Novel triterpene saponins isolated from Clematis mandshurica and their inhibitory activities on NO production

Four new triterpene saponins, mandshunosides F-I (1-4), together with five known compounds (5-9), were isolated from the roots and rhizomes of Clematis mandshurica. Their structures were elucidated on the basis of spectroscopic evidences and hydrolysis products. Bisdesmosidic saponin (3-9) showed modest suppression of NO production with the inhibition ratios in the range of 51.3%- 64.6% at 50 μmol·L−1, whereas monodesmosidic saponins with a free carboxyl group at C-28 (1 and 2) showed potent inhibitory activities with IC50 values being 12.7 and 8.3 μmol·L−1, respectively.