Melatonin: Lowering the High Price of Free Radicals.

The endogenous antioxidative defense system reduces molecular toxicity of oxygen and nitrogen-based reactive species. Melatonin is an efficient direct and indirect antioxidant. It detoxifies the highly reactive hydroxyl radical and neutralizes other toxic species, including singlet oxygen, hydrogen peroxide, nitric oxide, and peroxynitrite anion, and stimulates several antioxidative enzymes.