Identification of Pinnatoxins and Discovery of Their Fatty Acid Ester Metabolites in Mussels (Mytilus edulis) from Eastern Canada

Abstract

Pinnatoxins are a group of fast-acting cyclic imine toxins previously identified in shellfish from Asia, the southern Pacific, and northern Europe. In this work pinnatoxins were detected in mussels from locations across the eastern coast of Canada. Pinnatoxin G (6) was the major structural variant present, sometimes at levels >80 μg/kg, whereas much lower levels of pinnatoxin A (1) were detected in some samples. Increased concentrations were observed following base hydrolysis of extracts, leading to the discovery by LC-MS of a range of fatty acid esters of 6. Information on the structures of these acylated derivatives was provided through a series of mass spectrometric experiments, supported by partial synthesis, and it is proposed that the compounds are 28-O-acyl esters of 6. Although acyl esters of a range of other phycotoxins are known to form as metabolites in shellfish, this is the first report of their existence for this particular toxin class. The occurrence of pinnatoxins in North American shellfish further highlights the international distribution of these toxins.

The implementation of liquid chromatography tandem mass spectrometry for the official control of lipophilic toxins in seafood: Single-laboratory validation under four chromatographic conditions

“…Matrix effects may explain deviations in recovery, a problem often reported in lipophilic toxin determination by LC-MS/MS [17,[21][22][23][24][25]. Signal suppression of AZA1, SPX1 and GYMA under pH 2 could explain the low recovery of these toxins, while OA signal enhancement correlated with the overestimation of OA in mussels and sea urchin.…”

“…McCarron et al [25] also highlighted the importance of finding a proper matrix to be used as a match in the MMS strategy.…”

“…Besides MMS, other groups have proposed several techniques to compensate matrix effects: solid phase extraction (SPE) clean-up [22,24], optimization of the chromatographic method [24], selection of the appropriate instrumentation [21,24], sample dilution [21], and standard addition [23,25]. All techniques their disadvantages, mostly related to the additional time and amount of standards needed, thus the selection of a proper strategy to deal with matrix effects is not trivial.…”

The first report ofVulcanodinium rugosum(Dinophyceae) from the South China Sea with a focus on the life cycle

“…Pinnatoxins EÁG were detected in shellfish from northern New Zealand and South Australia (McNabb et al 2008;Selwood et al 2010). The discovery of pinnatoxin G in Norwegian and Canadian mussels suggested an international distribution of this toxin (Rundberget et al 2011;McCarron et al 2012). Pinnatoxins have been circumstantially linked to shellfish poisoning events but have not proven to be toxic to humans, although they are toxic to mice Rhodes et al 2011a).…”

Spirolides and Cyclic Imines: Toxicological Profile

“…Recently, a new pinnatoxin analogue, pinnatoxin H, was purified from a culture of the dinoflagellate Vulcanodinium rugosum from the South China Sea (Selwood et al 2014). It is worth noting that the fatty acid esters of pinnatoxins A and G isolated from Canadian mussels were reported to likely originate from the shellfish than from the dinoflagellate (McCarron et al 2012). Similarly, there is no conclusive evidence for the dinoflagellate source of pteriatoxins, isolated from the Japanese bivalve Pteria penguin (Shumway 1990).…”