TIGOGENIN HEXASACCHARIDES FROM CAMASSIA-CUSICKII - STRUCTURAL ELUCIDATION BY MODERN NMR TECHNIQUES

Two steroidal saponins containing six carbohydrate residues have been isolated from the bulbs of Camassia cusickii. Their structures were determined by modern NMR techniques, H-1 H-1 COSY, HOHAHA, H-1 - C-13 COSY, and HMBC spectra to be (25R)-5-alpha-spirostan-3-beta-yl 4-O-[2-O-[3-)-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyl]-3-O-[4-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyl]-beta-D-glucopyranosyl]-beta-D-galactopyranoside (1) and (25R)-5-alpha-spirostan-3-beta-yl 4-O-[2-O-[3-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosyl]-3-O-[4-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyl]-beta-d-glucopyra nosyl]-beta-D-galactopyranoside (2), respectively. Compound 1 showed inhibitory activity on cyclic AMP phosphodiesterase.