ABSTRACT
Oxidative stress depicts the existence of products called free radicals and reactive oxygen species (ROS), which are formed under normal physiological conditions but become deleterious when not being eliminated by the endog- enous systems. In fact, oxidative stress results from an imbalance between the generation of ROS and endogenous antioxidant systems. ROS such as superoxide anions, hydroxyl radicals and hydrogen peroxides are cytotoxic and give rise to tissue injuries [18,41,47]. Excessive amount of ROS is harmful because they initiate bimolecular oxidation, which leads to cell death 148and creates oxidative stress. In addition, oxidative stress causes inadvertent enzyme activation and oxidative damage to cellular system [10,68].
