Nortriterpene Saponins from Akebia trifoliate

Three new nortriterpene saponins, 2α,3β,20α-trihydroxy-30-norolean-12-en-28-oic acid O-β-D-xylopyranosyl-(1-->3)-α-L-rhamnopyranosyl-(1-->4)-β-D- glucopyranosyl-(1-->6)-β-D-glucopyranosyl ester (3), 2α,3β,20α-trihydroxy-30-norolean-12-en-28-oic acid O-α-L-rhamnopyranosyl-(1-->4)-β-D- glucopyranosyl-(1-->6)-β-D-glucopyranosyl ester (4), and 2α,3β,23-trihydroxy-30-noroleana-12,19-dien-28-oic acid O-β-D-xylopyranosyl-(1-->3)-α-L- rhamnopyranosyl-(1-->4)-β-D-glucopyranosyl-(1-->6)-β-D-glucopyranosyl ester (6), were isolated from the methanol extract of the pericarps of Akebia trifoliata Koidzumi (Lardizabalaceae), together with five known nortriterpene saponins and three phenolic glycosides. Their structures were elucidated by spectroscopic analyses and acid hydrolysis.