in murine lungs by cs. the fruiting bodies of ''p. japonica" reduced tumour weight and volume and lengthened the life span of mice inoculated with sarcoma 180 cells (shin et al., 2003) but what this fungus represents in unclear. water and ethanol extracts of cs possessed a potent anti-oxidant activity (yamaguchi et al., 2000b) . anti-lipid peroxidation activities also were detected and accumulation of cholesteryl ester in macrophages was inhibited via suppression of ldl oxidation. hot-water extracts were particularly effective. ''p. japonica" exhibited immunostimulating activity. its ethanolic extract stimulated phagocyteosis and macrophage acid phosphatase activity (shin et al., 2001 (shin et al., , 2003 . c. militaris demonstrated general anti-inflammatory activity (yu et al., 2004a) in mice. the fact that cultured fruiting bodies were employed is interesting rather than extraction from those from the wild and most papers seen for this review either use fruiting bodies from the wild and/ or in vitro biomass. however, it is disappointing that details of the cultivation of the fruiting bodies are not provided as this is required. nitric oxide production and inos gene expression in lps-stimulated raw 264.7 cells are suppressed by ethanolic preparations (won and park, 2005) . a unique insight into how the cultured fruiting bodies were produced in this report and should be referred to: this detail is required in future reports. cs (as supplied by the ''xinhui xinhan artificial cordyceps factory" (sic)) inhibited mda generation via hydroxyl radicals induced by the peroxynitrite generator sin-1 and macrophage accumulation of esterified cholesterol (yamaguchi et al., 2000a,b) . the authors concluded that the cultured cs has anti-oxidant and anti-lipid peroxidation properties and inhibits accumulation of cholesteryl ester in macrophages via suppression of ldl oxidation. the authors conclude correctly that this cultured chinese medicine appears to merit further investigation as an anti-atherosclerotic. in the unusual use of this solvent to create an extract from cs mycelia, apoptosis in human pre-myelocytic leukaemia hl60 cells was induced. in addition, cell proliferation was inhibited . obviously, ethyl acetate may extract different compounds from the fungus compared to the more common water or methanol extracts and the constituents need to be determined. an alcoholic extract of cs inhibited abdominal aortic thrombus formation in rabbits by preventing platelet aggregation (zhao, 1991) . cs was extracted in pbs and dialyzed (chiou et al., 2000) the resulting macromolecule fraction was assayed in anesthetized rats for hypotensive effects and in isolated aorta for vasorelaxant effects. a constituent(s) in cs relaxed vascular beds directly. the in vivo and in vitro effects and its extracted fractions on the secretion of testosterone in mice were studied (hsu et al., 2003a) . cs, watersoluble protein, and poorly water-soluble polysaccharide and protein significantly stimulated in vitro testosterone production in purified mouse leydig cells. the authors concluded that it is ''possible" that cs ''might" contribute to an alternative medicine for the treatment of some reproductive problems caused by insufficient testosterone levels in human males, which is a large leap in conclusions. increase antigen expression was found in hepatoma cells and ''will" provide more effective host immune surveillance against tumour cells (chiu, 1998 ) from a cordyceps extract. in an interesting study, the beneficial effects of the ''traditional chinese medicine cs", on mice with hypoferric anaemia were evaluated by nmr spectroscopy (manabe et al., 2000) . the extract increased hepatic energy metabolism in anaemic mice and was concluded to be due to increased hepatic blood flow. zhang et al. (2006) concluded that ''their" extract ''is" effective in resisting the oxidative damage on liver mitochondria of diabetic mice. qiao and jian (2007) attempted to identify the signaling pathways for the induction of hl-60 cell apoptosis by cs mycelium extract (csme). csme induced nuclear fragmentation and dna degradation, two hallmark events of apoptosis, in the hl-60 cells within 12-24 h of treatment. concomitantly, several major events in the mitochondrial signal pathway occurred, including (a) the loss of mtp, (b) cytochrome c release into the cytoplasm, (c) the decrease in bcl-2 protein level, (d) the translocation of bax protein from cytoplasm into mitochondria, and (e) the activation of caspase-2, -3, and -9. however, caspase-8, the initiator caspase in the death receptor pathway, was not activated. these results suggest that csme induces apoptosis in hl-60 cell through the mitochondrial pathway rather than the death receptor pathway. treatment of d-galactose-induced-aged-mice with an unspecific cs extract resulted in (a) an improved learning ability and memory, (b) an increase in superoxide dismutase activity in erythrocytes, liver and brain, (c) an increase in catalase and glutathione peroxidase activity in blood, (d) reductions in malondialdehyde levels in brain and liver and (e) a reduction in monoamine oxidase activity in the brain . extracts enhanced the antibody response, restored the phagocytic activity of macrophages in tumour-bearing mice, and lengthened the survival period of the mice (yamaguchi et al., 1990 ). an extract down-regulated apoptotic genes in the rat kidney following ischaemia/reperfusion (shahed et al., 2001) . manabe et al. (1996 manabe et al. ( , 2000 found that a mycelial extract increased hepatic energy metabolism, as demonstrated by liver atp:pi value, in diet-induced hypoferric anaemic mice by increasing hepatic blood flow. the following section considers the use of the fungus as whole mycelium and/or fruit-bodies, although the prepara-tions may have to be prepared in water or ethanol in practise. cs down-regulated inflammation-related genes in the rat kidney following ischaemia/reperfusion (shahed et al., 2001) . a similar treatment improved lung function in guinea-pigs and airway inflammation in rats, suggesting a possible asthma treatment . c. pruinosa inhibited (a) gene expression of an interleukin tumour necrosis factor, (b) inducible nitric oxide synthase (inos) and cyclooxygenase-2, and (c) nuclear transcription factor nf-jb activation in a lipopolysaccharide (lps)-stimulated mouse macrophage cell line: this indicated a role in the treatment of endotoxin shock or sepsis . anti-ds-dna production was inhibited and improved survival in mice indicated that cs may be beneficial to patients with systemic lupus erythematosus, an autoimmune disease with involvement of multiple organ systems . the fungus inhibited lymphadenectasis, reduced proteinuria and plasma anti-ds-dna antibody and improved renal function in mrl 1pr/1pr mice (fu and lin, 2001 ). an oral dose of 2-4 g daily for 3 years prevented the recurrence of lupus nephritis and protected renal function in lupus nephritis patients (lu, 2002) . carcinogenesis in the murine forestomach was suppressed by cordyceps (lin, 1984) . results from liu et al. (1996) indicated that the levels of il-1 and inf, produced by cultured rat kupffer cells were increased from rats fed on cs. studies have demonstrated that polysaccharides extracted from these natural products have anti-hyperglycemic effects (lo et al., 2001) . these authors investigated the effects of intragastrically administered cordyceps sp. for alleviating fasting hyperglycemia in diabetic rats. animals had significantly increased serum levels of triglyceride, cholesterol and blood urea nitrogen, and significantly decreased body weight, serum albumin levels and weights of the thymus, lungs and gastrocnemius muscle compared to animals in the control group. in addition, blood glucose was significantly increased compared to the control group; these results suggest that enterally administered cordyceps sp. has potential anti-hyperglycemic ability. these findings reveal that the fungus ''may be used as a nutraceutical to alleviate hyperglycemia in diabetes". oral administration of cordyceps alleviates fasting hyperglycemia . recent evidence has shown that an extract has immunoregulatory activity. the objective was to investigate whether cordyceps has biological activity in regulating the lymphocyte subsets in diabetes. after 2 weeks, body weight, thymus weight, thymocyte number, and the percentages of total t and t helper cells in the thymus were significantly lower in the treatment groups than in the controls. results demonstrate that stz-induced diabetic rats had significantly decreased numbers and subsets of t cells in the thymus. however, oral administration of cordyceps did not improve these changes. the results suggested that oral administration had no significant effect on lymphocyte subsets in stz-induced diabetic rats. hsu et al. (2003b) demonstrated in a convincing study, that cs mycelium regulates mouse cell testosterone production and may suppress stimulated testosterone production via p450 scc enzyme activity. hsu et al. (2003a) demonstrated that the fungus and fractions from it were capable of stimulating testosterone production. the steroidogenic activity was observed in vivo in male mice after 7 days of treatment (huang et al., 2004b) . chen et al. (2005) found that protein kinase a and protein kinase c pathways are acted upon to stimulate steroidogenesis in ma-10 mouse leydig tumour cells. inhibitors of protein kinase a, protein kinase c and phospholipase c and calmodulin antagonists (see paterson, 2008) reduce leydig cell steroidogenesis induced by the fungus. c. militaris inhibited (a) the growth and metastasis of lewis lung cancer cells, and (b) the growth of sarcoma s180 cells implanted in mice. in addition, the survival period of the mice was increased (liu et al., 1997) . liu et al. (1991) showed that p. sinensis inhibited lipid peroxidation but increases the amount of glutathione peroxidase and superoxide dismutase in mouse liver. again the name of the fungus raises similar questions as to those raised for p. japonica and consequently as to what material is being used and whether the experiments could be repeated. finally, cordyceps is included in a list of anti-aging tcm . cs stimulated mitochondrial electron transport and atp production (siu et al., 2004) . the effect of the fungus on hepatic fibrogenesis induced in rats was studied by liu and shen (2003) . it was found that it delayed cirrhotic development and improves liver function by inhibiting expression of transforming growth factor-and plateletderived growth factor and deposition of procollagen i and iii. zhou et al. (1990) presented evidence for the beneficial effects of cs on chronic hepatitis b. the fungus increased dna synthesis in primary cultured rat tubular epithelial cells (tian et al., 1991) . proximal tubular cells were protected from the toxic effects of gentamicin. the possible mechanisms include protection of sodium pump activity, reduction of lipid peroxidation and attenuation of lysosomal over-activity in tubular cells due to phagocytosis of gentamicin (zhen et al., 1992; li et al., 1996) . also, rat kidneys were protected from cyclosporin-induced nephrotoxicity and ameliorated glomerular and interstitial damage (zhao and li, 1993) . bao et al. (1994) reported that ''old" patients were protected from amikacin sulphate toxicity as demonstrated by decreases in urinary nephroaminoglycosidase and microglobulin. also, inhibition by c. militaris of ldl-induced proliferation of cultured human glomerular mesangial cells, which are involved in the development of glomerulosclerosis was observed (zhao-long et al., 2000) . treatment of mice with c. militaris lengthened the swimming time to exhaustion (jung et al., 2004 ). an unspecified cordyceps is one of the components of fuzheng huayu recipe, which is used to control the development of post-hepatic cirrhosis or to prevent complications from the disease (liu et al., 1996b) . the macrophage-stimulating activity of natural fungus and cultured mycelia has been described by zhang (1985) . zhang and xia (1990) demonstrated immunosuppressant effects in the heterotropic heart allograft model in rats and determined that prolonged survival periods were possible. also, zhu and yu (1990) found prolonged mouse skin allograft survival time. the number of t helper cells was increased, as were lyt-1/lyt-2 (t helper cells to t suppressor cells) in peripheral blood and spleen . a mitogenic action was demonstrated on splenic lymphocytes and interleukin-2 from spleen cells of rats with chronic renal failure was augmented (cheng, 1992) . in addition, natural killer cell activity was enhanced (xu et al., 1992) . treatment of patients with post-hepatic cirrhosis resulted in (a) enhancement of natural killer cell function, (b) increased number and improved ratio of cd4þ and cd8þ cells, and (c) reduction in iga and igg levels (zhu and liu, 1992) . treatment of chronic hepatitis b resulted in increased cd4/cd8 ratios, and reductions in hyaluronic acid and procollagen type iii. the data indicate the usefulness of the fungus in adjusting the level of t lymphocyte subsets and treating hepatic fibrosis (gong et al., 2000) . liu et al. (1992) demonstrated increased peripheral natural killer cell activity from healthy subjects and leukaemia patients. improved renal function and augmented cellular immune function in chronic renal failure has also been observed (guan et al., 1992) . the fruiting body portion, but not the carcass portion, of cordyceps reduced weight loss, polydipsia and hyperglycaemia in diabetic rats (lo et al., 2004) . some other somewhat obscure papers are available on the effect of whole fungi (i.e. peizhong, 1984; chen, 1985; zhang, 1985; shao, 1985; liu and xu, 1985; zhang, 1987; chen, 1987; du, 1986; sun, 1985; li et al., 1993) . feng et al. (1987) reported the vasodilating effect of cultured mycelia of cs in an investigation of the cardiovascular system of dogs. thirty three cases of chronic hepatitis b patients treated with cultured cs mycelia have shown that the drug (a) improves liver function, (b) promotes negative transfer hbsag, (c) markedly helps to raise plasma albumin, (d) helps patients resist high gamma globulin and (e) adjusts body immunocompetence (zhou et al., 1990) . it is suggested that the fungus may be a medicine for chronic hepatitis b patients in adjusting protein metabolism and correcting inversion of albumin and globulin. since inflammation has been reported to be associated with chronic diseases inhibitory dietary factors such as the fungus may be beneficial in alleviating disease (hong and lin, 2004) . 17b-estradiol may directly influence the quality of maturing oocytes and thus the outcome of assisted reproduction treatment. cs mycelium is ''believed" to enhance libido and fertility in both sexes. however, the mechanism of its effect in women has not been determined. this is surely a rather thin basis on which to undertake research. huang et al. (2004a) concluded that treatment of granulosa-lutein cells with cs results in increased 17b-estradiol production due, in part, to increased star and aromatase expression. if these data are confirmed, cs may help in the development of treatment regimens to improve the success rate of in vitro fertilization, they state. zhu and liu (1992) found that cultivated cordyceps mycelia inhibited humoral immune hyperfunction and increase the serum complement level in patients with post-hepatic cirrhosis, and improved liver function. whole body insulin sensitivity in rats was increased (balon et al., 2002) . the fungus increased the basal plasma insulin level (zhang et al., 2003) and inhibited hepatic fibrogenesis in rats with ccl 4 -induced liver fibrosis. previous studies by lo et al. (2006) demonstrated that the fruiting bodies of cs attenuated diabetes-induced weight loss, polydipsia, and hyperglycemia in rats. rats were orally administered, fruiting bodies, fermented mycelia, spent broth, or mycelia plus spent broth of the fungus. the results revealed that the mycelia and spent broth had anti-hyperglycemic activities similar to those of the fruiting bodies. the authors , bold claim that the fermented products could be developed as potential anti-diabetic agents or functional foods for persons with a high risk of diabetes mellitus needs further confirmation. yang et al. (2006) mention that mycelium can inhibit tumour growth and induce tumour cell apoptosis. however, the antitumour mechanisms are not fully understood. so, the molecular mechanism was determined. the authors conclude that cell apoptosis is induced by activating caspase-8-dependent and caspase-9-independent pathways and downregulating nf-jb protein expression. mycelia induced human granulosa-lutein cells to produce 17b-estradiol by upregulating expression of steroidogenic acute regulatory protein (star) and aromatase (huang et al., 2004a) . also, steroidogenesis in mouse leydig tumour cells (huang et al., 2001a) was stimulated without involvement of star (huang et al., 2000) . testosterone production was inhibited by human chorionic gonadotropin or dibutyryl cyclic amp. thus, its effect on the signal-transduction pathway for steroidogenesis may be after the production of cyclic amp. it is revealing to read the web sites of some of the commercial products: these are often written in unscientific terms. the best of them at least contain warnings that, ''these statements have not been evaluated by the (us) food and drug administration. this product is not intended to diagnose, treat, cure or prevent any disease". colson et al. (2005) undertook a revealing experiment to determine the effect on male cyclists' performance using a combination of cs and rhodiola rosea ''herbs" -a tradi-tional herbal medicine. importantly, and unusually, the study followed a double blind, randomized, placebo-treatment, pre-post test design. essentially no effect was observed. this is an example of why scientists need to circumspect about making unsubstantiated claims about the powers of these preparations even if spin does help project funding. ''in this regard, the maintenance of a balance of yin and yang -two opposing components involved in life activities as exemplified by the antagonistic action of the sympathetic and parasympathetic nervous systems-is essential in achieving a healthy condition" (leung et al., 2005) . statements such as these leaves the current reviewer bewildered. why these terms are used in a scientific publication does not appear to merit comment. previous studies have shown that long-term treatment with a ''yang-invigorating" chinese herbal formula (vi-28) could increase red cell cuznsuperoxide dismutase (sod) activity in male human subjects. yet the authors conclude, the beneficial effect of vi-28 treatment on mitochondrial functional ability and antioxidant capacity may have clinical implications in the prevention of age-related diseases. ka wai lee et al. (2006) investigated a commercial preparation of a cultivated strain of cs. they state that the immunomodulatory activities have been renowned for centuries. the report describes positively the immunomodulatory features: in vitro results demonstrated that the fungus induced the production of interleukin (il)-1, il-6, il-10 and tumour necrosis factor alpha, augmented surface expression of cd25 on lymphocytes, and elevated macrophage phagocytosis and monocyte production of h 2 o 2 . the authors state that, ''our results possibly provide the biochemical basis for future clinical trials". the current author emphasises that such over extrapolation of data needs to be discouraged. dai et al. (2001) found that cordymax cs-4 (a mycelial fermentation product of cs) ''improved the bioenergy status" in the mouse liver. these findings may explain why cordymax cs-4 is claimed to alleviate fatigue and improve physical endurance especially in aged subjects. reports of athletes' performance being improved may also be supported from these types of reports. cordymax cs-4 lowered fasting plasma levels of glucose and insulin, improved oral glucose tolerance and increased the glucose-insulin index, which measures insulin sensitivity, in rats (zhao et al., 2002) . an unspecified cordyceps is reported to be a component of fuzheng huayu recipe, which is used to control the development of post-hepatic cirrhosis or to prevent its complications (liu et al., 1996b) . as part of the eternal search to find an excelsior of youth, many are interested in anti-aging activity but it is difficult to define what his means scientifically. are the authors stating that the aging process is slowed for example? do people live longer? in any case, this was published in the journal, chinese journal of integrated traditional and western medicine which is an admirable sentiment but difficult to do in practice. a prep-aration of cs referred to as jinshuibao capsule, increased the depressed superoxide dismutase activity and reduced elevated malondialdehyde (mda) level caused by aging when tested in senile patients. in addition, they enhanced the repair of damaged non human animal dna (zhang et al., 1997) . quite extraordinarily beneficial effects on senile patients are claimed and, of course, the constituents of the capsule may be difficult to verify. zhou and lin (1995) used ''jinshuibao", to restore cellular immune function and ''improve the quality of life" of patients with advanced cancer without affecting humoral immune function. obviously, quality of life is a subjective notion and is difficult to define. remarkably, a dried powder preparation of mycelia called bailing capsule (a) prevented rejection of renal transplants, (b) protected renal and hepatic function, (c) stimulated haematopoietic function, (d) improved hypoproteinaemia and hyperlipidaemia and (e) reduced the incidence of infections (sun et al., 2004) . however, such claims must surely carry considerable elements of doubt. in another case of a combined treatment with as many as six other components in addition to cs, the treatment was more effective at preventing acute renal failure than chronic in rats. obviously, it is difficult or impossible to assess the efficacy of the individual components (ngai et al., 2005) . inhibition of apoptosis is a novel area of clinical investigation with great promise and so merits a separate section in this review and will be of particular interest to pharmacologists. in one of the more critical papers, buenz et al. (2005) mention that there is a wide range of uses of cs in the literature, and those claiming altered apoptotic homeostasis are of the most intriguing. however, they emphasize problems created by the (a) difficulty of identifying the species of cordyceps and (b) many conflicting reports of pharmacological function. in response, the authors (a) outline what is known about the ability of cs to alter apoptotic homeostasis, (b) attempt to reconcile differences in function, and (c) identify the challenges and how to progress cs research. many disorders (e.g. stroke, myocardial infarction and hiv) incorporate apoptosis in their aetiology and pathogenesis. the ability to inhibit apoptosis has emerged as an important potential therapy (e.g. cancer). there are reports of cs extracts inhibiting and inducing apoptosis (shahed et al., 2001) ; this is not contradictory but allows a foundation to determine the molecular mechanism of activity. indeed, cordyceps may contain compounds that inhibit apoptosis; however, conflicting evidence has been obtained. the fungus can scavenge reactive oxygen species by inhibiting malondialdehyde formation by sin-1, the peroxynitrite generator, which has been confirmed by xanthine oxidase, hemolysis, and lipid peroxidation assays. furthermore, an isolated extract of cs, h1-a (this is reported as a pure compound (see above), inhibited induced apoptosis, by permeabilizing the cell membrane and upregulating nitric oxide synthase (trubiani et al., 2003) . on the other hand, extracts of cs did not inhibit hydrogen peroxide-induced apoptosis (buenz et al., 2004) , in a reactive oxygen species model (fauconneau et al., 2002) . alternatively, cs down-regulated apoptotic genes and modulated apoptosis in a rat kidney ischemia reperfusion model. reported anti-apoptotic effects of cs include in (a) the mouse (anti-cytotoxic activity, anti-oxidant activity, cell proliferation inhibition), (b) cell culture (anti-proliferation activity, cell proliferation inhibition, hemolysis inhibitory activity, lipid peroxide formation inhibition, radical scavenging effect), (c) human cells (proliferation inhibition, natural killer cell inhibition, tumour necrosis factor inhibition) and (d) the rat (gene expression inhibition). whereas the reported apoptotic effects of the fungus are in: (a) the mouse (anti-tumour activity, metastasis inhibition) and (b) cell culture (proliferation stimulation, cytotoxic activity). in reality these opposite effects are not incompatible. there are three prominent factors that may contribute to the apparent discrepancies (the first and third are fairly obvious). first, certain fungi contain different biologically active compounds. second, extracts may contain a prodrug; a metabolism step may be required to generate the biologically active form. third, different constituents may be assayed as there are multiple methods of extraction utilized in the literature. furthermore, decreases in fas, fas ligand and tumour necrosis factor expression and decreased caspase-3 activity have been demonstrated (shahed et al., 2001) . cs inhibited tnf-a expression (kuo et al., 1996) . however, when apoptosis was initiated via a fas agonist antibody (ch-11) (alderson et al., 1994) , aqueous and alcohol extracts of cs did not rescue cells induced by fas receptor ligation (buenz et al., 2004) . furthermore, cell cycle arrest and/or inhibition of proliferation yield cells resistant to apoptosis. papers concerning proliferation of leukemic u937 cells and glomerular mesangial cells inhibition (zhao-long et al., 2000; lin et al., 1999) may be explained by conferring a apoptotic resistance to cells: the alteration may involve p53 (fridman and lowe, 2003) or nf-jb (karin et al., 2004) . overall, aqueous, and organic extracts of cs have the ability to inhibit apoptosis. cells pre-incubated with cs extracts were equally sensitive to hydrogen peroxide and fas-mediated apoptosis. thus, the putative antioxidant and anti-apoptotic properties of cs were insufficient to rescue cells from apoptosis in vitro (buenz et al., 2004) . furthermore, cancer chemotherapeutics have involved the ability to induce apoptosis. hence the polysaccharide fraction (h1-a) induced apoptosis by inhibiting (a) phosphorylation of bcl-2 and bcl-xl and (b) apoptosis induced by dimethyl sulfoxide (yang et al., 2003) . these data require to be confirmed by further work (buenz et al., 2005) . finally, direct cytotoxic activity may be a factor (nakamura et al., 1999a,b; kuo et al., 1994; sato, 1989; buenz et al., 2005) . a factor which is not often considered is whether the activities of extracts and pure compounds are from the cordyceps of interest or from other contaminating fungi. the issues of anamorph/teleomorph associations are relevant here. for example, epicoccins a-d were isolated from cultures of a cordyceps-colonizing isolate of epicoccum nigrum (zhang et al., 2007b) . gliocladinins a and b are of an isolate of gliocladium sp. that colonized cs (guo et al., 2007) . it is essential that such activity is differentiated from that obtained from the traditional medicine or cordyceps per se. in a series of papers, (a) paecilomyces militaris is shown to possess militarinones a, b, c, d and (b) farinosomes and a deoxymilitarinone substance were detected from paecilomyces farinosus (schmidt et al., 2002 (schmidt et al., , 2003 cheng et al., 2004 cheng et al., , 2006 . the authors do not make statements as to the holomophic connections to cordyceps. hamburger (2007) does make this link to c. militaris (teleomorph) from p. militaris (anamorph) apparently on the basis of the same pigment production. however, it is has been suggested that paecilomyces does not contain anamophic species of cordyceps . hence, comment on these reports is avoided by the current author because the relationships between paecilomyces and cordyceps remain ill-defined. another complicating facet is that the medicine may contain a proportion of the insect host and so what does this bring to the activity? this is an area of investigation which simply is not reported. indeed does the healthy insect have interesting activities, and/or at what stage does the activity occur in the infected insect? could the activity be greater at these stages? the accumulation of bioactive plant metabolites by insects is well documented (brown and trigo, 1994) and insects are used as medicines . these aspects are almost totally ignored in the case of the medicinal cordyceps. it appears as if entomologists have simply not been involved in the field. does the insect have to be dead before the system works or are more active components produced by the fungus as it is in the process of killing the insect? research into these factors could be fruitful. hence, it is worth reporting what is known about the differences between the insect and fungus parts: interestingly, galactomannans isolated from the insect portion of c. cicadae demonstrate potent hypoglycaemic activity in mice (kiho et al., 1990) . the fruiting body portion, but not the carcass portion, of cordyceps reduced weight loss, polydipsia and hyperglycaemia in diabetic rats (lo et al., 2004) . aqueous methanol extracts of c. cicadae ascocarps enhanced human mononuclear cells (hmnc) proliferation (weng et al., 2002) . in contrast, the methanol (100%) extracts of the c. cicadae insect-body portion suppressed hmnc proliferation. interestingly, the ergosterol esters concentrations were much higher in the (dead) caterpillar than the fruiting bodies (yuan et al., 2007) although ergosterol was similar. finally, the fruiting body and the caterpillar parts of cs are claimed to be similar in chemical composition and hence anti-oxidant activity because the fungus had presumable replaced the insect constituents with fungal . little scientific evidence exists to support the numerous herbs used to improve diabetes-related metabolic disorders (lo et al., 2004) . the dual organism medicine (i.e. fruiting body and carcass) has been proposed to have multiple medicinal activities. in one investigation, the effects of the fruiting body and carcass of the preparation on hyperglycemia were investigated. diabetic rats had significantly lower weight gain and higher blood glucose response in oral glucose tolerance test than the control rats; and these changes were significantly reduced by administrating the fruiting body of cordyceps. the results revealed that the fruiting body (not the carcass) of cordyceps attenuated the diabetes-induced weight loss, polydipsia and hyperglycemia, and these improvements suggest that fruiting body has a potential to be a functional food for diabetes. the water extracts from the fruiting body and ''worm" of natural cordyceps were analyzed for their content of nucleosides and polysaccharides; the results showed that the worm had a chemical composition similar to the fruiting body . in addition, both the fruiting body and worm of cordyceps showed similar potency in their anti-oxidation activities in the xanthine oxidase assay, the induction of hemolysis assay and the lipid peroxidation assay. these results suggest that the function of the worm is to provide a growth medium for the fruiting body, and that eventually, the worm is totally invaded by mycelia. aqueous methanol extracts of c. cicadae ascocarps enhanced human mononuclear cells hmnc proliferation (weng et al., 2002) . in contrast, the methanol (100%) extracts of the c. cicadae insect-body portion suppressed hmnc proliferation. this is a most interesting result in the current author's opinion. the following are references concerning the chemical constituents as determined by analytical profiles (guo, 1985; xiao, 1983; . yu et al. (2007b) developed a method involving ''biospecific" extraction and hplc for potential immunological components in cs. the two active compounds were identified as guanosine and adenosine. li et al. (2001b,c) found that cultured cs mycelia have a much higher content of nucleosides than natural cs. guo et al. (1998) described an hplc method for quantitative determination of adenosine and deoxyadenosine. li et al. (1999) determined adenosine in fermented products of cordyceps by reversed-phase hplc. ergosterol in cs can be determined by hplc li et al., 2004) , and, of course, ergosterol is present in all fungi. when there are many questions as to what are the active components, a section on optimisation may seem premature. however, kim and yun (2005) investigated the optimal culture conditions for the production of exopolysaccharides (eps) and cordycepin during submerged mycelial culture of c. militaris and cs. this was not done in the paper hamburger (2007) comments upon. fermentations were performed in flasks and in 5-l stirredtank bioreactors. the concentrations of mycelial biomass, eps and cordycepin achieved in submerged culture of c. militaris were higher than those of cs. as the authors claim, comparative studies between the two fungi are not available and the paper was the first report on the optimum medium composition for submerged culture of cs. cordyceps nutans pat. is another entomopathogenitic ascomycete belonging to the family clavicipitaceae which is parasitic on hemipteran insects (sasaki et al., 2005) . very few investigations have been made with this fungus. in this research, optimum temperature and ph for mycelial growth was determined. however, it appeared that growth remained low and commercial exploitation perhaps limited. however, it would be interesting to include this species in any future taxonomic treatments of the genus. optimisation of culture conditions for mycelial growth and production of polysaccharides and cordycepin were described by park et al. (2001b park et al. ( , 2002 , xu et al. (2002) , kim et al. (2003b,c) , xiao et al. (2004) , mao and zhong (2004) and hsieh et al. (2005) , although cordycepin is usually produced synthetically at present. two cases of lead poisoning were reported (wu et al., 1996) . these two patients took cordyceps herbal medicine for treatment of underlying diseases. loss of appetite and anemic signs of lead poisoning were manifested in one patient with a high blood lead level, while the other patient was asymptomatic. the lead content in the cordyceps powder was found to be as high as 20,000 ppm. after cessation of intake in the asymptomatic patient, and cessation of intake and treatment with chelating agents in the symptomatic patient, the blood lead levels returned to normal range. this report raises concerns about lead poisoning from unusual herbal medicine in general. this present review is not intended to be a taxonomic paper, but is essentially a review of the papers that employ the name cordyceps more or less loosely, to describe the fungus used in medicinally related experiments. however, in a most impressive paper, sung et al. (2007) state that cordyceps comprise over 400 species in their modern phylogenetic classification of cordyceps and the clavicipitaceous fungi. cordyceps fr. host range is broad, ranging from 10 orders of arthropods to the truffle-like genus elaphomyces, although most species are restricted to a single host species or closely related host species. the main objectives of the study was to reassess the (a) morphological traits used currently, (b) taxonomic utility of the anamorphic forms and (3) classification in relation to phylogenetic relationships. it may be worth mentioning that pcrs may be subjected to inhibition, and nucleic acids may be affected by the medium in which the fungus was grown (see paterson, , 2008 . unfortunately, sung et al. (2007) do not provide details of how the fungi were grown for analysis and so it is difficult to conjecture. obviously, as discussed in this review, the fungus produces numerous bioactive compounds which may be inhibitors or mutagens and the effect of metabolite production on the dna preparations need to be determined or misleading results may be obtained. however, to continue, it is worth mentioning that c. militaris maintains its name in the study while c. sinensis is now classified as ophiocordyceps sinensis. the taxon was historically classified in the clavicipitaceae, based on cylindrical asci, thickened ascus apices and filiform ascospores, which often disarticulate into part-spores. the fungus was characterized by having a pathological ecology on elaphomyces and arthropods, with infrageneric classifications emphasizing ascospore morphology, host affiliation and arrangement of perithecia. the production of welldeveloped often stipitate stromata was typical. sung et al. re-classified on the basis of phylogenetic relationships between 162 taxa by employing five to seven genetic loci. three clavicipitaceous clades were determined which rejected the monophyly of cordyceps and clavicipitaceae and most diagnostic characters used in cordyceps were not supported as being phylogenetically informative. however, the most consistent characters with the phylogeny were pigmentation, morphology and morphology of stromata. cordycipitaceae was validated based on c. militaris, the type of cordyceps, which included most cordyceps species that possess bright, fleshy stromata. the new family ophiocordycipitaceae was proposed. the majority of species here produce stromata that often possess aperithecial apices and are darkly pigmented, tough to pliant. elaphocordyceps was proposed for a subclade of the ophiocordycipitaceae, which includes species of cordyceps that parasitize (a) the fungal genus elaphomyces and (b) arthropods. the family clavicipitaceae included the core clade of grass symbionts, and the entomopathogenic genus hypoc-rella and relatives. the new genus metacordyceps is proposed for cordyceps species that are closely related to the grass symbionts in the clavicipitaceae s. s. metacordyceps includes teleomorphs linked to metarhizium and other closely related anamorphs. lists of accepted names for species in cordyceps, elaphocordyceps, metacordyceps and ophiocordyceps are provided. obviously, this work needs to be consulted in future work on the fungus for medicinal properties as does stadler et al. (2003) . too often authors have used highly conditional statements such as; the preparation ''may" have ''possible" activity against, for example, cancer, which are meaningless. it is claimed that modern studies are demonstrating anti-oxidant, vascular, immune, and anti-inflammatory effects (meletis and barker, 2005) and the mechanisms by which these mushrooms work are being elucidated. however, the journal in which the paper is published is dedicated to complimentary and alternative medicines. this implies it is not mainstream scientific and so scientists may not give it as much weight in comparison to, for example, phytochemistry or the journal of natural products. nevertheless, the former reports could be considered as providing leads for more scientific research. in general, problems include too many chemically uncharacterised crude extracts, inadequate taxonomic vigour, and over extrapolation of in vitro data to imply therapeutic value. this needs to be avoided as it falsely raises hopes for cures for serious diseases. furthermore, there are no biochemical data on how the insect are converted into fungal components, or if the insect host per se has pharmacological properties. poor (i.e. inadequate or obsolete) biochemical procedures and assays can also because problems (see hamburger, 2007) . the biological material being used often is not well characterised and there are few indications of specimens being available for other workers to repeat the described work for example (i.e. no voucher specimens are available), with some notable exceptions. a rather limited range of solvents have been employed to extract the components and, for example, chloroform/methanol is particularly efficacious for fungal compounds (e.g. paterson and bridge, 1994) . there is very little on the use of non-polar solvents. paterson et al. (2004) , paterson (2006) and paterson (2008) have advocated a method which may have utility in standardising bioactive fungi. in this scheme, a ''common, readily identifiable" morphological character is determined and then the fungus is analyzed for particular metabolites. in this case the steps may be: 1. produces stroma on lepidopteron insects. 2. produces detectable concentrations of, for example, cordycepin. the analysis for other compounds would be desirable and some potential marker compounds are provided in table 3 . however, the phylogenic approach of sung et al. (2007) will set the standards for decades to come and will profoundly influence future publications in all fields relating to cordyceps. table 3 summary of markers currently used for quality control of cordyceps and associated activities (after li et al., 2006a) compound type pharmacological activities comments nucleosides anti-tumour activities; ca 2+ antagonist; the release of various neurotransmitters presynaptically and anticonvulsant activity; stimulate axon growth in vitro and in the adult central nerve system nucleosides, especially adenosine, are usually used as markers, and the profiles can be applied for authentication of cordyceps polysaccharides anti-oxidation, immunopotentiation, anti-tumour, and hypoglycemic activity; anti-inflammatory activity and suppress the humoral immunity in mice represents the most biological properties of cordyceps, and less used as marker for quality control. thus, it should be developed ergosterol and its analogs cytotoxic activity, anti-viral activity, and anti-arrhythmia effect; suppress the activated human mesangial cells and alleviate immunoglobulin a nephropathy (berger's disease) ergosterol can be used as marker for quality control mannitol diuretic, anti-tussive and anti-free radical activities it sometimes is used as marker for quality control peptides anti-tumour and immunopotentiation activities a potential marker for quality control cordycepin: selective growth inhibitor derived from liquid culture of cordyceps militaris against clostridium spp regulation of apoptosis and t cell activation by fas-specific mab a fermentation product of cordyceps sinensis increases whole-body insulin sensitivity in rats amelioration of aminoglycoside nephrotoxicity by cordyceps sinensis in old patients antitumor sterols from the mycelia of cordyceps sinensis comparison of balanol from verticillium balanoides and ophiocordin from cordyceps ophioglossoides multi-level complexity in the use of plant allelochemicals by aposematic insects selected herbals human exercise performance the traditional chinese medicine cordyceps sinensis and its effects on apoptotic homeostasis cordyceps sinensis extracts do not prevent fas-receptor and hydrogen peroxide-induced t-cell apoptosis fungal populations and species cordyceps sinensis animal, vegetable or both? cordyceps sinesis (berkeley) saccardo: structure of cordycepic acid platelet hemopoiesis and ultrastructure observations in mice treated with natural cordyceps sinensis and its cultured mycelia the effect of natural cordyceps sinensis and its cultured mycelia on murine immuno-organs and function of the mononuclear macrophage system effects of cordyceps sinensis on murine t lymphocyte subsets the effects of chinese herbs on improving survival and inhibiting anti-ds dna antibody production in lupus mice morphological and genetic characterization of a cultivated cordyceps sinensis fungus and its polysaccharide component possessing antioxidant property in h22 tumor-bearing mice recent advances in studies on traditional chinese anti-aging material medica nmr and ir studies on the characterization of cordycepin and 2 0 -deoxyadenosine. zhongguo kang sheng su za shi (chin cordyceps sinensis mycelium activates pka and pkc signal pathways to stimulate steroidogenesis in ma-10 mouse leydig tumor cells effect of cordyceps sinensis on the proliferation and differentiation of human leukemic u937 cells genetic diversity and taxonomic implication of cordyceps sinensis as revealed by rapd markers determination of the anamorph of cordyceps sinensis inferred from the analysis of the ribosomal dna internal transcribed spacers and 5.8s rdna effect of cordyceps sinensis on cellular immunity in rats with chronic renal insufficiency farinosones a-c, neurotrophic alkaloidal metabolites from the entomogenous deuteromycete paecilomyces farinosus novel tetramic acids and pyridone alkaloids, militarinones b, c, and d, from the insect pathogenic fungus paecilomyces militaris protein constituent contributes to the hypotensive and vasorelaxant activities of cordyceps sinensis cordyceps sinensis increases the expression of major histocompatibility complex class ii antigens on human hepatoma cell line ha22t/vgh cells cordycepin (3 0 -deoxyadenosine) inhibits human platelet aggregation in a cyclic ampand cyclic gmp-dependent manner antioxidant and memory enhancing effects of purple sweet potato anthocyanin and cordyceps mushroom extract improvement of insulin resistance and insulin secretion by water extracts of cordyceps militaris, phellinus linteus, and paecilomyces tenuipes in 90% pancreatectomized rats cordyceps sinensis-and rhodiola roseabased supplementation in male cyclists and its effect on muscle tissue oxygen saturation asian herbals: opportunities for marketing traditional chinese medicines in the west cordycepin, a metabolic product isolated from cultures of cordyceps militaris (linn.) link cordymax cs-4 improves steady-state bioenergy status in mouse liver mushrooms in medicine and culture in vitro evaluation of antioxidant activities of aqueous extracts from natural and cultured mycelia of cordyceps sinensis antitumor activity of cordyceps sinensis and cultured cordyceps mycelia rebuttal on comparison of protective effects between cultured cordyceps militaris and natural cordyceps sinensis against oxidative damage induction of heat shock proteins (hsps) by sodium arsenite in cultured astrocytes and reduction of hydrogen peroxide-induced cell death vasodilating effect of cultured cordyceps sinensis (berk) sacc. mycelia in anesthetized dogs control of apoptosis by p53 effect of cordyceps sinensis on inhibiting systemic lupus erythematosus in mrl 1pr/1pr mice a novel immunosuppressant, isp-i, of isaria sinclairii effect of cordyceps sinensis on the th1/ th2 cytokines in patients with condyloma acuminatum effects of cordyceps sinensis on t lymphocyte subsets and hepatofibrosis in patients with chronic hepatitis b effect of cordyceps sinensis on tlymphocyte subsets in chronic renal failure isolation and identification of 3 0 -amino-3 0 -deoxyadenosine from cordyceps militaris determination of adenosine and 3 0 -deoxyadenosine in cordyceps militaris (l.) link. by hplc bioactive pterphenyl derivatives from a cordyceps-colonizing isolate of gliocladium sp preliminary study of cordyceps barnesii -comparison of the chemical constituents of cordyceps barnesii and cordyceps sinensis comment on comparison of protective effects between cultured cordyceps militaris and natural cordyceps sinensis against oxidative damage evaluation of the anti-inflammation screening model of macrophages cell line by the proinflammatory mediators secretions medium optimization for polysaccharide production of cordyceps sinensis in vivo and in vitro stimulatory effects of cordyceps sinensis on testosterone production in mouse leydig cells regulatory mechanism of cordyceps sinensis mycelium on mouse leydig cell steroidogenesis effects of extracted cordyceps sinensis on steroidogenesis in ma-10 mouse leydig tumor cells upregulation of steroidogenic enzymes and ovarian 17b-estradiol in human granulosa-lutein cells by cordyceps sinensis mycelium effects of cordyceps sinensis on testosterone production in normal mouse leydig cells cordyceps sinensis and its fractions stimulate ma-10 mouse leydig tumor cell steroidogenesis in vivo stimulatory effect of cordyceps sinensis mycelium and its fractions on reproductive functions in male mouse comparison of protective effects between cultured cordyceps militaris and natural cordyceps sinensis against oxidative damage co-n reaction-a new serological activity index-on wegener's granulomatosis world university rankings. the times higher education supplement a xanthocillin-like alkaloid from the insect pathogenic fungus cordyceps brunnearubra bcc 1395 bioxanthracenes from the insect pathogenic fungus cordyceps pseudomilitaris bcc 1620. ii. structure elucidation es-242 derivatives and cycloheptapeptides from cordycepssp. strains bcc 16173 and bcc 16176 structures of cordypyridones a-d, antimalarial n-hydroxy-and nmethoxy-2-pyridones from the insect pathogenic fungus cordyceps nipponica bioxanthracenes from the insect pathogenic fungus cordyceps pseudomilitaris bcc 1620. i. taxonomy, fermentation, isolation and antimalarial activity the immuno-enhancing effect of chinese herbal medicine cordyceps sinensis on macrophage j774 mycelial extract of cordyceps ophioglossoides prevents neuronal cell death and ameliorates beta-amyloid peptide-induced memory deficits in rats a mushroom lectin from ascomycete cordyceps militaris effect of medicinal plant extracts on forced swimming capacity in mice immunomodulatory activities of herbsnsenses tm cordyceps -in vitro and in vivo studies identification of cordycepin, a metabolite of cordyceps militaris, as 3 0 -deoxyadenosine the ikk nf-kappa b system: a treasure trove for drug development occurrence of gal beta (1-3) galnac-ser/thr in the linkage region of polygalactosamine containing fungal glycoprotein from cordyceps ophioglossoides polysaccharides in fungi. xxxii. hypoglycemic activity and chemical properties of a polysaccharide from the cultural mycelium of cordyceps sinensis polysaccharides in fungi. xxv. biological activities of two galactomannans from the insect-body portion of chan hua (fungus: cordyceps cicadae) structural features and hypoglycemic activity of a polysaccharide (cs-f10) from the cultured mycelium of cordyceps sinensis polysaccharides in fungi. xxxvi. hypoglycemic activity of polysaccharide (cs-f30) from the cultural mycelium of cordyceps sinensis and its effect on glucose metabolism in mouse liver a comparative study on the production of exopolysaccharides between two entomopathogenic fungi cordyceps militaris and cordyceps sinensis in submerged mycelial cultures larvicidal activity against plutella xylostella of cordycepin from the fruiting body of cordyceps militaris methanol extract of cordyceps pruinosa inhibits in vitro and in vivo inflammatory mediators by suppressing nf-jb activation optimization of submerged culture process for the production of mycelial biomass and exo-polysaccharides by cordyceps militaris c738 production and characterization of exopolysaccharides from an enthomopathogenic fungus cordyceps militaris ng3 ophiocordin, an antifungal antibiotic of cordyceps ophioglossoides hypocholesterolemic effect of hot-water extract from mycelia of cordyceps sinensis antifatigue and antistress effect of the hot-water fraction from mycelia of cordyceps sinensis activation of macrophages and the intestinal immune system by an orally administered decoction from cultured mycelia of cordyceps sinensis reinventing taxonomy: a curmudgeon's view of 250 years of fungal taxonomy, the crises in biodiversity, and the pitfalls of the phylogenetic age cicadapeptins i and ii: new aib-containing peptides from the entomopathogenic fungus cordyceps heteropoda homocitrullylaminoadenosine, a nucleoside isolated from cordyceps militaris inhibition of nucleic acid methylation by cordycepin. in vivo synthesis of s-3-deoxyadenosylmethionine by wil2 human lymphoblasts abrogation of streptococcal pyrogenic exotoxin b-mediated suppression of phagocytosis in u937 cells by cordyceps sinensis mycelium via production of cytokines cordyceps sinensis mycelium protects mice from group a streptococcal infection differentiation of cordyceps sinensis by a pcr-single-stranded conformation polymorphism-based method and characterization of the fermented products in taiwan growth inhibitors against tumor cells in cordyceps sinensis other than corydcepin and polysaccharides cordyceps sinensis as an immunomodulatory agent regulation of bronchoalveolar lavage fluids cell function by the immunomodulatory agents from cordyceps sinensis activation and proliferation signals in primary human t lymphocytes inhibited by ergosterol peroxide isolated from cordyceps cicadae medicinal and nutraceutical genetic resources of mushrooms a yanginvigorating chinese herbal formula enhances mitochondrial functional ability and antioxidant capacity in various tissues of male and female rats experimental study on effect of cordyceps sinensis in ameliorating aminoglycoside induced nephrotoxicity determination of nucleosides in natural cordyceps sinensis and cultured cordyceps mycelia by capillary electrophoresis anti-oxidation activity of different types of natural cordyceps sinensis and cultured cordyceps mycelia the contents and their change of nucleosides from natural cordyceps sinensis and cultured cordyceps mycelia simultaneous determination of ergosterol, nucleosides and their bases from natural and cultured cordyceps by pressurised liquid extraction and high-performance liquid chromatography the fruiting body and its caterpillar host of cordyceps sinensis show close resemblance in main constituents and anti-oxidation activity quality control of cordyceps sinensis, a valued traditional chinese medicine hypoglycemic activity of polysaccharide, with antioxidation, isolated from cultured cordyceps mycelia a polysaccharide isolated from cordyceps sinensis, a traditional chinese medicine, protects pc12 cells against hydrogen peroxide-induced injury rp-hplc determination of adenosine in fermented cordyceps effect of cordyceps sinensis on erythropoiesis in mouse bone marrow determination of ergosterol in cordyceps sinensis and cordyceps black-bone chicken capsules by hplc antitumor activity of cordyceps militaris on human cancer cell line inhibition of activated human mesangial cell proliferation by the natural product of cordyceps sinensis (h1-1): an implication for treatment of iga mesangial nephropathy inhibitory effect of cordyceps on carcinogenesis of the forestomach in mice oral administration of cordyceps does not affect lymphocyte subsets in stz-induced diabetic rats effects of fermented cordyceps powder on pulmonary function in sensitized guinea pigs and airway inflammation in sensitized rats effects of cordyceps sinensis (cs) on in vitro natural killer cells immuno-pharmacologic activity of cordyceps sinensis (berk) sacc anticarcinogenic effect and hormonal effect of cordyceps militaris link chemical constituents of cordyceps militaris (l.) link effect of fuzheng huayu recipe in treating posthepatitic cirrhosis influence of cordyceps sinensis (berk.) sacc. and rat serum containing same medicine on il-1, ifn and tnf produced by rat kupffer cells protection against radiation-induced bone marrow and intestinal injuries by cordyceps sinensis, a chinese herbal medicine inhibitive effect of cordyceps sinensis on experimental hepatic fibrosis and its possible mechanism anti-oxidation of paecilomyces sinensis (s. pnov.) intragastrically administered chinese herbal medicine cordyceps alleviates fasting hyperglycemia in diabetic rats anti-hyperglycemic activity of natural and fermented cordyceps sinensis in rats with diabetes induced by nicotinamide and streptozotocin the anti-hyperglycemic activity of the fruiting body of cordyceps in diabetic rats induced by nicotinamide and streptozotocin study on effect of cordyceps sinensis and artemisinin in preventing recurrence of lupus nephritis effects of the mycelial extract of cultured cordyceps sinensis on in vivo hepatic energy metabolism and blood flow in dietary hypoferric anaemic mice effects of the mycelial extract of cultured cordyceps sinensis on in vivo hepatic energy metabolism in the mouse hyperproduction of cordycepin by twostage dissolved oxygen control in submerged cultivation of medicinal mushroom cordyceps militaris in bioreactors antiarrhythmic effects of cordyceps sinensis (berk.) sacc medicinal mushrooms: a selective overview combined effects of cordyceps sinensis and methotrexate on hematogenic lung metastasis in mice inhibitory effect of cordyceps sinensis on spontaneous liver metastasis of lewis lung carcinoma and b16 melanoma cells in syngeneic mice activation of in vivo kupffer cell function by oral administration of cordyceps sinensis in rats antifibrotic effect of extracellular biopolymer from submerged mycelial cultures of cordyceps militaris on liver fibrosis induced by bile duct ligation and scission in rats pharmacological actions of cordyceps, a prized folk medicine the nephroprotective effects of the herbal medicine preparation, wh30+, on the chemicalinduced acute and chronic renal failure in rats isolation of galactosaminoglycan moiety (co-n) from protein-bound polysaccharide of cordyceps ophioglossoides and its effects against murine tumors the correlation between molecular weight and antitumor activity of galactosaminoglycan (co-n) from cordyceps ophioglossoides antitumor activity of protein-bound polysaccharide from cordyceps ophioglossoides in mice problems in the use of herbal and natural substances, with a specific example concerning the cardiovascular system growth inhibition of u937 leukemia cells by aqueous extract of cordyceps militaris through induction of apoptosis optimization of submerged culture conditions for the mycelial growth and exobiopolymer production by cordyceps militaris effect of agitation intensity on the exobiopolymer production and mycelial morphology in cordyceps militaris the coronamycin producer: a case of mistaken identity? ganoderma -a therapeutic fungal biofactory ganoderma disease of oil palm -a white rot perspective necessary for integrated control internal amplification controls have not been employed in diagnostic fungal pcr hence potential false negative results fungal enzyme inhibitors as pharmaceuticals, toxins, and scourge of pcr biochemical techniques for filamentous fungi solutions to penicillium taxonomy crucial to mycotoxin research and health inhibitory effect of cordyceps on carcinogenesis of the forestomach in mice cordyceps sinensis mycelium extract induces human premyelocytic leukemia cell apoptosis through mitochondrion pathway a cyclopeptide from the insect pathogenic fungus cordycepssp. bcc 1788 10-membered macrolides from the insect pathogenic fungus cordyceps militaris bcc 2816 optimum temperature and ph for mycelial growth of cordyceps nutans pat. (ascomycetes) studies on anti-tumor activity of crude drugs. i. the effects of aqueous extracts of some crude drugs in shortterm screening test militarinone a, a neurotrophic pyridone alkaloid from paecilomyces militaris (+)-n-deoxymilitarinone a, a neuritogenic pyridone alkaloid from the insect pathogenic fungus paecilomyces farinosus down-regulation of apoptotic and inflammatory genes by cordyceps sinensis extract in rat kidney following ischemia/reperfusion treatment of hyperlipidemia with cultivated cordyceps -a double-blind, randomized placebo control trial trade of cordyceps sinensis from high altitudes of the indian himalaya: conservation and biotechnological priorities effect of cordyceps militaris on the damage of rats induced by n-hexane profiles of nucleosides and nitrogen bases in chinese medicinal fungus cordyceps sinensis and related species pharmacological activities of paecilomyces japonica, a new type cordyceps sp anti-tumour and immuno-stimulating activities of the fruiting bodies of paecilomyces japonica, a new type of cordyceps spp antioxidant and immunostimulating activities of the fruiting bodies of paecilomyces japonica, a new type of cordyceps sp pharmacological basis of 'yin-nourishing' and 'yang-invigorating' actions of cordyceps, a chinese tonifying herb chemotaxonomy of pochonia and other conidial fungi with verticillium like anamorphs clinical study on application of bailing capsule after renal transplantation cordyceps sinensis and cultured mycelia phylogenetic classification of cordyceps and the clavicipitaceous fungi effects of cordyceps sinensis, rhubarb and serum renotropin on tubular epithelial cell growth dmso modifies structural and functional properties of rpmi-8402 cells by promoting programmed cell death rapid and specific detection of hydroxyl radical using an ultraweak chemiluminescence analyzer and a low-level chemiluminescence emitter: application to hydroxyl radicalscavenging ability of aqueous extracts of food constituents free radical scavenging and apoptotic effects of cordyceps sinensis fractionated by supercritical carbon dioxide effects of a watersoluble extract of cordyceps sinensis on steroidogenesis and capsular morphology of lipid droplets in cultured rat adrenocortical cells pharmacological functions of chinese medicinal fungus cordyceps sinensis and related species an experimental study on anti-aging action of cordyceps extract entomogenous fungi that produce 2,6-pyridine dicarboxylic acid (dipicolinic acid) immunomodulatory functions of extracts from the chinese medicinal fungus cordyceps cicadae anti-inflammatory and related pharmacological activities of cultured mycelia and fruiting bodies of cordyceps militaris lead poisoning caused by contaminated cordyceps, a chinese herbal medicine: two case reports structural analysis of a neutral (1 ? 3),(1 ? 4)-b-d-glucan from the mycelia of cordyceps sinensis medicinal herbal extracts -renal friend or foe? part two: herbal extracts with potential renal benefits optimization of submerged culture requirements for the production of mycelial growth and exopolysaccharide by cordyceps jiangxiensis jxpj 0109 studies on chemical constituents of cordyceps sinensis i application of statistically based experimental designs for the optimization of exopolysaccharide production by cordyceps militaris ng3 effects of cordyceps sinensis on natural killer activity and colony formation of b16 melanoma structure and antitumor activity of an alkalisoluble polysaccharide from cordyceps ophioglossoides augmentation of various immune reactivities of tumor-bearing hosts with an extract of cordyceps sinensis inhibitory effects of water extracts from fruiting bodies of cultured cordyceps sinensis on raised serum lipid peroxide levels and aortic cholesterol deposition in atherosclerotic mice antioxidant activity of the extracts from fruiting bodies of cultured cordyceps sinensis cordyceps sinensis mycelium induces ma-10 mouse leydig tumor cell apoptosis by activating the caspase-8 pathway and suppressing the nf-jb pathway effects of exopolysaccharide fraction (epsf) from a cultivated cordyceps sinensis fungus on c-myc, c-fos, and vegf expression in b16 melanoma-bearing mice efficacy of a pure compound h1-a extracted from cordyceps sinensis on autoimmune disease of mrl lpr/lpr mice h1-a extracted from cordyceps sinensis suppresses the proliferation of human mesangial cells and promotes apoptosis, probably by inhibiting the tyrosine phosphorylation of bcl-2 and bcl-xl effects of cordyceps militaris extract on angiogenesis and tumor growth antitumor activity of an extract of cordyceps sinensis (berk.) sacc. against murine tumor cell lines antitumour activity of cordycepin in mice hypoglycemic effect of cordyceps militaris pharmacological activities of stromata of cordyceps scarabaecola isolation and biological properties of polysaccharide cps-1 from cultured cordyceps militaris isolation, purification and identification of polysaccharides from cultured cordyceps militaris structural characterization and antioxidant activity of a polysaccharide from the fruiting bodies of cultured cordyceps militaris. carbohydr macrophage biospecific extraction and high performance liquid chromatography for hypothesis of immunological active components in cordyceps sinensis simultaneous determination of free ergosterol and ergosteryl esters in cordyceps sinensis by hplc anti-diabetic effects of ccca, cmess, and cordycepin from cordyceps militaris and the immune responses in streptozotocin-induced diabetic mice prosecutable function of cordyceps sinensis extracts for hepatic mitochondrial oxidative injuries in diabetic mice induction of hl-60 apoptosis by ethyl acetate extract of cordyceps sinensis fungal mycelium activation of murine peritoneal macrophages by natural cordyceps sinensis and its cultured mycelia lewis lung cancer of mice treated with cordyceps sinensis and its artificial cultured mycelia effects of the exopolysaccharide fraction (epsf) from a cultivated cordyceps sinensis on immunocytes of h22 tumor bearing mice immunomodulatory and antitumour effects of an exopolysaccharide fraction from cultivated cordyceps sinensis (chinese caterpillar fungus) on tumourbearing mice dynamical influence of cordyceps sinensis on the activity of hepatic insulinase of experimental liver cirrhosis influence of cordyceps sinensis on pancreatic islet beta cells in rats with experimental liver fibrogenesis epicoccins a-d, pipolythiodioxopiperazines from a cordyceps-colonizing isolate of epicoccum nigrum clinical and experimental studies on elimination of oxygen free radical of jinshuibao capsule in treating senile deficiency syndrome and its deoxyribonucleic acid damage repairing effects cordyceps sinensis -i as an immunosuppressant in heterotopic heart allograft model in rats cordymax cs-4 improves glucose metabolism and increases insulin sensitivity in normal rats inhibitory effect of cordyceps sinensis and cordyceps militaris on human glomerular mesangial cell proliferation induced by native ldl investigation on distribution and habitat of blaps rynchopetera fairmaire (coleoptera: tenebrionidae) in yunnan cordyceps sinensis in protection of the kidney from cyclosporine a nephrotoxicity inhibitory effects of alcoholic extract of cordyceps sinensis on abdominal aortic thrombus formation in rabbits mechanisms and therapeutic effect of cordyceps sinensis (cs) on aminoglycoside induced acute renal failure (arf) in rats effect of jinshuibao capsule on the immunological function of 36 patients with advanced cancer short-term curative effect of cultured cordyceps sinensis mycelia in chronic hepatitis b modulating effects of extractum semen persicae and cultivated cordyceps hyphae on immuno-dysfunction of inpatients with posthepatitic cirrhosis the scientific rediscovery of a precious ancient chinese herbal regimen: cordyceps sinensis part ii the scientific rediscovery of an ancient chinese herbal medicine: cordyceps sinensis part i immunosuppressive effect of cultured cordyceps sinensis on cellular immune response acknowledgements r.r.m. paterson is funded by grant sfrh/bpd/ 34879/2007 from fundac ßão para a ciência e a tecnologia, portugal. professor nelson lima, universidade do minho is gratefully appreciated for his unstinting support, as are other colleagues therein. l.e. gilbert, university of texas, austin was generous for allowing the use of his images of infected insects (fig. 1c-f ). marc stadler, university of bayreuth, germany is thanked for discussions. key: cord-352668-qjlqsb2k authors: cabello, francisco; sánchez, froilán; farré, josep m.; montejo, angel l. title: consensus on recommendations for safe sexual activity during the covid-19 coronavirus pandemic date: 2020-07-20 journal: j clin med doi: 10.3390/jcm9072297 sha: doc_id: 352668 cord_uid: qjlqsb2k sexual activity offers numerous advantages for physical and mental health but maintains inherent risks in a pandemic situation, such as the current one caused by sars-cov-2. a group of experts from the spanish association of sexuality and mental health (aesexsame) has reached a consensus on recommendations to maintain lower-risk sexual activity, depending on one’s clinical and partner situations, based on the current knowledge of sars-cov-2. different situations are included in the recommendations: a sexual partner passing quarantine without any symptoms, a sexual partner that has not passed quarantine, a sexual partner with some suspicious symptoms of covid-19, a positive sexual partner with covid-19, a pregnant sexual partner, a health professional partner in contact with covid-19 patients, and people without a sexual partner. the main recommendations include returning to engaging in safe sex after quarantine is over (28 days based on the duration one can carry sars-cov-2, or 33 days for those who are >60 years old) and all parties are asymptomatic. in all other cases (for those under quarantine, those with some clinical symptoms, health professionals in contact with covid-19 patients, and during pregnancy), abstaining from coital/oral/anal sex, substituting it with masturbatory or virtual sexual activity to provide maximum protection from the contagion, and increasing the benefits inherent to sexual activity are recommended. for persons without a partner, not initiating sexual activity with a sporadic partner is strongly recommended. sexuality is one of the aspects of personality in which the degree of intimacy and privacy is great. asking patients about their sex life often arouses misgivings and feelings of shame and/or guilt [1] . however, scientific evidence shows that successful sexuality benefits males and females physically and emotionally to, having a favourable impact on their quality of life. there is evidence that sexual activity has advantages for humans, including increasing our longevity [2] [3] [4] and improving our immune system, among others [5, 6] . additionally, successful sexual activity increases psychic wellbeing by improving mood, even in depressed and high-anxiety patients [7, 8] , falling asleep [9] ; stress [10] ; relaxation [11] ; physical form and providing a younger body image [12] thereby contributing to the prevention of post-traumatic stress and anxiety disorders [13] . sexual experience regularises the menstrual cycle [14] , relieves dysmenorrhea and reduces the risk of endometriosis [15] . sexual dysfunctions can cause some interpersonal conflicts by deteriorating either self-esteem or partner relationships [16] . additionally, it may constitute an early sign of some organic pathology such as cardiovascular [17] , neurological or endocrine diseases. there is also some evidence that sexual inactivity correlates with an increased frequency of cancer, need for major surgery, worsening mental health and the increase of cognitive decline and cardiovascular disease risk factors such as diabetes, hypertension and hypercholesterolemia [18] . the effects of sars-cov-2 on human sexual and reproductive function, including whether the virus passes the blood-testis and ovary barriers and whether there is any effect on sexual hormone production, are still unknown [19] . additionally, some studies are currently seeking to identify similar impacts across the different populations impacted by hiv [20] . in the current sars-cov-2 pandemic situation, sexual activity during quarantine could be a relevant aid in reducing the onset of post-traumatic stress and anxiety disorders that were experienced in other previous pandemic confinements. in canada, during the outbreak of severe acute respiratory syndrome (sars) in 2003, a high level of acute stress was observed among health workers [21] . ebola virus confinement in africa also increased suicides [22] and gender-based violence [23] . during the australian equine fever quarantine, a high level of anxiety was observed in 34% of those confined compared to 12% in those not confined [24] . in china, some of the health workers quarantined during the sars epidemic-maintained symptoms of post-traumatic stress disorder three years later [25] . sexual satisfaction is a good predictor of global life satisfaction in young people and older adults [26] . in a large survey on sexual health in spain [27] , people were interviewed about their motivation for sexual intercourse, and the vast majority pointed out that the main reason was either the search for emotional intimacy or to satisfy the need to love and be loved. additionally, sexuality, as a basic aspect of mental health, is a current topic of interest for clinicians and researchers [28] . there is some literature indicating the potential benefits of increased sexual activity during periods of forced isolation indicating that those who maintain frequent in-person, but not remote, social and sexual connections have better mental health outcomes [29] . given the psychologically negative repercussions of previous quarantines and the preventive benefits of healthy sexuality, it is reasonable to maintain one's safe sexual frequency. however, sexual intercourse requires close physical contact, and sars-cov-2 is very easily transmitted with this level of closeness [30] . physical contact entails high viral exposure. when sharing a home with a covid-19-positive person, the virus has been detected in 63.2% of room air samples and 66.7% of corridor air samples [31] . other known coronaviruses do not appear to be sexually transmitted, but sars-cov-2 has been found in bodily fluids such as the saliva, mucus, and faeces of infected people, albeit slightly less in urine (6.9%). some recent studies have reported the virus to be present in the testicular seminal duct [32, 33] compromising the safety of sexual intercourse by persistence for at least 2 weeks postinfection in urine, faeces and nasopharynx secretions. considering that 80% of those infected have mild symptoms or are asymptomatic, it is advisable to take some precautions at least during quarantine. the use of condoms and noncoital behaviour that does not involve direct contact with semen is highly recommended [34, 35] . the virus was very recently found in the vaginal discharge of an infected 65-year-old female even while she was receiving oral lopinavir/ritonavir plus remdesevir. after two previous negative results, the vaginal swab tested positive via a real time reverse transcriptase-polymerase chain reaction on days 7 and 20 from symptom onset [36] . this new finding raises the possibility that sexual intercourse could be an additional direct vector of infection, adding to the recent evidence of a likely faecal-oral transmission vector [37] , or indirectly by exposure of the rectal mucosa to saliva [38] . additionally, patients can persistently test positive on rectal swabs even after negative results from nasopharyngeal testing [39] . thus sexual, transmission may be possible despite apparent clinical recovery. using real-time reverse transcription polymerase chain reaction to routinely test for sars-cov-2 in faeces was recently recommended [37] . patients' sexual habits should be routinely investigated in order to avoid direct sexual practices if infected with covid-19. physicians should always address these questions in epidemiologic surveys on transmission routes in order to determine effective strategies to control infection. information about changes in sexual habits in the isolated population and in those infected by the virus is scarce so far. an increase in both, sexual desire and the frequency of sexual intercourse during the current covid-19 pandemic, compared to the previous 6-12-month period, has recently been shown, although the quality of sex decreased significantly [40] . however, another recent study showed that during the covid-19 outbreak, the frequency of sexual activity in china decreased significantly in men and women, accompanied by a lowering of risky sexual behaviours [41] . the main objective is to avoid contagion by covid-19 and, at the same time, maintain, as far as possible, active sexuality, given the multiple advantages that healthy sexuality brings according to scientific evidence. due to the ease of contagion and the lack of information about the possible transmission of sars-cov-2, a group of experts from the spanish association for sexuality and mental health, covering the fields of sexology, psychiatry, psychology and medicine reached a consensus. the multidisciplinary panel included four experts in the fields of family medicine, sexology, epidemiology, psychology and psychiatry. a bibliographic search was performed in the medline, scopus, psycinfo and web of science databases without time limits. after searching the information sources, two reviewers independently preselected potentially relevant references using the keywords; sexual * and coronavirus or covid-19 or pandemic (645 refs). after preselection the search was refined, duplicates were removed, and 83 refs were found. after reading the complete articles, those that would ultimately form part of the review were selected (38) . based on the current knowledge of the scientific literature, and considering the absence of either clinical guidelines or recommendations in this regard, the authors have developed a consensus on some specific recommendations to maintain safe sexual activity and to prevent the transmission of covid-19. the authors carried out three preliminary drafts until a full consensus of the final text was reached. in order to avoid the risk of contagion, the main recommendation is that tongue kissing and oral-sex relationships should be avoided. as indicated by recent recommendations from the new york department of health, "you are your safest sexual partner" [42] . thus, during the pandemic, and until the end of quarantine, it is a good time to devote oneself to autoerotic growth, which means, improving sexual health, and therefore mood, by training to optimise sexual response. under confinement with a sexual partner (not always a household partner), including the full diversity of partner types (homo, hetero, bisexual, nonheteronormative couples with polyamory or those who maintain living apart), there are several possibilities we can recommend to improve safe sexual activities by avoiding the risk of contagion to the greatest extent. to clarify the concept of "safe quarantine", our recommendation includes avoiding contact with high-risk populations during quarantine and avoiding restarting sex when in contact with a confirmed or highly suspected case. we contemplate two main scenarios: (a) partners living in the same household and (b) partner/s not living in the same household/starting a new relationship or polyamory. a. partner/s living in the same household. a sexual partner after passing complete asymptomatic quarantine. a sexual partner during quarantine. a sexual partner with suspicious symptoms of covid-19. a sexual partner that is positive for covid-19 5. a pregnant sexual partner. a sexual partner in contact with covid-19 patients. b. partner/s not living in the same household/starting a new relationship or polyamory. current information indicates that the average incubation period for covid-19 is 5.1 days (95% ci 4.5-5.8 days) and that 97.5% of cases developed symptoms in 11.5 days (95% ci: 8.2-15.6 days). the incubation period before the onset of fever is 5.7 days, and 98% of those infected have a fever in the first 12.5 days. only 1% develop symptoms after 14 days; there is a small but real possibility of symptomatology at 28 days after infection [43] . the recommendation is that after 28 days of confinement without symptoms and without external contact, sexual intercourse can be carried out according to the usual habits of the couple, but while increasing hygiene before and after sexual activity. this would be a good time to enhance sexual creativity by increasing communication about one's preferences and desirable experiences, possibly by sharing fantasies and testing new scenarios, engaging in erotic readings, or viewing erotic films. before starting sexual activity, proper handwashing becomes essential to avoid virus transmission through fomites [44] and by touching the t-zones (mouth, nose and eyes) of the sexual partner's face [45] . it is also advisable to recommend strategies to avoid self-contact with one's own t-zones, as it happens without realisation at an average of 23 times per hour [46] . in this scenario, we must take into account that the severity of covid-19 depends on several factors, including viral load. it is possible that one member of the couple could be contaminated but asymptomatic as seen in a sample of 157 cases in singapore where 6.4% of presymptomatic transmission was identified [47] . in this case, sexual intercourse could be a major risk of contagion. the recommendation, before 28 days, is that one can practice safe sex using penetrative positions from behind, avoiding kissing, oral and anal sex, and by always using condoms. if a partner shows any suspicious symptoms, such as fever (which may be intermittent), cough, diarrhoea, severe and unexplained tiredness, sore throat, anosmia, hypogeusia, or other symptoms associated with covid-19, he or she may be in the incubation period or suffering from a mild form of the disease. the recommendation would be to avoid direct sexual activity. as a substitute, performing self-stimulation (masturbation while simultaneously keeping the safety distance of approximately 2 m), narrating erotic fantasies, sharing visualisations of erotic scenes, or using erotic board games might be suggested. if a sexual partner has tested positive for sars-cov-2, having sex is a possible source of contagion, so it is advisable to isolate in separate rooms. however, it is advisable to continue to practice some kind of sexual activity while avoiding physical contact, as recommended previously. one can, for example, use telematic applications to maintain erotic activities. it should be considered that people with active covid-19 infections may not want to engage in any sexual activity (even remote/virtual connections,) depending on the severity of their symptoms and personal preferences. once symptoms disappear, there is a high probability of contagion, as the virus persists in nasal secretions for an average of 9.5 days and in stool from 11 to 16 days (20 days if treated with corticosteroids) [48] . the duration for carrying sars-cov-2 in covid-19 (between 16-28 days) can increase up to 33 days in those over 60 years old, as well as in very severe cases [49] . waiting for this period of time before having coital sex and maintaining the recommended precautions for confined stable sex partners without passing quarantine are recommended. it is currently unknown whether pregnant individuals are more likely to get sick with covid-19, and there is still little information on the severity of the disease [50, 51] . other coronaviruses and viral respiratory infections, such as the flu, may carry a higher risk of developing complications or serious illnesses in pregnant women. therefore, since this is a population at risk, precautions should be increased [52] . pregnant individuals do not appear to be at greater risk than the general population, except for the presence of other associated factors, such as preeclampsia, hypertension, diabetes, and uterine atony. these individuals should follow the same preventative measures as those indicated for the general population. fetal transmission is unlikely as no viruses have been reported in either the umbilical cord, amniotic fluid, breast milk, or neonatal pharynx smears. however, in addition to the usual records, fetal ultrasounds and cardio recordings are recommended. in the case of maternal infection, there is a risk of postpartum transmission, for which screening tests will be needed [53, 54] . however, a recent joint review, including 37 infected pregnant women and 38 newborns in iran/china/usa aged 23-40 years-old, a placental transmission during the pregnancy was observed, while keeping normal amniotic fluid, vaginal discharge and milk secretion. no teratogenic effects were shown. however, the risk of infection with breast milk, cough or other vectors was high for 5-7 days after birth, so it is advisable to avoid breastfeeding if the mother is infected [55] . the recommendation is to use the same identified sexual strategies for stable sexual partners confined without passing quarantine, thus avoiding kissing, oral sex, and anal penetration, and using "a tergo" and posterior positions. the health workers, caregivers, and professionals in contact with infected people in hospitals, residential centres, or similar areas could spend a great deal of time exposed to the virus, possibly without adequate protection. thus, there is a high risk of accumulating a large viral load. the recommendation would be to follow the same strategy used for contaminated people (i.e., virtual sex). under no circumstances should sex be performed in vivo with a new partner unless there is the certainty that the partner has been immunised against the virus. for those who do not have a partner and for very erotophilic people, nonheteronormative couples with polyamory or those who maintain living apart, the recommendation is abstinence from sexual intercourse until the incubation time passes without symptoms after starting the coexistence. additionally, it might be worth using sexting or virtual sex. some swingers clubs organise erotic encounters through platforms in order to have virtual group sex. the measures that are generally taken to contain sars-cov-2 have undoubtedly decreased the professional activities of sex workers, and fewer casual sexual encounters in this context may affect individual risks for hiv infection and other stis [56] . in order to minimise the risk of infection when sporadic sexual intercourse occurs, condoms, dental dams or similar protection methods should be applied. in summary, we recommend maintaining an adequate level of eroticism and sexual activity, both in confinement and throughout the pandemic. this, along with other factors such as physical activity, social distancing or smoking cessation, will allow the minimisation of some part of its negative effects. however, it is necessary to meet the standards established by international organisations for the prevention of covid-19 [57] , given that sexual relations, regardless of sexual orientation-heterosexual, homosexual or bisexual-can facilitate its spread. a summary of the recommendations can be seen in table 1 , considering the previous different scenarios contemplated. our recommendations are comparable to those made by institutions such as new york citi health [53] , but so far, no specific recommendations have been published on safe sexual practices to avoid the transmission of the virus by other sources of trusted information such as the centers for disease control and prevention (cdc) or the world health organization. there is certainty that the vast majority of the global population will survive this pandemic, but associated stressors, such as uncertainty about the end of the pandemic, fear of contagion, and economic and social impairment, facilitate a weakening of the immune system [58, 59] . as there is evidence that sexuality promotes the immune system and physical and mental health, it is advisable to maintain an acceptable degree of sexual intercourse. there is some evidence that healthy sexual activity improves the immune system and serves as a more preventive factor against sars-cov-2. on the other hand, healthy, safe and frequent sexual activity might be attenuating (even if there is no evidence yet) the negative psychological effects associated with the infection. unfortunately, at this moment, there are no vaccines available for sars-cov-2 and we do not yet know how durable immunity is after an infection. currently, the epidemic is still spreading, and there are no effective means to prevent the infection. as most vaccines are under design and preparation, there is currently no possibility of having "certainty" around immunisation status [60] . additionally, sars-cov-2 may cause neurologic and psychiatric effects such as delirium in some patients in the acute stage and depression, anxiety and post-traumatic stress disorder in the long term [61] . therefore, the protective benefits of sexual activity and the maintenance of a suitable couple relationship could be beneficial to avoid the psychiatric and psychological deterioration that is secondary to the pandemic. on the other hand, it is very relevant not to stigmatise healthcare workers and consider them contaminated people. however, if the risk is high due to being in permanent contact with covid-19 patients, precautions should be taken to avoid infections due to the existence of frequent asymptomatic cases. in this sense, pregnant women should not be stigmatised either, although additional precautions are necessary to avoid possible consequences after infection in the mother and the fetus. undoubtedly, the pandemic has implied some big changes in the sexual behaviour of special groups such as sex workers, where it is difficult to issue recommendations because it is their only livelihood in low-income countries. the recommendation of sexual abstinence in this group is aimed at promoting changes to sex work due to increased potential exposure to infection and various health concerns, however, they could be very difficult to apply. innovative strategies launched by the leaders of sex workers and health workers, implementing new health protection guidelines and clinical spaces, are especially instructive [62] . additionally, other vulnerable populations such as men who have sex with men (msm), require special attention. a recent survey in the usa on sexual habits in msm during the pandemic showed that half had fewer sex partners and most had no change in condom access or use with increased difficulties in accessing hiv testing, prevention and treatment services. in addition to our recommendations to reduce the risk of sexual contact, it is necessary to apply other strategies such as telehealth and mailed testing and prevention supplies to avoid increased hiv incidence among msm during the covid-19 pandemic [63] . the risk of unwanted pregnancies is a consequence of the covid-19 pandemic [64] , because sexual and reproductive health services have remained closed during the pandemic. fortunately, in some countries, remote resources have allowed them to continue their preventive function by prescribing contraceptive methods, but unfortunately, in many others it has not been possible. we consider both, sexual and reproductive healthcare to be a priority, guaranteeing access to contraception as well as adequate information on sexual and reproductive health. some sexual intercourse-related scenarios may not be covered by these recommendations, and additionally, there is a lack of full information on virus behaviour and its impact on the sex life of infected patients and asymptomatic transmitters. however, keeping sex life healthy and safe is one of the biggest challenges for health prescribers and for the general population in this pandemic. furthermore, the peculiarities of sexual minorities during the pandemic are not yet known so these recommendations may not be widespread. there is not enough information about how the treatments received by infected patients affect their sex life or whether there are modifications to desire, arousal or orgasm compared to the previous stage. although many uncertainties still remain, the study of the sex life of this population could clear up scarce information about how the virus affects both the sexual and reproductive life. however, the benefits of maintaining a healthy sex life, harnessing its qualities and preventing contagion should be a priority in all sexual activity scenarios. these recommendations do not cover all minority sexual behaviours due to the great heterogeneity of human sexuality. however, they include most diversity of sexual activity regardless of orientation: heterosexual, homosexual or bisexual. our proposals for confinement include maintaining a security period of 28 days, before the couple can restart their regular sexual practices, since 1% of persons affected by covid-19 develop symptoms after an incubation period of 14 days. therefore, although we know that this could be a difficult recommendation for many couples to accept, we consider it relevant to safeguard security as much as possible. another relevant limitation is related to some still unknown facts, such as the duration of the immunity in people who have overcome the disease. this would be crucial to avoid reinfections when patients are supposedly immunised but do not respect the preventive measures implemented. further research is needed to obtain more precise data on the pathophysiology, prevention and treatment of covid-19, as well as to better understand the duration and level of immunity that overcoming the disease confers. with more scientific evidence, these are transcendental factors when recommending actions, that could avoid contagion through sexual activity. progress in the understanding of these aspects, through well-designed observational, case-control and experimental studies, will allow us to modify and enrich our current recommendations. staying at home and complying with strict confinement standards is the most active way to fight sars-cov-2. strengthening the immune system along with other factors such as increased positive interpersonal relationships and rewarding occupational activities, will help us fight the negative effects of the pandemic. this must be done without forgetting to reserve time for erotic activity that fosters creativity and communication. finally, confinement protects us from the risk of contagion, but at the same time, it can be an opportunity for the cultivation of eroticism through communication, fantasies, and exploration of a new self and heteroerotic scenarios, taking into account the health precautions established by international organisations against covid-19. predictors of the longevity difference: a 25-year follow-up five-year mortality in a 70-year-old urban population in relation to psychiatric diagnosis, personality, sexuality and early parental death retrospective cohort mortality study of roman catholic priests effects of sexual arousal on lymphocyte subset circulation and cytokine production in man oxytocin may have a therapeutical potential against cardiovascular disease. possible pharmaceutical and behavioral approaches sexual function and depressive symptoms among male north american medical students intimacy and belonging: the association between sexual 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offices: a cincinnati area research and improvement group (caring) network study face touching: a frequent habit that has implications for hand hygiene presymptomatic transmission of sars-cov-2-singapore persistence and clearance of viral rna in 2019 novel coronavirus disease rehabilitation patients duration for carrying sars-cov-2 in covid-19 patients information about coronavirus disease european centre for disease prevention and control. what about pregnant women? q & a on covid-19 advisory: novel coronavirus 2019 (covid-19) recomendaciones para el manejo del recién nacido en relación con la infección por sars-cov-2 (covid-19) an analysis of 38 pregnant women with covid 19, their newborns infants, and maternal-fetal transmission of sars-cov2: maternal coronavirus infections and pregnancy outcoms clinical features and outcomes of pregnant women suspected of coronavirus disease 2019 the impacts of isolation measures against sars-cov-2 infection on sexual health world health organization. coronavirus disease (covid-19) pandemic dna methylation: conducting the orchestra from exposure to phenotype? human social genomics progress and prospects on vaccine development against sars-cov-2 psychiatric and neuropsychiatric presentations associated with severe coronavirus infections: a systematic review and meta-analysis with comparison to the covid-19 pandemic the effects of covid-19 on the health and socio-economic security of sex workers in characterizing the impact of covid-19 on men who have sex with men across the united states in april contraception and reproductive planning during the covid-19 pandemic this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license key: cord-356062-7q5n4t97 authors: nan title: cumulative pharmacological activity index volumes 1-30 date: 2005-12-31 journal: studies in natural products chemistry doi: 10.1016/s1572-5995(05)80101-2 sha: doc_id: 356062 cord_uid: 7q5n4t97 publisher summary this chapter lists the important subjects on pharmacological activity that are discussed in the publication studies in natural products chemistry, volumes 1–30, such as abdominal constriction test, acanthoic acid, acetaminophen, parkinson's disease, photodynamic activity, prostaglandins, and oleanolic acid. the terms are mentioned along with the page numbers in which they are discussed in the publication. use of psycotria colorata in 30:205 19(4--+ 3)-abeo-8 c~, 13(s)-epoxylabda-4(18), 14-diene 29:102 activity in ebv bioassay system 29:102 19-nor-abieta-4( 18),8,11,13-tetraen-7one 29:100 activity in ebv assay system 29:100 abieta-8,11,13-trien-7-one 29:99 activity in ebv assay system 29:99 18-nor11, 7a, 15triol 29:99 activity in ebv assay system 29:99 11, 15, activity in ebv assay system 29:99 abieta-8,11,13-triene-7o~,l 5,18-triol 7acetate 29:99 activity in ebv assay system 29:99 abietic acid 29:99 activity in tpa assay system 29:99 activity in crg (+)-5-epi-acetomycin 10:447 antitumor activity of 10:447 2(x-acetoxy-14-hydroxy-15-iso-valeroyloxy-9-oxo-costunolide 29:89 activity in nfkb assay system 29:89 activity in tnf(x assay system 29:89 9cx-acetoxy-4 ~, 15-epoxymiller-1 ( 10)zenolide 29:89 activity in nfkb assay system 29:89 3~-acetoxy-813-isobutyryloxy-reynosin 29:87 activity in mam-2 assay system 29:87 activity in dif assay system 29:87 15-acetoxy-9 ~-hydroxy-8 [3-methacryloyloxy-14-oxo-acanthospermolide 29:89 activity in nfkb assay system 29:89 15-acetoxy-9cx-methacryloyloxy-8 ~hydroxy-14-oxo-acantho-spermolide 29:89 activity in nfkb assay system 29:89 3-acetoxycostunolide 29:89 activity in nfkb assay system 29:89 15-acetoxy-eremantholide b 29:89 activity in nfkb assay system 29:89 activity in tnf~ assay system 29:89 9~-acetoxy-miller-1 ( 10) 30:191, 192, 203 development of 30:192, 203 use of 30:191 analgesic effects 26:401, 403, 404, 406, 416, 418; 30:205, 208 5:512,747;10:78, 117;11:134;12:398;14:145;20:245, 712 ;21:21,108,109,190,207,213,214, 230,237,262,266,267,275,284,601, 615 ;23:41,126,164,235,258,355,468, 375,472,473,531,534,800;24:573, 856,857;26:226,1002;28:140,688; 30:328 11:130;12:192; 17:283 ;21:188,202,223,239,364,437; 23:649;24:953-954 21:186,192,197, 203,206,213,214,218,221,226, 227,233-235,223,238,240,389, 391,399,404,405,435,599-662; 22:626;23:3,4,271,341,344,348, 468,473,798,801354,368 ;26:227, 228,553,1098;28:4;66,473,475,686; 30:327,738,629 against candida albicans 30:327,629 from hypericum roeperanum 30:629 of (e)-8(17), 12-1abdadiene-15,16-dial 23:798 of (e)-8b, 17-epoxylabd-12-ene-15,16-deol 23:798 of (e)-8 [3,17-epoxylabol-12-ene-15,1619:511,748;21:132, 133,149,252,269,664,665 ;23:316, 533,534,687,704 ;24:742,743 ;30:226, 396,397 13:647;17:137,376;18:775;21:130, 134,153,152,312,591,594,690,616, 656,657;22:93,119,307,345,361; 23:158,297,512,602,832;25:43; 26:340,341,343,391,398,400,401, 403,404,406,415,418,482,556,558, 741,759,1035 ;27:660,858 ;28:200, 257,293 ;671,844;30:206,207,224, 225,292,320,689 21:674,744; 26:229,790,813,887,789,790,791, 800,805,807,810,811,821,828,830 -microbial activity 5:752;10:443; 15:327-339;18:776-778;21:153, 235,257,401,571,573,591,596,597, 599,606;22:626;23:94,153,180,233, 237,249,262,268,267,346,353,522; 24:64,69,206,330,331-334,402,403, 404,406,417,418,443,470,485,859, 1091,1092,1189;26:64,330,401,402, 1189;27:807;28:62,224,257,293; 28:698 22:308,321,345 ;23:395,534,535,742, 772,773,845 ;25:59;30:173,224,225, 289,320,321,524,561,743,745; 26:250,255,509,556,672,763,768, 887,1005,1006;28:4,16,17,63,179, 257,293 1:275,316-320-408; 17:17 ;21:137,405,420,435,436,638, 704,733;22:676;23:74,96,126,132, 139,395,445,522,696,721; 24:272-275 ;24:288,845,847,849; 25:43,430,431,438,450-453;26:56, 482,706;27:803;28:211,517,519,559, 560,566;30:3,28,29,55,56,58,59,64, 65,224,314,395,589,690,777,840 :461,563;10:608, 609,619,620; 17:146 ;21:132,148, 150,393,435,600,615,662,690,718; 22:307,361 ;23:233,268,233,346,395, 473,512,531,703;25:114;26:169,222, 224,226,344,452,741,759;27:482; 28:257,293 ;30:224,324-326,393,394, 395,398,401-405,407,410-412 132,148,162, 223,236,238,263,265,269,284,297, 366,388,390,410,419,421,431,571, 578,591,598,601,603,620,694 ;23:63, 93,95,108,111,129,126,107-152,153, 158,179,267,271,285,395-453, 455-485,491,497,642-643 ;739;24:25, 799,845 ;27:178,377,431,421,443, 693,778,801,924 ;24:353-376; 27:185-225,332,659;28:109,212,228, 229,340;29:743 ;30:4,26,172,175, 200,224,303,310,395,404,483,484, 485,495,496,497,499,562,588,603, 637,831,840,843, acaricidal enzymatic activity 24:995-998 tx-cembra-2,7,11-triene-4,6-diol 29:100 activity in ebv assay system 29:100 activity in pkc assay system 29:100 activity in skin-1 assay system 29:100 activity in odc assay system 29:100 ~-cembra-2,7,11-triene-4,6-diol 29:100 activity in ebv assay system 29:100 activity in skin-1 assay system 29:100 activity in odc assay system 29:100 of (-)-deoxypodophyllotoxin 30:589 of (-)-hemone 30:590 of (-)-nymphone 30:590 of (-)-yatein 30:590 of (+)-corytuberine 30:589 of (+)-epiaschantin 30:590 of (+)-epimagnolin 30:590 of (+)-epiyangambin 30:590 of (+)-hernovine 30:589 of (+)-laurotetanine 30:589 of (+)-magnoflorine 30:589 of (+)-malekulatine 30:590 of (+)-n-formyldehydroovigerine 30:589 of (+)-n-formylnornantenine 30:589 of (+)-n-formylovigerine 30:589 of (+)-n-hydroxyhemangerine 30:589 of (+)-n-methylhemangerine 30:590 of (+)-ovigerine 30:590 of (+)-ovihernangerine 30:590 of (+)-vateamine-2' [3-n134,136,150, 174,257,259,260,262,263,265,267, 269,270,271,273,274,284,311,364, 410,634,643,656,661,690,704,744; 23:96,97,187,218,238,249,250,253, 255,272,274,277,290,292,299,308, 317,701,274 ;24:294,352,740,867; 26:212-213,1185 as anti-fungal agents 24:406 2 [3,5-epoxy-5,10-dihydroxy-6c~ange lo y-lo xy-9 [3-is obutylo xygermacran-8ot, 12-olide 29:89 activity in inos assay system 29:89 activity in nfkb assay system 29:89 7 a, 8 c~-ep oxy-6 or-hydro xyabieta-9(11), 13-dien-12-one 29:99 activity in ebv assay system 29:99 9,10or-epoxy-9,10-seco-abieta4-o-phenyl-2-propionyl-neu5ac-cx2me 27:123 4-t-butyl-dimethyl-silyl ether 27:127 5-azido-5-deamino-neu5ac-c~2me 27:119 5-n-benzyloxycarbonyl-neu-cx2me 27:119 5-n-propionyl-neu-c~2me 27:119 7-deoxy-neu5 ac-c~2me 27:123,127 8-amino-8-deoxy-neu5 ac 27:121,122 8-azido-8-deoxy-neu5ac 27:121,122 8-tosyl-neu5acme ester 27:121,122 9-amino-9-deoxy-neu5 ac 27:121,122 9-amino-9-deoxy-neu5ac-c~2me 27:119 9-azido-9-deoxy-neu5 ac 27:121,22 9-azido-9-deoxy-neu5ac-c~2me 27:119 9-o-acetyl-neu5 ac-( ,590 activity of (-)-deoxypodophyllotoxin in 30:589 activity of (-)-hemone in 30:590 activity of (-)-nymphone in 30:590 activity of (-)-yatein in 30:590 activity of (+)-corytuberine in 30:589 activity of (+)-epiaschantin in 30:590 activity of (+)-epimagnolin in 30:590 activity of (+)-epiyangambin in 30:590 activity of (+)-hernovine in 30:589 activity of (+)-laurotetanine in 30:589 activity of (+)-magnoflorine in 30:589 activity of (+)-malekulatine in 30:590 activity of (+)-n-activity of hydroxyhernangerine in 30:589 activity of (+)-n-formylnornantenine in 30:589 activity of (+)-n-formyldehydroovigerine in 30:589 activity of (+)-n-formylovigerine in 30:589 activity of (+)-ovigerine in 30:590 activity of (+)-ovihernangerine in 30:590 activity of (+)-vateamine-2'13-noxide in 30:590 activity of 7-formyldehydrohernangerine in 30:589 activity of 7-formyldehydronornantenine in 30:589 activity of 7-formyldehydroovigerine in 30:589 activity of 7-hydroxy-6-methoxy12-hydroxy -6,7-seco-abieta-8,11,13trien-6,7-dial 29:99 activity in ebv assay system 29:99 7-hydroxy-6-methoxy-1-methyliso22:510,512,513,516,518,519, 521,522,525-529,531,534 achyranthes aspera l 9,459,503,753,754,311; 17:313,441 ;20:108-113,273,613; 24:215,228-232,503-509,739-798; 26:229,790,813,887;30:560,562,567, 570,590 chemo-differentiation therapy 30:498 of acute monocytic leukemia chemopreventive activity 30:591,597, 766 in mouse mammary organ culture model 30:591 in vitro 30:597 in vitro bioassays for 30:591 of chlorella vulgaris 30:766 ofisoquinoline alkaloids 30:597 of lignans 30:597 chemopreventive agent 26:219 genkwanin as chemopreventive efficacy 27:386 of limonene carcinogenesis 27:386 chemoprophylaxis 26:674 chemosensitizers 30:595 antimalarial drugs as 30:595 chemotaxonomic markers 26:1128 chemotherapeutic agent 30:5,330,742 atovaquone 30:330 for colon cancer 30:5 for multi-drug resistant cancers 30:5 for ovarian cancer 5 for taxol-resistant breast cancer chemotherapeutic intervention 30:397 targets for chemotherapy drug 27:436 antitumor activity of 27:436 chest pain 30:203 use of ginseng root in 30:203 childhood disintegrative disorder (cdd) gram-negative bacteria 30:693 maytenus species against gram-positive bacteria 23:68;30:629, 693 actamycin against 23:68 antimicrobial activity of 30:629 inhibitor maytenus species against grandiflorolic acid 29:100 activity in ebv bioassay system grandiflorolic acid angelate 29:100 activity in ebv bioassay system grandisin 26:230 trypanosomicidal activity of grandmal seizures granulocyte phagocytosis 26:47,55 ofjenisseensosides c 26:47,55 ofjenisseensosides d green tea 27:417,420 biological activity of 757 effect of general analogues on pgf2 na-induced contraction griseofulvin 24:934 as anti-fungal agents grob-type fragmentation 24:728,731 growth 30:61 of tumor cells 30:61 growth inhibition 17:142 growth inhibitor activity 7:407 guaiazulene 5:363,369 as an anti-inflammatory agent guidimacrin 27:831 antitumor mechanism 584 neurodegeneration 30:224 reperfusion injuries 30:224 respiratory disorders 30:224 role of free radicals in 30:224 human growth hormone human hek 293 cell line 30:781 biological response of human hl-60 leukemia cells 30:496 differentiation of 30:496 inhibition of 30:496 proliferation of human leukemia cells 18:269 human leukocyte elastase 16:727 inhibitor human leukocyte elastase (hle) 30:830,831,843 homologous sequences of 30:831 plasminogen activator (u-pa) 30:830 human lung carcinoma 23:290;30:5 discodermolide against human lung carcinoma) 30:691 phenolic triterpenes against 30:691 human medulloblastoma 23:290 human melanoma 23:255 human mesangial cell proliferation 30:308 in vitro human monoblastic leukemia cells 30:498 effect of hydroxyurea (hu) 30:498 growth inhibition of 30:498 human monoblastic leukemia u937 cells 30:498 growth inhibition of human neuroblastoma nbla-n-5 cells tamoxifen activity against 12:390 human neuroblastoma sh-sy-5y cells 12:390 human neutrophils 12:390 human neutropil protein kinase c 12:389 human onchocerciasis 12:9 ivermectin for human papilloma virus 30:394 pathogenesis of 30:394 cause of hepatocellular carcinoma human papilloma virus (hpv) 23:97 human papilloma virus type 11 30:406 microbicidal compound against human papilloma virus type 40 30:406 microbicidal compound against 30:406 human platelets 12:390 study of protein kinase c in 12:390 by staurosporine 12:390 human rotavirus (hrv) 30:406,412 cause of dehydrating gastroenteritis 30:406 member of 30:406 reoviridae type of human serotonin transporter gene (slc6a4) 30:376 regulation of neuronal activity human spermatozoa motility 21:675 human synovial pla2 25:697 inhibitor anti-glycemic effects 24:902-904 anti-hyperglycemic effects of -o-methyl-20-hydroxyecdysone activity in 29:28 pinnatasterone activity in 29:28 polypodine b 2-o-cinnamate activity in muscarinic achr antagonists 21:56 muscarinic antagonist 22:19 muscarinic receptor 21:95 muscarinic receptor antagonists 22:734 muscarinic-l,2-receptor 21:95 muscle pain 24:898 aconitine for relieving activation effects of 24:906 medicinal uses of 24:906 protein kinase c activation effects 24:906 muscular p-388 (murine lymphocytic leukemia) 30:588 activity of (-)-deoxypodophyllotoxin against 30:588 activity of (-)-yatein against p-388 lymphocytic leukemia cell 25:764 p388 mouse leukemia 12:390 staurosperine activity against p-388 murine leukemia cells 21:411 pachyman 5:288,317 antitumor activity of 5:317 pachyrrhizus erosus 24:779,822-826 anti-feeding activity of 24:825 pachyrrhizus palmatilobis 24:822 biological activity of 24:823 paclitaxel 240 (+)-acetoxypinoresinol dimethyl ether as 26:241 arctigenin as 26:241 arctigenin methyl ether as 26:241 chamigrenal as 26:244 cinnamophilin as 26:240 dehydroschisandrol a as 26:245 denudatin as 458 fptase inhibition by 24:458 paw oederma 30:207 inhibition of 30:207 2-pectenotoxin 19:580 cytoxic activity of 19:580 pectinasic pectolinaringenin 30:725,748 antispasmodic activity of 30:748 pedunculariside 29:84 activity in cox assay system 29:84 activity in epp assay system pelargonidin (anthocyanidin) 29:585 effects on lela 29:585 effects on penates sp. 28:713 as ~-glucosidase inhibitor 28:713 penicillium turbatum 11:194 antibiotic a 26771b by 11:194 penstemide 7:441 activity against p-388 lymphocytic leukemia penstemon rosseus 24:838 anti-fungal activity pentacyclic triterpenes 30:207 protein kinases inhibition by 564 in lipid autoxidation 3,4,6-p enta-o-gallo yl-~ -d-g luc o s e (galloyl ester) 29:589 effects on 229 biological activity of 28:229 8-prenyleriodictyol 28:229 biological activity of 28:229 prenylflavones 28:225 anti-human immunodeficiency virus (hiv) activity of 28:226 prenylfiavonoid 30:207 antinocicieptive effect of antitumor promoting activities of 29:720 as cytomegalovirus protease inhibitors 29:720 gastro-intestinal problems 29:720 use in hodgkins disease 29:720 use in infections 29:720 use in lupus 29:720 use in osteomyelitis 29:720 use in parkinson's disease 29:720 use in psoriasis 29:720 use in respiratory problems 29:720 use in skin ulcerations 29:720 use in syphilis 29:720 6-prenylnaringenin prevention by chitosan 27:436 of myelotoxicity 27:436 primary biliary cirrhosis 25:463 primary granulosa cells 25:269 apoptosis in 25:269 primary solid-tumor growth 30:64 effect of triterpenoids on 30:64 pristimarin 30:692 cytotoxic activity of prl1 & prl2 proproteins 29:592 effects on cysteine protease 851 probes 27:332 activity of 27:346 procurcumenol 29:90 activity in tnfct assay system procyanidin b 1 (dimeric flavan-3-ol) 29:580 effects on ace procyanidin b2 (dimeric flavan-3-ol) 29:580 effects on ace procyanidin b-5 3,3'-di-o-gallate 29:580 effects on ace procyanidin c2 (trimeric flavan-3-ol) 29:580 effects on ace 29:580 procyanidin polymer (flavan-3-ol polymer) 29:580 effects on ace prodrug monotherapy 21:157 natural anthracyclines for 21:157 prodrugs 21:157 of natural anthracyclines pro-inflammatory cytokines 25:461 pro-inflammatory substances 30:206 in chronic painful inflammatory diseases 30:206 proliferation 30:368,378 effect of serotonergic neurotransmission on 30:368 serotonin action on 30:378 prolysine 25:388 prophylactic effects pro-nociceptive prostaglandins 30:192 in inflammation pro-nociceptive transmitter 30:194 release inhibition of 30:194 prooxidant activities 30:745 in thiobarbituric acid assays 30:745 of chemiluminescence 30:745 of tert-butyl hydroperoxide 30:745 prooxidant property 30:524 of carotenoids 30:524 prophylactic drugs prostaglandin e2-dependent flavonoids cytoprotection effect pgh2) 25:595 prostaglandin inhibitors 30:192 clinical use of 30:192 use in rheumatism 30:192 use in osteoarthritis 30:192 use in headache 30:192 use in dental surgery anticancer clavulones 16:366 as antiviral compound 24:541-544 as pain mediator 30:192 in mast cells 30:192 nociceptive effect of prostate cancer prevention 30:525 role of lycopene protease inhibitor proteins from plants 29:596 effects on metallo protease inhibitors 24:487,488 567 cereal bifunctionals as 29:567 chymotrypsin as 29:568 destructive potential of 29:568 in alzheimer's disease 29:567 in angiogenesis 29:567 in cancer inflammatory disease 29:567 in protozoal infection 29:567 in viral infection 29:567 kunitz as 29:567 mustard family of 29:567 of metallocarboxypeptidase 29:567 ofserine protease 29:567 pepsin as 29:568 phytocystatins as 29:567 potato type 29:567 proteins as 29:567 serpin as 29:567 trypsin as 29:568 proteases 24:1005;29:567 enzymatic activity 24:1005 in apoptosis 29:567 in blood clotting 29:567 in cell division 29:567 in digestion 29:567 in extracellular matrix digestion 29:567 in inflammatory responses 29:567 protein kinase a (pka) 192 in regulation of ionotropic receptors protein kinase activity 28:677 ofxestoquinolide protein kinase c (pkc) activator 30:70 protein kinase c inhibition 24:573; 25:46,488 by xestocylamine 24:573 protein kinase inhibition 30:207 by pentacyclic triterpenes protein phosphatase inhibitors 27:874 protein phosphatases 25:707 inhibitor of 25:707 protein synthesis 30:407 inhibitor of 30:407 protein transduction domain (ptd) proteinaceous receptor 25:371 proteinase activity 21:150 protein-coupled receptor 27:821 g-proteine kinase c activity 21:638 proteins protein-tyrosine kinase activity 27:842 offlavonoid aglycones 27:842 of glycosides 27:842 ofkoelreuteria henryi protein-tyrosine kinase inhibitory activities proteolytic activity 30:841 proteolytic systemin inactivation protium kleinii 30:206 anti-inflammatory effect of 30:206 antinociceptive effect of 30:207 protocatechuic acid (3,4-dihydroxybenzoic acid) 29:589 effects on proton pump inhibitors (ppis) 25:612 proton-translocating nadh:q oxidoreductase 28:435 high-affinity inhibitors protozoocidal activity 30:329,741,742 against leishmania 30:329 against plasmodium 30:329 against tryponosoma 30:329 genus baccharis 30:741 in vitro 30:329 of neo-clerodane diterpenoids 30:742 ofquinone derivative 30:329 protozoocidal compounds 30:740 use of proxyelocytic leukaemia (hl-60) prunella vulgaris 30:401 antiviral activity of psammaplin a (bisprasin) 28:693 effects on bacillus subtilis psammaplysilla purpurea 28:693 antimicrobial activity of 28:693 as tyrosine kinase inhibitor pseudobersana mossambicensis 20:478 bioactive steroids from pseudoguaiane 11 a,13-dihydrohelenalin acetate 29:90 activity in cro assay system 627 against cytomegalo virus 30:627 against human immunodeficiency virus-1 30:627 against influenza virus 30:627 as virucidal agents 30:627 retroviral activity of 7:421 pseudolaric acid b 13:653 pseudomonas aeruginosa 30:739 antibacterial activity against 30:739 antifungal activity against pseudorabies virus 30:404 in vitro replication of 30:404 role ofheparin 30:404 psii inhibitors 26:368,371 psk in mitosis 25:377 psk-receptor 25:378 psk-a activity 25:378 psoriasis 30:484 use of lc~,25(oh)2d3 30:484 psychiatric disorders 30:369 anorexia 30:369 bipolar disorder 30:369 bulimia 30:369 effect of circadian activity on 30:369 obsessive compulsive disorder 30:369 panic disorder 30:369 schizophrenia 30:369 seasonal effective disorder 30:369 unipolar depression 30:369 psychodelic drugs 26:820 cocaine as 26:820 morphine as 26:820 semisynthetic lsd as 26:820 psychovegetative disorders 22:643,684 psycotria colorata 30:205 to relieve abdominal pain puberulin a 26:243,244 as paf-induced inhibitor pulegone 29:83 activity in am assay system 29:83 pulmericin 16:299 antifungal activity of 16:299 antileukemic activity of 16:299 cytotoxic activity 16:299 pulmonary vascular injury 30:70 role of serine protease in 30:70 role of thrombin pumiliotoxin alkaloids 27:238,239 alio-ptx 323 b alkaloid 27:249,250 biological activity of punta toro virus 30:411 treatment of 30:411 purifying blood 26:50 herniaria hirsuta in 26:50 purine receptors putative receptor proteins 25:398 putative satiety factor 24:910 effect of cholecystokinin 24:910 pyranocoumarin 27:429 biological activity pyranoid carbasugars 29:466 as cellular messengers 29:467 as insulin release mediators 29:467 biological activities of 29:466 effects on glycosidase enzyme 29:467 effects on glycosyltransferase enzyme 29:467 galactosyltrans ferase inhibition by pyridoacridine alkaloids 28:639 cytotoxic effects on kb cells 524 glycosidase inhibitors of 10:524 pyrrolomycin antibiotics 25:794 pytressin-induced coronary spasm antileukaemic activity of 4'-quercetagetin (6-hydroxy quercetin hexahydroxyflavone) (flavonol) 29:573 effects on 4'-pentahydroxyflavone) 29:578;30:208,749 analgesic effect of quercetin 3-o-c~-l-arabinopyranoside 28:64 anti-oxidant activity quercetin 3-o-c~-l-rhamnopyranoside 28:64,65 anti-oxidant activity of quercetin 3-o-[3-d-galactopyranoside 28:64 anti-oxidant activity o-galloyl)-glucoside 29:580 effects on ace quercetin-3-o-ot-l-rhamnopyranoside 28:64 anti-oxidant activity quercitrin (quercetin-3-rhamnoside) 29:581 effects on ace quillaia 26:55 of adjuvant activity 26:55 quinidine 25:347 quinine 25:344 290 antitumor activity of 10:117 inhibitor of dna quinoline drugs 25:348 quinoline drug family quinoline-based antimalarials 25:344 quinoline-ring antimalarial drugs 25:327 quinolines 25:327 quinolizidine derivatives 27:284,285 testing against mycobacterium tuberculosis 541-544 as antiviral quinone methides 30:694 antiplasmodial activity of 30:694 quinones rabidaea platyphylla 22:513 for epilepsy 22:513 rabies virus 30:409 inhibitor of 30:409 rabies virus infection 30:409 in chicken-embryo-related cells 30:409 rabies virus replication 30:409 in nerve fibers rachitic bone healing potencies 484 of vitamin d2 30:484 of vitamin d3 30:484 of vitamin d4 30:484 of vitamin d5 30:484 of vitamin d6 30:484 of vitamin d7 radical scavenging activity 23:362 of coumarin 23:335 radioligands 30:814 from brain membrane synaptosomes ranitidine 25:612,617 ranp-triggered signal transduction raphe nuclei 30:368 role in cognitive functions ras oncogenes 22:621 rat brain synaptosomes 30:807 p-affinity rat mammary carcinogenesis model 30:592 cancer chemopreventive activity rat serum vitamin d-binding protein (dbp) 30:494 binding assay for rebaudioside a 29:101 activity in tpa bioassay system tpa bioassay system 8-receptor 22:296 ~-receptor 22:296 8-receptor affinity 30:814 binding properties of 30:814 ~t-receptor affinity 30:814 binding properties of 30:814 of glycopeptide 30:814 8-receptor agonists k-receptor agonists 30:797,806 pharmacological activity of -receptor agonists 30:797 pharmacological activity of 30:797 8-receptor antagonists 30:797 pharmacological activity of k-receptor antagonists 30:797 pharmacological activity of 30:797 ~t-receptor antagonists 30:797 pharmacological activity of 30:797 receptor binding 27:377 receptor binding assay 30:810 in vitro 30:810 mouse vas deferens (mvd) activity in 30:810 of guinea-pig ileum (gpi) 30:810 receptor binding properties 30:815 of tyr-d-ala-phe-[[3-d-glc(oac)4]tyr-pro-ser-nh2 30:815 of tyr-d-ala-phe-asp-val-val-gly-nh2 (deltorphin c) 30:815 of oac)4]-gly-nh2: 30:815 of tyr-d-ala-phe-gly-tyr-pro-ser-nh2 (deltorphin c) 30:815 of tyr-d-ala-phe-gly-tyr-pro-thr([3-d-glc)-gly-nh2 30:815 of tyr-d-ala-phe-gly-tyr-pro-thr c )-val-vai-gly-nh2 receptor tyrosine kinase (rtk) 25:512 receptors 27:363;30:421 and cell-cell adhesion 30:421 and cell-cell communication 30:421 antigenic determinants of 30:421 for bacteria 30:421 ofchiral proteins 27:363 with enzymatic activity 27:824 without enzymatic recombinant prourokinase (pro-uk) 30:839 as fibrinolytic enzymes recombinant tissue-type plasminogen activator 30:839 as fibrinolytic enzymes 30:839 red wine 27:430 biological activity of 27:430 redox enzymes redox inhibitors 30:225 of 5-1ipoxygenase repandusic acid (hydrolysable tannin) 29:573 effects on hiv-1 protease 29:573 repellent properties 28:395 of amblyomma variegatum 28:395 reperfusion injuries 30:224 role of free radicals rescorcinolic lipids 30:165-167 effects on enzymatic activity 30:165-167 interaction with proteins reserpine 25:538 as immunosuppressive drug resistance-modifiers 30:595 antimalarial drugs as resistant plasmodium species 30:595 in chloroquine sensitivity resorcinolic lipids 30:119,158,160,162-164 as antifungal fluids 30:160 as growth reulators 30:162-163 as hair restoration-lotion 30:160 used in gingival infections respiratory ailments 24:847 respiratory depression 30:799 due to analgesic alkaloid 30:799 respiratory disorder 30:224 role of free radicals in 30:224 respiratory infection 30:408 respiratory syncytial virus 30:395 respiratory toxins 24:1002,1063 respiratory tract infections 26:50 herniaria hirsuta in 26:50 response decay mechanism 25:491 response modifiers resveratrol 27:430 biological activity of 27:430 resveratrol 28:582 effects in llc-bearing mice 28:582 effects on tumor 597 treatment of 30:597 use of hernandia moerenhoutiana in 30:597 use of hernandia nymphaeifolia 596 antimalarial activity of 30:595 antiplasmodial activity of 30:596 as platelet aggregation inhibitor 30:594 effect on antiplasmodial activity 30:596 retinal 29:111;30:520,521 activity in am bioassay system 29:111 in visual signal transduction 30:520 retinoic acid 29:111 activity in am, ebv, skin-1, odc bioassay systems 29:111 retinoic acid 30:493,498,521 in cell differentiation 30:521 in development 30:521 in growth regulation 30:521 retinoid retinol 29:111 activity in am retinol acetate 29:111 activity in am bioassay system retinol palmitate 29:111 activity in am bioassay system 29:111 retroviral enzymes 30:397 inhibitor of 408 causative agent of immunodeficiency syndrome 30:394 inhibitor of rett's disorder (rtt) 30:372,373,384 by mutations in mecp2 gene 30:373 genetic basis of 30:373 reutericyclin 28:127 as antibiotic reverse transcriptase 30:226,395,397 role in hiv replication cycle 30:226 role in viral replication rhazinilams 29:362 as microtubule poisons rheedia gardneriana 30:207 antinocicieptive effect of 30:207 rheumatism 26:50 herniaria hirsuta in 26:50 rheumatism 30:192,691 use of non-steroidal antiinflammatory drugs (nsaids) 30:192 use of prostaglandin inhibitors 30:192 rheumatoid arteriosclerosis 30:70 rheumatoid arthritis 21:152;22:310; 26:170,486;30:70,204,225 in treatment of cph82 26:170 in rats 30:204 reagent-induced 30:204 treatment of 30:225 use of kalopanax pictus rhoifolin (5, 4'-dihydroxy -7-rhamnosyl-glucosyl-flavone) 29:573 effects on hiv-1 protease 29:573 rhombenone 24:456 fptase inhibition by ricinoleic acid 30:193 analgesic action of 30:193 rickettsial pathogens 28:394 cowdria ruminantium as rifamycin-type macrolides 24:545,546 antiviral microbial-derived compound 24 rift valley fever infection 30:411 treatment of rimantidine 27:108 for treatment of influenza in infections 814 activity of deltorphin b in 30:807 of glycopeptide 30:814 rna virus 30:394 arenavirus type of 30:394 bunyavirus type of 30:394 coronavirus 30:394 influenza virus 30:394 measles virus 30:394 parainfluenza virus 30:394 picornavirus type of 30:394 rabies virus 30:394 reovirus type of 30:394 rotavirus type of rna-dependent rna polymerase activity 30:407 virion-associated rna-directed dna-polymerases 29:127 inhibition by sf-9 cell line 29:33 activity in mam-3assay system 29:100 antileukemic activity 8:18 sarcoptes mites 28:410 cause of human scabies 28:410 symptoms sarcoptes scabiei 28:409 cause of mange mites 28:409 cause of scabies sargasm horneri 30:400,405 anti-cmv activity of 30:405 polysaccharide (ps) from 30:400 sarkomycin 8:150 as antitumor agent 8:150 satratoxins 30:743 antiviral activity of 204 scavenging effects 23:443 of tannic acid 23:443 sch 207278 24:451 fptase inhibition by 24:451 schisandra 26:183 display platelet activating factor antagonist activity 26:183 effect on cardiovascular system 26:183 effect on heart rate 26:183 for treatment of hepatitis schisandrol a 26:245 as paf-induced inhibitor schistosomiasis (bilharzia) 7:405 schistosomicidal activity 1:545 schizonticidal drug 26:837 schizophrenia 101 activity in crg bioassay system 29:101 from scoparia dulcis scropolioside a 29:84 activity in tpa assay system 29:84 scrovalentinoside 29:84 activity in tpa assay system scutellaria baicalensis 30:55,56,69, 254,289 in allergric inflammatory disease 431 sdb 21:695 inhibitory effect of 21:695 sdc 21:695 inhibitory effect of 21:695 sdz-249-665 30:201 antinociceptive activity of 30:201 anti-hyperalgesic activity of 30:201 seasonal affective disorder 30:369 effect of circadian activity on 30:369 seaweeds 30:404 anti-cmv activity of activity in ebv assay system 29:100 1,2-secoemetine derivatives 6:485 amoebicidal activity of 6:485 secoiridoids 26:330 antimicrobial activity of 26:330 second messenger 25:516 secondary metabolites 28:3,432,617 acaricidal activity of 28:432 biological activity of 28:617 secondary metastatic tumor growth 30:64 effect of triterpenoids on 599 arnica as 22:559 artocarpus heterophyllus as basilicum polystachyon for 22:514 sedative activity 21:673 sedative in convulsions 22:518 crocus sativus l. for 22:518 sedative in epilepsy 22:535 withania somnifera l. as 22:535 g-selective agonist 30:807 dermorphin 30:807 8-selective antagonist tyr-tic-phe-nh2 selective antitumor activity 15:355 selective cytotoxicity 13:648 8-selective opioid agonist 30:817 deltorphin b 30:817 g-selective opioid peptide 30:802 8-selective opioid peptide of ici 19944 30:811 ofk opioids 30:811 8,g-selectivity 30:819 in vivo 30:819 of glyco analogues semilicoisoflavone b 28:229 biological activity of 28:229 semiochemicals semisynthetic lsd 26:820 as psychodelic drug 10-dihydro xy-7-methoxy-naphtho sendai virus infection sensory neurons 30:194 hyperpolarisation of 30:194 8er264 inhibitors serine 27:850 activitiy of serine 30:836 c~2-macroglobulin inhibition by serine protease inhibitor proteins 29:617 arrowhead pis api-a & api-b as cp-thionin as 29:617 effects on barley malt cysteine endoproteinases 29:617 effects on chymotrypsin 29:617 effects on subtilisin 29:618 effects on subtilisin eleusine double-headed try-~x-amylase inhibitor i-2 as 29:617 from brassica nigra 29:618 from brassica napus 29:618 from cassia fistula 29:617 from eleusine coracana 29:617 from hordeum vulgare 29:617 from phaseolus angularis from sagittaria sagittifolia 29:617 from sinapis arvensis 29:618 from vigna unguiculata 29:617 hordeum lipid transfer proteins as 840 blood clotting factors as 29:570 cathepsin g as 29:570 chymase as 29:570 chymotrypsin as 29:570 granzymes as 29:570 in angiogenesis 29:570 in blood clotting 29:570 in cytosolic proteolysis 29:570 in digestion 29:570 in inflammation 29:570 in proprotein processing 29:570 in tissue remodelling 29:570 kallikrein as 29:570 plasmin as 29:570 prolyl endopeptidases as 29:570 role in blood coagulation 30:70 role in platelet activation 30:70 role in pulmonary vascular injury serine proteases (subtilases) 25:388 cysteine proteinase inhibitor 25:370 poly phenol oxidase 25:370 serine proteinase inhibitor serine proteinase inhibitor i 25:370 as defense proteins serine-threonine-specific receptor protein kinases serotonergic innervations 30:377 autoradiographic imaging 30:377 in cerebral cortex 30:377 in neonatal rats by immunohistochemical techniques 30:377 physiological role of 377 serotonergic neurons 30:368,376 in raphe nuclei 30:376 role in 30:regulation of neurogenesis 627 as hyperforin inhibitor 30:627 as neurotransmitter 30:367 effect on synaptogenesis 30:378 in apoptosis 30:367 in cell proliferation 30:367 in presynaptic neuron 30:381 morphogenic properties of 30:367 neurochemical connection of 30:368 receptor activity of -ht) receptors 30:376,378, 382,383 in brain 30:383 in limbic brain regions 30:383 pharmacological aspects of serotonin (5-ht) re-uptake inhibitors 30:368 mechanism of serotonin (5-ht) synthesis 30:370,376, 377 in autistic children serotonin (5-ht) 1ar receptor antagonists 30:378 in posmatal treatment -ht)sa receptor 30:375 in brain development 30:375 in phenotypic behavioral irregularities 30:375 in purkinje cells 30:375 mrna expression of 30:375 serotonin action 30:378 on apoptosis 30:378 on maturation 30:378 on neuronal functioning 30:378 on proliferation serotonin agonists 25:531 anticomplementary activity of 25:46 role of cyclic amp-dependent protein kinase 25:46 delayed-type allergy suppressant activity of 25 serotonin synthesis inhibitor 30:378 parachlorophenylalanine as serum tc 27:420 biological activity of 27:420 serum transaminase 27:415,417,420 biological activity of 27:415 serum transaminase activity 25:469 of curcumia longa l serum triglyceride 27:404 biological activity sesquiterpene lactone 7:426 sesquiterpene quinones 5:429 antimicrobial activity of 5:429 cytotoxic activity of sesquiterpenoids drimane-type synthesis 29:127 avian myeloblastosis virus (amv) inhibition by 127 by jauch 29:127 sex pheromone sexual potency 28:4 ofbroussoflavonol g 28:4 sgot 30:292 activities of 30:292 sgpt 30:292 activities of 21:654 shikimic acid derivatives 29:478 antitumoral activity of 29:479 shinpterocarpin 28:229 biological activity of 28:229 sialic acids 27:103 biological function of 27:103 model for sialyltransferase activity 16:81 side effect 30:194,799 of analgesic alkaloid 30:799 of opioids sigmoidin a 28:229 biological activity sigmoidin b 28:229 biological activity of 28:229 signal reception 30:377 in autistic children 30:377 signal transduction mechanisms 25:518 signal transduction pathways signal transductors/activators of transcription (stats) 25:519 silandrin 26:255 as antihepatotoxic agent 26:255 silchristin 26:255 as antihepatotoxic agent 26:255 sildenafil 30:155 used for erectile dysfunction silymonin 26:255 as antihepatotoxic agent 26:255 simocyclinon 29:319 antibiotic activity of 29:319 cytostatic effects of 29:319 sindbis virus 17:135 sinomenine 25:472,476 hepatoprotective effect glycoside) 29:590 effects on pep 29:590 skin cancer 5:747 skin diseases 30:732 skin inflammation 30:323 anthrones used for 30:323 skk moth 1:704-706 juvenile hormone from slaframine 27:252 biological activity slaframine alkaloids 27:250,255 as muscarinic agonist 27:255 sleeping sickness smenoquinone 5:434,425 antimicrobial activity of smooth muscle relaxation 24:875-925 as biological action 24:875 of kampo medicines snake bite 30:691 treatment of 30:691 use of crossopetalum gaumeri 30:691 sobrerol 29:83 activity in mam-2 assay system 29:83 activity in gst assay system 29:83 activity in ras assay system 29:83 social phobia sodium salt of caffeic acid tetramer 24:742,743 anti-hiv activity of 24:742 soilborne fungi 21:181 bioactive metabolites from soilborne phytopathogens 21:182 biological control of 21:182 solandelactones 24:455 fptase inhibition by solanidane-induced teratogenicity 23:573 solid tumors neovasularization 25:593 somatostain 25:265 as a~ adenosine agonists somatostatin receptor 21:72;22:26; 25:530 type of g-protein-linked receptor 25:530 sonodione 30:566 from hernandia sonora 30:566 sores 30:616 tricyclic acylphloroglucinols sorivudine 24:474,486 as anti-viral agent 24 sorocein f 28:230 biological activity of 28:230 sos chromotest 22:623 soyabean saponins 25:222,223 hypocholesterdemic effects soyasaponins 27:398 anti-obesity action of 27:398 biological activity of 27:399 soybean trypsin inhibitor (sbti) spasmolytic activity 23:358 ;28:257,293; 30:264,561,748 of hernandia moerenhoutiana 30:561 ofhernandia voyronii 30:561 of imperatorin 23:350,358 of plant polyphenols 28:257,293 of thymus satureioides 30:264 on guinea pig ileum 30:748 on smooth muscles specionin 10:425 antifeedant activity of 10:425 spermicidal activity 26:53 of gypsophila paniculata sphingolipid receptor ca 2+ channels 25:535 sphingolipid receptors 25:534 sphinxolide 10:153;17:17 antitumor activity of 17:17 spider mite 1:702 hatching inhibitor spiroalkyl analogs 28:357 biological activity spirulina platensis 30:399,404,408 anti-influenza activity of 30:408 biological activity of 30:404 calcium spirulan from 30:399 polysaccharide (ps) from spleen/adipose tissue weight 30:56,57, 66 1203 effect of fucoidan on 30:56,57 effect of oleic acid on 30:65 spontaneous apoptosis 26:926 spontaneous metastasis squarroside a 26:31,50 immuno-modulatory effect of 26:31 from vaccaria segetalis squash family serine protease inhibitors 29:614 bd-ti-ii as 29:614 cmti-i as 29:614 cmti-iii as 29:614 cmti-iv as 29:615 cpgti-i as 29:615 cpti-ii as factor xiia, kallikrein, trypsin 29:615 effects on lysyl endopeptidase 29:614 effects on trypsin 29:614 effects on trypsin 29:615 effects on trypsin 29:616 effects on xa, xiia, kallikrein, plasmin, trypsin 29:614 elti-i as 29:615 from bryonia dioica 29:614 from citrullus vulgaris 29:614 from cucumis melo 29:614 from cucumis melo 29:614 from cucumis sativus 29:614 from cucurbita maxima 29:614 from cucurbita maxima 29:614 from cucurbita pepo 29:615 from cucurbita pepo 29:615 from ecballium elaterium 29:615 from echinocystis lobata 29:615 from lagenaria leucantha 29:615 from luffa acutangula 29:615 from luffa cylindrica cucurbitaceae) 29:616 from tricosanthes 29:616 hmti-i as 29:614 lati as 29:615 lati-ii as 29:615 lldti-i as 29:615 lldti-ii as 29:615 mcei-i as stachenone 29:101 activity in ebv bioassay system 29:101 standishinal 29:100 activity in ebv assay system 29:100 standishinal diacetate 29:100 activity in ebv assay system staphyllococcus aureus 30:693 minimal inhibitory concentration (mic) of staphyllococcus epidermidis 30:693 minimal inhibitory concentration (mic) of staphyllococcus saprophyticus 30:693 minimal inhibitory concentration (mic) of staphyllococcus warnieri 30:693 minimal inhibitory concentration (mic) of staphylococcus aureus 30:628,739 antibacterial activity against 30:739 antibacterial properties of 30:628 antifungal activity against starfish fertilisation inhibitor 28:712 callyspongin b as 28:712 stavudin 24:474,486,488 as anti-viral agent 24:474 steganes 29:360,399 cytotoxicity of 29:360,399 tubulin assembly inhibition by 29:360 antitubulin activity of 29:399,400 microtubules assembly inhibition by sterculia urens roxb. 30:405 antiviral activity of 30:405 steroid hormones 27:823 steroid saponins 7:426 teratogenic metabolites of 7:21-24 toxic cardiac active steroids sterol biosynthesis 25:303 inhibitor of 25:303 6a-sterol sulfate 28:702 cytotoxicity against sterol sulfates haplosamate a 28:703 as hiv-1 integrase inhibitor 28:703 sterols 25:43 antitumor activity of 25:43 antiinflammatory activity of 25:43 stevia stevia extract 27:307,310,314 for diabetics stevia leaves 27:315 immunological activity stevia plant 27:315 allergenic activity steviol 27:304,305,307,312 acute toxicity tests of 27:307 effect on fertility 27:312 mutagenicity tests with tpa bioassaysystem 29:101 activity in skin-1 bioassay system 29:101 acute toxicity tests of 27:307 allergenicity problems of 27:315 chronic toxicity studies of 27:306,307,308 effect on fertility 27:309,310 for phenylketonuria 27:315 mutagenicity tests for stigmasterol 30:208,505,570,719 analgesic effect of stilbene derivatives 27:405,409;28:579 biological activity of 27:405,409 in llc-bearing mice 28:579 tumor growth inhibition by 28:579 stimulatory 24:845 biological activity 24:845 stimulant agent 23:642 ofteucrium sp stimulus-response mechanisms 25:515 streptococci 29:535 pathogenicity of 29:535 serological groups streptokinase/streptodomase 25:271 streptolygidin 28:130 antibiotic activity of 28:130 as bacterial rna polymerase 28:inhibitor 130 as terminal dna transferase striga asiatica 30:162 infection with ofbioactive metabolites 21:251 of scopadulan-type diterpenoids structure activity relationship studies (sar) 30:195,494,800 of anandamide 30:196 of aspirin 30:195 ofopioid analogues 30:800 of vitamin d analogues 30:493 structure dereplication 29:658 bioactive natural product database in 29:670 of melanin inhibition strychnine 25:530 as immunosuppressive drug 25:530 strychnopentamine 26:1062 anticancer activity strychnos bisindole 26:1062 anticancer activity strychnos monoindole 26:1061 anticancer/protozoal subacute toxicity 27:307 from animals 27:307 of stevioside 588 effects on furin 29:588 sudhl-4-1ymphoma 21:138 sugar cane cystatins 29:593 effects on cysteine proteases 29:593 suicide inhibition 27:348 of 8'-hydroxylase 27:348 suicide inhibitors 9 sulfatobastadin 13 28:695 as endothelin a receptor inhibitor sulfide-containing pyrroloiminoquinones 28:685 as antileukaemic agents sulfur-containing cyclic peptides 28:678 biological activities of 28:678 cytotoxicity of sulphated polysaccharide (ps) 30:398, 400,405 anti-cmv activity of 30:405 anti-hiv activity of 30:398 antiviral activity against hiv 30:400 effect on viral replication 30:400 from marine sources 30:400 inhibitory effect of 30:398 mechanisms of action sulphated polysaccharide (ps) extracts 30:399 inhibitory activity of sulphonylurea drugs 25:534 sunflower cystatin phytocystatin 29:593 effects on cathepsin h ficin 29:593 effects on papain 29:593 sunflower multicystatin 29:593 effects on papain supercritical fluid extraction 21:576 superoxide dismutase superoxide dismutase activity 21:669 suppressing activity 30:308 on cells proliferation zizyphus saponin i as 27:41 zizyphus saponin ii sweroside 25:471,476 serum alt activity of 25 symbiotic marine microorganisms 23:185 bioactive metabolites 23:185 sympathetic ganglia 30:782 blockade of 30:782 sympathetic nerve activity 30:787 sympathomimetic amines 12:411 synapic potential mediation 28:318 by non-nmda receptors 28:318 synaptic actions 30:381 of serotonin synaptic dopamine transporters 25:539 synaptic glycine transporters 25:539 synaptic serotonin transporters 25:539 synaptogenesis 30:368,377 effect of serotonergic neurotransmission on 30:368 role in rodents 30:377 role of serotonin in 30:377 syndrome type-la 26:1130 adipose tissue distribution as 26:1130 cerebellar dysfunction as 26:1130 liver insufficiency as 26:1130 peripheral neuropathy as 26:1130 psychomotor retardation as synergistic activity 21:673 synergistic effect 21:608,611; 30:498,596 ofhervelines b 30:596 ofhervelines c 30:596 of retinoids 30:498 of vitamin d derivatives 30:498 synergistic interaction 21:698 of acyclovir(acv) 21:698 ofganciclovir (gcv) 21:698 with ganciclovir synergistic purgative actions 30:306 of rheinanthrone 30:306 of aloe-emodin-anthrone 30:306 synthetic pharmacological agents 30:224 antioxidant activity of 30:224 synthetic podolactones 28:484 allelopathic activity synthetic psychotropic agents 24:1093 syringaresinol 24:741 anti-platelet aggregation activity of systemic wound response protein 25:402 systemin activity 25:373 assay for ]-val-val-gly-nh2 30:815 receptor binding properties of receptor binding properties tyr-pro-ser-nh2 (deltorphin c) 30:815 receptor binding properties of -d-glc)-gly-nh2 30:815 receptor binding properties of oac)4]-gly-nh2 30:815 receptor binding properties of -d-glc)-tyr-pro-ser-nh2 30:815 receptor binding properties of -d-g lc )-v a 1-v al-gly-nh2 30:815 receptor binding properties of tyrosinase inhibitory activity 21:587 tyrosine kinase tyrosine-specific kinase 19:178 inhibitor of tyr-tic-nh2 30:809 activity in functional bioassay tyr-tic-phe-nh2 30:806 as 5 selective antagonist 30:806 u2 66 myeloma cell 25:273 ucn-01-ucn-02 12:386 antitumor activity of 12:395 protein kinase inhibitor ulapualides a 19:609 antifungal activity unsaturated carbapyranoses 29:475 as enzyme inhibitors 29:475 as herbicidal 29:475 biological properties of 29:475 unsaturated ketonucleosides 4:253 tumor inhibition by u-plasminogen activator (u-pa) 30:844 urdamycin a 11:134 antifungal activity of 11:134 antitumor activity ureterolithiasis-drug-therapy 27:382 urinary tract infections 26:50 herniaria hirsuta in 26:50 urine retention 30:194 as opioid's side effect 30:194 uroterpenol 29:83 activity in mam-2 assay system 29:83 activity in ras assay system ursane triterpene 29:585 effect on chy 29:585 ursolic acid 28:18,40;29:588 effects on hiv-1 protease 29:575 effects on lela 29:588 inhibition of hiv-1 protease dimerization by ursolic acid methyl ester (ursene triterpene) 29:575 effects on hiv-1 protease 29:575 usambarensine 26:1062 anticancer activity of 26:1060 uterine tumor 30:27 effect of pironetin derivatives in 30:27 uusambarine 26:1062 anticancer activity uvaol (triterpene) 29:588 effects on urs-12-ene-3,28-diol) (ursene triterpene) 29:575 effects on vaccaria segetalis 26:50 imunomodulatory effect of 50 vaccination 30:408 for respiratory infection as neuraminidase inhibitors 29:487 as c~-amylase inhibitor 29:486 c~-glucosidase inhibitors of 7:46;10:518 yeast a-glucosidase inhibitor of 10:518 valinuoctins 24:459 fptase inhibition by valiolamine 13:189,195 yeast c~-glucosidase inhibitor valiolamines 29:484 as glucosidase inhibitor 29:484 biological potential of 29:484 in clinical trials 29:484 in treatment of diabetes 29:484 valproic acid 22:507 vancomycin 25:791 vancoresmycin 28:150 activity against gram-positive bacteria vanilloid receptor agonist 30:202 olvanil as 30:202 capsaicin as 30:202 structure of vanilloid receptor antagonist 30:201, 202 capsazepine as 30 varicella-zoster virus 30:394 cause of varroajacobsoni 28:387 toxicity of varroa mites 28:383 vascular physiological action 30:55,69 of natural products vasodilating activity 21:379 vasodilator 23:358 scoparone as vasodilator effect 25:595 of acetylcholine vasodilatory activity 30:275 ofsatujera obovata vasoprotective agent 22:443 vasoprotective effects 28:302 of green tea vateamine-2' [3-n-oxide 30:567, 590,595 activity in human cancer cell line 30:589 activity in murine cancer cell line 30:589 as platelet aggregation inhibitor 30:594 cytotoxic effect of 30:589 veinotonic activities veraguensin 26:230 trypanosomicidal activity verapamil 25:534,673 as caz+-channel blocker 25:487 vermisporin 28:125 antimicrobial activity vernonia amygdalina 28:400 tick toxicity of 28:400 verrucarins 30:743 arenavirus junin 30:743 herpes simplex virus type ii (hsv-2) verrucosin 26:228 ofantiviral activity 26:228 vertebrate toxicity 21:98 vesicant activity vesicular glutamate transporters 25:538 vesicular monoamine transporter type 2 (vmat2) inhibitor vesicular stomatitis virus (vsv) 30:743,752 replication of 30:743 vesititol 28:224 anti-microbial activity of 28:224 vestitol 28:243 anti-helicobacter pylori activity of 28:243 veterinary medicine 28:383 for ectoparasites control 28:383 vetiver grass 28:399 for controlling ticks viagra (sildenafil) 25:541 vicolides 29:89 activity in ctn bioassay system 458 anticancer activity of 14:805 viral diseases 30:732 viral dna 30:226 integration of 12:332;21:98,193, 263,270,312,398,430,585,589,591, 594,643,659,670,673,675,690;23:59, 216,808;26:217;28:481 ;30 :629 against bone resorption 21:720, 721 against h+,k+-atpase 21:719 against staphyllococcus aureus 30:629 mechanism action of 30:225 of (-)-(8,8a-di-epi-swainsonine 12:325 of (-)-swainsonine 12:327 o f (+) cyasterone activity in 29:32 2-deoxy-20-hyroxyecdysone activity in 29:32 14-deoxymuristerone a activity in 29:32 2 [3,3 [3-dihydro xy-513-chole st-7en-6-one activity in 29:32 3 [3,14a-dihydroxy-5 [3-cholest-7en-6-one activity in 29:32 ecdysone activity in 29:32 313-hydro xy-5 [3-cho le st-6-one activity in 29:32 20-hydroxyecdysone activity in 29:32 inokosterone activity in 29:32 kc cell bioassay as 29:30 makisterone a activity in 29:32 muristerone a activity in 29:32 podecdysone a activity in 29:32 ponasterones activity in 29:32 213,313,513,14 a-tetrahydro x ycholest-7-en-6-one activity in 29:32 2[3,3 ~ ,25-tridihydroxy-513cholest-6-one activity in 29:32 viticosterone e activity in 29:32 insect control 21:611 insect juvenile hormone analogues 14:391-397 from thujone 14:391-397 insect pheromones 11: [415] [416] [417] via diisopropylethanediol esters 11:415-417 insect repellant 5:757 insecticidal activity 18:229,704;21:252, 254,262,266,267,269,270,271,278, 285,379,595,611;23:666;667,670, 677,678;24:25,799,845,866;26:231, 232,426,471,479,485;28:477; 30:153-154 activity of (-)-deoxypodo phyllotoxin in 30:589 activity of (-)-hernone in 30:590 activity of (-)-nymphone in 30:590 activity of (-)-yatein in 30:590 activity of (+)-corytuberine in 30:589 activity of (+)-epiaschantin in 30:590 activity of (+)-epimagnolin in 30:590 activity of (+)-epiyangambin in 30:590 activity of (+)-hernovine in 30:589 activity of (+)-laurotetanine in 30:589 activity of (+)-magnoflorine in 30:589 activity of (+)-malekulatine in 30:590 activity of (+)-n-hydroxyhemangerine in 30:589 activity of (+)-n-formylnornantenine in 30:589 activity of (+)-n-formyldehydroovigerine in 30:589 activity of (+)-n-formylovigerine in 30:589 activity of (+)-ovigerine in 30:590 activity of (+)-ovihernangerine in 30:590 activity of (+)-vateamine-2' [3-noxide in 30:590 activity of 7-formyldehydrohernangerine in 30:589 activity of 7-formyldehydronornantenine in 30:589 activity of 7-formyldehydroovigerine in 30:589 activity of 7-hydroxy-6-methoxy1:467,468;2:278,279,286, 289;6:108;7:103,110,121-123; 17:235,244 ;29:87 ;30:193,206 activity in ebv assay system 29:87 activity in skin 1 assay system 29:87 activity in crg assay system 29:87 activity in cro assay system 29:87 activity in aa assay system 29:87 activity in brk assay system 29:87 activity in cps assay system 29:87 activity in htm assay system 29:87 activity in paf assay system 26:3,4,10,13,15, 18,27,30,42,54,57;30:407 anti-inflammatory activity of 26:27 antiviral activity of 30:407 saponins 1:305; 402; 7:155, 156, 190, [426] [427] [428] [429] [430] [431] [432] 434, 435; 18:649 ajugasterone c activity in 29:28 amarasterone a activity in 29:28 amarasterone b activity in 29:28 cyasterone activity in 29:28 ponasterone a 2p-glucoside activity in 29:28 pterosterone activity in 29:28 rubrosterone activity in 29:28 sengosterone activity in 29:28 stachysterone c activity in 29:28 capitasterone activity in 29:28 sarcophytol a 29:100 activity in ebv assay system 29:100 activity in colon-2 assay system 29:100 activity in liver-2 assay system 29:100 activity in lung-1 assay system 29:100 activity in mam-3 assay system 29:100 activity in pancr assay system 29:100 activity in skin-2 assay system 29:100 sarcophytol b 8:18;29:100 activity in skin-2 assay system 29:100 use of platycodon grandiflorum key: cord-017504-rtg7fs82 authors: lim, t. k. title: punica granatum date: 2012-11-03 journal: edible medicinal and non-medicinal plants doi: 10.1007/978-94-007-5653-3_10 sha: doc_id: 17504 cord_uid: rtg7fs82 nan the pomegranate tree is native from the middle east to the himalayas in northern india. it has been cultivated and naturalised since ancient times throughout the mediterranean region of asia, caucasus, northern africa and europe. the fruit has manifold uses as it is today and was featured in egyptian mythology and art, in the old testament of the bible and in the babylonian talmud. from its native range, it was introduced to central and southern india and southeast asia. it was reported growing in indonesia in 1416. it was introduced into latin america and california by the spanish in 1796, it is now grown in california and arizona. it has been widely cultivated throughout india and drier parts of southeast asia and tropical africa. the most important growing regions are egypt, china, afghanistan, turkey, syria, pakistan, bangladesh, iran, iraq, india, myanmar and saudi arabia. there are some commercial orchards in israel on the coastal plain and in the jordan valley. pomegranate is primarily mild-temperate to subtropical and naturally adapted to regions with cool winters and hot summers, but can also be grown in warm tropical areas, such as in southern india, southeast asia and various islands in the caribbean. areas with mean annual temperature of 20-24°c is ideal. it suffers severe, irrecoverable injuries at temperatures below -11.0°c. the plant thrives in a semi-arid condition with mean annual rainfall of 500 to 1,000 mm and is extremely drought-tolerant. it does not fl ower and fruit well in very humid and wet climates. it is cultivated up to altitudes of 2,000 m as occur throughout the western range (baluchistan, n. & s. waziristan, nwfp, kurram, dir, chitral) in pakistan. the species is adaptable to a wide range of soil types including soils on which other fruit species will not grow. it thrives on calcareous soil, alkaline soil, gravelly soil and on deep, acidic loams. for commercial cultivation well-drained, heavy, light and medium soils are preferred although it can withstand seasonal waterlogging. irrigation is required to sustain high yields in drier areas. the fruit is relished fresh, out of hand by quartering the fruit and lifting out the rind to exposed the juice-laden arils around the seeds, both of which are eaten. the fruit is also consumed as juice which is the basis for lemonades or a beverage similar to wine. in the middle east, caucasus and india, pomegranate juice is a very popular beverage. for beverage purposes, the juice is usually sweetened. pomegranate juice is widely made into grenadine syrup for use in mixed drinks, cocktails and often processed into wine. in saudi arabia, the juice sacs may be frozen intact or the extracted juice may be concentrated and frozen, for future use. the juice can be processed into jellies by the addition of pectin and sugar. pomegranate is also used in food and as a spice condiment. fresh pomegranate arils are used in preparation of curd rice dadhojanam (telugu) in andhra pradesh in india. in northern india, the reduced juice is used for desserts and for marinating and tenderising meat due to its proteolytic enzymes. dried pomegranate arils are used in various cuisines such as trail mix, granola bars, or as toppings for ice-cream, yogurt and salads. dried whole arils are commonly sold in ethnic indian subcontinent markets. they impart a subtle, sweet-sour and tart fl avour popular in punjab and gujarat. dried pomegranate seeds, ' anardana ', has culinary importance as spice for vegetable and legume dishes in northern india and in pakistani cuisine. these dried seeds are used as an acidic condiment for chutney and curry preparation. the dried seeds can also be ground and used, which results in a deeper fl avoring in dishes and prevents the seeds from getting stuck in teeth. seeds of the wild pomegranate variety known as daru from the himalayas are renown as quality sources for this spice. in turkey, pomegranate seeds are also used in salads and sometimes as garnish for desserts such as güllaç . in greece and cyprus, pomegranate is used to make kolliva , a mixture of pomegranate seeds and sugar. pomegranate juice can also be processed into a concentrate, syrup and sauces for juice in food dishes and desserts. in iran, a traditional recipe fesenjan is made from a thick pomegranate sauce and ground walnuts used for duck and poultry or in a popular pomegranate soup ash-e nar . in azerbaijan, pomegranate sauce narsharab , made from pomegranate juice, is served with fi sh or tika kabab (grilled, roasted or stewed meat). in turkey, pomegranate sauce called nar ekşisi is used as a salad dressing, to marinate meat, or simply to drink straight. pomegranate syrup used in muhammara , a roasted red pepper, walnut, and garlic spread popular in syria and turkey. pomegranate is also popular in greek cuisine such as kollivozoum i, a creamy broth made from boiled wheat, pomegranates and raisins, legume salad with wheat and pomegranate, traditional middle eastern lamb kebabs with pomegranate glaze, pomegranate eggplant relish, and avocadopomegranate dip. pomegranate is also processed into a liqueur and fruit confectionery used as icecream toppings or mixed with yogurt and jam on toast. a deciduous, much-branched, small tree or shrub 1.5-6 m high with a smooth, dark grey bark (plate 1 ). branches are terete, opposite and branchlets usually ending in spines. leaves are opposite, glabrous, coriaceous, glossy green, entire, simple, oblong-lanceolate (plates 1 , 2 and 3 ) to obovate or elliptic, 19-35(−50) × 8-12 (−15) mm, subpetiolate, apex sub-actue to obtuse. flowers are large, showy, scarlet red or white, bisexual, to 4 cm across, solitary or clustered at the shoot apex (plates 2 and 3 ). calyx campanulate, reddish or purplish with six triangular, persistent lobes, petals 6, broadly obovate, wrinkled, alternating with the sepal lobes, stamens numerous, multiseriate, persistent, inserted on fl ower tube, ovary subglobose, inferior with three cells in two-series, style one thick, reddish, stigma simple slightly bilobed. fruit globose to subglobose, 6-8 cm in diameter, pale red to scarlet to purple or brownish,; the rind thick and coriaceous (plates 4 , 5 , 6 and 7 ). internally, the fruit is partitioned by thin leathery yellow septa into compartments fi lled with transparent sacs (arils) fi lled with tart, fl avourful, fl eshy, juicy, red, pink or whitish pulp (plates 7 and 8 ). in each sac, there is one white, pink or red, angular, soft or hard seed 10-13 mm long. food value of raw, pomegranate fruit (refuse 44% skin and membrane) per 100 g edible portion based on the california wonderful variety is as follows (usda 2012 ) : water 77.93 g, energy 83 kcal (346 kj), protein 1.67 g, total lipid (fat) 1.17 g, ash 0.53 g, carbohydrate 18.70 g; fi bre (total dietary) 4 g, total sugars 13.67 g, minerals -calcium 10 mg, iron 0.30 mg, magnesium 12 mg, phosphorus those of seeds, except potassium which was 49.2 ppm in the juice. the seed lipids had a refractive index of 1.518, melting point 13.0°c, iodine value 74.2, acid number 1.1, unsaponi fi able matter 0.7%, saponi fi cation value 188.9, ester value 187.8 and glycerol content 10.3%. the lipids contained 11 fatty acids, with caprylic (36.3%), the predominant acid, followed by stearic acid (22.5%); linoleic acid (10.3%) and oleic acid (5.1%). the saturated fatty acids of the seed lipids constituted 83.6% of the total fatty acids content. vitamin c content in 20 different turkish cultivars of pomegranate had a range of 312-1.050 mg/100 g, oil content a range of 2.41-3.73%, sterol content a range of 5.78-8.43%, anthocyanin content a range of 2,100-4,400 mg/l, potassium a range of 250-1,200 ppm, calcium a range of 35-326 ppm, magnesium a range of 176-427 ppm, iron a range of 21-46 ppm, sodium a range of 35-76 ppm, and phosphorus a range of 12-43 ppm (dumlu and gürkan 2007 ) . elfalleh et al. ( 2009 ) found total sugars of pomegranate juice comprised about 7 g/100 ml fructose and about 8 g/100 ml glucose, soluble proteins about 7 g/l, 9.46 mg/ 100 ml of phosphorus, and 271.94 mg/100 ml of potassium. the peel contained 9.43 and 210.86 mg/100 g of phosphorus and potassium respectively. the sodium contents were nearly 7 mg/100 ml in both peel and juice. nutrient composition of the juice for most components was comparable to the whole fruit. protein and fat values were higher in the whole fruit compared to the juice due to the seeds, which are 10% of the aril (juice sac) weight (thomas and gebhardt 2008 ) . pomegranate aril juice was reported to provide about 16% of an adult's daily vitamin c requirement per 100 ml serving, and to be a good source of vitamin b5 (pantothenic acid), potassium and antioxidant polyphenols. the tocopherol ( a -tocopherol, g -tocopherol, and d -tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry pomegranate seed (elfalleh et al. 2011a, b ) . a total of 18 compounds were found in pomegranate aroma pro fi les, including monoterpenes, aldehydes, alcohols, monoterpenoids and linear hydrocarbons . the most abundant compounds were trans -2-hexenal, 3-carene, a -terpinene and a -terpineol. the total concentration of volatiles ranged from 1.7 to 10.9 g/kg. overall consumer preference of pomegranate juices was associated with the presence of monoterpenes such as a -pinene, b -pinene, b -myrcene, limonene and g -terpinene. the presence of aldehydes such as hexanol, hexanal and cis -3-hexenol was correlated with poor overall consumer liking. high overall consumer liking was associated with intense and acceptable fresh pomegranate odour and fl avour (high scores of satisfaction degree), medium intensity of red colour and low sourness. pomegranate is a fruit rich in polyphenols that include fl avonoids, tannins and hydrolyzable tannins (gil et al. 2000 ; seeram et al. 2005a, b ) . pomegranate contain a complex mixture of gallotannins, ellagitannins, ellagic acid and anthocyanins (madrigal-carballo et al. 2009 ) . pomegranate juice was found to be rich in tannins, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins (gil et al. 2000 ) . the predominant organic acid in pomegranate was citric acid followed by malic acid (pande and akoh 2009 ) . the peel fraction had the highest total hydrolyzable tannins content (4,792.3-6,894.8 mg/100 g of fw). a total of 35 dimers of fl avanol-anthocyanin adducts were detected, consisting of mono-and disubstituted hexoside derivatives of the adducts between the fl avan-3-ols (epi)gallocatechin, (epi) catechin and (epi)afzelechin and the anthocyanidins delphinidin, cyanidin and pelargonidin in pomegranate juice (sentandreu et al. 2010 ) . anthocyanidins found in pomegranate fruit included: delphinidin, cyanidin, and pelargonidin (noda et al. 2002 ) . pomegranate fruit was reported to contain ellagic acid, gallagic acid, punicalins and punicalagins (reddy et al. 2007 ) ; ellagic acid, caffeic acid, luteolin and punicic acid (lansky et al. 2005a, b ) ; pelargonidin-3-galactose, cyanidin-3-glucose, gallic acid, quercetin, and myricetin (naz et al. 2007 ) ; gallic acid, methyl gallate, ellagic acid, (+) catechin, isoquerecitrin, d-mannitol, ursolic acid, oleanolic acid, b -sitosterol and daucosterol (rena et al. 2009 ) . pomegranate fruit was found to have a low level of indolamines (8-12 m g/g serotonin, 4-9 m g/g tryptamine, and 13-29 ng/100 g melatonin) (badria 2002 ) . gözlekçi et al. ( 2011 ) found that in all the turkish pomegranate cultivars the highest levels of total phenolic content were obtained from the peel extracts. the total phenolic content ranged from 1,775.4 to 3,547.8 mg gallic acid equivalent (gae)/l among the cultivars. however, the total phenolic content of pomegranate juice and seed extract ranged from 784.4 to 1,551.5 mg gae/l and 117.0-177.4 mg gae/l, respectively. four phenolic compounds were identi fi ed and quanti fi ed in pomegranate peel and pulp: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p -coumaric acids) (elfalleh et al. 2011a ) . ellagitannins isolated from pomegranate pericarp included: inhibitors punicalin, punicalagin, granatin b, gallagyldilactone, casuarinin, pedunculagin, tellimagrandin i, gallic acid, granatin a, corilagin and ellagic acid (satomi et al. 1993 ) . pomegranate fruit peel had been reported to be a rich source of hydrolyzable tannins called ellagitannins (ets); pomegranate ets were found to show potent antioxidant, antiatherosclerotic and anticancer activities (seeram et al. 2005b ) . the major fruit peel ets were punicalagin (80-85% w/w) and ellagic acid (ea; 1.3% w/w) and unquanti fi ed amounts of punicalin and ellagitannin-glycosides (hexoside, rhamnoside and pentoside). pomegrante fruit peel is currently an underutilized food by-product with potential to develop phytoceuticals with potential health bene fi ts or to develop products for use in the cosmetic and food biopreservative industries (seeram et al. 2005b ) . prodelphinidins and gallocatechins including gallocatechin, gallocatechin-(4-8)-catechin, gallocatechin-(4-8)-gallocatechin and catechin-(4-8)-gallocatechin were identi fi ed from pomegranate peels (plumb et al. 2002 ) . luteolin, luteolin 7-o -glucoside, kaempferol, kaempferol-3-o -glucoside, kaempferol-3-orhamnoglycoside and quercetin were found in the fruit peel (van elswijk et al. 2004 ) . of the ellagi-tannins isolated from pomegranate pericarp, seven namely punicalin, punicalagin, granatin b, gallagyldilactone, casuarinin, pedunculagin and tellimagrandin i were found to be active carbonic anhydrase inhibitors and four namely gallic acid, granatin a, corilagin and ellagic acid to be weakly active inhibitors. the type of inhibition by three and seven punicalagin and gallagyldilactone was found to be noncompetitive. a new antifungal peptide designated as pomegranin with a molecular mass of 11 kda, was isolated from fresh pomegranate peels (guo et al. 2009 ) . epicatechin, epigallocatechin 3-gallate, fl avan-3-ol, catechin were found in the fruit peel and juice (de pascual-teresa et al. 2000 ) . pomegranate fruit and juice were found to contain the following lignans: isolariciresinol, medioresinol, matairesinol, pinoresinol, secoisolariciresinol and syringaresinol (bonzanini et al. 2009 ). total lignin contents in the seeds was determined as 36.1 m g/g, in wood knots 17.8 m g/g, in fruit pulp 11.2 m g/g and in the endocarp.3.3 m g/g. syringaresinol was most abundant in the seed (23.5 m g/g), pinoresinol in knots (8.9 m g/g), pulp (7.4 m g/g) endocarp (3.3 m g/g) and juice (2.1 m g/g). lignans were also found in two concentrated juices and three pomegranate beverages at levels of 0.4-4.4 m g/g. in addition to the peel, mesocarp, and twigs, lignans were detected in two juices obtained from entire pomegranate fruits, four commercial juices, and three encapsulated pomegranate extracts (fischer et al. 2012 ) . isolariciresinol was the predominant lignan with contents of 5.0, 10.5, and 45.8 mg/kg dry matter in processed pomegranate mesocarp, peel, and twigs, respectively. six anthocyanin pigments identi fi ed as delphinidin 3-glucoside, delphinidin 3,5-diglucoside, cyanidin 3-glucoside, cyanidin 3,5-diglucoside, pelargonidin 3-glucoside and pelargonidin 3,5-diglucoside were found to be responsible for the red colour of pomegranate juice (cv 'mollar') (gil et al. 1995 ) . the fruit skin contained only the cyanidin and pelargonidin derivatives. generally, there was an increase in juice pigmentation with fruit ripening. the concentration of pigments in juice obtained from mature pomegranates ranged between 50 and 100 m g of anthocyanin per gram fresh weight of arils. six anthocyanin pigments delphinidin 3-glucoside and 3,5-diglucoside, cyanidin 3-glucoside and 3,5-diglucoside and pelargonidin 3-glucoside and 3,5-diglucoside were found to be responsible for the red color of pomegranate juice (hernández et al. 1999 ) . generally, juice pigmentation increased as the fruit ripened. in the early fruit-ripening stages, delphinidin 3,5-diglucoside was the major pigment, followed by cyanidin 3,5-diglucoside, while in the later stages, the monoglucoside derivatives cyanidin 3-glucoside and delphinidin 3-glucoside increased considerably. the pelargonidin derivatives were always present in small amounts. rp-hplc analysis of pomegranate arils' anthocyanins revealed mono-and diglucosylated delphinidins and cyanidins as the major anthocyanins and pelargonidins as minor components (borochov-neori et al. 2011 ) . anthocyanin accumulation changed inversely to the season's temperatures. cyanidins were generally more abundant but delphinidin accumulation was enhanced in cooler season. monoglucosylated anthocyanins prevailed at cooler temperatures and subsided during seasonal warming with a concomitant rise in diglucoside proportion. the major anthocyanins detected in the 15 iranian pomegranate varieties were as follows: delphinidin 3-glucoside (2.19-16.29 mg/l), delphinidin 3,5-diglucoside (2.36-63.07 mg/l), pelargonidin 3-glucoside (0.26-1.36 mg/l), pelargonidin 3,5-diglucoside (0.01-8.11 mg/l), cyanidin 3-glucoside (5.78-30.38 mg/l), and cyanidin 3,5-diglucoside (4.39-166.32 mg/l) (alighourchi et al. 2008 ) . the major anthocyanins in the juice of 6 iranian pomegranate cultivars were delphinidin 3,5-diglucoside (372-5,301 mg/l), cyanidin 3,5-diglucoside (242-2,361 mg/l), delphinidin 3-glucoside (49-1,042 mg/l) and pelargonidin 3,5-diglucoside (7-90 mg/l) (mousavinejad et al. 2009 ) . the cultivar, saveh black leather had the highest level of ellagic acid (160 mg/l). pomegranate juices obtained from six iranian pomegranate cultivars were found to have 15.77-19.56 total soluble solids content (brix), ph values of 3.06-3.74, titrable acidity concentration from 0.51 to 1.35 g/100 g, total sugars content from 16. to 22.76 g/100 g (faroogh), total antho-cyanins 7.93-27.73 mg/100 g, ascorbic acid 8.68-15.07 mg/100, total phenolics content 526.40-797.49 mg tannic acid/100 g, the total tannins level 18.77-38.21 mg tannic acid/100 g, condensed tannins from 12.14 mg to 12.57 catechin/100 g, antioxidant activity from 46.51 to 52.71% (zarei et al. 2010 ) . phenolics, fl avonoids, anthocyanins, and tannins of pomegranate juices, obtained from nine tunisian ecotypes were quanti fi ed by el kar et al. ( 2011 ) . phenolics ranged from 1,570 to 3,299 mg gallic acid equivalents/l and fl avonoids from 135 to 156 mg quercetin equivalent/l of juice. highest anthocyanin content was 156 mg cyanidin-3-glucoside equivalent/l and highest tannin content was 2,550 mg catechin equivalent/l of juice. tartaric and quinic acids were con fi rmed in pomegranate juice at concentrations of 1-5 and ~ 1 mg/l, respectively (ehling and cole 2011 ) . twenty-one volatile compounds were found in fresh pomegranate juices from nine spanish cultivars, including aldehydes, monoterpenes, and alcohols . the most abundant compounds were hexanal, limonene, trans -2-hexenal, and cis -3-hexenol. the presence of monoterpenes ( a -terpineol) was correlated with overall consumer preference of pomegranate juice while high aldehydes ( trans -2-hexenal) concentrations were correlated with poor overall consumer liking. 5-hydroxymethyl furfural was determined to be at a signi fi cant level in traditional sour concentrate of pomegranate juice (orak 2009 ) . pomegranate was known to contain estrogens (estradiol, estrone, and estriol) (mori-okamoto et al. 2004 ) . polysaccharide (psp001) was isolated from pomegranate rind (joseph et al. 2012 ) . pomegranate seed oil was found to have 8% saturated fatty acids, 10% monounsaturated, 10% diunsaturated and approximately 70% conjugated acid, most probably punicic acid (el-shaarawy and nahpetian 1983 ) . pomegranate seed was found to have high contents of a -tocopherol (161.2-170.1 mg/100 g) and g -tocopherol (80.2-92.8 mg/100 g). the seeds of punica granatum also contained ursolic acid and b -sitosterol along with a long straightchain hydrocarbon -nonacosene (ahmed et al. 1995 ) . presence of estrogens and glycosides were also detected. estrone, an estrogen, was identi fi ed in pomegranate seeds (heftmann et al. 1966 ) . cold pressed pomegranate seed oil was found to contain punicic acid (65.3%), palmitic acid (4.8%), stearic acid (2.3%), oleic acid (6.3%), linoleic acid (6.6%) and three unidenti fi ed peaks from which two (14.2%) were probably isomers of punicic acid (schubert et al. 1999 ) . pomegranate seed had an average lipid content of 19.2% with punicic acid as the predominant fatty acid (pande and akoh 2009 ) . pomegranate seed oil was found to be rich in 1-o -trans , cis , trans -9,11,13-octadecatrienoyl glycerol and also to have small amounts of 1-o -isopentyl-3-o -octadec-2-enoyl glycerol and the known cis -9-octadecenoic, octadecanoic and eicosanoic acids (fatope et al. 2002 ) . pomegranate seed oil (pgo) was reported to be rich in 70% cis (c)9, trans (t)11,c13-18:3 as conjugated linolenic acids (cla) (kohno et al. 2004 ) . a triglyceride, di-o -punicyl-o -octadeca-8 z ,11 z ,13 e -trienylglycerol, was isolated and characterized from the seeds of punica granatum from india and iran (yusuph and mann 1997 ) . four compound were isolated from pomegranate seeds namely . pomegranate seed oil from 21 pomegranate cultivars was found to have mainly unsaturated fatty acids (about 88%) (el kar et al. 2011 ) . the predominant fatty acid was linolenic acid (44.51-86.14%), followed by linoleic acid (3.57-13.92%), oleic acid (3.03-12.88%), palmitic acid (3.13-11.82%), stearic acid (1.68-15.64%), gadoleic acid (0.50-4.91%), lignoceric acid (<2.53%), arachidic acid (<1.70%) and myristic acid (<0.85%). pomegranate seed linolenic acid isomers, punicic acid and α-eleostearic acid were found in pomegranate seeds (tran et al. 2010 ) . a high yield (3.1-4.2%) of unsaponi fi able matter containing tocopherol, aliphatic alcohol (including policosanol), squalene, phytosterols and triterpene was obtained from pomegranate seed oil (caligiani et al. 2010 ) . the levels of squalene (up to 800 mg/kg), policosanol (118-185 mg/kg), b -sitosterol (up to 8,069 mg/kg) and cycloartenol (5,916-7,766 mg/kg) were found while b -and d -tocopherol were the most abundant vitamin e forms. the seed oil of p. granatum may be an interesting alimentary source of substances of nutraceutical value involved in the modulation of cholesterol metabolism. linolenic acid isomers like punicic acid and αeleostearic acid were reported from pomegranate seeds (tran et al. 2010 ) . qualitatively, the pomegranate fatty acid composition of 21 pomegranate cultivars (15 tunisian and 6 chinese) seed oil was identical comprising mainly unsaturated about 88% (elfalleh et al. 2011b ). the predominant fatty acid was linolenic acid (44.51-86.14%), followed by linoleic acid (3.57-13.92%), oleic acid (3.03-12.88%), palmitic acid (3.13-11.82%), stearic acid (1.68-15.64%), gadoleic acid (0.50-4.91%), lignoceric acid ( < 2.53%), arachidic acid ( < 1.70%) and myristic acid ( < 0.85%). ) isolated the following bioactive compounds from pomegranate seeds: coniferyl methy lellagic acid; 3,3 ¢ ,4 ¢ -tri-o -methylellagic acid; phenethyl rutinoside; icariside d1 and daucosterol. a new class iii chitinase (pomegranate seed chitinase) with a molecular weight of approximately 30 kda was isolated and puri fi ed from pomegranate seeds (yang et al. 2011 ) . this chitinase was found to naturally bind calcium ions with high capacity and low af fi nity, suggesting it to be a calcium storage protein. this enzyme was found to be widely distributed in the stroma of amyloplasts of the embryonic cells, suggesting that amyloplasts in seeds could serve as an alternative plastid for calcium storage. two new b -sitosterol esters elucidated as stigmast-5en-3 b -ol-3 b -dodecanoate ( b -sitosterol laurate) and stigmast-5-en-3 b -ol-3 b -tetradecanoate ( b -sitosterol myristate) along with the known com pounds n-tricosane, n-heptacosanyl n-hexanoate olean-5,12-dien-3 b -ol-28-oic acid and olean-12-en-3 bol-28-oic acid were isolated from pomegranate fl owers (bagri et al. 2009 b ) . a new polyphenol compound named pomegranatate, together with, ellagic acid, 3,3 ¢ ,4 ¢ -tri-o -methylellagic acid, ethyl brevifolincarboxylate, urolic and maslinic acids, and daucosterol were isolated from the ethanolic extract of the fl owers of punica granatum . maslinic acid exhibited antioxidant activity as evaluated by measurement of ldl susceptibility to oxidation. a taraxastane-type triterpene, punicanolic acid; two galloyl glucoses, 1,2,6-tri-o -galloyl b -d-glucopyranoside, 1,2-di-o -galloyl-4,6-o -(s)-hexahydroxydiphenoyl b -d-glucopyranoside; fl avones, luteolin; triterpnenes oleanolic acid, maslinic acid; and b -sitosterol were isolated from pomegranate fl owers (xie et al. 2008 ) . an alkaloid 2-(2-propenyl)-d 1-piperideine was isolated from pomegranate leaves (roberts et al. 1967 ) . pomegranate leaves were found to contain tannins granatin a, granatin b, corilagin, strictinin, 1,2,4,6-tetra-o -galloyl-b -d-glucose and 1,2,3,4,6 -penta-o -galloyl-b -d-glucose and an ellagitannin, punicafolin elucidated as 1, 2, 4-tri-o -galloyl-3, 6-(r)-hexahydroxydiphenoyl-b -dglucose (tanaka et al. 1985 (tanaka et al. , 1990 . pomegranate leaves were found to be rich in polyphenols: brevifolin carboxylic acid, brevifolin, corilagin, ellagic acid, 3,4,8,9,10-pentahydroxydibenzo[ b,d ] pyran-6-one, granatin-b and punicafolin (nawwar et al. 1994b ) ; n-(2 ¢ ,5 ¢ -dihydroxyphenyl) pyridinium chloride, as well as the known fl avone glycosides, apigenin 4 (nawwar et al. 1994a ) ; ellagitannin, punicafolin, tannins, granatins a and b, corilagin, strictinin, 1,2,4,6-tetra-o -galloyl-b -d-glucose and 1,2,3,4,6-penta-o -galloyl-b -d-glucose (tanaka et al. 1985 ) ; gallotannins, 1,2,4-tri-o -galloylb -glucopyranose and 1,3,4-tri-o -galloyl-b -glucopyranose together with the hitherto unknown ellagitannins, 1,4-di-o -galloyl-3,6-( r )-hexahydroxydiphenyl-b -glucopyranose and brevifolin carboxylic acid 10-monopotassium sulphate (hussein et al. 1997 ) . a hydroquinone pyridinium alkaloid in the form a mixture of a con jugated and a cross-conjugated heterocyclic mesomeric betaine was isolated from the leaves of punica granatum (schmidt et al. 2005 ) . balwani et al. ( 2011 ) isolated a novel compound, 2-methyl-pyran-4-one-3-o -b -d-glucopyranoside from pomegranate leaves. these alkaloid isopelletierine, methylisopelletierine, pelletierine, pseudopelletierine were isolated from pomegranate bark (chilton and partridge 1950 ; wibaut et al. 1954 ) and roots (chilton and partridge 1950 ) ; isopelletierine, methylisopelletierine and y pelleterine from bark (wibaut and hollstein 1957 ) ; and n-acetyl-sedridine from bark and root (neuhöfer 1990 ) . the bark is rich in punicotannic acid (about 22%) and also contains gallic acid, mannite and four alkaloids isopelletierine, methylisopelletierine, pelletierine, pseudopelletierine (grieve 1971 ) . the following alkaloids were isolated from pomegranate bark and roots: pelletierine, methylisopelletierine, pseudopelletierine and from roots norpseudopelletierine, sedridine, 2-(2 ¢ -hydroxypropyl) d 1-piperidine; 2-(2 ¢ -propenyl) d 1-piperidine, hygrine and norhygrine (neuhöfer et al. 1993 ) . tannins and related compound were isolated from pomegranate bark and included punicalin and punicalagin elucidated as to 4, 6-(s, s)-gallagyl-d-glucose (1) and 2,3-(s)hexahydroxy-diphenoyl-4,6-(s, s)-gallagyl-dglucose (2), respectively and a hydrolyzable tannin, 2-o -galloyl-4,6-(s, s)-gallagyl-d-glucose (tanaka et al. 1986a ) ; ellagitannins, punicacorteins a, b, c and d, punigluconin, casuariin and casuarinin (tanaka et al. 1986b ) . punicacor teins a, b, c and d were established as novel c-glycosideic ellagitannins, the former two possessing a unique tetraphenyl (gallagyl) ester group, and the latter two containing a galloyl group in place of the gallagyl group, while punigluconin was elucidated as 2,3-di-o -galloyl-4,6-(s)-hexahydroxydiphenoyl gluconic acid. a fl avonoid diglycoside, quercetin-3,4 ¢ -dimethyl ether-7-o -a -l-arabinofuranosyl (1 → 6)-b -dglucopyranoside, quercetin, pelargonidine-3,5diglucoside and ellagic acid were isolated from pomegranate bark (chauhan and chauhan 2001 ) . the heartwood of punica grantum was found to contain ellagitannins: diellagic acid rhamnosyl toumy and rauwald 2003 ) ; 3 ¢ -o -methyl-3,4methylenedioxyellagic acid, as well as eight known ellagitannins and gallotannins (el-toumy et al. 2001 ) . a new dimeric gallic acid glycoside named humarain was isolated from stem bark of punica granatum (tantray et al. 2009 ) . punica granatum is a unique medicinal plant with a long and extensive ethnomedicinal uses since ancient times. various parts of the plant viz. seed, aril, fruit juice, peel, leaf, fl ower, bark, and roots have been reported to contain bioactive phytochemicals with interesting medicinal values and pharmacological activities. the phytochemistry and pharmacological properties of pomegranate plant parts suggest a wide range of clinical applications for the treatment and prevention of ailments such as cancer as well as other diseases where chronic in fl ammation is believed to play an essential etiologic role . the synergistic action of the pomegranate constituents appears to be superior to that of single constituents. in the past two decade, numerous invitro, in-vivo and preclinical studies on the antioxidant, anticarcinogenic, and anti-in fl ammatory properties of pomegranate constituents have been published, focusing on treatment and prevention of cancer, cardiovascular disease, diabetes, dental conditions, erectile dysfunction, bacterial infections and antibiotic resistance, and ultraviolet radiation-induced skin damage (jurenka 2008 ) . other potential applications include infant brain ischemia, male infertility, alzheimer's disease, arthritis, and obesity. aqueous and ethyl acetate extracts of pomegranate arils, juice and peels exhibited good antioxidant activity (ricci et al. 2006 ) . pomegranate juice, peel, and seed oil antioxidants were con fi rmed by ferric reducing antioxidant power (frap) and oxygen radical absorbance capacity (orac) methods (elfalleh et al. 2011 ) . the highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol te/100 g for frap and orac assay, respectively. the tocopherol ( a -tocopherol, g -tocopherol, and d -tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry pomegranate seed. four phenolic compounds were identi fi ed and quanti fi ed in pomegranate peel and pulp: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p -coumaric acids). results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. in particular, the highest correlation was reported in peels. high correlations were also found between peel hydroxybenzoic acids and frap orac antioxidant capacities. identi fi ed tocopherols appeared to contribute in major part to the antioxidant activity of pomegranate seed oil. gil et al. ( 2000 ) found that the antioxidant activity of commercial pomegranate juices (18−20 teac) was three times higher than those of red wine and green tea (6−8 teac). commercial juices extracted from whole pomegranates showed higher antioxidant activity than in experimental juices obtained from the arils only (12−14 teac). further, they found that commercial juices contained the pomegranate abundant tannin punicalagin (1,500−1,900 mg/l) while only traces were detected in the experimental juice obtained from arils showing that pomegranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind. also, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins were found in the pomegranate juices. the results of studies by tzulker et al. ( 2007 ) showed that the antioxidant activity in pomegranate aril juice correlated signi fi cantly to the total polyphenol and anthocyanin contents. however, the homogenates prepared from the whole fruit exhibited an approximately 20-fold higher antioxidant activity than the level found in the aril juice. unlike the arils, the antioxidant level in the homogenates correlated signi fi cantly to the content of the four hydrolyzable tannins in which punicalagin was predominant, while no correlation was found to the level of anthocyanins. pomegranate juice was found to be a potent inhibitor of superoxide anion-mediated disappearance of nitric oxide . it was much more potent than concord grape juice, blueberry juice, red wine, ascorbic acid, and dl-α-tocopherol. as little as three μl of a six-fold dilution of pomegranate juice, in a reaction volume of 5,000 μ l, produced a marked antioxidant effect, whereas 300 μ l of undiluted blueberry juice or nearly 1,000 μ l of undiluted concord grape juice were required to produce similar effects. pomegranate juice and other antioxidant-containing products were found to augment the anti-proliferative action of nitric oxide (deta/no) on vascular smooth muscle cell (rat aorta) proliferation. and other antioxidant-containing products were found to augment the antiproliferative action of no on vascular smooth muscle cell (rat aorta) proliferation. pomegranate juice was much more effective than the other products tested and elicited no effects when tested alone in the absence of added no. pomegranate juice elicited no effects on enos protein expression or catalytic activity and did not enhance promoter activity in the enos gene. the observations indicated that pomegranate juice possessed potent antioxidant activity that resulted in marked protection of nitric oxide against oxidative destruction pande and akoh ( 2009 ) in their study found the highest antioxidant capacity to be in pomegranate leaves followed by peel, pulp, and seed. the tannin rich mixtures from pomegranate by-product exhibited ic 50 values against reactive oxygen species (ros) generation at 0.8-19 m g/ ml. the antioxidant capacity (orac) of pomegranate juice was 2,860 m mol te/100 g pomegranate juice which was comparable to blueberry and grape juice (thomas and gebhardt 2008 ) . oral administration of fl avonoid rich fractions from pomegranate fruits to rats at a dose of 10 mg/kg/day exhibited potential antiperoxidative activity (sudeesh and vijayalakshmi 2005 ) . malondialdehyde, hydroperoxides and conjugated dienes levels in the liver were signi fi cantly decreased antioxidative enzymes catalase, superoxide dismutase (sod), glutathione peroxidase and glutathione reductase were signi fi cantly elevated. glutathione content in the tissues were also increased. pomegranate fermented juice and cold pressed seed oil exhibited potent antioxidant activity almost equivalent to butylated hydroxyanisole (bha) and green tea ( thea sinensis ), but signi fi cantly higher than that of red wine ( vitis vitifera ) (schubert et al. 1999 ) . flavonoids extracted from cold pressed pomegranate seed oil exhibited 31-44% inhibition of sheep cyclooxygenase and 69-81% inhibition of soybean lipoxygenase. flavonoids extracted from pomegranate fermented juice displayed 21-30% inhibition of soybean lipoxygenase but showed no signi fi cant inhibition of sheep cyclooxygenase. total polyphenols in cold pressed pomegranate seed oil showed a concentration by weight of approximately 0.015%. fatty acid composition in cold pressed pomegranate seed oil showed punicic acid (65.3%) along with palmitic acid (4.8%), stearic acid (2.3%), oleic acid (6.3%), linoleic acid (6.6%) and three unidenti fi ed peaks from which two (14.2%) are probably isomers of punicic acid. acetone extract (70%) of pomegranate fruit displayed scavenging activity against hydroxyl (·oh) and superoxide (o2·-) radicals (noda et al. 2002 ) . its three major anthocyanindins, delphinidin, cyanidin, and pelargonidin, scavenged o2·in a dose-dependent fashion with id 50 values of 2.4, 22, and 456 m m, respectively but did not effectively scavenge nitric oxide. the anthocyanidins inhibited a fenton reagent ·oh generating system. further, the anthocyanidins inhibited hydrogen peroxide-induced lipid peroxidation in the rat brain homogenates with id 50 values 0.7, 3.5, and 85 m m, respectively for delphinidin, cyanidin, and pelargonidin (noda et al. 2002 ) . in another study, pomegranate elagitanninsellagic acid, gallagic acid, punicalins and punicalagins from pomegranate fruit showed ic 50 values of 1.1, 3.2, 2.3 and 1.4 m m, respectively, against reactive oxygen species (ros) generation and no toxicity up to 31.25 m g/ml against hl-60 cells (reddy et al. 2007 ) . the good antioxidant action of punicalagin a high molecular weight polyphenol isolated from pomegranate fruit pith and carpellary membrane was expressed not only through its scavenging reactions but also by its ability to form metal chelates (kulkarni et al. 2007 ) . binding of punicalagin with bovine serum albumin and metal ions such as iron and copper revealed different binding af fi nities, whereas its binding with dna was very weak and non-speci fi c. in-vitro cytotoxic studies against three cell lines, namely, vero (normal african green monkey kidney cell line), hep-2 (human larynx epithelial cancer cell line), and a-549 (human small cell lung carcinoma cell line) showed that punicalagin, was toxic only at higher concentration. studies found that pomegranate peel had the highest antioxidant activity among the peel, pulp and seed fractions of 28 kinds of fruits commonly consumed in china as determined by frap (ferric reducing antioxidant power) assay (guo et al. 2003 ) . in a subsequent study pomegranate peel extract was shown to have markedly higher antioxidant capacity than the pulp extract in scavenging or preventive capacity against superoxide anion, hydroxyl and peroxyl radicals as well as inhibiting cuso4-induced ldl oxidation. the contents of total phenolics, fl avonoids and proathocyanidins were also higher in peel extract than in pulp extract. the large amount of phenolics contained in peel extract may cause its strong antioxidant ability. the authors concluded that pomegranate peel extract appeared to have more potential as a health supplement rich in natural antioxidants than the pulp extract. separate studies showed pomegranate peel extracts to have both antioxidant and antimutagenic properties and may be exploited as biopreservatives in food applications and neutraceuticals (negi et al. 2003 ) . all the pomegranate peel extracts (ethyl acetate, acetone, methanol and water) exhibited marked antioxidant capacity, but the water extract was the lowest. the order of antioxidant capacity varied because of differential responses at four concentrations (25, 50, 75 and 100 m g/ml) in each solvent (negi et al. 2003 ) . studies in male rats showed that pomegranate fruit peel extract decreased lipid peroxidation in hepatic, cardiac, and renal tissues and serum glucose concentration (parmar and kar 2008 ) . pomegranate peels were found to contain potent antioxidant contents, as evidenced by free radical dpph scavenging value of 3.58 m g/ml and abts scavenging value of 7.364 mm trolox equivalent antioxidant capacity/100 g dry weight (elfalleh et al. 2009 ) . aqueous and alcoholic extracts of pomegranate rind showed good antioxidant effect with ic 50 ranging from 34.78 to 135.27/ml for aqueous and 40.03-105.93 m g/ml for alcoholic extracts (rajan et al. 2011 ) . phenolic compounds, tannins and fl avonoids were the major phytochemicals present in both the extracts. the aqueous and alcoholic extract yielded 122.33 and 176 mg/g gallic acid equivalent phenolic content, 135.33snf 81.33 mg/g quercetin equivalent fl avonoid and 81.66 and 114.23 mg/g tannic acid equivalent tannins respectively. plumb et al. ( 2002 ) found that the prodelphinidin dimers from pomegranate peels were potent antioxidants in the aqueous phase, being much more effective than the gallocatechin monomer in scavenging of the radical cation of 2,2-azinobis (3-ethyl-benzothiazoline-6-sulphonate, abts) relative to the water-soluble vitamin e analogue trolox c (expressed as trolox c equivalent antioxidant capacity, teac). in the lipid phase, only one of the dimers (gallocatechin-(4-8)-catechin) was signi fi cantly more effective than the monomer in the inhibition of lipid peroxidation of phosphatidylcholine vesicles. the water, methanol, acetone and ethyl acetate (etoac) extracts of pomegranate peel phenolics showed enhanced inhibitory effect on lard peroxidation as the phenolic concentrations increased . acetone extract exhibited the highest antiliperoxidant activity followed by water, methanol and etoac extracts. acetone extract at 0.1% (w/w) and water extract at 0.2% (w/w) exhibited an antiliperoxidant effect close to that of tea polyphenols (0.02%, w/w) and higher than that of bht (butylated hydroxytoluene) (0.02%, w/w). at 0.2% (w/w), acetone extract exerted a higher inhibitory activity on lard oxidation than that of tea polyphenols and bht. studies by guo et al. ( 2007 ) showed that showed that red pomegranate peel extract had the best effect on the scavenging ability of superoxide anion with lowest ic 50 value (4.01 m g/ml) among all pomegranate extracts (peel, juice, and seed of three varieties). the peel extract of white pomegranate had the best scavenging ability on hydrogen peroxide with the lowest ic 50 value (0.032 m g/ml) of the nine extracts. the seed extract of white pomegranate could scavenge hydroxide radical most effectively of the nine extracts (the ic 50 value 1.69 m g/ ml). the seed extract of white pomegranate (the ic 50 value was 3.67 m g/ml) was the most powerful on the dna damage-preventing effect of the extracts. the results of studies by xu et al. ( 2008 ) indicated that pomegranate peel extracts exerted protective effects on oxidative stress in mice loaded with restraint stress which may be attributed to its free radical scavenging activity and lipid peroxidation inhibitory effect. the extract decreased alanine aminotransferase and malondialdehyde levels and increased antioxidant capacity in the liver and glutathione levels in plasma as compared with restraint stress control mice. the methanol fraction of pomegranate peel showed highest antioxidant activity by all the four in vitro assays viz. dpph free radical scavenging, phosphomolybdenum, frap (fe(3+) reducing power) and cuprac (cupric ions (cu(2+)) reducing ability) comparable to ascorbic acid and butylated hydroxy toluene (bht) followed by activity in ethanol, acetone, and ethyl acetate fractions (zahin et al. 2010a ) . in cell free-systems, preparations from various parts of pomegranate displayed displayed good antioxidant capacity as assayed by 1,1-diphenyl-2-picrylhydrazyl (dpph), chemiluminescence luminol/xanthine/xanthine oxidase and lipoxygenase assays, with relative potency sequence of rind extract > pomegranate juice > aril juice (sestili et al. 2007 ) . however, only the rind extract was capable of preventing the deleterious effects -cytotoxicity, dna damage and depletion of non-protein sulphydrils (npsh) pool, caused by treatment of cells with hydroxide peroxide, tert-butylhydroperoxide or oxidized lipoproteins (ox-ldl) via a mechanism which was postulated to involve both direct scavenging of radical species and iron chelation. the results suggested that the aril juice the major and tasty part of pomegranate fruit, did not contain ellagic acid and punicalagin (i.e. the polyphenols highly represented in the rind which appeared to be responsible for the antioxidant capacity) in amounts suf fi cient to exert cytoprotection in oxidatively injured, living cells. based on these results, the authors advocated that development and evaluation of rinds-only based derivatives of pomegranate for antiatherogenic preventive purposes in humans should be encouraged. the antioxidant activity (percentage of inhibition of on peroxidation in linoleic acid system) of cpj (traditional sour concentrate of pomegranate juice) was determined to be higher (85.91%) than that of pj (pomegranate juice) (79.06%) (orak 2009 ). during the concentration process, the reducing sugars, glucose and fructose level of cpj showed an increase to 46.46, 23.89, and 22.53%, respectively. in cpj the amounts of sodium, iron, zinc, copper and lead were found lower than those of pj. in contrast, potassium and magnesium mineral contents increased during concentration. the total phenolics were also found to be 3,246 and 9,870 m g/ml in pj and cpj, respectively. the total anthocyanin content of pj was found to be 492.9 mg/l but it was not determined in cpj. 5-hydroxymethyl furfural was determined to be at a signi fi cant level in cpj as a result of the heat process. sezer et al. ( 2007 ) found that pomegranate and red wines decreased low-density lipoprotein (ldl) diene levels following a 30-min incubation period compared with controls. however, pure pomegranate wine demonstrated a greater antioxidant effect on diene level (110 m mol/mg of ldl protein) than pure red wine (124 m mol/mg of ldl protein). the phenol levels of pomegranate and red wines (4,850 mg/l gallic acid equivalents and 815 mg/l gallic acid equivalents, respectively) were in accordance with their total antioxidant activity (39.5 and 33.7%, respectively). four compound from pomegranate seeds namely coniferyl (4) displayed antioxidant activity, which was evaluated by measurement of low-density lipoprotein (ldl) susceptibility to oxidation and by in-vitro determination of malondialdehyde (mda) levels in the rat's brain . ethanolic extract of pomegranate fl owers was found to contain a large amount of polyphenols and to exhibit potent reducing ability, both indicative of potent antioxidant ability (kaur et al. 2006 ) . the extract showed 81.6% antioxidant activity in dpph model system. the fl ower extract was found to signi fi cantly scavenge superoxide (o 2− ) (by up to 53.3%), hydrogen peroxide (h2o2) (by up to 30%), hydroxyl radicals ( − oh) (by up to 37%) and nitric oxide (no) (by up to 74.5%). the extract also inhibited ( − oh) induced oxidation of lipids and proteins in vitro. these results indicated pomegranate fl ower extract to exert a signi fi cant antioxidant activity in-vitro. daily consumption of pomegranate juices was found to be potentially better than apple juice in improving antioxidant function in the elderly (guo et al. 2008 ) . as the plasma ascorbic acid, vitamin e, and reduced glutathione contents did not differ signi fi cantly between the apple and pomegranate groups in the study, the phenolics may be the functional components contained in pomegranate juice that accounted for the observations. recent in-vitro studies and preclinical animal studies have shown that pomegranate extracts selectively inhibit the growth of breast, prostate, colon and lung cancer cells (adhami et al. 2009 ) . an initial phase ii clinical trial of pomegranate juice in patients with prostate cancer reported signi fi cant prolongation of prostate speci fi c antigen doubling time. some of these researches are further elaborated herein. various parts of the pomegranate fruit e.g. seed oil, juice, fermented juice and peel extract, had been shown to exert suppressive effects on human breast cancer cells in-vitro and in this context, three estrogenic compounds, i.e. luteolin, quercetin and kaempferol, were detected in the fruit peel extract (van elswijk et al. 2004 ) . studies showed pomegranate fruit possessed chemopreventive and adjuvant therapeutic potential for human breast cancer (kim et al. 2002 ) . polyphenols from fermented pomegranate juice, pericarp, and oil inhibited aromatase activity by 60-80% indicating its ability to effect a blockade of endogenous active estrogen biosynthesis. fermented juice and pericarp polyphenols, and whole seed oil, inhibited 17-b -hydroxysteroid dehydrogenase type 1 from 34 to 79%, at concentrations ranging from 100 to 1,000 m g/ml in the sequence seed oil > > fermented juice polyphenols > pericarp polyphenols. lyophilized fresh pomegranate juice elicited a 55% inhibition of the estrogenic activity of 17-b -estradiol; whereas the lyophilized juice by itself displayed only minimal estrogenic action. inhibition of cell lines by fermented juice and pericarp polyphenols was according to estrogen-dependent (mcf-7) > > estrogen-independent (mb-mda-231) > normal human breast epithelial cells (mcf-10a). in both mcf-7 and mb-mda-231 cells, fermented pomegranate juice polyphenols consistently displayed about twice the anti-proliferative effect as fresh pomegranate juice polyphenols. pomegranate seed oil elicited 90% inhibition of proliferation of mcf-7 at 100 m g/ml medium, 75% inhibition of invasion of mcf-7 across a matrigel membrane at 10 m g/ml, and 54% apoptosis in mda-mb-435 estrogen receptor negative metastatic human breast cancer cells at 50 m g/ml. in a murine mammary gland organ culture, fermented juice polyphenols effected 47% inhibition of cancerous lesion formation induced by the carcinogen 7,12-dimethylbenz[a] anthracene (dmba). pomegranate seed oil and fermented pomegranate juice polyphenols were found to have anti-angiogenic activity (toi et al. 2003 ) . in-vitro studies showed that these pomegranate fractions strongly suppressed vascular endothelial growth factor in normal human breast epithelial cells (mcf-10a) and in estrogen sensitive (mcf-7) human breast cancer cells, but upregulated migration inhibitory factor in estrogen resistant (mda-mb-231) human breast cancer cells. an anti-proliferative effect on angiogenic cells was shown in human umbilical vein endothelial cell (huvec) and in myometrial and amniotic fl uid fi broblasts, and inhibition of huvec tubule formation was also demonstrated in an invitro model employing glass carrier beads. additionally, they showed a signi fi cant reduction in new blood vessel formation using the chicken chorioallantoic membrane (cam) model in-vivo. in another study, pretreatment of mouse mammary organ culture with pomegranate fermented juice polyphenols (w), a high-performance liquid chromatographic (hplc) peak separated from w (peak b), or pomegranate seed oil prior to exposure to the to the carcinogen 7,12-dimethylbenz[a] anthracene (dmba) resulted in a 42% reduction in the number of lesions for w compared with control, peak b and pomegranate seed oil each effected an 87% reduction (mehta and lansky 2004 ) . both pomegranate extracts and genistein inhibit the growth of mcf-7 breast cancer cells through induction of apoptosis, with combination treatment being more ef fi cacious than single treatments (jeune et al. 2005 ) . more recent studies demonstrated that pomegranate fruit extract dose-dependently inhibited nf-kb-dependent reporter gene expression associated with proliferation, invasion, and motility in aggressive breast cancer phenotypes while suppressing rhoc and rhoa protein expression ) . the bioactive components of the fruit extract comprised mainly ellagitannins and phenolic acids in the aqueous fruit extract and conjugated octadecatrienoic acids in the lipid fruit extract derived from seeds. the results suggested a role of pomegranate fruit extract in lowering the metastatic potential of aggressive breast cancer species. pomegranate extract inhibited the proliferation and viability of mmtv-wnt-1 mouse mammary cancer stem cells in-vitro in a timeand concentration-dependent manner (dai et al. 2010 ) . its constituents ellagic ursolic acid and luteolin also caused a time-and concentrationdependent reduction of cell proliferation and viability, suggesting that they contribute to the inhibitory effect of the extract, while caffeic acid had no effect. the methanolic pomegranate fruit peel extract was found to reduce cell proliferation and induce apoptosis on mcf-7 breast cancer cells (dikmen et al. 2011 ) . in addition, expression of the pro-apoptotic gene bax was increased, and that of the anti-apoptotic gene bcl-2 was decreased after pomegranate extract treatment. the extract exhibited high antioxidant activity and yielded total phenolic content of 331.28 mg of gallic acid equivalents/g of extract with ellagic acid as the most abundant constituent. among the ten pomegranate ellagitanninderived compounds (namely ellagic acid, gallagic acid, urolithins a and b and their acetylated, methylated, and sulfated analogues), urolithin b (ub) was shown to most effectively inhibit aromatase activity in a live breast cancer cell assay (adams et al. 2010 ) . ub signi fi cantly inhibited testosterone-induced mcf-7aro cell proliferation. the remaining test compounds also exhibited antiproliferative activity, but to a lesser degree than ub. the results suggested pomegranate et-derived compounds to have potential for the prevention of estrogen-responsive breast cancers. pomegranate seed linolenic acid isomers, punicic acid and α-eleostearic acid were found to be selective estrogen receptor modulators (serms) in-vitro (tran et al. 2010 ) . punicic acid inhibited (ic 50 ) estrogen receptor (er) α at 7.2 m m, estrogen receptor β at 8.8 m m. α-eleostearic acid (aea) inhibited erα/erβ at 6.5/7.8 m m. punicic acid agonized erα/erβ (ec 50 ) at 1.8/2 m m, antagonizing at 101/80 m m. α-eleostearic acid antagonized erα/erβ at 150/140 m m. both isomers induced erα and erβ mrna expression in mcf-7 breast cancer cells, but not in mda-mb-231 breast cancer cells. punicic acid, an omega-5 fatty acid in pomegranate seed oil, was found capable of inhibiting breast cancer proliferation (grossmann et al. 2010 ) . proliferation was inhibited 92 and 96% for mda-mb-231 and mda-erα7 cells, respectively. further punicic acid induced apoptosis in the mda-mb-231 and mda-erα7 cells by 86 and 91%, respectively compared to untreated control cells and disrupted cellular mitochondrial membrane potential. the results suggested the breast cancer inhibitor properties of punicic acid were dependent on lipid peroxidation and the protein kinase c signalling pathway. treatment of human lung carcinoma a549 cells with pomegranate fruit extract resulted in a decrease in the viability of a549 cells and dosedependent arrest of cells in g0-g1 phase of the cell cycle (khan et al. 2007a, b ) . treatment of cells with pomegranate fruit extract inhibited (i) phosphorylation of mapk proteins, (ii) pi3k, (iii) phosphorylation of akt at thr308, (iv) nf-kappab and ikkα, (v) degradation and phosphorylation of ikappabα, and (vi) ki-67 and pcna. oral administration of pomegranate fruit extract (0.1 and 0.2%, wt/vol) to athymic nude mice implanted with a549 cells resulted in a signi fi cant inhibition in tumour growth. treatment of mice with pomegranate juice prior to exposure to carcinogens benzo(a)pyrene (b(a) p) and n-nitroso-tris-chloroethylurea (ntcu), resulted in statistically signi fi cant lower lung tumour multiplicities than mice treated with carcinogens only (khan et al. 2007a ) . treatment of cells with pomegranate fruit extract caused inhibition of (a) activation of nuclear factor-kappab and ikappabα kinase, (b) degradation and phosphorylation of ikappabα, (c) phosphorylation of mitogen-activated protein kinases (extracellular signal-regulated kinase 1/2, c-jun nh(2)-terminal kinase 1/2, and p38), (d) phosphatidylinositol 3-kinase (p85 and p110), (e) phosphorylation of akt at thr(308), (f) activation of mammalian target of rapamycin signaling, (g) phosphorylation of c-met, and (h) markers of cell proliferation (ki-67 and proliferating cell nuclear antigen) and angiogenesis (inducible nitric oxide synthase, cd31, and vascular endothelial growth factor) in lungs of b(a)p-and ntcu-treated mice. overall, the results suggested that pomegranate fruit extract could be a useful chemopreventive/chemotherapeutic agent against human lung cancer. flavonoid-rich polyphenol fractions from the pomegranate fruit had been reported to exert antiproliferative, anti-invasive, anti-eicosanoid, and pro-apoptotic actions in breast and prostate cancer cells and anti-angiogenic activities in-vitro and in-vivo (kawaii and lansky 2004 ) . they found that various fruit extracts had proportional inhibitory effects on human hl-60 promyelocytic leukemia cell proliferation. fermented pomegranate juice and aqueous extract of pomegranate pericarps were found to be strong promoters of differentiation in all settings, while fresh juice extract showed only a relatively mild differentiation-promoting effect. li et al. ( 2011 ) found that pomegranate ellagitannins bound with gelatin to form self-assembled nanoparticles. ellagitannins encapsulated in nanoparticles were less effective in inducing the early stage of apoptosis on human promyelocytic leukemia cells hl-60. but they had similar effects in inducing late stage of apoptosis and necrosis. differentiation refers to the ability of cancer cells to revert to their normal counterparts, and its induction represents an important noncytotoxic therapy for leukemia, and also breast, prostate, and other solid malignancies (kawaii and lansky 2004 ) . pomegranate emulsion treatment (1 or 10 g/ kg) to rats, started 4 weeks prior to the dietary carcinogen diethylnitrosamine (dena) challenge and continued for 18 weeks thereafter, showed striking chemopreventive activity demonstrated by reduced incidence, number, multiplicity, size and volume of hepatic nodules, precursors of hepatocellular carcinoma (bishayee et al. 2011 ) . both doses of the emulsion signi fi cantly attenuated the number and area of g -glutamyl transpeptidase-positive hepatic foci compared with the dena control. the emulsion also attenuated dena-induced hepatic lipid peroxidation and protein oxidation and elevated protein and messenger rna expression of the hepatic nuclear factor e2-related factor 2 (nrf2). the methanolic extract of punica granatum fl owers was exhibited inhibitory effect on tumour necrosis factor-α (tnf-α, 1 ng/ml)induced cytotoxicity in l929 (murine fi broblast) cells (xie et al. 2008 ) . a new taraxastane-type triterpene, punicanolic acid (1), was isolated from the active fraction (ethyl acetate-soluble fraction) together with four triterpenes (2-5), two galloyl glucoses (6, 7), two fl avones (8, 9) , and b -sitosterol. among the constituents, 1, oleanolic acid (2), maslinic acid (4), 1,2,6-tri (7), and luteolin (8) signi fi cantly inhibited tnf-α-induced cytotoxicity in l929 cells at 30 m m. four pure chemicals, ellagic acid (e), caffeic acid (c), luteolin (l) and punicic acid (p), all important components of the aqueous compartments or oily compartment of pomegranate fruit exhibited anticancerous activities by inhibiting human pc-3 prostate cancer cell invasion of matrigel arti fi cial membranes (lansky et al. 2005a ) . all compounds signi fi cantly inhibited invasion when employed individually. when c, p, and l were equally combined at the same gross dosage (4 m g/ml) as when the compounds were tested individually, a supra-additive inhibition of invasion was observed. pomegranate cold-pressed seed oil, fermented juice polyphenols (w), and pericarp polyphenols (p) each acutely inhibited in-vitro proliferation of human prostate cancer, lncap, pc-3, and du 145 human cancer cell lines (albrecht et al. 2004 ) . these effects were mediated by changes in both cell cycle distribution and induction of apoptosis. for example, the androgen-independent cell line du 145 showed a signi fi cant increase from 11 to 22% in g(2)/m cells by treatment with pomegranate oil (35 m g/ ml) with a modest induction of apoptosis. in other cell lines/treatments, the apoptotic response predominated, for example, in pc-3 cells treated with pomegranate pericarp polyphenols, at least partially through a caspase 3-mediated pathway. all agents potently suppressed pc-3 invasion through matrigel, and furthermore pomegranate pericarp polyphenols and seed oil demonstrated potent inhibition of pc-3 xenograft growth in athymic mice. overall, the study demonstrated signi fi cant antitumour activity of pomegranatederived materials against human prostate cancer. in another study, combinations of the anatomically discrete pomegranate fractions: fermented pomegranate juice polyphenols (w), pomegranate pericarp (peel) polyphenols (p) or pomegranate seed oil (oil) exhibited synergistic prostate cancer suppression (lansky et al. 2005b ) . supraadditive, complementary and synergistic effects were proven in all models. proliferation effects were additionally evaluated with compusyn software median effect analysis and showed a concentration index ci < 1, con fi rming synergy. pomegranate fruit extract (pfe) exhibited antiproliferative and proapoptotic activities against human prostate cancer cells (malik et al. 2005 ; malik and mukhtar 2006 ) . pfe (10-100 m g/ ml; 48 h) treatment of highly aggressive human prostate cancer pc3 cells resulted in a dosedependent inhibition of cell growth/cell viability and induction of apoptosis. immunoblot analysis revealed that pfe treatment of pc3 cells resulted in (i) induction of bax and bak (proapoptotic); (ii) down-regulation of bcl-x(l) and bcl-2 (antiapoptotic); (iii) induction of waf1/p21 and kip1/p27; (iv) a decrease in cyclins d1, d2, and e; and (v) a decrease in cyclin-dependent kinase (cdk) 2, cdk4, and cdk6 expression. findings established the involvement of the cyclin kinase inhibitor-cyclin-cdk network during the antiproliferative effects of pfe. oral administration of pfe (0.1 and 0.2%, wt/vol) to athymic nude mice implanted with androgen-sensitive cwr22rnu1 cells resulted in a signi fi cant inhibition in tumour growth concomitant with a signi fi cant decrease in serum prostate-speci fi c antigen levels. the results suggested that pomegranate juice may have cancer-chemopreventive as well as cancerchemotherapeutic effects against prostate cancer in humans. in a phase ii, simon two-stage clinical trial for men with a rising prostate-speci fi c antigen (psa), daily consumption of pomegranate juice was found to have a positive effect following surgery or radiation for prostate cancer (pantuck et al. 2006 ) . there were no serious adverse events reported and the treatment was well tolerated. mean psa doubling time signi fi cantly increased with treatment from a mean of 15 months at baseline to 54 months posttreatment. in-vitro assays comparing pretreatment and posttreatment patient serum on the growth of human prostate cancer lncap showed a 12% decrease in cell proliferation and a 17% increase in apoptosis, a 23% increase in serum nitric oxide, and signi fi cant reductions in oxidative state and sensitivity to oxidation of serum lipids after versus before pomegranate juice consumption. in further studies, a standardized ellagitannins (ets)-enriched pomegranate extract (pe), signi fi cantly inhibited lapc-4 xenograft growth in severe combined immunode fi cient (scid) mice as compared to vehicle control seeram et al. 2007 ) . ellagic acid and several synthesized urolithins were shown to inhibit the growth of human prostate cancer cap cells in-vitro. the chemopreventive potential of pomegranate ets and localization of their bioactive metabolites in mouse prostate tissue suggested that pomegranate may play a role in cap treatment and chemoprevention. the results of studies demonstrated that an ellagitannin-rich pomegranate extract could inhibit tumour-associated angiogenesis as one of several potential mechanisms for slowing the growth of prostate cancer in chemopreventive applications (sartippour et al. 2008 ) . a pomegranate extract standardized to ellagitannin content (pomx) inhibited the proliferation of lncap and huvec cells signi fi cantly under both normoxic and hypoxic conditions. hif-1α (hypoxia-inducible factor-1α) and vegf (vascular endothelial growth factor) protein levels were also reduced by pomx under hypoxic conditions. pomx decreased prostate cancer xenograft size, tumour vessel density, vascular endothelial growth factor (vegf) peptide levels and hif-1α expression after 4 weeks of treatment in severe combined immunode fi cient (scid) mice. studies showed that pomegranate extract inhibited androgen-independent prostate cancer growth through a nuclear factor-kappabdependent mechanism . pomegranate extract (pe) inhibited nf-kappab and cell viability of prostate cancer cell lines in a dose-dependent fashion in vitro. maximal pe-induced apoptosis was dependent on pe-mediated nf-kappab blockade. in the lapc4 xenograft model, pe delayed the emergence of lapc4 androgen-independent xenografts in castrated mice through an inhibition of proliferation and induction of apoptosis. the scientist also showed that pomegranate polyphenols inhibited gene expression and androgen receptor (ar) most consistently in the human prostate cancer lncap-ar cell line (hong et al. 2008 ) . therefore, inhibition by pomegranate polyphenols of gene expression involved in androgen-synthesizing enzymes and the ar may be of particular importance in androgen-independent prostate cancer cells and the subset of human prostate cancers where ar is up-regulated. koyama et al. ( 2010 ) demonstrated that pomegranate extract derived from rind and arils (minus seeds) inhibited cell proliferation and induced apoptosis in human lapc4 prostate cancer cells by modulation of the igf-igfbp (insulin growth factor -insulin growth factor binding proteins) axis. pomegranate extract treatment also decreased igf-1 mrna expression in a dose-dependent manner indicating that its actions also involved tumour-speci fi c suppression of igf-1. pomegranate peel extracts increased the levels of oxygen radical absorbance capacity (orac) in plasma and the density of lecithin and the levels of zn in prostatitic rats (kuang et al. 2009 ) . it decreased the levels of malondialdehyde of prostate and the activity of acid phosphatase and the number of white blood cell and adjusted the levels of no in plasma compared with the prostatitis model group. the results indicated that pomegranate peel extracts could markedly improve the protective function of oxidation resistance. pomegranate ellagitannins/microbial metabolites were found to have cyp1b1 (a target in prostate cancer chemoprevention) inhibitory activity in prostate cancer cells (kasimsetty et al. 2009 ) . urolithin a, a microbial metabolite, was the most potent uncompetitive inhibitor of cyp1b1-mediated ethoxyresoru fi n-o -deethylase (erod) activity, exhibiting two-fold selectivity over cyp1a1, while urolithin b was a noncompetitive inhibitor with three-fold selectivity. the punicalins and punicalagins exhibited potent cyp1a1 inhibition with 5-10-fold selectivity over cyp1b1. cellular uptake experiments demonstrated a fi ve-fold increase in urolithin uptake by 22rv1 cells. western blots of the cyp1b1 protein indicated that the urolithins interfered with the expression of cyp1b1 protein. thus, urolithins were found to display a dual mode mechanism by decreasing cyp1b1 activity and expression. wang et al. ( 2011 ) showed that in addition to causing cell death of hormonerefractory prostate cancer cells, pomegranate juice also increased cell adhesion and decreased cell migration of the unkilled cells. pomegranate juice was found to upregulate genes involved in cell adhesion such as e-cadherin, intercellular adhesion molecule 1 (icam-1) and down-regulated genes involved in cell migration such as hyaluranan-mediated motility receptor (hmmr) and type i collagen. in addition, pomegranate juice signi fi cantly decreased the level of secreted pro-in fl ammatory cytokines/chemokines such as il-6, il-12p40, il-1 b and rantes, thereby having the potential to decrease in fl ammation and its impact. pomegrante juice also inhibited the ability of the chemokine sdf1 a to chemoattract these cancer cells. faria et al. ( 2007 ) found that pomegranate juice consumption decreased total hepatic cytochrome p450 (cyp) content as well as the expression of cyp1a2 and cyp3a in male mice. prevention of procarcinogen activation through cyp activity/expression inhibition may be involved in pomegranate juice's effect on tumour initiation, promotion, and progression pomegranate juice showed greatest antiproliferative activity against all cell lines namely human oral (kb, cal27), colon (ht-29, hct116, sw480, sw620) and prostate (rwpe-1, 22rv1) tumour cells by inhibiting proliferation from 30 to 100% (seeram et al. 2005a ) . at 100 m g/ml, pomegranate juice, ellagic acid, punicalagin and a standardized total pomegranate tannin (tpt) extract induced apoptosis in ht-29 colon cells. however, in the hct116 colon cells, ellagic acid, punicalagin and tpt but not pomegranate juice induced apoptosis. the trend in antioxidant activity was pomegranate juice > tpt > punicalagin > ellagic acid. their data indicated the superior bioactivity of pomegranate juice compared to its puri fi ed individual polyphenolic active ingredients illustrating the multifactorial effects and chemical synergy of the action of multiple compounds. in further studies, they (adams et al. 2006 ) found that pomegranate juice signi fi cantly suppressed tnf-α-induced cox-2 protein expression by 79%, total pomegranate tannin extract (tpt) 55%, and punicalagin 48% in ht-29 colcon cells. in addition, pomegranate juice reduced phosphorylation of the p65 subunit and binding to the nfkappab response element 6.4-fold, tpt suppressed nfkappab binding ten-fold, punicalagin 3.6fold, whereas ellagic acid was ineffective. pomegranate juice also abolished tnfαinduced akt activation, needed for nfkappab activity. pomegranate fruit rich in ellagitannins may have bene fi cial effects against colon cancer. in the stomach and gut, ellagitannins were reported to be hydrolyzed to release ellagic acid (ea) and were converted by gut microbiota to urolithin a (3,8-dihydroxy-6h-dibenzopyran-6one) type metabolites (sharma et al. 2010 ) . they reported that pomegranate ellagitannin extract, ellagic acid, and their colonic metabolite, urolithin a inhibited wnt signaling, which plays a pivotal role in human colon carcinogenesis, suggesting that et-rich foods may have potential against colon carcinogenesis and that urolithins were relevant bioactive constituents in the colon. studies by gonzález-sarrías et al. ( 2009 ) showed that elagic acid and its colonic metabolites, urolithin-a (3,8-dihydroxy-6h-dibenzo [b,d] pyran-6-one) and urolithin-b (3-hydroxy-6hdibenzo[b,d]pyran-6-one), modulated phase i and phase ii detoxifying enzymes in colon cancer caco-2 cells. ellagic acid and urolithins may exert some blocking chemopreventive effects in the colon but this effect may be critically affected by interfering factors, such as the food matrix nature. saruwatari et al. ( 2008 ) found that pomegranate juice potently inhibited the sulfoconjugation of 1-naphthol in caco-2 human colon carcinoma cells. the inhibition was both doseand culture time-dependent, with a 50% inhibitory concentration (ic 50 ) value of 2.7% (vol/vol). punicalagin, the most abundant antioxidant polyphenol in pomegranate juice, was also found to strongly inhibit sulfoconjugation in caco-2 cells with an ic 50 of 45 m m. additionally pomegranate juice and punicalagin both inhibited phenol sulfotransferase activity in caco-2 cells. the data also suggested that constituents of pomegranate juice, most probably punicalagin, impaired the enteric functions of sulfoconjugation and that this may have effects upon the bioavailability of drugs and other compounds and may be related to the anticarcinogenic properties of pomegranate juice. pomegranate seed oil (pgo) rich in 70% cis (c)9, trans (t)11,c13-18:3 as conjugated linolenic acids (cla) could suppress by azoxymethane -induced colon carcinogenesis, and the inhibition was associated in part with the increased content of cla in the colon and liver and/or increased expression of peroxisome proliferator-activated receptor (ppar) γ protein in the colon mucosa (kohno et al. 2004 ) . pomegranate extract was found to induce cell cycle arrest and alter cellular phenotype of human pancreatic cancer cells panc-1 and aspc-1 (nair et al. 2011 ) studies by weisburg et al. ( 2010 ) showed that pomegranate extract exerted greater antiproliferative effects towards cancer (such as hsc-2 carcinoma), than to normal, cells, isolated from the human oral cavity. the antiproliferative mechanism of pomegranate extract was, in part, by induction of oxidative stress. the mode of cell death was by apoptosis, as activation of caspase-3, and cleavage of parp. reduction of caspase-3 activation and of parp cleavage in cells co-treated with pomegranate extract and either cobalt or pyruvate, respectively, as compared to pomegranate extract alone, indicated that apoptosis was through the prooxidant nature of pomegranate extract. pomegranate seed oil (5%) signi fi cantly decreased mice skin tumour incidence, multiplicity, and 12-o -tetradecanoylphorbol 13-acetate (tpa)-induced ornithine decarboxylase activity, an important event in skin cancer promotion (hora et al. 2003 ) . the results suggested the potential of pomegranate seed oil as a safe and effective chemopreventive agent against skin cancer. afaq et al. ( 2005a, b ) demonstrated that topical application of pomegranate fruit extract (pfe) prior to 12-o -tetradecanoylphorbol-13-acetate (tpa) application on mouse skin afforded signi fi cant time-dependent inhibition, against tpa-mediated increase in skin edema and hyperplasia, epidermal ornithine decarboxylase (odc) activity and protein expression of odc and cyclooxygenase-2. also, application of pfe resulted in inhibition of tpa-induced phosphorylation of erk1/2, p38 and jnk1/2, as well as activation of nf-kappab and ikkα and phosphorylation and degradation of ikappabα. pretreatment of pfe on tpa-induced skin tumour promotion in 7,12-dimethylbenz(a)anthracene-initiated cd-1 mouse substantially reduced tumour incidence and lower tumour body burden when assessed as total number of tumours per group, percent of mice with tumours and number of tumours per animal as compared to animals that did not receive pfe. skin application of pfe prior to tpa application also resulted in a signi fi cant delay in latency period from 9 to 14 weeks and afforded protection when tumour data were considered in terms of tumour incidence and tumour multiplicity. studies by george et al. ( 2011 ) suggested that pomegranate fruit extract (pfe) and diallyl sul fi de (das) in combination afforded better suppressive activity of mouse skin tumours than either of these agents alone. pfe and das alone delayed onset and tumour incidence by ~ 55 and ~ 45%, respectively, while their combination at low doses synergistically decreased tumour incidence more potentially (~84%,). further, regression in tumour volume was seen with continuous combinatorial treatment. the inhibition was associated with decreased expression of phosphorylated erk1/2, jnk1 and activated nf-k b/p65, ikk a , i k b a phosphorylation and degradation in skin tissue/ tumour. polysaccharide (psp001) isolated from pomegranate rind was found to have antioxidant, antitumour and immunomodulatory properties (joseph et al. 2012 ) . psp001 exhibited a dosedependent enhancement in antioxidant activity using concentrations from 10 to 1,000 m g/ml when evaluated using various assays such as, ferric reducing antioxidant power assay, linoleic acid emulsion thiocyanate assay, and superoxide, hydroxyl and nitric oxide radical scavenging assays except for the dpph assay for which the highest activity was obtained at 200 m g/ml. psp001 exhibited anticancer activity with ic 50 values of 97.21 and 52.8 m g/-ml following 72 h incubation for mcf-7 (breast cancer), and k562(leukemia) cells, respectively. all the pomegranate peel extracts (ethyl acetate (etoac), acetone, methanol and water) decreased sodium azide mutagènicity in salmonella typhimurium strains (ta100 and ta1535), either weakly or strongly (negi et al. 2003 ) . at 2,500 m g/ plate all the extracts showed strong antimutagenicity. the antimutagenicity of the water extract was followed by acetone, etoac and methanol extracts. the methanol pomegranate peel fraction with promising antioxidant activity showed antimutagenic activity against sodium azide and methyl methane sulphonate with percent inhibition of mutagenicity ranging from 66.76 to 91.86% in a concentration-dependent manner using the ames salmonella/microsome assay (zahin et al. 2010a ) . similar trend of inhibition of mutagenicity (81.2-88.58%) against indirect mutagens (2-amino fl uorene and benzo(a)pyrene) was also recorded. phytochemical analysis by hplc, lc-ms of total phenolic content revealed high content of ellagitannins which might be responsible for promising antioxidant and antimutagenic activities of p. granatum peel extract. methanol extract of punica granatum fl owers (15 mg/plate) showed the highest antimutagenic activity in salmonella typhimurium ta 98 and ta 100, respectively (wongwattanasathien et al. 2010 ) . the protective effects of these fl ower extracts might be due to the presence of antimutagenic components that were supposed to be fl avonoids. studies demonstrated that tannin from the pericarp of punica granatum was an effective agent against genital herpes simplex virus (hsv-2) (zhang et al. 1995 ) . the tannin not only inhibited hsv-2 replication, but also showed stronger effects of killing virus and blocking its absorption to cells. punica granatum extract showed anti-human herpes simplex virus type 1 (hsv-1) activity, which was possibly contributed by the polyphenolic compounds in the herbal extract (li et al. 2004 ) . studies by neurath et al. ( 2005 ) indicated that hiv-1 entry inhibitors from pomegranate juice adsorbed onto corn starch and the resulting complex blocked virus binding to cd4 and cxcr4/ccr5 and inhibited infection by primary virus clades a to g and group o. their results suggested the possibility of producing an anti-hiv-1 microbicide from inexpensive, widely available sources. pomegranate juice containing polyphenols, β-sitosterol, sugars and ellagic acid) was reported to inactivate hiv and further shown to inactivate in fl uenza, herpes viruses and poxviruses (kotwal 2008 ) . a formulation consisting of fulvic acid, a complex mixture of compounds was previously reported to render vaccinia virus, hiv and sars virus non-infectious. recently, both fulvic acid and pomegranate juice were shown to inactivate genetically diverse strains of in fl uenza including h5n1, further con fi rming the broad spectrum nature of these agents. sundararajan et al. ( 2010 ) found that the acidity of pomegranate juice and concentrated liquid extract contributed to rapid anti-in fl uenza activity, but this was not a factor with pomegranate polyphenols powder (93%) extract. studies using pomegranate powder extract showed that 5 min treatment at room temperature with 800 m g/ml pomegranate polyphenols resulted in at least a 3log reduction in the titers of in fl uenza viruses pr8 (h1n1), x31 (h3n2), and a reassortant h5n1 virus derived from a human isolate. however, the antiviral activity was less against a coronavirus and reassortant h5n1 in fl uenza viruses derived from avian isolates. electron microscopic analysis indicated that viral inactivation by pomegranate polyphenols was primarily a consequence of virion structural damage. pomegranate polyphenol extract was shown to have anti-in fl uenza virus properties (haidari et al. 2009 ) . of four major polyphenols in pomegranate polyphenol extract (ppe) (ellagic acid, caffeic acid, luteolin, and punicalagin) punicalagin was the effective, anti-in fl uenza component. punicalagin blocked replication of the virus rna, inhibited agglutination of chicken rbc's by the virus and had virucidal effects. further, the combination of ppe and oseltamivir synergistically increased the anti-in fl uenza effect of oseltamivir. the data showed ppe inhibited the replication of human in fl uenza a/ hong kong (h3n2) virus in-vitro. exposure of foodborne virus surrogates feline calicivirus (fcv-f9), murine norovirus (mnv-1), and ms2 (ssrna) bacteriophage to pomegranate juice and pomegranate polyphenols resulted in titer reductions after one hour at room temperature, suggesting promise for use in hurdle technologies and/or for therapeutic or preventive use (su et al. 2010 ) . ethanolic extracts of garcinia mangostana , punica granatum and quercus infectoria were found to have good antimicrobial activity of nine thai medicinal plants with mics for methicillin-resistant staphylococcus aureus (mrsa) isolates of 0.05-0.4, 0.2-0.4 and 0.2-0.4 mg/ml, respectively, and for s. aureus atcc 25923 of 0.1, 0.2 and 0.1 mg/ml, respectively (voravuthikunchai and d kitpipit 2005 ) . mbcs for mrsa isolates were 0.1-0.4, 1.6-3.2 and 0.4-1.6 mg/ml, and for s. aureus atcc 25923 were 0.4, 3.2 and 1.6 mg/ml, respectively. punica granatum was found to have anti-quorum-sensing activity and may be useful in combating pathogenic bacteria and reduce the development of antibiotic resistance (koh and tham 2011 ; zahin et al. 2010b ) . in another study the ethanolic extract of p. granatum exhibited bacteriostatic and bactericidal activities against two enterohemorrhagic escherichia coli strains (voravuthikunchai and limsuwan 2006 (pai et al. 2010 ) . ethanol extract of p. granatum exhibited strong antibacterial activity against escherichia coli (sharma et al. 2009 ) . studies showed that punica granatum (pomegranate) methanolic extract (pgme) dramatically enhanced the activity of all antibiotics tested (braga et al. 2005a ) . synergic activity was detected between pgme and the fi ve antibiotics tested, chloramphenicol, gentamicin, ampicillin, tetracycline, and oxacillin, ranging from 38 to 73%. using pgme (0.1 × mic) in combination with ampicillin (0.5 × mic), cell viability was reduced by 99.9 and 72.5% in methicillin-sensitive staphylococcus aureus (mssa) and methicillin-resistant staphylococcus aureus (mrsa) populations, respectively. pgme increased the post-antibiotic effect (pae) of ampicillin from 3 to 7 h. pomegranate extract inhibited staphylococcus aureus growth and subsequent enterotoxin production (braga et al. 2005b ) . of several thai medicinal plants, the ethanol extract of p. granatum fruit rind displayed the most outstanding in-vitro antibacterial activity with mic of 0.39 and 12.5 mg/ml and mbc of 1.56 and 12.5 mg/ml against staphylococcus aureus and escherichia coli respectively (chansakaow et al. 2005 ) . the extract was found to contain both hydrolysable and condensed tannins. the methanol pomegranate pericarp extract exhibited maximum antibacterial activity against salmonella typhimurium , salmonella typhi and shigella dysenteriae serotype 1 (pradeep et al. 2008 ) . studies showed that the antibacterial activity of pomegranate rind can be enhanced by the addition of metal salts and vitamin c (mccarrell et al. 2008 ) . pomegranate rind extracts (pre) exhibited activity against the gram positive organisms at 24 h were inactive against gram negative bacteria. addition of cu 2+ salts to pre solutions extended the activities resulting in no detectable growth being observed for the pre/cu 2+ combination against escherichia coli , pseudomonas aeruginosa and proteus mirabilis . minimal antimicrobial activity was observed following incubation with fe 2+ , mn 2+ or zn 2+ salts alone or in combination with pre against any of the organisms in the test panel. the addition of vitamin c markedly enhanced the activities of both pre/fe 2+ and pre/cu 2+ combinations against staphylococcus aureus . pelargonidin-3-galactose, cyanidin-3-glucose, gallic acid, quercetin, and myricetin isolated from the methanolic extract of pomegranate fruit exhibited appreciable activity against species of corynebacteria , staphylococcus , streptococcus , shigella , salmonella , bacillus subtilis , vibrio cholera , and escherichia coli (naz et al. 2007 ) . however, all these compounds were more inhibitory against gram-positive species. gallic acid exerted the highest inhibitory activity against all the tested bacteria. various tannin-rich fractions from pomegranate byproduct and the ellagitannins, ellagic acid (1), gallagic acid (2), punicalins (3), and punicalagins (4) displayed antimicrobial activity when assayed against escherichia coli , pseudomonas aeruginosa , candida albicans , cryptococcus neoformans , methicillin-resistant staphylococcus aureus (mrsa), aspergillus fumigatus and mycobacterium intracellulare (reddy et al. 2007 ) . compounds 2 and 4 showed activity against p. aeruginosa , c. neoformans , and mrsa. a new antifungal peptide designated as pomegranin, isolated from fresh pomegranate peels, was found to inhibit mycelial growth of the fungi botrytis cinerea and fusarium oxysporum with an ic 50 of 2 and 6.1 m m, respectively (guo et al. 2009 ) . lyophilized pomegranate juice (lpj) exhibited antilisterial activity in-vitro and in ground beef (lucas and were 2009 ) . against fi ve listeria monocytogenes strains, lpj had a mic of 1.50-1.75% (wt/vol). the lpj (0, 30, 60, and 120 min of heating) signi fi cantly inhibited growth of all fi ve l. monocytogenes strains in refrigerated ground cooked beef by 1.80-4.61 log cfu/g at day 21. heating did not negatively impact lpj antilisterial activity. ethanol peel extract of pomegranate exhibited in-vitro and in-vivo antimicrobial activity against salmonella typhimurium (choi et al. 2011 ) . the minimal inhibitory concentrations of their extract were in the range of 62.5-1,000 m g/ml. in a s. typhimurium infection mouse model. the extract was found to have signi fi cant effects on mortality and the numbers of viable s. typhimurium recovered from faeces. although clinical signs and histological damage were rarely observed in the treated mice, the untreated controls showed signs of lethargy and histological damage in the liver and spleen. the results of this study indicated that the peel extract had the potential to provide an effective treatment for salmonellosis. studies on patients with denture stomatitis showed that gel extract of p. granatum may be used as a topical antifungal agent for the treatment of candidosis associated with denture stomatitis (vasconcelos et al. 2003 ) . in subsequent studies, punica granatum phytotherapeutic gel and miconazole (daktarin oral gel) exhibited antimicrobial effect against three standard streptococci strains ( streptococcus mutans , streptococcus sanguis and streptococcus mitis ), s. mutans clinically isolated and candida albicans either alone or in association (vasconcelos et al. 2006 ) . the minimum inhibitory concentrations of adherence of punica granatum gel against the test organisms were: 1:16 for s. mutans (atcc), s. mutans (ci) and s. sanguis ; 1:128 for s. mitis and 1:64 for c. albicans . the minimum inhibitory concentrations of adherence of miconazole against the same organisms were: 1:512, 1:64, 1:4, 1:128 and 1:16, respectively. in experiments with three and four associated microorganisms, the punica granatum gel had greater ef fi ciency in inhibiting microbial adherence than the miconazole. the results of this study suggest that this phytotherapeutic agent might be used in the control of adherence of different microorganisms in the oral cavity. studies showed that the hydroalcoholic extract from punica granatu m fruits was very effective against dental plaque microorganisms, decreasing the colony forming units per milliliter (cfu/ml) by 84% (menezes et al. 2006 ) . while similar values were observed with chlorhexidine, used as standard and positive control (79% inhibition). however, another study found that the gel containing 10% punica granatum extract was not ef fi cient in preventing supragingival dental plaque formation and gingivitis (salgado et al. 2006 ) . methanolic extract of pomegranate peel exhibited antibacterial activity against oral pathogens: staphylococcus aureus and s. epidermidis (abdollahzadeh et al. 2011 ) . only at concentration of 8 mg/ml and 12 mg/ml the extract was effective against lactobacillus acidophilus , streptococcus mutans and streptococcus salivarius . the extract did not inhibit actinomyces viscosus and candida albicans . pomegranate rind extract (pre) singularly showed limited ef fi cacy against methicillin-sensitive and -resistant staphylococcus aureus ( mssa, mrsa) respectively but in combination with cu(ii) ions (cupric sulphate), it exhibited moderate antimicrobial effects against clinical isolates of mssa, mrsa and panton-valentine leukocidin positive community acquired mssa (pvl positive ca-mssa) isolates. (gould et al. 2009 ) . sastravaha et al. ( 2005 ) showed that adjunctive local delivery of extracts from centella asiatica in combination with p. granatum signi fi cantly improved clinical signs of chronic periodontitis such probing pocket depth, attachment level, gingival index at 3 and 6 months and of bleeding index at 6 months in the test group as compared to control. no signi fi cant differences in plaque index were found between the two treatment modalities. the test group also showed statistically greater reduction of interleukin il-1β at both 3 and 6 months and lower il-6 concentration. a study of young adults showed that 4 weeks of thrice daily mouth rinsing with the extract improved salivary measures relevant to oral health including gingivitis (disilvestro et al. 2009 ) . salivary changes observed included a reduction in total protein (associated with plaque forming bacteria readings), activities of aspartate aminotransferase (an indicator of cell injury) and α-glucosidase activity (a sucrose degrading enzyme). the changes also included increased activities of the antioxidant enzyme ceruloplasmin and radical scavenging capacity. pomegranate mouth-rinse was found to have an antiplaque effect (bhadbhade et al. 2011 ) . aggregatibacter actinomycetemcomitans , porphyromonas gingivalis , and prevotella intermedia strains in-vitro. pomegranate mouth-rinse could be explored as a long-term antiplaque rinse with prophylactic bene fi ts. probiotication improved the antioxidant activity of sweet pomegranate aril juice from 74.4 to 91.82%, and sour pomegranate juice from 82.64 to 97.8% (fazeli et al. 2011 ) . based on the ferric reducing antioxidant power (frap) value, the reducing power of the probioticated pomegranate juices was also much stronger than the nonprobioticated juices. the frap values for sweet and sour probioticated pomegranate juices were 97.34 and 120.7 mmol/l, respectively, which were notably higher than 85.87 and 93.4 mmol/l for sweet and sour nonprobioticated juices. total counts of lactobacillus casei gg increased by about three log in sweet and two log in sour juices after 48 h incubation. both fermentated and nonfermentated juices exhibited a potent and widespectrum antibacterial effect, with the highest activity against pseudomonas aeruginosa with the sweet juice showing wider zones of growth inhibition. the results showed that probiotication of sweet and sour pomegranate juices could add to their bene fi cial antioxidant activities. pomegranate byproducts and punicalagins inhibited the growth of pathogenic clostridia and staphylococcus aureus (bialonska et al. 2009b ) . the growth of probiotic lactobacilli and bi fi dobacteria were generally not affected by ellagitannins. the effect of pomegranate ellagitannins on bi fi dobacteria was species-and tannin-dependent. the growth of bi fi dobacterium animalis ssp. lactis was slightly inhibited by punicalagins, punicalins, and ellagic acid. pomegranate ellagitannin-enriched polyphenol extract (pomx) supplementation signi fi cantly enhanced the growth of bi fi dobacterium breve and bi fi dobacterium infantis. bialonska et al. ( 2009a ) found that products of the intestinal microbial transformation of pomegranate ellagitannins may account for systemic antioxidant effects. while moving through the intestines, pomegranate ellagitannins namely ellagic acid and punicalagins are metabolized by gut bacteria into urolithins that readily enter systemic circulation. their study found that the antioxidant activity of urolithins was correlated with the number of hydroxy groups as well as the lipophilicity of the molecule. the most potent antioxidants were urolithins c and d with ic 50 values of 0.16 and 0.33 m m, respectively, when compared to ic 50 values of 1.1 and 1.4 m m of the parent ellagic acid and punicalagins, respectively. the dihydroxylated urolithin a showed weaker antioxidant activity, with an ic 50 value 13.6 m m, however, the potency was within the range of urolithin a plasma concentrations. numerous laboratory research, animal and human pilot studies had reported on the effectiveness of pomegranate fruit, pomegranate juice and pomegranate fruit polypehnols in reducing heart disease risk factors ldl oxidation, blood pressure, serum angiotensin converting enzyme (ace) activity, cholesterol esteri fi cation, macrophage oxidative status, and macrophage foam cell formation, all of which are steps in atherosclerosis and cardiovascular disease (aviram et al. 2000 (aviram et al. , 2002 (aviram et al. , 2004 aviram and dornfeld 2001 ; kaplan et al. 2001 ; esmaillzadeh et al. 2004 ; fuhrman et al. 2005 ; de nigris et al. 2005 ; rosenblat et al. 2006a, b ; fuhrman and aviram 2007 ; bagri et al. 2009 ) . in healthy humans, pomegranate juice consumption decreased ldl susceptibility to aggregation and retention and increased the activity of serum paraoxonase by 20% (aviram et al. 2000 ) . paraoxanase an hdlassociated esterase, could protect against lipid peroxidation. in apolipoprotein e-de fi cient e o mice, oxidation of ldl by peritoneal macrophages was reduced by up to 90% after pomegranate juice consumption and this effect was associated with reduced cellular lipid peroxidation and superoxide release. the uptake of oxidized ldl and native ldl by mouse peritoneal macrophages obtained after pomegranate juice administration was reduced by 20%. further, pomegranate juice supplementation of e o mice reduced the size of their atherosclerotic lesions by 44% and also the number of foam cells compared with control e o mice supplemented with water. the potent antiatherogenic effects in healthy humans and in atherosclerotic mice may be attributable to its antioxidative properties. anti-atherosclerotic properties was attributed to pomegranate potent anti-oxidative characteristics. after consumption of pomegranate juice, a 36% reduction in serum angiotensin converting enzyme (ace) activity and a 5% reduction in systolic blood pressure were noted in hypertensive patients . similar dose-dependent inhibitory effect (31%) of pomegranate juice on serum ace activity was observed also in-vitro. additional studies showed that pomegranate juice supplementation to atherosclerotic mice reduced macrophage lipid peroxidation, cellular cholesterol accumulation and development of atherosclerosis (kaplan et al. 2001 ) . pomegranate juice supplementation reduced each of the proatherogenic variables. it signi fi cantly induced serum paraoxonase activity and reduced mouse peritoneal macrophage (mpm) lipid peroxide content compared with placebo-treated mice and control mice. pomegranate juice administration to apolipoprotein e-de fi cient e o mice signi fi cantly reduced the oxidized (ox)-ldl mpm uptake by 31% and mpm cholesterol esteri fi cation and increased macrophage cholesterol ef fl ux by 39% compared with age-matched, placebo-treated mice. pomegranate juice consumption reduced macrophage ox-ldl uptake and cholesterol esteri fi cation to levels lower than those in 4-month-old, unsupplemented controls. pomegranate juice supplementation to e o mice with advanced atherosclerosis reduced the lesion size by 17% compared with place botreated mice. in a separate study, supple mentation of young (2-month-old) e o mice for 2 months with a tannin fraction isolated from pomegranate juice reduced their atherosclerotic lesion size, paralleled by reduced plasma lipid peroxidation and decreased ox-ldl mpm uptake. studies indicated that the proatherogenic effects induced by perturbed shear stress in cultured human coronary artery endothelial cells could be reversed by chronic administration of pomegranate juice (de nigris et al. 2005 (de nigris et al. , 2007 . pomegranate juice concentrate and pomegranate fruit extract rich in punicalagin reduced the activation of redox-sensitive genes elk-1, p-jun, p-creb, and increased enos expression (which was decreased by perturbed shear stress) in cultured endothelial cells and in atherosclerosis-prone areas of hypercholesterolemic mice. furthermore, oral administration of pomegranate juice to hypercholesterolemic mice at various stages of disease reduced signi fi cantly the progression of atherosclerosis and isoprostane levels and increased nitrates. de found that pomegranate juice reverted the potent downregulation of the expression of endothelial nitricoxide synthase (nosiii) induced by oxidized low-density lipoprotein (oxldl) in human coronary endothelial cells. their data suggested that pomegranate juice could exert bene fi cial effects on the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in humans by enhancing the nitric-oxide synthase bioactivity. aviram et al. ( 2002 ) reported that pomegranate polyphenols protected low-density lipoprotein (ldl) against cell-mediated oxidation via two pathways, including either direct interaction of the polyphenols with the lipoprotein and/or an indirect effect through accumulation of polyphenols in arterial macrophages (aviram et al. 2002 ) . pomegranate polyphenols were shown to reduce the capacity of macrophages to oxidatively modify ldl, due to their interaction with ldl to inhibit its oxidation by scavenging reactive oxygen species and reactive nitrogen species and also due to accumulation of polyphenols in arterial macrophages; hence, the inhibition of macrophage lipid peroxidation and the formation of lipid peroxide-rich macrophages. additionally, pomegranate polyphenols increased serum paraoxonase activity, resulting in the hydrolysis of lipid peroxides in oxidized lipoproteins and in atherosclerotic lesions. these antioxidative and antiatherogenic effects of pomegranate polyphenols were demonstrated in-vitro, as well as in-vivo in humans and in atherosclerotic apolipoprotein e de fi cient mice. dietary supplementation of polyphenol-rich pomegranate juice to atherosclerotic mice signi fi cantly inhibited the development of atherosclerotic lesions and this may be attributed to the protection of ldl against oxidation. subsequent studies indicated that that pomegranate juice consumption by patients with carotid artery stenosis cas decreased carotid carotid intima-media thickness (imt) and systolic blood pressure and these effects could be related to the potent antioxidant characteristics of pomegranate juice polyphenols (aviram et al. 2004 ) . for all studied parameters, the maximal effects were observed after 1 year of pomegranate juice consumption. further consumption of pomegranate juice, for up to 3 years, had no additional bene fi cial effects on imt and serum paraoxonase 1 (pon 1) activity, whereas serum lipid peroxidation was further reduced by up to 16% after 3 years of pomegranate juice consumption. the antiatherogenic properties of pomegranate juice (pj) were attributed to its antioxidant potency and to its capacity to decrease macrophage oxidative stress, the hallmark of early atherogeneis (rosenberg et al. 2006 ). pomegranate juice polyphenols and sugar-containing polyphenolic anthocyanins were shown to confer pj its antioxidant capacity. their study showed that pj sugar consumption by diabetic mice for 10 days resulted in a small but signi fi cant decrement in their peritoneal macrophage total peroxide levels and an increment in cellular glutathione content, compared to mouse peritoneal macrophages harvested from control diabetic mice administrated with water. these antioxidant/antiatherogenic effects could be due to the presence of unique complex sugars and/or phenolic sugars in pj. they further showed the anti-oxidative characteristics of pj unique phenolics punicalagin and gallic acid could be related, at least in part, to their stimulatory effect on macrophage paraoxonase 2 (pon2) expression, a phenomenon which was shown to be associated with activation of the transcription factors papr γ and ap-1 (shiner et al. 2007 ) . similar results were obtained by pomegranate byproduct (which includes the whole pomegranate fruit left after juice preparation) (17 or 51.5 m g of gallic acid equiv/kg/day) administration to apolipoprotein e-de fi cient mice that resulted in attenuation of atherosclerosis development as a result of decreased macrophage oxidative stress and reduced cellular uptake of oxidized low-density lipoprotein (rosenblat et al. 2006 ) . in-vitro studies showed that preincubation of j774.a1 macrophages with pomegranate juice resulted in a signi fi cant reduction in ox-ldl degradation by 40% (fuhrman et al. 2005 ) . macrophage cholesterol biosynthesis was inhibited by 50% after cell incubation with pomegranate juice. this inhibition, however, was not mediated at the 3-hydroxy-3 methylglutaryl coenzyme a reductase level along the biosynthetic pathway. it was concluded that pomegranate juice-mediated suppression of ox-ldl degradation and of cholesterol biosynthesis in macrophages could lead to reduced cellular cholesterol accumulation and foam cell formation. studies in iran reported that consumption of concentrated pomegranate juice may modify heart disease risk factors in hyperlipidemic ( cholesterol ³ 5.2 mmol/l or triacylglycerol ³ 2.3 mmol/l) patients (esmaillzadeh et al. 2004 (esmaillzadeh et al. , 2006 . after consumption of concentrated pomegranate juice, signi fi cant reductions were seen in total cholesterol, low-density lipoprotein (ldl)-cholesterol, ldl-cholesterol/high-density lipoprotein (hdl)-cholesterol, and total cholesterol/hdl-cholesterol. but, there were no signi fi cant changes in serum triacylglycerol and hdl-cholesterol concentrations. anthropometric indices, physical activity, kind and doses of oral hypoglycemic agents, and the intakes of nutrients and fl avonoid-rich foods showed no change during the concentrated pomegranate juice consumption period. rosenblat et al. ( 2006 ) reported that pomegranate juice consumption by diabetic patients did not affect serum glucose, cholesterol and triglyceride levels, but it resulted in a signi fi cant reduction in serum lipid peroxides and tbars (thiobarbituric acid reactive substance) levels by 56 and 28%, whereas serum sh (sulfhydryl) groups and paraoxonase 1 (pon1) activity signi fi cantly increased by 12 and 24%, respectively. in the patients versus controls monocytes-derived macrophages (hmdm), they observed increased level of cellular peroxides (by 36%), and decreased glutathione content (by 64%). pomegranate juice consumption signi fi cantly reduced cellular peroxides (by 71%), and increased glutathione levels (by 141%) in the patients' hmdm. the patients' versus control hmdm took up oxidized ldl (ox-ldl) at enhanced rate (by 37%) and pomegranate juice consumption signi fi cantly decreased the extent of ox-ldl cellular uptake (by 39%). they thus concluded that pomegranate juice consumption by diabetic patients did not worsen the diabetic parameters, but rather resulted in anti-oxidative effects on serum and macrophages, which could contribute to attenuation of atherosclerosis development in these patients. pomegranate juice was found to have potent antiatherogenic activity . in-vitro studies demonstrated a pomegranate juice dose-dependent antioxidant capability against lipid peroxidation in plasma (by 33%), in ldl (by 43%), and in hdl (by 22%). pomegranate juice consumption by hypertensive patients reduced their systolic blood pressure (by 6%), along with inhibition (by 40%) of angiotensin converting enzyme (ace). pomegranate juice supplementation to atherosclerotic apolipoprotein e-de fi cient (e°) mice reduced their atherosclerotic lesion size by 44% and the number of foam cells in their lesion. consumption of pomegranate juice by ten patients with carotid artery stenosis (cas) for 1 year reduced the patients' carotid intima-media thickness (imt) by 32%. these effects were associated with exvivo reduced lipid peroxidation in plasma and in isolated lipoproteins in humans and mice. furthermore, pomegranate juice consumption by humans increased the activity of their serum paraoxonase (pon1), an hdl-associated esterase that protects against lipid peroxidation. macrophage atherogenicity was studied in mouse peritoneal macrophages (mpm) harvested from e° mice. following pomegranate juice consumption, uptake of oxidized ldl and cell-mediated oxidation of ldl by macrophages was reduced by 88 and by 20%, respectively, in association with reduced cellular lipid peroxidation, reduced superoxide anion release due to decreased nadph-oxidase activation, and elevated glutathione content. in-vitro studies demonstrated that pomegranate juice reduced macrophage ox-ldl degradation by 40%, and macrophage cholesterol biosynthesis by 50%. overall, the results of the above studies demonstrated that pomegranate juice consumption had very potent antiatherogenic properties, which could be associated mainly with pomegranate juice hydrolysable tannin antioxidative properties. in a recent study ) pomegranate juice (pj), fruit peels (pomxl, pomxp), arils (poma), seeds (pomo), and fl owers (pomf), extracts all were found to possess antioxidative properties in-vitro. after consumption of pomegranate juice, fruit peel, aril and fl ower extracts the atherosclerotic lesion area in atherosclerotic apolipoprotein e-de fi cient (e 0) mice was signi fi cantly decreased by 44, 38, 39, 6, or 70%, respectively, as compared to placebo-treated group, while pomegranate seed oil had no effect. pomegrante fl ower consumption reduced serum lipids, and glucose levels by 18-25%. consumption of the extracts except for the seed oil resulted in a signi fi cant decrement, by 53, 42, 35, 27, or 13%, respectively, in mpm (mouse peritoneal macrophage) total peroxides content, and increased cellular paraoxonase 2 (pon2) activity, as compared to placebo-treated mice. the uptake rates of oxidized-ldl by e (0)-mpm were signi fi cantly reduced by approximately 15% after consumption of juice and the two fruit peel extracts. similar results were obtained on using j774a.1 macrophage cell line. finally, pomegranate phenolics (punicalagin, punicalin, gallic acid, and ellagic acid), as well as pomegranate unique complexed sugars, could mimic the antiatherogenic effects of the pomegranate extracts. rock et al. ( 2008 ) reported that after 4 weeks of pomegranate juice consumption by male patients, basal serum oxidative stress was signi fi cantly decreased by 35%, whereas serum concentrations of thiol groups signi fi cantly increased by 25%. moreover, hdlassociated paraoxonase 1(pon1), arylesterase, paraoxonase, and lactonase activities increased signi fi cantly after pomegranate juice consumption by 34-45%, as compared to the baseline levels. pon1 protein binding to hdl was signi fi cantly increased by 30% following pomegranate juice consumption, and the enzyme became more stable. in male patients that consumed pomegranate polyphenol extract and in female patients that consumed pomegranate juice, a similar pattern was observed, although to a lesser extent. these bene fi cial effects of pomegranate consumption on serum pon1 stability and activity could lead to retardation of atherosclerosis development in diabetic patients. results of a randomized, double-blind, parallel trial involving men (45-74 years old) and women (55-74 years old) with moderate coronary heart disease risk suggested that in subjects at moderate coronary heart disease risk, pomegranate juice consumption had no signi fi cant effect on overall carotid intima-media thickness progression rate but may have slowed carotid intima-media thickness progression in subjects with increased oxidative stress and disturbances in the triglycerides-rich lipoprotein/high-density lipoprotein axis (davidson et al. 2009 ) . lei et al. ( 2007 ) reported that the pomegranate leaf extract could inhibit the development of obesity and hyperlipidemia in high-fat diet induced obese mice. mice treated with the extract presented a signi fi cant decrease in body weight, energy intake and various adipose pad weight percents and serum, serum total cholesterol (tc), triglyceride (tg), glucose levels and tc/highdensity lipoprotein cholesterol (hdl-c) ratio after 5 weeks treatment. further, the extract signi fi cantly attenuated the raising of the serum tg level and inhibited the intestinal fat absorption in mice given a fat emulsion orally. the effects were postulated to be partly mediated by inhibiting the pancreatic lipase activity and suppressing energy intake. yamasaki et al. ( 2006 ) found that mice fed dietary pomegranate seed oil (pso) high in levels of punicic acid showed signi fi cant increases in serum triacylglycerol and phospholipid levels but not in total cholesterol. punicic acid could be detected in serum, liver, and adipose tissues in mice fed the 0.12 or 1.2% pso diet. oral administration of streptozotocin-induced diabetic wistar rats with of 250 and 500 mg/kg of aqueous pomegranate fl ower extract for 21 days resulted in a signi fi cant fall in fasting blood glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol , very low density lipoprotein, lipid peroxidation level (bagri et al. 2009 ) . pomegrante extract elevated levels of high density lipoprotein cholesterol (hdl-c), reduced glutathione (gsh) and the antioxidative enzymes, glutathione peroxidase (gpx), glutathione reductase (gr), glutathione-s-transferase (gst), superoxide dismutase (sod) and catalase (cat). mcfarlin et al. ( 2009 ) found that weight gain in high fat diet mice was associated with an increase in biomarkers of cholesterol pro fi le, glucose sensitivity, adipose tissue accumulation and systemic low-grade in fl ammation. despite a similar level of energy intake, high-fate diet mice had a greater concentration of leptin and a lower concentration of adiponectin compared to high fat + pomegranate seed oil diet mice. pomegranate seed oil, a rich source of 9-cis , 11-trans conjugate linolenic acid, only altered body weight accumulation, fi nal body weight, leptin, adiponectin and insulin. pomegranate seed oil intake was associated with an improvement in insulin sensitivity, suggesting that risk of developing type two diabetes may have been reduced; however, cvd risk did not change. lan et al. ( 2009 ) demonstrated that ellagic acid in pomegranate leaf tannins could be transported into hepg2 cells and this correlated with total cholesterol alteration in the cells. vroegrijk et al. ( 2011 ) found that pomegranate seed oil, a rich source of punicic acid, ameliorated high-fat diet induced obesity and insulin resistance in mice, independent of changes in food intake or energy expenditure. compared to high fat diet mice, its intake resulted in a lower body weight and improved peripheral insulin sensitivity but did not affect liver insulin sensitivity. in a randomized, double-blind, placebo-controlled clinical trial of 20 obese adult volunteer, pomegranate juice administration for 1 month did not modify insulin secretion and sensitivity in the obese patients, however, the natural evolution to increased weight and adiposity was halted (gonzález-ortiz et al. 2011 ) . rosenblat and aviram ( 2011 ) found that the inhibitory effect of pomegranate juice on triglyceride biosynthesis could be attributed to a direct effect of pomegranate juice on the activity of diacylglycerol acyltransferase 1 (dgat1) the rate-limiting enzyme in triglyceride biosynthesis. pomegranate juice and its constituent punicalagin signi fi cantly and dose-dependently decreased the triglyceride content and triglyceride biosynthesis rate in j774a.1 macrophages or in c57bl/6 mouse peritoneal macrophages. both pomegranate juice and punicalagin increased (1.7-fold) mouse peritoneal macrophages paraoxonase 2 (pon2) mrna expression, and pon2 was previously shown to inhibit dgat1 activity. however, the addition of pj or punicalagin (50 m m) to microsomes from pon2-de fi cient mouse peritoneal macrophages still resulted in a signi fi cant reduction (50-58%) in dgat1 activity. in a randomised block design study of student volunteers, supplementation of pomegranate juice caused a fall in diastolic blood pressure and this could be related to ros scavenging activity rather than to angiotensin-converting enzyme inhibitors (wright and pipkin 2008 ) oral administration of pomegranate juice extract (100 and 300 mg/kg) to angiotensin-ii treated rats for 4 weeks signi fi cantly reduced the mean arterial blood pressure and vascular reactivity changes to various catecholamines (waghulde et al. 2010 ) . pomegranate juice administration signi fi cantly decreased the serum levels of ace (angiotensin converting enzyme) and the levels of thiobarbituric acid reactive substances (tbars); while enzyme activity of superoxide dismutase (sod), catalase (cat), glutathione reductase (gsh) in kidney tissue showed a signi fi cant elevation in pomegranate juice treated angiotensin-ii induced hypertensive rats. the results suggested that pomegranate juice extract could prevent the development of high blood pressure induced by angiotensin-ii probably by combating the oxidative stress and antagonizing the physiological actions of angiotensin-ii. chronic administration of pomegranate fruit juice (pj) extract (100 and 300 mg/kg; p.o. for 4 weeks) reduced the mean arterial blood pressure and vascular reactivity changes to various catecholamines and also reversed the biochemical changes induced by diabetes and angiotensin ii (ang ii) (mohan et al. 2010 b ) . acute subcutaneous administration of angiotensin ii causes a rise in blood pressure in streptozotocin-induced diabetic wistar rats. pj treatment also caused a signi fi cant decrease in levels of thiobarbituric acid reactive substances (tbars) in the kidney and pancreas while activities of enzymes superoxide dismutase (sod), catalase (cat), and glutathione reductase (gsh) showed signi fi cant elevation. pj treatment prevented the tubular degenerative changes induced by diabetes. the results suggested that the pj extract could prevent the development of high blood pressure induced by ang ii in diabetic rats probably by combating the oxidative stress induced by diabetes and ang ii and by inhibiting ace activity. pomegranate in particular its fl owers, seeds, and juice have been employed for the treatment of various diseases in traditional unani and ayurvedic systems of medicine in india but only the fl ower has been prescribed for the treatment of diabetic disorders katz et al. 2007 ) . the mechanisms for it hypoglycaemic effects are largely unknown, though recent research suggested pomegranate fl owers and juice may prevent diabetic sequelae via peroxisome proliferator-activated receptor (ppar) α/γ binding and nitric oxide production (katz et al. 2007 ; huang et al. 2005a, b ; li et al. 2008 ; xu et al. 2009 ) . pomegranate compounds associated with such effects include oleanolic, ursolic, and gallic acids (katz et al. 2007 ) . another study suggested that punica granatum fl ower (pgf) extract inhibited increased cardiac fatty acid uptake and oxidation in the diabetic condition (huang et al. 2005b ) . pgf extract and its component oleanolic acid enhanced peroxisome proliferator-activated receptor (ppar)-α luciferase reporter gene activity in human embryonic kidney 293 cells. this effect was completely suppressed by a selective ppar-α antagonist mk-886, consistent with the presence of ppar-α activator activity in the extract and this component. the fi ndings suggested that pgf extract improved abnormal cardiac lipid metabolism in zucker diabetic fatty rats by activating ppar-α and thereby lowering circulating lipid and inhibiting its cardiac uptake. excess triglyceride (tg) accumulation and increased fatty acid (fa) oxidation in the diabetic heart contribute to cardiac dysfunction. in subsequent in-vitro studies, the scientists (huang et al. 2005a ) demonstrated that 6-week oral administration of methanol extract from pgf (500 mg/kg, daily) inhibited glucose loading-induced increase of plasma glucose levels in zucker diabetic fatty rats (zdf), a genetic animal model for type two diabetes, whereas it did not inhibit the increase in zucker lean rats (zl). the treatment did not lower the plasma glucose levels in fasted zdf and zl rats. further, rt-pcr results demonstrated that the pgf extract treatment in zdf rats enhanced cardiac ppar-γ mrna expression and restored the down-regulated cardiac glucose transporter (glut)-4 (the insulin-dependent isoform of gluts) mrna. these results suggest that the anti-diabetic activity of pgf extract may result from improved sensitivity of the insulin receptor. from the in-vitro studies, it was demonstrated that the pgf extract enhanced ppar-γ mrna and protein expression and increased ppar-γ-dependent mrna expression and activity of lipoprotein lipase in human thp-1-differentiated macrophage cells. phytochemical investigation demonstrated that gallic acid in pgf extract was mostly responsible for this activity. further in-vitro studies showed that punica granatum fl ower extract and its components oleanolic acid, ursolic acid, and gallic acid inhibited lipopolysaccharide-induced nf-kappab activation in macrophages. the fi ndings indicated that punica granatum fl ower extract reduced cardiac fi brosis in zucker diabetic fatty rats, at least in part, by modulating cardiac et-1 and nf-kappab signalling. recent studies suggested that pomegranate fl ower (pgf) medicine ameliorated diabetes and obesity-associated fatty liver, at least in part, by activating hepatic expression of genes responsible for fatty acid oxidation ) . pgf-treated zdf rats showed reduced ratio of liver weight to tibia length, hepatic triglyceride contents and lipid droplets. these effects were accompanied by enhanced hepatic gene expression of peroxisome proliferator-activated receptor (ppar)-α, carnitine palmitoyltransferase-1 and acyl-coa oxidase (aco), and reduced stearoyl-coa desaturase-1. in contrast, pgf showed minimal effects on expression of genes responsible for synthesis, hydrolysis or uptake of fatty acid and triglycerides. pgf treatment also increased ppar-α and aco mrna levels in hepg2 cells. li et al. ( 2008 ) reviewed the dual ppar-α/-γ activator properties of pomegranate fl ower and its potential treatment of diabetes and its associated complications. ppars are nuclear transcription factors and are the major regulators of lipid and glucose metabolism. ppar-α is involved in the regulation of fatty acid (fa) uptake and oxidation, in fl ammation and vascular function, while ppar-γ participates in fa uptake and storage, glucose homeostasis and in fl am mation. synthetic ppar-α or ppar-γ agonists have been widely used in the treatment of dyslipidaemia, hyperglycaemia and their complications. however, they are associated with an incidence of adverse events. given the favourable metabolic effects of both ppar-α and ppar-γ activators, as well as their potential to modulate vascular disease, com bined ppar-α/-γ activation has recently emerged as a promising concept, leading to the development of mixed ppar-α/-γ activators. hontecillas et al. ( 2009 ) demonstrated that punicic acid (pua), a conjugated linolenic acid isomer found in pomegranate, caused a dosedependent increase ppar α and γ reporter activity in 3 t3-l1 pre-adipocyte cells and bound although weakly to the ligand-binding domain of human ppar γ. dietary pua decreased fasting plasma glucose concentrations, improved the glucose-normalizing ability, suppressed nf-kappab activation, tnf-α expression and upregulated ppar αand γ-responsive genes in skeletal muscle and adipose tissue. pua improved glucose homeostasis and suppress obesity-related in fl ammation studies in india showed that pomegranate seed extract (150, 300 and 600 mg/kg) administered orally to streptozotocin (stz)-induced diabetic rats caused a signi fi cant reduction of blood glucose levels by 47 and 52%, respectively, at the end of 12 h (das et al. 2001 ) . kim et al. ( 2011 ) found that administration of pomegranate extract to streptozotocin (stz)-induced diabetic mice for 4 weeks improved postprandial glucose regulation. further elevated na(+)-dependent glucose uptake by brush border membrane vesicles isolated from stz mice was normalized by pomegranate treatment. the results suggested that pomegranate extract could play a role in controlling the dietary glucose absorption at the intestinal tract by decreasing sodium-coupled glucose transporter sglt1 expression, and may contribute to blood glucose homeostasis in the diabetic condition. oral administration of pomegranate fl ower (pgf) extract markedly lowered plasma glucose levels in non-fasted zucker diabetic fatty rats (a genetic model of obesity and type two diabetes), whereas it had little effect in the fasted animals, suggesting it affected postprandial hyperglycemia in type two diabetes . the extract was found to markedly inhibit the increase of plasma glucose levels after sucrose loading, but not after glucose loading in mice, and it had no effect on glucose levels in normal mice. in-vitro, pgf extract demonstrated a potent inhibitory effect on α-glucosidase activity (ic 50 : 1.8 m g/ml). these fi ndings strongly suggested that pgf extract improved postprandial hyperglycemia in type two diabetes and obesity, at least in part, by inhibiting intestinal α-glucosidase activity. postprandial hyperglycemia plays an important role in the development of type two diabetes and has been proposed as an independent risk factor for cardiovascular diseases. in a recent paper, bagri et al. ( 2009a ) reported that oral administration of pomegranate aqueous extract at doses of 250 and 500 mg/kg for 21 days to stzinduced diabetic rats resulted in a signi fi cant reduction in fasting blood glucose, total cholesterol (tc), triglycerides (tg), low-density lipoprotein cholesterol (ldl-c), very low density lipoprotein (vldl), and tissue lipid peroxidation levels coupled with elevation of high density lipoprotein cholesterol (hdl-c), glutathione (gsh) content and antioxidant enzymes in comparison with diabetic control group. the results suggested that pg could be used, as a dietary supplement, in the treatment of chronic diseases characterized by atherogenous lipoprotein pro fi le, aggravated antioxidant status and impaired glucose metabolism and also in their prevention. in-vitro studies showed that pomegranate juice polyphenols increased recombinant paraoxonase-1 binding to high-density lipoprotein (hdl) beyond their antioxidative effect (fuhrman et al. 2010 ) . further recombinant paraoxonase-1 was found to be associated more ef fi ciently with hdls isolated from diabetic patients after pomegranate juice consumption versus hdls isolated before pomegranate juice consumption. studies by ahmed et al. ( 2005 ) showed that pomegranate fruit extract or compounds derived from it may inhibit cartilage degradation in osteoarthritis and may also be a useful nutritive supplement for maintaining joint integrity and function. the extract inhibited interleukin (il)-1β induced expression of matrix metalloproteinases by suppressing the activation of mitogen-activated protein kinases and nuclear factor-kappab in human chondrocytes in-vitro. pomegranate methanol extract was found to dose-dependently inhibit tumour necrosis factor α (tnf-α) production in lipopolysaccharide (lps) stimulated cells (jung et al. 2006 ) . the data suggested that the extract may suppress lps-stimulated tnf production through inhibition of nfkappab in bv2 microglia cells. shukla et al. ( 2008b ) reported that consumption of hydrolyzable tannins-rich pomegranate extract potently delayed the onset and reduced the incidence and severity of collagen-induced arthritis in mice. pomegranate extract -fed mice had reduced joint in fi ltration by the in fl ammatory cells, and the destruction of bone and cartilage were alleviated. levels of interleukin il-6 were signi fi cantly decreased in the joints of pomegranate-fed mice with collagen-induced arthritis. in mouse macrophages, pomegranate extract abolished multiple signal transduction pathways and downstream mediators implicated in the pathogenesis of rheumatoid arthritis. in another study, rabbit plasma samples collected after oral ingestion of polyphenol rich pomegranate fruit extract were found to inhibit the il-1β-induced pge2 and no production in chondrocytes (shukla et al. 2008a ) . these same plasma samples also inhibited both cox-1 and cox-2 enzyme activity ex-vivo but the effect was more pronounced on the enzyme activity of cox-2 enzyme. the studies suggested that pomegranate fruit extract-derived bioavailable compounds may exert an anti -in fl ammatory effect by inhibiting the in fl ammatory cytokineinduced production of pge2 and no in-vivo. pomegranate extract rich in polyphenols was found to inhibit the interleukin-1 b -induced activation of mkk-3, p38 a -mapk and transcription factor runx-2 in human osteoarthritis chondrocytes (rasheed et al. 2010 ) . this pharmacological actions of pomegranate extract suggest that the extract or its derived compounds may be developed as mkk and p38-mapk inhibitors for the treatment of osteoarthritis and other degenerative/ in fl ammatory diseases. in a pilot12 week openlabelled study, pomegranate consumption reduced the composite disease activity index (das28) and tender joint count in rheumatoid arthritis patients, and this effect could be related to the antioxidative property of pomegranates (balbir-gurman et al. 2011 ) . the results suggested dietary supplementation with pomegranates may be a useful complementary strategy to attenuate clinical symptoms in rheumatoid arthritis patients. supplementation of obese zucker rats with pomegranate fruit extract (pfe) or pomegranate juice (pj) signi fi cantly decreased the expression of vascular in fl ammation markers, thrombospondin (tsp), and cytokine tgfβ1, whereas seed oil supplementation had a signi fi cant effect only on tsp-1 expression (de nigris et al. 2007a ) . plasma nitrate and nitrite (no(x)) levels were signi fi cantly increased by pfe and pj. in addition, the effect of pfe in increasing endothelial no synthase (enos) expression was comparable to that of pj. the data suggested possible clinical applications of pfe in metabolic syndrome (clinical conditions such as obesity, hypertension, dislipidemia, and diabetes). in-vivo studies revealed that aqueous pomegranate peel extract inhibited neutrophil myeloperoxidase activity and attenuated lipopolysaccharide-induced lung in fl ammation in mice (bachoual et al. 2011 ) . inhibition of myeloperoxidase activity by pomegranate extract could explain its antiin fl ammatory action. balwani et al. ( 2011 ) demonstrated that 2-methyl-pyran-4-one-3-o -b -d-glucopyranoside (mpg) isolated from pomegranate leaves, inhibited tnf a -induced cell adhesion molecules expression by blocking nuclear transcription factor-k b (nf-k b) translocation and activation. the results suggested that mpg could be useful as a novel lead molecule for developing future antiin fl ammatory agents. oral pomegranate extract decreased reactive oxygen species concentration and acute in fl ammation in the tympanic membrane in rats after myringotomy (kahya et al. 2011 ) . the density of in fl ammatory cells was signi fi cantly less in rats treated with the extract and the lamina propria thickness and vessel density were also signi fi cantly reduced. pretreatment of wistar rats with a methanolic extract of pomegranate peel followed by carbon tetrachloride treatment retained catalase, peroxidase, and superoxide dismutase to values comparable with control values, whereas lipid peroxidation was reduced by 54% as compared to control (chidambara murthy et al. 2002 ) . histopathological studies of the liver supported the hepatoprotective effects exhibited by the extract by restoring the normal hepatic architecture. kaur et al. ( 2006 ) demonstrated that pre-treatment of mice with pomegranate fl ower extract at a dose regimen of 50-150 mg/ kg body weight for a week signi fi cantly and dose dependently protected against ferric nitrilotriacetate (fe-nta)-induced oxidative stress as well as hepatic injury. the extract conferred up to 60% protection against hepatic lipid peroxidation and preserved glutathione (gsh) levels and activities of antioxidant enzymes viz., catalase (cat), glutathione peroxidase (gpx) glutathione reductase (gr) and glutathione-s-transferase (gst) by up to 36, 28.5, 28.7, 40.2 and 42.5% respectively. a protection against fe-nta induced liver injury was apparent as inhibition in the modulation of liver markers viz., aspartate aminotransferase (ast), alanine aminotransferase (alt), alkaline phosphatase (alp), bilirubin and albumin in serum. the histopathological changes produced by fe-nta, such as ballooning degeneration, fatty changes, necrosis were also alleviated by the extract. the fl ower extract was found to signi fi cantly scavenge superoxide radicals by up to 53.3%, hydrogen peroxide by up to 30%, hydroxyl radicals by up to 37% and nitric oxide by up to 74.5%. the extract also inhibited (.)oh induced oxidation of lipids and proteins in vitro. the potent antioxidant property of the fl ower extract was postulated to be responsible for its hepatoprotective effects. in another study, pomegranate fl ower infusion was found to exhibit hepatoprotective and antioxidant effect against trichloroacetic acid (tca)-exposed rats (celik et al. 2009 ) . the infusion signi fi cantly decreased levels of aspartate aminotransferase and alanine aminotransferase; increased signi fi cantly glutathione s-transferase activity in the liver, brain and spleen and maintained superoxide dismustase level in the liver. intake of pomegranate juice by mice for weeks was found to confer hepatic protection against protein and dna oxidation (faria et al. 2007 b ) . there was also a signi fi cant decrease in gsh (reduced glutathione) and gssg (oxidized glutathione), without change in the gsh/gssg ratio. all studied enzymatic activities (superoxide dismutase (sod), glutathione peroxidase (gpx), glutathione s-transferase (gst) and glutathione reductase (gr) and catalase) were found to be decreased by pomegranate juice treatment. also, glutathione s-transferase and glutathione synthetase transcription were also decreased in this group. chronic pomegranate peel extract administration to rats alleviated the bile duct ligation (bdl)-induced oxidative injury of the liver and improved the hepatic structure and function (toklu et al. 2007 ) . plasma antioxidant capacity and hepatic glutathione levels were signi fi cantly depressed by bdl but were increased back to control levels in the pomegranate extract-treated bdl group. increases in tissue malondialdehyde levels and myeloperoxidase activity due to bdl were reduced back to control levels by pomegranate extract treatment. similarly, increased hepatic collagen content in the bdl rats was reduced to the level of the control group with extract treatment. sumner et al. ( 2005 ) showed that daily consumption of pomegranate juice may improve stressinduced myocardial ischemia in patients who have coronary heart disease in a randomized, placebo-controlled, double-blind study. after 3 months, the extent of stress-induced ischemia decreased in the pomegranate group (sds − 0.8 ± 2.7) but increased in the control group (sds 1.2 ± 3.1). this bene fi t was observed without changes in cardiac medications, blood sugar, hemoglobin a1c, weight, or blood pressure in either group. mohan et al. ( 2010a ) demonstrated that pre-treatment of male wistar rats with pomegranate juice (100 and 300 mg/kg, p.o.) and its butanolic extract(100 mg/kg., p.o.) for a period of 21 days signi fi cantly inhibited the effects of isoproterenol-induced myocardial infarction such as heart rate, pressure rate index, ecg patterns, levels of lactate dehydrogenase, creatine kinase, superoxide dismutase and catalase in the serum and vascular reactivity changes. treatment with pj and b-pj (100 mg/kg., p.o.) alone did not alter any of the parameters as compared to vehicletreated wistar rats. hassanpour et al. ( 2011 ) found that pomegranate fruit extract displayed cardioprotective doxorubicin (dox)-induced cardiotoxicity in rats. rats administered the extract showed decreased qt and increase in heart rate compared to the dox group signi fi cant decrease in creatine kinase-mb isoenzyme, lactate dehydrogenase and no such signi fi cant decrease in aspartate aminotransferase were observed as compared to the dox group. there was signi fi cant increase in the level of reduced glutathione, whereas inhibition of lipid peroxidation and increase in superoxide dismutase concentration was not signi fi cant in the extract treated group compared to the dox group. histopathological study of the extract -treated group showed slight protection against myocardial toxicity induced by dox. p. granatum fruit peel extract elicited 100% precipitation of ovine haemoglobin in-vitro and when orally administered to ethanol-induced gastric-damaged rats produced a signi fi cant decrease in gastric lesions (gharzouli et al. 1999 ) . the acid content of the stomach was signi fi cantly increased by pomegranate (368%) suggesting that monomeric and polymeric polyphenols could strengthen the gastric mucosal barrier. administration of 70% methanolic pomegranate rind extract inhibited aspirin-and ethanol-induced gastric ulceration (ajaikumar et al. 2005 ) . treated animals showed increased antioxidant levels of superoxide dismutase (sod), catalase, glutathione (gsh) and glutathione peroxidase (gpx) and decreased level of tissue lipid peroxidation. no erosion of gastric mucosa, sub-mucosal edema and neutrophil in fi ltration was observed in treated animals. pomegranate tannins (500, 150, 50 mg/ kg) signi fi cantly inhibited ulcerative formation induced by both water immersion stress and pylorus ligation, and decreased the gastric mucosa damages induced by intragastric absolute ethanol, in dose-dependent manner in rats (lai et al. 2009 ) . its antiulcer effect was found to be due to increasing secretion of adherent mucus and free mucus from the stomach wall, which may inhibit generation of oxygen-derived free radicals, and decrease the consumption glutathione peroxidase (gsh-px) and superoxide dismutase (sod), decrease absolute alcohol-induced elevation of malondialdehyde and maintain content of no at normal level. punica granatum peel extract (ppe) supplementation of irradiated rats reduced oxidative damage in the ileal tissues and protected against ionizing radiation-induced enteritis and leukocyte apoptosis in rats, probably by a mechanism associated with the decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms (toklu et al. 2009 ) . ppe treatment reversed all these biochemical indices induced by irradiations such as the decrease in glutathione and total antioxidant capacity associated with increases in malondialdehyde levels, myeloperoxidase activity, collagen content of the tissue with a concomitant increase 8-hydroxy-2 ¢deoxyguanosine (an index of oxidative dna damage) and increases in pro-in fl ammatory cytokines (tnf-α, il-1β and il-6) and lactate dehydrogenase. histopathological alterations and the increase in leukocyte apoptosis and cell death induced by irradiation was also reversed by ppe. oral administration of aqueous methanolic extract of pomegranate (490 and 980 mg/kg bw) signi fi cantly reduced the ulcer lesion index produced by alcohol, indomethacin, and aspirin, at both doses in rats (alam et al. 2010 ) . in pylorusligated rats the extract signi fi cantly reduced the ulcer lesions, gastric volume, and total acidity and prevented the ulceration by increasing the ph and mucus secretion. oral administration of pomegranate extract and its ellagic acid rich fraction (100 and 200 mg/ kg) signi fi cantly attenuated dextran sulfate sodium -induced colonic in fl ammation in mice along with attenuation of histamine, myeloperoxidase and oxidative stress (singh et al. 2009 ) . the antiulcerative effect was comparable to sulphasalazine (100 mg/kg, p.o.) and sodium cromoglycate (40 mg/kg i.p). the authors stated that the antiulcerative effects may be attributed to mast cell stabilizing, antiin fl ammatory and antioxidant actions. pomegrante peel extracts exhibited remarkable in-vitro anti-helicobacter pylori activity against the clinical isolates of h. pylori (mean of inhibition zone diameter ranging from 16 to 40 mm/50 m g disc). helicobacter pylori infection causes lifelong chronic gastritis, which can lead to peptic ulcer, mucosa-associated lymphoid tissue (malt) lymphoma and gastric cancer. pretreatment of rats with hydroalcoholic extract of pomegranate fl owers (125 and 250 mg/kg p.o. twice daily for 3 days) signi fi cantly attenuated hypertonic glycerol-induced myoglobinuric renal dysfunction in a dose-dependent manner . the mechanism of renoprotective effects of punica granatum was found to involve activation of ppar-g and nitric oxide-dependent signalling pathway. pomegranate fruit rind powder at the dose of 100 mg/kg orally as aqueous suspension was found to stimulate the cell-mediated and humoral components of the immune system in rabbits (gracious ross et al. 2001 ) . the pomegranate powder elicited an increase in antibody titer to typhoid-h antigen. it also enhanced the inhibition of leucocyte migration in leucocyte migration inhibition test and induration of skin in delayed hypersensitivity test with puri fi ed protein derivative (ppd) con fi rming its stimulatory effect on cell-mediated immune response. punicalagin isolated from pomegranate fruit was found to be a potent immune suppressant, based on its inhibitory action on the activation of the nuclear factor of activated t cells (nfat). punicalagin downregulated the mrna and soluble protein expression of interleukin-2 from anti-cd3/anti-cd28-stimulated murine splenic cd4+ t cells and suppressed mixed leukocytes reaction (mlr) without exhibiting cytotoxicity to the cells. in vivo, the punicalagin treatment inhibited phorbol 12-myristate 13-acetate (pma)induced chronic ear edema in mice and decreased cd3+ t cell in fi ltration of the in fl amed tissue. the results suggested that punicalagin could be a potential candidate for the therapeutics of various immune pathologies. yamasaki et al. ( 2006 ) found that dietary pomegranate seed oil (pso) high in levels of punicic acid (9c, 11 t, 13c-octadecatrienoic acid), may enhance b-cell function in mice. splenocytes isolated from mice fed 0.12 or 1.2% pso produced larger amounts of immunoglobulins g and m but not immunoglobulin a irrespective of stimulation with or without phorbol 12-myristate 13-acetate and the calcium ionophore a23187. dietary pso did not affect the percentages of b cells or cd4-positive or cd8-positive t cells in splenocytes. a polysaccharide (psp001) isolated from pomegranate rind was found to have immunomodulatory activity (joseph et al. 2012 ) . psp001 showed in-vitro growth stimulatory effect on isolated normal lymphocytes, and a proliferative index of 1.21 at a concentration of 1,000 m g/-ml was obtained, indicating immunomodulatory activity. wistar rats with excision wounds treated with 5% water-soluble gel formulated from the methanolic extract of dried pomegranate rind, showed good complete wound healing after 10 days (chidambara murthy et al. 2004 ) . in comparison in rats treated with 2.5% gel, healing was observed on day 12, and in the positive control animals receiving the blank gel took 16-18 days for complete healing. collagen content in terms of hydroxyproline level increased by two-fold in the group treated with 5.0% gel. the gel extract was found to contain gallic acid and catechin as major components. aslam et al. ( 2006 ) found that pomegranate seed oil, but not aqueous extracts of fermented juice, peel or seed cake, stimulated human keratinocyte proliferation in monolayer culture. contrariwise, pomegranate peel aqueous extract (and to a lesser extent, both the fermented juice and seed cake extracts) stimulated type i procollagen synthesis and inhibited matrix metalloproteinase-1 (mmp-1; interstitial collagenase) production by dermal fi broblasts, but had no growth-supporting effect on keratinocytes. the results suggested that pomegranate peel aqueous extract could promote regeneration of dermis and pomegranate seed oil could promote regeneration of epidermis. pomegranate peel methanol extract-based ointment signi fi cantly enhanced wound contraction and the period of epithelialization as assessed by the mechanical (contraction rate, tensile strength), the biochemical (increasing of collagen, dna and proteins synthesis) and the histopathological characteristics in guinea pigs (hayouni et al. 2011 ) . the extract displayed antioxidant activity as potent as natural and synthetic compounds (trolox, butylated hydroxyanisole, quercetin). in addition, the extract exhibited signi fi cant antibacterial and antifungal activity against pseudomonas aeruginosa , staphylococcus aureus , escherichia coli , klebsiella pneumoniae , salmonella anatum , salmonella typhimurium , streptococcus pneumoniae , and fungi candida albicans , candida glabrata , trichopyton rubrum and aspergillus niger. the results suggested that the pomegranate formulated ointment may be used as skin repair agent without hazard to human health. the ethanol extract of p. granatum fl owers showed signi fi cant wound healing activity when topically administered in rats (pirbalouti et al. 2010 ) . the extract signi fi cantly increased the rate of wound contraction and collagen turnover. in-vitro studies using normal human epidermal keratinocytes, showed that pre-treatment with pomegranate fruit extract rich in anthocyannins and hydrolyzable tannins protected against the adverse effects of uv-b radiation by inhibiting uv-b-induced modulations of nuclear factor kappa b (nf-kappab) and mitogen-activated protein kinases (mapk) pathways (afaq et al. 2005a, b ) . similarly, they reported pomegranate fruit extract to be an effective agent for ameliorating uva-mediated skin damages by modulating cellular pathways in-vitro (syed et al. 2006 ) . uva-mediated cellular damage occurs primarily through the release of reactive oxygen species and is responsible for immunosuppression, photodermatoses, photoaging and photocarcinogenesis. pretreatment of normal human epidermal keratinocytes with the extract (60-100 m g/ ml) for 24 h before exposure to uva resulted in a dose-dependent inhibition of uva-mediated phosphorylation of signal transducers and activators of transcription 3 (stat3), protein kinase b/ akt and mitogen activated protein kinases (mapks) viz. extracellular signal-regulated kinase (erk1/2). the extract pretreatment also inhibited uva exposure-mediated increases in ki-67 antigen and pcna (proliferating cell nuclear antigen) and increased the cell-cycle arrest induced by uva in the g1 phase and the expression of bax and bad (proapoptotic proteins), while suppressing bcl-x(l) antiapoptotic protein expression. studies by zaid et al. ( 2007 ) showed that pretreatment of human immortalized hacat keratinocytes with polyphenol-rich pomegranate fruit extract inhibited uvb-mediated decrease in cell viability, decrease in intracellular glutathione content and increase in lipid peroxidation. immunoblot analysis showed that pretreatment of hacat cells with pomegranate fruit extract inhibited uvb-induced (1) upregulation of mmp-1, -2, -7 and -9, (2) decrease in timp-1, (3) phosphorylation of mapks and (iv) phosphorylation of c-jun, whereas no effect was observed on uvb-induced c-fos protein levels. the results suggested that pomegranate fruit protected hacat cells against uvb-induced oxidative stress and markers of photoaging and could be a useful supplement in skin care products. pomegranate fruit extract (5-60 mg/l) was effective at protecting human skin fi broblasts from cell death following uv irradiation (pacheco-palencia et al. 2008 ) . this photoprotective effect was postulated to be related to a reduced activation of the pro-in fl ammatory transcription factor nf-kappab, suppression of proapoptotic caspase-3, and an increased g0/g1 phase, associated with dna repair. higher polyphenolic concentrations (500-10,000 mg/l) were required to achieve a signi fi cant reduction in uv-induced reactive oxygen species levels and increased intracellular antioxidant capacity. pretreatment of reconstituted human skin "epiderm" with pomegranate-derived products pomx juice, pomx extract and pomegranate oil inhibited uvb-induced cyclobutane pyrimidine dimers (cpd), 8-dihydro-2 ¢deoxyguanosine (8-ohdg), protein oxidation and proliferating cell nuclear antigen (pcna) protein expression (afaq et al. 2009 ) . further, pretreatment of epiderm with pomegranate-derived products resulted in inhibition of uvb-induced collagenase (mmp-1), gelatinase (mmp-2, mmp-9), stromelysin (mmp-3), marilysin (mmp-7), elastase (mmp-12), and tropoelastin. mmp-2 and mmp-9 activities were also inhibited. overall, the results suggested that all three pomegranate-derived products may be useful against uvb-induced damage to human skin. park et al. ( 2010 ) using cultured human skin fi broblasts, demonstrated that pomegranate fruit rind extract rich in polyphenols catechin, quercetin, kaempferol, and equol signi fi cantly protected against uvb-induced skin damage. the synthesis of collagen was increased and the expression of mmp-1 was decreased. oral feeding of pomegranate fruit extract to mice provided substantial protection from the adverse effects of uvb radiation via modulation in early biomarkers of photocarcinogenesis (afaq et al. 2010 ) . the extract inhibited uvb-induced: skin edema; hyperplasia; in fi ltration of leukocytes; lipid peroxidation; hydrogen peroxide generation; ornithine decarboxylase (odc) activity; and odc, cyclooxygenase-2 and proliferating cell nuclear antigen protein expression. the extract enhanced repair of uvbmediated formation of cyclobutane pyrimidine dimers (cpds) and 8-oxo-7,8-dihydro-2 ¢deoxyguanosine (8-oxodg). the extract inhibited uvb-mediated nuclear translocation of nf-k b; activation of ikk a ; and phosphorylation and degradation of i k b a . additionally, the extract further enhanced uvb-mediated increase in tumour suppressor p53 and cyclin kinase inhibitor p21. in further studies, khan et al. ( 2012 ) reported that oral feeding of pomegranate fruit extract to skh-1 hairless mice inhibited uvbinduced epidermal hyperplasia, in fi ltration of leukocytes, protein oxidation and lipid peroxidation. immunoblot analysis demonstrated that oral feeding of pomegranate fruit extract to mice inhibited uvb-induced (1) nuclear translocation and phosphorylation of nuclear factor kappa b/p65, (2) phosphorylation and degradation of i k b a , (3) activation of ikk a / i k k b and (4) phosphorylation of mitogen-activated protein kinase proteins and c-jun. pomegranate fruit extract consumption also inhibited uvb-induced protein expression of (1) cox-2 and inos, (2) pcna and cyclin d1 and (3) matrix metalloproteinases-2,-3 and -9 in mouse skin. overall, the data showed that pomegranate fruit extract consumption afforded protection to mouse skin against the adverse effects of uvb radiation by modulating uvbinduced signalling pathways. in a double-blind, placebo-controlled trial involving female subjects age 20-40s, kasai et al. ( 2006 ) found that oral administration of an ellagic acid-rich pomegranate extract had an inhibitory effect on a slight pigmentation (stains and freckles, brightness of face) in the human skin caused by uv irradiation. methanolic pomegranate extract showed 53.4% invitro mushroom tyrosinase inhibitory activity (adhikari et al. 2008 ) . a pomegranate rind extract was found to have skin whitening activity (yoshimura et al. 2005 ) . the extract exhibited inhibitory activity against mushroom tyrosinase invitro comparable to that of the skin whitening agent, arbutin. when taken orally the extract inhibited uv-induced skin pigmentation on the back of brownish guinea pig. the results suggested the skinwhitening effect of the extract was probably due to inhibition of the proliferation of melanocytes and melanin synthesis by tyrosinase in melanocytes. a pomegranate polysaccharide fraction inhibited the formation of advanced glycation end-products (ages) by 28% and also inhibited the formation of fructosamine in the bsa/glucose system (rout and banerjee 2007 ) . the fraction inhibit 1,1-diphenyl-2-picrylhydrazyl (dpph) and 2,2 ¢ -azinobis[3ethylbenzothiazoline-6-sulfonate] abts(+) radical activities by 69 and 88%, respectively with 4 m g/ ml concentration it also inhibited mushroom tyrosinase by 43% at 10 m g/ml concentration suggesting its ef fi cacy as a potential skin whitener. pomegrante juice was shown to have a protective effect against ethylene glycol-induced nephrolithiasis in rats (tugcu et al. 2008 ) . ethylene glycol caused hyperoxaluria characterised by severe crystalization in renal tubules and granulovacuolar epithelial cell degeneration, marked elevation in malondialdehyde and nitric oxide levels and decrease of reduced glutathione (gsh) in rats there was no crystal formation in the rats treated with ethylene glycol and pomegranate juice. administration of pomegranate juice at medium and high dosage to rats was found to have inhibitory effects on renal tubular cell injury and oxidative stress caused by oxalate crystal deposition by reducing ros, inos, p38-mapk, and nf-kb expression (ilbey et al. 2009 ) . rats treated with methanol pomegranate seed extract exhibited signi fi cant inhibitory activity against castor-oil induced diarrhoea and pge2 induced enteropooling (das et al. 1999 ) . the extract also displayed a signi fi cant reduction in gastrointestinal motility in charcoal meal test in rats. pomegranate juice and polyphenol-rich pomegranate fruit extract reduced platelet aggregation, calcium mobilization, thromboxane a(2) production, and hydrogen peroxide formation, induced by collagen and arachidonic acid (mattiello et al. 2009 ) . the polyphenol -rich fruit extract was more potent in reducing platelet activation. studies showed that pomegranate fruit components (mainly ellagic acid) modulated human thrombin amidolytic activity (cuccioloni et al. 2009 ) . pomegranate fruit ethanol extract was found to signi fi cantly increase the growth of osteoblastic mc3t3-e1 cells and caused a signi fi cant elevation of alkaline phosphatase (alp) activity and collagen content in the cells (kim and choi 2009 ) . treatment the extract decreased the tnfα-induced production of interleukin il-6 and nitric oxide in osteoblasts. promprom et al. ( 2010 ) found pomegranate seed extract to be a potent stimulator of phasic activity in rat uterus. pomegranate seed extract and b -sitosterol, the main constituent of the extract (16%), increased spontaneous contractions of the rat uterus in a concentration-dependent manner. their data suggested that the uterotonic effect was due to nonestrogenic effects of b -sitosterol acting to inhibit k channels and sarcoplasmic reticulum calcium atpase and thereby increasing contraction via calcium entry on l-type calcium channels and myosin light chain kinase. two b -secretase (bace1) inhibitors (anti-dementia agents) were isolated from pomegranate rind and identi fi ed as ellagic acid and punicalagin with ic 50 values of 3.9 × 10 −6 and 4.1 × 10 −7 m (kwak et al. 2005 ) . ellagic acid and punicalagin were less inhibitory to α-secretase (tace) and other serine proteases such as chymotrypsin, trypsin, and elastase, thus indicating that they were relatively speci fi c inhibitors of bace1. b -secretase is an aspartic-acid protease involved in the pathogenesis of alzheimer's disease studies showed that ethanolic extract of p. granatum seeds signi fi cantly exhibited the anxiolytic activity animal models of elevated plus maze test, barbiturate-induced sleeping time, tail suspension test, hot-plate and tail-fl ick tests (kumar et al. 2008 ) . the extract (250 and 500 mg/kg) signi fi cantly increased the sleeping latency and reduced the sleeping time. tail suspension test showed that the extract (250 and 500 mg/kg) was able to induce a signi fi cant decrease in the immobility time, similar to imipramine, a recognized antidepressant drug. tail-fl ick and hot-plate tests exhibited antinociceptive property of pomegranate extract, similar to morphine, a recognized antinociceptive agent. phytochemical screening and measurement of reducing power revealed the central nervous system (cns) activity of ethanol extract of pomegranate seeds may be due to its antioxidative pro fi le. supplementation of pomegranate fl owers led to improvements in learning and memory performances of streptozotocin-induced diabetic rats (cambay et al. 2011 ) . supplementation of pomegranate fl owers restored the elevated levels of lipid peroxidation and decreased level of glutathione towards their control values. daily pomegranate fl ower supplementation to diabetic rats reduced the increase in glial-fi brilar acidic protein (gfap) contents induced by diabetes in the hippocampus. the observations suggested that pomegranate fl ower supplementation decreased oxidative stress and amelioratedimpairment in learning and memory performances in diabetic rats and may be clinically useful in treating neuronal de fi cit in diabetic patients. loren et al. ( 2005 ) found that maternal dietary supplementation with pomegranate juice was neuroprotective in an animal model of neonatal hypoxic-ischemic brain injury. dietary supplementation with pomegranate juice resulted in markedly decreased brain tissue loss (>60%) in all three brain regions assessed, with the highest pomegranate juice dose having greatest signi fi cance pomegranate juice also diminished caspase-3 activation by 84% in the hippocampus and 64% in the cortex. in further studies, the scientists showed that pomegranate polyphenols and resveratrol reduced caspase-3 activation following neonatal hypoxic-ischemic injury (west et al. 2007 ) . in separate study, transgenic mice (app(sw)/tg2576) treated with pomegranate juice had signi fi cantly less (approximately 50%) accumulation of soluble aβ42 and amyloid deposition in the hippocampus as compared to control mice (hartman et al. 2006 ) . mice administered pomegranate juice learned water maze tasks more quickly and swam faster than controls. the results suggest that pomegranate juice may be useful in alzheimer's disease and warrant further studies. choi et al. ( 2011 b ) found that the ethanol pomegranate extract mitigated h 2 o 2induced oxidative stress in pc12 cells. additionally, the extract inhibited neuronal cell death caused by a b -induced oxidative stress and a b -induced learning and memory de fi ciency in mice. studies showed that pomegranate fruit extract exhibited embryo protective effect against adriamycin-induced oxidative stress in chick embryos (kishore et al. 2009 ) . pre-administration of pomegranate fruit extract signi fi cantly ameliorated to normal, embryo gross morphological deformities and signi fi cant changes in the levels of biochemical parameters in amniotic fl uid observed in the adriamycin-treated group. pomegranate juice consumption by healthy male rats provided an increase in epididymal sperm concentration, sperm motility, spermatogenic cell density and diameter of seminiferous tubules and germinal cell layer thickness and antioxidant activity, and it decreased abnormal sperm rate when compared to the control group (türk et al. 2008 ) . a signi fi cant decrease in malondialdehyde level and marked increases in glutathione, glutathione peroxidase and catalase activities, and vitamin c level were observed in rats treated with different doses of pomegranate juice. studies showed that ethanolic extract of pomegranate could be useful for the treatment of the deleterious effect of lead acetate administration on sperm production in rats (leiva et al. 2011 ) . the extract exhibited antioxidant activity similar to that of ascorbic acid and prevented lead acetate -induced spermatogenic disruption in rats. its antioxidant activity could explain its capacity to reverse the damage produced by lead acetate on spermatogenesis. in a randomized, placebo-controlled, doubleblind, crossover study involving male patients with mild to moderate erectile dysfunction, of the 42 subjects who demonstrated improvement in global assessment questionnaires (gaq) scores after beverage consumption, 25 reported improvement in erectile function after drinking pomegranate juice (forest et al. 2007 ) . subjects were more likely to have improved scores when pomegranate juice was consumed. although overall statistical signi fi cance was not achieved, this pilot study suggested the possibility that larger cohorts and longer treatment periods may achieve statistical signi fi cance. studies in rabbits with atherosclerosis-induced erectile dysfunction showed that pomegranate extract signi fi cantly improved intracavernosal blood fl ow, erectile activity, smooth muscle relaxation and fi brosis of the atherosclerotic group in comparison with the atherosclerotic group receiving placebo, but did not normalize them to the agematched control levels . pomegranate extract appeared more effective in diminishing oxidative products, preventing superoxide dismutase and aldose reductase gene upregulation, and protecting mitochondrial, endothelial and caveolae structural integrity of the atherosclerotic group. the study showed that dietary antioxidants could improve arteriogenic erectile dysfunction. pomegranate known to contain estrogens (estradiol, estrone, and estriol) exhibited estrogenic activities in mice (mori-okamoto et al. 2004 ) . administration of pomegranate extract (juice and seed extract) for 2 weeks to ovariectomized mice prevented the loss of uterus weight and shortened the immobility time compared with 5% glucose-dosed mice (control). further, ovariectomy-induced decrease of bone mineral density was normalized by administration of the pomegranate extract. the bone volume and the trabecular number were signi fi cantly increased and the trabecular separation was decreased in the pomegranate-dosed group compared with the control group. some histological bone formation/ resorption parameters were signi fi cantly increased by ovariectomy but were normalized by administration of the pomegranate extract. these changes suggested that the pomegranate extract inhibited ovariectomy-stimulated bone turnover. the authors concluded that pomegranate may be clinically effective on a depressive state and bone loss in menopausal syndrome in women. studies in human volunteers, found that in human liver microsomes, the mean 50% inhibitory concentrations (ic 50 ) for pomegranate juice (pj) and grapefruit juice (gfj) versus cyp3a (triazolam α-hydroxylation) were 0.61 and 0.55%, (v/v) respectively without preincubation of inhibitor with microsomes (farkas et al. 2007 ) . after preincubation, the ic 50 for pj increased to 0.97% whereas the ic 50 for gfj decreased to 0.41% suggesting mechanism-based inhibition by gfj but not pj. administration of pj also did not affect c(max), total area under the curve (auc), or clearance of oral midazolam. however, gfj increased midazolam c(max) and auc by a factor of 1.3 and 1.5, respectively, and reduced oral clearance to 72% of control values. the results suggested pj did not alter clearance of intravenous or oral midazolam, whereas gfj impaired clearance and elevated plasma levels of oral midazolam. jarvis et al. ( 2010 ) reported a potential interaction between pomegranate juice and warfarin as laboratory studies hade shown that pomegranate juice inhibited cytochrome p450 enzymes involved in warfarin metabolism. in a an open-label, randomized, single-center, two-period crossover study in healthy japanese volunteers, a single subtherapeutic doses of midazolam following 2 weeks consumption of pomegranate juice did not signi fi cantly alter the pharmacokinetic pro fi le of midazolam compared with that of the control (misaka et al. 2011 ) . results of a 5-week randomized, double-blind, placebo-controlled study involving 30 patients suggested that polyphenol-rich pomegranate juice (pj) supplementation added no bene fi t to the current standard therapy in patients with stable chronic obstructive pulmonary disease (cerdá et al. 2006 ) . the high teac (trolox equivalent antioxidant capacity) of pj could not be extrapolated in-vivo probably due to the metabolism of its polyphenols by colonic micro fl ora. the understanding of the different bioavailability of dietary polyphenols was thus critical before claiming any antioxidant-related health bene fi t. elbow fl exion strength was signi fi cantly higher during the 2-to 168-h period post-exercise with pomegranate juice compared with that of placebo (trombold et al. 2011 ) . elbow fl exor muscle soreness was also signi fi cantly reduced with pomegranate juice compared with that of placebo and at 48 and 72 h post-exercise. isometric strength and muscle soreness in the knee extensors were not signi fi cantly different with pomegranate juice compared with those using placebo. the results indicated a mild, acute ergogenic effect of pomegranate juice in the elbow fl exor muscles of resistance trained individuals after eccentric exercise. seven highly active ellagitannin inhibitors against carbonic anhydrase, punicalin (2), punicalagin (3), granatin b (5), gallagyldilactone (7), casuarinin (8), pedunculagin (9) and tellimagrandin i (10), and four weakly active ellagitannin inhibitors, gallic acid (1), granatin a (4), corilagin (6) and ellagic acid (11), were isolated from pomegranate pericarps (satomi et al. 1993 ) . the type of inhibition by compounds (3) and (7) using p -nitrophenyl acetate as a substrate, was noncompetitive. carbonic anhydrase inhibitors are used as antiglaucoma drugs, and many potent carbonic anhydrase inhibitors have also been shown to inhibit the growth of several tumour cell lines in-vitro and in-vivo providing interesting leads for developing novel antitumour therapies (supuran et al. 2004 ) using the hot plate method in mice, pomegranate fl ower extracts showed signi fi cant analgesic activity at a dose of 50 mg/kg body weight (chakraborthy 2008 ) . maximum analgesic activity was observed at 60 min after drug administration, which was equivalent to the standard drug used morphine sulphate. two milliliters of aqueous extract of pomegranate roots exhibited higher activity on cultures from entamoeba histolytica than from entamoeba invadens strains, producing growth inhibitions of about 100 and 40% respectively (segura et al. 1990 ) . alkaloid concentrations of 1 mg/ml had no amoebicide activity, however tannins at concentrations of 10 m g/ml for e. histolytica , and 100 m g/ml for e. invadens were suf fi cient to produce an growth inhibition about 100%. tannic acid was also tested on the cultures of e. histolytica producing a high inhibitory activity on growth, this effect was produced at 0.01 mg/ ml similar to that observed with the tannin mixture. the methanolic extract of pomegranate was reported to in-vitro inhibit the growth of the malarial parasite, plasmodium berghei (dell'agli et al. 2009 ) . in another study, gallagic acid and punicalagin from pomegranate by-product exhibited antiplasmodial activity against plasmodium falciparum d6 and w2 clones with ic 50 values of 10.9, 10.6, 7.5 and 8.8 m m, respectively (reddy et al. 2007 ) . pomegranate extract exhibited strong antimalarial activity against plasmodium falciparum (valdés et al. 2010 ) . p. grantum plant extract also exhibited in-vitro activity against the vaginal parasite, trichomonas vaginalis (el-sherbini et al. 2009 ) . hydroalcoholic pomegranate extract inhibited the growth of intracellular amastigotes of leishmania amazonensis with ic 50 value of 69.6 m g/ml (garcía et al. 2010 ) . additionally, a low toxicity on macrophage from balb/c mice was observed. wibaut and hollstein ( 1957 ) found that the anthelminthic activity of pomegranate bark extract was mainly due to isopelletierine, methylisopelletierine while y pelleterine was less active the molluscicidal activity of p. granatum bark and canna indica root against the snail, lymnaea acuminata was found to be both time and dose dependent (tripathi and singh 2000 ) . the toxicity of p. granatum bark was more pronounced than that of c. indica . the 24 h lc 50 of the c. indica was 6.54 mg/l whereas that of the bark of p. granatum was 4.39 mg/l. the ethanol extract of p. granatum (24 h lc 50 : 22.42 mg/l) was more effective than the ethanol extract of c. indica (24 h lc 50 : 55.65 mg/l) in killing the test animals. p. granatum and c. indica may be used as potent molluscicides since the concentrations used to kill the snails were not toxic to the fi sh colisa fasciatus , sharing the same habitat with the snail. in a subsequent study, tripathi et al. ( 2004 ) reported that sub-lethal 24 h exposure to active fraction of pomegranate bark separately or in combination with canna roots signi fi cantly inhibited the activity of acetylcholinesterase, acid/alkaline phosphatase, na(+)k(+)atpase and lactic dehydrogenase in the nervous tissue of lymnaea acuminata. lei et al. ( 2003 ) found that ellagic acid, the principal bioactive component of pomegranate leaf extract, had poor absorption and rapid elimination after oral administration pomegranate leaf extract, and part of it was absorbed from stomach. studies in rats showed that only 3-6% of the ingested punicalagin was detected as such or as metabolites in urine and faeces (cerdá et al. 2003b ) . only traces of punicalagin metabolites being detected in liver or kidney. the transformation of ellagic acid derivatives to 6h-dibenzo[b,d] pyran-6-one derivatives in the rat was con fi rmed. studies of cerdá et al. ( 2004 ) found that the potential systemic biological effects of pomegranate juice ingestion should be attributed to the colonic micro fl ora metabolites rather than to the polyphenols present in the juice. neither the potent antioxidant punicalagin nor ellagic acid present in pomegranate juice were detected in both plasma and urine on ingestion of pomegranate juice. three microbial ellagitannin-derived metabolites were detected: 3,8-dihydroxy-6h-dibenzo[b,d]pyran-6-one glucuronide, an unidenti fi ed aglycone (tentatively, trihydroxy-6h-dibenzo[b,d]pyran-6-one) and hydroxy-6-hdibenzo [b,d] pyran-6-one glucuronide in the plasma and urine. the metabolites did not show signi fi cant antioxidant activity compared to punicalagin from pomegranate juice. in separate studies, ellagic acid was detected in human plasma at a maximum concentration (31.9 ng/ml) after 1 h post-ingestion of pomegranate juice but was rapidly eliminated by 4 h (seeram et al. 2004 ) . six hours post-ingestion of pomegranate juice, ellagic acid (ea) was detected in plasma of all healthy human volunteers with a maximum concentration of 0.06 m mol/l, area under concentration time curve of 0.17 ( m mol × h) × l(-1), time of maximum concentration of 0.98 h, and elimination half-life of 0.71 h . ellagic acid metabolites, including dimethylellagic acid glucuronide (dmeag) and hydroxy-6h-benzopyran-6-one derivatives (urolithins), were also detected in plasma and urine in conjugated and free forms. dmeag was found in the urine obtained from 15 of 18 subjects on day 0, but was not detected on d −1 (day before) or +1 (day after), demonstrating its potential as a biomarker of intake. urolithin a-glucuronide was found in urine samples from 11 subjects on d 0 and in the urine from 16 subjects on d +1. urolithin b-glucuronide was found in the urine of three subjects on d 0 and in the urine of fi ve subjects on d+1. the scientists asserted that urolithins, formed by intestinal bacteria, may contribute to the biological effects of pomegranate juice as they may persist in plasma and tissues and account for some of the health bene fi ts noted after chronic juice consumption. studies by seeram et al. ( 2008 ) found that pomegranate juice, pomegranate polyphenol liquid extract and pomegranate polyphenol powder extract provide similar levels of plasma and urinary ellagitannin metabolites such as urolithin a, in human subjects. there was a delay in time of maximum concentration of pomegranate powder extract compared to pomegranate juice and pomegranate polyphenol liquid. mertens-talcott et al. ( 2006 ) found ellagic acid from pomegranate extract to be bioavailable at 1 h after consumption by healthy volunteers. its metabolites urolithin a, urolithin b, hydroxyl-urolithin a, urolithin a-glucuronide, and dimethyl ellagic acidglucuronide were found in the plasma. the antioxidant capacity measured with the oxygen radical absorbance capacity (orac) assay was increased with a maximum effect of 32% after 0.5 h, whereas the generation of reactive oxygen species (ros) was not affected. vidal et al. ( 2003 ) found that in chick embryo model doses of hydroalcoholic pomegranate fruit extract of less than 0.1 mg per embryo were not toxic. the ld 50 of the extract, determined in of-1 mice of both sexes after intraperitoneal administration, was 731 mg/kg. con fi dence limits were 565-945 mg/kg. at the doses of 0.4 and 1.2 mg/kg of extract, the repeated intranasal administration to wistar rats produced no toxic effects in terms of food intake, weight gain, behavioural or biochemical parameters, or results of histopathological studies. cerdá et al. ( 2003a ) found that repeated oral administration of high doses of the pomegranate ellagitannin punicalagin to rats for 37 days was not toxic. punicalagin and related metabolites were identi fi ed in plasma, liver, and kidney. five punicalagin-related metabolites were detected in liver and kidney, that is, two ellagic acid derivatives, gallagic acid, 3,8-dihydroxy-6h-dibenzo [b,d] pyran-6-one glucuronide, and 3,8,10-trihydroxy-6h-dibenzo [b,d] pyran-6-one. feedstuff intake, food utility index, and growth rate were lower in punicalagin treated rats during the fi rst 15 days without signi fi cant adverse effects, which could be due to the lower nutritional value of the punicalagin-enriched diet together with a decrease in its palatability (lower food intake). no signi fi cant differences were found in punicalagin treated rats in any blood parameter analyzed (including the antioxidant enzymes glutathione peroxidase and superoxide dismutase) with the exception of urea and triglycerides, which remained at low values throughout the study. clinical studies by heber et al. ( 2007 ) demonstrated the safety of a pomegranate ellagitannin-enriched polyphenol dietary supplement in overweight individuals with increased waist size and provided evidence of antioxidant activity in humans re fl ected by a signi fi cant reduction in thiobarbituric acid reactive substances (tbars) linked with cardiovascular disease risk. patel et al. ( 2008 ) found that the no observed-adverse-effect level (noael) for a standardized pomegranate fruit extract was determined as 600 mg/kg body weight/day, the highest dose tested in rats. compared to the control group, administration of the extract did not result in any toxicologically signi fi cant treatmentrelated changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, clinical pathology evaluations and organ weights. toxicological evaluation of pomegranate seed oil (pso) showed that the no observable adverse effect level (noael) was 50,000 ppm pso (=4.3 g pso/kg body weight/day) (meerts et al. 2009 ) . no mutagenicity of pso was observed in the absence and presence of metabolic activation up to precipitating concentrations of 5,000 m g/ plate (ames test) or 333 m g/ml (chromosome aberration test). the acute oral toxicity study revealed no signi fi cant fi ndings at 2,000 mg pso/ kg body weight. results from reversion and gene-conversion test in microorganisms, sister chromatid exchanges, micronuclei and sperm-shape abnormality assays in mice, clearly showed that the hydroalcoholic extract of pomegranate whole fruit was genotoxic when tested both in-vitro and in-vivo (sánchez-lamar et al. 2008 ) . the bark of the roots, the fl owers, the rind of pomegranate fruit and the seeds, are of fi cial in many pharmacopoeias. various parts of the pomegranate plant have been extensively used for thousands of years in traditional medicine in the middle east, ancient greece and asia (burkill 1966 ; grieve 1971 ; stuart 2012 ) ; and in india such as in the ayurveda and unani systems of medicine (nadkarni and nadkarni. 1982 ; sharma et al. 2002 ; kapoor 2000 ; pradeep et al. 2008 ) . the fruit rind and stem bark have been used as a traditional remedy for diarrhoea, dysentery and intestinal parasites. pomegranate pericarp has been commonly employed as a crude drug in indian traditional medicine for the treatment of diarrhoea as well as for use as an astringent, antihelminthic, asphrodisacs, laxative, diuretic, stomachic, cardiotonic and refrigerant. the seeds and juice are considered as bitter and astringent and employed as a tonic for hear and throat ailments. the astringent qualities of the fl ower sap, fruit rind and tree bark are considered useful remedies for nose bleeds and gum bleeds, toning skin, (after mixing with mustard oil) fi rming-up sagging breasts and treating haemorrhoids. a syrup prepared from the fruit is useful in all bilious complaints. the juice of the fresh fruit is much esteemed in dyspepsia and as a cooling, thirst-quenching beverage in fever and sickness. the fruit juice is also found bene fi cial in leprosy. pomegranate fruit juice has been used as eyedrops to treat cataracts. dried, pulverized fl ower buds are employed as a remedy for bronchitis. pomegranate has been reported as a remedy for diabetes in the unani system of medicine practiced in the middle east and india. the ancient greeks and egyptians used the fruit rind, fl owers and root bark as astringents and the last as vermicide for treating tapeworms. in malaysia, the root bark is used as vermifuge and powdered root bark is administered to children for stomach pains. the root is also used for diarrhoea and tits sap used for treating sore-eyes. leaves are used in jamu preparations with a raft of other herbal ingredients for many medicinal complaints. pounded leaves are used in a complex bolus for stomach ache and the fruit juice is recommended for coughs. in singapore, the root bark has been used in as a component in a compound infusion or decoction taken by women for 40 days after childbirth. other traditional uses of the fruit rind and root include as a treatment for snakebite (jain and puri 1984 ) , diabetes (singh 1986 ) , burns (siang 1983 ) , leprosy and assorted gynecological problems (singh et al. 1980 ) . in sri lanka, the fresh fruit has been used as a refrigerant to lower fever (arseculeratne et al. 1985 ) . in the philippines, a decoction of the tender leaves is used as a gargle for affections of the buccal cavity. the rind of the fruit is used internally in decoction as anthelmintic and taenifuge. in mexico, a decoction of the fl owers is gargled to relieve oral and throat in fl ammation. in korea, traditional uses of the fruit and rind include as an anthelminthic and for phlegm, cholethiasis, tineapedis and laryngitis. punica granatum is a drought tolerant tree suitable for arid and semi-arid zone afforestation. pomegranate has deep rooting system and is used for erosion control, planted along rivers to stabilize banks. an ideal suitable ornamental plant for gardens and amenity parks. pomegranate grows along well as intercrop with grapes in mediterranean countries. the tree is sometimes used for fencing and planted as boundary plants. pomegranate leaf litter decomposes slowly and is suitable for mulching. the leaves are foraged by domesticated stock. ink can be made by steeping the leaves in vinegar. both the fruit rind and the fl owers yield dyes for textiles. the light-coloured wood is hard and durable, mostly used in making farm implements, walking-sticks and in woodcrafts as it is only available in small dimension. tree branches are used as fi rewood. the bark is used in tanning and dyeing providing the yellow hue for moroccan leather. root bark yields a black ink rich in tannins. in japan, an insecticide is derived from the bark. studies revealed that pomegranate peel can prepared as an adsorbent in treating industrial ef fl uents containing phenols and safely disposed of by stabilizing into cement (bhatnagar and minocha 2009 ) . studies showed that that pomegranate peel waste can be used as adsorbent bene fi cially for nickel removal from aqueous solution (bhatnagar and minocha 2010 ) . pomegranate husk when converted into activated carbon exhibited its ability to remove hexavalent chromium from wastewater (nemr 2009 ) . studies showed that the nutritive value and the antioxidant capacity of pomegranate peel could be enhanced by ensiling into a favorable healthpromoting constituent of feedlot beef cattle diet (shabtay et al. 2008 ) . dietary supplementation with fresh peels promoted signi fi cant increases in feed intake and a-tocopherol concentration in the plasma, with positive tendency toward increased weight gain of bull calves. the pomegranate fruit is steeped in religious and cultural signi fi cance in judaism, christianity, islam, hinduism religions, persian, armenian, azerbaijani and chinese cultures (wikipedia 2012 ) . pomegrante germinates readily from seeds and are established from seedlings, rooted hardwood cuttings, from air layering and suckers. screening of nepalese crude drugs traditionally used to treat hyperpigmentation: in vitro tyrosinase inhibition pomegranate fruit extract modulates uv-bmediated phosphorylation of mitogen-activated protein kinases and activation of nuclear factor kappa b in normal human epidermal keratinocytes paragraph sign anthocyanin-and hydrolyzable tannin-rich pomegranate fruit extract modulates mapk and nf-kappab pathways and inhibits skin tumorigenesis in cd-1 mice protective effect of pomegranate-derived products on uvb-mediated damage in human reconstituted skin oral feeding of pomegranate fruit extract inhibits early biomarkers of uvb radiation-induced carcinogenesis in skh-1 hairless mouse epidermis short communication: studies on punica granatum -i isolation and identi fi cation of some constituents from the seeds of punica granatum punica granatum l. extract inhibits il-1beta-induced expression of matrix metalloproteinases by inhibiting the activation of map kinases and nf-kappab in human chondrocytes in vitro the inhibition of gastric mucosal injury by punica granatum l. (pomegranate) methanolic extract protective effects of punica granatum in experimentally-induced gastric ulcers pomegranate extracts potently suppress proliferation, xenograft growth, and invasion of human prostate cancer cells anthocyanins characterization of 15 iranian pomegranate ( punica granatum l.) varieties and their variation after cold storage and pasteurization antimicrobial activity of pomegranate ( punica granatum l.) fruit peels studies on medicinal plants of sri lanka. part 14 pomegranate as a cosmeceutical source: pomegranate fractions promote proliferation and procollagen synthesis and inhibit matrix metalloproteinase-1 production in human skin cells pomegranate juice consumption inhibits serum angiotensin converting enzyme activity and reduces systolic blood pressure pomegranate juice consumption reduces oxidative stress, atherogenic modi fi cations to ldl, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein e-de fi cient mice pomegranate juice fl avonoids inhibit low-density lipoprotein oxidation and cardiovascular diseases: studies in atherosclerotic mice and in humans pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and ldl oxidation pomegranate phenolics from the peels, arils, and fl owers are antiatherogenic: studies in vivo in atherosclerotic apolipoprotein e-de fi cient (e 0) mice and in vitro in cultured macrophages and lipoproteins an aqueous pomegranate peel extract inhibits neutrophil myeloperoxidase in vitro and attenuates lung in fl ammation in mice flora of java (spermatophytes only), 1. noordhoff melatonin, serotonin, and tryptamine in some egyptian food and medicinal plants antidiabetic effect of punica granatum fl owers: effect on hyperlipidemia, pancreatic cells lipid peroxidation and antioxidant enzymes in experimental diabetes new sterol esters from the fl owers of punica granatum linn consumption of pomegranate decreases serum oxidative stress and reduces disease activity in patients with active rheumatoid arthritis: a pilot study 2-methyl-pyran-4-one-3-o -b -d-glucopyranoside isolated from leaves of punica granatum inhibits the tnf a -induced cell adhesion molecules expression by blocking nuclear transcription factor-k b (nf-k b) the antiplaque ef fi cacy of pomegranate mouthrinse adsorptive removal of 2,4-dichlorophenol from water utilizing punica granatum peel waste and stabilization with cement biosorption optimization of nickel removal from water using punica granatum peel waste urolithins, intestinal microbial metabolites of pomegranate ellagitannins, exhibit potent antioxidant activity in a cell-based assay the effect of pomegranate ( punica granatum l.) byproducts and ellagitannins on the growth of human gut bacteria pomegranate-mediated chemoprevention of experimental hepatocarcinogenesis involves nrf2-regulated antioxidant mechanisms climate effects on anthocyanin accumulation and composition in the pomegranate ( punica granatum l.) fruit arils synergic interaction between pomegranate extract and antibiotics against staphylococcus aureus pomegranate extract inhibits staphylococcus aureus growth and subsequent enterotoxin production a dictionary of the economic products of the malay peninsula, revised reprint, 2 vols. ministry of agriculture and co-operatives characterization of a potential nutraceutical ingredient: pomegranate ( punica granatum l.) seed oil unsaponi fi able fraction volatile composition and sensory quality of spanish pomegranates ( punica granatum l.) pomegranate ( punica granatum l.) fl ower improves learning and memory performances impaired by diabetes mellitus in rats hepatoprotective role and antioxidant capacity of pomegranate ( punica granatum ) fl owers infusion against trichloroacetic acidexposed in rats repeated oral administration of high doses of the pomegranate ellagitannin punicalagin to rats for 37 days is not toxic evaluation of the bioavailability and metabolism in the rat of punicalagin, an antioxidant polyphenol from pomegranate juice the potent in vitro antioxidant ellagitannins from pomegranate juice are metabolised into bioavailable but poor antioxidant hydroxy-6h-dibenzopyran-6-one derivatives by the colonic micro fl ora of healthy humans pomegranate juice supplementation in chronic obstructive pulmonary disease: a 5-week randomized, doubleblind, placebo-controlled trial analgesic activity of various extracts of punica granatum (linn) fl owers antibacterial activity of thai medicinal plant extracts on the skin infectious microorganisms flavonoid diglycoside from punica granatum studies on antioxidant activity of pomegranate ( punica granatum ) peel extract using in vivo models study on wound healing activity of punica granatum peel the partition chromatography of alkaloids: part iii.-the alkaloids of punica granatum in vitro and in vivo antibacterial activity of punica granatum peel ethanol extract against salmonella punica granatum protects against oxidative stress in pc12 cells and oxidative stress-induced alzheimer's symptoms in mice the wealth of india: a dictionary of indian raw materials and industrial products pomegranate extract inhibits the proliferation and viability of mmtv-wnt-1 mouse mammary cancer stem cells in vitro studies on antidiarrhoeal activity of punica granatum seed extract in rats studies on the hypoglycaemic activity of punica granatum seed in streptozotocin induced diabetic rats effects of consumption of pomegranate juice on carotid intima-media thickness in men and women at moderate risk for coronary heart disease bene fi cial effects of pomegranate juice on oxidation-sensitive genes and endothelial nitric oxide synthase activity at sites of perturbed shear stress pomegranate juice reduces oxidized low-density lipoprotein downregulation of endothelial nitric oxide synthase in human coronary endothelial cells the in fl uence of pomegranate fruit extract in comparison to regular pomegranate juice and seed oil on nitric oxide and arterial function in obese zucker rats effects of a pomegranate fruit extract rich in punicalagin on oxidation-sensitive genes and enos activity at sites of perturbed shear stress and atherogenesis quantitative analysis of fl avan-3-ols in spanish foodstuffs and beverages antiplasmodial activity of punica granatum l. fruit rind the antioxidant potency of punica granatum l. fruit peel reduces cell proliferation and induces apoptosis on breast cancer pomegranate extract mouth rinsing effects on saliva measures relevant to gingivitis risk antimicrobial activity of six pomegranate ( punica granatum l.) varieties and their relation to some of their pomological and phytonutrient characteristics elemental and nutritional analysis of punica granatum from turkey analysis of organic acids in fruit juices by liquid chromatography-mass spectrometry: an enhanced tool for authenticity testing pomegranate ( punica granatum ) juices: chemical composition, micronutrient cations, and antioxidant capacity physico-chemical properties and dpph-abts scavenging activity of some local pomegranate ( punica granatum ) ecotypes antioxidant capacities of phenolic compounds and tocopherols from tunisian pomegranate ( punica granatum ) fruits fatty acids from tunisian and chinese pomegranate ( punica granatum l.) seeds chemical composition of juice and seeds of pomegranate fruit studies on pomegranate seed oil ef fi cacy of two plant extracts against vaginal trichomoniasis two ellagitannins from punica granatum heartwood two new ellagic acid rhamnosides from punica granatum heartwood ellagiand gallotannins from punica granatum heartwood concentrated pomegranate juice improves lipid pro fi les in diabetic patients with hyperlipidemia cholesterol-lowering effect of concentrated pomegranate juice consumption in type ii diabetic patients with hyperlipidemia pomegranate juice effects on cytochrome p450s expression: in vivo studies effect of pomegranate ( punica granatum ) juice intake on hepatic oxidative stress pomegranate juice does not impair clearance of oral or intravenous midazolam, a probe for cytochrome p450-3a activity: comparison with grapefruit juice monoacylglycerol from punica granatum seed oil effect of probiotication on antioxidant and antibacterial activities of pomegranate juices from sour and sweet cultivars determination of lignans in edible and nonedible parts of pomegranate ( punica granatum l.) and products derived there from, particularly focusing on the quantitation of isolariciresinol using hplc-dad-esi/ms(n) ef fi cacy and safety of pomegranate juice on improvement of erectile dysfunction in male patients with mild to moderate erectile dysfunction: a randomized, placebo-controlled, double-blind, crossover study foundation for revitalisation of local health traditions pomegranate and cardiovascular diseases: pomegranate juice polyphenolic antioxidants protect against oxidative stress and atherosclerosis development pomegranate juice inhibits oxidized ldl uptake and cholesterol biosynthesis in macrophages pomegranate juice polyphenols increase recombinant paraoxonase-1 binding to high-density lipoprotein: studies in vitro and in diabetic patients screening of medicinal plants against leishmania amazonensis synergistic growth inhibition of mouse skin tumors by pomegranate fruit extract and diallyl sul fi de: evidence for inhibition of activated mapks/nf-k b and reduced cell proliferation effects of aqueous extracts from quercus ilex l. root bark, punica granatum l. fruit peel and artemisia herba-alba asso leaves on ethanolinduced gastric damage in rats arte's f, toma's-barbera'n f (1995) changes in pomegranate juice pigmentation during ripening antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing effect of pomegranate juice on insulin secretion and sensitivity in patients with obesity dissimilar in vitro and in vivo effects of ellagic acid and its microbiota-derived metabolites, urolithins, on the cytochrome p450 1a1 anti-microbial activities of pomegranate rind extracts: enhancement by cupric sulphate against clinical isolates of s. aureus , mrsa and pvl positive ca-mssa total phenolic distribution of juice, peel, and seed extracts of four pomegranate cultivars immunomodulatory activity of punica granatum in rabbits -a preliminary study punicic acid is an omega-5 fatty acid capable of inhibiting breast cancer proliferation antioxidant activities of peel, pulp and seed fractions of common fruits as determined by frap assay evaluation of antioxidant activity and preventing dna damage effect of pomegranate extracts by chemiluminescence method pomegranate juice is potentially better than apple juice in improving antioxidant function in elderly subjects pomegranin, an antifungal peptide from pomegranate peels pomegranate ( punica granatum ) puri fi ed polyphenol extract inhibits in fl uenza virus and has a synergistic effect with oseltamivir in vitro antibacterial activity of some iranian medicinal plant extracts against helicobacter pylori pomegranate juice decreases amyloid load and improves behavior in a mouse model of alzheimer's disease cardioprotective effect of whole fruit extract of pomegranate on doxorubicin-induced toxicity in rat hydroalcoholic extract based-ointment from punica granatum l. peels with enhanced in vivo healing potential on dermal wounds safety and antioxidant activity of a pomegranate ellagitanninenriched polyphenol dietary supplement in overweight individuals with increased waist size identi fi cation of estrone in pomegranate seeds evolution of juice anthocyanins during ripening of new selected pomegranate ( punica granatum ) clones pomegranate polyphenols down-regulate expression of androgensynthesizing genes in human prostate cancer cells overexpressing the androgen receptor activation of ppar gamma and alpha by punicic acid ameliorates glucose tolerance and suppresses obesity-related in fl ammation chemopreventive effects of pomegranate seed oil on skin tumor development in cd1 mice anti-diabetic action of punica granatum fl ower extract: activation of ppargamma and identi fi cation of an active component pomegranate fl ower improves cardiac lipid metabolism in a diabetic rat model: role of lowering circulating lipids pomegranate fl ower extract diminishes cardiac fi brosis in zucker diabetic fatty rats: modulation of cardiac endothelin-1 and nuclear factor-kappab pathways tannins from the leaves of punica granatum pomegranate juice protects nitric oxide against oxidative destruction and enhances the biological actions of nitric oxide effects of pomegranate juice on hyperoxaluria-induced oxidative stress in the rat kidneys possible interaction between pomegranate juice and warfarin anticancer activities of pomegranate extracts and genistein in human breast cancer cells evaluation of antioxidant, antitumor and immunomodulatory properties of polysaccharide isolated from fruit rind of punica granatum suppressive effect of punica granatum on the production of tumor necrosis factor (tnf) in bv2 microglial cells therapeutic applications of pomegranate ( punica granatum l.): a review antioxidant effect of pomegranate extract in reducing acute in fl ammation due to myringotomy pomegranate juice supplementation to atherosclerotic mice reduces macrophage lipid peroxidation, cellular cholesterol accumulation and development of atherosclerosis crc handbook of ayurvedic medicinal plants effects of oral administration of ellagic acidrich pomegranate extract on ultraviolet-induced pigmentation in the human skin effects of pomegranate chemical constituents/intestinal microbial metabolites on cyp1b1 in 22rv1 prostate cancer cells punica granatum : heuristic treatment for diabetes mellitus punica granatum (pomegranate) fl ower extract possesses potent antioxidant activity and abrogates fe-nta induced hepatotoxicity in mice differentiation-promoting activity of pomegranate ( punica granatum ) fruit extracts in hl-60 human promyelocytic leukemia cells oral consumption of pomegranate fruit extract inhibits growth and progression of primary lung tumors in mice pomegranate fruit extract inhibits prosurvival pathways in human a549 lung carcinoma cells and tumor growth in athymic nude mice pomegranate fruit extract impairs invasion and motility in human breast cancer pomegranate fruit extract inhibits uvb-induced in fl ammation and proliferation by modulating nf-k b and mapk signaling pathways in mouse skin stimulation of osteoblastic differentiation and inhibition of interleukin-6 and nitric oxide in mc3t3-e1 cells by pomegranate ethanol extract chemopreventive and adjuvant therapeutic potential of pomegranate ( punica granatum ) for human breast cancer inhibitory effect of pomegranate on intestinal sodium dependent glucose uptake embryo protective effect of pomegranate ( punica granatum l.) fruit extract in adriamycin-induced oxidative stress screening of traditional chinese medicinal plants for quorum-sensing inhibitors activity pomegranate seed oil rich in conjugated linolenic acid suppresses chemically induced colon carcinogenesis in rats genetic diversity-independent neutralization of pandemic viruses (e.g. hiv), potentially pandemic (e.g. h5n1 strain of in fl uenza) and carcinogenic (e.g. hbv and hcv) viruses and possible agents of bioterrorism (variola) by enveloped virus neutralizing compounds (evncs) pomegranate extract induces apoptosis in human prostate cancer cells by modulation of the igf-igfbp axis effect of pomegranate peel extracts on experimental prostatitis rats in vitro studies on the binding, antioxidant, and cytotoxic actions of punicalagin central nervous system activity of acute administration of ethanol extract of punica granatum l. seeds in mice beta-secretase (bace1) inhibitors from pomegranate ( punica granatum ) husk effects of pomegranate tannins on experimental gastric damages transport behavior of ellagic acid of pomegranate leaf tannins and its correlation with total cholesterol alteration in hepg2 cells punica granatum (pomegranate) and its potential for prevention and treatment of in fl ammation and cancer pomegranate ( punica granatum ) pure chemicals show possible synergistic inhibition of human pc-3 prostate cancer cell invasion across matrigel possible synergistic prostate cancer suppression by anatomically discrete pomegranate fractions immune-suppressive activity of punicalagin via inhibition of nfat activation pharmacokinetic study of ellagic acid in rat after oral administration of pomegranate leaf extract evidence of anti-obesity effects of the pomegranate leaf extract in high-fat diet induced obese mice effect of punica granatum (pomegranate) on sperm production in male rats treated with lead acetate antiviral activities of medicinal herbs traditionally used in southern mainland china punica granatum fl ower extract, a potent alpha-glucosidase inhibitor, improves postprandial hyperglycemia in zucker diabetic fatty rats evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract pomegranate fl ower: a unique traditional antidiabetic medicine with dual ppar-alpha/-gamma activator properties fabrication of nanoparticles using partially puri fi ed pomegranate ellagitannins and gelatin and their apoptotic effects maternal dietary supplementation with pomegranate juice is neuroprotective in an animal model of neonatal hypoxic-ischemic brain injury anti-listeria monocytogenes activity of heat-treated lyophilized pomegranate juice in media and in ground top round beef pomegranate ( punica granatum ) supplements: authenticity, antioxidant and polyphenol composition prostate cancer prevention through pomegranate fruit pomegranate fruit juice for chemoprevention and chemotherapy of prostate cancer effects of pomegranate juice and extract polyphenols on platelet function antimicrobial activities of pomegranate rind extracts: enhancement by addition of metal salts and vitamin c pomegranate seed oil consumption during a period of high-fat feeding reduces weight gain and reduces type 2 diabetes risk in cd-1 mice toxicological evaluation of pomegranate seed oil breast cancer chemopreventive properties of pomegranate ( punica granatum ) fruit extracts in a mouse mammary organ culture volatile composition of pomegranates from 9 spanish cultivars using headspace solid phase microextraction punica granatum (pomegranate) extract is active against dental plaque absorption, metabolism, and antioxidant effects of pomegranate ( punica granatum l.) polyphenols after ingestion of a standardized extract in healthy human volunteers effect of 2 weeks' consumption of pomegranate juice on the pharmacokinetics of a single dose of midazolam: an open-label, randomized, single-center, 2-period crossover study in healthy japanese volunteers cardioprotective potential of punica granatum extract in isoproterenol-induced myocardial infarction in wistar rats effect of pomegranate juice on angiotensin ii-induced hypertension in diabetic wistar rats pomegranate extract improves a depressive state and bone properties in menopausal syndrome model ovariectomized mice fruits of warm climates. julia f identi fi cation and quanti fi cation of phenolic compounds and their effects on antioxidant activity in pomegranate juices of eight iranian cultivars indian materia medica with ayurvedic pomegranate extract induces cell cycle arrest and alters cellular phenotype of human pancreatic cancer cells medicinal plants in the republic of korea nmr spectral analysis of polyphenols from punica granatum antibacterial activity directed isolation of compounds from punica granatum antioxidant and antimutagenic activities of pomegranate peel extracts potential of pomegranate husk carbon for cr(vi) removal from wastewater: kinetic and isotherm studies the existence of pelletierine derivatives in punica granatum alkaloids in the bark of punica granatum l. (pomegranate) from yugoslavia punica granatum (pomegranate) juice provides an hiv-1 entry inhibitor and candidate topical microbicide antioxidant activities of pomegranate fruit extract and its anthocyanidins: delphinidin, cyanidin, and pelargonidin evaluation of antioxidant activity, colour and some nutritional characteristics of pomegranate ( punica granatum l.) juice and its sour concentrate processed by conventional evaporation agroforestree database: a tree reference and selection guide version 4 protective effects of standardized pomegranate ( punica granatum l.) polyphenolic extract in ultraviolet-irradiated human skin fi broblasts antifungal ef fi cacy of punica granatum , acacia nilotica , cuminum cyminum and foeniculum vulgare on candida albicans : an in vitro study antioxidant capacity and lipid characterization of six georgia-grown pomegranate cultivars phase ii study of pomegranate juice for men with rising prostate-speci fi c antigen following surgery or radiation for prostate cancer antimicrobial ellagitannin from pomegranate ( punica granatum ) fruits extract of punica granatum inhibits skin photoaging induced by uvb irradiation medicinal values of fruit peels from citrus sinensis , punica granatum , and musa paradisiaca with respect to alterations in tissue lipid peroxidation and serum concentration of glucose, insulin, and thyroid hormones safety assessment of pomegranate fruit extract: acute and subchronic toxicity studies the wound healing activity of fl ower extracts of punica granatum and achillea kellalensis in wistar rats antioxidant properties of gallocatechin and prodelphinidins from pomegranate peel searchable world wide web multilingual multiscript plant name database antibacterial activity of punica granatum l. against gastro intestinal tract infection causing organisms the effects of pomegranate seed extract and {beta}-sitosterol on rat uterine contractions antioxidant potentials of punica granatum fruit rind extracts pomegranate extract inhibits the interleukin-1 b -induced activation of mkk-3, p38 a -mapk and transcription factor runx-2 in human osteoarthritis chondrocytes antioxidant, antimalarial and antimicrobial activities of tannin-rich fractions, ellagitannins and phenolic acids from punica granatum l studies on the chemical constituents from xinjiang punica granatum pomegranate extract inhibits androgen-independent prostate cancer growth through a nuclear factor-kappab-dependent mechanism antioxidant activity of punica granatum fruits the occurrence of 2-(2-propenyl)-d 1-piperideine in the leaves of pomegranate consumption of wonderful variety pomegranate juice and extract by diabetic patients increases paraoxonase 1 association with high-density lipoprotein and stimulates its catalytic activities pomegranate juice protects macrophages from triglyceride accumulation: inhibitory effect on dgat1 activity and on triglyceride biosynthesis anti-oxidative effects of pomegranate juice (pj) consumption by diabetic patients on serum and on macrophages pomegranate byproduct administration to apolipoprotein e-de fi cient mice attenuates atherosclerosis development as a result of decreased macrophage oxidative stress and reduced cellular uptake of oxidized lowdensity lipoprotein free radical scavenging, antiglycation and tyrosinase inhibition properties of a polysaccharide fraction isolated from the rind from punica granatum pomegranate juice sugar fraction reduces macrophage oxidative state, whereas white grape juice sugar fraction increases it antiplaque and antigingivitis effects of a gel containing punica granatum linn extract: a double-blind clinical study in humans assessment of the genotoxic risk of punica granatum l. (punicaceae) whole fruit extracts ellagitannin-rich pomegranate extract inhibits angiogenesis in prostate cancer in vitro and in vivo pomegranate juice inhibits sulfoconjugation in caco-2 human colon carcinoma cells carbonic anhydrase inhibitors from the pericarps of punica granatum l investigation of a betainic alkaloid from punica granatum antioxidant and eicosanoid enzyme inhibition properties of pomegranate seed oil and fermented juice fl avonoids bioavailability of ellagic acid in human plasma after consumption of ellagitannins from pomegranate ( punica granatum l.) juice in vitro antiproliferative, apoptotic and antioxidant activities of punicalagin, ellagic acid and a total pomegranate tannin extract are enhanced in combination with other polyphenols as found in pomegranate juice rapid large scale puri fi cation of ellagitannins from pomegranate husk, a by-product of the commercial juice industry pomegranate juice ellagitannin metabolites are present in human plasma and some persist in urine for up to 48 hours pomegranate ellagitannin-derived metabolites inhibit prostate cancer growth and localize to the mouse prostate gland pomegranate juice and extracts provide similar levels of plasma and urinary ellagitannin metabolites in human subjects growth inhibition of entamoeba histolytica and e . invadens produced by pomegranate root ( punica granatum l.) lc-dad-esi/ms(n) determination of direct condensation fl avanol-anthocyanin adducts in pressure extracted pomegranate ( punica granatum l.) juice pomegranate wine has greater protection capacity than red wine on low-density lipoprotein oxidation nutritive and antioxidative potential of fresh and stored pomegranate industrial byproduct as a novel beef cattle feed central council for research in ayurveda & siddha (2002) database on medicinal plants used in ayurveda antibacterial activity of medicinal plants against pathogens causing complicated urinary tract infections effects of fruit ellagitannin extracts, ellagic acid, and their colonic metabolite, urolithin a, on wnt signaling macrophage paraoxonase 2 (pon2) expression is up-regulated by pomegranate juice phenolic anti-oxidants via ppar gamma and ap-1 pathway activation bioavailable constituents/metabolites of pomegranate ( punica granatum l.) preferentially inhibit cox2 activity ex vivo and il-1beta-induced pge2 production in human chondrocytes in vitro consumption of hydrolyzable tannins-rich pomegranate extract suppresses in fl ammation and joint damage in rheumatoid arthritis use of combined traditional chinese and western medicine in the management of burns traditional medicine in fiji: some herbal folk cures used by fiji indians medicinal plants from ujjain district madhya pradesh. part ii exploring the ameliorative potential of punica granatum in dextran sulfate sodium induced ulcerative colitis in mice pharmacological investigations of punica granatum in glycerol-induced acute renal failure in rats philippine alternative medicine. manual of some philippine medicinal plants in vitro effects of pomegranate juice and pomegranate polyphenols on foodborne viral surrogates flavonoids from punica granatum : potential antiperoxidative agents punica granaum l effects of pomegranate juice consumption on myocardial perfusion in patients with coronary heart disease in fl uenza virus variation in susceptibility to inactivation by pomegranate polyphenols is determined by envelope glycoproteins designing of novel carbonic anhydrase inhibitors and activators photochemopreventive effect of pomegranate fruit extract on uva-mediated activation of cellular pathways in normal human epidermal keratinocytes punicafolin, an ellagitannin from the leaves of punica granatum xl: revision of the structures of punicalin and punicalagin, and isolation and characterization of 2-o -galloylpunicalin from the bark of punica granatum l tannins and related compounds. xli: isolation and characterization of novel ellagitannins, punicacorteins a, b, c, and d, and punigluconin from the bark of punica granatum l tannins and related compounds. c. reaction of dehydrohexahydroxydiphenic acid esters with bases, and its application to the structure determination of pomegranate tannins, granatins a and b humarain: a new dimeric gallic acid glycoside from punica granatum l. bark nutritive value of pomegranate fruit and juice preliminary studies on the anti-angiogenic potential of pomegranate fractions in vitro and in vivo pomegranate peel extract prevents liver fi brosis in biliary-obstructed rats punica granatum peel extract protects against ionizing radiationinduced enteritis and leukocyte apoptosis in rats pomegranate ( punica granatum ) seed linolenic acid isomers: concentrationdependent modulation of estrogen receptor activity molluscicidal activity of punica granatum bark and canna indica root enzyme inhibition by the molluscicidal agent punica granatum linn. bark and canna indica linn. root the effect of pomegranate juice supplementation on strength and soreness after eccentric exercise protective effect of a potent antioxidant, pomegranate juice, in the kidney of rats with nephrolithiasis induced by ethylene glycol effects of pomegranate juice consumption on sperm quality, spermatogenic cell density, antioxidant activity and testosterone level in male rats antioxidant activity, polyphenol content, and related compounds in different fruit juices and homogenates prepared from 29 different pomegranate accessions usda) (2012) usda national nutrient database for standard reference, release 25. nutrient data laboratory home page in vitro antimalarial activity and cytotoxicity of some selected cuban medicinal plants rapid dereplication of estrogenic compounds in pomegranate ( punica granatum ) using on-line biochemical detection coupled to mass spectrometry use of punica granatum as an antifungal agent against candidosis associated with denture stomatitis minimum inhibitory concentration of adherence of punica granatum linn (pomegranate) gel against s. mutans , s. mitis and c. albicans studies on the toxicity of punica granatum l. (punicaceae) whole fruit extracts activity of medicinal plant extracts against hospital isolates of methicillin-resistant staphylococcus aureus medicinal plant extracts as anti-escherichia coli o157:h7 agents and their effects on bacterial cell aggregation pomegranate seed oil, a rich source of punicic acid, prevents diet-induced obesity and insulin resistance in mice punica granatum attenuates angiotensin-ii induced hypertension in wistar rats bioactive compounds from the seeds of punica granatum (pomegranate) constituents of the fl owers of punica granatum pomegranate: constituents, bioactivities and pharmacokinetics cellular and molecular mechanisms of pomegranate juice-induced anti-metastatic effect on prostate cancer cells pomegranate extract, a prooxidant with antiproliferative and proapoptotic activities preferentially towards carcinoma cells pomegranate polyphenols and resveratrol protect the neonatal brain against hypoxic-ischemic injury investigation of the alkaloids of punica granatum investigation of the alkaloids of punica granatum l. by partition chromatography antimutagenicity of some fl owers grown in thailand pomegranates ( punica granatum ), kiwifruit ( actinidia deliciosa ) and blood pressure: a pilot study medicinal fl owers. xxiii. new taraxastane-type triterpene, punicanolic acid, with tumor necrosis factor-alpha inhibitory activity from the fl owers of punica granatum effect of pomegranate peel extracts on oxidative stress in restrained mice pomegranate fl ower ameliorates fatty liver in an animal model of type 2 diabetes and obesity dietary effect of pomegranate seed oil on immune function and lipid metabolism in mice chitinase iii in pomegranate seeds ( punica granatum linn.): a high-capacity calcium-binding protein in amyloplasts inhibitory effect of an ellagic acid-rich pomegranate extract on tyrosinase activity and ultravioletinduced pigmentation a triglyceride from punica granatum broad spectrum antimutagenic activity of antioxidant active fraction of punica granatum l. peel extracts screening of certain medicinal plants from india for their anti-quorum sensing activity inhibition of uvb-mediated oxidative stress and markers of photoaging in immortalized hacat keratinocytes by pomegranate polyphenol extract pomx studies on physicochemical properties and bioactive compounds of six pomegranate cultivars antiviral activity of tannin from the pericarp of punica granatum l. against genital herpes virus in vitro antiliperoxidant activity of pomegranate peel extracts on lard dietary antioxidants improve arteriogenic erectile dysfunction key: cord-354044-3ugc7odq authors: salazar-gómez, anuar; ontiveros-rodríguez, julio c.; pablo-pérez, saudy s.; vargas-díaz, m. elena; garduño-siciliano, leticia title: the potential role of sesquiterpene lactones isolated from medicinal plants in the treatment of the metabolic syndrome – a review date: 2020-09-16 journal: s doi: 10.1016/j.sajb.2020.08.020 sha: doc_id: 354044 cord_uid: 3ugc7odq metabolic syndrome comprises a cluster of metabolic disorders related to the development of cardiovascular disease and type 2 diabetes mellitus. in latter years, plant secondary metabolites have become of special interest because of their potential role in preventing and managing metabolic syndrome. sesquiterpene lactones constitute a large and diverse group of biologically active compounds widely distributed in several medicinal plants used for the treatment of metabolic disorders. the structural diversity and the broad spectrum of biological activities of these compounds drew significant interests in the pharmacological applications. this review describes selected sesquiterpene lactones that have been experimentally validated for their biological activities related to risk factors of metabolic syndrome, together with their mechanisms of action. the potential beneficial effects of sesquiterpene lactones discussed in this review demonstrate that these substances represent remarkable compounds with a diversity of molecular structure and high biological activity, providing new insights into the possible role in metabolic syndrome management. metabolic syndrome (mets) refers to a cluster of risk factors related to the development of cardiovascular disease (cvd) and type 2 diabetes mellitus (t2dm) (alberti et al., 2009 ). this pathological condition represents a public health concern in most nations due to its association with mortality caused by the cardiovascular and metabolic complications (ju et al., 2017) . indeed, mets is recognized as a risk factor that influences progression and prognosis of coronavirus disease 2019, the infectious disease caused by the most recently discovered coronavirus sars-cov-2 (costa et al., 2020) . lifestyle modifications remain the primary component of metss risk factors reduction and pharmacological therapies are indicated in special situations to improving more than one factor (larsen et al., 2018) . in latter years, secondary plant metabolites have become of special interest in the scientific community because of their potential role in preventing and managing mets (cicero and colletti, 2016; francini-pesenti et al., 2019) . many compounds, such as sesquiterpene lactones (slns), have been isolated from medicinal plants and their hypoglycemic, anti-inflammatory, and antioxidative properties coupled with their capacity to modulate key cellular functions have been confirmed by in vitro and in vivo methods (chadwick et al., 2013; chaturvedi et al., 2016; alonso et al., 2018) . despite these effects are linked to the pathogenesis of mets, the role of these compounds to avoid its progression is not well documented compared to many other compounds such as polyphenols into which a great deal of research has been conducted. therefore, in order to provide relevant information regarding the potential benefits of slns in preventing abbreviations: ace, angiotensin i-converting enzyme; ampk, activated protein kinase; apoc3, apolipoprotein c3; at, adipose tissue; cat, catalase; cox-2, cyclooxygenase 2; cvd, cardiovascular disease; ffa, free fatty acids; fn, fibronectin; g6pase, glucose-6-phosphatase; gk, glucokinase; gpx, glutathione peroxidase; gsh, reduced glutathione; hdl-c, high-density lipoproteins-cholesterol; ifn-g, interferon gamma; il-1b, interleukin 1 beta; il-6, interleukin 6; inos, inducible nitric oxide synthase; ir, insulin resistance; jnk, c-jun n-terminal kinases; ldl-c, low-density lipoprotein-cholesterol; lps, lipopolysaccharide; mapk, mitogen-activated protein kinases; mcp-1, monocyte chemoattractant protein 1; mets, metabolic syndrome; nf-kb, nuclear factor kappa b; no, nitric oxide; ros, reactive oxygen species; slns, sesquiterpene lactones; sod, superoxide dismutase; stat1, signal transducer and activator of transcription 1; stz, streptozotocin; t2dm, type 2 diabetes mellitus; tbars, thiobarbituric acid reactive substances; tc, total cholesterol; tg, triglycerides; tgf-b1, transforming growth factor beta; tlrs, toll-like receptor; tnf-a, tumor necrosis factor alpha; vldl, very-low-density lipoprotein and managing mets, this review addresses plant-derived slns that are potentially responsible for the positive effect in improving risk factors associated with mets. an electronic literature search was conducted on slns with hypoglycemic and/or hypolipidemic effects and isolated from plants used in traditional medicine for the same purposes. the search was done in databases of google scholar, science direct, and scifinder until june 2020 using the keyword sesquiterpene lactones and following terms: metabolic syndrome, hypoglycemic, hypolipidemic, antidiabetic, antihypertensive, and medicinal plants. additional information was identified from references located in the retrieved articles. although many slns were screened in some of the studies, only those considered active by the authors are included in this review. the plants included in this review were selected based on their ethnomedicinal records. for each species, the currently accepted name in the online "the plant list" database has been checked and the reported name has been replaced with the current one. compound class, plant source, biological activity and important aspects related with mets are summarized in the table 1 . mets is defined as a cluster of risk factors such as raised blood pressure, atherogenic dyslipidemia, raised fasting glucose, and central obesity, related to the development of cvd and t2dm (alberti et al., 2009) . since the world health organization (who) reported the first formalized definition of the mets, the diagnostic criteria have been sequentially developed by several public health organizations (engin, 2017) . nowadays, the most recognized criterion for the clinical diagnosis of mets (alberti et al., 2009 ) is based on identifying at least three of the following risk factors: (1) elevated waist circumference (population and country-specific definitions determined by local organizations); (2) triglycerides (tg) 150 mg/ dl (<1.0 mmol/l) or on drug treatment for elevated triglycerides; (3) high-density lipoproteins-cholesterol (hdl-c) <40 mg/dl (<1.0 mmol/l) in men or <50 mg/dl (<1.3 mmol/l) in women or on drug treatment for reduced hdl-c; (4) blood pressure 130/ 85 mmhg or on antihypertensive medication treatment, and/or a history of hypertension; and (5) fasting glucose >100 mg/dl (>5.6 mmol/l) or on drug treatment for elevated glucose. the mechanisms underlying pathogenesis of mets have not been completely explored, but obesity-induced adipocyte dysfunction and inflammation is associated with the progression of insulin resistance and metabolic disorders (kl€ oting and bl€ uher, 2014) . body fat mass accumulation in obesity depends on different factors including the relationship of energy intake to energy expenditure and body energy storage (gomez-hernandez et al., 2016) . adipose tissue (at) plays an important role as an energy storage organ, as well as an endocrine organ produces adipokines such as leptin, adiponectin, monocyte chemoattractant protein 1 (mcp1), tumor necrosis factor alpha (tnfa) and interleukin 6 (il-6), which circulate and regulate systemic metabolism and inflammation. the cell type composition of at includes adipocytes, fibroblasts, macrophages, stromal cells, monocytes and preadipocytes (r afols, 2014) . on further at expansion, hypertrophy of adipocytes and increased secretion of macrophage chemoattractants occurs, including the secretion of mcp-1, which recruits additional macrophages. these actions in turn result in local inflammatory state, enhanced basal lipolysis, increasing the leakage of free fatty acids (ffa) and a dysregulated secretion of several proinflammatory adipokines (longo et al., 2019; xu et al., 2019) . subsequently, these adverse signals reach metabolic tissues (e.g. liver, pancreatic islets, and skeletal muscle) and modify inflammatory responses as well as glucose and lipid metabolism, thereby contributing to a global metabolic effect of insulin resistance. chronic low-grade inflammation in obesity results from the activation of various inflammatory mechanisms through nuclear factor kappa b (nf-kb) and c-jun n-terminal kinases (jnk) pathways. these pathways represent important modulators of cytokine gene expression downstream of toll-like receptors (tlrs) in insulin target cells (catrysse and van loo, 2017; rogero and calder, 2018) . nf-kb is an important transcription factor involved in different processes of the immune and inflammatory responses. it is composed of p50 and p65 subunits and is found in the cytoplasm in complex with inhibitory proteins of the ikb family. cytokines and lipopolysaccharide (lps) can stimulate cell surface receptors including toll-like receptor (tlr4) to initiate a signaling cascade that converge on the activation of the inhibitor of kb kinase (ikk) complex (baker et al., 2011) . the ikk complex phosphorylates ikba and induces its degradation, leading to the release and nuclear translocation of nf-kb to promote transcription of target genes such as tnf-a, interleukin-1beta (il-1b), il-6, il-8, cyclooxygenase 2 (cox-2) and inducible nitric oxide synthase (inos) (knab et al., 2014; ruan et al., 2011) . on the other hand, jnk are members of the mitogen-activated protein kinases (mapk) that mediate cellular responses to a variety of intra-and extracellular stresses (zeke et al., 2016) . in the context of obesity, jnk pathways can be activated by proinflammatory cytokines, ffa and reactive oxygen species (ros), and regulate several nuclear and extra-nuclear substrates, specially the transcription factor activator protein 1 (ap1) which controls the expression of proinflammatory genes and protein synthesis (e.g. tnf-a, il-1b, il-6 and il-8) (pal et al., 2016; feng et al., 2020) . deregulated activation of nf-kb and jnk pathways results in increased transcription of il-6 and tnf-a, which reduce the sensitivity of insulin target cells towards insulin. thus, chronically activated nf-kb and jnk pathways leads to the promotion of insulin resistance (yung and giacca, 2020) . additionally, increased flux of ffa to the liver in the insulin resistant state stimulates production tg and secretion in the form of verylow-density lipoprotein (vldl). the resulting hypertriglyceridemia leads to lower hdlàc levels and normal or slightly elevated lowdensity lipoprotein-cholesterol (ldl-c) levels (iqbal et al., 2018) . this is related to the typical dyslipidemic profile in mets. consistent with a potential role in the pathogenesis of mets, slns interfering with these processes described above could be useful to prevent the onset of insulin resistance and the risk of t2dm and cvd in obese individuals. slns represent a diverse group of terpenoids with more than 5000 different elucidated structures. they are particularly diversified in the compositae (asteraceae) family, but also occurring in apiaceae, illiciaceae, magnoliaceae, solanaceae, and euphorbiaceae families (padilla-gonzalez et al., 2016) . numerous species of these families are used in traditional medicine and slns have been described as their primary active constituents. these compounds possess several biological activities such as anti-inflammatory, antidiabetic, antimalarial, anti-proliferative, anti-parasitic and antimicrobial (merfort, 2011; chadwick et al., 2013; chaturvedi et al., 2011). slns are characterized by the presence of a g-lactone ring. the lactone ring can be fused to the remaining skeleton in either a cis or trans configuration, being most common the trans configuration (fischer et al., 1979; fischer, 1990; . based on their carbocyclic skeleton, slns are mainly classified in four major groups: germacranolides (10-membered ring), eudesmanolides (6à6 bicyclic compounds), guaianolides and pseudoguaianolides (5à7 blood glucose levels (#), hba1c (#), plasma insulin ("), tissue glycogen (") tc, tg and ldl-c (#); hdl-c (") tbars levels (#), gsh ("), sod, cat and gpx (") in brain, liver, heart, kidney, and pancreas eliza et al., 2009a eliza et al., , 2009b eliza et al., , 2010 5 costunolide germacrolide costus speciosus 6 alantolactone eudesmanolide inula helenium antiinflammatory-associated to glucose intolerance and ir (in vitro) antiinflamatory-obesity-induced ir (in vitro) attenuates lipid accumulation (in vitro) antiinflamatory-associated to diabetic nephropathy (in vivo) stat3 inhibitor. inhibition of the tlr4 gene expression. inhibition of tlr4-jnk signaling. il-6 and mcp-1 (#). apoc3 expression at both mrna and protein levels (#) tnf-a and il-6 (#) in diabetic kidney. serum creatinine and urea nitrogen levels (#). kim et al., 2017a kim et al., , 2017b yang et al., 2018; zhu et al., 2020 7 tirotundin 3,10epoxygermacranolide antidiabetic (in vitro) dual ppara/g agonists lin, 2012 8 tagitinin a 9 tagitinin g anti-hyperglycemic (in vitro) glucose uptake in 3t3-l1 adipocytes ("). blood glucose levels (#), serum insulin and pancreatic insulin levels (") g6pase activity (#) and gk activity (") tc, tg, ldl-c and vldl (#); hdl-c (") tbars levels (#), sod, cat and gpx (") in liver, kidneys, and pancreas tnf-a levels (#). normalization of blood pressure hong et al., 1999 hong et al., , 2005 reduction (#); increment ("); thiobarbituric acid reactive substances (tbars); reduced glutathione (gsh); superoxide dismutase (sod); catalase (cat); glutathione peroxidase (gpx); insulin resistance (ir); toll-like receptor 4 (tlr4); c-jun n-terminal kinases (jnk); interleukin 6 (il-6); monocyte chemoattractant protein 1 (mcp-1); apolipoprotein c3 (apoc3); amp-activated protein kinase (ampk); peroxisome proliferator-activated receptors a and g (ppara/g); nuclear factor kappa b (nf-kb); transforming growth factor beta (tgf-b1); fibronectin (fn); glucose-6-phosphatase (g6pase); glucokinase (gk); cyclooxygenase 2 (cox-2); interferon-gamma (ifn-g); tumor necrosis factor a (tnf-a); angiotensin i-converting enzyme (ace). a. salazar-g omez et al. / south african journal of botany 135 (2020) 1à12 bicyclic compounds) and many subtypes of slns according to their skeletal arrangement (adekenov, 2017; padilla-gonzalez et al., 2016) . in many cases, the g-lactone ring contains an exocyclic double bond conjugated to the carbonyl group (a-methylene-g-lactone) but in some cases the exocyclic methylene is reduced or the double bond can be endocyclic (martínez et al., 2012; padilla-gonzalez et al., 2016; . it has been well documented that biological activity of the most common types of slns is mainly attributed to formation of covalent union between the a,b-unsaturated group in the exo-methylene-g-lactone and nucleophilic biological targets (e.g. free cysteine sulfhydryl) resulting in alkylation through michael-type addition (schmidt, 2006) . this chemical reaction induces steric and chemical changes in enzymes, receptors or transcriptional factors leading to a series of cellular events that culminate in diverse biologic responses. the number of alkylating structural elements present on the molecule define differences between the activity of each sln. another structural influences on the biological effects are the molecular size, hydrophobicity, chemical environment and the presence of other functional groups (e.g., epoxy groups, hydroxyls or hydroxyls esterified with acetate, propionate, isobutyrate, angelate, epoxyangelate, and benzoate) (chaturvedi, 2011; ivanescu et al., 2015; padilla-gonzalez et al., 2016; . the structural diversity and the broad spectrum of biological activities drew significant interests in the pharmacological applications of slns (moujir et al., 2020) . many slns have proved to have a significant anti-inflammatory, hypoglycemic and hypolipidemic activity therefore making them attractive for mets therapy (chaturvedi, 2011; chaturvedi et al., 2016) . 6.1. enhydrin from smallanthus sonchifolius (poepp.) h.rob smallanthus sonchifolius (poepp.) h.rob., commonly known as yacon, is a perennial herbaceous plant native to the andean regions of south america (caetano et al., 2016) . yacon is consumed as a safety dietary supplement and because of its low glucose content and high fructooligosaccharide levels putative antidiabetic effects were suggested (delgado et al., 2013) . indeed, this suggestion is supported by the hypoglycemic (aybar et al., 2001; baroni et al., 2008) and hypolipidemic (miura et al., 2004; habib et al., 2011) reported activities. also, a potential use in metabolic disorders could be proposed based on the anti-inflammatory and antioxidant properties (feltenstein et al., 2004; sousa et al., 2015) . besides the above mentioned evidences, enhydrin (1), a melampolide (cis,trans-germacranolide) and the major sesquiterpene lactone component in leaves of s. sonchifolius, has proven to be effective reducing post-prandial glucose levels and a useful compound for blood glucose control by the induction of a late increase in plasma insulin in streptozotocin (stz)induced diabetic rats (genta et al., 2010) . more recently, in vivo and in vitro experiments showed that enhydrin (1) is effective in the management of post-prandial hyperglycemia through inhibition of a-glucosidase in the small intestine (serra-barcellona et al., 2017) . the inhibition of this enzyme has been linked to the presence of the a,b-unsaturatedg-lactone ring system (yin et al., 2014) , similar to the intact exo-methylene-g-lactone group in 1 (fig. 1) . thus, the antia-glucosidase activity of enhydrin could be derived from this interaction. in addition, the alkylation of nucleophilic sites of factors involved in early stages of the inflammatory cascade described above allows to relate the anti-inflammatory properties reported for 1 with the presence of the exo-methylene-g-lactone ring system (feltenstein et al., 2004; ma et al., 2007) . regarding toxicological studies, it has been reported that a single oral administration of enhydrin (1) at doses of 1.6, 4 and 8 mg/kg body weight (b.w.) did not caused deaths or acute toxic effects within 7 days in male and female rats (genta et al., 2010) . in acute study in rats, there were no deaths or signs of toxicity observed after single oral administration of 1 at any dose level up to the highest dose tested (0.32 g/kg b.w.) within 14 days. in subchronic studies, after oral administration for 90 days at daily doses of 0.4, 0.8 and 8.0 mg/ kg b.w., did not caused hematological, biochemical and histological alterations in rats (serra et al., 2012) . smallanthus macroscyphus (heliantheae, asteraceae), is a perennial herb commonly known as ''wild yacon'' native from the south american region comprising from southern bolivia to northwestern argentina. this species is closely related to s. sonchifolius and possibly with similar antidiabetic properties. polymatin a (2) is the main sesquiterpene lactone isolated from s. macroscyphus (de pedro et al., 2003) . this melampolide exerts an effective inhibition of post-prandial blood glucose peak and hypoglycemic activity in stz-diabetic rats probably by the stimulation of insulin release or due to an insulin-like effect (serra-barcellona et al., 2014) . due to the close relationship in the polymatin a (2) and enhydrin (1) structures, the melampolide 2 could be effective in the management of postprandial hyperglycemia through inhibition of a-glucosidase. however, no studies of these effects were found. in contrast to the c4àc5 epoxy group in enhydrin (1), polymatin a (2) presents a double bond (fig. 1 ). c4àc5 epoxy groups in melampolides such as enhydrin have been reported to hinder the ability of these compounds to inhibit nf-kb dna binding responsible to cytokines expression (schorr et al., 2007) commonly observed in inflammatory response. conversely, the effect is favored by the presence of a double bond between c-4àc-5 in other melampolides (schorr et al., 2007) . hence, hopeful results could be expected in future studies to explore anti-inflammatory activity in polymatin a. acute oral toxicity of polymatin a (2) in normal healthy rats at doses assayed (0.7, 1.4 and 2.8 g dried powder/kg b.w.) do not produced deaths or acute toxic effect (changes in behavior or posture, presence of convulsions or occurrence of secretions) within 14 days. the doses were well tolerated and did not produce adverse nutritional effect. no gastrointestinal symptom such as diarrhea or constipation were observed at the doses assayed. volume, ph and urine specific gravity were within normal ranges. no nitrites, protein or blood were detected in the urine samples of the animal groups treated (serra-barcellona et al., 2014) . in subchronic studies, polymatin a (2) was orally administered to wistar rats for 90 days at daily doses of 7, 14 and 28 mg/kg b.w. no toxicity signs or deaths were observed. there were no changes in the behavior, body or organ weights, hematological, biochemical or urine parameters of the rats. no histopathological lesions were observed in the examined organs. the results indicate that polymatin a (2) from s. macroscyphus leaves may be considered as nontoxic substance at a wide range of doses (serra-barcellona., 2016) . the common sunflower, helianthus annuus linn (asteraceae), is a well-known plant with edible seeds, flower petals and tender leaf petioles. this plant was proposed to offer a variety of medical benefits (lim, 2014; guo et al., 2017) . to provide a scientific explanation for its use in nigerian traditional medicine, onoja and anaga (2014) reported a hypoglycemic effect on the fasting blood glucose level in alloxan-induced diabetic rats after a single dose of the methanolic extract of h. annuus leaves. this study led to the recent isolation of the heliangolide 20-dehydroeucannabinolide (3) (fig. 1) . (onoja et al., 2020) . heliangolide slns represent an isomeric form of germacranolides with a cyclodecadiene skeleton and double bonds at c1=c10 and c4=c5, which stereochemical configurations are trans, cis respectively (s€ ulsen and martino, 2018). the heliangolide 3 reduced the fasting blood glucose level at dose of 0.2 mmol/kg in alloxaninduced diabetic rats (onoja et al., 2020) . the authors suggested that this sesquiterpene lactone might have reducing effects in glucose absorption based on the heliangolide derivative structure, which presents an intact exo-methylene-g-lactone group. as mentioned above, a,b-unsaturated g-lactone ring system has an important relation in the inhibition of a-glucosidase activity, thus the heliangolide 3 may be inhibiting this enzyme similar to enhydrin (1). in addition to blood glucose regulation, it has also been demonstrated the positive effects of hydromethanolic leaf extract of h. annuus l. on other components of mets, including reduced ldl-c and tg levels as well as hepatoprotective and antilipid peroxidation activities of alloxan-induced diabetic rats (onoja et al., 2018) . since 20-dehydroeucannabinolide (3) is one of the major components of the extract, potential activity of this molecule in managing dyslipidemia may be proposed. however, additional studies are needed to ascertain the hypolipidemic property of this compound. no in vivo toxicity studies on 20-dehydroeucannabinolide (3) have been reported to date. costus speciosus (j. koenig) sm is a plant used in traditional medicine in south asia to treat diabetic patients by eating one leaf of this species per day to regulate blood glucose levels (waisundara et al., 2015) . also, the hypoglycemic effect of c. speciosus root crude extracts have been reported (daisy et al., 2008) . eremanthin (4) (fig. 1) is a guaianolide sesquiterpene lactone present in c. speciosus and other plants such as pterodon pubescens (benth.) benth., eremanthus elaeagnus (mart. ex dc.) sch.bip. and laurus nobilis l. (eliza et al., 2009a; waisundara et al., 2015) . another sesquiterpene lactone reported to be present in c. speciosus is the germacrolide (a trans, trans-germacranolide) costunolide (5) (fig. 1) (eliza et al., 2009b) , which has been also isolated from magnolia spp, laurus nobilis and saussurea costus (falc.) lipsch (koo et al., 2001) . studies in stz-induced diabetic rats showed that oral administration of 4 and 5 decreased plasma glucose level, glycosylated hemoglobin (hba1c), total cholesterol (tc), tg, ldl-c and at the same time markedly increased plasma insulin, tissue glycogen and hdl-c (eliza et al., 2009a (eliza et al., , 2009b . the specific mechanism of eremanthin (4) bioactivity is not completely characterized, but the experimental model used in both works allowed the authors to suggest that this molecule might exert an insulin-like effect on peripheral tissues by either promoting glucose uptake metabolism, by inhibiting hepatic gluconeogenesis or by absorption of glucose into the muscle and adipose tissues through the stimulation of a regeneration process and revitalization of the remaining b cells (eliza et al., 2009a (eliza et al., , 2009b ). in addition, costunolide (5) has shown to suppress lps-induced nf-kb activation that leads to the suppression of inos and a consequent nonproduction of no. this activity was stronger than the observed for parthenolide, a germacranolide sesquiterpene lactone (koo et al., 2001) . thus, the anti-inflammatory activity exhibited by 5 serve as a promising and expanding strategy for treatment of metabolic disease-associated inflammation. on the other hand, the possible inhibition of inflammatory processes has not been studied in eremanthin (4). however, this compound has a rigid skeleton and an intact exo-methylene-g-lactone group, previously related to anti-inflammatory properties (simonsen et al., 2013) . additionally, the absence of free hydroxyl groups in 4 could help to improve anti-inflammatory properties since an increasing number of free hydroxyl groups are reported to diminish nf-kb inhibition activity (simonsen et al., 2013) . taking together these structural characteristics, we suggest that eremathin (4) is a candidate to be tested for inhibition of inflammatory processes related to metabolic diseases. acute oral toxicity of eremanthin (4) and costunolide (5) in normal healthy male wistar rats at doses assayed (10, 20, 40, 80 and 160 mg/kg b.w.) do not produced behavioral changes on the rats and mortality was not observed during acute toxicity test (10 days) (eliza et al., 2010) . finally, the antioxidant activity of eremanthin (4) and costunolide (5) has been demonstrated by significantly decreasing of the thiobarbituric acid reactive substances (tbars) and lipid peroxidation markers levels as well as by increasing reduced glutathione (gsh) levels and enzymatic antioxidants (eliza et al., 2010) . this activity could indicate a protective effect of both on oxidative stress in diabetes. inula (asteraceae) is one of the most popular herbs in traditional chinese medicine. this genus comprises more than one hundred species widely distributed throughout asia, africa, and europe, and many of these have been used to treat a wide range of diseases such as bronchitis, diabetes, obesity, hypertension, and inflammation (seca et al., 2014) . extracts of inula spp. such as inula britannica l., inula viscosa [the accepted name is dittrichia viscosa (l.) greuter.], inula racemosa hook.f., inula helenium l., etc., have been documented for their potential effects on some components of mets, especially hypoglycemic, hypolipidemic and antioxidant activities (kobayashi et al., 2002; zeggwagh et al., 2006; shan et al., 2006; ajani et al., 2009 ) as well as inhibition of a-glucosidase enzyme (orhan et al., 2017) . regarding bioactive secondary metabolites, slns represent the largest group of compounds occurring in inula spp. many of these compounds were isolated from plants mentioned above and demonstrated to exert diverse biological activities (seca et al., 2014; wang et al., 2014) . the anti-inflammatory mechanisms of some slns have been related to their influence on directly inhibit the mapk and block the activation of nf-kb, thus achieving the prevention of pro-inflammatory signaling (han et al., 2001; park et al., 2013) . alantolactone (6) (fig. 1) is the most known eudesmanolide present in several inula species, including inula helenium l. used for hypoglycemic and antiobesity purposes (seca et al., 2014; wang et al., 2014) . this compound has been extensively studied for its antitumor, antioxidant and anti-inflammatory effects (moujir et al., 2020) . regarding anti-inflammatory activity, the eudesmanolide 6 suppresses no, pge 2 and tnf-a production in lps-stimulated raw 264.7 cells by modulating the activity of the nf-kb and mapk signaling pathways (chun et al., 2012) , and it also suppresses tnf-a and interferon gamma (ifn-g)-induced production of chemokines by blocking the signal transducer and activator of transcription 1 (stat1) phosphorylation in hacat cells (lim et al., 2015) . as previously mentioned, it is recognized the fact that tlrs are responsible for the activation of inflammatory pathways in obesity state. in vitro trials confirmed that alantolactone (6) prevents the increase of il-6 levels and regulates macrophage infiltration by reduction of mcp-1 concentrations via inhibition of the tlr4-jnk pathway in both, lean (adipocytes) and obese (adipocyte-macrophage) states (kim et al., 2017a (kim et al., , 2017b . besides the effect on adipocytes, alantolactone (6) can also act in skeletal muscle and liver cells. in this context, the compound 6 inhibits il-6-induced insulin-stimulated glucose intolerance and insulin resistance in the skeletal muscle through blockade the activation of stat3 and the abnormal expression of tlr4 (kim et al., 2017a (kim et al., , 2017b . in l02 cells, alantolactone (6) also inhibits oxldl-induced lipid accumulation trough regulating the apolipoprotein c3 (apoc3) expression partly by decreasing the activation of stat3 . thus, may be relevant to explore further its role in managing metabolic complications on e.g. modulating hepatic il-6/stat3 signaling in high-fat diet-induced metabolic disorder in animal models, since the physiological metabolic response to il-6 depends on the specific source of il-6 in vivo (han et al., 2020) concerning to in vivo experiments, no hypoglycemic effect was observed on stz-induced diabetic mice after oral administration of alantolactone. however, inflammation and renal abnormalities were suppressed via inhibition of nf-kb gene expression and the high glucose-induced overexpression of pro-inflammatory cytokines and macrophage adhesion in renal nrk-52e cells were inhibited. (zhu et al., 2020) . these results led the authors to propose a beneficial use for the treatment of diabetic neuropathy. taking together all evidences mentioned for alantolactone (6) activity, it is probably that this compound could reduce some components of mets by the regulation of inflammatory processes. alantolactone (6) did not induced significant hepatotoxicity and nephrotoxicity after daily administration (100 mg/kg b.w.) for 5 weeks in mice . this compound also is a contact allergen, and in vitro is cytotoxic in cancer cells and induces apoptosis (tisserand and young, 2014) . 6.6. 3,10-epoxygermacranolides from tithonia diversifolia (hemsl.) a. gray tithonia diversifolia (hemsl) a. gray, commonly known as tree marigold or mexican sunflower (asteraceae: heliantheae), is a shrublike perennial or annual invasive plant, native from north and central america. traditionally, its leaves are widely used by indigenous people for treating a wide spectrum of diseases, including diabetes mellitus. several in vitro and in vivo studies have stated the antioxidant antidiabetic, hypolipidemic and antiobesity effects of t. diversifolia (ajao and moteetee, 2017; tagne et al., 2018) . germacranolides, eudesmanolides and guaianolides are some of the major components occurring in this plant (ajao and moteetee, 2017; tagne et al., 2018) and because of their previously described activity, they apparently are involved in the important spectrum of bioactivity reported for t. diversifolia. tirotundin (7) and tagitinin a (8) (fig. 1) isolated from the ethyl acetate soluble fraction of t. diversifolia are related to the activation of peroxisome proliferator-activated receptors (ppars) (lin, 2012) . ppars are members of nuclear hormone receptors superfamily involved in the metabolic regulation of lipid and lipoprotein levels, blood glucose, and abdominal adiposity. in mammals, three isoforms of ppars have been recognized namely ppar-a, ppar-b/d and ppar-g. activation of ppar-a by hypolipidemic fibrate class of drugs decreases tg levels and raises hdl-c in dyslipidemic individuals, whereas activation of ppar-g by antidiabetic thiazolidinedione agents causes insulin sensitization to enhance glucose metabolism (botta et al., 2018) . currently, dual ppara/g agonists, which stimulate both ppara and ppar-g isoforms to similar extents, are gaining popularity since it is believed that they are able to ameliorate the unwanted side effects of selective ppar-a and ppar-g agonists; and may also be used to treat dyslipidemia and t2dm simultaneously (balakumar et al., 2019) . tirotundin (7) and tagitinin a (8) have been suggested being dual ppara/g agonists after the evaluation of their agonistic activity against ppars employing a transient transfection reporter assay in hepg2 cells . on the other hand, the germacranolides tagitinin g (9), tagitinin i (10), 1b-hydroxydiversifolin-3-o-methyl ether (11) and 1b-hydroxytirotundin-3-o-methyl ether (12) (fig. 1) isolated from the aerial parts of t. diversifolia were found to significantly elevate glucose uptake in 3t3-l1 adipocytes without any toxicity (zhao et al., 2012) . the authors suggested that these compounds had pparg agonist activity on glucose uptake, similar to pioglitazone, a ppar-g agonist used as a control compound in the study. no in vivo acute, subchronic or chronic toxicity studies on 3,10-epoxygermacranolides described above have been reported to date. the increasing abundance of tithonia diversifolia in conservation and agricultural areas over the past ten years in south africa has been of concern. this plant is considered as a scrub resulting in the initiation of a biological control program against its propagation (simelane et al., 2011) . therefore, utilization for medicinal purposes of this invasive plant could be important before major eradication takes place. the genus magnolia, previously known as michellia, reported to exert various biological effects, including anti-cancer, anti-anxiety, antidepressant, antioxidant and anti-inflammatory (lee et al., 2011) . in later years, magnolia species and their components have been related to ameliorate characters of obesity and diabetes, such as hyperglycemia, hyperlipidemia, and other complications . since terpenoids are one of the principal substantial compounds in magnolia species, slns may be related with its medicinal properties (sun et al., 2015) . anticancer activity investigation lead to the isolation of the guaianolide micheliolide (13) (fig. 1) from m. compressa (maxim.) sarg. (ogura et al., 1978) . this compound has also been obtained in a semi-synthetic way from a bf 3 -mediated rearrangement of parthenolide (castañeda-acosta et al., 1993; zhai et al., 2012) , presenting enhanced stability and remarkable antiinflammatory effect by suppressing activation of the nf-kb through inhibition of ikba degradation as well as for the inhibition of p65 translocation to the nucleus (viennois et al., 2014) . the compound also influenced the mapk and pi3k/akt signaling pathways in lpsstimulated bv-2 cells (sun et al., 2017) . further, an in vitro assay has revealed that 13 attenuate the high glucose-stimulated activation of nf-kb, the degradation of ikba, and the expression of mcp-1 in rat mesangial cells (jia et al., 2013) . in addition, the dimethylamino michael adduct of 13 known as dimethylaminomicheliolide is a pro-drug of this sesquiterpene lactone approved for clinical trials for glioblastoma treatment . this compound protects the kidneys against proteinuria, renal failure, histopathological injury, and inflammation by suppressing activation of the nf-kb signaling pathway in db/db mice . these results showed that dimethylaminomicheliolide intervention mitigated diabetic kidney disease in db/db mice without directly affecting hyperglycemia. furthermore, it has been demonstrated that micheliolide (13) alleviates hepatic steatosis in obese db/db mice, and the molecular mechanisms driving the therapeutic effects of this compound might involve ppar-g upregulation to consequently inhibit nf-kb mediated inflammation and activate ampk/mtor-dependent autophagy (zhong et al., 2018) . thus, it will be interesting to future work evaluate if this effect in hepatic steatosis impacts glucose metabolism. no in vivo toxicity studies on micheliolide (13) have been reported to date. byrsonima crassifolia (malpighiaceae), commonly known as "nanche", is a tropical tree widely distributed in mexico, central and south america. this tree is commonly harvested, both for its edible fruit and for its health benefits (b ejar and malone, 1993; duarte, 2011) . in folk medicine, the fruit or bark infusion have been used as hypoglycemic remedy (andrade-cetto and heinrich, 2005) and according to ethnomedicinal reports, the antihyperglycemic activity of hexane and chloroform extracts from fruits and seeds of b. crassifolia in stzinduced diabetic rats was reported (perez-gutierrez et al., 2010) . the phytochemical analysis of antihyperglycemic extract from the seed of b. crassifolia revealed that byrsonines a (14) and b (15) (fig. 2) , two dimeric guaianolides, are responsible for the antioxidant, hypoglycemic and hypolipidemic activities (guti errez and ramirez, 2016) . in particular, it has been proposed that the antihyperglycemic activity of these compounds may involve both pancreatic and extra pancreatic mechanisms, based on the observed increase in serum insulin level and the reduction of hepatic glucose output via decreasing glucose-6phosphatase (g6pase) activity and increasing glucokinase activity (guti errez and ramirez, 2016) . although the mechanisms underlying the antihyperglycemic activity of 14 and 15 have not been completely explored, this effect could likely be ascribed to the activation ampactivated protein kinase (ampk). activation of the ampk pathway in the liver regulates glucose homeostasis by inhibiting hepatic glucose production and downregulating the expression of gluconeogenic genes, including g6pase gene expression. targeting ampk by natural products demonstrated considerable success in lowering blood glucose levels (joshi et al., 2019) . nevertheless, more experimental research is needed to substantiate this claim. on the other hand, the induction of antioxidant enzymes in hepatic, renal, and pancreas tissues after the administration of 14 and 15, indicates a positive effect of these molecules in improving glycemic control in stz-induced diabetic rats (guti errez and ramirez, 2016), since oxidative stress takes an important role in the pathogenesis and progression of diabetic tissue injury. in this sense, the reported improvement in insulin resistance by byrsonines a and b can be related to the observed increase in the hdl-c levels and the decrease in tc, tg, ldl-c, and vldl (guti errez and ramirez, 2016). additionally, tnf-a levels were also decreased after treatment of byrsonines a and b in stz-induced diabetic rats. the bioactivity described for 14 and 15 makes them one of the most active guaianolides on different components of mets reported at this time. as described above, another molecule of this family with activity on different components of mets is eremathin. however, byrsonines a and b (14, 15) seems to be more effective, which could be due to their dimeric structure that provides two possible michaels acceptors. dimeric slns have been found to be more potently cytotoxic than their monomers toward human cancer cells, indicating that the antitumor potential of slns are improved by the presence of additional a-methylene-g-lactone ring (singh et al., 2011; ren et al., 2016) . this phenomenon could be studied in 14 and 15 for mets treatment due to their extended activity reviewed here. moreover, pharmacokinetics studies are needed to understand either byrsonines suffer biotransformation reactions and act as monomeric molecules or if they can show biological activity in their original dimeric forms. no in vivo toxicity studies on byrsonines a (14) and b (15) have been reported to date. various species of the genus lactuca are globally important edible plants containing valuable nutrients such as polyphenols, sterols, vitamins, minerals, and dietary fiber. l. sativa l., lactuca indica l. and l. serriola l. (syn. l. scariola l.) have been used in the treatment of diabetes mellitus, hypertension, and cardiac diseases (eddouks et al., 2002; subramoniam, 2016) . in vivo experiments of some lactuca species shown the ability to reduce several metabolic risk factors, especially hyperglycemia, tg and tc (nicolle et al., 2004; salih, 2019) . slns are commonly found in lactuca species and are represented as subgroups such as lactucin-type guaianolides and the eudesmanolide-type. the latter is commonly found in some species of lactuca such as l. sativa l. var. anagustata, l. saligna l. and l. canadensis l. (han et al., 2010; kisiel and gromek, 1993; michalska et al., 2013) . the dimeric guaianolide lactucain c (16) (fig. 2) , isolated from l. indica linn. showed moderate lowering of plasma glucose in stz-diabetic rats (hou et al., 2003) . nevertheless, there are no evidences about the possible mechanism of action and no further research has been made about this compound. as mentioned before, dimeric slns could show an important activity in components of mets derived from their double a,b-unsaturated g-lactone ring. because of its hypoglycemic properties and chemical structure, 16 is also a candidate to further studies that analyze deeply its effect in blood glucose levels and some other metss components. no in vivo toxicity studies on luctucain c (16) have been reported to date. 6.10. 8-deoxylactucin from cichorium intybus l cichorium intybus, commonly known as chicory, was historically cultivated by the ancient egyptians as a vegetable crop, a coffee substitute, and a medicinal plant. nowadays, it is appreciated for its bitter taste and widely used in india as a traditional treatment for diabetes mellitus (al-snafi, 2016; pushparaj et al., 2007) . the antidiabetic, hypolipidemic, hepatoprotective, antioxidant and anti-inflammatory effects of c. intybus have been widely studied (chandra and sk, 2016) . this broad spectrum of biological activities has been attributed to its high content of phytochemical constituents, being slns the most abundant in roots and the responsible of the bitterness of leaves (al-snafi, 2016). 8-deoxylactucin (17) (fig. 2) is a guaianolide found as a major component of chicory root and it is also common in species of lactuca. it has been demonstrated that 17 possess anti-inflammatory activity by inhibiting the nuclear transcription factor nf-kb and as a selective inhibitor of cox-2 (cavin et al., 2005 ). an important structural characteristic of 17 is the presence of a-methylene-g-lactone group and a,b-unsaturated cyclopentenone. compounds that possess these structures, such as helenalin, can react with sulfhydryl group of cys38 in nf-kb and prevent dna binding (lyß et al., 1998; widen et al., 2017) . thus, 8-deoxylactucin (17) could interact with nf-kb by a similar mechanism. no in vivo toxicity studies on 8-deoxylactucin (17) have been reported to date. 6.11. artemisinin from artemisia spp artemisinin (18) (fig. 2) is a cadinanolide endoperoxide sesquiterpene lactone originally isolated from artemisa annua linn in 1972 (tu, 2016) . nowadays, 18 and their derivatives are part of the protocols for malaria treatment (bridgford et al., 2018) . experimental studies have also established their effectiveness as an anti-inflammatory, antioxidant, anti-tumor, and vascular protection agent jiang et al., 2016; efferth, 2017) . regarding to vascular protection, cao et al. (2020) demonstrated that oral administration of artemisinin (18) effectively alleviated inflammatory response (mcp-1, ifn-g, il-6 and tnf-a), elevated macrophage autophagy, suppressed foamy macrophage transformation, and thereby inhibiting atherosclerotic plaque formation in high-fat diet treated apoe à/à mice. in addition, 18 has been discovered to be a potential therapeutic agent for ameliorating type 1 diabetes because of its ability to promote the conversion of pancreatic glucagon-producing a cells to insulinsecreting b cells in rats . nevertheless, the widespread application of artemisinin as an anti-malarial drug could contributed to the selection of resistant strains of the etiologic agent plasmodium, thus its use to combating non-communicable human diseases would raise the risk for this selection and lead to an important drug resistance development. some authors have suggested that unless necessary, artemisinin (18) should be replaced by other therapeutic agents for the treatment of versatile types of human diseases (dong-sheng et al., 2017) . it is important to note that some species of artemisia have been traditionally used in treatment of diabetes such as a. dracunulus l., a. minor jacq. ex besser, a. pallens wall. ex d.c., a. sphaerocephala krasch and a. herba-alba asso, (mohamed et al., 2010; subramoniam, 2016) . several eudesmanolides and guaianolides have been isolated from a. herba-alba, all of them having in common the absence of the a-methylene in the g-lactone ring as in artemisinin (18) structure. indeed the ethanol, chloroform and water extracts of this plant have showed important hypoglycemic activity (mohamed et al., 2010) . animal experiments show considerable toxicity after the application of artemisinin family (neurotoxicity, embryotoxicity, genotoxicity, hemato-and immunotoxicity, cardiotoxicity, nephrotoxicity, and allergic reactions), but large clinical studies and meta-analyzes did not show serious human side effects, although proper monitoring of adverse effects in developing countries may not be a trivial task. there is a paucity of large-scale clinical trials adequate to detect rare but significant toxicity. the lesson learned from animal and human studies is that long-term availability rather than short-term peak concentrations of artemisinin cause toxicity (efferth and kaina, 2010) . thus, the observation of the toxicity of artemisinin derivatives in animals, but not in humans, is most likely due to different pharmacokinetic profiles after different routes of administrations. 6.12. scoporanolide and estafiatin from artemisia scoparia waldst. & kit artemisia scoparia waldst. & kit. (redstem wormwood) is widely distributed in southwest asia and central europe. this species has been reported to possess anti-obesity (richard et al., 2014) and hypolipidemic (boudreau et al., 2018) properties. a. scoparia ethanolic extract reduces non-alcoholic fatty liver disease by enhancing hepatic insulin and amp-ampk signaling in diet-induced obese mice . a. scoparia hot water extract reduces blood pressure in spontaneously hypertensive rats via the inhibition of plasma angiotensin i-converting enzyme (ace) activity (cho et al., 2015) . the phytochemical analysis of this extract revealed that seven slns contribute to the antihypertensive effect inhibition of ace activity, highlighting the activity of scoporanolide (19) and estafiatin (20) (fig. 2) (cho et al., 2016) showing significantly higher ace inhibitory activities than the other isolated slns. no in vivo toxicity studies on scoporanolide (19) and estafiatin (20) have been reported to date. the guaianolide cumambrin a (21) (fig. 2) , isolated from chrysanthemum boreale (makino) makino, has shown a pharmacological effect on the normalization of blood pressure in spontaneously hypertensive rats (hong et al., 1999) . ex vivo study demonstrate that this compound is a potent relaxant of aortic smooth muscle at a concentration of 5 £ 10 à5 m (hong et al., 2005) . no in vivo toxicity studies on cumambrin a (21) have been reported to date. the potential beneficial effects of slns on metss risk factors discussed in this review clearly demonstrate that these substances represent remarkable compounds with a diversity of molecular structure and biological activity. these beneficial effects include normalization of blood glucose levels, improvement of blood lipid profiles, anti-inflammatory activity, improvement of insulin sensitivity and normalization of blood pressure. the underlying molecular targets mediating these effects have not been completely understood. regardless of that, it can be noticed that at least six molecular targets or pathways could explain the effect of slns on components of mets: furthermore, the evidence from published literature demonstrates that some slns belonging to guaianolides like eremanthin (4) and germacranolides such as costunolide (5) and guaianolide dimers byrsonines a and b (14, 15), show multifunctional benefits due to their action on many metss risk factors. these observations suggest that structural specificity may be a key for understanding the mechanisms of action of slns. looking forward, the effects of slns on mets should be explained based on the molecular targets and should be related to biochemical mechanisms. mets has become a major public health problem worldwide and represents a common clinical condition in countries with a high incidence of obesity and western dietary patterns. natural products, such as slns, are attractive drug candidates and more attention must be paid to their potential use in the treatment and prevention of mets. the authors declare no conflict of interest. sesquiterpene lactones with unusual structure. their biogenesis and biological activity evaluation of antidiabetic effect of methanolic extract of inula racemosa root in rats tithonia diversifolia (hemsl) a. gray. 