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Melatonin as a radioprotective agent: a review.
Int J Radiat Oncol Biol Phys. 2004 Jul 01; 59(3):639-53.IJ

Abstract

Melatonin (N-acetyl-5-methoxytryptamine), the chief secretory product of the pineal gland in the brain, is well known for its functional versatility. In hundreds of investigations, melatonin has been documented as a direct free radical scavenger and an indirect antioxidant, as well as an important immunomodulatory agent. The radical scavenging ability of melatonin is believed to work via electron donation to detoxify a variety of reactive oxygen and nitrogen species, including the highly toxic hydroxyl radical. It has long been recognized that the damaging effects of ionizing radiation are brought about by both direct and indirect mechanisms. The direct action produces disruption of sensitive molecules in the cells, whereas the indirect effects (approximately 70%) result from its interaction with water molecules, which results in the production of highly reactive free radicals such as *OH, *H, and e(aq)- and their subsequent action on subcellular structures. The hydroxyl radical scavenging ability of melatonin was used as a rationale to determine its radioprotective efficiency. Indeed, the results from many in vitro and in vivo investigations have confirmed that melatonin protects mammalian cells from the toxic effects of ionizing radiation. Furthermore, several clinical reports indicate that melatonin administration, either alone or in combination with traditional radiotherapy, results in a favorable efficacy:toxicity ratio during the treatment of human cancers. This article reviews the literature from laboratory investigations that document the ability of melatonin to scavenge a variety of free radicals (including the hydroxyl radical induced by ionizing radiation) and summarizes the evidence that should be used to design larger translational research-based clinical trials using melatonin as a radioprotector and also in cancer radiotherapy. The potential use of melatonin for protecting individuals from radiation terrorism is also considered.

Authors+Show Affiliations

Vijayalaxmi
Department of Radiation Oncology, The University of Texas Health Science Center, San Antonio, 78229, USA. vijay@uthscsa.edu
Reiter RJ
No affiliation info available
Tan DX
No affiliation info available
Herman TS
No affiliation info available
Thomas CR
No affiliation info available

MeSH

AnimalsAntioxidantsDNADNA DamageFree Radical ScavengersHumansMelatoninMiceRadiation InjuriesRadiation-Protective AgentsTerrorism

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

15183467

Citation

Vijayalaxmi, , et al. "Melatonin as a Radioprotective Agent: a Review." International Journal of Radiation Oncology, Biology, Physics, vol. 59, no. 3, 2004, pp. 639-53.
Vijayalaxmi , Reiter RJ, Tan DX, et al. Melatonin as a radioprotective agent: a review. Int J Radiat Oncol Biol Phys. 2004;59(3):639-53.
Vijayalaxmi, ., Reiter, R. J., Tan, D. X., Herman, T. S., & Thomas, C. R. (2004). Melatonin as a radioprotective agent: a review. International Journal of Radiation Oncology, Biology, Physics, 59(3), 639-53.
Vijayalaxmi , et al. Melatonin as a Radioprotective Agent: a Review. Int J Radiat Oncol Biol Phys. 2004 Jul 1;59(3):639-53. PubMed PMID: 15183467.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Melatonin as a radioprotective agent: a review. AU - Vijayalaxmi,, AU - Reiter,Russel J, AU - Tan,Dun-Xian, AU - Herman,Terence S, AU - Thomas,Charles R,Jr PY - 2003/08/07/received PY - 2004/01/14/revised PY - 2004/02/06/accepted PY - 2004/6/9/pubmed PY - 2004/7/15/medline PY - 2004/6/9/entrez SP - 639 EP - 53 JF - International journal of radiation oncology, biology, physics JO - Int J Radiat Oncol Biol Phys VL - 59 IS - 3 N2 - Melatonin (N-acetyl-5-methoxytryptamine), the chief secretory product of the pineal gland in the brain, is well known for its functional versatility. In hundreds of investigations, melatonin has been documented as a direct free radical scavenger and an indirect antioxidant, as well as an important immunomodulatory agent. The radical scavenging ability of melatonin is believed to work via electron donation to detoxify a variety of reactive oxygen and nitrogen species, including the highly toxic hydroxyl radical. It has long been recognized that the damaging effects of ionizing radiation are brought about by both direct and indirect mechanisms. The direct action produces disruption of sensitive molecules in the cells, whereas the indirect effects (approximately 70%) result from its interaction with water molecules, which results in the production of highly reactive free radicals such as *OH, *H, and e(aq)- and their subsequent action on subcellular structures. The hydroxyl radical scavenging ability of melatonin was used as a rationale to determine its radioprotective efficiency. Indeed, the results from many in vitro and in vivo investigations have confirmed that melatonin protects mammalian cells from the toxic effects of ionizing radiation. Furthermore, several clinical reports indicate that melatonin administration, either alone or in combination with traditional radiotherapy, results in a favorable efficacy:toxicity ratio during the treatment of human cancers. This article reviews the literature from laboratory investigations that document the ability of melatonin to scavenge a variety of free radicals (including the hydroxyl radical induced by ionizing radiation) and summarizes the evidence that should be used to design larger translational research-based clinical trials using melatonin as a radioprotector and also in cancer radiotherapy. The potential use of melatonin for protecting individuals from radiation terrorism is also considered. SN - 0360-3016 UR - https://www.unboundmedicine.com/medline/citation/15183467/Melatonin_as_a_radioprotective_agent:_a_review_ DB - PRIME DP - Unbound Medicine ER -