High resolution LC-MS study of ovatoxins produced by Ostreopsis ovata

In the last decades, the recurring presence of the benthic dinoflagellate Ostreopsis ovata has caused severe sanitary emergencies and economic losses along the whole Italian coastline. Liquid chromatography-mass spectrometry (LC-MS) technique played a key role in revealing the presence of putative palytoxin and much higher amounts of ovatoxin-a, a palytoxin-like compound, in field samples of O. ovata. In our ongoing research on O. ovata toxins we report herein on high resolution LC-MS and MS2 investigation of O. ovata cultures, which disclosed the occurrence of several new ovatoxins in algal extracts. Elemental formulae very close to palytoxin???s were assigned to the new compounds and information was gained about their structural features. A quantitative study of several O. ovata culture extracts indicated that ovatoxin-a generally represents the major component of the algal toxin profile and that the whole of the other ovatoxins constitutes up to 46% of the total toxin content of the analyzed strains; thus, their presence should be taken into account when LC-MS based monitoring programs of either plankton or contaminated seafood are carried out.