Melatonin has been identified in many plants including feverfew (Tanacetum parthenium), St John's wort (Hypericum perforatum)., rice, corn, tomato and other edible fruits. The physiological roles of melatonin in plants involve regulation of their response to photoperiod, defense against harsh environments, and the function of an antioxidant. The latter may be the original function of melatonin in organisms with the others being added during evolution. Melatonin also regulates plant growth by its ability to slow root formation, while promoting above ground growth.
Melatonin has been reported in foodstuffs including cherries to about 0.17–13.46 ng/g, bananas and grapes, rice and cereals, herbs, olive oil,wine and beer.
When birds ingest melatonin-rich plant feed, such as rice, the melatonin binds to melatonin receptors in their brains.[17] When humans consume foods rich in melatonin such as banana, pineapple and orange the blood levels of melatonin significantly increase.
mel·a·to·nin
color-changing hormone: a hormone derived from serotonin and secreted by the pineal gland that produces changes in the skin color of vertebrates, reptiles, and amphibians and is important in regulating biorhythms
