1992 Volume 40 Issue 9 Pages 2469-2472
Fresh bulbs of Ornithogalum saundersiae were found to contain five new polyhydroxylated cholestane glycosides.Their structures were ditermined to be (22S)-cholest-5-ene-3β, 11β, 16β, 22-tetrol 16-O-α-L-rhamnopyranoside (1) and its acetyl derivatives (2 and 3), and (22S)-cholesta-5, 24-diene-3β, 11β, 16β, 22-tetrol 16-O-α-L-rhamnopyranoside (4) and its acetyl derivative (5) using spectroscopic analysis and chemical correlations. Determination of the absolute configuration at the C-22 hydroxyl position of 1 was achieved by the application of the advenced Mosher's method to the aglycon (1a) of 1, and those of 2-5 by correlating them to 1. The cholestane glycosides with an acetyl group at the C-3 hydroxyl position of the rhamnose showed potent inhibitory activity on cyclic adenosine monophosphate (AMP) phosphodiesterase.
