PHYTOCHEMICAL SCREENING AND ANTI-RADICAL SCAVENGING ACTIVITY OF THREE ANTIANAMIC PLANTS ACCLIMATED IN BENIN : Alternanthera brasiliana, Monechma depauperatum and Hibiscus acetosella

Resort to the use of plants for the treatment of human diseases including anemia is common both in Benin's urban and rural areas. The aim of this work is to identify the secondary metabolites and evaluate the anti-radical activity of the crude extracts of Alternanthera brasiliana, Monechma depauperatum and Hibiscus acetosella, three plants used in traditional medicine in Benin for several diseases including anemia. By complexion and/ or precipitation reactions, the different groups of secondary metabolites in these plants were highlighted. The content of polyphenolic compounds was determined by the Folin-Ciocalteu method for phenolic compounds, aluminum trichloride (AlCl3) for total flavonoids and sulfuric vanillin for condensed tannins. The scavenging activity was evaluated by the DPPH method and the hydroxyl radical method. Phytochemical analysis reveal the presence of gallic tannins, saponins, terpens and sterols. The absence of coumarins and alkaloids was noticed. The extract of H. acetosella has the highest anti-radical scavenging activity. This activity is correlated with the content of phenolic compounds that are flavonoids, tannins and phenolic acids. The richness in secondary metabolites extracted and the high content of phenolic compounds responsible of anti-radical activity can justify the use of these plants against anemia whose pathophysiology involves oxidative stress.