Antifouling activity of terpenoids from the corals Sinularia flexibilis and Muricella sp. against the bryozoan Bugula neritina .

Marine natural products are promising sources of green antifoulants. Here, a new compound () was isolated from the soft coral . This compound, another nine cembranoids (-) from , and three eunicellin-type diterpenoids (-) from the gorgonian sp. were tested for antifouling activity against larval settlement of the bryozoan . Compounds , , , , , and exhibited significant antifouling activity, with EC values of 18.2, 99.7, 67.9, 35.6, 33.9, and 49.3 μM, respectively. Analysis of the structure-activity relationships suggested that the hydroxy group at C-13 in compound reduced its antifouling activity.