摘要:Two highly potent cytotoxic 26-membered macrolides, isocaribenolide-I ( 1 ) and a chlorohydrin 2 , together with known amphidinolide N ( 3 ), have been isolated from a free-swimming dinoflagellate Amphidinium species (KCA09053 and KCA09056 strains) collected off Iriomote Island, Japan. The structures of 1 and 2 were determined to be a congener of 3 with an isobutyl terminus and the chlorohydrin form of 3 , respectively, by detailed analyses of spectroscopic data. The relative stereochemistries of 1 and 2 were elucidated by the conformational analyses based on NMR data.