Molecular docking analysis on the interaction between bovine serum albumin and three commercial fluoroquinolones: Ciprofloxacin, enrofloxacin and pefloxacin European Journal of Chemistry 12 (2) (2021) 192-196 European Journal of Chemistry ISSN 2153-2249 (Print) / ISSN 2153-2257 (Online) – Copyright © 2021 The Authors – Atlanta Publishing House LLC – Printed in the USA. This work is published and licensed by Atlanta Publishing House LLC – CC BY NC – Some Rights Reserved. https://dx.doi.org/10.5155/eurjchem.12.2.192-196.2103 European Journal of Chemistry View Journal Online View Article Online Molecular docking analysis on the interaction between bovine serum albumin and three commercial fluoroquinolones: Ciprofloxacin, enrofloxacin and pefloxacin Otávio Augusto Chaves * and Leonardo Vazquez Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, 21040-900, Brazil otavio.chaves@ioc.fiocruz.br (O.A.C.), leonardo_vazquez@hotmail.com (L.V.) * Corresponding author at: Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, 21040-900, Brazil. e-mail: otavio.chaves@ioc.fiocruz.br (O.A. Chaves). 10.5155/eurjchem.12.2.192-196.2103 Received: 31 January 2021 Received in revised form: 14 March 2021 Accepted: 28 March 2021 Published online: 30 June 2021 Printed: 30 June 2021 Fluoroquinolones are a family of broad spectrum, systemic antibacterial agents that have been used as therapy for infections in the respiratory and alimentary tract in animals. The pharmacodynamic of this class is widely described, predominantly to the commercial drugs ciprofloxacin (CIP), enrofloxacin (ENR), and pefloxacin (PEF). Bovine serum albumin (BSA) is the main endogenous carrier in the bovine bloodstream, being responsible for the biodistribution of different classes of molecules and drugs, including fluoroquinolones. The molecular features and interaction between BSA and fluoroquinolones are not fully described, thus, the present work enlightens the intimacy of the interaction of BSA with CIP, ENR, PEF through structural modeling and molecular docking calculation approaches. The role of key amino acid residues was assessed, indicating that the main protein binding pocket is composed by Trp-212 residue playing an important stabilization for the three fluoroquinolones through both hydrogen bonding and van der Waals forces, where reside the individual structural differences observed among the three fluoroquinolones and BSA. There is a descriptive protagonism of carboxyl group on the ENR interaction which traps the molecule and avoids the deep communication in the protein binding pocket, as well as the ligands CIP and PEF showed an interface amino acid residue interaction profile higher than 70%. Pefloxacin Enrofloxacin Ciprofloxacin Molecular docking Veterinary science Bovine serum albumin Cite this: Eur. J. Chem. 2021, 12(2), 192-196 Journal website: www.eurjchem.com 1. Introduction The fluoroquinolones are a drug class that targets the bacterial DNA gyrase and topoisomerase IV varying the efficiency between low and high concentrations [1]. The fluoro- quinolones are extensively used for the treatment of sick animals by bacteria, whether in the rapid growth or stationary microorganism phase [2]. Due to the uncontrolled used of some fluoroquinolones, not only as antibacterial agents but also as growth promoters and prophylactic agents in lactating animals, it has been detecting the presence of fluoroquinolones in commercial milk, being a problem for human health [3-5]. The ciprofloxacin (1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl) -1,4-dihydroquinoline-3-carboxylic acid, Figure 1A), enroflo- xacin (1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-4-oxo- 1,4-dihydroquinoline-3-carboxylic acid, Figure 1B) and peflo- xacin (1-ethyl-6-fluoro-7-(4-methylpiperazin-1-yl)-4-oxo-1,4- dihydroquinoline-3-carboxylic acid, Figure 1C) are one of the most common synthetic fluoroquinolones widely used as anti- microbial agents [6]. The CIP, ENR, and PEF are characterized by two pKa values, e.g., pK1 = 6.16 and pK2 = 8.63 for CIP [7], pK1 = 6.00 and pK2 = 8.72 for ENR [8] and pK1 = 6.30 and pK2 = 7.60 for PEF [9], showing their internal versatile structural change according to the pH of the different biological medium. In terms of infections in the respiratory and alimentary tracts, generally the fluoroquinolones are administered in veterinary medicine via subcutaneous in cattle, or even intra- muscular administration to pigs and orally to turkeys and chickens [10]. Particularly, the ENR injection is the main veterinary conduct for use in the treatment of bovine respira- tory illness caused by susceptible microorganisms, including Mannheimia (Pasteurella) haemolytica, Histophilus somni and Pasteurella multocida [11,12]. Alternatively, the available biological assay data of CIP for the treatment of acute mastitis in dairy cows showed a rate of 86.0% of success, compared with 72.0% of the control penicillin-streptomycin [13]. In its turn, the PEF performance showed substantial activity against gram- negative bacteria including Aeromonas hydrophila, Capnocyto- phaga, Haemophilus, Neisseria, and Legionella, however, PEF is less active than CIP towards Pseudomonas aeruginosa [14]. In cattle, has already been described the detection of ENR + CIP deposit, being detected in about 65.0%, 80.0%, 88.0%, and 50.0% in liver, kidney, muscle, and fat, respectively [5]. ABSTRACT RESEARCH ARTICLE KEYWORDS https://dx.doi.org/10.5155/eurjchem.12.2.192-196.2103 https://www.eurjchem.com/ https://dx.doi.org/10.5155/eurjchem.12.2.192-196.2103 mailto:otavio.chaves@ioc.fiocruz.br mailto:leonardo_vazquez@hotmail.com mailto:otavio.chaves@ioc.fiocruz.br http://www.eurjchem.com/ https://crossmark.crossref.org/dialog/?doi=10.5155/eurjchem.12.2.192-196.2103&domain=pdf&date_stamp=2021-06-30 Chaves and Vazquez / European Journal of Chemistry 12 (2) (2021) 192-196 193 2021 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.12.2.192-196.2103 Figure 1. The chemical structure of the three fluoroquinolones under study: ciprofloxacin (CIP), enrofloxacin (ENR), and pefloxacin (PEF). The pharmacokinetics of this class is mainly driven by serum albumin (SA), which is the most abundant protein present in the circulatory system, being about 60% of the total plasma proteins [15]. Its main function is associated with the distribution and excretion of several endogenous and exoge- nous compounds, e.g., fatty acids, bilirubin, prostaglandins, steroids, cholesterol, hormones, vitamins, and drugs [16]. In this case, bovine serum albumin (BSA) is the main transporting protein synthesized in the cattle liver and also the most representative globular protein for preliminary pharma- cokinetic studies. [17]. From a structural point of view, BSA is a single-chain composed of 583 amino acid residues, having 20 tyrosine and 2 tryptophan residues (Trp-134 and Trp-212) which play an important role in the interaction with endo- genous and exogenous compounds. The secondary structure of BSA consists of nine loops held together by 17 disulfide bonds, resulting in tertiary structure of three domains (I, II, and III) separated into two subdomains (A and B). These disulfide bonds carry a rigidity to the helices, but at the same time allow sufficient flexibility for the protein to suffer conformational changes based on the experimental conditions [6]. Due to a large number of negative charged (Glu and Asp) and positively charged (Lys and Arg) residues, BSA is highly soluble in aqueous media [17]. Extensive investigations on the interaction between commercial drugs with SA have been reported [18-20]. Since SA assists as the main transport carrier of drugs and plays a prevailing role on their bioavailability, having a significant impact on the pharmacokinetics of drugs, the profound study of the behavior on the relationship between albumin and drugs is particularly important, affecting the effectiveness of pharma- ceutical agents [21]. Despite the numerous reports of the thera- peutic importance of CIP, ENR, and PEF on the treatment of diverse animal illness, the specialized literature reports a spectroscopic analysis on the understanding of the interactions between albumin: CIP/ENR/PEF [6,22-31]. In silico approach via molecular docking