







































 
 
 

 

47 
 

Agriculture and Food Sciences Research 
Vol. 5, No. 1, 47-51, 2018 

ISSN(E) 2411-6653 / ISSN(P) 2518-0193 
DOI: 10.20448/journal.512.2018.51.47.51 

 

 
 
Evaluation of Some Plant Extracts and Powders in Control of Bean Damping-Off By 
Sclerotinia Sclerotiorum 

 
Zahra Ibrahim El-Gali    

 
 
  

Dept. of Plant Protection, Faculty of Agriculture, Omer AlMuhktar University. El-Beida, Libya 

 

 
Abstract 

The antifungal effect of three botanical powdered plants and their aqueous extracts against 

damping-off disease incidence of bean were evaluated under laboratory and field conditions. Also 

This study investigated the phytochemical profile of these plants. Powder of Peganum harmala, 

Urtica dioica and Helichrysum stoechas  leaves were used in the present work. The botanical plant 

extracts were applied as seed dressing, while the powders were applied as seed coating in vitro or 

were added to the cultivation soil in vivo before or after inoculation with Sclerotinia sclerotiorum 

then sowing. All applied treatments reduced dead seedlings incidence comparing with untreated 

control. Higher significant reduction in disease incidence was observed for H. stoechas treatment 

than that of the others plants. It is interesting to note that botanical plants extract gave a similar 

effect to the powder in reducing disease incidence either at pre- or post-emergence stages of bean 

growth. The content of the active biological compounds different between all plants. 
 

Keywords: Plant extract, Powder, Phytochemical, Damping-off, Sclerotinia sclerotiorum. 

 
Citation | Zahra Ibrahim El-Gali (2018). Evaluation of Some Plant 
Extracts and Powders in Control of Bean Damping-Off By 
Sclerotinia Sclerotiorum. Agriculture and Food Sciences Research, 
5(1): 47-51. 
History:  
Received: 13 March 2018 
Revised: 7 April 2018 
Accepted: 9 April 2018 
Published: 12 April 2018 
Licensed: This work is licensed under a Creative Commons 

Attribution 3.0 License  
Publisher: Asian Online Journal Publishing Group 
 

Funding: This study received no specific financial support. 
Competing Interests: The author declares that there are no conflicts of 
interests regarding the publication of this paper. 
Transparency: The author confirms that the manuscript is an honest, 
accurate, and transparent account of the study was reported; that no vital 
features of the study have been omitted; and that any discrepancies from the 
study as planned have been explained. 
Ethical: This study follows all ethical practices during writing.   

 

 
Contents 
1. Introduction ...................................................................................................................................................................................... 48 
2. Materials and Methods ................................................................................................................................................................... 48 
3. Results ................................................................................................................................................................................................ 49 
4. Discussion .......................................................................................................................................................................................... 50 
5. Conclusion ......................................................................................................................................................................................... 50 
References .............................................................................................................................................................................................. 50 
 

 
 

 

 

 

 

 

 

 

http://crossmark.crossref.org/dialog/?doi=10.20448/journal.512.2018.51.47.51&domain=pdf&date_stamp=2017-01-14
http://creativecommons.org/licenses/by/3.0/
http://creativecommons.org/licenses/by/3.0/
https://orcid.org/orcid-search/quick-search?searchQuery=Zahra%20Ibrahim%20El-Gali


Agriculture and Food Sciences Research, 2018, 5(1): 47-51 

48 
 

 

1. Introduction 
Dry white bean (Phaseolus vulgares L.) is one of the major protein yielding plant found not only in Libya but 

throughout the world due to the presence of high calorie protein. Sclerotinia sclerotiorum is an important fungal 
pathogen with cosmopolitan distribution that has a wide host range [1-3]. Damping-off and root rot disease 
caused by S. sclerotiorum is a serious and persistent diseases problem of bean plants during growing season. Control 
of such diseases mainly depend on fungicidal treatments [4]. However, fungicidal applications cause hazards to 
human health and increase environmental pollution. Therefore, alternative treatments for control of plant diseases 
are needed [5]. Botanical plants made into powder were widely used by ancient civilizations to improve the 
palatability of foods and beverages as well as for their preserving characteristics. Various plant products like gum, 
oil, resins etc. are used as fungicidal agents [6-8]. The biological control of plant diseases may have minimum 
adverse effect on physiological processes of plant and less environmental hazards [9]. The objective of the research 
work performed was to study the antifungal activity of some botanical plant extracts and powders against 
damping-off disease incidence of bean in vivo and in vitro conditions. 
 

