Lipid peroxidation

Lipid peroxidation is the oxidative degradation of lipids, especially polyunsaturated fatty acids. It proceeds through radical chain reactions that can damage membranes and generate reactive breakdown products.

Reactive oxygen species: Reactive oxygen species are oxygen-containing molecules that readily participate in oxidation reactions. They can initiate lipid oxidation by abstracting hydrogen atoms from susceptible fatty acids.
Polyunsaturated fatty acid: A polyunsaturated fatty acid contains two or more carbon–carbon double bonds. Its bis-allylic hydrogens are especially easy to remove, making it a major peroxidation target.
Malondialdehyde: Malondialdehyde is a reactive dialdehyde formed during breakdown of certain peroxidized polyunsaturated fatty acids. Its abundance is often measured as an indicator of lipid oxidative damage.
Enzymatic lipid oxidation: Enzymatic lipid oxidation is the regulated oxygenation of lipids by enzymes such as lipoxygenases and cyclooxygenases. Unlike spontaneous radical-chain damage, it can produce specific signaling molecules through enzyme-controlled reactions.
Lipid radical: A lipid radical is a lipid molecule with an unpaired electron, formed when a hydrogen atom is removed. It is the chain-carrying intermediate that reacts rapidly with oxygen.
Bis-allylic position: A bis-allylic position is a carbon between two double bonds in a polyunsaturated fatty acid. The hydrogen attached there is unusually vulnerable to radical abstraction.
4-Hydroxynonenal: 4-Hydroxynonenal is a reactive aldehyde produced during peroxidation of omega-6 polyunsaturated fatty acids. It can modify proteins and influence signaling after membrane lipid oxidation.
Lipid autoxidation: Lipid autoxidation is the spontaneous radical-chain reaction of lipids with oxygen, often accelerated by heat or light. It is the nonenzymatic chemical process underlying much lipid peroxidation in foods and tissues.
Lipid hydroperoxide: A lipid hydroperoxide is an oxidized lipid containing an –OOH group. It is the primary product of oxygen addition during chain propagation.
Phospholipid: A phospholipid is an amphipathic lipid with a phosphate-containing head group and hydrophobic tails. Polyunsaturated phospholipid tails are common substrates in cellular membranes.

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