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relevance essential oil safety. a guide for health care professionals, second ed artemisinin-a gift from traditional chinese medicine to the world (nobel lecture) micheliolide, a new sesquiterpene lactone that inhibits intestinal inflammation and colitis-associated cancer costus speciosus and coccinia grandis: traditional medicinal remedies for diabetes inula sesquiterpenoids: structural diversity, cytotoxicity and anti-tumor activity artemisia scoparia extract attenuates nonalcoholic fatty liver disease in diet-induced obesity mice by enhancing hepatic insulin and ampk signaling independently of fgf21 pathway targeting nf-kb p65 with a helenalin inspired bis-electrophile etiology of metabolic syndrome and dietary intervention alantolactone suppresses apoc3 expression and alters lipid homeostasis in l02 liver cells role of c-jun n-terminal kinase (jnk) in obesity and type 2 diabetes study of hypoglycaemic and hypolipidemic effects of inula viscosa l. aqueous extract in normal and diabetic rats jnk signaling: regulation and functions based on complex protein-protein partnerships biomimetic semisynthesis of arglabin from parthenolide three new sesquiterpenes from tithonia diversifolia and their anti-hyperglycemic activity extracts of magnolia species-induced prevention of diabetic complications: a brief review micheliolide alleviates hepatic steatosis in db/db mice by inhibiting inflammation and promoting autophagy via ppar-g-mediated nf-kb and ampk/mtor signaling alantolactone mitigates renal injury induced by diabetes via inhibition of high glucose-mediated inflammatory response and macrophage infiltration this work was partially supported by the secretaría de investigaci on y posgrado, instituto polit ecnico nacional. asg was cona-cyt (267721) and ipn-beifi fellow. julio c. ontiveros thanks conacyt for funding conacyt project no. 1069 "c atedras cona-cyt". key: cord-351932-dn60t7qa authors: salehi, bahare; sener, bilge; kilic, mehtap; sharifi-rad, javad; naz, rabia; yousaf, zubaida; mudau, fhatuwani nixwell; fokou, patrick valere tsouh; ezzat, shahira m.; el bishbishy, mahitab h.; taheri, yasaman; lucariello, giuseppe; durazzo, alessandra; lucarini, massimo; suleria, hafiz ansar rasul; santini, antonello title: dioscorea plants: a genus rich in vital nutra-pharmaceuticals-a review date: 2019 journal: iran j pharm res doi: 10.22037/ijpr.2019.112501.13795 sha: doc_id: 351932 cord_uid: dn60t7qa dioscorea species, known as “yams,” belong to family dioscoreaceae. this genus consists of more than 600 species distributed from africa, asia, the caribbean’s south america, and the south pacific islands. their organoleptic properties make them the most widely used carbohydrate food and dietary supplements. the underground and/or aerial tubers represent valuable sources of proteins, fats, and vitamins for millions of people in west africa. this review gives a shot of secondary metabolites of dioscorea plants, including steroids, clerodane diterpenes, quinones, cyanidins, phenolics, diarylheptanoids, and nitrogen-containing compounds. this review collected the evidence on biological properties of description dioscorea, including in-vitro and in-vivo studies. dioscorea species contain promising bioactive molecules i.e. diosgenin that support their different biological properties, including antioxidant, hypoglycaemic, hypolipidemic, antiantimicrobial, inflammatory, antiproliferative, androgenic, estrogenic, and contraceptive drugs. indeed, besides its nutrient values, dioscorea is a potential source of bioactive substances of interest in the prevention/treatment of several diseases, and thus represents a great challenge in developing countries. however, ethnomedicinal potential should be validated and further researches on pharmacological properties and phytochemical composition should be carried out. particularly, doing some studies to convert the preclinical results to clinical efficacy should be guaranteed. dioscorea, food plant, traditional use, phytochemistry, pharmacological activities dioscorea belongs to the family dioscoreaceae, sub-family dioscoreoideae, consisting of 600 species. dioscorea species are native to the old-world including high temperatures tropics and subtropic regions of the world. the major part of species occur in west africa, southern asia, and tropical america: they are herbaceous climbers with rhizome or tubers dioscorea species and, being usedin the formulation of pharmaceutical products, have a high medicinal, industrial and commercial importance (1) . indeed, dioscorea species account for the most important dietary supplements ingredients used in cosmetics and pharmaceutical industries. it has also been commonly used by local people, mostly those who are engaged in the trade of medical plants worldwide. indeed, tubers of different dioscorea species are used as a cure for different diseases and ailments (cough, cold, stomach ache, leprosy, burns, fungal infections, dysentery, skin diseases, rheumatism, arthritis, etc.) in several formulations, and even for birth control (1) . it is well known the potential of this plant is related due to the different phytochemical compounds found in dioscorea. tubers and roots contain steroidal sapogenins, mostly diosgenin as well as volatile compounds (2, 3) . chemical substances like diosgenin found in dioscorea are commercially used in the pharmaceutical industry. the high demand for the medicinal use of this plant in different parts of the world suggests a strong need for conservation strategies. however, the conservation might not be easy or simple as it must involve plant protection and wellcontrolled access to its resources. there still a huge need for more research and information on the food, nutraceutical, and medicinal value worldwide of this plant species. therefore, this review tends to fill this gap by summarizing data on the current medicinal importance of dioscorea species. researches have been brought new knowledge about chemical compounds in tubers of dioscorea species and possible medicinal usage. the most common secondary metabolites are saponins, and more than 100 steroidal saponins (based on aglycon part as stigmastanol, furostanol, spirostanol, cholestanol, ergostanol, and pregnanol glycosides (figure 1 )) were isolated from various dioscorea species. besides these steroids, clerodane diterpenes, phenolics, cyanidins, quinones, diarylheptanoids, and nitrogen-containing compounds in the tubers of dioscorea species were quantified (4) . steroidal saponins mainly consist of furostane, a pentacyclic ring system with a sixth open ring; spirostane, a hexacyclic ring system; and pregnane, a tetracyclic ring system. the sugar part is mainly composed of glucose and rhamnose in various proportions and linkages. steroidal saponins are glycosides consisting of an aglycone (diosgenin) and several glycosyl moieties. the most common sugars encountered in saponins are pentoses (arabinose, xylose, etc.), hexoses (glucose, galactose, etc.) and 6-deoxyhexose (rhamnose, etc.). the saponins of this plant species are both water-soluble and water-insoluble steroid saponins. dioscorea species are well known for containing steroidal saponins, which were used as marker compounds for quality control of the botanical products. as reported by jesus et al., 2016 , diosgenin (3-β-hydroxy-5spirostene) is the primary furostanol saponin found in several plants, including dioscorea species, and is described as a promising bioactive compound with several medicinal properties, i.e. hypolipidemic, antioxidant, anti-inflammatory, hypoglycaemic, and antiproliferative activities (5) . diosgenin obtained by hydrolysis of yam saponin were the main raw material for the industrial production of steroid drug i.e. anti-inflammatory, androgenic, estrogenic, and contraceptive drugs, by underlying its potential in the prevention/treatment of several diseases. dioscorea villosa l. roots and rhizomes, also are known as "wild yam", is a rich source of diosgenin. today, dietary supplements containing wild yam extracts are popular among women for the alleviation of menopausal symptoms and are widely used as alternatives to hormone replacement therapy (5) . dioscorea alata l. dioscorea alata l. is one of the most popular varieties of yams. dioscorea alata (d. alata) were implicated in the promotion of the health of postmenopausal women. wild mexican yam was marketed for the treatment of irritability, hot flashes, insomnia, and depression. cheng et al., 2007 , reported the isolation and identification of two new compounds, hydro-q 9 chromene, and γ-tocopherol-9; together with four known compounds (rrr-α-tocopherol, coenzyme q 9 , cycloartane, and 1-feruloylglycerol): these compounds had phenolic hydroxyl group in common with the known phytoestrogens and have also antioxidant activity. moreover, their estrogenic activity was evaluated based on the ligand-dependent transcription activation assay (6) . dioscorea antaly jum. and h. perrier is originated from madagascar, diffused in the west and north-west regions. the study of rakatobe et al., 2010 reported two clerodane diterpenoids, antadiosbulbins a and b and two furanoid 19-norclerodane diterpenes, 8-epidiosbulbins e and g along with the known diterpenoid diosbulbin e as well as nine known phenolics including five phenanthrenes and four flavonoids in the ethyl acetate soluble part of the methanolic extract of the tubers (7) . dioscorea bulbifera l. dioscorea bulbifera l. (d. bulbifera l.), commonly known as air potato, is originated from africa and southern asia. the rhizome of d. bulbifera l. is called as "huang yao zi" in traditional chinese medicine and used for the treatment of thyroid diseases and cancers. in the northern districts of bangladesh, this herb is used for the treatment of cancers and leprosy. this plant has two types of storage organs, namely bulbils in the leaf axils of the stem and tubers. bulbils have been used as a folk remedy to treat diarrhea, conjunctivitis, and the extracts of the plant exhibit anti-tumor activity. the mannose-binding lectin from bulbils of d. bulbifera was studied for its clinical potential in hiv and cancer research (8) . phytochemical studies reported as main bioactive compounds of this plant: flavonoids, clerodane diterpenoids, and steroidal saponins and phenolic compounds. as instance, liu et al. 2011 reported the isolation and identification of two new compounds, bibenzyl type-2,5,2′,5′-tetrahydroxy-3′methoxybibenzyl and diarylheptanone containing a dihydrophenanthrene moiety named as diobulbinone a along with sixteen known compounds (9) . nine norclerodane diterpenoids were isolated from the tubers of d. bulbifera l. including two new compounds (diosbulbin n and diosbulbin p), and a naturally occurring compound (diosbulbin o) along with six known diosbulbins a-d, f, and g (10) . another study also showed the molecular changes of liver dysfunction and reveal overall metabolic and physiological mechanisms of the subchronic toxic effect of dioscorea bulbifera rhizome (11) . lam.-holl known as "yellow yam" is native to tropical west africa and its rhizomes are used as food and as a remedy for treating burns and fevers. a new furostanol glycoside namely 26-o-β -d-glucopyranosyl-3β,26-dihydroxy-20,22-seco-25(r)-furost-5en-20,22-dione-3-o-α-l-rhamnopyranosyl-(1→4)-α -l-rhamnopyranosyl-(1→4)-[ α -l -r h a m n o p y r a n o s y l -( 1 → 2 ) ] -β -dglucopyranoside was isolated from the methanolic extract of the rhizome of dioscorea cayenensis growing in cameroon, together with the known spirostanol saponins described as methyl protodioscin, asperoside and prosapogenin a of dioscin (12) . prosapogenin a of dioscin having a spirostan skeleton showed antifungal activity against candida species with mic values between 6.25 and 25 mg/ml (12) . two new fatty acidspirostan steroid glycoside esters, progenin iii palmitate, and progenin iii linoleate, were isolated from the methanol extract of the rhizomes of dioscorea cayenensis (13) . it is worth mentioning the recent studies on the nutrient and antinutrient composition of yellow yam (dioscorea cayenensis) and their products; as instance raw dioscorea cayenensis tubers contained 66.79 g moisture, 2.62 g crude protein, 0.27 g lipid, 0.17 g fiber, 0.63 g ash, 29.69 g carbohydrates, 262.30 mg potassium, 61.53 mg magnesium, 0.79 mg iron, 0.39 mg zinc, and yielded 108.26 kcal energy with insignificant vitamin content/100 g edible portion (14) . dioscorea esculenta (lour.) burk. dioscorea esculenta also called as a "lesser yam" of dioscorea species, is widely distributed southern asia and the pacific. the tubers of d. esculenta were used traditionally in the treatment of various diseases. moreover, fiteen steroidal saponins were isolated from its tuber powder, and from the leaf of dioscorea esculenta (d. esculenta); four of them belonged to furostanol-type saponin,eleven as spirostane-type saponins (15) . the rhizome of dioscorea japonica thunb., known as "san yak" in korea, is used as food and medicine. the plant was used in traditional chinese medicine to control/eliminate diarrhea, dilute sputum, improve anorexia, and moisturize skin (16) . phytochemical studies on dioscorea japonica (d. japonica) showed the presence of active hypoglycemic compounds (dioscorans a-f), sesquiterpene, and acetophenone along with the steroidal constituents, including spirostane, furostane, and cholestane types (16) . the rhizomes of dioscorea membrancea (d. membranacea) pierre have been used in thai traditional medicine. as instance, thongdeeying et al. 2016 isolated from the cytotoxic chloroform fraction of the rhizomes a new steroid (epi-panthogenin b), a known steroid (panthogenin b), two napthofuranoxepins dioscorealide a and dioscorealide b, phenanthraquinone (dioscoreanone) and three phenanthrene; the same authors reported that also, three steroids (β-sitosterol, stigmasterol, and β-dsitosterolglucoside) and two steroidal saponins [(diosgenin-3-o-α-l-rhamnopyranosyl (1→2)-β-d-glucopyranoside and diosgenin-3 -o -β -d -g l u c o p y r a n o s y l ( 1 -3 ) -β -dglucopyranoside)] were obtained from d. membranacea (17) . makino is bitter-sweet in taste and warm in nature according to the traditional chinese medicine. the rhizomes of d. nipponica were traditionally used in china as herbal medicine and food supplement for more than four thousand years; particularly, these plant species mainly act on the liver, kidney, and lungs, displaying anti-rheumatic, analgesic, blood circulation-stimulating, lung channeldredging, digestive, anti-diuretic, anti-tussive, panting-calming, and phlegm-dispelling activities. medicinally, it is commonly used for the treatment of rheumatoid arthritis, pain in the legs and lumbar area, kashin-beck disease, bruises, sprains, chronic bronchitis, cough and asthma and communication, and adherence to therapy is one of the main concerns (4, 18 and 19) . recently, it has been used as an important industrial raw material for the synthesis of steroidal drugs. concerning the phytochemical profile, twelve cyclic diarylheptanoids were isolated from the rhizomes of dioscorea nipponica (20) , among which two new cyclic diarylheptanoids, diosniponol a and b; moreover, as reported by the same authors, these compounds were evaluated for their effects on nitric oxide production without cell toxicity in lipopolysaccharide-activated bv-2 cells. therefore, diarylheptanoid derivatives from d. nipponica may be potential candidates for the treatment of various neurodegenerative diseases associated with neuroinflammation (20) . another study described the watersoluble non-saponin components [benzyl 1-o-β-d-glucopyranoside, leonuriside a, icariside d2, pyrocatechol-1-o-β-dglucopyranoside, (+) syringaresinol-4-oβ-d-glucopyranoside, cyclo-(leu-tyr), and adenosine], and phenolic acid (piscidic acid) from the rhizomes of d. nipponica (21) . on the other hand, 7-oxodioscin a new spirostan-type steroid along with known dioseptemloside g, (25r)-dracaenoside g, orbiculatoside b, dioscin, progenin iii, gracillin were determined. the presence of (3β,22α,25r)-26were also confirmed as furastan-type steroids (21) . it is worth mentioning the study of that explore the chemical basis of the rhizomes and aerial parts of dioscorea nipponica makino by a combination of cheminformatics and bioinformatics, particularly their potential therapeutic and toxicity targets were screened through the drugbank's or t3db's chemquery structure search: the compounds in the rhizomes possessed 391 potential therapeutic targets and 216 potential toxicity targets (22) . dioscorea opposita thunb. dioscorea opposita thunb. has been cultivated in china, japan, and korea as a food, and widely used as traditional medicine, for a very long time. there are about 80 yam cultivars that are originated in china, including the so-called "trueborn" chinese yam. the important ingredient of the yam is sugar, which provides energy and sweetness and adds to the general flavor of foods. also, the chinese yam assists in food digestion and is beneficial in cases of stomach disorders (23) . phytochemical investigations of dioscorea opposite (d. opposita) have revealed many chemical components such as purine derivatives, phenanthrenes, stilbenes, sapogenins, and saponins. phytochemical studies of the chloroform soluble fraction of d. opposita thunb. have resulted in the isolation of four new compounds, two dihydrostilbenes: 3,5-dihydroxy-4-methoxybibenzyl, 3,3′,5trihydroxy-2′-methoxybibenzyl; and dibenzoxepins 10,11-dihydro-dibenz[b,f]oxepin-2,4diol and 10,11-dihydro-4-methoxy-dibenz[b,f] oxepin-2-ol, together with an additional fifteen known compounds. all the nineteen isolated compounds were tested in the dpph, superoxide anion radical scavenging assays and cyclooxygenases (coxs) inhibition assay. among them, 3,3′,5-trihydroxy-2′methoxybibenzyl showed the most potent cox-2 inhibitory activity (23) . bioassayguided fractionation of d. opposita extracts led to the isolation and identification of 23 phenolic compounds. of them, 15 compounds reduced porcine pancreatic lipase activity at ic 50 values of less than 50 mm and from them 3,3′,5-trihydroxy-2′-methoxybibenzyl and (4e,6e)-1,7-bis(4-hydroxyphenyl)-4,6-heptadien-3-one showed the highest inhibition with an ic 50 value of 8.8 mm and dose-dependently in the concentration range 5-100 mm (24) . these findings provide that phenolic compounds with stilbenoids are considered to play important roles in the lipase inhibition of the d. opposita extract. especially, the stilbenoids possessing 3,5-dihydroxybibenzyl moiety showed higher inhibitory potencies than the others. the lipase inhibitory activities of stilbenoids depend on the presence of the hydroxyl group in the c-3 position. the structural difference also influences the inhibitory effect of diarylheptanoids on pancreatic lipase. dihydrostilbene phenanthrene and diarylheptanoid structures were deemed to be responsible for lipase inhibition activity of this species (24) . d. opposita thunb. is also rich in starch, water-soluble polysaccharides, and mucilage defined as a polysaccharide with unique viscosity characteristics are widely used in the pharmaceutical and food industries as a thickening agent and emulsion stabilizer. these agents are important in the food industry as they improve the sensory quality, flavor, texture, palatability, mouthfeel, and general appearance of the final products. therefore, the mucilage of this plant species is a potential candidate for food emulsifier resource of a natural emulsifier, especially under alkaline conditions obtained from industrial processing waste such as gum arabic, yellow mustard, and chia (salvia hispanica l.) (25) . dioscorea preussii pax d. preussii pax collected in bambui, cameroon, was reported to have in-vitro cytotoxic, antileishmanial and antifungal activities. three new steroidal saponins, named as diospreussinosides a, b, c, along with two known compounds were determined as (25r)-17α-hydroxyspirost-5r h a m n o p y r a n o s y l -( 1 → 4 )α -l -r h a m n o p y r a n o s y l -( 1 → 4 ) ] -β -dglucopyranoside were isolated from rhizomes of d. preussii (27) . dioscorea pyrifolia kunth d. pyrifolia kunth is called also as "akar kemeyan paya" in malaysia. these plants grow wild and are diffused particularly in peninsular malaysia. sharlina et al. 2017 reported that the starch extracted from d. pyrifolia was characterized by the high amylose content (44.47 ± 1.86%); the same authors marked how d. pyrifolia kunth represents a very important source of starch for food and non-food applications, such as crispy food, coating materials, hydrogels, films, bio-membranes, and adhesives (28) . cholestane glycosides, dioseptemlosides a and b, together with six spirostane glycosides, dioseptemlosides c-h, were isolated from the rhizomes of d. septemloba. among these, spirostane aglycones containing hydroxyl group at c-7 were reported in the family dioscoreaceae. spirostane-type glycosides showed strong activity on nitric oxide production (29) . on the other hand, three new diarylheptanoids, dioscorol a, dioscorosides e 1 , e 2 ; two new stilbenes, dioscorosides f 1 and f 2 were isolated from the rhizomes of dioscorea septemloba. besides, 1,7-bis(4-hydroxyphenyl)hepta-4e,6e-dien-3-one, 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one, 3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane, (3r,5r)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane 3-o-β-d-glucopyranoside, (3r,5r)-3,5-dihydroxy-1,7-bis(4-hydroxywere also obtained as known compounds. they have also shown a significant increase in the glucose consumption in differentiated l6 myotubes and displayed triglyceride inhibitory effects in hepg2 cells . eight new compounds namely, dioscorosides g, h1, h2, dioscorol b, dioscorosides i, j, k1, and k2, together with twelve known ones were isolated from the rhizomes of dioscorea septemloba. moreover, the authors showed that some of these compounds were found to display significant inhibition of nitrite production evaluated in-vitro anti-inflammatory potential using lps-stimulated raw 264.7 murine macrophages (30) . currently, he et al. 2019 have identified and elucidated the structure of a new phenanthropyran, dioscorone b, and a new phenanthrene, together with seven known compounds, is from the 75% ethanol extract of dioscorea septemloba rhizomes. moreover, the authors reported that new isolated phenanthropyran, tested for antioxidant activity, showed excellent activities with ic 50 values of 0.07 ± 0.10 μm and 0.13 ± 0.09 μm, respectively (31). dioscorea tokoro makino d. tokoro is one of those wild yams, and its rhizome was generally used for daily food.; in particular in the northern part of japan, the rhizome was used as health-promoting food. d. tokoro was characterized by steroidal saponins, such as dioscin and gracillin, but no data were found about its health-promoting effect. the acetonitrile extract of d. tokoro rhizome fractionation led to protodioscin as an antiproliferative compound to hl-60 leukemic cells (32) . the most well-known species of this genus is dioscorea villosa, also called "wild yam." two furanostane type saponins, namely methyl parvifloside, and protodeltonin, were isolated from d. villosa as well as two spirostane types deltonin and glucosidodeltonin (zingiberensis i), whereas minor saponins were methylprotodioscin, disoscin, and prosapogenin (33) . the same authors reported that two fla-van-3-ol glycosides were also isolated from d. villosa and fifteen steroidal compounds, including two new metabolites, were isolated from the tubers of d. villosa; these compounds were characterized as cholestane type steroidal glycosides named as dioscoreavillosides a and b (33). dong et al., 2012 described how the rhizomes were also afforded 14 diarylheptanoids, five of which were new compounds containing a tetrahydropyran ring in the heptane portion of the molecule (34) . in another study, three furostanol saponins, parvifloside, methyl protodeltonin, and trigofoenoside a-1 were isolated from the n-butanol soluble extract of d. villosa by using hsccc; moreover the authors reported that subsquent normal-phase hsccc separation also led to the identification of four spirostanol saponins identified as zingiberensis saponin i, deltonin, dioscin, and prosapogenin a of dioscin (35) . on the other hand, two series of lipidated steroid saponins were isolated from d. villosa (36) . the series a was identified as a mixture of five lipidated steroid saponins: the series b was characterized as a mixture of the following five compounds: 5-en-clionasterthese findings revealed two classes as new biomarkers: the diarylheptanoids and the lipidated steroid saponins. the rhizome of dioscorea zingiberensis c.h. wright is known as ''huang jiang" and represents an important source of diosgenin. d. zingiberensis were used for the treatment of lung heat, pyretic stranguria, anthracia, coronary heart disease, and swelling; in particular, the rhizome of dioscorea zingiberensis is extensively used for the extraction of diosgenin sapogenin and its glycoside dioscin, used for the synthesis of sex hormones and corticosteroids. it is worth mentioning the current study of zhang et al., 2018 that give comprehensive overview of the traditional usage and phytochemistry of the dioscorea zingiberensis c.h. wright: -more than 70 compounds have been identified; -several of these have been tested in preclinical assays and clinical trials; -a wide spectrum of biological effects including cardiovascular, anti-thrombosis, hyperlipidemia, neuroprotection, anti-inflammatory, and anthelmintic effect has been verified (37) . wang et al. 2010 reported how spirostanol based aglycon containing steroidal saponins are the representative steroidal saponins, and their quantity is higher than that of furostanol steroidal saponins in d. zingiberensis (38) . apart from the steroidal saponins, other kinds of constituents were also identified from d. zingiberensis. until now, four steroids have been isolated from this plant including β-sitosterol, sterol, zingiberenin f, and (25r)-3β-hydroxyspirost-δ5,20 (21) in addition to the common steroidal saponins, other constituents classified as alkaloid, phenyl-glycoside, and benzoic acid derivatives have also been determined. 4-aminomethyl-phenol, 2-o-β-d-glucopyranosyl-4-hydroxybenzoic acid and another nonsteroidal saponin called 2-o-β-d-glucopyranosyl-4-methoxybenzoic acid, were isolated and identified from the n-buthanol extracts of fresh rhizomes. following the regular phytochemical research procedure, five compounds were obtained from d. zingiberensis (38) . they consisted of two new phenanthrene derivatives, namely 2,5,7-trimethoxy-1,4-dione-9,10-dihydrophenanthrene and 2,5,6-trihydroxy-3,4-dimethoxy-9,10-dihydrophenanthrene; a new anthracenedione, i.e., 2,5,7-trimethoxy-1,4-dione-anthracene; and two known 9,10-dihydrophenanthrenes, called 5,6-dihydroxy-2,4-dimethoxy-9,10-dihydrophenanthrene and 2,5-dihydroxy-3,4,6-trimethoxy-9,10-dihydrophenanthrene. one new bibenzyl (3,5-dihydroxy-4,40-dimethoxybibenzyl.) and one new phenanthrene (2,5-dihydroxy-4,6-dimethoxy-9,10-dihydrophenanthrene.), together with two known bibenzyls (3,5-dihydroxy-4-methoxybibenzyl 3,5′,-dihydroxy-3′,4-dimethoxybibenzyl and four known diarylheptanoids ((3r,5r)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane, (3r,5r)-3,5-dihydroxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)heptane, (3r,5r)-3,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-heptane and (3r,5r)-3,5-dihydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)-heptane were isolated from the dichloromethane soluble fraction of the rhizomes of d. zingiberensis (39) . all these phenolic compounds were evaluated for their anti-pancreatitic activities on sodium taurocholate-induced pancreatic acinar necrosis as inhibition of necrotic cell death pathway activation. among them, (3r,5r)-3,5-dihydroxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl) heptane which bears a trihydroxy-diarylheptane skeleton was shown to protect against pancreatic acinar cell injury through mediating novel potential therapy for pancreatic necrosis (39) . the tubers of different dioscorea species present a wide variation of bioactive compounds, responsible for their pharmacological activities. generally, the evaluation of bioactive components and the assessments of their interactions could be viewed as the first step for the determination of potential of a plant (40) (41) (42) (43) (44) (45) (46) . also, their ethnopharmacological importance promotes further investigations of dioscorea metabolites as a source of potential therapeutic agents to ameliorate different diseases (table 1) . cytotoxic activity d. bulbifera ethanolic crude extract and different fractions (hexane, ethyl acetate, and water) at concentrations of 50, 100, and 200 μg/ml were found to possess a potent cytotoxic activity against human colorectal carcinoma (hct116), human colorectal adenocarcinoma (ht-29), human lung carcinoma (a549), human breast carcinoma (mcf-7), human tuber immune-modulating activity (54) . anti-inflammatory activity (55) anti-severe acute respiratory syndrome associated coronavirus (56) . gastroprotective activity (57) enhance murine splenocyte proliferation ex-vivo and improve regeneration of bone marrow cells (58) immunomodulatory activity (59) anti-inflammatory activity (55) . neuroprotective activity (82) antioxidant activity (83) mediated synthesis of gold and silver nanoparticles with catalytic activity (84) neuroprotective activity (82) antidiabetic activity (85) cell shrinkage, and dna fragmentation as shown by flow cytometry. the authors also revealed that dbeaf induces apoptosis effects on hct116 cells through externalization of phosphatidylserine and by promoting the loss of mitochondrial membrane potential (mmp), dysregulation of the bcl-2 family proteins and the downregulation of the expression of procaspase -8, -9, -10 and -3 and parp protein expression. furthermore, their results suggested that the inhibitory effect of dbeaf on erk1/2 and the activation of jnk were closely associated with the apoptotic cell death induction in human colorectal carcinoma (60). rhizome antioxidant activity (86) antitumor activity (81) anti-hypercholesterolemic effect (87) anti-platelet aggregation activity (87) antifungal activity (88) antihyperlipidemic and antioxidative activity (81) dioscorea pentaphylla l. antioxidant activity and antibacterial activity d. collettii var. hypoglauca and its active metabolite protoneodioscin, a furostanol saponin, was also evaluated for its cytotoxic activity against 60 cell lines including human leukemia, melanoma, and cancers of lung, colon, brain, ovary, renal, breast, and prostate. protoneodioscin exhibited significant cytotoxicity with 50% growth inhibition (gi 50 ) ranging from 0.5 to 9 mm against all cell lines from leukemia and most solid tumors (64) . in the following year, the same research team evaluated two other compounds, namely; methyl protoneogracillin and gracillin. the results revealed that methyl protoneogracillin exhibited significant cytotoxicity with (gi 50 ) ≤ 2 mm. leukemia, cns cancer, and prostate cancer were the most sensitive subpanels, while ovarian cancer was the least sensitive subpanels. on the other hand, gracillin lacked selectivity against human cancer diseases (29). a different approach was undertaken by ashri and co-workers (2018) (71), who evaluated the cytotoxicity of modified d. hispida starchbased hydrogels on small intestine cell line (fhs-74 int) to ensure the safety of their use. their results revealed that the prepared hydrogels did not show any cytotoxicity and could be employed for future pharmaceutical use. a mucopolysaccharide of yam (d. batatas decne) (ymb) was found to increase the cytotoxic activity of mouse splenocyte against leukemia cell at 10 µg/ml concentration. however, it did not affect the viability of splenocytes. the production of ifn-γ was significantly increased in the ymp treated splenocytes. at 50 µg/ml concentration, it increases the up taking capacity and lysosomal phosphatase activity of peritoneal macrophages. in addition, ymp (10-100 µg/ml) significantly increased the viability of peritoneal macrophages (54) . dioscorin, the glycoprotein isolated from d. alata was reported to activate toll-like receptor 4 (tlr4) and induce macrophage activation via typical tlr4-signaling pathways at 100 µg/ml concentration. it induces tlr4downstream cytokine expression in bone marrow cells isolated from tlr4-functional c3h/hen mice but not from tlr4-defective c3h/hej mice. dioscorin also stimulated multiple signaling molecules (nf-jb, erk, jnk, and p38) and induced the expression of cytokines (tnf-a, il-1b, and il-6) in murine raw 264.7 macrophages (47) . different dioscorea species were used traditionally for the treatment of memoryrelated disorders and dementia, i.e. alzheimer disease and other neurodegenerative diseases (82) . the chloroform extract from d. opposite rhizomes significantly reduced the glutamateinduced toxicity in a dose-dependent manner with a maximum neuroprotective effect at 10 µg/ml (82) . kim (16) . moreover, the compounds isolated from d. nipponica rhizomes exhibited anti-neuroinflammatory and neuroprotective activities, the most active of which was 3,7-dihydroxy-2,4,6trimethoxy-phenanthrene. the later was the most potent nerve growth factor (ngf) inducer, with 162.36% stimulation, and strongly reduced nitric oxide (no) levels with an ic 50 value of 19.56 μm in lps-activated bv2 microglial cells. also, it significantly increased neurite outgrowth in mouse neuro2a (n2a) cells and therefore possessed a significant neuroprotective activity (76) . antidiabetic activity different extraction procedures as ultrasonic-assisted extraction, cold water extraction, warm water extraction and hot water extraction significantly influenced the antidiabetic potential of the rhizomes of d. hemsleyi as determined via both alphaglucosidase and alpha-amylase inhibition assays, where the ic 50 values of alphaglucosidase inhibition assay varied from 27.41 to 274.36 µg/ml while those of alpha-amylase inhibition assay varied from 3.66 to 47.57 mg/ ml (70) . the antioxidant activity of the extracts of dioscorea species received much scientific attention (67, 72, 73 and 83) . different extracts of rhizomes of d. hemsleyi, d. hispida dennst, d. opposite thunb., d. nipponica makino, d. esculenta (lour). burkill, d. japonica thunb. var. pseudojaponica and d. pentaphylla l. were all studied for their antioxidant properties by different in-vitro assays namely; reducing power assay, ferric reducing antioxidant power assay (frap), dpph radical scavenging assay, hydroxyl radical scavenging assay, superoxide radical assay, self-oxidation of 1,2,3-phentriol assay and antioxidant activity by radical cation (abts) assay. generally, the studied extracts from different dioscorea species showed a significant antioxidant potential which may account for their involvement in the treatment of various disorders via radical scavenging mechanisms. lipopolysaccharide-stimulated raw 264.7 cells were employed to determine the antiinflammatory properties of the ethanolic extract of tubers of d. japonica thunb. var. pseudojaponica and individual steroid glycosides isolated from d. septemloba rhizomes (29, 73) . d. japonica extract at doses of 500 and 1000 µg/ml significantly inhibited lps-induced inos and cox-2 protein expressions, also, the nitrite relative concentration percentage ranged between 11.3% to 107.5% for the steroid glycosides isolated from d. septemloba rhizomes. similar to the total ethanol extract of d. membranacea presented a potent inhibitory activity, with an ic 50 value of 23.6 µg/ml. its most potent metabolite included diosgenin-3-o-alpha-lrhamnosyl (1-->2)-beta-d-glucopyranoside that showed a powerful inhibitory activity with ic 50 value as low as 3.5 µg/ml (74) . the study of the mechanism of anti-inflammatory activity of the ethanolic extract from the bark of d. batatas decne showed that it inhibited both no and pge2 production with an ic 50 of 87-71 µg/ml respectively. it was also suggested that the extract act suppressing dna-binding activity and reporter gene activity as well as translocation of the nf-jb p65 subunit. it also down-regulated ijb kinase (ikk), thus inhibiting lps-induced both phosphorylation and the degradation of ijba. in addition, it also inhibited the lps-induced activation of erk1/2 (55) . a current study of hwang et al. 2019 reported the anti-inflammatory effect of aerial bulblets of dioscorea japonica thunb extract through inhibition of nf-κb and mapk signaling pathway in raw 264.7. antiallergic activity d. membranacea ethanolic extract and compounds showed antiallergic activities by inhibiting beta-hexosaminidase release as a marker of degranulation in rbl-2h3 cells, with an ic 50 value of 37.5 µg/ml. from this extract, dioscorealide b showed the highest activity with an ic 50 value of 5.7 µg/ml (77) . du et al. 2017 reported how several compounds were isolated from the rhizomes of d. zingiberensis i.e. (3r,5r)-3,5-dihydroxy-1-(3,4-dihydroxyphenyl) -7-(4-hydroxyphenyl) heptane at a concentration of 0.5 mm showed anti-pancreatitis activities on sodium taurocholate -induced pancreatic acinar necrosis with an inhibitory effect of 19.0%. moreover, the same authors marked that this compound's protective effects were mainly dependent on atp inhibition and excessive ros production and thus saving the cells from mitochondrial dysfunction (39) . another study reported that the steroidal saponins obtained from the rhizomes of d. zingiberensis showed anti-arthritic activities on the lps stimulated 264.7 macrophage cells through induction of both p65 and iκbα protein expressions (98) . the methanolic extract of tubers of d. pentaphylla l. showed antibacterial activity against s. pyogenes, s. mutans, v. cholera, s. typhi, and s. flexneri. the best activity was: 19.00 mm and 16.00 mm inhibition zone diameter observed (at 50 μg/disc and 200 μg/ disc) against s. pyogenes using disc diffusion, agar well diffusion assays, respectively. the mic values were 100 μg/ml for the extract against v. cholera, s. typhi and s. flexneri while it was 50 μg/ml against s. pyogenes and s. mutans. similarly, rajendra et al. reported the antibacterial activities of 5% and 10% methanolic extract of d. deltoidea wall ex griseb rhizomes against s. aureus and e. coli, but this concentration does not show activity against s. typhi and p. aeruginosa. it could be concluded that, in general, dioscorea species do not exhibit a potent antibacterial activity (86) . the study of cho et al. 2013 studied dioscin, isolated from wild yam d. nipponica root bark, for its potential as an antifungal agent via the propidium iodide assay and calceinleakage measurement, in addition to, its ability to disrupt the plasma membrane potential, using 3,3′-dipropylthiadicarbocyanine iodide and bis-(1,3-dibarbituric acid)-trimethine oxanol. as reported by cho et al. 2013 the results showed that dioscin exerts a considerable antifungal activity, where, the dye-stained cells showed a significant increase in fluorescent intensity after treatment with dioscin, demonstrating that dioscin possess an effect on the membrane potential. the auhors concluded that dioscin could act by disrupting the fungal membrane structure resulting in cell death (99) . globally a large number of dioscorea plants have investigated in-vivo. data on dioscorea species potency on the animal model are summarized in table 1 . the anti-constipation activity dioscorea opposita thunb. yam tuber is rich in starch, which has always been ignored and discarded during the isolation of bioactive compounds. huang et al., 2016 studied the anti-constipation effect of native yam starch (ns), dual enzyme-treated starch (des), and cross-linked carboxymethyl starch (ccs) in constipation model induced by loperamide in km mice. the modified starches (des and ccs) could benefit the bowel function by increasing stool frequency and defecation moisture as they have the good water-binding capacity and swelling ability, the modified starches could increase the water-holding capacity of stools to remain soft. des and ccs groups had improved small intestinal propulsion through the production of more short chain fatty acids (scfas) and decrease ph by increasing acetic acid and butyric acid concentration in the feces. the study done on mice with high-fat diet showed that both native and modified starch from yam had anti-hyperlipidemic activity through a significant decrease of both cholesterol and triglycerides and the liver index. the reduction of superoxide dismutase (sod) and increase malondialdehyde (mda) was observed in hyperlipidemic mice while they were both improved in all starches-treated mice proving their antioxidant effect (table 1 ) (100). four types of resistant starch (rs) including native (rs2), retrograded (rs3), crosslinked with sodium trimetaphosphate/sodium tripolyphosphate (rs4) and complexed with palmitic acid (rs5) resistant starches from winged yam (d. alata l.) showed the gastroprotective activity of in ethanol-induced gastric ulcer in mice. the increase in gastric emptying rate may help in reducing the contact time of ethanol and gastric mucosa and helps to prevent the gastric tissue damage. therefore, an increase in gastric emptying induced by rs is a possible mechanism of anti-gastric ulcer. moreover, rs3 and rs5 groups generated more short chain fatty acids which are produced through fermentation of the starch by the colon microflora. the fatty acids have many physiological and biological functions, such as increasing the immunity of the stomach. etoh-ulcer can result from the imbalance between the generated reactive oxygen species (ros) and the natural antioxidant power. thus, the free radical scavenging is one of the mechanisms for inhibition of gastric ulcer (101). mao et al. 2018 reported the decrease of sod activity in ethanol-treated rats with an increase in mda levels in gastric mucosa indicating severe oxidation reaction in ethanol-induced gastric ulcer mice. rs3 (6.4 g/kg) and rs4 (6.4 g/kg) exhibited the best antioxidant effect. therefore, the inhibition of oxidative stress by the four types of rs is a possible mechanism that may assist in decreasing the gastric mucosal damage. generally, the high dose groups of rs3 and rs5 (6.4 g/kg) showed the best activity (50) . a current study also reported the protective effects of dioscorea batatas flesh and peel extracts against an ethanol-induced gastric ulcer in mice (57) . li et al. 2010 reported the significant antithrombotic and anticoagulation effect of the total steroidal saponin extract (tsse) from the rhizomes of d. zingiberensis c.h. wright on inferior vena cava ligation thrombosis rat model and pulmonary thrombosis mice model. oral administration of the extract significantly inhibited adenosine diphosphateinduced platelet aggregation (pag) in-vivo, which was more effective than xue-sai-tong, a commercial product of triterpenoid saponins from panax ginseng having antithrombosis activity in china. in addition, tsse inhibited the thrombosis in a dose-dependent manner (more than 50% inhibition rate) which was more powerful than the standard xue-saitong at 64.7, and 129.4 mg/kg doses of tss, and markedly reduced thrombus weight. tsse also exhibited in a dose-dependent manner prolongation of thromboplastin time (aptt) (which is an intrinsic clotting index), prothrombin time (pt) (that evaluates the extrinsic clotting pathway), and thrombin time (tt) (which is a test of fibrin formation, the addition of thrombin directly induces that). the more pronounced effect of tsse on pt and tt than aptt indicates that it inhibits the extrinsic pathway of coagulation and fibrin formation, and cut down the thrombotic risk (102) . the ethanolic extract of the tubers of d. japonica thunb. var. pseudojaponica (eedj) showed in-vivo anti-inflammatory activity by significantly inhibiting the development of carrageenan-induced paw edema in mice after the 4th and 5 th hour of the treatment at 1.0 g/kg. it also decreased the levels of tnf-α, which is a mediator of carrageenan-induced inflammatory response and induced the release of kinins and leukotrienes. carrageenaninduced paw edema causes oxidative stress with the release of peroxidation products, including malondialdehyde (mda) and nitric oxide. mda increased levels of oxygen free radicals, which attack polyunsaturated fatty acids in cell membranes and causing lipid peroxidation. eedj was able to reduce nitric oxide which was excessively released after administration of carrageenan and also could reduce the levels of mda through increasing the enzymatic antioxidant defense systems such as catalase (cat), superoxide dismutase (sod) and glutathione peroxidase (gpx) in the paw oedema which are the natural protectors against lipid peroxidation (73) . the anti-arthritic effect of the total saponin extract from the rhizomes of d. zingiberensis c.h. wright (tsrdz) in freund's complete adjuvant (fca) induced arthritis in rats (98) . in this study, a significant increase in arthritis scores and ankle perimeter were observed after 4 days from intraplantar administration of fca, which reaches its maximum on day 16. administration of tsrdz at 100 and 200 mg/kg produced substantial dose suppressive significant effect in the treated groups. tsrdz at 100 and 200 mg/kg also caused a marked reduction of fca-induced elevated indexes of the thymus and spleen. the high dose of tsrdz caused only mild synovial infiltration with few inflammatory cells and no obvious damage in cartilage bone erosion, which appeared in histopathological study. the efficient regulation of tsrdz on the inflammatory cytokines at 200 mg/ kg, was almost equivalent to that caused by the standard methotrexate. moreover, the mitigation of tsrdz on the prostaglandins (pge2), at 200 mg/kg, was almost equivalent to that of standard methotrexate. furthermore, administration of tsrdz at 200 mg/kg resulted in attenuating the production of mda and no, while elevating the sod activity compared with the control group (98) . the total 80% ethanol extract of the tubercles of d. trifida l.f. as well as its three subfractions, dichloromethane, butanol, and aqueous fractions showed anti-inflammatory activity in food allergy induced by ovalbumin in balb/c mice (94) . ova-sensitized balb/c mice received the ova solution to develop local signs of inflammation characterized by eosinophil infiltration, edema, an increase in a number of mast cells in the intestinal submucosa, mucus secretion, an increase in serum anti-ova igg1 and ige, and weight loss because of hyper-catabolism caused by the production of inflammatory cytokines. the crude extract of d. trifida tested at the doses of 100 and 300 mg/kg/day corresponding to 36.6 and 109.8 mg/kg/day of allantoin, and 3.0 and 9.0 mg of diosgenin correlated substances/kg/ day, respectively did not affect the body weight, but they inhibited ige production compared to untreated groups. the inhibition tended to be more significant in aqueous fraction and butanol fraction, which contains allantoin, than dichloromethane, which contains diosgenin. the ethanolic extract and its fractions exerted a reduction in several mastocytes and edema, which was also probably due to the presence of diosgenin and allantoin (94) . diosgenin was also reported to reduce the production of anti-ova ige and the inflammatory infiltrate in allergic balb/c mice intestines, resulting in a reduction in edema (103) . balb/c mice having food allergy showed an increase in mucus production by the caliciform cells in the small intestine (104) . an important allergic response that is induced by interleukins il-4 and il-3 is hypersecretion of mucus. mucus has a protective effect on the intestinal cells by limiting the antigen absorption. the presence of eosinophil peroxidase (epo) indirectly reflects the infiltration of eosinophils into intestinal mucosa, which was reduced by administration of the ethanolic extract of d. trifida. mollica et al. also showed that d. trifida extract and fractions reduced all of the inflammatory parameters associated with food allergies in ova-sensitised animals and this activity is correlated with the presence of allantoin and diosgenin correlated substances (94) . the animals treated with ethanolic extract showed a reduction in mucus production, and this result was also observed for the other fractions. previous studies showed that diosgenin and allantoin activities reduce mucus production in animals allergic to ova (103) . the crude extracts of d. membranaceae and d. birmania, which contain high amounts of sapogenins, inhibited the production of nitric oxide (no) most probably through inhibiting the nitric oxide synthetase (inos) and tnf-α, with consequent reduction of intestinal edema (74, 77) . a study by olayemi and ajaiyeoba also associated the antiedematogenic activity of crude extract from d. esculenta to the presence of sapogenins (105) . in-vivo studies have demonstrated that oral administration of allantoin attenuates the production of ige, il-4, and il-5, has an anti-inflammatory effect and promotes healing (68) . the methanol extract of the rhizomes of d. deltoidea wall.ex griseb. at 200 mg/ kg inhibited the rat hind paw carrageenaninduced edema. the maximum percentage of inhibition was achieved at 3 h after the intraperitoneal administration of the extract (106) . in a study made by yang et al., the chloroform soluble extract of the rhizomes of d. opposita (csdo) showed cognitive enhancing effects on spatial memory and learning function of mice against scopolamineinduced amnesic deficits via morris water maze and passive avoidance tests. in morris water maze test, both acute treatment by csdo (200 mg/kg body weight, p.o.) and prolongedtreatment (10 days' daily administration of 50 mg/kg body weight, p.o.) exhibited significant shorter escape latencies in daily first trial than the scopolamine-administered group during a 4-consecutive-day training period, which suggested that csdo improves the impaired reference memory (long-term memory) induced by scopolamine. especially, the acute treatment group showed a marked decrease in escape latencies in each daily trial compared with the prolonged treatment group. in this study, csdo also showed significant enhancing effects on spatial memory retention in the probe trial. similar results were obtained in the passive avoidance test. csdo treatment significantly increased step-through latencies of scopolamine-induced amnesic mice compared to control untreated group. the results of the two animal behavioral tests demonstrated that csdo improves spatial learning and memory function against scopolamine-induced amnesia (82) . the study of jeon et al., 2014 investigated the neuroprotective effect of herbal mixture from euphoria longana, houttuynia cordata, and dioscorea japonica, by testing the hypothesis that administration of herbs reverses memory deficits and promotes the protein expression of brain-derived neurotrophic factor (bdnf) in the mouse brain: these herbs demonstrated an inductive effect on bdnf, cyclic-amp response element-binding protein (creb) and phospho-creb (pcreb) (107) . the study of the antinociceptive effect of the methanol extract of the bulbs of dioscorea bulbifera l. var sativa (medb) was performed by nguelefack et al. (2010) the effects of medb persisted for 5 days after two administrations in cfa-induced hypernociception at 250 and 500 mg/ kg. medb significantly inhibited acute lipopolysaccharides (lps)-induced pain at 500 mg/kg but did not affect thermal hypernociception and capsaicin-induced spontaneous nociception. the antinociceptive effects of medb in prostaglandin-e2 (pge2) model was antagonized by either nitro-l-arginine methyl ester (l-name) or glibenclamide. this indicated that the plant exerted its antinociceptive effect through partial activation of the no-cgmp-atpsensitive potassium channels pathway (62) . the intraperitoneal administration of n-butanol extract of the d. nipponica rhizomes at 50 mg/kg regulates the blood cholesterol, triglyceride, hdl and ldl than the chloroform (50 mg/kg) and water extracts (50 mg/kg) (80) . wang et al. 2012 reported the potential activity of trillin, a steroidal saponin isolated from d. nipponica rhizomes, as antihyperlipidemic and anti-oxidative agent invivo. the intraperitoneal administration of trillin (0.5 mg/kg dissolved in 0.5% dmso) enhanced the blood circulation and could increase the bleeding time for more than 50% and coagulation in the rats fed on a high-fat diet in which the blood viscosity would be changed resulting in shorter blood coagulation time. the improvement effect of trillin in restoring the blood coagulation abnormality in high-fat diet fed rat was due to its ability to reduce the levels of blood cholesterol, triglyceride and two critical lipoproteins (hdl and ldl). the level of lipid oxidation was increased in high-fat diet rats, causing oxidative stress. trillin exerted an anti-oxidative effect through lowering lipid peroxidation, via the enhancement of superoxide dismutase (sod) level in blood. thus, the combination of trillin and lovastatin in treating hyperlipidemia could represent a more effective therapy (wang et al. 2012 ). the authors of this research marked how these findings greatly support the significant role of d. nipponica in protecting the cardiovascular system in-vivo against hyperlipidemia (80). tang (87); the authors reported how high serum levels of lactate dehydrogenase (ldh), aspartate aminotransferase (ast) and creatine kinase (ck) indicated cell membrane damage and were thus elevated in the iso model group. intra-gastric injection of total saponins of the three species could restore the activities of myocardial injury marker enzymes to the same extent. oxidative stress plays an essential role in the pathogenesis of mi injury. sod, catalase (cat), gpx, and total antioxidant capacity (t-aoc) levels were reduced significantly in the iso model group with the increase in mda. the activities of these enzymes were normalized by intragastric injection of the total saponins of the three species. the study revealed that the anti-mi mechanism of dioscorea saponins is related not only to the enzymatic antioxidant, such as gpx and cat but also to nonenzymatic antioxidants and its effect on myocardial histology (87) . the current studies reported the beneficial effects of purple yam (dioscorea alata l.) resistant starch on hyperlipidemia in high-fat-fed hamsters (108, 109) . the total saponins from rhizoma dioscoreae nipponicae could effectively reverse potassium oxonate-induced alterations in renal mouse urate transporter 1, glucose transporter 9, organic anion transporter 1, and organic anion transporter 3mrna and protein levels, resulting in enhancement of renal urate excretion in mice (79) . moreover, the authors concluded that the total saponins from rhizoma dioscoreae nipponicae had a uricosuric effect on the regulation of renal organic ion transporters in hyperuricemic animals. in a further paper, the same authors here was the potent uricosuric effect of tdn on hyperuricemic rats by decreasing the expressions of renal rurat1 while increasing the expressions of renal roat1 and roat3 (78) . a double-blind, placebo-controlled, crossover study was conducted to evaluate the effects of a wild yam cream in 23 healthy women suffering from troublesome symptoms of the menopause. every female was treated with the active cream and a placebo for 3 months randomly. after 3 months treatment with topical wild yam extract in women suffering from menopausal symptoms it was found that the cream is free from side-effects, and has little effect on menopausal symptoms (110) . dioscorea species make a significant contribution both as root crops and vegetables to the diets around the world. despite their importance as a food source, dioscorea plant parts are quite useful in the treatment of various ailments and disorders due to the presence of several bioactive compounds such as diosgenin. however, several reported ethnomedicinal potential need to be validated and detailed investigations on dioscorea pharmacological properties and phytochemical composition should be carried out to standardize the formulations used. indeed, some pharmacological properties such as hypolipidemic, hypoglycaemic, antioxidant, anti-inflammatory, antimicrobial, antiproliferative, androgenic, estrogenic, and contraceptive have been reported. however, most of the active constituents have not been characterized. thus, authentication of all the secondary metabolites (alkaloids, saponin, flavonoids, tannins, and phenols) from dioscorea should be performed thoughtfully to standardize and validate its quality and biological potentials. moreover, investigations are warranted to address the poor conversion of the preclinical results to clinical efficacity. therefore, an attempt should be made to understand their mechanism of action, pharmacokinetics/pharmacodynamics, and bioavailability and to conduct clinical trials. overall, these findings suggested that dioscorea should not be ignored and should rather be considered as a good alternative source of active molecules that can prevent or alleviate both functional and infectious disease burden, representing a current big challenge in developing countries. the knowledge gaps in this review such as insufficient data on a clinical trial to support preclinical results will help the further initiative to turn dioscorea into drug and stimulate activity to promote their production and utilization as not only valuable components of a well-balanced diet but also for disease prevention. dioscorea spp. (a wild edible tuber): a study on its ethnopharmacological potential and traditional use by the local people of similipal biosphere reserve volatile compounds in intermittent frying by gas chromatography and nuclear magnetic resonance volatile components of the rhizomes of dioscorea japonica dioscorea nipponica makino: a systematic review on its ethnobotany, phytochemical and pharmacological profiles diosgenin: recent highlights on pharmacology and analytical methodology isolation and identification of novel estrogenic compounds in yam tuber (dioscorea alata cv clerodane and 19-norclerodane diterpenoids 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from dioscorea pyrifolia tubers anti-inflammatory steroids from the rhizomes of dioscorea septemloba thunb bioactive constituents from the rhizomes of dioscorea septemloba thunb a new phenanthropyran and a new biphenanthrene from the rhizomes of dioscorea septemloba and their antioxidant activities protodioscin, isolated from the rhizome of dioscorea tokoro collected in northern japan is the major antiproliferative compound to hl-60 leukemic cells cholestane steroid glycosides from the rhizomes of dioscorea villosa (wild yam) diarylheptanoids from dioscorea villosa (wild yam) application of high-speed countercurrent chromatography-evaporative light scattering detection for the separation of seven steroidal saponins from dioscorea villosa lipidated steroid saponins from dioscorea villosa (wild yam) an overview on its traditional use, phytochemistry, pharmacology, clinical applications, quality control, and toxicity anthelmintic activity of steroidal saponins from dioscorea zingiberensis 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peel extracts against ethanol-induced gastric ulcer in mice dioscorea phytocompounds enhance murine splenocyte proliferation ex-vivo and improve regeneration of bone marrow cells in-vivo immunomodulatory effects of phytocompounds characterized by in-vivo transgenic human gm-csf promoter activity in skin tissues dioscorea bulbifera induced apoptosis through inhibition of erk 1/2 and activation of jnk signaling pathways in hct116 human colorectal carcinoma cells phytochemistry and therapeutic potential of medicinal plant: dioscorea bulbifera antinociceptive activities of the methanol extract of the bulbs of dioscorea bulbifera l. var sativa in mice is dependent of no-cgmp-atp-sensitive-k+ channel activation the cytotoxicity of protoneodioscin (nsc-698789), a furostanol saponin from the rhizomes of dioscorea collettii var. hypoglauca, against human cancer cells invitro the cytotoxicity of methyl protoneogracillin (nsc-698793) and gracillin (nsc-698787), two steroidal saponins from the 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dioscorea zingiberensis ch wright in freund's complete adjuvant induced arthritis in rats the antifungal activity and membranedisruptive action of dioscin extracted from dioscorea nipponica preparation, physicochemical characterization and biological activities of two modified starches from yam novel role of zn (ii)-curcumin in enhancing cell proliferation and adjusting proinflammatory cytokine-mediated oxidative damage of ethanolinduced acute gastric ulcers anti-thrombotic activity and chemical characterization of steroidal saponins from dioscorea zingiberensis ch wright diosgenin attenuates allergen-induced intestinal inflammation and ige production in a murine model of food allergy a model of chronic ige-mediated food allergy in ovalbumin-sensitized mice anti-inflammatory studies of yam (dioscorea esculenta) extract on wistar rats anti-inflammatory and antimicrobial property of dioscorea deltoidea l from nepal alteration in brain-derived neurotrophic factor (bdnf) after treatment of mice with herbal mixture containing euphoria longana, houttuynia cordata and dioscorea japonica the beneficial effects of purple yam (dioscorea alata l.) resistant starch on hyperlipidemia in high-fat-fed hamsters the beneficial effects of purple yam (dioscorea alata l.) resistant starch on hyperlipidemia in high-fatfed hamsters effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women key: cord-353815-w35spqqt authors: huan, yuchen; kong, qing; mou, haijin; yi, huaxi title: antimicrobial peptides: classification, design, application and research progress in multiple fields date: 2020-10-16 journal: front microbiol doi: 10.3389/fmicb.2020.582779 sha: doc_id: 353815 cord_uid: w35spqqt antimicrobial peptides (amps) are a class of small peptides that widely exist in nature and they are an important part of the innate immune system of different organisms. amps have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses. the emergence of antibiotic-resistant microorganisms and the increasing of concerns about the use of antibiotics resulted in the development of amps, which have a good application prospect in medicine, food, animal husbandry, agriculture and aquaculture. this review introduces the progress of research on amps comprehensively and systematically, including their classification, mechanism of action, design methods, environmental factors affecting their activity, application status, prospects in various fields and problems to be solved. the research progress on antivirus peptides, especially anti-coronavirus (covid-19) peptides, has been introduced given the covid-19 pandemic worldwide in 2020. alexander fleming discovered lysozyme in 1922, and this discovery marked the birth of modern innate immunity. since then, antibiotics and antimicrobial peptides (amps) have been discovered. a total of 3,240 amps have been reported in the antimicrobial peptide database (apd3 1 ) updated on august 24, 2020. different types of amps have the following commonalities: their number of amino acid residues is between 10 and 60 (average: 33.26), and almost all amps are cationic (average net charge: 3.32). however, several anionic amps also exist, and they have several acidic amino acids like aspartic acid and glutamic acid (malkoski et al., 2001; schittek et al., 2001; lai et al., 2007) . the anti-microbial resistance of microorganisms is becoming increasingly serious with the abuse of antibiotics in medicine, agriculture and animal husbandry, especially in developing countries. research from kenya has detected substantial amounts of antibiotic residues in edible meat (ayukekbong et al., 2017) . the prevalence of vancomycin-resistant enterococcus (vre) and methicillin-resistant staphylococcus aureus (mrsa) is increasing in clinical medicine, so the countermeasures are urgently needed to address these bacterial infections. however, from the 1 http://aps.unmc.edu/ap/ perspective of pharmaceutical companies, the development of new antibiotic drugs results in low profit. thus, replacing antibiotics has become a consideration in the pharmaceutical, agricultural, animal husbandry, and food industries. research on amps is continuously developing and considerable amounts of data on amps have been stored in amp databases. however, the mechanism of amps remains incompletely understood, and further work needs to be performed to determine the relationship between different physicochemical properties to obtain low-cost and highly safe amps with remarkable antimicrobial effects and the specificity and a high capacity for synergies of amps should also be further developed (lazzaro et al., 2020) . the diversity of natural amps causes difficulty in their classification. amps are classified based on (1) source, (2) activity, (3) structural characteristics, and (4) amino acid-rich species (figure 1 ). the sources of amps can be divided into mammals (human host defense peptides account for a large proportion), amphibians, microorganisms, and insects according to statistical data in apd3. the amps found in oceans have also attracted widespread attention. mammalian antimicrobial peptides are found in human, sheep, cattle, and other vertebrates. cathelicidins and defensins are the main families of amps. defensins can be divided into α-, β-, and θ-defensins depending on the position of disulfide bonds (reddy et al., 2004) . human host defense peptides (hdps) can protect human from microbial infections but show different expressions in every stage of human growth. for example, cathelicidin ll-37, a famous amp derived from the human body, is usually detected in the skin of newborn infants, whereas human betadefensin 2 (hbd-2) is often expressed in the elderly instead of the young (gschwandtner et al., 2014) . hdps can be identified in many parts of the body such as skin, eyes, ears, mouth, respiratory tract, lung, intestine, and urethra. besides, amps in human breast milk also play an important role in breastfeeding because it can decrease the morbidity and mortality of breastfeeding infants (field, 2005) . what's interesting is that casein201 (peptide derived from β-casein 201-220 aa), identified in colostrum, shows different levels in preterm human colostrum and term human colostrums . dairy is an important source of amps, which are generated through milk enzymatic hydrolysis. several amps have been identified from α-lactalbumin, β-lactoglobulin, lactoferrin, and casein fractions, and the most famous peptide obtained is lactoferricin b (lfcinb) (sibel akalın, 2014) . furthermore, whether the amps derived from dairy products can be used for dairy preservation is also an interesting subject to develop. in addition to antimicrobial activity, hdps, such as cathelicidins and defensins, also affect immune regulation, apoptosis, and wound healing (wang, 2014) . antimicrobial peptides from amphibians play an important role in the protection of amphibians from the pathogens that have induced the global amphibian population decline (rollins-smith, 2009 ). frogs are the main source of amphibian amps and the most famous amp from frogs is magainin; the skin secretions of frogs from genera xenopus, silurana, hymenochirus, and pseudhymenochirus under the pipidae family are rich in amps (conlon and mechkarska, 2014) . furthermore, cancrin, which has an amino acid sequence of gsaqpykqlhkvvnwdpyg, has been reported as the first amp from the sea amphibian rana cancrivora (lu et al., 2008) . this marks a broader source of amps of amphibians. figure 1 | classification of antimicrobial peptides. (semreen et al., 2018) . myticusin-beta is an immune-related amp of mytilus coruscus and a promising alternative to antibiotics (oh et al., 2020) . moreover, ge33, known as pardaxin, is a marine amp and the ge33-based vaccine has shown the ability to enhance antitumor immunity in mice (huang et al., 2013) . the activity of amps can be divided into 18 categories according to the statistics of the adp3 database. these categories can be summarized as antibacterial, antiviral, antifungal, antiparasitic, anti-human immunodeficiency virus (hiv), and anti-tumor peptides (figure 2 ). antibacterial peptides account for a large part of amps and have a broad inhibitory effect on common pathogenic bacteria, such as vre, acinetobacter baumannii, and mrsa in clinical medicine and s. aureus, listeria monocytogenes, e. coli in food and salmonella, vibrio parahaemolyticus in aquatic products. many natural and synthetic amps like nisin, cecropins and defensins have shown good inhibition activity to gram-positive bacteria and gram-negative bacteria. in recent research, amps p5 (yirkirrffkklkkilkk-nh 2 ) and p9 (syerkinrhfktlkknlkkk-nh 2 ), which are designed based on aristicluthys nobilia interferon-i, inhibit mrsa and show a low cytotoxicity . antifungal peptides are a subclass of amps that address fungal infections with enhanced drug resistance. many afps have shown excellent anti-fungal activities against common pathogenic fungi, such as aspergillus and candida albicans in clinical medicine, yeast, filamentous fungi (e.g., aspergillus flavus), mold in food and agriculture. except for brevinin, ranatuerin, cecropins, many synthetic peptides also show good antifungal activity. for example, aurh1, derived from aurein 1.2, can effectively treat c. albicans infection, which has a lethal rate up to 40% (madanchi et al., 2020) . aflatoxin, which is a carcinogen produced by a. flavus, is harmful to the human body. many afps can inhibit the growth of a. flavus. for example, an afp with a sequence of fpshtgmsvppp can inhibit the growth of a. flavus md3. a total of 37 antifungal peptides isolated from lactobacillus plantarum te10 and their mixture can reduce a. flavus spore formation in fresh maize seeds (muhialdin et al., 2020) . moreover, two chemically synthesized radish amps show a good inhibitory effect against different yeast species, such as zygosaccharomyces bailii and zygosaccharomyces rouxii (shwaiki et al., 2020) . viruses cause serious harm to human life and huge economic losses to the animal husbandry. the covid-19, which is the recent outbreak, has caused great loss of lives and properties. furthermore, foot-and-mouth disease virus, avian influenza virus (aiv), and hiv are long-term threats to human life. so, it is extremely urgent to solve these problems, and antiviral peptides provide new ways. antiviral peptides show a strong killing effect on viruses mainly by (1) inhibiting virus attachment and virus cell membrane fusion, (2) destroying the virus envelope, or (3) inhibiting virus replication (jung et al., 2019 ) (shown in figure 3 ). a recent report has shown that amp epi-1 mediates the inactivation of virus particles and has good inhibitory activity against foot-and-mouth disease virus . moreover, infectious bronchitis virus (ibv) is the pathogen of infectious bronchitis and the inoculation of swine intestinal amp (siamp)-ibv mixed solution remarkably reduced the mortality of chicken embryos compared with the ibv infection group, showing the good inhibitory activity of siamp on ibv (sun et al., 2010) . anti-hiv peptides are a subclass of anti-viral peptides. the most important examples of these peptides include defensins (including αand β-defensins, which have different mechanisms), ll-37, gramicidin d, caerin 1, maximin 3, magainin 2, dermaseptin-s1, dermaseptin-s4, siamycin-i, siamycin-ii, and rp 71955 (madanchi et al., 2020) and antiviral peptide fuzeon tm (enfuvirtide) has been commercialized as an anti-hiv drug (ashkenazi et al., 2011) . due to the global spread of the covid-19 (figure 4a ), the antiviral peptides against the coronavirus will be discussed in more detail. coronaviruses (covs) belong to the family coronaviridae; they are enveloped viruses with a positive-sense single-stranded rna genome and have a helical symmetry (franks and galvin, 2014) . covs, including severe acute respiratory syndrome cov (sars-cov) and middle east respiratory syndrome coronavirus (mers-cov) (mustafa et al., 2018) , and the recent outbreak of covid-19 have caused serious threats to human life and property. covs can cause lifethreatening respiratory diseases and the viral particle is formed by spike glycoprotein (s), the envelope (e), the membrane (m), and the nucleocapsid (n) (vilas boas et al., 2019) . it should be noted that their infectivity requires viral spike (s) protein. fusion inhibitor peptides combine with the s protein to interfere with its folding and prevent infection. besides, the s2 domain of the sars-cov s protein contains heptad repeat hr1 and hr2 sequences. peptide hr2 (hr2: sltqinttlldltyemlslqqvvkalnesyidlkel) and its lipid-binding peptide is highly similar or even identical to the near-membrane portion of s protein ferredoxin, which interferes with refolding into post-fusion fusion-catalyzing domains (fds) (du et al., 2009; park and gallagher, 2017) . according to recent research, the lipopeptide ek1c4, derived from ek1 (sldqinvtfldleyemkkleeaikkleesyidlkel), is the most effective fusion inhibitor against covid-19 s proteinmediated membrane fusion . homology modeling and protein-peptide docking showed that temporin has potential therapeutic applications against mers-cov (marimuthu et al., 2019) . two amps from the non-structural protein nsp10 of sars-cov, k12, and k29, can inhibit sars-cov replication (ke et al., 2012) . furthermore, rhesus thetadefensin 1 (rtd-1) treated animals have a marked reduction in mortality in the presence of sars-cov while the peptide alone shows airway inflammation and the one possible mechanism of action for rtd-1 is immunomodulatory (wohlford-lenane et al., 2009) . in general, amps against coronavirus can be roughly classified as i) peptides derived from hr1, hr2 and rbd subunits of the spike protein, ii) peptides derived from other amps, iii) peptides derived from non-structural protein (mustafa et al., 2018) . furthermore, molecular docking analysis indicated that peptides were employed to disrupt the interaction between covid-19 and ace2 (angiotensin-converting enzyme 2) to inhibit covid-19 entrance in cells ( figure 4b ) (souza et al., 2020) . finally, it should be noted that this therapy lacks clinical trials and the main method of animal experiments is an intranasal administration. this reminds us that nasal drug delivery (ndd) is a potential therapy for amps as anti-coronavirus drugs. besides, the antiviral database avpdb 2 includes numerous antiviral peptides. parasitic protozoa can cause diseases in human and animals through a variety of routes, including animal-to-person or person-to-person contact, water, soil, and food (chalmers et al., 2020) . and with the increase in parasite drug resistance, the need for new treatments has increased. antiparasitic peptides show their killing effect on parasites which cause diseases such as malaria and leishmaniasis (mangoni et al., 2005; rhaiem and houimel, 2016) and amps like cathelicidin, temporins-shd show high inhibition activity against parasites (abbassi et al., 2013) . in recent research, epi-1, a marine synthetic amp, can remarkably inhibit trichomonas vaginalis by destroying its membrane (neshani et al., 2019) . the peptide jellein derived from bee royal jelly which has introduced above and 4-amino acid amp kdel (lysine, aspartic acid, glutamic acid, and leucine) has shown a significant effect on the leishmania parasite (cao et al., 2019; zahedifard et al., 2020) . however, it should be noted that their mechanisms are not the same. cyanobacterial peptides differ from higher-eukaryote amps because their antiparasitic action depends on specific protein targets. thus, these target parasites can be distinguished accurately even though they belong to the same family or genus (rivas and rojas, 2019) . the acps show anticancer mechanisms by (1) recruiting immune cells (such as dendritic cells) to kill tumor cells, (2) inducing the necrosis or apoptosis of cancer cells, (3) inhibiting angiogenesis to eliminate tumor nutrition and prevent metastasis, and (4) activating certain regulatory functional proteins to interfere with the gene transcription and translation of tumor cells (wu d. et al., 2014; ma et al., 2020) . tritrpticin and its analogs induce considerable toxicity toward jurkat cells in vitro, whereas indolicidin and puroindoline a can also act as acps (arias et al., 2020) . it should be noted that both net charge and hydrophobicity play important roles in optimizing the anticancer activity of acps and they can constrain and influence each other. thus, achieving a balance between net charge and hydrophobicity is important for better anticancer activity. besides the peptide mentioned above, anti-inflammatory, anti-diabetic peptides, spermicidal peptides etc. have been noticed, but they are not the same as antimicrobial peptides. simply put, anti-inflammatory peptides decrease the release of inflammatory mediators and inflammatory cytokines (nitric oxide, interleukin-6, and interleukin-1β) and some of them also inhibit inflammatory signals like nf-κb, mapk, and jak-stat pathways (meram and wu, 2017; gao et al., 2020) . anti-diabetic peptides play their function by modulating the g proteincoupled receptor kinase (grk 2/3) or activating glucagonlike peptide-1 (glp-1), glucagon receptors (marya et al., 2018; graham et al., 2020) . however, it is not accurate to classify these types of peptides as amps and bioactive peptides may be more convincing. proline is a typical non-polar amino acid. pramps behave differently from other amps, that is, they enter bacterial cytoplasm by the inner membrane transporter sbma instead of killing bacteria through membrane destruction (mattiuzzo et al., 2007) . once in the cytoplasm, pramps target ribosomes and block the binding of aminoacyl-trna to peptidyltransferase center or trap decoding release factors on the ribosome during the termination of translation to interfere with protein synthesis (seefeldt et al., 2015) . for instance, tur1a, which is an orthologous amp of bovine pramp bac7 discovered from tursiops truncatus, interferes with the transition from the initial phase to the extension phase of protein synthesis by binding to ribosomes. in addition, different pramps lack a high sequence similarity but have short motifs containing repeating proline and arginine (arg) residues (e.g., -ppxr-in bac5 and -prpxin bac7) (mardirossian et al., 2018 (mardirossian et al., , 2019 . although pramps mainly kill gram-positive bacteria, ppr-amp1, a proline-rich amp identified from crab (scylla paramamosain), exhibits antimicrobial activity against gram-positive and gram-negative bacteria (imjongjirak et al., 2017) . besides, pieces of research have shown that pramps have immunostimulation activity (li w. et al., 2016) . tryptophan (trp), as a non-polar amino acid, has a remarkable effect on the interface region of the lipid bilayer, whereas arg, as a basic amino acid, confers peptide charge and hydrogen bond interactions, which are essential properties to combine with the bacterial membrane's abundant anionic component. and it seems that trp residues play the role of natural aromatic activators of arg-rich amps by ion-pair-π interactions (walrant et al., 2020) , thereby promoting enhanced peptide-membrane interactions (chan et al., 2006) . in addition to indolicidin and triptrpticin which both are famous amps that rich in arg and trp residues. octa 2 (rrwwrwwr) is also a typical trp-and arg-rich amp that inhibits gram-negative e. coli and pseudomonas aeruginosa and gram-positive s. aureus. and short trp-and arg-rich amps designed based on bovine and murine lactoferricin have also shown strong inhibitory action against bacteria (strøm et al., 2002; bacalum et al., 2017) . histidine is a common basic amino acid, and histidine-rich amps show good membrane permeation activity. hv2 is a histidinerich amp designed based on rr(xh) 2 xdpgx(yh) 2 rr-nh 2 (where x represents i, w, v, and f). this peptide increases the permeability of bacterial cell membranes to cause cell membrane rupture and death. in addition, hv2 inhibits bacterial movement in a concentration-dependent manner and shows a strong anti-inflammatory effect by inhibiting the production of tumor necrosis factor α (tnf-α) ). an amp designed based on octa 2 has shown good therapeutic potential by replacing its arg residues with histidine (bacalum et al., 2017) . furthermore, l4h4, which is designed based on the linear cationic amphiphilic peptide magainin, also shows good antibacterial activity and cell penetration properties by inserting four histidine sequences in leucine and alanine (lointier et al., 2020) . the r group of glycine is generally classified as a non-polar amino acid in biology. glycine-rich amps, such as attacins and diptericins, widely exist in nature (lee et al., 2001; kwon et al., 2008) . these peptides contain 14% to 22% glycine residues, which have an important effect on the tertiary structure of the peptide chain. a glycine-rich amp derived from salmonid cathelicidins activates phagocyte-mediated microbicidal mechanisms, which differ from the mechanism of conventional amps (d'este et al., 2016) . furthermore, the glycine-rich central-symmetrical gg3 is an ideal commercial drug candidate against clinical gramnegative bacteria . antimicrobial peptides can be divided into four categories based on their structures including linear α-helical peptides, β-sheet peptides, linear extension structure, and both α-helix and β-sheet peptides ( figure 5 ) (lei et al., 2019) . moreover, progressively cyclic peptides and amps with more complex topologies (including lasso peptides and thioether bridged structures) are reported (koehbach and craik, 2019) . the membrane-targeting mechanisms of amps can be described through models, including the pole and carpet models and the pole model can be further divided into the toroidal pore and barrel-stave models (figure 6 ). the toroidal pore model is also known as the wormhole model. in this model, amps vertically embedded in the cell membrane accumulate and then bend to form a ring hole with a diameter of 1-2 nm (matsuzaki et al., 1995 (matsuzaki et al., , 1996 . the typical examples of this model are magainin 2, lacticin q, and arenicin. furthermore, cationic peptides, including tc19, tc84, and bp2, compromise the membrane barrier by creating fluid domains (omardien et al., 2018) . antimicrobial peptides aggregate with each other, penetrate the bilayer of the cell membrane in the form of multimers, and form channels that result in the cytoplasmic outflow. in severe cases, amps can induce cell membrane collapse and lead to cell death (lohner and prossnigg, 2009 ). for instance, alamethicin performs its pore-forming activity by using this model. besides, hairpin amp protegrin-1 can form stable octameric β-barrels and tetrameric arcs (half barrels) in implicit and explicit membranes by simulations (lipkin and lazaridis, 2015) . antimicrobial peptides are arranged parallel to the cell membrane. their hydrophilic end faces the solution, and their hydrophobic end faces the phospholipid bilayer. amps will cover the membrane surface that similar to a carpet and destroy the cell membrane in a 'detergent'-like manner (oren and shai, 1998) . however, this pore-forming mechanism requires a certain concentration threshold and the required concentration of amps is high. human cathelicidin ll-37 exhibits its activity through this mechanism, and amps with β-sheet structure also play a role in this model (shenkarev et al., 2011; corrêa et al., 2019) . polarized light-attenuated total reflection fourier transform infrared spectroscopy (atr-ftir) was used to study the effect of amp cecropin p1 on the bacterial cell membrane and found that it was an applied flat on the surface of the pathogen's cell membrane to destabilize and eventually destroy the cell membrane . membrane targeting mechanisms (the cell membrane composition differences of bacteria and fungi shown in figure 7) can be further refined to address the large differences in the lipid composition of the cell membranes of bacteria, fungi, and mammals. the main lipids in cell membranes include glycerophospholipids (gpls), lysolipids, sphingolipids, and sterols. phosphatidylethanolamine (pe), phosphatidylglycerol (pg), and cardiolipin (cl) are the most common anionic lipids in bacteria, whereas phosphatidylcholine (pc), phosphatidylinositol (pi), pe, and phosphatidic acid (pa) are the main gpls in fungal cell membranes (ejsing et al., 2009; singh and prasad, 2011; li et al., 2017) . furthermore, fungal cell membranes are more anionic than mammalian cell membranes and have higher pc content. meanwhile, ergosterol is the sterol found in the plasma membrane of lower eukaryotes, such as fungi, whereas that of animals contains cholesterol (faruck et al., 2016) . many amps take advantage of differences in membrane components to exert their effects. antimicrobial peptides are promising to be anti-biofilm agents but it should be noticed that they are different from the cell penetrating peptides (cpps) which typically comprise 5-30 amino acids and can translocate across the cell membrane. cpps could be categorized according to physicochemical properties into three classes: cationic, amphipathic, and hydrophobic, but anti-biofilm peptides have stricter requirements for these physicochemical properties. anti-biofilm peptides target the biofilms by different mechanisms including (1) degradation of signals within biofilms; (2) permeabilize within cytoplasmic membrane/eps; (3) modulating eps production etc. and then can address chronic multi-resistant bacterial infections (pletzer et al., 2016; ribeiro et al., 2016; guidotti et al., 2017; derakhshankhah and jafari, 2018; rajput and kumar, 2018) . for instance, saap-148, synthesized based on ll-37, showed activity to prevent biofilm formation by s. aureus and a. baumannii (crunkhorn, 2018) . the way of amps entering cells is direct penetration or endocytosis. after entering the cytoplasm, amps will identify and act on the target. depending on the target, amps can be divided into the following categories. antimicrobial peptides affect transcription, translation, and assembly into functional peptides through molecular chaperone folding by interfering with related enzymes and effector molecules. for example, bac7 1-35 targets ribosomes to inhibit protein translation (mardirossian et al., 2014) , whereas tur1a inhibits protein synthesis in e. coli and thermus thermophilus by inhibiting the transition from the initial phase to the extension phase. however, the differences between tur1a and bac7 also lead to various ways of binding to ribosomes and interacting with the ribosomal peptide exit tunnel (mardirossian et al., 2018) . but some amps' have different targets. for instance, genome-wide transcription shows that the amp dm3 can affect many important intracellular pathways of protein biosynthesis . chaperones are key proteins for correctly folding and assembling newly synthesized proteins and make them have stereoisomerism, which makes amps have cell selectivity and can prevent cytotoxicity. according to a previous review: both pyrhocoricin and drosocin can prevent dnak from refolding misfolded proteins by inducing a permanent closure of the dnak peptide-binding cavity (kragol et al., 2001; le et al., 2017; wrońska and boguś, 2020) . antimicrobial peptides can affect key enzymes or induce the degradation of nucleic acid molecules to inhibit nucleic acid biosynthesis. indolicidin, a c-terminal-amidated cationic trprich amp with 13 amino acids, specifically targets the abasic site of dna to crosslink single-or double-stranded dna and it can also inhibit dna topoisomerase i (subbalakshmi and sitaram, 1998) . tfp (tissue factor pathway inhibitor)1-1tc24, which is an amp from tongues, enters the cytoplasm of target cells after the rupture of cell membrane and then degrades dna and rna (he et al., 2017) . many amps can inhibit various metabolic activities by inhibiting protease activity. for example, histatin 5 has a strong inhibitory effect on the proteases secreted by the host and bacteria. amps enap-2 and indolicidin inhibit microbial serine proteases, elastase, and chymotrypsin (le et al., 2017) . cathelicidin-bf is a peptide isolated from the venom of bungarus fasciatus, it can effectively inhibit thrombin-induced platelet aggregation and further block protease-activated receptor 4 (shu et al., 2019) . antimicrobial peptides inhibit cell division by inhibiting dna replication and dna damage response (sos response), blocking the cell cycle or causing the failure of chromosome separation (lutkenhaus, 1990) . for instance, app (glaraltrllrqltrqltra), which is an amp with 20 amino acid residues, can efficiently kill c. albicans because of its cell-penetrating efficiency, strong dna-binding affinity, and ability to induce s-phase arrest in intracellular environment . mciz, which has 40 amino acid residues, is an effective inhibitor of bacterial cell division, z-ring formation, and localization (cruz et al., 2020) . moreover, it has been reported that several afps have damaging effects on the organelles of fungi. for example, histintin 5 can interact with mitochondria, causing the production of ros, and inducing cell death (helmerhorst et al., 2001) . in addition to intracellular targets, differences in cell wall composition, such as lipopolysaccharide (lps), lipid a and mannoproteins, are potential targets for amps. specifically, gram-positive and gram-negative bacteria are classified based on their bacterial cell wall structure. gram-positive bacteria have a layer of cross-linked peptidoglycan, whereas gram-negative bacteria have an additional outer membrane with an inner leaflet containing only phosphatidic acid and an outer leaflet made of lps. lps has numerous negatively charged phosphate groups, which combine with a salt bridge with a divalent cation (e.g., ca 2+ and mg 2+ ) to form an electrostatic network (nikaido, 2003) . this electrostatic zone is the main barrier against hydrophobic antibiotics and causes the low permeability of gram-negative bacteria. the main components of the fungal cell wall are mannoprotein, β-glucans and chitin (polymers of 1,4-β-n-acetylglucosamine) and the mutations in the relevant genes of the lps pathway and phospholipid trafficking provide resistance to the amps (cabib, 2009; spohn et al., 2019) . mannoproteins in fungal cell walls include a variety of proteins, including structural proteins, cell adhesion proteins (floccrin and lectin) and enzymes involved in cell wall synthesis and remodeling (hydrolytic enzymes and transglycosylase). these proteins differ from human cell membrane proteins and are potential targets of afps (rautenbach et al., 2016) . furthermore, teichoic acid and lipoteichoic acid in the cell wall are also potential targets of amps and these theories could support the design of amps with low cytotoxicity. antimicrobial peptides have good application prospects. however, amps have the following problems. (1) amps damage the cell membrane of eukaryotes and cause hemolytic side effects; (2) rising production costs and technical problems limit their manufacture; (3) their stability is limited at certain ph; (4) amps have reduced activity under the presence of iron and certain serum; (5) amps are easily hydrolyzed by proteases. therefore, the ideal amp should meet the following characteristics: (i) high antimicrobial activity; (ii) low toxicity to mammalian membranes; (iii) high protease and environment stability; (iv) low serum binding capacity and (v) ease of access and low cost production . therefore, designing amps to achieve the desired effect has attracted increasing attention. the rational design of antibacterial peptides should focus on the following five aspects: chain length, secondary structure, net charge, hydrophobicity, and amphiphilicity and these have been mentioned in many studies and this review will focus more on several specific methods of antimicrobial peptide design. site-directed mutation refers to the redesign of natural antimicrobial peptides by adding, deleting or replacing one, or several amino acid residues (torres et al., 2019) . the de novo design of peptides attaches importance to the design of amphiphilic amps (guha et al., 2019) . for example, gala is a well-known de novo-designed amp. amphipathic α-helical peptide gala is created by placing protonatable glutamic acid residues in most positions with the spacing of i to i + 4 (goormaghtigh et al., 1991) . the repeated sequence (xxyy)n, where x 1 and x 2 are hydrophobic amino acids, y 1 and y 2 are cationic amino acids, and n is the number of repeat units, is designed based on the hydrophobicity cycle that mimics natural α-helical amps and successfully designs broadspectrum α-helical amps. sequences (lkkl) 3 and (wkkw) 2.5 have the highest selectivity (khara et al., 2017) . moreover, l l k m w 2 model peptides are also de novo-designed peptides. amphipathic helical properties were conferred by using leucines and lysines, and two tryptophan residues were positioned at the amphipathic interface between the hydrophilic ending side and the hydrophobic starting side. among the model peptides, l 4 k 5 w 2 has good anti-mrsa activity (lee et al., 2011) . sequence templates can be obtained by comparing a large number of structurally homologous fragments of natural amps (such as hdps) and extracting conservative patterns based on the type of residue (such as charged, polar, hydrophobic, etc.) (zelezetsky and tossi, 2006) . based on the modification, the parameters, such as helix formation tendency, cationic, amphiphilicity and overall hydrophobicity, can be systematically changed. for instance, cecropin, magainin, protegrin, and lactoferrin have all been used as amp templates (fjell et al., 2012) . peptides can form nanostructures, such as micelles, vesicles, nanotubes, nanoparticle nanobelt, and nanofibre nanotube, and can increase or impart antibacterial activity to amps during the self-assembly of peptides. for example, kld-12 (kld) is a self-assembling peptide with 12 amino acid residues that can adopt nanostructures and are known for their tissue engineering properties. the addition of arg residues in kld shows no remarkable change in its β-sheet secondary structure and the self-assembly characteristics of the forming nanostructures (tripathi et al., 2015) . dimer structure can also be used to enhance the antimicrobial activity of amps and reduce toxicity, but membrane-destabilizing effects are reduced after dimer formation (malekkhaiat häffner and malmsten, 2018). various chemical modifications of amps, including residue phosphorylation, the addition of d-amino acids or unnatural amino acids (homoarginine), cyclization, halogenation, acetylation, and peptidomimetics, have been used to improve the stability of peptides against proteases. given that the enzyme is stereospecific, the incorporation of unnatural d-amino acids into the amp sequence can reverse the stereochemistry and prevent protease degradation (zhong et al., 2020) . the so-called peptidomimetics, whose main elements mimic the structure of peptides, are usually produced by modifications, such as chain extension or heteroatom incorporation of existing peptides (patch and barron, 2002) . ornine, which is an unnatural residue with a positive charge and has a high resistance to protease activity, is also used in non-chemical modification. replacing trp residues with family residues, such as β-dihydrophenylalanine, can stabilize secondary structures and improve antibacterial properties (maurya et al., 2013) . halogenation is highly related to the activity, specificity, and stability of amps. in the latest report, halogen is introduced into jelleine-i which is a short peptide isolated from the royal jelly of honeybees (apis mellifera) by replacing phenylalanine with a halogenated phenylalanine analog, increasing the antibacterial activity in vitro and anti-biofilm activity. in addition, the proteolytic stability of jelleine-1 is increased by 10-100 times by halogenation (jia et al., 2019) . the halogenated peptidomimetic α,α-disubstituted β-amino amides are also promising bacteriostatic drugs that have inhibitory effects on more than 30 multi-resistant clinical isolates of gram-positive and gram-negative bacteria (paulsen et al., 2019) . halogenation is also related to the specificity of amps. the o-fluorine substitution in phenylalanine residues maintains the activity of temporin l on e. coli but leads to the loss of activity on s. aureus and p. aeruginosa (setty et al., 2017) . three modes of cyclisation, including cyclisation via disulfide bonds, head-to-tail cyclisation and internal bonding between side chains, have been found in natural amps. the synthesis of disulfide bonds often complicates the development of synthetic peptides. the circularisation of the main chain of arenicin-1 molecule resulted in increased activity against drug-resistant clinical isolates but caused no substantial effect on cytotoxicity (orlov et al., 2019) . the hdps tachyplesins i, ii, and iii and their cyclic analogs cti, ctii, and ctiii, respectively, have similar structures and activities and can resist bacterial and cancer cells. the cyclisation of the backbone reduces the hemolytic activity and improves the stability of the peptides whilst maintaining effective anticancer and antibacterial activities (vernen et al., 2019) . capping refers to the addition of specific motifs or modifications, such as amidation at the c-terminus and acetylation at the n-terminus, rendering amps with more natural peptide characteristics. post-translational modifications play an important role in the function of amps and are the most commonly used in peptide design. the c-terminal rana box (consisting of a c-terminal cyclic heptapeptide with a conservative disulfide bond) and amide group are important c-terminal capping methods. for example, the c-terminal amide group of maximin h5 can enhance antibacterial efficacy without increasing lytic ability (dennison et al., 2015) . the n-terminal lipidated analog c 4 vg 16 krkp shows enhanced antibacterial activity against various gram-negative bacteria. the functions of n-terminal lipidation include (i) increasing lps neutralization, (ii) increasing stability to proteases and peptidases, and (iii) reducing cytotoxicity (datta et al., 2016) . furthermore, hydrophobic end labeling is a commonly used method to increase the activity of antimicrobial peptides. acyl lipid peptides have a linear or cyclic structure in which one or more hydrocarbon tails are connected to the n-terminus of a short oligopeptide (chu-kung et al., 2010) . lipopeptides have covalently attached hydrophobic moieties, such as sterols or fatty acids. aromatic amino acid terminal labeling is also the main hydrophobic terminal labeling method. tryptophan (w) and phenylalanine (f) are the commonly used aromatic amino acids. their large and polarisable residues have an affinity for the interface, and the w/f tag is also sensitive to the differences between ergosterol and cholesterol and can prevent self-assembly. this condition results in low aggregation numbers and high critical aggregation concentrations (schmidtchen et al., 2014) . peptide conjugation has been the goal of most research in recent years to produce active and stable amps with high selectivity. different side chains or amp fragments can be used aside from the repetition of the same amino acid motifs. for example, conjugating fatty acids with a length of 8-12 carbon atoms to the 4th or 7th side chain of the d-amino acids of ano-d 4,7 improves antibacterial selectivity and anti-biofilm activity. in addition, the new peptide exhibits high stability against trypsin, serum, salt, and different ph environments (zhong et al., 2020) . the conjugation of different amps can also be performed. for example, the hybrid peptide (pa2-gnu7) constructed by the addition of pa2 to gnu7 has a high activity and specificity to p. aeruginosa . smamps include a broad family of molecular entities based on the structure and function of amps. however, their backbones are not entirely based on α-amino acids, including β-amino acid oligomers, arylamide oligomers, and phenylene ethynylenes (michael henderson and lee, 2013) . for instance, smamp10, which is a potential drug for intravenous treatment, causes no drug resistance and has a strong inhibitory effect on mrsa and vancomycin-resistant enterococcus faecium (tew et al., 2006) . peptoids are peptide isomers, in which the side chain is bonded to the main chain nitrogen instead of α-carbon or poly-nsubstituted glycine in which the side chain is connected to amide nitrogen instead of the α-carbon on the main chain (andreev et al., 2018) . for example, the cationic peptide sa4 (iowagolfolfo-nh2) and its poly-n-substituted glycine homolog spo (ninonwnangnonlnfnonlnfno-nh 2 ) inhibit the planktonic and biofilm formation of a. baumannii strains, which are susceptible to multi-drug resistance (sharma et al., 2019) . motifs with specific functions have been reported increasingly. these motifs can be repeated units for combining into new antimicrobial peptides, or specific amino acid combination units appearing at the end (such as capping) of or even in the peptide chain. this motif includes two tripeptide structures, including gly-gly-his or val-ile-his, which are added at the end of the peptide chain. atcun-containing amps in the presence of hydrogen peroxide and ascorbic acid combine with cu 2+ to induce the valence of copper ions between +2 and +3 oxidation states and form an atcun-cu (ii) complex, generating ros by fenton-like reactions. extracellular polymeric substances (eps) are important for biofilms and can enhance the resistance of cells to antibacterial agents (flemming, 2016) . atcun-amps have been used to degrade environmental dna, which is one of the major components of eps. several related practical applications have been reported. for example, the biological activity against carbapenem-resistant enterobacteriaceae is increased by adding this motif to the n-terminus of an alpha-helical amp (such as cm15). besides, the cu-atcun derivative of ov-3 containing a c-terminal ggc sequence showed high levels of membrane permeation and lipid peroxidation. the concept of catalytic metal drugs has attracted widespread attention although the concept is still in its infancy because of the role of metal ions (alexander et al., 2017; agbale et al., 2019) . rana box: rana box is a heptapeptide motif (cglxglc) from the nigrocin family. rana box consists of two cysteine residues that are separated by four or five other residues on the side and can form a cyclic disulfide bond. rana box peptide has shown structural analogies with polymyxin (colistin), and the primary structure of the rana box motif is important in determining bacteriostatic activity (kozić et al., 2015) . the deletion of the 'rana box' motif will cause the amp antibacterial effect to disappear, but replacing the natural 'rana box' sequence of amps with amidated phenylalanine can expand its efficacy against antibiotic-resistant microorganisms, including mrsa and p. aeruginosa, and reduce cytotoxicity. this phenomenon also shows that the effect of the motif on amps needs to be determined based on the specific situation and is not completely beneficial (bao et al., 2018) . the lps binding motif (g-wkrkrf-g) can produce a broad spectrum of antibacterial activity when introduced into the c-terminus of temporin-1 ta and temporin-1 tb (close isoforms of temporin) (mohanram and bhattacharjya, 2016) . antifungal peptides have a conserved gxc(x 3−9 ) c γ-core motif (residues 5-14, gkcykkdnic; d-isomer) at its n-terminus, which is a cation part of the ring. this conserved motif interferes with the integrity of the plasma membrane of the cell (yount and yeaman, 2004) . conserved γ-core motifs are directly involved in protein-membrane interactions and strongly contribute to membrane binding (utesch et al., 2018) . if replace d-phe1-pro2 sequence in peptide chain with d-phe-2-abz turn motif (2-abz is an abbreviation of 2-aminobenzoic acid d-amino acid) in amp tyrc a, and nuclear magnetic resonance shows that this change retains the β-hairpin structure. unlike the traditional β-turn motif, the d-phe-2-abz motif can be used as a tool for β-hairpin libraries. the hydrophobic peptide can be formed into the nucleated β-hairpin formation by adding the d-phe-2-abz motif. moreover, the inclusion of this part in two designed cationic amphiphilic peptides can produce broadspectrum antibacterial activity and low hemolysis rate (cameron et al., 2017; cameron et al., 2018) . the ngr motif is composed of asn-gly-arg, and amps with this structure have strong cytotoxicity ( table 1 ). the data indicate that the new amps containing ngr may bind to cd13+ or αvβ3+ tumor cells by binding to cd13 or αvβ3, respectively, to exert anti-tumor activity, especially on cd13+ tumor cells . the central gxxxg motif can induce strong self-assembly and have been already used in the design of amps (brosig and langosch, 1998; krauson et al., 2012) . bovine lactoferrin b is an amp composed of 25 amino acid residues and has antibacterial, antifungal, and antiparasitic activities. the multivalent molecules lfcinb (20-25) 2 and lfcinb (20-25) 4 contain the lfcinb (20-25) motif (rrwqwr) and show inhibition activity against e. coli, p. aeruginosa, and s. aureus. chimeric peptide chimera 3 containing two motifs, namely, the rrwqwr of lfcinb (20-25) and the rllr of bfii computer design includes simple statistical modeling, structureactivity relationships study (abdel monaim et al., 2018) , neural networks (müller et al., 2018) , deep learning (veltri et al., 2018) , word embedding (hamid and friedberg, 2018) and machine learning. for example, a machine learning method by matlab is proposed based on the concept of scoring the contribution of each amino acid's antibacterial activity (wu x. et al., 2014) . the genetic algorithm was used to design the amphiphilic α-helical peptide guavalin 2, which has an uncommon amino acid composition (three tyrosine and three glutamine residues) and interestingly causes membrane hyperpolarization, which is a different mechanism from those of other amps (porto et al., 2018) . two research methods have been developed based on the research background of quantitative structure-activity relationships: prediction method based on amp therapeutic index and the identification of novel potential amps from the expressed sequence tag database based on the principles of the highly conserved signal peptide subclasses related to amps (juretić et al., 2011) . in this way, a variety of amp variants can be obtained. if combined with high-throughput screening, it can effectively obtain the desired amp. for instance, some new amps are designed by the combinatorial peptide library of melittin and show higher activity and lower cytotoxicity (krauson et al., 2015) . cations, such as na + and mg 2+ , may affect amp activity . however, the different valences of metal ions have varied effects on amps. for example, divalent cations show stronger antagonism to bacteria than monovalent cations with thanatin and s-thanatin, which are insect amps (wu et al., 2008) . in the presence of nacl, the signal response during the association phase remarkably decreased in single-cycle and multi-cycle kinetic experiments, resulting in a decreased association rate. this occurrence may be caused by the shielding effect of nacl between the cationic peptide and the zwitterionic membrane. another possible reason is that na + can bind to the phospholipid bilayer, where the ions interact with the phosphate and the carbonyl oxygen of lipid head groups (sabapathy et al., 2020) . the reduced activity of synthetic peptide [rllr] 5 under high salt concentration is possibly caused by the destruction of its α-helix structure. table 2 shows that several amps, including histatin, myxinidin, and hepcidin, contain atcun motifs (amino terminal copper and nickel with xxh sequence). iron is the most abundant metal ion in human saliva, but the combination with this metal ion results in the loss of the α-helix of histatin 5 and greatly reduces its antifungal activity (puri et al., 2015) . however, the coordination of copper (ii) and nickel (ii) ions can induce the formation of ros, which is essential for bactericidal activity (jeżowska-bojczuk and stokowa-sołtys, 2018). anionic amps have a large number of negatively charged aspartic and glutamic acid residues (lakshmaiah narayana and chen, 2015) . they require zinc as a functional cofactor and the zinc complex shows stronger antibacterial activity (jiang et al., 2014) . several of these amps use metal ions to form cationic salt bridges with the negatively charged components of the microbial membrane to penetrate the membrane. anionic amps may attach to ribosomes or inhibit ribonuclease activity when in the cytoplasm (jeżowska-bojczuk and stokowa-sołtys, 2018). metal ions also affect the self-assembly of peptides. these ions can recognize specific amino acids, such as lysine and glutamic acid, and may form salt bridges between peptide molecules to induce peptide self-assembly. for example, zn 2+ can stabilize the aggregation of peptides on the cell membrane, which results in the enhanced antibacterial effect of dcd-1l in the presence of zn 2+ (tian et al., 2015) . ph many amps are stable and retain their antimicrobial activity in a wide ph range. amps have enhanced activity at low ph because of their basic properties. this condition is related to the protonation of histidine at acidic ph, which promotes electrostatic interactions with anionic surfaces, including lps and the anions of phospholipids, and subsequently enhances antibacterial properties. the effect of ph on the antibacterial activity of amps varies. for example, thanatin's activity at neutral ph is slightly higher than that under acidic conditions. by contrast, the activity of xylan on e. coli, listeria, and c. albicans is remarkably higher at ph 5.5 than at ph 7.4 (holdbrook et al., 2018) . the inactivation of the histidinecontaining amp c18g-his under low ph conditions involves ph-dependent changes in the state of the aggregates in the solution, because the aggregates, which are sensitive to ph and lipid composition, may be affected by binding and conformation. peptides can also enhance bacterial membrane permeability at low ph (hitchner et al., 2019) . thrombin-derived c-terminal peptides (tcps) will also change the mode of cd14 (a protein that is abundant in human plasma) from anti-inflammatory mode to bacterial elimination mode from ph 7.4 to ph 5.5 (holdbrook et al., 2018) . a dimer (e.g., p-113) can be created to provide amps with resistance to a higher ph range. the sensitivity of this ph-sensitive amp can be used to achieve a certain targeting effect in practical applications. in addition, charge interaction is one of the most important factors in peptide self-assembly. ph affects the charge state of amino acid and substituent functional groups. therefore, adjusting the ph is the most common method for controlling peptide assembly and disassembly (tian et al., 2015) . proteases have a strong destructive effect on amps. for instance, ll-37, which has the strongest inhibitory effect on chlamydial infection, is inhibited by the protease chlamydial protease-like activity factor (cpaf) secreted by chlamydia (tang et al., 2015) . studies have been focused on the design of amp carriers to solve this problem (lewies et al., 2017; nordström et al., 2019) . the presence of chitosan-silica solid support of kr-12 peptide can protect it be hydrolyzed by α-trypsin, and the degree of protection is increased by 38% compared with the free kr-12 (diosa et al., 2020) . however, several enzymes, such as protease 65, esterase 66 and phosphatase 67, cut the blocking group of the peptide and trigger the self-assembly of the peptide, which positively affects amps (tian et al., 2015) . antimicrobial peptides can regulate pro-inflammatory reactions, recruit cells, stimulate the proliferation of cells, promote wound healing, modify gene expression and kill cancer cells to participate in the immune regulation of human skin, respiratory infections, and inflammatory diseases (de la fuente-núñez et al., 2017) . for example, α-defensins hnp-1, hnp-2, and hnp-3 showed effective antibacterial activity against adenovirus, human papilloma virus, herpes virus, influenza virus and cytomegalovirus. pulmonary diseases, such as idiopathic pulmonary fibrosis, alveolar proteinosis, and acute respiratory distress syndrome, show elevated levels of amps (guaní-guerra et al., 2010) . likewise, amps secreted by the paneth cells in the mammalian gut are important to shape the gut microbiota (bevins and salzman, 2011) . the application of amps in medicine, such as dental, surgical infection, wound healing and ophthalmology is developing now. but there are only three amps that have been approved by fda including gramicidin, daptomycin, and colistin. dental caries, endodontic infections, candidiasis, and periodontal disease are common diseases in the human oral cavity. dental caries is a prevalent oral disease and some acidogenic bacteria like streptococcus sp. are the main cariesassociated pathogens (izadi et al., 2020) . several amps have good application potential. for instance, peptide zxr-2 (fkiggfikklwrslla) has shown potent activities against pathogenic bacteria of dental caries, streptococcus mutans, streptococcus sobrinus, and porphyromonas gingivalis and peptide pac-113 (clinical trial identifier: nct00659971) that has been sold over the counter in taiwan for treating oral candidiasis (chen l. et al., 2017) . in surgical infection and wound healing: surgical infection occurs after surgery, burns, accidental injury, skin disease, and chronic wound infections have a serious hazard to human life (thapa et al., 2020) . several amps have shown the therapeutic potential of these diseases. for example, amp pxl150 shows pronounced efficacy as an anti-infective agent in burn wounds in mice and amp d2a21 has been in the third phase of clinical trials for treating burn wound infections (björn et al., 2015) . in ophthalmology: human eyes are prone to be infected by several organisms including bacteria and fungi in which s. aureus, streptococcus pneumoniae, p. aeruginosa, aspergillus spp., and c. albicans are the most relevant pathogens (silva et al., 2013) . although amps such as lactoferricin b, protegrin-1 exhibited antimicrobial activity against these pathogenic bacteria, their application in the field of ophthalmology is only at the theoretical stage. with the popularity of contact lenses and the increase in cases of related eye infections, antimicrobial peptides have shown good application prospects in ophthalmology (khan and lee, 2020) . additional methods need to be performed for the application of amps as drugs in medicine. the main strategies include (1) constructing precursors to reduce cytotoxicity and improve protease stability, (2) using amps in combination with existing antibacterial agents, (3) inducing the correct expression of amps with appropriate drugs and using engineering probiotics as vectors to express amps. for example, in the field of wound repair, different formulation strategies, such as loading amps in nanoparticles, hydrogels, creams, gels, ointments, or glutinous rice paper capsules, have been developed to effectively deliver amps to the wound (borro et al., 2020; thapa et al., 2020) . in recent research, the sponges developed from modified starch and hs-peg-sh are covalently immobilized with amp showed effective antibacterial activity (yang et al., 2019) . more technical means, including pheromone-labeled amps, local environment-triggered amps (enzyme precursor drug release system, ph-activated amps, etc.), have been developed to improve the targeting mechanism of amps. furthermore, nanotubes, quantum dots, graphene, and metal nanoparticles have been proposed to be a potential method to enhance drug delivery of amps (magana et al., 2020) . hybrid peptides have also been used to build targeting peptides. for example, pa2, which is a p. aeruginosa-targeting peptide, was combined with gnu7 (a broad-spectrum amp) to construct a hybrid peptide (pa2-gnu7) that targets oprf protein and has good bactericidal activity and specificity . furthermore, some antibiotics, for instance, daptomycin (a lipopeptide), lugdunin which is a 21-membered cyclic peptide consists of 6 amino acid residues plus a thiazolidine moiety and telavancin (a glycopeptide) have been widely used for the clinic (durand et al., 2019; lampejo, 2020) . although they are antibiotics, they have provided broader ideas for the design of amps. food preservatives have potential harm to the human body. therefore, natural preservatives are being advocated by more people. amps have a good inhibitory effect on common bacteria and fungi in food, and many amps are resistant to acids, alkalis, and high temperatures are easily hydrolyzed by proteases in the human body. thus, amps are a promising alternative to preservatives. nisin is a bacteriocin produced by l. lactis subspecies. lactic acid bacteria have been widely used as food preservatives. nisin is categorized as generally recognized as safe (gras) by the us food and drug administration (fda) and is used as a food preservative in other countries (khan and oh, 2016) . however, only nisin and polylysine are currently approved by the fda as food additives (santos et al., 2018) . pedocin pa-1, a bacteriocin consisting of 44 amino acids produced by a diplococcus, is also used as a food preservative and is sold on the market under the trade name alta 2431. pedocin pa-1 is used as a food additive to inhibit the growth of l. monocytogenes, which can cause meat deterioration (settanni and corsetti, 2008) . enterocin as-48 is an amp used to preserve cider, fruit and vegetable juices, and enterocin ccm4231 is used to preserve soy milk (rai et al., 2016; santos et al., 2018) . encapsulating bacteriocins into liposomes is a new method used to overcome the problems of amps in food applications (such as proteolytic degradation or interaction with food ingredients) (da silva malheiros et al., 2010) . moreover, active packaging by adding amps is a novel packaging method that has great potential in the food industry. for instance, ε-poly-l-lysine is used in conjunction with starch biofilms to show good inhibitory effects on aspergillus parasiticus (aflatoxin producer) and penicillium expansum and nisin have the potential to be dairy preservative because it is a highly surface-active molecule (luz et al., 2018) . the european union banned the use of animal growth promoters in animal feed in 2006. thus, a new antibacterial strategy is needed. many amps are the potential to be used in poultry, swine, and ruminants breeding and aquaculture because they can improve production performance (liu et al., 2008; bao et al., 2009) , immunity and promote intestinal health and some of them have a stronger inhibitory effect on bacterial inflammation if used with antibiotics cote et al., 2020) . for example, siamp has a good effect on the treatment of ibv in chicken (sun et al., 2010) . by adding swine gut intestinal antimicrobial peptides (sgamp), broilers showed higher average daily gain and feed efficiency under chronic heat stress conditions (hu et al., 2017) . frog caerin 1.1, european sea bass dicentracin and nk-lysine peptides (nklps) have good inhibitory effects on nodavirus, septicaemia haemorrhagic virus, infectious pancreatic necrosis virus and spring viremia carp virus, which are devastating to fish farming (león et al., 2020) . the amp in soybean meal fermented by b. subtilis e20 effectively inhibits v. parahaemolyticus and vibrio alginolyticus and enhances the resistance level of litopenaeus vannamei against v. parahaemolyticus when added to feeds (cheng et al., 2017) . for agriculture, the plant pathogenic infection of bacteria and fungi causes the loss of economy, for instance, aspergillus flavus infection of corn and peanuts, citrus green mold caused by penicillium digitatum, gray mold disease caused by botrytis cinerea on strawberries and geotrichum citriaurantii infection of citrus fruit all cause great harm to the growth and post-harvest of agricultural products (liu et al., 2007; liu et al., 2019) . several afps have shown prospect to control these problems. however, the practical application of antimicrobial peptides in the transportation and preservation of agricultural products is still lacking, because the use of antimicrobial peptides will greatly increase the cost in the transportation of fruits and vegetables (application examples of amps in these four fields are shown in table 3 ). antimicrobial peptides constitute a global research hotspot, but many key issues in design and application need to be solved urgently. several restrictive factors hinder the application of amps. the interaction of multidisciplinary subjects, such as biology, materials science, chemistry, bioinformatics, molecular informatics and pharmacy can further develop prospective amps. computer molecular dynamics simulation, cell membrane simulation, and more methods are being applied to study the mechanism of amps. how to further understand the correlation between amps and various targets instead of conducting one-sided experimental research might improve experimental designs to obtain stronger systemic and scientific demonstrations. on this basis, further animal experiments are required instead of simple cell-level experiments to test the effect of amps under complex physiological conditions. several complicated methods, such as the chemical method of peptidomimetics and non-natural amino acid modifications, have been applied in designing amps to solve the problem of protease hydrolysis. most methods use chemical substrates, but the cost of these methods cannot be ignored in practice. in addition, chemical synthesis and the use of engineered bacteria are currently the mainstream for such procedures. finding a better biological preparation method, reducing the cost and increasing the yield is important problems in practical application. furthermore, studying the amp expression of the organism itself and finding a better expression vector are necessary for mass production in the future as more amps in nature are discovered. further research is needed on the reported amps to solve the problem on structure-function relationship. as a branch of peptide drugs, amps need to progress with the advancement of medical science against the background of the current low success rate of 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an antimicrobial peptide, magainin 2, induced rapid flip-flop of phospholipids coupled with pore formation and peptide translocation role of the escherichia coli sbma in the antimicrobial activity of proline-rich peptides mechanism of action of novel synthetic dodecapeptides against candida albicans anti-inflammatory effects of egg yolk livetins (α, β, and γ-livetin) fraction and its enzymatic hydrolysates in lipopolysaccharideinduced raw 264.7 macrophages promising antimicrobial agents designed from natural peptide templates lollipop'-shaped helical structure of a hybrid antimicrobial peptide of temporin b-lipopolysaccharide binding motif and mapping cationic residues in antibacterial activity antifungal activity determination for the peptides generated by lactobacillus plantarum te10 against aspergillus flavus in maize seeds recurrent neural network model for constructive peptide design current treatment options and the role of peptides as potential therapeutic components for middle east respiratory syndrome (mers): a review epinecidin-1, a highly potent marine antimicrobial peptide with anticancer and immunomodulatory activities molecular basis of bacterial outer membrane permeability revisited. microbiol degradable dendritic nanogels as carriers for antimicrobial peptides myticusin-beta, antimicrobial peptide from the marine bivalve bactericidal activity of amphipathic cationic antimicrobial peptides involves altering the membrane fluidity when interacting with the phospholipid bilayer mode of action of linear amphipathic α-helical antimicrobial peptides ponericins, new antibacterial and insecticidal peptides from the venom of the ant pachycondyla goeldii redesigning arenicin-1, an antimicrobial peptide from the marine polychaeta arenicola marina, by strand rearrangement or branching, substitution of specific residues, and backbone linearization or cyclization expression systems for heterologous production of antimicrobial peptides lipidation increases antiviral activities of coronavirus fusion-inhibiting peptides mimicry of bioactive peptides via nonnatural, sequence-specific peptidomimetic oligomers antimicrobial activity of amphipathic α,α-disubstituted β-amino amide derivatives against esbl -carba producing multi-resistant bacteria; effect of halogenation, lipophilicity and cationic character use of click chemistry for obtaining an antimicrobial chimeric peptide containing the lfcinb and buforin ii minimal antimicrobial motifs anti-biofilm peptides as a new weapon in antimicrobial warfare in silico optimization of a guava antimicrobial peptide enables combinatorial exploration for peptide design iron binding modulates candidacidal properties of salivary histatin 5 antimicrobial peptides as natural bio-preservative to enhance the shelf-life of food anti-biofilm peptides: a new class of quorum quenchers and their prospective therapeutic applications antifungal peptides: to be or not to be membrane active antimicrobial peptides: premises and promises targeting leishmania major parasite with peptides derived from a combinatorial phage display library new frontiers for anti-biofilm drug development cyanobacterial peptides as a tour de force in the chemical space of antiparasitic agents the role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines revisiting the interaction of melittin with phospholipid bilayers: the effects of concentration and ionic strength nisin and other antimicrobial peptides: production, mechanisms of action, and application in active food packaging dermcidin: a novel human antibiotic peptide secreted by sweat glands effect of hydrophobic modifications in antimicrobial peptides the proline-rich antimicrobial peptide onc112 inhibits translation by blocking and destabilizing the initiation complex primary structures of six antimicrobial peptides of rabbit peritoneal neutrophils recent updates of marine antimicrobial peptides application of bacteriocins in vegetable food biopreservation modulating the antimicrobial activity of temporin l through introduction of fluorinated phenylalanine nkl-24: a novel antimicrobial peptide derived from zebrafish nk-lysin that inhibits bacterial growth and enhances resistance against vibrio parahaemolyticus infection in yesso scallop cationic antimicrobial peptide and its poly-n-substituted glycine congener: antibacterial and antibiofilm potential against a. baumannii the unique antimicrobial peptide repertoire of stick insects molecular mechanism of action of β-hairpin antimicrobial peptide arenicin: oligomeric structure in dodecylphosphocholine micelles and pore formation in planar lipid bilayers antimicrobial peptide cathelicidin-bf inhibits platelet aggregation by blocking protease-activated receptor 4. intern anti-yeast activity and characterisation of synthetic radish peptides rs-afp1 and rs-afp2 against food spoilage yeast dairy-derived antimicrobial peptides: action mechanisms, pharmaceutical uses and production proposals the importance of antimicrobial peptides and their potential for therapeutic use in ophthalmology comparative lipidomics of azole sensitive and resistant clinical isolates of candida albicans reveals unexpected diversity in molecular lipid imprints a molecular docking study revealed that synthetic peptides induced conformational changes in the structure of sars-cov-2 spike glycoprotein, disrupting the interaction with human ace2 receptor integrated evolutionary analysis reveals antimicrobial peptides with limited resistance antimicrobial activity of short arginine-and tryptophan-rich peptides mechanism of antimicrobial action of indolicidin swine intestine antimicrobial peptides inhibit infectious bronchitis virus infectivity in chick embryos chlamydiasecreted protease cpaf degrades host antimicrobial peptides antimicrobial peptides from different plant sources: isolation, characterisation, and purification antimicrobial activity of an abiotic host defense peptide mimic topical antimicrobial peptide formulations for wound healing: current developments and future prospects role of peptide selfassembly in antimicrobial peptides peptide design principles for antimicrobial applications variants of self-assembling peptide, kld-12 that show both rapid fracture healing and antimicrobial properties a computational modeling approach predicts interaction of the antifungal protein afp from aspergillus giganteus with fungal membranes via its γ-core motif synergistic bactericide and antibiotic effects of dimeric, tetrameric, or palindromic peptides containing the rwqwr motif against gram-positive and gram-negative strains deep learning improves antimicrobial peptide recognition characterization of tachyplesin peptides and their cyclized analogues to improve antimicrobial and anticancer properties antiviral peptides as promising therapeutic drugs evolutionary plasticity of insect immunity ionpair-π interactions favor cell penetration of arginine/tryptophanrich cell-penetrating peptides human antimicrobial peptides and proteins high specific selectivity and membrane-active mechanism of the synthetic centrosymmetric α-helical peptides with gly-gly pairs antimicrobial peptides: promising alternatives in the post feeding antibiotic era control of green and blue mold and sour rot in citrus fruits by the cationic antimicrobial peptide paf56 rhesus theta-defensin prevents death in a mouse model of severe acute respiratory syndrome coronavirus pulmonary disease heat shock proteins (hsp 90, 70, 60, and 27) in galleria mellonella (lepidoptera) hemolymph are affected by infection with conidiobolus coronatus (entomophthorales) peptide-based cancer therapy: opportunity and challenge effects of cations and ph on antimicrobial activity of thanatin and s-thanatin against escherichia coli atcc25922 and b. subtilis atcc 21332 in vitro and in vivo activities of antimicrobial peptides developed using an amino acidbased activity prediction method inhibition of sars-cov-2 (previously 2019-ncov) infection by a highly potent pancoronavirus fusion inhibitor targeting its spike protein that harbors a high capacity to mediate membrane fusion fabricating antimicrobial peptide-immobilized starch sponges for hemorrhage control and antibacterial treatment multidimensional signatures in antimicrobial peptides secretory production of antimicrobial peptides in escherichia coli using the catalytic domain of a cellulase as fusion partner comparative study of different forms of jellein antimicrobial peptide on leishmania parasite identification and biochemical characterization of a new antibacterial and antifungal peptide derived from the insect sphodromantis viridis alpha-helical antimicrobial peptides-using a sequence template to guide structure-activity relationship studies antimicrobial activity and mechanism of the human milk-sourced peptide casein201 an antimicrobial peptide containing ngr motif has potent antitumor activity against cd13+ and cd13-tumor cells antimicrobial peptides conjugated with fatty acids on the side chain of d-amino acid promises antimicrobial potency against multidrug-resistant bacteria isolation and structure of corticostatin peptides from rabbit fetal and adult lung characterization of antimicrobial activity and mechanisms of low amphipathic peptides with different α-helical propensity we thank the national key r&d program of china (2019yfd0901705). key: cord-270892-ycc3csyh authors: rollinger, judith m.; schmidtke, michaela title: the human rhinovirus: human‐pathological impact, mechanisms of antirhinoviral agents, and strategies for their discovery date: 2010-12-13 journal: med res rev doi: 10.1002/med.20176 sha: doc_id: 270892 cord_uid: ycc3csyh as the major etiological agent of the common cold, human rhinoviruses (hrv) cause millions of lost working and school days annually. moreover, clinical studies proved an association between harmless upper respiratory tract infections and more severe diseases e.g. sinusitis, asthma, and chronic obstructive pulmonary disease. both the medicinal and socio‐economic impact of hrv infections and the lack of antiviral drugs substantiate the need for intensive antiviral research. a common structural feature of the approximately 100 hrv serotypes is the icosahedrally shaped capsid formed by 60 identical copies of viral capsid proteins vp1‐4. the capsid protects the single‐stranded, positive sense rna genome of about 7,400 bases in length. both structural as well as nonstructural proteins produced during the viral life cycle have been identified as potential targets for blocking viral replication at the step of attachment, entry, uncoating, rna and protein synthesis by synthetic or natural compounds. moreover, interferon and phytoceuticals were shown to protect host cells. most of the known inhibitors of hrv replication were discovered as a result of empirical or semi‐empirical screening in cell culture. structure–activity relationship studies are used for hit optimization and lead structure discovery. the increasing structural insight and molecular understanding of viral proteins on the one hand and the advent of innovative computer‐assisted technologies on the other hand have facilitated a rationalized access for the discovery of small chemical entities with antirhinoviral (anti‐hrv) activity. this review will (i) summarize existing structural knowledge about hrv, (ii) focus on mechanisms of anti‐hrv agents from synthetic and natural origin, and (iii) demonstrate strategies for efficient lead structure discovery. © 2009 wiley periodicals, inc. med res rev, 31, no. 1, 42–92, 2010 human rhinoviruses (hrv) are the major cause of upper respiratory tract symptoms, the socalled common colds in humans. their name reflects the primary site of infection. because hrv are nonenveloped, icosahedral viruses of small size with a diameter of about 30 nm ( pico 5 small in latin) that consist of an rna genome, they were assigned to the family picornaviridae. currently, this virus family of the order picornavirales comprises the eight genera enterovirus, hepatovirus, cardiovirus, kobuvirus, teschovirus, erbovirus, aphthovirus, and parechovirus with 22 species and a multitude of serotypes. 1 because of high similarity in genome sequence and genome organization (fig. 1) , the former genera rhinovirus and enterovirus have been combined recently, keeping the existing name enterovirus (www.picornastudygroup. com/taxa/species/species.htm). an overview on the current taxonomy of picornaviruses pathogenic for humans as well as on newly proposed species of hrv is given in table i . at present the genus enterovirus includes four approved human enterovirus (hev) species (hev-a, -b, -c, and -d) and two approved hrv species (hrv-a and -b) (www. picornastudygroup.com/taxa/species/-species.htm). since 2007, the global distribution of highly divergent hrv strains was reported. [2] [3] [4] [5] based on the results of sequence, genomic, and phylogenetic analyses, it was proposed that these strains represent a new hrv species, hrv-c. [2] [3] [4] 6 in 2009, a further proposal concerning a new potential hrv-d species was published after sequencing and analysis of all known hrv genomes. 7 the approved and newly proposed species of the genus enterovirus share z70% homology (average amino acid identity) in the precapsid protein p1 as well as in 2c and 3cd. 3, [7] [8] [9] [10] different antigenic properties provide the basis for a further division of species into serotypes (table i) . about 100 rhinovirus serotypes are currently known. according to the currently approved taxonomy, most of them (75 and hrv hanks) belong to hrv-a and 25 of them to hrv-b. 11, 12 the genome of all known hrv-a and -b serotypes as well as of several field isolates of hrv-a, -b, and -c has been sequenced completely. 3, 7, [13] [14] [15] [16] [17] [18] [19] [20] viruses classified as hrv-c could not be grown in cell culture until now. phylogenetic analyses have been performed with partial sequences, 12, 21 as well as with the whole genome. 3, 7 the most recent and comprehensive analysis of all known hrv genomes revealed that (i) hrv-a and hrv-c share a common ancestor, which is a sister group to hrv-b, (ii) hrv-c represents a third species, and (iii) a basal divergence within hrv-a of three distinct strains that led to the proposal of a fourth species hrv-d. hrv-a and -b most often induce a mild, usually self-limited upper respiratory illness in humans characterized by nasal stuffiness and discharge, sneezing, sore throat, and cough. the conventional term is common cold. the common cold is a heterogeneous group of diseases caused by numerous viruses that belong to several different families e.g. rhinoviruses, coronaviruses, enteroviruses, and adenoviruses. 22 but, hrv represent the most common etiological agent worldwide. a large number of distinct strains circulate each year. 23 moreover, in a family or even in a single specimen, multiple hrv serotypes were detected simultaneously. [24] [25] [26] by using rt-pcr and culture, it was shown that hrv induce 22-50% of upper respiratory tract infections in adults as well as children. [27] [28] [29] [30] [31] higher incidence has been described from september to november, [32] [33] [34] and from april to may. 33, 34 in some years and perhaps some geographical areas, spring was a more important time for rhinovirus transmission. 33, 34 although overall rates of respiratory illness are lower in summer, rhinoviruses are the most frequently isolated at this time of year. 34 the incidence is inversely proportional to age. 25, 35 by age 2 years, 91% of the children have antibodies against rhinoviruses. 36 in addition to common cold, hrv are also involved in acute otitis media in children. 36, 37 moreover, data supporting a causative association with more severe lower respiratory tract infections of infants, elderly persons, and immunocompromised patients have been accumulated. [38] [39] [40] [41] [42] [43] [44] [45] studies of childhood and adult asthma have shown that hrv infections can also trigger exacerbations in patients with asthma, [46] [47] [48] [49] chronic obstructive pulmonary disease, [50] [51] [52] [53] [54] [55] and cystic fibrosis. [56] [57] [58] the recently discovered novel rhinovirus genotype hrv-c was associated with community outbreaks of influenza-like, acute upper respiratory infections and severe low respiratory tract infections of infants e.g. febrile wheeze, bronchiolytis, and asthma exacerbations, which peaked in fall and winter. [2] [3] [4] [5] [6] 26, 59, 60 in addition, the presence of hrv-c in the middle ear in patients with acute otitis media was demonstrated. 37 hrv spread occurs by means of virus-contaminated respiratory secretions that contain a high virus concentration. [61] [62] [63] besides direct hand-to-hand transmission, small-and largeparticle aerosol transmission of rhinoviruses has been shown. 61, 64, 65 children are important ''vectors'' for hrv transmission to family members. 25 moreover, studies with natural hrv-infected adults provided evidence that daily activities of infected people can lead to contamination of environmental surfaces with hrv e.g. light switches, telephone dial buttons and handsets, and virus transfer to fingers of healthy individuals for infection. 63, 66 because viral contamination of the hands plays an important role in transmission of hrv from person-to-person, interruption of this step of virus transmission presents a potential target for intervention. this was experimentally proved by treatment of hands by iodine 67, 68 or salicylic and pyroglutamic acid. 69 observations from experimentally induced infections in normal adult volunteers helped to understand the pathogenesis of hrv infections. [70] [71] [72] [73] [74] [75] the 50% human infectious dose of rhinovirus is low and the infection rate between 70 and 80%. after the deposition of hrv on nasal or conjunctival mucosa, viruses are transported to the posterior nasopharynx by mucociliary action of epithelial cells. specific receptors on epithelial cells in the adenoid area are used for binding and entry. already 8-10 hr after intranasal inoculation, infectious virus can be detected. 76 virus shedding peaks on the second day after infection and decreases rapidly thereafter. 75 but, small amounts of viruses were discovered in nasal secretions for up to 3 weeks after infection. virus and/or viral rna were demonstrated in the upper 70 as well as lower respiratory tract. 45, 72, 77, 78 using in situ hybridization, arruda et al. (1995) detected viral rna in a low number of ciliated cells in nasal biopsies. in the nasopharynx, a small portion of virus-positive ciliated as well as nonciliated cells was positive for viral rna. in 2000 papadopoulos et al. provided evidence that hrv may also lytically infect human bronchial epithelial cells in cell culture as well as in experimentally infected volunteers and induce the production of interleukin-6, -8, and -16. in agreement with these results, hrv rna was detected in 24-45% of children and 10-18% of adults with pneumonia. [79] [80] [81] [82] taken together, the results of natural cold studies as well as of experimental infection in human volunteers clearly demonstrate that hrv are able to replicate in the upper as well as in the lower airways. hrv infection triggers vasodilation and increased vascular permeability in the nasal mucosa, leading to nasal obstruction and rhinorrhoea. the mechanism is still incompletely understood because no histopathological changes were observed in nasal biopsy specimens from infected persons. 75 this led to the suggestion that clinical symptoms are primarily caused by the inflammatory response of the host to the virus infection and not by the cytopathic effect (cpe) of hrv. results of immunological investigations suggest a modest correlation between the concentrations of il-6 and il-8 in nasal secretions and the severity of symptoms in upper and lower hrv-induced respiratory tract disease. 78, 83 on day 2-4 after virus challenge, il-6 and il-8 concentrations were significantly greater in nasal secretions from experimentally infected symptomatic subjects than in those from infected asymptomatic or sham-challenged subjects. il-8 has been proposed as a mediator of neutrophile infiltrations that are observed during symptomatic infections. in experimental rhinovirus infection the onset of symptoms e.g. nasal stuffiness and discharge, sneezing, and cough was observed 10-12 hr after intranasal inoculation of the virus. 76 in contrast to rhinovirus infections in adults, fever is found in 15% of children with upper respiratory tract infections. 84 other symptoms in children and adults may be hoarseness, headache, malaise, and lethargy. sometimes viral infection is accompanied by bacterial complication, leading for instance to acute otitis media in about 20% of infected children, sinusitis, and pneumonia. [79] [80] [81] 85, 86 experimental infection was also used to study the causation between rhinovirus infection and asthma as well as copd exacerbations. 78, [87] [88] [89] [90] [91] [92] [93] it was shown that hrv infection enhances airway reactivity and predisposes allergic patients to develop late asthmatic reactions. 88, 91 rhinoviral colds were associated with an increase in histamine responsiveness that was accompanied by a bronchial mucosal lymphocytic and eosinophilic infiltrate. 89 in a recent study, an increased hrv-induced clinical illness severity in asthmatic compared with normal subjects was demonstrated. 93 strong relationships were shown between virus load, lower airway virus-induced inflammation, and asthma exacerbation severity. the results of this study also indicated that augmented th2 or impaired th1 or il-10 immunity are likely important mechanisms. mallia et al. provided evidence that low dose experimental rhinovirus infection in patients with copd induces symptoms and lung function changes typical of an acute exacerbation of copd. 92 viral replication and increased pro-inflammatory cytokine response were associated with symptomatic colds, increases in lower respiratory tract symptoms and reductions in forced expiratory volume in 1s or peak expiratory flow rate. the epidemiological data and pathology of hrv infections explain their high medical and socio-economic impact. millions of children and adults are taken ill with common cold every year, need medical consultations, are unable to attend school and go to work. 94, 95 direct costs include hospitalization, medical fees, and symptomatic treatment. moreover, exacerbations are the major cause of asthma and copd morbidity, mortality, and health care costs associated with these diseases. 92, 93 to date, specific drugs that prevent or reduce rhinovirus infection are not available. common cold can be treated only symptomatically with analgesics, decongestants, antihistamines, or antitussives and antibiotics are often wrongly prescribed. 96, 97 because of the large number of circulating hrv serotypes, treatment with specific antiviral drugs is considered to be more striking than vaccination. therefore, the search for new highly active synthetic and/or natural anti-hrv compounds is absolutely essential and represents an important area of antiviral research. such an anti-hrv drug would have to be (i) with broad spectrum activity because of the high number of hrv serotypes, (ii) administered very early in infection to demonstrate a good antiviral effect because of the fast infection kinetics, (iii) very safe because of the broad application by millions of people, and (iv) directed against a highly conserved target with low risk of resistance development. due to the very high error rates and the lack of proofreading ability in rna polymerases of picornaviruses, 98 naturally drug-resistant variants may exist in virus populations or resistant viruses can emerge under treatment. as with hiv, another highly variable rna virus, the risk of resistance development and/or selection of resistant virus variants could be minimized by applying combination of drugs directed against different targets. because clinical symptoms are suggested to be primarily caused by the inflammatory response of the host to the virus infection mediated by specific cytokines, a further advantage of drug combinations could be an additional immune-suppressive activity. the knowledge of structural components, nonstructural proteins that are necessary for viral multiplication, and stages of the viral life cycle is an essential precondition for the development of measures to prevent and treat hrv infection. the structure of hrv particles is well known. infectious virions consist of an icosahedral protein shell (capsid) that surrounds and protects the genome, a single positive-stranded rna molecule of approximately 7,400 nucleotides. the organization of the enterovirus genome is shown in figure 1 . the viral genomic rna is infectious and encodes a single, long, open reading frame flanked by untranslated regions (utr) at the 5 0 and 3 0 end. a small viral protein (vpg) is covalently linked to the 5 0 end. the 3 0 end is polyadenylated like cellular messenger rnas. structural components within these utrs e.g. the cloverleaf and the internal ribosome entry site (ires) of the 5 0 utr play an important role in rna replication as well as protein synthesis. 98 the nucleotide sequence of some regions within these structures is highly conserved among enteroviruses. their blockade could significantly inhibit viral replication. the molecular structure of hrv-1a, hrv-2, hrv-3, hrv-14, and hrv-16 was determined by x-ray crystallography. [99] [100] [101] [102] [103] [104] [105] the results show that the viral capsid is composed of 60 protomers of each of the three outer structural proteins vp1, vp2, and vp3 and of vp4 in the interior. a star-shaped plateau at the fivefold axis of symmetry, surrounded by a deep depression (canyon) and another smaller depression at the threefold axis were detected. moreover, a hydrophobic pocket was found beneath the canyon floor. with exception of hrv-14 and hrv-3, this pocket is occupied by a fatty acid, the so-called pocket factor. these host cell molecules have been suggested to play an important role in the viral life cycle by providing transient stability to the capsid during its movement from one host cell to another. 102 the outer surface of virions contains neutralization antigenic as well as host cell binding sites. the latter allow the virus to attach to molecules of the host cell membrane (adsorption), the receptors, and to start their life cycle. [106] [107] [108] based on their receptor use, two groups of hrv can be distinguished. the majority of hrv serotypes, the major group uses intercellular adhesion molecule-1 (icam-1) as their receptor. 109 the 12 viruses belonging to the minor group attach to low density lipoprotein (ldl) receptor, very-ldl (vldl) receptor, and ldlr-related protein on the cells whereat multiple receptors are involved. [110] [111] [112] hrv of the major group apply the canyon as attachment site for binding to icam-1. 113 in contrast, ldl receptors of minor group viruses bind near the tip of the five-fold vertex. 114 hrv-87 has been shown to utilize a sialylated glycoprotein as a cellular receptor. 115 furthermore, a hrv-89 variant as well as wild-type hrv-54 can use heparan sulphate proteoglycans for cell attachment in addition to icam-1. 116, 117 the interaction of rhinoviruses with their receptors leads to virus concentration on the cell surface. it induces the release of the pocket factor and conformational changes in the capsid and mediates viral entry via endocytosis. [118] [119] [120] [121] whereas icam-1 binding directly causes uncoating, 122, 123 release of the rna genome from the capsid of ldl-bound minor group rhinoviruses is triggered by acidification of the endosomal, ph-dependent pathway. [124] [125] [126] this detailed knowledge of the capsid structure and function as well as of the virus-receptor interaction offers a good possibility to develop antiviral drugs that interfere with the first steps of the viral life cycle, adsorption as well as uncoating. after uncoating, rhinovirus proteins are synthesized by the translation of a single, open reading frame using cellular ribosomes. the resulting polyprotein of approximately 250 kd is cleaved by viral proteases 2a pro and 3c pro into 11 final products (4 structural and 7 nonstrutural proteins) immediately after translation. 127, 128 at first, both proteinases release themselves from the polyprotein by selfcleavage. the primary cleavage of the viral polyprotein between p1 and p2 is mediated by 2a pro . thereafter, 3cd pro is released from the p3 precursor by autocatalytic cleavage. next, 3c pro and its precursor 3cd pro process proteins of the p1 (capsid proteins), p2, and p3 (nonstructural proteins) region. interestingly, 2a pro cleaves also the eif4gi/ii component of the translation initiation factor eif4f necessary for host cell protein synthesis, [129] [130] [131] and 3c pro and/or 3cd pro the rna polymerase transcription factors tfiid, tfiic, sl-1, and ubf. 98 therefore, effective inhibition of 2a pro and 3c pro would not only inhibit virus replication but could also prevent the shutoff of cellular protein and rna synthesis. moreover, the active site of proteinases is highly conserved among enterovirus serotypes. 132 this high conservation in conjunction with their important role in virus multiplication predestines these enzymes as targets for antiviral therapy. the viral rna polymerase 3d (3d pol ) represents another very important nonstructural protein of hrv. it forms a complex with both cellular and viral proteins, the rna replication complex. 98 this enzyme synthesizes viral minus-strand rna and uses it as template strand for the synthesis of genomic viral rna. vpg (3b) is the primer for negative-as well positive-strand rna synthesis. negative-strand, but not positive-strand rna synthesis, is stimulated by 2a pro . further viral accessory proteins include 2b, 2c, 2bc, and 3ab. besides 3d pol these proteins can play an important role in inhibition of viral rna synthesis by antiviral compounds. in summary, the knowledge of the structure of the viral capsid, proteases, and polymerase and their important function in the viral life cycle predestine these proteins as potential anti-hrv targets. hrv grow in several human and some primate cells expressing the minor group ldl receptors and/or the major group receptor icam-1. human cells susceptible to hrv infections include embryonic kidney, amnion, diploid fibroblasts from embryonic lung, tonsil, liver, intestine, and skin, adult fibroblast lines from aorta and gingival and the kb, hep-2, and hela continuous cell lines. 133 but, the susceptibility of hela cells and human fibroblasts to virus infection may vary. 32 hrv multiplication also occurs in primary human airway fibroblasts 134 and differentiated bronchial epithelium. 77, 78, 135 the proportion of infectible epithelial cells was shown to be between 3 and 10%. 77, 135 but, enhanced levels of viral production were detected in poorly differentiated in comparison to differentiated epithelial cells. 136 the degree of viral infection correlated with il-6 and il-8 induction in these cells virus growth causes a typical cpe characterized by ballooning, refractiveness, granularity, and shrinkage of infected cells. the hrv-induced cpe, infectious virus titers, viral protein expression, and rna synthesis can be chosen as parameters to evaluate the anti-hrv activity of compounds in cell-culture based assays. there are several methods for antiviral screening against hrv. the plaque reduction assay has been traditionally performed and accepted as the ''gold standard'' in antiviral testing. [137] [138] [139] however, this test is laborious, time consuming, and the evaluation is subjective. therefore, it is not suited for the routine antiviral testing. it was more and more replaced by methods based on quantification of protection from virus-induced cpe after drug treatment. so, the cpe in sample-treated and untreated cells has been compared by light microscopy. 137, 140, 141 but this evaluation is also subjective. another more objective approach is the spectrophotometric quantification of cpe results in neutral red or crystal violet uptake assays, 12,141-144 and the tetrazolium dye reduction method. 132, 145 it allows an excellent and rapid antiviral screening of large numbers of compounds using small amounts of extracts, natural, or synthetic compounds. active samples can be scheduled for additional testing using other assays e.g. virus yield or plaque reduction assays, and for studies on the mechanism of action. the activity of potential antiviral drugs has to be approved in vivo. because of the high degree of species-specific variations in icam-1 preventing infection by major group hrv, practical animal models have been absent for a long time. chimpanzees were infected with several hrv serotypes but without developing clinical signs. 133 hrv do not induce infection in rabbits, guinea pigs, and weanling mice injected with hrv by different routes. one minor group hrv, serotype 2, was adapted to grow in mouse fibroblasts and used in a mouse model of rhinovirus infection in which growth could be demonstrated. 146 based on the fact that the ldl receptor family is highly conserved between human and mouse, newcomb et al. examined whether hrv-1b, another minor group virus, may infect mouse airways in 6-to 8-week-old female c57bl/6 mice. 147 the authors demonstrated that this hrv serotype replicates and induces airway inflammation in vivo. these results strongly correspond to those of bartlett et al. who established three novel mouse models of rhinovirus infection in balb7c mice. 148 in the first model, 6-week-old balb/c mice were infected with hrv-1b. in the second model, transgenic balb/c mice, expressing a mouse-human icam-1 chimera, were inoculated with the major group hrv-16. rhinovirus-induced exacerbation of allergic airway inflammation is mimicked in the third model. due to the lack of a small-animal model for hrv infection until 2008, the experimental human challenge model has to be used to approve effects of potential antiviral drugs under controlled conditions in preclinical studies. volunteers were experimentally inoculated with various serotypes e.g. hrv-4, hrv-9, hrv23, hrv-29, and hrv-39 to examine the efficacy of potential antiviral drugs under standardized conditions. [149] [150] [151] [152] [153] [154] examples and results of these studies with capsid-binders, protease, and rna synthesis inhibitors, as well as interferons are described in the following sections. antiviral agents that inhibit virus attachment, capsid uncoating, protein and rna synthesis of picornaviruses are the best studied, 95, [155] [156] [157] and will be in the focus of this section. inhibition of virus attachment and/or uncoating interrupts the viral life cycle at its beginning and prevents hrv infection. options to prevent these early steps of the viral life cycle include (i) virus neutralization by hrv-specific antibodies, (ii) receptor blockade by antibodies directed against the cellular receptors icam-1 or ldl, (iii) by soluble receptor molecules, or (iv) by compounds interacting with the viral capsid. because of the high number of serotypes circulating often in parallel, application of hrv-specific antibodies is thought to be no promising approach for prevention or therapy of rhinovirus infection. in contrast, antibodies directed against the cellular receptor or soluble receptor molecules of major or minor group hrv could inhibit 90 and 10% of hrv serotypes, respectively. therefore, the strategy to prevent virus-receptor interaction by receptor antibodies or soluble receptor molecules has been extensively evaluated in vitro as well as in vivo. the antiviral activity of icam-and ldl-specific antibodies was confirmed in cell culture. 158, 159 furthermore, the prophylactic effectiveness and safety of intranasally administered rhinovirus murine icam-1 antibody was assessed in two double-blind, placebo-controlled, randomized studies of volunteers experimentally inoculated with hrv-39. 160 in the result, no toxicity related to antibody application was recognized. the higher dosage of 1 mg/subject of rhinovirus murine receptor antibody did not reduce overall infection or illness rates, but was associated with a 1-2 day delay in the onset of virus shedding and cold symptoms. viral titers and nasal symptoms were significantly reduced on the second day after challenge. in summary, the monoclonal antibody to the cellular icam-1 was demonstrated to be not effective enough. a new strategy was the creation of multivalent fab fusion proteins against icam-1. a new molecule, named cfy196 demonstrated a better avidity and in vitro potency against hrv over conventional mabs. 161 cfy196 is under development as nasal spray with the name of coldsol. antagonism of virus-receptor interaction was considered as another promising way to prevent hrv attachment to host cells. soluble forms of fully or truncated icam-1, [162] [163] [164] and ldl or vldl-receptor concatemers [165] [166] [167] exhibited antiviral activity against major and minor group hrv, respectively, in cell culture. soluble forms of icam-1 compete with receptor binding sites on the virus capsid, hinder an early infection event such as entry or uncoating, or directly inactivate hrv due to the formation of empty capsids. 163, [168] [169] [170] a soluble ldl receptor fragment neutralized viral infectivity by aggregation. 171 concatemers of the third ligand binding module of the vldl-receptor did not lead to viral aggregation but blocked the receptor binding sites and possibly inhibited viral uncoating by cross-linking the viral capsid subunits via multi-module binding. 166 the antiviral activity of a truncated, soluble form of icam-1 was proved in hrv-16 infected chimpanzee. 172 in randomized, double-blind, placebo-controlled trials, the safety and efficacy of intranasal administration of tremacamra, a soluble icam-1 in experimental hrv-39-induced colds in humans, was shown. 173 no further development was reported for these agents. 95 a further option to prevent virus attachment was described for low-molecular-weight compounds, the so-called capsid-binding agents, which enter the small hydrophobic pocket within viral capsid protein 1 beneath the icam-binding canyon of hrv. 174, 175 zhang et al. showed that drug may integrate into mature viruses by diffusion as well as into progeny viruses during assembly. 176 when hrv-14 and hrv-16 were grown in the presence of pleconaril, a higher occupancy occurred than when the drug was introduced into the alreadyassembled viruses. in doing so, capsid-binders induce conformational changes of the canyon of hrv-3 and hrv-14, hinder virus-receptor interactions, and prevent attachment to host cells. 105, 175, [177] [178] [179] in addition, uncoating of both hrv serotypes was shown to be inhibited as a result of a potential loss of flexibility of the viral capsid after drug binding. in contrast to hrv-3 and hrv-14, capsid-binding compounds did not prevent attachment of hrv-1a. results from x-ray studies showed that drug binding into the hydrophobic pocket of hrv-1a replaces the pocket factor but induces only very small conformational changes. 180 therefore, kim et al. suggested that the observed conformational changes are too small to affect receptor binding. but, capsid-binding compounds prevented attachment of hrv-16 possessing a pocket factor like hrv-1a without distinct deformation of the pocket. 102, 176, 181 further results from comparative antiviral studies with different capsid-binding compounds and hrv, representative for the major and minor group, did not reveal a correlation between inhibition of adsorption and receptor grouping or antiviral grouping. 182 the reasons for the difference in the mode of action of capsid-binding compounds related to attachment inhibition are not fully understood until now. taken together, inhibition of rna uncoating was found for all investigated serotypes after drug binding independent of receptor grouping whereas prevention of virus attachment was found to be an additional mode of action for individual viruses and/or drugs. till now, various potent compounds belonging to diverse chemical classes have been described as uncoating inhibitors. just to give an impression of diversity, the structures of disoxaril and pleconaril, 12,183-185 pirodavir and the oxime ether, 14, 141, 142, 186, 187 the isoxazole derivate compound, 19, 143, 188 the imidazole derivative sch 38057, [189] [190] [191] the chalcone ro 09-0881, 192, 193 4 0 ,6 dichloroflavan and isoflavan, 137, 194 the pyridine derivative mdl 20, 957, 195, 196 and the phenoxybenzene mdl-860 197, 198 that exhibit a potent anti-hrv activity (table ii) are shown as examples in figure 2 . they inhibit most of hrv serotypes and a couple of them also affect enteroviruses, however, with varying susceptibility. based on variability of susceptibility to capsid-binders of different length, hrv serotypes were classified into two different groups, a and b. 140 several of the given examples of compounds were also clinically tested. studying the development of clinically effective capsid-binders, the long road to the discovery of a clinically effective anti-hrv drug becomes apparent. one well-described example represents the discovery and optimization of capsid-binders from sterling winthrop pharmaceutical group, the so-called win compounds. 174 first inhibitors originated from juvenile hormone mimetics that demonstrated some activity against hrv-1a. determination of the x-ray structure of hrv-14 helped to understand the compounds' binding sites at the virus capsid. 103 results from subsequent x-ray studies of hrv-win compound complexes revealed the location and nature of binding sites and provided information concerning interactions within these sites. 175, 179, 180 this knowledge was used for optimization and design of new compounds. 199 optimized win compounds, for example disoxaril and pleconaril ( fig. 2) , consist of a methylisoxazol ring, a substituted phenoxy group, and a five-membered heteroatom ring and inhibit a broad spectrum of rhinoviruses and enteroviruses (table ii) . 12, [183] [184] [185] in 1985, the first broad-spectrum win compound disoxaril (win 51711) was tested in clinical trials. 139 the development of crystallurea in human volunteers treated with high doses as well as its low bioavailability (15%) prohibited subsequent development. thereafter, results from sar and qsar analysis were used to further enhance the potency and spectrum of activity. in 1992, another compound, win 54954, was clinically tested. it was not effective in humans infected with hrv-23 and hrv-29. 153 moreover, it was rapidly metabolized and induced a reversible hepatitis. consequently, the further clinical development was stopped. the better understanding of pharmacokinetic properties of capsid binders and synthetic chemistry efforts led to the discovery of pleconaril, an orally bioavailable, welltolerated capsid-binder that inhibits most rhinovirus as well as various enterovirus serotypes. 12, [183] [184] [185] in 2000, schiff et al. published the efficacy of pleconaril in an experimentally induced coxsackievirus a infection in humans. 200 in phase ii placebo-controlled, natural cold trials, the drug produced a moderate reduction of 1-1.5 day in the medium time to elevation of illness compared with placebo. 201 these results were confirmed in two subsequent pivotal studies. 202 besides the moderate clinical efficacy, these studies revealed that 13% of baseline isolates were not susceptible to pleconaril and 11% developed reduced susceptibility (defined as 10-fold increase in baseline value). in a subsequent study the relationship of pleconaril susceptibility and clinical outcomes in the treatment of common cold caused by rhinoviruses was demonstrated. 203 based on drug interaction, marginal treatment effect, and possibility of transmission of resistant viruses, the fda did not approve the applied oral administration of pleconaril for the treatment of common cold. the molecular mechanism of drug interaction of orally given pleconaril was shown to be based on hepatic cytochrome p450 3a activation. 204 to reduce adverse effects, shering-plough under license of viropharma completed a phase ii clinical trial with an intranasal formulation of pleconaril for the potential treatment of common cold in high-risk populations in 2007. the results were not published until now. pyridazine analogues developed by janssen research foundation represent another example for the long road to discovery of a clinically effective capsid-binder. 186 in 1992, the broad-spectrum activity of pirodavir ( fig. 2 ; table ii ) against rhinoviruses was published. 187 in the same year the results of a randomized, double-blind, placebo-controlled trail to assess the therapeutic efficacy of intranasal pirodavir in natural common colds were described. 205 possibly as a result of poor water solubility and rapid hydrolysis of pirodavir, no clinical benefit was found. the problem of ester hydrolysis was resolved by the development of oxime ether analogues of pirodavir by biota. an example is shown in figure 2 . like pirodavir these new analogues are potent inhibitors of rhinoviruses. 142 an advantage over pirodavir is their improved bioavailability. bta-798, an antiviral analogue with long half-life and good oral bioavailability, was scheduled to a phase ii clinical trial in 2008. the results have not yet been published. in summary, despite extensive research leading to the discovery of potent anti-hrv capsid-binders, no agent has been approved for prevention and/or therapy of rhinovirus-induced diseases so far. nearly, the same conclusion has to be drawn for protease inhibitors. because of their pivotal role for viral polyprotein processing and the high conservation of critical amino acids, 132 2a pro as well as 3c pro represent potential anti-hrv targets. results from cell culture-based assays provided evidence that inhibition of hrv replication is in principle possible. for example, processing of the hrv-2 polyprotein was prevented by pyrrolidine dithiocarbamate treatment in virus-infected hela cells. 206 in contrast to other enteroviruses, [207] [208] [209] [210] pretreatment of cell monolayers with different nitric oxide donors leading to s-nitrosylation of 2a pro and 3c pro had neither an effect on virus replication nor on hrv-induced il-8 elaboration. 211 the proteolytic activity of 2a pro of hrv-14 was specifically inhibited by two elastase-specific inhibitors, 212 and an antiviral peptide representing a derivative of the caspase inhibitor zvad.fmk. 213, 214 homophthalimides, e.g. ly353349 ( fig. 3 ; table ii) , were described as inhibitors of 2a pro as well as 3c pro . 215 in contrast to protease 3c, no structure-activity relationship studies have been reported for hrv 2a protease. moreover, protease 2a accomplishes only one cleavage in hrv polyprotein, while protease 3c performs all other cleavages. after elucidation of the crystal structure of 3c pro , 216 computer modeling of structural features of protease inhibitors became possible. 217 furthermore, structure-based design was used to develop mechanism-based inhibitors of the 3c protease with potent antiviral activity against multiple hrv serotypes. 218, 219 highly active compounds incorporate various michael acceptor moieties, irreversibly bind to 3c pro , and exhibit anti-hrv-14 activity in hela cells. 220, 221 structure-activity studies were performed to optimize protease inhibitors. 220, [222] [223] [224] [225] [226] these efforts resulted in the identification of a highly active anti-hrv compound, ag7088 (rupintrivir; fig. 3 ; table ii ) that entered clinical trials. in cell culture, ag7088 inhibited a broad spectrum of laboratory hrv as well as clinical isolates. 132, 183, 227 in a single-cycle, time-of-addition assay it demonstrated antiviral activity when added up to 6 hr after infection. 227 inhibition of hrv replication strongly correlated with reduction in the level of il-6 and il-8 release into cell supernatant, leading to the suggestion that this agent may not only block virus replication but also diminish symptoms. 228 the pharmacokinetics and safety of rupintrivir were proved in two double-blind, randomized, placebo-controlled studies. 229 intranasal rupintrivir, administered as single doses of 4 and 8 mg or every 3 hr, six times per day, for 7 days, was safe and well tolerated. three double blind, placebo-controlled clinical trials were conducted to assess rupintrivir nasal spray (2% solution) for prevention and treatment of experimentally induced rhinovirus colds in healthy volunteers. 230 rupintrivir prophylaxis reduced the proportion of subjects with positive viral culture by 26% and viral titers but did not decrease the frequency of colds. drug treatment led to the reduction of the mean total daily symptom score by 33%. subjects receiving rupintrivir also demonstrated significantly lower viral titers and rna levels than placebo-treated subjects on days 2, 3, and 5 and on days 2 and 3, respectively. there was no influence on the proportion of subjects with positive viral culture and the frequency of colds. clinical development was terminated because rupintrivir did not act in a subsequent natural infection study in patients. 231 in parallel research efforts, an orally bioavailable inhibitor of table ii) , was discovered. 225, 231 like rupintrivir, this compound is an irreversible inhibitor incorporating a michael acceptor moiety that forms a covalent bond with the 3c protease active site cysteine. it demonstrated an antiviral activity against all hrv and related picornaviruses tested. 231 in a phase 1 clinical study, compound 1 was shown to be safe and well tolerated. according to a publication of patick, no further clinical development was planned for this compound. 95 the blocking of viral rna synthesis during replication represents another site for chemotherapeutic interdiction. it was shown that, rhinoviral rna can be targeted in a sequence-specific manner by deoxyribozymes, 232 morpholino oligomers, 233 and small interfering ribonucleic acids. 234 the efficacy of the latter two approaches was confirmed in cell culture. in addition, 2-furylmercury chloride ( fig. 4 ; table ii ), 235 table iii) , 236 and pyrrolidine dithiocarbamate (fig. 4 ) interfered with rhinoviral rna synthesis and inhibited hrv replication in cell culture-based assays. 206, 237 the nucleoside analog ribavirin ( fig. 4 ; table ii ) that inhibits a broad spectrum of rna as well as dna viruses acts also against hrv-2 in hela cells. 238, 239 the cellular inosine monophosphate dehydrogenase that controls de novo synthesis of purine nucleosides represents the principal target in the mode of action of ribavirin. 240 moreover, when ribavirin is incorporated into picornavirus rna, it pairs equally well with either uracil or cytosine inducing mutations that can be lethal to rna viruses. 241 further identified mechanisms of action for ribavirin include inhibition of genomic rna capping, enhancement of host t-cellmediated immunity against viral infections through helping to switch the host t-cell phenotype from type 2 to type 1. 242 another compound with potent anti-hrv activity in vitro is enviroxime ( fig. 4 ; table ii ), a benzimidazole derivative. 243, 244 it inhibits viral plus strand rna synthesis. 245 in particular the 3a protein, which is involved in the initiation of plus strand rna synthesis, was implicated as likely target of drug activity. 246, 247 however, results from another study suggest that enviroxime targets a complex of proteins and/or cellular factors and that the exact mechanism remains to be studied. 248 although there was a statistically significant reduction in clinical score in a prophylactic study with hrv-9-infected volunteers, 152 enviroxime failed in experimentally induced hrv-4 and hrv-39 infection, 149, 151 and in clinical studies, 248-250 because of poor bioavailability and side effects. in an attempt to overcome the marked hydrophobicity, water insolubility, and toxicity, wyde et al. incorporated enviroxime into liposomes and then tested the anti-hrv activity and toxicity of the liposome-incorporated enviroxime in cell culture. 251 the liposome preparation of enviroxime inhibited hrv-1a and hrv13 as effective as the parent compound and was 10-to z50-fold less toxic. in contrast to free enviroxime, the liposome preparation was readily and successfully delivered by small-particle aerosol to the upper and lower respiratory tract of mice. in another attempt to overcome the disadvantages of enviroxime, several benzimidazole as well as nonbenzimidazole analogs were synthesized and studied. [252] [253] [254] [255] even though some compounds were better bioavailable and could be administered orally, 254 none of these compounds was tested in clinical studies. besides virus-specific targets, cellular inhibitors like interferons may represent a therapeutical approach. among other activities, interferons exhibit antiviral activity. the advantages of interferon application include the broad spectrum of activity and low risk of resistance development. human leukocyte and fibroblast as well as recombinant human a interferons prevent the hrv-induced cpe in cell culture whereas a variation in sensitivity was observed. [256] [257] [258] intranasally applied recombinant interferon a and interferon b have been shown to be effective in humans when provided prophylactically both in experimental and natural rhinovirus colds. [259] [260] [261] [262] [263] [264] significant reductions in illness frequency, mean symptom score, nasal secretion weights, and frequency of virus isolation were observed. in contrast, recombinant interferon g did not prevent hrv infection or illness and may enhance the symptoms. 265 little to no therapeutic effect was found in patients with common cold after interferon treatment. 150, 266 moreover, blood-tinged mucus and nasal bleeding were described as side effects. 263, 267 combining interferons with dichloroflavan, enviroxime, chalcone ro-09-0410 produced synergistic increases in antiviral activity in vitro against hrv-2 and hrv-9. 268 an attempt to demonstrate synergy between the anti-hrv effect of recombinant human rhuifn a and enviroxime in hrv-9 and hrv-14-infected volunteers failed. 269 according to the authors, the main reason for this failure may be the rapid removal of enviroxime from the nose when given intranasally. a. impact of natural products nature provides an astonishing pool of secondary metabolites biosynthesized from living organisms such as plants, fungi, protozoan, insects, and other animal sources. in contrast to synthetic compounds, natural products are characterized by an overwhelming chemical diversity. previously, the chemical diversity space between these two groups was evaluated with respect to drug substances by feher and schmidt. 270 it is shown that combinatorial compounds densely populate a small area, whereas natural products cover a wider range quite similar to the chemical space occupied by drug substances. the authors accordingly suggest that combinatorial libraries that mimic the distribution properties of natural products might be more biologically relevant. one may assume that secondary metabolites evolved as reaction to their target receptors related to defence, protection, attraction, and signalling. these adaptation processes have enriched not only the metabolites' structural diversity but have also optimized drug-like metabolic traits likely to have favorable pharmacokinetic properties. 271, 272 it is this evolutionary concept that gives the pool of natural products the greatest source of scaffold diversity with molecules of biological relevance. newman and cragg analyzed the number of drugs approved between 1981 and 2006 and circumstantiated that especially the anti-infective area is strongly dependent on natural products and structures derived from natural scaffolds. 273 the anti-infectives including the antiviral vaccines are with 22.8% or 230 launched drugs by far the major category with only about 30% being synthetic in origin. from 1981 to 2006, 78 vaccines and antiviral drugs have been approved. excluding the high number of vaccines (25) and biologicals (12) , most of the 41 small antiviral molecules are based on nucleoside structures or on peptidomimetics; only 16.7% are classified as totally synthetic drugs. however, till now, neither a synthetic nor a naturally derived anti-hrv drug substance has been approved for the treatment or prevention of hrv infections. intensive research and development efforts in the field of natural products revealed several inhibitors of viral attachment and entry, and inhibitors of viral protease from natural sources. the efficacy of natural products is not only reflected by statistics of launched drugs but also by empirical knowledge gained over centuries by successful application of naturalbased ethnomedicinal products such as plants, culinary herbs, and spices. phytochemical and pharmacological work performed with ethnomedicinal anti-hrvs mainly from plants revealed a high number of active metabolites from different chemical classes, e.g. coumarins, flavonoids, alkaloids, quinones, terpenoids, polyphenols, and polysaccharides. natural products include complex extracts and their chemical entities, which are biosynthesized by nature. for an unambiguous presentation of anti-hrv natural products it is of prior importance to first distinguish between a single chemical entity from nature, i.e. an isolated, purified natural compound, on one hand, and a natural preparation comprising hundreds to thousands of constituents, mainly secondary metabolites, on the other hand. if natural preparations are derived from plants, they might also be labelled as botanicals, phytoceuticals, or phytotherapeutic agents. these multicomponent preparations might show a varying profile of their constituents depending on the used species, origin, collection time, plant parts, extraction procedures, preparation methods, and manufacturing processes, just to mention a few important elements. these parameters affect the final product in terms of the qualitative and quantitative composition of chemical constituents, which may have an impact in biological activity. accordingly, studies performed with phytochemically not specified extracts or nonstandardized preparations often suffer from irreproducible and incomparable results a wide variety of natural preparations showed to be acting therapeutically in hrv and other viral infections with often complementary and overlapping antiviral mechanisms of action. [274] [275] [276] most of these remedies are described in ethnopharmacological sources or handed down for generations. they usually consist of simply prepared natural items whose chemical composition is complex. many of the contained secondary metabolites, possibly active principles, have never been examined chemically or biochemically using modern medical knowledge. they are however components of plant medicines, which have stood the test of time and as such may offer clues of great interest to medicinal chemists. a clear advantage of the application of these products is their absent or relatively low toxicity due to a usually long-term empirical trial. although the knowledge of the immuno-pathogenesis of rv-induced diseases remains limited, the host defense function of the airway epithelium plays an important role in the innate-immune response to hrv-infection. 277 host cells respond by the production of mediators with antiviral activity such as type i interferons and nitric oxide, and produce cytokines and chemokines that influence the subsequent induced innate-and specific-immune response. these processes are beneficial in facilitating clearance of virus from the respiratory tract, but also cause immuno-pathology. following hrv-infection, disease severity is dependent on direct, harmful effects of the virus as well as tissue damage as a result of the host antiviral immune response. accordingly, a number of agents with phenomenological effects against common cold have shown to exert their activity more in the field of regenerating tissue damage than on a direct anti-hrv effect. several herbal remedies consisting of a multitude of secondary metabolites from different chemical classes may attribute in a beneficial way for the treatment of common cold by reducing symptom severity and duration due to their immune-modulating, anti-oxidative, and anti-inflammatory properties. beside these commonly observed bioactivities of natural products, multicomponent mixtures like botanicals often show overlapping symptomatic effects as well as synergistic and/or additive properties. thus, it is a challenging endeavor to track down an observed phenomenological effect of a complex mixture on a molecular level. the following section explores the significance and current knowledge of selected botanicals for the prevention and therapy of common cold. questions about (1) clinical evidence of efficacy, (2) the constituents or at least the chemical classes that are involved in the observed anti-hrv effect, and (3) the involved pharmacological targets were covered as far as possible. echinacea preparations include expressed juice from aerial parts as well as extracts of roots or aerial parts, or both, from one or more species of the genus echinacea (e. angustifolia, e. purpurea, and e. pallida). they are the most recognized botanicals for prevention and treatment of common cold and flu, and account for the second top-selling herbal products in the us-market. 278 accordingly, echinacea has come under much scientific scrutiny. the high number of studies dealing with the effectiveness of echinacea for preventing and treating the common cold from clinical trials was recently reviewed by woelkart et al. 279 the authors summarized the findings of the meta-analyses regarding the 16 randomized controlled trials evaluated in the cochrane database, 280 the 14 randomized clinical trials analyzed by shah et al., 281 and the experimental hrv-infection studies pooled by schoop et al. 282 to sum up, the clinical data on echinacea so far are not fully consistent, mainly based on problems inherent in assessing the efficacy of echinacea preparations, such as lack of comparability of available preparations, study design, and outcome. nevertheless, the meta-analyses showed some evidence that preparations based on the aerial parts of echinacea purpurea might be effective for the early treatment of colds in adults. 280 echinacea showed to decrease the odds of developing the common cold by 58% and the duration of a cold by 1.4 days. 281 similarly, the evaluation of three induced rhinovirus prevention studies revealed the odds of experiencing a clinical cold were 55% higher with placebo than with echinacea. 282 stepping into a molecular level, several constituents found in echinacea species could potentially affect the symptoms of common cold. chemically identified substances include polysaccharides and glycoproteins, caffeic acid derivatives (especially cichoric acid and echinacoside), and lipophilic polyacetylenes and alkamides. pharmacological studies have shown that cichoric acid, alkamides, glycoproteins, and polysaccharides possess immunomodulatory activity. additionally, alkamides have been reported to exert not only antiinflammatory effects but also cannabinomimetic properties, which are suggested as molecular mode of action of echinacea alkamides as immunomodulatory agents. 283 raduner et al. showed that some echinacea alkamides exert cannabinoid type 2 receptor-dependent and independent immunomodulatory effects on cytokine expression. 284 different echinacea constituents were evaluated for their anti-oxidative effects measuring the inhibition of in vitro cu(ii)-catalyzed oxidation of human low-density lipoprotein. thereby, the major caffeic acid derivatives, cichoric acid and echinacoside, showed the highest anti-oxidative effects, which was even higher when combined with a natural mixture of alkamides. 285 sharma et al. used cytokine antibody arrays to investigate the changes in the pro-inflammatory cytokines and chemokines released from human bronchial epithelial cells exposed to hrv 14. 286 application of two chemically characterized echinacea extracts showed a reversion of the stimulated release of numerous pro-inflammatory cytokine-related molecules, e.g. for the cytokine il-6, and the chemokines il-8 and eotaxin. in a similar study, an echinacea extract rich in polysaccharides and another rich in alkamides and caffeic acid derivatives were as well able to neutralize the effects of hrv-infected epithelial cells. 287 using gene expression analysis both studies revealed the anti-hrv benefit of echinacea preparations being involved in multiple immune response signaling pathways. taken together, the numerous pharmacological findings from literature, the potential of echinacea preparations, and their constituents to combat or prevent common cold can be deduced to immune modulating, anti-inflammatory, and anti-oxidative properties that may also act in some combination of these event, rather than acting directly on hrv. garlic cloves have been used traditionally to treat a number of infectious diseases. however, only few confirmatory studies have been published regarding the traditional antiviral uses. the clinical effectiveness of garlic on the prevention of common cold was investigated by josling in 2005, who published a double-blind, placebo controlled study assessing 146 patients more than a 12-week treatment period with an allicin-containing garlic supplement. 288 common cold infections and symptoms were recorded in a daily diary. patients in the treatment group had significantly fewer colds than patients in the placebo group (24 vs. 65, po0.001) who also had a longer duration of symptoms (5.01 vs. 1.52 days, po0.001). as soon as the garlic is chewed, cut, or pressed, its main ingredient, the sulphur containing alliin, is broken down by the enzyme alliinase to the thiosulfinate allicin. by steam distillation allicin is transformed to diallyl disulfide and diallyl trisulfide that are responsible for the distinctive smell of garlic. further, allicin transformation compounds, such as e-and z-ajoene, are not found in fresh garlic, but in lipophilic extracts. by investigation of different garlic extracts and isolates against a number of different human pathological viruses, weber et al. could show that allicin was the most active virucidal component from fresh garlic and fresh extracts. 289 results of the direct pre-hrv-2-infection incubation assay let suggest allicin to bind to the viral protein capsid, leading to a subsequent inhibition of viral adsorption and penetration. although the garlic thiosulfinates are endowed with significant cytotoxicity, the antiviral effects were obtained in nontoxic concentrations. 289 beside the direct anti-hrv effect of fresh garlic extract and allicin, a number of human immune functions were found to be enhanced in vitro by aqueous garlic extract, its polar, and thiosulfinate fractions. 290 in north america, panax quinquefolium, the ginseng species indigenous to both canada and the united states, has been a popular herbal remedy to combat stress, and to modulate both natural and acquired immune responses. american ginseng root extracts, rich in poly-furanosyl-pyranosyl-saccharides, have been found efficacious in the prevention of upper respiratory infections in immunocompetent healthy adults. 291, 292 in a randomized, double-blind, placebo controlled trial, 200 mg of a proprietary american ginseng root extract was given to 43 community-dwelling elderly adults (age 465 year) twice a day more than a ''cold and flu'' season period of 4 months. one month into the study, all participants received an influenza vaccination. during the first two months, no significant differences in duration and incidence were observed when compared to placebo. however, during the last two months significantly fewer subjects of the ginseng group reported acute respiratory syndromes than the placebo group (32 vs. 62%). additionally, the duration of respiratory symptoms was reduced by 55% in the ginseng group. 291 in a similarly arranged trial, 323 healthy adults (ages 18-65 years) with a history of at least two colds the previous year commenced a 4 month study at the beginning of a cold and flu season. 292 they received two 200 mg capsules daily of standardized american ginseng root extract or a placebo. outcomes measured were number of colds including symptom severity and total number of symptomatic days. a therapeutic effect was reported regarding symptom severity and fewer symptom days that were 31 and 34.5% lower in the ginseng group than in the placebo group. a phase ii randomized, controlled trial of 2 dosing schedules of american ginseng root extracts, rich in poly-furanosyl-pyranosyl-saccharides, evaluated the safety, tolerability, and efficacy in a pediatric population already suffering from an upper respiratory tract infection. the results showed no serious adverse events and a good tolerability of both ginseng doses; however, frequency and severity of symptoms were not significantly different among each of the three treatment groups, i.e. standard dose, low dose, and placebo. 293 the most prominent constituents of the genus panax are the triterpene saponins ginsenosides. they are known to have numerous pharmacological activities such as anti-cancer, anti-diabetes, antiviral, and anti-atherosclerosis effects. some compounds of this chemical class showed to be responsible for the immunostimulant activity of ginseng. 294 on the other hand, the efficacy of a polysaccharide-rich extract of american ginseng was compared with an extract rich in ginsenosides on systemic and gut-associated immune function. the authors of this study investigated the lymphocytes isolated from spleen, mesenteric lymph nodes and peyer's patches, and immune cell proportions and cytokine production from sprague-dawley rats. they could show that the polysaccharide-rich ginseng extract modifies the rats' systemic immune responses and affects the gut-associated immunity in a manner distinct from that of the ginsenoside-containing extract of american ginseng. 295 a direct antiviral activity of ginseng constituents could be attested for the polysaccharides on rotavirus infection in ma104 cells. the triterpene saponins, however, did not exhibit any rotavirus infection-inhibitory activity in this study. 296 a moderate in vitro virucidal effect (id 50 62 mm) of the ginseng saponin chikusetsusaponin iii against herpes simplex virus type i was detected by fukushima et al. this compound exhibited an intracellular inhibitory activity, but could only marginally affect the viral proteins postinfection. 297 the ancient chinese formula bu-zhong-yi-qi-tang (japanese name hochu-ekki-to) is a traditional herbal medicine in china and japan that is composed of ten species of medicinal plants, namely astragali radix, atractylodis lanceae rhizoma, ginseng radix, angelicae radix, bupleuri radix, zizyphi fructus, aurantii nobilis pericarpium, glycyrrhizae radix, cimicifugae rhizoma, and zingiberis rhizoma. this formula is reported to have various immunomodulatory, [298] [299] [300] and anti-inflammatory activities. 301 yamaya et al. recently investigated the effects of hochu-ekki-to in cultures of human airway epithelial cells infected with hrv-14. 302 the output of virus, associated levels of viral rna, and the production of icam-1, cytokines and acidic endosomes in cells were measured. in airway epithelial cells hochu-ekki-to was able to decrease virus output and susceptibility to hrv infection by decreasing icam-1 and by blocking the entry of viral rna into the cytoplasm from the endosomes. glycyrrhizin, a major component of one herbal ingredient of hochu-ekki-to, i.e. glycyrrhiza glabra, was able to reduce supernatant virus titers dose-dependently, with a maximum effect between 0.12 and 0.6 mm. however, no clinical trials with representative numbers of subjects are published so far. the human rhinovirus k 63 5. umckaloabo (pelargonium sidoides) p. sidoides and p. reniforme form the origin of the popular drug umckaloabo. this herbal remedy from south africa has found entrance in western medicine mainly as aqueous ethanolic root extract from p. sidoides for the treatment of infections of the respiratory tract. the efficacy of umckaloabo compared with placebo has been evaluated in 103 adults suffering from common cold by lizogub et al. 303 the applied herbal preparation was well tolerated by the patients. the study demonstrated only a weak efficacy of umckaloabo compared to placebo after 5 days. after 10 days, however, the p. sidoides extract significantly reduced the severity of symptoms and shortened the duration of the common cold compared with placebo. just recently, timmer et al. selected randomized controlled trials examining the efficacy of p. sidoides preparations for the treatment of various acute respiratory infections and analyzed their efficacy and safety. 304 the authors concluded that umckaloabo may be effective in alleviating symptoms of acute rhino-sinusitis and the common cold in adults. it may be effective in relieving symptoms in acute bronchitis in adults and children, and sinusitis in adults. reliable data on the treatment for other acute respiratory infections however were not obtained. identification of the metabolites from umckaloabo revealed a high number of different chemical classes, such as phenolic and cinnamic acids, tannins, flavonoids, and coumarins. antibacterial activities of umckaloabo against different pathogens have been reported. phenols, coumarins, and tannins have been identified to contribute with moderate antibacterial activities, however, cannot explain the effect of the whole extract (reviewed by kolodziej 305, 306 ). additionally, p. sidoides extracts have been reported to significantly activate the nonspecific immune system by induction of tnf and no-release, and ifn-like activities. 305 these effects are assumed to contribute to the controversially discussed potential of p. sidoides extract for the treatment of upper respiratory tract infections. only one study reports a direct antiviral effect, i.e. a clear dose-dependent anti-herpes simplex virus acitivity for the aqueous root extract of p. sidoides. 307 further pharmacological studies are needed to elucidate potential direct anti-hrv properties of umckaloaba and its constituents. carrageenan, a mixture of different polysaccharides, which is mainly extracted from red seaweeds, has been extensively used in food, cosmetic and pharmaceutical industry as a thickener and gelling agent. it has previously shown an antiviral efficacy against several viruses. 308, 309 in a recently published study, lambda-, kappa, and iota-carrageenan were investigated for their anti-hrv inhibiting potential. at a concentration of 200 mg/ml iotacarragenan, a sulphated polysaccharide, was able to fully inhibit virus-induced cell death in hrv-2 infected hela cells. 310 based on their studies, grassauer et al. concluded that iotacarrageenan is effective against different hrv-serotypes on primary human epithelial cells. it is hypothesized by the authors that iota-carrageenan might create a hostile environment for hrv and thereby block viral entry and replication. because of its safe application and proved in vitro efficacy, iota-carrageenan deserves consideration as a candidate for clinical trials for prevention and therapy of hrv-induced common cold. the level of knowledge on the impact of the six botanicals on hrv-infection discussed above is different and heterogeneous. the best studied herbal remedy associated with common cold, i.e. echinacea, showcases the innate problem connected with multi-component mixtures: starting from the late nineties till june 2009 some 100 original articles have been published to this topic and tried to elucidate questions concerning efficacy, molecular mechanism, and bioactive ingredients of echinacea. although some evidence is provided for the effects of extracts, chemical classes as well as well-defined constituents on specific targets and pathways, the findings cannot be deduced to a common denominator. further, results from clinical trials often suffer from lack of comparability, because of using different study designs, outcome measures, and overall the application of different preparations. 279 a proper quality analysis and characterization of the preparation under investigation is mandatory and should follow the recommendations and guidelines for reporting clinical trials for herbal medicine. 311 as underlined before (sections 5.1. and 5.2.), the chemical complexity of a natural preparation might be beneficial in terms of synergistic, additive, and overlapping effects caused by the multitude of evolutionary trimmed metabolites, which may attribute with modulating multi-target effects. on the other side, exactly this fact is hardly compatible with the proper assignment of an activity to a defined chemical entity according to western medical practise. in contrast to a single compound (synthetic or naturally based), the chemistry of a botanical is not only complex but also varying. the analytical profile and in term the pharmacological profile of the investigated samples can differ substantially. accordingly, the quantitative and qualitative comparison of different studies resulting from botanicals is by far more complex than those performed with pure single compounds, and may also explain why so little emphasis from pharmaceutical industry has been put into the further development of even promising natural preparations. in general, the search for potent, selective, nontoxic compounds that might be developed further to a drug substance is a multidisciplinary, time-and cost-consuming process. therefore, strategies for a target-oriented discovery of lead-structures either from nature or synthesis are in high demand. some of them will be discussed in the following section, providing examples from anti-hrv research. as already mentioned, nature provides an extremely rich pool of bioactive natural products. it is however a challenging endeavor to find exactly those compounds that show an activity on the focused target. in natural product research hints from folk medicine are a valuable starting point to dig for lead structures of certain interest. the majority of active principles from higher plants has been discovered as a result of ethnopharmacologically directed pharmacognostic research. 312, 313 oral or written indications for a beneficial application of a natural material first need a critical evaluation as to the selection of the correct material, its medicinal preparation, the kind of application, and overall the pharmacological profile. a rational criticism of often anecdotal efficacy from traditional medicine is a mandatory attitude to avoid overinterpretation of handed-down information. 314 in case of pretended anti-hrv remedies, the reported biological efficacy obviously suffers from being restricted to respiratory diseases, which might be caused by a panel of bacterial or viral infections. thus, an approved remedy may affect the microbes, or show an immune modulating or even antiinflammatory effect, or a combination of these. the holistic access is an innate character of ethnopharmacology and needs to be tracked down to the specifically involved target/s. in a recently published study focusing on the discovery of hrv-capsid binders from nature using a pharmacophore-based virtual screening of an ethnopharmacologically biased 3d-multiconformational database, some 30 secondary metabolites were predicted to act as capsid-binding inhibitors of hrv. 144 for an in depth phytochemical and pharmacological investigation, it was mandatory to focus on one promising natural material. thus, we consulted the ethnobotanical source materia medica, which was written by pedanius dioscorides in the 1 st century ad. the treatise consisting of five books comprises some 1,000 or so drugs derived from minerals, animals, and the majority of them from plants (800). it represents a great repository of botanical, medical, and pharmacological lore. scrutinizing the natural materials underlying the obtained virtual hits we came across asafetida, which is a gum resin gained from the roots of a variety of foul-smelling ferula species from the apiaceae family. based on the descriptions given in the materia medica there is strong evidence that the juice (i.e. resin) of the popular ancient silphion originating from media and syria corresponds to asafetida (book iii, cap. 80). 315 yielded by incision of the root and stalk and frequently mixed with sagapenon, i.e. the resin of f. persica willd (book iii, cap. 81), it is reported to be effective in the context of upper respiratory diseases, e.g. ''for chronic harshness of the throat,'' ''it clears the voice,'' ''shrinks the uvulas,'' ''suitable for a cough,'' ''for pleurisy,'' ''for chest pain;'' sagapenon is described as follows: ''it clears thick matters from the lungs,'' ''given to those who are chilled.'' 315 these descriptions finally helped to prioritize those virtual hits, which have been reported to be constituents of asafetida. 316 the pharmacological investigation of asafetida and its constituents farnesiferol b and c ( fig. 5 ; table iii ) revealed a distinct anti-hrv-2 effect in the low micromolar range using a cpe inhibitory assay. 143 the results of this study provided a rationale for the ancient usage of asafetida for upper respiratory tract infections. on the other hand, the traditionally manifested evidence for asafetida for the treatment of common cold symptoms substantially helped in the selection of this plant material in the search for anti-hrv capsid binders. 144 typically, an ethnopharmacologically based discovery of an active (anti-hrv) extract is followed by a bioassay guided fractionation, and the isolation of those constituents that are responsible for the extracts' bioactivity. the concept of a bioassay-guided approach is the fractionation accompanied by simultaneous detection of the activity during the separation steps, which results in a continuous enrichment, and finally in the isolation of the active ingredient/s. in this way a large number of anti-hrv agents from natural sources have already been discovered. semple et al. investigated the active principle of the asteraceae plant pterocaulon sphacelatum, which has been used in traditional medicine of aboriginal people of australia as a favored treatment for respiratory infections, especially colds. by means of an antiviral activity-guided fractionation measuring the poliovirus-induced cpe assay, the authors identified the flavonoid 3,7,3 0 -trimethoxy-5,6,4 0 -trihydroxyflavone, i.e. chrysosplenol c ( fig. 5 ; table iii ) as potent and specific inhibitor of the picornaviral replication. 6,7,8-trimethoxycoumarin ( fig. 5 ; table iii) was also isolated as a major constituent from the ethanolic extract of p. sphacelatum, but showed no activity against poliovirus. 317 interestingly, this coumarin exhibited a significant effect in the hrv-2-induced cpe assay in a recently performed virtual parallel screening study performed in our laboratory. 318 in contrast to the isolated coumarin, chrysosplenol c was already known as a member of the 4 0 -hydroxy-3-methoxyflavones, which represent potent and specific inhibitors of picornaviral, especially rhinoviral replication. [319] [320] [321] in 1993, vanden berghe, haemers, and vlietinck provided a profound survey of antiviral agents from higher plants, and demonstrated the impact of ethnobotanical knowledge in their search for antiviral compounds from african medicinal plants. the selection of investigated plant species was mainly based upon their use in the treatment of viral diseases by african traditional healers. 320 the antiviral activity of 100 different plant species belonging to 33 families was investigated; thereof 21 species exhibited prominent antiviral properties against one or more of the tested viruses. the most pronounced activity against picornaviruses was recorded within the genus euphorbia. all compounds detected as antiviral constituents from the respective extracts were identified as 3-methoxyflavone derivatives, especially 3-methylethers of quercetin and kaempferol ( fig. 5 ; table iii ). they showed no significant cytotoxicity and were highly active in tissue culture against all human picornaviruses. in tissue culture, cells infected with different picornaviruses (among them also hrv) no cpe was observed, when cells had been treated with 2 mg/ml of these 3-methoxyflavones. 320 the selection of natural materials based on ethnopharmacology is a profound rationale for lead structure discovery and highly superior to random selection. this however rarely applies to marine organisms, fungi, and microbes. although these organisms are esteemed as highly valuable source for bioactive metabolites, 322 hardly any records from folk medicine are given for them. a medium-sized activity screening using a robust cell-based or in vitro-assay with reasonable effort as to time and costs is a strategy to get a first insight into the antiviral activities of extracts, fractions, and compounds from synthesis or nature. for the discovery of novel naturally based hrv 3c-protease inhibitors, singh et al. used a small peptide containing q-g scissile bond as substrate for the in vitro screening of extracts. the authors isolated the novel benzoisochromanquinone (1)-thysanone ( fig. 5 ; table iii ) from an extract of the fungus thysanophora penicilloides with potent hrv 3c-protease inhibitory activity. 323 a continued screening revealed a pronounced hrv 3c-protease inhibitory activity for the extract of the chinese herb polygonum cuspidatum. by bioassay-guided fractionation 2-methoxystypandrone ( fig. 5 ; table iii ), a naphthoquinone, with an ic 50 value of 4.6 mm, was isolated from the plant material. the total syntheses of this natural compound and further analogues allowed for a structure-activity relationship, and particularly the comparison between activities of ortho-vs. para-quinones. to measure the selectivity of the compound series against cystein proteases other than hrv 3c-protease, the compounds were evaluated against papain. the simple 9,10-phenanthraquinone ( fig. 5 ; table iii ) was the most active compound of the series and showed an ic 50 value of 1.4 mm with a distinctly higher degree of selectivity than 2-methoxystypandrone. 324 a cpe reduction assay was applied for the identification of raoulic acid, a bicyclic c25 terpene acid ( fig. 5 ; table iii ) isolated from raoulia australis (asteraceae). raoulic acid exerted an antiviral activity against coxsackie virus b3, b4, enterovirus 71, and hrv-2 and -3 with ic 50 values in the submicromolar range. no activity was recorded against influenza a and b viruses. 325 in the course of the systematic screening of microbial and natural products for anti-hrv activity, ishitsuka et al. identified 4 0 ,5-dihydroxy-3,3 0 ,7-trimethoxyflavone ( fig. 5 ; table iii) from the leaves of the chinese medicinal plant agastache rugosa (lamiaceae) as natural compound with high activity against all picornaviruses except mengovirus. the authors synthesized the orally active 4 0 ,5-diacetyloxy-3,3 0 ,7-trimethoxyflavone and performed investigations in tissue cultures and in mice to determine the compound's mode of action. this was assumed to be the process of viral replication, thus located between viral uncoating and initiation of viral rna synthesis. 326 the activity of flavan ( fig. 5 ; table iii ) was discovered serendipitously during a screening program by using a plaque inhibition assay. 194 based on these results, bauer et al. synthesized 4 0 ,6-dichloroflavan (bw863c, fig. 2 ; table ii) , which revealed an activity against a number of hrv serotypes in the range between 0.007 and 10 mm. as soon as an active lead compound is identified it is of utmost importance to scrutinize the derivatives' activity to (i) obtain insight into the chemical requirements mandatory for the focused biological activity, (ii) improve the compound's pharmacological profile in terms of potency, selectivity, cytotoxicity, etc., and to (iii) improve its bioavailability. the nonphenolic aporphine alkaloid glaucine is a prominent constituent of the aerial parts of gaucium flavum (papaveraveae). in a recently published study, spasova et al. investigated the antiviral potential of glaucine ( fig. 5 ; table iii) , glaucine derivatives, and its semi-synthesized 3-aminoethylglaucine cinnamoyl-and hydroxycinnamoyl amides. beside the anti-oxidative potential of the newly synthesized compounds, they all exerted an antiviral activity against the replication of hrv-14. the best anti-hrv activity was observed for oxoglaucine ( fig. 5 ; table iii; ic 50 table iii; ic 50 15 mm, si 10.3 and ic 50 13 mm, si 11, respectively). 327 the early findings of the anti-hrv active naturally derived 3-methoxyflavone inspired chemists and pharmacologists in the synthesis and the pharmacological evaluation of derivatives thereof decorated with various substitution patterns. several reports published during the last two decades reviewed the findings of antiviral flavonoid research. 320, 328, 329 by investigating the antiviral activity of a wide variety of naturally occurring flavonoids, tsuchiya et al. found chrysosplenol b and c ( fig. 5 ; table iii ) contained in chrysosplenium plants, and axillarin ( fig. 5 ; table iii ) as potent anti-hrv agents. based on their findings, the flavone skeleton decorated with a methoxy group in position 3 and a 5-hydroxyl group revealed as mandatory for an anti-hrv activity. 319 a series of antipicornaviral 4 0 -hydroxy-3-methoxyflavone derivatives was synthesized by de meyer et al. in order to establish a structure-activity relationship. thereby, different substitution patterns of the a-ring system with methyl, hydroxy, methoxy, halo, nitro, and amino was performed. their activity against polio and hrv was compared with those of naturally occurring flavonoids. further, the importance of the 4 0 hydroxyl-group and of the 3-methoxyl-group was confirmed by investigation of different derivatives lacking these features. 321 the results showed that 4 0 -hydroxy-3-methoxyflavones with a monosubstituted a-ring are less active than the corresponding compounds having a polysubstituted a-ring. within the tested series of compounds, 4 0 ,7-dihydroxy-3-methoxy-5,6-dimethylflavone emerged not only as noncytotoxic but also as most potent substance in both antiviral test systems. the lowest concentrations for this compound that protect 50% of the cells from cpe of 12 hrv serotypes were in the range from 0.016 to 0.5 mg/ml. in contrast to quercetin, this flavone was also reported to have no mutagenic properties (measured up to 2.5 mg/plate) in a short-term microbial assay. 321 the mechanism studies performed with 3-methoxyflavones have shown an interference with an early stage in the viral rna synthesis; no induction of resistance was observed. 320 in contrast to this mode of action, the anti-hrv chalcones and flavans are reported to interact directly with specific sites on the viral capsid proteins, thereby preventing uncoating and the consequent liberation of viral rna. 193, 330, 331 due to its anti-hrv potency, low toxicity, and promising bioavailability, dichloroflavan was evaluated for its protective efficacy against experimental hrv-infection in two clinical, double-blind, placebo-controlled trials. however, the drug candidate failed either when administered orally or intranasally. 332, 333 unfortunately, till now no clinical trials evaluating the efficacy of 3-methoxyflavones in common cold have been performed. the common idea of all computational approaches is to extract knowledge from a more or less large set of data in order to make predictions of new events. 334 within the lead discovery process, computational approaches, such as virtual screening, docking, quantitative structure-activity relationship, have largely enhanced the impact of computational chemistry and nowadays chemoinformatics plays a predominant role in drug research. 335 the key goal of the use of such methods is to reduce the overall cost associated to the discovery and development of a new drug by identifying the most promising candidates to focus the experimental efforts on. a number of books and reviews on the impact of computational chemistry for lead structure determination highlight these efforts. [336] [337] [338] [339] in general, in silico methods can be divided into (i) ligand-based approaches, which rely on known active compounds. based on their physicochemical properties crucial for biological affinity, activities are predicted by extrapolation on not-yet tested substances, e.g. machine learning techniques and classical quantitative structure-activity relationship (qsar). ligand-based approaches are invaluable tools in cases where no structural information about the pharmacological targets is available. (ii) on the other hand, structurebased approaches use experimentally determined 3d structures of the targets, such as molecular docking or structure-based pharmacophore modeling for virtual screening. these methods allow for gaining insight into protein-ligand interactions at an experimentally determined (static) level (however not considering flexibility). a unique platform containing 3d coordinates of experimentally solved protein structures (by x-ray crystallography or nmr) is the protein data bank (pdb) currently comprising more than 50,000 structures of biomolecules and protein-ligand complexes. 340 additionally, there are several pdb-related web services and tools, which enable to use the pdb-portal in a rich diversity of information services for students and scientists. 341 particularly in the early stage of drug development, such as lead discovery and lead optimization, computational approaches allow for a target-oriented and rationalized proceeding, and thus may substantially help to maximize the success rate. 338 a recently published review on the impact of computer-assisted approaches in antiviral research thoroughly describes underlying in silico techniques, and highlights the benefits of computational approaches for the discovery of antiviral lead structures. 342 in anti-hrv research the capsid protein and the protease 3c revealed to be promising targets (as described before). inhibitors are assumed to have a major impact for the treatment of hrv-infections. additionally, these targets are structurally elucidated, and some potent ligands are known as well. these facts enable the performance of sensible computer-assisted approaches, both ligand-and structure-based. some studies using an in silico approach for the discovery of potential anti-hrv agents focusing on the mentioned targets will be reported in the following paragraphs. for compounds acting as potential hrv-capsid binders, some classical qsar and 3d qsar studies have been performed. while in classical qsar, the relationship between 2d calculated properties derived from chemical structures and measured biological activities are explored statistically, 3d qsar techniques are aimed at deriving a correlation and in turn activity prediction based on spatial arrangements of chemical properties and atoms. applying the 3d qsar technique comfa (comparative molecular field analysis) statistical models are derived, which are visualized in color-coded contours around the molecule. therein spots indicate where electrostatic properties and spatial arrangements are favorable for biological activity. 343 in the studies of diana et al., artico et al., and verma et al., qsar techniques helped on one hand to analyze and rationalize the structural features of active compounds essential for the interaction to the hrv canyon's binding pocket, and on the other hand to search for new classes of capsid binders, thus to narrow the synthetic challenges for specific anti-hrv agents, respectively. [344] [345] [346] [347] [348] in all these investigations hydrophobicity was found to be one of the most important determinants of substance activity. qsar combined with simplex representation of molecular structure was applied by kuz'min et al. based on the selectivity index (cc 50 /ic 50 ) and the hrv-2 inhibitory concentration of a set of [(biphenyloxy)propyl]isoxazole derivatives. 188 on the basis of qsar analysis and computational design, three new isoxazoles with high activity prediction were selected and synthesized. they all revealed a strong coincidence between experimental and predicted anti-hrv activity and selectivity index. terminal benzene substituents with negative electrostatic potential and a molecule length of approximately 5.5-5.6 å have been suggested as mandatory features within this chemical class for a hrv-2 inhibitory activity. hrv-serotypes show a high level of conservation at the protease 3c binding site; sequence alignment and secondary structure predictions suggested an overall architecture and mechanism of hrv-3c proteases that correlates with cellular cystein-and serine proteases, such as chymotrypsin and trypsin. 349, 350 the identity among 3c proteases from different families is however modest and provides space for the development of specific inhibitors for hrv-3c protease. 350 in a recently published review on selective inhibitors of picornavirus replication, de palma et al. summarized all currently known chemical structures acting as peptidic or nonpeptidic inhibitors of this viral target. 156 in 2000, reich et al., used the hrv 3c protease co-crystal structure information to rationalize the target-oriented synthesis of hrv 3c protease inhibitors from the class of substituted benzamides. activity data and subsequent crystallographic studies pointed out important requirements for the inhibition of the 3c protease. 351 similarly, maugeri et al. used a structure-based approach, and performed docking studies based on the 3c protease crystal structure with a virtual library consisting of benzamide derivatives. quantum-mechanic calculation proposed substituents with most promising biological activities. this workflow guided the design and synthesis of substances virtually assumed to act as substrate analogues. synthesis of some of these compounds and biological testing confirmed the underlying hypothesis. 219 quantitative molecular modeling studies were performed to better define and predict interactions between bicyclic 2-pyridone derivatives that showed to be irreversible inhibitors of the 3c protease. in these studies molecular mechanics simulations to evaluate chemical rate of covalent bond formation and free energy calculation combined with crystallographic studies were applied to explain the differences in activity of some irreversible peptidomimetic inhibitors. these data were used as a basis for further optimization of these compounds. 224, 352 in a recent study performed by kuo et al. some 6,800 compounds were subjected to a high troughput screening in the search for novel inhibitors for both 3c and 3cl proteases from picornavirus and coronavirus, respectively. 217 five nonpeptides were identified with ic 50 values r10 mm against severe acute respiratory syndrome-coronavirus 3cl-protease; one molecule was found to additionally inhibit the 3c proteases of coxsackievirus, enterovirus, and rhinovirus. this compound (id 43146) contains a dihydropyrazole ring decorated with two phenyl groups and a lengthy n-butyl-benzimidazolylamino-toluene. it was used as starting point for the selection of further four analogs showing ic 50 values in the range of 0.5-10 mm against the tested viral proteases. by means of docking-based computer modeling, the authors tried to rationalize the binding discrepancies responsible for individual and common protease inhibitors, thus to provide a rational base for the development of nonpeptide multiple-function inhibitors against coronaviruses and piciornaviruses. in anti-hrv research, first application scenarios have been conducted using pharmacophore models. according to the official iupac definition by wermuth et al., 353 a pharmacophore describes the 3d arrangement of steric and electronic features necessary to trigger or block a biological response. pharmacophores can be represented by three-dimensional chemical features, which include hydrogen bond donors and acceptors, aromatic rings, hydrophobic groups, as well as positive and negative ionisable moieties. additionally, the shape of ligands can be represented by shape features, which essentially describe the van der waals radii of the ligand atoms. the pharmacophore concept has proven to be successful, not only in rationalizing structure-activity relationships but also by its large impact in developing appropriate 3d-tools for efficient virtual screening. 336, 354 steindl et al. elaborated ligand-and structure-based pharmacophore models implementing the essential feature of the covalent binding to the cysteine 147 in the active site of the hrv-2 3c protease. thus, the in silico approach focused on defining a new pharmacophore feature representing a target structure for nucleophilic addition in the ligands, which is a crucial step for protease inactivation. the generated hypotheses retrieved known 3c protease inhibitors in the virtual screening cycle, and proposed potential (unconfirmed) ligands of the 3d protease binding site from available databases. 355 the viral capsid of several hrvs has been elucidated by crystallization and resolution of the 3d-structure. the hrv coat protein complexed with its highly active inhibitor win 61209 was used as starting point for the generation of structure-based pharmacophore models by . the models were used for virtual screening of a large commercially available 3d database. for final selection of virtual hits worth to be subjected to biological testing, docking studies and principal component analysis were performed. six candidates were tested for their ability to inhibit hrv serotype 39 by multiple-cycle cpe inhibition assay. although all of them showed a certain antiviral potential, one longitudinal piperazine derivative inhibited the virus at a concentration below 10 mm. some of the test candidates showed difficulties in the interpretation of experimental results due to their relatively high cytotoxicity and bad solubility. this circumstance asks for more cautious estimation of molecular properties for compound selection as stated by the authors. 356 in a subsequently performed study, the best validated pharmacophore model was used for the identification of naturally derived hrv coat protein inhibitors. 144 for virtual screening experiments the in-house generated 3d-database dios was used (as described before). based on the virtually predicted ligands and considering knowledge from traditional use, sesquiterpene umbelliferons from the gum resin of ferula sp., i.e. asafetida, were finally selected as most promising candidates. for biological evaluation, the antiviral activities of asafetida and its isolated constituents were assessed by an exploratory determination of the inhibition of the cpe induced by hrv serotypes 1a, 2, 14, and 16. the results revealed a dose-dependent and selective anti-hrv activity against serotype 2 for asafetida and its virtually predicted constituents, farnesiferols b and c ( fig. 5 ; table iii ; ic 50 : 2.6 and 2.5 mm, respectively). to scrutinize the selectivity of these two compounds against hrv-2 in comparison to the other tested serotypes, the amino acid sequences of hrv-2 and hrv-16 vp1 were aligned. since all amino acid residues involved in ligand binding showed 100% match in both serotypes, the experimentally determined selectivity profile could not be explained by different binding pockets. the serotype alignment does however not reflect potential protein flexibility during binding, which might differ between the hrv serotypes. additionally, off-target effects could be a reason for the observed selectivity. in a recently performed virtual parallel screening approach, we tried to identify potential targets of human pathological relevance for 16 constituents isolated and identified from the medicinal plant ruta graveolens. 318 using the screening platform pipline pilot 357 included in discovery studio, 358 low-energy conformers of the 16 identified molecules from r. graveolens were subjected to parallel screening. for this purpose, the inte:ligand pharmacophore model collection was used. 359 it currently comprises 2.208 models covering 280 unique pharmacological targets. based on the predicted ligand-target interactions, the authors focused on three biological targets, namely acetylcholinesterase, the hrv coat protein, and the cannabinoid receptor type 2. virtual hits and nonhits were assayed on their respective targets for a critical evaluation of the performed target-fishing approach. beside other predicted bioactivities, determination of their cpes on hrv-2 revealed the virtual hit arborinine ( fig. 5 ; table iii; ic 50 : 3.2 mm) and the nonpredicted hit 6,7,8-trimethoxycoumarin ( fig. 5 ; table iii ; ic 50 : 12.9 mm) as the most active anti-hrv constituents. it could be shown that the applied in silico strategy has the capacity of catalyzing drug discovery profoundly for all those diseases where molecular targets or molecular ligands are well defined to create reliable pharmacophore models. hrv, a prominent member of the picornaviridae family, infects humans more frequently than any other virus. infections with hrv mainly lead to upper respiratory diseases, such as the common cold, but may also cause more severe lower respiratory tract disorders. although the symptomology and severity of the common cold is relatively mild and the course of disease self-limiting, the socio-economic impact is tremendous in terms of recouping lost productivity due to sick leave. in the last decades, a number of anti-hrv agents from different origin-synthetics, natural compounds, biologicals, botanicals, and nutritionals-have been discovered. different concepts have been used as strategy for their discovery either starting from a phenomenological effect, e.g. empirical knowledge from folk medicine, or from a targetbased molecular level, e.g. icams, capsid binders, and hrv protease inhibitors. some of the outcomes revealed potent and promising activities that partly have been evaluated for the management of hrv-induced common colds in clinical trials mainly with sobering benefit. since the hrv infection is not life-threatening in most cases, a potential therapy has to be safe and effective with an almost unrecognizable level of side effects. these preconditions render the search for anti-hrv-agents into a high challenging endeavor and explains why no antiviral agent is approved for the prevention or treatment of hrv-infection until today, despite the significant efforts. moreover, the high variability of rhinoviruses suggests the need of more than one active principle covering different modes of action for an effective treatment. therefore, there is a high need for an ongoing search for new synthetic as well as natural compounds on a molecular level. the increasing knowledge about the hrv life cycle, gene, and protein sequence combined with the improved technologies in the field of experimental and computational methods have continuously enabled further insights into the spectacular world of hrv. only with this fundamental research, virtual screening approaches, such as qsar, pharmacophore-and docking-based screening cycles, or computational compound design, are applicable on a rational base. with the gained expertise from different disciplines and an adequate infrastructure for further research, it is encouraging to hope that discovery and clinical development efforts will continue in the search for agents that may treat or prevent the annoying common cold. picornavirales, a 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serotype 2 (hrv2) human rhinovirus 3 at 3.0 a resolution the canyon hypothesis viral cell recognition and entry crystallographic and cryo em analysis of virion-receptor interactions a cell adhesion molecule, icam-1, is the major surface receptor for rhinoviruses the minor receptor group of human rhinovirus (hrv) includes hrv23 and hrv25, but the presence of a lysine in the vp1 hi loop is not sufficient for receptor binding members of the low density lipoprotein receptor family mediate cell entry of a minor-group common cold virus multiple receptors involved in human rhinovirus attachment to live cells structural studies of two rhinovirus serotypes complexed with fragments of their cellular receptor the cellular receptor to human rhinovirus 2 binds around the 5-fold axis and not in the canyon: a structural view the major and minor group receptor families contain all but one human rhinovirus serotype human rhinovirus type 54 infection via heparan sulfate is less efficient and strictly dependent on low endosomal ph human rhinovirus type 89 variants use heparan sulfate proteoglycan for cell attachment internalization of human rhinovirus 14 into hela and icam-1-transfected bhk cells viral evolution toward change in receptor usage: adaptation of a major group human rhinovirus to grow in icam-1-negative cells rhinovirus-mediated endosomal release of transfection complexes major and minor receptor group human rhinoviruses penetrate from endosomes by different mechanisms cryoelectron microscopy analysis of the structural changes associated with human rhinovirus type 14 uncoating formation of rhinovirus-soluble icam-1 complexes and conformational changes in the virion conformational changes, plasma membrane penetration, and infection by human rhinovirus type 2: role of receptors and low ph uncoating of human rhinovirus serotype 2 from late endosomes x-ray structure of a minor group human rhinovirus bound to a fragment of its cellular receptor protein the expression and purification of human rhinovirus protease 3c polypeptide 2a of human rhinovirus type 2: identification as a protease and characterization by mutational analysis the eif4g-eif4e complex is the target for direct cleavage by the rhinovirus 2a proteinase purification of two picornaviral 2a proteinases: interaction with eif-4 gamma and influence on in vitro translation 2a proteinases of coxsackie-and rhinovirus cleave peptides derived from eif-4 gamma via a common recognition motif conservation of amino acids in human rhinovirus 3c protease correlates with broad-spectrum antiviral activity of rupintrivir, a novel human rhinovirus 3c protease inhibitor fields virology rhinovirus infects primary human airway fibroblasts and induces a neutrophil chemokine and a permeability factor basal cells of differentiated bronchial epithelium are more susceptible to rhinovirus infection resistance of differentiated human airway epithelium to infection by rhinovirus effect of isoflavans and isoflavenes on rhinovirus 1b and its replication in hela cells enantiomeric effects of homologues of disoxaril on the inhibitory activity against human rhinovirus-14 in vitro activity of win 51711, a new broad-spectrum antipicornavirus drug two groups of rhinoviruses revealed by a panel of antiviral compounds present sequence divergence and differential pathogenicity an orally bioavailable oxime ether capsid binder with potent activity against human rhinovirus in vitro activity of expanded-spectrum pyridazinyl oxime ethers related to pirodavir: novel capsid-binding inhibitors with potent antipicornavirus activity novel [(biphenyloxy)propyl]-isoxazole derivatives for inhibition of human rhinovirus 2 and coxsackievirus b3 replication structure-based virtual screening for the discovery of natural inhibitors for human rhinovirus coat protein in vitro resistance study of rupintrivir, a novel inhibitor of human rhinovirus 3c protease establishment of a mouse model for human rhinovirus infection human rhinovirus 1b exposure induces phosphatidylinositol 3-kinase-dependent airway inflammation in mice mouse models of rhinovirus-induced disease and exacerbation of allergic airway inflammation prophylactic activity of intranasal enviroxime against experimentally induced rhinovirus type 39 infection intranasal interferon-alpha 2 treatment of experimental rhinoviral colds topical enviroxime against rhinovirus infection therapeutic activity of enviroxime against rhinovirus infection in volunteers efficacy of oral win 54954 for prophylaxis of experimental rhinovirus infection ineffectiveness of echinacea for prevention of experimental rhinovirus colds current status of anti-picornavirus therapies selective inhibitors of picornavirus replication inhibitors of 3c cysteine proteinases from picornaviridae isolation of a monoclonal antibody that blocks attachment of the major group of human rhinoviruses an antibody fragment from a phage display library competes for ligand binding to the low density lipoprotein receptor family and inhibits rhinovirus infection modification of experimental rhinovirus colds by receptor blockade viral receptor blockage by multivalent recombinant antibody fusion proteins: inhibiting human rhinovirus (hrv) infection with cfy196 comparative antirhinoviral activities of soluble intercellular adhesion molecule-1 (sicam-1) and chimeric icam-1/immunoglobulin a molecule a soluble form of intercellular adhesion molecule-1 inhibits rhinovirus infection spectrum of activity of soluble intercellular adhesion molecule-1 against rhinovirus reference strains and field isolates soluble ldl minireceptors. minimal structure requirements for recognition of minor group human rhinovirus neutralization of a common cold virus by concatemers of the third ligand binding module of the vldl-receptor strongly depends on the number of modules rhinovirus-stabilizing activity of artificial vldl-receptor variants defines a new mechanism for virus neutralization by soluble receptors in vitro studies of the antirhinovirus activity of soluble intercellular adhesion molecule-1 mechanisms of receptor-mediated rhinovirus neutralization defined by two soluble forms of icam-1 efficient neutralization and disruption of rhinovirus by chimeric icam-1/immunoglobulin molecules recombinant soluble low density lipoprotein receptor fragment inhibits minor group rhinovirus infection in vitro prevention of rhinovirus infection in chimpanzees by soluble intercellular adhesion molecule-1 efficacy of tremacamra, a soluble intercellular adhesion molecule 1, for experimental rhinovirus infection: a randomized clinical trial inhibitors of picornavirus replication the structure of antiviral agents that inhibit uncoating when complexed with viral capsids structural and virological studies of the stages of virus replication that are affected by antirhinovirus compounds structural analysis of antiviral agents that interact with the capsid of human rhinoviruses conformational change in the floor of the human rhinovirus canyon blocks adsorption to hela cell receptors the site of attachment in human rhinovirus 14 for antiviral agents that inhibit uncoating a comparison of the anti-rhinoviral drug binding pocket in hrv14 and hrv1a analysis of three structurally related antiviral compounds in complex with human rhinovirus 16 antiviral capsid-binding compounds can inhibit the adsorption of minor receptor rhinoviruses in vitro activity of pleconaril and ag7088 against selected serotypes and clinical isolates of human rhinoviruses activity of pleconaril against enteroviruses susceptibility of coxsackievirus b3 laboratory strains and clinical isolates to the capsid function inhibitor pleconaril: antiviral studies with virus chimeras demonstrate the crucial role of amino acid 1092 in treatment in vitro activity of r 61837, a new antirhinovirus compound in vitro activity of pirodavir (r 77975), a substituted phenoxy-pyridazinamine with broad-spectrum antipicornaviral activity quantitative structure-activity relationship studies of [(biphenyloxy)-propyl]isoxazole derivatives. inhibitors of human rhinovirus 2 replication sch 48973: a potent, broad-spectrum, antienterovirus compound antipicornavirus activity of sch 47802 and analogs: in vitro and in vivo studies sch 38057: a picornavirus capsid-binding molecule with antiviral activity after the initial stage of viral uncoating direct and specific inactivation of rhinovirus by chalcone ro 09-0410 comparative studies on the antirhinovirus activity and the mode of action of the rhinovirus capsid-binding agents, chalcone amides 4 0 ,6-dichloroflavan (bw683c), a new anti-rhinovirus compound 3,4-dihydro-2-phenyl-2h-pyrano[2,3-b]pyridines with potent antirhinovirus activity antipicornavirus activity of substituted phenoxybenzenes and phenoxypyridines activity of 2-(3,4-dichlorophenoxy)-5-nitrobenzonitrile (mdl-860) against picornaviruses in vitro application of crystallography to the design of antiviral agents clinical activity of pleconaril in an experimentally induced coxsackievirus a21 respiratory infection oral pleconaril treatment of picornavirus-associated viral respiratory illness in adults: efficacy and tolerability in phase ii clinical trials efficacy and safety of oral pleconaril for treatment of colds due to picornaviruses in adults: results of 2 double-blind, randomized, placebo-controlled trials relationship of pleconaril susceptibility and clinical outcomes in treatment of common colds caused by rhinoviruses the effect of oral pleconaril on hepatic cytochrome p450 3a activity in healthy adults using intravenous midazolam as a probe safety and efficacy of intranasal pirodavir (r77975) in experimental rhinovirus infection inhibition of polyprotein processing and rna replication of human rhinovirus by pyrrolidine dithiocarbamate involves metal ions nitric oxide inhibits dystrophin proteolysis by coxsackieviral protease 2a through s-nitrosylation: a protective mechanism against enteroviral cardiomyopathy an antiviral mechanism of nitric oxide: inhibition of a viral protease nitric oxide inhibition of coxsackievirus replication in vitro nitric oxide donors inhibit the coxsackievirus b3 proteinases 2a and 3c in vitro, virus production in cells, and signs of myocarditis in virus-infected mice effect of nitric oxide on rhinovirus replication and virus-induced interleukin-8 elaboration inhibition of proteolytic activity of poliovirus and rhinovirus 2a proteinases by elastase-specific inhibitors an antiviral peptide inhibitor that is active against picornavirus 2a proteinases but not cellular caspases antiviral activity of caspase inhibitors: effect on picornaviral 2a proteinase dual inhibition of human rhinovirus 2a and 3c proteases by homophthalimides structure of human rhinovirus 3c protease reveals a trypsin-like polypeptide fold, rna-binding site, and means for cleaving precursor polyprotein individual and common inhibitors of coronavirus and picornavirus main proteases structure-assisted design of mechanism-based irreversible inhibitors of human rhinovirus 3c protease with potent antiviral activity against multiple rhinovirus serotypes new anti-viral drugs for the treatment of the common cold structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 1. michael acceptor structure-activity studies structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 2. peptide structure-activity studies structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 6. structure-activity studies of orally bioavailable, 2-pyridone-containing peptidomimetics structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 3. structure-activity studies of ketomethylene-containing peptidomimetics structurebased design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 8. pharmacological optimization of orally bioavailable 2-pyridone-containing peptidomimetics structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 4. incorporation of p1 lactam moieties as l-glutamine replacements in vitro antiviral activity of ag7088, a potent inhibitor of human rhinovirus 3c protease inhibition of human rhinovirus-induced cytokine production by ag7088, a human rhinovirus 3c protease inhibitor pharmacokinetics and safety of an antirhinoviral agent, ruprintrivir, in healthy volunteers phase ii, randomized, double-blind, placebo-controlled studies of ruprintrivir nasal spray 2-percent suspension for prevention and treatment of experimentally induced rhinovirus colds in healthy volunteers in vitro antiviral activity and single-dose pharmacokinetics in humans of a novel, orally bioavailable inhibitor of human rhinovirus 3c protease gaining target access for deoxyribozymes a morpholino oligomer targeting highly conserved internal ribosome entry site sequence is able to inhibit multiple species of picornavirus small interfering rna molecules as potential anti-human rhinovirus agents: in vitro potency, specificity, and mechanism mode of action of 2-furylmercury chloride, an antirhinovirus compound methoxyflavones as potent inhibitors of viral-induced block of cell synthesis antiviral effects of pyrrolidine dithiocarbamate on human rhinoviruses broad-spectrum antiviral and cytocidal activity of cyclopentenylcytosine, a carbocyclic nucleoside targeted at ctp synthetase in vitro antiviral activity of ribavirin against picornaviruses another ten stories in antiviral drug discovery (part c): ''old'' and ''new'' antivirals, strategies, and perspectives the broadspectrum antiviral ribonucleoside ribavirin is an rna virus mutagen ribavirin: recent insights into antiviral mechanisms of action inhibition of rhinovirus replication in in organ culture by a potential antiviral drug synthesis of syn and anti isomers of 6-[[(hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1h-benzimidaz ol-2-amine. inhibitors of rhinovirus multiplication comparative studies on the modes of action of the antirhinovirus agents ro 09-0410, ro 09-0179, rmi-15,731, 4 0 ,6-dichloroflavan, and enviroxime the antiviral compound enviroxime targets the 3a coding region of rhinovirus and poliovirus sequence determinants of 3a-mediated resistance to enviroxime in rhinoviruses and enteroviruses evidence that enviroxime targets multiple components of the rhinovirus 14 replication complex controlled trial of enviroxime against natural rhinovirus infections in a community the activity of enviroxime against rhinovirus infection in man activity against rhinoviruses, toxicity, and delivery in aerosol of enviroxime in liposomes 2-amino-3-substituted-6-[(e)-1-phenyl-2-(n-methylcarbamoyl)vinyl]imid azo[1,2-a]pyridines as a novel class of inhibitors of human rhinovirus: stereospecific synthesis and antiviral activity short synthesis and anti-rhinoviral activity of imidazo[1,2-a]pyridines: the effect of acyl groups at 3-position synthesis, antiviral activity, and biological properties of vinylacetylene analogs of enviroxime synthesis and antiviral activity of c2 analogs of enviroxime: an exploration of the role of critical functionality sensitivity of rhinoviruses to human leukocyte and fibroblast interferons cell and virus sensitivity studies with recombinant human alpha interferons comparative susceptibility of respiratory viruses to recombinant interferons-alpha 2b and -beta intranasal interferon-alpha 2 for prevention of natural rhinovirus colds intranasal interferon alpha 2 for prevention of rhinovirus infection and illness interferon-beta ser as prophylaxis against experimental rhinovirus infection in volunteers an effective dosage regimen for prophylaxis against rhinovirus infection by intranasal administration of huifn-alpha 2 efficacy and tolerance of intranasally applied recombinant leukocyte a interferon in normal volunteers intranasally applied recombinant leukocyte a interferon in normal volunteers. ii. determination of minimal effective and tolerable dose recombinant human interferon-gamma as prophylaxis against rhinovirus colds in volunteers ineffectiveness of postexposure prophylaxis of rhinovirus infection with low-dose intranasal alpha 2b interferon in families a randomized controlled trial of glucocorticoid prophylaxis against experimental rhinovirus infection synergism between anti-rhinovirus antivirals: various human interferons and a number of synthetic compounds failure to demonstrate synergy between interferon-alpha and a synthetic antiviral, enviroxime, in rhinovirus infections in volunteers property distributions: differences between drugs, natural products, and molecules from combinatorial chemistry a new rapid and effective chemistry space filter in recognizing a druglike database rational selection of structurally diverse natural product scaffolds with favorable adme properties for drug discovery natural products as sources of new drugs over the last 25 years ethnomedicinal antivirals: scope and opportunity plant substances as antiviral agents: an update plant substances as antiviral agents host defense function of the airway epithelium in health and disease: clinical background herb sales down 6 percent in mainstream market echinacea for preventing and treating the common cold echinacea for preventing and treating the common cold. the cochrane database of systematic reviews evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis echinacea in the prevention of induced rhinovirus colds: a meta-analysis the role of alkamides as an active principle of echinacea alkylamides from echinacea are a new class of cannabinomimetics: cannabinoid type 2 receptordependent and -independent immunomodulatory effects synergistic anti-oxidative effects of alkamides, caffeic acid derivatives, and polysaccharide fractions from echinacea purpurea on in vitro oxidation of human low-density lipoproteins echinacea extracts modulate the pattern of chemokine and cytokine secretion in rhinovirus-infected and uninfected epithelial cells modulation of immune response gene expression by echinacea extracts: results of a gene array analysis preventing the common cold with a garlic supplement: a double-blind, placebocontrolled survey in vitro virucidal effects of allium sativum (garlic) extract and compounds enhancement of in vitro human immune function by allium sativum l. (garlic) fractions efficacy of cold-fx in the prevention of respiratory symptoms in community-dwelling adults: a randomized, doubleblinded, placebo controlled trial efficacy of an extract of north american ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial safety and tolerability of north american ginseng extract in the treatment of pediatric upper respiratory tract infection: a phase ii randomized, controlled trial of 2 dosing schedules inhibitory effect of ginsenoside rg3 and its derivative ginsenoside rg3-2h on no production and lymphocyte proliferation effect of cvt-e002 (cold-fx) versus a ginsenoside extract on systemic and gut-associated immune function inhibitory effect of ginseng polysaccharides on rotavirus infection antiviral activity of dammarane saponins against herpes simplex virus i effect of a traditional japanese herbal medicine, hochu-ekki-to (bu-zhong-yi-qi tang), on immunity in elderly persons effects of five kampohozais on the mitogenic activity of lipopolysaccharide, concanavalin a, phorbol myristate acetate and phytohemagglutinin in vivo immunological restoration and anti-tumor effect by japanese herbal medicine in aged mice antiinflammatory effects of bu-zhong-yi-qi-tang in patients with perennial allergic rhinitis hochu-ekki-to inhibits rhinovirus infection in human tracheal epithelial cells efficacy of a pelargonium sidoides preparation in patients with the common cold: a randomized, double blind, placebo-controlled clinical trial kern winfried v. pelargonium sidoides extract for acute respiratory tract infections traditionally used pelargonium species: chemistry and biological activity of umckaloabo extracts and their constituents aqueous ethanolic extract of the roots of pelargonium sidoides-new scientific evidence for an old anti-infective phytopharmaceutical efficacy of an aqueous pelargonium sidoides extract against herpesvirus protective effect of a natural carrageenan on genital herpes simplex virus infection in mice polysaccharides as antiviral agents: antiviral activity of carrageenan iota-carrageenan is a potent inhibitor of rhinovirus infection recommendations for reporting randomized controlled trials of herbal interventions: explanation and elaboration ethnobotany and the search for new drugs: ciba foundation symposium 185 ethnobotany and natural products: the search for new molecules, new treatments of old diseases or a better understanding of indigenous cultures? how scientific is the science in ethnopharmacology? historical perspectives and epistemological problems pedanius dioscorides of anazarbus-de materia medica sesquiterpene coumarins from ferula assafoetida l antiviral flavonoid from pterocaulon sphacelatum, an australian aboriginal medicine in silico target fishing for rationalized ligand discovery exemplified on constituents of ruta graveolens l antiviral activity of natural occurring flavonoids in vitro antiviral agents from higher plants and example of structure-activity relationship of 3-methoxyflavones 0 -hydroxy-3-methoxyflavones with potent antipicornavirus activity biodiversity: a continuing source of novel drug leads structure and stereochemistry of thysanone: a novel human rhinovirus 3c-protease inhibitor from thysanophora penicilloides discovery, total synthesis, hrv 3c-protease inhibitory activity, and structure-activity relationships of 2-methoxystypandrone and its analogues antiviral activity of raoulic acid from raoulia australis against picornaviruses antipicornavirus flavone ro 09-0179 cinnamoyl-and hydroxycinnamoyl amides of glaucine and their antioxidative and antiviral activities antiviral activity of flavones and flavans present status and prospects of flavonoids as antiviral agents inhibition of an early stage of rhinovirus replication by dichloroflavan (bw683c) effect of dichloroflavan (bw683c) on the stability and uncoating of rhinovirus type 1b failure of intranasally administered 4 0 , 6-dichloroflavan to protect against rhinovirus infection in man failure of oral 4 0 ,6-dichloroflavan to protect against rhinovirus infection in man neural networks as data mining tools in drug design chemoinformatics and drug discovery methods and principles in medicinal chemistry the impact of informatics and computational chemistry on synthesis and screening enhancing drug discovery through in silico screening: strategies to increase true positives retrieval rates neural networks for chemists the protein data bank the protein data bank (pdb), its related services and software tools as key components for in silico guided drug discovery development of antiviral agents using molecular modeling and virtual screening techniques comparative molecular field analysis (comfa). 1. effect of shape on binding of steroids to carrier proteins investigation on qsar and binding mode of a new class of human rhinovirus-14 inhibitors by comfa and docking experiments synthesis and structure-activity studies of some disubstituted phenylisoxazoles against human picornavirus comfa analysis of the interactions of antipicornavirus compounds in the binding pocket of human rhinovirus-14 dihydro-2-oxazolyl)phenoxy]alkyl]-3-methylisoxazoles: inhibitors of picornavirus uncoating understanding human rhinovirus infections in terms of qsar site-directed mutagenesis suggests close functional relationship between a human rhinovirus 3c cysteine protease and cellular trypsin-like serine proteases the picornaviral 3c proteinases: cysteine nucleophiles in serine proteinase folds substituted benzamide inhibitors of human rhinovirus 3c protease: structure-based design, synthesis, and biological evaluation structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3c protease inhibitors. 6. structure-activity studies of orally bioavailable, 2-pyridone-containing peptidomimetics glossary of terms used in medicinal chemistry (iupac recommendations 1997) methods and principles in medicinal chemistry human rhinovirus 3c protease: generation of pharmacophore models for peptidic and nonpeptidic inhibitors and their application in virtual screening docking versus pharmacophore model generation: a comparison of highthroughput virtual screening strategies for the search of human rhinovirus coat protein inhibitors ca: accelrys. 358. discovery studio rollinger extended her studies to the fields of phytochemistry, ethnopharmacology, molecular modelling and its application in natural product science completing the habilitation thesis entitled ''the search for bioactive natural products rollinger is a project leader and an associate in various national projects, as well as executive guest editor for current pharmaceutical design. she has been awarded the phoenix science award (2005) and received several additional awards until 1994 she was a postdoctoral research fellow at the institute of immunology, university marburg, where she studied picornavirusimmune cell interactions and the virus-induced cytokine induction. thereafter, she was a postdoctoral fellow at the institute of virology and antiviral therapy key: cord-324335-eoabmyg7 authors: nicoletti, marcello title: new solutions using natural products date: 2020-08-21 journal: insect-borne diseases in the 21st century doi: 10.1016/b978-0-12-818706-7.00007-3 sha: doc_id: 324335 cord_uid: eoabmyg7 most antibiotics are derived from natural products, like penicillin, as well as recent insecticides, like pyrethroids. secondary metabolites are produced by plants as ecological chemical mediators, and can therefore possess intrinsic physiological properties against other organisms. these benefits are far from being fully explored. in particular, attention is here focused on the multipurpose neem tree (azadirachta indica), reporting several experiments of applications in the field of seed oil and neem cake. the latter product seems to be promising because of the low cost, the possible production on a large scale, and the selection of effects in favor of beneficial organisms. neem cake is able to act on different sites, as required by integrated pest management. several utilizations of neem products are reported and their potentiality evidenced. some considerations in this chapter may appear distant from the title of the book, but only by applying the general natural rules can the reason of the single phenomenon be understood. other studies on resistance mechanisms of plasmodium are enabling new possible methods of control always based on natural products activity. and biotic targets, which are important to the individual homeostasis and survival. one form of evidence in accordance with this interpretation is the strong correlation between natural products' producers and biodiversity, therefore indicating a matter of adaptation. however, it is possible to argue that if differences can characterize each organism from another, the some is not true in case of a molecule. once determined the structure, a molecule is a molecule, even if generated by the metabolism or by a synthetic route, and therefore the living rules cannot be applied to the molecular world. this is true only in part. we must consider, in particular for natural products, the conformational forms, which are different ways of the same molecule to react. an organic molecule can change easily its 3d structure adapting to the environmental needs, like we open and close our hands. furthermore, once inside the metabolism, the molecule, even if inorganic, is integrated in the organic network and it is forced to collaborate to an integrated living system. the cell environment is far different from the test tube of the chemist. in practice, the molecule is simply part of an advanced complex integrated dynamic system, limiting its freedom. beside the consideration that physical forces work in the same way in the assembling matter, as we can know and distinguish a giraffe from a wizard, we can study natural compounds and distinguish them on basis of the structures and assign their place and role. about the role, we must remember that natural products are chemical mediators inside the environment, meaning that they must act on the receptor of the target organisms. therefore, the structures of natural products are derived from their activity, the same argument we use in the consideration of a pharmacological drug. here, the importance of natural products inspiring all the molecules tailored to affect living organisms. in particular, among the detected activities in plant species, the defensive against herbivorous is highly reported. plants cannot counteract by movements like animals and therefore an arsenal of chemical weapons is essential in their fight for survival. therefore, it is highly possible to find natural products toxic or repellent to phytophagous, like insects, as well as active constituents against pathogens. natural products with such properties should be extracted and found in the complex and confused reservoir of secondary metabolites, but the presence into the plant is not sufficient. it is necessary to realize the mechanism of action and the potentiality to be used as marketed products. therefore, the pathway should comprehend the discovery, the isolation, the sources, the bioactivities, and the possibility to be obtained in high quantity, the method of utilization, the environmental impact and the cost of production. the natural products have been already reported for antibiotic activity. in particular, essential oils and phenols are stated in many papers as being responsible of antibacterial and insecticide properties (ghosh et al., 2012; gibbons, 2008) . however, the activity seems to be too general. most essential oils are composed of the same main constituents, the difference being mainly quantitative for each compound or hidden deeply inside the plethora of secondary constituents. furthermore, excluding the phenols typical of essential oils, the quantity of known phenols is very large and complicated, with thousands of structures reported and different activities connected. therefore, special research must be performed, including the possibility to test new substances never reported. among secondary natural products with insecticide activity, a special place must be assigned to essential oils. in this regard, several papers report the utilization of essential oils as the active ingredient against pests. the antimicrobial activity of essential oils is also well-reported and evident in nature. several plants accumulate essential oils in the inner parts of roots and rhizomes, in order to avoid the devastating attack of micropathogens, wherein the plant often accumulates precious reserve substances. in other cases, the aerial parts are focused on defensive or cooperative actions. some birds defend their clutch by surrounding the nest with aromatic plants. the human utilization of essential oils of different kinds against insects has a long story. herodotus reported the use in ancient egypt of mosquito nets and towers impregnated with fish odor to avoid mosquito bites. an essential oil is a complex chemical mixture of substances volatile at ordinary temperature (figs. 7.1 and 7.2), and therefore the constituents must have low molecular weight. in other words, they are micromolecules, with average molecular weight of 120-160 uma and hydrocarbon prevalence. essential oils can be extracted from the raw materials by utilizing their volatile properties, such as in the steam distillation method. the antimicrobial activity of essential oils is usually a consequence of the content of phenols, but other properties must be considered. on the basis of the structures of the active constituents, there are two types of essential oils. the first one, mainly present in less advanced angiosperm dicotyledons, like magnolidae, contains mainly root and fruit drugs rich in simple phenolic phenylpropanoids, which are mainly utilized by the plant in protection of pathogens. in rosidae and sympetalae, the terpenoids progressively become predominant. the new volatile constituents, in addition to the protective and toxic effects, afford a positive attraction on pollinatory agents, evidencing the plant position and allowing a memory of the selected species. in this way, the scenario of the interaction between animals and plants changes from defensive to collaborative. the new plants to be selected and appreciated can enrich the offer to the collaborative animals fig. 7 .1 a typical current apparatus for the production of essential oils by steam distillation. with fruits of inebriant flavors, colored flowers and other nice experiences. therefore, utilized essential oils are mainly complex mixtures of volatile plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes, which means lipid secondary metabolites, and, to a lesser extent, of aromatic compounds. the choice of essential oil depends firstly on the taxonomy of the selected plant and the effects depend on the nature of the constituents of the essential oil. the conclusion, based also on direct experiments, is the presence of a general antibiotic and insecticide activity; however, another real need is a selective toxicity in favor of the useful organisms. therefore, some kind of activity is expected for an essential oil, but there is a necessity to maximize its effectiveness. they are exploited in several fields, such as perfumery, food, pharmaceutics, and cosmetics, but essential oils have also long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. essential oils, currently more than 300 of which are known, are highly variable in their complex composition. usually, at least a mixture of more than main 30 different constituents of low molecular weight is present. among the single species, the qualitative composition of the essential oil is respected, although a quantitative variability is common between population according to the environmental pressures. however, some terpenes can be easily found, like the hydrocarbons (myrcene, pinene, terpinene, limonene, cymene, αand β-phellandrene) and the oxygenated ones, like the alcohols (geraniol, linalool, menthol, terpineol, borneol) , the aldehydes (citral, citronellal), ketones (menthone, pulegone, carvone), bicyclic monoterpene ketones (thujone, verbenone, fenchone), acids (citronellic acid, cinnamic acid), oxides (1,8-cineole) and esters (linalyl acetate), but the aromatic phenols (carvacrol, thymol, safrole, eugenol) are also common. a few essential oils may also contain sulfur-containing constituents, methyl anthranilate, coumarins, and special sesquiterpenes such as zingiberene, curcumin, farnesol, sesquiphellandrene, turmerone, nerolidol, etc. often these components are at low concentrations (less than 1% each), but the opposite is also possible, with major compounds that can represent up to 70% of the total volume of oil, as much as 90% like eucalyptol in eucalyptus or limonene in citrus or pinenes in turpentine of pinus. therefore, the antiparasitic activity of an essential oil can vary according to differences in its chemical composition, but it is usually present. nowadays, there is an increasing interest in the utilization of essential oils against endoparasites and ectoparasites of animals and humans, in particular when they are resistant to conventional drugs. however, the use of essential oils is in general restricted for the high cost and considering that usually they are not adequately specified for the considered target (bagavan and rahuman, 2010; shaalan et al., 2005; tikar et al., 2018) . again, also in the case of essential oils, the insurgence of the insecticide resistance must be considered (brown, 1986) , although usually less common in these cases. therefore, in consideration of their general but also weaker effectiveness of essential oils in comparison with synthetic insecticides, their utilization requires the insecticidal properties of essential oils to be investigated in different approaches of selection of the studied plants and their uses. some examples of researches, in which i had occasion to participate, involving essential oils in insect-borne diseases are reported here. the leading idea was to utilize the essential oil properties in an innovative way, such as in mixture or selected types. in 2017 (benelli et al., 2017a,b) , the activities of five essential oils were investigated. the essential oils were obtained from different plants: pinus nigra var. italica (pinaceae), hyssopus officinalis subsp. aristatus (lamiaceae), satureja montana subsp. montana (lamiaceae), aloysia citriodora (verbenaceae), and pelargonium graveolens (geraniaceae) against culex quinquefasciatus (diptera: culicidae), which is a vector of lymphatic filariasis and of dangerous arboviral diseases, such as west nile and st. louis encephalitis. the research was original in its focus on the potential synergistic and antagonistic effects, testing them in binary mixtures on c. quinquefasciatus larvae. mixtures of essential oils are very easy to obtain, since the constituents are perfectly soluble in the final solution and the selected oils were cheap and easy to find on the market. in such a way, knowing the composition, it is possible to combine constituents, enhancing the range and the quality of activity. the pool of the investigated species was highly varied, but this was considered a positive factor. first, the chemical composition of each essential oil was investigated by gc-ms analysis, which is the best analytic method in such mixtures of volatile compounds. therefore, it was also necessary to test the activity of each essential oil and later to try the best combination on the basis of its effectiveness. the highest effectiveness was obtained by s. montana subsp. montana essential oil (lc 50 ¼25.6 μl l à1 ), followed by p. nigra var. italica (lc 50 ¼49.8 μl l à1 ), and a. citriodora (lc 50 ¼65.6 μl l à1 ). it was possible to obtain an enhancement of the larvicidal activity by preparing simple binary mixtures of essential oils (ratio 1:1), such as s. montana+a. citriodora, which showed higher larvicidal toxicity (lc 50 ¼18.3 μl l à1 ). on the other hand, testing s. montana + p. nigra (1:1), an antagonistic effect was detected, leading to an lc 50 (72.5 μl l à1 ) higher than the lc 50 values calculated for the two oils tested separately. therefore, these results indicate the extreme need for innovation and imagination in natural products research, against many papers repeating the same procedure that change only the plant used. another work (pavela et al., 2016a,b) was based on geographic distribution and the traditional use. six medicinal and aromatic plants-azadirachta indica (see later in this chapter), aframomum melegueta, aframomum daniellii, clausena anisata, dichrostachys cinerea, and echinops giganteus-have been traditionally used in cameroon to treat several disorders, including infections and parasitic diseases. the aim was to evaluate the activity of the essential oils of these plants against trypanosma brucei tc221 and determine their selectivity with balb/3t3 (mouse embryonic fibroblast cell line) cells as a reference. essential oils from a. indica, a. daniellii, and e. giganteus proved to be the most active ones, with half maximal inhibitory concentration (ic 50 ) values of 15.21, 7.65, and 10.50 μg/ml, respectively. these essential oils were characterized by different chemical compounds, including monoterpenes and sesquiterpene hydrocarbons and oxygenated sesquiterpenes. some of their main components were assayed as well on t. brucei tc221, and their effects were linked to those of essential oils. in this way, the research partially confirmed the ethnopharmacological indications, validating their traditional use and confirming the utility of popular information in the search for useful plants. the synergic action of binary mixtures of similar constituents of essential oils against larvae of the filariasis vector culex quinquefasciatus was also the inspiration behind research (benelli et al., 2017a,b) on four apiaceae species: trachyspermum ammi, smyrnium olusatrum, pimpinella anisum, and helosciadium nodiflorum. initially, all the essential oils proved to be highly toxic to the larvae, but short-term exposure to both binary mixtures strongly reduced emergence rates, fertility, and natality of the c. quinquefasciatus that survived after the treatment at the larval stage. in addition, larvicidal acute toxicity of essential oils main constituents, i.e., germacrone, isofuranodiene, and (e)-anethole, were carried out, with lc 50 being 18.6 mg l à1 , 33.7 mg l à1 , and 24.8 μl l à1 . the results demonstrated the promise of these essential oils and their constituents to develop cheap and effective mosquito larvicides. in another paper (pavela et al., 2016b) published in the same year, the vector target was the same but the selection of the plant totally different, as endemic to madagascar. the reason is that in some parts of the world, there are interesting examples of endemic flora whose species could contain different essential oils and therefore different activity. for this reason, pharmaceutical companies often explore remote parts of amazonia or isolated zones in search of new active compounds. there were examples of exploitation of rare african rauwolfia species to obtain their indole alkaloids. working with endemic species is important considering that in many cases, populations are in limited numbers and at risk of extinction, and we need to identify their molecular treasure before they disappear. this was also the motivation for my trips to several parts of the world, focusing in particular on deserts and islands, in search of special plants. madagascar's fauna and flora are diverse and unique. when the unique gondwana continent braked up in several pieces, india started to move to asia living africa. however, a consistent block remained near to africa, becoming a great island, now known as madagascar. this happened more than 100 million years ago. the isolation of madagascar gave rise to a particular case of biodiversity. this is the story of the beginning of madagascar, as far as we know. here, it is important to report that the island is characterized by at least seven very different habitats, each with different endemisms. the potentiality of cinnamosma madagascariensis, an endemic species widely present in the forests of madagascar, was reported to us thanks to the exceptional collaboration with professor philippe rasoanaivo, who had a deep knowledge of the flora of the island and their economic importance. this plant has important traditional uses ranging from management of dementia, epilepsy, and headache to malaria (rakotosaona et al., 2015) . few data have been reported about the chemical composition of its essential oils, and no studies have been published on its bioactivity against mosquitoes. once again, we first investigated the chemical composition of essential oils extracted from stem bark and leaves of the plant, and later their larvicidal potential against the filariasis vector culex quinquefasciatus. the reason was that when you have little information, you must consider that different parts of a plant can contain very different essential oils. in fact, gc-ms analysis revealed differences between the volatile profiles of leaves and bark oils. in the former, linalool (30.1%), limonene (12.0%), myrcene (8.9%), and α-pinene (8.4%) were the major constituents, while in the latter one, β-pinene (33.3%), α-pinene (19.3%), and limonene (12.0%) were the most representative compounds. acute toxicity experiments conducted on larvae of the filariasis vector c. quinquefasciatus led to an lc 50 of 61.6 and 80.1 μl l à1 for the bark and leaf essential oils, respectively. overall, cinnamosma madagascariensis bark and leaf essential oils against filariasis vectors proved to be promising, since they are effective at moderate doses. the insecticidal activity of the essential oil of another malagasy plant was also studied (benelli et al., 2020) . hazomalania voyronii is popularly known as hazomalana and its use to repel mosquitoes and resist against insect attacks has been handed down from generation to generation in madagascar. the property of the essential oils obtained from the stem wood, fresh and dry bark of h. voyronii were able to repel important mosquito vectors (aedes aegypti and culex quinquefasciatus). furthermore, the toxicity of the aforementioned essential oils was investigated by who on three insect species of agricultural and public health importance (cx. quinquefasciatus, musca domestica, and spodoptera littoralis), respectively, as well as the adequate topical application methods and compared with the commercial repellent n,n-diethyl-m-toluamide (deet). repellence assay revealed almost complete protection (>80%) from both mosquito species for 30 min when pure fresh bark essential oil was applied on the volunteers' arms, while deet 10% repelled more than 80% of the mosquitoes up to 120 min from application. the research validated the traditional use of the bark essential oil to repel insects, although an extended-release formulation based on h. voyronii essential oils is needed to increase the repellent effect over time. furthermore, it evidenced the wide spectrum of insecticidal plants potentially useful in the fabrication of green repellents and insecticides useful to control mosquito vectors and agricultural pests, avoiding the utilization of synthetic products. another interesting study (benelli et al., 2017b) was dedicated to helichrysum faradifani (asteraceae), which is a perennial endemic shrub growing in rocky and sandy places of madagascar. the ethnopharmacological about malagasy traditional medicine reports that this plant is used as a wound-healing agent, disinfectant, and for the treatment of syphilis, diarrhea, cough, and headache. the chemical composition of the essential oil distilled from the aerial parts of h. faradifani, and analyzed by gc-ms, evidenced that monoterpene hydrocarbons (51.6%) were the major fraction of the essential oil, with bicyclic α-fenchene (35.6%) being the predominant component. sesquiterpene hydrocarbons (34.0%) were the second major group characterizing the oil, with γ-curcumene (17.7%) being the most abundant component. its insecticidal activity was evaluated against second, third, and fourth instar larvae of the lymphatic filariasis vector culex quinquefasciatus by acute toxicity assays. the most sensitive were second instar (lc 50 ¼85.7 μl l à1 ) larvae. for the third and fourth instar larvae, the estimated lc 50 were 156.8 and 134.1 μl l à1 , respectively. finally, a different approach to volatile substances was performed, considering that smoke is often traditionally used against mosquitos (ansari and razdan, 1996) . therefore, the larvicidal, pupicidal, and smoke toxicity of senna occidentalis and ocimum basilicum leaf extracts against the malaria vector anopheles stephensi were evaluated (murugan et al., 2015) . in larvicidal and pupicidal experiments, s. occidentalis lc 50 ranged from 31.05 (i instar larvae) to 75.15 ppm (pupae), and o. basilicum lc 50 ranged from 29.69 (i instar larvae) to 69 ppm (pupae). smoke toxicity experiments conducted against adults showed that s. occidentalis and o. basilicum coils evoked mortality rates comparable to the pyrethrin-based positive control (38%, 52%, and 42%, respectively). furthermore, the antiplasmodial activity of these plant extracts in antiplasmodial assays was evaluated against chloroquine (cq)-resistant (cq-r) and cq-sensitive (cq-s) strains of plasmodium falciparum. the s. occidentalis 50% inhibitory concentrations (ic 50 ) were 48.80 μg ml à1 (cq-s) and 54.28 μg ml à1 (cq-r), while those for o. basilicum ic 50 were 68.14 μg ml à1 (cq-s) and 67.27 μg ml à1 (cq-r). the high potentiality of the reported data must be considered. these smokes, as the essential oils, can be quite easily obtained in good quantity and low cost and therefore locally produced and directly utilized. this is important for countries with limited economic resources. the distribution of individuals in accordance with the boltzmann curve is the result of the current chemical-physical environmental pressure, concentrating the organisms of the species in the most adapted form. however, sooner or later situations are destined to change, and some of the individuals confined in the wings of the curve are ready to profit of the change and enter in the center, as soon as the conditions will be favorable to them. another consequence of this typical statistical distribution is the careful preservation of individual types inside the population. in practice, on the genetic point of view, the best species or the favored community do not exist in absolute, and any declaration or pseudo-scientific argumentation about the primacy of a race, also human, must be considered as a guilty stretch. as confirmation, this is also in accordance with the distribution of the constituents of matter at a subatomic level. the final consideration is that the chemical composition of a plant is limited, being the expression of the genome of the species, but it may change at any time in response to internal and external stimuli. let us use these concepts to evaluate insecticides used in insect-borne diseases. the interest in the use of biocidal products of natural origin began in the 1930s and grew until the 1950s, when it was obscured by the arrival of synthetic insecticides on the scene. for a long time, the pesticides scenario was dominated by synthetic products, until several factors caused a decline in their utilization. however, in the last 20 years, interest in natural products has reappeared intensely, especially for the control of noxious insects at larval stage. this situation has matured, as is well known, following the indiscriminate (and not always necessary) use of excessive amounts of pesticides which, once released into the environment, are difficult to eliminate, as evidenced by the paradigmatic case of ddt (see chapter 1). at the same time, incidence of insect resistance has increased, resulting in partial product inactivity and/or increasingly massive dosage requirements. all this led to a need for the formulation of a new generation of pesticides, and to focus research and production efforts on natural products. in 1997, the world health assembly reported in resolution 50.13, section 2.4, the need to develop bio-insecticides. slowly but inexorably, the pesticides market registered the rise of biopesticides from natural products. the change in favor of natural products is the result of two concomitant facts: the evidence of the environmental damage due to massive utilization of synthetic products, and a new and growing sensibility in favor of respect for habitats, asking for more compatible solutions. in the current search for the production of a new generation of pesticides, useful for mankind's battle against superbugs and other threats, to face challenges to food supply and health, plant sources play a relevant role. the current prevalence of natural products evidences that a consistent number of biocides and antibiotics have been obtained from substances produced by living organisms, which are part of the great book of mother nature, whose lessons are still useful. that probably means that attention in chemistry is finally moving from the free synthetic approach to natural products, already selected during the long story of molecular evolution. in an article that appeared in acs' journal of natural products, charles l. cantrell and colleagues pointed out the impact of natural productssubstances produced by living plants, animals, and other organisms-on the production of pesticides. the article reports the percentages for registered insecticides obtained from 277 new active ingredients in the period 1997-2010 (cantrel et al., 2012) . the paper's aim was focused on the impact of natural product and natural product-based pesticides on the u.s. market, obtained on the basis of nai registrations of new active ingredient registrations with the u.s. environmental protection agency (epa). the ingredients are categorized into four categories: biological (b), natural product (np), synthetic (s), and synthetic natural derived (snd). in particular, nps are considered substances produced by living plants, animals, and other organisms. the report evidences that nps, snds, and bs all have origins in natural product research. nps accounted for 35.7%, ss for 30.7%, bs for 27.4%, and snds for 6.1%, arising from the combination of conventional pesticides and biopesticides. in the registered conventional pesticides, the category of biopesticides alone registered an evident majority of nps (with 54.8%), followed by bs (44.6%), snds (0.6%), and ss (0%). in contrast, on the conventional pesticides alone, the category s clearly dominated with 78%, followed by snd with 14.7%, np 6.4%, and b 0.9%. the review indicates that in the same period, more natural products were registered as nais for conventional pesticides and biopesticides than any other type of ingredient. the authors report that when biological ingredients and natural products recreated in laboratories are included, more than 69% of all nais registered in that time frame have natural origins. more than two out of every three new insecticides approved in the last years are directly derived from natural substances produced in plants or animals or have significant roots in them. it is noteworthy that these numbers are very similar to those obtained if we compare with a similar projection concerning registered medical drugs in a similar period, and published in the same scientific journal. it is also noteworthy that a similar trend can be observed in the case of the registration of medical drugs in the period 1981-2014, as previously reported in the same scientific journal by david j. newman and gordon m. cragg (newman and cragg, 2016): 36% of registered drugs directly or indirectly derived from np of secondary metabolism, 16% from b, 11% from snd, and only 31% from s. again, the details reveal differences in the sectors, with np and b dominating in anticancer and antibiotics, whereas the opposite concerns antiinflammatories, with s clearly dominating. these data, obtained on a total number of 1562 new approved drugs, are the results of several reviews that confirmed these percentages. in particular, the authors stress the role of microbes in the production of new drugs derived from natural products: "we wish to draw the attention of readers to the rapidly evolving recognition that a significant number of natural product drugs/leads are actually produced by microbes and/or microbial interactions with the "host from whence it was isolated," and therefore "it is considered that this area of natural product research should be expanded significantly." in other words, the future of pharmaceutical drugs could be related to natural products obtained by natural synthesis. once conceivable that the shift from synthetic pesticides to biopesticides seems to be incontrovertible, as fueled by the resistance phenomenon and the general tendency for "natural," the key argument is the choice of the raw material for the best bioinsecticide. as evident from the above reviews, bioinsecticides could be extracted from a living organism, like a plant, or produced by a living organism, like a bacterial strain by hemisynthesis, or obtained by synthesis in accordance with the structure of the active natural product. here, the debate is open between those affirming that "a molecule is a molecule" and those in favor of "original" natural products. anyway, in the case of an extract, the complexity of ingredients cannot be reproduced or performed by synthesis. the main characters of a natural "ideal" insecticide should be: biodegradability, environmental care, sustainability (obtained from renewable materials) and selectively (harmful to beneficial insects). it should also satisfy some conditions to be economic appealing and relevant, like be easy to produce, low cost, derived from raw materials that available and abundant in the country where the insecticide should be utilized. the last conditions are important to avoid accumulation by multinational agencies, as is happening for coffee and cacao. finally, but not in order of importance, the ideal natural insecticide must be able to compete in the market with the insecticides currently in use. the research for the ideal bioinsecticide is open, starting from the plant to be used. evident that this role should be assigned to neem. at that time, the tree was practically unknown in the occident, since its distribution and utilization were confined to the indian subcontinent. therefore, i wrote an article about neem to explain the importance of this plant, and some years later, i was contacted by an italian industry using neem oil because of the curiosity and interest raised by that article. the references about this plant and its use appear since time immemorial, as reported in the ayurveda and unani systems of traditional medicines, and even in the earliest sanskrit writings referring to the medical uses of fruits, seeds, oil, leaves, roots, and bark (gupta, 2001) . neem can be found all over the indian subcontinent since the time of the sanskrit-speaking aryans. so important was the species for the aryans, they even mentioned and included it in their sacred ayurveda, which is the sacred book of indian medicine. the species was later dispersed throughout the old tropics, including indonesia, either naturally or brought back by the ancient austronesian sailors after visiting and trading in india at least around 2000 years ago. through the centuries (kumar and navaratnam, 2000) , the medical importance of neem never waned in the indian subcontinent and it is now considered the "village pharmacy" for its importance in the ordinary life of indians, who use this plant to treat several illnesses (nix, 2007; girish and bhat, 2008) . many other news and references increased my interest. the marvelous tree, the problem-solving tree, the divine tree, india's tree of life, nature's drugstore, the pharmacy tree, the panacea for all diseasesthese are just some of the terms used to evidence the respect for this plant and its importance (ruskin, 1992; brahmachari, 2004; puri, 1999; national research council, 1992) . neem's relevance and its beneficial properties has been reported by the who/unep (1989), which considered neem as an effective source of environmentally powerful natural pesticide and one of the most promising trees of the 21st century for its great potential in pest management, environmental protection, and medicine koul and wahab, 2007) . furthermore, the u.s. national academy of sciences dedicated a report to neem, significantly titled "neem-a tree for solving global problems" (nas, 1992) . the importance of neem has increased exponentially in recent years. considering the enormous quantity of results and scientific data concerning the validation of medicinal and biological properties, the international scientific community included neem on the list of the top 10 plants to investigate and use for the sustainable development of the planet and the health of mankind (tewari, 1992; foster and moser, 2000) . however, in the occident, insecticidal activity is the most common application for neem oil and its derived products. the plant, besides neem, is also known as nimba, nimtree, margosa, and indian lilac. in botany, neem is azadirachta indica a. juss and belongs to the meliaceae family. meliaceae are angiosperm rosidae, closely related to simaroubaceae and rutaceae (schumutterer, 2002) . the family includes 51 genera and c.600 species. these are woody plants, like trees, shrubs, and shrublets, pantropically present, with a few temperate representatives in china and south africa. it is estimated that c.39 million years ago, two subfamilies diverged, cedreloideae with 14 genera and melioideae with 37 genera, including aglaia, dominating with c.120 species, and azadirachta with only two species. meliaceae are commonly known as the mahogany family, being known mainly for some important timber species, such as the true mahogany (swietenia mahagony). however, losses due to overexploitation and genetic erosion, as well as toxic effects on workers, limited the use of this true mahogany, nowadays widely replaced by spanish mahogany (s. macrophylla). azadirachta indica is an evergreen tree that grows up to a height of 15-20 m, but in favorable conditions it can to a height of about 20-35 m, with a trunk diameter up to 2.5 m (fig. 7.3) . the leaves of neem, composed of 9-19 leaflets, meaning 4-8 leaflets with a single terminal, are abundant, suspended by a strong and long petiole which lacks stipules, crowded near the ends of the branches. the leaflets are toothed, deeply serrated, their margins irregularly serrated, sharply pointed, and curved like a scythe. young leaves are pale, tender green, and tinted with rust, but during the favorable season the tree profits from the fresh, green color and shining surface of the leaves, giving a delicate and charming appearance. white small flowers are abundant, very fragrant, bisexual, or staminate in male exemplars. they are arranged in clusters at the axils of the leaves. they present five separated petals arranged in the form of a star. they appear in spring, and open in the afternoon giving out a delicate smell, which increases during the night. the fruit is a smooth, yellow-green, small, round drupe with a sweetflavored pulp. during the monsoon, when the flowers have fallen and the tree is in full foliage, the curved, toothed leaves, massed round the branches, have a distinctive appearance, which is easy to recognize. from march to may, the flowers, with five whitish petals, appear in great numbers on long, drooping stems. flowers are used to produce a bitter honey. the fleshy fruits are purplish-black, single-seeded drupes, which turn yellowish when ripe. elliptical in shape, they have a sweet-tasting juice loved by birds and bees. however, after the rains, the fruits change, giving off a strong unpleasant smell. in autumn, fruits fall down in great quantities if not harvested. the tree is believed to be native at least of north-east india and burma, or indonesia, but now widely distributed in the indian subcontinent, and it grows naturally throughout the dry regions of the country. it is usually planted along roads and avenues in towns and villages, because it grows fast and easily, and has an irregularly rounded crown with a canopy of leaves, making it a useful shade tree ( fig. 7.4) . the central regions of india are considered the patria of neem. if you go to coimbatore, in tamil nadu, you can find neem trees everywhere, in towns and in the countryside. it is mainly used for shade, lining streets or in most people's back yards. in india, it grows throughout the states of uttar pradesh, bihar, west bengal, orissa, delhi, maharashtra, gujarat, and andhra pradesh, but the original natural distribution is obscured by widespread cultivation. cultivation is easy, since neem usually grown from seed but can be propagated also from cuttings or root suckers, and it is a fast-growing species. potential utilizations of neem concern human, animal, and environmental health. the last one is a recent but very important acquisition. neem is cultivated for two main reasons: environmental care and the production of seed neem oil. the tree's tolerance and adaptation to hot and dry climates has made it one of the most commonly planted species in arid and semi-arid areas (tiwari et al., 2014) . the survival capacity of neem is mainly due to its highly expanded root system. neem trees are extremely useful to counteract desertification and furnish the only source of wood in arid and nutrient-deficient zones. the plant does not need particular care and grows rapidly up to 30 m tall. neem trees attain maturity in 6-7 years in areas where the sunlight is intense, weather is warm, and good well-drained soil is found. the tree is stable in windy zones and can live for 200 years or more. to survive in arid climates, neem depends on a wide strong root system with a deep tap root and extensive lateral roots, which are ideal for soil conservation. furthermore, its planetary presence can contribute to positive carbon sequestration to minimize climate changes, considering that adult neem trees can retain ae2.2 g of co 2 per m 2 and per hour, which means 40-50 tons of co 2 per hectare. therefore, neem trees can be considered to be air purifiers as well as air fresheners. for all these reasons, neem is widely cultivated in warm countries, and its areal distribution is expanding rapidly by massive cultivations in sub-tropical regions of america (caribbean cuba, central and southern america), asia (nepal, pakistan, bangladesh, sri lanka, myanmar, thailand, malaysia, indonesia, iran, china, turkey, indonesia), africa (kenya, cameroon), and australia. the cultivation of neem trees is in particular increasing in the drought-prone areas, like in south arabia (arafat valley) and in the uae. in 1978, northern nigeria, thanks to the governmental project arid zone afforestation (azap), saw 700,000 neem trees being planted. in europe, some cultivations are reported only in southern spain and portugal (sara and folorunso, 2002) . the presumed current global neem trees presence and production are reported in table 7 .1. the data were obtained by cross-referencing several sources and are only indicative, considering that a real census was never completed in many countries (in particular in china) and many plantations are in progress. india is still by far the homeland of neem, but the scenario has changed rapidly in the last years and will continue to do so in the future, as can be deduced from the data in table 7 .1. visiting oman, i noted the presence of planted neem trees in areas where acacia was the only other woody plant (usually the only plant) able to survive. the neem tree is resistant to drought and it grows in many different types of soil, but it thrives best in well-drained deep and sandy soils. normally, it flourishes in areas wherein the neem is a life-giving tree, especially for dry coastal, southern districts. its capacity to survive in arid zones improved cultivation in sub-arid to sub-humid conditions, with annual rainfalls between 400 and 1200 mm. it can tolerate high to very high temperatures, but it does not tolerate temperatures below 4°c, making cultivation in temperate climate very difficult. however, the future worldwide distribution of neem is not predictable. indians are convinced that it will be difficult to obtain similar ideal conditions to their country and others in the orient; however, the story of the cultivation of cinchona by dutch botanists in indonesia tells us that the results of the cultivation can be successful and the results even superior. in the complete linnaean binomial name of neem we found a. juss, which is the mark of the author of this species, designating the scientist who first published the name and a complete and scientifically reliable description of the species. a. juss refers to antoine laurent de jussieu (1748-1836), a great french botanist, who was the first to publish a complete and valid natural classification of flowering plants, named genera plantarum, published in 1789, the same year as the french revolution, surpassing the sexual system presented by linneus. antoine laurent jussieu was the member of a family of a plant enthusiasts; his uncle was the botanist bernard de jussieu, whose transferred knowledge and unpublished work were the starting point of the book of antoine laurent, and his son andrien-henri also became a botanist. the merit of his work was the use of multiple characters to define taxa. in this approach, he achieved a significant improvement over the "artificial" system of linneus, mainly based on the number of the reproductive characters, i.e., stamens and pistils. many people know the work and name of linnaeus, but the impact of jussieu's work was fundamental in taxonomy, founding the principles that served as the foundation of plant classification in a natural system. many presentday plant families are still attributed to him, as the species is to linnaeus. that's what who can find in ordinary sources of information. the consequent idea is that jussieu, though living in france at a historical revolutionary time, was totally dedicated to botany, but his work was also revolutionary, through a strange pathway. deeper information about his life is a source of important lessons. his uncle, bernard de jussieu, invited the young antoine to paris, where he was trained in medicine for 4 years. however, his uncle, via his position as a demonstrator at the jardin du roi (royal garden), had other plans for antoine. he guided his nephew's studies and prepared him for a lecturer's position at the garden, which was soon to become vacant. at just 22-years old, antoine was transferred to that position and his botanical training was limited because the subject then was viewed only as an accessory to his medical course. the inexperienced jussieu had to study botanical topics by night, since he had to teach by day. using the plants in the garden to teach plant morphology, which were arranged according to the current artificial system of joseph pitton de tournefort, jussieu started to realize the inadequacy of that system. this progressively changed his interest into a true passion for botany, and classification began until, as part of an application for a place at the academy of sciences, he produced a treatment of the ranunculaceae, starting a complete revision of the plant taxonomy system. continuing in his study, it became apparent to jussieu that the artificial system of tournefort was inadequate, and from 1774 he began arranging the plants in the royal garden in his own way and finally transferring the knowledge in the construction of his own system of plant classification. despite the initial success obtained by linnaeus' sexual system, it was clear to jussieu that the swedish naturalist had used a counting method, whereas it was necessary to grade the characters, considering some of them more important than others, depending on how variable they are within a species. this was a necessary lesson to consider the variability of living organisms correctly. however, he continued practicing medicine, chiefly devoting himself to the health of very poor people. in 1790, he was put in charge of the hospitals and charities of paris. in the final years of his life, jussieu, by then almost blind as well as deaf, dedicated the last part of his extraordinary life to meditation and prayer. the neem tree has few diseases and enemies (boa, 1995; schmutterer, 1998) . in general, it is considered a very resistant and healthy plant . however, it is possible that after its spread around the world, something is changing. we must move our focus from india to the new settlements, in africa. in northern nigeria, neem now is planted in towns and villages, as a highly evaluated source of shade and firewood, as well in the establishment of shelterbelts. in nigeria, like in other parts of africa, the small twigs of neem are used to clean and whiten teeth, in consideration of its antibacterial properties. in particular, reports of pests and damages comes from east africa, like gall mites (phyllocoptes sp.) on older plants, but the most potentially dangerous pest is aonidiella orientalis, known as oriental scale (ofek et al., 1998; lale, 1998; elder et al., 1998) . this insect was widespread in western kenya but is not currently harmful. likely to be native to asia, it has been introduced to many regions via shipments of plants and then began its slow spread. some ports check for this and other scales in plant shipments. in africa, neem has been widely planted in the sahel region. oriental scale first appeared in the sahel during the mid-1970s and caused widespread damage to neem trees planted there. infestations were first detected in nigeria in 1987 along its border with cameroon and by the mid-1990s, widespread damage had been reported to neem trees throughout northeastern nigeria. the oriental scale is a flattened, circular or oblong insect, about 1.6 mm in diameter. it varies in color from yellow to light reddish brown. it frequently forms large colonies and sucks the sap of small stems and branches, which is phloematic sap, rich in sugars and other organic substances. infestations often spread to the foliage, fruits, and even seeds. feeding damage causes the foliage to die, giving infested trees a burnt appearance. this is followed by progressive dieback of branches and eventual tree mortality. the heaviest infestations appear to be on large trees located either in marketplaces or around human settlements. the female attaches to the surface of a plant and causes the disease by the larvae, which roam the plant, feeding on sap by inserting their stylets, sucking sap, and weakening the plant progressively. the physical damage includes discoloration and deformation of leaves. flowers and fruits fail to develop. it is noteworthy that the effects of the pest attacks are very similar to those already reported for olive trees, including exsiccation of leaves and wood. the lesson is that, in this outbreak, we have an explosive negative mixture of alien species and man's activity on the habitat. the enormous spread of neem trees in recent years is an unusual phenomenon, whose consequences should be better monitored. before going into detail about the constituents, we must consider the typologies of the forms of the marketed products containing natural products. we are referring to insecticides, but the same considerations are simply applicable to nutraceuticals, phytomedicines, cosmetics, and even food. it is possible to find the plant drug, meaning a part of the plant utilized. the plant drug is usually utilized exsiccated, or as a derived product, like an extract, resin or oil, which can be obtained as such, or be enriched in one or more constituents, which are considered responsible for the activity. in this sequence, the original starting point, which makes the plant useful, has been betrayed in favor of increased efficacy. however, following this treatment, there are products registered as food supplements containing 90% of a pure substance and usually the origin is not at all natural (although this is not declared on the label). in such cases, the product is more similar to a medicinal drug than an extract and it should be considered and used in medicinal form. the distinction between such marketed products is not evident and not reported to the unaware consumer, who may well prefer the product due to its apparently "natural" origin. knowledge of the chemistry is therefore fundamental and the basis of any decision about the appropriate use of a plant. however, we cannot know exactly what is inside a plant. all our methods of investigation are limited and may be misleading, although papers and books are full of information about the compounds contained in plants or their derived products. this is the consequence of plants' extreme chemical complexity. in a single leaf of hemp, more than 400 constituents have been detected, considering the secondary metabolites alone, and hemp can contain high levels of thc or cannabinoids can be practically absent. in such cases, the morphology does not give any help and only a reliable chemical analysis can indicate what kind of hemp we are handling. since its beginning, phytochemistry has sought knowledge of all natural products. in about one hundred of years of activity, innumerable analyses were made and an enormous quantity of data collected in a very useful data base, but recent advancement in analytical devices and novel interpretation ask for a revision of the result of this job (kaushik et al., 2014; forin et al., 2011) . we must remember that the molecular world is not detectable by our senses and therefore we have secondhand and probably only partial information. sometimes, this information is considered sufficient to assign the compound/activity relationship, but only until other analyses confirm the presence of other molecular candidates. the seeds of neem contain at least 100 identified biologically active compounds (govindachari, 1992) . among them, major constituents are nortriterpenes, named limonoids, i.e., azadirachtin, nimbin, nimbidin, nimbolides, and many others (ragasa et al., 1997) . however, each year other new limonoids are discovered. more constituents mean more possible activities. preparations from the leaves or oils of the seeds are used as general antiseptics (mossini et al., 2009) . due to neem's antibacterial properties, it is effective in fighting most epidermal dysfunction, such as acne, psoriasis, and eczema. ancient ayurvedic practitioners believed high sugar levels in the body caused skin disease. neem's bitter quality was said to counteract this sweetness. during the last desert locust plague in africa, it was noticed that these insect, schistocerca gregaria (forskal), ate almost any vegetal around, leaving a bare landscape when they fly away, except for neem trees, probably because of the antifeedant effect of the very bitter leaves, due to the presence of limonoids. traditionally, indians bathed in neem leaves steeped in hot water. since there have been no reports of topical application of neem causing adverse side effects, this is a common procedure to cure skin ailments or allergic reactions. neem also may provide antiviral treatment for smallpox, chicken pox, and warts, especially when applied directly to the skin. its twigs are commonly used to clean and disinfect teeth. the brushing of teeth with neem to prevent gum diseases and for teeth whitening is very common, and not only in india. there are also various kinds of natural toothpaste on the market that contain neem extracts. it is also possible to prepare a homemade toothpaste to achieve shiny, cleaner teeth. neem powder is made by grinding dried neem leaves, which is traditionally used by mixing one teaspoon of neem powder with one teaspoon of baking soda and enough water to make a useful paste. these preparations can help to avoid the plaque and tartar that build up in gums, which are the root causes of bad breath. in addition to cosmetic uses, neem's antimicrobial activity to maintain dental health is also worth noting (chava et al., 2012) . a preparation can be obtained by boiling neem leaves in water until they reduce to a quarter of the original volume. finally, gargling with this concoction contributes to good breath and whiter teeth, as it kills the bacteria inside the mouth. the teas of neem leaves are utilized in indonesia and oman for their digestive properties (sujarwo et al., 2016) . neem's effectiveness is due in part to its ability to inhibit pathogens from multiplying and spreading (benelli et al., 2016) . neem produces painrelieving, antiinflammatory, and fever-reducing compounds that can aid in the healing of cuts, burns, sprains, earaches, and headaches, as well as fevers (chopra et al., 1952) . several studies of neem extracts in suppressing malaria have been conducted, all supporting its use in treatment. neem has broad applications to human and animal health, as well as organic farming (bhowmik et al., 2010) . it is reported as a powerful antiviral and antibacterial, with peculiarities that set it apart from other herbs in that class of broad antimicrobials (sandanasamy et al., 2013) . neem oil is also commonly added to a variety of creams and salves. it is effective against a broad spectrum of skin diseases including eczema, psoriasis, dry skin, wrinkles, rashes, and dandruff. these are just a few examples of the possible utilization of neem, and the potentiality of neem is considered by everybody, including the onu and other institutions, to be very high, but so far little has been done to develop appropriate products from it to help mankind. in particular, considering insect-borne diseases, in vivo activity of neem seed oil (nso) against malaria plasmodium has also been reported (dahiya et al., 2016; trapanelli et al., 2016) . today's exploding growth in human population is seriously depleting the world's natural reserves and economic resources. unless the runaway human population growth rate is slowed down, there will be little hope for raising everyone out of poverty in the developing world. besides educational constraints, the nonavailability of inexpensive methods of contraception, which do not cause trauma or impose on the esthetic, cultural, and religious sensitivities of people, limit the success of birth regulation programs. however, recent findings indicate that some neem derivatives may serve as affordable and widely available contraceptives. a recent controlled study in the indian army proved the efficacy of neem as a contraceptive. in 2020, the report of the washington-based international food policy research institute predicted a world even more unequal than the present, with food surpluses in the industrialized world and with chronic instability and food shortages in the global south, particularly in african countries. the main product of neem seed oil (nso) is the fixed oil obtained by expressing the seeds, still enclosed in the kernels. therefore, the fleshy pulp is removed or dried, to obtain the inner part. nso can be obtained by different extraction methods. most nso is produced in india by small-scale producers at ordinary temperatures using very simple machinery, which is utilized in other periods of the years for other oily extraction, like arachnids or soya seeds (figs. 7.5-7.9). however, modern apparatus is also used in india and many other countries are now producing and refining nsos. therefore, considering also the possible different geographical origin of the raw material, combined pre-and postharvesting factors can result in great differences in constituents present in marketed nsos, as already reported. therefore, despite the common definition for all the oils obtained from kernels of neem, it is necessary to consider that there is no single nso, but many nsos differing in shape, color, viscosity, chemical constitution, and activity. medicinal and cosmetic utilizations are relevant and continuously increasing. cold pressed neem oil is commercially known as margose oil and considered as pressed directly from seeds. there are hundreds of marketed products worldwide based on margose oil. neem, or margose, oil has a brown color, a bitter taste, and a garlic/sulfuric smell. the oil is usually obtained by simple pressing, but extraction by organic solvents, like hexane, is also used, though in such cases traces of the residue of solvent are always present in the final product. the type of insecticide is commonly registered as biocide, insect repellent, and antifeedant, intended for use on outdoor and greenhouse agricultural food and ornamental crops as a repellent and insect growth regulator. the products are considered to have no risk to human health because of their low toxicity via all routes of exposure. there is no reason to believe that any nontarget organisms, including honeybees and other beneficial insects, would be adversely affected, as tested by the environmental protection agency (epa). the environmental protection agency (epa) is probably the most important agency in charge of environmental care and health. it is an agency of the united states federal government whose mission is to protect human and environmental health. the epa is also in charge of the regulations of carbon emissions from power plants, automobiles, and other contributors to climate change. the epa became popular in europe because of a civil enforcement case against volkswagen and other car manufacturers, subject to reservations set forth in each of the partial settlements. in 2017, the u.s. department of justice resolved a criminal case against volkswagen ag with a plea agreement for the offenses of conspiracy, obstruction of justice, and entry of goods by false statement, and the u.s. customs and border protection resolved civil fraud claims with volkswagen arising from the illegal importation of affected vehicles. the epa was established in december 1970 by an executive order of president richard nixon, with headquarters in washington, d.c., in response to widespread public environmental concerns that gained momentum in the 1950s and 1960s. epa is a giant public agency with a budget of 9 billion us $, and it is born as reaction to the public movement in favor of the environment due to the carson's book (see chapter 1). it is considered reliable because independent. the epa is responsible for creating standards and laws to protect and preserve the natural environment and improve the health of humans by researching the effects of and mandating limits on the use of pollutants. the epa's aims include the regulation of the manufacturing, processing, distribution, and use of chemicals and other pollutants. in addition, the epa is charged with determining safe tolerance levels for chemicals and other pollutants in food, animal feed, and water. the best presentation of neem insecticide properties and the rationale of its utilization is the report of the epa about the registration of cold pressed neem oil, concerning a product named plasma neem. the report has a significant subtitle: "reasons why neem oil is an effective way to control insect hoppers" (epa (us environmental protection agency), 2012). the target of the product cold pressed neem oil is insect hoppers, because of their special liking for cash crops. the consequence is a crisis because of insect hoppers infesting these cash crops by chewing and sucking the leaves, as reported by many farmers. the reasons to use neem are focused on the effects of chemical fertilizers, which "provide a remedy but tend to kill beneficial insects as well." the report identifies three reasons why neem oil should be considered an effective way to control insect hoppers which feed on cash crops. reason 1: selectivity. "neem oil is usually sprayed on the leaves and stalks of a cash crop. so it is aimed at only the insect hoppers who spoil the cash crop by chewing the leaves or biting off bits of the stalk. the insect hopper which attacks the plant by consuming it will end up consuming the neem oil as well and hence die as an aftermath. beneficial insects, who replenish the soil in a natural fashion, do not consume the plant and hence do not get affected by neem oil." reason 2: eco-friendly efficacy. the content of azadirachtin in neem oil is considered very good at controlling and eliminating insect hoppers, avoiding the negative effects on the productivity of cash crops. furthermore, the neem oil exerts no damage to the soil or disruption of the chemical composition of a fertile soil. the product affects biological functioning of the insect hopper, and therefore the insect hopper forgets to feed or breed after devouring a cash crop with neem oil sprayed on it. the conclusion about this point is clear: "this leads to the complete elimination of the insect hopper and the infestation cycle without any other adverse chemical side effects." the action is mainly larvicide, but also deterrent and adult insecticide in most species. reason 3: cost-effectiveness. the utilization of neem oil for preserving cash crops from insect hoppers is considered very cost-effective. in comparison to chemical fertilizers, neem oil is expensive, but other positive effects must be evaluated. there is another consideration about the cost/benefit effect: eliminating negative insects and worms by neem oil, farmers need not spend money on buying supplements for the enrichment of soil. the heavy investment to preserve soil quality is totally avoided when a farmer uses neem oil. in conclusion: "overall, it can be said that neem oil as a source to control insect hoppers in cash crops is extremely beneficial for farmers." the final consideration of the epa is the advice not to use the content of the report as an endorsement of nso. in fact, it is important to remember that the report is based on scientific and experimental data. the epa is not working in favor of the industry or the market, but its judgments must be considered objective although its aim is environmental improvement. nso, obtained by the cold expression method, is the only natural productderived insecticide, whose registration was approved by epa. the epa's authority is so far internationally recognized. therefore, in the report there are three main key items of information: the evaluation of the selective insecticide activity; the preference for synthetic products in consideration of the eco-friendly properties; and the indication of azadirachtin as necessary for the activity. let us consider the report as a guide and evaluate each of these points. later, we will add other considerations. it is noteworthy that all these indications can be found already reported and present in the information about the ethnobotany and traditional medicine of neem. in the cultivation of rice, when the plantlets are underwater, the addition of extracts of neem to the usual fertilizer, not only decreases the mosquitoes number, but also has beneficial effects on the production. the utilization of neem to increase soil fertility and treat medicinally plants and livestock is recommended in the upavanavinos, an ancient sanskrit book on agriculture. the dried leaves and the oil are used as preservatives against insects and microorganisms for the postharvesting conservation of foods. conservation is guaranteed for more than a year. panels derived by the extraction of the oil are used as food additives for livestock, and the animals are washed with this diluted oil to prevent the attacks of parasites or harmful insects. in the last decade, the focus was on the potentiality of a new analytical technique, hptlc (high performance thin layer chromatography) ( fig. 7.10) . hptlc is the last evolution of planar chromatography and allows the evidence of most of the constituents of an extract in an identifying track, named fingerprint, wherein identification of constituents can be obtained by direct comparison in the same plate with the correct standards, utilizing the rf value and the reaction with adequate derivatization (nicoletti et al., 2012a,b) . improvements in separation and visualization of the spots are obtained by reduction of the size of the particles of the silica gel, constituting the fixed phase. the mobile phase can be selected on the ample repertory of solvents and their mixtures, as well as the several methods of derivatization and detection. the final effect, in comparison with ordinary planar chromatography (tlc), is like a myopic person wearing glasses. the advantages in comparison to the tlc are in the total control of the environmental conditions and the automatization of the procedures. each step of the analysis is performed entirely by a series of devices, and the operator is only asked to produce the program of actions by the software. plates can be visualized and derived in several ways, obtaining multiple information (figs. 7.11 and 7.12). they can be easily preserved and stored as digitalized images inside the computer, and immediately sent everywhere or compared with a data bank. however, the most important feature of hptlc is that the results of the analyses are very clear, thanks to careful preparation work that enabled optimal chromatographic conditions, as demonstrated by the quality of the images. in other words, our idea was to "see the molecules" (nicoletti, 2013) and obtain simple and clear evidence of the metabolic production. molecules are too small to feel their presence with our senses or directly by any sort of device, but it is possible to evidence their chemical properties in the plate, recording the rf value, the fluorescence, and the color after derivatization. an hptlc or nmr graphic needs an expert for correct interpretation, such as any specialized analysis, like a cardiogram . in hptlc, without any knowledge of chemistry, the presence or absence of a determined spot is evident (figs. 7.11 and 7.12). hptlc was selected to obtain a metabolomic approach, meaning the study of many constituents as possible, focusing on secondary metabolites (toniolo et al., 2013) . metabolomic is one of the -omic sciences generated by the dissection of the dogma of biology, based on the sequence dna➔rna➔proteins. it is necessary to propose some comments about the dogma of biology and why its crisis generated a series of other points of view. first of all, the use of the word "dogma" should be avoided in biology, since the matter is more complicated than a simple sequence, as actually happened. the central dogma of biology was first proposed in 1958 by francis crick, as a consequence of his discovery of the structure of dna. the dogma describes process by which the instructions contained in dna are converted into a functional product. another definition is: "the coded genetic information hard-wired into dna is transcribed into individual transportable cassettes, composed of messenger rna (mrna); each mrna cassette contains the program for synthesis of a particular protein (or small number of proteins)" (sources: definition from chapter 1: the dynamic cell, of molecular cell biology). the flow of genetic information within a cell follows the sequence: dna codes for rna via the process of transcription (occurring within the nucleus), rna codes for protein via the process of translation (occurring at the ribosomes), and proteins are responsible for the synthesis of the other metabolites (proteins are spread everywhere). cell data are organized within the database of dna and reversed in the metabolic flux, through rna. although clearly deficient, the central dogma of biology dominated genetics for decades, but through ongoing research, many exceptions were discovered. for example, most dna is silent, since it does not encode proteins. retroviruses, which are relevant for our arguments, present the possibility that rna transcribes into dna through the use of a special enzyme called reverse transcriptase, and other cases of deviance can be reported. however, the biggest revolution consists in the direction of the arrows. it is necessary that information could follow also the reverse pathway, allowing an appropriate response by the genome potentiality. therefore, at least the dogma must be rewritten with two-way arrows. in principle, a metabolomics study should be the determination of the pathway of cell production from the genome through transcription, but the term "metabolome" is now used to evidence the whole pool of metabolites, in particular for natural products, whereas transcriptomics is related to proteins. transcriptomics involves serious difficulty to obtain reliable results. a protein seems perfectly comfortable inside the cytoplasm, but outside, irreversible denaturation causes definitive degradation and consequent difficulty in understanding the protein's functionality. in contrast, small molecules are more stable in any environment and their molecular structures at least can be determined by phytochemical analysis (nicoletti and toniolo, 2012; toniolo et al., 2014) . however, in the metabolome we have hundreds of thousands of different constituents to be studied, and the classic approach to study the molecules one by one is impracticable, and other methods must be utilized. the lesson is that the role of any metabolite cannot be discarded a priori, and also a secondary influence in the evaluation of the property of an extract can be important to definite and obtain the final reaction. once again, the "magic bullet" paradigm is under discussion, but the total utilization of plant extracts must also be considered an unsatisfactory solution. the aim of our approach was to adapt the method to other subjects outside the pharmaceutical applications. therefore, our first studies focused on the determination of adulterants in nutraceuticals and other pharmaceutical products, like the "green viagras." later, we adapted the method and the devices to use the metabolome as a source of information about what is going on in a complex system in which living organisms are acting. therefore, we are able to study the effect of environmental factors, like ozone, on the quality of wine (valletta et al., 2015) . however, probably the most impressive application was the study of the environmental effects of the costa concordia disaster (toniolo et al., 2018) . on the night of january 13, 2012, the costa concordia, a giant yacht with approximately 1500 cabins, 3229 passengers, and 1023 crew, was wrecked off the rocks of the italian coast a few hundred meters from the port of giglio, a little island on the tyrrhenian coast in tuscany. like an injured helpless mastodon, the cruise ship inclined dangerously, until the inclination stopped with most of its starboard side under water. because of the inclination and the amount of people, the overnight evacuation of the costa concordia was a challenging process, and 32 people died. the cost of removing the ship was us$799 million. for scientists like us, interested in environmental damage, it was a unique occasion. for 1 year, 9 months, and 4 days, the enormous hull of the boat altered the underlying marine habitat, interrupting the normal flow of sunlight over a surface of more than 10,000 m 2 . the seagrass posidonia oceanica was chosen as the target organism of the impact evaluation, since, like in other parts of the mediterranean sea, it forms large underwater meadows. using hptlc analysis, it was possible to determine the health of each collected plant and make a map of the metabolic damage, which accorded with the shadowed area. however, albeit the negative conditions, the rhizomes turned out to be mostly still alive and able to reproduce the meadow again. therefore, the final task of our research was simply to wait until nature carried out its work. however, there is a further chapter of this story, written after our study. to remove the ship, a platform was transported from north europe. the problem was that the bottom of the platform was full of mytilus. when the platform was exposed to the hot mediterranean sea temperature, the mussels died, releasing their bodies, covering down the sea background and causing a further source of damage. a clear example of human stupidity and superficiality. anyway, devoted to our task, we are now repeating our analyses to understand what happened and what is still going on, relying on the quality and reliability of our indisputable results. the study of neem oil was based on the experiences obtained by improving the hptlc devices via the metabolomics approach. the central idea was to collect as much information as possible about the constituents of the neem products, without any preference for any kind of metabolite, considering any product and any extract like a unique molecular system. in the hptlc analyses on nsos, the objective was to achieve the total chemical characterization of the used oil, and then the derived products, by means of the production of a chromatographic reference profile of the metabolites' production. this objective is not easy to achieve due to the complexity and variability of neem oil. neem products are subjected to great variation in composition, due to preharvesting factors, like environmental situation, genomic differences, influences of the habitat, and others, including postharvesting situations, like harvesting and stocking, treatment of the raw material, separation of different parts, extraction methods, production of the final product, and others. in fact, analyzing different marketed neem oil from several productions and countries, we decided that it was not possible to refer to a single neem oil, but to neem oils in the plural, due the great differences in composition. therefore, we decided to obtain and adopt a reliable reference metabolomic hptlc profile for the neem extracts or products to be utilized in our biological experiments in vitro and in the field. in fact, one of the typical problems in activity tests is the differences in raw material giving rise necessarily to different results in activity and utilization. another important aspect of our metabolomic study was that the complexity of the neem profile was even greater than expected. this result is the consequence of the generalist approach. in other molecular chromatographic or spectroscopic analyses, like hplc, the result is sub judice on the detector's settlement. therefore, if the molecule does not possess the adapt chromophore, the molecule, even if it is the main component, is invisible to the detector. in hptlc, there are universal derivatization methods, like h 2 so 4 , to reveal the organic substances, but it is possible when necessary to adopt a particular agent. in this way, it was possible to exclude the presence of a relevant percentage of azadirachtins and the occurrence of other constituents relevant for the activity. this is another recurring lesson for those studying natural products. although a plant has been the object of several phytochemical studies, new constituents can be obtained. an example is the discovery of gossypol in cotton oil. insecticidal activity is reported in a hundred or so published papers, concerning a wide range of species of arthropods, as confirmations of many traditional uses (schumutterer, 1995; amirthalingam, 1998; jones et al., 1989; van der nat et al., 1991; biswas et al., 2002) . leaves are used in houses to repel and keep away insects. when half of a sample of soya leaves are sprayed with nso and offered as food to the japanese coleopteran (popillia japonica), the insects feed only on the nontreated parts of the leaves. in nicaragua, farmers spray their cultures with an aqueous extract obtained by leaving the seeds for 12 h in water. in general, nso-based products have proven to be very effective against a huge range of pests of medical and veterinary importance, mainly including mosquitoes. the insecticidal properties of neem and its many formulations are based on experimented antifeedant, fecundity suppression, ovicidal and larvicidal activities, including growth regulation and repellence against a great number (around 600) of different insects, also at very low dosages, whereas useful insects were shown to be unaffected isman, 1997; sharma et al., 1993; schumetter and singh, 1995; forin et al., 2011) . the deterrent activity was also important, which can be easily determined as reported in fig. 7 .13. other studies, like the molting and the growing of the selection under investigation, need special devices, as those reported in fig. 7 .14. in particular, a concentrated extract of neem seeds, named mitestop, developed by the university spin-off company alpha-biocare (d€ usseldorf, germany), proved to be very effective against a huge range of pests of medical and veterinary importance, including ixodes and rhipicephalus ticks, house dust mites, cockroaches (blatta, blattella, and gomphadorhina), raptor bugs (triatoma), cat fleas, bed bugs, biting and bloodsucking lice, poultry mites, and beetle larvae parasitizing the plumage of poultry. neem leaves can also be used to protect stored woolen and silk clothes from insects. concerning mosquitoes, emulsified formulations of a. indica oil showed excellent larvicidal potential against different mosquito genera, including aedes, anopheles, and culex, also under field conditions. insect growth regulatory activity of neem-borne molecules alter or block the metamorphoses of larvae (toniolo et al., 2014) . neem weakens the cuticle defense system of the young instars, causing easy penetration of pathogenic organisms, or interferes with the molting mechanism. concerning biological control, an increase of the control of aedes populations was observed after the combined application of predatory copepods and neem-based larvicidal products, since repeated application of nso does not affect populations of predatory copepods. however, relevant limitations are related to the relatively high cost of refined products and the low persistence on treated surfaces exposed to sunlight. in the soil, the half-life of azadiracthins, meaning the time necessary to degradate the compounds, is from 48 min to 4 days, depending on the environmental conditions, like moisture, high temperature, and sun. the breakdown is faster on plant leaves, due to the exposure and the surface. in the attempt to assign the active constituents of nso, we must consider that the chemistry of neem is very complicated in terms of numbers and types of constituents. despite the great quantity of dedicated research, chemical research is far from complete. hundreds of compounds have been isolated and identified from various parts of neem, with seeds being the most investigated for their commercial value. the seeds may contain approximately 45% of a brownish yellow oil, mainly constituted by several fatty acids, i.e., oleic acid cis-9-ottadecenoic (50-60%), palmitic esadecanoic acid (13%-15%), stearic acid ottadecanoic (14%-19%), linoleic acid cis, cis-9,12-ottadecadienoic (8%-16%), and arachidic acid (1%-3%), although several other compositions have been reported. after a certain time, fatty constituents tend to separate and appear as white amorphous material. the main characteristics of the oil are its unpleasant strong alliaceous odor and acrid taste, attributed to sulfurous constituents. the shape and consistence can be very different according to the extraction method and the source. in fact, the composition of neem oil is highly variable, depending on preharvesting factors, like the cultivar, the geographic and environmental origin of the raw material, collection seasons, and postharvesting, like the extraction method, preservation, and conservation. extraction can be executed with different apparatus, temperatures, pressures, and methods, affecting the yield as well as the content. as later reported, these aspects have been deeply considered and hptlc analyses can be utilized to ensure the chemical composition of the neem oil utilized in the biological experiments. among the c.300 compounds characterized from the neem seeds, more than one-third of them are nortriterpenoids, which are triterpenoids lacking some carbon atoms (kaushik et al., 2014) . nortriterpenoids are chemotaxomically well located in a few related families of rosidae angiosperm dicotyledons, i.e., rutaceae, simarubaceae, cucurbitaceae, and meliaceae, within the rutales order. generally, in the plants of the rutales order, the partial loss of the lateral chain is followed by a complicated rearranging of the remaining part, giving rise to different polycyclic molecular skeletons, full of oxygenated functional groups, partially acylated. syntheses of complex natural compounds are costly and therefore they are usually used only for special activities. it is necessary to consider this point, which is in favor of the use of the plants as source of these compounds, since the synthesis can reproduce the chirality of nortriterpenoids only with extreme difficulty and cost. nortriterpenes are a very interesting part of the plant's chemical ability, that we call biosynthesis, to produce active complex molecules. nortriterpenes present very complicated structures and high numbers of active parts. we must remember that in natural products, activity is based on the presence of functional groups, made by heteroatoms, which means mainly o and/or n. if nitrogen is present, you have alkaloids, otherwise the range is higher, comprising phenols, alcohols, ketones, and others. however, the introduction of an oxygen inside a derivative usually is obtained to increase the activity, but also introduces instability in the molecule. we must remember that a natural product started from co 2 and is likely to become co 2 again at the end of its life. this is the necessary turnover of atoms and energy in organic matter. the first process accumulates energy and it is based on reductive reactions (endothermic reactions), whereas the second one is based on oxidation and produces energy (exothermic reactions). in other words, life is based on subtraction of negative entropy from the habitat, and at the end of its life, the organism releases this energy to the system. during its life, the molecule is expected to carry out its role inside the biosystem, which is the reason for its synthesis inside the plant. to understand the role, the nature of the target is essential. in insect-borne diseases, the natural product should interfere in the life of herbivorous insects or dangerous pathogens. in the case of neem, the activity is mainly larvicidal, blocking the metamorphosis to the next pupal stage. the larvae are unable to develop and change their state. to obtain this result, a lot of chemical and finalized activity are necessary, in this case consisting of hormonal interference in the insect metamorphosis process. in other words, the molecule must be able to mimic the internal complex chemical apparatus that allows drastic changes in the forms of the insect, until it stops the process. let us consider in particular the class of nortriterpenes. we have already had occasion to meet monoterpenes in the essential oil constituents. owing to their biosynthetic origin derived from progressive accumulation of isoprene units, each made by five carbon atoms, terpenes are classified according to the increasing molecular weight in monoterpenes (c10), diterpenes (c20), triterpenes (c30), and tetraterpenes (c40). squalene, the unique precursor of all triterpenes, is a linear unsaturated hydrocarbon, but its derivatives, for stability reason, are all cyclized with hexagonal and pentagonal cycles in the final structure. among triterpenes, the most famous class is certainly the steroidal one. steroids are present in any organisms, where they carry out several fundamental roles. without steroids, starting from the cholesterol stabilization of cell membranes to the influence on metabolism, no cell, and therefore no organism, could survive. however, each organism synthetizes its own steroids. in fact, animals possess simpler steroids usually with few oxygenated functional groups, bacteria produces steroidal triterpenes mainly dedicated to the stability of the cell envelope, and plants biosynthetize quite complex structures, named phytosterols. generally, phytosterols possess more cycles respect to the ordinary structure of the steroid model and an increase of the number of functional groups (roy and saraf, 2006) . animal steroids are based on a simple, easy-to-remember sequence of four fused cycles: three hexagonal and the last pentagonal. the basic structure of a steroid is quite easy to write and remember by students, including the stereochemistry, whereas the structures of limonoids are very complex and not so easy to remember. the problem is that in the basic structure of a steroid the sequence of the cycles is linear, whereas in limonoids there are complicated re-arrangements, causing a circular total structure. the insect's molt and metamorphosis are triggered and directed by hormones, usually consisting of steroids, such as prohormones (pheromones or juvenile hormones) and ecdysones. the term "ecdysone" was introduced by the german biochemist peter karlson (1918 karlson ( -2001 in 1956 in "chemische untersuchungen € uber die metamorphosehormone der insekten" (karlson, 1956) . the etymology of this word is interesting, from the greek ekdusis "shedding," or more precisely ἐκ(ς) ("external" or "from inner to out") + δύω ("dress oneself") + -si(s) ("action") + -ona ("hormone"). however, ecdysones have typical steroidal structures, whereas limonoids are the result of a complex chemical rearrangement. thus, to interfere in insect life, special triterpenes are necessary. several plants, like those in rutales and sapindales and related families, are specialized in the synthesis of such molecules, probably made to defend the plant from phytophagous insects. to obtain this result, great chemical ability is necessary. first, part of the typical hydrocarburic lateral chain, typical of most steroids, is lost ("nor" in chemistry means exactly this passage obtained by cutting c-c bonds), and the remaining part is both oxygenated and compressed in a complicated polycyclic structure, which is quite stable in the cell environment, but easily degradable in contact with atmospheric oxygen and sunlight. in this way, the nortriterpenes can be produced in the plant and transferred to the insect with mortal effects through a subtle toxic effect. the idea is to interfere with the growth regulators, interrupting the balance of hormones, named juvenile, in particular interrupting the transition process from the larval instar stages to pupae and adults by juvenile hormone analogues. therefore, on learning this lesson from nature, we can find solutions and inspirations. on the basis of these considerations and the structural diversity ( fig. 7.15 ), nortriterpenes can be divided into two main groups: limonoids (c26), with partial loss of the lateral chain (manners, 2007) , and quassinoids (c20 and c19), with total loss of the lateral chain (vieira and braz-filho, 2006) . in ancient times, plants containing these kinds of compounds were mainly famous for the bitterness of their drugs, utilized in the production of tonics, digestifs, and medicines. limonoids are part of our ordinary experience with some fruits and are crucial for the dissemination process. when we eat a citrus fruit, such as a lemon or an orange, we taste the agreeable flavor of the juice, but the seeds are discarded because they contain the nortriterpene limonin, which is very bitter and unpleasant. by throwing away the seed, we contribute to the reproduction of the plant. several other properties of limonoids have also been reported, including antioxidant, antimicrobial, and antitumoral activities, the insecticidal of neem being so far the most important. limonoids are considered the most active ingredient of insecticide neem products. they are classified into nine basic structures, with three main skeleton types: (a) azadiracthins, highly polioxygenated and acylated, with a saturated first ring, a tetrahydrofurane ring between the two first rings, and a final dihydrofurane ring chained with the other part of the molecule; (b) nimbins, less oxygenated and acylated with a skeleton evidently similar to that of the steroids, the furane ring with only a link with the remaining part of the molecule; and (c) a third type similar to the azadirachtins one, but the polycyclic part containing the dihydrofurane ring is less complicated, giving rise to a more linear general skeleton. such variability is necessary to sustain the large range of targets. in fact, these differences are just as important for the biological activity as for the decomposition. however, in terms of market considerations, azadirachtins, in particular azadirachtin a, are considered the reference constituents to evaluate the quality, and therefore the activity, of neem oil. azadirachtin a is a highly oxygenated c-secolimonoid, whose content in the seeds is highly variable (0.1%-1%), mainly depending on the producing zone and the seasonal trend. this compound acts as a biocidal on insects after ingestion or contact, with several effects: (a) interference on the growing processes, inhibiting the molting or blocking the hormone ecdysone synthesis; (b) antifeedant, with reduction of feeding; (c) negative effects on adult fecundity and egg fertility; and (d) diminution of the defense capacity of the cuticle, easing the penetration of pathogens. in particular, the larvicidal effect consists in the formation of the "permanent larvae," i.e., larvae are able to complete the molt as a consequence of destruction of the cuticle or of hormonal perturbation of the metamorphoses. this study consists in the careful observation of the larvae transformations and in the daily count of the consequence of azadirachtins and related compounds on the molting of phytophagous with buccal apparatus, either biting-sucking and chewing, comprised in all systematic categories: orthoptera including grasshoppers, locusts and crickets, etheroptera, homoptera, aphides, cicadellidae, hymenopterous, thysanoptera, aleurodidae, dipera, beetles, and others, including acarus and nematodes. neem's oil formulations usually show a range of different azadirachtins amounts, ranging from 1000 to 4000 mg/kg, meaning that products can be obtained either by using directly poor neem oil or a dilution process of neem extracts containing different quantity of azadirachtins, up to 5%. in addition to neem oil, azadirachtins are also marketed, in particular azadirachtin a. the amount of production of this substance amounts to about 64 tons, with 80% coming from india, and china as the second producer. other data about the activities of nso and its products can be found in the references at the end of this chapter. our first experiments clearly demonstrated strong larvicidal activity of nso and neem cake on asian tiger mosquito (nicoletti et al., 2012a,b) . however, our hplc and hptlc analyses showed a low content in azadirachtins in the nso and in the methanol extract . the result was interesting, since it is well-known that insecticidal activity is strictly related to the chemical composition, but in contrast to most reports evidenced a relation between the activity and the presence of these limonoids. this consideration prompted research to identify a relationship between composition and activity in the case of nsos marketed by different producers. first, the hptlc analysis indicated great differences in the fingerprints of the analyzed oils, with special reference to limonoids (nicoletti, 2011; toniolo et al., 2014) . a second analytical step consisted of a fractionation of three selected neem oils in three fractions of increasing polarities (i.e., ethyl acetate fraction (ea), butanol fraction (bu), and water (we)). the initial neem oil and the obtained fractions were evaluated for larvicidal toxicity and field oviposition deterrence against the asian tiger mosquito, aedes albopictus. the experiments showed good toxicity of the entire neem oil and ea fractions against a. albopictus fourth instar larvae (with lc50 values ranging from 142.28 to 209.73 ppm), while little toxicity was exerted by bu and we fractions. the differences of activity were in accordance with the results of hptlc analyses, since the nsos more concentrated proved to be more active. these results were confirmed by deterrence of a. albopictus oviposition in the field (effective repellence values ranging from 98.55% to 70.10%), while no effectiveness of bu fractions was found. concerning ovideterrent activity, no difference due to the production site was found. these experimental data evidenced the possible use of neem constituents against culicidae in the field. the constituents must be found in the apolar fraction, but the hptlc analysis showed a complex composition, wherein limonoids were not prevalent. therefore, neem oil and ea fraction seem promising, since they are effective at lower doses, if compared to synthetic products currently marketed, and could be advantageous alternatives to develop newer and safer mosquito control tools, but other studies are necessary to obtain a better definition of the active constituents and tailor the neem products in accordance with the required utilization (benelli et al., 2015c; . therefore, when we started our work on neem products, we found several incongruities between the reported studies in the literature and our results . in case of incongruence of the experimental data, two main interpretations are possible. the anomalous data could be the consequence of some error in the experimental procedure or the previous reported data must be reconsidered on the light of the new ones. in fact, many scientific important discoveries have been as consequences of unexpected results. there is a strong tendency in pharmacology to assign the activity of a plant drug to one constituent, or eventually a few of the same chemical class. this is mainly a consequence of the pharmacological tests, which are tailored on the magic bullet axiom and the difficulties in determining precisely the composition of an extract. however, in an extract, and consequently in the plant, there are hundreds of compounds, with effects on bioavailability, solubility, and synergic and antagonist activity. in opposition to the magic bullet, there is the approach of the phytocomplex, invoked by many researchers in phytochemistry and pharmacognosy. an important part of research on neem was dedicated to increase its availability and properties, focusing in particular on stability and cost, toward the production of the ideal insecticide. the first aspect was assigned to the production of nanobioparticles containing neem extracts, which demonstrated clear larvicidal and deterrent activity on vectors, like ae. aldopictus, also in field conditions (chandramohan et al., 2016; murugan et al., 2016) . several factors must be considered in the case of a product based on natural substances. in theory, the plant could be available for everyone and therefore it cannot be patented. therefore, so far natural products are available for everyone and thus have been explored very little. natural products are the chemical part of the environmental interactions between living organisms and therefore they are natural candidates for the production of active drugs. the chemical production of a plant is strictly subjected to the environmental conditions that can highly influence this production. first, the exactly determined species must be used and determined in composition. once the raw material is obtained, the process of transformation can significantly influence the composition of the product. the technological transformation is essential to the quality and efficacy of the product. therefore, this second step is vital for the success of the product. the third step consists of the target being assigned to the product and the consequent marketing. in future, natural products will be even more important in the production of new drugs and foods and feeds, able to face the challenges of a continuously changing market. technology is key to this. the natural products market is expanding rapidly in previously unexplored areas, in particular as an alternative to products based on synthetic compounds. the prospects and possibilities in this situation are immense, but knowledge of nature and activity of natural products must be revised utilizing recent devices and research approaches. importance and role of natural products will increase if the multidrug resistance continues, asking for new bacterial and insect possibilities of control. the common composition of a botanical product is based on a single herb or on the combination of more species based on recipes and formulae mainly derived from the historical literature and empirical experiences. the long and accurate work of phytochemistry based on the sequence extraction-separation-identification, derived from the correspondence of one drug to one illness, generated a huge catalogue of identified natural substances that can be employed as useful standards to determine the composition of the botanical drug. the knowledge about composition must be as complete as possible; not a single constituent should be unused, and utility depends strictly on the utilization. natural products are derived mainly from plants as the result of coevolution between organisms and environment (tehri and singh, 2013) . for this reason, they have been used for centuries in popular and traditional medicines, as well as often being employed as spices and insecticides. unlike modern pharmacology and drug development, which are based on a single chemical entity, natural product preparations are multiingredient. a single herbal drug contains at least 100 compounds making a complex matrix, named a phytocomplex, in which the single active constituent is not considered solely responsible for the overall efficacy. the utilization of the phytocomplex is based on experimental basis, since many data afford the validity of this approach, although further confirmations could be obtained using modern pharmacological devices. in other words, the same botanical raw material can be used directly, or extracted in different ways or used as a source of selected substances, or modified according to the product and target. in 2010, a mixed team of experts from mit (massachusetts institute of technology) and the broad institute of harvard university, both in the usa, reported an interesting and innovative study for a scientific evaluation of the effectiveness of natural products. the argument is strictly inherent to the endless debate about the role of natural products and their efficacy, causing a fighting contrast, but useless and boring, between supporters of "natural" versus defenders of synthetic drugs. the key aim of the study was to understand what is going on between the two main levels of the metabolism (primary and secondary), on the basis of the consideration of the functional connection between genes and gene products, as well as between genes and targets. an innovative feature of the study is that the researchers decided to commit the argument to neutral judgment, submitting the elaboration of collected data to the computational work of artificial intelligence. the work was based on the comparison of cumulative connectivity distribution of small molecules, natural or synthetic, grouped according to connectivity associated with the target. assuming that proteins form biological networks and that metabolism and health depend on these networks, we should be able to assign a role to the molecules considered as possible medicines. the result showed that natural products target the proteins with a high number of protein-protein functional interactions (higher network connectivity), whereas the synthetic ones act on a limited protein network. the conclusions of the study, based on a computational approach, were evident: "we observe that approved drug targets that are not also natural product targets exhibit a connection distribution much closer to the case for human disease genes that natural product targets, which remain the most highly connected targets." this sentence indicates a positive and useful consideration about the role and activity of natural products. natural products tend to target more essential and general protein networks to an organism than other groups of small-molecule targets, like those more related to specific disease genes. therefore, the dichotomy between natural and synthetic active constituents must be considered mainly as a consequence of a cultural heritage, unable to assign a complementary or differently appropriate role to the two classes of molecules. the results of the study are coherent with the nature of natural products, whose production is the consequence of environmental interactions, including defense against predators or pathogens. this kind of defense cannot be specific, and therefore natural products act on more highly connected network of proteins, interrupting or limiting the activity of the essential proteins in environmental competitors or invaders. they may be tailored for a positive or negative influence in physiologic activities and basic metabolism of an ample range of organic targets. these arguments are in favor of the potential use of natural products as insecticides. in any case, there are several difficulties in assigning the activity to single constituents, causing several cases of wrong or misleading assignments of all the activity to single substances in the case of a plant extract, like in valerian (valeriana officinalis), whose extracts are largely marketed and utilized for their mild sedative effects. with the discovery of valepotriates, the effects were assigned to these constituents, but after the evidence that extracts with low content in instable valepotriates also exerted similar action, the essential oil was considered additionally responsible for the effect. another case consists of a current debate about hemp. besides cannabinoids, its essential oil and other constituents are now considered important for the multiple activities of hemp. in other words, there are hundreds of marketed products of hemp and many related claimed activities, and this can be related to the complex cannabidioma and/or the different compositions of the products, although they are all derived from the same raw material. it is very important to stress that important new features can appear, also in the case of species highly studied in their chemical composition, as shown in the scientific literature. recently, a new cannabinoid was isolated from cannabis sativa (citti, 2019) . as is wellknown, (à)-trans-δ 9 -tetrahydrocannabinol (δ 9 -thc) is the main compound of hemp and it is considered the main one responsible for intoxicant activity. however, the chemical constitution of this species is subject to high differences in accordance with its varieties and cultivars. cannabinoids possess a unique structure, derived by junction of a monoterpene and a polyketide unit. most of them have a side alkyl chain, whose length influences the biological activity of this cannabinoid. in fact, analogues of δ 9 -thc with a longer side chain were synthetized and they have shown cannabimimetic properties far higher than δ 9 -thc itself (seven c against five). in this study, a new phytocannabinoid with the same structure of δ 9 -thc, but with a seven-term alkyl side chain, was isolated and identified, and its stereochemical configuration confirmed by a stereoselective synthesis. this new phytocannabinoid has been called (-)-trans-δ 9 -tetrahydrocannabiphorol (δ 9 -thcp). the binding activity of δ 9 -thcp against human cb 1 receptor in vitro (k i ¼1.2 nm) proved to be similar to that of cp55940 (k i ¼0.9 nm), a potent full cb 1 agonist. in the cannabinoid tetrad pharmacological test, δ 9 -thcp induced hypomotility, analgesia, catalepsy, and decreased rectal temperature, indicating a thc-like cannabimimetic activity. as confirmation, the corresponding cannabidiol (cbd) homolog with a seven-term side alkyl chain (cbdp) was also isolated and unambiguously identified by matching with its synthetic counterpart. the presence of this new phytocannabinoid could account for the pharmacological properties of some cannabis varieties that are difficult to explain by the presence of the sole δ 9 -thc and indicate the importance of the interaction between constituents of the so-called cannabidiome. therefore, we were not totally surprised when we found good larvicidal activity against aedes albopictus also in nsos with low content in azadirachtins . this was quite a novelty on the basis of the literature, but it is necessary to consider the importance of the metabolomics approach and the possibility with hptlc to obtain several views of the same plates. each view means a revelation of different compounds on the basis of their chemical structure and present functional groups. using an appropriate revelation agent, it is possible to see compounds that are not visible with another derivatization. this approach is contrary to the tendency of current analytical chemistry to focus on a single class of compounds or even unique constituents, which obtain perfect and reliable but limited results. another incongruence consisted of the presence of insecticide activity also in neem products after years of production, when limonoids should be highly degradated. the first experimental evidence we obtained on the activity of neem oil was the inability of the larvae of ae. albopictus to complete the molt from larva to pupa. the larvae proved to be initially immature, their bodies imperfect, and finally before the third instar, most insects died and none was able to fly. the delicate mechanism of the development stage was jammed and the cruel destiny of the unfortunate insects assigned. each organism has its weakness. mosquitos, like any arthropod, possess a rigid exoskeleton, which offers efficient strong and secure protection, also against pesticides, which is one of the reasons for the success of these creatures. the exoskeleton of insects is primarily made of proteins (sclerotin) and chitin (a polysaccharide), which are interwoven and linked together to form strong but flexible bundles. interestingly, chitin is also the main constituent of the fungal cell wall. the ratio of the components of the exoskeleton varies from one body part to another on an insect. however, the exoskeleton is too rigid, and acts like a cover that encases the entire insect, and being a nonliving formation, the exoskeleton does not change size and grow with the insect. the exoskeleton is too ridged to be recycled or modified, and it must be substituted, but it must also protect the insect until the new exoskeleton is ready. during the growth period, insects must shed the exoskeleton in order to assume a new form. as a result, it is necessary for the insect to shed its old exoskeleton to make way for a new, larger one through a process called molting. this is a hormone-controlled phenomenon. during the molting stages, the hormones are released to start and finalize each step of the metamorphosis, until the mature insect finally emerges. however, the chemical constitution of the exoskeleton is variable in each insect species and this is the reason for the selective toxic effects, such as those reported in the case of neem. regarding the structures of insecticides acting as growth regulators, albeit in the case of ecdysones the relation with insect hormones is evident, in other cases the similarity is not so clear, as well as the real mechanism of action. the stages between the subsequent molts are generally called instars. these correspond to altered body proportions, colors, patterns, and changes in the number of body segments or head width. for most insect species, an instar is the developmental stage of the larval forms, but an instar can be any developmental stage including pupa or imago. the larval stage is in particular a delicate stage of the insect metamorphosis. however, we were totally aware that confirmation of the neem insecticide activity, albeit with a demonstrated chemical constitution, in a laboratory experiment was a weak starting point. the open questions were numerous: (a) how to obtain the same result in the field; (b) whether the larvicidal activity could be connected to other properties, in order to improve the use; (c) what the cost of neem oil would be, considering the large-scale spread of the insects; (d) how limited the stability of the active ingredients of neem would be; (e) what determination of chemical content of neem oil would be required, to be connected to the determination of the activity; and (f) what the ambit of utilization would be and the possible damage to the habitat. other advantages arising from the use of neem-based products are the rare induction of resistance, due to their multiple mode of action against pests, the low toxicity rates that have been detected against vertebrates, and finally the necessary environmental care. there is a little confusion about the plant species named azedarach, and very similar denominations. the name azedarach was given by the famous persian physician avicenna (980-1037) to indicate some poisonous trees; however, azadirakhti literally means "free book of india." in 1753, linnaeus reported about melia azadarachta in his species plantarum (1: 385 with habitat: india). in the same book (1: 384), we can find melia azedarach (habitat: syria) and melia azedarach var. sempervirens (habitat: zeylona). actually there are two distinct species, azadirachta indica a. juss, attributed to neem (or nimba, meaning "who gives good health," as reported in the sanskrit books) and melia azedaracht linneus, attributed to melia, a very similar tree. this is the typical taxonomic situation in botany and zoology. the differences between taxa are often very narrow and only specialists are able to find them. in any case, the problem of the significance of these differences is always a matter of debate. god bless taxonomists, because they are necessary to obtain order out chaos, but please do not spend your precious intellect on endless discussions with no final consistent result! in fact, the matter is complicated by synonymous, parental disputes, errors of any type, including wrong transliteration (i.e., gingko and ginko), disputable rules of the international codices, and more. neem and melia are very similar, but there are several tricks to distinguish between the two species. the first is commonly known also as indian lilac and the second one as persian lilac or simply melia. neem has usually white flowers whereas melia presents an explosion of blue flowers; the fruits of the former have an elongated shape, whereas the latter's are totally rounded. if the trees do not have flowers or fruits, and you are not a botanist, you may be in trouble, but you can remember that neem cannot live in temperate climate regions, whereas melia can be easily cultivated in such places. therefore, if you are in europe or the usa, you can be 90% sure on the matter. melia azedarach is known by several common names, such as melia, chinaberry tree, pride of india, bead-tree, cape lilac, syringa berrytree, persian lilac, and others. it is usually a large tree growing up to 30 m tall, with leaves 2-pinnate, rarely 3-, with primary pinnae in two to six pairs, usually three to seven leaflets per pinna, narrowly ovate or subovate, serrate, acuminate, irregularly toothed, or crenate. flowers are abundant and small, sweet-scented, in large axillary panicles. all parts of this tree are reported to have medicinal uses, but in particular, in terms of insecticide properties, seedlings are reported to present aphid attacks. a leaf used as a bookmark will deter insect pests. in italy, the tree is known as the tree of rosary, since in the past, before the advent of plastic, its hard and round kernels were used to make the grains of a rosary. our research on melia azedarach, as well as the references on this plant, evidences a significant difference in the chemical composition. limonoids are present, but different from azadirachtins and other constituents make a marked relevant dissimilarity in composition. the initial conclusion was that melia probably cannot compete with neem as an insecticide, but other utilizations can be explored. however, once again a limit in the references is an irresistible task for a researcher in search of innovations. in addition to the insecticidal properties, we were initially particularly interested in the antimicrobial activity. people often associate antimicrobial activity with infection and effects on their health, but microbes are everywhere and most damage affects cultivation of plants. agricultural methods of reproduction of plants with economic value were totally transformed by the introduction of micropropagation and stem cell culture. micropropagation allows the rapid cultivation of selected cultivars, saving time and resources. however, although the first steps of micropropagation were performed in aseptic conditions, the possibility of infection of calla, shoots, and seedlings is high. avoiding the infection must be done via an appropriate and sensitive approach, avoiding damage to the delicate meristems-a typical job for natural products. the antibacterial study (marino et al., 2014) aimed to investigate the antibacterial activity of unripe fruits of melia azedarach collected in different periods. the activity was tested on the shoots of a hybrid of prunus cerasifera x prunus spinosa and calla lily of zantedeschia aethiopica against several bacterial species. the data reported evidenced a positive antibacterial activity and the absence of any negative effect on the growth of shoots surviving at the second subculture on a standard medium. hptlc analysis showed the prevalence of polyphenols, such as chlorogenic and caffeic acids, which, on the basis of the literature, are consistent with the antimicrobial activity. this activity is important considering that many plant species of economic relevance are now obtained by micropropagation, and this cultivation in vitro is necessary to avoid any sort of contamination. further research is essentially the rational collection of most of the arguments previously considered, as evident in the title: "green-synthesised nanoparticles from melia azedarach seeds and the cyclopoid crustacean cyclops vernalis: an eco-friendly route to control the malaria vector anopheles stephensi?" (anbu et al., 2017) . in this research, once a single-step greensynthesis of silver nanoparticles (agnp) using the seed extract of m. azedarach was obtained, we tested its mosquitocidal activity. in laboratory assays on anopheles stephensi, ag np showed lc 50 ranging from 2.897 (i instar larvae) to 14.548 ppm (pupae). in the field, the application of ag np (10 âlc 50 ) led to complete elimination of larval populations after 72 h. finally, we decided to test the nanoparticles on nontarget aquatic predators. the application of ag np in the aquatic environment did not show negative adverse effects on predatory efficiency of the mosquito natural enemy cyclops vernalis. the reason for this additional research lies in the fact that numerous aquatic arthropods attack and devour preparasites. as we already know, the utilization of the insecticides, though with plant-derived active constituents, could be dangerous for the environmental equilibria. in particular, it could affect the natural biological control, based on the presence predators of the vector in the common habitat, remembering that all the insect stages, except the adult insect, need water. in such sites, there is fresh water everywhere, such as lakes, pools, and similar places, enabling life along the plant-covered banks of stagnant and slow-flowing bodies of water. in such places, mosquitos can proliferate as can any other predator, which in an aquatic environment is fundamental to limit the proliferation of the vector. in fact, after coupling, and the consequent blood feeding necessary to assume the proteins necessary for the eggs maturation, the female is looking for an appropriate place for the deposition of 100-500 eggs. a single anopheles, like other insect, is able to produce a quantity of eggs and larvae enough to invade all the neighboring habitats, as in the classic case of a locust invasion. this is not possible only thanks to the natural enemies. the microaquatic environments are the scenario of a continuous fight for survival, where often two or more species of arthropods are involved, as predator or as prey. in our study, we selected the genus cyclops, which is one of the most common of freshwater copepods, comprising more than 400 species. copepods are very little crustaceans, commonly called water fleas. they have a single large eye, which may be either red or black, and therefore they are named for the cyclops of greek mythology. cyclops prefers fresh water, and is less frequent in brackish water, where it feeds on small fragments of plant material, animals, or carrion. it swims with characteristic jerky movements and has the capacity to survive unsuitable conditions by forming a cloak of slime, with an average lifespan of about 3 months. several microscopic crustaceous, including copepod species, feed small and very small preys. in high-density, unstructured environments such as eutrophic lakes, predatory copepods commonly coexist with certain smallbodied prey, where encounters are frequent with ineptness on the part of the predator and counter-tactics by the prey. in particular, laboratory studies showed that copepods are effective predators on early-instar culex larvae, involving an important role in suppressing mosquito populations, because of their feeding behavior and abundance. they are very efficient in this role, since the presence of alternative abundant food, like bacteria and protozoa, does not deter their attacks on their preferred prey. copepods are capable of killing and eating at least four preparasites within 13 min and a predator density of 53 copepods/liter is expected to reduce the mosquito larvae by 50%, with the rate of predation inversely proportional to the water volume. neem cake: from by-product of an industrial process to multipurpose resource for a sustainable agriculture chain during our research activity, we were highly interested in industrial plantborne by-products, since they can offer new products to the market with lower cost and high usefulness. our attention was immediately attracted by neem cake, a cheap by-product of nso extraction, obtained as a residue after mechanical pressing of the neem seeds, considered of low economic value and utilized to enrich the soil of some mineral components, such as nitrogen. the laboratory test indicated neem cake activity against aedes albopictus and a number of culicidae species (nicoletti et al., 2010) . in the case of biocidal treatments, it is important to demonstrate that insecticide activity is associated with antimicrobial activities in consideration of the high possibility of infection and the severe consequences for health, in particular in the case of the animals, both pets and livestock. the importance of insecticidal and antimicrobial activities for animal treatment has been evidenced in the experiments with nso and neem cake further reported, including larvicide, deterrent, and repellent activities (benelli et al., 2015a,b; nicoletti et al., 2012a,b) . the complex range of different compounds in the neem seeds open the possibility to utilize the derived products to solve many current problems. the challenge now is to obtain marketed products tailored for different utilizations. the reported experiments evidenced these potentialities, which are only waiting a realization and a wider utilization. despite diseases, wars, and environmental disasters, the human population is growing. first of all, more people will need more food. this forecast shows in particular a massive increase in animal protein demand, needed to satisfy the growth in the human population, wherein billions of people require an increase of caloric input and better food. therefore, attention is focused on the sources of feed protein and their suitability, quality, and safety for future supply. in addition, the quantitative production aspect is causing a series of problems. there will need to be a considerable increase in feed manufacture, requiring a thriving, successful, and modern feed industry, including a key aspect concerning the protection and preservation of the food produced and marketed. this aspect is strictly related to safety issues, which will remain paramount in the minds of consumers following recent food crises. it is time to consider that the need of more food to feed due to increasing planet population perhaps cannot simply be solved by massive production, but reduction of food waste and conservation can increase food availability by 30%-40%. "feed the planet and energy for life" was the theme of world expo 2015 in milan, italy. among the activities occurring at the expo, research and proposals concerning the utilization of neem products were presented in a call for projects in favor of sustainable progress and production of future foods. the neem project was selected as the best one due to its possible applications in the production of food and feed. the expo event projected feeding as the main challenge for humankind and showed the extreme urgency of elements of innovation in technology and science connected to the production and conservation of food. it was demonstrated how serious feed problems still plague several areas of the world today, and the possibility of new solutions was mentioned. the neem project was focused on the agricultural utilizations of neem cake concerning its advantages as soil fertilizer and as a natural ectoparasiticide for the treatment of sheep and goats. neem products were proposed as being able to affect the biotic composition of the soil. neem cake must be preferred to neem oil for its cost and its form as a powder immediately available. several experiments evidenced the improvements of the utilization of neem cake in agrarian ecosystems: (1) availability of nutrients, in particular nitrogen and phosphorus, more consistent with the requirements of the crop; (2) development of the microbial beneficial biomass of the soil, which increases in quantity and activity, but with selective influence against nematodes and other negative components. in agricultural practices, plants in addition to nutrients should count on a greater variety of useful microorganisms and on acquisition of nutrients themselves, through the activation of complex symbiotic systems. if you want to understand the state of health of a tree, you must look down, not up; and (3) development of pest control system of insects and other arthropods of agricultural and livestock interest. neem cake, as an industrial by-product, is a heterogeneous material that maintains a high added value due in large part to its chemical composition, which confers its biological activity. neem cake is widely available on the global market, considering the increasing presence of neem trees in the world and production of nso. the exploitation of its characteristics in the food chain to improve consumer health, increase the productivity of agricultural products, and feed the planet is the logical consequence of the urgent need to develop new sustainable agricultural systems in a world where many highly polluting pesticides are no longer allowed to be used. however, more research, in particular in field conditions, is necessary to understand the real value of its microbiological, insecticide, fertilizer, and nematocide activity, involving collaborations between different experts in individual sectors-import companies, organic farms, and research institutions-in order to determine the manner and timing of land application of this valuable product of "waste," still underestimated. neem cake could lead to a revolutionary improvement in the fertilization of agricultural plants, adding to the characteristics of chemical fertilizers those of a soil improver. in agriculture, we could define neem cake as a prompt nutrient-release fertilizer, effective in allowing rapid absorption of nutrients and promoting development of the plant, with the capacity to increase the activity of the microbial biomass and organic matter, favoring the sequestration of carbon. the idea was to join the fertilizer, insecticide, and antimicrobial utilities of neem cake. exploitation of the use of neem cake as an insecticide came from this first test: some pots of impatiens (impatiens balsamina) were fertilized with 3% by volume of neem cake, and 500 mosquito larvae were reared starting from eggs. the eggs were hatched in control and treated in pot saucers, but none of the newborn larvae survived in the water saucers of pots treated with neem cake, while in the water saucers of pots unfertilized with cake, the 500 control larvae completed their development in less than a week, becoming adult mosquitoes. other major beneficiaries of the use of neem cake as insecticide are undoubtedly sheep farmers, who can use an organic product of natural origin and low cost that is simultaneously effective against the larvae of culicoides and other pests, while respecting the natural biotic communities. direct beneficiaries of neem cake, as a fertilizer, are farmers seeking pest and nematode control, in particular for nematodes. currently, some highly toxic products are still on the market by virtue of the absence of suitable alternatives. particular attention must be focused on the changes on soil micro-composition, as evidenced in several field experiments. in conclusion, we can report the following important advances in the use of neem cake as a functional fertilizer: (a) energy saving flows from the use of a waste of an industrial chain; (b) environmental sustainability, as documented by the analyses attesting the absence of heavy metals, aflatoxins and residues of pesticides; (c) neem cake is an excellent alternative to methyl bromide (bm) (banned as being responsible for the "thinning" of the ozone layer of the atmosphere); (d) neem cake is an excellent alternative to temephos and other organophosphates used to treat water infested with disease-carrying insects including mosquitoes, midges, and blackfly larvae; (e) neem cake is a great alternative to nematicides, like 1,3-dichloropropene; and (f) neem cake in the field trials carried out in sardinia had efficacy similar to azadirachtin biological products already established in organic farming, but were very expensive and not really effective. in addition, neem cake showed very low effect on "nontarget" insects that live in the same environments as culicoides larvae. ectoparasites are organisms that inhabit the skin of another organism, causing significant infestations and pathologies. many micropathogens can profit from the work of ectoparasites, either to colonize the skin injury and lesion, or be inserted in the host during the feeding. the vast majority of ectoparasites are arthropods, e.g., insects and arachnids. again the triangle host-vector-etiological agent is reproduced. many ectoparasites are vectors of pathogens, which are typically transmitted while feeding on or from other hosts. several ectoparasites (e.g., most lice) are host-specific, including livestock, pets, poultry, fish, and bees, but others parasitize a wide range of hosts, including humans. typical effects of infection on the host are irritability, dermatitis, secondary infection (other parasites profit of the skin necrosis), fecal hemorrhages, blockage of orifices, inoculation of toxins, and exsanguination. as a consequence, the host's general health can be seriously affected with low weight gains, particularly important in livestock. subdermally located parasitic larval stages of certain flies can be favored by the ectoparasited infection, causing a condition termed "myiasis." when insects (order hemiptera) are involved, the infection mechanism is similar to that previously described for any insect-borne disease. the vector contains several hematophagous ectoparasites, including approximately 150 species of kissing ("cone-nose") bugs (reduviidae, triatominae) and bed bugs and bat bugs (cimicidae). these parasites make physical contact with the host principally when ingesting a blood meal. these kissing bugs usually prefer domestic animals, from which relatively large blood volumes may be imbibed; in such a way they can cause a great deal of damage and transmit important diseases. ectoparasites play a very detrimental role in terms of decreasing the productivity of livestock, such as sheep and goats. nso was utilized in the field as an antibacterial in the case of ectoparasites' stings and bites resulting from goat wounds. common external sheep and goat parasites include ticks, lice, and mites. they cause restlessness and irritation. weight loss and reduction in milk production may occur as a result of nervousness and improper nutrition, because animals spend less time eating. bites can damage sensitive areas of skin (teats, vagina, eyes, etc.) . some parasites feed on blood, causing anemia, especially in young animals. the bite and the sting of ectoparasites allow bacteria to proliferate in wounds from abrasions or lesions from scratching, and cause levels of tissue reaction of different entities, super-infection, and cervical lymphadenopathy. ectoparasites cause many problems in livestock production. they seriously damage sheep and goat skins, resulting in the rejection or downgrading of the skins. this causes huge economic loss, as this skin damage renders it unsuitable for the leather industry due to the decrease in quality. lower production of meat is also a typical consequence. pseudomonas aeruginosa wound infections are characterized by a change in the color of the skin around the wound area and the formation of lesions. the bacterium products and pigment cause yellow discoloration of wool and consequently reduced quality and market value. nso treatment in the field on as a natural ectoparasiticide for sheep and goats proved to be successful in preventing and curing the attacks of endoparasites ( fig. 7.16) . the experiments were performed on selected livestock (fig. 7.17 ) by a specialized team of crea researchers (de matteis et al., 2015) . the effects on the parasites were evident (figs. 7.18 and 7.19) and even after the first treatment with nso, protection against ectoparasites was obtained. more important, the health of the treated livestock improved, as testified by the hematological profile of goats. in vivo and in vitro tests on blood cells from siriana, sanen, cashmere, and maltese goat (capra hircus) breeds showed no significant difference (p <.05) between nso treated and untreated goat hematological parameters at each sampling time considered. in addition, the nso effect on goat pbmc cultured in rpmi medium was evaluated at 1:2â102 to 1:20â106 dilutions at 14, 21, and 40 h of exposure. the in vitro test revealed that the response of goat pbmc viability is dependent on concentration, incubation time, and nso dose. in conclusion, the nso should be considered useful, safe, and innovative for development of topical solutions for the care of wounds. among the most relevant typology of neem products, we focused on selectivity. the antibacterial activity of nso was assayed against 48 isolates of escherichia coli, considering that this bacterium can produce beneficial and pathologic populations. the molecular biology characterization showed that 14 isolates resulted in diarrheagenic e. coli. nso showed biological activity against all isolates. however, there were significant differences between the antibacterial activities against pathogenic and nonpathogenic e. coli, as well as between nso and ciprofloxacin activities. on the basis of the results obtained, nso is able to counteract e. coli and also influence the virulence of e. coli-viable cells after treatment with nso. the preservation of marketed food is an important aspect of the smart utilization of the produced food (maruchecka et al., 2011) . furthermore, the consequent waste of unutilized food is a relevant problem in overcrowded towns (hlpe, 2014) . a large quantity of food is lost or wasted throughout the supply chain, from initial agricultural production down to final household consumption (hlpe, 2014; kader, 2005) . the loss or waste for high perishable food, such as fresh fruit and vegetables, fish and livestock products, has been estimated at as much as half of all food grown before and after it reaches the consumer. approximately one-third of all ffvs produced worldwide are lost during food supply chain production. shelf life plays a central role in food spoilage. the impact of the enormous quantity of packaging is evident in any planet environments. increase of the shelf life means reduction of cost and waste. everything pivots around the material utilized for packaging, and new solutions are emerging (otoni et al., 2016; singh and singh, 2005; cooksey, 2005; appendini and hotchkiss, 2002) , including passive packaging (brockgreitens and abbas, 2016; ozdemir and floros, 2004) , active packaging (coma, 2008) , intelligent packaging (lee et al., 2015; de kruijf et al., 2002) , and smart packaging (dobrucka and cierpiszewski, 2014) . although the results are not evident in our ordinary life, the galaxy of packaging is rapidly moving and increasing in research and proposals, based on new technologies and advanced techniques recently available, like nanotechnology and molecular biology. efforts are focused on solving the food preservative problems, to extend the shelf life of perishable foods, by reducing the need for additives and preservatives. "smart packaging" is based on the production of functional methods to obtain the following goals: be tailored depending on the product being packaged, including several types of food, beverages, pharmaceuticals, household products, etc.; reduce food waste, increasing the shelf life; and maintain, and eventually enhance, product attributes (e.g., look, taste, flavor, aroma). the key words are protect, preserve, and present. several methods and approaches, such as oxygen scavenging and antimicrobial technologies associated to the production of modified films, have been considered . they are different solutions to serve the basic and fundamental properties of packaging. so far, the dominant packaging is the basic one, using low-cost material and involving no interaction with the food inside. this is passive packaging, wherein the traditional packaging systems are included, as the use of covering material characterized by some inherent insulating, protective, or ease-ofhandling qualities. usually, the ordinary packaging of food is mainly a used to method to attract and select the consumer, beside a preservation. the consequence is the enormous amount of waste, and the consequent damage to the environment. this situation is increasing due to the increasing numbers of consumers in emerging countries, where these consequences are not adequately considered. packaging is considered active when it can interact in the same way and/or react to various stimuli, in order to keep the internal environment favorable for the maintenance of product quality. several environmental, biotic, and abiotic factors must be considered, in order to respond to the degradation process successfully. the activity involved could be the presence of an oxygen scavenger (this can absorb high-energy oxygen inside a package and therefore increase the shelf life of a product) or an anti-ros (a scavenger of radicals by oxygen or other origins), such as in the typical case of phenolic natural products. smart packaging relies on the use of chemicals, electrical, electronic, or mechanical technology, or any combination of these. technology is used to modify the packaging by adding constituents to change its features and properties (kerry et al., 2006; malhotra et al., 2015) . active and intelligent packaging is particularly dedicated to the preservation of fresh products, like vegetables, in accordance with increasing requirements for this kind of food (nicoletti and del serrone, 2017; nicoletti, 2014a,b) . intelligent packaging systems monitor the condition of packaged foods to give information regarding the quality of the packaged food during transport and storage (aguilera et al., 2003) . probably the most innovative aspect of intelligent packaging is that it can be supported by the utilization of systems of detection in meat and meat products, obtained through the use of sensor technologies indicators (thakur and ragavan, 2013) , including integrity, freshness, and time-temperature indicators (ttis) and radio frequency identification (rfid). therefore, active and smart packaging performs additional functions to the basic one by the introduction of innovations in the design of packaging, with the aim of increase the shelf life, but also to add conveniences for the user and usefulness for the consumer, to be introduced also in the supply chain. in this way, the product can respond not only to the need for a longer life, but also make the product more available, more useful, and more safe. since our invisible enemies are asked to play their role again, antibiotic activity is required. packaging is mainly used to separate food from environmental conditions, utilizing simple material made of paper or plastic. however, it cannot prevent internal attacks by microorganisms, but can only limit or delay the effects. therefore, additional treatments are required to limit their action, like the utilization of low temperatures, which involves additional costs and energy consumption and pollution. a new idea is to associate to the packaging some antimicrobial agent. before and during packaging, storage, and shelf life, food is subjected to a continuous attack by microorganisms. these microorganisms are working to benefit themselves by demolishing progressively the molecular structure of the food, as soon and as completely as possible. therefore, by preserving the food, we are working in a thermodynamically unfavorable situation. in term of shelf life, the food is in competition with its natural recycling, and, working to maintain as possible this limbo, we can utilize the food efficiently as it is possible. the resistance phenomenon interests also zoonotic food-and waterborne pathogens becoming more resistant to antibiotics (del serrone et al., 2006) . resistant strains of pathogens have been isolated from food, causing an increasing incidence of food-borne diseases. through the food, these microorganisms could be entering the human gastrointestinal tract on an almost daily basis. the antimicrobial activity of nso and related products have already been reported (palanappian and holley, 2010; baswa et al., 2001; sairam et al., 2002) . a possible utilization of antibacterial activity of neem cake against meat spoilage bacteria was tested using a broth model meat system . the tests were positive, since the growth inhibition zone (mm) varied significantly (p!.05). with respect to ciprofloxacin activity, the antibiotic value ranged as follows: 11.33 ae0.58 to 22.67ae0.58 mm and 23.41ae1.00 to 32.67 ae2.89 mm, respectively. the percentage of bacterial growth reduction (gr%) also varied significantly (p !.05) in function of considered nce concentrations (1:10-1:100,000), with the highest gr% for 10 μg nce (79.75 ae1.53 to 90.73 ae1.53). the numbers of viable bacterial cells never significantly (p .05) exceeded inocula concentrations used to contaminate the meat. all the results of the experiments showed that neem cake is able to counteract the main microorganisms responsible of meat spoilage, like strains of gram-positive and gram-negative, as well as facultative anaerobic bacteria. the antimicrobial activity of neem products was confirmed also for nso against spoilage bacteria, such as carnobacterium maltaromaticum, brochothrix thermosphacta, escherichia coli, pseudomonas fluorescens, lactobacillus curvatus, and l. sakei. after the second day after nso, only c. maltaromaticum-viable bacterial cells were detected. these data could be used to create new intelligent packaging. utilizing a nanotechnology already employed for other materials, neem cake may be incorporated into the cavities of nanoparticles, maintaining its antiparasite activity. once incorporated into the packaging material, the neem cake, also in minimum quantity, should be able to effect its preservative food action, acting against the demolishing microorganisms. the increase of the shelf life of meat should compensate for the additional cost of the packaging material, not considering the decrease of waste. it is possible that the first activity of luca was to find the energetic source for survival, and the second was to compete with the other lucas. the results are an endless transformation of forms and production of new molecules. the living organisms had a long time to organize their molecular weapons and the secondary metabolites are there, produced and organized to be considered and utilized in the right way. the neem tree is an example of nature's treasure. the advent of homo sapiens (lucy) changed in part the rules of the natural game, but natural products still remain a necessity for our life. recently, parenteral artesunate has replaced quinine and many other antimalarial products for the treatment of severe malaria. however, several reports have demonstrated the emergence of resistance to the efficacy of artemisinin-based combination therapy monotherapy, such as in western cambodia and other regions in south-east asia. to face the phenomenon, artemisinin-based combination therapies are now recommended by the who. the aim is to reduce the morbidity and mortality associated with malaria with artemisinin-based combination therapies, including chloroquine plus other drugs, like sulfadoxine-pyrimethamine. meanwhile, with increasing resistance to chloroquine, quinine is reconsidered, being so far the only substance for which plasmodium did not develop resistance. the consequences are that in uganda quinine was prescribed for up to 90% of children younger than 5 years with uncomplicated malaria, and from 2009, 31 african countries recommended quinine as a second-line treatment for uncomplicated malaria, 38 as a first-line treatment for severe malaria, and 32 for treatment of malaria in the first trimester of pregnancy. recent surveillance data from other sites are in accordance. however, quinine was substituted due to its limits and therefore in 2010, who (2010) guidelines recommended reinforcing quinine's activity by combining it with other antimalarial agents, like doxycycline, tetracycline, or clindamycin as a second-line treatment for uncomplicated malaria (to be used when the first-line drug fails or is not available) or quinine plus clindamycin for treatment of malaria in uncomplicated cases and in the first trimester of pregnancy. the development of effective cocktails is a current trend of medical treatment of several diseases, including forms of cancer. in addition, the combination of natural products and synthetic drugs is recommended. natural products can be utilized as resistance-modifiers or chemosensitizers, and may be able to restore chloroquine sensitivity in resistant strains of plasmodium. the idea of 8 years of research from different research groups was that the antimalarial treatment combined with natural products could be based on lower doses of chloroquine, in order to minimize the resistance insurgence and to avoid the collateral effects in the case of prolonged use, necessary in areas where the disease is endemic. this approach came from an ethnopharmacological investigation by professor rasoanaivo (rasoanaivo et al., 1992) . most people consider ethnopharmacology to be a collection of ancient utilizations of natural sources, and as knowledge that is going to disappear. on the contrary, in addition to traditional uses there are new ones emerging, even as consequences of the utilization of modern drugs. considering that oms reports that 80% of the planet population relies on traditional medicine, the utilization of medicinal plants is not limited to ancient times and past populations, but it changes according to needs and evolution of treatments. ethnobotanical knowledge is still passed from one generation to another in the majority of populations living in rural areas, and in urban areas, where malaria has been revealed to be resistant or incurable by modern scientific medicines, people have turned to traditional treatments. it is therefore of paramount importance to preserve and transmit this ethnobotanical heritage. therefore, this discipline must be regarded as a multidisciplinary science in movement, where botany, chemistry, and pharmacology play central roles for scientific evaluation and validation of popular uses. however, economic and social aspects must also be considered, in order to develop new drugs and treatments of both old and new diseases. most antimalarial drugs currently in use belong to the classes of aminoquinolines (chloroquine, amodiaquine, primaquine), quimolinomethanol derivatives (quinine, mefloquine, halofantrine), diaminopyrimidines (pyrimethamine), sulfonamides (sulfadoxine, sulfadiazine), biguanides (proguanil and derivatives), antibiotics (tetracyclines, doxycyclin, clindamycin), sesquiterpenes (artemisinin, dihydroartemisinin, arteether, artemether, artesunate) , and naphtoquinones (atovaquone). among them, only quinine and artemisinins are natural products, but also a relevant part of the current antimalarial arsenal. the potentiality of natural products is very high. a review by willcox and bodeker (2004) on traditional herbal medicines for malaria in three continents reported 1277 plant species from 160 families. however, the clinical trials are largely lacking, since only eight clinically controlled trials have been reported, involving p. falciparum and p. vivax. in the case of malaria, alkaloids are the first candidates responsible for the activity. there is a long tradition in popular medicine of plants containing these compounds to control fever. these plants also have a bitter taste, which is usually connected to the alkaloid presence, as already reported for the aforementioned quinine bark case. two important considerations attracted our attention, in view of the possibility to explore new strategies: the special endemic flora of madagascar and the occurrence of information about a popular treatment of malaria as yet unreported. madagascar is a land of endemism, consisting about 13,000 species of vascular plants, of which 80% are endemic, and eight families totally endemic. malaria is practically endemic in all madagascar and therefore the population harbors a very rich and unique knowledge on antimalarial plants. after a resurgence of malaria in the early 1980s, as a consequence of plasmodium falciparum resistance and due to the high costs of conventional drugs, local populations returned to the uses of herbal remedies. two hundred and thirty-nine plant species, of which about 30% are endemic to madagascar, have been reported as having antimalarial uses in malagasy traditional medicine. prof. rasoanaivo discovered the use by some populations in madagascar of decoctions of some local plants in association with low doses of chloroquine to complement chloroquine action against chronic malaria . the lower use, one or two tablets of chloroquine (100-200 mg), is probably adopted to avoid collateral effects due to prolonged use of chloroquine, but such a dose could be considered inadequate to favor chloroquine resistance. therefore, we have a mixture of recent learning and ancient knowledge, evidencing the reality of ethnopharmacology. however, popular