Phyconeurotoxins

Abstract

Phyconeurotoxins are marine compounds produced by 200 species of microalgae that target receptors in the nervous system. Some of the toxin groups are well recognized as potent neurotoxins, namely Brevetoxins, Cyclic Imines, Ciguatoxins, Domoic Acid, Saxitoxins, and Tetrodotoxins. Ciguatoxins are produced by microalgae but only reported in fish, and for this reason their toxicology and food safety poses a special difficulty. Tetrodotoxins are present in both fish and shellfish; they are produced by bacteria, but some microalgae have associated bacteria that produce the toxin. All other toxin groups are associated with shellfish toxicity. Okadaic acid analogs and Azaspiracids might be included in this group of neurotoxins, although their mode of toxicity is under scientific scrutiny, and in consequence they are not fully accepted neurotoxins. In general, phyconeurotoxins are very diverse in chemical structure and mechanism of action. They are privileged structures that interact with their receptors at very low concentrations. Only Saxitoxins and Domoic acid are clearly considered lethal toxins in mammals. It remains to be clarified the biological role of phycotoxins, as they are harmless to fish or feed-filtering molluscs.