Cytotoxic Cembranoids from the Soft Corals Sinularia gibberosa and Sarcophyton trocheliophorum

Four new cytotoxic cembranoid diterpenes, 11,12-epoxy-1( E ),3( E ),7( E)- cembratrien-15-ol ( 1 ), 3,4:11,12-diepoxy-15-methoxy-1( E ),7( E )-cembradiene ( 2 ), 1( E ),3( E ),7( E), 11( E)- cembratetraene-14,15-diol ( 3 ), and 3,14-epoxy-1( E ),7( E), 11( E )-cembratriene-4,15-diol ( 4 ), have been isolated from the soft coral Sinularia gibberosa. Selective cytotoxicity was also observed for the new compound, 7β,8α-dihydroxydeepoxysarcophine ( 5 ), and for sarcophine ( 6 ), and 16-deoxysarcophine ( 7 ), isolated from the soft coral Sarcophyton trocheliophorum. The structures of the new compounds were determined by spectral and chemical methods.