Wiktionary
n. (context biochemistry English) Any of several organic compounds with a complex polycyclic structure, that is responsible for the toxicity of some mussels (''Mytilus edulis'')
Wikipedia
Azaspiracids (AZA) are a group of polycyclic ether marine algal toxins produced by the small dinoflagellate Azadinium spinosum that can accumulate in humans causing illnesses.
Azaspiracid was first identified in the 1990s following an outbreak of human illness in the Netherlands that was associated with ingestion of contaminated shellfish originating from Killary Harbour, Ireland. To date, over 20 AZA analogues have been identified in phytoplankton and shellfish. Over the last 15 years, AZAs have been reported in shellfish from many coastal regions of western Europe, Northern Africa, South America, and North America. In addition, AZAs have been found in Japanese sponges and Scandinavian crabs. Not surprisingly, the global distribution of AZAs appears to correspond to the apparent wide spread occurrence of Azadinium. Empircal evidence is now available that unambiguously demonstrates the accumulation of AZAs in shellfish via direct feeding on AZA-producing A. spinosum.