Characterisation of multiple Caribbean ciguatoxins and congeners in individual specimens of horse-eye jack (Caranx latus) by high-performance liquid chromatography/mass spectrometry.
We studied the variation in toxin profiles of purified extracts of 10 individual specimens and two pools of ciguateric Caranx latus. High-performance liquid chromatography/mass spectrometry (HPLC/MS) identified in all individual samples at least seven Caribbean ciguatoxins (C-CTXs) comprising C-CTX-1 and its epimer C-CTX-2 ([M+H](+) m/z 1141.58), and five new C-CTX congeners with pseudo-molecular ions at m/z 1141.58, 1143.60, 1157.57, 1159.58, and 1127.57. In some samples, additional C-CTX isomers were detected with [M+H](+) ions at m/z 1141.58 (two), 1143.60 (one) and 1157.57 (two). The two low-toxic pools contained only four to six ciguatoxins. The comparison in relative proportions of four different mass classes ([M+H](+) at m/z 1141, 1143, 1157 and 1127) showed that the group at m/z 1157 increased (2-20%) with flesh toxicity. More than 80% of group m/z 1141 comprised C-CTX-1, C-CTX-2 and their isomer C-CTX-1a whose level in this group correlated with fish toxicity. Contrary to low-toxic fishes, high-risk specimens had C-CTX-1 levels <50% and were subjected to large losses of activity on purification indicating that unstable ciguatoxins were present. A possible conversion of C-CTX-1 into C-CTX-1a was identified when flesh was cooked, without changes in toxicity. In conclusion, HPLC/MS characterised 12 C-CTXs accumulated by C. latus at variable levels.
Pottier
Ivannah
I
Laboratoire de Microbiologie Alimentaire, Universite de Caen, Esplanade de la Paix, 14032 Caen cedex, France.
Vernoux
Jean-Paul
JP
Jones
Alun
A
Lewis
Richard J
RJ
D000818:Animals; D001267:Atlantic Ocean; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002922:Ciguatoxins / Q000145:classification / Q000302:isolation & purification* / Q000633:toxicity; D005400:Fishes, Poisonous / Q000378:metabolism*; D005517:Foodborne Diseases; D008297:Male; D051379:Mice; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D002922:Ciguatoxins