Abstract Oxidative stress occurs when there is a disturbance in the balance between production of reactive oxygen species and antioxidant defense system. Reactive oxygen species are radicals such as superoxide and hydroxyl while non radical reactive oxygen species are hydrogen peroxide, hypochlorite and singlet oxygen. Auto oxidation of glucose in diabetes, glycation of anti oxidative enzymes and leakage of reactive oxygen species from mitochondria cause increase in oxidative stress in diabetes. Impaired activities of antioxidant defense enzymes such as super oxide dismutase and catalase enhance oxidative cellular stress which can lead to vascular complications in diabetes. However, enzymatic antioxidants such as glutathione peroxide, glutathione reductase and catalase protect the body against the activities of free radicals by catalyzing components of superoxide to molecular oxygen and peroxide. Antioxidants such as Glutathione act as a scavenger as well as a substrate for glutathione peroxides. Non enzymatic antioxidants such as selenium, copper, zinc, ascorbic acid, carotenoids and vitamins also play a role in oxidative stress in diabetes by preventing lipid peroxidation, lowering insulin resistance and improving glucose uptake.
Keywords Oxidative Stress, Antioxidant, Diabetes, Free Radicals.