Asteryunnanosides F and G: two new triterpenoid saponins from Aster yunnanensis

Two new triterpenoid saponins, aster-yunnanosides F and G, were isolated from the roots of Aster-yunnanensis. Their structures were determined as oleanolic acid-28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside and 3-O-beta-glucopyranosyloleanolic acid-28-O-beta-D-glucopyranosyl-(1-->6)-[alpha-L-rhamnopyranosyl-(1-->2) ]- beta-D-glucopyranoside by spectral data, especially 2D NMR analysis including COSY, HETCOR, HOHAHA, and ROESY techniques, and chemical transformation.