Mol2Net-04 Antiviral activity of the essential oil of conyza - - PDF document

Mol2Net-04, 2018, BIOCHEMPHYS-01 (pages 1- x, type of paper, doi: xxx-xxxx http://sciforum.net/conference/mol2net-4

Mol2Net-04 Antiviral activity of the essential oil of conyza canadensis

Manel Ben Ali1, 2*, Lobna Daoud1, Adel Hadj Brahim1 , Houda Hmani1, Mouna Jlidi1, Samir Bejar1 and Mamdouh Ben Ali1,2

1Laboratory of Microbial Biotechnology and Engineering Enzymes (LBMIE), Center of Biotechnology

• f Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, PO Box 1177 Sfax 3018, Tunisia

E-Mails: lobna.daoudm@gmail.com (Lobna daoud); adelhadjibrahim@gmail.com (Adel Hadj brahim); houda_enis@yahoo.fr (Houda hmani); jlidimanno@yahoo.fr (Mouna Jlidi) ; samir.bejar@cbs.rnrt.tn (Samir Bejar)

2Astrum Biotech, Business incubator, Center of Biotechnology of Sfax (CBS), University of Sfax,

Road of Sidi Mansour km 6, PO Box 1177 Sfax 3018, Tunisia; E-Mail: mamdouh.benali@cbs.rnrt.tn; * Corresponding author: E-Mail: manel.benali@gmail.com Received: / Accepted: / Published: Abstract: In this study, we were interested in the characterization of Conyza canadensis essential oil composition and evaluation of the antiviral activity from Conyza’s plant extracts. Terpenoids, phenols, sesquiterpenoids and triterpenoids were the major compounds identified from plant essential oil analyzed by gas-chromatography coupled to mass spectrometry. The test of activities of the extracts from different parts (leave, flower and stalk) of Conyza canadensis revealed that this plant has a remarkable antiviral activity. This activity was evaluated for inhibition of Dengue virus (DV), West Nile virus (WNV), Hepatitis C virus (HCV) and Human Immunodeficiency virus (HIV) polymerases. Due to his important antiviral activity, the crude methanolic stalk extract (89% of inhibition) was subjected to silica gel column chromatography to obtain eleven fractions (A-K). None of those fractions, tested at 50 μg/ml, was active against HCV and HIV polymerases but six fractions (B, C, D, E, I and J) were active against DEN and WN polymerases. These results were confirmed at lower concentration (10 μg/ml). Keywords: conyza canadensis; essential oil; antiviral activity

• 1. Introduction

Viral infections are an important health problem all over the world, both in developed and developing countries, due to their morbidity and mortality. The development of a new antiviral drug is a difficult task taking into account the poor selective toxicity and fast selection of resistant viral variants with the existing drugs. Frequencies of viral resistance to antiviral drugs are increasing and the difficulty of virus latency remains unsolved. The screening of plants as a possible source of antivirals has led to the discovery of potent inhibitors of in vitro viral growth[1,2,3,4,5] and the use

• f

the ethnopharmacological approach enhances the probability of identifying new bioactive plant compounds[6,7]

SciForum

Mol2Net, 2018, 1(Section A, B, C, etc.), 1- x, type of paper, doi: xxx-xxxx 2

20 40 60 80 100 inhibition percentage leaves flow ers stalks extracts DENGUE

20 40 60 80 100 inhibition percentage leaves flow ers stalks extracts HCV 20 40 60 80 100 inhibition percentage leaves flow ers stalks extracts HIV 20 40 60 80 100 % of inhibition A B C D E F G H I fractions WN 20 40 60 80 100

% of inhibition

A B C D E F G H I

fractions DENGUE

Due to useful and reputations importance of the plant conyza Canadensis, we are interesting in this paper to the evaluation of the antiviral activities of extracts of different parts this plant against four viruses polymerases belonging to two viruses family: the flaviviridae ( dengue , west nile , HCV) and retrovirtidaea (HIV).

• 2. Results and Discussion

Analysis of the of Conyza essential oil (whole plant) by mass spectrometry coupled with gas chromatography (GC/MS) resulted in the identification of a dozen products of different chemical families (table 2-1): This analysis shows that the essential oil of Erigeron canadensis is quite rich in compounds of which the most abundant are Citronellol (22.03%), beta-maaliène (13.35%), butyl hydroxy toluene (12.12%), 2-cyclopentyl-P-cresol (11.12%) , geraniol (5.9%), Alloaromadendrène (4.64%) and Aromandrène (3.9%). The effect of the methanol extracts, at 50µg/ml, of the different plant parts was tested on DEN, HCV and HIV polymerase. Off all the extracts tested, only the extracts of the leaves and stalks extract exhibited the antiviral activity against Dengue and HCV viruses. The most active extract was the stalks methanolic extract of Conyza Canadensis against Dengue virus with 87% inhibition percentage. No significant antiviral activity was deducted against HIV virus for leaves, flowers and stalks extract (Figure1). Figure 1. Variation of DENGUE virus (DEN), hepatitis C virus (HCV) and Human immunodeficiency virus (HIV) inhibition by methanolic extracts of each plant parts. Results are expressed as percentages of inhibition relative to each part. Due to his important antiviral activity, the crude methanolic stalks extract was subjected to silica gel column chromatography to produce nine fractions (A - I) which were again tested for their anti- polymerase character of DEN, WN, HCV and HIV viruses (figure 2).

