In vitro antioxidant activities of total flavonoids extracts from leaves and stems of Adenia lobata (Jacq.) Engl. (Passifloraceae)

摘要

Oxidant stress is implied in numerous illnesses as a triggering factor or partner to their complications. The present work?aimed?to?determine?the antioxidant activity of total flavonoids extracts from?A. lobata?and to identify the molecules that are supposed to be responsible for this activity. The crude?extracts,?obtained?by maceration in 70% (v/v) aqueous methanol, have been?extracted?successively by hexane, chloroform, ethyl acetate and n-butanol. The crude (S1, S2), ethyl acetate (S1III, S2III) and n-butanol (S1IV, S2IV) extracts underwent a phytochemical screening in order to test the radical scavenging activity against 1, 1’ - diphenyl-2-picrylhydrazyl (DPPH). Qualitative analysis by thin layer chromatography permitted the study to put in evidence the flavonoids content of the different extracts. Contents in phenolic compounds were relatively high in the stems (3604 ± 511, 11 μg GAE/g) in relation to the leaves of?A. lobata?(3240 ± 711, 05 μg GAE/g). EC50?of 6, 422.5, 430 and 357.5 μg/ml were graphically determined for vitamine C, S1III, S2III, S1IV?and S2IVrespectively; fractions S1, S2?and S2IV?showed an EC50?greater than 500 μg/ml.