MELATONIN IN THE PLANT KINGDOM: ONE MOLECULE, MULTIPLE ROLES

FEDERICO J. V. GOMEZ; ISMAEL GATICA HERNANDEZ; SOLEDAD CERUTTI; MARIA FERNANDA SILVA

Tenerife

Simposio; ITP 2013, 20th International Symposium on Electro - and Liquid Phase separation Techniques; 2013

Despite recent advances in the field of research on plant metabolism, in the metabololomic era only a few phytochemicals have been studied among the hundreds or thousands of secondary metabolites produced by plants. Many of these phytochemicals are reported to act synergistically, which may explain why some food items or diets may show cancer preventive effects that cannot be explained based on individual bioactive ingredients. Melatonin (N-acetyl-5-methoxytryptamine), the hormone of darkness, was first reported in food plants and medicinal herbs about two decades ago, and, more recently, it has been proposed as a healthy component of the traditional Mediterranean diet. Melatonin ubiquitous occurrence in plants has been demonstrated since then. Because of its structural similarity with the plant growth hormones of the auxin family, a hormone-like role has been attributed to melatonin in some plant species, as well as an action in delaying flowering, preventing chlorophyll degradation, protecting against oxidative damage, abiotic stresses, pathogens and environmental pollutants. In our lab, we have developed reliable analytical methodologies based on UPLC-MS/MS and CE for the determination of melatonin, its isomers and precursors in different plant tissues and /food samples. Thus, we were able to provide useful tools and knowledge to deduce physiological role of melatonin in plants. Biological function of melatonin in plants is beginning to be elucidated. We found that melatonin may protect lipids stored in seeds against peroxidation suffered during different stresses, thus increasing seeds viability and vigor. Our results support an antioxidant role for melatonin and show it naturally fluctuates in grapes during the day, indicating its function would be more important during the night and early in the morning. Surprisingly, melatonin was detected in grape extract while its isomers were found in musts and finished wines. Also, we demonstrated that yeasts play a decisive role in the production of melatonin and its isomers during wine production.