Superoxide anion radical (O₂•⁻)

Superoxide anion radical (O₂•⁻) is a small, highly reactive oxygen species classified as a free radical and forms through the one-electron reduction of molecular oxygen, primarily during mitochondrial respiration, enzymatic cascades, and oxidative bursts in immune cells. It is not a protein or macromolecular drug target, but rather a transient chemical species central to redox biology and implicated in both normal cellular signaling and numerous pathological states. Though it acts as a signaling molecule at low concentrations, elevated superoxide contributes to tissue injury in many diseases via oxidative modification of biomolecules. Cellular defense mechanisms such as superoxide dismutases (SODs) rapidly convert O₂•⁻ into less reactive species, underscoring its hazardous potential and lack of suitability as a direct therapeutic target. Therefore, "superoxide radical" is not considered a canonical drug target (such as a receptor or enzyme), but rather a key reactive molecule with broad biological and pathological relevance.

Other names

superoxide radicalsuperoxideO2•–O2^•−dioxide(1–)hyperoxidesuperoxide ion