calculations is a very effective tool which explores at both molecular and atomic levels the behavior on the ability to estimate the participation of specific chemical groups and their interactions in complex stabilization. The lack of this kind of data for the three cited fluoroquinolones drove the work to fill this blank. Thus, to complement the studies of biodistribution of CIP, ENR and PEF in the bovine blood plasma, molecular docking calculations under physiological conditions (pH = 7.4) were carried. For the present study, we were chosen CIP/ENR/PEF as three representative commercial fluoro- quinolones, due to their high importance and wide application in veterinary medicine. 2. Experimental 2.1. Molecular descriptor calculation The crystallographic structure of BSA was obtained from the Protein Data Bank (PDB) with access code 4F5S [32]. This structure has a resolution of 2.47 Å. The CIP, ENR, and PEF structures were built and energy minimized at physiological pH (pH = 7.40) with the Density Functional Theory (DFT) method B3LYP/6-31G* available at the Spartan’14 software (Wavefunction, Inc.). The molecular docking was performed with the GOLD 5.6 software (Cambridge Crystallographic Data Centre - CCDC). The crystallographic hydration molecules were deleted and hydrogen atoms were added to the protein according to the data inferred by GOLD 5.6 software on the ionization and tautomeric states [33]. To evaluate the best scoring function that will be used in the molecular docking run (ChemPLP, GoldScore, ChemScore, or ASP), redocking study was carried out with the crystallographic ligand naproxen inside BSA binding pocket (Trp-212-containing binding site – PDB code: 4OR0) [34]. The Root Mean Square Deviation (RMSD) obtained for ChemPLP, GoldScore, ChemScore, and ASP was 0.512, 1.103, 0.811, and 1.415, respectively. Since ChemPLP function provided the lowest RMSD value, there is a clear indication that this scoring function is the best choice to be applied in the molecular docking studies for the three fluoro- quinolones. The data available from literature by spectroscopic assays (fluorescence quenching studies) described that CIP, ENR and PEF interact with BSA possibly bound next to one of the internal tryptophans (Trp-134 or Trp-212) [6,22-31]. From this data, to identify the main binding site of BSA, it was defined 10 Å spherical radius around each tryptophan residue to molecular docking calculations. The docking score of each pose was obtained through the sum of a series of energy terms involved in the protein-ligand interaction process, so a more positive score indicates a better interaction [35]. The number of genetic operations (crossover, migration, mutation) in each docking run used in the searching procedure was set to 100,000. It was used Student’s t-test to determine statistical significance between the data obtained for the two binding sites. The figures of the docking poses with the highest docking score value were generated with the PyMOL Delano Scientific LLC software [36]. Additionally, in order to verify the frequency calculation, the molecular docking calculations were carried out three times selecting the same binding region and using the same spherical radius. In all cases, the best docking pose was obtained to the same site of the albumin structure, as well as the ligand assumed a quite similar docking pose. 3. Results and discussion The BSA structure is didactically divided in three homo- logous helical domains: I (1-179), II (180-384), and III (385- 583), which show different binding abilities toward small molecules [19,21,32,37]. Is shown in Figure 2, the BSA structure presenting two internal tryptophan residues: Trp-134 located in domain I (generally known as site III) and Trp-212 located in the domain II (generally known as site I) [32,35]. From the literature it is known that the fluoroquinolones CIP, ENR and PEF are able to quench the BSA intrinsic fluorescence, indicating that probably these ligands might be bound next one of the two tryptophan residues [22-31]. 