Simple structural elucidation of ostreocin-B, a new palytoxin congener isolated from the marine dinoflagellate Ostreopsis siamensis, using complementary positive and negative ion liquid chromatography/quadrupole time-of-flight mass spectrometry.

The planar structure of ostreocin-B is assigned to 42-hydroxy-3,26-didemethyl-19-deoxypalytoxin (=44-hydroxyostreocin-D). The method used in this study is an excellent tool to obtain structural information on interspecies and intrastrain variation of palytoxin congeners in marine organisms.