A new ursane-type triterpene oxoglucopyranoside from Crossopteryx febrifuga.

A new saponin, 3-O-beta-D-3-oxo-glucopyranosylursa-12,20(30)-diene-27,28-dioic acid (1), was isolated from the methanol extract of stem bark of Crossopteryx febrifuga together with the known 313-D-glucopyranosyl-ursa-12,20(30)-diene-27,28-dioic acid (2), shanzhiside methyl ester (3), shanzhiside (4), beta-sitosterol (5), beta-sitosterol-30-beta-n-glucopyranoside (6), ursa-12,20(30)-diene-27,28-dioic acid (7), hederagenin (8), and oleanolic acid (9). The structures were established by comprehensive interpretation of their spectral data 1D- (H-1 and C-13), 2D-NMR (H-1-H-1 COSY, HMQC, HMBC), spectroscopic, and electrospray ionisation time-of-flight mass spectrometry analysis. The isolated compounds and extracts were screened for their antibacterial properties. Although the EtOAc and n-BuOH extracts exhibited considerable antibacterial activity against Pseudomonas aeruginosa with minimum inhibitory concentration (MIC) value of 32 mu g/mL, compounds 2 and 8 showed moderate activity against Enterococcus faecalls with MIC values of 256 and 128 mu g/mL, respectively. The new compound (1) exhibited a moderate antibacterial activity against Staphylococcus aureus with an MIC value of 512 mu g/mL.