Reactive oxygen species formation pathway (ROS formation pathway)

The *reactive oxygen species formation pathway* refers collectively to all cellular mechanisms responsible for generating reactive oxygen species—highly reactive molecules derived from molecular oxygen—including superoxide anion (O_2^-), hydrogen peroxide (H_2O_2), hydroxyl radical (^.OH), among others. The primary sources are mitochondrial electron transport chain complexes I and III during aerobic respiration; other contributors include NADPH oxidases in membranes, monoamine oxidase in mitochondria, cytochrome b5 reductase, dihydroorotate dehydrogenase, and various peroxisomal/cytoplasmic enzymes[1][3]. While low/moderate levels play crucial roles in physiological signaling—such as immune defense modulation and regulation of hematopoiesis—excessive accumulation leads to oxidative damage implicated in aging-related diseases including cancer, neurodegeneration, cardiovascular disorders, inflammation-driven pathologies,[1][3] ischemia-reperfusion injury,[4] among others. Because this term encompasses many proteins/enzymes/processes rather than one discrete druggable entity,[1] it should not be considered a canonical therapeutic target but rather an important biological context influencing drug action across diverse fields.

Other names

ROS generation pathwayOxidative stress pathwayMitochondrial ROS production

Drugs acting on this system generally: Scavenge free radicals/ROS directly; Inhibit key enzymes responsible for generating superoxide/hydrogen peroxide (e.g., NOX inhibitors); Enhance endogenous antioxidant defenses by upregulating glutathione synthesis or related systems.