Melatonin as a natural ally against oxidative stress: a physicochemical examination

Abstract

: Oxidative stress has been proven to be related to the onset of a large number of health disorders. This chemical stress is triggered by an excess of free radicals, which are generated in cells because of a wide variety of exogenous and endogenous processes. Therefore, finding strategies for efficiently detoxifying free radicals has become a subject of a great interest, from both an academic and practical points of view. Melatonin is a ubiquitous and versatile molecule that exhibits most of the desirable characteristics of a good antioxidant. The amount of data gathered so far regarding the protective action of melatonin against oxidative stress is overwhelming. However, rather little is known concerning the chemical mechanisms involved in this activity. This review summarizes the current progress in understanding the physicochemical insights related to the free radical–scavenging activity of melatonin. Thus far, there is a general agreement that electron transfer and hydrogen transfer are the main mechanisms involved in the reactions of melatonin with free radicals. However, the relative importance of other mechanisms is also analyzed. The chemical nature of the reacting free radical also has an influence on the relative importance of the different mechanisms of these reactions. Therefore, this point has also been discussed in detail in the current review. Based on the available data, it is concluded that melatonin efficiently protects against oxidative stress by a variety of mechanisms. Moreover, it is proposed that even though it has been referred to as the chemical expression of darkness, perhaps it could also be referred to as the chemical light of health.

Melatonin-Induced Oncostasis, Mechanisms and Clinical Relevance

“…Melatonin has a marked dose-dependent antioxidative effect, providing protection against damage from carcinogenic substances and acting as a free radical scavenger [138]. ROS generation is a major factor involved in carcinogenesis [139].…”

Role of Carnosine and Melatonin in Ameliorating Cardiotoxicity of Titanium Dioxide Nanoparticles in the Rats

“…Melatonin, a hormone secreted from the pineal body is involved in the light-dark cycle and is also involved in the regulation of the immune system. Melatonin may be involved in cancer prevention through a role in conservation DNA integrity (Galano 2011;. The current work aimed to detect the possible toxic effects of low dose (60 mg/kg) as well as high dose (1g/kg) 50 nm n-TiO 2 on cardiac tissues of rats.…”

“…Also, it can oppose the oxidative stress in mitochondrial and the cyanide induced-inhibition of ATP by increasing ATP synthesis. It is called as a suicidal antioxidant, as it is consumed during its action (Galano 2011;Athanassiou 2013). It is suggested that melatonin has a role in modulating several physiological processes, including the control of blood pressure, and tumor growth (Abdelkarem and Faddah 2013).…”

Melatonin reduces acute lung inflammation, edema, and hemorrhage in heatstroke rats

“…Melatonin, the main product of the pineal gland, is found in high concentrations in other body fluids and tissues [7,8] and has anti-oxidant and anti-inflammatory actions [9][10][11][12] . We have evaluated the prophylactic effect of melatonin in heatstroke rats and showed that the systemic delivery of melatonin immediately before the start of heat stress significantly prolongs the survival time of heatstroke rats [13] .…”