Ciguatoxin

Ciguatoxins (CTX ) are a group of about twenty -built complex, structurally closely related, highly neurotoxic polycyclic polyethers. They are metabolites of a marine dinoflagellate and contributor of Ciguatera food poisoning. The ciguatoxin is synonymous with ciguatoxin CTX1B.

History

The structure of the ciguatoxin CTX1B was elucidated in 1989. To this end, from 4150 kg giant moray ( Gymnothorax javanicus) were only 0.36 mg of the toxin isolated. This small amount was enough yet to elucidate the very complex structure of the polyether.

A first total synthesis of ciguatoxin ( CTX3C ), whose complex structure contains 13 rings of cyclic ethers with 30 stereocenters, was published in 2001.

Occurrence

You are metabolic products of the widespread in tropical and subtropical regions of the Pacific Ocean, the Indian Ocean and the Caribbean dinoflagellate Gambierdiscus toxicus. In the marine food chains there is accumulation of these toxins, as a consequence of man eating fish may contain effective doses of the ciguatoxins.

Interestingly, we find the actual ciguatera CTX1B not as a direct metabolite of dinoflagellates, but occurs only at higher trophic levels in appearance. Also included representatives of these levels tend to have more higher hydroxylated derivatives, while isolate from cultures of Gambierdiscus toxicus rather nonpolar representative (eg CTX3C ). This fact is due to the metabolism of the animal organism in ciguatoxins. As the toxicity with increasing hydrophilic character of the compound greatly increases their Wirkungspotenzierung occurs in the food chain in addition to the accumulation of toxins. So CTX1B is about ten times more toxic than the poorer three hydroxyl groups CTX4B.

Properties

Ciguatoxins are colorless oils. They are chemically relatively stable. For example, they are not destroyed by cooking the food preparation.

Biological Significance

The enjoyment of ciguatoxin - contaminated food fish caused a serious, rarely fatal extending food poisoning, the so-called ciguatera. Ciguatoxins bind to voltage-gated sodium channels and cause their permanent activation. Typical signs of poisoning include numbness in the extremities, paresthesias, disturbances of hot -cold feeling and vomiting. The symptoms can last for days, but often even weeks to years. The poisoning can only be treated symptomatically, as no antidote is available.

The LD50 is 6.24 g / kg intraperitoneally for mice receiving for CTX1B 1.64 ug / kg and for CTX3C.

Representative

  • CTX1B
  • Ciguatoxin
  • CTX2
  • 52 -epi- ciguatoxin 3
  • CTX3
  • CTX3C
  • 51 -hydroxy- CTX3C
  • CTX4A
  • CTX4B
  • Scaritoxin
  • Gambiertoxin 4b
  • 52 -epi- ciguatoxin 4A
  • CTX4C
Neurotoxin Sea Voltage-gated ion channel Symptomatic treatment Intraperitoneal injection CAS registry number Diastereomer
190267
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