Melatonin and its metabolites: new findings regarding their production and their radical scavenging actions

Acta Biochim Pol. 2007;54(1):1-9. Epub 2007 Mar 9.


This review summarizes some of the recent findings concerning the long-held tenet that the enzyme, N-acetyltransferase, which is involved in the production of N-acetylserotonin, the immediate precursor of melatonin, may in fact not always control the quantity of melatonin generated. New evidence from several different laboratories indicates that hydroxyindole-O-methyltransferase, which O-methylates N-acetylserotonin to melatonin may be rate-limiting in some cases. Also, the review makes the point that melatonin's actions are uncommonly widespread in organs due to the fact that it works via membrane receptors, nuclear receptors/binding sites and receptor-independent mechanisms, i.e., the direct scavenging of free radicals. Finally, the review briefly summarizes the actions of melatonin and its metabolites in the detoxification of oxygen and nitrogen-based free radicals and related non-radical products. Via these multiple processes, melatonin is capable of influencing the metabolism of every cell in the organism.

Publication types

  • Review

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Free Radical Scavengers / metabolism*
  • Glutathione / metabolism
  • Humans
  • Hydrogen Peroxide / metabolism
  • Hydroxyl Radical / metabolism
  • Melatonin / biosynthesis
  • Melatonin / metabolism
  • Melatonin / physiology*


  • Antioxidants
  • Free Radical Scavengers
  • Hydroxyl Radical
  • Hydrogen Peroxide
  • Glutathione
  • Melatonin