Studies on the chemical constituents of the algae Sargassum polycystcum

Three compounds have been isolated from the algae Sargassum polycystcum collected from the North China Sea. Their structures were established as stigmast-5,23,25-triene (1), 3-pentacosox-1,2-propanediol 2 (2), 24xi-methyleholestane-3beta,5alpha,6beta,25-tetrol-25-acetate (3) by MS, IR, D-1 NMR, D-2 NMR and elemental analysis. Compound 1 is a previously unknown compound.