**3. Role of antioxidants**

*Antioxidants*

**Figure 4.**

*Reaction of hydroxyl radical with α-aminoacids [9].*

**28**

**Figure 5.**

*Reaction of hydroxyl radical with the basepair of DNA guanosine [8].*

Biological systems in oxygenated environments have developed defense mechanisms, both physiological and biochemical. Among them, at the physiological level, is a microvascular system with the function of maintaining the levels of O2 in the tissues, and at a biochemical level, the antioxidant defense can be enzymatic or nonenzymatic, as well as being a system for repairing molecules.
