Reactive oxygen species and endogenous antioxidant defense system (ROS/Antioxidant system)

The reactive oxygen species (ROS) and endogenous antioxidant defense system represent a complex network of molecules and enzymes that maintain cellular redox homeostasis (StatPearls, 2023). ROS, including superoxide anions, hydroxyl radicals, and hydrogen peroxide, are natural byproducts of oxygen metabolism and serve as critical signaling molecules at low concentrations (NIH, 2022). The endogenous antioxidant system, comprising enzymes like superoxide dismutase (SOD), catalase, and glutathione peroxidase, as well as non-enzymatic molecules like glutathione, neutralizes excess ROS to prevent oxidative damage to lipids, proteins, and DNA (PubMed, 2021). An imbalance between ROS production and antioxidant capacity leads to oxidative stress, a key driver in the pathogenesis of cancer, neurodegeneration, and cardiovascular diseases (Nature Reviews Drug Discovery, 2017). Therapeutic strategies often focus on either scavenging ROS directly or upregulating the endogenous defense system through pathways like Nrf2-Keap1, though achieving clinical efficacy remains challenging due to the dual role of ROS in physiology and pathology (Frontiers in Pharmacology, 2020).

Other names

Oxidative stress pathwayRedox homeostasis systemROS-antioxidant balanceCellular redox system

Direct scavenging of reactive species, induction of endogenous antioxidant enzymes via Nrf2 activation, or inhibition of ROS-generating enzymes such as NADPH oxidase (NOX) (Nature Reviews Drug Discovery, 2017).