3. Antioxidant protection systems

The process of oxidative modification of proteins, carbohydrates, DNA, and lipids is a universal mechanism of damage to the cell, especially at the membrane level. On the other hand, the numerous roles of free radicals in physiological processes make their creation a mandatory precondition of life, which is why a protective system has been established during evolutionary development. The basic role of this protection system is to reduce the amount and uncontrolled creation of free radicals and their precursors in the cell.

From a functional point of view, the antioxidant protection of the organism includes three levels of action:

	- a. Enzymatic (superoxide-dismutase, catalase, xanthine oxidase, peroxidase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase). These enzymes make the so-called primary line of antioxidant protection.
	- b.Nonenzymatic or the so-called secondary line of defense.
