Hurgadacin: a new steroid from Sinularia polydactyla.

Hurgadacin (1), a 24,25-bishomo-26-methylenecholesterol was isolated from the soft coral Sinularia polydactyla, collected from the Red Sea, near Hurghada at the Egyptian coast. The new steroid 1 was isolated together with the closely related polyhydroxy steroids 24-methylenecholestane-3β,5α,6β-triol (2) and 24-methylenecholestane-1α,3β,5α,6β,11α-pentol (3), in addition to the sesquiterpene lactiflorenol (4) and the trinorcarotenolide acetate peridinin (5), The structures of the isolated compounds were confirmed by intensive studies of their 1D and 2D NMR spectra and mass data. The antimicrobial and cytotoxic activities of the soft coral extract and the corresponding constituents were evaluated against diverse pathogenic microorganisms and brine shrimps, respectively.