Reactive oxygen species and electrophilic oxidants (ROS)

Reactive oxygen species (ROS) and electrophilic oxidants are a broad class of highly reactive molecules, including free radicals like superoxide (O2•−) and hydroxyl radicals (•OH), as well as non-radical oxidants like hydrogen peroxide (H2O2) and singlet oxygen (Sies et al., 2017, Nature Reviews Molecular Cell Biology). These species are primarily generated as byproducts of mitochondrial oxidative phosphorylation or through the action of enzymes such as NADPH oxidases (NOX) and xanthine oxidase (Pizzino et al., 2017, Oxidative Medicine and Cellular Longevity). In physiological conditions, they function as vital signaling molecules (redox signaling) that regulate cell growth, differentiation, and immune responses. However, an imbalance between their production and the cellular antioxidant defense systems leads to oxidative stress, which causes cumulative damage to DNA, proteins, and lipids. This damage is a central driver in the progression of various diseases, including cancer, neurodegenerative disorders (e.g., Alzheimer's and Parkinson's), and cardiovascular diseases (Schieber & Chandel, 2014, Current Biology). Pharmacological strategies to address ROS involve direct scavenging by antioxidants like Edaravone or N-acetylcysteine, or the indirect upregulation of protective enzymes via the Nrf2 pathway (e.g., Dimethyl fumarate). Despite their therapeutic potential, the non-specific nature of ROS and their requirement for normal cellular signaling make them challenging to target without disrupting essential biological processes.

Other names

Reactive oxygen speciesROSElectrophilic speciesOxidative stress mediatorsFree radicalsReactive nitrogen species (RNS)

Direct chemical scavenging of reactive species, neutralization of free radicals, or induction of the Nrf2-mediated antioxidant response element (ARE) pathway to increase endogenous antioxidant enzymes.