Two new triterpenoid saponins from Akebia quinata (Thunb.) Decne

Two new triterpenoid saponins, hederagenin 3-O-α-L-arabinopyranosyl-(1→2)-α-L-arabinopyranoside named akeboside L_a (compound 1), oleanolic acid 3-O-α-L-arabinopyranosyl-(1→2)-(β-D-glucopyranoside named akeboside L_b (compound 2), along with five known saponins, oleanolic acid 3-O-α-L-rhamnopyranosyl- (1→2)-α-L-arabinopyranoside (compound 3), hederagenin 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (compound 4), oleanolic acid 3-O-β-D-xylopyranosyl-(1→3)- α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (compound 5), 3-O-α-L-rhamnopyranosyl-(1→2)-α-L- arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl- (1→4)-α-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (compound 6), 3-O-α-L-rhamnopyranosyl-(1→2)-α-L- arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl-(1→4)- β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (compound 7) were isolated from the n-butanol part of the 80% ethanol extracts of the dried stems of Akebia quinata (Thunb.) Decne. Compound 5 was isolated from plants of genus Akebia for the first time. The structures were elucidated on the basis of physicochemical properties and spectral data.