eChapter Name: Medicinal Mushrooms Occurring in South India : An Untapped Novel Source of Antioxidants for Therapeutic Use
9789390512263
eBook Name: EXPERIMENTAL PHYTOCHEMICAL TECHNIQUES
by T.A. Ajith, K.K. Janardhanan
1. Introduction
During the last decade, considerable attention has been focused on the involvement of oxygen free radical (OFR) in various diseases. Molecular oxygen, while providing an efficient energy from ingested food, results in free radical and peroxide by-products, which have high intrinsic toxicity. Numerous physiological processes in living organisms occasionally produce free radicals, reactive nitrogen species (RNS) and reactive oxygen species (ROS) as by-products. Their broad ranges of effects in biological systems have drawn the attention of many experimental works. ROS have been implicated in the pathophysiology of several clinical disorders, including ischemia, reperfusion injury, myocardial infarction, rheumatoid arthritis, neurodegenerative, atherosclerosis, acute hypertension, hemorrhagic shock and diabetes mellitus (Hemnani and Parihar, 1998).
Oxidative stress occurs in a cell or tissue when the concentration of reactive oxygen species (ROS) generated exceeds the antioxidant capability of the cell (Simic and Jovanovic, 1986). Although humans and other organisms possess antioxidant defense and repair systems to protect against oxidative damage, these systems are insufficient under certain conditions to prevent the damage totally (Chang and Miles, 1982). Hence, the oxygen free radicals mediated damage to protein, DNA and other biomolecules accumulates during the lifetime of organisms. Many synthetic antioxidant components exhibited toxic or mutagenic effects that have directed the attention to the naturally occurring antioxidants in recent years. A multitude of natural antioxidants have already been isolated from different plant materials such as oilseeds, cereal crops, vegetables, fruits, leaves, roots, spices and herbs (Ramarathnam et al., 1995).