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Titolo:
BIODISCRIMINATION OF THE 8 ALPHA-TOCOPHEROL STEREOISOMERS RESULTS IN PREFERENTIAL ACCUMULATION OF THE 4 2R FORMS IN TISSUES AND PLASMA OF RATS
Autore:
WEISER H; RISS G; KORMANN AW;
Indirizzi:
F HOFFMANN LA ROCHE & CO LTD,VITAMINS & FINE CHEM,RES & TECHNOL DEV CH-4002 BASEL SWITZERLAND F HOFFMANN LA ROCHE & CO LTD,VITAMINS & FINE CHEM,RES & TECHNOL DEV CH-4002 BASEL SWITZERLAND
Titolo Testata:
The Journal of nutrition
fascicolo: 10, volume: 126, anno: 1996,
pagine: 2539 - 2549
SICI:
0022-3166(1996)126:10<2539:BOT8AS>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
PERFORMANCE LIQUID-CHROMATOGRAPHY; VITAMIN-E; RESORPTION-GESTATION; 8 STEREOISOMERS; BIOLOGICAL SPECIMENS; GAS-CHROMATOGRAPHY; ACETATE; LIVER; DISCRIMINATION; BIOPOTENCIES;
Keywords:
VITAMIN-E; ALL-RAC-ALPHA-TOCOPHEROL ACETATE; ALPHA-TOCOPHEROL STEREOISOMERS; BIODISCRIMINATION; ACTIVITY RATIO (BIOPOTENCY); RATS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
H. Weiser et al., "BIODISCRIMINATION OF THE 8 ALPHA-TOCOPHEROL STEREOISOMERS RESULTS IN PREFERENTIAL ACCUMULATION OF THE 4 2R FORMS IN TISSUES AND PLASMA OF RATS", The Journal of nutrition, 126(10), 1996, pp. 2539-2549

Abstract

According to the USP, 2R,4'R,8'R-alpha-tocopheryl acetate (RRR-alpha-TAc) is 1.36 times more active than all-rac-alpha-tocopheryl acetate (all-rac-alpha-TAc). The all-rac form contains 12.5% each of the stereoisomers RRR, RRS, RSR, RSS, SSS, SSR, SRS and SRR, which display different biopotencies. In the present study, female rats fed a vitamin E-deficient diet were administered 0.82 mg of ali-rac-alpha-TAc or 0.60 mg of RRR-alpha-TAc daily for up to 90 d. alpha-Tocopherol concentrations in liver, brain, adipose tissue and plasma were not significantly different among groups on treatment d 64 and 90. Thus, equipotent dosages of all-rac-alpha-TAc or RRR-alpha-TAc resulted in equimolar alpha-tocopherol plasma and tissue concentrations. A comparison with rats administered tocopherol-free placebo showed that plasma and tissue cu-tocopherol of alpha-TAc-treated rats represented alpha-tocopherol uptake during the repletion period. The eight individual alpha-tocopherol stereoisomers in tissues and plasma were determined by chiral HPLC and capillary gas chromatography. Rats treated with all-rac-alpha-TAc preferentially accumulated the four 2R alpha-tocopherol stereoisomers (15-22% each, sum of all 2R = 70-86%) in tissues and plasma. The remaining 14-30% were 25 stereoisomers with a predominance of the SRS form, In conclusion, all-rac-alpha-TAc administration led to the presence of all eight alpha-tocopherol stereoisomers in rat liver, brain, adipose tissue and plasma. The four 2R stereoisomers including RRR-alpha-tocopherol were equally and significantly enriched. This confirmed that the configuration at C-2 of the alpha-tocopherol molecule has a major impact on stereoisomer biodiscrimination. Furthermore, the results are in agreement with the hypothesis that for alpha-tocopherol stereoisomers, biopotency differences are related to corresponding differences of alpha-tocopherol concentrations.

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Documento generato il 30/03/20 alle ore 00:55:51