Oxidative Stress and Antioxidant Defense

Abstract

Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism and environmental factors, such as air pollutants or cigarette smoke. ROS are highly reactive molecules and can damage cell structures such as carbohydrates, nucleic acids, lipids, and proteins and alter their functions. The shift in the balance between oxidants and antioxidants in favor of oxidants is termed “oxidative stress.” Regulation of reducing and oxidizing (redox) state is critical for cell viability, activation, proliferation, and organ function. Aerobic organisms have integrated antioxidant systems, which include enzymatic and nonenzymatic antioxidants that are usually effective in blocking harmful effects of ROS. However, in pathological conditions, the antioxidant systems can be overwhelmed. Oxidative stress contributes to many pathological conditions and diseases, including cancer, neurological disorders, atherosclerosis, hypertension, ischemia/perfusion, diabetes, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. In this review, we summarize the cellular oxidant and antioxidant systems and discuss the cellular effects and mechanisms of the oxidative stress.

Protictive effects of green tea and garlic on the morphological and oxidative stress changes of hippocampus in aged male and female albino rats

“…In fact lipid peroxidation products have been used as indirect biomarkers of oxidative stress with aging [30]. According to [31], there is a great deal of interest in lipid peroxidation in terms of evaluating its importance as a primary mechanism of tissue injury and deterioration of a wide variety of cellular enzymes resulting in neurodegenerative process.…”

Pimpinella alpina Molk Administration is Capable of Increasing Antioxidant and Decreasing Prooxidant Level following UVB Irradiation

“…Numerous studies have reported that when, either depletion of antioxidants or accumulation of ROS (pro-oxidant and antioxidant imbalance) occur, cells attempt to counteract the pro-oxidant effect and restore the red-ox balance by activation or silencing of genes encoding defensive enzymes, transcription factors, and structural proteins 14,36 .…”

“…Similarly, increase in SOD is invariably followed by an increase in CAT, since SOD is primary enzyme account for dismutation of superoxide to H 2 O 2 . Subsequently, H 2 O 2 is reduced by CAT to oxygen and water 14 . In contrary, the increase in MDA and 8OHd Gconcentration always followed by the decrease in the activity of SOD and CAT or vice versa.…”

“…Hydroxyl radical has wide capacity to react with protein, nucleic acid, Polyunsaturated Fatty Acid (PUFA), and other molecules. Consequently, OH • is able to cause the tremendous alteration in cellular structures and damages 14 . On the other hand, O 2 -, 1 O 2 are able to liberate Fe 2+ from ferritin, lactoferin, and transferrin, subsequently induced Fenton reaction to form OH • which in turn induces further cellular damages 14 .…”

“…Consequently, OH • is able to cause the tremendous alteration in cellular structures and damages 14 . On the other hand, O 2 -, 1 O 2 are able to liberate Fe 2+ from ferritin, lactoferin, and transferrin, subsequently induced Fenton reaction to form OH • which in turn induces further cellular damages 14 . UVB irradiation on cells generates Malondihaldehide (MDA), resulting from reaction the between OH • and PUFA particularly arachidonic acid of cellular membrane.…”