uses of medicinal plants need scientific validation with advanced tools. therefore, research started from the knowledge that some populations in madagascar use decoctions of some local plants in association with low doses of chloroquine to complement chloroquine action against chronic malaria. in such a way, resistance insurgence and collateral effects are both lowered. on the basis of the ethnobotanical work conducted by rasoanaivo and his collaborators, 24 plants were selected and investigated for in vitro and in vivo antimalarial activity and a chloroquine-potentiating effect. in the case of validation of the activity, the determination of the active constituents followed. the results of these selections were that the alkaloids of loganiaceae, menispermiaceae, and rutaceae were the most promising compounds showing significant effects, some of them potentiating the action of chloroquine. from a phytochemical point of view, alkaloids are in pole position among natural products utilized in traditional medicine against malaria. mono-and bis-indole alkaloids have been isolated from several plants that are traditionally used to treat malaria on different continents. the most active compounds are those that originate from plants belonging to the genera strychnos (loganiaceae) and alstonia (apocynaceae). a review covering the indole alkaloids that have high antiplasmodial activities in vitro and in vivo, and favorable selectivity indices (si¼cc 50 /ic 50 ), was published by frederich et al. (2003) . in the case of malaria, alkaloids are the first candidates as being potentially responsible for the activity. there is a long tradition in popular medicine of plants containing these compounds to control fever. these plants also have a bitter taste, which it is usually connected to the alkaloid presence, as already reported for the aforementioned quinine bark case. two important considerations attracted our attention, in view of a possibility to explore new strategies: the special endemic flora of madagascar and the occurrence of information about a popular treatment of malaria so far never reported. madagascar is land of endemism, consisting about 13,000 species of vascular plants, whose 80% are endemic, and even 8 families totally endemic. malaria is practically endemic in all madagascar and therefore the population harbours a very rich and unique knowledge on antimalarial plants. after resurgence of malaria in the early 80's, as a consequence of plasmodium falciparum resistance and due to high costs of conventional drugs, local populations back to the use of herbal remedies (blanchard, 1901; maggi et al., 2017) . two hundreds and thirty-nine plant species, of which about 30% are endemic to madagascar, have been reported as having antimalarial uses in the malagasy traditional medicine. prof. rasoanaivo discovered the use by some populations in madagascar of decoctions of some local plants in association with low doses of chloroquine to complement cq action against chronic malaria . the lower use, one or two tablets of chloroquine (100-200 mg) , is probably adopted to avoid the collateral effects due to a prolonged utilization of chloroquine, but such dose could be presumed inadequate to favour chloroquine resistance. therefore, we have a mixture of recent acquirement and ancient knowledge, evidencing the actuality of ethnopharmacology. however, popular uses medicinal plants need a scientific validation with advanced tools. therefore, the researches started from the knowledge that some populations in madagascar use decoctions of some local plants in association with low doses of chloroquine to complement chloroquine action against chronic malaria. in such way, resistance insurgence is lowered, as well as collateral effects. on the basis of the ethnobotanical work conducted by rasoanaivo and his collaborators 24 plants were selected and therefore investigated for in vitro and in vivo antimalarial activity and a chloroquinepotentiating effect (maggi et al., 2017) . in case of validation of the activity, the determination of the active constituents followed. the results of this selection were that the alkaloids of loganiaceae, menispermiaceae and rutaceae were the most promising compounds showing significant effects, some of them potentiating the action of chloroquine. mono-and bis-indole alkaloids are traditionally used to treat malaria in different continents (ramanitrahasimbola et al., 2001 (ramanitrahasimbola et al., , 2006 . the most active compounds were mainly related to the genera strychnos (loganiaceae) and alstonia (apocynaceae). a review covering the indole alkaloids that have high antiplasmodial activities in vitro and in vivo, and favourable selectivity indices (si¼cc 50 /ic 50 ) was published by frederich et al. (2003) . strychnos is a pantropic genus, with about 200 species, present in three continents: 75 in africa, 73 in america, and 44 in asia and oceania (only s. potatorum is present in both asia and africa). asiatic species are mainly small trees, whereas in the new world lianes are generally dominant. the most famous strychnos species is the asiatic s. nux-vomica, because of strychnine contained in the seeds with 12 other related alkaloids. strychnine is also known and used for its bitter taste. south american species are characterized by different mono and bisindole alkaloids, important as constituents of some curare preparations of indios amazonia tribes (see introduction) . during the preparation of curare, the tribe curandero selects local plants and extracts the mixture by hot water. finally, the extract is filtered on leaves and concentrated to obtain a paste, which is preserved into a container, like a calebassa or a tube, maiden by a cane, or a pottery. active constituents in curare are bis-indole alkaloids from bark of strychnos ssp. and bis-tetrahydroisoquinoline alkaloids from menispermaceae. the genus strychnos is represented in madagascar by 14 species, of which five are endemic to the island. among them, s. diplotrocha leeuwenberg and s. myrtoides gilg & bussse are used as antimalarial in the northeastern part of the country (rasoanaivo et al., 2004) . the phytochemical analysis allowed the separation and the structural determination of several indole alkaloids, some already known and others never reported, including mixtures of epimers, which is very unusual in the same plant (rasoanaivo et al., 1991 (rasoanaivo et al., , 1996 (rasoanaivo et al., , 2001 . the in vitro and in vivo chloroquine-potentiating effect of the crude extract of dried and powdered stem barks of s. myrtoides exerted chloroquine-potentiating effects on p. falciparum fcm29, but it was devoid of intrinsic antimalarial activity. the extract was also devoid of cytotoxic effects on hela and l 929 fibroblast cells. the two compounds exhibit a closely related structure but different basicity. therefore, the latter parameter can be excluded from the factors affecting the chloroquine-potentiating effect. these results were confirmed by other experiments, demonstrating that the crude extract of s. myrtoides showed higher chloroquine-enhancing activity than its major bioactive constituents. these data support the use of the plant as a phytomedicine to treat malaria, but minor components of the extract may act synergistically. among the main isolated alkaloids, malagashanine was very interesting. malagashanine is an unusual indole alkaloid of the strychnos type. its pentacyclic structure contains seven consecutive stereogenic centers and, most important, a transfusion between the c and d rings, against all the other similar natural alkaloids. therefore, malagashanine is the parent compound of a new type of indole alkaloids (fig. 7 .20) (kong et al., 2016) , named n b c(21)-secocuran, isolated so far from the malagasy strychnos species, which are traditionally used as chloroquine adjuvants in the treatment of chronic malaria (rasoanaivo et al., 1996a (rasoanaivo et al., , 2001 . malagashanine showed only weak in vitro intrinsic antiplasmodial activity (ic 50 ¼146.5ae 0.2 μm), but did display marked in vitro chloroquine-potentiating action against the fcm29 chloroquine-resistant strain of plasmodium falciparum. another study allowed clarification of the mechanism of action of the major constituent, malagashanine, being able to prevent chloroquine efflux from the cell, and stimulates chloroquine uptake into drug-resistant p. falciparum strains. malagashanine appears able to act more on plasma membrane than inside the parasite, allowing the toxicity of chloroquine against plasmodium, even at sublethal doses. in the attempt to confirm the reversal of chloroquine resistance by the bark of s. myrtoides, a double-blind randomized controlled clinical trial of a standardized alkaloid extract titrated at 20% malagashanine took place in a government-run outpatient clinic in the town of ankazobe (northwest central highlands of madagascar), but the results of the treatment showed no significant efficacy, indicating a need for other confirmations. however, in conclusion, the approach, in accordance with recent tendencies on multidrug resistance control, based on mixtures of natural products and classic antimalarial drugs, with a relevant coincidence between the ethnobotanical reports and the scientific evidence, may offer interesting possible solutions for the treatment of malaria. many aspects about the mechanism of action of malagashanine as chloroquine adjuvant to reverse the resistance need further study. malagashanine could increase drug accumulation by interacting with a dysregulated ion exchanger, avoiding the decrease inside the food vacuole, or acts by a mechanism related to drug binding to hematin (perisco et al., 2017; rafatro et al., 2000) . in particular, in relation to the ph role in the blood red cell, it would be necessary to determine if malagashanine acts inside or outside the food vacuole, including the membrane periphery. the capacity of malagashanine to reverse cq resistance may be related to the well-known properties of verapamil ( fig. 7 .21) and related substances (martin et al., 1987; martiney fig. 7 .21 verapamil and other compounds studied for cq-resistant reversal by membrane calcium channels blocking. adovelande et al., 1998) . verapamil was the first calcium channel antagonist to be introduced into therapy in the early 1960s. it is a phenylalkylamine calcium channel blocker used in the treatment of high blood pressure, heart arrhythmias, and angina. in short-term incubations, verapamil was found to increase chloroquine accumulation in the lysosome of erythrocytes infected with both chloroquine-sensitive and -resistant organisms, but only to affect the chloroquine susceptibility of the latter. verapamil works independently of the overall ph gradient concentrating cq into a trophozoite's digestive vacuole. the activity is therefore related to the inhibition of membrane ion channels, interfering in the chloroquine transit within the parasite's cytoplasm. other substances like chlorpheniramine and others are reported as candidates for cq-resistant reversers. in any case, again the key role of natural products and ethnoparmacology information, such as for quinine (cinchona sp.) and artemisinin (artemisia annua), is fully confirmed. another attempt to explain the activity of malagasy plants alkaloids explored the role of glutathione. l-glutathione reduced (gsh) (fig. 7.22) is a simple tripeptide, consisting of glutamic acid, cysteine, and glycine. it is considered one of the most powerful endogenous antioxidants, capable of preventing damage to cellular components caused by reactive forms of oxygen, radicals, and heavy metals, although its role in stress management and efficient defense against pathogens are still under study (mangoyi et al., 2010) . besides its antioxidant defense and free radical scavenging, glutathione regenerates important antioxidants such as vitamins c and e. gsh exists in every cell of the human body, but it is also present in many other organisms, including fungi and bacteria. there is a linkage between gsh and malaria. some parasites are superprotected by gsh. they are endowed with powerful and host-independent mechanisms, which de novo synthesize or regenerate gsh and protect the parasites from oxidative damage and other outside attacks. gsh in particular protects the gametocytes against oxidative stress and inhibits the action of arginine, which produces no and expels it from the food vacuole. at the trophozoite stage of p. falciparum in human erythrocytes, gsh takes part in detoxifying processes of heme, produced by hemoglobin digestion, by polymerizing some 30% of heme to insoluble hemozoin. some authors suggest that the nonpolymerized heme, existing in the food vacuole, is subsequently degraded by gsh, increasing the role of this metabolite. chloroquine could interact with gsh, competitively inhibiting the degradation of heme by gsh or allowing toxic heme to accumulate in membranes and damaging parasites. this argument merits some explanation. the prooxidant damage and inflammation process created by excessive heme, hemozoin, and fragments from rupture of the digestive vacuoles in blood vessels and plasma can be mitigated by glutathione. in other words, the inside of the infected erythrocyte glutathione is beneficial to the parasite; outside of the erythrocyte it reduces the negative effects of the malarial infection. high oxidative stress could actually be detrimental for the survival of young parasites (gallo, 2009; patzewitz and m€ uller, 2010) . glutathione transferases (gsts) are versatile enzymes involved in the intracellular detoxification of numerous substances. gsts have been investigated in parasite protozoans, like those involved in malaria, with respect to their biochemistry and as targets in synthesis of new antiparasitic agents. p. falciparum possesses high quantity of these enzymes (pfgst) and their activity was found to be increased in chloroquine-resistant cells, and it has been shown to act as a ligand for parasitotoxic hemin. pfgst represents a promising target for antimalarial drug development. a pfgst isolated from p. falciparum has been associated with chloroquine resistance. plant extracts have been found to act at different vulnerable metabolic sites of pfgst, disturbing gsh-dependent detoxification processes, increasing cytotoxic peroxides levels and possibly increasing the concentrations of toxic hemin in the parasites. in the case of s. myrtoides alkaloids, malagashanine was found to prevent chloroquine efflux from and stimulated chloroquine influx into drug resistant p. falciparum, suggesting that its effects are more on the plasma membrane than inside the parasite. malagashanine (100 μm) reduced the activity of pfgst to 80%, but showed a time-dependent inactivation of pfgst, suggesting a role of malagashanine as a chemomodulator in cases of pfgst overexpression in chloroquine-resistant strains. the malaria cycle of a parasite is based on two cycles, one involving the host and the other affecting the vector. during the mosquito cycle, again there are metamorphoses and reproduction by the parasite. in consideration of the resistance phenomenon, new transmissionblocking agents, able to interrupt malaria transmission, are required. these blocking drug components can be effective in reducing gametocyte density in the human host (gametocytocidal activity) or disrupting parasite development in the vector (sporontocidal activity), resulting in a reduced number of infective vectors and, as a consequence, decreased incidence of malaria cases. in other words, control malaria's parasites through the cure of the vectors infested by the disease. in the sexual stages of plasmodium parasites, gametocytes are critical for the transmission of the parasite to its vectors. p. falciparum gametocytes are also important in the disease diffusion, since being exceptionally long-lived, they cause clinically cured patients to be reservoirs of infection. the cycle of propagation of the malaria parasites starts when the female anopheles feeds on blood from an infected vertebrate. immediately, the first metamorphosis starts. by the ingestion, the mature male and female gametocytes, namely micro-and macrogametocytes, enter the mosquito host. immediately after reaching the mosquito's midgut, the two types of gametocytes undergo dramatic metamorphoses. we must remember that such transformations are a response to environmental stimulation, like a decrease in temperature, an increase in ph, and an influence of xanthurenic acid. within 10-20 min, the rounded macrogametes leave the erythrocytes and diffuse inside the blood, together with the flagellates microgametes. now comes the last change. within the next 24 h, the motile male gametes can fecundate the macrogametes, and round zygotes develop that mature to elongated motile ookinets and move to the outer midgut surface, completing early sporogonic development. these changes can be obtained by severe transformation inside the intrinsic cell organization, involving the cytoskeleton directly. an equatorial position of chromosomes in the metaphase plate in the middle of the spindle is necessary for mitosis and symmetric cell divisions. a symmetric metaphase plate position is essential for symmetric cell divisions, explaining why it is conserved in all metazoans, plants, and many fungi. control of this parameter is essential, since differences in cell size have been linked to cell fate and generate a class of anticancer drugs. movements of chromosomes are in charge of microtubules, which are elements of the cytoskeleton. the cytoskeleton is a network of protein fibers forming the "infrastructure" of eukaryotic and prokaryotic cells. in eukaryotic cells, protein filaments and motor proteins form a complex mesh of protein filaments and motor proteins. the cytoskeleton aids the inside cell movement and transportation of subunits, like organelles and molecule groups, stabilizes and maintains cell shape, and gives support and order. the cytoskeleton is not a static structure but it is able to disassemble and reassemble its parts in order to enable internal and overall cell mobility. intracellular movements include in particular manipulation of chromosomes during mitosis and meiosis from the equatorial plaque to the polar positions, in the formation of daughter cells, and also it is implicated in the immune cell response to pathogens. the cytoskeleton is composed of at least three different types of fibers: microtubules, microfilaments, and intermediate filaments. these fibers are distinguished by their size, with microtubules being the thickest and microfilaments being the thinnest. the assemblement of the proteins, tubulines a and b, makes microtubules, in form of long cave filaments. these hollow rods function primarily to help support and shape the cell and as "routes" along which organelles can move. therefore, without the action of microtubules, the cell is unable to reproduce. the cell is blocked in a limb, with part of the mitosis already done and the final act in progress. the result is a polyploid cell, meaning a cell with double or more than the normal number of chromosomes. because chromosomes cannot move alone, they must be dragged by the cytoskeleton. the mechanisms of action of several important antitumoral drugs derived from natural products are characterized by promotion of the assembly or disassembly of microtubules, meaning stabilization or destabilization of the tubules against depolymerization, resulting in mitotic arrest. treated cells have defects in mitotic spindle assembly, chromosome segregation and movements, and consequently in cell division. the main problem of the utilization of these compounds in combination chemotherapy for sensitive tumor types concerns their selectivity against malignant cells. cancer is basically a disease of uncontrolled cell division, including too-active mitosis, multiplying the cancerous mass. in most cases, these changes in activity are due to mutations in the genes that encode cell cycle regulator proteins. however, although cancer cells are a selected target, in consideration of their high level of mitosis, other tissues can be involved in the action of positive regulators of cell division. molecular agents of plant origin are of primary importance in cancer treatment. those acting on the cytoskeleton can be classified into two main groups: antimicrotubule agents like colchicine and the vinca alkaloids, which induce depolymerization of microtubules, and taxol and taxotere, which induce tubulin polymerization and form extremely stable and nonfunctional microtubules (rowinsky et al., 1990) . neem products have been seriously explored in recent years, in several sectors, mainly in the fight against insect-borne diseases. however, it seems that so far the potentiality of neem has been only lightly touched on. neemazal is a marketed neem product consisting of a quantified alcoholic extract obtained from azadirachta indica seeds, with a reported limonoid concentration of 57.7%, consisting of azadirachtin a 34%, azadirachtins b-k 17.7%, salanins 4%, and nimbins 2% (dembo et al., 2015; habluetzel et al., 2007) . neemazal completely blocks transmission of the rodent malaria parasite p. berghei to anopheles stephensii in vivo, when administered to gametocytemic mice at a corresponding azadirachtin a dose of 50 mg/kg. other in vivo transmission blocking studies suggested that na may have stronger transmission blocking activity than azadirachtin a alone, evaluating the activity of nonazadirachtin a constituents of neemazal. in an ex vivo assay, which exploits a major target process of azadirachtin a against p. berghei, microgamete formation inhibition of plasmodium was used to estimate the pharmacodynamics of two varying doses of neemazal and azadirachtin a. a team led by prof. g. chianese (university of salerno, italy) explored the possibility of influencing plasmodium gametocytes by neem products, demonstrating the potential of blocking the reproduction stages of the parasite. neemazal is a marketed neem product consisting in a quantified alcoholic extract obtained from azadirachta indica seeds, with a reported limonoid concentration of 57.7%, consisting in azadirachtin a 34%, azadirachtins b-k 17.7%, salanins 4%, and nimbins 2%. neemazal completely blocks transmission of the rodent malaria parasite p. berghei to anopheles stephensii in vivo, when administered to gametocytemic mice at a corresponding azadirachtin a dose of 50 mg/kg. other in vivo transmission blocking studies suggested that na may have stronger transmission blocking activity than azadirachtin a alone, evaluating the activity of nonazadirachtin a constituents of neemazal. azadirachtins exert relevant effects on microtubules assembly and organization, interfering with the expression and/or function of adhesive proteins during the genesis of microgametocytes, through disruption of the organization of mitotic spindles and cytoskeleton formation and activity. these molecules can interfere with cytoplasmic microtubule organization and distribution, causing severe depletion of actin levels. in this action, neemazal proved to be more effective than azadirachtin a. in confirmation, another study showed that the product completely inhibits the growth of p. falciparum field isolates in an. coluzzii mosquitoes at a dose of 70 ppm in direct membrane feeding assays. microorganisms have not finished producing surprises and breaking the boundaries reported in books. meanwhile researchers are investigating malaria parasites more and more deeply in search of their weak points, but their study is complicated by the parasite's metamorphosis, which involves not only the shape but also fundamental aspects of the metabolism (becker and kirk, 2004) . asexual stages of the parasite contain a single mitochondrion, whereas gametocytes can have several mitochondria. the energy production is very important. plasmodium falciparum, as well as other similar apocomplexa protozoans, possesses an intriguing nonphotosynthetic plastic, discovered in the 1970s. the surprise was that apicoplastides possess their own nucleic acid. regarding their role, they were considered by kilejian (1991) as "a source of some substrate essential for energy production of mitochondrion." in view of their other characteristics, they could be considered a possible bridge between organisms or the ancestral point of divergence from green algae and protozoans. in conclusion, apicoplastides could be part of the endosymbiosis pathway, wherein degenerated chloroplasts were useful to increase a mitochondrial efficiency still in evolution. thus, endosymbiosis started with the inclusion of the two main bacterial forms, the hetero-and the autotrophic one, but later the ancestral (green or red) primordial alga degenerated the chloroplast in favor of a clear evolution toward the heterotrophic metabolism ( fig. 7.23) . usually the shift to the eukaryotic cell is considered a consequence of environmental factors, such as the increase of oxygen in the oxidative atmosphere; however, it is possible that in some cases interactions between organisms could also have played an important role. the study on apicoplastides allowed researchers to evidence similarities (keeling, 2008; kilejian, 1975; k€ ohler et al., 1997) between different arthropod-borne diseases, such as avian malaria, eimoriosis, and toxoplasmosis, confirming once more the occurrence of common survival strategies in different organisms. other differences concern the enzymes network and the membrane transport mechanisms. the new knowledge about parasitespecific organelles could be of fundamental importance to the development of future antimalarial drugs, increasing efficiency and decreasing side effects, like resistance. another important research front full of possibilities is focused on the membrane mechanism of cq's extrusion by permeability pathways induced by the parasite in the host red blood cells (saliba et al., 1998) . this is related to the cq of interfering with the detoxification of toxic heme monomers. the studies showed that 12-16 h after the invasion by the parasite, the socalled new permeability pathways act on the interchanges, i.e., the entry of nutrients, as well as mediating the efflux of metabolic wastes. several groups advanced the hypothesis of a number of channel types, activated by particular stress or stimuli (ginsburg and stein, 2004; kirk et al., 1994; duranton et al., 2004; staines et al., 2004; thomas and lew, 2004) . all these references testify to and confirm the presence of a wide range of studies in search of an answer to the challenge of resistance. the front is still too large and undetermined, but every year the knowledge of host cell reaction is increasing and there is a high probability that the problem will be solved in the coming years. during the development of the arguments contained in this book, it was necessary link the insect-borne diseases argument to several collateral items. the idea in particular was concentrated on a possible utilization of this particular topic as an epiphany, meaning an enlightening subject, which allows a revision of the problem from a new perspective. the interpretation of a new and key piece of information can allow the process of significant thought about a problem, until, in accordance with the original significance of the term in ancient greek, the ἐπιφάνεια (epiphanea) appears like a manifestation, with a striking appearance. this book started with considerations about gaps and books. let us now return to these two points. the lesson from carson's book about the fundamental role of beneficial insects in the survival of mankind, has arguably not been understood. throughout all warm terrestrial ecosystems, insects are a dominant component and they are part of the lives of any organism. the insect-plant relationship is a fundamental biotic interaction, and plants account for a large part of the planet's biomass, many times the biomass of all animals together (new, 2002; jankielson, 2018; dunn, 2005) . the animal biodiversity is dominated by that of insects. they are a beautiful example of variability, in terms of both number of species (more than 1 million) and abundance (more than half of all living organisms), although at most only about 7%-10% of insects are scientifically described. this diversity, consisting of large numbers of individuals and great intra-and interspecific variety, is a consequence of the enormous functional significance of insects in habitats. primitive insects appeared very early in the silurian period, when plants and animals finally emerged from the sea and colonized dry land, and over the last 400 million years the number of insect families has been rising. they were able to colonize any part of the territory, including the sky. today, the number of reported insect families is about 600 and they have survived various negative major impacts, including the mass extinction event at the end of the cretaceous period. a review analysis, published in the journal biological conservation by francisco sánchez-bayo, at the university of sydney, australia, and kris wyckhuys, at the china academy of agricultural sciences, beijing china, attests a current insect collapse. the decline's hypothesis is based on a study of 73 recent selected studies. the causes and significant factors include intensive agriculture, the heavy use of pesticides, urbanization, and climate change. the loss of insect population is calculated in an annual 2.5% rate over the last 20-25 years, and the future tendency is evaluated to 25% in the next 10 years and increasing continuously until only half left in 100 years. this scenario is already underway. in puerto rico, a recent study revealed a 98% fall in ground insects over 35 years. the catastrophic cascade effects on the planet's ecosystems include ants, aphids, shield bugs, and crickets, which are the food for many birds, reptiles, amphibians, and fish that eat insects. there are many indicators supporting the scenario (sánchez-bayo and wyckhuys, 2019; diamond, 1989) . in england, between 2000 and 2009, the number of widespread butterfly species fell by 58% on farmed land, suffering the biggest recorded insect falls overall-though that is probably a result of this area being more intensely studied than most places. a particular alert concerning bees being seriously affected has also been raised in europe and the usa; for example, only half of the bumblebee species found in oklahoma in the usa in 1949 were present in 2013 (alburaki et al., 2015 (alburaki et al., , 2018 aizen, 2009 ). the number of honeybee colonies in the usa was 6 million in 1947, but 3.5 million have since been lost. in 2013, according to eu data, there were around 630,000 beekeepers and 16 million hives in the eu, producing 234,000 tons of honey per year, but the same source tells us that many insect pollinator populations are now in clear decline. there is similar news from brazil, with half a million bees dead. on one side, this is considered the effect of the use of some pesticides, toxic to bees. on the other side, it is a classic example of rapid and intense environmental change to improve agricultural intensification and pasture, with the systematic elimination of all trees and shrubs that normally surround the fields, so there are plain, bare fields that are treated with synthetic fertilizers and pesticides. dr. sanchez-bayo said: "we are not alarmists, we are realists. we are experiencing the sixth mass extinction on earth. if we destroy the basis of the ecosystem, which are the insects, then we destroy all the other animals that rely on them for a food source." he added, "it will collapse altogether and that's why we think it's not dramatic, it's a reality." the situation comprehends micro-and macroepisodes, like the continuous devastation of equatorial tropical forests, in particular the amazonia territory. the sequence is clear and well-known, and it always works: first, the fire destroys the vegetation, in particular the woody plants; second, the soil is cleaned, otherwise the plants could replace the habitat rapidly; and third, the territory is declared totally compromised and ready for further utilizations. however, as observed by samways in biodiversity and conservation (1993, and later confirmed by this author in a series of further papers) in a paper titled "insects in biodiversity conservation: some perspectives and directives," the main concerns are the "lack of human appreciation of importance, coupled with the general disregard and dislike of insects, is an enormous perception impediment to their conservation. this impediment coupled with the taxonomic impediment must be overcome for realistic biodiversity conservation management. as it is not possible to know all the species relative to the rate at which they are becoming extinct, it is essential to conserve as many biotopes and landscapes as possible." there is a sentiment of urgency for measures "essential to preserve species dynamo areas as an insurance for future biodiversity," such that "preserved areas must also be linked by movement and gene-flow corridors as much as possible." the last point of view is crucial. preservation must be considered not only as an opportunity to maintain the presence of species in selected habitats against their disappearance, but it must be considered changes as opportunities to perform a positive future. in this regard, entomologists are asked to contribute in control of vectors affecting humans, crops, and livestock, but also to take an active part in the consideration due to the beneficial species. the central task is the possibility to predict accurately the environmental effects of any intervention. once the inherent risks connected with traditional control methods have been considered, the consequences of new introductions must be carefully predicted, including any synergist effect. the rate of insect species extinction is estimated as being eight times faster than those of mammals, birds, and reptiles (barnosky et al., 2011; dirzo et al., 2014) . another important current gap concerns scientific information. most ordinary people do not have access to data obtained by the scientific community, as well as opinions and models produced by experts and scientists. information, when available, is usually distorted and adapted to the dominant axioms by a plethora of generalist supposed experts. the proposed idea is that these kinds of people are able to know and comment on everything. the distortion, sometimes voluntarily pursued and often a consequence of general confusion, generates progressive modification of the starting points and even the concealment of important facts. the recent phenomenon of fake news is clearly generated from the same situation. although most research information is now easily accessible and can be obtained directly from the internet, its utilization remains restricted to dedicated people. in contrast, some scientific information is amplified far away from its real impact. how many times did you read about the discovery of a definitive cure to cancer? or about the already obtained solution to any physiological problem using staminal cells? in our era of globalized knowledge, news are obtained and fluxed indirectly, without few possibility of checking the origin and the reliability. it is necessary to consider that more than 46% of the human population, consisting of 3.5 billion people, are connected via the internet, and 2.5 billion utilize social networks regularly. these numbers are likely to increase 10% every year. all these people have access to information only through selected channels and although they are in a condition to verify it, science and general information are on different and distant levels. the main problem is that the information is reduced to a few soundbites, and there is no place for elaboration or proposals of other possible interpretations or points of view. this is not a recent case, produced by digitalization of communication. beside the sources, the problem of the quality of scientific information was fully evidenced more than 30 years ago, in the "public understanding of science." this is the title of a report requested in 1985 by the royal society and prepared by a group of experts, whose leader was the geneticist sir walter fred bodmer. the report evidenced the general lack of knowledge about scientific themes. on one side, most of the population, accounting for two-thirds of europeans, was confident about science and technologies, considering that scientists were able to solve human problems and make human life "easier, healthier and comfortable." on the other side, the sequence "more communication ¼more knowledge¼more social adherence to scientific arguments" appears largely inadequate. the dominant problem about scientific communication is that ordinary people need an alphabetization to understand and meet the complexity of the scientific items. the conversion of the original scientific information is usually distorted and changed, at best "adapted," but more often polluted by political, social, and cultural interests. the result is a reductive metamorphosis, in the best case, or complete revision to be adapted and useful to already-made opinions. among the various examples of this operation we find neverending debates, such as those concerning ogm, vaccines, or the consequences of climate changes, without considering abnormal and artificially created themes, such as the contraposition between vegans and meat-eaters. the manipulation is based on a presumed "democratic" interpretation of scientific data. no vote is necessary to assure the consistency of a scientific law based on adequate experimentation, but the aim is that reliability must be obtained by public consensus and even agreement. independence has always been a necessary character of science, but manipulation was never pursued. history tells us that any political or social manipulation of science led to disaster. in contrast, priorities, when based on correct scientific information, as well as consequent implications and decisions, must be subject to the most ample democracy. at the end of this little journey through macro-, micro-, and nanoworlds, it is undeniable how long the road still is to understand and discover the mysteries of insect-borne diseases. in the meantime, we await the next surprises. the covid-19 pandemy dramatically evidenced all the current limits of science and technology to face this kind of challenges. the virus was faster and clever. predictively and prevention were insufficient. despite the potentiality, the debacle and medicine was evident and the consequent economic and social damages were enormous. microorganisms will continue to play their role inside the habitats and next time their target could be the industrialized sources of our food. however, it is clear that is society will continue to ignore the alerts of researchers and scientists, the next pandemy will be the worst one. synergy between two calcium channel blockers, verapamil and fantofarone (sr33557), in reversing chloroquine resistance in plasmodium falciparum active and intelligent packaging: an introduction how much does agriculture depend on pollinators? lessons from long-term trends in crop production neonicotinoid-coated zea mays seeds indirectly affect honeybee performance and pathogen susceptibility in field trials honey bee survival and pathogen prevalence: from the perspective of landscape and exposure to pesticides green-synthesised nanoparticles from melia azedarach seeds and the cyclopoid crustacean cyclops vernalis: an eco-friendly route to control the malaria vector anopheles stephensi? operational feasibility of malaria control by burning neem oil in kerosene lamp in beel akbarpur village, district ghaziabad, india review of antimicrobial food packaging evaluation of larvicidal activity of medicinal plant extracts against three mosquito vectors has the earth's sixth mass extinction already arrived? antibacterial activity of karanj (pongamia pinnata) and neem (azadirachta indica) seed oil: a preliminary report of malaria, metabolism and membrane transport old ingredients for a new recipe? neem cake, a low-cost botanical by-product in the fight against mosquito-borne diseases larvicidal and ovideterrent properties of neem oil and fractions against the filariasis vector aedes albopictus (diptera: culicidae): a bioactivity survey across production sites shedding light on bioactivity of botanical by-products: neem cake compounds deter oviposition of the arbovirus vector aedes albopictus (diptera: culicidae) in the field neem (azadirachta indica): towards the ideal insecticide? synergized mixtures of apiaceae essential oils and related plantborne compounds: larvicidal effectiveness on the filariasis vector culex quinquefasciatus say chemical composition and insecticidal activity of the essential oil from helichrysum faradifani endemic to madagascar ethnopharmacology in the fight against plasmodium parasites and brain disorders: in memoriam of philippe rasoanaivo insecticidal and mosquito repellent efficacy of the essential oils from stem bark and wood of hazomalania voyronii herbal remedies of azadirachta indica and its medicinal application biological activities and medicinal properties of neem (azadirachta indica) le paludisme à madagascar a guide to the identification of diseases and pests of neem (azadirachta indica). rap publ neem-an omnipotent plant: a retrospection responsive food packaging: recent progress and technological prospects insecticide resistance in mosquitoes: a pragmatic review natural products as sources for new pesticides emergency and mosquitocidal potential of neem cake-synthesized silver nanoparticles: genotoxicity and impact on predation efficiency of mosquito natural enemies the efficacy of neem extract on four microorganisms responsible for causing dental caries viz streptococcus mutans, streptococcus salivarius, streptococcus mitis and streptococcus sanguis: an in vitro study biological activities and medicinal properties of neem (azadirachta indica) a novel phytocannabinoid isolated from cannabis sativa l. with an in vivo cannabimimetic activity higher than δ 9 -tetrahydrocannabinol: δ 9 bioactive packaging technologies for extended shelf life of meat-based products effectiveness of antimicrobial food packaging materials in vitro and ex vivo activity of an azadirachta indica a. juss seed kernel extract on early sporogonic development of plasmidium in comparison with azadirachtin a, its most abundant constituent active and intelligent packaging: applications and regulatory aspects assessment of neem oil effect on haematological profile and towards peripheral blood mononuclear cells of goat antimicrobial activity of a neem cake extract in a broth model meat system evaluation of a mono-component and a multicomponent herbal extracts as candidates for antimicrobial packaging of fresh retail meat assessment of microbiological quality of retail fresh pork meat in central italy neem (azadirachta indica a. juss) oil to tackle enteropathogenic escherichia coli impact of repeated neemazal ® treated blood meals on the fitness of anopheles stephensi mosquitoes the present, past and future of human-caused extinctions defaunation in the anthropocene active and intelligent packaging food-research and development-a review modern insect extinctions, the neglected majority organic osmolyte permeabilities of the malaria-induced anion conductances in human erythrocytes successful parasitoid control of aonidiella orientalis (newstead) (hemiptera: diaspididae) on carica papaya l biopesticide registration action document. office of pesticide programs. cold pressed neem oil. pc code 025006. margosa extract pt-18 secondary metabolism as a measurement of the efficacy of botanical extracts: the use of azadirachta indica (neem) as a model insecticide status report on global neem usage indole alkaloids from strychnos species and their antiplasmodial and cytotoxic activities inherited glutathione reductase deficiency and plasmodium falciparum malaria-a case study plant extracts as potential mosquito larvicides phytochemicals for bacterial resistance-strengths, weaknesses and opportunities the new permeability pathways induced by the malaria parasite in the membrane of the infected erythrocyte: comparison of results using different experimental techniques neem-a green treasure chemical and biological investigations on azadirachta indica (the neem tree) plants myths and traditions in india impact of the botanical insecticide neem azal ® on survival and reproduction of the biting louse damalinia limbata on angora goats food losses and waste in the context of sustainable food systems neem pesticides the importance of insect in agricultural ecosystems focus on phytochemical pesticides. the neem tree increasing food availability by reducing postharvest losses of fresh produce chemische untersuchungen € uber die metamorphosehormone der insekten neemdb: convenient database for neem secondary metabolites bridge over troublesome plastids past, current and potential utilization of active and intelligent packaging systems for meat and muscle-based products: a review circular mitochondrial dna from the avian malarial parasite plasmodium lophurae spherical bodies transport of diverse substrates into malariainfected erythrocytes via a pathway showing functional characteristics of a chloride channel a plastid of probable green algal origin in apicomplexan parasites malagashanine: a chloroquine potentiating indole alkaloid with unusual stereochemistry neem: today and in the new millennium neem (azadirachta indica): prehistory to contemporary medicinal uses to humankind neem in the conventional lake chad basin area and the threat of oriental yellow scale insect (aonidiella orientalis newstead) (homoptera: diaspididae) current topics in active and intelligent food packaging for preservation of fresh foods not ordinary antimalarial drugs: madagascar plant decoctions potentiating the chloroquine action against plasmodium parasites glutathione transferase from plasmodium falciparum-interaction with malagashanine and selected plant natural products antimicrobial food packaging: potential and pitfalls citrus limonoids: analysis, bioactivity, and biomedical prospects antilarval activity of neem cake extracts against aedes albopictus composizione biologica con proprietà fortemente biocide a basso contenuto di azadiractina e procedimento per la sua realizzazione antimicrobial activity of melia azadirachta fruit extracts for control of bacteria in inoculated in vitro shoots of 'mrs-2/5' plum hybrid and calla lily and extract influence on the shoot cultures reversal of chloroquine resistance in plasmodium falciparum by verapamil verapamil reversal of chloroquine resistance in the malaria parasite plasmodium falciparum is specific for resistant parasites and independent of the weak base effect product safety and security in the global supply chain: issues, challenges and research opportunities effect of neem leaf extract and on penicillum growth, sporulation, morphology and ochratoxin a production mosquitocidal and antiplasmodial activity of senna occidentalis (cassiae) and ocimum basilicum (lamiaceae) from maruthamalai hills against anopheles stephensi and plasmodium falciparum in vivo and in vitro effectiveness of azadirachta indica-synthesized silver nanocrystals against plasmodium berghei and plasmodium falciparum, and their potential against malaria mosquitoes report of an ad hoc panel of the board on science and technology for international development natural products as sources of new drugs from 1981 to hptlc fingerprint: a modern approach for the analytical determination of botanicals traceability in multi-ingredient botanicals by hptlc fingerprint approach advances in production of functional foods and nutraceuticals advanced in production of functional foods and nutraceuticals intelligent and smart packaging hptlc fingerprint analysis of plant staminal products analysis of multi-ingredient food supplements by fingerprint hptlc approach toxic effects of neem cake extracts on aedes albopictus (skuse) larvae neem cake: chemical composition and larvicidal activity on asian tiger mosquito the modern analytical determination of botanicals and similar novel natural products by the hptlc fingerprint approach current mosquito-borne disease emergencies in italy and climate changes. the neem opportunity neem-borne molecules as eco-friendly control tools against mosquito vectors of economic importance professor philippe rasoanaivo neem tree-"the village pharmacy the control of the oriental red scale, aonidiella orientalis newstead and the california red scale, a. aurantii (maskell) (homoptera: diaspididae) in mango orchards in hevel habsor (israel) trends in antimicrobial food packaging systems: emitting sachets and absorbent pads active food packaging technologies use of natural antimicrobials to increase antibiotic susceptibility of drug resistant bacteria glutathione biosynthesis and metabolism in plasmodium falciparum traditional herbal remedies and dietary spices from cameroon as novel sources of larvicides against filariasis mosquitoes? chemical composition of cinnamosma madagascariensis (cannelaceae) essential oil and its larvicidal potential against the filariasis vector culex quinquefasciatus say the interaction of heme with plakotin and a synthetic endoperoxide analogue: new insights into the heme-activated antimalarial mechamism neem: the divine tree azadirachta indica reversal activity of the naturally occurring chemosensitizer malagashanine in plasmodium malaria tetranortriterpenoids from azadirachta indica effect of the leaf essential oil from cinnamosma madagascariensis danguy on pentylenetetrazol-induced seizure in rats biological activities of the plant-derived bisindole voacamine with reference to malaria malagashanine potentiates chloroquine antimalarial activity in drug resistant plasmodium malaria by modifying both its efflux and influx malagashanine and malagashine, the alkaloids of strychnos mostuoides medicinal plants used to treat malaria in madagascar revised structure of malagashanine: a new nb,c(21)-secocuran alkaloid reversing agents in treatment of drug-resistance malaria the co-occurrence of c(3) epimer nb,c(21)-secocuran alkaloids in strychnos diplotricha and strychnos myrtoides screening extracts of madagascan plants in search of antiplasmodial compounds taxol: a novel investigational antimicrotubule agent limonoids: overview of significant bioactive triterpenes distributed in plants kingdom neem, a tree for solving global problems anti-microbial activity of a new vaginal contraceptive nim-76 from neem oil (azadirachta indica) transport and metabolism of the essential vitamin pantothenic acid in human erythrocytes infected with the malaria parasite plasmodium falciparum insects in biodiversity conservation: some perspectives and directives worldwide decline of the entomofauna: a review of its drivers fatty acid composition and antibacterial activity of neem (azadirachta indica) seed oil sustainable industrial utilization of neem tree (azadirachta indica) in nigeria some arthropod pests and a semi-parasitic plant attacking neem (azadirachta indica) in kenya the neem tree: azadirachta indica a. juss. and other meliaceous plants, sources of unique natural products for integrated pest management, medicine, industry and other purposes the neem tree: source of unique natural products for integrated pest management, medicine, industry and other purposes the neem tree (azadirachta indica a. juss) and other meliaceous plants: sources of unique natural products for integrated pest management a review of botanical phytochemicals with mosquitocidal potential mosquito repellent action of neem (azadirachta indica) oil quality of packaged foods plasmodium falciparum-induced channels ethnobotanical uses of neem (azadirachta indica a. juss.; meliaceae) leaves in bali (indonesia) and the indian subcontinent in relation with historical background and phytochemical properties the role of botanicals as green pesticides in integrate mosquito management-review monograph on neem (azadirachta indica a. juss.). international book distributors biosensors in food processing plasmodium falciparum and the permeation pathway of the host red blood cell susceptibility of immature stages of aedes aegypti, the vector of dengue and chikungunya to insecticides from india neem (azadirachta indica) and its potential for safeguarding animals and humans the hptlc approach to metabolomic determination of neem products composition determination by hptlc of chemical composition variability in raw material used in botanicals costa concordia disaster: environmental impact from phytochemical point of view trasmission blocking effects of neem (azadiracha indica) seed kernel limonoids on plasmodium berghei sporogonic development ecophysiological and phytochemical response to ozone of wine grape cultivars of vitis vinifera ethnopharmacognostical survey of azadirachta indica a juss quassinoids: structural diversity, biological activity and synthetic studies public health impact of pesticides used in agriculture: reportage of a world health organization and u.n. environmental programme malaria treatment guidelines. world health organization key: cord-277802-f8pyn3rx authors: roman, gheorghe title: mannich bases in medicinal chemistry and drug design date: 2015-01-07 journal: eur j med chem doi: 10.1016/j.ejmech.2014.10.076 sha: doc_id: 277802 cord_uid: f8pyn3rx the biological activity of mannich bases, a structurally heterogeneous class of chemical compounds that are generated from various substrates through the introduction of an aminomethyl function by means of the mannich reaction, is surveyed, with emphasis on the relationship between structure and biological activity. the review covers extensively the literature reports that have disclosed mannich bases as anticancer and cytotoxic agents, or compounds with potential antibacterial and antifungal activity in the last decade. the most relevant studies on the activity of mannich bases as antimycobacterial agents, antimalarials, or antiviral candidates have been included as well. the review contains also a thorough coverage of anticonvulsant, anti-inflammatory, analgesic and antioxidant activities of mannich bases. in addition, several minor biological activities of mannich bases, such as their ability to regulate blood pressure or inhibit platelet aggregation, their antiparasitic and anti-ulcer effects, as well as their use as agents for the treatment of mental disorders have been presented. the review gives in the end a brief overview of the potential of mannich bases as inhibitors of various enzymes or ligands for several receptors. the classical mannich reaction, a three-component condensation between structurally diverse substrates (xeh) containing at least one active hydrogen atom, an aldehyde component (generally r 1 -cho) and an amine reagent leads to a class of compounds generally known as mannich bases 1 (scheme 1). because mannich bases may be regarded as derivatives of the substrate obtained through substitution by an aminoalkyl moiety, mannich reactions are also known as aminoalkylation reactions. in the particular instance when formaldehyde is employed as aldehyde component, the substrate is converted into the corresponding mannich base through an aminomethylation process. although primary amines and even ammonia (in the form of an ammonium salt) may be employed as amine reagents in aminomethylations or aminoalkylations, secondary aliphatic amines (r 2 nh) are the most commonly encountered as amine reagents in the mannich reaction. as formaldehyde is used to a great extent as aldehyde component in the mannich reaction, the structural diversity of mannich bases stems primarily from the miscellaneous types of the substrates that can be subjected to aminomethylation, and secondarily from the variety of amine reagents that can be potentially employed in the mannich reaction. regardless of their structural diversity, the substrates should all have an activating functional group as a crucial structural feature that is required to render the substrate active in the mannich reaction. the carbonyl function in ketones, the phenolic hydroxyl in phenols, the terminal carbonecarbon triple bond in alkynes, the heteroatom in heterocycles, or electronwithdrawing groups that substitute the carbon atom a to the carboxylate group in esters of aliphatic carboxylic acids are common examples of pairs of activating groups and corresponding substrates, but the list is far from being exhaustive. a general classification of the most common types of mannich bases with respect of the substrates from which they derive and the nature of the atom substituted by the aminomethyl function is given in fig. 1 . under normal reaction conditions, substitution of a substrate with a single aminomethyl function results in mono-mannich bases, but two aminomethyl groups may also be grafted onto a substrate containing more than one active hydrogen atom, leading to double mannich bases such as 2e5 derived from dialkyl ketones, alkyl aryl ketones, 4-substituted phenols and pyrrole, respectively (fig. 2) . also, the aminomethylation of substrate xeh with amine reagents other than secondary amines (such as ammonia, having three reactive hydrogen atoms at nitrogen, or primary amines renh 2 , having two reactive hydrogen atoms at nitrogen) may lead to tris-mannich bases 6 and bis-mannich bases 7, respectively (fig. 2 ). in addition, the capability of some polyfunctional substrates to aminomethylate chemoselectively at a single potential reaction site under the appropriate reaction condition, or aminomethylate indiscriminately at multiple reaction sites, or even undergo aminomethylation simultaneously with ring closure, contributes considerably to the structural variety of the resulting mannich bases. two excellent, albeit rather old reviews provide more details on the synthesis and reactions of mannich bases to the interested reader [1, 2] . mannich bases have found numerous practical applications in the treatment of natural macromolecular materials such as leather, paper and textiles, the production of synthetic polymers, as additives used by the petroleum industry, as products used in water treatment, analytical reagents, cosmetics, dyes, etc. [3] . nonetheless, the most important application of the mannich reaction lies in the field of medicinal chemistry, and this claim is supported by the substantial number of papers published on this topic every year. first of all, mannich bases could present interesting biological activities, many of these having yet to be discovered through a diligent screening process. second, aminomethylation of drugs could be used to improve their delivery into the human body. aminomethylation may increase the hydrophilic properties of drugs through the introduction of a polar function in their structure, the long-known rolicycline being one of the most common examples [4] . the solubility in water of a drug could be further enhanced through the quaternization of the nitrogen atom in its aminomethyl derivative and conversion into an ammonium salt. alternatively, the lipophilic properties of a drug could be tailored through a mannich reaction if the appropriate amine reagent is employed [5] . in addition, the aminomethylated drugs could act as prodrugs, releasing the active substance under controlled hydrolytic conditions via deaminomethylation [6] or deamination [7] . in spite of the tremendous potential of mannich bases in medicinal chemistry, the wealth of information from studies concerning the structureeactivity relationship (sar) involving mannich bases or the use of aminomethylated drugs as prodrugs does not appear to have inspired many recent literature reviews of consequence, to the best of our knowledge. the present review fills this void by providing a comprehensive coverage of the most relevant developments in the medicinal chemistry of mannich bases generated exclusively through aminomethylation, the information being ordered according to the reported biological activity. due the large number of articles published on this topic, the coverage of this review is limited to the last decade. anticancer properties and cytotoxicity of ketonic mannich bases (with an emphasis on mannich bases of type 8 derived from acetophenones [8] ) and of structurally related a,b-unsaturated ketones [9] were reviewed 15 years ago. these two groups of compounds were shown to exert their cytotoxic action through the alkylation of cellular thiols such as glutathione or cysteine, and may be useful in sensitizing tumor cells to antineoplastic agents, and even reverse drug resistance [10] . it is therefore no surprise that compounds having both a ketonic mannich base moiety and an activated unsaturated carbonecarbon double bond in their structure (for example, mannich bases of chalcones such as 9) have been considered as candidates for the evaluation of the sequential cytotoxicity theory [11] . this theory hypothesizes that the successive release of two or more cytotoxic agents will result in increased toxicity to malignant tissue rather than to normal cells [12] . in addition, mannich bases 10 of enones, which are easily accessible from alkyl aryl ketones in one synthetic step, also demonstrated marked toxicity towards numerous cancer cell lines [13] . furthermore, as ortho-phenolic mannich bases undergo deamination easily to yield ortho-quinone methides, mannich bases of chalcones derived from either phenolic aldehydes or ketones, a class of compounds for which structure 11 is prototypical, have been examined also as cytotoxic agents [14] . in the last decade, the quest for more potent anticancer agents amongst these four general types of cytotoxic mannich bases 8e11 (fig. 3 ) has steadily continued. cytotoxicity of ketonic mannich bases of type 8 with various substitution patterns in the aromatic ring and of a few types of their derivatives has been studied in detail. gul et al. have shown that the structural modification of single mannich bases 8 (r 1 ¼ r 2 ¼ h) derived from acetophenone and secondary aliphatic amines into double mannich bases 12 (fig. 4) generally results in increased cytotoxicity against mouse renal carcinoma (renca) and transformed human t-lymphocyte (jurkat) cell lines [15] to the extent that double mannich bases were more cytotoxic than reference drugs 5-fluorouracil or melphalan. the cytotoxicity of these single and double mannich bases 8 and 12, respectively, was reversed when the compounds were used in a brine shrimp bioassay, presumably due to the fast deamination of the double mannich bases before they could reach their target [16] . also, ketonic mannich bases 8 with dimethylamino, 1-piperidinyl, 4-morpholinyl as amine moiety and featuring either an unsubstituted, variously monosubstituted phenyl rings, or a thiophene ring were evaluated with respect of their cytotoxicity towards jurkat cells [17, 18] or androgen-independent prostate cancer (pc-3) cells [19] , and the cytotoxicity for some of these compounds was 2.5-to 5.2-fold higher than that of the standard 5-fluorouracil. in addition, mannich bases of type 8 derived from 4-aryloxyacetophenones were shown to display moderate cytotoxic properties towards murine l1210 cells as well as human molt 4/c8 and cem t-lymphocytes, and a number of these compounds possessed remarkable potencies towards seven human colon cancer cell lines [20] . the use of primary aliphatic amines in the mannich reaction leads to reaction products with diverse structures (fig. 4) . aminomethylation of acetophenones using methylamine as amine reagent afforded both bis-mannich bases 13 (r ¼ ch 3 ) and piperidinols 14 (r ¼ ch 3 ) , and the evaluation of their cytotoxicity towards jurkat cells showed that bis-mannich bases 13 were generally more potent than the corresponding piperidinols 14 or mono-mannich bases 8 [21] . besides their ability to alkylate cellular glutathione, compounds 13 (r ¼ ch 3 ) may exert their cytotoxic action through the inhibition of dna topoisomerase i; as the corresponding piperidinols 14 were generally devoid of dna topoisomerase i inhibitory action, the authors tentatively attribute the activity of bis-mannich bases 13 to their linear structure and the possibility of formation of hydrogen bonds with dna nucleotides [22] . on the other hand, aminomethylation of acetophenones using isopropylamine [23] and n-butylamine [24] as amine reagent yielded only secondary mono-mannich bases 15 (r ¼ ch(ch 3 ) 2 , (ch 2 ) 3 ch 3 ), whose cytotoxicity was evaluated against huh-7 hepatoma cells, human jurkat and rat skeletal muscle derived myoblasts (l6) cells. compared to reference drug 5-fluorouracil, these compounds were 2.1-to 2.8-fold more cytotoxic towards huh-7 hepatoma cells, 2.6-to 4.2-fold more cytotoxic towards human jurkat cells, and 1.2-to 2.2-fold more cytotoxic towards l6 cells. aminomethylation of acetophenones using phenethylamine as amine reagent could led under carefully controlled reaction conditions either to mono-mannich bases 15 (r ¼ ch 2 ch 2 c 6 h 5 ) [25] or to the corresponding piperidinols 14 (r ¼ ch 2 ch 2 c 6 h 5 ) [26] ; the cytotoxicity of these compounds towards androgen-independent prostate cancer (pc-3) cells ranged from 8.2 to 32.1 mm, whereas the best compounds from each series had an average value for dna topoisomerase i interference of approximately 40%. anticancer activity of ketonic mannich bases has been compared with that of derivatives of the carbonyl function (fig. 4) . a series of azines 16 of ketonic mannich bases 8 were designed as bifunctional cytotoxic agents, but their activity towards jurkat cells [19] or pc-3 cells [17] was less potent or, in the best of cases, equipotent to the parent ketonic mannich bases. on the other hand, hydrazones 17 were consistently more cytotoxic than the corresponding ketonic mannich bases [18] . noteworthy is the contribution of gul et al. to the understanding of the mechanism of the cytotoxic action of these compounds. his group has provided evidence that connects the anticancer activity of ketonic mannich bases of various structures or piperidinols 14 with their ability to alkylate glutathione [21,27e29] , whereas a few of the same compounds had mixed effects on thioredoxin, glutaredoxin, or heat shock proteins hsc70 and grp75 [30] . only a limited number of examples of mannich bases of a,bunsaturated ketones of type 9 with cytotoxic action are available in recent publications. a small series of mannich bases 18 of 1arylidene-2-tetralones ( fig. 5) were evaluated as cytotoxic agents using human molt 4/c8 and cem t-lymphocytes, as well as murine p388 and l1210 leukemic cells [31] . compared to the parent a,bunsaturated ketones, mannich bases 18 were consistently more potent, with half maximal inhibitory concentration (ic 50 ) values in the 0.2e10 mm range. furthermore, mannich bases 18 derived from aromatic aldehydes substituted with chlorine, carboxyl, methoxy or cinnamoyloxy groups exhibited significant potencies towards human tumor cell lines, with an emphasis on their antileukemic effect. in most instances, the compounds prepared in this study demonstrated selective toxicity to different cells, which further enhances their potential utility. in addition to compounds 18, simpler mannich bases 19 derived from 2benzylidenecyclohexanones were synthesized, and their evaluation against the same cell lines proved once more that mannich bases were more cytotoxic than the corresponding 2arylidenecyclohexanones, some of them showing growthinhibiting properties (ic 50 of approximately 2 mm) more potent than reference drug melphalan [32] . because n-myristoyltransferase is expressed in larger quantities in tumors than it is in normal cells, this enzyme has been under consideration as a molecular target for cancer [33, 34] . however, the substantially high ic 50 value of 500 mm towards n-myristoyltransferase for a representative compound of the series of candidates 19 suggests that the inhibition of this enzyme does not play an important role in the mechanism of the cytotoxic activity of these compounds. several compounds 19 were also tested against murine cancer cells mac13 (sensitive to most cytotoxic agents) and mac16 (resistant to most cytotoxic agents), and they demonstrated high cytotoxicity against the latter, but also against normal murine cells c2c12 and 3t3 [35] . on the other hand, mannich bases 20 showed no activity against mac16, which points to the importance of the double bond conjugated to the carbonyl function. the exploration of possible mechanisms of cytotoxic action of these compounds revealed that compounds 19 may interfere with a number of essential cellular mechanisms by alkylation of thiols on enzyme or proteins, by disrupting mitochondrial electron transport, or by creating holes in the cell membrane, and thus promoting atp leakage [35] . finally, mannich bases 21 had high cytotoxic activity against two human breast cancer cell lines (mcf-7 and mcf-7/adr) cells and human leukemia hl-60 cells, showed glutathione binding ability, and exhibited inhibitory action on glutathione-s-transferase p, whereas their analogues obtained through the hydrogenation of the double carbonecarbon bond were slightly less active [36] . the nature of the dialkylamino group did not seem to affect the cytotoxic activity of these compounds, while the substitution of the aromatic rings with a methyl selectively increased the cytotoxic effect on breast cancer cells, but not on immortalized mammary epithelial (184b5) cells. the literature reporting the anticancer activity of mannich bases of type 10 is even scarcer. given the significant antineoplastic properties of compounds 10 [13] , a novel series having substituents r 1 in the phenyl ring that were carefully selected with a view to impart a variety of physicochemical properties has been designed and synthesized [37] . since a gradual release of mannich base 10 from niosomes had improved its bioactivity in vivo, amino alcohols 22 (fig. 5) , which may slowly undergo dehydration to yield the desired mannich base 10, were also examined as cytotoxic agents. finally, in order to explore the hypothesis that cytotoxicity would be retained even when a thiol is liberated, the synthesis of adducts 23 was carried out. compounds 10, 22 and 23 ( fig. 5 ) were evaluated against both human widr colon cancer cells and human crl-2522 foreskin fibroblasts. ic 50 values lesser than 10 mm were obtained when compounds 10 were evaluated towards human widr colon cancer cells, and the corresponding candidates 22 also had ic 50 values in the low micromolar range. on the other hand, conversion of mannich bases 10 into the corresponding adducts 23 led to a 37-fold reduction in potency. in addition, compounds 10 and 22 demonstrated a preferential cytotoxicity to cancer cells compared to normal fibroblasts [37] . further studies showed that compounds 10 and 22 are cytotoxic towards a large number of human tumor cell lines, two important features of many of these compounds being their lethal effects toward promyelocytic leukemic hl-60 cells and their selective toxicity for the aforementioned cancer cell line (selectivity index of 10 or more) [38] . because divergence in the mechanism of action is required for drug candidates that are developed to be tumor-specific and spare normal tissues, it is noteworthy that a representative mannich base 10 caused apoptosis and activated caspase-3, caspase-8, and caspase-9 in hl-60 cells, but not in hsc-2 cells. cytotoxic phenolic mannich bases of chalcone analogues (type 11 in fig. 3 ) are well represented in the recent literature. one of the strategies that are available for the synthesis of this type of mannich bases consists in the aminomethylation of chalcone analogues derived from at least either a phenolic aldehyde or a phenolic ketone. in line with this strategy, a series of five mono-mannich bases 24 (fig. 6 ) were obtained through a mannich reaction of chalcone analogues derived from 4-hydroxyacetophenone, employing piperidine as amine reagent [39] . despite the use of an excess of both paraformaldehyde and piperidine, no double mannich bases analogous to 11 were isolated. the evaluation of compounds 24 against androgene-independent prostate cancer (pc-3) cell line showed that although three of them were more potent than the parent chalcone analogues, the most cytotoxic mannich base 24 was 2.5-fold less potent than the reference drug 5fluorouracil. based on correlations between cytotoxicity and hammet constant on one hand and cytotoxicity and partition coefficient on the other hand, the authors hypothesized that an increase in the general hydrophobicity of the molecule would result in enhanced cytotoxicity. therefore, a novel series of mannich bases 24 was designed to incorporate a dibenzylaminomethyl residue as a replacement for the piperidinomethyl group [40] . again, every attempt to obtain double mannich bases by varying the reaction conditions failed, and only mono-mannich bases could be isolated. when evaluated against androgene-independent prostate cancer (pc-3) cell line, these compounds consistently displayed lower cytotoxicity than that of the parent chalcone analogues. unexpectedly, cytotoxicity in the series of mannich bases with a dibenzylaminomethyl residue was also much lower than that of the corresponding mannich bases in the series containing a piperidinomethyl motif, thus invalidating the hypothesis put forth by the authors in the previous study. furthermore, no adduct between ethanethiol and a representative mannich base 24 could be detected after 48 h, whereas the incubation of ethanethiol with the corresponding parent chalcone analogue under the same conditions resulted in formation of small amounts of adduct. the authors concluded that no active cyclohexadienone species are formed following a potential deamination of mannich base 24, and that the introduction of the dibenzylaminomethyl group further reduces the ability of the chalcone moiety to undergo thiol addition. with a view to explore the effect of variation of dialkylamino moiety on the cytotoxicity of phenolic mannich bases of chalcone analogues, 27 candidates were synthesized through aminomethylation of three chalcone analogues derived from 4hydroxyacetophenone and diverse secondary aliphatic amines [41] . equimolar ratio of reactants afforded mono-mannich bases of type 24, which were evaluated against hepatocellular carcinoma (hepg2), human lung carcinoma (sk-lu-1), and human breast cancer (mcf-7) cell lines. mannich bases with 4-phenylpiperazine residue exhibited reduced cytotoxicity towards all three lines of cancer cells, whereas the candidates with 4-methylpiperazine or 4ethylpiperazine residues were the most active in each series, but less cytotoxic than reference drug ellipticine. with respect to the substitution pattern in the b phenyl ring, mannich bases 25 ( fig. 6 ) derived from 4-chlorobenzaldehyde (r 1 ¼ h, r 2 ¼ cl) or 2methoxybenzaldehyde (r 1 ¼ och 3 , r 2 ¼ h) were consistently more active than those derived from 4-methoxybenzaldehyde (r 1 ¼ h, r 2 ¼ och 3 ). the screening identified five compounds whose ic 50 values against mcf-7 cell line were lower than 2 mg/ml, whereas the most cytotoxic compound 25 (r 1 ¼ h, r 2 ¼ cl, nr 2 ¼ 4ethylpiperazinyl) had ic 50 values lower than 2 mg/ml against all three cancer cell lines used in this study. a larger library of phenolic mannich bases of chalcone analogues featuring the dialkylaminomethyl moiety either in ring a or ring b of the chalcone system was synthesized through the clai-seneschmidt condensation of the appropriately substituted mannich bases of phenolic aldehydes or ketones with heterocyclic ketones or aldehydes, respectively [42] . the use of 4-alkoxy-2hydroxyacetophenones as substrates in the mannich reaction yielded a mixture of 5-aminomethylated derivative with the isomeric 3-aminomethylated derivative, the former being the major reaction product in all cases. the adept tailoring of the ratio between the substrate, formaldehyde and morpholine in the mannich reaction of 4-hydroxyacetophenone resulted in the selective preparation of either single or double mannich base from this substrate. on the other hand, 3-hydroxyacetophenone afforded a mixture of 4-morpholinylmethyl derivative with 2morpholinylmethyl derivative and 2,4-bis(morpholinylmethyl) derivative, even when an equimolar ratio between the reagents was used. isovanillin, which underwent aminomethylation only at position 2 with morpholine and piperidine as amine reagents, was employed as an example of a phenolic aldehyde substrate in the mannich reaction. with the help of these intermediates, several small series of mannich bases of heterocyclic chalcone analogues 26e33 (fig. 6 ) were synthesized and evaluated for cytotoxic activity against four human cancer cell lines, namely pc-3, mcf-7, nasopharyngeal carcinoma (kb), and resistant nasopharyngeal carcinoma (kb-vin). the rich diversity within this library comprised of structurally related entities allowed interesting insight on the cytotoxicityestructure relationship. first, the presence of two phenolic groups in ring a seems to enhance the cytotoxic activity, as proven by a candidate of type 26 (r 1 ¼ h, het ¼ 2-pyridinyl), which was the most potent in the entire library against all four types of cancer cell lines. then, the presence of a methoxy group in series 27 (r 1 ¼ ch 3 ) appears to be generally preferable to ethoxy and isopropoxy, whereas a comparison of the cytotoxicity of similar compounds of type 26 and type 27 usually favors the candidates in the latter series, which have the aminomethyl group para to the phenolic hydroxyl. an analysis of the cytotoxicity within series of candidates of type 28 demonstrated that six-membered heterocycles (particularly a 2-pyridinyl residue) are preferred to five membered heterocycles as ring b moieties, and this observation was validated by the inspection of anticancer activity of compounds in series 29. however, the presence of a second morpholinylmethyl group appears to be detrimental to the cytotoxic activity of candidates 29. shuffling of hydroxy and morpholinylmethyl groups in mannich bases 28 and 29 led to compounds in series 30e32, which are generally less cytotoxic than their counterparts derived from chalcone analogues having a 4-hydroxy substituent in ring a. selective high cytotoxicity against mcf-7 cell line was displayed by the compounds in series 33 featuring the morpholinylmethyl moiety in ring b of the chalcone system. overall, more than 80% of the mannich bases in this library of mannich bases of heterocyclic chalcone analogues 26e33 are cytotoxic (ic 50 < 4 mg/ml), while four members of the library are highly cytotoxic (ic 50 < 1 mg/ml) against all four cell lines, and other four against at least three cell lines, with mcf-7 and pc-3 being usually more sensitive than kb and kb-vin cell lines. later, novel mannich bases of type 24 (ar ¼ 3pyridinyl) were evaluated against several cancer cell lines, and the candidates showed cytotoxicity in the low micromolar range only towards promyelocytic leukemic cells (hl-60) and oral squamosa cell carcinomas (hsc-2, hsc-3 and hsc-4), whereas the ic 50 values against non-malignant gingival fibroblasts, pulp cells and periodontal ligament fibroblasts were higher [43] . the tumor selectivity of these mannich bases may be the result of their proven ability to cleave poly[adp-ribose]polymerase-1 in hsc-2 cells, but not in gingival fibroblasts cells. in addition, the cytotoxic activity of mannich bases of chalcone analogues with an aminomethyl moiety in b ring structurally similar to 33 against a panel of breast cancer (mcf7), melanoma (uacc62) and renal cancer (tk10) cell lines was described in a patent [44] . most compounds were active, and some were potent mostly towards the first two cancer cell lines. a series of mannich bases 34 of bichalcone analogues (fig. 6) , in which the two chalcone units are linked through a bis(aminomethyl) function generated by the use of a bifunctional amine reagent such as piperazine, has also been synthesized and evaluated against 25 cancer cell lines [45] . aminomethylation of acetovanillone with piperazine afforded a bis-mannich base, which subsequently led to compounds 34 through a claiseneschmidt condensation with various aldehydes. surprisingly, compound 34 (ar ¼ 2-pyridinyl) was selectively cytotoxic to human tongue squamous carcinoma (cal-27) and human pharyngeal squamous carcinoma (fadu) cell lines, whereas 3-pyridinyl and phenyl analogues were the most cytotoxic compounds towards all cell lines. substitution of the phenyl ring (ar ¼ c 6 h 5 ) with methoxy groups stripped mannich bases 34 of their cytotoxicity towards most cell lines, whereas the decrease in cytotoxic activity induced by the presence of chlorine as substituent was not so drastic. replacement of phenyl with 2-furanyl or 2-thiophenyl led to compounds that are selectively cytotoxic to one or more cell lines, but further substitution with methyl of these five-membered heterocycle renders them devoid of cytotoxicity against all lines. despite a few notable examples of selectivity, the results obtained for this collection of compounds are not very encouraging, and they suggest that the incorporation of a second chalcone unit does not enhance the cytotoxicity of mannich bases derived from chalcone analogues. cytotoxic activity of mannich bases of bichalcone analogues was further explored using candidates with a modified design. the synthetic strategy comprised the synthesis of mono-phenolic mannich bases starting from 4-hydroxyacetophenone or acetovanillone as substrates and employing 1-(4-(piperazin-1-yl)phenyl) ethanone as amine reagent, then the bichalcone unit was generated through a claiseneschmidt condensation of both acetyl functions with aromatic aldehydes [46] . only mannich bases from bichalcone analogues featuring a pyridinyl moiety (such as candidate 35, fig. 6 ) were active towards prostate cancer (du145), non-small cell lung cancer (a549), ileocecal (hct) and nasopharyngeal carcinoma (kb) cell lines with ic 50 values between 0.7 and 4 mm; all other compounds had ic 50 values greater than 20 mm. compared to compound 35, mannich base 36 having a single chalcone unit was less active (ic 50 between 10 and 13 mm). an exploration of the mechanism of action for these compounds suggested that compound 36 most likely acted via the fas/cd95 apoptosis signaling pathway. ferulic acid and its derivatives provide another example of a type of substrate containing an a,b-unsaturated system activated by an electron-withdrawing group, similar to that in phenolic chalcone analogues, from which phenolic mannich bases can be synthesized. the growing body of evidence suggesting that 3 0 -azido-2 0 -deoxythymidine (azt), a known antiviral, also possesses anticancer activity [47e49] has sparked a study aiming at cytotoxic evaluation of a series of conjugates of azt and ferulic acid derivatives [50] . thus, propargyl ester and n-propargylamide of ferulic acid chemoselectively underwent aminomethylation ortho to the phenolic hydroxyl with various secondary aliphatic amines, and the resulting phenolic mannich bases 37 (x ¼ o, nh) reacted through the terminal alkyne moiety with azt via a cu(i)-catalyzed click chemistry process to afford the corresponding 1,2,3-triazoles. evaluation of cytotoxicity for both mannich bases 37 (fig. 7 ) and the related 1,2,3-triazoles against human breast adenocarcinoma (mda-mb-231), lung adenocarcinoma (sk-lu-1) and colon adenocarcinoma (sw480) cell lines showed that only some of compounds 37 were cytotoxic. despite the presence in their structure of an identical scaffold comprising a phenolic mannich bases moiety and an activated carbonecarbon double bond motif that has been deemed responsible for the cytotoxic effect of mannich bases 37, all of the corresponding 1,2,3-triazoles were inactive. out of eight mannich bases of propargyl ester of ferulic acid reported in this study, three were inactive against all three lines, while the rest had weak to moderate cytotoxicity, and the most active candidate (ic 50 ¼ 20e44 mg/ml) was mannich base 37 (x ¼ o) having a pyrrolidinylmethyl moiety. with the exception of mannich base 37 (x ¼ nh) with a piperidinylmethyl moiety, all others candidates derived from n-propargylamide of ferulic acid were inactive. other aminomethylated phenols with cytotoxic activity have been reported besides phenolic mannich bases of chalcone analogues. unfortunately, the wide structural diversity of phenolic substrates from which these phenolic mannich bases originate and the lack of a systematic and comprehensive search for structureecytotoxic activity relationships within a particular type of phenolic substrate undermine any efforts to discover good lead compounds for further development as drugs. phenolic substrates subjected to the mannich reaction with a view to obtain novel cytotoxic agents include both simple and very complex structures. examples that illustrate structurally simple phenolic substrates are 1-naphthol and 8-hydroquinoline, whose mannich bases with piperidine and 4-arylsulfonylpiperazines exhibited growthinhibitory effects towards a panel of carcinoma cell lines, including hela (cervical epithelioid carcinoma cell), bt483 (mammary gland adenocarcinoma cell), skhep (hepatocellular carcinoma cell), and ce81t (esophageal carcinoma cell) [51] . although the cytotoxic effect of aminomethylated naphthols and 8hydroxyquinoline derivatives has been known for some time [52, 53] , a mechanistic study presented in the aforementioned report showed that these phenolic mannich bases induce apoptosis by activation of caspase-dependent pathways. furthermore, upon addition of copper ions, these compounds dramatically stimulate production of reactive oxygen species and activate various kinases, a group of enzymes that are known to be important in the oxidative stress-mediated cell death. candidate 38 (fig. 7) was the most potent in this small series, with a concentration for 50% cell growth inhibition of 0.71 mm; this value decreased to 0.06 mm in the presence of 50 mm copper. a more detailed study [54] of the structureecytotoxic activity relationship within this class of compounds showed that either replacement of sulfonyl function in 38 with a methylene group, or replacement of piperazine ring with an ethylenediamino moiety (as in compound 39, fig. 7 ) led to a significant increase in cytotoxic activity. the cell lines used in this study exhibited selective sensitivity towards different mannich bases, which appeared to be modulated by the nature of the arylsulfonyl group. as for the 8-hydroxyquinoline part of the molecule, substitution at position 5 of the quinoline motif (especially with a nitro group) had a beneficial effect, whereas its replacement with phenol, 3-hydroxypyridine or 1-naphthol led to a decrease of cytotoxic activity [54] . cytotoxicity of enantiomerically-enriched mannich bases 40 (fig. 7) derived from 2-naphthol, aromatic aldehydes and either 4-piperidinol (r ¼ h) or its acetylated counterpart (r ¼ coch 3 ) against murine leukemic l1210 and human lymphoblast molt 4/c8 and cem cell lines has been examined by another study [55] . all of the compounds were only moderately cytotoxic, with ic 50 values in the middle micromolar range, and were also 10e70-fold less potent than that reference drug melphalan. substitution of the aryl group in 40 with r 1 ¼ 4dialkylaminoethoxy resulted in a series of compounds whose cytotoxicity potential against estrogen-responsive human mcf-7 breast cancer cells was found to be comparable to that of tamoxifen. however, removal of the 4-piperidinol moiety from mannich bases 40 led to benzylnaphthols with enhanced cytotoxicity against mcf-7 cells, which is most likely due to their binding and antagonistic effects against human estrogen receptor alpha [55] . flavones represent another type of phenolic substrate from which cytotoxic mannich bases have been synthesized. because flavones such as chrysin bear structural resemblances to androgens, mannich bases 41 fig. 7) have been designed as inhibitors of human aromatase, an enzyme which converts androgens to estrogens, and therefore represents a key target in the treatment of hormone-dependent tumors, including breast cancer [56] . several single and double mannich bases of chrysin were found to inhibit human aromatase more effectively than reference drug aminoglutethimide [57] . in addition, mannich bases 41 (r ¼ oh, r 1 ¼ h, r 2 ¼ aminomethyl) of apigenin ( fig. 7 ) have been prepared from aliphatic primary and secondary amines via chemoselective aminomethylation at c-8 in the benzopyran ring system [58] . antiproliferative activity of these mannich bases against four human cancer cell lines, namely human cervical (hela), human liver (hepg2), human lung (a549), and human breast (mcf-7) cancer cells, was determined using the standard 3-(4,5-dimethylthiazol-2-diphenyl-tetrazolium) bromide (mtt) assay. pyrrolidine mannich base of apigenin was the most promising compound in this series, its inhibition of cell proliferation being greater than 90% against all four cell lines at a concentration of 1 mg/ml. many natural or synthetic carbazoles, either simple or condensed with other heterocycles (such as pyridocarbazoles, indolocarbazoles, pyranocarbazoles, pyrrolocarbazoles, etc), have been reported as anticancer agents. a recent study examines the cytotoxicity of a series of oxazinocarbazoles, which were the major products arising from the mannich reaction of n-substituted 2-or 4-hydroxycarbazoles with primary amines (fig. 8 ) [59] . under the appropriate reaction condition, 4-hydroxycarbazoles yielded 2,3,4,7-tetrahydro [1, 3] oxazino [5,6c]carbazoles 42, whereas 2hydroxy-9-methylcarbazole led to a mixture of regioisomeric 2,3,4,7-tetrahydro [1, 3] oxazino [6,5-b] carbazoles 43 and 2,3,4,7tetrahydro [1, 3] oxazino[5,6-a]carbazoles 44. use of allylamine, 3,3-dimethylallylamine or benzylamine as amine reagents afforded 44 as the major product, while isomer 43 was the major component of the mixture when 2-pyridinylmethylamine was employed. in addition, small to moderate yields of bis-mannich bases 45 or 46 were isolated from n-substituted 4-hydroxycarbazoles and 2hydroxy-9-methylcarbazole, respectively, but only when 2pyridinylmethylamine was employed as amine reagent. evaluation of the antiproliferative action of these compounds against cem (t cell leukemia), jurkat (acute t cell leukemia), raji (burkitt's lymphoma), mcf-7 (breast cancer cells) and caco-2 (colorectal cancer) using the wst-1 colorimetric assay showed, after the primary screening at 100 mm, that bis-mannich bases 45 and 46 were less active than the oxazinocarbazoles. in the series of compounds 42, the best antiproliferative effect was observed for candidates having either an allyl or a prenyl group at the carbazole nitrogen atom and an allyl group at the oxazine nitrogen atom. thus, jurkat and raji cell lines. the majority of candidates 43 and 44 exhibited significant antiproliferative action at 100 mm, and compound 43 (r ¼ 2-pyridinylmethyl) was the most active towards jurkat and raji cell lines (ic 50 ¼ 12 mm) [59] . aminomethylated derivatives of hydroxycarbazoles have been also mentioned in a different study [60] , which described the synthesis of a small series of phenolic mannich bases 47 (fig. 8 ) obtained from 5-substituted 2-hydroxy-5h-benzo[b]carbazole-6,11-diones along with their in vitro anticancer evaluation at national cancer institute (nci) using an in-house developed screening panel of approximately 60 cell lines derived from nine different types of cancer. only one mannich base 47 (r ¼ 4-h 3 coc 6 h 4 ) was more active than the parent benzocarbazoledione, and a compare analysis [61] revealed that its mechanism of action is novel and does not resemble the known mechanisms of action for standard anticancer drugs, but this candidate was not selected for further studies concerning its interaction with dna. in a related report, phenolic mannich bases 48 of 5-hydroxy-1h-naphtho [2,3-g] indoles were found to be inactive in a similar screening [62] . quinones are a class of compounds that have been widely investigated as anticancer agents [63] . besides anthracycline antibiotics, other natural hydroxyquinones such as plumbagin [64, 65] , juglone [66, 67] or lapachol [68] and their derivatives have been reported to exhibit significant cytotoxicity. the mannich bases of another natural phenolic quinone, namely lawsone, and their pt(ii) complexes 49 ( fig. 9) have been synthesized and shown to be highly cytotoxic towards six cancer cell lines: mda-mb-435 (melanoma), hl-60 (promyelocytic leukemia), hct-8 (colon), sf-295 (brain), ovcar-8 (ovary) and pc-3 (prostate) [69] . the ligands and the complexes that have long alkyl chains (r ¼ n-heptyl or ndecyl) were the most active (the complexes were actually more cytotoxic than cisplatin), whereas the neutral complexes (x ¼ cl) were generally more cytotoxic than the corresponding charged complexes (x ¼ h 2 o or nh 3 ). examination of the mechanism of action for some of these complexes has shown that aqua complexes 49 were more efficient inhibitors of ethidium bromide intercalation into dna than amino complexes, and candidate 49 (r ¼ (ch 2 ) 3 ch 3 , x ¼ h 2 o) was more efficient than cisplatin [70] . the same aqua complex also induced dna strand breaks, while the corresponding amino complex was ineffective. the ability of these complexes to inhibit topoisomerase i was also examined. most chlorido and amino complexes were as active as reference drug camptothecin in the dna relaxation assay, and did not cause major unwinding of dna, with the exception of complex 49 (r ¼ n-decyl, x ¼ cl). in addition, cellular platinum accumulation was shown to increase with the increase of the length of the alkyl chain of the amino moiety in the mannich base ligand. the chlorido pt(ii) complexes were oxidized to the corresponding chlorido pt(iv) complexes, but the cytotoxicity of these new complexes was comparable to the cytotoxicity of the parent pt(ii) complexes, presumably owing to the rapid reduction of pt(iv) complexes before entering the cancer cells [71] . furthermore, miscellaneous aminomethylated phenols from structurally diverse substrates have been reported as anticancer agents (fig. 10) . thus, a small series of seven phenolic mannich bases 50 were synthesized through aminomethylation of naturally occurring antibiotic lasalocid, with simultaneous elimination of the carboxyl group neighboring the phenolic hydroxyl [72] . antiproliferative effect of mannich bases 50 was evaluated against mcf-7 (human breast adenocarcinoma), a549 (human lung adenocarcinoma), ht-29 (human colon carcinoma) and p388 (murine leukemia) using either mtt or sulforhodamine b (srb) assay, and four candidates were more cytotoxic towards a549, ht-29 and mcf-7 cell lines that anticancer drug cisplatin. these candidates also presented higher selectivity towards cancer cells than towards balb/3t3 (normal murine embryonic fibroblast) or hlmec (human lung microvascular endothelial) cell lines. the lack of activity of the other three mannich bases was attributed to the aralkyl or long alkyl chains in the amine moiety of these compounds [72] . camptothecin, another naturally occurring phenolic substrate and lead compound for a plethora of cytotoxic substances, was converted into the oxazino derivatives 51 (fig. 10 ) by means of the mannich reaction using primary aliphatic and aromatic amines [73] . evaluation of these novel hexacyclic camptothecin derivatives towards nine human cancer cell lines (bxpc-3, nci-446, mcf-7, hepg-2, a549, a2780, bel7402, ht-29, and kb), using mtt assay and camptothecin and topotecan as reference compounds, showed that most of them exhibit cytotoxicity towards several cell lines that is superior or comparable to topotecan, while only a few of the candidates presented cytotoxicity comparable to camptothecin. because candidates 51 (r ¼ c 2 h 5 or n-c 3 h 7 ) were the most potent antiproliferative agents in this series, the presence of a small alkyl group at the nitrogen in the oxazine moiety seems to be preferable for a high cytotoxicity [73] . a series of oxazino derivatives 52 (r 1 ¼ ch 3 ) (fig. 10) were also prepared from g-tocotrienol and primary amines via the mannich reaction, whereas d-tocotrienol afforded under the same conditions a mixture of oxazino derivatives 52 (r 1 ¼ h) and 53, in which the former is the major component [74] . no reaction occurred when secondary amines were used instead, but two phenolic mannich bases 54 were obtained indirectly from the corresponding oxazino derivatives 52. out of 42 candidates in this library, thirty compounds had greater antiproliferative activity against the highly metastatic þ sa mouse mammary epithelial cancer cells than that of the parent tocotrienols (ic 50 ¼ 3 mm), and seven candidates had ic 50 values in the nanomolar range. mannich bases 54 were less active than the corresponding oxazino derivatives 52 against nci's standard panel of 60 cell lines, which suggests that the oxazine ring is an essential pharmacophore for the cytotoxic activity of these tocotrienol derivatives. generally, the oxazino derivatives 52 of dtocotrienol were more active than the corresponding isomers 53 derived from g-tocotrienol, and a long alkyl chain at the nitrogen atom (preferably with a terminal hydroxyl group) proved beneficial for the antiproliferative activity. the same conclusions were drawn after the evaluation of structureeantimigratory activity relationship using the highly metastatic mdamb-231 breast cancer cell line [74] . novel g-quadruplex ligand/alkylating hybrid structures 55 ( fig. 10) were obtained by tethering a naphthalene diimide core having g-quadruplex recognizing properties to phenolic mannich bases using flexible spacer [75] . the assessment of cytotoxic effects of these compounds 55 (n ¼ 1, 2, or 3) and their corresponding methiodides against human embryonic kidney 293t cell line by mtt assay suggests that the length of the spacer between the core and the phenolic mannich bases moiety modulates the cytotoxicity: candidates 55 having two-carbon atoms and one-carbon atom spacers were the most active (ic 50 4.5 and 10.5 mm, respectively), whereas the mannich base 55 with a three-carbon atoms spacer was less active. cytotoxicity of these compounds parallels their ability to alkylate dna, and the grafting of the alkylating mannich base moiety to the central core contributes to the enhancement of the g-quadruplex folding induction and stabilization. a similar g-quadruplex ligand/alkylating hybrid structure was shown to significantly slow the growth of melanoma cells by causing telomere dysfunction and down-regulation of telomerase expression [76] , which suggests that these hybrids could be possible candidates for the development of novel targeted anticancer therapies. in connection to this, the methiodide of double mannich base 56 (fig. 10 ) with a quinazoline core was also shown to cross-link linear dna at concentrations as low as 1 mm, and to inhibit dna transcription almost completely at 10 mm [77] . phenolic mannich bases 57 of norvisnagin ( fig. 10 ) were prepared through direct aminomethylation, and their ability to interact with dna was evaluated using both a qualitative binding assay and a colorimetric microassay based on the displacement of methyl green from dna [78] . three of the candidates 57 (r ¼ pyridinyl-2-amino, diethylamino, and methylamino) showed moderate dna binding affinity, and could be potentially cytotoxic. also, mannich bases 58 (r 1 ¼ h) of 1,3-dihydroxyxanthone ( fig. 10 ) displayed moderate to good cytotoxicity against lung cancer (nci-h460), tongue squamosa cell carcinoma (tca-8113), liver cancer (bel-7402), hepatocarcinoma (hepg2), gastric carcinoma (sgc-7901) and urinary bladder carcinoma (t24) in an mtt assay [79] . several reports of mannich bases of indoles as cytotoxic agents are also available in recent literature. cytotoxicity of a few indole mannich bases 59 derived from 4-substituted piperazines (fig. 11 ) was evaluated against liver (huh7), breast (mcf7) and colon (hct116) cancer cell lines using srb assay, and some of these compounds had ic 50 values in the lower micromolar range. compound 59 (r ¼ 3,4-dichlorobenzyl) was cytotoxic towards all three cancer cell lines, and fared better than reference drug 5-fluorouracil (5-fu) [80] . on the other hand, n-mannich bases 60 of 3methylindole did not inhibit the growth of cancer cells or had high ic 50 values. in spite of this fact, a subsequent study [81] was dedicated exclusively to the investigation of cytotoxicity of a novel series of n-mannich bases of type 60 against the same cancer cell lines. the broadening of the nature of substituent at position 4 of piperazine proved favorable, as several compounds reported in this later study presented cytotoxic activity comparable to reference drug 5-fu. a comparison between the morphological features of cancer cells for which apoptosis was induced either by a selected 3metylindole n-mannich base 60 or by paclitaxel suggests that compounds 60 (r 1 ¼ ch 3 ) and paclitaxel share the same mechanism of action. design of novel cytotoxic mannich bases in which indole itself was the substrate for aminomethylation was also revisited using an extended panel of 4-substituted piperazines as amine reagents in aminomethylation [82] . the novel candidates 59 proved to be cytotoxic towards the same cancer cell lines (huh7, mcf7, and hct116); however, no cytotoxicity was observed for the candidates with an electron-withdrawing group (such as 4nitrophenyl, benzoyl or acetyl) as substituent at position 4 of piperazine. other c-mannich bases of indole derivatives have been claimed as potent inhibitors of isoprenylcysteine carboxyl methyltransferase (imct), an enzyme that plays an important role in the posttranslational modification of proteins that are involved in the regulation of cell growth, and therefore represents a potential therapeutic target in oncogenesis. among the few small molecules inhibitors of imct that were discovered so far, the most promising appears to be cysmethynil, an indol-3-ylacetamide derivative which impairs growth factor signaling and induces cell cycle arrest and autophagy. because cysmethynil suffers from poor water solubility and strong binding to plasma proteins, rational modification of this hit compound has been expected to yield more potent imct inhibitors with improved bioavailability. replacement of the acetamide function in cysmethynil with various aminomethyl moieties led to compounds 61 (r ¼ dialkylamino) with an inhibitory effect on icmt that was generally 2e3-fold more potent than that of the parent inhibitor [83] . evaluation of the effects of these candidates on viability of mda-mb-231 human breast cancer cells using the colorimetric tetrazolium assay confirmed the results for icmt inhibition. thus, compounds 61 ( fig. 11 ) were found to be more cytotoxic (ic 50 3e13 mm) than cysmethynil (ic 50 22 mm). other modifications of the lead compound 61 (r ¼ diethylamino) either preserved the potency of the candidates (e.g., shuffling of the methyl group on the phenyl ring), or resulted in a potency decrease (e.g., replacement of n-octyl with prenyl). however, the replacement of m-tolyl moiety in 61 with more polar heteroaromatic rings led to submicromolar ic 50 values in the icmt inhibition assay, and to ic 50 values in the antiproliferative assay on breast mda-mb-231 and prostate pc3 cell lines that are 2e3-fold lower than that of fig. 11 . cytotoxic indole and azaindole mannich bases. the lead 61 (r ¼ diethylamino) [84] . compound 62 (fig. 11 ) was the most potent compound in this series, and presented a series of improvements of the drug-like profile over cysmethynil, such as good solubility in water, acceptable permeability through an artificial membrane, and limited tendency to form light scattering aggregates. using naphtho[2,3-f]indole-5,10-dione as scaffold, a series of 3aminomethylated derivatives was synthesized, and four candidates were evaluated as antiproliferative agents against the standard panel of 60 human cancer cell lines at nci [85] . compounds 63 (r ¼ primary or secondary aliphatic amine residue, r 1 ¼ oh) (fig. 11 ) were less potent than doxorubicin against any of the cell lines, but multidrug resistant breast cancer cells were found to be more sensitive to 63 than to doxorubicin. in addition, mannich bases 63 showed potency for cancer cell lines that are otherwise resistant to anticancer drugs, such as the p-glycoprotein-positive subline of k562 leukemia cells or the p53-null subline of hct116 colon carcinoma cell line. replacement of phenolic hydroxyl groups r 1 in 63 (r ¼ dimethylamino) by 2-aminoethyleneamino moieties led to mixed results, as the potency improved for some of the cell lines and declined for others, but the sensitivity of multidrug resistant breast cancer cells to these modified candidates was completely lost [86] . furthermore, candidate 63 (r ¼ quinuclidin-3ylamino, r 1 ¼ oh) was shown to inhibit topoisomerase i-mediated relaxation of dna, but the suppression of the topoisomerase i activity is presumably the leading although probably not the only factor contributing to cytotoxicity of mannich bases of naphtho [2,3-f]indole-5,10-diones [87] . preobrazhenskaya et al. have also shown that a series of single and double mannich bases 64 (r 1 ¼ h or dialkylaminomethyl) of 3,4-bis(indol-1-yl)maleimides (fig. 11) , structurally related to rebeccamycin or staurosporine, were highly cytotoxic towards к562 and hcт116 cell lines, but their cytotoxicity does not correlate well with their ability to either inhibit protein kinase c-a or constrain activation of multiple drug resistance [88] . mannich bases of an indole isostere, namely 5h-pyrrolo[3,2-d] pyrimidine, have been designed as inhibitors of phosphatidylinositol-3-kinase a (pi3ka), a lipid kinase that modulates activity of the pi3k downstream effectors akt and mtor. since the consequences of biological activation of akt include tumor progression, proliferation, survival, growth, invasion, angiogenesis, and metastasis, pi3ka represents an attractive target for development of anticancer drugs. although aminomethylated pyrrolopyrimidine 65 (fig. 11 ) was an efficient inhibitors of pi3ka (ic 50 ¼ 20 nm) and showed good selectivity for pi3ka over mtor (170-fold) , this compound exhibited low cytotoxicity towards pc3 cancer cells [89] . in addition, all the other analogues of mannich base 65 were found to be even weaker inhibitors of pi3ka than the lead compound. isatin is nowadays a well recognized and privileged scaffold in the design of cytotoxic and anticancer compounds [90] . several isatin-containing substrates, namely isatin and its 5-halogenated analogues, the corresponding imine derivatives obtained from sulfadiazine, sulfadoxine and trimethoprim, and a hydrazone derived from isoniazid, were aminomethylated using gatifloxacin as amine reagent [91] . the resulting mannich bases were tested against nci's standard panel of 60 cell lines using srb assay, and compound 66 (fig. 12 ) emerged as an efficient anticancer agent that was generally more potent than reference drug etoposide against most cell lines in the panel. another library of mannich bases derived from isatin, 4-halogenated isatins and their schiff bases with 2-amino-6-methylbenzothiazole was evaluated for cytotoxic effects on three breast cancer cell lines (mda-mb468, mdamb231 and mcf7) using srb assay [92] . the introduction of a halogen as substituent at position 4 of isatin mannich bases led to an increase in cytotoxicity, and modification of isatins into schiff bases followed by aminomethylation resulted in mannich bases further enhanced the cytotoxicity of these candidates. compounds 67 and 68 ( fig. 12) were the most potent in each series (ic 50 < 20 mm), and more potent than reference drug cisplatin, while their cytotoxicity against normal cells was low. as far as their mechanism of action is concerned, compound 67 induced cell cycle arrest in g2/m phase at concentrations similar to those observed for cell growth inhibition, whereas compound 68 did not [92] . furthermore, another collection of mannich bases of isatin imines generated either from 2aminobenzimidazole or 2-amino-4,5-dihydrothiazole was evaluated against mcf-7 human breast adenocarcinoma cell line using srb assay, but the cytotoxicity of these compounds was moderate (ic 50 > 20 mm) and inferior to that of doxorubicin [93] . generally, aminomethylated schiff bases of isatin derived from 2aminobenzimidazole were more cytotoxic than their counterparts derived from 2-amino-4,5-dihydrothiazole, compound 69 ( fig. 11) being the most potent in this collection (ic 50 ¼ 22.6 mm). cytotoxic mannich bases of isatins were also designed employing hybridization of isatin with a 4-aminoquinoline scaffold to generate the substrate subjected to aminomethylation [94] . the cytotoxicity of these compounds towards breast cancer cell lines mda-mb468 and mcf7 was moderate (ic 50 values between 15 and 65 mm), but the activity improved slightly in the series of the corresponding thiosemicarbazones (ic 50 in the range of 10e55 mm). mannich bases 70 and 71 (fig. 12) were the most potent candidates in every series (2e3-fold more cytotoxic than cisplatin), and they preferentially inhibited the growth of cancer cell over normal cells. studies using flow cytometry also suggest that these compounds induce cancer cell death by apoptosis. beside isatin derivatives, several other classes of nh-azoles have been aminomethylated with a view to synthesize cytotoxic mannich bases. 2,3-dihydro-1,3,4-oxadiazole-2-thiones appear to be the preferred substrate within this category, most likely owing to their straightforward preparation. starting from methyl salicylate, good yields of the corresponding oxadiazolethione mannich bases 72 ( fig. 13) were obtained in three steps [95] . most compounds in this collection arise from primary aromatic amines diversely substituted in the aromatic ring, whereas mannich bases 72 derived from secondary aliphatic amines are poorly represented. selected candidates from this series have been initially evaluated by nci against a panel consisting of nci-h460 (lung), mcf7 (breast), and sf-268 (glioblastoma) cancer cell lines using srb assay. seven of these thirteen mannich bases 72, most of them having either chlorine or carboxy group as substituent in the aromatic ring of the amine moiety, reduced the growth of nci-h460 cell line to 30% or less, and they were further selected for the standard 60-cell lines panel assay. compounds 72 (r ¼ h, r 1 ¼ 3-clc 6 h 4 or 4-clc 6 h 4 ) presented higher cytotoxicity than reference drugs 5-fu or cyclophosphamide against most cancer cell lines in this panel [95] . the ability of several oxadiazolethione mannich bases 73 featuring variously substituted aromatic ring at position 5 of the oxadiazolethione ring (r 1 ¼ h and r ¼ no 2 , oh, ch 3 , or r ¼ r 1 ¼ cl) to inhibit the growth of tumors in vivo has been also investigated [96] . tumor volume and tumor weight in mice injected with ehrlich ascites carcinoma cells were reduced by 52e74% at a dose of 50 mg candidates 73 (fig. 13 ) per kg body weight, whereas similar dose of reference drug 5-fu inhibited tumor formation by 93%. mannich bases 73, especially those having hydroxyl, methyl or chloro substituents on the phenyl ring at position 5, were the most potent. also, the counts of red blood cells and leukocytes, as well as hemoglobin levels, have been restored almost to the normal values in mice treated with mannich bases 73 [96] . aminomethylated oxadiazolethiones 74 (fig. 13 ) were generally more cytotoxic against colon carcinoma (ht29) and less cytotoxic against breast cancer (mcf7) cells using srb assay, but the most potent candidate 74 (nr 2 ¼ nhc 6 h 4 ch 3 -4) was 5-fold less cytotoxic than reference drug doxycycline [97] . cytotoxicity of a series of mannich bases 75 (fig. 13 ) of a norharmaneoxadiazolethione structural hybrids was evaluated against a panel comprising melanoma (uacc-62), breast (mcf7), ovarian resistant (nci/adr), renal (786-0), lung (nci-460), prostate (pco-3), ovarian (ovcar) and colon (ht-29) cell lines using srb assay [98] . several of candidates 75 (r ¼ h or n(ch 3 ) 2 , r 1 ¼ isopropylamino or benzylamino) exhibited a broad spectrum cytotoxic activity, and aminomethylation of the parent oxadiazolethiones significantly enhanced the cytotoxicity of each resulting mannich bases 75 compared to that of the corresponding substrate. furthermore, mannich bases 76 of a fluoroquinoloneeoxadiazolethione hybrid were prepared using either secondary aliphatic amines or substituted arylamines as amine reagents [99] . the in vitro evaluation of cytotoxicity against hep3b cancer cells using mtt assay showed that compounds 76 ( fig. 13 ) were more potent than the parent fluoroquinolone pefloxacin. also, mannich bases in this series derived from aliphatic amines were generally more cytotoxic than those derived from arylamines, and candidate 76 (r ¼ n(ch 3 ) 2 ) was even more potent than reference drug bisantrene. 2,3-dihydro-1,2,4-triazole-3-thiones could also act as substrates for the preparation of cytotoxic n-mannich bases. schiff bases obtained from 5-aryloxymethyl-4-amino-3-mercapto-1,2,4-triazoles and 3(5)-substituted pyrazole-4-carboxaldehydes were aminomethylated using either morpholine or diphenylamine to afford mannich bases 77 (fig. 13) , whose cytotoxicity against hepg2 cell line was evaluated using mtt assay [100] . out of five tested candidates, mannich bases 77 having a morpholine moiety were more potent than those with a diphenylamine moiety, but they were still 2e3-fold less cytotoxic than reference drug doxorubicin. eleven dimethylamine mannich bases 78, that were obtained through aminomethylation of schiff bases derived from a 4-amino-1,2,4triazole-3-thione having at position 5 a moiety originating from fluoroquinolone ofloxacin, were screened for cytotoxicity against murine leukemia cell line (l1210) and human leukocytoma cell line (hl60) [101] . mannich bases 78 (fig. 13) were generally more cytotoxic than the corresponding parent schiff bases, and candidates 78 with a hydroxyl group in the aromatic ring of the azomethine function (r ¼ oh) were the most cytotoxic compounds in the series (ic 50 values in the range of 0.14e0.83 mm). mannich bases of thiazolidinone derivatives have also been investigated as cytotoxic agents. c-aminomethylation of two 4thiazolidinones using secondary aliphatic amines afforded mannich bases 79 (x ¼ o, ch 2 ) (fig. 14) , which were evaluated against colon (hct116) and breast (t47d) cancer cell lines by srb assay, but their cytotoxicity was generally moderate to low (ic 50 values between 13 and 50 mm) [102] . in addition, n-aminomethylation of two thiazolidine-2,4-diones (r ¼ cl, och 3 ) with morpholine, piperidine and variously 1-substituted piperazines yielded mannich bases 80 (fig. 14) , which were investigated at nci against the standard 60-cell lines panel using srb assay, and proved to be virtually inactive (growth inhibition for the most sensitive cell line between 18 and 33%) [103] . several examples of p-mannich bases derived from organic esters of phosphorous acid that were disclosed as cytotoxic agents are available in the literature. thus, a-aminophosphonates 81 were synthesized from alkyl phosphites (r 3 ¼ ch 3 , c 2 h 5 , n-c 3 h 7 , i-c 3 h 7 , n-c 4 h 9 ), fluorine-substituted benzaldehydes and 2aminobenzothiazoles, and their cytotoxicity was evaluated against pc3 (prostate), a375 (melanoma), a431 (epidermoid carcinoma), and bcap-37 (breast) cancer cells using mtt assay [104] . most mannich bases 81 ( fig. 15 ) exhibited low to moderate growth inhibition of a375 and bcap-37 cells, but their cytotoxicity towards pc3 and a431 cells was generally greater. the nature of the fluorine substituent appears to influence cytotoxicity, as candidates 81 having fluorine directly attached to the aromatic ring are more potent than those with a trifluoromethyl substituent. an improvement of cytotoxicity with the increase of the length of the alkyl residue r 3 from the initial phosphite was also noted. p-mannich bases 82 (r 1 ¼ ch 3 , c 2 h 5 , i-c 3 h 7 ) (fig. 15 ) were prepared using thieno [3,2-c] pyridine-2-carboxaldehyde as aldehyde component in the mannich reaction of dialkyl phosphites with variously substituted arylamines [105] . the majority of candidates 82 showed good cytotoxicity against esophageal cancer cells (ec109), but they were generally more potent against hepatocellular liver carcinoma cells (hepg2) at a concentration of 50 mg/ml. a few aaminophosphonates 83 (fig. 15 ) were obtained through a mannichtype process from diphenyl phosphite, 3-acetylpyridine and variously substituted anilines, and proved to be cytotoxic to hepg liver carcinoma cell line (ic 50~1 5 mm) and mcf7 breast adenocarcinoma cell line (ic 50~2 0 mm) using mtt assay [106] . although these candidates were approximately 7-fold less cytotoxic than reference drug doxorubicin, their ld 50 values were greater than the corresponding ic 50 values, making them safe to use. aminomethylation of diethyl phosphite with either aromatic aldehydes and aromatic diamines or terephthaldehyde and various amines led to bis(aaminophosphonates) 84 or 85 (fig. 15 ), respectively, whose cytotoxicity against jurkat (t-cell lymphoma), raji (burkit's lymphoma) and mcf-7 (breast cancer) cell lines was determined using mtt assay [107] . in this structurally diverse series of compounds, a few were devoid of cytotoxicity while most of them were moderately cytotoxic. compound 85, derived from tryptamine as amine reagent in the mannich reaction, emerged as the most potent in this series, its cytotoxicity being comparable to that of doxorubicin. furan belongs to the category of electron-rich heterocycles known to undergo electrophilic substitutions such as the mannich reaction with great ease. for example, aminomethylation of synthetic lactone of natural furanditerpene 6a,7b-dihydroxyvouacapan-17b-oic acid as substrate and using various secondary aliphatic amines led to the furan mannich bases 86 (fig. 16 ) [108] . antiproliferative effect of these compounds was more potent than that of the parent lactone against a panel of nine cancer cell lines (melanoma (uacc-62), breast (mcf7), ovarian expressing the resistance phenotype for adryamycin (nci-adr/res), kidney (786-0), lung, non-small cells (nci-h460), prostate (pc3), ovarian (ovcar-03), colon (ht-29), and k562 erythromyeloblastoid leukemia), as determined by srb assay. mannich bases 86 were also equipotent to reference drug doxorubicin against at least one, if not many, of these cancer cell lines, often with ic 50 values as low as 1 mg/ml. in addition, 1,2,4-triazolo[1,5-a]pyrimidine-7-amines having at position 2 a side chain capped with a furan ring were aminomethylated with various secondary aliphatic amines to yield a large series of furan mannich bases 87 (fig. 16 ) [109, 110] . cytotoxicity of compounds 87 against liver cancer (bel-7402) and fibro sarcoma (ht-1080) cells was established using mtt assay, and the results suggest that both the substitution of the arylamine moiety and the nature of the aliphatic amino residue in the aminomethyl function have a significant influence on the potency of these candidates. in particular, the presence of a 4-trifluoromethyl group or a 4-fluoro-3-trifluoromethyl substitution pattern in the arylamine moiety led to high cytotoxicity against both cell lines at levels comparable to that of reference drug cisplatin. also, the presence of dimethylamino, 1-piperidinyl or 1-pyrrolidinyl moieties as aliphatic amino residues in the aminomethyl group of mannich bases 87 appears to result in significant antiproliferative effects, while 4-morpholinyl or 4-methylpiperazinyl moieties drastically decrease or even abolish cytotoxicity. titanium-based chemical entities enjoy the reputation of having a tremendous potential against solid tumors. recently, a number of studies presented the synthesis and the cytotoxicity for a series of titanocenes, some of them featuring various aminomethylated fivemembered heterocycles as substituent of either one or both cyclopentadiene moieties [111e114]. thus, titanocenes 88 and 89 ( fig. 17) containing mono-and bis-aminomethylated pyrroles, respectively, or titanocenes 90 and 91 (fig. 17 ) having a dimethylaminomethyl group at position 1 and 3 of indole, respectively, as well as titanocene 92 (fig. 17 ) presenting an aminomethylated imidazole ring, have been screened against pig kidney epithelial cells (llc-pk1) or human renal cancer cells (caki-1) and found to have ic 50 values quite similar to that of cisplatin (in the range of 5e10 mm). the presence of at least one aminomethyl function in their structure is claimed to be crucial for the high cytotoxicity of these titanocenes. the aminomethyl groups are able to coordinate the titanium center, and could therefore stabilize the mono-or dication formed through hydrolysis of either one or both chlorine atoms inside the cell. this results in enhanced interactions between titanocene and dna, leading to cell death at low concentrations. aminomethylation of terminal alkynes has also been employed for the generation of mannich bases with potential cytotoxic effect. 10-(prop-2-ynil)phenothiazines underwent aminomethylation with secondary aliphatic amines to give propargylamines 93 (r 1 ¼ h, cl, cf 3 ) (fig. 18 ), which were first evaluated for cytotoxic activity using two hematological tumor cell lines, namely hl60 (promyelocytic leukemia) and the ccrf/cem (lymphocytic leukemia), and were afterwards tested, in combination with doxorubicin, for ability to revert activity in the corresponding multidrug resistant variants, hl60r and cem/vbl300 [115] . although most compounds 93 were devoid of significant antiproliferative effect on the sensitive cell lines, a few of them were highly cytotoxic for the resistant cell lines, and appear to arrest cells in g1 phase of the cell cycle, unlike classic anticancer agents. furthermore, several mannich bases 93 were able to restore sensitivity to doxorubicin of the resistant cell lines, an effect that was concentration-dependent and reached maximum at 10 mm. propargylamines 93 seem to induce apoptosis by activating the caspase cascade, although neither the extrinsic nor the intrinsic pathways appear to be involved in apoptosis [115] . betulin derivatives bearing an ethynyl function have also served as starting materials for acetylenic mannich bases with cytotoxic potential. for example, propargylamines 94 ( fig. 18 ) have been obtained from alkynes prepared through addition of an organometallic derivative of acetylene to the carbonyl function in betulonic acid esters [116] , and alkynes synthesized from betulin through a sequence comprising the oxidation of the primary alcohol function to aldehyde, followed by addition of an organometallic derivative of acetylene to aldehyde carbonyl, afforded propargylamines 95 (fig. 18 ) [117] . cytotoxicity of these mannich bases was evaluated on a panel of nine human cancer cell lines using srb assay, and the results prove that some of these compounds show considerable toxicity (ic 50 values as low as 4 mm). introduction of the aminomethyl group significantly improved the cytotoxicity of propargylamines 94 and 95 compared to that of the parent alkynes, presumably by enhancing their solubility and bioavailability. highly hydrophobic and sterically hindered amino moieties, such as dicyclohexylamino or dibenzylamino, led to a decrease in cytotoxicity of the corresponding aminomethylated alkynes. mannich bases of this type were shown to act by triggering apoptosis, although a complementary process of autophagy could also be involved. in an attempt to circumvent the resistance mechanism developed by cancer cells after prolonged administration of doxorubicin and address the issues of poor solubility, short lifetime and high toxicity of prodrug doxoform [118] , a second-generation, watersoluble prodrug of doxorubicin was developed by conjugation of the active drug with salicylamide by means of a mannich reaction [119] . doxorubicinesalicylamide conjugate doxaliform 96 (fig. 19 ) has a half-life of approximately one hour, and was more cytotoxic than doxorubicin against mcf-7 sensitive (4-fold) and mcf-7/adr resistant (10-fold) breast cancer cells. furthermore, doxaliform is amenable to functionalization with a view to provide a site for attachment of a releasable targeting group that might direct the conjugate to a specific receptor that is overexpressed by cancer cells. because many breast cancer cells overexpress estrogen receptor a, this receptor was chosen for targeting by doxasaliform having tethered a hydroxytamoxifen moiety, as in prototype 97 ( fig. 19 ) [120] . cytotoxicity of these candidates as a function of the length of the tether showed that a triethylene glycol unit provides a lead compound whose growth inhibition of four selected breast cancer lines (mcf-7, mcf-7/adr, mda-mb-231 and mda-mb-435) was enhanced up to 140-fold relative to doxorubicin. later work confirmed that uptake of hydroxytamoxifen-targeted doxorubicinesalicylamide conjugate is mediated by both the antiestrogen binding site and estrogen receptor [121] . also, several doxorubicineformaldehyde conjugates tethered to the nonsteroidal antiandrogen cyanonilutamide were designed, synthesized and evaluated as androgen receptor-targeted ligands for specific delivery of the conjugate to prostate cancer cells [122] . such a construct was later used in studies intended to evidence binding to androgen receptor in live pc3 prostate cancer cells and the subsequent translocation of the construct bound to the receptor to the nucleus, but the results were not very promising [123] . other efforts [124] were directed towards the conjugates of doxasaliform with the cyclic peptide neme-vrgdf (known as cilengitide), which is a potent antagonist of a v b 3 integrin involved in many cell-matrix recognition and cell adhesion phenomena, and plays an important role in angiogenesis and tumor metastasis. although the complete construct maintained a high affinity for a v b 3 integrin, the ic 50 for growth inhibition of mda-mb-435 cells was 2-fold greater than that of doxasaliform; the poor results have been tentatively blamed on limitation of drug delivery caused by the specific reduced abundance of receptors in this type of cell. eventually, because doxasaliform is not as active as prodrugs doxoform or doxazolidine, this line of research was terminated. however, the topic was later revisited by other authors, who reported the synthesis of constructs derived from either doxorubicinesalicylamide, daunorubicinesalicylamide or their 2-acyloxymethyl derivative, and amino-terminated poly(ethylene glycol), and their use for in vitro and in vivo studies [125] . these constructs presented cytotoxicities comparable to those of the parent drugs, and the lifetime of one of these constructs was determined to be longer than that of doxorubicin. also, the construct was more efficient than doxorubicin at reducing the weight of s-180 xenografted tumors [125] . cytotoxic mannich bases derived from miscellaneous, structurally unrelated substrates are grouped in the last paragraph of this section. 2-aminomethylated 9-alkyl-1,2,3,4-tetrahydrocarbazole1-ones 98 (fig. 20) show moderate to potent cytotoxicity towards a549 (human lung adenocarcinoma), sgc (human gastric cancer), k562 (human myelogenous leukemia), hct116 (human colorectal carcinoma), and kb-vcr (human oral cancer) cells using mtt assay [126] . one of candidates 98 (r ¼ c 2 h 5 , r 1 ¼ ch 3 ) was more cytotoxic than reference drug taxol against a549 cell line (ic 50 ¼ 70 nm), and at least one of its mechanism of action appears to be the inhibition of tubulin polymerization. a series of 3aminomethyl imidazo[2,1-b]benzothiazoles 99 (fig. 20) were evaluated for antiproliferative activity against hepatocellular carcinoma (hepg2), human breast (mcf-7) and human cervical (hela) cancer cell lines using mtt assay [127] . mannich bases 99 inhibited the proliferation of cancer cells at concentrations lower than 10 mm, arrested the cell cycle at g2/m phase while downregulating cyclin b and upregulating chk2 protein, and appeared to induce apoptosis based on the elevated levels of caspase-3. 6-cinnamoyl-benzoxazol-2-ones (r 1 ¼ h, ch 3 o) were the substrates used for the synthesis of mannich bases 100 (fig. 20) , which had high to moderate cytotoxicity (ic 50 between 5 and 40 mm) towards human pre-b-cell leukemia cell line bv-173 and chronic myeloid leukemia k-562, and appear to exert their cytotoxic action at least in part through induction of apoptosis [128] . replacement of the methoxy substituent in compounds 100 with chlorine led to a marginal improvement of ic 50 values [129] . a series of mannich bases 101 (r ¼ h, ch 3 ; x ¼ ch 2 , o, n-r 1 ) (fig. 20 ) of fused pyridazinone derivatives were synthesized and tested in vitro using srb assay to determine their growth inhibitory properties at a single 10 mm dose against sixty different human tumor cell lines. most of them showed no activity of all, but two candidates moderately inhibited the growth of non-small cell lung cancer (ekvx and hop-92) and glioblastoma (snb-75) cell lines [130] . an impressive number of articles dealing with the antibacterial activity of mannich bases have been published in the last decade. from a structural point of view, mannich bases reported in these studies are derived from nearly all of the major types of substrates capable of undergoing aminomethylation. these mannich bases have been evaluated against both gram-positive and gramnegative bacteria belonging to various families. the evaluation of the antibacterial activity was performed using different screening methods, and not always the standardized versions, and this complicates the interpretation and the comparison of results obtained in different studies. owing to the particular relevance of tuberculosis, the reports concerning the screening of mannich bases against mycobacterium species are presented in a separate section. ketonic mannich bases with antibacterial potential are at the heart of several studies within the period of time covered by this review. aminomethylation of a,b-unsaturated cyclic ketones with variable ring sizes afforded a library of compounds 102 (n ¼ 1e4) (fig. 21 ) derived from secondary cyclic aliphatic amines and having on the aromatic ring either no substituent at all, or a methyl group, or a variable number of methoxy groups [131] . evaluation of the antibacterial activity of these mannich bases against a panel of both gram-positive and gram-negative bacteria using the serial dilution method showed that the candidates derived from seven-or eightmembered a,b-unsaturated cyclic ketones were the least active of all, and that the nature of the amine moiety, or the number and the position of the methoxy groups on the aromatic ring, did not influence the antibacterial activity. none of the compounds were active against pseudomonas aeruginosa, and only a few were moderately active against escherichia coli. mannich bases 102 affected gram-positive bacteria (minimum inhibitory concentration (mic) < 12.5 mg/ml in most cases), but the candidates were less potent than reference antibiotics. another set of mannich bases 103 ( fig. 21 ) obtained from benzo-fused cyclic ketones (indanone, 1tetralone, benzosuberone) were tested under the same conditions against an extended panel of gram-positive and gram-negative bacteria [132] . in this collection, both the nature of the amine moiety and the alkoxy substituent r 1 influence the antibacterial activity, to a greater extent for gram-positive bacteria and to a lesser extent for gram-negative bacteria. indanone derivatives were active against both classes of bacteria (mic between 1.56 and 25 mg/ml), whereas tetralone and benzosuberone derivatives were mostly active against gram-positive bacteria (presumably due to the higher outer membrane permeability of these bacteria). also, a statistical comparison between the antibacterial activity of mannich bases 102 and mannich bases 103 showed that the latter were more active than the former [131, 132] . based on oxazolidinone antibacterials linezolid and eperezolid, a small series of mannich bases 104 (r ¼ nhcoch 3 or nhcsch 3 ) (fig. 21) derived from cyclohexanone or benzo-fused cyclic ketones was synthesized and evaluated against three selected gram-positive microorganisms using the standard serial dilution method [133] . all of the compounds having an acetamido group had low antibacterial activity, but the replacement of this group with thioacetamido restored the activity up to the level exhibited by the parent oxazolidinone antibacterial. further modification (r ¼ nhcsnh 2 ) produced a candidate whose antibacterial activity was superior to that of linezolid. 4,6-dimethoxybenzofuran-3(2h)-one double mannich bases 105 (fig. 21 ) had moderate to high antibacterial activity, as determined using disc diffusion method at a concentration of 0.5% in dmso [134] . the majority of compounds 105 were active against e. coli, and those derived from pyrrolidine, diethylamine and di-nbutylamine as amine reagents showed significant antibacterial activity (zone of inhibition 17e22 mm) towards most bacteria, comparable to that of reference drug gentamycin (zone of inhibition 18e24 mm). on the other hand, compound 105 derived from n-ethylmethylamine was inactive (no inhibition at concentrations higher than 100 mg/ml). also, structurally diverse types of mannich bases derived from acetophenones or 2-acetylthiophene, such as mono-mannich bases of type 8 (r ¼ ch 3 ) (fig. 3) , bis-mannich bases of type 13 (r ¼ ch 3 ) (fig. 4) , and piperidinols of type 14 (r ¼ ch 3 ) (fig. 4) , as well as their azine derivatives 16 (fig. 4) , are devoid of antibacterial activity against a wide range of human-and plant-pathogenic bacteria [135] . methiodide 106 (fig. 21 ) of dimethylamine mannich base of acetophenone was the sole active compound in this series, and only against staphylococcus aureus, but the diameter of the inhibition zone measured 9 mm (compared to 25 cm in the case of reference drug ofloxacin), and its mic was 500 mg/ml. the antibacterial activity of ketonic mannich bases generated from arylamines and aromatic aldehydes was also investigated by several groups. starting from cyclohexanone, a set of eleven compounds 107 was obtained, and screening against four common bacteria using serial dilution method showed that many of these candidates have excellent antibacterial activity, comparable to that of ceftriaxone [136] . however, the lack of rational design and systematic use of the aldehyde and amine components used to generate mannich bases 107 ( fig. 21 ) preclude any logical conclusions regarding sar in this collection. use of four differently substituted acetophenones, 4-fluorobenzaldehyde and several para-substituted anilines led to mannich bases 108 (fig. 21) , which were screened against four common bacteria [137] . most of these compounds were inactive, but candidate 108 (r 1 ¼ 2-br, r 2 ¼ f) was more potent than reference drug ampicillin against all four microorganisms, whereas another candidate 108 (r 1 ¼ 2-br, r 2 ¼ h) was more potent than ampicillin against e. coli and s. aureus. arylamine mannich bases 109 and 110 ( fig. 21 ) were obtained from 3-acetylcoumarine and 2-acetylbenzofuran, respectively, and evaluated against e. coli, s. aureus and p. aeruginosa using disc diffusion method [138] . since most compounds in this series are derivatives of 4-aminobenzoic acid, it has been expected that at least a few of these compounds have good antibacterial activity. three candidates 109 (r ¼ h, cl or f) had antibacterial activity comparable to that of reference drug streptomycin, but the rest were almost inactive. the series of candidates 110 provided only one remarkably active mannich base (r ¼ n(ch 3 ) 2 ), but the rest of the compounds with a benzofuran moiety are generally more active than coumarine-derived candidates 109. 3-(arylamino)-1-ferrocenyl-1-propanones 111 ( fig. 21) showed broad spectrum activity against both gram-positive and gram-negative bacteria, the highest degree of growth inhibition being obtained for s. aureus [139] . mic values varied between 0.2 and 12.5 mg/ml, making these compounds approximately 100-fold less active than reference drug tetracycline. because compounds 112 ( fig. 21) with a similar structure but with a phenyl ring instead of ferrocene have been reported to possess moderate to high antibacterial activity [140] , it appears that the replacement of phenyl in 112 with ferrocene could be responsible for the substantial decrease in activity recorded in the case of compounds 111. aminomethylated phenols have also been reported to have antibacterial activity. mannich bases 113 ( fig. 22 ) obtained from 4t-butylcatechol and secondary aliphatic amines have been screened for antibacterial activity against seven types of bacteria, but their potency was rather low to moderate [141] ; their corresponding copper(ii) complexes fared better, as two of them had mics comparable to that of chloramphenicol (12.5 mg/ml). the mannich reaction of a derivative of another dihydroxylic phenol with either secondary aliphatic amines or primary arylamines afforded compounds 114 (fig. 22 ), whose zones of inhibition for three common bacteria, determined at two concentrations (100 and 200 mg/ml) using disc diffusion method, were smaller than those observed for reference drug ofloxacin at 20 mg/ml [142] . because chemical modification of natural antibiotic novobiocin by means of aminomethylation was hypothesized to increase permeability through the outer membrane of gram-negative bacteria, phenolic mannich bases 115 (fig. 22) were designed, synthesized and evaluated against s. aureus (one of novobiocin's usual targets), francisella tularensis and e. coli [143] . candidates 115 were significantly less potent than novobiocin against these three microorganisms, the antibacterial activity of the most potent of these compounds being almost 100 times weaker than that of novobiocin. thirteen novel phenolic mannich bases 116 (fig. 22 ) derived from lawsone, benzaldehydes and primary aliphatic amines, together with their corresponding copper(ii) complexes, were tested for antibacterial activity against seven types of bacteria [144] . with a few exceptions, mannich bases 116 were generally more potent than the corresponding complexes, presumably due to the greater solubility of the pro-ligands. two mannich bases 116 had antibacterial activity comparable or higher to that of chloramphenicol against bacillus subtilis, e. coli and s. aureus, whereas the other compounds inhibited bacterial growth at concentrations greater than 200 mmol/l. antibacterial activity of fused oxazines obtained through the mannich reaction of phenols and naphthols with primary amines has also been examined. 6-acetyl-1,3-benzoxazines 117 ( fig. 22) were screened at 50 mg/ml against three common microorganisms using disc diffusion method, and they showed good growth inhibitory activity towards s. aureus, but only moderate potency against e. coli and b. subtilis [145] . the antibacterial activity was evaluated for 1,3-benzoxazines 118 ( fig. 22 ) substituted with chloro and methyl groups in the aromatic ring, bis(1,3-benzoxazines) 119 ( fig. 22) , naphtho[1,2-e]-1,3-oxazines 120 (fig. 22) , as well as naphtho[2,1-e]-1,3-oxazines 121 (fig. 22 ) using serial dilution method [146] . regardless of the aliphatic or aromatic nature of the moiety at the nitrogen atom, most compounds, and especially naphthoxazines 120 and 121, had mic values greater than 50 mg/ ml, but two benzoxazines 118 derived from 4-chlorophenol and aromatic amines were more potent than ampicillin against e. coli, whereas compound 119 derived from 2,4-dichlorophenol was equipotent to gentamycin against s. aureus. in addition, benzoxazines 118 and naphthoxazines 120 and 121 having benzazole moieties at the nitrogen atom were tested against four common types of bacteria [147] . although the majority of the compounds were inactive, the antibacterial activity of few candidates was 2-folde15-fold greater than that of reference drug tetracycline; the enhancement of activity for these candidates has been associated with the presence of a benzimidazole system at the nitrogen atom and at least one halogen in the phenolic starting material. in contradiction to the previously mentioned results, a number of naphtho[2,1-e]-1,3-oxazines 121 obtained from variously substituted arylamines were found to be quite active as antibacterial agents towards e. coli and b. subtilis [148] . these compounds were generally more active against the latter pathogen, and the candidates derived from 4-fluoroaniline, 4-ethoxyaniline and 2,4,6tribromoaniline were even more potent than reference drug streptomycin. the mannich reaction of phenols fused with heterocycles has also been investigated for the preparation of antibacterials. mannich bases of 8-hydroxyquinoline have been quaternized at the heterocyclic nitrogen atom with bromoacetic acid esters of superior alcohols (r ¼ n-c 12 h 25 , n-c 16 h 33 , n-c 18 h 37 ) to give compounds 122 (x ¼ o, ch 2 ) (fig. 22 ) [149] . the antibacterial activity of candidates 122, determined for three concentrations (1, 2.5 and 5 mg/ml) using disc diffusion method, showed that the compounds were active towards both gram-positive and gram-negative bacteria, but the presence in their structure of long alkyl chains rather than the aminomethyl function is most likely responsible for their activity. phenolic mannich bases 123 (r 1 ¼ h, br) ( fig. 22) were evaluated against e. coli and bacillus cirroflagellosus at 1 mg/ml using disc diffusion method, but their antibacterial activity was generally weak, with the exception of candidates derived from morpholine as amine reagent [150] . aminomethylated derivatives 41 (r ¼ oh, fig. 7 ) also manifested antibacterial activity in various degrees; the most active candidates were the mannich base derived from cyclohexylamine, which was as potent as tetracycline against b. subtilis (mic 3.9 mg/ml), and the mannich base derived from morpholine, which had the same antibacterial activity as ampicillin against s. aureus (mic 2 mg/ml) [58] . phenolic mannich bases derived from 3-hydroxy-4h-pyran-4ones received special attention as potential antibacterials. allomaltol (5-hydroxy-2-methyl-4h-pyran-4-one) was converted into mannich bases 124 (fig. 23) , whose antibacterial activity against four different gram-positive bacteria was only moderate (mic > 32 mg/ml) [151] . on the other hand, the antibacterial activity of mannich bases 125 ( fig. 21 ) derived from chlorokojic acid was superior to that of analogous 124, and the candidates were shown to possess a broad spectrum, while being more active against standard strains (mics between 1 and 32 mg/ml) than towards clinical, drug-resistant isolates [152] . there is no striking difference between the antibacterial activity of aminomethylated derivatives 125 having 4-benzylpiperazines and those having 4-substituted piperidines as amine moiety. the growth inhibition of grampositive bacteria (with the exception of enterococcus faecalis) occurred at mic values that were lower than those required for the growth inhibition of gram-negative bacteria. mannich base 125 with 1-(4-chlorobenzhydryl)piperazine as amine moiety seems to be best compound in this series, but its activity was consistently lower than that of any reference antibacterial drug. subsequently, a novel series of mannich bases 125 was synthesized, this time using various 4-(substituted aryl)piperazines as amine reagent, but the compounds in this collection were weaker antibacterials than analogous 125 derived from 4-benzylpiperazines [153] . screening of another novel set of compounds 125 with either 4benzylpiperazines of 4-arylpiperazines did not identify any compounds with improved or remarkable antibacterial activity, as the best candidates in this study had mic values between 4 and 16 mg/ ml [154] . however, when piperazinyl-substituted fluoroquinolones were employed as amine reagents in the mannich reaction of 3hydroxy-4h-pyran-4-ones as substrates, the resulting hybrids 126 (r ¼ cl) (fig. 23 ) had a broad spectrum and were highly active against a panel comprising both gram-negative and gram-positive bacteria [155] . generally, aminomethylated derivatives of chlorokojic acid (126, r ¼ cl) were more potent antibacterials than aminomethylated derivatives of kojic acid (126, r ¼ oh). mannich base 126 (r ¼ cl) derived from fluoroquinolone ciprofloxacin was the most potent candidate in the series. replacement of the quinolone scaffold in candidates 126 derived from norfloxacin with a naphthyridone moiety (as in mannich bases 126 derived from enoxacin) resulted in decreased antibacterial activity. among the bacteria used in this study, e. coli and klebsiella pneumoniae were the most sensitive microorganisms to hybrids 126. docking of the most active compound into topoisomerase ii dna-gyrase active site (which is the traditional target of quinolones) showed that mannich base 126 derived from ciprofloxacin binds in a manner similar to ciprofloxacin to the enzyme's active site, and that the 3hydroxypyran-4-one moiety is anchored with additional hydrogen bonding within the binding pocket, thus increasing the stability of the inhibitoreenzyme complex. mannich bases of isatin derivatives have also been investigated as antibacterial agents. aminomethylation of isatin semicarbazone with (hetero)arylamines afforded mannich bases 127 (fig. 24 ), whose antibacterial activity was moderate towards e. coli and good towards s. aureus [156] . in addition, a series of mannich bases 128 (r ¼ secondary aliphatic amines) (fig. 24 ) derived from a hydrazone of isatin incorporating the biologically relevant moieties of 1,3,5triazine, sulfa drugs and azacarbazole had moderate to good antibacterial activity against the previously mentioned microorganisms [157] . hydrazidones obtained from isatin and hydrazides of variously substituted acetic acids have also been aminomethylated with a view to synthesize antibacterial mannich bases. for example, mannich bases 129 24 ) derived from substituted isatins and morpholine, piperidine or 1-methylpiperazine generally showed poor antibacterial activity against the two aforementioned types of bacteria, with the exception of compound 129 (r ¼ 4-methylpiperazinyl, r 2 ¼ 5-br), whose inhibition determined by disc diffusion method was approximately half of that for reference drug gentamycin [158] . another collection of mannich bases 129 (r 1 ¼ 4-or 4,5-substituted 2-ethylphenyloxy) generated from substituted isatins as substrates and morpholine or piperidine as amine reagents exhibited weak to moderate antibacterial activity towards e. coli, s. aureus and shigella flemeri (zone of inhibition 12e20 mm) compared to norfloxacin (zone of inhibition 26e28 mm) [159] . schiff bases generated from isatin and various (hetero)aromatic amines represent another type of isatin-derived substrate that was subjected to aminomethylation to obtain potential antibacterial agents. the use of isatin schiff bases in the mannich reaction with 2-((2,6-dichlorophenyl)amino]) phenylacetic acid as the amine reagent yielded compounds 130 (r 1 ¼ substituted phenyl) (fig. 24) , which proved to be 3e12-fold less potent than reference drug ciprofloxacin against an array of bacteria [160] . when 3-chloro-4-fluoroaniline was used to generate schiff bases from isatin and 5-chloroisatin, aminomethylation with secondary aliphatic amines gave mannich bases 131 (fig. 24) ; these compounds had moderate to good activity against e. coli, s. aureus, p. aeruginosa and salmonella typhi in disc diffusion assay, and showed also moderate to good b-lactamase inhibitory activity [161] . schiff base of 5chloroisatin and trimethoprim was aminomethylated to give compounds 131 (r 1 ¼ 4-amino-5-(3,4,5-trimethoxybenzyl)pyrimidin-2-yl), but only mannich bases 131 derived from ciprofloxacin, lomefloxacin or gatifloxacin as amine reagents in the mannich reaction were at least as potent, if not more potent, than the corresponding parent fluoroquinolones against a large panel of bacteria [162] . antibacterial activity of mannich bases 131 (r 1 ¼ 5benzyl-3-thioxo-2h-1,2,4-triazol-4-yl) derived from schiff bases of isatin or 5-halogen-substituted isatins and an aminotriazolethione was generally good against four common microorganisms, as the size of the inhibition zones for some of the candidates (especially those derived from halogenated isatins and having piperidine or morpholine residues in the aminomethyl group) was comparable to the size of the inhibition zone for reference drug ciprofloxacin [163] . recently, mannich bases 132 ( fig. 24 ) obtained using schiff bases derived from 5-fluoroisatin and 4-arylideneaminoanilines as substrates and ciprofloxacin as amine reagent were shown to be generally less potent antibacterials than reference drug ciprofloxacin, although some candidates had mic values comparable to those of ciprofloxacin against the investigated bacteria [164] . a large number of papers published in the last decade report the antibacterial activity of mannich bases of 2,3-dihydro-1,2,4triazole-3-thiones. from a structural point of view, mannich bases from triazolethiones that were synthesized through aminomethylation in these reports fall into two major categories: 5substituted 2-aminomethyl-2h-1,2,4-triazole-3-thiones 133 and 5-substituted 2-aminomethyl-4-arylideneamino-2h-1,2,4triazole-3-thiones 134. the relevant information from these studies (i.e., substituents at position 4 and 5 of the triazole ring, amine reagents used in aminomethylation, microorganisms employed in the antibacterial evaluation) is presented in a condensed manner in table 1 . in the series of compounds 133a, the nature of the amine moiety in the aminomethyl group appears to be critical for the antibacterial activity, as mannich bases from piperazines were consistently more potent than mannich bases from arylamines, and some of them were even more potent than reference drug ampicillin [165] . a comparison between antibacterial activities of 133a and structurally related 134b suggests that the replacement of substituent at position 4 of the triazole ring in 133a with hydroxybenzylideneamino in 134b further enhances the antibacterial activity. although it was shown that substitution with chlorine of the phenyl at position 5 of the triazole ring improves the antibacterial activity in the series of compounds 133b and 133c, and that aminomethylation also increases the bacterial growth of mannich bases 133c compared to the parent triazolethione, no candidates with substantial antibacterial activity could be singled out from these two collections [166e168]. however, use of ciprofloxacin as amine reagent in the synthesis of mannich bases 133c and 133d led to a substantial increased antibacterial activity of these compounds, and some of them were as potent as reference drugs ciprofloxacin and vancomycin against several types of bacteria and methicillin-resistant s. aureus (mrsa), respectively [169] . mannich bases 133e or 134f having a diphenylsulfone moiety at position 5 of the triazole ring had only weak antibacterial activity [170] . a small number of mannich bases 133f, especially those having a halogen as substituent of the phenyl at n-4 of the triazole ring, inhibited the growth of gram-positive bacteria [171] . mannich bases 133g, especially candidates with morpholine, 4benzylpiperazine, n-methylpiperidine and trifluoromethylphenylpiperazine in the aminomethyl group, had very good antibacterial activity (mic 1.56e12 mg/ml) [172] , whereas analogous 133h having 2-furyl instead of 2-thiophenyl were less potent (inhibition zones of 6e13 mm, compared to 10e35 mm for ampicillin) [173] . the three mannich 133i bases reported in a study gave interesting results, as the candidates derived from 1methylpiperazine (inhibition zones of 23e30 mm for all bacteria) and 2-(4-morpholinyl)ethylamine (inhibition zones of 14e22 mm for some of the microorganisms under evaluation) were more potent than reference drug ampicillin, whereas the bis-mannich base 133i derived from piperazine was inactive [174] . however, further elaboration of 133i into compound 133p abolished the antibacterial activity [174] . mannich bases 133j, which feature a 3pyridinyl moiety at position 5 of the triazole ring, were generally poorer antibacterials than reference drug ampicillin, although there were isolated examples amongst these candidates that show more potency than ampicillin against certain bacteria [175] . furthermore, the replacement of 4-pyridinyl with 2-quinolinyl as substituent at position 5 of the triazole ring, and modification of phenyl into benzyl as substituent at position 4 of the triazole ring led to inactive mannich bases 133k [176] . both types of mannich bases 133l and 134l, featuring a 1,2,4-triazole moiety at position 5 of the triazolethione scaffold, showed good antibacterial activity, but compounds 134l were generally more potent than 133l, and two of candidates 134l actually had mic values comparable to those of reference drug ciprofloxacin [177] . mannich bases 133m and 133n (continued on next page) [165] were devoid of effective antibacterial activity [178, 179] , as was structurally related candidate 133o (a singular and notable exception is this compound's activity against bacillus cereus) [179] . mannich bases 133q were also inactive as antibacterials, except for a few candidates that were more potent against p. aeruginosa than reference drug ampicillin [180] . every member of the series of [197] h primary arylamines diphenylamine piperazines s. aureus s. pyogenes [198] mannich bases 134a was active against the tested bacteria, but not as potent as reference drug nitrofurazone [181] . in addition, the nature of substituent at position 5 of the triazole ring in the series of compounds 134a had no noticeable influence on their antibacterial activity, but the data (based on a single example) suggest that presence of chlorine in the aromatic ring of substituent x of the pyrazole moiety could improve the activity. mannich bases 134c were mostly active against s. aureus and b. subtilis, and candidates derived from ethyl piperidine-4-carboxylate were generally more potent than those derived from piperazines [182] . it should be noted that the presence of halogen in the structure of 134c (r 2 ¼ 2,6-difluorophenyl or 2,6-dichlorophenyl) did not enhance the antibacterial activity of these mannich bases. in contrast, substitution with halogen in compounds 134d (e.g., r 2 ¼ 2,4dichlorophenyl) led to the most potent candidates in the series, and their antibacterial activity was comparable to that of reference [203] drug ciprofloxacin [183] . use of 2,4-dichloro-5-fluorophenyl moiety at position 5 of the triazole ring in mannich bases 134e also produced candidates with good to excellent antibacterial activity [184] . compounds 134e having secondary aliphatic amines in the aminomethyl group were generally more potent than those having arylamines, even if the anilines used in aminomethylation were substituted with additional halogen atoms [184] . although mannich base 134g had no antibacterial activity, a close analogue of 134g such as compound 135 (fig. 25 ) was 1.5e3-fold more potent than ampicillin against most bacteria in the panel, with the exception of s. aureus [185] . replacement of 4-methylpiperazin-1yl with 4-morpholinyl in the aminomethyl group of mannich base 134g, and use of substituted phenyl other than 4-fluorophenyl as r 2 afforded structurally related candidates 134h with moderate antibacterial activity [186] . antibacterial activity of mannich bases 134i was moderate to good, but even the most potent compounds in this series (all of them having a 4-methylpiperazin-1-yl moiety in the aminomethyl group) were at least 4-fold less active than reference drug ciprofloxacin [187] . mannich bases 134j also had moderate to good antibacterial activity (inhibition zones of 12e22 mm), but were less potent than tetracycline (inhibition zones of 25 mm) [188] . overall antibacterial activity was reasonable in the series of mannich bases 134k, while a few compounds had mic values against various bacteria close to those determined for reference drugs [189] . a few mannich bases 134m were more potent against p. aeruginosa than reference drugs levofloxacin and amikacin, while most candidates exhibited broad, moderate to good antibacterial activity [190] . evaluation of mannich bases of 2,3-dihydro-1,2,4-triazole-3ones as antibacterial agents received little attention in recent literature. a small series of six mannich bases 136 (fig. 25 ) derived from 4-(substituted (hetero)arylidendeamino)-5-methyl-1,2,4triazole-2-ones was synthesized and tested against seven types of bacteria, and the antibacterial activity of the candidates ranged from moderate to excellent [191] . all compounds were more potent than reference drug ampicillin against e. coli and p. aeruginosa, and candidate 136 (r 1 ¼ 2-hydroxyphenyl, nr 2 ¼ 2-(4-morpholinyl) ethylamino) was at least as active as ampicillin against all types of bacteria used in the study, with the exception of s. aureus. out of mannich bases of type 137 (fig. 25) , only those derived from morpholine or piperidine were excellent, broad spectrum antibacterials, whereas other analogues were either inactive, or weak antibacterials, or moderately active against the tested bacteria [192] . a single mannich base 138 (fig. 25 ) of 1,2,4-triazole-3-ones having a 2-quinolinyl moiety as substituent at position 5 of the triazole ring was synthesized and evaluated for antibacterial activity, and its effect on e. coli and p. aeruginosa was comparable to that of ampicillin [176] . three mannich bases having a 3-pyridinyl moiety at position 5 of 1,2,4-triazole-3-one scaffold, analogous to compounds 133j derived from 1,2,4-triazole-3-thione, had moderate to good activity against most bacteria in the panel, but were not superior to reference drug ampicillin [175] . antibacterial activity of mannich bases 139 of 2,3-dihydro-1,3,4oxadiazole-2-thiones has been investigated extensively. the structural features of the compounds reported in these studies have been summarized in table 2 , along with the microorganisms used for screening. mannich bases 139a had moderate to good antibacterial activity (mic values between 6.25 and 25 mg/ml), but none was as potent as reference drug ciprofloxacin, and no definite sar could be inferred from the biological results [193] . the growth inhibition of mannich bases 139b appears to be modulated by the nature of the amine in the aminomethyl residue; thus, candidates derived from 3-trifluoromethylaniline were the most potent in this series and had antibacterial activity comparable by that of reference drug ciprofloxacin, followed in order by mannich bases 139b derived from morpholine, 2-chloro-5-methylaniline and 4-chloro-2-trifluoroacetylanline [194] . in the case of mannich bases 139c, candidates derived from secondary aromatic amines were inactive, whereas the remaining compounds were less active against gram negative bacteria, and more active against gram positive bacteria (mic values 2e8-fold lesser than those of reference drug ampicillin) [195] . both mannich bases 139d reported in this study [185] had moderate to good antibacterial activity, and both were more potent than ampicillin against e. coli and e. faecalis, but the candidate derived from 1-methylpiperazine was generally more potent than mannich base derived from 2-(4-morpholinyl)ethylamine. in the case of thiazole-containing mannich bases, antibacterial activity of compounds 139e was moderate (mic values between 16 and 62.5 mg/ml) [187] , whereas compounds two of compounds 139f emerged as effective antibacterials, especially against gramnegative bacteria, with mic values 2e4-fold lesser than those for reference drug chloramphenicol [196] . several mannich bases 139g (nr 2 ¼ nhc 6 h 4 f-4, nhc 6 h 4 cl-4, nhc 6 h 4 cf 3 -2, nhc 6 h 3 f 2 -2,5) had antibacterial activity comparable to that of reference drug penicillin, and, for some bacteria, even comparable to reference drug streptomycin [197] . mannich base 139h (nr 2 ¼ 1-piperazinyl) was equipotent to reference drug ciprofloxacin against s. aureus, but the antibacterial activity of the rest of candidates in this series was weaker than that of ciprofloxacin against the tested bacteria [198] . the compounds reported in a study, including mannich bases 139i, are claimed to exhibit moderate antibacterial activity, but lack of access to the original information (which is only provided in the online edition as supplemental material, and is missing) makes data assessment impossible [199] . phenylpiperazine-containing mannich base 139j was generally more potent that candidate 139j derived from ethyl isonipecotate, but both had moderate antibacterial activity compared to reference drug ampicillin [176] . three out of eight synthesized mannich bases 139k were screened for antibacterial activity, but their growth inhibition was only weak to moderate (inhibition zones of 12e26 mm) compared to that of reference drug chloramphenicol (inhibition zones of 37e44 mm) [200] . none of the 21 synthesized mannich bases 139l presented any antibacterial activity at the maximum concentration tested (250 mg/ml) [98] . mannich base 139m was the only compound with antibacterial activity in the structural diverse library evaluated in the study, but its effects were moderate at best [189] . screening results for mannich bases 139n were also disappointing, as they only barely inhibited the growth of e. coli at a concentration of 10 mg/ml [174] . out of two synthesized mannich bases 139o, the candidate having a morpholine residue in the aminomethyl group displayed excellent antimicrobial activity against all the tested microorganisms, while the candidate having a methylpiperazine residue had good or moderate activities against most bacteria in the panel, with the exception of e. coli and k. pneumoniae [190] . the growth inhibition exerted by mannich bases 139p was moderate compared to reference drugs, and it was uninfluenced by the nature of the amine moiety in the aminomethyl group [177] . nalidixic acid-based oxadiazolethione mannich bases 139q exhibited very weak antibacterial activity (mic values > 750 mg/ml) compared to reference drug streptomycin (mic ¼ 5 mg/ml), and only towards b. subtilis, but some of the structurally related mannich bases 140 of 2,3-dihydro-1,3,4-thiadiazole-2-thione ( fig. 25 ) were quite active (mic values as high as 6.25 mg/ml) against the microorganisms used in the study [203] . finally, mannich bases 141 having a 3,4dichlorophenyl moiety at position 5 of 2,3-dihydro-1,3,4oxadiazole-2-one ring (fig. 25) were inactive against s. aureus, e. coli, p. aeruginosa and bacillus megaterium [204] . two studies presented the synthesis and antibacterial evaluation of c-mannich bases 142 of thiazolidinones (fig. 26) having a thiazolyl-2-imino substituent at position 2 [205, 206] . while candidates 142 having alkyl or aryl groups as r 1 substituent at c-5 of thiazolidinone ring showed no antibacterial activity against a panel of eight bacteria, some of their analogues unsubstituted at c-5 (r 1 ¼ h) had weak antibacterial activity against s. aureus (mic values of 20e40 mg/ml). two of mannich bases 143 (r 1 ¼ 2-hoc 6 h 4 ) of thiazolidinones featuring a 6,8-dibromo-4oxoquinazolin-3-yl moiety (fig. 26 ) were 2-fold less potent against s. typhimurium (when nr 2 ¼ diethylamino) and 4-fold less potent against b. cereus (when nr 2 ¼ 1-piperidinyl) than reference drug ciprofloxacin [207] . antibacterial activity of mannich bases 144 (fig. 26 ) was found to be more potent (mic values between 6.25 and 100 mg/ml) than that of parent thiazolidinones, and the sar suggests that the nature of substituent r 1 influences significantly the ability of these compounds to inhibit the growth of various bacteria [208] . aminomethylation of pyrimidine-2-thiones and pyrimidine-2ones, substrates that can be easily obtained in a considerable structural variety through a simple biginelli reaction, has also been investigated in relation with the antibacterial activity of the resulting mannich bases. thus, pyrimidine-2-thione mannich base 145 (fig. 26 ) was obtained using natural alkaloid cytosine as amine reagent in aminomethylation, and its evaluation as antibacterial agent showed that it is a potent growth inhibitor of s. aureus and b. subtilis, and it has weak activity against p. aeruginosa and e. coli [209] . double mannich bases 146 (fig. 26 ) of pyrimidine-2-thiones (x ¼ s) were good antibacterial agents (zones of inhibition of 96 to 88% of the zone of inhibition for reference drug streptomycin) against e. coli and b. subtilis [210] , and analogous double mannich bases 146 of pyrimidine-2-ones (x ¼ o) were even more potent, with the exception of the candidate having a 4-methoxyphenyl moiety at position 4 of the pyrimidine ring (r ¼ 4-och 3 , r 1 ¼ h) [211] . taking advantage of the lability of the proton located at the nitrogen atom in the amide function, several n-mannich bases 147 of 5-chloro-2-methoxybenzamide ( fig. 27 ) obtained from either sulfonamides or common secondary amines as amine reagents have been synthesized and evaluated for antibacterial activity against a panel of bacteria [212] . candidates 147 derived from sulfonamides were more potent than the parent compounds, whereas mannich base 147 derived from morpholine was an antibacterial agent with broad spectrum and good activity. n-mannich bases 148 of glutarimides (r 1 ¼ h, c-c 5 h 9 , c-c 6 h 11 , 4-clc 6 h 4 ) (fig. 27 ) have been screened for antibacterial activity, and claimed to be potent very potent, although no comparison to currently-in-use antibacterials was available [213, 214] . compounds 148 derived from sulfonamides showed improved growth inhibition activity of the tested microorganisms over the corresponding parent amines, whereas analogues generated from secondary aliphatic amines were generally equipotent to those obtained from sulfonamides [213] . also, n-mannich bases 149 of succinimide (r 1 ¼ h or c 6 h 5 , nr 2 ¼ nhc 6 h 5 , 2-pyridinyl) (fig. 27 ) and an n-mannich base from phthalimide were weak to moderate antibacterials against e. coli, s. typhi and b. subtilis [215] . well-known antibiotics have also been subjected to aminomethylation with a hope of increasing their antibacterial activity or improving their bioavailability. hybrids 150 of tetracycline and sulfonamides ( fig. 28 ) have been generated using the mannich reaction, and their screening against salmonella enteritidis and pasturella multocida showed that their antibacterial activity is higher than that of the parent sulfonamides; unfortunately, no comparison with the activity of tetracycline or a reference drug is provided in the study [216] . aminomethylation is one of the modifications that have also been explored in the case of vancomycin. after an n-decylaminoethyl moiety was introduced into the structure of vancomycin with a view to restore antibacterial activity against vancomycin-resistant enterococci while retaining potency against mrsa, grafting a hydrophilic group has been considered as a way to reduce the overall lipophilicity of the n-decylaminoethylmodified vancomycin and to restore the initial favorable distribution properties of vancomycin. several types of amine reagents (amino acids, amino sugars, phosphonic acids) have been considered for the synthesis of mannich bases 151 (fig. 28) , and some of these modifications led to candidates active against vancomycinresistant bacteria, and ultimately to the discovery of telavancin (td-6424) as a lead compound with improved absorption, distribution, metabolism and excretion (adme) properties over ndecylaminoethylvancomycin [217] . (fig. 28 ) was subsequently screened against a large number of predominantly gram-positive isolates with developed antibacterial resistance, and showed to be highly active against methicillin-resistant staphylococci (mic 90 0.5e1 mg/ml), streptococci (mic values 0.12 mg/ml), and vanb-type enterococci (mic values 2 mg/ml) [218] . with respect to its mechanism of action, telavancin inhibited late-stage peptidoglycan biosynthesis in a substrate-dependent fashion, bound to cell wall with high affinity, and perturbed bacterial cell membrane potential and permeability [219] . aminomethylation of vancomycin has also been used as the first step in the construction of glycopeptide/b-lactam heterodimers via linkage of aminomethylated vancomycin and various cephalosporin cores through an adipic acid moiety [220] . these heterodimers were all found to exhibit excellent potency against a range of important gram-positive bacteria, and a subset of these candidates also demonstrated rapid bactericidal activity against mrsa, whereas two of the most attractive compounds have been shown to exhibit in vivo efficacy 40 fold greater than that of vancomycin. finally, a patent claims a series of mannich bases of vancomycin as compounds suitable for oral delivery and having enhanced antibacterial potency [221] . antibacterial activity of mannich bases derived from miscellaneous substrates is covered in the last paragraph of this section. mannich bases 152 (r ¼ ch 3 , oc 2 h 5 ) (fig. 29 ) derived from either ethyl acetoacetate or diethyl malonate as substrates, variously substituted benzaldehydes as aldehyde components and benzyl carbamate as amine reagent had poor to moderate activity against five types of common bacteria [222] . hydrazidones derived from isoniazid and 2-alkoxybenzaldehydes have been aminomethylated at position ortho to the alkoxy group to give mannich bases 153 (fig. 29) . a few members of this collection having an ethoxy group demonstrated at concentration of 100 mg/ml antibacterial activity superior to that of reference drug amoxicillin at 50 mg/ml [223] , whereas candidates having a propoxy group were less potent [224] . mannich bases 154 derived from 7-methyl-2-(substituted aryl) imidazo[1,2-a]pyridines (fig. 29 ) and having two halogens as substituents in the phenyl ring at position 2 of the fused heterocyclic system were the most potent in this series against e. coli, p. aeruginosa, s. aureus and streptococcus pyogenes [225] . mannich bases 155 derived from an imidazo[2,1-b]-1,3,4-thiadiazole ring system (fig. 29) showed weak activity against gram-positive bacteria and moderate activity against vibrio cholera, but their growth inhibition activity of e. coli was comparable to reference drug norfloxacin [226] . evaluation of the antibacterial activity of mannich bases derived from 2-alkyl-3-hydroxy-pyridine-4(1h)-ones showed that only one candidate 156 (fig. 29 ) had moderate activity against s. enteritidis (16 mg/ml) and s. aureus (16 mg/ml) compared to reference drug ciprofloxacin (1 mg/ml and 0.5 mg/ml, respectively, for the mentioned microorganisms) [227] . mono-mannich bases 157 (r 1 ¼ ch 3 ) and double mannich bases 158 generated from sydnones ( fig. 29) were both found to inhibit moderately the growth of four standard microorganisms, regardless of the nature of the amine reagent used in aminomethylation, but no useful conclusions regarding sar in this series could be drawn for further development [228] . also, most mannich bases 157 (r 1 ¼ och 3 ) had weak to moderate activity against both gram-positive and gramnegative bacteria, with the exception of candidate 157 (r 1 ¼ och 3 , nr 2 ¼ 4-nitrobenzothiazole-2-ylamino), which was as potent as reference drugs ciprofloxacin and ampicillin against gram-positive bacteria [229] . in contrast, aminomethylation of another sydnone derivative using various primary and secondary aliphatic amines was reported to occur in the at n-1 in the pyrazoline ring to give mannich bases 159 instead (fig. 29) , which had good antibacterial activity compared to reference drug ampicillin against four common bacteria, and particularly against b. subtilis [230] . the copper(ii) complex of pyrazole c-mannich base 160 (fig. 29 ) inhibited the growth of b. subtilis at concentrations as low as 1.25 mm, most likely by promoting mutagenesis and inducing cell death [231] . screening of a few of pyrazolone n-mannich bases 161 (fig. 29 ) against various bacteria resulted in inhibition zones that were comparable to those of reference drug ciprofloxacin, but the mic values for these candidates were ultimately far greater from those of ciprofloxacin [232] . some of the acetylenic mannich bases 162 (r 1 ¼ c 6 h 5 , 4-clc 6 h 4 ; r 2 ¼ c 6 h 5 , 1-c 10 h 7 ) (fig. 29 ) had antibacterial activity comparable to reference drug ofloxacin against s. aureus, fewer showed good activity against e. coli, and only one candidate was equipotent to ofloxacin against p. aeruginosa [233] . various substrates (e.g., benzimidazole, 3methylpyrazole-5(4h)-one, succinimide, phthalimide or naphthalimide) were aminomethylated using norfloxacin as amine reagent, and some of the corresponding mannich bases were more potent than the parent fluoroquinolone, especially against e. coli and p. aeruginosa [234] . sulfonamides and primary or secondary aliphatic amines were employed as amine reagents in aminomethylation of isoniazid to give mannich bases 163 (fig. 29) , and some of the candidates had antibacterial activity that was superior to that of the parent sulfonamides, whereas mannich base 163 (nr 2 ¼ nhch 3 ) was the most potent compound in the series against s. aureus and b. anthracis [235] . use of hydantoins as substrates in the mannich reaction led to 3-aminomethylated derivatives 164 or to 1-aminomethylated derivatives 165 (fig. 29) , depending on the substituent on n-3 of imidazole ring, and some of these mannich bases had moderate to good antibacterial activity against four common bacteria [236] . aminomethylation and aminoalkylation of saccharin using various types of amine reagents led to mannich bases 166 ( fig. 29 ) with moderate to excellent antibacterial activity against s. aureus (zones of inhibition between 12 and 50 mm, compared to 31 mm for reference drug chloramphenicol) [237] . a note reports in a concise manner the synthesis and antibacterial activity of mannich bases 167 (fig. 29 ) derived from a phenothiazine and primary aromatic amines, and some of the compounds in this study were potent and had a broad spectrum against the tested bacteria [238] . mono-mannich base 168 of quinoxaline-2,3(1h,4h)-dione (fig. 29 ) was screened at concentration of 100 mg/disc, and was found to be more potent than reference drug nalidixic acid at concentration of 50 mg/disc against four common bacteria, with the exception of proteus vulgaris [239] . moderate to good antibacterial activity was determined for mannich bases 169 of 3-aryl-2-thioxo-2,3-dihydroquinazolin-4(1h)one (fig. 29 ), but none of the candidates was as potent as reference drug amikacin against the four common bacteria used in this study [240] . in addition to their anticancer activity evaluation, p-mannich bases 83 (fig. 15 ) were also screened for antibacterial activity, and the mic values were generally approximately 10 mg/ml, regardless of candidate's structure and type of bacteria, but no comparison with reference drugs was provided in the study [106] . a paper claiming the synthesis of s-mannich bases 170 of 4,6-diaryl-2mercaptopyrimidine and secondary aliphatic amines (fig. 29 ) also reports their antibacterial activity weak to moderate, as the most potent candidates are 3-to 7-fold less potent than reference drug ciprofloxacin against four types of bacteria [241] . tuberculosis is a chronic disease whose magnitude and gravity can be gleaned from a 2010 study by world health organization stating that in 2009 alone, 9.4 million new cases of tuberculosis were reported, and 1.7 million deaths were caused by tuberculosis, out of which 0.38 million people were infected with both human immunodeficiency virus and mycobacterium [242] . continuous rise of the number of reported cases of drug-resistant and latent tuberculosis is also alarming and calls for urgent discovery of novel classes of compounds with antimycobacterial activity capable of overcoming the resistance of mycobacterium strains to current drugs. mannich bases are among these novel classes of antimycobacterial compounds that have recently caught the attention of researchers in the field. several examples of papers dealing with antitubercular ketonic mannich bases are available. thus, dimethylamine mannich bases 171 of 2-benzylidenecyclohexanones ( fig. 30 ) were reported to have mic values between 0.39 mg/ml and more than 12.5 mg/ml against mycobacterium tuberculosis h 37 rv (for candidate 171 (n ¼ 0, r 1 ¼ r 2 ¼ h) and candidate 171 (n ¼ 1, r 1 ¼ f, r 2 ¼ h), respectively), which is approximately 20e25% of the efficiency of reference drug rifampin against this microorganism [243] . in addition, the ability of the same candidates to inhibit the growth of mycobacterium avium at concentration of 12.5 mg/ml ranged from 0 to 87%. however, no significant correlations between the structural patterns of mannich bases 171 (e.g., presence or absence of the cinnamoyl double bond, substitution pattern in the phenyl ring, electronic, hydrophobic or steric properties of the substituents in the aromatic ring) and their antimycobacterial activity could be established. mannich base 171 (n ¼ 0, r 1 ¼ och 3 , r 2 ¼ h) emerged from this series as a viable hit compound, having a mic value of 0.78 mg/ml and an ic 50 value for vero cells of 16.4 mg/ml. this compound presents therefore a greater toxicity towards mycobacterium over normal mammalian cells, which has been tentatively explained by its ability to affect respiration in isolated rat liver mitochondria, and had mic values against several drug-resistant strains of mycobacterium that were similar or identical to the values determined for the h 37 rv strain [244] . isocitrate lyase is an enzyme in the glyoxylate cycle that catalyzes the cleavage of isocitrate to succinate and glyoxylate, and, together with malate synthase, bypasses the two decarboxylation steps of the tricarboxylic acid cycle [245] . glyoxylate cycle is essential for the survival of pathogens, including m. tuberculosis, inside the host [246] , and isocitrate lyase has been identified only in bacteria, fungi, and plants, but no analogous enzyme has been documented in humans. therefore, isocitrate lyase has been pursued as a promising target for the development of novel antimycobacterial agents [247] . a high-throughput screening of a large library of ketonic mannich bases against this enzyme led to the identification of candidate 172 (fig. 30 ) with a potent inhibitory activity (ic 50 ¼ 53.5 mg/ml), but this compound's activity against m. tuberculosis has not been actually evaluated [248] . phenolic mannich bases 173 ( fig. 30 ) derived from the hydrazone generated from isoniazid and 2 0 -hydroxyacetophenone were screened against m. tuberculosis h 37 rv, and found to inhibit its growth with mic values ranging from 0.56 to 4.61 mm [249] . six compounds in this series were more potent than isoniazid (mic ¼ 2.04 mm), and the most potent candidate 173 (nr 2 ¼ 1piperazinyl) was shown to be equipotent to isoniazid in decreasing bacterial load in lungs of infected mice at a dose of 25 mg/kg. anti-mycobacterium activity of novobiocin mannich bases 115 (fig. 22) was evaluated, and two of these candidates (nr 2 ¼ n-acetoxyacetyl-n-methyl and n-acetaminoacetyl-nmethyl) showed an increased potency over novobiocin, although no comparison to established antimycobacterial drugs was provided [143] . phenolic mannich bases 174 derived from allomaltol and piperazines (fig. 30 ) had good activity against mycobacterium smegmatis, with mic values between 4 and 16 mg/ml [250] . although the growth inhibition of mycobacterium by the candidates in the library was moderate to good (mic values between 4 and 128 mg/ml), mannich bases derived from 1-phenylpiperazine and its analogues substituted with halogens in the aromatic ring were among the most potent compounds in the series. departure from substitution of piperazine in candidates 174 with bulky, aromatic rings directly linked at n-4 generally led to decreased potency against mycobacterium, although some substituents (such as tbutoxycarbonyl, ethoxycarbonyl, 2-hydroxyethyl, cyclohexyl, benzoyl, furfuryl or 2-(dimethylamino)ethyl) appear to be tolerated better than others (e.g., isopropyl, allyl, 2-methoxyethyl, 2ethoxyethyl, phenethyl or benzyl). an extension of this study, aimed at evaluating against m. tuberculosis h 37 rv the library of mannich bases of type 124 (fig. 23 ) obtained by replacement of piperazines in compounds 174 with piperidines, led to valuable insight on the sar for this particular type of compounds [251] . inspection of the sar in the subset of mannich bases 124 suggested that the position of the substituents and, to a lesser extent, the nature of these substituents plays an important role in their antimycobacterial activity, as the most potent candidates in this subset are generally those substituted at position 4 of piperidine ring [251] . replacement of allomaltol with chlorokojic acid as substrate afforded piperazine mannich bases 125 (r ¼ 4-substituted piperazin-1-yl) (fig. 23) , analogous to both 124 and 174 and having comparable antimycobacterial activity (mic values between 4 and many papers reporting the antimycobacterial activity of mannich bases of pyrrole derivatives have been published in the last decade. the intensive research in this field stems from the discovery by italian researchers at universit a "la sapienza" in rome of bm212 175 (fig. 31) as a potent agent, not only against several collection strains and clinical isolates of m. tuberculosis, but also against non-tuberculosis mycobacterial strains and drug-resistant mycobacteria, with mic values that are comparable to those of reference drugs isoniazid and streptomycin [252] . although the quest for a more potent antimycobacterial agent through systematic modification of lead compound bm212 was not successful at first, it provided experimental proofs for the importance of the presence and nature of substituents at positions 1 and 5 of pyrrole ring [253] . subsequently, novel pyrrole mannich bases 176 analogous to bm212 (fig. 31) , derived from 1-methylpiperazine but also from thiomorpholine as amine reagents, and having either chlorine [254] or chlorine and fluorine [255] as substituents of the phenyl rings in positions 1 and 5 of pyrrole, have been synthesized. two candidates 176 (r 1 ¼ f, r 2 ¼ h or r 1 ¼ h, r 2 ¼ f) showed an improved activity (mic values of 0.4 and 0.5 mg/ml) against m. tuberculosis over mannich base 175 (mic ¼ 0.7 mg/ml) [255] . investigation of structureeantimycobacterial activity relationship in analogues of 175 and 176 was further pursued with a view to optimize the structure of these candidates. thus, synthesis of novel mannich bases of pyrrole using iterative introduction of more lipophilic 1-naphthyl or 2-fluoro-or 2-chlorophenyl moieties at either one of positions 1 and 5 in pyrrole ring of these lead compounds [256] , or a recombination through shuffling of any of the substituents employed so far on the phenyl rings at these two positions of the pyrrole ring [257] was undertaken. these studies confirmed the superior antimycobacterial activity of mannich bases containing a thiomorpholinyl moiety compared to the activity of the corresponding analogues with a 4-methylpiperazinyl moiety, evidenced the importance of fluorine substitution (especially at position 2 of the phenyl ring) for antimycobacterial activity, and proved the decrease of activity with the introduction of 1-naphthyl moieties in the structure of lead compounds 175 and 176. unfortunately, no novel candidates, more potent than mannich bases 175 and 176, have been identified during these investigations. however, replacement of one halogen in the structure of lead compound 175 with more lipophilic substituents (methyl, ethyl n-propyl, i-propyl) afforded candidates with improved antimycobacterial activity (mic values between 0.125 and 0.5 mg/ml) over 175 and even over reference drug streptomycin [258, 259] . in order to further increase the lipophilicity, replacement of the methyl group at position 2 of the pyrrole ring with ethyl was also examined, but these novel mannich bases 177 (x ¼ s or nch 3 ) (fig. 31) were generally less active against several m. tuberculosis strains than their methylsubstituted analogues, although their cytotoxicity towards normal cells was lower than that of the methyl-substituted counterparts [260] . further exploration of the relationship between the nature of substituents on phenyl rings at positions 1 and 5 of pyrrole ring and the antimycobacterial activity of pyrrole mannich bases led to the identification of a novel lead compound 178 (fig. 31) with a very high activity toward both m. tuberculosis 103471 and h 37 rv strains (mic ¼ 0.125 mg/ml) [261] . antimycobacterial activity of mannich base 178 was comparable to that of reference drugs streptomycin or rifampin, while the candidate demonstrated low cytotoxicity towards normal cells (selectivity index ic 50 /mic > 1000) [261] . subsequently a series of morpholine derivatives were designed and synthesized with a view to lower the clearance rate in mouse microsomal fractions associated with the presence of thiomorpholine [262] . although the replacement of thiomorpholine with morpholine generally resulted in a decrease in potency, candidate 179 (fig. 31 ) was found to be equipotent to any of the lead compounds, showed improved microsomal clearance and lower cytotoxicity to normal cells, and was ultimately selected for in vivo pharmacokinetic and efficacy studies in an acute murine tuberculosis infection model. mannich base 179 had an efficacious dose that results in a 99% colony-forming unit reduction in the lung of 49 mg/kg, which is within the range of commonly employed tuberculosis drugs. a recent study showed that mutations in the mmpl3 gene in mycobacterium strains are responsible for resistance to bm212, and suggested that products of this gene are cellular targets for bm212, which makes mmpl3, a member of the mmpl (mycobacterial membrane protein, large) family, a new potential druggable target for the treatment of tuberculosis [263] . point mutations in mmpl3 gene that confer resistance to bm212 and other analogous pyrrole mannich bases have been later identified in several mycobacterium mutants [262] . a large number of antimycobacterial pyrrole mannich bases were also employed to obtain a final multiprobe 3-d qsar model, which was shown to offer good predictions for antimycobacterial activity of an external, unrelated test set of compounds [264] . accounts at various stages of the endeavors concerning the synthesis of pyrrole mannich bases as antimycobacterial agents, along with the related biological results obtained by the italian researchers, have also made the object of several author's reviews along the years [265e268]. a patent claiming the antimycobacterial activity of pyrrole mannich bases derived from 1-arylpiperazines is also worth mentioning [269] . on the other hand, attempts to make a more drastic departure from these already established structural features of antimycobacterial pyrrole mannich bases (such as the introduction of an oxazolidinone moiety reminding of antibacterial linezolid) led to a series of compounds 180 (x ¼ acetamido of 4-(hetero)aryl-1,2,3-triazol-1yl) (fig. 31 ) that were at best 15e65-fold less potent than mannich base 178 [270] . in addition, pyrrole mannich bases 181 (fig. 31 ) were shown to act as inhibitors (ic 50 values ranging from 1.5 to 15 mm) of mycobacterium protein tyrosine phosphatase b, an enzyme that is essential for the survival of bacteria in the host, but no in vitro evaluation using mycobacterium strains was performed [271] . mannich bases of isatin and its derivatives have been evaluated as antimycobacterial agents as well. several isatin mannich bases 182 (fig. 32) containing a semicarbazide moiety were equipotent (mic ¼ 0.625 mg/ml) to isoniazid against m. tuberculosis, and two of the candidates were more potent in vitro than either isoniazid or rifampicin against a multidrug-resistant mycobacterium strain (mic ¼ 6.25 mg/ml) [272] . schiff bases obtained from 5-substituted isatins (r 1 ¼ f, cl, f) and lamivudine were aminomethylated using fluoroquinolones (r 2 ¼ ethyl, cyclopropyl; r 3 ¼ h, ch 3 ) as amine reagents, and the resulting mannich bases 183 (fig. 32) showed 92e100% growth inhibition of m. tuberculosis h 37 rv at a concentration of 6.25 mg/ml; inhibition for one selected schiff base was 82%, and lamivudine alone did not inhibit the growth of this mycobacterium strain at the given concentration [273] . several morpholine mannich bases 184 of 4-substituted thiosemicarbazones of 5-trifluoromethoxyisatin (r ¼ c-c 6 h 11 , 4-fc 6 h 4 , 4-clc 6 h 4 , 4-brc 6 h 4 ) (fig. 32) were potent antimycobacterial agents (mic values between 3 and 5 mg/ml) [274] . replacement of the trifluoromethoxy group in 184 with nitro led to a slight decrease in potency, which became more drastic when fluorine replaced the trifluoromethoxy group, whereas the substitution of morpholine with piperidine generally decreased the antimycobacterial activity of the candidates [275] . using fluoroquinolone gatifloxacin as amine reagent, sixteen mannich bases derived from isatins, isatin semicarbazones, isatin thiosemicarbazones, isatin hydrazones with isoniazid, and isatin schiff bases with sulfadiazine were prepared and tested for antimycobacterial activity [276] . mic values recorded for 90% growth inhibition of mycobacterium by these compounds ranged from 0.78 mg/ml to 12.5 ng/ml, whereas mic values between 0.78 and 0.1 mg/ml were determined for multidrug-resistant strains. promising results were obtained when the most potent compound in this series was tested in a murine model at a dose of 50 mg/kg, and the analysis of data for inhibition of m. tuberculosis dna gyrase suggested that this enzyme could be the target of these isatinefluoroquinolones hybrids. good results were obtained from the evaluation as antimycobacterial agents of mannich bases obtained from 5-substituted isatins and their semicarbazones and thiosemicarbazones as substrates and ciprofloxacin as amine reagent (mic values between 1.2 and 10.3 nm) [277] , and mannich bases generated from 5-substituted isatins, the corresponding semicarbazones, thiosemicarbazones and oxime ethers using 8methoxyciprofloxacin as amine reagent had comparable potencies [278] . analogous mannich bases derived from moxifloxacin as amine reagent were also potent (mic value of 1 mg/ml for m. tuberculosis, and between 4 and 16 mg/ml for multidrugresistant mycobacterium strains), but all of these isatinemoxifloxacin conjugates were generally less potent antimycobacterials than parent fluoroquinolone [279] . evaluation as antimycobacterial agents of aminomethylated 2,3dihydro-1,3,4-oxadiazole-2-ones, 2,3-dihydro-1,3,4-oxadiazole-2thiones and 2,3-dihydro-1,2,4-triazole-3-thiones has led to interesting results. a direct comparison between mannich bases 185 (x ¼ o) of 2,3-dihydro-1,3,4-oxadiazole-2-one and mannich bases 185 (x ¼ s) of 2,3-dihydro-1,3,4-oxadiazole-2-thione (fig. 33) , having both a 4-pyridinyl substituent at position 5 of the azole ring and derived from cyclic secondary aliphatic amines, showed that the former were significantly more potent against an isoniazidsensitive m. tuberculosis h 37 rv strain than the latter, thus suggesting that the presence of oxygen is crucial for the antimycobacterial activity of this type of compounds [280] . in a continuation of the initial study, the search for better antimycobacterial agents was restricted to mannich bases of 2,3dihydro-1,3,4-oxadiazole-2-ones, while the variety of amine reagents employed in aminomethylation was expanded to include n-(substituted benzyl)methylamines, a structural modification that preserved the good activity of the candidates (mic values of 4e8 mg/ml) [281] . however, replacement of the 4-pyridinyl substituent at position 5 of mannich bases 185 (x ¼ o) with phenyl, 3pyridinyl of pyrazinyl resulted in a significantly decreased antimycobacterial activity, whereas replacement with 2-pyridinyl did not generally affect the activity of the candidates. bis-mannich bases 186 (fig. 33 ) derived from dapsone as amine reagent, benzaldehyde and furan-2-carboxaldehyde as aldehyde reagents and variously 5-substituted 1,3,4-oxadiazole-2-thiones as substrates had excellent antimycobacterial activities against both isoniazidsensitive and isoniazid-resistant strains of m. tuberculosis, as they were 5-fold more potent than isoniazid against the sensitive strain and 10-fold more potent than isoniazid against the resistant strain [282] . a study allowed another direct comparison, this time between mannich bases 139e of 2,3-dihydro-1,3,4-oxadiazole-2thiones ( table 2) and mannich bases 134i (table 1 ) of 2,3dihydro-1,2,4-triazole-3-thiones having the same 4isopropylthiazole-2-yl substituent at position 5 of the aforementioned azoles. some of candidates 134i were 2-to 4-fold more potent than the most potent mannich base 139e against m. tuberculosis h 37 rv strain, but they were still 16-fold less potent than isoniazid [187] . on the other hand, mannich bases 187 (r 1 ¼ h, oh; r 2 ¼ c 2 h 5 , ch 2 ch]ch 2 , c 6 h 5 , 4-brc 6 h 4 ; r 3 ¼ ch 2 c 6 h 5 , c 6 h 5 , substituted phenyl, 2-pyrimidinyl) derived from 1,2,4-triazole-3thiones (fig. 33 ) had low antimycobacterial activity (mic values between 25 and 100 mg/ml) [283] . the majority of mannich bases derived from either 2,3-dihydro-1,2,4-triazole-3-thione or 2,3dihydro-1,2,4-triazole-3-one having a 3-pyridinyl moiety at position 5 of the triazole ring were more potent antimycobacterials (mic between 16 and 32 mg/ml) than reference drug streptomycin against m. smegmatis [175] . in addition, 2,3-dihydro-1,2,4-triazole-3-one mannich base 137 (nr 2 ¼ 1-piperidinyl) (fig. 25 ) was equipotent to reference drug streptomycin (mic ¼ 4 mg/ml) against m. smegmatis [192] . mannich bases 188 of imidazo[2,1-b]-1,3,4-thiadiazole derivatives ( fig. 34 ) have been screened for antimycobacterial activity. evaluation of a library of mannich bases 188 (r 1 ¼ c-c 6 h 11 , 2-furyl, 2-thienyl; r 2 ¼ h, br; nr 2 ¼ 1-pyrrolidinyl, 1-piperidinyl, 4morpholinyl) against m. tuberculosis h 37 rv showed that all of the candidates had mic >6.25 mg/ml [284] , but a second collection of aminomethylated imidazo[2,1-b]-1,3,4-thiadiazole derivatives 188 (r 1 ¼ n-c 3 h 7 , c-c 6 h 11 , 2-thienyl; r 2 ¼ cl, ch 3 , och 3 ; nr 2 ¼ 1-pyrrolidinyl, 1-piperidinyl, 4-morpholinyl) consisted of mannich bases with good antimycobacterial activity (52e99% growth inhibition) at a concentration of 6.25 mg/ml [285] . amongst mannich bases 188 (r 1 ¼ 4-ch 3 oc 6 h 4 ch 2 ), pyrrolidine-containing derivatives were consistently the best agents against m. tuberculosis h 37 rv [286] . also, compounds 155 (nr 2 ¼ 1-pyrrolidinyl, 1-piperidinyl, 4morpholinyl) (fig. 29 ) had moderate antimycobacterial activity (mic ¼ 25 mg/ml) [226] . in addition to the types of substrates presented so far, miscellaneous other substrates have been subjected to the mannich reaction with a view to synthesizing compounds with antimycobacterial activity. aminomethylation of the amide function in tetracyclines using fluoroquinolones as amine reagents afforded mannich bases 189 (fig. 34) with excellent activity against m. tuberculosis (mic values between 0.2 and 1.56 mg/ml) [287] . pyrazinamide was also aminomethylated at the amide function using piperazines (including four fluoroquinolones) as amine reagents; the resulting mannich bases 190 (fig. 34) were at least as potent as reference drug pyrazinamide against m. tuberculosis, and showed a significantly improved antimycobacterial activity over pyrazinamide against multidrug-resistant mycobacterium strain [288] . anti-hiv drug efavirenz was aminomethylated using either common piperazines or piperazine-containing fluoroquinolones as amine reagents to afford hybrids 191 (fig. 34) , but only the mannich bases derived from fluoroquinolones had good activity against m. tuberculosis (no comparison with standard antimycobaterial drugs was available though) [289] . investigation of antimycobacterial activity of a small number of indole mannich bases 59 obtained from 1-arylpiperazines (fig. 11 ) uncovered a few candidates that inhibited the growth of m. tuberculosis h 37 rv almost completely at a concentration of 6.25 mg/ml [290] . 159 (fig. 29 ) had good antimycobacterial activity (mic < 5 mg/ml) [230] , while mannich base 168 (fig. 29 ) was moderately active against m. tuberculosis h 37 rv [239] . finally, pyrazolone mannich base 161 (nr 2 ¼ nhcoc 6 h 5 ) (fig. 29 ) was more potent than reference drugs ethambutol and ciprofloxacin, but inferior to isoniazid, against m. tuberculosis h 37 rv [232] . the incidence of fungal infections of any variety has been steadily increasing over the last decades, and it has become one of the main causes of morbidity and mortality, especially in patient with compromised immune systems [293] . development of resistance to currently-in-use antifungal drugs also represents a major concern, and the discovery of novel antifungal agents, preferably outside any of the six major classes that are presently available for treatment, is one of the highest priorities for pharmaceutical industry. the latest advances in the evaluation of mannich bases with various structures as potential antifungals are presented in this section. first reports on the antifungal activity of ketonic mannich bases are relatively recent. a few mono-mannich bases of type 8 (fig. 3) and double mannich bases 12 (fig. 4 ) of acetophenone (r 1 ¼ r 2 ¼ h; nr 2 ¼ dimethylamino, 1-piperidinyl, 4-morpholinyl) have been shown to have weak antifungal activity, but the corresponding methiodides were more potent than reference drug amphotericin b against yeasts saccharomyces cerevisiae and candida krusei, and against dermatophytes trichophyton mentagrophytes, trichophyton rubrum and microsporum canis [294] . thus, quaternization of the nitrogen atom in mannich bases of type 8 appears to be a chemical modification leading to efficient antifungals [135] . various substitution patterns in the phenyl ring in ketonic mannich bases 8 also did not improve significantly the antifungal activity of these compounds [295] . bis-mannich bases 13 (r ¼ c 2 h 5 ) derived from various acetophenones (fig. 4) were only active against aspergillus fumigatus, but the antifungal activity of the related piperidinols 14 (r ¼ c 2 h 5 ) (fig. 4) was broader and slightly more potent compared to that of corresponding mono-mannich bases 8 and bis-mannich bases 13, especially against dermatophytes t. rubrum and m. canis [295] . however, a later study showed that a minor modification such as replacement of ethyl with methyl as substituent at nitrogen increased the antifungal activity of bis-mannich bases 13 (r ¼ ch 3 ), while it decreased the potency of piperidinols 14 (r ¼ ch 3 ) against t. rubrum and m. canis [296] . use of phenethylamine as amine reagent in the mannich reaction with various acetophenones afforded secondary ketonic mono-mannich bases 15 (r ¼ ch 2 ch 2 c 6 h 5 ) (fig. 4) along with piperidinols 14 (r ¼ ch 2 ch 2 c 6 h 5 ), but these compounds had relevant activity (most mic values were either 12.5 or 25 mg/ml) only against m. canis, a dermatophyte whose growth was not inhibited by reference drug nystatin in the concentration range used in this study [297] . most members of a library of mannich bases 10 of enones had antifungal effects 2e16-fold more potent than amphotericin b against at least one (if not many) selected plant fungi [298] . ketonic mannich bases derived from arylamines as amine reagents have also been reported to have antifungal effects. thus, mannich bases 108 (r 1 ¼ 2-br, r 2 ¼ h or f) (fig. 21) were almost twofold more potent than reference drug ampicillin against candida albicans [137] , whereas candidates 109 (r ¼ f or cl) derived from 3-acetylcoumarin and 110 (r ¼ cl or n(ch 3 ) 2 ) derived from 2-acetylbenzofuran (fig. 21) had mic values comparable to those of reference drug fluconazole against aspergillus flavus, chrysosporium keratinophilum, and c. albicans [138] . evaluation of mannich bases 194 (fig. 35 ) derived from cyclic ketones (n ¼ 1e4) showed that these compounds had good anti-candida and anti-saccharomyces activity, but they were less potent against aspergillus strains, and none of the compounds were as potent as reference drug amphotericin b [299] . the anti-candida potency of candidates 194 generally diminished with the increasing size of the ring, while the substitution pattern of the aromatic ring or the nature of the amine in the aminomethyl moiety did not influence the antifungal activity considerably. in addition, the a,bunsaturated ketone system is a structural requirement for the antifungal activity of mannich bases 194, as the amino alcohols obtained through the reduction of the carbonyl group in 194 were mostly inactive towards all the fungi used in this study. inhibition of ergosterol synthesis does not appear to be the mechanism by which mannich bases 194 exert their anti-candida activity, although they are able to influence the development of pseudohyphae and induce noticeable changes in the protein composition in c. albicans [299] . inspection of sar disclosed in the previous study also proved valid for mannich bases 195 derived from cyclic ketones fused with an aromatic ring (fig. 35) , except that the mic values for compounds 195 were consistently better than those for mannich bases 194 [300] . transcript profiling of c. albicans cells treated with candidate 195 (n ¼ 0, nr 2 ¼ 4-morpholinyl) showed that the transcriptional response is typical for oxidative stress and similar to that of a c. albicans cap1 transcriptional activator, which suggests that the ability of mannich bases 195 to directly trigger oxidative stress may be at least in part the reason for their antifungal activity [300] . mannich bases 196 of thiocroman-4-ones (fig. 35) obtained either from secondary aliphatic amines or from primary arylamines had good activity against several types of fungi, and two candidates 196 (nr 1 r 2 ¼ n(ch 3 ) 2 , r 3 ¼ 6-cl, r 4 ¼ 5-f or 8-cl) were more potent than reference drug ketoconazole against the fungi investigated in the study [301] . antifungal activity of double mannich bases 105 (fig. 21) against several fungi was also good, although the potency of compounds 105 against c. albicans was only moderate [134] . several studies reporting the antifungal activity of phenolic mannich bases are available. the hydrazone obtained from 2,4dinitrophenylhydrazine and salicylaldehyde was aminomethylated using various secondary amines to give mannich bases 197 (fig. 36 ) [302] the most potent anti-candida candidates 197 (nr 2 ¼ diphenylamino, 4-morpholinyl, 1-piperazinyl) were 5e10fold weaker than reference drug clotrimazole, whereas the growth of aspergillus niger was inhibited by the most potent compounds at mic values in the range of 1.56e3.12 mg/ml [302] . most aminomethylated 4-t-butylcatechols 113 (fig. 22) , along with their copper(ii) complexes, have significant antifungal activity (radial inhibition of mycelial growth ! 70%) against several plant pathogenic fungi, which is comparable, or even higher in a several cases, to that of reference drugs nystatin and terbinafine [141] . even at a concentration 10-fold greater than that of reference drug voriconazole, only three of mannich bases 114 (nr 1 r 2 ¼ 4methoxyphenylamino, 1-piperidinyl, 4-methylpiperazinyl) (fig. 22 ) barely showed anti-candida activity that was comparable to that of voriconazole [142] . aminomethylation of mulundocandin, an antifungal lipopeptide belonging to echinocandin antifungals, was undertaken with a view to improve its solubility in water; the resulting mixture of mannich bases 198 (r 1 ¼ ch 2 nr 2 , r 2 ¼ h) and double mannich bases 198 (r 1 ¼ r 2 ¼ ch 2 nr 2 ) (fig. 36) was separated before the antifungal activity of the compounds was evaluated in vitro, but only one candidate showed good inhibition against c. albicans and a. fumigatus [303] . nonetheless, in vivo testing of the collection was promising, as many compounds showed anti-candida activity comparable to parent mulundocandin, while a significant improvement in anti-candida activity compared to mulundocandin was observed for mono-mannich base 198 (r 1 ¼ 4-phenylpiperazinylmethyl, r 2 ¼ h), which was equipotent to fluconazole. three members of a collection of 6acetyl-1,3-benzoxazines 117 (r 1 ¼ ch 3 , r ¼ 4-br; r 1 ¼ h, r ¼ 2-och 3 or 4-f) (fig. 22 ) had inhibition zones against a. niger comparable to that of reference drug fluconazole [145] . benzoxazines 118 and 119, as well as naphthoxazines 120 and 121 (fig. 22) were either inactive or had weak activity against candida spp., a. fumigatus and cryptococcus neoformans, but a few compounds in this library had moderate activity against sporothrix schenckii and t. mentagrophytes [146] . in contrast, naphtho[2,1-e]-1,3-oxazine 121 (r ¼ 4-c 2 h 5 oc 6 h 4 ) was more potent than reference drug griseofulvin against c. albicans, whereas naphtho[2,1-e]-1,3oxazine 121 (r ¼ 3-ch 3 oc 6 h 4 ) was equipotent to griseofulvin against a. niger [148] . examples of mannich bases from phenols fused with heterocyclic rings that were investigated for antifungal activity include compounds 123 (fig. 22) , which had only moderate to weak activity against a. niger and penicillium spp. compared to reference drug griseofulvin [150] , and compounds 122 (fig. 22) , which were efficient against aspergillus spp. and c. albicans at concentrations as high as 5 mg/ml [149] . mannich bases 125 of chlorokojic acid (fig. 23) had good anti-candida activity (mic values between 4 and 16 mg/ml) [152e154], but the antifungal activity against dermatophytes was slightly poorer [304] . in contrast, mannich bases 174 (fig. 30) derived from allomaltol and 4substituted piperazines had poor antifungal activity against c. albicans and candida parapsilosis compared to that of reference drug fluconazole, but some members of the library were equipotent to fluconazole against c. krusei [305] . antifungal activity of various mannich bases of isatin derivatives has been examined jointly with their antibacterial activity. mannich bases 127 (fig. 24 ) obtained from isatin semicarbazone as substrate and (hetero)arylamines as amine reagents had good anti-candida activity (75e87% of the activity of reference drug fluconazole) [156] , whereas mannich bases 128 (r ¼ secondary aliphatic amines) (fig. 24 ) had moderate antifungal activity against aspergillus spp., and consistently lower than that of reference drug fluconazole [157] . for the most active mannich bases 129 (r 1 ¼ 4-or 4,5-substituted 2-ethylphenyloxy, r ¼ 1-piperidinyl or 4morpholinyl), the antifungal potency against c. albicans and a. niger was 2/3 of the potency of reference drug griseofulvin [159] . a couple of mannich bases 130 (r 1 ¼ substituted phenyl) (fig. 24) were moderately active against a. niger, but the activity against c. albicans and penicillium notatum was generally poor [160] . mannich bases 131 (r 1 ¼ 5-benzyl-3-thioxo-2h-1,2,4-triazol-4-yl) (fig. 24) were moderately potent against c. albicans and a. niger compared to reference drug fluconazole [163] . finally, in their evaluation against a. niger, mannich base 132 (ar ¼ c 6 h 4 oh-4) (fig. 24 ) was equipotent to reference drug ketoconazole against a, fumigatus, whereas mannich base 132 (ar ¼ c 6 h 4 n(ch 3 ) 2 -4) was twofold more potent than ketoconazole, and three other analogues were equipotent to ketoconazole [164] . evaluation of mannich bases of 2,3-dihydro-1,2,4-triazole-3thiones (table 1) as antifungal agents has been reported in conjunction with their antibacterial activity. in the series of mannich bases 133a, with the exception of candidate 133a (r ¼ c 6 h 4 cl-4, nr 2 ¼ nhc 6 h 3 f 2 -2,6) whose anti-candida activity was 2/3 of that of reference drug clotrimazole, all other compounds were inactive, and so were mannich bases 133b investigated in the same study [165] . compared to reference drug fluconazole, most active mannich bases 133h were 3-fold less potent against c. albicans and s. cerevisiae [173] , mannich bases 133j were either inactive or showed low antifungal activity [175] , whereas mannich bases 133k were inactive against c. albicans and s. cerevisiae [176] . mannich bases 133i lacked any anti-candida activity [174] , as did mannich bases 133n and 133o [179] , and most mannich bases 133q [180] . the majority of mannich bases 134a were equipotent to reference drug fluconazole against c. albicans [181] , and a small number of candidates 134c were moderately active against the same fungus, whereas the rest were inactive [182] . while most mannich bases 134d were moderately active against aspergillus spp., c. albicans and penicillium marneffei, two candidates 134d (r 2 ¼ 4-clc 6 h 4 or 2,4-cl 2 c 6 h 3 ) derived from 1-methylpiperazine as amine reagent were equipotent to reference drug ciclopiroxolamine [183] . several mannich bases 134e were also equipotent to reference drug fluconazole against aspergillus spp., t. mentagrophytes and p. marneffei [184] . neither compound 134g, nor candidate 135 (fig. 25 ) exhibited any anti-candida activity [185] , whereas mannich bases 134i had weak to moderate activity against candida tropicalis, s. cerevisiae and a. niger [187] . the antifungal activity of mannich bases 134j against aspergillus spp. and penicillium spp. was moderate to good, and mannich base 134j (x ¼ y ¼ ch 3 , r 2 ¼ 4-no 2 c 6 h 4 ) was more potent than reference drug fluconazole against c. albicans [188] . a few mannich bases 134k also showed good antifungal activity against c. albicans and fusarium solani [189] . the best anti-candida activity in the series of mannich bases 134m was recorded for the candidate with r 2 ¼ c 6 h 4 och 3 -4 (85% of the inhibition zone of reference drug fluconazole) [190] . in addition, 1,2,4-triazolo[5,1-b]-1,3,5-thiadiazines 199 (fig. 36) have been synthesized through a double mannich reaction starting from 5-benzyl-2h-1,2,4-triazole-3(4h)-thione and primary aliphatic and aromatic amines, and these compounds had good antifungal activity against chrysosponium tropicum and t. rubrum, but were completely inactive against a. fumigatus, a. flavus and microsporum nanum [306] . mixed results were obtained for other fungi, as a few candidates 199 were more potent than reference drug clotrimazole against a. niger, but were moderately potent against c. albicans or fusarium oxysporum, whereas the rest of the compounds in the series were totally inactive against these three fungi. as far as the aminomethyl derivatives of 2,3-dihydro-1,2,4-triazole-3-ones are concerned, candidates 136 and 138 (fig. 25 ) had no activity against c. albicans and s. cerevisiae [176, 191] , whereas in the series of mannich bases 137 featuring an imidazole moiety (fig. 25) , candidate 137 (nr 2 ¼ 1-piperidinyl) was twofold more potent against s. cerevisiae and twofold less potent against c. albicans than reference drug fluconazole [192] . antifungal activity of aminomethylated 2,3-dihydro-1,3,4oxadiazole-2-thiones ( table 2 ) has been reported in the same studies dealing with these compounds' antibacterial activity. several mannich bases 139a were equipotent to reference drug ciclopiroxolamine against t. mentagrophytes, a. flavus and a. fumigatus (mic 6.25 mg/ml), but not against p. marneffei [193] . mannich bases 139b derived from either morpholine or 3trifluoromethylaniline showed high activity against p. marneffei, t. mentagrophytes, a. flavus and a. fumigatus compared to reference drug ciclopiroxolamine, whereas those derived from other primary aromatic amines had only weak antifungal activity [194] . only a few of mannich bases 139c derived from piperazines had moderate anti-candida activity, and the rest of the collection was inactive [195] . oxadiazolethione mannich bases 139d [185] and 139j [176] , having at position 5 of the oxadiazole ring either a pyridine or a quinoline moiety, had no noticeable anti-candida activity, and the activity of mannich bases 139e against s. cerevisiae, c. tropicalis and a. niger was moderate at best [187] . most mannich bases 139f had weak antifungal activity against c. albicans, a. niger and aspergillus clavatus, but one candidate 139f (nr 2 ¼ nhc 6 h 4 och 3 -4) was 2-fold more potent than reference drug ketoconazole against the first two fungi, and almost equipotent to ketoconazole against the last fungus [196] . several mannich bases 139g had similar mic values as reference drug amphotericin b against c. albicans, a. fumigatus, t. rubrum and t. mentagrophytes [197] . most imidazole-containing mannich bases 139h exhibited better antifungal activity against c. albicans, t. rubrum and t. mentagrophytes than reference drug fluconazole [198] . the compounds reported in a study, including mannich bases 139i, are claimed to exhibit significant antifungal activity against c. albicans, but lack of access to the original information (which is only provided in the online edition as supplemental material, and is missing) makes data assessment impossible [199] . three mannich bases 139k were moderately active against aspergillus spp. and curvularia lunata [200] , while mannich bases 139l [98] and 139o [202] had no anti-candida activity, and mannich base 139m showed no antifungal activity against c. albicans and s. cerevisiae [201] . in addition, several aminomethylated 2,3dihydro-1,3,4-oxadiazole-2-ones 141 were more potent than reference drug nystatin against fungal plant pathogens aspergillus spp. ( [204] . anti-candida activity of c-mannich bases 142 of thiazolidinone (fig. 26 ) was found to be 16-fold weaker than that of reference drug terbinafine [205] . while three mannich bases 143 were moderately active against c. albicans and a. flavus, one candidate 143 (r 1 ¼ c 6 h 5 , nr 2 ¼ n(c 2 h 5 ) 2 ) (fig. 26) showed against the latter fungus a growth inhibition potency (mic ¼ 1.56 mg/ml) which was half of that determined for reference drug fluconazole [207] . also, aminomethylated thiazolidinones 144 (fig. 26) had moderate activity against aspergillus spp. and c. albicans compared to reference drug ketoconazole [208] . pyrimidine derivatives that have been aminomethylated with a view to evaluate the antifungal activity of the resulting mannich bases include pyrimidin-2-ones, pyrimidin-2-thiones and (thio) barbituric acid. double n-mannich bases 146 (x ¼ o or s) (fig. 26) had 67e77% of the anti-candida activity of the clotrimazolecontaining commercial drug imidil [210, 211] . c-mannich bases 200 of (thio)barbituric acid (fig. 37) , obtained using furan-2carboxaldehyde or indole-3-carboxaldehyde as aldehyde components and 2-aminopyridine or 4-aminoantipyrine as amine reagents in the mannich reaction, showed good activity against aspergillus spp. compared to reference drug salicylic acid [307] . antifungal evaluation of mannich bases from miscellaneous substrates that do not belong to any of the previously mentioned classes is the topic of several studies. p-mannich bases 83 (fig. 15 ) showed good activity against c. albicans and s. cerevisiae (mic ¼ 10 mg/ml) compared to reference drug amphotericin b (mic ¼ 15 mg/ml) [106] . various mannich bases of type 149 (fig. 27) derived from imides presented anti-aspergillus activity that ranged from weak to good, but no correlations between structure and activity for the small number of compounds in this series could be established [215] . anti-candida activity of the most potent mannich bases 152 (fig. 29 ) was only half of the activity of reference drug fluconazole [222] . aminomethylated hydrazidones 153 (r 1 ¼ c 2 h 5 ) derived from isonicotinic acid hydrazide (fig. 29 ) had good anti-candida activity [223] , but their analogues 153 (r 1 ¼ n-c 3 h 7 ) were less active, and their activity against a. niger was even poorer [224] . several dimethylamine mannich bases 154 derived from 7-methyl-2-(substituted aryl)imidazo[1,2-a]pyridines (fig. 29 ) were 4-folde2-fold more active against aspergillus spp. and c. albicans than reference drug griseofulvin [225] . when evaluated against the same fungi, mannich bases 157 (r 1 ¼ ch 3 ) and 158 of sydnones (fig. 29) were consistently less active than both reference drugs griseofulvin and nystatin [228] , and the majority of mannich bases 157 (r 1 ¼ och 3 ) behaved similarly, with the exception of candidate 157 (r 1 ¼ och 3 ; nr 2 ¼ 4-nitrobenzothiazole-2-ylamino), which was more potent than reference drugs fluconazole and nystatin against c. albicans [229] . all of the mannich bases 156 derived from 2-alkyl-3-hydroxy-pyridine-4(1h)-ones (fig. 29) were inactive against aspergillus spp. and c. albicans [227] . a few aminomethylated pyrazolines 159 (fig. 29 ) had anti-candida activity (mics between 1.5 and 4 mg/ml) comparable or even better than that of reference drug clotrimazole (mic ¼ 2 mg/ml) [230] , while several acetylenic mannich bases 162 (fig. 29 ) were equipotent to reference drug ketoconazole against c. albicans [233] . mannich bases 164 and 165 derived from hydantoins ( fig. 29) were generally moderate growth inhibitors for c. albicans and a. niger [236] , and phenothiazine mannich bases 167 (fig. 29) were all active against a. niger (sizes of inhibition zone between 12 and 21 mm) [238] . antifungal activity of mannich base 168 (fig. 29 ) of quinoxaline-2,3(1h,4h)-dione (100 mg/disc) against c. albicans and a. niger was superior to that of reference drug clotrimazole (50 mg/disc) [239] , while antifungal activity of mannich bases 169 of 3-aryl-2-thioxo-2,3-dihydroquinazolin-4(1h)-one (fig. 29) equipotent to reference drug fluconazole against c. albicans (mic 6.25 mg/ml) [240] . as much as 20% of the world population live in areas with high risk of contracting malaria, and millions of people suffer from acute malaria each year, while approximately half million died from the disease in 2012 [308] . malaria has been largely eradicated in many parts of the world, but the total number of recorded cases is still on the rise. one of the causes for this grave situation is the proliferation of malaria parasites that are rapidly becoming resistant to antimalarial drugs, especially those that are most frequently used, such as chloroquine. the development of novel antimalarials has stagnated since the 1970s owing to lack of interest in developed countries for this topic, and limited market potential for these drugs. initiation of numerous programs supported by public funding led to a surge of interest in drugs for neglected diseases, and antimalarials are certainly amongst these drugs. use of the mannich reaction for the synthesis of antimalarials has a long and rich history, the quest for aminomethylated substrates for treatment of malaria starting with amodiaquine 201 (fig. 38) , the first mannich base that was used to treat malaria. many of these early studies focused on derivatives of 4aminoquinolines, and the sar within this class of antimalarials suggested that the chlorine atom at position 7 of the quinoline scaffold and the phenolic mannich bases moiety are structural features that are essential for the antimalarial activity of these compounds. nowadays, the use of amodiaquine has declined owing to its considerable toxicity as a result of its in vivo conversion into a reactive quinone-imine metabolite by cytochrome p450. it was therefore hypothesized that swapping the phenolic hydroxyl and the aminomethyl side chain in amodiaquine should prevent the formation of toxic metabolites, and help circumvent the adverse side effects associated with the use of amodiaquine. this hypothesis led to the design and synthesis of several amodiaquine analogues that retain the antimalarial activity, while lacking the potential to form a quinone-imine derivative [309] . out of these analogues, mannich base 202 (the isomer of amodiaquine henceforth named isoquine, fig. 38 ) expressed in vitro activity against both chloroquine sensitive hb3 strain and highly chloroquine-resistant k1 strain of plasmodium falciparum below 10 nm, and was 20 times more potent that chloroquine. isoquine (as its diphosphate salt) was subsequently tested in vitro against the murine plasmodium yoelii ns strain, and found to be 3-fold more potent than amodiaquine when administered orally. moreover, no toxic metabolites or any excessive accumulation of isoquine have been noticed in animal models, but unacceptably high first pass metabolism of isoquine to n-dealkylated metabolites in four animal species compromised isoquine's activity against parasites, and complicated the development process of isoquine into a marketable drug. a novel candidate, n-tert-butyl isoquine (gsk369796) 203 (fig. 38) , was identified using isoquine as lead, and shown to exhibit low nm activity against chloroquine-resistant and sensitive parasites, as well as in vivo oral activity equivalent to amodiaquine, but with a significantly improved antimalarial exposure profile [310] . in addition, n-tert-butyl isoquine had a better overall preclinical safety profile than chloroquine or amodiaquine, and can be synthesized in a scalable and cost-effective way. the study of disposition of candidates 202 and 203 showed that isoquine 202 undergoes in vivo oxidative n-dealkylation to desethyl-isoquine, a metabolite that had an improved blood clearance over isoquine; unfortunately, desethyl-isoquine also had a more potent inhibitory action of cyp1a2 than isoquine [311] . on the other hand, n-tertbutyl isoquine 203 had human plasma protein binding ability and inhibition of cyp2d6 similar to those of isoquine and desethylisoquine, but a reduced rate of n-dealkylation and a higher oral bioavailability compared to isoquine and desethyl-isoquine, and these properties made n-tert-butyl isoquine 203 a better candidate than isoquine 202 for further development. a study of the in vitro activity of isoquine 202 against p. falciparum clinical isolates collected in kenya in relation to amino acid changes in pfcrt and pfmdr1, the two genes associated with 4-aminoquinoline resistance, showed that isoquine possesses high activity against field isolates (ic 50 was 9 nm, compared with 56 nm for chloroquine, and 8 nm for amodiaquine), and that isoquine's activity could be correlated with polymorphisms in pfcrt, but not in pfmdr1 [312] . starting from n-tert-butyl isoquine 203 as a template, three benzoxazines 204 (r ¼ c 2 h 5 , n-c 3 h 7 , ch 2 c 6 h 5 ) (fig. 38 ) were designed and generated through a double mannich reaction, but despite the good anti-plasmodium activity against both chloroquine-sensitive (ic 50 between 21 and 38 nm) and chloroquine-resistant (ic 50 between 31 and 72 nm) strains, the rapid ring opening of benzoxazine at low ph makes them unsuitable for further development [313] . novel analogues 205 (nr 2 ¼ aliphatic primary and secondary amines, aromatic primary and secondary amines) of amodiaquine have been tested in vitro against chloroquine-sensitive strains of p. falciparum, and while all of the compounds were active, only mannich base 205 (nr 2 ¼ 4morpholinyl) (fig. 38 ) showed good activity (mic ¼ 63 ng/ml) compared to chloroquine (mic ¼ 250 ng/ml) [314] . antimalarial activity of analogues 206 of isoquine (fig. 38) has also been evaluated, but regardless of the nature of the amine in the aminomethyl moiety, their activity was considerably lower than that of reference drug chloroquine [315, 316] . use of primary amines derived from bicyclic scaffolds for the synthesis of novel isoquine analogues led to the discovery of 207 (fig. 38) , which was approximately twofold more potent that either chloroquine or isoquine against chloroquine-sensitive and resistant p. falciparum strains [317] . a series of isotebuquine analogues 208 (r ¼ cl or cf 3 , r 1 ¼ h), the corresponding double mannich bases 208 (r 1 ¼ ch 2 nhc(ch 3 ) 3 ), as well as n-oxides derived from a mono-mannich base and a double mannich base of type 208 (fig. 38) were also evaluated against chloroquine-sensitive and resistant p. falciparum strains [318] . while only a few of candidates 208 were more potent than chloroquine against the chloroquine-sensitive strain, the majority of these mannich bases were more potent than chloroquine against the chloroquine-resistant strain, and mannich bases having one aminomethyl function were generally more potent than double mannich bases. pyronaridine 209 (fig. 39) is another example of antimalarial drug that feature a phenolic mannich bases moiety in its structure, but the aminoquinoline scaffold that was typical for amodiaquine and its congeners has been replaced in pyronaridine by a naphthyridine ring system. pyronaridine was first synthesized in 1970 at the chinese institute of parasitic disease, and has been used solely in china as treatment for malaria with good results for over 30 years [319] . beside the difficultly accessible literature in chinese, there are several recent studies that provide information on its physicochemical properties [320] and adme properties in rats [321] , interaction with other antimalarials [322] , potential use in combination therapy with artesunate [323] , or its mechanism of action based on inhibition of b-hematin formation and subsequent glutathione-dependent hematin degradation process [324] . based on the observation that substitution of the quinoline scaffold in amodiaquine with a napthyridine ring system in pyronaridine preserved the antimalarial action, g€ orlitzer initiated an ambitious synthetic program aiming at exploring the effect on the antimalarial properties of replacement of quinoline in quinoline-based antimalarials with other fused heterocyclic systems containing one pyridine ring. thus, single (r 1 ¼ h) and double mannich bases (r 1 ¼ ch 2 nr 2 ) structurally related to amodiaquine and pyronaridine, respectively, and featuring pyrido[3,2-b]indol-4-yl (compounds 210, x ¼ nh) [325] , benzofuro [3,2[1, 6] naphthyridin-5-yl (compound 215) [332] moieties were synthesized and evaluated against chloroquine-sensitive and resistant p. falciparum strains (fig. 39) . as expected, all of the mannich bases presented in these studies exhibited good antimalarial activity, and double mannich bases were generally more potent than single mannich bases. however, in spite of the variety of fused heterocyclic systems that were investigated, no compound with antimalarial activity at least comparable to that of chloroquine emerged, with the exception of one pyronaridine analogue (210, x ¼ nh, r 1 ¼ ch 2 nr 2 , nr 2 ¼ 1-pyrrolidinyl). this candidate had ic 50 ¼ 50 nm against chloroquine-sensitive strain 3d7, ic 50 ¼ 38 nm against chloroquine-resistant strain dd2, and its evaluation against plasmodium winckei in a murine malaria model (intraperitoneal dosage of 100 mg/kg) showed that no intact parasite could be noticed after three days of treatment [325] . the phenolic mannich base moiety in the previously mentioned antimalarial agents can be also found in candidates that were designed through its incorporation into hybrids with dual mode of action. thus, the combination of a tetraoxane and a phenolic mannich base moiety afforded hybrids 216 called mannoxanes (fig. 40) , which are active at low nanomolar concentrations and surpass the ability of artesunate, tetraoxane rka 182 and a peroxide/amodiaquine combination to cure malaria in mice at 10 mg/kg [333] . hybridization of artemisin with a phenolic mannich base moiety led to candidates 217 (fig. 40) , which are up to 3 times more potent than artemisin against p. yoelii nigeriensis, could be easily converted into water soluble forms, can be administered orally, are presumed to have good bioavailability, and lack the capability to form neurotoxic metabolite dihydroartemisinin [334] . hybrids 218 (fig. 40 ) are structurally very similar to 217, and have been shown to be more active than sodium artesunate against chloroquine-sensitive nf54 and chloroquine-resistant k1 p. falciparum strains [335] . screening of a collection of compounds containing a 2-hydroxyethylamino motif in their structures for inhibition of parasite growth in red blood cells infected with chloroquine-sensitive nf54 p. falciparum strain identified a hit compound, whose further elaboration led to several hybrids featuring several types of phenolic mannich moieties as the second pharmacophore [336] . their evaluation against nf54 strain, k1 strain, and the rodent parasite plasmodium berghei showed that the introduction of the phenolic mannich bases moiety resulted in candidates that were very potent against the parasites in the 72 h assay. for example, compound 219 (fig. 40) the design of hybrids with dual mode of action has also been broadened to include pyrrole mannich bases. thus, hybrids 220 from 4-amino-7-chloroquinoline and pyrrole mannich bases (fig. 40) were evaluated against chloroquine-sensitive d10 and chloroquine-resistant w2 p. falciparum strains, but they were all less potent than isoquine against both strains [317] . however, candidate 220 (r 1 ¼ 4-clc 6 h 4 , nr 2 ¼ n(c 2 h 5 ) 2 ) was equipotent to chloroquine against d-10 strain, and four of the candidates were also more potent than chloroquine against w2 strain [317] . several candidates from a small library of mannich bases 221 (r 1 ¼ h or ch 3 ) of c-10 pyrrole analogues of artemisin (fig. 40 ) had antimalarial activity that was superior to both artemisin and chloroquine against chloroquine-sensitive 3d7 p. falciparum strain, and selected mannich bases from this library were more potent than the aforementioned reference drugs against chloroquine-resistant k1 p. falciparum strain [337] . all of the compounds tested displayed good activity in peter's 4 day suppressive test using 30 mg/kg over days 1e3 post-infection, and candidates 221 ( showed complete elimination of parasites. these three mannich bases were further investigated in vivo, and had effective doses between 4.3 and 5.3 mg/kg that eliminate 90% of p. berghei in mice, whereas candidate 221 (r 1 ¼ ch 3 , nr 2 ¼ 4methyl-1-piperazinyl) reached 100% clearance of parasitemia 24 h after the last treatment and increased mouse survival to 9 days, a biological profile that render it superior to clinically used sodium artesunate [337] . phenolic mannich bases of chalcone analogues (such as 222, fig. 41 ) have been claimed to possess antimalarial activity against chloroquine-sensitive d10 p. falciparum strain at concentrations ranging from 0.3 to 3 mg/ml [44] . taking into account the structural similarity between phenolic mannich bases 222 and ketonic mannich bases of a,b-unsaturated ketones, a possible mechanism action for compounds 222 could be the inhibition of thioredoxin fig. 41 . antimalarial phenolic mannich bases derived from miscellaneous substrates. reductase in p. falciparum [338] . phenolic mannich bases 223 of 2,4dihydroxybenzaldehyde, its thiosemicarbazone and semicarbazone (fig. 41) , as well as related quinoline-containing derivatives 224 (fig. 41) have been screened against chloroquine-resistant w2 p. falciparum strain [339] . only candidates 223 derived from 1-(7chloroquinolin-4-yl)piperazine had antimalarial activity, while the remaining mannich bases 223 were inactive. all of the candidates 224 were potent antimalarial agents, with mannich base 224 (nr 2 ¼ 4-(7-chloroquinolin-4-yl)piperazin-1-yl) featuring two quinoline motifs in its structure being the most potent (ic 50 ¼ 77 nm) [339] . imines of 4(1h)-pyridones 225 (r 1 and r 2 ¼ h or ch 3 ) (fig. 41) having a phenolic mannich base moiety were active against chloroquine-resistant w2 p. falciparum strain (ic 50 values between 9 and 33 mm) and atovaquone-resistant fcr3 p. falciparum strain (ic 50 values as low as 8 mm), but their potency was lower than that of reference drugs chloroquine or atovaquone [340] . in addition, aminoalkylation of lawsone using various aldehydes and n-alkyl-ferrocenylmethylamines afforded mannich bases 226 (r 1 ¼ alkyl) (fig. 41 ) structurally resembling antimalarial drug atovaquone, but evaluation of three candidates 226 (r 1 ¼ n-c 6 h 13 , n-c 7 h 15 , n-c 8 h 17 ) against p. falciparum showed that they were less potent than atovaquone itself [341] . because of their self-limiting nature, most viral diseases (with the exception of those caused by human immunodeficiency virus, hiv) do not require specific therapy, although treatments are used to bring the condition or its symptoms to an end more quickly. currently available drugs are designed to target four main groups of viruses, namely herpes viruses, hepatitis viruses, influenza viruses, and hiv. recent investigations in the antiviral activity of mannich bases deal mostly with aminomethylated phenols and aminomethylated isatins, although examples of mannich bases with antiviral properties derived from other types of substrates are available in literature. phenolic mannich base arbidol 227 (fig. 42) [342] is a broadspectrum antiviral agent commonly used in russia to treat acute respiratory viral infections, which acts by inhibiting virus-mediated fusion with target membrane and subsequent blockage of virus entry into target cells [343, 344] . using arbidol as lead compound, a group at shenyang pharmaceutical university led by gong initiated a program aiming at investigating structureeanti-hepatitis b relationship for a series of phenolic mannich bases derived from various heterocyclic ring systems. in their first report on this topic, the chinese researchers presented a series of analogues of arbidol 228 (x ¼ so, r 1 ¼ ch 3 , c-c 3 h 5 , r 2 ¼ br) (fig. 42) having various substituents r 2 in the aromatic sulfoxide moiety, and presenting amino residues different than the original dimethylamino group in arbidol (e.g., secondary aliphatic amines, nh-azoles belonging to imidazoles and 1,2,4-triazoles) in the aminomethyl function in position 4 [345] . sar investigation was based on the ability of these compounds to inhibit replication of hepatitis b virus (hbv) and the production of surface antigen of the hepatitis b virus (hbsag) and extracellular form of hepatitis b core antigen (hbeag) in hepg2.2.15 cells infected with hbv, and showed that half of these mannich bases exhibited inhibitory effects on hbv that were superior to reference drug lamivudine. replacement of the original methyl group at n-1 in 228 with cyclopropyl led to an increase in antiviral activity, but enhanced the cytotoxicity of these candidates as well, whereas the presence of fluorine or chlorine as substituents in the aromatic sulfoxide moiety resulted in an improvement of the anti-hbv activity. departure from the original phenylmercapto function in arbidol reduced the cytotoxicity of mannich bases 228 (x ¼ so), leaving in the same time the anti-hbv activity practically unchanged. also, the nature of the amino group in the aminomethyl function appears to have little effect on the anti-hbv activity of the mannich bases reported in this study [345] . the relationship between the presence of a linker (containing two or three atoms between the sulfur atom in the side chain and the phenyl moiety) and the anti-hbv activity of mannich bases 228 (x ¼ soch 2 ch 2 y, y ¼ ch 2 , o or null, r 1 ¼ ch 3 , r 2 ¼ br) was also explored, and candidates having a phenethyl residue proved to be inactive, whereas candidates with a 3-phenylpropyl residue presented remarkable anti-hbv activity [346] . a subsequent study [347] of the anti-hbv activity of arbidol analogues 228 (x ¼ so or so 2 , r 1 ¼ ch 3 , c-c 3 h 5 , r 2 ¼ h) unsubstituted at position 5 of the indole scaffold claimed that the nature of the amino function plays an important role, and that pyrrolidine-and imidazole-containing candidates exhibited better anti-hbv activity than candidates having different amino residues. for another set of mannich bases 228 (x ¼ so or so 2 , r 1 ¼ ch 3 , r 2 ¼ h), the authors suggested that the presence of 4-methylpiperazin-1-yl residue as amino moiety, rather than 1-imidazolyl, 2-methyl-1-imidazolyl or 1-piperidinyl, afforded more potent anti-hvb agents [348] . replacement of the sulfinyl group in the side chain with sulfonyl appeared to enhance the antiviral activity while reducing cellular toxicity of these mannich bases [347] , although the results in the later study [348] supported the opposite conclusion. substitution of the indole scaffold with quinoline in mannich bases 229 (x ¼ s or so) (fig. 42 ) resulted in potent inhibition of hbv dna replication (10-to 66-fold compared to reference drug lamivudine) [349] . analysis of sar for compounds 229 revealed that the presence of 4-fluorophenyl moiety linked to sulfur in the side chain at position 2 of the quinoline scaffolds, in conjunction with amine moieties such as 1pyrrolidinyl, 1-piperidinyl, 1-imidazolyl (but not 4fig. 42 . phenolic mannich bases inspired by arbidol and useful as anti-hepatitis b agents. methylpiperazinyl or morpholinyl) in the aminomethyl function are required for good anti-hbv activity. evaluation of mannich bases 230 (fig. 42 ) derived from a tetracyclic ring system comprising the quinoline scaffold fused with a benzothiopyrane ring system that has various substitution patterns in the aromatic ring identified a significant number of candidates with good inhibition of hbv replication [350, 351] . the search for anti-hbv agents with similar structures continued with the evaluation of a series of phenolic mannich bases 231 (r 1 ¼ ch 3 , c 2 h 5 , ch(ch 3 ) 2 , r 2 ¼ h or f, x ¼ s or so) of 5-hydroxybenzimidazoles substituted at position 2 with 4-alkylmercaptophenyl residues (fig. 42 ) [352] . these compounds exhibited inhibitory effect on the secretion of hbsag that was superior to reference drug lamivudine, but lacked the ability to inhibit the replication of hbv dna in hepg2.2.15 cells at concentrations that were inferior to those corresponding to 50% of their cytotoxicity. the presence of fluorine at position 6 of benzimidazole scaffold and the presence of sulfinyl function appears to be critical for the inhibition of hbsag secretion of mannich bases 231. evaluation of another series of mannich bases 232 (x ¼ s, so, so 2 , r 1 ¼ h, 4-f, 4-och 3 , 4-ch 3 ) of 5-hydroxybenzimidazoles (fig. 42) showed that the thioethers in this series did not inhibit the replication of hbv dna, but the candidates with 4-methylpiperazin-1-yl as amino moiety were good inhibitors of secretion of hbsag, and the inhibitory effect significantly decreased upon oxidation of sulfur in thioethers to sulfinyl and sulfonyl [353] . phenolic mannich bases 233 (r 1 ¼ h, 4-f, 4-cl, 4-br, 4-ch 3 , 3-och 3 ) derived from 6bromo-8-hydroxyimidazo[1,2-a]pyridine-3-carboxylates (fig. 42) , especially those having 4-morpholinyl or 4-methylpiperazin-1-yl moieties in the aminomethyl function, inhibited the replication of hbv dna, but had no inhibitory effect on secretion of hbsag or hbeag [354] . the nature of substituents in the arylmercapto residue modulates the anti-hbv activity, as the decrease of bulkiness of the substituents (from bromine to fluorine, for example) and the presence of lipophilic substituents (e.g., a methyl group) enhance the inhibition of replication of hbv dna, whereas the presence of a 3-methoxy group further increases the activity. phenolic mannich bases 125 derived from chlorokojic acid (fig. 23 ) have been evaluated against herpes simplex virus type-1 (hsv-1) and parainfluenza-3 virus (pi-3). amongst the candidates reported in one study, only two mannich bases had inhibitory concentration in the range of 0.1e0.8 mg/ml against hsv-1, whereas all of the compounds were active in various degrees against pi-3 [152] . all of the mannich bases 125 derived from 1arylpiperazines as amine reagents inhibited both hsv-1 and pi-3, and one candidate 125 (r ¼ 4-(4-methoxyphenyl)piperazin-1-yl) was as potent as reference drug acyclovir against hsv-1 [153] . in addition, candidate 125 (r ¼ 4-(3-chlorophenyl)piperazin-1-yl) presented remarkable activity (0.025e0.4 mg/ml) against pi-3. other aminomethyl derivatives of various phenolic substrates have been tested against different viruses. only one phenolic mannich base 57 (r ¼ nhch 3 ) of norvisnagin (fig. 10) was moderately active against hsv-1 [78] . evaluation of aminomethylated 7-hydroxycoumarin derivatives 234 (fig. 43) against flaviviridae and other viruses led to mixed results [355] . phenolic mannich bases 234 (r 1 ¼ h, r 2 ¼ h or ch 3 ) were generally inactive against bovine viral diarrhea virus (bvdv), yellow fever virus (yfv) or respiratory syncytial virus (rsv), and a few other candidates that were active against bvdv or yfw were also cytotoxic. o-alkylated phenolic mannich bases 234 (r 1 ¼ n-c 3 h 7 , r 2 ¼ h or ch 3 ), and especially candidates having a methyl group at position 4 of the coumarin ring system, were active against bvdv, but they were inactive against yfv or rsv. o-acylated phenolic mannich bases 234 (r 1 ¼ coc 6 h 5 , r 2 ¼ h or ch 3 ) were generally inactive against all three viruses, but one candidate 234 (r 1 ¼ coc 6 h 5 , r 2 ¼ h, nr 2 ¼ 1,2,3,4-tetrahydroisoquinolin-2-yl) had a remarkable activity against rsv, comparable to that of reference drug 6-azauridine, and had also very low toxicity. compounds 234 were not active against a panel of viruses comprising hiv-1, coxsackievirus b2, sb-1 strain of marek's disease virus, vesicular stomatitis virus and a reovirus. in addition, screening of an extensive library of compounds identified mannich bases 235 of 5-chloro-8-hydroxyquinoline (fig. 43) as reactivators of latent hiv-1, which could prove helpful in eradicating the latent reservoir of hiv-1 in resting memory cd4þ t cells, either alone or in combination with other treatments [356] . antiviral activity of mannich bases of isatin and its derivatives is the topic of several investigations. screening of twelve mannich bases 236 derived from semithiocarbazones of 5-nitroisatin (fig. 43 ) against a panel of other viruses afforded no compound with antiviral properties, with the exception of candidate 236 (x ¼ o, r 1 ¼ allyl), which had weak activity against yfv (strain 17d) at subtoxic concentrations. this candidate was more potent than reference drug ribavirin, but was also more cytotoxic [357] . based on results of molecular studies aiming at designing inhibitors of hiv reverse transcriptase, a series of mannich bases 237 (fig. 43 ) have been synthesized [358] . candidates 237 having secondary aliphatic amino moieties in the aminomethyl function showed 92 to 69% inhibition of the enzyme, whereas mannich bases 237 (nr 2 ¼ nhc 6 h 5 ) showed no inhibition. aminomethylation of schiff bases obtained from 5-substituted isatins (r 1 ¼ f, cl, f) and lamivudine using fluoroquinolones (r 2 ¼ ethyl, cyclopropyl; r 3 ¼ h, ch 3 ) as amine reagents gave mannich bases 183 (fig. 32) , which were less potent against hiv than the parent schiff bases, and the most potent candidates 183 (r 1 ¼ f) were also 10-fold less potent than lamivudine itself against hiv [273] . starting from schiff bases of trimethoprim, mannich bases 238 (fig. 43) were obtained using fluoroquinolones as amine reagents. their evaluation against hiv and hepatitis c virus (hcv) showed that mannich bases 238 (r 1 ¼ cl) inhibited replication of hiv in mt-4 cells at effective concentrations (ec 50 ) ranging from 9.4 to 56 mg/ml, and most compounds were active against hcv rna replication (80% inhibition at 50 mg/ml) [162] . mannich base 238 (r 1 ¼ ch 3 , nr 2 ¼ 4-(4chlorophenyl)piperazin-1-yl) and three mannich bases 238 (r 1 ¼ ch 3 ) derived from fluoroquinolones as amine reagents showed inhibition against replication of hiv in mt-4 cells at ec 50 ranging from 11.6 to 28.4 mg/ml [359] . in addition, all of the compounds 238 (r 1 ¼ ch 3 ) were active against hcv rna replication (65% inhibition at 50 mg/ml) [359] . furthermore, a study reports candidate 238 (r 1 ¼ h, nr 2 ¼ 4-(4-nitrophenyl)piperazin-1-yl) as inhibitor of japanese encephalitis virus and west nile virus in vitro, and a remarkable inhibitor of japanese encephalitis virus in a murine model [360] . investigations into the antiviral activity of mannich bases derived from substrates other than phenols or isatins are available in literature as well. the majority of mannich bases 80 (r ¼ cl, och 3 ) (fig. 14) , obtained through n-aminomethylation of thiazolidine-2,4-diones with morpholine, piperidine and variously 1substituted piperazines, showed no activity against severe acute respiratory syndrome (sars) coronavirus [103] . also, all of these mannich bases had antiviral activity against types a and b of influenza virus, but virus inhibition occurred almost at cytotoxic concentration. aminomethylation of the amide function in tetracyclines using fluoroquinolones as amine reagents afforded mannich bases 189 (fig. 34) , and four candidates derived from tetracycline and one derived from minocycline were found to inhibit hiv replication with ec 50 values below 20 mm, while their toxicity against mock infected cem cell line was greater than 140 mm [287] . in addition, all mannich bases 189 showed moderate inhibition of both 3 0 -processing and strand transfer steps of hiv-1 integrase. evaluation of efavirenz mannich bases 191 (fig. 34) led to the discovery of three candidates that were at least as potent as the parent compound against hiv [289] . a large number of indole mannich bases 239 (r ¼ aminomethyl, 3-amino-1-propyn-1-yl) (fig. 43 ) derived from a pentacyclic core, along several acetylenic mannich bases with the same core, have been claimed to be active against hcv and members of the flaviviridae family of viruses [361] . none of the mannich bases 240 (fig. 43) derived from indophenazine as substrate and sulfonamides, anthranilic acid or 2aminopyridine as amine reagents either showed any activity against hiv above their cytotoxic concentrations, but some presented weak activity against hsv, vsv, or vaccinia virus [362] . anticonvulsants are drugs used in the treatment of seizures in epilepsy, a common chronic neurological disorder that affects around 50 million people of all ages worldwide. the discovery of novel antiepileptic drugs relies either on rational design based on the use of well-known pharmacophores (e.g., imides), or on random screening of libraries of compounds. ketonic mannich bases 8 (r 1 ¼ 4-substituted aryloxy, 4substituted arylthio, r 2 ¼ h, nr 2 ¼ n(c 2 h 5 ) 2 ; r 1 ¼ 4fluorophenyloxy, r 2 ¼ h, nr 2 ¼ dimethylamino, 1-piperidinyl, 4morpholinyl, 1-pyrrolidinyl) (fig. 3 ) and the related piperidinols 14 (r 1 ¼ 4-substituted aryloxy, r ¼ c 2 h 5 ) (fig. 4) were examined for anticonvulsant activity in the maximal electroshock (mes) and subcutaneous pentylenetetrazole (scptz) screens [20] . none of the compounds provided protection in the scptz screen, but several candidates 8 and 14 demonstrated anticonvulsant activity in the mes screen below their neurotoxic levels (30 mg/kg). four ketonic mannich bases of type 8 derived from acetophenone or 4hydroxyacetophenone as substrates and common secondary aliphatic amines as amine reagents, as well as the corresponding azines 16 (fig. 4) , were assessed as anticonvulsants using the same two tests. the results showed that anticonvulsant activity of candidates 8 was superior to that of azines 16, and compounds derived from 4-hydroxyacetophenone were active at a dose of 300 mg/kg in the mes test, but no candidate showed anticonvulsant activity in the cptz test [363] . bis-mannich bases 13 (r 1 ¼ h, 4-cl, 4-ch 3 , 2thienyl, r ¼ c 2 h 5 ) and the corresponding piperidinols 14 were protective in the mes test at 30 mg/kg and/or above, while candidate 14 (r 1 ¼ 4-cl, r ¼ c 2 h 5 ) was protective in the scmet test at 300 mg/kg after 4 h [364] . the presence of a 4-chlorophenyl moiety appears to be important for the anticonvulsant activity of these compounds, and analogues having the same moiety were identified as good anticonvulsant agents in a previous study [365] . anticonvulsant activity of phenolic mannich bases of 3hydroxy-4-pyranones has been investigated extensively by aytemir's group. screening of derivatives of allomaltol 174 having a 4substituted piperazin-1-ylmethyl group (fig. 30 ) using mes and scptz tests showed that candidate 174 (r ¼ 3-cf 3 c 6 h 4 ) provided excellent protection against pentylenetetrazole-induced seizures, but was neurotoxic at high dose (300 mg/kg), while candidate 174 (r ¼ 4-clc 6 h 4 ) had high anticonvulsant activity in mes test at all doses after 30 min, without being neurotoxic [305] . evaluation of another series of mannich bases of allomaltol revealed that candidate 174 (r ¼ 2,3-(ch 3 ) 2 c 6 h 3 ) was active in scptz test at 300 mg/kg after 4 h, along with candidate 174 (r ¼ 3-clc 6 h 4 ), which was active in mes test at 300 mg/kg after 5 h [366] . although mannich bases of allomaltol obtained using morpholine or 4-(1-piperidinyl)piperidine as amine reagents had no anticonvulsant activity [366] , a subsequent study dealing with novel mannich bases generated from piperidines as amine reagents reported that candidates 124 (r 1 ¼ 3-ch 3 , r 2 ¼ 5-ch 3 ; r 1 ¼ 4-hoch 2 ch 2 , r 2 ¼ h; r 1 ¼ 4-c 6 h 5 ch 2 , r 2 ¼ h) (fig. 23) were protective in scptz test, while only candidate 124 (r 1 ¼ 4-hoch 2 ch 2 , r 2 ¼ h) provided protection in mes test at 300 mg/kg [367] . use of other piperidines as amine reagent in the mannich reaction with allomaltol as substrate led to candidates 124 (r 1 ¼ 4-(un)substituted phenyl, r 2 ¼ oh, cn, coch 3 ), and two of these mannich bases (r 1 ¼ 4-brc 6 h 4 , r 2 ¼ oh; r 1 ¼ 4-clc 6 h 4 , r 2 ¼ oh) were active in scptz test at 300 mg/kg after 4 h, while all of them were active in mes test either after 0.5 h or after 4 h [368] . in contrast, when allomaltol was replaced with kojic acid as substrate in the mannich reaction, but the same piperidines were used as mine reagents, the resulting candidates 241 (nr 2 ¼ 4,4-disubstituted piperidines) (fig. 44 ) were all active in scptz test either after 0.5 h or after 4 h, but only two of them (r 1 ¼ 4-brc 6 h 4 , r 2 ¼ oh; r 1 ¼ 4-clc 6 h 4 , r 2 ¼ oh) were active in the mes test at 300 mg/kg after 0.5 h, and one candidate 241 (r 1 ¼ c 6 h 5 , r 2 ¼ coch 3 ) was active at any dose after 4 h [368] . mannich bases 241 (nr 2 ¼ 4-substituted piperazines) of kojic acid as substrate and piperazines as amine reagents were generally better anticonvulsants than analogous mannich bases 174 of allomaltol, or than mannich bases 241 derived from kojic acid and 4,4disubstituted piperidines [369] . the authors tentatively explain the enhanced anticonvulsant activity of mannich bases of kojic acid compared to the activity of mannich bases of allomaltol through the possible formation of an extra hydrogen bond in the former compounds. however, mannich bases derived from chlorokojic acid were also good anticonvulsants, and they present, like mannich bases of allomaltol, only one hydrogen bond in their structure [154] . hydantoin represents the core structure of the old generation of antiepileptic drugs, such as phenytoin, and substitution with an aminomethyl moiety was shown to improve activity against mes seizures in mice [370] . evaluation of a library of n-mannich bases 242 (fig. 44 ) derived from 5-cyclopropyl-5-arylhydantoins having 4-substituted piperazines in the aminomethyl function showed that the majority of candidates were effective in the mes or/and scptz screens, and quantitative studies in rats after oral administration showed that three mannich bases 242 (r 1 ¼ h, r 2 ¼ c 6 h 5 , c 6 h 5 ch 2 , 3-ch 3 c 6 h 4 ch 2 ) were more potent than phenytoin in mes test [371] . results from another study [372] showed that candidates 242 were generally more active in mes test than in scptz screen, and chlorine-substituted mannich bases (r 1 ¼ cl) were generally less active than those unsubstituted in the aromatic ring (r 1 ¼ h), whereas candidates derived from 1,2,3,4-tetrahydroisoquinoline as amine reagent in the mannich reaction were less potent than those derived from morpholine or piperazines. compared to candidates 242 obtained from arylpiperazines as amine reagents, mannich bases having alkylene, alkenylene, carbonyl or ester linkers between the piperazine moiety and phenyl ring presented enhanced anticonvulsant protection to pentylenetetrazole-induced seizures, which was noticeable not only after 0.5 h, but after 4 h as well [372] . taking into account the established anticonvulsant properties of many spirohydantoins [373e375], mannich bases 243 (x ¼ nh) of spirohydantoins (fig. 44) have been synthesized and evaluated as anticonvulsants, and while some of them were effective in mes or/ and scptz screens, and were more potent than reference drug phenytoin, their high neurotoxicity precluded further testing [376] . besides hydantoin, succinimide presents the structural requirements for the core structure of good anticonvulsant agents (namely, a nitrogen-containing heteroatomic system with a least one carbonyl group), and the well-established drug ethosuximide is an example for this class of antiepileptic drugs. the group of obniska has been developing novel anticonvulsants for a long time, and mannich bases derived from variously substituted succinimides has been one of the classes of compounds that provided some of the most interesting results reported by these researchers. based on the significant number of candidates that have been synthesized, aminomethylated derivatives 244 of 3phenylsuccinimides (fig. 44) [382] , generally showed protection in mes screen, but some of them were also effective in scptz screen. moreover, a few candidates presented activity not only 0.5 h after administration, but also after 4 or 5 h, which is indicative of quick onset and long duration of anticonvulsant activity. mannich bases 244 of 3-arylsuccinimides derived from other secondary aliphatic amines, such as morpholine, 4benzylpiperidine, 4-cyclohexylpiperazine, were generally effective in both screens [381, 382] . despite the large number of compounds evaluated in these studies, no consistent sars could be established. compounds with good anticonvulsant properties emerged from almost all of these studies, but none of these anticonvulsant mannich bases was deemed sufficiently promising to advance to clinical studies. aminomethylated spirosuccinimides have also been investigated as anticonvulsants. candidates 243 (x ¼ ch 2 ) derived from 4-(3-trifluoromethylphenyl)piperazine and 4-(3chlorophenyl)piperazine as amine reagents in the mannich reaction were the most potent anticonvulsants in this series in mes test, and replacement of substituted aryl with 2-hydroxyethyl rendered the candidates active in both tests [376] . the activity of mannich bases 245 of simpler spirosuccinimides (fig. 44 ) appears to depend [377] and candidates 245 (n ¼ 1 or 2) derived from 4-(2methylphenyl)piperazine [383] were devoid of anticonvulsant activity. on the other hand, mannich bases 245 (n ¼ 1 or 2) obtained from 4-(3-trifluoromethylphenyl)piperazine as amine reagent were efficient in mes screen, but not in scptz screen [383] . evaluation as anticonvulsant agents of mannich bases 246 of succinimides 3,3disubstituted with identical ( (fig. 44) has also been the topic of several recent papers [384e387]. generally, mannich bases obtained from 3,3diphenylsuccinimide were more potent than those obtained from 3-alkyl-3-phenylsuccinimides, which, in turn, were more potent than mannich bases derived from 3,3-dialkylsuccinimides, which were actually inactive in most cases. candidates generated from 4arylpiperazines as amine reagents in the mannich reaction were efficient only in mes test, and the nature and position of the substituent in the aromatic ring attached to piperazine modulate the anticonvulsant activity of these compounds. however, mannich bases 246 derived from 4-(2-hydroxyethyl)piperazine or 4benzylpiperidine were efficient in both screens [384] . the effect of mannich bases 246 with potent anticonvulsant activity on na v 1.2 sodium channel currents was also investigated as a potential mechanism of action for these compounds, and the results showed that the anticonvulsant activity of these candidates correlates nicely with their effectiveness as sodium channel blockers [385, 386] . in addition, there was no direct correlation between anticonvulsant properties and 5-ht 1a , 5-ht 2a , 5-ht 1a and/or 5-ht 7 serotonin receptor affinity [383, 387] . besides hydantoins and succinimides, other substrates featuring the ureido motif in their structure have been aminomethylated with a view to obtain anticonvulsant agents. barbituric acid and its thio analogue have been subjected to the mannich reaction with two amine reagents having a quinazolinone moiety, and the resulting candidates 247 and 248 (x ¼ o or s, r ¼ 6-br, 6-i, 6,8-br 2 ) (fig. 45 ) provided good protection (40e80%, and 50e90%, respectively) in both mes and scptz screens at a dose of 50 mg/kg, while lacking neurotoxicity, or sedative and hypnotic effects [388] . mannich bases 169 of 3-aryl-2-thioxo-2,3-dihydroquinazolin-4(1h)-one (fig. 29 ) showed significant anticonvulsant activity in mes test, as some of these candidates afforded results comparable to those obtain for reference drug phenytoin [240] . several studies concerning the anticonvulsant activity of fused seven-membered ring systems containing two heteroatoms are available in literature. aminomethylated 2,3-dihydro-1,5benzoxazepines 249 (fig. 46) provided protection in the mes test in the range of 30e90% at a dose of 30 mg/kg; candidate 249 (r 1 ¼ 3-och 3 -4-oh, r 2 ¼ 2-och 3 ) was equipotent to reference drugs phenytoin and lamotrigine in mes screen, and was also equipotent to reference drug valproate in scptz screen [389] . another study allowed a direct comparison between the anticonvulsant activities of analogous aminomethylated 2,3-dihydro-1,5-benzoxazepines 250 (x ¼ o) and 2,3-dihydro-1,5benzothiazepines 250 (x ¼ s) (fig. 46) [390] . at a dose of 30 mg/ kg, the latter provided more protection (20e90%) in mes test than the former, with mannich base 250 (x ¼ s, r 1 ¼ 2-cl, r 2 ¼ och 3 ) being the most active compound in this series. ketonic mannich bases 251 (r ¼ h, cl, no 2 ; r 1 er 2 ¼ r 3 er 4 ¼ (ch 2 ) 4 or r 1 ¼ r 2 ¼ r 3 ¼ ch 3 , r 4 ¼ h) having a 2,3-dihydro-1,5benzodiazepine scaffold as the amino moiety (fig. 46) were evaluated using a model in which the seizures were induced chemically, and some of these compounds provided protection after 0.5 h, whereas only candidates 251 derived from acetophenone (r ¼ h) provided protection up to 2 h [391] . inflammation is part of the complex, nonspecific immune response of vascular tissue that occurs in reaction to any type of injury, such as pathogens, irritants, damaged cells, etc. the initial response of the body to harmful stimuli is initiated by cells already present in all tissues, and is achieved by the increased movement of plasma and leukocytes (especially granulocytes) from blood into the injured tissue, where they release a series of cell-derived mediators, triggering afterwards a cascade of biochemical events that propagate the inflammatory response. nonsteroidal antiinflammatory drugs (nsaids) are commonly used for treatment of inflammation, along with its symptoms (fever, pain, swelling), but they present significant side effects after long-term usage, such as gastrointestinal lesions, kidney injury, and cardiovascular risk. along with many other classes of compounds, mannich bases of various structures have been investigated as part of the ongoing search for novel anti-inflammatory drugs. ketonic mannich bases 252 (r 1 ¼ h, ch 3 , so 2 ch 3 ) derived from 2arylidenecyclohexanones and aromatic amines (fig. 47) have been evaluated using xylene-induced ear swelling test and carrageenan-induced paw edema, and candidate 252 (r ¼ h) was superior to reference drug ibuprofen in both tests, whereas several candidates 252 (r ¼ ch 3 ) were less efficient, but still more effective than ibuprofen, in the same tests [392] . administration of ketonic mannich base 253 (fig. 47 ) to rats with a chronic inflammatory process induced by insertion of cotton pellets led to increased phagocytic capacity of peripheric neutrophils, enhanced activity of the serum complement system, and higher catalase activity, while a slightly decrease in the activity of superoxide dismutase was observed [393] . a few double mannich bases 105 of 4,6dimethoxybenzofuran-3(2h)-one (fig. 21) inhibited the production of pro-inflammatory cytokines tnf-a and il-6 by 76e100% at a concentration of 10 mm, but they were more cytotoxic than reference drug dexamethasone, which had comparable effects with candidates 105 on the production of the same cytokines at only 1 mm [134] . investigation of the anti-inflammatory activity of mannich bases 254 (r ¼ h, f, cl, br, or 2 ; r 2 ¼ och 3 and oc 4 h 9 -n) having amino acids isoleucine and methionine as amine moieties (fig. 47 ) was performed using both carrageenan-induced paw edema model and pellet-induced granuloma model, and resulted in the discovery of two anti-inflammatory agents 254 (r ¼ och 3 and oc 4 h 9 -n; r 1 ¼ ch 2 ch 2 sch 3 ) derived from methionine [394] . at a dose of 25 mg/kg, these two mannich bases 254 had 81% and 71%, respectively, of the efficiency of the reference drug diclofenac (dose of 10 mg/kg) on the reduction of paw swelling. at the same dose, these two candidates 254 also showed 88% and 79%, respectively, of the activity of reference drug indomethacin (dose of 3 mg/kg) on chronic inflammation. a continuation of this study was undertaken with a view to broaden the nature of amino acids (cysteine, threonine, methionine, isoleucine, asparagine, and glutamine) as amine moieties in mannich bases 254, and also the nature of the alkoxy substituents in the aromatic ring, but these novel candidates had no anti-inflammatory activity at 5 mg/kg, with the exception of two candidates 254 (r ¼ oc 2 h 5 ; r 1 ¼ ch 2 sh, ch 2 conh 2 ), which displayed mild activity in the acute inflammation model [395] . only one example of mannich bases obtained from simple phenols as potential anti-inflammatory agents is available in recent literature. thus, evaluation of four phenolic mannich bases 255 (fig. 48) using formalin-induced acute inflammation model in mice revealed that one candidate had reliable activity upon parenteral administration (50 mg/kg), whereas reference drug diclofenac sodium exhibited only two-thirds of its activity, albeit at 8 mg/kg [396] . phenolic mannich bases 256 of resveratrol analogues containing a pyridinyl moiety and either one, two or three aminomethyl residues (fig. 48) were tested using xylene-induced ear edema in mice at 200 mg/kg, and two of them had 80% of the efficiency of reference drug ibuprofen, whereas the remaining candidates were less potent [397] . the anti-inflammatory activity of mannich bases of polyhydroxylic phenols was also investigated. at a dose of 10 mg/kg, two candidates 113 (nr 1 r 2 ¼ 1-piperidinyl and 4-morpholinyl) derived from 4,6-diacetylresorcinol (fig. 22 ) had a slightly lower activity than that of reference drug indomethacin in carrageenan-induced paw edema [398] . three candidates 257 (r 1 ¼ 3-cl, nr 2 ¼ 4-methylpiperazin-1-yl; r 1 ¼ 2-br, nr 2 ¼ 1piperidinyl or 1-pyrrolidinyl) (fig. 48) were more efficient at inhibiting the production of tnf-a at a concentration of 10 mm than reference drug dexamethasone at 1 mm [399] ; under the same experimental conditions, most mannich bases in the study were also more efficient at inhibiting the production of il-6 than dexamethasone. the same researchers also investigated the action on enzymes that are involved in inflammation (such as cyclooxygenases (cox), trypsin and b-glucuronidase) of phenolic mannich bases 258 (r 1 ¼ 2-f, 2-cl, 2-br, 3-f, 3-cl, 3-br) of chalcone analogues (fig. 48) having the same substitution pattern in ring a as candidates 257 [400] . with one exception, none of the candidates inhibited the activity of trypsin, whereas most mannich bases in this study inhibited the activity of b-glucuronidase. candidates 258 derived from chalcone analogues having a halogen at position 3 of the b ring were generally more potent than those derived from chalcone analogues having a halogen at position 2 of the b ring. in addition, a few mannich bases 258 were poor inhibitors of cox-1, but excellent inhibitors of cox-2, and the majority of the candidates were more efficient at inhibiting cox-2 than reference drug aspirin. in a different study [401] , two out of four phenolic mannich bases of other chalcone analogues were found to reduce rat paw edema induced by carrageenan, and although these compounds were found to be good inhibitors of trypsin this time, no satisfactory correlation with their antioxidant, free radical scavenging, or lipooxygenase inhibition could be established. because inducible nitric oxide synthase (inos) generates high levels of nitric oxide that modulates inflammations through multiple pathways, the inhibition of this enzyme by phenolic mannich bases of heterocyclic analogues of chalcones with various structures was also investigated. this type of phenolic mannich bases was found to strongly inhibit no production, with ic 50 values ranging between 10.5 and 0.018 mm [402] . benzoxazines 117 (fig. 22) , easily obtained from 4hydroxyacetophenones through a double mannich reaction, inhibited the swelling of rat paw in various degrees when administered orally in doses equimolar to 20 mg/kg of indomethacin [145] ; compared to indomethacin, one candidate 117 (r ¼ 4-f) was more efficient, while another candidate 117 (r ¼ 4-och 3 ) was equipotent. chalcone analogues 259 (r ¼ 4-och 3 or 4-ch 3 ) derived from these benzoxazines (fig. 48) had a more pronounced antiinflammatory activity compared to candidates 117, and all of them displayed 70e90% of the efficiency of reference drug indomethacin [403] . phenolic mannich bases of naturally-occurring benzopyranones have also been tested as anti-inflammatory agents. most mannich bases 260 derived from 7hydroxycoumarin (fig. 48) were superior to reference drug indomethacin at reducing rat paw edema induced by carrageenan, and two candidates 260 (nr 2 ¼ 4-morpholinyl, 1-piperazinyl) were 1.6 times more efficient than indomethacin at 10 mm without significant inhibition of cox-1 [404] . irisolidone is an isoflavone which was isolated from pueraria spp., and was found to exert its antiinflammatory action through suppression of inos gene expression and pro-inflammatory cytokines in activated microglia [405] . chemical modification of irisolidone by means of the mannich reaction using primary aliphatic and aromatic amines as amine reagents led to candidates 261 ( fig. 48) with enhanced ability to inhibit nitric oxide production compared to parent irisolidone [406] . anti-inflammatory activity of mannich bases of 2,3-dihydro-1,2,4-triazole-3-thiones has also been investigated. several candidates 133f (table 1) have been evaluated using carrageenaninduced rat paw edema model, and the activity of one of them (133f, r 2 ¼ 2-ch 3 c 6 h 4 , nr 2 ¼ 4-morpholinyl) was comparable to that of reference drug ibuprofen [171] . mannich bases 133i with secondary aliphatic amino moieties (dimethylamino, diethylamino, 1-pyrrolidinyl) in the aminomethyl function were as efficient as reference drug celecoxib in reducing rat paw edema both after 1 h and after 2 h, and they also had lower ic 50 values (around 1 nm) for the inhibition of cox-2 compared to celecoxib (1.9 nm) [407] . as far as 5-substituted 2-aminomethyl-4-arylideneamino-2h-2,3dihydro-1,2,4-triazole-3-thiones 134 (table 1) are concerned, the majority of mannich bases 134c had, upon administration of either 20 mg/kg or 40 mg/kg, a lower anti-inflammatory activity in carrageenan-induced rat paw edema model than reference drug indomethacin (5 mg/kg), although one candidate (134c, r 2 ¼ 2,6-cl 2 c 6 h 3 , nr 2 ¼ 4-phenylpiperazin-1-yl) inhibited edema formation at the higher dose almost as efficiently as indomethacin [182] . starting from ibuprofen, two separate studies reported the synthesis and anti-inflammatory activity of mannich bases 262 having different arylideneamino moieties at position 4 of the 2,3-dihydro-1,2,4-triazole-3-thione scaffold (fig. 49) . the most potent compounds in this series were those having either a 4-morpholinyl or a 4-methylpiperazin-1-yl residue in the aminomethyl function. when common 4-substituted benzaldehydes (r 2 ¼ 4-clc 6 h 4 , 4-ch 3 c 6 h 4 , 4-brc 6 h 4 , 4-no 2 c 6 h 4 ) were used to generate the azomethine moiety, several candidates 262 had anti-inflammatory activity comparable with that of reference drug diclofenac, and were generally more efficient than ibuprofen at every time interval up to 3 h [408] . also, the most potent compounds in this series were those having either a 4-morpholinyl or a 4-methylpiperazin-1-yl residue in the aminomethyl function. on the other hand, when 3aryl-4-formylsydnones were used to generate the azomethine moiety, the resulting mannich bases 262 were consistently more potent than the analogues in the previously mentioned series of compounds, but all of these candidates were less efficient than reference drug indomethacin in reducing rat paw edema [409] . several mannich bases 134h showed a peak in their antiinflammatory activity at 1 h post-injection (from 50% to 130% edema inhibition compared to indomethacin), whereas the antiinflammatory activity of other candidates 134h peaked at 4 h post-injection (from 84% to 100% edema inhibition compared to indomethacin) [186] . all of the mannich bases 263 (fig. 49 ) had only moderate anti-inflammatory activity, with the most potent compound in the series showing approximately 80% of the efficiency of reference drug indomethacin [410] . a few mannich bases 264 and other structurally related aminomethylated 2,3-dihydro-1,2,4-triazole-3-thiones (fig. 49 ) reduced significantly the inflammatory response (maximum inhibition between 30 and 59%) compared to reference drug diclofenac (inhibition between 42 and 63%), and some of them presented fast onset of their antiinflammatory action, while others had a long-lasting anti-inflammatory effect [411] . the anti-inflammatory activity of mannich bases of 2,3-dihydro-1,3,4-oxadiazole-2-thiones has been scarcely examined. several mannich bases 139a (table 2) , especially those derived from ibuprofen as starting material for the 1,3,4-oxadiazole-2-thione substrate and generated from 4-arylpiperazines as amine reagents in the aminomethylation step, were as efficient as reference drug diclofenac at reducing rat paw edema [193] . also, mannich base 265 (fig. 49 ) had anti-inflammatory activity comparable to that of reference drug indomethacin in carrageenan-induced rat paw edema test [412] . several papers published by g€ okhan's group have reported the anti-inflammatory activity of mannich bases of 2benzoxazolinones. one of their studies showed that candidates 266 (r 1 ¼ ch 3 , r 2 ¼ 2-or 4-clc 6 h 4 co) having an acyl moiety at position 6 of the benzoxazolidinone scaffold were more potent than their analogues 266 (r 1 ¼ 2-or 4-clc 6 h 4 co, r 2 ¼ h) with the same acyl group at position 5 (fig. 49 ); in addition, the antiinflammatory activity of two of these candidates was equipotent to that of reference drug indomethacin [413] . substitution with fluorine in the phenyl ring of the acyl moiety appears to be less favorable for the anti-inflammatory activity of candidates 266 (r 1 ¼ h, r 2 ¼ difluorobenzoyl) [414] . mannich bases 266 (r 1 ¼ ch 3 , r 2 ¼ h) having 4-arylpiperazine residues in the aminomethyl function were all less potent than reference drug indomethacin in carrageenan-induced rat paw edema test, but the results suggest that the nature of the substituent in the aryl group of piperazines plays an important role in the anti-inflammatory activity of these compounds [415] . a few mannich bases 266 (r 1 ¼ no 2 , r 2 ¼ h) had an anti-inflammatory effect comparable to that of reference drug indomethacin 3 h after administration, but their efficiency in reducing the swelling reached a plateau afterwards, whereas that of indomethacin continued to increase in time [416] . two studies have reported the anti-inflammatory activity of mannich bases of isatins. aminomethylation of derivatives of 5methylisatin thiosemicarbazone afforded mannich bases 267 (r 1 ¼ r 2 ¼ h or ch 3 , nr 2 ¼ secondary aliphatic amines) (fig. 50) , which showed moderate anti-inflammatory activity (18e44% inhibition of edema at a dose of 100 mg/kg) compared to reference drug diclofenac (65% inhibition of edema at a dose of 45 mg/kg) [417] . several mannich bases 268 (fig. 50) , which were obtained from a derivative of isatin hydrazone, had anti-inflammatory activity comparable to that of reference drug diclofenac, and the highest level of activity was observed after 2 h [418] . a correlation in this series between anti-inflammatory activity and the nature of the amino moiety in the aminomethyl function was noticed, as the activity decreased with the increasing lipophilicity of the amino group. a series of n-mannich bases 269 of benzimidazole derivatives (fig. 50) were evaluated as anti-inflammatory agents using formalin-induced paw edema method. compared with reference drug diclofenac (50 mg/kg), they all caused significant reduction of paw edema, albeit at different doses (200 mg/kg for mannich base 269 (r 1 ¼ h or ch 3 ) and 40 mg/kg for mannich bases 269 of 2styrylbenzimidazole) [419] . also, several mannich bases 269 (r 1 ¼ c 2 h 5 ), derived from both secondary aliphatic amines and primary arylamines, showed moderate anti-inflammatory activity 4 h after administration (33e57% of the activity of reference drug aspirin at the same dose of 100 mg/kg) [420] . mannich bases obtained from substrates other than those mentioned so far have been examined as anti-inflammatory agents as well. thus, n-mannich bases 270 (nr 2 ¼ 1-pyrrolidinyl, 1piperidinyl, 4-morpholinyl) of pyrimido[1,6-a]azepine derivatives (fig. 51 ) had moderate activity (46e58% reduction of edema compared to that recorded for reference drug diclofenac) [421] , whereas n-mannich bases 271 of a tricyclic system derived from pyrimido[1,6-a]azepine (fig. 51) were less potent (anti-inflammatory activity of approximately 40% of that of diclofenac) [422] . two aminomethylated pyridazinones bearing a thiophene ring, namely compounds 272 and 273 (fig. 51) , showed 65% and 95% reduction of rat paw edema, respectively, compared to reference drug indomethacin [423] . even when administered in a higher doses relative to that of reference drug, none of the mannich bases 274 (r ¼ h, ch 3 , och 3 , cl, x ¼ o or ch 2 ) derived from isoxazolines (fig. 51) was as efficient as indomethacin in reducing rat paw edema [424] . out of the two acetylenic mannich bases 275 (x ¼ o or ch 2 ) with a betulonic acid scaffold (fig. 51 ) that were investigated as antiinflammatory agents, only the piperidine derivative was almost as efficient as reference drug indomethacin in reducing rat paw edema; the morpholine analogue had only half of the activity of the piperidine mannich base [425] . as pain is a symptom of inflammation, the anti-inflammatory and analgesic activities of novel candidates are usually evaluated at the same time. therefore, it is not surprising that many of the studies that report the anti-inflammatory activity of mannich bases also offer information on their analgesic potential. several ketonic mannich bases 252 (r 1 ¼ h, ch 3 , so 2 ch 3 ) derived from 2-arylidenecyclohexanones and aromatic amines (fig. 47) were equipotent to reference drug ibuprofen in both acetic acid-induced writhing test and hot plate test [392] . one of the most potent candidate was compound 252 (r ¼ r 1 ¼ h) derived from ptoluidine, but a few mannich bases derived from 2-(4methylsulfonylbenzylidene)cyclohexanone were also efficient as pain relievers. phenolic mannich bases of 1-and 2-naphthols substituted in either rings of naphthalene system with various functions, which were synthesized using preformed aminomethylation reagents (e.g., imonium salts obtained from aromatic aldehydes and secondary aliphatic amines), were claimed to have analgesic activity [426] . the claim is difficult to assess, because only two candidates have been evaluated, and no comparison with established analgesics was provided. in addition, while candidate 276 (x ¼ ch 2 ) (fig. 52 ) was efficient (92% inhibition of the writhing reaction), the second candidate 276 (x ¼ o) offered only modest protection against pain (30% inhibition of the writhing reaction). mannich bases of 2,3-dihydro-1,2,4-triazole-3-thiones with analgesic activity have been reported in several studies. candidates 133f (r 2 ¼ 2-ch 3 c 6 h 4 , nr 2 ¼ 4-morpholinyl; r 2 ¼ 4-ch 3 oc 6 h 4 , nr 2 ¼ 4-methylpiperazinyl) ( table 1) , which had good antiinflammatory activity, were also tested for analgesic activity; their efficiency, determined using tail flick method in albino rats, was comparable to that of reference drug ibuprofen [171] . several mannich bases 262 (fig. 49) showed analgesic activity (tail flick latency between 6.8 and 7.1 s) that was comparable with that of reference drug pentazocine (tail flick latency of 7.45 s), while the rest of the compounds were moderately active [409] . mannich bases 263 (fig. 49) were less efficient in the tail flick test, as the reaction time for the most potent compound in the series was approximately 80% of the latency provided by reference drug pentazocine [410] . two candidates 139a (table 2) , both derived from ibuprofen as starting material for the 2,3-dihydro-1,3,4oxadiazole-2-thione substrate and generated using either ethyl piperidine-4-carboxylate or 4-(4-fluorophenyl)piperazine as amine reagents in the aminomethylation step, were more efficient analgesics than reference drug diclofenac in hot plate test [193] , while mannich base 265 (fig. 49 ) was equipotent to reference drug diclofenac in acetic acid-induced writhing test [412] . analgesic activity of mannich bases of 2-benzoxazolinones was also determined for the same candidates that were investigated for anti-inflammatory activity. in the library of mannich bases 266 derived from 2-benzoxazolinones (fig. 49 ) carrying a benzoyl moiety in the aromatic ring (r 1 or r 2 ¼ substituted benzoyl), no significant difference in analgesic activity between the 5benzoylated and the 6-benzoylated analogues could be observed [413] . although most candidates provided moderate to low protection in either tests used to determine their analgesic activity (namely acetic acid-induced writhing test and p-benzoquinoneinduced abdominal constriction test), two mannich bases derived from 6-(substituted benzoyl)-2-benzoxazolinones were found to be as efficient as reference drug aspirin. thus, analgesic activity of mannich base 266 (r 1 ¼ h, r 2 ¼ 2,6-f 2 c 6 h 3 co, nr 2 ¼ 4-(4acetylphenyl)piperazin-1-yl) was equipotent to that of aspirin [414] , while analgesic activity of mannich base 266 (r 1 ¼ ch 3 , r 2 ¼ 4-clc 6 h 3 co, nr 2 ¼ 4-(4-fluorophenyl)piperazin-1-yl) was slightly poorer than that of aspirin [413] . in the series of mannich bases 266 derived from 5-methyl-2-benzoxazolinone, several compounds showed better analgesic activity compared to reference drug aspirin, and the analgesic activity for all the compounds was consistently higher than their anti-inflammatory activity, suggesting that these mannich bases might exert their analgesic activity centrally [415] . two mannich bases 266 derived from 5-nitro-2benzoxazolinone were also found to possess analgesic activity comparable to that of aspirin [416] . mannich bases 267 of derivatives of 5-methylisatin thiosemicarbazone (fig. 50) were moderately efficient (16e53% protection) in preventing acetic acid-induced writhing in mice at a dose of 100 mg/kg, while reference drug diclofenac provided 74% protection in the same test at a dose of only 45 mg/kg [417] . mannich bases 268 of isatin hydrazone (fig. 50) carrying a quinazoline moiety and derived from acyclic secondary aliphatic amines (dimethylamine, diethylamine) were the most potent; their analgesic effect was superior or comparable to that of reference drug diclofenac 2 h after administration, but it decreased rapidly afterwards [418] . n-mannich bases 269 (fig. 50 ) obtained from benzimidazole using dimethylamine or diethylamine as amine reagents were found to be moderate analgesics at a dose of 200 mg/kg relative to paracetamol (100 mg/kg), while mannich base 269 derived from 2methylbenzimidazole as substrate and diphenylamine as amine reagent was a poor analgesic candidate [419] . owing to their toxicity, mannich bases derived from 2-styrylbenzimidazole were administered at a lower dose (20 and 40 mg/kg), and their analgesic activity ranged from moderate (nr 2 ¼ 4-morpholinyl) to very good (nr 2 ¼ diethylamino or 1-piperidinyl) when compared to paracetamol [419] . n-mannich bases 269 of 2-ethylbenzimidazole had analgesic activity comparable to that of reference drug pentazocine only when administered in doses that were 25 times greater than that of pentazocine [420] . other mannich bases 269 derived from 2-substituted benzimidazoles (r 1 ¼ ch 2 nhnhc 6 h 5 or 2-hoc 6 h 4 ) also showed moderate to good analgesic activity in acetic-acidinduced writhing test (62e84% of the analgesic activity of diclofenac at the same dose) [427] . evaluation of a first series of n-mannich bases 277 derived from 2h-4,6-dimethyl-3-oxo-2,3-dihydroisothiazolo[5,4-b]pyridine ( fig. 52 ) led to identification of weak to moderate analgesic agents [428] . amongst them, candidates derived from 4-aryl-or 4benzylpiperidine and those having a 4-(2-substituted phenyl) piperazine as the amine moiety were the most efficient analgesics in writhing and hot plate tests. a second series of mannich bases 277 was subsequently synthesized, and some of the candidates displayed significant activity in the writhing test, with analgesic activity 2 to 10 times more potent than that of aspirin and 1.5 to 10 times weaker than that of morphine, used as reference drugs in the study [429] . excess of reactive oxygen species produced in living organisms can cause oxidative stress and damage cells by initiating chain reactions that lead to lipid peroxidation, dna damage or protein oxidation. besides the complex system of antioxidant metabolites and enzymes that naturally prevent cell damage, exogenous antioxidants may sometimes be required to keep reactive oxygen species at an optimum level. use of the mannich reaction to generate novel chemical entities capable of acting as antioxidants is presented in this section. ketonic mannich bases 109 and 110 (fig. 21) , which were obtained from arylamines as amine reagents and 3-acetylcoumarine and 2-acetylbenzofuran as substrates, respectively, were tested for antioxidant activity by evaluating their ability to scavenge 1,1diphenyl-picrylhydrazyl (dpph) radical [138] . the most efficient candidates in each series, namely 109 (r ¼ h) and 110 (r ¼ n(ch 3 ) 2 ), showed moderate potency in scavenging dpph radical (approximately 65%) compared to standard butylated hydroxytoluene (90%). substitution of the aromatic ring with electron-withdrawing groups appears to reduce the antioxidant ability of these mannich bases. a large number of phenolic mannich bases have been reported in the literature as potential antioxidants. antioxidant activity of two phenolic mannich bases 278 derived from thymol (fig. 53) has been assessed by means of xanthine oxidase inhibition test for the cell-free system, and by inhibition of lipid peroxidation using ratliver homogenate [430] . both candidates, and especially mannich base 278 having morpholine as amine moiety, presented enhanced antioxidant activity in both tests compared to parent thymol. three phenolic mannich bases 114 (nr 1 r 2 ¼ 4-ch 3 oc 6 h 4 nh, 1piperidinyl and 4-morpholinyl) derived from 4,6diacetylresorcinol (fig. 22) , designed primarily as antiinflammatory agents, were also evaluated for their ability to inhibit lipid peroxidation; results showed that these candidates were more efficient than indomethacin at preventing lipid peroxidation, and that the antioxidant activity may be correlated with their ulcerogenic activity [398] . only three mannich bases 257 (fig. 48) , all of them having piperidine as the amine moiety (nr 2 ¼ 1-piperidinyl), showed moderate to high ability in scavenging dpph radical (49e74% of dpph scavenging ability of standard gallic acid), while the rest of the candidates were either poor scavengers of dpph radical, or failed to react with dpph radical at all [399] . although all of the phenolic mannich bases 197 showed efficiency as antioxidants in various degrees, candidates 197 (nr 2 ¼ diphenylamino, 4-morpholinyl, 1-piperazinyl) (fig. 36) were the most potent scavengers of hydrogen peroxide, their activity being comparable to that of standard ascorbic acid, but inferior to that of standard butylated hydroxyanisole [302] . selected tacrinee8-hydroxyquinoline hybrids 279 (fig. 53) , that were developed primarily as agents for the treatment of alzheimer's disease, exhibited also potent peroxyl radical absorbance capacities (2.6e4.7 trolox equivalents/mmol of mannich base), as determined by means of orac-fl method (oxygen radical absorbance capacity by fluorescence) [431] . phenolic mannich bases of natural flavanones have been designed and synthesized with the view to improve antioxidant efficiency, bioavailability and water solubility of parent flavanones. only three mannich bases 41 (r ¼ oh, r 1 ¼ h, r 2 ¼ 1-pyrrolidinyl, diethylamino or diisopropylamino) of apigenin (fig. 7) exhibited antioxidant activity greater than that of apigenin, while the rest of candidates 41 presented antioxidant activity comparable to that of apigenin [58] . antioxidant activity of these apigenin derivatives was concentration-dependent, and dpph radical scavenging ability of the most potent mannich bases 41 was almost the same as that of the standard ascorbic acid at a concentration of 1.25 mg/ml. scutellarein was also aminomethylated to give mannich bases 41 (r ¼ r 1 ¼ oh, r 2 ¼ aminomethyl), which had the ability to scavenge 50% of dpph radical in the sample at concentrations ranging from 24 to 33 mm, but no comparison with a well-established antioxidant was provided in the study [432] . mono-and bis-mannich bases 280 fig. 53 ) were synthesized and evaluated as inhibitors of photooxidation of a2e (a pigment of the lipofuscin of retinal pigment cells, thought to play a role in macular degeneration) [433] . these candidates showed sufficient antioxidant ability to inhibit noncellular and intracellular photooxidation of a2e, and were superior as antioxidants to quercetin itself. on the other hand, phenolic mannich bases obtained from other known antioxidants such as sesamol or 1-(2-hydroxy-4-methoxyphenyl)-3phenylprop-2-en-1-one were ineffective inhibitors of a2e photooxidation at 200 mm [433] . phenolic mannich bases of chalcone analogues such as candidates 258 (r 1 ¼ 2-f, 2-cl, 2-br, 3-f, 3-cl, 3-br) (fig. 48) were modest to poor scavengers of dpph radical (3e58% reduction of dpph absorption) compared to standard quercetin (86% reduction of dpph absorption) [400] . results for dpph scavenging ability of phenolic mannich bases derived from other chalcone analogues obtained in a different study are also in line with the antioxidant data recorded for mannich bases 258, as the greatest reduction of dpph absorption was only 13% at concentrations as high as 1 mm of mannich base [401] . however, one candidate in this series scavenged superoxide radical efficiently, while another candidate was a potent inhibitor of heme dependent lipid peroxidation [401] . several mannich bases 133g derived from 5-(2-thienyl)-2,3dihydro-1,2,4-triazol-3-thiones (table 1) were as efficient antioxidants as standard ascorbic acid (over 90% reduction of dpph radical), and showed enhanced antioxidant activity over the parent 2,3-dihydro-1,2,4-triazole-3-thiones [172] . a series of mannich bases 139 [1, 4] dioxin-6-yl, nr 2 ¼ substituted primary arylamines) ( table 2) were designed as antioxidant agents, and were evaluated using scavenging dpph radical assay, scavenging 2,2 0 -azino-bis(3-ethylbenzothiazoline-6sulfonic acid) radical cation (abts) assay, and ferric reducing antioxidant power assay [434] . more than half of these mannich bases showed greater dpph radical scavenging ability than butylated hydroxytoluene (ic 50 ¼ 44 mm), and seven of them exhibited greater antioxidant activity than trolox (ic 50 ¼ 30 mm) in the same assay. a few candidates 139 with high dpph scavenging activity, along with other mannich bases 139, were also very good scavengers of abts radical cation (their activity was greater than that of trolox). in ferric reducing antioxidant power assay, three mannich bases 139 showed better activity than trolox, and other seven were more potent than butylated hydroxytoluene. mannich bases 139 nr 2 ¼ 3,4,5-f 3 c 6 h 3 ) were the only compounds to exhibit high potency in all three assays, and they were also more efficient than trolox in inhibiting lipid peroxidation in mice liver microsomes homogenate [434] . n-mannich bases 149 of succinimide (r 1 ¼ h or phenyl, nr 2 ¼ nhc 6 h 5 , 2-pyridinyl) (fig. 27) and an n-mannich base of phthalimide showed moderate dpph scavenging activity compared to standards vitamin c and vitamin e, while their ability to inhibit peroxidation of linoleic acid was moderate to weak [215] . also, several n-mannich bases 166 of saccharin (fig. 29) were antioxidants as potent as standard ascorbic acid in the abts assay, and more potent antioxidants than saccharin itself [237] . n-mannich base 281 derived from a 3,5-disubstituted pyrazoline (fig. 53) had dpph scavenging and nitric oxide scavenging activities comparable to standard antioxidants ascorbic acid and rutin; the presence of the phenolic hydroxyl group could be responsible for the antioxidant activity of this compound [435] . finally, antioxidant activity of two c-mannich bases 282 of uracil (fig. 53) was determined by means of measuring the rate of oxidation of 2-propanol [436] ; addition of compounds 282 to the reaction mixture reduces the rate of oxidation to levels comparable to the rate of oxidation in the presence of butylated hydroxytoluene. a small number of studies deal with the investigation of mannich bases as antihypertensive agents. phenolic mannich bases appear to be particularly remarkable as blood pressure-lowering substances. several single and double mannich bases of various phenols and having thiomorpholine as amine moiety showed a gradual effect on systolic, diastolic and mean arterial pressure, starting at a dose 0.1 mg/kg; in the case of reference drugs captopril, losartan and omapatrilat, the same effect was noticeable at 0.001 mg/kg [437] . in a manner similar to the aforementioned reference drugs, these phenolic mannich bases also induced a gradual (but significant) reduction of heart rate in anesthetized mice. double mannich base 283 (fig. 54 ) emerged as a valuable candidate, with one of the lowest effective dosage in this collection, while exhibiting the highest antihypertensive activity in conscious spontaneous hypertensive rat model [437] . the same researchers examined the antihypertensive effect of double mannich base 284 with a 1,4-dihydropyridine moiety in its structure (fig. 54) , but the results showed that the activity of this candidate was inferior to that of double mannich base 283, presumably due to the change in bulkiness of the substituent para to the phenolic hydroxyl [438] . the presence of two aminomethyl functions in the structure of 284 may have been essential in preserving the antihypertensive activity of this candidate to a reasonable level, while replacement of thiomorpholine in 283 with morpholine in 284 could be also the cause for the poorer antihypertensive properties of candidate 284 relative to those of mannich base 283. in an attempt to synthesize aminomethylated 4-(naphthyloxy) butanoic acids (e.g., compound 285, were obtained when 4-(naphthalen-1-yloxy)butanoic acid was subjected to aminomethylation [439] . at a concentration of 5 mg/ kg, candidate 285 (nr 2 ¼ 1-piperidinyl) lowered blood pressure in anesthetized cats similarly to propranolol, while compound 286 (nr 2 ¼ 4-phenylpiperazin-1-yl) was superior to propanolol at the same dose (fall of blood pressure of 60 mm hg, duration of the effect of 120 min). it is also worth mentioning that the antihypertensive effect of a c-mannich base of 2-naphthol, namely 1fig. 54 . mannich bases as agents for blood pressure regulation. pyrrolidinylmethyl-2-naphthol 287 (fig. 54) , was reported in an earlier publication [440] . a large collection of mannich bases 288 (r 1 ¼ h, ch 3 , c 2 h 5 , ch 2 ch(ch 3 ) 2 , c 6 h 5 , och 3 , cl) (fig. 54) was evaluated for antihypertensive activity by the non-invasive tail cuff method, and several candidates were found to significantly reduce mean arterial blood pressure, albeit at higher doses than reference drug hydralazine [441] . the presence of alkyl groups as substituent r 1 seems to be favorable for the antihypertensive activity, whereas the nature of the amine moiety does not appear to influence the activity. several mannich bases 289 (r 1 ¼ ch 3 , c 2 h 5 , n-c 4 h 9 , ch 2 c 6 h 5 ; r 2 ¼ ch 3 , c 6 h 5 ) of imidazo[1,2-a]benzimidazoles (fig. 54 ) were found to reduce arterial blood pressure in anesthetized rats with 20% at doses that were lower than the dose at which reference drug dibazole produces the same effect (22 mg/kg) [442] . analogous aminomethylated imidazo[1,2-a]benzimidazoles 290 (r 1 ¼ ch 3 , n-c 4 h 9 , ch 2 c 6 h 5 ) (fig. 54 ) were more efficient antihypertensive agents than mannich bases 289, as they reduce arterial blood pressure with 20% at doses lower than those recorded for candidates 289. several octahydroquinazoline derivatives 291 (r ¼ h, 2-f, 4-f, 4-cl, 4-br, 4-ch 3 , 4-oh) (fig. 54 ) were obtained through a double mannich reaction starting from 3-(4-chlorophenylamino)-5,5dimethyl-2-cyclohexenone and arylamines, and were shown to produce insignificant changes in both arterial blood pressure and heart rate at a dose of 5 mg/kg [443] . however, derivatives 291 (r ¼ och 2 conhn]chc 6 h 4 r 1 , r 1 ¼ h, 4-ch 3 , 4-no 2 ) of a candidate in the initial series afforded significant decreases in both systolic and diastolic arterial blood pressure, with rapid onset of action (5 min) and minor decrease of heart rate in anesthetized male adult albino rats [443] . on the other hand, candidate 291 (r ¼ 4-cl) produced a time-dependent significant increase in both systolic and diastolic arterial blood pressure, without causing tachycardia for 30 min, which makes this compound useful for treatment of hypotension. a small number of studies report the activity of mannich bases against parasites other than plasmodium spp. among these parasites, which are the cause of parasitic infections especially in developing countries, different species from the trypanosomatidae family are pathogenic to humans and cause african trypanosomiasis (sleeping sickness, trypanosoma brucei), american trypanosomiasis (chagas' disease, trypanosoma cruzi) or leishmaniasis (leishmania spp.). in addition, one study investigated the activity of mannich bases against entamoeba histolytica, and one study reported the anti-schistosoma activity of mannich bases derived from praziquantel. all parasitic protozoa belonging to trypanosoma spp. have a unique thiol metabolism based on the flavoenzyme trypanothione reductase. this enzyme could be therefore considered a promising target for rational drug design against african sleeping sickness, chagas' disease, and different forms of leishmaniasis, owing to its absence of in the mammalian host, the structural differences to related host enzymes, and its essential role for parasite survival. because unsaturated ketonic mannich bases react readily with thiols, and because several such compounds were shown to be efficient mechanism-based inhibitors of p. falciparum thioredoxin reductase [338] , a study concerning the ability of these compounds to interact with both trypanothione reductase and free trypanothione was undertaken [444] . candidates 292 (nr 2 ¼ dimethylamino, 1-piperidinyl, 4-morpholinyl) (fig. 55 ) inactivated trypanothione reductase, but only in the presence of nadph, suggesting that reduction of this enzyme prior to its interaction with the mannich base is essential. the divinyl ketone arising from the deamination of candidates 292 is the actual inhibitor, and its activity against trypanothione reductase was higher than that of parent mannich bases; unfortunately, this divinyl ketone was also too reactive to be considered a drug candidate. mannich bases 292 displayed only modest activity against all strains of intracellular parasites, which may be explained by reaction with glutathione present in millimolar concentrations in the cytosol of the mammalian host cells. nonetheless, they showed a significant effect against extracellular t. b. rhodesiense, which might (at least partially) be due to their high reactivity toward trypanothione reductase and trypanothione. with trypanothione reductase validated as a drug target in trypanosomiasis, design and synthesis of novel unsaturated mannich bases based on melaminophenyl arsenical drug melarsoprol was subsequently pursued [445] . candidates 293 (r 1 ¼ cl, h, ch 3 ) (fig. 55) were efficient in vitro trypanothione reductase inhibitors, and while they did not display any significant activity in cell-based assays against t. cruzi, they were active towards t. brucei. the presence of the melamine residue para to the enone motif did not result in any improvement in the trypanocidal potency of 293 (r 1 ¼ cl) compared to hit compounds 292. however, the presence of the melamine residue meta to the enone motif significantly lowered the ic 50 against the human cell line used in the study, which is indicative of these compounds' high cytotoxicity. on the other hand, phenolic mannich base 294 (fig. 55) was basically inactive towards all parasites. mannich bases 293 were taken up effectively into cells despite the absence of p2 and hapt1 carriers, which suggests that the main route of entry for these compounds was not through aminopurine transporters. stemming from the observation that heterocyclic pyrazolopyridine ring system can be considered analogous to quinoline, and because aminoquinoline derivatives are efficient antimalarials, several derivatives featuring the pyrazolopyridine scaffold were designed and tested against leishmania amazonensis, in the evolutive form of promastigotes [446] . thus, both mannich bases 295 (r 1 ¼ c 6 h 5 , r 2 ¼ ch 3 , c 6 h 5 ) (fig. 55 ) are active antileishmanial agents with ic 50 values of 390 and 120 nm, whereas aminoquinoline derivative amodiaquine had ic 50 ¼ 890 nm. from the structureeactivity point of view, the results suggest that pyrazolopyridine ring system is a bioisostere of quinoline, and that the presence of the carbethoxy group in the structure of candidates 295 does not influence significantly the biological activity. amebiasis is a contagious disease of the human gastrointestinal tract that is caused by parasitic protozoa e. histolytica. all the candidates in a small library of piperazine mannich bases 139d of 5-(4pyridinyl)-2,3-dihydro-1,3,4-oxadiazole-2-thione ( table 2) were active against hm1:imss strain of e. histolytica, but only three of them were more potent than reference drug metronidazole (ic 50 ¼ 1.81 mm) [447] . the amine residues in the aminomethyl function of these active mannich bases were 4-ethylpiperazin-1-yl (ic 50 ¼ 327 nm), 4-(4-fluorophenyl)piperazin-1-yl (ic 50 ¼ 245 nm), and 4-(2-methoxyphenyl)piperazin-1-yl (ic 50 ¼ 1.06 mm). in addition, cytotoxicity of these antiamoebic candidates was low (in the concentration range of 2.5e250 mm). out of four newly synthesized mannich bases 296 of praziquantel (fig. 55) , two candidates (nr 2 ¼ n(c 3 h 7 -n) 2 and nhch 2 ch 2 oh) exhibited significant in vitro anti-schistosoma activity (100% worm killing at 40 mm and 30 mm, respectively), but they were not as efficient as praziquantel itself (100% worm killing at 10 mm) [448] . platelets are crucial for hemostasis, as they connect to one another through receptor bridges, form aggregates, and finally plug the tear in the interrupted endothelium. however, the aggregation of platelets leading to formation of clots can also be triggered by irregularities on the vessel wall, resulting in abnormal clot formation, which is the primary factor in the development of thrombotic disorders such as unstable angina, myocardial infarction, stroke and peripheral vascular diseases, especially when it occurs in the coronary artery. platelet aggregation is also initiated by endogenous substances, such as collagen, thrombin, prostaglandin endoperoxides, thromboxanes, arachidonic acid, adenosine diphosphate (adp), etc. inhibition of platelet aggregation represents a promising strategy for the treatment of thrombotic diseases, and several studies have reported the activity of mannich bases as inhibitors of platelet aggregation. several types of phenolic mannich bases represented by structures 24e32 (fig. 6) were also evaluated as inhibitors of platelet aggregation induced by adp or collagen at concentrations of 20 mm or 10 mg/ml, respectively [449] . numerous candidates having various structures showed good inhibitory effects and were more potent than reference drug clopidogrel, whereas nine compounds in this collection exhibited inhibitory activity in the range of 90e100% in both models. good platelet aggregation inhibitory activity was associated with the presence of a pyridyl moiety as ring b in the structure of chalcone analogues, and also by the presence in ring a of a hydroxy group meta to the carbonyl function. phenolic mannich bases 41 (r ¼ r 1 ¼ oh, r 2 ¼ aminomethyl) of scutellarein (fig. 7) were investigated as thrombin inhibitors, and their influence on several parameters such as prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen was determined [432] . all of these candidates showed greater thrombin inhibitory activity compared to parent scutellarein. mannich base derived from scutellarein and containing a morpholinyl residue in the aminomethyl function was the most potent of all, and was subsequently selected for molecular docking experiments with thrombin. these experiments revealed that the morpholinylmethyl group occupies deep pocket s3 of the thrombin binding site, whereas the scutellarein part of the inhibitor's molecule is anchored by three hydrogen bonds within the active site. the effect of mannich bases 289 (r 1 ¼ ch 3 , c 2 h 5 , n-c 4 h 9 , ch 2 c 6 h 5 ; r 2 ¼ ch 3 , c 6 h 5 ) and 290 (r 1 ¼ ch 3 , n-c 4 h 9 , ch 2 c 6 h 5 ; (fig. 54 ) on adp-induced aggregation of rabbit thrombocytes was studied in vitro [442] . several candidates 289 and most candidates 290 were found to have lower effective concentrations (ec 50 ) at which they decrease the degree of aggregation by half than reference drug acetylsalicylic acid. cellular effects of thrombin, including platelet aggregation, are mediated through the activation of thrombin receptor par-1 belonging to the family of four g-protein-coupled receptors called protease-activated receptors. par-1 has become an attractive drug discovery target, and peptide-mimetics or small organic molecules with par-1 antagonist properties have already been designed and synthesized. an indole mannich base motif has been incorporated in the structure of a series of novel peptide-mimetics 297 (r ¼ 4-ch 3 oc 6 h 4 ch 2 , 3,4-f 2 c 6 h 3 ch 2 , naphthalen-1-ylmethyl, naphthalen-2-ylmethyl) ( fig. 56 ) capable to bind to par-1 [450] . the ability of these candidates to inhibit par-1-induced platelet aggregation has been tested by measuring the degree of aggregation of human platelets, and also by establishing the degree of inhibition of contraction of aortic rings. compounds 297 (r ¼ 4-ch 3 oc 6 h 4 ch 2 , 3,4-f 2 c 6 h 3 ch 2 ) belonging to the series of 6-aminoindole derivatives were the most potent candidates, with values of inhibitory concentration that were about 5 times lower than reference compound rwj54003 for 75% inhibition of platelet aggregation. in addition, these results were confirmed by the enhanced inhibitory activity of these two candidates on the contraction of aorta rings when compared to the activity of rwj54003, an effect that became more evident with the increase of par-1 dose. candidates in the series of 5-aminoindole derivatives were found inactive or weak inhibitors in both assays. anti-ulcer agents are a class of drugs used to treat ulcers in the stomach and the upper part of the small intestine. acid peptic disease is a chronic pathology that affects millions of people worldwide, and it has been estimated that 10% of the world population will develop this condition in their lifetime [451] . an imbalance between aggressive factors (such as gastric acid, helicobacter pylori infection, excessive intake of anti-inflammatory drugs, immoderate consumption of alcohol, high concentrations of reactive oxygen species) on one hand, and protective factors (e.g., mucus, bicarbonate anion, prostaglandins, good blood flow, efficient cellular repair, endogenous and exogenous antioxidants) on the other hand is considered to be the cause of ulcers. treatment of ulcers and their symptoms relies on pain relievers, antiacids and cytoprotective agents to allow the healing of ulcers, and agents to prevent the recurrence of ulcers, such as proton pump inhibitors, muscarinic antagonist pirenzepine or h2 receptor antagonist cimetidine. the ability of mannich bases to act as anti-ulcer agents has been reported in a small number of studies. anti-ulcer activity of saminomethyl derivatives 170 generated from 4,6-diaryl-2mercaptopyrimidines (fig. 29 ) as substrates and secondary aliphatic amines as amine reagents in the mannich reaction was evaluated in vivo using aspirin-induced ulcer model in albino rats [241] . based on the ulcer score, the mean ulcer index and the degree of protection were calculated and compared to those of reference drug omeprazole. five candidates 170 (r 1 ¼ 4-clc 6 h 4 , r 1 ¼ 3-no 2 c 6 h 4 or 4-ch 3 oc 6 h 4 ) offered more than 50% protection, while other five mannich bases 170 (r 1 ¼ 4-clc 6 h 4 , r 1 ¼ 4-clc 6 h 4 , 3-no 2 c 6 h 4 or 4-(h 3 c) 2 nc 6 h 4 ) had only moderate anti-ulcer activity (approximately 30% protection) compared to omeprazole (99% protection). aminomethylation of 1,4-dihydropyrimidines with sulfanilamide as amine reagent afforded mannich bases 298 (fig. 57) , whose ability to reduce the volume of acid secretion was determined by pyloric ligation method [452] . three candidates 298 (r ¼ 4-ch 3 oc 6 h 4 , 3-ch 3 o-4-hoc 6 h 3 , 2-furyl) presented good antiulcer activity (ulcer indices in the range of 0.18e0.35 at a dose of 10 mg/kg), while reference drug omeprazole had an ulcer index of 0.08 at a dose of 1 mg/kg. a small number of furo [3,2-g] flavones of type 299 (r 1 ¼ c 6 h 5 , 4-clc 6 h 4 , 3-pyridinyl; r 2 ¼ h or ch 3 ) and 300 (r 1 ¼ c 6 h 5 , 3-pyridinyl) (fig. 57) , aminomethylated either at position 6 or 9, have been evaluated as gastroprotective agents using the ethanol-induced gastric ulcer model in rats [453] . the mean values of the protection index for these mannich bases were in the range of 20e44%, and no comparison with an anti-ulcer reference drug was provided in the study. the best three candidates 299 (r 1 ¼ 3-pyridinyl, r 2 ¼ ch 3 , nr 2 ¼ 4-methylpiperazin-1-yl), 300 (r 1 ¼ 3-pyridinyl, r 2 ¼ och 3 , nr 2 ¼ 4-methylpiperazin-1-yl) and 300 (r 1 ¼ c 6 h 5 , r 2 ¼ h, nr 2 ¼ 4-morpholinyl) have a methoxy group at position 4 as a common structural feature; the corresponding mannich bases having a hydroxyl group instead of methoxy were significantly less active. mental disorders comprise a broad range of problems, with different symptoms, generally characterized by some combination of abnormal thoughts, emotions, behavior and relationships with others. common neurological conditions labeled as mental disorders include depression and anxiety, while schizophrenia and bipolar disorder stand out as mental disorders that are severe and disabling. untreated mental, neurological and substance use disorders exact a high toll, accounting for 13% of the total global burden of disease, while unipolar depressive disorder is the third leading cause of disease burden, accounting for 4.3% of the global burden of disease. current predictions indicate that depression will be the leading cause of disease burden globally by 2030 [454] . a range of different types of treatment for mental disorders are available, and the most suitable treatment depends both on the disorder and on the individual. a major option for many mental disorders is psychotherapy, while another option is psychiatric medication. amongst several groups of drugs that are currently employed in psychiatric medication, antidepressants treat clinical depression as well as anxiety and a range of other disorders, anxiolytics (including sedatives) are used for anxiety disorders and related problems such as insomnia, mood stabilizers are used primarily in bipolar disorder, and antipsychotics are used for psychotic disorders, notably for positive symptoms in schizophrenia. selective serotonin reuptake inhibitors (ssris) play an important role in pharmacotherapeutic treatment of depression. in an attempt to modify the general ssri structural motif of g-phenoxypropylamine, two ketonic mannich bases 301 (r ¼ cl, br) (fig. 58 ) derived from 4-chloro-and 4-bromoacetophenone as substrates and 4-benzylpiperidine as amine reagent were synthesized, the carbonyl function in these amino ketones was subsequently reduced, and the resulting secondary hydroxyl was then converted into an ether group through reaction with 1-chloro-4trifluoromethylbenzene [455] . although the designed ssri analogues targeted in this study showed no antidepressant activity, the intermediate ketone mannich bases 301 were as effective as reference drugs fluoxetine, sertraline or imipramine at similar dosage in a validated experimental model of depression in mice such as the forced swimming test. an innovative computer-assisted approach based on the prediction of activity spectra for substances (pass) has been applied for the discovery of new anxiolytics [456] . an initial database comprising 5494 structures was generated by virtual combinatorial design of highly diverse chemical compounds, including different types of heterocycles such as thiazoles, pyrazoles, isatins, fused imidazoles, with the view to increase the probability of finding new chemical entities as anxiolytics. out of the eight hits obtained from this database, four candidates were mannich bases. ketonic mannich base 302, mannich base 303 derived from an imidazo[2,1-b] benzo[d]thiazole and two mannich bases 304 (r 1 ¼ f, r 2 ¼ ch 3 ; r 1 ¼ no 2 , r 2 ¼ c 6 h 5 ) derived from imidazo[1,2-a]pyridines (fig. 58 ) were synthesized and tested as potential anxiolytics using the conflict situation test. all of the candidates showed an anxiolytic effect that was comparable or greater than that of reference drug medazepam. mannich base 304 (r 1 ¼ no 2 , r 2 ¼ c 6 h 5 ) was the most potent anxiolytic in this study, being two times more potent than medazepam. a collection of compounds sharing a benzoxepin scaffold as common structural feature was evaluated for their sedativeehypnotic effect using phenobarbital-induced sleep test [457] . among these compounds, three ketonic mannich bases 305 (nr 2 ¼ 1-piperidinyl, 4-methylpiperazin-1-yl, 4-morpholinyl) (fig. 58 ) decreased the onset of phenobarbital-induced sleep and prolonged the duration of hypnosis when administered in a dose equimolar to that of reference drug phenobarbital. the hypnotic activity of candidates 305 (nr 2 ¼ 1-piperidinyl, 4-methylpiperazin-1-yl) was comparable to that of phenobarbital, while mannich base 305 (nr 2 ¼ dimethylamino) exhibited only moderate activity, and mannich base 305 (nr 2 ¼ 4-(2-chlorophenyl)piperazin-1-yl) was virtually inactive. therefore, the nature of the amino residue in these mannich bases seems to have a significant impact on their hypnotic activity. in addition to biological activities of mannich bases presented so far, isolated studies were found to report various other biological activities for mannich bases. these singular results are covered in this section, without any attempt to arrange them in a systematic order. two phenolic mannich bases derived from 2,4-and 2,6-di-tbutylphenol as substrates and dimethylamine as amine reagent were evaluated as hepatoprotective agents against experimental toxic hepatitis induced by tetrachloromethane. the degree of liver damage was evaluated in terms of alanine aminotransferase activity in blood serum and malonic dialdehyde content in liver homogenates. even at a dose of 10% of the corresponding ld 50 , the ability of these two candidates to diminish the hepatotoxic action of tetrachloromethane was superior to that of reference compound emoxypine [458] . in addition, in an assay using the same tetrachloromethane-induced hepatitis model, two acetylenic mannich bases 275 (x ¼ o or ch 2 ) with a betulonic acid scaffold (fig. 51 ) were shown to decrease alkaline phosphatase activity and lower alanine aminotransferase and aspartate aminotransferase activities in blood serum compared to control [425] . acetylenic mannich base 306 (fig. 59 ) was tested on guinea pig spontaneously beating atria with a view to evaluate its negative chronotropic activity, but the potency of this candidate was approximately four times lower than that of bradycardic agent zatebradine, and was therefore excluded from subsequent testing as blocker of hyperpolarization-activated current [459] . ondansetron analogues 307 (r 1 ¼ ch 3 ) having a piperazine moiety instead of imidazole (fig. 59) were synthesized and evaluated as anti-emetic agents using a retching model [460] . all the candidates were effective to some extent when administered at a dose of 8 mg/kg, but only mannich base 307 (r ¼ 2-pyrimidinyl) had anti-emetic activity comparable to that of reference drug ondansetron at low dosage (2 mg/kg). several 7-aminomethylated b-thujaplicin analogues 308 ( fig. 59) were tested against oxidative stress-induced death of ht22 cells following exposure to glutamate [461] . piperazine-containing mannich bases 308 were more potent than parent b-thujaplicin in protecting glutamate-challenged ht22 cells, with ec 50 values ranging from 0.08 to 1.7 mm. because the most potent candidates were those having a chroman moiety as substituent at n4 in the piperazine residue, the high in vitro neuroprotective activity of these mannich bases may be due to the potent antioxidant effect imparted by the chroman moiety. analogous morpholine mannich base 308 was also active in protecting ht22 cells from oxytosis, but it was less active than the piperazine-containing b-thujaplicin derivatives. the presence of the isopropyl group also seems to be important for the neuroprotective activity of these compounds, since an analogous mannich base derived from tropolone was not active. estrogen deficiency after menopause is one of the most common causes of osteoporosis. hormone replacement therapy is widely used to prevent bone loss, although it presents potential drawbacks such as increased risk of uterine bleeding and/or hyperplasia, increased risk of endometrial, breast or ovarian cancer, higher occurrence of myocardial infarction, cardiovascular disease, etc. conjugate 309 of 17b-estradiol and iminodiacetic acid (fig. 59 ) was designed as an estrogen-containing, bone-seeking agent that could prevent bone loss with lesser side effects, and was subsequently synthesized by means of the mannich reaction [462] . mannich base 309 showed significant affinity for bone, but lower affinity for ovary and uterus than 17b-estradiol, while it maintained 92% of the affinity of 17b-estradiol for osteoblast estrogen receptors. candidate 309 did not induce uterine hypertrophy, and lower levels of biochemical markers of bone turnover (e.g., osteocalcin, alkaline phosphatase, c-terminal telopeptide fragment of type i collagen cterminus) were found in the group of rats treated with 309 than in ovariectomized rats, which suggests decreased bone turnover. administration of candidate 309 improved bone mineral density and trabecular architecture after ovariectomy, but did not suppress body weight increase. these results suggest that compound 309 is effective in preventing ovariectomy-induced bone loss while exhibiting exhibited fewer adverse side effects than 17b-estradiol, making mannich base 309 a better choice for the prevention of postmenopausal osteoporosis. three bis-p-mannich bases 310 (r 1 ¼ r 2 ¼ ch 3 ; r 1 er 2 ¼ (ch 2 ) 3 ; r 1 er 2 ¼ (ch 2 ) 4 ) (fig. 59) , derived from diethyl phosphite as substrate and amino acids as amine reagents in the mannich reaction, have been used to investigate the induction of adipogenic or osteogenic differentiation of mesenchymal stem cells isolated from human adipose tissue (hmads cells) [463] . candidates 310 did not affect the adipocyte differentiation, but induced the inhibition of osteoblast formation without any detectable cytotoxic effect, whereas reference drug sodium alendronate elicited a cytotoxic effect even at the lowest concentration used in the study (10 à7 m). therapeutic efficacy and toxicity profiles of ketonic double mannich base 311 (fig. 59) , a putative immunosuppressant which preferentially inhibited jak3 as opposed to several other kinases, were examined [464] . candidate 311 blocked il-2-induced activation of jak3 and its downstream substrates stat5a/b, while it failed to inhibit several other enzymes, including growth factor receptor tyrosine kinases, src family members, and serine/threonine protein kinases. mannich base 311 alone prolonged kidney allograft survival and induced transplantation tolerance, and its combination with cyclosporin a presented therapeutic synergism. candidate 311 showed no nephrotoxicity, did not affect hematopoiesis or lipid metabolism, and was not metabolized by the cytochrome p450 3a4 isoform. therefore, because mannich base 311 prolongs allograft survival without several toxic effects associated with current immunosuppressive drugs, it may provide significant clinical benefits for transplant patients. an important number of studies report the activity of mannich bases as enzyme inhibitors. although the studies covered in this section usually validate the importance of the topic through a rational and evidence-supported connection between the enzyme under scrutiny and a certain medical condition, they only examine the action of mannich bases as enzyme inhibitors, and do not provide any experimental evidence that these mannich bases could be actually useful agents for the treatment of specific medical conditions. starting from tacrine, the first drug approved for the treatment of alzheimer's disease and a potent inhibitor of both acetylcholinesterase (ache) and butyrylcholinesterase (buche), multifunctional compounds 279 (fig. 53 ) that combine neuroprotective, antioxidant, metal-binding properties, and dual inhibition of ache and buche in a single small molecule have been designed and synthesized through the mannich reaction [431] . tacrinee8hydroxyquinoline hybrids 279 were potent inhibitors of both ache and buche of bovine origin with ic 50 ranging from submicromolar to nanomolar concentrations. candidates containing an unsubstituted 8-hydroxyquinoline moiety and a methylene tether of 7e10 carbon atoms had the most potent inhibitory activities. selected mannich bases 279 were evaluated as inhibitors of human cholinesterases, and they exhibited ic 50 values in the range of 0.5e5.5 nm against ache, and in the range of 6.5e55 nm against buche. mannich base 279 (r 1 ¼ r 2 ¼ h, n ¼ 7) was the most potent dual inhibitor of human ache and buche in this library [431] . other mannich base hybrids 312 (fig. 60) were designed as dual binding site inhibitors of ache by combining tacrine (a recognized inhibitor of catalytic binding site of ache) with the indanone moiety of donepezil (known to be responsible for the binding of this drug to the peripheral site of ache) [465] . their evaluation as inhibitors of ache (bovine erythrocyte) and buche (human serum) using ellman's method showed that the activity of two of these candidates was modest, while the third candidate 312 (z ¼ h, r ¼ och 3 , x ¼ (ch 2 ) 3 ) exhibited moderate activity against ache (25 nm) and good activity against buche (0.6 nm). apparently, the difference in activity between these candidates is due to the lengthening by one methylene group of the alkyl chain linking the tacrine and indanone moieties. 2-benzoxazolone mono-mannich bases 313 (fig. 60 ) derived from secondary aliphatic amines or primary arylamines, and bis-mannich bases 314 derived either from primary aliphatic amines (x ¼ nr, r ¼ c 2 h 5 , r 1 c 6 h 4 ch 2 ch 2 , r 1 ¼ h, 4-cl, 3,4-(ch 3 o) 2 ) or piperazine have been evaluated for ache inhibitory activity using ellman's method. the degree of inhibition was in the range of 70e82% at a concentration of 1 mm, but decreased to 8e34% at 0.1 mm, whereas the degree of ache inhibition by tacrine was virtually the same at both concentrations (greater than 99%) [466] . the most potent inhibitor in this series at both concentration was bis-mannich base 314 derived from piperazine. inhibitory activity against ache and buche of phenolic mannich bases 58 (r 1 ¼ h, ch 3 , allyl, prenyl; nr 2 ¼ n(ch 3 ) 2 , n(c 2 h 5 ) 2 , 1pyrrolidinyl, 1-piperidinyl, 4-morpholinyl) of xanthone derivatives ( fig. 10 ) was found to be moderate to good compared to that of reference drug galantamine [467] . candidates 58 derived from diethylamine as amine reagent in the mannich reaction were generally the most potent inhibitors of both enzymes. the nature of alkyl moiety r 1 modulates the selectivity of inhibitors 58 towards one of these enzymes; thus, the most potent inhibitors of ache feature a methyl group as r 1 , whereas the increasing bulkiness of this substituent appears to favor the inhibition of buche. mannich base 58 (r 1 ¼ prenyl, nr 2 ¼ n(c 2 h 5 ) 2 ) was the most potent dual inhibitor in this series, and molecular docking studies were performed with the view to garner information on the binding mode of this inhibitor with both enzymes. several phenolic mannich bases 315 of naturally occurring flavanone oroxylin a (fig. 61) were more potent inhibitors of intestinal a-glucosidase than parent oroxylin a, but the same candidates were less potent than oroxylin a against yeast a-glucosidase [468] . nonetheless, the most potent inhibitor of intestinal aglucosidase in this series was still 5.5 less potent than reference drug acarbose. because all of the candidates 315 which failed to inhibit both enzymes were derived from acyclic secondary amines as amine reagents in the mannich reaction, the alicyclic nature of secondary amines may responsible for the good inhibitory activity against a-glucosidases in this series. ketonic mannich bases 316 derived from nabumetone (fig. 61) possess modest inhibitory activity against intestinal a-glucosidase (approximately 20 mm), in addition to modest inhibitory activity against another therapeutic target for type 2 diabetes mellitus, obesity and related states of insulin resistance, namely proteintyrosine phosphatase 1b [469] . however, two mannich bases 316 (r ¼ h or 4-oh) were good agonists of peroxisome proliferatoractivated receptors, which are major regulators of lipid and glucose metabolism. a novel series of inhibitors was designed by retaining the nabumetone moiety, while sulfanilamide and 3amino-5-methylisoxazole served as amine reagents in the synthesis of ketonic mannich bases of type 317 and 318, respectively (fig. 61 ) [470] . candidates 317 were generally more potent inhibitors of a-glucosidase than analogous 318, suggesting that sulfonamide moiety is a more potent pharmacophore than aminoisoxazole. mannich base 317 (r ¼ 4-br) inhibited 80% of a-glucosidase activity at a dose of 10 mg/ml. replacement of the sulfonamide moiety with 4-aminobenzoic acid, with a view to mimic the acidic, hydrophilic part of molecules with known antidiabetic activity, led to a novel series of mannich bases 319 (r 1 ¼ h). a second series of candidates 319 (r 1 ¼ c 2 h 5 ) (fig. 61) was also evaluated as a-glucosidase inhibitors, but their activity was generally poorer than that of mannich bases 319 (r 1 ¼ h) derived from 4-aminobenzoic acid [471] . for example, the most potent a-glucosidase inhibitor (67% inhibition) in the series derived from 4-aminobenzoic acid was candidate 319 purine nucleoside phosphorylase (pnp) catalyzes the phosphorolytic cleavage of inosine, guanosine and their 2 0 -deoxy analogues to (deoxy)ribose 1-phosphate and hypoxanthine or guanine. genetical deficiency in pnp leads to complete t-cell deficiency early in life and eventual death of infants from virus infections, and pnp has been identified as a target for the treatment of t-cell lymphoma, rheumatoid arthritis, psoriasis, multiple sclerosis, and other t-cell mediated disorders. a transition state analogue is a compound that occupies the catalytic site of an enzyme and induces the slow conformational changes that would normally occur to place the catalytic site in the appropriate geometry for the search that would locate the transition state with the normal substrate of the enzyme. schramm et al. have developed a series of mannich bases of 9-deazahypoxanthine as transition state analogues for purine nucleoside phosphorylase inhibition, generally called immucilins. although aminomethylated purines and analogues have been present within the firstand second-generation of pnp inhibitors [472, 473] , they have been obtained through reductive amination, and not through direct mannich reaction. because a more expeditious synthesis of second-generation pnp inhibitors by means of the mannich reaction has been later developed [474] , the third generation of these inhibitors included several examples of mannich bases 320 (fig. 62 ) obtained through direct aminomethylation of substrate 9-deazahypoxanthine with amino alcohols such as ethanolamine, 3-amino-propan-1-ol, 4-amino-butan-1-ol, diethanolamine and 3-(2-hydroxyethylamino)propan-1-ol as amine reagents [475] . unfortunately, all these candidates obtained through direct aminomethylation proved to be modest or poor inhibitors of pnp (dissociation constants k i in the range of 780 to 120,000 pm) compared to other mannich bases previously investigated, such as 321 (dadme-immucilinh, k i ¼ 8.5 pm) or 322 fig. 61 . mannich bases as inhibitors of a-glucosidase. (dadme-immuciling, k i ¼ 7.0 pm) (fig. 62) . nonetheless, this study identified two acyclic, simplified alternatives of immucilin analogues, namely 323 (k i ¼ 9.0 pm) having an open-chain amino alcohol with two asymmetric carbon atoms, and 324 (k i ¼ 5.0 pm) derived from achiral dihydroxyaminoalcohol seramide (fig. 62) , as potent inhibitors of pnp. because the enantiomers of both immu-cilinh and dadme-immucilinh 321 have been shown to have pnp binding properties that differ considerably [476] , and since access to enantiomerically pure starting azasugar employed for the generation of 322 requires a suitable enzyme-based route, the discovery of the two simpler mannich bases 323 and 324 represents a significant step forward in the development of clinically useful pnp inhibitors. sulfur-containing transition state analogues have been developed as well, originally as specific inhibitor of pnp from p. falciparum, but it was later shown that sulfur-containing candidates analogous to dadme-immucilinh 320 or mannich base 323 also bind to human native pnp [477] . although human pnp tolerates substitution of 5 0 -hydroxyl in transition state analogues 321 and 324 with alkylthio and arylthio groups, the slow-onset nature of inhibition is lost, and inhibitor dissociation constants increase by two to three orders of magnitude. fluorine-containing analogue 325 (fig. 62) of dadme-immucilinh 321 has also been evaluated as human pnp inhibitor, and its enantiomers exhibit slow-onset binding constants of 32 pm for [(3s,4s)-325] and 1.82 nm for [(3r,4r)-325] [478] . in addition, direct mannich reaction has been used to generate in a similar fashion potent transition state inhibitors for other enzymes, such as methylthioadenosine phosphorylase methylthioadenosine nucleosidase [479, 480] or purine specific nucleoside hydrolase [481] . a large library of a-, band g-amino ketones was screened with a view to discover inhibitors of transglutaminase, but only b-amino ketones (ketonic mannich bases) strongly inhibited this enzyme [482] . mannich bases derived from aliphatic ketones as substrates, or those derived from alkyl aryl ketones as substrates and primary amines as amine reagents were weak inhibitors (ic 50 > 30 mm) of transglutaminase. potent transglutaminase inhibitory activity resided with ketonic mannich bases derived from alkyl aryl ketones as substrates and secondary aliphatic amines as amine reagents. both the nature of the aryl moiety in the substrate and the nature of the alkyl groups attached to the nitrogen atom influenced transglutaminase inhibitory activity of these candidates. generally, heteroaryl-substituted substrates (2-thienyl, 2-benzothienyl, 2furyl, 3-furyl, pyridinyls, pyrazinyl) fared better than substrates having aryl moieties (phenyl, naphthyls), and t-butyl, isopropyl, benzyl or 2-hydroxyethyl groups (but not phenyl) as alkyl substituent at nitrogen afforded potent transglutaminase inhibitors, such as candidate 326 (ic 50 ¼ 81 nm) (fig. 63) . because disulfides are well-known transglutaminase inhibitors, a novel series of b-amino ketones 327 (r ¼ h, n ¼ 0; r ¼ cooch 3 , n ¼ 0; r ¼ cooch 3 , n ¼ 1) (fig. 63 ) derived from cystamine, dimethyl cystine ester, and dimethyl homocystine ester as amine reagents in the mannich reaction were synthesized and found to be approximately 300 times more active than the starting disulfides [483] . mannich bases derived from 2-acetylthiophenes were once more the most potent inhibitors in this series, while the nature of the disulfide-containing amine moiety did not significantly influence the activity of candidates 327 having the same heterocyclic or carbocyclic moiety r 1 . mannich bases 328 derived from 3,4-dimethylphenol ( fig. 63 ) have been evaluated in vitro as inhibitors of two human carbonic anhydrase (hca, ec 4.2.1.1) isozymes i and ii using the hydratase and esterase assays, respectively [484] . only two candidates exhibit weak hca ii inhibitory effects on esterase activity, whereas other two mannich bases 328 could be used as carbonic anhydrase activators. phenolic mannich bases 280 derived from quercetin (fig. 53 ), 329 derived from baicalein and 330 derived from 1-(2-hydroxy-4methoxyphenyl)-3-phenylprop-2-en-1-one ( fig. 63 ) were screened for inhibition of cyclin-dependent kinases using a biochemical assay method based on fluorescence resonance energy transfer [485] . candidates 280 and 330 are essentially devoid of inhibitory activity of cyclin-dependent kinases; on the other hand, baicalein mannich bases 329 were 6e20 times more potent than the parent flavone, suggesting that the presence of a nitrogen atom at c-8 is crucial for the inhibition of cyclin-dependent kinases, while the presence of a second heteroatom in the amine moiety (e.g., oxygen in morpholine, sulfur in thiomorpholine, nitrogen in n-methylpiperazine) further increases the potency of these candidates. virtual screening of a commercial library containing drugs and drug-like molecules against a 3d model of heparanase led to the identification of several candidates with high scores for binding affinity; they were subsequently tested in nmr competitive inhibition experiments using suramine as a known heparanase inhibitor [486] . one of these candidates is amodiaquine 201 (fig. 38) , and a subset of fourteen representative compounds that retained the characteristic 4-phenylamino-chloroquinoline scaffold of amodiaquine, but presented different functional groups in the phenylamino moiety, was further selected for nmr competitive inhibition experiments. although no candidate with improved heparanase inhibitory activity over that of amodiaquine emerged from this subset, several structural requirements for the binding of an inhibitor to the active site of the enzyme were obtained. four mannich bases 331 of nitroxoline (fig. 63 ) were found to inhibit efficiently the activity of methionine aminopeptidase-1 from burkholderia pseudomallei with ic50 values ranging from low micromolar to 30 nm, and a few candidates in this series also showed in vitro growth inhibition of burkholderia thailandensis [487] . hexacyclic indole mannich bases 332 (r 1 ¼ h or ch 3 , nr 2 ¼ n(c 2 h 5 ) 2 , 1-pyrrolidinyl) and 333 (r 1 ¼ ch 3 , nr 2 ¼ 4morpholinyl) derived from annelated maleimidoindolodiazepines (fig. 63 ) were tested against a panel of 25 human protein kinases, but they were inactive against all of the tested enzymes at micromolar concentrations [488] . out of four synthesized acetylenic mannich bases 334 (nr 2 ¼ n(c 2 h 5 ) 2 , 1-pyrrolidinyl, n-allyl-n-methyl, n-(2dimethylaminoethyl)-n-methyl) derived from 7-(prop-2-ynyloxy) chromen-2-one (fig. 63) , three were inhibitors of squalene-hopene cyclase [489] . candidate 334 (nr 2 ¼ n-allyl-n-methyl) was half as potent as the hoffmanela roche's anticholesteremic drug ro 48-8071, which is an effective inhibitor of both squalene-and oxidosqualene cyclases that features the same secondary amino group in its structure. thiazolidinone c-mannich bases 335 (r 1 ¼ 4-ch 3 c 6 h 4 , 4-no 2 c 6 h 4 , 2-furyl, 3,4,5-(ch 3 ) 3 c 6 h 2 ; nr 2 ¼ n(c 2 h 5 ) 2 , 4morpholinyl, 4-methylpiperazinyl) (fig. 63) were evaluated as inhibitors of schistosoma mansoni cercarial elastase, but they were all inactive [490] . oxadiazolethione n-mannich bases 336 having a naphthalen-1ylmethyl residue at c-5 ( fig. 63 ) were all active against mushroom tyrosinase, and 6 to 10 times more potent than reference compound kojic acid [491] . the presence of a thione group able to chelate with copper, and the ability of the cyclic secondary amine to form extensive hydrophobic contacts within the binding site of tyrosinase appear to be responsible for the activity. another oxadiazolethione n-mannich base, namely 139m (table 2) , presented moderate inhibitory activity against urease within the series of compounds investigated, but no comparison with the activity of a well-established urease inhibitor was provided [201] . 19.1. ligands of 5-hydroxytryptamine receptors 5-hydroxytryptamine receptors (5-ht receptors), also known as serotonin receptors, belong to the group of g protein-coupled receptors (with the exception of 5-ht 3 , which is a ligand-gated ion channel). they are found in the central and peripheral nervous systems, and their function is to mediate both excitatory and inhibitory neurotransmission. 5-ht receptors are activated by their natural ligand, the neurotransmitter serotonin. mannich bases 245 (n ¼ 1 or 2) (fig. 44) were evaluated as ligands for the types of 5-ht receptors that could be involved in the mediation of the anticonvulsant effect of these compounds, but the candidates exhibited only moderate to low affinity for both 5-ht 1a (k i ¼ 81e370 nm) and 5-ht 2a receptors (k i ¼ 126e1370 nm) [383] . the nature of the spiranic cycloalkyl group did not influence serotonin receptor affinity significantly, although cyclohexylsubstituted candidates 245 were slightly more active than cyclopentyl-substituted analogues. the nature of the substituent in the aryl moiety at n-4 of piperazine ring modulates the selectivity towards one of these 5-ht receptors; thus, mannich bases 245 (r ¼ 2-och 3 ) showed the highest affinity for 5ht 1a receptors and the lowest affinity for 5-ht 2a receptors, while the highest 5-ht 2a receptor affinity was shown by mannich bases 245 (r ¼ 3-cf 3 ). in addition, computer-aided design of novel mannich bases of imidazoline-2,4-diones led to the identification of several compounds with potential dual affinity for 5ht 1a receptors and serotonin transporter, whose synthesis and evaluation finally led to candidates 337 (r ¼ h or f) (fig. 64) having the desired pharmacological profile [492] . a series of quinoxaline-2-carboxamides n-substituted with phenolic mannich bases moieties having either one or two aminomethyl functions have been synthesized and tested for 5-ht 3 receptor antagonistic activity in longitudinal muscle-myenteric plexus preparation from guinea pig ileum against 5-ht 3 agonist, 2-methyl-5-ht [493, 494] . candidates 338 (r 1 ¼ cl) (fig. 64 ) exhibited mild to moderate antagonist activity, and double mannich bases were generally less potent than their mono-mannich bases counterparts, but mannich base 338 (r 1 ¼ cl, r 2 ¼ h, nr 2 ¼ 4-methylpiperazin-1-yl) had 5-ht 3 receptor antagonistic activity comparable to that of reference compound ondansetron [493] . replacement of chlorine with methoxy led to less potent candidates 338 (r 1 ¼ och 3 ), whereas candidates with an ethoxy group at position 3 of quinoxaline ring were even less potent [494] . the presence of piperazines in the aminomethyl moiety of candidates 338 seemed to be more favorable for 5-ht 3 receptor antagonistic activity than the presence of other cyclic secondary amines. dopamine receptors are g protein-coupled receptors that are widely distributed in the brain, and whose primary endogenous ligand is the neurotransmitter dopamine. there are at least five subtypes of dopamine receptors, but d 1-2 receptor subtypes usually predominate, as they are 10e100 times more numerous than d [3] [4] [5] subtypes. discovery of l-745,870 339 [495] and fauc 113 340 [496] (fig. 65 ) as potent and selective d 4 receptor ligands has fueled the search for novel chemical entities having the ability to bind to dopamine receptors. based on the observation that these two ligands and many other dopamine receptor ligands feature a methylene bridge between the piperazine ring and the (hetero)aromatic part of the molecule, various analogues have been designed and synthesized. however, the majority of these analogues were obtained either through nucleophilic displacement by an appropriately substituted piperazine of a halogen atom from a halomethyl derivative of a selected (hetero)aromatic substrate, or through reductive amination of a formyl-substituted (hetero)aromatic substrate in the presence of a piperazine. literature search revealed a few examples when the mannich reaction was employed to synthesize the ligands to be evaluated for dopamine receptor binding ability. in addition to pyrrolo [2,3-b] pyridine and pyrazolo [1,5-a]pyridine ring systems used to in the generation of ligands 339 and 340, imidazo[1,2-a]pyridine is another example of an azaindole ring system that was aminomethylated to yield mannich bases 341 (fig. 65) [497] . receptor binding profiles of candidates 341 and several mono-mannich bases 342 derived from pyrrole ( fig. 65) were determined in vitro by measuring their ability to compete with [ 3 h]spiperone for the cloned human dopamine receptor subtypes d 2 long , d 2 short , d 3 and d 4.4 , while d 1 receptor affinities were measured employing an assay that used d 1 selective ligand [ 3 h]sch 23390 and porcine striatal membranes. all of the mannich bases 341 and 342 were selective ligands for the d 4 receptor subtype, and the candidates with an imidazo[1,2-a]pyridine scaffold were more potent than their counterparts having a pyrrole ring. the most potent mannich bases 341 (r ¼ 2-c 2 h 5 o, 2,3-cl 2 , 3-cf 3 ) showed an affinity for the dopamine d 4 receptor in the low nanomolar range, and their selectivity for this receptor subtype exceeded that of reference drug clozapine [497] . several small series of candidates comprising mannich bases 343, 344 and 345 (r 1 ¼ h or cl) having a pyrrolo[2,3-d]pyrimidine scaffold (fig. 65 ) were designed and evaluated as ligands for dopamine receptor subtypes d 1 , d 2 long , d 2 short , d 3 and d 4.4 , but they had no appreciable affinity for any of the dopamine receptors tested [498] . the strongest binding in these series was recorded for candidates 343 (r ¼ 2-ch 3 o) and 345 (r 1 ¼ h, r ¼ 2-ch 3 o) at dopamine d 4.4 receptor, with k i values of 2.4 and 1.9 nm, respectively. novel heteroaromatic scaffolds have been employed in the synthesis of mannich bases 346, 347 and 348 (fig. 65 ) as potential d 4 receptor ligands [499] . candidate 346 derived from pyrrolo[2,3c]pyridine ring system bound selectively at d 4.4 receptor (k i ¼ 6.4 nm). evaluation of mannich bases 347 generated from imidazo [1,2-c] pyrimidines and having various substituents at positions 2, 5 and 7 led to different results, depending on the nature and number of these substituents. thus, mannich base 347 (r 1 ¼ r 2 ¼ r 3 ¼ h) derived from the unsubstituted scaffold and all of the mannich bases 347 (r 1 ¼ ch 3 , r 2 ¼ r 3 ¼ h) obtained from 7methylimidazo[1,2-c]pyrimidine had no effect on dopamine d 4 receptor. the results for the binding assay for mannich bases derived from dimethyl-substituted imidazo [1,2-c] pyrimidines showed that candidates 347 (r 1 ¼ r 3 ¼ ch 3 , r 2 ¼ h) have binding affinities to dopamine d 4 receptor in the range of reference drug clozapine, while candidate 347 (r 1 ¼ r 2 ¼ ch 3 , r 3 ¼ h) is a weak ligand. further modifications, such as introduction of a carbethoxy group in the structure of candidates 347 (r 1 ¼ r 2 ¼ ch 3 , r 3 ¼ cooc 2 h 5 ), or two methoxy groups in mannich bases 347 (r 1 ¼ r 2 ¼ och 3 , r 3 ¼ h), led to compounds without affinity for dopamine d 4 receptor. in the series of mannich bases derived from 2,5,7-trimethylimidazo[1,2-c]pyrimidine, only candidate 347 (r 1 ¼ r 2 ¼ r 3 ¼ ch 3 , r ¼ 2-och 3 ) had good binding properties for the dopamine d 4 receptor, whereas another candidate 347 (r 1 ¼ r 2 ¼ r 3 ¼ ch 3 , r ¼ 4-och 3 ) exhibited a slight selectivity for dopamine d 3 receptor. use of pyrrolo [3,2-d] pyrimidine as scaffold led to some of the most potent ligands of dopamine d 4 receptor in this study (k i values between 2.4 and 3.8 nm). the nature of the amino group at position 2 of pyrrolo [3,2-d] pyrimidine scaffold modulates the activity; thus, mannich bases 348 (nr 2 ¼ 1pyrrolidinyl) had good affinities for dopamine d 4 receptor, but replacement of pyrrolidine with morpholine resulted in significant loss of dopamine d 4 receptor binding affinity. two novel indole mannich bases 59 (r ¼ 2-c 2 h 5 oc 6 h 4 , 2,3-cl 2 c 6 h 3 ) (fig. 11) were synthesized through direct aminomethylation and evaluated as ligands for several dopamine receptor subtypes, along with other heteroarylmethylpiperazines [500] . both candidates were potent and selective dopamine d 4 receptor ligands, and mannich base 59 (r ¼ 2-c 2 h 5 oc 6 h 4 ) was the most potent compound in this library (k i ¼ 0.03 nm). in addition, mannich base 59 (r ¼ 2,3-cl 2 c 6 h 3 ) was the most potent candidate having a 4-(2,3-dichlorophenyl)piperazine moiety, suggesting the importance of indole as (hetero)aromatic moiety in this type of dopamine d 4 receptor ligands. the effect on the affinity to d 2 , d 3 and d 4 dopamine receptor subtypes of replacement of 4-arylpiperazinyl in mannich bases with other monocyclic or bicyclic amine residues was also investigated [501] . mannich bases 349 (x ¼ ch or n) (fig. 66) derived from 3-(4-chlorophenyl)-8-azabicyclo[3.2.1]octan-3-ol as amine reagent in the mannich reaction had modest affinity and moderate selectivity for dopamine d 3 receptor subtype compared to d 2 and d 4 receptor subtypes. pyrrolidinol analogues 350 (x ¼ ch or n) (fig. 66 ) had poor binding affinities to all subtypes of dopamine receptors, while homopiperazine analogue 351 (fig. 66 ) had moderate binding affinity to dopamine d 4 receptor subtype (k i ¼ 18.6 nm). candidate 352 derived from 3,9-diazabicyclo[4.2.1] nonane ring system as amine reagent in the mannich reaction ( fig. 66 ) bound poorly to all types of dopamine receptor investigated in this study. although candidate 353 (fig. 66 ) derived from 2,5-diazabicyclo[2.2.1]heptane ring system as amine reagent in the mannich reaction had the highest d 3 receptor affinity of all the compounds tested in this paper (k i ¼ 11 nm), it also had poor selectivity towards d 3 (k i d2 ¼ 62 nm, k i d4 ¼ 69 nm). mannich base 354 derived from 2-(2-pyrimidinyl)piperazine (fig. 66 ) had modest binding affinity to dopamine d 4 receptor subtype (k i ¼ 56 nm), but good selectivity over d 2 and d 3 subtypes. thyroid receptors are nuclear receptors belonging to a superfamily whose members function as hormone activated transcription factors. the regulation of transcription for thyroid receptors is controlled by their natural ligand, the thyroid hormone. both unliganded and liganded thyroid receptors can bind to and regulate genes under the control of thyroid response elements, but the liganded thyroid receptor complex can also recruit a particular coactivator protein out of many available, with a view to steer the course of transcriptional regulation. high-throughput screening of a library of compounds identified a number of hits for inhibitors of the interaction between thyroid receptor and its coactivator src2 (steroid receptor coactivator 2), and two of these hit compounds were ketonic mannich bases 355 and 356 (fig. 67) [502] . these candidates represent a new class of thyroid receptor antagonists that have exceptional selectivity towards b isoform and are active in the presence of thyroid hormone, while being able to silence its signaling. mannich bases 355 and 356 are most likely covalently bound to thyroid receptor as a result of an alkylation process, thus inhibiting its hormone-induced gene transcription. subsequent preliminary sar showed that a hydrophobic moiety para to the ketone function in other ketonic mannich bases analogous to 355 and 356 is an important structural feature of potent inhibitors of the thyroid receptorecoactivator interaction [503] . a second series of candidates explored the effect that the nature of the amino group in ketonic mannich bases analogous to 355 and derived from 4-nhexylacetophenone has on the interaction between coregulatory protein src2 and both isoforms of thyroid receptors. all the synthesized candidates inhibited the interaction in the low micromolar range, with a roughly 2-fold selectivity towards isoform b. these ketonic mannich bases most likely function as prodrugs for the true active species, namely the a,b-unsaturated ketones resulted through deamination. therefore, a collection of enones having various substituents at the carbonecarbon double bond was also tested with a view to provide an insight on the mechanism of action of ketonic mannich bases as inhibitors of this interaction. the results showed that the inhibition of the interaction between thyroid receptor and coactivator protein src2 depends strongly on the substitution pattern at the carbonecarbon double bond in these a,b-unsaturated ketones. the most potent was the unsubstituted enone 357 (fig. 67) , which formally arises from 355 through deamination, whereas all other substituted enones were weaker inhibitors than 357. subsequent investigations confirmed that enone 357 is the actual inhibitor, and that compound 357 is generated within the binding site, where it remains bound until it reacts with one of the local cysteine residues [504] . in addition, an attempt to examine a complex between thyroid receptor b and mannich base 355 by x-ray crystallography led to the detection in the activation function-2 cleft of thyroid receptor b of enone 357 instead of mannich base 355. although enone 357 did not react rapidly with thyroid hormone, it positioned close to several cysteine residues. several other experiments showed that, once formed, enone 357 slowly alkylates nearby cys298 residue to occlude activation function-2 pocket of thyroid receptor b. significant improvement of pharmacological properties (especially potency and therapeutic index) of inhibitors of thyroid hormone receptor coactivator binding based on ketonic mannich bases was achieved with a series of novel candidates having in the aromatic ring electron withdrawing substituents associated with high efficacy, and a sulfonyl group to reduce cytotoxicity. also, piperazinone and 4-acetylpiperazine were used as preferred amine moieties with a view to minimize ion channel activity of these inhibitors [505] . the most potent compounds 358 and 359 (r ¼ 2,3-cl 2 or 2,5-cl 2 ) (fig. 67) showed outstanding thyroid hormone receptor coactivator interaction inhibitory potency, good therapeutic index, while no inhibition of kcl-stimulated depolarization of hek293-herg cells was observed for these mannich bases. androgen receptor is a ligand-regulated transcription factor in the nuclear receptor superfamily. the receptor, which represents an important molecular target for the treatment of prostate cancer, is activated through the binding of its two natural endogenous ligands, testosterone or 5a-dihydrotestosterone. subsequent activation of androgen-responsive genes can be blocked by androgen receptor antagonists through competitive inhibition. highthroughput screening of a structurally diverse chemical library comprising 16,000 synthetic and natural compounds led to the identification of 130 hit compounds that exhibited more than 85% competitive inhibition of 5a-dihydrotestosterone binding to androgen receptor [506] . mannich base 360 (r 1 ¼ r 2 ¼ ch 3 , r 3 ¼ c 6 h 5 ) (fig. 68 ) was selected for further development owing to its consistent androgen receptor antagonist activities in a cellbased assay using monkey kidney fibroblast cv-1 cells, and fortynine analogues were designed based on its b-amino ketone core structure. nine of these analogues showed higher binding affinity to androgen receptor than 5a-dihydrotestosterone, and evaluation of the enantiomers of candidate 360 (r 1 ¼ no 2 , r 2 ¼ cl, r 3 ¼ 2furyl) showed that the androgen receptor-modulating activity and binding resided with the dextrorotatory isomer. sar within this library of ketonic mannich bases revealed that the presence of chlorine as substituent r 2 , preferably para to the amino group, is important for androgen receptor antagonistic effects, while the presence of an electron-withdrawing group as substituent r 1 is crucial for high-affinity binding to the receptor. good androgen fig. 67 . mannich bases as inhibitors of the interaction between thyroid receptors and their coregulators. receptor binding activity was found among analogues having phenyl, 2-furyl and 2-thienyl as substituent r 3 , and mannich bases with heteroaryl moiety exhibited less cytotoxicity towards hela cells than mannich bases with r 3 ¼ (substituted)phenyl. candidate 360 (r 1 ¼ no 2 , r 2 ¼ cl, r 3 ¼ 2-furyl) inhibited the growth of sc3 cells (a mouse mammary cell line that responds well to androgens), while its effects on the proliferation of pc3 cells (a human prostate cancer cell line that lacks measurable androgen receptors) were very weak. mannich bases of type 360 were subsequently disclosed as selective non-steroidal antagonists of another member of the nuclear receptor superfamily, namely progesterone receptor, and sar within a collection of mannich bases 360 showed that coordinating effects of substituents r 1 and r 3 can modulate the potency and selectivity for progesterone receptor over androgen receptor [507] . mannich bases that modulate the activity of acetylcholine receptors have been the topic of two recent studies. two quaternary salts 361 (r ¼ ch 3 , allyl) derived from bis-aminomethylated pyrazinodiindole (fig. 68) were synthesized in order to probe their binding to the allosteric binding domain of muscarinic receptor m 2 [508] . these quaternary salts showed only slightly higher binding affinity to muscarinic m 2 receptor subtype than the corresponding parent double mannich bases, which in turn exhibited relatively poor allosteric potency. due to the structural similarity of candidates 361 and neuromuscular-blocking agents, their binding affinity to the muscle-type of the nicotinic acetylcholine receptors was also determined. thus, compound 361 (r ¼ ch 3 ) had a 34-fold higher affinity for the muscle type nicotinic acetylcholine receptor than for the allosteric site of m 2 receptors. double mannich bases 362 (nr 2 ¼ 1-piperidinyl, 2-methyl-1-piperidinyl, 1-azepanyl) derived from phthalamide (fig. 68) had a competitive antagonistic effect to acetylcholine on isolated guinea pig ileum that was poorer than that of reference compound atropine, and behaved as noncompetitive antagonists at higher concentration [509] . in addition, candidates 362 (nr 2 ¼ 1-piperidinyl, 2-methyl-1-piperidinyl, 1-azepanyl) antagonize the motor effect of oxotremorine in mice, while mannich base 362 (nr 2 ¼ 2,6-dimethyl-1-piperidinyl) was inactive in both tests. indole mannich base 59 (r ¼ phenethyl) (fig. 11 ) had moderate binding affinity to both sigma-1 (k i ¼ 14.2 nm) and sigma-2 (k i ¼ 55.8 nm) receptors, and can be considered as a potent, but non-selective ligand for sigma receptors [80] . ketonic mannich bases 363 (fig. 68) derived from cyclic ketones such as a-tetralone (x ¼ ch 2 ch 2 ), chromanone (x ¼ och 2 ), indanone (x ¼ ch 2 ) or benzosuberone (x ¼ (ch 2 ) 3 ) as substrates and either 4benzylpiperidine (z ¼ ch 2 ) or 4-benzylpiperazine (z ¼ n) as amine reagents in the mannich reaction were also evaluated for their affinity towards sigma-1 and sigma-2 receptors [510] . generally, 4-benzylpiperazine-containing mannich bases were higher-affinity sigma receptor ligands than the corresponding 4benzylpiperidine-containing analogues. compared to other alkylpiperidines or alkylpiperazines that were evaluated in this study, ketonic mannich bases 363 had only moderate affinity for sigma receptors. the presence of the carbonyl group in their structure appears to be detrimental, especially for the affinity to sigma-1 receptors, and the binding affinity seems to be influenced by the size of the saturated ring fused to the aromatic ring. thus, sixmembered candidates 363 are more potent than mannich bases 363 derived from indanone or benzosuberone. however, candidate 363 (x ¼ ch 2 ch 2 , z ¼ ch 2 ) was one of the most selective compounds in this study, with a selectivity towards sigma-2 receptors of approximately 0.1 (k i-s1 ¼ 24 nm, k i-s2 ¼ 3.4 nm). in contrast, mannich bases 363 derived from 4-benzylpiperazine were consistently better ligands for sigma-1 than for sigma-2 receptors. mannich bases of indoles substituted in the carbocyclic ring with a carboxamide group were evaluated as human histamine h 3 receptor antagonists [511] . preliminary analysis of the binding affinity of candidates 364 (r ¼ i-c 3 h 7 , c-c 4 h 7 , x ¼ ch 2 , o, nc 3 h 7 -i, nc 4 h 7 -c) (fig. 68) to human h 3 receptor with respect to different positional isomers within this series established a correlation between the 3,6-substitution pattern in 364 and good human h 3 receptor affinity, while the 3,4-substitution pattern was the least favorable for h 3 receptor binding affinity. the presence of piperidine and morpholine in the aminomethyl group led to compounds with excellent histamine h 3 receptor affinity, whereas the presence of 4-substituted piperazines in the aminomethyl group was not well tolerated. several mannich bases 364 of indoles with a 3,7substitution pattern also presented reasonable potency as human h 3 antagonists; in this case, the presence of a cyclobutyl residue in the piperazine ring in the carboxamide group seems to be more favorable for human histamine h 3 binding affinity than substitution with an isopropyl residue. in the search for new ligands able to discriminate among the three a 1 -adrenergic receptor subtypes, a series of mannich bases 365 (r ¼ ch 3 , n-c 3 h 7 , ch 2 c 6 h 5 , ch 2 c 6 h 11 -c, c 6 h 5 ) derived from 1,2,3,4-tetrahydro-4h-carbazol-4-ones (fig. 68) , that are structurally related to the potent a 1 -adrenergic receptor antagonist heat, were synthesized and evaluated [512] . as a general trend, all candidates showed lower affinities than heat for all three a 1 -adrenergic receptor subtypes, and replacement of tyramine with 4-(2substituted phenyl)piperazines did not enhance the affinity towards any subtype in particular. in addition, mannich bases 366 derived from 3-acetylindole and the same amines ( fig. 68 ) were designed as "open chain" analogues of candidates 365, and their evaluation showed a slight improvement in the affinity for all three a 1 -adrenergic receptor subtypes. starting from a hit obtained by screening a large library of compounds, and employing subsequent stepwise refinement of structural features, a series of mannich bases 367 (r ¼ (substituted) phenyl) of pyrazolones (fig. 68 ) was designed as ligands of cc chemokine receptor 3 (ccr3), a potential molecular target for treatment of allergic asthma [513] . the evaluation of binding to human ccr3 receptor of candidates 367 showed that most compounds display ic 50 values around 100 nm, and that only two of these mannich bases (r ¼ 4-fc 6 h 4 and 2-pyridinyl) bound more tightly to ccr3 than the initial hit compound (ic 50 ¼ 32 nm). because the lead compound 367 (r ¼ 4-fc 6 h 4 , ic 50 ¼ 20 nm) suffered from poor water solubility and metabolic stability, less lipophilic analogues were prepared by the introduction of ionizable groups in different parts of the molecule. replacement in the structure of 367 (r ¼ 4-fc 6 h 4 ) of the 4-chlorophenyl moiety with 4-fluorophenyl, 4-nitrophenyl, 4-sulfonamidophenyl, 4aminophenyl or pyridinyl moieties, as well as substitution of the 2,6-diflurophenyl moiety with pyridinyl or pyridinyl-n-oxide led to a second series of pyrazolone mannich bases 368 ( fig. 68) with improved solubility in water and enhanced metabolic stability. although structural modulations in the r 1 moiety generally decreased the binding affinity of candidates 368 to ccr3, modifications in the r 2 part afforded potent compounds (ic 50 ¼ 12 nm). two n-mannich bases 369 (r ¼ h or f) of a pyrazole derivative (fig. 68 ) were reported in a study that examined the interaction of a series of 4-heteroaryl-2-phenylquinolines with neurokinin nk-2 and nk-3 receptors, but they were inactive (k i > 10 mm) [514] . throughout the last decade, a large number of novel mannich bases have been synthesized and evaluated as potential treatments for a multitude of diseases and medical conditions, as prodrugs, or as molecules eliciting a response from biological targets. the vast amount of data concerning the structureeactivity relationship for mannich bases derived from structurally diverse substrates has added to previous knowledge, thus allowing better insight into the design of more effective drug candidates based on the aminomethylation reaction in the future. tremendous progress has been made in the field of anticancer agents and antimicrobials, and the last decade has witnessed the chemical modification of many biologically-active, naturally-occurring substrates or well established drugs by means of the mannich reaction with a view to improve their biological activity. as such, the mannich reaction has earned its rightful place as a powerful tool in medicinal chemistry, both for the synthesis of novel chemical entities endowed with various and interesting biological properties, and for the modification of physico-chemical properties of a candidate, that ultimately influence the candidate's biodisponibility, performance and pharmacological activity as a drug. advances in the chemistry of mannich bases further advances in the chemistry of mannich bases mannich bases: chemistry and uses effect of aminomethyl (n-mannich base) derivatization on the ability of s 6 -acetyloxymethyl-6-mercaptopurine prodrug to deliver 6-mercaptopurine through hairless mouse skin prodrugs e an efficient way to breach delivery and targeting barriers gilmer, b-aminoketones as prodrugs with phcontrolled activation anticancer and cytotoxic properties of mannich bases bioactivities of chalcones cytotoxic thiol alkylators sequential cytotoxicity: a theory evaluated using novel 2-[4-(3-aryl-2-propenoyloxy)phenylmethylene]cyclohexanones and related compounds evaluation of some mannich bases of cycloalkanones and related compounds for cytotoxic activity cytotoxic and anticancer activities of some 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides cytotoxic activities of mannich bases of chalcones and related compounds cytotoxic activities of mono and bis mannich bases derived from acetophenone against renca and jurkat cells cytotoxic activities of some mono and bis mannich bases derived from acetophenone in brine shrimp bioassay cytotoxicity of some azines of acetophenone-derived mannich bases against jurkat cells synthesis of some mannich bases with dimethylamine and their hydrazones and evaluation of their cytotoxicity against jurkat cells evaluation of the cytotoxicity of some mono-mannich bases and their corresponding azine derivatives against androgen-independent prostate cancer cells cytotoxic and anticonvulsant aryloxyaryl mannich bases and related compounds biological evaluation and structureactivity relationships of bis-(3-aryl-3-oxo-propyl)-methylamine hydrochlorides and 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinol hydrochlorides as potential cytotoxic agents and their alkylating ability towards cellular glutathione in human leukemic t cells effect of some bis mannich bases and corresponding piperidinols on dna topoisomerase i the design and cytotoxic evaluation of some 1-aryl-3-isopropylamino-1-propanone hydrochlorides towards human huh-7 hepatoma cells cytotoxicity of 1-aryl-3-butylamino-1-propanone hydrochlorides against jurkat and l6 cells synthesis of 1-aryl-3-phenethylamino-1-propanone hydrochlorides as possible potent cytotoxic agents biological activity of 1-aryl-3-phenethylamino-1-propanone hydrochlorides and 3-aroyl-4-aryl-1-phenethyl-4-piperidinols on pc-3 cells and dna topoisomerase i enzyme effect of acetophenone derived mannich bases on cellular glutathione level in jurkat cells. a possible mechanism of action syntheses and stability studies of some mannich bases of acetophenones and evaluation of their cytotoxicity against jurkat cells effects of mannich bases on cellular glutathione and related enzymes of jurkat cells in culture conditions the effects of some mannich bases on heat shock proteins hsc70 and grp75, and thioredoxin and glutaredoxin levels in jurkat cells cytotoxic mannich bases of 1-arylidene-2-tetralones cytotoxic and topographical properties of 6-arylidene-2-dimethylaminomethylcyclohexanone hydrochlorides and related compounds potential role of nmyristoyltransferase in cancer inhibition of protein n-myristoylation: a therapeutic protocol in developing anticancer agents synthesis and cytotoxic and mechanistic studies of a-arylidenecyclohex(pent)anone or aarylcyclohexanone a'-mannich bases and their deoxo bisaryl cyclohex(pent) ene analogs synthesis and anticancer activity of 2-alkylaminomethyl-5-diaryl-methylenecyclopentanone hydrochlorides and related compounds dimmock, a-substituted 1-aryl-3-dimethylaminopropanone hydrochlorides: potent cytotoxins towards human widr colon cancer cells 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides and related adducts: a quest for selective cytotoxicity for malignant cells synthesis of 4 0 -hydroxy-3 0 -piperidinomethylchalcone derivatives and their cytotoxicity against pc-3 cell lines synthesis and cytotoxicity of novel 3-aryl-1-(3 0 -dibenzylaminomethyl-4 0 -hydroxyphenyl)-propenones and related compounds design, synthesis and in vitro cytotoxic activity evaluation of new mannich bases design, synthesis, and biological evaluation of mannich bases of heterocyclic chalcone analogs as cytotoxic agents 1-(3-aminomethyl-4-hydroxyphenyl)-3-pyridinyl-2-propen-1-ones: a novel group of tumour-selective cytotoxins preparation of aminoalkyl substituted chalcones for use in anticancer and antimalarial pharmaceutical compositions preparation of a series of novel bichalcones linked with a 1,4-dimethylenepiperazine moiety and examination of their cytotoxicity new bichalcone analogs as nf-kb inhibitors and as cytotoxic agents inducing fas/cd95-dependent apoptosis azidothymidine is effective against human multiple myeloma: a new use for an old drug hłado n, synthesis and anticancer activity of 5 0 -chloromethylphosphonates of 3 0 -azido-3 0 -deoxythymidine (azt) antileukemic activity and cellular metabolism of the aryl phosphate derivative of bromo-methoxy zidovudine (compound whi-07) synthesis and in vitro cytotoxic activity evaluation of novel mannich bases and modified azt derivatives possessing mannich base moieties via click chemistry synthesis and pharmacological exploitation of clioquinol-derived copper-binding apoptosis inducers triggering reactive oxygen species generation and mapk pathway activation cytotoxicity and antimicrobial activity of some naphthol derivatives synthesis and cytotoxicity evaluation of some 8-hydroxyquinoline derivatives synthesis and structure-activity relationship study of 8-hydroxyquinoline-derived mannich bases as anticancer agents design, synthesis and bioevaluation of novel candidate selective estrogen receptor modulators recent advancement in nonsteroidal aromatase inhibitors for treatment of estrogen-dependent breast cancer facile synthesis of chrysin-derivatives with promising activities as aromatase inhibitors nitrogen-containing apigenin analogs: preparation and biological activity synthesis and antiproliferative activity of oxazinocarbazole and n,n-bis(carbazolylmethyl)amine derivatives synthesis, antitumour activity and structureeactivity relationships of 5h-benzo[b]carbazoles display and analysis of patterns of differential activity of drugs against human tumor cell lines: development of mean graph and compare algorithm 10-anthradiquinone as precursor for antitumor compounds the natural anticancer agent plumbagin induces potent cytotoxicity in mcf-7 human breast cancer cells by inhibiting a pi-5 kinase for ros generation anti-tumor effects of novel 5-o-acyl plumbagins based on the inhibition of mammalian dna replicative polymerase activity inhibitory effect of novel 5-o-acyl juglones on mammalian dna polymerase activity, cancer cell growth and inflammatory response cytotoxic activity of naphthoquinones with special emphasis on juglone and its 5-o-methyl derivative antiproliferative activity of synthetic naphthoquinones related to lapachol. first synthesis of 5-hydroxylapachol novel platinum(ii) complexes of 3-(aminomethyl)naphthoquinone mannich bases: synthesis, crystal structure and cytotoxic activities exploring the dna binding/cleavage, cellular accumulation and topoisomerase inhibition of 2-hydroxy-3-(aminomethyl)-1,4-naphthoquinone mannich bases and their platinum(ii) complexes novel 3-(aminomethyl)naphthoquinone mannich base-platinum(iv) complexes: synthesis, characterization, electrochemical and cytotoxic studies one-pot synthesis and cytotoxicity studies of new mannich base derivatives of polyether antibiotic e lasalocid acid novel hexacyclic camptothecin derivatives. part 1: synthesis and cytotoxicity of camptothecins with an a-ring fused 1,3-oxazine ring optimization of tocotrienols as antiproliferative and antimigratory leads quinone methides tethered to naphthalene diimides as selective g-quadruplex alkylating agents hybrid ligandalkylating agents targeting telomeric g-quadruplex structures synthesis and biological activities of quinazoline derivatives with ortho-phenol-quaternary ammonium salt groups dna binding, antiviral activities and cytotoxicity of new furochromone and benzofuran derivatives synthesis and biological evaluation of 1,3-dihydroxyxanthone mannich base derivatives as potential antitumor agents synthesis and in vitro evaluation of novel indole-based sigma receptors ligands synthesis and cytotoxic activity of novel 3-methyl-1-[(4-substituted-1-piperazinyl)methyl]-1h-indole derivatives design, synthesis, and biological evaluation of indole-based 1,4-disubstituted piperazines as cytotoxic agents amino derivatives of indole as potent inhibitors of isoprenylcysteine carboxyl methyltransferase functionalized indoleamines as potent, drug-like inhibitors of isoprenylcysteine carboxyl methyltransferase (icmt) 3-aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione for circumvention of anticancer drug resistance synthesis and structureeactivity relationship studies of naphtho[2,3-f]indole-5,10-dione aminoalkyl derivatives: a new class of topoisomerase i inhibitors synthesis of 4-substituted 3-[3-(dialkylaminomethyl)indol-1-yl]maleimides and study of their ability to inhibit protein kinase c-a, prevent development of multiple drug resistance of tumor cells and cytotoxicity synthesis and sar of novel 4-morpholinopyrrolopyrimidine derivatives as potent phosphatidylinositol 3-kinase inhibitors cytotoxic and anticancer activities of isatin and its derivatives: a comprehensive review from synthesis and in-vitro cytotoxicity evaluation of gatifloxacin mannich bases hybrid pharmacophore design and synthesis of isatinebenzothiazole analogs for their anti-breast cancer activity synthesis of novel isatin-thiazoline and isatin-benzimidazole conjugates as anti-breast cancer agents design and synthesis of anti-breast cancer agents from 4-piperazinylquinoline: a hybrid pharmacophore approach hydroxyphenyl)-3-substituted-2,3-dihydro-1,3,4-oxadiazole-2-thione derivatives: promising anticancer agents synthesis of some novel 3,5-disubstituted 1,3,4-oxadiazole derivatives and anticancer activity on eac animal model synthesis, quantitative structure-activity relationship and biological evaluation of 1,3,4-oxadiazole derivatives possessing diphenylamine moiety as potential anticancer agents synthesis, antitumor and antimicrobial activity of novel 1-substituted phenyl-3-[3-alkylamino(methyl)-2-thioxo-1,3,4-oxadiazol-5-yl]-b-carboline derivatives synthesis and antitumor activity of fluoroquinolone c3-isostere derivatives: oxadiazole mannich base derivatives synthesis, characterization and in vitro cytotoxic properties of some new schiff and mannich bases in hep g2 cells design, synthesis and antitumor activities of fluoroquinolone c-3 heterocycles (iv): s-triazole schiffemannich bases derived from ofloxacin facile synthesis and quantitative structureeactivity relationship study of antitumor active 2-(4-oxo-thiazolidin-2-ylidene)-3-oxo-propionitriles synthesis and biological activity evaluation of 5-pyrazoline substituted 4-thiazolidinones synthesis, xray crystallographic analysis, and antitumor activity of n-(benzothiazole-2-yl)-1-(fluorophenyl)-o,o-dialkyl-a-aminophosphonates synthesis and biological activities of aaminophosphonates derivatives containing thieno[3,2-c]pyridine (in chinese) synthesis, antimicrobial and anticancer activities of a novel series of diphenyl 1-(pyridin-3-yl) ethylphosphonates design and one-pot synthesis of a-aminophosphonates and bis(aaminophosphonates) by iron(iii) chloride and cytotoxic activity synthesis, antiproliferative activity in cancer cells and theoretical studies of novel 6a,7b-dihydroxyvouacapan-17b-oic acid mannich base derivatives synthesis and anti-tumor activities of novel synthesis and cytotoxicity studies of novel dimethylamino-functionalised and n-heteroaryl-substituted titanocene anticancer drugs: synthesis and cytotoxicity studies synthesis and cytotoxicity studies of new dimethylamino-functionalised and indolylsubstituted titanocene anti-cancer drugs synthesis and cytotoxicity studies of new dimethylamino-functionalized and azolesubstituted titanocene anticancer drugs synthesis and preliminary cytotoxicity studies of achiral indolyl-substituted titanocenes multidrug resistance reverting activity and antitumor profile of new phenothiazine derivatives synthesis of antitumoractive betulinic acid-derived hydroxypropargylamines by copper-catalyzed mannich reactions cytotoxic betulin-derived hydroxypropargylamines trigger apoptosis doxoform and daunoform: anthracyclineformaldehyde conjugates toxic to resistant tumor cells doxsaliform: a novel n-mannich base prodrug of a doxorubicin formaldehyde conjugate design, synthesis, and biological evaluation of doxorubicin-formaldehyde conjugates targeted to breast cancer cells antiestrogen binding site and estrogen receptor mediate uptake and distribution of 4-hydroxytamoxifen-targeted doxorubicin-formaldehyde conjugate in breast cancer cells rational design and synthesis of androgen receptortargeted nonsteroidal anti-androgen ligands for the tumor-specific delivery of a doxorubicin-formaldehyde conjugate studies of targeting and intracellular trafficking of an anti-androgen doxorubicin-formaldehyde conjugate in pc-3 prostate cancer cells bearing androgen receptor-gfp chimera doxorubicin-formaldehyde conjugates targeting a v b 3 integrin poly (ethylene glycol) prodrug for anthracyclines via n-mannich base linker: design, synthesis and biological evaluation synthesis and invitro antitumor activities of some mannich bases of 9-alkyl-1,2,3,4-tetrahydrocarbazole-1-ones synthesis and biological evaluation of novel mannich bases of 2-arylimidazo [2,1-b]benzothiazoles as potential anti-cancer agents cytotoxic mannich bases of 6-(3-aryl-2-propenoyl)-2(3h)-benzoxazolones new synthetic chalcones: cytotoxic mannich bases of 6-(4-chlorocinnamoyl)-2(3h)-benzoxazolone synthesis and cytotoxicity of novel hexahydrothieno-cycloheptapyridazinone derivatives synthesis and antibacterial study of unsaturated mannich ketones synthesis and antibacterial activity of fused mannich ketones novel mannich ketones of oxazolidinones as antibacterial agents synthesis and biological evaluation of a novel series of 2,2-bisaminomethylated aurone analogues as anti-inflammatory and antimicrobial agents evaluation of antimicrobial activities of several mannich bases and their derivatives synthesis and biological evaluation of aminoketones highly efficient one-pot synthesis, antimicrobial and docking studies of newer b-amino carbonyl derivatives catalyzed by silica sulfuric acid synthesis of b-amino carbonyl derivatives of coumarin and benzofuran and evaluation of their biological activity vuki cevi c, antibacterial 3-(arylamino)-1-ferrocenylpropan-1-ones: synthesis, spectral, electrochemical and structural characterization synthesis and characterization of some mannich bases as potential antimicrobial agents synthesis, characterization and antimicrobial evaluation of copper(ii) complexes of 5-tert-butyl-pyrocatechin-derived mannich bases synthesis and microbiological evaluation of mannich bases derived from 4,6-diacetylresorcinol mannich reaction derivatives of novobiocin with modulated physiochemical properties and their antibacterial activities novel aminonaphthoquinone mannich bases derived from lawsone and their copper(ii) complexes: synthesis, characterization and antibacterial activity synthesis, antiinflammatory and antimicrobial activity of some new 1-(3-phenyl-3,4-dihydro-2h-1,3-benzoxazin-6-yl)ethanone derivatives an eco-friendly synthesis and antimicrobial activities of dihydro-2h-benzo-and naphtho-1,3-oxazine derivatives synthesis and antibacterial evaluation of benzazoles tethered dihydro[1,3]oxazines ]oxazine derivatives catalyzed by zirconyl chloride and evaluation of its biological activities biocidal activity of some mannich base cationic derivatives some electrophilic substitution reactions on 1-substituted-3-acetyl/carbethoxy-5-hydroxy-2-methylindole and the antimicrobial activity of these new indole derivatives mannich base derivatives of 3-hydroxy-6-methyl-4h-pyran-4-one with antimicrobial activity a study of cytotoxicity of novel chlorokojic acid derivatives with their antimicrobial and antiviral activities synthesis and biological activities of new mannich bases of chlorokojic acid derivatives design, synthesis and in vivo/ in vitro screening of novel chlorokojic acid derivatives mannich bases of 7-piperazinylquinolones and kojic acid derivatives: synthesis, in vitro antibacterial activity and in silico study synthesis and antimicrobial screening of novel mannich bases of isatin derivative synthesis and antimicrobial evaluation of some novel trisubstituted s-triazine derivatives based on isatinimino, sulphonamido and azacarbazole synthesis and antimicrobial screening of certain novel mannich bases bearing 1,8-naphthyridine moiety synthesis and antimicrobial activities of oxadiazoles, phthalazines and indolinones synthesis and antimicrobial activity of mannich bases of isatin and its derivatives with 2-[(2,6-dichlorophenyl) amino]phenylacetic acid synthesis, antimicrobial screening and beta lactamase inhibitory activity of 3-(3-chloro-4-fluorophenylimino)indolin-2-one and 5-chloroindolin-2-one derivatives, turk synthesis, antiviral and antibacterial activities of isatin mannich bases synthesis and bioevaluation of schiff and mannich bases of isatin derivatives with 4-amino-5-benzyl-2,4-dihydro-3h-1,2,4-triazole-3-thione synthesis, characterization and in vitro antimicrobial activity of some novel 5-substituted schiff and mannich base of isatin derivatives synthesis and antimicrobial activity of novel 5-(1-adamantyl)-2-aminomethyl-4-substituted-1,2,4-triazoline-3-thiones microbiologically active mannich bases derived from 1,2,4-triazoles. the effect of c-5 substituent on antibacterial activity synthesis and antimicrobial activity of thiosemicarbazides, s-triazoles and their mannich bases bearing 3-chlorophenyl moiety synthesis and antibacterial activity of some novel n2-hydroxymethyl and n2-aminomethyl derivatives of 4-aryl-5-(3-chlorophenyl)-2,4-dihydro-3h-1,2,4-triazole-3-thione synthesis and in vitro activity of 1,2,4-triazole-ciprofloxacin hybrids against drug-susceptible and drug-resistant bacteria synthesis, characterization and antibacterial activity of some triazole mannich bases carrying diphenylsulfone moieties synthesis of some new s-alkylated 1,2,4-triazoles, their mannich bases and their biological activities synthesis and biological activities of some novel aminomethyl derivatives of 4-substituted-5-(2-thienyl)-2,4-dihydro-3h-1,2,4-triazole-3-thiones design, synthesis and antimicrobial activities of some azole derivatives synthesis of some new 1,2,4-triazoles, their mannich and schiff bases and evaluation of their antimicrobial activities syntheses and biological activities of new hybrid molecules containing different heterocyclic moieties alpay karao glu, preparation and antimicrobial activity evaluation of some quinoline derivatives containing an azole nucleus convenient one pot synthesis and antibacterial evaluation of some new mannich bases carrying 1,2,4-triazolyl moiety synthesis and antimicrobial activities of some new biheterocyclic compounds containing 1,2,4-triazol-3-one and 1,3,4-thiadiazole moieties synthesis of some new 1,3,4-thiadiazol-2-ylmethyl-1,2,4-triazole derivatives and investigation of their antimicrobial activities synthesis and biological activities of methylenebis-4h-1,2,4-triazole derivatives regioselective reaction: synthesis, characterization and pharmacological studies of some new mannich bases derived from 1,2,4-triazoles el-emam, synthesis, antimicrobial and anti-inflammatory activities of novel 5-(1-adamantyl)-4-[(arylidene)amino]-3-mercapto-1,2,4-triazoles and related derivatives convenient one pot synthesis and antimicrobial evaluation of some new mannich bases carrying 4-methylthiobenzyl moiety synthesis and biological activity of schiff and mannich bases bearing 2,4-dichloro-5-fluorophenyl moiety synthesis of some new 1,2,4-triazoles starting from isonicotinic acid hydrazide and evaluation of their antimicrobial activities synthesis, antiinflammatory, analgesic, and antibacterial activities of some triazole, triazolothiadiazole, and triazolothiadiazine derivatives synthesis and pharmacological evaluation of clubbed isopropylthiazole derived triazolothiadiazoles, triazolothiadiazines and mannich bases as potential antimicrobial and antitubercular agents regioselective reaction: synthesis of novel mannich bases derived from 3-(4,6-disubstituted-2-thiomethylpyrimidyl)-4-amino-5-mercapto-1,2,4-triazoles and their antimicrobial properties new class of triazole derivatives and their antimicrobial activity synthesis, characterization, and biological activity of novel schiff and mannich bases of 4-amino-3-(n-phthalimidomethyl)-1,2,4-triazole-5-thione alpay karao glu, reduction, mannich reaction and antimicrobial activity evaluation of some new 1,2,4-triazol-3-one derivatives preparation and antimicrobial activity evaluation of some new bi-and triheterocyclic azoles synthesis and biological evaluation of some 1,3,4-oxadiazole derivatives synthesis, characterization and antimicrobial activity of some disubstituted 1,3,4-oxadiazoles carrying 2-(aryloxymethyl)phenyl moiety synthesis and antimicrobial activity of new 5-(2-thienyl)-1,2,4-triazoles and 5-(2-thienyl)-1,3,4-oxadiazoles and related derivatives synthesis, antimicrobial and cytotoxic activities of some novel thiazole clubbed 1,3,4-oxadiazoles synthesis and antimicrobial activity of linked heterocyclics containing pyrazole and oxadiazoles synthesis and antimicrobial studies of some mannich bases carrying imidazole moiety synthesis and antimicrobial activity of some new 5-(3-chloro-1-benzothiophen-2-yl)-1,3,4-oxadiazole-2-thiol and their derivatives synthesis, antimicrobial and antiinflammatory activities of 1,3,4-oxadiazoles linked to naphtho[2,1-b]furan antimicrobial and antiurease activities of newly synthesized morpholine derivatives containing an azole nucleus synthesis and antimicrobial activities of some new 1,2,4-triazole derivatives synthesis of novel nalidixic acid-based 1,3,4-thiadiazole and 1,3,4-oxadiazole derivatives as potent antibacterial agents synthesis, characterization and antimicrobial activity of novel 3,5-disubstituted-1,3,4-oxadiazole-2-ones synthesis of mannich bases of some 2,5-disubstituted 4-thiazolidinones and evaluation of their antimicrobial activities synthesis, characterization and evaluation of antimicrobial activity of mannich bases of some 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones novel 6,8-dibromo-4(3h)quinazolinone derivatives of antibacterial and anti-fungal activities synthesis of 3-{4-[4-dimethylamino-6-(4-methyl-2-oxo-2h-chromen-7-yloxy)-[1,3,5]triazin-2-ylamino]-phenyl}-2-phenyl-5-(4-pyridin-2-yl-piperazin-1-ylmethyl)-thiazolidin-4-one and their biological evaluation synthesis and biological activity of 3,4-dihydropyrimidine-2-thione aminomethylene derivatives based on the alkaloid cytosine synthesis and in vitro study of biological activity of heterocyclic n-mannich bases of 3,4-dihydropyrimidine-2(1h)-thiones synthesis and in vitro study of biological activity of heterocyclic n-mannich bases synthesis and in vitro study of novel mannich bases as antibacterial agents synthetic, spectral, antimicrobial and qsar studies on novel mannich bases of glutarimides evaluation of antimicrobial activity and qsar study of a molecule library of the mannich bases of glutarimides syntheses, spectral, crystallographic, antimicrobial, and antioxidant studies of few mannich bases synthesis and biological study of medicinally important mannich bases derived from 4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,6,10,12,12a-pentahydroxynaphthacenecarboxamide hydrophobic vancomycin derivatives with improved adme properties: discovery of telavancin in vitro activity of telavancin against resistant gram-positive bacteria telavancin, a multifunctional lipoglycopeptide, disrupts both cell wall synthesis and cell membrane integrity in methicillinresistant staphylococcus aureus exploring the positional attachment of glycopeptide/b-lactam heterodimers vancomycin derivatives iodine catalyzed three-component synthesis of b-amino-b-keto-esters and their antimicrobial activity deep, synthesis, characterization and antimicrobial evaluation of novel derivatives of isoniazid synthesis and evaluation of some novel derivatives of 2-propoxybenzylideneisonicotinohydrazide for their potential antimicrobial activity synthesis and antimicrobial screening of novel series of imidazo[1,2-a]pyridine derivatives synthesis and evaluation of antibacterial and antitubercular activities of some novel imidazo synthesis, antimicrobial evaluation and qsar study of some 3-hydroxypyridine-4-one and 3-hydroxypyran-4-one derivatives synthesis of novel biologically active methylene derivatives of sydnones synthesis, characterization, and antimicrobial screening of some mannich base sydnone derivatives facile syntheses of mannich bases of 3-[p-(5-arylpyrazolin-3-yl)phenyl]sydnones, as anti-tubercular and anti-microbial agents, under ionic liquid/tetrabutylammonium bromide catalytic conditions copper(ii) complex with the tridentate ligand n,n-bis(2-ethyl-4-methylimidazol-5-ylmethyl)phenylethylamine (biaq). x-ray crystal structure and biological activity on bacillus subtilis of synthesis, sar study and evaluation of mannich and schiff bases of pyrazol-5(4h)-one moiety containing 3-(hydrazinyl)-2-phenylquinazolin-4(3h)-one design, synthesis, antibacterial activity and physicochemical parameters of novel n-4-piperazinyl derivatives of norfloxacin in vitro study of some medicinally important mannich bases derived from antitubercular agent microwave-assisted synthesis of some novel and potent antibacterial and antifungal compounds with biological screening synthesis and antimicrobial and antioxidant activities of simple saccharin derivatives with nbasic side chains synthesis and antimicrobial activity of 10-arylaminomethyl-3-methoxyphenothiazine-9-carboxylic acid in vitro antitubercular and antimicrobial activities of 1-substituted quinoxaline-2,3(1h,4h)-diones synthesis of some new thioxoquinazolinone derivatives and a study on their anticonvulsant and antimicrobial activities synthesis and anti bacterial and anti-ulcer evaluation of new s-mannich bases of 4,6-diaryl-3,4-dihydropyrimidin-2(1h)-thiones world health organization antimycobacterial arylidenecyclohexanones and related mannich bases methoxyphenylcarbonyloxy)benzylidene]-6-dimethylaminomethyl cyclohexanone hydrochloride: a mannich base which inhibits the growth of some drug-resistant strains of mycobacterium tuberculosis major roles of isocitrate lyase and malate synthase in bacterial and fungal pathogenesis mycobacterium tuberculosis isocitrate lyases 1 and 2 are jointly required for in vivo growth and virulence isocitrate lyase: a potential target for anti-tubercular drugs identification of mannich base as a novel inhibitor of mycobacterium tuberculosis isocitrate by high-throughput screening synthesis and in vitro and in vivo antimycobacterial activity of isonicotinoyl hydrazones 4h-pyran-4-one derivatives: leading molecule for preparation of compounds with antimycobacterial potential molecular modeling and antimycobacterial studies of mannich bases: 5-hydroxy-2-methyl-4h-pyran-4-ones bactericidal activities of the pyrrole derivative bm212 against multidrug-resistant and intramacrophagic mycobacterium tuberculosis strains synthesis and microbiological activities of pyrrole analogs of bm 212, a potent antitubercular agent new pyrrole derivatives as antimycobacterial agents analogs of bm212 importance of the thiomorpholine introduction in new pyrrole derivatives as antimycobacterial agents analogues of bm 212 antimycobacterial compounds. new pyrrole derivatives of bm212 antimycobacterial compounds. optimization of the bm 212 structure, the lead compound for a new pyrrole derivative class antimycobacterial agents. novel diarylpyrrole derivatives of bm212 endowed with high activity toward mycobacterium tuberculosis and low cytotoxicity botta, 1,5-diphenylpyrrole derivatives as antimycobacterial agents. probing the influence on antimycobacterial activity of lipophilic substituents at the phenyl rings -diaryl-2-ethyl pyrrole derivatives as antimycobacterial agents: design, synthesis, and microbiological evaluation identification of a novel pyrrole derivative endowed with antimycobacterial activity and protection index comparable to that of the current antitubercular drugs streptomycin and rifampin improved bm212 mmpl3 inhibitor analogue shows efficacy in acute murine model of tuberculosis infection mmpl3 is the cellular target of the antitubercular pyrrole derivative bm212 pharmacophore assessment through 3-d qsar: evaluation of the predictive ability on new derivatives by the application on a series of antitubercular agents bm 212 and its derivatives as a new class of antimycobacterial active agents new pyrroles with potential antimycobacterial, antifungal and selective cox-2 inhibiting activities. synthetic methodologies new derivatives of bm212: a class of antimycobacterial compounds based on the pyrrole ring as a scaffold developing pyrrole-derived antimycobacterial agents: a rational lead optimization approach pyrrole derivatives as antimycobacterial compounds, us patent 7 antitubercular agents. part 7: a new class of diarylpyrroleeoxazolidinone conjugates as antimycobacterial agents organocatalytic multicomponent reaction for the acquisition of a selective inhibitor of mptpb, a virulence factor of tuberculosis novel 1-(4-substituted benzylidene)-4-(1-(substituted methyl)-2,3-dioxoindolin-5-yl)semicarbazide derivatives for use against mycobacterium tuberculosis h37rv (atcc 27294) and mdr-tb strain synthesis, anti-hiv and antitubercular activities of lamivudine prodrugs synthesis and antituberculosis activity of 5-methyl/trifluoromethoxy-1h-indole-2,3-dione 3-thiosemicarbazone derivatives synthesis and structureeantituberculosis activity relationship of 1h-indole-2,3-dione derivatives gatifloxacin derivatives: synthesis, antimycobacterial activities, and inhibition of mycobacterium tuberculosis dna gyrase synthesis and antimycobacterial evaluation of various 7-substituted ciprofloxacin derivatives synthesis and in vitro antimycobacterial activity of 8-och 3 ciprofloxacin methylene and ethylene isatin derivatives synthesis and in vitro antimycobacterial activity of moxifloxacin methylene and ethylene isatin derivatives antimycobacterial activity of new 3-substituted 5-(pyridin-4-yl)-3h-1,3,4-oxadiazol-2-one and 2-thione derivatives. preliminary molecular modeling investigations antimycobacterial activity of new 3,5-disubstituted 1,3,4-oxadiazol-2(3h)-one derivatives. molecular modeling investigations oxadiazole mannich bases: synthesis and antimycobacterial activity augustynowicz-kope c, synthesis and tuberculostatic activity of some 2-piperazinmethylene derivatives 1,2,4-triazole-3-thiones synthesis and evaluation of antitubercular activity of imidazo mannich bases and novel benzothiazole derivatives of imidazo[2,1-b]-1,3,4-thiadiazoles and their biological evaluation synthesis & evaluation of antitubercular activity of novel mannich bases of imidazo newer tetracycline derivatives: synthesis, anti-hiv, antimycobacterial activities and inhibition of hiv-1 integrase synthesis of pyrazinamide mannich bases and their antitubercular properties efavirenz mannich bases: synthesis, anti-hiv and antitubercular activities indole mannich bases and their antimycobacterial effect synthesis of novel isothiazolopyridines and their in vitro evaluation against mycobacterium and propionibacterium acnes studies on pyrazine derivatives. 