Reactive oxygen species and free radicals (ROS)

Cellular reactive oxygen species (ROS) and free radicals are highly reactive, oxygen-containing molecules, such as superoxide anions, hydroxyl radicals, and hydrogen peroxide, generated primarily as byproducts of mitochondrial respiration and by specialized enzymes like NADPH oxidases (Source: NIH/National Cancer Institute). In physiological conditions, they function as essential secondary messengers in signal transduction pathways regulating cell growth, differentiation, and immune responses (Source: Nature Reviews Molecular Cell Biology). However, an overproduction or impaired clearance of these species leads to oxidative stress, which causes oxidative damage to lipids, proteins, and nucleic acids (Source: StatPearls). This damage is a hallmark of numerous pathologies, including cancer, cardiovascular diseases, and neurodegenerative disorders like Alzheimer's disease (Source: PubMed/PMC). Therapeutic strategies targeting ROS involve the use of antioxidant scavengers or inhibitors of ROS-generating enzymes to restore redox homeostasis. Despite their potential, clinical success has been limited by the dual nature of ROS, where excessive suppression can disrupt vital cellular processes, leading to reductive stress (Source: Journal of Biological Chemistry).

Other names

ROSFree radicalsOxidantsReactive oxygen intermediatesROIReactive nitrogen speciesRNSPro-oxidants

Direct chemical scavenging and neutralization of reactive species to prevent oxidative damage to cellular components (Source: StatPearls).