Triterpenoid Saponins from the Spikes of Prunella vulgaris

Abstract Three new oleanane‐skeleton triterpenoid saponins, 3β,4β,16α‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D‐xylopyranosyl‐β‐D‐glucopyranosiduronic acid (1), (3β,4β,16α)‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl β‐D‐glucopyranosiduronic acid methyl ester (2), and (3β,4β)‐24‐hydroxy‐16‐oxo‐28‐norolean‐12‐en‐3‐yl 4‐O‐β‐D‐xylopyranosyl‐β‐D‐glucopyranosiduronic acid (3), together with eight known constituents, i.e., the oleanane‐type triterpenoids 4–6, and the ursane‐type triterpenoids 7–11, were isolated from the spikes of Prunella vulgaris. The new structures were established by means of detailed spectroscopic analysis (IR, HR‐ESI‐MS, 1D‐ and 2D‐NMR experiments). Compounds 1–3 were tested for their inhibition activity against the growth of tumor cell lines; only compound 3 displayed marginal inhibition activity.