Pavidolides A-E, new cembranoids from the soft coral Sinularia pavida

Five new cembrane-based diterpenoids, namely pavidolides A-E (1-5) were isolated from the marine soft coral Sinularia pavida, together with sarcophytin and chatancin. The structures of new compounds were determined on the basis of extensive spectroscopic data analysis. Pavidolide B (2) possesses an unprecedented 6,5,7-tricarbocyclic nucleus, whereas pavidolide C (3) is characteristic of an unusual C-5 and C-9 conjuncted cembranoid. Pavidolides C and D showed moderate antifouling activity against the larval settlement of barnacle Balanus amphitrite, while pavidolides B and C exhibited inhibitory activity against the human leukemia cell line HL-60.