Last update:
01-Apr-2009

Several types of reactive species are generated in the body in the form of free radicals or non-radicals as a result of metabolic reactions. These species may be either oxygen derived or nitrogen derived and are called pro-oxidants. They attack macro-molecules, including protein, DNA and lipid etc., causing cellular/tissue damage. To counteract their effect, the body is endowed with another category of compounds called antioxidants. These antioxidants are either produced endogenously or come from exogenous sources, and they include enzymes such as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, minerals such as Se, Mn, Cu and Zn, and vitamins such as vitamin A, C and E, and other compounds with antioxidant activity such as glutathione. In a healthy body, the pro-oxidants and antioxidants maintain a ratio, and a shift in this ratio towards pro-oxidants gives rise to oxidative stress. This oxidative stress may be either mild or severe depending on the extent of the shift, and constitutes the cause of several diseases such as cardiovascular diseases, neurological diseases, malignancies, renal diseases, diabetes, inflammatory problems, skin diseases, aging, respiratory diseases, liver diseases and different types of viral infection. As more and more reports are published, a wealth of information is being produced about oxidative stress in relation to several other diseases. The pharmacological modulation of the oxidative stress response is a hot topic of current research.

Key words: Antioxidants, Oxidative stress, Oxygen free radicals, Pro-oxidants.