Fractionation tocopherols

Common soy derivatives (Figure 8.2) are lecithin (raw, fractionated, phospha-tidylcholin fraction), tocopherols (vitamin E), soy isoflavones, soy flour, molasses, vegetable oil, and sterols. DNA can usually be found only in raw and some fractionated lecithins and soy flour as well as cmde soybean oil. 

On a semipreparative scale, SFC has shown its value for the isolation of tocopherols and tocotrienols from wheat germ oil, a process which may be of industrial interest (162,166). It consists of four steps, i.e., supercritical fluid extraction (SEE) of the oil, preconcentration, chromatography on a silica column with UV detection at 290 nm, and fractionation. Tocopherols were considerably enriched (up to 70% to 85% purity) in the collected fractions relative to the crude samples, in which they represented only minor constituents among an excess of triglycer-... 

Fluorimetric methods of analysis make use of the natural fluorescence of the analyte, the formation of a fluorescent derivative or the quenching of the fluorescence of a suitable compound by the analyte. Fluorescence cannot occur unless there is light absorption, so that all fluorescent molecules absorb, but the reverse is not true only a small fraction of all absorbing compounds exhibits fluorescence. The types of molecule most likely to show useful fluorescence are those with delocalised ji-orbital systems. Often, the more rigid the molecule the stronger the fluorescence intensity. Naturally fluorescent compounds include Vitamin A, E (tocopherol). 

Coffee oil is generally described as the petroleum ether-soluble fraction from green coffee beans. Arabica coffees contain 11.1 to 13.6% oil, whereas Robusta coffees contain only 4.4 to 4.8% oil.106 Triglycerides constitute 79% of this oil, terpene esters 17%, and the remaining 4% is contributed by sterols, free terpenes, tocopherols, and as yet unknown... 

Literature data on cytotoxic effects of photoexcited fullerene C60 are controversial. In the studies on transformed B-lymphocytes of Raji fine, phototoxic action of water-soluble carboxy-C60 was not revealed even upon its concentration of 5 x 10 5 M (Irie et al., 1996). In the study (Kamat et al., 2000) damaging effect of fullerenes C60 in dependence on intensity of irradiation toward CHO cells has been demonstrated. Using microsomal fraction of rat liver that was treated with C -cyclodextrin complex, it was shown that already in 5-30 min after UV-irradiation the accumulation of LPO products occurs that is suppressed by antioxidants like ascorbic acid and a-tocopherol. Similar effect of fullerenes C60 has been revealed in microsomal fraction of the cells of ascitic sarcoma 180 (Kamat et al., 2000). 

In contradistinction to the decrease in lysosomal enzyme activity observed in alveolar macrophages and bronchial lavage fluid, Dillard et al. reported that continuous ozone exposure (0.70-0.79 ppm for 5-7 days) resulted in an increase in the activity of some lysosomal hydrolases in rat whole-lung homogenates and lung fractions, including the soluble supernatant. The tocopherol concentrations of the diet had no effect on the findings. 

Lipids are important components of the diet fatty acids are the higher energetic source as they ensure 9kcal/g. Furthermore, some peculiar fatty acids themselves and several components of the unsaponifiable fraction are biologically active molecules, as they can act as vitamins (tocopherols— vitamin E), provitamins (carotenes—vitamin A, cholecalcipherol—vitamin D), vitamin-like (essential fatty acids), and hormones or hormone precursors (sterols—steroidal hormones). 

Xanthosoma violaceum, Araceae, widely distributed in Dominican Republic, Puerto Rico, Guatemala, and Equator, was investigated for in vitro antioxidant and free-radical scavenger activities. The fraction rich in C-glycosylflavones showed with l,l-diphenyl-2-picryl-hydrazyl radical (DPPH) test an EC50 of 11.6 pg/ml, compared with quercetin (2.3 pg/ml) and a-tocopherol (10.1 pg/ml). 

Brunner et al [1, 2] investigated separations of fatty acids according to chain length, using methyl esters of different carbon chain length from C14 to Cl8, separation of tocopherols from a by-product of the edible oil production and separation of fish oil esters [3], Stahl et al [4] proposed the supercritical fractionation of orange peel oil and Reverchon et al [5,6] of an orange flower concrete. Different authors treated citrus peel oil [7,8] and citrus oil [9-12]. 

Murphy, M.E. and Kehrer, J.P. 1987. Simultaneous measurment of tocopherols and tocopheryl quinines in tissue fractions using high-performance liquid chromatography with redox-cycling electrochemical detection../. Chromatogr. 421 71-82. 

Indyk and Woollard (195) demonstrated that the removal of cholesterol from the un-saponifiable fraction of vitamin D-supplemented whole milk powder by methanolic precipitation and filtration was an adequate cleanup procedure, making semipreparative HPLC unnecessary. This simplified procedure was made possible by connecting two analytical columns in series. The tandem columns adequately separated vitamins D2 and D3 from one another and from vitamins A and E. The analysis of infant formulas (100) required cleanup by silica solid-phase extraction to remove the minor tocopherols and tocotrienols, which constituted potential sources of interference. 

Fig. 15 HPLC of vitamins A, D3, and E in the unsaponifiable fraction of milk. Column, 5 /nm Spheri-5 RP-18 (220 X 4.6-mm ID) mobile phase, methanol/water (99 1) containing aqueous 0.1 M lithium perchlorate, 1 ml/min amperometric detection (oxidative mode), glassy carbon electrode, +1.05 V, vs silver-silver chloride reference electrode. Peaks (1) retinol (2) vitamin D3 (3) a-tocopherol. (Reprinted from Ref. 143 with the kind permission of Elsevier Science-NL, Sara Burgerhartstraat 25,1055 KV Amsterdam, The Netherlands.)...

Inhibitors like this are said to have a stoichiometric factor of 2 that is, 2 radicals are stopped per molecule of inhibitor.) We can calculate the fraction of the peroxyl radicals that undergo reaction 7 and continue the chain versus those that react with tocopherol, Equation 16, ultimately to terminate the autoxidation. In this calculation (Equation 18), the concentration of peroxyl radicals cancels out (21). We will use the concentration of tocopherol that we use in our micelle studies and the value of k.. that we measure for tocopherol (Sit). in... 

The method applied consists in a prior, basic hydrolysis (saponification) of the oil sample, followed by thin layer chromatography (TLC) fractionation of the classes of compounds, namely hydrocarbons, tocopherols, long-chain aliphatic alcohols, triterpenic alcohols, methyl sterols, sterols and triterpenic dialcohols. This procedure loses all information about the combination of polycyclic triter-penes with fatty acids. 

The unsaponifiable fraction of most plant oils is relatively small and includes both sterols and tocopherols. Nevertheless the presence of distinct components in this fraction could provide a useful fingerprint for determining the authenticity or purity of these oils. 

Barrefors et al. (1995) analyzed samples with and without oxidized flavor from two commercial herds. Their data indicated that oxidized milk samples had a higher linoleic acid content in the neutral fat fraction and contained a higher concentration of hexanal. At one of the farms, the concentration of both a-tocopherol and (3-carotene were lower in samples that developed off-flavor. They speculated that high-yielding cows fed high amounts of unsaturated fats in their feed needed higher dietary concentrations of a-tocopherol and (3-carotene. 

Lang, J.K., Gohil, K. and Packer, L. (1986) Simultaneous determination of tocopherols, ubiquinols, and ubiquinones in blood, plasma, tissue homogenates, and subcellular fractions, Anal. Biochem. 157, 106-116. 

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