Toxins Found in Ciguatqxic Fishes in the Ryukyu Islands

TOXINS FOUND IN CIGUATOXIC FISHES IN THE RYUKYU ISLANDS by Yoshiro HASHIMOTO * Evidence for multiplicity of toxin involved in ciguatera has been increasingly accumulated. At least four different toxins have been demonstrated in ciguatoxic fishes in the Ryukyu Islands. The fat-soluble toxin probably identical with ciguatoxin was found in the muscle of Lut/janus bohar and L. monostiqma. This toxin may be a principal one in ciguatera, as Dr Banner suggested. A water-soluble toxin causing transient vomiting in cats was found and designated as ciguaterin. It was confirmed to distribute widely in the liver and occasionally in the muscle of representative ciguatoxic fishes. This toxin, however, may be a leas important factor than ciguatoxin for development of ciguatera. The skin of a sea bass (Poqonoperca punctata) was found to contain a toxin inducing in cats ciguatera-like syndromes when force-fed or injected. Besides, it revealed both ichtyotoxic and hemolytic activities and a close similarity to the ichtyotoxin found in soapfish rather than pahutoxin in boxfish. Finally, a water-soluble substance toxic to mice was detected in the viscera and digestive tract contents of a filefish (aluteres scriptus). From the chemical properties it is supposed to be a new marine toxin. The toxin in the viscera was indistinguishable in chemical and pharmacological properties from that in the ingested materials which were mainly consisted of broken reef corals tentatively identified as Goniopora sp. This may strongly suggest the presence of toxic reef corals which serve as a primary source of toxin in a filefish and presumably many other coral feeders. Original Text : English •Laboratory of iiarine Biochemisty, Faculty of Agriculture, the University of Tokyo.