Identification of the okadaic acid‐based toxin profile of a marine dinoflagellate strain P rorocentrum lima by LC – MS / MS and NMR spectroscopic data

The marine dinoflagellate P rorocentrum lima can produce toxins of okadaic acid and its congeners, which are mainly responsible for diarrhetic shellfish poisoning syndrome. Since 1990s, cells of P . lima have been reported as epiphytes to seaweeds distributed along the coast of H ainan I sland. However, its toxin profile has not hitherto been investigated. We report herein the first description and unequivocal evidence of diarrhetic shellfish poisoning toxin production in a cultured strain of P . lima isolated from the coast of S anya, H ainan I sland. Okadaic acid and its two longest diol esters, viz. okadaic acid‐ D 10a and okadaic acid‐ D 10b, have been characterized as the main diarrhetic shellfish poisoning toxin congeners of this strain by liquid chromatography–tandem mass spectrometry and NMR spectroscopic data. Okadaic acid‐ D 10a and okadaic acid‐ D 10b are first identified by NMR spectroscopic data from the dinoflagellate P . lima . The simultaneous presence of okadaic acid‐ D 10a and okadaic acid‐ D 10b in P . lima enlarges the range of target molecules that must be considered in future diarrhetic shellfish poisoning monitoring programs of H ainan I sland, C hina.