Triterpenoid Saponins from the Spikes of Prunella vulgaris

Three new oleanane‐skeleton triterpenoid saponins, 3 β ,4 β ,16 α ‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl 4‐ O‐β ‐ D ‐xylopyranosyl‐ β ‐ D ‐glucopyranosiduronic acid ( 1 ), (3 β ,4 β ,16 α )‐17‐carboxy‐16,24‐dihydroxy‐28‐norolean‐12‐en‐3‐yl β ‐ D ‐glucopyranosiduronic acid methyl ester ( 2 ), and (3 β ,4 β )‐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.