Fugu poisoning

Synonyms TTX Tarichatoxin Tetrodontoxin Fugu poison Maculotoxin (MTX) Spheroidine Chemical Formula CuFIiyNsOg... 

The Association of Puffer Fish Processing in Ishikawa Prefecture strictly requires that a Fugu poison test be conducted per production lot, and a certificate proving that a product passed this test is attached to every product distributed in the market. 

Yokoo [17] andTachikawa and Sakai [18] have provided reviews on the extraction and separation of Fugu poison.The latter review also summarizes the studies of the structure of TTX and related alkaloids, and their... 

Food poisonings also occur endemically, and concern food that is produced and consumed locally, e.g., Japanese fish fugu, or particular mushroom species. 

Many fish species, over 700 species worldwide, are either directly toxic or upon ingestion are poisonous to humans. A classic example is the toxin produced by the puffer fishes (Sphaeroides spp.) called tetrodotoxin (TTX). Tetrodotoxin is concentrated in the gonads, liver, intestine, and skin, and poisonings occurs most frequently in Japan and other Asian countries where the flesh, considered a delicacy, is eaten as fugu. Death occurs within 5 to 30 minutes and the fatality rate is about 60%. TTX is an inhibitor of the voltage-sensitive Na channel (like saxitoxin) it may also be found in some salamanders and may be bacterial in origin. 

The poisonous properties of the puffer fish have been known for centuries, and were described as early as ad 220 in China. A Chinese treatise written in ad 600 by Chaun Yanfang (Studies on the Origin of Diseases) described the liver, ovaries, and roe as the most poisonous. Despite the risks, puffer fish is stiU eaten as a delicacy in Japan, where it is known as fugu. Fish that contain the toxin are also accidentally eaten sometimes. Consequently poisoning cases do occur. Between 1974 and 1983 there were 646 cases and 179 fatalities. It has been estimated that as many as 200 cases a year may occur, with a mortality rate of up to 50 per cent. A trained chef should know which parts of the fish to avoid. 

Fortunately the synthesis of complex molecules is likely to involve the epoxidation of more rather than less crowded allylic alcohols. An outstanding recent example is Isobe s synthesis27 of 11-deoxytetrodotoxin 146, one of the metabolites of the notoriously poisonous Japanese fugu (puffer fish). Epoxidation of the allylic alcohol 144 gave an almost quantitative yield of one regio- and stereo-isomer of the epoxide 145. The mCPBA reagent was buffered with phosphate but that explains only the survival of the acetal the lack of epoxidation at the other alkene is remarkable as it has an allylic relationship with the rather acidic NH group. 

Scheme 15. Structure of tetrodotoxin, the cause of human poisonings ftom ingestion of tetrodetoxic fishes "Fugu".

Tetradotoxin is a potent neurotoxin isoiated from the ovaries and liver of many species of Tetradodontidae, especiaiiy the Japanese fugu (or puffer fish). Saxitoxin is a mussel or clam poison produced by certain marine dinoflagellates, Gonyaulax catenella or G. tamarensis, the consumption of which cause the mussels or clams to become poisonous. These poisonous shellfish were connected to a toxic red tide environmental condition on the coastal region of California in early 1970. Batrachotoxin is a cardiotoxic and neurotoxic steroid isolated originally from the poison dart frog, Phyllobates terribilis. It is a lipid soluble neurotoxin that is at least 10-fold more toxic than tetradotoxin. 

Cases occur during all months of the year. It is not known whether the proportion of tetrodotoxic fish has increased. Simple incidence data would not necessarily answer this question since public health measures such as education and regulation of fugu chefs in Japan may effect incidence estimates regardless of changes in the proportion of animals containing toxin. In addition, it is possible that improved medical care has lowered the number of lethal cases. The retrospective analysis of 42 outbreaks of tetrodotoxin-associated paralytic snail poisoning in Asia found no temporal variation [140],... 

Nukazuke of the ovaries of pufferfish (Fugu no mako zuke) is made in limited regions in Ishikawa Prefecture. The ovaries, which contain a deadly poison, are salted for at least lyear and soaked in rice bran for 2 years (Figure 16.5). Although researchers... 

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