Reactive oxygen species and organic radicals (ROS) (ROS)

Reactive oxygen species (ROS) and organic radicals are highly reactive molecules containing oxygen or carbon with unpaired electrons, primarily generated as byproducts of mitochondrial metabolism and enzymatic activity (Sies et al., 2017). In physiological conditions, they serve as vital signaling molecules regulating cell growth, differentiation, and the immune response (Pizzino et al., 2017). However, excessive accumulation leads to oxidative stress, causing irreversible damage to DNA, proteins, and lipids, which is a key driver in the progression of chronic diseases such as cancer, Alzheimer's, and atherosclerosis (NIH, 2023). Therapeutic targeting involves the use of antioxidants and radical scavengers, such as Edaravone or N-acetylcysteine, to neutralize these species and prevent tissue damage (StatPearls, 2023). Despite their therapeutic potential, non-selective removal of ROS can interfere with necessary cellular signaling pathways, presenting a significant challenge in drug development (Halliwell, 2011). Furthermore, the use of high-dose antioxidants has occasionally been linked to increased mortality or accelerated cancer progression in specific clinical contexts.

Other names

Free radicalsOxidantsOxygen radicalsPro-oxidantsReactive oxygen speciesOrganic free radicals

Drugs targeting these species typically act through direct scavenging, where they donate electrons to neutralize unpaired electrons, or by acting as mimetics of endogenous antioxidant enzymes like superoxide dismutase and catalase (Sies et al., 2017).