194 Chaves and Vazquez / European Journal of Chemistry 12 (2) (2021) 192-196 2021 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.12.2.192-196.2103 Table 1. Fitness scores (dimensionless) for the best docking poses in the Trp-134- and Trp-212-containing binding sites for BSA: CIP, BSA: ENR, and BSA: PEF (ChemPLP function). BSA:CIP BSA:ENR BSA:PEF Trp-134 Trp-212 Trp-134 Trp-212 Trp-134 Trp-212 42.61 48.87 34.49 49.36 43.93 49.32 43.14 53.99 35.98 45.14 39.64 49.72 40.26 52.96 39.46 49.97 42.99 46.85 40.24 44.88 39.87 40.07 37.27 45.57 44.13 43.32 44.71 40.19 48.59 50.33 44.12 53.50 39.56 50.00 43.01 45.54 42.42* 49.59 * 39.01* 45.79 * 42.57 * 47.89 * * Docking score average value. Figure 2. Crystallographic BSA structure (PDB: 4F5S) highlighted the three domains: I (yellow), II (beige), and III (orange). The internal tryptophan residues were represented as green spheres and hydration molecules are represented as red dots. In addition, the experimental number of binding sites (n ~ 1.00) indicate that each fluoroquinolone interacts in the ratio of 1:1, suggesting just one main binding site in the BSA structure for CIP, ENR or PEF [22-30]. From these experimental parameters, the molecular docking calculations were carried out for BSA: CIP, BSA: ENR and BSA: PEF in the Trp-134 and Trp-212-containing binding sites. The approach used was to split the protein into multiple binding sites and carry out individual docking experiments in each binding pocket. The molecular docking calculations were carried out for Trp-134- and Trp-212-containing binding sites. Table 1, shows the fitness scores for the ten best docking poses in both Trp-134- and Trp-212-containing binding sites (ChemPLP function) performed on CIP, ENR and PEF. The docking score average suggests that all three fluoroquinolones interact satisfactorily with BSA into the Trp-212-containing binding site than in the Trp-134-containing binding site. To find a statistically significant difference from the theoretical results, it was applied Student's t-test: as the p values for the three fluoroquinolones (1.24×10-2, 2.07×10-2, and 1.89×10-2, for CIP, ENR and PEF, respectively) are less than 5.00×10-2 (95.0% confidence interval), can reject the null hypothesis, indicating a statistically significant difference between the two protein binding sites (Trp-134- and Trp-212- containing binding sites) [37]. Usually, the literature reveals that the ligands which interact preferentially in the site I are composed by carboxylic acid groups and/or bulky heterocyclic molecules dominated by a negative charge or containing azo and/or sulfur groups (e.g. phenylbutazone, azapropazone, tolbutamide, bucolome and sulfisoxazole) rich in non-ligand p pair and π electrons [38,39], whose shows structural similarity characteristics to those in the three fluoroquinolones under study. With the intention of offer a molecular description of the binding between BSA and fluoroquinolones inside the Trp-212- containing binding site, as well as suggesting the main amino acid residues and the main chemical binding force directly involved on the interaction, the highest docking score value of each fluoroquinolone was analyzed individually. Figure 3 depicts the best docking pose for the three fluoroquinolones into site I and Table 2 shows the main amino acid residues involved in the interaction of BSA: CIP, BSA: ENR, and BSA: PEF. Molecular docking results suggested hydrogen bonding and van der Waals interactions as the main intermolecular forces responsible for the complex stabilization for all studied fluoroquinolones. In general, van der Waals and hydrogen bonding are the main binding forces which contribute to interactions between proteins and small organic molecules. However, the first one is usually estimated based on idealized models of the molecular geometry, e.g., spheres or spheroids, involving less energy when compared to hydrogen bonding (energies associated with hydrogen bonds are in the range of 6- 30 kJ/mol (≈ 2-12 kBT) [40-43]. Since ENR presented just one interaction via hydrogen bonding (with Arg-194 residue in a distance of 3.10 Å) compared to three for the other fluoro- quinolones (Arg-194, Arg-217, and Ser-343 residues