Melatonin as a mitochondria-targeted antioxidant: one of evolution’s best ideas

Russel J. Reiter, Sergio Rosales-Corral, Dun-xian Tan, Mei Jie Jou, Annia Galano, Bing Xu

Research output: Contribution to journalReview articlepeer-review

352 Scopus citations


Melatonin is an ancient antioxidant. After its initial development in bacteria, it has been retained throughout evolution such that it may be or may have been present in every species that have existed. Even though it has been maintained throughout evolution during the diversification of species, melatonin’s chemical structure has never changed; thus, the melatonin present in currently living humans is identical to that present in cyanobacteria that have existed on Earth for billions of years. Melatonin in the systemic circulation of mammals quickly disappears from the blood presumably due to its uptake by cells, particularly when they are under high oxidative stress conditions. The measurement of the subcellular distribution of melatonin has shown that the concentration of this indole in the mitochondria greatly exceeds that in the blood. Melatonin presumably enters mitochondria through oligopeptide transporters, PEPT1, and PEPT2. Thus, melatonin is specifically targeted to the mitochondria where it seems to function as an apex antioxidant. In addition to being taken up from the circulation, melatonin may be produced in the mitochondria as well. During evolution, mitochondria likely originated when melatonin-forming bacteria were engulfed as food by ancestral prokaryotes. Over time, engulfed bacteria evolved into mitochondria; this is known as the endosymbiotic theory of the origin of mitochondria. When they did so, the mitochondria retained the ability to synthesize melatonin. Thus, melatonin is not only taken up by mitochondria but these organelles, in addition to many other functions, also probably produce melatonin as well. Melatonin’s high concentrations and multiple actions as an antioxidant provide potent antioxidant protection to these organelles which are exposed to abundant free radicals.

Original languageEnglish (US)
Pages (from-to)3863-3881
Number of pages19
JournalCellular and Molecular Life Sciences
Issue number21
StatePublished - Nov 1 2017


  • Apoptosis
  • Cytochrome c
  • Free radical-related diseases
  • Inner mitochondrial membrane
  • Melatonin transporters
  • Mitochondrial transition pore
  • Reactive oxygen species
  • SIRT3

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Molecular Medicine
  • Molecular Biology
  • Cell Biology
  • Pharmacology


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