Free radicals are highly reactive substances with a structure characterised by at least one unpaired electron. They are used within the body for the physiological metabolism of cells, the synthesis of hormones and neurotransmitters and as a defence against pathogens. Increased production of radicals can, however, lead to radical-induced oxidation and, consequently, to oxidative stress. Cells are protected from oxidative stress by the antioxidant system, which has preventive and curative function. One of the mechanisms for protecting cells is the enzymatic antioxidant superoxide dismutase which removes the superoxide anion. The importance of the superoxide dismutase has led to the development of enzyme mimetics – antioxidants which mimic the activities of this enzyme.
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