2. Materials and Methods 
2.1. Source of Pathogen 

S. sclerotiorum was isolated from dry bean seeds and identified in laboratory of phytopathology, Faculty of 
Agriculture, Omer AlMukhtar University, Libya. 
 

2.2. Plant Materials 
2.2.1. Preparation of Powders 

Three different plant species, Peganum harmala, Urtica dioica and Helichrysum stoechas known for their medicinal 
value in traditional medicine and generally available in wild in Al-Jabal Al-Akhdaer region were selected for the 
study (Fig. 1). The apparently healthy leaves of these plants were collected in flowering time, then washed 
thoroughly with running tap water to remove the dust and dried. The dried  leaves, were crushed into powder with 
the help of grinder. The powders were passed through sieve to get fine powder. The powders of different plant 
were stored in polythene bags for the study.  
 

2.2.2. Preparation of Aqueous Extracts 
Fifty grams of each of above mentioned botanical plant materials in powder form was homogenized by 

laboratory blender in 50 ml distilled water for 10 min, then left in dark place for 24 h for tissue maceration. The 
extracts were filtered through thin cheesecloth sheets. The final extracts/supernatant were filtered through 

Whatman No. 1 filter paper and sterilized by Zeits filter (0.24 μl), then collected separately in sterile dark glass 
tight bottles. The obtained extracts served as the crude extract (100 % concentration) and kept in a refrigerator at 
4°±1 until use. 
 

 
Fig-1. Types of used plants  

                    (Source: The photograph was took by Author's camera) 

 
2.3. Application of Plant Materials for Damping-Off Control 
2.3.1. Laboratory Experiment 

The plant materials were evaluated for bean damping-off control by using different methods of application. The 
wet method depends on soaking the bean seeds in the plant extract for 12, 24 and 36h., then left for 1h to dry, and 
in pure water for check treatment. The dry method depends on mixing the seed with the formula, Carboxy Methyl 
Cellulose (0.1g CMC in 10ml water) as adhesive material. and were rolled on plant powder to help it for adhesion. 
For studying the disease in lab., Petri plates with Potato Sucrose Agar medium were inoculated with S. sclerotiorum 
and incubated at 23±2°C. when the entire plate was covered with the white mycelium, the mycelial mat was 
covered with sterilized soil, 1.0g thick. Soaked and coated seeds were germinated in plates and  incubated at room 
temperature, four replicates were used for each treatment. In control plates, the seeds without treatment were 
planted in plates medium.  
 

2.3.2. Field Experiment 
Under field conditions, plastic pots (15 cm diam.) were used. Pots were sterilized by immersing in 5% formalin 

solution for 15 min., and left several days before being used, then filled with sterilized sand and clay soil (1:1 v/v). 
The soil had infestation of 5 fungus sclerotia and irrigated for one week before sowing. The seeds soaked were 
sown at rate of  5 seeds/ pot. The botanical plant powder tested was applied by two methods: a) Soil mixed with 
powder at rate of  3g powder/ 300g  and left two days before infestation with sclerotia and irrigated for one week.  
b) Soil infested with sclerotia and irrigated for one week before powder added. Surface sterilized seeds were  
planted at the rate of 5 seeds per pot in two applications.   

 
 



Agriculture and Food Sciences Research, 2018, 5(1): 47-51 

49 
 

 

2.4. Disease Assessments 
Disease effects due to S. sclerotiorum in the different treatments were assessed at 10 days after planting as 

decayed seeds, death of seedlings (pre and post emergence) and seedling survival after 30 days. These parameters 
were calculated and expressed as percentages.  
 

2.5. Data Analysis  
All experiments were conducted on the basis of completely randomized designs (CRD). Each treatment was 

replicated at least five times. For statistical analysis, data were subjected to the analysis of variance (ANOVA) 
using Co Stat Program. Angular transformed values were used for data analysis. Statistical comparisons among 
means were performed using Duncan’s multiple range test (DMRT).   
 

 
Fig-2. Effect of plant extracts and powders on seed decay. 

                                                                             (Source: The photograph was took by Author's camera) 

 
2.6. Phytochemical Analysis 

Phytochemical analysis of the extracts was done by following the methods described previously [10-14]. 
 

