Ciguatoxins and Maitotoxins in Extracts of Sixteen Gambierdiscus Isolates and One Fukuyoa Isolate from the South Pacific and Their Toxicity to Mice by Intraperitoneal and Oral Administration

Abstract

Ciguatoxins (CTXs), and possibly maitotoxins (MTXs), are responsible for Ciguatera Fish Poisoning, an important health problem for consumers of reef fish (such as inhabitants of islands in the South Pacific Ocean). The habitational range of the <i>Gambierdiscus</i> species is expanding, and new species are being discovered. In order to provide information on the potential health risk of the <i>Gambierdiscus</i> species, and one <i>Fukuyoa</i> species (found in the Cook Islands, the Kermadec Islands, mainland New Zealand, and New South Wales, Australia), 17 microalgae isolates were collected from these areas. Unialgal cultures were grown and extracts of the culture isolates were analysed for CTXs and MTXs by liquid chromatography tandem mass spectrometry (LC-MS/MS), and their toxicity to mice was determined by intraperitoneal and oral administration. An isolate of <i>G. carpenteri</i> contained neither CTXs nor MTXs, while 15 other isolates (including <i>G. australes, G. cheloniae</i>, <i>G. pacificus</i>, <i>G.</i><i>honu</i>, and <i>F. paulensis</i>) contained only MTX-1 and/or MTX-3. An isolate of <i>G. polynesiensis</i> contained both CTXs and MTX-3. All the extracts were toxic to mice by intraperitoneal injection, but those containing only MTX-1 and/or -3 were much less toxic by oral administration. The extract of <i>G. polynesiensis</i> was highly toxic by both routes of administration.