Cembranoids from the soft coral Sinularia rigida with antifouling activities.

Chemical examination of the soft coral Sinularia rigida resulted in the isolation of 12 new cembranoids, namely, sinulariols T-Z5 (1-12), together with a known analogue, 13. Their structures were determined on the basis of 1D and 2D NMR (COSY, HSQC, HMBC, and NOESY) spectroscopic analyses in association with MS and IR data. Compounds 7 and 13 showed potent antifouling activity for the inhibition against the barnacle Balanus amphitrite and moderate inhibition against Bugula neritina . The primary structure-activity relationship is discussed.