Oxygen-centered radical (None commonly used; plural form "O-centered radical(s)" sometimes appears, but no standardized abbreviation)

Oxygen-centered radicals are a class of highly reactive chemical species with an unpaired electron localized on an oxygen atom, formed through partial reduction of molecular oxygen or through photochemical/electrochemical processes. They encompass superoxide (O₂•⁻), hydroxyl radical (OH•), peroxyl (ROO•), alkoxyl (RO•), and singlet oxygen (¹O₂), among others. In biological systems, they are produced during normal metabolism but can accumulate to damaging levels under stress or due to environmental exposures. Oxygen-centered radicals are not considered therapeutic targets but are pivotal in mediating cell signaling, oxidative stress, and chemical transformations. Their excessive generation is implicated in multiple diseases, including cancer, cardiovascular and neurodegenerative disorders, and aging. Drugs interacting with these radicals are generally antioxidants or agents modulating radical levels, though these molecules themselves are not the direct targets. The highly reactive nature of oxygen-centered radicals poses significant safety challenges, demanding careful control in therapeutic or experimental contexts.

Other names

Oxygen radicalO-centered radicalOxygen free radicalSuperoxide radical (O₂•⁻)Hydroxyl radical (OH•)Alkoxyl radical (RO•)Peroxyl radical (ROO•)Singlet oxygen (¹O₂)

Scavenging or quenching reactive oxygen species; Conversion of radicals to less reactive species (by antioxidant drugs); Catalysis of electron transfer or redox reactions (e.g., in photodynamic therapy)