Phytomelatonin: A Review

Abstract

Melatonin (N-acetyl‑5-methoxy tryptamine) is an indole hormone; for a long time, it was thought to occur only in animals and humans. Thirty years after its discovery, melatonin was also detected in plants. The ubiquitous presence and high concentrations of melatonin in higher plants, as opposed to animals, led to introduction of the term “phytomelatonin” in 2004. At present, phytomelatonin has been shown to induce antioxidant, antistress, and growth-promoting effects. At the same time, the contribution of melatonin to circadian rhythms and photoperiodic regulation, though well-studied in animals, is still questionable in plants. It is supposed that melatonin could be used in agricultural practice to enhance the stress-tolerance and productivity of plants. This review discusses the history of melatonin research in plants and recent advances in the understanding of its functions.