All-rac-a-tocopheryl acetate

The acetate ester of a-tocopherol, rather than the free alcohol, is used as a food supplement on account of its greater stability. Both 7 7 f -a-tocopheryl acetate and totally synthetic all-rac-a-tocopheryl acetate are commercially available, the former having a biological activity of 1.36 IU/mg and the latter 1.00 IU/mg (44). The / / / -a-tocopheryl acetate is obtained by extraction from vegetable oils. Since it is not isolated without some chemical processing, it cannot legally be called natural, but it can be described as derived from natural sources. 

In the analysis of foods that contain significant amounts of both naturally occurring toco-pherols and supplemental a-tocopheryl acetate, saponification, by hydrolyzing the esterified vitamin E, allows the total a-tocopherol content to be measured as a single peak by HPLC. It should be noted that if totally synthetic all-rac-a-tocopheryl acetate is the supplemental form used, its hydrolysis product, all-rac-a-tocopherol, is less biologically active than is naturally occurring RRR-a-tocopherol, making it impossible to calculate a potency value for the total vitamin E. This problem does not arise if the supplement used is / / / -a-tocopheryl acetate. 

Fumed silica A-200 (Pilot plant at the Institute of Surface Chemistry, Kalush, Ukraine specific surface area Ascorbic acid (vitamin C) and all-rac-a-Tocopheryl acetate (vitamin E acetate) were used as adsorbates. Folin-Ciocalteu s phenol reagent (Merck) was used to measure the total polyphenolic index. Silica samples with different degree of surface silylation were obtained using gas-phase chemical modification of highly disperse silica (A-200) surface by trimethylchlorosilane.6... 

All-rac-a-Tocopheryl Acetate occurs as a colorless to yellow or green-yellow, clear, viscous oil. It is a form of vitamin E. 

Labeling All label claims that are in terms of International Units (IU) should be based on the following 1 mg of all-rac-a-tocopheryl acetate = 1 IU. 

Assay Determine as directed in the monograph for RRR-a-Tocopheryl Acetate, using the following as the Assay Preparation. Dissolve an accurately weighed amount of sample, equivalent to about 30 mg of all-rac-a-tocopheryl acetate, in 10.0 mL of the Internal Standard Solution. 

Gum Arabic Ammonia Solution All-rac-a-Tocopherol RRR-a -T ocopherol RRR-Tocopherols Concentrate, Mixed RRR-a-Tocopheryl Acetate All-rac-a-Tocopheryl Acetate RRR-a-Tocopheryl Acetate Concentrate RRR-a-Tocopheryl Acid Succinate... 

GW Chase Jr, RR Eitenmiller, AR Long. Liquid chromatographic analysis of all-rac-a-tocopheryl acetate, tocopherols, and retinyl pahnitate in SRM 1846. J Liq Chromatogr Rel Technol 20 3317-3327, 1997. 

RV Acuff, SS Thedford, NN Hidiroglou, AM Papas, TA Odom Jr. Relative bioavailability of RRR- and all-rac-a-tocopheryl acetate in humans studies using deu-terated compounds. Am J Clin Nutr 60, 397-402, 1994. 

Edible vegetable oils regularly contain varying amounts of toco-pherols (vitamin E) or, rarely, their esters. Synthetic all-rac-a-tocopheryl acetate (D,L-a-tocopheryl acetate) is often added to oils and other products as a food additive. The fat products often contain synthetic retinyl acetate (vitamin A), which is more stable than retinol. Emulsified fats sometimes contain vitamin D. Animal fats contain only small amounts of KpophOic vitamins, except for... 

The international unit of activity (lU) is defined as an activity of 1 mg of synthetic all-rac-a-tocopheryl acetate (D,i-a-tocopheryl acetate) that is often used for food fortification and in multivitamin tablets. The biological activity of tocopherols and tocotrienols and their stereoisomers is difficult to determine, and is expressed in a relatively wide range. (i RJ )-a-Tocopherol is generally considered the most effective substance, and its esters have similar effects. -Tocopherol has about 50% the activity of a-tocopherol, y-tocopherol about 10% and 5-tocopherol approximately 3% of the a-tocopherol activity. 

According to the US Pharmacopoeia (USP), IIU of vitamin E equals Img all rac a-tocopheryl acetate, 0.67mg RRR-a-tocopherol, or 0.74 mg RRR-a-toco-pheryl acetate. These conversions were estimated on the relative biologic activities of the various forms when tested in the rat assay for vitamin E deficiency, the fetal resorption assay. These USP lUs are currently used in labeling vitamin E supplements and food for-tificants. It should be noted that the current RDA does not use vitamin E USP units but rather the recommendation for adults is set at 15 mg of RRR-a-tocopherol or IR-a-tocopherols. Most foods contain RRR-a-tocopherol naturally, but foods that have been fortified with vitamin E contain the synthetic form, e.g., fortified breakfast cereals. If the amount of vitamin E on the label is given in international units, then this must be multiplied by the factors given in Table 2 to obtain the amount of 2R-/3-tocopherol. 

---