Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2005 Jul;27(2):119-30.
doi: 10.1385/endo:27:2:119.

Antioxidative Protection by Melatonin: Multiplicity of Mechanisms From Radical Detoxification to Radical Avoidance

Affiliations
Review

Antioxidative Protection by Melatonin: Multiplicity of Mechanisms From Radical Detoxification to Radical Avoidance

Rüdiger Hardeland. Endocrine. .

Abstract

Melatonin has been shown to protect against oxidative stress in various, highly divergent experimental systems. There are many reasons for its remarkable protective potential. Signaling effects comprise the upregulation of antioxidant enzymes, such as superoxide dismutases, peroxidases, and enzymes of glutathione supply, down-regulation of prooxidant enzymes, such as nitric oxide synthases and lipoxygenases, and presumably also the control of quinone reductase 2. Other mechanisms are based on direct interactions with several reactive oxygen and nitrogen species. Among these reactions, the capacity of easily undergoing single-electron transfer reactions is of particular importance. Electron donation by melatonin is not only an aspect of direct radical scavenging, but additionally represents the basis for formation of the protective metabolites AFMK (N1-ace-tyl-N2-formyl-5-methoxykynuramine) and AMK (N1-acetyl-5-methoxykynuramine). Recent investigations on mitochondrial metabolism indicate that melatonin as well as AMK are capable of supporting the electron flux through the respiratory chain, of preventing the breakdown of the mitochondrial membrane potential, and of decreasing electron leakage, thereby reducing the formation of superoxide anions. Radical avoidance is a new line of investigation, which exceeds mitochondrial actions and also comprises antiexcitatory effects and contributions to the maintenance of internal circadian phase relationships.

Similar articles

See all similar articles

Cited by 128 articles

See all "Cited by" articles

References

    1. Adv Exp Med Biol. 1999;460:377-81 - PubMed
    1. J Photochem Photobiol B. 1998 Feb;42(2):125-32 - PubMed
    1. J Pineal Res. 2003 Nov;35(4):269-75 - PubMed
    1. J Pineal Res. 1995 Oct;19(3):111-5 - PubMed
    1. Biol Signals Recept. 2001 Nov-Dec;10(6):350-66 - PubMed
Feedback