Flavonoid glycosides from Byrsocarpus coccineus leaves. Schum and Thonn (Connaraceae)

The bioactive ethyl acetate and N-butanol soluble parts of an ethanolic extract of Byrsocarpus coccineus leaves was subjected to column chromatography over silica gel G (60-120 microns) and repeated purification of the flavonoid rich fraction over sephadex LH-20 eluted with methanol led to the isolation of three flavonoid glycosides identified as quercetin 3-O-alpha-arabinoside (I), quercetin (II) and quercetin 3-beta-D-glucoside. Their structures were elucidated by (1)H and (13)C-NMR data and are reported here for the first time in this plant.