Triterpenoid saponins from Anemone tetrasepala

From methanol extracts of the whole plants of Anemone tetrasepala Royle, a new triterpenoid saponin, named tetrasepaloside (1), along with oleanolic acid 3-O-alpha -gluccopyranosyl (1 -->2)-alpha -arabinoside (2), HN-saponin F (3), pulsatiloside C (4), akebia saponin D (5), cauloside D (6), ciwujianoside A(1)(7) and cauloside F (8), was isolated. By means of chemical degradation and spectral analysis, including 2D-NMR spectroscopic methods (H-1-(HCOSY)-H-1, HMBC and HMQC), the structure of 1 was elucidated as 23-O-(2 ' ,3 ' -monoacetonide)-alpha -ribofuranosyl-hederagenin-28-O-alpha -rhamnopyranosyl( 1 -->4)-beta -glucopyranosyl( 1 -->6)-beta -gulcopyranoside. All these compounds were reported for the first time from this plant.