tocopherol


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Related to tocopherol: vitamin E

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 ?
Significant or highly significant genotypic differences occurred for all traits, but genotype x environment interaction effects were always larger than the genotypic variance except for total tocopherol content in Population 3.
Comparison animal studies investigated the impact of tocotrienol supplementation vis-a-vis tocopherol or nonsupplementation in atheroma formation.
In a 2007 publication, a long-standing expert on tocopherols concluded that alpha-tocopherol was an "antioxidant, and nothing more.
Copper-induced LDL peroxidation: interrelated dependencies of the kinetics on the concentrations of copper, hydroperoxides and tocopherol.
Tocopherols have a longer tail, whereas tocotrienols have a shorter, agile tail for heightened mobility.
If high-dose alpha-tocopherol does adversely affect cardiac function in some people, one might reasonably expect that mixed tocopherols, which contain all four isomers of vitamin E, would not have the same negative effects, and might even be beneficial.
2011) highlight the presence of antioxidant compounds such as flavonoids and tocopherols in nut; the latter may reduce the risk of heart disease, type 2 diabetes and cancer (KOKSAL et al.
Improved adzuki bean genotypes had a higher total tocopherol concentration compared to wild and landrace genotypes; differences between improvements status groups being observed for tocopherols except (alpha)-tocopherol.
Efficacy of intrauterine use of levofloxacin and alpha tocopherol on conception rate in repeat breeder crossbred cows.
Breeding soybeans to increase tocopherol levels (mainly [alpha] and [gamma]-tocopherol) is considered important for nutritional and functional concerns regarding food stability and human health.