Liquid Chromatography Coupled to High-Resolution Mass Spectrometry for the Confirmation of Caribbean Ciguatoxin-1 as the Main Toxin Responsible for Ciguatera Poisoning Caused by Fish from European Atlantic Coasts

Abstract

Ciguatera poisoning (CP) is a common seafood intoxication mainly caused by the consumption of fish contaminated by ciguatoxins. Recent studies showed that Caribbean ciguatoxin-1 (C-CTX1) is the main toxin causing CP through fish caught in the Northeast Atlantic, e.g., Canary Islands (Spain) and Madeira (Portugal). The use of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) combined with neuroblastoma cell assay (N2a) allowed the initial confirmation of the presence of C-CTX1 in contaminated fish samples from the abovementioned areas, nevertheless the lack of commercially available reference materials for these particular ciguatoxin (CTX) analogues has been a major limitation to progress research. The EuroCigua project allowed the preparation of C-CTX1 laboratory reference material (LRM) from fish species (Seriola fasciata) from the Madeira archipelago (Portugal). This reference material was used to implement a liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) for the detection of C-CTX1, acquisition of full-scan as well as collision-induced mass spectra of this particular analogue. Fragmentation pathways were proposed based on fragments obtained. The optimized LC-HRMS method was then applied to confirm C-CTX1 in fish (Bodianus scrofa) caught in the Selvagens Islands (Portugal).Key Contribution: LC-Q-TOF-MS in full-scan MS and MS/MS mode permitted successful acquisition of C-CTX1 spectra. Fragmentation pathways are presented. C-CTX1 was confirmed in a barred hogfish (Bodianus scrofa) from the Selvagens Islands (Portugal).

An Update on Ciguatoxins and CTX-like Toxicity in Fish from Different Trophic Levels of the Selvagens Islands (NE Atlantic, Madeira, Portugal)

“…These levels are among the highest determined in Macaronesia and exceeds the U.S. Food and Drugs Administration (FDA) guidance level of 0.1 µg C-CTX1 kg −1 . Such high levels have been of key importance to fully characterize and confirm fragmentation pathways of C-CTX1 by high resolution mass spectrometry [ 32 ].…”

Epibenthic Harmful Marine Dinoflagellates from Fuerteventura (Canary Islands), with Special Reference to the Ciguatoxin-Producing Gambierdiscus

“…G. excentricus displays the highest content of CTXs so far [23,24,50] and its CTX-like toxicity has been comparable to that of G. polynesiensis, the predominant CTX producer in the South Pacific, a ciguatera endemic region. In contrast to the consistent toxicity characteristics of G. excentricus, analyses of G. australes have yielded variable results depending on the strains and their origins [24,30,85,86]. The toxicity of the rest of Gambierdiscus species from the Canary Islands has been very scarcely studied; neuroblastoma cell-based assay (neuro-2a CBA) revealed lower CTX-like toxicity than the former ones (or even none for G. caribaeus), although high intraspecific variability has been also reported [24,30].…”

Neurological Disturbances of Ciguatera Poisoning: Clinical Features and Pathophysiological Basis

“…To achieve this goal, the development of an enzyme-linked immunoassay (ELISA) is attractive for its accuracy, sensitivity, routine and portable use, and recent progress is promising [ 18 , 19 , 20 , 21 ]. Laboratory methods such as cell-based assays and HPLC-MS(/MS) are useful to detect, quantify and/or identify CTXs after suitable extraction from fish meal remnants [ 8 , 17 , 22 , 23 , 24 , 25 , 26 , 27 ] and mammalian fluids or tissues following intoxication [ 28 , 29 , 30 ]. Chemical methods are also used in a few laboratories to purify CTXs.…”