New steroidal constituents from the bulbs of Lilium candidum

Eight spirostanol saponins, including four new compounds, and two known furostanol saponins were isolated from the fresh bulbs of Lilium candidum. The structures of new compounds were determined to be (25R,26R)-26-methoxyspirost-5-ene-3 beta,17 alpha-diol 3-O-?O-alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->4)] -beta-D-glucopyranoside?, (25R,26R)-26-methoxyspirost-5-ene-3 beta,17 alpha-diol 3-O-?O-alpha-L-rhamnopyranosyl-(1-->2)-O-6-O-acetyl-beta-D-glucopyranos yl- (1-->4)]-beta-D-glucopyranoside?, (25R,26R)-26-methoxyspirost-5-ene-3 beta,17 alpha-diol 3-O-?O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside? and (25S)-spirost-5-ene-3 beta,27-diol 3-O-?O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)-O - beta-D-glucopyranosyl-(1-->4)]-beta-D-glucopyranoside?, respectively, on the basis of spectroscopic analysis, including two-dimensional NMR techniques, and the result of hydrolysis. The inhibitory activity of the isolated saponins on Na+/K+ ATPase was evaluated.