39. synthesis, reactions, and tuberculostatic activity of 3 epidemiology of invasive mycoses in north america antifungal activity of some mono, bis and quaternary mannich bases derived from acetophenone antimicrobial evaluation of some mannich bases of acetophenones and representative quaternary derivatives antifungal evaluation of bis mannich base derived from acetophenones and their corresponding piperidinols and stability studies synthesis and antifungal activity of 1-aryl-3-phenethylamino-1-propanone hydrochlorides and 3-aroyl-4-aryl-1-phenethyl-4-piperidinols synthesis and antifungal evaluation of 1-aryl-2-[(dimethylamino)methyl]-2-propen-1-one hydrochlorides antifungal unsaturated cyclic mannich ketones and amino alcohols: study of mechanism of action antifungal activity of fused mannich ketones triggers an oxidative stress response and is cap1-dependent in candida albicans synthesis and antifungal activity of 3-substituted thiochromanones deep, synthesis, characterization and evaluation of mannich bases as potent antifungal and hydrogen peroxide scavenging agents mannich reaction: an approach for the synthesis of water soluble mulundocandin analogues evaluation of bioactivities of chlorokojic acid derivatives against dermatophytes couplet with cytotoxicity synthesis and evaluation of anticonvulsant and antimicrobial activities of 3-hydroxy-6-methyl-2-substituted 4h-pyran-4-one derivatives synthesis and studies of triazolothiadiazines. an approach toward new biologically active heterocyclic compounds, phosphorus ecofriendly synthesis of novel antifungal (thio)barbituric acid derivatives world health organization malaria isoquine and related amodiaquine analogues: a new generation of improved 4-aminoquinoline antimalarials candidate selection and preclinical evaluation of ntert-butyl isoquine (gsk369796), an affordable and effective 4-aminoquinoline antimalarial for the 21st century comparative preclinical drug metabolism and pharmacokinetic evaluation of novel 4-aminoquinoline anti-malarials antimalarial activity of isoquine against kenyan plasmodium falciparum clinical isolates and association with polymorphisms in pfcrt and pfmdr1 genes mimicking the intramolecular hydrogen bond: synthesis, biological evaluation, and molecular modeling of benzoxazines and quinazolines as potential antimalarial agents synthesis and in vitro and in vivo antimalarial activity of novel 4-anilinoquinoline mannich base derivatives synthesis and antimalarial activity evaluation of some isoquine analogues synthesis and antimalarial activity study of some new mannich bases of 7-chloro-4-aminoquinoline novel amodiaquine congeners as potent antimalarial agents synthesis and antimalarial activity of new isotebuquine analogues review of pyronaridine anti-malarial properties and product characteristics determination of the physicochemical properties of pyronaridine e a new antimalarial drug absorption, distribution, excretion, and pharmacokinetics of 14 c-pyronaridine tetraphosphate in male and female spra-gueedawley rats in vitro interactions between piperaquine, dihydroartemisinin, and other conventional and novel antimalarial drugs, antimicrob anti-malarial efficacy of pyronaridine and artesunate in combination in vitro and in vivo targeting of hematin by the antimalarial pyronaridine pyrido [3,2-b]indol-4-yl-amine e synthese und prüfung auf wirksamkeit gegen malaria benzofuro[3,2-b]pyridin-4-ylamines e synthese und prüfung auf wirksamkeit gegen malaria benzothieno[3,2-b]pyridin-4-yl-amine e synthese und prüfung auf wirksamkeit gegen malaria thieno[3,2-c]chinolin-4-ylamine e synthese und prüfung auf wirksamkeit gegen malaria thieno[3,4-c]chinolin-4-ylamine e synthese und prüfung auf wirksamkeit gegen malaria naphthyridin-5-yl-arylamine e phenol-mannich-basen vom amodiaquin-, cycloquin-und pyronaridin-typ antimalarial mannoxanes: hybrid antimalarial drugs with outstanding oral activity profiles and a potential dual mechanism of action aromatic amino analogues of artemisinin: synthesis and in vivo antimalarial activity artemisinin derivatives bearing mannich base group: synthesis and antimalarial activity novel in vivo active anti-malarials based on a hydroxy-ethyl-amine scaffold modular synthesis and in vitro and in vivo antimalarial assessment of c-10 pyrrole mannich base derivatives of artemisinin mechanism-based inactivation of thioredoxin reductase from plasmodium falciparum by mannich bases. implication for cytotoxicity synthesis and biological evaluation of phenolic mannich bases of benzaldehyde and (thio)semicarbazone derivatives against the cysteine protease falcipain-2 and a chloroquine resistant strain of plasmodium falciparum design, synthesis and structureeactivity relationships of (1h-pyridin-4-ylidene)amines as potential antimalarials synthesis and in vitro activities of ferrocenic aminohydroxynaphthoquinones against toxoplasma gondii and plasmodium falciparum pershina, indole derivative having antiviral arbidol: a broad-spectrum antiviral compound that blocks viral fusion mechanism of inhibition of enveloped virus membrane fusion by the antiviral drug arbidol synthesis and in vitro anti-hepatitis b virus activities of some ethyl 6-bromo-5-hydroxy-1h-indole-3-carboxylates synthesis and in vitro anti-hepatitis b virus activity of some ethyl 5-hydroxy-4-substituted aminomethyl-2-sulfinylmethyl-1h-indole-3-carboxylates synthesis and in vitro anti-hepatitis b virus activities of some ethyl 5-hydroxy-1h-indole-3-carboxylates synthesis and in vitro-anti-hepatitis b virus activities of several ethyl 5-hydroxy-1h-indole-3-carboxylates synthesis and anti-hepatitis b virus evaluation of novel ethyl 6-hydroxyquinoline-3-carboxylates in vitro synthesis and in-vitro antihepatitis-b virus activity of 6h synthesis and in vitro anti-hepatitis b virus activity of 6h-[1]benzothiopyrano[4,3-b]quinolin-9-ols synthesis and in vitro anti-hepatitis b virus activity of 1h-benzimidazol-5-ol derivatives synthesis and biological evaluation of 1h-benzimidazol-5-ols as potent hbv inhibitors synthesis and in-vitro anti-hepatitis b virus activity of ethyl 6-bromo-8-hydroxyimidazo[1,2-a] pyridine-3-carboxylates activity of mannich bases of 7-hydroxycoumarin against flaviviridae novel structurally related compounds reactivate latent hiv-1 in a bcl-2-transduced primary cd4þ t cell model without inducing global t cell activation synthesis and primary antiviral activity evaluation of 3-hydrazono-5-nitro-2-indolinone derivatives design of potential reverse transcriptase inhibitor containing isatin nucleus using molecular modeling studies newer aminopyrimidinimino isatin analogues as non-nucleoside hiv-1 reverse transcriptase inhibitors for hiv and other opportunistic infections of aids: design, synthesis and biological evaluation n-methylisatin-beta-thiosemicarbazone derivative (sch 16) is an inhibitor of japanese encephalitis virus infection in vitro and in vivo condensed pentacyclic derivatives for use in the treatment of flaviviridae infections synthesis, antiviral and cytotoxicity studies of novel n-substituted indophenazine derivatives, indian synthesis of some mono-mannich bases and corresponding azine derivatives and evaluation of their anticonvulsant activity evaluation of anticonvulsant activities of bis(3-aryl-3-oxo-propyl)ethylamine hydrochlorides and 4-aryl-3-arylcarbonyl-1-ethyl-4-piperidinol hydrochlorides synthesis and evaluation of anticonvulsant activities of some bis mannich bases and corresponding piperidinols synthesis of some new hydroxypyranone derivatives and evaluation of their anticonvulsant activities synthesis of some novel mannich bases derived from allomaltol and evaluation of their anticonvulsant activities anticonvulsant and neurotoxicity evaluation of some novel kojic acids and allomaltol derivatives synthesis and anticonvulsant activity of new kojic acid derivatives synthesis of aminomethyl-substituted cyclic imide derivatives for evaluation as anticonvulsants synthesis and anticonvulsant activity of new n-mannich bases derived from 5-cyclopropyl-5-phenylhydantoins synthesis and anticonvulsant activity of new n-mannich bases derived from 5-cyclopropyl-5-phenyl-and 5-cyclopropyl-5-(4-chlorophenyl)-imidazolidine-2,4-diones synthesis and anticonvulsant activity of new n-1 0 synthesis and potential anticonvulsant activity of new n-3-substituted 5,5-cyclopropanespirohydantoins synthesis and pharmacological evaluation of novel 1 0 karolak-wojciechowska, design, synthesis, and anticonvulsant activity of new n-mannich bases derived from spirosuccinimides and spirohydantoins synthesis and anticonvulsant properties of new n-[(4-arylpiperazin-1-yl)-methyl] derivatives of 3-aryl pyrrolidine-2,5-dione and 2-aza-spiro synthesis and anticonvulsant activity of new n-[(4-arylpiperazin-1-yl)-alkyl] derivatives of 3-phenylpyrrolidine-2,5-dione synthesis, physicochemical and anticonvulsant properties of new n-[(4-aryl-1-piperazinyl) alkyl]-1-phenyl-2,5-pyrrolidinedione and n-[(4-aryl-1-piperazinyl)alkyl]-3-(3-methylphenyl)-2,5-pyrrolidinedione derivatives synthesis and anticonvulsant properties of new mannich bases derived from 3-aryl-pyrrolidine-2,5-diones synthesis and anticonvulsant activity of new n-mannich bases derived from 3-(2-fluorophenyl)-and 3-(2-bromophenyl)-pyrrolidine-2,5-diones. part ii design, synthesis and anticonvulsant properties of new n-mannich bases derived from 3-phenylpyrrolidine-2,5-diones duszy nska, synthesis, anticonvulsant activity and 5-ht 1a , 5-ht 2a receptor affinity of new n-[(4-arylpiperazin-1-yl)-alkyl] derivatives of 2-azaspiro synthesis and anticonvulsant properties of new mannich bases derived from 3,3-disubstituted pyrrolidine-2,5-diones. part iv synthesis and anticonvulsant properties of new n-mannich bases derived from 3,3-diphenyl-and 3-ethyl-3-methyl-pyrrolidine-2,5-diones. part iii synthesis and biological properties of new n-mannich bases derived from 3-methyl-3-phenyl-and 3,3-dimethyl-succinimides. part v anticonvulsant activity and 5-ht 1a /5-ht 7 receptors affinity of piperazine derivatives of synthesis of some newer derivatives of substituted quinazolinonyl-2-oxo/thiobarbituric acid as potent anticonvulsant agents synthesis and pharmacological evaluation of newer substituted benzoxazepine derivatives as potent anticonvulsant agents synthesis and evaluation of some new substituted benzothiazepine and benzoxazepine derivatives as anticonvulsant agents synthesis and anticonvulsant activity of various mannich and schiff bases of 1,5-benzodiazepines novel 2-(e)-substituted benzylidene-6-(n-substituted aminomethyl)cyclohexanones and cyclohexanols as analgesic and anti-inflammatory agents biochemical effects of some new mannich base from ortho-hydroxyaryl alkyl ketones on rats with chronic inflammation synthesis and pharmacological activity of n-[b-(para-substituted benzoyl)ethyl]isoleucine and -methionine synthesis and anti-inflammatory, analgesic, and antipyretic activities of n-[b-(p-substituted benzoyl)ethyl]amino acids anti-inflammatory activity of isobornylphenol derivatives synthesis and antiinflammatory activity of resveratrol analogs new 4,6-diacetylresorcinol mannich bases: synthesis and biological evaluation synthesis and biological evaluation of nitrogencontaining benzophenone analogues as tnf-a and il-6 inhibitors with antioxidant activity synthesis and biological evaluation of nitrogen-containing chalcones as possible anti-inflammatory and antioxidant agents synthesis and antiinflammatory activity of chalcones and related mannich bases inhibitory effects of mannich bases of heterocyclic chalcones on no production by activated raw 264.7 macrophages and superoxide anion generation and elastase release by activated human neutrophils synthesis of some new 3,4-dihydro-2h-1,3-benzoxazines under microwave irradiation in solvent-free conditions and their biological activity synthesis and antiinflammatory activity of coumarin derivatives anti-inflammatory mechanisms of isoflavone metabolites in lipopolysaccharide-stimulated microglial cells synthesis and no production inhibition of novel mannich base derivatives of irisolidone synthesis and in-silico studies of some diaryltriazole derivatives as potential cyclooxygenase inhibitors regioselective reaction: synthesis and pharmacological study of mannich bases containing ibuprofen moiety regioselective reaction: synthesis, characterization and pharmacological activity of some new mannich and schiff bases containing sydnone synthesis, characterization and pharmacological activity of 4-{[1-substituted aminomethyl-4-arylideneamino-5-sulfanyl-4,5-dihydro-1h-1,2,4-triazol-3-yl] methyl}-2h-1,4-benzothiazin-3(4h)-ones synthesis and anti-inflammatory activity of new polyheterocyclic schiff bases and mannich bases docking, synthesis, and pharmacological investigation of novel substituted thiazole derivatives as non-carboxylic, anti-inflammatory, and analgesic agents synthesis, analgesic and antiinflammatory properties of certain 5-/6-acyl-3-(4-substituted-1-piperazinylmethyl)-2-benzoxazolinones derivatives synthesis and evaluation of analgesic, anti-inflammatory and antimicrobial activities of 6-acyl-3-piperazinomethyl-2-benzoxazolinones some new mannich bases of 5-methyl-2-benzoxazolinones with analgesic and antiinflammatory activities analgesic and antiinflammatory activities of some new mannich bases of 5-nitro-2-benzoxazolinones synthesis and pharmacological evaluation of 1-(1-((substituted)methyl)-5-methyl-2-oxoindolin-3-ylidene)-4-(substituted pyridin-2-yl)thiosemicarbazide synthesis, analgesic, antiinflammatory and ulcerogenic properties of some novel n 0 -((1-(substitutedamino)methyl)-2-oxoindolin-3-ylidene)-4-(2-(methyl/phenyl)-4-oxoquinazolin-3(4h)-yl)benzohydrazide derivatives synthesis, pharmacological screening, quantum chemical and in vitro permeability studies of n-mannich bases of benzimidazoles through bovine cornea synthesis and biological evaluation of mannich bases of benzimidazole derivatives synthesis, antiinflammatory and ulcerogenicity studies of some substituted pyrimido[1,6-a]azepine derivatives potential antiinflammatory activity and ulcerogenicity study of some novel pyrimido synthesis and anti-inflammatory activity of certain piperazinylthienylpyridazine derivatives design and synthesis of 3-[3-(substituted phenyl)-4-piperidin-1-ylmethyl/-4-morpholin-4-ylmethyl-4,5-dihydro-isoxazol-5-yl]-1h-indoles as potent anti-inflammatory agents efficient synthesis of the first betulonic acideacetylene hybrids and their hepatoprotective and anti-inflammatory activity substituted 1 and 2-naphthol mannich bases synthesis and analgesic activity of novel derivatives of 1,2-substituted benzimidazoles synthesis and in vivo pharmacology of new derivatives of isothiazolo[5,4-b] pyridine of mannich base type synthesis, analgesic activity and computational study of new isothiazolopyridines of mannich base type thymol analogues with antioxidant and l-type calcium current inhibitory activity alzheimer's disease, with neuroprotective, cholinergic, antioxidant, and copper-complexing properties mannich bases of scutellarein as thrombin-inhibitors: design, synthesis, biological activity and solubility synthesis of antioxidants for prevention of age-related macular degeneration synthesis and antioxidant activity of novel mannich base of 1,3,4-oxadiazole derivatives possessing 1,4-benzodioxan design, synthesis, and in vitro antioxidant activity of 1,3,5-trisubstituted-2-pyrazolines derivatives synthesis and antioxidant activity of aminomethylated 6-methyluracil derivatives synthesis and antihypertensive effects of new methylthiomorpholinphenol derivatives antihypertensive and antiarrhythmic properties of a para-hydroxy[bis(ortho-morpholinylmethyl)] phenyl-1,4-dhp compound: comparison with other compounds of the same kind and relationship with logp values 1-and 2-substituted naphthalenes: a new class of potential hypotensive agents studies on the cardiovascular action of tpyb: an antihypertensive agent with antiplatelet activity synthesis, characterization and antihypertensive activity of pyridazinone derivatives synthesis and pharmacological activity of 2-and 3-(aminomethyl)imidazo [1,2-a]benzimidazoles new octahydroquinazoline derivatives: synthesis and hypotensive activity irreversible inactivation of trypanothione reductase by unsaturated mannich bases: a divinyl ketone as key intermediate unsaturated mannich bases active against multidrugresistant trypanosoma brucei brucei strains antileishmanial pyrazolopyridine derivatives: synthesis and structureeactivity relationship analysis mannich base derivatives of 1,3,4-oxadiazole: synthesis and screening against entamoeba histolytica in vitro antischistosomal evaluation of some newly synthesized praziquantel derivatives structureeactivity relationships of chalcone analogs as potential inhibitors of adpand collagen-induced platelet aggregation synthesis and pharmacological evaluation of peptide-mimetic protease-activated receptor-1 antagonists containing novel heterocyclic scaffolds the association of helicobacter pylori infection and nonsteroidal anti-inflammatory drugs in peptic ulcer disease synthesis and antiulcer activity study of 1,4-dihydropyridines and their mannich bases with sulfanilamide synthesis of 6-and 9-alkylaminomethyl furoflavones as gastroprotective agents submitted to the 65 th world health assembly synthesis and antidepressant-like profile of novel 1-aryl-3-[(4-benzyl)piperidine-1-yl]propane derivatives design, synthesis, computational and biological evaluation of new anxiolytics benzoxepin derivatives: design, synthesis, and pharmacological evaluation with sedativeehypnotic effect synthesis and hepatoprotector activity of water-soluble derivatives of aminoalkylphenols design, synthesis and preliminary biological evaluation of zatebradine analogues as potential blockers of the hyperpolarization-activated current synthesis and antiemetic activity of 1,2,3,9-tetrahydro-9-methyl-3-(4-substituted-piperazin-1-ylmethyl)-4h-carbazol-4-one derivatives synthesis of tropolone derivatives and evaluation of their in vitro neuroprotective activity bone selective protective effect of a novel bone-seeking estrogen on trabecular bone in ovariectomized rats a one step/one pot synthesis of n,nbis(phosphonomethyl)amino acids and their effects on adipogenic and osteogenic differentiation of human mesenchymal stem cells the mannich base nc1153 promotes long-term allograft survival and spares the recipient from multiple toxicities donepeziletacrine hybrid related derivatives as new dual binding site inhibitors of ache synthesis and acetylcholinesterase (ache) inhibitory activity of some n-substituted-5-chloro-2(3h)-benzoxazolone derivatives synthesis and biological evaluation of 1,3-dihydroxyxanthone mannich base derivatives as anticholinesterase agents synthesis and biological evaluation of novel 8-aminomethylated oroxylin a analogues as a-glucosidase inhibitors synthesis and evaluation of 5-(6-methoxynaphthalen-2-yl)-1-aryl-1-(4-(trifluoromethyl) phenylamino)pentan-3-ones as potential antidiabetic agents synthesis and antidiabetic performance of b-amino ketone containing nabumetone moiety synthesis of novel b-amino ketones containing a p-aminobenzoic acid moiety and evaluation of their antidiabetic activities exploring structureeactivity relationships of transition state analogues of human purine nucleoside phosphorylase synthesis of second-generation transition state analogues of human purine nucleoside phosphorylase synthesis of a transition state analogue inhibitor of purine nucleoside phosphorylase via the mannich reaction third-generation immucillins: syntheses and bioactivities of acyclic immucillin inhibitors of human purine nucleoside phosphorylase syntheses and bio-activities of the l-enantiomers of two potent transition state analogue inhibitors of purine nucleoside phosphorylases immucillins in custom catalytic-site cavities a bfluoroamine inhibitor of purine nucleoside phosphorylase azetidine based transition state analogue inhibitors of n-ribosyl hydrolases and phosphorylases design and synthesis of potent "sulfur-free" transition state analogue inhibitors of 5 0 -methylthioadenosine nucleosidase and 5 0 -methylthioadenosine phosphorylase augustyns, narylmethyl substituted iminoribitol derivatives as inhibitors of a purine specific nucleoside hydrolase potent transglutaminase inhibitors, aryl b-aminoethyl ketones potent transglutaminase inhibitors, dithio b-aminoethyl ketones synthesis and characterization of phenolic mannich bases and effects of these compounds on human carbonic anhydrase isozymes i and ii nitrogen-containing flavonoid analogues as cdk1/cyclin b inhibitors: synthesis, sar analysis, and biological activity hit identification of novel heparanase inhibitors by structure and ligand-based approaches discovery of inhibitors of burkholderia pseudomallei methionine aminopeptidase with antibacterial activity search for inhibitors of bacterial and human protein kinases among derivatives of diazepines[1,4] annelated with maleimide and indole cycles umbelliferone aminoalkyl derivatives, a new class of squalene-hopene cyclase inhibitors synthesis of new 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine derivatives with an incorporated thiazolidinone moiety and testing their possible serine protease and cercarial elastase inhibitory effects with a possible prospective to block penetration of schistosoma mansoni cercariae into the mice skin synthesis and biological activity of oxadiazole and triazolothiadiazole derivatives as tyrosinase inhibitors novel mannich bases, 5-arylimidazolidine-2,4-dione derivatives with dual 5-ht 1a receptor and serotonin transporter affinity pharmacophore based synthesis of 3-chloroquinoxaline-2-carboxamides as serotonin 3 (5-ht 3 ) receptor antagonist synthesis and biological evaluation of a novel structural type of serotonin 5-ht 3 receptor antagonists ]pyridine: an antagonist with high affinity and selectivity for the human dopamine d 4 receptor azaindole derivatives with high affinity for the dopamine d 4 receptor: synthesis, ligand binding studies and comparison of molecular electrostatic potential maps phenylpiperazinylmethylheterocycle derivatives: synthesis and dopamine receptor binding profiles synthesis of 5-[(4-phenylpiperazin-1-yl)methyl]pyrrolo [2,3-d]pyrimidine derivatives as potential dopamine d 4 receptor ligands design, synthesis and dopamine d4 receptor binding activities of new n-heteroaromatic 5/6-ring mannich bases discovery of highly potent and selective d4 ligands by interactive sar study synthesis and evaluation of ligands for d 2 -like receptors: the role of common pharmacophoric groups discovery of small molecule inhibitors of the interaction of the thyroid hormone receptor with transcriptional coregulators inhibitors of the interaction of a thyroid hormone receptor and coactivators: preliminary structureeactivity relationships structural insight into the mode of action of a direct inhibitor of coregulator binding to the thyroid hormone receptor improvement of pharmacological properties of irreversible thyroid receptor coactivator binding inhibitors discovery and biological characterization of a novel series of androgen receptor modulators aromatic b-amino-ketone derivatives as novel selective non-steroidal progesterone receptor antagonists synthesis and biological evaluation of n 1 ,n 2 -bis-[4-(t-amino)-2-butynyl]phthalamides as oxotremorine and acetylcholine antagonists synthesis and structureactivity relationships of 1-aralkyl-4-benzylpiperidine and 1-aralkyl-4-benzylpiperazine derivatives as potent s ligands indole-and benzothiophene-based histamine h 3 antagonists new 1,2,3,9-tetrahydro-4h-carbazol-4-one derivatives: analogues of heat as ligands for the a 1 -adrenergic receptor subtypes pyrazolone methylamino piperidine derivatives as novel ccr3 antagonists synthesis of new 4-heteroaryl-2-phenylquinolines and their pharmacological activity as nk-2/nk-3 receptor ligands the author declares that there is no conflict of interest. key: cord-020010-q58x6xb0 authors: nan title: 19th icar abstracts: date: 2006-03-13 journal: antiviral res doi: 10.1016/j.antiviral.2006.02.001 sha: doc_id: 20010 cord_uid: q58x6xb0 nan the society was organized in 1987 as a non-profit scientific organization for the purpose of advancing and disseminating knowledge in all areas of antiviral research. to achieve this objective, the society organizes an annual meeting. the society is now in its 20 th year of existence, and has about 600 members representing 30 countries. for membership application forms or further information, please contact dr. amy patick, secretary, isar; pfizer global r&d, department of virology, 10777 science center drive, san diego, ca 92121; phone +1 858 622 3117; fax +1 858 678 8182; e-mail amy.patick@pfizer.com. membership application forms will also be available at the conference registration desk, or from our website www.isar-icar.com. enzymes of the pol gene of hiv have been identified as important viral targets for the discovery anti-hiv therapeutic agents. while the viral targets, hiv reverse transcriptase and hiv protease, have been successfully investigated for the development of clinically useful therapeutic agents, research efforts on drug discovery on the third enzyme of the pol gene, hiv integrase, have not resulted in a single fda-approved drug. nevertheless, as integrase is essential for hiv replication, it remains an attractive target for the discovery of new anti-hiv agents. in this presentation, we report the discovery of a conceptually new beta-diketo acid, constructed on a nucleobase scaffold, that is a potent inhibitor of both the 3 -processing and strand transfer steps of recombinant hiv integrase. this inhibitor and the positive control compound, azt, were tested in a pbmc cellbased, microtiter anti-hiv assay against the clinical isolate, hiv-1teki (nsi phenotype) and hiv-1nl4-3 (si phenotype), and in a magi-x4 assay against hiv-1nl4-3 with hela-cd4-ltr-beta-gal cells. our integrase inhibitor was found to have highly potent in vitro anti-hiv activity and efficacy. the discovery of this remarkably active molecule, representative of a unique set of diketo acids bearing nucleobase scaffolds, has uncovered a new chapter in the chemistry and biology of integrase inhibitors and their potential therapeutic applications. berta bosch 1 , imma clotet-codina 1 , julia blanco 1 , eduard pauls 1 , gemma coma 1 , samandhy cedeño 1 , francesc mitjans 2 , anuska llano 1 , margarita bofill 1 , bonaventura clotet 1 , jaume piulats 2 , jose este 1 1 retrovirology laboratory, fundacio irsicaixa, badalona, spain; 2 laboratorio de bioinvestigación, merck farma y química, barcelona, spain macrophages are key cells for hiv infection and spreading inside the organism. macrophages cultured in vitro can be successfully infected after differentiation with cytokines such as macrophage colony stimulating factor (m-csf). in the monocyte to macrophage differentiation process with m-csf, av-integrins are upregulated concomitantly to the capacity of hiv to generate a productive virus infection. in the present study we show that an anti-av antibody, 17e6, inhibited hiv-1 infection of primary macrophages. the effect of 17e6 on r5 or x4 hiv-1 replication in acutely infected macrophages was dose-dependent, with a 50% effective concentration (ec50) of 17 ± 2 g/ml in the absence of cytotoxicity. similarly, a monoclonal antibody targeting the avb6 integrin (14d9.f8) also inhibited hiv-1 infection in this cell type. 17e6 reduced the detection of hiv-1 bal proviral dna in acutely infected macrophages but was completely ineffective against hiv-1 bal production in chronically infected macrophages, suggesting that 17e6 inhibited hiv infection at an early stage of the virus cycle. finally, a small molecular weight antagonist of the avb6 integrin reduced hiv replication at subtoxic concentrations. therefore, our results suggest that av-containing integrins could play a role in hiv replication in macrophages and indicate that small molecular weight compounds may be developed to interfere with hiv replication in macrophages through the interaction with av integrins. andrew vaillant 1 , hong lu 2 , shuwen liu 2 , carol lackman-smith 3 , roger ptak 3 , jean-marc juteau 1 , shibo jiang 2 1 replicor inc., laval, que., canada; 2 f. lindsay kimball research institute, new york blood center, new york, ny, usa; 3 southern research institute, frederick, md, usa the sequence independent antiviral activity of phosphorothioate oligonucleotides in inhibiting hiv-1 by blocking interactions between the v3 loop and cd4 has been previously described. this activity was attributed to their polyanionic activity. here we show that ps-ons (and their fully 2 -o-methylated derivatives) are also potent inhibitors of hiv-1-mediated membrane fusion and hiv-1 replication in a sequence-independent, sizedependent (optimal size ∼50-60 bases) and phosphorothioation dependent manner (independent of stabilization). ps-ons interact with the heptad repeat regions of gp41 and the hiv-1 fusion inhibitory activity of ps-ons is closely correlated with their ability to bind to these heptad repeats and block gp41 six-helix bundle formation, a critical step during the process of hiv-1 fusion with the target cell. the requirement for ps-on interaction was also found to be dependent on phosphorothioation, suggesting that the v3 loop/ps-on interaction may also have a hydrophobic component. the increased hydrophobicity of longer (≥40 base) ps-ons may contribute to their inhibitory activity against hiv-1 fusion and entry because these longer ps-ons have a greater hydrophobicity and are more potent in blocking the hydrophobic interactions involved in the gp41 sixhelix bundle formation than shorter ps-ons (<30 bases). this novel antiviral mechanism of action of long ps-ons has important implications for therapy against infection by hiv-1 and other enveloped viruses with type i fusion proteins. chris meier 1 , soenke jessel 1 , bastian reichardt 1 , olaf ludek 1 , jan balzarini 2 1 university of hamburg, institute of organic chemistry, hamburg, germany; 2 rega institute for medical research, katholieke universiteit leuven, leuven, belgium carbocyclic nucleoside analogues like abacavir showed very interesting antiviral properties. therefore, we are interested in a convenient stereoselective access to this class of compounds as potential antiviral agents. by using a new convergent synthetic strategy, starting from a chiral cyclopentenol, enantiomerically pure carbocyclic thymidine (carba-dt) was obtained as a key intermediate for further variations at the 3 -position. this pathway allows an entry to d-and l-configurated nucleoside analogues. however, using this approach a mixture of side products avoids the formation of the product in very high yields. however, we will present that the side products can be recovered by a stereoselective hydroboration leading to one intermediate only that can be use as well for the synthesis of carbocyclic nucleosides. the condensation of the carbocyclic moiety and different pyrimidine and purine nucleobase was achieved by a mitsunobu reaction. various analogues have been prepared via this strategy, e.g. d-and l-carba-bvdu, nucleoside analogues known to be antivirally active against hsv-1. additionally, carbocyclic ␣nucleosides and carbocyclic iso-nucleosides are accessible by this reaction sequence. all new nucleoside analogues were tested for their antiviral activity. particularly carba-dt was found to be a potent anti-hiv active derivative showing no toxicity. however, it can not be excluded that a non-activity of a compound is related to a missing phosphorylation to the monophosphate. in order to prove that, all nucleosides were converted into their cyclosal-phosphate trimesters and transferred into the nucleotides. detailed chemistry, enzymatic and antiviral activity data will be presented. in some cases the nucleotide releasing system showed improved antiviral activity as compared to the parent nucleoside. michela pollicita 1 , candace pert 2 , maria-teresa polianova 2 , alessandro ranazzi 1 , michael ruff 2 , carlo-federico perno 1 , stefano aquaro 1 1 university of rome tor vergata, italy; 2 georgetown university, washington, dc, usa monocytes/macrophages (m/m) are a strategic reservoir of hiv-1 commonly infected by ccr5-using (r5) strains of hiv-1. ccr5 is an attractive target for inhibition of ccr5 mediated hiv-1 entry. thus, ccr5 antagonists are expected to be a power-ful new class of receptor-based therapeutic agents against hiv-1 infection. d-ala-peptide t-amide (dapta) is an octapeptide derived from the gp120 v2 region of hiv-1, able to bind ccr5. dapta acts as selective viral entry inhibitor, displacing the binding of gp120 with ccr5. dapta anti-hiv-1 activity was evaluated in m/m infected with two different hiv-1 r5 strains, bal and 81a, in presence of several doses of the compound. dapta inhibited hiv-1 replication in m/m (>80% compared to control), measured by the p24 gag ag released in the cell culture supernatants, at concentration of 10-3 nm. pcr analysis of integrated hiv-1 proviral dna on cultured m/m proved that dapta is able to block hiv entry and so, to prevent hiv infection in m/m. moreover, the capability of different hiv-1 r5 strains produced and released by infected m/m in affecting neuronal homeostasis was assessed in a neuroblastoma cell line, sk-n-sh, expressing ccr5. in sk-n-sh were evaluated cell morphology, propidium iodide binding and fluorescenceactivated cell sorting (facs) analysis. dapta, at concentration of 10-3 and 10-4 nm, strongly inhibited apoptosis in sk-n-sh of 58 and 56%, respectively, compared to control. unexpectedly, tak-779 (a nonpeptidic ccr5 antagonist with potent anti-hiv-1 activity) inhibited apoptosis only of 30% compared to control. our results suggest that the development of new anti-hiv-1 compounds, such as dapta, could be important in synergistic combination with other antiretroviral treatments in prevent both central nervous system hiv-infection and the consequent neural damage. the mechanisms of dapta inhibition may include both suppression of hiv-1 r5 strains in the brain as direct inhibition of hiv-1 replication in m/m and gp120 related damage by ccr5 binding. pradimicin a (prm-a) is an antifungal non-peptidic benzonaphtacenequinone antibiotic that specifically inhibits human immunodeficiency virus (hiv) in cell culture. it markedly suppresses a variety of different hiv-1 clades in pbmcs, in primary macrophages and several hiv-2 and siv strains in laboratory cell lines (range of 50% effective concentrations: 0.69-11 g/ml; 50% cytostatic concentration: >50 g/ml). prm-a also inhibits syncytium formation between persistently hiv-1-infected hut-78 cells and uninfected sup t1 cells. prm-a behaves as an artificial lectin that selectively binds mannose-containing glycans. consequently, biacore experiments revealed that it binds to gp120 of hiv-1/mn in the presence of ca 2+ . prm-a is endowed with a high genetic barrier with regard to drug resistance development against hiv-1. a variety of multiple mutations at n-glycosylation sites in hiv-1 gp120 are required before the virus looses marked sensitivity to the drug. there is no clustered pattern of hiv-1 gp120 glycan deletions that occur under prm-a drug pressure. the resistance spectrum and mode of action is unique among any of the existing anti-hiv drugs and warrant further (pre)clinical investigations. acknowledgement: this research was supported by the flemish "fonds voor wetenschappelijk onderzoek," the centers of excellence of the k.u. leuven (no. ef/05/15), and the european commission (empro). jan muench 1 , ludger ständker 2 , knut adermann 2 , axel schulz 2 , michael schindler 2 , raghavan chinnadurai 2 , wolf-georg forssmann 2 , frank kirchhoff 2 1 department of virology university of ulm, albert-einstein allee 11, 89081 ulm, germany; 2 ipf pharmaceuticals gmbh, feodor-lynen-strasse 31, 30625 hannover, germany a variety of components in human blood might influence hiv-1 replication in infected individuals. peptide libraries derived from hemofiltrate (hf), an aqueous blood solution, contain essentially all circulating blood peptides with a molecular mass below 30 kda, including chemokines, defensins, and cytokines. to identify the most potent natural occurring factors inhibiting hiv-1 replication, we screened a hf-derived peptide library for antiviral activities. the most active fraction contained a 20-residue peptide corresponding to a c-terminal fragment of ␣1-antitrypsin (␣1-at), a highly abundant serine proteinase inhibitor. further analysis of the corresponding chemically synthesized peptide, termed virus inhibitory peptide (virip), demonstrated that it inhibits infection by all hiv-1 variants tested, independently of their subtype and coreceptor usage. notably, virip also blocked multi-resistant hiv-1 variants and primary isolates. virip specifically inhibited hiv-1 env function, and did not affect infection by virions containing hiv-2, siv, mlv, hcv, ebola or vsv env proteins. the antiviral activity proved to be highly specific for the 20-residue virip sequence since structurally closely related peptides were inactive. we found that virip inhibits hemolysis of erythrocytes induced by the hiv-1 gp41 fusion-peptide (fp). nmr spectroscopy confirmed that virip interacts directly with synthetic gp41 fp. our observations are evidence that a naturally occurring human substance inhibits hiv-1 infection by a new mode of action, i.e. binding of the highly conserved fp. furthermore, we performed a structure-activity-relation study with more than 350 virip analogs and found that specific amino acid changes enhanced the antiviral potency of virip by up to two orders of magnitude. experiments in cell culture and animal models further demonstrated that virip exerted no cytotoxic effects. thus, virip derivatives might become a new class of hiv-1 entry inhibitors. stefano aquaro 1 , valentina svicher 1 , roberta d'arrigo 2 , ubaldo visco-comandini 2 , andrea antinori 2 , mario santoro 1 , giovanni di perri 3 , sergio lo caputo 4 , pasquale narciso 2 , carlo-federico perno 1,2 1 university of rome tor vergata, italy; 2 inmi l. spallanzani, italy; 3 university of turin, italy; 4 sm annunziata hospital, florence, italy to investigate gp41-variability and correlation with viroimmunological parameters in 54 hiv-infected patients (pts) receiving t20 added as a single active drug to a failing regimen. two hundred and ten hiv-gp41 sequences and clinical follow-up from 54 t20-treated patients were analyzed from baseline up to 48 weeks (weeks) of treatment. the association of mutations with viremia (vl)/cd4 count (c/ul) was assessed by mann-whitney test. the addition of t20 to the failing antiretroviral regimen induced at 4 weeks a significant vl decrease from 5.1 log (stable in the last 12 weeks prior t20) to 4.3 log (p = .0002) and a significant cd4 increase from 48 c/ul (decreasing in the last 12 weeks prior t20) to 106 c/ul (p = .008). while vl rebounded to 4.7-5 log at 12-48 weeks, respectively, cd4 increased to 129 c/ul at 48 weeks. t20 resistance mutations, absent at bl, occurred shortly after treatment and usually alone. v38a was the most common sign of t20 failure (27.8% of pts). the viroimmunological outcome of t20-treated pts varied according to gp41-mutations. v38a/e (38.5% of pts) was associated with a cd4 increase from bl (48 c/ul) of 4.5-fold (142 c/ul) at 24 weeks and 6.0-fold (196 c/ul) at 36 weeks (p = .004 and .02 compared without v38a/e, respectively). no significant correlation with vl was observed (from 4.9 log at bl to 4.4-4.8 at 24-36 weeks). by contrast, q40h + l45m (11.1% of pts) was associated with cd4 loss from 71 c/ul at bl to 26 c/ul at 36 weeks (p = .02), without significant changes in vl (from 5 log at bl to 5 log at 36 weeks). mutation n126k (observed in 6 pts, but never found at bl) abrogates the 4th gp41-glycosylation site and correlated with 1.7-fold cd4 increase at 24 weeks. conformational changes induced by v38a/e in the highly conserved giv motif of gp41-hr1, are tightly related with a loss of hiv-induced damage of immune system. this facilitates cd4-recovery through mechanisms that can be virus-(loss of fusion efficiency) and immune-mediated (exposure of new epitopes) not applicable to protease/rt-inhibitors, and thus important for innovative therapeutic strategies. the spread of highly pathogenic h5n1 influenza viruses in humans in asia, with high mortality rates among infected individuals is a major public health concern. in the absence of a vaccine antigenically matching the pandemic virus, antiviral drugs can play an important role. in the present study we reported the antiviral activity of neuraminidase inhibitor oseltamivir against lethal h5n1 influenza virus infection in ferrets, an appropriate animal model that closely resembles clinical signs of human influenza. inoculation of young adult ferrets with a viral dose as low as 10 2 eid 50 of a/vietnam/1203/04 (h5n1) influenza virus caused high fever (39.8-41.8 • c), weight loss (25.4% of initial), anorexia, extreme lethargy and death of animals on days 7-10 post-virus inoculation (p.i.). oral administration of oseltamivir at a dose of 5 mg/kg/day for 5 days twice daily initiated 4 h p.i. inhibited the febrile response, reduced weight changes (14.6% of initial) and, most importantly, completely protected ferrets from lethal h5n1 infection. in the treatment groups, virus replication in the upper respiratory tract of ferrets was prevented, whereas untreated animals shed virus at titers of 2.8-6.5 log 10 eid 50 /ml on days 3, 5 and 7 p.i. systemic spread of the h5n1 virus was observed in untreated ferrets: virus was detected in multiple internal organs, including the brain. treatment with oseltamivir resulted in complete inhibition of virus replication in the lungs and small intestine on day 5 p.i. in the brains of treated animals virus was detected in one of the two animals tested with >100-fold reduction of titer. sequence analysis showed no amino acid substitutions at conserved residues in na or ha1 subunit in viruses isolated from ferret's internal organs after treatment. these results suggest that oseltamivir earlier treatment can prevent h5n1 mortality in ferrets, however, further studies investigating optimal doses and treatment durations required to achieve protection against infection with highly pathogenic influenza viruses are much needed. natalia ilyushina, erich hoffmann, rachelle salomon, robert webster, elena govorkova st. jude children's research hospital, memphis, tn 38105, usa in the present study we tested in the mouse model the hypothesis that combination chemotherapy with drugs targeting dif-ferent virus proteins may lead to more potent and beneficial effects. we applied plasmid-based reverse genetics technique to generate two recombinant a/vietnam/1203/04-like (h5n1) viruses. one virus possessed asparagine at position 31 of the m2 protein that was found in the naturally circulating virus (rgvn-1203) and confers resistance to amantadine. the other recombinant virus possessed serine at that position and was sensitive to amantadine (rgvn-1203sens) . balb/c mice were administered oseltamivir (1 or 10 mg/kg/day) and amantadine (1.5 or 15 mg/kg/day) twice daily for 5 days by oral gavage; the first doses were given 24 h before inoculation with 10 mld50 of h5n1 virus. combination treatment with 10 mg/kg/day oseltamivir and 15 mg/kg/day amantadine was given on the same schedule. single-drug oseltamivir produced a dose-dependent antiviral effect against both recombinant h5n1 viruses (p < 0.01). treatment with oseltamivir at dosage of 10 mg/kg/day significantly inhibited virus replication in the lungs, brain, spleen, and blood of mice at days 3, 6, and 9 after inoculation (p < 0.05), but resulted in low survival rate (20%). single-drug amantadine showed dose-dependent effect only against rgvn-1203sens strain. notably, risk of death for mice that received 15 mg/kg/day of amantadine or 10 mg/kg/day of oseltamivir was similar (p < 0.05). in contrast, prophylactic treatment of mice with combinations of oseltamivir and amantadine completely inhibited virus replication in the animals infected with rgvn-1203sens (p < 0.05) compared to singledrug usage and protected 90% of animals. importantly combination chemotherapy completely protected h5n1 virus spread to the brain of the mice: virus was not detected in brain of treated animals on days 3, 6, and 9 after inoculation and neurological symptoms were not observed. our results suggest that combination chemotherapy provides an advantage over single-agent treatment. this strategy could be an option for the control of influenza virus infection, and combinations with other novel drugs should be explored. françois jean 1 , reid asbury 2 , meera raj 1 , david lawrence 3 , martin petric 3 1 the university of british columbia, vancouver, bc, canada v6t 1z3; 2 ge healthcare bio-sciences, piscataway, nj 08855, usa; 3 british columbia center for disease control, vancouver, bc, canada v5z 4r4 in late 2002, severe acute respiratory syndrome (sars) became the first new severe and easily transmissible human disease to emerge in the 21st century. although it abated after six months, sars serves as a modern paradigm for human emerging infections with 772 deaths reported from 29 countries. the causative agent was found to be a new sars-associated coronavirus (sars-cov) . while the sequence of sars-cov genome was first reported by the bc genome sciences center, the full set of viral and cellular proteins that compose the sars-cov virion remains unknown. to approach this problem, we have utilized two-dimensional gel electrophoresis and liquid chromatography-tandem ms (lc-ms/ms) to identify the viral and cellular proteins in purified sars-cov virions obtained from human infected cells [huh7: human liver] and primate (veroe6: monkey kidney) infected cells. interestingly, analysis of the proteins from purified sars-cov preparations has revealed that the enveloped virions contain not only the predicted viral structural proteins (e.g. spike glycoprotein, nucleocapsid protein, and membrane glycoprotein) but also an important number of differentially incorporated host cellular proteins into or onto the newly formed viruses. we have unambiguously identified over 50 host cellular proteins in sars-cov virions by lc-ms/ms. these proteins include members of the annexin superfamily, cytoskeletal proteins, chaperones, vesicular transport proteins, uracyl-dna glycosylases, and aldehyde oxidoreductases. this study provides the first comprehensive and comparative analysis of the viral and cellular proteins that compose infectious particles of sars-cov obtained from human and primate infected cells. the functions of these newly identified hostspecific proteins are currently being investigated using rna interfering systems; their contributions to structure, viral productive replication, and pathogenicity will be discussed. acknowledgement: supported by an early career ubc operating grant (f. jean) and cihr (m. petric) . dale barnard 1 , craig day 1 , robert montgomery 1 , kevin bailey 1 , matt heiner 1 , larry lauridsen 1 , robert sidwell 1 , kurt berg 2 1 institute for antiviral research, utah state university, logan, ut, usa; 2 panum inst., immi, the ifn-lab, copenhagen, denmark severe acute respiratory syndrome (sars) is a life-threatening respiratory illness caused by sars-cov. there are no approved therapies for sars. some drugs inhibit sars-cov replication in vitro including human interferons and selected antiinflammatory agents (chihrin and loufty, 2005. 3, 251-262) . interferons are very promising because of their potent in vitro inhibition of sars-cov. although anti-inflammatory agents are not very active in vitro, it is thought that they might be efficacious in reducing any deleterious inflammatory response associated with virus infections such as sars infections in humans. for example, troxerutin, a flavenoid with anti-inflammatory properties, is in clinical trials for treating rhinovirus (rv) infections, ameliorating rv-induced inflammation (turner et al., 2004. apmis 112, 605-611) . therefore, troxerutin was tested for inhibition of sars-cov replication in the lungs of infected mice using a mix of four hydroxyethylrutosides that included troxuretin. in addition, mouse interferon-alpha, used as a model compound for human interferon-alpha, was evaluated for inhi-bition of virus lung titers. both mouse interferon-alpha administered i.p. daily beginning 12 h pre virus exposure at doses of 100,000 and 10,000 iu and the hydroxyethylrutoside mix (100 and 10 mg/kg) administered i.p using the same schedule reduced virus replication in the lungs of mice to below detectable limits. when a hydroxyethylrutoside mix was given to mice in the drinking water at 1.32 mg/ml (likely equivalent to an i.p. dose of 100 mg/kg, assuming that the mice drank freely), virus lung replication was also completely inhibited. all treatments appeared to be well tolerated, since all groups of mice gained weight. we also report on the efficacy of various combinations of two doses of these drugs administered i.p., using the same dosing regimen as described. these data support the supposition that interferon might be a useful therapy for treating human sars infections and that hydroxyethylrutosides should be investigated further as a potential therapy. acknowledgement: supported by contract no. n01-ai-15435 from the virology branch, niaid, nih. treatment options for human respiratory syncytial virus (rsv) are limited. an effective vaccine is not yet available. neutralizing polyclonal antibody (respigam tm , medimmune) and a humanized monoclonal antibody (synagis tm , medimmune), are licensed for prophylactic use. ribavirin is the only approved antiviral against rsv, but its efficacy is controversial and its use is limited to treatment of high-risk patients. there is a clear need for new anti-rsv therapeutics with improved efficacy and ease-of-use. many early efforts to identify anti-rsv compounds focused on blocking the process of fusion. we have developed a cell-based screening platform to identify antivirals that inhibit rsv transcription and replication. the assay does not require infection with wild-type virus. it is based on an rsv subgenomic replication system in baby hamster kidney (bhk-21) cells that express the essential viral replication proteins (n, p, l and m2-1). the readout is expression of the reporter gene lacz from a subgenomic rna. screening of the apath small molecule library yielded 596 compounds (hit rate = 0.75%) with ec50 values ≤10 m and with selectivity index (si) values ≥10. seventy-two compounds demonstrated antiviral activity against wild-type rsv (strain a2) in a cytopathic effects inhibition assay (ec50 < 10 m; si > 10). these anti-rsv compounds represent nine different chemical classes. two compounds, a 4-aminoquinoline (ec50 = 0.25 m) and a thienopyrimidine (ec50 = 0.82 m), were shown to have desirable pharmacokinetic profiles and were chosen for efficacy testing in the cotton-tail rat model of infection. sar studies to identify the pharmacophore of the compounds have been initiated. preliminary studies to characterize the mechanism-ofaction in virological assays will be discussed. acknowledgement: supported by nih r44 ai047552-02. we have previously reported bicyclic furano pyrimidine nucleoside analogues (bcnas) as exquisitely potent and selective inhibitors of varicella zoster virus (vzv) , with subnanomolar activity for p-alkylphenyl substituted analogues such as lead compound cf1743(cf-1743) (1) . these compounds have entered preclinical development with fermavir pharmaceuticals. we now report the first chromatography-free synthesis of these agents, their scale up to multi-gramme amounts, and their pre-clinical characterisation. in addition, we were keen to address potential solubility and bioavailability issues of these highly lipophilic agents by the synthesis of more polar analogues in two categories; side-chain ethers (2) as new analogues in their own right, and 5 -phosphates (3) as potential more soluble prodrugs. we report data on both of these new families at this meeting. finally, we note the application of our phosphoramidate pro-tide approach to this family, with a series of bcna protides (4) designed as intracellular phosphate delivery forms to bypass the essential vzv thymidine kinase-mediated first phosphorylation step. graciela andrei 1 , joos van den oord 2 , pierre fiten 1 , ghislain opdenakker 1 , erik de clercq 1 , robert snoeck 1 1 rega institute for medical research, katholieke universiteit leuven, leuven, belgium; 2 pathology department, u.z. leuven, leuven, belgium varicella (chickenpox) , the primary infection caused by vzv, is characterized by viremia and skin lesions. reactivation of the latent virus results in skin lesions characteristic of herpes zoster (shingles). as keratinocytes are one of the main target cells for productive infection in vivo for vzv, human epithelial cells represent a relevant model for the study of vzv pathogenesis and evaluation of antiviral compounds. organotypic epithelial raft cultures permit full differentiation of keratinocytes via culturing of the cells on collagen matrix at the air-liquid interface. we have previously shown that the susceptibility of cultures to infection with vzv depends on the stage of differentiation of the rafts. we have now quantified the activity of reference anti-vzv compounds by measuring viral dna load by realtime pcr. quantitative pcr for vzv dna was performed by using specific primers and a mgb-probe for the orf29 gene (single-stranded dna binding protein) by the taqman method. two series of raft cultures were infected with the wild-type oka strain after 4 days of differentiation and treated with serial dilutions of the test compounds. at 12 days post-differentiation one series of the cultures was processed for histology and the other one for viral dna quantification. acyclovir (acv), penciclovir (pcv) and brivudin (bvdu) at 4 and 0.4 g/ml, foscarnet (pfa) at 40 g/ml and cidofovir (cdv) at 4, 0.4 and 0.04 g/ml inhibited viral dna content by more than 95%. these results were in agreement with histological examination of the rafts, no cytopathic effect being observed at these concentrations. as expected, only cdv and pfa inhibited the replication of the thymidine-kinase deficient (tk-) 07-1 strain. a correlation between the degree of protection as determined by histological examination and viral quantification could also be demonstrated for cdv and pfa against the tk-07-1 strain. since no animal model is available for the in vivo evaluation of antiviral agents against vzv, the organotypic cultures may be considered as a valuable ex vivo model to evaluate the efficacy of new anti-vzv antivirals. jae-seon hwang 1 , oliver kregler 1 , john c. drach 2,3 , leroy b. townsend 3 , elke bogner 1 1 institut für klinische und molekulare virologie, erlangen, germany; 2 department of biologic and materials sciences, school of dentistry; 3 interdepartmental graduate program in medicinal chemistry, college of pharmacy, university of michigan, ann arbor, mi, usa dna packaging is the key step in viral maturation and involves binding and cleavage of viral dna containing specific dnapackaging motifs. this process is mediated by a group of specific enzymes called terminases. we have previously demonstrated that the hcmv terminase is composed of two subunits, the large one encoding pul56 and the small pul89, where each protein has a different function. while the large subunit mediates sequence specific dna binding and atp hydrolysis, pul89 is only required for duplex nicking. inhibitors targeting pul56 and/or pul89 are attractive alternatives as hcmv antivirals since mammalian cell dna replication does not involve cleavage of concatameric dna. we now have screened several members of the benzimidazole ribonucleoside class of replication inhibitors in order to determine if a compound has the capacity to block the atpase activity of the large terminase subunit pul56. analysis by bioluminometric atpase activity assays identified bdcrb and one more compound [2-bromo-4,5,6-trichloro-1-(2,3,5-tri-o-acetyl-␤-dribofuranosyl)benzimidazole (btcrb)] with inhibitory effects. although only btcrb and bdcrb were inhibitors of the atpase activity, two other compounds, dbdcrb and cl4rb, inhibited virus replication in a plaque-reduction assay, thus indicating that those have a different mode of action. in addition, by electron microscopy of thin sections we observed that in the presence of btcrb only b-capsids and dense bodies were formed. furthermore, spherical capsids accumulated in the perinuclear cisternae indicating a block in nuclear egress thereby providing additional evidence that closely-related benzimidazole d-ribonucleosides may have differences in their antiviral modes of action. human cytomegalovirus (hcmv) is the cause of significant morbidity and mortality in a variety of immunocompromised patients. currently available anti-hcmv drugs interfere with dna replication; however, these drugs are highly toxic, pre-cluding their long-term use in humans. interrupting hcmv viral entry is largely unexplored as an antiviral drug development strategy and is potentially an ideal and tractable goal. hcmv is believed to rely upon formation of ␣-helical coiled coils in the viral glycoproteins gb and gh to promote virus-host membrane fusion; peptides encompassing heptad repeat sequences in these two proteins inhibit viral infection. we have explored nonnatural oligomeric molecules ("foldamers") that are designed to mimic elements of the putative ␣-helical segment of gb. this effort has led to the discovery of oligomers of ␤-amino acids ("␤-peptides") that block hcmv infection. the ␤-peptide scaffold offers several advantages for the design of protein-protein interaction inhibitors, as ␤-peptides are amenable to modular synthesis, resist proteolytic degradation, and can display large and tailored molecular surfaces. the most potent ␤-peptide inhibitor blocks hcmv infection with a micromolar ic 50 in a cell-based assay. these compounds show specificity for hcmv relative to closely related viruses. mechanistic studies suggest that these inhibitors interfere with membrane fusion between hcmv particles and host cells. current efforts are focused on understanding in greater detail the origin of the observed biological activity, exploring other foldamer scaffolds as bases for inhibitor design, and developing specific fusion inhibitors for other herpesviruses. previous reports have indicated that herpes simplex virus (hsv) activates nuclear factor-kappab (nf-kb) during productive infections. nonsteroidal anti-inflammatory drugs (nsaids) have significant inhibitory effects on nf-kb. therefore, two nsaids, indomethacin and aspirin, were assayed for antiherpetic effects and utilized as tools to further study the role of nf-kb in hsv-1 infection. we report that indomethacin and aspirin inhibited hsv-1 replication at non-cytotoxic doses. in vero cells, 500 um indomethacin and 20 mm aspirin reduced hsv-1 titers 99.999 and 99.5%, respectively. electromobility shift assays revealed that hsv-1 activation of nf-kb is inhibited by the nsaids at doses that coincide with reduction of hsv-1 titers. to investigate a pathway for nf-kb inactivation, protein levels of ikb-alpha, a cytoplasmic nf-kb inhibitor, were examined. ikb-alpha protein was present in uninfected samples, but decreased over time in all hsv samples, regardless of chemical treatment, suggesting localization of nf-kb to the nucleus. immunohistochemistry studies verified that p65, a component of the dimeric nf-kb complex, translocated to the nucleus of hsv-1 infected cells in the presence or absence of the nsaids. finally, direct effects on viral gene activity were assayed by real-time rt-pcr analysis. indomethacin and aspirin reduced mrna for icp4, an essential hsv immediate-early gene, 2.9and 2.5-fold, respectively, resulting in significant decreases of icp4 protein. but transcriptional analysis revealed that synthesis of mrna for thymidine kinase, an hsv early gene, was unaffected by chemical treatment. however, mrna for glycoprotein c, an hsv late gene was undetectable in indomethacin and aspirin treated samples. cumulatively, these data indicate that: (i) indomethacin and aspirin block hsv-1 replication and (ii) the in vitro anti-herpetic effects of nsaids may reside in their ability to block nf-kb activity within the nucleus, impairing activation of essentials hsv genes. increasing species-specificity constraints preclude study of human cytomegalovirus (hcmv) in animals, necessitating the use of rodent cmvs to model human disease. however, the susceptibility of animal cmvs to clinically useful antivirals is unpredictable. for example, the guinea pig cmv (gpcmv), a uniquely valuable virus for modeling congenital cmv infection, is highly resistant to ganciclovir (gcv) at medically relevant doses. we used a molecular virological approach to test the hypothesis that gcv susceptibility could be conferred on gpcmv by insertion of the human ul97 phosphotransferase gene into the gpcmv genome. the gpcmv genome, cloned as a bacterial artificial chromosome in e. coli, was modified by site-specific recombination, using a shuttle plasmid targeting the gp97 locus, and carrying the ul97 gene from hcmv strain towne. the resultant chimeric virus was replication competent, and was found to contain the hcmv ul97 by southern-blot and sequence analyses. northern-blot revealed that a hcmv ul97-specific transcript was expressed with late gene kinetics. western-blot, using a hcmv ul97-specific polyclonal antibody, detected protein in virus-infected cells. the chimeric virus was gcv-susceptible, compared to wild-type gpcmv, with an ic 50 of 15 m. chimeric virus also exhibited increased sensitivity to maribavir (mbv), exhibiting a 3-log reduction (compared to wild-type virus) in the presence of 50 m mbv, and an ic 50 of 5 m. to study the in vivo pathogenesis of chimeric virus, cyclophosphamide-immunocompromised strain two guinea pigs were challenged intraperitoneally, resulting in evidence of disseminated infection, and mortality. ganciclovir treatment (25 mg/kg/day) resulted in reduced weight loss, and mortality, compared to placebo. these studies confirm the key role of ul97 in cmv antiviral therapy, and demonstrate that a 'humanized' gpcmv can be generated with altered antiviral susceptibilities. genital herpes infections are a global health problem and impact hiv/aids epidemic. strategies to prevent transmission include treatment of infected subjects to suppress shedding and prophylaxis with vaginally-applied microbicides. we examined the in vitro and vivo activity of rep 9, a fully degenerate 40 mer phosphorothioated oligonucleotide against hsv-2 infection of human cervical cells and in a vaginal murine model. rep 9 has broad-spectrum anti-herpetic activity with potent in vitro activity against hsv-1, hsv-2, hcmv, vzv, ebv, and hsv-6 (vaillant et al., submitted for publication). at a concentration of 100 m, rep 9 inhibited 6-logs of hsv-2 infection if present during the entire experiment. synchronized infectivity assays demonstrate that, unlike sulfonated polyanions in clinical trials, which primarily block hsv attachment, rep 9 acts at multiple steps and inhibits binding, entry and post-entry gene expression. in our in vivo studies, mice were treated once intravaginally with rep 9 or pbs control at various times prior to vaginal challenge with a lethal dose of hsv-2 strain 186 (10 log 4 pfu). rep 9 prophylaxis provided protection to mice from hsv-2 infection and disease. protection was significant when challenged 30 min after treatment (p < 0.01). additionally, treatment with an analog of rep 9, which cannot activate tlr-9 mediated immune stimulation, was at least as active as rep 9, suggesting that direct antiviral activity and not stimulation of innate immunity is the mechanism of action in vivo. utilizing this analog, protection was significant when challenged 30 min after treatment (p < 0.001) with a trend toward protection when administered 60 min prior to challenge (p = 0.07). in summary, treatment with the rep 9 analog which has superior resistance to low ph and nuclease degradation was more effective than rep 9, in some experiments protecting 100% of mice from viral infection and disease. the testing of this ph resistant rep 9 analog in a gel formulation is currently underway. acknowledgement: supported by contract no1-ai-15438 from the virology branch, niaid, nih. a phosphorodiamidate morpholino oligomer (pmo) designed to hybridize to a highly conserved region including the aug translation start site of hcv, called avi-4065, has been evaluated for efficacy, toxicity, and pharmacokinetic properties. avi-4065 inhibits translation initiated at the aug start site with ec50 of 308 nm (2.1 ug/ml) and shows positive cooperativity. this pmo retains most of the activity in the presence of point mutations in the hcv genome. huh-7 cells were incubated with normal human serum (nhs) or hcv infected human serum (is) and hcv replication observed by rt-pcr. avi-4065 produced robust inhibition of hcv in a dose and sequence-specific manner. studies conducted in vivo with avi-4065 in the hcv infected trimera mouse (xtl) show reduction in viral titer which is dose dependent with approximately 90% of mice with undetectable viral titer and the remaining mice show 1 log reduction in viral titer with 0.1 mg/mouse/day for 7 consecutive days. the fractional bioavailability of avi-4065 from a sq dose is approximately 1. the apparent elimination half life in rat, nonhuman primate and humans was 2.3, 4.5 and 11.4 h, respectively. the volume of distribution ranged from 0.6 to 1.0 l/kg and the cmax is linearly related to the dose in mg/m 2 . a phase i study in healthy volunteers in which 14 daily sq doses of 50 and 100 mg has been completed. no serious adverse events have been observed. treatment of infected patients is currently planned. inhibition of hcv polyprotein synthesis is anticipated to contain therapeutic benefis of both protease inhibitors and polymerase inhibition. hcv infection can progress to fibrosis, reduced liver function, hepatocellular carcinoma, and death. currently, the standard treatment for hcv infection involves treatment with pegylated interferon in combination with the nucleoside analogue ribavirin. this treatment regimen effects a cure in approximately 40-60% of the genotype-1 (gt-1) population; therefore a significant unmet clinical need exists in hcv therapy. virus-encoded polymerases have proven to be excellent molecular targets for chemotherapeutic intervention in numerous viral mediated diseases. in the case of hiv, hbv and herpes virus infections, deoxy-nucleoside analogues, which act as chain terminating agents, have been shown to have invaluable clinical utility. by analogy, appropriate ribonucleoside analogues might be expected to inhibit the essential rna polymerase (ns5b) encoded by hcv. here we describe the preparation of nucleoside analogues as inhibitors of the hcv polymerase. in our design of nucleoside analogs as potential anti-hcv agents, we chose to investigate the effect of 4 -substituted ribonucleoside derivatives. we reasoned that after incorporation of a ribonucleoside containing a 4 -substituent, a disruption in elongation of the growing rna could be effected through either steric hindrance or via a conformational change of the carbohydrate moiety. our investigations on several such analogues will be presented. of particular interest is 4 -azido-cytidine, which shows good activity in the genotype 1b sub-genomic replicon (ic50 = 1.28 m) with no measurable cytotoxic or cytostatic behavior. in addition, we have shown that the triphosphate of 4 -azido-cytidine is a potent and highly selective inhibitor of ns5b (ic50 = 0.32 m). joanna e. boerner, sue ma, choilai tiongyip, michael p. cooreman, teresa compton, kai lin novartis institutes for biomedical research, 100 technology square, cambridge, ma 02139, usa current drug discovery efforts for hepatitis c virus (hcv) focus on developing specific inhibitors of two viral enzymes, ns5b polymerase and ns3-4a protease. however, resistant viral mutants are likely to emerge during therapy, compromising the effectiveness of these inhibitors. an alternative and complementary strategy is to target host factors that are also essential for viral replication. cyclophilins, a family of peptidyl-prolyl isomerases and the cellular targets of cyclosporin a (csa), present such an opportunity. it was reported recently that cyclophilin b bound to hcv ns5b polymerase and stimulated its rnabinding activity, and that these functions were blocked in the presence of csa (watashi k. et al., molecular cell 2005) . nim811, a csa derivative, is a more suitable candidate for hcv therapy because it binds to cyclophilins with higher affinity than csa while lacking the immunosuppressive activity associated with csa. using the hcv replicon system we demonstrated that nim811 exhibited potent anti-hcv activities in vitro. moreover, the combination of nim811 with a specific non-nucleoside inhibitor of hcv polymerase led to synergistic antiviral effects with no significant increase of cytotoxicity. resistant clones against both inhibitors were obtained in vitro, however, it was much more difficult to generate resistance against nim811 than the polymerase inhibitor. also, there was no cross-resistance between the two inhibitors. finally, addition of nim811 to the hcv polymerase inhibitor drastically reduced the emergence of resistance compared to polymerase inhibitor alone. taken together, nim811, with a novel mechanism of action and a favorable pharmacokinetics and safety profile, represents a promising clinical candidate for treating hepatitis c and provides a rationale for specific combination therapy. the nucleoside analog r1479 was identified as a specific inhibitor of hcv replication in subgenomic hcv replicon cells. r1479-tp is a competitive inhibitor of cmp incorporation by hcv polymerase ns5b. in a transient replicon system r1479 inhibited hcv rna replication driven by genotype 1b polymerase with similar potency as compared to that driven by genotype 1a polymerase. r1479-tp inhibited native hcv replicase and recombinant ns5b from genotype 1a and 1b with similar potency. in contrast, r1479-tp did not inhibit human dna polymerases alpha, beta or gamma, including reverse transcriptase activities of dna polymerases beta and gamma, which were highly sensitive to inhibition by azt-tp and 3tc-tp. no significant inhibition was observed with human rna polymerases i, ii and iii derived from hela cells. in addition, the functionally related native influenza virus rna dependent rna polymerase (rdrp) activity in vitro was not inhibited by r1479-tp at concentrations up to 1 mm, suggesting high selectivity for the hcv rdrp. thus, r1479 was identified as a potent and highly selective inhibitor of hcv polymerase mediated rna synthesis. guangxiang luo, zhaohui cai, chen zhang, kyung-soo chang, jieyun jiang microbiology, immunology, and molecular genetics, university of kentucky college of medicine, lexington, ky, usa the study of hepatitis c virus (hcv) replication and the search for specific antiviral agents against hcv infection have been hampered by the lack of an efficient stable cell culture system of hcv infection and propagation. we have successfully constructed stable human hepatoma cell lines that contain a chromosomally integrated-genotype 2a hcv cdna and constitutively produce and secrete high titers of infectious virus into the culture media. transcriptional expression of the full-length hcv rna genome is under the control of a cellular pol ii polymerase promoter at the 5 end and a hepatitis delta virus ribozyme at the 3 end. the resulting hcv rna was expressed and replicated efficiently, as shown by the presence of high levels of hcv proteins as well as hcv rna in the stable huh7 cell lines. hcv secreted from the stable cell lines was infectious, as determined by antibody neutralization, blockage of putative hcv receptors, and inhibition of hcv replication by interferon. our findings demonstrate the establishment of a stable cell culture system of infectious hcv production and propagation, which allows the study of the entire hcv infectious cycle. the stable hcv-secreting cell lines are now being pursued to develop high throughput screens for effective hcv inhibitors. additionally, we established a novel and powerful hcv replication system in the mouse hepatocyte and mouse embryo fibroblasts (mef). hcv rna was found to replicate efficiently in both pkr +/+ and pkr −/− mef cells, demonstrating that hcv rna replication in mef cells is a powerful system to study host-virus interaction by using diverse gene-knockout animals. interestingly, hcv rna replicates more efficiently in the pkr −/− cell than in the pkr +/+ cell, suggesting a role of pkr in the control of hcv rna replication. however, ifn inhibited hcv rna replication in the pkr −/− cell with an efficacy similar to that in the pkr +/+ cell, suggesting a pkr-independent antiviral mechanism. clearly both pkr-dependent and pkrindependent antiviral mechanisms are important for the control of hcv replication and the mediation of the ifn-induced anti-hcv response. our studies set a stage for the development of transgenic mouse models of hcv replication and open up new avenues to study hcv and host interactions in mefs derived from diverse gene-knockout animals. andrea cuconati 1 , haitao guo 2 , gael westby 1 , anand mehta 2 , timothy block 1,2 1 institute for hepatitis and virus research; 2 drexel institute for biotechnology and virology research, doylestown, pa, usa the high levels of hepatitis b surface antigen (hbsag)-bearing non-infectious particles in the serum of infected individuals is thought to play a role in suppressing hepatitis b virus (hbv)specific immune response by titering out hbv-specific antibodies and lymphocytes. current hbv therapeutics do not directly reduce this viral antigenemia. our group has focused on the enhancement of the immune response through the inhibition of viral antigen secretion in the infected hepatocytes, with the therapeutic goal being the use of hbv vaccination for the treatment of acute and chronic infection. the high-throughput screening of a small molecule library of 80,288 drug-like compounds was undertaken to discover novel inhibitors of hbsag secretion. using the stably hbv-transfected, human hepatoma cell line hepg2.2.15, we developed an hts-compatible elisa protocol for the detection of hbsag secreted in the culture media. the screen resulted in 1758 initially positive hits, a hit rate of 2.2%. subsequent retesting for activity and toxicity by mtt assay has narrowed the number of confirmed, non-toxic hits to 77, currently categorized in twelve chemical series. we have previously reported on a trio of related pyrazolo-pyridines with ec50 measurements below 5.0 m and cc50 measurements >50.0 m. nascent structure-activity relationship (sar) suggests that a central moiety of the molecules is essential to activity, with an aromatic side group contributing to potency. among recently confirmed inhibitors, two currently under investigation include: (1) an isobutyl-acetamide with an ec50 of 87.0 nanomolar, and a cc50 of >50 m, and (2) a carbothiamide with an ec50 of 1.6 micromolar and a cc50 of >50 m. measurement of secreted hbv l and m antigens and cellular markers indicated that the pyrazolo-pyridines are not specific inhibitors of viral antigens, while the isobutyl-acetamide and the carbothiamide are indeed specific. measurement of intracellular viral dna indicated that none of these molecules are inhibitors of replication. we will be reporting on our studies of the potency, specificity, and potential mechanisms of action of these novel anti-hbv compounds. background: entecavir (etv) is a potent competitive inhibitor of hepatitis b virus (hbv) polymerase with activity versus all three enzymatic functions including priming, minus, and plus strand dna synthesis. virologic rebound due to etv resistance (etvr) has only been observed in lamivudine resistant (lvdr) hbv (m204v/i ± l180m), and requires at least one additional change in the reverse transcriptase domain (rt) at residues t184, s202, or m250. these substitutions surround the dntp binding site or primer grip of rt. the objectives of this work were to further characterize etvr and its mechanism(s) using cell culture, in vitro enzyme, and molecular modeling studies. methods: hbv cell culture assays used transfected hepg2 cells and quantitation of released, immunocaptured hbv nucleocapsids. gradient-purified intracellular nucleocapsids were used for in vitro rt assays. a 3d homology model based on the hiv-1 rt structure was used to model resistance changes in hbv. results: reduced etv susceptibility of etvr hbv was observed both in culture and enzymatically in vitro. kinetic studies showed various etvr substitutions in lvdr hbv selectively reduced etv-triphosphate (etv-tp) binding (k i ) to rt without markedly changing the affinity for dgtp (k m ) or inhibition by ddgtp. etvr rts also displayed reduced enzymatic activity (k cat ) relative to wildtype and etvr hbv appeared growth impaired. modeling studies suggested a novel etv-tp binding pocket in hbv rt that became constrained with etvr changes. m250 changes in the primer grip region of rt were unique in that resistance was primarily seen during synthesis of minus strand dna. etvr changes in the absence of lvdr substitutions had greatly reduced impacts on etv susceptibility, confirming models suggesting etvr is imparted through lvdr changes. summary: etv provides a high genetic barrier to resistance, requiring additional changes at residues t184, s202 or m250 along with pre-existing lvdr substitutions m204v/i ± l180m. kinetic parameters and molecular modeling indicated that etvr substitutions selectively affected etv-tp binding and reduced the replication capacity of hbv. a nonhuman primate (nhp) model of classical, lesional smallpox has been used to test the efficacy of intravenous (iv) cidofovir treatment. cynomolgus macaques were infected with a high dose (10 8 pfu iv) of variola to produce an artificial primary viremia, and then treated with cidofovir at 0, 24, or 48 h postinfection (pi). later treatment times were not evaluated. treatment at 24 or 48 h pi halted increases in peak blood viral genome titers measured by quantitative taqman-mgb real-time pcr, which were more than 10-fold less in cdv-treated animals compared to placebo. historically, the number of pox lesions provided the best correlation with human smallpox clinical severity, and cdv treatment in our model significantly reduced maximum pox lesion counts by >90%; the number and size of skin lesions, and in untreated animals contributed significantly to the total viral burden with lesions containing 10 9 -10 10 genomes/g. to better understand the role of viral burden and disease progression in major organ systems, a serial sample study was undertaken. in untreated animals at 24 h pi, viral replication in spleen exceeded 10 9 genomes/g while liver and bone marrow yielded 10 8 genomes/ml. in comparison, titers in other tissues ranged between 10 5 and 10 6 genomes/g and blood yielded 10 4 genomes/ml at 24 h, suggesting that the liver, spleen, and marrow may be initial sites of replication. levels of virus in the bone marrow reached a peak of approximately 10 10 genomes/g at day 5, then decreased to quantities consistent with those in blood. viral load in the blood increased with time, peaking around days 7-9 at 10 8 genomes/ml. virus was also detected in intestine, skeletal muscle, and late in infection, testes. the ability to successfully treat with cdv 24 h pi despite early extensive organ infection in the accelerated nhp variola model suggests that this treatment could be effective in reducing viremia and mortality after onset of symptoms in human smallpox, which demonstrates a more protracted disease course. work involving variola virus conducted in who-sanctioned cdc, atlanta bsl-4 laboratory. earl kern 1 , kathy keith 2 , robert jordan 2 , dennis hruby 2 , debra quenelle 2 1 department of pediatrics, university of alabama school of medicine, birmingham, al, usa; 2 siga technologies, inc., corvallis, or, usa although cidofovir (cdv) has been approved as an investigational new drug for emergency treatment of smallpox, its lack of oral activity and dose limiting toxicity dictates a need for continued development of better therapeutic agents for this potential bioterror disease. it has been reported previously that st-246, a low-molecular weight compound, inhibits replication of all the orthopoxviruses in vitro and protects mice infected with vaccinia or ectomelia virus. in the present study, we have utilized cowpox virus (cv) and vaccinia virus (vv) infections in vitro and in vivo to evaluate the efficacy of st-246 for treatment of orthopoxvirus infections. in plaque reduction assays in human foreskin fibroblast cells, both cv and vv were inhibited by about 0.1-0.5 um of st-246. for in vivo studies, st-246 was administered once daily by oral gavage to mice using 100 mg/kg for 5, 7, 10, or 12 days beginning 4 or 24 h after intranasal inoculation with vv or cv. st-246 was highly effective (p < 0.001) in preventing mortality due to vv or cv even when treatment was delayed up to 24 h post-infection. a dosing duration of 5 days was adequate for vv infected mice, but duration of 7 days or longer was required for efficacy in cv infected mice. when st-246 was given once daily for 14 days at 100, 30, or 10 mg/kg daily at 24, 48, or 72 h post-cv inoculation, mortality was significantly altered at all dosage levels and time points. to determine the effect of treatment on virus replication in target tissues, mice were inoculated with cv or vv and treated once daily with 50 mg/kg of st-246. on various days post-infection tissues were harvested and assayed for virus. in cv or vv-infected mice, st-246 treatment successfully reduced virus titers from 3 to 5 logs 10 in liver, spleen, and kidney. little effect was noted in lung tissue. these results indicate that st-246 has significant activity against vv and cv infections in vitro and in vivo and may be a potential chemotherapeutic agent for treatment of human orthopoxvirus infections. cidofovir (hpmpc) is a broad-spectrum anti-viral agent that is used (vistide ® ) to treat aids-related cmv retinitis. currently, cidofovir is of particular interest as a potential therapy for orthopox virus infections, including smallpox. an important limitation of cidofovir and analogous nucleotide drugs in a therapeutic role is their low oral bioavailability and poor transport into cells. in principle, bioavailability of a drug can be improved by structural modification targeting transporters expressed in human intestine. to be effective, the transported prodrug must be cleaved by endogenous enzymes to its parent compound. we will present synthetic studies of novel cidofovir and cyclic cidofovir (chpmpc) prodrugs incorporating amino acids or small peptides, comparing different drug-amino acid linkage strategies. the compounds were evaluated for transporter-mediated uptake and cellular and plasma hydrolysis. the results will be compared with similar studies carried out on a series of peptidomimetic conjugates of foscarnet, the trisodium salt of phosphonoformic acid (pfa), an anti-viral agent that also has very low oral bioavailability and poor cell penetration. the question addressed in this study is if wnv-reactive antibody can improve disease signs in a hamster model after the virus is demonstrated to be in the brain. the hypothesis is based on the high activity of a humanized monoclonal antibody, he16, in a mouse model when administered later in infection (oliphant et al., 2005. nat. med. 11, 522) . in this study, virus was demonstrated to be in the brains of hamsters at 5 days post-viral injection (dpi) by cell culture assay, quantitative rt-pcr, and immunohistochemical staining of wnv in neurons. eighty percent of hamsters treated i.p. 5 dpi with 100 mg/kg of humanized monoclonal antibody, he16, survived wnv disease, whereas, 37% of placebo-treated hamsters survived ( *** p < 0.001). if administered at 2 dpi, 100% survived. we tested the hypothesis that he16 is effective if delivered directly into the brain instead of by peripheral administration. the antibody was delivered into the brain 5 dpi using convectionenhanced delivery through a cannula implanted into the brain. the he16 was detected in the cns, but none was detected in the kidney. the survival of he16-treated hamsters was 88% as compared to 22% of placebo-treated animals ( *** p < 0.001). for additional proof, the majority of hamsters having wnv in their cerebrospinal fluid, a marker for cns infection, were protected with he16 administered i.p. at 5 dpi. this humanized monoclonal antibody, therefore, is a possible treatment for the post-exposure, wnv-infected humans that develop signs of neuroinvasive disease. acknowledgement: supported by contract no1-ai-15435 from the virology branch, niaid, nih, and grant 1-u54 ai06357-01 from the rocky mountain regional centers of excellence, nih. hemorrhagic fever viruses are of serious worldwide health concern as well as potential biological weapons. lassa fever virus in particular annually infects several hundred thousand individuals in west africa, and the export of this pathogen outside of this region, either intentionally or unintentionally, presents a serious risk to the developed countries of the world. the cdc and niaid have identified lassa fever virus as a category a priority pathogen, indicating the highest degree of threat to public health. no arenavirus-specific antiviral drugs are currently approved for use in humans. the purpose of siga's biodefense program is to develop safe and effective drugs for preventing and treating diseases caused by category a viruses. to that end, a large and diverse library of small molecule compounds was screened using a viral pseudotype assay to identify inhibitors that target the essential lassa surface glycoprotein (gp) and thus block viral entry into the host cell. twenty-six compounds were identified as quality hits, as defined by potency, selectivity, and chemical tractability. antiviral activity against authentic lassa fever virus was assessed in cell culture through a collaboration with colleagues at usamriid. a number of these potent antiviral compounds and their related analogs have exhibited informative chemical structure-biological activity relationships (sar). two potential lead compound series have emerged from these studies, each with 50% effective concentrations (ec50s) of less than 100 nm against lassa fever virus and with ec50s of less than 2 nm against lassa gp-pseudotyped virus. characterization of the in vivo properties of these compounds is underway. the in vitro antiviral potency and selectivity, animal pharmacokinetics, and the development process will be presented. these inhibitors represent an important step toward the development of a small molecule antiviral drug for lassa fever virus. sven enterlein 1 , pramila walpita 1 , allison groseth 2 , heinz feldmann 2 , ramon flick 1 1 university of texas medical branch, department of pathology, galveston, tx, usa; 2 national microbiology laboratory, public health agency of canada, winnipeg, man., canada nipah (niv) virus (family paramyxoviridae) is a recently emerged human and animal pathogen that can cause severe encephalitis with fatality rates of up to 70%. since no treatment or vaccination is available, and cross-species spread was observed, the virus has been classified as biosafety level 4 (bsl-4) agent. to avoid bsl-4 containment for the study of cis-acting signals as target for antiviral strategies, we used an optimized plasmid-driven t7 minigenome rescue system (without the need for recombinant vaccinia virus mva-t7) as well as an newly established rna polymerase i-based approach. minigenome rescue is based on transfection of the minigenome niv-cat and the plasmids encoding for the three nucleocapsid proteins n (nucleoprotein), l (polymerase), and p (phosphoprotein) and measured by enzymatic cat assays. we used the established plasmid-based minigenome rescue systems to screen for potential antiviral compounds. in a first step we tried to determine the optimal strategy for the delivery of small hairpin (sh) interfering rna molecules. for this we compared three shrna delivery systems against another bsl4 agent-reston ebolavirus (family filoviridae); (i) plasmid-mediated pol i and (ii) pol iii-driven shrnas, and (iii) exogenously (t7) produced shrna, for their ability to induce gene silencing. interestingly, beside the in vitro-generated or pol iii-driven shrnas, pol i transcripts showed very efficient inhibition of minigenome rescue. however, the most efficient delivery method was transfection of in vitro transcribed shrnas. we will present the results of this comparison and, based on the most efficient approach, also first results of shrnas targeted either to niv n, p, and l genes or to the leader/trailer noncoding regions to interfere with minigenome replication. conformative data with live virus experiments under bsl4 conditions will be included. filoviruses, which include ebola virus and marburg virus, are among the most notorious human pathogens because they cause sporadic outbreaks of severe hemorrhagic fever. unfortunately, very few therapeutic agents are available to treat infections with these viruses. antiviral screening methods that determine the effect of compounds on viral replication involve working with infectious virus, which is obviously not practical for these biosafety level 4 (bsl-4) agents. we developed an antiviral screening method based on a cell-based, infection-independent, ebola subgenomic replication system in which the expression of an easily measurable enzyme is dependent on the rna replication and transcription factors of ebola virus. using this system we screened a synthetic compound library for antiviral activity against ebola virus and have identified a number of inhibitors. we also used it to identify a peptide inhibitor directed against vp30. anti-ebola virus activity for many of the inhibitors was confirmed in a viral replication assay using a gfp-expressing zaire '76 strain of ebola virus. fifty-two small molecule inhibitors from at least six classes of compounds had ec50 values in the low micromolar range and good selectivity. several of these compounds have promising chemical, biological, and pharmacological profiles to pursue as potential anti-filovirus drugs. we are currently preparing to test these compounds in a mouse model of ebola virus. we have also begun a lead optimization program to improve antiviral potency and selectivity of aryl sulfonamide and 4-aminoquinoline compounds. acknowledgement: supported by nih r44 ai052917-02 and r01 ai066502-01. human papillomavirus (hpv) has been a difficult virus to target by traditional antiviral methods due to its small size, its small number of obvious therapeutic targets, and its resistance to propagation in vitro. nevertheless, antiviral compounds that reduce hpv dna load have the potential to prevent carcino-genic progression in infected patients. to that end, we developed an approach that dramatically reduces the hpv episomal dna load of keratinocytes in vitro by targeting viral dna sequences. pyrrole-imidazole polyamides, with some containing fluorescent probes to aid in cell localization studies, were designed to recognize the hpv31 ori. all fluorescent compounds rapidly localized to the nucleus of cultured keratinocytes following addition to the culture media. the compounds were then tested for their ability to alter keratinocyte hpv31 episomal dna content. two of the 19 compounds caused a dose-dependent reduction in hpv31 episomes as measured by taqman tm realtime pcr. while control and vehicle-treated cells maintained ∼1000 copies of hpv31 per cell, compounds 2-ta and 4-ta both reduced hpv31 dna levels to below 50 copies per cell after 48 h incubation with 10 m compound. an alternative taqman tm amplicon within the hpv31 e7 gene produced identical results. a multiplexed taqman tm real-time pcr reaction that followed the ratio of hpv31 dna to the human apoe gene also demonstrated dramatic loss of hpv31 dna copies, further confirming our initial observations. finally, cells were treated with polyamides for 48 h, polyamide-containing media was removed, and episome levels were followed for 8 days. at day 6, 4 days after removal of polyamide and 3 days after sub-culturing of the cells, viral episome levels remained approximately 60% lower than control samples. by day 8, 6 days after removal of polyamide, viral dna levels were beginning to recover but still remained significantly lower than control samples. together our results demonstrate that targeting the hpv origin of replication with dna-binding compounds dramatically reduces episomal dna levels. small interfering rnas (sirnas) are potent tools for gene down-regulation but are minimally stable in cells. to improve the efficacy of sirna, we replaced non-bridging oxygens in the phosphodiester linkages of natural rnas with bh3 groups. the resulting boranophosphates have unique properties, including enhanced nuclease resistance, altered hydrogen bonding of the phosphate, different interactions with metal ions, and increased thermal stability of rna:rna and rna:dna duplexes. anti-egfp sirnas containing boranophosphate modifications were prepared by in vitro transcription with t7 rna polymerase from ribonucleoside 5 -(alpha-p-borano)triphosphates, as well as normal and phosphorothioate sirnas. after confirming the presence of the borane modifications with maldi-ms, several properties of borano-modified sirnas were investigated: (1) the double stranded rna with borane modifications maintained the a-form conformation characteristics according to the circular dichroism (cd) spectra; (2) the borane groups in the sirnas increased the thermal stability, with an enhancement of t m by 0.5-0.8 • c per modification; and (3) sirnas with borano-modifications were shown to be at least 10-fold more resistant to rnase a digestion than normal ones. when these modified sirnas were used to down-regulate egfp expression in hela cell cultures, it was found that: (1) borano-modified sirnas were consistently more effective than sirnas containing the corresponding phosphorothioate modifications; (2) borano-sirnas were more effective than normal sirnas provided that the center of the antisense strand was not heavily modified; (3) borano-sirnas were more potent than normal or phosphorothioate sirnas at lower concentrations; and (4) finally, the silencing activity of boranophosphate singlestranded sirna (ss-rna) was comparable to that of unmodified ds-sirna. the borano ss-rna had excellent maximum silencing activity and was highly effective at low concentrations, and silencing activity was durable up to one week after transfection. results with anti-hpv sirnas will be discussed. boranophosphate modification is a potential new class of anti-viral therapeutic agents. this report describes the antiviral structure activity relationships that led to the discovery of phosphonomethoxy-2 -fluoro-2 ,3dideoxydidehydroadenosine (fd4ap, gs9148), a novel ntrti, with an excellent resistance profile toward hiv-1 variants containing major n(t)rti resistance mutations. methods: phosphonomethoxy analogs on purine and pyrimidine dideoxydidehydro (d4) and dideoxy (dd) ribose scaffolds were prepared. antiviral activity was measured against wildtype and n(t)rti-resistant recombinant viruses using cytopathic assay in mt-2 cells. mitochondrial toxicity was assessed in hepg2 cells by measuring mitochondrial dna content. results: the d4 scaffolds displayed superior antiviral activity compared to the dd scaffold and adenine was superior to other nucleobases. phosphonomethoxy-2 ,3dideoxydidehydroadenosine (d4ap) inhibited hiv-1 replication with a mean ec50 of 2.1 m and an 0.8-, 2.9-, and 2.9-fold change in potency against viruses containing m184v, k65r, and 6 thymidine analog mutations (tams), respectively. further exploration of d4ap was limited by its mitochondrial toxicity, which was then addressed in 2 ways: (i) preparation of l-d4ap or (ii) 2 fluorine substitution. l-d4ap exhibited an ec50 of 5.9 m but had substantially reduced potency (14-fold) toward m184v mutant viruses. fd4ap exhibited an ec50 of 12.3 m, with 0.8-, 1.2-, and 3.5-fold change in potency against viruses containing m184v, k65r, and 6 tams, respectively. no cytotoxic effects were measured up to 1 mm in mt-2 cells and no effects on mitochondrial dna were detected up to 300 m in hepg2 cells for both fd4ap and l-d4ap. conclusion: fd4ap is a novel phosphonate ntrti with antiretroviral activity toward wild-type and resistant mutant hiv-1 strains. compared to d4ap, the 2 -fluorine atom significantly improved the in vitro toxicity profile while retaining the favorable resistance profile. in subsequent studies, the monoamidate prodrug strategy was applied to fd4ap to achieve optimal in vivo pharmacokinetic properties. entry inhibitors, and ccr-5 antagonists in particular, have become one of the most actively pursued treatments for hiv within the pharmaceutical industry. recently, multiple groups have disclosed piperidine-based ccr-5 antagonists that -to the medicinal chemist's eye -might appear to share a common three-point pharmacophore comprised of a tertiary amine, a phenyl ring, and a carboxamide or sulfonamide group. in several of these cases, these pharmacophoric elements are tethered together by a flexible, aliphatic chain. we sought to improve the potency of and introduce structural novelty into this class of compounds by rigidifying this tether. herein, we describe stereoselective syntheses and sar of a series of ccr-5 antagonists wherein the tether has been replaced with four stereochemical isomers of a rigidified cyclopropyl scaffold. the regulation of hiv transcription is a complex, multistage process that requires the concerted action of viral and cellular proteins. we discovered the n-aminoimidazoles (naims) as a unique class of hiv inhibitors targeted at the viral transcription level. a prototype naim, nr-818, prevents the reactivation of dormant virus by inhibiting both the hiv-1 p24 and viral mrna production from latently hiv-1-infected cell lines upon stimulation with tnf-␣, pma, or tsa. extensive research revealed that nr-818 was unable to inhibit the nf-b activation pathway or chromatin remodeling at the viral promoter, both known to be crucial for viral transcriptional activation. focusing on the viral transcription process, chromatin immunoprecipitation (chip) experiments revealed that nr-818 was able to inhibit the ser5 phosphorylation of the c-terminal domain (ctd) of rna polymerase ii. this step is mediated by the cdk9 subunit of p-tefb, which is recruited to the viral promoter by the hiv-1 tat protein. since we did not find an inhibition at the level of cdk9 activity or tat-mediated transcription in tat-expressing cell lines transiently transfected with a ltr-gfp construct, we infer that nr-818 must interfere with the transcription process by a unique mode of action. evidence points towards a kinase, not belonging to the cdk family, to be the target of the naims, resulting in an antiviral action at the level of retroviral transcription. clara e. cases-gonzález 1 , sandra franco 2 , miguel a. martínez 2 , luis menéndez-arias 1 1 centro de biología molecular "severo ochoa", csic-uam, madrid, spain; 2 fundació irsicaixa, hosp. university germans trias i pujol, badalona, spain a ser-ser insertion at codons 69-70 together with substitutions t69s and t215y in the reverse-transcriptase (rt)-coding region of hiv-1 are known to confer resistance to zidovudine (azt) and stavudine (d4t). phenotypic resistance correlates with increased atp-dependent phosphorolytic activity on inhibitor-terminated primers. we have previously shown that an rt derived from a clinical isolate (ss rt) that contained the insertion and 10 additional mutations related to drug resistance (including t215y) showed >10-fold increased unblocking activity on azt-and d4t-terminated primers, when compared with an rt containing the insertion together with mutations t69s and t215y, in an otherwise wild-type bh10 sequence. these results suggested that other mutations associated with the complex t69sss/t215y in clinically relevant rts contributed to increase atp-mediated excision activity and conferred high-level resistance to azt and d4t in phenotypic assays. to identify residues increasing the excision activity, we obtained recombinant enzymes bearing ss rt residues 1-135 and wild-type bh10 rt residues 136-560 (l1 rt), or residues 1-135 of the bh10 rt and 136-560 of the ss rt (l3 rt), as well as an l1 rt variant with the substitution t215y (l2 rt) and an l3 rt derivative with t69sss (l4 rt). additional rts containing mutations m41l, a62v, or k70r together with the combination t69sss/t215y in the bh10 background were also obtained. atp-mediated excision activities on azt-and d4tterminated primers were determined and the effects of mutations were tested in phenotypic assays using recombinant hiv-1. the l2 rt containing mutations t69sss/t215y and additional changes in the n-terminal region showed the highest atp-dependent phosphorolytic activity on blocked primers, giving values similar to those reported for the ss rt. results were consistent with phenotypic data. in contrast, l1, l3, and l4 rts displayed low-level activity. further experiments revealed that three amino acid changes at the n-terminal region of the polymerase (m41l, a62v and k70r) were responsible for the increased excision activity shown by rts bearing mutations t69sss and t215y. from a series of phenyl-substituted thiazolobenzimidazoles, several compounds were identified as selective inhibitors of coxsackie b virus replication in vero cells. a structure-activity relationship was established, from which the 6-trifluoromethyl substituted analogs emerged as the most potent congeners. the compounds were active against all six coxsackie b strains tested. the in vitro antiviral activity of one of the most selective compounds, i.e. chi-033, was assessed by (i) mts-based cytopathic effect assays, (ii) virus yield reduction assays, (iii) real-time quantitative pcr (rt-qpcr) and (iv) by monitoring viral antigen expression. in all assays a clear concentration-response effect was obtained. the 50% effective concentration (ec50) was 0.30 ± 0.18 g/ml, while the cc50 (50% cytotoxic concentration) of chi-033 for vero cells was more than 100 g/ml, thus resulting in a selectivity index of >500. detailed single cycle time-of-drug-addition studies (in which viral replication was monitored by means of rt-qpcr) revealed that the compound interacts with viral replication at a time that coincides with the onset of intracellular viral rna synthesis. chi-033resistant virus is being generated by culturing the virus in the presence of increasing drug concentrations. drug-resistant virus will be genotyped, which should allow us to identify the (putatively viral) molecular target of this class of compounds. retroviruses 42 hiromichi tanaka 1 , kazuhiro haraguchi 1 , hiroki kumamoto 1 , takao nitanda 2 , masanori baba 2 , ginger e. dutschman 3 , yung-chi cheng 3 1 school of pharmaceutical sciences, showa university, tokyo, japan; 2 center for chronic viral diseases, kagoshima university, kagoshima, japan; 3 school of medicine, yale university, new haven, ct, usa our recent research program on the development of synthetic methods for 4 -carbon-substituted nucleosides has led to a new strategy, ring opening of 4 ,5 -epoxy-nucleosides with organoaluminum and organosilicon reagents. this enabled us to introduce alkyl, alkenyl, and alkynyl groups to the 4 -position. as a result of this study, 4 -ethynylstavudine (4 -ed4t) was found to be more anti-hiv active than the parent compound stavudine (d4t). this compound (4 -ed4t) has several additional appeals as a promising anti-hiv agent: much less toxic to various cells and also to mitochondrial dna synthesis, better substrate for human thymidine kinase than d4t, very much resistant to catabolism by thymidine phosphorylase, its activity enhances in the presence of a major mutation k103n known for nnrti-resistant hiv. in this conference, we present the synthesis and sar studies of 4 -ed4t analogues modified mainly in the sugar portion. negatively charged polymers (np) possess a broad immunoadjuvant and antiviral activity topically useful for vaccine, drug, and microbicide development. but their efficiency is limited over a reversibility of electrostatic kind of interference with virusspecific nano-objects. to overcome this limitation the purposemade intra-molecular modifications of np were studied among non-toxic maleic acid co-polymers (npsa), dextran and chitin derivatives (npps) within varied alicyclic modifiers application. the configurationally flexible alkyls (i), as non-alicyclic control, are ineffective synergist for np antiviral potency. monocycles (ii) are moderate active too. on the contrary the hardconformation frame-structured spheroids (iii-vi) exhibit ability (at optimal macromolecular parameters) to be super-effective synergists for strength and diapason of np antiviral action. unlike small molecular iii/iv-containing prototypes (amantadin, rimantadin, deitiforin, etc.), narrowly-effective inhibitors mainly of influenza a viruses, the np-coupled modifications become effective also against many other viruses, including the drugs resistant strains [antivir. res. 46 (1), 44]. in focus of the anti-hiv potency the ivs provide a 10-100-fold elevation of np activity. the more available and less toxic iii species are similarly active, but iii* (with spatial-optimally contactable double bond due to the exo-configuration) turns out the best synergist 20-500-fold amplifying the anti-hiv-1 selectivity up to is∼10000. augmentation of the frame cycles from iii-iv toward v-vi results in no essential enhancement of antiviral activity, but stimulates toxicity. the recently involved in the investigation vii, cholesterol-like systems, as tools for novel raft-targeted strategy, demonstrate capacity for at least 10-fold amplification of anti-hiv-1 potency our earlier studies showed that esterification of cidofovir (hpmpc) with alkoxyalkanols increased antiviral activity by more that two logs and promoted oral bioavailability. to evaluate this approach with purine based nucleoside phosphonates, we synthesized several alkoxyalkyl esters of acyclic purine phosphonates such as 2,6,-diamino-(9-[2-phosphonomethoxyethyl]purine (pme-dap) and 2-amino-6-cyclopropylamino-(9-[2phosphonomethoxyethyl]-purine (pme-cpr-dap) these purine phosphonates have been reported to be active against a wide range of viruses such as human immunodeficiency virus (hiv-1), other retroviruses, herpesviruses, poxviruses and hepatitis b virus. for this study several alkoxyalkyl analogs of acyclic 2,6diaminopurine nucleoside phosphonates were synthesized and evaluated against hiv-1. the alkoxyalkyl esters were more inhibitory than the unmodified compounds in p24 reduction assays in mt-2 cells infected with hiv-1. for example, hexadecyloxypropyl (hdp) and oleyloxyethyl (ole) esters of pme-cpr-dap were >3 logs more active than unmodified pme-cpr-dap. in spite of increased cytotoxicity in mt-2 cells, the selectivity indexes are more than 10-fold higher then for unmodified compound. in conclusion, esterification of pme-dap and pme-cpr-dap with hexadecyloxypropyl-or oleyloxyethyl-residues greatly increased their antiviral activity and selectivity against hiv-1 in vitro. victor kuz'min 1 , eugene muratov 1 , anatoly artemenko 1 , ludmila koroleva 2 , vladimir silnikov 2 , v. lozitsky 3 , a. fedchuk 3 1 a.v. bogatsky physical-chemical institute, odessa, ukraine; 2 institute of chemical biology and fundamental medicine, novosibirsk, russian federation; 3 ukrainian mechnikov research anti-plague institute, odessa, ukraine "chemical" ribonucleases hold promise as tools for studying the structures of rnas and rna-protein complexes, as reactive groups in conjugates intended for cleavage of particular rnas, as therapeuticals inactivating virus genome rnas or certain mrnas, and as a promising antiviral agents. drug design and development of new medicines directed against hiv are permanently actual tasks. the usage of modern quantitative structure-activity relationship (qsar) methods could allow us to solve these problems more effectively. the objective of the present work is qsar analysis of antiviral activity of various tetrapeptides-artifical ribonucleases and consequent molecular design of new antiviral agents. qsar approach based on simplex representation of molecular structure (sirms) has been used for the solution of the formulated problem. usage of sirms allows us to develop the molecular design of the new effective antiviral agents. thorough researches of relationship between antiviral activity (hiv-1, % of rna p-o bond cleavage) and a structure of artifical ribonucleases have been carried out. statistic characteristics for pls (partial least squares model) are quite satisfactory (r 2 = 0.836, q 2 = 0.788). on the base of these models the molecular fragments with positive or negative influence on the explored property have been determined. thus, for example, guanidine and triethylenediamine fragments promote antiviral action. it gives a possibility to realize based on elucidated rules molecular design of compounds with the high level of antiviral activity. the results of prognosis are verifying by the experimental investigations. thus, quite adequate simplex qsar model "anti-hiv activity-artifical ribonucleases structure" was obtained and used for drug design. the cyclotriazadisulfonamide (cada) compound specifically down-modulates the cd4 receptor expression on the surface of lymphocytes and monocytes/macrophages, the primary receptors utilized by hiv for infection of its target cells. cada thus inhibits the entry of hiv and hhv-7 (vermeire et al., 2002. virology 302, 342-353) . cada chemotherapy may not be susceptible to the production of drug resistant strains of viruses, as its mechanism of action is completely different from those of any other anti-hiv drugs currently in clinical use. the cd4 down-modulating and antiviral potencies of more than 25 cada analogs have been described (vermeire et al., 2003. mol. pharmacol. 63, 203-210) . structural modifications of cada were made to increase potency, reduce cytotoxicity, and improve physical properties. several head group analogs were synthesized with polar groups and good leaving groups ( fig. 1) . the anti-hiv and cd4 down modulation activities of these compounds are being studied. some of these head groups may regenerate the double bond of cada by elimination reactions, potentially producing water-soluble pro-drugs. isocada (sa05), an isomer of cada, was synthesized by cyclization of 1,5,7-triazabicyclo-[4.4.0]dec-5-ene (tbd) (fig. 1 ). this structural modification may reveal a relationship between the symmetry of the molecule and its biological activity. two new fluorine-containing analogs were also synthesized by modifying the toluenesulfonamide side arms (fig. 1) . the anti-hiv and cd4 down modulation activities of these new cada analogs are summarized. the center for drug discovery, university of georgia, athens, ga 30602, usa drug discovery targeted at the elusive viral enzyme, hiv integrase, has not resulted in a single fda-approved drug. in this presentation we describe our molecular modeling studies with conceptually novel inhibitors of hiv integrase that also possess potent in vitro anti-hiv activity. docking was performed on the catalytic core of integrase represented by chain c of pdb structure code 1bl3. building of molecules and primary modeling was done with sybyl 7.1 on a silicon graphics onyx3 (r14000) workstation. the program gold 3.0 (genetic optimization for ligand docking) was used extensively in evaluating the docking poses of these compounds with the active site of hiv integrase and to give information on key residues involved in the recognition and binding of these ligands. the gold function consists of three basic components: protein-ligand h-bonding energy, protein-ligand van der waals energy, and ligand internal energy. post-processing gold output was done with the program silver 1.1, a utility program supplied with gold for evaluating hydrogen-bonding interactions, metal coordination and van der waals factors. for comparison purposes, additional docking was performed using other docking protocols, notably the sybyl module flexx. data obtained from these and related studies including binding poses, binding affinities, functional and conformational considerations, and gold function scores will be presented and explained. the center for drug discovery, university of georgia, athens, ga 30602, usa hiv integrase is essential for hiv replication and is an attractive target for drug discovery against aids. however, research efforts on drug discovery pertaining to hiv integrase have not resulted in a single fda-approved drug for which mechanism of action is inhibition of hiv integrase. recently, we have been exploring a novel class of diketo acids that are constructed on nucleobase scaffolds and that have a specific arrangement of the functional and hydrophobic group on the scaffold. these compounds are inhibitors both key steps of hiv integrase. one lead compound from this group has also been found to have remarkable in vitro anti-hiv activity. however, the syntheses of the inhibitors are quite challenging. this presentation will describe the synthetic methodologies specifically developed in our laboratory for the preparation of some representative examples of these integrase inhibitors. purification approaches to produce highly purified compounds for biological studies will be explained. structural, functional and conformational data obtained from extensive spectroscopic studies will be discussed. representative anti-hiv integrase data and in vitro anti-hiv screening results will be presented. we have recently reported the synthesis and antiviral activities of a ring-expanded ("fat") nucleoside analogue, called nz-51, that inhibits both hcv and hiv in vitro with ec 50 values ranging in micromolar concentrations or less, with little or low toxicity to the host cells. in this part i of the presentation on this subject, we report our preliminary findings on the mechanism of anti-hiv activity of this compound, along with the synthesis and antiviral activity of a few additional analogues. in view of the fact that a number of hiv patients also suffer from hcv as a major coinfection, and that a number of them ultimately die of end-stage hcv-related complications including liver cirrhosis and hepatocellular carcinoma, a drug with dual inhibitory characteristics against both viruses is highly desirable and timely. marina burshtein 1 , alexander serbin 2 , alissa bukrinskaya 1 d.i. ivanovsky institute of virology, moscow, russia; 2 health research and development found, moscow, russia introduction: amantadine is a well-known effective antiinfluenza drug. it was modified to enhance its antiviral activity by chemically linkage with the water-soluble polyanionic matrix via different spacer groups. the other group of used compounds was norbornene derivatives, as norbornene is an adamantane analogue on anti-influenza activity. methods: the absence of cytotoxic effect was shown by mtt test for estimating cytotoxic dose (ctd50). the antiviral effect of the compounds was analyzed in lymphoblastoid mt-4 cells and in hela cd4+/b-galactosidase cells ("magi" cells). the effect of the compounds was registered by immunoblotting of cell lysates and by measuring of b-galactosidase activity. results: the strong inhibition of hiv-1 replication was observed when the compounds were added with the virus and was expressed even when the compounds added with the virus were removed 1 h after infection. the anti hiv-1 effect of the compounds was gradually decreased if they were added 1 and 2 h after infection, no inhibition was observed when the compounds were added 4 h after infection. the compounds did not impair the virion structure. adamantane and norbornene derivatives were shown also to inhibit azt resistant viral strains. conclusion: adamantane and norbornene were shown to be active hiv inhibitors with the high selectivity index. the compounds are promising candidates for further investigation including preclinical studies. less is known about the effect of their intracellular half-lives on the maintenance of antiviral activity. to investigate this question, we developed a novel in vitro antiviral persistence assay. measurement of the antiviral persistence of tenofovir (tfv) and abacavir (cbv) was coupled to measurement of the half-lives of their tfv-dp and cbv-tp anabolites. methods: mt-2 cells or stimulated primary cd4+ t-cells were incubated with graded concentrations of tfv or cbv for 14 h (h); then extracellular drug was removed by washing. cells were further incubated without drug for 0-24 h and then infected with hiv-1 (iiib or bal). p24 was quantified on day 2; inhibition of hiv-1 replication due to intracellular drug persistence (pc50) was determined relative to a standard ec50. decay of intracellular dp/tps in cd4+ t-cells was measured using lc/ms/ms. results: in mt-2 cells, the pc50 value for tfv 12 h after drug removal remained unchanged relative to the ec50 (<3-fold shift) whereas the pc50 for cbv shifted >65-fold, indicating less persistence of cbv. in cd4+ t-cells, the pc50 value for tfv also showed a minimal shift relative to the ec50 (2.4-fold) 24 h after drug removal. cbv showed a much larger relative shift (>243-fold). quantification by lc/ms/ms of intracellular tfv-dp and cbv-tp in cd4+ t-cells in vitro demonstrated that tfv-dp had the longest intracellular half-life of the two drugs (tfv-dp, 21 h versus cbv-tp, 5 h). conclusions: a novel antiviral persistence assay was developed to study the relationship between intracellular nrti halflives and antiviral activity. in both mt-2 cells and primary activated cd4+ t-cells, tfv had the longest persistence of antiviral activity. in cd4+ t-cells, tfv-dp also had the longest half-life of the two nrtis. cbv-tp had a much shorter half-life than tfv-dp and showed less antiviral persistence. although both drugs are approved for qd dosing, the half-life of intracellular tfv-dp maintains antiviral suppression in vitro over a timeframe most consistent with qd dosing. karen m. watson, tracy l. hartman, lu yang, robert w. buckheit jr. imquest biosciences, inc., frederick, md, usa isis 5320 is a phosphorothioate oligonucleotide with a molecular structure of t2g4t2. the g-quartet possessing molecule has been shown to be a potent inhibitor of hiv attachment and cell-cell fusion and acts by specifically interacting at the v3 loop of gp120. mapping studies with monoclonal antibodies targeting epitopes in and around the v3 loop have been used to define the binding site of isis 5320. in vitro, isis 5320 inhibits all laboratory and clinical strains of hiv-1 and hiv-2 tested, including representative subtype viruses, drug resistant viruses (including mdr viruses) and viruses that utilize the cxcr4 and ccr5 chemokine receptors. serial passage of virus in the presence of increasing concentrations of the oligonucleotide did not result in the selection of drug resistant virus strains and combination assays resulted in additive to synergistic interactions with other approved hiv inhibitors. the antiviral and toxicity profiles of isis 5320 resulted in the performance of human clinical trials for the therapeutic use of the oligonucleotide to treat hiv infection. the antiviral properties and mechanism of action of isis 5320 suggest that it may be an excellent anti-hiv topical microbicide. isis 5320 was found to be highly active in a cervical explant model of hiv infection with highly significant inhibition of ccr5-tropic strains of virus. activity was also observed in cell-free and cell-associated virus transmission assays, as well as in cd4-dependent and cd4-independent acute infection inhibition assays. in microbicidal specific combination assays, significant efficacy has been observed with isis 5320 used in combination with other microbicidal compounds. the results of these studies suggest that isis 5320 may represent a new and novel anti-hiv topical microbicide. karen m. watson, tracy l. hartman, lu yang, robert w. buckheit jr. imquest biosciences, inc., frederick, md, usa though a variety of compounds are being developed as anti-hiv topical microbicides, such as polyanionic molecules, surfactants, natural products, peptides, proteins, heterocycles, and virucidal agents, clinical efficacy studies that demonstrate the ability of these agents to impact virus transmission are still in progress. it has been estimated that a microbicide that is only 60% effective would have the capacity to prevent millions of new infections each year. thus, one of the challenges in hiv drug development is the discovery of compounds that will inhibit the sexual transmission of infectious organisms between sexual partners. the rapid mutability of hiv and the known presence of drug resistant viruses in wild type virus populations suggests that microbicide development will suffer from the same problems that exist for all hiv therapies, namely the selection of resistant virus strains that will bypass the microbicide barrier and infect target cells in the vaginal or rectal environment even in the presence of the microbicide. thus, it is likely that haart-like combination drug therapies will become the most effective means of inhibiting the sexual transmission of hiv. we have evaluated a wide variety of anti-hiv and anti-sti compounds in vitro alone and in combination with one another and have demonstrated that certain patterns of inhibition (additivity, synergy, antagonism) occur between the various classes of compounds. recently, we have compared the combination anti-hiv activity of microbicide compounds in fresh human pbmcs infected with clinical isolates of hiv to the combination activity of the same test agents in cem-ss-based cultures. in general, these two assay systems yield similar combination assay results. to provide a rationale for the combination use of the compounds in a microbicide setting, the same combination of compounds was evaluated in a microbicide-like virus transmission assay. these combination results suggest that higher levels of synergy between virus attachment and reverse transcriptase inhibitors might be expected in the microbicide environment compared to levels predicted for the systemic therapeutic environment. the results of the combination assays with various microbicides will be presented. during the onset of the hiv disease, hiv rna is continually produced in the face of treatment with haart in circulating reservoirs and rt inhibitors are almost ineffective in the postintegration events. among the classes of anti hiv-1 drugs, protease inhibitors (pi) are the unique to inhibit the hiv-1 production in chronically infected macrophages. in the progression of hiv infection, the role of the monocytes-derived macrophages (m/m) is further confirmed as they represent chronologically the first cytotype where the viral replication restarts as a consequence of failure or interruption of antiviral therapy. aim of the work was to evaluate the rebound of hiv-1 production when pi have been removed in hiv-1 chronically infected m/m and, moreover, to verify the effect of this removal on virus maturation, infectivity and ability to trigger apoptosis in uninfected peripheral blood lymphocytes (pbl). a rebound of p24 gag protein was measured starting from 12 h after drug removal yet virus infectivity remained 1 log lower than control up to 1 week. inhibition of hiv-1 replication was still 48% and 18% upon amprenavir 20 and 4 m, respectively. these data were confirmed by western blotting and electronic microscopy showing production and release of immature viral particles. moreover, pi (amprenavir and indinavir) treatment dramatically reduced apoptosis of pbl co-cultured with chronically infected m/m and kept cd4/cd8 ratio above the levels of untreated controls until the 5th day of co-culture. taken altogether, these findings suggest a wide clinical importance for amprenavir and indinavir for their relevant long-lasting antiviral effect in persistently-infected reservoirs of hiv even in case of drug interruption and/or when hiv infection can restart in districts where drugs find not sufficient concentration. moreover, these results strengthen the evidence for an unique positive utilize of pi against ongoing and productive hiv infection. weili jin, salvatore santino, michael wang gilead sciences, foster city, ca, usa background: effective inhibition of hiv reverse transcriptase (rt) currently represents a crucial objective of antiretroviral therapy. capravirine is a second-generation non-nucleoside rt inhibitor (nnrti) that is capable of blocking the replication of certain nnrti-resistant strains of hiv and was recently in clinical development. in this study, we report on the in vitro selection and characterization of viral resistance to capravirine. methods: viral resistance selection experiments were performed in mt-2 cells with the hiv iiib isolate and increasing concentrations of capravirine. viruses were analyzed genotypically by population sequencing and by single genome sequencing (sgs). recombinant viruses with nnrti mutations were generated from proviral dna clones. phenotypic analyses were performed in mt-2 cells. results: capravirine resistance selections were initiated at 1 nm (ec 50 of 1.5 nm for capravirine). following nine passages in the presence of increasing concentrations of capravirine, the l100i mutation emerged in rt and additional passaging led to v179d and f227c mutations at higher concentrations (100-300 nm). further increases in capravirine concentrations led to the emergence of a l100i + v179d + f227c triple mutant, which confers >1000-fold resistance to capravirine. sgs of mixed viral populations from different passages showed that l100i, v179d and f227c were present on the same genome, with l100i as the primary mutation, and f227c and v179d were acquired sequentially at later passages. through sgs analysis, a l100i + k166r + v179d + f227c quadruple mutation on the same genome was also observed at higher capravirine concentrations (>1000 nm). recombinant viruses carrying these mutations were produced to assess their susceptibilities to capravirine. conclusions: after extensive in vitro passaging of hivinfected cells in the presence of capravirine, neither k103n nor y181c mutations in rt were observed. instead, the l100i mutation was initially acquired, followed by mutations f227c and v179d. addition of the k166r mutation to the triple mutant genome, l100i + v179d + f227c, appears to further enhance hiv resistance to capravirine. oluwafemi olawuyi 1 , adeyemi falegan 2 1 medical microbiology, university college hospital, ibadan, nigeria; 2 dentistry, university college hospital, ibadan, nigeria issue: the percentage of aids/hiv is increasing every year in the third worlds, and this is reinforced by the factor that majority of youth in third worlds do not know his/her hiv status. description: a self developed validated and reliable questionnaire [r = 0.87] was used to collect the data and percentage was used to analyze the data. the population of the study was made up of youth [female and male] in higher institutions, working places, market places and community streets in nigeria, 50,000-sample size, selected through simple random sampling technique. the mean age is 25.5 years old. relative risk [rr] calculated is 3.1, i.e. rr >1, indicating that the factor is the risk factor, and the confidential interval [ci] for rr at 95% significant level is 2.61 < 3.1 < 3.90 from the formula, ci lower limit < rr < ci upper limit. lessons learned: seventy percent of the sample population did know his/her hiv status and had had sexual intercourse in the past before, out which 20% had the unprotected intercourse once or more, 25% had protected sex while 25% were not sure of using protection means. while, 20% have knowledge about own hiv status and had had sexual intercourse before. ten percent have no knowledge about own hiv status and had no sexual intercourse before. conclusion: aids/hiv still remains a killer disease in the third world. however, the lack of knowledge of individual's hiv status remains the only highest risk factor for the spread of the disease in the third worlds. yuichiro habu 2,3 , jacob barnor 1,6 , norio yamamoto 4 , kahoko hashimoto 1,2 , naoko miyano-kurosaki 1,2 , koichi ishikawa 5 , naoki yamamoto 5 , david ofori-adjei 6 , hiroshi takaku 1,2,7 1 department of life and environmental sciences, chiba institute of technology, chiba, japan; 2 high technology research center, chiba institute of technology, chiba, japan; 3 japan foundation of aids prevention; 4 department of molecular virology, bio-response, tokyo medical and dental university, tokyo, japan; 5 aids research center, national institute of infectious disease, tokyo, japan; 6 department of virology, noguchi memorial institute for medical research accra-ghana, accra, ghana; 7 bach tech corp. rna interference (rnai) is a potentially strong gene interference tool, which had been successfully used to silence many pathogenic viruses including hiv. however, many recent reports have shown that, in long-term assay cultures involving rna viruses such as hiv, escape mutants breakthrough the silencing effect. in the light of this conundrum, it had been proposed that, vector designed to target multiple genes in a synergistic manner, may address the problem. hence, we designed a chimeric rna expression vector which express vif shrna and decoy tar rna by combining vif shrna and decoy tar rna with linker to which dicer was able to recognize for cleavage, as a second generation rnai expression vector system. the synergistic effect of these molecules enhanced the inhibition of hiv-1 replication in a long-term transduced pbmcs, h9, and jurkat cell culture assays (9 weeks) and prevented virus breakthrough associated with sirna-mediated escape variants. notably, hiv-1 replication was similarly suppressed in the control cells expressing only vif shrna for about 3 weeks, but an increase in virus replication was observed afterwards. hiv viral rna extracted and sequenced at this point indicated escape mutants in the cells expressing the vif target in hiv. we confirmed substitution of bases in the vif shrna target sequence. on the other hand, the incidence of mutation was not observed in a sequence of viral rna from the culture expressing the vif shrna-decoy tar rna at the fourth week. interestingly, virus production was inhibited for a long-term by an effect of decoy tar rna, through the rna-protein interaction. combining shrna with decoy tar rna as second-generation anti-hiv shrna may provide practical basis for applying sirna-based gene therapy to the treatment of hiv/aids. introduction: this is a designed efficient gene therapy against aids/hiv. the novelty of this aids vaccine design/concept is seen in the fact that the 'pol' gene encoding for nonstructural proteins (polyproteins that generate three enzymes: reverse transcriptase, integrase and protease) is cloned in a suitable retroviral vector and adult stem cells are transfected by this and reinfused into the circulation to effectively counter hiv replication and antigenic variation. method: the mrna are isolated from adult stem cells and transcribed into cdna with reverse transcriptase. the cdna are then cloned in a suitable retroviral vector (vacinia) carrying 'pol' gene that confers resistance to a strong reverse transcriptase inhibitor drug. the adult stem cells are transfected by the recombinant mixture, and reinfused into the circulation of hiv infected person. result: the transfected stem cells are reinfused to provide renewable source of more and better empowered normal blood cell types that would disrupt and half hiv replication in the circulation. there would be efficient induction of both humeral and cellular mediated immunity with prolonged expression of antigens and protective immunologic memory generation against hiv antigenic variation. conclusions: this aids vaccine design would lead to both efficient prophylactic and therapeutic therapy against aids in that it would effectively take care of the problematic factor of hiv antigenic variation which has long been the main obstacle to potent aids vaccine development. because of the real risk of interspecies transmission and/or reassortment between avian, swine and human influenza a strains, drug susceptibility monitoring of circulating avian and porzine virus strains appears to be warranted for effective application of antiviral drugs like amantadine. this study was designed to gain insight into amantadine susceptibility of 6 avian and 12 porcine influenza a viruses isolated in germany between 1981 and 2002. virus strains were isolated in embryonated chicken eggs and passaged one time in mdck cells. plaque reduction assays were applied to examine virus susceptibility to amantadine. genotyping was used to confirm drug resistance. in the result of these antiviral studies, only 3 of the 12 porzine isolates but all 6 avian isolates were shown to be amantadine-susceptible. interestingly, the three amantadinesensitive porzine strains were isolated between 1981 and 1987. all porzine influenza a viruses isolated later on were drugresistant and contained the aa substitutions g16e, s31n, and r77q in the matrix protein 2 (m2). additionally, l27a was detected in two h1n1 strains. s31n and/or l27a are well known amino acid substitutions in m2 that confer amantadine resistance. the role of the pig as an intermediate host of avian and human influenza a viruses, the possible involvement of genetic reassortment, and the high incidence of naturally amantadineresistant porcine influenza a viruses suggest a real risk of emergence of amantadine resistant human viruses. therefore, further studies are ongoing now to evaluate the circulation of the resistant phenotype in pigs, birds and human. recently much attention has been devoted to searching for effective chemotherapeutic agents and vaccines for eradication of this notorious disease. at present only chemotherapy is available to combat avian flu, for instance, tamiflu, approved for the treatment by the us-fda. development of a simple, novel molecule with potential antiviral activity against is essential to treat avian flu viral infection. isatin (2,3-dioxoindole), is a versatile lead molecule for designing of potential antiviral agents and its derivatives were reported to possess broad spectrum antiviral activity. methisazone (nmethylisatin-3-thiosemicarbazone) was first clinically approved for treatment of pox viral infections, and its derivatives were documented to have anti-influenza activity. based upon this evidence, the present work was initiated to determine the antiviral activity of novel isatin derivatives against avian flu (h5n1) in mdck cells. antiviral activity was studied by virus yield assay (ec90), and cytotoxicity by neutral red uptake assay by uninfected mdck cells. all five compounds of a series inhibited the replication of avian flu (h5n1) virus replication in mdck cells and compounds spiii-5h and spiii-5cl were most active (ec90 5.5 g/ml, cc50 >100 g/ml and si > 18). details of these studies and results of treatment of influenza-infected mice are discussed. acknowledgement: supported in part by contract noi-ai-15433 and noi-ai-30048 from virology branch, niaid, nih]. arginine-rich peptide conjugated phophorodiamidate morpholino oligomers (arp-pmo) are nuclease resistant antisense compounds that hybridize to target rna in a sequence-specific manner resulting in disrupted rna function. eight arp-pmo were designed to base-pair with various regions of a/pr/8/34 (h1n1) rna and were then evaluated by hemagglutination and plaque assays for their ability to inhibit fluav production in vero cell culture. arp-pmo targeting the aug translation start site of the np or pb1 segment mrnas, or the 3 -terminus of their respective vrnas, were highly effective, reducing influenza virus titer by 1-3 orders of magnitude in a dose-dependent and sequence-specific manner over a period of 2 days. two of the p-pmo, targeting the pb1 translation start site region (pb1-aug) and the 3 terminus of np vrna (np v3 ), were evaluated by endpoint dilution (tcid50) or elisa assays against another h1n1 strain (a/wsn/33), as well as a/memphis/8/88 (h3n2) and a/thailand/1(kan-1)/04 (h5n1). the pb1-aug arp-pmo generated over 85% specific reduction of virus level, regardless of viral subtype or methodology, at concentrations in the range of 10-20 m. the np v3 p-pmo yielded similar results, with the exception of considerably lower efficacy against the h3n2 strain, with which it has two base mispairings. studies are planned to further evaluate of at least two arp-pmos in animal models for h1n1 and h5n1 fluva subtypes. macroheterocyclic compounds containing crown fragments and nitrogen atoms show large-scale biological activity. we synthesized series of aza-crown ethers and their derivatives. we also studied anti-influenza and antiherpetic action of some of them. anti-hsv action of studied compounds was tested using cyto-morphological method. hep-2 cells were infected with hsv-1 strain us in dose 5 ifu/cell. the cells were incubated in eagle's medium that contained compounds in a dose of 10 −4 m in experimental samples, or without them in control samples. then cells were fixed with 96% ethanol and stained with 0.01% acridine orange solution. the amount of infected cells with dna-containing virus inclusion bodies was counted by fluorescent microscopy. anti-hsv activity of compounds was calculated as the difference between of the percentage of infected cells in treated cell cultures to the percentage of infected cells in untreated cell cultures. anti-influenza activity was studied on the model of replication of a/hong kong/1/68 (h3n2) strain in tissue culture of chorio-allantoic membranes of chicken embryos. compounds were used in a dose of 10 −3 m during the study of their anti-influenza action. diaza-18crown-6 and two of its derivatives have showmen neither anti-hsv nor anti-influenza activity. diaza-18crown-6 derivatives that contain 2-oxyethyl-or ethoxycarbonyl-fragments decreased amount of cells infected by hsv-1 by 13 and 29%, respectively. both of these compounds inhibited replication of influenza virus on 1.7 log 10 tid 50 aza-15crown-5 did not show antiviral activity, but both its derivatives proved to be active inhibitors of hsv and influenza virus reproduction. aza-15crown-5 derivatives that contain 2-amino-3-phenyl-propanoyl-or 5-benzyloxy-3-oxapentyl-fragments decreased amount of cells infected by hsv-1 with virus-specific intranuclear inclusions by 41 and 47%, respectively. first compound inhibited replication of influenza virus on 1.5 log 10 tid 50 and the second one decreased virus amount on 2.0 log 10 tid 50 . the results of this study show that aza-crown ethers are the perspective class of compounds for search of new antiviral agents. acknowledgement: this work was partially supported by stcu (grant # 3147) . robert w. sidwell 1 , kevin w. bailey 1 , min-hui wong 1 , donald f. smee 1 , dale l. barnard 1 , shanta bantia 2 1 institute for antiviral research, utah state university, logan, ut, usa; 2 biocryst pharmaceuticals, inc., birmingham, al, usa the cyclopentane neuraminidase inhibitor, peramivir (bcx-1812, rwj-270201) has striking inhibitory effects on a spectrum of influenza viruses in vitro, and has also demonstrated significant effects against influenza a (h1n1, h3n2) and b virus infections when administered orally to mice and ferrets. unfortunately, clinical trials with the drug administered orally were not successful, probably due to low blood levels obtained after oral administration. significant plasma drug levels of peramivir persist up to 6 h after intramuscular (i.m.) injection; more importantly, however, is the observation that peramivir remains tightly bound to influenza virus n9 neuraminidase for over 24 h, suggesting single i.m. or intravenous (i.v.) therapy with the drug may be highly effective against an influenza infection. experiments now in press have indicated that single i.m. peramivir therapy administered up to 48 h after virus exposure was protective to mice infected with influenza a (h1n1) virus. in the present study, peramivir was administered i.m. or i.v. in a single injection 1 h pre-virus exposure in separate experiments to mice infected with an influenza a (h5n1) virus; efficacy was compared to similar dosages of oseltamivir and oseltamivir carboxylate run in parallel. dosages of 20 and 10 mg/kg of peramivir administered by either route significantly prevented deaths, lessened arterial oxygen (sao 2 ) decline, inhibited development of lung consolidation, and inhibited lung virus titers. the lung assays were performed at varying times after virus exposure. oseltamivir and oseltamivir carboxylate, which do not have the same neuraminidase binding abilities seen with peramivir, were less efficacious in these experiments. delaying the single i.v. therapy up to 72 h after virus exposure also significantly inhibited the virus infection. peramivir appeared to be well tolerated in toxicity control animals run concomitantly with these studies. these data indicate parenterally administered peramivir may hold promise as a therapy for clinical influenza a (h5n1) virus infections. acknowledgement: supported by contract no1-ai-15435 from the virology branch, niaid, nih. hiroshi saitoh 1 , naoko miyano-kurosaki 1,2 , hiroshi takaku 1,2 1 department of life and environmental sciences, faculty of engineering, chiba institute of technology, chiba, japan; 2 department of life and environmental sciences, faculty of engineering and high technology research center, chiba institute of technology, chiba, japan background: influenza virus causes widespread infection in the human respiratory tract, but existing vaccines and drug therapy are of limited value. recently, small interfering rnas (sirnas) are a powerful tool for sequence-specific, post-transcriptional gene silencing and have a potential therapeutic and prophylactic application against cancer, as well as infectious diseases. here we show that short interfering rnas (sirnas) specific for conserved regions of the viral genome can potently inhibit influenza virus production in cell lines. the influenza virus np gene is a potential target for rnai technology. on the other hand, the baculovirus (acmnpv) can infect a variety of mammalian cells, facilitating its use as a virus vector for gene delivery in viral entry into cells. in this study, we describe the inhibition of influenza virus production by baculovirus-mediated shrna expression vectors. methods: the psv2neo-u6 plasmid vectors and pvl1393based baculovirus vectors were used in this study. the influenza virus a and b np genes were made into the target and the shrna expression plasmid vectors were constructed under the control of the human u6 pol iii promoter. the shrna expression plasmids or shrna expression baculovirus vectors introduced into mdck cells, and 24 h later the cells were infected with either a/pr8 or b/ibaraki virus at a moi of 0.01. at 72 h postinfection, culture supernatants were harvested and assayed to determine the virus titer by plaque assay. conclusion: the findings reveal that newly synthesized np proteins are required for influenza virus replication and provide a basis for the development of shrnas expression plasmids as prophylaxis and therapy for influenza infection in humans. julia serkedjieva, ekaterina krumova, tsvetanka stefanova, nadja nikolova, maria angelova institute of microbiology, bulgarian academy of sciences, sofia, bulgaria a semi-standardized polyphenol-rich extract (pre), obtained from geranium sanguineum l., inhibited the reproduction of influenza viruses types a and b in vitro and in ovo and protected mice from mortality in the experimental influenza virus infection (serkedjieva and manolova, 1992) . the selective in vitro virus-inhibitory activity of pre was fairly modest and this was in contrast with the significant protection in vivo. thus, the therapeutic effect of pre needed explanation. it was presumed that it might be attributed to a combination of more than one biological activities known for natural polyphenols. we have demonstrated previously that pre manifested strong antioxidant and radical-scavenging activities in model systems (sokmen et al., 2004) . the current study was undertaken to investigate the effect of the plant extract on the levels of the antioxidant enzymes superoxide dismutase (sod), catalase (kt) and peroxidase (po) in mice lungs during influenza virus infection as well as the effect of pre on the production of reactive oxygen species (ros) and reactive nitrogen intermediates (rni) by alveolar macrophages in influenza virus infected mice. mice were challenged intranasally (i.n.) with 5-10 ld 50 of a/aichi/2/68 (h3n2) influenza virus. pre was administered by i.n. instillation 3 h before infection in the dose of 10 mg/kg. it was established that influenza infection induced an increase in sod, kt and po production and on days 6 and 9 after infection their levels reached 140-160% of placebo control. the application of pre brought enzymes values to control levels. influenza infection caused also a significant increase of h 2 o 2 , o 2 •− and no production by alveolar macrophages; the generation of ros and rni peaked on day 9. pre-treatment before viral challenge reduced this excessive production. in conclusion, the obtained results outlined the antioxidant and radical scavenging properties of the plant extract; pre beneficially modulated the oxidative stress response in influenza virus-induced pneumonia. this alternative mechanism of action might contribute to the overall protective effect in the lethal murine experimental influenza infection. the antiviral activity of s11, a natural herb extract, ji-sun kwon 1 , hyun-jeong lee 1 , chi-ung moon 2 , jong-hwan kwak 3 , youn-jeong lee 4 , chang-seon song 1 1 avian disease laboratory, college of veterinary medicine, konkuk university, seoul, korea; 2 hanyang university, seoul, korea; 3 sungkyunkwan university, seoul, korea; 4 national veterinary research and quarantine services, seoul, korea the antiviral activity of s11, one of the traditional korean medical herb extract, against influenza virus was investigated. the 50% effective concentration (ec50) using plaque reduction assay was 31.25 ug/ml and the mean 50% cytotoxic concentration (cc50) using wst-1 assay in the mdck cells was 334 ug/ml. oral gavage treatment of the s11 to balb/c mice infected with a/pr/8/34 (h1n1) influenza virus showed the therapeutic effects as delaying clinical signs, significant inhibition of death and reduction of lung virus titers. to identify the lead molecules, the s11 was subjected to further fractionation, purification, and isolation of active compounds. the antiviral activity of these natural herb compounds will be discussed. these results suggest that the s11 is a possible candidate for the development of new antiviral medicine for influenza therapy. hiroshi takaku 1,2,4 , takayuki abe 3 , hitoshi takahashi 1 , naoko miyano-kurosaki 1,2 1 department life environ. sci., chiba inst. tech., chiba, japan; 2 high tech. res. center, chiba inst. tech., chiba, japan; 3 res. inst. microbial dis., osaka university, osaka, japan; 4 bach tech corp background: the baculovirus autographa californica nuclear polyhedrosis virus (acnpv) has long been used as a biopesticide and as a tool for an efficient recombinant protein production in insect cells. in this study, we examined the immunization of a recombinant baculovirus expressing the influenza virus hemagglutinin (ha) against lethal influenza infection in mice. protection was observed in mice immunized intranasally with not only the recombinant baculovirus but also a wild-type baculovirus. baculovirus was also shown to induce secretion of inflammatory cytokines, such as tnf-␣ and il-6, in murine raw 264.7 macrophage cell line. results: a varied route of immunization with a recombinant baculovirus expressing the influenza virus hemagglutinin protein of a/pr/8/34 (h1n1) virus against lethal influenza infection was examined in mice. the recombinant baculovirus encoding the hemagglutinin gene under the control of chicken ␤ actin promoter was inoculated twice, 2 weeks apart, at a dose of 1.1 × 10 8 pfu per mouse by intramuscular, intradermal, intraperitoneal, and intranasal routes. mice intramuscularly and intraperitoneally immunized with the recombinant exhibited higher level of production of serum anti ha antibody than those immunized via the other routes, but protection was only achieved by the intranasal immunization. surprisingly, mice immunized with a wild-type baculovirus with intranasal route were also protected from the lethal influenza virus challenge. sufficient protection in mice was achieved by the intranasal immunizations with 10 8 pfu of either the recombinant or wild-type baculovirus, as evaluated by the reduction of virus titer, production of inflammatory cytokines, and pulmonary consolidations in the lung. these results indicate that infection with a baculovirus induces a strong innate immune response and protection of mice from lethal influenza virus infection. conclusion: baculovirus (cpg motifs) induces a strong innate immune response and protection of mice from lethal influenza virus a and b infection. andrew vaillant 1 , annie lebel 2 , nathalie goyette 2 , guy boivin 2 , jean-marc juteau 1 , phil wyde 3 1 replicor inc., laval, que., canada; 2 chuq-chul and laval university, st. foy, que., canada; 3 baylor college of medicine, university of texas, houston, tx, usa potent antiviral activity of phosphorothioate oligonucleotides (ps-ons) was observed against influenza viral infections. antiviral activity was sequence-independent, size dependent (optimally active ps-ons were ≥40 bases in length) and dependent on the presence of the phosphorothioate modification (hydrophobicity). binding studies showed that rep 9 (a 40 mer degenerate ps-on) interacts with both neuraminidase and hemagglutinin although the sialidase activity of neuraminidase was not affected, suggesting that the structural interactions of these proteins required for influenza activity are the target for this compound. the requirement for hydrophobicity further suggests that the alpha helical regions of hemagglutinin are one of the regions of interaction. the antiviral activity of rep 9 was conserved in many influenza a and b strains suggesting potential therapeutic activity against avian flu and other newly emerging influenza strains. rep 9 aerosol has excellent characteristics for lung deposition and aerosol treatment with rep 9 was well tolerated and highly effective against infections with influenza a both in prophylaxis and 24 h after infection. these results demonstrate the therapeutic potential of aerosolized ps-ons against influenza infection. acknowledgement: supported by nih contract no1-ai-15437. irina v. alymova 1 , y. sudhakara babu 2 , allen portner 1 1 virology division, department of infectious diseases, st. jude children's research hospital, memphis, tn 38105, usa; 2 biocryst pharmaceutical, inc., birmingham, al 35244, usa bcx 2798 is a novel selective inhibitor of human parainfluenza virus infections, which design was based on the threedimensional structure of the hemagglutinin-neuraminidase (hn) protein of newcastle disease virus. compound exhibited striking activity against parainfluenza viruses in vitro and in vivo, and was efficacious in prophylaxis of lethal synergism between parainfluenza virus and streptococcus pneumoniae in a mouse model. present study was conducted to determine if bcx 2798's resistant variants of the recombinant sendai virus whose hn gene was replaced with that of human parainfluenza virus type 1 (rsev(hpiv-1 hn) could be selected in tissue culture and animals. for this purpose virus was serially passaged in llc-mk 2 cells at moi 0.1 in the presence of increasing (from 100 to 3200 m) concentrations of compound; infected 129×1/svj mice were treated with 10 mg/kg/day of bcx 2798 twice for five days. treatment started 4 h before infection. individual clones of viruses were analyzed for the presence of mutations. one mutation, e527k, on the globular head region of the hn protein was selected in tissue culture after the fifth and eleventh passages of rsev (hpiv-1 hn) . several mutations in hn gene of rsev (hpiv-1 hn) were selected in an animal model after the second passage of virus from mice treated with bcx 2798. two mutations, n23s and p29q, were located in the cytoplasmic domain of hn protein; mutations n173s and t553a were found on the globular head region of the glycoprotein. only nonconserved amino-acid residues of hn protein were involved in substitutions. all isolated mutant viruses were stable after the five passages in llc-mk 2 cells without drug; did not develop other substitutions in the presence of drug and displayed no resistance to bcx 2798 both in vitro and in vivo. infectivity of all mutants was not altered to compare with the wild type of rsev (hpiv-1 hn) virus. taking together our results indicate that prophylaxis/treatment of human parainfluenza virus infections with bcx 2798 may not lead to appearance of clinically significant variant of viruses. kie-hoon jung 1 , michelle mendenhall 1 , lawrence m. blatt 2 , robert w. sidwell 1 , brian b. gowen 1 1 institute for antiviral research, utah state university, logan, ut, usa; 2 intermune, brisbane, ca, usa hantavirus pulmonary syndrome (hps) is an acute human respiratory disease with remarkably high case fatality rates (30-50%) for which the etiological agents are members of the bunyaviridae family, genus hantavirus. maporal (map) virus is a recently identified hantavirus isolated in western venezuela, which is most similar phylogenetically to hantaviruses known to cause hps in southern regions of south america. despite the lack of evidence that map can productively infect humans and cause hps, infection of hamsters closely resembles disease manifestations associated with human hps. hantaviruses, in general, are known to produce little to no cytopathic effect (cpe) in cultured cell lines. unexpectedly, we found that map produces remarkable cpe in several vero cell lines facilitating the evaluation of known antiviral agents, ribavirin and interferon alfacon-1. both drugs were highly effective at reducing cpe, as determined by visual examination and neutral red dye uptake, associated with map infection. since much of the observed cpe may be due to apoptosis of uninfected bystander cells, we also developed a quantitative (q)rt-pcr assay to detect copies of map genomic sequence to more directly assess the inhibition of viral replication. data obtained using the qrt-pcr-based assay were consistent with the visual cpe reduction and neutral red-uptake cytotoxicity findings. the development of in vitro antiviral testing methods for map are essential to the evolution of the in vivo hamster disease model of hps. the latter is of utmost importance considering the current need for effective antivirals for the treatment of hps and the lack of a suitable model that does not require biosafety level 4 containment facilities. acknowledgement: supported by contract no1-ai-30048 from the virology branch, national institute of allergy and infectious diseases, national institutes of health. nucleoside analogues are widely used in antiviral and anticancer chemotherapy. for this class of drugs, intracellular conversion of the nucleoside analogue into the corresponding 5mono-, 5 -di-, and 5 -triphosphate after target cell penetration is a prerequisite for biological activity. because of the structural differences from natural nucleosides, this conversion is often inefficient and, as a consequence, therapeutic efficacy is sometimes limited. the free phosphates, or nucleotides, have limited utility in therapy on account of their poor membrane permeability and chemical stability. one approach to improve the therapeutic potential of nucleoside analogues is the delivery of the corresponding nucleotide entities via neutral, lipophilic prodrugs, or protides. the nucleoside aryl phosphoramidate approach, developed by mcguigan and co-workers (2004) has been successfully applied to a number of different nucleosides (azt, d4t, dda, d4a). the general structure of aryl phosphoramidates encompasses two masking groups, an amino acid ester and an aryl moiety bonded to the phosphate group. in order to apply this protide technology to nucleosides with the potential for anti-hepatitis c virus (hcv) activity, we have undertaken studies designed to probe the effect of varying the natural and unnatural amino acid esters and the aryl groups used as masking groups in the target phosphoramidates. these compounds have been synthesised and evaluated using genotipe 1b sub-genomic hcv replicon. we have prepared a variety of arylphosphoramidate derivatives from a range of 4 -substituted nucleosides, including 4azido-cytidine, 4 -azido-uridine, and 2 ,3 -protected variants. with certain nucleoside phophoramidates, we have observed dramatic enhancement (>1000-fold) of replicon activity relative to the parent nucleoside. the synthesis, biological activity and sar of these compounds will be presented. reference mcguigan, d. cahard, balzarini, j., 2004. mini-review. med. chem. 4, 371-382 . we have identified a series of novel anthranilic acid derivatives that are potent, reversible inhibitors of hepatitis c virus (hcv) ns5b polymerase, an essential enzyme for viral replication. the micromolar ns5b polymerase inhibitors belong to the n-phenoxyacetylanthranilic acid chemotype. x-ray crystallography determined that the inhibitors bound to ns5b between the thumb and palm regions adjacent to the active site. guided by crystallography, subsequent modifications to the hydrogen bonding and lipophilic regions of the inhibitors resulted in greatly improved activity against ns5b. further sar studies revealed a second, more potent sub-series where the phenoxy group was replaced by an anilino group. analogs in both subseries showed antiviral activity in a cell-based replicon model of hcv. andrea brancale 1 , dimitrios vlachakis 1 , maria chiara barbera 1 , romano silvestri 2 , colin berry 3 , johan neyts 4 1 cardiff university, the welsh school of pharmacy, cardiff cf10 3 xf, uk; 2 universita' degli studi "la sapienza", dipartimento di studi farmaceutici, 00185 roma, italy; 3 cardiff university, cardiff school of biosciences, cardiff cf10 3us, uk; 4 rega institute for medical research, k.u. leuven, b 300 leuven, belgium hepatitis c is a viral infection that affects 170 million people worldwide, including 4 million in the united states and 8 million in europe. the virus establishes a chronic infection in 55-85% of cases and 20% of affected individuals develop cirrhosis. at the moment there is neither a vaccine nor an effective antiviral therapy available and efforts to identify a specific anti-hcv inhibitor have dramatically intensified in the last few years. many research groups have focused their interest on the enzymes involved in the viral replication and, among these enzyme, the viral helicase/ntpase has proven to be a suitable target for developing novel anti-hcv compounds. compound 1 is a potent inhibitor of the hcv helicase and, although its mode of action is still uncertain, it has been proposed that it acts as competitive inhibitor of rna binding. starting from this hypothesis, we have prepared a series of novel compounds based on the structure of 1 where the benzimidazole moiety has been replaced by different chemical groups, including the negatively charged carboxylate moiety, which should mimic the phosphate backbone of the nucleic acid. the synthesis, the enzyme inhibition and the biological evaluation in replicon of these novel compounds will be presented and analyzed. dale r. cameron migenix inc., 3650 wesbrook mall, vancouver, bc, canada v6s 2l2 hepatitis c virus (hcv), a leading cause of liver disease, continues to be an attractive target for new drug development. among the more favourable approaches to developing new hcv drugs is to target the rna-dependant rna (rdr) polymerase (ns5b), which has been shown to be an essential enzyme for replication. there are several published non-nucleoside inhibitors of this polymerase (some in clinical development) and several published allosteric binding pockets on the protein they target. to be successful, traditional lead identification can be timeintensive, costly and have large infrastructure requirements. increasingly, a push towards effective computational-based screening has led to the development of virtual screening tools. such tools allow investigation of large quantities of compounds in silico for particular properties without the need for compound synthesis or high throughput screening. moreover, these techniques require only a modest infrastructure investment and are very efficient. we employed the openeye set of screening tools (omega, rocs and eon) in concert with publicly available hcv inhibitor information, and commercial databases to identify novel leads. the inhibitor coordinates from a protein-inhibitor complex crystal structure were utilized as the target. available compound databases (asinex and chembridge) were utilized as the testset of compounds. filtered compound conformers were generated using omega and compared with the template using rocs with post-analysis by eon. visual analysis to maximize particular desirable binding features while minimizing protein-inhibitor steric clash allowed the list of potential hits to be further narrowed. multiple classes of compound were identified from the above procedure and after sourcing a subset of the actual compounds or close analogs, they were tested for enzymatic inhibition activity and further characterized. iteration of the process resulted in the identification of a lead compound class containing multiple active compounds, one with reasonable replicon activity. in conclusion, readily available structural and database information and virtual screening tools can be successfully utilized to identify novel inhibitors of hcv rdr polymerase which, in turn, can serve as novel leads for developing new therapies for treating hcv. synthesis, antiviral activity, and cytotoxicity of some novel quinazolin-4(3h)-one derivatives a series of novel 6-bromo/6,8-dibromo-4-(4-oxo-2-phenyl-4h-quinazolin-3y-l)-benzenesulphonamides were synthesized by condensation of 2-substituted benzo[1,3]oxazine-4-ones and sulphonamide. their chemical structures were assigned by means of spectral analysis (ft-ir, pmr, ms). synthesized compounds were screened for in vitro antiviral activity against human pathogenic viruses (hiv, hcv, hsv, vv). 6-bromo-4-(4-oxo-2-phenyl-4h-quinazolin-3y-l)benzenesulphonamide (sps-ii) and 4-(4-oxo-2-phenyl-4hquinazolin-3y-l)-benzenesulphonamide (sps-i) inhibits the replication of hiv-1 in acutely infected mt-4 cells at a concentration of approximately 10 g/ml, while not being toxic to the host cell at a concentration of 60 or >125 g/ml (selectivity index: 8 and >12), respectively. in huh 5-2 cells sps-i inhibited hcv rna synthesis at ec50 of 8 g/ml, while at cc50 for cell growth 32 g/ml. sps-ii inhibited the virus-induced cytopathicity in human embryonic lung (hel) cell infection with hsv-1, hsv-2 or vaccinia (vv) at a concentration of 50 g/ml, while not being toxic to the cells up to a concentration of 400 g/ml. further molecular modification in this series of compounds may help in optimising their antiviral activity. wengang yang, yongnian sun, avinash phadke, milind deshpande, mingjun huang achillion pharmaceuticals, new haven, ct 06511, usa hcv nonstructural protein ns5b is the catalytic subunit of the replication complexes, possessing a motif characteristic of rna-dependent rna polymerases. biochemical assays using recombinant ns5b have been used to investigate ns5b nonnucleoside inhibitors. however, the inhibitory effect of compounds often varies with the forms of recombinant ns5b and the concentrations of the template and/or primer used in the assays. in addition, it does not always correlate to that obtained with replicon-containing cells. these observations have cast concerns about the validity of these cell-free assays. in the report, we explored replication complexes, isolated as crude membrane fractions from replicon-containing cells, for their competency to synthesize viral rna in vitro as well as their responsiveness to ns5b inhibitors. after optimizing the experimental conditions, two species of nascent viral rna, one double-stranded and the other single-stranded, were readily detected. the addition of ns5b nucleotide inhibitor blocked synthesis of both species. the presence of nonnucleoside inhibitors, however, inhibited mostly single-stranded rna (ssrna) synthesis. in addition, the replication complexes isolated from the cells containing a replicon that carried a resistant mutation in ns5b to the nonnucleoside inhibitor were able to synthesize the same amount of ssrna in vitro regardless of the presence or absence of the inhibitor, demonstrating that the phenomenon is due to the specific inhibitory effect of the compound on ns5b. combining with kinetic studies that ssrna synthesis was inhibited only when the nonnucleoside inhibitor was present during the pulse period, we conclude that ssrna synthesis catalyzed by the replication complexes in vitro is likely derived from the de novo initiation. we have recently reported the synthesis and antiviral activities of a ring-expanded ("fat") nucleoside analogue, called nz-51, that inhibits both hcv and hiv in vitro with ec 50 values ranging in micromolar concentrations or less, and little or low toxicity to the host cells. in this part ii of the presentation on this subject, we report our preliminary results on mechanistic studies of anti-hcv activity of this compound, along with the synthesis and antiviral activity of a few additional analogues in the series. in light of the fact that hcv is a major co-infection in patients infected with hiv, and that a number of them ultimately die of end-stage hcv-related complications including liver cirrhosis and hepatocellular carcinoma, a drug with dual inhibitory characteristics against both viruses is highly desirable and timely. nigel bourne, ronald veselenak, richard pyles, minkyung yi, stanley lemon the university of texas medical branch, galveston, tx, usa more than 170 million people worldwide are estimated to be infected with hepatitis c virus (hcv). in the majority of these people a chronic infection is established which can result in serious long-term liver damage including progressive fibrosis, cirrhosis and hepatocellular carcinoma. in fact, hcv is believed to cause more than 100,000 cases of liver cancer annually worldwide and accounts for at least 40% of liver transplants in the us. current treatment options are limited and there is a high treatment failure rate. thus, there is a real need for new treatment options. amantadine has been evaluated as a treatment for chronic hcv infection in a number of clinical studies both as a monotherapy and in combination with other therapeutics. however, the results of these trials have been contradictory and at this time the clinical potential of amantadine as a therapy for chronic hcv infection remains unclear. recent studies have shown that the small hydrophobic hcv p7 protein forms an amantadine sensitive ion channel providing a possible basis for antiviral activity. we examined the ability of amantadine to reduce hcv replication in both subgenomic and full-length hcv replicons of genotypes 1a strain h77c and genotype 1b strain n. in these studies amantadine failed to reduce viral rna replication in any of the replicons tested. further, in infectious virus assays using hcv genotype 2a strain jhf-1 10 um amantadine failed to reduce viral rna levels under any of the conditions tested. however, in these infectious virus studies, when the viral inoculum was treated with amantadine prior to infection of cell monolayers, or when the amantadine was added to cells 1 h after virus adsorption there was a significant reduction in the number of infectious viral foci observed after 72 h incubation (p < 0.05 and <0.01, respectively). these results suggest that even in the absence of a direct impact on rna replication amantadine has antiviral activity. we are currently evaluating amantadine for activity in infectious hcv genotype 1a assays to further define its antiviral spectrum of activity. studies to more fully define its mechanism of action in the virus life cycle are also underway. dominique dugourd, raymond siu, jeremy fenn migenix inc., vancouver, bc, canada celgosivir is an alpha glucosidase inhibitor that is being developed for the treatment of hepatitis c virus (hcv) infections in humans. the purpose of this study was to evaluate the in vitro antiviral activity of celgosivir and its primary active metabolite, castanospermine, when combined with current approved therapies (ribavirin, interferon ␣-2b, or both) in a surrogate model of hcv (bovine viral diarrhea virus (bvdv)). compounds alone or in combination were tested against bvdv in infected madin-darby bovine kidney (mdbk) cells. synergies were analyzed using isobolograms and volume of synergy measurements (macsynergy ii tm software). the celgosivirinterferon ␣2b combination was significantly more synergistic than the celgosivir-ribavirin combination (∼3-fold), or the ribavirin-interferon ␣2b combination (∼2-fold). similarly, the castanospermine-interferon ␣2b double combination was more synergistic than the castanospermine-ribavirin combination (∼5-fold), or the ribavirin-interferon ␣2b combination (∼3.3-fold). the combinations of celgosivir-interferon ␣2b or castanospermine-interferon ␣2b led to significant decreases in the ec50s of celgosivir (up to >20-fold) and castanospermine (up to >50-fold). the effective ec50s of celgosivir or castanospermine were further reduced by the addition of ribavirin. the cytotoxicity of the double and triple combinations was additive or less than additive, indicating that combinations of celgosivir or castanospermine with ribavirin and/or interferon ␣2b were generally less toxic than expected. these results indicate that the combination of celgosivir with interferon ␣2b or with interferon ␣2b and ribavirin may be effective in the treatment of hcv. pegylated interferon ␣ plus ribavirin is the current standard of care for the treatment of chronic hepatitis c virus (hcv) infections. this regimen results in sustained virologic response in only about 50% of patients and is associated with significant treatment-associated toxicities. a number of approaches are being used to identify novel therapeutic combinations with better tolerability and/or efficacy. inhibitors of endoplasmic reticulum (er) ␣-glucosidase have been shown to inhibit viral replication and secretion and may have utility as part of new multi-drug treatment cocktails. the ␣-glucosidase inhibitor celgosivir is currently being evaluated in combination with pegylated interferon ␣ and ribavirin in humans. the purpose of this study was to evaluate the antiviral effects of combinations of celgosivir and castanospermine, the primary active metabolite of celgosivir, with other antiviral agents having diverse mechanisms of action. the effect of the combination of celgosivir or castanospermine with the nucleoside analogue nm-107, amantadine, and another iminosugar, n-butyl-deoxynojirimycin (nb-dnj) was determined in a cytopathic assay using the hcv surrogate virus bovine viral diarrhea virus in madin darby bovine kidney cells. synergies were analyzed using isobolograms and volume of synergy measurements (macsynergy ii tm software). volumes of synergy indicated that the castanospermine and nb-dnj combination was additive, while the celgosivir and nb-dnj combination was synergistic at high nb-dnj concentrations (>100 m). celgosivir and castanospermine were synergistic with both amantadine and nm-107, with volumes of synergy between 60 and 150 m%. isobologram analysis confirmed these synergistic interactions. these results indicate that celgosivir could be considered in combination regimens containing drugs that directly target viral replication like nm-107. mechanism(s) of synergy are under investigation. department of biotechnology, yonsei university, seoul 120-749, korea hepatitis c virus (hcv) is an enveloped virus with positivestranded rna genome of approximately 9.6 kilobases and a major cause of non-a and non-b hepatitis, leading to liver cirrhosis and hepatocellular carcinoma. combination of interferon-␣ (ifn-␣) and ribavirin is the current standard therapy for the treatment of hcv infection, but there is no specific antiviral therapy available. the hcv viral genome encodes a single polyprotein of approximately 3010 amino acids, which is proteolytically processed by a combination of host and viral proteases into at least 10 distinct structural and nonstructural proteins. the structural proteins include c, e1, e2, and p7 and the nonstructural (ns) proteins include ns2, ns3, ns4a, ns4b, ns5a, and ns5b. as new hcv specific therapies, small-molecule inhibitors against hcv enzymes including ns5b protein, the viral rna-dependent rna polymerase (rdrp), and ns3 protease are in clinical tests. however, rapid emerging of drugresistant mutants has been hampering their practical clinical applications. recently, we have shown that phosphorylation of hcv rna polymerase by protein kinase c-like 2 (prk2) regulates virus rna replication. hcv rna replication was inhibited when prk2 expression level was down-regulated by using a prk2-specific sirna. in this study, we investigated the anti-hcv effect of prk2 inhibitors in an hcv subgenomic replicon system. treatment of the replicon cells with prk2 inhibitors suppressing the endogenous prk2 activity inhibited the phosphorylation of hcv rna polymerase and resulted in suppression of hcv rna replication in a dose-dependent manner. furthermore, the prk2 inhibitor in combination with ifn-␣ more effectively inhibited hcv rna replication than ifn-␣ alone. because the prk2 inhibitor did not show cytotoxicity in the cell-based drug inhibition studies and cellular proteins rarely get mutated, prk2 can serve as a cellular target for therapeutic intervention of hcv replication. specific inactivation of prk2 activity will provide an opportunity to interfere with hcv rna replication. haitao guo 1 , tianlun zhou 2 , ju-tao guo 1 , andrea cuconati 3 , anand mehta 1 , timothy block 1 1 drexel university college of medicine, doylestown, pa, usa; 2 nucleonic inc., irvine, ca, usa; 3 hepatitis b foundation, doylestown, pa, usa more than 400 million people worldwide are chronically infected with hepatitis b virus (hbv). the major complication of chronic hepatitis b is the development of primary hepatocellular carcinoma (hcc), which causes an estimated 500,000 deaths annually. currently clinical treatments (␣-interferon and nucleoside analogs) of chronic hepatitis b rarely cure the virus infection. this is due, at least in part, to their failure to eliminate viral covalently closed circular (ccc) dna from the nuclei of infected hepatocytes. hbv cccdna is essential to the virus life cycle by serving as the template for the transcription of the pregenomic rna and of the subviral rna species. its elimination during chronic infection is considered critical to long-term therapy. however, cccdna has not previously been targeted in high throughput screens of small molecule libraries. to screen compound libraries for antiviral drugs targeting cccdna, we set out to develop a cell-based assay suitable for high throughput screening. since cccdna is time-consuming to assay, it was desirable to use a viral gene product that could serve as a reporter for intracellular cccdna level. we predicted that the secretion of hbv e antigen (hbeag) by hepad38 cells, a hepg2-derived tetracycline inducible hbv expression cell line, would be cccdna-dependent. this is because a large portion of pre-core mrna leader sequence in the 5 terminus of integrated viral genome was deleted, preventing hbeag expression from transgene, but could be restored from the 3 terminal redundancy of pre-genomic rna during viral dna replication and subsequent cccdna formation. our experimental results showed that following induction, hepad38 produced and accumulated cccdna, which became detectable between 7 and 8 days. hbeag synthesis and secretion into culture fluid were dependent upon and proportional to the level of cccdna detected. therefore, the secretion of hbeag by hepad38 cells could potentially serve as a convenient reporter for the high throughput screening of novel antiviral drugs targeting hbv cccdna. kathy aldern, james beadle, karl hostetler university of california, san diego and the veterans medical research foundation, san diego, ca, usa (s)-hpmpa is a broad spectrum antiviral active against orthopoxviruses, hbv, cmv, hsv, and other herpes group viruses. we have shown that hdp-(s)-hpmpa has greatly enhanced antiviral activity against these viruses. in addition, while hpmpa itself is nearly inactive against hiv, we showed that hdp-(s)-hpmpa exhibited an ec50 >3 logs less than unmodified hpmpa in mt-2 cells by p24 reduction assay. to evaluate the metabolic basis for the increased antiviral activity, we studied and compared the cellular uptake of radiolabeled cdv, (s)-hpmpa and their hdp-esters and conversion to hpmpa-diphosphate (hpmpapp) and cdv-diphosphate (cdvpp) in mrc-5 human lung fibroblasts using hplc partisil sax ion exchange chromatography. cellular uptake of hdp-cdv and hdp-(s)-hpmpa was similar. however, when cells were exposed to the respective drugs for 6, 24 and 48 h, hpmpapp appeared much earlier than cdvpp and reached levels several fold greater than observed with hdp-cdv. drug wash out experiments were carried out in mrc-5 cells exposed to radiolabeled hdp-cdv and hdp-(s)-hpmpa. after 24 h, the culture medium was removed and replaced with complete medium without drug and the levels of hpmpapp and cdvpp were measured by hplc every 2 days for 0-10 days. levels of the diphosphates declined slowly with a t 1/2 of 5-10 days. in conclusion, hdp-(s)-hpmpa is converted to its diphosphate more rapidly than hdp-cdv and reaches higher intracellular levels. this may explain, in part, its greater antiviral activity. the antiviral activity and oral bioavailability of cidofovir (cdv) is enhanced when the phosphonate is esterified with various straight chain alkoxyalkyl groups. the length of this chain is an important determinant of antiviral activity and selectivity. however, in some cases, rapid metabolism to an inactive short chain metabolite was observed. to enhance the metabolic stability of these esters, we synthesized cidofovir alkoxyalkyl esters bearing methyl groups on the penultimate carbon of the alkyl chain. enzymatic stability of 15-me-hdp-cdv (1) was tested in liver s9 fractions from various species. in mouse and human liver s9 fractions, compound 1 was completely stable for 90 min while 15-20% of the straight chain hdp-cdv was metabolized. the branched alkoxyalkyl esters were then evaluated in cells infected with vaccinia, cowpox and ectromelia viruses. the branched methyl analogs were substantially more active than cdv and equal to or slightly more active than the straight chain analogs. compound 1 retained full activity compared to hdp-cdv and compound 2 showed greater activity against orthopoxviruses compared to its unbranched analog. we believe that the structural modification of the alkyl chain slows the formation of inactive metabolites, possibly by interfering with oxidation and may result in better pharmacokinetics and more potent antiviral activity against orthopoxvirus infection in vivo. cidofovir ([1-(s)-3-hydroxy-2-(phosphonomethoxy)propyl]cytosine, hpmpc) is a broad spectrum antiviral agent clinically used for treatment of aids-related cmv retinitis. cidofovir has limited oral bioavailability (<5%), attributed to ionization of its phosphonic diacid moiety under physiological conditions. we have shown that masking of this group by conjugation of the cyclic form of the drug (chpmpc) via a ser side chain p-o ester linkage with x-ser dipeptides, where x = a hydrophobic amino acid, can result in prodrugs 1 that afford significantly improved biological availability of parent drug in an animal model. here we describe the total synthesis of novel cyclic cidofovir prodrugs 2ab of l-val and l-phe using an alternative conjugation strategy, viz. via an ethylene glycol link utilizing p-o and c-o ester bonds. the preparation of the hpmpc synthon from r-glycidol used our modification of the literature procedure (brodfuehrer et al., 1994) , involving reaction of tritylated (r)-glycidol directly with unprotected cytosine to achieve regiospecific opening of the epoxide ring, followed by reaction with benzoic acid anhydride to obtain the desired n-benzoyl intermediate needed to continue the synthesis. pybop was used as condensing agent in a convenient, one-pot conversion of hpmpc to chpmpc and subsequent esterfication of the latter by the ethylene glycol-modified amino acids. the prodrugs 2 were converted to drug by cellular (caco-2, hff) and tissue (liver and intestinal) homogenates, but did not show enhanced oral bioavailability when evaluated in a rat model, suggesting that such compounds may be useful for understanding the effectiveness of 1 in drug delivery. cidofovir (cdv) is a broad-spectrum anti-viral agent that is used to treat aids-related cytomegalovirus (cmv) retinitis and other cmv infections. cdv has good in vitro activity against orthopox viruses, including smallpox; however, its use is limited because of the drug's low oral bioavailability and poor transport into cells. in order to improve its oral bioavailability, our group has synthesized a series of dipeptide and amino acid prodrugs of the cyclic analog of cidofovir (ccdv). in the current project, we examined the cytotoxicity and antiviral activity of the prodrugs, showing that the compounds are not cytotoxic and have diverse activity against hcmv and orthopox viruses (vaccinia and cow pox) with 50% inhibitory concentrations ranging from 0.1 to 0.5 and 10 m and greater, respectively for the two virus types. in vitro and in situ perfusion studies established that the permeability of the prodrugs is enhanced more than 30-fold and that the transport is mediated, at least in part, by the intestinal dipeptide transporter. we also have found that the bioavailability of the prodrugs is dependent upon the prodrug structure and that we can achieve up to an eight-fold increase in bioavailability over the parent compound in vivo. drug stability experiments showed that in gastrointestinal and liver homogenates, the ccdv prodrugs are enzymatically hydrolyzed to the parent compound. it is clear from this work that the biologically benign dipeptide moiety, strategically linked to the drug to mask its anionic properties, significantly enhances intestinal transport of ccdv, creating the possibility of an orally bioavailable form of ccdv with low toxicity. acknowledgement: supported by funds from tsrl inc, the university of michigan, and nih grants r43ai056864 and u01ai061457. lawrence trost 1 , bernhard lampert 1 , lloyd frick 2 , merrick almond 1 , george painter 1 1 chimerix, inc., durham, nc, usa; 2 dmpk advisor, chimerix, inc., durham, nc, usa foscarnet, a pyrophosphate analog approved for the treatment of cmv retinitis and acyclovir-resistant herpes infections in immunocompromised patients, is active against highly drug resistant strains of hiv-1. however, the clinical utility of foscarnet is limited because it requires controlled intravenous infusion and is associated with high risks of renal impairment and seizure caused by alterations in plasma minerals and electrolytes. lipid conjugation has been shown to increase the in vitro activity, improve oral bioavailability, and reduce the toxicity of several antiviral drugs requiring intravenous administration because of poor bioavailability. in the case of foscarnet, conjugation to methylbatyl alcohol (cmx012) decreases the apparent ec 50 value against hiv-1 by up to 40-fold. cmx012 was esterified to produce cmx052 in order to increase solubility and to protect against decarboxylation of the foscarnet moiety during passage through the stomach. here we present the results of a preliminary toxicology and toxicokinetic study of the methylbatyl alcohol conjugate of foscarnet methyl ester (cmx052). rats were given oral doses of 10, 30 and 100 mg/kg cmx052 daily for 7 days. there were no clinical signs of toxicity. body weight and food consumption were comparable to controls and serum biochemistry, hematology, coagulation parameters and urinalysis were normal. there were no gross findings at necropsy, no effects on organ weights and no findings by histopathological examination of a wide range of tissues. importantly, there were no changes in serum biochemistry parameters or histopathological examination that were indicative of the renal impairment or serum electrolyte changes that are associated with foscarnet. oral dosing resulted in significant plasma exposure to cmx012 (c max > 4 g/ml), the biologically active deesterified form of cmx052. in conclusion, cmx052 is absorbed after oral administration, converted to cmx012, and has a good preliminary toxicity profile. these results support the development of cmx052 for the treatment of drug resistant hiv infection. zhiqian wu 1 , julie breitenbach 2 , ulrika erickson 1 , john hilfinger 3 , john drach 2 , gordon amidon 1 1 department of pharmaceutical sciences, college of pharmacy, the university of michigan, ann arbor, mi, usa; 2 school of dentistry, the university of michigan, ann arbor, mi, usa; 3 tsrl, inc., ann arbor, mi, usa vaccinia virus is a surrogate model system for study of pox virology and development of antiviral therapeutics. the potent anti vaccinia virus activity and various shortcomings of vidarabine make it a good candidate for improvement by utilizing prodrug strategy. vidarabine is a polar nucleoside drug with low membrane permeability and rapid degradation by adonesine deaminase. 5 -monoester prodrugs of vidarabine with various amino acids promoieties (l-valine, l-isoleucine, l-phenylalanine. laspartic acid, l-proline) are synthesized and evaluated for their stability, permeability and activity against vaccinia virus. prodrugs exhibit different hydrolysis rate in caco-2 cell homogenate (t1/2: 2-40 min). 5 -l-isoleucyl and 5 -l-valyl monoester prodrugs exhibit comparable bio-conversion rate and hpept1mediated uptake as well as caco-2 permeability with valacyclovir, a commercially marketed oral amino acid ester prodrug. both prodrugs have potent activity against vaccinia virus and are resistant to ada1. preliminary animal study shows 5 -lisoleucyl vidarabine results in >10-fold increase in circulating vidarabine level. the results suggest that it may be possible to use amino acids prodrug strategy to improve vidarabine as anti vaccinia virus agent. vidarabine [9-␤-d-arabinofuranosyl)adenine or ara-a) was originally investigated as an anti-tumor agent and was later found to be active against herpes simplex virus (hsv) types 1 and 2. it was the first fda-approved drug for treatment of systemic hsv infections. although replaced by acyclovir and analogs for most applications, vidarabine remains an alternative therapy for acyclovir-resistant hsv and varicella-zoster virus infections. despite its proven efficacy, vidarabine suffers some limitations including: (i) metabolism by adenosine deaminase (ada) to its inactive hypoxanthine homolog (ara-h); (ii) low lipophilicity and membrane permeability and (iii) poor aqueous solubility, thus limiting options for parenteral and peroral delivery. our recent interest in vidarabine was triggered by our discovery that it was ∼5-fold more active against vaccinia (vv) and cow pox (cpv) viruses than was cidofovir in plaque reduction assays. its activity was enhanced about 10-fold by combination with 1 m 2 -deoxycoformycin (pentostatin, a potent inhibitor of ada) thereby providing significant superiority to cidofovir. from these results and our earlier studies on 5 -substituted vidarabine analogs (lipper et al., 1978. mol. pharmacol. 14, 366-369), we determined that minimizing metabolism of vidarabine by synthesizing 5 -amino acid substituted prodrugs gave a significantly more potent anti-pox virus agent. we found that amino acid ester prodrugs of vidarabine are active against vv at non-cytotoxic concentrations. further, using cell homogenates, purified enzyme and intact cell systems, we showed that the prodrugs are resistant to inactivation by ada. the prodrugs also had enhanced transport potential, most likely targeting the intestinal dipeptide transporter. finally, oral delivery of the prodrug to the small intestine resulted in a 10-fold increase in vidarabine plasma levels when compared to unsubstituted vidarabine. these properties make the prodrugs of vidarabine good candidates as orally bioavailable anti-pox virus agents that are stable in the presence of ada. acknowledgement: supported by funds from tsrl inc. and the university of michigan. ulf goerbig 1 , anne baum 1 , jan balzarini 2 , chris meier 1 1 university of hamburg, institute of organic chemistry, hamburg, germany; 2 rega institute for medical research, katolieke universiteit leuven, leuven, belgium the cyclosal pronucleotide system has been designed for an intracellular delivery of therapeutically active nucleoside monophosphates. as part of recent work on the cyclosal approach, the interaction of cyclosal nucleotides with cholinesterases has been investigated. it is known that organo-phosphates may act as irreversible inhibitors of cholinesterases (suicide mechanism). in the case of cyclosal nucleotides, cholinesterase inhibition could lead to unwanted side effects in a possible therapeutic application. there are two types of cholinesterase found in humans, the highly specific, physiologically important acetylcholinesterase (ache) and the much more unspecific butyrylcholinesterase (bche) of unknown physiological importance. fortunately, no inhibition of ache was observed for a variety of different cyclosal nucleotides. in contrast, bche inhibition was found in some cases. the anti-hiv-active 3,5-bis-tertbutyl-6-fluoro-cyclosal-d4t monophosphate is the first cyclosal derivative combining three desired properties: successful intracellular delivery of nucleotides, sufficient hydrolytic stability and strongly reduced inhibitor activity towards bche. because of the promising properties of this compound, we combined this mask developed for d4t with the antiviral active nucleoside analogues like d4a, dda, azt and acyclovir. in this contribution we present the synthesis, hydrolysis stability, inhibition behaviour towards bche and anti-hiv data of these new compounds. henning jessen 1 , wolfgang fendrich 1 , tilmann schulz 1 , jan balzarini 2 , chris meier 1 1 university of hamburg, institute of organic chemistry, hamburg, germany, 2 rega institute for medicinal research, katholieke universiteit leuven, leuven, belgium cyclosal-pronucleotides are used for the delivery of antivirally active nucleotides into cells via a ph triggered selective hydrolysis. to distinguish between intra-and extra-cellular environment enzyme-cleavable side chains were introduced in the aromatic moiety of the pronucleotide to enrich the compound inside cells. this behavior will further be described as "lock-in"effect. many other different cyclosal pronucleotides have been designed, all showing different hydrolysis properties and antiviral data, both originating from the nature of the cyclosal-moiety as well as of the nucleoside. to examine these differences, analytical tools of high accuracy and sensitivity were needed, being structurally as close as possible to the lead compounds. these requirements are met by intrinsically fluorescent nucleosides coupled to different cyclosal masking groups. for analysis of the purine-type nucleosides iso-da with high intrinsic fluorescence properties was chosen and converted into iso-a, iso-dda and iso-d4a. for the pyrimidine-type series the fluorescent nucleoside m 5 k was synthesized as well as the dideoxy-compound dm 5 k. these nucleosides were transformed into different cyclosalpronucleotides and tested for their suitability for fluorescence analysis. in fact, an improvement of sensitivity by a factor of 5000 compared to uv-detection was found for some of the compounds (pmol detection). for all compounds fluorescence and absorbance spectra were recorded to determine the absorption and emission maxima. the new compounds lacked activity against hiv-1 and hiv-2 strains. however, the compounds showed low cytotoxicity, which is important for their usability as fluorescent probes in cells. due to the analytical sensitivity, a simple model uptake study could be carried out, employing an u-tube with two aqueous phases, which were separated by an unpolar organic solvent simulating a diffusion barrier. the properties of the aqueous phases were varied and an enzyme-driven enrichment of a "lock-in"-modified intrinsically fluorescent cyclosal-pronucleotide passing the diffusion barrier could be simulated. nicolas gisch 1 , jan balzarini 2 , chris meier 1 1 university of hamburg, institute of organic chemistry, hamburg, germany; 2 rega institute for medical research, katholieke universiteit leuven, leuven, belgium cyclosal-pronucleotides efficiently deliver therapeutically active nucleoside monophosphates in human cells. "lock-in"-cyclosal-pronucleotides -the so-called second generation of cyclosal-compounds -have been designed to trap the compound by intracellular cleavage of esterase-cleavable moiety. one disadvantage of the "lock-in"-compounds is their high chemical stability, which leads to a delayed drug delivery. therefore, conceptually different, enzymatically activated cyclosalpronucleotides have been developed. in this concept lipophilic donor substituents attached to the aromatic ring are converted into a polar acceptor substituent by intracellular enzymatic cleavage. as a consequence the liberated acceptor group leads to a strong decrease in hydrolysis stability and a rapid formation of a charged intermediate is the result. from the phosphodiester intermediate the nucleotide is released subsequently. the concept, synthesis, characterization and in vitro antiviral evaluation of the third generation of cyclosal-pronucleotides will be presented. tomas cihlar 1 , richard mackman 1 , adrian ray 1 , dean boojamra 1 , lijun zhang 1 , deborah grant 1 , hon hui 1 , jennifer vela 1 , neil parkin 2 , yolanda lie 2 , kirsten white 1 , michael miller 1 , gerry rhodes 1 , manoj desai 1 1 gilead sciences, foster city, ca, usa; 2 monogram biosciences, so. san francisco, ca, usa background: n(t)rtis are currently used as a backbone of antiretroviral combination therapy. however, their long-term benefit can be limited by adverse effects, resistance development, drug-drug interactions, and sub-optimal efficacy in treatment-experienced patients. therefore, we searched for novel nucleotide analogs with improved pharmacological profiles. methods: phosphonomethoxy-2 -fluoro-2 ,3 -dideoxydidehydroadenosine (gs9148) was selected from a broad range of nucleoside phosphonate analogs. phosphoramidate prodrug technology previously explored with tenofovir was applied to gs9148, resulting in the identification of gs9131 (ethylalaninyl phenyl ester of gs9148). results: gs9131 exhibits potent anti-hiv-1 activity in primary lymphocytes and t-cell lines (ec 50 < 150 nm). low cytotoxicity (cc 50 > 100 m) was observed in multiple cell types including renal cells. diphosphate metabolite of gs9148 was shown to act as an obligatory dna chain terminator and a competitive inhibitor of hiv-1 reverse transcriptase (rt) (k i = 0.8 m). unlike ddi, d4t, or d4fc, neither gs9148 nor its prodrugs inhibited mitochondrial dna replication in hepg2 cells. in a phenosense assay, gs9148 retained its full activity against hiv-1 variants with k65r, m184v or l74v mutations in rt. viruses with ≥4 thymidine analog mutations showed ≤2fold reduced susceptibility to gs9148, a shift that was smaller than that of any other tested nrti. following an oral dose of 3 mg/kg gs9131 in dogs, the bioavailability of prodrug exceeded 20%, resulting in high intracellular levels (9.0 ± 2.3 m) and prolonged retention (t 1/2 > 24 h) of gs9148 diphosphate in blood lymphocytes. conclusions: both gs9148 and its prodrug gs9131 exhibit favorable in vitro pharmacological profiles including less resistance due to rt mutations than approved nrtis. gs9131 possesses good in vivo pharmacokinetic properties and thus represents an attractive development candidate with potential for clinical efficacy in both treatment-naive and nrti-experienced patients. martin mcdermott, gabriel birkus, ruth wang, holly macarthur, xiaohong liu, nilima kutty, tomas cihlar, craig gibbs, swami swaminathan, arnold fridland, william lee gilead sciences, inc., foster city, ca, usa gs-7340 and gs-9131 are alkylalaninyl phenyl ester prodrugs of tenofovir (tfv; 9-[(2-phosphonomethoxy)propyl]adenine) and a novel nucleotide analog fd4ap (phosphonomethoxy-2 -fluoro-2 ,3 -dideoxydidehydroadenosine), respectively. both gs-7340 and gs-9131 exhibit potent in vitro anti-hiv-1 activity, favorable resistance profile, and low cytotoxicity. compared to tenofovir disoproxil (viread), both prodrugs are significantly more stable in plasma and deliver >10-fold greater levels of active diphosphate metabolites into pbmcs in vitro and in vivo. the initial step in the intracellular activation of gs-7340 and gs-9131 is the hydrolysis of the alanine carboxyester by an unknown hydrolytic enzyme. the isolation and identification of this enzyme from human pbmcs is reported here. results: a major enzyme capable of cleaving gs-7340 and gs-9131 was purified from human pbmcs and was separable from esterases able to cleave alpha napthyl acetate (ana). the increase in specific activity of prodrug hydrolase achieved was 3500-fold. sds-page analysis showed the presence of a prominent protein band at 29 kda, which was identified by ingel tryptic digestion and ms/ms sequencing of the resultant peptides as lysosomal carboxypeptidase a (cathepsin a, ec 3.4.16.5, cata). the biochemical properties of purified prodrug hydrolase matched those of cata. recombinant cata and the isolated prodrug hydrolase displayed nearly identical susceptibility to hydrolase inhibitors and substrate preference against a panel of tenofovir phosphoramidate prodrugs. incubation of both enzymes with [ 14 c]gs-7340 and [ 3 h]difluorophosphonate resulted in the labeling of an identical 29 kda protein (catalytic subunit). both labeled bands reacted with polyclonal antibodies specific for human cathepsin a. finally, following incubation with gs-7340, approximately 6-9-fold lower intracellular concentrations of tfv metabolites were detected in fibroblasts from patients expressing non-functional cat a (cat a-cells) compared to normal control fibroblasts (cat a+ cells). center for drug delivery and nanomedicine, university of nebraska medical center, omaha, ne, usa nucleoside 5 -triphosphate (ntp) is the biologically active form of many antiviral nucleoside analogs capable of efficiently blocking the production of viral nucleic acids in infected cells. we describe novel microparticulate formulations for encapsulation of ntp, drug delivery and antiviral therapy of respiratory infections. polymer networks (poloxagels) consisted of crosslinked poloxamers and cationic polymer molecules were designed, synthesized and characterized by loading with ntp and interaction with cells. poloxagel-ntp formulations could be obtained by simple mixing of the aqueous solution of ntp with the aqueous dispersion of poloxagel and subsequent lyophilization. drug loading was equal up to 30% by weight. in this form, phosphates groups of ntp are complexed with amino groups of polycationic backbone of poloxagels, and the formulations could be stored at room temperature for many months without degradation of ntp. the particle size of aqueous poloxagel-ntp dispersions was low, with a hydrodynamic diameter of 0.1-0.2 m. the rate of passive drug release in physiological solution was from 33 to 50% of loaded drug during the 24-h period. these formulations were effectively consumed by many types of cells. significant amounts of drug and poloxagels were detected in the cellular interior after only 1-2 h of incubation. in the presence of cellular membranes drug release from poloxagel-ntp formulations was dramatically increased. we attribute this effect to the triggered release of the bound ntp as a result of competitive interaction of polycationic backbone of poloxagels with phospholipids of cellular membranes. mucoadhesive properties of poloxamers may additionally enhance binding of poloxagels with airways/lung epithelium. 5 -triphosphate of 1-␤-d-ribofuranosyl-1h-1,2,4-triazole 3-carboxamide (ribavirin) was synthesized using phosphorylation with a tris(imidazolyl) phosphate in a convenient one-pot approach. formulations of different poloxagels with the ribavirin 5 -triphosphate were prepared and characterized as prospective antiviral formulations for prophylactic and therapeutic treatments of respiratory infections including influenza a virus. aerosolic route of application of these antiviral formulations and associated problems are discussed. edwin gong 1 , ebrima gibbs 2 , joel oger 2 1 department of pharmacology and therapeutics, the university of british columbia, vancouver, bc, canada; 2 neuroimmunology lab, ubc hospital, department of medicine, the university of british columbia, vancouver, bc, canada ifn-alpha and ifn-beta are currently employed in the treatment of many viral diseases, especially chronic hepatitis. ifn-beta is also employed for the treatment of multiple sclerosis (ms), a chronic and often debilitating disease of the central nervous system. however, as with other protein therapeutics, long-term ifn therapy can lead to the development of binding and neutralizing antibodies to ifns and thus lead to deceased clinical effect of ifns. in order to measure the bioavailability of ifns and the level of neutralizing antibody, we have developed a realtime rt-pcr (taqman) assay by quantitating the expression of mxa (an ifn-induced protein) mrna. the nucleotide sequences of mxa deposited in the genebank were aligned, and a pair of primers and the hybridization probe were designed based on the conserved regions. a house keeping gene, gapdh, was used as a calibrator for relative quantitation. the rna standards were generated by in vitro transcription from cloned mxa gene in a plasmid vector. the reaction parameters were optimized. the assay was validated using pbmcs of ms patients that were treated with ifn-beta. for evaluation of the ifn bioavailability, the total rna was extracted from pbmcs and quantitatively detected by one-step rt-pcr for both mxa and gapdh. the results calculated by the 2 (− ct) method showed that the difference (signal-to-noise ratio) between samples with neutralizing antibodies and samples from untreated ms patients or healthy donors were approximately 60-70-folds. this indicates that our assay is a reliable method for determination of ifn bioavailability. v. lozitsky 1 , i. kravchenko 2 , v. larionov 2 1 research anti-plague institute, odessa, ukraine; 2 national university, odessa, ukraine transdermal delivery (td) of drugs is a novel method for treatment of diseases. td is carried out by the help of transdermal therapeutic systems (tts), which are multilayer plasters that contain active ingredients. td have a number of advantages, such as: (1) prolongation of the drug's action; (2) drug's concentration is maintained in therapeutic range; (3) there is no trauma to patient's skin while using td; (4) removing tts from the skin immediately stops drug's entering to the organism; (5) first-pass effect in the liver is reduced; and (6) many highly active drugs are irritating the gastro-intestinal tract if administered orally, others have a short half-life time-these drugs do not have downsides mentioned above if used as tts. in our previous research we elaborated tts containing rimantadine (ttscr) and studied its efficacy during experimental influenza in mice. we had established that transdermal delivery of rimantadine is more effective than oral administration. the aim of this work was to increase the efficacy of ttscr. to solve this task we studied the influence of some permeability enhancers on anti-influenza efficacy of ttscr during experimental infection. applied tts had adhesion hydrogel matrix (polyvinyl alcohol and 1.2-propylenglycol). they consisted of a base and a plastificator, which improves the administration of active substances through the skin and does not induce irritation. ttscr (1 mg/mouse) were applied on shaven backs of experimental animals. tts for other groups additionally contained one of such permeability enhancers as: 10 mg/mouse of dmso or 10 mg/mouse of octanol or 1 mg/mouse of papain. tts were applied on shaven backs of mice and stayed there from 1 day before infection to 10th day after challenge. mice of all groups were infected intranasally with influenza virus a/pr/8/34 (h1n1), which is highly pathogenic for them. challenge was carried out using four animals for each virus dilution within the range of 10 −1 to 10 −7 . deaths of animals were recorded for 14 days. the results showed that proteolytic enzyme papain increased the anti-influenza efficacy of ttscr on 1 log 10 tid 50 . dmso and octanol did not demonstrate such activity. mikhail dobrikov 1 , serguei vinogradov 2 , barbara ramsay shaw 1 1 department of chemistry, duke university, durham, nc, usa; 2 center of drug delivery and nanomedicine, and college of pharmacy, university of nebraska, omaha, ne, usa nucleoside reverse transcriptase inhibitors (nrti) are widely used in the antiviral chemotherapy. most nrtis require stepwise phosphorylation to the respective nucleoside triphosphates, which inhibit the viral dna synthesis. however, the emergence of hiv-1 reverse transcriptase-dependent drug resistance limits the effectiveness of treatment by nrtis. the ␣-p-borano-nucleotide analogues show several unique physico-chemical and biological properties: (i) enzymatic studies indicate that the rp-isomer of ␣-p-borano-2 ,3 -ddndps is a better substrate for cellular ndp kinase than the parent ddndp; (ii) neither isomer of the ␣-p-borano-ddndps is a substrate for mammalian pyruvate kinase and shows very poor inhibitory properties to this enzyme; (iii) the rp-(␣-p-borano)-ddntp isomers are better inhibitors of drug-and multidrug-resistant viral reverse transcriptases and are poor substrates for dnadependent dna polymerises; and (iv) after incorporation into viral dna the borano-ddnmp residues are more resistant to atp-dependent removal from viral dna than parent ddntps. to by-pass inefficient phosphorylation of the nrtis, several prodrugs of ␣-p-borano-nucleotide analogues have been previously synthesized. a more efficient delivery system for ␣-p-boranonucleotide analogues based on nanosized cationic polymeric gel (nanogel) is proposed. selective inhibition of drug-and multi-drug resistant viral rts, poorer inhibition of intracellular kinases and dna polymerases by the ␣-p-borano-nucleotide analogues, and their specific delivery into infected cells in the complex with nanogel particles suggest a new approach to the design of more powerful antiviral drugs. acknowledgement: this work was supported by the nih grant r01 al52061 to b.r.s. we have developed a high-throughput, cell-based assay to address the critical need for antiviral drugs for the treatment of influenza. in consideration of the demand to screen high volumes of compounds, we targeted the development of a 384 microtiter plate format for the assay. in this assay, the inhibition of the influenza-induced cytopathic effect (cpe) in mdck cells was assessed using the celltiter-glo luminescent cell viability assay by promega. this reagent measures the amount of atp present in cells, which is directly proportional to the number of metabolically active cells. validation studies were executed to establish optimal cell density, viral concentration, dmso tolerance for compound dilution, incubation time for virus-induced cpe and effective control drug concentration. additional parameters, such as assay variability, reagent and read stability, edge effects, and ic50 stability were also investigated during validation. we are currently initiating use of the assay to screen chemical libraries and will report our findings from library screens in addition to the aforementioned validation. we believe the approach will also provide a mechanism for discovery of new antiviral leads for influenza as well as avian flu. fundacio irsicaixa, hospital universitari germans trias i pujol, 08916 badalona, spain we have developed bacteriophage lambda based genetic screen that can be used to isolate and characterize site-specific proteases. this genetic screen system is based on the bacteriophage lambda ci-cro regulatory circuit, in which the encoded repressor ci is specifically cleaved to initiate the lysogenic-to-lytic switch. we have adapted this simple, safe and rapid genetic screening system to predict the activities and phenotypes of human immunodeficiency virus type 1 (hiv-1) proteases in the course of viral infection and antiretroviral therapy. a specific target for the hiv-1 protease, p17-p24, was inserted into the lambda phage ci repressor. the target specificity of the ci-hiv repressor was evaluated by coexpression of this repressor with an hiv-1 protease construct. upon infection of escherichia coli cells expressing the two constructs encoding the ci-hiv-1 repressor and hiv-1 protease, lambda phage replicated up to 1000-fold more efficiently than in cells that did not express the hiv-1 protease. this assay responds appropriately to well-known hiv-1 proteases inhibitors and can be used to search for new proteases inhibitors. the high level of specificity of this system, in which modest differences in catalytic efficiency can be quantified, should be also useful for the characterization of different mutant viral proteases. we further demonstrated the broad applicability of this protease assay using other viral proteases and their cognate cleavage sites, including hepatitis c virus (hcv) ns3 protease and severe acute respiratory syndrome (sars) coronavirus (cov) (scov) 3c-like protease. compared with other protease assay methods, this assay has the following advantages: safe, highly sensitive, highly specific, easy quantification, and rapid generation of different protease cleavage substrates using molecular cloning and expression. this system may be useful for the development of a screening method to identify viral protease inhibitors and should be also useful to characterize cellular, viral, or other infectious agent proteases with different activities and specificities. karen m. watson, todd b. parsley, robert w. buckheit jr. imquest biosciences, inc., frederick, md, usa a virus transmission and rapid resistance selection assay has been developed in order to quickly evaluate the biological properties of anti-infective test compounds and rationally prioritize them for further development. the transmission assay specifically evaluates the ability of test agents to suppress and clear virus replication from cultures during the serial passage of virus in the presence of fixed concentrations of the test compounds alone or in combination. the growth and expansion of virus in the infected cultures has been shown to occur through the replication of originally infected cells in the absence of virus spread, through direct virus to cell infection, and through cell to cell transmission. in order to sterilize a culture a test compound must possess the ability to specifically and potently interfere with virus replication by each of these three methods and must be able to inhibit the replication of resistant viruses which pre-exist in the viral inoculum and which rapidly grow in the presence of the fixed concentrations of the test agent. twelve pyrimidinediones being evaluated for potential use as both anti-hiv therapeutic agents and topical microbicides were evaluated for their ability to inhibit virus transmission and to define their ability to rapidly select for resistant virus strains. these compounds were evaluated in parallel with known anti-hiv agents that inhibit virus entry (t20) and reverse transcription (sustiva, uc781 and azt). the results of the transmission assays suggest that significant biological differences exist between antiviral compounds and even between highly related congeners of the same class of pyrimidinediones, suggesting that the transmission and rapid resistant selection assay measures important antiviral properties of anti-hiv agents. biological studies that evaluate the mechanisms of virus growth in the presence of high concentrations of test compounds will be described. laure deflubé 1 , kerstin angner 1 , anna overby 1 , david stein 2 , patrick iversen 2 , ramon flick 1 1 utmb, department of pathology, galveston, tx, usa; 2 avi biopharma, inc., corvallis, or, usa in the family bunyaviridae, several members on the genus phlebovirus have been reported to cause disease in humans or livestock. among these, rift valley fever (rvf) virus is an important human/animal pathogen. its widespread geographic distribution and its ability to produce severe human disease makes this virus a worldwide public health concern. the phosphorodiamidate morpholino-oligomers (pmo) are a class of dna-like antisense agents typically synthesized to a length of about 20 subunits and contain purine or pyrimidine bases attached to a backbone composed of six member morpholine rings joined by phosphorodiamidate intersubunit linkages. they have been shown to be effective antiviral compounds for different virus families, e.g. coronaviridae and flaviviridae. pmo bind to rna preventing translation of the viral rnas. we used our recently developed plasmid-based minigenome rescue systems for uukuniemi (phlebovirus model virus) and rvf viruses to screen antiviral compounds based on the morpholino antisense oligonucleotide approach. for this the antiviral compounds were appraised on the basis of reporter gene activity (fig. 1b) . the inhibitory effects of the same compounds were also tested by measuring reduction in virus titer (fig. 1a) , by monitoring changes in viral antigen production using an indirect immunofluorescence procedure and facs analysis, and analysis of genome transcription/replication by rt-pcr. indeed several pmos could be identified with interfering effect at a low ic50 on bunyaviral minigenome rescue as well as virus proliferation. based on these results, we plan to confirm antiviral activity of the most promising compounds in suitable animal models. we have shown that the fractal approach to the problem of viruscell interaction gives the unique possibility to process the data through the sequence of the direct and inverse fourier transforms. the studies were carried on the herpes simplex virus us-1 interacting with the hep-2 sensitive cell culture. the object was imaged as system of bright peaks formed as a result of laser diffraction on the structural elements of the virus-cell system. the whole virus-cell interaction information is inserted into computer in a fastest parallel way. the laser intensity peaks, which form the speckle image of the system under consideration, could be transformed into the hierarchical system of the circles (or squares) according to the choice of the researcher, but conserving the same d value, which depends only on the true intermolecular interaction potential. this potential, being characteristic for every stage of virus-cell interaction, is responsible for the given structure of the dynamic virus-cell system and the unique, but the typical form of the fractal cluster corresponding both to the system itself and its image as well, was processed by computer techniques. the hierarchical fractal design of the virus-cell system, proposed here for the first time, gives the universality, needed for the quantitative description of any possible combination of the virus and corresponding sensitive cell. it should be noted, as well, that the fractal microscope use for viruscell dynamic system imaging have all the properties, required from all other experimental tools of monitoring, including the reliability, reproducibility and preciseness. this device could be used in drug design biological test stages with the scope of time and efforts economy during the compounds libraries screening. the fractal microscope combined with the qsar drug design technique makes the antiherpetic drug design more competitive as compared to the regular approaches. acknowledgement: the authors are indebted to the partial support of the stcu grant #3147. we have investigated experimentally the fractal properties of diffraction images obtained by laser irradiation of virus-cell system. it was shown that the diffraction process is mathematically equivalent to the direct fourier transform of the said system's components modeled with simple geometrical figures (e.g. circles). each viral family could be coded and described quantitatively with the average size of the free viral particle and the type of its symmetry. we propose here to use the inverse fourier transform of the virus-cell system in order to get the real enlarged image of the viruses attacking the sensitive cell as well as the cell's structural transformation caused by the sequent stages of virus reproduction process. the set of bright and dark spots, which forms the virus-cell system's diffraction image, could be coded into set of numbers (matrix form of correlation vector-function) using the quantification procedure. the correlation function was used as presented in polar coordinates because the system has the axial symmetry (laser beam taken as main physical axis). the full information included into the image peaks' diameters and color index is transformed using inverse fourier technique into set of intersecting bright and dark circles. the full in vitro dynamics of the structural changes of the virus-cell system are described by the changes of circles' diameters and the area of their intersection. it was shown, also, that the magnification of the fractal microscope could achieve 10,000× to 100,000×, depending on the laser power used. proposed fractal microscope could be applied as well in vivo experiments until the required magnification will not make us to use projection laser with the output exceeding 25 mw. we have shown that the fractal microscope based on the inverse fourier transform could be applied successfully in pharmaceutical antiviral drug design, laboratory and clinical trials of new antiviral preparations, especially effectively in hierarchic qsar research. acknowledgement: authors are grateful to the support under the stcu grant #3147. we have previously reported bicyclic furano pyrimidines as potent and selective inhibitors of varicella zoster virus (vzv) , with subnanomolar activity for palkylphenyl substituted analogues . these compounds however are highly lipophilic and poorly soluble in water. we then reported a series of p-alkyloxyphenyl compounds containing a phenolic ether aiming to enhance water solubility whilst retaining antiviral activity (mcguigan et al., 2002) . we will now report the synthesis, characterisation and antiviral evaluation of a novel series of p-alkyloxyphenyls where there is at least one methylene spacer between the phenyl and ether group to potentially boost the pharmacokinetic profile. the alkyl chain length was fixed to retain a high clogp value, a parameter that has previously been shown to correlate with high antiviral potency . the target structures were prepared by the pd-catalysed coupling of a series of para-substituted alkoxyphenyl acetylenes with 5-iodo-2 -deoxyuridine, to give intermediate 5-alkynyl nucleosides, which were subsequently cyclised in the presence of cui to give the desired bicyclic systems. the antiviral activity, cytotoxicity, and solubility of these compounds are to be reported. we have previously reported on some novel nucleoside analogues containing and unusual furano bicyclic pyrimidine base and long side chain , which were discovered to be both potent exquisitely and selective towards the varicella zoster virus. following this discovery, three main sites for modification were identified and explored: (1) the side chain; (2) the bicyclic base; and (3) the sugar moiety. modification to the side chain by insertion of a phenyl ring, led to the most potent anti-vzv nucleoside to date (ec50 1 nm) . the investigation into modifications at the three sites stated above has continued and we herein report further adjustments to these analogues. replacement of the furo oxygen with sulfur on the parent nucleosides bearing an alkyl side chain has been reported to retain antiviral activity. however, those bearing a phenyl alkyl side chain are here shown to give a slight reduction in anti-vzv activity. modifications to the phenyl ring of the side chain have included halogen substitutions, and the fluorine in particular has produced some intriguing results in that, while the ortho and meta substitutions show some anti-vzv activity, the para analogue is completely devoid of antiviral activity. we now report further studies which include the di and tri substituted phenyl analogues. finally, we have also investigated sugar modification that has included substitutions of the 3 hydroxyl group. previous modifications which have replacements of the hydroxyl groups, resulted in loss of activity against vzv . we now present some new 3 substituted analogues which have provided interesting biological results. we have previously reported bicyclic furano pyrimidines as potent and selective inhibitors of varicella zoster virus (vzv) with subnanomolar activity for palkylphenyl substituted analogues srinivasan et al., 2001) . the sar is now further explored via the substitution of phenyl derivatives with electron withdrawing and electron donating groups. we now report the synthesis, characterisation, and biological evaluation of a novel series of mono substituted phenyl derivatives in order to probe the structure activity relationships in this region. the target compounds were synthesised under sonogashira conditions where a series of substituted phenyl acetylenes were coupled with 5-iodo-2 -deoxyuridine, to give intermediate 5alkynyl nucleosides that were subsequently cyclised in the presence of cui to give the desired bicyclic systems. diseases caused by herpes simplex virus (hsv) are widely distributed. prophylaxis and treatment of these infections are important health care tasks that require also the search, design and development of new antiherpetic drugs overcome drug resistance and toxic side effects of existing drugs. drug selection simply based on results of empirical screening is not very effective. computer-based technologies may help to optimize the structure of antiviral compounds as well as to design and develop new drugs. the objective of the present work is the quantitative structureactivity relationship (qsar) analysis of antiviral activity of various n,n -(bis-5-nitropyrimidyl)dispirotripiperazines in connection with consequent drug design. the well-established simplex representation of molecular structure (sirms) qsar approach has been used to fulfill this objective. it allows the molecular design of new effective antiviral drugs. thorough investigation of the relationship between: (a) cytotoxic (hela cells and gmk cells, cc 50 , g/ml); (b) antiherpetic activity (hsv-1 strain kupka, ic 50 , g/ml); and (c) selectivity index (ratio of cc 50 to ic 50 ) and the structure of 48 n,n -bis-5-nitropyrimidyl derivatives of dispirotripiperazine have been conducted. statistic characteristics for pls (partial least squares) models are quite satisfactory (r 2 = 0.816-0.991, q 2 = 0.637-0.868). the results are confirmed by experimental data. based on the obtained models, molecular fragments that promote and interfere with antiviral activity were defined. additionally, these models provide the possibility to predict molecular fragments that will enhance antiherpetic activity and to design new well tolerated highly virus-specific drugs. in summary, the developed simplex approach is an effective instrument for prediction and design of novel effective antiherpetic agents. several representatives of a series of 5-arylethynyl-2deoxyuridines (1a) bearing bulky aryl groups were recently shown to possess unexpected activity towards hsv-1. unlike common anti-hsv drugs, these compounds retain activity towards kinase-deficient acyclovir-resistant strains. therefore, an unusual mechanism of antiviral action is assumed. in order to investigate the mechanism and to discover more potent analogues we synthesized several novel 2 -deoxy (1a) and 2 -arabino (1b) uridine derivatives possessing different 5-arylethynyl substituents. dinucleosides 2 containing two uridine moieties coupled to a single polycyclic aromatic hydrocarbon (e.g. pyrene) represent another type of structural variation of nucleosides 1a. these compounds as well as some of 1a and 1b possess bright fluorescence that can be used in biological evaluations. cytomegalovirus (cmv) is a wide spread opportunistic pathogen which belongs to the beta subfamily of the herpesviridae. primary infection is generally asymptomatic resulting in life long latency. however, morbidity and mortality rates post-transplantation are greatly increased following reactivation or recrudescence of cmv. ganciclovir (gcv) and cidofovir (cdv) have both been successful in suppressing cmv viral replication in immunocompromised patients. although sustained use of these drugs has resulted in the emergence of multi-drug resistant strains of virus. in this study we used plaque reduction assays to determine the antiviral efficacy of two ribonucleotide reductase inhibitors, didox (dx; 3,4dihydroxybenzohydroxamic acid) and trimidox (tx; 3,4,5trihydroxybenzamidoxime) in inhibiting both wild type and drug-resistant strains of murine cmv (smith strain). the results presented here demonstrate that both dx and tx inhibit viral plaque formation in a dose dependent manner in both wild type and the resistant strain. a 43-and 39-fold increase in drug dose was required for cdv and gcv respectfully to inhibit plaque formation by 50% in the resistant strain (cdv wt: 0.03 m, r: 1.28 m/gcv wt: 3.17 m, r: 122.85 m). this compared to only a moderate increase in drug dose required for dx and tx to achieve 50% inhibition in the resistant strain (dx wt: 20.71 m, r: 28.88 m/tx wt: 7.12 m, r: 11.59 m), corresponding to a 1.4-and 1.6-fold increase respectfully. further work is currently underway to determine the possible mechanism of antiviral actions and toxicity profiles of these novel virostatics. in patients with human immunodeficiency virus (hiv) infection, coinfection with herpesviruses continues to be a problem for patients receiving antiviral hiv therapy. since treatment can be affected by the large number of drugs required for multiple infections, it would be useful to have antivirals that are active against both hiv and the herpesviruses. we reported previously that alkoxyalkyl ester prodrugs of cidofovir (cdv) are several logs more active against herpesvirus replication than unmodified cdv. to determine if this strategy would be effective for other acyclic nucleoside phosphonates which are active against hiv infections, hexadecyloxypropyl (hdp) esters were synthesized from 1-(phosphonomethoxyethyl)-cytosine (pme-c), 1-(phosphonomethoxyethyl)-5-bromo-cytosine (pme-5brc), 1-(phosphonomethoxyethyl)-5-fluoro-cytosine (pme-5fc), 9-(phosphonomethoxyethyl)-2,4-diaminopurine (pme-dap) and 9-(phosphonomethoxyethyl)-2-amino-4cyclopropylaminopurine (pme-cprdap) and assayed for activity against herpesvirus replication. overall, the hdp esters were more active than the unmodified acyclic nucleoside phosphonates, indicating that this is a useful strategy for increasing the antiviral activity of acyclic nucleoside phosphonates. one of the most active compounds was hdp-pme-cprdap which had ec 50 values of 0.2, 0.3, and 0.03 m in hff cells infected with hsv-1, hsv-2 or hcmv, representing a 12-26-fold increase in efficacy over the parent pme-cprdap. another promising compound was hdp-pme-dap, which had ec 50 values of 0.7, 0.2, and 0.6 um in hff cells infected with hsv-1, hsv-2, and hcmv, representing a 16-43-fold increase over the parent pme-dap. the results presented here indicate that modified acyclic nucleotides with antiviral activity against hiv also inhibit the replication of some of the herpesviruses. further evaluation of their activity against other herpesviruses that are a problem in hiv-infected patients, such as human herpesviruses type 6 and 8, is warranted and may provide new therapeutic options for patients with coinfections. julie m. breitenbach 1 , katherine z. borysko 1 , jiri zemlicka 2 , john c. drach 1 1 biologic & materials sciences, school of dentistry, university of michigan, ann arbor, mi, usa; 2 karmanos cancer institute, wayne state university school of medicine, detroit, mi, usa we previously described first (qiu et al., 1998. j. med. chem.) and second generation (zhou et al., 2004. j. med. chem.) methylenecyclopropane purines that have potent and selective activity against hcmv. strains selected separately for resistance to first-generation analogs (synadenol, synguanol) were 10-20-fold resistant to several first-generation purine analogs. similar resistance was observed to the second-generation guanine analog cyclopropavir [ic 50 's in plaque assays = 0.35 and 21 m, respectively for wild-type (wt) and synguanol-resistant (1982r) virus]. likewise a ul97 deletion mutant (prichard et al., 1996. j. virol.) was resistant to both first and second-generation compounds (ic 50 's = 2.1 and 0.25 m in wt; 100 and 15 m in ul97 del , respectively for synguanol and cyclopropavir). ul97 from the hcmv strain selected for resistance to the synadenol was sequenced and two mutations were identified: m460i and c603y. because hcmv with either m460i or the related c607y mutation alone was sensitive to synadenol and synguanol (baldanti et al., 2002 . antiviral res.), we hypothesize that two mutations are required for resistance to first-and second-generation analogs. this hypothesis was tested by construction of three strains of hcmv from hcmv ad169 bac with one, the other, or both mutations in ul97. as expected, the two strains with the single mutations were 3-to 6-fold resistant to ganciclovir but had little resistance to the first generation compounds synadenol and synguanol (0.5-to 1-fold). both strains were somewhat more resistant to the second-generation compound cyclopropavir (6to 8-fold) but less so than observed in the 1982r virus with two mutations. study of the resistance of the constructed virus with two mutations is underway. we conclude that a functional ul97 is required for activity against hcmv and that is likely that two mutations in ul97 are required for significant resistance. acknowledgement: supported by grants p01-ai46390 and r44-ai054135 from nih and funds from the university of michigan. svitlana zagorodnya 1 , nadiya nesterova 1 , inna alexeeva 2 , larisa palchikovskaya 2 , galina baranova 1 , alexander kobko 2 , anna golovan 1 1 zabolotny institute of microbiology and virology of nas of ukraine, kiev, ukraine; 2 institute of molecular biology and genetics of nas of ukraine, kiev, ukraine search of new effective preparations capable to inhibit herpesviruses reproduction is stipulated by their certain resistance to different groups of chemical preparations. new triazine bearing tricyclic bases and their n-glycosidic derivatives structures are widely used as potential antiviral agents. the objective of the present investigation was to study the activity triazine bearing tricyclic bases nos. 1 and 2, as well as n-glycosidic derivatives no. 3 against epstein-barr virus-lymphotropic and oncogenic virus from herpesviridae family. as a model of ebv-infection in vitro we used the line of lymphoblastoid b-cells raji, which infected by ebv. an inhibition of reproduction of ebv in a cell culture by no 1, no 2, and no 3 was determined by reduction of a number of genome-equivalents of ebv dna on a cell, which were revealed by quantitative pcr with use of primers and reagents "amply-senc-100 r" (russia). the first stage of investigation of substances was the analysis of their cytotoxicity for cell line raji. they have been studied in concentrations of 1000, 500, 250, 125, 64, 32, 16, 4 , 1, 0.5 and 0.1 g/ml. the concentrations that inhibited the quantity of live cells on 50% (id50) were equal to substances no. 1-750 g/ml, no. 2-625 g/ml and no. 3-125. the minimal inhibiting concentration (mic) of nos. 1, 2, and 3 was equal to 1 g/ml, because the amount of genome-equivalents of dna ebv on a cell was reduced with 28.0 up to 14. hence, the index of selectivity (is) was equal to 750 and 625 for triazine bearing tricyclic bases nos. 1 and 2, for n-glycosidic derivatives-125. in addition these compounds were also tested in transcription and replication model systems in vitro. our results indicate that bases and their n-glycoside derivatives effect rna and dna synthesis in different manner. r. sgarbanti 1 , l. nencioni 1 , g. macrì 2 , c. nucci 2 , u. benatti 3 , m. magnani 4 , e. garaci 5 , a.t. palamara 1 1 department public health sciences, university rome "la sapienza," rome, italy; 2 department biopathology, physiopathological optics, university rome "tor vergata," rome, italy; 3 department exp. medicine biochemistry section, university genova, genoa, italy; 4 inst. biochemistry, university urbino, urbino, italy; 5 department exp. med. biochem. sciences, university rome "tor vergata," rome, italy several studies have demonstrated that different viruses induce an imbalance in the intracellular redox state through a depletion of glutathione (gsh), the main intracellular antioxidant. the imbalance in the intracellular redox state represents a key event in the development of viral infection. indeed, our previous data showed that treatment with gsh prevents a decrease in intracellular gsh and inhibits replication of different rna and dna viruses in vitro and in vivo. our recent data demonstrated that a butanoyl derivative of gsh (gsh-c4), with increased hydrophobic properties, inhibited in vitro parainfluenza-1 and hsv-1 replication more efficiently than gsh. for this reason we evaluated the effectiveness of topical gsh-c4 administration in hsv-1-induced keratitis in rabbits. for infection, the corneal epithelium, previously scratched, was inoculated with 2 × 10 5 pfu/ml of hsv-1. gsh-c4, dissolved in a saline solution (150 mm, 100 ul/eye), was administered as eyedrops four times daily for ten days. a saline solution was used for the control group. the clinical evaluation of conjunctival and corneal involvement, performed by using 0.5% fluorescein sodium eyedrops and a slit lamp fitted with a cobalt blue filter, demonstrated that gsh-c4 treatment was effective in reducing the severity and progression of keratitis and conjunctivitis. moreover, in gsh-c4 treated animals, conjunctival hsv-1 titre, assayed by tcid50 on day 4 post-infection, was significantly reduced as compared to that of control animals (mean = 1.4 × 10 3 units/ml versus 1.1 × 10 5 units/ml, n = 10 for group). accordingly, similar results were obtained by measuring virus titre from the corneas of gsh-c4-treated animals versus placebo animals (mean = 3.5 × 10 3 units/ml versus 8.5 × 10 5 units/ml, n = 5 per group). such results highlight the antiviral activity of gsh-c4 in vivo and suggest that topical gsh-c4 treatment could be considered as complementary therapy of hsv-1-induced keratitis. debra quenelle 1 , deborah collins 1 , latisha pettway 1 , caroll hartline 1 , james beadle 2 , w. wan 2 , karl hostetler 2 , earl kern 1 1 university of alabama school of medicine, birmingham, al, usa; 2 department of medicine, university of california, san diego and veterans medical research foundation, san diego, ca, usa cytomegalovirus (cmv) can cause a wide variety of clinical manifestations in immunocompromised hosts or transplant recipients. we have utilized severe combined immunodeficient (scid) mice implanted with human fetal tissue and subsequently infected with hcmv or balb/c mice infected with mcmv to evaluate new antiviral therapies against cmv infection. in the current studies we used these two models to determine the efficacy of (s)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine ((s)-hpmpa), hexadecyloxypropyl-(s)-hpmpa (hdp-(s)-hpmpa), or octadecyloxyethyl-(s)-hpmpa (ode-(s)-hpmpa). in the hcmv model, human fetal thymus and liver (thy/liv) tissues were implanted under the kidney capsule of mice and inoculated 16-20 weeks later with 4700 pfu of hcmv. tissue samples were obtained at various time points for quantitation of hcmv titers by plaque assay. in general, replication of the toledo strain of hcmv in the implant tissue increased through 21-28 days and then gradually decreased to undetectable levels by 8 weeks post-infection. to determine efficacy of these compounds, oral treatment with vehicle or 10 mg/kg of (s)-hpmpa, hdp-(s)-hpmpa or ode-(s)-hpmpa was initiated 24 h after infection and continued for 28 days. cidofovir (cdv) at 20 mg/kg was administered i.p. daily as a positive control. results indicated that (s)-hpmpa, hdp-(s)-hpmpa and ode-(s)-hpmpa were highly effective in significantly reducing replication when compared to the vehicle control. in mcmv infected mice, hdp-(s)-hpmpa was highly effective in preventing mortality when administered orally at 30 or 10 mg/kg beginning 24 h post-viral inoculation and 30 mg/kg when treatment was delayed until 48 h postviral inoculation. these data indicate that these compounds were highly efficacious in two animal models of cmv infection and should be evaluated for use in hcmv infections in humans. cytomegalovirus (cmv) is a ubiquitous ␤-herpesvirus that asymptomatically infects immunocompetent individuals but leads to serious illness in immunocompromised individuals, such as transplant recipients, neonates and aids patients. thus, the need for well-tolerated and potent antiviral compounds with activity against cmv is well recognized. in our current studies, we have evaluated the in vivo activity of rep 9, a fully degenerate 40 mer phosphorothioated oligonucleotide against murine cytomegalovirus infection (mcmv) in mice. rep 9 has potent in vitro activity against hsv-1, hsv-2, hcmv, vzv, ebv, and hsv-6 (vaillant et al., submitted for publication). in our initial studies, infected mice were treated with rep 9 and compared to saline-treated infected control mice. compound was administered intraperitoneally for 5 consecutive days at 10 mg/kg, starting at 2 days prior to infection. mice were infected with 5 × 10 5 pfu mcmv on day 0, at 3 h post-treatment. sera were collected at −22 h, at 36 hpi, and at 3 dpi for elisa analysis of ifn␥ production. spleens and livers were collected at 3 dpi for determination of virus titers. at 3 dpi, virus titers in the spleens and livers were significantly reduced by rep 9 treatment as compared to control mice. splenomegaly was observed in infected mice treated with rep 9 but not in saline treated, infected mice or in rep 9 treated, uninfected mice. ifn␥ levels in mice treated with rep 9 peaked at 36 hpi compared to 72 hpi for saline-treated control mice. these data suggests that immune stimulation might contribute to the antiviral activity of ps-ons, perhaps through ifn␥ levels. a second study comparing the in vivo activity of rep 9 with two oligonucleotide analogs that do not activate tlr-9 mediated immune stimulation suggests that direct antiviral activity of rep 9 and the analogs was the predominant therapeutic mechanism in vivo. moreover, one rep 9 analog exhibited even greater antiviral activity than rep 9 while causing no splenomegaly. additional experiments are underway to provide insights into the mechanism of action against mcmv infection. acknowledgement: supported by contract no1-ai-15438 from the virology branch, niaid, nih. kathy keith 1 , joseph maddry 2 , namita bansal 2 , kochurani jacob 2 , secrist john 2 , earl kern 1 1 department of pediatrics, university of alabama school of medicine, birmingham, al, usa; 2 southern research institute, birmingham, al, usa a series of novel antiviral agents was prepared based on lead compounds related to acyclic nucleoside phosphonates. these agents consist of a purine nucleus bearing a pendant phosphonic acid group. the design strategy was two-fold: (1) following the approach of the hostetler group, to mask or partially mask the anionic phosphonate as a lipophilic ester and/or as an amino acid phosphonamidate prodrug that could enhance cellular uptake and be cleaved intracellularly; and (2) to investigate new substituents at the purine 2-and 6-positions. for proof of concept, a phosphonomethoxyethyl adenine (pmea) scaffold was employed. over 100 analogs of pmea substituted at the purine 2-or at the adenine n-6 site have been synthesized and evaluated for activity against orthopoxvirus infections. many n-6 substituents other than the previously recognized n-cyclopropyl have shown antiviral activity, and these structure-activity relationships are being investigated. an exciting finding has been that introduction of several novel moieties at the purine 2-position particularly the hydrazino, hydroxylamino, or the cyclopropylamino groups resulted in several compounds with excellent in vitro activity. for example, octadecyloxyethyl (ode) 2-amino-n(6)-cyclopropyl pmea had ec 50 values of 0.03-0.07 m and ode 2-hydroxylamino-n(6)-cyclopropyl pmea had ec 50 values of 0.3-1.6 m against cowpox and vaccinia viruses, respectively, using a plaque reduction assay in hff cells. under these conditions the parent molecule, pmea, was completely inactive. these two compounds had cc 50 values of 30-70 m giving selective indices of 200-1000. these studies indicate that several modifications in the pmea scaffold can result in good antiviral activity against orthopoxvirus infections in vitro and the most active compounds are currently being scaled up for evaluation in animal models. isatin (2,3-dioxoindole), a versatile lead molecule for designing of potential bioactive agents, and its derivatives have been reported to possess inhibitory activity against a variety of pathogenic viruses. methisazone(n-methylisatin-3thiosemicarbazone) was one of the first synthetic antiviral agents used clinically for the treatment of orthopox virus infections. the presence of the thiosemicarbazone, however, can result in immunosuppresion and we have attempted to replace the thiosemicarbazone with a sulphonamide in order to modify the antiviral activity. the present work was performed to evaluate the antiviral activity and cytotoxicity of some novel 4-[(1,2dihydro-2-oxo-3h-indol-3-ylidene)amino]-n-(4,6-dimethyl-2pyrimidiny)-benzene sulphonamides against pox viruses such as vaccinia and cowpox virus in human fibroblast cells and the activity was compared with cidofovir(cdv). among the compounds tested,4-[(5-methyl-1,2-dihydro-2-oxo-3h-indol-3-ylidene)amino]-n-(4,6-dimethyl-2-pyrimidiny)-benzene sulphonamide(spiii-5me), was the most active compound with an ec50 value of 18 mol, compared with cdv, which had an ec50 of 20 mol against vaccinia virus. all the compounds were non-toxic (>300 lm)using a neutral red uptake assay. substitution of a halogen atom in 5th position of isatin was found to abolish the antiviral activity. this compound should be evaluated in orthopox infections in animal to determine its potential for development as an effective agents for treatment of these infections. acknowledgement: supported in part by contract no1-ai-30049 from virology branch, niaid, nih, usa. evgeny belanov 1 , svetlana kotovskaya 2 , nikolay bormotov 1 , sergey balakhnin 1 , olga serova 1 , nataliya perova 2 , zina baskakova 2 , galina dzhumbaeva 2 , valerii charushin 3 , oleg chupakhin 2 1 state research center of virology and biotechnology "vector", koltsovo, novosibirsk reg., russia; 2 ural state technical university, yekaterinburg, russia; 3 institute of organic syntheses, yekaterinburg, russia during this study, we synthesized a series of 1,2,4-benzotriazine ( fig. 1) derivatives in order to evaluate the structural features required for anti-orthopoxviruses activity. these derivatives were tested for cytotoxicity and activity against the vaccinia, cowpox, mousepox, monkeypox, and in some experiments with variola viruses in vero and mk-2 cells. the results from studies of structure-activity relationship revealed that only compounds containing phenyl group at c-3 and the alkoxy and fluoro substitutes in the benzene ring of benzotriazines showed anti-orthopoxviruses activity. the antiviral activity was reduced or lost after substitution with other substitutes. thus, we find a new class of heterocyclic compounds with antiviral activity. acknowledgment: this research was funded by istc project #1989. yali chen, guang yang, kady honeychurch, dennis hruby, robert jordan siga technologies, inc., 4575 sw research way-suite 230, corvallis, or 97333, usa we have recently discovered a highly specific and potent antiorthopoxvirus compound (st-246) via high throughput screening (yang et al., 2005. j. virol. 79, 13139-13149) . marker rescue of st-246 resistant variants localized compound resistance to the f13l gene that encodes a major orthopoxvirus envelope protein (p37), which is required for extracellular viral particle formation. p37 participates in wrapping of intracellular mature virus (imv) in membranes derived from the trans golgi or late endosomal compartment to produce intracellular enveloped virus (iev) that are transported to the cell surface to form extracellular virus particles. to gain insight into the mechanism of action of st-246, we examined the effects of st-246 on the production of the extracellular viral particles in bsc40 cells infected with recombinant vaccinia virus containing a gfp-tagged p37 protein. in the presence of st-246, iev particle formation was dramatically reduced, plaque formation was almost completely inhibited, and imv particles appeared to be retained in intracellular vesicles as revealed by electron microscopy. furthermore, st-246 prevented the intracellular localization of p37 to the late endosome compartment as measured by confocal microscopy. in contrast, st-246 did not affect localization of p37 expressed from a st-246 resistant virus variant. more intriguingly, the compound did not affect the intracellular localization of p37 in transfected cells. these results suggest that st-246 inhibits an unknown virusspecific activity that requires f13l. this work underscores the exquisite specificity of st-246 and supports continued development of st-246 as a potential anti-orthopoxvirus drug. guang yang, chris harver, dennis hruby, robert jordan siga technologies, inc. 4575 sw research way, suite 230 corvallis, or 97333, usa st-246 is a potent, orally bioavailable anti-orthopoxvirus compound that is active in vitro and in vivo. the frequency of naturally occurring st-246 resistant variants was measured by fluctuation analysis and found to be 3.58 × 10 −6 . marker rescue of drug resistant variants localized changes associated with reduced compound susceptibility to the vaccinia virus f13l gene. the spectrum of mutations that confer st-246 resistance was determined using an error-prone pcr procedure to increase the frequency of compound resistance by 100-fold relative to the frequency of naturally occurring resistance. using this procedure, random point mutations were introduced into the f13l coding sequence by error-prone pcr and the mutated f13l alleles were transferred into wild-type virus genome by marker rescue. sequence analysis of the input error-prone pcr products prior to marker rescue identified numerous nucleotide changes in the f13l coding sequence, some of which created nonsense mutations. virus recombinants were selected that formed plaques in the presence of drug selection. this powerful selection procedure enriched for viruses that produced functional, st-246 resistant, f13l proteins. sequence analysis of the compound resistant f13l alleles identified numerous silent mutations scattered throughout the f13l coding sequence and 27 point mutations leading to amino acid changes that clustered around amino acid positions 258-302 within the f13l gene. seven of these mutations resulted in single amino acid changes and could be correlated with reduced compound susceptibility. taken together, these results suggest that: (1) mutations in at least 7 positions within f13l can confer resistance to st-246 and (2) st-246 resistant mutations cluster to a 58 amino acid domain in a region of the protein of unknown function. several 5-substituted pyrimidine analogs were identified as having antiviral activity against cowpox virus (cv) and vaccinia virus (vv) in primary human foreskin fibroblast cells. molecules containing benzopyran, cyanovinyl, and pyrazolone moieties at this position exhibited significant antiviral activity against both these viruses. three compounds in this series had ec 50 values below 10 m in a plaque reduction assay against both cv and vv. the antiviral activity of these compounds was also determined against herpes simplex virus (hsv) in a plaque assay. two compounds with cyanovinyl derivatives at the 5 position had ec 50 values below 15 m against both hsv-1 and hsv-2, whereas other substituents at this position exhibited weaker activity against one or both of these viruses. analogs containing the benzopyran substituents were the most effective against varicella zoster virus (vzv) and yielded ec 50 values below 10 m in a plaque reduction assay. none of the compounds were active against human cytomegalovirus. interestingly, all of the compounds were much less effective in a thymidine kinase (tk) negative strain of cv suggesting that the activation by this enzyme was important in their mechanism of action. tk deficient strains of hsv were also comparatively resistant to some of the compounds. the tk dependence of these compounds in cv and hsv taken together with the lack of activity against cytomegalovirus replication suggests that activation by a viral tk is important in their mechanism of action. these results indicate that pyrimidine analogs with large substituents at the 5 position are substrates for the distinct tk homologs encoded by the herpesviruses and orthopoxviruses and suggest that they may be effective against infections with these viruses. synthesis and testing of additional analogs is warranted and should help identify the most potent analogs for in vivo testing. department of pediatrics, university of alabama school of medicine, birmingham, al 35233, usa n-methanocarbathymidine ((n)-mct) is a conformationally locked nucleoside analog that is active against some herpesviruses and orthopoxviruses in vitro. this compound inhibits the replication of herpes simplex virus (hsv) with ec 50 values below 1 g/ml, and vaccinia virus (vv) and cowpox virus (cv) with ec 50 values of 0.55 and 1.5 g/ml, respectively. assays using a thymidine kinase (tk) negative strain of cv yielded ec 50 values 14-fold greater than a tk positive isolate. similarly, a tk negative strain of hsv-1 was 90-fold less sensitive to the drug than wild-type strains. thus, the antiviral activity of this molecule is dependent on the type i tk in hsv and the type ii tk expressed by vv and cv viruses, suggesting that it is a substrate for these divergent forms of the enzyme. the drug is also a good inhibitor of viral dna synthesis in both viruses and is consistent with inhibition of the viral dna polymerase once it is activated by the viral tk homologs. it is also possible that the phosphorylated forms of the drug may inhibit other enzymes such as thymidylate synthetase and inhibit viral dna synthesis indirectly. the interesting tk dependence of this molecule explains the rather unusual spectrum of activity that includes orthopoxviruses, alphaherpesviruses, epstein-barr virus (ebv), and human herpesvirus 8 (hhv-8), since these viruses all express molecules with tk activity that could phosphorylate and thus activate the drug. conversely, n-mct is ineffective against the betaherpesviruses because they do not encode tk homologs. the compound is also highly effective in reducing the mortality of mice infected with cv, vv, and hsv when treatment is initiated 24 h after infection and at doses as low as 17 mg/kg. these results indicate that (n)-mct is active in vitro and in vivo and its mechanism of action suggests that the molecule may be an effective and selective therapeutic for orthopoxvirus and certain herpesvirus infections and that it warrants further development. we have previously reported the isolation and characterization of drug-resistant mutants obtained following repeated passages of the vaccinia virus (vv, lederle strain) in the presence of increasing concentrations of cidofovir (cdv). cdvr mutants encoded two mutations (a314t and a684v) not related to genetic polymorphism. we have now introduced these mutations in the pathogenic strain w western reserve and characterized the drug-susceptibility profile of the recombinant viruses and their pathogenicity in mice. both the a314t and the a684v recombinant viruses proved to be resistant to cdv and related compounds, such as cyclic cdv and -propoxy]pyrimidine}. the virus bearing both substitutions proved to be more resistant to cdv than the single mutants. interestingly, the a314t and the a684v mutants differed in their sensitivity to phosphonoacetic acid (paa); the a314t and the a684v mutants being, respectively, hypersensitive and resistant to paa. in contrast, the double mutant showed no change in sensitivity to paa as compared to the wild-type strain. unlike the a684v mutant that showed only a two to three-fold decrease in susceptibility towards the 3-hydroxy-2-phosphonomethoxypropyl (hpmp) purine derivatives, the a314t mutant showed cross-resistance to the hpmp purine derivatives. it should be noted that in the process of selection of cdv-resistant mutants in the presence of increasing concentrations of the compound, the a314t mutation appeared before the a684v substitution, and the latter mutation only occurred in conjunction with a314t. when tested for virulence in a lethal intranasal infection model in mice, all cdvr recombinant viruses proved to be attenuated, suggesting that cdvr mutations are associated with reduced pathogenicity. furthermore, we found that cdv at a dose of 50 mg/kg/day for 5 days was still able to protect mice (in terms of body weight loss) against an intranasal challenge with the a314t + a684v recombinant virus. evaluating the use of cpg dna as an antiviral therapy amanda phelps, linda eastaugh, amanda gates, david ulaeto, arthur krieg 1 defence science and technology laboratories (dstl), salisbury, wiltshire, uk; 6 coley pharmaceuticals ltd., ottawa, ont., canada at present there are no licensed antivirals against orthopoxvirus infections such as variola or vaccinia virus (vacv). although a stockpile of smallpox vaccine exists and has utility as a post-exposure treatment to infection, it is a live viral vaccine and as such cannot be administered to those with contraindications. bacterial dna contains unmethylated motifs that, together with their flanking regions, can stimulate an innate immune response. synthetic cpg dna mimics the immunostimulatory activity of bacterial dna and is recognised by intracellular toll-like receptor 9. there are four classes of cpg dna all of which have different properties, eliciting distinct initial immune responses. previous studies using an established lethal respiratory model of poxvirus infection demonstrated that a class b cpg dna (7909) could provide protection from lethality against vacv in balb/c mice when administered up to 7 days prior to challenge. in order to evaluate efficacy balb/c mice were challenged intra-nasally with vacv and treated with doses of 7909 ranging between 15 and 100 ug/mouse. treatment was administered intra-nasally under light anaesthesia either on the day of challenge, 1, 2, 3, or 4 days post-challenge. efficacy was determined by percentage body weight loss post-challenge. the optimum survival rate observed was 60% when treated with 30 ug 1 day post-challenge (70 mld50 challenge). a survival rate of 80% was observed when treated with 50 ug 2 days post-challenge (40mld50 challenge). the delay of treatment to either 3 or 4 days post-challenge was ineffective, indicating that the window of opportunity for delivery of 7909 is within 2 days. multiple doses of 7909 were used to attempt to extend this window of opportunity, delivering 7909 twice within a 3-day period. interestingly, this had a considerable detrimental effect, actually accelerating the onset of disease and ultimately death. further work is required to optimise the use of cpg dna as a potential antiviral therapy, and there is evidence to suggest that they may have immense utility as part of a co-administration therapy with other antiviral compounds, an area of work currently under investigation. © crown copyright dstl 2005. department of virology, hebrew university, hadassah medical school, jerusalem, israel the pathogenicity and immunogenicity of the lister (elstree) strain of vaccinia virus, used for vaccination against smallpox, was studied in the mouse model. the virus did not reach the brain when inoculated intranasally, but when injected intracranially at a dose of 5 × 10 5 plaque forming units (pfu), was lethal for 50% of the mice. lower doses of virus caused the mice to initially loose some weight but they completely recovered thereafter. a significant level of protection against a lethal dose of the wr strain was achieved in mice following immunization with the lister strain, while higher doses and repeated vaccination procedure, were required with modified vaccinia virus ankara (mva). we found that the lister vaccine strain applied in israel is comprised of heterogeneous virus population. we isolated and plaque-purified three virus variants differing in their plaque size in bs-c-1 cell cultures. they were named: l-large plaque, m-medium plaque and s-small plaque variants. these isolates could be neutralized by rabbit antibodies prepared against the western reserve strain of vaccinia virus and their one-step growth curves in bs-c-1 cells were quite similar. however, they differ in their pathogenicity to mice following intranasal inoculation of 10 7 pfu, or an intracranial injection of 5 × 10 4 pfu; the s variant being more virulent than the other two variants and resembles the pathogenicity of the lister strain. activity was also determined against a thymidine kinase (tk) deficient vaccinia virus in mouse and monkey cells. the potency of (n)-mct was similar to that seen with wild-type virus, suggesting that a cellular enzyme may be more important than viral tk to phosphorylate the compound. mice were intranasally infected with cowpox and vaccinia viruses followed 24 h later by intraperitoneal treatment with (n)-mct (2x/day for 7 days) or cidofovir (1x/day for 2 days). (n)-mct treatment at 100 and 30 mg/kg/day resulted in 90 and 20% survival from cowpox virus infection, respectively, compared to 0% survival (placebo). statistically significant reductions in lung virus titers on day 5 occurred in 10, 30, and 100 mg/kg/day treated mice. these doses did not spare mice from lethal vaccinia virus challenge, however, but the 30 and 100 mg/kg/day treatments significantly reduced day 5 virus titers and lung weights, and the 100 mg/kg/day treatment reduced lung consolidation. cidofovir (100 mg/kg/day) protected all animals from death in both models. the evaluation of (n)-mct may be limited to mice based upon its greatly reduced efficacy in the cells of higher animals. acknowledgement: supported in part by contract no-1-ai-15435 from the virology branch, niaid, nih. chelsea byrd 1 , elena sbrana 2 , shu-yuan xiao 2 , marina siirin 2 , robert tesh 2 , dennis hruby 1 , robert jordan 1 1 siga technologies, inc., corvallis, or, usa; 2 university of texas medical branch, galveston, tx, usa st-246 is a potent small molecule inhibitor of orthopoxvirus replication that has been shown to protect mice from lethal challenge with vaccinia and ectromelia viruses. here we report the results of preliminary trials that show efficacy of st-246 against severe monkeypox virus infection in the ground squirrel model. ground squirrels infected with less than 1 pfu of monkeypox virus develop a fulminant disease resembling human hemorrhagic smallpox: the most severe and lethal form of the disease. oral administration of st-246 at 100 mg/kg once per day for 14 days protected ground squirrels from a lethal challenge with 100 and 1000 pfu of monkeypox virus. compound treated animals showed no weight loss or evidence of disease, and blood chemistry values were similar to uninfected animals. in contrast, placebo-treated animals showed elevated liver enzyme (alt and ast) levels and all animals died by day 12 post-infection. when treatment with 48, 72, and 96 h, 100% protection was observed in the 24, 48, and 72 h groups, and 66% protection in the 96 h group. severe pathologic changes were observed in the organs of the animals receiving placebo, especially in the lungs, liver, and spleen. in contrast, the organs of the animals receiving st-246 at 0, 24, 48, and 72 h postinfection appeared grossly and microscopically normal. thus, st-246 appears to be a promising candidate for continued development as a therapeutic agent for severe orthopoxvirus infection. inge vliegen 1 , guang yang 2 , dennis hruby 2 , erik de clercq 1 , robert jordan 2 , johan neyts 1 1 rega institute for medical research, k.u. leuven, belgium; 2 siga technologies, inc. corvallis, or, usa st-246 is a potent inhibitor of the replication of various orthopoxviruses. resistance of cowpoxvirus to st-246 maps to a mutation in v061, which is homologous to vaccinia virus f13l (yang et al., 2005. j. virol.) . the latter encodes the envelope protein p37 required for production of extracellular virus. deleting f13l resulted in a virus ( f13l-vac) that is replicationcompetent in cell culture but that produces smaller plaques than the wild-type wr-vac. whereas intravenous (i.v.) inoculation of nmri mice with 2 × 10 5 pfu of wr-vac resulted in 59 ± 11 pox tail lesions per mouse, the same inoculum of f13l-vac caused no lesions (p < 0.001). athymic nude (nu/nu) or scid mice inoculated iv with 2 × 10 5 pfu f13l-vac did not develop tail lesions. the mean day of death in nu/nu mice inoculated with f13l-vac was 22 ± 1 days as compared to 9 ± 1 days for wr-vac-infected mice (p < 0.001); scid mice survived the infection. we next studied whether f13l-vac is able to protect mice against a subsequent infection with wr-vac. to mimic the human vaccination protocol, nmri mice were infected intracutaneously (i.c.) by means of scarification at the lumbosacral area with 5 × 10 5 pfu f13l-vac or placebo. none of the infected mice developed lesions at the inoculation site. one week later, animals were infected ic with 5 × 10 5 pfu of wr-vac. all placebo animals, but none of the f13l-vac animals developed poxvirus lesions. in a second set of experiments, mice were again inoculated ic with placebo or f13l-vac and were infected one week later with 2 × 10 4 pfu of wr-vac by the iv route. placebo animals developed an average of 14 ± 4 pox tail lesions; no lesions developed in the f13l-vac animals (p < 0.001). in a third set of experiments, nmri mice were inoculated iv with either 2 × 10 4 pfu of f13l-vac or placebo, and none of the mice developed lesions. one week later, animals were inoculated iv with 2 × 10 4 pfu wr-vac. the placebo group developed an average of 11 ± 8 lesions as compared to 1.2 ± 0.7 lesions in the f13l-vac mice (p < 0.05). f13l-vac may thus be considered as a severely attenuated virus that may have potential for use as a smallpox vaccine. ji yuan 1 , travis lim 1 , shuan coughlin 1 , dexin qiu 1 , zhen liu 1 , dave stein 2 , decheng yang 1 1 the james hogg icapture centre for cardiovascular and pulmonary research, university of british columbia, vancouver, bc, canada; 2 avi biopharma, inc., corvallis, or, usa background: coxsackievirus b3 (cvb3) is the most common cause of viral myocarditis, but existing drug therapy is of limited value. antisense oligonucleotides (asons) designed to pair with viral rna could inhibit viral replication. however, the effectiveness of traditional asons is limited due to poor cellular uptake and degradation by nucleases. phosphorodiamidate morpholino oligomers (pmos) contain backbone modifications, which make pmos more resistant to nucleases. in addition, an arginine rich peptide (p007) is conjugated to the 5 end of the oligomer to improve its delivery into cells. these features make p007-conjugated pmos (p-pmos) promising candidates for the inhibition of cvb3 infection. methods: total 8 p-pmos targeting distinct regions of viral genome and one scrambled sequence were designed and chemically synthesized. fitc labeled p-pmos were used to observe their distribution of by confocal microscopy. viral protein vp1, viral titre, and cell viability were measured by western-blot, plaque assay, and mts assay, respectively. results: p-pmos showed increased cellular uptake compared to non-conjugated pmos. among the 8 p-pmos, p-pmo-6, targeting the internal ribosomal entry site in the 5 utr, showed the most potent anti-cvb3 ability in a dose-dependent manner. both infected hela and cardiomyocytes hl-1 cells treated with p-pmo-6 showed drastically reduced vp1 production and 3.0 log decreases in viral titres as compared to the controls. cell viability assay revealed that 83 and 89% of treated hela and hl-1 cells were still alive as compared to 11 and 10% of control-treated cells and 47% antiviral activity still existed after 5 days treatment. in addition, cells treated post-infection showed similar inhibition of viral replication. furthermore, the specificity of the p-pmos was demonstrated by their inability to inhibit rsv infection in hela cells. we have showed that p-pmos can effectively inhibit viral replication in vitro, providing a new possibility for antiviral intervention. picornaviruses are responsible for various human viral diseases including common cold, encephalitis, meningitis, myocarditis, etc. up to now, there is no specific antiviral therapy to treat or prevent such viral disease. the usage of modern computer technologies may help to solve this problem more effectively. the objective of the present study was the quantitative structure-activity relationship (qsar) analysis of antiviral activity of a set of [(biphenyloxy)propyl]isoxazole derivatives that inhibit cvb3 replication in hela cells. based on results from qsar, the structure of new potential antiviral agents should be predicted by using consequent molecular design. the qsar approach applied is based on simplex representation of molecular structure (sirms). the relationship between: (a) antiviral activity against the pleconaril-sensitive clinical cvb3 isolate 97-927 (ic 50 , g/ml); (b) cytotoxicity in hela cells (cc 50 , g/ml); and (c) selectivity index (si = ratio of cc 50 to ic 50 ), and structure of 21 [(biphenyloxy)propyl]isoxazole derivatives has been studied systematically. quite adequate qsar models (r 2 = 0.831-0.931, q 2 = 0.674-0.896) have been obtained using pls (partial least squares) method for all parameters studied. the models are in close correlation with experimental data. structural fragments with positive or negative influence on cytotoxicity as well as antiviral activity have been determined on the base of these models. for example, qsar analysis of antiviral activity of [(biphenyloxy)propyl]isoxazole derivatives revealed that the presence of m-nitrophenyl or p-trifluorophenyl fragment has distinctly negative influence on antiviral action. compounds with strong antiviral activity have to contain an oxadiazole fragment. moreover, our data allow the virtual screening and molecular design of new well-tolerated compounds with strong anti-cvb3 activity. ivanka nikolova 1 , roumena petkova 2 , boris atanassov 3 , stoyan chakarov 2 , angel s. galabov 1 1 institute of microbiology, bulgarian academy of sciences, sofia, bulgaria; 2 scientific technological service, ltd., sofia, bulgaria; 3 institute of organic chemistry, bulgarian academy of sciences, sofia, bulgaria analysis of the rna sequence of the disoxaril-resistant mutants of the coxsackievirus b1 was carried out. the wild-type disoxaril-sensitive strain (connecticut 5) and two disoxarilresistant mutants (one of them produced in fl cells and the other one isolated from brains of newborn mice) infected with coxsackievirus b1 and treated with disoxaril and a disoxarildependent mutant strain obtained from the resistant strain by 9 passages in cell culture were included in the present study. a rt-pcr assay with primer sets selected from a region of the coxsackievirus b1 genome coding for the capsid protein vp1 was carried out. a parallel comparative analysis of the sequences of resulting fragments from the disoxaril mutants studied and the genbank sequence of origin of the vp1 gene of coxsackievirus b1 was performed with the blast alignment tool. distinct alterations in the vp1 locus of the disoxaril-resistant and the disoxaril-dependent mutants compared to the sequence of origin from the genbank (namely, a deletion of uug at ntt. 2749-2751 and an insertion of uuu at nt.2769) were observed. high-degree similarity (97%) between the resistant mutant produced in cell cultures and the dependent strain was observed, while the similarity to the wild strain was only 91%. the resistant mutant obtained in mice was found to be very similar to the strain, developed in cell cultures. a putative 3-d model of the spatial folding of the target protein in disoxaril mutants is proposed. ralitsa vassileva-pencheva, angel s. galabov in previous study of ours we presented a new approach to combined application of antivirals-consecutive administration of the partners. this schedule could be considered especially suitable for treatment of enteroviral infections, in which the development of resistance is very rapid due to the extremely high viral mutation rate. this approach aims to restrict the resistance development in experiments in vivo, using antivirals with proved high efficiency in experiments in cell cultures. the screening of various double, triple, and quadruple combinations that we carried out showed that two of the triple combinations, namely disoxaril (win compound)/oxoglaucin (a new antiviral drug, developed in our laboratory)/ptu-23 (a classic enteroviral inhibitor) and disoxaril/oxoglaucin/guanidinehydrochloride (a classic enteroviral inhibitor) manifest significant effect of protection in newborn mice with neurotropic coxsackievirus b1 infection. in the current study the role of the chronology of arrangement of the antivirals included in the combinations was investigated. in the experiments carried out with the triple combination disoxaril/oxoglaucin/guanidine-hydrochloride, it was found that the optimal treatment course should start with disoxaril. the treatment course is quite successful when disoxaril is followed by guanidine-hydrochloride. the effect of the triple combination starting with oxoglaucine, followed by guanidine-hydrochloride was moderate. the course starting with guanidine-hydrochloride proved to be ineffective. furthermore, we studied the virus sensitivity to the inhibitorspartners (ic50 values) and some other phenotypic characteristics of the brain isolates, e.g. the size of the plaques and the pathogenicity for mice. recently our contribution to the development of new antipicornavirus agents has led to the discovery of 5methylthio-3-aryl-isoxazole-4-carbonitrile derivatives whose in vitro anti-coxsackievirus b1 activity were dependent on the nature of the substituents on the para position of the phenyl ring. particularly, compounds 5-methylthio-3-[4-(3-phenyl-1-propoxy)phenyl]isoxazol-4-carbonitrile (on-7) and 5-methylthio-3-[4-(4-phenoxy-1-buthoxy)phenyl]isoxazol-4-carbonitrile (on-10) exhibited an interesting antiviral activity with high selectivity indexes. in the present study, we investigated on the mechanism of action of these compounds. studies on time of addition experiments suggested that these compounds exert a different interference with an early step of the viral replicative cycle. in fact, compound on-7 was effective when added within 1 h after the end of the adsorption period and no reduction was observed if it was added during the adsorption period. whereas a reduction of virus titer was observed for on-10 when was added during the adsorption period, while no reduction was observed if the compound was added after this period (time 0). the influence of the compounds on virus adsorption step, studied by the infective center assays, indicated that on-10 primarily interferes with coxsackie b1 cellular attachment. at a concentration 100 times the id 50 , inhibition of adsorption of coxsackievirus by on-10 was complete, while similar concentration of on-7 had no effect. our experiments on neutralization of viral infectivity and on thermal stabilization demonstrated that the compounds were able to directly inactivate coxsackievirus, and the infectious titer was restored to the original value after extraction of the compound with chloroform. however, the compounds did not protect the viral infectivity against heat inactivation at the different concentrations used. the blood-brain barrier (bbb) fulfills a vital protective function by limiting entry of potential pathogens, toxins, and inflammatory cells into the central nervous system (cns). disruption of the bbb is a common component of many cns diseases, including viral diseases such as that caused by west nile virus (wnv). transforming growth factor-␤1 (tgf-␤1) has previously been shown to improve the function of an in vitro model of the bbb. we evaluated the role of the bbb in wnv infection in mice by determining the ability of intraperitoneally (i.p.) administered sodium fluorescein to move from the circulating blood to the central nervous system. to demonstrate bbb permeability a mean and normal range of permeability values was determined in 30 non-infected c57/bl6 mice. in subsequent experiments, any animal expressing a permeability value greater than 2 sd above the mean was considered abnormally high. we determined that elevations in bbb permeability can be detected in mice 8 days after subcutaneous inoculation with wnv. wnv inoculated animals were treated with doses of 3000, 1000, or 300 ng/kg/day of tgf-␤1 or with drug vehicle once daily via the i.p. route on 7 and 8 days post-virus inoculation (dpi), and then assayed for bbb permeability on 8 dpi. sixty-two percent (8/13) of placebo-treated animals had abnormally high permeability values, while animals treated with 3000 and 1000 ng/kg/day of tgf-␤1 had 29% (2/7) and 57% (4/7) of animals with abnormally high permeability values, respectively. in contrast, none of the animals treated with 300 ng/kg of tgf-␤1 (0/8) expressed abnormally high permeability values, which was significantly lower (p < 0.01) than placebo-treated animals. these results suggest that tgf-␤1 may improve the function of the blood-brain barrier in wnv infected mice. acknowledgement: supported by grant 1-u54 ai06357-01 from the rocky mountain regional centers of excellence, nih. and contract no1-ai-15435 from the virology branch, niaid, nih. people infected with west nile virus (wnv) usually see their physicians after showing symptoms suggestive of neurological infection. wnv infects the central nervous system (cns) of rodents 3-5 days after s.c. viral challenge. yet, most published animal studies begin therapeutic treatments before or soon after viral challenge. the question addressed in this study is if neuroprotective agents can be efficacious when administered early before brain infection or later after the virus is demonstrated to be in the brain. the drugs evaluated in wnvinfected rodents were nmda and ampa receptor antagonists, modulators of nitric oxide synthase (nos) and nitric oxide production, and riluzole for reducing glutamate excitotoxicity. serial doses of diethyldithiocarbamate (ddtc) and n(g)monomethyl-l-arginine (l-nmma), an inducer or inhibitor of nos, respectively, administered i.p. daily for 10 days beginning 4 h before viral challenge slightly improved survival of mice, but the difference was not statistically significant. tolerated doses of two nmda-receptor antagonists, flupertine (7 mg/kg) and mk-801 (1 mg/kg), and one ampa-receptor antagonist, gyki 52466 (10 mg/kg), were administered twice daily (b.i.d.) on 4 though 9 days post-virus inoculation (dpi). gyki 52466 slightly improved mouse survival and weight gain, but the difference was not statistically significant. talampanel, an ampa-receptor antagonist and a derivative of gyki 52466, slightly improved hamster survival (p ≤ 0.05) when treatment began on 5 dpi, but repeated experiments using different doses and slightly different protocols gave mixed results. riluzole, the only drug shown to improved survival of amyotrophic lateral sclerosis (als), presumably by reducing glutamate excitotoxicity, was not effective against wnv disease when administered b.i.d. beginning 5 dpi. overall, neuroprotective agents did not consistently improve wnv disease, although slight improvements in animal survival might be relevant to improvement of neurological sequelae in wnv-patients. acknowledgement: supported by contract no1-ai-15435 from the virology branch, niaid, nih. hamster and mouse models for west nile virus (wnv) disease were used in this study to identify infected cells of the central nervous system (cns) early in the course of infection. this information may be relevant to therapeutic strategies since most wnv-infected people visit their physicians after showing symptoms suggestive of neurological infection. we subcutaneously infected adult mice and hamsters using 105.3 tissue culture infectious doses of wnv. tissues of infected and control animals from 3 to 11 days post-viral injection (dpi) were fixed by cardiac perfusion using 4% paraformaldehyde. we localized wnv, neuronal and astroglial markers in the paraffin embedded tissue sections by immunofluorescence. the images were captured using the confocal microscope (bio-rad, mrc 1020). we observed the presence of wnv antigen in cns tissues of mice and hamsters as early as 3 and 5 dpi, respectively. a strong wnv-specific immunofluorescence staining was observed in the cytoplasm of neurons from the spinal cord, cerebellum, cerebral cortex, and midbrain of these rodents. the wnv-specific staining co-localized with neuron-specific markers; however, astroglial markers were not co-localized with wnv antigen in brain sections. the lack of tropism by wnv for astrocytes was also confirmed in primary murine astrocyte cultures. interestingly, infected neurons in the midbrain of 7-day infected hamsters co-localized with calbindin, which is a calcium-binding protein and mostly expressed in the interneurons of the cns. therapies were evaluated in hamsters or mice at a time-point when wnv-stained neurons were identified in the cns. acknowledgement: supported by grant 1-u54 ai06357-01 from the rocky mountain regional centers of excellence, nih. laboratory of virology, department of biological chemistry, school of sciences, university of buenos aires, argentina dengue virus (denv) is an arthropod-borne flavivirus that has re-emerged in recent years as an increasingly important public health threat with nearly 50 million infections occurring each year. at present neither specific antiviral therapy nor vaccine exists for the treatment and prevention of denv infections. carrageenans are sulfated galactans that can be extracted from red seaweeds and comprise diverse structures with a wide range of biological properties useful in biomedicine. in a previous study we have demonstrated the antiviral activity of commercialand -carrageenans against denv type 2 and 3 in vero (monkey kidney cells) and hepg2 (human hepatoma cells), showing inhibitory concentration 50% (ic 50 ) values in the range 0.14-1.1 g/ml and selectivity indexes (cc 50 /ic 50 ) in the range 1000-10000. in the present work we studied the mode of action of these polysulfates against denv-2 in vero and hepg2 cells, first analyzing the influence of time of addition of compounds on anti-denv activity by an infectious centre assay. the highest inhibitory effect was observed when the compounds were added during adsorption or at 1 h p.i., being ineffective at later times. then, the effect of compounds on virus adsorption and internalization was studied separately by a virus yield inhibition assay. significant antiviral efficacy was attained if compounds were present either only during denv-2 adsorption or internalization. the possible effect of carrageenans on viral protein synthesis, the subsequent stage of the virus cycle occurring during the first hour of infection, was analyzed by pulse-labeling with ( 35 s)-methionine. no alterations in denv protein synthesis in carrageenan-treated cells were observed. when cells were transfected with purified denv-2 rna in the presence of -carrageenan no inhibition in fluorescent cell focus formation and virus production was detected. besides, no significant direct virucidal effect on denv-2 was shown by the compounds. these results indicate that both denv adsorption and internalization seem to be the main target for these compounds, lacking effect on the steps that occur once the viral genome is inside the cell during in vitro infection of human and monkey cells. multiple members of the flavivirus genus of the family flaviviridae cause lethal hemorrhagic fever or encephalitis. the public health significance of the hemorrhagic fever and encephalitis caused by such flaviviruses is enormous and global and there is a tremendous need for antivirals. imino sugar glucosidase inhibitors have been shown to have selective antiviral activity against viruses such as bovine viral diarrhea virus (bvdv) and west nile virus (wnv) that have common requirements for their glycoprotein processing during virus production. we are developing imino sugar deoxynojirycin (dnj) derivatives through chemical synthesis of compounds with various alkyl side chains and antiviral testing against bvdv and wnv as well as in wnv subgenomic replicon assays. briefly, using a single step growth (virus yield reduction) assay for bvdv and wnv, a series of dnj derivatives containing various conformational locking side chains were shown to have antiviral activity. pre-liminary structure-activity relationships (sar) were obtained for further modification of the alkyl side chain and improvement of these dnj derivatives. the activity and mechanisms of action of these compounds will be presented. several flaviviruses cause life-threatening diseases in man. currently, there is no therapy available for these infections. in recent years, several highly selective inhibitors of the replication of hepatitis c virus (hcv) were designed. most small molecule inhibitors of hcv that are in preclinical or clinical development are either protease or polymerase inhibitors. most of these compounds are highly selective for hcv and are unlikely to exhibit activity against flaviviruses. nucleoside polymerase inhibitors, however, may have the potential to inhibit the replication of flaviviruses as well. we evaluated in vitro whether the active component of the anti-hcv compound valopicitabine, i.e. 2 -c-methylcytidine inhibits the replication of flaviviruses in cell culture. the compound was found to exhibit specific antiviral activity against yellow fever virus 17d (ec 50 = 3.1 g/ml in cpe reduction assays and >98% reduction at 5 g/ml as assessed by qpcr) and dengue fever virus type 2 (ec 50 = 16.5 g/ml in cpe reduction assays). the compound also efficiently inhibited west nile virus replication (>98% at 5 g/ml as assessed by qpcr and >98% by plaque reduction neutralization test at 50 g/ml). in the absence of any drugs for the treatment of flavivirus infections, it may be envisaged that nucleoside polymerase inhibitors, when marketed for the treatment of hcv infections, could be used off-label for the treatment of lifethreatening flavivirus infections. even if such drug would not be able to completely inhibit flavivirus replication, a partial reduction of the viremia during the acute phase of the infection may be sufficient to prevent the development of a fulminate disease and thus protect against virus-induced mortality. yuri klimochkin 1 , andrew shiryaev 1 , igor moiseev 1 , v sabynin 2 , larisa rustamova 2 , alexandr petkevich 2 1 state technical university, samara, russia; 2 institute of epidemiology and microbiology, minsk, belaruss arenaviruses are one of the most dangerous tools of bioterrorism in the view of pathogenicity and epidemiological threat. for the purpose of searching new remedies for treatment are-naviruses infections the synthesis of new derivatives of cage compounds has been carried out. the prepared compounds are bridgehead derivatives of cage compounds bearing different functional groups such as hydroxy, acylamino, alkoxycarbonylamino, alkylthiocarbonylamino groups as well as iminoalkyl adamantane derivatives, some adamantylated heterocycles and compounds containing two adamantane moieties in a molecule. the antiviral activity of the cage compounds has been studied in respect to arenaviruses lassa (sierra-leone strain) and pichinde (an-3739 strain) on the vero cells culture. different level of antiviral activity was shown by 15 compounds. the most active compounds are monosubstituted adamantane derivatives having sufur and nitrogen-containing substituent in the bridgehead position. the data on the activity confirm the availability of searching inhibitors of arenaviruses reproduction in the cage compounds series. brian gowen 1 , donald smee 1 , min-hui wong 1 , anne pace 1 , kie-hoon jung 1 , kevin bailey 1 , lawrence blatt 2 , robert sidwell 1 1 institute for antiviral research, utah state university, logan, ut, usa; 2 intermune, brisbane, ca, usa several arenaviruses endemic to the south american (junin, machupo, and guanarito) and african (lassa) continents are known to cause frequently fatal hemorrhagic fever. with the exception of ribavirin, which has demonstrated efficacy in cases of lassa fever, there are no other effective therapeutics for the treatment of arenaviral hemorrhagic fever. the outcome of treatment is ultimately dependent upon early diagnosis and the tolerability of ribavirin by patients at the high doses required for effective antiviral activity. we have recently demonstrated that consensus interferon-alpha (ifn-alfacon 1) can protect hamsters from lethal pichinde virus (pcv) infection (gowen et al., 2005 . antimicrob. agents chemother.), which serves as a model for acute arenaviral disease in humans. here we demonstrate highly effective therapy through the combined use of ribavirin and ifn alfacon-1 for the treatment of pcv infection in hamsters. ribavirin was given orally, twice per day for 7 days, and ifn alfacon-1 was administered intraperitoneally, once per day for 10 days. treatments were initiated 1-5 days post-infection with various dose combinations, many which were less than optimal when the drugs were given independently. combining suboptimal doses of ribavirin (5-10 mg/kg/day) with ifn alfacon-1 (5-10 mg/kg/day), we were able to show increased protection from mortality, reduced viral burden and liver disease, and greatly extended survival times as compared to treatments where drugs were administered alone. our data indicate that synergistic activity resulted from combination therapy and that this activity may slow down the progression of disease and decrease fatality rates seen with severe arenaviral infections. further, combination therapy reduces the effective dosage of ribavirin, which would serve to limit its toxicity. acknowledgement: supported by contract no1-ai-15435 from the virology branch, national institute of allergy and infectious diseases, national institutes of health. slobodan paessler 1 , laure deflubé 1 , andrew vaillant 2 , jean-marc juteau 2 , ramon flick 1 1 department of pathology, university of texas medical branch, galveston, texas, usa; 2 replicor inc., laval, que., canada rift valley fever virus (rvfv; genus phlebovirus, family bunyaviridae) is an arbovirus transmitted by many species of mosquitoes. this virus is a major public health concern in sub-saharan africa and egypt, which spread to yemen and saudi arabia. in this area, rvfv is responsible for dramatic epidemics/epizootics underlining the need for efficient antiviral/prophylactic measures. rep 9 is a 40 mer phosphorothioate oligonucleotide, which has previously been shown to have broad-spectrum activity in several viruses (vaillant et al., submitted for publication) . we used a vaccine strain (mp12) as well as the wild-type rvfv (zh501), to test the ability of rep 9 to inhibit bunyavirus proliferation. in vitro data showed reduction of virus titer for both strains using rep 9 at nanomolar concentrations. moreover, the absence of the phosphorothioate modification in a stabilized rep 9 analog resulted in a loss of antiviral activity, suggesting that as in other viruses, the increased hydrophobicity of rep 9 is essential for its antiviral activity. based on the inhibitory activity observed in vitro, we started with in vivo efficacy studies by utilizing a validated mouse model used in our laboratory. more animal experiments are ongoing to confirm the in vitro results and to evaluate the antiviral effect of the rep 9. adriana garozzo 1 , rossella timpanaro 1 , aldo stivala 1 , gianna tempera 1 , christian c.c. cutrì 2 , angelo castro 1 1 department of microbiological sciences, university of catania, via androne 8, 95124 catania, italy; 2 department of pharmaceutical sciences, university of catania, viale a. doria 6, 95125 catania, italy our previous studies described the synthesis and the antiviral activity of 3,4,5-trisubstituted isothiazole derivatives that were found to be particularly effective against picornaviruses. compound 3-methylthio-5-phenyl-4-isothiazolecarbonitrile (is-2) exhibited an interesting anti-poliovirus activity with high selectivity index. in the present study, we investigated on the mechanism of action of this compound. studies on the time of is-2 addition to poliovirus type 1 infected cells suggested that the compound may inhibit some early processes of viral replication. in order to determine its mechanism of action, we evaluated the rate of attachment and internalization of purified [ 3 h]uridine-labeled poliovirus to hep-2 cells in the presence or absence of is-2. no effect on poliovirus adsorption and internalization to host cells was detected. we also investigated the influence of the compound on virus uncoating using labeled poliovirus and measuring the radioactivity of oligoribonucleotides formed from viral rna susceptible to ribonuclease. these experiments demonstrated that poliovirus uncoating is influenced by is-2 action. justin julander 1 , aaron olsen 1 , john morrey 1 , lawrence blatt 2 , kristiina shafer 1 , robert sidwell 1 1 institute for antiviral research, utah state university, logan, ut, usa; 2 intermune, brisbane, ca, usa alpha togaviruses are medically important arboviruses, with clinical cases occurring each year in north, south, and central america. the recent increase in the threat of the use of these viruses as bio-terrorism agents has led to increased efforts to develop therapeutic agents for treatment of these viruses. venezuelan (vee) and western equine encephalitis (wee) viruses have been listed as category b priority pathogens by the national institute of allergy and infectious disease (niaid). the goal of these studies was to characterize animal models for vee and wee for use in evaluation of antiviral therapies. c3h/hen mice were infected through the intranasal (i.n.) route with a vaccine strain of vee, tc-83. virus was detected in the brain 2 days post-viral injection (dpi). brain titers increased to a peak titer of 10 9.5 50% cell culture infectious doses per gram tissue (ccid 50 /g) on 4 dpi, maintained a titer of 10 9 ccid 50 /g through 7 dpi, and dropped slightly to 10 8.6 ccid 50 /g by 8 dpi. virus was also detected in spleen, liver, and kidney. treatment of vee-infected mice with interferon alpha b/d, a human consensus interferon, resulted in 100% survival, whereas all placebotreated animals died by 9 dpi. syrian golden hamsters were infected with 10 3 ccid 50 wee through intraperitoneal (i.p.) injection. morbidity, including hind limb paralysis, tremors, nasal bleeding, and hunching, and some mortality were seen as soon as 4 dpi. the majority of deaths occurred on 5 dpi. virus was detected in all organs assayed (brain, liver, and spleen) with peak titers occurring 4 dpi. interferon alfacon 1 (ifn alfacon), a human consensus interferon, active in hamsters, was effective in significantly reducing mortality (p < 0.001 as compared to placebo). there was a trend for reduction of brain titers in ifn alfacon-treated animals (mean titer 10 4.8 ccid 50 /g) as compared with placebo (mean titer 10 9.5 ccid 50 /g), although this difference was not statistically significant. these models will be useful in screening potential antiviral agents for efficacy against vee and wee. acknowledgement: supported by contract no1-ai-15435 from the virology branch, niaid, nih. justin julander 1 , kristiina shafer 1 , john morrey 1 , lawrence blatt 2 , robert sidwell 1 1 institute for antiviral research, utah state university, logan, ut, usa; 2 intermune, brisbane, ca, usa yellow fever virus (yfv) has caused significant morbidity and mortality for centuries. primates were the only animal models for visceral yfv. recently, hamsters were found to have morbidity and mortality when injected with a hamster-adapted jimenez strain of yfv (tesh et al., j. infect. dis. 183, 1431 -1436 . the objective of this study was to characterize this model of yfv viscerotropic disease for the study of effects of antiviral compounds and to test compounds with known efficacy for use as a positive control. animals were challenged with a 10 −4 dilution (a dilution previously shown to cause high mortality) of a liver homogenate made from livers taken 3 days post-viral injection (dpi) from hamsters challenged with the jimenez strain. there was 66% mortality in animals challenged with the virus up to 9 dpi. virus titers in the liver peaked 6 dpi as determined by qrt-pcr. a significant increase in serum levels of alt (6 dpi), alkaline phosphotase (6 dpi) and bilirubin (6 dpi), and a significant decrease in amylase (8 dpi), albumin (6 dpi), and glucose (6 dpi) were observed. hepatic icterus was observed in hamsters that exhibited disease signs at the time of necropsy. hamsters were treated with ribavirin or interferon (ifn) alfacon 1, a consensus interferon. ribavirin and ifn alfacon 1 both significantly (p < 0.001) reduced mortality as compared with placebo-treatment. there was also significant reduction in weight loss with ribavirin (p < 0.05) and ifn alfacon 1 (p < 0.01) treatment as compared with placebo. disease signs, such as lethargy and lying prostrate, were also reduced with treatment of ribavirin and ifn alfacon 1. viral liver titers from treated animals were not significantly different from titers in placebotreated animals. the hamster model of yfv disease will serve as a suitable model for the evaluation of antiviral compounds for efficacy against the virus. acknowledgement: supported by contract no1-ai-15435 from the virology branch, niaid, nih. polyomaviruses are small dna tumor viruses that depend on the host cellular dna polymerase for their replication. three polyomaviruses have been associated with tumor formation in humans: jc virus (jcv), bk virus (bkv) and simian vacuolating virus (sv40). in addition, some of them have been associated with viral diseases. jcv can cause progressive multifocal leukoencephalopathy in immunosuppressed patients, while bkv is considered to be the causative agent of polyomavirusassociated nephropathy, which leads to kidney transplant failure. sv40 has not been associated with a well-defined disease, but viral dna sequences and protein expression have been detected mostly in central nervous system (cns) tumors which strengthens the evidence for the association of this virus with human cancer. the activity of various acyclic nucleoside phosphonates (anps) such as cidofovir and adefovir against murine polyomavirus and primate sv40 in vitro has already been demonstrated (andrei et al., 1998. antimicrob. agents chemother. 41, 587-593) . here, the activity of a new class of anp's, namely 6-[2-(phosphonomethoxy)alkoxy]-2,4diaminopyrimidines, against polyomaviruses was assessed. confluent uc1-b cells were infected with either of the four murine polyomavirus strains mn/rde toronto, pta, 2pta2 or lid-1, while bsc-1 cells were infected with either the primate sv40 strain a2895, the sv40 pml-1 strain ek or the sv40 pml-2 strain dar. after removal of the residual virus, serial dilutions of the test compounds were added. the viral cytopathic effect was recorded microscopically after 4-6 days (murine polyoma virus) or 5-7 days (sv40). hpmpo-dapy (2,4-diamino-6-(r)-[3-hydroxy-2-(phosphonomethoxy)propoxy]pyrimidine) and pmeo-dapy (2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidine) were less active/selective than cidofovir and adefovir against the three sv40 strains tested. hpmpo-dapy and pmeo-dapy proved to be equally active as cidofovir and adefovir against the murine polyomaviruses. naresh sunkara 1 , sylvester mosley 1 , brian bakke 1 , joshua sadler 1 , katherine seley(radtke) 1 , sunny zhou 2 1 university of maryland-baltimore county, baltimore, md, usa; 2 washington state university, pullman, wa, usa inhibition of biologically significant enzymes critical to nucleotide metabolism and viral replication is a well-established chemotherapeutic approach to the treatment of many diseases. transcriptional 5 -capping of viral mrna has been implicated as an "elongation checkpoint" critical to the replication cycle of many viruses. this capping process is accomplished by various methyltransferases, therefore disruption of methylation becomes an attractive target for therapy. this can be accomplished in several ways; in particular, by direct inhibition of methyltransferases (metase) and/or indirect inhibition of s-adenosyl-l-homocysteine hydrolase (sahase), both established cellular targets for antiviral, antiparasitic and anticancer agents. modified nucleosides, in particular carbocyclic nucleosides, have exhibited potent inhibitory activity against both sahase and metase. inspection of the recent literature has revealed a close correlation between sahase inhibition and potent biological activity against negative stranded (−)-rna viruses (i.e. arenaviridae, paramyxoviridae, rhabdoviridae), double stranded (ą)-rna viruses (reoviridae), poxviridae, as well as hiv-1, thus supporting the importance of sahase as a viable chemotherapeutic target. herein we report the design, synthesis, and preliminary biological activity of a new class of structurally novel carbocyclic nucleosides. phosphorylation of ␣-p-borano substituted nucleoside diphosphates charlotta wennefors, mikhail dobrikov, barbara ramsay shaw chemistry department, duke university, durham, nc 27708-0346, usa most nucleoside antiviral agents require stepwise phosphorylation to their respective triphosphates in order to be activated in the cell. ␣-p-borano substituted nucleoside triphosphates are of interest because they have proven to be good substrates for hiv-1 reverse transcriptase (rt) and may therefore be useful antiviral agents. studies in our laboratory have indicated that the ␣-p-borano substitution of 2 3 -dideoxycytidine triphosphate (ddctp) resulted in a 28-fold increase in efficiency of incorporation by mmlv rt compared to non-substituted ddctp. however, the potency of these ␣-p-borano substituted nucleoside analogs as anti-viral drugs highly depends on their ability to be activated to nucleoside triphosphate (ntp). the phosphorylation of nucleoside analog diphosphates to their respective triphosphates has remained largely unexplored. here, the roles of several phosphorylating enzymes are examined. in our laboratory, nucleoside diphosphate kinase, creatine kinase, and pyruvate kinase are being evaluated for their specificity towards nucleoside analog diphosphates. the effects of nucleobase, ribose, ␣-phosphate substitution and stereochemistry of the boranophosphate group are of interest. the binding affinities of the substrates for creatine kinase (ck) and pyruvate kinase (pk) were determined using a fluorescence-quenching assay, which allowed us to investigate the substrate affinity in the pre-steady state. rabbit muscle ck and pk were titrated with a wide range of ndps and ntps by monitoring a decrease in enzyme intrinsic fluorescence. the affinities of these substrates were determined to establish a structure-activity relationship for ck and pk and to evaluate the effect of a substrate ␣-p-borano modification. ck showed stereospecificity towards the sp isomer of adp␣b whereas pk showed stereospecificity towards the rp isomer of adp␣b. negative cooperativity was observed for all studied substrates. steady-state experiments are also being performed directly following the product formation using uv-visible spectroscopy and high performance liquid chromatography (hplc). these kinases were investigated because they may serve as a means for activation of antiviral ␣-p-borano substituted ndps. traditional antiviral targets encoded by the small human papillomavirus (hpv) genome are lacking. for this reason, we chose to target dna sequences within the hpv genome in an effort to identify compounds that would block viral dna replication in cells. we chose compounds known as polyamides, which are related to distamycin and other natural products, as our dna binding agents. unlike many literature studies where polyamides were designed to block formation of the transcription complex for a particular gene, we chose to target sequences within the origin of replication (ori). thus, pyrrole-imidazole polyamides, with some containing fluorescent probes to aid in cell localization studies, were designed to recognize the hpv31 ori. the principles used to design these compounds will be described. we used "traditional" hairpin polyamides and some more unusual structures related to very recent literature reports. from the focused library that we prepared, two highly active molecules were identified. the rest of the molecules had minimal or zero activity. no cellular toxicity was observed, either in this project or in a related program where polyamides were used to affect cox-2 transcription (and subsequent expression) in rheumatoid synovial fibroblasts. of particular interest is the difference between the active molecules and two closely related compounds that were inactive: the active species bind and recognize two more hpv dna base pairs than do the related but inactive structures. this presentation will provide detailed chemistry background and structural information to complement our cell work that is also being presented at the meeting. discovery of the chemokine receptor ccr5 as a co-receptor for hiv-1 infections revealed a novel approach to hiv-1 treatments and preventions. ccr5, a member from the family of 7tm g-protein coupled receptors, thus became an attractive target pursued in the pharmaceutical industry. with the recent successful developments of several small molecules in clinic, these ccr5 antagonists hold great promise to be the next generation of anti-hiv medicines. this poster will describe our efforts at the n-terminal piperidine ring of template a to improve pharmacological properties of derived molecules. according to current models, proteolytic processing of hiv-1 gag precursor occurs within the virions which detach from infected cells. meanwhile, the viral protease is activated much earlier, and gag p55 cleavage initiates in infected cells. we followed the fate of matrix protein cleaved in infected cells (cma) in comparison with ma cleaved in the virions (vma) and showed that both forms differ in their localization in the infected cells and in the virions, both forms are involved into virus pathogenesis and represent the targets for antiviral compounds. mt-4 cells were labeled with [3h]-leucine or myristic acid, and 2 h after labeling protease inhibitor was added to separate the cleavage of cma from vma. cma was found in the nuclear and membrane fractions of infected cells while cca resided in cytoplasm. 18-20 h after labeling cma was found in the virions localizing in the cores. vma was located under lipoprotein envelope of the virions. new membranotropic antiviral compounds based on adamantane-and norbornene-related derivatives not toxic for the host cells were added to mt-4 cells before infection or 1-2 h later and at concentration 2-6 ug/ml blocked reverse transcription, the transport of cma into the nuclei, and the production of infectious virus. the compounds inhibiting very early step of virus life cycle are optimal candidates for microbicides. to enhance their antiviral activity, we plan to associate polyanionic matrix with ma imitating peptides and cholesterol-like fragments. kurt vermeire 1 , thomas bell 2 , sreenivasa anugu 2 , noah duffy 2 , roger le grand 3 , erik de clercq 1 , dominique schols 1 1 rega institute for medical research, katholieke universiteit leuven, leuven, belgium; 2 department of chemistry, university of nevada, reno, usa; 3 service de neurovirologie, fontenay-aux-roses, france the cyclotriazadisulfonamide (cada) compounds were shown to be potent inhibitors of hiv replication in human t-cell lines, pha-stimulated pbmcs, and monocytes/macrophages (ec 50 : 0.3-3.2 m). the prototype compound, cada, had consistent activity against laboratory adapted and primary clinical isolates of hiv-1, irrespective of chemokine receptor preference (r5, x4, r5/x4). cada acted synergistically when evaluated in combination with various other hiv drugs, such as reverse transcriptase (rt), protease, and virus entry inhibitors. flow cytometric analysis revealed a significant decrease in the cell surface and intracellular expression of the cd4 receptor in human cells after cada-treatment. moreover, the anti-hiv activity of cada correlated with its ability to down-modulate the cd4 receptor in human t-cells. here, we report the consistent antiviral activity of cada against: (i) drug-resistant viruses (i.e. viruses resistant to rt inhibitors, protease inhibitors, and enfuvirtide); (ii) different hiv-1 subtypes (a, b, c, d, a/e, f, h, o); and (iii) various hiv-2 strains examined. in addition, cada potently inhibited sivmac251 infection of pbmcs isolated from macaques (ec 50 : 1.6 m). comparable results were obtained in human cells infected with sivmac251. flow cytometric analysis also demonstrated a significant and dose-dependent down-regulation of the cd4 receptor expression at the cell surface of simian pbmcs after treatment with cada. the combination of cada with cellulose acetate 1,2benzenedicarboxylate (cap), an enteric coating polymer for capsules and tablets, resulted in a synergistic antiviral activity. in summary, our data indicate that cada may qualify as a potential anti-hiv microbicide drug candidate for the prevention of the sexual transmission of hiv. the preparation of gel formulations of cada (as single drug and in combination with cap) for vaginal administration in non-human primates is currently under investigation. department of micro & immuno, suny upstate medical university, syracuse, ny, usa varicella zoster virus (vzv, human herpesvirus 3) infection causes chicken pox, latency is established in neurons, and reactivation leads to shingles. acyclovir and its derivatives are the treatment of choice for both manifestations of vzv. new therapeutics are needed because acyclovir-resistant strains exist, and treatment must begin within 48 h. we have studied the anti-vzv properties of roscovitine, a cyclin dependent kinase (cdk) inhibitor. here, we tested more compounds that block the cell cycle and determined that vzv is acutely sensitive to them. their effects on vzv replication were tested in human foreskin fibroblasts (hffs) because these primary cultures should have a normal cell cycle (unlike tumor cell lines). the cytotoxicity of the drugs was determined by neutral red dye uptake assays. hffs were inoculated with a low moi (0.01) of vzvinfected cells, which remains entirely cell-associated, and then treated with drugs or diluent for 48 h. vzv spread and replication were measured by infectious focus assay and quantitative real time pcr. all of the drugs tested (acyclovir [acv], phosphonoacetic acid [paa], aphidicolin, aloisine a, purvalanol a, roscovitine, r-roscovitine, s-roscovitine, indole-3-carbanol [i3c], l-mimosine, dichloro-␤-d-ribofurano-sylbenzimidazole [drb]) had some anti-vzv activity. the selective indices of aphidicolin (833), purvalanol a (570), and i3c (1000) were greater than the positive controls acv (250) and paa (60). aphidicolin inhibits mammalian dna polymerase and is in clinical use for cancer; purvalanol a, a 2,6,9-trisubstituted purine, primarily inhibits cdk1; and i3c is derived from cruciferous vegetables and inhibits cell proliferation. the concentrations of these compounds that inhibited vzv replication were much less than those needed to cause cell cycle arrest, suggesting that vzv depends on the enzyme activities targeted by these compounds and not on cell proliferation per se. these three drugs will be studied next in skin organ culture and in the scid-hu mouse model of vzv pathogenesis. the results presented here demonstrate that targeting cell functions can inhibit vzv replication and help us better understand virus-host interactions. the viruses could be identified as supra-biopolymeric nanoscale complexes, parasitic intervention in cells of which occurs on an inter-polymeric reactions level. so the antiviral safety can not be fully provided without adequate nano-responsible antivirals (nav). here we discuss a strategy and methodology for the multi-functional nav development by rational macromolecular sar-cooperation of: (1) polyelectrolyte-specific interferon induction and immunomodulation; (2) electrostatic-selective prevention of viruses absorption on plasma membranes; (3) membrane-targeted blocking of post-absorption steps (fusion); (4) macromolecular prevention of structure-specific interactions of viral and cellular receptors; as well as (5) polymericassociated disruption of the latest stage of viral replication (virions assembly and maturation). a cooperation of the (1) and (2) functions was explored by synthesis and sar-optimization of succinate and carbohydrate polymeric derivatives modified with controllable combinations of anionic (a1/a2) groups. the immune-mediated protectors against tick-born, rabies, and other viral infections in vivo, and hiv-1 absorption inhibitors in vitro, were developed. this pre-nav generation was used as a macromolecular platform to step-by-step targeted design and synthesis toward high effective multi-functional nav where virusresponsible nano-selectivity was achieved by rational intra-or inter-molecular cooperation of virus-specific membranotropic vectors (bi), raft-targeted anchors (ci), and peptide-kind mimickers of virus usable receptors of human cells (pi), particularly ccr5/cxcr4. as a result, the novel nano-sensitive systems possessed unique wide multi-synergistic antiviral potency on a high level selectivity up to si = 20,000 (against hiv-1 strains) were created and purposed for advancement of antiviral vaccines, drugs, and microbicides. marina kukhanova 1 , alexander ivanov 1,2 , georgii galegov 3 , valeria andronova 3 , maxim jasko 1 1 engelhardt institute of molecular biology, russian academy of sciences, moscow, russia; 2 centre for medical studies, university of oslo, moscow, russia; 3 ivanovsky institute of virology, russian academy of medical sciences, moscow, russia novel acyclic purine phosphonate derivatives bearing a double bond conjugated with the nucleic base, namely, (z)-and (e)-9-[3-(phosphonomethoxy)prop-1-en-1-yl]purines, were synthesized, and their efficacies against hiv-1 and hsv-1 were evaluated in cell cultures. the activity of (z)isomer was higher against hiv than that of the reference 9-[2-(phosphonomethoxy)ethyl]adenine (adefovir) and comparable in respect to the activity of adefovir against hsv. the (e)-isomer showed low antiviral activity against both viruses. the compounds were less toxic towards cell cultures if compared to adefovir. the diphosphates (z)-and (e)-9-[3-(phosphonomethoxy)prop-1-en-1-yl]purines were evaluated as substrates towards hiv-1 reverse transcriptase and hsv dna polymerase. (z)-isomer was shown to be a more efficient substrate for both enzymes than the (e)-isomer. human dna polymerase alpha could incorporate neither of the diphosphates into the 3 -end of the growing dna chain. available to this virus. jev genome is an approximately 11-kb single-stranded positive-sense rna that has a cap structure at its 5 terminus but lacks a poly(a) tail at its 3 -terminus. the coding region of the genome is flanked by 5 -and 3 -untranslated region (utr). the 3 -utrs on both plus-and minus-strand jev genome contain important cis-acting elements required for the replication of the viral rna genome. peptide nucleic acid (pna) is a synthetic oligonucleotide, in which the phosphodiester backbone of dna/rna is replaced with a polyamine-(2-aminoethyl) glycine skeleton. pna offers a potentially powerful approach for recognition of rna and silencing of gene expression. in this study, we investigated the antiviral effect of the pnas targeted to the 3 -utr region of jev genome. to evaluate the pnamediated inhibitory effect on rna synthesis in vitro, the rnadependent rna polymerase (rdrp) of jev, ns5 protein, which plays a major role in replication of the viral genomic rna, was expressed in escherichia coli and purified to near homogeneity by sequential column chromatographies. the recombinant jev ns5 protein exhibited a primer-dependent rdrp activity in vitro on a homopolymeric template, poly(a). in addition, it was able to accept both plus-and minus-strand 3 -utrs as templates for rna synthesis in the absence of an exogenous primer. it could utilize the 3 -end 83-nt of jev genome as a minimal template. in vitro rdrp assays using this functional recombinant jev rdrp in the presence of the pnas targeted to the jev 3 -utr 83-nt showed a dose-dependent rna synthesis inhibition. delivery of the inhibitory pnas to the jev-infected cells suppressed jev replication, as determined by western-blot analyses and plaque assays. our results showed a sequence specific inhibition of jev replication by antisense pnas, suggesting the possible application of pna as a novel anti-jev agent. julia serkedjieva 1 , reneta toshkova 2 , milena nikolova 3 , reneta tsvetkova 3 , stefka antonova 4 , ivana roeva 1 , munnever sokmen 5 , bektas tepe 5 , medine gulluce 6 , fikrettin sahin 6 , atalay sokmen 5 1 institute of microbiology; 2 institute of experimental pathology and parasitology; 3 institute of botany, bulgarian academy of sciences; 4 faculty of biology, department of microbiology, sofia university, sofia, bulgaria; 5 faculty of art and science, department of biology, cumhuriyet university, sivas, turkey; 6 faculty of art and science, department of biology, atatürk university, erzurum, turkey natural products can be an important source of new pharmaceuticals. research on antivirals of natural origin is mainly focused on plants, since, among other reasons, they can be selected on the basis of their ethnobotanical use. plant extracts and natural plant products exhibit also a variety of biological activities with pharmacophoric utility. the population of the balkan peninsula, like people from all continents, has long applied poultices and imbibed infusions of hundreds of indigenous plants. the present report summarizes the antiviral screening study of 134 plant products, obtained from 67 bulgarian and turkish medicinal plants. they were tested for inhibitory effect on the reproduction of selected influenza virus (flu) strains in mdck cells and herpes simplex virus (hsv) strains in mdbk cells. the reduction of virus-induced cpe and infectious virus yields were used as measures of viral inhibition. fifteen samples (11.2%) inhibited flu reproduction, and twelve samples (7.5%) were active against hsv. the anti-flu activity was confirmed in vivo for all tested samples. the most effective products were tested further for their antiproteolytic, antioxidant and immunogenic capacities and for potential antibacterial and antifungal effects. the following correlations among the variety of biological and pharmacological activities of the plant products were observed: the anti-flu effect was associated with anti-hsv effect and vice-versa in 55.5%; the antiviral effect was connected with antioxidant activity in 100%; the anti-flu effect was associated with immunogenic properties in 100%; there was found no correlation between the antiviral effect and the antiproteolytic capacity, the anti-viral properties and bacterial or fungal inhibition, the anti-viral activity and the polyphenol contents. our previous investigations have revealed antiviral activity of some proteolysis inhibitors such as e-aminocaproic acid (e-aca) and para-aminomethylbenzoic acid (pamba) in vitro, in vivo and in clinic. construction of qsar computer-assisted hierarchical system for the effective anti-herpetic (anti-hsv) and anti-influenza (anti-flu) agents' selection as well as the elaboration of new methods of their synthesis are permanently the object of keen interest of our team. the objective of this study was to investigate the efficacy 2,6-di-substituted pyridines and their analogs combined with the fragments of proteolysis inhibitors in the framework of the qsar approach. molecules of new compounds consisted of "nucleus" (py or ar) and two symmetrical fragments: e-aca-carbonyl or pambacarbonyl taken from the inhibitors' molecules. anti-flu activity in dose 10-3 m was studied in vitro on the model of a/hong kong/1/68 (h3n2) reproduction in tissue cultures of chorioallantoic membranes of 12 days old chick embryos. anti-hsv activity in doses 10-4 m was studied on models of reproduction of hsv-1 on cell culture hep-2. compounds with py-nucleus, contained pamba-carbonyl or e-aca-carbonyl fragments, demonstrated sufficient anti-hsv activity (39.4 and 61% of reduction of intra-nucleus virus-specific inclusions on infected cells account accordingly). 3,5-dihydrazine-carbonyl-2,6-dimethylpyridine showed high anti-hsv (52%) activity. the efficacy of the designed antiherpetic compounds obtained with the combined efforts of qsar computer-assisted design, properties prediction, synthesis, and biological testing as well as the correction introduced after the iteration circle passsage have proven to be the efficient modern way of drug design. acknowledgement: this research was supported in part by stcu grant # 3147 and all the authors are indebted to stcu foundation courtesy. lubomira nikolaeva-glomb 1 , angelina trifonova 1 , stephan filipov 2 , angel s. galabov 1* 1 institute of microbiology, bulgarian academy of sciences, sofia, bulgaria; 2 institute of organic chemistry, bulgarian academy of sciences, sofia, bulgaria a series of aporphinoid alkaloids isolated from glaucinum flavum l. or obtained synthetically, were tested in vitro for antiviral activity against viruses belonging to picorna-, orthomyxo-, paramyxo-and herpesviruses. one of them, oxoglaucine, manifested a well-pronounced inhibitory effect on poliovirus 1 replication in fl cells measured by the semi-quantitative agardiffusion plaque-inhibition test. in virucidal activity testing the compound did not show direct virucidal effect on the extracellular virus. oxoglaucine's 50% inhibitory concentration for poliovirus 1 (mahoney) was found to be 0.188 g/ml in the cpeinhibition test and 0.041 g/ml in the classical plaque-inhibition test. similar values were obtained for the vaccinal poliovirus type 1 strain, lsc-2ab. the antiviral effect of oxoglaucine on the replication of viruses belonging to another enterovirus species was tested, i.e. coxsackie and echoviruses (hev-b). cva-9, the six coxsackie b viruses and 6 echoviruses were tested for their sensitivity against the antiviral effect of oxoglaucine by the endpoint dilution method in the multi-cycle cpe inhibition set-up in fl cells. oxoglaucine revealed a marked inhibitory effect on all tested enteroviruses. the concentrations that reduced virus titer by 1 lg ranged from 0.01 to 1.0 g/ml. selectivity index was greater than 100 and even greater than 1000 for some of the viruses tested. time-of-addition study by the one-step virus growth cycle set-up showed strong virus inhibition during the early periods of virus replication. milka mileva 1 , angel s. galabov 2 1 department of medical physics and biophysics, medical university, sofia, bulgaria; 2 institute of microbiology, bulgarian academy of sciences, sofia, bulgaria in this study an investigation and comparison of the effects of plant flavonoid polyphenols quercetin and its sugar-containing homologue (rutinoside) rutin on the "oxidative stress" in liver, isolated from influenza virus a/aichi/2/68 (h3n2) (2.0 of ld50) inoculated mice, is carried out. it was found that experimental influenza virus infection is accompanied with graduated oxidative disturbances in the liver of mice, despite the absence of virus and inflammation in this tissue. it was found that experimental influenza virus infection is accompanied with a significant increase of lipid peroxidation products, a decrease of natural antioxidants (vitamin e, glutathione) and cyp, an inhibition of cytochrome c-reductase and liver monooxygenases (analgin-ndemethylase and amidopyrine-n-demethylase) as compared to control (non-infected) animals. the preliminary (5 days) supplementation of mice with rutin, quercetin or its combination, and their subsequent virus inoculation influence significantly all analyzed parameters as compared to controls. the protective effect of rutin against influenza virus-induced lipid peroxidation and activities of cyp and liver monooxygenases in liver was better expressed than the effect of quercetin may be due to containing of rutinoside part or difference of its metabolism. hyun-jeong lee 1 , ji-sun kwon 1 , chi-ung moon 2 , jong-hwan kwak 3 , youn-jeong lee 4 , chang-seon song 1 1 avian disease laboratory, college of veterinary medicine, konkuk university, seoul, korea; 2 hanyang university, seoul, korea; 3 sungkyunkwan university, seoul, korea; 4 national veterinary research and quarantine services, seoul, korea one of the traditional korean medical herb extract named s22 was investigated to determine the anti-influenza virus activity in vitro and in vivo. the s22 showed potent antiviral activities against a/pr/8/34 (h1n1) influenza virus with the 50% effective concentration (ec50) values of 62.5 g/ml and the 50% cytotoxic concentration (cc50) values of 673.86 g/ml in mdck cells. treatment with the s22 appeared capable of significantly ameliorating the influenza virus infection in mice by oral gavage treatment. the s22 treated mice showed significantly higher survival rate and lower pathogenic index as well as lung virus titers than untreated control mice. further, the s22 was extracted with chcl3, etoac and n-buoh for isolation of active compounds. the anti-influenza effects of these active compounds will be discussed. the antiviral effect of aqeous and ethanol extracts of ocimum gratissimum (og), terminalia catappa (tc), gynostemma pentaphyllum (gp), newbouldia laevis (nl), aspilia africana (aa) and phyllantus amarus (pa) leaves was examined by cultivation of virus and extracts in embryonated chicken eggs. extracts were inoculated immediately after virus (zero time) or 2 h after virus inoculation. virus replication was compared with those of controls by haemagglutination assay. at zero time, aqeous extracts of og, tc, pa, and gp inhibited virus growth by 50, 61, 72, and 94%, respectively whereas those of nl and aa did not. ethanol extracts of og, tc, pa and gp at same time inhibited by 25, 100, 72, and 100%, respectively whereas nl and aa did not. at two h after virus inoculation aqeous extracts of og, tc, pa and gp inhibited virus growth by 92, 6, 67, and 100%, respectively whereas nl and aa had no effect. ethanol extracts of tc, pa and gp inhibited the virus by 94, 78, and 94%, respectively whereas those of og, nl, and aa did not. the herbs were studied because they were being used by some herbalists in the treatment of human infectious diseases. the 20th international conference on antiviral research will be held in the palm springs, california area. the conference will begin on sunday, april 29, 2007 and will end on thursday afternoon, may 3, 2007. all scientific sessions will be held at the westin mission hills resort, rancho mirage, ca. the purpose of the international conference on antiviral research is to provide an interdisciplinary forum at which investigators involved in basic, applied, and clinical research worldwide can meet to review recent developments in all areas of antiviral research. specific topics to be covered in the program include synthesis and chemistry, biochemistry and mechanism of action, molecular biology and drug targeting, in vitro evaluation, animal models, pharmacokinetics, toxicology, and clinical trials. within these areas of interest, there will be invited overview speakers, oral presentations, and poster presentations. the famous el paseo shopping district of palm desert and downtown palm springs offer not only a large variety of galleries, boutiques and shops too numerous to mention, but there are restaurants for virtually every palate. whether your tastes run to burgers, sushi, pizza, escargot, steak, mexican or continental you will find it here with a california flourish in every price range. we hope you will take advantage of this opportunity to combine an important learning experience with a magnificent travel experience and join us in palm springs, california for the 20 th international conference on antiviral research. isar conference committee future conferences acknowledgement: the study was supported by rfbs 05-04-49500 and russian ministry of sciences (lot 11). key: cord-004948-ad3i9wgj authors: nan title: 7th international congress on amino acids and proteins : vienna, austria, august 6–10, 2001 date: 2001 journal: amino acids doi: 10.1007/s007260170030 sha: doc_id: 4948 cord_uid: ad3i9wgj nan the raised concentration of protein bound homocysteine in homocystinuric (hcu) patients displaces protein bound cysteine and increases the free/bound cysteine ratio in plasma. this ratio is independent of albumin concentration. results from 31 hcu patients were compared to 40 controls. free cystine concentrations in hcu were poorly discriminated from the control range but the total cysteine results were almost invariably lower than control data. this appears to result from an increased free/bound cysteine ratio in hcu [mean (range) for control 0.50 (0.22-0.71) and for hcu 0.76 (0.32-1.75); p ϭ 0.0005]. ex vivo protein binding experiments in albumin solution revealed the free/bound cysteine ratio to be linearly related to the amount of homocysteine bound (r ϭ 0.907, p ͻ 0.001). we conclude that measurement of total cysteine is essential for assessment of the true cysteine status in hcu. however, any cysteine deficit, or alteration to free/bound cysteine ratios, does not obviously effect glutathione synthesis as assessed by measurement of plasma total glutathione. (339 nmol/g; 21.6%); sprague-dawley rat (rattus norvegicus, rodentia) (n ϭ 6; 98-381 nmol/g; 9.8-13.7%); rabbit (152 nmol/ g; 11.3%); pig (sus scrofa f. domestica, artiodactyla) (221 nmol/ g; 13.4%); bovine (bos primigenius f. taurus, artiodactyla) (284 nmol/g; 23.6%); seal (phoca vitulina, carnivora) (136 nmol/g; 3.8%), and rob (halichoerus grypus, carnivora) (218 nmol/g; 5.4%). from the date it is concluded that d-aas are common in body fluids and certain tissues of vertebrates. in order to determine the quantity of cyst(e)ine and methionine, the oxidation of cyst(e)ine and methionine (ϫ) refers to not detected or not determinable; asx ϭ asp ϩ asn; glx ϭ glu ϩ gln; his, arg, trp, cys not determined; a) feed fortified with dl-met; b) nmol/g lyophilized serum. mentation and subsequent purification. the separation of the enantiomers of cysteic acid, methionine sulphone, aspartic acid and glutamic acid is displayed on the chromatogram. into cysteic acid and methionine sulphone with performic acid is often applied before hydrolysis of protein. the authors examined the applicability of this process in case of quantification of cyst(e)ine and methionine enantiomers. the rp-hplc analytical method was developed for the determination of the amount of cysteic acid and methionine sulphone enantiomers. the rate of conversion during oxidation from cyst(e)ine into cystic acid and from methionine into methionine sulphone was determined. the racemisation of l-cyst(e)ine and l-methionine was negligible during oxidation with performic acid, therefore this process can be applied before hydrolysis during quantification of cyst(e)ine and methionine enantiomers. after the performic acid oxidation and the 6 m hcl hydrolysis of the protein, opa/tatg (o-phthaldialdehyde/tetra-o-acetyl-1-thio--d-glucopiranoside) precolumn derivatisation method was used, and the enantiomers of sulphur containing amino acids were separated by rp-hplc (lichrosphere 100 rp-18e, 125 ϫ 4 mm, 5 µm column, merck-hitachi lachrom hplc). the resolution of the peak of cysteic acid and methionine sulphone enantiomers was better than 1,5. the method was used to determine the amount of l-and d-cyst(e)ine and land d-methionine containing preparations prepared by ferd/l rate of aspartic acid and the individual age of specimens. a method for age determination based on d-aspartic acid content and on the racemisation of l-aspartic acid of teeth was developed. d-glutamic acid, beside d-aspartic acid, was found to be eminently suitable for the estimation of individual age, as it showed a sufficiently high sensitivity. calibration curves based on these investigations were used for the age estimation of 65 adults (39 males and 26 females) of unknown individual age from the avar period series of kereki-homokbánya (hungary). the age distribution of the sample was the following: 39 individuals (60%) belonged to the adult age group, 22 persons (34%) to the mature and 4 (6%) to the senile one. the correlation between our results and those obtained using standard paleoanthropological methods was over 0.9. quantitative determination of free and bound 3-nitrotyrosine in rat plasma and tissues using isotope dilution liquid chromatography-electrospray tandem mass spectrometry t. delatour, p. a. guy, j. richoz, j. vuichoud, and nestlé research centre, nestec ltd, vers-chez-les-blanc, lausanne, switzerland since 3-nitrotyrosine was reported to be readily formed in proteins by reactions with nitrite or nitrogen dioxide, it has been postulated to be a possible marker for investigating peroxynitrite-mediated nitration of proteins. thus, several methods were developed to assess nitration of tyrosine in proteins and determine 3-nitrotyrosine in physiological fluids. methods based on hplc or gc/ms techniques were described to quantify 3-nitrotyrosine within tissues or biological fluids. unfortunately, it has been demonstrated that an artifactual nitration of tyrosine occurs with gc/ms assays leading to an overestimation of the response. in the present work, lc-esi-ms/ms methods for quantification of free 3-nitrotyrosine in rat plasma as well as bound 3-nitrotyrosine in tissue samples are reported. plasma samples were spiked with 2,5,6-d 3 -3-nitrotyrosine and the following steps were applied prior to injection into the lc-esi-ms/ms system used in selected reaction monitoring (srm) mode (m/z 283 ae 181 for the analyte and m/z 286 ae 184 for the internal standard): protein precipitation, solid phase extraction on aminopropyl cartridge and derivatization in nbutanol in hcl 3 n. 3-nitrotyrosine butyl ester has lead to a dramatic increase of the sensitivity (ca. 5-fold) by comparison with 3-nitrotyrosine. under such conditions, calibration curves exhibited excellent linearity (r 2 ͼ 0.99) within concentration range 0.3 to 28.5 nm (equivalent to 47.3-4,730 fmol on column) and recoveries above 85%. inter-and intra-assay precision was determined below 15% over the concentration range 1.4 to 28.5 nm. no artifactual nitration of tyrosine occurring during sample clean-up was observed. this was unambiguously established by plotting experimental ratio of analyte response/ internal standard response versus expected within the range 0.3-28.5 nm. this curve strongly correlated with a linear model (r 2 ͼ 0.99) and slope was 1.07 ϯ 0.06 (mean ϯ sd). basal level of 3-nitrotyrosine in rat plasma was measured to be within concentration range ͻ lod to 1.5 nm. 3-nitrotyrosine basal level in rat plasma, kidney and liver proteins was established by performing enzymatic hydrolysis in order to avoid artifactual nitration of tyrosine which may occur under strong acidic conditions (hcl 6 n at 120°c). resulting hydrolysates were analysed by lc-esi-ms/ms and 3nitrotyrosine was monitored in srm mode (m/z 227 ae 181 for the analyte and m/z 230 ae 184 for the internal standard). t. guszczynski 1 , r. b. kapust 2 , d. s. waugh 2 , and t. d. copeland 1 1 basic research laboratory, and 2 macromolecular crystallography laboratory, national cancer institute at frederick, maryland, u.s.a. the set-can fusion gene was first detected as associated with acute undifferentiated leukemia. set (also called phap ii) is a nuclear phosphoprotein with a long acidic tail. set has been shown to inhibit phosphatase pp2a and is a substrate of human granzyme a. in order to determine any zn(ii) binding properties of set, we utilized affinity capillary electrophoresis (ace) to detect shifts in mobility as zn(ii) ions bind to the protein. we have earlier employed ace to measure the binding constants of zn(ii) to the nucleocapsid protein of hiv-1. with a constant concentration of recombinant set as a receptor and varying concentrations of zn(ii) as ligand in the sample buffer, we observed changes in electrophoretic mobilities of set when complexes were formed with zn(ii). scatchard analysis of the mobility provided the stoichiometry and binding constant of zn(ii) to set. interdisciplinary research center, institute of nutritional science, department of food sciences, university of giessen, germany peptaibols are defined as fungal polypeptides containing a high proportion of aib (α-aminoisobutyric acid) and a cterminal bound amino acohol. the mold trichoderma aureoviride (strain imi 91968; commonwealth mycological institute, kew, uk) was cultured in complex medium consisting of casein peptone, 17 g; soy peptone, 3 g; yeast extract, 5 g; dglucose, 2.5 g; nacl, 5 g; dipotassium hydrogen phosphate, 2.5 g in 1 l demineralized water adjusted to ph 6.8. fermentation was conducted in nineteen 2-l shake flasks, each containing 400 ml medium, for 7 d at 27°c. mycelia were obtained by filtration and extracted with meoh and meoh/chloroform. extracts were evaporated to dryness and subjected to sephadex and silica gel chromatography (eluent chloroform/meoh/acoh/water 65 : 25 : 3 : 4) yielding 2.83 g and 0.9 g, respectively, crude peptaibol mixture named trichoaureocins. the peptide mixture was uniform on tlc but could be separated by analytical (fig. 1 ) and semipreparative hplc (nucleosil 100 c-18; 250 ϫ 8 mm id; 3 µm). six peptides could be isolated each of which was subjected to sequencing using on-line hplc (fluorocarbon stationary phase) esi-ms/ ms (lcq, thermoquest, finnigan mat) as described for peptaibols trichovirins and antiamoebins. sequences are presented in fig. 2 . the 20-residue peptaibols represent a natural peptide library and cause hemolysis of sheep erythrocytes and exert antibiotic activity against bacillus subtilis and staphylococcus aureus. national institute of chemistry, ljubljana, slovenia wine consists of several hundred components present at different concentrations. the dominant ones are water, ethanol, glycerol, sugars, organic acids, and various ions, while amino acids are present at much lower concentration. the composition of amino acids is of great importance in wine production. they act as a source of nitrogen for yeast during fermentation, they influence the aromatic composition of wine and their composition can be used to differentiate wines according to vine variety, geographical origin, and year of production. among already established analytical methods high-field nmr has been shown to be a promising method for the nondestructive analysis of low-molecular mass compounds in complex mixtures like wine due to its selectivity and capability of simultaneously detecting a great number of compounds. 1 h and 13 c one-dimensional nmr spectra of wine are very crowded and many signals are overlapped. due to a great difference in concentration levels the signal intensities of particular compounds may vary for the factor of 25. the tails of the dominant frequencies of water, ethanol and glycerol obscure weak signals of minor compounds like amino acids in the near surroundings. the use of 2d homo-and heteronuclear experiments and the suppression of strong signals are a prerequisite for a successful 1 h and 13 c signal assignment. a complete assignment of 1 h and 13 c nmr resonances of seventeen amino acids commonly present in wine and of γ-aminobutyric acid at ph 3 was accomplished using gradient-selected cosy, tocsy, gradientselected hsqc and hmqc experiments with incorporated wet pulse sequence for the supression of large signals. unambiguous assignment of 1 h and 13 c nmr resonances of amino acids is necessary for the selection of appropriate signals in fast and simple one-dimensional nmr that can serve as parameters in the chemometric classification of wines according to the provenance, vine variety, and year of production. institute of medical biochemistry, jagiellonian university collegium medicum, kraków, poland highly sensitive colorimetric method for determination of aldehydes in the reaction with n-methyl benzothiazolone hydrazone (mbth) turned out to be not very specific for such carbonyl compounds. namely, it has been found that tryptophan and to higher degree its n-derivatives (n-acetyl-trp, ala-trp, gly-trp) and also tripeptides (gly-trp-gly and leu-trp-leu) in the reaction with mbth and fe 3ϩ are converted to coloured products, with maximum wavelength at 595 nm. the properties of the products and the kinetics of the reaction under defined conditions are described in the spectrophotometric procedure. proteins containing tryptophan are also substrates in the reaction with mbth. comparison of molar extinction coefficients of mbth-fe 3ϩ -treated various proteins with those of simple n-derivatives of tryptophan shows, that not all molecules of tryptophan in proteins are accessible to the reagents, and in order to determine all tryptophan moieties partial unfolding of protein has to be performed. it should be emphasized that aldehydes cannot be detected and accurately determined in the presence of tryptophan derivatives and protein, and also aldehydes interfere with determination of tryptophan derivatives. natural product laboratory, department of chemistry, the university of burdwan, w. bengal, india detection of protein amino is of utmost importance for the evaluation of protein structure and also their presence in numerous natural products. several specific and non-specific reagents have been used for their detection using thin-layer chromatography, an important tool for such purpose. of the reagents in general use, ninhydrin is the most popular for its high sensibility, however, nihydrin produces same purple color with most of the amino acids (only proline and hydroxproline produce yellow color). an endeavour has been made to resolve this color problem with a reagent which is capable of developing various distinguishable colors with many of the protein amino acids and also shows its high sensitivity comparable to ninhydrin. a probable mechanism for such color formation has also been proposed. measuring enrichments below the sensitivity range of conventional gc-ms. the gc-c-irms technique combines the resolution capabilities of gc with the accuracy and precision of irms. at low abundance gc-c-irms analysis it is superior in terms of time, labor, and sample requirement as compared to the conventional off-line analysis. we discuss some latest advancements and applications of gc-c-irms amino acid analysis related to nutrition research. plasma amino acids in omnivorous human subjects show a characteristic 15 n-isotopic pattern with phenylalanine and threonine showing the lowest abundance, whereas e.g. alanine and leucine are higher by 25‰ δ 15 n. in rats fed diets containing intrinsically labeled 13 c casein or the corresponding amino acid mixture labeled with 13 c leucine and 15 n lysine whole-body protein homeostasis is better supported by casein-bound than free amino acids. there is no adaptation to a low lysine diet by an enhanced bioavailability of intestinal microbial lysine to extra-splanchnic tissues in minipigs. highly selective hplc determination of tyrosine, tryptophan and their related compounds based on precolumn derivatization followed by intramolecular fluorescence resonance energy transfer detection h. nohta 1 , m. yoshitake 1 , h. yoshida 1 , t. yoshitake 2 , and m. yamaguchi 1 1 faculty of pharmaceutical sciences, fukuoka university, nanakuma, johnan-ku, fukuoka, and 2 chemical evaluation and research institute, ishii machi, hita, oita, japan we have developed highly selective hplc method for the determination of tyrosine, tryptophan and their related compounds (l-dopa, catecholamines, 5-hydroxytryptamine, etc.). the compounds were precolumn-derivatized with a commercially available fluorogenic reagent for amines by usual manner. each derivative afforded intramolecular fluorescence resonance energy transfer (fret) from the tyrosyl or tryptophoryl moiety (donor) to the labeled fluorophore (acceptor); the acceptor fluorescence was observed with the excitation of the donor at 280 nm. the derivatives were separated on a reversedphase column and then effectively detected by monitoring their fret. through the screening study of 11 fluorogenic reagents, o-phthalaldehyde (with 2-mercaptoethanol) and dansyl chloride gave the best results for the purpose. the fret detection method was highly selective and sensitive by comparison with the previous methods detecting native fluorescence of the compounds or typical fluorescence of the acceptor. the presented study was devoted to determination of the energetic effect of interactions in aqueous solutions between urea and neutral amino acid derivatives. the principal reason for studying of interactions of peptides with urea is the hope that such investigations will give insight into the factors affecting protein denaturation in aqueous solutions. the enthalpies of solution of n-acetylglycinamide, n-acetyl-l-alaninamide and n-acetyl-l-leucinamide were measured in water and in aqueous solutions of urea of molality 0.25 to 3.0 mol·kg ϫ1 using the "isoperibol" type calorimeter at 298.15 k. from the obtained standard dissolution enthalpies ∆ sol h ϱ m the enthalpic pair interaction coefficients h xy for urea-nacetylamino acid amide pairs in water were calculated. these parameters derived from mcmillan-mayer theory are regarded as a measure of effect of interactions between solute molecules in solution. the h xy values for the systems investigated suggest that the interactions between urea and amide molecules dominate the effects of dehydration of nonelectrolyte and of peptides. the replacement of the hydrogen atom in the hydrocarbon chain with a methyl group causes a positive change in the value of the enthalpic pair interaction coefficient. the obtained results were compared with those of earlier studies of interactions between electrolytes, namely sodium chloride, potassium chloride and sodium iodide and the same n-acetylamino acid amides. the effect of the solute type on the magnitude of the interaction parameter was also analysed. the side chains of amino acids in solution react in various ways with the water molecules which surround them as well as with other components of solution depending on the fact whether they possess non-polar, polar or ionic groups. many research laboratories carry out studies intended to describe precisely the intermolecular interactions with the participation of amino acid side chains. such a description may allow one to describe better the spatial structures of protein and the mechanisms of folding its surface area. the present work reports the results of calorimetric measurements of the dilution enthalpies of l-α-amino acids in water. using modified mcmillan-mayer's theory, these results served to calculate the enthalpic homogeneous interaction coefficients which characterise interactions between the amino acid zwitterions with the competitive participation of water molecules. thus, these coefficients illustrate the differences in amino acid molecules interactions both with the homogeneous amino acid molecules and water molecules around them, and consequently they may play the part of a parameter which differentiates the hydrophobic/hydrophilic properties of amino acid side chains. the enthalpic interaction coefficients of the homogeneous pairs of l-α-amino acids were compared also with the hydrophobicity parameters obtained by fauchere et al., which describe the side substituents of natural amino acids as well as aminobutiric acid (aba). based on the above statement, one may conclude that the obtained enthalpic homogeneous pair interaction coefficients of l-α-amino acids in water make it possible to systematise amino acid side chains according to their affinity to water or their hydrophobic-hydrophilic properties. thus the enthalpic homogeneous pair interaction coefficients may play the role of parameter describing the lipophilicity (hydrophobicity) of amino acid side chains. compounds (iii) with amino acid ligands. in this work we present results of x-ray investigation of fourth amino acid complexes of rhenium (iii), which have different coordination of amino acids around binuclear complexforming center -re 6ϩ . substances (glyh) 4 . 2h 2 o -in inner, but gaba has cisposition according to re -re bond. influences of fatty radical length in the amino acid ligand on week interaction between binuclear anion [re 2 cl 8 ] 2ϫ and protonized amino acid are discussed. role of hydrogen bonds in formation of crystal unit cell of investigated substances is shown. these two factors are the reason of formation of staggered conformation of an anion [re 2 cl 8 ] 2ϫ in the substance (glyh) 4 [re 2 cl 8 ]cl 2 together with existence of quadruple re -re bond that is described first. in the substance [re 2 (gaba) 2 cl 5 (h 2 o)]cl . 2h 2 o axial position of re 2 6ϩ fragment are substituted by ligands of different kind: h 2 o and cl ϫ -that says about possibilities to coordinate a substrate of biological nature exactly to these position. a precise, sensitive and reliable rp-hplc/uv method was developed to enable determination of α, and k caseins in cow's milk. the optimised method using a chrompack p-300-rp column allowed separation of caseins in 30 min. this column differs from conventional alkyl-bonded silica rp matrices in that it is an underivatised polystyrene-divinylbenzene matrix, a material which proved excellent chemical and ph stability. gradient elution was carried out at a flow rate of 1 ml/min and a temperature of 46°c, using a mixture of two solvents. solvent a 0.1% trifluoroacetic acid in water and solvent b was 95% acetonitrile-5% water-0.1% trifluoroacetic acid. the effluent was monitored by a uv detector at 280 nm. the determinations were performed in the linear range of 0.038-0.38 mg/ml for k-casein, 0.19-1.9 mg/ml for α-casein and 0.15-1.5 mg/ml for -casein. the detection limits were 0.037, 0.03 and 0.0075 mg/ml, respectively. the validity of the method was verified. the recoveries ranged from 91 to 100% for cow's milk. the precision of the method was also evaluated, the % cv being less then 3.67%. the developed methodology was also applied with success to the separation of caseins in ewe and goat milks. different chromatographic profiles were obtained for the three kinds of milk. department of aquatic biosciences, the university of tokyo, bunkyo-ku, tokyo, japan several aquatic crustaceans and bivalve molluscs accumulate a large amount of free d-alanine (3-50 µmol/g wet wt.) in their muscle tissues. during seawater acclimation from freshwater to 75% seawater, red swamp crayfish procambarus clarkii largely accumulated d-and l-alanine by 6.8-and 4.5fold, respectively, together with l-glutamine, l-proline, and glycine. the percentage of d-alanine to total alanine increased from 38% in freshwater to 48% in 75% seawater. these data indicate that d-and l-alanine are the major compatible osmolytes responsible for the intracellular isosmotic regulation of this species as well as other crustaceans. under anoxia stress for 12 h in freshwater, 50 and 75% seawater, crayfish increased d-and l-alanine in muscle and hepatopancreas in addition to the increase of lactate. the increase was much higher in seawater than in freshwater. thus, d-and l-alanine may be anaerobic end products during prolonged anoxia of this species. alanine racemase [ec 5.1.1.1] has been proved to catalyze the interconversion of d-and l-alanine in crustaceans and bivalve molluscs. this enzyme was isolated to homogeneity from the muscle of black tiger prawn penaeus monodon. the purification was 127,600-fold with 16% yield. the molecular weight of the enzyme was estimated to be 45 kda on sds-page and 90 kda on gel filtration, suggesting the dimeric nature of this enzyme. the amino acid sequences of the peptide fragments obtained from the isolated enzyme showed low homology below 50% with those of microbial enzymes. syntheses and immunological effect of thymic humoral factor-γ2 analogues research laboratory, global shinwa pharmaceutical co. ltd., yoriki, matsuomura, iwate-gun, iwate-ken, japan nine analogues of thymic humoral factor (thf)-γ2, were prepared by the solid-phase method and their in vitro restoring effect on the impaired blastogenic response of phytohemagglutinin (pha)-stimulated t-lymphocytes of uremic patients with infectious diseases were examined. the results were as follows: [arg6]-thf-γ2 exhibited higher restoring activity than that of our synthetic thf-γ2. phylos has developed a powerful combinatorial biology platform for peptide and protein selections. phylos' proprietary profusion tm technology enables the selection of peptides and proteins with desired properties. the fundamental advance represented in this unique platform is the in vitro covalent linkage of a peptide or protein (phenotype) to the encoding messenger rna (genotype). this linkage permits the selection of a protein based on its characteristics and allows the recovery and amplification of that protein through pcr, an efficient means of bring the desired proteins to easily detectable levels. profusion tm technology has routinely selected peptide and protein binders with affinity constants in the nanomolar to picomolar range. the starting library size of randomized peptide or protein profusion tm constructs is typically 10 13 . linear and constrained loop peptide libraries, for ligand generation, enzyme: substrate interaction, peptidomimetic design, and epitope mapping have been successfully used. randomized constrained loops have also been incorporated in a betasandwich scaffold, resulting in the successful selection of binders against targets of therapeutic interest. antigenic properties of three biological active de novo proteins were investigated by peptide scanning approach, using noncleavable multipin technology. a de novo protein albebetin (pid caa47376) was engineered to attain a pre-designed 3d structure and later modified by grafting short peptide fragments from human α 2 interferon (aag59605), and insulin molecules (aag59606). such protein constructs carrying important biological activities may be used in future as potential protein pharmaceuticals. despite artificial proteins are investigated for more than 10 years, immunological properties of these substances are not known. in our experiments we applied an innovative approach of raising antibodies in yolks of egg-laying hens. three continuous antigenic determinants with different immunogenic potentials have been revealed in two proteins with partially overlapping sequences. it was shown that the octapeptide interferon fragment is the immunodominant site in albeferon and albeferon-insulin molecules. on the contrary, the hexapeptides, corresponding to the insulin fragment displayed low immunogenic activity. thus we recognise that the fragments attached to the de novo frame could essentially govern immunological properties of resulting construct. no preference of any type of secondary structure was observed in antigenic determinants. nevertheless, all of them are located at the boundaries of the secondary structure elements and on the predicted surface-located sites of albebetin molecule. peptide fragments from human α 2 -interferon and insulin corresponding to the functionally important sites of their molecules were grafted into de novo protein albebetin (pid caa47376) engineered to attain a pre-designed tertiary structure with a unique topology that has not been observed in natural proteins. by means of genetic engineering the dna fragments corresponding to these peptides were inserted into the albebetin gene to obtain two variants of albebetin with antiviral fragment of human α 2 -interferon and two variants of albebetin with insulin-like peptide. the chimerical genes were expressed in escherichia coli in a fusion expression system with thioredoxin based on the plasmid pet-32 (novagen). the fusion proteins were digested by highly specific protease factor xa and the target chimerical proteins were purified and tested for their structure and biological activity. according to the cd spectroscopy study the chimerical proteins maintained the pre-designed structural properties of albebetin. toxicological testing of the proteins in the mtt-test did not reveal their cytotoxicity. antiviral activity of de novo proteins with human α 2 -interferon fragments was studied in vitro using human fibroblasts cell line l-41 and simian cell line vero. treatment of these cell lines with the proteins revealed the dose-dependent stimulated antiviral activity on fibroblasts and direct dose-dependent antiviral activity on the vero cells. one of two de novo proteins including insulin-like fragment (pid aag59607) acquired ability to stimulate glucose uptake by l-929 cells although the efficacy of stimulation was lower than that for the synthetic peptide and insulin. these results demonstrated that albebetin can be used as a scaffold for constructing of the functionally active de novo proteins possessing the pre-designed tertiary fold of albebetin and various biological activities. the identification of genes encoding unique tumor associated antigens (taas) has facilitated the development of novel immunotherapeutic strategies in cancer patients. clinical investigations have focused on targeting these cancer antigens for the generation of anti-tumor t-cell responses. taa epitopes come from differentiation antigens, from embryonal reexpressed or overexpressed proteins, from mutated proteins and from viral proteins in viraly associated tumors. we have recently developed a novel screening system for identification of immunogenic and antigenic ctl peptide epitopes using d b-/-x 2m -/double knockout mice, transgenic for a single-chain hla-a2-2m molecule (hhd mice). specific ctl were derived by immunization of hhd mice with tumor peptide extracts loaded on antigen presenting cells and with hhd transfected human tumor cell lines ctl induced against peptides from various tumors recognized tumor peptides more effectively than peptides extracted from normal tissues and also reacted with a serie of peptides derived from overexpressed candidate proteins, identified by differential display methods (sage, microarrays) comparison of ctl derived from hhd mice to ctl induced from patient's pbmc showed overlapping recognition of many candidate peptides. using these hhd mouse derived ctl we identified novel peptide sequences from prostate, bladder, breast and colon carcinomas, antigens pap and steap, from breast carcinoma antigens muc1 and ba46-1. analysis of tumor differentially expressed genes by the sage method in colon, followed by screening for hla-a2 binding peptides resulted in 500 candidate peptides for immunogenicity screening. we have identified 22 antigenic peptides of which 7 peptides were found to be immunogenic in hhd mice. interestingly 3 of these peptides are derived from the same protein. differential expression studies, using "dna chips" were performed on prostate and bladder tumors versus normal tissues. ten new candidate genes from tcc were analysed for expression and potential immunogenic peptides. novel peptides from uroplakins and from mage-8 were identified. surface plasmon resonance biosensing in the study of viral antigenic sites mimicked by synthetic peptides p. gomes 1 , e. giralt 2 , and d. andreu 2 1 centro de investigação em química da universidade do porto, portugal 2 department de química orgànica, universitat de barcelona, spain antigen-antibody binding has been regarded as one of the most representative examples of specific molecular recognition in nature. the simplistic view of antigenic recognition in terms of a lock-and-key mechanism is superseded, since it is now evident that both antigens and antibodies are flexible and can undergo substantial mutual adaptation. this flexibility is the source of complexities such as degeneracy and non-additivity in antigenic recognition. we have used surface plasmon resonance to study the effects of combining multiple amino acid replacements within the sequence of the antigenic gh loop of foot and mouth disease virus. our aim was two-fold: to explore to what extent can antigenic degeneracy be extended in this particular case, and to search for potential non-additive effects in introducing multiple amino acid replacements. combined analysis of one such multiply substituted peptide by spr, solution nmr and x-ray diffraction shows that antigenic degeneracy can be expected as long as residues directly interacting with the paratope are conserved and the peptide bioactive folding is unaltered. structural properties of creatine kinase from amphioxus, branchiostoma belcheri gray f. inoue, s. obase, t. suzuki, and t. imai department of physiological chemistry, faculty of sciences, toho university, funabashi, japan to further our knowledge of creatine kinase (ck) in the fields of molecular evolution and comparative enzymology, we analyzed the ck gene of the protochordate amphioxus. amphioxus is thought to be the phylogenetic predecessor of vertebrates and thus possesses characteristics, such as enzymological properties, that are associated with ancestral vertebrates. the results clarified the sequence of 789 bases including the active site. the homology of the active site and the surrounding 48 bases for the amphioxus ck gene to that of the human and electric ray ck-m gene was 89.6% and 87.5%, respectively. the amino acid sequence of this region of amphioxus ck was also identical to that of human and electric ray ck-m. in addition, the estimated secondary structure of amphioxus ck was compared to that of human and electric ray. there were no marked differences in the relative ratio of the α helix, sheet and turn structures for the peptide structure of ck consisting of 263 amino acid residues. there was a high degree of homology in the sequence of 25 amino acid residues (met271ϳhis295) near the active site of ck between amphioxus and other organisms, suggesting that this region of ck is functionally essential for transphosphorylation. gelsolin is a ca 2ϩ -activated and phosphoinsitide-regulated cytoskeletal actin-binding-and-severing protein, its fragments 135-142: ksglkykk (g135-142) and 150-169 khvvpnev vvqrlfqvkgrr (g150-169), are responsible for the binding of this protein to actin and the cellular messenger phosphatidylinositol 4,5-bisphosphate (pip2). the binding of peptides g135-142 and g150-169 to a cluster of four pip2 molecules in a dimyristoyl-phosphatidylcholine lipid was in vestigated by means of molecular-dynamics (md) simulations of 1,600 ps. the binding of the pip2 molecules to the peptides g135-142, g150-169 showed both electrostatic and hydrophobic nature: lysine residues of the peptides formed salt bridges with the phosphate groups of the pip2 molecules, while hydrophobic interactions occurred between the nonpolar residues of the peptides and the fatty-acid tails of pip2. during the binding some of the pip2 molecules were dragged out of the lipid, thus disrupting the bilayer. after the binding dissociated a draggen-out pip2 molecule tend to incooporate back to the lipid. division of applied physiology, institute of veterinary physiology, university of zürich, switzerland chemical modification of the proteins: bovine serum albumin, α-lactalbumin, -lactoglobulin and chicken egg white lysozyme by 3-hydroxyphthalic anhydride (3hp) yielded compounds which exerted antiviral activity in vitro as compared with the native unmodified proteins. of the three enveloped viruses tested: human herpes simplex virus 1 (hsv-1), bovine parainfluenza virus 3 (pi-3) and porcine respiratory corona virus (prcv), the 3hp proteins were shown to be active against human herpes simplex virus 1 only indicating that a perturbation of the viral envelope is unlikely. pre-incubation of vero cells with 3hp-albumin, 3hp--lactoglobulin and 3hplysozyme resulted in protection against hsv-1 infection whereas pre-incubation with 3hp-α-lactalbumin had no antiviral effect. however, all 3hp modified proteins showed a more significant inhibition when present during or after the viral infection step. thus multiple mechanisms appear to be involved in the inhibition of hsv-1 infection. the blocking of cell receptors may contribute to the antiviral activity as shown by the preincubation data. however, a direct interaction between the modified proteins and the hsv-1 glycoproteins responsible for viral entry and spread, seems to play a more important role, as indicated by the smaller ec 50 values obtained during and after the infection. a dummy or a protagonist on the stage of inflammation? r&d department, zambon group, bresso, milan, italy amino acids are usually present in large excess in healthy and the excess is used as source of calories. however, metabolic alterations are observed in ill patients and preferential retention of sulphur amino acids (saa) occurs during the inflammatory response. the metabolism of cysteine is modified during the acute phase of sepsis in rats. sulphate production is lower, whereas the higher liver production of taurine seems to play a protective role; glutathione concentration is greater in liver, kidney and other organs and cysteine incorporation into proteins was higher in spleen, lung and plasma (acute phase proteins) while albumin level decreases. another important phenomenon is the impairment of methionine conversion to cysteine during stressed condition. premature infants or hiv patients synthesise cysteine from methionine at a much lower rate. thus, the metabolic flow through the trans-sulphuration pathway may be insufficient to meet the glutathione and cysteine requirement in critical conditions. the pro-inflammatory cytokines, interleukin-1, interleukin-6 and tnf-α are the main initiates that alter protein and amino acid metabolism. in this complex picture, saa supply may contribute to the immune system regulation. our previous investigations showed some biological activity of newly synthesized cluster rhenium compoundtetrachlorodi-µ-(γ-aminobutirato)dirhenium(iii) chloride -i such as antitumour activity, cell-stabilizing activity against osmotic hemolysis, changing of morphology of cells, and other. there exists some information about stabilizing effects of some metal-organic substances with antitumour properties on the isolated ishaemic-reperfused rat heart (leperre a. 1995) throughout decrease of malonaldehyde (mda) production. some new investigations showed the influence of metal-organic substances on apoptotic processes (winter b. 1998 , syrkin a. 1998 , that are considered now as the main mechanism of such tissue damages as ishaemia, myocardial infarct, etc. thus we tried to analyze such activity of i. two models of hemolytic anemia was used: a -on rabbits by introducing of pbac 2 -solutions; this model permits to investigate dynamics of anemia in one experimental animal; bon rats by introducing of phenylhydrazine chloride. i was administrated as in solution as in lyposomic (lyp) forms. all measurements and models were accomplished according to described procedures. administration of i led to: increase of hemoglobin and resistance of erythrocytes and to prolonging of life for hemolytic animals; significant decrease in quantities of mda and increase in quantities of reduced glutathion (gsh), glutathionreductase (gsr) and glutathionperoxidase (gsp) in myocardium, blood, brain, liver, splenic and entherocites of anemic animals. the most effective was i in lyposomic form. mechanism of antioxidant action of rhenium cluster compound is speculated and experiments with some well-known antioxidants to compare with i are working out. at present problem of finding remedies against the mostly dangerous human disease -aids is one of higher interest. the aim of this work was the investigation of inhibiting effect of high-pure l-lysine-α-oxidase (lo) e.c.1.4.3.2, extracted from trichoderma sp., on hiv-virus reproduction, comparatively to azidotymidin (azt), being now in use for treatment of aids-patients. for studying of inhibiting effect of lo, the mt-4 cells, sensitive to citopathical action of virus, were used. the experimental studying has shown, that the enzyme at concentration 7-70 ng/ml suppresses hiv reproduction and synthesis of virus' proteins, not exerting toxical effect on mt-4 cells. toxical dose of lo has been determined preliminary. a comparison with standard preparation -azidotymidin, which causes suppression of virus reproduction at concentration 3 mkm (1,2 mg/ml) not exerting toxical effect on mt-4 cells. the same effect is attained having used lo in doses 7-70 ng/ml. using lower concentrations of enzyme leads to partial increasing of virus' titre comparatively to control cultures. obtained data allow to conclude that lo from trichoderma sp. is more high specific agent than azidotymidin, because it needs 1000 times lower concentration for the same action. comparison of azt and lo action on synthesis of virus' antigens presenting in cultural media of mt-4 cells infected with virus, leads to conclusion, that lo has inhibitory action both on virus' reproduction and virus' protein synthesis. department of microbiology, dokkyo university school of medicine, mibu, tochigi, japan our previous studies showed that the cellular amino acid composition obtained by amino acid analysis of whole cells, differs in various organisms. these results suggest that the difference in the cellular amino acid composition reflects biological evolution. however, the basic pattern of cellular amino acid composition is relatively constant in all organisms, and the cellular amino acid compositions of the archaeobacteria are quite similar to those determined from codon usage data, based on the complete genomes. in the present study, the free amino acid compositions in archaeobacteria, eubacteria, protozoa, blue-green alga, green alga, slime mold, plants and mammalian cells were analyzed, to investigate whether changes in their free amino acid compositions reflected biological evolution. cell homogenates were treated with 80-90% ethanol to separate cellular proteins and free amino acids contained in the cells. rat hepatoma cells (r-y121b) were cultured in eagle's minimum essential medium (mem) containing 5% serum or in a modified mem lacking arginine, tyrosine and glutamine. no significant difference in the free amino acid composition was observed between the two cell groups cultured under two different conditions. the patterns of the free amino acid compositions differed completely from those of the cellular amino acid compositions, and from each other in various organisms. characteristic differences were observed between plant and mammalian cells, and between archaeobacteria and eubacteria. the patterns of the free amino acid composition in blue-green alga, green alga, protozoa and slime mold differed from each other and from those of eubacteria and archaea cells. it has been suggested that the free amino acid composition reflects apparent biological changes as the result of evolution. 2) catalyzes the hydrolysis of gamma-glutamyl compounds such as glutathione, and the transfer of their gamma-glutamyl moieties to amino acids and peptides. we previously developed enzymatic methods for the synthesis of various gammaglutamylamino acids using the transfer reaction of ggt from e. coli k-12 as a catalyst. it has been reported that gamma-lglutamyltaurine has a potent and long-lasting antiepileptic action, and its chemical synthesis has also been reported, but it required protecting and deblocking of reactive groups. thus, the purpose of this study was to develop an enzymatic method for the synthesis of gamma-l-glutamyltaurine using ggt. the optimum reaction condition was 200 mm l-glutamine, 200 mm taurine and 0.2 unit/ml ggt, ph 10, and 1-hr incubation of 37°c. forty-three mm gamma-glutamyltaurine was obtained and the yield was 21.%. gamma-glutamyltaurine was purified by dowex 1 ϫ 8 column and c18 column, and then identified with gamma-l-glutamyltaurine by nmr and polarimeter. in this study the yield of gamma-l-glutamyltaurine was comparatively low because synthesized gamma-lglutamyltaurine was promptly converted into the by-product, gamma-l-glutamyl-gamma-l-glutamyltaurine. the production of antimicrobial peptides is an important aspect of host defense in animals ranging from insects to mammals. they do not target specific molecular receptors on the microbial surface, but rather assume amphipathic structures that allow them to interact directly with microbial membranes, which they can rapidly permeabilize. they are thus perceived to be one promising solution to the growing problem of microbial resistance to conventional antibiotics. insects express a battery of potent antimicrobial proteins in response to injury and infec-tion. until now, approximately 170 immune peptides have been characterized from insects and other invertebrates. an antimicrobial gene (md-cecropin) belonging to cecropin family was cloned from the bacteria-charged adult house fly, musca domestica. expressed in the vector pgex-4t1. mrna was isolated and degenerated primers were designed according to the conserved sequences of cecropins. the full-length cdna encoding md-cecropin was cloned by rt-pcr and 5ј, 3ј-race and sequenced. the deduced amino acid sequence indicated that a prepeptide with 63 amino acid residues is first translated and then processed to a mature peptide with 40 amino acids. the dna encoding the mature peptide was subcloned into expression vector pgex-4t1, and expressed efficiently in e. coli bl21 as a fusion protein. the fusion protein was purified and specifically digested and the md-cecropin was further purified to homogeneity and the activity spectrum was investigated. escherichia coli with metabolic engineering methods l. yun, x. zhang, s. wang, q. xu, and l. ma biotechnology laboratory, institute of beijing radiation medicine, beijing, p.r. china a bioengineering escherichia coli strain was obtained by metabolic engineering method. three genes related to the biosynthesis of phenylalanine, arog, phea, and tyrb encoded key enzymes: 3-deoxy-d-arabino-heptulonate-7-phosphate synthetase (ds), a bifunctional protein-chorismate mutase (cm)/prephenate dehydratase (pd) and aminotransferase (at), respectively. in this work, the feedback inhibition of ds and cm/pd were relieved by site-directed mutagenesis on bases of homology comparison of related sequences of the key enzyme. the feedback inhibition resistant genes encoding ratelimiting enzymes in the main and terminal pathways were amplified by co-expressed in order of arog-phea-tyrb on the plasmid by their own operator plpr, pl, and pr. in the recombinant strain showed great resistant to the l-phenylalanine analogues, the specific activities of ds, cm, pd and at were increased by 3.10, 3.29, 4.91 and 8.16 folds, respectively. as the result, the amount of phenyalalnine biosynthesis of the bioengineered strain was increased greatly compared with that of the host strain. an enzymatic approach for the mapping of phosphoproteins resolved on two-dimensional polyacrylamide gels hiroshima proteome laboratory, regional science promoter program, kagamiyama higashihiroshima, japan an enzymatic approach for high-throughput mapping of phosphorylated proteins resolved on two-dimensional (2-d) polyacrylamide gels is presented. proteins of cultured rat skin fibroblasts were divided into two aliquots, one of which was dephosphorylated using recombinant 1 protein phosphatase. the two aliquots were then subjected to 2-d electrophoresis. the phosphoproteins could be mapped on the 2-d gel by com-paring the gels of the phosphatase-and non-treated samples, because the dephosphorylated proteins shifted to more basic positions on the gel. this technique revealed that approximately 5% of the detectable proteins were phosphorylated. fifteen phosphoproteins were identified by mass spectrometry, including proteasome component c8 and small glutamine-rich tetratricopeptide repeat-containing protein. furthermore, the extent of phosphorylation of two actin-modulating proteins, destrin and cofilin, was found to be significantly reduced when the cells were chemically or enzymatically detached from the culture dishes. the presented technique can be applied to all biological materials because it requires no protein-labeling step, and is therefore useful for high-throughput mapping of phosphoproteins in proteome research. with the completion of the human genome sequence maldi-tof-ms is increasingly becoming an established method for identification of proteins separated by 2d gel electrophoresis. mono-isotopic peptide mass fingerprinting (pmf) has been previously shown to be amenable to full automation encompassing the process of acquisition, data processing and databank searching under full software control. until now the throughput of maldi-tof-ms for proteomics has been limited to several hundred samples in a working day and this represents approximately 5-10% of the total proteins resolved by a large format 2d gel. to reduce the number of proteins to be identified the 2d gels are imaged and analysed to determine differences in expression levels within a set of gels. although much of the image processing is semiautomated the comparison is labour intensive as manual pattern matching has a role in the gel alignments (land marking). increased ms sample throughput allows the possibility of identifying every protein spot in a 2d gel within a day. this could eliminate the potentially erroneous step of human gel image alignment, whereby land marking could be achieved using the ms data. increased sample throughput requires greater capacity and robust unattended instrument operation. in this poster we describe an integrated robotic multiple plate loader that allows overnight unattended ms operation. other improvements include an increased laser repetition rate that allows the data capture rate to increase four fold. sample tracking, data archiving and data reporting are essential attributes of this new technology and these aspects are outlined in the presentation. the proteinchip tm biology system for ciphergen biosystems: a novel proteomics platform for rapid biomarker discovery, validation and identification ciphergen biosystems ltd., surrey technology centre, the surrey research park, guildford, surrey, u.k. the proteinchip system uses seldi (surface enhanced laser desorption/ionization) proteinchip technology to perform the separation, mass detection and analysis of proteins at the femtomole level directly from biological samples. surfaces are based on either chromatographic based chemistry (ion exchange, reverse phase, imac etc.) that bind large classes of proteins or biologically defined surfaces (antibodies, dna, receptors, etc.) that are used to investigate specific proteininteraction events. as with conventional elution chromatography each type of surface is designed to bind a different subset of proteins from a crude mixture. sample complexity is reduced on the surface by washing with standard biological buffers compatible with the chosen proteinchip array. unlike elution chromatography, proteins are detected directly from the stationary phase using laser based mass spectrometry greatly increasing throughput whilst reducing sample loss and improving reproducibility. multiple proteinchip surface and wash conditions are explored with a small sample set to resolve hundreds of proteins and establish assay conditions that reveal candidate biomarkers or diagnostic protein profiles. the resulting custom built assay is then used to monitor disease processes or drug toxicity profiles by screening large banks of samples such as tissue extracts or physiological fluids (serum, urine, csf, etc.). pharmaceutical research, genomics technologies, f. hoffmann-la roche ltd., basel, switzerland to the present, samples representing the total protein mixture have been usually analyzed by proteomics technologies mainly only the abundant, hydrophilic components have been visualized. these proteins could be solubilized with reagents compatible with isoelectric focusing, for example urea and chaps. such an analysis provides us with a limited image of the proteome, which is insufficient for the detection of the majority of the proteins. in a 2-d gel, where about 1 mg of protein amount has been resolved, 1,000-3,000 protein spots can be detected, using coomassie blue staining. the spots represent the products of only 200-300 different genes. other gene products, not visualized, are most likely expressed at too low levels for detection or they can not be identified because of limitations of the current technology, they are too small, too large, basic or hydrophobic. here we will discuss protein enrichment approaches prior to the analysis, which we have applied for the enrichment of bacterial and eukaryotic proteins. proteomic analysis of the rat liver mitochondrial proteins m. fountoulakis 1 , j.-f. juranville 1 , and l. suter 2 1 genomics technologies, and 2 drug safety, f. hoffmann-la roche ltd., pharmaceutical research, basel, switzerland subcellular fractionation increases the probability of detection of low-abundance proteins. we prepared mitochondrial, microsomal and cytosolic protein fractions from total liver of male rats. the proteins of the three fractions were analyzed by two-dimensional electrophoresis using broad and narrow ph range immobilized ph gradient strips. the proteins were identified by martix-assisted laser desorption ionization mass spectrometry. in the mitochondrial fraction, 190 different gene products were detected. approximately 70% of the identified mitochondrial proteins are enzymes with a broad spectrum of catalytic activities. most of the identified proteins had been detected before in other samples as well, analyzed in our laboratory. eight gene products were detected for the first time. these were represented by one spot each, whereas most of the frequently detected proteins were represented by multiple spots. in average, approximately 15 spots corresponded to one gene product. centre for molecular medicine, university college london, u.k. three kinds of experiments have been carried out successfully in our labs. (1) identification of post-translational modifications of the endothelin a and b receptors (etar and etbr) including both phosphorylation and acylation. we have developed new, very efficient methods for single step isolation of highly pure etar and etbr from cells. this has allowed us to obtain evidence that the post-translational modifications are very complex and result in multiple phenotypes showing different forms of modification for receptor. as with other systems, e.g. insulin-like growth factors, it is probable that these multiple phenotypes of the et receptors correspond to different forms of signalling dependent on cellular state, e.g. the cell cycle. it is, for example, already clear from the phosphorylation of the receptor that a series of different kinases must be involved. (2) following stimulation of fibroblasts with endothelin, phosphorylation/dephosphorylation signalling cascades involving several hundred proteins have been observed by use of high resolution 2d electrophoresis and detection of phosphorylated proteins labeled with 32 p by autoradiography or immunological methods. the large number of proteins involved are being identified by mass spectrometric methods such as mass fingerprinting or sequencing by mass spectropmetry. (3) differential gene expression has been followed by using 35 s met pulse chase labelling concurrently with endothelin stimulation. at least 50 proteins showed significant changes in expression of 2d gels and these proteins are also being identified. these experiments demonstrate that it is now possible to use proteomics methods to investigate the integration of response to an extracellular signal at the levels of the receptor itself, the subsequent signalling cascades and the ensuing gene expression. the proteomics technology permits concurrent monitoring of large numbers of protein phenotypes (the forms and amounts of individual proteins and is therefore able to provide a global overview of signalling processes which greatly augments more traditional investigations of individual proteins or pathways. furthermore, these new methods will allow quantitative determination of the changes in protein phenotypes, which is very important in view of the highly non-linear amplification properties of such signalling processes. an integrated approach to automated high throughput protein identification by 2d gel electrophoresis and mass spectrometry d. gostick 1 , s. cohen 2 , p. young 1 , b. karol 2 , j. langridge 1 , j. randell 3 , t. slyker 3 , and a. jacobson 3 1 micromass, manchester, u.k. 2 waters corporation, milford, massachusetts, and 3 bio-rad laboratories, hercules, california, u.s.a. establishing the function of gene products is the major challenge of the post genomic era. the rate-limiting step in this endeavour is the speed with which proteins can be isolated and identified. separation of proteins from cell lysates or sub-cellular domains by 2d gel electrophoresis is an established method of visualising these complex systems. recently mass spectrometry has proved to be a powerful method of further characterising these proteins. from the mass spectrum of the enzyme digest of a 2d gel spot, the resulting digest map is compared with the theoretical maps from the databases and the protein identified when these correlate. maldi-tof is of great benefit in these studies since it requires a minimal amount of sample, is relatively tolerant to salts and other contaminants arising from the gel and may be configured for automated sample analysis. high sample throughput with automated analyses including data processing and client-server database searching are already available. our system automatically acquires the data and processes the maldi mass spectrum into a monoisotopic peak list. this peak list is then automatically sent to a networked database for protein identification. when proteins are not identified from the maldi analysis or an ambiguous result is obtained, then further analysis of the sample by electrospray caplc-ms-ms is required. the development of a hybrid quadrupole orthogonal acceleration timeof-flight mass spectrometer (micromass, q-tof) has facilitated the generation of unambiguous amino acid sequences from the ms-ms analyses of tryptic peptides. these ms-ms spectra can be automatically searched against protein, nucleotide or est databases. thus enabling protein identification from gel spots, despite non-specific enzymatic cleavage, protein co-migration and post transitional modifications. for organisms who's genome sequences are poorly represented in the data bases de novo amino acid sequencing may be required. inferring de novo peptide sequences from ms-ms data is complex and is often the rate-determining step in this method. however, it is now possible to interpret the ms-ms spectrum automatically. in our approach the raw ms-ms spectrum is reduced to the plausible single-charge, monoisotopic mass spectrum. sequence interpretation is achieved by generating "trial sequences" consistent with the experimentally determined molecular weight. a probabilistic fragmentation model is used to transform the trial sequences to predicted spectra for comparison to the single-charge, monoisotopic spectrum and to calculate the likelihood that the trial sequence would account for the observed data. the possible number of trial sequences for any peptide is large, for example there are 20 10 possible sequences for a peptide containing any of the 20 naturally occurring amino acids and having 10 residues. to reduce the scale of the problem a terminated markov chain monte carlo algorithm is used to produce sequences. this bayesian method simulates an exhaustive search of all sequences having the correct mass. the huge increase in genomic sequence information available, combined with the increased sensitivity and selectivity provided by mass spectrometry, has allowed large-scale protein identification. however the analysis of the post translational modifications present on the identified proteins is a more challenging problem. currently the approach that offers the most expedient and specific solution, to determine modified peptides, is precursor ion scanning. this approach has primarily been performed on a triple quadrupole mass spectrometer where the rear quadrupole, (ms2) is set to transmit only the fragment ion of interest. the ms1 quadrupole is then scanned across the appropriate mass to charge range. in this paper we describe a method that allows specific post translationally modified peptides to be identified and sequenced during the course of an hplc experiment on the q-tof mass spectrometer. during the hplc run the instrument is switched alternately at one-second intervals between low and high collision energy with argon in the collision cell. the quadrupole, ms1 is not mass selective, operating in the rf only mode. the first data set at low energy (4ev) shows only the normal pseudo molecular ions. the second at higher energy shows their fragments. wherever a product ion of interest occurs in the high-energy data all its possible precursors are revealed by the corresponding 4ev data. since the two data sets contain the entire set of precursor and product ions that can be formed it is clearly possible to generate the equivalent of a constant neutral loss scan. this is invaluable in the case of phosphorylated peptides where the neutral loss of 98da (h 3 po 4 ) occurs via -elimination from the phosphoserine and phosphothreonine residues. this allows the q-tof mass spectrometer to switch from the ms mode to the ms/ms mode of operation when a potential pseudo molecular ion exhibits a neutral loss of 98 da between the high energy and low energy data sets. the product ion ms/ ms spectrum can then be acquired on the phosphorylated precursor ion. in the case of phosphotyrosine, neutral loss of the h 3 po 4 moiety is not observed, however a low mass immonium ion at m/z 216 can be detected. this characteristic ion (from the high energy data) is used to direct the mass spectrometer to fragment potential phosphopeptide precursor ions, which are selected from the low energy data. in this case several precursor ions may require ms/ms interrogation at one decision making time-point. with the first draft of the human genome completed largescale protein identification by mass spectrometry, even for samples originating from higher organisms has become relatively straightforward. this requires a high throughput facility to identify proteins that have usually been separated by 2d page. the approach providing the highest level of automated sample throughput, in terms of samples per hour, is currently maldi-tof-ms. this technique provides a peptide mass fingerprint of the protein digests and allows the rapid and accurate identification of the parent protein by comparison to a databank. however, under some circumstances, for example if the number of peptides detected is small or if the sequence coverage is poor, it is advantageous to be able to include even a short piece of sequence information to provide added specificity. in a conventional maldi-tof-ms instrument post source decay (psd) can be used to try and generate sequence information, however this approach is notoriously unreliable in producing good quality ms/ms data. one reason for this is that the peptide ions do not undergo fragmentation in a controlled environment such as a gas cell with selected collision gas and collision energy. an alternative approach is to use the predictable fragmentation obtained from a hybrid quadrupole ortho maldi source has been fitted to a hybrid quadrupole orthogonal acceleration time-of-flight (q-tof) mass spectrometer. in contrast to a conventional maldi-tof-ms instrument the resolution and mass measurement accuracy of the data is comparable between the ms and ms/ms modes. this allows superior data acquisition in the ms-ms mode compared to conventional maldi-tof-ms. a number of modifications have been made to optimise the system for high throughput proteomics. the maldi source has been configured with a high-density target plate, compatible with a 96 well microtiter plate. the acquisition software has been modified for automated data acquisition in both the ms mode and the ms to ms/ms switching mode. dedicated processing software has been developed to fully automate the post acquisition and databank searching. this software has been optimised to consider the unique nature of the data acquired from this configuration of instrument. in this paper we demonstrate the how an maldi-q-tof instrument can be used for high throughput proteomics. we also compare and contrast is functionality in comparison with alternative strategies for high throughput proteomics, namely conventional maldi-tof-ms and electrospray lc-ms/ms. pseudomonas putida is an ubiquitous, metabolically and physiologically extremely variable soil bacterium. it is kown to be a good colonizer of plant roots and a plant growth promoter. now, after the sequencing of the total genomic dna has been finished we have focused on the functional analysis of this strain. plant growth promotion is achieved in different ways. one is the inhibition of fungal and bacterial phytopathogens, which is known to be a multifactorial mechanism. an important factor of this mechanism is the production of siderophores (iron-transport-agents), small linear or cyclic peptides, which are synthesized in a ribosomal-independent manner by special synthetases. the siderophore production is induced by iron limitation. the regulation of this process was investigated by pulselabelling with [ 33 p] inorganic phosphate. 