Reactive oxygen species and free radical species (ROS) (ROS)

Reactive oxygen species (ROS) and free radical species are highly reactive chemical entities, often containing oxygen or nitrogen with unpaired valence electrons, that are generated as natural byproducts of cellular metabolism, particularly within the mitochondria (NIH, 2023). At physiological levels, they function as vital signaling molecules in processes such as cell proliferation, differentiation, and the immune system's oxidative burst used to kill pathogens (StatPearls, 2023). However, an imbalance known as oxidative stress occurs when ROS production exceeds the capacity of endogenous antioxidant systems, leading to oxidative damage of DNA, lipids, and proteins (PubMed, 2022). This damage is a central driver in the progression of various conditions, including cardiovascular diseases, neurodegeneration, and cancer (Nature Reviews, 2021). Pharmacological intervention typically involves the use of antioxidants or radical scavengers to neutralize these species or the activation of transcription factors like Nrf2 to bolster the cell's natural defenses (Journal of Biological Chemistry, 2020).

Other names

ROSFree radicalsReactive nitrogen speciesRNSOxidantsSuperoxideHydroxyl radicalHydrogen peroxideSinglet oxygen

Direct chemical neutralization (scavenging) of reactive species, chelation of metal ions to prevent radical formation, and induction of endogenous antioxidant enzymes via the Nrf2/ARE pathway (StatPearls, 2023; PubMed, 2022).