3. Results  
From observations in the test, after 10 days, all the seeds had not grown in the plate treated with P. harmala 

and in the control plates, and  it appeared completely decay. The dressing with H. stoechas was protected the seed 
against fungus invasion. In the treatment plates, U. dioica  powder was effect in reduce seed decay than plant 
extract, while extract and powder of H. stoechas was the best in control seed decay disease (Fig. 2).    

The decrease in seeds rot was observed in seeds that were treated with extract or coated with powder of H. 
stoechas,  at  ratio of 20% and 6.7% compared with 100% in control treatment (Table 1). H. stoechas was more 
effective than others plants against seeds decay. 
 

Table-1. Effect of seed treatment with plant preparation on the percentage of bean seed decay In Vitro. 

Treatments 

Extract 

Powder Time (h) 

12 24 36 

P. harmala.  100 (100.0) a 100 (100.0) a 100 (100.0) a 93.3 (75.00) a 

U. dioica  86.7 (68.53) a 93.3 (75.00) a 100 (100.0) a 33.3 (35.24). b 

H. stoechas 20.0 (26.56) b 20.0 (26.56) b 20.0 (26.56) b 06.7 (15.00) b 

Con.  93.3 (75.00) a 93.3 (75.00) a 100 (100.0) a 100 (100.0) a 
 
LSD at 5% 

Ex.:       15.77 
T:            NS 
Ex × T:   NS 

 
28.95 

Note: Each value is mean of four replicates 
Percentage of infection transformed data by the arcsine square before analysis. 
NS: Non-significant 

 
Results in Table (2) indicate that the treatment with H. stoechas was significantly reduced the seed decay 

disease of bean plants comparing with treatments with P. harmala and U. dioica and untreated check control 
treatment. It recorded disease incidence (33.3, 28 and 4%)  and seedling healthy (66.7, 72. 60%) in both extract and 
powder compared with 86.7% dead Seedlings  and 13.3% seedlings healthy in control treatment. In terms of effect 
of extracts and powders on disease in field the study  recorded  occurrence  the reduction in seedlings death and 
increased seedlings survival after seeds  treatment with extract or soil amended with powder before or after  
inoculation with fungal sclerotial. The H. stoechas weed was more effective followed by U. dioica. 
 
 



Agriculture and Food Sciences Research, 2018, 5(1): 47-51 

50 
 

 

Table-2. Effect of dressing bean seeds with plant preparation on percentage of bean damping-off disease 

Treatment 

Formula tested 

Suspension 
Powder 

Before inoculation After inoculation 

Dead 
Seedlings 

Seedlings 
healthy 

Dead 
Seedlings 

Seedlings 
healthy 

Dead 
Seedlings 

Seedlings 
healthy 

P. harmala.  60.0 (50.77) ab 40.0 (39.23) ab 48.0 (43.85)  52.0 (46.15)  88.0 (69.73)  
12.0 
(20.27)  

U. dioica  73.3 (58.89) ab 26.7 (31.11) bc 40.0 (39.23)  60.0 (50.77)  36.0 (36.87) 
64.0 
(53.13) 

H. stoechas 33.3 (35.21) b 66.7 (54.76) a 28.0 (31.95) 72.0 (58.05) 40.0 (39.23)  
60.0 
(50.77)  

Con.  86.7 (68.70) a 13.3 (31.39) c 86.7 (68.70) 13.3 (31.39) 86.7 (68.70) 
13.3 
(31.39) 

LSD 5% 24.9 17.4 
Method:           NS 
Treatment:      16.79 
M  ×  T:           NS 

Method:           NS 
Treatment:      11.88 
M  ×  T:           NS 

Note: Each value is mean of three replicates. 
Percentage of infection transformed data by the arcsine square before analysis 
Values followed by the same letter(s) are not significantly different at P= 0.05. 
NS: Non-significant. 

 
Phytochemical properties of extracts of P. harmala, U. dioica and H. stoechas are represented in Table (3). 

Flavonoids were not found in P. harmala and U. dioica but were found to be the major phytoconstituent along with 
glycosides, phenols, tannins, resins and terpenoids  in H. stoechas.  Saponins were present as the major 
phytoconstituents irrespective of P. harmala and U. dioica . P. harmala  extract was poorer in antifungal compounds.  
 

