Search

Two high-mass polar compounds were observed in aqueous side-fractions from the purification of okadaic acid ( 1 ) and dinophysistoxin-2 ( 2 ) from Dinophysis blooms in Spain and Norway. These were isolated and shown to be 24- O -β-d-glucosides of 1 and 2 ( 4 and 5 , respectively) by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and enzymatic hydrolysis. These, together with standards of 1 , 2 , dinophysistoxin-1 ( 3 ), and a synthetic specimen of 7-deoxy- 1 ( 7 ), combined with an understanding of their mass spectrometric fragmentation patterns, were then used to identify 1 - 5 , the 24- O -β-d-glucoside of dinophysistoxin-1 ( 6 ), 7 , 7-deoxy- 2 ( 8 ), and 7-deoxy- 3 ( 9 ) in a range of extracts from Dinophysis blooms, Dinophysis cultures, and contaminated shellfish from Spain, Norway, Ireland, Canada, and New Zealand. A range of Prorocentrum   lima cultures was also examined by liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) and was found to contain 1 , 3 , 7 , and 9 . However, although 4 - 6 were not detected in these cultures, low levels of putative glycosides with the same exact masses as 4 and 6 were present. The potential implications of these findings for the toxicology, metabolism, and biosynthesis of the okadaic acid group of marine biotoxins are briefly discussed.