beta-tocopherol is one of the forms of vitamin E, which is well known for its antioxidant activity.1,2 beta-tocopherol, due to its having only one methyl group ortho to the phenolic hydroxyl group, has slightly less antioxidant activity in vivo than alpha-tocopherol which has two ortho-methyl groups. Vitamin E inhibits lipid oxidation by donating its phenolic hydrogen to lipid free radicals.3 Antioxidant activity in vivo is normally lpha>beta>delta>gamma but the antioxidant potency may depend on various chemical and physical situations.4 The ortho-methyl substitution of the chroman head plays a vital role in the antioxidant activity of tocopherols while the phytyl tail is very important for proper positioning in the biomembranes. The antioxidant properties of vitamin E may delay memory loss in Down’s syndrome patients due to their protection from harmful oxidation caused by excess activity of Superoxide dismutase. Vitamin E is only naturally produced in plants, algae, and some cyanobacteria and is therefore an important dietary nutrient for humans and animals.