2d-protein patterns generated from cells grown with and without fesupplementation were compared. proteins which were phosphorylated under iron limitating conditions were analysed by maldi-tof peptide mass fingerprint. for the identification of the proteins we used an in-house peptide mass database which has been built based on the genomic sequence data. bio-rad laboratories, inc., hercules, california, u.s.a. worksbase software for proteomics is a platform independent information management system encompassing laboratory experimental workflow and bioinformatics for protein and biochemical research. the worksbase system is designed to allow direct internal integration between laboratory experimental data and background biological knowledge found in reference and in-house data, such as gene, protein and functional annotation databases. worksbase provides a crossdisciplinary research infrastructure for drawing together multiple lines of evidence for characterization of proteins, and integration of this data with domains such as gene expression, pharmacological screening, structure and related areas. while the focus is on the biology underpinning the experimental work, the system is also designed with the capability of providing a sample and workflow tracking system for use in the wet lab, effectively a proteome lims (laboratory information management system). as experimentation proceeds in the laboratory, worksbase software can be used for development of hypotheses on protein, biochemical pathway, and post-translational processing involvement in biological systems and disease processes. as such, identifications that are derived from lab work and user observation can be used to augment the reference data repository. however, unlike databases ands systems where the methods and reasoning for assignment of annotations are obscure, by maintaining the link between the source data and the biological roles derived from them, the accuracy and integrity of any information stored in the worksbase system can be directly ascertained. changes in the brain protein levels following administration of kainic acid k. krapfenbauer 1,3 , m. berger 2 , g. lubec 3 , and m. fountoulakis 1 1 f. hoffmann-la roche ltd., pharmaceutical research, genomics technologies, basel, switzerland 2 institute of cancer research, and 3 department of pediatrics, university of vienna, austria kainic acid (ka), a potent neurotoxin and excitatory amino acid, leads to derangements and modulation of brain proteins. no global brain protein expression pattern induced by ka-treatment has been reported yet. we studied the effect of systemic ka administration on the levels of brain proteins. rats were injected placebo or ka intraperitoneally and brain was taken after one week. the mitochondrial and cytosolic fractions of the brain proteins were analyzed by proteomics technologies. heat shock protein hsp 27 was exclusively detected in brains of animals treated with ka. the levels of neurofilaments and alpha-internexin were significantly decreased and a fragment of tubulin alpha-1 chain was manifold increased in ka-brains. the mitochondrial enzymes dihydrolipoamide dehydrogenase, atp synthase beta chain and isocitrate dehydrogenase were reduced and pyruvate kinase m1 was increased following ka treatment. the results indicate altered regulation of heat shock proteins, neuronal death, cytoskeletal disruption and mitochondrial derangement by systemic ka administration. this report confirms and extends previous studies on the effect of ka on the expression of brain proteins and suggests that our analytical system can serve as a model for neurotoxicological, neurobiological and neuropathological proteome studies. the rat brain mitochondrial proteins genomics technologies, f. hoffmann-la roche ltd., pharmaceutical research, basel, switzerland we constructed a two-dimensional database for rat brain mitochondrial proteins. rat is a useful model of human diseases of the central nervous system. in order to detect alterations in the levels of the low abundance brain proteins, the mitochondrial, microsomal and cytosolic fractions were prepared. the proteins of each fraction were analyzed by two-dimensional electrophoresis, followed by martix-assisted laser desorption ionization mass spectrometry. approximately 500 proteins were identified in the mitochondrial fraction, which were the products of 165 different genes. about 75% of the identified proteins were detected in the mitochondrial fraction only and the rest were detected in the cytosolic and about 2% were found in the microsomal fraction as well. 98 of the 165 proteins had not been detected before in our laboratory. the identified proteins were in the majority enzymes or enzyme subunits with a broad spectrum of catalytic activities and heat shock proteins. whilst lc-ms/ms has been utilised for the identification of proteins from complexes and cell lysates (qualitative proteomics), the quantitative study of gene expression using differential display has until recently been the preserve of a 2d gel based proteomic experiment. however, recently a great deal of interest has been generated on the use of isotope coded affinity tags (icat) for the quantitative study of gene expression at the proteome level. the technique is based upon chemically modifying the cysteine residues of proteins isolated from cells in two different states with light and heavy isotopically labeled reagents. the two cell states are then combined, digested with trypsin and the cysteine containing peptides preferentially selected by binding to an avidin column, prior to analysis by mass spectrometry. the eluent from this column is then analysed by capillary lc esi-ms/ms. interrogation of the eluting peptides by tandem mass spectrometry and databank searching results in the identification of the associated protein. we describe how icat data analysis has been automated within a software environment. the ms and msms data acquired using the qtof instrument are processed and analysed using a new algorithm which recognises related isotope clusters and quantifies their relative intensities. based on a user defined ratio threshold the software will automatically carry out an lc-ms/ms experiment and databank search in a client-server mode and provide a report of the identified proteins and their expression ratio in the two cell states. deterioration of the transcriptional, splicing and elongation machinery in brain of fetal down syndrome b. lubec 1 and m. fountoulakis 2 1 department of neonatology, university of vienna, austria 2 gene technologies, cns research, f. hoffmann la roche, basle, switzerland perturbation of brain development i.e. regulation of gene expression, differentiation, growth and migration in down syndrom (ds) has been reported to occur early in life pointing to impairment of the complex system of transcription and or translation and indeed, altered expression of transcription factors has been reported in adult ds brain. we therefore decided to compare the transcriptional and translational machinery in cortex of brains of controls and fetuses with down syndrome in the second trimenon of gestation. we determined a series of transcription/translation factors by 2 d-electrophoresis followed by maldi -identification and quantification with specific software. the protooncogene c-crk, crk-like protein, elongation factor 1-alpha 1, elongation factor 2, elongation factor tu and two out of four spots representing ptb-associated splicing factor psf were significantly downregulated in brain of fetal ds fetuses as compared to controls. the finding of reduced transcription and translation factors may indicate deranged protein synthesis. the underlying cause for individual reduced transcription, splicing and translation factors may be explained by chromosomal imbalance or by posttranslational modifications as e.g. phosphorylation, known to be aberrant in ds. reduced expression of transcription factors in fetal ds during early life may be responsible or reflecting impaired brain development and deficient wiring of the brain in ds. r. mazzoli 1 , m. g. giuffrida 2 , e. pessione 1 , g. dellavalle 2 , c. barello 2 , e. griva 1 , and c. giunta 1 1 dipartimento di biologia animale e dell'uomo, università di torino, and 2 csaapz-cnr. c/o bioindustry park canavese colleretto giacosa (to), italy a fast phenol degrading acinetobacter radioresistens strain was isolated in our laboratories and selected for bioremediation applications. this bacterium is also able to grow on benzoate and catechol as sole carbon-energy sources, metabolizing them via the ortho route. in previous researches we detected, by means of proteome analysis, some marker enzymes of the phenol and benzoate degradative pathways. in the present work we extend the identification of the proteins involved in the aromatic-ring opening (the different components of the phenol hydroxylase and benzoate dioxygenase, the catechol dioxygenase isozymes) together with other satellite proteins specifically induced by the aromatic growth substrate. of these last proteins some are probably related to the cellular uptake of benzoate and phenol while others are ascribed to the groel family of heat-shock chaperonines, involved in proteins processing and folding. aromatic substrates may thus act as stress-agents like heat or cold. proteomic studies on rat body fluids i. miller 1 , r. wait 2 , l. sironi 3 , i. eberini 3 , m. gemeiner 1 , e. tremoli 3 , and e. gianazza 3 1 veterinärmedizinische universität, wien, austria 2 imperial college school of medicine, hammersmith, london, u.k. 3 universita' degli studi, milano, italy previously, we have characterized rat serum proteins, both under "normal conditions" and during experimental inflammation, using two-dimensional electrophoretic separation, densitometric quantitation and identification by mass spectrometry and immunological procedures (http://linux.farma.unimi.it/ homeframed.html). we have now extended these studies to the protein composition of cerebrospinal fluid (csf) and urine, and have identified several proteins specific to these fluids, including major urinary protein, uromodulin, and prostaglandin d synthase. these baseline data provide a useful comparison to the biological fluids of stroke-prone spontaneously hypertensive rats, an inbred strain, which develops cerebrovascular abnormalities following high blood pressure. our studies have detected signs of an inflammatory condition several weeks prior to stroke. we have confirmed the sharp rise in proteinuria preceding stoke onset, and have identified the excreted proteins. following stroke we observe a massive increase in csf protein concentration as serum proteins, even those of large molecular size, cross an impaired blood-brain barrier. as a first step to discover useful disease markers from the urinary proteome, we have developed a unique and systematic approach for detection of low molecular weight urinary proteins by using high resolution two-dimensional (2d) electrophoresis and mass spectrometric methods. unlike previous studies on urinary proteins, and most importantly as observed in present study, our results show that a large number of low molecular weight protein spots can be visualized in the 2d electrophoresis pattern. it was observed that protein concentration and fractionation methods were critical for our ability to detect many proteins in the gel pattern. therefore, several approaches were carefully considered to concentrate and fractionate proteins in urine samples. initially, urine specimens from normal individuals were concentrated by using centrifugation and ultrafiltration methods. the concentrated samples of urine proteins were then fractionated by size exclusion and immunoaffinity chromatography. the size exclusion method was used to generate two fractions of proteins based on their native molecular weights. further, this method allowed us to enrich concentrations of less abundant proteins for each fraction. the immunoaffinity method was used to specifically remove well-known abundant urinary proteins (such as albumin) from the above mentioned two fractions. that the 2d pattern includes many native low molecular weight proteins was confirmed by analyzing both protein fractions from size exclusion chromatography. a detailed mass spectrometric analysis of the protein spots is carried out to identify the proteins observed in 2d pattern. since urine is an ultrafiltrate of plasma, many factors in urine are present in proportion to their rate of synthesis in the body. these factors include many low molecular weight proteins that remain undiscovered due to their low abundance. therefore, the present analysis of urinary proteins would serve as the most useful guide for the discovery of novel diagnostic markers in urinary proteins. i. pucci minafra 1,2 , s. fontana 2 , p. cancemi 1 , g. alaimo 1 , and s. minafra 1,3 1 centre of experimental oncobiology, 2 department of cell biology and development, and 3 institute of histology and embryology university of palermo, italy breast cancer is one of the leading causes of death for cancer among women. there are different types of breast cancers, grouped as invasive and non-invasive types. among the invasive types "infiltrating ductal carcinoma" (idc) accounts for about 80% of all breast cancers. in order to study some biological properties related to this type of cancer, we have developed and well characterized an "in vitro" system, consisting of an idc-derived cell line, 8701-bc (minafra et al., br. j. cancer, 60, 185-192, 1989 ) and some of its cloned cell lines, selected for their high and low invasive activity in matrigel. using this model we are producing proteomic maps to compare with that of non-tumoral breast epithelial cells and with breast tissue fragments, existing in our collection or available at the expasy proteomics server. protein identification is currently done by means of gel matching, edman-microsequencing and immuno-detection. to rationalize data we grouped proteins into functional categories: a) cytoskeletal proteins, b) metabolic enzymes, c) chaperonins and other functionally related proteins, d) peptides and enzymes with regulatory functions. a fifth group consists of peptides with unknown identity. among these sets of proteins we found that glycolitic enzymes and some chaperonins are overexpressed in cancer cells. in addition, new isoforms of potential interest as biomarkers for breast cancer, were identified by means of microsequencing. a. santucci 1 , l. trabalzini 1 , d. soldateschi 2 , e. ferro 1 , a. paffetti 1 , and p. martelli 1 1 dipartimento di biologia molecolare, sezione di chimica biologica, universita' degli studi di siena, and 2 diesse diagnostica senese srl, siena, italy human cytomegalovirus (hcmv) is an ubiquitous virus, belonging to the herpesviridae family, betaherpesvirinae subfamily, able to induce morbidity in immunocompromised patients and congenitally infected new-borns. hcmv has the largest genome among the herpes-viruses (240 kbp): ad169 strain genome was completely sequenced, containing about 200 open reading frames encoding polypeptides, most of which are not characterized. the viral genes are activated in a cascade fashion: 1) alpha, immediate-early genes, coding for regulatory proteins necessary for the activation of 2) beta, early genes, needed for dna replication, and, finally 3) gamma, late genes, coding for structural proteins of the mature virions. this latter category includes the virus surface antigenic proteins responsible for the main immune response during hcmv infections. although the sequencing of hcmv genome has been completed, very little is known about the actual nature of the viral proteins. the most appropriate approach to characterize hcmv phenotype is to study its protein expression as it is carried out within the host cell. for this purpose, we analyzed by two-dimensional electrophoresis (2d-page) the protein phenotipic repertoire of human fibroblasts and compared it with that of the same cell type following infection with hcmv strain ad169. the phenotypic 2d map of human fibroblasts dramatically changes following infection with hcmv. a relevant amount of newly appeared spots is attributable to hcmv proteins, mainly of the structural category, since we analyzed host cells at the 7-9th day of infection, when the late, gamma genes are supposed to be the only to be activated. on the other hand, a marked decrease of protein synthesis can be easily evidentiated in the infected fibroblasts respecting to uninfected cells. a temptative mapping of the main structural viral proteins (those against which patients sera are directed) was carried out by immunoblotting, microsequencing and mass spectrometry. comparative proteomics of cultured cells: identification of genetic defects and molecular mechanism of apoptosis regulation v. seyrantepe 1 , k. landry 1 , s. taurin 2 , s. n. orlov 2 , and a. v. pshezhetsky 1 1 sainte-justine hospital research centre, and 2 research centre, chum, university of montreal, montreal, pq, canada we employed a comparative proteomics of cultured cells to study mechanism of genetic disorders and for identification of key proteins involved in cell proliferation, differentiation, and death. in particular, this technology proved to be very useful to understand molecular basis of severe inherited diseases resulting from deficiency of lysosomal membrane transporters, and a role of programmed cell death (pcd) of vascular smooth muscle cells (vsmc) in cardiovascular disorders. to increase sensitivity of the identification of cellular proteins we have either have isolated cellular organelles such as lysosomal membranes or performed the differential extraction of soluble, membrane and cytoskeletal proteins. by comparison of pro-teomic cell maps from normal controls and individuals affected with lysosomal transport disorders we have selected and identified several candidate disease-causing proteins, which have to be further studied by mutation analysis and functional expression. for the second group of disorders we identified proteins, which de-novo synthesis could result in survival of vsmc including a two members of hsp70 family, a molecular chaperone grp78, and so-called mortalin (grp75) highly expressed in non proliferative tissues and associated with mortal cell phenotype. two-dimensional polyacrylamide gel electrophoresis (2d-page) is the established technology employed for the separation of proteins from a cell lysate, sub-cellular organelle or tissue sample prior to identification of the excised protein spots by mass spectrometry. in the order of several hundred to several thousand proteins, can be separated and visualised on a 2d gel by conventional staining or utilising fluorescent labelling techniques. the advantage of performing a two dimensional gel based separation is the ability to obtain quantitative information by comparing and contrasting two samples in a differential display experiment, for example, between a healthy and diseased state. the last stage however stipulates that the gels are reproducible which can be both difficult and time consuming to achieve. the relativity poor dynamic range that the gels exhibit also limits quantification. other restrictions include the under representation of certain classes of proteins, such as membrane proteins, large or small proteins and very acidic/basic proteins. for these reasons, amongst others, alternatives to 2d-page are being investigated. advances in both lc and mass spectrometry instrumentation have allowed the analysis of protein complexes, which have not been separated on a 2d gel. in this case protein identification is achieved via database searching of esi-ms/ms data. this provides qualitative information on the proteins that are present and has recently been coupled with isotope dilution experiments to provide relative quantiative information. these experiments normally involve separation of the complex digest mixture by microcapillary liquid chromatography connected to an instrument capable of data dependant switching between the ms and ms/ms modes. using this approach it has been demonstrated that hundreds of ms/ms spectra can be acquired in a fully automated fashion, resulting in the identification of significant numbers of proteins, including low copy number proteins, from a single lc-ms/ms experiment. if, however, a complex protein mixture is to be investigated then a fractionation step prior to separation of the peptides on the basis of their hydrophobicity would be advantageous. we have, therefore, adopted a 2d lc-ms/ms approach using a capillary lc system (caplc) operating at nanoliter per min flow rates coupled to a q-tof 2 mass spectrometer. by replacing the standard sample loop within this system with a strong cation exchange (scx) cartridge followed by a c18 trap cartridge it is possible to pre-fractionate the peptides before separation on a c18 column. after loading the sample, discreet fractions are sequentially eluted from the cation exchange cartridge using a salt step gradient; the eluted peptides are then retained on the trapping c18 cartridge whilst they are desalted. finally the peptides are eluted from the c18 pre-column, at 200 nl/min, onto a 75 um id ϫ 10 cm waters symmetry analytical column for separation and elution into the mass spectrometer. this analytical approach will be discussed with examples where this methodology has been used for the analysis of standard protein mixtures and also for the analysis of cell lysates and sub-cellular fractions. monoclonal igg are commonly observed in various b cell disorders, the most clinically relevant being multiple myeloma. in a series of 73 serum samples, immunofixation identified igg 1 , igg 2 , igg 3 , and igg 4 in 63, 4, 5, and 1 cases, respectively. their light-chains were k in 45 cases and λ in 28 cases. these monoclonal igg were further characterized by high resolution two-dimensional polyacrylamide gel electrophoresis (2-de) with various isoelectric focusing conditions as well as by 3-de (2-de of the proteins extracted from agarose after serum protein agarose electrophoresis). after 2-de or 3-de, the monoclonal γ-chains were not visualized in 29 out 73 cases, whatever the isoelectric focusing conditions that were tested. in 6 cases, γ-chains were only detected using alkaline ph 6-11 gradients. monoclonal γ-chains and light chains were highly heterogeneous in terms of pi and mr. however, a good correlation (p ͻ 0.05) was observed between the index of migration of the monoclonal igg in agarose gels and the pi of their γand of their light-chains (r ϭ 0.735, multiple linear regression). because of the extreme diversity of the different γ-chains as well as of the k-and γ-chains, it appears that a classification of monoclonal igg based only on their electrophoretic properties is not possible. alzheimer's disease (ad) is one of disorders caused by protein conformational changes and recent studies have shown that several chaperone proteins are involved in this process. as information of chaperone expression in ad brain is limited, we aimed to study the expressional pattern of chaperones in several brain regions as this may be essential to understand how folding defects can lead to disease. we studied the concomitant expressional patterns of molecular chaperones in seven brain regions of adults with ad using two-dimensional polyacrylamide gel electrophoresis (2-de) and matrixassociated laser desorption ionization mass spectroscopy (maldi-ms). we unambiguously identified and quantified nine different chaperone proteins. six chaperone proteins, heat shock protein 60 (hsp 60), hsp 70 ry, heat shock cognate (hsc) 71, alpha crystallin b chain, glucose regulated protein (grp) 75 and grp 94 showed aberrant expressional patterns depending on brain region. hsp 70.1, grp 78 and t-complex 1 (tcp-1) epsilon subunit did not show any significant expressional change. these findings are compatible with neuropathological and biochemical abnormalities in ad brain and this report presents the first approach to quantify nine different chaperones simultaneously at the protein level in individual ad brain regions providing evidence for the relevance of aberrant chaperone expression to ad neuropathology. the mainstream approach to protein separation, visualisation and identification has been to use two-dimensional gel electrophoresis coupled to mass spectrometry for the identification of the separated proteins. however this approach is limited with the level of protein that may be loaded onto the 2d gel and the nature of the proteins that may be incorporated onto the first dimension (ipg strip). an alternative approach for the qualitative analysis of complex protein mixtures is the use of tryptic digestion followed by electrospray lc-ms/ms. this approach is dependent on a high degree of chromatographic separation prior to the mass spectrometer, such that ideally individual peptides are eluted into the source. if this is the case then the dynamic range of protein identification can be increased and low copy number proteins can be identified. often, however there is a large degree of redundant sequence information acquired, as in theory one peptide ms/ms spectrum is sufficient to identify a protein from a sequence databank. if a protein identification is obtained from a databank search of an ms/ms spectrum, it is potentially valuable to exclude the rest of the theoretical tryptic peptides to "mine" deeper into the protein complex being studied. we have introduced a new protein databank search engine capable of matching a tryptic peptide from the swissprot/ trembl databank to an ms/ms spectrum in one second. using this search engine we are able to generate dynamic tryptic peptide exclude and include lists, based upon the theoretical tryptic peptides from the identified protein, which can be passed to the acquisition software of our q-tof mass spectrometer in real time. thus, we are able to automatically steer the q-tof, during acquisition, to select and switch to the ms/ms mode only on those peaks that meet the modified selection criteria. experiments can be designed in which peaks that belong to a protein already identified during acquisition can be avoided. this exclusion list is based upon m/z, charge state and a user definable mass tolerance. the mass measurement of the data from the q-tof mass spectrometer is typically better than 10 ppm and as a consequence of this a tight mass tolerance can be selected, thus making the exclude list extremely specific. alternatively, in the case of samples derived from 2d gel spots, the mass spectrometer may abandon the current sample, re-equilibrate the lc column and move on to the next sample. to illustrate this methodology we show examples, both on standard samples and complex protein mixtures where q-tof data acquisition has been directed based upon the results from a databank search. this data will be compared and contrasted to data acquired in the normal automated lc-ms/ms mode. the specific anti-cancer activity of green tea (؊)-epigallocatechin-3-gallate (egcg) department of molecular biology, hebrew university-hadassah medical school, jerusalem, israel the effect of the green tea polyphenol-(ϫ)epigallocatechin-3-gallate (egcg) was tested in cultures of normal and transformed nih-patmras fibroblasts. in this system transformation can be induced at will by the addition of dexamethasone, which induces the expression of h-ras by activating the mammary tumor virus long terminal repeat (mmtv-ltr) promoter. this facilitates a reliable comparison of the susceptibility of normal and transformed cells to egcg. it has been shown that egcg inhibited the growth of transformed but not of the normal fibroblasts. in an attempt to elucidate the mode of the preferential inhibitory activity of egcg, its effect on growth promoting factors has been examined. the level of ornithine decarboxylase (odc, ec 4.1.1.17), which is a signal for cellular proliferation, was reduced by egcg in the transformed but not in the normal cells. egcg also showed strong inhibition of tyrosine kinase and mitogen-activated protein kinase (mapk) activities, without affecting the kinases in the normal cells. similarly, egcg also preferentially decreased the levels of the oncogenes ras and jun in transformed cell. egcg preferentially induced apoptosis in the transformed fibroblasts. in vitro chemosensitivity tests demonstrated that egcg inhibited the proliferation of leukemic cells. these findings suggest that egcg has a therapeutic potential in the combat against cancer. objectives: to develop a safo, affordable immune supportive therapy for hivϩ patients. design: a randomised, double blind, placebo-controlled study, testing an internationally patented l-methionine combination (lmc), in approximately 400 hivϩ patients; not yet on anti-viral treatment (cd4 count 200 to 500). methods: parameters measured included: cd4 count, total lymphocyte court, viral load, several clinical, as well as mechanistic parameters. the difference in the change from the baseline (active -placebo) was determined for each parameter. the study is ongoing. results: within 3 months, significant trends are noted. the cd4 count of the patients on the active therapy, presented with a slower rate of decrease, compared to the placebo group, mean difference (md) in this change from baseline; 15.1/cmm and 95% confidence interval (c1), this was confirmed by the total lymphocyte court values. after 12 months the placebo group was placed on active, causing the difference to disappear. conclusions: although further trials are needed, these results already indicate t-methionine as an important role player in the immune system of patients with impaired immune function. c. chiarla 1 , i. giovannini 1 , j. h. siegel 2 , g. boldrini 1 , and m. castagneto 1 1 centro di studio per la fisiopatologia dello shock cnr, catholic university, rome, italy 2 department of surgery, umdnj, newark, new jersey, u.s.a. in critical illness and sepsis, changes in amino acid plasma levels (aapl) have been assessed extensively, while little is known about the relationship with changes in other plasma components, such as those involved in fluid-electrolyte and osmotic balance; their investigation is also limited, in large clinical samples, by inter-patient variability. we analyzed the relationships between plasma sodium (na ϩ pl, meq/l) and aapl (µm/ l) in eighty consecutive measurements performed in one single patient with post-traumatic sepsis and severe, prolonged illness. unique feature of plasma taurine (tau) was maintenance of a highly significant inverse correlation with na ϩ pl (r 2 ϭ 0.48, p ͻ 0.001). all other aapl were correlated directly, or unrelated, to na ϩ pl, the only exception being a weak inverse correlation between tryptophan and na ϩ pl. tau was correlated, strongly and directly, also to phosphoethanolamine (pea), glutamate (glu) and aspartate (asp): tau ϭ 707.1 ϩ 7.3(pea) ϫ 4.6(na ϩ pl) r 2 ϭ 0.86, p ͻ 0.001 tau ϭ 710.2 ϩ 11.4(asp) ϫ 4.7(na ϩ pl) r 2 ϭ 0.61, p ͻ 0.001 tau ϭ 677.4 ϩ 30.7(logglu) ϫ 4.7(na ϩ pl) r 2 ϭ 0.59, p ͻ 0.001 and unrelated, or weakly and inversely related, to other aapl (measurements of beta-alanine were not included). co-variation of na ϩ pl and these aapl (particularly tau and pea) was influenced by severity of illness, and more complex regressions were needed to quantify this effect. these results provide useful information on interdependency of tau, na ϩ pl and other aapl in critical illness. the central nervous system (cns) shows an exceptionally high degree of vulnerability to reactive oxygen species. considerable evidence suggests that free radical formation and oxidative stress might play an important role in the pathogenesis of parkinson's disease (pd). moreover, it has been reported that the levels of glutathione and vitamin e increase in the brain of patients with pd as a compensatory mechanism to deal with oxidative stress. since vitamin e is an effective free radical scavenger in the brain, its neuroprotective function is the issue of new therapeutic approaches in neurodegenerative diseases. to elucidate the possible role of vitamin e in the pathogenesis of pd, we assessed the plasma levels of vitamin e, measured by high-performance liquid chromatography, in 54 patients with pd. vitamin e concentrations were also assessed in 93 age and sex matched normal individuals. the mean plasma levels of vitamin e did not differ significantly between these two groups (22.5 ϯ 8.15 mmoli/l for pd patients and 21.0 ϯ 7.9 mmoli/l for controls). the results of our study suggest that plasma vitamin e concentrations do not play a major role in the pathogenesis of pd. vitamin e and cardiovascular disease: nutritional and intervention approaches f. galli 1,2 1 institute of biological chemistry, university of urbino, italy 2 department of cardiovascular research, st thomas' hospital, london, u.k. vitamin e is represented by a family of eight natural vitamers (4 tocopherols and 4 tocotrienols) of which αtocopherol (α-t) form has the highest biological activity. this vitamin accounts for most of the lipid-soluble, chain-breaking antioxidant activity in mammalian tissues and plasma. in addition, it shows nonantioxidant properties through which it modulates cell signaling and the expression of specific enzyme in cell models playing a role in atherogenesis (e.g. endothelial and inflammatory cells). the preventive effect of vitamin e on acdv is still a matter of debate. the largest epidemiological investigations and 4 out of 5 main intervention studies at yet available have suggested a correlation between levels of vitamin e and incidence of atherosclerotic cardiovascular disease (acvd) and related mortality. an overall conclusion rising from these studies is that the major effect (if any) of vitamin e is to be found with intakes higher than 100 iu (100 mg all-rac α-tocopheryl acetate) per day. however, other investigations have failed to demonstrate a beneficial effect of vitamin e against acvd, suggesting the need for more studies on its metabolism and function. recently a family of tocopherol binding and transport proteins has been identified. they play a key role in the selective uptake and delivery of tocopherols to lipoproteins and tissues. genetic abnormalities of these proteins have been demonstrated to be responsible for conditions of vitamin e deficiency in humans. their tissue distribution and regulation are now under investigation. the information available on vitamin e metabolism and its response to supplements or diet changes are at yet poorly characterized. the synthesis of stable isotopes and the characterization of major metabolites of main vitamers provide important advances in this research. in the last years, both plasma levels and urinary excretion of relevant metabolites of α-t have been characterized. little information is available on metabolites formed by other vitamers. the emerging role of γ-t and its main catabolite 2,7,8-trimethyl-2-(b-carboxyethyl)-6hydroxychroman (γ-cehc) in the defense against nitrogen oxide species formed during the activation of inflammatory cells is now well established and suggests the need for further studies on the bioavailability and transformation of this homologue of vitamin e in humans. at the same time, an oxidation byproduct of α-t found in human plasma, namely α-tocopherylquinone, has been proposed to be also de novo synthesized from phenylalanine with a role in the genesis of a defective polyunsaturated fatty acid metabolism observed in phenylketonuric patients. this suggests a possible, and at yet unexplored relationship between vitamin e and phenylalanine/fatty acid metabolism which might have also a role in atherosclerotic process. r. gaspari 1 , s. mensi 1 , g. mercurio 1 , c. callà 2 , l. colacicco 2 , e. sacco 2 , and s. lippa 2 1 department of anaesthesiology and intensive care medicine, and 2 department of biochemistry and clinical biochemistry, catholic university of rome, italy four patients (3 females, 1 male; aged from 21 to 45 years) affected by severe liver failure, were treated by a new blood purification method, namely molecular adsorbent recycling system (mars). mars removes albumin-bound toxins using a specific membrane with a dialysate solution containing albumin. in the patients the plasma levels of methionine (meth), branched chain and aromatic amino-acids and liposoluble antioxidants were measured. the fischer's index did not show any significant variation, whereas the plasma levels of meth were well correlated with the levels of liposoluble antioxidants (vitamin e and coq10). in fact, in the patients receiving just branched chain amino-acids, the plasma levels of both meth and antioxidants progressively decreased. on the contrary, if meth and branched chain amino-acids were administered, the plasma levels of coq10 and vitamin e showed a positive correlation with the plasma meth levels (p ͻ 0.02; r ϭ 0.63 and p ͻ 0.005; r ϭ 0.77, respectively). since vitamin e and coq10 are mutually dependent-molecules, the administration of meth, essential substance for coq10 synthesis, may be effective to maintain a good antioxidant status in patients with severe liver failure undergoing mars treatment. we obtained new synthetic peptide preparation epitalon to be widely applied as a pharmaceutical due to its properties important in medical care. epitalon was found to stimulate repair processes in retinal diseases via restoring the retinal functions, in particular its photoreceptors. this promising peptide drug is a linear tetrapeptide of formula h-ala-glu-asp-gly-oh (alanyl-glutamyl-aspartyl-glycine). the substance was obtained by classic peptide synthesis in a solution (scheme: (1 ϩ 2) ϩ 1) with n-oxysuccinimide activated esters. coohgroups of lateral radicals of glutamic and aspartic acids were defended as benzyl esters, benzyloxycarbonyl (ala) and tert.butyloxycarbonyl (glu) n-defending groups were employed, deblockade conducted by trifluoroacetic acid and catalytic hydrogenolysis. preparative hplc on a reverse phase was applied for purification. the product was fully characterised by the data of analytical hplc (substance content -99%), amino acid analysis, ir-and hmr-spectra. the ready drug form is ampoules containing 10 µg of the substance in 1 ml of isotonic solution. epitalon application in patients with pigmented retinal degeneration stopped the pathology development in 100% and increased visual functions in 80% of the cases. in 70% of the patients visual acuity raised by 0.1-0.3. electroretinography confirmed the retinal functional activity increase. an increasing number of proteins are implicated in apoptosis and several of them have been shown to be altered in alzheimer's disease (ad) brain. because of this apoptosis is thought to be the underlying mechanism of neuronal cell loss in ad. to further substantiate this hypothesis we investigated the expression of a recently identified apoptosis related proteins and other apoptosis regulators in frontal cortex and cerebellum of ad by western blot and elisa techniques. quantitative analysis revealed unaltered levels of bax and raidd (receptor interacting protein associated ich-1 (caspase-2)/ ced-3 (caenorhabditis elegans death protease-3)-homologous protein with death domain) in both regions. zip (zipper interacting protein) kinase, bim/bod (bcl-2 interacting mediator of cell death/bcl-2 related ovarian death gene) and p21 were significantly increased only in ad frontal cortex (p ͻ 0.05, in all cases). cerebellar bcl-2 levels were significantly increased in ad (p ͻ 0.01) while in ad frontal cortex, although the levels tended to increase did not reach significance level. the results indicate that apoptosis indeed account for the neuronal loss in ad. however, it does not seem to involve bax and raidd. a. magyar 1 , m. brózik 3 , r. tóbi 1 , t. szabó 1 , j. szakonyi 2 , b. rojkovich 3 , p. gergely 2 , and f. hudecz 1 1 research group of peptide chemistry hungarian academy of science, budapest, 2 central laboratory of immunology, semmelweis university, budapest, and 3 national institute of rheumatology, budapest, hungary rheumatoid arthritis (ra) is a systemic autoimmune disease of unknown etiology. it is the most common of the inflammatory joint diseases, affecting 1-2% of the world population. anti-filaggrin antibodies (afa) directed against the epidermal protein, filaggrin, belongs to the most specific markers of ra. epitopes, containing citrulline within the sequence of filaggrin, have been recently identified as major antigenic sites recognised by afa. the aim of our study was to identify these epitopes of filaggrin derived-peptides targeted by ra specific antibodies to provide further information about the nature of the initial autoantigenic substance. the most immunogenic six sequences of filaggrin and further, on the n-and c-terminal, shortened version of the original peptide ( 306 shqestrgrsrgrsgrsgs 324 ) were synthesized. we used conventional solid-phase peptide synthesis (fmoc strategy) carried out on "multipin ncp" noncleavable kit. in elisa experiments the presence of afa was deter-mined using serum samples of ra patients and healthy blood donors. in conclusion our results provide further evidence that not simply the presence of citrulline but also the nature of its surrounding amino acids have important role in the creation of autoantigenic epitope reactive with anti-filaggrin antibodies. the autoimmune nature of multiple sclerosis (ms) has introduced cytokine genes as logical candidates for the loci determining susceptibility to the disease and/or influencing disease progression. interleukin (il)-1alpha and 1beta are major proinflammatory cytokines that have been related with several chronic inflammatory diseases such as ms. the il 1-receptor antagonist (il-1ra) is a protein structurally related to il-1beta that effectively inhibits the proinflammatory effects of il-1. a polymorphism in the 5ј-flanking regulatory region at ϫ889 of the il-1alpha gene, which may cause an overexpression of il-1alpha and a variable number tandem repeats (vntr) polymorphism in the il-1ra gene have been also associated with several inflammatory diseases. two biallelic base change polymorphisms in the il-1beta gene have been reported to influence the protein production: one is located in the promoter region at position ϫ511 and the other is in exon 5 at position ϩ3953. to analyze the contribution of il-1alpha, il-1beta and il-1ra genes in the genetics predisposition to ms, we have examined four polymorphic genetic markers in 132 italian patients with clinically definite ms and 130 healthy controls. in summary, no significant differences in genotypes and allele frequencies were found between ms patients and healthy controls. fibronectin -the extracellular matrix protein is oxidatively modified with oxygen reactive species (ros) in inflammation site. activated neutrophiles release the hypochlorite acid (hocl) and chloramines as products of myeloperoxidase/ h 2 o 2 /cl ϫ system. these reactive chlorine species chlorinate in turn matrix proteins. the resulting changes of tertiary protein structure could be evaluated by monitoring the antigen/antibody complex formation. the formation of the complexes between native/chlorinated fibronectin and igg class antibodies were examined by means of elisa with luminol chemiluminescence detection. the degree of fibronectin modification was monitored with spectroscopic methods. since the oxidation leads to the fibronectin aggregation -the tryptophane contents in resulting aggregates were evaluated with stern-volmer approach (acrylamide quenching). moreover, the aldehydes influence on the ag/ab complex formation was examined -since aldehydes are known products of amino acids n-chloramines deamination. also the native and modified fibronectin adherence to the matrix proteins was monitored with use of hrp labeled antifibronectin antibodies. the preliminary results suggest that chlorination impairs the ab/ag complex recognition but also prove that igg bounded chlorinated fibronectin promotes igg clusters formation. it was found also that mm concentration of the serine derived glycoaldehyde decreases the fibronectin/igg recognition and the effect could be attributed to the igg aggregates formation. we demonstrate also that hrp-labeled iggs detect the collagen and fibrynogen adherent fibronectin in a dose dependent manner-details of the elisa method are discussed. in subjects with rheumatoid arthritis (ra) oxidized low density lipoproteins (ldl) are supposed to serve as mediators for joint damage, further exacerbating the inflammatory process. to better understand mechanisms of ldl oxidation in ra a specific marker of oxidative modification of apolipoprotein (apo) b-100 proline and arginine residues, 5hydroxy-2-aminovaleric acid (hava), had been measured in plasma and synovial fluid ldl subfractions (ldl 1 , svedberg units (s f ) 7-12 and ldl 2 , s f 0-7) by gc-ms. paired knee synovial fluid and plasma samples were collected from 10 subjects with ra. additionally, plasma samples were collected from 10 healthy controls. the ldl 1 hava content in plasma was not different between the groups (ra, 0.004 ϯ 0.001 vs controls, 0.004 ϯ 0.001 mol/mol apob-100, p ϭ 0.748). the ldl 2 hava content in plasma was significantly higher in ra (0.145 ϯ 0.051 vs 0.013 ϯ 0.002 mol/mol apob-100, p ϭ 0.000). furthermore, synovial fluid ldl 1 and ldl 2 in ra contained elevated hava levels when compared with plasma concentrations (ldl 1syn , 0.023 ϯ 0.012 mol/mol apob-100 (p ͻ 0.001) and ldl 2syn , 0.434 ϯ 0.129 mol/mol apob-100 (p ͻ 0.001)). results suggest that proline and arginine residues of apob-100 are highly reactive toward oxygen radicals in both plasma and synovial fluid in ra. furthermore, susceptibility of apob-100 to oxidative modification increases along the lipoprotein metabolic cascade. particularly small dense ldl 2 were prone to direct oxidation of apob-100. correlation between hava content in plasma and synovial fluid ldl 1 and ldl 2 in ra may allow the use of hava as a clinical marker of antioxidant barrier impairment in ra. vascular collagen accumulation contributes to development of hypoxic pulmonary hypertension (ph). we have shown that injections of a polymer of the proline analogue cis-4-hydroxy-l-proline (chyp) in liposomes attenuated acute ph in rats (ajrccm 1997; 155 : 1384) . we now treated rats with established ph with a new polymer containing an increased "payload" of chyp. chyp was conjugated to a low mw poly(ethylene glycol)-lysine carrier {poly (peg1000)-lys-chyp} to increase the % by wt of the analogue. rats were exposed to 10% o 2 for 7 da to induce ph. on da 0, 7 and 14 after 7 da of hypoxia, animals were injected iv with chyp polymer in liposomes (hc) or bioinactive trans-hyp polymer in liposomes (ht). air controls received thyp polymer in liposomes (at). at 0 and 21 da, we measured mean right ventricular pressure (rvp) and hydroxyproline (hyp) content in main pulmonary arteries. on da 0, rvp (mmhg) was 9 ϯ 1 and hyp (µg/vessel) was 88 ϯ 6 in at. rvp and hyp increased to 17 ϯ 1* and 139 ϯ 4*, respectively, in hypoxic animals (n ϭ 4; *p ͻ 0.05 vs. at). on da 21, rvps were at 10 ϯ 1, ht 24 ϯ 1*, hc 15 ϯ 1* †; hyps were at 91 ϯ 9, ht 176 ϯ 15*, hc 122 ϯ 1* † (n ϭ 4; *p ͻ 0.05 vs. at; †p ͻ 0.05 vs. ht). from da 0 to 21, rvp did not increase and hyp decreased in the hc group vs. ht. we conclude that weekly injections of polymeric chyp prevented progression of established hypoxic ph and reversed hyp accumulation. targeted delivery of antifibrotic polymers may prevent and reverse the progression of ph. (support: phs, barbara cornwall foundation). glucosinolates are amino acid-derived natural plant products found throughout the capparales order, which includes agriculturally important crops such as oilseed rape, brassica vegetables and the model plant arabidopsis. glucosinolates and their degradation products have a wide range of biological activities, e.g. in plant defense as deterrents against insect and fungi and as attractants to insects that are specialized feeders in brassicaceae. the conversion of amino acids to oximes is a key step in glucosinolate biosynthesis. we have recently shown that cytochromes p450 belonging to the cyp79 family catalyze the conversion of aliphatic, aromatic as well as indole amino acids to the corresponding oximes. cyp71e1 catalyzes the oxime-metabolizing step in the biosynthesis of the cyanogenic glucoside dhurrin. we have recently shown that the oxime-metabolizing enzyme in the glucosinolate biosynthetic pathway is a cytochrome p450 homologous to cyp71e1. the post-oxime enzymes in the glucosinolate pathway have high substrate-specificity for the functional groups, and low substrate-specificity for the side chain. therefore, we have been able to metabolically engineer new glucosinolate profiles into arabidopsis by altering the level of endogenous cyp79s and by introducing new cyp79s. the approach has great potential for design of "biotech crops" with improved pest resistance and increased nutritional value. hypercalcemia as a potential threat in the dietary treatment of maternal phenylketonuria f. eyskens 1 and s. beernaert 2 1 pediatrician, metabolic diseases and 2 dietitian, azm-koningin paola childrens hospital, metabolic lab pcma, antwerp, belgium over 90% of infants born to mothers with blood phenylalanine (phe) concentrations above 1200 µmol/l exhibit evi-dence of foetal dammage, low birth weight, microcephaly, dysmorphic facies, slow postnatal growth and development and long-term intellectual impairment. keeping maternal phe concentrations below 250 µmol/l before conception and throughout pregnancy reduces significantly the risk of abnormalities in the offspring of women with phenylketonuria (pku). we describe a woman, 31 years old, who showed phe blood levels of 150-200 µmol/l under a strict diet (total protein content of 1.13 g/kg body weight/day with 0.54 g/kg natural proteins and 0.59 g/kg proteins provided by the aminoacid mixture pku3 (milupa, germany); 1,655 cal/day) at the beginning of her first pregnancy. the first weeks she developed vomiting which gradually increased in severity. at 8 weeks of pregnancy, she had diarrhea, severe bouts of vomiting and manifested a deficient nutritional status with intake of 0.2 g/kg bw proteins and 1,178 cal/day. she was hospitalized to start refeeding using continue drip feeding administered by nasogastric tube. after 2 days on this regimen she developed vomiting, heart palpitations and mental confusion. her serum calcium level, that was normal at admission in the hospital, showed an elevation to 6.5-7 meq/l (ref. value 4.2-5.1 meq/l). the feeding was stopped immediately and under an intravenous infusion and gradually introducing a feeding composed of pku3, carbohydrates and mct fats the serum calcium and the blood phe levels dropped to normal values. and volatile components of caramel obtained by heating commercial maltose solution for different time intervals. one sample containing maltose only was used as control, the caramelization was conducted at 130c° for total time period 90 minutes and subjected to sensory analysis and isolation of volatile components. the odour and colour sensory tests were evaluated according to the international standard methods (iso). the results showed that addition of lysine as a catalyst gave rise to a significant (p ͻ 0.05) increase in intensity of the whole flavour in comparison with the control sample. the sweet and caramel notes, the most characteristic attributes of caramel, showed remarkable increase. on the other hand the increase in heating time in presence of lysine as a catalyst resulted in high significant increase in browning rate of caramel solution. the volatile components of each sample were isolated by using the new technique, solid phase microextraction (spme) and subjected to gc and gc-ms analysis. over 250 volatile components were separated, however only the most important component for caramel flavour were reported. maltol and 5hydroxymethyl-2-furfural (hmf) and 4. h-pyran-4-one,2,3dihydro-3,5-dihydroxy-6-methyl (dihydro dihydroxy maltol), the main characteristic caramelization products were present in high concentration in samples contaning lysine heated for 60 minutes. in addition one pyrazine was only identified in the samples contaning lysine. a comparative study between the present results and those of our previous study concerning addition of alanine as a catalyst was carried out. short-term exposure of human umbilical vein endothelial cells (huvecs) to hyperglycemia increases l-arginine transport (system y ϩ /cats) and nitric oxide (no) production (via enos). it has been reported that enos could also be activated by a ca 2ϩ -independent mechanism involving phosphorylation of ser 1177 by a phosphatidylinositol 3-kinase (pi3-kinase) dependent pathway. we investigated the involvement of pi3kinase on the stimulatory effect of acute hyperglycemia on enos and l-arginine transport in huvecs. l-arginine transport, no synthesis and phosphorylation of ser 1177 in enos were increased by d-glucose (25 mm, 2 min). similar results were obtained in huvecs exposed to insulin. incubation of cells with wortmannin (pi3-kinase inhibitor) prevented the effects of d-glucose and insulin. no changes in the intracellular ca 2ϩ and enos protein levels were detected. thus, acute hyperglycemia increases l-arginine transport and enos activity through a pi3-kinase dependent, ca 2ϩ independent mechanism in huvecs. [ the hypercalcemia in this patient was due to a very high content in calcium of the feeding administered (2-3 times the adh value) associated with a high vitamine d concentration (see table) and a clinical state of dehydratation. the further pregnancy was uncomplicated and a healthy girl was born who developed normal. • the aminoacid mixtures used in the treatment of pku contain a high level of calcium, phosphate, magnesium and iron. they also contain a high concentration of vitamine d. • nutritional monitoring of pregnant pku patients should include the calcium, phosphate, iron, zinc and vitamins status. • vitamins a and d suppletion is contraindicated in these patients based on the high concentrations of these vitamins in the aminoacid mixtures used in the dietary treatment. flavour and aroma chemistry department, national research centre, dokki, cairo, egypt caramelization of various carbohydrates leads to product with a high tinctorial strength provided by different additives catalyzing the process. the present study was conducted to evaluate the catalytic effect of lysine on the sensory attributes administered pku3 (80 g ϭ adh 1, 2 g/kg/bw) lipoic acid is a prosthetic group of h-protein of the glycine cleavage system and e2 components of the pyruvate, 2oxoglutarate and branched-chain 2-oxoacid dehydrogenase complexes. in mammals, attachment of lipoic acid to these proteins requires two enzymes. lipoate-activating enzyme (lae) catalyzes the activation of lipoate to lipoyl-nucleoside monophosphate. then, lipoyltransferase transfers the lipoyl moiety to the specific lysine residue of the proteins. we purified lae from bovine liver mitochondria. lae activated lipoate with gtp at a 1000-fold higher rate than with atp. the reaction absolutely required lipoate and mggtp, and the reaction product was lipoyl-gmp. lae activated both r-and senantiomers of lipoate to the respective lipoyl-gmp although preference for r-lipoate was observed. lipoyltransferase equally transferred both r-and s-lipoyl moiety from respective activated lipoate to apoh-protein. however, only h-protein carrying r-lipoate was active in the glycine cleavage reaction. cdna clones encoding a precursor lae with a mitochondrial presequence were isolated. amino acid sequence of lae was identical with that of xenobiotic-metabolizing/medium-chain fatty acid : coa ligase-iii, but an amino acid substitution due to snp was found. these results indicate that the medium-chain acyl-coa synthetase in mitochondria plays a novel function with gtp, the activation of lipoate. instituto di chimica biologica "g. fornaini", università di urbino, italy nitric oxide (no) can modulate red blood cells (rbc) glycolysis by translocation of the enzyme glyceraldehyde-3phosphate dehydrogenase (gapd) [e.c. 1.2.1.12] from the cytosolic domain of the membrane protein band 3 (cdb3) in the cytosol. in this study we have investigated which no-reactive thiols might be involved influencing gapd translocation, and which is the role of glutathione (gsh) in this context. two highly reactive cys residues (k 2 ϭ 73.7 m ϫ1 s ϫ1 and 101.5 m ϫ1 s ϫ1 , respectively) were identified by transnitrosylation with nitrosoglutathione (gsno) of cdb3 and gapd. the cys 149 in the catalytic site of gapd is exclusively involved in this gsno-induced nitrosylation. reassociation experiments carried out at equilibrium with preparations of rbc membranes and gapd revealed that different no-donors may form ϫsno on, and decrease the affinity between, gapd and cdb3. in intact rbc, both the no-donors 3-morpholino-sydnonimine (sin-1) and peroxynitrite (onoo ϫ ) significantly increased gapd activity in the cytosol and glycolysis measured as lactate production and energy charge levels. however, we obtained data suggesting that onoo ϫ is the main no-derivative able to cross the rbc membrane leading to gapd translocation and ϫsno formation. both in cell-free experiments and intact rbc, diamide (a thiol oxidant able to inhibit gapd activity) was observed to reverse the effect of sin-1 on gapd translocation. the results demonstrate that cdb3 and gapd contain reactive thiols that can be transnitrosylation mainly by means of gsno, these can ultimately influence gapd translocation/ activity and the glycolytic flux. abteilung für allgemein-viszeral-und gefässchirurgie, kliniken dr. erler gmbh, nürnberg, germany new surgical procedures like minimal-invasive-surgery brought many advantages for the surgical patient: less pain and shorter hospitalization. regarding nutrition, patients gets normal food on the ward still on the operation-day and need only saline-infusions overnight for fluid and electrolyte substitution but no hypocaloric parenteral nutrition. hypocaloric parenteral nutrition had been developped as a peripheral intravenous nutritional concept for patients with a normal body mass index over a period not longer than 4-5 days. multiple clinical studies showed that bowel movements increase earlier after an early postoperative enteral feeding which allows an earlier discharge of the patient. the result is a remarkable decrease of costs and an increase in patient benefit. still some years before surgeons preferred in visceral surgery parenteral nutrition over a period of 4-5 days under the opinion not to stress an anastomosis. this opinion changed in the last years under the aspect that about 1,000-1,500 ml of bile fluid, 1,000-1,500 ml pancreatic juice and 1,000-1,500 ml gastric juice per day are passing a small intestine anastomosis without any complications. concerning colon-anastomoses, the colon is preoperatively washed out, so it lasts until 5 days until defecation. multiple studies also showed a benefit for the patient regarding immunostimulation by early postoperative enteral feeding. conclusion: in our hospital with 244 surgical patients we recommend postoperatively either early normal enteral feeding or a high caloric parenteral nutrition if parenteral nutrition is needed for longer than 5 days. if artificial nutrition is necessary for more than 14 days we recommend enteral nutrition given by a tube or peg (percutaneous endoscopic gastrotomy). department of food technology, national research centre, dokki, cairo, egypt in the near east, "frekeh" has been known for many centuries as a stable food made from wheat. it is generally claimed that "frekeh" is better than wheat regarding its storage stability. the protein quality of parched immature durum wheat (frekeh) produced from 2 variety was evaluated. frekeh from four maturing levels during the dough stage of the seed development, were analyzed for approximate analysis. results showed that "frekeh" produced at the beginning of the dough stage was of better nutritional value than that produced at the following maturity levels, since the former was higher in protein, fat, minerals and crude fiber as well as in reducing sugar content. in addition, it was shown that these results confirm well with the sensory quality evaluation of the cooked product. further more, it was found that the cooking time was suitable to produce a "freqkeh" meal with high levels of acceptability. the observed decrease in protein content with increasing maturity level raised the question of how the protein quality of "frekeh" versus that of nature wheat grains varied. in this investigation, the amino acid of "frekeh" was determined. dietary treatment and carnitine supplementation has greatly improved long-term outcome of patients with ppa and (vitamin b12 unresponsive) mma. however, metabolic decompensation may be frequent and final outcome in most patients show various handicaps. to investigate the usefulness of measuring free carnitine and acylcarnitines in dried blood by tandem mass spectrometry, we investigated 9 patients with ppa and 5 with mma in a period of 8 months by weekly capillary blood punctures performed by the parents. age of the patients were from 0.5 until 18 years. clinical status at the time of blood drawing was evaluated by regular phone calls. free carnitine in all patients substituted by oral carnitine treatment (50-100 mg/kg/day bw) was normal. the parameter best reflecting clinical status was the c 3 /c 16 -acylcarnitine quotient. mean value in mma and ppa patients showed a range of 11.5-29.4 (normal 1.5 ϩ/ϫ 0.36, n ϭ 18), there was no difference between ppa and mma patients. individual mean values of the patients significantly increased when the patient was ranked higher in the clinical score system or during decompensation. since measurement of acylcarnitines in dried blood by tandem mass spectrometry is easy to perform, this method may be used for home monitoring of patients with mma and ppa. influence of acute treatment with 1,2,3,4tetrahydroisoquinoline on the levels of glutathione and reactive oxygen species, and on the enzymatic activity of γ-glutamyl transpeptidase in dopaminergic structures of rat brain e. lorenc-koci 1 , m. sokoĺowska 2 , m. zapaĺa 2 , and l. wĺodek 2 1 institute of pharmacology, polish academy of sciences, kraków, and 2 institute of medical biochemistry, collegium medicum, jagiellonian university, kraków, poland 1,2,3,4-tetrahydroisoquinoline (tiq) and its derivatives generated considerable interest as molecular species that may be implicated in the pathogenesis of parkinson's disease (pd). in pd, apart from the lack of dopamine in the striatum, a decreased concentration of glutathione (gsh) is found in the substantia nigra (sn). it is also known that gsh depletion potentiates the toxicity of mptp and 6-hydroxydopamine. however, there are no data available on the tiq influence on gsh metabolism. the aim of the present study was to exemine the effect of acute tiq administration on the levels of gsh and reactive oxygen species (ros), and on the enzymatic activity of γ-glutamyl transpeptidase (γ-gt) in dopaminergic structures of rat brain. the investigation was carried out 4 h after a single dose of tiq (100 mg/kg i.p.). at that time, a marked increase in the tissue gsh level and simultaneous significant inhibition of γ-gt were found in the structures studied. in tiq-treated rats, the production of ros was reduced in the sn, but it was markedly enhanced in the striatum. our results suggest that the increase in gsh level in dopaminergic structures stems from inhibition of γ-gt and refers to the extracellular pool of this peptide. apparently, the tiq-mediated alterations in the levels of gsh and ros may have some implications for the etiology of pd. tetrahydrobiopterin-responsive phenylalanine-hydroxylase deficiency with mutations distant from the tetrahydrobiopterin binding site z. lukacs 1 , r. steinfeld 1 , a. kohlschütter 1 , j. zschocke 2 , and k. ullrich 1 1 department of pediatrics, university of hamburg, and 2 university-children's hospital, heidelberg, germany phenylalanine hydroxylase (e.c. 1.14.16.1) catalyzes the hydroxylation of phenylalanine to tyrosine in the presence of oxygen and the cofactor (6r)-l-erythro-5,6,7,8tetrahydrobiopterin (bh 4 ). mutations in the phenylalanine hydroxylase gene may cause phenylketonuria or hyperphenylalaninemia. alternatively, disorders in bh 4metabolism also result in an increase in phenylalanine concentrations but simultaneously affect other bh 4 -dependent enzymes, consequently, causing a severe neurological disorder. recently, several patients with a phenylalanine-hydroxylase deficiency but with normal bh 4 -metabolism were reported who showed a significant decrease in blood phenylalanine concentrations upon treatment with bh 4 . indeed, two such patients in our hospital were also sensitive to daily oral doses of 5-10 mg bh 4 /kg. the subsequent molecular genetic analysis revealed that patient 1 was homozygous for the widespread mutation y414c and patient 2 was compound heterozygous for the mutations a104d and k320n. it is striking, that all mutations are located distant from the known bh 4 -binding site and thus, should not be associated with bh 4 -sensitivity. additionally, further patients who share the same genotype are not sensitive to bh 4 . therefore, it must be concluded that factors independent of the phenylalanine hydroxylase gene, like e.g. individual chaperone proteins, influence the three-dimensional structure of the enzyme and thereby, enhance enzymatic activity in the presence of elevated concentrations of bh 4 . retrotransposons are structurally similar to retroviral gag and pol which are required for their replication via reverse transcription, and seem to be an ancestral form of specialized retroviruses. reverse transcription of retrotransposons was assumed to occur in virus-like particles as well as in retroviruses. rna-packaging in this particles suggests a possibility of infection. presumably, the formation of functional virus-like particles requires the interaction of gypsy rna with a protein encoded by gypsy first open reading frame (orf1) or a product of its processing. the objective of this work was to study whether the protein by this frame can bind with nucleic acids similarly to retroviral gag-protein and how phosphorilation of that protein may influence to this interaction. then gypsy orf1 was cloned and expressed in escherichia coli, and its protein product was purified by ion-exchange chromatography on deae-cellulose and affinity chromatography on heparin-sepharose and tested electrophoretically. it was shown that recombinant protein bound with its own mrna and with dna. the affinity for ssdna bing higher than for dsdna. the binding constant was estimated with rna. the method utilizes the ability of nitrocellulose to bind proteins but not nucleic acids. binding of 50% gypsy rna was achieved with about 100 ng of the protein in 50 ml of the reaction mixture. the binding constant was 5× 108 m-1, which is consistent. the structure of the putative nucleic acid-binding domain suggests that the protein is more similar to the core proteins of spumaviruses of the family retroviridae that to those of other retroviruses. phosphorilation of gag-like protein encoded by first open reading frame of retrotrasposon gypsy (mdg4) affects to interaction with nucleic acid. tryptophan (trp) in humans is catabolized by several pathways leading to various metabolites of kynurenine and indolic compounds formation. a number of diseases are connected with abnormalities in its excretion, but relationship of cause and effect is usually unclear. we introduced a two-step procedure for the detection of defects in metabolism of trp: 1) tlc is employed when starting the investigation, 2) two hplc methods were proposed and used at the next step, when pathological findings are to be proved and the individual metabolites quantified. the first hplc procedure enables the assessment of tryptophan, indolylacry-loylglycine (iag) and other five indolic compounds. the second method is intended to the monitoring of kynurenine and seven of its catabolites. the same sep-pack pre-treated sample of plasma and urine is used for all methods. the reference values and the excretion pattern in some groups of patients (350 in total) were assessed. hepathopathy, gastrointestinal defects, myopathy and seizures with other neurological symptoms were the conditions connected with changes in the excretion of some metabolites of trp. significant decrease of iag excretion was found in burn patients early after the injury. urine analyses were performed at patient with hartnup disease and benign xanthurenic aciduria, inherited metabolic defects of trp. in other experiments, trp effect on the decarboxylation of other aromatic amino acids in the liver was investigated; only weak inhibition under physiological conditions was recognised. ( two hypothetical proteins of escherichia coli, ybbq and yhae, show high sequence similarity to d-threonine dehydrogenase from pseudomonas cruciviae ifo 12047. we cloned each gene encoding ybbq and yhae into e. coli jm109. both ybbq and yhae showed no d-threonine dehydrogenase activity and showed significant activities for d-serine in the presence of nad. ybbq and yhae were purified to homogeneity from the e. coli clones. ybbq consisted of two identical subunits with a molecular mass of 31 kda, whereas yhae was a tetramer (native molecular mass, 124 kda). ybbq showed the maximum activity at ph 11.0 for the oxidation of d-serine. whereas optimum ph of yhae was ph 10.5. they catalyzed oxidation of glycerate and 3-hydroxyisobutyrate. d-glycerate was the best substrate for both enzymes. both enzymes also catalyzed reduction of tartronate semialdehyde in the presence of nadh. at physiological ph, the rate of tartronate semialdehyde reduction was much higher than that of d-glycerate oxidation. the ybbq gene is in the operon of glyoxylate utilization and the yhae gene is in the operon for d-glucarate/galactarate utilization. these results suggest that both ybbq and yhae are dglycerate 3-dehydrogenases and function physiologically in conversion of tartronate semialdehyde into d-glycerate. a serine protease inhibitor model: synthesis and biology z. mucsi 1 , á. bódi 2 , l. gráf 2 , a. perczel 1 , a. patthy 3 , and g. orosz 4 1 department of organic chemistry, 2 biochemistry, eötvös university, budapest, 3 agricultural biotechnology centre, gödölló´, and 4 research group of peptide chemistry, hungarian academy of sciences, budapest, hungary sgci is structurally related to the pmpd-2 family of canonical serine protease inhibitors. in these peptides, there is a p1-p1ј position which is responsible for reversible binding to chymotrypsin. their structure is characterized by structural compactness: the molecule contains three -sheets and three disulfide bonds. in the sgci molecule the p1-p1ј corresponds to lys-leu bond, which is cleaved by chymotrypsin extremely slowly. the question arises why an excellent substrate behaves at the same time as inhibitor. it was assumed that the threedimensional structure of the molecule is responsible for the inhibitory activity. a model was designed to include all the known features of the inhibitor: the structurally necessary -sheet structure and the fragment containing the p1-p1ј environment. three model peptide were synthesized. two model peptides had no inhibiting effect and were cleaved by chymotrypsin. one of the cleavage points is the expected p1-p1ј position, while the other positions found to be chymotrypsin preferred positions after the first cleavage. the three-dimensional structures of the model peptides were mapped by nmr. on the basis of nmr structures obtained it has been shown that the cyclopeptide part is more flexible in the models than in sgci. the initial process in the reaction mechanism of a bisubstrate enzyme, rat mercaptopyruvate sulfurttransferase: inactivation study by using chloropyruvate n. nagahara 1 , t. nakagawa 2 , and m. minami 1 1 department of hygiene and public health, nippon medical school, sendagi bunkyo-ku, tokyo, japan 2 institute for organic chemistry, darmstadt university of technology, darmstadt, germany to investigate the reaction mechanism of a bisubstrate enzyme, rat mercaptopyruvate sulfurtransferase (ec 2.8.1.2, mst), inactivation kinetics with 3-chloropyruvate (chloropyruvate) was studied; each inactivation reaction was completed in a preincubation procedure. chloropyruvate is an analog of 3-mercaptopyruvate (mercaptopyruvate) and irreversibly inhibits mst. the inactivation depended on incubation time and the concentration of chloropyruvate and showed saturation kinetics. the plot for the logarithm of % activity remaining versus preincubation time showed pseudo-first-order. the kinact is 8.0 ϫ 10 ϫ2 min ϫ1 and k1 is 3.1 mm. these suggest that chloropyruvate serves as a mechanism-based inactivator. mercaptoethanol , so that chloropyruvate can approach cys247 via the donor substrate route and acceptor substrate one, and a ternary complex may be formed prior to the inactivation. these findings suggest that a donor substrate enters the catalytic cavity prior to an acceptor one in the initial process of the mst reaction: mst follows an ordered sequential mechanism. polyketides are natural products of bacteria, fungi, marine organisms and higher plants, many of which have clinical usage. actinorhodin (1) is an antibiotic produced by streptomyces coelicolor via an iterative type ii polyketide synthase (pks) system. this consists of a multi-enzyme complex with a single catalytic function for each enzyme. departments of 1 chemistry and 2 pediatric surgery, school of medicine, fujita health university, toyoake, japan it has been reported that, in rats with a single intoxication of α-naphthylisothiocyanate (anit), acute liver injury develops with enhanced lipid peroxidation and neutrophil infiltration in the liver tissue. melatonin functions as an antioxidant. melatonin is known to inhibit neutrophil infiltration into damaged liver tissues. therefore, we examined whether melatonin exerts a protective or preventive effect on anit-induced acute liver injury. male wistar rats received a single i.p. injection of anit (75 mg/kg) and oral administraton of melatonin (100 mg/kg) at 12 or 24 h after anit injection. animals administered with melatonin at 12 and 24 h after anit injection were sacrificed 24 and 48 h, respectively, after the injection. liver injury appeared 24 h after anit injection and developed at 48 h. melatonin administered at 12 h after anit injection prevented liver injury formation with attenuation of increases in hepatic lipid peroxide level and myeloperoxidase activity, an index of neutrophil infiltration. melatonin administered at 24 h after anit injection prevented liver injury development with attenuation of further increase in hepatic lipid peroxide level. thus, melatonin protects against and prevents anit-induced acute liver injury in rats possibly through its antioxidant action and/or its inhibitory action against neutrophil infiltration in the liver tissue. k. okamura-ikeda, s. katayama, k. fujiwara, and y. motokawa t-protein is a component of the glycine cleavage system and catalyzes the tetrahydrofolate-dependent reaction. mutation in human t-protein (ht) gene results in clinical nonketotic hyperglycinemia (nkh). eight point mutations have been identified so far in nkh patients with t-protein deficiency. to understand the structure and function of ht, the wild-type (wtht) and three mutant t-proteins (g47r, g269d and r320h) were expressed in escherichia coli with chaperons groel and groes which facilitated the recovery of the expressed proteins as a soluble form. levels of expression of these proteins were similar but the recovered soluble forms of mutants were about one-third of wtht. g47r showed comparable specific activity to wtht, whereas g269d and r320h mutants exhibited remarkable reduction in specific activity. since homoallelism for g269d mutation and heteroallelism for g47r and r320h mutation were identified in typical and atypical nkh, respectively, these results suggest that g269 and r320h mutations are highly deleterious in the aspects of not only protein folding and/or stability but also catalytsis. on the other hand, g47r mutation might affect mainly on the protein stability. detailed characterization of these mutants is now in progress. laboratory of animal nutrition and biochemistry, miyazaki university, miyazaki-shi, japan the minimal actinorhodin pks, shown in black below, consists of the ketosynthase (ks), chain length factor (clf) and acyl carrier protein (acp) and is the minimum set of enzymes required for polyketide production. we have investigated the stoichiometry of the ks-clf complex and the ks-clf:acp minimal system using three methods: 1. native gel electrophoresis. 2. cross-linking of proteins using dibromoacetone. 3. radical cross-linking of proteins. this new method has also been used with wild type s. coelicolor cell free extract with 10% ks-clf in order to elucidate which proteins are in close proximity to ks-clf during in vitro actinorhodin production. in ruminant animals, essential amino acids have never been completely established, because of the difficulty of its estimation due to the presence of microorganisms such as bacteria and protozoa in the first stomach called rumen. in our previous paper, histidine was shown to be the first limiting amino acid in the rumen contents when evaluated by chemical score. recently we have also reported that rumen microorganisms cannot synthesize histidine from histidinol. on the other hand, there have been some reports which showed that nitrogen balance of ruminants was not improved by supplementation of histidine to rumen microbial protein together with methionine, lysine and threonine which had been known to improve. based on these facts, we have a hypothesis that histidine may not be an essential amino acid for ruminants. in the present paper, we will report about the abilities of cattle liver and kidney to synthesize histidine from histidinol comparing with those of swine liver and kidney. the ability was demonstrated by examining the activities of histidinol dehydrogenase (crude enzyme) by means of direct measurement of an increase in histidine and decrease in histidinol. the amount of histidine produced from histidinol by the enzyme seemed sufficient for meeting the histidine requirement of cattle. the browning reaction is the sequence of events which begins with the reaction of amino group in amino acids, peptides or proteins with glycosidic hydroxyl group of sugars; the sequence terminates with the formation of brown nitrogenous compounds or melanoidines. this reaction gives rise to tremendous number of components such as volatile alcohols, ketones, aldehydes, esters, ethers and sulfur and nitrogen containing heterocycles in addition to nonvolatile amadori compounds and complex brown pigments of medium to high molecular weights. the present study was designed to choose a currently occurring system (aspartic acid -fructose) as a model system, since aspartic acid was found to be one of the most important amino acids in many kinds of food varieties. the reaction was done under controlled conditions of reactants ratios, temperature and time. the reaction mixtures were subjected to successive extractions with suitable solvents where the obtained corresponding flavour concentrates were thoroughly investigated. the results indicated different classes of compounds such as aldehydes, furans, alcohols and alkylated pyrazines varying in quantities depending on the reaction conditions. these products were also investigated concerning their toxicological effects. so, such products of nonenzymatic reactions showed different chemical and biological properties. purification and characterization p. piyarat 1 , s. nagata 2 , h. misono 2 , and k. packdibamrung 1 1 department of biochemistry, faculty of science, chulalongkorn university, bankok, thailand 2 department of bioresources science, faculty of agriculture, kochi university, nankoku, kochi, japan nad ϩ dependent alanine dehydrogenase was purified 100 fold to homogeneity from aeromonas hydrophila. molecular mass of 230,000 daltons was estimated for alanine dehydrogenase by sephadex g-200 chromatography. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified en-zyme showed 1 polypeptide band with molecular mass of 40,000 daltons, indicating that the enzyme is hexamer. the enzyme is highly specific for alanine and nad ϩ . sulfhydryl group of the enzyme plays an important role in the catalysis. the enzyme retained its activity on heating at 55°c for 16 h. optimum ph for reductive amination and oxidative deamination were 8.0 and 10.5, respectively. the steady state kinetic studies including product inhibition on the enzyme reaction indicated that the oxidative deamination proceeds through a sequential ordered binary-ternary mechanism in which nad ϩ binds first to the enzyme followed by l-alanine and products are released in the order of pyruvate, ammonia and nadh, respectively. the k m values for nad ϩ , l-alanine, pyruvate, ammonia and nadh were 0.17, 20, 1.33, 77 and 0.25 mm, respectively. an elevation of apolipoprotein (apo) b-100 concentrations is a particular feature of several metabolic disorders, such as type 2 diabetes (t2d), impaired glucose tolerance (igt), and familial combined hyperlipidemia (fchl). to further understand the in vivo turnover of apolipoprotein b-100 of very low density lipoprotein subfractions (vldl 1 , svedberg units (s f ) 60-400 and vldl 2 , s f 20-60) kinetic studies were performed in subjects with t2d, igt, fchl, and healthy controls using a tracer of either l-[ring-13 c 6 ]-phenylalanine or l-[5,5,5-2 h 3 ]leucine. these studies showed direct hepatic vldl 1 apob-100 secretion to be increased in patients with t2d and igt when compared with controls. in contrast, patients with fchl showed a discrete increase in hepatic vldl 2 apob-100 secretion. in all patients vldl catabolism is not essentially impaired. vldl 1 apob-100 secretion is associated with plasma insulin and free fatty acid (ffa) concentrations, resp., whereas vldl 2 apob-100 secretion is correlated with plasma mevalonate and lathosterol levels. in conclusion, vldl overproduction is supposed to be completely responsible for higher triglyceride (tg) levels found in patients with t2d, igt, and fchl. vldl 1 overproduction seems to be regulated by tg and ffa substrate and appears to be an indicator of decreased insulin sensitivity. in contrast, vldl 2 overproduction is more likely to be regulated by the availability of cholesterol substrate. these data give further in vivo evidence that vldl 1 and vldl 2 secretion is regulated independently. arabidopsis resulted in enhanced production of cysteine and glutathione graduate school of pharmaceutical sciences, chiba university, chiba, japan serine acetyltransferase (satase) catalyzes the formation of o-acetyl-l-serine (oas) which is the key intermediate of cysteine biosynthesis. oas is not only a dominant limiting factor but recently suggested as a possible signal molecule for gene expression in cysteine biosynthesis. in has been shown that the activity of cytosolic satase from watermelon was feedback inhibited by l-cysteine. to enhance the ability of cysteine biosynthesis in plants and to reveal the role of oas in the regulation of sulfur assimilation, we made the point-mutated watermelon satase gene (satg277c) whose product was not inhibited by cysteine, and introduced satg227c into arabidopsis. the contents of oas, cysteine, and glutathione in transgenic arabidopsis were increased significantly as compared to the wild-type arabidopsis. we are currently dealing with the expression analysis of sulfur-related genes in transgenic arabidopsis accumulating oas due to the overexpression of satase. certain amino acids as source of specific branched chain fatty acids in fish sauce manufacture n. g. sanceda 1 , e. suzuki 2 , and t. kurata 1 1 institute of environmental science for human life, and 2 department of human biological studies, ochanomizu university, tokyo, japan the source of some branched volatile fatty acids (vfa) during the fermentation process in the manufacture of fish sauce was investigated. we previously reported that straight chain volatile acids seemed to have been derived from fish fats but unlikely for branched fatty acids which was believed to be derived from other sources. to clarify the source of branched volatile acids, specific amino acids, alanine, leucine, iso-leucine and valine were used in this study. these amino acids were first mixed with salt and added to fish. the fish mixtures were then aerobically and anaerobically incubated for one and a half months. results showed that addition of valine significantly increased the production of iso-butyric and iso-hexanoic acids and leucine increased that of iso-valeric in the aerobically fermented fish mixtures. a similar tendency was observed in the anaerobically fermented fish mixture except that an increase in the amount of iso-hexanoic acid was observed in the leucine added mixture, which was not observed in the aerobically fermented one. it seemed that specific branched volatile fatty acids were derived from certain amino acids. glutathione (gsh) is an important component of the cellular defense mechanisms that protect cells from oxidative injury. in the retina, the glial (müller) cells have been shown to synthesize and transport gsh, and thus are likely to be involved in regulating gsh levels. in the present study, we have characterized gsh transport system in a müller cell line using 35 s-gsh uptake. the results showed that gsh was taken up in a na ϩ -and concentration-dependent manner with a k m of 0.31 mm. moreover, cellular gsh had no effect on the rate of gsh uptake. in related studies, we found that oxidative stress induced the expression of γ-glutamylcysteine synthetase (gcs) subunits, and that gcs mrna levels were correlated with the degree of gsh depletion. because organic anion transporters (oatps) have been implicated in glutathione cotransport, we examined expression of oatp members using rt-pcr. we found that the müller cell line expressed transcripts for oatp1, oatp2 and oatp3. these studies indicate that the müller cell plays important role in gsh homeostasis in the retina. in the active site of human porphobilinogen synthase (ec 4.2.1.24, pbgs), two zinc ions are coordinated by cys 122 , cys 123 and cys 132 , and his 131 and cys 223 , respectively. the fomer zinc ion, closer to catalytic site lys 252 , plays an important role in catalysis. on the other hand, a role of the latter (distal) one has not been clarified. interestingly, in human hep3b cell, his 131 was replaced with arg (h131r). to elucidate the role of his 131 in catalysis, the kinetic properties of wild type and h131r mutant enzymes were studied. these cdnas were cloned by rt-pcr with total rna from human peripheral lymphocyte and hep3b cell, respectively. each cdna encoding pbgs with 3ј non-coding region was inserted into pet-22b(ϩ) vector and then the constract was transformed into e. coli strain bl21(de3). the cells were cultured in lb medium containing 50 mg/ml ampicillin and 10 µm zn ion for 3 h at 37°c. after addition of 1 mm isopropyl--d(ϫ)-thiogalactopyranoside, cells were further cultured for 24 h at 20°c. the highly purified pbgss were obtained by ultora centrifugion, fractionation with ammonium sulfate and column chromatographies with deaecellulose, hydroxylapatite and superdex 200, serially. we are now investigating molecular properties of these pbgss. agriculture and agri-food canada, lacombe research centre, lacombe, alberta, canada handling and management procedures such as capture and restraint can be significant stressors for recently domesticated animals such as elk (cervidae elaphus). the objective of the current study was to investigate the use of pre capture nutritional therapy in attenuating hpa response and improving animal welfare. fourty eight adult male elk stags ranging in age from 2-4 years and raised on pasture were used in the study with 23 as control and 25 as nutritionally treated. twenty four hours prior to capture the elk were offered either 1 kg of a cereal grain based dietary supplement or 1 kg of a cereal grain based nutritional therapy product containing specified amino acids (usa patent # 5505968). the amino acid content of the nutritional therapy product was minimally 0.5 g per 500 kg animal weight of ala, lys, phen, meth, thre, isoleu, val and tryp plus 15 g per 500 kg weight of leu and 40 g/500 kg weight of glut. the animals were subsequently captured and held in appropriate facilities designed to handle elk. saliva samples were collected on all animals immediately following capture and salivary cortisol was monitored by ria. animals offered the nutritional therapy product containing the amino acid mixture displayed lower cortisol levels (11.8 nmol/l) compared to the untreated controls (14.9 nmol/l; p ͻ 0.05). the data suggest that amino acid therapy can be used to attenuate hpa response to a stressor in captured elk. department of bioengeneering and technology, delhi, new delhi, india resistance to analogues of methionine by corynebacterium lilium results in the partial de-repression of methionine biosynthetic enzymes. the levels of enzymes involved in methionine biosynthesis also increased step-wise by successive endowing the resistant markers, resulting in the overproduction of methionine. moreover, the repressibilities of the enzymes were also reduced by the addition of methionine analogue resistance. analogue resistant mutants were developed by uv induced mutagenesis of corynebacterium lilium (wild type) strain. the single analogue (norleucine) resistant mutant c. lilium nl-87 produced 372 µg/ml methionine in shake flasks with methionine yield at 0.068 g methionine/g glucose and specific methionine production at 0.237 mg/g dcw, while double analogue (norleucine and triazole) resistant mutant c. lilium nt-33 produced 521 µg/ml methionine. a triple analogue (norleucine, triazole and ethionine) resistant mutant c. lilium nte-99 produced 1.848 g/l methionine. the methionine yield was 0.248 g methionine/g glucose and its specific productivity was 1.04 g methionine/g dcw. clinical biochemistry, laboratory 22, luxemburg, grand duchy of luxemburg blood plasma glucose level was compared on fast and 60 minutes after oral administration of 1200 mg of acetylcysteine. in the group of 49 healthy persons the plasma glucose level feel by 7.6% over the 60 minute period. in the 30 diabetics on the contrary, the plasma glucose level observed 60 minutes after administration of acetylcysteine was 11.8% higher than in blood plasma taken on fast. similar tests were carried out "in vitro" to interpret these different results. the control group consisted of 1 ml of distilled water ϩ0.2 ml 10% glucose ϩ0.2 ml god pad (boringer mannheim gmbh). in the acetylcysteine group the distilled water was replaced by 1 ml 0.01% solution of acetylcysteine. in the glucagon group the distilled water was replaced by 0.01% solution of glucagen hypokit novo nordisk. spectrometric determination was carried out after 60 minutes of incubation. a 27% diminution of glucose was observed in the acetylcysteine group in comparison with the control group. a 32.2% increase in glucose was observed in the glucagon group in relation to the controls. the results with healthy persons and the tests "in vitro" indicate that acetylcysteine lowers the level of glucose. but it elevates the level of glucose in the blood plasma of diabetics. it may be presumed that acetylcysteine modifies the insulinglucagon balance in favour of glucagon. the objective of this study was to fortify yogurt with three oilseed protein hydrolysates prepared from soybean (glycine max), sesame (sesanum indicum) and rice bran (oryza sativa) flours. hydrolysis was carried with two enzymes one of plant origin (papain) and the other of microbial origin (alcalase). a yogurt fortification experiment was then carried using the previous hydrolysates. the hydrolysates were added to yoghurt at 5, 10 and 15% levels of fortification and the fortified yoghurt was analyzed fresh, and after 7 and 15 days of consuming period. fortified yogurt was chemically examined for fermentation activity (ph values, acidity and proteolysis) as well as its organoleptic properties. results of this experiment indicate that the addition of soybean hydrolysates with papain (8.9 units/g) for 5 minutes (tb) and rice bran hydrolysates with alcalase (27.6 units/g) for 5 minutes (te) to yoghurt can ex-ceed 5-10%, while fortification with sesame hydrolysed with papain (8.9 units/g) for 30 minutes (td) and soybean hydrolysed with papain (8.9 units/g) for 30 minutes (tc) can not reach up to 15%. it is well known that dna is fragile to reactive oxygen intermediates (rois) damage. evidences that dna fragmentation and apoptosis occur in cardiomyopathies, in the failing heart and in cultured cells under hyperbaric oxygen (hbo) stress, demonstrated that oxygen free radicals also play a critical role in heart failure. as a consequence, myocardial cell survival depends on response to oxidative stress. experimental data obtained in vitro suggested that polyamines, by acting as rois scavengers, play a role in prevention of endonucleasemediated dna fragmentation and inhibition of alkylating agents-mediated damage, potentially exerting a protective role against rois damage. thus we studied polyamine metabolism and superoxide dismutase (sod) expression in an in vivo model of heart oxidative stress, such as rats subjected to hbo. four experimental groups were used: 1) controls; 2) rats subjected to hbo for 15 min once and immediately sacrificed; 3) rats treated as group 2 but for 3 consecutive days and immediately sacrificed; 4) rats treated as group 3 but sacrificed 24 h later (recovery). northern blot analyses showed that odc mrna accumulation increased immediately (paralleled by activity) in groups 2-4, while ssat mrna decreased remarkably, thus leading to higher polyamine concentration in rois-stressed hearts. contrariwise, sod mrna level decreased rapidly in groups 2-4. this suggests that hbo-induced compensatory mechanism in rat heart is based on specific and rapid boosting of polyamine concentration, caused by coordinate induction of biosynthesis and inhibition of catabolism, and not of enzymes known to metabolise rois such as sod. amino acids oxidation was greater in tumor-bearing rats muscle. leucine is an important ketogenic amino acid that proves energy to the skeletal muscle. leucine supplemented diet was used to analyze the effects produced by walker 256 growing in pregnant rats which were distributed into six groups. three groups received normal diet (18% protein): control (c), tumor-bearing (w), pair-fed rats (cp). three groups were fed with diet supplemented with 3% leucine (15% protein plus 3% leucine): pregnant fed with leucine (l), tumor-bearing with leucine (wl) and pair-fed with leucine (lp). after 21 days, the animals were submitted to intestinal perfusion to measure leucine, methionine and glucose absorption. leucine absorption increased in w and wl groups. glucose absorption reduced in tumor-bearing. in pregnancy with cancer, metabolic changes provided both reduced fetal and tumor development. tumor-bearing rats showed increase in methionine and leucine absorption, probably diverting this nutrients to tumor cells. glucose absorption reduced in w and wl. leucine supplemented diet group promoted high leucine absorption which could be used by neoplasic cells, and mainly by fetus and host. probably, the transamination of the branch long chain amino acid provided energy substract for the skeletal muscle, keeping the nitrogen offered to host carcass. ( undernutrition cause several changes as body weight loss, in biochemical parameters, even microscopic alteration in absorptive epithelium. this means the nutrients absorption process has been harmfully and consequently increase the damages caused by malnourished. knowing leucine is used as a ketonic and oxidative amino acid our main propose was to recovery the malnourished young rats with normal (rc) and leucine supplemented diet (rl, 3% of leucine) for 60 days. it was measured body, liver, and muscle weight, intestinal absorption of glucose, methionine and leucine, and body chemical composition. the body weight gain in rc and rl was higher than control group, suggesting that nutritional replacement for these groups could provided nutrients to support the body weight recovery, reaching as the same weight as the control. methionine and glucose absorption was reduced in malnourished group, but it was recovered (glucose, methionine and leucine) after nutritional replacement. leucine supplemented diet promoted a good recovery of carcass collagen nitrogen, keeping the carcass structural nitrogen. further studies are necessary to investigate this mechanism. [financial support: fapesp ( we diagnosed the very rare autosomal recessive disorder hyperprolinaemia type ii (deficiency of ∆ 1 -pyrroline-5carboxylate dehydrogenase, ec 1.5.1.12) in a girl aged 20 months presenting with seizures and encephalopathy. l-∆ 1pyrroline-5-carboxylic acid accumulates in this disorder and there is a 10-15-fold increase in plasma proline. surprisingly, she also had vitamin b 6 deficiency. this was an unrecognised association, which was not explained by her diet or medications. we hypothesised that pyridoxal phosphate (vitamin b 6 coenzyme) was de-activated by l-∆ 1 -pyrroline-5-carboxylic acid. with high resolution 1 h nuclear magnetic resonance spectroscopy and mass spectrometry, we have shown that these two compounds react at ph 7.4 and 37°c in vitro to form three novel adducts, which we characterised. they are products of a claisen condensation (or knoevenagel type of reaction) of the activated c4 carbon of the pyrroline ring with the aldehyde carbon of pyridoxal phosphate. if this previously unreported interaction occurs in vivo, pyrroline-5-carboxylic acid is a unique endogenous vitamin antagonist. preliminary observations show that pyrroline-5-carboxylic acid also condenses with other biologically important aldehydes and ketones. some of these reactions may contribute to the brain disturbances in hyperprolinaemia type ii. we have already identified adducts with acetoacetic acid in urine from our child, which is evidence that condensation can occur in vivo. the kidneys are characterized by a high activity of γglutamyl transpeptidase (γ-gt), as well as by a high cysteine level. the present paper was aimed to obtain information on how the activity of γ-gt and the levels of non-protein sulfhydryl compounds (npsh) changed with age in rat kidneys. simultaneously, protein-bound cysteine (pb-cys) and sulfane sulfur compounds were estimated. the kidneys were from following rats groups: young (3-month-old), middle-aged (19month-old) and old (31-month-old). the obtained results showed that the activity of γgt and npsh levels in the kidneys fell with age. at the same time, a significant increase in the level of protein-bound cysteine was observed. on the other hand, the content of sulfane sulfur compounds was elevated in the group of the oldest animals. these findings indicate that -due to disturbances in the γ-glutamyl cycle -the capacity for extracellular glutathione degradation and, in consequence, the availability of cysteine for intracellular gsh biosynthesis may be impaired. the increased pb-cys level indicates potentiation of the thiolation reaction, i.e. development of protein-mixed disulphides, cysteine, sulfane sulfur compounds, oxygen reactive species. national research centre, dokki, cairo, egypt in the past few years, many attempts have been made to prepare a synthetic insulin. the biological activity of insulin is known to be closely related to the c-terminal octapeptide fragment of its b-chain. this does not necessarily mean, however, that each of the amino acid residues of the octapeptide fragment is essential for its activity. it was found that b 23 gly and b 24 phe were present in all insulins so far obtained from various animal species indicating the significance of these two residues. it would therefore seem desirable to study the effect of each of these two amino acid residues or both on biological activity of the octapeptiede fragment of the b-chain. weitzel et al. found that the substitution of arginine b 22 with another amino acid resulted in a very large decrease in biological activity, which indicates that it participates in the action of insulin. also it was found that the aromatic amino acid residues (b 24 -b 25 ) participate in the action of insulin. a heptapeptide arg-phe-tyr-thr-pro-lys-ala-och 3 , corresponding to (b 22 -b 30 ) insulin des gly 23 -phe 24 , and an octapeptide arg-phe-phe-tyr-thr-pro-lys-ala-och 3 , des gly 23 were synthesized using the solid phase method. the c-termenal ends of both peptide were converted to methyl ester by transesterification cleavage from the resin. the side chain protecting groups were removed by hf. manual counter current distribution method was used for purification of the free peptides. the way to solve the evaluation of tyrosine containing peptide was studied. the free methyl ester peptides were administrated for insulin-like activity test by glucose metabolism in the rat fat cells technique in vitro. nitric oxide synthase inhibitors influence dynorphin immunoreactivity in the rat brain following hyperthermia p. alm 1 and h. s. sharma 2 1 department of pathology, university hospital, lund university, lund, and 2 laboratory of neuroanatomy, department of medical cell biology, biomedical centre, uppsala university, uppsala, sweden nitric oxide (no) is a free radical gas that influences neuronal communication in the central nervous system (cns). recent reports suggest that no can influence dynorphin neurotransmission in the normal brain as well as in several pathological states. previous reports from our laboratory show that the enzyme nitric oxide synthase (nos) responsible for no formation is upregulated in several brain regions following hyperthermia. the present investigation was carried out to find, whether hyperthermia can influence dynorphin immunoreactivity in the brain, and if so, whether inhibition of nitric oxide synthesis will alter its distribution in heat stressed rats. rats subjected to hyperthermia at 38°c for 4 h in a biological oxygen demand incubator (bod) resulted in marked redistribution of dynorphin immunoreactivity in several brain regions e.g., cerebral cortex, hippocampus, cerebellum and brain stem. pretreatment with two potent nos inhibitors, l-name (50 mg/kg, i.p.) and l-nmma (30 mg/kg, i.p.) 30 min before heat stress significantly altered the dynorphin immunoreactivity in the brain. these drugs alone however, did not influence the peptide expression in normal rats. the results suggest that (i) hyperthermia has the capacity to influence dynorphin immunoreactivity in the brain, and (ii) inhibition of nitric oxide synthase considerably influences the dynorphin immunoreaction in hyperthermia, not reported earlier. the functional changes induced by uncompetitive and competitive nmda antagonists, memantine, amantadine and mk-801, and cgp 40116, respectively, were studied in both saline-pretreated and mptp-pretreated c57 bl/6 mice. the nmda antagonists were administered acutely by themselves or in combinations of either: nmda antagonist plus subthreshold l-dopa dose or nmda antagonist plus suprathreshold l-dopa dose, to either the mptp-pretreated or the salinetreated mice. activity-enhancing or functional restorative effects of the nmda antagonists were variable with memantine and mk-801 distinguished from amantadine and cgp 40116. in the study of long-term effect of nmda antagonists mk-801 was administered postnatally and spontaneous motor behaviour and motor activity in response to several pharmacological interventions was assessed. marked alterations associated possible with apoptotic penchance are discussed. t. archer 1 and a. fredriksson 2 1 department of psychology, university of göteborg, and 2 department of psychiatry, university of uppsala, ulleråkers hospital, uppsala, sweden synergistic antiparkinsonian actions of different classes of putative therapeutic agents co-administered with a subthreshold dose of l-dopa (5 mg/kg) in drug-naive mptp-treated mice as well as the restorative actions of those compounds in suprathreshold l-dopa-tolerant mptp-treated mice subjected to "wearing-off" of l-dopa efficacy were assessed in a series of experiments. the classes of compounds studied included the noncompetitive nmda antagonists, memantine, amantadine and mk-801, the anticonvulsive and putative anticonvulsive agents, lamotrigine, fce 26743, phenytoin, the monoamine oxidase inhibitors, l-deprenyl, amiflamine, α-ethyltryptamine, clorgyline and phenelzine, and the α 2 -adrenoceptor agonists, clonidine and guanfacine. in this final case, the restorative effects of clonidine and guanfacine were antagonised by the α 2 -adrenoceptor antagonist, yohimbine, but not the α 1adrenoceptor antagonist, prazosin. within each class of potentially therapeutic agents a differential restorative efficacy was obtained, but the combination of different doses of apomorphine with clondine failed to restore motor activity. in vivo proton mr-spectroscopy of the human brain: assessment of n-acetylaspartate (naa) reduction as a marker for neurodegeneration w. block 1 , f. träber 1 , s. flacke 1 , f. jessen 2 , ch. pohl 3 , and h. h. schild 1 1 department of radiology, 2 department of psychiatry, and 3 department of neurology, university of bonn, germany proton magnetic resonance spectroscopy ( 1 h-mrs) is a well accepted non-invasive method to investigate changes in brain metabolite composition in different types of cerebral disease. we performed proton spectroscopy in patients with dementia of the alzheimer's type (ad) and in patients with motor neuron disease (mnd) with the aim to detect a specific metabolic pattern for each of these two neurodegenerative disorders. overall, more than 150 spectroscopic data sets of patients with mnd and more than 100 data sets of ad patients were acquired within the last 5 years. in the mnd group we found a significant reduction of naa/tcr metabolite ratios in the central region, which correlates with the disease severity and the clinical lateralisation of neurological symptoms and increases in the time course of the disease. in ad patients a similar reduction in relative naa contents was observed in the medial temporal lobe. the observed regional metabolic alterations correlate well with the characteristic neurological symptoms in ad (dementia) and mnd (muscular palsy) and seem to follow the disease process over time. since naa is exclusively expressed in neurons as shown by immunohistochemical studies, reduced naa levels suggest neuronal loss or dysfunction in the observed regions. center for molecular imaging research, massachusetts general hospital, boston, massachusetts, u.s.a. non-invasive measurement of hemodynamic parameters and imaging neovasculature architecture during angiogenesis is highly important in determining tumor prognosis and in assessing treatment efficacy. we suggested a technique to map the tumor vascular (vvf) and interstitial volume fraction (ivf) noninvasively in vivo. a poly-l-lysine based macromolecular probe (mpeg-pl-gddtpa) with extended circulation in the bloodstream designed to shield chelated paramagnetic lantanide with poly(ethylene glycol) chains. we hypothesized that a magnetic resonance signal after intravenous administration of a vascular paramagnetic probe can be maximized so the signal change after administration of a second comound (gddtpa) reflects the ivf but not the vvf. the method and its assumptions were verified in animal models of cancer. tumoral vvf and ivf values were consistent with histology data and literature values. imaging showed heterogeneity of both parameters at submillimeter pixel resolution. this technique was used for characterizing differential angiogenesis in human mammary adenocarcinoma lines as well as for imaging anti-angiogenic drug effects. anti-angiogenesis was induced using synthetic d-reverse peptides derived from thrombospondin-1. this study showed that peptide treatment results in slower brain tumor growth due to inhibition of de novo blood vessel formation and synergistic anti-proliferative effect on tumor cells. in conclusion, in vivo mr imaging can be used for non-invasive treatment assessment of novel antiangiogenic drugs. wallenberg neuroscience centre, lund university, lund, sweden we have recently found that 6-hydroxydopamine lesioned rats gradually develop dyskinetic-and dystonic-like movements upon repeated administration of a therapeutic dose of l-dopa. such movements simulate the time course of peak-dose dyskinesia in parkinson's disease. in this rat model, the severity of l-dopa-induced dyskinesia is strongly correlated with an upregulated expression of the prodynorphin gene in striatal neurons. using antisense technology and gel-shift assay analyses, we have addressed the role of transcription factors which may mediate this response. we have found that the camp response-element binding protein (creb) is essential in maintaining a basal expression of prodynorphin mrna in the intact striatum, but it is not required for l-dopa to induce the prodynorphin gene in dopamine-denervated striatal neurons. we have thus addressed the role of fos-and jun family tran-scription factors, and found very high levels of fosb-and jundlike proteins in the striata of dyskinetic animals. these proteins could bind to both ap1 and cre sites in the prodynorphin promoter. moreover, intrastriatal fosb knockdown could inhibit both the upregulation of prodynorphin gene expression and the development of dyskinesias under chronic l-dopa treatment. we propose that dimers of fosb-and jund-like proteins mediate abnormal changes in striatal gene expression which are linked to the development of l-dopa-induced dyskinesia. department of pharmacology, grünenthal gmbh r&d, aachen, germany glutamate plays important roles in both normal and pathophysiological nocieception. upon physiological conditions, glutamate release from primary afferents in the spinal cord activates largely ampa receptors. as those are ubiquitously involved in fast transmission in the cns, ampa antagonists have a broad side-effect profile. prolonged activation of nociceptors by tissue damage, inflammation or nerve injury evokes a long-lasting release of glutamate and neuropeptides, activating nmda receptors in the spinal cord. this mechanism appears to play a key role in pain chronification. the nmda receptor is, therefore, an important target for chronic pain treatment. both animal and human studies confirm the efficacy of nmda antagonists in chronic pain, however, clinically available compounds are weak or have unacceptable side-effects. glycine b antagonists and compounds selectively blocking nr2b-containing receptors appear to be safer, the reasons for this remain unclear. central side-effects could potentially be avoided by using nmda antagonists with restricted central access. peripheral nmda receptors (as well as some other subtypes of glurs) could be activated by glutamate released from the site of injury, thus contributing to peripheral hyperexcitability. some other subtypes of glurs can also contribute to peripheral sensitisation. of ionotropic glurs, kainate receptors appear important in inflammatory and neuropathic pain. they can be activated by high intensity stimulation of nociceptive afferents, and may act as autoreceptors controlling release of glutamate. group i metabotropic glurs are also present on primary afferents and on second order neurones in the spinal cord, and may play a similar role. antagonists of these subtypes of glurs are active in some models of chronic pain. specific upregulation of group ii metabotropic glurs in some pain-relevant structures could reflect a possible adaptive role of these inhibitory receptors under chronic pain conditions; their selective agonists also have a potential for the treatment of chronic pain. we have performed a series of studies of the distribution and function of mglur subtypes in the basal ganglia that suggest that members of this receptor family could serve as targets for novel therapeutic agents that would be effective in treatment of pd. for instance, two group ii mglurs (mglur4 and mglur7) are localized on presynaptic terminals of striatal neurons in the globus pallidus where they could reduce gaba release. furthermore, activation of group i mglurs results in a depolarization and increased cell firing of neurons in the subthalamic nucleus (stn) and projection neurons of the substantia nigra pars reticulata (snpr). interestingly, this effect is mediated by mglur1 in snpr projection neurons and mglur5 in stn neurons. finally, activation of group ii mglurs results in inhibition of glutamate release from stn terminals in the snpr. furthermore, selective agonists of group ii mglurs inhibit haloperidol-induced catalepsy in rats, suggesting an antiparkinsonian effect of these compounds. the rich distribution and diverse physiological roles of mglurs in basal ganglia raises the possibility that these receptors may provide targets for novel therapeutic agents that could be used for treatment of pd and related disorders. a. cupello 1 , m. parodi 2 , and m. balestrino 2 1 centro di neurofisiologia cerebrale, cnr, genova and 2 dipartimento di scienze neurologiche, university of genova, italy in vitro rat hippocampal slices are commonly used to study the effects of hypoxia in the central nervous system, because they allow to differentiate the effects of hypoxia in the brain from that of systemic (e.g., respiratory and cardiac) failure that may accompany hypoxia. we used electrophysiology to monitor and evaluate the damage caused by transient hypoxia to the nervous tissue. a few minutes after oxygen deprivation brain tissue suddenly depolarizes. this event, which is termed ìanoxic depolarizationî is accompanied by dramatic metabolic changes: transmembrane ionic gradients disappear (na ϩ enters, k ϩ exits the neurons), neurons swell, there is intra-and extra-cellular acidosis. this event is caused by functional inactivation of (na ϩ / k ϩ )atpase caused by decreased atp content, as it is suggested by the fact that it is mimicked by ouabain treatment. one of us has contributed to show that if this event is not promptly reversed by reoxygenation it causes irreversible damage, mainly by determining a massive entry of ca 2ϩ into neurons. pretreatment of tissue with creatine (1 mm or more) both increases neuronal energy store by increasing neuronal phosphocreatine and protects brain tissue from irreversible damage. in vivo increase in phosphocreatine has been shown using lower (0.5 mm) creatine concentration, injected directly into the lateral ventricle. a different type of hypoxia-induced damage is observed when hypoxia is of shorter duration. in this case upon reoxygenation one does not observe disappearance of evoked potentials but their increase. this phenomenon, originally described as ìpost-hypoxic hyperexcitabilityî has been later called ìanoxic long-term potentiation (ltp)î. we showed that this event can be prevented by inactivating the nuclear protein s-100. while this damage is milder than that induced by anoxic depolarization, it may explain stroke-induced epileptic fits. we are currently investigating what role, if any, pretreatment with creatine may have in preventing also this type of damage. cytoskeleton is subject to continuous modification to yield changes in cell shape and function of plasmamembrane proteins linked to the cytoskeleton. gelsolin (gsn) depolymerizes filamentous actin and thus causes dynamic uncoupling of membrane ion channels. we have studied alteration of neuronal ca 2ϩ influx by the absence of gsn and its pathophysiological consequences during cerebral ischemia. cytosolic ca 2ϩ concentrations were determined ratiometrically in synaptosomes preloaded with fura-2am. glutamate release from synaptosomes superfused with krebs' buffer was measured by hplc. transient focal cerebral ischemia was induced by 2 h occlusion of the middle cerebral artery (mca). in gsn deficient mouse brain cortical synaptosomes [ca 2ϩ ] i increase in response to k ϩ (30 mm) depolarization was 42% higher than in wild-type. ω-agatoxin iva 0.2 µm decreased ca 2ϩ -influx in neocortical wild-type synaptosomes by 53%, and abolished differences between gsnϩ/ϩ and ϫ/ϫ genotype. k ϩinduced release of glutamate in neocortical synaptosomes was 78% higher and lesion size after mca occlusion was 45% higher than in wild-type. it is concluded that presynaptic ca 2ϩ influx is increased in gsn deficient nerve terminals which, together with subsequently increased glutamate release, increases neuronal vulnerability. in vivo assessment of tissue alteration in cerebrovascular and neurodegenerative diseases s. flacke, w. block, f. träber, p. mürtz, h. urbach, and h. schild the combined used of perfusion imaging (pi) and molecular diffusion imaging (dwi) are opening a new window into the processes that occur during the first hours of ischemia. dwi detects early changes of proton diffusion associated with cytotoxic edema. pi has the potential to characterize the degree of regional hypoperfusion. mismatches between dwi and pi, i.e. hypoperfused areas with normal adc are considered potentially salvageable. we present results of 11 patients with an angiographically defined thrombembolus in the middle cerebral artery and a spontaneous stroke evolution. whereas the infarct core was clearly visible on both dwi and pi, tissue at risk of infarction could only be detected by an increased blood volume and transit time. however only in a subgroup of patients (n ϭ 3) these areas were incorporated into the final infarct. in these patients perfusion parameter of tissue at risk of infarction were more pronouncedly altered than in those where the tissue at risk was spared from infarction (ratios of tissue at risk vs normal (rcbv 2.17 ϯ 0.59, mtt 1.67 ϯ 0.22, ttp 1.32 ϯ 0.11, p ͻ .05). these human data show that a detailed analysis of diffusion/ perfusion mismatches allow the identification of tissue at risk of damage. glucose deprivation enhances the sensitivity of cerebellar granule cells to die by excitotoxicity. we have previously reported that neither 70 min of glucose deprivation, a treatment that depletes cell energy resources, nor exposure to 20 µm glutamate (glu) for 30 min, induce significant cell death in cerebellar granule cell cultures, 24 h after treatment. in contrast, the combined treatment with 20 µm glu and glucose deprivation induces both cell death and choline (cho) release. we investigated whether the neurotoxic effect of this treatment is related with inhibition of phosphatidylcholine (pc) synthesis. we found that exposure to 20 µm glu alone for 30 min, glucose deprivation for 70 min, and the combination of both treatments inhibited pc synthesis when measured at the end of treatment by 71%, 92% and 91%, respectively. furthermore, we found that exposure to either 20 µm glu, glucose deprivation or 20 µm glu ϩ glucose deprivation decreased incorporation of [ 3 h]cho into phosphocholine and increased the intracellular content of free [ 3 h]cho, indicating that all these treatments inhibit the synthesis of pc by inhibiting choline kinase activity. since only the combined treatment with 20 µm glu plus glucose deprivation evoked cho release and excitotoxic cell death, the present results indicate that other factors in addition to inhibition of pc synthesis are required to induce cho release and excitotoxic cell death in cerebellar granule cells. (supported by cicyt, saf98-0063.) the role of striatal metabotropic glutamate receptors in degeneration of dopamine neurons k. goĺembiowska, j. konieczny, k. ossowska, and institute of pharmacology, polish academy of sciences, kraków, poland the present study was undertaken to characterize the effect of blockade of the mglu 5 receptor subtype by 2-methyl-6-phenylethynylpyridine (mpep), as well as the effect of stimulation of the mglu 2/3 receptor by (ϫ)-2-oxa-4aminobicyclo[3.1.0]hexane-4,6-dicarboxylic acid (ly379268) on spontaneous and stimulated dopamine (da) release in rat striatum using an in vivo microdialysis. mpep (100-500 µm), perfused through a microdialysis probe affected neither the basal nor the veratridine (100 µm)-stimulated striatal da release. however, mpep given intraperitoneally (5 mg/kg) diminished either the basal or the veratridine-evoked da release. ly379268 (100-250 µm) administered locally also inhibited the veratridine-evoked da release in rat striatum. antagonists of mglur-i and agonists of mglur-ii have been shown to have neuroprotective properties in several models of neurotoxicity in animals. we have approached this issue using a selective mglu 5 antagonist in an animal model of neurotoxicity induced by methamphetamine. in our preliminary experiments, methamphetamine (5 ϫ 10 mg/kg sc every two hours) decreased the tissue content of striatal da and its metabolites dopac and hva.mpep (5 ϫ 5 mg/kg ip) given before every methamphetamine injection reversed its action. the effect exerted by the mglu 5 antagonist mpep seem to be mediated by sites located outside the striatum due to relieving da neurons of the facilitatory influence of glutamate. in turn, the attenuation of da release from nigrostriatal terminals by ly379269 may be a consequence of activation of striatal mglu 2/3 receptors. reversal of the methampetamine-induced da depletion suggests a potential for neuroprotective activity of mpep. o. golubnitschaja 1 , h. h. schild 1 , and j. flammer 2 1 department of radiology, university of bonn, germany 2 university eye clinic, basel, switzerland glaucoma remains a major eye illness with unknown etiology. although elevated intraocular pressure has been shown to be the major risk factor, there is a cohort of relatively young patients developing normal-tension glaucoma (ntg). assymptomatic ischemic events in brain have been shown to be often attributable to galucoma. perfusion of the retina and optic nerve head suffering from observed vasospastic dysfunction may be further reduced by changes in the intraocular pressure. ocular ischemia developed due to these blood flow deficits may play a major role in initiation of glaucoma. possibly secondary to ischemia the autoimmunogenic capacity is activated by ntg patients having an increased prevalence of systemic autoimmune diseases. therefore, the determination of potential molecular markers in blood lymphocytes could be useful for early diagnostics of ntg. our recent study using "gent hunting"-techniques showed indeed altered gene expression in lymphocytes of ntg patients. the demonstrated downregulation of xpgc gene expression which subsequently leads to the accumulation of damaged dna and an elevated p53 expression, together with the upregulation of a new abc-transporter seem to be specific for the pathogenesis of ntg. molecular imaging of ntg provides insights in mechanisms of disease initiation and allows the early diagnostics and preventive treatment. (supported by "bio-rad" and "amersham pharmacia aggregate cell cultures prepared from fetal rat telencephalon were used to study neuronal amino acid consumption during glucose restriction. to that end, both mixed (neuronglia) and neuron-enriched cultures were grown in chemically defined medium and tested at an advanced maturational stage. it was found that 6 h of exposure to reduced glucose (0.25 mm instead of 25 mm) caused significant increases in the consumption of several amino acids and the accumulation of ammonia. it also greatly changed the intracellular level of several amino acids in neurons, particularly of aspartate and glutamate. irreversible neuron-specific damage was observed one week after the insult. elevated glutamine media concentrations (4 mm instead of 0.25 mm) during glucose restriction further increased ammonia production and neuronal damage, although the overall rate of glutamine metabolism remained practically unchanged. taken together, our findings suggest that glucose deficiency caused (i) the dysfunction of crucial transamination pathways; (ii) a shift towards the oxidative deamination of glutamine and several other amino acids used by neurons as alternative energy substrates; and (iii) the accumulation of neurotoxic ammonia levels. institute for brain research, university of vienna, austria the racemic (d,l) mixture of the naturally occurring neutral aromatic amino acid 3,4-dihydroxy-l-phenylalanine (l-dopa) was first synthetized in 1911. in 1913, the natural levorotatory isomer was isolated from vicia faba beans and declared to be biologically inactive. however, in 1930 l-dopa was observed to lower the blood pressure in the rabbit, an effect opposite to the vasopressor effect of adrenaline. following the discovery, in 1938, of the enzyme l-dopa decarboxylase, ldopa's conversion in tissues (by decarboxylation) to dopamine (da), the first biologically active substance in the biosynthetic pathway of catecholamines, was demonstrated. subsequent pharmacological studies, done between 1942 and 1957, showed that the biological actions of l-dopa were, in principle, due to da formed from it in the body. in 1957, the central antireserpine effect of d,l-dopa was described in mice and confirmed in 1960 with l-dopa in humans. following the demonstration of da's occurrence in the brain in the years 1957/58, d,l-dopa was found (in rabbits) to restore brain da levels, reduced by reserpine. in 1960, the severe brain da deficit, confined to patients with parkinson's disease (pd) was reported and a year later l-dopa's superior anti-akinesia effect in patients with pd demonstrated. finally, in 1967 the high-dose oral l-dopa regimen was successfully introduced into clinical practise. in contrast to these supreme achievements, two related early studies remained, for different reasons, without consequence. despite some initial doubts about its mechanism of action, there is now convincing evidence for l-dopa therapy being a classic example of a central neurotransmitter replacement therapy, with the severe brain da deficit furnishing a rational basis for the amino acid's clinical use and high efficacy in patients suffering from pd. b. jakobsen 1 , a. tasker 2 , and j. zimmer 1 1 anatomy and neurobiology, sdu-odense university, odense, denmark 2 department of anatomy and physiology, university of prince edward island, canada the toxicity of domoic acid (dom) was studied in rat hippocampal slice cultures, prepared from 7-days old rats and grown on semipermeable membranes for 2-3 weeks before exposure. dom (0.1-100 µm) was added to the medium, alone or together with the glutamate receptor antagonists ns-102, nbqx or mk-801, for 48 hrs followed by 48 hrs in normal medium. neuronal degeneration was monitored and ec 50 values estimated by densitometric measurements of the cellular uptake of the propidium iodide (pi) at 24, 48, 72 and 96 hrs. the lowest ec 50 values, obtained at 72 hrs, were: ca1 (6 µm), dentate granule cells (dg) and ca3ab (10 µm),ca3c (12 µm). protective effects of 10 µm nbqx at 72 hrs were seen against 3 µm dom in dg, ca1 and ca3c and against 10 µm dom in ca1 and ca3c. 10 µm ns102 and mk801 only displayed protective effects together with nbqx. mk801 thus significantly increased the protective effect of 10 µm nbqx in ca1 against 10 µm dom in combination with 10 µm nbqx and 10 µm ns102. we can confirm that dom neurotoxicity primarily involves ampa/kainate receptors, but also nmda receptors at high concentrations (glutamate release). department of physiology/neuroscience, medical university of south carolina, charleston, south carolina, u.s.a. although dopamine has been most clearly tied to the development of addiction to drugs of abuse, recent studies indicate that once addiction has been established the expression of addictive behaviors, such as drug craving, is mediated more by long-term neuroadaptaions in glutamate transmission. data will be presented which supports and extends this hypothesis. repeated cocaine injections were given for one week and three weeks after the last drug injection a number of molecular, neurochemical and behavioral neuroadaptations were measured. it was found that in the nucleus accumbens there is a increase in the expression of genes encoding mglur2/3 and glur1, and a decrease in the expression of mglur5 and its accompanying scaffolding proteins homer1bc. this was accompanied by an increase in the capacity of mglur2/3 receptors to regulate presynaptic glutamate release and a blunting in the effects of stimulating mglur1/5 receptors. in addition, there is reduced activity in the cystine/glutamate exchanger 3 wks after repeated cocaine. as a result of these changes there is a decrease in the basal release of glutamate, and a relative increase in the releasibility of glutamate upon stimulation. by using the reinstatement model of drug seeking behavior, it was shown that glutamate transmission in the projection from the prelimbic cortex to the core of the nucleus accumbens was particularly affected by the cocaine-induced changes in gene expression. taken together, these findings support the use of glutamate autoreceptor agonists as possible therapeutic adjuvants in treating the cravings associated with addiction. dopamine (da), a catechol that autoxidizes to an oquinone, is implicated as an endogenous pro-toxin, however, the following studies suggest that da has dual neurodegenerative and neuroprotective roles. in rats treated as neonates with 6-hydroxydopamine (6-ohda; 134 :g icv), there was a 99% reduction in striatal tissue da content in adulthood, and a 3 to 5fold increase in spontaneous hydroxyl radical (ho*) formation (indirect salicylate trapping method: dihydroxybenzoic acid analysis). additionally, systemic l-dopa (60 mg/kg i.p.) suppressed ho* formation. however, when glutamate (50 mm) was added to an in vivo microdialysate, ho* formation was increased substantially more in the microdialysate from dainnervated striatum. these findings indicate that da innervation is inherently neuroprotective, but in the presence of a high level of an excitatory amino acid, da innervation predisposes to formation of reactive oxygen species. ongoing neuronal activity is likely to interact with and to determine the role of da as a neurotoxic or neuroprotective substance. (supported by ns 39272.) the glutamate hypothesis of schizophrenia along with the dopamine hypothesis was intensively discussed in the past. the last years however suggest more and more that neither a hypofunction of the glutamatergic system alone nor a hypofunction of the dopaminergic system alone is responsible for symptoms found in schizophrenia. the basal ganglia (bg) as the critical structures mediating symptoms of schizophrenia are innervated by dopaminergic fibers from the mesencephalon as well as by glutamatergic fibers from limbic structures; like prefrontal cortex, hippocampus, entorhinal cortex and amygdala. thus, limbic input is able to modulate information processing in each structure of the bg and by this way control dopaminergic functions through feedback mechanisms. dysfunction in limbic structrues may result in an imbalance of information processing via the bg and terminates in behavioral symptoms of schizophrenia. we showed in recent neurochemical studies in combination with behavioral analysis that a simple, generalized hypofunction of limbic glutamatergic input on bg nuclei is not the key mechanism inducing schizophrenic behavior. a dysfunction of a particular limbic structure or pathway seems to be responsible for an imbalanced information processing via the bg and imbalanced behavioral adaptation terminating in schizophrenic symptoms. [ there is a need to identify subtype-specific ligands for mglu receptors to elucidate the potential of these receptors for the treatment of nervous system disorders. to date, most mglur antagonists are amino acid-like compounds acting as competitive antagonists at the glutamate binding site located in the large extracellular n-terminal domain. we have investigated novel subtype-selective mglur5 antagonists which are structurally unrelated to competitive mglur ligands. using a series of chimeric receptors and point mutations we demonstrate that these antagonists interact with novel allosteric binding sites in the tm domain via a noncompetitive mechanism of action. recent studies in animal models implicate mglu 5 receptors as a potentially important therapeutic target particularly for the treatment of pain and anxiety. vascular endothelial growth factor (vegf) is a major mediator in angiogenesis and vascular permeability. in central nervous system (cns) vegf plays pivotal roles such e.g., inductor of endothelial cell proliferation, migration and inhibition of apoptosis, as well as mediator of blood brain barrier (bbb) breakdown and subsequently of brain edema formation. these ubiquitous epiphenomena are major complications in several cns pathologies, including head trauma and stroke. reduced tissue oxygen tension (hypoxia) and hypoglycaemia triggers vegf expression that occurs in ischemic regions around postraumatic or postinfarct necrosis. after brain injury, the expression of vegf is increased contributing to disruption of the bbb. vegf increases the permeability of bbb via the synthesis/release of nitric oxide and subsequent activation of soluble guanylate cyclase. the immunohistochemistry shows an increase of stained astrocytes around a cortical micronecrosis. vegf participates in the response of the cns to injury in a dose dependent way. immunostaining correlates with infarct volume and clinical disability. vegf-antagonists reduce ischemic brain edema and injury, involving vegf in pathogenesis and eventually in treatment of stroke and related disorders. this cytokine also exerts a neuroprotective effect mediated by its receptor flk-1. functions related to the inflammatory response, co-expression with proteins of the ecm and interaction with the two main receptors, flk-1 and flt-1, will be discussed. n-methyl-d-aspartate (nmda) receptors can mediate excitotoxic or neuroprotective responses. one of the molecular mechanisms responsible for nmda neuroprotection involves the release of brain-derived neurotrophic factor (bdnf) which in turn binds to and activates its cognate receptor trkb. bdnf levels in the neuronal culture medium increased 2-fold when cells were preincubated for three hours with nmda. at three hours, the increase in bdnf protein levels in the medium was accompanied by a concomitant increase in bdnf mrna. thus, nmda elicited two temporally distinct responses: an early release of bdnf protein followed by a later transcriptional activation of dbnf mrna and protein release. these results suggest that nmda activates the trkb receptor via a bdnf autocrine loop resulting in neuronal survival. in addition, extracellular regulated kinases (erk 1/2) were rapidly activated, which peaked within six hours of nmda treatment. erk 1/2 activation is completely blocked by mk-801 and partially blocked by k252a, suggesting the nmda and trkb receptors act in a coordinated fashion to activate erk 1/2. as an extension of this work, we discovered a single nucleotide polymorphism in the human nr1 gene that, when transfected into hek cells, alters the electrophysiological properties of the nmda receptor complex. possible consequences of this nmda receptor variant in signaling will be discussed. this overview summarizes our recent knowledge of the role that tyrosyl radical (tyro • ) can play in neurochemical systems of brain and thereby lead to neural disorders (pd, ad, als). these could involve the interactions of tyrosine and tyro • with reactive oxygen species (ros) and reactive nitrogen species (rns), via radical mechanisms and chain processes in the presence of o 2 and endogenous brain antioxidants. concentrations of tyro • , ros and rns can increase dramatically under conditions of generalized stress: oxidative, nitrative or reductive. this in turn can directly damage (by lipid peroxidation) or indirectly damage (by protein oxidation and/or nitration) cellular substructures which ultimately can lead to apoptotic neuronal cell death or autoschizis. enzymatically (classical peroxidase mechanisms) or non-enzymatically formed tyro • can react with no • and this reversible and intrinsic "combination" acts to "buffer' tyro • concentrations. the reaction of tyro • with superoxide (o 2 •ϫ ) is a scavenging reaction which proceeds rather by addition, not by electron transfer; and major resultant products are tyrosine hydroperoxides (tyrooh). however, the decay of tyro • can be also terminated by self-termination (dimerization) resulting in dityrosine (dt) formation. tyro • can catalyze ldl oxidation, although the precise mechanisms of this reaction in vivo remain unknown. nitration of tyrosine to 3-nitrotyrosine (3-nt) requires a one-electron oxidation as a primary step, with formation of tyro • , followed by addition of the nitrogen dioxide radical (no • 2 ). the promoting effect of carbon dioxide on peroxynitrite-mediated tyrosine nitration (via radical mechanisms) (tyro • /no • /o 2 •ϫ /no • 2 system) is due to the selective reactivity of the putative carbonate radical anion, as compared to that of the oxidizing hydroxyl radicals ( • oh). moreover, once formed, 3-nt may act to promote repetitive redox cycling; it may be reduced to the corresponding nitroanion radical, which is then oxidized by molecular o 2 to o 2 •ϫ and parent 3-nt. one-electron oxidation of 3-nt can result in catalytically active imminoxyl radical. dt formation can outcompete tyrosine nitration at lowsteady state concentrations of peroxynitrite. it is unquestionable that very high fluxes of no • and o 2 •ϫ are requisite intermediates of peroxynitrite, a tyrosine nitration agent formed via tyro • . evidence for the existence of generalized stress within neurons includes the presence of protein peroxides (tyrooh), dt, and 3-nt. the nitration/denitration processes can be pathologic, but these also may play: 1) a signal transduction role; 2) a role of "blocker" for radical-radical reactions (scavenging of no • , no • 2 and co 3 •ϫ by tyro • ); or 3) a role of delimiting factors for peroxynitrite formation. it is still unknown whether oxidation/nitration of tyrosine (as dopamine precursor or protein residue) via tyro • formation, is a footprint of generalized stress and neuronal disorders, an important part of o 2 •ϫ and no • metabolism, or just a part of integral processes for maintaining neuronal homeostasis. the complete answer of these questions should be the first priority task of our recent search, wherein the problem of increased free radical formation in the brain and/or the imbalance of ratios: ros/rns/tyro • may be all important in determining neural cell and tissue injuries under pathological conditions resulted from generalized stress. [acknowledgements. this work was supported in part by kbn ( more than 50% of patients with type 2 diabetes have coronary heart disease, related to silent ischemia, caused by an autonomic denervation of the heart in diabetic patients. oxidative damage to dna has been well documented in cardiac cells isolated from diabetic patients and rats with streptozotocin-induced diabetes mellitus (dm) . this dmmodel shows already seven days after onset of disease structural changes in vascular tissue typical for the development of atherosclerosis. this study evaluates possible molecular mechanisms for early events in the development of dm-induced cardiomyopathy. methods: using "expression array" we examined the activation of cardiac cell death in heart of dm-rats. ms-pcr was used to examine a differential dna methylation. results: an increased expression of genes encoding renin, angiotensinogen and p53 was detected in heart of dm-rats. substantial changes in the methylation status of the p53dependent p21 waf1/cip1 -gene and the cyclin d1-gene were detected in dm-rats. conclusions: the renin-angiotensin system is upregulated with diabetes, and this may contribute to the development of cardiomyopathy via oxidative damage and p53-dependent activation of cardiac cell death. this pathway includes de novo methylation of the p53-inducible p21 waf1/cip1 -gene encoding a protein which binds to and inhibits a broad range of cyclincyclin-dependent kinase complexes. (supported by "bio-rad" and "amersham pharmacia biotech") department of pharmaceutical biosciences, uppsala university, uppsala, sweden during the past decade studies have indicated that growth hormone (gh) may exert effects on the central nervous system (cns). for instance, gh replacement therapy was found to improve the psychological capabilities in adult gh deficient (ghd) patients. furthermore, beneficial effects of the hormone on certain functions, including memory, mental alertness, motivation and working capacity have been reported. likewise gh treatment of ghd children has been observed to produce significant improvement in many behavioural problems seen in these individuals. studies also indicated that gh therapy affects the cerebrospinal fluid (csf) levels of various hormones and neurotransmitters. further support that the cns is a target for gh emerges from observations indicating that the hormone may cross the blood-brain-barrier (bbb) and from studies confirming the presence of gh receptors in the brain. it was previously shown that specific binding sites for gh are present in discrete areas in the cns of both humans and rats. in peripheral tissues gh is shown to elicit its effects through a second mediator insulin-like growth factor 1 (igf-1). igf-1 is well recognized as a protective agent against neural injury in the cns. the neuroprotective effect of this peptide has a broad spectrum affecting many brain regions and acts through its antiapoptopic effect. the production of igf-1 is upregulated in areas of brain damage and the igf-1 system may be an important part of an endogenous neuroprotective system. in spinal cord injuries, however, the content of igf-1 is reduced. we recently observed a neuroprotective effect of topical application of igf-1 in animals subjected to spinal cord trauma. the observed effect may be mediated via a mechanism involving nitric oxide. in the same animal model we have very recently observed a neuroprotective effect of gh. recent reports suggest that the level of gh is drastically reduced in patients with spinal cord injury. in victims of spinal cord injury the secretion of gh and igf-1, as well, is known to be decreased. therefore, exogenous substitution of gh and igf-1 might be a promising approach in the future therapy of spinal cord injury victims. in fact, there is one report indicating that prolonged treatment with synthetic gh of spinal cord injured rats attenuates some of the neurological motor dysfunction seen in these animals 3 weeks following trauma. in our animal model we observed that topical application of rgh significantly reduced traumainduced disturbances in the fluid micro-environment. we also noted that gh was capable of attenuating the trauma-induced depression of spinal cord evoked potentials. the mechanism by which gh exerts it neuroprotective effects will be discussed. chronically administered levodopa in parkinson's disease (pd) treatment is ultimately associated with alterations in motor response. in 6-hydroxydopamine lesioned hemiparkinsonian rats, chronic twice-daily administration of levodopa progressively shortens duration of contralateral turning and augments the period of turning at or below 20% of peak turning rate. the pathogenesis of the response alterations involves in part sensitization of the corticostriatal glutamatergic synaptic activity. characteristic changes involving interactions between striatal kinase and phosphatase signaling now appear to contribute to sensitization of spiny-neuron glutamatergic receptors. glutamate-mediated striatal dysregulation, subsequently, modifies basal ganglia output system in ways that favor the appearance of parkinsonian motor response complications. at a molecular level, transcriptional activation of striatal creb contributes to the persistent expression of the levodopa-induced motor response alterations. conceivably, a safer and more effective therapy for all stages of pd can be provided by drugs that target intracellularly on striatal kinases or phosphotases, or by agents that interact extracellularly on non-dopaminergic striatal receptors such as ampa and nmda, adenosine a2, adrenergic a2, opiod, and serotonergic 2b. the primary cause of parkinson's disease is a loss of dopamine in the corpus striatum. it has been postulated that this effect leads to disinhibition of the striopallidal pathway and, secondarily, to a functional shift towards glutamatergic stimulation. the aim of the present study was to find out whether inhibition of glutamatergic transmission at a level of metabotropic glutamate receptors (mglurs) in the striatum may alleviate parkinsonian-like symptoms in rats. the non-competitive antagonist of receptor subtype 5 (mglur5), mpep (1.0-10 mg/kg ip), or the agonist of group ii mglurs, ly354740 (5-10 mg/kg ip), reduced the haloperidolinduced muscle rigidity and catalepsy. intrastriatal injections of the antagonist of mglur1, (rs) aida (7.5-15 µg/0.5 µl), but not of the agonist of group ii mglurs, 2r,4r-apdc (7.5-15 µg/0.5 µl), inhibited the muscle rigidity induced by haloperidol. in order to search for an influence of mglurs on the striopallidal pathway, the effect of mpep or of the agonist of group ii mglurs, dcg-iv, on the preproenkephalin mrna expression in the striatum was examined. the obtained results suggest that blockade of group i mglurs, or stimulation of group ii mglurs may be important to the amelioration of parkinsonian symptoms. striatal mglurs may contribute to at least some of these effects. several lines of evidence suggest an important role of glutamate in depression. the involvement of group i mglurs in depression has also been proposed. thus, we decided to evaluate whether group i mglurs antagonists have antidepressantlike effects. we also investigated if antidepressant treatment influences group i mglu receptors in the brain. the experiments were performed on male wistar rats (200-250 g) and male c57bl/6 mice (22-26 g). aida (group i mglurs antagonist) given i.v. in the dose of 50 µg, decreased the immobility time in the despair test in rats. mpep (noncompetitive, systemically active mglur5 antagonist) given i.p., was not effective in the despair test in rats. however, in doses of 1.0, 10 and 20 mg/kg, it significantly decreased the immobility time of mice in the tail suspension test. moreover, the deficit in passive-avoidance learning, which was observed in bulbectomized rats, was reversed by chronic, but not acute mpep (10 mg/kg) treatment. prolonged imipramine treatment resulted in significant increase of the level of expression of mglu5 receptors in the ca1 field of the hippocampus, while prolonged electroconvulsive shock treatment (ect) enhanced significantly the chemiluminescence of mglu5 receptors in the ca3 field. the results indicate that group i mglu receptors are modified by chronic antidepressant treatment and that group i metabotropic glutamate receptors antagonists may play a role in the therapy of depression. (this study was supported by kbn grant no. 4.po5a.091.17) institute of pharmacology, polish academy of sciences, krakow, poland chronic exposure to nicotine, alcohol, opioids, sedatives, and cannabis results in development of drug dependence that becomes evident upon a cessation of drug administration and expresses itself as a withdrawal syndrome (with its physiological and motivational manifestations). adaptations at the nmethyl-d-aspartate receptor (nmda-r) complex have been observed in different brain areas during chronic exposure to, and upon withdrawal from, opioids, ethanol, benzodiazepines and barbiturates. behavioral studies employ the assessment of the effects of nmda-r antagonists on: a) the development of dependence (nmda-r antagonists are co-administered with the drug), b) the maintenance of dependence (nmda-r antagonists are administered to animals with pre-established dependence, and -most relevant to the clinical situation -c) on the expression of drug dependence (assessment of the withdrawal severity in subjects with nmda-r antagonists administered just before the expected emergence of withdrawal). the development of dependence to opioids and benzodiazepines is significantly retarded by nmda-r antagonists. studies from this laboratory demonstrate similar inhibition by nmda-r antagonists of the maintenance of opioid dependence. both in rodents and humans, the expression of opioid antagonist-precipitated as well as spontaneous (natural) withdrawal is inhibited by nmda-r antagonists, and animal data demonstrate similar inhibition of the expression of dependence produced by ethanol, barbiturates and benzodiazepines. the involvement of the excitatory amino acid, glutamate and the inhibitiory amino acid, gamma-amino butyric acid (gaba) in the pathophysiology of spinal cord trauma is not known in details. this investigation is focused on the involve-ment of glutamate and gaba in a rat model of spinal cord injury using immunohistochemistry. spinal cord injury induced by an incision into the right dorsal horn of the t10-11 segments resulted in profound edema formation and cell damage in the adjacent t9 and t12 segments at 5 h. pretreatment with h-290/51 (50 mg/kg, p.o.), a potent antioxidant compound, effectively reduced the edema formation and cell injury following trauma. at this time period, untreated traumatised rats exhibited a marked increase in glutamate immunoreactivity and a distinct decrease in gaba immunostaining in the t9 and t12 segments compared to the control group. the changes in glutamate and gaba immunoreactivity in traumatised rats were considerably attenuated by pretreatment with h-290/51. these results suggest that (i) oxidative stress contributes to alterations in glutamate and gaba in spinal cord injury, (ii) glutamate and gaba are contributing to edema formation and cell damage and (iii) the antioxidant compound h-290/51 has a potential therapeutic value in the treatment of spinal cord injuries. dov pharmaceutical, inc., hackensack, new jersey, u.s.a. both preclinical (i.e., behavioral despair models) and clinical studies indicate that compounds reducing transmission at nmda receptors are antidepressant. conventional antidepressants may be viewed as "monoamine-based", increasing the synaptic availability of serotonin, norepinephrine, and/or dopamine. however, chronic administration of of conventional antidepressants alters both mrna levels encoding nmda receptor subunits and radioligand binding to this family of ligand-gated ion channels in circumscribed areas of the cns indicating that nmda receptors may be a downstream target of these monoamine-based agents. we have recently reported (li, et al., neuropharmacology, in press ) that a class of ampa receptor potentiators also exhibits antidepressant-like actions in preclinical models. in this presentation, i will describe how these two distinct, and (at a cellular level) seemingly diametric approaches employing glutamatergic mechanisms converge on intracellular targets that are also impacted by chronic treatment with biogenic amine-based agents. kainic acid is an essential pharmacological tool for many forms of neurobiological research. until several years ago, all commercially available kainic acid was derived from a single biological source (digenia simplex). commercial isolation of kainic acid in japan ceased in 1999, creating a void in the marketplace. recently several different companies have become providers of kainic acid, but each uses a different source of the compound (2 biological and 1 synthetic) and different isolation procedures. our objective was to use three common assay systems to evaluate the comparative pharmacological and neurotoxicological properties of these three sources of kainic acid. dose response curves, both alone and in the presence of receptor selective antagonists, were constructed for each kainate formulation using (a) cerebellar granule neurons in culture, (b) isolated hippocampal slice preparations, and (c) whole animal behavioural toxicity studies. preliminary results reveal many similarities, but also distinct differences between the three formulations, especially when challenged with antagonists for different eaa receptors. full results will be presented and discussed with respect to their implications for both extending the known kainite literature and for future studies employing kainic acid as a ligand in both mechanistic investigations and in animal models of neurodegenerative disease. our results from in vitro studies further elucidate the role of cell-cycle related proteins in neuronal apoptosis induced by excitotoxins. exposure of primary cerebellar neurons to toxic concentrations of glutamate was found to produce a significant, short lasting increase in the expression of p53 and cdc2. transcriptional activity of p53 was shown by increased p53 dna binding activity and by the concomitant induction of the cdk inhibitor p21, the cell cycle regulator gadd 45 and the apoptotic induced bax. cell-cycle proteins are also expressed concomitantly to dna damage in neurons undergoing excitotoxic degeneration. we found that excessive activation of glutamate receptor by nmda results in the formation of 8-oh-deoxyguanosine, which is a marker of oxidative dna damage. in addition, the expression of the dna repair factor msh2 increases in cultured cerebellar neurons or in ca3 pyramidal cells that have been challenged with excitotoxins. excitotoxicity may thus provide a further example of how re-expression of cell-cycle proteins might be tightly connected to dna damage and repair in neurons. rush-presbyterian-st. luke's medical center, chicago, u.s.a. patients with parkinson's disease by definition benefit from levodopa therapy. however, after 5 years of therapy 50% of patients experience motor response complications (mrc's): the benefit from each dose becomes shorter (wearing-off), more unpredictable (on-off) and associated with involuntary movements (dyskinesias). when dyskinesias first arise, they are associated with high levodopa levels and may be prevented or minimized by lowering levodopa intake. later on, the therapeutic window of levodopa narrows progressively and dyskinesias occur at doses equal to those needed to induce an antiparkinson effect. while the pathogenesis of motor complications remains incompletely understood, recent clinical studies implicate mechanisms downstream from the degenerating nigrostriatal dopamine system, possibly involving glutamatergic projections to the basal ganglia. in a rat model of pd, blockade of striatal glutamate receptors of the n-methyl-d-aspartate (nmda) subtype reverses levodopa-induced motor fluctuations. similarly, in 1-methyl-4-phenyl-1,2,3,6tetrahydropyridine (mptp) lesioned primates, several nmda-antagonists reduce levodopa-associated dyskinesias. in parkinsonian patients the nmda-antagonists dextromethorphan, dextrorphan and amantadine improve dyskinesias as well. these findings have lead to the suggestion that hyperfunction of nmda receptors on striatal efferent neurons, as a consequence of chronic non-physiologic dopaminergic stimulation, contributes to the pathogenesis of motor response complications. protein misfolding and aberrant polymerization are salient features of virtually all central neurodegenerative disorders, including alzheimer's disease (ad), parkinson's disease, polyglutamine diseases, tauopathies, and prion diseases. in many instances, a single amino acid change can predispose to disease by increasing the production and/or changing the biophysical properties of a specific protein. possible pathogenic similarities among the cerebral proteopathies suggest that therapeutic agents interfering with the proteopathic cascade might be effective against a wide spectrum of diseases. however, testing compounds preclinically will require diseaserelevant animal models. numerous transgenic mouse models of ad-like pathology have now been produced. our studies have found that tg2576 mice overexpressing human -amyloid precursor protein (huapp695k670n/m671l) produce copious deposits of diffuse and compact -amyloid as they age, and that females are more susceptible than are males (callahan et al., am. j. pathol. 158, 1173 -1177 , 2001 . recently, we also found that the overexpression of p25 protein, an activator of the kinase cdk5, results in tau hyperphosphorylation, axonopathy and severe motor deficits in transgenic mice, in the absence of neurofibrillary tangles. none of the existing transgenic models of -amyloidosis or tauopathy fully recapitulates the pathology of ad. in an attempt to more authentically model the human disease, we infused dilute ad-brain extracts into tg2576 mice at 3-months of age (i.e. 5-6 months prior to the usual onset ofamyloid deposition). we found that infusion of ad brain extracts results in: 1) earlier and more abundant deposition of -amyloid in app-transgenic mice (kane et al., j. neurosci. 20, 3606-3611); 2) evidence for the spread of pathology to other brain areas, possibly by neuronal transport mechanisms; and 3) tau hyperphosphorylation (but not neurofibrillary pathology) in axons passing through the injection site. the seeding ofamyloid by ad brain extracts suggests pathogenic similarities between -amyloidoses such as ad and other cerebral proteopathies, and could provide a new model for studying the proteopathic cascade and its neuronal consequences in neurodegenerative diseases. supported by warner-lambert/pfizer. purpose: the effects of essential amino acid deficiencies on function of cornea and lens were investigated. methods: dietary deficiencies of tryptophane and methionine were studied in young rats over 3 months. transparency of cornea and lens were evaluated using slitlamp microscope and scheimpflug camera. after sacrifice, lens fresh weight and crystallin patterns were determined to evaluate effects on lens growth and protein synthesis. results: methionine deficiency had no effect on the parameters investigated. tryptophane deficiency caused severe loss of body weight in both rat strains (brown-norway, bn; sprague-dawley, sd), sd rats also lost their hair. they developed corneal neovascularisations and cortical cataracts. bn rats developed faint neovascularisations and a discontinuity zone in the lens. diet intermission arrested pathological processes restarting when feeding diet again. this observation is supported by lens fresh weight data. dna staining evidenced that tryptophane deficiency arrested lens fiber maturation. conclusion: a difference has been found for 2 essential amino acids in their effects on transparency of cornea and lens. tryptophane deficiency stimulated corneal neovasculariseration, but arrested lens fiber cell maturation. the difference in reaction of cornea and lens to tryptophane deficiency between bn and sd rat eyes remains to be elucidated. dynorphin is a neuropeptide that is present in the dorsal horn of the spinal cord. the peptide is actively involved in pain processing pathways. however, its involvement in spinal cord injury is not well known. alteration in dynorphin immunoreactivity occurs following a focal trauma to the rat spinal cord. infusion of dynorphin into the intrathecal space of the cord results in ischemia, cell damage and abnormal motor function. antibodies to dynorphin when injected into the intrathecal space of the spinal cord following trauma improves motor recovery and reduces edema and cell changes. however, influence of dynorphin on trauma induced alteration in spinal cord bioelectrical activity is still not known. spinal cord evoked potentials (scep) are good indicator of spinal cord conduction that are altered following trauma. therefore, in present investigation, influence of dynorphin antibodies on trauma induced changes in scep was examined in our rat model. in addition, spinal cord edema formation and microvascular permeability disturbances were also investigated. our results show that intrathecal administration of dynorphin antiserum prior to injury has a beneficial effect on trauma induced electrical activity, microvascular permeability disturbances, and edema formation. these observations indicate that dynorphin is somehow involved in the altered bioelectrical activity of the spinal cord and participates in the pathophysiological processes leading to cell injury. fatty-acid binding proteins (fabps) are involved in the intracellular binding, targeting and transport of long-chain fatty acids (fas) to modulate cell growth and/or differentiation. fabp form a family of proteins displaying tissue-specific expression. the expression of brain type fabp (b-fabp) is spatially and temporally correlated with neuronal differentiation during brain development. heart type fabp (h-fabp) is widely distributed and present in skeletal muscles, kidney, lung, brain and endothelial cells. it is neuron-specific in postnatal brain and participates in neurite formation and synapse maturation. epidermal type fabp (e-fabp) is expressed at high levels during neurogenesis, neuronal migration, and terminal differentiation. although all three fabps could be involved in normal brain function in prenatal and postnatal life, a neurobiological role of fabps in neurodegenerative diseases has not been reported yet. these made us evaluate the protein levels of fabps in brains from patients with down syndrome (ds) and alzheimer's disease (ad) and fetal cerebral cortex with ds using two-dimensional (2-d) gel electrophoresis with subsequent matrix-assisted laser desorption ionization mass spectroscopy (maldi-ms) identification and specific software for quantification of proteins. in fetal brain, b-fabp and e-fabp levels were comparable between control and ds. in adult brain, b-fabp was significantly increased in occipital cortex of ds, and h-fabp was significantly decreased in ds (frontal, occipital, parietal cortices) and ad (frontal, temporal, occipital and parietal cortices). we conclude that aberrant expression of fabps, especially h-fabp in neurodegenerative diseases could be involved in impaired neurite outgrowth and synapse maturation. in our previous paper, it was shown that gaba-a receptor antagonist picrotoxin suppressed etoh (ethanol) selfadministration. recently, several authors indicated that systemic injection of dopamine or serotonine agonists reduced ethanol drinking in rats. therefore, in the present study we investigated the effects of thip (4,5,6,7-tetrahydroizokasazolo, 5,4-c pyridin-3-ol) gaba-a receptor agonist in naive and long-term ethanol-experienced rats on etoh selfadministration and on cardiovascular system. adult 13-17week-old male, normotensive wistar-kyoto (wky) and spontaneously hypertensive rats (shr) were used. naive rats were examined according to smith method. long-term ethanolexperienced rats were studied according to boyle method. thip was injected in naive rats at a dose of 8 and 16 mg/kg i.p. metabotropic glutamate receptors are coupled to phospholipase c stimulation and adenylyl cyclase inhibition through g-proteins. c6 glioma cells, that endogenously express the phospholipase c coupled metabotropic glutamate receptor type, were treated with different specific agonists of these receptors and the effect of these treatments on different components of metabotropic glutamate receptor pathway was studied by radioligand binding, phospholipase c activity and rt-pcr assays. agonists treatment caused a decrease in l-[ 3 h]glutamate binding to intact cells and membranes in a time dependent manner being maximum at 3-6 hours and recovered at 24-36 hours. this decrease was associated with a significant increase in the mrna level coding mglurs. no changes on g q/11 mrna level were detected in any case. however, a significant decrease in l-glutamate stimulated phospholipase c activity was detected after agonist treatments in both membranes and intact cells. this decrease was not associated to significant variations in mrna level coding phospholipase c 1 isoform. all these results suggest that agonist exposure causes a desensitisation of glial metabotropic glutamate receptor decreasing not only receptors number but its functionality. in this study the interaction between these two nuclei were investigated by means of microinjection and microdialysis techniques in sprague-dawley rats. steroetaxic surgery was performed by placing intracerebral parenchymal microinjection cannula into the right dmh and microdialysis probe into the left pvn. iliac artery was also cannulated to monitor the pulsatile blood pressure and heart rate by means of pressure transducer connected to a polygraph microinjection of 50 pmol nmda into the dmh was performed and microdialysis perfusates were collected simultaneously from the pvn in conscious rat model. γ-aminobutyric acid (gaba) and l-glutamic acid levels were analyzed by an isocratic hplc (high pressure liquid chromatography) method with the aid of a fluorescent detector. microinjection of 50 pmol nmda into dmh produced significant increases in mean arterial pressure and heart rate. nmda microinjection into the dmh produced significant increase in l-glutamic acid release in the pvn, but no significant change in gaba release was observed. these results suggest that stimulation of dmh by nmda results in subsequent stimulation of the pvn. [this study was sponsored by marmara university research foundation (project no: 1998/sag/38).] and in long-term ethanol-experienced rats only at a dose 16 mg/ kg i.p. control group (cg) received saline 3 ml/kg i.p. as can be seen in fig. 1 and table 1 the lower consumption of ethanol in shr in comparison to wky rats was observed. systemic injection of thip decreased dosedependently etoh intake in naive rats of both strains. this effect was more pronounced in shr (fig. 1) . similar phenomenon was observed after thip injection in long-term ethanolexperienced rats. there were no effect on systolic blood pressure and heart rate after thip treatment. born-bunge foundation, university of antwerp, and university of ghent, belgium increased neuronal excitability may underlie some of the neurological complications in uremic patients. in an effort to identify candidate neuroexcitatory compounds, 17 different uremic retention solutes, including several amino acids and amino acid derivatives, were applied to mouse spinal cord neurons in primary dissociated cell cultures. using the tight-seal whole-cell technique, a few of the candidate toxins were shown to evoke whole-cell currents in cells clamped at ϫ60 mv. in a first survey, each of the solutes was briefly applied in a concentration of 5 mm. significant inward whole-cell currents were evoked by guanidinosuccinate, spermine, and 3-indoxyl sulfate, whereas phenol evoked an outward current. further experiments indicated that guanidinosuccinate-evoked whole-cell currents were due to activation of nmda-type glutamate receptors in concentrations similar to those found in uremic patients. high (mm) concentrations of spermine activated voltage-gated calcium channels, whereas low (µm) concentrations were found to potentiate guanidinosuccinate-evoked currents through its action on the nmda receptor-associated polyamine binding site. whole-cell currents evoked by 3indoxyl sulfate or phenol seemed to be due to complex interaction with several different ion channels. we conclude that guanidinosuccinate-evoked nmda receptor activation, possi-bly potentiated by the neuroexcitatory effects of polyamines and other putative uremic neurotoxins, could be an important mechanism underlying the increased neuroexcitability in uremic brain. glutamine (gln) is one of the key metabolites in the cns (energy metabolite, precursor of neurotransmitter amino acids, end product of ammonia detoxication, osmolyte), and as such is a routine supplement of cns cell culture media. c6 glioma cells relatively easily adapt to culturing in a gln-deprived medium. the present study investigated the effects of gln deprivation on the characteristics of the different systems that mediate gln cell membrane transport in the cells. in contrast to a variety of cns and non-cns cells, the absence of gln did not derepress the methyl-amino-isobutyric acid (meaib)-sensitive ("system adependent") uptake. system asc became relatively more-, and system n less active than in cells grown in the presence of gln, but the ion -and substrate specificity of the uptake remained unaltered. system asc in c6 cells grown in a glnsupplemented medium shows two features distinct from most other cell types: a) strong ph sensitivity and b) partial tolerance of lithium substitution, pointing to domination of system asct2 -an asc variant strongly expressed in cultured astrocytes. cells grown in gln-deprived medium lost lithium tolerance, but not ph-dependence of the uptake, their properties thus resembling system glnt (sat1), a neuron-specific variant of system a. by contrast, transport of threonine, a standard asc system substrate, was not affected by gln deprivation and showed neither ph dependence nor lithium tolerance, which is typical of an asc in all the non-cns tissues. (supported by scsr grant no. 4 p05a 060 18.) the classical the hypothalamic-neurohypophysial system (hns) is comprised of neurons originating within the supraoptic nucleus (son) which project to the neurohypophysis to release the nonapeptides oxytocin (oxt) and vasopressin into the blood after appropriate stimulation. previous experiments have shown that a single social defeat experience triggers the release of oxt from somata and dendrites into the extracellular fluid of the son, but not from axon terminals in the neurohypophysis. to further investigate the regulatory mechanisms underlying this dissociated release, we exposed male wistar rats to a 30-min social defeat experience and monitored the release of the inhibitory amino acids gamma amino butyric acid (gaba) and taurine into the son using microdialysis. social defeat caused a significant increase of the intra-son pre-stress basal release). to reveal the physiological significance of the intrahypothalamically released gababicuculline, a specific gaba a -receptor antagonist -was administered into the son by retrodialysis. this treatment increased significantly the release of oxt both within the son (200%; p ͻ 0.05 vs. pre-stress basal release) and -as measured via chronically implanted jugular venous catheters -into blood under basal and stress conditions (up to 200%; p ͻ 0.01 vs. prestress basal release). however, bicuculline did not affect plasma vasopressin. these data demonstrate that gaba is released within the son during social defeat to act as an inhibitor of both, central and peripheral oxt secretion during emotional stress. the mechanism described here contributes to the regulatory capacity of the hns to ensure the appropriate involvement of oxt in the stress response of the animal (supported by dfg, en 366-21). down syndrome (ds) is the most common human chromosomal abnormality caused by an extra copy of chromosome 21 and characterized clinically by somatic anomalies, mental retardation and precocious dementia. the phenotype of ds is thought to result from overexpression of a gene or genes located on the triplicated chromosome or chromosome region. reports that challenge this notion, however, have been published. to add to this body of evidence, the expression ofamyloid precursor protein (app), ets-2 and collagen α1 (vi) chain precursor, encoded on chromosome 21, was investigated in fetal brain by western blot and two-dimensional electrophoresis (2-de). western blot detected app and ets-2 that migrated at ϳ75 and 50 kda, respectively. subsequent densitometric analysis of app and ets-2 immunoreactivity did not produce any significant change between controls and ds. since the metabolic fate of app determines the propensity of amyloid production, the expression of the secreted forms of app (sapp) had been examined. neither the expression of sappα nor sapp showed any detectable changes among the two groups. collagen α1 (vi) chain precursor, a protein resolved as a single spot on 2d gel was identified by matrix associated laser desorption ionization mass spectroscopy. quantitative analysis of this spot using the 2d image master software revealed a significant decrease in fetal ds (p ͻ 0.01) compared to controls. linear regression analysis did not show any correlation between protein levels and age. the current data suggest that overexpression per se can not fully explain the ds phenotype. apoptosis is the mechanism by which cells are programmed to die under a wide range of physiological and developmental stimuli. accumulating evidence indicates that enhanced apoptosis (programmed cell death) in down syndrome (ds) may play a role in mental retardation and precocious neurodegeneration of the alzheimer-type. in this regard, alteration of several apoptosis related proteins have been reported in adult ds brain. fetal ds neurons exhibited increased reactive oxygen species leading to early apoptosis, however, expression of apoptosis related proteins in fetal ds, has never been considered. to address this issue, we investigated the expression of proteins involved in apoptosis including fas (cd95, apo-1), caspase-3, bcl-2 and annexins in the cerebral cortex of control and ds fetal brain by western blot and two dimensional electrophoresis. here, we report that no detectable changes were obtained in fetal ds brain in the expression of fas, caspase-3, bcl-2 and annexins (i, ii, v, and vi) compared to controls. in parallel experiment, we also examined the expression of neuron specific enolase (nse), a neuronal marker found to be decreased in adult ds brain, to see if there is any neuronal loss and no difference was observed between the two groups. protein expression did not correlate with age. the unchanged levels of fas, bcl-2 and annexins together with unaltered caspase-3 expression, a predominant caspase that executes apoptosis in the developing nervous system, suggest that enhanced apoptosis may not be apparent in fetal ds brain as demonstrated for adult ds brain. introduction. among the various metabolites indicating neuronal damage, amino acids are regarded particularly important. detection of amino acids by microdialysis is currently introduced as a neuromonitoring tool in patient care. here, we present changes in the extracellular concentrations of various amino acids in stroke patients and in experimental stroke in cats. method. cat focal ischemia was produced by occlusion of the middle cerebral artery (mca) for 1 h followed by 2 h reperfusion. glutamate, aspartate, gaba, taurine, glycine, serine, glutamine, methionine, threonine, tyrosine, asparagine, valine, phenylanaine, isoleucine and leucine were sampled by microdialysis in the ischemic core and subsequently analyzed by hplc. human microdialysis was performed in patients with large mca infarction. the microdialysis probes were inserted into primarily non-infarcted tissue in the border zone of the ischemic territory. results. transmitter amino acids rose immediately after occlusion in the cat model. correspondingly, these substances increased sharply in the human brain, when the tissue around the probes became infarcted, as shown by positron emission tomography (pet) and ct scan. in contrast, structural amino acids did not show marked increases or even decreased during severe ischemia in both, experimental ischemia and stroke patients. these substances did increase, however, when the brain tissue was only slightly ischemic, i.e. after reperfusion of the cat brain, when brain swelling occurred, or in human brain, when tissue did not show any infarction in the ct scan but hypoperfusion in the pet image. conclusion. extracellular amino acids detected by microdialysis can serve as markers for secondary ischemia. severe ischemia is reflected by rapid increases of transmitter amino acids, due to various mechanisms including synaptic release and reversal of reuptake systems. oligemia seems to be reflected by slow increases of structural amino acids, possibly due to a reduction in cerebral protein synthesis. apoptosis has been implicated in the selective neuronal loss of down syndrome (ds). apoptosis activates a family of cysteine proteases with specificity for aspartic acid residues referred to as, caspases that play a key role in dismantling a cell committed to die. caspases activity is regulated by a variety of proteins that possess a domain resembling the prodomains of caspases. little is known, however, about the changes of caspases and their regulatory proteins in ds. here, we investigated levels of nine such different proteins by western blot technique in frontal cortex and cerebellum of control and ds subjects. the protein levels of dff45 (dna fragmentation factor 45), and flip (fadd like interleukin-1 -converting enzyme inhibitory proteins) were significantly decreased whereas that of rick (rip-like interacting clarp kinase) increased in both regions of ds. in contrast, cytochrome c, apaf-1 (apoptosis protease activating factor-1), procaspase-9 and arc (apoptosis repressor with caspase recruitment domain) were unchanged. procaspase-3 and -8 were significantly decreased in frontal cortex but no significant change was observed in cerebellum. regression analysis revealed no correlation between postmortem interval and levels of the investigated proteins. however, inconsistent correlation was found between age and levels of proteins as well as amongst the density of individual proteins. these findings demonstrate that dysregulation of apoptotic proteins does exist in ds brain and may underlie the neuropathology of ds. the study further suggests that apoptosis in ds may occur via the death receptor pathway independent of cytochrome c. hence, therapeutic strategies that target caspase activation may prove useful in combating neuronal loss in this disorder. in order to examine the differential roles of nitric oxide (no) induced by either endothelial no synthase (enos) or neuronal no synthase (nnos) after transient cerebral ischemia, we investigated the effects of the relatively selective cnos inhibitor, l-n 5 -(1-iminoethyl)ornithine (l-nio), the relatively selective nnos inhibitor, 7-nitroindazole (7-ni) and the no scavenger, 2-(4-carboxyphenyl)-4,4,5,5tetramethylimidazole-1-oxyl 3-oxide (ptio) on hippocampal dysfunction caused by cerebral ischemia. we measured no concentration, mean arterial blood pressure (mabp), hippocampal blood flow, direct current potential, ca1 population spike (ps) and release of amino acids from rat hippocampus after transient forebrain ischemia, which was induced by 4vessel occlusion for 10 min. l-nio (20 mg/kg), 7-ni (25 mg/kg) and ptio (1 mg/kg) were administered intraperitoncally 20 min before ischemia. ptio, 7-ni and l-nio reduced ischemiainduced no production in the hippocampus during the early period of reperfusion. the rank order of inhibitory potency was ptio ͼ 7-ni ͼ l-nio. l-nio, but not 7-ni, reduced hippocampal blood flow during ischemia and increased mabp before, during and after ischemia, compared with the vehicle group. ptio increased mabp during and after ischemia. ptio and 7-ni, but not l-nio, reduced amplitude of anoxic depolarization induced by ischemia. 7-ni recovered in part ps amplitude 60 min after ischemia. 7-ni, but not l-nio, reduced ischemiainduced release of aspartate and glutamate, but not taurine. the present study provides further evidence for the idea that in the early stages of transient forebrain ischemia, enos-derived no has a neuroprotective effect in the hippocampus, while nnos-derived no has a neurotoxic effect. the estrogen affects brain protein synthesis in ovariectomized female rats k. hayase 1 , m. tanaka 1 , k. tujioka 1 , e. hirano 1 , and h. yokogoshi 2 1 department of home economics, aichi university of education, kariya, aichi, and 2 laboratory of nutritional biochemistry, school of food and nutritional sciences, the university of shizuoka, japan the purpose of this study was to determine whether 17-estradiol affected the rate of brain protein synthesis in ovariectomized female rats. experiments were conducted on three groups of 12 wk old female rats: group 1. ovariectomized to reduce the level of plasma estradiol; group 2. ovariectomized and treated with estradiol; and group 3. sham-operated control. the fractional rates of protein synthesis in brain of ovariectomized rats treated with estradiol were significantly greater than in ovariectomized rats without estradiol treatment. in brain, the rna activity [g protein synthesized/(g rnaᮀd)] significantly correlated with the fractional rate of protein synthesis. the rna concentration (mg rna/g protein) was not related to the fractional rate of protein synthesis in any organ. the results suggest that estrogen treatment of ovariectomized female rats is likely to increase the rate of protein synthesis in the brain, and that rna activity is at least partly related to the fractional rate of brain protein synthesis. we have synthesized a series of new peptides that have demonstrated potent antidepressant activity in animal models for depression and in phase iia and iib clinical trials. mif-1 (prolyl-leucyl-glycinamide) an endogenous brain peptide has been reported to have some clinical activity in patients with unipolar depression with few apparent side effects. we have undertaken a study to determine the effect of molecular structural changes on the antidepressant activity of this peptide. we evaluated our new derivatives in a stress-induced animal model for depression, i.e. porsolt test, we have found that 4-f-phe-4-oh-pro-arg-gly-trp-nh 2 (inn 00835) is superior in all the statistical parameters used. in comparative testing inn 00835 was more active than prozac (fluoxetine) and zoloft (sertraline) in our antidepressant model. a u.s. patent has been granted on these compounds. the clinical results of inn 00835 show that it is effective in over 80% of depressed subjects when blood levels exceeded therapeutic threshold with no significant side effects. inn 00835 has a rapid onset of action, 3-5 days (vs. 2-6 weeks for currently marketed products) with sustained effects for months following 5 to 10 doses over 1-2 weeks. h. iwama 1 , 2 , a. umino 2 , a. hashimoto 2 , k. takahashi 2 , n. yamamoto 2 , and t. nishikawa 1,2 1 section of psychiatry and behavioral science, tokyo medical and dental university graduate school, and 2 department of mental disorder research, national institute of neuroscience, ncnp, tokyo, japan using an in vivo dialysis technique, we have studied the extracellular contents of endogenous free d-serine in comparison with that of l-serine, glycine and l-glutamate in the brain of the freely moving rat. a high amount of d-serine was detected in the dialysate obtained from the medial prefrontal cortex and striatum, whereas the cerebellar dialysate contained only a trace concentration of the d-amino acid. intra-medial prefrontal cortex perfusion of a sodium channel activator, veratrine, augmented the extracellular release of glycine and l-glutamate but a slight decrease in that of d-serine in a tetrodotoxin-sensitive manner in the prefrontal area. moreover, selective destruction of neuronal cell bodies in the medial frontal region by means of local infusion of an excitotoxin quinolinate resulted in a marked reduction of extracellular and tissue levels of d-serine in the infused prefrontal region. these findings suggest that endogenous d-serine might be liberated into the extracellular space from non-neuronal cells or certain exceptional neuronal cells probably by a carrier-mediated process in the mammalian prefrontal cortex. also, the endogenous d-amino acid has been indicated to be accumulated or synthesized, at least in part, in the neuronal cells. nucleoside diphosphate kinase (ndpk) catalyzes a transfer of the terminal phosphate from nucleoside triphosphates ((d)ntps) to nucleoside diphosphates ((d)ndps) and has been suggested to be involved in the regulation of wide variety of cellular functions. in addition, ndpk isoforms (a and b) are encoded by nm23 genes (h1 and h2) , which are related with the metastatic potential of some tumors. although ndpk/ nm23 has been also implicated to modulate neuronal cell proliferation, differentiation and neurite outgrowth, a neurobiological role of ndpk/nm23 in neurodegenerative diseases has not been reported yet. here we evaluated the protein levels of ndpk-a/nm23-h1 in brains from patients with down syndrome (ds) and alzheimer's disease (ad) using twodimensional (2-d) gel electrophoresis with subsequent matrixassisted laser desorption ionization mass spectroscopy (maldi-ms) identification and specific software for quantification of proteins. ndpk-a/nm23-h1 was significantly decreased in brain regions (frontal, occipital, parietal cortices) of both ds and ad compared to controls. we conclude that the down-regulated ndpk-a/nm23-h1 upon neurodegeneration could play a pivotal role in a wide range of neurobiological functions such as neurite outgrowth and consequently these could result in functional disturbance of the nervous system in ds and ad. brain α-endosulfine is manifold decreased in brains from patients with alzheimer's disease: a tentative marker? and drug target? α-endosulfine has the sulfonylurea-like ability to block atp-sensitive potassium (k atp ) channels and is expressed in a wide range of tissues. although the blockade of k atp channels has been reported to be involved in the release of neurotransmitters, the neurobiological role of α-endosulfine has not been studied yet. we examined the levels of αendosulfine protein in frontal cortex and cerebellum from patients with alzheimer's disease (ad). α-endosulfine was extremely decreased in both regions of ad compared to controls. this could result in the continuous opening of k atp channels with subsequent decrease of neurotransmitters release and change of potassium fluxes. this study is of great significance for providing a neurobiological function of α-endosulfine in brain and furthermore, α-endosulfine could serve as a useful marker for the diagnosis of ad and a target for drug treatment. children's hospital heidelberg, and department of pharmacology and toxicology, university of marburg, germany d-2-hydroxyglutaric aciduria is an inherited neurometabolic disorder of unknown etiology characterized by progressive neurodegeneration of vulnerable brain regions during infancy and early childhood, resulting in psychomotor retardation, hypotonia, seizures, macrocephaly, enlarged lateral ventricles, delayed cerebral maturation as frequent neurological presentation in affected children. the disease is biochemically characterized by the accumulation of d-2hydroxyglutarate (d-2), which is structurally similar to lglutamate (ϭ 2-amino-glutarate). we therefore investigated in primary neuronal cultures from chick and rat, whether d-2 induces excitotoxic neuronal damage. here we report that d-2 decreased cell viability in a concentration-and time-dependent fashion by disturbance of intracellular calcium homeostasis as determined by fura-2 measurement. furthermore, fluorescence microscopy using dihydrorhodamine-123 revealed an increased generation of reactive oxygen species (ros) elicited by expo-sure to d-2. n-methyl-d-aspartate (nmda) receptor blockade specifically prevented excitotoxic neuronal damage as well as increased calcium influx and ros production, suggesting that d-2 is an agonist at nmda receptors. patch-clamp investigation confirmed that d-2 activated recombinant nmda receptors in hek293 cells. furthermore, activity measurement of single respiratory chain complexes revealed a specific inhibition of complex v activity by d-2. we conclude that excitoxic mechanisms contribute to the neuropathology of d-2hydroxyglutaric aciduria, highlighting new neuroprotective strategies for this neurometabolic diseases. these studies were designed to determine the effects of aging and an aging intervention on nmda subunit expression. in situ hybridization and receptor autoradiography were performed on naïve or behaviorally-tested c57bl/6 mice of different ages (3, 10-15, and 26-30 months old) and diet groups (ad lib-fed and diet restricted). there were age-related decreases in both e2 and z1 mrna density in naïve, ad lib-fed mice. correlations were found between changes in e2 subunit mrna and agonist binding and z1 mrna expression and antagonist binding. diet restriction significantly improved learning ability, slightly spared glutamate binding to nmda sites and improved z1 mrna expression in older mice. significant correlations were found between agonist binding and both learning ability and e2 and e1 mrna density. learning ability in the old mice also correlated with the ratios of mrna expression for e1 and e2 and/or z1 subunits. these results suggest that changes in nmda receptor binding and the relationship between subunit expression levels are important for maintaining memory functions in older animals. extracts of st john's wort (hypericum perforatum l.) are widely prescribed for the treatment of mild to moderate depression and the putative antidepressant constituent is probably hyperforin. in this study the effect of hyperforin was investigated on the release of neurotransmitter amino acids. coronal cortical slices (400 mm) were cut and perfused with gassed (95% o2, 5% co2) acsf at 37°c. two-minute samples of perfusate were collected and aspartate and glutamate were assayed by hplc. potassium-and veratridine-stimulated release was elicited by administering 2 pulses of kϩ (60 mm) or veratridine (20 mm) 30 minutes apart. in control experiments the second kϩ pulse elicited glutamate release which was 80% of the first pulse. hyperforin (5 mm) perfused for 30 minutes prior to, and during, the second kϩ pulse significantly increased glutamate release to 170% (p ͻ 0.001, n ϭ 6-8). release elicited by the second veratridine pulse was 70% of the first pulse for both glutamate and aspartate. hyperforin (5 mm) increased this release to the second pulse to 160% and 130% respectively (p ͻ 0.001, n ϭ 6-8). when perfused on its own for 30 minutes, hyperforin (5 mm) increased the basal release of glutamate (p ͻ 0.001, n ϭ 4-5). in conclusion, the increase in the release of neurotransmitter amino acids observed following hyperforin is possibly mediated through a facilitatory action on voltage-operated ca2ϩ or naϩ channels. glaxosmithkline group, glaxo wellcome s.p.a., medicines research centre, verona, italy n-methyl-d-aspartate (nmda) receptors are ligand gated ion channels widely distributed in mammalian brain, which play a crucial role in important physiological mechanisms, such as excitatory transmission, neuronal migration and memory formation. a peculiar feature of nmda receptors is the absolute requirement of l-glutamic acid and glycine for the opening of the channel. noteworthy, these two aminoacids reciprocally modulate binding at their respective recognition sites. aim of this work was to study nmda receptor glycine/glutamate interactions in rat and human brain. binding of the nmda antagonist [ 3 h]cgp39653 to rat cerebral cortical membranes was inhibited by glycine. the overall effect of glycine consisted in a decrease of [ 3 h]cgp39653 affinity, with a parallel increase of the receptor affinity for glutamate. the glycine antagonist gv150526a competitively reversed glycine inhibition, proving that the modulation was via the glycine binding site. [ 3 h]cgp39653 binding to rat brain sections revealed the existence of regionally distinct nmda receptor subtypes with difference glycine/glutamate interactions. in most regions of the human brain nmda receptors presented the same allosteric modulation of [ 3 h]cgp39653 binding, as revealed by large section autoradiography technique. nevertheless, detection of any regional variation was not possible, probably due to the high intersubject variability. the effect of long-term high k ϩ -treatment on neuronal survival, cellular maturation, nmda receptor (nr) splice variant expression, and receptor function was investigated in primary cultures of rat cortical neurones. long-term incubation (up to 15 days) with 25 mm k ϩ significantly increased neuronal survival and induced multiple morphological changes associated with promoted cellular maturation. cultures grown in medium containing 25 mm k ϩ also exhibited multiple changes in nr1 splice variant expression according to rt-pcr studies performed with primer pairs flanking the alternatively spliced regions, in order to estimate the ratios of the corresponding 3ј and 5ј splice variants. nr1-1 and nr1-3 (each containing exon 21) were decreased, whereas nr1-2 and nr1-4 (each lacking exon 21) were increased, accordingly. the predominant expression of nr1-b was further increased. after administration of ttx, each of the k ϩ -induced changes on mrna expression was virtually abolished. in voltage-clamp recordings (holding potential: ϫ70 mv), nmda induced inward currents in a concentration-dependent manner with a maximum effect of ϫ745 pa under control conditions. neurones treated with 25 mm k ϩ showed a significantly diminished response to nmda (max. response: ϫ368 pa). in conclusion, the present data indicate that a sustained increase in neuronal activity induces adaptive changes in nr1 splice variant expression and a decrease in receptor function. thus, alternative splicing associated with a diminished receptorcytoskeletal linkage may be important compensatory mechanism in preventing cellular damage due to long-term activation of excitatory nr. it seems conceivable that this mechanism contributes to the promoting effects of 25 mm k ϩ on neuronal survival and maturation. (supported by bmbf grant 01gg9818/0) there is accumulating reports that kainate-induced seizures elicit expression of various heat-shock proteins (hsps) in the brain, such as hsp27, hsp32, and hsp70. however, no investigation has been carried out on changes in level of apg-2, a member of hsp 110 family, after excitatory amino acid-induced seizures. by means of an immunoblot assay, we determined the levels of hsp70 and apg-2 in discrete brain structures of mice after a single intraperitoneal injection of kainate or nmda. apg-2 level was significantly decreased in the frontal cortex, hippocampus, and striatum 3 days after kainate administration, while hsp70 level was increased in these regions following the administration. decreased level of apg-2 returned to the control levels in the three regions 10 days after kainate administration. no significant changes were observed in levels of both hsp70 and apg-2 in hypothalamus, midbrain, medulla-pons, and cerebellum of kainate-treated mice. by contrast, nmda administration did not significantly affect both levels in any of the regions examined. these results suggest that, unlike the case of hsp70, apg-2 expression could be temporarily down regulated by signals peculiar to kainate, but not by those peculiar to nmda, in murine telencephalon. high concentrations of glucagon-like peptide-1 (7-36) amide (glp-1) and its specific receptor (glp-1r) have been found in the rat hypothalamus. in this study the actions of glp-1 and its related peptides, exendin-4 (glp-1r agonist), exendin (9-39) (glp-1r antagonist) and glp-1(9-36)amide (major glp-1 metabolite) on levels of amino acids (glu, asp, gln, gly, tyr, trp, gaba) in the hypothalamus were investigated. 125 i-glp-1 binding in rat hypothalamic membranes was competed by the peptides in the following order of potency; glp-1 ͼ exending-4 ͼ exendin (9-39) ͼ glp-1(9-36)amide. intracerebroventricular (icv) glp-1 (4 nmoles) produced a statistically significant reduction in levels of all measured amino acids compared with saline injected controls, whereas 4 nmoles of exendin (9-39) was ineffective. exendin-4 produced a statistically significant reduction in the levels of trp, glu, and tyr. glp-1(9-36)amide showed a statistically significant increase in the level all the amino acids tested in this study. prior administration of exendin (9-39) or glp-1(9-36)amide blocked the effects of glp-1 on the levels of the amino acids. these data are consistent with exendin-4 being a glp-1r agonist and exendin (9-39) being a specific glp-1r antagonist. glp-1(9-36)amide, a primary metabolite of glp-1, appears to act as an endogenous antagonist at the glp-1r. department of biophysics, instituto de fisiología celular, universidad nacional autónoma de méxico, méxico city, méxico cholecystokinin (cck), a family of neuropeptides, seems to be involved in anxiety. evidence from several laboratories indicates that the ansiogenic effects of cck are mediated by cck b receptors. however it has been reported that cck a receptors have been found in brain and cck a receptor antagonists have ansiolytic properties. the aim of this work was to study whether or not cck a receptors are also involved in the modulation of anxiety. male rats were cannulated in the lateral ventricle and cck (9 fmol) and/or cck antagonists (900 fmol) were injected 7 days after surgery. anxiety was evaluated in the elevated plus-maze test and locomotion in an open-field test. ansiogenic effects were observed when cck b receptor agonists (cck8ns; cck4) or a mixed cck b and cck a receptor agonist (cck8s) were injected. in contrast, cck33, a cck a receptor agonist or cck 1-21 and cck 26-29 were uneffective. furthermore, the ansiogenic effects of cck8s were prevented by the previous (15 min) administration of l365,260 (cck b receptor antagonist) but not by devazepide (cck a receptor antagonist). no effects on locomotion were observed in any condition. these results indicate that cck a receptors are not involved in anxiety, as measured by the elevated plus-maze test. congenital conditions (i.e. neural tube defects: ntg) have a multifactorial aetiology. deficiencies in the folate and transsulfuration pathways have, in recent years, been positively linked to ntd and other dysmorhogenic syndromes. efficient one-carbon metabolism is crucial for the synthesis of dna precursors, the remethylation of homocysteine and biomethylation of dna. more than 80% of the one-carbon units that flow through the metabolic system in mammals and birds are derived from l-serine and glycine, the natural substrates for shmt. the mitochondrial glycine cleavage enzyme system (gces) can potentially compete with shmt for tetrahydrofolate (thf) in the generation of the methylenetetrahydrofolate pool. valproate (depakene, epilim), an anti-epileptic agent, appears to be strongly associated with hyperhomocysteinemia, several other induced metabolic conditions, the inhibition of the gces and an increased incidence of ntd in epileptic women of child-bearing age. the exact mechanisms of valproate-induced ntd are not yet clear. we investigated the association of the teratogenic properties of valproate with the inhibition of shmt and/or the gces in developing embryos. chicken embryos were treated with sodium valproate (vpa) and pregnant female mice (c57bl) received intraperitoneal injections of vpa, during the critical period of embryonic neural tube development. control embryos were treated with sterilised saline solution. harvested embryos were subsequently investigated for congenital abnormalities and hepatic shmt and gces activities quantified with radiometric assays. the effect of vpa on hepatic dna synthesis was monitored ( 3 h-thymidine incorporation into embryonic dna) and the dna-methylation status determined (dna n 5 -methylcytosine levels). dose-responsive incidences of ntd were observed in vpa treated embryos. very few defects occurred in control embryos. shmt and gces appeared to be inhibited in liver extracts of vpa-treated embryos. hepatic dna synthesis was significantly compromised and 5-mc levels were altered in vpa-treated embryos. the inhibition of either shmt and/or gces activities appeared to be associated with valproateinduced ntd in the chicken and mouse embryo models. the primary mechanism of this effect can probably be ascribed to a restriction in the flow of one-carbon units through the metabolic system, decreased synthesis of dna precursors and alterations in the methylation status of dna. department of neuroscience, university of cagliari, italy ethanol is long known to cause dose-related biphasic effects and we recently found that ethanol bidirectionally affects also working memory. the euphoriant and excitatory effects produced at low doses are associated with the rewarding action of ethanol and are thought to be mediated by the activation of the mesolimbic dopamine (da) system. however, ethanol monophasically stimulates mesolimbic da release in the nucleus accumbens, even at doses that cause hypnosis and coma. in contrast, ethanol biphasically modulates mesocortical da release in the prefrontal cortex (pfc). the changes in da release induced by ethanol are time locked with corresponding changes in extracellular glutamate levels. these biphasic effects of ethanol on pfc da and glutamate are matched by biphasic changes in the performance in a spatial delayed alternation task -a working memory test that is sensitive to proper function of the pfc -suggesting a link between da and glutamate transmission in the cognitive effects of ethanol. focal application in the pfc of the competitive ampa/kainate receptor antagonist cnqx suppresses both da release and the improvement of working memory induced by low doses of ethanol. these results suggest that ethanol may increase da transmission in the pfc and enhance working memory functions by increasing the release of glutamate, thereby stimulating non-nmda glutamate receptors. the enhancing effect on working memory by low, excitatory doses of ethanol may be perceived as rewarding and could constitute an important neurobiological mechanism for excessive ethanol drinking. physiology department, faculty of medicine, al-quds university, jerusalem, palestine glutamate and asparate are considered as the main excitatory neurotransmitters in brain and spinal cord, in addition to their role in energy metabolism, synthesis of proteins and detoxification of ammonia. glutamate and aspartate are centrally involved in basic mechanisms generating epileptic seizures and in epileptogenesis. stimulated release of glutamate and aspartate was detected in vivo and in vitro following neuronal depolarization. photic stimuli has increased glutamate release from visual cortex, and afferent brachial stimulation has increased the endogeneous release of glutamate from contra-lateral sensorimotor cortex compared to ipsi-lateral side. similar results were achieved after local application of tityustoxin or veratridine to the sensorimotor cortex. implantation of cobalt powder over the right sensorimotor cortex of rats produced an epileptogenic lesions characterized by contra-lateral fore and hind limb jerks and an increase in the frequency of eeg spikes. the jerks started after 6 days with maximum myoclonic activity (15 jerks/min). the concentration of glutamate in the epileptogenic focus was decreased significantly by 29% (p ͻ 0.01) compared to the non-epileptogenic area on the left sensorimotor cortex, which was dissected but not treated with cobalt. part of the decrease in glutamate could be related to the enhancement of in-vivo release from the epileptogenic lesion to the extra-cellular fluid. kindling is the best model for studying the development of the epileptic focus (epileptogenesis), it could be achieved by repeated intra-cerebral micro-injection of glutamate (1.5 µ mol), aspartate (0.75 µ mol) or nmda (2-4 n mol), or repeated electrical stimulations of specific brain regions. in addition, glutamate antagonists particularly those specifically acting on the nmda receptor type e.g. 2-amino-5-phosphonovaleric acid (ap5) and 2-amino-7-phosphonopheptanoic acid (ap7) have been found to inhibit seizures in epileptic animals and inhibit the development of electrically kindled epilepsy. pre-synaptic glutamate receptor agonists like (1s, 3s)-acpd the agonist of group ii, and l-ap 4 the agonist of group iii receptors has reduced ca ϩϩ uptake and glutamate release, thus it has inhibited epileptogenesis by preventing the increase in both seizure score and after-discharge duration. injection into fully kindled animals has produced an anti-epileptic effect by reducing the mean seizure score and by increasing the mean generalized seizure thresholds. this results suggest the mechanism by which pre-synaptically active glutamate receptor agonists block the development of the chronically epileptic state induced by electrical kinding, and indicate that their anticonvulsive activity is due to inhibition of pre-synaptic glutamate and/or asparate release following blockade of pre-synaptic ca ϩϩ entry. testing the changes in glutamate release from hyperactive brain tissues, and the effect of different glutamate agonists and antagonists, supports the role of glutamate in initiating the process of epileptogenesis, and contributes in developing new anti-epileptic agents. (this project was supported by a grant from alexo) the functional roles of cl(ϫ) and divalent cations in the na(ϩ)/cl(ϫ)/gaba cotransport were examined in xenopus oocytes expressing the human gat-1 (hgat-1) gaba transporter cdna. our results showed that cl(ϫ) was not absolutely required for na(ϩ)/gaba transport via the hgat-1 (loo et al., j biol. chem. 275:37414-37422, 2000) . the cl(ϫ) interacted with the transporter to modulate the binding of external na(ϩ). although hgat-1 transported cl(ϫ) across the membrane with a stoichiometry of 2na(ϩ) : 1cl(ϫ) : 1gaba, the transported cl(ϫ) did not contribute to the net charge translocated across the membrane, suggesting a cl(ϫ)/cl(ϫ) exchange mechanism during the gaba transport cycle. the gaba transport via the hgat-1 is also modulated by divalent cations. the uptake of [3h]-gaba was inhibited significantly when both ca(2ϩ) and mg(2ϩ) were removed from the uptake buffer. several divalent cations tested were individually able to sustain the gaba uptake. in contrast to uptake, the gaba efflux was enhanced significantly upon removal of both ca(2ϩ) and mg(2ϩ) from the efflux buffer. the gaba transporter inhibitor skf89976a blocked the enhanced efflux, suggesting that the hgat-1 operated faster in the reverse mode in the absence of external divalent cations. these results suggest a regulatory role for the divalent cations in gaba transport. merck sharp & dohme, neuroscience research centre, terlings park, harlow, essex, u.k. the role of alpha5 containing gaba a receptors in hippocampal synaptic function has been investigated using pharmacological and electrophysiological techniques, as well as following disruption of the alpha5 subunit gene in knockout mice (ko). in the ca1 region of the hippocampus the induction of long-term potentiation (ltp) is powerfully regulated by gaba mediated synaptic currents (ipscs). agents that inhibit gaba-mediated transmission potentiate ltp induction, whereas allosteric agonists such as benzodiazepine-site agonists which slow the decay kinetics of ipscs suppress ltp induction. in alpha5 ko mice paired pulse facilitation of the amplitude of excitatory synaptic potentials is selectively enhanced in the ca1 region but not dentate gyrus. likewise, the frequency and rise time of spontaneous ipscs were similar in wt and ko slices. however their amplitude was significantly smaller in ko mice. furthermore, a significantly greater proportion of ipscs were best fitted to a mono exponential function in ko mice compared to wt animals. thus alpha5 containing gaba a receptors contribute to functional postsynaptic receptors on ca1 pyramidal cells in the hippocampus and modulate a postsynaptic component of synaptic facilitation. pharmacological research institute, volgograd medical academy, volgograd, russia the purpose of the study is to investigate effect of phenil (karphedon, mephebut, gammoxin) and circle (pyracetam) gaba derivatives on reproductive function of stressed male rats. the adult male rats were stressed by immobilization exposure (2 hours) twice in week during 6 weeks. four from five groups of stressed males were given substances (daily) at doses: karphedon -50 mg/kg, mephebut -10 mg/kg, gammoxin -40 mg/kg, pyracetam -200 mg/kg. the treated males were mated with intact females during 12 days. after the mate the treated males and more in 10 days all the mated females were sacrificed and investigated. analysis of our data indicates that the time of spermatozoa motion and epididymal sperm counts were decreased 73.2% (p յ 0.05) and 49.1% (p յ 0.05) respectively when compared with their intact controls. gaba derivatives have a softening effect on functional parameters of spermatozoa stressed males. karphedon and pyracetam increased the time of motion spermatozoa 86.3% (p յ 0.05), karphedon and mephebut drew near sperm counts to intact control level. the result of mate show that pregnancy rate was increased (p յ 0.05) by stress exposure and pregnancy rate of females mated with gaba stressed males was some more (p ն 0.05) than that of intact controls. the general embryonic morality was increased twice by stress and so the number of embryos was reduced 48.8%. the gaba derivatives exposure to stressed male rats reduced the embryonic mortality of their posterity and increased the number of embryos to intact control level. our findings demonstrate that gaba derivatives administration has a protective effect on reproductive function of stressed male. transmission on the brain. the realization that glutamatergic pathways are involved in such diverse processes in epilepsy, ischemic brain damage and parkinsons' disease, is of a great practical interest. there are at least three functional classes of ionotropic glutamate receptors: n-methyl-d-aspartate (nmda), α-amino-3-hydroxy-5 methyl-4-isoxazolepropionic acid (ampa) and kainate (ka). other central neurotransmitter systems are under nmda influence. some data point on neuroprotective action of nmda antagonist on nigrostriatal pathway. in the present study female wistar rats were exposed during pregnancy with daily injected mk-801 (dizocilpine) 0.5 mg/kg sc. control rats received tap water only. behaviour of 3 month old male offsprings was investigated by several psychopharmacological methods. oral activity, yawning, locomotor activity, stereotypy and catalepsy were recorded following respective central dopamine receptors agonists and antagonists administration (skf 38393, quinpirole, apomorphine, haloperidol). our results indicate that mk-801 applied during pregnancy modulate reactivity of the central dopamine receptors in adult offspring rats. [ the development of mammalian ingestive behavior is characterized by a transition from suckling to chewing, two distinct motor behaviors. we hypothesize that this transition is accompanied by changes in brainstem circuitry underlying these movements. since glutamatergic neurotransmission is critical for the proper functioning of brainstem circuitry responsible for mastication, we investigated the development of glutamate receptors in trigeminal motoneurons (mo5) and mesencephalic trigeminal neurons (me5); neurons comprising the circuitry responsible for jaw movements. we conducted a series of receptor immunohistochemistry experiments that characterized the expression of iontotropic and metabotropic glutamate receptors (mglurs) during early postnatal development. the functional roles of nmda, ampa and mglurs in neonatal mo5 were investigated using in vitro electrophysiological experiments. results demonstrated that the spatial and temporal expression of ampa, nmda and group i and ii mglurs are developmentally regulated within and between mo5 and me5 during early development. electrophysiological data demonstrate that mglurs function pre-and postsynaptically to modulate synaptic transmission between trigeminal premotoneurons and mo5. furthermore, nmda induced bursting is developmentally regulated and coincident with the transition from suckling to chewing behaviors. our studies suggest that the transition from suckling to chewing is accompanied by changes in the composition and function of glutamate receptors. fetal life in down syndrome starts with normal neuronal density but impaired dendritic spines and synaptosomal structure r. weitzdoerfer 1 , m. dierssen 2 , m. fountoulakis 3 , and g. lubec 1 1 department of pediatrics, university of vienna, austria information on fetal brain in down syndrome (ds) is limited and there are only few histological, mainly anecdotal reports and no systematic study on the wiring of the brain in early prenatal life exist. histological methods are also hampered by inherent problems of morphometry of neuronal structures. it was therefore the aim of the study to evaluate neuronal loss, synaptic structures and dendritic spines in the fetus with down syndrome as compared to controls by biochemical measurements. 2 dimensional electrophoresis with subsequent mass spectroscopical identification of spots and their quantification with specific software was selected. this technique identifies proteins unambiguously and concomitantly on the same gel. fetal cortex samples were taken at autopsy with low postmortem time, homogenized and neuron specific enolase (nse) determined as a marker for neuronal density, the synaptosomal associated proteins alpha snap [soluble n-ethylmaleimidesensitive fusion (nsf) attachment protein], beta snap, snap 25 and the channel associated protein of synapse 110 (chapsyn 110) as markers for synaptosomal structures and drebrin (drb) as marker for dendritic spines. nse, chapsyn 110 and beta snap were comparable in the control fetus panel and in down syndrome fetuses. drebrin was significantly and remarkably reduced and not even detectable in several down syndrome brain samples. quantification of snap 25 revealed significantly reduced values in ds cortex and alpha snap was only present in half of the ds individuals. we conclude that at the time point of about 19 weeks of gestation (early second trimester) no neuronal loss can be detected but drebrin, a marker for dendritic spines and synaptosomal associated proteins alpha snap and snap 25 were significantly reduced indicating impaired synaptogenesis. early dendritic deterioration maybe leading to the degeneration of the dendritic tree and arborization, which is a hallmark of down syndrome from infancy. pathfinding of growing axons to reach their target during brain development is a subtle process needed to build up contacts between neurons. abnormalities in brain development in down syndrome (ds) are described in a couple of morphological reports but the molecular mechanisms underlying abnormal wiring in fetal ds brain are not yet elucidated. we therefore performed a study using the proteomic approach to show differences in protein levels involved in the guidance of axons between control and ds brain in early prenatal life. proteins obtained from autopsy of human fetal abortus were applied on 2-dimensional gel, identified and quantified. we quantified 5 members of the semaphorin/collapsin family, the dihydropyrimidinase related proteins 1-4 and the collapsin response mediator protein-5 (crmp-5) in 8 ds and 7 control cortex samples. drp-1 and crmp-5 levels were comparable in the control and ds samples. evaluation of drp-2, drp-3 and drp-4 revealed significantly decreased levels of 2 of the 15 spots assigned to drp-2 and increased levels of one spot assigned to drp-3 and increased drp-4 in ds brain. we conclude that as early as from the 19 th week of gestation pathfinding cues of the outgrowing axons are impaired in ds. these findings may help to elucidate mechanisms leading to abnormalities in neural migration of ds brain. inflammatory processes play an important role in the degeneration of basal forebrain cholinergic cells alzheimer's disease. the proinflammagen lipopolysaccharide (lps) was infused chronically into the basal forebrain of young rats. we then determined whether the administration of two novel nonsteroidal anti-inflammatory drugs or a pancaspase synthesis inhibitor, zvad, could provide neuroprotection from the cytotoxic effects of the neuroinflammation. we also determined whether the administration of the non-competitive n-methyl-d-aspartate (nmda) receptor antagonist, memantine, could provide neuroprotection from the cytotoxic effects of the neuroinflammation. chronic lps infusions decreased choline acetyltransferase activity and increased the number of activated microglia within the basal forebrain. caspases 3, 8 and 9 activity was increased in ventral caudate/putamen. non-steroidal antiinflammatory drug therapy attenuated the toxicity of the inflammation upon cholinergic cells and reduced caspases 3, 8, and 9 activity in the caudate/putamen. zvad significantly decreased the levels of caspases 3, 8 and 9 but did not provide neuroprotection for cholinergic neurons. memantine significantly attenuated the cytotoxic effects of chronic inflammation upon cholinergic cells. these results suggest that prostaglandins contribute to the degeneration of forebrain cholinergic neurons in alzheimer's disease and that the cytotoxic effects of prostaglandins occur upstream to nmda receptor activation. intracranial administration of n-methyl-d-aspartate (nmda) receptor antagonists block learning of classical and avoidance conditioning in goldfish. studies with goldfish have shown that nmda receptors are mostly dense in the telencephalon and telencephalon ablation impairs avoidance learning. the present study investigated amnestic effects of microinjection of nmda receptor antagonist ap5 to the goldfish telencephalon in avoidance conditioning. in experiment 1, fish received no injection or microinjections of saline or various doses of ap5 to their telencephalon 20 minutes before three semiweekly training sessions. fish were tested without injec-tions in session 4. a one-way anova with multiple comparisons on the test scores showed that ap5 produced anterograde amnesia in a dose-dependent manner. in experiment 2, fish received several training sessions and a microinjection of various doses of ap5 20 minutes before testing. the test scores showed that ap5 did not decrease avoidance responses, suggesting that microinjection of ap5 did not impair performance processes. in experiment 3, fish received microinjections of ap5 or saline to their telencephalon immediately following three semiweekly training sessions and were tested without injections in session 4. a one-way anova on the test scores showed that ap5 did not produce retrograde amnesia. (supported by gvsu grant-in-aid.) tryptophan modulates striatal serotonergic activity relative to fatigue t. yamamoto 1 and e. a. newsholme 2 1 health science laboratory, tezukayama university, nara, japan 2 department of biochemistry, university of oxford, u.k. we have been reported that mechanism of fatigue in the brain relates to enhanced extracellular tryptophan and serotonergic function. brain concentration of tryptophan is not only dependent on the change of tryptophan which originates from the centarl nervous system, but also enhance tryptophan entering the brain from the blood-brain barrier and peripheral circulating tryptophan which is a trigger. supplementation of ltryptophan (2 um) into the incubation medium with the synaptosomal striatum causes tryptophan to the extrasynaptosomal release by high kϩ stimulation. injecting l-tryptophan (1 mm/ 30 min) into the left striatum by microdialysis method can induce early fatigue for running time of rats. on the other hand, tryptophan deficiency rats (body weight average 200 g) were made by tryptophan free feeding for 2 weeks, and the rat's running time increased (ͼ100 min difference). these results suggests that tryptophan is a potent active substance for fatigue in the brain. the active zone may be presynaptic terminal and the tryptophan itself may be releasing neuromodulators. (we appreciate that tryptophan free diet was provided by ajinomoto co., inc., japan.) our recent studies on the distribution of free d-serine, together with the d-serine action on the glycine site of the nmda type glutamate receptor, suggest that the d-serine can be an endogenous modulator of the nmda receptor. to explore the possible removal systems for brain d-serine signaling, we have evaluated the uptake of [3h]d-serine into the synaptosomal p2 fraction from the rat cerebral cortex. the cortical p2 fraction was able to accumulate [3h]d-serine in a temperatureand ph-dependent and saturable manner. the kinetic analysis indicates that cortical d-serine transport occurs by an apparent single-component system with km value of 283 µm and a vmax value of 207 pmol/mg protein/min. depletion of na ϩ and cl ϫ ions remarkably decreased d-serine uptake into the cortical p2 fraction. the pharmacological profile of the inhibition of dserine uptake by various amino acids was different from those of glycine uptake system and other amino acid transporters reported. d-serine uptake activity was preferentially observed in the brain tissues such as cerebral cortex and cerebellum to the peripheral tissues. the present data support the view that the endogenous d-serine is taken up mainly through a carriermediated transport system to regulate the extracellular concentration in the mammalian brain. a. bocheva et al. the mammalian brain contains all the urea cycle intermediates, whereas enzymes participating in the conversion of lornithine (l-orn) into l-citrulline (l-cit) are absent, resulting in an incomplete urea cycle. the discovery of nitric oxide (no) synthase that catalyses the formation of no and l-citrulline as a co-product from l-arginine (l-arg) in the brain has indicated an additional pathway for l-arg metabolism. l-canavanine (l-cav), is a potent antimetabolite and structural analog of larginine, produced by legumes such as the jack bean, canavalia ensiformis. l-canaline (l-can) is a potent inhibitor of ornithine aminotransferase. our previous results indicated that l-cav, l-cit, l-arg, and l-orn exerted an antinociceptive effect, whereas l-canaline induced hyperalgesia in rat. l-canavanine exert stronger antinociceptive effect than l-arginine, l-ornithine and l-citrulline. the aim of the present study was to investigate are d-arg, l-cav and naloxone reversed the analdesic effects of l-ornithine, l-citrulline and l-arginine. the experiments were carried out on male wistar rats. the changes in the mechanical nociceptive threshold of the rats were measured by the radall-selitto paw pressure test using and analgesimeter (ugo basile). the amino acids were applied intracerebroventricularly (i.c.v.) at a dose 20 µg/rat. the present results shown that d-arg, l-cav and naloxone reversed antinociception. the regulation of lysine metabolism in cereal crops r. a. azevedo 1 , p. j. lea 2 , s. a. gaziola 1 , a. p. pellegrino 1 , and s. m. g. molina 1 1 departamento de genética, escola superior de agricultura luiz de queiroz, universidade de são paulo, brazil 2 department of biological sciences, university of lancaster, u.k. a major nutritional drawback of cereal seeds is a deficiency in some amino acids, in particular lysine. biochemical, molecular and genetic studies have considerably increased our knowledge concerning the regulation of the aspartate pathway, by which lysine is synthesized. among the enzymes involved in lysine metabolism, aspartate kinase (ak) and dihydrodipicolinate synthase (dhdps) control the regulation of lysine biosynthesis, whereas lysine: 2-oxoglutarate reductase (lor) and saccharopine dehydrogenase (sdh), have been shown to play a key role in the breakdown of lysine. in general, lysine overproduction can be obtained by altering the sensitivity of dhdps to lysine, but accumulation of this amino acid in cereal seeds requires further manipulation of lor and/or sdh. this suggestion is strongly supported by five main points: (1) cereal mutant or transgenic plants do not exhibit any significant accumulation of lysine in seeds, but only in other tissues. (2) the enzymes of lysine degradation, lor and sdh, are endosperm specific in cereals only. (3) the opaque-2 mutant, which exhibits higher concentration of soluble lysine and protein lysine in the seed, contains several-fold lower lor and 2-fold lower sdh activity when compared to the wild-type maize. this reduction in activity in the opaque-2 mutant is due to a reduced protein lor-sdh concentration by reduction of the zlkrsdh gene transcript. furthermore, the opaque-2 maize gene has been shown to regulate ak and lor activity. (4) intermediates of lysine catabolism accumulated in the seeds of soybean and canola lysine overproducing plants, suggesting the presence of reduced lor and/or sdh activities. (5) among cereals and although still below the recommend values by fao, rice exhibits the higher concentration of lysine, but lor and sdh are present in much lower activities. also, in phaseolus vulgaris, lor and sdh activities were shown to be around 10fold lower then in maize endosperm. the regulation of the lor activity is complex and involves a calcium dependent phosphorylation/dephosphorylation mechanism. it remains to be seen whether this latter mechanism can be controlled, so as to allow the production of more crop plants that contain elevated concentrations of lysine in the seed. the genetic progress for nue can be accelerated with the use of secondary traits that possess high inheritance and correlation with productivity. several traits have been studied such as chlorophyll concentration, plant height, leaf senescence, anthesis-silking interval, kernel number, activities of enzymes of n assimilation and loci of quantitative traits for assisted selection. (we are grateful for financial support from fapesp, brazil and the british council.) (termed hyperaccumulators) that grow on metalliferous soils, are able to translocate cd from the roots and accumulate it in high concentrations in the shoots. cd may be detoxified in plants by combination with a family of sulphur rich peptides termed phytochelatins. cd has the capacity to inhibit a range of enzyme activities in plants, in particular those of the calvin cycle and chlorophyll biosynthesis. evidence that cd causes the production of reactive oxygen species (ros) has also been obtained. we have investigated the antioxidant responses of radish, soybean and sugarcane to cd treatment. seedlings were grown in increasing concentrations of cdcl 2 , ranging from 0.01-1 mm, for up to 96 h in a hydroponic system. analysis of cd uptake indicated that most of the cd accumulated in the roots, but some was also translocated and accumulated in the leaves. roots and leaves were analysed for catalase (cat), glutathione reductase (gr) and superoxide dismutase (sod) activities. gr activity increased considerably in the roots of all plant species tested after exposure to the metal, indicating a direct correlation with cd accumulation. cat activity also increased in roots but to a much lesser extent when compared to gr and also varied depending upon the plant species. the analysis of native page enzyme activity staining, revealed several sod isoenzymes in leaves of all plant species, however, only in radish was a clear increase in activity observed. the results suggest that in these plants, the activity of antioxidant enzymes responds to cd treatment. the main response may be via the activation of the ascorbate-glutathione cycle for the removal of hydrogen peroxide, or to ensure the availability of glutathione for the synthesis of cd-binding proteins. (we are grateful for financial support from fapesp, brazil and the british council.) all plant cells, tissues and organs provide the biosynthetic machinery and capacity to synthesise aliphatic polyamines. however, in physiological conditions only some organs and tissues synthesise polyamines, such as apical buds and sprouts, root apex, lateral buds of branches and secondary roots, as well as superficial layers of young stems and leaves, like epidermis, subepidermis and parenchyma cells. apical roots can also synthesise polyamines, but these activities in physiological conditions are lower than that of the shoots. this patterns recalls the one of auxins. polyamines are accumulated in high concentrations in storage organs, such as seeds, but not in tubers like helianthus tuberosus, potato or tuberised roots such as the carrot. also some fruit, e.g. oranges, contain high level of free polyamines, putrescine in particular. all other organs obtain polyamines through translocation via phloem tubes and xylem vessels. in plants, in addition to free polyamines, many polyamines are conjugated to hydroxycinnamic acids, the hydroxycinnamic amines, that only rarely represented outside the plant kingdom. this compounds are paticularly abundant in solanaceae family, where they can represent as much as 90% of the total polyamine pool, but they can be detected in different concentrations in many other families. the role of free and conjugated polyamines and their importance in food is discussed. drought, salinity or other environmental stressors promote the accumulation of free amino acids, amines and other organic n-metabolites with low molecular weight. in this contribution the influence of drought on the accumulation of amino acids, polyamines and trigonelline in growing barley plants and barley grains was examined. in comparison to non-stressed plants we obtained in stressed plants, exposed to drought before flowering, a higher concentration of proline (increase: 4-fold), n-trimethylglycine (2-fold), histidine (3-fold), tryptophane (1,7-fold), putrescine (1,4-fold), spermine (1,7-fold) and trigonelline (2-fold) in the dry matter of barley sprouts. in addition to this, drought caused an increase of the n-content in the plant biomass (35%) as a result of growth inhibition (34%). six weeks later the content of soluble n-metabolites and protein was analyzed in non-stressed and pre-stressed barley plants again. during this reproductive period of plant development all the test groups were cultivated under the same moisture conditions. the analysis of n-metabolites in the ripening grains showed, surprisingly an after-effect of the drought stress. for example, in grains of pre-stressed barley the concentrations of free proline, histidine, tryptophane and asxϩglx were threefold to fivefold higher than in grains of non-stressed barley. depending on the resistance of barley cultivars to drought the biochemical response was different: in plants with low resistance the increase of amino acids and amines was higher than in resistant cultivars. however, resistant cultivars have already high genuine concentrations of n-metabolities in non-stressed plants. by treatments with choline or 2-aminoethanol the stresspromoted accumulation of amino acids and trigonelline was diminished. consequently, different biochemical responses of cereals to drought result in changes of product quality and nitrogen use. our goal is to increase the lysine content in corn. we have used genetic engineering to increase lysine synthesis and to prevent metabolic breakdown of lysine. to increase synthesis we circumvented the normal feedback control of a key enzyme in the lysine biosynthetic pathway, dihydrodipicolinic acid synthase (dhdps). lysine-feedback-insensitive dhdps, encoded by the corynebacterium dapa gene, was expressed from seed-specific promoters in transformed corn seeds. expression of dhdps in the corn embryo, but not in the corn endosperm, resulted in a 20 to 30-fold increase in the accumulation of free lysine in the seeds and the total seed lysine content nearly doubled. lysine breakdown products have been observed in transgenic seeds that accumulate high levels of free lysine. we isolated a corn gene for the bifunctional enzyme lysine ketoglutarate reductase (lkr)/saccharopine dehydrogenase (sdh), which catalyzes the first two steps in lysine breakdown. knockout of lkr/sdh in corn by either mutation or genetic engineering results in a 10-fold increase in seed free lysine. combination of feedback-insensitive dhdps with knockout of lkr/sdh results in 2 to 3-fold higher levels of free lysine than dhdps alone. no adverse effects on seed or plant agronomic performance are associated with the high lysine trait. biotechnology center for agricultural and the environment and the plant science department, rutgers university, new brunswick, new jersey, u.s.a. 5ј-adenylylsulfate (aps) reductase catalyzes a key reaction in the plant sulfate assimilation pathway leasing to the synthesis of cysteine and the antioxidant glutathione. in arabidopsis thaliana aps reductase is encoded by a family of 3 genes. in vitro studies revealed that the enzyme product derived from one of the aps reductase genes (apr1) is activated by oxidation, probably through the formation of a disulfide bond. redox titrations show that the regulation site has a midpoint potential of ϫ327 mv at ph 8.5 and involves a 2-electron redox reaction. exposure of a variety of plants to ozone induces a rapid increase in aps reductase activity that correlates with the oxidation of the glutathione pool and is followed by an increase in free cysteine and total glutathione. during the response to ozone the level of immuno-detectable aps reductase enzyme does not increase. treatment of a. thaliana seedlings with oxidized glutathione or paraquat induces aps reductase activity even when transcription or translation is blocked with inhibitors. the results suggest that a post-translational mechanism controls aps reductase. a model is proposed whereby redox regulation of aps reductase provides a rapidly responding, self-regulating mechanism to control the glutathione synthesis necessary to combat oxidative stress. in aspergillus nidulans the structural genes coding for nitrate reductase (niad) and nitrite reductase (niia), share a common promotor region of 1,200 bp. we have previously characterized in vitro and in vivo the physiologically relevant cisacting elements for the two synergistically acting transcriptional activators, nira and area. we have further shown that area is constitutively bound to a central cluster of four gata sites and is directly involved in opening the chromatin structure over the promoter region and thus making additional cis-acting binding sites accesible. here we show that the asymmetric mode of nira-dna interaction determined in vitro is also found in vivo. binding of the nira transactivator is not constitutive as in other binuclear c 6 -zn ϩϩ -cluster proteins but depends on nitrate induction and additionally, on the presence of a wild type area allele. dissecting the role of area further, we found that it is required for intracellular nitrate accumulation and therefore could indirectly excert its effect on nira via inducer exclusion. but in a strain accumulating nitrate independently of area nira binding and chromatin rearrangement is not triggered by nitrate in the absence of area. v. nikiforova 1 , m. zeh 1 , o. kreft 1 , s. maimann 1 , h. hesse 2 , and r. höfgen 1 1 max-planck-institut für molekulare pflanzenphysiologie, potsdam, and 2 institut für biologie, angewandte genetik, freie universität berlin, germany higher plants, being a source of reduced sulfur for animal nutrition, assimilate inorganic sulfate into cysteine which is subsequently converted to methionine, another sulfur-containing amino acid. in order to investigate the possible regulatory points of the cysteine and methionine biosynthesis pathway a series of transgenic potato plants was engineered using clones encoding enzymes of the branched pathway from serine to cysteine as a pathway intermediate and from aspartate further on to methionine. increased cysteine levels were obtained in the leaves of serine acetyltransferase (sat) sense and cystathionine -lyase (cbl) antisense transformants. furthermore, glutathione levels were elevated in sat plants while downregulation of cbl was desastrous for plant growth, eventually. increased methionine levels were successfully obtained in potato by antisense inhibition of threonine synthase (ts). accumulation of free methionine was not only observed in source leaf tissues but as well in tubers. this enzyme competes with cystathionine gamma-synthase for the common substrate o-phosphohomoserine at the branchpoint between threonine and methionine synthesis, respectively. important control points of the biosynthesis of cysteine and methionine in potato, thus, turned out to be sat and ts, while further studies on overexpression of cystathionine gamma-synthase, cbl and ms did not reveal any substantial effect on potato methionine biosynthesis. dniepropetrovsk national university, board of biophysics and biochemistry, ukraine amino acids in root exudates of plants may be chelate agents as an alpha-amino acid can act like a bidentate ligand, forming a five-membered heterocyclic ring with suitable metal cations thus increasing mobility of metals. recently we have showed that application of growth regulators led to sharp increase of root exudative activity of some cultural (zea maize l.) and wild cereals (festuca rubra l., lollium perenne l.) during first days of germination. in this work we present results obtained in experiments with lollium perenne l., grown on sterile sand and on soils contaminated with great quantities of zn. detailed analysis of amino acid content of root exudates of several types of maize (hybrid, several lines, an opaque-2 mutant line) showed that the specie had more certain amino acids (cysteine, aspartic and glutamic acids and their amides, serine) in root exudates than cultural ones. these amino acids has more possibility for chelation due to existance of one more polar or ionogenic functional groop. seeds of lollium perenne l. were treated with growth regulater and planted on soils contaminated with salts of zink. it was shown that during 15 days of germination quantity of zn in primary leaves increased from 121,46 to 243,75% and decreased in soil: in upper layer from 95,74 to 85,07, midde layer from 95,83 to 82,04, lower layer from 85,72 to 72,74 mkg/kg correspondingly. thus, it was shown that stimulation of root exudative activity by pretreatment with a growyh regulator may be succesful in cleaning of soils and basicly this is a good method for phytoremediation. erenol exerted the strongest effect. exercise completely abolished the levels of cysteine in the atrial heart muscle. propranolol, isoproterenol, caffeine and pentylenetetrazol increased the ratio of cysteine to the total free amino acids in the atrial muscle, while physical stress and all cardioactive drugs tested increased this ratio in the ventricle muscle. disappearance of cysteine from the heart's atrial muscle after intensive exercise may be attributed to its utilization for atrial natriuretic factor and/or for endothelin synthesis, during stress. on the other hand it seems that hypoxia and isoproterenol are strong stimulants of no production, and consequently decrease the tissue levels of l-arginine, which is the major endogenous donor of no acting as the endothelin antagonist. measurement of serum levels of vitamin b12 is a screening test for detection of deficiency of this vitamin but low levels do not always indicate a deficiency of the vitamin. measurements of serum homocysteine and methylmalonic acid (mma) are used to confirm this deficiency because two enzymes involved in their metabolism have been shown to require vitamin b12, but these results can also be inaccurate. vitamin b12 deficient white cells exhibit ultrascopic nuclear appenages which have been shown to contain dna; this finding could possibly be used as another confirmatory test of vitamin b12 deficiency. twenty-seven patients (mean age -76.6 years) with low serum b12 were studied by electron microscopic determination of the percent of neutrophils exhibiting these appendages and routine clinical parameters. only one patient did not have nuclear appendages; the others had a range of 0.8%-17.6% of neutrophils examined. there was a significant correlation of homocysteine (r ϭ .46, p ͻ .05) and mma (r ϭ .53, p ͻ .01) with serum b12 levels but no correlation of appendage number (r ϭ .18) with serum b12. there was no correlation of appendage number with homocysteine (r ϭ .25) or mma (r ϭ .04). these results suggest that b12-deficient white cell nuclear appendages do not measure the same metabolic pathways as homocysteine and methylmalonic acid and may be useful in confirmation of vitamin b12 deficiency. further extensive clinical evalution would be necessary to explore this possibility. the hypothesis: "l-theanine has relaxing effects of central nervous system of human beings", was verified by electroencephalographical methods. methods: 14 male, healthy sport-students, free of drugs or stimulants, participated weekly in a cross-over study. after exhaustive bicycle-ergometer test as an individual, reliable, stress model, the subjects recovered by lying in a segregated shaded room. three testdrinks with different l-theanine content (d1 ϭ placebo, d2 ϭ 50 mg, d3 ϭ 200 mg) were given in a randomised, double-blind order. all test-conditions were standardized strictly. eeg-recordings (closed eyes) were carried out (m1 ϭ 3 min. after stress/before testdrink, m2 ϭ 30 min.-, m3 ϭ 45 min.-, m4 ϭ 60 min.-, m5 ϭ 120 min. after testdrink) with the cateem ® system. absolute and relative eeg-spectralpower were examined. results: significant reductions in all frequencies (exception theta-power) were found in early recovery, being not significant influenced by testdrinks. qualitative different behavior trends were found in frontal-, central-, occipital-regions with increased alpha1, theta (frontal) and decreasing beta1 relative-power earlier in recovery with d3. these findings were related to relaxing effects. after ingestion of l-theanine alpha2-, beta1-power at occipital regions decreased faster (m2) to placebo recovery levels (m3/m4). thus it may be concluded that l-theanine has no pharmaceutical effect on the down regulation system but supports the physiological mechanisms during recovery after physical stress in human brain. arginine and cysteine in muscle cytosol of rats' heart after exercise, hypoxia or challenge with six selected cardioactive drugs r. brus 1 , j. gabryś 2 , j. konecki 2 , and j. shani 3 1 department of pharmacology and 2 department of histology and embriology, medical university of silesia, zabrze, poland 3 department of pharmacology, the hebrew university school of pharmacy, jerusalem, israel levels of the amino acid l-arginine (a major endogenous donor of nitric oxide-no), cysteine (sulfur-containing amino acid, important for atriopeptins and endothelins synthesis), and of total free amino acids, were assayed by gas-liquid chromatography in cytosols of rats' atrial and ventricular muscle cardiomyocytes. the tissues were assayed after the rats had been exposed to either exercise (swimming), hypoxia or one of six cardioactive drugs such as propranolol, digoxin, pentylenetetrazol, reserpine, isoproterenol and caffeine. physical stress and the examined drugs significantly reduced the total amount of cytosolic free amino acids in both cardiac muscles. in the cytosol of the heart atrial muscle, reserpine, propranolol and pentylenetetrazol increased the relative content of l-arginine, while hypoxia and digoxin decreased it. in the cytosol of the ventricular heart muscle, hypoxia and all six drugs used, decreased the relative levels of l-arginine. hypoxia and isoprot-addition of somatostatin-14 or of some of its analogs was found to cause a selective inhibition, up to 50%, of the uptake of large neutral amino acids by isolated brain microvessels. although the luminal and abluminal sides of brain endothelial cells are both capable of taking up large neutral amino acids, only the uptake from the abluminal side was apparently inhibited by somatostatin. the involvement of a type-2 somatostatin receptor was suggested by assays with a series of receptorspecific somatostatin agonists, and was confirmed by the inhibition release caused by a specific type-2 receptor antagonist. a type-2 specific mrna was indeed shown to be present both in bovine brain microvessels ex vivo and in primary cultures of endothelial cells from rat brain microvessels. hemorphins represent a bioactive peptide class which contents between 4 and 10 amino acids and generated from the proteolysis of an hemoglobin "strategic zone". many activities have been related to hemorphins such as in vitro anti tumour effect, analgesia effects in vivo, and a potential role in the renin angiotensin system (ras). as far as their activity towards the ras is concerned, it was demonstrated that they could inhibit angiotensin converting enzyme (ace) and aminopeptidase n activity. so they could reduce angiotensin ii formation and angiotensin iv degradation. moreover some hemorphins, lvv-hemorphin-7 and vvhemorphin-7, could behave like angiotensin iv receptor binding competitor. further it could be interesting to study the angiotensin iv potentiality to interact with ace. inhibition studies showed that it was possible that angiotensin iv could behave like a competitive inhibitor of ace. so some hemorphins could interact at different ras steps to inhibit ace. additionally to their inhibition of angiotensin i conversion, they could inhibit angiotensin iv degradation and consequently cause ace feedback inhibition. inhibition studies have been checked with ras natural substrate (angiotensin i) and confirmed that angiotensin iv, vv-hemorphin-7 and mainly lvv-hemorphin-7 could be natural ace inhibitors. so the hemorphins regulatory role in the ras appears to be more and more probable. the role of administration of each of methionine and finastride on the testicular function of both normal and prostate precancerous old male rats was investigated. for normal animals, neither methionine nor finastride has exerted any significant change in the hormonal profile after teatment for 20 days. however methionine alone could exert a significant change in both testosterone and prostatic specific antigen {psa} levels after treatment for 40 days. on the other hand, both methionine and finasteride significantly increased the levels of testosterone and androstenedione, whileas markedly reduced the levels of dihydrotestosterone and prostatic specific antigen {psa} after treatment of prostate precancerous old male rats for a period of 20 days. noteworthy, continuation of treatment for aperiod of 20 days realized marked improvement of hormonal profile of the prostate precancerous old male rats. several observations in our department point to some role of glycine in fatigue and exercise. 1) in the framework of a study on the involvement of one-carbon matabolism in patients suffering from a polymorphic episodic psychosis, amino acid loading tests with serine, glycine and alanine were performed. a few hours after the administration of glycine, approximately 40% of the patients reported overwhelming feelings of fatigue and/or showed vegetative symptoms. 2) in patients suffering from chronic fatigue syndrome, we found increased plasma levels of glycine in 20% of the female patients. moreover, 60-70% of these patients omplained about a distorted sensory perception of objects. 3) young soccer players were observed during a period of 10 months, while in the course of this period eight blood samples were taken for amino acid analysis. based on the number and severity of injuries this population was divided into injury-prone and not injury-prone soccer players. it was found that in injury-prone soccer players plasma glycine levels during the whole observation period were significantly lower than in subjects who were not injury-prone. the consequences of the above mentioned observations will be discussed. institute of sportsmedicine, university of paderborn, germany 50 percent of amino acids in green tea leaves are represented by l-theanine (5-n-ethylglutamine). previous rat experiments demonstrated effects of l-theanine to act on metabolism of neurotransmitters. it was therefore suggested that is causes the relaxing effects of green tea. to examine its influence as a component of a drink on the sympathetic nervous system after maximal physical exercise skin resistance measurements through electrosympathicography (esg) were used. after individual maximal exercise on a bicycle-ergometer testdrinks with different amounts of l-theanine (0, 50 and 200 mg) were administered to 14 healthy volunteers in a randomised cross-over double-blind distribution on a weekly base. esg was monitored before and immediately after exercise as well as 13, 30, 45, 60, 75 and 135 minutes after end of exercise. all testconditions were standardized strictly. a characteristic esgcourse with subsequent qualities could be shown: 1. decreasing skin resistances after exercise could be established in each volunteer. 2. esg-activation levels before exercise could not even be reached again after a period of regeneration of 2 1 / 4 hours. 3. maximal electrodermal activity did not appear immediately after exercise, but after 13 minutes. however, l-theanine could not significantly influence peripheral sympathetic electrodermal activity during the regeneration after maximal physical exercise. a. mero 1 and h. pitkänen 1,2 1 neuromuscular research center, department of biology of physical activity, university of jyväskylä, and 2 rehabilitation center of kankaanpää, finland essential amino acid leucine has many important roles in the body. therefore the purpose of the present study was to investigate if leucine supplementation has effects on serum amino acid profile and performance following training period or following single training sessions. all experiments were carried out in a randomized double blind cross-over procedure during a training season. thirty six adult male track and field power athletes served as subjects. in experiment 1 ten of them were given leucine (50 mg/kg body weight per day) as tablets. the concentration of leucine decreased significantly (20%) in the placebo group (p; n ϭ 10) during 5 weeks but not when leucine was taken. also total amino acids (taas) decreased strongly (19%) during 5 weeks when dally protein intake was 1.26 g/kg body weight. in experiment 2 the subjects (n ϭ 16) carried out a single strength training seasion (sts) and consumed a drink containing leucine 100 mg/kg body weight. following sts leucine in serum increased by 11% (ns) when leucine was taken but decreased strongly (30%) in p, in experiment 3 the subjects (n ϭ 12) underwent at 7 days interval two maximal anaerobic running exercise (mare) tests on treadmill (n ϫ 20s with a recovery of 100s between the runs) until exhaustion. the subjects consumed drinks containing leucine (200 mg/kg body weight) or placebo 50 min before the test runs. following mare the concentration of leucine strongly increased by 28% whereas isoleucine (25%) and valine (15%) strongly decreased with the supplementation but no changes occurred in p. there were no improvements in physical performance either in mare or in explosive strength (experiment 2) with leucine supplementation. the date suggest that leucine supplementation during a training period and before single training sessions prevents decreases in serum concentration of leucine and may have also effects on some other single amino acids. this may be beneficial during intensive training although improvements in performance were not observed in this study. since there are only limited data regarding effects of training period or training sessions on serum amino acid profile, the purpose of this study was to investigate serum amino acid changes following training period and following three different training sessions. the subjects consisted of 31 track and field adult male power athletes. in experiment 1 eleven of them performed a 5-week training period including a training sessions per week, which included sprint work, speed endurance work, endurance work, weight training, and jumps. significant decreases in the fasting concentrations of total amino acids (taas) (19%), branched chain amino acids (bcaas) (21%), essential amino acids (eaas) (19%) and leucine (20%) were observed following training with the daily protein intake of 1.26 g/kg body weight. in experiment 2 eleven subjects performed a short run session (srs) of 3 ϫ 4 ϫ 60 m with recoveries of 120 s and 360 s, and a long run session (lrs) of 20 s runs with recoveries of 100 s until exhaustion. there were no significant changes in taas following the sessions but bcaas decreased by 8% in srs and by 7% in lrs. leucine decreased by 10% following srs but only by 5% (ns) following lrs. the peak blood lactate concentrations after srs and lrs were 13.8 ϯ 1.9 mmol/l and 16.4 ϯ 1.3 mmol/l, respectively. in experiment 3 sixteen subjects carried out a strength training session (sts), which consisted of jumps and heavy resistance exercises (speed and maximum strength) during 90 minutes. the taas decreased significantly by 14%, bcaas by 24% and leucine by 30% following sts, while the peak blood lactate concentration was 2.2 ϯ 0.4 mmol/l. these data indicate that remarkable decreases occur in the concentration of amino acids during a training period with the daily protein intake of 1.26 g/kg body weight. the decreases in serum amino acids are more pronounced following a strength training session than following lactic anaerobic running sessions. glutamine acts as a multipurpose regulator of amino acid and peptide transport across the blood-brain barrier departments of cellular biotechnology and haematology and of biochemical sciences, university "la sapienza", rome, italy isolated brain microvessels, the in vitro equivalent of the blood-brain barrier, have distinct na ϩ -independent uptake systems for the uptake of large hydrophobic amino acids, of enkephalins and of deltorphins, as shown by the absence of reciprocal inhibition. both d-and l-glutamine were capable, if added to the extracellular buffer, of exerting a competitive inhibition on the uptake of all these substrates. a trans-stimulatory effect was instead induced, in all cases, by l-glutamine preloading of the microvessels -the d-stereoisomer being instead ineffective, probably because of only l-glutamine could be taken up, in a concentrative manner, by some na ϩ -dependent concentrative system(s). all the na ϩ -independent systems present in brain microvessels seem therefore to share some structural feature responsible for their common susceptibility to interference by l-glutamine. this amino acid, whose synthesis can take place in the astrocytes, in the pericytes and also in the endothelial cells of the microvessels, plays a critical role in regulating the movements of several different substrates across the blood-brain barrier. department of applied bioorganic chemistry, division of life science, graduate school of agricultural science, tohoku university, aoba-ku, sendai, japan isolation and structure analysis of two amino acids from bovine ligamentum nuchae elastin hydrolysates revealed the presence of pyridine cross-links in elastin. the structures of these amino acids were determined to have 3,4,5-and 2,3,5-trisubstituted pyridine skeletons both with three carboxylic acids and a mass of 396 (c 18 h 28 n 4 o 6 ), identified as 4-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3-carboxypropyl)pyridine and 2-(4-amino-4-carboxybutyl)-3,5-di-(3-amino-3carboxypropyl)-pyridine. we have named these pyridine cross-links, desmopyridine (desp) and isodesmopyridine (idp), respectively. structure analysis of these pyridine crosslinks implied that the formation of these cross-links involved the condensation reaction between ammonia and allysine. the elastin incubated with ammonium chloride showed desp and idp levels increased as the allysine content decreased. desp and idp were measured by hplc with uv detection and were found in a variety of bovine tissues. the desp/desmosine and idp/isodesmosine ratios in aorta elastin were higher than in other tissues. desp and idp contents in human aorta elastin were found to be gradually increased with age. the concentration of idp was significantly elevated in aorta elastin of rat with chronic liver cirrhosis induced by carbon tetrachloride when compared with normal rats. the provision of glutamine to marathon runners has resulted in a decreased, self-reported incidence of illness. increasing evidence -in vitro; and in vivo suggests that neutrophils in humans may benefit from exogenous glutamine. the provision of glutamine in vivo should replete the marked decrease in the blood concentration observed after stress such as clinical trauma or prolonged, strenuous exercise. beneficial effects of glutamine supplementation include increased phagocytic activity and reactive oxygen intermediate production in vitro; decreased neutrophilia and il-8 production (a chemoattractant for neutrophils) in vivo and ex vivo. the aim of the present study was to establish whether glutamine supplementation in vitro and in vivo affects neutrophil function at rest and after exhaustive exercise. in addition, it was planned to establish the presence of glutaminase in human neutrophils, which has not yet been achieved, although glutaminase is present in rat neutrophils. methods: blood samples were taken from marathon runners receiving either glutamine or placebo, immediately after and one hour after a race. measurements included the plasma concentration of glutamine (enzymatic assay), il-8 production (elisa), and neutrophil activity. the latter was measured with two different techniques for measuring oxidative burst in whole blood, one of which was a novel chemiluminescence assay (knight scientific ltd, u.k.) with the fluorescent label, pholasin, and two different stimuli, f-met-leu-phe (fmlp) and phorbol-myristate-acetate (pma). in addition, isolated whole cells and subcellular neutrophil fractions were assayed for the presence of glutaminase. results: the plasma glutamine concentration was reduced overall by 26% 1 hr after the race (p ͻ 0.02). there was an apparent decrease (only close to significance, p ͻ 0.13) in il-8 production in the glutamine group compared with the placebo group. neutrophil function did not change between groups at any stage. the incidence of illness was 46% higher in the placebo group than the glutamine group in the week after the race. neutrophils from four out of six subjects gave an increased response (39.2%) to fmlp when incubated with glutamine compared with no glutamine, and four out of four gave an increased response to pma (31.1%). in the fmlp experiments there were two individuals who did not respond to the addition of glutamine. however, the response was not diminished whether or not glutamine was present. in separate studies, the effect of glutamine on lipopolysaccharide-induced il-8 production was also monitored. conclusions: the provision of glutamine after prolonged, exhaustive exercise appears to modify exercise-induced neutrophilia via a reduction in il-8 production and to reduce the incidence of illness in the following week. in vitro data suggest a role for glutamine in neutrophil metabolism. disappointingly, little or no evidence of the presence of glutaminase was found in human neutrophils. the three different methods used, freeze-thaw, homogenisation, nebulisation were apparently not sufficient to break open the granules. current studies are addressing this problem. r. j. ward 1 and l. m. castell 2 departments of biochemistry, 1 university catholique de louvain, belgium 2 oxford university, oxford, u.k. it is essential that the developing muscle has adequate amino acids for the synthesis of actin and myosin as well as those required for a multitude of enzymes involved in muscle metabolism. with carbohydrates and lipids, the body is able to store a reserve as glycogen and triglycerides respectively; however this is not the case with amino acids creatine supplementation in increasingly being used as a dietary supplement by athletes during high intensity, short term exercise to improve physical performance since it is converted in the muscle to phosphocreatine. transporters which permit creatine to cross the muscle membrane namely crt1 and crt2 (a na ϩ and clј dependent mechanism) have now been identified. creatine uptake is enhanced by the ingestion of carbohydrate at the same time as supplementary creatine. this may be due to increased circulating levels of insulin or insulin-like growth factor 1. more recently attention has been focussed upon the various transporters for amino acids across the muscle membrane. certain criteria are needed for the amino acids to enter the blood which include the presence of specific carriers for its transport across cells of the gastrointestinal tract, such as enterocytes, as well as minimal metabolism within these cells. a wide number of different transporters has been identified, which include neutral amino acids and cationic amino acids. despite the evidence which suggests that supplementation with some amino acids can influence metabolism, and therefore athletic performance, much more experimental work is still required in this area. m. weiss 1 , t. barthel 1 , r. schnittker 1 , k. e. geiss 3 , w. falke 3 , and l. r. juneja 2 1 university of paderborn, germany 2 taiyo kagaku co., yokkaichi, japan, 3 isme gmbh mörfelden, germany in animal studies l-theanine was shown to influence neurotransmitter systems. thus it may be helpful in managing stress regulation. so we observed the down regulation after physical stress in the brain (measured by eeg-mapping) and in peripheral hormonal systems (plasma levels of catecholamines, cortisole, prolactine, serotonine, measured by hplc). n ϭ 14 healthy students consumed drinks containing either 0, 50 or 200 mg l-theanine in randomized double-blind trials in the min 6-14 after a near maximal bicycle step test. measurements were done directly after exercise (m1) and 30 (m2), 45 (m3), 60 (m4), 120 (m5) min after the drink. l-theanine seemed to accelerate the normalization of eeg spectral power in high frequency waves (barthel in this congress). the physiological return of increased hormon levels to basal levels / the circadianic rhythm up to m2 (catecholamines) or m5 (cortisole, serotonine, prolactine) was not influenced by the drinks. but in the l-theanine trials correlations between eeg spectral power and some hormones were altered (slow wave power/some catecholamines except norepinephrine/delta disappeared and new correlations with prolactine appeared). thus we conclude that l-theanine acts at the switch from the brain to the peripheral stress regulation and thereby supports physiological relaxing after severe exercise. polyamines the development from callus to plantlets, both activities increased, reaching the maximum at this latter stage. also sadenosylmethionine decarboxylase activity displayed a similar trend. all the activities were present in supernatant and in particulate fraction. higher activity of enzymes assayed in the small embryos rather than in the embryo with higher shape, was consistent with following polyamine accumulation. department of biology, laboratory of cell biochemistry, university of rome "tor vergata", rome, italy intracellular transglutaminase (tg, ec 2.3.2.13), which catalyzes the formation of ε-(γ-glutamyl)lysine isopeptide cross-links between polypeptides, has been related to a variety of important biological processes and in the development of senile cataract. the majority of the dry weight of the eye lens is composed of protein called crystallins. in the mammalian lens, these proteins are divided into three major classes: α-, -and γcrystallins. native -crystallins are oligomers, which elute in two or more size classes during gel filtration, ranging from 200-50 kda. they contain 7 different types of subunits, named b1, b2, b3, a1, a2, a3, ba4, ranging from 31-32 kda. in the rabbit eye lens two -crystallin subunits ( b2 and b3), among the water soluble proteins, have been shown to act selectively as acyl donors substrates for lens tg. calpains are cytoplamic ca ϩϩ -dependent cystine proteinases. the cleavage of αand -crystallins, the main substrates of lens calpain ii, has been associated to the increase of lens turbidity, due to insolubilization of peptides. we observed that tg-induced post-translational modification of b2-and b3-crystallins with polyamines, enhances their cleavage by calpain ii. this finding suggests that the enhancement of calpain ii activity, after conjugation of polyamines into -crystallins, could represent an important regulatory mechanism which may contribute to the opacification process of the eye lens, conducting to cataract formation. transglutaminases represent a family of enzymes, widely diffused in nature, from bacteria to plants and higher animals. the present discussion will focus on 4 isoenzymes in mammals, which have been well characterized from the structural and functional point of view. they act on tissular proteins catalyzing crosslinkage through isopeptide bonds at peptidyl glutamine and lysine residues or incorporation of small molecular weight primary amines, usually polyamines, in an irreversible, calcium dependent reaction. in several instances the expression of transglutaminases is regulated at the transcriptional level. these enzymes help in maintaining structural integrity of tissues intervening in wound repair and in cellular homeostasis at the levels of cell activation, receptor signaling, cell proliferation, differentiation and death. these general roles involve bis(guanylhydrazones) are a class of compounds known to interfere with the metabolism of polyamines by virtue of their ability to inhibit s-adenosylmethionine decarboxylase (samdc), a key enzyme of polyamine biosynthesis. this property has made them useful tools to study the biological functions of these compounds. a curious feature of bis(guanylhydrazones) is their structural relationship with two molecules involved in polyamine biosynthesis, namely spermidine and s-adenosylmethionine. the methylglyoxal derivative of bis(guanylhydrazones), mgbg, has been actively studied both in animal and plant systems. in the present work the male pollen from actinidia deliciosa has been utilized to investigate the role of polyamines on the pollen tube growth. the effect of several bis(guanylhydrazones) was tested on pollen germination, length of pollen tube, levels of free and conjugated polyamines and samdc activity. all bis(guanylhydrazones) tested (glyoxal-bis-guanylhydrazone, gbg, methylglyoxal-mgbg, methylpropylglyoxal-mpgbg, ethylmethylglyoxal-emgbg) inhibit pollen germination and their effect is dose-dependent. a clear reduction of spermidine, both in free and conjugated form, was observed, as well as a pronounced decrease in samdc activity. these results suggest that the mechanism by which bis(guanylhydrazones) reduce the germination of kiwi pollen is related to their effect on spermidine biosynthesis. molecules structurally related to polyamines (1,8diaminooctane, 1,9-diaminononane, 1,10-diaminodecane) and other inhibitors of their metabolism (cyclohexylamine, cha) are also tested on kiwi pollen germination. n. bagni 2 , d. bertoldi 1,2 , e. candioli 1 , l. martinelli 1 , and a. tassoni 2 1 istituto agrario, san michele a/adige, and 2 dipartimento di biologia, università di bologna, italy in the frame of the study aiming to enlighten developmental programs during regeneration in grapes, polyamine content (free and conjugated to hydroxycinnamic acids) and biosynthetic enzyme activities were assayed during somatic embryogenesis. aliphatic polyamines are growth regulators affecting plant growth and development both in vivo and during in vitro cultures, being involved in several morphogenic processes related ti their action in cell division. the study was conducted on samples of callus, embryogenic callus, embryo at different stages and plantlets of vitis vinifera brachetto and chardonnay cultivars induced from anthers and ovaries. polyamine content (putrescine, spermidine and spermine) free plus conjugated to percloric acid soluble fraction, referred to unit, was higher in the cv. brachetto than in the cv. chardonnay, and reached the higher levels in the fullydeveloped embryo stage. besides, ornithine decarboxylase activity resulted higher than arginine decarboxylase and during multiple catalytic processes: the receptor signaling activity (demonstrated only for isoenzyme 2) is related to an intrinsic gtp-ase activity of type 2 transglutaminase; the processes leading to control of cell proliferation, differentiation and death are mainly related to the protein crosslinking activity, while the cell activation is tentatively considered dependent on the polyamidation of endogenous proteins at glutamine residues. the knowledge on this last aspect lies far back in comparison to the other roles of transglutaminases and requires further accurate investigation, which must further extend to the role of the enzyme in human pathology. the examination of polyamine metabolism at the present time suggests that vitamin b12 is implicated in polyamines metabolism. literature data speak that spermine and spermidine stimulate activity of cobalamin-dependant methionine synthase, the enzyme that catalyses the recycling of homocysteine to methionine; polyamines inhibit methionine adenosyltransferase. beside the wellknow significance of vitamin b12, in transmethylation reaction, the significance of 5,-deoxyadenozyl cobalamin, except the conversion of methylmalonyl-coa to succinyl coa, is not well elucidates. methionine as s-adenosylmethionine (sam) is essential amino acid for polyamine biosynthesis. sam has frequently usage in treatment of liver diseases. according the mentioned facts the aim of our experiments is to exanimate the significance of application of vitamin b12 alone and altogether with methionine to rats without and with experimentally induced cholestasis. our preliminary results speak about the disturbance of polyamine metabolism in hepatic tissue of rats with cholestasis. application of methionine alone increases the amount of polyamine in rat liver tissue, in-group without cholestasis and with bile duct obstruction. the animal treatment with cobalamin has higher amount of polyamines and lower activity of polyamine oxidase in liver tissues in both groups. the effects of vitamin b12 may be in direct relation with the formation of 5,-methylthio deoxyadenosine (mta), the by-product of spermidine and spermine biosynthesis. the explanation the exact roles of vitamin b12 in polyamine metabolism of liver tissue need the futher investigations. department of molecular genetics, the weizmann institute of science, rehovot, israel exposure of mouse myeloma cells that massively overproduces ornithine decarboxylase (odc) but not of parental cells to ornithine results in a massive increase in the intracellular concentration of putrescine, followed by rapid cell death. the treated odc overproducing cells display fragmented nuclei, chromatin condensation and an oligonucleosome-size dna "ladder"; consequently, their death can be described as apoptosis. the apoptotic process induced by the accumulated putrescine involves the release of cytochrome c from the mito-chondria, activation of caspases cascades demonstrated by the cleavage of caspase-2 and parp, a substrate of caspase-3. the general inhibitor of caspases, bd-fmk, effectively inhibited parp cleavage but failed to inhibit cell death. the intracellular ca 2ϩ chelator bapta/am and the antioxidant bha inhibit parp cleavage. however, only bapta/am inhibit the induction of cell death. it seems that bha subverted the death into caspase independent pathway. treatment with bapta/am did not interfere with the accumulation of putresine following ornithine treatment, suggesting that the accumulated putrescine induces the elevation in the concentration of intracellular ca 2ϩ which then activates the apoptotic process. the dominant anti-apoptotic effect of bapta/am over egta suggests that internal stores are the main source of the elevated ca 2ϩ , but that putrescine is also capable of inducing influx of extracellular ca 2ϩ . extensive small intestine resection results in the loss of absorptive surfaces, acceleration of intestinal transit and, as a consequence, in malnutrition, weight loss, diarrhoea and other complications of short bowel syndrome. the availability of human recombinant growth hormone rgh and its stimulatory effects on gut growth suggested its use in the treatment of short bowel syndrome. the trophic response of gi tract epithelium to hormones such as growth hormone is mediated by polyamines, which are vital in cell proliferation. this study was undertaken in rats to: 1/ evaluate the effects of rgh by monitoring polyamine and amine metabolism parameters in the adapting short bowel and 2/ determine whether erythrocyte (rbc) polyamine concentrations reliably reflect the proliferative activity of the remaining bowel. seventy per cent resection of the small intestine of wistar rats was performed under ether anesthesia leaving equidistant lengths of bowel from pylorus and ileocecal valve. recombinant human gh (0.2 iu, s.c., saizen, serono, switzerland) was administered once daily for 5 or 10 days, to randomly selected rats on the second postoperative day. animals were sacrificed 8, 13 and 21 days after the operation. enzyme activities were measured with radioassays or fluorimetry. polymines were determined as dansyl derivatives by hplc/fluorimetry. gh treated animals had significantly higher intestinal odc and sat and lowel dao activities; higher (non-significant) mucosal growth index and polyamine concentrations than in untreated counterparts on 8 th postoperative day. thereafter the two groups did not differ in the investigated parameters. rbc polyamine concentrations were higher in operated verses control rats; rgh treatment had no significant effect. however, rgh treatment significantly reduced hepatic mao a and b activities. our results suggest gh accelerated the adaptive growth of the bowel remnant. they justify use of erythrocyte polyamine concentration measurement as the marker of small bowel proliferative activity. however, side-effects of this treatment must be considered. tissue transglutaminase (ttg) activity has been evaluated in different neural tissues, such as brain, spinal cord and peripheral ganglia, and appears to be expressed in cerebellar granule cells (cgn) as well as in astrocytes. the role of ttg in neuronal functioning is likely to be quite complex. other than the role during development, significant changes of enzyme activity have been evaluated in different neurodegenerative conditions. it is well known that nmda receptor activation may be able to trigger excitotoxicity. the nmda-induced injury is mainly associated to ion influx and subsequent calcium overload. the effects of nmda application to both, cerebellar granule cells and glial cell cultures, have been assessed. in cgn, ttg activity increased rapidly after a brief stimulation with 100 µm nmda, whereas in glial cell cultures, high levels of enzyme activity was obtained after incubation of 24 h in presence of the same concentration of nmda. such results rule out the possibility that excitotoxicity can modify numerous proteins making them better substrates of ttg, and this could contribute to enhanced ttg-modifications of proteins in response to excitotoxicity. the pote protein can catalyze both uptake and excretion of putrescine. the km values of putrescine for uptake and excretion (putrescine-ornithine antiport) are 1.8 µm and 73 µm, respectively. amino acid residues, cys62, trp201, glu207, trp292 and tyr425 are strongly involved in both activities, and that glu77, tyr92, cys210, cys285, cys286 and glu433 are moderately involved in the activities. mutations of tyr78, trp90 and trp422 mainly affected uptake activity, indicating that these amino acids are involved in the high affinity uptake of putrescine by pote. mutations of lys301 and tyr308 mainly affected excretion activity, indicating that these amino acids are involved in the recognition of ornithine. the putrescine and ornithine recognition site on pote was found to be located at the cytoplasmic surface and the vestibule of the pore consisting of twelve transmembrane segments. the cadb protein has 30% sequence homology with pote protein. cadb can catalyze both uptake and excretion of cadaverine. the km values of cadaverine for uptake and excretion (cadaverine-lysine antiport) are 20 µm and 300 µm, respectively. it was found that two glutamate residues (glu76 and glu204) and four tyrosine residues (tyr73, tyr89, tyr90 and tyr310) are involved in the both activities. the difference of the substrate recognition site on pote and cadb is discussed. a. lentini, b. provenzano, and s. beninati department of biology, laboratory of cell biochemistry, university of rome "tor vergata", rome, italy tissue transglutaminase (ttg, e.c. 2.3.2.13) is a protein cross-linking enzyme which catalyzes an acyl transfer reaction where the carboxamide group of a peptide-bound glutamine is the acyl donor, and a lysine residue the acyl acceptor. polyamines may act as acyl acceptors, leading to the formation of mono-and bis-(γ-glutamyl)derivatives. we provided evidence that ttg activity is directly associated to differentiation markers, and inversely related to cell proliferation and invasion. we have shown the in vivo reduction of experimental melanoma metastasis by i.v. injection of a plasmid (psg5) carrying the ttg gene sequence to c57bl6/n mice. tumor cell metastatization requires specific interactions with subendothelial basement membrane (bm) and migration through the endothelial wall, allowing the colonization of the target tissue. therefore, the investigation on the possible mechanisms responsible for ttg effects is focused on the posttranslational modification of bm proteins. we detected that "matrigel", a tumor-derived complex of bm proteins, modified with polyamines after ttg catalysis, reduces both melanoma cell adhesion and invasion in an in vitro metastatic assay. similar results were obtained using polyamines conjugated to laminin, one of the major bm components, as unique substrate. our findings suggest that the increase of bm proteins conjugated to polyamines may be responsible for impairments of the invasive properties of melanoma cells. we demonstrated that interferon-α (ifnα) induces apoptosis in human epidermoid cancer cells. tissue transglutaminase (ttgase) is an enzyme involved in the regulation of apoptosis through the inactivation of some cell components. among these eukaryotic initiation factor-5a (eif5a) is peculiar because its activity is modulated by the formation of the amino acid hypusine. recently, we found that growth inhibition induced by ttgase is paralleled by reduced hypusine levels. here we report the effects of ifnα on the apoptosis, ttgase modulation and eif5a activity in human epidermoid lung h1355 cancer cells. we have found that 48 h exposure to 2,500 iu/ml ifnα induces 50% growth inhibition and 15% apoptosis in h1355 cells. moreover, ifnα induced a 4-fold increase of ttgase activity and expression that already occurred after 24 h of exposure to the cytokine. this effect was paralleled by a 1.6-fold enhance of ttgase mrnas. ifnα induced also a 30% increased eif5a expression while an about 50% decrease of hypusine levels was observed. increased ttgase activity was paralleled by a decrease of hypusine content and of eif5a activity. therefore, ifnαinduced apoptosis could occur through an increase of ttgase activity and the mechanism by which ttgase regulates biological functions can be the reduction of eif5a activity. adometdc deficient mice k. nishimura 1 , f. nakatsu 2,3 , k. kashiwagi 1 , h. ohno 3 , t. saito 2 , and k. igarashi 1 1 graduate school of pharmaceutical sciences, chiba university, chiba, 2 graduate school of medicine, chiba university, chiba, and 3 cancer research institute, kanazawa university, kanazawa, japan the amd1 gene encodes s-adenosylmethionine decarboxylase (adometdc) that is one of the key enzymes of polyamine biosynthesis. to examine the physiological role of polyamines, we performed the targeted disruption of the gene in mice to generate spermidine-and spermine-free mice. although the level of adometdc mrna decreased by 50% in amd1 ϩ/ϫ mice, adometdc activity reduced only by 30% and spermidine and spermine contents did not change significantly. they showed normal phenotype and life span. to obtain amd1 ϫ/ϫ mice, we intercrossed amd1 ϩ/ϫ mice and determined the genotype of the resulting offspring. however, we could not obtain any amd1 ϫ/ϫ mice from 20 heterozygous intercrosses over. amd1 ϫ/ϫ embryos died early in development, between e3.5 and e6.5 days post coitum. in culture of blastocysts at e3.5, the shapes of all cell lines were normal, but amd1 ϫ/ϫ cells appeared to arrest the cell proliferation at day 3 after the onset of cell culture. the arrest of amd1 ϫ/ϫ cell proliferation was rescued by addition of spermidine. these data indicated that the lethal phenotype of amd1 ϫ/ϫ mice was caused by growth retardation by polyamine depletion at early developmental stage. the formation of active species such as h 2 o 2 and aldehydes during the oxidative deamination of biogenic amines by amine oxidases (ao) suggests for these enzymes a key role in cellular processes. the ability of bovine serum amine oxidase (bsao) to oxidase free amino groups of lysozyme and ribonuclease a has been observed indicating a possible ao involvement in the post-translational protein modification. furthermore, bsao inhibition by h 2 o 2 formed during substrate oxidation under limited turnover conditions was demonstrated, which may be relevant to cellular physiopathology. we have also observed that some inhibitors of mitochondrial amine oxidases (mao) protected human melanoma cell line (m14) against apoptosis. the protection by catalase of mao-substrates induced membrane permeability transition was also obtained in isolated rat liver mitochondria, thus confirming a role of mao-derived h 2 o 2 in apoptosis. enrichment in ao activity by treatment with vegetal ao has been obtained in a erythroleukemia cell line (k562), substaining the possibility to modulate the intracellular ao activity. an antiarrhythmic and cardioprotective effect of bsao has been also observed on isolated rat heart in reperfusion; a protective effect during anaphylaptic crisis has been shown "in vivo", thus suggesting aos as a possible therapeutic agents. tetrakis(3-aminopropyl)ammonium, a unique polyamine produced by an extreme thermophile, stabilizes nucleic acids at high temperature t. oshima and y. terui department of molecular biology, tokyo university of pharmacy and life science, hachioji, tokyo, japan an extreme thermophile, thermus thermophilus, produces tetrakis(3-aminopropyl)ammonium; a novel polyamine containing a quaternary ammonium nitrogen. to clarify the roles of the unique polyamine in thermophily, the effects of tetrakis(3aminopropyl)ammonium on biochemical reactions related to nucleic acids have been investigated. the unique polyamine stabilized both double and single stranded dnas and rnas. tm of a double stranded dna was raised by 8°c by the addition of 0.25 mm of tetrakis(3-aminopropyl)ammonium. at around the boiling temperature of water, depurination of dna takes place. other long polyamines produced by the thermophile such as caldopentaamine also stabilized dnas and rnas. we found that tetrakis(3-aminopropyl)ammonium prevents depurination most effectively. tetrakis(3aminopropyl)ammonium activated the protein biosynthesis catalyzed by a cell-free extract of the thermophile at high temperature. the effects of this unique polyamine on dna and rna polymerases are also being investigated and the results will be presented. tissue transglutaminase (ttg) catalyses the cross-link formation between glutamine (q) residues and nh 2 -donor molecules present in the cells (polyamines, lysine-donor proteins). recently, it has been correlated to neurodegenerative disorders characterised by polyglutamine (q n ) expansion, like huntington's disease. studies carried out on cell extracts revealed that glyceraldehyde 3-phosphate dehydrogenase (gapdh) was found covalently linked to q n domains. however, to date no structural data are available to solve the issue of which residues of gapdh are substrates for ttg. by coupling classical protein chemistry procedures and mass spectrometric techniques we achieved this goal by using as ttg substrates the substance p, an 11-aa peptide bearing the simplest q n domain (q 2 ), and polyamines of different size and shape as q-and nh 2 -donor, respectively. in the present study we report that out of the 26 lysines present in gapdh only three are sites of ttgasedependent cross-link formation in vitro. moreover, to characterize the ttg catalysed cross-link between gapdh and polyq protein we used a synthetic q 17 -peptide as ttg substrate in the catalysed reaction with polyamines. we found that any q residue is a potential ttg substrate, no matter the specific position in the sequence or the steric hindrance of the specific amine under investigation. cjf inserm 95-09, institut contre les cancers de l'apareil digestif (ircad), strasbourg, france as soon as the key role of odc in polyamine metabolism was recognised, it became the major target for selective inhibi-tion. s. harik presented in 1973 the first potent odc inhibitor, α-hydrazino ornithine. although efforts continued until today, with the aim to improve odc inactivation, 2-(difluoromethyl)ornithine (dfmo) remained the most important compound among all polyamine-directed drugs. a known anti-leukaemic drug, methylglyoxal-bis(guanylhdrazone), was recognised early on by g. williams-ashman and his collaborators as an inhibitor of adometdc, the other highly regulated biosynthetic decarboxylase, and served as matrix for more recent developments. in the course of the years selective inhibitors for all enzymes involved in polyamine biosynthesis and degradation were synthesised. moreover, a series of polyamineuptake inhibitors were reported. however, only some of these numerous compounds reached a stage above evaluation as growth inhibitors of cancer cells. owing to the sophisticated homeostatic regulation of the polyamines in cells and organs by de novo synthesis, degradation, uptake and release, and due to the fact that exogenous polyamines (i.e. gut polyamines) can be utilised by the vertebrate organism, the efficacy of selective enzyme and uptake inhibitors remained modest in cancer therapy. the fact the dfmo became the most important drug for the therapy of west and central african sleeping sickness relies on differences of vertebrate and parasite biochemistry. a novel approach, initiated by carl porter, involved the design and synthesis of structural analogues of spermidine and spermine, which do not share the growth-promoting effects of the natural polyamines. a very large variety of homologues, mostly of spermine, with different alkyl-substituents on the primary amino groups, have been studied systematically with regard to their ability to alter enzyme and polyamine patterns, and to inhibit cell growth. in addition polymine-like chains with interposed heteroatoms (0, s, si etc.), and analogues with rigid aliphatic chains (due to inbuilt double and triple bonds, or of small rings) have been explored. the structural analogues either mimic regulatory functions of the natural polyamines, and thus lead to the depletion of endogenous pools of putrescine, spermidine and of spermine, or they prevent growth effects of the natural polyamines by displacing them from functionally important binding sites. the later type may be considered as polyamine antagonists. the actual drugs usually exhibit to some extent polyamine mimetic and antagonist properties. at present several polyamine analogues are in clinical trial. however, after more than 25 years of active research, a polyaminerelated anticancer drug is still not available. one may conclude from this fact that the polyamines are an inappropriate target for cancer treatment. however, it is more likely that polyamine metabolism is a difficult target, because the differences between normal and cancer cells are mainly of quantitative nature. moreover, numerous mechanisms have developed in the course of evolution, which enable the vertebrate organism to prevent lethal polyamine losses. nine novel chemically modified polyamine (pa) analogs were evaluated for their ability to inhibit the pa biosynthesis in rat hepatoma g-27 cell-free system as well as the growth of caov tumor cells. the final concentration of oxy-and aminoadenosine pa analogs or two uracils modified pa analogs were 0.1 mm in the reaction mixture. bis(uracilyl)-analogs and 8-(2-oxyethyl)ami-no-9--d-xylofuranosyladenine supressed pa and putrescine synthesis and in the same conditions were more effective than dl-α-difluoromethylornithine (dfmo) -strong specific inhibitor of ornithine decarboxylase (odc). the other adenosine modified compounds could act both as activators of odc and inhibitors both diamine and polyamine oxidase activities in regenerating liver test system. in contrast to those mentioned above two uracils modified agents as well as dfmo were able to inhibit odc and to increase the rate of oxidative deamination of pa in the same system. thus bis(uracilyl) pa analogs were the most active and may be useful for further investigation as substances having potential antitumor and antiproliferative properties. several studies concerning the periodontal status in adult and adolescent patients treated with fixed ni-ti archwires have been performed, but until now it is not yet available any information about the influence of patient age on gingival tissue responses to ni-ti alloy. recently, researches by us demonstrated that the prolonged use for over 12 months of ni-ti appliances may contribute to local pathological proliferative processes early detectable only through salivary polyamine concentration increase. although other data from our laboratory showed that salivary polyamine amounts are age and sex-independent, nothing is known about the influence of the age on salivary polyamine content m subjects wearing ni-ti appliances. eighty patients, under orthodontic treatment for 12 months, were divided into four groups: the pre-, the mid-, the late-and the post-pubertal. salivary polyamine concentrations were determined by hplc. only the late pubertal group revealed a significant increase in both the spermine and spermidine content, while the other groups showed no modification. the results suggest that gingival pathological responses to a long-term appliance's use may be related to the endocrine modifications that occur in the late-pubertal age. sexual hormones appear to be in synergy with ni-ti alloy in promoting proliferative activity of gingival cells. the effects of polyamines on the synthesis of various σ subunits of rna polymerase were studied to determine how polyamines influence the functional specificity of transcription using western blot analysis. synthesis of σ 28 was stimulated 4.0-fold and that of σ 38 was stimulated 2.3-fold by polyamines, whereas synthesis of other σ subunits was not influenced by polyamines. stimulation of σ 28 synthesis by polyamines occurred at the level of transcription. since our hypothesis is that polyamines regulate macromolecular synthesis mainly at the translational level, we searched for a target protein, related to the polyamine stimulation of σ 28 synthesis, whose translation is altered by polyamines. stimulation of σ 28 synthesis was due to an increase in the level of camp, which occurred through polyamine stimulation of the synthesis of adenylate cyclase at the level of translation. polyamines were found to increase the translation of adenylate cyclase mrna by facilitating the uug codon-dependent initiation. analysis of rna secondary structure suggests that exposure of the shine-dalgarno (sd) sequence of mrna is a prerequisite for polyamine stimulation of the uug codon-dependent initiation. antitumor quinones are approved for clinical use and others antitumor quinones are in different stages of clinical and preclinical development. the efficiency of the quinonic compounds in inhibiting cancer cells growth is believed to stem from their participation in key cellular redox mechanisms with consequent generation of highly reactive oxygen species (ros). the ros is turn modify and degrade nucleic acids and proteins within the cells. recently, quinonic drugs were attached to the neurodecapeptide lh-rh and evaluated as potential drugs in the treatment of different tumours. we have synthesized several series of n-quinonyl amino acids in which five ω-amino acids are attached to p-quinones with different values of redox potentials. the attachment was made via michael-like reductive addition of the amino acids to the quinonic ring or via substitution of a chlorinated atom. the n-ω-quinonyl amino acids were characterized as to their ability to form semiquinone anion radicals by epr and cyclic voltammetry technique. the preparative methods, the redox potentials as well as the physical and spectral data ( 1 h-nmr, ir, uv-vis and hrms) of these n-ω-quinonyl amino acids will be presented. the de novo design of biologically active peptides and proteins, mostly has involved consideration and design of backbone conformations (secondary structures) such as α-helix, -sheets, -turns, etc. (η/ψ space). however, for many bioactive peptides and proteins, especially those critical for information transduction such as neurotransmitters, hormones, antigens, neurocrines, etc. molecular recognition via side chain moieties is of paramount importance. thus far, the specific three dimensional orientations of side chain groups ( angles; chi space) in terms of biological activity has received only modest attention. in part this may be due to the energetics of chi space compared to ramachandran space. in order to overcome the current limitations of evaluating the importance of chi space in critical biological functions related to disease and behavior, we have designed amino acids with novel structures and unique constraints in chi space ( 1 , 2 , etc.), with special attention to their ability to mimic the chi space of native proteins and peptides. we have developed novel and simple asymmetric synthetic methods for such amino acids, often with ees greater than 98%. incorporation of these novel amino acids into bioactive polypeptide neurotransmitters has provided ligands with unique biological activities that effect unique behaviors including feeding, sexual, pain, and addictive behaviors. (supported by grants from the usphs and nida.) protein technology, wallenberg laboratory ii, lund university, lund, sweden we describe a method for comparative quantitation and de novo peptide sequencing of proteins separated either by standard chromatographic methods or by one and two-dimensional polyacrylamide gel electrophoresis. the approach is based on the use of an isotopically labelled reagent to quantitate (by mass spectrometry) the ratio of peptides from digests of a protein being expressed under different conditions. the method allows quantitation of the changes occurring in spots or bands that contain more than one protein, and has a greater dynamic range than most staining methods. since the reagent carries a fixed positive charge under acidic conditions and labels only the n-terminal of peptides, the interpretation of tandem mass spectra to obtain sequence information is greatly simplified. the sequences can easily be extracted for homology searches instead of using indirect mass spectral based searches and are independent of post-translational modifications. dehydroamino acids and their derivatives play important roles as constituents of various natural products and as synthetic intermediates for the preparation of optically pure amino acids. a large number of amino acid derivatives containing a pyrazol-4-yl, isoxazol-4-yl and other heterocyclic moieties has been prepared as potential agonists or antagonists for central glutamate receptors in connection with (r,s)-2-amino-3-(3hydroxy-5-methylisoxazol-4-yl)propanoic acid (ampa), a bioisostere of (s)-glutamic acid. -hetaryl-α, -didehydroalanines might be considered as conformationally constrained ampa analogs and might be potential candidates for the synthesis of novel types of ampa analogs, for example, via their hydrogenation. compounds containing 2h-pyran-2-one ring are also very useful synthons in selective synthesis. recently we have shown their use for the preparation of (e)-α, -didehydroα-amino acid derivatives containing a pyrazolyl moiety (vraničar l, polanc s, kočevar m (1999) tetrahedron 55: 271). as a continuation of our investigation in this field we report here a detailed study of the transformation of 2h-pyran-2-one derivatives 1 with hydroxylamine (2, x ϭ o) and various hydrazines (2, x ϭ nr 2 ) towards novel types of (e)-and (z)α, -didehydroamino acid derivatives 3. in most cases, the reactions were performed under basic conditions in a mixture of ethanol and pyridine. depending on the substrate and the reagent used the reaction could be controlled to give either (e)-or (z)-isomers; in some cases decarboxylation to the corresponding enamines 4 also occured during the reaction course. some attempts to hydrogenate compounds 3 towards α-amino acid derivaties 5 by homogeneous or heterogeneous catalysis were also performed. analogs of endomorphin 1 and 2 were prepared to investigate the effect of the positional and c-terminal amide replacements and modifications on the biological activity. modifications in position 2 and 4 were studied. in position 2 several hydroxy-and serine related amino acids were incorporated, whereas in position 4 the amide bond was replaced by hydroxymethyl and allyl group. protected peptide derivatives were synthesized on 2chlorotrityl resin and further transformed to the corresponding derivatives in solution phase. among the analogs tested, in in vitro tests the most effective compound found was d-ser 2 -endomorphin ϫ2. quite surprisingly, the partial agonist/antagonist properties of the derivatives in receptor binding and g-protein stimulation tests have been shown behave differently. the differences in efficacy and receptor binding properties of the compounds may explain the discrepancies between the in vitro and receptor binding tests. we have been assessing the possible applications of substituted 2h-pyran-2-ones 1 containing α, -didehydroamino acid unit in their structure as dienes in [4ϩ2]-cycloaddition reactions. as dienophiles we have been using different acetylene derivatives as well as n-phenylmaleimide and maleic anhydride. as it is evident from the structure of 2h-pyran-2-ones upon the cycloaddition of acetylene derivatives the first intermediate formed (2) still contains the carbon dioxide bridge. in many cases 2 easily expels co 2 and substituted benzene derivative 3 is produced. when the alkenes are used, the first part of cycloaddition is the same as when acteylene derivatives are used, but after the extrusion of co 2 from the adduct 4 there are two possible paths: so formed cyclohexa-1,3-diene (5) is either aromatized into benzene derivative (3) or it acts as another diene with favourably positioned double bonds and unusual double cycloadducts (6) are formed. since co 2 -containing adducts are thermally unstable it is advantageous to use high pressure techniques. with the acetylene derivatives we have not been able to isolate co 2 -containing adducts (2), while with alkenes we have isolated, depending on the structure pattern of the compound 1, all three types of products: aromatized 3, co 2containing 4 and double adducts 6. especially the type 4 is suitable for further transformations into other heterocycles containing amino acid moiety. research group of peptide chemistry, hungarian academy of sciences, budapest, hungary among the opioid receptors family, the cloning of µ, k and δ receptors was followed by another member, named lc 132 or orl 1 . searching for an endogenous ligand for this receptor resulted in successful identification of a peptide (fggft garksarklanq) called noc or ofq. in vitro and in vivo studies have demonstrated that noc mediates a variety of biological actions. results from structure-activity experiments suggest that the whole sequence of noc is not required for binding to the lc 132 receptor and for full biological activities. noc(1-13)-oh seem to be the minimum and essential sequence for good interaction with the receptor. this neuropeptide, similarly other peptides, are unresisting for enzymatic degradation and the releasing metabolites are very weakly active or inactive. some previous experiments refer to that the c-terminal amidation may protect the peptide from degradation. we purposed to synthesize carbamoyl analogues of noc(1-13)-nh 2 , hoping that these derivatives retain the ability to bind lc 132 receptor and are resistant against biological degradation: phe-nh-co--ala-noc(4-13)-nh 2 phe--ala-nh-co-phe-noc(5-13)-nh 2 phe-gly-nh-co--hphe-noc(5-13)-nh 2 the first step in the synthesis of the carbamoyl analogues was the preparation of the building block [r-co-nh-co-nh-hc(rј)-cooh] by the classical method and then it was incorporated into the peptide by solid phase peptide synthesis. [ nonproteinogenic amino acids and their derivatives are valuable compounds from their pharmacological and biochemical effects. they can be used also in synthesis of peptides, as biomarkers, as the ligands in catalitically active transition metal complexes and so on. it is possible to prepare such amino acids by asymmetric hydrogenation of their prochiral precursors. however high enantioselektivities was reached only in the case of chiral phosphine-rhodium catalysts. recently we showed that high diastereoselectivity in the hydrogenation of linear dehydrodipeptides may be achieved over achiral catalyst in the catalytic system substrate -salts of ca ore mg -pd/c due to formation of dehydrodipeptides complexes with ions ñà 2ϩ or mg 2ϩ and hence increasing of the conformational rigidity of substrates. this phenomenon may as well happen in other dehydrodipeptides, containing nonproteinogenic amino acids. among unnatural amino acids those bearing heterocyclic rings have attracted considerable attention due to the possibility of the heteroatoms participation in coordination with ions of metals. we have received some n-acyldehydrodipeptides, containing in the prochiral unit of dipeptides nonproteinogenic dehydroamino acids. all this n-acyldehydrodipeptides form in alcohol solution complexes with cax 2 and mgx 2 where one metal ion binds together several (up to 5) substrate molecules. this kind of complexation leads to the increase of conformational rigidity and to the diastereoface shielding of cϭc bond. moreover the combination of cations (ca 2ϩ or mg 2ϩ ) and anions (x) and the sequence of their mixing with a substrate determine the assembly inside complex particles and hence the sign and degree of asymmetric induction. indeed hydrogenation of these complexes formed in situ over achiral heterogeneous catalyst (pd/c) gives two diastereomers of corresponding n-acyldipeptides with the substantial increase of the reaction diastereoselectivity (up to 80%). in living cells, glutamine represents one of the main storage forms of nitrogen and is a major physiological source of ammonia for the biosynthesis of aminoacids, aminosugars, purine and pyrimidine nucleotides and coenzymes. glutamine-dependent amidotransferases perform nitrogen transfer from the amide group of glutamine to various electrophiles. when the latter is fructose-6p, the product of the reaction catalysed by glucosamine-6p synthase is d-glucosamine 6-phosphate, a structural building block of peptidoglycane (bacteria) and of chitin and mannoproteins (fungi). fluorinated analogues of glutamine are expected to interfere with this biological process due to the strong electron withdrawing effect of fluorine atom (without significant steric consequence), inducing modulation of binding and/or electronic properties. these compounds might therefore behave as reversible or irreversible active site-directed enzyme inhibitors. synthesis of optically active 1 from d-serine will be described and first results in the biological evaluation on glucosamine 6-phosphate synthase will be included. o. melnyk 1 , d. bonnet 1 , e. loing 2 , l. bourel 1 , and h. gras-masse 1 1-umr 8525, 2-sedac-therapeutics, biological institute of lille, france lipopeptides, owing to their ability to cross passively the cell membrane or biological barriers, are unique tools for the intracellular delivery of bioactive peptides. the structure of the lipophilic moiety is known to have a profound effect upon the interaction with the membrane and its alteration. the stepwise solid phase synthesis of lipopeptides is limited by the necessity to perform a complex rp-hplc purification following the cleavage and deprotection step. in addition, the harsh conditions used during the final acidolysis procedure does not allow the introduction of unsaturated or sensitive fatty acids. to speed up the access to large lipopeptides modified by various fatty acid moieties or cholesterol derivatives, we have designed novel synthetic methods which involve the chemoselective reaction of fully deprotected and purified hydrazinopeptides with fatty acid succinimidyl esters or glyoxylyl derivatives. application of these methodologies to the c-terminal 95-135 portion of interferon (ifn)-γ allowed the selection of the optimal lipopeptide ifn-γ agonist, as determined by its ability to induce the expression of surface mhc-ii molecules through interaction with the intracellular components of ifn-γ receptor. graduate school of science, osaka city university, osaka, japan glutamate receptors in mammalian cns are implicated in the construction of memory and early learning as well as in the pathogenesis of neuron damage to cause various neuronal diseases. in recent years, we have studied the conformational role of l-glutamate when it binds to the receptors through the synthesis of l-2-(carboxycyclopropyl)glycines (ccgs) and their related analogs. the works have demonstrated that not only the receptors require a specific conformation of l-glutamate, but also these analogs can be used as important tools for the neuropharmacological research. among them, dcg-iv, a 3јsubstituted analog of ccg-i, is used as a potent and selective agonist of mglur2. as an extension of these works, next program was focused on the synthesis of α-substituted glutamate analogs which would enable to develop potent and subtype-selective ligands for mglurs and transporters. α-alkoxymethylglutamate and ly354740 and its c5 epimer were chosen for the synthetic targets, since the former slightly restricts the glutamate conformation to an extended form and the latter rigidly fix to an extended or a folded form on its bicyclo[3,1,0]hexane skeleton. the key to the synthesis was a stereoselective construction of the quarternary carbon center, which was efficiently performed based on an asymmetric version of the strecker synthesis. details of the synthesis and their neuropharmacological activities will be described. using a genetically modified organism a broad variety of linear unsaturated amino acids are now accessible in enantiomerically pure form via this methodology, which can be used as starting materials for the synthesis of highly functionalized pipecolic acid derivatives. these compounds can be used to restrict conformations in polypeptides or can serve as scaffolds in synthesizing libraries for drug discovery. the synthetic approach involved both a pd-catalyzed amidopalladation reaction of alkoxy-allenes, in which the nh is added across one allene double bond and a ruthenium catalyzed ring closing metathesis step, to form a benzyloxypipecolic acid. further reaction of this n-sulfonyl-iminium-ion precursor with a nucleophile results in the formation of cis-substituted pipecolic acids. due to the unique electronic properties of fluorine, incorporation of α-fluoroalkylated amino acids is a new approach to design biologically active peptides with increased metabolic stability and defined secondary structure and provides a powerful nmr label for spectroscopic investigations. the application of proteases especially for cn-ligations is an attractive alternative to chemical methods, because the enzymatic formation of peptide bonds is highly regio-and stereospecific and, therefore, does not require large efforts to protect side chains of trifunctional amino acids. recently, the enzyme-catalyzed incorporation of α-fluoromethyl amino acids into the p 2 , p 3 and p 2 ј-position (nomenclature according to schechter and berger) of peptide fragments has been successfully performed. carboxypeptidase y was now shown to be suitable to catalyze the incorporation of α-trifluoromethyl alanine into the p 1 position of peptides. furthermore, the general applicability of the substrate mimetic concept in enzymatic peptide synthesis was expanded to the transfer of c-terminal α-fluoroalkyl substituted amino acids. generally, each trifluoromethyl-and difluoromethyl amino acid 4guanidinophenyl esters can be applied as acyl donor in trypsin and chymotrypsin catalyzed peptide bond formation independently of the acyl moiety and the natural enzyme specificity, respectively. via these two approaches, incorporation of αfluoroalkylated amino acids into the p 1 position of peptides using enzymatic methods was successfully applied for the first time. this investigation was performed in search of new 2јdeoxynucleoside analogues modified at 3ј-and 5ј-positions with amino acids and possessing antiviral activity. substrate mimetics strategy: an efficient approach to protease-catalyzed peptide ligation n. wehofsky 1 and f. bordusa 1,2 1 max-planck-society, research unit "enzymology of protein folding", halle, and 2 institute of biochemistry, university of leipzig, germany two main drawbacks seriously restrict the synthetic value of proteases as reagents in peptide fragment coupling: (1) native proteolytic activity and, thus, risk of undesired peptide cleavage; (ii) limited enzyme specificities restricting the amino acid residues between which a peptide bond can be formed. the latter can be overcome by the use of substrate mimetics. contrary to common acyl donors, substrate mimetics bear a binding site specific ester leaving group instead of having a specific amino acid moiety at the c-terminus of the acyl residue. this replacement mediates the acylation of the protease by nonspecific acyl residues. deacylation of the artificial acyl enzyme intermediate by the amino component added results in peptide bond formation regardless of the primary specificity of proteases enabling nonspecific coded and noncoded amino acid derivatives and even non-amino acid-derived acyl moieties to be coupled. the successful application of these artificial substrates for model peptide ligations catalyzed by the argspecific trypsin, the glu-specific staphylococcus aureus strain v8 protease (v8 protease), and α-chymotrypsin, which is specific for aromatic amino acid moieties, will be demonstrated. new development in the tritium labelling of peptides and proteins using solid state catalytic isotopic exchange with spillover-tritium yu. a. zolotarev 1 , a. k. dadayan 1 , b. v. vaskovsky 2 , and n. f. myasoedov 1 1 institute of molecular genetics, russian academy of sciences, and 2 shemyakin-ovchinnikov institute of bioorganic chemistry, russian academy of sciences, moscow, russia the reaction of high temperature solid state catalytic isotope exchange (hscie) of hydrogen in peptides and proteins with spillover-tritium was studied. the reaction ability of amino fragments in hscie was shown to depend both of their structure and on the availability and the mobility of the polypeptide chain. [ 3 h] peptide analysis using 3 h nmr spectroscopy was carried out, and the modified fragment [ 3 h]actc 4-10 (met-glu-his-phe-gly-pro), with molar activity of 80 ci/mmol and [ 3 h] zervamicin iib (ac-trp-ile-gln-iva-ile-trh-aib-leu-aib-leu-hyp-gln-aib-hip-aib-pro-phl, where aib ϭ 2amino-isobutyric acid) with molar activity of 70 ci/mmol was produced. the obtained preparations completely retained their biological activity. with the -galactosidase protein from termoanaerobacter ethanolicus as example, the interrelation between the protein's tertiary structure and the isotopic label distribution incorporated due to the hscie reaction was used. the labeled protein with the molecular mass of 83 kda was brought to fragmentation by glu-proteinase. peptide fragments were separated by hplc and were identified by maldi mass spectrometry. a correlation between the position of the amino acid fragment in the protein tertiary structure and its reaction ability in the hscie reaction was obtained. data on the retention of thegalactosidase enzymatic activity in condition of tritium label introduction are supplied. taurine chloramine modulates cytokine production by peripheral blood mononuclear cells m. chorą z . y 1 , e. kontny 1 , j. marcinkiewicz 2 , and w. maśliń ski 1 1 institute of rheumatology, warsaw, and 2 jagiellonian university, cracow, poland objective. proinflammatory cytokines are produced in a cascade fashion, where monocyte-derived tnfα and il-1 trigger production of il-6 and il-8 also in the other cell types. we reported recently that taurine chloramine (tau-cl) inhibits production of the latter cytokines in fibroblast-like synoviocytes. in present study the effect of taurine (tau) and tau-cl on tnfα, il-1 and il-6 production was examined. methods. peripheral blood mononuclear cells from healthy volunteers were stimulated with lps (24 h) in the presence of tau or tau-cl (100-500 µm). cytokine production was measured in culture supernatants (secreted) and cell lysates (intracellular) using elisa. results. in lps-stimulated cells both secreted and intracellular il-1 and il-6 were inhibited by tau-cl with ic 50 ϸ 300 µm and 425 µm, respectively. however, tau-cl exerted dual effect on tnfα production, raising it slightly (1.5 times) at low (100-200 µm) while reducing it (ic 50 ϸ 450 µm) at higher concentration. tau did not significantly affect cytokine production. tau-cl modulates proinflammatory cytokine cascade and eventually might down-regulate it when present at high (ͼ300 µm) concentration. department of biology, division of general physiology, university of oslo, blindern, norway every living cell must deal with osmotic and hydrostatic pressure changes between its environment and its interior and counteract volume changes. swelling activated channels is one group of effectors in the cell membrane that is important in preventing excessive volume increases by releasing inorganic ions and organic solutes that include taurine. such channels are associated with several physiological processes, but little is known about their activation mechanisms. we have used a rat thyroid cell line (frtl-5) to investigate the activation of a swelling sensitive [3h]taurine efflux pathway. hypo-osmolality and thyrotropin (tsh, 500 µm) increased transiently the rate coefficient for [3h]taurine efflux with a similar pattern of activation. the phosphodiesterase inhibitor 3-isobutyl-1-methyl xanthine (100 µm) increased the swelling activated efflux rate coefficient 6.4 times above the control level and the camp analogue dibutyryl-camp (500 µm) activated the pathway. these results indicate that both swelling and tsh activation of the taurine efflux pathway are mediated by camp. other aspects of the signal transduction pathway will be discussed. based on the inclination of n-chloroamines to disproportionate, the endogenous bactericidal agent n-chlorotaurine (nct), mainly at ph ͻ 7, is accompanied by n, ndichlorotaurine (ndct). since pure ndct could be synthesized as crystalline sodium salt, a first evaluation of its chemical and bactericidal properties was possible. ndct-na (melting point: 162-4°c, decomp.) is very well soluble in water and poorly in ethanol where it can be recrystallized from. on storage the initial ph 5 of the aqueous solution decreases which correlates with a decrease of oxidation capacity of 1.8% per day, probably originated by the elimination reaction r-ch 2 -ncl 2 ae r-chϭncl ϩ h ϩ ϩ cl ϫ as a first step. contrary to nct-na an immediate decomposition occurs when ndct-na comes into contact with undiluted dmso. in aqueous solution, however, ndct does not react with dmso. the bactericidal activity of 55 mm ndct at ph 7 and 5 against the gram-positive bacteria s. epidermidiand two strains of s. aureus was the same as with equimolar nct though ndct bears twice the oxidation capacity. against the gramnegative bacteria e. coli, p. aeruginosa, and p. mirabilis, however, a significantly higher activity of ndct was observed at both ph. the mechanism of taurine chloramine inhibition of fibroblastlike synoviocytes growth e. kontny 1 , m. kurowska 1 , j. kowalczewski 1 , i. janicka 1 , j. marcinkiewicz 2 , and w. maśliń ski 1 1 institute of rheumatology, warsaw, and 2 jagiellonian university, cracow, poland objective. in rheumatoid arthritis (ra) enhanced proliferation of fibroblast-like synoviocytes (fls) leads to hyperplasia of synovial membrane (sm). therapeutic approaches to inhibit an excessive growth of these cells are not satisfactory. thus, we investigated the effect of taurine (tau) or taurine chloramine (tau-cl) on ra fls growth. methods. fls isolated from sm of ra patients were stimulated for 72 hours with rhpdgf or rhtnf-α. tau or tau-cl were added at 100-250 µm concentrations. cell proliferation was determined by incorporation of 3 h-thymidine into dna. expression of proteins regulating cell-cycle progression or apoptosis, was estimated by western blotting. results. at 250 µm concentration tau-cl inhibited (by ϸ 70%) both pdgf-and tnf-α-triggered cell proliferation and similarly reduced expression of pcna (a cofactor for dna polimerase δ). however, tau-cl affected neither the expression of cell-cycle inhibitors (p21, p27) nor anti-apoptotic bcl-2 protein. tau has no effect on tested responses. conclusion. we report that tau-cl inhibits proliferation of ra fls by affecting expression of pcna, that is critical for cell cycle progression. e. kontny 1 , k. szczepań ska 1 , j. kowalczewski 1 , m. kurowska 1 , i. janicka 1 , j. marcinkiewicz 2 , and w. maśliń ski 1 1 institute of rheumatology, warsaw, and 2 jagiellonian university, cracow, poland objective. proinflammatory cytokines play critical role in the pathogenesis of rheumatoid arthritis (ra). we reported recently that taurine chloramine (tau-cl), but not taurine (tau), inhibits production of il-6 and il-8 by fibroblast-like synoviocytes (fls). in present study the mechanism of tau-cl inhibitory action was investigated. methods. fls isolated from synovial membrane of ra patients were stimulated with rhil-1 . tau or tau-cl were added at 250-500 µm concentration. after 0.5-2 h or 4 h the dna binding activity of nfkb and ap-1 (emsa) and the expression of il-6 and il-8 mrnas (rt-pcr) was examined, respectively. results. il-1 raised nfkb and ap-1 activity, followed by the elevation of cytokine mrnas expression. tau-cl, but not tau, reduced both the expression of cytokine mrnas (il-6 ͼ il-8) and the activity of transcription factors (nfkb ͼ ap-1). conclusion. tau-cl inhibits transcription of il-6 and il-8 genes due to its ability to diminish the activity of key transcriptional factors, that regulate these proinflammatory cytokine expression. institut für organische chemie, universität bremen, germany the synthesis of taurine and hypotaurine from cysteine can be followed up in astroglia-rich primary cultures obtained from brain of neonatal wistar rats. using 1 h and 13 c nuclear magnetic resonance spectroscopy cell extracts of glia cells incubated with 13 c labelled cystein show the label subsequently in hypotaurine, taurine, lactate and gluthathione. within 72 h, 35% of the total intracellular hypotaurine and 22.5% of taurine were newly synthesized from cysteine. both metabolites were also released to the medium. neurones are capable to take up both metabolites from glia media to recruit their organic osmolite. part of newly synthesized glutathione and lactate are also exported to the medium. by this means lactate may serve as an energy substrate for neurons. in-vivo mrs of lactate is obscured by line splitting and signal overlay. using various two dimensional pulse sequences as spin preparation sequences prior to localized single voxel, in-vivo mrs or spectroscopic imaging sequences will provide homonuclear non-coupled resonance signal of taurine. these singlet signals are detectable and quantified. diffusion weighted spectroscopy is used to characterize the mobility of taurine in living tissue. department of pharmacology and ophthalmology and visual sciences, texas tech university health sciences center, lubbock, texas, u.s.a. taurine depletion, whether by removing taurine from the diet or by using a taurine transport inhibitor, has demonstrated various pathologies in various animal models including man. the first reported pathology associated with dietary taurine depletion was in the retina of the cat. in this animal model, taurine deficiency resulted in disorganization of the tapetum (the light reflecting membrane), disruption of the outer segments, photoreceptor dysfunction, and cell loss. when allowed to proceed for a number of months the result was blindness. subsequent studies demonstrated that taurine deficiency also had a profound effect on cardiac physiology. echocardiograms of the left ventricle of the cat heart depleted in taurine showed a dilated cardiomyopathy reflected in an extended end-diastolic diameter and an extended end-systolic diameter. dietary taurine supplementation resulted in the above parameters returning to normal. the cat is a difficult animal model to use for a variety of reasons and thus the rat was chosen to further probe the consequences of taurine depletion. unfortunately, the tissue taurine levels in the rat do not respond to dietary taurine depletion, and thus other experimental means had to be designed. guanidinoethanesulfonic acid (ges), an analogue of taurine and a taurine transport inhibitor, has been utilized for the last 20 years to deplete rat tissues of their taurine content (j. e. shaffer and j. j. kocsis, methods of reducing tissue taurine levels, and r. j. huxtable, h. e. laird, and s. lippincott, rapid depletion of tissue taurine content by guanidinoethyl sulfonate. in: the effects of taurine on excitable tissues, spectrum publications, new york, 1981) . ges, when administered to rats in their diet in the drinking water as a 1-1.5% solution, usually produces a significant decrease in the taurine content of all tissues within one week of treatment. within 3-5 weeks the levels of taurine reach their nadir (20-50% of control) and continued feeding of ges does not further reduce the levels of taurine. unfortunately, ges replaces taurine and thus one must always consider the effects of ges on physiological events that occur within the tissues in question. again, as in the cat, taurine depletion manifested itself in retinal pathology: disruption of the photoreceptor structure, dissociation of the disc membranes, and abnormal electroretinograms (erg). other animals models such as the monkey have also demonstrated structural disorganization of the photoreceptors and abnormal ergs. finally, the ultimate test is whether taurine deficiency has an effect in man. in 1985, koppel and associates (geggel et al., n. eng. j. med. 312: 142-146, 1985) demonstrated that children on long term parenteral nutrition devoid of taurine had abnormal erg. supplementation of the parenteral nutrition with taurine restored the ergs to normal in the majority of the children. because of these definitive studies, all infant formulae in the united states, europe and japan now contain taurine. (supported in part by a grant from the taisho pharmaceutical co., ltd., tokyo, japan.) department of pharmacology and ophthalmology and visual sciences, texas tech university health sciences center, lubbock, texas, u.s.a. it has been demonstrated previously in our laboratory that taurine inhibits the phosphorylation of an ϳ44 kdalton protein present in the mitochondrial fraction of the rat heart (j. mol. cell. cardiol. 26: 1675 -1689 , 1994 . upon administering 1.5% guanidinoethanesulfonic acid (ges) in the drinking water of rats for 6 weeks, the taurine levels in cardiac tissue decline by 75%. however, the phosphorylation of a ϳ44 kdalton protein in the mitochondrial fraction of the heart tissue increased by 85% (j. mol. cell. cardiol. 26: 1675-1689, 1994) . reversal of these effects could be accomplished by feeding the rat 1.5% taurine in the drinking water for 6 weeks. the ϳ44 kdalton protein was isolated by 1-dimensional polyacrylamide gel electrophoresis (page) using traditional glycine buffers followed by re-electrophoresing the cut out portion of the gel, which corresponds to the ϳ44 kdalton protein, on a tricine-buffered gel resulting in sufficient pure protein for digestion and sequence analysis. it was determined that the ϳ44 kdalton was pyruvate dehydrogenase (amino acids 12: 139-144, 1997) which indicates a significant regulatory role for taurine in energy metabolism in cardiac tissue. these data are of significant interest in that taurine may be an additional effector of this enzyme or of the enzyme complex. studies are in progress to determine if taurine has a direct effect on either the kinase (inhibition) or the phosphatase (stimulation) associated with the pyruvate dehydrogenase complex. it has also been demonstrated and now reported that taurine depletion utilizing ges in vivo in rats affects the phosphorylation of myelin basic protein (mbp). in these experiments the animals were given ges (1%) for 6 weeks in their water and then killed; the hearts were removed and homogenized. the homogenate was then incubated with buffer containing mbp (50 ì) and radioactive atp for 6 minutes. animals were also treated with taurine (1%) in their drinking water for 4-5 weeks or treated with taurine following the ges treatment. page of the incubation mixture, autoradiography on the dried gel, and densitometry of the mbp band gave the following results: relative % activity ϯ sem (normalized to mg protein) control 100 ϯ 20 (n ϭ 6) ges-treated 147 ϯ 28 (n ϭ 6) p ͻ 0.05 (paired 5-test) control 100 ϯ 16 (n ϭ 5) taurine-treated 95 ϯ 17 (n ϭ 5) p ͼ 0.05 control 100 ϯ 32 (n ϭ 4) ges followed by taurine 95 ϯ 37 (n ϭ 4) p ͼ 0.05 these data confirm previous reports that it is easier to deplete animals of their cardiac taurine content than it is to raise the levels of taurine. these data on the effects of taurine depletion (increase in mapkinase activity) and taurine supplementation (no change in mapkinase activity) on mapkinase activity reflect these past observations. (supported in part by a grant from the taisho pharmaceutical co., ltd., tokyo, japan.) act additively, or in the case of mpo negated each other's effects. regarding our results there is significance to pharmacological regimens which enhance the supply of propofol or taurine in whole blood. these regimens influence considerably pmn intracellular amino acid concentrations and it is this pmn "labile free amino acid pool" which may be one of the determinants in cell nutrition positively or adversely affecting pmn immune functions. taurine supplementation to pmn seems to interfere independently from the effects of propofol on pmn free amino acids and on immune functions tested. institut für hygiene, universität innsbruck, austria n-chlorotaurine (nct) is a long-lived oxidant produced by activated human leukocytes during the oxidative burst. it has activity against a broad spectrum of pathogens including bacteria, fungi, viruses and helminths. as a special feature, the killing of microbes by nct can be increased significantly in the presence of ammonium and also of some amino acids (alanine, glycine). this is explained by transfer of the active chlorine ("transhalogenation") from nct to ammonium and amino acids to form the corresponding, stronger microbicidal n-chloro derivatives monochloramine and n-chloro amino acids, respectively. especially addition of ammonium to nct provokes rapid inactivation of fungi and even mycobacteria. because of its good tolerability, nct solution can be applied to human tissue to treat infections. in ammoniumcontaining body fluids like nasal mucus and urine, fungi and bacteria are killed within minutes. therefore, amino compounds of human secretions can be transformed to the above quoted endogenous and highly microbicidal chloramines by nct via transhalogenation -a unique property of an antimicrobial agent. successful treatment in cases of urinary tract and otorhinolaryngological infections and conjunctivitis in phase iia clinical trials provides strong support for this concept. the endogenous sulfonated amino acid taurine has numerous functions in the central nervous system, including positive modulation of gaba a receptor function. recently we found that mice lacking protein kinase c -epsilon (pkcε) are behaviorally and biochemically supersensitive to ethanol and other positive allosteric modulators of the gaba a receptor. in addition, these mice consume 50-75% less ethanol and wildtype controls in two separate self-administration paradigms. microdialysis studies in pkcε-deficient mice revealed elevated extracellular levels of taurine, which may account for the supersensitivity of gaba a receptors in these mice and resulting decreases in ethanol intake. in light of the fact that the taurine derivative acamprosate (calcium acetylhornotaurinate) is moderately effective in reducing craving and relapse in detoxified alcoholics, we examined the effect of taurine-related compounds on acute ethanol consumption in a two-bottle choice paradigm in rats. taurine (10-200 mg/kg ip) was only slightly effective in reducing ethanol intake but not preference, while the highest dose of taurine (200 mg/kg) also suppressed water intake. the taurine precursor hypotaurine (10-100 mg/kg ip) was also weakly effective in reducing ethanol intake but not preference or water intake. the most effective compound tested was homotaurine (10-100 mg/kg ip), which suppressed ethanol intake and preference by approximately 50% without altering water intake. these data indicate that endogenous taurine may regulate sensitivity to ethanol and subsequent ethanol self-administration, and that taurine-related compounds may be effective in reducing alcohol intake in humans. we are currently exploring whether taurine and related compounds are able to suppress ethanol-stimulated mesolimbic dopamine release, a primary neural substrate of ethanol reinforcement. (this work was supported by funds provided by the state of california for medical research on alcohol and substance abuse through the university of california at san francisco.) organic osmolytes, such as taurine, regulate a cell's osmotic balance without directly altering either the cell's ionic composition or the membrane potential. this property of the organic osmolyte often renders the cell resistant to damage during a pathological insult. indeed, ischemia is associated with a massive efflux of taurine from the cell, an event that minimizes the severity of the osmotic imbalance that develops from the accumulation of lactate, inorganic phosphate and sodium. however, taurine depletion also activates specific signaling pathways that provide further protection to the cell. among the signaling pathways activated by taurine depletion is a pi 3-kinase (phosphatidylinositol 3-kinase) linked pathway that catalyzes the phosphorylation and inactivation of the pro-apoptotic factor, bad. taurine depletion also activates protein kinase c, which in turn elevates the intracellular content of the antiapoptotic factor, bcl-2. increases in the extracellular osmolality by either addition of 20 mm taurine or 25 mm mannitol to the incubation medium activates similar pathways. however, pi 3kinase assumes a more important role in the mannitol treated cell than the taurine depleted cell. moreover, p38 map kinase is activated by mannitol treatment but not by taurine depletion. despite these differences, both taurine depletion and mannitol treatment protect the cell against hypoxia-induced apoptosis. the data suggest that osmotic stress protects the cell against apoptosis by increasing cellular levels of bcl-2 and promoting the inactivation of bad. this work was supported by a grant from the american heart association. a dummy or a protagonist on the stage of inflammation? r&d department, zambon group, bresso, milan, italy amino acids are usually present in large excess in healthy and the excess is used as source of calories. however, metabolic alterations are observed in ill patients and preferential retention of sulphur amino acids (saa) occurs during the inflammatory response. the metabolism of cysteine is modified during the acute phase of sepsis in rats. sulphate production is lower, whereas the higher liver production of taurine seems to play a protective role; glutathione concentration is greater in liver, kidney and other organs and cysteine incorporation into proteins was higher in spleen, lung and plasma (acute phase proteins) while albumin level decreases. another important phenomenon is the impairment of methionine conversion to cysteine during stressed condition. premature infants or hiv patients synthesise cysteine from methionine at a much lower rate. thus, the metabolic flow through the trans-sulphuration pathway may be insufficient to meet the glutathione and cysteine requirement in critical conditions. the pro-inflammatory cytokines, interleukin-1, interleukin-6 and tnf-α are the main initiates that alter protein and amino acid metabolism. in this complex picture, saa supply may contribute to the immune system regulation. department of applied biological chemistry, the university of tokyo, japan the intracellular level of taurine is maintained not only by the taurine transporter that transports extracellular taurine inside cells but also by endogenous synthesis from methionine and cysteine. we therefore investigated the regulation of both the taurine transporter and the cysteine dioxygenase, one of the main taurine biosynthetic enzymes, in hepg2 human liver cells. the intracellular taurine content of hepg2 cells was extremely increased by culturing in a hypertonic medium. the activity of taurine transport was increased by hypertonic conditions, which was due to the increased expression of the taurine transporter gene. the expression level of the cysteine dioxygenase gene was also increased, suggesting that the expression levels of both the taurine transporter gene and the cysteine dioxygenase gene were regulated in harmony by hypertonic conditions to accumulate taurine inside cells. on the other hand, the activity of taurine transport in hepg2 cells was down-regulated on culturing the cells in taurine-rich medium, the expression level of the taurine transporter gene being also markedly decreased. however, the expression level of the cysteine dioxygenase gene was not significantly altered under taurine-rich conditions, indicating that the gene expression of the taurine transporter and that of the cysteine dioxygenase was independently regulated by extracellular concentration of taurine. the amino acid, taurine, is found in very high concentration in the heart. although its most important putative function is osmoregulation, it also serves as a regulator of cell growth. isolated cardiomyocytes exposed to medium containing 1 nm angiotensin ii undergo hypertrophy, a process blocked by 20 mm taurine. the amino acid also inhibits angiotensin iiinduced activation of c-fos, upregulation of atrial natriuretic factor and induction of tgf-betal. central to virtually all of these actions of angiotensin ii is the translocation and activation of key protein kinase c (pkc) isoforms. therefore, we proposed that taurine inhibited the hypertrophic actions of angiotensin ii by interfering with the translocation of one or more of the pkc isoforms. indeed, taurine and angiotensin ii exhibited different effects on the translocation of several pkc isoforms. while taurine promoted the translocation of pkcalpha, pkcdelta and pkcepsilon from the particulate fraction to the cytosol, the levels of the three isoforms in the particulate fraction were elevated following treatment with angiotensin ii. by contrast, both taurine and angiotensin ii increased the pkczeta content of the particulate fraction and the pkcbeta2 content of the cytosol. when the isolated cardiomyocytes were incubated with medium containing both angiotensin ii and taurine, the effects on pkc distribution were largely additive. these data support the notion that taurine prevents the hypertrophic effects of angiotensin ii by interfering with the translocation of either pkcalpha, pkcdelta, pkcepsilon or a combination of more than one of the isoforms. (the study was supported by a grant from taisho pharmaceutical co.) main final metabolites of l-cysteine in mammals are sulfate and taurine, and they are excreted in the urine. our previous studies in rats have shown that the ratio of urinary sulfate and taurine in rats fed diet containing sufficient methionine and cysteine is 10: 2-3. in the present study, we determined urinary sulfate and taurine in urine samples of 58 healthy japanese women after 12h starvation following usual meal. free (inorganic) and total (free ϩ ester) sulfate were determined with ion chromatography, and taurine by reversed-phase hplc after dabsylation. average excretions (micromols per mg of creatinine) were: total sulfate, 12.53 ϯ 3.85; free sulfate, 11.57 ϯ 3.69; ester sulfate, 0.96 ϯ 0.94; taurine, 0.78 ϯ 0.53; urea, 187.71 ϯ 66.13. the ratio of total sulfate and taurine was 10 : 0.62. this suggests that sulfate formation in humans is more dominant than taurine formation as in rats and this tendency is more evident in humans than in rats, which is in accordance with low cysteinesulfinate decarboxylase activity in humans. sum of sulfate and taurine excretions was significantly correlated with that of urea: correlation coefficient, 0.675. this indicates that sulfur metabolism in humans is in the state of sulfur equilibrium similar to that of nitrogen and reflects protein metabolism. h. yokogoshi 1 and h. oda 2 1 laboratory of nutritional biochemistry, school of food and nutritional sciences, the university of shizuoka, and 2 department of applied biological sciences, nagoya university, nagoya, japan the effect of taurine on hypercholesterolemia induced by feeding a high-cholesterol (hc) diet to rats was examined. when various amounts of taurine (0.25-50 g/kg) were supplemented to hc for 2 wk, serum total cholesterol gradually and significantly decreased in a dose-dependent manner, compared with the control (cholesterol free) diet group. by contrast, serum hdl-cholesterol was elevated by taurine supplementation. in the hypercholesterolemic rats fed the hc diet, the excretion of fecal bile acids and hepatic cholesterol 7α-hydroxylase (cyp7a1) activity and its mrna level increased significantly, and the supplementation of taurine further enhances these indexes, indicating an increase in cholesterol degradation. agarose gel electrophoresis revealed that, in hypercholesterolemic rats fed the hc diet, the serum level of the heavier vldl increased significantly, but taurine repressed this increase and normalized this pattern. significant correlations were observed between the time-and dose-dependent increases of cyp7a1 gene expression and the decrease of blood cholesterol concentration in rats fed the hc diet supplemented with taurine. these results suggest that the hypocholesterolemic effects of taurine observed in the hypercholesterolemic rats fed the hc diet were mainly due to the enhancement of cholesterol degradation and the excretion of bile acid. in vitro studies have shown that ammonia, which is responsible for neurological symptoms associated with hyperamonemia, causes a massive release of taurine from cultured cns cells and brain slices. in this study, taurine (tau) release was measured in vivo in rat striatum following direct application to the microdialysis tube of 60 mm ammonium chloride which renders the final ammonia concentration in the extracellular space of ϳ5 mm. various in vivo stimuli evoke taurine efflux either by opening osmosensitive anion channels and/or by a mechanism secondary to glu accumulation and its interaction with nmda or ampa receptors. the following compounds were coadministered with ammonia to distinguish between these mechanisms: anion/cation transport inhibitors -dids and furosemide, a glu transport inhibitor-pdc, and nmda and ampa/ka receptor antagonists dizocilpine and dnqx. ammonia stimulated tau accumulation in the microdialysates to ϳ250% of basal value. dids and furosemide moderately inhibited the effect of ammonia (furosemide by ϳ30%), albeit dids added alone induced massive accumulation of tau with a delayed onset as compared to ammonia. ammonia-dependent tau accumulation was increased by ϳ50% in the presence of pdc and reduced in an equal degree (ϳ35%) by dizocilpine and dnqx. none of the agents affected tau accumulation in the absence of ammonia. the results show that ammonia in vivo evokes tau accumulation both via anion channels, possibly secondary to cell volume changes, and in consequence of stimulation of both nmda and ampa/ka receptors. (supp. by a scsr grant no 4p05a05519 and cimo, the acad. of finland) biosciences department, university of hertfordshire, hatfield herts, u.k. the discovery in 1987 that endothelium-derived relaxing factor is nitric oxide (no) was followed a year later with reports that the cationic amino acid l-arginine is the physiological precursor for nitric oxide. it has since been established that the terminal guanidinium nitrogen of l-arginine is metabolised via a series of oxidation reactions resulting in no production, with citrulline being formed as a co-product. of interest was the parallel observation that uptake of l-arginine was enhanced in inos expressing cells and that this was due to de novo synthesis of carrier proteins. the precise signaling pathway that regulates the enhanced expression of these carriers has been the subject of intense studies in recent years. current literature suggests that activation of upstream signaling molecules such as protein kinase c may be critical. in addition, downstream kinases thought to be points of convergence for various signals originating from cell surface receptors have also been implicated. two of these downstream targets include the 42 and 44 kda forms of mitogen-activated protein kinase (mapk) and the stressactivated 38 kda mapk. it is worth noting however that the involvement of these different transduction pathways in the regulation of the induction of l-arginine transporters is not universal, and likely to be different from system to system. as a result there has been conflicting data on the relevance of these signaling proteins in inducing l-arginine transport in different cell. these issues will be discussed and the individual signaling pathways assessed on a cell type and species basis. moreover, the role of downstream signaling molecules will be examined in more detail, looking in particular at the critical dependency on the p38 mapk. this kinase currently exists in four different isoforms which are p38α, , γ and δ. the involvement of individual isoforms of p38 in enhancing the expression of carrier proteins for l-arginine will be discussed. gw274150 is an acetamidine derivative of heterosubstituted lysine which has been shown to have a marked selectivity for the human inducible nitric oxide synthase isoform (young et al. 2000. bioorg. med. chem. lett., 10: 6, 597-600) . the systems associated with transport of this compound have been investigated using the macrophage cell line j774. prior to each study, j774 cells were seeded in 96-well culture plates and allowed to adhere for 24 h in dulbecco's modified eagle's medium (dmem). transport studies were carried out using hepes buffered krebs solution (50 µl; 37°c) containing l-[ 14 c]gw274150 (1 µciml ϫ1 ) in the presence of either 0.1 mm or 0.025-1 mm unlabelled substrate. in parallel studies transport (1 µciml ϫ1 , 0.1 mm) was monitored in the presence of 1 mm excess of various other amino acids known to be substrates for distinct transport systems. time course experiments revealed that transport of 0.1 mm of l-[ 14 c]gw274150 occurred in a time-dependent manner and was linear for up to 5 min. in addition, uptake was only marginally dependent on extracellular na ϩ . kinetic studies revealed that transport was saturable, and michaelis-menten analysis revealed single affinity entry with an apparent k t of 0.31 mm and v max of 5.15 pmol·µg protein ϫ1 min ϫ1 . at 1 mm, 2-methylaminoisobutyric acid (meaib), lalanine, l-valine and -2-amino-bicyclo-(2,2,1)-heptane-2carboxylic acid (bch) caused little or no inhibition of l-[ 14 c]gw474150 (0.1 mm) uptake. in contrast, transport of l-[ 14 c]gw274150 was inhibited markedly by l-arginine, llysine, l-leucine, l-methionine, 6-diazo-5-oxo-l-norleucine (don) and l-glutamine. with the exception of l-arginine and l-lysine, the inhibition caused by the other substrates was critically dependent on extracellular na ϩ and was completely reversed when extracellular na ϩ was replaced with choline. in parallel kinetic inhibition experiments, transport of 0.1 mm l-[ 14 c]gw274150 was inhibited in a concentration dependent manner by l-arginine (ki ϭ 0.04 mm), l-leucine (ki ϭ 0.06), don (ki ϭ 0.18 mm) and l-glutamine (ki ϭ 0.13 mm). taken together, these data suggest that gw274150 may be transported, at least in part, by system y ϩ . however, the marked inhibition caused by l-leucine, l-glutamine and l-methionine, substrates for the relatively high affinity cationic amino acid transporter system y ϩ l, would suggest that this system may also contribute to the uptake of gw274150; if so, the monophasic substrate kinetics imply that the two systems handle gw274150 with similar affinity. other systems such as b 0,ϩ could be ruled out on the grounds that this transporter is critically na ϩ -dependent while uptake of gw274150 is largely (ϳ80%) na ϩ -independent. similarly, b 0,ϩ , another broadspectrum aminio acid transporter that may be capable of transporting gw274150 does not interact with l-glutamine and thus unlikely to be involved in transport of gw274150, at least in j774 cells. although a large number of different amino acid transporters have been identified on a molecular basis, some of themfunctionally described in mammalian cells -are still missing. in search of mammalian est sequences, which contain the signature of the aaap (amino acid/auxin permease) family, we identified a murine full length cdna, which encodes a membrane protein with 10-11 putative transmembrane domains. the transporter mrna is expressed in various murine tissues, including lung, heart and kidney. for functional characterization we used the xenopus laevis oocyte expression system and employed flux studies and electrophysiological analysis. oocytes injected with the crna showed an increased uptake of 3 h-l-alanine and 3 h-l-proline. detailed electrophysiological analysis revealed an electrogenic transport mode, independent of sodium and chloride ions. lowering the extracellular ph increased significantly substrate induced currents in crna injected oocytes. out of the 20 proteinogenic amino acids the transporter recognizes only small amino acids, such as gly, ala, pro and ser. distinct structural analogues of these amino acids also interact with the transporters substrate binding site. in conclusion, we describe the molecular and functional characteristics of the first electrogenic proton driven amino acid transporter of mammals. pharmacology department, dr. willmar schwabe gmbh, karlsruhe, germany it is now well established that transport of amino acid neurotransmitters (like glutamate, aspartate, gaba and glycine etc.) from and to the neurones is essential for their proper functioning. like in the case of other neurotransmitters, specific pre-and post-synaptic as well as vesicular transporters are involved in such processes. extensive efforts to clarify the mechanisms and processes involved in the control and/or proper functioning of the amino acid transporters are now, therefore, being made in numerous laboratories. such efforts have not only led to the identification of a few specific ligands and/or modulators of neuronal amino acid transporters, but also have started unravelling the complex and diverse processes regulating their functions. aim of this communication is to point out potential usefulness of some neuroactive constituents isolated from therapeutically used medicinal herbs for clarifying the mechanisms involved in neuronal amino acid transport. our interest in such studies was initially triggered by the observations made with hyperforin, i.e. quantitatively the major neuroactive component of hypericum perforatum extracts widely used for the treatment of mild to moderate depressive disorders. this acyl phloglucinol derivative not only modulate synaptic transports of biogenic amines but also of glutamate, aspartate and gaba. since it does not interact with any of the till now described transporters for these neurotransmitters, efforts were made to clarify the mechanisms involved in their observed effects (both in vitro and as well as in vivo). the results of the in vitro studies available to date strongly suggest that its effects on neuronal amino acid transport processes is mediated via some novel extracellular mechanism controlling the h ϩ (and/or other ionic) concentrations of neurones. these observations not only demonstrate that hyperforin represent a structurally and mechanistically novel class of therapeutically useful agent but also suggest that it could be useful tool for clarifying the complex mechanisms involved in the control of neuronal amino acid transport. these observations stimulated us to screen other putative psychoactive herbal extracts and their active constituents on neuronal amino acid transport and on the consequences of disturbances caused by malfunction of specific transporters. observations made with several such agents indicate that either modulation of mechanisms and/or processes involved in neuronal amino acid transport or reversal of pathologies caused by anomaly of transporter functions could be involved in their modes of actions. these observations reinforce our conviction that studies directed towards clarifying the effects of herbal constituents on neuronal amino acid transport might not only be a feasible way for identifying novel types of therapeutically interesting molecules but also could expedite our knowledge on these complex processes. glutamate-regulated sodium dynamics in cortical astrocytes: implications for cellular bioenergetics j.-y. chatton, p. marquet, and p. j. magistretti the mode of na ϩ entry and the dynamics of intracellular na ϩ concentration (na ϩ i ) changes consecutive to the application of the neurotransmitter glutamate were investigated in mouse cortical astrocytes in primary culture by video fluorescence microscopy. an elevation of na ϩ i was evoked by glutamate, whose amplitude and initial rate were concentration-dependent. the glutamate-evoked na ϩ increase was primarily due to na ϩ -glutamate cotransport. the rate of na ϩ influx decreased during glutamate application, with kinetics that correlate well with the increase in na ϩ i and which depend on the extracellular concentration of glutamate. a tight coupling between na ϩ entry and na ϩ /k ϩ atpase activity was revealed by the massive na ϩ i increase evoked by glutamate when pump activity was inhibited by ouabain. during prolonged glutamate application, na ϩ i remains elevated at a new steady-state where na ϩ influx through the transporter matches na ϩ extrusion through the na ϩ /k ϩ atpase. a mathematical model of the dynamics of na ϩ i homeostasis will be presented which precisely defines the critical role of na ϩ influx kinetics on the establishment of the elevated steady-state and its consequences on the cellular bioenergetics. indeed, extracellular glutamate concentrations as low as 10 µm approximately doubled the energetic demands of the astrocytes. department of biochemistry and molecular biology, faculty of biology, university of barcelona, spain in the last 5 years a new family of amino acid transporters composed by two different subunits has been defined. two heavy subunits (rbat and 4f2hc) and seven light subunits are known. rbat and the light subunits b0,ϩ at and y ϩ lat1 are responsible for the inherited aminoacidurias type i cystinuria, non-type i cystinuria and lysinuric protein intolerance, respectively. the heavy subunits are highly glycosylated type ii proteins, while light subunits are very hydrophobic unglycosylated membrane proteins, displaying a polytopic (generally 12 transmembrane domains) predicted structure. the specificity of the amino acid transport activity depends on the light chain expressed. this, together with its topology, indicates that the transport function mainly relies on the light subunits. i will summarize some of our current studies directed to the understanding of structure-function relationships of these heteromeric carriers, specially concerning their oligomeric structure and initial attempts to reconstitute them. ongoing work on the isolation of new rbat-associated light subunits and new b0,ϩ at-associated heavy subunits, which could also play a role in cystinuria, will also be discussed. department of pharmacology, joh. gutenberg university, mainz, germany mammalian cationic amino acid transporters (cats) catalyze the transport of basic amino acids through the plasma membrane. the cat family comprises at least five related carrier proteins (cat-1, -2a, -2b, -3 and -4) with cat-2a and -2b being splice variants. in humans, only the "old" members of the family have been characterized (hcat-1, -2a and -2b). hcat-1 and -2b exhibit high affinity for cationic amino acids and are sensitive to trans-stimulation, consistent with the classical system y ϩ . in contrast, hcat-2a is a low affinity carrier relatively insensitive to trans-stimulation. interestingly, hcat-2a and hcat-2b differ only in a region of 42 amino acids. cat-3, so far only identified in rat and mouse, exhibits also system y ϩ activity. however, the substrate recognition and maximal transport activity seems to differ from other y ϩ transporters. cat-3 expression has been reported to be restricted to the brain in adult animals. a cdna encoding for human hcat-4 has recently been isolated, however, the transport activity of hcat-4 has not been characterized. when optimally aligned, the amino acid sequence of hcat-4 shows only about 40% identity with the other hcat isoforms. in contrast, the amino acid sequences of hcat-1, -2(a or b) and -3 are about 60% identical. to elucidate which amino acids are responsible for the difference in the transport properties of the hcat proteins, we constructed chimeric proteins between hcat-1 and hcat-2a and performed site directed mutagenesis. using this approach, we identified two amino acid residues that are responsible for the different transport properties of hcat-2a compared to the high affinity cat-isoforms. to characterize the human cat-3, we cloned a cdna encoding hcat-3. when expressed in xenopus laevis oocytes, hcat-3 had a similar transport activity and affinity for l-arginine as hcat-1 or -2b. hcat-3mediated l-arginine transport was trans-stimulated and independent of extracellular na ϩ ions. expression studies demonstrated that hcat-3 is not only expressed in different regions of the human brain, but also in peripheral tissues. to investigate if hcat-4 also functions as an amino acid transporter, we measured the transport of cationic, neutral and acidic amino acids in xenopus laevis oocytes expressing hcat-4, but could not detect an transport activity for any substrate tested. a bright fluorescence could be detected in the plasma membrane of oocytes expressing hcat-4 with the green fluorescent protein attached to the c-terminus. therefore, hcat-4 might either need a complementary protein to function as an amino acid transporter or serve as a transporter for a yet unidentified substrate. renal amino acid reabsorption in immature and adult rats as a sensitive marker of heavy metal-induced nephrotoxicity (pt, cr, tl) institut für pharmakologie und toxikologie, klinikum der friedrich-schiller-universität jena, germany the effects of cis-platinum (cp; 0.6 mg/100 g b. wt. i. p.), sodium dichromate (cr; 1 mg/100 g b. wt. s. c.) and tl 2 so 4 (tl, 2 mg/100 g b. wt. i. p.) on renal amino acid excretion and plasma amino acid composition were investigated in 10-(both sexes) and 55-day-old (female) anaesthetised wistar rats (han : wist). on the basis of diuresis experiments on conscious rats (determination of urinary volume and protein excretion) the mentioned doses and times (1 st day after cr in both age groups and in 10-day-old rats after cp and 3 rd day after cp in adult rats; 2 nd [55-day-old rats] and 5 th -6 th day [10-day-old rats] after tl) were found out to be optimal for the characterisation of amino acid transport after heavy metal poisoning. interestingly, in conscious 10-day-old rats cr nephrotoxicity is not detectable after 1 mg/100 g b. wt. whereas all of the other experimental groups showed nephrotoxic effects of cr, tl and cp in conscious rats. urine volumes were lower, but not significantly, in anaesthetised immature rats, independently of the administered nephrotoxin. glomerular filtration rate (gfr) is significantly lower in 10-day-old rats compared to adults. after cp, cr and tl gfr is significantly reduced only in adult rats and age differences disappeared nearly completely. in principle the renal fractional excretion (fe aa ) of amino acids was distinctly higher in immature rats as a sign of lower amino acid reabsorption capacity. nevertheless, the amino acid plasma concentrations were relatively high in immature control rats. however, both cr and cp did not distinctly influence molecular cloning and functional characterization of ata3, a novel subtype of the amino acid transport system a medical college of georgia, augusta, georgia, u.s.a. recent molecular cloning studies have revealed that the amino acid transport system a consists of more than one subtype. two different system a subtypes, called ata1 and ata2, have been cloned and functionally characterized. ata1 is expressed primarily in the brain and placenta whereas ata2 is expressed ubiquitously. heterologous expression studies have shown that these two subtypes cannot be distinguished functionally based on substrate affinity nor substrate specificity. we have now cloned a third subtype of system a, designated ata3. it is expressed primarily in the liver. apart from the liver, detectable level of expression is noted only in the skeletal muscle. interestingly, ata3 can be easily differentiated from the other two subtypes of system a based on functional characteristics. we first isolated rat ata3 cdna from a skeletal muscle cdna library using rat ata2 cdna as the probe. rat ata3 consists of 547 amino acids and exhibits a high degree of homology in amino acid sequence to rat ata1 (47% identity) and rat ata2 (57% identity). interestingly, this new transporter also has a comparable degree of homology to sn1 and sn2, the two known subtypes of the amino acid transport system n. however, when expressed heterologously in xenopus laevis oocytes, rat ata3 transports α-(methylamino)isobutyric acid (meaib), a specific model substrate for system a, confirming that this transporter is definitely a subtype of system a. system n does not transport this system a model substrate. with two-microelectrode voltage-clamp technique, we have shown that exposure of rat ata3-expressing oocytes to neutral, short-chain aliphatic amino acids induces inward currents. the amino acid-induced current is na ϩ -dependent and phdependent. analysis of the currents with alanine as the substrate has shown that k 0.5 for alanine (i.e., concentration of the amino acid yielding half-maximal current) is 4.2 ϯ 0.1 mm and that the na ϩ : alanine stoichiometry is 1 : 1. subsequently, we have cloned the human homolog of rat ata3 from a liver cell line (hepg2) cdna library. human ata3 also contains 547 amino acids and shows 88% identity in amino acid sequence with rat ata3. the sequence identity of human ata3 with human ata1 and human ata2 is 47% and 57%, respectively. the homology of human ata3 with human sn1 and sn2 is also similar (56% and 51% identity, respectively). the gene coding for human ata3 contains 16 exons and is located on chromosome 12p13. in the human, ata3 is expressed almost exclusively in the liver. when expressed in mammalian cells heterologously, human ata3 mediates the transport of neutral amino acids, including meaib, in a na ϩ -dependent manner. interestingly, while characterizing the function of this clone, we have uncovered a unique feature of this system a subtype. human ata3 is capable of mediating the transport of cationic amino acids. in fact, the affinity of human ata3 for cationic amino acids is higher than for neutral amino acids. however, the human ata3-mediated cationic amino acid transport is na ϩ -independent. in this respect, ata3 is similar to transport system y ϩ l that also transports neutral amino acids in a na ϩ -coupled manner and cationic amino acids in a na ϩindependent manner. in contrast, ata1 and ata2 have not been shown to interact with cationic amino acids. in addition to this difference in substrate specificity, ata3 also differs from ata1 and ata2 in substrate affinity. ata1 and ata2 interact with meaib with a k t of ϳ0.3 mm whereas the affinity of ata3 for this model substrate is comparatively at least 20-fold lower (k t , ϳ8 mm). but, ata3 interacts with arginine with a k t value of 0.3 mm. since liver does not express any of the previously known high affinity cationic amino acid transporters, amino acid plasma concentrations. but in both age groups the administration of cr and cp significantly decreased amino acid reabsorption capacity (increase in fe aa ) as a sign of nephrotoxicity, most pronounced in adult rats after cp. on the other hand, after tl, the fe of amino acids was distinctly higher only in adult rats as a sign of lower amino acid reabsorption capacity and, thus, as a sign of higher nephrotoxicity. in immature animals fe aa was increased only for few amino acids. however, in both age groups tl administration significantly decreased plasma amino acid concentrations, more pronounced in immature rats. the investigation of renal amino acid handling confirmed: (1) cr, cp and tl were more nephrotoxic in 55-day-old animals compared to immature rats as could be demonstrated previously using other parameters for nephrotoxicity testing. (2) the extent of toxic effects of heavy metals on the kidney is related to the maturity of renal functions involved in the enrichment of the respective metal in renal tissue and in its toxicity mechanism. (3) changes in the fractional excretion of amino acids (reduction in renal amino acid reabsorption capacity, e.g. increase in fe aa ) and in amino acid plasma concentrations (especially decreases as a consequence of enhanced renal loss of amino acids) are early indicators of nephrotoxicity. (4) therefore, the determination of renal amino acid handling is a highly sensitive marker for nephrotoxicity testing, both in immature and in adult rats. the mammalian h ϩ /peptide cotransporter pept2 was initially identified in the brush border membrane of renal proximal tubular cells as a high affinity type ptr2-family member. here we describe the synthesis and functional analysis of novel high affinity inhibitors for pept2 that will be useful in further studies on structure and functions. starting from lys[z(no 2 )]-pro a series of different lysine-containing dipeptide derivates were synthesized and studied for interaction with pept2 based on transport competition assays in pichia pastoris yeast cells and in epithelial skpt cells, both expressing pept2. the twoelectrode-voltage-clamp technique in x. iaevis oocytes expressing pept2 was used to determine whether the compounds are transported electrogenically or block the uptake of dipeptides. synthesis and functional analysis of lys-lys derivates containing z(no 2 ) side chain protections provided a set of inhibitors that reversibly inhibited the uptake of dipeptides by pept2 with k i values as low as 10 nm. this is the highest affinity of a ligand of pept2 ever reported. moreover, based on the structure-function relationship we can conclude that the spatial location of the ε-amino protecting group in a lys containing dipeptide and its intramolecular distance from the alpha catom are key factors for the transformation of a substrate into an inhibitor of pept2. ata3 is likely to provide the major route for the uptake of arginine in this tissue. institute of pharmacology and therapeutics, faculty of medicine, porto, portugal the present study examined the nature and regulation of the l-dopa transporter in two functionally different clonal subpopulations of opossum kidney (ok lc and ok hc ) cells. the inward transfer of l-dopa was largely promoted through an energy-dependent and sodium-insensitive transporter, though a minor component (ϳ15%) was found to require extraceilular sodium. l-dopa uptake was insensitive to meaib, but competitively inhibited by bhc (ok lc , ic 50 ϭ 336 µm; ok hc , ic 50 ϭ 439 µm). l-and d-neutral amino acids and basic amino acids markedly inhibited l-dopa accumulation. l-dopa, lleucine, l-arginine, bhc or l-arginine plus bhc stimulated [ 14 c]-l-dopa efflux. the accumulation of l-dopa was significantly higher at an acidic ph, and incubation of cells with l-dopa (100 µm) resulted in marked intracellular acidification. modulators of pka, pkg, pkc and ptk failed to affect the accumulation of l-dopa. only the ca 2ϩ / calmodulin inhibitors inhibited l-dopa uptake. it is likely that system b 0,ϩ might be responsible for the sodium-dependent uptake of l-dopa in ok cells, whereas sodium-independent uptake of l-dopa may include systems b 0,ϩ and lat2, the activation of which results in trans-stimulation of l-dopa outward transfer. the trans-stimulation of l-dopa inward transfer by an imposed h ϩ gradient suggest that ok cells are provided with an l-dopa-h ϩ cotransport system. amino acids are essential nutrients for cell growth and maintenance. the essential amino acids arginine and lysine, are mainly transported via the cationic amino acid transporter 1 protein (cat1). the regulation of translation of the cat1 mrna during amino acid starvation was studied. an adaptive response to amino acid starvation and stress is a global decrease of protein synthesis, by phosphorylation of the translation initiation factor eif2a. translation of the transporter mrna increases when eif2a is phosphorylated, allowing synthesis of the essential for survival arginine/lysine transporter protein. the mechanism of increased translation of this mrna involves the induction of activity of a uorf-containing internal ribosomal entry sequence (ires). translation of the uorf and phosphorylation of eif2a are required for increased activity. we propose that eif2a phosphorylation triggers translational attenuation within the uorf, converting a relatively inactive, to a high activity ires. this study demonstrates that like yeast, mammalian cells have developed a sophisticated response to stress conditions: when expression of most genes decreases, synthesis of stress response proteins increases to support cell survival. amino acid transport, cell volume and the regulation of cell death f. lang, s. fillon, i. setiawan, p. lang, v. tanneur, d. häussinger, and s. bröer department for physiology, university of tübingen, germany cell volume regulatory mechanisms participate in a wide variety of cellular functions including regulation of epithelial transport, excitability, hormone and transmitter release, metabolism, migration, cell proliferation and apoptotic cell death. besides ion transport, polyols, betaine and glycerophosphorylcholine, cells utilize amino acids including taurine to balance extracellular osmolarity and regulate their volume. cells counteract shrinkage by uptake and swelling by release of amino acids including taurine. moreover, cell swelling stimulates synthesis and cell shrinkage favours breakdown of proteins which are osmotically less active than the sum of the amino acids thus generated. conversely, amino acid transport does influence cell volume. concentrative uptake of amino acids leads to cell swelling, amino acid release to cell shrinkage. through alterations of cell volume the amino acids participate in the regulation of protein metabolism. thus, concentrative amino acid transport inhibits and release of amino acids favours proteolysis. these mechanisms participate in the regulation of cell death. cd95 induced apoptotic death of jurkat t lymphocytes is paralleled by the release of taurine. the taurine release occurs with a delay of some 60 min following cd95 receptor triggering but immediately preceedes apoptic cell shrinkage and dna fragmentation. the signaling leading to taurine release is in large part elusive but requires at some stage activation of caspases. moreover, taurine release and apoptotic dna fragmentation are strongly inhibited by lowering of temperature. preloading of the cells with taurine retards cd95 induced dna fragmentation pointing to an active role of taurine in the regulation of apoptosis. peptide transporters of the ptr-family are integral plasma membrane proteins, that mediate the electrogenic protoncoupled transport of di-and tripeptides and peptide-like drugs across cell membranes. the physiological role of pept1, one member of this family in mammals, is mainly the uptake of small peptides into intestinal and renal tubular epithelial cells. in caenorhabditis elegans a homologue to mammalian pept1 is encoded by the pep-2 gene, which is expressed in the intestinal cells and a subset of sensory neurons in the head of the animal. to study the physiological role of the pep-2 transporter in vivo, a c. elegans pep-2 mutant was constructed. the animals deficient in pep-2 show a remarkable phenotype with pronounced signs of malnutrition, characterised by a delayed development, less eggs in the uterus, a smaller brood size and a prolonged mean life-span compared to wild-type animals. we rescued the phenotype by the expression of the wt pep-2 gene in the mutant. the observed starved phenotype in pep-2 mutants might be best explained by the reduced intestinal absorption of peptide bound amino acids that are required for protein synthesis and energy metabolism and provides the first direct evidence for the predominant role of the intestinal peptide transporter in amino acid absorption. adenosine is a potent vasodilator in many vascular beds and modulated tone via elevation of intracellular camp and/or release of nitric oxide (no). we have previously reported that adenosine (ado) stimulates l-arginine transport and no production in human cultured umbilical vein endothelial cells (sobrevia et al., j. physiol. 499, 135-140, 1997) , and here further characterise the signalling cascades. rt-pcr demonstrated that fetal endothelial cell possess mrna levels for a 2a , a 2b and a 3 -adenosine receptor subtype, whereas negligible levels were detected for the a 1 -receptor. adenosine (10 µm, 2 min) induced increases in l-arginine transport and no production were ca 2ϩ and camp independent and stimulated transport was abolished in cells depolarised with 80 mm k ϩ . whole-cell patch clamp experiments revealed that adenosine activated inward k ϩ currents, resulting in a membrane hyperpolarization and enhanced influx of the cation substrate l-arginine. adenosine induced l-arginine transport and no production were also abolished by inhibitors of tyrosine kinases (genistein), mek1/2 (pd98059, u0126) but unaffected by inhibitors of pkc (calphosin c) and pi-3 kinase (ly29002). these data suggest that adenosine induces membrane hyperpolarization by activating inward k ϩ currents, increasing the driving force for cationic amino acid influx via system y ϩ . the discovery of nocardicine a by aoki et al. and aztreonam showed that monocyclic -lactams, collectively known as monobactams, can have antibiotic activity. this activity is poor but compensated by the unique effect they can induce on certain microbial cell membranes. our quest for new non-conventional surfactants for various biomedical applications led us to synthesize bioactive compounds with structural similarities to nocardicins. we present here the preparation and the study of original trimodular biosurfactants of type i: spermine and amine oxidase induce a cytotoxic effect on multidrug resistant chinese hamster ovary cells e. agostinelli 1 , s. lord-fontaine 2 , e. przybytkowski 2 , and d. a. averill-bates 2 1 department of biochemical sciences "a. rossi fanelli", university of rome "la sapienza" and cnr, centre of molecular biology, rome, italy 2 department de chimie/biochimie and toxen (centre de recherche en toxicologie de l'environnement), université du québec à montréal, canada the occurrence of resistance to cytotoxic agents in tumor cells is a major obstacle to successful anticancer chemotherapy. multidrug resistance (mdr) is associated with several phenotypic alterations. cells with the mdr phenotype display decreased drug accumulation due to overexpression of pglycoprotein (p-gp), encoded by the mdr-1 gene, which acts as an energy-dependent pump involved in extrusion of drugs. we studied a new strategy to eliminate mdr cells using an enzyme, bovine serum amine oxidase, capable of forming cytotoxic products, h 2 o 2 and aldehyde(s), from polyamines (spermine). the involvement of both toxic products, formed by the bsao/spermine enzymatic system, in causing cytotoxicity was investigated in multidrug resistant chinese hamster ovary cells, ch r c5, at 37 and 42°c. we observed that hyperthermia, depletion of intracellular glutathione (by l-buthionine sulfoximine) and inhibition of glutathione s-transferase (by ethacrynic acid), sensitized ch r c5 cells to the cytotoxic effect of spermine enzymatic oxidation products. mdr cells showed no resistance to h 2 o 2 and aldehyde(s) relative to their drug-sensitive counterparts, auxb1 cells, in experimental conditions of: higher temperature, higher spermine concentration and longer incubation time. the inhibition of cellular detoxification systems led to increased cytotoxic effects of spermine enzymatic oxidation products on both mdr and sensitive cell lines. these results might be of great interest and suggest that toxic oxidation products formed from spermine and amine oxidase could be used in anticancer therapy, mainly against multidrug resistant tumor cells. [acknowledgements: this work was supported by cnr "target project on biotechnology", ministero della sanità tar these compounds present a hydrophobic part introduced by an ester or amide linkage with an aminoacid, a junction modulus which corresponds to -lactam, and a hydrophilic part which contains a triazole, well-known in pharmaceutical industry for its inhibitor effect against -lactamase. the compounds are synthesised from 2-hydroxymethyl-2methyl propionic acid in five steps. selective activation of one of the primary hydroxyl groups was accomplished by the formation of alkoxy tris(dimethylamino)phosphonium (atdp) salts 3 from the corresponding diol. treatment of 3 with excess potassium carbonate in refluxing anhydrous acetone yields the monobactams 4. activation by atdp salts followed by treat-ment with sodium azide and reflux in toluene gives the azido compound. the reaction with acetylenic derivatives allows to obtain the surfactants. the compounds show classical surfactant behavior and the evaluation of their biological properties give evidence for their antibacterial and antiviral activity, which corresponds apparently to antiprotease activity. a prodrug approach to glutathione derivatives with in vitro antiparasitic activity department of chemistry and materials manchester, faculty of science and engineering, metropolitan university, manchester, u.k. the potential chemotherapeutic activity of peptides are lost in many cases in vitro, due to their inability to cross cell plasma membranes. the recent identification of a series of glutathione diesters with high antiparastic activities in vitro against t.b.brucei (african sleeping sickness) lead us to investigate the determinants associated with their activity. a qsar study on some twenty-five diester derivatives against t.b.brucei and t.b. rhodesiense lead us to conclude that the mechanism of action of these compounds is related to membrane penetration and hydrolysis, controlled by hydrophobicity and steric factors. a hplc and sensor study have confirmed the de-esterified diacid as the active agent of these prodrugs. dietary taurine prevents oxidative stress and morphological alterations in the retina of diabetic rat f. franconi 1 , m. a. s. di leo 2 , s. caputo 2 , n. gentiloni silveri 2 , and g. ghirlanda 2 1 department of pharmacology, university of sassari, and 2 department of internal and geriatric medicine, catholic university, rome, italy diabetes mellitus can cause various complications including retinopathy, which is the earliest and most common complications of diabetes mellitus, affecting 90% of diabetics and progressing to blindness in about 5%. considerable evidence implicates oxidative stress in the pathogenesis of diabetic retinopathy. in fact, hyperglycemia generates reactive oxygen species and free radical defense is reduced in diabetic patients. thus, the prevention of oxidative stress may have important implications for pharmacological attempts to prevent diabetic retinopathy. at this regard, it has been found that taurine, a semi essential amino acid with antioxidant activity, is decreased both in type 1 and type 2 diabetes mellitus. moreover, taurine seems to have a peculiar role of taurine in terms of cellular physiology and pathophysiology of the retina. among others, taurine is thought to produce important physiological effects through osmoregulation, calcium modulation and antioxidant effects. therefore, we examined the effect of dietary chronic (4 months) taurine (2% and 5%) supplementation in diabetic rats in comparison with vitamin e (200 and 500 ui). dietary taurine supplementation, for 4 months, does not influence conjugated dienes (cd), lipid peroxides (lp) and na/k atpase activity in the retina of non diabetic rats. using rats streptotozocin (stz) induced diabetes of 4-month duration, we found that cd, lp are significantly increased and they remained elevated for 4 months. while, the na/k atpase is significantly decreased during the whole experimental time (4 months). moreover, an inverse correlation has been found among the cd and lp and atpase activity. in the retina of stz rats, these biochemical alterations are accomplished with marked profound morphological changes. in stz rats, taurine enriched diets decrease the lipid peroxidation and preserve the atpase activity, being 5% taurine more effective than 2% diets. the morphological examination reveals that in rats feed with 5% taurine no proliferative changes are present. moreover, the beneficial effects of taurine are more marked than of those of vitamin e. these results and previous findings encourage new investigations to evaluate the efficacy of taurine as an adjunctive agent ch ch 3 (ch 2 ) n xco iran applicated be (500 mg/kg -10 days) and the third -control. enzyme activities were determined spectrophotometrically in brain homogenate. results: polyamine oxidase activity decreased significantly lower dose of be didn't induce any significant change in diamine oxidase activity gaba-transaminase activity increased significantly (p ͻ 0.005; p ͻ 0.001) and dose dependently upon be treatment we have been examined the effects of propofol, taurine and propofol combined with taurine on free intracellular amino acid (aa) profiles, superoxide anion formation (o 2 ϫ ), hydrogen peroxide production (h 2 o 2 ) and released myeloperoxidase activity (mpo) in polymorphonuclear leucocytes (pmn). propofol led to significant changes in pmn free taurine, glutamine, glutamate, aspartate, methionine, basic, neutral (naa) and branched chain amino acid concentrations. exogenous taurine reduced pmn naa while increasing intracellular taurine. taurine supplemented to propofol significantly reversed the changes in taurine, naa and alanine only. regarding pmn immune functions propofol significantly decreased o 2 ϫ , h 2 o 2 formation and mpo. taurine decreased o 2 ϫ and h 2 o 2 production, while increasing released mpo. when propofol and taurine were combined they appeared to by reacting tyrosine with 1-nitroso-2-naphthol in the presence of nitric acid 1-2-benzyo-8-(alanyl)-3-phenoxazone (blp) an analog of actinomycin d is produced. the structural similarity of blp to actinomycin d prompted the national cancer institute (nci) to investigate its antitumor activities. the nci investigations revealed that blp exhibits growth inhibitory effects on various cancer cells and as a result blp has received the u.s. patent from the u.s. patent office. the purposed of this investigation was to synthesize similar benzo phenoxazone derivative by reacting 1-nitroso-2-naphthol with 4-(α-hydroxy -methylaminopropyl)phenol in the presence of nitric acid. during the study, it was found out that 1,2-benzo-3phenoxazone derivative is not produced but a hydrogenated form of 1,2-benzo-3-phenoxazone which is probably 1,2-benzo-8-(α-hydroxy -methylaminopropyl)-3-hydroxyphenoxazine (bhmhp) which has been suhhested from mass spectra obtained by electron ionization, ei, chemical ionization, ci and electro-spray ionization, esi, methods. 1 bhmhp was screened against various cancer cell lines by nci and has shown promising effect against three (3) breast cancer cell lines: mda-mb-435, mda-n and hs-578 t. the 50% growth inhibitory (gi 50 ) concentrations for these three cell lines were 4.60 ϫ 10 ϫ6 , 4.62 ϫ 10 ϫ6 and 5.74 ϫ 10 ϫ6 molar respectively. a. bocheva 1 and t. pajpanova 2 1 institute of molecular biology, bulgarian academy of sciences, and 2 institute of physiology, bulgarian academy of sciences, sofia, bulgariathe histamine is an endogenous substance with neurotransmitter and neuromodulator functions in the organism. its antagonists are used in the therapy of allergic diseases and inflammatory reactions and as antiulcer drugs.the limited potentialities of the antihistamine therapy together with the increasing number of the people suffering from allergic diseases give rise to the design and synthesis of new histamine analogues as a perspective area in the chemistry of therapeutic drugs.additionally, compounds containing the guanidine, oxyamino and sufonamide moieties are known to elicit a variety of pharmacological responses and are present in several marketing drugs or drug candidates.on the other hand, similar compounds, being a part of bigger structures (for instance peptides), can imitate the molecules of already known at ii-receptor antagonists.having in mind these data we aimed to synthesize new analogs of histamine containing sulfo-and oxy-guanidino groups with common formula: a. bocheva 1 , s. pancheva 2 , and t. pajpanova 2 1 institute of physiology, bulgarian academy of sciences, and 2 institute of molecular biology, bulgarian academy of sciences, sofia, bulgariathe problem of the efficient therapy of pain is important not only from clinical but from social and economic point of view. the great achievements in medicine are connected with the research on the development of antinociceptive drugs.melanocyte-inhibiting factor (mif) is a tripeptide (pro-leu-gly-nh 2 ) that was discovered in hypotalamus.the mif-1 exerted a weak analgesic effect. the synthesis of non-protein amino acids and their incorporation into biologically active peptides might become a powerful method for the design and development of modified analogues of natural peptides. having in mind these data we synthezied a number of new mif-analogues, containing unnatural amino acids such as cav, slys, sleu, slle and snie and in vivo experiments were performed to study their action on the nociception. the changes in nociceptive effects were examined in male wistar rats by the tail-flick (tf) and hot-plate (hp), as well as, the randall-seitto paw-pressure tests. the peptides were applied intaperitoneal (i.p) injection at a does 1 mg/kg. the results show that the newly sinthesized analogues exert an antinociceptive effects in all tests used. naloxone at a dose 1 mg/kg (i.p) antagonized the antinociceptive effects of mif-analogues. the interaction between platelets and fibrinogen is known to be mediated by the intergrin gp iib/iiia. the arg-gly-asp (rgd) sequence located on fibrinogen and other proteins of blood and extracellular matrix is the minimum requirement for cell attachment and adhesion. it has been found that peptides containing the rgd sequence can effectively inhibit the binding of fibrinogen to gp iib/iiia. in addition aspirin has been shown to be beneficial in the treatment of stable and unstable angina, acute myocardial infraction. aspirin acetylates and inhibits the enzyme cyclooxygenase, the first enzyme involved in thromboxane a 2 (txa 2 ) synthesis, an activator of platelet aggregation and adhesion.we have already reported that the combination in the same molecule of dipeptide amides, containing amino acid(s) of rgd sequence, with salicylic-residue 2-ro-c 6 h 4 -coϳ, {where rϭh or ch 3 co} at their n-terminal amino group have shown inhibitory activity on human platelet aggregation. continuing this research project on salicyl-peptides we have synthesized a series of rgd analogs, incorporating salicylic acid derivatives, by conventional solution techniques and/or by solid phase. the synthesized rgd analogs were identified by ir, nmr and es-ms spectra and tested for inhibitory activity on human platelet aggregation in vitro, by adding common aggregation reagents (collagen, adp, thrombin) to citrated platelet rich plasma (prp). platelets were obtained from venous blood of healthy donors and the prp was isolated by centrifugation at 200 g for 5 min at 37°c. the aggregation was determined using a dual channel electronic aggregometer. malonyl dialdehyde (mda) production was measured using thiobarbituric acid reagent. in order to confirm these results, flow cytometry with monoclonal antibodies against gpib, gpiib/iiia, gpiiia and gmp140 was used. the ic 50 values of the synthesized and tested compounds, as well as their mda production and flow cytometry results will be discussed. amino acids have a long tradition as building blocks, chiral auxiliaries and/or ligands in advanced organic synthesis and catalysis. at dsm an enzymatic kinetic resolution process has been developed, based on an aminopeptidase catalyzed stereoselective hydrolysis of racemic amino acid amides to form a mixture of l-amino acid and unchanged d-amino acid amide.several small peptides currently are under investigation as possible anti-tumor agents. neuropeptides such as substance p (sp) and neuropeptide y (npy), have been studied for their ability to prevent tumor growth or the proliferation of several cancer cell lines. these neuropeptides have been investigated for their effect to prostate cancer, small cell lung cancer (sclc) and breast cancer. the synthetic sp analog [d-arg 1 , d-phe 5 , d-trp 7,9 , leu 11 ]sp (antagonist d) and the c-terminal analog [arg 6 , d-trp 7,9 , mephe 8 ]sp 6-11 (antagonist g) inhibit sclc cell proliferation in vitro and in vivo, while the analogs [glp 6 , glu(bu t ) 11 ]sp 6-11 and [glp 5 , glu(bu t ) 11 ]sp 5-11 showed significant inhibition in the proliferation of the cancer cell lines hela and t47d.in the present study the c-terminal analogs of sp [glp 6 , d-trp 7 , glu(bu t ) 11 ]sp [6] [7] [8] [9] [10] [11] (1), [glp 6 , d-trp 7,9 , glu(bu t ) 11 ]sp [6] [7] [8] [9] [10] [11] (2), [glp 6 , d-trp 7,9 , mephe 8 , glu(bu t ) 11 ]sp 6-11 (3), [glp 6 , d-trp 7 , mephe 8 , glu(bu t ) 11 ]sp 6-11 (4), [glp 6 , trp 7 , mephe 8 , glu(bu t ) 11 ]sp 6-11 (5), [glp 6 , mephe 7 , d-trp 8 , glu(bu t ) 11 ]sp 6-11 (6), [glp 6 , d-trp 7 , mephe 8 , glu(bu t ) 11 -oh]sp 6-11 (7), [glp 6 , d-trp 7 , cys(acm) 11 -oh]sp 6-11 (8), [glp 6 , d-trp 7 , mephe 8 , cys(acm) 11 -oh]sp [6] [7] [8] [9] [10] [11] (9), [glp 6 , d-trp 7,9 , mephe 8 , cys(acm) 11 -oh]sp 6-11 (10) have been synthesized and tested for their antineoplastic properties in several cancer cell lines. they were also examined for their cytotoxicity to normal cells.the analogs 1-6 are peptide amides whereas the analogs 7-10 are peptide acids. they were performed using the stepwise synthesis either in solution, using the method of mixed anhydrides with carbonic acids or in spps using the fmoc/bu t methodology. the fragment condensation method in solution, using phosphonium reagents, such as pybop, was also applied. the analogs were purified (hplc) and identified (ft-ir, es-ms, 1 h-nmr).the antineoplastic properties of the analogs were studied using sister chromatide exchange (sce) and proliferation rate index (pri). as it is known the sce method is an indicator of dna damages or its repair mechanism, while the method of pri is a sensitive marker of cytotoxicity. the experiments were carried out using cultured human lymphocytes from healthy donors and these results will be discussed.semiempirical quantum chemical investigation of some thymidine derivatives modified with amino acids and peptides at 3ј, 5ј-positions j. velkov 1 , i. stankova 1 , a. ivanova 2 , and a. tadjer 2 1 department of chemistry, south-west university "neophit rilski", blagoevgrad, and 2 department of chemistry, sofia university "st. kl. ohridsky", sofia, bulgaria optimized geometry and electron charge distribution for some thymidine derivatives (3ј,5ј-bis-o-n-α-benzyloxycarbonyl-alanyl-, 3ј,5ј-bis-o-n-α-benzyloxycarbonyl-valyl ,3ј,5ј-bis-o-n-α-benzyloxy-carbonyl-glycyl-glycyl-glycyl,3ј,5јbis-o-n-α-benzyloxycarbonyl-phenylalanyl,3ј,5ј-bis-o-n-αbenzyloxycarbonyl-glycyl) were calculated at the semiempirical (am1) level. the choice of method is limited by the molecular size. in addition, the differences between the ground state energy of the compounds and that of the hydrolysis reaction intermediates were compared to the experimentally found stability towards hydrolysis.with a few notable exceptions, attempts to crystallise integral membrane proteins have failed due to the difficulties in finding appropriate conditions for proteins that have both hydrophobic and hydrophilic domains. thus structural information is largely limited to predictions of secondary structure from the amino acid sequence and computer modelling, neither of which can as yet give high resolution detail. thus alternative approaches are required, and one that we have employed is to look at the substrate binding/transport characteristics of compounds and predict what features the binding site might have. the membrane transport protein that we are interested in is the proton-coupled di/tri-peptide transporter, which has a wide range of natural substrates and is known to transport therapeutically important non-peptides such as ᮀ-lactam antibiotics and angiotensin converting enzyme inhibitors.the initial question that interested us was what makes a di/ tri-peptide a substrate, but not an amino acid? while the obvious answer is the peptide bond, studies with 'space mimic' compounds (which have the space filling properties of a dipeptide but no peptide bond) gave the surprising result that the peptide bond was not essential for binding and translocation. although these space mimics had n and c termini, studies from our laboratory and others have shown that the presence of free amino or carboxyl groups are not a prerequisite for binding or translocation either. this leaves the question of what does distinguish a pept1 substrate from a non-substrate?computer modelling of a large number of pept1 substrates has allowed the development of a substrate template, whereby potential substrates can be scored according to their predicted binding affinity. from this it is clear that it is a sum of energies derived from a number of substrate-transporter interactions that determine binding affinity, including the n-and c-termini, the peptide bond components and the substrate side-chain groups. further studies aim to refine this model through the complimentary approaches of novel substrate design and sitedirected mutagenesis of the transporter protein.why are we interested in this? a large number of promising therapeutic compounds are found to have little or no bioavailability. compared with most membrane transporters pept1 has a wide range of potential substrates, and amongst its non-peptide substrates are a range of peptidomimetic therapeutic compounds. the recent finding that a peptide bond is not a prerequisite for transport opens up the possibility of designing prodrugs to be substrates for pept1, and this has found to be an effective strategy for example with the antiviral drug valacyclovir.(we thank the wellcome trust for their generous support.) nuklearmedizinische klinik und poliklinik der technischen universität münchen, germanyaim: the high amino acid metabolism of tumor cells allows tumor imaging with radiolabeled amino acids as 11 c-methionine (met) by positron-emission-tomography (pet). however in recent experimental and clinical studies met uptake was also found in inflammatory tissue thus leading to false positive results. the aim of the study was to compare [ 18 f]fluoroethyltyrosine (fet), a new amino acid analogue, with met to assess their suitability for differentiating between tumor cells and inflammatory cells in vivo and in vitro.methods: popliteal lymph nodes of balb/c and dba/2 mice were stimulated either by streptocotocin (stz), causing chronic lymphadenitis, or by concanavalin a (con a), causing in acute lymphadenitis. tumor infiltrated lymph nodes were induced by inoculating cells from a lacz transfected t-cell mouse lymphoma line into the footpads of syngenic dba/2 mice. the uptake of met and fet was determined quantitatively in tumor infiltrated and inflammatory lymph nodes as well as in the lymph nodes of untreated mice. in vivo imaging of tracer uptake in mouse lymph nodes was performed using a high resolution (2.4 mm) small animal pet (madpet). in vitro the uptake of the amino acids met and fet was investigated in different cells, such as sw707 human colon carcinoma cells and c6 rat glioma cells, stimulated human lymphocytes and macrophages. about 5 ϫ 10 5 cells of each cell line were incubated in a buffered medium containing either different concentrations of unlabeled amino acids or con a (stimulation of lymphocytes) or the transport inhibitors 2amino-norbornane-carboxylic acid (bch, l-system), α-(methylamino)-isobutyric acid (meaib, a-system) or l-serin (asc-system). 0.37 mbq of each amino acid tracer were added and incubated. uptake was stopped by using ice-cold pbs, cells were washed three times and uptake was analyzed.results: in tumor infiltrated lymph nodes uptake of both tracers was higher than in control lymph nodes. met showed an increased uptake in both lymphadenitis models, whereas fet did not accumulate significantly. met and fet uptake in tumor infiltrated lymph nodes was also seen in madpet images, however inflammatory lymph nodes could only be detected in met images.the amount of tumor uptake was different in the various cell types investigated. c6 cells showed the highest uptake of all cells investigated and a slightly lower uptake was found in sw707 cells. in con a stimulated lymphocytes, the uptake of fet was negligible, while met uptake was significantly higher than in both tumor cell lines. since bch reduced the uptake of fet and met to approximately 10%, fet seems to be also predominantly transported into tumor cells by the l-system. the results indicate, that fet appears to differentiate between tumor and inflammatory tissue, as a result of the low uptake of fet in inflammatory cells. nuklearmedizinische klinik und poliklinik der technischen universität münchen, germanyover the past few years numerous studies have documented the high diagnostic accuracy of positron emission tomography (pet) using the glucose analogue f-18-fluordeoxyglucose (fdg) for detection and staging of malignant tumors. a significant limitation of fdg-pet, however, is that increased uptake is not only observed in malignant tumors but also in activated inflammatory cells. due to the high glucose utilization of the normal brain and the lower protein synthesis in the normal gray matter the radiolabelled amino acid c-11-methionine (met) gives higher contrast between brain tumors and normal tissue than fdg-pet. rapid uptake of met has been documented for several malignant tumors like gliomas, lung cancer, bladder cancer and malignant lymphomas since amino acid transport and protein synthesis are generally increased in malignancies. the application of met-pet however has been limited by the short half life of the radioactive label c-11 (20 min) in contrast to f-18 (110 min). amino acid analogous labeled with f-18 like f-18-fluoro-α-methyltyrosine (fmt), f-18-fluoro-ethyltyrosine (fet), f-18-fluoro-phenylanaline, f-18-fluore-proline will allow a more widespread application of amino acid pet in oncology. an other amino acid analogue i-123-iodo-α-methyltyrosine (imt) is of clinical interest because the radionuclid i-123 allows it applicability for single-photoemission-computer-tomography (spect). the uptake of the amino acid analogues can only be regarded as a measure for the increased amino acid transport in the tumor cells because they are not incorporated into proteins. clinical data show that radiolabelled amino acids that are only transported into the cells are not inferior to those that enter protein synthesis. this tracers may also help to differentiate tumor lesions from inflammatory lesions when the expression of the transport systems for amino acids in tumor cells and inflammatory cells is different.lysinuric protein intolerance: understanding the pathophysiology of a multi-system disorder of dibasic amino acid transport m. p. sperandeo 1,2 , v. fiorito 2 , a. pietrosanto 2 , a. pepe 2 , g. andria 2 , and g. sebastio 2 1 telethon foundation, rome, and 2 department of pediatrics, federico ii university, naples, italy lysinuric protein intolerance (lpi; mim 222700) is an autosomal recessive disease, mainly found in finland and italy. clinical findings of lpi include: vomiting, diarrhea, failure to thrive, hepatosplenomegaly, osteoporosis, episodes of coma, and mental retardation. a life-threatening lung involvement (alveolar proteinosis) and renal insufficiency were also reported. metabolic derangement of lpi includes: reduced intestinal absorption of cationic amino acids (lysine, ornithine, arginine, caa), increased renal excretion of caa and dysfunction of the urea cycle leading to hyperammonemia and orotic aciduria. most of the clinical findings cannot be explained by a selective deficiency of amino acid transport, as indeed observed for cystinuria (mim 220100), a cognate disease of lpi. the molecular basis of lpi resides in an abnormal caa carrier functioning at the level of basolateral membrane of epithelial cells in the intestine and the kidney. caa transport is mediated by y ϩ l system, that is exerted by heterodimers consisting of the 4f2 heavy chain (4f2hc) and a light chain represented by either the solute carrier family 7a, member 6 (slc7a6) or 7 (slc7a7). after excluding the 4f2hc as the causative gene of lpi, we identified slc7a7 as the lpi gene and characterized mutations in twenty-five patients from 21 families (16 italian, 2 japanese, 1 moroccan, 1 greek, and 1 pakistani; 34 independent alleles) affected by lpi. thirty-two of the 34 independent alleles (94.1%) were characterized and fourteen mutations were identified. only five mutations (namely 1625insatca, w242x, 1425delctct, ivs3 ϩ 1gaea, s386r) were identified in more than one independent family. most mutations are located in the slc7a7 coding region, except for two splicing mutations. the pathogenesis of some clinical findings of lpi, namely alveolar proteinosis and renal involvement, remains mostly unknown. we are currently investigating the role of slc7a6 gene in lpi, which, in addition to slc7a7, is responsible of the y ϩ l activity. in fact, the regulation of the y ϩ l system, exerted by either 4f2hc/ slc7a76 or 4f2hc/slc7a7, is still unknown. hypothetically, the activation of 4f2hc/slc7a76 in all tissues might be the "simple" way to a lpi gene-therapy.[acknowledgements: m. p. s. is supported by telethon-italy (grant n.29cp) and is an assistant telethon scientist.] pre-eclampsia (pe) is a potentially life threatening complication of pregnancy and is one of the leading causes of maternal and fetal morbidity and mortality. pe is associated with endothelial cell dysfunction and inadequate placental perfusion. fetal plasma l-arginine levels are decreased in pe and there is controversy as to whether nitric oxide (no) production is altered. we have investigated whether the kinetics of l-arginine transport via system y ϩ and no production are altered in fetal umbilical vein endothelial cells (huvec) from pe pregnancies. kinetics of l-arginine transport were similar in huvec isolated from normal, preterm and pe pregnancies, however nethylmaleimide inhibited transport in normal but not pe huvec. basal and histamine-stimulated no production was similar in normal and preterm huvec, whereas pe increased basal (25 ϯ 5 vs 5.3 ϫ 3 pmol/10 8 cell/5 min) and histaminestimulated (70 ϯ 12 vs 20 ϯ 5 pmol/10 8 /5 min) no production. whole-cell patch clamp measurements revealed similar inward rectifying k ϩ currents in normal and pe huvec, with resting membrane potentials of ϫ65 ϯ 4 and ϫ80 ϯ 18 mv in normal and pe huvec, respectively. increased enos activity in pe endothelial cells may serve as a compensatory mechanism to counteract the hypertension observed in pe, however, elevated no production is apparently not associated with enhanced larginine transport. department of pharmacology, university of cambridge, u.k.over the past years, concerns have heightened over the escalating numbers of pathogenic microorganisms that are resistant to multiple antibiotics. this phenomenon poses major problems in the treatment of patients with hospital or community-acquired infections caused by bacteria, yeast, fungi and parasitic organisms. particularly intriguing are the so-called multidrug transporters, which have specificity of compounds with very different chemical structures and cellular targets. this lecture will focus on the molecular properties of the atpbinding cassette multidrug transporter lmra in the lactic acid bacterium lactococcus lactis. lmra is a close homolog of the human multidrug resistance p-glycoprotein, overexpression of which is one of the major causes of resistance of human cancers to chemotherapy. surprisingly, lmra can even substitute for pglycoprotein in human lung fibroblast cells. recent biochemical and pharmacological studies on lmra suggest that the protein may operate by a two-cylinder engine mechanism to transport amphiphilic drugs from the inner leaflet of the plasma membrane. this mechanism will be discussed in more detail. bone and bone marrow are important sites of metastasis formation in breast cancer; so, we studied the level of bone sialoprotein (bsn) and fibronectin (fn), two key connective tissue antigens, in patients with metastatic breast carcinoma. our data reveled that bsn have a statistically significant association with bone metastases in that disease. fn level was also significantly changed in metastatic breast carcinoma when compared to the non metastatic cases. kharkov national university, radiophysical department, chair of molecular and applied biophysics, kharkov, ukraine * present address: institute of cell and molecular biology, university of edinburgh, edinburgh, scotland, u.k.in the work the temperature dependencies of dielectric parameters of human serum albumin (hsa) and fibrinogen solutions (0.15 m nacl, ph 7.2) were obtained in the temperature interval 5-50 c degrees. the measurements of the dielectric parameters were carried out at the frequency of 9.2 hhz, i.e. in the range of free water molecules dispersion. in contrast to dependencies for poor solvent, temperature dependencies of dielectric parameters for protein solutions are of nonmonotonous character; they have a number of peculiarities in the temperature ranges of 8-10, 22-24 and 34-36 c degrees. this fact means that at these temperatures redistribution of free and bound water in protein-water system occurs due to structural changes in protein molecules. the dependencies of hydration of hsa and fibrinogen on temperature were obtained as well.in the work the mechanism of temperature changes of spatial organisation of protein molecules was proposed. perhaps, this mechanism is responsible for maintenance of thermal stability of the functionally active conformation of native proteins. as peculiarities on temperature dependencies of dielectric parameters of solutions of globular (hsa) and fibrillar (fibrinogen) proteins were in the same temperature regions, one may to assume that the mechanism of proteins thermal stabilisation in physiological temperatures interval has a general character. laboratory of cell pharmacology, university of leuven, medical school, campus gasthuisberg (o&n), leuven, belgium n-pomc was purified from conditioned medium of att20 cells using a sequence of concentration, fractionation by ion exchange, rp-hplc and gel-filtration. twenty isoforms of n-pomc, for both 11 and 13 kda, were identified by means of mass spectrometry and n-terminal sequencing. these isoforms are assumed to be pomc1-74 or pomc1-95 with heterogeneous glycosylation.the n-pomc isoforms were tested on prolactin (prl) gene expression and lactotroph mitosis in pituitary cell aggregate cultures. prl mrna content was quantified by means of real time rt-pcr. three 11 kda n-pomc fractions enhanced prl mrna levels by 33-36%, while all other isoforms were inactive. this effect was abolished by immunoneutralization with n-pomc monoclonal antibody. only one fraction stimulated lactotroph proliferation (38.2 ϯ 7.5%) as assessed by brdu incorporation in prl-immunoreactive cells. several (but not all) 13 kda n-pomc fractions stimulated prl mrna level and lactotroph mitosis. on the other hand, all 11 and 13 kda isoforms activated the mc-3 and mc-5 receptor in cell lines in which these receptors were transfected. thus, att20 cells produce various n-pomc isoforms, only a part of which display an effect on prl mrna expression. even fewer isoforms affect lactotroph proliferation. since all isoforms activate the mc-3 and mc-5 receptor, it is suggested that the effect of the few isoforms on lactotrophs is mediated by (a) different receptor(s). are widely prescribed for the treatment of mild to moderate depression and the putative antidepressant constituent is probably hyperforin. in this study the effect of hyperforin was investigated on the release of neurotransmitter amino acids.coronal cortical slices (400 µm) were cut and perfused with gassed (95% o 2 , 5% co 2 ) acsf at 37°c. two-minute samples of perfusate were collected and aspartate and glutamate were assayed by hplc. potassium-and veratridine-stimulated release was elicited by administering 2 pulses of k ϩ (60 mm) or veratridine (20 µm) 30 minutes apart.in control experiments the second k ϩ pulse elicited glutamate release which was 80% of the first pulse. hyperforin (5 µm) perfused for 30 minutes prior to, and during, the second k ϩ pulse significantly increased glutamate release to 170% (p ͻ 0.001, n ϭ 6-8). release elicited by the second veratridine pulse was 70% of the first pulse for both glutamate and aspartate. hyperforin (5 µm) increased this release to the second pulse to 160% and 130% respectively (p ͻ 0.001, n ϭ 6-8). when perfused on its own for 30 minutes, hyperforin (5 µm) increased the basal release of glutamate (p ͻ 0.001, n ϭ 4-5).in conclusion, the increase in the release of neurotransmitter amino acids observed following hyperforin is possibly mediated through a facilitatory action on voltage-operated ca 2ϩ or na ϩ channels.glucagon-like peptide-1 (7-36) amide (glp1) is the main product of the glucagons gene expression in intestinal l cells into the cirulation in response to the ingestion of food and is the most potent stimulator of glucose-induced insulin secretion. glp1 receptors have also been detected in discrete areas of rat brain and intracerebroventricular glp1 has been shown to inhibit feeding in fasted rats. in this study hplc techniques were employed to evaluate the effects of glp1 on serotonin (5-ht) and γ aminobutyric acid (gaba) metabolism in rat brain. glp1 (0.5 µm) produced a significant decrease in levels of 5-ht by 20% after 15 minutes of incubation with combined hypothalamus and brain sterr. synaptosomes. levels of 5hydroxyindolacetic acid (5-hiaa), the principal metabolite of 5-ht, and tryptophan the amino acid precursor of 5-ht, were also decreased significantly by 21% and 37% respectively. gaba and its amino acid precursor glutamic acid were both measured at the same conditions as above, but a precolumn derivatization hplc technique was used. the increase in levels of gaba (14%) and glu (6%) by glp1 was not significant.the results suggest that decreased synaptosomal levels of 5-ht and 5-hiaa caused by glp1 are due to diminished availability of typtophan by the peptide. in experimental model of iron overload we obtained the following results: the concentration of carbonyl groups tended to increase, while mda level significantly increased after feso 4 treatment (1.66 ϯ 0.25 vs control 1.51 ϯ 0.50 µmol/mg prot.) and (2.13 ϯ 0.5 vs control 1.3 ϯ 0.3 nmol/mg protein p ͻ 0.01) respectively. it was associated with significantly increased iron content (0.89 ϯ 0.23 µg/mg prot. vs control 0.49 ϯ 0.17 p ͻ 0.001). it is clear that oxidative stress occurs in experimental iron overload, if sufficiently high levels of iron within hepatocytes are achieved. in group treated with feso 4 and spermine, iron content was significantly decreased (0.36 ϯ 0.07 p ͻ 0.01 compared with fe treated only) and carbonyl group content tended to be lower in comparison to feso 4 treated only (1.58 ϯ 0.24), but mda level didn't change (2.31 ϯ 0.72). in addition, treatment with spermine alone resulted in increase of mda level (2.74 ϯ 0.7 vs control p ͻ 0.01), iron content didn't change (0.59 ϯ 0.29), but carbonyl groups were decreased (0.99 ϯ 0.28 vs control p ͻ 0.05). feso 4 treatment increased gsh level (126.38 ϯ 34.11 nmol/mg prot. vs control 88 ϯ 22.77; p ͻ 0.05) while in combination with spermine this increase was more profound (235.48 ϯ 42.7; p ͻ 0.001 vs control, p ͻ 0.001 vs feso 4 ). spermine alone produced similar increase of gsh level (127.4 ϯ 34.11, p ͻ 0.05 vs control; p ͼ 0.05 vs feso 4 ). the results emanating from the human genome programme have required a reappraisal of protein science and have led to the rapid upsurge in interest in the area of proteomics. this sudden re-emergence of protein science, in fact, was predictable and should not have been surprising.recent experience of protecting group design with respect to lysine and aspartic acid will be discussed together with aspects of chemical synthesis of small proteins of biological significance and in the context of chemical synthesis methodology making contributions to the general field of proteomics. using a cell line permanently expressing the mouse taurine transporter (mtaut) as a fusion protein, we investigated the underlying mechanism by which the immunosuppressive drug cyclosporin a (csa) inhibits taurine transport. csa inhibited the recombinantly expressed mtaut function both in dose and time dependent manner. the inhibitory effect of csa was reversible. thus, washing out the csa resulted in almost complete recovery of taurine uptake. to obtain further insight, we examined the surface abundance of the mtaut as a function of csa treatment using a surface-labeling assay. our results demonstrated that csa treatment altered the surface expression of the mtaut without significantly altering its total expression level, and the reduction in the cell surface expression paralleled the decrease in taurine uptake. upon removal of csa, the virtual recovery in taurine uptake was due to the concomitant increase in the number of taurine transporters on the cell surface. taken together, our results suggest that csa induced inhibition of taurine uptake was either due to the impaired targeting of the taurine transporters to the cell surface or due to the removal of the transporters from the cell surface. polyamines are neuromodulators in a number of physiological and pathological conditions in cns. since application of ethylene glycols causes hypoactivity and lethargy of experimental animals, depression of cns and various neurological symptoms, the aim of this study was to examine the effects of 2butoxyetanol on polyamine and gaba catabolism, taking in account an alternative pathway of gaba synthesis from putrescine. methods: male wister rats were allocated into three groups: first treated by be (100 mg/kg -10 days), second key: cord-023208-w99gc5nx authors: nan title: poster presentation abstracts date: 2006-09-01 journal: j pept sci doi: 10.1002/psc.797 sha: doc_id: 23208 cord_uid: w99gc5nx nan background and aims: homodimerization of myd88 adapter protein is essential for nf-kb activation in the inflammatory pathway triggered by il-1 and tlr [1] . we designed a peptidomimetic of the myd88 tir domain consensus peptide arg-asp-val-leu-pro-gly-thr [2] , named st2825. here, we report its synthesis and biological activity. we also report the synthesis and biological activity of its enantiomer, st3511, and its diastereoisomers, st3489 and st3558. methods: the structure of the myd88 tir domain consensus peptide is subdivided into three distinct portions, the most important of which is a b-turn. in the peptidomimetic design we changed the b-turn with a tricyclic spirolactam [3] , already known [4] . we synthesized this building block, its enantiomer and two of 8 possible diastereoisomers by "in solution" synthesis. based on semiempirical calculation of heat of formation [5] , we could predict the right stereochemistry of the 4 products selectively obtained in the last cyclization step. results: these four compounds were tested for their biological activity by reporter gene assay (rga). some coimmunoprecipitation experiments were also carried out and we report their results. conclusions: the results show the activity of st2825 and its isomers on our target, with limited specificity towards their stereostructure. introduction of a methylene bridge between the cα(i+1) and the n(i+2) atoms in an open peptide (i) to mimic simultaneously the cαh(i+1) and hn(i+2) protons (β-lactam scaffold assisted design -β-lsad) has proven to be a practical tool for the preparation of monotopic β-turn peptidomimetics (ii, r2 = r3 = h), according to the principle of separation of constraint and recognition elements1. in this work we report a short, general, and stereocontrolled synthesis of multitopic β-lactam scaffolds of type vi. α-alkyl serinates iii are converted into the corresponding enantiopure nnosyl-aziridines iv which undergo "in situ" ring-opening with amino acids v. subsequent base-promoted cyclization affords the n-protected α-alkyl-α-amino-β-lactams vii. incorporation of the novel scaffolds into linear and cyclic peptides and their conformational features are also presented, most of them showing stabilized β-and γ-turn conformations. poly(amino acids) are emerging as promising therapeutic carriers finding widespread application in the field of drug delivery. in this context, polyproline polymers have been used to solubilize poorly water-soluble proteins, in affinity chromatography for the purification of platelet profilin, and more recently, in the design of dendrimers. poly(amino acids) are most conveniently synthesized by polymerization of the corresponding amino acid n-carboxyanhydride (nca). in spite of the interest of polyproline, the preparation of proline n-carboxyanhydride (pro-nca) renders poor synthetic yields. in this work a new method for the preparation of pro-nca in high yields and purities is described. amino acid n-carboxyanhydrides are obtained by the method described by fuchs. but, in the case of proline, the n-carbamoyl chloride does not cyclise spontaneously as it takes place with other amino acids, and the use of a non-nucleophilic base is required for the cyclisation. a tertiary amine, such as triethylamine, is commonly used but it renders a low conversion of the n-carbamoyl chloride to the expected pro-nca, together with the presence of the pro-pro diketopiperazine byproduct. in the present work, polymer-supported bases have been used instead of triethylamine. higher yields of pro-nca, and very low percentages of diketopiperazine have been obtained. in addition, no tertiary amine contamination was observed. polymer-supported bases could also be recycled and pro-nca yields were reproducible. in conclusion, we have developed an efficient method for pro-nca preparation with polymer-supported bases. the introduction of novel nonproteinaceous heterocyclic amino acids into peptides results in new compounds with interesting structural, physicochemical and biological properties. the transformation of amino acid side chains after the peptide assembly is a convenient method of generating such modified peptides. taking into account the biological activity and complexing abilities of nitrogen-containing heterocycles, we investigated the formation of imidazole, benzimidazole and quinoxaline moieties using condensation with various aldehydes and α-dicarbonyl compounds after classical peptide synthesis on solid support. the imidazole synthesis utilizes the n-terminal or side chain amino group of amino acids, whereas a derivative of phenylalanine, β-(4-amino-3-nitrophenyl)alanine, was developed for benzimidazole and quinoxaline synthesis. the modified peptides were purified by preparative hplc and characterized by esi-ms, uv and nmr. in conclusion, we developed a straightforward method of synthesis of peptides with specific ion affinity and spectral characteristic. the broad range of commercially available aromatic aldehydes and dicarbonyl compounds makes possible the synthesis of combinatorial libraries of modified amino acids and peptides. part of this work was supported by a grant no. 3t09a 110 28 from the ministry of education and science. nmda receptors belong to the ionotropic group of glutamate receptors. the activity of the receptor can be altered by compounds acting at binding sites. the (r,s)-(tetrazol-5-yl)glycine (tg) has been shown to be a highly potent nmda (n-methyl-d-aspartic acid) receptor agonist with exitotoxic effects [1] . the aim of our studies was to investigate the chelating ability of tg towards copper(ii) ions. copper is widely distributed throughout the body with a distinct concentration in the brain. copper enters cells as complex and seeks out targets requiring it to function. for these reasons it was interesting to evaluate stability and structure of tg -copper(ii) complexes. the equilibrium and structural properties of complex species were characterized by ph-metric and spectroscopic (uv-vis and epr) methods. in the system, polymeric species are dominant at acidic ph range having { nh2, coo-} coordination with possible ntetr bridging elements. monomeric complexes were found at physiological ph. the two tg molecules are bound to copper ion via four nitrogen donors. the formation of two {nh2, ntetr} donor sets results in very strong metal-ligand interactions and the complex species are very stable over a wide ph region. we have also performed an investigation on similar tetrazole compounds in order to compare the chelating ability of the tetrazole moiety . the targets of our studies were 1,5-diamino-1h-1,2,3,4-tetrazole [2] and tetrazole aspartic acid. references continuing work in that field, we synthesized oxytocins containing tetrazole analogues of amino acids. the 5-tetrazolyl group is widely used in medicinal chemistry as an isostere of the carboxyl group. compounds containing tetrazole ring appear to be metabolically more stable than their carboxylic analogues and have comparable acidity. we synthesized derivatives of aspartic, glutamic, and alpha-aminoadipic acids containing 1h-tetrazole ring in side chains. these derivatives were then used for syntheses of oxytocin analogues substituted in position 4. apart from above we also obtained two analogues with tetrazole analogue of glycine in position 9. the first one contains 1h-tetrazole ring, the second one has tetrazole ring substituted with methyl group in position 1. oxytocin analogues possessing amino acids with tetrazole ring in side chains were synthesized on amide resin using fmoc methodology. in the case of analogues with c-terminal tetrazole ring, fragments 1-7 were synthesized on resin and then coupled with suitable dipeptides in solution. all obtained peptides show no pressor and rather low uteronic activity. however, for some analogues the uterotonic activity when measured in the presence of magnesium ions was several times higher. in humans, two classes of defensins, α-defensin and β-defensin, have been identified on the basis of tissue specificities and structural features including their modes of disulfide pairing. in general, particular combinations with disulfide bonding in cysteine-containing peptides are critical for expressing their intrinsic biological activities. in the case of human α-and β-defensins, however, disulfide isomers without the native pairing were demonstrated to exhibit similar antimicrobial activity to that of the native defensins. therefore, to assess the biological activities of defensins as well as defensin-based therapeutics, extreme care is required in the chemical synthesis of these peptides to avoid ambiguity in quality. in the present study, we synthesized human α-defensin-1, -2 and -4, and human β-defensin-1, -2, -3 and -4 by employing boc chemistry, and determined the optimal conditions for folding the respective reduced peptides preferentially into a native conformation. among the factors affecting the oxidative folding in the presence of reduced and oxidized glutathione, the buffer concentration and reaction temperature were essential. all the synthetic human α-and β-defensins were confirmed to have the respective native disulfide pairing by sequential analyses and mass measurements with cystine segments obtained by enzymatic digestion. all the human α-and β-defensins could be efficiently oxidized to the α-and β-defensin-type disulfide structure, respectively, under several conditions determined in the present study. these synthetic peptides of high homogeneity were used to accurately assess the antimicrobial activity. native chemical ligation is based on the reaction of a peptide bearing a c-terminal thioester group with an n-terminal cysteinyl peptide, leading to the formation of an amide bond at the aa-cys junction. the key starting materials for native chemical ligation are unprotected c-terminal thioester peptides. thioester peptides are often prepared using boc/benzyl solidphase peptide chemistry. however, the widespread use of the fmoc/tert-butyl chemistry for peptide synthesis, over the boc/benzyl method, has stimulated the development of methods allowing the preparation of thioester peptides that are compatible with the basic treatments used to remove the fmoc alpha-amino protecting group. we report here a novel method for thioester peptide synthesis that is based on the use of the sulfonamide safety-catch linker. once the peptidyl chain is assembled by fmoc/tert-butyl chemistry, the thioester function is generated on the solid-phase through an intramolecular n,s-acyl shift. the procedure seems to be insensitive to the bulkiness of the amino acid directly attached to the sulfonamide linker. the thioesters were successfully used for native chemical ligations in solution or on the solid support. we optimized the recognition sequence of the substrate and the reaction conditions with respect to the yield. the sortase-mediated ligation was successfully applied to the synthesis of cellpenetrating peptide-pna conjugates which showed enhanced activity in antisense experiments compared to pna alone. this ligation strategy was also employed for the coupling of a chemically synthesized construct of the extracellular loops of the crf-receptor with the corresponding n-terminal receptor domain, which was expressed in e. coli. this 23 kda protein behaves like an artificial receptor, binding specifically natural ligands. linear gramicidins represent the most investigated family of antibiotic peptides forming ionic channels. gramicidins produced by bacillus brevis are hydrophobic peptides composed of 15 amino-acids with d and l configuration strictly alternate. the presence of d-amino acids in the sequence of gramicidin a (hco-val-gly-ala-dleu-ala-dval-val-dval-trp-dleu-trp-dleu-trp-dleu-trp-nhch2ch2oh) should possible make the peptide highly resistant to proteolysis [1] . striking features like ethanolamine group in c-terminus, the n-terminal n-formylated valine and the high hydrophobicity of the peptide sequence, make the solid-phase synthesis of gramicidin a very tricky. therefore, we followed a new synthetic strategy for peptide chain elongation assisted by microwave energy. in fact, microwave energy has been demonstrated to produce highpurity compounds with more rapid reaction times, enhancing coupling rates and efficiency in difficult syntheses [2] . however, microwave-assisted solid phase peptide synthesis (mw-spps) has not been yet extensively investigated. in this context, we synthesized gramicidin a by mw-spps in high yield and purity, enhancing reaction rate compared to the traditional spps. thermal disruption of peptide aggregation, induced by microwaves, is possible favorable for obtaining this particularly difficult sequence. gramicidin a was incorporated in synthetic lipid bilayers, self-assembled on mercury electrodes, characterized by hydrophilic spacers interposed between the metal and the lipid bilayer. we tested the behaviour of gramicidin a in biomimetic membranes using electrochemical impedance spectroscopy (eis), ac voltammetry and other electrochemical techniques [3] . [ csf114(glc) is an n-glucosylated peptide to be produced in large scale by peptlab because it is the active molecule of the first specific diagnostic/prognostic test for monitoring disease activity and guiding therapeutic treatments of multiple sclerosis patients [1] . in order to develop a synthetic protocol by an automated instrumentation, increasing yield, purity of the crude, and reaction time, a microwave-assisted solid phase peptide synthesis was validated comparing the use of the new generation of triazine-based coupling reagents (tbcrs) with a series of commonly used ones. activation of carboxylic acids by tbcrs is particularly effective because of formation of triazine "superactive esters". the usefulness of tbcrs as coupling reagents has been recently confirmed in the synthesis of z-, boc-, and fmoc-protected dipeptides, sterically hindered amino acids, in the synthesis of esters, in manual and automated spps of difficult peptide sequences, and head-to-tail constrained cyclopeptide analogues [2] . moreover, we also demonstrated tbcrs efficient in a microwave-assisted solution synthesis of the n-glucosylated building block fmoc-asn(glcoac4)-oh using a manual monomode microwave instrument [3] . this building block was used to obtain csf114(glc) comparing the efficacy of a monomode microwave automatic instrument with the traditional solid-phase peptide synthesizers such as the manual and automatic in batch systems, as well as the continuous-flow one. it is known that enzymatic peptide synthesis is more advantageous than chemical synthesis in many aspects; it is highly stereoselective, racemization-free and requires minimal side-chain protection. the method is, however, limited to the use of amino acid derivatives which meet the enzymatic specificity as a coupling component. this problem may be solved using enzymes which have wide specificity of substrate. but in this case, secondary hydrolysis of the resulting peptide may arise from the inherent nature of the protease. in this matter, ficin and ficin-like enzymes were used as cysteine protease to analyze the diminishment of specificity for the substrate. the cysteine protease-catalyzed peptide coupling reaction has been studied by using synthetic fourteen boc-amino acid phenyl and naphthyl esters as acyl donor. the reaction conditions were optimized for organic solvent, ph, and concentration of acceptor. the coupling reaction was carried out by incubating an acyl donor (1 mm) with an acyl acceptor (ala p-nitroanilide, 35 mm) and enzyme (0.1u) in a mixture of gta buffer (50 mm, ph 9.0) and dmso (3:2) at 37ْc. the progress of the coupling reaction was monitored by rp-hplc. the products were obtained in satisfactory yields. non-enzymatic glycosylation, also called glycation, is a common modification in living organisms formed by the reaction of carbohydrates with free amino groups of peptides and proteins. it is a slow chemical reaction yielding amadori products undergoing further oxidation and degradation reactions finally leading to advanced glycation end-products (age). amadori products are early markers for ageing, diabetes mellitus and alzheimer's disease. despite the clinical importance of these amadori products, universal protocols to synthesize amadori modified peptides are still missing. here we describe a solid phase strategy for the glycation of specific amino groups on partially protected resin bound peptides using a global post synthetic approach. the peptides were synthesized by standard fmoc/tbu-chemistry using carbodiimide activation. the lysine position to be modified was incorporated with a methyltrityl protected ε-amino group, which can be selectively cleaved after completion of the peptide synthesis with 1% tfa in dichloromethane. the partly deprotected peptide was glycated in methanol using a ten-fold molar excess of 2,3-4,5-di-o-isopropylidene-aldehydo-β-d-arabino-hexos-2-ulo-2,6-pyranose and nabh3cn for 18 h at 70°c. after cleavage the overall yields were in the range of 50 -70 % for the tested octapeptides. all byproducts were well separated by rp-hplc allowing a simple purification strategy even for medium-sized peptides. thus the general strategy presented here allows routine synthesis of amadori peptides at reasonable yields and purities using standard protocols established in most laboratories synthesizing peptides. 