New C-glycosylflavones from Tetrastigma hemsleyanum (Vitaceae)

Two novel C-glycosylflavones, apigenin-6-C-α-L-arabinopyranosyl-(1-4)- α-L-rhamnopyranoside (hemsleyanoside, 1) and apigenin-8-C-α-L- arabinopyranosyl-(1-4)-α-L-rhamno-pyranoside (isohems-leyanoside, 2), together with a known compound (apigenin-6,8-di-C-β-D-glucopyranoside, 3), were isolated from the 95% EtOH extract of Tetrastigma hemsleyanum Diels et Gilg. Their structures were elucidated by chemical evidence and spectral analysis.