[Oxidative stress and possibilities of its correction by melatonin]

Oxidative stress plays an important role in pathogensis of many metabolic disorders; therefore, effective antioxidant therapy should be an essential component of their treatment. Meanwhile, the meta-analysis of 68 randomized trials do not confirm this inference. The reason is peroxynitrite rather than oxygen (as previously believed) plays the key part in the damage of cell structure. Peroxynitrite is generated in the interaction between nitric oxide and superoxide anion radical leading to lipid peroxidation, protein oxidation, and DNA damage. This mechanism involves activation of several transcription factors responsible for cytokine-induced chronic inflammation. Classical antioxidants do not neutralize peroxinitrite effects. Melatonin is a multifunctional indolamine that has marked beneficial effect on peroxinitrite-induced cellular toxicity confirmed in numerous experimental and clinical studies. It may be used alone or in combination with other therapeutic agents to inhibit nitrooxidative stress.