Identification of 24-O-β-d-Glycosides and 7-Deoxy-Analogues of Okadaic Acid and Dinophysistoxin-1 and -2 in Extracts from Dinophysis Blooms, Dinophysis and Prorocentrum Cultures, and Shellfish in Europe, North America and Australasia

Abstract

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.

A survey ofDinophysisspp. and their potential to cause diarrhetic shellfish poisoning in coastal waters of the United States

“…Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis, based on the method of Wilkins et al (2021), was conducted in positive mode with a Q Exactive-HF Orbitrap mass spectrometer equipped with a HESI-II heated electrospray ionization interface (Thermo Fisher Scientific) with an Agilent 1200 G1312B binary pump, G1367C autosampler (tray set to 10°C), and G1316B column oven (Agilent Technologies). Analyses were performed with a Symmetry Shield RP18 column (3.5 μm, 100 × 2.1 mm; Waters) at 20°C, with mobile phases A and B of H 2 O and MeCN, respectively, each of which contained formic acid (0.1% v/v).…”

Marine natural products

“…Their presence was observed in contaminated shellfish from Spain, Norway, Canada, Ireland and New Zealand. 335 Two new amphidinolide N congeners 874 and 875 are potent cytotoxins isolated from Amphidinium sp. 336 A report of three new amphidiniols 876–878 has suggested that centrifugation to clarify the culture media is a stressor that prompts release of the compounds from the dinoflagellate into the surrounding liquid.…”