Vitamin E occurs in nature in at least eight different isoforms: α, β, γ -and 𝛿 -tocopherols and α, β, γ- and 𝛿 -tocotrienols. Tocotrienols differ from the corresponding tocopherols only in their aliphatic tail. Free radical scavenging reactions of α tocopherol take place via the α -tocopheroxyl radical as an intermediate.
Tocopherol isomers are chain-breaking antioxidants. α-tocopherol, the most biologically active and abundant form of vitamin E in vivo, efficiently transfers a hydrogen atom to a lipid free radical, such as peroxyl, alkoxyl, and carbon~centered radicals, giving the corresponding non-radical product of the lipid and an α -tocopheroxyl radical.
Most notably, vitamin E prevents the oxidation of the polyunsaturated fatty acids, but is protects other lipids and related components (e.g. vitamin A) as well. It therefore occupies a unique position in the arsenal of natural antioxidants providing protection against various diseases.
Mechanism of vitamin E as antioxidant
