Azaspiracid, diarrhetic shellfish poisoning caused

B. Diarrhetic shellfish poisoning causes nausea, vomiting, stomach cramps, and severe diarrhea. In animal studies, azaspiracid toxin caused damage to the liver, spleen, and small intestine. 

In 1995, a report of human illness with diarrhetic shellfish poisoning (DSP)-like symptoms in the Netherlands was eventually found to result from the consumption of poisoned mussels (Mytilus edulis) harvested from Killary Harbour, Ireland (McMahon 1996). Yasumoto, Satake, and co-workers eventually isolated and proposed a stracture for the causative agent of this condition azaspiracid-1 (la. Fig. 16.1). The unique polyether stracture of azaspiracid-1 (la) is characterized by several spiro-cyclic systems, including an azaspiro ring fused to a 2,9-dioxabicyclo[3.3.1]nonane system and a terminal carboxylic acid. In total, there are nine rings and twenty stereogenic centers within the structure proposed by Yasumoto and co-workers in 1998 (Satake 1998). This stracture was based primarily on NMR spectroscopic data and did not include absolute stereochemistry, nor did it specify relative stereochemistry between the ABCDE and FGHI domains. 

The clinical symptoms caused by azaspiracid poisoning in humans are similar to diarrhetic shellfish poisoning and to bacterial enterotoxin poisoning. Because of the similarity of the gastrointestinal symptoms induced by this new toxin and the well characterized DSP (diarrheic shellfish poisoning) toxins in humans, azaspiracids have been classified at times in the diarrheic toxin group. However, when the chemical stmcture of this new toxin was identified as a completely different molecule from DSP toxins, this toxic syndrome was named azaspiracid poisoning (AZP). 

B. Diarrhetic shellfish poisoning is caused by several identified toxins, all of which appear to be produced by marine dinoflagellates. Suspected toxins include okadaic acid, dinophysistoxins, and azaspiracid. 

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