Vitamin E (Tocopherol): Biosynthesis, Biological roles and Deficiency

Gaurab Karki — Tue, 21 Jul 2020 11:40:07 +0000

Vitamin E is also termed as anti-sterility vitamin
It is a very powerful biological antioxidant.
It is a common term for a group of closely related lipids called as tocopherols.
It is also called as vitamin in search of disease. It is because disease associated with its deficiency is yet unknown.
Some of the common forms of Vitamin E are as follows:
- α-tocopherol = 5,7,8-trimethyltocol
- β-tocopherol = 5,8-dimethyltocol
- γ-tocopherol = 7,8-dimethyltocol
- 𝛿-tocopherol= 2,8-dimethyltocol
Vitamin E is observed in presence of bile salt from the intestine.
It is incorporated into lipoproteins, LDL and VLDL and stored in muscles, liver and adipose tissue.

Biosynthesis of Vitamin E:

The major functions of vitamin E are confined to flowing aspects:
Maintenance of normal cell membrane:
- Vitamin E is responsible for maintaining the integrity of cell membrane by preventing the oxidation of polyunsaturated fatty acid by the effect of super-oxides, peroxide and other free radicals.
- Vitamin E prevents the hemolysis of RBCs by preventing the oxidation of unsaturated fatty acids in erythrocytes membrane.
Role in metabolism:
- Vitamin E have been found involved in synthesis of nucleic acid.
- It is also engaged in storage of keratin in membrane and absorption of aminoacids in intestine.
Reproduction:
- Vitamin E is an anti-sterility vitamin.
- It maintains the normal germinal epithelium of the gonads.
Prevention of cataract and heart disease:
- Vitamin E prevent the oxidation of vitamin A (-carotene).
- Therefore, prevent the risk of cancer associated with the free radicals, super-oxides, peroxides.
- Vitamin-E along with A and C is involved in the prevention of cataract and heart disease.
Heme synthesis:
- Vitamin E is required for the activity of delta-aminolevulinic acid which is required for the synthesis of Heme from the condensation of glycine and succinyl coA.
Role in respiration:
- Co-enzyme Q (Ubiquinone) in membrane is stabilized by vitamin E and therefore aids in cellular respiration.

Vegetables are rich source in vitamin E.
Wheat germ oil, peanut oil, soyabean oil, corn oil, cotton seed oil, are rich source of Vitamin E.
Butter, milk, meat, egg are also sources of Vitamin E.

Vitamin E as mentioned earlier is called as vitamin in search of disease.
Due to deficiency of vitamin E in humans, fragile erythrocytes, abnormal cell membrane and minor neurological sign are observed.
In cases of mature female rats, sterility is observed whereas in male rats, the germinal epithelium of testes degenerates and spermatozoa becomes non-motile.