Table-3. Phytochemical constituents of aqueous extracts of different plants 

                Plants 
Compound     

P. harmala. U. dioica H. stoechas 

Alkaloids + - - 
Anthraquinones - - - 
Flavonoids - - + 
Glycosides - + + 
Phenols - + + 
Saponins + + - 
Tannins - + + 
Terpenoids - + + 
Phlobatanins - - - 
Resins  - + + 
Note: +: Found, -: Not found 

 

4. Discussion 
Naturally occurring products from plants have played an important role in the discovery of new therapeutic 

agents since ancient times. The use of plant extracts and phytochemicals, with known antimicrobial properties, 
may be of immense importance in therapeutic treatments. Synthetic fungicides are currently used as the primary 
means for the control of plant diseases. However, the alternative control methods are needed because of the 
negative public perceptions about the use of synthetic chemicals, resistance to fungicides among fungal pathogens, 
and high development cost of new chemicals. The uses of plant derived products as diseases control agents have 
been studied, since they tend to have low mammalian toxicity, less environmental effects and wide public 
acceptance [5]. To develop environment-friendly alternatives to synthetic fungicides for the control of fungal plant 
diseases, the interest on essential oils and plant extracts has been increased [9]. The results obtained in the present 
work indicate that the powders were more effective than extracts. This results agreement with that obtained by El-
Mougy and Abdel-Kader [15] and Mokhtar, et al. [16]. H. stoechas extract or powder had antifungal activity 
against plant pathogenic fungus tested in the present study. Numerous studies have been conducted in the past few 
years to prove such efficiency [17-20]. Plant of the genes Helichrysum are prolific producer secondery metabolites 
as antiviral, antifungal, antimicrobial and anti-inflammatory [20-23]. The efficiency of H. stoechas  may be due to 
the high content of phenols, flavonoids, glycosides, tannins, terpenids and resins in leaves more than the others 
plants. So, it is interested to state that we can used H. stoechas extracts and/or powders less expensive for 
controlling plant diseases under field.  

 
5. Conclusion 

Promising applicable technique could be suggested in the light of the results obtained. The use of soil drench 
treatment with botanical plants powder might be considered as safe, cheap and easily applied method for 
controlling such soil-borne plant pathogens as eco-friendly means, and considering the avoidance of environmental 
pollution and the side effect of pesticide  

 
References  
[1] M. Malvárez, I. Carbone, N. J. Grünwald, K. V. Subbarao, M. Schafer, and L. M. Kohn, "New populations of Sclerotinia 

sclerotiorum from lettuce in California and peas and lentils in Washington," Phytopathology, vol. 97, pp. 470-483, 2007. View at Google 

Scholar | View at Publisher 
[2] Z. I. El-Gali, "Cultural, morphological and Physiological studies on some isolates of sclerotinia sclerotiorum Libyan," Journal of 

Plant Protection Research, vol. 1, pp. 11-16, 2010.  

https://scholar.google.com/scholar?hl=en&q=New%20populations%20of%20Sclerotinia%20sclerotiorum%20from%20lettuce%20in%20California%20and%20peas%20and%20lentils%20in%20Washington
https://scholar.google.com/scholar?hl=en&q=New%20populations%20of%20Sclerotinia%20sclerotiorum%20from%20lettuce%20in%20California%20and%20peas%20and%20lentils%20in%20Washington
http://dx.doi.org/10.1094/phyto-97-4-0470


Agriculture and Food Sciences Research, 2018, 5(1): 47-51 

51 
 

 

[3] M. M. Abdel-Kader, N. S. El-Mougy, and S. M. Lashin, "Chemical and biological measures against sclerotinia spp. The causal of 
foliage blight disease of cucumber and pepper plants in Egypt- A review," International Journal of Engineering & Technology, vol. 3, 
pp. 302- 311, 2014.  

