The chemistry and biological function of natural marine toxins.

Studies on ciguatera fish poisoning led to clarification of the absolute stereochemistry of ciguatoxin, gambierol, gambieric acids, and maitotoxin. Anisotropic NMR reagents and fluorometric chiral HPLC reagents were effectively used together with synthesis of partial structures. Structures of 16 ciguatoxin congeners were successfully elucidated by FAB/MS/MS using samples of 5 microg or less. Stereochemical assignments were also achieved on dinophysistoxin-1, pectenotoxins, yessotoxins, polycavernoside-A, azaspiracid, and prymnesins. The toxins possessed poly-cyclic-ether structures and originated from unicellular algae. Biological functions are briefly described.