Steroidal saponins from the bulbs of Lilium regale and L. henryi

Two new and three known steroidal saponins were isolated from the fresh bulbs of Lilium regale and two known saponins from those of L. henryi. The structures of the new saponins were established by extensive spectral data, hydrolysis and chemical correlation as (25R)-27-O-[(S)-3-hydroxy-3-methylglutaroyl]-spirost-5 -ene-3 beta,27-diol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-O-[beta-D-glucopyranosyl-(1-->3)]- beta-D-glucopyranoside and (25S)-spirost-5-ene-3 beta,17 alpha,27-triol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-O-[beta-D-glucopyranosyl-(1-->2)-O- beta-D-glucopyranosyl-(1-->4)]-beta-D-glucopyranoside. Inhibitory activity of the saponins on cyclic AMP phosphodiesterase was evaluated.