Triterpenoid saponins from the root of Anemone tomentosa

Three new triterpenoid saponins, tomentoside A (1), B (2) and C (3), along with four known saponins (4-7) were isolated from the root of Anemone tomentosa. The structures of the new compounds were elucidated as 3-O-β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (1), 3-O-β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-xylopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (2) and 3-O-β-D-galactopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (3) on the basis of chemical and spectral evidence. In the oligosaccharide chains of compound 3, the characteristic D-galactose residue is a rare structural feature and secondly encountered among triterpenoid saponins from Anemone.