Saponins from Cussonia bancoensis and their inhibitory effects on nitric oxide production

Two new triterpenoid saponins (1 and 2) were isolated from the stem bark of Cussonia bancoensis together with the known stigmasterol, ursolic acid, 23-hydroxyursolic acid (3), and 3beta-hydroxylup-20(29)-en-28-oic acid. On the basis of their spectroscopic data and on chemical transformations, the structures of the new saponins have been established as 3-O-(alpha-L-arabinopyranosyl)-23-hydroxyursolic acid (1) and 3-O-(beta-D-glucopyranosyl)-23-hydroxyursolic acid (2). In a nitric oxide (NO)-production bioassay, compound 3 exhibited significant NO inhibitory activity, while compounds 1 and 2 were less potent than 3.