Reactive oxygen species and lipid-derived free radicals (ROS/LFR)

Reactive oxygen species (ROS) and lipid-derived free radicals are highly reactive, oxygen-containing molecules and lipid-based intermediates that possess unpaired electrons. They are generated as natural byproducts of mitochondrial respiration, enzymatic reactions such as those involving NADPH oxidases, and environmental exposures like radiation (Pizzino et al., 2017, Oxidative Medicine and Cellular Longevity). At physiological levels, these species function as critical signaling molecules in processes like cell proliferation, differentiation, and the immune "respiratory burst" used to kill pathogens (Sies et al., 2017, Nature Reviews Molecular Cell Biology). However, excessive accumulation leads to oxidative stress, causing irreversible damage to cellular macromolecules, including DNA mutations, protein carbonylation, and lipid peroxidation (Ayala et al., 2014, Oxidative Medicine and Cellular Longevity). This damage is a hallmark of aging and is central to the progression of neurodegenerative diseases like Alzheimer's, cardiovascular conditions like atherosclerosis, and various cancers. Pharmacological intervention typically involves radical scavengers or antioxidants that neutralize these species to prevent cellular injury, though maintaining the delicate balance of redox homeostasis remains a significant therapeutic challenge.

Other names

Reactive oxygen speciesFree radicalsLipid peroxyl radicalsOxidantsOxygen-derived free radicalsLipid-derived radicalsReactive oxygen intermediates

Direct chemical neutralization (scavenging) of unpaired electrons, reduction of reactive intermediates to stable forms, and enhancement of endogenous antioxidant enzyme systems.