DL-a—Tocopherol

P-Apo-8 -carotenal is sold as a dry powder, as 1—1.5% vegetable oil solutions, as 20% suspensions ia vegetable oil, as 2—4% solutioas ia a mixture of moaoglycerides and DL-a-tocopherol, and as 10% dry beadlets. The vegetable-oil suspensions are purpHsh black fluids at room temperatures that set to... 

No unequivocal unique function for vitamin E has been defined. However, it does act as a hpid-soluble antioxidant in cell membranes, where many of its functions can be provided by synthetic antioxidants. Vitamin E is the generic descriptor for two famihes of compounds, the tocopherols and the tocotrienols (Figure 45—5). The different vitamers (compounds having similar vitamin activity) have different biologic potencies the most active is D-a-tocopherol, and it is usual to express vitamin E intake in milhgrams of D-a-tocoph-erol equivalents. Synthetic DL-a-tocopherol does not have the same biologic potency as the namrally occurring compound. 

Antioxidant activity was also tested in a liver microsome system. In this study, mice were treated by oral intubation (2 times/wk) with 0.2 ml olive oil alone or containing CLA (0.1 ml), linoleic acid (0.1 ml), or dl-a-tocopherol (lOmg). Four weeks after the first treatment, liver microsomes were prepared and subsequently subjected to oxidative stress using a non-enzymatic iron-dependent lipid peroxidation system. Microsomal lipid peroxidation was measured as thiobarbituric acid-reactive substance (TBARS) production using malondialdehyde as the standard. It was found that pretreatment of mice with CLA or dl-a-tocopherol significantly decreased TBARS formation in mouse liver microsomes (p < 0.05) (Sword, J. T. and M. W. Pariza, University of Wisconsin, unpublished data). 

Active analogues and related compounds include dl-a-Tocopherol l-a-toccpherol esters (succinate, acetate, phosphate), and fi, (. c.-tocopherol-,. The principal physiological forms are D-a-tocopherol. tocopheronolactone, and their phosphate esters. 

Oral solution (Novartis) (2) Cremophor RH 40, propylene glycol, DL-a-tocopherol,... 

To address the question of whether the biological antioxidant would withstand the high melt processing temperatures, dl-a-tocopherol (synthetic vitamin E) was extruded at different concentrations in PE and PP under different processing temperatures ranging from 210 °C to 285 °C. Similar experi-... 

The synthetic form of vitamin E exists as a mixture of eight possible optical isomers. The use of the synthetic form of the vitamin (dl-a-tocopherol) in the polymer would be expected to yield oxidative transformation products with a complex mixture of stereoisomeric structures. This was investigated by examining the oxidation of dl-a-tocopherol in solution by a mild oxidant, using HPLC and spectroscopic analysis to isolate and characterise the iso-... 

Vitamin E is required for normal growth and reproduction. The most important natural source is a-tocopherol found in plant oils and seeds. The ester form (e.g. vitamin E acetate) can be synthesized and is used for feed supplementation. One international unit is defined as being equivalent to the activity of 1 mg DL-a-tocopherol acetate. The nutritional role of vitamin E is closely interrelated with that of selenium and is involved mainly in the protection of lipid membranes such as cell walls from oxidative damage. Although these signs are similar to those of selenium deficiency, it is not possible to substitute selenium completely for vitamin E. Both nutrients are required in the diet. 

Feeding rats diet enriched with procyanidins complexed (1 3 w/w) with soybean lecithin (2.4%) for 3 weeks increased the TAC of their blood plasma (by 40% in young and by 30% in aged rats) (FI). Wistar rats fed a high-caloric, high-fat diet (chow supplemented with lard) and a high-caloric, normal-fat diet had decreased blood plasma TAC (by 8.8% and 9.0%, respectively) (B5). Intensive tocopherol supplementation of rats (20 g/kg diet of DL-a-tocopherol hydrogen succinate)... 

The effective but volatile 2,6-di-ferf.butyl-4-methyIphenol (11) was replaced for most applications by various mononuclear (12), binuclear (13), trinuclear (14) and tet-ranuclear phenols (15, 16). Recently, synthetic DL-a-tocopherol (17) was introduced for effective melt stabilization of PO. This antioxidant may be listed among the stabilizers generally recognised as safe (GRAS). 

Wade et al. (1986) reported that BHA and BHT were effective in retarding oxidation of anhydrous milk fat but DL-a-tocopherol acted as a pro-oxidant. Natural antioxidants in betel and curry leaves have also been reported to retard oxidation of anhydrous milk fat (Sharma, 1981 Parmer and Sharma, 1986). Amr (1991) reported that turmeric and wheat grits were as effective as BHA and BHT in controlling oxidative rancidity in sheep s anhydrous milk fat for up to 4 months. However, rosemary, sage, rue and fennel exerted pro-oxidant effects. Quercetin and rutin are reported to be efficient antioxidants in butter (Eriksson, 1987). 

Ammonium Hydroxide DL-a-Tocopherol D-a-Tocopherol Concentrate Tocopherols Concentrate, Mixed D-a-Tocopheryl Acetate DL-a-Tocopheryl Acetate D-a-Tocopheryl Acetate Concentrate D-a-Tocopheryl Acid Succinate... 

Tocopherols are pale yellow, viscous, oily substances which are insoluble in water but soluble in fats and oils. a-Tocopherol and its acetate are made synthetically, the synthetic products being racemates and designated DL-a-tocopherol and similarly DL-a-tocopherol acetate. These are mixtures of the four racemates. 

Based on biologiccd assay in vitamin E-deficient rats, the vitcuners have widely varying biological activity. The original international unit (iu) of vitamin E potency was equated with the activity of 1 mg of (synthetic) DL-a-tocopherol acetate on this bcisis, pure D-a-tocopherol (i i i -o -tocopherol, the most potent vitamer) is 1.49 iu per mg. The precise mixture of stereoisomers in this original standcud is unknown, and the different stereoisomers have very different biological activities, so that different preparations may differ considerably. 

Propylene glycol DL-a-tocopherol Ethanol 11.9% Corn oil-mono-di-triglycerides Polyoxyl 40 hydrogenated castor oil (Cremophor RH 40)... 

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