2-chlorotrityl chloride resins are recommended for the synthesis of c-terminal proline peptide acids to overcome diketopiperazine formation during chain assembly. however, we have found these (and similar) resins to be unsuitable for the synthesis of peptides greater than 20 residues. for example, the chemokine guinea pig eotaxin, (73 residues c-terminal proline) assembles poorly if not at all on a 2-chlorotrityl resin. we sought to circumvent these problems in the chemical synthesis of peptides and proteins, through the development of a resin-swap procedure. whereby the initial c-terminal protected tripeptide is assembled on a 2-chlorotrityl resin, liberated from the solid-support, then reattached to a resin that is suited for long chain peptide / protein synthesis. using this approach, the synthesis of guinea pig eotaxin is reported. the tripeptide fmoc-thr(but)-lys(boc)-pro-oh was assemble on 2-chlorotrityl resin, cleaved with 20% tfe in dcm and attached to wang resin using standard protocols. peptide assembly gave the gp eotaxin in 53% overall yield (as determined by uv monitoring). fmoc-on cleavage, purification and tag removal followed by folding gave the native chemokine in good yield. choice of resin is one of the most critical factors in ensuring a successful peptide synthesis, we have shown the superiority of wang resin over chlorotrityl resin in the synthesis of medium and long peptides and developed a method for the synthesis of c-terminal proline containing peptides which overcomes the problem of diketopiperazine formation. the technique is being applied to the synthesis of other c-terminal proline peptides e.g. human eotaxin and ip10. dimerization of cell receptors, involved in antigen presentation, is an essential step in several cellular signal transduction processes, therefore substances that are able to modulate such a process are of potential therapeutic value. dimeric peptide ligands could represent useful tools to cause dimerization of such receptors. a similar strategy applies dimerization of ligands, interacting with dimeric proteins or proteins with multiple binding sites, to design molecules with enhanced affinity. dimeric analogs of the immunosuppressory hla class ii fragments were synthesized using suitably modified, standard fmoc solid-phase protocols and mbha-resin. the dimerization was achieved by crosslinking n-terminal amino groups of the peptides with the commercially available mixture of poly(ethyleneglycol)biscarboxylic acid (average mw 600, length range 30-45å), activated by esterification with pentafluorophenol. the same procedure was applied to synthesize a series of dimeric analogs of c-terminal fragments of plexin-b, consisting of two undecapeptides, linked by the polyethyleneglycol spacers. other biand polyvalent linkers were also investigated. our results demonstrated that the amino-terminal dimerizations of the tested hla-fragments resulted in enhanced immunosuppressive activities, whereas interaction of pdz dimer with the plexin fragments led to about 20-fold increase in affinity, as compared to their monomeric counterparts. [background and aims] elucidation of alzheimer's disease (ad)-related aß1-42 dynamic events is a difficult issue due to uncontrolled polymerization. [methods] based on the "o-acyl isopeptide method" (chem. commun. 2004, 124; j. am. chem. soc. 2006, 128, 696), we have developed a novel photo-triggered "click peptide" of aß1-42 (1), e.g., "26-n-nvoc-26-aiaß42 (2)", in which a 6-nitroveratryloxycarbonyl (nvoc) group was introduced at ser26 in 26-o-acyl isoaß1-42 (26-aiaß42, 3). [results] i) the click peptide 2 did not exhibit the self-assembling nature under physiological conditions due to one single modified ester; ii) photo-irradiation of the click peptide 2 and subsequent o-n intramolecular acyl migration afforded the intact aß1-42 (1) with a quick and one-way conversion (so-called "click"); and iii) no additional fibril inhibitory auxiliaries were released during conversion to aß1-42 (1). [conclusions] this method provides a novel system useful for investigating the dynamic biological functions of aß1-42, such as the self-assembly and aggregation processes in ad. several insulin analogues have recently been introduced clinically for improved treatment of diabetes. industrial productions of such insulins are based on microbial expression systems, which are highly efficient, but generally limited to the 20 proteogenic amino acids. also, some sequences form inclusion bodies or fail to express. the total chemical synthesis of insulin in research scale was a landmark achievement in peptide science. however, the most commonly used method relies on recombination of a-and b-chains under "random" folding and pairing of the three disulfide bridges. this folding/oxidation step is difficult and low yielding. a general approach using a removable auxiliary which can direct correct formation of disulfide bridges is highly desirable. in the pancreas as well as in microbial expression systems, insulins are prepared and folded as single chain precursors, with a c-peptide connecting the a and bchains. the c-peptide helps direct the orientation of a and b-chains in obtaining the correct disulfide pairing and overall peptide folding. upon folding, the c-peptide is removed enzymatically. we report here a new method for total chemical synthesis of insulin by use of fmoc-based step-wise solid-phase synthesis of single-chain precursors followed by cpeptide directed folding and cleavage of c-peptide, thereby allowing total chemical synthesis of novel insulins with unnatural substitutions. 2-chloro-4-methoxy-1,3,5-triazines 1a-c anchored on cellulose, silica or wang resin were prepared by the treatment of 2,4-dichloro-6-methoxy-1,3,5-triazine with appropriate solid support in the presence of a base. immobilized, environmentally friendly triazine coupling reagents 3a-c were obtained by treatment of 1a-c with n-methylmorpholinium p-toluenesulfonates 2 in the presence of hcl acceptor. the loading of the solid carriers were calculated from n, s contents, determined by microanalysis. all prepared immobilized n-triazynylammonium toluenosulfonates 3a-c have been found stable at room temperatures. activation of carboxylic components afforded triazine activate esters 4a-c connected to the support. treatment of 4a-c with appropriate amino components gave amides or peptides. the final products, chromatographically homogenous amides and peptides, were isolated by filtration or extraction from the solid support. mutter's pseudoproline dipeptides and sheppard's hmb derivatives are powerful tools for enhancing synthetic efficiency in fmoc spps. they work by exploiting the natural propensity of n-alkyl amino acids to disrupt the formation of the secondary structures during peptide assembly. their use results in better and more predictable acylation and deprotection kinetics, enhanced reaction rates, and improved yields of crude products. however, these approaches have certain limitations: pseudoproline dipeptides can only be used for sequences containing serine or threonine, and the coupling of the amino acid following the hmb residue can be extremely difficult. to alleviate some of these shortcomings, we have prepared fmoc-ala-(dmb)gly-oh and fmoc-gly-(dmb)gly-oh. these dmb-dipeptides can be incorporated into peptides in place of ala-gly and gly-gly, resulting in peptides containing structure breaking (dmb)gly residues. by introducing the (dmb)gly residue as part of a dipeptide unit, the need to acylate the highly hindered secondary amino group of (dmb)gly is avoided. on treatment with tfa the dmb group is cleaved regenerating gly. to test the efficacy of our new derivatives in expediting the synthesis of hydrophobic peptides, we undertook the preparation of the challenging neurotoxic prion peptide 106-126 1; this peptide reportedly can not be made using fmoc spps methods. the dipeptides marked in bold were systematically substituted with the appropriate dmb peptides. the effects of the substitution were evaluated using conductivity monitoring and lc-ms analysis of the crude peptides. h-lys-thr-asn-met-lys-his-met-ala-gly-ala-ala-ala-ala-gly-ala-val-val-gly-gly-leu-gly-oh 1 th120 efficient dipeptide production form unprotected l-amino acids with the novel enzyme l-amino acid α-ligase. k. tabata 2 , h. ikeda 1 , m. yagasaki 1 , s. hashimoto 1 background and aims: application of α-dipeptides has been limited due to the lack of cost-effective manufacturing methods. the known methods require the protection of amino acid(s) to fix the order of the amino acids ( fig. 1) . furthermore, they usually accompany the formation of longer peptides. to establish the costeffective manufacturing method, a novel activity which synthesizes α-dipeptides from two unprotected l-amino acids was screened. methods and results: a gene was found in the genome of bacillus subtilis by in silico screening based on a putative reaction mechanism. the purified protein coded on the gene, i) catalyses α-dipeptide formation from unmodified l-amino acids with a specific order in an atp-dependent manner, ii) never forms tri-or longer peptides, and iii) takes a wide variety of l-amino acids but no d-amino acids. the enzyme was tentatively named l-amino acid α-ligase (lal). the whole cell reaction of a recombinant e. coli strain expressing lal and polyphosphate kinase (ppk) with two l-amino acids and polyphosphate (polyp) enable the efficient production of many dipeptides with a certain order of the constituent amino acids through the coupling reaction of lal and ppk (fig. 2) . conclusion: a novel enzyme, lal, enables to synthesize dipeptides cost-effectively directly from unmodified l-amino acids. t. ye 1 marine organisms continue to provide rich sources of structurally unique and pharmaceutically active compounds. due to the difficulties in the isolation of significant quantities of these natural products, synthetic chemistry serves an important role in their structural assignment and biological evaluation. antifungal agents have received considerable attention recently since the spread of hiv has left many people open to fungal infections, and there is a rapidly growing number of drug resistant strains of fungus emerging. ll-15g256gamma is a cyclodepsipeptide isolated from the marine fungus hypoxylon oceanicum and structurally assigned in 1998 by schlingmann. the structure of ll-15g256gamma was determined by a combination of chemical degradation, chiral chromatography and spectroscopic analysis. ll-15g256gamma uniquely combines a beta-ketotryptophan and a polyketide portion within a macrolactone ring. ll-15g256gamma has exhibited potent activity against fungal strains and as such, is an attractive compound to develop as a future therapeutic agent. to date, there have been no reported studies towards the synthesis of ll-15g256gamma. we have completed the total synthesis of ll-15g256gamma by employing the macrolactamization followed by a c-h oxidation as the key step. aspartimide (aminosuccinimide, asu) formation is the first step in the degradation of asp/asn containing peptides and proteins. the reaction is especially prevalent at asx-gly sites and results in a variety of rearranged and racemized products. the bases used in fmoc-tert-based spps promote the formation of asu and related products. we recently found that the dmb backbone protection efficiently prevents secondary structure formation at gg sites and is orthogonal with respect to standard fmoc spps. here we explore the use of dmb, tmb and nbzl groups (z) for the synthesis of "difficult"/asu-prone peptides, in three different schemes: a) fmoc-asx-(z)gly-oh dipeptide building blocks; b) fmoc-(z)gly-oh monomer building blocks, and c) two steps "submonomeric" approach for synthesis of substituted n-benzyl glycines on the resin. we tested the new methods on two model peptides vkd/ngyi and ha21-20hiv-tat48-57 (h-g1lfgaiagfi engwegmidg20grkkrrqrrr30-oh) fusion peptide. the yield and purity of the products reach and even exceed the level in control experiments obtained with hmb protection and the peptides were found free of asu/piperidides. the acid removal of the dmb protection is ~30% faster than that of hmb. the submonomeric route (strategy c) is especially simple, efficient, cost effective and it allows the use of different amines for halogen-displacement. the backbone protecting groups used were in many respects superior to the commercial reagents and applicable for synthesis of both peptide acids and peptide amides. the use of nbzl-nh2 for halogen displacement represents a new method for preparation of backbone-caged peptides. alkyl bonded silica gels historically have been the standard in reversed phase (rp) purification of biomolecules such as synthetic peptides, small proteins, and oligonucleotides. silica gels provided the resolving power needed for challenging separations and the mechanical stability required to be operated industrially under high pressure conditions. the chief disadvantage of silica gels is poor chemical stability under alkaline conditions, which limits their capability to withstand rigorous clean and sanitization -in-place (cip/sip) protocols. as a result, polymeric media have gained recent market attention because of their excellent chemical stability, which enables full compatibility with modern cip/sip protocols. however, first generation polymeric gels lacked both the resolving power and the mechanical stability to be compatible with industrial high pressure dynamic axial compression (dac) hardware. rohm and haas' advanced biosciences division recently introduced a new, monospheric, 10 micron, high performance polymeric rp material. unlike existing softer polymeric gels, this product has higher mechanical stability which enables it to be used effectively with industrial dac / hplc hardware. in addition, this material provides high resolving power for the most challenging industrial separations, because of its unique and selective pore structure, as well as its small monospheric particle size. finally, because of its excellent chemical stability, the media is not limited in the range of ph that can be used. the combination of mechanical stability for high throughput, chemical stability for long lifetime in use, and high resolution for high yield, together translate to an effective cost-in-use solution for industrial polishing processes. we have developed new types of peptide nucleic acids with improved water solubility by introducing ether linkages and pyrrolidine rings in the main chain; pyrrolidine-based oxy-pnas (popnas). in this work, cellular uptake and endosomal release of the trans-l-popna oligomers, one of stereoisomes of the popna, were investigated. the cellular uptake was achieved by combining the popna oligomer with an n-terminal 23-mer peptide of an influenza virus hemagglutinin protein (ha2) that is labeled with a rhodamine fluorophore at the n-terminal and covalently linked with a hepta-arginine unit at the c-terminal (rho-ha2-r7). the fluorescence images of the cho cells after incubation with fam-po(13) [fam-o-cag tta ggg tta g-gly-nh2] in the absence and presence of rho-ha2-r7 were observed with confocal laser-scanning microscopy. incubation with fam-po(13) alone, no internalization of the oligomer was observed. in the presence of rho-ha2-r7, however, fam-po(13) was successfully internalized into cho cells and, more importantly, the fluorescence spread over the whole cell. the fluorescence image indicates that the popna oligomer in combination with the ha2-r7 peptide was transferred into cytoplasm within 1 h. since both the red (rho) and green (fam) fluorescence spread over the cytoplasm, the popna oligomers that were taken up into endosomes together with the rho-ha2-r7 were released into cytoplasm as the disruption of the endosomes by the ha2 peptide. in summary, the popna oligomers were readily taken up into cytoplasm of cho cells, when combined with a ha2-r7 peptide. most of functional rnas have post-transcriptional modifications, some of which are quite important for their structure and function. thus, for studying such rnas, it is necessary to use purified raw rnas obtained from living organisms. isolation of native rna is necessary also in the case of analyzing the sequence and modifications of mature rna, which may be different from simple transcript of its gene. therefore, rna isolation method is required. many previous reports demonstrated isolation of rnas, especially trnas. most common and traditional purification methods are based on successive column chromatographies. it seems difficult to apply such method to every trna because effective combination of columns varies among individual trnas. to overcome the difficulty, a sequence-specific selection method using a solid-phase dna has been devised. in this method, a trna can be purified from rna mixture by a single step. however, this method needs high temperature treatment, which might assist hydrolysis of rna strand and might impair heat labile modifications. pna-rna hybrid has been known to be much more stable than dna-rna hybrid. thus pna-based rna purification method seems to be possible for wider variety of rnas in lower temperature, in comparison with dna-based method. in this study, we attempted to purify a single rna, such as a trna and a noncoding rna, from rna mixture by using immobilized pna. r. pipkorn 1 , w. waldeck 2 , h. spring 3 , j. jenne 4 , k. braun 5 background and aims: safe drug delivery technologies are pivotal for genetic interventions, but viral vectors baer the risk of inflammatory reaction. questions concerning the efficacy of delivery of the genetic substances, the desired topical gene activation and targeting must be answered. therefore we attempted to develop a membrane non-perturbing delivery system for transport of inactive functional genes into cells and tissues. genes can be subsequently activated at the target site. our concept bases on the use of peptide-nucleic-acids (pnas) resistant against proteases and nucleases, oligonucleotide derivatives, in which the phosphate-backbone has been replaced with ethylen-amin connected alpha-amino-ethylglycine-units. methods: peptides conjugates were composed and synthesized according to the solid phase synthesis and protecting group chemistry strategies. pna sequences were conjugated covalently, non cleavable, with a capronic acid spacer to the nls, pkkkrkv. pnas have gained broad attention in antisense/antigene experiments and as diagnostic tools. in principal, they can be synthesised with several activating reagents known from peptide synthesis. namely, hatu or pybop are often used. synthesis with hatu is more laborious, because preactivation is needed in order to avoid guadinylation of the n-terminus of the growing pna-chain. we wanted to use pybop, because preactivation should not be needed in this case, which is especially useful in automated synthesis. surprisingly, in the pybop-mediated syntheses of 18mer pnas we obtained products showing molecular masses approx. 67 da above the expected ones. detailed analysis revealed, that the modification occurred at the only guanine residue in the sequence. in order to further characterise the side reaction, a short pna fragment was synthesised using hatu and pybop activation, respectively, and cleaved from the resin with and without the n-terminal fmoc-group. while synthesis with hatu gave the desired products, pybop partly activates the aromatic carboxy group of the guanine residue, which is substituted by piperidine during subsequent fmoc cleavage. the modified sequences could be further characterised by ms/ms-fragmentation. our results show that care must be taken when synthesising pnas with pybop activation. on the other hand, this reaction possibly opens an opportunity to synthesise guanine derivatives. the opioid receptor system in the central nervous system (cns) controls a number of physiological processes including pain, reward, gastrointestinal and cardiovascular functions. as a consequence, most pain modulating compounds currently available cause a variety of side-effects. the endogenous ligands for the opioid receptors are a series of peptides that includes endomorphin-1. endomorphin-1 has been shown to elicit potent anti-nociception through the highly selective activation of µ-opioid receptors. it is this receptor that mediates supraspinal analgesia and thus, selectivity for this receptor results in analgesia without affecting other processes. therefore, endomorphin-1 is considered a promising lead compound for the development of a new, safer pain medication. we have synthesized a large number of lipid-and carbohydrate-modified endomorphin-1 analogues and screened these compounds for their binding and activation of µ-and δ-opioid receptors in sh-sy5y cells as well as caco-2 cell monolayer permeability and plasma stability. compounds conjugated with either a lipoamino acid or sugar moiety on the c-terminus lost binding affinity by several orders of magnitude, whilst n-terminal conjugations resulted in minimal loss of binding affinity. a number of analogues showed pm binding affinity and high apparent permeability, and of these compounds, one has been selected for assessment in nociceptive and neuropathic pain models. in addition to these pre-clinical studies, internalization and tolerance formation of these compounds has also been measured in an effort to synthesise a non-tolerant opioid agonist. endomorphin-1 analogues with a high degree of amphiphilicity cause increased receptor internalization and subsequently less tolerance formation. a. marcinkowska 1 , l. borovičkova 2 , j. slaninowá 2 , z. grzonka 1 carbohydrate moieties of glycopeptides and glycoproteins play different decisive roles in various biological phenomena. conformation and solubility of proteins are influenced by the oligosaccharide chains, which can also inhibit the proteolytic degradation. as a result, the synthesis of glycopeptides is an attractive field that contributes to understanding of mutual interactions between both moieties and for their biological interest. the synthesis of glycopeptides requires a combination of synthetic methods from both carbohydrate and peptide chemistry. moreover, this synthesis needs stereoselective formation of the glycosyl bond between a carbohydrate and a peptide (amino acid) part, and also an appropriate protecting group methodology that allows selective deblocking of only one functional group in these polyfunctional molecules. in the present work we modified the oxytocin and vasopressin structure with glycoamino acids. transformations of fmoc-protected serine and threonine derivatives into appropriate o-glycosylated precursors suitable for solid phase peptide synthesis were worked out. the -and -o-glycosides were synthesized from fmocserine and fmoc-threonine allyl esters and appropriate glycosyl bromide using hanessian's modification of the koenigs -knorr reaction. these n--fmoc-protected glycosides were used in synthesis of glycopeptides. eight analogues of oxytocin modified in position 4 were obtained. we have also prepared two types of lysin-vasopressin analogues modified with glycoamino acid, in which the glucuronic acid was attached to the ω-amino group of lysine in position 8 through the amide bond. glycosylated analogues of oxytocin and vasopressin display an increased stability towards enzymatic degradation, and retain some hormonal activities. supported by grants: ds/8350-5-0131-6 (zg) and z40550506 (js) according to many authors the formation of amadori products is a key stage in the glycation process. glycated proteins may show allergenic properties and potentially initiate autoimmunological processes. they may also serve as the markers of diabetes. to our best knowledge, all procedures concerning the synthesis of peptide-derived amadori products reported in literature are based on "in solution" approach which makes them tedious and time consuming. a modified method of the solid phase synthesis of peptide-derived amadori products based on direct alkylation of the deprotected ε-amino groups with 2,3:4,5-di-oisopropylidene-β-d-arabino-hexos-2-ulo-2,6-pyranose in the presence of sodium cyanoborohydride was proposed. isopropylidene groups, protecting the sugar moiety in the obtained conjugate, were removed with trifluoroacetic acid containing 5% water. studies on optimization of the reaction performed on the model peptide attached to a wang resin, fmoc-lys-leu-leu-phe-(resin), showed that the best yield of the product is attained with a two-fold excess of 2,3:4,5-di-oisopropylidene-β-d-arabino-hexos-2-ulo-2,6-pyranose and a five-fold excess of sodium cyanoborohydride. the identity of the product was confirmed by high resolution ms. the several side products were isolated and their structures will be discussed. our results prove that the synthesis of glycated peptides in the solid phase is feasible. the lack of homogeneous glycoproteins in sufficient quantities is an ongoing challenge in glycobiology. in order to solve this problem researchers have turned to a variety of approaches ranging from mutant eukaryotic strains to the highly demanding total synthesis of glycoproteins. [1] using rnase b as a model nglycoprotein [2] we have searched a path to assemble this enzyme employing a combination of chemical and recombinant methods. native chemical ligation [3] allows the coupling of protein segments of unrestricted size in a chemoselective manner. we have developed solid phase methods to produce the required thioester building blocks 1-25-sr (a) and glycopeptide thioester 26-39-sr (b) containing an n-glycan at asn34 on a dual linker pega resin. [4] the remaining segment 40-124 (c) was expressed in e. coli as a fusion protein and released by intein mediated protein cleavage. [5] sequential coupling of the three rnase segments requires the use of a protective group at the n-terminus of segment b compatible with the oligosaccharide part. dysfunctional mutations of antitrypsin can result in a loss of elastase inhibitory activity or allow self-aggregation to occur and cause emphysema and cirrhosis, respectively. insights of the mechanism of disease provide strategy to cope with the aberrant protein aggregation and may bring potential therapeutic agents. in the present work, we describe our effort to identify effective anti-protein polymerization ligands by the employment of combinatorial technology. antitrypsin from human plasma was purified by glutathione sepharose and mono q-sepharose column chromatography. both ala-scanning and peptide shortening were carried out systematically to explore the structural requirements necessary for binding. combinatorial chemistry was then employed to conduct the library screening experiments. assessment of peptide binding was achieved through an unique gel electrophoresis assay. the structural requirements and the minimal peptide length required for binding were revealed by our systematic approach. this information was critical for the design of combinatorial library and the discovery of antitrypsin binding peptides with much improved affinity and specificity. there is currently no effective cure for z antitrypsin related cirrhosis and emphysema. the synthesis and screening of combinatorial libraries offer avenues to increase throughput and ultimately lead to the discovery of inhibitory peptides to the polymerization of pathogenic antitrypsin. with the rapidly increasing number of biopharmaceuticals in the industrial pipeline the need for efficient and expedient purification procedures is growing ever greater. affinity chromatography is one of the most promising technologies in this regard, as it offers very high selectivity and can often replace lengthy and expensive traditional chromatographic procedures. the use of combinatorial split-and-mix libraries is a powerful tool for discovering new affinity ligands but the technique has been limited by the laborious spectroscopic and chemical analysis needed to identify the binding ligand. we have previously introduced a novel bead encoding technology based on a 3-dimensional image recognition of patterns made by fluorescent particles randomly distributed inside larger beads. [1] the beads are read prior to each chemical transformation by an instrument featuring three fluorescence microscopes at a rate of 5,000 beads per hour. we here present the development of small peptidomimetic affinity ligands for the human growth hormone (hgh) by the use of this technology. the library was sought enriched prior to synthesis by in silico screening of a virtual combinatorial library using a large number of diverse building blocks. binding ligands were identified by incubation with fluorescence tagged hgh. [ the cinnamic acids and their derivatives have been found to possess a variety of biological effects, including antiviral, antimicrobial, antitumor and antioxidant activity. for example, several hydroxycinnamic acid conjugates with amino acids, isolated from plant sources showed enhanced antioxidant activity. the synthesis of cinnamic acid amides and their opioid activity was also cited in the literature. however the synthesis and pharmacological properties of sinapoyl-peptide amides continues to be virtually unexplored. on the other hand, the synthesis and opioid activity of analogs of tyr-mif-1 has been well documented by us. herein we present a synthesis of a series of sinapoyl -peptide amides where sinapic acid were attached consecutively to both c-and n-end of the tyr-mif-1 peptide chain: sa-pro-xaa-gly-nh2; sa-tyr-pro-xaa-gly-nh2; pro-leu-gly-nh(ch2)nnh-sa sa=sinapic acid; xaa=leu, unusual aminoacid; n=2,3 to obtain the sinapoyl-peptide-amides, both fmoc-and boc-based spps approach were used. analgesic activity was determined by the randall-sellitto paw-pressure test. the antioxidant effects were examined by dpph test as well. studies to establish the importance of introducing the sinapoyl moiety in the tyr-mif-1 molecule for the antioxidant and opioid activities are underway. several proteins are involved in the transcription of dna to mrna, among which the basic leucine zipper (bzip) proteins. these transcription factors bind specific dna sequences by dimerization and inserting short alpha-helices into the dna major groove. because the dimerization domain is only required to obtain the correct geometrical positioning of the alpha-helices, we will replace it by a dipodal steroid scaffold with defined stereochemistry. due to orthogonal protecting groups, a unique feature of this scaffold is the possibility to design not only homodimers, but also heterodimers. therefore this strategy allows for the construction of both major/major groove and major/minor groove binding peptides, either mimicking naturally occurring proteins or designing peptides with new binding properties. native chemical ligation and staudinger ligation are both suitable for the construction of these peptide dimers. moreover, a combination of solution-and solid-phase chemistry allows for the generation of combinatorial libraries. the increasing number of antibiotic-resistant bacteria is a global health problem. therefore the development of new highly efficient drugs is one of the major tasks of this century. as an example of peptides, which inhibit the growth of e. coli, we demonstrate an easy and rapid method for finding peptides with optimized antimicrobial properties. as a first step we built a modular construct. this construct consists of a constant cationic and a variable module. the cationic module was choosen to achieve cellpenetrating properties. the variable module was expected to act as the virtual active part of the peptide. to increase the proteolytic stability of the peptide we synthesized them in cyclic form. in the first step we used the combinatorial approach to screen approximately 64.000.000 peptide sequences in the variable region in order to find highly active peptides against e. coli. to optimize the identified sequence, we substituted all amino acids of the sequence with other amino acids and building blocks. additionally, in order to increase stability we modified the bridging. in this way we were able to uncover peptides with high antimicrobial activity as well as proteolytic stability and reasonable solubility. a series of melanocortin active core tetrapeptide hfrw nonpeptide imitations has been prepared using a combination of solution and solid phase synthesis. most of them included residue of 3-(1-imidazolyl) propylamine or histamine as substitutes of histidine. phenylalanine residue, which is included in melanocortins was replaced by residues of derivatives of 4, 4'-disubstituted isopropylidenedicyclohexane, 4, 4'-disubstituted bicyclohexane, 1,4-disubstituted cyclohexane, 1,5-disubstituted cyclooctane, and 1,2-, 1,3-or 1,4disubstituted benzenes. instead of arginine, residues of oligomethylene diamines, 2-butyl-2-ethyl-1,5-pentanediamine, 4,4'-methylene-bis(cyclohexylamine), and 4,4'-diaminodiphenylmethane were introduced. 2-naphtyloxyacetyl-, (4-1h-indol-3-yl)-butyryl-, 2-phenyl-ethanesulfonyl-and naphthalene-2-sulfonyl-groups served as replacement of tryptophan residue. tested on binding assay on melanocortin receptors, active core imitations exhibited a micromolar affinity to them. isopropylidenedicyclohexane and bicyclohexane derivatives showed about 10 fold higher affinity compared with corresponding derivatives of cyclohexane, cyclooctane or disubstituted benzene. obestatin is a novel endogenous ghrelin-associate peptide, which is involved in the regulation of food intake and weight gain. it was shown to be anorexigenic, able to decrease food intake, gastric emptying and jejunal motility. although obestatin and ghrelin originate from a common prepropeptide of 117 residues, they are reported to exert opposing physiological roles, by binding distinct receptors belonging to the subgroup of type a gpcrs [1] . obestatin was found to be the natural ligand of the orphan gpr39 receptor, a gpcr, expressed in jejunum, duodenum, stomach, pituitary, ileum, liver and hypothalamus. as many other peptides involved in the obesity process, it is a new and interesting drug target for the discovery of new anti-obesity molecules. in particular, the first step for the design of new molecules with potential improved anti-obesity activity, is the elucidation of the obestatin conformational features. here, we present the synthesis and the conformational analysis by nmr and cd spectroscopies of obestatin and its related 13-mer c-terminal sub-fragment, in aqueous solution and in membrane mimicking environment. the data outline the obestatin c-terminal portion as the region characterized by significant conformational features potentially opened to interesting future developments. [ a total of 50 isolates of rhizobium were collected from root nodules of medicago sativa and melilotus officialis plants in different regions of isfahan province .all of isolates on ty medium formed white ,slimy colonies with smooth margins and their inoculation on to roots of young alfalfa plants produced spindly nodules . the nodules developed with some of the isolates were big and pinkish ,although the rest of isolates produced small and white nodules .the speed of nodulation for all the isolates was almost similar and the related nodules were appeared within two weeks . the production of brown pigments on aged colonies of some isolates on ty or ty supplemented with l_tyrosine and copper sulfate revealed that these isolates of s. meliloti are melanin-producing rhizobia.based on the motility and sensitivity to antibiotics tests ,all of the isolates formed a reasonably homogenous group .however a few of them were able to produce an anti-microbial compound which was found to inhibit a number of isolates of s. meliloti .the compound did not suppress the growth of other bacteria . partial purification and spectrophotometery of the compound suggested that it likely belong to the antimicrobial polypeptides .considering on their physiological and biochemical properties ,none of the isolates were selected as a superior and competitive strain ,although based on nodulation efficiency , melanin and antimicrobial compounds production capability the isolate s. meliloti sm2 and sa23 were nominated to investigate in details. cyclotides are a fascinating family of plant-derived peptides characterized by their head-to-tail cyclized backbone and knotted arrangement of three disulfide bonds. this conserved structural architecture, termed the cyclic cystine knot, is responsible for their exceptional resistance to thermal, chemical and enzymatic degradation. cyclotides have a variety of biological activities but their insecticidal activities suggest that their primary function is in plant defense. in this study we determined the cyclotide content of the sweet violet viola odorata, a member of the violaceae family. we identified 30 cyclotides from the aerial parts and roots of this plant, 13 of which are novel sequences. the new sequences provide information about the natural diversity of cyclotides and the role of particular residues in defining structure and function. as many of the biological activities of cyclotides appear to be associated with membrane interactions, we used hemolytic activity as a marker of bioactivity for a selection of the new cyclotides. the new cyclotides were tested for their ability to resist proteolysis by a range of enzymes and, in common with other cyclotides, were completely resistant to trypsin, pepsin and thermolysin. the results show that while biological activity varies with the sequence the proteolytic stability of the framework does not, and appears to be an inherent feature of the cyclotide framework. the structure of one of the new cyclotides, cycloviolacin o14, was determined and shown to contain the cyclic cystine knot motif. this study confirms that cyclotides may be regarded as a natural combinatorial template that displays a variety of peptide epitopes most likely targeted to a range of plant pests and pathogens. furthermore, the inherent stability of the framework makes it an excellent scaffold for protein engineering applications. warfarin is the most widely prescribed anticoagulant drug for the prevention and treatment of arterial and venous thromboembolic disorders.because of large interpatient variability in the dose-anticoagulant effect relationship and a narrow therapeutic index careful dosage adjustment based on inr is essential. warfarin is available as a racemic mixture of two enantiomers,(s)-and (r)-warfarin. in contrast to (r)-warfarin, which is metabolized by multiple cytochrome p450s(cyps), including cyp1a2 and cyp3a4,(s)-warfarin, is predominantly metabolized to 7-hydroxywarfarin by polymorphic cyp2c9. since the potency of (s)-warfarin is much higher than that of (r)-warfarin, about 3-to 5-fold,any change in the activity of cyp2c9 gene is likely to have a significant influence on the anticoagulant response. previous in vitro findings revealed that certain variants in the cyp2c9 gene are associated with large interindividual differences in the pharmacokinetic and pharmacodynamic outcomes of warfarin therapy. three major alleles have been found to date in humans:arg144/ile359, and cys144/ile359 and arg144/leu359, and arg144/leu359, which have been designated cyp2c9*1 (wild-type), cyp2c9*2, and cyp2c9*3, respectively. we have investigated this polymorphism in iranians that has not been described previously. genomic dna was isolated from whole blood. for detection of cyp2c9*2, and cyp2c9*3 variants, a protocol based on pcr technique and endonuclease digestion with kpni, ava ii was used. in this research work, we have studied a group of 56 patients, in which warfarin therapy was initiated. recently new 21-residue antimicrobial peptides -arenicins were isolated from coelomocytes of marine polychaeta arenicola marina and their sequences were determined [1] . there are two isoforms of arenicins which differ only with single amino acid. these peptides have no structure similarity to any previously identified antimicrobial peptides. we have synthesized and estimated the antibacterial properties of arenicin-1: rwcvyayvrvrgvlvryrrcw. the linear peptide was prepared by solid phase method using boc-technology without any problem. however the cyclization caused the appreciable difficulties. the following methods of oxidation were used: oxygen of air, k3fe(cn)6 and hydrogen peroxide in aqueous or organic media. the best results were obtained by using hydrogen peroxide in methanol, but and in this case the yield of the aim peptide did not exceed 5%. synthetic arenicin had the same hplc profile and maldi-tof spectra as a natural molecule. the peptide showed an antimicrobial activity against gram-positive bacteria: peptidergic hormones and neurotransmitters are known to be produced by the specific cleavage of their precursor proteins that per se have no biological functions. the neutrophil-activating peptides we recently identified, however, are the peptides cleaved from mitochondrial proteins by proteolysis. therefore, we named them "functional cryptic peptides" because they are hidden in protein sequences. some of these peptides activate gi type of g proteins directly, and neutrophils are suggested to be stimulated by the direct (i.e., not via gpcrs) activation of g proteins. these peptides had features, in common, in their distributions of charged and hydrophobic amino acid residues, but homologies in their primary structures were not apparent. in the present study, we predicted functional cryptic peptides that activate g proteins, based on the distribution of charged and hydrophobic residues. receptors for these peptides were also investigated by the direct cross-linking experiments between peptides and their targeted proteins. the finding of functional cryptic peptides is expected to lead to the identification of novel signaling mechanisms where such peptides are involved in the regulation of bio-functions. the fragment 81-88 of the precursor of human interleukin-1alpha (pil-1α) (gk-vlkkrr) appeared to have more than 80% homology with corticotropin fragment 10-18 (gkpvgkkrr). we have previously synthesized the octapeptide gkvlkkrr (referred to as leucocorticotropin, lct) and found its high affinity binding to corticotropin receptors on various immunocompetent cells in human and mouse. in this study we investigated the interaction of lct with rat adrenal cortex membranes and the effects of lct on the level of 11-oxycorticosteroids (cs) in rat adrenal glands and plasma in vivo. lct was labeled with tritium by the high-temperature solid-state catalytic isotope exchange reaction to specific activity of 22 ci/mmol. receptor binding studies revealed that tritium-labeled lct bound with high affinity and specificity to corticotropin receptor on rat adrenal cortex membranes (kd = 2.2 nm). lct at concentrations of 0.1 -1000 nм was found to have no influence on the adenylate cyclase activity in adrenal cortex membranes, while intranasal injection of lct to rats at doses of 10 -50 microg/kg was found to inhibit the secretion of cs from the adrenals to the bloodstream. thus, lct is an antagonist of corticotropin receptor. comarin derivatives such as warfarin are prescribed widely for treatment and prevention of thrombosis. warfarin is the widespread oral anticoagulant drug employed, but its required dose is highly variable both inter-individually and inter-ethnically. so it is desirable to develop strategies to predict the warfarin dose response in patients before initiation of anticoagulation. the vitamin k-dependent γ-carboxilation system, consists of the vitamin k-dependent γ-carboxylase, which requires the reduced hydroquinone form of vitamin k1 as a cofactor and the warfarin sensitive enzyme vitamin k1 2,3-epoxide reductase (vkor), which produces the cofactor. warfarin exerts its anticoagulant effect by inhibiting the vitamin k epoxid reductase enzyme complex (vkor) that recycles vitamin k1 2, 3-epoxide to vitamin k1 hydroquinone. a component of the vkor termed vkorc1, has now been identified as a therapeutic target site of warfarin. point mutations were identified within the gene encoding vkorc1 in individuals who required large doses of wafarin to maintain therapeutic anticoagulation. however the relationship between the primary structure of vkorc1 and the mechanism of action of warfarin is poorly understood. in previous works we have shown that naturally occurring functional protein fragments affect cell proliferation [1] . their mechanisms of action involve receptors of "classical" regulatory peptides, or are non-receptoric [1] . among protein kinases involved are pka, camkii, mapk [2] . in organism bioactive functional protein fragments could participate in maintenance of tissue homeostasis. in present work, homeostatic potential of functional protein fragments was studied in compare with classical regulatory peptides. the panel of test substances was formed, including signal transduction modulators (pka, pkc, ca2+-channel activators), classical regulatory peptides (bradykinin, somatostatin, met-enkephalin, endothelin, neurotensin) and fragments of functional proteins (β-actin fragments from (75-90) and (69-77) segments; valorphin (β-globin (33-39)); neokyotorphin (α-globin (137-141); short acidic peptides from multiple precursors). their activity was tested in cultures derived from similar sources but differing in transformation degree (e.g., mouse embryonic vs. tumor fibroblasts) and/or culturing conditions. the factors most affecting cell sensitivity to the test substances were (in order of the importance decrease): (1) cell type; (2) transformed vs. normal phenotype; (3) cell density; (4) serum supply. activity of fragments of functional proteins, showing general correlation with other test substances, was more influenced by the culturing conditions (i.e., cell population status). thus, fragments of functional proteins could be regarded as partners of "classical" homeostasis regulators, playing role of finer tuners of tissue proliferative status. the study was supported by ras presidium programme "molecular and cell biology" histone-like proteins in bacteria are small basic proteins that contribute to the control of gene expression, recombination and dna replication. they are also an important factor in compressing the bacterial dna in the nucleoid. among the hlps, hu protein is attracted to dna containing structural aberrations such as four way junctions or single stranded lesions. this protein plays an important role in binding as a dimer and bending dna. it also contributes to the beginning of the dna replication. in this study we showed that a 10-kda protein, probably hu exists in halobacillus karajiensis which is a novel gram positive moderate halophile bacteria that was recently isolated from surface saline soil of the karaj region, iran. since hu is purified and characterized in e.coli we used this bacteria as the control in this study. the 10-kda protein extraction was carried out by using pca 5% which is normally used for extracting histones from eukaryotic cells. the results of running the protein extracts on sds-page demonstrated a band around 10-kda which was seen in protein extracts of this protocol. these results supported the hypothesis of the existence of a 10-kda protein in halobacillus karajiensis. sufficient oxygen and nutrient delivery is a necessity for tumors. when oxygen supply decreases, tumors initiate growth of new blood vessels. low grade astrocytomas, a class of malignant brain tumors, grow along the existing vessels in a process called co-option. hypoxia is induced in the progression from grade iii to grade iv astrocytomas (glioblastoma multiforme, gbm) which in turn triggers the formation of a new and distinct tumor vasculature. the new vessels formed by tumor-triggered angiogenesis differ by molecular composition from their normal vascular counterparts. we are utilizing phage displayed peptide libraries to identify peptides that specifically home to either co-opted or angiogenic brain tumor vessels. furthermore, we aim at characterizing differentially expressed endothelial markers (receptor molecules) to get a better understanding of the molecular changes in the vasculature. several rounds of in vivo biopanning was performed in mouse models of astrocytomas to isolate a phage pool that has up to a hundred-fold homing to low grade tumor lesions. out of the selected pool we discovered peptides capable of homing and accumulating to the tumor islets and co-opted vasculature. the homing potential of our newly identified peptides has shown to be highly specific for clusters formed by the tumor cells and co-opted "early" vessels within these palisades. these homing peptides represent promising candidates to selectively target co-opted vessels and tumor lesions in the brain and act as lead compounds in identification of surface molecules (receptors) differentially expressed by co-opted tumor vessels. the αvβ3 integrin receptors play an important role in human tumor metastasis and growth. the inhibition of these receptors by antibodies or by cyclic peptides containing the arg-gly-asp( rgd) sequence may be used as selectively treatment to suppress the disease. our research group has previously described that the formal introduction of a single carbon atom to bridge the cα (i) and n(i+1) contiguous residues of a linear or cyclic peptide leads to α-amino-β-lactam peptidomimetics containing predictably placed β-turn and γ-turn motifs, respectively. the combination of these results with the well-known capacity of rgd tripeptide for inhibition of the biological answer in integrin led us to the design of the following cyclic peptide. the adhesion and cell-growth "in vitro" assays using human umbilical vein endothelial cells (huvec), as well as "in vivo" assays with xenograph mice revealed that the rgd peptidomimetic was active to micromolar concentrations, slightly better than the reference compound in this field: cilengitide®. whole saliva is composed of secretions from parotid, submandibular and sublingual glands, and smaller ones from saliva of minor salivary glands (e.g. palatal and labial). saliva contains a variety of proteins and polypeptides. one of them is statherin, a multifunctional 43-amino acid residue, phosphominiprotein. this peptide is present in human parotid and submandibular saliva . the aim of our study was to investigate the stability of statherin in extracts of the major salivary glands. submandibular, sublingual and parotid gland tissues were obtained at autopsy 12 h after death. samples of the gland tissues were homogenized, centrifugated (30,000 g, 30 min., 4 c) and the supernatants were frozen and stored at -70 c prior to analysis. synthetic statherin was added to the supernatants before analysis (45 microgram/ml). the samples were analysed for the presence of the peptide by the matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (maldi-tof ms}technique and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds page). statherin has been found to be decomposed in extracts of parotid and submandibular glands and also in the extract of sublingual glands. the dramatic increase in research for new anthrax therapeutic approach was prompted by potential use of the causative agent of anthrax bacillus anthracis as a biological weapon. anthrax toxin consists of three proteins, the protective antigen (pa) and the two enzymes lethal factor (lf) and edema factor (ef) that are carried through the membrane of the target cell upon binding to specific site on the membrane receptor-bound pa. lethal factor and edema factor were found to cooperate to promote immune evasion of the bacterium. here we describe the production of peptide inhibitors of pa-lf binding, obtained by selecting pa-binding peptide by a competitive panning of a phage peptide library, using recombinant lf. we selected several 12 mer peptides, which were synthesized in tetra-branched multiple antigen peptide (map) form, inducing resistance to proteolytic degradation (1) and maintaining biological activity of phage peptides. lead tetra-branched peptides were systematically modified by progressive shortening and residue randomization, to obtain an increase of peptide affinity and inhibitory efficiency. affinity maturation of lead sequences enabled selection of a peptide which has an ic50 at least one log lower that any other lethal-toxin-inhibiting peptide described so far and is effective for in vivo neutralization of anthrax toxin activity (2) . the same peptide can also efficiently inhibit the binding of ef to pa and ef-induced camp increase in different cell lines. microtubules are dynamic polymers that have important roles in eukaryotic cellular processes such as signal transduction, cell polarity, vesicular transport and chromosomal movement. the dynamic behavior of microtubules has been studied both in vivo and in vitro. the effect of arsenic trioxide on microtubule polymerization has been studied under in vivo experimentation shown that it inhibits formation of mitotic bundles. we studied the mechanism of arsenic trioxide effect on polymerization of microtubule protein purified from sheep brain in vitro. microtubule polymerization has been conducted by adding 1mm gtp to purified tubuline in pem buffer at 37oc for 30 minutes and simultaneously followed by measuring turbidity (350 nm). the results shown that lag time of polymerization (nucleation step) is affected by increasing concentrations of arsenic trioxide from 0-5 micromolar. moreover the rate of elongation step was decreased exponentially by increasing arsenic trioxide concentration. electron micrographs also showed microtubules length decrement due to arsenic trioxide. the results have shown the inhibitory effect of arsenic trioxide on microtubule polymerization via its effect on nucleation step as well as elongation rate. background and aims: alzheimer's disease (ad) is the major cause of dementia among the elderly. the increase in life expectancy worldwide demands new therapies for ad urgently. self-association of the amyloid ß-protein (aß) into neurotoxic assemblies, a seminal event in the etiology of ad, is considered to follow interactions of the c-terminus of the 42-residue form of aß (aß42). we hypothesized that molecules with high affinity for the c-terminus of aß42 will disrupt aß42 oligomerization. a series of c-terminal fragments (ctfs) of aß42, aß(x-42) with x = 28-39, has been prepared to study their potential to inhibit aß42 oligomerization and neurotoxicity. methods: attenuation of aß42 assembly by ctfs was studied by quantitative analysis of oligomer size distributions using a photo-cross-linking assay followed by sds-page. biological activity of ctfs themselves and as inhibitors of aß42-induced neurotoxicity was assessed by mtt reduction assay using differentiated pc-12 cells. the structure of the ctfs was studied by circular dichroism (cd) spectroscopy and ion mobility spectrometry-mass spectrometry (ims-ms) coupled with molecular dynamics (md) simulations. results: ctfs were found to inhibit aß42 oligomerization in a length dependent manner with minimal or no toxicity of the ctfs themselves. certain ctfs were found to inhibit aß42-induced neurotoxicity. cd spectra indicate that increasing peptide length results in growing ß-sheet content. structures based on experimentally determined cross-sections support the existence of a previously proposed turn around residues gly37-gly38. the data suggest that aß42 ctfs can serve as lead compounds for development of peptidomimetic drugs for treatment and prevention of ad. background and aims: human kallikrein hk2 is a prostate specific serine protease, which expression level is elevated in aggressive human prostate cancer suggesting a possible role in a tumour growth and spreading. since hk2 protease is highly prostate specific, inhibition of its activity is a possible method to prevent tumour growth without interfering the function of the other proteases. we have identified hk2 specific linear peptide inhibitor by using phage display techniques. in order to design peptide for in vivo studies we tested the protease stability of the linear and the cyclic forms of the peptide. methods: the prerequisite of the binding was studied by using conventional ala-replacement method and the most optimal sequence was selected for further studies. the stability of the original linear form, acetylated form, peptide with cystein bridge and head-to-tail cyclic peptide was tested with modified trypsin (sequencing grade) and with human plasma. results: both linear versions and peptide with cystein bridge were unstable and were degraded during the first 30 minutes in both stability tests. head-to-tail form of the peptide was stable in both tests during the first 180 minutes. conclusions: since our peptide contains arginine there was a possibility that our peptide is sensitive to trypsin and other serum proteases. indeed both linear and one cyclic from degraded in our tests. only head-to-tail peptide was stable during the first 3 hours suggesting protease resistant folding. background and aims: a large number of anticancer agents has been developed in recent years. however, these agents have very little or no specificity which leads to systemic toxicity. among them paclitaxel is considered to be one of the most important drugs in cancer chemotherapy; however, this agent has also lack of selectivity to the tumor tissue. therefore, development of tumor-targeting prodrug is highly promising. methods: to activate cytotoxic agent specifically at the tumor tissue, we developed a new prodrug strategy based on o-n intramolecular acyl migration, which is a well-known reaction in peptide chemistry, and photodynamic therapy. results: we synthesized a prodrug which has a coumarin derivative conjugated to the amino acid moiety of isotaxel (o-acyl isoform of paclitaxel). the prodrug was selectively activated by visible light irradiation (430 nm) leading to cleavage of coumarin. finally, paclitaxel was released by subsequent o-n intramolecular acyl migration. conclusion: we synthesized and evaluated a novel type of paclitaxel prodrug. this prodrug showed promising kinetic data. therefore, we believe that photoactivation can be promising novel strategy for design of tumor-targeting prodrugs. the search of new immunosupressants, exhibiting the mechanism of action characteristic for cyclosporine a (csa) and fk-506 is an important challenge for medicinal chemistry. cyclolinopeptide a (cla) natural cyclic nonapeptide [cyclo(leu-ile-ile-leu-val-pro-pro-phe-phe)] possesses a strong immunosuppressive activity comparable with that of csa in low doses. the possibility of practical application of cla as a therapeutic agent is limited due to its high hydrophobicity. it has been suggested that the tetrapeptide sequence pro(6)-pro(7)-phe(8)-phe(9) is responsible for the interaction of the cla molecule with the proper cellular receptor. in order to evaluate the role of this tetrapeptide unit for biological activity of native peptide, we decided to modified this fragment. in this communication we present linear and cyclic cla analogues in which phenylalanine residues in position 8 and/or 9 have been replaced with amphiphilic; alphahydroxmethylphenylalnine 1 or homophenylalanine 2. the synthetic strategy and biological activity will be evaluated. resistance to currently used small molecule antibiotics develops at an alarming rate. while resistance to β-lactams in clinical isolates is primarily due to hydrolysis of the ring by β-lactamases, when bacteria develop resistance to fluoroquinolones or aminoglycosides, the sequences of the target biopolymers are altered. earlier we developed a family of antibacterial peptide derivatives that kill bacteria by inhibiting protein folding and are active in animal models of infection. in the current study we examined the synergy between antibiotics acting by different modes of action. inhibition of properly folded active resistance enzymes was completely efficacious to recover the activity of amoxicillin, a β-lactam antibiotic against strains that were originally resistant to this molecule. some activity of ciprofloxacin was also recovered by reducing the load of the induced self-defense dnak protein, but the synergy between the antibacterial peptide and the fluoroquinolone did not yield full bacterial killing. the mode of action of the synergy is indeed inhibition of protein folding because no such effect could be observed with kanamycin where resistance involves changes in the target protein sequence. as opposed to current β-lactamase inhibitors and combination therapies that work against only a limited number of strains, inhibition of all protein folding in bacteria is a universally applicable treatment option. elimination of resistance to β-lactams by proline-rich peptide derivatives may represent a viable avenue to give second life to these antibiotics for which large stockpiles are available for pharmaceutical companies in both patented and generic forms. the integrin αiibβ3 is the major integrin-adhesion receptor on platelets. in unstimulated platelets αiibβ3 is present in a resting conformation state. upon platelet activation by agonists, αiibβ3 receives intracellular signals (inside-out signaling) that allow its rapid conversion to a high-affinity state capable of binding soluble ligands, resulting in platelet aggregation. the intracellular signals include proteins that bind to the cytoplasmic tails of the two subunits α and β of the integrin, or integrin-associated membrane proteins. in vivo charge swapping mutation studies suggested that αiib and β3 tails have a direct site of interaction between αiib (r995) and β3 (d723). peptides derived from the cytoplasmic tail sequences can specifically induce or block αiibβ3 activation in platelets. the aim of this study is to develop peptide analogues based on the cytoplasmic tail sequences of both αiib and β3 subunits that could inhibit platelet thrombus formation by specifically disrupting the inside-out signaling pathway. peptide analogues of the αiib and β3 subunits spanning the sequences αiib-989-1008, αiib -997-1003, αiib -997-1008, αiib-1000-1008 and β3-743-750, β3-743-756, β3-749-756 were synthesized in their free state, palmitoylated and/or tagged with the tat fragment 48-60 and carboxyfluorescein-labeled, in order to investigate their membrane permeability, as well as their inhibition of the platelet aggregation. inflammatory pain begins when noxious stimuli (thermal, chemical or mechanical) excite sensorial neurons called nociceptors. the activation of nociceptors leads to the opening of some ionic channels and depolarization of the cell membrane. one of these channels is trpv1, which is directly implied in thermal hyperalgesia associated to inflammation. in previous work it has been found that peptoid h-arg-15-15c ( fig. 1) inhibits the activation of trpv1 by blocking the pore entrance. however, this compound showed toxicity in vivo. the aim of our work is the design and synthesis of new compounds, based on the structure of h-arg-15-15c, with better therapeutic properties. we synthesized some new non-competitive antagonists of trpv1 that exhibit notable anti-inflammatory and analgesic activity in vivo. th. skarlas, e. panou-pomonis, d. krikorian, m. sakarellos-daitsiotis, c. sakarellos erf is a transcriptional repressor with tumor suppressor activity regulated by the ras/erk signaling pathway. it has been shown that erf interacts with, and is phosphorylated by erks in vitro and in vivo. this phosphorylation determines its subcellular localization and biological function. erf exhibits a high degree of specificity and sensitivity for erks. the major objective of our study is to provide proof of principal for a specific anti-cancer approach targeting the ras-pathway, which is commonly activated in human tumors, via the stimulus of the downstream effector erf. this will be attained by modeling specific peptide inhibitors that block the erf phosphorylation and inactivation by the ras/erk signaling pathway. we present the design and synthesis of peptide inhibitors incorporating the fsf and fkf motifs, known to play a critical role in the erf/erk interaction, in their free forms or conjugated to a carrier. ubiquitinium is a well known mechanism in protein degredation of eukaryotic cells ,in which many obsolte and corrupted three dimentional structure protein ,become marked by covalent attachment of ubuquitin through a multi-step enzymatic pathway.ubiquitin is a small ,8.5 kda peptide of 76 amino acid residues that targets such substrtes for proteolysis in proteasome .recnt studies showed that an extra cellular ubiquitination process also taking place in the epididymes of humans and other animals marks protein on the surface of the defective sperm .it appears that structurally and functionally defective sperm become surface ubiquitinated by epididymal epithelial cells. a certain portion of ubiquitin -labeled sperm is phagocytosed and the remaining is ejaculated .hence ubiquitin on the sperm surface could be a good marker of semen quality control in men. the aim of present study is to purify ubiquitin from packed blood cells , to produce and purify antiubiquitin antibodies,to design an immunofluorescence assy for detection of defective sperm, to compare the percentage of ubiquitinated sperm in oligoasthenotertozoospermia and normozoospermia and finally to determine correlations between sperm parameters and sperm ubiquitination. p. vakalopoulou, ch. anastasopoulos, g. stavropoulos, s. yiannis c-terminal analogues of substance p (sp) have been studied for their ability to prevent tumor growth or the proliferation of several cancer cell lines. the incorporation of damino acids into the sequence of sp and n-methylation of peptide bonds have shown to protect sp from the action of plasma and tissue peptidases. aiming to design and prepare more potential antagonist of cancer cells proliferation and taking into account that all the metabolites of the c-terminal hexapeptide analogue [arg6, d-trp7,9, mephe8]sp6-11 (antagonist g) possess the n-me group and d-trp residue, we proceeded to the synthesis of peptoid-peptide hybrids. they are oligomeric peptido-mimetics containing the residue [-ν(bzl)-ch2-co-]=(nphe). the incorporation of n-substituted glycine in peptide chains has been proved to improve their stability against proteases and give biologically active peptides. thus, the tetrapeptoid-peptide hybrids h-arg1-d-trp2-nphe3-d-trp4-oh and h-d-trp1-nphe2-d-trp3-leu4-oh, corresponding to metabolites of antagonist g and also the hexapeptoid-peptide hybrids glp1-d-trp2-νphe3-d-trp4-leu5-glu(obzl)6-νη2 and glp1-d-trp2-νphe3-d-trp4-leu5-glu(obzl)6-oh have been synthesized. the latter have incorporated the amino acid residues glp at the n-terminal and glu(obzl) at the c-terminal of the analogue, which have shown to give to the analogues increased resistance and biological activity. all the products were purified (hplc), identified (esi-ms) and set about for study their biological properties and activity against cancer cells proliferation. a chemokine receptor cxcr4 has multiple critical functions in normal and pathologic physiology. cxcr4 is a gpcr that transduces signals of its endogenous ligand, cxcl12 (stromal cell-derived factor-1, sdf-1). the cxcl12-cxcr4 axis plays an important role in the migration of progenitors during embryologic development of the cardiovascular, hemopoietic, central nervous systems and so on. this axis has recently been proven to be involved in several problematic diseases, including hiv infection, cancer cell metastasis, leukemia cell progression, rheumatoid arthritis (ra) and pulmonary fibrosis. thus, cxcr4 is a great therapeutic target to overcome the above diseases. fourteen-mer peptides, t140 and its analogs, were previously found to be specific cxcr4 antagonists that were identified as hiv-entry inhibitors, anti-cancer-metastatic agents, anti-chronic lymphocytic/acute lymphoblastic leukemia agents and anti-ra agents. cyclic pentapeptides, such as fc131 [cyclo(d-tyr-arg-arg-l-3-(2-naphthyl)alanine-gly)], were previously found as cxcr4 antagonist leads based on pharmacophores of t140. in this symposium, we would like to report the development of low molecular weight cxcr4 antagonists involving fc131 analogs and other compounds with different scaffolds including leaner-type structures. erythropoietin (epo) controls the proliferation and differentiation of red blood cells. it activates epor by inducing dimerization and reorientation of two receptor chains. peptides mimicking the action of epo, epo mimetic peptides (emp), have been discovered by phage display, interacting with the receptor on the active site and competing with the hormone [1] . another peptide, epor derived peptide (erp), was reported to activate the receptor through an alternative site distant from the hormone binding site, and to have synergic action with epo [2] . we report the design of new synthetic epo-r agonists by dimerization of active peptides. pegbased polyamide linkers of precise length were used to link the molecules, using oxime chemistry [3] . these peptides include emps that have been homo-dimerized through their n-or c-terminus. a hetero-dimer of one emp and one erp peptides was also created. biological characterization of the molecules is currently under investigation. [ the envelope spike (s) glycoprotein of the severe acute respiratory syndrome associated coronavirus (sars-cov) mediates the entry of the virus into target cells. recent studies point out to a cell entry mechanism of this virus similar to other enveloped viruses, such as hiv-1. as it happens with other viruses peptidic fusion inhibitors, sars-cov s protein hr2 derived peptides are potential therapeutic drugs against the virus. it is believed that hr2 peptides block the six-helix bundle formation, a key structure in the viral fusion, by interacting with the hr1 region. it is a matter of discussion if the hiv-1 gp41 hr2 derived peptide t20 (enfuvirtide) could be a possible sars-cov inhibitor given the similarities between the two viruses. we used fluorescence spectroscopy techniques to test the possibility of interaction between both t20 (hiv-1 gp41 hr2 derived peptide) and t-1249 with s protein hr1 and hr2 derived peptides. our biophysical data show a significant interaction between a sars-cov hr1 derived peptide and t20. however the interaction is only moderate (kb = (1.1±0.3) × 105 m-1). this finding shows that the reasoning behind the hypothesis that t20, already approved for clinical application in aids treatment, could inhibit the fusion of sars-cov with target cells is correct but the effect may not be strong enough for application. [1] were used to investigate the structure, dynamics and thermodynamics of the known complex between erythropoietin mimetic peptides (emp) and erythropoietin receptor (epor). with gromacs 3.2 bioinformatics software, we have obtained from the known emps about the key functional amino acids required for effective epo mimetic action. then we systematically altered the amino acids in those peptides, and simulated the complex to observe the differences between the altered peptides with the original ones. based on these results, we designed new emps of potential significance. in order to fast identify the mimetic action of these new peptides, we synthesized these peptides and labeled the epor binding peptide (ebp) with quantum dots [2] , to study the binding of these new emps to epor. our results illustrate a principle for fast identifying receptor-specific sites importance for receptor internalization, and for enhancing sensitivity to hormones and other agonists. blood vessel formation largely contributes to the pathogenesis of numerous diseases, including ischemia and cancer [1] [2] . in this regard therapeutic strategies aim to stimulate vascular growth in ischemic tissues and suppress their formation in pathologies like in tumour and diabetic retinopathy. placental growth factor (plgf), an homolog of vascular endothelial growth factor (vegf), (42% amino acid sequence identity), stimulates angiogenesis and collateral growth in ischemic heart and limb. whereas vegf exerts it biological function through the binding to both vegf receptor-1 (vegfr-1or flt1) and vegfr-2 (or kdr) plgf binds specifically to flt1. the complex plgf/flt1 constitutes a potential candidate for therapeutic modulation of angiogenesis and inflammation [3] . the binding between plgf and flt-1 has multipunctual features [4] and potential antagonist must have a sufficient molecular surface to spatially distant contact points. we have used an elisa-like screening assay to select antagonists of plgf/flt-1 complex from a large random library of tetrameric unnatural peptides (complexity: 3^30=27.000 molecules) identifying two active molecules with an about 10 m ic50. the relative stability of identified peptides were assessed in human serum and their inhibitory properties were tested in a capillary-like tube formation assay performed with human umbilical vein endothelial cells (huvec the αvβ3 integrin is a cell adhesion receptor involved in angiogenesis and tumor cell invasion. the tripeptide motif rgd is the αvβ3 minimal recognition sequence and many rgd-containing peptides have been investigated as radiopharmaceuticals for targeting angiogenesis and tumor metastatic phenotype. since rgd sequence binds also to other integrins, the aim of the present study was to develop and characterize a selective αvβ3 ligand suitable for imaging. a novel peptide containing the rgd loop covalently linked to an echistatin domain (crgdechi) was designed, synthesized and then tested for selective binding to αvβ3 integrin. a panel of peptides were used for comparison. adhesion assays showed that the novel peptide was able to inhibit adhesion of αvβ3 overexpressing cells but not αiibβ3 and αvβ5 overexpressing clones. in conclusion the novel peptide showed a high affinity and specificity for αvβ3 integrin. the design of new molecules, based on the lead compound presented here, is currently ongoing with the aim at developing novel anticancer drugs and/or new class of diagnostic noninvasive tracers as suitable tools for αvβ3 -targeted therapy and imaging. background and aims: short peptides like leu-pro-phe-phe-asp (lpffd) and leu-pro-tyr-phe-asp-amide (lpyfda) can influence the structure and aggregation of ß-amyloid peptides. soto's pentapeptide lpffd has been published as a ß-sheet breaker (bsb). it is necessary to gain more information about the nature of the interaction of aß and the pentapeptides mentioned above for the understanding of their action and for the possible development of future therapeutic agents. methods: in this study radioligand binding assay, diffusion ordered nmr spectroscopy, dynamic light scattering, circular dichroism and ft-infrared spectroscopy was used. results: it was shown by radioligand binding assay and diffusion ordered nmr spectroscopy that both pentapeptides bind to aggregated aß. dynamic light scattering, circular dichroism and ft-infrared spectroscopy revealed, that after the treatment of the aß with the pentapeptides aß fibrils are still present. conclusion: both peptide can bind to aß and can cause small conformational changes of aß, however, they cannot prevent completely the formation of aß fibrils in 50-100 micromolar concentration using 1:1 molar ratio of aß and the bsb peptide. peptide arrays are convenient tools for the analysis of antibodies, protein binding domains and to address other biological questions. here we present a new method to produce identical copies of arrays on microscope slides. the peptides are synthesized on modified cellulose-discs, using a variation of the spot-method introduced by ronald frank more than 10 years ago [1] . the new array format overcomes several limitations of the spot-method, e.g. the low throughput with only one copy of the library and the large sample volumes that are needed for membrane incubations. for the presented arrays modified cellulose discs with covalently bound peptides are dissolved after synthesis. the resulting solutions can be spotted onto glass slides by conventional spotting techniques. three dimensional layers of cellulosepeptide molecules are formed on the surface of the supports used for spotting. a virtually unlimited number of identical arrays can be printed and assays are performed with a sample volume of 100 µl or less. as application example we show mapping experiments of the streptavidin recognition site with a peptide library containing histidine-proline motives. because of the much higher peptide loading compared to conventional arrays, the formed 3-dimensional structure might be superior for protein-interaction studies with even low binding constants. [ the interaction between the cap binding protein, eukaryotic initiation factor (eif) 4e, and the scaffolding protein eif4g is critical for the formation of the heterotrimeric eif4f translation initiation (ti) complex (eif4e/eif4g/eif4a). elevated levels of eif4e and eif4g found in several human solid tumor cancers and the induction of malignant transformation in animal models by overexpression of eif4e and the reversal of this phenotype by treatment with anti-sense rna, suggest the importance of the eif4e/eif4g interaction in the excessive translation of oncogenic proteins. eif4g binds to eif4e through a conserved eif4e-binding motif yx4l (non-specified (x) and hydrophobic ( ) amino acids) that interacts with an hydrophobic hot spot on eif4e. we report here the identification of a putative eif4e anionic exosite that is distinct from the hot spot and contributes to the binding of eif4g-derived ligands. our strategy focuses on in situ eif4e-templated click reaction-mediated assembly of hybrids comprised from an anchoring minimal eif4g-derived peptide fragment, which binds to the hot spot, and a series of complementing positively charged fragments targeting the anionic exosite. we synthesized a training set of [1, 2, 3] triazole-containing hybrid peptides that are potent inhibitors of eif4e/eif4g interaction. moreover, we achieved in situ eif4e-templated assembly of these hybrids from the corresponding fragments via click reaction in the absence of cu(i) catalysis. as such, we demonstrate a proof-of-concept for a new paradigm in the development of inhibitors of protein-protein interaction merging click reaction with fragment-based and in situ target-templated approaches. goodpasture disease is an autoimmune pathology caused by the accumulation of reactive autoantibodies against the alpha-3 of collagen iv. goodpasture antigenbinding protein (gpbp) is a ser/thr protein kinase that phosphorylates the alpha-3 chain and might be important in human autoimmune pathogenesis [1] . we are carrying out in our laboratories the biophysical and functional characterization of gpbp protein. in the presence of some proteins and at specific experimental conditions, gpbp participates in structurally ordered intra-and inter-protein aggregation processes. structure prediction programs identify four different domains for gpbp: an n-terminal domain showing pleckstrin homology (ph domain); a central domain with high tendency to form coiled-coils; a domain with ww features; and a c-terminal start domain ('star-related lipid-transfer'). using the tango algorithm [2] , we have identified several aminoacid sequences in the gpbp start domain of vertebrates with high tendency to participate in protein aggregation. in this work we present the synthesis and structural characterization of a collection of peptides derived from the sequences described above. we recently developed a combinatorial library screening protocol to identify hpq-containing cyclopeptides that bind streptavidin more tightly than its linear analogues. the relative affinities in ic50 of these structurally constrained ligands and its linear counterparts were measured by a captured enzyme-linked immunosorbent assay. however, their intrinsic binding kinetics remained to be elucidated. in this work, surface plasmon resonance (spr) was employed to directly determine the kinetics and thermodynamics of the ligands binding to a streptavidin chip. solid-phase peptide synthesis was carried out using standard fmoc chemistry. spr experiments were carried out using biacore3000 optical biosensor. streptavidin was immobilized onto a cm5 sensor chip using the standard amine coupling procedure. the equilibrium dissociation constants and kinetic on/off rates of n-to-side chain and n-to-c cyclopeptides were deduced by scatchard analysis and computational simulation, respectively. it was found that both cyclopeptides exhibited similar binding kinetics and bound streptavidin far more avidly than its linear form (1000-fold). in addition, the reversed (qph) linear and cyclic peptidyl ligands were hardly recognized by streptavidin. not only the binding specificity was distinguished qualitatively, but also the entropic advantage acquired by the pre-organized conformation over its linear analogues was demonstrated quantitatively by spr in this study. the mutation of tumour suppressor genes in the progression of cancer is well characterized. for example, p53 is found to be mutated in approximately 50% of cancers and the loss of this proteins activity has been shown to lead to the deregulation of cell growth and apoptosis. the potential of peptide aptamers to inhibit protein/protein interactions in a highly specific manner makes them very attractive as research reagents or as target validation tools in anti-cancer drug discovery. more interestingly, these molecules have the potentially to inhibit the activity of proteins which are key regulators of cancer cell growth and therefore could act as synthetic tumour suppressor proteins. we used peptides based on known protein/protein interactions, as well as peptides isolated using display technologies, for the design of protein aptamers that were used to analyze pathways critical in controlling cancer cell growth. a range of scaffolds were used to present these peptides in an effort to optimize the peptides activities. data relating to the activity of these peptide aptamers in vitro as well as in cellular systems will be discussed. the cyclic undecapeptide urotensin ii (u-ii) is the endogenous agonist for the u-ii receptor (ut), a gq coupled gpcr. current views suggest that binding by agonist, but not antagonist, leads to induction of stabilization of an active receptor conformation. we have previously probed the interactions of urotensin ii with rat ut (rut) using a series of photolabile u-ii analogues containing p-benzoyl-l-phenylalanine (bpa). it was found that the c-jun n-terminal kinases (jnks) are important mitogen-activated protein kinases. these ser/thr protein kinases are activated by various growth factors, cytokines, and cellular stresses. jnks have been shown to play a key role in phosphorylation of proteins in signal transduction of different diseases including cancer, neurodegenerative, cardiovascular, and inflammatory diseases. therefore, these enzymes are considered as important therapeutic target proteins. the interactions of jnk with peptides are of special interest for development of novel specific atp-noncompetitive inhibitors. interactions of this kinase and its mutants with various substrates were demonstrated in vivo using yeast ras-recruitment system. bioinformatical tools have been developed to predict optimized binding peptides as well as to correlate sequence position and amino acid with binding effiency to extract binding determinants. biomolecular interaction analysis have been performed for selected peptide sequences using surface plasmon resonance (spr) technology. real time measurements of the binding of peptides to the different isoforms jnk2 and jnk3 resulted in the determination of affinities as well as kinetic constants for association and dissociation. experimental results and their bioinformatic analysis are discussed with respect to critical features of potential atpnoncompetitive inhibitors. the b-domain of is one of the five nearly homologous domains of staphylococcal protein a. this domain contains three alpha-helices which are assembled in an anti parallel three-helix bundle. the b-domain binds the fc region of mammalian immunoglobulins through the n-terminal fragment that contains two alpha-helices. the c-terminal helix does not interact with fc but it is necessary for the correct folding and immunoglobulin recognition of the b-domain. to search for new peptide analogues of the c-terminal helix that bind the n-terminal fragment, a ¨one-bead one-compound¨ library of 300 peptides was designed based on the sequence of the c-terminal helix. active peptides were obtained after incubation of the library with the n-terminal fragment and rabbit immunoglobulin g labelled with fluorescein. new peptides were found and their sequences identified by maldi tof-tof mass spectrometry. the synthesis of the two most active peptides was carried out and the binding with the n-terminal fragment was confirmed by cd spectroscopy. the nterminal fragment peptide showed an increase in helicity when the c-terminal wild type peptide or some analogues were present in solution. the complete domains with the c-terminal fragment mutations were synthesized and structurally characterized by cd and nmr spectroscopy. the wild type and the new mutants adopt predominantly an alpha-helical structure. the interaction between rabbit immunoglobulin g and the wild type b-domain and the new analogues was investigated using surface plasmon resonance. although compared with the wild type, the mutants exhibited different kinetics, they were able to bind the immunoglobulin with high affinity. a. jaśkiewicz, e. bulak, h. miecznikowska, k. rolka sfti-1, a strong trypsin inhibitor, was isolated in 1999 from seeds of sunflower. it is homodetic 14-amino-acid-residue peptide containing a disulfide bridge. because of its small size and strong trypsin inhibitory activity, this inhibitor became an interesting model for studying enzyme -inhibitor interactions. sfti-1 possesses one reactive site located at the lys5-thr6 peptide bond and therefore is able to interact with the enzyme in a 1:1 stoichiometry. in this report we describe chemical synthesis and kinetic studies of a series of sfti-1 analogues containing double sequences of the wild inhibitor. their structures contain combinations of disulfide bridges and/or head-to-tail cyclization. each of these analogues contains two trypsin-specific reactive sites. we expect that kinetic studies should answer the question whether such dimeric analogues are able to interact simultaneously with more then one trypsin molecule and how this fact affects their inhibitory potency. in addition, we alsopresenttwo analogues in which we substituted the disulfide bridge with a carbonyl one. since carbonyl bridge has not been previously introduced into molecules proteinase inhibitors, we decided to check its impact on the activity and proteolytic stability of such modified analogues. ubiquitination, the covalent attachment of one or multiple polymerized ubiquitins is a post-translational modification of proteins, which has manifold functions. it mainly determines the protein for degradation, but also activation, deactivation or substrate alteration. due to its ubiquitinous distribution in all eucarionts no high-affinity antibodies could be originated. highaffinity ligand peptides are of interest to study ubiqutination. based on bioinformatical considerations and investigations of ubiquitin-interacting proteins short peptide sequences were selected. by using a peptide array specific ubiquitin binding was monitored and quantified with label free detection based on reflectometric interference spectroscopy (rifs). the results from rifs were confirmed by detection of binding in solution with fluorescence correlation spectroscopy (fcs) using carboxyfluorescein and s0387-labelled peptide amides. binding constants were determined by isothermal calorimetry (itc) and rifs. finally 1h,15n-nmr chemical shift analyses of the peptides with the highest affinity were carried out, which allowed the localisation of the interaction site of ubiquitin with the peptide the results from all four methods correlated very good. they showed fast equilibria within 30 s and binding constants down to the low micromolar range. nmr results revealed hints for discrimination possibilities between lys48 and lys63 polymerized ubiquitins. ( 101f is a potent neutralizing mab that binds the human respiratory syncytial virus (hrsv) f protein and is a promising candidate for clinical development. the majority of neutralizing antibodies to hrsv f protein map to two regions of the protein designated site ii and site iv,v,vi. to further characterize the 101f epitope, we employed a trypsin digestion of a hrsv f protein-101f mab complex, followed by mass spectrometry analysis of the resulting recovered mab bound peptide. one peptide at m/z 3330 was captured by the 101f mab. sequence assignment was based upon mass and matched with the database from a virtual digest. this peptide was assigned as residues 420-445 [tkctasnknrgiiktfsngcdyvsnk] of the hrsv f protein which spans antigenic site iv,v,vi. to further delineate the epitope, the binding of 101f mab to a series of peptides corresponding to antigenic site iv,v,vi in the hrsv f protein was determined. based on the peptide elisa data, the 101f-binding region could be reduced to 422-436 sequence [ctasnknrgiiktfs] . as demonstrated by the substitution analysis, r429 and k433 significantly contribute to epitope binding, but another positively charged residue, k427 makes a minor contribution to the binding. both, the peptide elisa and proteolytic digestion of the mab-antigen complex approaches identified the same region of hrsv f protein as being critical for the binding of 101f. furthermore, these data confirm the results obtained using complementing genetic approaches using a panel of mutations in recombinantly expressed f protein and selection of antibody escape virus mutants (data not presented). the recently identified uracil-dna specific nuclease (ude) is the first representative of a new family of nucleases. the protein sequence has no detectable homology to other proteins except a group of sequences present in genomes of other pupating insects (vertessy et al, submitted). to analyze the physiological function of this protein, peptide conjugates were prepared to serve as synthetic antigens for the generation of antibodies against isoforms of dutpase, an enzyme inherently involved in preventing the synthesis of uracil-dna [1, 2] . we used poly[lys(seri-dl-alam)] (sak) as a synthetic branched polypeptide [3] or bovine serum albumin (bsa) as a natural macromolecular carrier. peptides were prepared by solid phase method utilizing syro2000 (mulltisyntech gmbh, germany) peptide synthesizer, using fmoc chemistry and dipci/hobt-mediated coupling on rink-amid mbha resin. a c-terminal cys(acm) was added to the native sequences for incorporation of sh group into the peptide. in case of sak choroacetylated polypeptide was conjugated with sh-peptide to form thioether linkage. the maleimidobenzoyil-n-hydroxyszukcinimid (mbs) derivative of bsa was used to introduce the peptide into the macromolecule. antibodies have been developed as diagnostic tools and therapeutics for many different diseases. however, the isolation and preparation of intact specific antibodies is often very tedious or even unfeasible. recent studies have shown that single paratope peptides might be well capable to mimic corresponding antigen ligands [1, 2] , suggesting that paratope peptides from a native antibody might have many advantages, e.g. for molecular vaccine design and targeting. we have developed a new method for identification of paratope-containing peptides by proteolytic affinity-proteome analysis in combination with high resolution fticr-mass spectrometry (fticr-ms) [3] . in the present study we used hen eggwhite lysozyme (hel) and a polyclonal rabbit anti-lysozyme antibody (helpab) as a model system. the direct determination of paratope peptides was obtained by selective binding of a dtt-cleavage mixture of the anti-lysozyme antibody to immobilised hel, followed by proteolytic digestion of the antibody-antigen complex (paratope excision, parexprot). two specific paratope peptides were identified by maldi-fticr-ms, and the corresponding peptide sequences were identified by database search within a 1-2 ppm threshold. additionally, the identified paratope peptides were synthesised and characterised by affinity mass spectrometry, which ascertained their full binding specificity to lysozyme. the propeptide blocks the active site of inactive zymogen of cathepsin d and is cleaved off during maturation. we have designed a set of peptidic fragments derived from the propeptide structure and evaluated their inhibitory potency against mature cathepsin d using kinetic activity assay. the mapping localized two segments in the propeptide involved in the inhibitory interaction with the enzyme core: n-terminus of propeptide plays a major role and the active site anchor plays a minor role according to their respective ki values. in addition, a fragment derived from the mature n-terminus of cathepsin d displayed inhibition, which supports its proposed regulatory role. the mechanism of interaction of both propeptide segments was characterized by the mode of inhibition and by spatial modeling of propeptide in cathepsin d zymogen. using fluorescence polarization measurements, kd in nanomolar range was determined for the n-terminal propeptide segment. the inhibitory potency of the active site anchor segment was modulated by ala38val mutation that was reported to be associated with cathepsin d pathology. . by comparing the resulting low-energy conformations using different sets of atoms, specific conformational features common only to the high/medium affinity compounds were identified. they included the spatial arrangement of the three most important pharmacophoric side chains tyr2, arg4, and nal5 as well as the orientation of the xaa3-arg4 amide bond, which together represent a "minimalistic" 3d pharmacophore model for binding of the cyclopentapeptide antagonists to cxcr4. this model rationalizes the data for the cyclopentapeptides as well as for the peptidomimetic cxcr4 antagonist krh-1636. automated docking of the pharmacophore model to the 3d structure of the tm region of cxcr4 revealed that the pharmacophoric groups of the cyclopentapeptide ligands were involved in favorable interactions with their counterparts in cxcr4. for instance, the hydroxyl group of tyr2 formed a hydrogen bond with lys38, the guanidino group of arg4 formed a salt bridge with glu288, and the backbone carbonyl of xaa3-arg4 formed a hydrogen bond with lys282. this finding gives additional support for the suggested 3d pharmacophore model, and also provides opportunities for rational design of cxcr4 mutants to map potential contacts with peptide ligands. with the successful completion of the human genome project, the next challenge is to assimilate enormous amount of genetic information generated and to assign functions to a large number of proteins encoded. although the dna chip technology to detect the abundance of mrnas has been established, it is known that the abundance of mrnas and proteins does not correlate. thus, protein detection methods for reproducible and quantitative investigation of protein networks are strongly required. we attempted to establish a novel protein detection system based on a fluorescent measurement that does not require labeling of target molecules and preparation of secondary antibodies. we focused on a steric hindrance caused by the interaction between a target protein and a specific capture agent. when a target protein interacts with a specific capture agent immobilized on solid surface, we assumed that a steric hindrance in the vicinity of a capture agent increases. in order to detect the differences in the steric hindrance, we utilized a fluorescent system with the staudinger reaction. this reaction is a chemical ligation between a phosphine and an azide group. these two functionalities are unreactive with protein surfaces under biological conditions. we incorporated an azide group into an immobilized capture agent and investigated the efficiency in the staudinger reaction between the azide and an external triphenyl phosphine derivative. it was found that a target protein bound to the capture agent immobilized onto the solid support interferes with the efficiency in the staudinger reaction. the major histocompatibility complex (mhc) has a crucial role to initiate the immune response via the binding of the peptide fragments (epitopes) of foreign antigens and their presentation to the t-cell receptors (tcr). the co-receptor molecule cd4 enhances the binding between tcr and mhc ii. small molecules that mimic surfaces of mhc-ii may lead to blockage of the autoimmune response and the development of drugs for immunotherapy. hla-dqa1*0501/dqb1*0201 (dq2) and hla-dqa1*0501/dqb1*0301 (dq7) are highly correlated to autoimmune diseases as sjogren syndrome (ss) and systemic lupus erythematosus (sle). the non polymorphic β regions of the modelled hla-dq7, which are exposed to the solvent and may disrupt the interaction of dq7 with cd4+ t lymphocytes were determinated using the getarea program. it was found that the regions 133-140 (arg-asn-asp-gln-glu-glu-thr-thr) and 59-66 (glu-tyr-trp-asn-ser-gln-lys-glu) display the highest solvent accessibility. peptide analogs of these regions were synthesized, by the fmoc/otbu solid phase strategy, purified by rp-hplc and characterized by mass spectrometry esi-ms. the dimeric analogs of the peptides, designed to mimic the superdimeric nature of the immunosuppressory fragments of hla class ii molecules were also synthesized and investigated. conformational studies were performed with cd spectroscopy and biological experiments are in progress. background and aims: aggregates of β-amyloid peptide (aβ) play central role in the etiopathology of alzheimer's disease (ad). short peptides like c. soto's pentapeptide lpffd and lpyfd-amide synthesized in our laboratory are neuroprotective agents against aβ assemblies both in vitro and in vivo. however, the mechanism of their neuroprotective effect has not yet been fully understood. methods: transmission electron microscopy (tem), cd, ft-ir, diffusion ordered nmr spectroscopy, dynamic light scattering, and radioligand binding assays were used. results: all the methods applied showed that the pentapeptides mentioned above do not break the fibrillar structure of aβ, that is these molecules are not real β-sheet breakers (bsb). the pentapeptides bind to aβ fibrils and cause small structural changes by intercalating into the aβ assemblies. fibrils of aβ survive one week treatment with the pentapeptides using them in 2 to 5-time molar excess. conclusion: all the results in our laboratory show that the short peptides have long-term interaction on aβ-assemblies. in the first step they bind tightly to the aβ surface and prevent further interaction of aβ fibrils with the neuronal membranes. after this step the short peptides can be built into the structure of aβ-assemblies with intercalation causing a less ordered β-conformation. proteolytic enzymes (neprilisin, ide) could cleave and hydrolyze aβ peptides after this structural change, therefore the short peptides are good drug candidates for the treatment of ad. cellular processes in normal and pathogenic cell states are regulated by external stimuli via complex networks of catalytic and non-catalytic protein-protein interactions. we have developed methodology for the synthetic variation of peptides and peptidomimetics using polymer reagents including linker reagents enabling polymer-supported cacylations. [1] in combination with the virtual screening of protein subsites, we have demonstrated the application of the novel synthetic methods to inhibitor optimization for various proteases including plasmepsin ii, hiv protease, and sars coronavirus main protease. [2, 3] moreover, multivalent peptide polymers have been developed for the intracellular targeting of proteins. [4] this methodology was now extended to the inhibition of peptide-protein interactions by small molecules. for this purpose, we have composed a library of 20,000 small molecules by algorithmic searching of a database of bioactive molecules with virtually designed substructures (fragments). high throughput assays were developed on the basis of fluorescence and fluorescence polarization detection. despite the scepticism regarding the inhibition of protein-protein interactions with small molecules, efficient hit molecules have been developed for several intracellular targets and were subjected to synthetic variation and cellular follow-up assays. the essential event in platelet adhesion to the blood vessel wall after injury or in thrombosis is the binding to sub-endothelial collagen of plasma von willebrand factor (vwf), a protein which interacts transiently with platelet glycoprotein (gp) ibalpha , slowing circulating platelets to facilitate their firm adhesion through other collagen receptors, e.g. integrin alpha2beta1 and gpvi. to locate thevwf-binding site in collagen iii; we synthesized 57 overlapping triple-helical peptides which comprise the whole native sequence of collagen iii . peptide #23 (gpogpsgprgqogvmgfogpkgnd (o is hydroxyproline)) alone bound vwf, with an affinity comparable to that of native collagen iii. immobilized peptide #23 supported platelet adhesion under static and flow conditions, processes blocked by an antibody which prevents the vwf a3 domain from binding full-length collagen. truncated and alaninesubstituted triple-helical peptides derived from #23 either strongly interacted with both vwf and platelets, or lacked both vwf and platelet binding. thus, we identified the sequence rgqogvmgf as the minimal vwf-binding sequence in collagen iii. the present work completes our understanding of the collagen-vwf interaction, providing information on crucial sequences in collagen that perfectly complements our existing knowledge of the collagen-binding site in vwf and may assist in targeting the collagen-vwf interaction for therapeutic purposes solid phase assay systems such as enzyme-linked immunosorbent assay (elisa), surface plasmon resonance (spr), and overlay gels are used to study processes of protein-protein and protein-peptide interactions. the common principle of all these methods is that they monitor the binding between soluble and surfaceimmobilized molecules. following the use of bovine serum albumin (bsa)-peptide conjugates or isolated synthetic peptides and the above-mentioned solid phase assay systems, we were able to demonstrate that positively charged peptides, which would be expected to repulse each other, can interact with each other. both the elisa and spr methods showed that the binding process reached saturation with kd values ranging between 1 and 14 nm. no interaction was observed between bsa conjugates bearing positively charged peptides and conjugates bearing negatively charged peptides or with pure bsa molecules, strengthening the view that interaction occurs only between positively charged peptides. however, interactions between the same peptides were not observed in solution when was monitored by nuclear magnetic resonance (nmr) or by native gel electrophoresis. thus, it appears that for positively charged molecules to interact one of the binding partners must be immobilized to a surface, a process that may lead to the exposure of otherwise masked groups or atoms. the relevance of our findings for the use of solid phase assay systems to study interactions between biomolecules will be discussed. the hematopoietic progenitor kinase 1 (hpk1), a mammalian hematopoiesis-specific ste20 kinase, contains a cluster of four proline-rich sequences called p1, p2, p3 and p4 located after the kinase domain. these pro-rich regions play an important role in the interactions of this kinase with different adapter proteins. previous studies showed that p1, which contains the canonical pxxpxr motif, and p2 and p4 with the canonical pxxpxk motif interact with the c-terminal sh3 domain of hematopoietic lineage cell-specific protein 1 (hs1) even if with different affinity. hs1 protein shares a high amino acid sequence and structural similarity to cortactin although their functions differ considerably. here we report the results of our investigation on the interaction between the c-terminal sh3 domain of cortactin and the four proline-rich motifs of hpk1. these interactions were analyzed by non-immobilized ligand interaction assay by circular dichroism (nilia-cd). upon peptide addition, the binding was monitored by the cd changes of the trp side-chains of the conjugate gst-sh3cort. the dissociation constants kd were determined analyzing the cd data at 294 nm using a nonlinear regression method. the results demonstrate that gst-sh3cort displays an affinity binding higher than that found with the corresponding hs1 domain and that the four hpk1 pro-rich regions are not equivalent. p2 appears to bind with the highest affinity (kd=0.5 µm), followed by p1 (kd=10 µm) and p4 (kd=33 µm), whilst p3 does not interact at all. the generation of a fibrin clot is mediated by the regulated activation of a series of serine proteases and their cofactors. factor viii in its activated form, fviiia, acts as a cofactor to the serine protease fixa, in the conversion of the zymogen fx to the active enzyme fxa. both fviii and fix are essential for normal coagulation, deficiencies of either are associated with the bleeding diatheses hemophilia a and b, respectively. the role of fviiia is to bind factor ixa, generating the phospholipid-dependent intrinsic factor xase complex. at least two interactive sites have been identified for the enzyme-cofactor interaction. the ser558-gln565 region within the a2 subunit has been shown to be crucial for viiia-ixa interaction. in an attempt to study this interaction, we synthesized a series of peptides of 558-565 loop of the a2 subunit. the syntheses of these peptides were carried out by using spps and fmoc/but methodology. the synthesized compounds were purified by rp-hplc and lyophilized to give fluffy solid, identified by ft-ir, nmr and es-ms spectra. these compounds were tested for inhibitory activity on human platelet aggregation in vitro, by adding common aggregation reagents to citrated platelet rich plasma (prp). the aggregation was determined using a dual channel electronic aggregometer by recording the light transmission. and 120 ci/mmol, respectively. both tritiated aβ peptides were used in cat brain( in vivo) experiments and it was found that the peptide aggregates enter the neurons within 30 min (electronmicroscopic autoradiography). this transport is most probably an endocytotic pathway. aβ aggregates could interact also with cytoplasmic proteins such as 3-phosphoglyceraldehyde dehydrogenase etc. we suppose that aβ assemblies can interact both with membrane receptors (nmda, ampa, ach) and with cytoplasmic proteins triggering neuronal dysfunction and death. background and aims: ww domains are the shortest known protein domains and contain a stable three-stranded b-sheet, which presents the binding site for prolinerich ligands. this interaction is mediated by hydrophobic interactions between aromatic and hydrophobic residues of the domain, and the polyproline core of the ligand. as part of our ongoing efforts aimed at synthetically mimicking conformationally defined protein binding sites (1), we have designed and synthesized linear and cyclic peptides covering the binding site of the ww domain of human yes-associated protein (hyap-ww), whose structure in complex with a proline-rich ligand had been solved by nmr spectroscopy (2) . methods: peptides were synthesized by spps, purified by hplc, and characterized by 2d-nmr spectroscopy, as well as by molecular dynamics calculations. affinities of the peptides to a hyap-ww ligand were determined in direct and competitive binding assays. results and conclusions: a cyclic peptide covering the sequence stretch of hyap-ww that contains its primary contact residues for proline-rich ligands, was found to compete with the domain for binding to a hyap-ww ligand. long-ranging noes identified in the nmr spectra of this peptide indicate a conformation, in which sequentially distant residues are brought into spatial proximity, likely through formation of a beta-sheet. these result demonstrate the feasibility of functional, as well as structural, mimicry of conformationally defined protein binding sites through synthetic peptides. the rockefeller university, new york, ny, usa integrins constitute a family of transmembrane cell surface receptors. they are involved in cell-cell and cell-extracellular matrix interactions. thus, they participate in many physiological and pathophysiological processes and are of crucial importance for the living organism. integrins possess two non-covalently bound subunits, α and β, that jointly participate in ligand binding. these dimeric proteins show very high specificity in recognition of natural ligands. for example, α4β1 integrin recognizes vcam-1 (vascular cell adhesion molecule 1) and fibronectin through binding amino acid motifs tqidspln and ldv, respectively. on the other hand, fibronectin is a classical ligand for α5β1 integrin with the recognition motif rgd. as shown, identification of the integrin ligands occurs through small recognition amino acid sequences (mostly tripeptides). thus, small cyclic peptides possessing a recognition motif in the appropriate three-dimensional conformation are able to interfere with the integrin-ligand interactions and act as inhibitors. the aim of this investigation is the characterisation of small cyclic peptides containing the rgd motif and the determination of the selectivity and specificity of these inhibitors. two new pentapeptides with 3-amino-cyclopropane-1,2-dicarboxylic acid monomethyl ester ((+/-)acc) were synthesized and tested. peptides were characterized in biological assays with living cells (k562 and wm115) and in surface plasmon resonance binding studies. experiments have shown that cyclic peptide cyclo-(arg-gly-asp-(+)acc-val) is a very potent inhibitor (ic50-value in nm range) of interaction between vitronectin and αvβ3 or αvβ5 integrins. when preparing biotin-labelled peptides as ligands for avidin-based assays, it is chemically most expedient to locate the biotin label on the n-terminal group of the peptide. this is done without any regard to how this may affect peptide-target interactions, biotin-avidin binding, and the solubility properties of the resultant peptide. in many instances, the products are poorly soluble, have little biological activity, and poor affinity for avidin. problems can also arise during the synthesis of such nterminally biotinylated peptides due to the poor solubility and reactivity of many of the reagents used for biotin introduction. to overcome these limitations, we have developed an extremely simple method for synthesising peptides c-terminally with biotin. peptides can now be easily prepared by standard solid phase techniques either n-or c-terminally labelled, and screened to determine the optimum presentation for the biotin. in cases studies using protein-protein interaction and kinase assays, peptides c-terminally labelled with biotin gave better sensitivity. y. yang 1 , j. eble 2 , n. sewald 1 many bacterial pathogens bind and enter eukaryotic cells to establish infection. invasin is an outer membrane protein required for efficient uptake of yersinia into m cells. invasin mediates its entry into eukaryotic cells by binding to members of β1 integrin family that lack insertion domains (i domains), such as α3β1,α4β1,α5β1,α6β1, and αvβ1. this type of peptide-protein interaction is an ideal subject for the rational design of inhibitors. the integrin binding motif consists of one loop region with a conservative asp911 residue and two synergistic regions. the aim of this project is to synthesize cyclic peptides based on the invasin binding epitope sdms. this sequence has to be positioned in a β-turn with asp in i+1 position for optimal activity of the peptide. also the arg883 and asp811 residue, which are about 27.29å and 31.54å respectively away from the asp911 residue of the sdms loop in invasin, should be investigated. peptides that mimic these recognition sites have been synthesized and tested as ligands for the integrin peptide-dna cross-linking is a very powerful tool for studying peptide-dna complexes. it transforms non-covalent complexes into covalent complexes, which renders characterization of the adduct by classical techniques (mass spectroscopy, nmr,…) much easier. the aim of our research is to develop a new method for peptide-dna cross-linking involving the incorporation of a furan moiety. the strategy is inspired by the naturally occurring process of oxidative furan ring opening by cytochrome p450. the resulting cis-butene-1,4-dial has been shown to react with amino-and sulfhydryl groups of macromolecules such as proteins and dna. in our research, dna binding peptides are modified with a furan moiety and then chemically oxidized into a reactive enal. this enal can react with dna to form a covalent peptide-dna complex. previous attempts to selectively oxidize furan modified minor groove binding peptides consisting of n-methylpyrrole building blocks failed. we are now applying the same strategy on major groove binding peptides consisting of natural amino acids. currently the oxidation conditions are being optimized so that the furan moiety undergoes selective oxidation. these optimized conditions will be applied to known dna binding peptides, in order to obtain a peptide-dna cross-link. we coupled octanoyl or palmitoyl group to the n-terminus of an analogue of sv40 nuclear localization signal (nls) peptide, sv126-133(ser128) to investigate the effect of fatty acid chain length on the conformation of the lipopeptide-antisense oligodeoxynucleotide (odn) complexes and to establish the optimal peptide/odn molar ratio (rm) for the effective delivery of odn into the cells. the odns used in this study were targeted towards either the green fluorescent protein (gfp) mrna and the junction sequence between ews and fli1 genes. the conformational change of odn at different rm values was followed by circular dichroism (cd), attenuated total reflection-fourier transform infrared (atr-ftir) spectroscopy and atomic force microscopy (afm). the sv40 peptide-mediated odn transfer into nih/3t3 cells was studied by epifluorescence microscopy. the interaction between the hiv-1 regulatory protein rev and rev responsive element (rre) of hiv-1 mrna has emerged in the last decade as an important target in antiviral therapy. the rev-rre interaction is essential for the replication of hiv. the rev protein binds to the rre site located in the env coding region of the full length viral mrna and facilities the export of the rna from the nucleus, while protecting it from the cell's splicing machinery. in the published nmr structure of the rre/rev-derived peptide complex, an -helical segment of rev binding domain recognises a specific region of rre. an approach is described to design a new class of -hairpin peptidomimetic ligands for hiv-1 rev protein, which inhibit its binding to the rre rna. a model -hairpin peptide served as a scaffold to pre-organise side chains into a geometry similar to that seen in a helical peptide. a library of peptidomimetics was prepared by grafting sequences related to the rna recognition element in rev onto a hairpin-inducing d-pro-l-pro template. the electrophoretic mobility shift assay (emsa) revealed that all of the designed peptidomimetics bind to rre and the best examples show affinities (kd) in a nanomolar range. these new ligands show a novel approach to designing rev peptidomimetics, represent interesting leads for the development of more potent hiv rre/rev inhibitors and permit more detailed studies of the mechanism of binding to rna. a. napiorkowska, a. sawula, m. olkowicz, p. mucha, p. rekowski tat (trans-activator of transcription) is the protein which controls the early phase of hiv-1 replication cycle. it is a potent viral trans-activator containing from 86 to 101 amino acid residues which binds to tar rna. the fundamental role of tat is promoting effective elongation of viral mrna (vmrna). binding of tat to tar is mediated by a 9-amino-acid, highly basic arg49-lys-lys-arg52-arg-gln-arg-arg-arg57 sequence of the arm (arginine rich motif); the key role in these interactions is played by arg52. the goal of our research was to investigate the interaction of 27-nucleotide tar rna with synthesized tat peptide analogues using capillary electrophoresis (ce), a powerful analytical technique of biochemical studies. changes in electrophoretic mobility of the tar peak are employed for monitoring tar-tat complex formation. ce experiments were performed using lpa-coated capillary and a physical gel containing buffer. native arm fragment tat(49-57)nh2, its analogues ac-tat(49-57)nh2 and ac-[lys52]tat(49-57)nh2 and analogues substituted in position 52 with alanine-, homoalanine and lysine-derived amino acids containing nucleobases (adenine, guanine, cytosine, uracil, thymine) and nucleosides (adenosine, guanosine, uridine and cytidine) in the side chain were studied. specific interactions and complex formation were observed for both the native arm peptide fragment and selected tat analogues. the research is aimed at improving our understanding of the molecular mechanism of peptide-nucleic acid interaction, as well as evaluating the usefulness of selected nucleobase-containing amino acids as point probes for investigating peptide-rna interactions. interactions between proteins and dna are important to all living organisms. the goal is to investigate the molecular recognition between dna and the transcription factor phob of e. coli on the single molecule level and to identify amino acids required for dna binding. phob is composed of a transactivation domain (amino acids 1-127) and a dna binding domain (amino acids 123-229) that binds to specific dna sequences (pho boxes) containing a tgtca sequence. [1] chemical synthesis of peptide epitopes present in the dna binding domain of phob and isolation of the whole dna binding domain of phob was performed. the protein was purified using intein mediated protein purification. an additional cysteine residue was ligated to the protein using intein mediated ligation reactions and will be used for immobilization and labeling. in single molecule force spectroscopy (afm) experiments it has been shown that both a peptide with a native phob-sequence and the recombinant protein bind to dna. competition experiments were performed to prove specific dna binding. [2] mutated peptides and proteins where strategic amino acids were replaced by alanine have also been examined to reveal the contributions of single residues to molecular recognition. the binding contribution of the proteins is determined by surface plasmon resonance, electrophoretic mobility shift assays and fluorescence correlation spectroscopy. we investigated the biophysical characteristics and the pore formation dynamics of naturally occurring and synthetic peptides forming membrane-spanning channels by using isolated rod outer segments (os) of reptilia and amphibia recorded in the whole-cell configuration. once blocked the two os endogenous conductances (the cgmp channels by light and the retinal exchanger by removing one of the transported ion species from both sides of the membrane, i.e. k+, na+ or ca2+), the os membrane resistance (rm) could be >5 gώ. therefore, any exogenous current can be studied down to the single channel level. macroscopic currents of amplitude of ~300 pa were recorded in symmetric k+ or na+ (>100 mm) and ca2+ (1 mm) from the commercially available alamethicin mixture, the synthetic alamethicin f50/5 (a major component of the natural mixture), and selected analogues applied at 1 µm concentration at -20 mv. once applied and removed the peptide, the current activates and deactivates with a time constant of about 160 ms. the synthetic analogues [glu(ome)7,18,19] and [glu(ome)18,19] produce a current of about 100 pa at 1 µm concentration, and they show a strong activation by hyperpolarization as alamethicin f50/5 itself. clear single channel events were observed when the concentration of all of the alamethicin peptides is reduced to <250 nm.
these results indicate that the three gln residues at positions 7, 18 and 19 of alamethicin f50/5 are not a key factor for pore formation and its conduction properties. in general, the pore assembly and disassembly are very fast and cooperative events. the translocation mechanism of penetratin (rqikiwfqnrrmkwkk) is not clear, but the involvement of cell membrane was supposed. recent studies with phospholipid model membranes have shown that penetratin interacts only with negatively charged liposomes. we aimed to analyse the effect of penetratin on liposomes composed of different phospholipids (dppc/dppg 2:8-8:2) by fluorescence spectroscopy. in the first set of experiments, liposomes labelled with fluorescent markers (dph, ans and tma-dph) were incubated with penetratin and the fluorescence polarisation was determined as a function of the temperature. in the range of 15-200 mol/mol phospholipid/penetratin ratio, no change in the transition temperature was observed indicating that penetratin has no influence on the membrane structure. next, we have analysed the interactions between phospholipids and penetratin through changes in the intrinsic fluorescence of the peptide due to the presence of two w residues in its sequence. comparing the emission spectra corresponding to penetratin in aqueous media or in presence of vesicles one can clearly appreciate a blue shift. this indicates that that tryptophan residues are mainly exposed to a hydrophobic environment. analysis of the main band shows low values of polarization suggesting a free motion of the peptide chain. on the contrary polarization measured for penetratin mixed with liposomes results in higher values. this indicates that hydrophobic residues, like trp, are inserted into the bilayer and their motion is restricted. these data suggest the presence of interation sensed strongly by trp properties. cyclopeptide antibiotic gramicidin s (gs) has antimicrobial activity against gram-positive and gram-negative bacteria and some fungi. but non-specific action of gs and its high lytic potential limits therapeutic application of gs. we attempted to elucidate in which way gs molecule could be modified to lose its haemolytic side effects. gs molecule interacts directly with membrane phospholipids due to electrostatic and hydrophobic interaction. naturally, changes in the state of a lipid bilayer cause changes in the gs molecule binding to a bilayer. we studied the effect of gs on human blood platelets and the effect of platelet membrane state on the gs-induced disaggregation of cells with the help of turbidimetric and microscopy techniques. we modified the membrane state by temperature, osmotic stress, ionizing irradiation, lipid oxidation. depending on concentration gs causes platelet shape change and activation. when added to preliminary aggregated (in response to physiological agonists -thrombin, epinephrine, adp) platelets, gs causes crumble of cells aggregates. the rate and extent of platelet disaggregation under the effect of gs non monotonously depends on temperature (range of 5-40°c) and irradiation dose (up to 200 gy). parameters of the gs interaction with membranes are determined by the mobility of membrane lipids. factors modifying the lipid bilayer change the degree and the speed of the gs interaction with platelet membranes. results obtained permit to use gs for testing the state of membrane lipids and on the other hand allow to suppose ways of gs molecule modifications to achieve its tolerance to blood cells. g. bai 1 , p. gomes 1 , r. seixas 1 , m. hicks 2 , m. prieto 3 , m. bastos 1 eukaryotic antibiotic peptides (eaps) have been widely studied for the past years as an alternative to conventional antibiotics due to emergence of multi-resistant microbial strains, and significant efforts targeting increasingly potent and specific antimicrobial peptides are being made. one interesting approach in peptide antibiotics is based on hybrid sequences derived from natural eaps, with ca ( resistance to conventional antibiotics has stimulated a search for alternative therapeutics for microbial infections, a possible source that has gained much interest in recent years are antimicrobial peptides. antimicrobial peptides target the cell membrane directly, which is a key feature as evolution has shown bacteria have had difficulty in altering their membrane composition and organization to mount a suitable defence against these peptides. a common theory is that peptides that bind strongly exhibit high biological activity, but our real-time quantitative binding studies via surface plasmon resonance (spr) have shown that this correlation does not always hold. as more information on the molecular details of membrane disruption is required, we have used atomic force microscopy (afm) to visualise peptide insertion and changes in membrane morphology by a range of antimicrobial peptides in situ. interaction studies were performed with a series of phospholipid mixtures that mimic either mammalian cells (high in phosphatidylcholine and cholesterol) or microbial cells (high in phosphatidylethanolamine and phosphatidylglycerol). the present study may assist in the design of new specific antimicrobial peptides with high antimicrobial activity and low host toxicity. proportions of popc and popg as models. very high molar ratio partition constants ((18.9+-1.3)x10^3 and (43.5+-8.7)x10^3) were obtained for the bacterial models (popg:popc 4:1 and 2:1, respectively), these being about one order of magnitude greater than the partition constants obtained for the less anionic mammalian model systems ((3.7+-0.4)x10^3 for the 100% popc system). at low lipid:peptide ratios there were significant deviations from the usual hyperbolic-like partition behavior of peptide vesicle titration curves, especially in the case of the most anionic systems. membrane saturation was shown to be related to such observations and mathematical models were derived to further characterize the peptide-lipid interaction under these conditions. the calculated peptide-to-lipid saturation proportions, together with the determined partition constants, suggest that the minimal inhibitory concentrations of omiganan pentahydrochloride could represent the conditions required for bacterial membrane saturation to occur. the hemolytic pore-forming toxin sticholysin ii (stii) produced by the sea anemone stichodactyla heliantus belongs to the actinoporin protein family. the n-terminal domain of these proteins is required for interaction with membranes. to investigate the role of stii´s n-terminal domain in membrane binding and in the molecular mechanism of hemolysis, peptides corresponding to residues 1 to 35, or shorter fragments from this region, were synthesized. in some peptides leu was replaced by trp. all peptides exhibited hemolytic activity, albeit to a lesser extent than the whole protein. moreover, peptides lacking the 1-14 hydrophobic stretch were less active. the longer peptides were also able to permeabilize phospholipid vesicles. conformational studies were performed in aqueous solution and in membranemimicking environments. cd spectra showed that, while the shorter, more hydrophilic peptides, displayed a random conformation, the longer peptides underwent aggregation with increasing concentration, ph, and ionic strength. in the presence of trifluoroethanol and upon binding to detergent micelles and phospholipid bilayers, the peptides showed a propensity to acquire -helical conformation, as expected for the sequence comprising residues 14 to 26. fluorescence spectra demonstrated that the first residues of stii´s n-terminus penetrate more deeply into the bilayer, whereas residues 14-26 are located more superficially. this is in agreement with the predicted amphipathic nature of the helix formed by these residues and corroborates the existing hypotheses for the role of the n-terminal domain in the process of membrane insertion and pore formation. among a great number of antibacterial peptides a group of trp-rich peptides is of special interest. taking into consideration, that in most of proteins tryptophan is not frequently occurring amino acid, the biological meaning of a high content of tryptophan in structure of these antimicrobial peptides is particularly interesting. in the present study we carried out the investigation of antimicrobial and hemolytic activities of selected trp-rich peptides and their action on microbial membrane: ilpwkwpwwpwrr-nh2 indolicidin (i) pitwpwkwwkgg-nh2 3b3 (ii) plswffprtwgkr-nh2 gsp-1a (iii) fpvtwrwwkwwkg-nh2 puroindoline (iv) vrrfpwwwpflrr-nh2 tritrypticin (v). sunflower trypsin inhibitor sfti-1 is the smallest and the most potent known peptidic trypsin inhibitor from the bowman-birk class of proteins [1] . this head-to-tailcyclized 14-amino-acid peptide contains one disulfide bridge and a lysine residue (lys5) present in the p1 position, which is responsible for inhibitor specificity.as was reported by us and other groups, sfti-1 analogues with one cycle only retain trypsin inhibitory activity. very recently we have shown [2] that introduction of nsubstituted glycine residues mimicking lys and phe (denoted as nlys and nphe) in the p1 position of monocyclic sfti-1 with disulfide bridge yielded potent trypsin and chymotrypsin inhibitors, respectively. in this novel class of proteinase inhibitors contains completely proteolytic resistant p1-p1' reactive site. in the present communication we report chemical synthesis and determination of trypsin and chymotrypsin inhibitory activity of a series of ten sfti-1 analogues modified in the p1 position by these peptoid monomers (nlys and nphe). each of the synthesized peptomeric (peptide-peptoid hybrid polymer) sfti-1 analogues contains one of the following cycles: head-to-tail, disulfide bridge formed by cys, by pen and by cys/pen residues. the impact of the different cycles introduced into sfti-1 structure on proteinase inhibitory activity will be discussed. s-protein contains a proteolytic processing site and two interacting heptad repeat regions denoted as hr-n and hr-c. following processing of s-protein mediated by host cellular protease/s, the c-terminal s2-fragment fuse with host cell membranes via its hr-n and hr-c domains that form coiled coil 6-helix bundle (trimeric of dimers)-crucial for its receptor-mediated viral fusion. our objective in this work is to study the proteolytic site using model peptides and also to examine the interaction of hr-n and hr-c domains using fluorescence microscopy and other techniques. thus we synthesized an intramolecularly quenched fluorogenic peptide containing the proposed cleavage site [abz-eqdrntr761 evfatyx, abz=2-amino benzoic acid and tyx=3-nitro tyrosine] and showed by kinetic measurements that this cleavage is mediated most efficiently by furin, followed pc5 and pc7. other potential substrates were also tested and compared. above cleavage can be blocked by specific-pc-inhibitors in a dose-dependent manner. in addition using fluorescent-labeled peptides derived from hr-n and hr-c domains, circular dichroism spectra and surface assisted laser desorption mass spectral interest has grown to develop specific and potent inhibitors of this enzyme. our objectives in this study are to generate soluble recombinant human (h)ski-1 enzyme, design potent inhibitors and study its 3dmodel structure. we have successfully expressed hski-1 enzyme lacking its transmembrane domain in hek-293 cells and purified the enzyme via chromatography. in addition we developed ski-1 inhibitors by using pseudo-and multi-branch peptide approaches. in first approach we inserted dipeptide isosteres amino oxy acetic acid (aoaa) or 8-amino 3, 6 dioxa octanoic acid (adoa) at scissile p1-p1' position ((r175 l) of hski-1. a typical example is 167gryssrrl(adoa)aip179. other dipeptide isosters were also incorporated at the cleavage site of either ski-1 prodomain or lassa virus glycoprotein. in second approach we prepared 2 and 4-branch peptides containing hski-1128-137 segment. these peptides inhibit ski-1 in competitive manners with varying degrees ranging from low m to high nm ic50. circular dichroism spectra indicated strong interactions of inhibitors with ski-1 consistent with observed inhibition profile. a 3d-model structure of catalytic domain of ski-1 indicated a broad catalytic pocket cysteine proteases are of great importance in biochemical processes and these enzymes are used in biotechnology, food industry and agriculture. in this connection synthesis of high selectivity and high specificity substrates for cysteine proteases is of importance. enzymatic synthesis of peptides is a good tool for obtaining different biologically active peptides. immobilized serine proteases, subtilisin carlsberg and α-chymotrypsin immobilized on poly(vinyl alcohol) cryogel (pvacryogel), proved to be a convenient biocatalyst for such kind of syntheses. the high specific chromogenic substrate for cysteine proteases assay glp-phe-ala-pna was obtained with high product yields (up to 88% in 24 h) using subtilisin and chymotrypsin immobilized on pva-cryogel. the reaction was carried out according to the following scheme: glp -the residue of pyroglutamic acid, pna -p-nitroanilide. the influence of initial concentrations of components, the reaction mixture composition, the biocatalyst content and time on product yield was studied. it was shown that the optimal conditions are: dimethylformamide-acetonitrile mixture 20:80 (v/v), initial concentrations -85 mm, and enzyme-to-substrate ratio -1:3900. this approach was used in order to synthesize analogous substrates, containing different fluorogenic and chromogenic groups as well as other amino acids in p1position. the obtained substrates were tested for the papain assay. peptidyl-a-ketoaldehydes 3 represent attractive lead compounds and intermediates in the development of potent protease inhibitors due to their structural similarity with peptide aldehydes, previously known to be excellent inhibitors of serine-and cysteine protease. recently, we demonstrated the application of polymer cyano methylene-and carboxylato methylene phosphoranes in the assembly of a-hydroxy-b-amino esters (norstatines), a,b-diketoesters, and a,b-unsaturated ketones. [1, 2, 3] we now present a further development of our reagent linker 2 approach employing peptidyl-a-ketoaldehydes 3 and diamino propanoles 4. carboxylato methylen phosphoranes 1 derived from bromo acetic esters which are readly acylated without racemization, play the key role in our synthetic concept. herein we show the oxidative cleavage to peptidyl-a-ketoaldehydes 3 using dimethyldioxirane (dmd) in acetone as oxidant, after saponification and decarboxylation on the solid support. diamino propanoles 4 were furnished via the reductive amination of resin-bound peptides. over the past few years nuclear magnetic resonance has emerged as a powerful means for lead molecular identification and optimization.on the other hand, the 19f nmr has been used succesfully in several structural studies, protein folding studies and for the identification of active compounds, using a very similar methodology that the one used in the present work. the methodology required the labeling of the substrate with a cf3 moiety. the enzymatic reaction is performed with the cf3 substrate and quenched, using an enzyme inhibitor. 19f nmr is then used to monitor the evolution of both substrate and product. only two peaks are observed, the starting substrate and the cleaved substrate. this nmr method has some advantages: fluorine nmr is very sensitive, 0,83 times that of the proton. there are no spectral interference from protonated solvents, buffers or detergents typically present in the enzymatic reactions.the 19f isotropic chemical shift is extremely sensitive to small structural perturbations resulting in different chemical shift for the signals of the substrate and product. isotopic labeling of the protein is not required. as a model, caspase-8, which play a critical role in the initiation of apoptosis process5 and hiv-1 protease were chosen. two different kind of libraries were screened: one based on natural products from plant and animal extracts used in tradicional chinese medicine and a second one corresponding of a synthetic library with two sublibraries of 160 and 144 compounds.with this methodology it has been possible to identify some compounds with very promising inhibitory properties. background and aims: human kallikrein 2 (hk2), a prostate specific serine protease, regulates the activity of several factors that may participate in proteolytic cascades promoting tumor growth and metastasis. thus, inhibition of its enzymatic activity is a potential way of preventing growth and metastasis of prostate cancer. moreover, specific ligands for hk2 have potential use for targeting and in vivo imaging of prostate cancer and for development of novel assays. methods: to find peptide ligands we panned several phage display peptide libraries against active recombinant hk2 captured by a monoclonal antibody exposing the active site of the enzyme. alanine scanning and amino acid deletion analyses were performed to elucidate the motifs required for hk2 inhibition. results: from libraries expressing 10 and 11 amino acid long linear peptides we isolated six different hk2-binding peptides. three of these peptides are specific inhibitors of the enzymatic activity of hk2. amino acid substitution and deletion studies indicated that motifs of 6 amino acids are necessary for the inhibitory activity. conclusions: we have developed specific hk2 inhibitors by phage display technology. these novel hk2 specific peptides are potentially useful for treatment and targeting of prostate cancer. peptidylarginine deiminase iv (padiv) catalyzes the citrullination of arg residues in various peptides and proteins, such as histone, resulting in the production of citrullinated proteins in granulocytes [1, 2] . the citrullination mechanism of histone subunits and its functional effects in cells are not well known yet in detail. recently, it has been reported that the protein deimination/citrullination by pad iv plays a role in rheumatoid arthritis [3] . this implicates that the citrullination of histone may be related to rheumatoid arthritis. in order to further study the citrullination mechanism of histone, we explored the citrullination sites of histone h2a and h3 by pad iv using a series of synthetic peptides. recently, hagiwara et. al. reported that pad iv only citrullinates the arg3 of histone h2a as well as the arg3 in histone h4 [4, 5] . in order to investigate the citrullination mechanism, the n-terminal peptides of histone h2a and h3 were chemically synthesized and examined the citullination by pad iv. the n-terminal acetylation effect of the n-terminal synthetic peptide was also estimated on the citrullination by padiv. the velocity of each arg residues in the n-terminal peptides were estimated in vitro. the results indicated that padiv recognizes the specific arg residues in the synthetic peptide, and that the n-terminal acetylation of the histone peptides dramatically affects on the substrate recognition of padiv. in addition, the cd spectra of the n-terminal peptides were measured to elucidate the structural specificity for the recognition of pad iv. background and aims. prolyl oligopeptidase (pop) is a serine peptidase that cleaves oligopeptides after prolyl residues. it has been associated with cognitive disorders. pop inhibitors have been shown to enhance cognition in monkeys (1) and to improve performance in verbal memory tests in humans (2) . in the present study, the p2 l-prolyl residue of pop inhibitors was replaced by two l-proline mimetics, the 5-t-butyl-l-prolyl group and the (r)-cyclopent-2-enecarbonyl group. the effect of the mimetics on in vitro potency, lipophilicity and binding kinetics were studied. methods. the l-proline mimetics were synthesized according to the published procedures (3, 4) with minor modifications. the ic50 and ki values and the binding kinetics were determined for porcine pop. the log p values were determined with the shake-flask method. results. the replacement of the p2 l-prolyl residue by the l-proline mimetics gave compounds which were equipotent with their parent structures. both l-proline mimetics increased lipophilicity but the effect of the 5-t-butyl-l-prolyl group was more pronounced. while the 5-t-butyl-l-prolyl group increased the dissociation half-life of the enzymeinhibitor complex, the (r)-cyclopent-2-enecarbonyl group decreased it. conclusions. both l-proline mimetics perfectly mimicked l-proline at the p2 position of pop inhibitors. these mimetics can be used to modify the lipophilicity and the binding kinetics of pop inhibitors. the proteasome is an essential multicatalytic protease of the ubiquitin proteasome pathway. as a prime executor of regulated proteolysis, the proteasome controls almost all aspects of cell metabolism from signal transduction to cell cycle and differentiation. pharmacological intervention into proteasome activity leads to cell apoptosis. this observation was applied to successfully treat multiple myeloma, since the cancer cells exhibit substantially higher sensitivity to competitive inhibition of proteasome than normal cells. however, the complete shutting down of the proteasome catalyzed proteolysis leads to serious side effects resulting from the disruption of proteolytic homeostasis even in noncancerous cells. here, we show an alternative approach to control the proteasome activity using peptide based noncompetitive regulators. the cathelicidins derived peptides rich in proline and arginine (pr) residues have been found to affect activity of all the proteasome complexes both in vivo and in vitro, likely by binding to the face of the enzyme. mechanism and structural constrains of the pr peptides dictating their influence on the proteasome remain elusive. our results indicate that there are three sequence related properties of the pr peptides controlling their effectiveness as proteasome regulators: length of the peptide, distribution of a set of positive charges at the peptide n-terminus, and positioning of proline residues. far uv cd spectroscopy demonstrates that these properties also correlate with the structure of pr peptides. in particular, it seems that structural propensity of the pr peptides to form beta-turns are required to bind to proteasome as regulatory competent molecules. our work is focused on the search of selective, low-molecular cathepsin b peptide inhibitors acylated with the (e)-3-(benzylsulphonyl)acroyl group (bsa). the double bond, embedded in the bsa moiety is activated by two electron-withdrawing groups and may be a good target for the michael-type addition of the catalytically active -sh group. three series of peptide derivatives possessing general structures: bsa-phe-asn(r)-oh, bsa-ile-x(oh)-n(ch3)2 and bsa-x-pro-oh were synthesized in solution and characterized by enzyme kinetic studies against papain, cathepsins b and k. it should be noted that all the investigated compounds were competitive and reversible inhibitors of the enzymes examined. using 2d 1h nmr (tocsy, cosy, roesy) and 13c nmr spectroscopy along with theoretical calculations (analyse program) we determined the conformational properties of two most potent and selective cathepsin b inhibitors. this work was supported by grant ds/8350-5-0131-6. background and aims: we have developed peptides inhibiting human kallikrein-2 (hk2) activity. as hk2 is overexpressed in prostate cancer tissue, these peptides are potentially useful for treatment and diagnosis of prostate cancer. two of the potential physiological substrates for hk2 are proform of prostate specific antigen (propsa) and insulin-like growth factor-binding protein-3 (igfbp-3). both of these might participate in the regulation of prostate cancer growth: igfbp-3 by inhibiting igf-dependent tumor growth and psa by degrading extracellular matrix. we aimed to study whether our hk2-inhibiting peptides inhibit also hk2 activity towards natural protein substrates, i.e. activation of propsa and degradation of igfbp-3. methods: the effect of the peptides on the activation of propsa by hk2 was studied by preincubating the peptides with hk2, followed by addition of psa and specific psa substrate. igfbp-3 degradation was studied by two specific immunoassays, one detecting only native igfbp-3, while the other one also detected proteolytically cleaved forms of the protein. results: hk2-inhibiting peptides were found to inhibit propsa activation and igfbp-3 degradation by hk2 in a dose dependent fashion. conclusions: we have developed new peptides inhibiting hk2 activity towards natural substrates, like propsa and igfbp-3. the peptides might be useful for treatment of prostate cancer and other diseases associated with increased hk2 activity. from the seeds of garden four-o'clock and spinach we isolated two serine proteinase inhibitors (mjti i -mirabilis jalapa trypsin inhibitor and soti i -spinacia oleracea trypsin inhibitor), which are probably representatives of a new family of inhibitors. the purification procedures of these inhibitors included affinity chromatography on immobilized methylchymotrypsin in a presence of 5 m nacl, ion exchange chromatography and/or preparative electrophoresis and finally rp-hplc on c18 column. their primary structures (fig. 1 ) differ from those of known trypsin inhibitors, but showed significant similarity to one another, as well as to the antimicrobial peptides isolated from the seeds of mirabilis jalapa (mj-amp1, mj-amp2), mesembryanthemum crystallinum (amp1) and phytolacca americana (amp-2 and pafs-s) and from hemolymph of acrocinus longimanus (alo-1, 2 and 3). the equilibrium association constants (ka) of mjti i and soti i with bovine -trypsin were found to be about 107-109 m-1. mjti i and soti i have been synthesized using solid-phase method. the synthesized inhibitors and inhibitors isolated from plants have similar properties. the disulfide bridge pattern in both inhibitors was established after digestion with thermolysine, followed by the maldi-tof: cys1-cys-4, cys2-cys5 and cys3-cys6. s. cosgrove, l. rogers, c. hewage, j.p. malthouse aspartyl proteases are required for the multiplication of the aids virus and for producing the amyloid protein which causes alzheimer's disease. hiv protease inhibitors have been highly effective in treating aids patients and it is hoped that potent inhibitors of the beta secretases will also prove effective in treating alzheimer's disease. therefore inhibitors of the aspartyl proteases have great therapeutic potential. we have shown that the peptide glyoxals are potent inhibitors of the thiol protease papain and of the serine proteases subtilisin and chymotrypsin. using 13c-nmr we have been able to show that glyoxal inhibitors react reversibly with an active site nucleophile in these enzymes to form a tetrahedral adduct which is tightly bound by the enzyme. in the present work we synthesise 13c-enriched peptide glyoxals, we assess their inhibitor potency, and use 13c-nmr to examine how the inhibitors interact with the aspartyl protease pepsin. z-ala-ala-[2-13c]phe-glyoxal was synthesised from [1-13c]phenylalanine which was converted to its methyl ester. this was then coupled with z-ala-ala to give z-ala-ala-[2-13c]phe-ome which was hydrolysed to the free acid. this was converted to the diazoketone and transformed into z-ala-ala-[2-13c]phe-glyoxal using dimethyldioxirane. nmr spectra at 11.75 t were recorded with a bruker avance drx 500 standard-bore spectrometer. we show that peptide glyoxal inhibitors can be potent inhibitors of pepsin and that pepsin only binds one of the four glyoxal forms (one non-hydrated, one fully hydrated and two partially hydrated forms). alzheimer`s disease (ad) is the most common cause of dementia in older people. a major factor in the pathogenesis of ad is the cerebral deposition of amyloid fibrils, consisting of amyloid β peptides (aβ), as senile plaque. the 40-to 42 amino acid long aβ is generated by the proteolysis of β-amyloid precursor protein (app) by β-and γ-secretases. since bace1, a unique member of the pepsin family of aspartyl proteases initiates the pathogenic processing of app by cleaving at the n-terminus it is a molecular target for therapeutic intervention in ad proteolytic activity was found to occur, to a variable degree, in digestive organs of all studied organisms over the entire ph range. the common feature was the existence of two activity peaks, in the acid (ph 2.5 -3.5) and alkaline (ph 7.5 -8.5) zones, as well as a similar protease set containing e and d cathepsins, a trypsin-like enzyme, elastase, and collagenolytic proteases. proteolytic activity in the hepatopancreas of crab and sea star was found to be an order higher than in other study objects. high protease activity in crab hepatopancreas is an evolutionary mechanism compensating for a poor differentiation of digestive system, low substrate specificity of enzymes, and cold environment. trypsin activity in digestive organs of invertebrates suggests that a trypsin-like enzyme is a genetically old one, an evolutionary origin of all serine proteases. a difference of kind between vertebrates and invertebrates is that the latter have cathepsine activity (absent in vertebrates) and no pepsin activity. it is of interest to develop enzyme inhibitors containing a light activated switch that can be used to control binding and inactivation of an enzyme. several inhibitors containing the azobenzene photoswitch group have previously been developed and have shown changes in activity of around two times on photoswitching. this study aimed to improve this switching by more extensive derivatisation of azobenzene to closer resemble the peptide substrates of proteases. a series of peptidomimetics containing the azobenzene photoswitch group were synthesized and assayed against the protease alpha-chymotrypsin. these compounds contained azobenzene, linked to a known chymotrypsin inhibitory group (either a trifluoromethylketone or boronate ester), and otherwise designed to be peptide-like. in some cases both ends of the azobenzene moiety were derivatized in order to increase the impact of photoswitching on the shape of the compound and thus its enzyme binding strength. assays showed that most compounds were reversible inhibitors of chymotrypsin, with low micromolar inhibition constants (ki or ic50). up to four times increase in enzyme inhibition on light activated switching of the azobenzene group conformation was obtained. a number of peptidyl derivatives structurally based upon the inhibitory sites of cystatins has been synthesized. these compounds are prone to proteolytic degradation, are rapidly excreted and poorly bioavailable. the majority of this problems might be overcome by use of peptidomimetics with structures resembling those of previously synthesized peptidyl derivatives. among the peptidomimetics are azapeptides, in which alpha-ch group of amino-acid residue is replaced by a nitrogen atom. the azapeptides have recently been demonstrated as potent and selective inhibitors of cathepsins b and k. it was shown that azapeptide inhibitors bind along the active site cleft of cathepsin b in a bent conformation. this bent structure is likely to result from the mobility of the bonds in the vicinity of the inserted azaamino acid residue as well as from the interaction with enzyme. in our present work we have studied the peptide of a sequence: z-arg-leu-arg-gly-ile-val-ome, which is characterized by one major and three minor conformations. the replacement of alpha-ch group in the gly residue of peptide chain of z-arg-leu-arg-gly-ile-val-ome by the nitrogen atom likely results in rigid conformation. our aim was a comparison of structure of the parent peptide z-arg-leu-arg-gly-ile-val-ome and a selective cathepsin b inhibitor z-arg-leu-arg-agly-ile-val-ome by using 1h-nmr. severe acute respiratory syndrome corona virus associated main protease (sars cov mpro protease), alternatively known as chymotrypsin-like protease (3clpro), is a mediator of virus infection cyclus and from there a therapeutic target. a peptide aldehyde library targeting the sars corona virus main protease (sars-cov mpro, alternatively known as 3clpro) was designed on the basis of three different reported binding modes and supported by virtual screening. a set of 25 peptide aldehydes were prepared by a newly developed methodology and investigated in an inhibition assay against sars-cov mpro. [1] protected amino acid aldehydes furnished by the racemization-free oxidation of amino alcohols with dess-martin periodinane were immobilized on threonyl resins as oxazolidines. following boc-protection of the ring nitrogen yielding the n-protected oxazolidine linker, peptide synthesis was performed efficiently on this resin releasing deprotected products under mild hydrolysis conditions. the library was tested in a new fluorimetric enzyme assay for sars cov mpro. via immobilization of the fluorophor, 2-(7-amino-4-methyl-3-coumarinyl)-acetic acid, the substrate actsavlq-amca was prepared, surprisingly displaying a higher affinity than the native substrate. several potent inhibitors were found with ic50 values in the low micromolar range. interestingly, the most potent inhibitors seem to bind sars-cov mpro in a non-canonical binding mode. currently, the initial screen is extended towards the discovery of small molecule inhibitors of sars corona virus main protease. literature: a method of bromelain cleavage of surface glycoprotein hemagglutinin (ha) from the influenza a virions was initially employed for ha ectodomains crystallographic study [1] . the remaining spikeless subviral particles were used by us earlier for ha2 c-terminal fragment extraction and mass spectrometric (ms) investigation [2] . now sds-page analysis of the subviral particle preparations revealed several additional bands in a range of 9-23 kda together with major viral proteins comparing to intact virions (figure, m1matrix protein, f1-f5-m1 protein fragments, np-nucleoprotein). maldi-tof ms analysis of the in-gel trypsin hydrolyzates has shown that the additional bands are fragments of м1 protein. this was confirmed by n-terminal sequencing of the protein fragments electroblotted from the bands. concentration of sh-reducing reagent in bromelain digestion reaction influenced on the m1 fragment bands intensity. we conclude that due to membrane destabilization during ha spikes removing, m1 protein localized under viral membrane inside intact virions becomes accessible to limited proteolysis by bromelain. [ dipeptidyl peptidases (dpp's) sequentially release dipeptides from polypeptides. among those enzymes, dppiv, fapα, dpp8, dpp9 and dppii cause the release of n-terminal dipeptides containing proline or alanine at the penultimate position. they are all members of clan sc, a group of serine proteases that contains proline-specific peptidases. dipeptidyl-peptidase iv (dppiv) is the best studied member of this group of enzymes and has become a validated target for the treatment of type 2 diabetes over the last years. the development of inhibitors for the related enzymes (i.a. dppii) has only started recently. this poster presents selected products synthesised to further elaborate the structure-activity relationship for dpp ii inhibitors with a 2,4-diaminobutyrylpiperidine basic structure. this class of compounds was described earlier by our group as the hitherto most potent and selective inhibitors of dpp ii. starting from n4-p-chlorobenzyl-substituted uamc00039, our lead compound, two types of modifications were proposed: • the synthesis of n4-(di)alkyl-and arylalkyl analogues; • the synthesis of 3-methyl analogues. in our previous study, we reported potent and small-sized bace1 inhibitors containing phenylnorstatine [(2r,3s)-3-amino-2-hydroxy-4-phenylbutyric acid; pns] at p1 position as a transition-state mimic. in developing more active compounds, we focused our attempts on the p1 position, where we replaced the pns by its thioderivative. herein, we present the synthesis of a novel phenylthionorstatine [(2r,3r)-3-amino-2-hydroxy-4-(phenylthio)butyric acid; ptns] as a p1 moiety with hydroxymethylcarbonyl (hmc) isostere, and then an application to the bace1 inhibitors design. we have synthesized ptns starting from readily available n-benzyloxycarbonyl-serine and after multistep reaction (including weinreb amide formation, thiophenyl group introduction, through cyanohydrin derivative the transformation into the 2-hydroxy ester and then acid). purification was done by column chromatography and rp-hplc. peptides were synthesized by the fmoc based solid phase method and characterized by maldi-tof ms. the peptide inhibitors were adopted to enzyme assay using a recombinant human bace1 and a fluorescence-quenching substrate. bace1 inhibitory activity was determined based on the decrease% of the cleaved substrate by the enzyme.we have synthesized ptns and then the (2r,3r)-enantiomer was applied to spps (solid phase peptide synthesis). we synthesized octa-and pentapeptide-type inhibitors of bace1 containing pns or ptns at the p1 position. these compounds were enzymatically tested and showed high bace1 inhibitory activity. a novel derivative of pns, ptns, was synthesized, and evaluated in comparison to corresponding pns. the inhibitors with ptns exhibited a slightly higher inhibitory activity against bace1 comparing to those with pns. this study suggests possibilities of the application of ptns to design other aspartyl proteases inhibitors. the αν β3 integrin receptor plays an important role in human metastasis and tumor-induced angiogenesis, mainly by interacting with matrix proteins through recognition of an arg-gly-asp (rgd) motif. inhibition of the αν β3 integrins with a cyclic rgd peptide impairs angiogenesis, growth and metastasis of solid tumours in vivo. the aim of this study was to investigate the effects of replacement of amino acids by aza-β3-amino acid analogs in cyclic rgdpeptides as αν β3 -integrin antagonist on angiogenesis, microcirculation, growth and metastasis formation of a solid tumour in vivo. the selectivity profile of these antiadhesive cyclopeptide is rationalized by a special presentation of the pharmacophoric groups. thr rgd motif resides in position i to i+2 of a regular γ-turn. we synthetized linear and cyclic aza-β3 rgd-peptide with the purpose to examine the effect on the conformation and the activity. are aza-β3 amino acids γ-turn mimetics? the preferred conformations were determined by nmr. prostaglandins are involved in a large number of biological activities mediated by their g-protein coupled receptors (gpcrs). the prostaglandins pgf2 alpha receptors are found specifically in uterine muscle, where they initiate parturition and labor. the pgf2 alpha receptor plays a key role in preterm labor, for which medical and social costs are estimated at $ 9 billion per year in the usa (the highest per patient cost of any disorder). peptide mimics have been developed in our laboratory (1, 2) , that serve as allosteric antagonists of the pgf2 alpha receptor. the importance of the turn geometry of the central residue in these peptide mimics has been investigated using enantiomeric indolizidin-2-one beta-turn mimics which can respectively induce type ii and ii' geometry. our presentation will discuss the synthesis and biology of these novel allosteric modulators of prostaglandin pgf2 alpha receptor activity. it was shown that luteinising hormone -releasing hormone (lhrh) receptors are overexpressed in the most of adenocarcinoma cells in contrast to their low content in normal tissues. these data create the basis for lhrh analogues application in therapy of breast, ovary, prostate, lung, intestine, liver and kidney cancers. both agonists and antagonists utility for the targeting of cytotoxic moiety to the tumor cells is well documented. however, the number of lhrh analogues possessed their own cytotoxic activity is still very limited. we nicotianamine (na) that was first isolated from the leaves of nicotiana tabacum l [1] , is known as a key biosynthetic precursor of phytosiderophores. various studies have proved that nicotianamine plays a significant role in plants as an iron, nickel, zinc ... transporter [2] . the aim of our study was to synthesize unnatural analogues of na via peptide intermediates, to investigate the mechanisms of metal transport and accumulation within the plant. we found that the strategy developed for na synthesis could not be applied when the azetidine ring was changed for pyrrolidine ring and we investigated a new route to synthesize such analogue. these synthetic pathways will be discussed. the primary physiological roles of arginine vasopressin (avp), [cycle1-6 (h-cys1-tyr2-phe3-gln4-asn5-cys6-pro7-arg8-gly9-nh2)], involve vasoconstriction of vascular smooth muscles, via v1a receptor, and antidiuretic action in kidney (blood osmolality regulation) via v2 receptor. binding of avp to the v1a receptor subtype also stimulates glycogenolysis in the liver and promotes platelet aggregation. in addition, activation of the v1b (also known as v3) receptor causes adrenocorticotropic hormone release from the anterior pituitary. v1b receptors are also present in the brain where avp functions as a neurotransmitter. in the recent years by the salivary glands of several bloodsucking animals like, teaks, leeches, vampire bats and so forth are isolated plenty of proteins and peptides with different molecular weight and well established anticoagulant activity. many of the strongest anticoagulants isolated by bloodsucking animals are found in the extract of salivary glands of different kinds of leeches. such leech is the haementeria officinalis, from which is isolated the most active inhibitor of factor xa -ats. in order to study the role of some amino acids in the process of interaction among peptides mimetics and the active site of serine proteinases, some fragment analogues of ats's active site by replacement of some amino acids with the other with similar structure or with unnatural amino acids were synthesized. in the present work the synthesis and the anticoagulant activity according to the aptt and ic50 of the newly synthesized peptides and structure-activity relationship will be discussed. rational design of peptides is a challenge which would benefit from a better knowledge of their rules of sequence-structure-function relationships. peptide structures can be approached by spectroscopy and nmr techniques but data from these approaches too frequently diverge. structures can also be calculated in silico from primary sequence information using three algorithms: pepstr, robetta and peplook. the most recent algorithm, peplook introduces indexes for evaluating structural polymorphism and stability. the method uses a de novo search of energy minima by an iterative boltzmann-stochastic procedure and using a combination of 64 phi/psi couples derived from the structural alphabet for protein structures proposed by etchebest et al. for peptides with converging experimental data, calculated structures from peplook and, to a lesser extent from pepstr are close to nmr models. the peplook index for polymorphism is low and the index for stability points out possible binding sites. for peptides with divergent experimental data, calculated and nmr structures can be similar or, can be different. these differences are apparently due to polymorphism and to different conditions of structure assays and calculations. the peplook index for polymorphism maps the fragments encoding disorder and the mean force potential score indicates which residues will be most available for interactions with partners. this should provide new means for the rational design of peptides. several diseases like cancer metastasis, rheumatoid arthritis and chronic lymphocytic b-cell leukemia are linked to the interaction of the cxcr4 chemokine receptor to its natural ligand, the 68 amino acid protein stromal cell-derived factor-1α (sdf-1α). [1] one strategy for the treatment of these diseases could be to block the interaction between cxcr4 and sdf-1α with small cxcr4 antagonists. furthermore, radiolabeling of suitable compounds with appropriate radioisotopes could provide agents for imaging of cxcr4 expression in vivo via pet. previous studies by fujii et al. on cxcr4 antagonists led to a high affinity cyclic pentapeptide with the sequence cyclo[gly-d-tyr-arg-arg-nal]. [2] to further improve this structure, different approaches have been chosen with respect to metabolic stability, bioavailability, conformational rigidity and chemical versatility for radiolabeling. first, an n-methyl scan of the backbone amides was performed to influence conformational freedom and to increase metabolic stability and bioavailability. n-methylation of arginine residues yielded peptides with moderate affinity (ic50-values: 23nm (n-me)arg3 and 31nm (n-me)arg4, resp.) whereas n-methylation of other amino acids significantly decreased the affinity (ic50>100nm). by substitution of arg3 by ornithine, the affinity was mostly retained. [3] the amino group of orn can be alkylated or acylated via radiolabeled groups containing short lived isotopes. moreover, the bioavailability should be improved as the high basicity of the two guanidino groups could be reduced. first ornithine-acylated derivatives showed ic50 values between 11-35nm enabling for the first time 18f-radiolabeling of small cxcr4 antagonists for pet imaging in vivo. binding of ligands to integrins plays a major role in cell adhesion, migration, and signal transduction of cells. these interactions are important not only for normal cell functions, but also in pathogenic processes. the v 3 integrin for example is involved in tumor cell adhesion and osteoporosis. the association of ligands is specific and requires minimal recognition sequences. therefore, suppression of integrin activity using competitive inhibitors bears great pharmacological potential. the tri-peptide sequence rgd is a prominent recognition sequence of integrin ligands. two new cyclic pentapeptides were synthesized containing the tripeptide sequence rgd as well as 3-amino-cyclopropane-1,2-dicarboxylic acid monomethyl ester (acc) and valine varying only with respect to the stereochemistry of acc. both the (+) (all r) and (-) (all s) isomers of acc were incorporated. acc is a cyclic -amino acid as well as a cyclopropyl analogue of aspartic acid. biological tests with cell lines expressing mainly v 3 and v 5 integrin show a higher inhibitory activity of cyclo-(-arg-gly-asp-(+)acc-val-). in order to derive a structure-activity relationship of these two isomers, solution structures in dmso-d6 were investigated by nmr spectroscopy. subsequently, structural information was obtained by applying distance restraints derived from the nmr spectra in distance geometry/simulated annealing and molecular dynamics calculations. due to the rigidity of the cyclopropyl unit in acc, the structure of the cyclopeptide is significantly influenced by the integrated propane ring, thus explaining the different biological properties. integrins are an important family of cell adhesion molecules. currently, 24 members are known. among other functions, integrin α 4 β 1 is involved in inflammatory processes, leukocyte migration and tumor angiogenesis. the structure of its natural ligand vcam-1, including the binding loop sequence tqidspln, has been determined by x-ray crystallography. therefore, it is possible to apply the concept of spatial screening: using small cyclic peptides with structure inducing building blocks, the binding motif is presented in different well-defined structural arrangements. for this study, a series of cyclic penta-and hexapeptides based on the tqidspln sequence has been synthesized. β-homoamino acids, i.e. β 3 -amino acids with proteinogenic side-chains, have been incorporated as structure inducers for spatial screening. although β 3 -amino acids are supposed to prefer the central position of ψγ-turns, less data exist than for e.g. d-amino acids. apart from the structural characterization of potential high affinity ligands for integrin α 4 β 1 , a major goal of this work is to provide a better understanding of the influence of β 3 -amino acids on the structure of cyclic peptides. the structures of the peptide library have been investigated by nmr spectroscopy, followed by dg/sa and md calculations. the results substantiate the γ-turn inducing capability of β-homoamino acids, but also prove the formation of different turn structures in certain cases. a comparison to the x-ray structure of vcam-1 shows that the structure of the binding sequence has been successfully approximated by some of the peptides. biological activity tests should lead to meaningful structure-affinity relationships. neuropeptide y (npy) is a 36-amino acid peptide amide and binds to the so-called y receptors. its most dominant element is the c-terminal alpha-helix spanning amino acid residues 12-36. residues 1-10 form a polyproline helix with highly conserved proline residues at positions 2, 5 and 8, followed by a loop structure. the importance of the polyproline helix strongly varies between different receptor subtypes. it obviously plays no role in ligand binding at the y2 receptor subtype, whereas the n-terminal segment is of importance for ligand binding at y1 and y5. in order to further study the importance of the polyproline helix we introduced a conformationally constrained pyridone dipeptide mimetic at different single positions by solid phase peptide synthesis using fmoc/tbu strategy. the resulting peptides have been investigated in cell lines that selectively express y1 and y5 receptor, respectively. different methods including radioactive competitive binding assay, cd and nmr have been applied to investigate conformation and interaction of receptor and ligand. loss of affinity at the y1 receptor is independent of the position and about 10-, 20-and 30-fold, respectively, when introduced once, twice and thrice. introduction of the building block in position 8/9 leads to the most reduced affinity at the y5 receptor subtype but, surprisingly, affinity can partially be regained by introduction of the dipeptide at two additional positions. the position of the dipeptide is of greater importance at y5. these novel peptides clearly indicate the importance of proline residues and the structure of the n-terminus for ligand binding. interactions of src homology 2 (sh2) domains with phosphotyrosine (py) containing ligands is critical for regulating cellular processes. the cytosolic protein tyrosine phosphatase shp-1 contains two sh2 domains. an intramolecular interaction of the n-terminal sh2 domain with the catalytic (ptp) domain renders the enzyme inactive in the native state. binding of a py-ligand to shp-1 n-sh2 leads to a conformational shift and the dissociation of the sh2-ptp complex [1] . in previous studies we investigated the topographical and conformational preferences of the n-sh2 domain of shp-1 using conformationally restricted linear and cyclic peptides derived from the natural interaction partner ros py2267 [2] . we identified peptides that showed an increased binding affinity for the n-sh2 domain and partially inhibited ros-mediated shp-1 activity. on the basis of these results we hypothesized that an imperfect fit of the py+1 and py+3 side chains might be responsible for the inhibitory effect. in order to confirm this hypothesis we synthesized a new series of peptides and evaluated their biological activity. to better understand the role of each individual sh2 domain in the activation process we also determined the binding affinity against the c-sh2 domain and the activation profile of different shp-1 mutants. pull-down assays of the interactions of the py-ligands with full length shp-1 confirmed the results obtained for the binding to the individual sh2 domains. proteins are targets for photo-destruction due to absorption of incident light by endogenous chromophores. mass spectroscopic data presented evidence that structural modification observed upon irradiation of goat alpha-lactalbumin at 290 nm results from tryptophan (trp) mediated cleavage of disulfide bonds [1] . the aim of the recent studies is to define structural elements that direct the destructive influence of near-uv light on the disulfide bridges of proteins. most of the proteins of the immunoglobulin superfamily contain a so called triad, consisting of two s atoms, forming a disulfide bridge, and a single trp in their close vicinity [2] . we have indications that this arrangement gives rise to a photolytic degradation similar to that described in our earlier studies for goat alpha-lactalbumin [3] . we therefore investigated the influence of uv light on the single chain variable fragment (scfv) of a monoclonal antibody (82d6a3) [4] which contains two triads. the results showed that after irradiation of the wild type scfv (i) new bands (degradation products) appeared in electrophoresis experiments and (ii) the affinity for its antigen, von willebrand factor decreased. by site-directed mutagenesis, we modified the critical trp-residues to perform a parallel study on these mutants. background and aims: it is known that thrombomodulin has important function which prevents thrombus. we found kmylcvckn (m, n >= 2) peptides derived from thrombomodulin had strong anti-thrombus activity in our recent studies. these peptides formed two structures, parallel and anti-parallel, as dimers, we examined the relation between structure and activity. methods: two peptides of kkkylc(acm)vckkk and kkkkylcvc(acm)kkkk were synthesized by fmoc chemistry. dimer peptides were made by removing acm with iodine, after dissolving in 0.1 m tris hcl buffer (ph 8.0) and oxidizing the mixture of these synthesized peptides spontaneously. then three peptides shown in figure were separated using rp-hplc. the peptide concentration in normal human pooled plasma was 10 micro moles / l when measuring aptt (activated partial thromboplastin time). results: the anti-parallel formed peptide, peptide b, was prolonged aptt approximately 2.7 times, although two parallel formed peptide, peptide a and c, were not significantly different from the aptt of normal plasma. conclusions: these peptides have structure-activity relationship, we observed that the anti-parallel formed peptide had strong anti-thrombus activity. insect kinins share a highly conserved c-terminal pentapeptide sequence phe-xaa-xbb-trp-gly-nh2, where xaa can be tyr, his, ser or asn and xbb can be ala but is generally ser or pro. they are potent diuretic peptides that stimulate the secretion of primary urine by malpighian tubules, organs involved in the regulation of salt and water balance (1). the insect kinins preferentially form a cis-pro, type vi β-turn. insect kinin analogs containing tetrazole (1) and 4-aminopyroglutamate (2), both cis-peptide bond, type vi β-turn motifs, demonstrate significant activity in the in a cricket diuretic assay. in this study, we compare the diuretic activity of insect kinin analogs incorporating the four stereochemical variants of the 4-aminoglutamate (apy) motif. three of the insect kinin analogs incorporating the stereochemical variants, ( the need for new effective and to mammalian cells non-toxic antifungal agents increases in parallel with the expanding number of immunocompromised patients at risk for invasive fungal infections. in our laboratory we have produced a serie of low-molecular peptide derivatives of the general structure: x-arg-leu-nh-ch(ipr)-ch2-nh-y (where x and y were acyl groups with aromatic carbocyclic system). we have found and earlier reported that some of these display high antimicrobial activities against several clinically important gram-positive pathogenic bacteria. in this study we have by solution methods synthesized a group of low-molecular compounds and investigated their antifungal activity. the study included both candida and aspergillus species. we have found that some of the compounds were highly fungicidal. we also made a conformational study in which the residues were separately replaced by selected hydrophobic amino acids and their equivalents. the conformational study showed that the desirable stable intramolecular structure could only be formed in the presence of some vital components. this work was supported by grant ds/8350-5-0131-6. increased resistance of bacterial pathogens to currently employed antibiotics has resulted in efforts to develop antimicrobial compounds with new mechanisms of action. previously, we have synthesized some high potent antimicrobial compounds based upon the n-terminal binding fragment of human cystatin c. some derivatives of the general structure: x-arg-leu-nh-ch(ipr)-ch2-nh-y (1) (where x and y were acyl groups with aromatic carbocyclic system) have displayed the broad antibacterial spectrum and high activity against several clinically important gram-positive pathogens, including multi-resistant staphylococci. herein, the synthesis and structure -antibacterial properties relationship for two series of analogues of 1 are presented. the x and y groups in 1 were replaced by selected substituents with various geometry and distance between aromatic moieties and carbonyl. we have established the general structural features which the discussed class of peptide derivatives should possess in order to displaying the particular antimicrobial activity. this work was supported by grant ds/8350-5-0131-6. we have synthesized beta-endorphine-like decapeptide immunorphin sltclvkgfy which corresponds to the 364-373 sequence of the heavy chain of human igg. immunorphin was found to be a selective agonist of non-opioid (naloxone-insensitive) beta-endorphin receptor. the purpose of this study was to prepare [3h]immunorphin and characterize by its using the non-opioid beta-endorphin receptor on mouse peritoneal macrophages and membranes isolated from various rat organs. by use of tritium-labeled immunorphin ([3h]sltclvkgfy) with specific activity of 24 ci/mmol, non-opioid beta-endorphin receptors were revealed and characterized on mouse peritoneal macrophages and rat myocardium, spleen, adrenal, and brain membranes. since dehydroamino acids are quite reactive and various thiol nucleophiles are known to add to their double bonds [1, 2] , we hoped that these compounds might act as alkylating inhibitors of cathepsin c (dipeptidyl-peptidase i). its main function is protein degradation in lysosymes, but it is also found to participate in the activation of neuraminidase and proenzymes of serine proteinases (leukocyte elastase, cathepsin g, granzyme a) [3, 4] . it is well known, that phosphonodipeptides structural analogues of synthetic substrates of cathepsin c are the model substances in designing the new inhibitors of this enzyme. for that reason we have undertook the synthesis, theoretical and structural investigations of phosphonic analogues of dehydropeptides. gly-∆zphe-abupo(ome)2 gly-∆zphe-alapo(oet)2 gly-∆zphe-leupo(ome)2 gly-∆zphe-valpo(oet)2 gly-∆zphe-glypo(ome)2 gly-∆zphe-nbupo(oet)2 the structure and conformational preferences in this group of peptides had been investigated by mean of nmr techniques. in order to find the interactions between compounds-enzyme (cathepsin c) and interpret the results of biological test, the molecular modelling methods had been used. the interaction of v 3 integrin receptor with its ligands is selectively implicated in various processes, like angiogenesis, bone-formation, tumor genesis and tissue-genetic migration of embryonic cells. several cyclic rgd pentapeptides are known as selective ligands for v 3 integrin receptor. the aim of this study was to prepare a new conjugate, composed of the cyclo[rgdfc] derivative and a branched chain polycationic polypeptide, poly[lys(dl-alam)] (ak). the cyclopeptide was prepared on 2-cl-trityl chloride resin by fmoc/tbu strategy. the "head-to-tail" cyclisation was achieved in a diluted solution of dmf in the presence of bop and hobt coupling reagents and diea base. coupling of the cyclopeptide to ak polymer was carried out by thioether linkage. adhesion properties of soluble cyclic rgd peptides and their plate-immobilized forms were studied. free cyclopeptides evoke aggregation of cultured primary neural and cloned neural stem cells, while their plate-immobilized forms fail to support cell adhesion. on the contrary, in case the newly synthesized ak-c(rgdfc) conjugate such induction of cell aggregation was not observed. whereas immobilizing this derivative to either glass, or plastic was found to support cell-attachment in case of various cell types. in addition, all cell lines investigated -including also the primary neural cells -attached to ak-c(rgdfc) coated surface and survived, grew or differentiated even in the absence of serum. our data suggest that cyclic rgd -polypeptide conjugates represent a new tool to investigate selective cell adhesion and may provide a novel scaffold-material for directed cell-seeding. in the ph-induced channel closure in combination with the pip2 interactions. however, their detailed regulations are still remaining unclear. therefore, in the present study, we investigate these crucial residues with electrophysiological recordings and rationally designed mutagenesis based upon our structural analysis of kir1.1 tetramer. lys-80 is located fairly close to the intracellular channel gate and protrudes its long side chain positive charge into the pore. this may interfere with the potassium flow by providing repulsion charge while ph is lowered, which pushes the channel towards its closed state. mutation to met-80 therefore reduces such ph-sensitivity. on the other hand, arg-188 is supposed to be responsible for the maintenance of channel opening in the presence of pip2. loss of positive charge at this site may lead to the enhanced ph-sensitivity due to an abolished or reduced pip2 interaction. more interestingly, the double mutant for both sites reveals a compensation scenario. in combination with the discussion for the role of previously known r-k-r triad, our data provide very clear structural explanation for the exact functional roles of these basic residues in the regulation of ph-sensitive channel gating. mouse obese cart peptides are neurotransmitters involved in feeding, stress and endocrine regulation. leptin, a long-term adiposity signal, upregulates expression of cart in the hypothalamus. recent findings of co-localization of cart and cholecystokinin (cck)-a receptor (responsible for satiety effect of cck) in brain and gastrointestinal tract suggest a neurochemical link between cart peptides and cck. in normal fasted mice, cart(61-102) peptide decreased food intake after intracerebroventricular (icv) administration in a dose-dependent manner. anorectic effect of cart peptide was enhanced by peripherally administered cck-8, while cck-a receptor antagonist, devazepide blocked the effect of cart peptide on food intake. we used two mouse obesity models in this study: monosodium glutamate (msg) and diet-induced obese (dio) c57bl mice. both dio and msg mice had substantially increased fat to body mass ratio compared to their controls and were hyperleptinemic. msg mice were hypophagic and neither cart peptide nor cck-8 and devazepide had any effect on food intake of these mice. dio mice fed high-fat diet showed slightly decreased sensitivity to central administration of cart peptide, effect of cck-8 on food intake was preserved. in conclusion, cart peptide and cck-8 showed a synergistic effect on feeding in control mice that pointed to their probably integrated action in the central nervous system. analogously, devazepide suppressed cart anorectic effect. in msg obese mice, effects of both cart peptide and cck-8 on food intake were diminished due to disrupted signaling in hypothalamus. in dio mice, additive effects of cart and cck-8 were partly preserved inspite of hyperleptinemia and increased adiposity. b. chini 1 , s. stoev 2 , l.l. cheng 2 , m. manning 2 , were subsequently shown not be selective for the rat v1b receptor [2] . peptides a-d served as excellent leads to the design of selective agonists for the rat vp v1b receptor [3] . replacement of the arg8 residue in a-d by lys, orn, dap and dab, led to the first potent and selective agonists for the rat v1b receptor [3] . we now report that three of these; d the aim of the de novo peptide synthesis and the incorporation of cofactors is the construction of artificial protein models. these model systems can be used for understanding the structure-function relationship of native proteins and might open a way for possible applications. protegrin-1 (pg-1) is an 18-amino acid peptide with an amidated c-terminus, which forms an antiparallel beta-sheet, constrained by two disulfide bridges. the native sequence of pg-1 is highly cationic, containing six positively charged arginine residues. it was found that the structural features such as amphiphilicity, charge and shape are important for the cytolitic activity of pg-1. in this study we investigate the sar (structure activity relationship) of two pg-1 analogues: rglcycrgrfcvcvg-nh2 (bm-1) and rglcyrprfvcvg-nh2 (bm-2). our antimicrobial activity studies of these peptides show that the bm-1 peptide is active against microbe species as well as the native pg-1, whereas the bm-2 is completely inactive. the bm-1 analoque is shorter than native pg-1 and contains only three arginine residues, therefore is much cheaper in the chemical synthesis, what could be an advantage of this antimicrobial peptide. the conformational studies of both analogues were performed by using 2d 1h-nmr technique (in dmso-d6) and molecular dynamics studies. the 3d solution structure of both analogues was established using interproton distances and torsion angles. for simulated annealing calculations the xplor program was used. our conformational studies show that the bm-1 forms a regular beta-hairpin structure, which is very similar to that of the native pg-1 peptide, whereas the bm-2 analogue is very flexible, what could be a reason of the antimicrobial inactivity. copper amine oxidases (ec 1.4.3.6) catalyze the oxidative deamination of primary amines to the corresponding aldehydes, ammonia and hydrogen peroxidase. these enzymes are ubiquitous, occurring in micro-organisms, plant and animals. activity of this enzyme increases under various stress conditions including thermal and water stresses. although lsao is not a thermostable enzyme, it is in maximum stability and activity above physiological temperatures. in this study we have investigated the kinetics of thermal denaturation of lentil seedling amine oxidase (lsao) by measuring its denaturation constant (kden) at various temperatures from 37 to 67 degrees centigrade in 100 mm phosphate buffer, ph 7.0. the results of thermal inactivation curves as well as measuring of a280 at various temperatures were used to calculate kden. moreover, activation energy (ea) for denaturation reaction was obtained from corresponding arrhenius plot. our results showed that unfolding process started to occur at 56 degree centigrade and ea of denaturation was changed at 65 degree centigrade proving a dominant conformational change of the enzyme at this temperature. the results of the kinetic study are coincident with previously reported equilibrium studies denoting the optimum and melting temperature of the enzyme are 56 and 65 degree centigrade, respectively. development and advancing of enzymatic processes used for production and modification of natural polysaccharides are now major biochemistry challenges. the paper investigates enzymatic systems in invertebrates, in particular, an enzymatic complex obtained from the hepatopancreas of red king crab paralithodes camtschaticus, and clarifies its effect on the mechanism of chitin and chitosan hydrolysis. chitinolytic activity was estimated with spectrophotometer using 4-(dimemylamine)-behzaldehyde method by the concentration of n-acetyl-d-glucosamine which is educed under chitinolysis. total glycolytic activity was defined by the sum of n-acetyl-d-glucosamine and d(+)-glucosamine in the reaction with potassium hexaferricyanide (iii). content of d(+)glucosamine in the hydrolysates of chitin and chitosan was estimated by highly effective reverse-phase liquid chromatography (helc) of aminosaccharides with ortho-phthalaldehyde. the paper studies the process of chitin and chitosan glycolysis and the effects of different factors (ph, temperature and time of incubation, enzyme/substrate ratio) on the total glycolytic activity of the enzymatic complex from crab hepatopancreas, which is compared with a previously studied proteolytic and exochitinase activities. a mechanism of enzymatic hydrolysis of chitin and chitosan is suggested. study results allowed the following conclusions concerning glycolytic and deacetylase activity of ep: 1) ep induces the formation of a monomer (n-acetyl-d-glucosamine) and oligomers (chitin and chitosan) with low deacetylation. thus, ep is characterised by a marked endochitinase (endochitosanase) activity; 2) n-acetylglucosamine deacetylase and, apparently, exochitosanase activity was not revealed; 3) it was found that chitinase and protease activities of ep are associated with different enzymes. [background] in opioids, the n-terminal amino acid 2',6'-dimethyl-l-tyrosine (dmt) enhances bioactivity by orders of magnitude. c-terminal modification of the dmt by a methyl group, h-dmt-nh-ch3, exhibited µ-opioid receptor affinity (kiµ = 7.5 nm) equivalent to that of morphine; however, antinociception was only 0.64-0.85% [1] . dmt plays an important role in the message domain to anchor opioid ligands into the active site of opioid receptors, specifically to trigger biological activity by the µ-opioid receptor. [methods] dimerization of dmt through diaminoalkanes [2] or 3,6-bis-(aminoalkyl)-2(1h)-pyrazinone produced potent opioidmimetics with high affinity for µ-opioid receptors (kiµ = 0.02-0.115 nm), agonism (gpi, ic50 = 1.3-1.9 nm), and antinociception in mice after systemic and oral administration, which verified passage through the epithelial membranes of the gastrointestinal tract and blood-brain barrier [3] . (1-aminocycloalkane-1-carboxylic acid) . in this case the ring consists of five atoms. knowing that acylation of the nterminus of several known b2 blockers with a variety of bulky groups has consistently improved their antagonistic potency in the rat blood pressure assay, the apc substituted analogues were also synthesized in n-acylated form (with 1-adamantaneacetic acid (aaa)). the activity of eight new analogues was assayed in isolated rat uterus using a modified holton method in munsick solution and in rat blood pressure tests. the results clearly demonstrated the importance of the position in the peptide chain into which the sterically restricted apc residue was inserted. apc at positions 7 led to preservation or reduction of antagonistic qualities, respectively. acc at position 8 enhanced antagonistic qualities in blood pressure test and led to preservation of activity in antiuterotonic test.. in most cases acylation of the n-terminus led to enhancement of antagonistic potencies. our findings offer new possibilities for designing new potent and selective b2 blockers. background: during the course of developing opioidmimetic analgesics, data revealed that the n-terminal residue 2',6'-dimethyl-l-tyrosine (dmt) plays an important role in anchoring opioid ligands in the active site of opioid receptors. as a single residue c-terminally extended with an aminomethyl group exhibited µ-opioid receptor affinity (kiµ = 7.5 nm) similar to morphine; however, antinociception was only 0.64-0.85% [1] . in order to develop potent µ-opioid agonists, the dimerization of tyr or dmt through diaminoalkanes [2] or 3,6-bis-(aminoalkyl)-2(1h)-pyrazinones [3] resulted in production of unique opioidmimetics with high receptor affinities and potent biological activities [3] . methods: the synthesis of opioids and opioidmimetics and the determination of their receptor binding characteristics were performed as described previously [1] [2] [3] . results and conclusion: newly synthesized 3-(tyr-nh-butyl)-6-(tyr-nh-propyl)-2(1h) pyrazinone and 3-(tyr-nh-propyl)-6-(tyr-nh-butyl)-2(1h) pyrazinones (i and ii) exhibited fairly high binding affinity towards µ-opioid receptor (kiµ = 7.6 and 27.4 nm, respectively). replacement of tyr with dmt in i and ii gave opioidmimetics iii and iv (kiµ = 0.021 and 0.051 nm, respectively); they exhibited 361-and 537-fold higher binding affinity than the tyr derivatives. while iii is a dual µ-/δ-opioid agonist, iv is only a µ-opioid agonist. these findings pave the way to design additional µ-opioid receptor agonists and antagonists for therapeutic application. divalent cations have been known for a long time to influence significantly binding to receptors and biological activity of the peptide oxytocin (ot). there is very low binding of 3h-ot to the receptors in the absence of these ions. it has been speculated where the divalent cations work. recently an article appeared showing formation of a complex divalent cation-ot and stressing the importance of n-terminal amino group for binding and activity [1] . however deamino analogues of ot are also very active and their binding is also influenced by divalent cations. we have studied ot, deaminooxytocin (dot) and an ot antagonist (antag) by means of electrospray ms and we have observed that all these compounds form molecular adducts with zn2+, mg2+, mn2+ and ca2+. in binding experiments using 125-i antag, the quantity of tracer bound to membranes of hek cells having stable expressed human ot receptor strongly depends on the character and concentration of divalent ions. displacement curves using unlabelled antag do not change in the absence or presence of 10 mm of tested divalent ions. on the other hand, displacement curves using unlabelled ot and dot are shifted to the left in the presence of mg2+ and mn2+, and to much lesser extent by zn2+ and ca2+. all this points to the idea that the divalent ions do work on the site of membrane receptors. biologically active peptides exhibit multiple conformations in solution. thus, the synthesis of conformationally restricted analogues is a valuable approach for determining structure -activity relationships. restrictions can be imposed e.g. through the formation of cyclic structures within the peptide framework by disulfide bridges, or by substitution of chosen amino acid residues that limit conformational freedom, thus forcing the peptide backbone and/or side chains to adopt specific orientations. in recent years, conformationally constrained analogues of bioactive peptides seem to be a feasible approach to providing useful informations concerning threedimensional structure of such compounds which, in turn, could rationalize our knowledge about structure-biological activity relationships and thus help to design peptides with desired pharmacological properties. steric restrictions can be introduced by the formation of cyclic structures within the peptide backbone or by incorporation of amino acids with limited conformational freedom, which in turn results in specific orientations of the peptide backbone and its side chains. another approach to reduce the flexibility of the analogue is substitution of chosen amino acids with various types of pseudopeptides prepared trough short-range cyclizations. the present work is a part of our studies aimed at clarifying the influence of sterical constraints in the n-terminal part of arginine vasopressin (avp) and its analogues on the pharmacological activity of the resulting peptides. we describe the synthesis of four new analogues of avp substituted at positions 2 and 3 or 3 and 4 with two diastereomers of 4-amino-pyroglutamic acid and four peptides in which we combined the above modification with the placement of 3mercaptopropionic acid (mpa) at position 1. all the peptides were tested for their in vitro uterotonic, pressor and antidiuretic activities in the rat. different strategies to modulate shp-1 activity protein tyrosine phosphatase shp-1 consists of two sh2 domains n-terminal to the catalytic (ptp) domain and a short c-terminal tail. the binding of a py-ligand to the n-sh2 domain is required for an efficient activation of shp-1 phosphatase activity. the specificity of the shp-1 sh2 domains is determined by the py-residue (position 0) and residues at positions -2, +1 and +3. combinatorial peptide library methods revealed different classes of consensus sequences for both sh2 domains [1, 2] . in addition, the importance of residues c-terminal to py+3 (+4 to +6), in particular for binding to the n-sh2 domain, has been demonstrated [3] . together with investigations of the determinants for optimal sh2 domain binding and stimulation/inhibition of shp-1 activity [4] , these informations were useful for the generation of different strategies for effectors of shp-1 activity. peptides cyclized between different positions of the general consensus py-2 to py+3 were synthesized and evaluated with respect to n-sh2 domain binding and stimulation of phosphatase activity. structure-activity studies have revealed that the specificity of an integrin towards its rgd-containing ligands can be evaluated through the distances between the cβ atoms and/or the distance between the charged centers of arginine and aspartic acid as well as, the pseudo-dihedral angle (pdo), composed by the r-cζ, r-cα, d-cα and d-cγ atoms, which defines the relative orientation of the arg and asp side chains. in a previous study [1] , the antiaggregatory activity of rgd peptide analogues, i.e. their ability to act as fibrinogen receptor αiibβ3 antagonists, was correlated with the above structural criteria. our results suggested that the fulfillment of the criterion -45ο < pdo < +45ο is a prerequisite for an analogue to exhibit activity. in the present study, we examine the above criteria to rgd-containing 15peptides, derived from the active sites of the ecm proteins fibrinogen, fibronectin and vitronectin, as well as, from the cryptic rgd site of von willebrand factor. the correlation of the structural data with the biological activity of compounds, are in good agreement with the previously mentioned -45ο < pdo < +45ο criterion. furthermore, our results show that the differences in activity of compounds, which display similar distances between the charged centers of arg and asp, can be better evaluated by the pdo structural criterion. acknwolegments : this work was supported by grants from eu and the hellenic ministry of education ( heraklitos). references : the gpiib/iiia receptor, which is a member of the integrin family, is the most abundant receptor in the surface of platelets and can interact with a variety of adhesive proteins including fibrinogen, fibronectin and von willebrand factor. fibrinogen binding on gpiib/iiia is an event essential for platelet aggregation and thrombus formation. mapping of the fibrinogen binding domains on gpiib subunit suggested the sequence 313-332 as a putative binding site [1] . this region was restricted to sequence gpiib 313-320 (ymesradr) using synthetic octapeptides overlapping by six residues [2] . the ymesradr octapeptide inhibits adp stimulated human platelets aggregation and binds to immobilized fibrinogen. in this study we present the conformational analysis of three synthetic analogues yaesradr (a2) ymesaadr (a5), and ymesraar (a7), using nmr spectroscopy and distance geometry calculations. common structural characteristic of peptides a2 and a7 is the interaction between the side chains of arg5 and glu3, however in a2 the guanidino group of arg5 seems to form salt bridges with both glu3 and asp7. peptide a5 is stabilized only by a week interaction between arg8 and glu3 side chains. the interactions between the residue side chains provoke different overall shape of the three molecules. the most populated structural family of a2 exhibits a π backbone shape, a5 a turn around -s4a5-, while a7 an almost extended shape. background and aims: endomorphin-2 (em-2: h-tyr-pro-phe-phe-nh2), endogenous opioid peptide isolated from bovine and human brain, has high affinity and selectivity for the mu receptor and produces potent and prolonged analgesia in mice [1] . in this presentation, the incorporation of ethylene-bridged phe-phe unit (eb[phe-phe]) or piperidine carboxylic aid (pic) in position 2 was carried out to obtain more potent agonist or antagonist with stability against dipeptidyl peptidase iv (dpp iv). methods: the synthesis of eb[phe-phe] unit was achieved according to the procedure of lammek b. et al. [2] protected peptides were synthesized by a solution method using boc-chemistry. the final products were identified by maldi-tof mass spectrometry and elemental analyses. the receptor binding affinity of peptides was assessed by radio-ligand receptor binding assay using mu and delta opioid receptors from rat brain membranes or cos-7 cell membranes expressing each opioid receptors. muc2 glycoprotein, produced by the epithelium of the colon, built up mainly of repeat units of 1ptttpitttttvtptptptgtqt23, can be underglycosylated in colon carcinoma. we have been studying the epitope structure of the muc2 repeat unit with the mucin peptide specific mab 996 monoclonal antibody. this antibody recognizes the 18ptgtq22 sequence as minimal, and 16ptptgtq22 as optimal epitope. our interest lies in the modification of this epitope with maintained or enhanced specificity, and we aim to clarify the effect of different epitope modifications on mab 996 antibody binding: a) amino acid changes in the flanking region, b) glycosylation in the epitope core and in the flank. for this we have prepared a) libraries of ax(1)ptgtqaa and atptgtqx(2)a peptides, and x(1)ptgtqx(2) heptapeptides based on the antibody binding properties of the libraries; and b) glycopeptides pt(galnac)ptgtq, ptpt(galnac)gtq and ptptgt(galnac)q. the peptides were prepared by solid phase synthesis; after purification, esi-ms and amino acid analysis characterisation their antibody binding properties were studied by competitive elisa. our results show that a) although all amino acids in positions x(1) and x(2) resulted in antibody binding; in position x(1) hydrophobic, in x(2) aromatic residues provided stronger binding than that of the native peptide; b) glycosylation on thr(17) did not influence the binding of mab 996, but on thr(19) the presence of n-acetyl-galactosamine, interestingly, slightly increased the antibody recognition. these findings could be useful in designing synthetic peptide vaccines for tumour therapy. histidines play essential role in binding of biological metal ions, either in small or macromolecular chelating molecules, e.g. in metalloenzymes. therefore the low molecular weight polyhistidine type ligands are of potential importance as model substances. continuing our investigations on a novel branched oligopeptide type ligand -(his)4(lys)2lys-nh2 -prepared by solid phase peptide synthesis, we investigated the metal ion binding properties with zinc(ii) and copper(ii). the eight primary metal-binding sites are the four imidazole and four ammine groups on the ligand. phpotentiometric titrations revealed, that up to ph 8 all these donor atoms loose their protons on increasing ph. the competition between the protons and the metal ions results the decrease of pka values to about 1-3 in the case of copper(ii) and to about 4-6 in case of zinc(ii) ion. this reflects the higher stability of the complexes formed with copper(ii) in spite of the weak axial coordination that seems to occur in zinc(ii) complexes. combined potentiometric, spectrophotometric, cd and nmr spectroscopic methods were utilized to investigate the speciation and the structure of the complexes formed in aqueous solution. the prepared cu(ii) complexes cleaved dna, but it is not known whether in oxidative or in hydrolytic manner. because of this ambiguity further studies with zn(ii) complexes will be undertaken. this work has received support through sapstclg97697 nato collaborative linkage grant and from the hungarian science foundation (otka t43232). lgr8. further studies have shown that in both male and female gonads, insl3 and lgr8 represent a paracrine system important for meiosis induction in the ovary and male germ cell survival in the testis. thus insl3 may have clinical applications in fertility management. we undertook to determine the key structural elements responsible for its unique actions. methods: alanine-scanned analogues of human insl3 and mimetics of the b-chain alone were prepared by solid phase peptide synthesis. each was subjected to cd spectroscopy for secondary structure analysis and assayed for in vitro lgr8 binding and activation activity. the tetrapeptide h-dmt-d-arg-phe-cbp was found to be a selective µ agonist [ic50 (gpi) = 78.8 ± nm] with 40-fold lower potency than the corresponding, highly potent tiq4-tetrapeptide, but with still 3-fold higher potency than leu-enkephalin. in conclusion, we developed selective, cbp-containing δ antagonists and µ agonists with significant potency. recently, we described the syntheses and biological activities of several opioid peptide analogues that contained the n-terminal sequence 1-4, common to dermorphin and deltorphin. some of them showed very high agonist potency both in the gpi assay and in the mvd assay [1, 2] . in this work, we designed new analogues in which the sequences were elongated at the c-terminal to obtained the full sequences of dermorphin (a) and deltorphin (b). the syntheses of compounds and their biological activity profiles will be discussed. background and aims: endomorphin-2 (em-2: tyr-pro-phe-phe-nh2) is very potent endogenous opioid peptide, which exhibits high affinity and selectivity for the mu-opioid receptor [1] . previously, we had reported that [ac3c2]-em-2 containing 1-aminocyclopropane-1-carboxylic acid (ac3c) exhibited higher affinities than em-2 for the mu-opioid receptor [2] . in order to clarify that the substitution of 1-aminocycloalkane-1-carboxylic acids (acnc: n indicates the number of carbon atoms in a ring) for pro in position 2 of em-2 is efficient to obtain higher affinity for the mu-receptor, we synthesized . therefore, the replacement of pro to ac3c and ac4c will be efficient to make these analogs adopt bioactive conformation and exhibit high affinity for mu-receptor. in the past few years, many attempts have been made to prepare a synthetic insulin. the biological activity of insulin is known to be closely related to the c-terminal octapeptide fragment of its b-chain.it was found that b23 gly and b24 phe were present in all insulins so far obtained from various animal species indicating the significance of these two residues.it would therefore seem desirable to study the effect of each of these two amino acid residues or both on biological activity of the octapeptide fragment of the b-chain. a heptapeptide arg-phe-tyr-thr-pro-lys-ala-och3, corresponding to (b22-b30) insulin des gly23-phe24, and an octapeptide arg-phe-phe-tyr-thr-pro-lys-ala-och3, des gly23 were synthesized using the solid phase method. the c-terminal ends of both peptide were converted to methyl ester by transesterification cleavage from the resin. the side chain protecting groups were removed by hf. manual counter current distribution method was used for purification of the free peptides. the way to solve the evaluation of tyrosine containing peptide was studied. the free methyl ester peptides were administered for insulin-like activity test by glucose metabolism in the rat fat cells technique in vitro. aim of this study is to develop peptides as useful tools for degradation of synthetic dyes, which are often pollutants. we focused our interest in peroxidases, a class of enzymes reported to efficiently degrade azo and anthraquinonic dyes. in particular, the fungus versatile peroxidase (vp) of pleurotus eryngii can perform this degradation. therefore, our goal is the synthesis of a peptide based on this peroxidase able to emulate its biological function. the linear and cyclic peptide sequences were derived by the theoretical model of vp [pdb: 1a20], which determined the amino acids fundamental for the desired function of the active sites. in particular, the residues instrumental for the coordination of the heme, the mn binding site, and the long range electron transfer pathway [1] , were pin-pointed. moreover, we calculated the radius of the heme cavity. the next step was the synthesis of these peptides in order to verify the coordination of the heme and optimize their sequences. the syntheses were carried out by solid-phase following the fmoc/tbu strategy. because of purification difficulties of the fully-protected peptide, we undertook an alternative synthetic pathway, based on a solid phase head-to-tail cyclisation strategy, following the fmoc/tbu/allyl three-dimensional protection scheme [2] . next steps will be to test the coordination properties of the synthetic peptides, with respect to the heme, and further computational studies based on the new model of pleurotus the calcium plays an important role in biochemical pathways. it binds to enzymes and proteins in a different process. aspartic (asp, d) and glutamic (glu, e) acid side chains are the main ligands of calcium, but the contribution of the backbone carbonyl groups in the binding is also important. generally the binding places in the proteins are an unstructured loop between two helixes (310-or alpha-helix). the common sequence is the so-called ef-hand motif, which contains 12 amino acids [1] . it is already known that some proteins also bind calcium with a non-ef-hand loop. for example alpha-lactalbumins have a ten amino acid long sequence for binding [2] . it is an asp rich sequence where 5 asps are closer to each other than in ef-hand motif (-k79fldddltdd88-) but only 3 asps side chains take part in calcium coordination. we constructed a series of cyclopeptides to mimic the loop structure of alpha-lactalbumin [3] . in this study we focus on determining the importance of conservative amino acids within the ca2+ binding loop of this protein, using microcalorimetry (itc). the itc measurements were performed in different organic solvents and at different temperature. the synthesis of fatty acids in adipose tissue. in this article, we present the solution structure of gip in water and tfe/water determined by nmr spectroscopy. the calculated structures are characterised by the presence of an -helical motif between residues ser11-gln29 and phe6-gln29 respectively. the helical conformation of gip is further supported by cd spectroscopic studies. six gip(1-42)ala1-7 analogues were synthesised by replacing individual n-terminal residues with alanine. alanine scan studies of these n-terminal residues showed that the gip(1-42)ala6 was the only analogue to show insulin secreting activity similar to that of the native gip. however, when compared with glucose its insulinotropic ability was reduced. for the first time, these nmr and modelling results contribute to the understanding of the structural requirements for the biological activity of gip. a knowledge of the solution structure of gip and of the role of its individual residues will be essential in the understanding of how they interact with the gip receptor. efrapeptins are pentadecapeptides produced as a mixture of six closely related analogues (efrapeptin c-g) by the fungus tolypocladium niveum and other members of this species. they consist predominantly of the nonproteinogenic amino acids -aminoisobutyric acid (aib), isovaline (iva), -alanine ( ala) and pipecolic acid (pip), have an acetylated n-terminus and bear an unusual cationic c-terminal headgroup derived from leucinol and 1,5-diazabicyclo[4.3.0]non-5-ene. efrapeptin c is a competitive inhibitor of the f1-atpase and active against the malaria pathogen plasmodium falciparum. an anti-proliferative effect was also reported. conformational analysis of efrapeptin c in trifluoroethanol and dimethylsulfoxide was conducted to obtain structure-affinity relationships. the absence of amide-and -protons resulted in an imperfect assignment and unsatisfying conformational study. specific deuteration of methyl groups in aib did not simplify the assignment. cd and ft/ir spectra hint to helical or beta-turn secondary structures as main structure elements. residual dipolar couplings (rdc) were measured in a stretched cross-linked poly(dimethylsiloxane) gel in dichloromethane. the impact of the rdc on the conformational analysis led to an improved high resolution structure from simulated annealing protocols and consolidated the formation of a helical structure of efrapeptin c in nonpolar solution which is comparable with the binding pocket of the f1-atpase. finally, the dynamics of the resulting structures was studied using the gromos96 force field in explicit solvent. serotonin selective reuptake inhibitors (ssris) are currently among the most frequently prescribed therapeutic agents of depression. their therapeutic use includes also obsessive-compulsive disorder, panic disorder, bulimia. the serotonin transporter (sert) is the target of serotonin selective reuptake inhibitors (ssris). altough the inhibition is the proximal event in antidepressant action, the clinical benefit of antidepressant medications requires weeks of continuous dosing, indicating that their mechanism of action involves events downstream from acute transporter blockade. long-term effects of ssri treatment may be due to changes in intrinsic properties of sert structure, function, or regulation. thus, understanding the mechanism of action of sert remains a primary goal in the search for developing novel treatments for diseases associated with serotonergic dysfunction. in the present study experimentally determined ligand selectivity of the buspirone analogues toward the serotonin transporter was theoretically investigated on the molecular level. the model of serotonin transporter based on the crystal structure of bacterial homologue from aquifex aeolicus (leutaa) was constructed using the traditional homology modelling approach. a series of docking experiments with ssri's were conducted, using interactive molecular graphics techniques combined with energy calculations and analysis of the transporter-ligand complexes. structural information about the serotonin transporter and its molecular interactions with ssri's is important for understanding the mechanism of action of these drugs and for development of drugs with improved potency and selectivity. the protein kinase c (prkc) is a member of a super-family of the eukaryotic receptor protein kinases. it forms dimers and is anchored in the membrane, with a cytoplasmic kinase domain and an external domain, presumably acting as a sensor. prkc enables formation of biofilms of bacillus subtilis which show a high degree of spatial organization. they colonize various surfaces and produce complex antibiotic resistant communities. prkc acts as a ser/thr kinase with features of the receptor kinase family of eukaryotic hanks kinases. our current study involved theoretical modeling of the protein kinaze prkc complexes with the modified atp. the ligands were selected from a set of molecular probes developed by k. shah and coworkers [1] . each modified atp molecule was docked to the active site of the kinase molecule using autodock genetic algorithm procedure. the optimized structures of the complexes were submitted to the molecular dynamics simulations in the amber force field. we obtained four optimized structures of prkcc complexes in water. the results suggest the great similarity of our complexes with human cyclin-dependent kinase 2 [1] complexes. background and aims. indolicidin is a 13-residue antimicrobial peptide, which was isolated from bovine neutrophils. this molecule possesses a wide spectrum of antibacterial, antifungal and antiviral activity, furthermore it has also haemolytic effect. data derived from structural investigations led to considerably diverse conclusions regarding the secondary structure of this peptide, therefore the aim of this study was to examine the effect of cis-trans isomerization on the conformational properties of this antimicrobial peptide. methods. the conformational analysis of indolicidin containing cis or trans xxx-pro peptide bonds was performed by simulated annealing calculations with the use of amber force field. results. for the conformers of indolicidin with cis or trans xxx-pro peptide bonds, the evolving secondary structural elements were examined and poly-proline ii helix and type vi beta-turn were identified. in the case of this peptide, various intramolecular interactions may play an important role in stabilizing the structure of conformers. therefore the presence of the h-bonds between backbone atoms, the aromatic-aromatic interactions between the side-chains of trp amino acids and the proline-aromatic interactions between the side-chains of trp and the pyrrolidine rings of pro amino acids was investigated. conclusions. the conformational comparison of the peptides possessing cis or trans xxx-pro peptide bonds resulted in different secondary structural elements for both isomers, which are the poly-proline ii helix and type vi beta-turn for the trans and cis isomers of indolicidin, respectively. the occurrences of various intramolecular interactions are in agreement with the observed secondary structures. we have shown the monte carlo conformational search using macromodel is useful for conformational study of oligopeptides prepared from alpha, alphadisubstituted alpha-amino acids. moreover, we have studied conformational analysis of oligopeptides containing chiral alpha, alpha-disubstituted alphaamino acids to predict the helical screw sense of helical structures. here we report computational study on conformation of oligopeptides containing cyclic alpha, alpha-disubstituted alpha-amino acids with side-chain chiral centers. background and aims. the homopolymeric amino acids (hpaas) are polypeptides consisting of the same amino acids. some of them play a relevant role in the formation of several neurodegenerative diseases. most probably the poly-(ala) and poly-(gln) are the best representatives of these peptides because of their important biological effects. our aim was to perform conformational analysis and structural investigation of these two hpaas. methods. to explore the conformational spaces of the peptides, simulated annealing (sa) and random search (rs) calculations were carried out using amber force field. two different forms of the hpaas were modelled: either with charged n-terminal amino group and c-terminal carboxyl group, or with the n-and c-termini blocked by acetyl and n-methyl amide groups, respectively. results. for the conformers obtained by sa and rs calculations, the occurrences of various secondary structural elements like different types of beta-turns, gammaand inverse gamma-turns, alpha-helix, 310-helix, poly-proline ii helix and beta-strand were investigated. in the cases of various helices and beta-strand, segments with different lengths characterized by these secondary structures were determined along the entire sequence of peptides. for the conformers of the hpaas, the intramolecular h-bonds formed between the backbone atoms as well as between the backbone and side-chain atoms were identified. the vasopressin and oxytocin receptors (v1ar, v2r and otr) are membrane-embedded proteins belonging to the large family a g protein-coupled receptors (gpcrs). they are involved in crucial physiological functions as the regulation of water metabolism, control of blood pressure and stimulation of labor and lactation, mediated via v2r, v1ar and otr, respectively. as such, they are involved in a number of pathological conditions and are important drug targets. understanding their inhibition and activation mechanisms may improve design of ligands capable of selective stimulation or blockade of the respective receptors presenting the therapeutic targets. to investigate the otr, v1ar and v2r interactions with agonists and antagonists thirty computer models of receptor-ligand complexes have been modeled via docking and molecular dynamics (md) and analyzed in details. the receptor models were built on rd crystal structure template or using the coordinates of mii-gtα(338-350), for non-active and activated models, respectively. the ligands (arginine vasopressin, oxytocin, desmopressin, atosiban ([mpa1,d-tyr(et)2,thr4,orn8]ot) and barusiban (mpa1,d-trp2,ile3,allo-ile4,asn5,abu6,mol7) were docked into the receptors. the complexes have been embedded into the hydrated popc bilayer and submitted to 1ns unconstrained md in the amber force field. the relaxed systems have been obtained and analyzed in details. the receptor residues responsible for agonists/antagonists binding have been identified and mechanism of binding involving the highly conserved residues has been proposed. a three-dimensional models of the neurohypophyseal hormone receptors were constructed using a multiple sequence alignment and either the crystal structure of bovine rhodopsin or the complex of activated rhodopsin with gta c-terminal peptide of transducin rd*-gt(338-350) prototype to obtain nonactive or activated receptor models, respectively. analogs were docked to v1ar, v2r and otr, both non-active and activated models. the low-energy receptor-ligand complexes, with properly docked analogs were submitted to the constrained simulated annealing (csa), in vacuo. the relaxed receptoranalog models were obtained. the residues responsible for analogs binding to v1ar, v2r and otr have been identified and presumable biological activity of these compounds was determined. n-methyldehydroamino acids belong to non-standard amino acids found in nature. n-methyl-(z)-dehydrophenylalanine was found in tentoxin, a selective weed killer, having been produced by several phytopathogenic fungi of the alternaria genus. n-methyl-(z/e)-dehydrobutyrine and n-methyldehydroalanine are components of nodularins and microcystins, families of hepatoxins produced by species of freshwater cyanobacteria, primarily nodularia spumingena and microcystis aeruginosa. the simplest n-methyl dehydropeptides, ac-delta(me)xaa-nhme (where xaa = ala, (z/e)-abu, (z/e)-phe, and val) and, for comparison, the saturated ac-l-(me)ala-nhme analogue were investigated using computational methods. cis-trans b3lyp/6-31+g**//hf/3-21g ramachandran potential energy surfaces were created. the conformers found were optimised at the b3lyp/6-31+g** level. the effect of the electrostatic solute/solvent (water) interaction on the solute energies was investigated within the scrf method using the polarisable continuum model (pcm) on the geometries of solutes in vacuo. it was found that for all the studied dehydropeptide molecules the lowest conformer (phi, psi = ~ -109°, 10°) has the cis n-methyl amide bond. this feature seems to be independent of the dehydroamino acid moieties, the c-beta substituent and the z/e configuration. the pi-electron conjugation as well as the n-h···n hydrogen bond play the dominant role in the stability of this conformer (see figure) . the preliminary nmr investigations into the conformational preferences of the studied molecules in solution confirm the theoretical results obtained. the strong tendency of the n-methyl amide bond to adopt the cis configuration seems to be the reason why n-methyldehydroamino acids are found in small natural cyclic peptides, where they ensure the conformational flexibility necessary for biological action. the purpose of this study was to determine the potentials of mean force (pmf) of the interactions between models of nonpolar amino acid side chains in water. the potentials of mean force (pmf's) dependent on orientation were determined for systems forming hydrophobic and diagonal complexes composed of side-chain models of alanine, valine, leucine, proline and iso-leucine, respectively, in water. for each hydrophobic pair in water a series of umbrellasampling molecular dynamics simulations with the amber force field and explicit solvent (tip3p water model) were carried out and the pmfs were calculated by using the weighted histogram analysis method (wham). in all cases a characteristic shape of pmf plots for hydrophobic association were found, which was manifested as the presence of contact minima and solvent separated minima. depths of contact minima for all systems studied were about 1 kcal/mol. in this work we compared the ability of two theoretical methods of ph-dependent conformational calculations to reproduce experimental potentiometric-titration curves of two models of peptides: ac-k5-nhme in 95% methanol (meoh)/5% water (h2o) mixture and ac-xx(a)7oo-nh2 (xao) (where x is diaminobutyric acid, a is alanine, and o is ornithine) in water, methanol (meoh) and dimethylsulfoxide (dmso), respectively. in theory, in all three solvents, the first pka of xao is strongly downshifted compared to the value for the reference compounds, the water and methanol curves have one, and the dmso curve has two jumps characteristic of remarkable differences in the dissociation constants of acidic groups. the predicted titration curves of ac-k5-nhme are in good agreement with the experimental ones; better agreement is achieved with the md-based method. the titration curves of xao in methanol and dmso, calculated using the md-based approach, trace the shape of the experimental curves, reproducing the ph jump, while those calculated with the edmc-based approach, and the titration curve in water calculated using the md-based approach, have smooth shapes characteristic of the titration of weak multifunctional acids with small differences between the dissociation constants. quantitative agreement between theoretically predicted and experimental titration curves is not achieved in all three solvents. the poorer agreement obtained for water than for the nonaqueous solvents suggests a significant role of specific solvation in water, which cannot be accounted for by the mean-field solvation models m337 a. papakyriakou 1 , g.f. vlachopoulos 2 , g.a. spyroulias 2 , e. manessi-zoupa 3 , p. cordopatis 2 angiotensin-i converting enzyme (ace) belongs to the m2 family of the ma clan of zinc metallopeptidases and can act either as a dipeptidyl carboxypeptidase, which catalyses the proteolytic cleavage of dipeptides from the carboxy terminus of a wide variety of peptides, or as an endopeptidase, which hydrolyses peptides bearing amidated c-termini. among the former category of ace peptide substrates, the most distinguished are those involved in blood pressure regulation, such as angiotensin i (angi) and bradykinin (bk). in the latter category falls the gonadotropin-releasing hormone (gnrh) in an attempt to analyze molecular interactions at atomic level we simulated the ace-substrate complexes, using the recently determined 3d crystal structure of ace testis isoform and a knowledge-based docking method in order to insert the peptide substrate (angi, bk and gnrh) of ace into its catalytic cleft. in order to introduce the effect of protein mobility and gain information about enzyme-substrate recognition and interaction we have sampled the conformational space of these complexes via molecular dynamics simulations with explicit solvent representation. we have also performed molecular dynamics calculations with tace-inhibitor complexes, such as lisinopril, as well as with tace mutated at specific sites, such as the ligands of the two buried chloride ions that have been shown to affect substrate activity. our results provide new insights into the role of specific domains of tace and their implication in the enzyme activity, which is not readily apparent from the available crystal structures. two main mechanisms for the propagation of action potential in myocytes are: 1) the free flow of local circuit current through gap junctions and 2) the effect of electrical field. here we study effect of each mechanism and their importance during action potential propagation. method: we simulated the cardiac myocyte by the orcad software, then used the model of sinoatrial node to stimulate the myocytes model and studied the propagation of action potential with and without gap junction. result: our results show that, although gap junction solely is not able to mimic physiological condition, but it is necessary for normal cardiac functioning. on the other hand, electric field is not sufficient for successful propagation of action potential and the existence of gap junction is necessary. anthrax is a disease of animals and humans, caused by the bacterium bacillus anthracis. anthrax toxin (at) consists of three proteins, one of which is the anthrax lethal factor (alf). alf is a gluzincin zn-dependent highly specific metalloprotease (~90.000 kda), which belongs to the m34 family of the ma clan of zinc metalloproteases. alf cleaves most isoforms of mitogen-activated protein kinase (mapk)-kinases (meks) close to their amino termini, leading to the inhibition of one or more signaling pathways. no data are available on the enzyme-substrate interaction at the molecular level. therefore, we performed classical molecular dynamics simulations on the alf-mkk/mek complexes in order to probe protein-substrate interactions. the simulations pinpointed specific hydrophobic as well as electrostatic alf-peptide substrate interactions and these data were exploited in the building of virtual combinatorial libraries of di-and tri-peptides using the twenty native aminoacids. by applying docking simulations to anthrax zn-metalloprotease around 1.000 peptide substrates were virtually screened according to their binding affinity. data suggest that complexes of alf with peptides substrates bearing arg, trp, lys and phe aminoacids, exhibit the highest binding affinity providing evidence for electrostatic interactions between negatively charged residues of alf's active site and positively charged side-chains of di/tri-peptides. new libraries of substrates were built incorporating non-protein residues, organic moieties and chelating groups. alf-substrate complexes with the best score (in terms of binding energy) are further analysed. in the present studies we designed and synthesised seven new bradykinin (bk) analogues and evaluated them in the in vivo rat uterotonic assay using a modified holton method in munsick solution on a strip of rat uterus and in blood pressure test. we used [arg0, hyp3, thi5, 8, d-phe7]bk, the b2 antagonist of vavrek and stewart as a model, when designing our analogues. in all cases, the n-terminus of our peptides is acylated with bulky substituent. we previously reported that acylation of the n-terminus of several known b2 antagonists with various kinds of bulky acyl groups has consistently improved their antagonistic potency in rat blood pressure assay. on the other hand, our earlier results seem to suggest that effects of acylation on the contractility of isolated rat uterus depend substantially on the chemical character and size of the acyl group, as we observed that this modification may either change the range of antagonism or even transform it into agonism. the peptides were synthesized by the solid-phase method using the fmoc-strategy the modifications proposed either preserved or increased the antagonistic potency in the rat blood pressure test. on the other hand, the seven substituents, differently influencend the interaction with the rat uterine receptors and except one led to decrease of antiuterotonic activity. in both cases acylation of the n-terminus led to enhancement of antagonistic potencies. our results may be of value in the design of new b2 agonists and antagonists. the formations of amyloid fibrils have been reported as for various amyloidosis. several structural models of fibrils are proposed for respective proteins so far. however, their common basic structures and universal features to induce amyloid fibril formations are not known in detail. previously, we examined intermolecular interactions among the several amino acid residues in barnase, which is known to form amyloid-like fibril. based on the experimental results using a series of mutant barnase, we discovered that the interactions between hydrophobic side-chains are the most essential driving force to form the fibrils and that both intermolecular and inter-sheet interactions in the fibril maintain highly ordered molecular packing. in the present paper, we describe a novel prediction method for core regions of various fibril-forming proteins and show the verification of the above possible structural principle. at first, we calculated the interaction's score between side-chains in the antiparallel orientation of beta-strands. next, the peptides with predicted sequences of fibril cores, a couple of high-scored regions with a designed turn moiety to induce a hairpin-like form, were chemically synthesized by spps. as a result, the formation of amyloid fibrils was confirmed for most of high-scored sequences. in addition, we also applied this method to prion protein, we could predict 4 possible beta-strands with hetero-paired orientation. some synthetic peptides involving these strands were proved to have fibril-forming ability. thus, we have developed the novel method to predict the core regions that induce amyloid fibrils. a principal factor analysis (pfa) is a very efficient way of identifying patterns in the data sets even if the patterns are hard to find (e.g. in the high dimensional data sets). this is the reason why the pfa method can be powerful tool for analyzing molecular dynamics (md) trajectories. it is possible to reduce dramatically the trajectory size without loosing significant structural information by applying the pfa procedure. we used this tool for interpretation of results from the molecular dynamics simulations of the model of the transcription factor nf-kb. nf-kb is a protein involved in the numerous biological processes such as regulation of immune response, inflammation, various autoimmune diseases and is used by many viruses, including human immunodeficiency virus (hiv), to activate transcription of their own genes. only the trajectory of the backbone atoms of the nf-kb were subjected to the further analysis. peptides contain many basic sites such as side chains of basic amino acid residues, oxygen and nitrogen atoms of amide groups, and terminal amino groups. these parts can interact with protons. this interaction can change conformational behaviour of peptides and, consequently, their biological functions. the interaction becomes even stronger in the gas phase. in that case, the stability of the peptide chain is influenced, which may have impact on peptide fragmentation during mass spectroscopy analysis of peptide structures. in this study, we will present the interaction of proton with carbonyl oxygens in the model of alanine tripeptide. quantum chemical calculations employing density functional theory using hybrid b3lyp functional and 6-31++g** basis set were used to describe this interaction and also to find possible pathways of proton transfer among interaction sites. two different mechanisms of proton transfer were found. the first mechanism is represented by an isomerization of the proton around the double bond of the carbonyl group. the second mechanism is based on the large conformational flexibility of the tripeptide model where all carbonyl oxygens cooperate. the later mechanism exhibits nearly half energy barrier of the rate-determining step compared to the first one. we focus our attention on situation, in which methyl groups attached to alpha atoms in tripepetide model influence the conformational behavior. results will be presented for all four possible stereochemical configurations. a. papakyriakou 1 , p. galanakis 2 , p. gazonis 2 , g.a. spyroulias 2 p53 protein is one of the most effective defensive weapons of human body against carcinogenesis, due to its tumor suppression properties. it has been noticed, in many types of cancer, that the functions of p53 are being downgraded or even suppressed and this fact is ought to the presence of mutated forms of p53 or to the complete absence of the protein. the suppression of p53 levels is being indirectly regulated by the protein itself, which activates the expression of a gene, the oncogene mdm2 (murine double minute 2), which expresses the mdm2 protein, known as human-mdm2 or just hdm2. hdmx protein is a homologue protein to hdm2 and is being implicated, through various biological processes, in the suppression of p53. however, recent experimental evidence suggests that hdm2 and hdmx proteins are not the only ubiquitin ligases that negatively regulate p53 through ubiquitin pathway. two recently discovered e3 ligases, cop1 and pirh2, are also proposed to promote p53 for degradation. all these proteins function as e3 ligases bearing a ring finger domain. these domains are characterized by their high content in cysteines and the binding of two zn(ii) ions while they catalyze the latter stage of protein signaling for proteolysis by the 26s proteasome, through the ubiquitin pathway. the structure variation and the stability of these ring fingers is studied through molecular dynamics simulations of 2-5 ns and structure variations are analyzed in a structure-function correlation basis. semax is a synthetic analogue of adrenocorticotropic hormone acth 4-10. it is a nootropic agent containing seven amino acids met-glu -his-phe-pro-gly-pro without hormonal (adrenocorticotrophic) activity. semax is neuroprotective via a mechanism involving the regulation nitric oxide (no) and lipid peroxidation. semax proved to be highly effective in abating the rise in no and restoring neurologic functioning [1] . it was found to improve intellect and memory in healthy human. it is effective in rehabilitation of people with memory and motor disorders, parkinson's and hantington's diseases, after cerebral stroke and head trauma [2] . to study conformation dynamics in connection with in vivo activity of semax the molecular dynamics method of standard protocol was applied [3] . semax and about twenty its analogs were studied. using cluster analysis method semax was found to be more labile among various synthesized analogous (met-gln -his-phe-pro-gly-pro; gly-glu-his-phe-pro-gly-pro; lys-glu-his-phe-pro-gly-pro; glu-his-phe-pro-gly-pro; his-phe-pro-gly-pro). because of collective degree of freedom it has one more stable configuration that is unreachable in analogs. singularities of semax and analogous were studied using 2-d, 3-d poincare maps, auto and crosscorrelation functions of special type in terms of topological structure of energy hypersurface. this work was supported by rfbr (pr. 04-04-49645), russian ministry of education and science, moscow government and crdf. rhodopsin (rd) is the only representative of g-protein coupled receptors (gpcrs) whose structure has been described with high resolution. thus, it has become the structural prototype for other gpcr. these receptors are involved in transduction of various signals into the cell and actions of many hormones and neurotransmitters. about 50% of all drugs act through gpcr. growing evidence that rd and related gpcrs form functional dimers/oligomers, followed by direct proof (using atomic force microscopy -afm) that in the retina rd associates into a paracristalline network of rows of dimers, need models of rd-transducin (g t -heterotrimeric protein) complex that would envision an optimal rd dimer/oligomer amenable to satisfy all well documented interactions with gt. current model includes tetramer built of two activated (metaii) and two inactive rd molecules, ligands stabilising metaii: gtα(ile338-phe350) and gtγ(asp60-cys71)farnezy, lipid bilayer built of 36 pc (phosphatidylocholin head groups) , 6 ps (phosphatidyloserine) and 30 pe (phosphatidyloetanolamine) (all three types of phospholipids contain the polyunsaturated docosahexaenoyl chain -dha) and water. experimental data concerning shape of oligomer, conformational changes in metaii, proper interactions and distances among residues have been looked upon. the poster shows results of the molecular dynamic carried in amber force field for ~6000ps in the periodic box. conformational changes which took place during simulation caused proper adaptation one another monomers in tetramer and ligands to activated receptors. the human cystatin c (hcc) is a one of known domain swapping proteins. during this process, one of the hcc β-hairpins (β2-l1-β3) changes its conformation forming long β-strand. this conformational transition destabilizes the monomer structure and leads to domain-swapped dimer. the causative force for changing the βhairpin conformation is assumed to be the alleviation of distortions of the l1-loop val57 amino acid residue's backbone. following the above assumption and our previous conformational studies of the hcc β-hairpin peptide we investigated the influence of the point mutations, v57d, v57p and v57n of the val57 residue, on the β-hairpin peptide structure. the conformational studies by means of cd spectroscopy and molecular dynamics studies were performed. the study revealed that the hcc peptide with the wild-type sequence has the strongest tendency from all studied peptides to form a β-hairpin structure. on the basis of these results we conclude that the presence of distortions in the val residue of l1-loop is unlikely to cause the 3d domain swapping of the human cystatin c. acknowledgments: this work was financially supported by the ministry of scientific research and information technology of poland under grant 1t09a10430. temporin a (ta) (flpligrvlsgil-nh2) and temporin l (tl) (fvqwfskflgril-nh2 ) are small, basic, hydrophobic, linear antimicrobial peptides amide found in the skin of the european red frog, rana temporaria. these peptides have variable antibiotic activities against a broad spectrum of microorganisms, including clinically important methicillin-sensitive and resistant staphylococcus aureus as well as vancomycin-resistant enterococcus faecium strains. to gain further insight into the mechanism of action of these small antimicrobial peptides, we have investigated their conformational behaviour in different environmental conditions. more specifically, we deeply investigated by solution nmr spectroscopy in water and water/dmso (8:2) solutions as isotropic solutions and 200 mm aqueous solution of dpc (dodecylphosphocholine) was used as membrane mimetic environment. understanding the basis of the interactions of temporins with membranes could be crucial for the design and synthesis of potent antimicrobial agents. cripto is the founding member of a family of soluble and cell bound growth factors known as egf-cfc [1] distinguished by the presence of an n-terminal signal peptide, two distinct cysteine-rich domains (crd) and a c-terminal hydrophobic region involved in cell surface attachment by a post-translational gpi modification. the characteristic crds, known as egf-like and cfc domains (from the first members cripto, frl1 and cryptic), both span about 40 residues with 3 disulfide bridges [2] each, which, presumably, beside a possible functional modularity, confer them also a structural independence. in this work we have focused our attention on the cfc domain of mouse cripto. the domain has been produced by ssps, along with variants bearing mutation on h104 and w107, that have been described as crucial for alk4 receptor recognition. the two variants have been purified and refolded, achieving the correct disulfide bridges, and then comparatively analyzed by cd spectroscopy under different ph conditions; thus obtaining experimental insights on the structural arrangements of this new class of protein domains. furthermore, the binding properties of wild type and mutants cfc domains to alk4 receptor have been determined by using an elisa-based assay. our results demonstrated that the cfc domain alone can directly bind alk4 in the absence of additional ligands and, furthermore, confirmed a role of h104/w107 in cripto/alk4 interaction. there is considerable interest in the pharmacology of the two cholecystokinin (cck) receptors ccka-r (or cck-1) and cckb-r (or cck-2) that mediate the biological action of the cck hormone. they are membrane receptors belonging to the superfamily of g-protein coupled receptors (gcpr) and are predominantly located in the gastrointestinal tract and in the central nervous system, respectively. a library of 14 cyclic peptide analogues derived from the octapeptide c-terminus sequence of the human cholecystokinin hormone [cck(26-33), or cck8] has been designed, synthesised and characterised. the 14 peptide analogues have been rationally designed to specifically interact with the cck type b receptor (cckb-r) on the basis of the structure [2] of the bimolecular complex between cck8 and the third extracellular loop of cckb-r [namely, cckb-r(352-379)]. the new ligands showed binding affinities generally lower than that of parent cck8. anyway, structure activity relationship data underline that preservation of the trp30-met31 motif is essential, and that the phe33 side chain and a carboxylic group close to the c-terminal end must both be present. the nmr conformational study in dpc micelles of the compound endowed with maximal binding affinity (cyclo-b11, ic50=11 m) shows that this compound presents the turn-like conformation, centred at the trp30-met31 segment, as planned by rational design, and that such conformation is stabilised both by the cyclic constrain and interaction with the micelle. cripto is the founding member of a family of extracellular growth factors called egf-cfc found in mouse, human, chicken, xenopous and zebrafish [1] . these proteins are characterized by the presence of an n-terminal signal peptide, a c-terminal hydrophobic region and two highly conserved cysteine-rich domains, the egf-like (epidermal growth factor) and the cfc (cripto/frl1/cryptic). cripto is strictly required in the early embryonic development and contributes to deregulated growth of cancer cells in adults, since it is highly over-expressed in many solid carcinomas. it has been proposed that each single domain of cripto could bind different protein partners, playing different functional roles [2] . on this grounds, investigation of the single domains 3d-structures can have also strong functional implications. we present here an extensive conformational analysis of the mouse cfc domain (96-134 sequence) and of the w107a mutant based on nmr data. sequences have been synthesized by spps and refolded reconstituting the correct disulfide bridges [3] . the molecular models have been built by computational methods using the nmr data collected under both acidic (ph 3) and nearly physiological (ph 6) conditions. both domains show a globally extended folding with three strands linked by the three disulfide bridges and two connecting loops, in which h104 and w107, key residues in receptor binding, are exposed to the solvent urantide, a selective antagonist. thus, we carried out a study aiming at the characterization of conformational arrangement and affinity properties of ut extracellular segments.we measured by surface plasmon resonance (spr) technology the binding affinities of the three ligands, u-ii, urp and urantide towards the three extracellular loops of ut. furthermore, the secondary structures of the synthetic receptor fragments in presence of dodecylphosphocholine micelles and interaction with ut ligands were analysed using nmr spectroscopy. spr data showed that the ec loop ii was able to recognize the ligands u-ii, urp and urantide with similar affinities while none of these two ligands were able to interact with the extracellular loop i. furthermore, the absence of binding of urantide, a peptide antagonist, suggested strongly that loop iii would be involved in the signal transduction process and implies that u-ii and urp, but not urantide, would bind to ut according to a common pattern. moreover, the results indicate that potent ut antagonists could be designed by producing highaffinity ligand targeting the extracellular loop ii. also, the spr and nmr studies revealed that the synthetic structural ut domains contained some of the conformational and chemical features essential for the binding of hu-ii, urp and urantide to hut. synthetic cysteine-rich replicates of naturally occurring peptides such as hormones, neurotransmitters, enzyme inhibitors, defensins and toxins often can be oxidatively folded in high yields to their native structure. the presence of identical cysteine patterns in the sequence were found to lead to identical disulfide connectivities and homologous spatial structures despite significant variability in the non-cysteine positions. therefore, it is generally accepted to attribute the disulfide connectivities based on the homology of their cysteine pattern. minicollagen-1 from the nematocysts of hydra is a trimeric protein containing n-and c-terminal cysteine-rich domains involved in the assembly of an intermolecular disulfide network. examination of three-dimensional structures of peptides corresponding to these folded domains by nmr spectroscopy revealed a remarkable exception from the general admitted rule [1] . despite an identical cysteine pattern, they form different disulfide bridges and exhibit distinctly different folds. additionally, comparative analysis of the oxidative folding revealed for the c-terminal domain a fast and highly cooperative formation of a single disulfide isomer, the n-terminal domain proceeding mainly via an intermediate that results from the fast quasi-stochastic disulfide formation according to the proximity rule. to our knowledge, this is the first case where two short peptides with identical cysteine pattern fold uniquely and with high yields into defined, but differing, structures. therefore, these cysteine-rich domains may well represent ideal targets for structure calculations to learn more about the elementary information encoded in such primordial molecules. the conformational change of the cellular prion protein, prpc, to its virulent "scrapie" form, prpsc, is believed to be responsible for prion infectivity. and several studies suggest that the prion disulfide bond is important for the stability, structure, and propagation of prion oligomers. to test this hypothesis, we selected two conserved peptides flanking the disulfide bond in the sheep prion protein, and measured the secondary structure of these peptides with circular dichroism, hydrogen/deuterium exchange, and molecular dynamics simulations. our preliminary data suggests that the two peptides do not adopt stable secondary structure, native or otherwise. thus, the folding intermediate of a prion protein seems unlikely to comprise local structure around the disulfide bond. the conformationally labile cα-tetrasubstituted α-amino acid residue bip possesses non isolable (r) and (s) atropoisomers. we have previously reported that in the linear dipeptides boc-bip-α-xaa*-ome with α-xaa* = ala, val, leu, phe, (αme)val and (αme)leu residues at the c-terminal position of bip, the onset of an equilibrium between diastereomeric conformers with unequal populations could be observed by cd and 1h nmr. the phenomenon of induced circular dichroism (icd) represents the basis for the "bip method", an easy and fast configurational assignment for chiral α-amino acids. in search for an extension of the bip method, we investigated the boc-bip-β-xaa*-ome dipeptide series with β-xaa* = β3-hala, β3-hval, β3-hleu, β3-hpro, β3-hphe, or the cyclic β2,3-amino acids (1s,2s)/(1r,2r)-achc and (1s,2s)/(1r,2r)-acpc. low-temperature (233 k) 1h nmr spectra in cd3od revealed the presence of two conformers. significant d.r. (diastereomeric ratio) values were observed for all combinations of bip with both β3-and cyclic β2,3-amino acids. cd analysis in meoh solution of the boc-bip-β-xaa*-ome dipeptides allowed us to conclude that the cd resulting from the induced axial chirality in the biphenyl core of the bip residue gives clear information on the β-xaa* configuration for both β3-and cyclic β2,3-amino acids (except the aromatic β3-hphe), with a p torsion of the biphenyl axial bond of bip being preferentially induced by (l)-β3-xaa* as well as cyclic (1s,2s)-β2,3-xaa* c-terminal residues. we have recently reported that the induced circular dichroism (icd) of the biphenyl core of boc-bip-xaa*-ome dipeptides based on the conformationally labile cαtetrasubstituted α-amino acid residue bip could allow an easy and fast configurational assignment for both α-and β-xaa* amino acid residues. in search for other biphenyl/xaa* architectures in which a transfer of central to axial chirality could result in a potentially useful icd, we considered n-substituted 6,7-dihydro-5hdibenz[c,e]azepine (daz) derivatives from α-and β-amino acids as interesting candidates. in the present communication, we report the syntheses, and the 1h nmr and cd analyses of a series of (daz)xaa*-ome amino esters derived from α-, β3-, and cyclic β2,3-xaa* residues, namely dβ-peptide molecules possess interesting conformational characteristics and biological properties. they may represent a new class of rigid foldamers potentially useful as templates or spacers. 3d-structures of β-peptides have been experimentally investigated using x-ray diffraction and various spectroscopic techniques, but they have never been doubly spin labelled and studied by epr. a terminally protected β-hexapeptide, based on trans-(3r,4s)-β-toac and trans-(1s,2s)-achc, synthesized using classical solution methods, was found by ft-ir absorption and cd techniques to adopt the 3-14-helical conformation. a set of four, terminally blocked, hexapeptide sequences, each characterized by four strongly helicogenic aib residues and all combinations of the two isomeric ile/allo-ile residues at positions 2 and 5 was synthesized by solution methods and fully characterized. a detailed solution (by ft-ir absorption, nmr, and cd) and solid (crystalline)-state (by cd and x-ray diffraction) conformational investigation allowed us to validate our assumption that all four peptides are folded in well developed 3-10-helical structures. however, the most relevant conformational conclusion extracted from this 3d-analysis is that the handedness of the 3-10-helical structures formed does not seem to be sensitive to the configurational change at the β-carbon atom of the constituent ile versus the diastereomeric allo-ile residues (in other words, the dominant control on this important structural parameter appears to be exerted by the chirality of the amino acid α-carbon atom). these results complement published findings on the diverging relative stabilities of the intermolecularly h-bonded β-sheet structures generated by ile versus allo-ile homo-oligopeptides. taken together, these data represent an experimental proof for the intuitive view that potentially different conformational properties are magnified in a strongly self-aggregated homo-peptide system (as compared to weakly self-aggregated, helical, host-guest peptides such as those investigated in this work). in a first approach to β-sandwich proteins the hydrophobic core between two symmetrical sheets each with four antiparallel β-strands was computationally designed by packing of amino acid side chain conformations (rotamers) in an initially given backbone structure. the proteins were synthesized by coupling four peptides with β-hairpin structure to a cyclic decapeptide template (tasp). an aggregation observed by equilibrium ultracentrifugation with the first designed proteins was decreased to a dimer by increasing the surface charge in two further variants of this protein from -1 to +3 and +5. replacement of l-pro by d-pro in the loops and the template proved to stabilize the β-structure. these results led us to an improved design of an asymmetric core with algorithms for selection of proteins with a minimal number of atom clashes and cavities in the core, and a maximum number of hydrogen bonds after energy minimization. this protein termed beta-mop (modular organized protein) was synthesized in amounts to allow a characterization by cd, ftir, tryptophan fluorescence during reversible unfolding, and by high resolution nmr. nmr measurements of diffusion indicate a dimeric structure. the β-structure is stable up to 80 °c (353 k) as determined by 1d 1h nmr showing sharp resonance lines. the 2d 1h,1h dqf-cosy spectrum at 750 mhz shows a typical βsheet distribution extending well into the characteristic regions >8.5 ppm (for amide protons) and >5.0 ppm (for hα signals). all data indicate a well folded protein with β-structure. a.s. galanis 1 , z. spyranti 1 , n. tsami 1 , g.a. spyroulias 1 , e. manessi-zoupa 2 , g. pairas 1 , i.p. gerothanassis 3 , p. cordopatis 1 angiotensin-i converting enzyme (ace) belongs to the m2 family of the ma clan of zinc metallopeptidases and can act either as a dipeptidyl carboxypeptidase, or as an endopeptidase. among the ace peptide substrates, the most distinguished are angiotensin i (angi) and bradykinin (bk) due to their role in blood pressure regulation. despite the fact that biological data strongly suggest that the two active sites exhibit different selectivity and activity towards physiological and exogeneous substrates none experimental evidence for the interaction of angi and bk with ace catalytic sites, is available so far. a dual approach for studying the structure and physicochemical determinants of ace-angi/bk interaction has been performed. the first involves the application of molecular dynamics simulations (presented elsewhere in this book) and the second is making use of the solid-phase synthesized 36-46 aa ace catalytic site maquettes (csm) bearing the native sequence and the application of the nmr spectroscopy, and presented herein. therefore, high-resolution multinuclear nmr spectroscopy was applied to analyze the conformational features of ace substrates angi and bk in dmso or aqueous mixtures. then titration experiments were conducted and ace csms were titrated by angi/bk peptides, while monitored by nmr. 2d 1h-1h tocsy and noesy experiments were used in order to map the interaction site of both substrates and csm through chemical shift perturbation and comparison of noe signal differentiation. competitive binding studies were also carried out through titration studies of csm-angi/bk and known ace inhibitors. a. carotenuto 1 , p. grieco 1 , l. auriemma 1 , e. novellino 1 , v.j. hruby 2 the melanocortine receptors are involved in many physiological functions, including pigmentation, sexual function, feeding behavior, and energy homeostasis, making them potential targets to treat obesity, sexual dysfunction, etc. understanding the conformational basis of the receptor-ligand interactions is crucial for the design of potent and selective ligands for these receptors. the conformational preferences of the cyclic melanocortin agonists and antagonists mtii, shu9119, [pro6]mtii, and pg911 (table 1) when two chromophores are chirally oriented and close enough to one another in space, their excited states couple and become non-degenerate. this phenomenon, termed exciton coupling, produces a typical bisignate cd curve. the intensity of the cd couplet is dependent on the molar extinction coefficient and the distance between the interacting chromophoric moieties, while the sign is governed by the angle between the effective electron transition moments. in particular, exciton coupling over a long distance can be observed only with strongly absorbing chromophores, e. g. porphyrin derivatives, characterized by their extremely intense and sharp soret band near 415 nm. in this work we examined by the exciton coupled cd method the combined distance and angular dependencies, generated by the seven conformationally restricted β-turn and 3-10-helical spacer peptides -l-ala-[l-(αme)val]n-(n = 1-7) on a system formed by two intramolecularly interacting 5-carbamido-5,10,15,20-tetraphenylporphyrin chromophores. these porphyrin derivatives are confirmed to be excellent reporter groups. we find that not only the centerto-center separation (from 19 to 34 å) between the two chromophores, but the orientation (roughly parallel or perpendicular) between the directions of their effective transition moments as well, are responsible for the onset or even for the modulation of the intensity of the exciton coupling phenomenon. in particular, the porphyrin…porphyrin interaction is still clearly detectable over the long distance of ca. 30 å when the two chromophores are about perpendicularly oriented. a. hetényi 1 , g.k. tóth 2 , c. somlai 2 , t.a. martinek 1 , f. fülöp 1 β-peptides are probably the most thoroughly investigated peptidomimetic oligomers. to extend the field of β-peptides towards the construction of possible new secondary structures, the replacement of the cα and cβ atoms of the β-amino acid with heteroatoms could be an attractive modification, for example cβ-atom of β-peptides by an nr moiety, leading to hydrazine peptides. in the literature, there are only a few studies [1] [2] [3] about hydrazine peptides, and hydrazine peptides with cyclic side-chain have not been studied yet. in order to determine the secondary structure preference of 1-amino-pyrrolidine-2s-carboxylic acid homo-oligomers (figure 1 ), their potential energy hypersurface were probed at the ab initio b3lyp/6-311g** level. the calculations predicted the 8-strand to be the most stable structure. the hydrazino-peptides in question were synthetized on solid support, and their structures were characterized by nmr and cd methods. the results were found to be in good accordance with the 8-strand structure. cathepsin c [ec 3.4.14.1](1), which belongs to family of cysteine proteases, catalyzes hydrolysis of n-terminal peptide, preferential glyphe. this enzyme may play a part in chronic airway diseases (2) . also increaser level of enzyme was found in case of cancer, rheumatism and muscle's distrophy (3) (4) (5) . for this reason we have undertook investigations of peptides containing two dehydroamino acid residues, which could act as alkylating inhibitors of this enzyme. to define structure and conformation of investigated peptides we were used different methods of nmr spectroscopy, including standard 1d experiments, protonproton correlations, proton-carbon correlations, and 2d noe experiments. to complete structural research computational chemistry methods had been used. in order to predict the biological activity of investigated peptides, the simulation of docking process of these peptides to enzyme active site had been made and after that correlated with results of enzymatic test.. the obtained results suggest, that investigated peptides containing two ∆phe residues (z and e isomers respectively) in solution have bent conformation, which is stabilized by intermolecular hydrogen bonds. these results are confirmed by the results of theoretical calculations. also simulation of docking process have showed two possible peptide's orientation in active site of cathepsin c and allowed the rational interpretation of biological test's results. turns are important elements of secondary structure in peptides and proteins. different types of turns are distinguished according to the number of residues involved. the most abundant is the β-turn, which involves four consecutive amino acids with the co at position i hydrogen-bonded to the i+3 nh. the γ-turn is centred at a single residue and is generally stabilized by a hydrogen bond between the i co and the i+2 nh. model dipeptides rco-l-pro-xaa-nhr' are the smallest systems able to adopt the β-turn conformation, which is favoured by the presence of proline at i+1. a peptide of this series, incorporating a cyclopropane amino acid (xaa), has been shown to accommodate two consecutive γ-turns in the solid state [1] , instead of the expected β-turn conformation. the double γ-turn encountered is unique among crystalline short linear peptides. in fact, the γ-turn is observed almost exclusively in low-polarity solvents, and only a few oligopeptides of cyclic structure exhibit a γ-turn in the crystal. this is the first time that the strong tendency of pro-xaa dipeptides to adopt a β-turn in the solid state has been switched to the γ-turn. theoretical calculations [2] also show the high preference of this cyclopropane amino acid for the γ-turn conformation. [ oxidative stress plays an important part in the development of cardiovascular disease (cvd). haptoglobin is a hemoglobin-binding protein that has a major role in providing protection against heme-driven oxidative stress. there are two common alleles for haptoglobin (1 and 2), and the three phenotypes, haptoglobin 1-1, haptoglobin 2-1, and haptoglobin 2-2, differ in their ability to function as antioxidants. we determined whether there was a relation between the haptoglobin phenotype and the development of coronary artery diseases. haptoglobin (hp) phenotypes were determined in iranian patients with coronary artery diseases. we performed haptoglobin (hp) genotyping by polymerase chain reaction (pcr) using allele-specific primer-pairs. in multivariate analyses controlling for conventional cvd risk factors, haptoglobin phenotype was a highly statistically significant, independent predictor of cvd. the odds ratio of having cvd in patients with the haptoglobin 2-2 phenotype was 5.0 times greater than in patients with the haptoglobin 1-1 phenotype. an intermediate risk of cvd was associated with the haptoglobin 2-1 phenotype. these results suggest that haptoglobin phenotype is an important risk factor in determining susceptibility to cardiovascular disease which may be mediated by the decreased antioxidant and antiinflammatory actions of the haptoglobin 2 allelic protein product. the special feature of proteins involved in alzheimer's or prion diseases is their ability to adopt at least two different stable conformations. the conformational transition that shifts the equilibrium from the functional to the pathological isoform can happen sporadically. it can also be triggered by mutations in the primary structure, changes of different environmental conditions, or the action of chaperones. elucidation of the molecular interactions that occur during the transformation from α-helix to β-sheet and the consecutive formation of amyloids on a molecular level is still a challenge. therefore, the development of small peptide models that can serve as tools for such studies is of paramount importance. we succeeded in generating model peptides that, without changes in their primary structure, predictably react on changes of diverse environmental parameters by adopting different defined secondary structures. these de novo designed peptides strictly follow the characteristic heptad repeat of the α-helical coiled coil structural motif. furthermore, domains that favour β-sheet formation and aggregation can be generated.1 alternatively, those peptides can be equipped with functionalities that allow either the binding of metal ions or the interaction with membranes. as proof of our concept we showed that the resulting secondary structure of such peptides will strongly depend on environmental parameters. thus, this system allows to systematically study the interplay between peptide / protein primary structure and environmental factors for peptide and protein folding on a molecular level. the pathogenesis of alzheimer's disease (ad) is strongly linked to neurotoxic assemblies of the amyloid β protein (aβ). aβ is a soluble component of human plasma which by an unknown mechanism becomes aggregated and neurotoxic. some genetic mutations within the aβ sequence cause very early onset of ad-like diseases, probably by facilitation of aβ assembly into neurotoxic species. recently, it was found that not amyloid fibrils, but smaller aβ assemblies initiate a pathogenic cascade resulting in ad. therefore, preventing the folding of nascent aβ monomers would have therapeutic benefit. to uncover details of structural changes accompanying the aggregation process, especially its initial stage, we have decided to study the aβ(11-28) fragment and its mutation-related variants. our recent studies on this aβ fragment using the cd method and the aggregation test have proved it a good model for structural studies. the obtained results confirmed that the aggregation process follows the scheme with an α-helical intermediate and pointed out differences in the behaviour of aβ variants. to further confirm the scheme of the structural changes accompanying aggregation we have applied ftir spectroscopy and analysed aggregation-induced changes of the amide i band which is directly related to peptide backbone conformations. the ftir spectra analysis indicate that water addition provoked conformational changes are strongly dependent on the aβ(11-28) variant and in some cases the formation of α-helical intermediate seems to be preceded by 310 helix formation. to verify this hypothesis the temperature dependent atr ftir spectra will be analysed. supported by ug bw grant. amino acid octarepeats present in the prion protein bind to cu2+ and are considered as a potential periplasmic copper ion transporters. this octarepeat is located in the unstructured region of the prion protein, which is supposedly not intricately involved in prion aggregation. our group is involved in exploring the function of octarepeats with a special emphasis on their possible role in amyloid fibril formation and aggregation.1 in this context, we have prepared truncated peptide constructs derived from the prion protein octarepeat phgggwgq and have reported their fibrillation activity. we will present aggregative behavior of a truncated bis-pentapeptide, containing gggwg segment, when tethered with a flexible linker diaminobutane. fibrillar architectures were observed by this bis conjugate after incubation in water which was probed by different microscopic and steady state fluorescence techniques. further investigations with ki revealed a homogeneous environment of the two tryptophan moieties in the conjugate. in the absence of other side-chains, it is likely that fibril formation involves hydrophobic interaction between tryptophan indole moieties and main chain backbone interactions. interestingly, a facilitator role for aromatic-glycine motifs for amyloid aggregation has been proposed based on bioinformatics search of the swiss-prot and trembl databases. collagens are known to fold into a highly ordered rode-shaped triple helix with stretches of lower and higher suprastructural stability and even disruptions to modulate recognition by other proteins that interact with the extracellular matrix [1] . to increase understanding of folding and stability of the collagen triple helix, we have adressed the design of photocontrolled collagenous peptides. our aim was to crosslink two side chains of the repetitive (xaa-yaa-gly) sequence motifs of collagen model compounds via an azobenzene chromophore in analogy to our previous studies on photomodulation of the conformational preferences of cyclic peptides and more recently of hairpin-peptide model systems [2] . molecular modeling experiments suggested appropriate sequence positions that could result in triple-helical peptides with conformational stabilities that can be modulated by cis/trans isomerization of the azobenzene moieties. as light switchable crosslinker azobenzene-4,4'-n-(4-iodo-2-butynenyl)carboxyamide was synthesized for reaction with two (4s)-mercaptoproline residues placed in suitable xaa and yaa positions, respectively. by this approach a fully folded triple helix was obtained upon thermal relaxation, and unfolding was induced by irradiation at 350 nm. the favorable optical properties of the azobenzene derivative together with the regular suprastructure resulted in a valuable model system that allows for ultrafast time-resolved studies of collagen folding and unfolding. amyloid formation is connected with alzheimer's disease, parkinson's disease, finnish familial amyloidosis. after protein misfolding short peptide sequences act as "hot spots" providing the driving force for protein aggregation in amyloid fibrils. we have identified one of these sequence stretches in the abl-sh3 domain of drosophila (dlsfmkge) whereas the human homologous region (dlsfkkge) is predicted to be less amyloidogenic. the possible reason for the difference of amyloid formation propensities of the two peptides was investigated by molecular dynamics (md) of β-sheet structures. the antiparallel alanine β-sheets consisting of two and ten strands were constructed, minimized, and mutated to the sequences dlsfmkge and dlsfkkge. all four systems: 1) dlsfmkge -two strands, 2) dlsfkkge -two strands, 3) dlsfmkge -ten strands, 4) dlsfkkge -ten strands, were surrounded by 10 å layer of water molecules over the solute and subjected to md, amber 8.0 force field, ntp protocol. the md runs were started at the temperature of 10 k and the temperature was elevated stepwise by 10 degrees till 300 k. the results show considerably higher hydrogen bond percentage for dlsfmkge than that one for dlsfkkge during the course of the simulation, thus suggesting that dlsfmkge is a potential fibril-maker, but dlsfkkge is not. two strand β-sheet systems were stable until 170 k. the ten strand β-sheets are more stable. angiotensin-i converting enzyme (ace) has a critical role in cardiovascular function, which consists of cleaving the carboxy terminal his-leu dipeptide from angiotensin-i producing a potent vasopressor octapeptide, angiotensin-ii. there are two isoforms of ace. the somatic isoform is present in all human cells except the testis cells, where the testicular isoform is produced. the major difference between these two types is that, the somatic form has two active sites, at the n-and c-end respectively while the testicular has only one, which is almost identical to the somatic c-terminal active site. here we report the structural study of a 108aa peptide (previously expressed in bacteria), which corresponds to an extended domain of the human somatic n-terminal active site of ace (ala361-gly468) by circular dichroism experiments, and the overexpression in bacteria, purification and structural study, using circular dichroism techniques, of a 108aa peptide which corresponds to an extended domain of the human somatic c-terminal active site of ace (ala958-gly1065). following the subclonning into an appropriate expression vector and the expression, the peptide was isolated from the inclusion bodies using chromatography techniques. the recombinant protein fragment had a molecular weight, measured by esi-ms, of 12102 kda which was in consistence with the theoretical calculation based on the dna sequence. the recombinant peptides acquired their theoretically calculated secondary structure only when 1,1,1-trifluoroethanol is present at a concentration of ~70%. in order to elucidate their structures, solutions of these peptides, labeled with 15n and/or 13c, will be studied by nmr spectroscopy. aggregation of peptides is believed to trigger various degenerative diseases but it also plays an important role for the preparation of peptide fibres and peptide-based biomaterials. it is therefore extremely important to understand the mechanisms involved in peptide aggregation and be able to control them. studies were performed on a library of amphiphilic peptides, designed around the sequence of a model antimicrobial peptide rich in leucine and lysine. the library also included peptide hybrids in which natural amino acids were replaced by non-proteinogenic omega-amino acids, such as 6-aminohexanoic acid and 9-aminononanoic acid. the aim was to estimate the aggregation and its correlation with the biological activity by using a fluorescence technique commonly employed to calculate the cmc (critical micelle concentration) of surfactants. peptides and peptide hybrids were synthesized on solid support using the fmoc polyamide protocol. they were purified by semi-preparative rp-hplc and characterized by esi-ms and analytical rp-hplc. the aggregation behaviour of the synthesized molecules was investigated in water by steady-state fluorescence measurements using pyrene as fluorescent probe. peptides were dissolved in water/pyrene or water/pyrene/0. fluorescence spectroscopy has become an extremely valuable technique for conformational studies of biopolymers, the development of peptide-based chemosensors, and biochemical research in general. in this connection, synthetic amino acids as fluorescent probes to be incorporated into a peptide chain may exhibit significant advantages over the related protein (trp and tyr) residues in terms of potentially different and ameliorated properties. we recently designed and prepared a new fluorescent amino acid, antaib, based on a planar anthracene core and belonging to the class of achiral, ciα↔ciα cyclized, cα-tetrasubstituted α-amino acids (strong β-turn and helix inducers in peptides). peptides based on antaib combined with (l)-ala residues were synthesized and subjected to a conformational analysis. more specifically, the protected derivatives boc-antaib-oet (oh) and fmoc-antaib-otbu (oh) were prepared in seven steps from 1,2, 4 conformational transitions in peptides and proteins emerge to play the major role in the genesis and evolution of prion related diseases and alzheimer's disease (ad).1 in this context, conditions influencing this transition and the following aggregation process are of paramount interest. peptides and proteins that are involved in aggregation processes contain potential metal binding sites. the concentration of metal ions in the brain tissue is naturally high and zn in the mm range has been found in ad amyloid plaques. thus, it is widely accepted that metal complexation is one of the key incidents that lead to conformational transitions and aggregation. we present here a coiled coil based model peptide system with an intrinsic amyloid forming tendency which can be used to study the impact of different metal ions on secondary structure and aggregation. metal complexing histidine residues were incorporated to create potential binding sites which, depending on their position and the nature of the metal ion, dictate folding and aggregation. the time dependent conformational transition was monitored by cd-spectroscopy. aggregates were characterized by cryo tem. high resolution fticr-ms experiments revealed information on the stoichiometry of the peptide-metal complexes. in the absence of metal ions the presented peptides formed amyloids in a time range of weeks. depending on the his positions and milieu conditions, the nature of the metal ion determines folding and aggregate morphology. furthermore, metal binding was shown to inhibit the amyloid formation. a challenge to our understanding of protein folding is the design of a protein from first principle, i.e. starting from geometric restraints and applying properties of amino acids expected to be essential for folding to a defined structure. we developed a program to calculate the backbone coordinates of antiparallel strands to match the surface of an elliptical cylinder. various parameters like the number and shearing of the strands and the ellipticity of the structure can be varied. the relative orientation of the β-strands and the geometrical features of the hydrogen-bonds were derived from statistical analyzes of natural β-sheet structures. iterative cycles of core-packing with amino acid rotamers, molecular dynamics simulation and energy minimization with the charmm forcefield are used to include backbone movements and to minimize the risk of trapping an energetically unfavorable structure. the quality of residue packing is assessed with the help of criteria which proved to be successful in our design of β-sandwiches. at the protein surface, a network of salt-bridges with an excess of positive charges has been designed to increase the stability and the solubility of the protein. the final sequence is synthesized by standard solid phase fmoc-chemistry. insights gained from the analysis of the synthesized structure with ftir and cd spectrometry should help us to refine the parameters for subsequent designs. with this strategy, we hope to contribute to a better understanding of protein folding. the immunoglobulin binding protein g (1igd) from streptococcus species consists of 61 amino acids residues, which form two antiparalell-packed beta-hairpins and an alpha-helix in the middle of the sequence packed to the beta-sheet. the second hairpin was found to be stable in isolation. this fragment is therefore likely to be the first folding initiation site of the protein which could provide an adequate nucleation center on which the rest of the polypeptide chain would find a favorable environment to fold. thus, among the two beta-hairpins, the 48-59 fragment of 1igd corresponding to the c-terminal beta-hairpin was synthesized. in our studies, we investigated different environmental and temperature conditions for formation of the 48-59 beta-hairpin structure. its structure was examined by means of cd spectroscopy in water, buffer solutions (ph = 3 to 9) and in aqueous solutions of trifluoroethanol. additionally, its structure was investigated in the solid state by ftir spectroscopy. the cd studies revealed that the 48-59 fragment of 1igd in water forms mainly a statistical-coil structure, whereas the ftir technique shows formation of a regular beta-sheet structure. nmr spectroscopy and calorimetric measurements were carried out at various temperatures. our studies show that the 48-59 fragment at low temperature exists in an equilibrium between two conformations -a regular beta-hairpin and a statistical-coil. although increasing temperature resulted in shifting the equilibrium in the direction of the statistical-coil structure, the overall beta-hairpin shape of the 48-59 fragment was maintained. prion diseases are characterized by the conversion of the physiological cellular form of the prion protein (prpc) into an insoluble, protease-resistant abnormal scrapie form (prpsc) with an highly beta-sheet content [1] . the analyses of intrinsic structural propensities of the prp c-terminal domain showed an high conformational flexibility for the αhelix 2 fragment which indicates that this region may be particularly important in the prpc→prpsc transition [2] . therefore conformation-based approaches focalized on helix 2 region appear to be the most promising for the study of prion protein misfolding. recent studies on tetracycline properties showed that this molecule binds and disrupts prp peptide aggregates and inactivates the pathogenic forms of prp [3, 4] . a fluorometric titration of the fluoresceinated peptide corresponding to prion protein helix-2 with tetracycline has been carried out to determine the value of the apparent dissociation constant of this interaction (estimated to be 189 ± 7 nm). remarkably, the fluoresceinated peptide exhibits in water a canonical α-helical cd spectrum, that is maintained even in presence of tetracycline. accordingly, docking calculations and molecular dynamics simulations suggest that tetracycline interacts preferentially with the c-terminal end (residues 183-195) of helix-2 with a significant involvement of the treonine rich region. in the last decades, a series of discoveries have shed light on the role played by the carbohydrate moiety in glycoproteins. it has been shown that covalently linked sugar moieties influence peptide/protein properties such as hydrophobicity, conformation, biostability and bioactivity. the design of carbohydrate-peptide analogs with increased, retained or modified biological activity requires an understanding of their conformational preferences both in solution and in the receptor-bound state. in our recent work we have created two classes of well-structured linear and cyclic carbohydrate-modified analogs of opioid peptides, leu-enkephalin and leuenkephalin amide. the first class represents a group of compounds in which the linear peptide is alkylated at the n-terminal position by 1-deoxy-d-fructose unit, while its cyclic analog possesses an ester bond between the c-6 hydroxy group of the sugar moiety and the c-terminal carboxy group of peptide, 1-deoxy-dfructofuranose acting as a bridge between the leu-enkephalin terminal parts. the rigid 5-membered imidazolidinone ring is characteristic for the second class of compounds. in these adducts an imidazolidinone moiety connects the acyclic sugar residue with the linear peptide chain. in the corresponding bicyclic imidazolidinone analogs 19-membered ring is formed through an ester bond between the primary hydroxyl group of the d-gluco-pentitolyl residue and the cterminus of peptide. this work reports the comparative cd and ftir spectroscopic properties of the prepared glycopeptides in comparison with data on the non-modified flexible parent peptides performed in different solvents in order to expose the structural and conformational differences caused by a keto-sugar, rigid 5membered imidazolidinone ring and/or cyclization. the α-helical coiled coil structural motif consists of two to five α-helices which are wrapped around each other with a slight superhelical twist. the simplicity and regularity of this motif have made it an attractive system to study the role of complementary interactions for protein folding. here we present a systematic study showing that intermolecular electrostatic interactions between positions e and g of the helices are in competition with the intramolecular interactions between positions e/b and g/c. those competitive interactions affect folding and stability of the motif which were monitored by temperature dependent cd-spectroscopy. incorporation of oppositely charged amino acids in positions e/b and g/c reduced considerably electrostatic repulsion between equally charged amino acids in positions e and g. in addition coiled coil stability can be increased by the alkyl part of the amino acid side chains in positions e and g. studies with natural and unnatural amino acids showed that the longer this alkyl part the better is the hydrophobic core protected from solvent. therefore the repulsion of equally charged amino acids in positions e and g can be overruled by involving them either into attractive intrahelical electrostatic interactions or into hydrophobic core formation. human cystatin c (hcc) is a 120 amino acid residues protein that reversibly inhibits papain-like cysteine proteases. this inhibitor belongs to the amyloidogenic proteins shown to oligomerize through 3d domain swapping mechanism. the crystal structure of hcc reveals the way the protein refolds to produce symmetric dimer while retaining the secondary structure of the monomer. the monomeric form of hcc consists of a core with a five-stranded antiparallel β-sheet wrapped around a central α-helix. the hcc dimerization is preceded by an opening movement of l1 loop from β2-l1-β3 hairpin and separation of the β1-helix-β2 fragment from the remaining part of the molecule. the amino acid sequence of β1-helix region suggests additional possible partial unfolding in the n-terminal part of helix. in order to investigate the structural stability of β1-helix region the peptide corresponding to the helix and its n-terminal truncated analogs was synthesized along with the peptide analogs of helix containing point mutations that could stabilize helical structure of the n-terminus. the peptides were synthesized by the solid-phase method using fmoc/tbu tactics. purified products were identified by maldi-tof. the secondary structure content was calculated from the cd spectra using selcon3. the random coil was the predominant structure of the peptide corresponding to the α-helical fragment of hcc and its n-truncated analogs. however, an increase of αhelix content was observed in some of the peptides corresponding to the helix containing point mutations. we expect that these mutations could stabilize the hcc monomer and suppress dimerization. the tumor suppressor protein p53 is a trarnscription factor that triggers cell-cycle arrest and apoptosis in response to genotoxic stress signals. the tetramereric structure of the p53, which is essential for its activity as a transcription factor, is formed as a dimer of dimers. while the primary dimer is constructed from inter molecular formation of a two-stranded anti-parallel b-sheet and a two anti-parallel a-helix bundle, the secondary dimer is stabilized through interactions between residues on the surface of the primary dimer. from various substitution experiments on p53, it has been shown that hydrophobicity of phe341 is critical for the tetramer formation of p53. also we have substituted three phenyl groups of p53 with cyclohexylalanine (cha) and showed that phe341cha is dramatically stabilized against temperature, chemical denaturant, and organic solvent by cd measurements. here, to clarify the mechanism of the stabilization of phe341cha, we analyzed its three dimensional structure using x-ray crystallography. we obtained two kinds of crystals, one is a hexagonal bipyramid crystal in the space group of p6422 with a=50.12 å, b=50.12 å, c=48.18 å diffracted to about 2.0 å, and another is tabular crystal in the space group c2 with a=77.25 å, b=50.04å, c=55.10 å diffracted to about 2.1 å. in these crystals, the peptides formed tetramers which are very similar to those observed in the wild-type. the structure of the pocket where the side chain of cha341 is incorporated was defined to elucidate the hydrophobic interaction to determine the stability. helices shown in proteins, as a secondary structure, almost always form right-handed screw sense. this right-handedness is believed to result from the chiral center at the αposition of proteinogenic l-α-amino acids. among proteinogenic amino acids, l-isoleucine and l-threonine possess an additional chiral center at the side-chain β-carbon besides the α-carbon. however, no attention has be paid how the side-chain chiral centers affect the secondary structures of their peptides. recently, we have reported that sidechain chiral centers of chiral cyclic α,α-disubstituted amino acid (s,s)-ac(5)c(dom) affected the helical secondary structure of its peptides, and the helical-screw direction could be controlled without a chiral center at the α-carbon atom. herein, we synthesized a chiral bicyclic α,α-disubstituted amino acid (r,r)-ab(5,6)c and its homopeptides, and studied the relationship between the chiral centers and the helical-screw handedness of peptides. contrary to the left-handed helices of (s,s)-ac (5) four threefinger-toxins (tfs) have been purified from the pooled venom of golden krait (bungarus fasciatus, i.e. bf) from thailand and studied previously. these peptide toxins contain 60-65 residues and 4 or 5 pairs of disulfide bonds, and are rich in β-structure. we herein analyzed the tf-isoforms in bf venoms from kolkata (eastern india), hunan province (eastern china) and indonesia to study the geographic variations and structure-function relationships of the venom polypeptide family. a total of five or six tfs of low lethality were purified from each of the geographic venom samples, the n-terminal sequences and accurate masses of the peptides were determined. the cdnas encoding some of these tfs were also cloned and sequenced. full peptide sequences were deduced and match with those of the tfs purified from crude venom. intra-species variations of the venom tfs were found to be surprisingly high since sequence-identities between the majorities of orthologous toxins in different geographic samples are only 75-80 %. most of the bf proteins were not neurotoxic by electrophysiological assays using chick biventer-cervicis and mouse diaphragm neuromuscular tissues. the toxins appear to be associated with weak toxins or non-conventional snake venom tfs as analyzed by a phylogenetic tree. the reason behind their lack of neurotoxicity would be discussed. v. moussis, e. panou-pomonis, c. sakarellos, v. tsikaris peptides involved in neurodegenerative diseases can adopt at least two different stable secondary structures. amyloid-forming proteins can experience a conformational transition from the native, mostly α-helical structure, into a ß-sheet rich isoform. the latter conformation is probably present in intermediates for the formation of amyloids. the conformational change can be triggered by protein concentration or environmental changes. therefore, our aim was to generate a de novo designed peptide that contains structural elements for both, stable α-helical as well as ß-sheet formation. this model peptide can be used to elucidate the conformational changes dependent on concentration and ph.1 the design is based on the well studied α-helical coiled coil folding motif. the conformation and structure of the resulting aggregates were characterized by cd-spectroscopy and cryo transmission electron microscopy. as a result, three distinct secondary structures can be induced at will by adjustment of ph or peptide concentration. low concentrations at ph 4.0 yield globular particles of the unfolded peptide whereas, at the same ph but higher concentration, defined ß-sheet ribbons are formed. in contrast, at high concentrations and ph 7.4, the peptide prefers highly ordered α-helical fibers. in conclusion, we successfully generated a model peptide that, without changes in its primary structure, predictably reacts on environmental changes by adopting different defined secondary structures. thus, this system allows to systematically study now the consequences of the interplay between peptide primary structure and environmental factors for conformation on a molecular level. cells respond simultaneously to a multitude of different signals. inside a cell signals from activated receptors are integrated by networks of enzymatic reactions and molecular interactions, leading to a spectrum of cellular responses. in order to understand the relationship between a specific cellular stimulus and a cellular response, methods are required to detect in parallel the pattern of molecular interactions. a large number of molecular interactions is mediated by protein domains, binding to linear peptide motifs. lysates of activated and resting cells were incubated on peptide microarrays carrying peptides corresponding to such binding motifs of signalling domains. binding of proteins to a spot of the array was probed by immunofluorescence. jurkat t cells were stimulated either with the phosphatase inhibitor pervanadate or with antibodies directed against cell surface receptors. upon activation of t cells, numerous changes in the pattern of molecular interactions were detected for a total of 10 proteins and 30 peptides. these changes were caused either (i) by masking or unmasking of a binding domain which resulted in a reduced or increased binding of a protein to the microarray or (ii) by recruitment of a protein into a complex that in turn bound to the microarray. the changes were dependent on the nature of the stimulus. the human melanocortin receptor 1 (hmc1r) was constructed to contain a flag epitope and a hexahistidine tag at the amino-terminus as well as at the carboxyl terminus to facilitate purification. stably transfected hmc1r in human embryonic kidney (hek293) cell lines that expressed the receptor resulted in a kd value of 0.1 and 0.2 nm respectively in each case when the super potent agonist mtii was competed with [125i]ndp-α-msh. treatment of the tagged receptors in the hek293 cells with agonist resulted in down-regulation which indicates that these tagged receptors retain their biological functions. the hmc1r was solubilized from cell membranes with n-dodecyl-β-d-maltoside and purified at a nickel chelating resin and a newly constructed affinity column. the purified hmc1r was a glycoprotein that migrated on sds/page with a molecular mass of 58 kda. the results from matrix-assisted laser desorption ionization-time of flight (maldi-tof) mass spectrometry was used to identify and characterize peptides derived from the hmc1r following in-gel digestion with chymotrypsin. the phosphorylation sites were identified on the purified human melanocortin receptor 1 with agonists (peptide vs small molecule) treatment. the discovery of antibiotics in the 1930s has been one of the most revolutionary events in the history of medicine. however, during last decades, the increase of antibiotic resistance has significantly hampered the application of antibiotics. therefore, further scientific effort to find new antibiotics with novel mechanisms of action is of high importance. insects are the largest and the most diverse group of living animals on earth. they have potentially been confronting high variety of microorganisms. as a result, they have evolved powerful defense system, thus representing vast source of novel potential therapeutics. we chose larvae of fleshfly neobellieria bullata for identification and characterization of new promising molecules, peptides or proteins, which participate in immunity response against microbial infections. the hemolymph of the third-instar larvae of neobellieria bullata was used for isolation. the larvae were injected with bacterial suspension of escherichia coli or staphylococcus aureus to induce antimicrobial response. the hemolymph was separated into crude fractions, which were subdivided by rp-hplc. isolated fractions were characterized by uv-vis spectroscopy, amino-acid analysis, mass spectroscopy, 1-d and 2-d sds electrophoresis, capillary zone electrophoresis, ion-exchange hplc, tryptic digests and n-terminal sequencing. we found out significant antimicrobial activities against escherichia coli, staphylococus aureus or pseudomonas aeruginosa in several fractions. using real-time pcr, we followed and compared levels of mrna of different proteins and peptides in induced and non-induced larvae. despite the fact that many technological advances are currently involved in proteome analysis, like two-dimensional gel electrophoresis and mass spectrometry, there is still a great need for the development of novel engineered chemical probes for proteomics and interactomics. here, we describe our approach concerning the study of proteome and interactome of proteins involved in cell-matrix interactions. it relies on the use of a small synthetic inhibitor chemically modified to allow for its immobilisation to magnetic beads or affinity chromatography materials. proteins will be detected together with their native interaction partners because of nondenaturing conditions. this general procedure is applied for the enrichment of metalloproteinases, especially matrix metalloproteinases, which are potential target in tumour therapy. hydroxamic acids are known to be potent inhibitors of metalloproteinases. marimastat is a reversible inhibitor with a good potency and shows activity towards a wide range of metalloproteinases. the synthesis of new marimastat derivatives will be reported. the parent compound is modified with a linker to allow immobilisation on a solid surface. binding studies were performed using surface plasmon resonance. this approach is not only appropriate for the generation of metalloproteinase proteome subsets by affinity column or using magnetic beads, but also to enrich and isolate interaction partners of the target proteins. the present report summarizes the latest data devoted to theoretical and experimental investigation of the high temperature solid state catalytic isotope exchange reaction (hscie) that takes place in peptides and proteins by the action of deuterium and tritium [1] . the available ms-procedures, designed to estimate the amount of protein, are aimed at derivatization at different stages of sample preparation, and as the best result, it is only possible to achieve quality comparison of the objects involved. the hscie reaction allows the production of evenly deuterium labelled proteins and peptides, and their application makes it possible to create a qualitative mass spectrometry method for protein analysis. introduction of definite amounts of these deuterium-labeled proteins into biological objects, prior to isolation, separation and trypsinolysis, will generate quantitative information concerning the composition of the proteins under study. tritium labelled proteins produced at a temperature of 100-120oc carry the isotopic label in all the peptide fragments and completely retain their enzymatic activity. the proteins' reactivity is dependent on their three-dimensional structure. the hscie reaction has been shown to be used both in the production of tritium labelled proteins and in the investigation of spatial interactions in protein complexes. in addition, evenly deuterium and tritium labelled peptides can be used in studies of the kinetics and transformation paths of peptides in the organism's tissues. immunization of mice with type ii collagen (cii) from rat leads to development of collagen-induced arthritis (cia). susceptibility to cia is associated with the major histacompatibility class ii protein h-2aq that binds the glycopeptide epitope cii260-267 (1) and presents it to helper t cells. [1] to explore the interactions in the system and to stabilize 1 towards in vivo degradation, amide bond isosteres have been introduced in its backbone.glycopeptide 1 was virtually docked into the binding site of a comparative model of h-2aq. based on the hydrogen bonding network between the peptide backbone and h-2aq, the amide bond between ala261-gly262 was chosen for isosteric replacement. to vary the geometric and hydrogen bonding properties, mimetics of the dipeptide were synthesized with the amide bond replaced by ψ[ch2nh], ψ[coch2] and ψ[(e)-ch=ch], respectively. these were introduced in 1 using solid-phase synthesis to give glycopeptidomimetics that were biologically tested for their ability to bind to the h-2aq protein and for recognition by t cells. shown to be a potent neuroprotective factor in various pathophysiological models. despite its therapeutic potential in diverse neurodegenerative diseases, its short in vivo half-life limits its utility as a useful clinical agent. moreover, the development of a peptidomimetic that reproduces the pharmacological activity of pacap is unlikely since the pharmacophores are spreaded throughout the entire peptide chain. therefore, the development of pacap analogues with lower susceptibility to proteolysis represents a first step toward clinical applications. in the present study, derivatives of both pacap27 and pacap38 with particular chemical modifications were developed targeting specific peptidase sites of action. results indicate that the incorporation of an acetyl or a hexanoyl group at the n-terminus and modifications at the ser2 residue contributed to increase stability against dipeptidyl peptidase iv, the major enzyme involved in pacap degradation. moreover, after determination of pacap metabolites in human plasma, the amide bond between residues 21 and 22 was substituted by a ch2nh surrogate and this derivative showed increased plasma stability. all modified peptides were tested for their ability to induce pc12 differentiation. the effects of pacap analogs on pc12 cells are mediated through the pac1 receptor which is the major receptor involved in the neuroprotective effects of pacap. this study exposes interesting data concerning pacap metabolism in isolated human plasma and demonstrates the possibility of increasing the metabolic stability of pacap without significantly reducing its biological activity. species of the fungal genus trichoderma are commercially used as bioprotective agents against fungal plant diseases. more than 400 strains were collected from their natural habitats and evaluated for biocontrol properties. seven of the most active isolates exhibiting strong biological activity towards eutypa dieback and esca diesease of grapevine were classified as trichoderma brevicompactum, or shown to be closely related to that species. these strains were screened for production of peptaibiotics. the formation and synergistic action of hydrolytic enzymes and peptaibiotics were to play an important role in mycoparasitism. after background and aims: conotoxins are short, disulfide-rich neurotoxins that target various ion channels and receptors. these peptides have desirable pharmacological properties to become therapeutics for neurological disorders; several conotoxins have already reached clinical development stage. our long-term goal is to improve bioavailability, metabolic stability and pharmacokinetics of conotoxins using a variety of chemical modifications. methods: we designed and chemically synthesized conotoxin analogs containing two distinct types of backbone modifications: (1) peptide-peptoid chimeras (conopeptoids) of alpha-conotoxin imi and (2) peptide chimeras of mu-conotoxin kiiia containing non-peptidic "backbone spacers". results: conopeptoid-imi, containing ala9 replaced by n-methyl glycine potently blocked activity of nicotinic acetylcholine receptors. in mu-conotoxin kiiia, aminohexanoic acid or amino-3-oxapemtanoic acid were inserted to be a part of the peptide backbone. the two oxidized analogs containing "backbone prosthesis" differed in their hydrophibicity profile, but they both potently inhibited neuronal sodium channels. conclusion: our results suggest that backbone engineering may become an effective method of producing conotoxin analogs with modified bioavailability. to increase the stability and the therapeutic efficacy of peptide sequences from myelin oligodendrocyte protein (mog) that act as multiple sclerosis (ms) antigens, we grafted them onto a framework of a particularly stable class of peptides, the cyclotides. they are a recently discovered family of cyclic plant peptides with superb intrinsic stability. the limitations of linear peptides as drugs due to their instability and poor bio-availability can be overcome by using the cyclotide scaffold as a framework for novel drug design. peptide epitopes from mog protein were incorporated onto the framework of the model cyclotide kalata b1 by means of boc-spps approach. after successful backbone cyclisation and oxidation of the cysteine residues, the peptides were purified to high purity with rp-hplc. nmr chemical shift analysis was used to assess whether the grafted analogues have a stable scaffold, similar to that of kalata b1. a structure of a representative peptide was determined and it shows remarkable resemblance to the native scaffold of kalata b1. the activity of the bioengineered peptides has been tested in vivo. a group of mice injected with one of the peptides have shown a depression in the clinical score and have not fallen ill. this is an exciting result that shows the first active bioengineered cyclotide in an animal model of disease. the structural information from nmr studies will be used in conjunction with the results from the activity studies in a feedback loop to design second-generation lead molecules. a.d. de araujo, p.f. alewood conotoxins are small, disulfide-rich peptide neurotoxins produced in the venom of marine cone snails that enable these molluscs to capture their prey. these compounds exhibit a high degree of selectivity and potency for different ion channels and their respective subtypes, making them useful tools in the investigation of the nervous system. due to the key role of ion channels in many physiological processes, conotoxins are also excellent drug lead candidates in drug discovery, with some examples currently undergoing clinical trials and one recently approved drug (prialt®). like other peptide drugs, the use of conotoxins in drug development is limited by the low oral bioavailability of these compounds due to pre-systemic enzymatic degradation and poor penetration through the intestinal mucosa. peptide analogs that mimic the native structure and incorporate rationally designed non-natural modifications in the disulfide framework or peptide backbone may exhibit increased resistance to proteolytic degradation. in biological environments, disulfide linkages are susceptible to attack by enzymes and reducing agents (such as glutathione). therefore we carried out the synthesis of redox-stable conotoxin analogs in which intrinsic disulfide bonds were replaced by thioether linkages. in this work, wehave explored two solid-phase synthetic routes in the preparation of thioether conotoxin mimetics: the first route based on peptide assembly using a tetra-orthogonally protected lanthionine building block, and the second route based on intramolecular on-bead cyclisation between cysteine and betabromoalanine residues. thyrotropin releasing hormone (trh, l-pglu-l-his-l-pro-nh2), a tripeptide synthesized in the hypothalamus, operates in the anterior pituitary to control levels of tsh (thyroid-stimulating hormone) and prolactin. the thyrotropin-releasing hormone (trh) receptor (trh-r) belongs to the rhodopsin/β-adrenergic receptor subfamily of seven transmembrane (tm)-spanning, g protein-coupled receptors (gpcrs). the two g-protein-coupled receptors for trh, trh receptor type 1 (trh-r1) and trh receptor type 2 (trh-r2), have been cloned from mammals and are distributed differently in the brain and peripheral tissues. the trh receptor subtype-1 appears to mediate the hormonal and visceral effects, whereas trh receptor subtype-2 has been implicated in its central stimulatory actions. identification of critical features of the trh, separation of its multiple activities through design of selective analogues and affinity labels have been elusive and unfulfilled goals for more then 30 years. this presentation will highlight our studies on effect of the biological activity of trh with the introduction of alkyl groups of varying sizes at the n-1 and c-2 position of the centrally placed histidine residue of trh peptide. the requisite n--boc-dialkyl-l-histidines as building scaffolds have been synthesized in six steps from l-histidine methyl ester dihydrochloride and used for the synthesis of various trh analogues. ghrelin, the natural ligand for the growth hormone secretagogue receptor (ghsr-1a), has received a great deal of attention due to its ability to stimulate growth hormone secretion and to control food intake. during these last years, ghrelin analogues or mimetics gained interest for their implication in food intake regulation. in the course of our studies concerning ghrelin analogs, we developed new ligands of the ghsr-1a based on heterocyclic structures. interestingly, one heterocyclic family presented high affinity for the ghrelin receptor. a structure activity study was performed within this family and led to potent ghsr-1a agonists and antagonists. the binding affinities were determined by displacement of radiolabelled ghrelin and the agonist or antagonist character was measured by intracellular calcium mobilisation. the first in vivo results revealed that in vitro activities and in vivo responses were not correlated. particularly, binding to ghsr-1a and in vivo gh release and food intake control were not fully correlated. these results strongly suggest the presence of receptor subtypes that modulate ghrelin actions. some examples will be reported. further investigations are going on in the laboratory. background and aims: alzheimer's disease (ad) related beta-amyloid (aβ) peptides possess high propensity towards aggregation. nowadays one of the major directions of the drug-design against ad is the synthesis of putative amyloid aggregation inhibitor molecules (aai) which are able to hinder the formation of these toxic amyloid aggregates. in the present work we report the design, synthesis and investigation of putative aais derived form the peptide sequence aiigl identical to aβ(30-34). methods: aβ(1-42) peptide and putative aggregation inhibitors were synthesized manually using fmoc-chemistry and dcc/hobt activation. studies on both the aβ aggregation and the effect of the aais were performed with several instrumental techniques. the total amount of the aggregates was determined by thioflavine-t binding assay, while their size distribution was characterized with dynamic light scattering (dls). aggregated aβ forms were visualized with transmission electron microscopy (tem). the binding affinity of the aais to aβ fibrils was studied in saturation transfer nmr experiments, while in vitro viability assays were performed on cultured human sh-sy5y neuroblastoma cells to monitor the neuroprotective effect of the amyloid aggregation inhibitors. results and conclusions: 32 derivatives of aβ(30-34) were synthesized and tested concerning their neuroprotective effect against aβ-mediated toxicity. the most promising candidates were examined with physico-chemical methods to characterize their aggregation altering ability. the pentapeptide riigl-amide proved to be the most powerful neuroprotective compound, and it was also able to alter considerably the aggregation kinetics of aβ(1-42) . this molecule might serve as a lead compound in the drug-design against ad in the future. m. mattiuzzo, a. bandiera, m. benincasa, i. samborska, m. scocchi, r. gennaro antimicrobial peptides (amps) are ancient molecules of the innate immune defence system. most of them kill bacteria by lysing their membranes. the proline-rich group of amps represents an exception, as they act via a permeabilization-independent mechanism that is likely based on recognition of molecular targets/transporters. however, specific internal targets have not yet been identified for most of these amps. bac7 is a pro-rich amp isolated from bovine neutrophils that is capable to translocate across membranes to target hypothetical intracellular proteins. in this study, we used a molecular approach to identify putative targets for bac7 by selection of peptide-resistant mutants followed by identification of the genes responsible of this resistance. to this aim, an e. coli strain susceptible to the fully active fragment bac7(1-35) was subjected to chemical mutagenesis and a number of peptide-resistant mutants was obtained. a pool of genomic dna from these mutants was used to construct a plasmid library that was used to transform a susceptible strain. this approach allowed the identification of 14 different clones that provided a high level of resistance to bac7. sequence analysis revealed the presence of genes originating from five different regions of the e. coli chromosome. among them, one clone contained ptrb, a gene coding for a serine peptidase broadly distributed among gram -bacteria, which could be involved in resistance by degrading the peptide. other resistanceconferring clones, which encode for membrane proteins that may be involved in peptide translocation across the memmbrane, are currently under investigation. lycotoxins are peptides from the venom of the wolf spider that were predicted to have an amphipatic alpha-helical structure and confirmed to possess significant antimicrobial and pore-forming activities. [1] we became interested in these peptides as potential leishmanicidal agents against leishmania donovani promastigotes and leishmania pifanoi amastigotes. thus, lycotoxin i (lyi) and lycotoxin ii (lyii), [1] and shortened analogues lyi1-19, lyi1-15, lyii1-21 and lyii1-17, were synthesized as c-terminal carboxamides. short-and long-term parasite proliferation measurements showed all peptides except lyi1-5 to be active against both promastigotes and amastigotes at the micromolar range, and suggest peptide effects on parasites to be irreversible. lyii, that showed the lower activity, became more leishmanicidal upon residue trimming, whereas the most active lyi displayed the opposite behaviour. a set of complementary techniques showed that lycotoxin peptides are membrane-disruptive to promastigotes. electron microscopy showed that two populations of promastigotes, one with intact parasites and the other extensively damaged, are formed upon addition of the peptides at their ec50. all peptides were non-hemolytic for sheep erythrocytes below 20 micromolar. tissue transglutaminase (tg2) is an enzyme that plays a key role in the pathogenesis of the celiac disease. tg2 is the main autoantigen recognized by the antiendomysium antibodies and, furthermore, catalyzes the deamidation of strategic glutamine to glutamic acid within the sequence of immunodominant gliadin epitopes. recently, another unexpected role for surface tg2, in the innate immune response in the celiac disease, has been suggested. it follows that tg2 inhibitors might represent a potential attractive pharmacological alternative to the gluten-free diet that, nowadays, is the only possible therapy for celiac patients. starting from the sequence of the heptapeptide pqpqlpy, known to be a high affinity substrate of human tg2, we have synthesized new analogs replacing pro3 with different constrained amino acids (d-pro, pip, chg, ind, deg, inp, hyp, thz)) with the aim to develop specific inhibitors of tg2. actually, proline residues present in the gluten epitopes are important in determining the immunogenicity of the epitopes and the specificity of tg2. herein, we describe the preliminary conformational studies of the synthesized analogs by cd and nmr spectroscopy and molecular modeling methods. the structural features of the peptides have analyzed in different environment. given the role of the domain pqpqlpy in the gliadin proteins, structural analysis on its analogs are of considerable interest. the results of our studies might be useful to clarify the role of the proline residues in the interaction of the gluten epitopes with tg2 and, consequently, to gain new insight in the molecular mechanism of celiac disease. carnosine and related histidine-containing dipeptides are known to react with high efficiency with the products of lipid peroxidation, namely 4-hydroxy-trans-2,3nonenal (hne) and other alpha, beta-unsaturated aldehydes, preventing their reaction with nucleophilic residues in proteins and nucleic acids. histidyl hydrazide alone or conjugated with aminoacids, long chain fatty acids, cholesterol and alpha-tocopherol synthesized in our laboratories demonstrated higher aldehydesequestering efficiency than carnosine, and were also efficient in protecting sh-sy5y neuroblastoma cells and rat hippocampal neurons from hne-mediated death. the cytoprotective efficacy of these compounds suggests their potential as therapeutic agents for disorders that involve excessive membrane lipid peroxidation. lantibiotics are antibiotic natural products that are synthesised ribosomally and undergo extensive post-translational modification, resulting in multiple thioether bridges and dehydro amino acids in the mature peptide. one such lantibiotic is mersacidin, which is produced by bacillus sp. and exhibits extremely promising in vitro and in vivo efficacy versus a number of clinically relevant pathogens, most notably methicillin-resistant staphylococcus aureus (mrsa). mersacidin is believed to function by binding to the bacterial cell wall precursor lipid ii, thereby preventing its incorporation into the growing peptidoglycan network. in an attempt to better understand this mode of action and develop more active analogues, we have embarked upon its chemical derivatisation. some of these modifications resulted in an altered antibacterial spectrum, permitting some insight into tentative structure-activity relationships. the characterisation of these structurally complex compounds via a combination of multidimensional nmr and tandem mass spectrometry will also be presented. conjugation of peptides with different moieties, such as peg, lipids, carrier proteins and toll-like receptor ligands is an established approach to improve their pharmacokinetic profile for drug use and/or to enhance their immunogenicity as subunit vaccines. the development of suitable conjugation strategies for peptides of any complexity is therefore fundamental for their effective use in human therapeutic applications. here we describe our strategy to engineer a trimeric coiled coil to obtain a covalently linked, structurally stable construct endowed of extra functionality for further derivatization. we previously showed that covalent stabilization of the designed trimeric coiled coil izn17, by interchain disulfide bonds, yielded an extremely potent and broad inhibitor of viral infection, (ccizn17)3, [1] . this potent inhibitory activity makes (ccizn17)3 not only attractive as an antiviral compound, but also as an immunogen to elicit a neutralizing antibody response [2] . we have now developed an alternative synthetic strategy to obtain the covalently-linked izn17 trimer, which allows the presence in the molecule of a free thiol for subsequent chemoselective reactions. first, we showed that stable interchain thioether bonds can be effectively substituted for the disulfides. second, we devised an orthogonal cysteine protection scheme which allows formation of the thioether bonds, while leaving an extra free cysteine on demand. this thiol group can be used for conjugation of the trimeric coiled coil to adjuvant/carrier proteins or, as reported more specifically here, to a peg40kda moiety. human igg is a most abundant type of immunoglobulin in serum and most of antibody drugs applied for therapy of cancer and autoimmune diseases also belong to this group of human immunoglobulin. specifically binding peptide to human igg is very useful for detection and purification as an affinity ligand of human igg. although some previous reports described such peptides, we tried here to isolate high-specific and high affinity ligands by employing random peptide-displayed t7 phage library. our t7 random peptide phage library possesses a total diversity of 10 powered 10th consisting of different sequence length constrained by disulfide bond. by biopanning against human igg, we isolated several igg specific clones from our library. the peptides displayed on these phages shared some common sequences in the limited region surrounded by cys residues, which suggests they are essential for binding. these clones bound only to fc region of igg and did neither other types of human immunoglobulin nor igg of other animals. a synthetic peptide derived from a phage clone showed a sub-nanomolar of kd value in binding to human igg fc on spr analysis. these results indicate that the peptide motifs obtained here are a strong candidate of human igg-specific affinity ligand for detection and purification of igg. therefore, we are now going on constructing detection and purification system using modified and improved peptide motifs. synthesis of glp-1 analogues as potential agents for blood glucose control p. kanda, r.p. sharma, c.p. hodgkinson in this study, we synthesised a panel of glp-1 analogues stabilised against dpp-iv degradation through either selective amino acid substitutions for ala8, or introduction of amide bond surrogates into the peptide backbone between ala8 and glu9. each was made by standard fmoc or boc chemistry, purified by hplc, and characterized by electrospray mass spectroscopy. all derivatives except one bearing a hydrazine modification were stable to dpp-iv proteolysis for up to 48 hours at ph 7.5, 37o. each was tested for its ability to augment insulin release from a glucose-sensitive, murine insulinoma-derived tc-6 cell line in culture. it was found that each compound acted as a glp-1 agonist to varying degrees, with some exhibiting higher activity than native glp-1 toward promoting insulin release. the most active analogues have been chosen as candidates for stabilisation against renal clearance in efforts to develop new glp-1 analogues with therapeutic potential. the high propensity of the glucose regulatory hormone human islet amyloid polypeptide (iapp) to misfold and aggregate into cytotoxic beta-sheets and fibrils is strongly associated with beta-cell degeneration in type ii diabetes (t2d) and precludes its pharmacological use for the treatment of diabetes. iapp analogs that combine solubility, lack of cytotoxicity, and bioactivity with the ability to block iapp aggregation and cytotoxicity could thus be of high biomedical interest. here we apply a minimalistic conformational restriction strategy to redesign the extremely insoluble and amyloidogenic 37-residue iapp sequence into a soluble, nonamyloidogenic, noncytotoxic, and bioactive iapp mimic (yan et al., pnas (2006) ). the designed mimic has nearly the same sequence as iapp but is highly soluble, nonamyloidogenic, noncytotoxic and a full iapp receptor agonist. in addition, the mimic binds with high affinity iapp and blocks and reverses with nanomolar activity its cytotoxic self-assembly which makes it to the most potent known iapp cytotoxic self-assembly inhibitor. due to its bifunctional nature, the mimic might find therapeutic application for the treatment of diabetes both as an inhibitor of amyloid cytotoxicity and as a soluble iapp receptor agonist. our findings offer a proof-of-principle of a chemical design approach for generating a novel class of highly potent inhibitors of polypeptide cytotoxic selfassembly which are nonamyloidogenic mimics of the native amyloidogenic sequence as well. such reengineered biomolecules -the design of novel mimics is in progress-are of high biomedical significance for understanding the mechanism of protein aggregation diseases and for the development of prospective therapeutic treatments. peptides that are capable of targeting abnormal changes of living tissue can be very useful in early detection or diagnosis of, e.g., cancer. conjugating a functional agent, an effector unit, to such a peptide may provide the agent with improved pharmacodynamic properties.the specificity of a thiol group for reactive groups offer a unique way to attach effector units to cysteine-free linear or cyclic peptides. tumor targeting peptides were synthesized by fmoc-type solid phase methods. peptides cyclic by cystine were modified by lactam bridges. fluorescein, metal (e.g. lanthanide) chelates and cytotoxins were coupled to tumor targeting peptides via e.g. a peg-type spacer, or the conjugates were immobilized on plates for adhesion assays. the method was uncomplicated and gave stable conjugates with good solubility. the approach is useful in making stable peptide-effector conjugates and sets of them for e.g. detection assays such as delfia method and has prospective use in development of diagnosis and therapy. antibacterial proline-rich peptides -synthesis and antibacterial activity d. knappe, r. hoffmann the antibacterial proline-rich peptide family, originally isolated from insects, shows remarkable activity against diverse bacterial and fungal pathogens. while more and more bacterial pathogens become resistant to common drugs, this part of insect innate immunity provides a new promising approach to develop future peptide-drugs. proline-rich peptides possess a significant sequence homology and share a common mechanism of action. in addition oglycosylated threonine residues of drosocin and formaecin appear to be necessary for full antimicrobial activity, although the significance of the carbohydrate moiety in interaction with intracellular targets is still unknown. we synthesized analogues of different antibacterial peptides on solid phase by the fmoc-tbustrategy. the combination or insertion of sequence regions from different native antibacterial peptide sequences offers several advantageous effects, including further reduction of toxicity and broadening of the antimicrobial activity. furthermore, mimicking the o-glycosylation site and changing the carbohydrate moieties, may yield new synthetic approaches to increase both the activity and the selectivity of these oligopeptides. new immunotherapeutic approaches have been developed for treatment of neurodegenerative diseases of the alzheimer's dementia (ad) type. the identification of a ß-amyloid-plaque specific epitope, aß(4-10) (frhdsgy) [1] , recognised by therapeutically active antibodies from transgenic ad mice, provides the basis for development of new ad vaccines and for molecular ad diagnostics. in order to produce immunogenic conjugates, the aß4-10 epitope was attached via thioether linkage to synthetic carriers of well-defined structures, such as tetratuftsin derivative (ac-[tkpk(clac)g]4-nh2) and its elongated version by a helper t-cell epitope (ac-fflltriltipqsld-[tkpk(clac)g]4-nh2); sequential oligopeptide carrier (ac-[lys(clac)-aib-gly]4-oh) and multiple antigenic peptide (clac-lys(clac)-lys(clac-lys(clac))-arg-arg-ßala-nh2). the epitope conjugates containing a cysteine residue either at the c-or n-terminus, and the chloroacetylated carriers were prepared by spps according to boc/bzl strategy. conjugation reactions were performed in solution under slightly alkaline conditions, and monitored by hplc and high resolution-ms. structures and molecular homogeneities of all epitope peptides, carriers and conjugates were ascertained by hplc, maldi and esi-fticr-ms. conformational preferences of the synthesized compounds in water and in tfe were examined by cd spectroscopy. comparative binding studies of the conjugates with a mouse anti-amyloid protein beta-(1-17) monoclonal antibody were performed by indirect elisa. experimental data showed that the chemical nature of the carrier, the epitope topology and the presence of a pentaglycine spacer between the epitope peptide and the carrier, had significant effects on the antibody recognition and on the secondary structures of the conjugates. the new cla analogue 1, containing ethylene bridge between phe nitrogen atoms, was found to exhibit unexpected stimulatory effect in the model of the in vitro humoral immune response in mice. to disclose the structure-activity relationship the nmr solution conformational analysis was carried out. the solid-state and solution conformational analysis of native cla indicated the existence of this cyclic system as a complex mixture of conformations [1] . the nmr spectra recorded at 600 mhz in chloroform at 214 k showed the different conformational behaviour of both cyclopeptides: cla exists as one isomer [1] , peptide 1 is in an equilibrium among at least of three conformers. the picornaviruses are small nonenveloped rna viruses with a single positive strand rna. the virus replication cycle starts after the penetration of the virus in the cytoplasm of the host cell. there are several stages of the virus life cycle used for attack. one of the most useful strategies for attacking of the virus includes inhibition of important for the virus lifecycle enzymes. the key enzymes in the replication of the picornaviruses are 3c and 2a proteases. changes in the active center of these enzymes make them incapable to produce polyprotein in vitro, therefore the inhibition by low molecular weight molecules could stop the viral replication in vivo. 3c protease plays a major roll in the enzymatic proteolysis of the initial viral polyprotein. the target compounds were based on structural modifications in the known as crucial for the 3cp inhibition activity dipeptides phe-gln by incorporation of additional amino acid and pyrrole moiety. the synthesis was cared out as multiple-peptide synthesis in parallel using stepwise spps, fmoc-strategy. the obtained compounds were tested for antiviral activity by agar-diffusion plaque inhibition test against coxsackievirus b1 replication in fl cell and on this base some structure-activity interpretations were made. histone deacetylases (hdac) play important roles in various aspects of regulation such as proliferation, differentiation, and aging by counteracting with histone acetyl transferases. the hdacs categorized in class-i and ii have a metalloprotease-related mechanism in its catalytic activity. these enzymes could be inhibited by small molecules bearing various zinc ligands such as hydroxamic acid and mercaptan. based on the structure of chlamydocin, which has a cyclic tetrapeptide framework, cyclo(-l-aoe-aib-l-phe-d-pro-), where aoe is (2s,9s)-2-amino-8-oxo-9,10-epoxydecanoyl, we have developed potent hdac inhibitors as shown in the figure. in the present study, we examined the effects of the chlamydocin hydroxamic acid (1) and ss-hybrid (2) on the diabetes model mice, kk-ay. the peptide (1) exhibited satisfactory activity to reduce both the blood glucose and blood insulin levels comparable to or even superior to those by pioglitazone, a pparγ agonist. the ss-hybrid (2) , which is expected to be reduced inside of cells to generate the corresponding thiol-containing cyclic tetrapeptide, also showed a significant effect but less than (1). the effect was dose-dependent from 3 mg/kg to 30 mg/kg. the effects of hdac inhibitors were also confirmed by the observation of in vivo histone hyperacetylation induced in the lymphocyte cells. synthetic peptides have a number of advantages over current vaccines. however, exploitation of synthetic peptides as vaccines has been limited by the small size; copy number, inefficient delivery, poor peptide immunogenicity and mhc restriction. we have developed chemical methodologies that overcome these limitations by synthesising and polymerising vinyl-peptides. protective b-cell and t-cell peptide epitopes from the oral pathogen porphyromonas gingivalis were identified for three different mhc restricted mouse strains using pepscan techniques. fmoc chemistry for spps was used to synthesize these peptides and a vinyl moiety was incorporated at the n-terminus using acryloyl chloride. after rp-hplc purification free radical polymerisation using ammonium persulphate and temed was used to polymerise the vinyl-peptides in the presence of either acrylamide or other vinyl-monomers to produce single peptide or multi-peptide polymers. size exclusion chromatography indicated that the peptide polymers were >2 million da. the peptide polymers were used to immunise each mouse strain (balb/c, cba and c57bl6) and the t-cell response induced was evaluated using proliferation and cytokine (elispot) assays. the peptide polymers were found to be highly immunogenic, the single peptide polymers were found to only induce a response in their respective mouse strain, however, the multi-peptide polymer containing all of the t-cell epitopes was found to induce a response in all three mouse strains. in conclusion, our data shows that the polymerisation method overcomes all of the limitations in developing a peptide vaccine and most importantly that of mhc restriction. cytotoxic substances are auspicious weapons in tumour therapy. this compounds inhibit cell division and proliferation, hence, they affect all cells that are able to divide. however, all these compounds act intracellularly, i.e. at first they have to enter the tumour cell efficiently. this is a serious obstacle when using highly effective cytostatica and the cause of severe adverse effects by using higher doses. our aim is to overcome this problem by using synthetic hybride molecules composed of the cytostatic agent, in our case derivatives of arglabin, covalently linked to shuttle peptides. in order to identify the most effective possibility we tested two different strategies. by using the peptide hormone npy, whose specific y receptors are often overexpressed by tumour tissues, we intended to address the chemotherapeutic selectively to y receptor expressing tumour cells via receptor mediated endocytosis. on the other hand, the cytostatic agent was covalently bound to a cell penetrating peptide derived from human calcitonin (hct). recently, a c-terminal fragment of human calcitonin was found to internalize into excised nasal epithelium while the receptor activating n-terminal part is lacking. for the class of hct derived carrier peptides previous studies suggested a receptor independent "lipid raft" mediated endocytotic mechanism of uptake. here we present comparative data investigating both strategies, the highly selective receptor mediated delivery and the highly efficient receptor independent delivery. we investigated the peptide uptake by various cell lines and examined the release of the cytostatic agents inside the cells and its toxic effects. background and aims: synthetic peptides provide a straight-forward access to rationally designed inhibitors of molecular interactions based on structural information of proteins. poor membrane permeability may be overcome via cell-penetrating peptides, but low stability remains a major drawback. an increase of stability and bioactivity of peptides by coupling to polymers is intended. methods: for the development of peptide-functionalized cell-penetrating polymer conjugates, peptides were coupled chemoselectivly to hpma (n-(2hydroxypropyl)methacrylamide, average mw 28.5 kda), as an inert backbone polymer by native chemical ligation. hpma is water soluble and its capacity in drug delivery has been demonstrated. peptide-functionalized polymers and free peptides were incubated with proteases or cell lysates and proteolytic break-down was determined by fluorescence correlation spectroscopy (fcs) deriving information on the number and size of fluorescent particles based on temporal fluctuations of a fluorescence signal caused by diffusion of particles through a femtoliter-size confocal detection volume. the diffusion time depends on molecular size. therefore this technique is suited for the detection of proteolytic fragments. results: efficient chemoselective conjugation of unprotected fluorescein-labelled peptides was accomplished by means of native chemical ligation. our fcs investigations revealed that conjugation of peptides to hpma increased their biostability. this data also indicate that this effect is peptide-dependent. a proapoptotic peptide coupled to hpma and introduced into mammalian cells by electroporation retained its bioactivity. cofunctionalization of hpma with this peptide and nonaargine yielded an efficient cellular import. macrolides, a rather large group of natural or semi-synthetic antibiotics, are widely known translation inhibitors whose structure is based on 14-16-member lactones with carbohydrate substitutes attached. macrolides bind to ribosomal tunnel (rt) in a way that their lactone ring is located orthogonally to the long axis of the rt, covering most of its cleft. carbohydrate residues of the macrolides are spread along the walls of the rt. hence, the mechanism of protein synthesis inhibition by macrolides relies on the mechanical obstruction they provide to the passage of nascent polypeptide chain through the rt. the goal of this study was to design and obtain peptide derivatives of macrolides interesting both as antibacterial agents and potential probes for investigation of nascent peptide chain topography in the rt. tylosin ( in order to reach target sites inside the cns, neurotherapeutic candidates must overcome the blood-brain barrier (bbb). while several transport mechanisms occur at the bbb, this work has focused on the passive diffusion mechanism. the prediction of a peptide's ability to cross the bbb is not a simple task; hence there exists the need for the rational study of the relevant factors that affect the movement across this physiological barrier. here we present two new approaches based on in vitro non cellular assays for this type of studies. firstly, the evaluation of compound mixtures on parallel artificial membrane permeability assays (pampa). this approach increases the throughput of the study and structure-activity relationships can be easily establish. secondly, the transport and biological activity evaluation in a single assay. this second approach has been applied to the search of inhibitors for cns proteases involved in different neurological diseases (such as prolyl oligopeptidase for schizophrenia) able to cross the bbb. these two new approaches allow assaying compound's permeability in the early stages of a drug development project, and then designing novel analogues with improved bbb transport properties or using blood-brain-barrier shuttles for their delivery. two newly synthesized compounds are derivatives of l-valin and are positional isomers of nicotinic (m-6) and isonicotinic acid (p-6). these functional groups, as well as established good lipid solubility suggest that the main target for their biological action probably will be central nervous system. the presence of aminoacid l -valin, supposes their low toxicity, confirmed by our earlier experiments. the aim of the present work is to study their pharmacological activity as putative drugs. methods: male albino mice (18-20g, 10 in groups) were used. next neuropharmacological parameters were studied: analgesic effect (acetic acid test), neuromuscular coordination (rota-rod test), orientation ("hole board" test) and learning and memory (passive avoidance-step down test). results: significant analgesic effect of both compounds was established (more pronounced by dose 250 mg/kg i.p.). slight depressing effect on the orientation reactions in animals was registered, but the neuromuscular coordination and locomotor activity of treated animals were not changed. good dose-dependent effect on learning and memory was established and м-6 had stronger effect than р-6. the compounds modified the effects of some model substances with central nervous activity. hexobarbital sleeping time was significantly prolonged by p-6, but was antagonized by m-6. pentileneterazole threshold was increased significantly and suggests some anticonvulsant activity of both compounds. conclusion: as positional isomers m-6 and p-6 demonstrated some variations in their pharmacological activity probably due to the differences in their kinetics, metabolism and excretion. registered significant neuropharmacological activity, accompanied by low toxicity motivates the new synthesis and future experimental studies. the glyproline family of regulatory peptides includes pro-gly-pro, gly-pro, pro-gly and also the simplest peptides with hyp substituted for pro. a distinctive feature of these peptides is that they exhibit a broad spectrum of biological activities: the antiulcer activity, the inhibition of blood clotting and thrombosis, the reduction of degranulation activity of mast cells, and the normalization of stressogenic behavioral disorders. alzheimer's (ad) and parkinson's (pd) disease are progressive neurodegenerative disorders which are characterized by amyloid plaques. the main components of the plaques are β-amyloid peptides (aβ1-40 and aβ1-42) and α-synuclein. we have previously shown that small peptides structurally related to the sequence of aβ(1-42) protect against the neurotoxicity of aβ peptides. recent studies by other groups have shown that β-synuclein can counteract the aggregation of α-synuclein in the neurodegenerative process of pd, hereby might protect the central nervous system from the neurotoxic effects of alpha-synuclein. it was found that a tetrapeptide (kegv) protected against the neurotoxicity of aβ peptides in vivo. based on the previous findings, the following sequences of β-synuclein have been synthesized: kegv-nh2 and kegv-oh. after comparing the sequences of α-and β-synuclein, we found common sequences which are keqv, regv, kqgv, keqa. we have synthesized these tetrapeptides in amide forms at their c-termini. the peptides have been synthesized on mbha resin using a manual solid phase peptide synthesis equipment and boc-chemistry. the neuroprotective effects of peptides have been investigated in vitro in mtt test in differentiated neuroblastoma cell culture (sh-sy5y) and in electrophysiological test on rats using multibarrel electrodes in vivo. the neuroprotective peptides might stop neuronal death and can influence ad and pd progression. the present study was carried out to determine antinociceptive effect in vivo of plant peptide hormone phytosulfokine-alpha (h-tyr(4-so3h)-ile-tyr(4-so3h)-thr-gln-oh ) (i) and its selected analogues, such as h-phe(4-no2)-ile-tyr(4-so3h)-thr-gln-oh (ii), h-d-phe(4-so3h)-ile-tyr(4-so3h)-thr-gln-oh(iii), h-tyr-ile-tyr(4-so3h)-thr-gln-oh(iv), h-tyr(4-so3h)-ile-tyr-thr-gln-oh(v) and h-tyr-ile-tyr-thr-gln-oh (vi) in rats. peptides were injected into the lateral brain ventricle at the dose of 100 nmol. in the preliminary investigation we found the psk-as well analogues ii and iii induced a significant antinociceptive effect determined in the test of hot plate. the probable mechanism of this effect was discussed. a.b. bozhilova-pastirova 1 , b.a. landzhov 1 , p.v. yotovski 1 , e.b. dzambazova 2 , a.i. bocheva 2 the tyr-mif-1 family of peptides (tyr-mif-1`s) includes mif-1, tyr-mif-1, tyr-w-mif-1 and tyr-k-mif-1, which have been isolated from bovine hypothalamus and human brain cortex. all these peptides interact with opioid receptors and in addition bind to non-opiate sites specific for each of the peptides. data in the literature suggest that tyr-mif-1`s have antiopioid and opioid -like effects. we used wistar rats to study distribution and density of the tyrozine hydroxylase (th) imunoreactive fibres and nadph-d reactive neurons in the rat ventral and dorsal striatum. our results showed that neuropeptides mif-1 and tyr-mif-1 may affect them. opioid peptides have been recognized as modulators of reactive oxygen species (ros) in mouse macrophages and human neutrophils. data in the literature suggest that peptides of the tyr-mif-1 family -mif-1 and tyr-mif-1 have antiopioid and opioid -like effects. these neuropeptides are isolated from bovine hypothalamus and human brain cortex. so far no data about direct scavenger properties of tyr-mifs peptides were available. in this study we tested the hypothesis that they may scavenge ros in vitro. the antioxidant activity of these two substances was studied in the concentration range of 10-6 -10-4 mol/l. we investigated the luminol-dependent chemiluminescence to test their ability to scavenge the biologically relevant oxygen-derived species: hydroxyl radical, superoxide radical, hypochlorous acid in vitro. we found that tyr-mif-1 was a powerful scavenger in all tested systems. the effects were higher for hypochlorous anion and weaker for superoxide radical. mif-1 had no scavenge activity against the hydroxyl and superoxide radicals and showed a moderate scavenger effect on hypochlorous anion. we have compared different strategies to increase the immunogenicity of an antigenic hiv peptide as a vaccine candidate. our selected b-cell epitope comprises 15 amino acids (317-331) of the v3 region of hiv-1, jy1 isolate (subtype d), and is in tandem with a t-helper epitope corresponding to the 830-844 region of tetanus toxoid. several presentations, including oligomerization, map dendrimer, conjugation to dextran beads or to other macromolecular carriers, have been synthesized and evaluated. murine sera from the different presentations of the v3 epitope have been compared with regard to antibody titers and cross-reactivity with heterologous hiv subtypes. the map dendrimer version of the peptide, conjugated to recombinant hepatitis b surface antigen protein, was a better immunogen than the dendrimer alone, and showed higher immunogenicity than other multimeric presentations, or than the peptide alone conjugated to dextran beads. the map dendrimer version, either alone or conjugated to hbsag, enhanced cross-reactivity towards heterologous v3 sequences relative to monomeric peptide. group a streptococcus (gas) responsible for critical diseases (eg. acute rheumatic fever and rheumatic heart disease) are classified over 100 serotypes according to their surface virulence m proteins. development of vaccine to prevent infection with gas is hampered by the widespread diversity of circulating gas strains and m protein serotypes, and multivalent vaccine strategy would contribute to prevention against various gas infections and provide better protective immunity. we have studied the efficacy of incorporating four different epitopes derived from gas m protein into a single synthetic lipid core peptide (lcp) construct, in inducing broadly protective immune responses against gas following parenteral delivery to mice. peptide vaccine was synthesized on mbha resin by manual spps in situ neutralization/hbtu activation in boc-chemistry. immunisation with the mono-or multi-epitopic lcp vaccine led to high titers of antigen-specific systemic igg responses, and the production of broad protective immune responses as demonstrated by the ability of immune sera to opsonise multiple gas strains. systemic challenge of mice after primary vaccination showed that mice were significantly protected against gas infection in comparison with control mice demonstrating that vaccination stimulated long-lasting protective immunity. these data support to the usefulness of lcp system in the development of synthetic multiepitope vaccine to prevent gas infection. glycoprotein d represents a major immunogenic component of the virion envelope of herpes simplex virus and able to induce high titres of neutralizing antibodies. one of its optimal epitopes is the 9-22 region (9lkmadpnrfrgkdl22). several cyclic peptides possessing thioether bond and different ring size have been already prepared and some of them were conjugated with tetratuftsin derivative (ac-[tkpkg]4-nh2) by thioether bond formation using selectively removable cys protecting groups. antibody recognition results suggested that the size of the cycle has considerable influence on antibody recognition, however, the replacement of met in position 11 by nle is permitted. conjugation of cyclic peptide might increase the antibody recognition, but the binding depends on the structure and/or conjugation site of the cyclic peptide. conjugate with the best binding capacity (7.2 pmol/100ul) as well as the conjugate containing the linear (9-22c) epitope (0.7 pmol/100ul) were selected for immunization. in order to increase the production of antibodies a new group of conjugates was prepared. in these constructs promiscouos t cell epitope peptide derived from tetanus toxoid (ysyfpsv) was attached to both amino groups of lysine residue coupled to the n-terminus of the carrier (ac-ysyfpsv-k(ac-ysyfpsv)-[tkpk(clac)g]4-nh2). the cys containing linear and cyclic epitope peptides were conjugated to the carrier in solution (0.1m tris buffer, ph 8). this work was supported by grants of the spanish-hungarian intergovernmental program and cost chemistry action. background. primary hyperparathyroidism (pht) is characterized with increased parathyroid hormone (pth) secretion and in 70% of pht patients with hypertension. it was previously shown that pro-analogue of pth with a reversed sequence (which include strong alkali sequence -arg-lys-lys-) induced significant hypertensive response at dose 10-10m/kg b.w. one of the hypothesis attributed hypertension in pht patients to the presence of fragments of degraded pth possessing -arg-lys-lys-sequence. aim. to compare influence on mean arterial blood pressure (map) of analogue of 25-34 pth fragment (amide) and 25-34 fragment of pth, with -arg-lys-lys-sequence and also responsible for binding to pth receptor. methods. chosen peptides were synthesized manually by a solid phase peptide synthesis method. the purity of the products was tested by reversed-phase high performance liquid chromatography. the synthesized peptides showed the right molecular mass. the influence on map of synthesized peptides was tested in wistar rats. sequential increasing boluses of each peptide: 10-10, 10-9 and 10-8m/kg.b.w. in the same animal were given i.v. blood pressure was measured continuously in carotid artery. results. injection of synthesized analogue of 25-34 fragment of pth does not show influence on map vs. control group. synthesized 25-34 fragment of pth increased map in 92min. of experiment for 12mmhg ± 3mmhg vs. time of administration of first dose and for 17mmhg vs. control group. conclusion. it seems to be possible, that in case of alternate degradation of pth, accumulation of 25-34 fragment of pth may partially play role in the mechanism inducing hypertension in pht patients. biologically active domains of a high affinity receptor for ig е (fcεri) were determined, the fragments 111-114 and 111-117 of the receptor. the program of research of biological properties of synthesized tetrapeptide rnwd and heptapeptide rnwdvyk included the study of their binding with ige, which was contained in standard solutions and in patients' blood serum. the binding of peptides with ige was explored by the ifa method using ige antibodies labeled with horse-radish peroxidase (hrpo). peptides in the concentration of 100 mkg/ml were used for sorption on immunological plotting boards. higher correlation between the ige concentration and the optical density of the solution after introducing monoclonal antibodies labeled with hrpo and substrate chromogenic mixture (r=0.99) was found in the diagnostic system with sorption rnwdvyk-peptide than in the diagnostic system with sorption rnwd-peptide (r=0.94). similar investigations were conducted with the diagnostic systems with sorption rnwd and rnwdvyk peptides, but rwnd peptides conjugated with hrpo were used as antibodies against immunoglobulin e, instead of hrpo-labeled monoclonal antibodies. almost equal correlation was found between the concentration of ige in standard serum and serum of allergy patients with the known concentration of ige and the optical density of the solutions after introducing the rnwd peptide, conjugated with hrpo. after introducing allergy patients' blood serum in the holes on the plotting board, the heptapeptide bound 23.79% more ige than the tetrapeptide. our experiments demonstrated a high ige binding activity of synthetic rnwd-and rnwdvyk-peptides. in this study, the information spectrum method (ism) of the ha1 subunit of the h5 hemagglutinin protein of the influenza virus, h5n1, of different reference isolates was performed in order to identify possible antigenic determinants resistant to virus mutations. results of this analysis demonstrated that the primary structures of ha1 subunit of h5 hemagglutinins encode a common information corresponding to one characteristic frequency in their iss, which is probably important for the biological function of these proteins, including their possible recognition by the immune proteins targeting this molecule. besides, comparison of the iss of ha1 proteins of h1 "spanish flu" and h5n1 isolates demonstrated an informational similarity between them. based on these results, a segment of the n-terminus of ha1 h5n1 was identified to play a crucial role in the inhibitory and immunological properties of all possible h5n1 variants. the identified core segment, being highly conserved in all h5 strains, was selected as an antigenic determinant and coupled to the sequential oligopeptide carrier (socn), (lys-aib-gly)n, to the lys-nεh2 groups, in order to develop a diagnostic immunoassay and formulate a vaccine candidate for the highly pathogenic h5n1 influenza virus. background and aims: thrombin plays a key role in various disorders such as arterial thrombosis, atherosclerosis, restenosis, inflammation and myocardial infarction. insights into the way in which thrombin interacts with its many substrates and cofactors have been clarified by crystal structure and site-directed mutagenesis analyses, but until recently there has been little consideration of how its non-proteolytic functions are performed. we investigated cardiovascular effects of seven modified proline-and rgd-containing peptides designed from three surface-exposed sites of prothrombin, corresponding to residues 218-223, 332-347, and 445-454. methods: cardioprotective effects of synthetic peptides were tested on the two rat models of heart failure produced by coronary artery occlusion (10-or 45-min) and reperfusion (30-or 240-min). arterial blood pressures from left carotid artery, heart rate and ecg ii standard lead were measured throughout experiment. at the end of second experiment hearts were morphologically investigated by light microscopy and electron microscopy methods. results: on animal model with short-term ischemia investigated peptides did not protected from myocardium ischemia during occlusion, however, tp-l13, bk-mc and tp-h7 protected rat hearts from ventricular fibrillation, contributed more significant functional recovery during reperfusion and raising survival rate. on the model with prolong ischemia, acceptable cardioprotective effect revealed tp-h7 and bk-mc. these peptides significantly diminished necrotic zone of left ventricle, protected hearts from ischemia-reperfusion induced functional and morphological changes. conclusions: investigated proline-containing peptides revealed activity on cardiovascular system -decreasing of blood pressure, cardioprotective properties and improved recovery from ischemia. r. mansi, d. tesauro, c. pedone, e. benedetti, g. morelli the widespread use of compounds containing the gamma-emitting radionuclide 99mtc in nuclear medicine for the scintigraphic imaging, as well as the recent introduction of the beta-emitting radionuclides 188re and 186re in radiotherapy, have led to a rapid development of their chemistries, in order to produce novel radiopharmaceuticals. we have developed new peptide based radiopharmaceuticals based on a scaffold in which the radioactive metal ion is complexed by two different peptides that are able to bind two target receptors (see figure) . the 3+1 mixed-ligand approach has been used for the preparation of neutral oxotechnetium(v) and oxorhenium(v) peptide complexes. the complex preparation requires the simultaneous action of a dianionic tridentate ligand and a monoanionic monodentate thiolato on a suitable metal precursor. the dianionic tridentate ligand is based on the snn donor set able to stabilize the metal complex. the chelating agent (hsc(ch3)2conhch2ch(co-r)nh2) was coupled step by step to a bioactive peptide synthesized on solid phase. the second ligand, based on monodentate thiolato moiety, was coupled on n-terminus of the second peptide. labelling procedures and biological tests on tumour cells overexpressing receptors are described for 99mtc(o) complexed by cck8 and octreotide peptide derivatives. background: endostatin inhibits the proliferation of endothelial cells and induces their apoptosis. the measurement of serum endostatin can predict tumor vascularity. tumor angiogenesis is a strong prognostic factor in patients with hepatocellular carcinoma(hcc). significantly high levels of endostatin were noted in patients with trabecular-type tumors , and with hepatitis infection. methods : 20 patients with hcc, 16 patients with git malignancies, 8 patients with liver metastasis and 8 without metastasis, and 10 normal persons . all subjects were tested for alfa-feto protein (afp) , ca19.9 , carcinoemberyonic antigen (cea), and endostatin by elisa results : endostatin in normal control persons was 47.5 ± 14.22 ng/ml with a significant elevation (p< 0.001) between the hcc group and all the other tested groups .afp was 1.9 ± 0.98 ng/ml in normal persons with a significant elevation between hcc and all the other tested groups ( p< 0.01). ca19.9 was 8.14 ± 1.89 u/ml in normal persons with a significance elevation ( p< 0.01) relative to hcc., and a significance of ( p< 0.001 ) relative to git cancers with metastases. cea was tested to be 1.12 ± 0.71 µg/l in normal persons , and had a significance of ( p< 0.001) relative to git metastases. endostatin was elevated in 2 of 8 patients with git cancers not proved to have metastasis. conclusion : endostatin can be used to denote metaplasia and can also detect possibilities of metastasis or liver cell affection even before the frank development of metaplasia affibody® molecules are a novel class of affinity proteins which are generated by combinatorial engineering of the 58 aa three-helix bundle scaffold, originating from the b domain of staphylococcal protein a. we have used fmoc/tbu chemistry for total chemical synthesis of the affibody zher2:342, binding with picomolar affinity to the cell surface receptor her2. the synthetic protein was investigated for molecular imaging of her2-overexpressing tumours. in vivo detection of her2 in malignant tumours provides important diagnostic information which may influence patient management. to enable gamma camera imaging of the tumours, a panel of potential 99mtc-chelating sequences was designed and introduced into the affibody. the well-studied tc-chelating sequence mercaptoacetyltriglycyl (mag3) was compared to serine-containing sequences with increased hydrophilicity, such as mercaptoacetyltriserinyl (mas3). the total synthetic yield was 14-16 % and the her2-binding affinity of the affibody conjugates were all in the range 200-400 pm. binding specificity of tc-labelled affibody molecules was determined on her2-expressing skov-3 ovarian carcinoma cells. all variants showed receptor-specific binding. the tumour-targeting properties were studied in skov-3 tumour-bearing nude mice. all conjugates demonstrated high tumour uptake, quick blood clearance and low uptake in most other organs. the biodistribution results further showed that the more hydrophilic, serine-containing chelators resulted in a reduced hepatobiliary excretion, which significantly decrease the background in the abdomen area and provide for more sensitive detection. gamma camera images of mice with grafted tumours showed clear visualization of her2-expressing tumours using the 99mtclabelled mas3-affibody conjugate, suggesting a potential future application of this agent for diagnostic imaging. antimicrobial peptides are molecules with a unique mechanism of action. they are widespread in nature and play the role of an effective weapon of innate immune system against bacteria, fungi and viruses. the purpose of this study was to investigate the in vitro activity of natural antimicrobial peptides: citropin, piscidin, protegrin, temporin, uperin and the analogues of antimicrobial peptides: iseganan, pexiganan and omiganan. the peptides were synthesized using the solid-phase method and purified by high-performance liquid chromatography. the peptides were subjected to microbiological tests [mic (minimal inhibitory concentration) and mbc (minimal bactericidal concentration)] on reference strains of bacteria, according to the procedures outlined by the national committee for clinical laboratory standards (nccls). for comparison, conventional antibiotics (vancomycin, rifampycin, piperacillin, chloramphenicol) were included in this research. both the natural antimicrobial peptides and the analogues inhibited the growth of bacteria, but at higher concentrations than did conventional antibiotics. nevertheless, both natural origin of antimicrobial peptides and their low toxicity constitute a considerable advantage and this is an argument for considering the antimicrobial peptides as good candidates for medicines. the linear hexapeptide cypate-grdspk (compound 1; the cypate moiety is a near-infrared fluorescent label) whose rgd sequence was rearranged to grd showed high uptake in the αvβ3 integrin-positive tumor tissues in vitro and in vivo. despite low affinity of 1 to the integrin in the binding assays, the uptake was inhibited by equimolar amounts of the cyclic peptide c(rgdfv), which possesses high affinity to αvβ3 integrin. these observations led to hypothesis that cell internalization of compound 1 may be mediated mostly by only one of the integrin subunits, as the β3 one. indeed, blocking of αv integrin by the specific antibody did not inhibit the internalization of 1 in tumor cells, which was in the contrast with successful blocking the cell internalization by the anti-β3 integrin antibody. similar results were obtained in immunocytochemical assays employing the anti-αv and anti-β3 integrin antibodies. also, studies utilizing the β3-knockout and wild-type mouse cell lines demonstrated that deletion of the β3 subunit markedly decreased internalization of compound 1 in the β3knockout cells. the preferential interaction of compound 1 with the β3 subunit of integrins relative to the αv subunit was supported also by molecular modeling studies. summarizing, the bulk of our experimental and modeling data emphasizes interaction with the β3 integrin as the primary mechanism of the uptake of cypate-grdspk by tumors. since this compound showed the superior biodistribution profile in vivo, our results may provide a strategy to image and monitor the functional status of the β3 integrin in cells and live animals. background and aim: a growing tumor is accompanied by tumor intoxication development. intoxication independs on tumor size and intensity of its break-up. tumor intoxication is one of variant of endogenous intoxication. concentration of tyrosine-contained peptides (tcp) in blood plasma have been proposed as biochemical marker of endogenous intoxication at different organs cancers. our aim was to determine the tcp concentration in blood plasma patients with ovary tumor and its association with the severity of tumor. materials and methods: 178 patients with ovary tumor, mean age is 53 years, were studied. the control group consisted of 20 healthy women without tumor. patients were divided into 2 groups: people with non-malignant and people with malignant ovary tumor. tcp content in blood plasma was estimated by our technique. results: tcp concentration in the control group were 0,32±0,13 mmol. the tested marker was present in increased concentration in blood plasma of the patients with ovary tumor. the mean concentration tcp in patients with non-malignant tumor was 0,53±0,16 mmol. the content of this marker in blood plasma of patients from second group was increased 1,32±0,20 mmol compared with healthy control group. after treatment a significant decrease in tcp content was observed. conclusions: the result indicate that content tcp in blood plasma depends of the type of tumor. it could be suggested that determination of tcp concentration in blood plasma could be useful for improve the diagnostic of ovary tumor and monitoring of its progression. c. strongylis 1 , ch. papadopoulos 1 , k. naka 2 , l. michalis 2 , k. soteriadou 3 , v. tsikaris 1 troponin is a structural protein complex, which is responsible for the regulation of skeletal and cardiac muscle contraction. it consists of three components: troponin i (24kda), troponin c (18kda), and troponin t (37kda), each of which carries out different functions in the striated muscles. cardiac troponins are released into the bloodstream of patients after the onset of a cardiovascular damage. even minimal elevations over the normal values, of serum troponin t and i are being used to diagnose acute myocardial infarction and also to rule out the patients' condition. the development and commercialization of highly specific biological assays for the detection of cardiac troponins is based on the production of specific antibodies against the whole complex or individual subunits. however, the specificity and sensitivity of these assays vary due to problems mainly originated from the fact that cardiac troponins have a high homology with the skeletal isoforms. the aim of this work is to select and synthesize appropriate regions of the cardiac isoforms of troponin i, c and t, suitable for the production of more sensitive and specific cardiac troponin detecting reagents. in order to construct the immunogenic complexes, the selected sequences were conjugated to the tetrameric sequential oligopeptide carrier (soc4), either by the classic solid phase step-by-step methodology or by chemoselective ligation reactions. using the carrier conjugated troponin sequences, anti cardiac troponin complex specific antibodies in high titers were produced. the increasing problems with the reproductive systems of man and animals are recently linked to the presence of polluting chemicals with endocrine activity, the so called endocrine disrupting chemicals or edc's . the family of edc's is a heterogeneous one and consists of natural and synthetic hormones (like estradiol, ethynylestradiol and diethylstilbesterol), phyto-estrogens (like genistein and coumestrol) and industrial chemicals (like bisfenol-a, ftalates and various pesticides). because of the complexity of the environmental matrices and the low physiologically active concentrations of the edc's there is still a need for an efficient routine analysis protocol. we want to develop a solid-phase bound receptor that possesses a high selectivity for edc's and thus can be used in a simple solid-phase extraction protocol. this receptor must have the right functional groups that bind the edc's with a strong affinity and must be able to create a cavity in which the edc's can fit. by looking at nature's own estrogenic receptor for humans we have found the different amino acids responsible for the specific interactions . in order to create the cavity which mimics the behaviour of the hormone-binding domain of the human estrogenic receptor we have made a tripodal scaffold. this tripodal scaffold has three orthogonal protected amino groups that will allow the generation of three independent peptide chains. milk proteins are a source of opioid peptides. these peptides are liberated from milk proteins during enzymatic hydrolysis. some of these peptides are characterized with agonistic (β-casomorphins) and some with antagonistic (casoxins) properties. the aim of the investigations was to determine the presence of opioid peptides with antagonistic properties in milk products. the experimental material included cheeses, yogurts and kefirs. peptides were extracted with a methanol-chloroform mixture (2:1 v/v). the peptide extracts were purified by spe method on c18 or stratax columns and characterized by sds-page electrophoresis. the agonist opioid peptides (casoxins) were identified by hplc using standard agonist peptides. the opioid activity was measured by examining the effects of peptide extracts on the motor activity of isolated rabbit intestine. the results of sds-page electrophoresis indicated the presence of 5 to 9 fractions in peptide extract derived from cheeses and yogurts and 17 to 20 ones from kefirs. the presence of casoxin a (0.22-0.68 µg/mg of extract) was proved in all examined the milk products. lactoferroxin a (0.31-1.88 µg/mg of extract) was identified only in kefirs and yogurts. those products were also found to contain trace amounts of casoxin c. all peptide extracts showed the antagonistic activity in the relation to motor activity of isolated rabbit intestine. the highest antagonistic activity was reported of peptide extract from kefirs (3.62-17 .20%) and gouda cheese (15.68-16.36%), as compared to morphine. the physiological and nutritional function of these antagonist peptides requires elucidation. a. péter 1 , r. berkecz 1 , f. fülöp 2 the past decade has seen a growing interest in β-amino acids, which are important intermediates for the synthesis of compounds of pharmaceutical interest and can be used as building blocks for peptidomimetics. oligomers of β-amino acids (β-peptides) fold into compact helices in solution. recently, a novel class of β-peptide analogues adopting predictable and reproducible folding patterns (foldamers) was evaluated as a potential source of new drugs and catalysts. studies on synthetic β-amino acids can be facilitated by versatile and robust methods for determining the enantiomeric purity of starting materials and products. highperformance liquid chromatography (hplc) is one of the most useful techniques for the recognition and/or separation of stereoisomers including enantiomers. the aim of the present work was to evaluate hplc methods for the separation of enantiomers of eighteen 3-amino-3-aryl-substituted propanoic acids (β-amino acids). direct separations were carried out on different macrocyclic glycopeptide based stationary phases, such as ristocetin a containing chirobiotic r, teicoplanin containing chirobiotic t, teicoplanin aglycon containing chirobiotic tag, vancomycin containing chirobiotic v columns and on a chiral crown ether based column. the effects of different parameters on selectivity, such as the nature of the organic modifier, the mobile phase composition, the flow rate and the structure of the analytes are examined and discussed. the separation of the stereoisomers was optimized by variation of the chromatographic parameters. the efficiency of the different methods and the role of molecular structure in the enantioseparation were noted. the elution sequence of the enantiomers was determined in most cases. a rational approach to evaluating peptide purity a. swietlow 1 , r. lax 2 1 amgen, inc., pharmaceutics, thousand oaks, ca 2 polypeptide laboratories, inc., torrance, ca, usa recent years have seen an enormous increase in interest in peptide therapeutics. new peptide leads are often chosen by screening procedures using microgram to milligram quantities of peptides, frequently provided by specialized manufacturers utilizing automatic synthesizers to maximize output. the purity of the resulting compounds is often not very high. the use of spps synthetic procedures predetermines that most impurities are closely related and difficult to resolve by reversephase purification. these factors, combined with the use of generic analytical methods not specifically optimized for the peptide in question (e.g. the ubiquitous 0.1% tfa/water/acetonitrile system), lead to erroneous results that frequently severely overestimate the purity of the peptide. the use of poorly characterized materials in pharmaceutical development leads to significant risks of obtaining false negative or false positive results that may cause potential leads to be overlooked or misinterpretation of their pharmacological profiles. we describe a rapid, systematic and reliable hplc procedure for evaluation of peptide purity. utilizing the increased separation efficiency by increasing the column temperature and adjusting the gradient in two steps in reverse-phase buffers containing tfa, naclo4, or ion-exchange buffers containing kcl, we demonstrate that methods -suitable for preclinical research -can be developed rapidly. the proposed approach will be illustrated with examples of peptides ranging between 9 and 28 amino acids and a model peptide vypnga. it will be demonstrated that peptides showing an hplc purity close to 100% are often 10 -25% less pure. to approach a high-throughput cell assay format using peptides, we attempt to design and construct a peptide microarray for examination of cell activities of peptides including apoptotic cell death. peptides were immobilized onto solid surfaces via a novel multi-functional linker. the linker enable us to examine various types of peptide cell assays in an array format. we also designed and synthesized peptidyl capture agents on the basis of the cell-active sequences suitable for the peptide microarray. the utility of targeted nanoparticles as fluorescent probes for tissue imaging has recently been subject to widespread interest. one exciting prospect is the further development of nanoparticles conjugated to both targeting peptides and cytotoxic cargoes. these nanodevices could preferentially bind to specific cells and/or tissues to provide effective tools for drug delivery. hence, such multifunctional nanoparticles could provide both diagnostic and therapeutic functions by acting as fluorescent probes that offer targeted delivery of therapeutic agents. we have coated the surface of quantum dots (qdots) with cell-penetrating peptides (cpp) to target and label u251m cells for fluorescence imaging. qdots were initially coupled to polyethylene glycol linkers via carboxyl functionalities on their surface. a heterogeneous mixture of poly-arginine peptides of varying lengths (arg(6)-arg(10)) were covalently coupled via amide bonds to the polyethylene glycol linkers, conferring a cell penetrating capacity to the modified qdots. fluorescence imaging of u251m cells, after incubation with the conjugated qdots at concentrations of 20nm, gave clear signals indicating cell binding and internalisation of the modified qdots across the plasma membrane. we aim to further expand this work by employing racemic mixtures of cpp and cytotoxic agents to engineer conjugates that will facilitate both imaging and the therapeutic delivery of cytotoxic moieties. the ability of cell penetrating peptides (cpp) to deliver biologically active cargoes into different cell types has been successfully applied in several experimental systems. despite the progress and growing number of described cpps, reports about the internalization mechanisms and the intracellular routes of cpps still remain controversial. we have characterized the membrane interaction and cellular localization of proteins delivered into hela cells by cell penetrating peptide transportan (tp) and its shorter analogue tp10 on ultrastructural level. our previous results obtained by transmission electron microscopy showed that complexes of transportans with gold-labeled streptavidin translocated into cells inducing large invagination of plasmamembrane, suggesting the uptake by macropinocytosis. the complexes of transportan with gold-labeled neutravidin, in contrary, were taken into cells mostly via caveosomes and clathrin-coated vesicles. the cell-transduced transportanprotein complexes localized mainly in the vesicular structures of different size and morphology. most of the complexes-containing vesicles in the perinuclear area contained also lamp2 protein, marker of late endosomes and lysosomes. still, the transportan-protein complexes were not confined in the membrane-surrounded vesicles, but spread in the cytosol suggesting the escape of transportan-protein complexes from endosomes. our findings show the involvement of different endocytic pathways in the transportan-mediated uptake process of proteins. the concentration of a cpp and the properties of cargo protein seem to determine the pathway for the cellular uptake of a particular construct. rgd peptides (r = arginine; g = glycine; d = aspartic acid) have been found to promote cell adhesion upon interaction with alphav-beta3 receptors, which are strongly overexpressed during neoangiogenesis by solid tumor associated cells compared to healthy cells. in this study we designed new targeting motifs aimed to deliver various antitumoral drugs specifically to cells involved in tumor vascularization. we inserted this short rgd sequence in tetracyclopeptides closed with various means. we expect these new cyclotetrapeptides to be more specific for the targeted receptor. moreover, these new type of cyclic peptides were multimerized on different scaffold to further improve the receptor avidity. our purpose is first to scrutinize and to quantify the efficient cellular uptake of these molecules and second, to address the specific cell targeting of a fluorescent cargo by differents tools such as fluorescence activated cells sorting (facs) analysis or fluorescence microscopy. these new targeting units were evaluated on two different cell lines: human umbilical vein endothelial cells (huvec) with an over expression of the alphav-beta3 integrin receptor and a549 cells expressing a much lower level of this receptor. preliminary results about the selectivity and the efficacy of these new targeting units will be presented. we have recently developed new approaches for obtaining highly immunogenic peptide conjugates: synthetic polyelectrolytes (pe) were used for the conjugation with peptide molecules in which pe carry out the carrier and adjuvant roles simultaneously. in this study, 4 epitopes of antigenic parts of surface antigen of hepatitis b virus (2-16, 22-35, 95-109 and 115-129 of the s gene.) had been synthesized.the synthesis of peptides was performed by explorer pls ® automated microwave synthesis workstation (cem). peptide conjugates of synthetic anionic polyelectrolytes (copolymers of acrylic asid and n-vinylpyrrolidone) were synthesized by carbodiimide condensation following the modification procedures described early. composition and structure of bioconjugates were characterized by hplc (shimadzu), nanospr-3, zetasizer nano zs, steady state fluorescence spectrometer qm-4 and viscotek tda 302 size exclusion chromatography. it was obtained that a single immunization of mice with pe-peptide conjugates without classical adjuvant increased the primary and secondary peptide-specific immune response to hbsag. moreover, these conjugates possess own selectivity for recognizing the antibody in blood sera of hepatitis virus injected people. tissue engineering requires delivery of transplanted cells to organ sites needing repair/regeneration. we have demonstrated that several active laminin peptide-conjugated chitosan membranes enhanced the biological activity and promoted cell adhesion in a cell-type specific manner. the most active laminin peptide (ag73: rkrlqvqlsirt)-conjugated chitosan membrane could deliver keratinocytes to a wound bed. when human keratinocytes were seeded onto the ag73-chitosan membranes under serum-free condition, more than 70% of the cells attached within 2 hrs. the membranes carrying keratinocytes were stable enough for handling with forceps and were inverted onto the muscle fascia exposed on the trunk of nude mice. keratinocyte sheets were observed after 3 days and colonies appeared after 7 days on the fascia of host mice. these cells were multilayered on day-3 and expressed various keratinocyte markers, including cytokeratin-1, involculin, and laminin ?2-chain. these results suggest that the ag73-conjugated chitosan membrane is useful as a therapeutic formulation and is applicable as a cell delivery system, such as delivering keratinocytes to the wound bed. the peptide-chitosan approach may be a powerful cell transplantation tool for various tissues and organs. the fluorescent semi-conductive (cdse/zns) nanocristals possess very attractive optical properties that could be used for tracking individually biological receptors in vivo. our aim is to design functionalized water-soluble semi-conductive nanocristals (or quantum dots) that interact selectively with lipidic or biological membranes. to valid our approach, the interaction between the decorated qd and giant vesicles were observed by optical fluorescent and dark field microscopies. in view to solubilize and selectively bind fluorescent nanocristals to a lipid membrane, heterobifunctionalized peptidic ligands (liipe) that presented an adhesion domain for the nanocristal surface, an hydrophilic spacer and a terminal recognition function, were synthetized. the colloïdal stability of the water-soluble nanocristals (nc-lipe) was checked by dynamic light scattering, optical and electron microscopies the interaction of grafted nanocristals (nc-lipe) with positive or neutral giant vesicles was observed by optical fluorescence and dark field microscopies. as shown in figure, negatively charged nanocristals (nc-lipe) selectively adsorbed onto the surface of positively charged giant vesicles without altering the morphology of the vesicle. the nanocristals appeared as fluorescent patches growing on the surface of the vesicle until completely recovering. therefore these ligands (lipe) permitted to chemically functionalize the nanocristals by keeping their colloïdal stability and their fluorescence in water. furthermore it was possible to selectively label vesicle membrane. creatine analogues for treatment of obesity: us patent 5 bioactive peptides containing pairs of basic amino acids are rapidly metabolized as a result of cleavage by trypsin-like enzymes. to increase the metabolic stability of opioid peptides containing arg-arg and arg-lys pairs, the arg residues were replaced by homoarginine (har) kenes international leprince 1 , f. cavelier 2 , p. gandolfo 1 , m. diallo 1 , h. castel 1 , l. desrues 1 m304 new bradykinin analogues modified with 1-aminocyclopentane-1-carboxylic acid effect on rat blood pressure and rat uterus o. labudda-dawidowska 1 , d. sobolewski 1 , m śleszyńska 1 , i derdowska 1 synthesis and heparin binding sites identification f. baleux 1 , f. arenzana-seisdedos chemokines are small proteins involved in numerous biological processes (inflammation, immunity, morphogenesis, tissue repair, and tumour development) the general goal of our project is to elucidate the role that hs plays in vivo in the physiologic and pathologic activities of the chemokine cxcl12/stromal derived factor-1, and to characterise the molecular and structural determinants accounting for the interaction. three sdf isoforms, alpha (68 aa), beta (72 aa) and gamma (98 aa) have been identified. we previously identified the major heparin binding site on sdf alpha and demonstrated the importance of hs/sdf interaction in hiv entry cell inhibition (1,2). sdf gamma amino acids sequence corresponds to the sdf alpha sequence extended by a c-ter 30 amino acids sequence containing putative heparin binding sites. in order to determine sdf gamma heparin binding sites, wild type and mutants proteins were synthesised by stepwise solid-phase peptide synthesis using fmoc chemistry prusiner proc. natl. acad. sci here we describe xenome's drug development process for the chi family, conopeptide -mria[1] of the predatory marine snail conus marmoreus, leading to a suitable drug candidate (xen2174). xen2174 is highly selective for the norepinephrine transporter (net) compared to other transporters, such as dopamine and serotonin, and inhibits net via an allosteric mechanism. xen2174 is currently in a phase i/iia clinical trial for the treatment of severe pain. an intensive synthetic analogue and screening program around -mria, incorporating early stage animal data xen2174 isomers were synthesized via selective disulfide bond formation to identify the active connectivity. data from alanine-scans, single amino acid mutations and probing of backbone interactions combined with the full 3d nmr structure, led to the development of a pharmacophore for xen2174. this model is refined from further studies where structure-activity relationships were developed utilising binding and functional assay data for a range of peptides anti-cancer drug design anti-cancer drug design published structural data for hdac-like protein, a bacterial enzyme sharing high homology to the hdacs in its active site, confirmed that this protein contains a zinc in the active site. for the discovery of specific hdac inhibitors, a number of hydroxamic acis and related compounds have been designed based on the ligating function to the zinc atom. the mechanism also involves an appropriate nucleophile in the active site. chlamydocin is a cyclic tetrapeptide on the other hand, we have been focusing the cyclic tetrapeptide to develop the potent and specific inhibitors of hdacs. in the present report, we employed the chlamydocin scaffold and successfully introduced the series of thioether as the functional group to the cyclic tetrapeptide. it is well argued that the strong inhibition of hdac requires the best combination of zinc ligand, capping group, and appropriate spacer between them jerusalem 3 department of biological regulation 4 department of organic chemistry 5 department of biological chemistry, weizmann institute of science, rehovot, israel estrogen has a key role in the regulation of skeletal growth and maintenance of bone mass. the use of estrogen and selective estrogen receptor (er) modulators in treatment of osteoporosis is limited due to substantial risks for breast cancer. recently, we developed peptides having estrogen-like activity peptide emp-1 had no effect on bone growth in normal mice, and did not influence the ovx-induced bone-loss. we then developed a new µct methodology to evaluate uncalcified and calcified growth-plate parameters. in the ovx mice, peptide emp-1 reduced volume and thickness of the uncalcified growth-plate, a possible cause for the inhibition of bone longitudinal growth. based on a reported enhancement of er-in female mice during protein biosynthesis, after the release of the nascent polypeptide chain, ribosome recycling factor (rrf) disassembles the post-translational complex. rrf has been shown to be essential for bacterial growth. thus, we are attempting to design suitable compounds to inhibit the rrf function as candidates for new-type antibiotics. we have determined the structure of rrf with 185 amino acid residues by nmr and x-ray analyses and shown that rrf has two domains domain i with three stranded helical bundles and domain ii with β/α/&beta furthermore, we recently determined the structures of the 70s ribosome-rrf complex by cryo-electron microscopy and the 50s ribosome-rrf domain i complex by x-ray analysis using the results of these experiments, we elucidated the interaction profiles between rrf and ribosome and found that the cationic center consisting of three arginine residues on the surface of the helical bundle, which we have shown to be essential for the activity of rrf, is bound to helix 69-71 of 23s ribosomal rna. we synthesized the rna and peptide fragments around this interacting site and characterized them by physico-chemical analyses. the results of cd and biacore experiments to investigate the details of the interactions between them showed that a 27 mer of rna fragment is bound to rrf biochemistry 42 causes an increase of pain by inhibiting the opioid response [1]. recent research has shown further that melancortin receptors, mainly subtype mc4r, produce an increase in response to pain stimuli [2]. based on this previous work, we are developing chimeric ligands which will be of benefit to therapeutic pain treatment with enhanced opioid efficacy by acting as agonists at opioid receptors and antagonists at both cck and melanocortin receptors cck (i) and melanocortin (ii) pharmacophores were overlapped by trp, and different profiles of opioid pharmacophores (iii) were linked to the n-terminal of the melanocortin pharmacophore (figure). the designed ligands showed moderate to high biological activity at all three receptors depending on their respective structures. design considerations and structure-activity relationships will be discussed in detail along with in-vivo assay results china synthetic exendin-4 is a 39-amino acid peptide that exhibits potent anti-diabetic and dose-dependent glucose-regulatory activity. exendin-4 is susceptible to degradation in plasma, so its activity is limited. our aim is to find sites in exendin-4 that are susceptible to cleavage and provide information for designing new exendin-4 analogues. in this study the stability of exendin-4 in human plasma was evaluated in vitro. exendin-4 was incubated in plasma at 37 ℃, extracted with sep-pak octadecyl columns and subsequently analyzed using high performance liquid chromatography (hplc). the results showed that exendin-4 was slowly broken down in plasma with a half-life of 9.57 h. the degradation products were identified by quadrupole time of flight mass spectrometry (q-tof-ms) with electrospray ionization pharmacology of exenatide(synthetic exendin-4): a potential therapeutic for improved glycemic control of type 2 diabetes one of the proposed solutions for the pharmacotherapy of obesity, a major health problem in the western world, is to regulate the biochemical pathways that control the metabolic balance in the body. the melanocortin pathway regulates energy balance by binding of the catabolic endogenic neuropeptide αmsh to its mc4 receptor and thus causes a decrease in food intake. we have synthesized a backbone cyclic peptide library, based on the minimal αmsh sequence phe6-d-phe-arg-trp9 [1], that activates the mc4 receptor. all the members of the library shared the same sequence analysis using colorimetric liposomes confirmed that bbc-1 penetrate the intestinal cells by the transcellular mechanism. moreover, bbc-1 have high metabolic stability to intestinal enzymes (100% recovery after 5 hr). ec50 analysis showed that bbc-1 selectively binds and activate the mc4 and mc5 receptors (ec50 3.97±0.63 and 7.27±0.40 respectively). oral administration of bbc-1 in mice showed reduces food intake melanocortin tetrapeptides modified at the n-terminus, his, phe,arg and trp positions 2 department of experimental and health sciences graduate school of pharmaceutical sciences 2 graduate school of agriculture 3 graduate school of medicine consisting of 54 amino acids, is a product of the metastasis suppressor gene kiss-1. this c-terminally amidated peptide was identified as the endogenous ligand of an orphan g-protein coupled receptor metastin-gpr54 signaling may regulate gonadotropin secretion and negatively regulate cancer metastasis. it is interesting that activation of gpr54 signaling negatively regulates the function of sdf-1-cxcr4 axis in cho and hela cell transfectants we conducted the structure-activity relationship (sar) study on kisspeptin-10 using the neuropeptide-derived rw-amide scaffold to identify five-residue peptide amides as novel gpr54 agonists equipotent to kisspeptin pro-), where aoe is (2s,9s)-2-amino-8-oxo-9,10-epoxydecanoyl. in continuation of our study to design and synthesize analogues bearing a zinc ligand to develop potent inhibitors of histone deacetylase (hdac) inhibitors, we shifted the aromatic ring of phenylalanine at the aminoisobutric acid (aib) position and also at the imino acid position. the aim is to explore the interaction of cyclic scaffold with the rim of hdac paralogs. we replaced the epoxyketone moiety of aoe with sulfhydryl group, which is protected as disulfide hybrid, as zinc ligand. benzene ring was introduced to aib structure to design amino-1-indane carboxylic acid and amino-2-indane carboxylic acid. aromatic ring-containing imino acids, such as d-tic were also employed to replace d-pro. the cyclic tetrapeptides were profiled by the inhibition of hdac1, hdac4, and hdac6 in adult goats, however, the infection remains unapparent and the virus may cause abortion, vulvovaginitis or balanoposthitis. the use of a vaccine could provide a powerful tool for the control of cphv-1 infection. synthetic peptide-based vaccines have advantages of being selective, chemically defined and safe. in order to further localize immunogenic epitopes, glycoproteins b, c and d of cphv-1 were analyzed with several prediction programs. peptide conjugates incorporating t and b cell determinants in multiple copies in branched architecture are better immunogens for the preparation of goat vaccines, we synthesized peptide conjugates bearing t cell epitope on the n-terminal of the core. b cell epitopes were conjugated via a thioether bond on the ne-amino group of four choroacetylated lysine residues of the core. elisas confirm that the b cell epitopes and the conjugates t celltetratuftsin induce epitope-specific and antibody responses two recorded electrodes implanted bilaterally. eeg recorded after the mirror focus was arises. trh applicated intranasal in ultra low doses (10-9 m and 10-12 m) or intravenously in high doses (25mg, 50mg, 100 mg). for eeg registration and analysis the computer system conan was used and new modification of fractal analyze of quantized eeg. results: the synchronization of epileptic activity between primary and mirror focuses observed on the third day after operation. intranasal application of trh induced reduction of spontaneous focal epileptic activity as in primary cobalt damage focus as in the mirror focus more than 1h. the inhibition of mirror focus was more expressed. quite the contrary intravenous trh administration provocated the epileptic discharges in both local focus. the intense synchronized generalized activity was record during 30-40 min deraos 1 , t.v. tselios 1 , i. mylonas 2 , g.n. deraos 1 it is known that cyclic peptides are more stable in enzymatic degradation and conformationally restricted compared to linear. the cyclization was achieved using o-benzotriazol-1-yl-n,n,n',n'-tetramethyluronium tetrafluoroborate (tbtu) and 1-hydroxy-7-azabenzotriazole, 2,4,6 collidine allowing fast reaction and high yield final product. the purification was achieved using reversed phase high performance liquid chromatography (rp-hplc) and the peptide purity was assessed by analytical hplc and mass spectrometry (esi-ms). the synthesized cyclic plp analogue was found to exhibit lower agonist eae activity compared to linear plp139-151 epitope in sjl/j mice. this implies that the conformation of cyclic analogue does not trigger autoimmune reaction in the central nervous system and therefore encephalomyelitis the netherlands 3 department of experimental and health sciences on the other hand, in both central and peripheral nervous system, cck acts as neurotransmitter. recently, cck is focused at modulation effects on feeding especially. in this study, we tried to establish a sensitive and specific enzyme immunoassay (eia) for detecting cck and to investigate the effect of some dopamine receptor antagonists using this eia, we measured plasma cck-like immunoreactive substance (is) levels in five healthy human subjects after single oral administration of some prokinetics. the minimum amount of cck detectable by our eia system was 2.0 pg/ml, and the ic50 of the calibration curve was 75 pg/ml. we revealed that domperidone and itopride caused significant decreases in plasma cck-is levels but metoclopramide and sulpiride did not. we established a sensitive and specific eia for cck. furthermore pro-pro-phe-phe-), isolated from linseed oil [1], possesses a strong immunosuppressive activity comparable at low doses with that of cyclosporin a [2]. it has been postulated that the tetrapeptide sequence pro-pro-phe-phe is important for biological activity of cla on the basis of this information we have synthesized a series of cla analogues in which the alpha-proline residue was replaced by beta2-iso-proline and beta3-homo-proline residues, respectively (fig.1). the synthesis of titled beta-amino acids has been achieved according to the literature procedure italy synthetic peptides are largely used as antigens in solid-phase immunoenzymatic assays (elisa) for recognition of antibodies (abs) in biomedical research and, most importantly, in the set up of diagnostic methods. it is well known that the method of peptide immobilization on the solid support is very important for a correct ab recognition atherosclerosis in patients infected with helicobacter pylori (hp) we synthesized appropriate oligopeptides immobilized on cellulose via n-or c-termini, using standard -alanine linkers as well as a new linker, developed for this particular studies glc)ghsvflapygwmvk) we found the strongest recognition when the peptide was linked to the cellulose support via the c-terminus. however, in the case of ureb f8 hp urease smallest epitope (sikedvqf), and epitope ub-33 (321-339 hp fragment: chhldksikedvqfadsri) the strongest reactions with sera of atherosclerosis suffering patients were obtained for n-terminally anchored peptides the synthetic dipeptide gamma-d-glutamyl-l-tryptophan (scv-07) has been shown to stimulate t-lymphocyte differentiation and specific immune responses, and enhance il-2 and inf-gamma production. due to this preferential activation of th1 cytokine production, scv-07 may show utility in treatment of infectious diseases cba mice at a dose of 2,500 µg/kg. the same animals were used for all three methods of administration with a dosing interval of 2 weeks. blood samples were taken from the right retro-orbital sinus. for determination of the scv-07 concentration in blood samples, an "eia-scv-07" competitive solid-phase immuno-enzyme assay was developed (loq 20 ng/ml) with a mean residence time of 10 minutes. 5 minutes postdose, indicating very rapid absorption. mean concentrations then declined and were measurable through 1.5 and 3 hours postdose (mrt 20 and 50 minutes, for i/p and p/o, respectively). the estimated bioavailability of scv-07 after i/p and p/o administration was almost equivalent gastrin-17 (g17) is a peptide which promotes gastric acid secretion, cell proliferation, and occasionally gastrointestinal cancer in the gastric antrum. g17 also promotes the growth of cancerous colonic epithelial cells, but the cck2/gastrin receptor, which mediates its activity, is largely not expressed on such cells. instead, our previous studies have shown that some other receptor mediates stimulation of proliferation of dld-1 and ht29 human colonic carcinoma cells by ncarboxymethyl gastrin (g17gly) at namomolar concentrations and inhibition at micromolar concentrations, indication separate binding sites. we have shown previously that g17(1-12)-oh stimulates cell proliferation of ht-29 cells -6)-nh2, in order to determine their selectivity for and activation of the putative proliferation-stimulatory receptor. the results revealed that g17(1-12)-oh is not selective for a single receptor, but binds both sites as do g17 and g17gly. g17(1-6)-nh2 promotes dose-dependent and non-biphasic proliferation of dld-1 cells and binds a single receptor with low affinity. m484 comparative study of ige-binding activity of synthetic peptides rnwd and rnwdvyk v th486 involvement of l-name in the antinociceptive effects of newly synthesized analogues of tyr-mif-1 peptide in rats tyr-mif-1 is able to interact with opioid receptors with a higher potency at m sites as well as to its specific non-opiate receptors in the brain. nitric oxide and tyr-mif-1`s are potent modulators of opioid activities. involvement of no in nociceptive effects is well documented in various physiological and pathological processes in the cns. l-name when administrated i.c.v. or systemically exhibit antinociceptive activity in rats as evaluated by the pp test. in the present study, we investigated the involvement of l-name in the antinociceptive action of newly synthesized analogues of tyr-mif-1 peptide: nα-(me)tyr-mif-1, d-tyr-(me)-mif-1, tyr(cl2)-mif-1 and tyr(br2)-mif-1. the experiments were carried out on male wistar rats (180-200 g). the changes in the mechanical nociceptive greece paclitaxel is one of the most important anticancer drugs used mainly in treatment of breast, lung, and ovarian cancer and is being investigated for use as a single agent for treatment of lung cancer, advanced head and neck cancers, and adenocarcinomas of the upper gastrointestinal tract. however, the development of resistance to paclitaxel, the side effects and low solubility of this drug remain major obstacles for its optimal use in the clinical practice. in this work, we present the synthesis of various analogues in which paclitaxel is covalently bound to peptides or as multiple copies to synthetic carriers. these peptide-paclitaxel derivatives possess greater solubility in water, could be suitable in producing anti-paclitaxel antibodies and inhibit the proliferation of human breast, prostate and cervical cancer cell lines. although, no major differences were found concerning the extent of the antiproliferative effect between various paclitaxel derivatives and paclitaxel, the analogue with four molecules of paclitaxel covalently bound to synthetic carrier [ac-(lys-aib-cys)4-nh2] when used at low concentrations inhibited cell proliferation more potently than paclitaxel th489 involvement of the histaminergic system in the nociceptin-induced pain-related behaviors in the mouse spinal cord the purpose of the present study was to determine whether histamine-containing neurons in the spinal cord are involved in nociceptin-induced behaviors in mice. the i.t. injection procedure was adapted from the method of hylden and wilcox. immediately following the i.t. injection, the time spent for nociceptive behaviors including scratching, biting and licking were measured. the i.t. administration of nociceptin resulted in nociceptive behavioral responses, which were eliminated by the i.t. co-administration of opioid receptor like-1 (orl-1) receptor antagonists. the nociceptive behaviors were significantly attenuated by the i.t. co-administration of the h1 receptor antagonists, but not the h2 receptor antagonists. i.t. co-administration of the h3 receptor antagonist significantly increased the behavioral responses, whereas the behavioral responses were completely attenuated by the i.t. co-administration of the h3 receptor agonist. an antiserum against histamine injected i.t. reduced the nociceptin-induced behavioral responses. the same result was observed by i.p. pretreatment with histidine decarboxylase inhibitor. in conclusion, i.t.-administered nociceptin elicits the orl-1 receptor-mediated nociceptive behavioral responses. the activation of the orl-1 receptor by nociceptin may induce the release of histamine in previous studies, we demonstrated that highly constraint cyclic (s,s)-cxaac-containing peptides inhibit platelet aggregation and fg binding [1,2]. cyclization reduces the allowed conformations, of both the backbone and the side chains, and possibly induces a favourable for the biological activity orientation of the charged side chains. conformational studies revealed that orientation of the charged side chains toward the same side of the molecule increase the anti-aggregatory activity of the inhibitor. in this work we present the synthesis and the inhibitory activity of new cyclic compounds. for the design of the studied compounds we combined the available information from the -cdc-containing inhibitors and the gpiib 313-320 (ymesradr) sequence which has been shown to inhibit the adp induced human platelet activation however, its pharmacological effects and physiological functions are still unclear. the present study was designed to characterize the nociceptive behaviours induced by intrathecal (i.t.) administration of hk-1 in mice. the i.t. administration was made in conscious mice according to the method described by hylden and wilcox. immediately after the i.t. administration, the accumulated time for nociceptive behaviours was measured for 10 min. the i.t. administration of hk-1 dose-dependently produced characteristic nociceptive behaviours consisting of scratching, biting and licking, which peaked at 0-5 min and almost disappeared by 15 min after injection. the subcutaneous pretreatment with morphine dose-dependently attenuated the hk-1-induced nociceptive behaviours. the nociceptive behaviours elicited by low-dose of hk-1 were significantly inhibited by i.t. co-administration with nk1 receptor antagonist, however, the nociceptive behaviours elicited by high-dose of hk-1 were not affected by i.t. coadministration with nk1 receptor antagonist. on the other hand, nmda receptor antagonists significantly suppressed both high-and low-doses of hk-1-induced nociceptive behaviours in a dose-dependent manner. these results suggest that the nociceptive behaviours induced by low-dose of hk-1 may be mediated through both nk1 and nmda receptors, whereas high-dose of hk-1 may induce the nociceptive behaviours through nmda receptor the bacterial lp are strong modulators of the innate immune system. until recently, it was generally assumed that triacylated lp, like the synthetic pam3cys-sk4, are recognized by tlr2/tlr1 heteromers, whereas diacylated lp, like fsl-1, induce signalling through tlr2/tlr6 heteromers. contrary to this model, we could show that depending on the peptide moiety, diacylated lp also signal in a tlr6-independent and tlr1-dependent manner. the aim of this study was to analyse more closely the structural basis of this heteromer usage. the synthesis of lp was carried out by fully automated solid phase peptide synthesis and fmoc/tbu chemistry on tcp or rink amide resin. information on the structural factors determining the tlr2/tlr1 versus tlr2/tlr6 heteromer usage was obtained by testing of ligands with cells obtained from tlr2 , tlr6 , and tlr1-deficient mice. when stimulating b-lymphocytes of wild-type mice we found that ester-bound long-chain fatty acids are necessary to induce considerable responses. for triacylated lp with long chain length ester-bound acyl residues (like pam3c-ssnask4) the response in tlr1-deficient cells was only slightly decreased, whereas for lp with short length ester-bound fatty acids (like pamoct2c-ssnask4) the response was completely abolished. in summary, a tri-acylation pattern is necessary but not sufficient to render an lp tlr1-dependent and a di naples 2 department of organic chemistry "ugo schiff sera from patients suffering from autoimmune disorders often contain multiple types of autoantibodies, some of which can be exclusive of a disease and thus used as biomarkers for diagnosis. identification of these autoantibodies, as disease biomarkers, should be achieved using native antigens in simple biological assays. however, post-translational modifications, such as glycosylation, may play a fundamental role for specific autoantibody recognition. in line with these observations, we previously described synthetic glycopeptides able to detect high autoantibody titers in sera of patients affected by multiple sclerosis, an inflammatory, demyelinating disease of the central nervous system. we also demonstrated that glycopeptides able to reveal high antibody titers in multiple sclerosis sera are characterized by a type i we describe here the result of a conformationally driven rational design exercise, which led to the preparation of new, optimized glycopeptides endowed with enhanced antigenic properties. most importantly, the same approach, based on structure alignment, was used to shed light on the native antigen(s), target of pathogenetic autoantibodies involved in demyelination processes vitro and in vivo evaluation for cholecystokinin-b receptor imaging istituto nazionale per lo studio e la cura dei tumori ome (f0)
