Reactive oxygen species and oxidized antioxidant pools (ROS)

Reactive oxygen species (ROS) are highly reactive chemical species, including superoxide, hydrogen peroxide, and hydroxyl radicals, that are formed as natural byproducts of oxygen metabolism (Sies et al., 2017, Nature Reviews Molecular Cell Biology). Under physiological conditions, they serve as critical signaling molecules for cell growth, differentiation, and the immune response; however, an imbalance between ROS production and the body's antioxidant defenses leads to oxidative stress (Ray et al., 2012, Cell Signaling). The 'oxidized antioxidant pool' refers to the depletion of endogenous reducing agents, such as the conversion of reduced glutathione (GSH) to its oxidized form (GSSG), which occurs when ROS levels overwhelm cellular capacity (Frijhoff et al., 2015, Antioxidants & Redox Signaling). This state of oxidative stress causes cumulative damage to DNA, proteins, and lipids, contributing to the pathogenesis of cancer, neurodegeneration, and cardiovascular diseases (PubMed, PMID: 22226774). Therapeutic strategies involve using antioxidants or scavengers like N-acetylcysteine or edaravone to neutralize these species or replenish the antioxidant pools (DrugBank; FDA). Despite their therapeutic potential, targeting ROS is challenging because non-selective scavenging can disrupt vital redox-sensitive signaling pathways, often leading to limited efficacy in clinical trials (NIH, National Center for Complementary and Integrative Health).

Other names

Free radicalsOxidantsOxygen radicalsPro-oxidantsOxidative stress mediatorsReactive oxygen metabolites

Direct chemical scavenging of free radicals, neutralization of reactive oxygen intermediates, and restoration of the reduced state of endogenous antioxidant pools such as the glutathione and thioredoxin systems.