Separation of pineal extracts on sephadex G-10 : III. Isolation and comparison of extracted and synthetic melatonin

Melatonin has been isolated from 300 gm of sheep pineal bodies by filtration of an aqueous extract on Sephadex G-10. Excitation and fluorescence maxima of the fractions of the column were measured and the fractions were tested for their blanching activity in tadpoles of Xenopus laevis. The microgram quantities of melatonin obtained after thin-layer chromatography were used for identification. The infrared spectrum of isolated melatonin in a KBr pellet is identical with that of synthetic melatonin treated in the same way as the isolated sample. It differs from the spectrum of synthetic melatonin, which has undergone no previous treatment. Heating of the KBr pellet of the isolated sample of melatonin for 5 min at 110°C, however, causes the spectrum to change into one which is nearly identical with that of untreated synthetic melatonin. The mass spectra of isolated and synthetic melatonin are identical. Proton magnetic resonance spectra of synthetic melatonin before and after thin-layer chromatography are presented