Studies on nepalese crude drugs. III. On the saponins of Hedera nepalensis K. Koch.
Abstract
Twelve saponins, tentatively named HN-saponins A (I), B (II), D1 (III), D2 (IV), E (V), F (VI), H (VII), I (VIII), K (X), M (XII), N (XIII) and P (XIV), were isolated from the stem and bark of Hedera nepalensis K. KOCH. (Araliaceae). Compounds II, V, XII, XIII and XIV were identified as Kizuta saponins K3, K6, K10, K11 and K12, respectively, which have been isolated from Hedera rhombea BEAN. On the basis of chemical and physicochemical evidence, other saponins were identified as follows : I, a mixture of the β-D-glucopyranosides of campesterol (trace), stigmasterol and β-sitosterol ; III, hederagenin 3-O-β-D-glucopyranoside ; IV, oleanolic acid 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside ; VI, 3-O-α-L-arabinopyranosyl-hederagenin 28-O-β-D-glucopyranosyl ester ; VII, hederagenin 28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester ; VIII, oleanolic acid 3-O-β-D-glucuronopyranoside ; X, hederagenin 3-O-β-D-glucuronopyranoside. Compounds VI and VII were isolated from nature for the first time, though they had previously been derived from Akebia seed saponin D and Kizuta saponin K12, respectively, by partial hydrolysis.