[4] B. A. Rauf, "Seed-borne disease problems of legume crops in Pakistan," Pakistan Journal of Scientific and Industrial Research, vol. 43, 
pp. 249-254, 2000. View at Google Scholar  

[5] N. S. El-Mougy, F. Abd-El-Karem, G. E. Nadia, and Y. O. Fotouh, "Application of fungicides alternatives for controlling cowpea 
root rot diseases under greenhouse and field conditions," Egyptian Journal of Phytopathology, vol. 32, pp. 23-35, 2004. View at Google 

Scholar   
[6] D. Yazdani, Y. H. Tan, M. A. Zainal Abidin, and I. B. Jaganath, "A review on bioactive compounds isolated from plants against 

plant pathogenic fungi," Journal of Medicinal Plants Research, vol. 5, pp. 6584 -6589, 2011. View at Google Scholar   
[7] D. Hada and K. Sharma, "A review: Plant extracts a new source of antimicrobial potential," Research Journal of Pharmaceutical, 

Biological and Chemical Sciences (RJPBCS), vol. 5, pp. 597- 628, 2014. View at Google Scholar   
[8] D. Hassan, M. N. Galti, and B. Ali, "Use of Neem (Azadirachta Indica) seed powder to treat groundnut seed-borne pathogenic 

fungi," European Journal of Experimental Biology, vol. 5, pp. 69-73, 2015. View at Google Scholar   
[9] S. K. Okwute, Plants as potential sources of pesticidal agents: A Review. Chapter 9, In Pesticide – Advances in Chemical and Botanical 

Pesticides. Idu, Abuja, Nigeria: National Institute for Pharmaceutical Research and Development, 2012. 
[10] I. M. Shihata, "A pharmacolog-ical study of anagallis arvensis," MS.c. Thesis, Faculty of Vet. Med, Cairo University, Egypt, 1951. 
[11] G. E. Trease and W. C. Evans, Pharmacognosy. Pytochemistry: Introduction in general methods, 11th ed. London: Bailliere Tindll. pp: 

227-247, 2002. 
[12] J. B. Harbone, Phytochemical methods. London: Chapman and Hall. pp: 183 – 195, 1973. 
[13] H. O. Edeoga, D. E. Okwu, and B. O. Mbaebie, Phytochemical constituents of some Nigerian medicinal plants. African Journal of 

Biotechnology, vol. 4, pp. 685-688, 2005. 
[14] J. U. Ewansiha, S. A. Garba, M. Galadima, S. Y. Daniyan, and M. B. Busari, "Therapeutic potency of citrus Limon (L) Burm. F. 

(Lemon) peel extract against some disease causing microorganisms," International Journal of Research Studies in Biosciences, vol. 4, pp. 
30-39, 2016.  

[15] N. S. El-Mougy and M. M. Abdel-Kader, "Antifungal effect of powdered spices and their extracts on growth and activity of some 
fungi in relation to damping-off disease control," Journal of Plant Protection Research, vol. 47, pp. 267-278, 2007. View at Google Scholar  

[16] M. M. Mokhtar, N. S. El-Mougy, F. Abdel-Kareem, N. G. El-Gamaal, and Y. O. Fatouh, "Effect of some botanical powdered plants 
against root rot disease incidence of bean under field conditions," International Journal of Engineering & Technology, vol. 4, pp. 162-
167, 2014. View at Google Scholar   

[17] A. Bogdadi, L. Kokoska, J. Havlik, P. Kloucek, V. Rada, and K. Vorisek, "In Vitro antimicrobial activity of some Libyan medicinal 
plant extracts," Pharmaceutical Biology, vol. 45, pp. 386–391, 2007. View at Google Scholar | View at Publisher 

[18] S. AlBayrak, A. Aksoy, O. Sağdic, and U. Budak, "Phenolic compounds and antioxidant and antimicrobial properties of 
Helichrysum species collected from eastern anatolia, Turkey," Turkish Journal of Biology, vol. 34, pp. 463-473, 2010. View at Google 

Scholar   
[19] M. Buzayan and F. El-Garbulli, "Antibacterial activity of medicinal aqueous plant extracts against Mycobacterium tuberculosis," 

Malaysian Journal of Microbiology, vol. 8, pp. 203-206, 2012. View at Google Scholar   

[20] D. J. Bigović, T. R. Stević, T. R. Janković, N. B. Noveski, D. S. Radanović, D. S. Pljevljakušić, and Z. R. Djurić, "Antimicrobial 
activity of Helichrysum plicatum DC," Hemijska industrija, vol. 71, pp. 337–342, 2017. View at Google Scholar | View at Publisher 

[21] A. Sala, M. C. Recio, G. R. Schinella, S. Manez, and G. R.M., "Assessment of the antiflammatory activity and free radical scavenger 
activity of tiliroside," European Journal of Pharmacology, vol. 641, pp. 53- 61, 2003. View at Google Scholar | View at Publisher 

