STEROIDAL SAPONINS FROM THE BULBS OF LILIUM-SPECIOSUM X L-NOBILISSIMUM STAR-GAZER AND THEIR ANTITUMOR-PROMOTER ACTIVITY

The fresh bulbs of the oriental hybrid lily, Lilium speciosum x L. nob ilissimum 'Star Gazer' yielded a new steroidal saponin, (25R,26R)-26-m ethoxyspirost-5-en-3 beta-ol D-glucopyranosyl-(1-->4)]-beta-D-glucopyr anoside}, along with four known steroidal saponins, (25R,26R)-26-metho xyspirost-5-en-3 beta-ol L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranos ide}, (25R,26R)-26-methoxyspirost-5-en-3 beta-ol D-glucopyranosyl-(1-- >4)]-beta-D-glucopyranoside}, O-[(S)-3-hydroxy-3-methylglutaryl]-spiro st-5-ene-3 beta,27-diol -L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranos ide} and O-[(S)-3-hydroxy-3-methylglutaryl]-spirost-5-ene-3 beta,27-di ol 3-O-{O-alpha-L-rhamnopyranosyl-(1 D-glucopyranosyl-(1-->4)]-beta-D- glucopyranoside}. The structure of the new saponin was determined by m eans of spectroscopic analysis and hydrolysis. The methyl ester of 5 s howed potent inhibitory activity on 12-O-tetradecanoylphorbol-13-aceta te (TPA)-stimulated P-32 incorporation into phospholipids of HeLa cell s.