Natural alpha tocopherol

The term vitamin E describes a family of eight antioxidants, four tocopherols, alpha (a), beta ((3), gamma (y) and delta (8), and four tocotrienols (also a, (3, y, and 8). a-Tocopherol is present in nature in only one form, RRR a-tocopherol. The chemical synthesis of a-tocopherol results in eight different forms (SRR, SSR, SRS, SSS, RSR, RRS, RSS, RRR), only one of which is RRR a-tocopherol. These forms differ in that they can be right (R) or left (S) at three different places in the a-tocopherol molecule. RRR a-tocopherol is the only form of vitamin E that is actively maintained in the human body and is therefore the form of vitamin E found in the largest quantities in the blood and tissue. A protein synthesized in the liver (a-TTP alpha-tocopherol transfer protein) preferentially selects the natural form of vitamin E (RRR a-tocopherol) for distribution to the tissues. However, the mechanisms for the regulation of vitamin E in tissues are not known... 

Andrikopoulos et al. (124) separated triglycerides, together with nine synthetic phenolic antioxidants most commonly used to prevent oxidation of edible oils and fats, as well as the natural antioxidants tocopherol and alpha-tocopherol acetate by HPLC using a reversed-phase Cl8 column and gradient elution with water/acetonitrile/methanol/isopropanol. Except for dilution of the oil with isopropanol/hexane, no further sample preparation was required. Ultraviolet detection was applied. The synthetic antioxidants PG, OG, DG, BHA, TBHQ, BHT, Ionox 100, THBP, and NDGA, as well as alpha- and delta-tocopherol and alpha-tocopherol acetate were separated. 

Burton, G.W. et al., Eluman plasma and tissue alpha-tocopherol concentrations in response to supplementation with deuterated natural and synthetic vitamin E, Am. J. Clin. Nutr., 67, 669, 1998. 

When Rx, and R3 are methyl groups, the compound is called alpha-tocopherol. Several other tocopherols, where Rv R2, or R3 are H-residues, are found in nature they may not be as active biologically as alpha-tocopherol. 

Hamzawi, L.F. 1990. Role of phospholipids and alpha-tocopherol as natural antioxidants in buffalo butterfat. Milchwissenschaft. 45, 95-97. 

Hoppe PP and Krennrich G (2000) Bioavailability and potency of natural-source and all-racemlc alpha-tocopherol in the human a dispute. European Journal of Nutrition 39, 183-93. 

Alpha tocopherol (vitamin E), a naturally occurring antioxidant, delays disease onset in SODl transgenic mice (Gurney et al., 1996). One epidemiological study suggested that regular intake of vitamin E may reduce the risk of contracting ALS (Ascherio et al., 2005). A randomized, placebo controlled trial of vitamin E 500 mg twice daily showed... 

Mabile, L., Bruckdorfer, K. R., and Rice-Evans, C. (1999) Moderate supplementation with natural alpha-tocopherol decreases platelet aggregation and low-density lipoprotein oxidation. Atherosclerosis 147, 177-85. 

Note that alpha tocopherol has three chiral centers, giving rise to eight isomeric forms. The naturally occurring form is known as d-alpha tocopherol or (2R,4 R,8 R)-alpha-toco-pherol. The synthetic form, d/-alpha tocopherol or simply alpha tocopherol, occurs as a racemic mixture containing equimolar quantities of all the isomers. 

Alpha tocopherol is a natural product. The PhEur 2005 (Suppl. 5.1) describes a-tocopherol as a clear, colorless or yellowish-brown, viscous, oily liquid. See also Section 17. 

Naturally occurring tocopherols are obtained by the extraction or molecular distillation of steam distillates of vegetable oils for example, alpha tocopherol occurs in concentrations of 0.1-0.3% in corn, rapeseed, soybean, sunflower, and wheat germ oils. Beta and gamma tocopherol are usually found in natural sources along with alpha tocopherol. Racemic synthetic tocopherols may be prepared by the condensation of the appropriate methylated hydroquinone with racemic isophy-tol.<">... 

