Fig. 2

Sources and fates of Reactive oxygen species (ROS) as a main cause behind lipid peroxidation. Superoxide anion (O2^●) is a chief radical produced normally during cell metabolism through the mitochondrial electron transport chain (ETC). Its oxidative effect is diffused by SOD (superoxide dismutase) which transforms it into the non-radical hydrogen peroxide (H2O2). H2O2 can also be enzymatically produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs), cytochrome P450 (CYP450), cyclooxygenases (COXs), and lipoxygenases (LOXs). H202 then can share in cell signalling processes or get neutralized through catalase and GPX (glutathione peroxidases). However, H2O2 can cause DNA and protein damage and lipid peroxidation through generating the highly reactive hydroxyl (OH^●) radical. H2O2 generates OH^● radicals through the Fenton reaction by interaction with ferrous iron (Fe⁺²)