From December 1992 to March 1993 in New Zealand, it had been first noted that several cases of intoxication following ingestion of bivalves contaminated with toxins occurred. In the course of our study on this event, we had isolated a new brevetoxin derivative conjugated with taurine, named brevetoxin B1 together with Pbtx-3 from cockle, Austrovenus stutchburyi, and Pbtx-2 and 3 from oyster, Crassostrae gigas, collected at the off coast of north New Zealand. (1-3) From these results, it is clear that neurotoxic shellfish poisons (NSPs), brevetoxins were responsible for this food poisoning. New Zealand oyster accumulates brevetoxins produced by dinoflagellate, Gymnodinium breve, in the body. However, it is suggested that cockle metabolites brevetoxin B to brevetoxin B1 before storing in the body, whereas stores Pbtx-3 directly. As there are new NSPs, differing from known brevetoxins including brevetoxin B1, in cockle, we have been continuing an isolation study on these new toxins. We have isolated three new NSPs together with brevetoxin B1 and Pbtx-3 from 80% methanol extract of cockle, using chromatographies on columns of SiO2 , ODS and Sephadex LH-20, following by reverse-phase HPLC, successively. Their structural determinations are on going.

1) H. Ishida et al., Tetrahedron Letters, 36, 725-728 (1995): 2) H. Ishida et al., Toxicon, 34, 1050-1053 (1996): 3) H. Ishida and K. Tsuji, Mycotoxins, 48, 29-31 (1999).