Tricycloclavulone and clavubicyclone, novel prostanoid-related marine oxylipins, isolated from the Okinawan soft coral Clavularia viridis

Two novel prostanoid-related marine oxylipins, tricycloclavulone (1) and clavubicyclone (2), were isolated from the Okinawan soft coral Clavularia viridis. The structures of 1, having a tricyclo[5.3.0.0(1,4)] decane ring system, and 2, having a bicyclo [3.2.1] octane ring system, were elucidated on the basis of spectroscopic analysis. Clavubicyclone showed a moderate growth inhibition activity against tumor cells in vitro.