Oxidative Stress and Tissue Damage

When food is converted to energy using oxygen, many intermediate products harmful to the body are formed and are called reactive oxygen metabolites (free radicals). These molecules can damage basic cell components such as lipids, proteins and DNA. Antioxidant defence systems exist in aerobic organisms to control the formation of free radicals and to prevent the harmful effects of these molecules. However, in some cases, the available antioxidant defence system can’t completely inhibit the action of free radicals, and the condition is called as oxidative stress. Oxidative stress is a state of imbalance between, free radical production in the tissues and organs and the ability of the body to counteract their harmful effects through neutralization by antioxidants. Oxidative stress plays an important role in many disease states, when excess oxygen radicals are produced in cells, overwhelming the normal antioxidant capacity. Oxidative damage occurs to proteins, lipids, and DNA, when the concentration of reactive species is not controlled by counteracting antioxidants such as tocopherols, ascorbic acid, and glutathione or enzymes involved in oxygen radical scavenging such as catalase, peroxidase, and superoxide dismutase, leading to cytotoxicity, genotoxicity, and even carcinogenesis