A REVIEW ON REACTIVE OXYGEN AND NITROGEN SPECIES

Generally Reactive oxygen species (ROS) and Reactive nitrogen species (RNS) consist of free radicals and hasty species in these two groups and breakdown yield of lipids proteins, nucleic acids and carbohydrates. Free radicals (FR) contain one or more unpaired electrons and could be positively -.2 or negatively charged or neutral in nature. Superoxide anion (O ), free .- hydroxyl radical (OH ) and nitric oxide (NO·) are important free radicals in human body and produce numerous additional free radicals mostly from unsaturated fatty acids. Physiologically they can be defined as overactive disjointed atoms or molecules which are capable of upsetting and fragmenting other molecules. Free hydroxyl is the mainly reactive neutral -9 free radical with half life of about 10 second. It is capable of insulting fragmenting and mutating any cellular molecule -.2 with forceful passion. Superoxide anion (O ) in human body arises from metabolic reactions, irradiation and leakage from electron transport chain. Superoxide is often referred as primary ROS as most of other ROS and RNS arise from it and are therefore termed as secondary ROS and RNS. These free radicals are produced in cellular membrane mitochondria, nucleus, lysosomes, peroxisomes, endoplasmic reticulum and cytoplasm. Redox-sensitive proteins with important cellular functions are confined to signalling microdomains in cardiovascular cells and are not readily available for quantification. A popular approach is the measurement of stable by-products modified under conditions of oxidative strain that have entered the circulation. However, these may not accurately reflect redox stress at the cell/tissue height. Many of these modifications are “functionally silent”. Functional importance of the oxidative modifications enhances their validity as a proposed biological marker of cardiovascular disease, and is the strength of the redox cysteine modifications such as glutathionylation. We assess selected biomarkers of oxidative stress that show promise in cardiovascular medicine, as well as new methodologies for high-throughput measurement in research and clinical settings. Although associated with disease severity, supplementary studies are necessary to examine the usefulness of the most promise oxidative biomarkers to forecast prognosis or rejoinder to treatment.