Table 1.

Main oxidants and anti-oxidants.

Oxidants	Anti-oxidants
Free radicals Hydroxyl radical, superoxide peroxyl, lipid peroxyl	Enzymes Superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase
Reactive Oxygen Species (ROS) Peroxide, singlet oxygen, hypochlorous acid and lipid peroxides	Vitamins A, C, E
Reactive Nitrogen Species (RNS) Hydrogen nitric oxide, nitrogen dioxide, nitrous acid, peroxynitrite, dinitrogen trioxide	Minerals Se, Mn, Cu and Zn
	Other substances glutathione, melatonin, thiols, coenzyme Q, acetylcysteine, carotenoids and flavonoids

Table summarizes the most common oxidants and the main endogenous and exogenous antioxidants.