摘要: Living with oxygen is basically unsafe, but vital. During evolution, originally a waste product of the metabolism in primitive unicellular organisms became normal higher animal species involving humans. Even when oxidative reactions are toxic, and destructive, they tolerated by all to some extent. The fact has opened discussion about efficiency antioxidant mechanisms. classical enzyme defence alone does not explain high tolerance organism for oxygen. Moreover, mechanisms hundred percent effective preventing oxidation what allows damage continue.