Natural Products from the Gorgonian Lophogorgia punicea: Isolation and Struture Elucidation of an Unusual 17-Hydroxy Sterol

The natural products chemistry of the gorgonian Lophogorgia punicea, collected on the Southeast Brazilian coast, were investigated for the first time. Gas chromatography - mass spectral analysis of the monohydroxylated sterol mixture revealed the presence of nine common C26 to C29 cholestane derivatives. A detailed study of the crude extract of Lophogorgia punicea led to the isolation of hydroquinone and a new polyhydroxylated sterol named punicin (1). The structure of punicin was determined by interpretation of spectral data including 2D NMR and HRFABMS. Punicin is an unprecedented sterol possessing a C-17 hydroxyl group, a feature uncommon in marine organisms.