Reactive oxygen species and free radicals (ROS) (ROS)

Reactive oxygen species (ROS) and free radicals are a diverse group of highly reactive oxygen-containing molecules, such as superoxide, hydroxyl radicals, and hydrogen peroxide, characterized by the presence of unpaired electrons (Phaniendra et al., 2015). They are primarily generated as byproducts of mitochondrial aerobic respiration and by specific enzymes like NADPH oxidases during the immune response (Sies & Jones, 2020). While they serve essential roles as secondary messengers in cell signaling and homeostasis at low levels, an imbalance between their production and the body's antioxidant defenses leads to oxidative stress (Pizzino et al., 2017). This state results in oxidative damage to cellular macromolecules, including DNA, lipids, and proteins, contributing significantly to the pathogenesis of cancer, neurodegeneration, and cardiovascular diseases (NIH/NCI). Pharmacological intervention typically involves the use of antioxidants or radical scavengers designed to neutralize these species and mitigate tissue damage. However, the therapeutic application of these agents is often limited by the need to maintain basal ROS levels for normal physiological functions (StatPearls).

Other names

Free radicalsOxidantsReactive nitrogen speciesRNSReactive oxygen intermediatesPro-oxidants

Direct chemical scavenging and neutralization of reactive oxygen and nitrogen species to prevent macromolecular damage (Pizzino et al., 2017).