(aib, α-aminoisobutyric acid) to investigate its binding properties to tb(iii) ions. according to our published spectroscopic results f0 populate a set of ordered conformations involving 310/α-helical segments and compact structures generated by the formation of a turn around the flexible gly5-gly6 central motif. cd experiments showed that the binding of tb(iii) to f0 gives rise to a structural transition of the peptide chain from a helical to a folded conformation. peptide binding is also responsible for the dramatic increase in the tb(iii) fluorescence intensity, suggesting that the tb(iii)/f0 complex may represent an interesting system for imaging applications or bioanalytical sensing the 16 kda protein of mycobacterium tuberculosis provokes specific immune response, therefore related epitope peptides and peptide-conjugates can be considered as potential diagnostics. in our previous study we have determined the functional human t-cell epitope within the 91-110 region. based on this we synthesised two groups of peptides: a) nand c-terminal alanine and beta-alanine elongated variants of the 91-104 epitope and b) 91-104 peptides with alanine substitution at different position according to the hla dr and tcr binding sites. peptides were prepared by solid phase synthesis using boc/bzl or fmoc/tbu strategy. the homogeneity and the primary structure of peptides were checked by analytical rp-hplc, amino acid analysis and esi-ms. the t-cell stimulatory activity of the compounds was investigated using in vitro assays (proliferation and ifn-gamma production) on the 91-110 epitope specific human t-cell clones and pbmc (peripherial blood mononuclear cells) from patients and healthy (ppd+, ppd-) subjects. the effective peptides were conjugated to branched polypeptides with polylysine backbone (sak, eak), tetratuftsin derivative (h-[thr-lys-pro-lys-gly]4-nh2) and lysine dendrimer (h-lys-lys(h-lys)-arg-arg-beta-ala-nh2) (map) carrier via thioether bond formation. the subtitution degree of the conjugates was determined by amino acid analysis. pbmc and human t-cell clones were stimulated with the free peptide alone or with peptide-conjugates containing an equimolar amount of peptide or with a mixture of free peptide and carrier italy we demonstrated, for the first time, that an aberrant post-translational modification (ptm, n-glucosylation) is possibly triggering autoantibody response in multiple sclerosis. this was possible because of a "reverse approach", which led to csf114(glc), a structure based designed glycopeptide, as the first multiple sclerosis antigenic probe accurately measuring high affinity autoantibodies (biomarkers of disease activity) in sera of a statistically significant patients' population universal peptide scaffold" to be modified with a series of glycosyl amino acids (different in sugars and linkages), in the aim of developing personalized diagnostic/prognostic tests. the csf114 beta-turn structure, exposing at the best the aberrant ptm specific for antibody-mediated forms of other autoimmune diseases, will lead to a family of antigenic probes to be used in diagnostic this information is encoded by the distribution of the electron-ion potential (eiip) of amino acids along the sequence and is represented by the frequency components in is. proteins with the same biological functions or interacting proteins (e.g. antibody/antigen) share the information corresponding to the common frequency components in their iss. investigation of the hiv-1 envelope glycoprotein gp120, as a model system for hypervariable proteins, revealed that this information is strongly conserved and is not significantly affected by natural mutations. the c-terminus of the second conserved region (c2) of gp120, encompassing ntm peptide is important for infectivity and neutralization of hiv-1, while human natural anti-vasoactive intestinal peptide (vip) antibodies reactive with gp120 play an important role in control of hiv disease progression. ntm/vip multiple copies were coupled to an artificial sequential oligopeptide carrier for developing an immunoassay (elisa) as a reproducible, reliable and sensitive tool for the detection of anti-ntm/vip derived antibodies these peptides have been utilized in an immunopeptidometric assay for specific measurement of active, noncomplexed psa. however, this assay has not been sensitive enough for the measurement of active psa in clinical samples. therefore, we aimed to develop an improved assay utilizing the same principle as previously, but using a more sensitive detection method based on proximity ligation assay. methods: in the assay, psa is first captured on a solid phase by a psa antibody czech republic rapidly increasing knowledge of new gonadotropin-releasing hormones (gnrh)of different species of the animal kingdom induces the need to prepare new synthetic derivatives and fragments of these peptides with higher potency and metabolic stability and suitable for the formulation of new immunogens. the species related differences in the sequence of the native mammalian gnrh pglu-his-trp-ser-tyr-gly-leu-arg-pro-glynh2 concern predominantly the positions 5, 7 and 8, particularly tyr in position 5 is replaced for his or leu, leu in position 7 by val or trp, and arg in position 8 is substituted by lys, ser, asn or gln. several gnrh derivatives with with the above substitution and gnrh fragments were prepared by solid phase peptide synthesis and purified by rp-hplc. purity of the synthetic peptides was checked by capillary zone electrophoresis (cze); peptides were analysed as cations in acidic backround electrolytes (ph 2.25 -2.quantitative analyses for determination of their effective electrophoretic mobilities and the estimation of their effective charges.supported by grant of ministry of agriculture of cr-nazv qf 3028 by rants of ga cr nos we use peptaibiomics for the structural determination of peptaibiotics from fungi grown on single agar plates thus avoiding time-consuming isolation and purification procedures. the method comprises fast and effective solid-phase extraction followed by on-line rp-hplc coupled to tandem esi-ms. here we present a survey of the peptaibiome of hypocrea species. in extracts of hypocrea semiorbis, h. vinosa, h. dichromospora, h. gelatinosa, h. nigricans, h. muroiana and h. lactea a multitude of short and long-chain peptides containing aib could be characterized. the formation of new and known peptaibiotics could be established by comparison with sequences stored in data bases japan process scale rp hplc purification of peptides and proteins is increasingly important in bio-pharmaceutical production. besides selectivity, other crucial factors are loadability, recovery loadability is believed to depend on the surface area of the packing material. consequently, smaller pores providing larger surface area should lead to increased loadability. this principle is misleading in the case of large molecules, because they cannot penetrate smaller pores. therefore the chromatographically accessible surface area has to be taken into account. recovery problems like irreversible adsorption or aggregation are frequently caused by hydrophobic surface properties of ods phases. the less hydrophobic c8 is a substituent to avoid considerably these problems. however c8 is less durable than ods under extreme acidic conditions. our new proprietary c8 modification technology combined with a perfect end-capping minimizes the presence of residual silanol groups and protects the silica surface sp-200-c8-bio demonstrates high mechanical stability by no obvious alteration of back pressure and particle size after 10 repeated packing cycles in dac columns. by overcoming the common weaknesses of the conventional c8 rp silica phases, daisogel sp-200-c8-bio opens new avenues for process scale separation of peptides and proteins. m514 determination of peptide: protein molecular ratio in conjugates by seldi-ms method synthetic peptides are widely used as antigens in various research and practical areas of biology and medicine. peptides with molecular masses < 5000 kda should be conjugated with carrier proteins in order to ensure their immunogenicity and protect from proteolysis. in these cases the comparison of peptide immunogenicities and immunotest system development should be performed having in mind exact peptide-to-protein ratios. 23 conjugates of peptide fragments of hepatitis c virus envelope protein e2 with ovalbumin, bovine serum albumin, and myoglobin were prepared using glutaraldehyde (ga), m-maleimidobenzoyl n-hydroxysuccinimide ester, dimethyl suberimidate (dms), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide as conjugating reagents. the rough evidence of the peptide-protein conjugate formation was obtained by page. the exact peptide:protein molar ratio was estimated in all 23 conjugates by seldi-ms. almost all conjugates had oligomeric structures due to the formation of intermolecular linkages between proteins. the peptide : protein molar ratio in conjugates varied from 1:1 to 13,6:1. conjugates obtained with the ga were more diversified in the number of peptide molecules linked to carrier proteins (peptide:protein ratios ranged from 3:1 to 13:1) than other conjugation reagents mazur-marzec 1 poland posttranslational modifications (ptms) like phosphorylation, acetylation, or methylation have been shown to play a significant role in directing the function of various proteins [1]. in eukaryotes, most of proteins have been shown to be posttranslationally regulated by a variety of different modifications. many effects of ptms include a change of enzymatic activity capillary electrophoresis (ce) has been used to study electrophoretic behavior of ptm-peptides gal-nh2, gal(1-15)-nh2 by capillary electrophoresis. using a phosphate buffer most of ptm-peptides were poorly separated at acidic or neutral ph. the best results were obtained using trifluoroethanol containing separation buffers. optimization of ce separation of maps of peptides containing ptms should allow to detect ptm-proteins and characterize their role in the living cell. comparison of modification events occurring in diseased and healthy cell may iran the purpose of this study was to use the application of multiplex reverse transcription polymerase chain reaction(rt-pcr) assay for detecting the two most common leukemia translocations t(1;19) and t(9;22) in childhood acute lymphoblastic leukemia in iranian children. 32 cases of leukemia patients were screened with the rt-pcr assay. this assay will identify the all type bcr-abl transcripts encoded by the t(9;22) and all described variants of the e2a-pbx1 transcript encoded by the t(1;19). rna was isolated from leukocyte cells of patient's samples. through the construction and optimization of specific primers for each translocation,we have been able to set up multiplex rt-pcr reactions.then pcr products was electrophoresed on agaros gel and were compared with size markers and expected fragtments key words: acute lymphoblastic leukemia -multiplex rt-pcr tu521 study on the syntheses and lc/esi-ms analyses of the glutathione conjugates of bile acids t. wakamiya 1 , m. sogabe 1 a carboxylic acid-containing drug, is metabolized to a glutathione (gsh) conjugate in vivo, and the conjugate is excreted in human urine [1]. although bile acids, compounds with carboxylic acid in molecules, are also expected to form gsh conjugates in liver, no evidence is so far obtained to confirm such metabolism, since there are no suitable standard samples for the research. in the present paper we report the syntheses of the gsh conjugates of main bile acids in human, i.e., cholic acid (ca), chenodeoxycholic acid (cdca), deoxycholic acid (dca), ursodeoxycholic acid (udca) and lithocholic acid (lca) as shown below, and the detailed analyses of these synthetic conjugates by means of linear ion trap lc/esi-ms. furthermore, the evidence for conversion of cholyl adenylate [2] and ca-coa thioester into ca-gsh conjugate will be presented these peptides do no exhibit such strong side effects as csa, but their practical application is hindered because of their poor solubility in water. the 49-57 fragment of tat protein and its analogs, including oligoarginine sequences, are known for their unusual ability to cross cell membranes, skin, and blood-brain barriers. moreover, these peptides are able to transport other substances into cells. this strategy was successfully applied in cases of csa, taxol, and other drugs to improve their bioavailability. now we have synthesized a series of analogues of cyclolinopeptide a, clx, and the immunosuppressive fragment of ubiquitin, covalently bound to the cell-penetrating fragment of tat and its analogues. the ability to cross the biological membranes and the immunosuppressive activities of these conjugates were tested. the conformation of the peptides was determined by circular dichroism methods: we used fluorescein-labelled cationic cell-penetrating peptides and analyzed the uptake efficiency (flow cytometry) as well as the intracellular distribution (confocal laser scanning microscopy). the bioactivity of a proapoptotic cargo-peptide, delivered into the cells either via electroporation or via cpps was quantified using a caspase-3 activity assay and cellular assays. to address the integrity of cpps during their trafficking, a fluorescent double-labelled antp peptide was designed and used as an intracellular fret-sensor. results: endocytosis-mediated uptake of the cpp-cargo conjugate led to a significant reduction of cargo bioactivity compared to its direct transfer via transient membrane permeation. this finding was related to the sequestration of peptides within endocytic vesicles but also, in the case of the tnf response, to the induction of receptor internalization during cell entry. moreover, during endolysosomal passage peptides undergo significant proteolytical degradation. conclusions: the endocytosis-dependent uptake mechanism of cholesterol pullulan (cp), in which maltose moieties are partially modified by cholesterol, is unique in forming self-assembled nanoparticles (20-30 nm) in water. combination of these characteristics is considered to be promising for development of effective non-viral vectors without toxicity. a conjugate of hiv-tat and cp was synthesized and its gene expression efficiency was evaluated. fully protected hiv-tat-(48-57)-cys(snm)-gly-nh-r was obtained by conversion of the corresponding cys(acm) peptide which was synthesized by the solid-phase method [snm: (n-methyl-n-phenylcarbamoyl)-sulfenyl] [1]. the sulfhydryl function was introduced to the hydroxyl groups of cp by acylation with trt-3-mercaptopropionic acid followed by acid treatment. resulting 3-mercaptopropionyl-cp was coupled with cys(snm) peptide to form disulfide bridge and the protecting groups of the peptide were removed to give the cp-tat conjugate. cp-tat and pcmv-luc complex was transfected into cos7 cells and luciferase activity was analyzed after 24 h. cp-tat elicited remarkable cytoplasmic luciferase activity and low toxicity this finding provides a possibility to use gnrh-iii as a targeting moiety for intracellular drug delivery. therefore we have prepared methotrexate and doxorubicine conjugates of gnrh-iii. the drug molecules were attached to the lys side chain in position 8 of gnrh-iii by thioether bond formation through the gflg spacer elongated with cys either at the c-or n-terminus. since we found earlier that the dimer derivative of gnrh-iii was more effective, new dimer derivatives with a combination of antitumour agents were also prepared. branched gnrh-iii derivative (pyrhwshdwk(clac-glfgc(acm))pg-nh2]) was synthesised by spps. the drug molecules were attached to this compound by thioether bond and finally disulfide bridge was formed between two peptide chains. the cytotoxicity of new derivatives was characterised by mtt test th531 oligopeptide antifungals are exceptionally active against multidrug-resistant yeast previous studies have demonstrated that longer sirnas that are processed by dicer can result in more potent knockdown than the corresponding standard 21-mer sirnas. dicer-substrate 25-27-mer sirnas were conjugated with different structural classes of peptides and their cell uptake properties evaluated. peptides were conjugated to the 5' end of the sirna sense or antisense strand via a thioether bond under denaturing conditions to prevent aggregation and precipitation. the ability of conjugates to translocate fluorescently-labeled sirna across the plasma membrane was evaluated by flow cytometry. the results indicate that some peptides can mediate higher efficiency uptake of sirna into cells compared with lipofectamine or cholesterol-conjugated sirna. the peptide-sirna formulation with 27-mer sirna conjugates showed higher knockdown of tnf-alpha mrna and protein levels in activated human monocytes in vitro compared to the conjugated 21-mer sirna species. the products resulting from in vitro digestion of peptide-conjugated rna duplexes with recombinant human dicer were identified using esi-ms and consisted predominantly of the desired 21-mer sirna several peptides containing the sequence arg-gly-asp (rgd) were studied and developed for their nanomolar affinity to the membrane receptor alfa v beta3 and alfa v beta 5 integrins, which are over-expressed by endothelial cells during proliferation and by tumor cells. to improve the pharmacological profile of some camptothecin derivatives (cpts), five conjugates were designed, where the cytotoxic drugs were covalently attached to the rgd peptide analogues for preferential uptake into tumor cells. the peptides to be used have been selected among a series of new pentacyclic peptides bearing at 5-position a trifunctional pseudoamino acid with a carboxy-terminal side-chain. peptide analogues showing the highest affinity to alfa v beta 3 and alfa v beta 5 integrins were coupled with cpts at different positions. the conjugates have been optimized for binding to the receptors, proteolytic stability and an overall improvement in tumor selectivity. the nature of the linkage between rgds and cpts has a major impact on stability and biological activity of the conjugates. the conjugates with amide bond, but not those with ester bond, are sufficiently stable and show in vitro antitumor activity against a498 and a2780 cell lines combination of amaranth protein with other plant proteins (cereals) enables to formulate the composite protein (near to milk or beef protein, but exclusively on vegetal basis). it is shown on graphs. the aim of the projects' proposals is a development and realization of the technology for fractionation of amaranths defatted flour product is a top protein obtained by removing starches and next polysaccharides decomposed on soluble monosaccharide by specific enzymes. there are shown the chromatograph measuring. we can see complete disintegration of starch and the unchanged proteins. the separate solution monosaccharide is usable for others fermentative processes or as a nutrient solution for yeasts there are description methods for isolation amaranth protein -extraction processes, enzymatic removal starch. the product is a isolate protein rich in essential amino acids. the waste monosaccharide solution was used to production yeasts biomass rich in proteins vitamins amaranth protein isolate have high nutritional value and can be used as food ingredients, for functional, probiotic formulation to begin with, we made epitope mapping with the highly sensitive spot array method (2) in order to study antigenic regions of parvovirus b19 vp1 and vp2 capsid proteins. epitope mapping identified highly reactive, immunodominant early epitope on parvovirus surface that centered to kyvtgin residues of vp1. in the subsequent phases we developed the kyvtgin epitope type specific (ets) igg serodiagnostics. a correlation between enhancing igg avidity to b19 capsid and a transient reactivity with the point-of-care kyvtgin peptide was clear. together the two assays enhanced the value of early diagnosis of b19 infections (3) acute phase-specific heptapeptide epitope for parvovirus b19 diagnosis synthetic peptide arrays on membrane supports-principles and applications human parvovirus b19 infection during pregnancy--value of modern molecular and serological diagnostics 1 laboratory of peptide & protein chemistry & biology 2 department of organic chemistry "ugo schiff" and cnr-iccom 3 department of chemistry 4 department of pharmaceutical sciences glc) able to recognize specific autoantibodies in multiple sclerosis (ms) patients' sera has been developed by the laboratory of peptide & protein chemistry and biology [1and bio-plex suspension array system, biorad. the biosensor technology and bio-plex suspension array system will offer advantages such as rapid analysis, and high sensitivity for a high throughput screening. immobilisation will be based on different strategies that are anchoring the synthetic antigen on different solid supports such as polystyrene well plates (elisa) optimisation of the different techniques was performed with anti-csf114(glc) autoantibodies isolated using affinity chromatography from ms patients' sera. the analytical parameters such as specificity, sensitivity, and matrix effect were evaluated. the different technologies have been used for a high throughput screening of ms sera which control specific cell adhesion.2 here we discuss the route for preparation of amphiphilic block copolymers composed of hydrophobic polylactide and hydrophilic polyethylene oxide (peo) blocks, carrying various cell-adhesion oligopeptide sequences at the end of peo block. fully protected peptide fragments were prepared by solid-phase peptide synthesis by using fmoc strategy and chlortrityl resin. the side-chain protected peptides were cleaved from resin by 25% hfip solution in dcm. the copolymers peptide-polytehyleneoxide were prepared by coupling of the activated peptide fragments with α-amino-ω-hydroxy-peo in dmf using pypop as an activation reagent. subsequently, the polylactide block was grafted to the ω-hydroxy end group of the peptide-peo copolymer via a controlled rop polymerisation of lactide 2r)-2-aminocyclopentanecarboxylic acid (acpc) and beta-methylphenylalanine (beta-mephe) were designed and synthesized to obtain more potent and selective mu-opioid receptor ligands with higher stability against proteolytic enzymes. we have prepared the peptides by spps methods using racemic amino acids. the diastereomeric peptides were separated by hplc. the configuration of the unnatural amino acids in the peptides was determined by chiral tlc using enantiomeric standards. radioligand binding assays and in vitro gpi and mvd assays indicated that several analogues showed high, subnanomol affinity and high selectivity for mu-opioid receptors having agonist or antagonist properties. the incorporation of alicyclic amino acids into the endomorphins resulted in enzyme resistant peptides. the most promishing analogues (dmt-pro-phe-phe-nh2 and tyr-(1s,2r)acpc-phe-phe-nh2) were labeled with tritium using precursor peptides containing dehydroproline or dehydro-(1s,2r)acpc amino acids and tritium gas and pd/baso4 catalyst. the novel peptides and their radiolabelled analogues with high specific radioactivity (1.4-2.8 tbq/mmmol) have become useful pharmacological and biochemical tools for the opioid research iran background and aims: injectable drug delivery based on polymer solution platforms has gained in resent years, particulary for protein-based therapies. the influence of polymer molecular weight (rg 502h, rg504h) on the morphology, erosion of matrices and also on their in-vitro drug release behavior over a period of 28 days was assessed for leuprolide acetate in this study. methods: each formulation was composed of 33% (w/w) polymer and 3% (w/w) leuprolide acetate dissolved in nmp. release studies were performed in a home-made diffusion cell at 37°c. the polymer erosion was studied using two different methods as follows. (a): l-lactic acid detection (b): ph change study. the morphology of the matrices was then analyzed by scanning electron microscope as is shown, the lower molecular weight polymer formulation shows higher porosity and pore diameter due to a rapid phase inversion phase i) can be divided into three more phases with different release rates. results showed that burst effect for rg 502h, 32%, was significantly (p<0.05) higher than rg 504h (13%) italy fabrication of photocurrent-generating systems based on bioinspired organic-inorganic hybrid materials is currently of great interest. more specifically, the photoelectronic properties of nanometric films formed by peptide self-assembled monolayers have been actively investigated. in this work interdigitated gold microelectrodes were modified by covalently linking a hexapeptide ester functionalized by a lipoic acid (lipo) at the n-terminus. the peptide chain [lipo-(aib)4-trp-aib-otbu] comprises five α-aminoisobutyric acid (aib) residues and one trp, a fluorescent amino acid with strong absorptions in the uv region. due to the very high percentage of conformationally constrained aib residues in the chain, the peptide adopts a rigid 3-10-helical structure. cyclic voltammetry measurements indicate that the peptide forms a homogeneously and densely packed monolayer on the gold surface, while current/voltage curves exhibit interesting rectifying properties of the peptide sam. photocurrent generation experiments, performed on the peptide-layered microelectrode, show peculiar modifications of the spectrum. at 240 nm a notably higher photocurrent/voltage response was observed for the peptide-modified electrode, suggesting that a photoinduced electron transfer process from trp to gold does take place with high efficiency this may lead to randomly orientated enzymes and subsequently limited activity. the aim of this work is to selectively activate enzymes at their c-terminal position in order to allow specific immobilisation. we chose akr1a1, an enzyme of the aldo/keto reductase superfamily, for the synthesis of an artificially monolabeled redoxprotein. akr1a1 is a monomeric enzyme and catalyzes the nadph dependent reduction of aliphatic/aromatic ketones and aldehydes. to produce monofunctionalized enzymes we applied the strategy of expressed protein ligation (epl). accordingly, we used the impact®-system and cloned the aldo/keto-reductase as fusion protein with an additional intein/chitin binding domain. through intein mediated splicing we could produce c-terminal thioester of the akr1a1. in the next step, the thioester was coupled to a biotin containing peptide by native chemical ligation. this specifically modified enzyme was immobilised on avidin coated surfaces. the attachment on the surface was tested by tryptic digestion, followed by maldi-tof-ms analysis since safe organic solvent waste disposal is an important environmental problem, we aimed to perform peptide synthesis in water. we have reported solid phase peptide synthesis in water using water-soluble n-protected amino acids, such as 2-[phenyl(methyl)sulfonio]ethoxycarbonyl and 2-(4-sulfophenylsulfonyl)-ethoxycarbonyl amino acids. following to study on water-soluble n-protected amino acids, we developed a new technology based on nanochemistry for solid phase peptide synthesis in water. the new technology is based on coupling reaction of suspended nanoparticle reactants in water. fmoc-amino acids are used widely in peptide synthesis, but most of them show poor water-solubility. we prepared well-dispersible fmoc-amino acid nanoparticles in water by pulverization using a planetary ball mill in the presence of poly(ethylene glycol) (peg). the size of fmoc-amino acid particles was 300-500 nm. to evaluate the utility of this technique, leu-enkephalin was prepared using the nanoparticulate fmoc-amino acids on a peg-grafted rink amide resin in water supramolecular structures formed from n-lipidated oligopeptides immobilized in the regular pattern on the cellulose surface are able to bind ligand molecule, thus acting like artificial receptors. due to the conformational flexibility of lipidated oligopeptide chains, the supramolecular structure is highly flexible, forming the cavities with the shape and prosperities adjusted most effectively to requirements of the guest molecule. structural requirements for a peptide providing the most efficient fit the guest molecules are not known, therefore an array of the artificial receptors have been synthesized and used in the studies. thus, even in the case, when the single receptor in an array does not necessarily have selectivity for a particular analyte, the combined fingerprint response can be extracted as a diagnostic pattern visually, or using chemometric tools in order to improve the sensitivity of the competitive binding and to study the mechanism of molecular recognition, experiments involving fluoresceine and fluoresceine marked acp fragment were performed. we found that λmax and intensivity of fluorescence depends on the structure of the peptide motif and lipidic fragment of receptor this mts was linked with dhhp-6 by disulfide bond, and the new molecular was named mts~dhhp-6. the peroxidase activity of mts~dhhp-6 (2.1x103 u•µmol-1) was tested and similar to that of mp-11 (4.2x103 u•µmol-1). mts~dhhp-6 coated with quantum dots (qds) [3] were observed to accumulate into neonatal rat cardiomyocytes (nrcms) of wistar rats and co-localized with mitotracker red in mt. these results suggest that mts~dhhp-6 is an excellent apx mimics and may have potential proceedings of the twenty-eighth european peptide symposium, kenes international, israel, 2005, 551. references: 1 elastin-based polypeptide, poly(val-pro-gly-val-gly), undergoes self-assembly called coacervation, in which microcoacervate droplets with approximately 1000 nm diameters are formed [1]. nanoparticles cross-linked by cobalt-60 γ-irradiation of these microcoacervate droplets are useful as drug release devices. to investigate the size optimization of nanoparticles, the stability of nanoparticles in the treatment of enzyme, and the drug release profiles from nanoparticles, the three copolymers; poly[10(val-pro-gly-val-gly), (val-ala-pro-gly-val-gly)], poly[4(val-pro-gly-val-gly) application of polyelectrolytes and theoretical models the synthetic heptapeptide rnwdvyk is a fragment of a high affinity receptor (fcεri) for immunoglobulin e (fragment 111-117). it is the active domain for binding with ige. the program of studies of biological properties of the heptapeptide included the investigation of its binding to ige contained in standard solutions and in patients' blood serum. the binding of rnwdvyk with ige was investigated by the ifa method using the ige antibodies labelled with horse-radish peroxidase (hrpo). we determined the optimum sorption concentration of the peptide in this experimental immunoenzyme system to be 100 mkg/ml. the ability of synthetic rnwdvyk peptides to bind with ige was studied as a function of ige concentration in standard serum (0.47 to 60 ng/ml ige). a high correlation was found between the ige concentration and the optical density of the solution after introducing monoclonal antibodies labeled with hrpo and the substrate chromogenic mixture (r=0.99). similar investigations were conducted using the allergy patients' blood serum. the serum with a known concentration of ige was added to immunological plotting boards with sorbed synthetic rnwdvyk peptides. a high correlation was also found between the concentration of ige in the patients' blood serum and the optical density of the solution after introducing monoclonal antibodies labelled with hrpo and substrate chromogenic mixture (r=0.94). our experiments showed the high ige binding activity of synthetic rnwdvyk peptides. we demonstrated the possibility of construction of diagnostic systems for the quantitative determination of ige and ige-antibodies. the fusion protein nucleocapsid-dutpase is present in virions of mason-pfizer monkey betaretrovirus and in virus-infected cells where it potentially contributes to rna/dna folding and reverse transcription (barabas, et al., 2003; bergman et al., 1994; berkowitz, et al., 1995) . in addition to trimeric dutpase core, the protein possesses flexible n-and c-termini consisting of the nucleocapsid segment, and a peptide motif conserved in dutpases. to analyze the function of the flexible cterminal peptide segment, reconstitution experiments were designed with truncated enzyme lacking the c-terminal 14mer oligopeptide and the synthetic oligopeptide prepared on rink-amid resin by solid-phase peptide synthesis, using fmoc strategy. the truncated enzyme proved to be practically inactive. addition of the synthetic 14mer (pyrgqgsfgssdiy) at 100fold molar excess resulted in partial complamentation of the catalytic activity (to 10% of original). a mixture of the truncated enzyme and the 14mer oligopeptide (this latter at 100fold excess) was put to crystallization trials. we conclude that the c-terminal 14mer is essential for catalytic activity. antifolate drugs are inhibitors directed to interfere with folate metabolic pathway. methotrexate (mtx) and pemetrexed (alimta®) are known folic acid analogues used in cancer treatment. different peptide conjugates of mtx have been prepared for intracellular delivery. (1) in octaarginine conjugates one of the carboxylic groups of mtx was attached to the n-terminal of the peptides. (2) however, as results showed, that both carboxylic groups are required to the biological effect of mtx. therefore we decided to synthesize peptide conjugates of folic acid analogues in which the carboxylic groups are untouched. octaarginine, penetratin and a cyclic peptide cgnkrtrgc, which can deliver a cargo molecule in the lymphoid system, were used as delivery peptides. we introduced squaric acid or aminoxy acetic acid as linker moiety between the peptides and cargo molecules. the conjugation was monitored by rp-hplc, the crude products were purified by rp-hplc and were identified by mass spectrometry. the biological activity of the conjugates was evaluated in vitro on sensitive and resistant human leukemia (hl-60) cell lines. besides its endocrine activity, trh (the tripeptide pglu-his-pro-nh2) has also been long recognized as a modulatory neuropeptide with broad range of physiological and pharmacological activities in the central nervous system (cns). although numerous centrally active and metabolically stable analogues and peptidomimetics have been synthesized using trh as a template, selectivity of their cns action has remained an issue to be addressed. we aimed at discovering novel analogues with enhanced cns-selectivity by incorporating pyridinium building blocks. the design also allowed for enhancing transport across the blood-brain-barrier and increasing residence time in the cns through prodrug strategy. solid-phase chemistry was used to prepare the analogues and novel methods previously not used to incorporate pyridinium moieties into resin-bound peptides such as the zincke reaction were also introduced. comprehensive evaluation included measurement of affinity to trh-receptor, acetylcholine-releasing, analeptic and antidepressant-like activity in animal models, as well as prediction of membrane affinity, determination of in vitro metabolic stability, and pharmacokinetics and brain uptake/retention studies that employed in vivo microdialysis sampling. a strong connection between acetylcholine-releasing potency and analeptic effect in animals was obtained for close analogues of trh, while pyridinium compounds designed from the structurally related pglu-glu-pro-nh2 maintained the antidepressant-like effect of the parent peptide, while showing significant decrease in analeptic action.in conclusion, an increase in the selectivity of cns-activity profile was obtained by the incorporation of pyridinium moieties. we have also demonstrated the benefits of the prodrug approach on the pharmacokinetics, brain uptake and retention of the analogues upon systemic administration. the use of small radiolabelled compounds such as peptides is a very attractive tool for the diagnosis of several different pathologies, specially cancer, through the use of nuclear medicine techniques.1 among the various membrane receptors, the two cholecystokinin receptors ccka-r and cckb-r are very promising biological targets for radiolabelled compounds due to their overexpression in many tumours2. in order to develop radiolabelled peptide derivatives able to target these receptors, the binding mode of the c-terminal cholecystokinin octapeptide (cck8), toward the two cholecystokinin receptors ccka-r and cckb-r has been, recently, structurally characterized. 3 the structural data suggest that modifications on the n-terminal end of cck8 obtained by introducing chelating agents and their metal complexes should not affect the interaction of the derivatized cck8 peptides with both ccka-r and cckb-r. here we report the labelling procedures and the in vitro and in vivo characterization of new 99mtc cck8 derivatives. a stable 99mtc-nitrido complex is obtained by using the coordinative set formed by: 1) the n-terminal amino group and the sh cystein of the cck8 derivative cys-gly-cck8 peptide; and 2) a pnp aminodiphosphine used as coligand. several phosphines are used in order to define the best labelling procedures and to optimize the in vivo biodistribution properties of the 99mtc labelled peptides.references various combinations of pore size and chemistry of silica-based materials were investigated for high performance liquid chromatography (hplc) of peptide separation. incorrect pore size and ligands have been suggested to cause peak broadening, poor resolution and poor recovery. our study suggests that an appropriate combination of pore sizes and ligands is necessary to obtain the most efficient usage of reversed-phase hplc columns according to the molecular weights of peptides and proteins. we will also show the possibilities of an improved method development for the separation of complex peptide mixture by ph or additives.the development of new biopolymer materials as drug delivery systems is of enormous interest on biomedicine. dendrimers are polymers with particular properties; they are highly branched polymers with well-defined chemical composition, and show compact globular shape, monodisperse size and controllable surface functionalities. peptide dendrimers incorporates amino acids in their structures and have additional features such as biocompatibility and biodegradability.in previous studies we described the solid-phase synthesis of a new class of polyproline-based dendrimers. these biopolymers have the capacity to cross the mammalian cell membrane and moderate toxicity. these promising results open up the possibility to explore these dendrimers as delivery systems.to design more versatile polyproline dendrimers, we have developed a methodology that involves the combination of solid-phase and solution strategies. diverse multivalent peg-and proline-based cores were synthesized to attain dendrimers with distinct topologies. dendrimers were synthesized by iterative building block addition [(glypro5)2imdoh], around an inner core, using a peptide solution convergent approach. a variety of coupling methodologies and protecting groups for the n-terminal function were explored. the novel high throughput protein detection system using designed peptide arrays has been successfully indicated on their capabilities as the "protein-chip" [1] [2] [3] [4] . our concept has many advantages especially for high-quality industrial production and practical applications compared to arrays with antibodies or recombinant proteins. the deposited peptide solution can be dried without covalent immobilization, although, when the resulted arrays are exposed in protein-solution they showed planned conformation [5] . based on these basic results, several hundreds of α-helical, β-loop and β-sheet peptides, which involved a cysteinyl residue for covalent immobilization and tamra as a fluorescent label, were successfully synthesized, characterized and used as capture molecules. a novel material for chips made from amorphous carbon suitable for our concept has been developed, which has significant advantages over conventional glass or polymer plates, such as no selffluorescence, mechanically more stable, easy manufacturing in the aspects of precised and high throughput processing. thus, chip-plate with nano-l wells could also be easily manufactured. peptides were deposited on these chips surface covalently as well as non-covalently in 350 picol/spot (diameter: ca 200 µm). the resulted chips were used for protein detection. a part of this work was funded by the okinawa-bio-project and nedo-grant. key: cord-023225-5quigar4 authors: nan title: posters date: 2012-08-21 journal: j pept sci doi: 10.1002/psc.2449 sha: doc_id: 23225 cord_uid: 5quigar4 no abstract is available for this article. laboratory of molecular biology and immunology, department of pharmacy, university of patras, patras, greece antimicrobial peptides (amps) are an important component of innate immune system of most living organisms. they have recently gained much attention as new anti-infective drugs with new modes of actions and few or no side effects. their antimicrobial spectrum covers gram-positive and -negative bacteria as well as fungi and certain viruses 1 . fish have proven to be a rich source of antimicrobial peptides. three chrysophsin peptides (chrysophsin-1, -2, -3) have been identified in the gills of the red sea bream, chrysophrys major, which are all bactericidal to pathogenic bacteria at low concentrations 2 . they are cationic α-helical peptides, rich in histidine residues and all end in an unusual rrrh motif. however, in addition to its high antimicrobial potency, chrysophsins have considerable hemolytic activity. the development of new analogues which would preserve high antimicrobial potency, but would lack the undesired hemolytic activity, could be a useful tool with possible commercial and clinical applications. in the present study, we synthesized a series of analogues of chrysophsin-1 with different ratios of lys and leu residues, utilizing the fmoc/but solid phase methodology 3 . the synthesized analogues were purified and isolated by rp-hplc. the antimicrobial properties of the above peptide analogues are currently testing in 3 gram positive (s. aureus, s. epidermidis, e. faecium) and 2 gram negative (e. coli, p. aeruginosa) bacteria. the goal is to identify the minimum bacteriostatic and bactericidal concentrations of the analogues, under conditions that simulate the best possible that of the human organism. hemolytic or cytotoxic activity of the peptides will also be determined. 1 the rise of antibiotic resistance demands the development of new antimicrobial agents. these should exhibit a novel mechanism of action so as to overcome the resistance and be invulnerable to 'not yet acquired resistance mechanisms'. such criteria are difficult to meet. however, cationic host defence peptides (hdps) have emerged as promising candidates. hdps target and disrupt bacterial membranes. in order to evade such a threat a bacterium would need to make substantial changes to its membrane composition disfavouring the development of resistance (1) . however, exact role and mechanism of hpds in the regulation and monitoring of microbial invasions remain to be established. herein we will present new potential mechanisms of antimicrobial regulation by helical hdps using de novo (2) and native systems (3) . biophysical and microbiology aspects of the experimental designs will be discussed. the low number of the newly discovered antibiotics, emergence of multiple-drug resistance, and the alarming death rate due to the infection disease led to development the alternative means to combat the infections. the researchers accumulate information about antimicrobial drugs that could be result of the innate immunity mechanisms. armed only with the innate immunity, the insect has developed into the most widespread class in living kingdom. they produce several antimicrobial peptides with complementary and rapid mode of action. so far there are hundreds of antimicrobial peptides isolated from insect and lot of them are waiting to be discovered. the fleshly neobellieria bullata was chosen for isolation of these active compounds. its larvae in the third instar were squeezed to collect the haemolymph, which was gradually centrifuged and precipitated by acidified methanol. supernatant was subsequently separated by chromatographic methods (spe column, rp-hplc) to obtain fractions of short peptides. identification and characterization of these fractions were performed by tricine electrophoresis, mass spectrometry maldi-tof analysis and n-terminal sequencing. several fractions showed antimicrobial activity against institute of chemical kinetics and combustion, 630090 novosibirsk, russian federation in this work, we extracted 3d-structural information on newly synthesized, medium-length, double spin-labeled peptaibiotics using peldor spectroscopy. we investigated the magnetic dipole-dipole interactions between spin labels and the orientation selectivity effects. in particular, the medium-length peptaibiotics tylopeptin b 1,2 and heptaibin 3 , double spin-labeled with the nitroxyl probe toac (4-amino-1-oxyl-2,2,6,6-tetramethylpiperidine-4-carboxylic acid), were studied by means of x-band peldor spectroscopy. this study was conducted on tylopeptin labeled at positions 3 and 13 (t313) and heptaibin labeled at positions 2 and 14 (h214) in frozen glassy methanol solutions at 77 κ. peldor data analysis was carried out using the theory developed for short interspin distances. the distance distribution functions between spin labels for τ313 (maximum at 1.78 nm, halfwidth of 0.08 nm) and η214 (maximum at 2.30 nm, half-width of 0.05 nm) were determined. the intramolecular distances observed between the labels allowed us to assign an essentially α-helical conformation to τ313 and a largely prevailing 310-helical structure to η214 under the aforementioned experimental conditions. are amidated at the c-terminus, as a result of a posttranslational enzymatic reaction. temporins are particularly active against gram-positive bacteria and are not toxic to eukaryotic cells. in this study we designed a series of analogues of tb with the aim to improve the peptide antimicrobial activity against both gram negative and gram positive strains and then to structurally elucidate the mechanism of interaction of active peptides with lps. the peptides have been synthesized substituting one or two amino acids with an alanine and lengthening the sequence with positively charged amino acids. among the 16 designed peptides, one of the analogues, tb_kkg6a, showed highly increased activity against gram negative bacteria and also a slightly increased activity against gram positive bacteria with a total lack of hemolytic activity. to develop ll-37-derived short amps with prokaryotic selectivity and lipolysaccharide (lps)neutralizing activity, a series of amino acid-substituted analogs based on ig-19 (residues 13-31 of ll-37) were synthesized. analog a4 showed the highest prokaryotic selectivity, but much lower lps-neutralizing activity compared to ll-37. the analogs, a5, a6, a7 and a8 with higher hydrophobicity displayed lps-neutralizing activity comparable to that of ll-37, but much lesser prokaryotic selectivity. these results indicated that the proper hydrophobicity of the peptides is crucial to exert the amalgamated property of lps-neutralizing activity and prokaryotic selectivity. to increase lps-neutralizing activity of the analog a4, we synthesized trp-substituted analogs (a4-w1 and a4-w2), in which phe 5 or phe 15 of a4 is replaced by trp. despite their same prokaryotic selectivity, a4-w2 displayed much higher lps-neutralizing activity compared to a4-w1. this result suggested that the effective site for trp-substitution when designing novel amps with higher lps-neutralizing activity, without a remarkable reduction in prokaryotic selectivity, is the amphipathic interface between the end of the hydrophilic side and the start of the hydrophobic side rather than the central position of the hydrophobic side in their α-helical wheel projection. furthermore, d-enantiomeric peptides (a4-w1-e and a4-w2-e) of a4-w1 and a4-w2 possessed not only more improved prokaryotic selectivity and retained lpsneutralizing activity compared to a4-w2 but also protease stability. taken together, a4-w1-e and a4-w2-e can serve as promising templates for the development of therapeutic agents for the treatment of endotoxic shock and bacterial infection. department of zoology, faculty of science, charles university, prague, czech republic antimicrobial peptides (amps) are among the most promising lead compounds for developing medicines in the fight against resistant pathogenic bacteria. we have already shown that the venom of wild bee is a rich source of pharmacologically interesting antimicrobial peptides [1] [2] [3] [4] . from the venom of solitary bee macropis fulvipes, we isolated and characterized the novel antimicrobial peptide named macropin (mac-1). by edman degradation and mass spectrometry, its primary sequence was established as gfgmalkllkkvl-nh2. mac-1 possesses potent antimicrobial activity against both gram-positive andnegative bacteria and moderate hemolytic activity against human red blood cells. cd spectra confirmed that mac-1 can form an amphipathic α-helical secondary structure in the presence of membrane-mimicking substances as sodium dodecyl sulfate or organic solvents like trifluoroethanol. we prepared a series of mac-1 analogs to study the effect of incorporating d-amino acid residues into the sequence in various positions on antimicrobial and hemolytic activity, α-helicity and serum stability. the substitution of l-amino acid residues at n-terminal part of sequence by d-amino acid residues led to the improving hemolytic activity with maintaining or increasing antimicrobial activity. these modifications increased peptide stability in human serum. effect of the incorporation of d-amino acid residues into the mac-1 sequence on its α-helical structure will be discussed. the neutralization of endotoxins (lipopolysaccharide, lps) by suitable compounds has been shown to be a key step in the treatment of infectious diseases, in particular in the case of gram-negative bacteria. the active endotoxic center of lps is lipid a, its lipophilic part. an effective antimicrobial peptide against gram-negative bacteria is magainin 2, which was originally found in the skin of an african frog. here, we studied the interaction of hexa-acyl bisphosphoryl lipid a 1 prepared from erwinia carotovora lps with magainin 2 with some minor substitutions in the amino acid pattern. by using fourier-transform infrared spectroscopy, the gel to liquid crystalline phase transition of the acyl chains of lipid a, the conformation of their phosphate groups due to peptide binding, and the profile of the secondary structure of the peptides was investigated. the zeta potential of lipid a aggregates in the presence of the peptides was determined by measuring the electrophoretic mobility. small-angle x-ray scattering was performed for the elucidation of the aggregate structures in the absence and presence of the peptides, and isothermal titration calorimetry was applied for evaluating the thermodynamics of binding between peptides and lipid a. the data show that asp-or glusubstituted peptides improved the binding activity to lipid a correlated with characteristic changes in the physical parameters, which were stronger expressed for the aspsubstituted peptide. the new hydrogen bond connection between glu and asp by carboxylic acids apparently leads to a more pronounced -structure of the peptide. the conformation change of the peptide enhanced the activity of incorporation into the lipid a aggregates, along with changes in biochemical and biophysical parameters. royal college of surgeons, dublin, ireland cationic antimicrobial peptides (caps) have been reported to exhibit anticancer activity 1 . one such peptide, p18, has been shown to inhibit the growth of several cancer cell lines, with inhibiting concentration (ic50) in the range of 10 to 20 μm 2 . however the concentration at which p18 and other caps act is too high to be clinically relevant. the enhancement of their activity can be achieved through the modification of their amino acid composition or the addition of other molecules. conjugation of naturally produced hydroxylated fatty acids to p18 showed a 10-fold improvement in its anticancer activity on a variety of human-derived cell lines. in addition to the enhancement of activity we wished to understand the mechanism of action of the peptide and conjugates. we investigated the uptake of conjugated and unconjugated peptides into hela (cervical) and miapaca (pancreatic) human cancer cells and the localisation of the peptide in the cell once taken up. we investigated the effect of altering the carbon number of the hydroxylated fatty acids ranging from hydroxyhexanoic acid (r6) to hydroxydodecanoic acid (r12) conjugated to p18 peptide and tested on hela and miapaca cell lines. circular dichroism studies were performed to investigate the effect on α-helical content due to amino acid composition alteration and hydroxyalkanoic acid conjugation. the effect of the position of the hydroxyl moiety on enhancement of activity was also investigated. in the current study p18 and its derivatives also lacked haemolytic activity with concentrations up to 66 fold higher than ic50 values needed to observe any haemolysis. when current antibiotics become less efficient, there is a promise that some antibiotics can be replaced by other nature's substances, e.g. peptides. halictines are novel antimicrobial peptides isolated from the venom of the eusocial bee halictus sexcinctus. we obtained four analogues of the native peptide hal 1 from iocb av cr. they already characterized structural properties of these peptides and their antimicrobial activity against selected bacteria 1 . the analogues were prepared by point mutations of native peptide, which could increase antimicrobial activity and decrease undesirable hemolytic activity. our aim was to characterized membrane permeation activity of halictines through the use of a basic model of biological cells -large unilamellar phospholipid vesicles luvs. we prepared two basic types of leakage assays based on luvs with free dyes entrapped inside and one assay with laurdan content. we used classical steady state fluorescence spectroscopy 2 and advanced fluorescence methods 3 for study of dyes escape from luvs and we also used laurdan generalized polarization technique gp 4 for better understanding peptide insertion into membrane. in this way we received complementary information and we can conclude that the most active peptides are the native hal 1 and analogue hal 1/6. however hal 1/6 requires presence of negatively charged phospholipids in membrane which may explain its higher selectivity against bacteria. furthermore, fcs results have shown that the leakage happens via pore formation. results from gp revealed that peptide insertion in the membrane do not lead directly to formation of pores. against a wide range of microorganisms, mainly by perturbing the permeability of bacterial membranes through the formation of pores. however, amps effects on membrane properties probably extend beyond poreformation. we performed a systematic spectroscopic analysis of the effects on membrane structure and dynamics of two very different amps: the cationic pmap-23, which creates pores according to the "carpet" model 1 , and alamethicin, which forms "barrel-stave" channels 2 . by using fluorescence anisotropy measurements on liposomes comprising probes localized at different depths in the bilayer, we measured peptide effects on membrane fluidity and order. laurdan spectral shifts provided indications about water penetration in the bilayer. in the case of pmap-23, it was possible to focus specifically on the lipids surrounding the peptide by following the membrane-probe fluorescence due to fret from the peptide trp residues. finally, peptide-induced perturbation of lateral mobility and domain formation were determined by several methods. all experiments were compared with liposome-leakage measurements: while for pmap-23 all membrane-perturbing effects are correlated with the vesicle leakage process, alamethicin does not significantly influence membrane dynamics at the concentrations in which it forms pores. surprisingly, in all cases the most significant peptide-induced effect is a reduction in membrane fluidity. we have reinvestigated 20-residue peptaibols named metanicins from an ascomycetous fungus originally described as metarhizium anisopliae strain cbs 597.80 (cbs = centraalbureau voor schimmelcultures, utrecht, the netherlands). however, due to unusually shaped conidia and based on rna-sequencing of its internal transcribed spacer (its) region, the identification of cbs 597.80 as metarhizium has been withdrawn and this particular strain is currently under taxonomic reinvestigation 2 . sequencing of four isolated peptides by fab-ms, esi-ms and edman degradation of partial hydrolysates revealed structural relationship to 20-residue peptaibol antibiotics paracelsins from trichoderma reesei (=hypocrea jecorina). sequences determined are: ac-u-a-u-a-u-a(u)-q-u-v-u-g-l-u-p-v-u-u(j)-q-q-fol (exchange positions in parenthesis; ac, acetyl; u, aib, α-aminoisobutyric acid; j, d-isovaline; fol, l-upmc univ paris 06 laboratoire des biomolécules; cnrs umr 7203; ens lbm; address: laboratoire des biomolécules, ens dpt de chimie, 24, rue lhomond f-75005, paris, france current data suggest that the cellular uptake of cellpenetrating peptides (cpps) occur by two processes: direct translocation across the plasma membrane and endocytosis 1 . the large diversity of cpp sequences described in the literature (derived either from fragments of proteins, structurally constrained synthetic peptides, peptide libraries 2 or dendrimers) has hampered the identification of general rules for their efficacy of internalisation. we have used a reductionist approach, restricting the cpp functional groups (amide and guanidinium) and tailoring cpp amphiphilic properties. two families of cpps have been designed: 1) primary amphiphilic cpps corresponding to tetra-arginines functionalised with fatty acid chains of different lengths and 2) secondary amphiphilic cpps containing arginine and alanine or tryptophan residues 3 . these cpps were linked by a disulfide bridge to a peptide inhibitor of protein kinase c (pkci). the efficiencies of internalisation of the conjugates were quantified by a method based on maldi-tof mass spectrometry previously developed in our group 4 . the mechanism of internalisation was studied by comparing the amounts of cell-surface bound and internalized pkci cargo on cho-k1 cells and glycosaminoglycan-deficient cho cells at 4 o c and 37 o c. conjugates were found to enter by both direct translocation and glycosaminoglycandependent endocytosis. in addition, the primary amphipathic cpps were found to be more efficient than the secondary amphipathic ones. furthermore, structural or mechanistic novelty does not guarantee immunity from resistance, with strains resistant to linezolid identified prior to fda approval. therefore, modifying existing antibiotics to overcome resistance mechanisms presents an opportunity to rationally develop effective new drugs more rapidly than screening for new structures. vancomycin is a glycopeptide commonly used as a front line treatment for infections caused by methicillinresistant staphylococcus aureus (mrsa). the emergence of vancomycin-resistant enterococci (vre), vancomycinintermediate s. aureus (visa) and vancomycin-resistant s. aureus (vrsa) has prompted the development of semisynthetic glycopeptides 3 . we have generated a variety of glycopeptide derivatives that show superior antibacterial activity against mrsa and vre compared to vancomycin and second generation lipoglycopeptides. this was undertaken by employing a combination of solid phase and solution phase chemistry to attach a membraneassociative element that selectively binds to bacterial membranes in preference to eukaryotic membranes, thus increasing the local concentration at the lipid ii d-ala-d-ala peptidoglycan cell wall precursor target site. three novel antimicrobial peptides, named panurgines (png), were isolated from the venom of wild bee panurgus calcaratus. one of them is dodecapeptide with sequence lnwgailkhiik-nh2 (png-1). the next two peptides are almost identical. these are cyclic peptides containing 25 amino acid residues and two intramolecular disulfide bridges ldvkkiicvackixpnpackkicpk-oh (x=k png-k and x=r png-r). all peptides exhibited antimicrobial activity against gram-positive bacteria and gram-negative bacteria, antifungal activity and low haemolytic activity against human erythrocytes. we prepared 11 analogues of α-helical amphipathic png-1 with the aim to improve its biological properties and a linear analogue of png-r to elucidate the importance of disulfide bridges for its activity. in the second part of the study, we followed the effect of panurgines on the degree of membrane disruption by observing the leakage of fluorescence dye (calcein) entrapped in artificial phospholipids vesicles [1] . specifically, we investigated membrane interactions of pngs with the vesicles made from negatively charged 1:2 dopc/dppg and 1:2 dopc/dopg vesicles as a general model of bacteria membrane and 15:80:5 dopc/dopg/cl as a possible model for a membrane of bacillus subtilis. the membrane interaction of pngs was also investigated on uncharged dopc vesicles as potential model membrane for erythrocytes. pngs exhibited weak dye-leakage activity for neutral vesicles, while they effectively induced dye leakage in the presence of negatively charged vesicles. these results indicate that pngs have stronger potency to disrupt bacteria-mimicking anionic membranes than those which mimic eukaryotic cell membrane. department of biochemistry and toxicology, university "lucian blaga", 550012 sibiu, romania a common tool to bias the conformation of linear peptides is the insertion of side-chain modified amino acids or sidechain/main-chain conformationally restricted building blocks. an alternative approach is a simple backbone modification. in this connection, backbone amide replacements with (almost) isosteric surrogates were extensively used. these modifications may impart resistance to enzymatic degradation and better bioavailability to the peptides, but also influence the secondary structure. a thioamide (ψ[cs-nh]) is perhaps the closest structural mimic of an amide. however, it possesses different and attractive features: (i) its nh group forms stronger hydrogen bonds, being more acidic than that of the amide. (ii) its c-n bond undergoes cis/trans isomerization by irradiation at 260 nm (π→π* transition). (iii) it may act as a "minimalist" fluorescence quencher. for all these reasons, we started a programme aimed at exploring how the endothioamide bond affects peptide folding and bioactivity. in this communication, we describe the synthesis and conformational results of the three analogs of the membrane-active peptaibiotic trichogin ga iv listed below: n-octanoyl-aib-gly-ψ[cs-nh]-leu-aib-gly-gly-leu-aib-gly-ile-leu-ome (2/3) n-octanoyl-aib-gly-leu-aib-gly-ψ[cs-nh]-gly-leu-aib-gly-ile-leu-ome (5/6) n-octanoyl-aib-gly-leu-aib-gly-gly-leu-aib-gly-ψ[cs-nh]-ile-leu-ome (9/10) the syntheses of the three peptides were accomplished in solution according to a fragment condensation approach. appropriate thioamide-containing tri-or tetrapeptides were prepared by treating the corresponding all-amide precursors with the lawesson reagent. ft-ir absorption, 2d-nmr and cd conformational investigations on the three analogs were conducted in comparison with the naturally occurring peptaibiotic. all three analogs maintain the capability to interact with the dope/dopg model phospholipid membranes and exhibit a comparable bioactivity against s. aureus. peptide-peptide interaction of lactococcin g class iib two peptide bacteriocin h. etayash, w.soliman and k. kaur* faculty of pharmacy and pharmaceutical sciences, university of alberta, edmonton, alberta, t6g 2e1 lactococcin g, a class iib two-peptide bacteriocin, consists of two complementary peptides lcng-α and lcng-β that act as one functional unit with optimal antimicrobial activity achieved by the presence of both peptides in approximately equal amounts. in this study we have investigated the mechanism of pairing of the two complementary peptides as well as explored any specific interaction that could take place between the peptides. molecular dynamics (md) simulation was employed to study the interactions at the atomistic level. four different md simulations with the peptides in a lipid bilayer system were conducted. md results from these simulations confirmed and pointed out that (i) the two putative gxxxg motif, g7xxxg11 in lcng-α and g18xxxg22 in lcng-β, were attracted and came closer to each other, showing the role of these motifs in attracting the two peptides to each other. closer views, however, showed no clear interactions between these two motifs. most likely, nonspecific interactions play a role in bringing the two peptides together; (ii) variations and loss in the secondary structure in both the peptide fragments were confirmed among the four simulations. on the contrary, stability of helical regions was identified between residues w3-g9 and d26-q29 in lcng-α and v9-e14 in lcng-β; and (iii) role of tryptophan at the n-terminal regions in positioning and setting the peptide orientations were confirmed which matched the previous reported results. faculty of pharmaceutical sciences, unesp -univ. estadual paulista, araraquara, sa͂ o paulo, brazil antibiotic resistant bacterial strains represent a global health problem. antimicrobial peptides (amps) are promising novel antibiotics because they have displayed little or no resistance effects. it is well known that the charge, amphipathicity, hydrophobicity and helicity of the peptide are fundamental for the biological activity. in addition, covalent dimerization appears as a new parameter to be studied. in this way, several bioactive sequences were dimerized obtaining pharmacotechnics advantages like enhanced antimicrobial activity, solubility and proteases resistant. however, the effect of this modification is unclear since dimeric versions of some amps are toxic 1 . to evaluate the effects of dimerization on the structure and biological activity of the amp aurein 1.2, the monomeric version (au) and the c-and n-terminal dimers, (au)2k and e(au)2, respectively, were synthesized. circular dichroism results indicated that dimeric versions showed more defined structures in aqueous solution. e(au)2 showed "coiled coil" structure while (au)2k an αhelix structure. in contrast, au displayed typical spectra for disordered structures. in tfe and lpc, all the peptides acquired a high amount of α-helix structure. the antimicrobial activity against bacteria and yeast decreased with dimerization. however, dimeric peptides promoted the aggregation of c. albicans. hemolytic and vesicle permeabilization assays showed that au has a concentration dependence activity, an effect that can be assigned to a "carpet" like mechanism peptide, whereas this effect was less pronounced for dimeric versions, suggesting that dimerization may change the mechanism of action. in conclusion, our studies showed that the effects of amp dimerization are complex and still unclear. 1 , the first antimicrobial peptide generated in vivo and isolated from the gut contents of the cattle tick boophilus microplus 2 . we have shown that these peptides are equally lethal to candida albicans mdm8 and practically not active on human erythrocytes 1 . to examine the properties and mode of action of hb40-61a, we synthesized it and its fluorescently labeled analogue (fam-hb40-61a) by the solid-phase method at 60 o c, purified them by rp-hplc and characterized their purified forms by lc-esims. at low salt concentration, both peptides were found to inhibit the growth of candida albicans atcc 90028, candida parapsilosis atcc 22019 and candida krusei atcc 6258, but hb40-61a was two-fold more active (mics of 12.5; 12.5 and 50.0 μm, respectively). at those concentrations, both peptides also kill the fungi. assays with human erythrocytes showed that, likewise hb40-61a, fam-hb40-61a present activity lower than 25% at 100 μm. apparently, hb40-61a targets the membrane cell because confocal microscopy analysis revealed that, at the half of mic value, fam-hb40-61 accumulates on the fungal cell membrane. in contrast, fluorescence activated cell sorting (facs) analysis revealed that, at the mic, more than 90% of the fam-hb40-61a penetrates into the cell. membrane permeability assay using hb40-61a, c. albicans atcc 90028 and the kit live/dead funga light confirmed progressive membrane damage associated with an increase in peptide concentrations. the use dibac4 (5) and facs analysis showed that hb40-61a alters the plasma membrane potential, leading to cell death. supported by fapesp, cnpq and capes. lasso peptides form a growing class of 16 to 21 residue ribosomally-synthesized and post-translationally modified peptides produced by bacteria. they share a rigid and compact interlocked structure consisting of a macrolactam ring at the n-terminus and a c-terminal tail that is looped back and threaded through the ring, forming a typical [1] rotaxane 1, 2 . the macrolactam is formed by condensation of an asp8 or glu9 side-chain with the free amino group of a gly1 or cys1. the lasso fold is stabilized either by steric hindrance assumed by bulky amino acid side-chains and/or by disulfide bonds between cysteines from the tail and the ring. given this structure, lasso peptides display a high stability against proteolytic and chemical degradation. they are biologically active on various enzymatic targets, which confer them in some cases an interesting antimicrobial activity. given its characteristics, the lasso scaffold thus represents a promising tool for biotechnological application in the development of bioactive peptides. until now, nine peptides had been structurally characterized as lasso peptides. based on a genomics-based approach, we identified a novel lasso peptide from streptomyces sviceus that we termed sviceucin. it was produced in high yield by heterologous expression in s. coelicolor and submitted to structural analysis by mass spectrometry and nmr. sviceucin is 20residue long and stabilized by two disulphide bonds. their connectivities were identified mainly from the typical noes between the beta-protons of the cysteines. the lasso structure of sviceucin was obtained by nmr-based molecular modelling. sviceucin was shown to exhibit antibacterial activity directed against gram positive bacteria, while gram-negative bacteria and fungi showed resistant. the penicillium chrysogerum antifungal protein (paf) is a cysteine-rich, cationic protein that inhibits the growth of a variety of filamentous fungi without toxic effect on mammalian cells 1 . although paf is used to be produced in p. chrysogerum or a similar microorganism, preparation of analogues of the protein for structural and functional investigations requires an efficient chemical method. the unsuccessful continuous synthesis of the 55-mer small protein prompted us to use native chemical ligation 2 . the syntheses of the fragments were performed by solid-phase method applying tboc chemistry. using the acid-labile tboc protecting group, the thioester end of the n-terminal fragment remains intact during the course of the synthesis. the first attempt was the synthesis of peptides with pmethylbenzyl groups on the side chains of all of the six cysteine residues. under no circumstances oxidative folding provided the natural disulphide bridge pattern. the failed attempts led us to orthogonal protection of the sulphydryl groups. different sets of protecting groups were tried and evaluated. our experiments showed that basic treatment triggered rearrangement of the previously formed disulphide pattern. thus, base-labile protecting groups (such as 9-fluorenylmethyl, fm) have to be avoided in the synthesis of paf. the alarming increase and spread of antibiotic resistance among bacterial pathogens has stimulated the development of new antibacterial agents with innovative mode of action. antimicrobial peptides with broad spectrum activity are widely distributed in nature and play an important role in innate immunity in several species, including humans. tigerinins are a unique family of 11-to 12-residue antimicrobial peptides found in skin secretion of the indian frog rana tigerina 1, 2 . characterized by a disulfide-bridged loop composed of nine amino acids, tigerinins do not show primary structural homology to any known antimicrobial peptides from amphibians. tigerinins could provide novel lead compounds for the design of effective antimicrobial peptides with a new mode of action. the peptide murdp1 has been identified after the screening of phage display libraries against pseudomonas aeruginosa cell wall biosynthesis murd amide ligase enzyme 3 . murdp1 is a low micromolar range inhibitor of murd enzyme and showed good antimicrobial activity. composed of nine amino acids, it is also characterized by a nine residues disulfide-bridged loop containing two prolines. this great similarity with tigerinins, led us to investigate if murd enzyme could be a potential target for these peptides. in silico analyses using modelling, molecular dynamics and docking with p. aeruginosa murd showed that murdp1 and tigerinin-1 and -2 make similar interactions in the binding site. these results suggest that murd may be an intracellular target for tigerinin-1 and tigerinin-2. synthesis, murd enzymatic inhibition assay, antibacterial activity evaluation and structure-activity relationships of murdp1 and tigerinins analogs will be presented. h. etayash, l. norman, t. thundat*, k. kaur* faculty of pharmacy and pharmaceutical sciences, department of chemical and materials engineering, university of alberta, edmonton, alberta t6g 2e1, canada listeria monocytogenes is a gram positive bacterium that accounts for about 28% of the deaths resulting from food borne illnesses in north america. moreover, l. monocytogenes is considered one of the most difficult bacteria to detect in contaminated food products. while standard microbiological and biochemical assays currently used are accurate and sensitive, they are time consuming and often require specialized instruments operated by a trained user making on-site testing difficult. to this end, we propose the development of an antimicrobial peptide (amp) or peptide fragment sensor for the on-site detection of l. monocytogenes. leucocin a, which is a naturally occurring amp consisting of a 37 amino acid sequence, is known to exhibit specific activity against l. monocytogenes at pico to nanomolar concentrations. for this reason, we have synthesized a shorter peptide fragment of leucocin a consisting of 24 amino acids using solid phase peptide synthesis. the peptide was purified by reversed phase hplc and maldi-tof mass spectrometry indicates the desired biological entity was achieved. by including an n-terminal cysteine group, the tailored amp was readily immobilized at a gold interface. the resulting thickness and molecular orientation, determined by ellipsometry and grazing angle infrared spectroscopy, respectively, indicate that the helical peptides were adsorbed on the interface with a preferred orientation parallel to the surface. the bacterial specificity of the anchored leucocin a fragment was tested against three gram positive bacteria and results reveal that the adsorbed amp exhibits a limit of detection of approximately one bacterium/μl which is a clinically useful detection range. faculty of science, university of south bohemia, české budějovice, czech republic during the last few years we have identified three novel defensins from arthropods. two of them, lucifensin 1 and lucifensin ii were purified from various tissues of lucilia sericata and l. cuprina larvae, respectively. larvae of these flies are routinely used in the hospitals around the world for the treatment of non-healing infected wounds in the procedure known as maggot therapy. these 40 amino acid residues and three disulfide bridges peptides differ from each other only in one amino acid residue in position 11 (val-ile). linear precursor of lucifensin was prepared by fmoc-spps chemistry which was then subjected to the oxidative folding yielding a peptide with a pattern of disulfide bridges identical to that of native lucifensin and other insect defensins. this was examined by the identification of the fragments resulting from the thermolysin digestion of lucifensin by means of mass spectrometry. however, this cyclization reaction proceeded via an intermediate having incorrect pairing of disulfide bridges. from the hemolymph of blood sucking tick dermacentor marginatus (d.m.) we purified defensin containing 38 amino acids and three disulfide bridges. its sequence determined by edman degradation and mass spectrometry was identical to that previously determined by molecular biology methods 2 . sequence of d.m.defensin shows no homology to insect defensins. by spps prepared linear precursor of d.m.-defensin was subjected to oxidative folding under the open air. the linear peptide was straightforwardly folded into cyclic one which was identical to the native peptide. in antimicrobial assay using a set of different bacteria all three studied defensins show activity preferentially against gram-positive bacteria including staphylococcus aureus but are inactive against gram-negative ones. the importance of disulfide bridges on tertiary structure of defensins and their antimicrobial activity will be presented. recently, the chemical structure and conformation of pseudodesmin a has been determined through x-ray diffraction and nmr spectroscopic analysis 1 . in this way pseudodesmin a was identified as a new member of the viscosin group of antimicrobial peptides (amps). in addition, it was demonstrated that individual molecules self-assembly in apolar environment into a supramolecular pore-like structure, providing structural support for its biological activity 2, 3 . to further explore the structure-function relationship, a viable synthesis strategy for pseudodesmin a analogues was developed, based on side-chain attachment of the first amino acid to the solid support, followed by stepwise fmoc solid-phase synthesis of the linear peptide precursor and on-resin head-to-tail cyclization. nmr study confirmed the molecular structure and thus the development of an efficient and successful synthesis of this type of amp's. these results and the synthesis route will be presented. trichogin ga iv, isolated from the fungus trichoderma longibrachiatum 1 , is the prototype of lipopeptaibols, a subclass of short-length peptaibiotics exhibiting membranemodifying properties. its primary structure is as follows: n-oct-aib 1 -gly-leu-aib-gly-gly-leu-aib-gly-ile 10 -lol, where n-oct is n-octanoyl, aib is α-aminoisobutyric acid, and lol is the 1,2-amino alcohol leucinol. this peptaibol is predominantly folded in a mixed 310-/αhelical conformation with a clear, albeit modest, amphiphilic character 2 . in this work, we synthesized by solution and solid-phase methodologies a set of trichogin ga iv analogs in which the four gly residues, lying on the poorly hydrophilic face of the helical structure, are substituted by one (or more) strongly hydrophilic lys residues. moreover, we synthesized another set of analogs where one (or more) aib residues are replaced by leu. the conformational preferences of these analogs were assessed by x-ray diffraction, cd, and 2d-nmr techniques 3 . we tested the role played by the substitutions on the peptide bioactivity, e.g. protease resistance, cytotoxicity, and hemolysis. cytotoxicity was tested using three in vitro cell-based assays: (i) human red-blood cells lysis; (ii) cell mortality in total human blood leukocytes and in separate subpopulations; (iii) cell mortality in three tumor-derived stable cell lines (hela, a541, and a431). our data show that some of our trichogin analogs are active against tumor cells, leaving the leukocytes unaffected. a convenient post-screening ring opening approach for the decoding of one-bead one-compound cyclic peptide libraries a. girard, e. biron* faculty of pharmacy, université laval and chuq research center, quebec, canada combinatorial chemistry has been widely used as an effective method for the generation and screening of synthetic peptide libraries. amongst the different combinatorial methodologies to discover new bioactive peptide-based compounds, we were particularly interested in the one-bead one-compound (oboc) approach 1 . this powerful approach fully exploit the great molecular diversity accessible with peptides and has been used to identify a great number of ligands and modulators for a wide variety of biological targets. however, its use with cyclic peptides is limited by difficulties in sequencing hit compounds by edman degradation or tandem mass spectroscopy due to the lack of free n-terminal amine and complicated fragmentation patterns, respectively. this problem has been overcome by pei and coworkers by using a bead segregation strategy in which the outer layer exposes the cyclic peptides and the inner layer the linear counterpart for sequencing 2 . more recently, lim et al. reported an elegant method to prepare and sequence oboc cyclic peptoid libraries without encoding by using a ring opening approach with triazine-based cyclic derivatives 3 . unfortunately this method is incompatible with amino acids bearing some functionalized side chains. based on this strategy, we have developed an efficient method to prepare oboc cyclic peptide libraries that does not require encoding by using a simultaneous ring opening/cleavage approach. the procedure is compatible with commonly used amino acids and allows rapid and efficient sequencing of selected hits after on-bead screening. the synthesis of an oboc cyclic peptide library, ring opening methodology and sequencing by mass spectrometry will be presented. cyclotides are a very abundant class of plant peptides that display immense sequence variability around a conserved cystine knot motif and a head-to-tail cyclized backbone conferring them with remarkable stability 1 . their intrinsic bioactivities combined with tools of peptide engineering make cyclotides an interesting template for the design of novel agrochemicals and pharmaceuticals 2 . however, laborious isolation and purification prior de novo sequencing limits their discovery and hence their use as scaffolds for peptide-based drug development 3 . here we extend the knowledge about their sequence diversity by analyzing the cyclotide content of a violet species native to western asia and the caucasus region 4 . using an experimental approach, which we named 'sequence fragment assembly' by maldi-tof/tof-based peptidomics, we were able to characterize novel cyclotides from viola ignobilis. amino acid sequencing of various enzymatic digests of cyclotides allowed the accurate assembly and alignment of smaller fragments to elucidate their primary structure, even when analyzing mixtures containing multiple peptides. using in-source decay and high energy collision induced dissociation of digested cyclotides allowed to distinguish isobaric residues ile and leu. overall this work underlines the immense structural diversity and plasticity of the unique cyclotide framework. the presented approach for the sequence analysis of peptide mixtures facilitates and accelerates the discovery of novel plant cyclotides. glycation is a nonenzymatic reaction occurring between reducing sugars and reactive amino groups of biomolecules. the reaction leads to a formation of a heterogeneous mixture of compounds which are classified as early, intermediate or advanced glycation end products (age). these compounds, especially advanced glycation end products, are involved in many pathological processes, mainly diabetic complications, and could be markers of certain diseases. detection of early products of glycation (amadori products) is a relatively easy task and can be performed by various methods including e.g. ms/ms techniques, isotopic labeling and affinity chromatography on immobilized boronic acid 1,2 . however, the diverse structures of ages make detection of these compounds more challenging. the aim of the study was testing a new method of ages identification based on isotopic 13 c labeling. a model protein (hen egg lysozyme) was modified with an equimolar mixture of [ 12 c 6 ]glc and [ 13 c 6 ]glc. then the glycated protein was subjected to reduction of the disulfide bridges followed by enzymatic hydrolysis. the obtained digest was analyzed by lc-ms methods. the glycation products were identified on the basis of characteristic isotopic patterns resulting from the use of isotopically labeled glucose. this method allowed for identification of 41 early maillard reaction products and 8 different structures of the glycation end products. isotopic labeling technique combined with lc-ms is a new and very sensitive method for identification of the advanced glycation end products even if their structures are unknown. this method could be also used as an alternative method of detection of amadori products. in the course of a project aimed to assess the significance of antibiotics for the producing organism(s) in the natural habitat, we screened a specimen of the fungicolous fungus hypocrea phellinicola growing on its natural host phellinus ferruginosus 1 . using a peptaibiomics approach 2,3 , we detected 19-and 20-residue peptide sequences by (u)hplc/hr-esi-qqtof-ms. structures of peptaibiotics found were independently confirmed by analyzing the peptaibiome of an agar plate culture of h. phellinicola cbs 119283 (ex-type) grown under laboratory conditions. notably, h. phellinicola could be identified as a potent producer of 18-, 19-, (culture) and 20-residue (specimen) peptaibiotics of the suzukacillin-type4. minor components of the 19-residue peptaibols, herein named suzukacillins c, are assumed to carry a c-terminal residue tentatively assigned as tyrosinol (tyrol). in addition, the previously isolated suzukacillin b 4 was sequenced and shown to be a microheterogeneous mixture of 11-residue peptaibols. in order to further investigate the significance of antibiotics for the producing organism(s) in the natural habitat, we screened specimens of the fungicolous fungus hypocrea pulvinata growing on its natural hosts piptoporus betulinus and fomitopsis pinicola 1 . using a peptaibiomics approach2, we detected 17-, 18-, 19-(major sequences), and 20-residue peptide sequences in the five specimens analyzed by (u)hplc/hr-esi-qqtof-ms. structures of peptaibiotics found were independently confirmed by analyzing the peptaibiome of pure agar cultures obtained by single-ascospore isolation from the specimens 1 . major, 19-residue peptaibols were assigned as deletion sequences of the trichosporins b3 lacking the ala/aib residue in position 3 . our results corroborate that: i) peptaibiotics are, indeed, biosynthesized in the natural habitat, thus, ii) their membrane-perturbing formation of ion channels may support the parasitic life style of a fungicolous fungus. based on methodology that we have developed in our lab 2 , we identified specific and selective substrates for these serine proteases. we used a 10,000 membered pnaencoded peptide library to screen 10,000 possible peptide substrates in a single experiment. the library was incubated with the protease of interest and then hybridized on a custom designed dna microarray. microarray scanning and data analysis allowed the measurement of the changes in fam/tamra ratios resulting from the protease activity and the determination of the protease specificity. to verify the predicted activity and specificity, fret peptides were synthesized, incubated with the enzymes and the hydrolysis reaction was followed by monitoring fluorescence emission. specificity constants kcat/km were calculated and the cleavage sites of the peptides were identified. dubs were, moreover, found to be associated with several diseases and as such are emerging as potential therapeutic targets 2 . several directions have been pursued in the search for lead anti-dub compounds. however, none of these strategies have delivered inhibitors reaching advanced clinical stages due to several challenges in the discovery process, such as the absence of a highly sensitive and practically available high-throughput screening assay 3 . in this study, we report on the design and preparation of a fret-based assay for dubs based on the application of our recent chemical method for the synthesis of ub bioconjugates 4 . in the assay, the ubiquitinated peptide was specifically labeled with a pair of fret labels and used to screen a library comprising 1000 compounds against uch-l3. such analysis identified a novel and potent inhibitor able to inhibit this dub in time-dependent manner with kinact = 0.065 μm and ki = 0.8 μm. our assay, which was also found suitable for the uch-l1 enzyme, should assist in the ongoing efforts targeting the various components of the ubiquitin system and studying the role of dubs in health and disease. 3 . more recent work based on rna interference experiments on a mouse model suggested that isoform-specific inhibitors against nmt1 might be effective anti-cancer agents as a knockdown of nmt1 inhibits the tumour growth, whereas knockdown of nmt2 has no effect 4 . if residual nmt2 activity can compensate for loss of nmt function in healthy cells, potential toxicity may also be minimised. we developed a method to identify peptide or protein substrates of nmt1 and/or nmt2. peptides/ proteins are exposed to nmt1 and/or nmt2 and an alkyne-tagged analogue of myristoyl coa. subsequent azide-alkyne "click" cycloaddition allows visualisation of the myristoylated substrates in fluorescence or chemiluminescence, using a fluorescent or a biotin moiety on the capture reagent. this labelling technology was applied to peptide libraries prepared on microarrays to investigate nmt1/2 isozyme substrate specificity using recombinant nmt1 and nmt2. peptides made of the first 8 or 15 amino acids at the nterminus of known myristoylated proteins were functionalised with a biotin moiety at the c-terminus and immobilised on an avidin-functionalised glass plate before being screened for activity. selective peptide substrates will be developed as isozyme-specific inhibitors and applied in cancer cell lines. using chemical proteomics and the labelling technology, a selective nmt1 or nmt2 inhibitor could also be used to identify protein substrates of one isozyme. for this purpose computer programs are created which can generate fragments of one compared structure and to reveal homology by their scanning along the amino acid sequence of another. our analysis was performed by comparing the primary structures of all possible protein fragments with the amino acid sequences of all presently known natural regulatory oligopeptides. the oligopeptides were extracted from the erop-moscow database1 which at the time of analysis contained data on the structures and functions of more than 10,000 natural oligopeptide regulators. the structure-function analysis was performed using a specialized software package. the input data were the complete amino acid sequences of the proteins used as a source of fragments with a specified length. then the initial sequence was fragmented in a stepwise manner. for example, in the case of dipeptide fragments, this procedure produced fragments with the following numbers of amino acids from the n-terminus -1-2, 2-3, and so on until the fragment that started at the second residue from the c-terminus. the cases when the amino acid sequence of a fragment coincided with part of the primary structure of a natural oligopeptide were recorded in the total protein chemical synthesis requires a case by case design and optimization which is governed by factors such as the solubility of the individual peptide segments, their primary sequence and in particular the presence of "difficult" amino acid residues at ligation junctions such as proline or the location of cysteines. usually, a subset of chemical tools are selected among a vast array of methodologies to match the specificities of the target protein. in this context, methods enabling the assembly of three peptide segments in the n-to-c and c-to-n direction play a central role and must be considered as complementary as they can be selected for building subdomains of the target protein. to date, most of the proteins were assembled in the c-to-n direction. only few methods are available for the n-to-c sequential assembly of proteins, whose design is highly challenging. we have recently reported that sea ligation, that is the reaction of a bis(2-sulfanylethyl)amido group (called sea) with a cysteinyl peptide, allows the formation of a native peptide bond in water and at neutral ph 1 . in this communication we will show that native chemical ligation and the unique chemical properties of sea group 2,3 can be combined in order to design a highly efficient one-pot three segments protein assembly procedure, working in the n-to-c direction 4 amylin is one of the most amyloidogenic peptides, its fibrils are responsible for causing type ii diabetes. amyloid formation mechanism is investigated both to find amyloid inhibitors as potential medical drugs, and to use amyloids as potential self-assembling biomaterials [1] . amyloid formation of amylin 10-29, its reverse and designed analogue beta-sheets and beta-sheet stacks was studied by molecular dynamics (md), amber 9.0, f99 force field. md revealed that for amylin 10-29 and its reverse analogue both the parallel and antiparallel beta-sheet and beta-sheet stack structures are stable suggesting that this could explain the high tendency of amylin to form amyloid fibrils. parallel amylin 10-29 beta-sheet stacks are kept together by two hydrophobic cores, while for the antiparallel system the dominating is the backbone hydrogen bonding between neighbor strands. also the bent form of the amylin 10-29 beta-sheet is stable. this is in concordance with transmission electron microscopy (tem) experiments stating that all three peptides, amylin 10-29, its reverse and designed analogues, exhibited significant fibrillar polymorphism [2] university of gdansk, poland molecular dynamics (md) of two peptides dlsfmkge (mk) and dlsfkkge (kk) not related to any known disease was run to investigate the mechanism of the amyloid formation. the parallel and antiparallel [1] betasheets of mk and kk peptides were simulated by molecular dynamics (md), amber 9.0, f99 force field, ntp protocol. it was found that antiparallel beta-sheets both of mk-and kk-peptides show much higher stability than the corresponding parallel beta-sheets. this md result was supported by atr-ftir spectroscopy [2] . the betasheet stacks built from six ten stranded antiparallel beta-sheets of mk-and kk-peptides: 10x6xmk and 10x6xkk, were subjected to md. it was found that the mk-system, 10x6xmk, is strongly kept together due to hydrophobic core built from two metionines, two phenylalanines and two leucines, but the kk-system, 10x6xkk, which differs only by one mutation m5k dissolves already at 20 ns of md run, because the separate beta-sheets don't hold togather in the betasheet stack due to lost hydrophobic core. the hydrophobic core of the mk-system consists of hydrophobic units centered on the two phenylalaninetwo metionine hydrophobic interactions, and two leucines from the both sides stabilize the unit. this mechanism could be used in amyloid based biomaterials. urokinase plasminogen activator (upa) is a serine protease involved in the metastasis of several tumor types. upa is therefore an interesting target in cancer therapy. upain-2 is a new analogue of a highly specific peptidic inhibitor (upain-1) of upa. the peptide contains twelve amino acids and is cyclized through the cysteines at its termini (s 1 -s 12cyclo-ac-cswrglenhaac-nh2). upain-2 inhibits upa with a ki of approximately 40 μm. 1 one method to improve binding affinity is multivalent exposure of the inhibitor, where the local concentration at the binding site is increased. fusion of upain-1 to the trimeric tetranectin showed improved binding affinity compared to the single peptide. 2 here, we report efforts towards novel chemically linked upain-2 peptides to allow multivalent display. the ki value of an upain-2 dimer, linked by a short peg chain through the n-termini, was almost halved compared to that of the single peptide (23 μm). this motivated us to explore the role of the site (n-or cterminal) and the size of the linking segment on the binding affinity. additionally, the influence of the number of upain-2 peptides in the molecule (two vs. four) was investigated by synthesizing a carboprotein that displayed four upain-2 peptides. we present two novel nmr spectroscopic approaches to study reversible self-assemblies in solution. both methods were applied on the self-assembling pseudodesmin a, a pseudomonas produced cyclic lipodepsipeptide that has the capacity to form pores in cellular membranes. 1, 2 the first method is based on the dependence of the 13 c α relaxation rate constants on the anisotropy of the assembly. 3 when the monomer conformation is known and the multiple ch bonds in the monomer sufficiently sample all orientations, the rotational diffusion coefficients can be assessed, revealing assembly shape information. in addition, the orientation of the monomer within the assembly is obtained. the second method is based on fitting translational diffusion coefficient data as a function of concentration in a model-free way, i.e. without assuming an oligomer shape beforehand. here, it is assumed that the diffusion coefficient's dependence on the oligomer size behaves as a power law, which dramatically simplifies the expression for the average diffusion coefficient (measured by pfg-nmr) as a function of concentration. the fitted value of the exponent of the power law fully embeds all shape information of the assembly, and may be related to the socalled fractal dimension of the oligomer. moreover, this approach reveals mechanistic information concerning the assembly formation. both methods thus allow structural information of the assembly to be obtained, even when there is little or no prior knowledge available on the mechanism of the selfassembly. nucleotides and α-amino acids are crucial building blocks for living organisms. these chiral molecules are the biosynthetically precursors of two of the most important classes of biopolymers, dna and proteins, respectively. the 3d-structures of biomolecules are currently studied using a variety of techniques, while helical handedness is routinely detected by means of light pulses of opposite circular polarization. the difference in the uv absorption of these two circularly polarized pulses is called electronic circular dichroism (ecd). in nature, biomolecules explore a wide range of conformations with intrinsically strong ecd signals in the 200-300 nm region, but these signals are essentially absent in the visible. nanomaterials such as metallic nanoparticles (depending on their sizes) display absorptions in the visible region but are achiral. as a result, when biomolecules are co-assembled with nanomaterials their chirality is transferred to create a plasmon-induced ecd signal in the visible region. in this work, we present our results which underscore the occurrence of moderately strong ecd bands in the range 300-550 nm resulting from a series of appropriately thiolfunctionalized peptide oligomers (based on alternating l-ala and aib residues) covalently anchored to 2-2.5 nm sized gold nanoparticles. we related the (positive or negative) signs of the ecd plasmonic signal with the oligopeptide length, that in turn is strictly associated with their secondary structure. this latter property was simultaneously monitored via ecd in the 200-250 nm range. we believe that in our systems a peptide-tometallic surface chirality transfer would take place. light can be controlled with high temporal and spatial precision. if a specific molecule is made light-sensitive, then a precise spatiotemporal control of some of its properties can be achieved. azobenzene is the most widely used photochromic group due to its propensity to pass reversibly from the cis to the trans state under irradiation with light of the appropriate wavelength. the cisand transazobenzene isomers exhibit different spatial arrangement of the aromatic moieties that give rise to significantly distinct physical and chemical properties. the design of novel azobenzene-based molecules with precisely placed photochromic groups able to induce photomodulation of macroscopic properties is currently attracting much interest. in this work, we explored the behaviour of the conjugate formed by linking each of the four hydroxyl groups of pentaerythritol to the carboxylic function of bis[p-(phenylazo)benzyl]glycine. this c α -tetrasubstituted α-amino acid bears two side-chain azobenzene groups. the resulting system exhibits tetragonal symmetry, with a total of eight azobenzene moieties, and can be viewed as a central core surrounded by a shell of azobenzene groups at the periphery. up to eleven (out of the possible fifteen) discrete states produced by sequential trans-to-cis isomerization of the individual azobenzene units have been observed depending on the time of exposure to uv-light. this process is fully reversible (cis-to-trans) under vis-light irradiation for several cycles. in addition, this compound has been shown to exhibit photomodulated physical properties, such as polarity and hydrodynamic volume. moreover, it shows a high propensity to self-assemble in aqueous solution, giving rise to supramolecular vesicles. light-scattering and electron microscopy experiments confirmed that a conformational reorganization of the vesicles can be triggered under exposure to uv or vis light. the total chemical synthesis of native or modified proteins is gaining increase importance in the study of protein function, but also in the development of protein therapeutics. it is usually achieved by assembling in water unprotected peptide blocks using so-called native peptide ligation methods. recently, our group has developed a novel native peptide ligation method based on a peptide featuring a bis(2sulfanylethyl)amido (sea) 1 group on its c-terminus in reaction with a cysteinyl peptide in water at ph 7. we will discuss in this communication the scope and limitations of sea native peptide ligation. for this, model sea peptides featuring all the possible proteinogenic amino acids were synthesized. their rate of sea native peptide ligation with a model cys peptide were determined in the absence of presence of guanidinium hydrochloride or other additives frequently used in ncl. we will present also experiments intended to clarify the mechanism of sea ligation such as the effect of ph on the rate of ligation, or the ability of the transient thioester sea form produced by in situ n,s-acyl shift to participate in thiol-thioester exchange 2,3 . overall, the data show that sea ligation is an interesting method for native peptide ligation at various x-cys junctions, and thus an interesting alternative to ncl. plga copolymers were used as the support for inducing controlled biomarkers releasing system. visualization of the penetration in the hippocampus of mice with confocal microscope was carried out by testing both peptide-free and peptide-bearing nanoparticles, previously labeled with the phthalocyanine fluorescent probe. the encapsulation degree of the larger (12-24) segment was less effective than the others thus stressing the importance of the peptide length to this internalization process. the results showed that all peptide-containing nanoparticles were able to cross the blood-brain-barrier thus indicating improved bioavailability and uptake for peptide delivery into the brain. in regard to the radiolabeling approach, the 99m tc radioisotope was used to label the peptide sequences at his residues, as previously described 3 . stable metal-peptide complexes were obtained in 10 -5 -10 -6 m peptide concentration range. noteworthy, higher metal labeling yield was achieved with peptide segments bearing his residues at peptide c-terminal position, thus pointing to a positiondependent effect for the 99m tc coupling reaction. in conclusion, the findings indicate potentials for the proposed encapsulation and radiolabeling strategies applicable for in vitro and in vivo diagnostic assays with these peptides for the study of amyloid plaques. we have used bifunctional short peptides (ac-cg n c-nh 2 , n=2, 4, 6) to selectively link gold nanorods in an end-to-end manner. additionally, we have manipulated the gap distance between the rods by changing the length of the peptide linker. the presence of the peptide in the gaps was shown by incorporating a propargylglycine residue in the sequence, which was detected with surface-enhanced raman spectroscopy (sers). the acetylene moiety will allow further chemical modification of the linker in the gaps, opening a wealth of interesting molecular systems to be placed and studies inside self-assembled nanogaps. 1 in this work, the fragmentation pathways of alitame, neotame and andvantame in comparison to those of aspartame and aspartame-d3, were studied by negative ion electrospray ionization (esi) high resolution mass spectrometry (thermo orbitrap mass analyzer). accurate mass spectra of the dipeptides allowed proposing specific fragment ions. neotame and advantame, which are the n-(3,3dimethylbutyl) and n-[3-(3-hydroxy-4-methoxyphenyl)propyl] derivatives of aspartame, presented similar fragmentation to that of aspartame. for neotame and advantame, the "diketopiperazine'' pathway seemed to be the major one, while a pathway resulting to the formation of a pyrrolidine-2,5-dione derivative, through the involvement of the side chain carboxyl group of aspartate, was also observed. for alitame, the "pyrrolidine-2,5-dione" pathway was recorded. similarities in the fragmentation using either orbitrap or triple-quadrupole mass spectrometry have been observed. elucidation of the fragmentation is very useful for the trace-level determination of the artificial dipeptide sweeteners in complex matrices. generation of silver nanoparticles in the presence of oligoproline derivatives p. feinäugle, h. wennemers* eth zürich, switzerland in the last years, the generation of silver nanoparticles (agnps) attracts, due to its unusual physical and chemical properties, more and more attention. agnps offer great opportunities for applications in molecular electronics, catalysis, imaging and for antimicrobial coatings. 1 the characteristics depend on their shape and size. 1 many efforts have been made to optimise the generation process by, for example, varying the reducing agents, which usually are used for the synthesis or using manifold additives which should guide the nucleation and also stabilize the resulting particles. nevertheless, the generation of agnps in defined sizes and shapes still remains a challenge. we address this goal by utilizing functionalized oligoprolines that form a conformationally well-defined and rigid helical secondary structure (ppii) 2 as additives. recently, we showed that by decorating this template with aldehydes which allow for in situ reduction of the silver, they act as scaffolds in the generation process and allow the formation of defined nanoparticles. 3 we will report the results of the generation of agnps with various oligoprolines as additives, which differ in the attached functional groups as well as in the length of the peptides. laser desorption/ionization mass spectrometry (ldi-ms) using specific inert surfaces to promote ion formation has been widely investigated the last decade [1] . in addition to porous silicon through the original dios technique, different materials were tested as potent ldi-promoting agents. we explored a variety of inert silicon-based uvabsorbing materials that were presenting different physico-chemical properties for the analysis of peptides [2] [3] [4] . both material architecture (amorphous powders, structured particles, structured surfaces) and material hydrophilic/hydrophobic character tuned by specific chemical derivatization (oxidation, silanization) were probed as crucial parameters for achieving efficient and robust detection of an home-made array of model peptides covering a wide structural and mass diversity. through this set of experiments, we were able to compare the performances of all investigated silicon-based supports, especially taking into account peptide detection sensitivity (down to femtomolar concentrations) and reproducibility/repeatability (intra-spot/inter-spot signal variations) as well as the method robustness using conventional maldi-tof/tof instrument. having illustrated the capability to achieve both peptide detection and sequencing on these ionizing surfaces in the same run, high-throughput identification of protein tryptic digests by a rapid ms profiling and subsequent ms/ms analyses was achieved. comparison of the ms and ms/ms data with those obtained with sample conditioned in organic matrix [5, 6] showed a great behavior for low mass responses demonstrating the capability of ldi on nanostructured silicon supports to be a complementary method to maldi in proteomic workflow. the dipeptides aspartame, alitame, neotame and advantame are low caloric artificial sweeteners. advantame 1 , which is the n-[3-(3-hydroxy-4-methoxyphenyl)propyl] derivative of aspartame, is the most recent among them. an application for its approval has been applied in usa, australia and new zealand. such sweeteners are used in food products and beverages and they can help in managing body weight and disorders like obesity and diabetes. 2 in this work, the simultaneous determination of aspartame, alitame, neotame and advantame by negative and positive electrospray ionization (esi), under hydrophilic interaction chromatography (hilic), is presented. advantame, neotame and intermediates were synthesized in our laboratories for the present application. the key-step for the synthesis of advantame and neotame was the reductive amination of h-asp(obu t )-phe-ome with 3-(3-hydroxy-4methoxyphenyl)propanal and 3,3-dimethylbutanal, respectively. the chromatographic behavior of the artificial sweetener dipeptides was studied on two hilic columns: kinetex hilic (a fused core silica column) and zic-hilic column (a sulfoalkylbetaine column). the separation of dipeptides was achieved on kinetex hilic using 5 mm ammonium formate buffer ph 3.5 / methanol / acetonitrile (15/10/75), with a flow rate of 100 μl/min at 50 o c column oven temperature. at this ph, silica is neutral and the dipeptides are in positively charged form. the retention mechanism of all analytes seems to be partition to the water layer as well as hydrogen bonding. 3 département de pharmacologie, université de sherbrooke, sherbrooke, qc, canada plasma and in vivo stability are essential requirements for the successful development of potential drug candidates or diagnostic imaging probes. rapid degradation of compounds in plasma may result in insufficient concentration to produce the desired pharmacological activity or to be used as a diagnostic agent. there are several strategies to improve plasma half life of peptides including pegylation, modification of nand cterminal fragments of peptide, replacement of labile amino acids, and cyclization 1 . we have previously reported on probes which specifically detect matrix metalloproteinase-2 (mmp-2) activity with magnetic resonance and optical imaging 2,3 . mmps are zincdependent endopeptidases degrading the extracellular matrix (ecm) and involved in cancer progression. the main goal of this work was to find more stable probes without sacrificing enzyme specificity. we have selected specific mmp-2 substrates 4 and their stability was evaluated in three different conditions: in plasma, in plasma with a mmp inhibitor and in a mmp-2 solution. the samples were analyzed by hplc to detect the degradation pattern of our compounds and by lc-ms to determine the molecular mass of peptide fragments. based on these studies, the most stable peptide was selected and incorporated in a solubility switchable probe with radiolabelled (68)ga-dota. its in vivo stability was estimated up to 30 minutes, making it a suitable candidate for further investigations. cancer of thyroid gland is the most common malignancy of the endocrine system. the treatment improvement could be achieved by early diagnosis. the aim of the study was to identify cancer specific markers using the libraries of artificial receptors immobilized on the cellulose. an array of supramolecular structures formed from n-lipidated peptides attached to cellulose via aminophenylamino-1,3,5-triazine was prone to formation of monolayer of "holes" and "pockets" in dynamic equilibrium. this selforganized structures were found capable of binding small guest molecules very efficiently recognizing the shape, size, and polarity of ligands, thus resembling arti cial receptors 1 . recognition and binding properties of guest molecules by artificial receptors depends mainly on the character of peptidic pockets and structure of the fatty acid. proper construction of the binding pocket allows selective binding components of mixtures of compounds from a living organism 2 . the preliminary data indicates that it is possible to construct an array of artificial receptors with diversified structures of peptidic pockets which are able to distinguish between components of homogenates from tumor and normal tissue. century. most of opioid alkaloids and their derivatives have μ-opioid affinity, while endogenous enkephalins are rather δ-than μ-selective. morphine is still the drug of choice for treating severe pain caused by cancer or surgical operation, but its side effects are the reason for the searching and development of new, selective mor agonists. the aim of our study is to choose within recently published crystallographic structures templates for homology modeling of the human μ-opioid receptor. we generated several models using different templates and all of them were evaluated by docking procedure (gold 5.1) ligands used in this investigation were synthesized and evaluated for their biological activity in our previous studies. they are enekphalin analogues with substitutions in second position. the best model of the human mu-opioid receptor was chosen according to data obtained from docking and in vitro biological activity of analogues and endogenous enkephalins. acknowledgments: this work was supported by nfsr of bulgaria project dvu 01/197 and cost action cm0801 project do 02-135/31.07.2009. pneumoniae, h. pylori, proteus sp. are considered as important factor contributory to development of rheumatoid arthritis (ra). the aim of this study was to investigate the level and specificity of antibodies binding to the synthetic peptides corresponding to the bacterial ureases "flap" region sequences in the rheumatoid arthritis patient's sera. for these investigations, peptides with amino acid sequences derived from "flap" regions of different ureases were synthesized using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium tetrafluoroborate 1 (dmt/nmm/bf4) as coupling reagent. peptides were immobilized on a cellulose membrane. the level of antibody binding as well as specificity of them was analyzed by quantitative dot blot method using sera 40 sera from rheumatoid arthritis patients (rap) and sera from 38 volunteer blood donors (vbd). the results of studies suggest that "flap" region may be involved in arising antibodies participating in autoimmunological processes but not to fight infection. this effect indicates that the peptides analyzed by us could be useful for investigation of ra pathogenesis. this suggestion was confirmed by the antibodies absorption experiment which indicates that specificity of antibodies present in rap serum is slightly lower in comparison with vbd serum. it has been found that antibodies present in rap serum recognize not only a specific peptide but also peptides containing fragments with different amino acid sequences. it means that immune system of rap is unstable and may produce a wide spectrum of antibodies recognizing not only a specific epitope but also a set of similar structures. autoantigen-specific t-cells also play a crucial role in the initiation and perpetuation of dsg3/dsg1-specific t-cell responses. t-cells recognize epitopes from dsg3 protein and produce different cytokines, e.g. interferon-γ (ifnγ). functional t-cell epitopes of dsg3 protein have outstanding importance in immunopathological research, development and the design of novel diagnostic tools. our previous studies have shown that certain t-cell epitope peptides are able to stimulate the peripheral blood monomorphonuclear cells (pbmc) of pv patients more effectively than those of healthy donors. our aim was to select a set of t-cell epitope peptides as potential synthetic antigens which are reliably able to distinguish between donors based on the in vitro t-cell stimulating activity. we have prepared synthetic dsg3 oligopeptides by fmoc/tbu solid phase methodology. after cleaving from the resin with tfa the peptides were purified by rp-hplc, and they were characterized by rp-hplc, mass spectrometry and amino acid analysis. pbmc of pv patients and healthy donors were isolated; and the cultures were stimulated by dsg3 peptides in a concentration of 0.025 mm for 20 hours, and the rate of ifnγ production was determined from the supernatants in sandwich elisa. synthetic dsg3 oligopeptides induced different in vitro ifnγ production rate on pbmc obtained from pv patients and healthy controls determined by elisa. our approach identified a synthetic antigen set as a promising biomarker for pemphigus vulgaris. [1] . in particular, cap2b (pelyafprvamide) has been shown to elicit antidiuretic activity in the green stink bug acrosternum hilare [2] , an important pest of cotton and soybean in the southern united states. analogs of cap2b containing either an (e)-alkene, cispro or a transpro isosteric component [3] were synthesized and evaluated in an in vitro stink bug diuretic assay, which involved measurement of fluid secretions of malpighian tubules isolated from a. hilare [2] . at a concentration of 1 μm, the conformationally constrained transpro analog demonstrated significant antidiuretic activity, whereas the cispro analog failed to elicit any activity. the results provide strong evidence for adoption of a trans orientation for the pro in cap2b neuropeptides during interaction with the receptor associated with the antidiuretic process in the stink bug. the work further identifies a scaffold with which to design biostable mimetic cap2b analogs as potential leads in the development of environmentally favorable pest management agents capable of disrupting cap2bregulated diuretic systems. the enkephalins are pentapeptides (tyr-gly-gly-phe-met/leu) with a proven antinociceptive action. it is believed that the interaction between them and the lipids composing the membranes is important for converting the peptides into a "bioactive" conformation 1,2 . using langmuir's monolayer technique the interaction of a synthetic methionine-enkephalin (met-enk) and its amidated derivative (met-enk-nh2) with mixed lipid monolayers composed of palmitoleoylphosphatidylcholine (popc), sphingomyelin and cholesterol was studied. the surface pressure-area (π-a) isotherms with regard to πmin, π max and the hysteresis curve shape of the pure lipid monolayers and after the addition of the respective enkephalins were detected. in addition, by using brewster angle microscopy (bam), the surface morphology of the mixed lipids-enkephalins monolayers were determined. our results suggest that there is a strong penetration effect of the enkephalins studied into the mixed monolayers. moreover, our results demonstrate the potential of lipid monolayers formed in langmuir's through in combination with bam to be successfully used as an elegant and simple membrane models to study lipid-peptide interactions at the air/water interface. acknowledgments: this work was supported by bulgarian ministry of education, youth and science, projects n do02-107/08, drg 02/5 and my-fs-13/07. dept pharmacolgy, temple univ, philadelpha, pa 19140, usa bioinformatic algorithms has predicted the existence of several potential hormone-like peptides transcribed from the ecrg4 gene 1 . previous publications indicated a highly level of gene expression of ecrg4 products has been found in the pancreas 1 , choroids plexus, epithelial cells, leukocytes, and macrophages 2 . however, the presence in the hypothalamus and the major form of derived peptides in each tissue haves not been clearly identified. knowingledge of the precise peptide generatesd within a given tissue is essential to understanding its functions. we have generated the peptide specific antibodies to against ecrg4-derived pprepro-augurin(71-147) and developed a specific ria kit for the quantification of the such peptide in question. a method for the purification of endogenous ecrg4-derived peptides from bovine hypothalamus also has been established. using ria to monitor the immunoreactive fractions and maldi-tof to identify the endogenous peptides, we foundhave detected the presence of ecrg4 derived molecular of bovine preproaugurin(71-147) from the homogenates of bovine hypothalamus. immunohistochemistrycal staining by antibody aalso confirmed the presence of thee peptide in some of the hypothalamic cells. of hypothalamus. the amount of prepro-augurin(71-147) in the hypothalamus although not soas high as pancreas, but is one third of the augurin level of the pituitary. conclusions: the native peptide derived from augurin preproteinecrg4 has been discovered.identified. we have confirmed the property of purified peptide,s prepro-augurin(71-147), along with the synthetic peptide standards. the present study provides the necessary procedures such as the elution from (1) c18 column, (2) p6 sizing column, and (3) a further purification conditions for hplc in order to enhance the immunoreactivity from tissue fractions and yield enough amount for identification. this dsip-related peptide (kn-dsip or knd) differs from dsip by only 2 amino acid residues in positions 2 and 5. we do not consider the homology between dsip and knd as accidental, bearing in mind functional significance of histone demethylases of the jmjc-group. methylation-demethylation of histones is known as an important mechanism of posttranslational modification playing a prominent role in epigenetic regulation of chromatin structure and gene transcription. dsip is also known as an effective "normalizer" and protector from homeostatic disorders induced by stress related disturbances. we suggest that histone demethylase of the jmjc-group containing dsip-related region can be considered as a possible protein precursor of endogenous peptides with dsip-like activity. in order to test our hypothesis we synthesized knd and studied its biological effects. in a preliminary assay cited below [1] knd showed similar and probably more pronounced effects than dsip as an agent that stimulates endurance and stress-resistance of animals in the forced swimming test. also knd provided a more active detoxifying action after administration of a semi-lethal dose of the cytostatic agent. in the present work we assessed neuroprotective and antioxidative potency of both peptides in vivo and confirmed the higher efficiency of knd. this study is supported by the moscow government. is a tridecapeptide (pglu 1 -leu 2 -tyr 3 -glu 4 -asn 5 -lys 6 -pro 7 -arg 8 -arg 9 -pro 10 -tyr 11 -ile 12 -leu 13 ) highly expressed in the central nervous system. this peptide elicits an analgesic response following peripheral or central administration. importantly, nt exerts a more potent analgesia than morphine at an equimolar dose, without having the associated side effects of opioid drugs. 1 structure-activity studies have identified the c-terminal fragment nt(8-13) as the biologically active minimal sequence. however, nor the full or truncated peptides cross the blood-brain barrier (bbb), thus hampering its clinical development. the substitution of pro 10 by an unnatural amino acid silaproline 2 (sip) increased bioavailability and plasma stability. structural properties conferred by the pro 10 were also retained as determined by nmr and ir. 3 aiming at delineating the mode of action of cl, three new cl derivatives bearing suitable labeling moieties, i.e the fluorescent molecule fitc, the streptavidin-counterpart biotinyl-group and the 99m tc-radiometal chelating unit dimethylgly-ser-cys, were designed, synthesized, purified, and characterized to be applied in in vitro and in vivo evaluation studies. the structure of the cl derivatives in aqueous solutions was studied with nmr, in parallel and in comparison with the parent molecule cl, in order to examine whether the presence of the labeling moieties has induced changes to the structure of the biologically active part of cl. cell survival assays with cl and the cl derivative bearing the fitc moiety were conducted in the pc12 cell line in order to explore their rescue effect. in parallel, the cl derivative bearing the dimethylgly-ser-cys moiety was successfully radiolabeled with 99m tc and its stability was assessed over time in its synthesis reaction mixture and in plasma. this 99m tc-radiolabeled derivative was subsequently administered to swiss albino mice in order to determine the biodistribution of cl in the living organism and its route of excretion, a study that has not been carried out so far for any peptide of the humanin family. furthermore, the potential interaction of cl with β-amyloid peptide, the hallmark of ad pathogenesis, was explored with circular dischroism. the results of this multifaceted approach to the biological action of cl will be presented. institute of biochemistry and biotechnology, martin-luter university, halle-wittenberg, germany kinins, such as the nonapeptide bradykinin, are important mediators of various physiological and pathophysiological responses including inflammatory disease, asthma, rhinitis, cell division, pain, vascular permeability, allergic reactions, pathogenesis of septic and endotoxic shock. there are two types of receptors for kinins, known as b1 and b 2 . b 2 receptors are constitutively expressed in wide variety of cells and required entire bk sequence for recognition, while b1 receptors have normally very limited expression and respond to [desarg 9 ]bk. b 1 receptors gene is turned on following either tissue damage or inflammation. accumulated evidence indicates that most of the clinically relevant effects of bk are functions of b2 receptors this being the reason why research on their antagonists is a topic of great interest. in our previous study we described the synthesis and some pharmacological properties of four new analogues of bradykinin (bk), designed by substitution of position 7 or 8 of the known [d-arg 0 ,hyp 3 ,thi 5,8 ,d-phe 7 ]bk antagonist with l-pipecolic acid (l-pip) (both analogues were also prepared in n-acylated form with 1-adamantaneacetic acid (aaa)). our results showed that presence of l-pip in position 7 slightly increased antagonistic potency in the blood pressure test, but it turned the analogue into an agonist in the rat uterus test. replacement of thi by l-pip in position 8 also enhanced antagonism in the rat pressure test but preserved the antagonism in the rat uterus test. in the present study we continue our previous investigations to find structural requirements which in the case of bk analogues result in high b2 antagonistic activity. several new bradykinin analogues modified in their cterminus with d-pipecolic acid were synthesized using spps method. the biological properties of the analogues were assessed by their ability to inhibit vasodepressor response of exogenous bk in conscious rats and by their ability to inhibit the contractions of isolated rat uterus evoked by bk. acknowledgements this work was supported by the university of gdansk (ds/8453-4-0169-2). peptides with beta-turn structure in peptide/mhc complexes a. stavrakoudis department of economics, university of ioannina, greece major histocombatibility complex (mhc) molecules interact with small peptides and form complexes. in most of the cases, peptide's structure in these complexes is found in extended conformation. however, notable exceptions exist where the peptide forms a beta-turn structure. this happens mainly in the central part of the peptide in class i complexes [1] , or at the c-terminal of class ii complexes [2] . several peptide/mhc complexes were, derived with xray studies, were extensively subjected to molecular dynamics simulations [3] in order to investigate the stability of this turn-like structural feature and to explore the factors that possibly contribute to this stability. it was found that both intra-peptide and peptide/mhc interactions might be responsible for peptide's conformation. the peptides were found to undergo several structural transitions indicating conformational plasticity and not a completely rigid structure inside the mhc groove. the results might be of special importance in designing defective peptide vaccines and beta-turn pharmaceuticals. the heptapeptide met-enkephalin-arg6-phe7 (merf) with the sequence of yggfmrf is a potent endogenous opioid located at the c-terminus of proenkephalin-a (penk), the common polypeptide precursor of met-and leuenkephalin. our systematic bioinformatic survey revealed considerable sequence polymorphism at the heptapeptide region of different penk prepropeptides among 56 vertebrate animals. four orthologous heptapeptides with single or double amino acid replacements were identi ed among 15 animals, such as yggfmgy (zebra sh), yggfmry (newt), yggfmkf (hedgehog tenrek) and yggfmri (mudpuppy). each novel hepta-peptide, together with the mammalian consensus merf and metenkephalin, were chemically synthesized and subjected to functionality studies, using radioligand binding competition and g-protein activation assays in rat brain membranes [1] . equilibrium binding af nities changed from good to modest as measured by receptor type selective [ 3 h]opioid radioligands. the relative af nities of the heptapeptides reveal slight mu-receptor (mop) preference over the delta-receptors (dop). [ 35 s]gtpγs assay, which measures the agonist-mediated g-protein activation, has demonstrated that all the novel heptapeptides were also potent in stimulating the regulatory g-proteins. all peptides were effective in promoting the agonist induced internalization of the green uorescence protein-tagged human mu-opioid receptor (hmop-egfp) stably expressed in hek293 cells. thus, the c-terminally processed penk heptapeptide orthologs exhibited satisfactory bioactivities, moreover they represent further members of the so-called "natural combinatorial neuropeptide library" emerged by evolution. corticotropin releasing factor (crf) exerts most of its physiological and pathophysiological actions by interacting with its type 1 receptor (crf1) and activating different intracellular signalling pathways. the crf1 is a plasmamembrane protein, which belongs to the family b of g-protein coupled receptors (gpcrs) and like the other gpcrs consists of an amino-terminal extracellular region, a carboxyl-terminal intracellular tail and seven, mostly hydrophobic, membrane-spanning segments (tm1-tm7), connected by alternating intracellular (il) and extracellular loops (el). binding of crf and its related peptides, such as sauvagine, to the extracellular regions of crf1 is associated with receptor activation and subsequent activation of different g-proteins and regulation of diverse signalling pathways. using a mutagenesis approach in combination with a radioligand binding study we found that trp259 and phe260 in the second extracellular loop of crf1 interacted with the amino-terminal portion of crf and sauvagine. interestingly only the interaction of sauvagine with trp259 and phe260 is important for crf1-mediated stimulation of camp accumulation. in marked contrast the interaction between crf and the residues trp259 and phe260 was unimportant for the activation of adenylate cyclase. thus it is possible for trp259 and phe260 of crf1 to regulate distinct signalling pathways, or different sets of them, after their interaction with different peptides. we are now performing experiments to fully elucidate the signalling pathways that are regulated by the interaction of crf and sauvagine with trp259 and phe260. these studies will advance the development of crf1-selective selective signalling-specific peptides that would be extremely useful for the elucidation of the role of crf1 in many physiological and pathophysiological situations, and possibly for the treatment of several crf1-related diseases. thymus humoral factor gamma-2 (thf-γ2), an octapeptide, purified from crude thf, retains essentially all the biological properties of thf [1] [2] . it regulates clonal expansion, differentiation and maturation of t-cell precursors, stimulates the production of lymphokine, maitains the normalization of impaired ratios between helper(cd4+) and suppressor / cytotoxic (cd8+) subsets and augments il-2 production in spleen cells. thf-γ2 has a calculated molecular weight of 918 and has the following amino acid sequence: leu-glu-asp-gly-pro-lys-phe-leu. its poor stability towards protein enzyme limits its extensive application. with the inte ntion to promote its bioavailability, bioactivity and develop ideal immunoregulatory drug candidat, four series of derivatives of thf were designed and synthesized: 1. n-and cterminal acylation. 2.restitution the flexible segment gly-pro by unnatural amino acids 6-aminohexanoic acid (aca) in order to shorten the synthetic steps and simultaneity improve the bioavailability and biostability of peptide; 3. reserve protected group of some amino acid residus as spot mutation. 4. mannich-based cyclization was carried out on resin [3] , phe was replaced by tyr serving as the active hydrogen component, a proline was introduced at the n terminal as the amine component and formaldehyde was used as the only component in solution. the bioactivity of synthesized products were detected. the leukocytopenia model in mice was induced by cyclophosphamide intraperitioneal injection. white blood cell count, thymus index and spleen index were detected to evaluate the immune function of compounds in mice. the results show that those compounds play a significant role in improving immune function in mice. the activity of compound lhl21 and lhl22 are also better than authentic compound tp-5 and tα1. marine organisms have been recognized as a promising source for the development of new pharmaceuticals. in the course of screening for antitumor substances from marine organisms, we found cyclic peptides containing many nonribosomal amino acids such as hydroxyasparagine, hydroxyleucine, or other supporting a hydrophobic side chain that were shown to be a key element for their biological activity. the laxaphycine b, a cyclic lipopeptide isolated from marine cyanobacteria anabaena torulosa harvested in french polynesia 1 constitutes an example of this peptide class. this compound has attracted our attention because of its micromolar cytotoxic activities on different cancer cell lines as well as its antiangiogenic properties which seems to be due to an interaction with the vegf receptor-1 2-3 . the synthesis of the non-natural amino acids 4-5 and of laxaphycine b analogues will be presented along with their preliminary biological activities. immune response suppressors are used in the medical praxis to prevent graft rejection after organ transplantation and in the therapy of some autoimmune diseases including dermatology. cyclolinopeptide a (cla) c(pro 1 -pro 2 -phe 3 -phe 4 -leu 5 -ile 6 -ile 7 -leu 8 -val 9 -), a cyclic, hydrophobic nonapeptide isolated from linseed, possesses strong immunosuppressive and antimalarial activity. 1 it has been suggested that both the pro-pro cis-amide bond 2 and an 'edge-to-face' interaction between the two aromatic rings of adjacent phe residues 3 in tetrapeptide unit are important for biological activity. this edge-to-face interaction can be influenced when phenyl rings are replaced by naphtyl substituent. in this communicate new analogues of cla modified by 2naphtylalanine (2-nal) in positions 3 or 4 or both 3 and 4 (1-3 linear analogues, 4-6 cyclic analogues) will be presented. the synthetic strategy and biological activity as well as conformational analysis will be evaluated. the onset of type ii diabetes mellitus (t2dm) coincides with the deposition of fibrillar material in the islet of langerhans in the pancreas that is a clinical hallmark of more than 95% of patients suffering this disease. 1 the main component of the pancreatic amyloid deposits is a 37-residues polypeptide hormone called islet amyloid polypeptide (iapp) or amylin. 2 in this work we have examined, by means of cd spectroscopy and tht-fluorescence, the conformational polymorphism of both full-length 1-37 hiapp, and the related fragment hiapp17-29, and compared the results with the respective rat counterparts. moreover, the cytotoxic activity was determined toward different pancreatic β-cells lines in the attempt to correlate iapp's fibrillogenic properties with the ability to mediate cell death. together the results suggest that β-sheet conformational transition, that generally preludes to fibril formation, is not a prerequisite for eliciting toxicity toward β-cells cultures. interestingly, confocal microscopy indicated that both hiapp1-37 and hiapp17-29 can enter the cell and might exert their toxic action at intracellular level. acknowledgments: this work was supported by miur, firb-merit project rbne08hwlz. due to its physiological functions, 26s proteasome is considered the target molecule in overcoming several diseases [1] . its core particle 20s has three types of active sites: chymotrypsin-, trypsin-and caspase-like. many natural and synthetic compounds were tested for their ability to inhibit proteasome. a recent report describing the inhibition of 20s by the serine proteases inhibitor -bovine pancreatic trypsin inhibitor -was considered by us with great attention [2] . our scientific interest is focused on peptide inhibitors and their interaction with serine proteases. sunflower trypsin inhibitor (sfti-1) is the smallest and the most potent peptide inhibitor in the bowman-birk family. owing to its size and the rigid structure (disulfide bridge and "head to tail" cyclisation) sfti-1 is willingly chosen as the lead structure in the search for new inhibitors [3] . its sequence is shown below (lys 5the p1 residue responsible for specificity): & 1 gly-arg-cys(& 2 )-thr-lys 5 -ser-ile 7 -pro 8 -pro-ile-cys(& 2 )-phe-pro-asp& 1 since native sfti-1 is not able to inhibit 20s [2] , we have designed its monocyclic analogues (with disulfide bridge only) with lys or arg in position 5 (p 1) and at least one basic amino acid (lys or arg) in positions 7 (p 2') and/or 8 (p3'). all analogues inhibit chymotrypsin -(ic50 at the range of 1÷3 μm) and caspase-like (ic 50 at the range of 0.7÷7μm) activities in vitro, whereas their activity towards trypsin-like specificity is much weaker. in several rat tissues, our view on ras has changed. metabolism of the ang-(1-12) may represent alternative pathway of ang ii formation, importantly, independent on renin and ace activity 1,2 . ahmad 2 et al. have described metabolism of ang-(1-12) by human atrial tissues and showed that ang ii is formed mainly by chymase. this renin-inependent ang ii production could explain the "resistance" regarding use of ace inhibitors in patients with hypertension or diabetic nephropathy. noteworthy, the role of ang-(1-12) in circulation is still unclear and there are no information about possible pharmacological modulation of its metabolism. in our study, we compared the ex vivo metabolism of angiotensinogen (fragment 1-14) in hypertensive (shr) and normotensive (wky) rats in organ bath of aorta and heart using lc-ms method 3 . surprisingly, we identified ang-(1-12) formed via reninindependent pathway to be a main product of angiotensinogen metabolism in rat aortic tissue and heart. in this setting, ang-(1-12) appeared to be not only prevalent metabolite of angiotensinogen, but also served as a substrate for generation of ang i and ang ii. as compared to wky rats, formation of ang ii, from ang-(1-14), was much higher in shr aortas but not in the heart. the functional consequences of these findings require further investigation. this study was supported by the grant n n401 293939 polish ministry of science and higher education. the lysosomal cysteine protease cathepsin c (cat c), also known as dipeptidyl peptidase i (dppi), activates a number of granule-associated serine proteases with proinflammatory and immune functions by removal of their inhibitory n-terminal dipeptides. activity of this protease is associated with several pathologies in human body [1] . in this work the characterization of cat c specificity using combinatorial chemistry methods will be described. the main goal of this work was to determine of substrate specificity of the prime region of this enzyme. the chemical synthesis and deconvolution of two libraries will be described. the hemostatic mechanism has the crucial role to prevent loss of blood from injured blood-vessels. this loss is prevented by the integrity of the vessel walls, by platelets aggregation or by blood coagulation, which in normal conditions is limited onto the local trauma of the vessel wall. in generally, the blood coagulation mechanism is important for maintaining vascular integrity and thus for the precaution of an organism from bleeding, which may also occur by blood coagulation caused by thrombin production. the diversion rate of this production leads to an expansion of thrombin to the general blood circulation. thus, when thrombin generation is not controlled by the mechanisms of inhibition, a widespread undesirable intravascular thrombosis is occurred. the whole process of platelets adhesion requires the presence of clotting factor viii (fviii), a necessary for the blood coagulation cascade glycoprotein, which takes part in the intrinsic pathway and acts as a coenzyme for the activation of factor ix, a serine protease depended on the thrombin production. the target of the present research is the synthesis of biologically active cyclic, head to tail, peptides, analogs of the sequence 558-565 of a2 subunit of fviii, which are potentially capable to block fviiia-fixa complex, reducing the thrombin production and thus the blood coagulation. the synthesized peptides are investigated for their inhibitory activity and tested for clotting deficiency by measuring the chronic delay in the activated partial thromboplastin time (aptt) and the reduction of the % value of the fviiia, which they generate in samples containing recombinant fviiia, in vitro. the blood coagulation is part of an important host defence mechanism, which under pathological conditions results in inappropriate intravascular coagulation when thrombin is produced. clotting sequence is the result of a cascade of two biochemical pathways, intrinsic pathway, so called because all components are present in blood, and extrinsic pathway, in which tissue factor is required in addition to circulating components. the activated form of factor viii (fviiia) is a key component of the fluid phase of the blood coagulation and plays an important role formatting a trimolecular complex with factor ixa, ca 2+ and negatively charged phospholipids of the cells membrane. this complex is called tenase and participates in activation of prothrombin, which acts on fibrinogen to generate fibrin monomer, polymerized rapidly to form fibrin clot. the fviii is comprised of a heavy (a1-a2-b) and a light (a3-c1-c2) peptide chain, both cleaved by proteases at three sites, resulting in alteration of its covalent structure and conformation. its deficiency is known as haemophilia a. our research effort is focused on the synthesis, identification and biological evaluation of peptide analogs, expected to inhibit selectively the increasing of thrombin production. their sequence is based on the regions in which the fviii interacts with fix, specifically on the sequence 558-565 of the a2 subunit. the synthesized peptides are examined for their activity and tested for clotting deficiency by measuring the chronic delay in the activated partial thromboplastin time (aptt) and the reduction of the % value of the fviiia, which they generate in samples containing recombinant fviiia, in vitro. inhibitor with the following structure: ac-llllrvkr-nh2, which has potent effects on the proliferation of prostate cancer cells. the potency and stability of this compound was subsequently enhanced by substitution of arg residue in position p1 with its conformationally restricted mimetic -4-amidinobenzylamine (amba). nevertheless, the specificity toward pace4 was significantly reduced by this modification. thus, in order to improve its selectivity without sacrificing inhibitory potency we decided to use positional scanning approach. in this study we present synthesis of two series of peptide libraries, which were designed by substitution of leu in the p5, p6 position of our control peptide (ac-llllrvkr-amba) with each of nineteen amino acid residues in order to verifying its influence on activity and selectivity of the resulting analogues. all peptides were synthesized by a combination of solid phase peptide synthesis and solution synthesis and tested for their inhibitory potency against furin and pace4. the p2-p8 fragments were synthesized by fmoc/tbu spps strategy on hydrazinobenzoyl or acid labile 2chlorotrityl chloride resin. then coupling of the 4-amidinobenzylamine · 2 hcl was performed. the best modifications were combined to give as several multipoint substituted inhibitors. we believed that our work, will provide new important information about structure-activity relationship of these class of analogs in order to obtain potent and highly specific pace4 inhibitor. institute for research in biomedicine, parc cientific de barcelona, barcelona -spain a bacterial toxin-antitoxin (ta) system is composed of two genes organized in an operon encoding a toxin and an antitoxin that regulate the growth and death bacterial cell under various stress conditions. the operon parde encode a ta system formed by pare toxin and its antitoxin pard. pare is a 12 kda protein that inhibits dna gyrase activity and thereby blocks dna replication. however the pare-gyrase interactions and the gyrase activity inhibition mechanism have not been explored. as an approach for understanding of this mechanism and to elucidate the pare region responsible for protein-protein interactions we have designed and synthesized a series of linear analogues of pare and investigated the ability of peptides to inhibit dna topoisomerases activity. so, based on structural data inferred from pare three-dimensional model 1 , 12 peptides were synthesized by solid-phase method. four peptides (parelc3, parelc8, parelc10 and parelc12), showed complete inhibition of dna gyrase supercoiling activity, by gel electrophoresis assay 2 , with an ic100 of 20 to 50 μmol.l -1 . in addition, intrinsic fluorescence and fluorescence anisotropy assays showed that inhibition process must occur by interaction with the gyra subunit. differently of wild type pare, the peptide analogues were able to inhibit the dna relaxation of topoisomerase iv with lower ic100 values. interesting was that only parelc12 displayed inhibition of the relaxation activity of human topoisomerase ii. our results suggest a new class of molecules with simultaneous inhibitory activity in dna gyrase and topoisomerase iv. furthermore, we have obtained the first example of a synthetic peptide from a bacterial toxin with inhibitory activity on human topoisomerase ii. institute of experimental endocrinology, slovak academy of sciences, bratislava, slovakia the renin-angiotensin system (ras) has long been recognized as an important regulator of systemic blood pressure and electrolyte homeostasis. our understanding of ras has experienced remarkable change over the past two decades. besides, angiotensin ii, the new biologically active peptides [e.g. ang-(1-7), ang-(1-12), ang iv, ang-(2-10)] and pathways [e.g. angiotensin converting enzyme 2 -ace2] have been described 1 ; some of them, like ang-(1-7) may oppose many actions of ang ii. importantly, despite all components of classical ras are found in adipose tissue 2 , the data about fat formation of various angiotensins remain scarce. in our study, we compared the ex vivo metabolism of angiotensinogen, ang-(1-12) and ang i in hypertensive (shr) and normotensive (wky) rats in organ bath of retroperitoneal and periaortic fat tissue using lc-esi-ms method. additionally, qpcr measurements of mrna expression of main enzymes involved in ang i metabolism were performed. both in the periaortic and epidydymal fat, the formation of ang-(1-7) was higher than production of ang ii. fat tissue formation of two main ang i conversion products, ang ii and ang-(1-7), differed significantly between shr and wky rats. compared to wky rats, the formation of ang-(1-7) in periaortic fat tissue was decreased in shr. in opposite, in epidydymal fat tissue formation of ang-(1-7) and ang ii was higher in shr. interestingly, there were no differences in aorta formation of ang ii and ang-(1-7) between shr and wky rats. our results suggest that in hypertension visceral fat production of angiotensin peptides is increased, while generation of "beneficial" ang-(1-7) in periaortic fat is decreased. however, the functional importance of such finding require further investigation. department of chemistry and biochemistry, university of washington, usa phospholipases a2 (pla2) are a superfamily of enzymes involved in various inflammatory diseases. 1 in particular, human secreted giia spla2 is an attractive target for the development of novel medicines. 1 we have shown that 2oxoamides based on γ-or δ-amino acids are potent inhibitors of cytosolic giva pla2. very recently, we have demonstrated that a long chain 2-oxoamide based on (s)leucine displays inhibition of human and mouse giia spla2s (ic50 300 nm and 180 nm, respectively). 2 a combined experimental/computational study was undertaken to further understand the role of the α-amino acid of 2-oxoamides for the inhibitor-enzyme binding. the crystal structure of giia spla2s reveals a highly conserved ca 2+ -binding loop and a catalytic dyad consisting of his47/asp91. 2-oxoamides based on hydrophobic αamino acids showed better binding score prediction compared to polar α-amino acid derivatives. a number of new 2-oxoamides based on α-amino acids were synthesised and tested for their inhibitory activity against giia, gv and gx pla2. the 2-oxoamide based on (s)-valine displayed potent inhibition of giia spla2 (ic 50 218 nm) in accordance with the predicted docking score. docking results reveal that (s)-valine-based inhibitor forms key interactions with the active site of the enzyme. the carboxylic group participates in a hydrogen bonding with gly31 and lys62, and 2-carbonyl group with gly29. furthermore, both carbonyl groups are in the proximity with ca 2+ . the side chain of (s)-valine adopts a suitable orientation to interact with tyr51 and lys62. the long aliphatic 2-oxoacyl chain is accommodated in the hydrophobic region of the active site and creates proximal contacts with leu2, ile9, his6 and phe5. the search for novel classes of pharmaceutical molecules with enhanced therapeutic power has been the subject of numerous research groups all over the world. moreover, systems of immobilization and controlled release which are adapted to these new classes of molecules, has proven to be an area of extreme importance to provide the same therapeutic efficacy. using solid-phase chemistry a series of ccdb toxin analogous peptides were synthesized and were synthesized and tested against the capacity of inhibition of bacterial enzymes dna gyrase and topoisomerase iv (topo iv). subsequently those peptides were detained in drug delivery systems (dds) to be tested against the inhibition of growth of different bacterial species. in this data we could observed that the analogue ccdbsg2 could inhibit only dna gyrase and not the topoisomerase iv. in the other hand the analogue ccdbsg1 presents a hard inhibition potential against topo iv specially because of their structural difference. is possible conclude that topoisomerase iv presents the tertiary structure very similar to dna gyrase, but those mechanisms of action must be clearly distinct 1 . in the in vitro studies, as expected, results revealed that the drug delivery systems are the key to the power efficiency of peptide analogues against the bacterial growth inhibition which cannot be observed when the peptides are free in solution. some of the different lipid compositions of the dds are demonstrating to be more efficient in the membrane cell transverse and this data previously assumes that it is possible to apply different types of dds to promote the peptide molecules transport across the cellular membranes according to several specific therapies. with this studies we have obtained more knowledge about the interaction system of enzyme-toxin and hopes which helps in future studies to development a new antimicrobial molecules class. it is urgent to develop less toxic and more efficient treatments for leishmaniases and trypanosomiases. we propose to target an ancestral form of the proteasome, the hslvu protease, which is present in the parasite's single mitochondrion, essential for the growth of these organisms and has no analogue in the human host. originally discovered in eubacteria, this complex is constituted by two central hexameric hslv protease rings sandwiched between two hexameric hslu atp-ase rings. as hslv shares a similar enzymatic mechanism with the host proteasome, we propose to inhibit the assembly of the complex in order to be selective. according to studies on bacterial hslvu, 1,2 the c-terminal segment of hslu is essential in hslv activation and in complex assembly, therefore representing a privileged target. we produced recombinant hslv, which is inactive alone, and showed that a synthetic c-terminal hslu peptide was able to induce the digestion by hslv of a fluorogenic substrate that we developed. with this enzymatic test in hands, we started the characterization of the interaction of the c-terminal portion of hslu with hslv. we will present the results obtained with various series of analogues of the original c-terminal hslu peptide, including truncated forms, ala scan, constrained analogues and multivalent constructions. helped by molecular modelling studies, the aim is to establish structural requirements, which could lead to high affinity and stable ligands able to inhibit the interaction between the hslu and hslv rings, obligatory for the degradation of proteins by the hslvu complex. finally, we checked that hslv was inhibited by classical active-site directed proteasome inhibitors like bortezomib. f. babos a,d , e. szarka b , gy. nagy c , z. majer d , g. saŕmay b , a. magyar a , f. hudecz a,d citrullinated filaggrin peptide (ccp) were detected in ra sera and anti-ccp positivity is widely used for diagnostic purposes. identification of new epitopes of filaggrin 1 would be useful in the diagnosis of anti-ccp3 seronegative patients. in order to achieve optimal immune recognition of biotinylated epitope peptides it is important to analyse the effect of the labelling moiety on antibody binding. for these studies 5-as well as 19-mer peptides with nor c-terminal biotin were synthesised manually by spps, using fmoc/ t bu strategy. biotinylation was performed by using biotin, biotinyl-6-aminohexanoic acid or 4,7,10-trioxa-1,13-tridecanediamino succinic acid linker 2 modified biotin. labelled peptides were used in an indirect elisa, on neutravidin pre-coated plates and the binding was detected by anti igg-hrp. to examine the role of the presence/position of biotin in the secondary structure of the peptides, electronic circular dichroism (cd) method was used. we found that the ccp3+ serum samples specifically recognized the c-terminally biotinylated 5-mer filaggrin peptides, while showed no binding with the n-terminally biotinylated compounds. in case of the 19-mer epitope peptides there was no difference between the recognition of nand c-terminal biotinylated analogues. data presented suggest that the position of the biotin in case of the short filaggrin epitope peptides markedly influence the serum antibody binding. upon activation process, they are released from the granules and then involved in immunoresponse of the organism. when out of the cell those enzymes remain in free form or become associate with the cell membrane. the physiological role of this proteases is manifestated in several processes such cytokine and chemokine processing, platelet activation, and degradation of extracellular matrix's proteins [1] . in this work results of the specificity of two members of nsps pr3 and hne evaluated using the combinatorial chemistry methods will be presented . both enzymes share primary specificity and to obtain the selective substrate that will be recognized only by one enzyme, the prime sites should be investigated. the general formula of the designed library is as follows: where in positions x1', x2' and x3', the set of 19 proteinogenic amino acids (except cys) was introduced. abz is 2-amino benzoic acid served as donor of fluorescence and 3-nitro-l-tyrosine as acceptor. eukaryotic proteasome is a highly organized protease complex comprising a catalytic 20s core particle (cp) and two 19s regulatory particles (rp), which together form the 26s structure. the main function of this large intracellular protease is to degraded ubiquitine labeled proteins. the catalytic particle of the proteasome displays three distinct enzymatic activities: trypsin-like, chymotrypsin-like and glutamyl-like. the increase activity of the proteasome is associated with several disease including cancer [1] . the main aim of this work is to synthesized the cell permeable fret displaying peptides that will selective cleaved by single proteasome activity. additionally each peptide when independently cleaved by the proteasome subunit, should emit the fluorescence energy in a different spectral region. our intention was designing substrates which would allow to monitor simultaneously (in a single experiment) and independently of three proteasome activities in this report, we will describe the chemical synthesis of several peptides modified at on cand n-termini by synthetic fluorescent amino acids the general formula of these peptides is as follows: where x is a non proteinogenic amino acid that serve as a donor of fluorescence, y amino acid that is a acceptor of fluorescence. the obtained fluorescent peptides were examined for their ability to cross the cell membrane. also kinetic parameters (k cat, km, kcat/km) with proteasome will be presented. approximately 100 dubs are encoded in the human genome and are involved in a variety of regulatory processes, such as cell-cycle progression, tissue development, and differentiation. recently, several groups have introduced various methods for linking ubiquitin to different substrates via nonhydrolyzable isopeptide bonds, which resist the action of dubs. using these methods, one could explore the function and the mechanism of dubs and apply them in activity based profiling. here we present a new and convenient strategy for preparing nonhydrolyzable ubiquitinated peptides and proteins by nmethylating the isopeptide bond. using this method we prepared several nonhydrolyzable ubiquitinated peptides with different lengths derived from ubiquitinated h2b and examined their affinity to different dubs. f.i. nollmann, c. dauth, d. reimer, h.b. bode* goethe universität, frankfurt, germany bacteria of the genus xenorhabdus and photorhabdus are gram negative gamma proteobacteria that live in symbiosis with nematodes of the genus steinernema. undergoing their partly entomopathogenic life cycle these bacteria not only produce antibiotics 1,2 and insecticides 3 but also several different small molecular compounds and peptides. 4 for the most part the biological benefits of these secondary metabolites have not fully been understood yet. 5 with the help of inverse feeding experiments, hr-ms and nmr as well as molecular engineering we were able to characterize and/or isolate some of these peptides. since they are mostly produced in trace amounts, we synthesized them in order to make them accessible to continuative testing. given that not only linear but also highly methylated or cyclic peptides are produced, the synthesis was quite challenging. nevertheless, we were able to establish in our laboratory a general synthesis route for cyclic peptides 6 and depsipeptides 7 , as well as highly methylated hydrophobic linear sequences. testing several of these peptides has revealed activity against insect cells and against the causative organisms of neglected tropical diseases. cyclotides are a large class of plant peptides defined by a head-to-tail cyclized backbone and three conserved disulfide bonds in a knotted arrangement. these unique structural features confer them with remarkable stability and due to a range of bioactivities they are extensively investigated as templates in drug discovery 1 . based on the use of oldenlandia affinis in traditional african medicine for its uterotonic principle we investigated crude plant extracts and semi-pure cyclotide fractions for the ability to induce uterine contractions using a collagen-gel contractility model2. pharmacological analysis of the effects led to the identification of the oxytocin receptor, a representative of the g-protein coupled receptor (gpcr) family, as a molecular target for cyclotides. mass spectrometry-based sequence analysis of 'active' fractions revealed cyclotides with high similarity to the human oxytocin (h-ot) peptide that exhibited weak binding to the human oxytocin receptor. we further analyzed synthetic cyclotide-derived small ot-like peptides and grafted the h-ot sequence into the stable cyclotide frame. these peptides showed increased binding and activation as compared to native cyclotides. these findings may open new avenues for the discovery of gpcr ligands from natural peptide sources. gpcrs are promising drug targets and ~5 0% of currently used drugs act via binding to these receptors. natural combinatorial peptide libraries are likely to play an important role in identifying novel gpcr ligands 3 . particularly plant cyclotides cover a large chemical space based on their high sequence diversity. together with their range of bioactivities and unique stable structure suggests that cyclotides are of current and future interest for drug discovery and development. acknowledgements: this work is funded by the austrian science fund fwf (p22889). drosha and dicer are two key endonucleases for biogenesis of micrornas (mirnas) that regulate target mrna. drosha converts pri-mirna to ~7 0 nucleotide (nt) pre-mirna in nucleus and dicer converts pre-mirna to linear ~2 2 nt single-stranded mirnas in cytosol. even though dicer is potentially important to control availability of mature trans-acting rnas in cytosol, the enzyme itself does not seem to be the suitable target controlling mirna processing due to the lack of its substrate specificity. nature, however, might be intelligent enough to differentiate a variety of pre-mirna, so that a certain specific pre-mirna is converted to mature mirna in case it needs. therefore, other component(s) in the enzyme complex could be involved in recognition of auxiliary proteins from out sources to give extra specificity. we have synthesized trp-containing amphiphilic peptides against several pre-mirna. peptide 2b showed a picomolar binding affinity and a large specificity against pre-let7a-1. in vitro mirna processing, dicer activity was also selectively enhanced in the presence of this peptide. on treatment with this peptide on hct116 colon cancer and p19ec cell lines, let7a-1 mirna was more processed than reference mirnas. the toxicity of furan is known to rely on its selective oxidation in the liver by cyt p540 enzymes transforming it into the very reactive butenedial, which quickly reacts with proximate nucleophiles. 1 this principle was used in our laboratory to develop a high yielding dna interstrand crosslinking methodology. 2 in view of the demonstrated site-selectivity, the method further holds promise for sitespecific crosslinking dna to its binding proteins, which is highly relevant in the study of transient protein-dna interactions. furthermore irreversible dna binding can be achieved through such a covalent linkage, which is potentially useful for new generation therapeutics. 3 the reactive furan moiety can in principle be incorporated either in the dna or in the protein. in the former case, a furan modified nucleotide was built into an oligonucleotide positioning the furan moiety at the periphery of the dna, to avoid interstrand crosslinking. for the latter approach, we initially chose to synthetically access a furan modified dna binding protein mimic. next to a previously described non-covalent gcn4 mimicking dimer, 4 we have also investigated a new type of steroid-based dipodal dna binders. 5 synthesis of the latter constructs has proven challenging in view of the immobilization of two peptide chains with helix forming tendency at close distance on the template. results, showing the power of microwave assistance will be discussed. in an alternative approach, a full length protein was modified with furan by amber suppression based on the structural similarity between a furan modified amino acid and pyrrolysine. 6 pharmaceutical institute, university of bonn, an der immenburg 4, 53121 bonn, germany human matriptase-2 is a 80 kda protein with trypsin like specificity. this protein exhibits a domain organization similar to family of membrane-bound serine proteinases known as type ii transmembrane serine proteinases. among many ascribed function in human body, this enzyme is a potent negative regulator of hepcidin, the peptide involved in iron homeostasis [1] . matriptase-2 has a similar fold as other tmsp members, however their detailed specificity still remain unclear. the aim of this study was to determine the substrate specificity of this physiological important enzyme using combinatorial chemistry approach. in order to characterize the matriptase-2 specificity, the tetrapeptide library with c-terminal amide of aminocoumarin (acc-nh2) that serve as a fluorophore, was synthesized. its general formula is given below: x4-x3-x2-x1-acc-nh2, where in position x4-x2 the set of proteinogenic amino acid residues are present, whereas in position x1 lys or arg was introduced. deconvolution of such library was performed using iterative approach in solution. the results obtained indicate that matriptase-2 display diverse p4-p2 specificity as compare to matriptase-1. the most efficient hydrolyzed amino acid residue in position p4 appear to be ile, that is followed by arg in p3 and ser in p 2 . the arg in position p1 is 30% faster hydrolyzed then lys. for selected substrates, the kinetic parameters (kcat, k m ) were determined. amyotrophic lateral sclerosis (als) is a chronic progressive disease. it is characterized by degeneration of upper or lower motor neurons, but its pathogenesis is still unknown and no effective treatment currently exists. it is known that antibodies to gangliosides have been found in some als patients, and these antibodies are also well known to be present in the patients affected by a variety of autoimmune diseases including multiple sclerosis. up to now anti-gangliosides antibodies are detected in clinical immunology laboratories using isolated non consistent antigen mixtures. therefore, we are interested in developing reliable and univocally characterized synthetic antigens for efficient antibody detection. csf114(glc) is a family of structure-based designed glycopeptides that we previously developed as multiple sclerosis (ms) synthetic probes. these n-glucosylated peptides are able to detect specific autoantibodies in the sera of an antibody-mediated form of ms. 1 autoantibody recognition was favored because of the exposition of the sugar amino acid on the tip of type 1' β turn structures. aim of this study is the introduction, in the type 1' β turn peptide structure, of the sugar moiety specific for anti-gangliosides antibody recognition by synthesizing specific building blocks. these building blocks are amino acids carrying glycans mimicking the biological activity of complex oligosaccharides. we selected sialic acids (in particular the n-acetylneuraminic acid -neu5ac) 2 because they are involved in a significant number of biological events. neuraminic acid and its derivates are widely distributed in animal tissues and in bacteria, especially in glycoproteins and gangliosides. therefore, we synthesized fmoc-l-asn(neu5ac)-oh and fmoc-l-ser(neu5ac)-oh. these building blocks will be introduced in the type 1' β turn structure for the detection of anti-gangliosides antibodies in als. as a distinct pattern of ms could involve an antibodymediated demyelination, identification of autoantibodies as specific biomarkers is a relevant target. even if interesting data focused on the diagnostic and prognostic role of the detection of antibodies to myelin oligodendrocyte glycoprotein (mog) in adults' serum, its value remains dubious due to many other contrasting results. our research group identified csf114(glc), an nglucosylated peptide, able to detect disease-specific autoantibodies in the sera of a statistically significant number of ms patients. 1, 2 since this synthetic antigen may be considered as a mimic of aberrant post-translational modification (i.e. n-glucosylation) of myelin protein(s) triggering autoimmunity in ms, our goal is to obtain the extracellular domain of mog properly glucosylated thanks to a simplified native chemical ligation approach. 3 for this purpose, the n-glucosylation will be introduced in a synthetic peptide fragment following the building-block approach by spps. the other protein fragment bearing an n-terminal cysteine will be expressed in e. coli after introduction of a selective point mutation into mog. finally, our aim is to test the semi-synthetic protein by sp-elisa to study the ability to detect autoantibodies in ms patients' sera and to find a potential cross-reactivity with csf114(glc). this peptide is an endogenous ligand of the opioid receptorlike 1 (orl1), previously referred to as "orphan" receptor, structurally and functionally related to the classical opioid receptors. also the hexapeptide ac-ryyrwk-nh2 is shown to be a selective ligand for the nop receptor with marked analgesic effect. with a view to developing ligands for the nop receptor with more potent analgesic activity, new series of the ac-rfmwmk-nh2 and ac-ryyrwk-nh 2 , modified at position 4 and 5 respectively with newly synthesized β 2tryptophan analogues were synthesized 1 . the aim of the present study was to examine the effects of naloxone (nal) and jtc-801 (nop receptor antagonist) in the analgesic activity of newly synthesized hexapeptide analogues. all peptides (10 μg/kg), nal (1 mg/kg) and jtc-801 (0,5 mg/kg) were injected intraperitoneally (i.p.) in male wistar rats. antinociceptive effects were evaluated by two nociceptive tests -paw-pressure (pp) and hot-plate (hp) and statistically accessed by anova. the results will be discussed compared to the referent compound in both tests used and mechano-and thermo-receptors are involved. [1] . socs1 and socs3 have many similarities as well as some intriguing differences. both can block signalling by direct inhibition of jak enzymatic activity yet apparently require different anchoring points within the receptor complex. while the primary socs1 interaction is with a critical py residue within the jak catalytic loop [2] it interacts also with py residues in the ifnαr1 and ifn r1 subunits in a jak1-independent manner; the socs3-sh2 domain also interact with y1007 in jak2, albeit with slightly lower affinity, but subsequent studies demonstrated a high affinity interaction with py residues located within receptor subunits [3] . mutagenesis studies identified small regions at the n-termini of the socs1 and socs3-sh2 domains, and at the c-terminus of the socs3-sh2 domain, which were critical for phosphotyrosine binding. in order to gain insights in molecular discriminants for the interaction of both socs1 and socs3 toward jak2 and tyk2 we designed and synthesized peptides encompassing regions involved in proteins recognition. we set up a spr assay to evaluate the affinities of complexes formation. then through an alascanning approach we have designed new peptide sequences containing un-natural amino acids that are able to better recognize wild sequences and whole proteins. cellular experiments on stat1 activation signaling suggest their potential application as modulators of disorders involving socss overexpression. targeting proapoptotic death receptors (drs) to trigger apoptosis in cancer cells is a promising anticancer therapeutic approach. trail (tnf-related apoptosis inducing ligand) is a transmembrane homotrimeric protein belonging to the tnf family that triggers selective tumour cell apoptosis upon binding to its cognate receptors dr4 and dr5. several strategies are being developed to exploit the unique cancer selectivity of the trail-dr pathway in therapy, including the use of recombinant trail targeting dr4 or dr5. [1] recently, a disulfide-bridged macrocyclic 16-mer peptide (derived from phage display) that binds selectively to dr5 has been identified. [2] oligomeric versions of this macrocyclic peptide display increased binding avidity to the receptor and exhibit the capacity to activate the trail apoptotic pathway both in vitro and in vivo. [3] however, disulfide bonds are susceptible to reduction and scrambling in vivo potentially resulting in the loss of the desired biological activity. among alternative linkages with increased redox stabilities, lanthionine thioethers, in which one of the sulfur atoms of the disulfide bond is removed have previously been introduced into biologically active peptides with some success. [4] disulfide bridges can undergo a -elimination in alkaline conditions, followed by a michael addition to give a thioether bridge. optimization of this reaction led to the desulfurized analogue of the dr5-binding peptide. the native dr5-binding peptide and its desulfurized analog have been compared for their structural (nmr conformational analysis) and biological properties (affinity to dr5 and signaling pathways). the apelin/apj complex has been detected in many tissues and is emerging as a promising target for a number of pathophysiological conditions. in the central nervous system, apelin/apj was detected in brain regions involved in spinal and supraspinal control of pain, such as the amygdala, hypothalamus, dorsal raphe nucleus and spinal cord. we propose the hypothesis that apelinergic agonists represent a potential new approach to pain modulation and that the synthesis of stable analogues would lead to compounds with antinociceptive properties. there is currently little information on the structure/activity relationship (sar) of the apelin hormone. in an effort to better delineate sar, we synthesized analogs of apelin-13 modified at selected positions with unnatural amino acids, with a particular emphasis on the c-terminal portion. analogs were then tested in binding and functional assays by evaluating gi/o mediated reduction in camp levels and by assessing β-arrestin2 recruitment to the receptor. the plasma stability of new analogs was also assessed. several were found to possess increased binding and higher stability compared to the parent peptide. there is compelling evidence that the neuropeptide 26rfa and its cognate receptor gpr103, are involved in the control of food intake and bone mineralization. 1 among the gpcrs whose structures have been solved, gpr103 exhibits the highest sequence homology with the beta2adrenergic receptor. the aim of this work was to experimentally characterize predicted ligand-receptor interactions by site-directed mutagenesis of gpr103 and design of point-substituted 26rfa analogs. starting from the x-ray structure of the beta2-adrenergic receptor, a 3d molecular model of gpr103 has been built. the bioactive c-terminal octapeptide 26rfa(19-26), kggfsfrf-nh 2 , 2 was subsequently docked in this gpr103 model and the ligandreceptor complex was submitted to energy minimization. in the most stable complex, the phe-arg-phe-nh2 part was oriented inside the receptor cavity whereas the n-terminal lysine remained outside. a strong intermolecular interaction was predicted between the arg 25 residue of 26rfa and the gln 125 residue located in the third transmembrane helix of gpr103. in order to study this interaction, we have investigated the ability of 26rfa and arg-modified 26rfa analogs to activate the wild-type (wt) and the q125amutant receptors transiently expressed in cho cells. the platelet receptor αiibβ3 plays a critical role in the process of platelet aggregation and thrombus formation. upon platelet activation its conformation changes leading to an increased affinity for fibrinogen. the αiibβ3 activation is regulated by "outside-in" and "inside-out" signaling. among the protein-protein interactions, which contribute to «inside-out» signaling, the most important is that of talin with the β3 cytoplasmic tail. it has been recently suggested that talin-mediated αiibβ3 activation relies on the cooperative interaction of the membrane proximal (mp) and the membrane distal (md) β 3 regions with talin f3 domain and that the -n 744 ply 747 -motif of β3, which can be phosphorylated at y 747 , plays a critical role in this process. 1 to evaluate the interaction of talin with the β3 tail of integrin we designed and synthesized three peptides corresponding to the md and mp parts of β3 in their carboxyfluoresceinlabeled form (md: cf-r 736 akwdtannplyke 749 -nh 2 , cf-n 743 nplykea 750 -nh 2 and mp: cf-k 716 llitihdrke 726 -nh2). emission and anisotropy fluorescence spectroscopy was used to quantitatively assess the affinity of these peptides for talin. furthermore, to challenge the role of the y 747 phosphorylation in talin-α iib β 3 interaction we also studied the binding of talin to the modified analogues of md, cf-r 736 akwdtannpl(ptyr)ke 749 -nh 2 and cf-n 743 npl(ptyr)kea 750 -nh 2 . our experiments revealed that the md and mp parts of β3 bind tightly to talin and that y 747 phosphorylation has an inhibitory effect on this binding. functionalized oligoprolines as multivalent scaffolds in tumor targeting p. wilhelm, h. wennemers* eth zurich, zurich, switzerland oligoprolines are known to be structurally well-defined molecular scaffolds. in aqueous media, even short chain lengths of six proline residues adopt a polyproline ii helix (ppii). this secondary structure is a highly symmetric helix where every third residue is on top of each other in a distance of about 9.5 å. [1] the incorporation of azidoproline (azp) allows facile and versatile functionalization either via copper-catalysed azide-alkyne cycloaddition (cuaac) or an acylation that followed a staudinger reduction. [2] based on the structural integrity of the oligoproline scaffold, targeting vectors can be conjugated via coppercatalysed azide-alkyne cycloaddition in defined distances. recent studies on radiolabeled oligoproline-bombesin conjugates, to target the gastrin-releasing peptide receptor (grp-r), showed in vitro and in vivo superior internalization in prostate cancer cells compared to the established monovalent ligands. [3] a facile route to synthesize alkynylated ligands has been developed successfully. we are currently expanding this concept to the integrinligand c(rgdyk) as well as to [tyr 3 ]-octreotide, which binds to somatostatin-receptors. the monovalent analogue of the latter, dota-[tyr 3 ]-octreotide (dotatoc), is well established for diagnosis [4] and therapy [5] of somatostatinpositive tumors such as neuroendocrine tumors. the cu i -catalyzed azide-alkyne addition 1 (cuaaa), the useful variant of "click chemistry," has emerged as a powerful technique for specific addition. that chemistry is also commonly used for conjugation, and cyclization of peptides. it is known that cyclization can increase the metabolic stability of peptides, as well as enhance potency or selectivity. another useful application of the cuaaa, which we are reporting, is the n-terminal crosslink of two synergic peptides to gain their potency. cuaaa reaction is performed on solid phase (merrifield resin) where one of the peptide components with azido group on the linker (6azido-hexanoic acid) is "clicked" with second peptide component in solution, made by fmoc strategy in partially protected form containing at n-terminal side alkyne group (fmoc-l-propargylglicine). cuaaa coupling is performed in dmf/t-buoh/h2o with presence of cui and sodium ascorbate when reacting mixture was degassed. linked peptides are cleaved finally from resin and purified. as an application example we picked two endothelin active peptide analogues: bq123 derivative 2 (a highly potent and selective eta antagonist) and irl-1620 derivative 3 angiogenesis is a key step in the transition of tumors from a dormant state to a malignant state. the vascular endothelial growth factor (vegf) is a major contributor to tumor angiogenesis. its pro-angiogenic activity is mainly mediated through binding to two tyrosine kinase receptors located predominantly on the surface of endothelial cells: vegfr-1 and vegfr-2. vegf binding to these receptors triggers the activation of different signal transduction pathways responsible for the proliferation, survival and migration of endothelial cells 1 . vegf/vegfr system constitutes a target to stop tumour growth. an attractive approach is the development of peptides, or small-molecules, with a high affinity for the extracellular domain of the receptors to prevent vegf binding. based on the x-ray structure of vegf and the d2 domain of vegfr-1 2 , cyclic peptides had been developed in our group 3 . such peptides, mimicking simultaneously the 3-4 loop and helix ·1 of vegf, can bind to d2 domain of vegfr-1 and inhibit receptors phosphorylation and thus map kinase pathway 4 . we describe here our strategies to optimize peptidic antagonists of vegfr-1. chemical modifications are made in order to better mimic peptide conformations and to increase their receptor binding affinities. we introduce a hydrophobic functional group at the c-terminal of the original cyclic peptide 4 , some of such modified peptides reveal improved vegfr-1 binding affinity. otherwise, as the helix ·1 presents most of the important residues in vegfr1 binding according to alanine-scan in the literature5, we try to stabilize the helical conformation by insertion of aib residues or by peptide cyclisation. the peptides affinities are evaluated by an elisa test developed previously 3 . institute of chemistry and biochemistry, freie universität berlin, thielallee 63, d-14 195 berlin, germany new polypeptide was isolated from the azemiops feae viper venom by combination of gel filtration and reversephase hplc and called azemiopsin. its amino-acid sequence (dnwwpkpphqgprpprprpkp) was determined by means of edman degradation and mass spectrometry. it consists of 21 residues and does not contain cysteine residues. according to circular dichroism measurements, this peptide adopts a β-structure. peptide synthesis was used to verify the accuracy of the determined sequence and to prepare sufficient peptide amount for biological activity studies. azemiopsin efficiently competed with α-bungarotoxin for binding to torpedo nicotinic acetylcholine receptor (nachr) (ic50 0.18±0.03 m) and with lower efficiency to human α7 nachr (ic50 22±2 μm). ala scanning showed that amino-acid residues at positions 3-6, 8-11 and 13-14 are essential for binding to torpedo nachr. in biological activity azemiopsin resembles waglerin, a specific blocker of muscle-type nachr from tropidechis wagleri venom. however the sequences of these peptides are markedly different, and azemiopsin is the first natural toxin to block nachrs that does not possess disulfide bridges. laboratory of peptide science, nagahama institute of bio-science and technology, nagahama, shiga 526-0829, japan while neutrophils infiltrate into damaged sites immediately after tissue injury, endogenous factors which induce their acute transmigration and activation have not been thoroughly elucidated. for the candidates, we recently identified two novel neutrophil-activating cryptides, mitocryptide-1 (mct-1) and -2 (mct-2), which were hidden in mitochondrial cytochrome c oxidase and cytochrome b, respectively [1] [2] [3] . in addition, the presence of many neutrophil-activating peptides other than mct-1 and -2 was observed during their purification. these findings suggest that neutrophils are regulated by many unidentified peptides. here, we purified a novel neutrophil-activating octadecapeptide whose primary structure was identical to mitochondrial cytochrome c (68-85) from porcine hearts. we named this functional peptide as mitocryptide-cyc (mct-cyc). the structure-activity relationships of cytochrome c on β-hexosaminidase release from neutrophilic differentiated hl-60 cells demonstrated that cytochrome c (70-85) was the most potent cryptide among cytochrome c-derived peptides. since cytochrome c is known to be involved in the apoptotic process, our present results suggest that cryptides produced from cytochrome c play an important role in scavenging toxic debris from apoptotic cells by neutrophils. anthracis spores are very resistant and can remain dormant in soil for decades. therefore, an effective detection system for b. anthracis is urgently needed. recently, it was found that one of the components of the b. anthracis exosporuim is a collagen like protein whose carbohydrate portion is composed of the tetrasaccharide with the highly specific monosaccharide upstream terminal, named anthrose. 1 since anthrose was not found on other bacterial spores, including those closely related to b. anthracis, this monosaccharide is an attractive target for the development of new b. anthracis detection and identification methods. peptide cyclization represents particularly interesting approach for the design of artificial receptors for anthrose, because cyclic peptides provide the possibility of having a spherical lipophilic binding site of appropriate size and shape for a particular carbohydrate substrate. 2 the presence of hydrogen donor/acceptor groups within a three-dimensional structure permits carbohydrate substrates to be encapsulated, thereby allowing their binding in water. in order to determine whether the cyclic peptide receptor can selectively detect the anthrose, we have successfully prepared cyclic peptide combinatorial library (total 6859 peptides) by the process of divide, couple and recombine ("tea-bag" technology) using standard fmoc solid-phase peptide synthesis. 3 prepared combinatorial library is screened for anthrose binding in fluorescence-based assay, and individual cyclic peptides with enhanced affinity toward anthrose are identified by the positional scanning deconvolution process. 3 cyclization of linear sequences is a well-known approach used to restrict the flexibility of peptides. cyclization often increases selectivity of peptides towards one specific receptor type, increases metabolic stability and generally increases lipophilicity, which often improves the bloodbrain barrier permeability of peptides. in our previous study [1] we have reported on the synthesis of a cyclic endomorphin-2 (em-2) analog, tyr-c(d-lys-phe-phe-asp)-nh2, which elicited analgesia after peripheral administration. encouraged by the fact that this analog was able to cross the blood-brain barrier we designed and aliskiren is the first orally active, direct renin inhibitor to be approved for the treatment of hypertension. its structure and conformational analysis were explored using molecular dynamics (md) simulations. for the first time, md calculations have also been performed for aliskiren at the receptor site, in order to reveal its molecular basis of action. it is suggested that aliskiren binds in an extended conformation and is involved in several stabilizing hydrogen bonding interactions with binding cavity (asp32/255, gly34) and other binding-cavity (arg74, ser76, tyr14) residues. of paramount importance is the finding of a loop consisting of residues around ser76 that determines the entrapping of aliskiren into the active site of renin. the details of this mechanism will be the subject of a subsequent study. additionally molecular mechanics poisson-boltzmann surface area (mm-pbsa) free energy calculations for the aliskiren-renin complex provided insight into the binding mode of aliskiren by identifying van der waals and nonpolar contribution to solvation as the main components of favorable binding interactions. adamantyltripeptides and phospholipids in liposomal bilayers 1 . now, we were primarily interested to study incorporation profile of mannosylated adamantyltripeptides. we have demonstrated that the adamantyl moiety, due to its liphophilic properties, penetrates into the lipid core of the bilayer while the hydrophilic part with the mannosyl moiety is exposed on the liposome surface. after concanavalin a (con a), a lectin, which specifically binds α-d-mannosyl residues, was added to the liposome preparation, increase in liposome size and appearance of aggregates has been observed. the enlargement of liposomes was ascribed to the specific binding of the con a to the mannose present on the surface of the prepared vesicles. the afm analysis revealed that the adamantyltripeptide molecules grouped into small domains that raise above the bilayer surface. the molecule size and molecular geometry, as well as the hydrophilic and hydrophobic surfaces in the structure of mannosylated adamantyltripeptides, are responsible for arrangement of molecules in the lipid bilayer. this approach might be a useful model for investigation of specific protein interactions with membrane receptors. also, the adamantyl moiety may be considered as a potential membrane anchor for different carbohydrate or other molecules of interest, which could be bound on it and thus exposed on liposome surfaces and as such used in targeted drug delivery. the assay is carried out in a 96 well format p122 and images are captured throughout the course of the assay, thus we can not only determine a ligand's propensity to induce internalization, but also its efficacy and internalization rate. addition of test compound, followed by the standard agonist at a later interval, enables differentiation between agonist or antagonist activities. in the positional scanning format [1] , while the possibility of agonists and antagonists working against each other within a mixture exists, the effects are minimized in screening the whole library as there are as many arrangements of the sub-libraries as there are defined positions. therefore while an agonist and antagonist might be present in a particular mixture in one sub-library they will be in different mixtures in all other sub-libraries. we have used this assay format to simultaneously screen for novel agonists and antagonists against the orexin 2 receptor. assay development and library screening will be presented. [1] . since the pro residue in position 2 of em2 is very important in the proper conformational alignment of the two aromatic residues tyr 1 and phe 3 in em2 molecule at the receptor site, it is possible that structural modification around the pro 2 residue yields compounds with unique biological properties and improved metabolic stability. in the present study, we synthesized seven em2 analogues containing isopro or constrained residues with oxopyrrolidine or oxopiperadine ring, instead of pro residue in position 2. all peptide analogues were synthesized solid phase method. incorporation of oxopyrrolidine and oxopiperadine rings were carried out on a solid support by the methods of gellerman, et al. [2] and mohamed, et al. [3] , respectively. opioid receptor binding activity for μ and δ-receptors using the development of resistance to mainstay cancer therapies has become a major limitation for the treatment of many cancers. there is an urgent need to develop new antineoplasic agents with innovative anticancer approaches. to overcome resistance to cancer therapies, our attention has turned to proteins that regulate multiple signalling pathways essential for tumour survival. among the few known nodal proteins upregulated in cancer cells and involved in many hallmarks of cancer, we are interested in survivin. an essential regulator of cell proliferation and apoptosis, survivin is sharply overexpressed in cancer cells and plays a major role in resistance. 1 being a small protein, its bioactivity is relies mainly on protein-protein interactions (ppi) with different partners. a critical point for its multiple functions in cancer is its association with hsp90, which is required for its stability. a nonapeptide from survivin called shepherdin has been shown to modulate the interaction of survivin with hsp90 by binding to hsp90 and to induce death of tumour cells. 2 unfortunately, shepherdin is not cell permeable, has low proteolytic stability and shows poor bioavailability, limiting its use as anticancer therapeutic agent. to improve pharmacological properties of shepherdin, cyclic and peptidomimetic analogs of shepherdin have been synthesized followed by structure-activity relationship studies. in hsp90 binding studies, some cyclic hexa-and heptapeptidic analogs showed increased affinity compared to shepherdin. the synthesis of cyclic and peptidomimetic analogs and the results from the binding assays and the conformational analyses will be presented. the hexapeptides with formula ac-ryyr/kw/ir/k-nh2 have been identified as shortest peptide sequence with high nop receptor affinity, selectivity and marked analgesic effect. it was found that the following peptides act as partial or full agonists or antagonists of nop receptor in different in vivo and in vitro systems. these hexapeptides were used as chemical templates in sar studies 1,2 . the aim of the present study was the synthesis and the biological screening of new analogs of ac-rfmwmk-nh2 and ac-ryyrwk-nh 2 , modified at position 4 and 5 respectively with newly synthesized β 2 -tryptophan analogues 3 . these non natural amino acids were prepared using reaction of asymmetric friedel-crafts alkylation of various indoles with a chiral nitroacrylate to provide optically active β-tryptophan derivatives. the four newly synthesized ligands for the nociceptin/orphanin fq (n/ofq) receptor (nop) have been prepared by solidphase peptide synthesis-fmoc-strategy. these compounds will be tested for agonistic activity in vitro on electrically stimulated smooth-muscle preparations isolated from vas deferens of wistar rats. bacterial infections are a common problem associated with dermal wounds. these infections can prolong or impair wound healing. hydrogel materials that display inherent activity against bacteria can be used to directly treat accessible wounds to prevent or kill existing infection. in this work, we describe the design and utilization of injectable gels prepared from self-assembling β-hairpin peptides having a high content of arginine. these gels were found to be extremely effective at killing both gram-positive and gramnegative bacteria, including multi-drug resistant p. aeruginosa. importantly, no added antibacterial agents are necessary since the nanostructure of the gel, itself, is the active agent. using self-assembling peptides for material construction allows facile structure-activity relationships to be determined since changes in peptide sequence at the monomer level are directly transposed to the bulk material's antibacterial properties. structure-activity relationships studies show that arginine content largely influences the hydrogel's antibacterial activity, and influences their bulk rheological properties. these studies culminated in an optimized gel, composed of the peptide pep6r. pep6r gels prepared at 1.5 wt % or higher concentration, demonstrate high potency against bacteria, but are cytocompatible towards mammalian mesenchymal stem cells. the general mechanism by which pep6r exerts its action was explored and it is suggested that involves membrane disruption that occurs when cells come in contact with the gel's surface. atomic force microscopy (afm) was used to study the effect of the gel on the cell envelope morphology of e. coli. rheological studies indicate that the gel is moderately stiff and displays shear-thin recovery behavior, allowing its delivery via simple syringe. 1 they are intimately involved in the molecular process leading to the delicate nano-patterned silica shells of diatoms. deciphering the mechanisms of silica-biogenesis in diatoms will inspire the development of novel routes for the biomimetic synthesis of silicon-based materials under mild conditions and expand the scope of biotechnological applications, e.g. for immobilization of enzymes in silica matrices. we synthesized silaffin peptides derived from c. fusiformis that carry posttranslational modifications such as phosphorylation or polyamines linked to lysine side chains. a distinct alteration of silica precipitation activity depending on the particular modifications of the silaffins emerged. 2 these modified silaffin peptides were covalently linked to recombinant proteins by expressed protein ligation leading to stable protein-silaffin conjugates. 3 using egfp as model protein, we could show that egfp-silaffin conjugates can induce biomineralization of silica and ensure an efficient and homogeneous immobilization of egfp into silica particles, superior to simple co-biomineralization approaches. moreover, a significant stabilization of immobilized egfp against denaturing agents was observed. we established a method for controlled immobilization of biomolecules based on covalent attachment of silaffin peptides with well-defined silica precipitation properties. currently this method is applied to the immobilization of biotechnological relevant enzymes in order to test their activity and the stabilization effect. herein, we present the covalent functionalization of multiwalled cnts (mwcnts) with organocatalysts based on proline or proline derivatives carrying either a dipeptide or a sulfonamide moiety. two different approaches were followed, namely, covalent grafting of the organocatalysts either at the tips or at the sidewalls of the cnts. for the former approach, mwcnts were oxidized in order to introduce carboxylic units at their tips and make them easily dispersed in aqueous solutions. then, oxidized mwcnts readily reacted with proline-based derivatives carrying a free amino unit yielding the corresponding hybrid materials. for the latter approach, the functionalization methodology based on in-situ generated aryl diazonium salts was followed. in this context, mwcnts were modified with aryl units carrying free amino terminal groups, which were subsequently conjugated with proline-based derivatives carrying a free carboxylic unit. all newly formed hybrid materials were fully characterized with complementary spectroscopic (atr-ir, raman), thermal (tga) and microscopy (tem) techniques. the catalytic evaluation of the activity of the cnt-based organocatalysts in aldol reactions is in progress. financial support from gsrt/εσπα 2007-2013 συνεργασια through 09συν-42-691-νανοκαταλυση project is acknowledged. novel organogels based on self assembly of rationally designed pseudopeptides c. pappas, n. sayyad, a.g. tzakos, i. plakatouras section of organic chemistry and biochemistry, department of chemistry, university of ioannina, ioannina, gr-45110, greece self-assembly is becoming a rather intriguing way to build an array of nano-and micro-structured materials. low molecular weight organogelators can self-assemble into various architectural types in organic solvents through weak intermolecular interactions. such organogelators have potential applications in the generation of novel materials for nanobiotechnology1. herein, we report the synthesis of rationally designed pseudopeptides and the conditions to form organogels. the obtained gels are responsive to temperature, and the sol-gel process is thermoreversible. the architecture of the constructed organogels was characterized via tem and spectroscopic techniques. diffusion ordered nmr spectroscopy (dosy) was further utilized to determine differences in the molecular shape of the different pseudopeptides. applications of the resulted compounds in nanotechnology will be reported. since 2000, organocatalysis has met such a great rate of expansion that is nowadays considered the third major branch of modern asymmetric catalysis along with the transition metal catalysis and biocatalysis. after the seminal work of list, lerner and barbas on the enantioselective aldol reaction between acetone and 4-nitrobenzaldehyde catalyzed by proline, it became clear that amino acids and peptides could serve as an abundant pool full of potential to develop novel organocatalytic motives. following our recent report that the combination of a prolinamide with a thiourea group having as a spacer a chiral diphenylethylenediamine leads to an efficient organocatalyst for the aldol reaction, 1 we recently considered the possibility to couple the prolinamide unit with an urea moiety. one of our main interests was the substitution of the diphenylethylenediamine spacer by a gem diamine derived from an α-amino acid. the gem diamine is easily synthesized via a curtius rearrengement of the corresponding acyl azide. after synthesis and evaluation of a number of potential catalysts, the prolinamide derivative bearing a gem diamine derived from (s)-phenylalanine and an aryl urea moiety proved to provide the best results in the reaction between cyclic ketones and aldehydes. utilizing 10 mol% of our organocatalyst, the aldol products were obtained in high to quantitative yields (up to 98%), high to excellent diastereoselectivities(up to >98:2) and high to excellent enantioselectivities (up to 99% ee). peptide self-assembled monolayers are of current interest to study physicochemical properties of modified metal (e.g. au) surfaces. rigid peptide scaffolds could enhance the interaction between gold surfaces and labels by reducing and precisely monitoring the distance between the supported monolayers and gold. the c α -tetrasubstituted αamino acid 4-amino-1,2-dithiolane-4-carboxylic acid (adt) 1 , which contains a cyclic disulfide system, is interesting in this respect because it may allow the parallel binding of the peptide helical chain to the metal surface. adt occurs in nature 2 and has been utilized in medicinal chemistry 3 and in a model compound of [fefe] hydrogenase. 4 we synthesised a series of constrained helical peptides, based on the ala-ala or the ala-aib sequence, containing one or two adt residues. these peptides were functionalised with spectroscopic or opto-electronic labels. among the large number of reactions involving the formation of carbon-carbon bond, the addition of ketones to nitroolefins is a powerful tool for the synthesis of γ-nitrocarbonyl compounds, useful intermediates for pharmaceutical industry. our recently reported primary amine-thioureas based on tert-butyl esters of natural amino acids exhibit excellent performance for the michael reaction of ketones with nitroolefins providing the products quantitatively and almost stereospecifically (>99% ee). 1, 2 using this methodology, enantiopure baclofen and phenibut (analogs of gaba) have been synthesized. 2 polymersupported organocatalysts constitute a great challenge for the michael reaction. in the current study, we report the immobilization of amine-thiourea catalysts containing (1s,2s)or (1r,2r)-diphenylethylenediamine and tert-butyl aspartate, on various polymer supports, either directly or through spacer units. the solid-supported catalysts evaluated in the reaction between acetone and βnitrostyrene and highlighted the importance of the choice of the polymer as well as the presence of the spacer or not. the direct attachment of the primary amine-thioureaaspartate to a crosslinked polystyrene-divinyl benzene resin containing a uniform distribution of aminomethyl groups provides a supported catalyst that affords the product of the reaction between acetone and β-nitrostyrene quantitatively and in high enantioselectivity (91% ee a. theodorou, g.n. papadopoulos, c.g. kokotos* laboratory of organic chemistry, department of chemistry, university of athens, athens, greece after the pioneering report that proline can catalyze efficiently the intermolecular aldol reaction between acetone and a variety of aromatic aldehydes, 1 it became evident that amino acids and peptides 2 can afford a plethora of different structural scaffolds for novel catalysts. along the first decade of its life, organocatalysis has grown to such an extend that now it is considered the third major branch of asymmetric catalysis. recently, researchers have paid special attention to other amino acids rather than proline. some primary amino acids have already been applied to a number of transformations with success. 3 usually improved catalytic properties are observed when derivatives of primary amino acids are utilised. we have undertaken a study on the application of simple and cheap primary amino acids and amino acid derivatives, either commercially available or easily obtained, as organocatalysts for the asymmetric α-amination of aldehydes. in the present work, we report that the use of simple derivatives of primary amino acids like phenylalanine and aspartic acid can efficiently catalyze this transformation leading to products in high to quantitative yields and enantioselectivities up to 94% ee. the majority of the organocatalysts developed up to now for asymmetric organic transformations employ more than one functionalities in the catalytic mechanism that act through either covalent or non-covalent interactions. for example, proline employs the pyrrolidine nitrogen and the carboxylic acid group, while chiral thioureas combine the thiourea functionality with a tertiary or a primary amino group. we have recently shown that an amide of proline with a diamine carrying a thiourea group is a very good catalyst for the enantioselective aldol reaction. 1 trying to improve the activity, we have found that a tripeptide-like thiourea having as building blocks (s)-proline, (1s,2s)diphenylethylenediamine and (s)-di-tert-butyl aspartate provides the products of the reaction between ketones and aromatic aldehydes in high to quantitative yields and high stereoselectivities (up to 99:1 dr and 99% ee). a number of structural modifications of the catalyst were undertaken in order to understand the role of the hydrogen bond donors of the catalyst, i.e. the prolinamide hydrogen and the two hydrogen atoms of the thiourea group. we have come to the conclusion that the importance of the hydrogen bond donors of the catalyst follows the order: thiourea hydrogen originated from aspartate › amide hydrogen › thiourea hydrogen originated from diphenylethylenediamine. g eldrug s.a., patras 26504, greece a convenient and facile synthesis and in vitro biological evaluation of n-substituted 5-butylimidazole derivatives as potent angiotensin ii (ang ii) receptor type 1 (at1) antagonists have been reported in the present study. a series of imidazole based compounds bearing the biphenyl moiety at the n-1 position, a halogen atom at the c-4 and polar substituents such as hydroxymethyl at the c-2 position were synthesized. 1,2 these compounds were evaluated for binding to human at1 receptor and for ang ii antagonism in vitro on isolated rat uterus. in particular, 5butyl-1-[[2΄-(2h-tetrazol-5-yl)biphenyl-4-yl]methyl]imidazole derivatives complexed with the at1 receptor and showed high binding affinity. these analogues were also found to be active in the rat uterotonic test. importantly, their binding affinities and potencies were comparable to those of losartan. these results indicate that the hydroxymethyl at the c-2 position of the imidazole ring is favorable for high affinity binding and antihypertensive activity and in line with the activities of the losartan counterparts. experimental findings are in good agreement with docking studies, which were undertaken in order to investigate ligand/at1 receptor interactions. z-leu-glu-his-asp-aluc, suc-leu-leu-val-tyr-aluc) are good substrates for bioluminescence assays, for example in the detection of caspase activity during apoptosis 1 . these substrates generally offer significant advantages, such as increased sensitivity, ease of use, and high throughput screening capacity. luciferase-based assays are typically 10-to 100-fold more sensitive than the comparable fluorescent assays (rhodamine 110, 7-amino-4-methylcoumarin (amc) and 7-amino-4trifluoromethylcoumarin (afc)). the synthesis of different type peptide-amino-luciferin conjugates and their precursors have been published 2 and some of them are commercially available. however, because of their high price the in vivo application of these conjugates is limited. to solve this problem we successfully worked out a new, easier and more convenient and economical method for the preparing these derivatives starting from 2-chloro-benzothiazole. moreover this products have excellent purity (>99%) and adequate yield (82-93%). major health problems arising from bacterial resistance towards existing antibiotics make discovery of antibacterial drugs with new mechanisms of action pertinent. although proof of concept for a novel antimicrobial approach using peptide nucleic acid (pna) antisense targeting of essential bacterial genes was obtained a decade ago, this technology is still limited by the lack of carriers that facilitate effective bacterial delivery and confer optimal pharmacokinetic properties to the prospective drugs. [1, 2] in the past two decades, parallel efforts of exploiting naturally occurring antimicrobial peptides (amps) as drugs have been made. the cationic amp subclass appears to be directly involved in the innate immune response towards microbial infections. [3] so far only few cell-penetrating peptides, with activity on mammalian cells, and other membrane-active peptides, have been investigated as potential vehicles for bacterial delivery. for instance, cationic amps with an internal target appear not to have been investigated for bacterial delivery of antibiotics. the aim of this project is to develop highly potent genetic antibiotics by exploiting naturally occurring antimicrobial peptides as potential delivery vehicles for antisense peptide nucleic acid oligomers. the amps are chosen from amps reported to act via intracellular targets, and thus must possess an inherent ability to permeate bacterial cell membranes without direct killing of the bacteria. faculty of chemistry university of gdansk, gdansk, poland azt (3'-azido-2'3'-dideoksythymidine), a modified nucleoside used in antiretroviral therapy and peptide plant hormone -systemin were used as substrates of 1,3-dipolar cycloaddition (click chemistry). systemin is 18-aa peptide defense hormone released in response to plant (tomato, tobacco) damage or pathogen attack. we examinated whether systemin's fast movement through plant tissues could be used for cargo (azt) transport. the huisgen cycloaddition also known as 1,3-dipolar cycloaddition is a chemical reaction belonging to the larger class of cycloadditions. reaction between organic azide and alkyne appended substrates allows the synthesis of the desired conjugate in high purity and yields irrespective of the sequences and functional groups on either of the two substrates [1, 2] . conjugate of azt-systemin has been synthesized by click chemistry, using systemin modified at n-terminus with propiolic group and azt. the conjugation was catalyzed by cu(i). the reaction was fast, efficient and regioselective. its progress was easily monitored by capillary electrophoresis (ce). ce was also applied for characterization of systemin and azt-systemin stability and movement throughout tomato leaf and stem. despite the fact that systemin moves rapidly through tomato tissues, our calorimetric (itc) studies showed that the peptide does not interact with liposomes-cell membrane model. universitätsklinik für nuklearmedizin, inselspital, bern, switzerland regulatory peptides (e.g., somatostatin, bombesin) have been shown to be suitable vectors for the specific delivery of radioactivity to tumors for diagnostic and therapeutic applications in nuclear oncology. 1 a potential drawback of such vectors is their inherent instability in vivo. thus, new strategies are needed for the stabilisation of radiopeptides in order to improve their bioavailability and, consequently, increase their accumulation in the targeted tissue. it has been suggested that 1,2,3-triazoles, readily obtained by cuaac, are suitable amide bond surrogates which are resistant to proteases. 2 in the present study, we report the synthesis and pharmacological evaluation of radiolabelled, triazole-containing analogues of the gastrin releasing peptide receptor (grpr) targeting peptide bombesin (bbn). to study the effect of backbone modifications in the minimal grp-binding sequence, we synthesized a series of analogues of [nle 14 ]bbn (7) (8) (9) (10) (11) (12) (13) (14) , in which each amide bond is individually replaced by a 1,4-disubstituted 1,2,3triazole. after radiolabelling of the peptidomimetics, their binding affinity and internalization kinetics were determined using pc-3 cells. metabolic stability was evaluated in blood serum. a number of the novel tumor-targeting peptide analogues presented exhibit both a retained high affinity (nm) towards the grpr and an improved serum stability. first preclinical data on the in vivo evaluation of the most promising candidate will be presented. to the best of our knowledge, this is the first report of the systematic replacement of amide bonds with 1,2,3triazoles within the binding sequence of linear, high affinity peptides. the methodology can be applied to a variety of peptide vectors and thus, holds great potential for the development of novel, stabilized peptide-based radiopharmaceuticals. dna is the molecular target for many of the drugs that are used in cancer therapeutics, and is viewed as a nonspecific target of cytotoxic agents. although this is true for chemotherapeutics, other agents that were discovered more recently have shown enhanced specificity. 1 the development of new site-specific dna binders, which are associated with the recognition of the dna major groove, are based on the design of transcription factor mimics that bind the dna as a dimer 2 , and prevent specific genes from being transcribed. these could ultimately result in interesting biomedical applications as designed genome interfering agents or diagnostics. 3 in order to approach this biological constructs, we choose the bzip leucine zipper transcription factor as a model to mimic. as the entire structure cannot be synthesized without expensive, complicated and time-consuming biotechnological methods, the substitution of the dimerization domain by a less complex scaffold is the first step in the design. thus, we consider a steroid based scaffold as a candidate. the specific choice of the steroid scaffold as substituent is inspired by its known ability to enhance proteolytic stability of attached peptides, by its conformational properties ensuring correct positioning of the two appended chains and by its potential to increase bioavailability. this transcription factor binds specific dna sequences by dimerization and inserting short α-helices into the dna major groove. in order to attach the peptides to the scaffold, different strategies were studied. firstly, applying the well-known click chemistry, functionalizing the scaffold with an alkyne moiety, the peptide with an azide and viceversa. secondly, via the unknown resin to resin transfer reaction (rrtr), which has not been applied on peptide chemistry so far. this unprecedent methodology consists on the reaction of a peptide, which is attached on a safety-catch resin, with a second resin bearing a nucleophilic amino terminus resulting in amide bond formation. during the process, the peptide on solid support undergoes cleavage. an hexapeptide was synthesized on a preloaded safetycatch resin. deoxycholic acid derived scaffold with orthogonally protected amines was attached to tentagel resin that acts as acceptor resin. rrtr experiments were performed at both c12 and c3 positions of the deoxycholic acid derivative. in addition, this convergent strategy can be applied to other different peptide conjugated systems. we recently described a new kind of cyclized peptide in which the cyclization is performed between the side-chains of two diaminoacyl residues via a diversely substituted guanidine bridge. 1 we showed that the degree of bridge substitution could impact on the orientation of the bridge inside the cycle and therefore the peptide conformation. we prepared two series (22 and 15 atoms cycle size) of cyclic enkephalin analogues to assess the potential effect of this kind of bridge on the biological activity. the compounds were synthesized on the solid support via the formation of a thiourea bridge and with the variable substituent being introduced at the last step before cleavage. it is noteworthy that the synthesis afforded at least two stable and separable conformers for each analogue of the shortest cycle series. generally, one major and one minor species were recovered. but in the case of di-substituted compounds with a cyclic moiety (pyrrolidine or piperidine substituents), three significant species were obtained. analogues were submitted to various biological assays (binding to μ and δ opioid receptors and functional assays). we observed a significant variation in affinity and selectivity for the receptors as a function of the degree of bridge substitution. a structural analysis by 2d nmr has been undertaken and correlated the variation in activity with a variation in conformation. the origin of the multiple conformers observed for the analogue with a pyrrolidine susbtituent was also investigated. this kind of cyclization could represent a useful tool to easily modulate the conformation and biological activity of a unique peptide sequence. the t-cell response is triggered by the formation of the trimolecular complex between the major histocompatibility complex (mhc), the immunodominant myelin protein epitopes and the t cell receptor (tcr). herein, we report the design and synthesis of non-peptide analogues with the ability to mimic the immunodominant epitope 83-99 of mbp 1,2 . the mimetics were designed to block the formation of the trimolecular complex and therefore the t-cell activation 3, 4 . more specifically, indole analogues were synthesized with substitution at positions 2 and 4 or 6. these molecules contain a carboxyl or an ethyl ester group in position 2 and a benzylamino or phenylamino group in position 4 or 6. the synthesis of the indole ring was achieved by fischer reaction followed by catalytic hydrogenation, reductive amination or arylation and ester hydrolysis. the synthesized molecules were purified using liquid chromatography, and they were identified by mass spectrometry and 1h-nmr. laboratory of peptide science, nagahama institute of bio-science and technology, nagahama, japan amyloid β peptide (aβ), the main component of senile plaques in the brain of alzheimer's disease (ad) patients, is formed by proteolysis of amyloid precursor protein (app). as β-secretase (bace1: β-site app cleaving enzyme 1) triggers aβ formation by cleavage at the aβ domain nterminus, it is a molecular target for ad therapeutic intervention. 1 previously, we reported potent pentapeptidic 2 and non-peptidic 3 bace1 inhibitors containing a substrate transition-state mimic. although these inhibitors exhibited potent inhibitory activities, their molecular-sizes appeared a little too big (mw>600) for developing practical drugs. in this study, we designed a series of small molecular peptides, with bace1 inhibitory activity, lacking the p1-p1' region on the basis of the conformational structure bound in bace1. 4 design and synthesis of new 3'-peptidyl-trna analogues, in particular "hydrolysable" analogues, which represent covalent conjugates of peptide-nucleic acid (pna) with "stop-peptides," were carried out. such compounds are of interest as tools to study the ribosome functioning and as inhibitors of protein biosynthesis. (2 aminoethyl)glycine pna models 3'-end trna sequence cca in designed structures. computer simulations showed the formation of watson-crick pairing of the pna cytosine residues with 23s rrna nucleotides g2251 and g2252 involved in interactions with peptidyl-trna during its specific binding in p site of the ribosomal peptidyl transferase center (ptc). short "stop-peptides" were planned for conjugation with pna. these peptides form stable complexes with the ribosomal tunnel (rt) that leads to ribosome stalling and translational arrest. structures of "hydrolysable" 3'peptidyl-trna analogues that could form peptide bond with amino acid residue of aminoacyl-trna in a-site of ptc included 2'-deoxyriboadenosine instead of the pna adenine containing residue. such conjugates would permit to identify the chemical nature of specific sites localized in rt and responsible for interactions with amino acid residues of the nascent polypeptide chain. pna and "stop-peptide" as well as pna-"stop-peptide" conjugates were prepared by solid phase synthesis on sasrin polymer using fmoc/bhoc(boc) strategy. synthesis of "hydrolysable" conjugates included modification of the 3'hydroxyl of 5'-protected 2'-deoxyadenosine by n-blocked "stop-peptide", deprotection of the 5'-hydroxyl, its conjugation with n-protected pna and removal of protecting groups from the resulted conjugate. the binding of the new 3'-peptidyl-trna analogues with ribosome will be tested by chemical probing and in the cell free translation system. this study was supported by the russian foundation for basic researches (grant 10-04-01187-a). a close structural similarity of endomorphin-2 and another atypical opioid peptide, morphiceptin, which both have a phe residue in the third position, encouraged us to study antinociceptive activity of these two peptides and their analogues. in order to improve the affinity and chemical stability of these opioid peptides, we have designed, synthesized, and analyzed 9 novel analogues. the first modification included endomorphin-2 and morphiceptin analogues, where halogenated phenylalanines in position 3 or 4 were incorporated as surrogates of the native phenylalanine. another important modifying element is non-protein amino acid canavanine (cav) and its analogue (sarg). it is well documented that cav and sarg exhibit strong analgesic activity. two new morphiceptin analogues were synthesized by introducing cav and sarg in position 3. we further characterized their antinociceptive activities by the paw pressure (pp) test. the experiments were carried out on male wistar rats (180-200 g), treated with i.p. doses of 1 mg/kg. e eldrug s.a., patras 26504, greece the renin angiotensin system (ras) has been a prime target for the therapy of cardiovascular diseases. angiotensin ii type 1 (at1) receptor mediates vast majority of biologically detrimental actions. non-peptide at1 receptor blockers are presently the most specific means to block the ras enzymatic cascade. the dupont group was the first to develop losartan (dup 753), an orally effective angiotensin ii receptor blocker, which is metabolized in vivo to the more potent antagonist exp 3174. herein, we report on the preparation of e-urocanic1 acid based analogs, focusing our attention on the introduction and structural modifications of the substituents on the imidazole ring as well as the modifications on the acrylic side chain. in particular, we have designed and synthesized a series of urocanic acid analogs bearing the biphenylmethyl tetrazole moiety at the n-1 of the imidazole ring.2 additionally, the rigid acrylic chain was lengthened by esterification resulting in the ethyl ester and on the other hand the latter was readily converted to the corresponding acrylic alcohol or aldehyde which may proved to be effective structural elements for enhancing biological activity. finally, a lipophilic alkyl chain such as the n-butyl group was introduced at the 2-position of the ring which may possibly enhance the antihypertensive activity. docking studies and biological evaluation of the synthesized analogs are being undertaken. university of athens, department of chemistry, laboratory of organic chemistry, 15701, panepistimiopolis zografou, athens, greece the backbone modification of bioactive peptides with replacement of a scissile peptide bond in enzymatic hydrolysis is a well-established strategy for developing protease inhibitors. 1 in particular, for zinc metalloproteases, which contain a zinc atom in their active site, several successful modifications have been reported over the past years. 2 phosphinic pseudopeptides are among the best candidates when addressing the challenge to potent and selectively inhibit zinc proteases. a thorough search in the literature3 revealed the absence of any reference regarding thiophosphinic pseudopeptides. we thought that this class of compounds would add a valuable tool in the field of zincbinding groups. in the present study, we describe in detail the first synthesis of a new class of phosphorous compounds, thiophosphinyl dipeptide isosters (tdis). we prepared several fully protected thiophosphinate pseudodipeptides of the general formula pg-phe-ψ[p(s)(ox)ch2]-gly-pg' starting from the corresponding phosphinate pseudodipeptide using lawesson's reagent. selective deprotection of these compounds was also studied and the results are disclosed. these compounds can be used as building blocks for the synthesis of longer thiophosphinic pseudopeptides after suitable deprotection and elongation as well as transition transition state-mimicking inhibitors for several zinc metalloproteases. in the last decade, trypsin inhibitor sfti-1 isolated from sunflower seeds [1] has become one of the most studied peptidic inhibitors of serine proteases. owing to its small size and a strong trypsin inhibitory activity (ka = 1.1×10 10 m -1 ), sfti-1 is considered to be a very attractive template for designing proteinase inhibitors with the potential use as pharmacological agents [2] . it could also serve as an affinity probe for the isolation of trypsin like (sfti-1) or chymotrypsin like ([phe5]sfti-1) proteinases. following this idea, we decided to synthesize a set of cell-permeable monocyclic sfti-1 analogues with a fluorophore moiety attached at their n-termini. the presence of the fluorophore in the molecule enabled us to show that the analogues can cross the cell membrane. the cell penetration assay was performed using multiple cell lines (hela cells and human fibroblasts cell line (46br.1n) was obtained from european collection of cell cultures (ecacc)). for all the obtained peptidomimetics, we determined the association constants with cognate proteinases. selected peptides were also used as a probes for the detection of inhibitor -proteinase complex, which was achieved by the means of gel filtration chromatography equipped with fluorescence detector and acrylamide native gel electrophoresis. the functional reconstruction of folded protein surfaces with peptide-based mimics is an enormous scientific challenge. the majority of proteins show activity through a small area of their folded surface: "the binding site". however, linear peptides are too flexible and seldomly adopt the correct 3d-structure of the binding site spontaneously. therefore, they show limited or no activity at all 1 . crucial for activity is to control the secondary (αhelix, β-sheet and/or β-turn) and tertiary structure (relative orientation of subdomain structures). we present the development of a new type of watersoluble scaffolds that have the potential to control both secondary and tertiary structure of discontinuous (i.e. double-loop) protein mimics. the new scaffolds contain a first pair of reactive functionalities to constrain the linear peptide conformation via a 'clips' reaction2, stabilizing the secondary structure. next to this, a second functionality allows for ligation of two dissimilar constrained peptides to form a discontinuous binding site mimic via oxime-ligation or click-reaction. these ligations offer the ability to position different peptide loops in 3d, thus mimicking the tertiary structure of the native protein. most unique to our approach is the fact that all chemical conversions are performed in aqueous media, using side-chain unprotected peptides 3 . growth hormone-releasing peptide 6 (ghrp-6) is a synthetic hexapeptide (his-d-trp-ala-trp-d-phe-lys-nh2), which interacts with two kinds of receptors: growth hormone secretagogue receptor 1a (ghs-r1a) and cluster of differentiation 36 (cd36). the latter is a membrane glycoprotein member of the class b scavenger family, and decreases the internalization of oxidized lipids into macrophages, as well as causes inhibitory effects on angiogenesis associated with binding to thrombospondin. to increase activity and selectivity for the cd36 receptor, different analogues of ghrp-6 were synthesized. in particular, substitution of trp 4 in ghrp-6 by aza-amino acids has given selective analogs, due likely to induction of a β-turn secondary structure. for aza-peptide synthesis, a submonomer solid-phase approach has proven effective to introduce side chains onto the semicarbazide residue. studying influences of benzylidene, benzhydrylidene and fluorenylidene residues during the alkylation of the semicarbazide, superior conversion was observed with fluorenone derivative, and mild alkylation conditions employing et4noh as base have improved yields and minimized racemisation. our presentation will focus on the improved submonomer synthesis method for optimization of selective and potent cd-36 ligands with antiatherosclorotic and anti-angiogenic effects. for instance, the integrin αvβ3, vitronectin receptor, is expressed in a number of cell types and has been shown to mediate adhesion of osteoclasts to bone matrix, vascular smooth muscle cell migration, and angiogenesis. integrin αvβ3 also play a significant role in tumor growth, invasion and metastasis, and is a receptor for the extracellular matrix proteins with the exposed arginine-glycine-aspartic (rgd) tripeptide sequence. rgd has been shown to be potent antagonist of the integrin αvβ3, and has excellent anti-angiogenic properties including its suppression of tumor growth in animal models. in this context, drug design based on the rgd structure may provide new treatments for diseases such as thrombosis, osteoporosis, and cancer. we designed and synthesized series of short rgdmimetics containing the sequence xaa-gd, where xaa is arg-mimetic. as promising candidates we have chosen canavanine (cav) and canaline (can) instead of the basic residue arg. in order to improve antitumor activity of the parent molecule, c-terminal modifications were also applied. their cellular uptake was determined on human breast (mcf7) cancer cell lines. furthermore, the in vitro cytostatic effect was evaluated by mtt assay on human liver hepatocellular carcinoma (hepg2) and human breast (mcf7) cancer cell lines after 24, 48 and 72 hours of treatment. in the case with the human tumor cell lines (hepg2, mcf7) and c-modified analogues, statistically reliable results were achieved for the most of concentrations used. acknowledgements: this work was supported by bulgarian ministry of education and science, project my-fs-13/07. microwave assisted solid phase synthesis of urea and urea/amide based foldamers k. pulka, c. douat-casassus, g. guichard* european institute of chemistry and biology, university of bordeaux 1 -cnrs umr 5248, pessac, france foldamers 1 are fully arti cial molecules that structurally and functionally mimic variety of biopolymers. among them, aliphatic n,n'-linked oligoureas with proteinaceous side chains can adopt extremely robust helical folds stabilized by intramolecular three-centred h-bonds. 2 owing to their resistance to enzymatic degradation, diversity of side chains and structural predictability urea-based foldamers represent unique scaffolds to elaborate functional mimetics of α-polypeptides. of note, heterogenous oligo(urea/γamides) backbones obtained by substituting nh groups by ch2 display very similar folding propensities. in our laboratory we are investigating the solid phase synthesis of urea and urea/γ-amide oligomers. urea bonds are incorporated into the growing chain by reaction of active succinimidyl carbamates. previously we have applied two different strategies involving fmoc-or bocchemistry, but both methodologies suffer some limitations. 3 therefore a new strategy (compatible with the use of tfa sensitive linkers and side chain protecting groups) featuring azide as a masked amine group has been developed. the synthesis of 15 new azido protected succinimidyl carbamate building blocks is reported. they were obtained in 6 steps from α-amino acids (12-45% overall yield). the staudinger reduction with pme3 was successfully applied to restore the amine group after urea formation on solid support. in addition, microwave irradiation has been found to dramatically accelerate the synthesis. overall, this azide-strategy combined with microwave irradiation was found to be very effective for the solid phase synthesis of oligoureas and related hybrids, surpassing previously developed approach utilizing fmoc chemistry. these antibiotics should have a mechanism different from currently used antibiotics to circumvent existing resistance mechanisms 1 . previous results have shown that "genetic" antibiotics operating by gene silencing in bacteria via rna interference may be successful new candidates. efficient silencing requires efficient crossing of cell membrane. this step can be alleviated using cell penetrating peptides (cpp) as carrier of drug candidates, such as peptide nucleic acids (pnas) which inherently have poor internalization properties 2 . the aim of this study is to elucidate mechanisms of uptake in bacteria using pna-cpp conjugates, which previously have shown promising antibacterial effects 2 . the fate of the pna and cpp parts of the conjugates, once inside the cell, is investigated regarding localization and possible degradation within the cell. furthermore, a method for toxicity testing of pna-cpps is being developed using histamine release in rbl-2h3 cells as a quantitative measure of allergenicity of pna-cpps. the prospect of this information is to define boundaries within which cpps can be found, thereby rationally designing novel efficient antibacterial biomolecular drug delivery systems. oxytocin and its fragments have the potential to influence behavioral and cognitive functions, including their disturbances in some brain disorders. therefore, there is an interest to synthesize new peptide-steroids chimeras for potential therapeutic use. oxytocin analogue was synthesized in solution by coupling azido-phenylalanyl residue or p-azidopegylated handle to the n-terminal end of oxytocin molecule. its c-terminal fragment pro-leu-gly-nh2 (mif-1) was elongated at proline residue by the same type of azido handles as well. both peptides were marked for fluorescent detection of their possible binding on brain slices. peptide chimeras with the suitable steroids were prepared via azide click to the triple bond on the modified steroid counterpart like (17α)-17-hydroxypregn-4-en-20-yn-3-one, 24-norchol-5-en-22-yn-3β-ol. steroidyl-peptides were then used in the trials using rat-brain slices. the sites of the peptide-steroids chimeras bound to the brain tissue were identified with the aid of fluorescent microscopy. the suitable chimeras will be tested for their penetration through blood brain barrier for the pharmacological effects. indicating that the orientation of the n-butyl group is of primary importance. docking studies revealed that the highly active analog affords an additional hydrophobic binding feature compared to losartan which fits to an extra hydrophobic cavity. these results may contribute to the discovery of new biologically active molecules by a convenient and cost effective synthetic strategy. the context of pain research, the co-administration of opioid agonists and nk1 antagonists previously led to an enhanced antinociceptive potency, 1 and recently largent-milnes and co-workers have shown that a hybrid opioid-nk1 octapeptide was able to attenuate tolerance development, related to sustained opioid treatment. 2 our group has prepared a compact opioid agonist-nk1 antagonist peptidomimetic chimera dmt-d-arg-aba-gly-nme-3',5'-bn(cf3)2 1 that served as a lead structure. 3 we report a solid phase method for the synthesis of the 4amino-1,2,4,5-tetrahydro-2-benzazepin-3-one (aba) structure, which is used as a central unit in the investigated dual ligands. this method allowed the rapid assembly of new bifunctional ligands containing the aba structure. variations of the d-arg 2 , gly 4 and n-benzyl substituents were made. the introduction of d-cit 2 , a gly 4 → β-ala4 substitution and the removal of the trifluoromethyl substituents in 1 caused considerable shifts in receptor binding. the obtained structure-activity relationships will be presented. hence, a promising approach for the treatment of dmd is the use of drugs to force ptc readthrough. (+)-negamycin 1 is a dipeptidic antibiotic containing a hydrazide structure. although (+)-1 was not clinically developed due to some toxicity, it was recently reported that (+)-1 restore dystrophin expression in the muscles of mdx mice, an animal model of dmd. 1 therefore, (+)-1 is a promising therapeutic candidate for diseases caused by nonsense mutations. based on our own efficient total synthetic method of (+)-1, 2 structure-activity relationship (sar) study was perfromed to discover derivatives with a potent readthrough-promoting activity. we found a derivative, (5r)-5-hydroxy-6-aminohexanoyl-glycine exhibited not antimicrobial activity but a similar readthrough activity to (+)-1, suggesting that the ptc readthrough mechanism can be distinguished from the antimicrobial mechanism. 3 moreover, we synthesized 5-epi-negamycin and found that this analog exhibited a similar activity to (+)-1 in in vitro readthrough assay. this result hence prompted us to synthesize a 5-dehydro-derivative, e.g., 5-dehydro-3-epinegamycin 2, which is a natural product with little antimicrobial activity. surprisingly, we found that 2 showed a higher in vitro readthrough-promoting activity than (+)-1. this result suggests that mother nature independently evolved readthrough-promoting products like suppressor trna, in distinction from aminoglycosides, which show both antimicrobial and readthrough-promoting activities. agricultural university of athens, athens, greece high interest has been paid to synthetic structural motifs that promote specific conformations because of their importance for the development of new therapeutic peptidomimetics. 1 in addition, such motifs may show catalytic activity for asymmetric organic transformations. during the last two decades, various synthetic structural motifs that promote reverse turns have been studied. following our interest on chiral prolinamide-thioureas that present interesting organocatalytic activity, 2 we have undertaken a combined experimental/computational study to understand the structural features that may stabilize a reverse turn in short-length peptidomimetics containing a thiourea functionality. compounds with the sequence r-pro-diphenylethylenediamine-thiourea-asp(obut)-obut (r: boc or fmoc, or boc-ala), were synthesized and studied by nmr spectroscopy (tocsy, 1h-13 c hsqc, noesy, roesy spectra) for the sequential assignment and the exploration of the dipolar connectivities. sampling of the conformational space was driven by the noe intensities while molecular dynamics simulations were further applied to the consistent with the experimental data conformers in order to monitor the stability of the formed hydrogen bonding interactions in the course of time. energy refined produced conformers were subsequently modified by applying all combinations of d-and l-amino acids at each site in a stepwise manner. the modelled structures were studied in silico aiming to explore the combinations of heterochiral residues which would promote a folded structure and would favour the potential of β and γ turn motif. the most promising combinations were chosen for synthesis and subsequent nmr characterization. 3 in this research project we will deal with chemical strategies to produce suitable surface modifications in order to induce multidirectional cellular migration along gold surfaces. to achieve this objective we want to use and characterize self-assembled monolayers (sams) of thiolated dna chains (dna-sh) adsorbed on gold surfaces through the hybridization with complementary modified single-stranded pnas. pna is a structural dna mimic obtained by polymerization of n-(2aminoethyl) glycine monomers that replace the ribose-phosphate backbone characteristic of natural nucleic acids. it is an achiral, uncharged, and relatively rigid biopolymer of high biological and chemical stability, 4 and it can bind complementary dna strands with higher affinity than the corresponding dna sequences.for all these reasons we have chosen pna as a key molecule to promote and assist the movement of cells. by producing a chemical gradient of dna-sh along a gold surface in the presence of a chemotactic molecule it will be possible to obtain and control a directed cellular migration. the norwegian structural biology centre and the centre for theoretical and computational chemistry, department of chemistry, university of tromso, 9037 troms , norway renin is a highly selective aspartic protease which catalyzes the hydrolysis angiotensinogen, a protein secreted from the liver, to the decapeptide angiotensin-i. 1 angiotensin-i is further processed by the relatively nonspecific angiotensin converting enzyme (ace) to give the octapeptide angiotensin-ii, a potent vasoconstrictor and the dominant peptide produced by the reninangiotensin system. renin catalyses the rate determining step in the formation of angiotensin-ii, and has for several decades been an established therapeutic target for drug development in relation to hypertension. 1 in the search for renin inhibitors, substituted piperidine derivatives have been identified as promising, 2-4 and piperidines have proven to be efficient scaffolds for the development of novel non-peptide aspartic protease inhibitors, particularly towards renin. [5] [6] [7] we herein describe a series of 4-triazolyl substituted piperidine derivatives that have been synthesized from n-boc protected trans-4-ethynyl-3-hydroxy piperidine and tested as novel renin inhibitors. piperidine derivatives containing a 1-substituted 1,2,3-triazol-5-yl substituent were found to be most active and molecular docking experiments provides a rank order that is in very good agreement with experimental data. the cxcr4/sdf-1 axis is involved in many biological processes such as hematopoiesis, immune cell migration, as well as in cancer metastasis. cxcr4 also mediates the infection of t-cells with x4-tropic hiv functioning as a coreceptor for the viral envelope protein gp120. cxcr4, as a pharmaceutical target, is of utmost importance but the lack of synthetic agonists has seriously slowed down drug development. it has been recently described by our research group 1 , that grafting the sdf-1 n-terminus onto a side-chain of the inverse agonist t140 2 . generated high affinity synthetic agonists as well as partial agonists for the chemokine receptor cxcr4. to remain stable towards proteases and act as useful pharmaceutical tools, the pk-adme properties need to be improved with a gradual transition to peptidomimetic structures. medicinal chemistry witnessed major advances with the discovery of small synthetic molecules that mimic the natural peptidic substrates. these small molecules do not undergo proteolytic degradation, an advantage they hold over natural counterparts. in order to improve stability against proteases, part of the sdf-1 chain was replaced with variable lengths of polyethylene glycol and unnatural amino acids at differents positions. here, we have produced a series of compounds, most of which showing nanomolar affinities for cxcr4 and some are displaying partial agonistic properties. tlrs are the innate immunity receptors that recognize the epitopes found on surfaces of various cells and therefore they initiate and sustain the atherogenic inflammatory response [1, 2] . we assume that the use of small stat1 mrna−binding pna−inhibitors to manipulate the activity and expression of stat1 could prove an attractive therapeutic strategy in treatment of atherosclerosis. to that end we synthesized a specific stat1 mrna−binding pna inhibitor as well as a non-specific pna to compare their inhibition of gene expression. in our work we developed effective method of synthesis of pna−peptides conjugates by means of "click chemistry". determination of optimal conditions for conjugation (connection of pna with the peptide) will allow for the design of compounds useful in gene therapy. the specificity of pna hybridization to complementary dna fragment was verified by capillary electrophoresis (ce). as an artificially synthesized somatostatin analogue, tyr 3octreotate (toca) can specifically bind to somatostatin receptor (sstr), which are usually over-expressed on many tumor cells. carbohydration of n-terminus of toca has resulted in improved pharmacokinetics and tumor targeting (1) . 18 f is an ideal nuclide for positron emission tomography (pet) imaging; there may be significant uses of 18 f labeled glucitol-toca and its analogues as tumor probes for the diagnosis of sstr-positive tumors. in order to explore a novel pet probe for diagnosis of sstrpositive tumors, we designed a synthetic route to synthesize n-gluc-lys(nota)-toca, which uses 1,4,7-triazacyclononane-1,4,7-triacetic acid (nota) as the chelating reagent. n-gluc-lys([al 18 f]nota)-toca is radiosynthesized quickly and efficiently using the chelation reaction of al 18 f complex and n-gluc-lys(nota)-toca. the aim of this study is to develop an efficient method for the synthesis of monomers of triazolic nucleic acid (tna), a new class of artificial nucleic acids. but-2-yne-1,4-diol and nucleobases derivatives will be substrates of the monomers synthesis. tna oligomers could be used as specific inhibitor of tar rna hiv-1, the regulatory rna structure crucial for hiv replication. "click chemistry" based on 1,3-dipolar cycloaddition will be used to conjugate an alkyne and azide derivatives of monomers subunits. a ru (ii) complex will be used as a catalyst of internal alkyne (but-2-yn-based) cycloaddition. the reaction gives exclusively of 1,4,5-trisubstituted derivative of triazole ring 1 . the monomers will be characterized using rp hplc, capillary electrophoresis (ce) and 1 h and 13 c nmr. the resulting monomers containing fmoc-protected amino group and a free carboxyl group will be used for the classical spps method to synthesize tna oligomers. tna sequences will be designed against tar's bulge and an external loop. 1 through the recognition that the repertoire of polypeptide conformations can be greatly expanded by the creation of structures incorporating β-amino acids. 2 moreover, the numerous advantages of hybrid (mixed α-and β-) backbone peptidomimetics with respect to homogeneous ones were quite recently outlined. 3 we describe here various β-amino acid-based β-hphe-β-hphe dipeptide derivatives, also conformationally constrained, and their application to the synthesis and biological evaluation of hybrid analogues of the opioid endogenous peptide endomorphin-2 (em-2). the opioid system mediates a wide variety of pharmacological and physiological processes, including pain perception and modulation. the amidated tetrapeptide em-2 has been shown to be μ-opioid receptor (mor) agonist exhibiting a very high μ-receptor affinity and selectivity, and it is an important model in the search towards new analgesics. 4 structural investigation of em-2 reveals the high conformational freedom of the phe side chains and also the inherent flexibility of the peptide backbone, indicating many probable bioactive conformations, ranging from βturns to extended conformations. with the aim of better clarify the relevant role of the proper spatial orientation of the aromatic rings and in particular of the benzyl side chains at position 3 and 4, 1 h nmr studies, molecular modelling, and molecular docking to a homology mor model of our hybrid analogues are currently under way. the lantibiotics represent a class of antimicrobial peptides, in which the unusual amino acids dehydroalanine and dehydrobutyrine and the intramolecular thioether bridges (lanthionines) are important structural features for bioactivity.the lipid ii -nisin complex is responsible for pore-formation since the c-terminal part of nisin is inserted into the bacterial cell membrane which ultimately results in cell leakage and collapse of vital ion gradients. in order to increase the metabolic stability of nisin, the oxidationsensitive thioether bridges can be replaced by metabolically stable dicarba moieties, as successfully demonstrated by the synthesis of nisin ab(c) analogs containing alkane/alkene bridges [1] . to obtain more insight into the importance of the cross-bridged de-ring structure (i→i+3, i+2→i+5 connectivity) on nisin's bioactivity, we synthesized a series of all four diastereomers of the crossed alkene-bridged de-ring mimic, using ring-closing metathesis. all four diastereoisomers were obtained by hplc and structurally characterized by nmr spectroscopy. an orthogonal protection scheme was used, to enable the independent n-or c-terminal modification of the bicyclic hexapeptides with azide/alkyne functionalities. via cu(i)-catalyzed cycloaddition chemistries, alkyne-functionalized natural abc-fragments of nisin, which were obtained by tryptic digestion of full length nisin followed by hplc purification, have been conjugated to synthetic de-ring mimics to obtain novel nisin derivatives and their affinity toward lipid ii and pore-forming capacity have been studied. herein, we report on the details of the synthesis and characterization of the geometric isomers of the synthetic de-ring mimics, and their use as synthons in cu(i)-catalyzed click chemistry to obtain newly designed nisin hybrids as potential novel peptide antibiotics. università di ferrara, dipartimento di biochimica e biologia molecolare, ferrara, italy mirnas play an important role in regulation of gene expression, being involved in numerous processes such as cell proliferation, cell differentiation, apoptosis and also in the progress of diseases as cancer and cardiovascular disorders. mirnas associated to diseases recently become targets for the development of new drugs based on antisense oligonucleotides or analogues complementary to the chosen mirna, in order inhibit the binding of the mirna to its mrna target. therapeutic silencing of mirna has been also observed in several animal disease model. 1 in this work we propose a new approach to interfere in the mirna function, based on peptide nucleic acid (pna) oligomers designed to be complementary to selected regions of the mirna precursor (pre-mirna). as the pre-mirna bases belonging to the stem are not perfectly complementary, we hypothesized that the mismatched duplex of the pre-mirna could be opened by pnas inhibiting of its maturation into mirna. two pna sequences, targeting respectively the "sense region" and the " 5' end region" of the pre-mir210 were designed. pnas were conjugated to different carrier peptides, hiv-tat, r8, k4 and two nuclear localization signal (nls and binls), in order to increase their cellular uptake. to verify the ability of the designed pnas to give strand invasion on the pre-mirna, we conjugated also pnas to the thiazole orange, a probe which lights-up upon hybridization 2 the development of privileged molecular scaffolds efficiently mimicking reverse turn motifs has attracted remarkable interest when structural constraints are exploited to increase both binding and selectivity of model peptides. one of the successful approaches to restrict peptide conformation is the disubstitution in the α position of an α-amino acid, leading to a conformational constraint and a stereochemically stable quaternary carbon center. in particular, spirocyclic scaffolds are able to provide, upon the attachment of appropriate functional groups, useful high-affinity ligands, relevant to the field of drug discovery. 1 at present, we are interested to spirocyclic tryptophan (trp) analogues, in order to develop new reverse turn nucleating moieties able to be inserted into pharmacologically relevant peptidomimetic compounds. among peptides sharing a tryptophan-containing β-turn motif of which the trp residue is critical for binding, we looked at the hormone peptide somatostatin, 2 acting in various organ systems as a neuromodulator and a neurotransmitter, as well as a potent inhibitor of various secretory processes and cell proliferation. 3 somatostatin and its analogue octreotide (sandostatin® drug, clinically used for the treatment of endocrine tumors and acromegaly) are thought to interact with the sst1-5 receptors mainly by inserting a β-turn substructure, carrying a lysine (lys) and a trp side chain into a pocket of the g protein-coupled somatostatin receptor. we report here the preparation and structural characterization of a new 1,2,3,4-tetrahydro-β-carboline (thbc)-based spirocyclic lactam as type-ii β-turn model compound and the application of its core structure to the synthesis of a somatostatin mimetic, whose biological evaluation is under way. the analogues of sfti-1 modified in the p 1 position by, βand γ-amino acids and n-substituted β-alanines r. lukajtis, a m. filipowicz, a a. legowska, a d. debowski, a a. lesner, a k. rolka a a faculty of chemistry, university of gdansk, 80-952 gdansk, poland serine proteinases play very important roles in many physiological processes in humans, such as: food digestion, fertilization of the ovum, blood clotting and dissolution of blood clots, immune response. however, their uncontrolled activity can evoke serious pathological conditions. therefore, serine proteinase inhibitors are considered to be a promising class of therapeutic agents. trypsin inhibitor sfti-1, on which we focused our attention in the last decade, is an attractive template for the design of such compounds. its primary structure is shown below: & 1 gly-arg-cys(& 2 )-thr-lys 5 -ser 6 -ile-pro-pro-ile-cys(& 2 )-phe-pro-asp& 1 the inherent feature of natural peptides and proteins is their low stability towards proteases, which seriously reduces their bioavailability. there is a growing need for the development of artificial biopolymers with diverse side chains, capable of mimicing peptide function. β-and γpeptides are an interesting class of peptidomimetics with significant chemical and biological properties. the present communication describes the chemical synthesis and inhibitory activity of a series of trypsin inhibitor sfti-1 monocyclic analogues (with disulfide bridge only) modified in p1 position by βand γamino acids and n-substituted β-alanine (β-peptoid units). the following mimetics of proteinogenic lys or phe were used: β 3 hlys, β 3 hphe, γ 4 hhlys, γ 4 hhphe, βhnlys, βhnphe. all compounds were synthesized manually on solid support. β-peptoid monomers were introduced into the peptide structure by two steps method [1] . newly obtained sfti-1 analogues modified in p1 position by β-derivatives of lys and phe were able to inhibit bovine β-trypsin and bovine αchymotrypsin, respectively, whereas the remaining ones (except for [βhnphe5]sfti-1) appeared to be inactive. the notion that early soluble aß intermediates are endowed with cytotoxic effects suggests that a major effort should be directed toward the inhibition of amyloid aggregation at very early stages. inhibiting aß self-oligomerization could, therefore, provide a useful approach to treating and controlling the pathogenic pathways underlying alzheimer's disease (ad). likely, agents that target the basic molecular recognition process preceding the formation of early intermediates are the most valuable candidates. we have conjugated a trehalose moiety to the known ß-sheet breakers pentapeptides lpffd. 1 trehalose has received a special interest because it has been found to be effective in the treatment of neurodegenerative diseases associated with peptide or protein aggregation. 2 the glycosidic moiety was covalently linked to different regions of the peptides' primary sequence, including the n-terminus or c-terminus or the aminoacid side chain. this new class of peptides showed an increased resistance to proteases. 1 in this work, the inherent ability of these peptides to recognize and bind the monomeric form of recently reported a d-amino acid-containing hiv protease inhibitor with a sulfonyl group showed an activity enhancement against drug resistant viruses. x-ray crystallographic study of the derivative revealed existence of four bridging water molecules. we suggest that the additional indirect interactions through water molecules induced the inhibitor's flexibility in binding conformation, keeping the affinity with the mutated proteases. oxalyamide, so-called oxamide, has two carbonyl oxygen atoms as hydrogen bonding acceptor similar to sulfonyl group, which is promising to interact with water molecules. to increase the numbers of bridging water molecules, we built-in two oxamide structures to both terminals of pseudo-symmetric compounds with hydroxymethylcarbonyl-hydrazide isostere. the derivatives were tested for inhibitory activity using wildtype hiv protease and a highly mutated protease with lopinavir resistance. we found that the loss of potency against the mutated protease was relatively small in the oxamide derivatives. the molecular dynamic simulations suggested the ability of bridging water formation of the two oxamide groups. optimization of the pna-synthesis using different bases for fmoc-deprotection s. rawer 1 , k. braun 2 , r. pipkorn 2 1 life technologies, darmstadt, germany 2 dkfz, heidelberg,germany pna (peptide nucleic acids) are considered as highly sensitive and specific tools for antisense strategies especially conjugated with cell penetrating peptides. individual designed shuttle systems can be applied in cancer diagnostics and possible therapy (1) . it is, however, undisputed that proper pnas' syntheses prove to be a challenge for coupling and fmoc-deprotection. due to the structure-formation the success of the synthesis depends strongly from parameters, like activator's quality and deproctection kinetics correlating to the length of the pna polymer spps product. using the example of the spps pna synthesis' results of the coding sequence of c-myc human exon ii, different bases, acting as fmoc-deprotection reagents, are compared and analyzed aiming at optimizing the pna synthesis strategy (2) peptidoglycans are central structural components of the cell wall of bacteria. several plant receptors are known to recognize peptidoglycan fragments. it is believed that these receptors form part of the defense mechanism against bacterial infections in several plant species. peptidoglycans consist of long chains of alternating β(1-4)linked glcnac and murnac moieties that are crosslinked by short, non-ribosomal peptides. these peptides consist of several d-amino acids and the symmetrical (r,s)diaminopimelic acid (meso-dap). in particular, the latter complicates the synthesis of peptidoglycan fragments due to the requirement for individually addressing the two pairs of functional groups. some chemical syntheses of peptidoglycan fragments have been reported [1] [2] [3] [4] , hhich involved multi-step formation of an orthogonally protected dap moiety, and elaborate oligosaccharide synthesis. here we present a new and simple approach to peptidoglycan synthesis which is based on the use of commercially available building blocks for the dap and oligosaccharide components. this allows easy access to a range of peptidoglycan fragments for structure-activity studies. the introduction of solid-phase peptide synthesis (spps) and the subsequent refinement of resins, linkers, coupling reagents and amino acid protecting groups allowed access to a wide range of peptides. therapeutic peptides, in particular, have benefitted from the maturation of spps, as complex peptides can be synthesized more efficiently in comparison to conventional solution phase synthesis. however, peptides containing multiple disulfide bonds often still remain difficult to make due to a lack of orthogonal cysteine protecting groups that can be used in routine spps. the cysteine protecting group s-tertbutyl mercapto (s-tbu) is commercial and orthogonal to other cysteine protecting groups. removal of the protecting group is facilitated by reducing agents (e.g. thiols or phosphines) and is stable to tfa and piperidine, hence compatible with fmoc/o-tbu peptide synthesis. however, the protecting group cannot be used in routine spps due to long deprotection times (4-24h) . in certain cases it has been shown to be impossible to remove due to proximity of bulky protecting groups and sensitivity to certain sequences. additionally, reports of desulfurization of s-tbu protected cysteine to dehydroalanine, by the use of prolonged exposure to reducing agents, show the limitations of this protecting group. the concept of cysteine protecting groups labile to reducing agents is promising due to orthogonality to other cysteine protecting groups and the limitations of s-tbu initiated an investigation into novel reductive cysteine protecting groups. herein, we introduce s-tmp as a novel cysteine protecting group that is very labile to reducing agents. the increased lability, in comparison to s-tbu, allows utilization of reducing agent labile protecting groups in routine peptide synthesis of disulfide containing peptides. as modern automated spps protocols allow the assembly of larger and increasingly complex peptides, a precise control of the coupling reactions is a crucial prerequisite in peptide synthesis. monitoring the progress of synthesis allows the detection of undesirable products caused by side reactions, incomplete couplings or deprotections. 1 although different methods have been developed for monitoring spps, we observed that the use of colorimetric test or continuous-flow uv absorbance of the reaction column effluent was not informative enough to identify difficult steps in the synthesis. in this study we demonstrate the usefulness of the combination of a mw-assisted mini-cleavage protocol and the uplc-esi-ms analysis for monitoring the quality of the reaction steps. as a proof of concept, based on this strategy, we monitored the synthesis of pthrp(1-34)nh 2 (synthesised by fmoc/tbu rt-spps, liberty™, cem), characterised by a cluster of arginine residues in the 19-21 region. 2 by the use of mw irradiation during the mini-cleavage protocol, we optimized time for mini-cleavages particularly in case of multi-arginine containing peptides, protected by pbf group. the results obtained by uplc-esi-ms showed that the complete removal of the pbf groups from the arginine sidechain residues required 1h at rt. on the other hand, the mw-assisted mini-cleavage monitoring let us to obtain final results just in 15 min, confirming that the use of microwave irradiation in mini-cleavages is an efficient strategy to monitor also difficult peptide couplings, such as multiarginine peptides. identification of some deletion sequences was helpful to recognise critical couplings in order to adopt more efficient coupling strategies and therefore to optimise the final yield and purity of the crude peptide. development of green sustainable chemistry is currently regarded as a challenge in science and technology to reduce the use of organic solvents and utilize less toxic solvents instead. water and aqueous-based solvent systems represent an increasingly significant choice for replacing traditional solvents in synthetic chemistry. until recently, peptide synthesis in aqueous solution has remained largely unexplored. this is because the most common building blocks are sparingly soluble in water and are considered inappropriate for in-water peptide synthesis. we have developed a method for solid-phase peptide synthesis in water, which utilizes water-insoluble fmoc-amino acids that are converted to water-dispersible nanoparticles. in this way, the solubility problem is overcome. our technology, which uses suspended nanoparticle reactants for the coupling reaction, offers many advantages in terms of reaction efficiency over inwater synthesis using water-soluble or non-disperse reactants. however, there are two main problems with this nanoparticle approach; (i) slow reaction rates compared to general peptide synthesis in ordinary organic solvents (ii) poor yields for the synthesis of long peptides because the protected peptide chains on the resin have a tendency to aggregate in water. mw assisted spps is particularly attractive because of the widespread availability of the new technology, including automated peptide synthesizers. a trial of mw assisted inwater solid-phase synthesis using non-disperse boc-amino acids has been reported by albericio previously. currently, fmoc-amino acids are routinely used as building blocks for solid-phase peptide synthesis. with this in mind, we have developed a mw irradiation procedure aimed at reducing reaction time and increasing reaction yield for in-water solidphase synthesis using water-dispersible fmoc-amino acid nanoparticles. and we demonstrated in-water solid-phase synthesis of difficult sequence peptide with mw irradiation. m. lebl, z. flegelova spyder institute praha, czech republic cotton was shown as a convenient solid phase support earlier 1-3 , but did not find wide acceptance by the peptide community. we decided to try its application as (i) a support of choice for the synthesis driven by combination of capillary forces and gravity, (ii) support for synthesis utilizing in situ neutralization boc based protocol, (iii) support for combinatorial synthesis based on easy labeling and physical separability of cotton substrate, and (iv) support for multisupport synthesis. -we have built a simple synthesizer in which the cotton carrier (functionalized thread) is placed inside the capillary tubing and the appropriate reagents are introduced by connecting the inlet with appropriate reagents. the speed of "pumping" the reagents is driven by the difference between the elevation of the inlet and outlet of the capillary tubing. -we have shown that boc solid phase synthesis utilizing in situ neutralization is compatible with cotton substrate and provides high quality products. combining with the fact that cotton by itself 4 acts as the self-association breaking agent, makes cotton a suitable carrier for synthesis of "difficult" sequences. -labeling of individual solid support particles can be easily based on the length of the cotton thread pieces, number and positions of knots, or their attachment to a secondary carrier. in addition, it is possible to synthesize peptides differing by the partial structure (alternative linkers, terminal modifications, etc.) in a mixture of classical resin with labeled cotton carriers, which are easily separable at the end of the synthesis. . use of microwave irradiation provides peptides in a fraction of time compared to conventional methods, and the peptides are also often generated in higher yield and purity. while microwave technology is particularly suited for the synthesis of "difficult" to synthesize peptides, this tool can routinely be used for the synthesis of a wide variety of peptides without the need for extensive method optimization. the focus of this study is to demonstrate how a peptide can be synthesized on a small scale (for example 25 μmol) up through larger scales (>1 mmol) with ease. as a biologically relevant model peptide the last 13 residues of the human platelet factor 4 protein (hpf4 57-10) was selected due to its significant antimicrobial activity. 1 however, the problem of developing a robust fmoc thioester method is that the deprotection of the fmoc group with base at each cycle is not compatible with an active ester at the c-terminus. many ingenious approaches have been developed to generate the required thioester peptide. 2, 3, 4 the most popular has been to use an nacylsulfonamide as a base and acid stable (safety-catch) linker for peptide synthesis. alkylation of the sulfonamide after peptide assembly makes the linker labile to cleavage with nucleophiles. 5 whilst popular, it has been plagued by notoriously low yields which originate from the incomplete acylation of the resin-bound sulfonamide with the c-terminal residue, incomplete alkylation of the sulfonamide and the incomplete thiolysis of the resin-bound protected peptide. in this poster we describe the development of a novel dual linker strategy 6 , involving anchoring of the sulfonamide linker to a standard acid-labile resin. this variation overcomes many of the current limitations of the sulfamylbutyryl linker approach and provides a simpler and scalable method for peptide ligation via fmoc spps. m. ziovas, d. tataraki, p. manousou, n. parveri, f. satoglou, d. gatos and k. barlos department of chemistry, university of patras, 26500 patras, greece solid phase peptide synthesis is traditionally performed by the attachment of the c-terminal amino acid through its α-carboxyl function on a suitable solid support and elongating peptide chain towards the amino terminal of the peptide by adding sequentially the amino acid residues in the gradually growing peptide chain. several thousands of publications and patents describe this methodology and its application for the production of peptide pharmaceuticals. in contrary to the attachment of the c-terminal carboxyl function, attachment of amino acids and peptides through an amino acid side-chain on suitable resins and their application in spps is described in a small number of publications and patents. most of these publications describe the attachment of the amino acids through a side-chain carboxyl group of asp and glu. in the present work peptides were synthesized very efficiently in high yield and purity by anchoring of side-chain hydroxyl, amino or thiol groups of amino acids, amino acid amides, amino alcohols or small peptides on resins of the trityl or benzhydryl type. several peptides of pharmaceutical interest, such as exenatide, octreotide, pramlintide, calcitonin, bivalirudin, insulin b-chain and others were produced as examples of this technology, either by the step-by-step procedure or by fragment condensation in solution and on solid phase. step given that some of these diseases are caused by a mutation and/or malfunction of an essential protein, a better understanding of the structure and function of such proteins will allow us to prevent, slow down or even cure these diseases. to increase our knowledge, the synthesis of the target protein, a fragment involved in its activity or interacting peptides that modulate the protein activity is often required. in some cases the preparation of a protein analogue that improves its efficacy is envisage. however, conventional solid-phase peptide synthesis methods have some limitations when attempting to achieve these complex sequences of considerable length. using novel technologies, such as a microwave-assisted solid phase synthesis, commonly found in many peptide synthesis labs, here we performed the step-wise solidphase synthesis of a protein holding more than 100 residues (d-vegf). this synthetic achievement indicates the suitability of this approach for synthesis of long proteins or their analogues. the detailed synthesis of the enatiomeric version of vegf and the selenomethionine substituted analogues of huprp (106-140),1 proteins involved in angiogenesis and prion protein amyloidoses respectively, are described as study cases, where the use of microwaves allow us to obtain them in a fast and efficient manner. therefore, the development of novel peptide analogues with enhanced in vivo stability could potentially provide therapeutic alternatives. the pharmacological evaluation of a bioactive peptide [des-gly 10 ,tyr 5 (ome),d-leu 6 ,aze-nhet 9 ]gnrh, analogue 1, is presented herein. in vitro (kidney mouse membranes) and in vivo (clinically relevant pharmacokinetic mouse model) bioassays were coupled to liquid chromatographytandem mass spectrometry. analogue 1, an agonist of the gnrh receptor with a binding affinity in the nanomolar range, caused testosterone release in mice that was acutely dose-dependent, an effect blocked by cetrorelix. repeated dosing studies in mice demonstrated that analogue 1 was well tolerated and had potency similar to that of leuprolide, based on plasma and testis testosterone reduction and histopathological findings. analogue 1 also shared with leuprolide similar significant antiproliferative activity on androgen-dependent prostate cancer (lncap) cells. on the basis of pharmacokinetic advantages, we expect that analogue 1 or analogues based on this new design will be therapeutically advantageous for the treatment of cancer and endocrine disorders. cortexin is a polypeptide drug isolated from cattle and porcine brain cortex. cortexin is effective in monotherapy and in combination with traditional methods of treatment. cortexin produces tissue-specific, regulatory, and reparative effects on the brain cortex and contains active low-molecular-weight neuropeptides (<10 kda) penetrating through the blood-brain barrier. cortagen is a tetrapeptide h-ala-glu-asp-pro-oh (geropharm) produces nootropic and neuroprotective effects. oleylcortagen is a lipophylic analog of cortagen c 17 h 32 o-ala-glu-asp-pro-oh was created for increased proteolytic stability and increased penetrating through the blood-brain barrier. the main aim of our investigation is the analysis of psychopharmacological profile of 3 peptide preparations in comparison with piracetam. have been shown oleylcortagen (1 mg/kg) and piracetam (200 mg/kg) possess activating effect on motor and research components of behavior in «open field» test. two of peptides (oleylcortagen, cortexin) decreased period of immobilisation and demonstrated antidepressant effects on rat behavior in the porsolt's test, on other hand cortagen demonstrated depressant action. therefore, the significant psychoactivating properties are typical for oleyl-cortagen, cortexin. the mechanism of the action of these peptides can be explained from the viewpoint of the regulatory cascade. they produce a direct information impact on cell structures of the brain, and then promote release of the regulatory peptides, which in turn, induce the release of the next group of peptides. neurology, queen square, london wc1n 3bg, uk one of the hypotheses of alzheimer's disease neuropathology involves beta-amyloid (βa) binding with proteins on neuronal cell surface which leads to cell lysis and amyloid plaque formation. according to the latest data α7-type of the nicotinic acetylcholine receptor (achr) and the prion protein can be the target for betaamyloid toxicity [1, 2] . aggregated βa causes many pathological changes in cultures of mixed neurons and astrocytes such as sporadic cytoplasmic intracellular ca 2+ -signal, activation of reactive oxygen species (ros) production and cell death. in the present work we demonstrated the ability of affinity purified antibodies to synthetic fragment 173-193 of α7-subunit of the achr (achrabs) or to peptide 95-123 of the prion protein (prpabs) to protect cells from βa induced cell death. we also showed that both antibodies did not block βa induced ca 2+ -signal in astrocytes. however, preincubation of cortical co-culture of neurons and astrocytes with achrabs or prpabs significantly reduced the rate of caspase 3 activation and the rate of βainduced ros production via modulating nadph-oxidase. more detailed research of involvement of α7-type achr revealed that α-bungarotoxin was also very effective in the inhibition of caspase 3 activation and superoxide production. the observed positive effect of antibodies to α7-type achr or to the prion protein gives an additional explanation regarding the involvement of these proteins in ad pathology and provides new approach into an anti-ad vaccine design. capturing and macrophage-aided clearance of amyloid beta by surface modified proteineous particles m. richman, s. rahimipour department of chemistry, bar-ilan university, ramat-gan 52900, israel imbalanced homeostasis and oligomerization of amyloidβ (aβ) peptide in the brain are hallmarks of alzheimer's disease (ad). microglia and macrophages play a critical role in ad progression by clearing aβ from the brain or inducing inflammation. recent evidence suggests that the phagocytic pathway of aβ may be defective in ad microglia/macrophages that contributes to the build-up concentration of aβ in the brain. 1,2 therefore, efforts have been directed toward developing treatments that trigger these cells to clear aβ through alternative mechanisms. we have recently demonstrated that protein microspheres modified at their surface with multiple copies of an aβrecognition motif can strongly bind aβ, inhibit its aggregation and directly reduce its toxicity by sequestering it from the medium. 3 here, we describe how the aβ-bound microspheres can stimulate microglial cells and be phagocytosed through a mechanism that is distinct from that of aβ. the phagocytosis was mostly effective with microspheres having diameter size of about 0.7-1 mm and introduction of polyethylene glycol to the surface of the microspheres changed the kinetics of the phagocytosis. moreover, while aggregated aβ induced a significant inflammatory response that was manifested by the release of tnf-α from the microglial cells, the aβ-bound microspheres dramatically reduced the amount of the released cytokine. our data suggest that surface-modified microspheres could be utilized to detoxify other pathogenic or misfolded proteins that their accumulation may lead to genesis of other diseases. vasoactive intestinal peptide (vip) and its derivatives have been thought to be promising drug candidates for airway inflammatory diseases. however, the therapeutic potential of vips is highly limited because of rapid metabolic degradation and systemic side effects following systemic administration. previously, to overcome these drawbacks, our group developed a novel vip derivative, [arg 15, 20, 21 , leu 17 ]-vip-grr (ik312532), with improved metabolic stability (1), and respirable powder (rp) formulation of ik312532 (ik312532-rp) for pulmonary administration (2) . these attempts successfully led to enhanced pharmacological effects of ik312532 in the airway system and reduced systemic exposure; however, further chemical modification of ik312532 with a focus on metabolic stability might provide better clinical outcome. the present study aimed to design a pegylated vip derivative with improved metabolic stability and to develop its respirable powder (rp) formulation for inhalation therapy. ik312532 was chemically conjugated with peg (5 kda, p5k), the physicochemical and biochemical properties of which were characterized by cd spectral analysis, binding assay, and metabolic stability. the rp formulation of pegylated ik312532 (ik312532/p5k) was prepared with a jet mill, and in vitro inhalation performance and in vivo pharmacological effects in antigen-sensitized rats were also evaluated. the cd spectral analysis demonstrated that peg conjugation had no impact on the solution structure of ik312532. although receptor-binding activity of the ik312532/p5k (ic50: 82 nm) was estimated at ca. 30-fold less than that of ik312532 (ic50: 2.8 nm), metabolic stability for the ik312532/p5k was highly improved. according to the laser diffraction and cascade impactor analyses, ik312532/p5k-rp had fine in vitro inhalation performance. insufflation of ik312532/p5k-rp (150 μg of ik312532/p5k) in antigen-sensitized rats resulted in marked attenuation of inflammatory events, as evidenced by significant decrease of inflammatory biomarkers and granulocyte recruitment in pulmonary tissue at 24 h after antigen challenge. from these findings, pegylation of vip derivative, as well as its strategic application to the rp formulation, might be a viable approach to improve its therapeutic potential for treatment of airway inflammatory diseases. the previous studies have shown that trkb (tropomyocin receptor kinase) acts as an oncogenic agent and its binding to bdnf (brain derived neurotrophic factor) activates signaling angiogenesis of tumor proliferation [1] . for finding the most stable and potentially effective peptides against the trkb, we applied the following protocol. at the first step of this protocol we designed a peptide library by using sequence tolerance method in rosetta 3.3 package, then peptide energy optimization performed by backrub protocol for finding the most stable peptides. the five best peptides in energy optimization selected based on backrup scores by using r package [2] . 3d-structure prediction of the selected peptides was performed by using molecular dynamic in hyperchem 7 software. docking of peptides with trkb receptor was carried out in haddock software. we used cyclotraxin, a selective trkb inhibitor as positive control for this protocol. cyclotraxin and the peptides were compared by anova or t-test. the peptides are going to be tested against the trkb in an in vitro model. dirucotide (mbp 82-98 ) is a synthetic peptide analog of , that consists of 17 amino acids and tested in a phase trial were failed to reach his tolerance level on previous phase ii in rpms patients. one of the major disadvantages of peptide therapy is the activation of proteolytic enzymes, leading to peptide degradation. to address this problem cyclic peptide analogues have been synthesized. thus we synthesise a linear and cyclic analogues of dirucotide. the two analogues were synthesized by changing the amino acid residue at position 91 from to the synthesis of the linear peptide, as well as of the cyclic one, was carried out by the fmoc/tbu methodology, utilizing the 2-chlorotrityl chloride resin (cltr-cl). the purification was achieved using semi-preparative rp-hplc and the identification was assessed by analytical rp-hplc and by mass spectrometry (esi-ms). the linear and cyclic peptide analogues will be used in human t-cell cultures to test their immunogenicity in patients versus healthy controls. 1 in the first approach a reporter moiety was introduced to diagnose and treat cxcr4 related diseases. therefore, an anchor point to attach additional molecules to the ligand was elucidated. using sar studies to optimize the linker from the ligand to the detectable moiety the excellent receptor affinity could be retained. in a final step the reporter moiety was introduced to give a ligand for diagnosis via pet imaging and for possible endoradiotherapeutic applications. 2 originating from the dimeric motif present in many active cxcr4 ligands several dimers were prepared using a monomeric ligand identified in the prior study. comparison of monomers and dimers yielded a possible subsite binding mode explaining why the dimers exhibit enhanced affinity using a model derived from the origins of the monomer. 3 several peptidomimetic modifications were introduced to the ligand to reduce the peptidic structure. in a conformationally guided approach introduction of a peptoid motif could enforce a single active conformer that was enhanced through subsequent modifications. this yielded a compound 100 times better than the original cxcr4 antagonist which is the most affine cxcr4 ligand reported so far. our previous studies have demonstrated that pace4 represents a potential therapeutic target for the treatment of prostate cancer 1 . moreover, we have developed potent and selective pace4 inhibitor, (20-fold specificity over furin), known as multi-leu or ml peptide, which has a significant inhibitory effect on the proliferation of prostate cancer cell lines. peptide-based drug candidates can be limited by their poor metabolic stability and low bioavailability. thus, we performed structure-activity relationship studies to improve the pharmacokinetic properties of our ml inhibitor. we have designed and synthesized new ml peptide analogs having various chemical modifications. first, based on our previous results, we combined the most effective modifications of position p8 (d-amino acids) and p1 the arginine mimetic 4amidinobenzylamine (amba) to improve overall properties of our leading compound. second, the n-terminus of the resulting analogs was modified with a fatty acid, in order to enhance their cell permeability properties. third, we modified the inhibitors with a peg moiety to increase their stability and bioavailability. we tested the inhibitory activity, stability in plasma, cellular uptake, and cytotoxicity of each inhibitor. the results of this study demonstrate that the presence of the n-terminal extension (c8 or peg8) does not affect activity of our inhibitors. on the other hand, we show that introduction of the peg moiety does not increase cytotoxicity of ml analogs. it is interesting to note that the pegylated analog ac-peg8-d-leu-lllrvkr-amba has better cell-permeability activity than its counterpart without peg unit. this combination of pharmacological properties makes our new ml analogs promising candidates for the development of potential anti-prostate cancer agents. [1] peripheral coadministration of rf9 with opioid analgesics led to confirm the involvement of npff receptors as a part of the antiopioid system. indeed, rf9 was able to reverse the opioid induced hyperalgesia in rat (randall selitto test). then, a complete structure-activity relationships analysis was performed with rf9, assessing the involvement of each moiety for affinity and selectivity towards both npff receptors. a first exploration of the n-terminus part of rf9 (>80 synthesized derivatives) led to replace the hydrophobic adamantane moiety by a hindered aromatic group, providing a subnanomolar npff1 ligand with more than two log-units selectivity against npff2. then, the removal of the cterminal amide function led to reduce the dipeptide arg-phe-nh2 into an arginine derivative. in spite of an initial loss of affinity, optimization of the phenethyl moiety at the cterminus part of arginine led to non-selective nanomolar ligands for both npff1 & 2 receptors. next, we applied efficient methodologies in order to synthesize non-natural analogs of arginine, leading to various compounds exhibiting selectivity for either npff1 or npff2 receptors. in particular, compound rf313 was identified as a selective npff1 antagonist (npff1, ki = 64 nm; npff2: ki > 13 μm). lacking of analgesia properties, oral administration of rf313 (1 mg/kg per os) to rats was able to fully reverse fentanylinduced hyperalgesia. rf313 is the first orally available npff1 antagonist capable of reversing opioid induced hyperalgesia at low dose. moreover, this result allows identifying for the first time npff1 receptor as a key-partner of the anti-opioid system. administration of multiple antiplatelet agents has become the mainstay in the treatment of acute coronary syndromes in everyday clinical practice. we have previously reported significant antiplatelet effects of novel synthetic peptides' single administration on experimental carotid artery thrombosis in rabbits 1 . in the present study we sought to investigate the peptides' effects when administered in marginally effective doses (significantly lower than those utilized in the past), in animals that had previously received low doses of aspirin. the peptides when co-administered with aspirin preserved the carotid artery's blood flow, in contrast to the total artery occlusion observed in animals receiving aspirin and placebo. blood flow at 90 min after electrical stimulation was reduced to 56.7±7.9% and 33.2±0.3% in the ymesradr and psrcdcr-nh2 groups respectively (p<0.001 vs aspirin and control). thrombus weight was significantly reduced in animals receiving ymesradr and psrcdcr-nh2 versus aspirin and control (3.9±0.3 mg and 3.1±0.4 mg, vs 7.8±2.2 mg and 5.7±0.8 mg respectively, p<0.05). platelet aggregation was significantly inhibited in the ymesradr and psrcdcr-nh2 groups by 36.0±14.1% and 45.0±12.0% for adp (p<0.05 vs aspirin and control), and 35.5±6.3% and 54.2±5.6% for aa (p<0.05 vs aspirin and control), respectively. blood loss did not significantly differ among the various groups. administration of novel synthetic peptides, even at marginally effective doses, in animals previously treated with low doses of aspirin results in enhanced antiplatelet effects in an experimental model of arterial thrombosis. the study of peptide metabolism is particularly important when examining anticancer peptides; it can provide pivotal clues for the evaluation and improvement of stability of a peptide drug leading to enhanced pharmacokinetics and efficacy. gnrh analogues are used for the treatment of prostate cancer. as with other peptides a drawback is their short half-life due to their metabolic degradation. in order to examine the stability of these analogues we have developed several in vitro peptide stability and metabolism assays using specific tissues, isolated membranes, cancer cells that are analyzed subsequently using lc-ms/ms based approaches. such in vitro studies are followed up with pharmacokinetic studies in mice in order to establish the correlation between in vitro and in vivo approaches. the kidney is the main metabolic organ for peptide metabolism and for that reason we employed a peptide stability and metabolism assay previously described by our group using isolated mouse kidney membranes for the evaluation and comparison of different gnrh analogues. we tested gnrh analogues in other tissues such as mouse plasma, which is the "distributing" tissue for these drugs and mouse brain homogenate, a tissue known for its abundance in peptidases and relevance for centrally mediated effects. stability studies were also performed in cancer cells. in all cases lc-ms/ms based assays were developed for measurement of peptide drug and the resulting metabolites. for triptorelin, and a series of gnrh analogues, degradation and metabolite formation was studied by our mouse kidney membranes assay. studies of coadministering the peptide of interest with inhibitors that are presumed to block the metabolism in mice are ongoing. the vulnerability of gnrh analogues was verified after incubation with plasma and brain homogenate and by metabolite identification we obtained clues about the key cleavage sites. the described in vitro/in vivo protocols provide valuable information that could lead to the synthesis of more stable anticancer peptides with improved anticancer efficacy. in this work, we explored the use of a high-throughput synthesis and screening approach with peptide arrays to identify and structurally optimize shortened hiv-1 fusion inhibitors. the peptide array technology involves miniaturized synthesis of immobilized peptides, followed by affinity testing with a five-helix bundle, as a mimetic of the fusogenic gp41 protein. this exercise resulted in the identification of a class of truncated peptides which demonstrates a surprisingly high antiviral potency, despite the absence of the pocket-and the lipid-binding domain. the propensity of these peptides to adopt the bioactive α-helical conformation in solution as determined by circular dichroism, could be the key factor for this unexpected potency. these peptides are promising leads for the treatment and prevention of hiv. the pathological role of platelets in cardiovascular disease (cvd) is well established. platelets secrete adp to recruit additional platelets to a thrombotic site. we have previously identified novel cell-permeable peptide modulators of platelet function by using a bioinformatic screen based on patterns of evolutionary conservation in transmembrane proteins 1 . in this study we further explored peptides derived from cadherin cell adhesion molecules. we explored a range of 14 overlapping peptides derived from different cadherins varying from 6-15 amino acids long. peptides are synthesized and analyzed in a high-throughput platelet adp secretion assay. peptides (0.05-50μm) were assessed in the presence and absence of thrombin receptor activating peptide (trap;4μm). we identified cadh-5 and 6 proteins, but not cadh 1 or 2 in human platelets using western blotting and mass spectrometric analysis. peptides derived from paralogous juxta-membrane, cytoplasmic regions of these cadherins are potent modulators of platelet secretion. by systematically deleting amino acids from c or n-terminus of active peptides, we established that the minimal functional sequence for biological activity was a short six-residue motif, which corresponds to the known catenin-binding region of cadherin tails (kepllp) 2 . peptides alone have no biological activity. however, they potentiate the response induced by the platelet agonist trap at low doses. thus we have identified a cadherin-derived peptide that can modulate platelet secretion events. this highlights a previously unknown role of cadherins in the regulation of platelet function. agents that interfere with cadherin signaling in platelets might have a therapeutic role in cvd. ageing of the brain leads to impairments in cognitive and motor skills, and is the main risk factor for several common neurological disorders such as alzheimer's disease (ad) and parkinson's disease (pd). altered protein handling (proteolysis, repair system, chaperones) forms a basis for a large number of protein conformational disorders. extra-and intracellular, as well as intranuclear accumulation of abnormal proteins, in the form of protein inclusions and aggregates, and dysfunction of the quality control mechanisms are common in all these disorders. alterations in protein homeostasis occur with age, causing molecular changes such as protein misfolding and aggregation. many biologically active proteins lack stable secondary and tertiary structure, these are called intrinsically disordered proteins (idps), some of them (e.g. β-amyloid, α-synuclein) are coupled to neurodegenerative disorders. idps exist as assemblies of rapidly fluctuating structures undergoing coupled folding and aggregation process. protein aggregation is characterized by polymorphism, where a mixture of soluble oligomers, amyloid fibrils and amorphous aggregates is the final product. soluble oligomers are inevitable formed during the self-association process and might initiate the neurodegenerative cascades of ad, pd and similar diseases. the emerging consensus that protein misfolding (leading to idps) is the cause of several neurodegenerative disorders now offers the opportunity to develop a general therapy. soluble oligomers with id regions are potential drug targets. recently short peptide fragments and small peptidomimetic molecules have been found also in our laboratory; these molecules bind to the id regions of β-amyloid and are putative drug candidates. precise control of bleeding is ensured by anticoagulant mechanisms, which under normal conditions prevail over coagulants mechanisms. disrupting the balance between procoagulant and anticoagulant systems due to congenital or acquired defects leading to thrombotic disorders. anticoagulants are substances that inhibit blood clot formation. their action consists in inhibiting the synthesis of prothrombin, the substances forming thrombus as well as some coagulation factors. many peptides and proteins with different molecular weight, such as antistasin (ats), ghilantens, hirudin, etc. showing high anticoagulant activity are isolated from salivary glands of ticks and leeches. they inhibit the action of serine proteinases from blood coagulation cascade. this creates an opportunity for targeted synthesis of low molecular weight analogues of some of these proteins, which can be used in the prevention and treatment of thrombotic disorders. ats is competitive, slow-binding inhibitor of factor xa. it is well known that blood coagulation could be blocked at different stages of the coagulation cascade through inhibition of various enzymes. therefore, it is interesting to determine the place of action of newly synthesized antithrombotic agents in the blood coagulation cascade. this can be done by determining the inhibitory constants of newly synthesized peptides on different enzymes of this cascade. herein we report on our kinetic investigation of newly synthesized peptide amides, analogues of isoform 2 of ats 1 . ki, km, vmax and type of inhibition on the factor xa, thrombin and plasmin were determinate. some interesting differences between type of inhibition of ats, free acids and amide analogues of ats were revealed. to evaluate the relative anti-platelet aggregation activities of each peptide, the lebetins were chemically synthesized and fully characterized. here we described the synthesis, the solution structure of lebetin g1-g38 from the venom of vepera lebetina by 1 h bidimensional nmr and the relation structure-activity. this peptide has been demonstrated to be associated with a potent anti-platelet aggregating activity. the g1-g38 three dimensional structure consists in a compact β-bulged hairpain core from which emerges one loop and the cterminus and the n-terminus. we report on an approach whereby ligands are designed to bind and stabilize the 13-26 region of aβ in an α-helical conformation. these ligands reduce aβ toxicity to cells in culture and to hippocampal slice preparations. in addition, when these inhibitors are administered to drosophila melanogaster expressing human aβ (1-42) in the central nervous system, a prolonged lifespan, increased locomotor activity, and reduced neurodegeneration is observed 1 . stabilization of the central aβ α-helix appears to counteract polymerization into toxic assemblies and indicates that this approach holds promise for the development of orally available compounds against alzheimer's disease. encouraged by the above results we are currently developing a second generation of designed ligands. this involves synthesis of different new peptoids and unnatural amino acids. additional support for the concept comes from recent molecular dynamics simulations that also uncover details of the mechanism of unfolding of the aβ central helix 2 as well as retardation of the folding in presence of ligands designed to interact with the native helical conformation 3 . synthesis and methodology for new ligands, which includes synthesis of novel amino acids, will also be presented. triostin a is a well-known natural product with antibiotic, antiviral, and antitumor activities. it inhibits rna synthesis by bifunctional intercalation into dna base pairs through its two quinoxaline units showing cpg selectivity. triostin a must adopt an altered conformation upon dna bisintercalation that is substantially different than its preferred native x-ray or solution conformation. this fact suggests that the destabilizing conformational change in the cyclic octadepsipeptide counteracts much of the gains derived from a second intercalation. nonetheless, the wide range of pharmacological activities exhibited by this compound prompted interests in identifying novel and additionally potent lead compounds with improved pharmacokinetic properties for clinical applications. herein, a library of twelve simplified triostin a analogues has been synthesized by solid-phase peptide synthesis. the introduction of the key quinoxaline units was carried out in solution. the analogues' conformation corresponds to the staple form that bisintercalator cyclic (depsi)peptides adopt when binding to dna and, in addition, some of the synthesized compounds showed improved solubility. our library was evaluated for its antiproliferative activity against four human cancer cell lines and one analogue showed greater cytotoxicity than triostin a and even comparable activity to doxorubicin, a very commonly used drug in cancer chemotherapy nowadays. surprisingly, little is known about its mechanism of degradation in solution or the degradation products. a recent study identified monomeric polysulfides and dimeric degradation products, postulated to derive from β-elimination followed by deamidation and dimerization. 1 we recently reported that degradation of oxytocin and its analogues in aqueous solution at ph 7.4 produced monomeric polysulfides with up to 6 sulfur atoms as well as dimeric products. 2 unexpectedly, incubation of ot or of various analogues modified in position 1 resulted in identical dimeric degradants. we concluded that β-elimination via breakage of the c-s bond of cys1 must be a key step of the process, and that the resulting δala 1 residue would have to undergo further modifications to yield the same dimeric products independently of the substitution of the n-terminal nitrogen. here we further clarify the degradation mechanism and propose a structure for the dimers. we postulate that hydrolysis of the δala 1 residue yields an n-pyruvoyl linear peptide, which loses one sulfur atom and subsequently forms dimers, which we found are linked by one disulfide bridge and one non-reducible bond. the putative linear n-pyruvoyl oxytocin intermediate was synthesized and found to degrade to the same dimers as the ones in the incubations of ot. a [u-13 c]cys 1 ot analogue gave degradation products with 13 c-nmr spectra consistent with a non-stereospecific aldol-type condensation. detailed experimental procedures, structures of the degradants and the postulated mechanism of ot degradation in near neutral solutions will be presented. inserm u765 paris, france αiibβ3 is the main platelet integrin and is responsible for platelet aggregation. a lipid-modified peptide corresponding to αiib intracellular sequence 1000-1008 (palmitoyl-k-l 1000 eeddeege 1008 , pal-k-1000-1008), is platelet permeable and inhibits human platelet aggregation induced by thrombin 1 . ymesradr, a peptide corresponding to the extra-cellular sequence 313-320 of αiib, is a platelet activation and aggregation inhibitor 2 . the aim of the present study was to investigate the cooperativeness of the intracellular and extra-cellular peptides on platelet aggregation and their effect on the phosphorylation of fak and erk. pal-k-1000-1008 together with the extracellular ymesradr peptide, at concentrations lower than their ic50 values, showed cooperative inhibition of platelet aggregation. the peptide combination inhibited also fibrinogen and pac-1 binding to activated platelets. fak phosphorylation is a postaggregation event related to outside-in activation of the receptor. the combination of peptides inhibited fak phosphorylation. erk phosphorylation is independent from platelet aggregation, and is enhanced by rgd-peptide inhibitors. the combined peptides inhibited erk2 phosphorylation. ovarian cancer (oc) is considered a rare disease and represents the fifth most common cause of death from cancer in women. the standard first-line treatment consists of a combination of paclitaxel and carboplatin (ddp) or carboplatin alone. in the case of progressive disease or drug resistance to platinum-based agents, either alone or in combination, investigational compounds should be used (1) . the mechanisms behind acquired resistance to ddp and its derivatives are not clear yet, although it is evident that the process is multifactorial, including enhanced dna repair processes. some peptides designed from the interface subunit of the human thymidylate synthase (ts) have been identified recently (2), as effective anticancer agents against sensitive and resistant oc cells. one of them was also able to recover the cellular sensitivity towards cisplatin in resistant oc cells in the μm range. to improve its potency and selectivity structural studies have been performed in combination with cellular assays aimed at understanding the mechanism of action. a label-free quantitative proteomic approach has been undertaken to study the effects of the peptide on the proteins involved in the modulated metabolic pathways, in particular those involved in the folate metabolism. structure-activity relationships (sar) have been performed to improve the lead peptide pharmacodynamics. all the compounds have been assayed and a protein profile set was studied to mark and validate their behavior as inhibitor of oc cell growth. hepatitis c is a liver disease provoked by a virus known as hcv. the disease is insidious. hcv causes anorexia, nausea, vomiting, fever, fatigue and jaundice. in about 40% of sufferers the disease is short, but others become chronic. in the chronic form in about 20% of cases the final result is cirrhosis of the liver and in the remaining 20% it leads to liver cancer. hcv is a very serious problem today. about 3% of people infected with hcv worldwide, i.e. about 4 million are residents of europe. 170 million people carry the disease as a chronic illness with the potential to develop into cancer in their liver. all these people represent a "reservoir" for storage and distribution of hcv. ribavirin, the nucleoside analog 1-β-d-ribofuranosyl-1,2,4triazole-3-carboxamide, known by the trade name virazole (also known as rebetron in combination with interferon-α), exhibits antiviral activity against a variety of rna viruses (paramyxoviruses, flaviviruses, etc.) as well as some dna viruses. in humans ribavirin is currently used in combination with interferon-α to treat hcv infections. this lack of strict specificity and a broad spectrum of activity are due to its multifunctional mechanism of action against viruses. these characteristics have made ribavirin a drug of substantial research interest. unfortunately, ribavirin shows a significant toxicity, causing bleeding in accumulation [1] . herein, we report a total synthesis of modified in position 5' of ribose residue, ribavirin in order to be further linked to cell penetrating peptides (cpps). in addition the synthesis of some cpps as well as bonding between two parts of final hybrid molecules will be reported. in our case the design of new hybrid molecules is done in order to: (a) vectorize ribavirin into liver cells; (b) transport ribavirin molecule trough cell membrane and (c) decrease toxicity of ribavirin. to obtain oligomeric aβ peptide, our laboratory uses a precursor depsipeptide of aβ. this precursor, termed as "iso-aβ" has an ester bond between the side chain of ser 26 and gly 25 . at physiological ph this ester bond becomes an amide bond via an o→n acyl shift. binding partners by which the oligomeric aβ mediates its toxic effect has not been yet investigated in the proteome or subproteome level. we used protein array technology to study the interaction of oligomeric aβ with 8163 recombinant human proteins, immobilized on a protein chip. aβ binding proteins were identified with the aid of a monoclonal aβ antibody. altogether 324 proteins were found to interact with our aβ-oligomers. these proteins were grouped according to their function. one of the major groups contained 24 proteins participating in translation. these proteins were found in ribosomes. to prove our proteomic results ribosomes from rat hippocampus were isolated. elisa experiment revealed that aβ binds to ribosomes in a dose-dependent manner. using the sequence of the 324 aβ-binding proteins a homology search was performed to find oligopeptides, that possibly bind to aβ. based on these sequences a peptide chip containing hexapeptides was prepared. aβ interacting peptides were identified with a monoclonal antibody. several peptides were synthesized and tested on mtt assay. two out of four compounds inhibited the toxicity of aβ on rat hippocampal slices. summarizing our results aβ binding proteins and peptides were identified. knowledge about aβ binding proteins can help to understand the pathogenesis of ad, such us the possible involvement of ribosomes. oligopeptides can be lead compounds of future drug development. huge proteolytic complex named proteasome catalyzes protein degradation in every eukaryotic cell. it consists of 31 subunits forming four stacked rings and one or two regulatory caps. two inner rings of the proteolytic part contain three catalytic β-subunits that possess different substrate specificity. higher vertebrates can express γinterferon-inducible immuno-β-subunits. proteasome plays an essential role in continual turnover of intracellular proteins and in antigen processing. autoimmune diseases such as multiple sclerosis and its murine model eae are believed to rise from breakdown of tolerance of the immune system. it assumed that immunoproteasome could play an important role in autoimmune diseases. several classes of chemicals proved to be inhibitors of proteasome and the most active are boronate peptide derivatives. these inhibitors totally inactivate proteasome and result in full stop of intracellular protein turnover and cell death via apoptosis. another class of inhibitors, epoxy ketones, was shown to be more selective for immunoproteasome and could be used not for full stop of proteasome function, but for fine tuning of altered proteasome functioning. we examined properties of several inhibitors of four different classes, namely peptide boronate bortezomib, peptide aldehyde mg132, lactam lactacystin, and peptide epoxyketones epoxomicin, mg132ek, uk101 and pr-957. for inhibition experiments we used proteasome isolated from eukaryotic cell lines cho, nso and hek, treated and non-treated with γ-interferon, as a model cells contatinig constitutive and immunoproteasome. the upregulation of proteasome immunosubunits was revealed in cho and nso cells treated with γ-interferon. the ic50 values for all studied inhibitors were obtained, and ki in some cases were calculated. the epoxyketones were shown to selectively inhibit in submicromolar concentrations the proteasome sample which contain high amount of immunosubunits. in order to find an effective antimalarial, this study refers to some angiotensin ii (aii) analogues which were considered the important physicochemical characteristics described by silva et al. 1 to verify the biological activity against plasmodium gallinaceum and to understand the hydrophobic cluster influence, explained by tzakos et al. 2 these analogues were synthesized and characterized as described by silva 1 , as well as the biological assays and comprises, to verify: the hydrophobic cluster activity -a) drvyhipf; b) drvypr; c) ryhipf and d) fphiyvrd; the importance of these residues in aii molecule -e) rypf; the importance of aromatic residues -f) yhpf and the action of these hydrophobic residues, when interacting with the parasite membrane -g) vipf. it was observed that in a (94% of bioactivity), the phenol group of tyr is close to imidazole group of his that could promote a hydrogen bond formation. besides that, could occur van der waals interactions between ile and phe residues due its proximity and non-polar characteristic. these interactions could not be effective in native aii (88%) 3 , because ile residue promote a steric influence on the organization of his and tyr residues 4 that not exist in b (57%). in c (74%) and e (72%) analogues, the influence of the arg residue could promote a cation-π interaction with tyr residue 5 and the cluster may have suffered slight destabilization and its antiplasmodial activity was compromised subtly. in d (12%), the electrostatic change, obtained with the total inversion can have disordered its interaction with parasite membrane, since it is not related to membrane receptors, because d-aii presented 91% of biological activity. moreover, hydrophobic and aromatic residues importance was confirmed through the results obtained 93% and 89% of activity, with g and f, respectively. we conclude that hydrophobic cluster modifications and interactions of amino acid side-chain influences in the biological activity. closed joint-stock company "vertex", st-petersburg, russia creatine (cr), a small molecule synthesized in the kidney, liver and pancreas plays important role in atp synthesis, replenishing its store even in the absence of oxygen. cr is able to protect brain cells against ischemic damage; however it has poor ability to penetrate the blood-brain barrier without specific carrier protein. thus, synthesis of stable hydrophobic derivatives capable of crossing the bbb by alternative pathway is of great importance for the treatment of different neurological diseases including stroke, traumatic brain injury and hereditary crt deficiency. here we describe the synthesis and biological activity of new hybrid compounds -creatinyl amino acids. originally the title compounds were synthesized by guanidinylation of sarcosyl peptides. however, for large scale synthesis better results can be obtained using direct cr conjugation with amino acid or peptide derivatives by isobutyl chloroformate method. addition of equivalent amount of ptoluenesulfonic acid as lipophilic counterion ensures efficient cr dissolution in dmf along with its simultaneous protection towards intramolecular cyclization. it excludes the application of expensive guanidinylating reagents and permits to simplify the synthetic procedure. purification of final product and its conversion into appropriate salt form can be achieved by iec followed by crystallization from organic solvents. synthesized creatinyl amino acids and peptides exhibited significant biological activity in different assays including platelet aggregation test, ischemic stroke and nano2-induced hypoxia model. one of the most effective compounds -creatinyl-glycine ethyl ester increases life span of experimental animals more than two times in hypoxia model and has neuroprotective action in brain stroke model when applied both before and after ischemia. these data evidenced that creatinyl amino acids can represent promising candidates for the development of new drugs useful in stroke treatment. the efficient recognition and destruction of tumor cells via specific cellular markers is a major goal in cancer therapy. various growth factor receptors such as egfr, hgfr, vgfr and their downstream signaling networks have been proven to be effective molecular targets, as they are frequently involved in cancer proliferation and metastasis. downregulation of these receptors and/or blocking their signaling pathways have clear anti-tumoral effects. 1 drugs based on monoclonal antibodies (mab) targeting such cell surface receptors have attracted a lot of attention as a new generation of therapeutics. however, their production is costly and identifying new, variable routes to modified molecules with similar properties is currently a major focus. 2, 3 here we present an approach to chemically synthesize a molecule that combines the mode of action of antibodies with the advantages of smaller, chemically accessible molecules. these "synthetic antibody" (sab) molecules contain a chemoattractant that activates the innate immune response and resembles the fc domain of a typical antibody. specificity is imparted by two binder peptides that assume the function of the variable antibody domains and bind to a cell surface target. the fc and fab domains of the sab molecules are connected via polyethylene glycol linkers. sab molecules are prepared by solid phase synthesis, a flexible technique that allows fast production, full control of their properties and targeting two different cell surface receptors (bispecific tumor targeting). they are currently tested in vitro and in vivo for their effect on the innate immune system, general toxicity and selective binding to cancer cells. the key enzyme in the processing of polyproteins translated by viral rna genome of sars-cov is a 33kda protease called 3c-like protease (3cl protease). sars 3cl protease is a cysteine protease containing a cys-his catalytic dyad, and cleaves precursor poly proteins at as many as 11 conserved site involved a conserved gln at the p1 position and a small amino acid (ser, ala, or gly) at the p'1 position. due to its functional importance in the viral life cycle, sars 3cl protease is considered to be an attractive target for drug design against sars. recently, we found tetrapeptide aldehyde, ac-thr-val-cha-his-h, showed high inhibitory activity with ic50 value of 98 nm toward 3cl-r188i mutant protease 1,2 . to compare the inhibitory activity of small compounds with those containing active functional groups, we synthesized serine-derivatives within the essential functional groups and evaluated its inhibitory activity. the synthetic scheme was started from fmoc-ser(tbu)-oh, following modification of c-terminal carboxyl group with p2, n-terminal amine with p4 and side chain alcohol with p1 functionalities. 5 steps overall reaction led to obtain 44 novel serine derivatives for the small molecular inhibitors of sars 3cl protease. the assay with 3cl r188i mutant protease was examined to evaluate the inhibitory activity of the synthetic serine derivatives. then, molecular docking study of complex of 3cl protease with the ligand was carried out. docking simulation experiment with r188i (pdb id: 3aw0) and the inhibitor, which has the best activity in the serine derivatives, indicated that p1 fitting s1' pocket. at the result of assay, p1, p2 and p4 positions of the inhibitor should be modified by benzoyl group, cyclohexyl group and cinnamoyl group, respectively. their bioactivities are underpinned by their distinctive structure with exceptional stability, thus making cyclotides exciting, not only for agricultural and pharmaceutical purposes, but also as a template in drug design. in all of the reported activities, cell membranes seem to be the primary target for cyclotide activity. to unravel the importance of lipid membranes on the reported activities of cyclotides, a set of cyclotides belonging to möbius and bracelet subfamilies were compared in their mode of action. the lipid selectivity and membrane affinity were compared with their efficiency against different target cells (e.g. red blood cells, bacteria, hiv particles). we have found that the bioactivity of cyclotides is dependent on the lipid composition of the target cell membrane and independent of a protein chiral receptor. in particular, all the native cyclotides tested target the cell membrane through specific binding to phospholipids containing phosphatidylethanolamine (pe)headgroups, but the membrane binding affinity is further modulated thorough non-specific peptide-lipid hydrophobic interactions, which are dependent on the specific cyclotide. in addition, the bioefficiency of cyclotides broadly correlate with their ability to target and disrupt the cell membrane. overall, we have shown that even with a common specificity for membranes containing pe-phospholipids, a fine selection was found across the family. in particular, each cyclotide inserts and disturbs the membrane in a distinct way, which explains the diversity of this family but also their distinct activities. the observation that all the tested cyclotides have a preference for a specific lipid makes this family truly intriguing and brings insights to optimize the use of the cyclotide template in drug design. malaria is a disease that affects around 500 million people causing 0.5-1 million of deaths annually. based on our previous studies, angiotensin ii (aii) presented antiplasmodial activity against plasmodium gallinaceum, but due to pressure activity, it cannot be used as an antimalarial drug. in an attempt to increase antiplasmodial activity and reduce hypertensive activity, we synthesized by solid phase method, cyclic analogues of aii with i-(i+2) and i-(i+3) lactam bridge scaffold 1 using asp and lys residues. the bridge was more effective when inserted next to n-terminal extremity 1 , probably this insertion, on another portion of the peptide, provides a change in the conformation of the molecule and its hydrophobic cluster formed by tyr, ile and his 2 , which may have influence in the peptide-membrane interaction. thus, we have focused in the n-terminal extremity, testing new analogues, using glu/asp/orn/lys residues as bridgeheads components in i-(i+4) lactam bridge scaffolds, which showed that antiplasmodial activity is increased using glu residue and that larger lactam rings are better to biologically active. therefore, new restrict peptides by i-(i+2) and i-(i+3) lactam bridge were designed, using glu residue as bridgehead element, but the same effect was not verified, getting a maximum of 65% of bioactivity. on the other hand, we promoted an increase in the hydrophobic character of the molecule, replacing the asp residue of aii sequence by fmoc-glu and asp(ofm), in order to improve the interaction of these compounds in the sporozoite membrane. the replacement by fmoc-glu provided a decrease of activity, while that asp(ofm) kept the aii activity, because there are changes of charge in the peptide, which may have modified the conformation in physiological medium. this kind of approach may offer the basis for development of new drugs and chemotherapy against malaria. animal venoms are complex chemical cocktails, comprising a wide range of biologically active reticulated peptides that target with high selectivity and efficacy a variety of membrane receptors such as ion channels or g-protein coupled receptors. venoms can therefore be seen as large natural libraries of biologically active molecules that are continuously selected and highly refined by the evolution process. the vision associated with the venomics project is to investigate in depth the enormous structural and pharmacological diversity of venom peptides through the development, integration and implementation of a novel research paradigm combining cutting-edge "omics" technologies in a high-throughput workflow. this new paradigm enclosed in venomics aims at replicating in vitro the diversity of venoms to generate original peptide banks to be used in drug discovery programs. herein, we show the different strategies we adopted for efficient solid phase synthesis and folding with an easy purification of peptides rich in cysteine and containing posttranslational modifications (ptm). angiogenesis depends on the adhesive interactions of vascular cells. the adhesion receptor integrin av b3 was identified as a marker of angiogenic vascular tissue. the αν β3 integrin receptor plays an important role in human metastasis and tumor-induced angiogenesis, mainly by interacting with matrix proteins through recognition of an arg-gly-asp (rgd) motif. inhibition of the αν β3 integrins with a cyclic rgd peptide impairs angiogenesis, growth and metastasis of solid tumours in vivo. the aim of this study was to investigate the effects of replacement of a-amino acids by aza-β 3 -amino acid analogs in cyclic rgd-peptides as αν β3 -integrin antagonist on angiogenesis, microcirculation, growth and metastasis formation of a solid tumour in vivo. the selectivity profile of these antiadhesive cyclopeptide is rationalized by a special presentation of the pharmacophoric groups. we synthesized cyclic rgd peptidomimetics that include aza-β 3 -amino acid residues. modifications were added to the rgd skeleton in order to optimize the peptide activity. then, we investigated the pharmacokinetics activity of these pseudopeptides in hek (human embryonic kidney 293) and endothelails cells huvec (human umbilical vein endothelial cells) cell by analyzing cell viability and protein involved in the angiogneisis processes. since tenascin c is a factor expressed highly in the tumorassociated matrix, targeting it would be a desirable first step for targeting the tumor-specific microenvironment in fact, a high level of tenascin c expression has been reported in most solid tumors, including lung cancer, colon cancer and glioblastoma. therefore, the targeted binding of tenascin c in tumor stroma would inhibit tumor metastasis by modulating cancer cell growth and migration. we isolated a peptide that bound to tenascin c by phage display peptide library selection, and the selected peptide specifically recognized tenascin c protein in xenograft mouse tissue. we also observed exclusive staining of tenascin c by the selected peptide in tumor patient tissues. moreover, the peptide reduced tenascin c-induced cell rounding and migration. we propose that the tenascin c targeting peptide may be useful as a specific anti-cancer diagnostic and therapeutic tool for most human solid tumors. radiolabeled pansomatostatins are expected to enhance hsst1-5 tumor-uptake and to broaden clinical indications as compared to currently established sst 2-prefering radioligands. previous experience has revealed [111in-dota 0 ,dtrp 8 ]ss-14 ([ 111 in]at2s) as a true pansomatostatin analog, exhibiting however poor in vivo stability. in order to enhance metabolic stability, we introduced a second disulfide bridge to the at2s motif by formation of extra 6/12-amino acid (aa) or 8/12-aa ring generating at5s and at6s, respectively. the orthogonally protected sequences were assembled on the solid support, deprotected and cleaved from the resin with tfa. the first cys 6 -cys 11 (at5s) or cys 5 -cys 12 (at6s) cyclization was performed in dmso, while the second was completed with iodine oxidation after in situ deprotection of cys 3 (acm) and cys 14 (acm). during hsst 1-5+-autoradiography, at5s showed unexpected total loss of sst 1-5 affinity, whereas at6s showed high affinity (ic 50 in nm) to all hsst1-5 (hsst1= 11.5±3.3; hsst2= 6.3±0.6; hsst3= 9.7±3.6; hsst4= 5.4±0.8; and hsst5= 25.7±7.0). consistent with this finding, only at6s stimulated sst2 internalization during immunofluorescence-based internalization assays, showing agonistic properties for sst2. furthermore, [111in]at6s internalized rapidly and specifically in sst2+ ar4-2j and hek293-hsst3+-cells. hplc analysis of 5 min ex-vivo mouse blood samples revealed that >98% [111in]at6s remained intact. after injection in scid mice bearing ar4-2j and hek293-hsst3+ tumors [111in]at6s specifically localized in the rsst2a+ (1.9±0.2%id/g vs. 0.8±0.05%id/g + 100 nmol tate at 4 h postinjection (pi)) and in hsst3+ implants (3.7±0.4%id/g vs. 0.3±0.05%id/g + 80 nmol ke108 at 4 h pi). this study has shown that introduction of an extra disulphide bridge in at2s confers high metabolic stability. however, in a 6/12member ring combination it leads to total loss of affinity. the reasons for this effect are currently investigated by nmr conformational studies. transporter compounds are useful tools to solubilise and increase the delivery of therapeutic molecules in the human body. one system to improve the cellular uptake of such therapeutic molecules are cell-penetrating peptides (cpps). these short peptide chains are either polycationic (containing several arg and lys) or show a more amphiphatic structure. 1 it is known that the multivalency effect -the presentation of several copies of a cpp motif on a single molecule -can increase the cellular uptake. 2 peptide dendrimers represent a group of tree-like, multivalent macromolecules, which are synthesized for different chemical and biological applications in our group. 3 we now combine linear cpps with peptide dendrimers to get a well defined branched molecule made up of only natural amino acids. in our systematic study of peptide dendrimers decorated with different cpps we found that the potency of the single cpp as a transporter for small molecules can be increased and that these peptides show usually low cytotoxicity. additionally we designed new dendritic cell penetrating peptides with similar activities like linear cpps. all compounds are covalently linked to fluorescein for visualization with flow cytometry and confocal analysis. the results show that the peptides can transport efficiently a hydrophobic cargo into the cells. chemical stability of esters of acyclovir with amino acid and cholic acids k. chuchkov, r. chayov, i. g. stankova* south-west university "neofit rilski", blagoevgrad, bulgaria amino acid esters of antiviral drugs are a very good solution for improving oral bioavailability of the actual medicine. one of the most effective and tolerant prodrugs is valine ester of acyclovir -valaciclovir. taken orally exhibits three to four times higher bioavailability of acyclovir. the chemical stability of amino acids (4-fphenylalanine) (r,s) and bile acids (deoxycholic acid and chenodeoxycholic acid) esters of acyclovir was studied in experimental conditions simulating some relevant biological medias (ph 1.0 and 7.4, 37°c).the chemical stability experiments revealed that the examined amino acid ester of acyclovir were relatively unstable in acidic ph, but bile acid ester is stable in the same ph. the examined amino acid and bile acid esters of acyclovir in neutral ph are relatively stable. in ph 7,4 all of tested compounds are more stable than valacyclovir (t1/2 = 13 h) -the first effective prodrug of acyclovir. in acidic ph acyclovirdeoxycholat and acyclovirchenodeoxycholat are more stable than valacyclovir. acyclovirchenodeoxycholat is the most promising anti-ebv prodrug candidate with high activity and satisfying chemical stability. cell-penetrating peptides (cpp) have become efficient tools for the cellular internalization of bioactive molecules due to their ability to cross the plasma membrane of diverse cells and cell lines. [1] we recently reported that the cpp sc18, which consists of the residues 106-121 of the c-terminal region of the cationic antimicrobial peptide cathelicidin (cap18), is an effective carrier peptide for small organic molecules like fluorophors and toxic peptide sequences into various cell lines [2] . however, in general linear peptides are more susceptible to proteolytic degradation than their cyclic analogs [3] . therefore, we investigated the cyclization of cpp derived from sc18 by means of cui-mediated azidealkyne cycloaddition (cuaac) [4] . furthermore, we examined their conformation and proteolytic stability as well as their internalization efficiency and toxicity against various cell lines, in comparison to their linear equivalent and to other cpp. looking for the proper prodrug: a peptidomimetic approach to identify and inactivate bacterial mono-adp-ribosyltransferase toxins m. beich-frandsen, r. jørgensen division of microbiology and diagnostics, statens serum institute, copenhagen, denmark mono-adp-ribosylation is an endogenous posttranslational modification in eukaryotic cells, simultaneously utilized as virulence strategy by deadly secreted bacterial toxins. many bacterial toxins have been found to act as mono-adp-ribosylating enzymes, targeting anything from g-proteins to the actin skeleton. the diphtheria toxin from c. diphtheriae and exotoxin a from p. aeruginosa, both target the diphthamide-group of a unique modified histidine in eef2, inhibiting protein synthesis by ribosome mimicry 1,2 . we aim to inactivate these nad+-utilizing toxin enzymes by nad-conjugated peptidomimetics, in a target-specific prodrug-approach. the adp-ribosylation reaction follows a random third-order s n 1 mechanism. in the proposed model for the transition state of the reaction, the cleavage of the n c1-nn1 bond of nad + releases strain and generates a oxacarbenium ion intermediate with a positively charged nicotinamide (n)ribose, subject to a nucleophilic attack from the substrate 3,4,5 . adp-ribosylating toxins are commonly characterized by a artt-motif involved in substrate recognition 2 . studies suggests conformational rearrangement of the residues surrounding the substrate binding site to be required for optimal geometry 5 of the initial glycosidic nc1-nn1 bond cleavage within nad + . subtype specific nad-conjugated peptides, designed based on previous structural analysis of the adpribosylation reaction, act as substrate for the enzymatic adp-ribosyl-transfer, and hereby attach covalently to and inactivate the nad + -utilizing toxin. relying on previous structural studies, and established ligand-binding and kinetic data, an initial peptide library, designed by bioinformatics and evaluated for specificity of common targets in-silico identifies initial leads. lead-scaffolds are implemented in rational peptide-design, based on high-resolution structural-and biophysical studies of multiple peptide-enzyme complexes, to identify possible prodrug-strategies for enzyme inactivation. nanoparticles play a crucial role in medicine for their potential application as in vivo carriers of active principles [1] . liposome display unique pharmacokinetic properties slowly releasing drugs loaded in the inner aqueous cavity. in the last years we have developed supramolecular aggregates labeled by bioactive peptides able to recognize overexpressed receptors on tumour cells membrane delivering doxorubicin chemiotherapeutic drug [2] . neurotensin(nt), a 13 amino acid peptide, has dual functions of neurotransmitter or neuromodulator. the cterminus short fragment 8-13 preserve the activity but the half life of wild type form in vivo is very short. nt receptor type 1 (nts1) is overexpressed in severe malignancies such as small cell lung cancer and colon, pancreatic, and prostate carcinomas. we have designed new amphiphilic molecules containing in the hydrophobic moiety two aliphatic chains and in the hydrophilic moiety a the bioactive portion able to aggregates with phospholipid molecules achieving liposome. we have synthesized neurotensin wild type sequence, the truncated form and the tetra-branched neurotensin(nt1-13) or a truncated form(nt8-13) tetrabranched peptides(nt4) adopting an opportune synthetic strategy on solid phase. all liposome were formulated adding the neurotensin amphiphilic monomer in ratio 5:95 with dopc in order to evaluate the capability to recognize selectively receptors overexpress on cell membrane surface. the liposomes size was determined by dynamic light scattering measurements, values for the hydrodynamic radius(rh). the selective internalization and cytotoxicity of fully doxorubicin loaded liposomes as compared to pure dopc liposomes, was tested in ht29 human colon adenocarcinoma and te671 human rhabdomyosarcoma cells. recently, small interfering rna (sirna), one kind of rna interference (rnai) technology represent the most common and, to date, the most effective method to inhibit target gene expression in human cells. it is also a common recognition that non-toxic delivery of sirna is an urgent problem for the therapeutic application of sirna. for the efficient gene silencing in vivo, prolonged circulation of sirna with take efficient and non-toxic cellular uptake and resistance against enzymatic degradation are indispensably required. 1 ) telomerase activity has been regarded as a critical step in cellular immortalization and carcinogenesis and because of this, regulation of telomerase represents an attractive target for anti-tumor specific therapeutics. in this paper, we present the efficient and non-toxic cellular uptake of sirna using novel amphiphilic peptides and the application to silencing of htert in human cancer cell lines. in the present study, we investigated the intracellular delivery of sirna using some amphiphilic peptides and the silencing effect of sirna targeting htert mrna in 3 human cancer cell lines, jurkat, hela and k562. the complex of sirna and a specific amphiphilic peptide or its hybrid with an intracellular transport signal peptide could be effectively taken up into cells. the complex also showed a high silencing effect against htert mrna. moreover, the combination of sirna-nes conjugates and the amphiphilic peptides improved silencing effects up to 95.2 %. the amphiphilic peptides and their hybrids showed almost no cyto-toxicity and protected sirna against intracellular nuclease digestion in 10% fbs (half life time was over 48h). tumor targeting with the decapeptide gonadotropinreleasing hormone (gnrh) or its analogues is based on the discovery that gnrh receptors are overexpressed in many tumor cells, compared with their expression in normal tissues. using these peptides as carriers/targeting moieties in a conjugate with therapeutic agents can increase the selectivity and the stability of the conjugates, or eliminate the toxic side effects of the drug. gnrh-iii (75% labeling efficiency) as determined by hplc analysis. tc-99m-rh-ang ii exhibited good chemical stability against cysteine transchelation and sufficient metabolic stability in human plasma. in mice, the bioconjugate displayed efficient clearance from the blood and excreted mainly through the renal route with some excretion by the hepatobiliary pathway. the uptake in the heart was 1.8±0.5% id/g as early as 30 min post-injection; whereas, the uptake in the lungs, liver, stomach and kidneys varied between 1-10% id/g. in rats, the bioconjugate displayed relatively better pharmacokinetic characteristics, with low uptake in the major organs (<4% id/g). the uptake in the heart (1.7±0.4% id/g) was found to be higher than the uptake in the blood and muscle, resulting in good heart-to-blood and heart-to-muscle uptake ratios. this initial study towards the development of an effective cardiac imaging agent advocates that the use of hybrid conjugates appears to hold a great promise as a new and attractive approach for rapid and efficient imaging of heart. in humans two isoforms of gnrh are exist, gnrh-i (30% are obtained in first attempts and stepwise formation of the disulfide bridges is performed within a few hours instead of days. in recent thirty years, c-terminal modified peptides have been proved to have greater potential as apis (active pharmaceutical ingredients) due to their increased chemical and enzymatic stability and improved pharmacodynamic properties 2-4 . a prominent example, octreotide 5-6 , an octapeptidoalcohol, has witnessed as a potent anti-cancer agent targeted for gastro-entero carcinomas. in view of synthetic methodology, peptidoalcohol can not be directly prepared by standard spps protocol becouse of the c-terminal structure released from resin are not alcohol but always peptidoacid or peptidoamide. to overcome this problem, a novel protocol of shortened n-1 coupling cycles on merrifield resin and then the ammonolysis of peptedyl resin by an aminoalcohol as the c-terminal residue getting peptido-alcohol as targetting product has been devoloped in our lab. because of the cleavage treatment of peptidyl merrifield resin is not under acidic condition, such as hf or tfmsa, but ammonolysis, some side-chain producting groups(spg) related to boc chemistry like bzl, clz, tos…; must be avoided in sequence assembly. therefore a hybrid orthogonal protection (hop) of boc/fmoc protocol was adopted for the sake of producing naked peptidyl (without any spg) resin before ammonolysis. fifteen peptidoalcohols with different terminal alcohols were conveniently prepared, most of them released form resin with very good yields. due to its cyclic structure, proline is the coded amino acid with a more restricted conformational flexibility. the incorporation of additional groups into the pyrrolidine ring is a useful means to produce new amino acids that combine the conformational properties of proline with sidechain functionality. this is the case of β-phenylproline, (βph)pro, that can be regarded as a proline-phenylalanine hybrid in which the orientation of the aromatic substituent is dictated by the conformation of the five-membered ring and the cis or trans configuration of the phenyl group relative to the carbonyl moiety. accordingly, cis(βph)pro and trans(βph)pro combine the conformational properties of proline with an aromatic side-chain functionality that is rigidly oriented with respect to the peptide backbone, and this may be useful in the design of biologically active peptides and other applications relying on specificallyoriented side-chain moieties. we have developed synthetic procedures for the preparation of the cis(βph)pro and trans(βph)pro stereoisomers in enantiomerically pure form. the methodology is based on the preparation of racemic precursors of each amino acid and their subsequent hplc resolution on chiral columns. multigram quantities of the target amino acids have been isolated in optically pure form and suitably protected for use in peptide synthesis. the importance of peptide cyclization for studying peptide conformation, creating new structures, or for developing peptide therapeutics is well established. in particular, sidechain lactam bridges linking two amino acid residues that are several residues apart in the linear sequence or headto-tail backbone peptide cyclization enable rigidification of the structure and improvement of in vivo stability. native chemical ligation (ncl) is now an established method for producing backbone-cyclized peptides or proteins. the application of ncl to the synthesis of sidechain cyclized peptides is less frequent. head-to-side-chain cyclization by ligating a c-terminal thioester with a cys residue located on a lysine side-chain was used by few authors. the alternative tail-to-side-chain cyclization mode is rare, probably due to the difficulty of installing a thioester group on amino acid side-chains such as aspartic or glutamic acids the reaction of a bis(2-sulfanylethyl)amido (sea on ) group with an n-terminal cysteine residue in water and at neutral ph results in the formation of a native peptide bond. [1] oxidation of sea on results in a cyclic disulfide called sea off having a 1,2,5-dithiazepan-5-carbonyl structure. [2] sea off is a self-protected form of sea on . we show here that bis(2-sulfanylethyl)amido side-chain acid(dab), ornithine and lysine were selected as building block; 1a and n,n'-cbz-1-amidinopyrazole (1b) were selected as guanidinylating reagents for specific situation. for synthesis of n-terminus local cyclo-guanidine peptide, designated peptides were assembled on acid labile solid support such as rink amide resin by fmoc strategy. then either fmoc-dab(boc)-oh, fmoc-orn(boc)-oh or fmoc-lys(boc)-oh was incorporated respectively at n-terminus. fmoc was removed followed by guanidinylating by 1b and then peptide was cleaved by acid. by neutralizing with nmm in acetonitrile solution, side chain amino group and a-guanidine would form 6, 7 or 8 membered local cycloguanidine. the remaining cbz could be removed by hydrogenation. for synthesis of backbone side chain cyclic peptide, bis-fmoc-daa was introduced in the peptide previously on resin followed by removal of fmoc. selective guanidinylate side chain aminogroup by 1a followed by peptide assembling with an insertion of orthogonal protected daa at 1-4 aa apart from first daa. for synthesis of a-nh2sidechain cyclic peptide, first daa should be introduced with orthogonal protected form. 1b was used to guanidinylate a-nh2. after cleavage and neutralization of those two kinds of intermediates, guanidine-bridged marco-cyclic peptide was formed. the resin is also a multipurpose tool for the synthesis of carboxylic acids, esters and thioesters. when the synthesis is completed, the fully protected peptide hydrazide resin is oxidized with either n-bromosuccinimide (nbs) or copper(ii) acetate in pyridine. the resulting acyl diazene resin is then cleaved by peptide displacement at the c-terminus with amine. the fully deprotected peptide amide is finally obtained by treatment with trifluoroacetic acid (tfa). in our approach, we used a 4-fmoc-hydrazinobenzoyl am novagel resin to synthesize a peptide-substituted amide in the c-terminus. first, the oxidative cleavage was carried out with nbs in pyridine and a nucleophile [a protected 4 (aminomethyl) benzimidamide (amba)]. however, the yield of the reaction was very poor. in the next step, we applied copper(ii) acetate in the presence of pyridine and amba. following optimization, the efficiency of the process was significantly improved. herein we discuss the conditions needed to obtain a reasonably high efficiency of the oxidative cleavage in the synthesis of our c-terminal modified peptides using the aryl hydrazine resin linker. blood vessels on tumor tissues, similarly to integrin receptors. this observation suggests cd13 as a selective target for targeted delivery of drugs and nanoparticles to tumor neovasculature using ngr peptides as homing motif. in our work, new cyclic-ngr peptides containing a thioether linkage were prepared. the influence of their structure on the speed of succinimide ring formation and deamidation was evaluated and compared with the previously published data on cyclic-ngr derivatives containing amide bond or disulfide bridge in the cycle (c[kngre]-nh2 and c[cngrc]-nh 2 ). to avoid the deamidation under the conditions used for cyclization, the synthetic routes were optimized. the influence of the ph, ionic strength and temperature of the solution on their chemical stability was investigated. the structure of the cyclic peptides was investigated by circular dichroismand nmr-spectroscopy. receptor binding ability and the influence of the cyclic peptides on the cell adhesion and motility were also evaluated. this work was supported by grants from the hungarian national science fund (otka nk 77485 and k 81596) and the national innovation office (bio_surf, om-00146/2008). clickable peptides and their attachment to oligonucleotides m. wenska, m. alvira, r. strömberg department of biosciences and nutrition, karolinska institutet, novum, se-141 83 huddinge methodology for the ready conversion of peptides into "clickable" azido-peptides with the possibility of selecting either n-terminus or c-terminus connection is presented. 1 synthesis of peptide-oligonucleotide conjugates (poc's) include conjugates of oligonucleotides with peptides known to be membrane penetrating and nuclear localization signals. a general procedure, based on a new activated alkyne linker, for the preparation of poc's has been developed. 2 with this linker, conjugation is effective at room temperature in mm concentration and submicromolar amounts. this is made possible since the use of a readily attachable activated triple bond linker speeds up the cu(i) catalyzed 1,3-dipolar cycloaddition ("click" reaction). the main scheme for conjugate preparation involves sequential conjugation to oligonucleotides on solid support of i) an h-phosphonate based aminolinker ii) the triple bond donor p-(npropynoylamino)toluic acid (pata) and iii) azido-functionalized peptides. the method gives excellent conversion of oligonucleotide to the poc on solid support, and only involves a single purification step after complete assembly. the procedure which makes use of a low concentration of copper ions leads to a product with very little copper left (similar or less than in drinking water). the synthesis is flexible and can be carried out in non-specialist laboratories without the need for specific automated synthesizers since it has been designed to utilize commercially available oligonucleotide and peptide derivatives on solid support or in solution. comparison of alternative deprotection reagents to piperidine for the synthesis of a poly-alanine peptide on the tribute® peptide synthesizer m.a. onaiyekan,* j.p. cain, c.a. chantell, m. menakuru protein technologies, inc. tucson, az, usa in peptide synthesis, piperidine is a common agent for fmoc removal. however, piperidine is a controlled substance which requires special handling and cannot be used in some countries. therefore, it would be useful to identify alternative deprotection reagents to piperidine for fmoc removal. it is well known that poly-alanine sequences have a high propensity to aggregate after the fifth residue. in this application, (a)10k-oh was synthesized using the tribute®'s intellisynth uvmonitoring and feedback system to compare the efficiency of fmoc removal by piperidine vs. three alternative bases (pyrrolidine, cyclohexylamine, and tertbutylamine) in the last 5 cycles of the synthesis. it was found that pyrrolidine produced a higher purity product with fewer deprotection repeats and shorter deprotection times per cycle than piperidine, proving it to be a highly efficient, viable alternative to piperidine for fmoc removal. the endogenous tripeptide gpe also nammed "glypromate" is made up by the three n-terminal residues (glycine-proline-glutamate) of the insulin-like growth factor 1 (igf1). this tripeptide is a partial glutamate antagonist and showed good results in different neuroprotective in vitro and in vivo experiments. 1,2 gpe also binds to glial cells regulating neurotransmitter levels in the brain. 3, 4 however, gpe suffers from poor lipophilicity and a short half-life in vivo. that's why there is a need for more lipophilic and protease resistant analogues of gpe. in this poster we present the synthesis of trifluoromethylated analogues of gpe based on the 2 or 5-cf3-pseudoproline residues. introduction of fluorine atoms on bioactive compounds is known to deeply modify their physico and biochemical properties increasing lipophilicity and resistance to protease. 5 thus, developing a trifluoromethylated analogues, we intend to increase the bioavailability of gpe, keeping the benefit of its neuroprotective properties. our research team is strongly involved in the synthesis of trifluoromethylated alpha-amino acids. recently we published the synthesis of 2-trifluoromethyl-1,3oxazolidines derived from fluoral and (l)-serine and we demonstrated that these five membered ring 5-cf3pseudoprolines are hydrolytically stable and can be considered as proline analogues. 6 that's the reasons why we are interested to replace the proline residue of gpe by those trifluoromethylated compounds. the development of original coupling conditions and the detailed synthesis of two pseudoprolines analogues of gpe will be presented in this poster. modifications. in combination with automated spps, unprecedented access to large peptides and small proteins for biological research has been achieved. we demonstrate the application of this methodology to the synthesis of a variety of peptides on the prelude® peptide synthesizer. exploring the space of fluorine-labeled α-amino acids for solid state 19 f-nmr structure analysis of peptides: rational design, synthesis and applications p. solid state 19 f-nmr is a powerful method to study membrane-active peptides, as it can reveal their conformation, orientation and dynamics when embedded in biomembranes. 1 for this purpose the native peptide has to be selectively labeled with a suitable 19 f-containing amino acid at several different positions. the resulting battery of singly 19 f-labeled analogues is then analyzed by solid state 19 f-nmr. the main limitation to this approach currently lies in the poor arsenal of available 19 f-labels. we have therefore rationally designed and synthesized several specific amino acids bearing a cf3-reporter group, which fulfil all strict criteria to a "proper" 19 f-label. 2, 3 to allow a geometry-based structure calculation, the cf3group has to be rigidly attached to the peptide backbone. we thus rigidified the side chain using either a [1.1.1]bicyclopentane moiety, a cyclobutane ring, or the intrinsic proline framework. this way, suitable cf3-labeled analogues were created as substitutes for bulky hydrophobic amino acids (leu/ile/val/met), for aromatic residues (phe), for polar side chains (ser/thr), and for proline (pro). by now we have applied the developed 19 f-labels for a comprehensive structure analysis of more than ten different membrane-active peptides (gramicidin s, pgla, mag 2, kigaki, sap, temporin a, bp100, etc). recently, several new activators have been introduced into the market, and they were evaluated along with some older activators for their ability to synthesize a range of peptides with shorter and longer reaction times on the symphony® peptide synthesizer. it was found that hdmc, pyclock, comu, hctu, and hatu worked well at shorter reaction times (2x1 min), but pyoxim and tffh only worked well at longer reaction times. the performance of pybop at shorter reaction times was poor only for more difficult sequences. these results are important for selecting an appropriate activator for fast spps applications. the plant cyclotides form the largest family of cyclic peptides 1 . they contain a signature motif referred to as the cyclic cystine knot, which is derived from the cyclic backbone and three inter-knotted disulfide bonds. intriguingly, cyclotides can be boiled, treated with chemicals or enzymes without disrupting their overall fold. thus, they are sometimes labeled as ultra-stable proteins. in addition, cyclotides are tolerant to mutations, and as a scaffold they can successfully accommodate foreign bioactive epitopes of variable sequences 2 . cyclotides share many of these properties with another disulfide containing cyclic plant peptide, the sunflower trypsin inhibitor 1 (sfti-1) 3 . emerging evidence indicates that cyclotides and sfti-1 are valuable not only as peptide stabilizing scaffolds; in combination with their cell penetrating properties, these disulfide rich cyclic peptides have significance as intracellular drug carriers. although both peptides are genetically encoded, studies to ascertain the exact mechanisms of their biosynthesis are currently on going. thus, the synthesis of cyclotides and sfti-1 are currently restricted to chemical means. we have recently adapted a fmoc-spps method for cyclic peptide synthesis, via n-acylurea intermediates with the assistance of microwave irradiation. this method is a safe and convenient alternative to boc-spps and has the ability to be automated conveniently. using this method, parent scaffolds as well as several cyclotide and sfti-1 analogues with potential antimicrobial and matrix metalloprotease activities were synthesized. with the rising interest in the cyclization concept as a tool to impart stability on unstable peptides, the cyclic peptide synthesis method adapted herein is anticipated to have numerous applications. fixed configuration. the nonnatural oligomers have an extended conformational space and are supposed to adopt non-canonical secondary structures 2 . in addition, the backbone modification makes these molecules more stable towards proteolytic degradation. the majority of proteins in nature are post-translationally modified, and the most abundant modification is the protein glycolysation, which introduces wide structural variety to proteins. glycoproteins have an important role in the biological recognition process, such as immunodifferentiation, cell adhesion, cell differenciation and regulation cell growth 3 . new aza-β 3 -amino acids bearing either an azide instead of amine on lys and orn chain or an alkyne group will be described and used in solid phase synthesis to finally performed a click chemistry to cyclize pseudopeptides or to introduced a glycosylated function 4 . true for a series of peptides that display strong corticotropin releasing factor (crf) antagonistic activity. seminal studies by rivier et al. have shown that the incorporation of a lactam bridge in the crf-sequence resulted in an enormous increase in activity and potency, due to stabilization of the bioactive a-helical conformation of the peptide; and the newly designed peptide was called astressin. 1 based on the astressin sequence, we started a truncation and deletion study to arrive at astressin analogs with a reduced size but still remain active as crf antagonists. this study resulted in the smallest active crf antagonist, astressin(30-41). 2 this sequence was further optimized by the introduction of novel covalent constraints, other than the well-known lactam bridge. as a first approach, the alkene/alkane bridge, which can be introduced via ring-closing metathesis via alkenesubstituted amino acid side chains, and as a second approach, the triazole bridge ('click' macrocyclization), via either a cu(i)-or a ru(ii)-catalyzed cycloaddition reaction between azide-and alkyne-derivatized amino acid residues were explored. herein, we will present the details of the synthesis of the alkene-, azide-, and alkyne-functionalized amino acids, their use in spps, and the optimized approaches for macrocyclization. furthermore, the peptides have been characterized by hplc, nmr, lcms, and studied by circular dichroism spectroscopy to obtain insight into the helical propensity of the peptides in relation to the cyclic constraint. the synthesis of a nitronyl nitroxide, c α -tetrasubstituted αamino acid (a class of sterically restricted amino acids that promote the formation of peptide β-turns and helical structures) was achieved by derivatisation of racemic 2amino-5-cyano-indan-2 carboxylic acid [aic(cn)]. racemic boc-aic(nn)-oh was prepared by bis(alkylation) of ethyl isocyanoacetate under phase transfer conditions with 3,4-(bis)bromomethyl benzonitrile as alkylating agent, followed by acidic hydrolysis, n α -boc protection, and saponification of the ester function. resolution was achieved through formation of the diastereomeric amides of (s)-phenylglycinol with chromatographic separation and mild acidic hydrolysis. reduction of the nitrile group to an aldehyde was carried out with raney nickel in the presence of sodium hypophosphite. condensation with 2,3-diamino-2,3-dimethylbutane gave the corresponding tetramethylimidazolidine, which was oxidised with 3chloroperbenzoic acid to the desired nitronyl nitroxide. the uv-vis absorption and epr spectra of the amino acid were recorded and its magnetic properties were examined. in order to develop the synthesis of this peptide using the fmoc solid-phase peptide synthetic methodology, orthogonally protected β-hydroxyaspartic acid was needed. more precisely we wish to dispose of (2r,3r)-n -fmoc-3-tbdm-silyloxy-aspartic acid α -allyl ester instead of the recently reported dmab ester 2-3 indeed, in preliminary assay using this protective group we experienced difficulties during the final cyclisation step 4 . the synthesis was developed starting from inexpensive l(+) dimethyltartrate and extended to the others stereoisomers of the β-hydroxyaspartic acid. structure. for that, we chose to replace proline by silaproline to afford polysilaproline. this study shows the comparison of two polyamino acids: polyproline and polysilaproline polymers. homopolypeptides were synthesized by polymerization of corresponding amino acid n-carboxyanhydride 3 . multicomponent reactions (mcrs) represent a chemical process involving at least three reactants for the formation of several covalent bonds in one operation 1 . by definition mcrs are chemo-and regioselective, convergent stepefficient procedures and take place with high atom economy. the copper(i)-catalyzed 1,3-dipolar cycloaddition of organic azides and terminal alkynes (cuaac) reported by meldal 2 and sharpless3 has been involved in various fields of chemistry and biochemistry research. however only few reports describe the implementation of cuaac and mcrs. 4, 5 recently our research focused on a novel threecomponent reaction based on a cu(ii)-triggered aminolysis of peptide hydrazide resin and an azide-alkyne cycloaddition sequence. 6 copper(ii)-induced oxidative aminolysis of hydrazides generates cu(i), catalyst of the azide-alkyne cycloaddition. this feature was exploited to design a solid phase detaching three-component reaction. the mcr process requires a peptide hydrazide resin, an amino azide linker and an alkyne, resulting in the formation of peptide modified at the c-terminus through an amino 1,2,3-triazole linker. this method can potentially be applied to the synthesis of a large variety of peptide derivatives starting from fmoc-spps assembled peptidyl resins. furthermore, it is not practical to compare hplc spectra from different resin samples (e.g., before and after reaction) directly. a comparison by analyzing the same (mg) amount of resin would involve tedious sample preparation that is extremely error-prone and would be impractical because factors resulting from the increase or decrease of the molecular weight of the resin-bound compounds may have a significant influence on the results. the use of internal reference compounds allows rapid assessment of reactions performed on solid supports. the internal reference compound is bound to the resin together with the substrate and cleaved with the products after completion of the reaction. commercially available compounds can be used for this purpose, or likewise, the reference compound can be generated from the substrate by partial capping of a functionality. the peak integration of the reference compound in the hplc-uv spectra can be correlated directly to those of the rest of the compounds present in the reaction mixture and therefore a quantitative interpretation of the spectra with respect to conversion and yield is possible. here we demonstrate the proof of principle as well as the accuracy of this method. modifier proteins such as ubiquitin are conjugated to protein substrates in cells and thereby mediate various biological processes. 1 of high interest, is the ubiquitin fold modifer 1 (ufm1, 83 residues) which has structural similarity to ubiquitin but has no sequence similarity. unlike ubiquitin, ufm1 has not been extensively studied and little is known about its biological role. to understand ufm1's biological functions, access to pure, homogeneous natural and modified ufm1 protein is essential. chemoselective ligation techniques are suitable for providing such proteins. recently, a variation of the α-ketoacid-hydroxylamine (kaha) ligation 2 was developed, which utilizes the chemoselective reaction between a c-terminal peptide αketoacid and a n-terminal 5-oxaproline. 3 this modified form of the kaha ligation furnishes a native peptide bond and a homoserine residue. this ligation is useful for the synthesis of proteins from two unprotected protein segments in aqueous buffers. for the synthesis of larger proteins, a sequential ligation strategy is necessary. using ufm1 as the model system we have developed a sequential ligation procedure using kaha ligation with 5-oxaproline. applying the new sequential ligation strategy we have prepared ufm1 by total chemical synthesis. we have also prepared a cterminal thioester surrogate of ufm1 protein, which is suitable for conjugation to proteins of interest. the syntheses required the development of a bifunctional peptide segment bearing an α-ketoacid and an orthogonally protected 5-oxaproline. the preparation of the protein segments, their intermediates, the deprotection, and sequential kaha ligations towards the syntheses of ufm1 protein and c-terminal modified thioester ufm1 protein will be discussed. affinity and biological activity, we have designed and synthesized new analogues by multiple n-methylation of hut-ii(4-11) backbone amide bonds. all the peptides were performed by a novel synthetic approach, in which the introduction of n-methyl groups occur during regular solidphase peptide synthesis. on these new ligands we evaluated the binding affinity and biological activity at the ut receptor and performed preliminary nmr conformational studies. since that time a number of different machines have been used to automate peptide synthesis. modern machines are following two general setups; the so called "single approach" and the "parallel approach". in the single approach, the machine is developed to synthesize one or few peptides simultaneously. the user is able to optimize the synthesis conditions on each single peptide and each single coupling step. the maximum product quality regarding purity and yield is the major task of this approach. in the parallel approach, the machine is developed to synthesize a huge number of different peptides in the same single setup and time-frame. the user always has to find a synthesis protocol appropriate for the needs of each peptide to reach the maximum quality, knowing that there will be always a number of failed peptides. as a result you will find both types of peptide synthesizers in laboratories all over the world: the single machine, for the complicated peptides, and the parallel machine, allowing generation of multiple peptides with standardized protocols for each. the tetras is the first instrument combining the advantages of both machine types and allows the user to synthesize up to 106 different peptides in parallel. each peptide can have its own individual synthesis protocols, separate of all others. the user can combine different synthesis scales, peptide lengths, and activator reagents in one run. finished peptides can be removed and new peptides can be started while the tetras is still running. the tetras allows the user to establish an uninterrupted production shop using one instrument only. siemion, i. z.; peptide res the peptides: analysis, synthesis and biology monitoring peptide folding in membrane-active peptides: a time-resolved spectroscopic study e. gatto a cordopatis p. 31st european peptide symposium sar studies of triazolyl-containing cyclopeptides: a defined -turn structure increases potency and selectivity to melanocortin receptor subtypes c. testa, a,b proc. natl. acad. sci proc. natl. acad. sci usa multicomponent reactions microglobulin: a "difficult" protein s. abel, m. beyermann 1 the protein ß2-microglobulin constitutes the noncovalently bound light chain of the major histocompatibility complex class i (mhc) and plays an essential role in the dialysisrelated amyloidosis. [1, 2] to examine the amyloid fibrils of the ß2-microglobulin (ß2-m) via infrared spectroscopy we intended to synthesize 13-c-labeled ß2-m. [3] due to the two cysteine residues in positions 25 and 80 we used the native chemical ligation (ncl) strategy for assembling the 99-mer protein. this necessitates the synthesis of three segments which was accomplished on solid phase using the fmoc/t-bu chemistry. the preparation of the segments had to be optimized with respect to aggregation, aspartimide and piperidide formation, trifluoracetylation, and s-tert-butylsulfonium formation. additionally, ncl steps had to be optimized, because of "internal" thioester formation, dimerization and the formation of side-products of the activated n-terminal segment peptaderm inc., krakowskie przedmie cie str. 13, warsaw, poland immunosuppressors, such as cyclosporine a (csa) and tacrolimus®, are routinely used in prevention of graft rejection after organ transplantation and in therapy of some autoimmune diseases, including skin inflammation. a naturally occurring in linseed oil cyclolinopeptide a (cla, c(-pro-pro-phe-phe-leu-ile-ile-leu-val) 1 possesses a strong immuno-suppressive activity, comparable at low doses with that of csa 2 , but is much less toxic. we synthesized new cla analogs, containing instead of one proline residue its six-membered mimics, pipecolic acid (pip): c(-pip-pro-phe-phe-leu-ile-ile-leu-val) (1) and c(-pro-pip-phe-phe-leu-ile-ile-leu-val) (2). the incorporation of pipecolic acid residue led to different conformational behavior of the nonapeptide cycle. nmr experiments in cdcl 3 solution showed that cla analogue 1 with the pipecolic acid residue in position 1 was much more flexible than cyclopeptide 2. the new peptides were devoid of toxicity up to 100μg/ml with regard to human peripheral blood mononuclear cells (pbmc), did not inhibit tumor necrosis factor alpha production in blood cell culture, but exhibited dosedependent, anti-proliferative actions for phytohemagglutinin a-activated pbmc. since peptide 1 was more potent it was tested for growth inhibition of l-1210 lymphatic leukemia. the peptide was found to strongly inhibit the cell growth even at low concentration (63% inhibition at 5μg/ml). hiv-1 has emerged as the largest and the most devastating public pandemic in our days, affecting approximately 70 million people worldwide 1 . development of an effective, safe and preventive hiv vaccine remains an urgently needed priority. epitopes for hiv-specific antibodies in elite controllers, a subgroup of long term non progressors, encompassing segments of mper of gp41 and for the v3 loop of gp120 were identified using the phage display technology 2 . immunization experiments with epitopes conjugated to an artificial sequential oligopeptide carrier (soc4), formed by four repeats of the tripeptide lys-aib-gly in tandem, or to the palmitoyl group are currently in progress. all syntheses were performed on a rink amide resin following the fmoc technology. conjugation of epitopes to the soc4 carrier was realized via a chemoselective ligation approach, which generates an oxime bond between the h2n-o-groups of the modified lysine residues and the aldehyde group of each epitope 3 institute of immunology and experimental therapy, polish academy of sciences, 53-114 wrocław, poland 4 peptaderm inc., krakowskie przedmieście 13, 00-071 warszawa, poland nonproteinogenic amino acids have been a tool to modify the structures of natural peptides since a long time 1 . bioactive peptides involved in a physiological and biochemical processes cannot be applied in the therapy because of their instability in physiological conditions. that's why the synthesis of their stable active analogues is a challenge for medicinal chemistry nowadays. 4-trans-hydroxyproline (hyp) is an important building block of natural collagen. it is responsible for the stabilization of collagen super helix, forcing the trans amide bonds configuration with preceding amino acids 2 . at the same time the impact of trans-4-hydroxyproline on the conformation other than the collagen peptide chains of biologically important compounds is little known. it is known that immunosuppressive activity of cla is comparable with cyclosporine a and is associated with the presence of the tetrapeptide fragment pro-pro-phe-phe containing pro-pro cis amide bond. 3 now we present synthesis, conformation and biological activity of new analogues of cyclolinopeptide a (cla), containing 4-transhydroxyproline instead of proline residues in position 6 or 7. we expected that the introduction of the hydroxyl group in the pyrrolidine ring might influence the biological activity and conformation of the native peptide due to its hydrophilic character and hydrogen bonding ability. the linear precursors of modified cla analogues were prepared manually by standard solid-phase procedure "step by step" on wang resin using fmoc/tbu strategy and tbtu as coupling reagent. the cyclizations of linear peptides have been made under high dilution conditions by means of edc/hobt coupling reagents. the biological activity of newly synthesized compounds as well as the conformational study will be evaluated. dip. di scienze ambientali, seconda università di napoli, caserta, italy nmr spectroscopy is a powerful method to perform structural studies on peptides. to completely fulfill the potential of nmr, peptides labeled with stable isotopes ( 15 n, 13 c, 2 h) are essential. 1 peptides are easily prepared on solid-phase but chemical synthesis becomes prohibitively expensive when applied to the incorporation of isotopes. an alternative cost-effective strategy is the recombinant expression of peptides in e. coli as fusion constructs with carrier proteins. 2 the main problem of this approach is the need of chemical reagents or proteases to cleave the target peptide from its fusion partner after purification. proteases may determine the heritage of extrasequence amino acids at the peptide n-or c-terminus, while chemical reagents require harsh reaction condition that may modify target peptides. an interesting solution is represented by the use of inteins as fusion partner. inteins are protein elements that can catalyze their self-excision from a flanking sequences in mild conditions, by adding nucleophilic agents such as thiols or simply by shift of ph and temperature, bypassing the use of proteases or chemical reagents. 3 we used the self-cleaving mxegyra mini-intein as fusion partner for the preparation by recombinant means of two isotope labeled peptides, hplw and qk. 4, 5 the two peptides target vascular endothelial growth factor receptor (vegfr) and have been described to modulate vegf-dependent angiogenesis. our expression and purification scheme allows to obtain homogeneously isotope labeled peptides. the availability of isotope labeled hplw and qk opens the way to nmr studies aimed to characterize the folding dynamics of the two peptides and their structures in complex with vegfr. an nmr method to discriminate between the fullyextended and different helical conformations in a spacer peptide c. peggion*, m. crisma, f. formaggio, c. toniolo icb, padova unit, cnr, department of chemistry, university of padova, 35131 padova, italy the ideal fully-extended, α-peptide conformation, also known as 2.05-helix, is characterized by φ = ψ = ω = 180°t orsion angles. the repeating motif of this foldamer is a pentagonal (pseudo)cyclic structure (called c5), stabilized by an intraresidue h-bond. the n-h and c=o groups in the 2.05-helix are not involved in intermolecular h-bonds. multiple c5 conformations were observed in homopeptides made up of c α,α -dialkylated glycines with both side chains longer than a methyl. this is the case for c α,αdiethylglycine (deg), the residue studied in this work. it is known that deg homo-peptides can adopt the 2.05-helix 1 or the 310-helix depending on environmental factors and nand/or c-terminal moieties. 2, 3 in this communication, we introduce an nmr method to discriminate between the 2.05-helix and the 310-helix based on the observation of cross-peak intensities in the noesy human serum amyloid a (saa) is a highly conserved apolipoprotein produced by the liver under inflammatory conditions accompanying e.g. atherosclerosis, cancer and amyloidosis [1] . it is also known that saa1α isoform has the amyloidogenic properties [2] . till now it is little known about structure of human saa, as it hampers structural studies due to its facile aggregation. the analysis of protein sequence and cd data together with theoretical studies revealed a typical globular structure of the protein [3] . the c-terminal sequence of saa contains three proline residues, which probably are responsible for the unordered structure. recent in vitro studies involving saa and human cystatin c (hcc) revealed direct interactions between the (86-104) fragment of saa and the (93-120) sequence of hcc. the results of elisa test for the (86-104) saa fragment have shown that it binds to hcc very well. the nmr studies for the wild (86-104) sequence found an unordered structure in phosphate buffer. based on these data we decided to check how the point mutations pro→ala in (86-104) saa fragment could influence the peptide's structures. we synthesized four peptides with pro→ala point mutations and we performed cd experiments at different conditions. the results show that two of them contain disordered structure and two α-helical structures. in this project we analyze the solution structures of these peptides at the atomic resolution using 2d nmr supported with molecular dynamics. design and conformational analysis of stapled peptides mimicking cullin3 binding region to kctd11. i. de paola, a l. pirone, a e. pedone, a s. di gaetano, a l. vitagliano, a r. fattorusso, b g. malgieri, b l. zaccaro*, a acknowledgement: this study was supported by eu within the european regional development fund (poig. 01.01.02-00-007/08-04). model of angiotensin ii bound to the at1 receptor in the lipid bilayer environment m.t. matsoukas, t. tselios* department of chemistry, university of patras, gr-26504, patras, greece the renin-angiotensin system () plays a major role in blood pressure regulation. a sequence of enzyme reactions leads to the release of angiotensin ii which interacts principally with the type-1 angiotensin ii receptor (at1), a 359-residue, which belongs to the g protein-coupled receptor family. in the present study, the human at1 3d model was constructed using modeler for the sequence alignment and loop refinement tools. on this basis, the crystal structure of bovine rhodopsin, (pdb code 1u19), was used as a 3d template. the gromacs software and amber99sb forcefield were utilized for molecular dynamics calculations [1] in order to evaluate the binding mode of angiotensin ii. the role of the critical amino acids of the binding site v108, n111, l112, a163, k199, s252, h256, n294 and y292 is being studied. moreover, newest information on the role of the 2 nd extracellular loop by unal et. al. [2] have been implemented on the model, therefore we propose the contribution mechanism of the residues f170-q187 for binding of angiotensin ii to the at1 receptor for activation and signaling. a. stavrakoudis department of economics, university of ioannina, greece one key step in the immune response against infected or tumor cells is the recognition of the t-cell receptor (tcr) by class i major histocompatibility complexes. it has been found [1, 2] that such peptide/mhc complexes can interact with antibodies as well. this happens mainly in the central part of the peptide in class i complexes [1] , or at the cterminal of class ii complexes [2] . in some cases, the same peptide/mhc complex has been found to interact with both tcr and antibodies [3] . in these study a series of supermolecular complexes have been studied with stateof-art molecular dynamics simulations [4] the dipeptide kyotorphin (tyr-arg, kyo) plays a role in pain modulation in the mammalian central nervous system (cns), and is one of the most investigated neuropeptides. the tyr-arg motif exists widely throughout the brain not only as kyotorphin, but also as the n-terminal part of several endogenous analgesic peptides 1,2 . also, this peptide is very rapidly degraded by aminopeptidases 3 . one of the successful strategies in the design of neuropeptides with enhanced stability and improved delivery to the cns is that with the use of non-protein amino acids, like canavanive (cav), a structural analogue and antimetabolite of arginine (arg trichogin ga iv (noct-aib-gly-leu-aib-gly-gly-leu-aib-gly-ile-lol, in which noct is n-octanoyl and lol is leucinol) is an antimicrobial lipopeptaibol, a unique group of membraneactive compounds of fungal origin, characterized by a high content of the nonproteinogenic ca,a-disubstituted glycine aib (a-aminoisobutyric acid). owing to the gem-dimethyl substitution on the c a atom, aib exhibits a strong propensity to induce β-turns and 310/α-helical conformations in peptides. we have previously reported on a fluorescent analog of trichogin ga iv, the primary structure (and acronym) of which are: fmoc-aib-gly-leu-aib-gly-gly-leu-toac-gly-ile-leu-ome (f0t8) where fmoc is fluorenyl-9-methyloxycarbonyl, toac is 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid, and ome is methoxy. the double substitution of an energy donor (fmoc) at the n-terminus and an acceptor (toac) in the trichogin sequence enabled us to make use of time-resolved optical spectroscopies, spanning from the nanosecond to the microsecond time regime, to investigate the conformational propensity and the dynamical features of f0t8. experimental and computational results indicated that the 3d-structural and dynamical properties of f0t8 are characterized by a transition from an elongated helix to a more compact conformation mimicking a helix-turn-helix motif. to further investigate the role of the flexible gly5-gly6 central motif we synthesized a new trichogin analog having the gly6 residue substituted by aib: fmoc-aib-gly-leu-aib-gly-aib-leu-toac-gly-ile-leu-ome (f0a6t8) experimental and computational results indicated that also the f0a6t8 peptide populate two conformations, the dynamics of which were studied at different temperatures using time-resolved spectroscopic measurements. this replacement was demonstrated to stiffen the peptide backbone by reducing the flexibility around the crucial -gly5-gly6-dipeptide unit. the antigen α4β1, a member of the integrin family, is involved in the migration of lymphocytes through endothelium to the site of inflammation. 1 thus, α4β1 antagonists may be useful tools for the treatment of various inflammation disorders such as asthma and inflammatory arthritis. in addition, recent studies indicate that α4β1 integrin promotes angiogenesis by allowing the invasion of myeloid cells into tumors, while α4β1 antagonists prevent monocyte-induced angiogenesis, macrophage colonization of tumors and tumor angiogenesis. 2 aiming to the discovery of novel α4β1 antagonists, a series of new peptide analogues cyclized through cysteine disulphide bonds were synthesized and tested in vivo against angiogenesis in chicken embryo chorioallantoic membrane (cam model) 3 . sar results indicated that: yr-c(cdpc)-conh2 promoted angiogenesis at the higher studied concentration and showed slight inhibition at the lower one, sal-r-c(cdpc)-oh, sal=salicylic acid, showed important inhibition of angiogenesis at dose-dependent manner, yr-c(cdpc)-oh and sal-yr-c(cdpc)-oh both showed no activity on angiogenesis. nmr spectroscopy was applied for the sequential assignment as well as for the elucidation of specific conformational features. experimental noe data were further imposed as distance constraints to a thorough conformational search by applying molecular dynamics simulations. energy refined produced conformers were used as template for the generation of the pharmacophore model associated with the antagonistic activity. such studies are intended to drive a rationalized design and development of this class of inhibitors. hynes r. o. cell, 1992, 69, 11-25. scaffold discovery by phylomers: a novel cd40l specific scaffold derived from glycyl trna synthetase s.r. stone [1] , k. hoffmann [1, 2] , n. milech [1, 2] , p. t. cunningham [1] , m. kerfoot [1] , s. winslow [1] , y-f, tan [1] , m. anastasas [1] , c. hall [1] , m. scobie [1] , p.watt [2] , and r. hopkins [1, 2] [1] drug discovery technology unit, telethon institute for child health research, 100 roberts road, subicao, 6008, western australia [2] phylogica pty ltd, 100 roberts road, subiaco, 6008, western australia biopanning of phylomer 1 phage display libraries against human cd40l yielded a cluster of highly specific overlapping peptide fragments, from three bacterial genomes, corresponding to the highly conserved catalytic domain from the tetrameric gα2β2 class of glycyl trna synthetases. structural analysis of the overlapping peptide fragments described a scaffold consisting of a central βsheet, comprising 4 anti-parallel β-strands, flanked by nand c-terminal α-helices. further structural analysis revealed that these key structural features, which also encompass the crucial atp-binding motifs of the catalytic domain, are conformationally conserved across both tetrameric gα2β2 and dimeric gα2 glycyl trna synthetases, yet importantly, there is only limited sequence conservation across these classes. given the identical function of the described domain and it's structural conservation, we postulated that members of the dimeric gα2 class would display similar cd40l specific binding as the tetrameric gα2β2 class, despite the sequence dissimilarity. to test this hypothesis, structurally equivalent peptide fragments of representative bacterial, archaeal and eukaryotic genomes comprising the dimeric gα2 class were tested for cd40l binding in a process we termed ortholog scanning. the results showed that both archaeal (p. horikoshii) and eukaryotic (h. sapiens) structurally equivalent peptides bound to cd40l with reasonable specificity and inhibited the cd40:cd40l interaction with comparable ic50's to the primary gα2β2 class sequences. similar results were also observed for the representative bacterial gα2 class peptides. that the sequentially diverse orthologous peptides display cd40l specific binding has important implications to the affinity enhancement strategies to develop the scaffold as a therapeutic agent, and in improving its "drug-like" properties. we have initiated 1 an investigation related to the effect of radical species upon structures of some peptide segments. in the proposed experimental protocol, aqueous peptide solution was submitted to gamma ray irradiation in controlled 1-15 kgy doses. the generation of peptide analogues, possibly induced by reactive oxygen species were examined by electrospray triplequadrupole tandem mass spectrometry (collision induced dissociation approach) and amino acid analysis of crude and/or purified by-products. noteworthy, the gamma irradiation process induced, regardless of the peptide sequence, a non-linear and progressive degradation of all peptides assayed. furthermore, these peptides could be classified in some different classes according to their halflife dose. for instance, the vasoactives angiotensin ii (aii), ang (1-7), bradykinin (bk) and some related peptides were more stable than the melanocyte-stimulating hormone α-msh, substance p or the bk 's (305-325) b2 receptor fragment (lvyvivgkrfrkksrevyqai). usually, the most prominent derivatives generated from this experimental protocol revealed that they are likely induced by oxidation process, yielding a variation of +16 da in their molecular weight. the main source of peptide modifications seems to lie either on the phe (hydroxyl group insertion at o-, m-or p-positions of its aromatic side chain) or met oxydation. in the former case, only phe 8 and not phe 5 is oxidized in the bk structure whereas substance p generates an analogue bearing metsulfoxide without modifying its phe 7,8 residues. thus, collectively, these findings clearly stress the complexity of factors involved in peptide structural modifications induced by gamma ray-type strong electromagnetic irradiation experiment. an additional target of this approach lies indeed, in the production of unusual peptides for further structure-function investigations. university of bern, bern, switzerland linear peptides are typically poor drug candidates due to their low bioavailability and rapid proteolysis. these limitations can be overcome by rigidifying their structure through head-to-tail or side chain-involving cyclizations. cyclic constraints may also increase biological activity by stabilizing secondary structures and by reducing the entropic penalty of binding to a protein target. the use of multiple branching amino acids in a peptide sequence, like diamino acids (as used in peptide dendrimers 1 ) or amino diacids, allows to design peptides resembling polycyclic alkanes, a type of topology only rarely found in nature (e.g. amatoxins and lantibiotics). bicyclic homodetic peptides such as "norbornapeptides" (bicyclo[2.2.1]heptapeptides) were prepared using an orthogonal protection scheme: the first cyclization is performed on resin after selective deprotection of a glutamic acid residue, whereas the second ring closure is achieved by amide bond formation at high dilutions. these peptides are structurally well-defined and cover an almost pristine area of peptide topological space. 2 their conformational rigidity was investigated by means of 2d-nmr and x-ray crystallography and may offer a platform to design drugs tackling protein-protein interactions. the interaction of peptide ligands with protein receptors face peculiar challenge in recognizing binding surfaces due to availability of a multitude of conformations. therefore it is essential to constrain the peptide conformations for the recognition of receptors and thus finding the bioactive conformation. the cell surface receptor protein family integrins recognize "rgd" sequence which is present in different proteins. to determine the bioactive conformation required to bind with receptor αiibβ3, the peptide sequence "riprgdmp" from kistrin was inserted into cdr 1 loop region of rei protein (rei-rgd34). it helps out in finding the possible bioactive conformation of peptide by restricting the sampling space. the activity of rei-rgd34 was studied and found that as the temperature increased rei-rgd34 showed a higher affinity towards the receptor αiibβ3. the proposed mechanisms for the increased activity of rei-rgd34 at higher temperature were justified in either of two ways. the modified complex forces the restricted peptide to adopt a bioactive conformation or it unfolds the peptide in a way that opens its binding surface with high affinity for receptor. in this study we model the conformational preferences of "rgd" sequence in octapeptide "riprgdmp" at two different temperatures (250 o c and 420 o c) using multiple md simulations. we found that at higher temperature "rgd" sequence from "riprgdmp" adopt turn conformation, while a bend conformation was observed at low temperature. the analysis of various pharmacophoric parameters hint that the turn conformation of "rgd" sequences adopted at higher temperature could be the potential bio-active conformation, and helps out in designing of antagonists for cell surface receptor αiibβ3. the 14-residue peptaibol antibiotic trichovirin i-4a (tv) of the linear, covalent structure ac-aib-asn-leu-aib-pro-ala-val-aib-pro-aib-leu-aib-pro-leuol (ac, acetyl; aib, α-aminoisobutyric acid; leuol, l-leucinol) has been synthesized1 and very thin (~25 μm) hair-like crystals were obtained from a methanolacetonitrile-water mixture. diffraction data were collected at 100 k at the diamond light source england, using the microfocus beamline 2 i24 and a x-ray beam focused to a size of 10 μm full-width-half-maximum. two independent molecules (a) and (b) were located in the crystal's asymmetric unit 3 . both chains assume 4 complete turns of a curved 310 right-handed helical conformation stabilized by intramolecular hydrogen bonds. up to now tv represents the longest right-handed 310-helix of a natural peptaibol sequence complementing those of synthetic, protected homooligo-aibinsulin is a protein hormone that plays a key role in regulation of blood glucose levels and, thus, has widespread impact on lipid and protein metabolism.insulin is known to act through binding to the insulin receptor (ir); however, the structure of the insulin-ir complex is not known. the crystal and nmr structures of insulin represent only inactive storage forms. it is widely acknowledged that insulin must undergo structural changes in the c-terminus of the b-chain upon binding to the ir. in addition, the n-terminus of the bchain may adopt two different conformations in hexamer, known as t-and r-states. the r-state of the n-terminus of the b-chain creates a long b1-b19 central a-helix. the t-state of n-terminus is in an extended conformation. however, the biological relevance of the t/r forms remains elusive 1 . in this study, we have focused on the synthesis of new insulin analogues modified at the nterminus of the b-chain and subsequently correlated their biological activities with their 3d-structures. the invariant residue glyb8 seems to be critical for the t/r transition. glycine can adopt wide range of dihedral angles (φ/ψ) and it occupies significantly diverse dihedral angles in t-and r-states. a-aminoisobutyric acid (aib) is an amino acid with a high helical propensity, which often folds into right-or left-handed α-helix. we have introduced aib at position b3, b5 and b8 with the aim to induce the r-state of the hormone. in contrast, as d-pro and nmeala are not able to adopt the φ/ψ angles of the right-handed α-helix we have introduced these amino acids at position b8 to obtain the t-state of insulin. peptide dendrimers are tree-like molecules formed by alternating functional amino acids with branching diamino acids such as lysine. 1 unfortunately these molecules have not yielded to structural characterization and little is known about their molecular-level structure. computational methods seem to be an adequate tool to address these issues.herein we present a comprehensive structural characterization of peptide dendrimers using molecular simulation methods. 2 multiple long molecular dynamics (md) simulations were used to extensively sample the conformational preferences of several third-generation peptide dendrimers, including some known to bind aquacobalamine. we used several conformational analysis procedures (clustering, energy landscapes and multivariate analysis) to analyze conformational changes that can be correlated with particular structural trends.the results point to a high conformational flexibility of these molecules, with no clear "folded state", although two markedly distinct behaviours were identified. some dendrimers favour mainly loose conformations, while others prefer more compact configurations. through a series of computational mutations we investigated the influence of the presence and placement of charged residues in dendrimer topology, finding that electrostatic interactions among charged residues are a major determinant in structure acquisition by peptide dendrimers. these conclusions bring new insight into the conformational behaviour of these systems and may provide better routes for their functional design. acid-mediated prevention of aspartimide formation in solid phase peptide synthesis t. michels, a r. dölling, b u. haberkorn a , w. mier*, a a department of nuclear medicine, university hospital heidelberg, 69120 heidelberg, germany; b biosyntan gmbh, robert-rössle-straße 10, 13125 berlin, germany aspartimide formation is one of the major obstacles that impede the solid phase synthesis of large peptides and proteins. the main reason for aspartimide formation is the piperidine-catalyzed fmoc cleavage of peptides containing aspartic acid. several side chain protecting groups have been developed 1 but the complete prevention of aspartimide formation can only be achieved using n-(2hydroxy-4-methoxybenzyl) (hmb) as backbone protecting group. 2 however, hmb-protected building blocks are difficult to synthesize and only the dipeptide containing glycine (fmoc-asp(tbu)-(hmb)gly) is commercially available. until now, no cost effective strategy to suppress this side reaction has been developed. formally, aspartimide is the result of an attack of an amidate species at the carbonyl carbon of the otbu protected side chain carboxylate of aspartic acid, which might be prevented by protonation of the amidates with piperidinium ions. in this work the suppression of aspartimide formation by adding small amounts of organic acids to the deprotection agent piperidine was studied. this procedure was shown to efficiently prevent the formation of aspartimide side products in several peptides, i.e. pres9-33-y, a 26-mer peptide derived from the hbv surface antigen and a peptide parathyroid hormone (pth) fragment. the testing of a series of 18 different acids covering a broad range of pka values showed that this effect is virtually independent of the acid strength. since aspartic acid is found in most oligopeptides, the authors recommend to generally add 5% (v/v) formic acid to piperidine based fmoc cleavage mixtures. decomposition of the resin linkers during tfa cleavage of peptides in fmoc-strategy leads to alkylation of sensitive amino acids 1 . this side product formation is a crucial drawback, especially during the synthesis of biologically important cys-containing peptides on wang support. through a battery of approaches (1h-nmr, uv and lc/esi-ms) we detected an unexpected alkylation of the sulfhydryl group of cysteine side-chain residues by the phydroxyl benzyl group from the wang resin linker. herein, we present the feasibility for s-alkylation of cys-containing peptides from wang linker decomposition. this sidereaction occurs during the final tfa cleavage of the peptide from the solid support, while the position of the cysteine residue within the peptide sequence as well as the resin's substitution influence the extent of cys-alkylation. the stephan angeloff institute of microbiology, bulgarian academy of sciences, sofia, bulgaria influenza viruses cause epidemics and pandemics all over the world. therefore, the development of virus resistance to drugs, leads to search for novel derivatives and approaches to chemotherapy for human influenza infection. antioxidant therapy is known to be one potential approach. the application of combination therapy of antioxidants with antiviral drugs could reduce the complications and lethal effects, caused by an influenza virus 1 . in our study, amino group of neuraminidase inhibitor -oseltamivir, which belong to second generation anti-flu drugs, was covalent conjugated with known antioxidantscysteine, histidine. tryptophan and etc. the study of the role of the modified by antioxidants oseltamivir on proliferation of influenza virus is in progress. recently we reported a short synthesis of 5 or 6-membered cyclic guanidine via intramolecular reaction of alkyl diamine with n,n'-cbz-methylisothiourea(1a). here we report a further application of synthesis two types of cyclo-peptide guanidine-bridged cyclopeptides utilizing this mechanism -n-terminus local cyclo-guanidine peptide and backbone guanidine-bridged marco-cyclic peptide. three n,n'protected diaminoacids (daa) including 2,4-diaminobutyric p334. antifreeze glycoproteins (afgps) are found in the deep sea teleost fish in arctic and antarctic oceans. these biomolecules are able to inhibit the growth of ice crystals and depress the freezing temperature of the blood serum in fish enough to keep them from freezing in their sub-zero environments while the melting temperature remains unchanged 1 . despite afgps have been consider as a potent cryopreservation, obstacles to develop afgps as medicinal and industrial application are mainly due to the lack of access to pure form from natural sources and the problem of understanding how afgps inhibit ice crystal growth. as a result, a considerable progress toward the design and synthesis of afgp analogues has been made several groups 2 . in the course of the studies on the structure-activity relationships of afgps, we are interested in peptoids as mimics of α-peptides and synthesized monoglycosylated peptoid analogues by substituting the glyco-thr residue as afgps mimics. in this presentation, we will show our studies on how the insertion of peptoid residue into afgp backbone affects the afgp activity by measuring both thermal hysteresis (th) and ice recrystalliztion inhibition (iri). [1] , both for diagnosis and endoradiotherapy. for this application the peptides can be attached with chelating agents that bind radioactive metals such as 67 ga, 68 ga or 111 in for imaging or therapeutic radiometals such as 90 y and 177 lu. the chelating agent most frequently applied is the macrocyclic ligand 1,4,7,10-tetraazacyclododecane-n,n',n'',n'''-tetraacetate (dota), it is commonly introduced as the tris(tbu ester). the cleavage of the tbu protecting groups on dota is known to be sluggish [2] . several attempts have been made to synthesize dota with protecting groups that can be removed under mild conditions. however, these derivatives have not yet found widespread application. our new approach was to prepare a protecting group for dota-based prochelators that is convergently cleaved under the cleavage conditions of the amino acid protecting groups of the peptide. o-phenylisopropyl (opp) esters are more sensitive towards acid than tbu esters. deprotection occurs with 2% trifluoroacetic acid in dichloromethane [3] . therefore, a synthesis of the prochelator dota-tris(opp ester) was developed. the copper-catalyzed azide-alkyne cyclization (cuaac), the most commonly recognized variant of "click chemistry," has emerged as a powerful technique for ligation, conjugation, and cyclization reactions of peptides. it is known that cyclization can increase the metabolic stability of peptides, as well as enhancing potency or selectivity by stabilizing an active conformation. one application of the cuaac that has generated interest is the use of this reaction to replace a disulfide bridge with the product triazole, which among other complementary properties may prevent in vivo redox chemistry. in this poster, we synthesize a new analogue of the cyclic cancertargeting peptide cngrc where we replace the disulfide bond with a triazole linkage using click chemistry and a fully automated, on-resin method using the single-shot delivery feature on the prelude® peptide synthesizer. unnatural amino acids including d-amino acids are manufactured mainly by the enzymatic process. however, one enzyme can produce only one amino acid due to its high specificity and it takes a long time and a lot of expenses to develop the appropriate enzyme itself. arca (alanine racemase chiral analogue) is an organic catalyst1 which can overcome these drawbacks and can produce almost all kinds of amino acids efficiently. the amine functionality of l-threonine is freely reacted with the aldehyde group of arca to form the corresponding imine, which is easily epimerized in the presence of organic base due to the acidity of the alpha proton of imine. the difference in the stability between the imines of the optical epimers rendered them to be shifted to d-allo-threonine derivative dominantly. once the epimerization reaction reached equilibrium, the reaction mixture was hydrolyzed under acidic condition to give d-allo-threonine and arca, which could be recycled repeatedly without significant loss in yield or purity to produce more d-allo-threonine from lthreonine in excellent yields. optimization of the reaction conditions with various bases and solvents is discussed and mass production of optically active d-allo-threonine including optical purification is described. the manufacuring process for the preparation of arca will be shared as well. our group is interested in the development of efficient synthetic routes for the preparation of enantiopure atrifluoromethylated amino acids (a-tfm-aas) starting from chiral cf3-oxazolidines or imines 1 and their incorporation into a peptide chain. 