for CIP within a distance of 3.30, 3.30, and 1.70 Å, respectively, and Arg-198, Trp-212, and Ser-343 residues for PEF within a distance of 3.80, 3.20, and 2.80 Å, respectively), there is an indicative that ENR has weaker interaction toward BSA than CIP and PEF [44]. To clarify, the hydrogen from guanidinium group of the Arg- 194 and Arg-217 residues are potential donors to form hydrogen bonding appropriately with the nitrogen atoms from CIP structure, within a distance of 3.30 Å in both cases. The particular interaction of hydrogen from -OH group in the Ser- 343 residue is also a strong potential donor for hydrogen bonding with oxygen from carboxyl group of CIP structure within a distance of 1.70 Å, showing a strong covalent character [43]. The description of the interaction via van der Waals forces was also suggested between CIP and four kinds of amino acid residues: Leu-197, Arg-198, Trp-212, and Lys-294, within a distance of 2.80, 3.50, 2.00, and 2.60 Å, respectively. Overall, all the fluoroquinolones studied in this work showed remarkable theoretical binding capacity mainly related with Trp-212 residue in domain II, however, the slight structural differences presented among the three fluoroquinolones drove influences on the interaction toward BSA, e.g. the carboxyl group of ENR is not fully buried in the protein binding pocket, and the ligands Chaves and Vazquez / European Journal of Chemistry 12 (2) (2021) 192-196 195 2021 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.12.2.192-196.2103 Table 2. Amino acid residues involved in the interaction BSA:CIP, BSA:ENR, and BSA:PEF in the Trp-212-containing binding site (ChemPLP function). Sample Amino acid residue Interaction Distance (Å) BSA:CIP Arg-194 Hydrogen bonding 3.30 Leu-197 Van der Waals 2.80 Arg-198 Van der Waals 3.50 Trp-212 Van der Waals 2.00 Arg-217 Hydrogen bonding 3.30 Lys-294 Van der Waals 2.60 Ser-343 Hydrogen bonding 1.70 BSA:ENR Arg-194 Hydrogen bonding 3.10 Leu-197 Van der Waals 3.40 Trp-212 Van der Waals 2.50 Arg-217 Van der Waals 2.80 Gln-220 Van der Waals 2.60 Lys-294 Van der Waals 3.60 Val-342 Van der Waals 1.90 BSA:PEF Arg-194 Van der Waals 3.40 Leu-197 Van der Waals 2.50 Arg-198 Hydrogen bonding 3.80 Trp-212 Hydrogen bonding 3.20 Arg-217 Van der Waals 2.30 Ala-341 Van der Waals 3.70 Val-342 Van der Waals 1.20 Ser-343 Hydrogen bonding 2.90 Figure 3. Best docking pose for the interaction between BSA and the three fluoroquinolones in the Trp-212-containing binding site. For each case was showed the zoom representation corresponding to the interaction BSA: CIP, BSA: ENR, and BSA: PEF. Domains I, II, and III are represented as cartoon in yellow, beige and orange, respectively, while the selected amino acid residues, CIP, ENR and PEF are represented as sticks in green, brown, magenta and purple, respectively. Hydrogen: white; oxygen: red; fluorine: light blue and nitrogen: dark blue. CIP and PEF presented qualitatively interaction similarity higher than 70%. Additionally, since bovine serum albumin (BSA) and human serum albumin (HSA) share 76% identity and 88% similarity [35,45,46], the results obtained for BSA might be correlated with HSA binding capacity. 4. Conclusions The molecular docking scores suggested the Trp-212- containing binding site (site I - domain II) as the main binding pocket for the three commercial fluoroquinolones (CIP, ENR, and PEF). Student's t-test indicated a statistically significant difference between the two main protein binding sites (Trp- 134- and Trp-212-containing binding sites). The hydrogen bonding in a minor way and van der Waals forces in a major way are the main chemical interactions involved between BSA and fluoroquinolones. Overall, all fluoroquinolones presented in this study had a significant theoretical binding capacity in the Trp-212-containing binding site, attributed mainly by the slight structural differences among the three ligands. There were 196 Chaves and Vazquez / European Journal of Chemistry 12 (2) (2021) 192-196 2021 – European Journal of Chemistry – CC BY NC – DOI: 10.5155/eurjchem.12.2.192-196.2103 some particular features on the interaction