[22] S. F. Van Vurren, A. M. Viligoen, F. R. Van Zyl, K. Van Heerden, K. Husnu, and C. Baser, "The antimicrobial, antimalarial and 
toxicity profiles of helihumulone, leaf essential oil and extracts of Helichrysum oymosum (L.) D. Don subsp. oymosum," South 
African Journal of Botany, vol. 72, pp. 287- 290, 2006. View at Google Scholar | View at Publisher 

[23] E. A. Sobhy and S. S. El-Feky, "Chemical constituents and antimicrobial activity of helichrysum stoechas," Asian Journal of Plant 
Sciences, vol. 6, pp. 692-695, 2007. View at Google Scholar | View at Publisher 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

Asian Online Journal Publishing Group is not responsible or answerable for any loss, damage or liability, etc. caused in relation to/arising out of the use of the content. 
Any queries should be directed to the corresponding author of the article. 
 

https://scholar.google.com/scholar?hl=en&q=Seed-borne%20disease%20problems%20of%20legume%20crops%20in%20Pakistan
https://scholar.google.com/scholar?hl=en&q=Application%20of%20fungicides%20alternatives%20for%20controlling%20cowpea%20root%20rot%20diseases%20under%20greenhouse%20and%20field%20conditions
https://scholar.google.com/scholar?hl=en&q=Application%20of%20fungicides%20alternatives%20for%20controlling%20cowpea%20root%20rot%20diseases%20under%20greenhouse%20and%20field%20conditions
https://scholar.google.com/scholar?hl=en&q=A%20review%20on%20bioactive%20compounds%20isolated%20from%20plants%20against%20plant%20pathogenic%20fungi
https://scholar.google.com/scholar?hl=en&q=A%20review:%20Plant%20extracts%20a%20new%20source%20of%20antimicrobial%20potential
https://scholar.google.com/scholar?hl=en&q=Use%20of%20Neem%20(Azadirachta%20Indica)%20seed%20powder%20to%20treat%20groundnut%20seed-borne%20pathogenic%20fungi
https://scholar.google.com/scholar?hl=en&q=Antifungal%20effect%20of%20powdered%20spices%20and%20their%20extracts%20on%20growth%20and%20activity%20of%20some%20fungi%20in%20relation%20to%20damping-off%20disease%20control
https://scholar.google.com/scholar?hl=en&q=Effect%20of%20some%20botanical%20powdered%20plants%20against%20root%20rot%20disease%20incidence%20of%20bean%20under%20field%20conditions
https://scholar.google.com/scholar?hl=en&q=In%20Vitro%20antimicrobial%20activity%20of%20some%20Libyan%20medicinal%20plant%20extracts
http://dx.doi.org/10.1080/13880200701215026
https://scholar.google.com/scholar?hl=en&q=Phenolic%20compounds%20and%20antioxidant%20and%20antimicrobial%20properties%20of%20Helichrysum%20species%20collected%20from%20eastern%20anatolia,%20Turkey
https://scholar.google.com/scholar?hl=en&q=Phenolic%20compounds%20and%20antioxidant%20and%20antimicrobial%20properties%20of%20Helichrysum%20species%20collected%20from%20eastern%20anatolia,%20Turkey
https://scholar.google.com/scholar?hl=en&q=Antibacterial%20activity%20of%20medicinal%20aqueous%20plant%20extracts%20against%20Mycobacterium%20tuberculosis
https://scholar.google.com/scholar?hl=en&q=Antimicrobial%20activity%20of%20Helichrysum%20plicatum%20DC
http://dx.doi.org/10.2298/hemind160118044b
https://scholar.google.com/scholar?hl=en&q=Assessment%20of%20the%20antiflammatory%20activity%20and%20free%20radical%20scavenger%20activity%20of%20tiliroside
http://dx.doi.org/10.1016/s0014-2999(02)02953-9
https://scholar.google.com/scholar?hl=en&q=The%20antimicrobial,%20antimalarial%20and%20toxicity%20profiles%20of%20helihumulone,%20leaf%20essential%20oil%20and%20extracts%20of%20Helichrysum%20oymosum%20(L.)%20D.%20Don%20subsp.%20oymosum
http://dx.doi.org/10.1016/j.sajb.2005.07.007
https://scholar.google.com/scholar?hl=en&q=Chemical%20constituents%20and%20antimicrobial%20activity%20of%20helichrysum%20stoechas
http://dx.doi.org/10.3923/ajps.2007.692.695

