Isosarcophytoxide Derivatives with a 2,5-Dihydrofuran Moiety from the Soft Coral Sarcophyton cinereum .

The present chemical investigation on the organic extract of the soft coral Sarcophyton cinereum has contributed to the isolation of four new cembranoids: 16 β - and 16 α -hydroperoxyisosarcophytoxides ( 1 and 2 ), 16 β - and 16 α -methoxyisosarcophytoxides ( 3 and 4 ), and a known cembranoid, lobocrasol ( 5 ). The structures of all isolates were elucidated by detailed spectroscopic analysis. Their structures were characterized by a 2,5-dihydrofuran moiety, of which the relative configuration was determined by DU8-based calculation for long-range coupling constants ( 4 J H,H ). The cytotoxicity and immunosuppressive activities of all isolates were evaluated in this study.