tocopherol

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tocopherol:

see vitaminvitamin,
group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
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Tocopherol

 

any vitamin of the E group. Tocopherols are similar in chemical structure and are contained in large quantities in vegetable oils. Eight tocopherols that have vitamin activity are known; they are designated by the Greek letters et, β, 7, and so on. Although only a tocopherol, which is the most active, was formerly considered to be vitamin E, the term subsequently came to include the entire group of natural and synthetic tocopherols, which have the activity of α-tocopherol to varying degrees (α-tocopherol was discovered in the 1920’s and was extracted in pure form in 1936; P. Karrer synthesized it chemically in 1938).

Chemically, tocopherols are derivatives of chromane (a two-ring aromatic system) combined with an isoprenoid side chain. Tocopherols are transparent, oily liquids that are soluble only in organic solvents; they remain stable upon heating. They are widespread in nature but are synthesized only by plants. Animals and man obtain them from food. The highest tocopherol content is found in the germs of cereals and in the oils extracted from them. With a normal diet, E avitaminosis and hypovitaminosis occur rarely. Insufficient intake of vitamin E in experimental animals leads to sterility, muscular dystrophy, disorders of the central nervous system, increased hemolysis, and hypothyroidism. Tocopherol deficiency causes increased permeability or complete disintegration of biological membranes, including the membranes of the mitochondria and lysosomes. It is assumed that one of the functions of tocopherols in cells is to prevent the formation of peroxides from unsaturated fatty acids—that is, to play the role of natural antioxidants. In many cases, pathological symptoms that result from a tocopherol-deficient diet may be eliminated or prevented by certain antioxidants. The biochemical functions of tocopherols are also associated with tissue respiration processes.

Tocopherols are used in medicine to treat certain nervous, skin, gynecological, and cardiovascular disorders. Supplements added to animal feeds sharply reduce miscarriages in cows and eliminate motor disorders and paralyses in young birds. Tocopherols are used as natural antioxidants to stabilize vitamins A and D and to prevent vegetable oils from becoming rancid.

REFERENCE

Shaternikov, V. A. “Vitamin E.” In Vitaminy. Moscow, 1974. Chapter 5.

N. N. ZAITSEVA

tocopherol

[tə′käf·ə‚röl]
(organic chemistry)
Any of several substances having vitamin E activity that occur naturally in certain oils; α-tocopherol possesses the highest biological activity.
References in periodicals archive ?
Cardiovascular Health & Anti-Inflammation: Clinical studies have shown that tocotrienols-when taken apart from alpha-tocopherol (due to interference issues)-lower total cholesterol, LDL, and triglyceride levels between 15-20%.
The importance of considering gamma-tocopherol in human nutrition is underscored by reports that supplementation with alpha-tocopherol in doses of 200-1,200 IU per day decreased serum levels of gamma-tocopherol by accelerating its metabolism.
studied whether one application of an alpha-tocopherol-enriched rinse-off product could effectively lead to deposition of alpha-tocopherol on the SC in 13 volunteers.
Kivipelto said vitamin E supplements available on the market usually contain only alpha-tocopherol, and the best sources of vitamin E are vegetable oils, nuts, green vegetables and whole grain cereals.
The bactericidal activity of Levofloxacin and immune stimulant activity of Alpha-tocopherol is the basis for superior efficacy in treatment bovine endometritis.
Alpha-Tocopherol in human spermatozoa and seminal plasma: relationships with motility, antioxidant enzymes and leukocytes.
There were small but significant increases in the proportion of alpha-tocopherol in beans from the same genetic line grown in warmer, full-season Eastern Shore locations compared to beans that matured under slightly cooler conditions.
5-fold increase in relative alpha-tocopherol content, compared to the other years during which rainfall was adequate.
The scientists attempted to form and characterize cyclodextrin inclusion complexes with the natural antioxidants alpha-tocopherol and quercetin.
5 IU per day is the recommended daily dose of the alpha-tocopherol form of vitamin E.