Reactive oxygen species and pro-oxidant systems (ROS)

Reactive oxygen species (ROS) and pro-oxidant systems represent a broad category of highly reactive oxygen-containing molecules and the enzymatic pathways that generate them, such as NADPH oxidases (NOX), xanthine oxidase, and the mitochondrial respiratory chain. Under physiological conditions, ROS act as critical secondary messengers in signal transduction and are essential for the immune system's ability to neutralize pathogens through the oxidative burst. However, an imbalance where ROS production exceeds the capacity of antioxidant defense mechanisms leads to oxidative stress, resulting in oxidative damage to DNA, lipids, and proteins. This damage is a central driver in the progression of various pathologies, including atherosclerosis, Parkinson's disease, and various cancers. Therapeutic interventions aim to mitigate this damage either by using antioxidant scavengers to neutralize existing radicals or by inhibiting the specific pro-oxidant enzymes responsible for their overproduction. Because ROS are involved in both vital signaling and pathological damage, therapeutic targeting requires precision to avoid interfering with necessary cellular functions.

Other names

Reactive oxygen speciesFree radicalsOxidantsReactive nitrogen speciesPro-oxidantsOxidative stress mediators

Drugs targeting these systems typically act by directly scavenging free radicals, inhibiting ROS-generating enzymes such as NADPH oxidase or xanthine oxidase, or inducing endogenous antioxidant enzymes through pathways like Nrf2 activation.