Synonyms natural alpha tocopherol (-l-)-(2R,4 R,8 R)-2,5,7,8-tetramethyl-2-(4, 8, 12 -trimethyltridecyl)-6-chro-manol d-a-tocopherol vitamin E. 

Comments d-alpha tocopherol is the naturally occurring form of alpha tocopherol. 

Comments less active biologically than alpha tocopherol. Obtained along with alpha tocopherol and gamma tocopherol from natural sources. Beta tocopherol is very stable to heat and alkalis and is slowly oxidized by atmospheric oxygen. 

Comments occurs in natural sources along with alpha and beta tocopherol. Gamma tocopherol is biologically less active than alpha tocopherol. Very stable to heat and alkalis slowly oxidized by atmospheric oxygen and gradually darkens on exposure to light. 

Although bacteria present in rotifer cultures can provide vitamin B (Yu et al, 1989) and microalgae such as Chlorella sp. and I. galbana provide vitamin C (Merchie et al, 1995), extra enrichment of thiamine (as thiamine HCl) and vitamin E (as DL-alpha-tocopherol) led to an increased concentration in the rotifers after four days. On the other hand, addition of vitamin A (as retinyl palmitate) in the diet did not lead to a significant increase in vitamin A content (Srivastava et al, 2011). As copepods and their naupUi are the natural food for many marine larvae, rotifers are also enriched in iodine in order to obtain iodine levels similar to those of copepods (Srivastava et al, 2006). 

The course of the oxidation of any animal fat follows a typical pattern. A period of very limited oxygen uptake (the induction period) is followed by a phase of rapid oxidation (see Fig. 4). The induction period is due to the presence in animal fats of varying amounts of a natural antioxidant, alpha tocopherol. The activity of this and other antioxidants is discussed in Section V. 

The inherent characteristics of the fat which have an effect on rancidity have been established. They are (1) the fatty acid composition, particularly the number of active methylene groups between rmsaturated carbon atoms which occur in fatty acids having two or more double bonds and (2) the amount of natural antioxidant, specifically alpha tocopherol, stored in the fat. 

Compounds found in nature that have vitamin E activity, but which are less potent than alpha-tocopherol. 

Free radical scavenging activities of different phenolic acids, caffeic acid (CA), ferulic acid (FA) and p-coumaric acid (p CA) and natural antioxidants alpha tocopherol (alpha-toco) and BHA a synthetic antioxidant were compared with sinapic acid (SA). As indicated in Figure 15.10 under the tested conditions, the radical scavenging activity of the phenolic acids in the DPPH system decreased in the following order ... 

Laermer SF, Zambetti PF. Alpha-Tocopherol (vitamin E)—the natural antioxidant for polyolefins. J Plast Film Sheeting 1992 8(3) 228-48. 

Ouahchi K, Arita M, Kayden H, Hentati F, Ben Hamida M, Sokol R, Aral H, Inoue K, Mandel JL, and Koenig M (1995) Ataxia with isolated vitamin E deficiency is caused by mutations in the alpha-tocopherol transfer protein. Nature Genetics 9 141-145. 

Most interesting investigations in this field include different approaches to the biorefinery concept involving cottonseed. To serve as an example, Zhu et al. proposed the production of biodiesel, sterols, gossypol, and raffinose and nontoxic cottonseed meal in an integrated biorefinery, by a two-phase extraction process, using supercritical methanol (Zhu et al., 2014). Simultaneous production of alpha-tocopherol (a natural antioxidant) and FAME was also presented as a viable biorefinery concept (Zhu et al., 2012). 

The tocopherols were identified as naturally occurring oily substances and the first three were characterized as alpha, beta, and gamma forms, the biological activity of which decreased in that order. 

Alpha-d-tocopherol can also he readily synthesized in the laboratory. In the course of the synthesizing process, however, alpha-d-tocopherol is produced together with alpha-l-toco-pherol, its mirror-image molecule. The latter is not found in nature, and it has less biological activity than the so-called d-isomer. To get aroimd this confusing business, we rate vitamin E supplements in terms of international units (lu) of activity. In other words, the composition of the synthetic and the natural versions may not be identical, but a two himdred lu tablet will have the same level of activity, regardless of its origin. 

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