2 these non-natural amino acids are very attractive compounds for the design of biologically active molecules, particularly peptides, due to the unique physical, chemical and biological properties impart by the cf3 group. 3 as conformationally constrained cyclic amino acids have recently gained considerable interest, we are particularly focused on the preparation of pyrrolidine-type a-tfm aas. 1, 4 incorporation of proline derivatives is known to restrict the amino acyl-proline cis/trans isomerization, to limit the protein folding and consequently to modulate the biological activity of peptides. based on these observations, mutter's group introduced pseudoproline building blocks (ψpro) into a peptide sequence as reversible protecting groups for ser, thr and cys. 5 the ψpro residues proved to be versatile tools for overcoming the aggregation caused by hydrophobic interactions encountered during solid-phase peptide synthesis (spps). they also turned out to be inducers of βturns containing predominantly cis-amide bond and useful tools in peptide cyclization. here, we report the results obtained for the preparation of various hydrolytically stable trifluoromethylated pseudoprolines (cf3-ψpro) as well as the methodological studies developed to optimize the synthesis of various c-and n-terminal cf3-ψpro containing dipeptides. rennes, france protein strructure and function rely on a still not fully understood interplay of energetic and entropic constraints defined by the permutation of the twenty genetically encoded amino acids. many attempts have been undertaken to design peptide-peptide interaction pairs and synthetic receptors de novo by using special building blocks. 1 a rational approach starting from hydrazine to create new building blocks based on a tailored metalchelating amino acid analogues was envisaged. to create chemical recognition units, which bind oligohistidine tags with high affinity and stability, several supramolecular entities containing one to three nitrilotriacetic acid analogue (ynta) moieties were synthesized. these new building blocks additionally contained an amino group or an acido group, which can be flexibly introduced into peptide in n or c-termini or into the peptidic chain by solid phase chemistry in fmoc/t-bu strategy. these multivalent chelators were characterized and the corresponding metalchelating peptides could act as metal sensors and synthetic receptors for histidine-tagged proteins. the potential of peptides as drug candidates is often limited by their pharmacokinetic properties. structural modification of the peptide backbone via n-methylation is a powerful medicinal chemistry tool that confers oral bioavailability to these molecules. n-methylation exerts a strong effect on the backbone conformation and, as a result, many n-methylated peptides show enhanced biological activity and higher receptor selectivity. another approach to increase the solubility of peptides is by conjugation of peg to a derivatizable functionality. by combining these two approaches we have developed n-oegylation. this novel form of peptide modification consists of the attachment of oligoethylene glycol (oeg) chains to the amide bonds. many bioactive peptides comprise one or more n-me amino acids which are essential for their activity. thus, we consider that replacement of a backbone n-me group by an oeg chain may imply a minimal structural perturbation and may lead to n-oegylated peptides with preserved biological activity. furthermore, our strategy is a promising way to improve the bioavailability of cyclic peptides that do not have any site where a peg could be attached. as a proof of principle, several n-oeg analogs of two bioactive cyclic peptides were synthesized in spps. first, we performed a full n-oeg scan of the sansalvamide a peptide. next, several analogs of cilengitide were prepared by replacing the n-me of valine by oeg chains of different length. depending on its size, the oeg residue was incorporated by using an n-oeg derivative as building block or, alternatively, using an n-substituted amino acid bearing an attachment site where a peg was conjugated post-synthetically.the biological activity of all the n-oegylated peptides was evaluated. some of the sansalvamide a peptide analogs exhibited cytotoxicity within the same range as the original peptide, which suggests that backbone amide groups may be useful oegylation sites in bioactive cyclic peptides. the modification of peptides is an important step in pharmacology to vary the affinity and the stability of peptidic drugs. whereas a wide range of strategies exists for the functionalization of the n-terminus and the side chains, facile variation of the c-terminus remains an important challenge. we consider peptidyl-phosphoranes as a promising platform to enable orthogonal and mild introduction of a great variety of chemical functionalities at the c-terminus. a convenient method for the synthesis of soluble peptidyl-phosphoranes has been presented by our group recently. 1 in this, 2-bromo-acetyl bromide was coupled to a wang-resin followed by alkylation of triaryl-or trialkyl phosphine moiety. deprotonation to the phosphorus ylide and subsequent acylation with an fmocamino acid created the basis for assembly of the peptide by spps. final acidic cleavage produced a decarboxylated and unprotected, soluble peptidyl-phosphorane. from this point, a variety of orthogonal modification reactions at the peptides c-terminus is possible, e.g. click reaction with azides allow for the incorporation of triazoles as peptide bond mimetics. the wittig reaction opens up another interesting portal for c-terminal modification, as vinyl ketones are formed by reaction with aldehydes. the described chemistry was applied to modify caspase-3 inhibitors. in order to address the s1 site of caspase-3, the commonly known devd inhibitor was varied at the c-terminus by introduction of different residues. the devd motif was synthesized as peptidyl-phosphorane and modified in wittig reactions. the resulting c-terminal vinyl ketones were obtained by the reaction of aliphatic and aromatic aldehydes. a small library was generated, and 12 novel compounds were tested for their potential to inhibit caspase-3. semmelweis university, department of biophysics and radiation biology, budapest, hungary considering the impact of uv irradiation on the structure and function of proteins 1 , it is a matter of utmost importance to resolve the conditions of photolysis more deeply. we think that a protein, as a complex unit, gives multiple responses to all impacts therefore the analysis of these responses is a rather complex problem. the main goal of our research is the deeper understanding the tryptophan-mediated photolysis of disulphide bridges in bio-active proteins upon near-uv irradiation using cyclic peptide models, as small protein units, to define the caused functional damage. cation -pi interaction is increasingly recognised as an important noncovalent binding interaction which plays a role in establishing the final structures of proteins. within a protein, cation -pi interactions can occur between the cationic side-chains of either lys or arg and the aromatic side-chains of phe, tyr or trp 2 . our earlier results with gla indicate that new covalent bonds are also formed between cys and lys during illumination, which is also a reason why the lys residue is planned to be included in the sequence of the models. our aim is to study whether the cation -pi interaction can have an influence on the ss-bridge splitting in small cyclic pentapeptide models. here we report about the conformational analysis, synthesis and spectroscopic investigation of lys-and arg-containing model peptides. the azide functionality is very popular mainly due to azidealkyne click chemistry 1 used in many peptide ligation strategies. azido-peptides are usually prepared by incorporation of azide containing residues or azide functionalization of aldehyde resins affording c-terminal azido-peptides. 2 alternatively, the n-terminus can be converted into an azide via a cu(ii)-catalyzed diazotransfer reaction using triflyl azide. 3 recently, a number of safer, shelf-stable and easily prepared diazotransfer reagents has been developed, of which imidazole-1-sulfonyl azide has been used to introduce azide moieties in proteins under copper-free conditions. typically, it has not been reported to be used on the solid phase. 4 we provide a very easy, fast and efficient method for conversion of amines into azides on a solid phase support which in our opinion has major benefits over earlier reported methods making using of less stable reagents that require a metal ion catalyst. we demonstrate how the diazotransfer reaction can be performed on a solid phase support using the imidazole-1sulfonyl azide reagent without the need for a metal ion catalyst. using a model peptide we studied the effect of stoichiometry, added base and solvent. in addition we examined the effect of the nature of the n-terminal residue on the efficiency the diazotransfer reaction. finally, we found that the optimal conditions to perform the reaction also depend on the nature of the solid phase support the reaction is performed on. the novo nordisk foundation center for protein research, university of copenhagen, copenhagen, denmark site-selective strategies for post-translational modification of peptides and proteins are essential tools for many areas of research in the life sciences, yet remain a chemical challenge due to the multiplicity of functional groups present. there are powerful chemoselective reactions, however, they aim at introducing only one functionality at each reaction site. here we present a one-pot, threecomponent dual-functionalization of peptides or proteins based on a 1,3-dipolar cycloaddition between a functionalized malemide, an n-hydroxylamine and a peptide or protein with an n-terminal serine residue at the n-terminus, which is selectively oxidized to a 2-oxoaldehyde. most common moieties for labeling, e.g. fluorophors and peg-chains, are commercially available as maleimides. nitrones were easily obtained by condensation of peptide-aldehydes and primary nhydroxylamines under aqueous conditions. the chemoselective 1,3-dipolar cycloaddition reaction between the peptide-nitrone, and a functionalized maleimide proceeded in aqueous solution at room temperature or with gentle heating, which provided the stable isoxazolidine product. we envision that this 'one site -two functions' method can be used widely to introduce two separate moieties. the method was used to introduce two separate ligands in a range of other peptides. for example, new multimodal molecular imaging techniques depend on facile chemical methods for site-selective dual-functionalization. we used our new methodology to synthesize a cyclic rgd-peptide for combined pet and optical molecular imaging. finally, the small protein ipb3 was successfully n-terminally modified, including with a peg-chain, using this new, general method. multiple sclerosis (ms) is the most known chronic, inflammatory, demyelinating disease of the central nervous system (cns), characterized by a progressive neurodegeneration, caused by an autoimmune response to self-antigens in genetically susceptible individuals. it is nowadays known that post-translational modifications may affect the immunogenicity of self-protein antigens, triggering an autoimmune response and creating neoantigens; in particular aberrant glycosylations affect various parts of the immune response and have profound effects on immune tolerance. in previous studies we demonstrated the value of the glycopeptide csf114(glc) which, by virtue of the particular type i' β-turn structure, optimally exposes the minimal epitope asn(glc) to autoantibody recognizing in elisa in multiple sclerosis patients' sera 1 . elisa assays allowed to conclude that the ability in detecting autoantibodies in multiple sclerosis sera was stricktly linked to saccharidic moieties and to conformation around minimal epitope of the antigenic glycopeptide. herein, taking advantage of such considerations, we focused our attention on the synthesis of a little library of lysine branched multiple antigen peptides (maps), containing the minimal epitope asn(glc), in an attempt to increase the antigenicity of linear peptide sequences 2 . with this aim, we performed the spps of glucosylated maps via the building block approach, studying the role of different long spacers on the dendrimeric core, and the role of different peptide sequences around the sugar moiety, in order to optimize the synthetic process and to evaluate the influence on the affinity and specificity in sp-elisa. environmentally induced co-or post-translational modifications of autoantigens are hypothesized to break immune tolerance leading to self reactivity in pbc. 1 it has been previously reported that the use of synthetic post-translationally modified peptides, introducing fmoc-l-lys(nε-(±)-α-lipoic acid)-oh, as peptidomimetics of natural neoantigens allowed to detect autoantibodies in the sera of patients affected by pbc, and they might be useful diagnostic tools that can be used in earlier stage patients and possibly to monitor disease activity. 2 only the r-(+)-enantiomer of α-lipoic acid exists in nature and is an essential cofactor of four mitochondrial enzyme complexes. 3 but it remains unclear if the tridimensional structure of the lipoic acid is of any importance in the interactions antibody-peptide during the indirect elisa tests. therefore, it is necessary to synthesize each peptide separately with one absolute configuration of the lipoic acid. herein, we describe the synthesis of the two diastereoisomers fmoc-l-lys(nε -(r)-α -lipoic acid)-oh and fmoc-l-lys(nε -(s)-α-lipoic acid)-oh that have to be used in fmoc/tbu spps as building blocks for the synthesis of post-translationally modified peptides. 2 recently it has been reported the introduction of a new generation of cd diagnostics based on a unique antigen approach, consisting on human ttg cross-linked with gliadin peptides coated on the elisa plates 3 . on the basis of experimental data obtained by mass spectrometry and indicating which are the fragments of these two proteins that are supposed to be involved in the antibody recognition, we were able to select the most representative ttg and gliadin fragments 4, 5 to design and synthesize by fmoc-spps nine cross-linked eoepitopes. aim of our study was the characterization of autoantigenic epitopes by testing, in celiac patients' sera, the reactivity of these nine synthetic peptides. these neoepitopes were tested in elisa to evaluate the iga and igg response against ttg-gliadin adducts in celiac patients' sera in order to develop a new elisa test based on peptides as an even more powerful diagnostic tool in terms of specificity and sensitivity. 1 more than 80 analogs have already been described, wherein the hydroxy acid and the amino acid constituents were replaced by d-amino acids and/or n-methyl amino acids with preserved or altered side chains. for certain types of cancer cells, several of these analogs were found to be more active than the natural product itself. 2 however, it does appear that many of these compounds have limited solubility in water. 2b here we report the synthesis of 5 novel analogs of the sansalvamide a peptide bearing an n-oligoethyleneglycyl (oeg) chain attached to the different backbone positions. attachment of this chain is aimed to enhance the hydrophilicity of the original peptide. our synthetic strategy to modify the backbone with the n-oeg group relies on the use of n-oeg amino acids, which were synthesized in solution and then used as building blocks in spps. as expected, couplings to the n-oeg residues were found to require special conditions. methods for the coupling to nmethyl amino acids were applied and this enabled to obtain the different linear pentapeptides, which were cyclized in solution. both the synthetic strategies of these demanding peptides as well as the preliminar evaluation of their biological activity will be deeply discussed. glycoconjugates such as glycoproteins and glycolipids have important roles in cell functions, for example, intercellular recognition, cell proliferation control, and information transmission. in order to study the structurefunction relationship, synthesis of these glycoconjugates is essential. glycoproteins and glycopeptides are classified into two categories: n-and o-glycosylated derivatives. the n-acetyl-α-d-galactopyranosylated ser or thr derivatives [ser/thr(α-d-galnac)] are important intermediates for o-glycopeptide synthesis. however, the synthesis of ser/thr(α-d-galnac) derivatives by chemical glycosylation is difficult because of the decreased nucleophilicity of hydroxy function in the glycosyl acceptor due to an unfavorable hydrogen-bonding pattern between the oh and α-nh groups 1 . several approaches to overcome this problem have been reported 1, 2 . in addition, the o-glycosidic bond is cleaved easily in acidic conditions. in this study, we assumed that the formation of a cyclic structure containing an α-nh group would increase the reactivity of oh function. thus, we focused on the n, n'isopropylidene derivatives of ser/thr containing dipeptides 3 . we found the reaction of mannopyranosyl trichloroacetimidate and the n, n'-isopropylidene dipeptide in the presence of tmsotf in dichloromethane produced the desired glycosylated dipeptide in good yield. however the selective intermolecular disulfide bond formation is a very difficult and complicated synthetic problem. in this work we report on synthetic approaches for the formation of conjugates with intermolecular thioether or disulfide bonds. for the disulfide bond formation, we use two activation approaches: i) activation of the four cys residues of the carrier testing two activating reagents, in both solid and liquid phase respectively and ii) activation of the cys containing bioactive molecule. as bioactive molecule we selected the r 997 ppleed 1003 sequence derived from the intracellular part of the αiibplatelet integrin receptor. this region is critically involved in platelet aggregation and is a target of intervention for developing antithrombotic agents 2 . the ac-[lys-aib-cys(ch2co-αiib997-1003)]4-nh2 and ac-[lys-aib-cys(cys-αiib997-1003)]4-nh2 conjugates were synthesized and examined for their ability to inhibit platelet aggregation. the biological assays indicated that the synthesized conjugates penetrate the platelet membrane and inhibit human platelet aggregation, in contrast to the corresponding free peptide analogues. the molecules were reported to exhibit broad-spectrum cytotoxicity against the tumor cell lines. although these peptides contained the novel β-methoxytyrosine, lipton et al. reported the synthesis and cytotoxicity of desmethoxycallipeltin b, in which substitution of d-tyrosine for β-methoxytyrosine did not substantially affect the cytotoxicity of callipeltin b 3, 4 . however, a structure-activity relationship study of the molecules has not been shown to date in detail. in the course of our recent research regarding the synthetic study of cyclic depsipeptides, we conducted studies on the synthesis of callipeltins supposed to be efficient structures for ccr5 inhibitors as anti-hiv drugs or anti-cancer agents. in the present study, we report the synthesis of cyclic depsipeptides of callipeltin b analogues consisting of l-, d-amino acids and/or n-methyl amino acids, for a structure-activity relationship study of linear-and cyclic depsi-peptides against hela cells5. in the assay of synthetic peptides, all of the synthetic callipeltin b analogues exhibited no cytotoxicity. we supposed that dimethylpyroglutamic acid of callipeltin b was essential structure to show the cytotoxicity against hela cells. monash university, melbourne, australia protein-protein interactions represent a significant portion (15-40%) of all interactions within the cell; 1 as such these interactions are ideal targets for drug discovery. while difficult to target using small molecules, these interactions can be disrupted using a small section of the protein's binding partner. these short peptides must retain the defined secondary structure associated with the protein binding interface in order to inhibit their protein targets. as the secondary structure adopted by the parent protein is not always exhibited by its derived peptides, constraints are introduced as necessary to help define the structure of the peptide. inducing secondary structure reduces the energy required for organisation, decreasing the energy of binding and has the potential to increase stability with respect to degradation by proteases. 2 solid phase peptide synthesis was used to make several small peptides corresponding to the structured sections of the binding partners for three protein-protein interactions. these peptides were designed to target heart disease, prostate cancer, and liver cancer respectively. secondary structure was introduced using lactam bridge constraints. for the αhelical peptides, a side chain constraint approach was used to nucleate helix formation. as hydrogen bonding between the c=o of the i th residue and the nh of the (i+4) th residue stabilises native α-helices, constraints were introduced linking the side chains such that the residues were held in close proximity. for β-pleated peptides, an antiparallel β-sheet arrangement was achieved by introducing turn regions into the peptide in such a way that the β-strands were aligned. constraints were again introduced using lactam bridges between lys and arg or glu side chains. these peptides were characterised by nmr and cd spectroscopy to verify the correct secondary structure had been induced. göttingen, germany different properties can be combined in a single molecule by using a scaffold arranging functional groups in a predefined topology. the tasp (template-assembled synthetic proteins) concept describes templates to reinforce and direct the folding of designed molecules into a predetermined topology. [1] due to their resistance to proteolytic degradation and their rigid basic structure, cyclic β -tripeptides are suitable carrier molecules for bioactive compounds; they are further known to form tubelike structures by stacking of the peptide rings leading to higher organization of functionalized peptides. [2] with this scaffold different inhibitory systems were synthesized that feature cell penetrating and fluorescent properties. the signal transducer and activator of transcription 3 (stat3) protein, which has been described as an oncogenic protein, was selected as the first target. [3] a peptide sequence which targets the sh2 domain of stat3 was used in two different approaches. it was either directly attached to the cyclic β-tripeptide via a huisgen [2+3]cycloaddition or the peptide was incorporated into the inhibitor loop of the cystine knot microprotein omcoti-ii, which was also attached to the cyclic-β -tripeptide. [4] further, sodium channels are addressed usingconotoxines. first, an alkyne functionalized conotoxin siiia was synthesized applying different folding methods. the alkyne linker will be used to attach a fluorophore or to functionalize a cyclic-β-tripeptide. using single molecule imaging the spatial distribution, local concentration and organization of the ion channels in neurons will be imaged. further, the cyclic-β -tripeptide templating effect will be used functionalizing with μ-conotoxines. those proteins are folding helper proteins. together with chaperones, they form receptor complexes. they catalyze the isomerization of prolyl bonds in various folding states of target proteins. indeed, their role has been implicated in refolding of denatured proteins, de novo protein synthesis and the biologically active conformation of proteins 1 . among them, the fkbp subclass comprises the small ppi calstabin 1 and 2. it is of interest to try to understand the way those proteins act, in order to help the overexpression of various types of membrane proteins, aiming at the renaturation, purification and crystallization attempts of receptors. we chose to work on calstabin 2 because this short (107 aa) protein has been described as a sub-family comprising 4 isoforms (from ~3 0 to ~1 00 aminoacids), some of them not being fully described to date. the relative shortness of those proteins together with the fact that the two higher molecular weight ones are catalytically active as prolyl isomerases, facilitate the characterization of the synthetic proteins.in order to obtain the full length calstabin 2, a native chemical ligation (ncl) approach was chosen 2 . an optimized stepwise elongation allowed the obtention of the c-terminal segment up to the cys 22. moreover, several methods were compared for the synthesis of peptide 1-21 opportunely functionalized at its c-terminus for the ncl.the ligation at thr site between peptide 1-21 featuring a bis(2-sulfanylethyl)amino 3 the chemical diagnostics of paintings is a relevant topic in the field of chemical sciences applied to the conservation and safeguard of cultural heritage. chromatography is a highly sensitive and suitable technique for accurate methods of analysis of the limited amount of sample material typically available from works of art. paint media deriving from proteins traditionally include egg, milk, animal and fish collagen glue. egg yolk (egg tempera), egg albumin (glair) and casein (a blend of related phosphoproteins commonly found in milk) are traditionally used as pigments binders. we propose the uplc-based amino acid analysis as diagnostics technique on non pre-treated or submitted to extraction processes model samples, showing that good results can be achieved with very scarce sample manipulation and great advantage. we applied the amino acids analysis carried out by the accq•tag™ ultra performance liquid chromatography to the standard and model samples. in particular, after protein hydrolysis (24h, 114 °c, 6m hcl) of the samples, the amino acid derivatization by 6-aminoquinolyl-n-hydroxysuccinimidyl carbamate allowed a reproducible amino acids analysis characteristic of the protein type. the results obtained confirmed the reliability of the data achieved and demonstrated that the accq•tag™ ultra uplc method could be a powerful technique to be applied to the relevant field of protein binders diagnostics for paintings conservation. moreover a multivariate analysis that offers a wide variety of tools and methods mainly concerned with mathematical models for the representation of multidimensional data has been proposed and the high model efficiency has been established for sample containing mixture of proteins. reactions performed on solid supports, such as resin, are commonly monitored by hplc-uv after cleaving the products from the support. however, uv-absorption coefficients may differ between compounds, and therefore the relation of the area percentage values of the peaks may not directly reflect the molar concentrations of the corresponding compounds. it is for this reason that, for example, in solid-phase peptide synthesis it is difficult to calculate the yield of the coupling of a fmoc-amino acid or the removal of the fmoc-group because of its high absorbance. recently, we reported the identification of minimal phosphopeptides that specifically interact with the pbd of human plk1, but not those of the closely related plk2 and plk3 1 . comparative analyses of the crystal structures of the plk1 pbd in complex with the minimal phosphopeptides revealed that the c-terminal spt dipeptide functions as a high-affinity to the interaction. in an attempt to obtain the adequate cellular permeability and stability in vivo, we have accomplished the peptide-peptoid hybrid or peptomers cyclization using various methods like formation of amide, thioether and triazole and screened the plk1 inhibition activity on the first cyclic peptomers liibrary using pbd-binding assay. based on our first screening results, we also carried out the detailed investigation to further increase the activity and also to understand the significance of peptoid mimics as plk1 inhibitors. the mode of interaction between the cyclic peptomers and pbd might provide a template for designing therapeutic agents that target plk1. a synthetic 83 amino acid long peptide corresponding to the minimal metacaspase catalytic domain induces cell death in leishmania major c. servis, h. zalila*, i. gonzalez, l. lozano, n. fasel department of biochemistry, university of lausanne, epalinges, switzerland despite a lot of controversy during the last decade, there is increasing experimental evidence that cell death (cd) is genetically programmed in lower eukaryotes.in the cd proteolytic cascade of plants and protozoa, caspases are likely replaced by metacaspases that are cysteine peptidases recognizing arginines or lysines in p1position. metacaspases have been found to control cell death in plants. the human protozoan parasite leishmania major expresses a single metacaspase (lmjmca) harboring a central domain with the catalytic dyad histidine and cysteine as found in caspases. metacaspase could therefore be one of the executioners of the death pathway in leishmania.in this work we showed that, in stress conditions, lmjmca precursor forms were extensively processed into soluble forms containing the catalytic domain and this domain was sufficient to enhance sensitivity of parasites to hydrogen peroxide by impairing the mitochondrion function. we tested different lengths of the lmjmca catalytic domain and found that the overexpression of the polypeptide corresponding to amino acids 136-218 was sufficient to sensitize l. major mitochondria to oxidative stress.we synthetized an 83aa long peptide corresponding to the minimal metacaspase catalytic domain (aa136-218) and showed that it has specific metacaspase activity in vitro.we are currently investigating its activity on possible target proteins, which have been identified in a yeast two-hybrid screen. identifying proteins involved in the metacaspase signaling pathway will shed light on the understanding of cd in leishmania and open new perspectives in drug target investigation to fight leishmaniasis and other major infectious diseases. s. alasibi, g. ashkenasy department of chemistry, ben-gurion university of the negev, beer-sheva, israel various factors can affect the conformations and folding states of protein molecules and as a consequence their activity. these factors include amino acid mutations, interactions with other macromolecules, binding to regulatory molecules, and also external changes such as ph jump or shining light. in order to control the folding states and to modulate the functions of peptides and proteins by light, photocleavable groups are usually incorporated into specific residues to mask critical interactions. for example, introducing caging groups into coiled-coil proteins recognition interface affects complex formation and template-assisted ligation reactions, in which the coiled-coils serve as templates to catalyze the condensation reactions between two short peptide fragments 1 . our research group has been studying peptides replication networks, which were made of coiledcoil peptides and analyzed the response of such networks to light as external trigger 1 . it was shown that even replicating networks made up of a small number of molecules can possess complex behavior, considering the wealth of catalytic pathways and transformations. hence, boolean logic operations can provide valuable means to analyze and interpret their behavior 2 . herein, we describe the use of chemical inputs and uv light to manipulate peptides folding and functionality within new synthetic networks. these networks perform complex behavior and, as a result, selective product formation is used to implement boolean operations that have not been achieved before. institute of bioorganic chemistry of ras, moscow, russia earlier, we have shown that n-acylated amino acid nitriles and amides react with ethylene derivatives forming the 3amino-and 3-hydroxypyridines and pyrroles [1] . a possible reaction mechanism is the geterodienic condensation of 5aminooxazole derivatives to dienophiles. the higher yields were observed when used the dicarboxylic acids as dienophiles and 5-amino or 5alkoxyoxazole as geterodienes. while the same reactions with the fullerene derivatives, as dienophiles, gave low yields. the nitrile groups of specified pyridines possess ability to react with amino groups of peptides and proteins even at room temperature. in view of high activity of nitrile groups such pyridines can form tetrapyridotetrazoporphyrins and self-condensation products giving appropriate dendrimers (possible due to mobile hydrogen in the 6th position). high molecular weight dendrimers were identified by massspectrometry, gel electrophoresis and dynamic light-scattering. catalytic oxidizing properties of tetrazaporphyrin derivatives and phtalocyanin were used in synthesis of cyclic peptides and for the s-s bonds formation. the transformation of peptides into heterocycles via an intramolecular reaction of nitrile groups was used to determine the sequence of some peptides, which favored the resistance of transformed compounds to hydrolysis and to the electron impact at mass spectrometry. diazotization of peptides and their derivatives facilitates identification of amino acid sequence by mass spectrometry due to the peculiarities of their fragmentation. in addition, an amino acid analysis of the diazotized peptide makes it easy to determine the n-terminal amino acid. we present here a multi-disciplinary approach combining x-ray crystallography, computational analyses, and immunological tests to identify epitopes of the oligopeptide-binding protein a (oppa bp) from the gramnegative pathogen burkholderia pseudomallei, the etiological agent of melioidosis. 3 computational analysis on oppa crystal structure was used to design potential consensus epitopes, that once synthesized as free peptides (comp 1-3) were found to be immunoreactive against sera from melioidosis patients. notably, one of the predicted peptides allowed to distinguish between seropositive, seronegative and recovered groups, underlining its potential for diagnostic purposes. parallel experimental epitope mapping, based on proteolysis and mass spectrometry, allowed us to identify linear peptide epitopes (exp 4-6) localized in similar protein regions as comp1-3. moreover, the match between theoretical and experimental mapping of epitopes was improved by expanding our computational approach, i.e. including an energy based decomposition procedure to divide oppa bp into separate fragments. overall, our results illustrate the successful development of a novel integrated structurebased approach for the discovery, design and preparation of epitopes. nonetheless, given antigen crystal structures, our method is expected to be broadly applicable in the design and generation of new epitope candidates, as being confirmed by on going experiments on different antigens. the application of peptide thioacids as reactive intermediates and building blocks has received considerable attention recently. the chemical ligation reaction between thioacids and azides has been reported for the synthesis of small to larger peptides as well as for the modification of proteins. 1 fmoc based methods for the preparation of peptide thioacids have to our knowledge not been extensively researched and a facile approach to their synthesis is desirable.we have recently shown that t-butyl thioesters are robuster than previously reported, and can be used for the fmoc based solid-phase preparation of peptide thioesters being also easily cleavable with thiolates. 2 peptides attached via a 4-mercapto 4-methylpentanol (mmp) resin can be cleaved using 3-mercaptopropionitrile to obtain protected thioacid peptides with a ß-elminable cyanoethyl group.the thioacid peptides could then be obtained in situ after treatment with dbu (6.5 % in dmf) and further reacted with sulfonyl azides in the presence of 2,6-lutidine in a one pot reaction. by treating the cyanoethyl peptide thioesters with (nh4)2s in a sodium phosphate buffer (ph = 9), various model penta-peptide thioacids could be obtained cleanly at room temperature in up to 75 % overall yield based on initial coupling. these peptides were then further ligated with electron deficient sulfonyl azide functionalized peptides.larger peptide thioacids could also be obtained using this protocol. a 16mer derivative of penetratin-1, a cell-penetrating peptide from the third helix of the homeodomain of the antennapedia protein, was prepared as a peptide thioacid in a 51 % yield (based on coupling of the first amino acid). in this report, a sensitive, selective and rapid uplc-ms method was developed for the determination of the [lys-gly]5-mog35-55 peptide in order to control the conjugation of mannan with the [lys-gly]5-mog35-55 peptide. the separation was performed on an acquity uplc system with a beh c18 column packed with 1.7 μm particles. the total run time was 3 min. calibration curve based on peak area ratio was linear at the concentration range of 20 -90 μg/ml, with a detection limit of 5 μg/ml. the method showed satisfactory reproducibility and confirmed the entire conjugation between oxidized mannan and peptide sequence. the development of simple, low-cost and fast methods for protein purification is of increasing importance both for academic and industrial applications. a very promising approach is inverse transition cycling (itc) that exploits the temperature dependent aggregation properties of elps. 1 elastin-like polypeptides (elp) are artificial polypeptides composed of pentameric repeats (val-pro-gly-xaa-gly) derived from mammalian elastin. 2 elps are characterized by a specific transition temperature (t t ) that depends on the amino acid composition of the pentarepeat; they are water-soluble below and aggregate reversibly above this narrow temperature range (t t ). 3 these properties are transferred to target proteins by n-or cterminal fusion with elps. 4 during itc these fusion proteins precipitate, while other components remain in solution. repeated cycles of heating and cooling allow simple recovery of the target protein.we synthesized various elps consisting of 5 to 10 pentameric repeats and including different guest residues. the transition temperature of all synthetic elps was determined using photometric assays and measuring turbidity. 3 in order to test if elp properties can be efficiently transferred, we fused elp to a small recombinant protein (ras-binding domain, rbd) by expressed protein ligation. 5 this approach will allow the incorporation of elps with unnatural amino acids and other chemical modifications into target proteins. currently we are focusing on biotechnologically relevant enzymes that constitute a major cost factor in industrial processes. the authors thank süd-chemie/clariant for their financial support. department of pharmacy, university of patras, rio, greece peptides penetrating the cell membrane, known as cell penetrating peptides (cpps), as well as their mimics, used as delivery agents to cells have been reported 1,2 . cpps can be natural sequences or artificial constructs designed to capture the features of natural formations. cpps are particularly important in the delivery of peptides, proteins, nucleic acids, small molecule drugs or imaging agents. incorporation of a heterocyclic motif into a peptide or peptide-like backbone introduces conformational constraints and/or latent reactivity related to the heterocycle's structural profile. heterocycle-based cpp mimics are, thus, promising candidates for therapeutics 3 protected synthetic non-ionic peptides, which are for example synthetic intermediates for the production of api's, are often very hydrophobic and not soluble in most common solvents. they are thus difficult to purify by preparative rp-hplc, classically used for industrial production. it is then challenging to develop alternative purification chromatographic processes using suitable solvents and providing good yields, high purity and sufficient productivity. the technique of support free liquid-liquid chromatography 1 , including both its hydrostatic (centrifugal partition chromatography or cpc) and its hydrodynamic (counter-current chromatography or ccc) declensions, are mainly involved in phytochemical studies 2 but has also been applied to peptide purification 3 . the previously developed biphasic solvent systems are not adapted to the purification of highly hydrophobic protected peptides. to overcome this problem, two new scales of biphasic solvents systems and a ternary biphasic solvent system were developed to overcome solubility problems often encountered with those peptides. the new systems composed of heptane/thf/ch3n/dmso/water, heptane/me-thf/nmp/water, and cmpe/dmf/water were efficiently used for the cpc purification of a 39mer protected exenatide and a 8mer protected peptide intermediate of bivalirudin synthesis. the developed scales show a wide range of polarity and should be useful for general use in cpc for the separation of hydrophobic synthetic free or protected peptides. the progressive aggregation of β-amyloid peptide (β-ap) into insoluble amyloid fibrils ultimately leading to formation of toxic amyloid plaques is widely considered to be the central pathogenic cause of alzheimer's disease. in the last decade accumulating evidence suggests that soluble oligomeric non-fibrillar forms of β-ap are neurotoxic as well. consequently, inhibiting the aggregation of β-ap is one of the therapeutic strategies against alzheimer's disease and a number of small molecules have been identified as inhibitors of β-ap aggregation and neurotoxicity. among these, curcumin, the phenolic yellow pigment and active ingredient of the turmeric herb, is receiving special attention because of its rich pharmacology that includes in vitro and in vivo inhibitory action against alzheimer's disease insults. in the current work the interaction of β-ap(1-40) with curcumin is investigated with fluorescence, cd, and nmr spectroscopies in water and water-methanol mixtures and at various β-ap(1-40):curcumin ratios. in nmr studies in 100% methanol curcumin behaves like a macromolecular species with a change in the sign of its noe signal providing direct indication of its association with β-ap(1-40). in 50% methanol the presence of β-ap(1-40) results in great broadening of the 1 h peaks of curcumin, indicative of a complete change in its solution state. additionally, the fluorescence of curcumin in 50% methanol shows a blue shift with enhanced intensity, observations consistent with a hydrophobic modification of curcumin environment upon interaction with β-ap. finally, in water the induced circular dichroism spectrum of curcumin in the near uv region provides clear evidence for the loss of symmetry of curcumin molecule due to changes in its microenvironment generated by interaction with β-ap(1-40). our experimental findings support the direct interaction of β-ap(1-40) with curcumin and establish its importance as a potential aggregation inhibitor of β-ap. [1] . based on its sequence, we synthesized h-tyr-d-trp-nh-1-ada (1-adamantane) (yo-14) and h-tyr-d-trp-nh-2-ada (2-adamantane) (yo-13) and reported they had potent antiproliferative activity on cancer cells (a-430 and sw480), which were comparable to tt-232 and cycloheximide. a structure-activity relationship analysis revealed that lipophylicity of yo-14 and -13 could be responsible for their antiproliferative activity. now, we described the substitution of tyr of yo-14 and -13 by tyr(bzl), phe, 1-nal(1-naphthylalanine), 2-nal (2-naphthyalanine) and the anticancer and dna polymerase inhibitory activities in order to explore the effect of hydrophobic substituent. among the compounds, yo-113 and -114 had the highest lipophilicity judging from their retention time and lipophilicity index (yo-113: 45.5 min, 59.9; yo-114: 44.6 min, 55.9). yo-113 and -114 exhibited strong dna polymerase inhibitory activity as well as antifroliferative activity on hct116 cells at 100 m. these activities were greater than those of yo-14 and -13. antiproliferative activity of the compounds containing 1-ada such as yo-14, -89, -109, -111 and -113, was comparable to that of the compounds containing 2-ada such as yo-13, -90, -110, -112 and -114. these findings suggest that the lipophilicity well correlates with dna polymerase inhibitory activity and antiproliferative activity on hct116 cells. further structureactivity relationship study is progressing in our group. multiple sclerosis (ms) is a chronic autoimmune disease of the central nervous system (cns) 1,2 . our aim was to immunologically control the attack of the myelin sheath in ms patients without the total suppression of the immune system. anthraquinones (mitoxantrone, ametantrone) are widely used in cancer therapy as immunosuppressants.mitoxantrone is also used to treat several forms of advancing ms, including secondary progressive ms, progressive relapsing ms, and advanced relapsingremitting ms 3 . more specifically, mitoxantrone is an inhibitor of the type ii topoisomerase, which disrupts dna synthesis and dna repair in both healthy cells and cancer cells. herein, we report the synthesis of an anthraquinone type compound conjugated to the immunodominant 35-55 myelin oligodendrocyte glycoprotein (mog35-55) for the selective immunosuppression of the encephalitogenic t cells in ms patients. the anthraquinone was synthesized by a friedel-crafts acylation of hydroquinone from phthalic anhydride, followed by reduction of the resulted quinizarine to its leuco form, addition of the appropriate diamine and air oxidation 4 . the synthesized molecules were purified using liquid chromatography, and they were identified by mass spectrometry and 1 h-nmr. the synthesis of the mog35-55 was performed under microwave irradiation 4 and its conjugation with the anthraquinone was performed in solution. the final analogue was purified by rp-hplc and identified by esi-ms. benzopyrans, diketopiperazines and 1,5benzodiazepin-2,4-diones are well-known and widely investigated scaffolds, e.g. the latter showing anxiolytic and antiarrhythmic effects. now, we propose a new potential "privileged structure" containing a triazole moiety mimicking the cis-amide bond within the 1,5-benzodiazepin-2,4-dione motif 2 .molecules based on this [1,2,3]-triazolo [1,5-d] benzo-1,4diazepin-2-one scaffold are synthesized and decorated via a modular approach on wang resin using α-amino acids, 2-ethynylaniline building blocks and n-alkylating agents resulting in five points of diversity. the methodology involves the attachment of α-amino acids onto a solid support, subsequent removal of the fmoc group followed by an optimized diazotransfer reaction of the resulting amine yielding a resin-bound azide. conversion of the latter into a 1,5-disubstituted 1,2,3-triazole moiety is achieved quantitatively by addition of a range of 2-ethynylaniline building blocks using a ru(ii)-catalyst. the desired scaffold can be obtained in high crude purities (>95%) in solution via an acid catalyzed one-step cyclisation-release strategy. solution-phase n-alkylation finally affords the fully diversified scaffold. interestingly, n-alkylation induces atropisomeric effects which can be studied via 1 h nmr spectroscopy.taking into account future screening results of the synthesized libraries, a well-thought decoration of this scaffold leading to discovery of new lead molecules is within reach. peptide symposium in the wonderful small seaside town of porto carras. maurice manning and lajos balaśpiri were nominated as captains of the two teams, the rest of the world and europe. similar matches were organized at subsequent european peptide symposia. now, in greece, the two captains would like to hand over their roles to younger scientists [professors gabor mezö(hungary) and laśzlóötvös (usa)] to continue this tradition at the coming european and possibly american peptide symposia. it seems best to play in the free time (in the evenings after the excursions). necessary conditions: good weather; a nice large soccer field; a soccer ball, preferably new; and jerseys and shorts (different colours), organized as always by the organizer commettee. the captain of the winning team will receive a trophy at the end of the 32 nd european peptide symposium. the teams will remember two earlier excellent referees: professor lajos kisfaludy in porto carras [1986] and the soccer professor + ferenc puskaś (hungary) in budapest (1998). in the poster session, the results from the past 25 years will be presented in about 15-20 pictures. these pictures may possibly be bought free, 0% can be saved at the poster session. all participants are welcome at the new party in athens. conclusion will be presented by the players and fans in athens. the human lactoferrin-derived peptide, hlf1-11, was proven to be highly active against antibiotic-resistant bacteria 1 . however, the clinical use of this antimicrobial peptide (amps) is hampered by the peptide low stability due to fast degradation or to peptide aggregation, as the use of higher peptide concentrations results on higher toxicity levels. amp immobilization onto a biomaterial surface could be the pathway to overcome these difficulties 2 . the aim of this work is the development of an antimicrobial surface by covalent immobilization of hlf1-11 onto the surface of chitosan thin films. chitosan ultrathin films were prepared through the spincoating of a 0.4% chitosan solution in gold substrates. hlf1-11 immobilization was performed through an ss bound between hlf1-11 terminal cysteine and an n-acetyl cysteine previously coupled at chitosan films. surfaces were characterized using ellipsometry (thickness), infrared reflection absorption spectroscopy (irras) and x-ray photoelectron spectroscopy (xps). bacterial adhesion studies were performed using methicillin-resistant s. aureus (atcc33591). chitosan films were incubated with this bacterial suspension at 37ºc for 6h and 24h. the viability of the attached bacteria was evaluated using live/dead® bacterial viability kit (baclight tm ) and fluorescence microscopy. hlf1-11 peptide was successfully covalently immobilized onto chitosan thin films. both soluble and attached peptide presented a higher antimicrobial activity than the control chitosan. identified as a potent vasoconstrictor that binds with high affinity to ut receptor. 1 the cysteine-linked cyclic region, hut-ii(4-11), is responsible for the biological activity and has been widely used to elucidate the structure-activity relationship of hut-ii. 2 with the aim to investigate the role of hydrogen bond and the effects of a peptide backbone constraint on binding key: cord-352844-wggg3ynb authors: annunziata, francesca; pinna, cecilia; dallavalle, sabrina; tamborini, lucia; pinto, andrea title: an overview of coumarin as a versatile and readily accessible scaffold with broad-ranging biological activities date: 2020-06-29 journal: int j mol sci doi: 10.3390/ijms21134618 sha: doc_id: 352844 cord_uid: wggg3ynb privileged structures have been widely used as an effective template for the research and discovery of high value chemicals. coumarin is a simple scaffold widespread in nature and it can be found in a considerable number of plants as well as in some fungi and bacteria. in the last years, these natural compounds have been gaining an increasing attention from the scientific community for their wide range of biological activities, mainly due to their ability to interact with diverse enzymes and receptors in living organisms. in addition, coumarin nucleus has proved to be easily synthetized and decorated, giving the possibility of designing new coumarin-based compounds and investigating their potential in the treatment of various diseases. the versatility of coumarin scaffold finds applications not only in medicinal chemistry but also in the agrochemical field as well as in the cosmetic and fragrances industry. this review is intended to be a critical overview on coumarins, comprehensive of natural sources, metabolites, biological evaluations and synthetic approaches. coumarins are a wide family of secondary metabolites found in various species of plants (more than 1300 coumarins have been identified from natural sources, especially green plants) but also fungi and microorganisms [1, 2] . the main pathway of coumarin biosynthesis occurs by shikimic acid route, via cinnamic acid, through phenylalanine metabolism [3] . the history of these natural products began 200 years ago-the name of the class derived from the plant coumarouna odorata (dipteryx odorata) from which the simplest member of this family, coumarin itself ( figure 1) , was isolated by vogel in 1820 [3, 4] . chemically speaking, coumarins are organic heterocycles and their nucleus is represented by benzo-α-pyrone (2h-1-benzopiran-2-one), whose systematic nomenclature was established by international union of pure and applied chemistry (iupac) [5] . natural coumarins are subdivided in different classes based on their chemical diversity and complexity-simple coumarins, isocoumarins, furanocoumarins and pyranocoumarins (both angular and linear), biscoumarins and other coumarins such as phenylcoumarins (table 1 ) [6] . coumarins have several attractive features, such as low molecular weight, simple structure, high in a recent work, eight coumarin metabolites, which had not been identified previously, were detected by means of uplc/quadrupole-tof tandem mass spectrometry in human urine [22] . among them, positional isomers of 7-hydroxycoumarin glucuronide and 7-hydroxycoumarin sulphate were found. it was proposed that such isomers should bear the substituent in position 5, 6 or 8. metabolites coming from a double hydroxylation and subsequent conjugation with glucuronic acid or sulphate group (and their isomers) were detected as well. another metabolite was the one obtained by a double hydroxylation of the coumarin ring, followed by methylation and glucuronidation at the two newly generated hydroxyl groups. finally, the n-acetylcysteine conjugated metabolite was identified. in this work, o-hydroxyphenylacetic acid was also detected in the samples, whereas free coumarin and o-coumaric acid were not found, indicating that coumarin was completely metabolized before excretion, after oral administration. this meant that o-coumaric thunberginols (antidiabetic) [19] phenylcoumarins int. j. mol. sci. 2020, 21, x for peer review 3 of 83 thunberginols (antidiabetic) [19] phenylcoumarins isodispar b (anti-inflammatory) [20] this privileged scaffold serves as an important platform for the design of compound libraries in the search for new drug candidates. here, we critically review the actual state of the art on natural and synthetic coumarins, focusing on the biological activity, structure-activity relationships (sars), pharmacokinetics (pks) and their potential applications in the pharma and agri-food sectors. furthermore, an overall overview of the most common synthetic routes applied to obtain simple coumarins are provided, together with a further discussion on alternative, innovative and green synthetic methodologies. coumarin is metabolized by cytochrome p450-linked mono-oxygenase enzyme (cyp2a6) system in liver microsomes, which leads to hydroxylation; subsequently, the hydroxylated metabolite follows phase ii conjugation reactions. although coumarin could potentially be hydroxylated at all six possible positions (i.e., carbon atoms 3, 4, 5, 6, 7 and 8) (figure 1 ), 7hydroxycoumarin and 3-hydroxycoumarin are the main metabolites. the former one faces phase ii conjugation reaction resulting in the glucuronide derivative, whereas 3-hydroxycoumarin can be further metabolized by ring splitting to form two products, o-hydroxyphenyllactic acid and ohydroxyphenylacetic acid ( figure 2 ) [4, 21] . since the expression of cyp2a6 varies between individuals, due to genetic and environmental factors, an inter-individual variation in the metabolism of coumarin drugs is possible [4] . in a recent work, eight coumarin metabolites, which had not been identified previously, were detected by means of uplc/quadrupole-tof tandem mass spectrometry in human urine [22] . among them, positional isomers of 7-hydroxycoumarin glucuronide and 7-hydroxycoumarin sulphate were found. it was proposed that such isomers should bear the substituent in position 5, 6 or 8. metabolites coming from a double hydroxylation and subsequent conjugation with glucuronic acid or sulphate group (and their isomers) were detected as well. another metabolite was the one obtained by a double hydroxylation of the coumarin ring, followed by methylation and glucuronidation at the two newly generated hydroxyl groups. finally, the n-acetylcysteine conjugated metabolite was identified. in this work, o-hydroxyphenylacetic acid was also detected in the samples, whereas free coumarin and o-coumaric acid were not found, indicating that coumarin was completely metabolized before excretion, after oral administration. this meant that o-coumaric isodispar b (anti-inflammatory) [20] this privileged scaffold serves as an important platform for the design of compound libraries in the search for new drug candidates. here, we critically review the actual state of the art on natural and synthetic coumarins, focusing on the biological activity, structure-activity relationships (sars), pharmacokinetics (pks) and their potential applications in the pharma and agri-food sectors. furthermore, an overall overview of the most common synthetic routes applied to obtain simple coumarins are provided, together with a further discussion on alternative, innovative and green synthetic methodologies. coumarin is metabolized by cytochrome p450-linked mono-oxygenase enzyme (cyp2a6) system in liver microsomes, which leads to hydroxylation; subsequently, the hydroxylated metabolite follows phase ii conjugation reactions. although coumarin could potentially be hydroxylated at all six possible positions (i.e., carbon atoms 3, 4, 5, 6, 7 and 8) (figure 1 ), 7-hydroxycoumarin and 3-hydroxycoumarin are the main metabolites. the former one faces phase ii conjugation reaction resulting in the glucuronide derivative, whereas 3-hydroxycoumarin can be further metabolized by ring splitting to form two products, o-hydroxyphenyllactic acid and o-hydroxyphenylacetic acid ( figure 2 ) [4, 21] . since the expression of cyp2a6 varies between individuals, due to genetic and environmental factors, an inter-individual variation in the metabolism of coumarin drugs is possible [4] . int thunberginols (antidiabetic) [19] phenylcoumarins isodispar b (anti-inflammatory) [20] this privileged scaffold serves as an important platform for the design of compound libraries in the search for new drug candidates. here, we critically review the actual state of the art on natural and synthetic coumarins, focusing on the biological activity, structure-activity relationships (sars), pharmacokinetics (pks) and their potential applications in the pharma and agri-food sectors. furthermore, an overall overview of the most common synthetic routes applied to obtain simple coumarins are provided, together with a further discussion on alternative, innovative and green synthetic methodologies. coumarin is metabolized by cytochrome p450-linked mono-oxygenase enzyme (cyp2a6) system in liver microsomes, which leads to hydroxylation; subsequently, the hydroxylated metabolite follows phase ii conjugation reactions. although coumarin could potentially be hydroxylated at all six possible positions (i.e., carbon atoms 3, 4, 5, 6, 7 and 8) (figure 1 ), 7hydroxycoumarin and 3-hydroxycoumarin are the main metabolites. the former one faces phase ii conjugation reaction resulting in the glucuronide derivative, whereas 3-hydroxycoumarin can be further metabolized by ring splitting to form two products, o-hydroxyphenyllactic acid and ohydroxyphenylacetic acid ( figure 2 ) [4, 21] . since the expression of cyp2a6 varies between individuals, due to genetic and environmental factors, an inter-individual variation in the metabolism of coumarin drugs is possible [4] . in a recent work, eight coumarin metabolites, which had not been identified previously, were detected by means of uplc/quadrupole-tof tandem mass spectrometry in human urine [22] . among them, positional isomers of 7-hydroxycoumarin glucuronide and 7-hydroxycoumarin sulphate were found. it was proposed that such isomers should bear the substituent in position 5, 6 or 8. metabolites coming from a double hydroxylation and subsequent conjugation with glucuronic acid or sulphate group (and their isomers) were detected as well. another metabolite was the one obtained by a double hydroxylation of the coumarin ring, followed by methylation and glucuronidation at the two newly generated hydroxyl groups. finally, the n-acetylcysteine conjugated metabolite was identified. in this work, o-hydroxyphenylacetic acid was also detected in the samples, whereas free coumarin and o-coumaric acid were not found, indicating that coumarin was completely metabolized before excretion, after oral administration. this meant that o-coumaric in a recent work, eight coumarin metabolites, which had not been identified previously, were detected by means of uplc/quadrupole-tof tandem mass spectrometry in human urine [22] . among them, positional isomers of 7-hydroxycoumarin glucuronide and 7-hydroxycoumarin sulphate were found. it was proposed that such isomers should bear the substituent in position 5, 6 or 8. metabolites coming from a double hydroxylation and subsequent conjugation with glucuronic acid or sulphate group (and their isomers) were detected as well. another metabolite was the one obtained by a double hydroxylation of the coumarin ring, followed by methylation and glucuronidation at the two newly generated hydroxyl groups. finally, the n-acetylcysteine conjugated metabolite was identified. in this work, o-hydroxyphenylacetic acid was also detected in the samples, whereas free coumarin and o-coumaric acid were not found, indicating that coumarin was completely metabolized before excretion, after oral administration. this meant that o-coumaric acid found in human plasma [23] underwent a biotransformation process before being eliminated, probably leading to o-hydroxyphenylacetic acid. in a healthy human body, normal metabolic processes produce free radicals and other highly reactive species such as ions, molecules with unpaired electrons, reactive oxygen, carbon, nitrogen or sulfur species (ros, rcs, rns or rss). when these species are overproduced, oxidative processes might cause cellular damage, affecting cellular components and causing ionic imbalance or mitochondrial disfunction [24] . the role of oxidative stress in different pathologies is well know: inflammation, cardiovascular diseases, cancer, diabetes and even neurodegenerative disorders often count oxidative damage among their pathological features [25] [26] [27] . therefore, exogenous antioxidants might be useful in order to maintain the right concentration of radicals, reducing the amounts of free radicals and avoiding oxidative stress [28] . the antioxidant potential of natural and synthetic coumarins has been deeply investigated in the last years and it became clear that poly-hydroxy or phenolic coumarins are efficient antioxidants in biologicals systems [29] . here below the most recent updates in this field are reported. in 2019, couttolenc and collaborators studied the radical scavenging activity of three hydroxy-4-methylcoumarins (1-3, figure 3 ) by means of experimental and theoretical methods [30] . int acid found in human plasma [23] underwent a biotransformation process before being eliminated, probably leading to o-hydroxyphenylacetic acid. in a healthy human body, normal metabolic processes produce free radicals and other highly reactive species such as ions, molecules with unpaired electrons, reactive oxygen, carbon, nitrogen or sulfur species (ros, rcs, rns or rss). when these species are overproduced, oxidative processes might cause cellular damage, affecting cellular components and causing ionic imbalance or mitochondrial disfunction [24] . the role of oxidative stress in different pathologies is well know: inflammation, cardiovascular diseases, cancer, diabetes and even neurodegenerative disorders often count oxidative damage among their pathological features [25] [26] [27] . therefore, exogenous antioxidants might be useful in order to maintain the right concentration of radicals, reducing the amounts of free radicals and avoiding oxidative stress [28] . the antioxidant potential of natural and synthetic coumarins has been deeply investigated in the last years and it became clear that poly-hydroxy or phenolic coumarins are efficient antioxidants in biologicals systems [29] . here below the most recent updates in this field are reported. in 2019, couttolenc and collaborators studied the radical scavenging activity of three hydroxy-4-methylcoumarins (1-3, figure 3 ) by means of experimental and theoretical methods [30] . firstly, the scavenging activity of the compounds was evaluated on abts (2,2′-azino-bis (3ethylbenzothiazoline-6-sulfonic acid) diammonium salt), dpph (2,2-diphenyl-1-picrylhydrazyl) and galvinoxyl radicals as trolox (a vitamin e analogue) equivalent antioxidant capability (teac). the results showed that, whereas 1 did not exhibit radical scavenging activity, 2 resulted more active than trolox against the abts•+ radical (ec50 30.83 μm) and 3 displayed better antioxidant activity than trolox against abts•+, dpph and galvinoxyl radicals (ec50 values of 39.98, 150.99 and 13.19 μm, respectively). it is likely that such differences in antioxidant activity may rely on the differences in the relative positions of hydroxy groups [31] . then, compound 3, which showed the best scavenging activity, was evaluated for its primary antioxidant capacity. in this step, three reaction mechanisms were considered: single electron transfer (set), hydrogen transfer (ht) and radical adduct formation (raf), involving •ooh, •ooch3 and •ch(oh)ch3 as radicals. these experiments were carried out in lipidic and aqueous media, in order to mimic membrane and intra-cellular environment [32] , [33] . the results indicated that different mechanisms are involved depending by the medium and that positions 4, 7 and 8 of compound 3 are probably involved in ht mechanism, whereas positions 3, 4, 5 and 7 could be involved in raf mechanism. finally, the secondary antioxidant activity of compound 3 in aqueous media at physiological ph was evaluated. in the haber-weiss reaction (i.e., the reduction of copper in aqueous media and subsequent copper-catalyzed hydroxy radical formation), 3 was able to inhibit copper (ii) reduction avoiding oxidative stress. it was found that hydroxy groups in position 7 and 8 are fundamental for the primary and secondary antioxidant activity in both lipid and aqueous media. recently, wang and co-workers investigated the antioxidant activity and the mechanism of the antiradical action of six coumarin-fused coumarins (4-9, figure 4 ) previously synthesized by xi and liu [34, 35] . firstly, the scavenging activity of the compounds was evaluated on abts (2,2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), dpph (2,2-diphenyl-1-picrylhydrazyl) and galvinoxyl radicals as trolox (a vitamin e analogue) equivalent antioxidant capability (teac). the results showed that, whereas 1 did not exhibit radical scavenging activity, 2 resulted more active than trolox against the abts•+ radical (ec 50 30 .83 µm) and 3 displayed better antioxidant activity than trolox against abts•+, dpph and galvinoxyl radicals (ec 50 values of 39.98, 150.99 and 13.19 µm, respectively). it is likely that such differences in antioxidant activity may rely on the differences in the relative positions of hydroxy groups [31] . then, compound 3, which showed the best scavenging activity, was evaluated for its primary antioxidant capacity. in this step, three reaction mechanisms were considered: single electron transfer (set), hydrogen transfer (ht) and radical adduct formation (raf), involving •ooh, •ooch 3 and •ch(oh)ch 3 as radicals. these experiments were carried out in lipidic and aqueous media, in order to mimic membrane and intra-cellular environment [32] , [33] . the results indicated that different mechanisms are involved depending by the medium and that positions 4, 7 and 8 of compound 3 are probably involved in ht mechanism, whereas positions 3, 4, 5 and 7 could be involved in raf mechanism. finally, the secondary antioxidant activity of compound 3 in aqueous media at physiological ph was evaluated. in the haber-weiss reaction (i.e., the reduction of copper in aqueous media and subsequent copper-catalyzed hydroxy radical formation), 3 was able to inhibit copper (ii) reduction avoiding oxidative stress. it was found that hydroxy groups in position 7 and 8 are fundamental for the primary and secondary antioxidant activity in both lipid and aqueous media. recently, wang and co-workers investigated the antioxidant activity and the mechanism of the density functional theory (dft) calculations were performed, followed by the examination of the primary mechanisms, including ht, electron transfer-proton transfer (set-pt) and sequential proton loss transfer (splet). the most stable conformation of all the compounds was a non-planar structure, due to the steric repulsion of the groups in positions 5 and 5′. such conformation was retained by the correspondent anions and cation radicals (aro − , aroh +• ). ht process resulted the most significant in gas or non-polar phase, where compound 9 showed the highest activity. the ht path was possible for compounds 7, 8 and 9, having two or three oh groups, whereas 4 resulted inactive due to the absence of oh groups; compound 5, with only the 6-oh group, was less active than other compounds and 6 could merely trap dpph radical with a small rate constant. a second hat process was possible only for compound 9 and this finding could explain the higher activity of this molecule. in polar media, splet mechanism was favored-in this case the studied compounds were more efficient than trolox in the deprotonation step and, among them, compound 7 resulted to be the most promising, being more prone than the other compounds to deprotonate in a polar environment. the antioxidant potential of coumarin nucleus can be exploited in the production of new hybrid compound with enhanced antioxidant activity. a recent example of this strategy is the synthesis of a new series of chitosan derivatives (10a-d, figure 5 ) containing the coumarin nucleus, achieved by li and collaborators [36] . the antioxidant potential of compounds 10a-d was investigated by evaluating the inhibition of lipid peroxidation, metal ion chelation and free-radical scavenging activity. since both chitosan and coumarins have antioxidant properties themselves, the synthesized compounds were expected to show a stronger activity. lipid peroxidation inhibition was determined by quantifying thiobarbituric acid-reactive substance (tbars), using linoleic acid as a reference compound [37] . the results displayed the ability of the synthesized molecules to inhibit tabrs in a concentration-dependent manner; compound 10d emerged as the most active (ic50 = 0.11 mg/ml), showing a more efficient scavenging activity than chitosan alone (ic50 = 0.38 mg/ml). then, the radical-scavenging activity was the antioxidant potential of compounds 10a-d was investigated by evaluating the inhibition of lipid peroxidation, metal ion chelation and free-radical scavenging activity. since both chitosan and coumarins have antioxidant properties themselves, the synthesized compounds were expected to show a stronger activity. lipid peroxidation inhibition was determined by quantifying thiobarbituric evaluated. for this purpose, free radicals •oh, dpph and o2• − were used. compounds 10a-d showed a stronger •oh scavenging activity (ic50 = 0.09-0.12 mg/ml) compared to that of chitosan. these results suggested that the coumarin moiety strongly enhances chitosan antioxidant properties. since the chelating ability of antioxidants prevents oxidative stress by avoiding •oh production, iron-chelating properties of the new compounds were also evaluated through measurements of inhibition of ferrozine-fe 2+ complex formation. again, the obtained results (ic50 = 0.02-0.04 mg/ml) were better than those of chitosan alone. finally, cytotoxicity of the synthesized compounds was tested: no toxic effects were detected on 3t3-l1 and hhl-5 cells. interestingly, 3t3-l1 cells showed an increase in their viability, probably because of the antioxidant activity of the tested compounds. a similar approach was followed by popova and co-workers, who designed and synthesized a series of 4-methylcoumarins with tert-butyl, isobornyl and isocamphyl substituents (11, 12, 13-17, figure 6 ) [38] . the synthesized compounds were evaluated in terms of antioxidant, membrane-protective (mpa) and radical-scavenging (rsa) activities in vitro. all the tested compounds, at a concentration of 100 μm, exhibited good inhibitory activity against lipid peroxidation products (lpo) formation (ic50 = 3.33 -7.12 nm), whereas 7-hydroxy-4-methylcoumarin, used as reference compound, showed no activity. the scavenging activity, evaluated using dpph, strictly depended on the structure: only isobornyl derivatives showed moderate activity in the dpph assay (compound 15 showed rsa% = 57.48 ± 0.60 at 100 μm; rsa% = 87.95 ± 0.22 at 500 μm). moreover, the protective activity towards cell membrane was assessed, measuring the inhibitory activity against h2o2-induced hemolysis of red blood cells (rbcs). in all the experiments, the most promising compound was 15, having two isobornyl moieties. from these studies, it appears clear that coumarin derivatives show a great potential as antioxidant, membrane-protective and radical-scavenging compounds and that their activity depends mainly on the number and the position of the hydroxy groups. the term "cancer" defines a wide range of diseases caused by the accumulation of mutations and characterized by a multi-step process, involving many different factors which may not directly cause cancer themselves but can increase the chances of genetic mutations [39, 40] . recently, maleki et al. have synthesized eighteen o-prenylated coumarin derivatives and tested them on hela cervical cancer and hdf normal cells by mtt assay [41] . the most promising compounds are reported in figure 7 . the synthesized compounds were evaluated in terms of antioxidant, membrane-protective (mpa) and radical-scavenging (rsa) activities in vitro. all the tested compounds, at a concentration of 100 µm, exhibited good inhibitory activity against lipid peroxidation products (lpo) formation (ic 50 = 3.33-7.12 nm), whereas 7-hydroxy-4-methylcoumarin, used as reference compound, showed no activity. the scavenging activity, evaluated using dpph, strictly depended on the structure: only isobornyl derivatives showed moderate activity in the dpph assay (compound 15 showed rsa% = 57.48 ± 0.60 at 100 µm; rsa% = 87.95 ± 0.22 at 500 µm). moreover, the protective activity towards cell membrane was assessed, measuring the inhibitory activity against h 2 o 2 -induced hemolysis of red blood cells (rbcs). in all the experiments, the most promising compound was 15, having two isobornyl moieties. from these studies, it appears clear that coumarin derivatives show a great potential as antioxidant, membrane-protective and radical-scavenging compounds and that their activity depends mainly on the number and the position of the hydroxy groups. the term "cancer" defines a wide range of diseases caused by the accumulation of mutations and characterized by a multi-step process, involving many different factors which may not directly cause cancer themselves but can increase the chances of genetic mutations [39, 40] . recently, maleki et al. have synthesized eighteen o-prenylated coumarin derivatives and tested them on hela cervical cancer and hdf normal cells by mtt assay [41] . the most promising compounds are reported in figure 7 . the results represent a good starting point for the design of novel derivatives, because most of the examined compounds exhibited selective toxicity on hela cells (ic50 values between 136.4 ± 1.90 μm and 172.2 ± 1.80 μm after 24 h), whereas no negative effects on hdf normal cell's growth was detected. sar studies proved that the substitution on c6 position of coumarin nucleus provided the best anticancer activity, followed by substitution on c8. in addition, it was found that the cytotoxic properties of o-prenylated coumarins depends on the length of the prenyl chain, which increases the lipophilicity of the molecule, thus facilitating its penetration into the cells. the cytotoxic activity of prenylated-coumarin derivatives had been evaluated also by other groups. recent studies have shown a functional role of lipoxygenases (loxs) in carcinogenesis, precisely in prostatic cancer and the capability of 5-farnesyloxycoumarin (18, figure 8 ) to inhibit 15-lox-1 [42] [43] [44] starting from these observations, orafaie and collaborators investigated the inhibitory activity of compound 18 on 15-lox-1 [45] . the cytotoxic effects of 18 were evaluated by means of mtt assay on two carcinoma cell lines (pc-3 and du145) and a normal cell line (hff3), using 4-mmpb (4methyl-2-(4-methylpiperazinyl) pyrimido [4,5-b] benzothiazine) as reference compound. when pc3 and du145 human pca cells were treated with different concentrations of both 4-mmpb and 18 for 24, 48 and 72 h, a dose-dependent and time-dependent decrease in the survival of the cells was exhibited. pc3 cells resulted to be more sensitive than du145 cells to both inhibitors (ic50 in μg/ml for compound 18 on pc3 cells: 24 h, 40 19.52 ± 4.92) . moreover, compound 18 had no significant anti-proliferative activity on normal cells. concerning the mechanism of action, it was found that 5-farnesyloxycoumarin acts as a cytotoxic agent causing chromatin condensation and dna damage and induces the arrest of the cell cycle in g0/g1 phase. a similar study was carried out on 8-farnesyloxycoumarin (19, figure 8 ) by hosseinymehr and collaborators [46] . again, the coumarin derivative showed inhibitory activity on 15-lox-1 in pc3 and du145 cell lines, thus inducing apoptosis of the cancer cell, with the same mechanism of the results represent a good starting point for the design of novel derivatives, because most of the examined compounds exhibited selective toxicity on hela cells (ic 50 values between 136.4 ± 1.90 µm and 172.2 ± 1.80 µm after 24 h), whereas no negative effects on hdf normal cell's growth was detected. sar studies proved that the substitution on c6 position of coumarin nucleus provided the best anticancer activity, followed by substitution on c8. in addition, it was found that the cytotoxic properties of o-prenylated coumarins depends on the length of the prenyl chain, which increases the lipophilicity of the molecule, thus facilitating its penetration into the cells. the cytotoxic activity of prenylated-coumarin derivatives had been evaluated also by other groups. recent studies have shown a functional role of lipoxygenases (loxs) in carcinogenesis, precisely in prostatic cancer and the capability of 5-farnesyloxycoumarin (18, figure 8 ) to inhibit 15-lox-1 [42] [43] [44] . the results represent a good starting point for the design of novel derivatives, because most of the examined compounds exhibited selective toxicity on hela cells (ic50 values between 136.4 ± 1.90 μm and 172.2 ± 1.80 μm after 24 h), whereas no negative effects on hdf normal cell's growth was detected. sar studies proved that the substitution on c6 position of coumarin nucleus provided the best anticancer activity, followed by substitution on c8. in addition, it was found that the cytotoxic properties of o-prenylated coumarins depends on the length of the prenyl chain, which increases the lipophilicity of the molecule, thus facilitating its penetration into the cells. the cytotoxic activity of prenylated-coumarin derivatives had been evaluated also by other groups. recent studies have shown a functional role of lipoxygenases (loxs) in carcinogenesis, precisely in prostatic cancer and the capability of 5-farnesyloxycoumarin (18, figure 8 ) to inhibit 15-lox-1 [42] [43] [44] starting from these observations, orafaie and collaborators investigated the inhibitory activity of compound 18 on 15-lox-1 [45] . the cytotoxic effects of 18 were evaluated by means of mtt assay on two carcinoma cell lines (pc-3 and du145) and a normal cell line (hff3), using 4-mmpb (4methyl-2-(4-methylpiperazinyl) pyrimido [4,5-b] benzothiazine) as reference compound. when pc3 and du145 human pca cells were treated with different concentrations of both 4-mmpb and 18 for 24, 48 and 72 h, a dose-dependent and time-dependent decrease in the survival of the cells was exhibited. pc3 cells resulted to be more sensitive than du145 cells to both inhibitors (ic50 in μg/ml for compound 18 on pc3 cells: 24 h, 40 19.52 ± 4.92) . moreover, compound 18 had no significant anti-proliferative activity on normal cells. concerning the mechanism of action, it was found that 5-farnesyloxycoumarin acts as a cytotoxic agent causing chromatin condensation and dna damage and induces the arrest of the cell cycle in g0/g1 phase. a similar study was carried out on 8-farnesyloxycoumarin (19, figure 8 ) by hosseinymehr and collaborators [46] . again, the coumarin derivative showed inhibitory activity on 15-lox-1 in pc3 and du145 cell lines, thus inducing apoptosis of the cancer cell, with the same mechanism of starting from these observations, orafaie and collaborators investigated the inhibitory activity of compound 18 on 15-lox-1 [45] . the cytotoxic effects of 18 were evaluated by means of mtt assay on two carcinoma cell lines (pc-3 and du145) and a normal cell line (hff3), using 4-mmpb (4-methyl-2-(4-methylpiperazinyl) pyrimido [4,5-b] concerning the mechanism of action, it was found that 5-farnesyloxycoumarin acts as a cytotoxic agent causing chromatin condensation and dna damage and induces the arrest of the cell cycle in g 0 /g 1 phase. a similar study was carried out on 8-farnesyloxycoumarin (19, figure 8 ) by hosseinymehr and collaborators [46] . again, the coumarin derivative showed inhibitory activity on 15-lox-1 in pc3 and du145 cell lines, thus inducing apoptosis of the cancer cell, with the same mechanism of compound 18. pc3 cells resulted to be more sensitive to 19 inhibition than du145 cells; ic 50 halawa et al. synthesized and characterized a new series of 4-arylamino-3-nitrocoumarin analogues from 4-hydroxycoumarin and tested them on the human cervix carcinoma cell line kb-3-1 [47] . these compounds were found to target the dna-topo i (human topoisomerase i) complex, thus blocking cell replication and leading to cell death. among this series, thiazolidinylidene derivative 20 ( figure 9 ) containing a malononitrile fragment exhibited the best cytotoxic activity with an ic 50 value of 21 µm. the cytotoxicity of 20 was explained also by docking studies which highlighted that it forms important h-bonds with arg364, asp533, gln633 and 5 -thio-2 deoxyguanosine phosphonic acid of the dna backbone. [47] . these compounds were found to target the dna-topo i (human topoisomerase i) complex, thus blocking cell replication and leading to cell death. among this series, thiazolidinylidene derivative 20 ( figure 9 ) containing a malononitrile fragment exhibited the best cytotoxic activity with an ic50 value of 21 μm. the cytotoxicity of 20 was explained also by docking studies which highlighted that it forms important h-bonds with arg364, asp533, gln633 and 5′-thio-2′ deoxyguanosine phosphonic acid of the dna backbone. herrera et al. synthesized a series of 3-and 7-styrylcoumarins, some of which showed antiproliferative activity on sw480 human colon adenocarcinoma cells [48] . among them, 7-(4-hydroxy-3,5-dimethoxystyryl)-2h-chromen-2-one (21, figure 10 ) showed the highest activity (ic50 = 1.01 μm) as it was capable of inducing apoptosis in sw480 cells, probably by modulating the tumor-suppressor protein p53. the new compound was also tested in vivo, demonstrating to be able to inhibit the early progression of colon adenocarcinoma [49] . as coumarin nucleus can be widely decorated, it can be used in the synthesis of hybrid compounds, targeting different proteins involved not only in tumor growth but also in metastatic and angiogenetic processes. in this context, diao and collaborators synthesized a series of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives (22a-l, figure 11 ) [50] . several isatin-based or 1,2,3-triazole or coumarin-based compounds (semaxanib, carboxyamidotriazole and stx64) are involved in clinical trials or have already been used the treatment of various cancers (as colon-rectal, prostatic, endometrial and breast cancer) [51, 52] , whereas isatin-1,2,3-triazole-coumarin derivatives showed activity against different cancer types. in addition, sar studies demonstrated that the linker between isatin and 1,2,3-triazole influences the activity [52, 53] and that hydrogen bonds are fundamental for the biological activity [54] . these evidences guided diao and collaborators in the choice of diethylene glycol as a linker [47] . ten compounds were tested on hepg2 (liver carcinoma), hela (cervical cancer), a549 (lung adenocarcinoma), du145 (prostatic cancer), skov3 (ovarian carcinoma), mcf-7 (breast cancer) and drug-resistant mcf-7/dox (doxorubicin-resistant mcf-7) herrera et al. synthesized a series of 3-and 7-styrylcoumarins, some of which showed anti-proliferative activity on sw480 human colon adenocarcinoma cells [48] . among them, 7-(4-hydroxy-3,5-dimethoxystyryl)-2h-chromen-2-one (21, figure 10 ) showed the highest activity (ic 50 = 1.01 µm) as it was capable of inducing apoptosis in sw480 cells, probably by modulating the tumor-suppressor protein p53. the new compound was also tested in vivo, demonstrating to be able to inhibit the early progression of colon adenocarcinoma [49] . [47] . these compounds were found to target the dna-topo i (human topoisomerase i) complex, thus blocking cell replication and leading to cell death. among this series, thiazolidinylidene derivative 20 ( figure 9 ) containing a malononitrile fragment exhibited the best cytotoxic activity with an ic50 value of 21 μm. the cytotoxicity of 20 was explained also by docking studies which highlighted that it forms important h-bonds with arg364, asp533, gln633 and 5′-thio-2′ deoxyguanosine phosphonic acid of the dna backbone. herrera et al. synthesized a series of 3-and 7-styrylcoumarins, some of which showed antiproliferative activity on sw480 human colon adenocarcinoma cells [48] . among them, 7-(4-hydroxy-3,5-dimethoxystyryl)-2h-chromen-2-one (21, figure 10 ) showed the highest activity (ic50 = 1.01 μm) as it was capable of inducing apoptosis in sw480 cells, probably by modulating the tumor-suppressor protein p53. the new compound was also tested in vivo, demonstrating to be able to inhibit the early progression of colon adenocarcinoma [49] . as coumarin nucleus can be widely decorated, it can be used in the synthesis of hybrid compounds, targeting different proteins involved not only in tumor growth but also in metastatic and angiogenetic processes. in this context, diao and collaborators synthesized a series of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives (22a-l, figure 11 ) [50] . several isatin-based or 1,2,3-triazole or coumarin-based compounds (semaxanib, carboxyamidotriazole and stx64) are involved in clinical trials or have already been used the treatment of various cancers (as colon-rectal, prostatic, endometrial and breast cancer) [51, 52] , whereas isatin-1,2,3-triazole-coumarin derivatives showed activity against different cancer types. in addition, sar studies demonstrated that the linker between isatin and 1,2,3-triazole influences the activity [52, 53] and that hydrogen bonds are fundamental for the biological activity [54] . these evidences guided diao and collaborators in the choice of diethylene glycol as a linker [47] . ten compounds were tested on hepg2 (liver carcinoma), hela (cervical cancer), a549 (lung adenocarcinoma), du145 (prostatic cancer), skov3 (ovarian carcinoma), mcf-7 (breast cancer) and drug-resistant mcf-7/dox (doxorubicin-resistant mcf-7) as coumarin nucleus can be widely decorated, it can be used in the synthesis of hybrid compounds, targeting different proteins involved not only in tumor growth but also in metastatic and angiogenetic processes. in this context, diao and collaborators synthesized a series of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives (22a-l, figure 11 ) [50] . several isatin-based or 1,2,3-triazole or coumarin-based compounds (semaxanib, carboxyamidotriazole and stx64) are involved in clinical trials or have already been used the treatment of various cancers (as colon-rectal, prostatic, endometrial and breast cancer) [51, 52] , whereas isatin-1,2,3-triazole-coumarin derivatives showed activity against different cancer types. in addition, sar studies demonstrated that the linker between isatin and 1,2,3-triazole influences the activity [52, 53] and that hydrogen bonds are fundamental for the biological activity [54] . these evidences guided diao and collaborators in the choice of diethylene glycol as a linker [47] . ten compounds were tested on hepg2 (liver carcinoma), hela (cervical cancer), a549 (lung adenocarcinoma), du145 (prostatic cancer), skov3 (ovarian carcinoma), mcf-7 (breast cancer) and drug-resistant mcf-7/dox (doxorubicin-resistant mcf-7) human cancer cell lines. all the synthesized compounds showed weak to moderate in vitro activity against all the cell lines, therefore further sar studies are necessary for the obtainment of new, more active compounds. human cancer cell lines. all the synthesized compounds showed weak to moderate in vitro activity against all the cell lines, therefore further sar studies are necessary for the obtainment of new, more active compounds. figure 11 . general structure of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives 22a-l. cai et al. developed a series of fluorescent coumarin-benzo[b]thiophene 1, 1-dioxide conjugates [55] . these compounds act on stat3, which is involved in the regulation of mitochondrial apoptotic pathway [56] . in particular, they hypothesized that the inhibition of phosphorylation of tyr705 and ser727 might prevent stat3 activation. four stat3 over-activated human cancer cell lines (i.e., human breast carcinoma mda-mb-231 and mcf-7 cells, human colonic carcinoma hct-116 cells and human hepatocellular carcinoma hepg2 cells) were selected to assess the biological activity of the newly-synthesized compounds. compound 23 ( figure 12 ) showed high potency in inducing cancer cell apoptosis and ros generation, inhibiting stat3 phosphorylation on tyr705, affecting mitochondrial membrane potential and preventing stat3 dna-binding activity. in addition, 23 inhibited implanted 4t1 breast cancer growth in vivo. the antiproliferative effects of compound 23 on normal cells were investigated by mtt assays comparing it to the stat3 inhibitor stattic, which showed growth inhibition activity in both tumor and normal cells, whereas compound 23 exhibited selective inhibitory activity against cancer cells (ic50 14.62 μm for mcf-10a cells and ic50 35.60 μm for l02 cells), indicating a higher selectivity than stattic. carbonic anhydrases (cas) are ubiquitous metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate and protons, which is an essential physiological reaction [57] . thus, this enzyme is involved in a wide range of physiological and pathological processes (ph regulation, co2 homeostasis, respiration, bone resorption and tumorigenesis) [58] and its deregulation by means of carbonic anhydrases inhibitors (cais) may be useful in the treatment of many disorders [59] [60] [61] . the ideal ca inhibitor would selectively act against those isoforms (hca ix, xii, for instance) related to a certain disease [62, 63] . in this context, coumarins emerged as potential figure 11 . general structure of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives 22a-l. cai et al. developed a series of fluorescent coumarin-benzo[b]thiophene 1, 1-dioxide conjugates [55] . these compounds act on stat3, which is involved in the regulation of mitochondrial apoptotic pathway [56] . in particular, they hypothesized that the inhibition of phosphorylation of tyr705 and ser727 might prevent stat3 activation. four stat3 over-activated human cancer cell lines (i.e., human breast carcinoma mda-mb-231 and mcf-7 cells, human colonic carcinoma hct-116 cells and human hepatocellular carcinoma hepg2 cells) were selected to assess the biological activity of the newly-synthesized compounds. compound 23 ( figure 12 ) showed high potency in inducing cancer cell apoptosis and ros generation, inhibiting stat3 phosphorylation on tyr705, affecting mitochondrial membrane potential and preventing stat3 dna-binding activity. in addition, 23 inhibited implanted 4t1 breast cancer growth in vivo. the antiproliferative effects of compound 23 on normal cells were investigated by mtt assays comparing it to the stat3 inhibitor stattic, which showed growth inhibition activity in both tumor and normal cells, whereas compound 23 exhibited selective inhibitory activity against cancer cells (ic 50 human cancer cell lines. all the synthesized compounds showed weak to moderate in vitro activity against all the cell lines, therefore further sar studies are necessary for the obtainment of new, more active compounds. figure 11 . general structure of diethylene glycol tethered isatin-1,2,3-triazole-coumarin derivatives 22a-l. cai et al. developed a series of fluorescent coumarin-benzo[b]thiophene 1, 1-dioxide conjugates [55] . these compounds act on stat3, which is involved in the regulation of mitochondrial apoptotic pathway [56] . in particular, they hypothesized that the inhibition of phosphorylation of tyr705 and ser727 might prevent stat3 activation. four stat3 over-activated human cancer cell lines (i.e., human breast carcinoma mda-mb-231 and mcf-7 cells, human colonic carcinoma hct-116 cells and human hepatocellular carcinoma hepg2 cells) were selected to assess the biological activity of the newly-synthesized compounds. compound 23 ( figure 12 ) showed high potency in inducing cancer cell apoptosis and ros generation, inhibiting stat3 phosphorylation on tyr705, affecting mitochondrial membrane potential and preventing stat3 dna-binding activity. in addition, 23 inhibited implanted 4t1 breast cancer growth in vivo. the antiproliferative effects of compound 23 on normal cells were investigated by mtt assays comparing it to the stat3 inhibitor stattic, which showed growth inhibition activity in both tumor and normal cells, whereas compound 23 exhibited selective inhibitory activity against cancer cells (ic50 14.62 μm for mcf-10a cells and ic50 35.60 μm for l02 cells), indicating a higher selectivity than stattic. carbonic anhydrases (cas) are ubiquitous metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate and protons, which is an essential physiological reaction [57] . thus, this enzyme is involved in a wide range of physiological and pathological processes (ph regulation, co2 homeostasis, respiration, bone resorption and tumorigenesis) [58] and its deregulation by means of carbonic anhydrases inhibitors (cais) may be useful in the treatment of many disorders [59] [60] [61] . the ideal ca inhibitor would selectively act against those isoforms (hca ix, xii, for instance) related to a certain disease [62, 63] . in this context, coumarins emerged as potential carbonic anhydrases (cas) are ubiquitous metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate and protons, which is an essential physiological reaction [57] . thus, this enzyme is involved in a wide range of physiological and pathological processes (ph regulation, co 2 homeostasis, respiration, bone resorption and tumorigenesis) [58] and its deregulation by means of carbonic anhydrases inhibitors (cais) may be useful in the treatment of many disorders [59] [60] [61] . the ideal ca inhibitor would selectively act against those isoforms (hca ix, xii, for instance) related to a certain disease [62, 63] . in this context, coumarins emerged as potential atypical hca ligands that, unlike classical hcais, do not need to chelate the prosthetic zinc ion but, after binding the catalytic site, are hydrolyzed to the corresponding 2-hydroxy cinnamic acid derivatives, the actual inhibitors [64, 65] . some studies highlighted that coumarins are capable of binding at the entrance of hca catalytic site, blocking the enzyme activity. furthermore, 7-hydroxycoumarins derivatives showed good selectivity toward ix and xii isoforms over hca i and ii and, in some cases, they exhibited cytotoxic activity on cancer cells [66] [67] [68] [69] . many efforts have been made in this direction and the most recent results are here reported. fois and collaborators have recently investigated the selective inhibitory activity towards ca ix and ca xii of extracts of magydaris pastiacea seeds, from which they isolated ten linear furocoumarins, four simple coumarins and a new angular dihydrofurocoumarin [70] all the mentioned compounds were tested against four isoforms of hca: both extracts showed selective activity towards ca ix and xii whereas no effect was seen on isoforms i and ii at a concentration of 100 ng/ml. the most promising compound was umbelliprenin (24, figure 13 ), highly active (k i = 5.8 nm) against ca xii and highly selective over isoforms i and ii. atypical hca ligands that, unlike classical hcais, do not need to chelate the prosthetic zinc ion but, after binding the catalytic site, are hydrolyzed to the corresponding 2-hydroxy cinnamic acid derivatives, the actual inhibitors [64, 65] . some studies highlighted that coumarins are capable of binding at the entrance of hca catalytic site, blocking the enzyme activity. furthermore, 7hydroxycoumarins derivatives showed good selectivity toward ix and xii isoforms over hca i and ii and, in some cases, they exhibited cytotoxic activity on cancer cells [66] [67] [68] [69] . many efforts have been made in this direction and the most recent results are here reported. fois and collaborators have recently investigated the selective inhibitory activity towards ca ix and ca xii of extracts of magydaris pastiacea seeds, from which they isolated ten linear furocoumarins, four simple coumarins and a new angular dihydrofurocoumarin [70] all the mentioned compounds were tested against four isoforms of hca: both extracts showed selective activity towards ca ix and xii whereas no effect was seen on isoforms i and ii at a concentration of 100 ng/ml. the most promising compound was umbelliprenin (24, figure 13 ), highly active (ki = 5.8 nm) against ca xii and highly selective over isoforms i and ii. umbelliprenin (24) was then tested on hela cancer cells in order to evaluate its cytotoxic activity and resulted to possess a moderate cytotoxicity (ic50 =75 μm) proving to be able to inhibit tumor growth, angiogenesis and metastasis formation in mice (after i.p. administration). it is noteworthy that ca ix and xii are overexpressed in tumor cells under hypoxic conditions, whereas the mentioned tests were carried out under normoxic conditions, which could explain the moderate cytotoxic activity of the isolated compound. in 2019, starting from 4-methylumbelliferone (25, figure 14 ), buran and co-workers synthesized a series of 8-substituted coumarin-based compounds bearing alkylpiperazine and arylpiperazine chains (26-37, figure 14 ), and evaluated their inhibitory activity against hca i, ii, ix and xii [71] . all the tested compounds were able to inhibit hca isoforms ix and xii, without showing any inhibitory activity towards the cytosolic isoforms i and ii up to a 10 μm concentration. the test pointed out that these compounds had higher affinity for hca xii over ix and, except for compound 36 (ki (hca xii) = 26.4 nm), they all had ki values comparable to those of the reference drug acetazolamide (ki (hca xii) = 5.7 nm). it is remarkable that the substitution of c8 position of 4-methylumbelliferone (25) umbelliprenin (24) was then tested on hela cancer cells in order to evaluate its cytotoxic activity and resulted to possess a moderate cytotoxicity (ic 50 = 75 µm) proving to be able to inhibit tumor growth, angiogenesis and metastasis formation in mice (after i.p. administration). it is noteworthy that ca ix and xii are overexpressed in tumor cells under hypoxic conditions, whereas the mentioned tests were carried out under normoxic conditions, which could explain the moderate cytotoxic activity of the isolated compound. in 2019, starting from 4-methylumbelliferone (25, figure 14 ), buran and co-workers synthesized a series of 8-substituted coumarin-based compounds bearing alkylpiperazine and arylpiperazine chains (26-37, figure 14 ), and evaluated their inhibitory activity against hca i, ii, ix and xii [71] . all the tested compounds were able to inhibit hca isoforms ix and xii, without showing any inhibitory activity towards the cytosolic isoforms i and ii up to a 10 µm concentration. the test pointed out that these compounds had higher affinity for hca xii over ix and, except for compound 36 (k i (hca xii) = 26.4 nm), they all had k i values comparable to those of the reference drug acetazolamide (k i (hca xii) = 5.7 nm). atypical hca ligands that, unlike classical hcais, do not need to chelate the prosthetic zinc ion but, after binding the catalytic site, are hydrolyzed to the corresponding 2-hydroxy cinnamic acid derivatives, the actual inhibitors [64, 65] . some studies highlighted that coumarins are capable of binding at the entrance of hca catalytic site, blocking the enzyme activity. furthermore, 7hydroxycoumarins derivatives showed good selectivity toward ix and xii isoforms over hca i and ii and, in some cases, they exhibited cytotoxic activity on cancer cells [66] [67] [68] [69] . many efforts have been made in this direction and the most recent results are here reported. fois and collaborators have recently investigated the selective inhibitory activity towards ca ix and ca xii of extracts of magydaris pastiacea seeds, from which they isolated ten linear furocoumarins, four simple coumarins and a new angular dihydrofurocoumarin [70] all the mentioned compounds were tested against four isoforms of hca: both extracts showed selective activity towards ca ix and xii whereas no effect was seen on isoforms i and ii at a concentration of 100 ng/ml. the most promising compound was umbelliprenin (24, figure 13 ), highly active (ki = 5.8 nm) against ca xii and highly selective over isoforms i and ii. umbelliprenin (24) was then tested on hela cancer cells in order to evaluate its cytotoxic activity and resulted to possess a moderate cytotoxicity (ic50 =75 μm) proving to be able to inhibit tumor growth, angiogenesis and metastasis formation in mice (after i.p. administration). it is noteworthy that ca ix and xii are overexpressed in tumor cells under hypoxic conditions, whereas the mentioned tests were carried out under normoxic conditions, which could explain the moderate cytotoxic activity of the isolated compound. in 2019, starting from 4-methylumbelliferone (25, figure 14 ), buran and co-workers synthesized a series of 8-substituted coumarin-based compounds bearing alkylpiperazine and arylpiperazine chains (26-37, figure 14 ), and evaluated their inhibitory activity against hca i, ii, ix and xii [71] . all the tested compounds were able to inhibit hca isoforms ix and xii, without showing any inhibitory activity towards the cytosolic isoforms i and ii up to a 10 μm concentration. the test pointed out that these compounds had higher affinity for hca xii over ix and, except for compound 36 (ki (hca xii) = 26.4 nm), they all had ki values comparable to those of the reference drug acetazolamide (ki (hca xii) = 5.7 nm). it is remarkable that the substitution of c8 position of 4-methylumbelliferone (25) it is remarkable that the substitution of c8 position of 4-methylumbelliferone (25) did not have any influence on inhibition of hca xii, suggesting that no significant interaction may be achieved between the side chains of compounds 26-37 and the catalytic site of isoform xii. on the other hand, alkylpiperazine derivatives showed better activity on hca ix when compared with the other synthesized compounds, being compound 30 the one with the highest activity among them (ic 50 = 27.1 nm). similar results were obtained by many other groups that have recently synthesized coumarin-based compounds and evaluated them as hca ix and xii inhibitors. sulphocumarins, bis-coumarins and coumarins 1,3,4-oxadiazole derivatives are some examples [72] [73] [74] . the battle against infections and multidrug resistant bacteria is almost certainly one of the most challenging issue that the scientific community and the whole mankind will face in the near future. multidrug resistant (mdr) bacteria are defined as non-susceptible strains to one or more antimicrobials on three or more antimicrobial classes, whereas strains that are non-susceptible to all antimicrobials are classified as extremely drug-resistant strains [75, 76] . the plant kingdom provides a virtually endless source of novel chemicals and scaffolds, such as polyphenols and coumarins [77] . in 2005, the antibacterial potency of nearly 50 coumarin derivatives, natural and synthetic, was evaluated and then correlated by a sar study. bacterial susceptibility to coumarins was evaluated by determining the minimal inhibitory concentration (mic) and minimum bactericidal concentration (mbc), considering active compounds exhibiting mic values ranging from 62.5 to 2000 µg/ml. among the active compounds, osthenole (a natural coumarin having also the anti-inflammatory activity) showed the most potent activity with a mic of 62.5 µg/ml against s. aureus and b. cereus [78] . in 2015, nagamallu and co-workers exploited the vilsmeier-haack reaction to obtain a series of novel pyrazole-containing coumarins and then evaluated their antioxidant and antibacterial activities [79] . among the series, two compounds (38 and 39, figure 15 ) showed a good antibacterial and antifungal activity, with mic values comparable with the ones of ciprofloxacin (positive control against bacteria species) and fluconazole (positive control against fungi strains). the battle against infections and multidrug resistant bacteria is almost certainly one of the most challenging issue that the scientific community and the whole mankind will face in the near future. multidrug resistant (mdr) bacteria are defined as non-susceptible strains to one or more antimicrobials on three or more antimicrobial classes, whereas strains that are non-susceptible to all antimicrobials are classified as extremely drug-resistant strains [75, 76] . the plant kingdom provides a virtually endless source of novel chemicals and scaffolds, such as polyphenols and coumarins [77] . in 2005, the antibacterial potency of nearly 50 coumarin derivatives, natural and synthetic, was evaluated and then correlated by a sar study. bacterial susceptibility to coumarins was evaluated by determining the minimal inhibitory concentration (mic) and minimum bactericidal concentration (mbc), considering active compounds exhibiting mic values ranging from 62.5 to 2000 μg/ml. among the active compounds, osthenole (a natural coumarin having also the anti-inflammatory activity) showed the most potent activity with a mic of 62.5 μg/ml against s. aureus and b. cereus [78] . in 2015, nagamallu and co-workers exploited the vilsmeier-haack reaction to obtain a series of novel pyrazole-containing coumarins and then evaluated their antioxidant and antibacterial activities [79] . among the series, two compounds (38 and 39, figure 15 ) showed a good antibacterial and antifungal activity, with mic values comparable with the ones of ciprofloxacin (positive control against bacteria species) and fluconazole (positive control against fungi strains). following the idea that the introduction of an additional coumarin nucleus on a parent coumarin molecule could improve the pharmacological activity (i.e., dicumarol as anticoagulant), in 2017, chougala and colleagues designed and synthesized a series of bis-coumarin derivatives [80] . figure 16 shows the common scaffolds of the bis-coumarins synthesized using l-proline as catalyst in a multi-component reaction approach. following the idea that the introduction of an additional coumarin nucleus on a parent coumarin molecule could improve the pharmacological activity (i.e., dicumarol as anticoagulant), in 2017, chougala and colleagues designed and synthesized a series of bis-coumarin derivatives [80] . figure 16 shows the common scaffolds of the bis-coumarins synthesized using l-proline as catalyst in a multi-component reaction approach. the antibacterial potency of the compounds was evaluated against gram-positive and gramnegative strains, comparing the mic with ciprofloxacin and most of the newly synthesized compounds showed modest to good inhibiting activity against the tested microorganisms. compounds 40a-e ( figure 16 ) were highly active and more potent than ciprofloxacin against s. aureus and e. faecalis, whereas 41c and 41d were active only against gram-positive e. faecalis. actually, compounds 41a-e were the most promising against e. coli. once established the broad spectrum of action of the coumarin nucleus, various researchers focused their attention on the activity against multidrug resistant strains, in particular on the eskape pathogens, the coterie that escape the lethal action of antibiotics: enterococcus faecium, staphylococcus aureus, klebsiella pneumoniae, acinetobacter baumanii, pseudomonas aeruginosa and enterobacter species [81] . in 2017, naik et al. synthesized and evaluated against s. aureus and other bacterial strains a series of 3,4-dihydropyrimidinone-coumarin analogues, measuring the mic values and comparing them to ciprofloxacin [82] . the structures and the mic values for compounds 42-49, the most promising derivatives, are reported in figure 17 : the substitution at c6 position seemed to be excellent for the activity and able to modulate the potency, decreasing the efficiency in the order of -ch3 > 7,8-benzo > -cl > -och3. furthermore, it was revealed from docking studies that that one hydrogen atom and two oxygen atoms of 3,4-dihydropyrimidinone substituted coumarins form interactions with the active site residues of s. aureus gyrase, indicating that the presence of hydrogen bond acceptor and donor groups may enhance antimicrobial activity. in 2018, chavan and hosamani proposed a facile method for the microwave assisted synthesis of a series of pyrazole-containing coumarins and tested their antibacterial and anti-inflammatory activities [83] . the researchers evaluated the in vitro antibacterial activity of the newly synthesized the antibacterial potency of the compounds was evaluated against gram-positive and gram-negative strains, comparing the mic with ciprofloxacin and most of the newly synthesized compounds showed modest to good inhibiting activity against the tested microorganisms. compounds 40a-e ( figure 16 ) were highly active and more potent than ciprofloxacin against s. aureus and e. faecalis, whereas 41c and 41d were active only against gram-positive e. faecalis. actually, compounds 41a-e were the most promising against e. coli. once established the broad spectrum of action of the coumarin nucleus, various researchers focused their attention on the activity against multidrug resistant strains, in particular on the eskape pathogens, the coterie that escape the lethal action of antibiotics: enterococcus faecium, staphylococcus aureus, klebsiella pneumoniae, acinetobacter baumanii, pseudomonas aeruginosa and enterobacter species [81] . in 2017, naik et al. synthesized and evaluated against s. aureus and other bacterial strains a series of 3,4-dihydropyrimidinone-coumarin analogues, measuring the mic values and comparing them to ciprofloxacin [82] . the structures and the mic values for compounds 42-49, the most promising derivatives, are reported in figure 17 : the substitution at c6 position seemed to be excellent for the activity and able to modulate the potency, decreasing the efficiency in the order of -ch 3 > 7,8-benzo > -cl > -och 3 . furthermore, it was revealed from docking studies that that one hydrogen atom and two oxygen atoms of 3,4-dihydropyrimidinone substituted coumarins form interactions with the active site residues of s. aureus gyrase, indicating that the presence of hydrogen bond acceptor and donor groups may enhance antimicrobial activity. the antibacterial potency of the compounds was evaluated against gram-positive and gramnegative strains, comparing the mic with ciprofloxacin and most of the newly synthesized compounds showed modest to good inhibiting activity against the tested microorganisms. compounds 40a-e ( figure 16 ) were highly active and more potent than ciprofloxacin against s. aureus and e. faecalis, whereas 41c and 41d were active only against gram-positive e. faecalis. actually, compounds 41a-e were the most promising against e. coli. once established the broad spectrum of action of the coumarin nucleus, various researchers focused their attention on the activity against multidrug resistant strains, in particular on the eskape pathogens, the coterie that escape the lethal action of antibiotics: enterococcus faecium, staphylococcus aureus, klebsiella pneumoniae, acinetobacter baumanii, pseudomonas aeruginosa and enterobacter species [81] . in 2017, naik et al. synthesized and evaluated against s. aureus and other bacterial strains a series of 3,4-dihydropyrimidinone-coumarin analogues, measuring the mic values and comparing them to ciprofloxacin [82] . the structures and the mic values for compounds 42-49, the most promising derivatives, are reported in figure 17 : the substitution at c6 position seemed to be excellent for the activity and able to modulate the potency, decreasing the efficiency in the order of -ch3 > 7,8-benzo > -cl > -och3. furthermore, it was revealed from docking studies that that one hydrogen atom and two oxygen atoms of 3,4-dihydropyrimidinone substituted coumarins form interactions with the active site residues of s. aureus gyrase, indicating that the presence of hydrogen bond acceptor and donor groups may enhance antimicrobial activity. in 2018, chavan and hosamani proposed a facile method for the microwave assisted synthesis of a series of pyrazole-containing coumarins and tested their antibacterial and anti-inflammatory activities [83] . the researchers evaluated the in vitro antibacterial activity of the newly synthesized in 2018, chavan and hosamani proposed a facile method for the microwave assisted synthesis of a series of pyrazole-containing coumarins and tested their antibacterial and anti-inflammatory activities [83] . the researchers evaluated the in vitro antibacterial activity of the newly synthesized compounds through agar-well diffusion method against two gram-positive (bacillus subtilis (atcc no. staphylococcus aureus (atcc-29213)) and two gram-negative (escherichia coli (atcc-25922) and pseudomonas aeruginosa (atcc no.25619)) bacterial strains [84] . the mic values were compared to those of ciprofloxacin and all the compounds showed significant antibacterial activity. in particular, compounds 50 and 51 ( figure 18 ), showed an excellent activity against s. aureus (mic 0.78 µg/ml and mic 1.562 µg/ml, respectively). docking studies were in good agreement with the biological results. compounds through agar-well diffusion method against two gram-positive (bacillus subtilis (atcc no. 23857) and staphylococcus aureus (atcc-29213)) and two gram-negative (escherichia coli (atcc-25922) and pseudomonas aeruginosa (atcc no.25619)) bacterial strains [84] . the mic values were compared to those of ciprofloxacin and all the compounds showed significant antibacterial activity. in particular, compounds 50 and 51 ( figure 18 ), showed an excellent activity against s. aureus (mic 0.78 μg/ml and mic 1.562 μg/ml, respectively). docking studies were in good agreement with the biological results. in 2017, madeiro and co-workers focalized their interest towards the antibiotic activity of coumarins isolated from rutacea species ( figure 19 ) [85] . bergapten, xantoxin, isopimpinellin and imperatorin did not exhibit any antibacterial activity, even at the highest concentration, against s. aureus strains resistant to tetracycline, erythromycin and norfloxacin. however, their role as modulator of other antibiotics seemed quite promising, because isopimpinellin and imperatorin reduced the mic of erythromycin, tetracycline and norfloxacin. nevertheless, more detailed research is necessary in order to enable the use of these natural products as adjuvants to antimicrobial agents. in 2018, widelsky and co-workers isolated some similar linear furanocoumarins from the fruits of peucedanum luxurians tamamsch, with more encouraging results. plants of the peucedanum genus have been used for centuries as antibacterial agents and, for some of them, the activity was confirmed by biological and pharmacological studies on plant extracts and on a few isolated compounds [86] . all the six isolated compounds showed a broad growth-inhibitor activity against several bacteria strains but three of them ( figure 20 ) resulted particularly interesting. 6′,7′-dihydroxybergamottin was the most active against all the bacteria strains tested, probably because of the aliphatic chain in c5 position; similar activity was noticed for peucedanin and officinalin isobutyrate. in 2017, madeiro and co-workers focalized their interest towards the antibiotic activity of coumarins isolated from rutacea species ( figure 19 ) [85] . bergapten, xantoxin, isopimpinellin and imperatorin did not exhibit any antibacterial activity, even at the highest concentration, against s. aureus strains resistant to tetracycline, erythromycin and norfloxacin. however, their role as modulator of other antibiotics seemed quite promising, because isopimpinellin and imperatorin reduced the mic of erythromycin, tetracycline and norfloxacin. nevertheless, more detailed research is necessary in order to enable the use of these natural products as adjuvants to antimicrobial agents. compounds through agar-well diffusion method against two gram-positive (bacillus subtilis (atcc no. 23857) and staphylococcus aureus (atcc-29213)) and two gram-negative (escherichia coli (atcc-25922) and pseudomonas aeruginosa (atcc no.25619)) bacterial strains [84] . the mic values were compared to those of ciprofloxacin and all the compounds showed significant antibacterial activity. in particular, compounds 50 and 51 ( figure 18 ), showed an excellent activity against s. aureus (mic 0.78 μg/ml and mic 1.562 μg/ml, respectively). docking studies were in good agreement with the biological results. in 2017, madeiro and co-workers focalized their interest towards the antibiotic activity of coumarins isolated from rutacea species ( figure 19 ) [85] . bergapten, xantoxin, isopimpinellin and imperatorin did not exhibit any antibacterial activity, even at the highest concentration, against s. aureus strains resistant to tetracycline, erythromycin and norfloxacin. however, their role as modulator of other antibiotics seemed quite promising, because isopimpinellin and imperatorin reduced the mic of erythromycin, tetracycline and norfloxacin. nevertheless, more detailed research is necessary in order to enable the use of these natural products as adjuvants to antimicrobial agents. in 2018, widelsky and co-workers isolated some similar linear furanocoumarins from the fruits of peucedanum luxurians tamamsch, with more encouraging results. plants of the peucedanum genus have been used for centuries as antibacterial agents and, for some of them, the activity was confirmed by biological and pharmacological studies on plant extracts and on a few isolated compounds [86] . all the six isolated compounds showed a broad growth-inhibitor activity against several bacteria strains but three of them ( figure 20 ) resulted particularly interesting. 6′,7′-dihydroxybergamottin was the most active against all the bacteria strains tested, probably because of the aliphatic chain in c5 position; similar activity was noticed for peucedanin and officinalin isobutyrate. in 2018, widelsky and co-workers isolated some similar linear furanocoumarins from the fruits of peucedanum luxurians tamamsch, with more encouraging results. plants of the peucedanum genus have been used for centuries as antibacterial agents and, for some of them, the activity was confirmed by biological and pharmacological studies on plant extracts and on a few isolated compounds [86] . all the six isolated compounds showed a broad growth-inhibitor activity against several bacteria strains but three of them ( figure 20 ) resulted particularly interesting. 6 ,7 -dihydroxybergamottin was the most active against all the bacteria strains tested, probably because of the aliphatic chain in c5 position; similar activity was noticed for peucedanin and officinalin isobutyrate. liu and colleagues made a huge effort to synthesize and identify coumarin-pyrazole carboxamide derivatives as potential topoisomerase-ii inhibitors: 70 novel compounds were obtained and evaluated [87] . three of them (52-54, figure 21 ) were endowed with promising antimicrobial activities. in particular, compound 52 showed a considerable inhibitory activity compared with ciprofloxacin against escherichia coli and compound 53 exhibited excellent antibacterial activity against salmonella typhi. the selected compounds exhibited also potent inhibition against topo ii and topo iv with ic50 values in the range 9.4-25 mg/l. fungal diseases are a well-known plague for animal and plant worlds but a more hidden menace for human health. more than 90% of all reported fungal-related deaths results from species that belong to one of four genera: cryptococcus, candida, aspergillus and pneumocystis [88] [89] [90] . coumarin derivatives are endowed with antifungal activity, potentially useful in both pharma and agri-food sectors. in this liu and colleagues made a huge effort to synthesize and identify coumarin-pyrazole carboxamide derivatives as potential topoisomerase-ii inhibitors: 70 novel compounds were obtained and evaluated [87] . three of them (52-54, figure 21 ) were endowed with promising antimicrobial activities. in particular, compound 52 showed a considerable inhibitory activity compared with ciprofloxacin against escherichia coli and compound 53 exhibited excellent antibacterial activity against salmonella typhi. the selected compounds exhibited also potent inhibition against topo ii and topo iv with ic 50 values in the range 9.4-25 mg/l. liu and colleagues made a huge effort to synthesize and identify coumarin-pyrazole carboxamide derivatives as potential topoisomerase-ii inhibitors: 70 novel compounds were obtained and evaluated [87] . three of them (52-54, figure 21 ) were endowed with promising antimicrobial activities. in particular, compound 52 showed a considerable inhibitory activity compared with ciprofloxacin against escherichia coli and compound 53 exhibited excellent antibacterial activity against salmonella typhi. the selected compounds exhibited also potent inhibition against topo ii and topo iv with ic50 values in the range 9.4-25 mg/l. fungal diseases are a well-known plague for animal and plant worlds but a more hidden menace for human health. more than 90% of all reported fungal-related deaths results from species that belong to one of four genera: cryptococcus, candida, aspergillus and pneumocystis [88] [89] [90] . coumarin derivatives are endowed with antifungal activity, potentially useful in both pharma and agri-food sectors. in this fungal diseases are a well-known plague for animal and plant worlds but a more hidden menace for human health. more than 90% of all reported fungal-related deaths results from species that belong to one of four genera: cryptococcus, candida, aspergillus and pneumocystis [88] [89] [90] . coumarin derivatives are endowed with antifungal activity, potentially useful in both pharma and agri-food sectors. in this paragraph, we will focus on the recent progresses in the development of novel antifungal drugs for human use whereas agri-food applications can be found in section 3.2, food systems. diseases by candida species, a family of fungi that normally live on the host epithelial species but can initiate a fatal infection in particular cases like immunodeficiency, are the fourth most common cause of nosocomial blood-stream infections. despite several species of candida can cause disease, candida albicans prevails in term of incidence [88, 91, 92] . therefore, in 2016, shaik and colleagues designed a novel series of coumarin derivatives conjugated with 1,2,3-triazole moieties, on the basis of a previous work by shi and zhou and of the common use of azoles as antifungal drugs [93, 94] . the antifungal potency of the novel compounds was tested against candida albicans and other four fungal pathogens (i.e., fusarium oxysporum, aspergillus flavus, aspergillus niger and cryptococcus neoformans); mic values were evaluated and compared to mic of the reference compounds miconazole and fluconazole. compounds 55-57 and 59 ( figure 22 ) were found to be equipotent to miconazole against c. albicans and compound 58 was found to be two-fold more active compared with miconazole and equipotent to fluconazole. paragraph, we will focus on the recent progresses in the development of novel antifungal drugs for human use whereas agri-food applications can be found in paragraph 3.2, food systems. diseases by candida species, a family of fungi that normally live on the host epithelial species but can initiate a fatal infection in particular cases like immunodeficiency, are the fourth most common cause of nosocomial blood-stream infections. despite several species of candida can cause disease, candida albicans prevails in term of incidence [88, 91, 92] . therefore, in 2016, shaik and colleagues designed a novel series of coumarin derivatives conjugated with 1,2,3-triazole moieties, on the basis of a previous work by shi and zhou and of the common use of azoles as antifungal drugs [93, 94] . the antifungal potency of the novel compounds was tested against candida albicans and other four fungal pathogens (i.e., fusarium oxysporum, aspergillus flavus, aspergillus niger and cryptococcus neoformans); mic values were evaluated and compared to mic of the reference compounds miconazole and fluconazole. compounds 55-57 and 59 ( figure 22 ) were found to be equipotent to miconazole against c. albicans and compound 58 was found to be two-fold more active compared with miconazole and equipotent to fluconazole. furthermore, molecular docking studies showed that these compounds have a high affinity toward the active site of enzyme p450 cytochrome lanosterol 14α-demethylase and analysis of adme parameters confirmed their drug-like properties [94] . in 2017, fifteen novel coumarin derivatives were synthesized by tiwari et al., under solvent free conditions and exploiting the ionic liquid [et3nh][hso4] as a catalyst [95] . the compounds were tested both for their antifungal and antibacterial activities and, among the series, compounds 60 and 61 resulted to be the most potent as fungicides ( figure 23 ). the mic values observed for compound 60 and 61 were comparable to the standard drug miconazole. furthermore, molecular docking studies showed that these compounds have a high affinity toward the active site of enzyme p450 cytochrome lanosterol 14α-demethylase and analysis of adme parameters confirmed their drug-like properties [94] . in 2017, fifteen novel coumarin derivatives were synthesized by tiwari et al., under solvent free conditions and exploiting the ionic liquid [et 3 nh][hso 4 ] as a catalyst [95] . the compounds were tested both for their antifungal and antibacterial activities and, among the series, compounds 60 and 61 resulted to be the most potent as fungicides ( figure 23 ). the mic values observed for compound 60 and 61 were comparable to the standard drug miconazole. paragraph, we will focus on the recent progresses in the development of novel antifungal drugs for human use whereas agri-food applications can be found in paragraph 3.2, food systems. diseases by candida species, a family of fungi that normally live on the host epithelial species but can initiate a fatal infection in particular cases like immunodeficiency, are the fourth most common cause of nosocomial blood-stream infections. despite several species of candida can cause disease, candida albicans prevails in term of incidence [88, 91, 92] . therefore, in 2016, shaik and colleagues designed a novel series of coumarin derivatives conjugated with 1,2,3-triazole moieties, on the basis of a previous work by shi and zhou and of the common use of azoles as antifungal drugs [93, 94] . the antifungal potency of the novel compounds was tested against candida albicans and other four fungal pathogens (i.e., fusarium oxysporum, aspergillus flavus, aspergillus niger and cryptococcus neoformans); mic values were evaluated and compared to mic of the reference compounds miconazole and fluconazole. compounds 55-57 and 59 ( figure 22 ) were found to be equipotent to miconazole against c. albicans and compound 58 was found to be two-fold more active compared with miconazole and equipotent to fluconazole. furthermore, molecular docking studies showed that these compounds have a high affinity toward the active site of enzyme p450 cytochrome lanosterol 14α-demethylase and analysis of adme parameters confirmed their drug-like properties [94] . in 2017, fifteen novel coumarin derivatives were synthesized by tiwari et al., under solvent free conditions and exploiting the ionic liquid [et3nh][hso4] as a catalyst [95] . the compounds were tested both for their antifungal and antibacterial activities and, among the series, compounds 60 and 61 resulted to be the most potent as fungicides ( figure 23 ). the mic values observed for compound 60 and 61 were comparable to the standard drug miconazole. further studies demonstrated that compound 60 acts by inhibiting ergosterol biosynthesis in c. albicans. molecular docking studies revealed, as for previous study on compounds 55-59, a highly spontaneous binding ability of the tested compounds to the active site of lanosterol 14α-demethylase, which suggests that the tested compounds inhibit the synthesis of this enzyme. moreover, in silico admet properties were evaluated and demonstrated that all the compounds exhibited a good percent absorption (% abs) ranging from 84.9% to 100%. moreover, these compounds had proven to be safe after in vitro toxicity, in vivo acute oral toxicity and behavioral studies. coumarin-based antifungal azoles had been further investigated by elias and co-workers, who, in 2019, developed a series of 11 coumarins conjugated with 1,2,4-triazole and imidazole motifs [96] . the analysis of the biological effects of these novel chemical entities highlighted that imidazole-based derivatives ( figure 24 ) were more efficient against several candida strains compared to 1,2,4-triazole derivatives. moreover, the mode of action of the two classes of compounds were different. whereas the antifungal activity of the triazole-based azoles was dependent on expression of cyp51, the target of the azole antifungals, imidazole-based compounds displayed antifungal activity against a mutant lacking cyp51, indicating that imidazole-based azole antifungals have additional modes of action. this peculiarity could be favorable in the struggle against drugs-resistant fungal strains. further studies demonstrated that compound 60 acts by inhibiting ergosterol biosynthesis in c. albicans. molecular docking studies revealed, as for previous study on compounds 55-59, a highly spontaneous binding ability of the tested compounds to the active site of lanosterol 14α-demethylase, which suggests that the tested compounds inhibit the synthesis of this enzyme. moreover, in silico admet properties were evaluated and demonstrated that all the compounds exhibited a good percent absorption (% abs) ranging from 84.9% to 100%. moreover, these compounds had proven to be safe after in vitro toxicity, in vivo acute oral toxicity and behavioral studies. coumarin-based antifungal azoles had been further investigated by elias and co-workers, who, in 2019, developed a series of 11 coumarins conjugated with 1,2,4-triazole and imidazole motifs [96] . the analysis of the biological effects of these novel chemical entities highlighted that imidazole-based derivatives ( figure 24 ) were more efficient against several candida strains compared to 1,2,4-triazole derivatives. moreover, the mode of action of the two classes of compounds were different. whereas the antifungal activity of the triazole-based azoles was dependent on expression of cyp51, the target of the azole antifungals, imidazole-based compounds displayed antifungal activity against a mutant lacking cyp51, indicating that imidazole-based azole antifungals have additional modes of action. this peculiarity could be favorable in the struggle against drugs-resistant fungal strains. furthermore, it should not be forgotten the contribution of natural coumarins to the fight against candida infections. ferulago trachycarpa boiss. is one of the species of ferulago w. koch., common in anatolian region, exploited in traditional medicine but also in culinary field. previous studies showed that coumarins are the main compounds found in ferulago but only in 2018, dikpinar and colleagues conducted the first antimicrobial activity guided isolation of the molecular constituent of this particular species of ferulago [97] . four coumarin compounds ( figure 25 ) were isolated and purified and then three of them were tested against bacterial and fungal strains; in particular, marmesin senesioate, suberosin and crenulatin showed antifungal activity with 625 mg/l mic against candida albicans. the antifungal potency of coumarin itself against candida albicans had been previously evaluated, in particular its antibiofilm activity [98, 99] . recently, xu and co-workers focused their attention on the possible way to prevent the adhesion and formation of biofilm by candida albicans on implanted medical devices. the research group observed that coumarin not only suppresses biofilm formation but also affects the structure of the mature biofilm; moreover the adhesion, the cell surface hydrophobicity (csh) and the filamentous growth of c. albicans significantly decreased after coumarin treatment, indicating that coumarin inhibits biofilm formation by suppressing adhesion [100] . further studies demonstrated that compound 60 acts by inhibiting ergosterol biosynthesis in c. albicans. molecular docking studies revealed, as for previous study on compounds 55-59, a highly spontaneous binding ability of the tested compounds to the active site of lanosterol 14α-demethylase, which suggests that the tested compounds inhibit the synthesis of this enzyme. moreover, in silico admet properties were evaluated and demonstrated that all the compounds exhibited a good percent absorption (% abs) ranging from 84.9% to 100%. moreover, these compounds had proven to be safe after in vitro toxicity, in vivo acute oral toxicity and behavioral studies. coumarin-based antifungal azoles had been further investigated by elias and co-workers, who, in 2019, developed a series of 11 coumarins conjugated with 1,2,4-triazole and imidazole motifs [96] . the analysis of the biological effects of these novel chemical entities highlighted that imidazole-based derivatives ( figure 24 ) were more efficient against several candida strains compared to 1,2,4-triazole derivatives. moreover, the mode of action of the two classes of compounds were different. whereas the antifungal activity of the triazole-based azoles was dependent on expression of cyp51, the target of the azole antifungals, imidazole-based compounds displayed antifungal activity against a mutant lacking cyp51, indicating that imidazole-based azole antifungals have additional modes of action. this peculiarity could be favorable in the struggle against drugs-resistant fungal strains. furthermore, it should not be forgotten the contribution of natural coumarins to the fight against candida infections. ferulago trachycarpa boiss. is one of the species of ferulago w. koch., common in anatolian region, exploited in traditional medicine but also in culinary field. previous studies showed that coumarins are the main compounds found in ferulago but only in 2018, dikpinar and colleagues conducted the first antimicrobial activity guided isolation of the molecular constituent of this particular species of ferulago [97] . four coumarin compounds ( figure 25 ) were isolated and purified and then three of them were tested against bacterial and fungal strains; in particular, marmesin senesioate, suberosin and crenulatin showed antifungal activity with 625 mg/l mic against candida albicans. the antifungal potency of coumarin itself against candida albicans had been previously evaluated, in particular its antibiofilm activity [98, 99] . recently, xu and co-workers focused their attention on the possible way to prevent the adhesion and formation of biofilm by candida albicans on implanted medical devices. the research group observed that coumarin not only suppresses biofilm formation but also affects the structure of the mature biofilm; moreover the adhesion, the cell surface hydrophobicity (csh) and the filamentous growth of c. albicans significantly decreased after coumarin treatment, indicating that coumarin inhibits biofilm formation by suppressing adhesion [100] . the antifungal potency of coumarin itself against candida albicans had been previously evaluated, in particular its antibiofilm activity [98, 99] . recently, xu and co-workers focused their attention on the possible way to prevent the adhesion and formation of biofilm by candida albicans on implanted medical devices. the research group observed that coumarin not only suppresses biofilm formation but also affects the structure of the mature biofilm; moreover the adhesion, the cell surface hydrophobicity (csh) and the filamentous growth of c. albicans significantly decreased after coumarin treatment, indicating that coumarin inhibits biofilm formation by suppressing adhesion [100] . the antifungal potency of coumarin-based triazoles against other fungal strains in addition to candida species had been evaluated by dharavath and colleagues in 2020. coumarin-based 1,4-disubstituted 1,2,3-triazole derivatives were synthesized using a highly efficient, eco-friendly protocol via a copper(i)-catalyzed click reaction between various substituted arylazides and terminal alkynes. the in vitro antifungal activity was tested against aspergillus niger, aspergillus flavus and fusarium oxysporum by using the disc diffusion method and the results were compared with those of clotrimazole, the reference drug. compounds 63-68 ( figure 26 ), characterized by the presence of a para-substituted phenyl moiety, directly linked to the triazole ring, showed comparable activity in respect to the reference compound clotrimazol [101, 102] . the antifungal potency of coumarin-based triazoles against other fungal strains in addition to candida species had been evaluated by dharavath and colleagues in 2020. coumarin-based 1,4disubstituted 1,2,3-triazole derivatives were synthesized using a highly efficient, eco-friendly protocol via a copper(i)-catalyzed click reaction between various substituted arylazides and terminal alkynes. the in vitro antifungal activity was tested against aspergillus niger, aspergillus flavus and fusarium oxysporum by using the disc diffusion method and the results were compared with those of clotrimazole, the reference drug. compounds 63-68 ( figure 26 ), characterized by the presence of a para-substituted phenyl moiety, directly linked to the triazole ring, showed comparable activity in respect to the reference compound clotrimazol [101, 102] . 2020 has been a crucial year for the timeless war between human and viruses: world health organization (who) declared the outbreak of sars-covid-19 a public health emergency of international concern on 30 january 2020 and on 11 march who characterized covid-19 as a pandemic [103] . whole developed countries have been quarantined and generations that never faced medical crisis are now struggling with the consequences of the viral diffusion. human history is afflicted by the cyclic succession of pandemic events and the research of new antivirals is still ongoing, due to the ability of viruses to mutate and the continuous appearance of new viruses on the medical scenario [104] . the natural world is a priceless source of valuable medical compounds and also in the fight against viral diseases there are several natural molecules which exhibit antiviral activity [105] [106] [107] [108] [109] . coumarins, likewise other polyphenolic compounds, exert a remarkable antiviral activity [110, 111] . the antiviral activity of coumarins explicates through different mechanisms which affect the life cycle of viruses and their biological activities could be changed depending upon the combination of various substituents and conjugates [104, 112] . coumarins appears to be active against several viruses, like hiv, influenza, hepatitis, dengue and chikunguya [104] . liu and co-workers after a phytochemical study on the stem of clausena lenis isolated three new and nine known prenylated coumarins [113] . all the prenylated coumarins were evaluated both for their anti-inflammatory and anti-hiv reverse transcriptase (rt) activities. in this last case, the inhibition assay for the cytopathic activities of hiv-1 (ec50) as well as cytotoxic activity assay against c8166 cell line (cc50) according to mtt methods were applied [114, 115] . the three new isolated compounds (69-71, figure 27 ) showed the best inhibitory activity with an ec50 of 0.29, 0.68 and 0.17 μm, respectively. furthermore, no cytotoxicity was observed against c8166 cell line (cc50 > 200.00 μm). 2.6. antiviral activity 2020 has been a crucial year for the timeless war between human and viruses: world health organization (who) declared the outbreak of sars-covid-19 a public health emergency of international concern on 30 january 2020 and on 11 march who characterized covid-19 as a pandemic [103] . whole developed countries have been quarantined and generations that never faced medical crisis are now struggling with the consequences of the viral diffusion. human history is afflicted by the cyclic succession of pandemic events and the research of new antivirals is still ongoing, due to the ability of viruses to mutate and the continuous appearance of new viruses on the medical scenario [104] . the natural world is a priceless source of valuable medical compounds and also in the fight against viral diseases there are several natural molecules which exhibit antiviral activity [105] [106] [107] [108] [109] . coumarins, likewise other polyphenolic compounds, exert a remarkable antiviral activity [110, 111] . the antiviral activity of coumarins explicates through different mechanisms which affect the life cycle of viruses and their biological activities could be changed depending upon the combination of various substituents and conjugates [104, 112] . coumarins appears to be active against several viruses, like hiv, influenza, hepatitis, dengue and chikunguya [104] . liu and co-workers after a phytochemical study on the stem of clausena lenis isolated three new and nine known prenylated coumarins [113] . all the prenylated coumarins were evaluated both for their anti-inflammatory and anti-hiv reverse transcriptase (rt) activities. in this last case, the inhibition assay for the cytopathic activities of hiv-1 (ec 50 ) as well as cytotoxic activity assay against c8166 cell line (cc 50 ) according to mtt methods were applied [114, 115] . the three new isolated compounds (69-71, figure 27 ) showed the best inhibitory activity with an ec 50 prenylated coumarins came to the fore in 2019 thanks to a work by liu et al., who revealed for the first time the presence of these type of derivatives in the fruits of manilkara zapota, an ever-green tropical tree. also in this case, three new derivatives were identified (72-74, figure 28 ) together with seven known compounds and the team evaluated their anti-inflammatory and anti-hiv activities, exploiting the methods described above [116] . prenylated coumarins came to the fore in 2019 thanks to a work by liu et al., who revealed for the first time the presence of these type of derivatives in the fruits of manilkara zapota, an ever-green tropical tree. also in this case, three new derivatives were identified (72-74, figure 28 ) together with seven known compounds and the team evaluated their anti-inflammatory and anti-hiv activities, exploiting the methods described above [116] . prenylated coumarins came to the fore in 2019 thanks to a work by liu et al., who revealed for the first time the presence of these type of derivatives in the fruits of manilkara zapota, an ever-green tropical tree. also in this case, three new derivatives were identified (72-74, figure 28 ) together with seven known compounds and the team evaluated their anti-inflammatory and anti-hiv activities, exploiting the methods described above [116] . the new prenylated coumarins showed the highest anti-hiv rt effect among the prenylated coumarins derived from the fruit of manilkara zapota; in particular, compound 72 displayed the most powerful effect with an ec50 value of 0.12 μm. comparative studies between compounds 72-74 and the other coumarin derivatives isolated from the fruits highlighted the importance of the isopentenyl group as a substituent at c6 and 2-methylbut-3-en-2-yl group as a substituent at c3 for the anti-hiv rt effect. in the same year, jesumoroti and co-workers approached the problem from another point of view, both regarding the target and the origin of the coumarin derivatives [117] . first of all, a different viral target was chosen, hiv-1 in, which is essential for a stable infection. moreover, there are no homologous enzymes in the host cell [118] . secondarily, the coumarin derivatives were obtained decorating the coumarin nucleus with an hydrazide group, in order to achieve a synergistic effect against-hiv-1-in and reducing the toxicity correlated to the salicylhydrazide, which was however essential for the activity [119] [120] [121] . the synthesized compounds were evaluated for their in vitro hiv-1 in inhibitory activity using chicoric acid (ca) as a reference compound, according to the method described by mccoll et al. [122] . compounds 75-78 ( figure 29 ) appeared to be the most active among the whole series showing an inhibition of extracellular in (evaluated in vitro according to the method described by mccoll et al. [122] ) in a range from 95% to 86 % and ic50 between 13 nm (compound 76) and 31 nm (ca ic50=10 nm). furthermore, the cytotoxicity of all the obtained compounds was tested and derivatives 75-78 showed low or negligible cytotoxicity. the new prenylated coumarins showed the highest anti-hiv rt effect among the prenylated coumarins derived from the fruit of manilkara zapota; in particular, compound 72 displayed the most powerful effect with an ec 50 value of 0.12 µm. comparative studies between compounds 72-74 and the other coumarin derivatives isolated from the fruits highlighted the importance of the isopentenyl group as a substituent at c6 and 2-methylbut-3-en-2-yl group as a substituent at c3 for the anti-hiv rt effect. in the same year, jesumoroti and co-workers approached the problem from another point of view, both regarding the target and the origin of the coumarin derivatives [117] . first of all, a different viral target was chosen, hiv-1 in, which is essential for a stable infection. moreover, there are no homologous enzymes in the host cell [118] . secondarily, the coumarin derivatives were obtained decorating the coumarin nucleus with an hydrazide group, in order to achieve a synergistic effect against-hiv-1-in and reducing the toxicity correlated to the salicylhydrazide, which was however essential for the activity [119] [120] [121] . the synthesized compounds were evaluated for their in vitro hiv-1 in inhibitory activity using chicoric acid (ca) as a reference compound, according to the method described by mccoll et al. [122] . compounds 75-78 ( figure 29 ) appeared to be the most active among the whole series showing an inhibition of extracellular in (evaluated in vitro according to the method described by mccoll et al. [122] ) in a range from 95% to 86 % and ic 50 between 13 nm (compound 76) and 31 nm (ca ic 50 = 10 nm). furthermore, the cytotoxicity of all the obtained compounds was tested and derivatives 75-78 showed low or negligible cytotoxicity. prenylated coumarins came to the fore in 2019 thanks to a work by liu et al., who revealed for the first time the presence of these type of derivatives in the fruits of manilkara zapota, an ever-green tropical tree. also in this case, three new derivatives were identified (72-74, figure 28 ) together with seven known compounds and the team evaluated their anti-inflammatory and anti-hiv activities, exploiting the methods described above [116] . the new prenylated coumarins showed the highest anti-hiv rt effect among the prenylated coumarins derived from the fruit of manilkara zapota; in particular, compound 72 displayed the most powerful effect with an ec50 value of 0.12 μm. comparative studies between compounds 72-74 and the other coumarin derivatives isolated from the fruits highlighted the importance of the isopentenyl group as a substituent at c6 and 2-methylbut-3-en-2-yl group as a substituent at c3 for the anti-hiv rt effect. in the same year, jesumoroti and co-workers approached the problem from another point of view, both regarding the target and the origin of the coumarin derivatives [117] . first of all, a different viral target was chosen, hiv-1 in, which is essential for a stable infection. moreover, there are no homologous enzymes in the host cell [118] . secondarily, the coumarin derivatives were obtained decorating the coumarin nucleus with an hydrazide group, in order to achieve a synergistic effect against-hiv-1-in and reducing the toxicity correlated to the salicylhydrazide, which was however essential for the activity [119] [120] [121] . the synthesized compounds were evaluated for their in vitro hiv-1 in inhibitory activity using chicoric acid (ca) as a reference compound, according to the method described by mccoll et al. [122] . compounds 75-78 ( figure 29 ) appeared to be the most active among the whole series showing an inhibition of extracellular in (evaluated in vitro according to the method described by mccoll et al. [122] ) in a range from 95% to 86 % and ic50 between 13 nm (compound 76) and 31 nm (ca ic50=10 nm). furthermore, the cytotoxicity of all the obtained compounds was tested and derivatives 75-78 showed low or negligible cytotoxicity. seasonal influenza claims around 0.29-0.65 million victims annually, even if several drugs are commercially available [123] . the flu is a contagious respiratory disease caused by influenza viruses, manifesting major epidemics with no predictable periodicity or pattern and all different from one to another [124] . for these reasons, a constant effort in the development of new drugs for the treatment of this disease is of greatest importance. in 2019 osman and co-workers combined two bioactive moieties into a single molecule in order to obtain new bioactive compounds with antibacterial and antiviral effects [125] . in particular, based on a previous study of the same research team, in which coumarin scaffolds and thiazole moiety were combined leading to compounds endowed with both antibacterial and antiviral activities, the potentiality of this combination was further explored [126] , [127] . four new molecules of the series showed a remarkable antiviral activity against h1n1 virus. compounds 79-82 ( figure 30 ) seemed to be promising agents, having ic 50 values of 4.84, 19.72, 6.12 and 9.13 µg/ml, respectively, against the h1n1 virus. commercially available [123] . the flu is a contagious respiratory disease caused by influenza viruses, manifesting major epidemics with no predictable periodicity or pattern and all different from one to another [124] . for these reasons, a constant effort in the development of new drugs for the treatment of this disease is of greatest importance. in 2019 osman and co-workers combined two bioactive moieties into a single molecule in order to obtain new bioactive compounds with antibacterial and antiviral effects [125] . in particular, based on a previous study of the same research team, in which coumarin scaffolds and thiazole moiety were combined leading to compounds endowed with both antibacterial and antiviral activities, the potentiality of this combination was further explored [126] , [127] . four new molecules of the series showed a remarkable antiviral activity against h1n1 virus. compounds 79-82 ( figure 30 ) seemed to be promising agents, having ic50 values of 4.84, 19.72, 6.12 and 9.13 μg/ml, respectively, against the h1n1 virus. bizzarri et al. exploited the regioselective oxidation of coumarin derivatives with 2iodoxybenzoic acid (ibx) in order to obtain catechol and pyrogallol moieties [129] . after cytotoxicity studies that confirmed the safety of the series of derivatives, the antiviral activity against influenza viruses a/pr8/h1n1 was evaluated and compounds 84-89 ( figure 32 ) resulted able to inhibit the viral replication. interestingly, pyrogallol derivatives 88 (ic50 = 69.9 μg/ml) and 89 (ic50 = 47.9 μg/ml) turned out to be more active than catechol derivatives 84 (ic50 = 106.5 μg/ml) and 85 (ic50 = 91.5 μg/ml). moreover, pyrogallol and catechol derivatives were more active than the monohydroxycoumarins 6-hydroxycoumarin and 7-hydroxycoumarin (ic50 110 μg/ml for both the parent compounds). commercially available [123] . the flu is a contagious respiratory disease caused by influenza viruses, manifesting major epidemics with no predictable periodicity or pattern and all different from one to another [124] . for these reasons, a constant effort in the development of new drugs for the treatment of this disease is of greatest importance. in 2019 osman and co-workers combined two bioactive moieties into a single molecule in order to obtain new bioactive compounds with antibacterial and antiviral effects [125] . in particular, based on a previous study of the same research team, in which coumarin scaffolds and thiazole moiety were combined leading to compounds endowed with both antibacterial and antiviral activities, the potentiality of this combination was further explored [126] , [127] . four new molecules of the series showed a remarkable antiviral activity against h1n1 virus. compounds 79-82 ( figure 30 ) seemed to be promising agents, having ic50 values of 4.84, 19.72, 6.12 and 9.13 μg/ml, respectively, against the h1n1 virus. bizzarri et al. exploited the regioselective oxidation of coumarin derivatives with 2iodoxybenzoic acid (ibx) in order to obtain catechol and pyrogallol moieties [129] . after cytotoxicity studies that confirmed the safety of the series of derivatives, the antiviral activity against influenza viruses a/pr8/h1n1 was evaluated and compounds 84-89 ( figure 32 ) resulted able to inhibit the viral replication. interestingly, pyrogallol derivatives 88 (ic50 = 69.9 μg/ml) and 89 (ic50 = 47.9 μg/ml) turned out to be more active than catechol derivatives 84 (ic50 = 106.5 μg/ml) and 85 (ic50 = 91.5 μg/ml). moreover, pyrogallol and catechol derivatives were more active than the monohydroxycoumarins 6-hydroxycoumarin and 7-hydroxycoumarin (ic50 110 μg/ml for both the parent compounds). bizzarri et al. exploited the regioselective oxidation of coumarin derivatives with 2-iodoxybenzoic acid (ibx) in order to obtain catechol and pyrogallol moieties [129] . after cytotoxicity studies that confirmed the safety of the series of derivatives, the antiviral activity against influenza viruses a/pr8/h1n1 was evaluated and compounds 84-89 ( figure 32 ) resulted able to inhibit the viral replication. interestingly, pyrogallol derivatives 88 (ic 50 = 69.9 µg/ml) and 89 (ic 50 = 47.9 µg/ml) turned out to be more active than catechol derivatives 84 (ic 50 = 106.5 µg/ml) and 85 (ic 50 = 91.5 µg/ml). moreover, pyrogallol and catechol derivatives were more active than the monohydroxycoumarins 6-hydroxycoumarin and 7-hydroxycoumarin (ic 50 110 µg/ml for both the parent compounds). one of the possible advantages of oxidized coumarins could be their mode of action against viruses. indeed, due to their antioxidant activity, coumarins derivatives could affect intracellular redox-sensitive pathways useful for viral replication, independently from the variability of the strains [129] . as already mentioned, coumarins have been studied also for their potential application as antihepatitis agents. tsay and co-workers studied the activity against hepatitis c virus (hcv) of some unnatural imidazole-coumarin conjugates [130] . above all, three compounds (90-92, figure 33 ) showed a noteworthy antiviral activity against hcv with ec50 values ranging from 5.1 to 8.4 μm and selective indices (si = cc50/ec50, which is a measure for the therapeutic window of the compound in an assay system) higher than 20. huang and co-workers focused their attention on the investigation of the potentiality expressed by esculetin (or 6,7-dihydroxycoumarin) against hepatitis b virus (hbv) [131] . the results suggested that esculetin efficiently inhibits hbv replication both in vitro and in vivo, which provides an opportunity for further development of the compound as antiviral agent. inflammation is a general physiological response that aims, firstly, to the circumscription of the harmful factors, which could be both endogenous (e.g., cancer, ischemia, autoimmune diseases) and exogenous (e.g., viral or bacterial infections, trauma), secondarily, to the removal of the causes of the damage and finally to the reparation of the tissues and restoration of the functions. nevertheless, the inflammation and the consequent restorative process could become harmful for the organism itself when there is a persistent stimulation and the phases of inflammation and reconstruction are contemporary activated, causing tissue injuries and fibrosis [132] . during an inflammatory process, many inflammatory effectors and mediators are produced and involved, often with a common effect on vascular system and on the recruitment of leukocytes [133] . frequently, inflammatory mediators are the target of anti-inflammatory drugs [134] [135] [136] [137] . one of the possible advantages of oxidized coumarins could be their mode of action against viruses. indeed, due to their antioxidant activity, coumarins derivatives could affect intracellular redox-sensitive pathways useful for viral replication, independently from the variability of the strains [129] . as already mentioned, coumarins have been studied also for their potential application as anti-hepatitis agents. tsay and co-workers studied the activity against hepatitis c virus (hcv) of some unnatural imidazole-coumarin conjugates [130] . above all, three compounds (90-92, figure 33 ) showed a noteworthy antiviral activity against hcv with ec 50 values ranging from 5.1 to 8.4 µm and selective indices (si = cc 50 /ec 50 , which is a measure for the therapeutic window of the compound in an assay system) higher than 20. one of the possible advantages of oxidized coumarins could be their mode of action against viruses. indeed, due to their antioxidant activity, coumarins derivatives could affect intracellular redox-sensitive pathways useful for viral replication, independently from the variability of the strains [129] . as already mentioned, coumarins have been studied also for their potential application as antihepatitis agents. tsay and co-workers studied the activity against hepatitis c virus (hcv) of some unnatural imidazole-coumarin conjugates [130] . above all, three compounds (90-92, figure 33 ) showed a noteworthy antiviral activity against hcv with ec50 values ranging from 5.1 to 8.4 μm and selective indices (si = cc50/ec50, which is a measure for the therapeutic window of the compound in an assay system) higher than 20. huang and co-workers focused their attention on the investigation of the potentiality expressed by esculetin (or 6,7-dihydroxycoumarin) against hepatitis b virus (hbv) [131] . the results suggested that esculetin efficiently inhibits hbv replication both in vitro and in vivo, which provides an opportunity for further development of the compound as antiviral agent. inflammation is a general physiological response that aims, firstly, to the circumscription of the harmful factors, which could be both endogenous (e.g., cancer, ischemia, autoimmune diseases) and exogenous (e.g., viral or bacterial infections, trauma), secondarily, to the removal of the causes of the damage and finally to the reparation of the tissues and restoration of the functions. nevertheless, the inflammation and the consequent restorative process could become harmful for the organism itself when there is a persistent stimulation and the phases of inflammation and reconstruction are contemporary activated, causing tissue injuries and fibrosis [132] . during an inflammatory process, many inflammatory effectors and mediators are produced and involved, often with a common effect on vascular system and on the recruitment of leukocytes [133] . frequently, inflammatory mediators are the target of anti-inflammatory drugs [134] [135] [136] [137] . huang and co-workers focused their attention on the investigation of the potentiality expressed by esculetin (or 6,7-dihydroxycoumarin) against hepatitis b virus (hbv) [131] . the results suggested that esculetin efficiently inhibits hbv replication both in vitro and in vivo, which provides an opportunity for further development of the compound as antiviral agent. inflammation is a general physiological response that aims, firstly, to the circumscription of the harmful factors, which could be both endogenous (e.g., cancer, ischemia, autoimmune diseases) and exogenous (e.g., viral or bacterial infections, trauma), secondarily, to the removal of the causes of the damage and finally to the reparation of the tissues and restoration of the functions. nevertheless, the inflammation and the consequent restorative process could become harmful for the organism itself when there is a persistent stimulation and the phases of inflammation and reconstruction are contemporary activated, causing tissue injuries and fibrosis [132] . during an inflammatory process, many inflammatory effectors and mediators are produced and involved, often with a common effect on vascular system and on the recruitment of leukocytes [133] . frequently, inflammatory mediators are the target of anti-inflammatory drugs [134] [135] [136] [137] . among the numerous biological activities shown by coumarin derivatives, the anti-inflammatory effect could not certainly miss. dawood et al., in 2015 , developed a new series of coumarin derivatives hybridizing two pharmacophoric moieties-the coumarin scaffold itself and thiazoline or thiazolidinone groups, both showing cyclooxygenase 2 (cox-2) inhibitor effect [127] , [138] [139] [140] [141] [142] [143] . the compounds were evaluated in vivo for their systemic effect, in vitro for their ability to inhibit human cox-1 and cox-2 and also to evaluate the ulcerogenic potential compared to the reference drug, indomethacin, always following standard methods reported in literature. most of the new compounds showed significant in vivo anti-inflammatory activity with a superior gastro-intestinal safety profiles (0-7% ulceration) as compared to indomethacin. the ic 50 among the numerous biological activities shown by coumarin derivatives, the antiinflammatory effect could not certainly miss. dawood et al., in 2015 , developed a new series of coumarin derivatives hybridizing two pharmacophoric moieties-the coumarin scaffold itself and thiazoline or thiazolidinone groups, both showing cyclooxygenase 2 (cox-2) inhibitor effect [127] , [138] [139] [140] [141] [142] [143] . the compounds were evaluated in vivo for their systemic effect, in vitro for their ability to inhibit human cox-1 and cox-2 and also to evaluate the ulcerogenic potential compared to the reference drug, indomethacin, always following standard methods reported in literature. most of the new compounds showed significant in vivo anti-inflammatory activity with a superior gastrointestinal safety profiles (0-7% ulceration) as compared to indomethacin. the ic50 values of all the bioactive compounds ranged between 0.31 and 0.78 mm, showing an in vitro high affinity and selectivity toward the cox-2 isoenzyme, compared to the reference celecoxib. ethyl thiosemicarbazone 93, thiazoline derivatives 94-98 and the thiazolidinone compounds 99-100 exhibited the highest in vivo and in vitro anti-inflammatory activities with good cox-2 selectivity ( figure 34 ) [143] . nevertheless, cyclooxygenases are not the only enzymes involved in the inflammatory process. actually, 5-lipoxygenase (5-lox) catalyzes two different steps in the arachidonic acid metabolism that brings to the production of leukotriene a4, which is successively metabolized into leukotriene b4 [144] . molecular inhibitors of leukotrienes competitively bind the active site of 5-lox and are divided in three category: redox-active compounds (i.e., coumarins), iron-ligand inhibitors with weak redoxactive properties and non-redox-type inhibitors [145] . in 2016, srivastava and colleagues evaluated the anti-inflammatory and analgesic effect of a series of synthesized 7-substituted coumarins and, consequently, the most active compounds were assessed in vitro for 5-lox inhibition [146] . compounds 101 and 102 ( figure 35 ) resulted the most promising derivatives, also in the ulcerogenic risk evaluation when compared to acetylsalicylic acid. in vitro kinetic study of compound 102 (ic50 = 2.09 nm) showed mixed or non-competitive type of inhibition of 5-lox. the presence of a substituent on c6 position of benzothiazole ring was found very important for increasing the activity. nevertheless, cyclooxygenases are not the only enzymes involved in the inflammatory process. actually, 5-lipoxygenase (5-lox) catalyzes two different steps in the arachidonic acid metabolism that brings to the production of leukotriene a 4 , which is successively metabolized into leukotriene b 4 [144] . molecular inhibitors of leukotrienes competitively bind the active site of 5-lox and are divided in three category: redox-active compounds (i.e., coumarins), iron-ligand inhibitors with weak redox-active properties and non-redox-type inhibitors [145] . in 2016, srivastava and colleagues evaluated the anti-inflammatory and analgesic effect of a series of synthesized 7-substituted coumarins and, consequently, the most active compounds were assessed in vitro for 5-lox inhibition [146] . compounds 101 and 102 ( figure 35 ) resulted the most promising derivatives, also in the ulcerogenic risk evaluation when compared to acetylsalicylic acid. in vitro kinetic study of compound 102 (ic 50 = 2.09 nm) showed mixed or non-competitive type of inhibition of 5-lox. the presence of a substituent on c6 position of benzothiazole ring was found very important for increasing the activity. in 2018, liu et al. identified ten new coumarin derivatives (3 monomers and 7 dimers) isolated in a phytochemical study on murraya exotica, a dwarf tree that is native of the tropical and subtropical areas of asia and traditionally used in the treatment of inflammatory-related diseases [147] . previous studies had shown that the main active components in m. exotica were coumarins; also bis-coumarins were isolated from the plant. a further investigation on the 95% aqueous etoh extract of the roots allowed the obtainment of new coumarins, together with other bioactive molecules. the compounds were tested for their inhibitory effect on no production and compound 103 ( figure 36 ) stood out among the coumarins in the inhibition against lps-induced no production in bv-2 microglial cells with ic50 value of 8.6 μm. the nuclear factor-kb (nf-kb) family of transcription factors is composed by a set of related, evolutionarily conserved dna-binding proteins. in response to multiple stimuli such as inflammatory cytokines, bacterial lipopolysaccharide (lps), viral infection or stress, a series of cascade reactions bring towards the entry on nf-kb into the nucleus and to the activation of several genes participating in immune and inflammatory responses, cell adhesion, growth control and regulation of apoptosis [148, 149] . in 2019, fan and co-workers evaluated in vivo and in vitro the antiinflammatory activity of osthole ( figure 37 ) [150] , a natural prenylated coumarin from cnidium monnieri (l.) cuss. but also found in other medicinal plants, which has already shown different biological and pharmacological properties such as neuroprotective, osteogenic, immunomodulatory, anticancer, hepatoprotective, cardiovascular protective and antimicrobial activities [13] . the team established that osthole inhibited the production of no, pge2, tnf-a and il-6 in lps-induced macrophages and suppressed the activity of inos and cox-2, probably by blocking the activation of nf-kb and p38/mapk signaling pathways. in 2018, liu et al. identified ten new coumarin derivatives (3 monomers and 7 dimers) isolated in a phytochemical study on murraya exotica, a dwarf tree that is native of the tropical and subtropical areas of asia and traditionally used in the treatment of inflammatory-related diseases [147] . previous studies had shown that the main active components in m. exotica were coumarins; also bis-coumarins were isolated from the plant. a further investigation on the 95% aqueous etoh extract of the roots allowed the obtainment of new coumarins, together with other bioactive molecules. the compounds were tested for their inhibitory effect on no production and compound 103 ( figure 36 ) stood out among the coumarins in the inhibition against lps-induced no production in bv-2 microglial cells with ic 50 value of 8.6 µm. in 2018, liu et al. identified ten new coumarin derivatives (3 monomers and 7 dimers) isolated in a phytochemical study on murraya exotica, a dwarf tree that is native of the tropical and subtropical areas of asia and traditionally used in the treatment of inflammatory-related diseases [147] . previous studies had shown that the main active components in m. exotica were coumarins; also bis-coumarins were isolated from the plant. a further investigation on the 95% aqueous etoh extract of the roots allowed the obtainment of new coumarins, together with other bioactive molecules. the compounds were tested for their inhibitory effect on no production and compound 103 ( figure 36 ) stood out among the coumarins in the inhibition against lps-induced no production in bv-2 microglial cells with ic50 value of 8.6 μm. the nuclear factor-kb (nf-kb) family of transcription factors is composed by a set of related, evolutionarily conserved dna-binding proteins. in response to multiple stimuli such as inflammatory cytokines, bacterial lipopolysaccharide (lps), viral infection or stress, a series of cascade reactions bring towards the entry on nf-kb into the nucleus and to the activation of several genes participating in immune and inflammatory responses, cell adhesion, growth control and regulation of apoptosis [148, 149] . in 2019, fan and co-workers evaluated in vivo and in vitro the antiinflammatory activity of osthole ( figure 37 ) [150] , a natural prenylated coumarin from cnidium monnieri (l.) cuss. but also found in other medicinal plants, which has already shown different biological and pharmacological properties such as neuroprotective, osteogenic, immunomodulatory, anticancer, hepatoprotective, cardiovascular protective and antimicrobial activities [13] . the team established that osthole inhibited the production of no, pge2, tnf-a and il-6 in lps-induced macrophages and suppressed the activity of inos and cox-2, probably by blocking the activation of nf-kb and p38/mapk signaling pathways. the nuclear factor-kb (nf-kb) family of transcription factors is composed by a set of related, evolutionarily conserved dna-binding proteins. in response to multiple stimuli such as inflammatory cytokines, bacterial lipopolysaccharide (lps), viral infection or stress, a series of cascade reactions bring towards the entry on nf-kb into the nucleus and to the activation of several genes participating in immune and inflammatory responses, cell adhesion, growth control and regulation of apoptosis [148, 149] . in 2019, fan and co-workers evaluated in vivo and in vitro the anti-inflammatory activity of osthole ( figure 37 ) [150] , a natural prenylated coumarin from cnidium monnieri (l.) cuss. but also found in other medicinal plants, which has already shown different biological and pharmacological properties such as neuroprotective, osteogenic, immunomodulatory, anticancer, hepatoprotective, cardiovascular protective and antimicrobial activities [13] . the team established that osthole inhibited the production of no, pge2, tnf-a and il-6 in lps-induced macrophages and suppressed the activity of inos and cox-2, probably by blocking the activation of nf-kb and p38/mapk signaling pathways. in the same year, mu and colleagues synthesized a series of eleven 7-substituted coumarins and evaluated their anti-inflammatory activities and their ability to exploit the nf-kb pathway [151] . all the screened compounds showed a relevant anti-inflammatory activity. in the series, compound 104 ( figure 38 ) was identified as a hit and further studies of molecular docking were conducted confirming that 104 could bind to the active site (nls polypeptide) of nf-κb p65. its binding affinity was further confirmed by surface plasmon resonance (spr) analysis. moreover, western blot assay showed that 104 remarkably blocked the nf-κb signaling pathway in vitro. alzheimer's disease (ad) is the most common form of dementia (60-70% of cases of dementia are cause by ad) and consists in a neurodegenerative disorder characterized by a slow, progressive and irreversible loss of cognitive function and memory [152] [153] [154] [155] [156] [157] . the current therapeutic approach, mainly based on the use of acetylcholinesterase (ache) inhibitors (rivastigmine, donepezil, galantamine) or n-methy-d-aspartic acid (nmda) receptor inhibitors (memantine), is merely symptomatic and does not counteract degeneration progression. new innovative approaches, such as multi-targeted strategies, are urgently required in order to cure cognition and motor dysfunctions, neurodegeneration and depression. among their biological activities, coumarins showed the ability to inhibit some biological targets involved in ad. with this in mind, some recent works aimed at investigating coumarins potential in the treatment of ad are discussed below. in 2019, karakaya and collaborators investigated the antioxidant and ache/buche inhibitory activity of aerial parts, fruits, flowers and root extracts from ferulago cassia boiss [158] . root's and fruit's dichloromethane extracts showed the highest antioxidant potential in tba assay. the evaluation of anticholinesterase activity was carried out by means of the ellman's method [159] : dichloromethane extracts showed significant inhibition against buche (96.56% ± 2.98 and 82.33% ± 2.69, respectively) at 20 μg/ml and appreciable inhibition against ache (53.24 ± 1.22 and 31.38 ± 5.41%, respectively) at 20 μg/ml. four coumarins were isolated from ferulago cassia-peucedanol, suberosin, grandivitinol and umbelliferone ( figure 39 ). therefore, f. cassia can be considered a starting point for the development of new compounds with antioxidant and anticholinesterase activity. in the same year, mu and colleagues synthesized a series of eleven 7-substituted coumarins and evaluated their anti-inflammatory activities and their ability to exploit the nf-kb pathway [151] . all the screened compounds showed a relevant anti-inflammatory activity. in the series, compound 104 ( figure 38 ) was identified as a hit and further studies of molecular docking were conducted confirming that 104 could bind to the active site (nls polypeptide) of nf-κb p65. its binding affinity was further confirmed by surface plasmon resonance (spr) analysis. moreover, western blot assay showed that 104 remarkably blocked the nf-κb signaling pathway in vitro. in the same year, mu and colleagues synthesized a series of eleven 7-substituted coumarins and evaluated their anti-inflammatory activities and their ability to exploit the nf-kb pathway [151] . all the screened compounds showed a relevant anti-inflammatory activity. in the series, compound 104 ( figure 38 ) was identified as a hit and further studies of molecular docking were conducted confirming that 104 could bind to the active site (nls polypeptide) of nf-κb p65. its binding affinity was further confirmed by surface plasmon resonance (spr) analysis. moreover, western blot assay showed that 104 remarkably blocked the nf-κb signaling pathway in vitro. alzheimer's disease (ad) is the most common form of dementia (60-70% of cases of dementia are cause by ad) and consists in a neurodegenerative disorder characterized by a slow, progressive and irreversible loss of cognitive function and memory [152] [153] [154] [155] [156] [157] . the current therapeutic approach, mainly based on the use of acetylcholinesterase (ache) inhibitors (rivastigmine, donepezil, galantamine) or n-methy-d-aspartic acid (nmda) receptor inhibitors (memantine), is merely symptomatic and does not counteract degeneration progression. new innovative approaches, such as multi-targeted strategies, are urgently required in order to cure cognition and motor dysfunctions, neurodegeneration and depression. among their biological activities, coumarins showed the ability to inhibit some biological targets involved in ad. with this in mind, some recent works aimed at investigating coumarins potential in the treatment of ad are discussed below. in 2019, karakaya and collaborators investigated the antioxidant and ache/buche inhibitory activity of aerial parts, fruits, flowers and root extracts from ferulago cassia boiss [158] . root's and fruit's dichloromethane extracts showed the highest antioxidant potential in tba assay. the evaluation of anticholinesterase activity was carried out by means of the ellman's method [159] : dichloromethane extracts showed significant inhibition against buche (96.56% ± 2.98 and 82.33% ± 2.69, respectively) at 20 μg/ml and appreciable inhibition against ache (53.24 ± 1.22 and 31.38 ± 5.41%, respectively) at 20 μg/ml. four coumarins were isolated from ferulago cassia-peucedanol, suberosin, grandivitinol and umbelliferone ( figure 39 ). therefore, f. cassia can be considered a starting point for the development of new compounds with antioxidant and anticholinesterase activity. alzheimer's disease (ad) is the most common form of dementia (60-70% of cases of dementia are cause by ad) and consists in a neurodegenerative disorder characterized by a slow, progressive and irreversible loss of cognitive function and memory [152] [153] [154] [155] [156] [157] . the current therapeutic approach, mainly based on the use of acetylcholinesterase (ache) inhibitors (rivastigmine, donepezil, galantamine) or n-methy-d-aspartic acid (nmda) receptor inhibitors (memantine), is merely symptomatic and does not counteract degeneration progression. new innovative approaches, such as multi-targeted strategies, are urgently required in order to cure cognition and motor dysfunctions, neurodegeneration and depression. among their biological activities, coumarins showed the ability to inhibit some biological targets involved in ad. with this in mind, some recent works aimed at investigating coumarins potential in the treatment of ad are discussed below. in 2019, karakaya and collaborators investigated the antioxidant and ache/buche inhibitory activity of aerial parts, fruits, flowers and root extracts from ferulago cassia boiss [158] . root's and fruit's dichloromethane extracts showed the highest antioxidant potential in tba assay. the evaluation of anticholinesterase activity was carried out by means of the ellman's method [159] : dichloromethane extracts showed significant inhibition against buche (96.56% ± 2.98 and 82.33% ± 2.69, respectively) at 20 µg/ml and appreciable inhibition against ache (53.24 ± 1.22 and 31.38 ± 5.41%, respectively) at 20 µg/ml. four coumarins were isolated from ferulago cassia-peucedanol, suberosin, grandivitinol and umbelliferone ( figure 39 ). therefore, f. cassia can be considered a starting point for the development of new compounds with antioxidant and anticholinesterase activity. thanks to their simple structural architecture and chemical stability, coumarins can be easily synthesized and modified in order to produce more active and selective compounds. najafi and coworkers synthesized a series of tacrine-coumarin derivatives linked to a 1,2,3-triazole moiety and evaluated their activity in terms of ache and butyrylcholinesterase (buche) inhibition, keeping donepezil and tacrine as reference drugs [160] . in addition, their beta-secretase 1 (bace1) inhibitory activity and neuroprotective potential were evaluated. since tacrine is a well-known inhibitor of the catalytic site of ache, whereas coumarins showed affinity for the peripheral anionic site (pas) [161] , this new compounds may be potential dual-and therefore more powerful -inhibitors of ches. the in vitro ache and buche inhibitory activity was evaluated using the ellman's method [159] ; among all the tested molecules, compound 105 resulted the best in ache inhibition (ic5 0= 0.027 ± 0.009 μm; tacrine ic50 = 0.048 ± 0.011 μm, donepezil ic50 = 0.039 ± 0.097 μm) and compound 106 was the most promising buche inhibitor (ic50 = 0.006 ± 0.002 μm; tacrine ic50 = 0.010 ± 0.004 μm, donepezil ic50 = 8.416 ± 0.628 μm) ( figure 40 ). thanks to their simple structural architecture and chemical stability, coumarins can be easily synthesized and modified in order to produce more active and selective compounds. najafi and co-workers synthesized a series of tacrine-coumarin derivatives linked to a 1,2,3-triazole moiety and evaluated their activity in terms of ache and butyrylcholinesterase (buche) inhibition, keeping donepezil and tacrine as reference drugs [160] . in addition, their beta-secretase 1 (bace1) inhibitory activity and neuroprotective potential were evaluated. since tacrine is a well-known inhibitor of the catalytic site of ache, whereas coumarins showed affinity for the peripheral anionic site (pas) [161] , this new compounds may be potential dual-and therefore more powerful -inhibitors of ches. the in vitro ache and buche inhibitory activity was evaluated using the ellman's method [159] ; among all the tested molecules, compound 105 resulted the best in ache inhibition (ic 50 thanks to their simple structural architecture and chemical stability, coumarins can be easily synthesized and modified in order to produce more active and selective compounds. najafi and coworkers synthesized a series of tacrine-coumarin derivatives linked to a 1,2,3-triazole moiety and evaluated their activity in terms of ache and butyrylcholinesterase (buche) inhibition, keeping donepezil and tacrine as reference drugs [160] . in addition, their beta-secretase 1 (bace1) inhibitory activity and neuroprotective potential were evaluated. since tacrine is a well-known inhibitor of the catalytic site of ache, whereas coumarins showed affinity for the peripheral anionic site (pas) [161] , this new compounds may be potential dual-and therefore more powerful -inhibitors of ches. the in vitro ache and buche inhibitory activity was evaluated using the ellman's method [159] ; among all the tested molecules, compound 105 resulted the best in ache inhibition (ic5 0= 0.027 ± 0.009 μm; tacrine ic50 = 0.048 ± 0.011 μm, donepezil ic50 = 0.039 ± 0.097 μm) and compound 106 was the most promising buche inhibitor (ic50 = 0.006 ± 0.002 μm; tacrine ic50 = 0.010 ± 0.004 μm, donepezil ic50 = 8.416 ± 0.628 μm) ( figure 40 ). concerning the anti-buche activity, structure-activity relationship studies showed that cl and me substituents, as well as the methylene linker, play a complex and not completely understood role in the enzyme inhibition. from the evaluation of inhibitory activity of the synthesized compounds on bace1, a moderate inhibitory activity of compound 105 was observed (inhibition of 28.69% and 13.97% at 50 and 10 µm, respectively). nevertheless, compound 105 did not show neuroprotective action on pc12 cells exposed to aβ [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] . then, in vivo evaluation of compound 105 using the morrison water maze method [162] was made and valuable results based on memory improvement in scopolamine-induced impairment were observed. similarly, rastegari and collaborators synthesized a series of 1,2,3-triazole-chromenone carboxamide derivatives and investigated their potential as anti-alzheimer's agents, in terms of inhibitory activity against ache, buche and bace1, besides their neuroprotective and metal-chelating properties [163] . the anti-ache activity of coumarin-3-carboxamide was already known [164] , as well as the ability of the 1,2,3-triazole moiety to enhance achei activity, if linked with tacrine or phenanthridinium derivatives and its bace1 inhibitory potential [165] . in vitro achei and buchei activities of the new compounds were evaluated, keeping donepezil as reference. higher activities were shown by compound 107, bearing 3,4-dimethylbenzyl connected to 1,2,3-triazole moiety and by compound 108, having 3-morpholinopropyl and 2-bromobenzyl moieties ( figure 41 ), even if they are much less active than donepezil (ic 50 = 0.027 µm). anti-bche activity was also modest and resulted to be affected by the type of amine connected to the amide moiety, that is, morpholine or piperidine and by the position and electronic properties of substituents on the benzyl group connected to 1,2,3-triazole ring. concerning the anti-buche activity, structure-activity relationship studies showed that cl and me substituents, as well as the methylene linker, play a complex and not completely understood role in the enzyme inhibition. from the evaluation of inhibitory activity of the synthesized compounds on bace1, a moderate inhibitory activity of compound 105 was observed (inhibition of 28.69% and 13.97% at 50 and 10 μm, respectively). nevertheless, compound 105 did not show neuroprotective action on pc12 cells exposed to aβ25-35. then, in vivo evaluation of compound 105 using the morrison water maze method [162] was made and valuable results based on memory improvement in scopolamine-induced impairment were observed. similarly, rastegari and collaborators synthesized a series of 1,2,3-triazole-chromenone carboxamide derivatives and investigated their potential as anti-alzheimer's agents, in terms of inhibitory activity against ache, buche and bace1, besides their neuroprotective and metal-chelating properties [163] . the anti-ache activity of coumarin-3carboxamide was already known [164] , as well as the ability of the 1,2,3-triazole moiety to enhance achei activity, if linked with tacrine or phenanthridinium derivatives and its bace1 inhibitory potential [165] . in vitro achei and buchei activities of the new compounds were evaluated, keeping donepezil as reference. higher activities were shown by compound 107, bearing 3,4-dimethylbenzyl connected to 1,2,3-triazole moiety and by compound 108, having 3-morpholinopropyl and 2bromobenzyl moieties ( figure 41 ), even if they are much less active than donepezil (ic50=0.027 μm). anti-bche activity was also modest and resulted to be affected by the type of amine connected to the amide moiety, that is, morpholine or piperidine and by the position and electronic properties of substituents on the benzyl group connected to 1,2,3-triazole ring. compound 107 was chosen for bace1 inhibitory activity evaluation, showing only modest results (ic50 = 21.13 μm compared to the reference om99-2 having ic50 = 0.014μm). also, neuroprotective potential of 107 was investigated by comparing 107-treated cells with intact (no intervention), quercetin+h2o2-treated (positive control) and h2o2-treated (negative control) cells. the mentioned compound showed moderate to good neuroprotective activity, not stronger than quercetin. finally, since ros, which are potentially involved in the neurodegenerative process of ad, may be generated from unregulated reaction of molecular oxygen with the redox active metals such as fe, cu and zn, the metal-chelating properties of 107 toward cu 2+, fe 2+ and zn 2+ were tested in methanol by means of uv-vis spectrophotometry. interaction between 107 and cu 2+ and zn 2+ was detected, whereas no interaction was observed between 107 and fe 2+ . compound 107 was chosen for bace1 inhibitory activity evaluation, showing only modest results (ic50 = 21.13 µm compared to the reference om99-2 having ic50 = 0.014 µm). also, neuroprotective potential of 107 was investigated by comparing 107-treated cells with intact (no intervention), quercetin+h 2 o 2 -treated (positive control) and h 2 o 2 -treated (negative control) cells. the mentioned compound showed moderate to good neuroprotective activity, not stronger than quercetin. finally, since ros, which are potentially involved in the neurodegenerative process of ad, may be generated from unregulated reaction of molecular oxygen with the redox active metals such as fe, cu and zn, the metal-chelating properties of 107 toward cu 2+, fe 2+ and zn 2+ were tested in methanol by means of uv-vis spectrophotometry. interaction between 107 and cu 2+ and zn 2+ was detected, whereas no interaction was observed between 107 and fe 2+ . de souza and co-workers designed and synthesized a series of 3-substituted-7-aminoalcoxycoumarin derivatives (109a-d, 110a-c, 111a-c, figure 42 ) whose achei/buchei activities and antioxidant properties were evaluated [166] . all the compounds showed good inhibitory activity on ache, with potencies in the nanomolar range, whereas their activity against buche was lower (ic 50 between 0.90 to 15.85 µm); 3-(4-(dimethylamino)phenyl)-7-aminoethoxycoumarin (111a) was considered a hit, showing an excellent inhibitory activity (ic 50 = 20 nm) and selectivity towards ache (ic 50 buche/ache = 354) compared to the reference drug donepezil (ic 50 = 6 nm, ic 50 buche/ache = 365). investigation of antioxidant properties showed that only compounds 111a-c presented activity in ferric ion reduction method (frap), whereas series 109a-d and 110a-c did not show significant results, suggesting that the dimethylaminophenyl moiety may be responsible for the antioxidant activity. de souza and co-workers designed and synthesized a series of 3-substituted-7-aminoalcoxycoumarin derivatives (109a-d, 110a-c, 111a-c, figure 42 ) whose achei/buchei activities and antioxidant properties were evaluated [166] . all the compounds showed good inhibitory activity on ache, with potencies in the nanomolar range, whereas their activity against buche was lower (ic50 between 0.90 to 15.85 μm); 3-(4-(dimethylamino)phenyl)-7-aminoethoxycoumarin (111a) was considered a hit, showing an excellent inhibitory activity (ic50 = 20 nm) and selectivity towards ache (ic50 buche/ache = 354) compared to the reference drug donepezil (ic50 = 6 nm, ic50 buche/ache = 365). investigation of antioxidant properties showed that only compounds 111a-c presented activity in ferric ion reduction method (frap), whereas series 109a-d and 110a-c did not show significant results, suggesting that the dimethylaminophenyl moiety may be responsible for the antioxidant activity. docking simulations showed that all the compounds were able to bind simultaneously the pas and cationic active site (cas) of the electric eel ache (eeache): the interaction with the cas took place by means of cation-π interaction between piperidinyl group and trp86. compounds 111a and 111c showed the ability to give a π-stacking interaction in the pas, with trp286. the smaller spacer of 111a allowed the coumarin moiety to be located properly in the gorge, achieving h-bonds with tyr337 and phe295. this is probably the reason for the most efficient binding mode (and consequently the best activity) to eeache of compounds with a short spacer. yang and his group synthesized a series of twenty-four 3-aryl coumarin derivatives and tested their cholinesterase inhibitory activity, monoamine oxidase (mao) inhibitory activity and antioxidant activity in vitro [167] . as far as cholinesterase inhibition is concerned, most of the mentioned compounds showed moderate activity. compound 117 ( figure 43 ) exhibited a strong activity (ic50 = 3.04 ± 0.32 μm), whereas compound 116 showed selectivity towards ache. compound 114 was more active against buche (ic50 = 2.76 ± 0.57 μm) than donepezil, whereas compounds 112, 113 and 115 showed selectivity towards buche. 3-arylcoumarins bearing hydroxy group both at r5 and r6 positions displayed higher activity respect to the mono-substituted counterparts, especially towards ache, whereas no significant impact on buche inhibition was observed. docking simulations showed that all the compounds were able to bind simultaneously the pas and cationic active site (cas) of the electric eel ache (eeache): the interaction with the cas took place by means of cation-π interaction between piperidinyl group and trp86. compounds 111a and 111c showed the ability to give a π-stacking interaction in the pas, with trp286. the smaller spacer of 111a allowed the coumarin moiety to be located properly in the gorge, achieving h-bonds with tyr337 and phe295. this is probably the reason for the most efficient binding mode (and consequently the best activity) to eeache of compounds with a short spacer. yang and his group synthesized a series of twenty-four 3-aryl coumarin derivatives and tested their cholinesterase inhibitory activity, monoamine oxidase (mao) inhibitory activity and antioxidant activity in vitro [167] . as far as cholinesterase inhibition is concerned, most of the mentioned compounds showed moderate activity. compound 117 ( figure 43 ) exhibited a strong activity (ic 50 = 3.04 ± 0.32 µm), whereas compound 116 showed selectivity towards ache. compound 114 was more active against buche (ic 50 = 2.76 ± 0.57 µm) than donepezil, whereas compounds 112, 113 and 115 showed selectivity towards buche. 3-arylcoumarins bearing hydroxy group both at r 5 and r 6 positions displayed higher activity respect to the mono-substituted counterparts, especially towards ache, whereas no significant impact on buche inhibition was observed. antioxidant activity in vitro [167] . as far as cholinesterase inhibition is concerned, most of the mentioned compounds showed moderate activity. compound 117 ( figure 43 ) exhibited a strong activity (ic50 = 3.04 ± 0.32 μm), whereas compound 116 showed selectivity towards ache. compound 114 was more active against buche (ic50 = 2.76 ± 0.57 μm) than donepezil, whereas compounds 112, 113 and 115 showed selectivity towards buche. 3-arylcoumarins bearing hydroxy group both at r5 and r6 positions displayed higher activity respect to the mono-substituted counterparts, especially towards ache, whereas no significant impact on buche inhibition was observed. as mentioned, mao-inhibitory activity was evaluated as well. in fact, mao is one of the enzymes responsible for oxidative stress, which is another factor involved in the neurodegenerative process characterizing ad and different studies identified various che/mao inhibitors as tools for ad treatment, showing positive results in clinical trials [168] . in yang's work, 3-arylcoumarins anti-mao activity was compared to that of rasagiline (a selective mao-b inhibitor): almost half of the compounds showed relevant activity [167] . among them, compound 117 was the most promising, with an ic 50 = 27.03 ± 0.50 µm, though weaker than rasagiline (ic 50 = 0.125 ± 0.005 µm). again, the presence of r 5 , r 6 hydroxy groups provided better mao inhibitory activity. finally, the antioxidant power of 3-arylcoumarins was studied by means of ferric ion reduction method (frap), using vitamin c as a reference. compound 117 resulted again the most active (frap value = 41.42 ± 0.35), also showing a certain activity in vivo, when tested on zebrafish, leading to an increase of total distance of zebrafish movement proportional to the concentration of compound used. in 2017, joubert and collaborators designed and synthesized a series of 7-substituted coumarins (118-146, figure 44 ), consisting in a coumarin motif (mao inhibitor) condensed with a benzyl-, piperidinyl-, n-benzylpiperidinylor p-bromo-n-benzylpiperizinyl moiety, which resemble the n-benzylpiperidine function present in donepezil (ache inhibitor), connected via an alkyl ether linkage at position 7 [169] . their biological activities were evaluated in terms of mao and che inhibitory potential. inhibition of hmao was achieved from all the designed compounds, which also showed selectivity towards mao-b. the benzyloxy series showed higher activity, in some cases even better than the reference selegiline (ic 50 = 0.008 µm), with ic 50 values in the nanomolar range (0.5-73 nm). piperidinyl-, n-benzylpiperidinyl-or p-bromo-n-benzylpiperizinyl moiety, which resemble the nbenzylpiperidine function present in donepezil (ache inhibitor), connected via an alkyl ether linkage at position 7 [169] . their biological activities were evaluated in terms of mao and che inhibitory potential. inhibition of hmao was achieved from all the designed compounds, which also showed selectivity towards mao-b. the benzyloxy series showed higher activity, in some cases even better than the reference selegiline (ic50 = 0.008 μm), with ic50 values in the nanomolar range (0.5-73 nm). . docking studies showed that 136 binds the substrate cavity through the coumarin ring, whereas the benzyl moiety occupies the entrance cavity. in addition, 136 was able to bind both the cas and pas of cholinesterase, which suggested that it could interfere with pas-induced β-amyloid aggregation. a different approach was followed by shi and collaborators, who designed four derivatives obtained by coupling two pharmacophores (carbazole and coumarin) to obtain potential multitarget agents for the treatment of ad [170] . the aim was to exploit the biological activities of both the mentioned moieties: on one hand coumarins are known to have inhibitory activity on ache, buche and mao, besides antioxidant properties; on the other hand, carbazole exhibits antioxidant activity [171] and the ability to inhibit aβ aggregation [172] . in addition, carbazole derivatives are reported to have inhibitory effect on ches, thus providing neuroprotection from β-amyloid toxicity [173] . thus, compounds 147a-d ( figure 45 ) were synthesized, characterized and their biological activities were evaluated: anticholinesterase activity was tested on eeache and on hache, using ellman's method [159] , keeping tacrine as reference drug. whereas all derivatives showed dose-dependent inhibitory activity on eeache (compound 147d resulted the best with an ic 50 of 3.75 µm), on hache they exhibited weak effects (147b ic 50 = 76.63 µm, 147d ic 50 = 70.51 µm). none of the tested compounds inhibited eqbuche or hbuche more than 30%, which means that compounds 147b and 147d showed selectivity for ache over buche. synthesized, characterized and their biological activities were evaluated: anticholinesterase activity was tested on eeache and on hache, using ellman's method [159] , keeping tacrine as reference drug. whereas all derivatives showed dose-dependent inhibitory activity on eeache (compound 147d resulted the best with an ic50 of 3.75 μm), on hache they exhibited weak effects (147b ic50 = 76.63 μm, 147d ic50 = 70.51 μm). none of the tested compounds inhibited eqbuche or hbuche more than 30%, which means that compounds 147b and 147d showed selectivity for ache over buche. as the alkyl linker length increased, the anti-cholinesterase activity improved, probably because a 5-methylene chain allowed the carbazole and coumarin moieties to bind both the cas and the pas, respectively. antioxidant properties were evaluated through the orac-fl method (oxygen radical absorbance capacity by fluorescein) [174] , using trolox (vitamin e analogue) as a standard; none of the tested compounds showed significant activity. among the tested derivatives, compound 147d resulted a promising lead candidate for the treatment of ad. epilepsy is a widespread neurological disorder, characterized by periodic and unpredictable attacks, involving seizures and/or transient behavioral changes. its pathogenesis has not been completely clarified yet; it is known, however, that an impairment between excitatory and inhibitory neurotransmission is involved [175] [176] [177] [178] [179] here, we report some recent advances in the use of coumarins as anticonvulsant compounds. abd-allah and collaborators recently studied the anticonvulsant activity of a series of coumarin derivatives, achieved by merging two or more pharmacophoric scaffolds in order to create new chemical entities with an improved biological activity [180] . the compounds here described possess all the necessary elements to exert anticonvulsant activity: a lipophilic aryl ring, a hydrogen-bonding domain and an electron-donor moiety [178, 179, 181, 182] . all the compounds were initially screened (phase i) using two standard animal seizure models, subcutaneous pentylenetetrazole (scptz) and maximal electric shock (mes) seizure tests using ethosuximide as reference drug. an assessment of the potential neurotoxicity was also done by means of rotarod test. phase ii consisted in the determination of ed50 value for compounds that conferred 100% protection in one or both tests. in the end, gaba level measurements were carried out in whole mouse brain for the most active compounds, using gabapentin as a reference drug. the results of phase i tests showed that all the tested compounds had protective activity against scptz-induced absence epilepsy (variable results in the range of 17-100% protection). among them, 148, 149 and 150 ( figure 46 ) were the most active (100% protection) at 0.238, 0.239 and 0.283 mmol/kg, meaning that the compounds are 1.49, 1.48, 1.25 folds more potent than ethosuximide, respectively. as the alkyl linker length increased, the anti-cholinesterase activity improved, probably because a 5-methylene chain allowed the carbazole and coumarin moieties to bind both the cas and the pas, respectively. antioxidant properties were evaluated through the orac-fl method (oxygen radical absorbance capacity by fluorescein) [174] , using trolox (vitamin e analogue) as a standard; none of the tested compounds showed significant activity. among the tested derivatives, compound 147d resulted a promising lead candidate for the treatment of ad. epilepsy is a widespread neurological disorder, characterized by periodic and unpredictable attacks, involving seizures and/or transient behavioral changes. its pathogenesis has not been completely clarified yet; it is known, however, that an impairment between excitatory and inhibitory neurotransmission is involved [175] [176] [177] [178] [179] here, we report some recent advances in the use of coumarins as anticonvulsant compounds. abd-allah and collaborators recently studied the anticonvulsant activity of a series of coumarin derivatives, achieved by merging two or more pharmacophoric scaffolds in order to create new chemical entities with an improved biological activity [180] . the compounds here described possess all the necessary elements to exert anti-convulsant activity: a lipophilic aryl ring, a hydrogen-bonding domain and an electron-donor moiety [178, 179, 181, 182] . all the compounds were initially screened (phase i) using two standard animal seizure models, subcutaneous pentylenetetrazole (scptz) and maximal electric shock (mes) seizure tests using ethosuximide as reference drug. an assessment of the potential neurotoxicity was also done by means of rotarod test. phase ii consisted in the determination of ed 50 value for compounds that conferred 100% protection in one or both tests. in the end, gaba level measurements were carried out in whole mouse brain for the most active compounds, using gabapentin as a reference drug. the results of phase i tests showed that all the tested compounds had protective activity against scptz-induced absence epilepsy (variable results in the range of 17-100% protection). among them, 148, 149 and 150 ( figure 46 ) were the most active (100% protection) at 0.238, 0.239 and 0.283 mmol/kg, meaning that the compounds are 1.49, 1.48, 1.25 folds more potent than ethosuximide, respectively. in the mes-induced seizures though, all the compounds failed in completely protecting the animals. the best profile was exhibited by compound 151 (figure 46 ) which was capable of a 50% protection at 2.1 mmol/kg. a quantitative determination of ed 50 values was carried out for compounds 148, 149 and 150, which were able to fully protect animals in the scptz test. compound 148 was found to be the most active with an ed 50 of 54.86 mg/kg (0.131 mmol/kg). consequently, it was chosen for further investigation to elucidate the mechanism of action, which was assessed through an evaluation of gaba levels in mice brain. as a result, the proposed mechanism for compound 148 is a gaba-mediated one, perhaps non-vesicular release of gaba, gaba a receptor activation or gaba b receptor inhibition; probably an enhanced synthesis or reduced metabolism of gaba are also involved. the most active with an ed50 of 54.86 mg/kg (0.131 mmol/kg). consequently, it was chosen for further investigation to elucidate the mechanism of action, which was assessed through an evaluation of gaba levels in mice brain. as a result, the proposed mechanism for compound 148 is a gabamediated one, perhaps non-vesicular release of gaba, gabaa receptor activation or gabab receptor inhibition; probably an enhanced synthesis or reduced metabolism of gaba are also involved. a similar bivalent drug approach was followed by mohammadi-khanaposhtani and collaborators, who synthesized a series of coumarin-1,2,4-oxadiazole derivatives in order to create a new chemical entity with better anticonvulsant profile than coumarin and oxadiazole alone [183] . in fact, different 5-member heterocyclic rings-containing compounds such as oxadiazoles, triazoles and thiadiazoles were reported to have good anticonvulsant activity [184] [185] [186] through benzodiazepine (bdz) receptor [187] . the activity of the new derivatives was tested using ptz-and mes-induced seizures in mice, keeping diazepam as a reference drug. most of the new compounds did not show activity against ptz-induced seizures, except for three of them, 152a, 152b and 152c (figure 47 ), being 152b the most active (25% of protection using 10 mg/kg). compounds 152d, 152e and 152f ( figure 47 ) showed a 100% protection against mes-induced seizures at the doses of 7, 40 and 20 mg/kg, respectively (it should be considered that diazepam shows 100% protection at 2 mg/ml) [188] . compound 152d, which showed the best activity, was characterized by the absence of substituents on position 4 of the coumarin ring and by a 4-chloroaryl group connected to the 1, 2, 4-oxadiazole ring. the most active compounds 152d and 152e were used to investigate the mechanism of action; to do so, the effect of flumazenil (a bdz receptor antagonist) on their activity was evaluated. flumazenil antagonized both 152d and 152e, confirming that these compounds act as bzs receptor agonists. finally, in vivo neurotoxicity of compounds 152d and 152e was assessed and the tested compounds gave less neurological deficits that the reference drug diazepam. a similar bivalent drug approach was followed by mohammadi-khanaposhtani and collaborators, who synthesized a series of coumarin-1,2,4-oxadiazole derivatives in order to create a new chemical entity with better anticonvulsant profile than coumarin and oxadiazole alone [183] . in fact, different 5-member heterocyclic rings-containing compounds such as oxadiazoles, triazoles and thiadiazoles were reported to have good anticonvulsant activity [184] [185] [186] through benzodiazepine (bdz) receptor [187] . the activity of the new derivatives was tested using ptz-and mes-induced seizures in mice, keeping diazepam as a reference drug. most of the new compounds did not show activity against ptz-induced seizures, except for three of them, 152a, 152b and 152c (figure 47 ), being 152b the most active (25% of protection using 10 mg/kg). compounds 152d, 152e and 152f ( figure 47 ) showed a 100% protection against mes-induced seizures at the doses of 7, 40 and 20 mg/kg, respectively (it should be considered that diazepam shows 100% protection at 2 mg/ml) [188] . compound 152d, which showed the best activity, was characterized by the absence of substituents on position 4 of the coumarin ring and by a 4-chloroaryl group connected to the 1, 2, 4-oxadiazole ring. the most active compounds 152d and 152e were used to investigate the mechanism of action; to do so, the effect of flumazenil (a bdz receptor antagonist) on their activity was evaluated. flumazenil antagonized both 152d and 152e, confirming that these compounds act as bzs receptor agonists. finally, in vivo neurotoxicity of compounds 152d and 152e was assessed and the tested compounds gave less neurological deficits that the reference drug diazepam. a series of 4-amino-3-nitrocoumarins (153a-e, figure 48 ) was synthesized and biologically evaluated by mokrov and co-workers [189] . the anticonvulsant activity was investigated using the mes mice model (grand mal seizures) and the corazole-antagonism test (modelling the so-called petit mal seizure). the only statistically significant result was given by compound 153a at doses in the range of 60-80 mg/kg, as it could increase the animal survival in mes test up to 60% (in the control group survival was 10%). corazole-induced seizures and animals' death were not prevented by compounds 153a, 153c and 153d. compound 153e exhibited good protection potential at 10-40 mg/kg and was able to prevent death in 50-63% of animals. the most active compound in the mes test was 153a, containing a coumarin ring with a 3-nitro group and a γ-aminobutirric acid fragment. the corresponding methyl-ester (153c) did not show any activity, as well as compound 153d, with an additional nitro group. compound 153e, bearing the methyl-ester of gaba pharmacophore and two nitro groups on the coumarin ring, showed the best profile in corazole-antagonism test. the corresponding free carboxylic acid 153d was found to be inactive, as well as compound 153c, having one less nitro group. compound 153a, bearing one nitro group and no substituent on gaba moiety, did not show any corazole-antagonist activity. therefore, it can be speculated that compounds 153a and 153e possess different mechanisms responsible for their anticonvulsant activity and they may be a starting point for further studies on coumarin derivatives as anticonvulsant agents. the recent medical history of anticoagulant drugs has been largely dominated by a simple class of molecules that has been discovered thanks to a mysterious livestock mortality and, later, employed as a powerful rodenticide: coumarins. the anticoagulant activity of coumarins was identified when in 1920′s seemingly healthy cattle of canada and north america died inexplicably for internal hemorrhages. the main cause of this decimation was attributed to a mold infestation of the damp hay, later known as the "sweet clover disease." however, it was not before 1940 that the responsible molecule was identified by karl link and his student harold campbell: it was 3,3'-methylenebis(4a series of 4-amino-3-nitrocoumarins (153a-e, figure 48 ) was synthesized and biologically evaluated by mokrov and co-workers [189] . the anticonvulsant activity was investigated using the mes mice model (grand mal seizures) and the corazole-antagonism test (modelling the so-called petit mal seizure). the only statistically significant result was given by compound 153a at doses in the range of 60-80 mg/kg, as it could increase the animal survival in mes test up to 60% (in the control group survival was 10%). corazole-induced seizures and animals' death were not prevented by compounds 153a, 153c and 153d. compound 153e exhibited good protection potential at 10-40 mg/kg and was able to prevent death in 50-63% of animals. the most active compound in the mes test was 153a, containing a coumarin ring with a 3-nitro group and a γ-aminobutirric acid fragment. the corresponding methyl-ester (153c) did not show any activity, as well as compound 153d, with an additional nitro group. compound 153e, bearing the methyl-ester of gaba pharmacophore and two nitro groups on the coumarin ring, showed the best profile in corazole-antagonism test. the corresponding free carboxylic acid 153d was found to be inactive, as well as compound 153c, having one less nitro group. compound 153a, bearing one nitro group and no substituent on gaba moiety, did not show any corazole-antagonist activity. therefore, it can be speculated that compounds 153a and 153e possess different mechanisms responsible for their anticonvulsant activity and they may be a starting point for further studies on coumarin derivatives as anticonvulsant agents. a series of 4-amino-3-nitrocoumarins (153a-e, figure 48 ) was synthesized and biologically evaluated by mokrov and co-workers [189] . the anticonvulsant activity was investigated using the mes mice model (grand mal seizures) and the corazole-antagonism test (modelling the so-called petit mal seizure). the only statistically significant result was given by compound 153a at doses in the range of 60-80 mg/kg, as it could increase the animal survival in mes test up to 60% (in the control group survival was 10%). corazole-induced seizures and animals' death were not prevented by compounds 153a, 153c and 153d. compound 153e exhibited good protection potential at 10-40 mg/kg and was able to prevent death in 50-63% of animals. the most active compound in the mes test was 153a, containing a coumarin ring with a 3-nitro group and a γ-aminobutirric acid fragment. the corresponding methyl-ester (153c) did not show any activity, as well as compound 153d, with an additional nitro group. compound 153e, bearing the methyl-ester of gaba pharmacophore and two nitro groups on the coumarin ring, showed the best profile in corazole-antagonism test. the corresponding free carboxylic acid 153d was found to be inactive, as well as compound 153c, having one less nitro group. compound 153a, bearing one nitro group and no substituent on gaba moiety, did not show any corazole-antagonist activity. therefore, it can be speculated that compounds 153a and 153e possess different mechanisms responsible for their anticonvulsant activity and they may be a starting point for further studies on coumarin derivatives as anticonvulsant agents. the recent medical history of anticoagulant drugs has been largely dominated by a simple class of molecules that has been discovered thanks to a mysterious livestock mortality and, later, employed as a powerful rodenticide: coumarins. the anticoagulant activity of coumarins was identified when in 1920′s seemingly healthy cattle of canada and north america died inexplicably for internal hemorrhages. the main cause of this decimation was attributed to a mold infestation of the damp hay, later known as the "sweet clover disease." however, it was not before 1940 that the responsible molecule was identified by karl link and his student harold campbell: it was 3,3'-methylenebis(4 the recent medical history of anticoagulant drugs has been largely dominated by a simple class of molecules that has been discovered thanks to a mysterious livestock mortality and, later, employed as a powerful rodenticide: coumarins. the anticoagulant activity of coumarins was identified when in 1920 s seemingly healthy cattle of canada and north america died inexplicably for internal hemorrhages. the main cause of this decimation was attributed to a mold infestation of the damp hay, later known as the "sweet clover disease." however, it was not before 1940 that the responsible molecule was identified by karl link and his student harold campbell: it was 3,3'-methylenebis(4-hydroxycoumarin), later known as dicoumarol. further studies by link's team brought to the discovery of warfarin in 1948 (so named from warf, wisconsin alumni research foundation, that financed the project), approved as a rodenticide in the usa in 1952 and for anticoagulation therapy in human in 1954, under the name of coumadin. currently, warfarin is one of the most widely used anticoagulation drug (in the uk it has been estimated that at least 1% of the population and 8% of people over 80 years are taking warfarin), together with other coumarin derivatives like dicumarol and acenocoumarol ( figure 49 ) [18, [190] [191] [192] . hydroxycoumarin), later known as dicoumarol. further studies by link's team brought to the discovery of warfarin in 1948 (so named from warf, wisconsin alumni research foundation, that financed the project), approved as a rodenticide in the usa in 1952 and for anticoagulation therapy in human in 1954, under the name of coumadin. currently, warfarin is one of the most widely used anticoagulation drug (in the uk it has been estimated that at least 1% of the population and 8% of people over 80 years are taking warfarin), together with other coumarin derivatives like dicumarol and acenocoumarol ( figure 49 ) [18, [190] [191] [192] . warfarin and other anticoagulant coumarins are vitamin-k antagonists (vkas). indeed, due to the structural similarity with vitamin-k, the compounds block the vitamin-k dependent pathways of coagulation, involving several factors (ii, vii, ix and x). despite the efficacy and the advantages of an oral therapy, warfarin is not devoid of side effects, mainly associated with bleeding and complications, like the narrow therapeutic range and interindividual genetic difference in pharmacokinetics, which requires a continuous monitoring of the patient [193, 194] . for this reason, the research of new safer and efficient compounds lead to the discovery of a novel vka, tecarfarin (ati-5923, figure 50 ), currently under development [195] . tecarfarin is active after oral administration and acts as a vitamin-k epoxide reductase (vkor) inhibitor; unlike warfarin, is not metabolized by the cytochrome p450 system but by human carboxylesterase-2 (hce-2) in hepatic microsomes. consequently, drug-drug or food-drug interactions are avoided, as well as genetic variability of cyp-450 system, providing a more stable anticoagulation effect compared to warfarin [196] . a detailed study on pharmacokinetics and pharmacodynamics of tecarfarin had been conducted on healthy patients by albrecht et al., together with the recent phase i study on its tolerability among patients with severe kidney disease [197, 198] . tecarfarin has the potentiality to be a valid substitute of warfarin in the oral therapy of thromboembolic disease. warfarin and other anticoagulant coumarins are vitamin-k antagonists (vkas). indeed, due to the structural similarity with vitamin-k, the compounds block the vitamin-k dependent pathways of coagulation, involving several factors (ii, vii, ix and x). despite the efficacy and the advantages of an oral therapy, warfarin is not devoid of side effects, mainly associated with bleeding and complications, like the narrow therapeutic range and interindividual genetic difference in pharmacokinetics, which requires a continuous monitoring of the patient [193, 194] . for this reason, the research of new safer and efficient compounds lead to the discovery of a novel vka, tecarfarin (ati-5923, figure 50 ), currently under development [195] . tecarfarin is active after oral administration and acts as a vitamin-k epoxide reductase (vkor) inhibitor; unlike warfarin, is not metabolized by the cytochrome p450 system but by human carboxylesterase-2 (hce-2) in hepatic microsomes. consequently, drug-drug or food-drug interactions are avoided, as well as genetic variability of cyp-450 system, providing a more stable anticoagulation effect compared to warfarin [196] . a detailed study on pharmacokinetics and pharmacodynamics of tecarfarin had been conducted on healthy patients by albrecht et al., together with the recent phase i study on its tolerability among patients with severe kidney disease [197, 198] . tecarfarin has the potentiality to be a valid substitute of warfarin in the oral therapy of thromboembolic disease. hydroxycoumarin), later known as dicoumarol. further studies by link's team brought to the discovery of warfarin in 1948 (so named from warf, wisconsin alumni research foundation, that financed the project), approved as a rodenticide in the usa in 1952 and for anticoagulation therapy in human in 1954, under the name of coumadin. currently, warfarin is one of the most widely used anticoagulation drug (in the uk it has been estimated that at least 1% of the population and 8% of people over 80 years are taking warfarin), together with other coumarin derivatives like dicumarol and acenocoumarol ( figure 49 ) [18, [190] [191] [192] . warfarin and other anticoagulant coumarins are vitamin-k antagonists (vkas). indeed, due to the structural similarity with vitamin-k, the compounds block the vitamin-k dependent pathways of coagulation, involving several factors (ii, vii, ix and x). despite the efficacy and the advantages of an oral therapy, warfarin is not devoid of side effects, mainly associated with bleeding and complications, like the narrow therapeutic range and interindividual genetic difference in pharmacokinetics, which requires a continuous monitoring of the patient [193, 194] . for this reason, the research of new safer and efficient compounds lead to the discovery of a novel vka, tecarfarin (ati-5923, figure 50 ), currently under development [195] . tecarfarin is active after oral administration and acts as a vitamin-k epoxide reductase (vkor) inhibitor; unlike warfarin, is not metabolized by the cytochrome p450 system but by human carboxylesterase-2 (hce-2) in hepatic microsomes. consequently, drug-drug or food-drug interactions are avoided, as well as genetic variability of cyp-450 system, providing a more stable anticoagulation effect compared to warfarin [196] . a detailed study on pharmacokinetics and pharmacodynamics of tecarfarin had been conducted on healthy patients by albrecht et al., together with the recent phase i study on its tolerability among patients with severe kidney disease [197, 198] . tecarfarin has the potentiality to be a valid substitute of warfarin in the oral therapy of thromboembolic disease. another approach reported in literature is the chemical modification of the coumarin scaffold by conjugation of 7-hydroxylcoumarin and 7-hydroxy-4-methylcoumarin with some derivatives of salicylic acid. among the compounds evaluated by bang and co-workers in 2019, derivatives 154 and 155 ( figure 51 ) showed high anticoagulant activity, with an increased prothrombin time (pt) of 10.88 ± 0.56 sec and 13.10 ± 3.56 sec, respectively. both compounds resulted 1.5 times more active than warfarin (pt 7.97 ± 1.93) [199] . structural modifications of the 4-hydroxycoumarin core was also the rational of montagut-romans et al., who in 2017 explored the potentiality given by modifications performed on c3 position by introducing a side chain (with at most one unsaturation) structurally related to vitamin-k cofactor [200] . the underlying premise was the sar study performed by gebaur in 2007, which pointed out that the activity of 4-hydroxycoumarin was enhanced only by structural modification for c3 position by isoprenyl motifs [201] . in this contest, 14 functionalized 4-hydroxycoumarins with alkyl chains of different length, both linear and branched, were synthesized and their activity was evaluated in vitro and ex vivo (phenprocoumon was included in the test as internal standard). the ability to inhibit vkorc1 in rat liver microsomes was evaluated in vitro and, except for two compounds, the c3-alkyl derivatives showed a sub-micromolar activity (from 20 nm to 200 nm) overcoming the benchmark compound phenprocoumon. further ex vivo studies assessed the ability to increase in vivo the prothrombin time (pt) and compounds 156a and 156b ( figure 52 ) showed a promising anticoagulant activity after 24 h. it is possible that the presence of the halogen atom protects the drug from liver metabolism. despite the interesting anticoagulant activity, follow-up studies on the liver metabolism are necessary to determine if these molecules are substrate of cyp2c9, to which is to attribute the variability in the dosage of oral vitamin-k antagonists, due to its polymorphism [202] . figure 53 ) presented a remarkable anticoagulant activity (pt = 41.2s and tt 128.5s) and no significant hepatic or renal toxicity when compared to warfarin (pt = 55.7s and tt 80.6s) [203] . although further studies are necessary to understand the mode of action of compound 157, it could be a promising anticoagulant agent for preclinical studies. structural modifications of the 4-hydroxycoumarin core was also the rational of montagut-romans et al., who in 2017 explored the potentiality given by modifications performed on c3 position by introducing a side chain (with at most one unsaturation) structurally related to vitamin-k cofactor [200] . the underlying premise was the sar study performed by gebaur in 2007, which pointed out that the activity of 4-hydroxycoumarin was enhanced only by structural modification for c3 position by isoprenyl motifs [201] . in this contest, 14 functionalized 4-hydroxycoumarins with alkyl chains of different length, both linear and branched, were synthesized and their activity was evaluated in vitro and ex vivo (phenprocoumon was included in the test as internal standard). the ability to inhibit vkorc1 in rat liver microsomes was evaluated in vitro and, except for two compounds, the c3-alkyl derivatives showed a sub-micromolar activity (from 20 nm to 200 nm) overcoming the benchmark compound phenprocoumon. further ex vivo studies assessed the ability to increase in vivo the prothrombin time (pt) and compounds 156a and 156b ( figure 52 ) showed a promising anticoagulant activity after 24 h. it is possible that the presence of the halogen atom protects the drug from liver metabolism. despite the interesting anticoagulant activity, follow-up studies on the liver metabolism are necessary to determine if these molecules are substrate of cyp2c9, to which is to attribute the variability in the dosage of oral vitamin-k antagonists, due to its polymorphism [202] . another approach reported in literature is the chemical modification of the coumarin scaffold by conjugation of 7-hydroxylcoumarin and 7-hydroxy-4-methylcoumarin with some derivatives of salicylic acid. among the compounds evaluated by bang and co-workers in 2019, derivatives 154 and 155 ( figure 51 ) showed high anticoagulant activity, with an increased prothrombin time (pt) of 10.88 ± 0.56 sec and 13.10 ± 3.56 sec, respectively. both compounds resulted 1.5 times more active than warfarin (pt 7.97 ± 1.93) [199] . structural modifications of the 4-hydroxycoumarin core was also the rational of montagut-romans et al., who in 2017 explored the potentiality given by modifications performed on c3 position by introducing a side chain (with at most one unsaturation) structurally related to vitamin-k cofactor [200] . the underlying premise was the sar study performed by gebaur in 2007, which pointed out that the activity of 4-hydroxycoumarin was enhanced only by structural modification for c3 position by isoprenyl motifs [201] . in this contest, 14 functionalized 4-hydroxycoumarins with alkyl chains of different length, both linear and branched, were synthesized and their activity was evaluated in vitro and ex vivo (phenprocoumon was included in the test as internal standard). the ability to inhibit vkorc1 in rat liver microsomes was evaluated in vitro and, except for two compounds, the c3-alkyl derivatives showed a sub-micromolar activity (from 20 nm to 200 nm) overcoming the benchmark compound phenprocoumon. further ex vivo studies assessed the ability to increase in vivo the prothrombin time (pt) and compounds 156a and 156b ( figure 52 ) showed a promising anticoagulant activity after 24 h. it is possible that the presence of the halogen atom protects the drug from liver metabolism. despite the interesting anticoagulant activity, follow-up studies on the liver metabolism are necessary to determine if these molecules are substrate of cyp2c9, to which is to attribute the variability in the dosage of oral vitamin-k antagonists, due to its polymorphism [202] . figure 53 ) presented a remarkable anticoagulant activity (pt = 41.2s and tt 128.5s) and no significant hepatic or renal toxicity when compared to warfarin (pt = 55.7s and tt 80.6s) [203] . although further studies are necessary to understand the mode of action of compound 157, it could be a promising anticoagulant agent for preclinical studies. figure 53 ) presented a remarkable anticoagulant activity (pt = 41.2s and tt 128.5s) and no significant hepatic or renal toxicity when compared to warfarin (pt = 55.7s and tt 80.6s) [203] . although further studies are necessary to understand the mode of action of compound 157, it could be a promising anticoagulant agent for preclinical studies. diabetes is a chronic metabolic disease characterized by high blood sugar levels and is generally caused by an insufficient production of insulin by β-pancreatic cells or by the inability of human body to use this hormone. the consequences of diabetes might be very serious: blindness, kidney failure, stroke, heart attacks, lower limb amputation [204] [205] [206] diabetes is a chronic metabolic disease characterized by high blood sugar levels and is generally caused by an insufficient production of insulin by β-pancreatic cells or by the inability of human body to use this hormone. the consequences of diabetes might be very serious: blindness, kidney failure, stroke, heart attacks, lower limb amputation [204] [205] [206] menteşe et al. synthesized a novel series of n -(2-(3,5-disubstituted-4h-1,2,4-triazol-4-yl)acetyl)-6/7/8 substituted-2-oxo-2h-chromen-3-carbohydrazides (158a-e, 159a-e, figure 54 ) [207] , merging the 1,2,4-triazole and the coumarin moieties, both characterized by a wide range of biological activities (including inhibition of α-glucosidases) and low toxicity profiles [208] [209] [210] [211] [212] [213] . then, their activity on α-glucosidases was studied, evaluating the enzyme inhibition in the presence of pnpg (p-nitrophenyl-α-d-glucopyranoside) as a substrate in the buffer (ph 6.8). among the new compounds, four molecules showed high inhibition activity, compared to acarbose (ic 50 = 8.85 ± 0.23 µg/ml): 158d (ic 50 = 4.28 ± 0.10 µg/ml), 158e (ic 50 = 0.96 ± 0.02 µg/ml), 159d (ic 50 = 6.75 ± 0.10 µg/ml) and 159e (ic 50 = 1.44 ± 0.06 µg/ml). diabetes is a chronic metabolic disease characterized by high blood sugar levels and is generally caused by an insufficient production of insulin by β-pancreatic cells or by the inability of human body to use this hormone. the consequences of diabetes might be very serious: blindness, kidney failure, stroke, heart attacks, lower limb amputation [204] [205] [206] menteşe et al. synthesized a novel series of n'-(2-(3,5-disubstituted-4h-1,2,4-triazol-4-yl)acetyl)-6/7/8 substituted-2-oxo-2h-chromen-3-carbohydrazides (158a-e, 159a-e, figure 54 ) [207] , merging the 1,2,4-triazole and the coumarin moieties, both characterized by a wide range of biological activities (including inhibition of α-glucosidases) and low toxicity profiles [208] [209] [210] [211] [212] [213] . then, their activity on α-glucosidases was studied, evaluating the enzyme inhibition in the presence of pnpg (p-nitrophenyl-α-d-glucopyranoside) as a substrate in the buffer (ph 6.8). among the new compounds, four molecules showed high inhibition activity, compared to acarbose (ic50 = 8.85 ± 0.23 μg/ml): 158d (ic50 = 4.28 ± 0.10 μg/ml), 158e (ic50 = 0.96 ± 0.02 μg/ml), 159d (ic50 = 6.75 ± 0.10 μg/ml) and 159e (ic50 = 1.44 ± 0.06 μg/ml). compounds 158e and 159e resulted the most active, probably because of the metoxy-group at position 8 of the coumarin ring. derivatives without substituents on positions 3 and 5 of the phenyl ring linked to the triazole nucleus resulted more active than compounds bearing a chlorine atom or a phenyl moiety on such positions. according to kinetic studies, the tested compounds inhibit αglucosidases in a competitive way. other studies focused on coumarins-mediated inhibition of αglucosidases were carried out by different groups. hu and collaborators synthesized through microwave radiation heating a new series of more than forty 3-arylcoumarins which were screened for antioxidant activity, α-glucosidases inhibition and advanced glycation end-products (ages) formation inhibition [214] . only eight of the synthesized compounds (160-167, figure 55 ) exhibited moderate to high inhibitory activity on α-glucosidase. compounds 158e and 159e resulted the most active, probably because of the metoxy-group at position 8 of the coumarin ring. derivatives without substituents on positions 3 and 5 of the phenyl ring linked to the triazole nucleus resulted more active than compounds bearing a chlorine atom or a phenyl moiety on such positions. according to kinetic studies, the tested compounds inhibit α-glucosidases in a competitive way. other studies focused on coumarins-mediated inhibition of α-glucosidases were carried out by different groups. hu and collaborators synthesized through microwave radiation heating a new series of more than forty 3-arylcoumarins which were screened for antioxidant activity, α-glucosidases inhibition and advanced glycation end-products (ages) formation inhibition [214] . only eight of the synthesized compounds (160-167, figure 55 ) exhibited moderate to high inhibitory activity on α-glucosidase. compound 165 was the most promising (ic50 = 1.37 ± 0.67 μm), with a α-glucosidase inhibitory activity slightly weaker than acarbose (ic50 = 0.050 ± 0.003 μm). from an extensive sar study, it emerged that the 7-hydroxy group is important for the inhibition of α-glucosidase. compounds 160, 163,164, 165 and 166 were then tested in vivo: none of them showed toxicity on mice (ld50 > 5000 mg/kg). the mentioned compounds were also tested on streptozocin-induced diabetic mice. compound 166 showed the best profile, exhibiting a strong reduction of glucose blood levels. oral daily administration of 166 ( compound 165 was the most promising (ic 50 = 1.37 ± 0.67 µm), with a α-glucosidase inhibitory activity slightly weaker than acarbose (ic 50 = 0.050 ± 0.003 µm). from an extensive sar study, it emerged that the 7-hydroxy group is important for the inhibition of α-glucosidase. compounds 160, 163, 164, 165 and 166 were then tested in vivo: none of them showed toxicity on mice (ld 50 > 5000 mg/kg). the mentioned compounds were also tested on streptozocin-induced diabetic mice. compound 166 showed the best profile, exhibiting a strong reduction of glucose blood levels. oral daily administration of 166 (30 mg/kg/day) restored glucose blood levels near normal values, showing an effect similar to that of the oral antidiabetic glibenclamide. asgari and co-workers synthesized a new series of biscoumarin-1,2,3-triazole derivatives ( figure 56 ) and evaluated their α-glucosidase inhibitory potential, using acarbose as a reference drug [215] . compound 165 was the most promising (ic50 = 1.37 ± 0.67 μm), with a α-glucosidase inhibitory activity slightly weaker than acarbose (ic50 = 0.050 ± 0.003 μm). from an extensive sar study, it emerged that the 7-hydroxy group is important for the inhibition of α-glucosidase. compounds 160, 163,164, 165 and 166 were then tested in vivo: none of them showed toxicity on mice (ld50 > 5000 mg/kg). the mentioned compounds were also tested on streptozocin-induced diabetic mice. compound 166 showed the best profile, exhibiting a strong reduction of glucose blood levels. oral daily administration of 166 (30 mg/kg/day) restored glucose blood levels near normal values, showing an effect similar to that of the oral antidiabetic glibenclamide. asgari and co-workers synthesized a new series of biscoumarin-1,2,3-triazole derivatives ( figure 56 ) and evaluated their α-glucosidase inhibitory potential, using acarbose as a reference drug [215] . here, again, two active moieties, both characterized by a wide range of biological activities, were merged together: the bis-coumarin and the 1,2,3-triazole moieties [216] . all the synthesized compounds showed excellent activities (ic50 between 13.0 ± 1.5 and 75.5 ± 7.0 μm) compared to acarbose (ic50 750.0 ± 12.0). compound 168c, bearing 2-chloro phenyl moiety, resulted the most active. the substitution of the chlorine atom with a methyl group or its shift on the c4 position caused a decrease in activity. moreover, the inhibitory activity seemed to depend importantly on the electron properties of the substituents. from further kinetic studies it emerged that compound 168c inhibits α-glucosidases in a competitive mode (ki = 11 μm). a different therapeutic approach may be the stimulation of insulin secretion. in this perspective, ahmed and collaborators extracted from the aerial parts of clutia lanceolata (a medicinal plant native to sub-saharan africa and the arabian peninsula) twenty-one coumarins, including methyltio-and methylsulfinil-coumarins, thirteen of which were reported for the first time [217] . the structures of these natural compounds were elucidated from 2d-nmr and ms spectra, whereas their anti-diabetic activity was tested measuring the glucose-triggered insulin secretion of freshly isolated murine islets. here, again, two active moieties, both characterized by a wide range of biological activities, were merged together: the bis-coumarin and the 1,2,3-triazole moieties [216] . all the synthesized compounds showed excellent activities (ic 50 between 13.0 ± 1.5 and 75.5 ± 7.0 µm) compared to acarbose (ic 50 750.0 ± 12.0). compound 168c, bearing 2-chloro phenyl moiety, resulted the most active. the substitution of the chlorine atom with a methyl group or its shift on the c4 position caused a decrease in activity. moreover, the inhibitory activity seemed to depend importantly on the electron properties of the substituents. from further kinetic studies it emerged that compound 168c inhibits α-glucosidases in a competitive mode (k i = 11 µm). a different therapeutic approach may be the stimulation of insulin secretion. in this perspective, ahmed and collaborators extracted from the aerial parts of clutia lanceolata (a medicinal plant native to sub-saharan africa and the arabian peninsula) twenty-one coumarins, including methyltio-and methylsulfinil-coumarins, thirteen of which were reported for the first time [217] . the structures of these natural compounds were elucidated from 2d-nmr and ms spectra, whereas their anti-diabetic activity was tested measuring the glucose-triggered insulin secretion of freshly isolated murine islets. the applications and properties of coumarin scaffold have remarkably wide boundaries. coumarin-based compounds have been exploited in numerous research and industrial sectors, as active pharmaceutical ingredients, pesticides, fragrances, dyes for several purposes from laser the applications and properties of coumarin scaffold have remarkably wide boundaries. coumarin-based compounds have been exploited in numerous research and industrial sectors, as active pharmaceutical ingredients, pesticides, fragrances, dyes for several purposes from laser technology to organic photoredox catalysis, cell imaging, photocleavable protecting groups and fluorescent biological probes [6, [218] [219] [220] [221] [222] [223] [224] [225] . in the following paragraphs, the most recent applications associated with the photophysical properties of coumarins have been reviewed. the development of a suitable formulation is a crucial step in order to achieve new functional therapeutics. the design of novel strategies aimed at selectively release the bioactive in a specific district at a determinate time to maximize efficacy and reduce off-target adverse effects represents an extremely active research frontline. so far, various stimuli-responsive systems have been considered in therapeutic approaches to regulate the release of the therapeutic cargo, including endogenous stimuli (e.g., ph, enzymes, redox reactions, etc.) and exogenous stimuli (e.g., light, magnetic field, ionizing radiations, etc.) [226, 227] . light-mediated therapies have shown excellent results in achieving on-demand therapeutics and optical tools for studying and controlling complex chemical and biological processes in localized areas, owing to their superior non-invasiveness and spatiotemporal precision upon applying a specific light-irradiation wavelength [227] [228] [229] . one method for the regulation of molecular processes with light is the use of photolabile "protecting" groups in key locations. ideally, this modification completely blocks the activity of any molecule and restores it only with light [230] . coumarins, particularly 4-hydroxymethyl derivatives, are known to undergo photolysis. keeping this concept in mind, several biomolecules of interest have been linked to the coumarin nucleus, mostly as acyl derivatives. then, under uv irradiation, the biomolecules can be released in biological systems. the photophysical parameters of the formed derivatives are determined by different factors as the mode of fusion, the chemical nature of additional rings and the presence of electron-donating and electron-withdrawing substituents [12] . fournier and co-workers in 2013 proposed a series of methyl-coumarins with redshifted absorption. in particular, three compounds (172-174, figure 58 ), were synthetically easily accessible and exhibited a significant action cross section for uncaging with blue-cyan light, whereas their uncaging ability in the uv spectral domain remained low in order to avoid their photoactivation when a properly tuned uv illumination is applied [231] . in the same year, fournier and co-workers further proved that compound 172 was a good blue-absorbing caging group, owing to its strongly donating substituent conjugated to the thiocarbonyl group. moreover, the research team demonstrated that this particular caging group could be used in zebrafish embryos in the context of development biology to perform chromatic orthogonal photoactivation of two biologically active species [232] . in 2017, gandioso and colleagues reported the development of green/red-absorbing chromophores based on coumarin scaffolds that could be useful as photocleavable protecting groups [224] . a series of coumarin derivatives in which the carbonyl of the lactone was replaced by a cyano(4-nitrophenyl)methylene moiety, by condensation of a thiocoumarin precursor with the corresponding arylacetonitrile derivatives, was synthesized and subsequently refined with the insertion of electro-withdrawing groups at the phenyl ring, leading to absorption in the green to red region (175, figure 58 ) [224] . the insertion of more than one electro-withdrawing group (such as -no 2 and -cn) decreased the fluorescence emission, whereas the mononitro-containing coumarin derivatives had a strong emission in the red region upon excitation with green light, as denoted by their significantly large stokes shifts. in order to demonstrate the utility of these new compounds as ppgs, a small collection of coumarin-based photocages of benzoic acid was prepared. thanks to photolysis studies with green light, it was demonstrated that the structure of the coumarin chromophore influenced the rate of the uncaging process. this observation gave the opportunity to exploit these new coumarin scaffolds as caging groups removable with visible light. on the other hand, bojtar and colleagues proposed water soluble red-shifted coumarin caging groups (176-178, figure 58 ), activated with green-light [233] . 58) [224] . the insertion of more than one electro-withdrawing group (such as -no2 and -cn) decreased the fluorescence emission, whereas the mononitro-containing coumarin derivatives had a strong emission in the red region upon excitation with green light, as denoted by their significantly large stokes shifts. in order to demonstrate the utility of these new compounds as ppgs, a small collection of coumarin-based photocages of benzoic acid was prepared. thanks to photolysis studies with green light, it was demonstrated that the structure of the coumarin chromophore influenced the rate of the uncaging process. this observation gave the opportunity to exploit these new coumarin scaffolds as caging groups removable with visible light. on the other hand, bojtar and colleagues proposed water soluble red-shifted coumarin caging groups (176-178, figure 58 ), activated with green-light [233] . the optical properties of coumarins as photo-responsive unites could be also applied to polymers that after a photochemical activation rapidly degrade into small molecules. in 2018, iturmendi and co-workers proposed that, through functionalization of polyphosphazenes with a coumarin-caged amino acid as a pendant group along the backbone, the sensitivity of the polymers to hydrolysis would be accelerated upon irradiation and effectively catalyze its own degradation [234] . coumarins possess a large electron-rich π-π conjugated system with charge transfer properties, reason why coumarin-based fluorophores are widely used for monitoring a variety of biologically important species and biochemical process in living cells, for example as diagnostic agent for detection of biothiols, enzymes, mitochondrial ph values, glucose and ions [3, 222, 235] . in particular, several coumarin scaffolds have been proposed and evaluated for the detection of ions in different fields, from cellular imaging to environmental waters. gong and co-workers based their work on an easily synthesized coumarin-based fluorescent probe (179, figure 59 ) that already was effective in the detection of glutathione (ghs) in the presence of cu 2+ ions, expanding its potentiality to the detection of hypochlorite ions with high selectivity and sensitivity. the probe showed a remarkable fluorescent intensity change in response to hypochlorite ions; moreover, this probe could be applied to detect cloin cells via intracellular fluorescent imaging [236, 237] . given the importance of hypochlorite the optical properties of coumarins as photo-responsive unites could be also applied to polymers that after a photochemical activation rapidly degrade into small molecules. in 2018, iturmendi and co-workers proposed that, through functionalization of polyphosphazenes with a coumarin-caged amino acid as a pendant group along the backbone, the sensitivity of the polymers to hydrolysis would be accelerated upon irradiation and effectively catalyze its own degradation [234] . coumarins possess a large electron-rich π-π conjugated system with charge transfer properties, reason why coumarin-based fluorophores are widely used for monitoring a variety of biologically important species and biochemical process in living cells, for example as diagnostic agent for detection of biothiols, enzymes, mitochondrial ph values, glucose and ions [3, 222, 235] . in particular, several coumarin scaffolds have been proposed and evaluated for the detection of ions in different fields, from cellular imaging to environmental waters. gong and co-workers based their work on an easily synthesized coumarin-based fluorescent probe (179, figure 59 ) that already was effective in the detection of glutathione (ghs) in the presence of cu 2+ ions, expanding its potentiality to the detection of hypochlorite ions with high selectivity and sensitivity. the probe showed a remarkable fluorescent intensity change in response to hypochlorite ions; moreover, this probe could be applied to detect clo − in cells via intracellular fluorescent imaging [236, 237] . given the importance of hypochlorite ions both in living systems (being one of the biologically most important reactive oxygens species) and in the environment (owing to its use as disinfectant), in 2019, shangguan and colleagues proposed another probe for this particular ion based on coumarin dye and malononitrile (180, figure 59 ). the fluorescence response of probe 180 at 459 nm towards hypochlorite ions gradually enhanced with the increase of clo − concentrations, resulting in 45-fold fluorescence enhancement. furthermore, probe 180 exhibited high accuracy for quantitative measurement of hypochlorite ions in real water samples and it can be used as a potential chemosensor for the detection of clo − in chemical environmental and biological systems [238] . in the same year, tang and co-workers worked on a coumarin based fluorescent probe (181, figure 59 ) able of rapidly discern hypochlorite and copper(ii) ions in water sample and biological systems. upon the reaction with clo − , the fluorescence wavelength of 181 displayed a strong blue shift along with the naked-eye visible changes from yellow to colorless. moreover, it exhibited an obvious fluorescence quenching behavior to copper(ii) with colorimetric analysis from yellow to luminous yellow [239] . because of the presence of the 7-diethylamino group and the 3-substituted lactone ring that are wellknown structural pattern accountable for the fluorescence properties. it was observed a different reactivity profile depending on the ph levels, probably due to the different reactivity of hypochlorite ions ascribable to the variation of the dissociation of the salt at different ph values. afterwards, a deeply investigation on the possible formation of chlorinated derivatives was conducted: hplc-pda-esi-ms analyses highlighted the presence of chlorinated derivatives and proved that the chlorination reaction was responsible for the linear fluorescence decays. the results suggest the possibility to exploit these coumarin ionic probes for the detection and quantitative determination of hypochlorite species in vivo. a coumarin fluorescent probe based on a nitro-3-carboxamide derivative for selective copper (ii) ions detection was reported by bekhradnia and colleagues. compound 185 (figure 60 ) showed the highest fluorescence intensity in presence of cu 2+ compared to a variety of other common heavy and toxic metal ions (for example pb(ii), co(ii), hg(ii)) and in aqueous solution at 320 nm [241] . another approach was attempted for the selective detection of copper (ii) ions by he et al. in 2018, which based the fluorescent probe on a coumarin-schiff base derivative (186, figure 60 ). this probe resulted to be particularly selective for cu 2+ even in the presence of several other ions [242] . saravana a noteworthy research on the mechanism of interaction between coumarin based ionic probes and hypochlorite ions had been conducted by starzak and collaborators [240] . first, the research team confirmed the linear decrease in the fluorescence emissions together with the increase in clo − concentration of three different coumarin derivatives, 182-184 (figure 59 ), which were selected because of the presence of the 7-diethylamino group and the 3-substituted lactone ring that are well-known structural pattern accountable for the fluorescence properties. it was observed a different reactivity profile depending on the ph levels, probably due to the different reactivity of hypochlorite ions ascribable to the variation of the dissociation of the salt at different ph values. afterwards, a deeply investigation on the possible formation of chlorinated derivatives was conducted: hplc-pda-esi-ms analyses highlighted the presence of chlorinated derivatives and proved that the chlorination reaction was responsible for the linear fluorescence decays. the results suggest the possibility to exploit these coumarin ionic probes for the detection and quantitative determination of hypochlorite species in vivo. a coumarin fluorescent probe based on a nitro-3-carboxamide derivative for selective copper (ii) ions detection was reported by bekhradnia and colleagues. compound 185 ( figure 60 ) showed the highest fluorescence intensity in presence of cu 2+ compared to a variety of other common heavy and toxic metal ions (for example pb(ii), co(ii), hg(ii)) and in aqueous solution at 320 nm [241] . another approach was attempted for the selective detection of copper (ii) ions by he et al. in 2018, which based the fluorescent probe on a coumarin-schiff base derivative (186, figure 60 ). this probe resulted to be particularly selective for cu 2+ even in the presence of several other ions [242] . saravana mani and colleagues designed in 2019 a coumarin hydrazine-based fluorescent probe for the detection of copper(ii), called benzepyr (187, figure 60 ), exploiting a reaction of condensation between 2-hydrazino benzothiazole and n,n -diethylamino-3-acetyl coumarin [243] . this particular fluorescent chemosensor could selectively detect cu 2+ among other disturbing metal ions, resulting particularly specific and highly responsive, with a visible colorimetric change of the solution, which turned from yellow to wine red. moreover, the limit of detection (lod) had been estimated to be 40 nm. benzepyr 187 was also tested for the fluorescence bioimaging of cu 2+ ions in hela cells using fluorescence microscopic analysis, resulting suitable for the exploitation as an ion marker in living cells. but also al ions and amino acids lys and arg [244] . in particular, the detection of lys and arg took place with a colorimetric (from yellow to colorless) and a fluorescent response (from a maximum absorption at 335 nm to 429 nm). at the same time the probe detected either way the presence of cu 2+ ions but could be used only for the fluorescent sensing of al 3+ . a further interesting exploitation of probe 188 (figure 60 ) was the fluorescent and colorimetric identification of cys, hcy and gsh when it was complexed with copper ions. despite the key role of chemical species like copper and hypochlorite, they are not the only ions valuable for detection. for this reason, a dual coumarin probe, fluorescent and colorimetric, was designed by chen and colleagues for the detection of palladium (ii) ions that can be used in living cells. this oxime-ether coumarin probe (189, figure 61 ) exhibited a strong green fluorescence with an emission peak at 500 nm. when palladium(ii) was added to the solution with compound 189, the fluorescence intensity at 500 nm decreased consequently, until 2 equivalents of pd 2+ were reached; at that point the fluorescence was almost completely quenched, which could clearly be observed with the naked eye. a linear fit between fluorescence and palladium (ii) concentration was observed in the range 0.0-8.0 μm, while the detection limit was measured to be 40 nm, which is far lower than the threshold for palladium content in drugs (5.0 ppm to 10.0 ppm -47.0 mm to 94.0 mm) specified by the world health organization [245] . it is also noteworthy the development of thioacetalised coumarin based fluorescent probes for the detection of mercury (ii), a hazardous ion both for human health and reproduction. cheng and co-workers exploited the known hg 2+ promoted deprotection reaction of dithioacetals to design two novel reactive fluorescent probes (190,191, figure 61 ) that showed a different behavior due to the different chemical structures: 190 displayed remarkable fluorescence quenching with the addition of another remarkable case of coumarin-based chemosensor had been presented by li and co-workers, who synthesized a multifunctional probe able to selectively detect not only copper (ii) ions but also al 3+ ions and amino acids lys and arg [244] . in particular, the detection of lys and arg took place with a colorimetric (from yellow to colorless) and a fluorescent response (from a maximum absorption at 335 nm to 429 nm). at the same time the probe detected either way the presence of cu 2+ ions but could be used only for the fluorescent sensing of al 3+ . a further interesting exploitation of probe 188 (figure 60 ) was the fluorescent and colorimetric identification of cys, hcy and gsh when it was complexed with copper ions. despite the key role of chemical species like copper and hypochlorite, they are not the only ions valuable for detection. for this reason, a dual coumarin probe, fluorescent and colorimetric, was designed by chen and colleagues for the detection of palladium (ii) ions that can be used in living cells. this oxime-ether coumarin probe (189, figure 61 ) exhibited a strong green fluorescence with an emission peak at 500 nm. when palladium(ii) was added to the solution with compound 189, the fluorescence intensity at 500 nm decreased consequently, until 2 equivalents of pd 2+ were reached; at that point the fluorescence was almost completely quenched, which could clearly be observed with the naked eye. a linear fit between fluorescence and palladium (ii) concentration was observed in the range 0.0-8.0 µm, while the detection limit was measured to be 40 nm, which is far lower than the threshold for palladium content in drugs (5.0 ppm to 10.0 ppm -47.0 mm to 94.0 mm) specified by the world health organization [245] . it is also noteworthy the development of thioacetalised coumarin based fluorescent probes for the detection of mercury (ii), a hazardous ion both for human health and reproduction. cheng and co-workers exploited the known hg 2+ promoted deprotection reaction of dithioacetals to design two novel reactive fluorescent probes (190, 191, figure 61 ) that showed a different behavior due to the different chemical structures: 190 displayed remarkable fluorescence quenching with the addition of hg 2+ ions while, in the presence of mercury ions, 191 displayed ratiometric fluorogenic and chromogenic response [246] . it should not be forgotten an on-off fluorescent probe for the tracking of iron (iii) ions based on 7-hydroxy-2-oxo-n-(pyridin-2-ylmethyl)chromene-3-carboxamide. in their work, warrier and kharkar demonstrated that compound 192 (figure 61 ) was selective towards fe 3+ ions and exhibited high fluorescence emission profile at 447 nm. the presence of other ions did not interfere with the detection of iron (iii) ions and the limit of detection was found to be 0.76 µm. moreover, cell imaging and mtt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay proved the potential utility of probe 192 as cell-permeable chemosensor of fe 3+ in living cells [247] . the approach of jiao and colleagues for the detection of fluoride ions was based on the linkage between the coumarin scaffold and fluorescein in order to obtain a highly selective and sensitive fluorescent probe. the mechanism of f − ions detection by compound 193 (figure 61 ) was explained and involved a desilylation reaction in the presence of fluoride ions. moreover, a linear relationship between the ratio of emission intensities at 532 and 465 nm and f − concentration over the range of 0-20 µm with a limit of detection of 0.025 µm was found [248] . differently, yao and co-workers exploited the capability of fluoride ions to form stable complex with ca 2+ to design a novel fluorescent sensor (194, figure 61) , synthesized from the combination of mandelic acid with 7-hydroxy-8-formylcoumarin through a hydrazine hydrate bridge, in order to selectively identify these two ionic species over other metal ions [249] . the fluorescence spectrum of compound 194 clearly increased when calcium ions were added to the solution with a limit of detection of 5.81 × 10 −7 m, while, once the complex between the probe and ca 2+ ions was obtained, the addition of fluoride ions to the solution lead to the turn-off of the fluorescence response with a limit of detection 4.28 × 10 −7 m. moreover, bio-imaging studies were performed in order to assure the possibility to exploit this novel chemosensor for the identification of ca 2+ and f − ions in vivo, with positive outcome. finally, reddy and choi designed and synthesized three dicyanovinylcoumarin probes as turn-on fluorescent sensor for the detection of cn − ions among other anions [250] . within the different synthesized probes only compound 195 ( figure 61 ) showed a remarkable increase of the fluorescence in presence of fluoride and cyanide ions with an interesting sensibility towards cn − ions: the limit of detection was up to 11.4 nm, lower than the maximum level in drinkable water according to who guidelines. high fluorescence emission profile at 447 nm. the presence of other ions did not interfere with the detection of iron (iii) ions and the limit of detection was found to be 0.76 μm. moreover, cell imaging and mtt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay proved the potential utility of probe 192 as cell-permeable chemosensor of fe 3+ in living cells [247] . the approach of jiao and colleagues for the detection of fluoride ions was based on the linkage between the coumarin scaffold and fluorescein in order to obtain a highly selective and sensitive fluorescent probe. the mechanism of fions detection by compound 193 (figure 61 ) was explained and involved a desilylation reaction in the presence of fluoride ions. moreover, a linear relationship between the ratio of emission intensities at 532 and 465 nm and f − concentration over the range of 0-20 μμ with a limit of detection of 0.025 μμ was found [248] . differently, yao and co-workers exploited the capability of fluoride ions to form stable complex with ca 2+ to design a novel fluorescent sensor (194, figure 61) , synthesized from the combination of mandelic acid with 7-hydroxy-8formylcoumarin through a hydrazine hydrate bridge, in order to selectively identify these two ionic species over other metal ions [249] . the fluorescence spectrum of compound 194 clearly increased when calcium ions were added to the solution with a limit of detection of 5.81 × 10 -7 m, while, once the complex between the probe and ca 2+ ions was obtained, the addition of fluoride ions to the solution lead to the turn-off of the fluorescence response with a limit of detection 4.28 × 10 -7 m. moreover, bio-imaging studies were performed in order to assure the possibility to exploit this novel chemosensor for the identification of ca 2+ and fions in vivo, with positive outcome. finally, reddy and choi designed and synthesized three dicyanovinylcoumarin probes as turnon fluorescent sensor for the detection of cnions among other anions [250] . within the different synthesized probes only compound 195 ( figure 61 ) showed a remarkable increase of the fluorescence in presence of fluoride and cyanide ions with an interesting sensibility towards cnions: the limit of detection was up to 11.4 nm, lower than the maximum level in drinkable water according to who guidelines. coumarins have found important applications also in the agri-food sector. in fact, the antimicrobial activity characterizing these natural compounds could be exploited for food coumarins have found important applications also in the agri-food sector. in fact, the antimicrobial activity characterizing these natural compounds could be exploited for food preservation or for the treatment of plant pathogens, infections in aquaculture or biofouling caused by eukaryotic organisms. in addition, because coumarin scaffold has been used in fluorescent probing, natural coumarins might be used in the detection of some substances in food samples. for instance, zhang and collaborators developed a new near-infrared probe constituted by a conjugated coumarin-indolium system, for rapid, colorimetric and ratiometric fluorescent detection of bisulfite and sulfite anions [251] . (bi)sulfite anions (hso 3 − /so 3 2− ) are widely used as preservative for foods and beverages in order to prevent oxidation, browning and microbial reaction during products' life cycle [252, 253] . unfortunately, high doses of (bi)sulfites can cause asthma or other allergic reactions. some individuals are very sensitive even to low levels of these anions [254] . in addition, sulfur dioxide (so 2 ) is one of the most distributed pollutants and it has a relevant impact on human health [252] , [253, 255] . an efficient tool to detect such molecules is provided by fluorescent probes; to date, different probes for hso 3 − /so 3 2− have been designed but many of them are intensity-based, which means that the signal output can be conditioned by different factors such as instrumental efficiency, probe concentration, environmental conditions. in addition, many of these probes show emissions only in the visible region and some of them need ultraviolet excitation, having limited biological applications. thus, new, more efficient probes are required. in zhang's work, a conjugated coumarin-indolium system with intramolecular charge transfer (ict) effect was developed, merging an electron-donating 7-diethylamino coumarin moiety and an electron-withdrawing positively charged indolium derivative, connected through an ethylene linker (figure 62 ). the whole system resulted in a typical 'push-pull' large conjugation dye system with ict properties. the so-designed probe showed nir fluorescence (667 nm) and a rapid, highly selective and sensitive detection process for hso 3 − /so 3 2− in aqueous solution under mild conditions; in addition, this probe exhibited significant colorimetric, nir fluorescent and ratiometric signal responses upon one excitation wave and a detection lower limit of ∼27 nm. this probe can be applied to detect hso 3 − /so 3 2− in real food samples, serum samples and living cells. when tested on real food samples (sugar, soft sugar, crystal sugar and wine in aqueous solution) this probe proved to be able to determine hso 3 − with good recovery. in addition, a paper test strip was developed, simply by wetting a strip of neutral filter paper with a solution of the probe in methanol (200 µm figure 62 ) can be used to develop a cheap, easy-to-prepare and easy-to-use paper test strip system for the detection of (bi)sulfites. and sulfite anions [251] . (bi)sulfite anions (hso3 − /so3 2− ) are widely used as preservative for foods and beverages in order to prevent oxidation, browning and microbial reaction during products' life cycle [252, 253] . unfortunately, high doses of (bi)sulfites can cause asthma or other allergic reactions. some individuals are very sensitive even to low levels of these anions [254] . in addition, sulfur dioxide (so2) is one of the most distributed pollutants and it has a relevant impact on human health [252] , [253, 255] . an efficient tool to detect such molecules is provided by fluorescent probes; to date, different probes for hso3 − /so3 2− have been designed but many of them are intensity-based, which means that the signal output can be conditioned by different factors such as instrumental efficiency, probe concentration, environmental conditions. in addition, many of these probes show emissions only in the visible region and some of them need ultraviolet excitation, having limited biological applications. thus, new, more efficient probes are required. in zhang's work, a conjugated coumarinindolium system with intramolecular charge transfer (ict) effect was developed, merging an electron-donating 7-diethylamino coumarin moiety and an electron-withdrawing positively charged indolium derivative, connected through an ethylene linker ( figure 62 ). the whole system resulted in a typical 'push-pull' large conjugation dye system with ict properties. the so-designed probe showed nir fluorescence (667 nm) and a rapid, highly selective and sensitive detection process for hso3 − /so3 2-in aqueous solution under mild conditions; in addition, this probe exhibited significant colorimetric, nir fluorescent and ratiometric signal responses upon one excitation wave and a detection lower limit of ∼27 nm. this probe can be applied to detect hso3 − /so3 2-in real food samples, serum samples and living cells. when tested on real food samples (sugar, soft sugar, crystal sugar and wine in aqueous solution) this probe proved to be able to determine hso3 -with good recovery. in addition, a paper test strip was developed, simply by wetting a strip of neutral filter paper with a solution of the probe in methanol (200 μm) . the result was a deep blue test paper ready for use: when a hso3 − solution is spotted on the test paper, rapid color changes can be observed, even if many other ions are present in the sample. different colors correspond to different concentrations of hso3 − . thus, probe 196 ( figure 62 ) can be used to develop a cheap, easy-to-prepare and easy-to-use paper test strip system for the detection of (bi)sulfites. a more recent example is a probe developed by nair and collaborators, able to selectively detect the amphiphilic bisulfate ion (hso4 − ) in edible plant foods, dog urine and drugs [256] . bisulfate consumption normally takes place through the ingestion of different edible plants, such as cabbage, broccoli, brussels sprouts, horseradish or seeds (black and white mustard, for instance). these plants contain glucosinolates [257, 258] that are hydrolyzed in our organism by the enzyme myrosinase, thus producing bisulfate ion [259] . in addition, bisulfate salts of many apis are currently on market, constituting another source of bisulfate ions [260] . when trying to evaluate the actual concentration of hso4 − , it is important to take account of the deprotonation equilibrium between hso4 − and so4 2-, a more recent example is a probe developed by nair and collaborators, able to selectively detect the amphiphilic bisulfate ion (hso 4 − ) in edible plant foods, dog urine and drugs [256] . bisulfate consumption normally takes place through the ingestion of different edible plants, such as cabbage, broccoli, brussels sprouts, horseradish or seeds (black and white mustard, for instance). these plants contain glucosinolates [257, 258] that are hydrolyzed in our organism by the enzyme myrosinase, thus producing bisulfate ion [259] . in addition, bisulfate salts of many apis are currently on market, constituting another source of bisulfate ions [260] . when trying to evaluate the actual concentration of hso 4 − , it is important to take account of the deprotonation equilibrium between hso 4 − and so 4 2− , using a highly selective probe able to discriminate between these two ions. nair and co-workers developed two fully water-soluble probes, coumarin-integrated glycine (cg) and coumarin-integrated alanine (ca) zwitterions, for the selective detection of hso 4 − at picomolar level (from 50 to 325 pm) ( figure 63 ). int. j. mol. sci. 2020, 21, x for peer review 41 of 83 using a highly selective probe able to discriminate between these two ions. nair and co-workers developed two fully water-soluble probes, coumarin-integrated glycine (cg) and coumarinintegrated alanine (ca) zwitterions, for the selective detection of hso4 − at picomolar level (from 50 to 325 pm) ( figure 63 ). glycine and alanine can interact selectively with the target through h-bond, due to their zwitterionic nature at physiological ph, whereas the 7-hydroxycoumarin moiety constitutes a good fluorophore probe, thanks to its biocompatibility, non-toxicity and water solubility. the cg/ca probes proved to be able to penetrate and stain living cell. when different unknown concentrations of clopidogrel bisulfate were added to a water solution of cg/ca, it was possible to precisely measure such concentration by measuring the emission intensity of each sample. confirmation of the experimentally observed values with the theoretically calculated ones supported the accuracy of the presented method. cg/ca probes were also tested on food samples: water extracts of cruciferous plant foods (cabbage, broccoli, mustard seeds, carrots) were added to aqueous solutions of the probes. again, titration of bisulfate ions was performed by emission measurements-addition of increasing volumes of aqueous food saps caused a growing reduction of probe's emission. cucumber and fenugreek were used as controls, as they do not contain bisulfates. eventually, bisulfate content was measured in pet urine samples (bisulfate is one of the common components of pet foods): urine samples were collected from two adult dogs and were treated with aqueous solution of cg/ca; a reduction of probe emission was noticed, revealing the presence of hso4 − (quenching was proportional to bisulfate quantity). in conclusion, cg and ca probes demonstrated the ability to detect bisulfate ions in aqueous solution at ph = 7.4, wherein hso4 − concentration was 10 5.4 lower than that of so4 2-, at concentration as low as 50 pm, even in presence of other ions. with regards to the antimicrobial activity of coumarin scaffold, some studies have been recently carried out, showing the potential of natural coumarins as food preservatives. yang and co-workers have studied the antimicrobial activity of eighteen natural compounds against r. solanacearum [261] , a bacterium responsible for the wilting of different plants such as tobacco, tomato, potato in (sub)tropical regions, causing significant economic losses [262, 263] . among them, four coumarins ( figure 64 ) showed an antibacterial activity stronger than that of thiodiazole copper treatment (antibacterial rate (mbc/mic) of 63.3%). daphnetin showed the highest activity, followed by xanthotol and esculetin (antibacterial rate 97.43%, 80.12% and 71.44%, respectively). antibacterial activity seemed to be enhanced by c6, c7 or c8 substitution, so hydroxycoumarins umbelliferone, esculetin and daphnetin were selected for further investigation of the mechanism of action. hydroxycoumarins were tested from 10 to 100 mg/l concentrations and from results it was clear that the good activity of umbelliferone can be enhanced by the additional hydroxylation of c6 position (esculetin), whereas even better results can be achieved by the dihydroxylation of c7 and c8 positions (daphnetin). tem images of r. solanacearum showed that daphnetin and esculetin caused irreversible damages to the cell membrane, whereas umbelliferone must follow a different path in inducing cell damage. it is worth noting that hydroxycoumarins showed very low cytotoxicity on human cells and have no effects on tobacco seeds' germination. furthermore, because r. solanacearum forms biofilm-like aggregations on host's roots, facilitating bacterial infection [264] , yang and his group speculated that hydroxycoumarins may interfere with biofilm formation. in fact, daphnetin, umbelliferone and esculetin (100 mg/l) reduced biofilm formation by 99.22%, 85.20% and 93.90%, respectively, probably influencing the swimming motility of the bacterium. thus, the glycine and alanine can interact selectively with the target through h-bond, due to their zwitterionic nature at physiological ph, whereas the 7-hydroxycoumarin moiety constitutes a good fluorophore probe, thanks to its biocompatibility, non-toxicity and water solubility. the cg/ca probes proved to be able to penetrate and stain living cell. when different unknown concentrations of clopidogrel bisulfate were added to a water solution of cg/ca, it was possible to precisely measure such concentration by measuring the emission intensity of each sample. confirmation of the experimentally observed values with the theoretically calculated ones supported the accuracy of the presented method. cg/ca probes were also tested on food samples: water extracts of cruciferous plant foods (cabbage, broccoli, mustard seeds, carrots) were added to aqueous solutions of the probes. again, titration of bisulfate ions was performed by emission measurements-addition of increasing volumes of aqueous food saps caused a growing reduction of probe's emission. cucumber and fenugreek were used as controls, as they do not contain bisulfates. eventually, bisulfate content was measured in pet urine samples (bisulfate is one of the common components of pet foods): urine samples were collected from two adult dogs and were treated with aqueous solution of cg/ca; a reduction of probe emission was noticed, revealing the presence of hso 4 − (quenching was proportional to bisulfate quantity). in [262, 263] . among them, four coumarins ( figure 64 ) showed an antibacterial activity stronger than that of thiodiazole copper treatment (antibacterial rate (mbc/mic) of 63.3%). daphnetin showed the highest activity, followed by xanthotol and esculetin (antibacterial rate 97.43%, 80.12% and 71.44%, respectively). antibacterial activity seemed to be enhanced by c6, c7 or c8 substitution, so hydroxycoumarins umbelliferone, esculetin and daphnetin were selected for further investigation of the mechanism of action. hydroxycoumarins were tested from 10 to 100 mg/l concentrations and from results it was clear that the good activity of umbelliferone can be enhanced by the additional hydroxylation of c6 position (esculetin), whereas even better results can be achieved by the dihydroxylation of c7 and c8 positions (daphnetin). tem images of r. solanacearum showed that daphnetin and esculetin caused irreversible damages to the cell membrane, whereas umbelliferone must follow a different path in inducing cell damage. it is worth noting that hydroxycoumarins showed very low cytotoxicity on human cells and have no effects on tobacco seeds' germination. furthermore, because r. solanacearum forms biofilm-like aggregations on host's roots, facilitating bacterial infection [264] , yang and his group speculated that hydroxycoumarins may interfere with biofilm formation. in fact, daphnetin, umbelliferone and esculetin (100 mg/l) reduced biofilm formation by 99.22%, 85.20% and 93.90%, respectively, probably influencing the swimming motility of the bacterium. thus, the expression of the regulating and structural flagellar genes flia, flhc and flhd in presence of daphnetin, umbelliferone and esculetin was evaluated and it turned out that the expression of flia and flhc was significantly repressed by the mentioned compounds. expression of the regulating and structural flagellar genes flia, flhc and flhd in presence of daphnetin, umbelliferone and esculetin was evaluated and it turned out that the expression of flia and flhc was significantly repressed by the mentioned compounds. another interesting biological activity ascribed to the coumarin nucleus is its antifungal activity, which can be useful not only in the medicinal field but also in the agricultural one. as far as the latter is concerned, there has been an increasing interest in the exploitation of coumarin scaffold for the design and synthesis of novel fungicides useful in the treatment of many plant diseases. many pathogenic fungi still cause massive death of crops, limiting production and causing significant financial losses. to date, farmers deal with this problem by using chemical fungicides but such solution comes with some drawbacks: the long and extensive use of these chemicals may cause environmental pollution, accumulation of pesticides residues in the plants and drug resistance by fungi. thus, there is an urgent need for alternative (and green) solutions. in 2019, ramìrez-pelayo and his collaborators studied the coumarin-based compounds contained in the peel of citrus grown in colombia [265] . six coumarins were isolated (197-202, figure 65 ) and their antifungal activity, in terms of mycelial growth and spore germination inhibition, was evaluated against the fungus causing anthracnose (colletotrichum sp.). the production of oranges, mandarins, grapefruit, lemons, limes is limited by the action of microorganisms able to proliferate in such fruits because of peculiar condition such as high nutrient content, humidity and low ph values. nevertheless, these plants can defend themselves from pathogens thanks to the production of antimicrobial compounds which can be constitutive (phytoanticipins) or induced (phytoalexins) [266, 267] . another interesting biological activity ascribed to the coumarin nucleus is its antifungal activity, which can be useful not only in the medicinal field but also in the agricultural one. as far as the latter is concerned, there has been an increasing interest in the exploitation of coumarin scaffold for the design and synthesis of novel fungicides useful in the treatment of many plant diseases. many pathogenic fungi still cause massive death of crops, limiting production and causing significant financial losses. to date, farmers deal with this problem by using chemical fungicides but such solution comes with some drawbacks: the long and extensive use of these chemicals may cause environmental pollution, accumulation of pesticides residues in the plants and drug resistance by fungi. thus, there is an urgent need for alternative (and green) solutions. in 2019, ramìrez-pelayo and his collaborators studied the coumarin-based compounds contained in the peel of citrus grown in colombia [265] . six coumarins were isolated (197-202, figure 65 ) and their antifungal activity, in terms of mycelial growth and spore germination inhibition, was evaluated against the fungus causing anthracnose (colletotrichum sp.). the production of oranges, mandarins, grapefruit, lemons, limes is limited by the action of microorganisms able to proliferate in such fruits because of peculiar condition such as high nutrient content, humidity and low ph values. nevertheless, these plants can defend themselves from pathogens thanks to the production of antimicrobial compounds which can be constitutive (phytoanticipins) or induced (phytoalexins) [266, 267] . another interesting biological activity ascribed to the coumarin nucleus is its antifungal activity, which can be useful not only in the medicinal field but also in the agricultural one. as far as the latter is concerned, there has been an increasing interest in the exploitation of coumarin scaffold for the design and synthesis of novel fungicides useful in the treatment of many plant diseases. many pathogenic fungi still cause massive death of crops, limiting production and causing significant financial losses. to date, farmers deal with this problem by using chemical fungicides but such solution comes with some drawbacks: the long and extensive use of these chemicals may cause environmental pollution, accumulation of pesticides residues in the plants and drug resistance by fungi. thus, there is an urgent need for alternative (and green) solutions. in 2019, ramìrez-pelayo and his collaborators studied the coumarin-based compounds contained in the peel of citrus grown in colombia [265] . six coumarins were isolated (197-202, figure 65 ) and their antifungal activity, in terms of mycelial growth and spore germination inhibition, was evaluated against the fungus causing anthracnose (colletotrichum sp.). the production of oranges, mandarins, grapefruit, lemons, limes is limited by the action of microorganisms able to proliferate in such fruits because of peculiar condition such as high nutrient content, humidity and low ph values. nevertheless, these plants can defend themselves from pathogens thanks to the production of antimicrobial compounds which can be constitutive (phytoanticipins) or induced (phytoalexins) [266, 267] . as already mentioned, from the methanol extracts of c. latifolia and c. aurantifolia peels six compounds were isolated-5-geranyloxy-7-methoxycoumarin (197) , bergamottin (198) , bergapten (199) , isopimpinellin (200) , limettin (201) and oxypeucedanin hydrate (202) and their activity was compared to that of umbelliferone, scoparone and scopoletin. compounds 197-201 were tested at 0.25, 0.50 and 1.00 mm, whereas 202 was tested at 1.00 mm concentration. carbendazin and thymol were used as reference compounds (0.5 mm). the results showed that compounds 197-202 significantly inhibited mycelial growth of colletotrichum sp., the activity being proportional to the dose used. the (201)) was investigated, each of them showing enhanced activity respect to both the individual compounds. furthermore, the activity of 199, 201 and their mixtures was compared to that of the phytolaxins scoparone, scopoletin and umbelliferone; the results showed that phytolaxins were just slightly more active than the isolated compounds, although the highest fungistatic activity was shown by the mixture of 201 (0.75 mm) and 199 (0.25 mm). this mixture, along with compounds 197, 199 and 201, was selected for the evaluation of the inhibitory effect on spore germination in comparison with scopoletin, scoparone and umbelliferone. compounds 201 and 199 exhibited very good activity, with 96.7% and 95.3% inhibition, respectively but these percentages rapidly decrease, being less than 5% after 24 h. again, the 199/201 mixture showed the highest activity causing a complete, long-lasting inhibition of spore germination, thus suggesting that there may be an additive or synergistic effect between these compounds. therefore, coumarins and furanocoumarins may be useful scaffolds in the design of new antifungal agents. in 2018, yu and co-workers designed a series of coumarin-3-carboxamide derivatives and evaluated their antifungal activity against botrytis cinerea, alternaria solani, gibberella zeae, rhizoctonia solani, cucumber anthrax and alternaria leaf spot [268] . these phytopathogenic fungi are all relevant in agriculture, because they can cause significant losses in crops and investments. in this work, two different scaffolds were merged in order to design a new category of more effective fungicides. in fact, the use of carboxylic acid amides (caa) in this context is well-established, because amide fungicides have been used for over 50 years [269] . more recently, new amide fungicides with high activity and broad spectrum of action were developed (e.g., fluopyram, bixafen, sedaxane, isopyrazam, penthiopirad and boscalid) [1, 270] . in addition, hydrazide scaffolds have been found to have interesting biological and pharmacological activities [271, 272] . similarly, the antifungal activity of coumarin nucleus is well known (paragraph 0). considering these elements, the authors decided to combine the coumarin and the carboxamide/hydrazide scaffolds with the aim of synthesizing high-performance fungicides. all the synthesized compounds were tested and their antifungal activities against the mentioned phytopathogenic fungi were evaluated. at 100 µg/ml concentration, most of the tested compounds showed poor antifungal activity. only compounds 203 and 204 ( figure 66 ) showed ec 50 values of 1.57 µg/ml and 1.65 µg/ml, respectively, against botrytis cinerea, proving to be equivalent to the reference boscalid (0.51 µg/ml), whereas 203 (ec 50 = 1.80 µg/ml) resulted more active than boscalid (ec 50 = 2.98 µg/ml) against rhizoctonia solani. as already mentioned, from the methanol extracts of c. latifolia and c. aurantifolia peels six compounds were isolated-5-geranyloxy-7-methoxycoumarin (197) , bergamottin (198) , bergapten (199) , isopimpinellin (200) , limettin (201) and oxypeucedanin hydrate (202) and their activity was compared to that of umbelliferone, scoparone and scopoletin. compounds 197-201 were tested at 0.25, 0.50 and 1.00 mm, whereas 202 was tested at 1.00 mm concentration. carbendazin and thymol were used as reference compounds (0.5 mm). the results showed that compounds 197-202 significantly inhibited mycelial growth of colletotrichum sp., the activity being proportional to the dose used. the highest inhibition was exhibited by compounds 199 and 201 (32% and 25%, respectively); therefore, the fungistatic (201)) was investigated, each of them showing enhanced activity respect to both the individual compounds. furthermore, the activity of 199, 201 and their mixtures was compared to that of the phytolaxins scoparone, scopoletin and umbelliferone; the results showed that phytolaxins were just slightly more active than the isolated compounds, although the highest fungistatic activity was shown by the mixture of 201 (0.75 mm) and 199 (0.25 mm). this mixture, along with compounds 197, 199 and 201, was selected for the evaluation of the inhibitory effect on spore germination in comparison with scopoletin, scoparone and umbelliferone. compounds 201 and 199 exhibited very good activity, with 96.7% and 95.3% inhibition, respectively but these percentages rapidly decrease, being less than 5% after 24 hours. again, the 199/201 mixture showed the highest activity causing a complete, long-lasting inhibition of spore germination, thus suggesting that there may be an additive or synergistic effect between these compounds. therefore, coumarins and furanocoumarins may be useful scaffolds in the design of new antifungal agents. in 2018, yu and co-workers designed a series of coumarin-3-carboxamide derivatives and evaluated their antifungal activity against botrytis cinerea, alternaria solani, gibberella zeae, rhizoctonia solani, cucumber anthrax and alternaria leaf spot [268] . these phytopathogenic fungi are all relevant in agriculture, because they can cause significant losses in crops and investments. in this work, two different scaffolds were merged in order to design a new category of more effective fungicides. in fact, the use of carboxylic acid amides (caa) in this context is well-established, because amide fungicides have been used for over 50 years [269] . more recently, new amide fungicides with high activity and broad spectrum of action were developed (e.g., fluopyram, bixafen, sedaxane, isopyrazam, penthiopirad and boscalid) [1, 270] . in addition, hydrazide scaffolds have been found to have interesting biological and pharmacological activities [271, 272] . similarly, the antifungal activity of coumarin nucleus is well known (paragraph 0). considering these elements, the authors decided to combine the coumarin and the carboxamide/hydrazide scaffolds with the aim of synthesizing highperformance fungicides. all the synthesized compounds were tested and their antifungal activities against the mentioned phytopathogenic fungi were evaluated. at 100 μg/ml concentration, most of the tested compounds showed poor antifungal activity. only compounds 203 and 204 ( figure 66 ) showed ec50 values of 1.57 μg/ml and 1.65 μg/ml, respectively, against botrytis cinerea, proving to be equivalent to the reference boscalid (0.51 μg/ml), whereas 203 (ec50 = 1.80 μg/ml) resulted more active than boscalid (ec50 = 2.98 μg/ml) against rhizoctonia solani. starting from these data it was possible to suggest some structure-activity relationships: the replacement of amide bond with a hydrazide bond led to an improvement in antifungal activity spectrum. furthermore, coumarins bearing amide group resulted to be remarkably more active against botrytis cinerea and rhizoctonia solani, whereas against alternaria solani, gibberella zeae, starting from these data it was possible to suggest some structure-activity relationships: the replacement of amide bond with a hydrazide bond led to an improvement in antifungal activity spectrum. furthermore, coumarins bearing amide group resulted to be remarkably more active against botrytis cinerea and rhizoctonia solani, whereas against alternaria solani, gibberella zeae, cucumber anthrax and alternaria leaf spot they showed less potency. it is noteworthy that compounds bearing an electron-withdrawing group did not show any activity, whereas compounds with an electro-donating group were active against alternaria leaf spot. the addition to the coumarin nucleus of cl/f-substituted phenylidrazine gave compounds active on cucumber anthrax. a similar approach is the one followed by yang and collaborators, who decided to exploit coumarin nucleus for the functionalization of chitosan, in order to create more effective chitosan-based fungicides [273] . in fact, chitosan is becoming more and more appreciated due to its antimicrobial activity, low toxicity, biodegradability, biocompatibility and film forming activity. however, its application as fungicide is limited by its low solubility and weaker activity respect to the on-market fungicides. in this work, four coumarin-functionalized chitosan derivatives (205a-d, figure 67 ), were synthesized and tested against the phytopathogens alternaria solani sorauer, fusarium oxysporum f.sp. vasinfectum and fusarium moniliforme by evaluating the mycelial growth rate in vitro. at 1.0 mg/ml, compounds 205a-d showed inhibitory activity against a. solani, following the sequence 205d > 205b > 205c > 205a (38.25%, 51.23%, 44.01% and 52, 78%, respectively). cucumber anthrax and alternaria leaf spot they showed less potency. it is noteworthy that compounds bearing an electron-withdrawing group did not show any activity, whereas compounds with an electro-donating group were active against alternaria leaf spot. the addition to the coumarin nucleus of cl/f-substituted phenylidrazine gave compounds active on cucumber anthrax. a similar approach is the one followed by yang and collaborators, who decided to exploit coumarin nucleus for the functionalization of chitosan, in order to create more effective chitosan-based fungicides [273] . in fact, chitosan is becoming more and more appreciated due to its antimicrobial activity, low toxicity, biodegradability, biocompatibility and film forming activity. however, its application as fungicide is limited by its low solubility and weaker activity respect to the on-market fungicides. in this work, four coumarin-functionalized chitosan derivatives (205a-d, figure 67 ), were synthesized and tested against the phytopathogens alternaria solani sorauer, fusarium oxysporum f.sp. vasinfectum and fusarium moniliforme by evaluating the mycelial growth rate in vitro. at 1.0 mg/ml, compounds 205ad showed inhibitory activity against a. solani, following the sequence 205d > 205b > 205c > 205a (38.25%, 51.23%, 44.01% and 52, 78%, respectively). these results suggested that the introduction of halogens caused an increase in activity, depending on the number and the type of halogens. for instance, the 3,5-dichloro derivatives were more active against a. solani than the correspondent 5-cl or 5-br derivatives, probably because of an increase of hydrophobicity. the four coumarin-chitosan derivatives showed higher activity than chitosan alone also against f. oxysporum and f. moniliforme. compound 205d showed an inhibitory index of 57.09% against a. solani, 77.24% against f. oxysporum and 66.12% against f. moniliforme. the great biological potential of coumarins might be even increased by considering the possibility to complex coumarin scaffold with other substances as, for example, some metals. in fact, it has been proved that it is possible to enhance the activity of a certain drug simply binding it to a metallic-element [274] ; moreover, by combining known active moieties with metals, it would be possible to improve the parent compound with a certain selectivity or even with a new mechanism of action. therefore, many groups have already started to explore this strategy, aiming to produce more active compounds, exploiting metals as copper, platinum, zinc or silver. in some cases, due to its intrinsic potential, coumarin scaffold was exploited in this approach. some examples are discussed below. the nature of coumarin-copper complexes had already been evaluated in 2001 by karaliota and co-workers, who synthesized and characterized a binuclear coumarin-3-carboxilate-copper (ii) complex (206) [275] . in this work, thanks to multiple instrumental characterization by means of ir, raman and nmr spectroscopy, the authors were able to identify the structure of the complex ( figure 68 ): a binuclear molecule [cu2(cca)4(h2o)2], where copper is coordinated by four carboxylic oxygens, one from each cca molecule and two water molecules. these results suggested that the introduction of halogens caused an increase in activity, depending on the number and the type of halogens. for instance, the 3,5-dichloro derivatives were more active against a. solani than the correspondent 5-cl or 5-br derivatives, probably because of an increase of hydrophobicity. the four coumarin-chitosan derivatives showed higher activity than chitosan alone also against f. oxysporum and f. moniliforme. compound 205d showed an inhibitory index of 57.09% against a. solani, 77.24% against f. oxysporum and 66.12% against f. moniliforme. the great biological potential of coumarins might be even increased by considering the possibility to complex coumarin scaffold with other substances as, for example, some metals. in fact, it has been proved that it is possible to enhance the activity of a certain drug simply binding it to a metallic-element [274] ; moreover, by combining known active moieties with metals, it would be possible to improve the parent compound with a certain selectivity or even with a new mechanism of action. therefore, many groups have already started to explore this strategy, aiming to produce more active compounds, exploiting metals as copper, platinum, zinc or silver. in some cases, due to its intrinsic potential, coumarin scaffold was exploited in this approach. some examples are discussed below. the nature of coumarin-copper complexes had already been evaluated in 2001 by karaliota and co-workers, who synthesized and characterized a binuclear coumarin-3-carboxilate-copper (ii) complex (206) [275] . in this work, thanks to multiple instrumental characterization by means of ir, raman and nmr spectroscopy, the authors were able to identify the structure of the complex ( figure 68 ): a binuclear molecule [cu 2 (cca) 4 (h 2 o) 2 ], where copper is coordinated by four carboxylic oxygens, one from each cca molecule and two water molecules. figure 69 ) which were tested on mcf-7 human breast cancer cells to evaluate their cytotoxicity [276] . in fact, the increase of ros levels might promote oxidative stressinduced cancer cell death, thus representing an alternative strategy for the treatment of some forms of tumors [277] [278] [279] . interestingly, it was found that the activity of such compounds depended also on their speciation; for example, 207, monomeric at neutral ph, showed valuable activity, whereas 212 -a dinuclear specie-resulted inactive. moreover, their cytotoxicity was not related to their ability to induce ros generation. such activity was showed only by complex 207, whereas 210 and 212 exhibited limited ros induction. 211 and 212 proved to be able to bind dna but none of the tested compounds showed significant nuclease activity. this means that imine-copper(ii) complexes showing cytotoxicity towards mcf-7 cells do not act by means of ros generation or nuclease activity, being these two the mechanisms of action previously ascribed to copper (ii) complexes [280] . in fact, complexes 208-210 acted as superoxide dismutase (sod) and catalase mimics. this is noteworthy, if we consider that in some cancer cells hypoxia induces an adaptive mechanism providing protection against damage and oxidative stress. in this context, copper (ii)-imine complexes acting as sod mimics may constitute a valid tool for the treatment of hypoxic tumors. in the same year, qin and collaborators investigated the potential of platinum (ii) complexes against cisplatin resistant human lung adenocarcinoma (a549/ddp) and hela cells [281] . cisplatin was used as reference. in this work, eleven complexes between platinum (ii) and quinoline-coumarin derivatives (214-224, figure 70) were designed, synthesized and tested. all the new complexes showed an improved antineoplastic activity on a549/ddp and hela cells when compared to cisfigure 69 ) which were tested on mcf-7 human breast cancer cells to evaluate their cytotoxicity [276] . in fact, the increase of ros levels might promote oxidative stress-induced cancer cell death, thus representing an alternative strategy for the treatment of some forms of tumors [277] [278] [279] . interestingly, it was found that the activity of such compounds depended also on their speciation; for example, 207, monomeric at neutral ph, showed valuable activity, whereas 212 -a dinuclear specie-resulted inactive. moreover, their cytotoxicity was not related to their ability to induce ros generation. such activity was showed only by complex 207, whereas 210 and 212 exhibited limited ros induction. 211 and 212 proved to be able to bind dna but none of the tested compounds showed significant nuclease activity. this means that imine-copper(ii) complexes showing cytotoxicity towards mcf-7 cells do not act by means of ros generation or nuclease activity, being these two the mechanisms of action previously ascribed to copper (ii) complexes [280] . in fact, complexes 208-210 acted as superoxide dismutase (sod) and catalase mimics. this is noteworthy, if we consider that in some cancer cells hypoxia induces an adaptive mechanism providing protection against damage and oxidative stress. in this context, copper (ii)-imine complexes acting as sod mimics may constitute a valid tool for the treatment of hypoxic tumors. figure 69 ) which were tested on mcf-7 human breast cancer cells to evaluate their cytotoxicity [276] . in fact, the increase of ros levels might promote oxidative stressinduced cancer cell death, thus representing an alternative strategy for the treatment of some forms of tumors [277] [278] [279] . interestingly, it was found that the activity of such compounds depended also on their speciation; for example, 207, monomeric at neutral ph, showed valuable activity, whereas 212 -a dinuclear specie-resulted inactive. moreover, their cytotoxicity was not related to their ability to induce ros generation. such activity was showed only by complex 207, whereas 210 and 212 exhibited limited ros induction. 211 and 212 proved to be able to bind dna but none of the tested compounds showed significant nuclease activity. this means that imine-copper(ii) complexes showing cytotoxicity towards mcf-7 cells do not act by means of ros generation or nuclease activity, being these two the mechanisms of action previously ascribed to copper (ii) complexes [280] . in fact, complexes 208-210 acted as superoxide dismutase (sod) and catalase mimics. this is noteworthy, if we consider that in some cancer cells hypoxia induces an adaptive mechanism providing protection against damage and oxidative stress. in this context, copper (ii)-imine complexes acting as sod mimics may constitute a valid tool for the treatment of hypoxic tumors. in the same year, qin and collaborators investigated the potential of platinum (ii) complexes against cisplatin resistant human lung adenocarcinoma (a549/ddp) and hela cells [281] . cisplatin was used as reference. in this work, eleven complexes between platinum (ii) and quinoline-coumarin derivatives (214-224, figure 70) were designed, synthesized and tested. all the new complexes showed an improved antineoplastic activity on a549/ddp and hela cells when compared to cisin the same year, qin and collaborators investigated the potential of platinum (ii) complexes against cisplatin resistant human lung adenocarcinoma (a549/ddp) and hela cells [281] . cisplatin was used as reference. in this work, eleven complexes between platinum (ii) and quinoline-coumarin derivatives (214-224, figure 70) were designed, synthesized and tested. all the new complexes showed an improved antineoplastic activity on a549/ddp and hela cells when compared to cis-pt(dmso) 2 cl 2 and the parent quinoline-coumarin derivatives, with ic 50 values ranging between 100 nm and 10. however, metal-coumarin complexes constitute an interesting tool not only in the pharmacological field but also in the chemical one. as an example of such application, we report here a work from aslkhademi and collaborators, who designed, synthesized ad characterized a new zn(ii) complex with a coumarin-hydrazone ligand (225, figure 71 ) [282] . in this case, the complex was evaluated as a catalyst for the synthesis of tetrazoles by means of 3 + 2 cycloaddition between a nitrile and an azide. to this purpose, many experiments were carried out using different nitriles and reaction conditions. in the end, the zn(ii)-coumarin-hydrazone complex resulted to be a suitable catalyst for the synthesis of tetrazoles; the most effective amount of catalyst to employ was 0.05 mmol and substrates bearing electron-donating groups reacted better than the ones with electronwithdrawing substituents. finally, it is worth mentioning the application of metal-coumarin complexes as constituents of sol-gel coatings. lately, sol-gels are gaining attention due to their chemical stability, homogeneity however, metal-coumarin complexes constitute an interesting tool not only in the pharmacological field but also in the chemical one. as an example of such application, we report here a work from aslkhademi and collaborators, who designed, synthesized ad characterized a new zn(ii) complex with a coumarin-hydrazone ligand (225, figure 71 ) [282] . in this case, the complex was evaluated as a catalyst for the synthesis of tetrazoles by means of 3 + 2 cycloaddition between a nitrile and an azide. to this purpose, many experiments were carried out using different nitriles and reaction conditions. in the end, the zn(ii)-coumarin-hydrazone complex resulted to be a suitable catalyst for the synthesis of tetrazoles; the most effective amount of catalyst to employ was 0.05 mmol and substrates bearing electron-donating groups reacted better than the ones with electron-withdrawing substituents. 100nm and 10.33 μm (75.02 ± 1.18 μm for a549/ddp or 12.09 ± 0.24 μm for hela). in addition, compounds 214-224 displayed selectivity towards the mentioned cancer cells over other tumoral cell lines and hl-7002 non-tumoral cell line. however, metal-coumarin complexes constitute an interesting tool not only in the pharmacological field but also in the chemical one. as an example of such application, we report here a work from aslkhademi and collaborators, who designed, synthesized ad characterized a new zn(ii) complex with a coumarin-hydrazone ligand (225, figure 71 ) [282] . in this case, the complex was evaluated as a catalyst for the synthesis of tetrazoles by means of 3 + 2 cycloaddition between a nitrile and an azide. to this purpose, many experiments were carried out using different nitriles and reaction conditions. in the end, the zn(ii)-coumarin-hydrazone complex resulted to be a suitable catalyst for the synthesis of tetrazoles; the most effective amount of catalyst to employ was 0.05 mmol and substrates bearing electron-donating groups reacted better than the ones with electronwithdrawing substituents. finally, it is worth mentioning the application of metal-coumarin complexes as constituents of sol-gel coatings. lately, sol-gels are gaining attention due to their chemical stability, homogeneity finally, it is worth mentioning the application of metal-coumarin complexes as constituents of sol-gel coatings. lately, sol-gels are gaining attention due to their chemical stability, homogeneity and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3-carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using ag-coumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. and technological applications (e.g., reservoir for the prolonged release of antimicrobial substances). in 2013, jaiswal and co-workers proposed the synthesis of silver-coumarin complexes useful as antibacterial agents in sol-gel coatings [283] . these complexes were based on coumarin-3carboxylatosilver and its hydroxylated derivatives in 6, 7 and 8. antimicrobial activity was displayed even at concentration of 0.3% (w/w). the most active compound showed significative antibiofilm activity at 0.5% and 0.7% (w/w). these results are encouraging in the perspective of using agcoumarin complexes as biomedical coatings. table 2 reports some of the coumarins mentioned above, summarizing the biological activity, the molecular target and the origin. knoevenagel condensation, wittig reaction, claisen rearrangement, heck reaction, pechmann condensation and perkin reaction are widely used methods for the obtainment of coumarin derivatives and have been widely reviewed over the years [284, 285] . the increasing interest in coumarins as potential biologically active compounds led to the development of innovative knoevenagel condensation, wittig reaction, claisen rearrangement, heck reaction, pechmann condensation and perkin reaction are widely used methods for the obtainment of coumarin derivatives and have been widely reviewed over the years [284, 285] . the increasing interest in coumarins as potential biologically active compounds led to the development of innovative knoevenagel condensation, wittig reaction, claisen rearrangement, heck reaction, pechmann condensation and perkin reaction are widely used methods for the obtainment of coumarin derivatives and have been widely reviewed over the years [284, 285] . the increasing interest in coumarins as potential biologically active compounds led to the development of innovative procedures and approaches aimed at the production of coumarins in high yield and in a sustainable manner. in the next paragraphs, we will focus on the most recent advances in coumarin synthesis. in the past two decades, flow chemistry emerged has a promising synthetic technology, due to the many advantages it offers compared to the traditional batch method. in fact, by using continuous flow reactors it is possible to control reaction parameters, such as temperature, stoichiometry, reaction time and others, very precisely, thus having the possibility to achieve better and more reproducible reactions. furthermore, the great surface area/volume ratio in continuous flow reactors often leads to better reaction yields. this new technology gives also the possibility to work with hazardous reagents and to perform superheated or pressurized reactions in safer conditions [286] [287] [288] . the applications of this technology are numerous and the improvement of chemical synthesis of natural compounds is one of them. in 2015, li and collaborators developed a two-stage synthesis of coumarins via o-acetylation of salicylaldehyde [289] . the reaction occurred via o-acetylation and intramolecular aldol-type condensation, followed by dehydration and it was performed using two heated coiled reactors (scheme 1). using this system, it was possible to reach a 120 g scale production. procedures and approaches aimed at the production of coumarins in high yield and in a sustainable manner. in the next paragraphs, we will focus on the most recent advances in coumarin synthesis. in the past two decades, flow chemistry emerged has a promising synthetic technology, due to the many advantages it offers compared to the traditional batch method. in fact, by using continuous flow reactors it is possible to control reaction parameters, such as temperature, stoichiometry, reaction time and others, very precisely, thus having the possibility to achieve better and more reproducible reactions. furthermore, the great surface area/volume ratio in continuous flow reactors often leads to better reaction yields. this new technology gives also the possibility to work with hazardous reagents and to perform superheated or pressurized reactions in safer conditions [286] [287] [288] . the applications of this technology are numerous and the improvement of chemical synthesis of natural compounds is one of them. in 2015, li and collaborators developed a two-stage synthesis of coumarins via o-acetylation of salicylaldehyde [289] . the reaction occurred via o-acetylation and intramolecular aldol-type condensation, followed by dehydration and it was performed using two heated coiled reactors (scheme 1). using this system, it was possible to reach a 120 g scale production. the use of immobilized reagents in organic synthesis is gaining ever more attention, due to the advantages offered by such type of reagents (for example, the simplification of product isolation and purification). this synthetic strategy has seen some applications in the production of natural scaffolds too. in 2018, mhiri and co-workers proposed a synthetic pathway for coumarin derivatives involving polymer supported reagents [290] . in the mentioned study, coumarin derivative a was prepared from 3-metoxy salicylaldheyde using reagents supported in a macroporous ion exchange resin, through the hydrolysis of the two intermediates iminocoumarin b and unsaturated nitrile c (scheme 2). the use of immobilized reagents in organic synthesis is gaining ever more attention, due to the advantages offered by such type of reagents (for example, the simplification of product isolation and purification). this synthetic strategy has seen some applications in the production of natural scaffolds too. in 2018, mhiri and co-workers proposed a synthetic pathway for coumarin derivatives involving polymer supported reagents [290] . in the mentioned study, coumarin derivative a was prepared from 3-metoxy salicylaldheyde using reagents supported in a macroporous ion exchange resin, through the hydrolysis of the two intermediates iminocoumarin b and unsaturated nitrile c (scheme 2). scheme 1. set-up for the synthesis of coumarins via o-acetylation of salicylaldehyde in a continuous flow reactor. the use of immobilized reagents in organic synthesis is gaining ever more attention, due to the advantages offered by such type of reagents (for example, the simplification of product isolation and purification). this synthetic strategy has seen some applications in the production of natural scaffolds too. in 2018, mhiri and co-workers proposed a synthetic pathway for coumarin derivatives involving polymer supported reagents [290] . in the mentioned study, coumarin derivative a was prepared from 3-metoxy salicylaldheyde using reagents supported in a macroporous ion exchange resin, through the hydrolysis of the two intermediates iminocoumarin b and unsaturated nitrile c (scheme 2). coumarin synthesis with polymer-supported reagent. coumarin synthesis with polymer-supported reagent. the first step provided the preparation of polymer supported phenate ions that then reacted with phenylacetonitrile, leading to the formation of iminocoumarin and unsaturated nitrile, which were finally deblocked from the resin with chloroform. the acid hydrolysis of the obtained mixture of compounds b and c gave coumarin derivative a in very good yield (95%). it is worth speaking about another emerging strategy in organic synthesis: photocatalysis. in 2015, metternich and gilmour utilized this approach to emulate coumarins biosynthesis, using (−)-riboflavin as a photocatalyst [291] . in this work, two discrete activation modes of (−)-riboflavin were sequentially exploited to induce the isomerization and cyclisation of e-cinnamic acids used as starting material (scheme 3), thus overcoming the use of phenol-derived and pre-functionalized aryl rings as starting materials. the first step provided the preparation of polymer supported phenate ions that then reacted with phenylacetonitrile, leading to the formation of iminocoumarin and unsaturated nitrile, which were finally deblocked from the resin with chloroform. the acid hydrolysis of the obtained mixture of compounds b and c gave coumarin derivative a in very good yield (95%). it is worth speaking about another emerging strategy in organic synthesis: photocatalysis. in 2015, metternich and gilmour utilized this approach to emulate coumarins biosynthesis, using (−)riboflavin as a photocatalyst [291] . in this work, two discrete activation modes of (−)-riboflavin were sequentially exploited to induce the isomerization and cyclisation of e-cinnamic acids used as starting material (scheme 3), thus overcoming the use of phenol-derived and pre-functionalized aryl rings as starting materials. similarly, in 2019, song and co-workers reported a one-pot photoredox-catalyzed protocol to achieve a series of 3-fluoroalkylated coumarins starting from ortho-hydroxycinnamic esters (scheme 4) [292] . ortho-hydroxycinnamic esters and brcf2cor' (or other commercially available perfluoroalkylated radical resources) were exposed to 30w blue leds irradiation under argon atmosphere for 12 h.; fac-ir(ppy)3 was found to be the best among the tested catalysts, whereas ch3cn, dmf, dmso and thf were all suitable solvents for this reaction. k2co3, et3n and dipea were all able to neutralize hbr produced during the process. this procedure gave 3-fluoroalkylated coumarins in good yields on milligram and gram scales. similarly, in 2019, song and co-workers reported a one-pot photoredox-catalyzed protocol to achieve a series of 3-fluoroalkylated coumarins starting from ortho-hydroxycinnamic esters (scheme 4) [292] . ortho-hydroxycinnamic esters and brcf 2 cor' (or other commercially available perfluoroalkylated radical resources) were exposed to 30w blue leds irradiation under argon atmosphere for 12 h.; fac-ir(ppy) 3 was found to be the best among the tested catalysts, whereas ch 3 cn, dmf, dmso and thf were all suitable solvents for this reaction. k 2 co 3 , et 3 n and dipea were all able to neutralize hbr produced during the process. this procedure gave 3-fluoroalkylated coumarins in good yields on milligram and gram scales. perfluoroalkylated radical resources) were exposed to 30w blue leds irradiation under argon atmosphere for 12 h.; fac-ir(ppy)3 was found to be the best among the tested catalysts, whereas ch3cn, dmf, dmso and thf were all suitable solvents for this reaction. k2co3, et3n and dipea were all able to neutralize hbr produced during the process. this procedure gave 3-fluoroalkylated coumarins in good yields on milligram and gram scales. another example is the bichromatic synthesis of coumarins proposed by eivgi and collaborators in 2017 [293] . in this work, 2-nitrobenzyl-protected 2-hydroxystyrenes and acrylates underwent a uv-a (380 nm) photoinduced cross metathesis (cm) reaction, in the presence of ruthenium as a catalyst. in this step a 1-pyrenecarboxaldheyde solution was used as a uv filter, without whom the catalyst would be permanently inactivated due to phenol deprotection and phenolate chelation to the ruthenium. after cm, the uv filter was removed and irradiation with uv-c light (254 nm) led to more complex structures, such as coumarins. in fact, irradiation with uv-c light started a threereactions chain-photodeprotection of the intermediate, e/z isomerization and cyclization to form the desired coumarins (scheme 5). another example is the bichromatic synthesis of coumarins proposed by eivgi and collaborators in 2017 [293] . in this work, 2-nitrobenzyl-protected 2-hydroxystyrenes and acrylates underwent a uv-a (380 nm) photoinduced cross metathesis (cm) reaction, in the presence of ruthenium as a catalyst. in this step a 1-pyrenecarboxaldheyde solution was used as a uv filter, without whom the catalyst would be permanently inactivated due to phenol deprotection and phenolate chelation to the ruthenium. after cm, the uv filter was removed and irradiation with uv-c light (254 nm) led to more complex structures, such as coumarins. in fact, irradiation with uv-c light started a three-reactions chain-photodeprotection of the intermediate, e/z isomerization and cyclization to form the desired coumarins (scheme 5). chemists usually carry out reactions in solution, following the aristotelian principle "corpora non agunt nisi fluida seu soluta" or in other and more contemporary words "compounds do not react unless fluid or if dissolved" [294] . however, this is not always completely accurate, because many solventless reactions proceed efficiently. an enhancement in kinetics, owed to the different concentrations of reactants given the lack of solvents, bring actually to a higher reactivity and, where necessary, milder experimental conditions. at the same time, the absence of solvents provides the chance to heat over the boiling point of the most common solvents and to exploit the benefits of microwave assisted irradiation. the occurrence of efficient solid-state reactions shows that the reacting molecules are able to move freely in the solid state, whereas monitoring of the reaction is possible thanks ir and uv spectra in the solid state [295, 296] . the most remarkable advantage of solvent-free reaction, in all probability, is the noteworthy cut in the waste production associated with solvents handling, resulting in a more effective and ecological chemical process. there are three solvent-free techniques: (1) reactions conducted on mineral supports, (2) reaction without any solvent, support or catalyst and (3) solid-liquid phase transfer catalysis [297] . the experimental conditions required for the classical synthesis of coumarin derivatives are, in some cases, drastic, as in the production of hymecromone via pechmann condensation where the final compound is obtain by stirring a mixture of resorcinol and ethyl acetoacetate in concentrated h2so4 for 12-24 h [295] . solvent-free reactions seemed to be a more ecological option. consequently, in 2001, sugino and tanaka proposed the synthesis of several coumarin derivatives both via pechmann and knoevenagel condensation reactions [298] . for example, p-toluensolfonic acid was employed as a catalyst and the reaction mixture was heated at 60 °c for 10 min. without solvent, chemists usually carry out reactions in solution, following the aristotelian principle "corpora non agunt nisi fluida seu soluta" or in other and more contemporary words "compounds do not react unless fluid or if dissolved" [294] . however, this is not always completely accurate, because many solventless reactions proceed efficiently. an enhancement in kinetics, owed to the different concentrations of reactants given the lack of solvents, bring actually to a higher reactivity and, where necessary, milder experimental conditions. at the same time, the absence of solvents provides the chance to heat over the boiling point of the most common solvents and to exploit the benefits of microwave assisted irradiation. the occurrence of efficient solid-state reactions shows that the reacting molecules are able to move freely in the solid state, whereas monitoring of the reaction is possible thanks ir and uv spectra in the solid state [295, 296] . the most remarkable advantage of solvent-free reaction, in all probability, is the noteworthy cut in the waste production associated with solvents handling, resulting in a more effective and ecological chemical process. there are three solvent-free techniques: (1) reactions conducted on mineral supports, (2) reaction without any solvent, support or catalyst and (3) solid-liquid phase transfer catalysis [297] . the experimental conditions required for the classical synthesis of coumarin derivatives are, in some cases, drastic, as in the production of hymecromone via pechmann condensation where the final compound is obtain by stirring a mixture of resorcinol and ethyl acetoacetate in concentrated h2so4 for 12-24 h [295] . solvent-free reactions seemed to be a more ecological option. consequently, in 2001, sugino and tanaka proposed the synthesis of several coumarin derivatives both via pechmann and knoevenagel condensation reactions [298] . for example, p-toluensolfonic acid was employed as a catalyst and the reaction mixture was heated at 60 • c for 10 min. without solvent, giving after the work-up 7-hydroxy-4-methylcoumarin in 98% yield (scheme 6). the experimental conditions required for the classical synthesis of coumarin derivatives are, in some cases, drastic, as in the production of hymecromone via pechmann condensation where the final compound is obtain by stirring a mixture of resorcinol and ethyl acetoacetate in concentrated h2so4 for 12-24 h [295] . solvent-free reactions seemed to be a more ecological option. consequently, in 2001, sugino and tanaka proposed the synthesis of several coumarin derivatives both via pechmann and knoevenagel condensation reactions [298] . for example, p-toluensolfonic acid was employed as a catalyst and the reaction mixture was heated at 60 °c for 10 min. without solvent, giving after the work-up 7-hydroxy-4-methylcoumarin in 98% yield (scheme 6). scheme 6. solvent-free synthesis of 7-hydroxy-4-methylcoumarin. scheme 6. solvent-free synthesis of 7-hydroxy-4-methylcoumarin. knoevenagel condensation was also studied under solventless conditions and efficiently brought to the production of both coumarins and benzocoumarin derivatives [298] . another methodology was proposed in 2012 by kalita and kumar, that exploited the pechmann reaction using trifluoromethanesulfonic acid functionalized zr-tms (zr-tms, zirconia-based transition metal oxide mesoporous molecular sieves) catalysts, under solvent-free heterogeneous catalytic conditions. the product selectivity was always found to be about 100% (scheme 7) [296] . knoevenagel condensation was also studied under solventless conditions and efficiently brought to the production of both coumarins and benzocoumarin derivatives [298] . another methodology was proposed in 2012 by kalita and kumar, that exploited the pechmann reaction using trifluoromethanesulfonic acid functionalized zr-tms (zr-tms, zirconia-based transition metal oxide mesoporous molecular sieves) catalysts, under solvent-free heterogeneous catalytic conditions. the product selectivity was always found to be about 100% (scheme 7) [296] . more recently, a novel series of hetero-annulated coumarins was obtained by ebrahimi and colleagues through a one-pot reaction under solvent-free conditions and evaluated as ache/buche inhibitors. as acidic catalyst nano-silica sulfuric acid was employed and the versatility of the system was assayed on appropriated benzaldehydes, dimedone and 4-hydroxycoumarin (scheme 8) [299] . also noteworthy is the application, once again, of a reusable heterogeneous catalyst, which contributed to the general environmental sustainability of the process thanks to the possible recovery and reuse [300] . scheme 8. solvent-free synthesis of hetero-annulated coumarins. another solventless procedure worth noting is the one presented by kour and paul, which exploited lewis acid grafted sulfonated carbon@titania composite as catalyst for the pechmann condensation. this particular kind of catalyst and its efficacy had been already studied by the team more recently, a novel series of hetero-annulated coumarins was obtained by ebrahimi and colleagues through a one-pot reaction under solvent-free conditions and evaluated as ache/buche inhibitors. as acidic catalyst nano-silica sulfuric acid was employed and the versatility of the system was assayed on appropriated benzaldehydes, dimedone and 4-hydroxycoumarin (scheme 8) [299] . also noteworthy is the application, once again, of a reusable heterogeneous catalyst, which contributed to the general environmental sustainability of the process thanks to the possible recovery and reuse [300] . knoevenagel condensation was also studied under solventless conditions and efficiently brought to the production of both coumarins and benzocoumarin derivatives [298] . another methodology was proposed in 2012 by kalita and kumar, that exploited the pechmann reaction using trifluoromethanesulfonic acid functionalized zr-tms (zr-tms, zirconia-based transition metal oxide mesoporous molecular sieves) catalysts, under solvent-free heterogeneous catalytic conditions. the product selectivity was always found to be about 100% (scheme 7) [296] . more recently, a novel series of hetero-annulated coumarins was obtained by ebrahimi and colleagues through a one-pot reaction under solvent-free conditions and evaluated as ache/buche inhibitors. as acidic catalyst nano-silica sulfuric acid was employed and the versatility of the system was assayed on appropriated benzaldehydes, dimedone and 4-hydroxycoumarin (scheme 8) [299] . also noteworthy is the application, once again, of a reusable heterogeneous catalyst, which contributed to the general environmental sustainability of the process thanks to the possible recovery and reuse [300] . another solventless procedure worth noting is the one presented by kour and paul, which exploited lewis acid grafted sulfonated carbon@titania composite as catalyst for the pechmann condensation. this particular kind of catalyst and its efficacy had been already studied by the team for the synthesis of 4h-pyrimido[2,1-b]benzothiazoles and benzoxanthenones under solvent-free conditions, so the one-pot synthesis of coumarin derivatives was the natural next step (scheme 9) [301, 302] . because the catalyst reusability contributes to reduce the cost of the practical application processes, the reusability of the catalyst was investigated in the pechmann condensation. the catalyst, another solventless procedure worth noting is the one presented by kour and paul, which exploited lewis acid grafted sulfonated carbon@titania composite as catalyst for the pechmann condensation. this particular kind of catalyst and its efficacy had been already studied by the team for the synthesis of 4h-pyrimido[2,1-b]benzothiazoles and benzoxanthenones under solvent-free conditions, so the one-pot synthesis of coumarin derivatives was the natural next step (scheme 9) [301, 302] . because the catalyst reusability contributes to reduce the cost of the practical application processes, the reusability of the catalyst was investigated in the pechmann condensation. the catalyst, recovered by filtration, after five catalytic runs had a mild decrease in the catalytic activity and exhibited almost the same tg curve as the fresh one, depicting that the present heterogeneous system showed high thermal stability after successive reaction cycles [302] . in order to obtain a different and ecological procedure for the synthesis of 3-substituted coumarins via knoevenagel condensation, ghomi and akbarzadeh developed a procedure starting from various salicylaldehydes and 1,3-dicarbonyl compounds. they used mgfe2o4 nanoparticles as an efficient catalyst under solvent-free condition and ultrasound irradiation (scheme 10). basically, ultrasound irradiation increased the dimension of the single bubbles together with the number of active cavitation bubbles. the resulting effect was expected to be a higher maximum collapse temperature and a faster synthesis of coumarin compounds by knoevenagel reaction. comparing ultrasound irradiation to conventional heating the research team demonstrated that the first method allowed to obtain higher yields in shorter times, probably because of the shock wave and microjet generated by the cavitation. furthermore, with this method, mgfe2o4 nanoparticles were dispersed in the reaction and provided more sites for the construction of cavity over their surface. the catalyst was recovered via magnetic separation and reused up to 6 cycles without relevant loss of activity [303] . the convenience given by the removal of the catalyst by means of an external magnetic field is a significant improvement in the work-up of a reaction mixture. consequently, another magnetic nano structured catalyst was employed for the synthesis of coumarin nucleus, this time through pechmann condensation. in 2019, pakdel and co-workers proposed the synthesis of coumarin derivatives by leveraging fe3o4@boehmite-nh2-coii nps as a catalyst, under solvent-free conditions that resulted the best choice comparing the results obtained with classic solvents. the catalyst could be recovered easily and reused up to six times. however, no desired coumarin derivatives were observed in the case of phenols bearing electron-withdrawing substituents (such as -cl and -no2), behavior attributed to the proposed mechanism of the reaction [304] . in the field of solvent-free reactions, the application of ionic liquids as catalyst for the synthesis of coumarin scaffolds deserves a stand-alone status. ionic liquids (ils) have become increasingly popular in the last decades as a safer alternative to classic solvent systems, in a perspective of more sustainable chemical processes. most ils possess a number of properties that made them appealing, proving to be non-flammable, to possess a negligible vapor-pressure, that means that solvent evaporation is eliminated and to dissolve a wide range of organic and inorganic compounds [305] . furthermore, since ionic liquids are low-melting salts, they are made at least from two components which can be varied (the anion and the cation), thus the solvents could be designed with a particular end use in mind or possessing a particular set of properties [306] . however, their use in large quantities is restricted by some limitations like biodegradability, toxicity and high costs [307] [308] [309] . mahato and colleagues in 2017 used ionic liquids as an acidic catalyst in the regioselective synthesis of pyrano [3,2-c] coumarins under solvent-free conditions. in particular, given the fact that brønsted acidic ion liquids (bails) acquired recognition in the field of catalysis, the research team reported the catalytic effect of 1-butane sulfonic acid-3-methylimidazolium tosylate, [bsmim]ots (bail-1), on the tandem reaction between 4-hydroxycoumarin and α,β-unsaturated carbonyl compounds for the formation of pyrano[3,2-c]coumarins (scheme 10) [310, 311] . in addition to the high yields and the regioselectivity, this procedure allowed to avoid column chromatography for further purification. lewis acid grafted sulfonated carbon@titania composite as catalyst for the pechmann condensation. in order to obtain a different and ecological procedure for the synthesis of 3-substituted coumarins via knoevenagel condensation, ghomi and akbarzadeh developed a procedure starting from various salicylaldehydes and 1,3-dicarbonyl compounds. they used mgfe 2 o 4 nanoparticles as an efficient catalyst under solvent-free condition and ultrasound irradiation (scheme 10). noroozizadeh and co-workers focused their efforts on the synthesis of bis-coumarins thanks to a different catalyst, acetic acid functionalized poly(4-vinylpyridinum) bromide (apvpb), in continuous of a previous work of the research team on the preparation of brønsted acidic ionic liquids and solid salts [312, 313] . the aim was the development of a novel and efficient procedure for the synthesis of bis-coumarins which lacked the classical drawbacks as the use of solvents, high costs and low yields [314] . temperature is a key parameter in almost the totality of chemical reactions involving both inorganic and organic compounds. generally, most organic reactions are performed heating by traditional heat transfer equipment like oil baths, sand baths and heating jackets. the drawbacks associated with these heating techniques are the slowness, the possible development of temperature gradient within the sample and consequent local overheating that could lead to the formation of byproducts. microwave technology started to emerge in inorganic chemistry since the late 1970s and almost a decade after attracted the attention of organic chemists [315] . compared to the traditional heating, microwave dielectric heating has several advantages: (1) higher heating rates, (2) no direct contact between the source of energy and the reacting chemicals, (3) possible selective heating, because reacting chemicals interact differently with the commonly used microwave radiations and (4) rapid increase of the temperature also above boiling point in pressurized systems [316] . microwave irradiation is often associated with other technologies, such as ionic liquids and neat reactions (already mentioned in the previous paragraph) [295, 317] . in the late 1990s progresses in the classic coumarins synthesis via microwave irradiation were reported by singh and co-workers, who confirmed a reduction in reaction time of the pechmann condensation and by saidi and colleagues, who demonstrated the improvement in the synthesis of pyranocoumarins and furanocoumarins through claisen rearrangement [317, 318] . ten years later, valizadeh and shockravi pushed further the opportunities given by microwave heating combining it with a task-specific imidazolium-based phosphinite ionic liquid (il-opph2) for the synthesis of e-cinnamates and coumarin derivatives via basically, ultrasound irradiation increased the dimension of the single bubbles together with the number of active cavitation bubbles. the resulting effect was expected to be a higher maximum collapse temperature and a faster synthesis of coumarin compounds by knoevenagel reaction. comparing ultrasound irradiation to conventional heating the research team demonstrated that the first method allowed to obtain higher yields in shorter times, probably because of the shock wave and microjet generated by the cavitation. furthermore, with this method, mgfe2o4 nanoparticles were dispersed in the reaction and provided more sites for the construction of cavity over their surface. the catalyst was recovered via magnetic separation and reused up to 6 cycles without relevant loss of activity [303] . the convenience given by the removal of the catalyst by means of an external magnetic field is a significant improvement in the work-up of a reaction mixture. consequently, another magnetic nano structured catalyst was employed for the synthesis of coumarin nucleus, this time through pechmann condensation. in 2019, pakdel and co-workers proposed the synthesis of coumarin derivatives by leveraging fe 3 o 4 @boehmite-nh 2 -coii nps as a catalyst, under solvent-free conditions that resulted the best choice comparing the results obtained with classic solvents. the catalyst could be recovered easily and reused up to six times. however, no desired coumarin derivatives were observed in the case of phenols bearing electron-withdrawing substituents (such as -cl and -no2), behavior attributed to the proposed mechanism of the reaction [304] . in the field of solvent-free reactions, the application of ionic liquids as catalyst for the synthesis of coumarin scaffolds deserves a stand-alone status. ionic liquids (ils) have become increasingly popular in the last decades as a safer alternative to classic solvent systems, in a perspective of more sustainable chemical processes. most ils possess a number of properties that made them appealing, proving to be non-flammable, to possess a negligible vapor-pressure, that means that solvent evaporation is eliminated and to dissolve a wide range of organic and inorganic compounds [305] . furthermore, since ionic liquids are low-melting salts, they are made at least from two components which can be varied (the anion and the cation), thus the solvents could be designed with a particular end use in mind or possessing a particular set of properties [306] . however, their use in large quantities is restricted by some limitations like biodegradability, toxicity and high costs [307] [308] [309] . mahato and colleagues in 2017 used ionic liquids as an acidic catalyst in the regioselective synthesis of pyrano [3,2-c] coumarins under solvent-free conditions. in particular, given the fact that brønsted acidic ion liquids (bails) acquired recognition in the field of catalysis, the research team reported the catalytic effect of 1-butane sulfonic acid-3-methylimidazolium tosylate, [bsmim]ots (bail-1), on the tandem reaction between 4-hydroxycoumarin and α,β-unsaturated carbonyl compounds for the formation of pyrano[3,2-c]coumarins (scheme 10) [310, 311] . in addition to the high yields and the regioselectivity, this procedure allowed to avoid column chromatography for further purification. moreover, given the mild experimental conditions, there were no by-products attributable to decomposition or polymerization. noroozizadeh and co-workers focused their efforts on the synthesis of bis-coumarins thanks to a different catalyst, acetic acid functionalized poly(4-vinylpyridinum) bromide (apvpb), in continuous of a previous work of the research team on the preparation of brønsted acidic ionic liquids and solid salts [312, 313] . the aim was the development of a novel and efficient procedure for the synthesis of bis-coumarins which lacked the classical drawbacks as the use of solvents, high costs and low yields [314] . temperature is a key parameter in almost the totality of chemical reactions involving both inorganic and organic compounds. generally, most organic reactions are performed heating by traditional heat transfer equipment like oil baths, sand baths and heating jackets. the drawbacks associated with these heating techniques are the slowness, the possible development of temperature gradient within the sample and consequent local overheating that could lead to the formation of by-products. microwave technology started to emerge in inorganic chemistry since the late 1970s and almost a decade after attracted the attention of organic chemists [315] . compared to the traditional heating, microwave dielectric heating has several advantages: (1) higher heating rates, (2) no direct contact between the source of energy and the reacting chemicals, (3) possible selective heating, because reacting chemicals interact differently with the commonly used microwave radiations and (4) rapid increase of the temperature also above boiling point in pressurized systems [316] . microwave irradiation is often associated with other technologies, such as ionic liquids and neat reactions (already mentioned in the previous paragraph) [295, 317] . in the late 1990s progresses in the classic coumarins synthesis via microwave irradiation were reported by singh and co-workers, who confirmed a reduction in reaction time of the pechmann condensation and by saidi and colleagues, who demonstrated the improvement in the synthesis of pyranocoumarins and furanocoumarins through claisen rearrangement [317, 318] . ten years later, valizadeh and shockravi pushed further the opportunities given by microwave heating combining it with a task-specific imidazolium-based phosphinite ionic liquid (il-opph 2 ) for the synthesis of e-cinnamates and coumarin derivatives via the one-pot horner-wadsworth-emmons-type reaction (scheme 11). moreover, given the mild experimental conditions, there were no by-products attributable to decomposition or polymerization. noroozizadeh and co-workers focused their efforts on the synthesis of bis-coumarins thanks to a different catalyst, acetic acid functionalized poly(4-vinylpyridinum) bromide (apvpb), in continuous of a previous work of the research team on the preparation of brønsted acidic ionic liquids and solid salts [312, 313] . the aim was the development of a novel and efficient procedure for the synthesis of bis-coumarins which lacked the classical drawbacks as the use of solvents, high costs and low yields [314] . temperature is a key parameter in almost the totality of chemical reactions involving both inorganic and organic compounds. generally, most organic reactions are performed heating by traditional heat transfer equipment like oil baths, sand baths and heating jackets. the drawbacks associated with these heating techniques are the slowness, the possible development of temperature gradient within the sample and consequent local overheating that could lead to the formation of byproducts. microwave technology started to emerge in inorganic chemistry since the late 1970s and almost a decade after attracted the attention of organic chemists [315] . compared to the traditional heating, microwave dielectric heating has several advantages: (1) higher heating rates, (2) no direct contact between the source of energy and the reacting chemicals, (3) possible selective heating, because reacting chemicals interact differently with the commonly used microwave radiations and (4) rapid increase of the temperature also above boiling point in pressurized systems [316] . microwave irradiation is often associated with other technologies, such as ionic liquids and neat reactions (already mentioned in the previous paragraph) [295, 317] . in the late 1990s progresses in the classic coumarins synthesis via microwave irradiation were reported by singh and co-workers, who confirmed a reduction in reaction time of the pechmann condensation and by saidi and colleagues, who demonstrated the improvement in the synthesis of pyranocoumarins and furanocoumarins through claisen rearrangement [317, 318] . ten years later, valizadeh and shockravi pushed further the opportunities given by microwave heating combining it with a task-specific imidazolium-based phosphinite ionic liquid (il-opph2) for the synthesis of e-cinnamates and coumarin derivatives via the one-pot horner-wadsworth-emmons-type reaction (scheme 11). scheme 11. imidazolium-based phosphinite ionic liquid (il-opph2) for the microwave assisted synthesis of coumarins. the same reactions were in parallel conducted with traditional heating and microwave irradiation: the former technique showed considerably longer reaction times (13) (14) (15) (16) the same reactions were in parallel conducted with traditional heating and microwave irradiation: the former technique showed considerably longer reaction times (13-16 h vs. 10-12 min) and lower yields (65-60% vs. 79-83%). furthermore, il-opph 2 worked at the same time as reaction medium and reagent as the research team already demonstrated in a previous study focused on the synthesis of coumarin nucleus via knoevenagel and witting reactions in ionic liquids [319, 320] . in 2016, fiorito and colleagues merged the advantages of solvent-free reactions with microwave heating for the synthesis of several coumarin derivatives. they started from variously substituted phenols and propiolic acids in the presence of ytterbium triflate hydrate 10% mol as catalyst [321] . during the last thirty years, triflates of metals belonging to the lanthanide series have been regarded as effective water tolerant recyclable lewis acids. these metals have been discovered to catalyze different carbon-carbon and carbon-heteroatom bond formation reactions, providing the desired products in excellent yields by means of a green chemical approach [322, 323] . furthermore, wang and colleagues already employed this particular catalyst for the synthesis of 4-methylcoumarins via pechmann condensation [324] . fiorito and co-workers developed for the first time a synthetic procedure to obtain different substituted coumarins in 2 min. under microwave irradiation in 91-98% yields [321] . moreover, the research team recovered the ytterbium triflate catalyst and demonstrated that no loss of activity occurred during several cycles. in the same year, bouasla et al. compared the efficacy of different heterogeneous acidic catalysts in the pechmann synthesis of 4-methylcoumarin and 7-hydroxy-4-methylcoumarin when coupled by microwave heating. the efficacy of different amberylst-type catalyst in the pechmann synthesis of 7-hydroxy-4-methylcoumarin was already pointed out by sabou and colleagues in 2005 [325] . therefore, the catalytic performance of amberlyst-15 was compared with zeolite h-β and sulfonic acid functionalized hybrid material ts-os-so 3 h, performing the reaction under solvent-free conditions, at 130 • c for 20 min in a microwave reaction tube. amberlyst-15 showed a higher catalytic activity (97% yield against 21-44% obtained with two others catalysts) due to its high density of acid centers [326] . it is also worth mentioning the work of konrádová et al., who in 2017 developed an interesting protecting-group-free method starting from commercially available aromatic aldehydes and using a microwave promoted wittig reaction of a stabilized ylide for the synthesis of different natural products, including coumarins. after the optimization of the experimental parameters and the development of a general synthetic methodology for the synthesis of different substitute coumarin derivatives (scheme 12a), the method was further developed to incorporate a claisen rearrangement step. in order to demonstrate the synthetic utility and versatility of the developed method, the research team performed the total synthesis of two coumarins, one of which being osthole, a natural coumarin derivative already mentioned in the anti-inflammatory paragraph (scheme 12b) [327] . and lower yields (65-60% vs 79-83%). furthermore, il-opph2 worked at the same time as reaction medium and reagent as the research team already demonstrated in a previous study focused on the synthesis of coumarin nucleus via knoevenagel and witting reactions in ionic liquids [319, 320] . in 2016, fiorito and colleagues merged the advantages of solvent-free reactions with microwave heating for the synthesis of several coumarin derivatives. they started from variously substituted phenols and propiolic acids in the presence of ytterbium triflate hydrate 10% mol as catalyst [321] . during the last thirty years, triflates of metals belonging to the lanthanide series have been regarded as effective water tolerant recyclable lewis acids. these metals have been discovered to catalyze different carbon-carbon and carbon-heteroatom bond formation reactions, providing the desired products in excellent yields by means of a green chemical approach [322, 323] . furthermore, wang and colleagues already employed this particular catalyst for the synthesis of 4-methylcoumarins via pechmann condensation [324] . fiorito and co-workers developed for the first time a synthetic procedure to obtain different substituted coumarins in 2 min. under microwave irradiation in 91-98% yields [321] . moreover, the research team recovered the ytterbium triflate catalyst and demonstrated that no loss of activity occurred during several cycles. in the same year, bouasla et al. compared the efficacy of different heterogeneous acidic catalysts in the pechmann synthesis of 4-methylcoumarin and 7-hydroxy-4-methylcoumarin when coupled by microwave heating. the efficacy of different amberylst-type catalyst in the pechmann synthesis of 7hydroxy-4-methylcoumarin was already pointed out by sabou and colleagues in 2005 [325] . therefore, the catalytic performance of amberlyst-15 was compared with zeolite h-β and sulfonic acid functionalized hybrid material ts-os-so3h, performing the reaction under solvent-free conditions, at 130 °c for 20 min in a microwave reaction tube. amberlyst-15 showed a higher catalytic activity (97% yield against 21-44% obtained with two others catalysts) due to its high density of acid centers [326] . it is also worth mentioning the work of konrádová et al., who in 2017 developed an interesting protecting-group-free method starting from commercially available aromatic aldehydes and using a microwave promoted wittig reaction of a stabilized ylide for the synthesis of different natural products, including coumarins. after the optimization of the experimental parameters and the development of a general synthetic methodology for the synthesis of different substitute coumarin derivatives (scheme 12a), the method was further developed to incorporate a claisen rearrangement step. in order to demonstrate the synthetic utility and versatility of the developed method, the research team performed the total synthesis of two coumarins, one of which being osthole, a natural coumarin derivative already mentioned in the anti-inflammatory paragraph (scheme 12b) [327] . a broad range of indolo [2,3-c] coumarins have been obtained in good yields (46-88%) by gu and co-workers in 2019 under microwave-assisted base-free intramolecular cross dehydrogenative coupling using palladium catalyst. the advantages of this methodologies compared to classic a broad range of indolo [2,3-c] coumarins have been obtained in good yields (46-88%) by gu and co-workers in 2019 under microwave-assisted base-free intramolecular cross dehydrogenative coupling using palladium catalyst. the advantages of this methodologies compared to classic synthesis of coumarin lactone ring were both atom economy and step efficiency, combined with c-h/c-h coupling without pre-functionalization [328] . the coumarin nucleus has been gaining increasing attention in the last years because of the variety of its applications both in medicinal chemistry and in agri-food sectors. in this review, we presented a collection of recent works that highlight the wide range of pharmacological activities ascribable to coumarins (antioxidant, antibacterial, antifungal, antiviral, anti-proliferative, anti-inflammatory, antidiabetics, anticoagulant and anti-neurodegenerative) and the possibility to easily modify and decorate this natural scaffold to perform structure activity relationships studies. the coumarin nucleus possesses some fundamental properties that ensure it an advisable role in the design of new biologically active derivatives, mainly due to its stability, low molecular weight and to the easiness to decorate it for increasing pharmacodynamic and pharmacokinetic properties. coumarin scaffold has been a valuable source of inspiration in the design of novel biologically active compounds and its role as a starting point is very attractive. this natural core is present in a number of currently available drugs used in the treatment of various diseases. for instance, the use of warfarin, acenocumarol and phenprocoumon in the treatment and prevention of thromboembolic diseases is now well established. other examples include the use of hymecromone as choleretic agent and that of the antihelminthic haloxon in veterinary medicine. even though the coumarin nucleus presents an impressive number of biological activities, its presence among marketed drugs is not widespread yet. further efforts are needed in order to achieve coumarin-based compounds with appreciable pharmacokinetic properties, along with high efficacy and a low toxicity profile. moreover, in this review we discussed coumarin photoproperties and their applications as photocleavable protecting groups and fluorescent probes. finally, we analyzed the latest updates in coumarin synthesis from both chemical and technological points of view. one of the most interesting approaches that emerged from this study is the design and use of coumarin-containing hybrid compounds. it is our hope that this review will contribute to further development in the investigation and exploitation of coumarins' potential. author contributions: conceptualization, a.p.; original draft preparation, f.a. and c.p.; writing-review and editing, s.d., a.p. and l.t.; supervision, a.p. and l.t. all authors have read and agreed to the published version of the manuscript. simple coumarins and analogues in medicinal chemistry: occurrence, synthesis and biological activity pharmacological and biochemical actions of simple coumarins: natural products with therapeutic potential coumarin compounds in medicinal chemistry: some important examples from the last year recent advances and therapeutic journey of coumarins: current status and perspectives nomenclature of organic chemistry pharmacological and nutritional effects of natural coumarins and their structure-activity relationships coumarin: a natural, privileged and versatile scaffold for bioactive compounds natural products as fungicide and their role in crop protection sustainable production 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formulation and the identification of an alternative route of coumarin metabolism in humans coumarin derivatives and oxidative stress potential genotoxicity of chronically elevated nitric oxide dna lesions, inducible dna repair and cell division: three key factors in mutagenesis and carcinogenesis oxidative stress: diagnosis, prevention and therapy food antioxidants: chemical insights at the molecular level synthesis and characterization of novel bis-(4-methylcoumarin) derivatives as photosensitizers in antimicrobial photodynamic therapy on the primary and secondary antioxidant activity from hydroxy-methylcoumarins: experimental and theoretical studies investigation of the influence of hydroxy groups on the radical scavenging ability of polyphenols antioxidant activity of fraxetin and its regeneration in aqueous media. a density functional theory study theoretical study on the peroxyl radicals scavenging activity of esculetin and its regeneration in aqueous solution computational study on the antioxidant property of coumarin-fused coumarins coumarin-fused coumarin: antioxidant story from n,n -dimethylamino and hydroxyl groups significantly enhanced antioxidant activity of chitosan through chemical modification with coumarins the evaluation of antioxidant and antifungal properties of 6-amino-6-deoxychitosan in vitro synthesis and biological evaluation of novel coumarins with tert-butyl and terpene substituents the hallmarks of cancer discovering the structure-activity relationships of different o-prenylated coumarin derivatives as effective anticancer agents in human cervical cancer cells primers on molecular pathways lipoxygenases: their role as an oncogenic pathway in pancreatic cancer overexpression of 12/15-lipoxygenase, an ortholog of human 15-lipoxygenase-1, in the prostate tumors of tramp mice synthesis and sar studies of mono o-prenylated coumarins as potent 15-lipoxygenase inhibitors 5-farnesyloxycoumarin: a potent 15-lox-1 inhibitor, prevents prostate cancer cell growth kaseb-mojaver, n. 8-farnesyloxycoumarin induces apoptosis in pc-3 prostate cancer cells by inhibition of 15-lipoxygenase-1 enzymatic activity synthesis, in vitro cytotoxicity activity against the human cervix carcinoma cell line and in silico computational predictions of new 4-arylamino-3-nitrocoumarin analogues synthesis and antiproliferative activity of 3-and 7-styrylcoumarins styrylcoumarin 7-sc2 induces apoptosis in sw480 human colon adenocarcinoma cells and inhibits azoxymethane-induced aberrant crypt foci formation in balb/c mice synthesis and in vitro anticancer activities of diethylene glycol tethered isatin-1,2,3-triazole-coumarin hybrids pyrimidine derivatives as novel lsd1 inhibitors design, synthesis, cytotoxicity and mechanism of novel dihydroartemisinin-coumarin hybrids as potential anti-cancer agents triazole tethered isatin-coumarin based molecular hybrids as novel antitubulin agents: design, synthesis, biological investigation and docking studies azide-alkyne cycloaddition towards 1h-1,2,3-triazole-tethered gatifloxacin and isatin conjugates: design, synthesis and in vitro anti-mycobacterial evaluation discovery of fluorescent coumarin-benzo[b]thiophene 1, 1-dioxide conjugates as mitochondria-targeting antitumor stat3 inhibitors signal transducer and activator of transcription-3, inflammation and cancer: how intimate is the relationship? carbonic anhydrases: novel therapeutic applications for inhibitors and activators multiple binding modes of inhibitors to carbonic anhydrases: how to design specific drugs targeting 15 different isoforms? anhydrase inhibition and the management of glaucoma: a literature inhibition and the management of glaucoma: a literature antiglaucoma carbonic anhydrase inhibitors: a patent review anticonvulsant/antiepileptic carbonic anhydrase inhibitors: a patent review targeting tumour hypoxia: suppression of breast tumor growth and metastasis by novel carbonic anhydrase ix inhibitors interfering with ph regulation in tumours as a therapeutic strategy non-zinc mediated inhibition of carbonic anhydrases: coumarins are a new class of suicide inhibitors deciphering the mechanism of carbonic anhydrase inhibition with coumarins and thiocoumarins 7,8-disubstituted-but not 6,7-disubstituted coumarins selectively inhibit the transmembrane, tumor-associated carbonic anhydrase isoforms ix and xii over the cytosolic ones i and ii in the low nanomolar/subnanomolar range glycosyl coumarin carbonic anhydrase ix and xii inhibitors strongly attenuate the growth of primary breast tumors thioxocoumarins show an alternative carbonic anhydrase inhibition mechanism compared to coumarins inhibitory effects and structural insights for a novel series of coumarin-based compounds that selectively target human ca ix and ca xii carbonic anhydrases coumarins from magydaris pastinacea as inhibitors of the tumour-associated carbonic anhydrases ix and xii: isolation, biological studies and in silico evaluation novel 8-substituted coumarins that selectively inhibit human carbonic anhydrase ix and xii sulfocoumarins as dual inhibitors of human carbonic anhydrase isoforms ix/xii and of human thioredoxin reductase synthesis, biological activity and multiscale molecular modeling studies of bis-coumarins as selective carbonic anhydrase ix and xii inhibitors with effective cytotoxicity against hepatocellular carcinoma synthesis and biological evaluation of coumarin-1,3,4-oxadiazole hybrids as selective carbonic anhydrase ix and xii inhibitors new antibiotics for bad bugs: where are we? antibacterial drug discovery in the resistance era plant products as antimicrobial agents antibacterial activity of coumarins synthesis of novel coumarin appended bis(formylpyrazole) derivatives: studies on their antimicrobial and antioxidant activities unexpected synthesis of bis-coumarin derivatives as potent anti-bacterial and anti-inflammatory agents federal funding for the study of antimicrobial resistance in nosocomial pathogens: no eskape 4-dihydropyrimidinone-coumarin analogues as a new class of selective agent against s. aureus: synthesis, biological evaluation and molecular modelling study microwave-assisted synthesis, computational studies and antibacterial/ anti-inflammatory activities of compounds based on coumarin-pyrazole hybrid bioassay techniques for drug develompent modulation of the antibiotic activity against multidrug resistant strains of coumarins isolated from rutaceae species isolation and antimicrobial activity of coumarin derivatives from fruits of peucedanum luxurians tamamsch novel coumarin-pyrazole carboxamide derivatives as potential topoisomerase ii inhibitors: design, synthesis and antibacterial activity hidden killers: human fungal infections gaffi fungal disease frequency|gaffi-global action fund for fungal infections how common are fungal diseases?-fungal infection trust nosocomial bloodstream infections in us hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study epidemiology of invasive candidiasis: a persistent public health problem synthesis and evaluation of a class of new coumarin triazole derivatives as potential antimicrobial agents 1,2,3-triazole incorporated coumarin derivatives as potential antifungal and antioxidant agents facile synthesis of novel coumarin derivatives, antimicrobial analysis, enzyme assay, docking study, admet prediction and toxicity study antifungal activity, mode of action variability and subcellular distribution of coumarin-based antifungal azoles antimicrobial activity of rhizomes of ferulago trachycarpa boiss. and bioguided isolation of active coumarin constituents coumarins reduce biofilm formation and the virulence of escherichia coli o157:h7 coumarin: a novel player in microbial quorum sensing and biofilm formation inhibition activity of coumarin against candida albicans biofilms susceptibility tests: diffusion test procedures microwave-assisted synthesis, biological evaluation and molecular docking studies of new coumarin-based 1,2,3-triazoles covid-19) events as they happen coumarin: an emerging antiviral agent. heliyon 2020, 6, e03217 plant derived antivirals: a potential source of drug development anti-viral activity of compounds from agrimonia pilosa and galla rhois extract mixture evaluation of antiviral effect and toxicity of total flavonoids extracted from robinia pseudoacacia cv. idaho in vitro and in silico study to evaluate the effectiveness of quercitrin as antiviral drug to dengue virus dehydrojuncusol, a natural phenanthrene compound extracted from juncus maritimus, is a new inhibitor of hepatitis c virus rna replication antiviral activity of resveratrol therapeutic potential of coumarins as antiviral agents bioactive prenylated coumarins as potential anti-inflammatory and anti-hiv agents from clausena lenis bioactive monoterpene indole alkaloids from nauclea officinalis novel tetrahydrofuran derivatives from trigonostemon howii with their potential anti-hiv-1 activities prenylated coumarins from the fruits of manilkara zapota with potential anti-inflammatory effects and anti-hiv activities evaluation of novel n -(3-hydroxybenzoyl)-2-oxo-2h-chromene-3-carbohydrazide derivatives as potential hiv-1 integrase inhibitors three new structures of the core domain of hiv-1 integrase: an active site that binds magnesium design and discovery of hiv-1 integrase inhibitors hydrazide-containing inhibitors of hiv-1 integrase chromone and chromanone derivatives as strand transfer inhibitors of hiv-1 integrase strand transfer inhibitors of hiv-1 integrase: bringing in a new era of antiretroviral therapy who -up to 650 000 people die of respiratory diseases linked to seasonal flu each year influenza pandemics of the 20th century new thiazolyl-coumarin hybrids: design, synthesis, characterization, x-ray crystal structure, antibacterial and antiviral evaluation synthesis and antimicrobial properties of some new thiazolyl coumarin derivatives synthesis, antimicrobial activity and advances in structure-activity relationships (sars) of novel tri-substituted thiazole derivatives bis coumarinyl bis triazolothiadiazinyl ethane derivatives: synthesis, antiviral activity evaluation and molecular docking studies regioselective ibx-mediated synthesis of coumarin derivatives with antioxidant and anti-influenza activities synthesis and structure-activity relationships of imidazole-coumarin conjugates against hepatitis c virus anti-hepatitis b virus activity of esculetin from microsorium fortunei in vitro and in vivo risposta del tessuto al danno origin and physiological roles of inflammation inflammation and the mechanism of action of anti-inflammatory drugs clinical perspectives of anti-inflammatory therapy in the elderly: the lipoxigenase (lox)/cycloxigenase (cox) inhibition concept cyclooxygenase-2 inhibitors: a painful lesson duration of treatment with nonsteroidal anti-inflammatory drugs and impact on risk of death and recurrent myocardial infarction in patients with prior myocardial infarction: a nationwide cohort study thiazole analogues of the nsaid indomethacin as selective cox-2 inhibitors synthesis, in vitro antiproliferative activity and in silico studies of fused tricyclic coumarin sulfonate derivatives molecular modeling, synthesis and screening of some new 4-thiazolidinone derivatives with promising selective cox-2 inhibitory activity synthesis and pharmacological evaluation of n-substituted 2-(2-oxo-2h-chromen-4-yloxy)propanamide as cyclooxygenase inhibitors synthesis and antiinflammatory activity of coumarin derivatives new coumarin derivatives as potent selective cox-2 inhibitors: synthesis, anti-inflammatory, qsar and molecular modeling studies 5-lipoxygenase development of 5-lipoxygenase inhibitors-lessons from cellular enzyme regulation synthesis, anti-inflammatory, analgesic, 5-lipoxygenase (5-lox) inhibition activities and molecular docking study of 7-substituted coumarin derivatives anti-inflammatory prenylated phenylpropenols and coumarin derivatives from murraya exotica the nf-κb signaling pathway in human genetic diseases phosphorilation meets ubiquitination: the control of nf-kb activity the in vitro and in vivo anti-inflammatory effect of osthole, the major natural coumarin from cnidium monnieri (l.) cuss, via the blocking of the activation of the nf-κb and mapk/p38 pathways anti-inflammatory effect of novel 7-substituted coumarin derivatives through inhibition of nf-κb signaling pathway alzheimer's disease: overview the cholinergic hypothesis of geriatric memory dysfunction butyrylcholinesterase inhibitors ameliorate cognitive dysfunction induced by amyloid-β peptide in mice mechanisms of disease: alzheimer's disease the b-secretase enzyme bace1 as a therapeutic target for alzheimer's disease antioxidant and anticholinesterase potential of ferulago cassia with farther bio-guided isolation of active coumarin constituents a new and rapid colorimetric determination of acetylcholinesterase activity novel tacrine-coumarin hybrids linked to 1,2,3-triazole as anti-alzheimer's compounds: in vitro and in vivo biological evaluation and docking study coumarins as cholinesterase inhibitors: a review novel tacrine-1,2,3-triazole hybrids: in vitro, in vivo biological evaluation and docking study of cholinesterase inhibitors design, synthesis and anti-alzheimer's activity of novel 1,2,3-triazole-chromenone carboxamide derivatives novel coumarin-3-carboxamides bearing n-benzylpiperidine moiety as potent acetylcholinesterase inhibitors multifunctional iminochromene-2h-carboxamide derivatives containing different aminomethylene triazole with bace1 inhibitory, neuroprotective and metal chelating properties targeting alzheimer's disease discovery of novel dual-active 3-(4-(dimethylamino)phenyl)-7-aminoalcoxy-coumarin as potent and selective acetylcholinesterase inhibitor and antioxidant synthesis and biological evaluation of 3-arylcoumarins as potential anti-alzheimer's disease agents dual inhibitors of cholinesterases and monoamine oxidases for alzheimer's disease synthesis and evaluation of 7-substituted coumarin derivatives as multimodal monoamine oxidase-b and cholinesterase inhibitors for the treatment of alzheimer's disease synthesis, characterization, crystal structure and evaluation of four carbazole-coumarin hybrids as multifunctional agents for the treatment of alzheimer's disease free-radical-scavenging effect of carbazole derivatives on aaph-induced hemolysis of human erythrocytes inhibition of beta-amyloid peptide aggregation by multifunctional carbazole-based fluorophores design, synthesis and biological evaluation of d-ring opened galantamine analogs as multifunctional anti-alzheimer agents aurone mannich base derivatives as promising multifunctional agents with acetylcholinesterase inhibition, anti-β-amyloid aggragation and neuroprotective properties for the treatment of alzheimer's disease cellular and molecular basis of epilepsy anticonvulsant profiles of certain new 6-aryl-9-substituted-6 design, synthesis and biological evaluation of new hybrid anticonvulsants derived from n-benzyl-2-(2,5-dioxopyrrolidin-1-yl)propanamide and 2-(2,5-dioxopyrrolidin-1-yl)butanamide derivatives synthesis, molecular modeling studies and anticonvulsant activity of certain (1-(benzyl (aryl) amino) cyclohexyl) methyl esters synthesis and docking study of pyrimidine-triazine hybrids for gaba estimation in animal epilepsy models design, synthesis and docking studies of novel benzopyrone derivatives as anticonvulsants design and synthesis of novel parabanic acid derivatives as anticonvulsants synthesis and pharmacological screening of pyridazinone hybrids as anticonvulsant agents design, synthesis, in vivo and in silico evaluation of new coumarin-1,2,4-oxadiazole hybrids as anticonvulsant agents -arylthiazol-4-yl)methyl]azoles as a new class of anticonvulsants: design, synthesis, in vivo screening and in silico drug-like properties new gaba-modulating 1,2,4-oxadiazole derivatives and their anticonvulsant activity design, synthesis and pharmacological evaluation of novel 2-[2-(2-chlorophenoxy) phenyl]-1,3,4-oxadiazole derivatives as benzodiazepine receptor agonists design, synthesis, pharmacological evaluation and docking study of new acridone-based 1,2,4-oxadiazoles as potential anticonvulsant agents anticonvulsant effect of satureja hortensis aerial parts extracts in mice synthesis and anticonvulsant activity of n-substituted 4-amino-3-nitrocoumarins pharmacogenetics of warfarin: current status and future challenges the future prospects of pharmacogenetics in oral anticoagulation therapy almost 60 years old and still causing problems acenocoumarol in thromoembolic disorders current and emerging direct oral anticoagulants: state-of-the-art current and emerging pharmacotherapy for ischemic stroke prevention in patients with atrial fibrillation tecarfarin, a novel vitamin k reductase antagonist, is not affected by cyp2c9 and cyp3a4 inhibition following concomitant administration of fluconazole in healthy participants pharmacokinetics and pharmacodynamics of tecarfarin, a novel vitamin k antagonist oral anticoagulant pharmacokinetics of tecarfarin and warfarin in patients with severe chronic kidney disease synthesis and in vivo evaluation of new coumarin conjugates as potential indirect-action anticoagulants synthesis and biological evaluation of c-3 aliphatic coumarins as vitamin k antagonists synthesis and structure-activity relationships of novel warfarin derivatives pharmacogenomics of 4-hydroxycoumarin anticoagulants coumarin derivatives from ainsliaea fragrans and their anticoagulant activity world health organization (who) a new oral therapy for diabetes management: alpha-glucosidase inhibition with acarbose use of the alpha-glucosidase inhibitor acarbose in patients with 'middleton syndrome': normal gastric anatomy but with accelerated gastric emptying causing postprandial reactive hypoglycemia and diarrhea synthesis and kinetics studies of n -(2-(3,5-disubstituted-4h-1,2,4-triazol-4-yl)acetyl)-6/7/8-substituted-2-oxo-2h-chromen-3-carbohydrazide derivatives as potent antidiabetic agents pharmacological significance of triazole scaffold 1,2,4-triazole: a review of pharmacological activities synthesis, spectroscopic characterization, reactive properties by dft calculations, molecular dynamics simulations and biological evaluation of schiff bases tethered 1,2,4-triazole and pyrazole rings synthetic heterocyclic candidates as promising α-glucosidase inhibitors: an overview synthesis, α-glucosidase inhibition and molecular docking study of coumarin based derivatives syntheses of new 3-thiazolyl coumarin derivatives, in vitro α-glucosidase inhibitory activity and molecular modeling studies synthesis and biological evaluation of 3-arylcoumarin derivatives as potential anti-diabetic agents biscoumarin-1,2,3-triazole hybrids as novel anti-diabetic agents: design, synthesis, in vitro α-glucosidase inhibition, kinetic and docking studies synthesis, in vitro evaluation and molecular docking studies of novel triazine-triazole derivatives as potential α-glucosidase inhibitors stimulation of insulin secretion by 5-methylcoumarins and its sulfur analogues isolated from clutia lanceolata forssk the in vivo dermal absorption and metabolism of [4-14c]coumarin by rats and by human volunteers under simulated conditions of use in fragrances a new coumarin laser dye 3-(benzothiazol-2-yl)-7-hydroxycoumarin lack of evidence for allergenic properties of coumarin in a fragrance allergy mouse model two novel aggregation-induced emission active coumarin-based schiff bases and their applications in cell imaging an injectable peg-bsa-coumarin-gox hydrogel for fluorescence turn-on glucose detection evaluation of antifungal activities and structure-activity relationships of coumarin derivatives development of green/red-absorbing chromophores based on a coumarin scaffold that are useful as caging groups application of coumarin dyes for organic photoredox catalysis the smart drug delivery system and its clinical potential light-triggered release of photocaged therapeutics-where are we now? photoactivated drug delivery and bioimaging beyond proof of principle light-controlled tools coumarinylmethyl caging groups with redshifted absorption a blue-absorbing photolabile protecting group for in vivo chromatically orthogonal photoactivation water-soluble red-shifted coumarin photocages coumarin-caged polyphosphazenes with a visible-light driven on-demand degradation a ratiometric two-photon probe for quantitative imaging of mitochondrial ph values a sensitive and selective fluorescent coumarin-based probe for detection of hypochlorite ion and its application to cellular imaging a sensitive and selective fluorescent probe for detection of glutathione in the presence of cu 2+ and its application to biological imaging a coumarin-based fluorescent probe for hypochlorite ion detection in environmental water samples and living cells a coumarin based fluorescent probe for rapidly distinguishing of hypochlorite and copper (ii) ion in organisms fluorescence quenching-based mechanism for determination of hypochlorite by coumarin-derived sensors novel coumarin-based fluorescent probe for selective detection of cu(ii) synthesis and application of a highly selective copper ions fluorescent probe based on the coumarin group coumarin based hydrazone as an ict-based fluorescence chemosensor for the detection of cu 2+ ions and the application in hela cells coumarin-based multifunctional chemosensor for arginine/lysine and cu 2+ /al 3+ ions and its cu 2+ complex as colorimetric and fluorescent sensor for biothiols a coumarin-based colorimetric and fluorescent dual probe for palladium(ii) ions that can be used in live cells thioacetalized coumarin-based fluorescent probe for mercury(ii): ratiometric response, high selectivity and successful bioimaging application highly selective on-off fluorescence recognition of fe 3+ based on a coumarin derivative and its application in live-cell imaging a novel fluorescein-coumarin-based fluorescent probe for fluoride ions and its applications in imaging of living cells and zebrafish in vivo a novel coumarin-based fluorescent sensor for ca 2+ and sequential detection of f − and its live cell imaging dicyanovinylcoumarin as a turn-on fluorescent sensor for cyanide ion a near-infrared fluorescent probe for rapid, colorimetric and ratiometric detection of bisulfite in food, serum and living cells a review of sulphites in foods: analytical methodologyand reported findings sulfites in foods: uses, analytical methods, residues, fate, exposure assessment, metabolism, toxicity and hypersensitivity clinical effects of sulphite additives health hazards from volcanic gases: a systematicliterature review estimation of bisulfate in edible plant foods, dog urine and drugs: picomolar level detection and bio-imaging in living organisms research on cruciferous vegetables, indole-3-carbinol and cancer prevention: a tribute to lee w. wattenberg crouciferous vegetables: cancer protective mechanism of glcisunolate hydrolisi products and selenium studies on the mechanism of myrosinase: investigation of the effect of glycosil acceptors on enzyme activity rosen's emergency medicines new insights into the antibacterial activity of hydroxycoumarins against ralstonia solanacearum molecular traits controlling host range and adaptation to plants in ralstonia solanacearum environmental cues controlling the pathogenicity of the plant pathogen ralstonia solanacearum needs aerotaxis for normal biofilm formation and interactions with its tomato host coumarins from the peel of citrus grown in colombia: composition, elicitation and antifungal activity secondary metabolites in plant innate immunity: conserved function of divergent chemicals two classes of plant antibiotics: phytoalexins versus phytoanticipins design, synthesis and antifungal activity evaluation of coumarin-3-carboxamide derivatives synthesis of new coumarin 3-(n-aryl) sulfonamides and their anticancer activity explosive properties of 1-hydroxybenzotriazoles synthesis and antitumor activities of a series of novel quinoxalinhydrazides synthesis, characterization and antibacterial activities of n-[1-(substituted phenyl) ethyl]-2-hydroxybenzohydrazide synthesis, characterization and antifungal activity of coumarin-functionalized chitosan derivatives principles of bioinorganic chemistry synthesis and characterization of a binuclear coumarin-3-carboxylate copper(ii) complex copper(ii) complexes of coumarin-derived schiff base ligands: pro-or antioxidant activity in mcf-7 cells? role of reactive oxygen species (ros) in therapeutics and drug resistance in cancer and bacteria the two faces of reactive oxygen species in cancer oxidative stress and lipid peroxidation products in cancer progression and therapy inhibition of landschutz ascites tumour growth by metal chelates derived from 3,4,7,8-tetramethyl-1,1 0-phenanthroline strong in vitro and vivo cytotoxicity of novel organoplatinum(ii) complexes with quinoline-coumarin derivatives synthesis, crystal structure and investigation of the catalytic and spectroscopic properties of a zn(ii) complex with coumarin-hydrazone ligand non-cytotoxic antibacterial silver-coumarin complex doped sol-gel coatings recent advances in the synthesis of coumarin derivatives via knoevenagel condensation: a review an overview on synthetic strategies to coumarins deciding wether to go with the flow: evaluating the merits of flow reactors for synthesis microreaction technology as a novel approach to drug design, process development and reliability continuous-flow technology-a tool fo the safe manifacturing of active pharmaceutical ingredients two-stage flow synthesis of coumarin via o-acetylation of salicylaldehyde synthesis of coumarin derivative using polymer supported reagents one photocatalyst, n activation modes strategy for cascade catalysis: emulating coumarin biosynthesis with (-)-riboflavin visible-light-driven, photoredox-catalyzed cascade of ortho-hydroxycinnamic esters to access 3-fluoroalkylated coumarins bichromatic photosynthesis of coumarins by uv filter-enabled olefin metathesis solvents and solvent effects in organic chemistry solvent-free coumarin synthesis via pechmann reaction using solid catalysts solvent-free reactions solvent-free coumarin synthesis hetero-annulated coumarins as new ache/buche inhibitors: synthesis and biological evaluation nano-silica sulfuric acid as an efficient catalyst for the synthesis of substituted pyrazoles preparation and characterization of lewis acid grafted sulfonated carbon@titania composites for the multicomponent synthesis of 4h-pyrimido[2,1-b]benzothiazoles and benzoxanthenones under solvent-free conditions a green and convenient approach for the one-pot solvent-free synthesis of coumarins and β-amino carbonyl compounds using lewis acid grafted sulfonated carbon@titania composite ultrasonic accelerated knoevenagel condensation by magnetically recoverable mgfe 2 o 4 nanocatalyst: a rapid and green synthesis of coumarins under solvent-free conditions fe 3 o 4 @boehmite-nh 2 -coii nps: an environment friendly nanocatalyst for solvent free synthesis of coumarin derivatives through pechmann condensation reaction ionic liquids-an overview ionic liquids. green solvents for the future when can ionic liquids be considered readily biodegradable? biodegradation pathways of pyridinium, pyrrolidinium and ammonium-based ionic liquids biodegradation studies of ionic liquids toxicity of ionic liquids: eco(cyto)activity as complicated but unavoidable parameter for task-specific optimization brønsted acidic ionic liquid-catalyzed tandem reaction: an efficient approach towards regioselective synthesis of pyrano[3,2-: c] coumarins under solvent-free conditions bearing lower e-factors novel brønsted acidic ionic liquids and their use as dual solvent-catalysts condensation of 2-naphtol with arylaldehydes using acetic acid functionalized ionic liquids as highly efficient and reusable catalysts tandem knoevenagel-michael-cyclocondensation reactions of malononitrile, various aldehydes and dimedone using acetic acid functionalized ionic liquid synthesis of bis-coumarins over acetic acid functionalized poly(4-vinylpyridinum) bromide (apvpb) as a green and efficient catalyst under solvent-free conditions and their biological activity microwave-assisted organic synthesis-a review dielectric parameters relevant to microwave dielectric heating acceleration of the pechmann reaction by microwave irradiation: application to the preparation of coumarins microwave promoted and improved thermal synthesis of pyranocoumarins and furocoumarins task-specific ionic liquid as reagent and reaction medium for the one-pot horner-wadsworth-emmons-type reaction under microwave irradiation one-pot wittig and knoevenagel reactions in ionic liquid as convenient methods for the synthesis of coumarin derivatives ytterbium triflate promoted coupling of phenols and propiolic acids: synthesis of coumarins microwave-assisted synthesis of xanthones promoted by ytterbium triflate ytterbium triflate catalysed meerwein-ponndorf-verley (mpv) reduction synthesis of coumarin by yb(otf) 3 catalyzed pechmann reaction under the solvent-free conditions synthesis of 7-hydroxy-4-methylcoumarin via the pechmann reaction with amberlyst ion-exchange resins as catalysts coumarin derivatives solvent-free synthesis under microwave irradiation over heterogeneous solid catalysts microwave-assisted synthesis of phenylpropanoids and coumarins: total synthesis of osthol synthesis of indolo[2,3-c]coumarins and indolo[2,3-c]quinolinones via microwave-assisted base-free intramolecular cross dehydrogenative coupling this article is an open access article distributed under the terms and conditions of the creative commons attribution (cc by) license funding: this research received no external funding. the authors declare no conflict of interest. key: cord-004879-pgyzluwp authors: nan title: programmed cell death date: 1994 journal: experientia doi: 10.1007/bf02033112 sha: doc_id: 4879 cord_uid: pgyzluwp nan it is widely held that all developmental cell death is of a single type (apoptosis) and that neuronal death is primarily for adjusting the number of neurons in a population to the size of their target field through competition between equals for target-derived factors. we shall draw on our research and on that of others to criticize these views and replace them by the following. at least three types of neuronal death occur, only one of which resembles apoptosis; a neuron can choose between several self-destruct mechanisms depending on the cause of its death. the purpose of the death is to regulate connectivity, not neuron number. competitors for trophic factors are unequal, and many losers have made axonal targeting errors. a neuron's survival and differentiation depend on multiple anterograde and retrograde signals. activity affects retrograde signals and some but not all anterograde ones. the pattern of activity is more important than the overall amount. in rodents, the period of naturally occuring cell death of motoneurons is followed by a period of supersensitivity to axonal injury. thus, in newborn rodents lesion of the facial nerve leads to a rapid degeneration of the injured motoneurons. we have tested whether overexpression, in rive, of the bcl-2 proto-oncogene was capable of preventing death of axotomized motoneurons. to address this question we used transgenic mice whose motoneurons overexpress the bcl-2 protein. one of the two facial nerves of newborn mice was transected on the 2nd-3rd post-natal day. seven days after the lesion, the morphology of the facial nuclei was analyzed. in control mice, and when compared to the intact nucleus, 70 to 80 % of axotomized motoneurons had disappeared. in contrast, in the transgenic animals, the number of motoneurons on the lesioned side remained unchanged when compared to the eontralateral nucleus. furthermore, their axons remained visible up to the distal lesion site. these experiments show that, in rive, motoneurons overexpressing the bcl-2 protein survive after axotomy, and suggest that, in rive, bcl-2 protect neurons from experimentally induced cell death and could be a target for treatment of motoneurons degenerative diseases. messmer s., mattenberger l., sager y., blatter-garin m-c., pometta d., kate a., james r.w. drpt de mrdeeine, drpt. de pharmacologie, div. de neurophysiologie clinique, facult6 de mrdecine, gen~ve. clusterin is a widely expressed glycoprotein, highly conserved across species. numerous functions have been postulated for this protein. the most important are roles in lipid transport, as elusterin is associated with apolipoprotein ai in hdl, complement regulation and tissue remodelling, in particular during cell death and differentiation. using cultures of rat spinal cord neurones (90% neurons and 5-10% non-neuronal cells), we have studied the expression of clusterin and ape e in glutamate-induced neuronal cell death to examine potential roles in lipid management. up-regulation of the two proteins was observed. clusterin and ape e appear in the conditioned medium respectively 15h and 7.5h after incubation with glutamate. control studies, in the presence of a noncompetitive nmda receptor agonist showed the secretion of clusterin and ape e to be diminished by >60%. no up-regulation of either protein was observed in complementary studies with exclusively non-neuronal cell cultures. the cellular origin of the 2 secreted proteins is presently under investigation. programmed cell death and tissue remodelling are consequences of hormonally induced restructuring of the rat ventral prostate after castration and the rat mammary gland after weaning. we used the "differential display"-method (liang and pardee, 1992, science 257:967) to detect and isolate edna fragments whose corresponding rnas are regulated either coincidentally, or in an organ specific fashion during mammary gland involution and postcastrational prostate regression. partial sequencing of 12 clones revealed high, but not absolute homology of 5 fragments with sequences, previously characterized in different biological contexts. these five encode functions which could be anticipated to be important for cell growth and/or programmed cell death, we are presently investigating the functions of several of these transcripts in cell culture and in rive. antisense oligos are being employed in vivo to determine whether these genes contribute to the phenotype of programmed cell death. b epitopes derived from the envelope gp52 glycoprotein (ep3) or from the viral superantigen of mmtv have been incorporated into inert or live vaccines. the inert vaccine consists of purified chimeric proteins which contain the b epitopes alone or fused to multimeric promiscuous t helper epitopes from tetanus toxin. mice were immunized subcutaneously with these chimeric proteins. the live vaccine consists of an avirulent strain of salmonella typhimurium which expresses the mmtv epitopes in the form of chimeric proteins fused to the nucleocapsid protein of hepatitis b virus. this vaccine is given to mice in one oral dose. the level, duration and isotype of the immune response generated by each vaccine have been measured and compared. the level of protection has been investigated by systemically challenging immunized mice with the relzovims. a reduced binding of oxytocin (ot) occurs with aging in some, but not all, areas of the rat brain (arsenijevic et al., experientia 1993, 49, a75) . the candate putamen showed the most impressive loss of ot receptors. two other regions, the hypothalamic ventromedial nucleus (vmh) and the islands of caueja (icj) had also an important deficit of ot binding sites. on the other hand, these two regions were known to be sensitive to sex steroids. in the present work, we treated from 20 month old rats during one month with testosterone propionate (2 #g/kg s.c., once every 3 days) dissolved in oil. three rats of the same age injected with oil only served as controls. we labelled ot receptors throughout the brain of old rats using a 125i-labelled ligand specific for ot receptors. analysis of autoradiograms by an image analyzer revealed that the testosterone treatment increased ot binding sites in the vmh, in the icj, and, to a lesser extent, in the bed nucleus of the stria terminalis, a region also sensitive to sex steroids, by contrast, in the caudate putamen, the disappearance of ot receptors was not compensated. in conclusion, the decrease of ot receptors occurring in vmh and icj with aging can be reversed by administration of gonadal steroids. in contrast, the loss of ot receptors in the striatum appears to depend on another mecanism. vasopressin (avp) receptors are expressed transiently in the facial nucleus during development (tribollet et el., 1991, dev. brain res., 58, 13-24) . avp may therefore play a role in the maturation of neuromuscular connexions in the neonate rat, and possibly in the restanration of these connexions after nerve lesion in the adult. in order to investigate the latter proposition, we have sectionned the facial nerve in adult rats and used quantitative autoradiography to look at avp binding sites in the facial nucleus at various postoperative times. we observed a massive and transient increase of avp binding sites on the operated side. the number of facial avp binding sites reaches a maximum about one week after nerve section, remains stable during 2-3 weeks, then begin to decrease towards control level. the induction of avp receptors is markedly delayed if the proximal stump of the nerve is ligated. to assess whether other motor nuclei would also react to axotomy by up-regulating the expression of avp receptors, we have sectionned the hypoglossal nerve and the sciatic nerve. in both cases, the binding of avp receptor ligand increases massively in the respective motor nuclei, with a time-course similar to that found in the facial nucleus. altogether, our data suggest that central avp could be involved in the process of nerve regeneration. cytotoxic t-cell mediated apoptosis schaerer,e, karapetian,o.,adrian,m. and tschopp,j. inst.de biochimie, univ.de lausanne, 1066 epalinges. an apoptotic cell death mechanism is used by cytolytic t cells (ctl) to lyse appropriate target cells. ctl harbor cytoplasmic storage compartments, containing the lytic protein perforin and serineproteases (granzymes), whose content is released upon target cell interaction. we show that these granules are multivesieular bodies and that degranulation releases these intragranular vesicles (igv) having granzymes, t-cell receptor and yet undefined proteins associated. isolated igvs and perforin induce dna breakdown in target cells within 20 minutes. microscopic analysis demonstrates that igv specifically interact with target cell via the t-cell receptor and that their contents is taken up by the target cell. already 15 min. after interaction, 3 distinct igv proteins are found in the nucleus of the target cell.one of the molecules has been identified to be granzyme a, previously reported to be involved in apoptosis. we propose that lymphocytes transfer apoptosisinducing proteins to the nucleus of the target cells using vesicles as vehicles for delivery. cytotoxic t cells kill their targets by a mechanism involving membranolysis and dna degradation (apoptosis). recently, two sets of proteins have been proposed as dna breakdown-inducing molecules in t cells: granzyme a, b and tia-i. in this study, we cloned and further characterized the tia-i mouse homologue. aa sequence comparison with the human tia-1 showed an overall identity of 93%. devoid of a signal peptide, tia is yet localized to cytotoxic granules, probably targeted via a gly-tyr-motif. as tia-i, its mouse homolcgue contains three rnabinding domains. expression of tia during development shows a very strong signal in the brain and weaker signals in thymus, heart and other organs. during embryonic development several structures that contribute to organogenesis form transiently and are later eliminated by apoptosis. this pattern of tia expression could indicate its involvement in apoptosis. prostate involution occurs after castration in rats and is associated with the death by apoptosis of a large fraction of the epithelial cells. we have isolated several genes from a prostate involution bacteriophage lambda library using differential screening methods. among these clones, one d~monstrated an especially strong signal when used as a probe against northern blots of prostate mlhna obtained before, and at different times after castration. this gene is down-regulated after castration by 40-fold within 5 days. intramuscular injection of a testosterone depot resulted in complete restoration of expression within 24 hours. upon sequencing it became apparent that this clone has a high degree of homology to a known ndah dehydrogenase encoded in mitochondrial dna. the clone failed to hybridize to any transcripts from rat organs other than prostate. we are now in the process of isolating the htm~n hc~olog to this gene for use as a biomarker in study of benign hyperplasia and developing carcinoma. this gene is a possible indicator for testosterone-independent cell populations or of cells lacking ftl~ctional testosterone receptor. during the first three postnatal weeks the rat lung undergoes the last two developmental stages, the phase of alveolarization and the phase of microvascular maturation. the latter involves a decrease of the connective tissue mass in the alveolar septa and a merging of the two capillary layers to a single one. speculating that programmed cell death may play a role during this remodeling, we searched for the presence of apoptotie cells in rat lungs between days 10 and 24. lung paraffin sections were treated with y-terminal transferase, digoxigenin-dutp, and anti-digoxigeninfluorescein-f(ab)-fragments, and the number of fluorescent nuclei was compared between sections at different days. while the number of apoptotie ceils was low until the end of the second week and at day 24, we observed an about eight fold increase of fluorescent nuclei towards the end of the third week. we conclude that programmed cell death is involved in the structural maturation of the lung. brunner, a., wallrapp, ch., pollack, i, twardzik, t. and schneuwly, s. lehrstuhl genetik, biozentrum universit~t w~rzburg, mutants in the giant lens (g/l) gene show a strong disturbance in ommatidial development. in the absence of any gene product, additional phetoreceptors, cone cells and pigment cells develop. opposite effects can be seen in flies in which the gene product of the giant lens gene can be ectopically expressed by heat shock. a second very typical phenotype is the disturbance of photoreceptor axon guidance. molecular analysis of gil shows that it encodes a secreted protein of 444aa containing three evolutionary conserved cystein-motives very similar to egf-like repeats. we propose that gil functions as a secreted signal, most likely a lateral inhibitor for the development of specific cell fates and that gil, either directly or indirectly, is involved in targeting photoreceptor axons into the brain. the decrease in cellularity during scar establishment is mediated through apoptosis desmouliere, a., redard, m., darby, i., and g. gabbiani department of pathology, cmu, 1 rue michel server, 1211 gen~ve 4 dudng the healing of an open wound, granulation tissue formation is characterized by replication and accumulation of fibroblastic cells, many of which acquire morphological and biochemical features of smooth muscle cells and have been named myofibroblasts (sch0rch et el., histology for pathologists, t992). as the wound evolves into a scar, there is an important decrease in ceuuladty, including disappearance of myofibroblasts. the question adses as to which process is responsible for myofibroblast disappearance. during a previous investigation on the expression of (z-smooth muscle actin in myofibroblasts, we have obsewed that in late phases of wound healing, many of myofibroblasts show signs of apoptosis end suggested that this type of cell death is responsible for the disappearance of myofibroblasts (darby et al., lab. invest. 63:21, 1990) . we have tested this hypothesis by means of electron microscopy and morphometry and by in situ end-labeling of fragmented dna (wijsman et al., j. histochem. cytochem. 41:7, t 993) . our results show that the number of apoptotic cells increases as the wound closes and suggest that this may be the mechanism for the disappearance of myofibroblasts as well as for the evolution of granulation tissue into a scar. (supported by the swiss national science foundation, grant n~ s01-16 r. jaggl, a. marti and b. jehn. universit~t bern, akef, tiefenaustr. 120, 3004 bern at weaning the mammary gland undergoes a reductive remodelling process (involution) which is associated with the cessation of milk protein gene expression and apoptosis of milk-produclng epithelial cells. this process can be reversed by returning the pups to the mother within 1 day. elevated nuclear protein kinase a (pka) activity was observed from one day post-lactation, paralleled by increased c-los, junb, ]und and to a lesser extent c-]un mrna levels. ap-1 dna binding activity was transiently induced and the ap-1 complex was shown to consist principally of cfos/jund. oct-1 dna binding activity and oct-1 protein were gradually lost from the gland over the first four days of involution, whereas oct-1 m_rna levels remained unchanged. comparing nuclear extracts from normal mammary glands with nuclear extracts from glands which had been cleared of all epithelial cells three weeks after birth revealed that pka activation, ap-1 induction and oct-1 inactivation are all dependent on the presence of the epithelial compartment. the increased fos/jtm expression and the inactivation of oct-1 may be consequences of the increased pka activity. when involution is reversed, both, pica activity and ap-1 dna binding activity (and fos andjun mrna levels) are reduced to basal levels. our data suggests a role for pka and ap-1 on progranlmed cell death of manlnmry epithelial ceils. bcl-2~ does not require membrane attachment for its survival activity c. borner*, i. martinout, c. mattmann*, m. irmler*, e. sch&rrer*, j.-c. martinou-j-, and j. tschopp*. * institute of biochemistry, university of lausanne, 1066 epalinges, 1 institute of molecular biology, glaxo inc.,1228 plan los ouates. 8cl-2(z is a mitochondrial or perinuclear-associated oncoprotein that prolongs the life span of a variety of cell types by interfering with programmed cell death. how it exerts this activity is unknown but it is believed that membrane attachment is required. to identify critical regions in bcl-2o~ for subcellular localization and survival activity, we created by site-directed mutagenesis, various mutations in regions which are most conserved between the different bcl-2 species. we show here that membrane attachment is not required for the survival activity of bcl-2o< a truncation mutant of bcl-2(z lacking the last 33 amino acids (t3) including the hydrophobic domain is soluble, yet fully active in blocking apoptosis of sympathetic neurons induced by ngf deprivation or l929 fibroblasts induced by tnfc~ treatment. we further provide evidence for a putative functional region in bcl-2 which lies in the conserved domains 4 and 5 upstream of the hydrophobic cooh terminal tail. the breakdown of nuclear dna is considered to be a hallmark of apoptosis. we previously identified the perinuclear membrane localized dnase i as the endonuclease involved in the formation of oligonucleosomal-sized fragments (dna ladder). it is not clear how the nuclease is activated and has access to the dna. we show that in thymocytes induced to undergo apoptosis, lamin breakdown preceded dna laddering. by transfeeting hela cells with a constitutively active cdc2 mutant, nuclear envelope breakdown and typical apoptotic features (ehromatin condensation) were observed. moreover, co-transfection with cdc2 mutant and dnase i led to dna degradation. we propose that apoptosis can be induced by wrongly timed and hence abortive mitosis leading to uncontrolled nuclear membrane disintegration. s02-01 s02-04 platelet-derived growth factor (pdgf) is thought to play an active role in fibrosing diseases. bronchiolitis obliterans-organizing pneumonia (boop) is a condition characterized by intraluminal proliferation of connective tissue inside distal air spaces. to evaluate pdgf expression in boop we performed immunohistoehemistry on lung biopsies from 20 patients and 10 controls free of fibrosis. sedal sections were stained with an antibody against either pdgf or the monoeyte/macrophage marker cd68, in both groups the pdgf ~9 cells were essentially tissue macrophages. using point counting to measure volume fraction (vv) , pdgf-pesitive cells represented 4.65+1.63% (mean+sd) of the volume occupied by lung tissue in the boop cases, and 2,12+0.65% in the controls (!0<0,001). similarily, 10.73+4.69% of the lung tissue was occupied by cd68 e~ macrophages in the boop cases, compared to 5.37:~3.73% in the controls (p