Wine: No Wonder I Get So Sleepy

Melatonin, the neurohormone derived from tryptophan, was once thought to be produced only by vertebrate animals. It has been discovered that melatonin is produced by plants as well. Recently a study by Marcello Iriti, Mara Rossoni and Franco Faoro was published in the Journal of the Science of Food and Agriculture reporting that several grape varieties have significant levels of melatonin in their skins. Being the wino that I am, I was immediately drawn to this article as I'm always looking for information about wine and health. Interestingly, the rate of biosynthesis of melatonin in plants follows daily rhythmic fluctuations as it does in animals. The Italian researchers analyzed extracts from grape skins using HPLC and identified significant quantities of it. They examined nine different grape varieties, Barbera, Croatina, Cabernet Sauvignon, Cabernet Franc, Marzemino, Nebbiolo, Sangiovese, and Merlot. Lowest levels (0.005 ng per gram of skin) were found in Cabernet Franc while highest levels (0.965 ng per gram of skin) were detected in Nebbiolo. Interestingly, the levels in Merlot nearly tripled from 0.264 ng/g to 0.726 ng/g if the grape vines were treated with the plant defense activator, benzothiadiazole. One of the main applications of melatonin is in resetting our biological clocks when we travel across time zones. So, heading overseas? Take a bottle of wine with you! Oh, wait! Liquids are not allowed on planes anymore.