toward BSA, e.g. the carboxyl group of ENR is not entirely buried in the protein binding pocket, as well as this ligand showed lower binding capacity compared to CIP and PEF, suggesting the behaviour of higher partition of ENR to the animal bloodstream compared to other fluoroquinolones. Acknowledgements The authors gratefully acknowledge Professor Carlos Mauricio Rabello de Sant’Anna (Institute of Chemistry at Universidade Federal Rural do Rio de Janeiro) for the molecular docking facilities and the Brazilian agency Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support. Otávio Augusto Chaves also thanks Dr. Thiago Moreno L. Souza from Oswaldo Cruz Foundation (Fiocruz, Rio de Janeiro, Brazil) and Fundação para o Desenvolvimento Científico e Tecnológico em Saúde (FIOTEC, Rio de Janeiro, Brazil) for the grant 117235 in the project VPGDI-032-ARC-20. Disclosure statement Conflict of interests: The authors declare that they have no conflict of interest. Author contributions: Otávio Augusto Chaves conducted the molecular docking calculations. Otávio Augusto Chaves and Leonardo Vazquez wrote the manuscript. Ethical approval: All ethical guidelines have been adhered. Funding Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil). ORCID Otávio Augusto Chaves https://orcid.org/0000-0001-6211-7659 Leonardo Vazquez https://orcid.org/0000-0002-1306-2644 References [1]. Drlica, K. Curr. Opin. Microbiol. 1999, 2, 504–508. [2]. Brown, S. A. J. Vet. Pharmacol. Ther. 1996, 19, 1–14. [3]. Gootz, T. D.; Brighty, K. E. Med. Res. Rev. 1996, 16, 433–486. [4]. Singh, S.; Shukla, S.; Tandia, N.; Kumar, N.; Paliwal, R. Pharm. Sci. Monitor 2014, 5, 184-197. http://www.pharmasm.com/pdf_files/ 20140729051511_20_swatantra.pdf (accessed April 6, 2021). [5]. Kumar, B. S.; Ashok, V.; Kalyani, P.; Nair, G. R. Vet. World 2016, 9, 410– 416. [6]. Committee for veterinary medicinal products. The European Agency for the Evaluation of Medicinal Products – Veterinary Medicines Evaluation Unit, https://www.ema.europa.eu/en/committees/ committee-medicinal-products-veterinary-use-cvmp (accessed April 6, 2021). [7]. Anand, U.; Kurup, L.; Mukherjee, S. Phys. Chem. Chem. Phys. 2012, 14, 4250–4258. [8]. Lizondo, M.; Pons, M.; Gallardo, M.; Estelrich, J. J. Pharm. Biomed. Anal. 1997, 15, 1845–1849. [9]. Bryskier, A. Antibiotiques, agents antibactériens et antifongiques; 1st ed.; Ellipses Éditions Marketing, 1999. [10]. Sárközy, G. Vet. Med. (Praha) 2001, 46, 257–274. [11]. Lekeux, P.; Art, T. Vet. Rec. 1988, 123, 205–207. [12]. Entriken, T. L. Veterinary Pharmaceuticals and Biologicals; 12th ed.; Veterinary Medicine Pub Co, 2001. [13]. Qin, J.; Sun, Y. Mod. Appl. Sci. 2009, 3, 112–114. [14]. Bressolle, F.; Gonçalves, F.; Gouby, A.; Galtier, M. Clin. Pharmacokinet. 1994, 27, 418–446. [15]. Kronfeld, D. S.; Donoghue, S.; Copp, R. L.; Stearns, F. M.; Engle, R. H. J. Dairy Sci. 1982, 65, 1925–1933. [16]. Sułkowska, A.; Maciążek-Jurczyk, M.; Bojko, B.; Równicka, J.; Zubik- Skupień, I.; Temba, E.; Pentak, D.; Sułkowski, W. W. J. Mol. Struct. 2008, 881, 97–106. [17]. He, X. M.; Carter, D. C. Nature 1992, 358, 209–215. [18]. Nerli, B.; Romanini, D.; Picó, G. Chem. Biol. Interact. 1997, 104, 179– 202. [19]. Chaves, O. A.; Schaeffer, E.; Sant’Anna, C. M. R.; Netto-Ferreira, J. C.; Cesarin-Sobrinho, D.; Ferreira, A. B. B. Mediterr. J. Chem. 2016, 5, 331– 339. [20]. Chaves, O. A.; Amorim, A. P. de O.; Castro, L. H. E.; Sant’Anna, C. M. R.; de Oliveira, M. C. C.; Cesarin-Sobrinho, D.; Netto-Ferreira, J. C.; Ferreira, A. B. B. Molecules 2015, 20, 19526–19539. [21]. Chaves, O. A.; da Silva, V. A.; Sant’Anna, C. M. R.; Ferreira, A. B. B.; Ribeiro, T. A. N.; de Carvalho, M. G.; Cesarin-Sobrinho, D.; Netto- Ferreira, J. C. J. Mol. Struct. 2017, 1128, 606–611. [22]. Shim, J. H.; Shen, J. Y.; Kim, M. R.; Lee, C. J.; Kim, I. S. J. Agric. Food Chem. 2003, 51, 7528–7532. [23]. Seedher, N.; Agarwal, P. J. Lumin. 2010, 130, 1841–1848. [24]. Yu, X.; Liu, R.; Ji, D.; Yang, F.; Li, X.; Xie, J.; Zhou, J.; Yi, P. J. Solution Chem. 2011, 40, 521–531. [25]. Ni, Y.; Su, S.; Kokot, S. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2010, 75, 547–552. [26]. Liu, S.; Zhang, L.