Vitamin E, also known as tocopherol, is a kind of phenolic compounds with biological activity and similar chemical structure. Vitamin E is a fat-soluble vitamin, which is a derivative of benzopyran in chemical structure, including tocopherol and tocotrienols. The main structures of tocopherol and tocotrienols are hydroquinone groups plus isoprene-like side chains. The main difference between them is that the side chain of tocopherol is saturated fatty acid, while the side chain of tocopherol is unsaturated fatty acid with three double bonds, which are located at 3', 7', 1 1' positions respectively (Figure 1). Tocopherol is mainly found in corn oil, soybean oil and olive oil, while tocotrienols is rich in palm oil, rice bran oil and barley oil. There are eight kinds of vitamins known in nature, which are four isomers of α, β, γ and δ vitamins, and they are mainly divided according to the position and number of methyl substituents on benzopyran (Figure 1).