MELATONIN IN EDIBLE PLANTS IDENTIFIED BY RADIOIMMUNOASSAY AND BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

Melatonin, the chief hormone of the pineal gland in vertebrates, is wi dely distributed in the animal kingdom. Among many functions, melatoni n synchronizes circadian and circannual rhythms, stimulates immune fun ction, may increase life span, inhibits growth of cancer cells in vitr o and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl r adicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin , in varying concentrations, is also found in a variety of plants. Mel atonin concentrations, measured in nine different plants by radioimmun oassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our fi ndings suggest that the consumption of plant materials that contain hi gh levels of melatonin could alter blood melatonin levels of the indol e as well as provide protection of macromolecules against oxidative da mage.