Polyphenols, antioxidant activity and mode of action of antimicrobial compounds of Dittrichia viscosa extracts

Abstract

In order to promote the spontaneous plant Dittrichia viscosa known by its use in traditional medicine, the content of phenolic compound in the aqueous and ethanolic extracts was determined according to the colorimetric method based on the Folin-Ciocalteu reagent, and the antioxidant activity which was evaluated by two methods: DPPH and FRAP. For antimicrobial activity, the microtiter microplate method was applied to the yeast Candida albicans and to two bacteria Staphylococcus aureus and Escherichia coli. Regarding the mode of action of the extracts of tested germs, an evaluation of the nucleic acids released during the lysis of the treated cells was carried by the spectrophotometric assay at wave length 260 nm. The results revealed that the extracts have an interesting content of polyphenols, which is higher in the ethanolic extract. Antioxidant and antimicrobial activities are higher for the alcoholic extract than the decoction. The MIC for E. coli is 0.28 ± 0.05 mg / ml, 2.290 ± 0.20 mg / ml for Staphylococcus aureus and 33.33 ± 0.33 mg / ml for C. albicans. The alcoholic extract  and decocted of  D. viscosa act  respectively by damaging the bacterial and yeast wall.