Furanocembranoid from the Okinawan soft coral Sinularia sp.

One new furanocembranoid diterpene, 11-hydroxy-Δ-pukalide (1), along with six known secondary metabolites, 11-acetoxy-Δ-pukalide (2), 13α-acetoxypukalide (3), pukalide (4), 3α-methoxyfuranocembranoid (5), Δ-africanene (6), and methyl (5'E)-5-(2',6'-dimethylocta-5',7'-dienyl)furan-3-carboxylate (7) were isolated from the Okinawan soft coral Sinularia sp. Their chemical structures were elucidated based on spectroscopic analysis (FTIR, NMR, and HRESIMS), and the relative stereochemistry of 1 was determined by NOESY experiments and acetylation, which yielded derivative 2. In addition, compounds 1 and 7 exhibited toxicity in the brine shrimp lethality test.