Oleanane Saponins from Rhizome of Anemone raddeana

Two new oleanolic acid-type triterpenoid saponins, raddeanosides R-22 and R-23 (1 and 2, resp.), together with four known saponins were isolated from the rhizome of Anemone raddeana REGEL. The structures of the new compounds were elucidated as oleanolic acid 3-O-beta-D-glucopyranosyl(1 -> 2)[beta-D-glucopyranosyl(1 -> 4)]-alpha-L-arabinopyranoside (1) and oleanolic acid 3-O-alpha-L-arabinopyranosyl(1 -> 3)-alpha-L-rhamnopyranosyl(1 -> 2)[beta-D-glucopyranosyl(1 -> 4)]-alpha-L-arabinopyranoside (2). The four known compounds were identified as oleanolic acid 3-O-alpha-L-arabinopyranoside (3), oleanolic acid 3-O-beta-D-glucopyranosyl(1 -> 4)-alpha-L-arabinopyranoside (4), hederasaponin B (5), and hederacholchiside E (6) on the basis of chemical and spectral evidences. Compound 4 is reported for the first time from the Anemone genus, while the other three known compounds have been already found in this plant.