Background: Melatonin is a natural body product that has shown potent antioxidant property
against various toxic agents. For more than two decades, the abilities of melatonin as a potent radioprotector
against toxic effects of ionizing radiation (IR) have been proved. However, in the recent
years, several studies have been conducted to illustrate how melatonin protects normal cells against
IR. Studies proposed that melatonin is able to directly neutralize free radicals produced by IR, leading
to the production of some low toxic products.
Discussion: Moreover, melatonin affects several signaling pathways, such as inflammatory responses,
antioxidant defense, DNA repair response enzymes, pro-oxidant enzymes etc. Animal studies have
confirmed that melatonin is able to alleviate radiation-induced cell death via inhibiting pro-apoptosis
and upregulation of anti-apoptosis genes. These properties are very interesting for clinical radiotherapy
applications, as well as mitigation of radiation injury in a possible radiation disaster. An interesting
property of melatonin is mitochondrial ROS targeting that has been proposed as a strategy for mitigating
effects in radiosensitive organs, such as bone marrow, gastrointestinal system and lungs. However,
there is a need to prove the mitigatory effects of melatonin in experimental studies.
Conclusion: In this review, we aim to clarify the molecular mechanisms of radioprotective effects of
melatonin, as well as possible applications as a radiation countermeasure in accidental exposure or