Comprehending Human Disorders: Focus on Reactive Oxygen Species

Reactive Oxygen Species (ROS) are highly reactive oxygen moieties which result in the cellular state of oxidative stress, either due to their overproduction or by imbalance between cellular oxidants and antioxidant system. Mitochondria is the main source and site of ROS production inside a cell and account for both - electron transport chain (ETC) and non-ETC dependent sources. Interestingly, a threshold level of ROS is essential for cellular functioning, nevertheless, any unexpected increase in its level poses detrimental effects on the cells by oxidizing biomolecules such as proteins, lipids, nucleic acids etc. Although cellular machinery is well equipped with both enzymatic and non-enzymatic antioxidant defense systems, cellular injury and aging due to generation of ROS is inevitable in all living systems. Higher levels of ROS are thus been commonly associated with onset of several human diseases such as neurodegenerative disorders, cancer, infertility etc. Present review attempts to provide a brief account of ROS and their regulation in cellular systems along with their potential involvement in predisposition of some fatal human diseases.