Casbane Diterpenes from Red Sea Coral Sinularia polydactyla

The soft coral genus Sinularia is a rich source of bioactive metabolites containing a diverse array of chemical structures. A solvent extract of Sinularia polydactyla resulted in the isolation of three new casbane diterpenes: sinularcasbane M (1), sinularcasbane N (2) and sinularcasbane O (3); in addition, known metabolites (4-5) were isolated. Compounds were elucidated on the basis of spectroscopic analyses; the absolute configuration was confirmed by X-ray analysis.