Our objective in this work is evaluated the antibacterial, antifungal and antioxidant activity of the phytochymic compounds of the roots and leaves of a species Withania frutescens. In the first part, the phenolic compound is determinate by the Folin-Ciocalteau reaction, the richness of the roots in polyphenols (53.33 ± 1.20 mg EGA/g Extract) is six times higher than that of the leaves. The antioxidant test is evaluated by four methods: DPPH test, reducing power test (FRAP), total antioxidant capacity (CAT) and the ß-carotene discoloration test. The IC-50 values of the DPPH test of the studied parts are of the order of 0.36 µg/ml and 6.63 µg/ml, which showed a lower anti-free radical activity than that of BHT (0.12 µg/ml). The results obtained by the FRAP method revealed a low reducing power of iron for two extracts (EC-50 of 0.45%) compared to Quercetine (EC-50 of 0.03%). The compounds of root and leaf extracts have a significant total antioxidant capacity, respectively 477.65 ± 37.60 and 317.03 ± 46.64 mg EAA/g Extract. In the β-carotene discoloration test, extracts from the aerial and underground parts showed antioxidant activity of 57% followed by (36%), respectively. The evaluation of the antibacterial activity of in vitro extracts against microorganisms is carried out by two methods: disc diffusion and microdilution. The results show that the extracts exert an intermediate inhibitory effect (inhibition diameter between 8 and 15 mm, the smallest MIC obtained is 2.80 mg/ml) on all strains tested. The antifungal activity was estimated by determining the growth inhibition rate of the fungus tested. Indeed, the compounds studied exhibit a good antifungal effect since the minimum inhibitory concentration (MIC) of 4.5 mg/ml for root extract and 9 mg/ml for leaf extract.
Keywords: Antibacterial; Antifungal; Antioxidant; Leaf; Polyphenols; Root.
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