tocopherol

(redirected from alpha-tocopherol)
Also found in: Dictionary, Thesaurus, Medical.

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.
..... Click the link for more information.
.

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 ?
Unlike authors of the 2005 meta-analysis that indicated that doses [great than or equal to]400 IU/d increased all-cause mortality risk, these researchers found no evidence that alpha-tocopherol increases mortality in this population: "The annual mortality rate was 7.
The release of alpha-tocopherol and quercetin from LLDPE films into coconut oil at 30 C was quantified by high-performance liquid chromatography for four weeks.
Alpha-tocopherol is also an important factor to improve the fertilization and hatching performance of shrimp eggs.
On the other hand, we can account for less than 5 percent of the daily intake of alpha-tocopherol through urinary excretion.
Ronotec 202 liquid USP alpha-tocopherol (vitamin E) provides good processing and color stability.
Seeks Minimum Replenishment of alpha-Tocopherol (vitamin E) in Cigarettes.
In a previous study, 2000 IU per day of alpha-tocopherol slowed disease progression in patients with moderately severe Alzheimer's disease.
Rats were randomly divided into 4 equal groups of 15 rats each; Group 1 acted as control and received regular chow that contained a small amount of alpha-tocopherol to support rat's health; Group 2 received local heart irradiation and regular chow; Group 3 received local heart irradiation and 3 months later was fed PTX-enriched chow; and Group 4 received local heart irradiation and 3 months later was fed with PTX-enriched and Tocomin SupraBio chow.
OBJECTIVE: To determine the effect of ascorbic acid and alpha-tocopherol on oxidative stress and bone mineral density (BMD) in elderly people.
Researchers looked at a number of other antioxidants-alpha-carotene, beta-carotene, alpha-tocopherol, which is a form of vitamin E, and vitamin A, or retinol-but did not find any link with stroke risk.
Recently, in one of the largest prostate cancer clinical trials in the United States and Canada, scientists found that the most commonly used form of vitamin E supplements, alpha-tocopherol, not only did not prevent prostate cancer, but its use significantly increased the risk of this disease among healthy men.
Alpha-tocopherol was the focus of early research and is the most common form of vitamin E.