Marine sterols. XVII. Polyhydroxysterols of the soft corals of the andaman and nicobar coasts. (2). Isolation and atructures of three 16.BETA.-hydroxy steroidal glycosides from an Alcyonium sp. soft coral.
3β, 7β-Dihydroxy-24-methylenecholesterol (1) and three new polyhydroxysterol glycosides (2a, 3a and 4) were isolated from the lipid extract of an Alcyonium sp. soft coral which was collected in the Andaman and Nicobar Islands. Isolation of steroidal glycosides from soft corals is rare, if not unprecedented. Spectroscopic and chemical degradation studies indicated the new glycosides to be 24-methylenecholest-5-ene-3β, 16β-diol-3-O-α-L-fucoside (2a) and its 7β- (3a) and 7α-hydroxy (4) derivatives.