Unique Toxin Profile ofa Mediterranean Ostreopsiscf. ovataStrain: HR LC-MSnCharacterization ofOvatoxin-f, a New Palytoxin Congener.

Currently, the benthic dinoflagellate Ostreopsiscf. ovatarepresents a serious concern to humanhealth in the whole Mediterranean basin due to the production of palytoxincongeners, a putative palytoxin and ovatoxins (ovatoxin-a, -b, -c,-d/-e), listed among the most potent marine toxins. High resolutionliquid chromatography–mass spectrometry (HR LC-MS) based investigationof a North Western Adriatic strain of Ostreopsiscf. ovatacollected at Portonovo (Italy) in 2008 is reportedherein. Toxin profile was different from those previously reportedfor other O.cf. ovata, both qualitativelyand quantitatively. For the first time, ovatoxin-a did not dominatethe toxin profile, and a new palytoxin congener, here named ovatoxin-f,was detected. Ovatoxin-f and its elemental formula present C2H4more than ovatoxin-a. HR CID MSnexperimentsallowed us to restrict structural differences between ovatoxin-a and-f to the region between C-95 and C-102, a region not previously beendescribed to be modified in other palytoxins. Ovatoxin-f representsthe major component of the toxin profile of the analyzed strain accountingfor 50% of the total toxin content, while ovatoxin-a, the dominanttoxin in most of the Mediterranean O.cf. ovatastrains we have analyzed so far, is the second majorcomponent of the toxin profile (23%). Thus, the presence of ovatoxin-fshould be taken into account when monitoring programs for palytoxin-likecompounds in microalgae and/or seawater are carried out. [ABSTRACT FROM AUTHOR]