Melatonin as a radioprotective agent: A review

Vijayalaxmi, Russel J. Reiter, Dun Xian Tan, Terence S. Herman, Charles R. Thomas

Research output: Contribution to journalArticle

232 Scopus citations

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 (∼70%) result from its interaction with water molecules, which results in the production of highly reactive free radicals such as ·OH, ·H, and eaq - 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.

Original languageEnglish (US)
Pages (from-to)639-653
Number of pages15
JournalInternational Journal of Radiation Oncology Biology Physics
Volume59
Issue number3
DOIs
StatePublished - Jul 1 2004

Keywords

  • Antioxidant
  • Free radicals
  • Ionizing radiation
  • Melatonin
  • Radiation protection
  • Radiation terrorism

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Fingerprint Dive into the research topics of 'Melatonin as a radioprotective agent: A review'. Together they form a unique fingerprint.

  • Cite this