Tocotrienols chemistry

Kamal-Eldin, A. Appelqvist, L. A. The chemistry and antioxidant properties of tocopher-ols and tocotrienols. Lipids 1996, 31, 671-701. 

Vitamin E is an effective scavenger of lipid peroxy radicals and is efficient at protecting unsaturated fatty acids against lipid peroxidation. The chemistry of vitamin E is rather complex as there are eight compounds, four tocopherols and four tocotrienols, which exhibit vitamin E activity. The relative bioactivity of the various compounds varies considerably, from 1.0 for a-tocopherol to 0.03 for 8-tocopherol. In milk, a-tocopherol accounts for virtually all of vitamin E, although very small amounts of (3-tocopherols and y-tocopherols are present. Also, the concentration of a-tocopherol in milk fat varies widely, with the level in samples of commercial butter ranging from 18 to 35 pg/g fat (MAFF, 1999). These concentrations equate to a low level of vitamin E bioactivity, 0.025 to 0.05 IU/g fat. 

The carbons at locations 4 and 8 in the side chains of the tocopherols are asymmetric, as is the number 2 carbon in the chro-man ring. The resulting possible isomers are described as having R or S rotation. The natural tocopherols and tocotrienols are predominantly RRR isomers. Morton (1967) has summarized the chemistry of the tocopherols as shown in Figure 9-7. 

Parker RA, Pearce BC, Clark RW, Gordon DA, and Wright JJ (1993) Tocotrienols regulate cholesterol production in mammalian cells by post-transcriptional suppression of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Journal of Biological Chemistry 268, 11230-8. 

Determination of four tocopherols and four tocotrienols in vegetable oils and fats by the official American Oil Chemists Society method is based on separation by normal-phase HPLC and fluorescence detection (AOCS, 1990). Oil samples are dissolved in hexane, whereas margarines and other fats containing vitamer esters need a cold saponification step to liberate the vitamers. The American Association of Cereal Chemists has a method to analyze vitamin E in various foods. This method (AACC, 1997) is applicable to a vitamin E range of 1 x 10" - 100%, and it includes hot saponification and separation by reversed-phase HPLC. Results are calculated as a-tocopherol acetate. The Royal Society of Chemistry has approved a method to analyze vitamin E in animal feedstuffs by normal-phase HPLC after the vitamers have been liberated by hot saponification (Analytical Methods Committee, 1990). 

Kamal-Eldin, A. and Appelqvist, L.-A. 1996. The Chemistry and Antioxidant Properties of Tocopherols and Tocotrienols. Lipids. 31 671-701. 

Chemistry. The vitamin E family I )nsists of tocopherols and tocotrienols. There been considerable debate as to whether b RRR isomer is the only biologically active arm cf the vitamin. The vitamin of commerce a-tocopheroi, either as a racemic synthetic... 

A. Kamal-Eldin and L-A. Appelqvist The chemistry and antioxidant properties of tocopherols and tocotrienols. Lipids 31,671 (1996). 

The chapter concludes with a review of the chemistry of the tocopherols and tocotrienols, groups of lipids which have generated a vast amount of work... 

Baldenius, K., von dem Bussche-Hiinnfeld, L., HUgemann, E., et al. (1996). Vitamin E (Toco-pherols, Tocotrienols), in Ullmann s Encyclopedia of Industrial Chemistry, 5th edition, Vol. A27 Vitamins, Wiley-VCH, Weinheim, Chapt. 4, pp. 478-488. 

S Kasparek. Chemistry of tocopherols and tocotrienols. In LJ Machlin, ed. Vitamin E. A Comprehensive Treatise. New York Marcel Dekker, 1980, pp 7-65. 

Britz S.J., Prasad P.V.V., Moreau R.A., L. H. AUen, Jr., Kremer D.F., Boote K.J. Influence of growth temperature on the amounts of tocopherols, tocotrienols, and y-oryzanol in brown rice. Journal of Agricultural and Food Chemistry, 55 7559-7565 (2007). 

Cunha S.C., Amaral J.S., Fernandes J.O., Oliveira M.B. Quantification of tocopherols and tocotrienols in Portuguese olive oUs using HPLC with three different detection systems. Journal of Agricultural and Food Chemistry, 54 3351-3356 (2006). 

Qureshi A.A, Mo H., Packer L., Peterson D.M. Isolation and identification of novel tocotrienols from rice bran with hypocholesterolemic, antioxidant, and antitumor properties./oumo/ of Agricultural and Food Chemistry, 48 3130-3140 (2000). 

Chemistry—Eight tocopherols and tocotrienols with vita-... 

Szydlowski, J. (2002). Phase Behaviour of Room Temperature Ionic Liquid Solutions An Unusually Large Co-Solvent Effect in (Water Plus Ethanol). Physical Chemistry Chemical Physics, Vol. 4, No. 10, pp. 1701-1703, ISSN 1463-9076 Ng, M. H., Choo, Y. M., Ma, A. N., Cheng, H. C. Hashim, M. A. (2004). Separation of Vitamin E (Tocopherol, Tocotrienol, and Tocomonoenol) in Palm Oil. Eipids, Vol. 39, No. 10, pp. 1031-1035, ISSN 0024-4201... 

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