Mol2Net-04, 2018, BIOCHEMPHYS-01 (pages 1- x, type of paper, doi: xxx-xxxx http://sciforum.net/conference/mol2net-4

20 40 60 80 100

% of inhibition

A B C D E F G H I

fractions HIV 20 40 60 80 100

% of inhibition

A B C D E F G H I

fractions

HCV

Figure 2: Variation of DENGUE virus (DEN), hepatitis C virus (HCV) and Human immunodeficiency virus (HIV) inhibition by the methanolic stalks extract’s fractions. Results are expressed as percentages of inhibition relative to each fraction. We found that none of the nine fractions was active against HCV and HIV viruses polymerases but the fractions (B, C,D,E) were active against DEN and WN viruses polymerases. All the fractions are tested at 50µg/ ml concentrations. To be sure of the antiviral character of these fractions, each one was tested again tested against the four polymerases studied but with 10µg/ml as concentration. The variation of inhibition shows that fractions C,D and E displayed the best selective antiviral activity against dengue and West Nile.

• 3. Materials and Methods

Plant parts: leaves, flowers or stalks, were dried at room temperature for 2–3 weeks. Dried plant Material was chopped and extracted by maceration with methylene dichloride (CH2Cl2) then methanol (MeOH) for 24h. We are interested in this paper to the methanol

• extracts. After filtration the crude extracts were

evaporated to dryness in a vacuum evaporator under reduced pressure then tested for antiviral activity. Stalks methanol extract (SM) was found to have the most potent antiviral activity. Therefore, a part of this extract (5 g) was further fractionated by column chromatography on silica gel-60 and eluted step-wise with increasing amounts of methanol in Methylene dichloride respectively CH2Cl2/ MeOH to afford fractions (A, B, C, D, E, F, G, H, I) tested for antiviral activity. The antiviral activity is tested according to determined protocols with precise operating conditions to each type of polymerase used. Measurement of the inhibition degree of a studied extract is done by calculating the number

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remaining tritium-labelled phosphates (introduced as nucleotides and intervening during the polymerization reaction) after the reaction in presence of the extract. This number will be compared to which present in the absence of extract after the same reaction, under the same conditions.

• 4. Conclusions

Due to the antiviral test activity, Conyza Canadensis stalks methanolic extract C,D and E fractions deserve a special attention in further studies such characterisation of the active compounds and new antiviral assays. References and Notes 1. Vanden Berghe, D., Vlietinck, A., Van Hoof, L. Plant products as potential antiviral agents. Bulletin de l’Institute Pasteur 1986; 84, 101–147. 2. Tabba, H., Shihman, Chang, R., Smith, K. Isolation,purification and partial characterization of prunellin, an anti-HIV component from aqueous extracts of Prunella vulgaris. Antiviral Research 1986, 11, 263–274. 3. Hudson, J.B. Antiviral Compounds from Plants. CRC Press, Boca Raton, FL.1989

Mol2Net-04, 2018, BIOCHEMPHYS-01 (pages 1- x, type of paper, doi: xxx-xxxx http://sciforum.net/conference/mol2net-4 4 4. Garcı´a, G., Campos, R., de Torres, R., Broussalis, A., Ferraro, G., Martino, V., Coussio, J. Antiherpetic activity of some Argentine medicinal plants. Fitoterapia, 1990, 6, 542–546. 5. Cavallaro, L., Garcı´a, G., Broussalis, A., Martino, V., Ferraro, G., Coussio, J., de Torres, R., Campos, R., 1995. Antiherpetic in vitro activity of Gamochaeta simplicicaulis. Phytotherapy Research, 1995, 9, 176–179. 6. Vlietinck, A., Vanden Berghe, D. Can ethnopharmacology contribute to the development of

• antiviral. Journal of Ethnopharmacology, 1991, 32, 141–153.

7. Baker, J., Borris, R., Carte´, B., Cragg, G., Gupta, M., Iwu, M., Madulid, D., Tyler, V., 1995. Natural product drug discovery and development: New perspectives on international

• collaboration. Journal of Natural Products 58, 1325–1357