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 IC_（50） values being 12.7 and 8.3 μmol·L~（-1）, respectively.