-W.; Zhang, X.-X. Anal. Sci. 2006, 22, 1515–1518. [27]. Hernández, M.; Aguilar, C.; Borrull, F.; Calull, M. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 2002, 772, 163–172. [28]. Yan, C.; Tong, J.; Xiong, D.; Liu, Y.; Pan, Z. Fenxi Huaxue 2006, 34, 796– 800. [29]. Maya, M. T.; Gonçalves, N. J.; Silva, N. B.; Morais, J. A. J. Chromatogr. 2001, 755, 305–309. [30]. Dowling, P. M.; Wilson, R. C.; Tyler, J. W.; Duran, S. H. J. Vet. Pharmacol. Ther. 1995, 18, 7–12. [31]. Papich, M. G. Am. J. Vet. Res. 2012, 73, 1085–1091. [32]. Bujacz, A. Acta Crystallogr. D Biol. Crystallogr. 2012, 68, 1278–1289. [33]. Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor, R. J. Mol. Biol. 1997, 267, 727–748. [34]. Bujacz, A.; Zielinski, K.; Sekula, B. Proteins 2014, 82, 2199–2208. [35]. Chaves, O. A.; Jesus, C. S. H.; Cruz, P. F.; Sant’Anna, C. M. R.; Brito, R. M. M.; Serpa, C. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2016, 169, 175–181. [36]. DeLano, W. L. PyMOL. https://pymol.org/2/ (accessed April 6, 2021). [37]. Chaves, O.; Teixeira, F.; Guimarães, H.; Braz-Filho, R.; Vieira, I. J.; Sant’Anna, C. M.; Netto-Ferreira, J. C.; Cesarin-Sobrinho, D.; Ferreira, A. J. Braz. Chem. Soc. 2016, 28, 1229–1236. [38]. Yamasaki, K.; Chuang, V. T. G.; Maruyama, T.; Otagiri, M. Biochim. Biophys. Acta 2013, 1830, 5435–5443. [39]. Chaves, O. A.; Soares, B. A.; Maciel, M. A. M.; Sant’Anna, C. M. R.; Netto- Ferreira, J. C.; Cesarin-Sobrinho, D.; Ferreira, A. B. B. J. Braz. Chem. Soc. 2016, 27, 1858–1865. [40]. van der Spoel, D.; van Maaren, P. J.; Larsson, P.; Tîmneanu, N. J. Phys. Chem. B 2006, 110, 4393–4398. [41]. Roth, C. M.; Neal, B. L.; Lenhoff, A. M. Biophys. J. 1996, 70, 977–987. [42]. Silverstein, K. A. T.; Haymet, A. D. J.; Dill, K. A. J. Am. Chem. Soc. 2000, 122, 8037–8041. [43]. Dereka, B.; Yu, Q.; Lewis, N. H. C.; Carpenter, W. B.; Bowman, J. M.; Tokmakoff, A. Science 2021, 371, 160–164. [44]. Naveenraj, S.; Anandan, S. J. Photochem. Photobiol. C: Photochem. Rev. 2013, 14, 53–71. [45]. Paul, B. K.; Samanta, A.; Guchhait, N. J. Phys. Chem. B 2010, 114, 6183– 6196. [46]. Chaves, O. A.; Jesus, C. S. H.; Henriques, E. S.; Brito, R. M. M.; Serpa, C. Photochem. Photobiol. Sci. 2016, 15, 1524–1535. Copyright © 2021 by Authors. This work is published and licensed by Atlanta Publishing House LLC, Atlanta, GA, USA. The full terms of this license are available at http://www.eurjchem.com/index.php/eurjchem/pages/view/terms and incorporate the Creative Commons Attribution-Non Commercial (CC BY NC) (International, v4.0) License (http://creativecommons.org/licenses/by-nc/4.0). By accessing the work, you hereby accept the Terms. This is an open access article distributed under the terms and conditions of the CC BY NC License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited without any further permission from Atlanta Publishing House LLC (European Journal of Chemistry). No use, distribution or reproduction is permitted which does not comply with these terms. Permissions for commercial use of this work beyond the scope of the License (http://www.eurjchem.com/index.php/eurjchem/pages/view/terms) are administered by Atlanta Publishing House LLC (European Journal of Chemistry). https://orcid.org/0000-0001-6211-7659 https://orcid.org/0000-0002-1306-2644 http://www.pharmasm.com/pdf_files/%2020140729051511_20_swatantra.pdf http://www.pharmasm.com/pdf_files/%2020140729051511_20_swatantra.pdf https://www.ema.europa.eu/en/committees/%20committee-medicinal-products-veterinary-use-cvmp https://www.ema.europa.eu/en/committees/%20committee-medicinal-products-veterinary-use-cvmp https://pymol.org/2/ http://www.eurjchem.com/index.php/eurjchem/pages/view/terms http://creativecommons.org/licenses/by-nc/4.0 http://www.eurjchem.com/index.php/eurjchem/pages/view/terms 1. Introduction 2. Experimental 2.1. Molecular descriptor calculation 3. Results and discussion 4. Conclusions Acknowledgements Disclosure statement Funding ORCID References PrintField10: PrintField11: PrintField12: PrintField13: PrintField14: PrintField20: PrintField21: PrintField22: PrintField23: PrintField24: