Lipid peroxyl radical in phospholipid bilayer

Lipid peroxyl radicals (LOO•) are unstable, highly reactive chemical species generated during the process of lipid peroxidation, in which reactive oxygen species attack unsaturated fatty acids—primarily polyunsaturated fatty acids—in phospholipid bilayers of cell membranes[5][6]. These radicals are chain-propagating intermediates that facilitate the continuation of lipid peroxidation and ultimately lead to substantial changes in membrane structure, fluidity, and integrity[1][2][3][4][5][6]. Formation of lipid peroxyl radicals and their accumulation contribute to oxidative damage implicated in various pathologies, including neurodegenerative diseases, cardiovascular disorders, inflammation, cancer, and cell aging[5][6]. Antioxidant molecules such as vitamin E and enzymatic systems including glutathione peroxidase act to intercept lipid peroxyl radicals, limiting lipid peroxidation and preserving membrane function[5][6]. Lipid peroxyl radicals themselves are not therapeutic drug targets but are critical mediators of damage; thus, the therapeutic strategy is often to prevent their formation or neutralize them with antioxidants[5][6]. Detection of their stable byproducts (e.g., MDA, 4-HNE, isoprostanes) serves as biomarkers of oxidative stress and lipid peroxidation[6]. In research contexts, molecular simulations reveal that these radicals reside deep within the lipid bilayer, affecting membrane properties such as permeability and lateral organization, rather than floating at the membrane surface[2][3][4].

Other names

lipid peroxyl radicalperoxyl radicalLOO•lipid peroxidation intermediatephospholipid peroxyl radical

Scavenging of lipid peroxyl radicals by antioxidants to terminate lipid peroxidation chains; Enzymatic reduction of peroxyl radicals (e.g., by glutathione peroxidase 4)