Oxidative stress reflects an imbalance between the appearance of reactive oxygen species and degradation in a biological system

Oxidative stress reflects an imbalance between the appearance of reactive oxygen species and degradation in a biological system (Cachofeiro et al., 2008). Oxidative stress leads to production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA base damage. Further, some reactive oxidative species act as cellular messengers in redox signaling. Oxidative stress is the known to play a crucial role in the the development of various diseases like cancer, Parkinson’s disease, Alzheimer’s disease, atherosclerosis, heart failure, myocardial infarction,infection, Chronic fatigue syndrome, hypertension, diabetes, depression, aging and in Acute Kidney Injury AKI (Cachofeiro et al., 2008; Kumar et al., 2015; Rahal et al., 2014). In normal conditions, there is a balance between the production of oxidizing species and antioxidant defences. But in pathological conditions there is depletion of antioxidant speices such as glutathione, SODs, which futher leads to cell death, like apoptosis, and necrosis. Oxidative stress has been implicated in various animal models of kidney injury caused due hypertension, obesity, diabetes, urinary obstruction, transplantation,ischaemia reperfusion injury,urolithiasis,infection, antibiotics, Immunosuppressants,Non-steroidal inflammatory drugs, radio-contrast agents, analgesics, antineoplasti agents,alcohol, smoking,environmental toxins and radiations (Ozbek, 2012).
In response to excess ROS production during respiration and metabolism, cellular system has evolved numerous antioxidant systems including free radical scavengers and enzymes (Fig. 1.4). The primarily and most important antioxidant enzymes is superoxide dismutase (SOD), which exists in three major cellular forms: copper zinc (CuZnSOD, SOD1), manganese (MnSOD, SOD2), and extracellular (SOD3). These enzymes are mainly responsible for the detoxification of superoxide radicals to hydrogen peroxide and water in different cellular compartments. Glutathione peroxidase (GPx) and catalase are other antioxidant enzymes that catalyze the conversion of hydrogen peroxide to water. Some of the other antioxidants also present within cells, such as glutathione and numerous vitamins. It has been found that antioxidants have proven to play a crucial role in the treatment of diabetic nephropathy in various studies both on animals and humans (Koya et al., 2003; Mshelia, 2004)