Superoxide anion and related reactive oxygen species (ROS)

Superoxide anion (O2•−) is a highly reactive free radical and a primary member of the reactive oxygen species (ROS) family, primarily generated as a byproduct of mitochondrial electron transport or by specialized enzymes such as NADPH oxidases (Sies et al., 2017, Nature Reviews Molecular Cell Biology). In physiological conditions, these molecules function as critical secondary messengers in signal transduction pathways and are essential for the oxidative burst used by phagocytes to eliminate pathogens (Lambeth, 2004, Nature Reviews Immunology). However, an overproduction of ROS or a deficiency in antioxidant defenses leads to oxidative stress, which causes oxidative damage to cellular macromolecules including DNA, proteins, and lipids. This damage is a central driver in the progression of numerous pathologies, such as atherosclerosis, Alzheimer's disease, and various cancers (Halliwell & Gutteridge, 2015, Free Radicals in Biology and Medicine). Therapeutic interventions, such as Edaravone for ALS or SOD mimetics like Avasopasem manganese, aim to mitigate this damage through the use of antioxidant scavengers or enzyme mimetics that neutralize ROS (Batinic-Haberle et al., 2010, Antioxidants & Redox Signaling). Despite their therapeutic potential, maintaining the delicate balance of redox homeostasis remains a significant clinical challenge because non-selective removal of ROS can interfere with vital cellular signaling.

Other names

Superoxide radicalReactive oxygen speciesO2•-Hydroxyl radicalHydrogen peroxideOxidative stress mediators

Drugs targeting these species typically act as chemical scavengers that directly neutralize free radicals, or as catalytic mimetics of endogenous antioxidant enzymes like superoxide dismutase (SOD) to accelerate the conversion of superoxide into less reactive molecules like oxygen and hydrogen peroxide.