The vitamin E family of compounds consists of a group of eight molecules belonging to two classes designated as tocopherols, and tocotrienols.
Seven closely related tocopherol compounds are known to occur in nature; they are identified by the prefix alpha, beta, gamma, delta, etc.
α-tocopherol is the only from of vitamin E that is actively maintained in the human body, so it is the form of vitamin E found in the largest quantities in blood and tissues. It plays an essential role as an antioxidant to enhance the immune response.
Tocopherols are the most widely distributed antioxidants in nature, and are the principal antioxidants in vegetable oils. Small amounts may be detected in animal fats, originating from the vegetable components of the animal’s diets.
As a result of their long alkyl chain, tocopherol are fat soluble, and are easily dispersed in fats and oil.
The tocopherols act as antioxidants by breaking free radical chain reactions as a result of their ability to transfer phenolic hydrogen to a peroxyl free radical of a peroxidized polyunsaturated fatty acid.
Vitamin E physiological activity decreases from alpha to delta homologs, while antioxidant activity increases in this order.
All naturally occurring tocopherols occur in the D form, whereas synthetic tocopherols contain a 50/50 mixture of the D and L isomers.
Naturally occurring tocopherols are easily oxidized under adverse conditions. Tocopherols are heat sensitive and thus may be lost during processing operations.
Tocopherols are found to have a significant effect in attenuating the critical steps in the formation of atherosclerosis.
Some experimental studies have demonstrated the retardant effect of vitamin E in the progression of atherosclerosis lesions and that different isoforms of tocopherols have differential effects on key pathophysiological processes.
Tocopherols of vitamin E
