Reactive oxygen species and electrophilic radicals (ROS)

Reactive oxygen species (ROS) and electrophilic radicals are highly reactive chemical entities, including superoxide anions, hydroxyl radicals, and hydrogen peroxide, that are generated as natural byproducts of oxygen metabolism (Sies & Jones, 2020, Nature Reviews Molecular Cell Biology). They serve critical roles in cellular physiology, acting as signaling molecules in pathways such as the mitogen-activated protein kinase (MAPK) cascade and the immune system's oxidative burst to eliminate pathogens (Pizzino et al., 2017, Oxidative Medicine and Cellular Longevity). However, an imbalance between ROS production and the body's antioxidant defense mechanisms leads to oxidative stress, which causes oxidative damage to lipids, proteins, and nucleic acids (Halliwell & Gutteridge, 2015, Free Radicals in Biology and Medicine). This molecular damage is implicated in the pathogenesis of numerous conditions, including cancer, cardiovascular diseases, and neurodegenerative disorders like Amyotrophic Lateral Sclerosis (ALS) (Pizzino et al., 2017). Pharmacological intervention typically involves the use of antioxidant scavengers, such as N-acetylcysteine or edaravone, which neutralize these species to prevent cellular injury (PubChem CID 12035; CID 4021). Despite their therapeutic potential, targeting ROS is complex because complete suppression can interfere with essential redox-sensitive signaling processes (Sies & Jones, 2020).

Other names

Free radicalsReactive nitrogen speciesRNSOxidantsElectrophilic speciesReactive oxygen intermediates

Direct chemical neutralization (scavenging) of free radicals, enhancement of endogenous antioxidant capacity (e.g., glutathione replenishment), and modulation of redox-sensitive transcription factors like Nrf2 (Halliwell & Gutteridge, 2015, Free Radicals in Biology and Medicine; PubChem).