Red Wines Contain Melatonin

Scientists in Italy say they have discovered that the grapes used to make some of the most popular red wines contain high levels of the sleep hormone melatonin. Melatonin is thought to be a powerful antioxidant and so could contribute to the antioxidant effects of wine along with resveratrol, proanthrocyanidins and anthrocyanins.

The discovery of melatonin in grape skin could explain why many drink wine in the evening to wind down. 'The melatonin content in wine could help regulate the circadian rhythm [sleep-wake patterns], just like the melatonin produced by the pineal gland in mammals,' says researcher Iriti Marcello at the University of Milan, the lead researcher.

Until recently, melatonin was thought to be exclusively produced by mammals but has recently been discovered in plants. It is thought to have antioxidant properties. Iriti's study discovered high levels of melatonin in Nebbiolo , Merlot, Cabernet Savignon, Sangiovese and Croatina grape varieties. 3 other varieties had lower levels: Croatina, Cabernet Franc and Barbera. The highest level was 0.965 ng/g found in Nebbiolo and the lowest level of 0.870 ng/g was found in Croatina wine. Iriti's team have also shown that melatonin content can be enhanced in grapes by treating vines with a plant defence activator Benzothiadiazole.

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