[Fractionation of ciguatoxic lipid extracts in alkaline medium].

A modification of the extraction procedure for obtaining ciguatoxic substances from the tissues of various poisonous reef fish has been developed. Rapid alkali treatment of the residue obtained at an early stage is efficient in separating the ciguatoxic fraction from toxic impurities which interfere with pharmacological tests. It is thus possibles to carry out a more precise dosage of the material separated in this way. Alkali treatment does not affect either the physiological activity in cats and mice of the ciguatoxic substances nor their behaviour in a preparative thin layer chromatography in a benzene-butanol system.