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Structure of Caribbean Ciguatoxin Isolated from Caranx latus

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Lewis, R. J., Vernoux, J.-P. and Brereton, I. M. (1998) Structure of Caribbean Ciguatoxin Isolated from Caranx latus. Journal of the American Chemical Society, 120 (24). pp. 5914-5920. ISSN 0002-7863

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Article Link(s): https://doi.org/10.1021/ja980389e

Abstract

Caribbean ciguatoxins (C-CTXs) are responsible for the widespread occurrence of ciguatera in the Caribbean Sea. The structure and configuration of C-CTX-1 (1), the major ciguatoxin isolated from the horse-eye jack (Caranx latus), has been determined from DQF-COSY, E-COSY, TOCSY, NOESY, ROESY, ge-HSQC, and HMQC experiments performed at 750 MHz and 500 MHz on a 0.13 μmol sample. C-CTX-1 ([M + H]+ m/z 1141.6 Da, molecular formula C62H92O19) has a ciguatoxin/brevetoxin ladder structure comprising 14 trans-fused, ether-linked rings (7/6/6/7/8/9/7/6/8/6/7/6/7/6) assembled from 6 protonated fragments. The relative stereochemistry and ring configuration of 1 was determined from an analysis of coupling constant and NOE data. Like ciguatoxins in the Pacific Ocean (P-CTX), C-CTX-1 possesses a flexible nine-membered ring which may be a conserved feature among ciguatoxins. However, C-CTX-1 has a longer contiguous carbon backbone (57 vs 55 carbons for P-CTX-1), one extra ring, and a hemiketal in ring N but no spiroketal as found in P-CTX. C-CTX-1 possesses a primary hydroxyl which may allow selective derivatization. A minor analogue, C-CTX-2, was also isolated from fish and assigned the structure 56 epi-C-CTX-1 (2), since it slowly rearranged to C-CTX-1 in solution. Given the structural similarities between Caribbean and Pacific ciguatoxins, we propose that C-CTX-1 and C-CTX-2 arise from a Caribbean strain of the benthic dinoflagellate, Gambierdiscus toxicus.

Item Type:Article
Subjects:Veterinary medicine > Veterinary toxicology
Deposited On:22 Mar 2022 04:56
Last Modified:22 Mar 2022 04:56

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