Antioxidant activity against reactive oxygen species

"Antioxidant activity against reactive oxygen species" does **not** refer to a single molecular target such as an enzyme or receptor but rather describes the collective ability of various molecules—both enzymatic and nonenzymatic—to neutralize reactive oxygen species (ROS) within cells. ROS are highly reactive derivatives of oxygen that play dual roles in biology: at low concentrations they function in cell signaling; at high concentrations they cause cellular damage leading to lipid peroxidation, protein modification, DNA/RNA oxidation, enzyme inhibition, apoptosis activation—and ultimately contribute to aging and many diseases if not adequately controlled by antioxidants. The main enzymatic antioxidants include superoxide dismutases (SODs), catalases, peroxidases such as glutathione peroxidase; nonenzymatic antioxidants include molecules like ascorbic acid (vitamin C), tocopherols/tocotrienols (vitamin E), glutathione (GSH), flavonoids like quercetin/curcumin. These systems work together in complex cycles—such as the water-water cycle or Asc-GSH cycle—to maintain redox balance within different subcellular compartments. Because "antioxidant activity against reactive oxygen species" is not itself a discrete molecular entity but rather an emergent property arising from multiple biochemical systems acting together across various tissues/cell types/organisms—it should **not** be considered a canonical therapeutic target for drug discovery purposes.[1][3]

Other names

Antioxidant defense against ROSAntioxidative system (AOS)ROS scavenging activityCellular antioxidant capacity

Antioxidants act by neutralizing reactive oxygen species through electron donation or hydrogen atom transfer, thereby preventing oxidative damage to cellular components such as lipids, proteins, and nucleic acids. Some antioxidants also upregulate endogenous antioxidant enzymes or modulate redox-sensitive signaling pathways like Keap1-Nrf2.[1][2][3][5]