Determination of the contents of total polyphenols, total flavonoids and tannins in young, unopened leaves of Piliostigma thonningii (Caesalpiniaceae)

Abstract

The young, unopened leaves of Piliostigma thonningii are specifically used by traditional practitioners in Côte d'Ivoire for the treatment of various pathologies. The present study aimed to determine the contents of total polyphenols, flavonoids and condensed tannins of extracts and fractions of these young, unopened leaves. Their secondary metabolites were extracted by maceration in an ethanol-water mixture (70/30: v / v) with a yield of 36%. The successive fractionation of the hydroalcoholic extract obtained by hexane, dichloromethane, ethyl acetate, ethanol and water gave yields varying from 5.55 to 33.33%. The determination of total polyphenols, total flavonoids and condensed tannins gave contents varying between 0.23 ± 0.05 and 146.67 ± 4.25 mg EAG / g of dry extract, between 5.33 ± 0.62 and 112.11 ± 0.83 mg EQ / g of dry extract and between 23.33 ± 0.94 et 38.33 ± 0.47 mg EAT/g of dry extract respectively. In general, the hydroalcoholic extract and the ethyl acetate fraction are the richest in secondary metabolites, polyphenols, flavonoids and condensed tannins.