Some Pharmacological Properties of Palythoatoxin Isolated from the Zoanthid, Palythoa tuberculosa

Abstract

During the course of the survey of causes of ciguatera poisoning, a pharmacologically very active substance was obtained from the zoanthid (Coelenteratd), Palythoa tuberculosa Esper (Kimuraet al., 1972; Kimura and Hashimoto, 1973) found in the digestive tract of a filefish, Alutera scripta, one most widely re puted as ciguatoxic in the tropical and subtropical regions (Hashimoto et al. 1969). This substance has been found to be selectively distributed in female polyps of the zoanthid, especially concentrated in their matured stage (Kimura et al., 1972). The lethal dose of this substance has been estimated to be 0.6 µg/ kg in mice when intraperitoneally injected (Kimura and Hashimoto, 1973). This toxicity far exceeds that of tetrodotoxin or saxitoxin, and may even exceed that of batrachotoxin, the most potent of natural toxins of low molecular weight ever known (Daly et al., 1965). This substance, here designated as palythoatoxin, has been reported to be very similar, if not identical, to palytoxin previously isolated by Moore and Scheuer (1971) from closely related Palythoa species (P. vestitus and P. toxica) (Kimura and Hashimoto, 1973). The latter reportedly has an estimated molecular weight of about 3300, is not a polypeptide or a protein nor does it contain sugar, and has lethal doses of 0.4 µg/kg (i.p.) and 0.15 µg/kg O-v.) in mice (Moore and Scheuer, 1971; see also Sheikh, 1970).