Reactive oxygen species and related free radical species (ROS)

Reactive oxygen species (ROS) are highly reactive oxygen-containing molecules, such as superoxide radicals, hydrogen peroxide, and hydroxyl radicals, that are generated as natural byproducts of oxygen metabolism. In physiological conditions, ROS serve as vital secondary messengers in various signal transduction pathways, regulating cell growth, immune activation, and vascular tone. However, when the production of ROS exceeds the cell's antioxidant neutralizing capacity, a state of oxidative stress occurs, leading to indiscriminate damage to DNA, lipids, and proteins. This oxidative damage is a primary driver in the pathogenesis of chronic conditions including atherosclerosis, Alzheimer's disease, and various cancers. Pharmacological intervention typically involves the use of antioxidant scavengers to neutralize these species or the modulation of enzymes like NADPH oxidase and superoxide dismutase to restore redox balance. While historically viewed as toxic waste products, modern therapeutic approaches recognize the need for precise modulation to preserve beneficial signaling while preventing pathological damage.

Other names

Free radicalsOxygen radicalsPro-oxidantsReactive oxygen entitiesOxidative stress mediators

Direct scavenging of free radicals, neutralization of reactive intermediates, and enhancement of endogenous antioxidant capacity to reduce oxidative damage to cellular components.