ABSTRACT
In the present investigation, extracts obtained from L. guyonianum Durieu ex Boiss. aerial parts were used to evaluate total phenolic, flavonoid and tannin contents. A study of antioxidant activities of the prepared samples was carried out on the basis of 1,1-Diphenyl-2-picrylhydrazyl [DPPH], 2-2'-azino-bis-[3-ethylbenz-thiazoline-6-sulfonic acid] [ABTS+.] and ferric reducing antioxidant power [FRAP] assays. Moreover, the efficiency of methanolic, chloroformic and petroleum ether extracts and the deriving fractions from the methanolic extract was tested against human bacterial and fungal pathogenic strains using micro dilution method in 96 multiwell microtiter plate. Furthermore, leaves and stems extracts were subjected to RP-HPLC for phenolic compounds identification. Results showed that polyphenolic contents and antioxidant activities varied considerably as function of solvent polarity. Moreover, antiradical capacities against DPPH, ABTS+. and reducing power were maxima in methanol aerial parts extract which showed the highest polyphenol contents [134mg CE/g DW]. The antimicrobial activities showed that methanolic, chloroformic and petroleum ether extracts were found to be most potent against Pseudomonas aeruginosa and Staphylococcus aureus with MIC values of 23 and 46micro g.mL[-1], respectively. The fractions F[13] and F[16] have a great antifungal potential against Candida glabrata, Candida krusei and Candida parapsilesis [MIC=39micro g.mL-1]. The RP-HPLC analysis lead the identification of gallic, procatechuic and trans-cinnamic acids, methyl-4-hydroxybenzoate, n-propyl-3,4,5- trihydroxybenzoate, epicatechin, naringin and myricetin in L. guyonianum Durieu ex Boiss. leaves and stems extracts
ABSTRACT
Vitis vinifera L.is a traditional Asian herb widely used for different health problems. In the present research, the ethanolic and the aqueous extracts of Vitis vinifera L. leaves collected from shrub, grown in Tunisia, were prepared and evaluated for the antileishmanial activity against Leishmani ainfantum promastigotes. The inhibitory concentration 50 [IC[50]] was determined and the results showed that the etahnolic extract is more active than the aqueous one [IC[50]= 0.108 mg/mL]. Microscopic observations showed that the ethanolic extract promoted the destruction of cytoplasmic and nuclear membranes of Leishmani ainfantum promastigotes and altered the overall shape of the cell. In order to explain the difference of antileishmanial activity between ethanolic and aqueous extracts, anthocyanins amount was determined by spectrophotometry. It was found that the ethanolic extract is richer in anthocyanins than the aqueous one which can explain the higher antileishmanial activity of the ethanolic extract