Reactive oxygen species and antioxidant enzyme systems (ROS/Antioxidant system)

Reactive oxygen species (ROS) are highly reactive oxygen-containing molecules, such as superoxide and hydrogen peroxide, that function as critical secondary messengers in cell signaling and immune defense (PubMed: 28129551). To prevent cellular damage, the body employs a complex antioxidant enzyme system—including superoxide dismutase (SOD), catalase, and glutathione peroxidase—to neutralize excess ROS and maintain redox homeostasis (StatPearls: NBK545155). When the production of ROS exceeds the capacity of these antioxidant defenses, oxidative stress occurs, leading to damage of lipids, proteins, and DNA (NIH: PMC4310836). This imbalance is a hallmark of various pathologies, including neurodegenerative diseases, cardiovascular disorders, and cancer, where ROS can promote genomic instability. Therapeutic interventions targeting this system include direct antioxidants and Nrf2 activators that boost the expression of multiple antioxidant enzymes, though clinical application remains challenging due to the dual role of ROS in both health and disease (Nature Reviews Drug Discovery: 10.1038/nrd.2017.243).

Other names

Oxidative stress pathwayRedox homeostasis systemROS scavenging systemAntioxidant defense systemRedox signaling network

Direct scavenging of reactive species, induction of endogenous antioxidant enzymes via the Nrf2-KEAP1 pathway, and enzymatic conversion of superoxide and peroxides into less reactive molecules.