Four new ursane‐type saponins from Morina nepalensis var. alba

Abstract

AbstractFour new ursane‐type saponins, monepalosides C–F, together with a known saponin, mazusaponin II, were isolated from Morina nepalensis var. alba Hand.‐Mazz. Their structures were determined to be 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐&[alpha;‐L‐rhamnopyranosyl‐(1 → 2)]‐α‐L‐arabinopyranosylpomolic acid 28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranoside (monepaloside C, 1), 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐&[alpha;‐L‐rhamnopyranosyl‐(1 → 2)]‐β‐D‐xylopyranosylpomolic acid 28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranoside (monepaloside D, 2), 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐&[beta;‐D‐glucopyranosy‐(1 → 2)]‐α‐L‐arabinopyranosylpomolic acid 28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranoside (monepaloside E, 3) and 3‐O‐β‐D‐xylopyranosylpomolic acid 28‐O‐β‐D‐glucopyranoside (monepaloside F, 4) on the basis of chemical and spectroscopic evidence. 2D NMR techniques, including 1H–1H COSY, HMQC, 2D HMQC‐TOCSY, HMBC and ROESY, and selective excitation experiments, including SELTOCSY and SELNOESY, were utilized in the structure elucidation and complete assignments of 1H and 13C NMR spectra. Copyright © 2002 John Wiley & Sons, Ltd.