Biodiscrimination of the Eight α-Tocopherol Stereoisomers Results in Preferential Accumulation of the Four 2R Forms in Tissues and Plasma of Rats

Weiser, H.; Riss, Georges; Kormann, Alfred W.

doi:10.1093/jn/126.10.2539

Cited by 77 publications

(63 citation statements)

References 22 publications

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“…Their relative bioavailability varies with time after dosing in humans and animals because all-rac-and RRR-␣-tocopherols are comparably absorbed [2] but differ in the extent of retention [21][22][23][24][31][32][33]. As a result of comparable absorption, the relative bioavailability of labeled all-rac-and RRR-␣-tocopherols is about 1:1 for the first 6 -12 hours after dosing [2].…”

Section: Variable Relative Bioavailability Of All-rac-and Rrr-␣-tocopmentioning

confidence: 99%

“…As a result of comparable absorption, the relative bioavailability of labeled all-rac-and RRR-␣-tocopherols is about 1:1 for the first 6 -12 hours after dosing [2]. However, as a result of preferential retention of 2R stereoisomers and elimination of 2S stereoisomers [31][32][33], the ratio of retained RRR-␣-tocopherol to retained all-rac-␣-tocopherol increases with time after single doses and eventually approximates 2:1 [21][22][23][24].…”

Section: Variable Relative Bioavailability Of All-rac-and Rrr-␣-tocopmentioning

confidence: 99%

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Re-evaluation of the relative potency of synthetic and natural α-tocopherol: experimental and clinical observations

Blatt

Pryor

Mata

et al. 2004

The Journal of Nutritional Biochemistry

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Section: Variable Relative Bioavailability Of All-rac-and Rrr-␣-tocopmentioning

confidence: 99%

Section: Variable Relative Bioavailability Of All-rac-and Rrr-␣-tocopmentioning

confidence: 99%

Re-evaluation of the relative potency of synthetic and natural α-tocopherol: experimental and clinical observations

Blatt

Pryor

Mata

et al. 2004

The Journal of Nutritional Biochemistry

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“…The discrimination between isomers occurs in the liver, with preferential incorporation of the RRR form into very low density lipoproteins and excretion of the 2S isomers in particular (Burton and Traber, 1990). Assuming that the 2S isomers are 50% of the all-rac-a-tocopheryl acetate (Weiser et al, 1996), the proportion of 2R isomers in the diet of the S-60 lambs was 1.2 fold that in the feed of the C-60 lambs. If the stereoselectivity of the lamb liver is similar to that of the rat, a-tocopherol levels in the plasma, muscle, adipose tissue and liver of the S-60 lambs should be 3.2-, 2.0-, 1.9-and 1.4-fold higher than in the tissues of the C-60 lambs.…”

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confidence: 99%

Influence of vitamin E supplementation and basal diet on the vitamin E status, performance and tissue fatty acid concentration in lambs

Kasapidou

Enser

Wood

et al. 2009

Animal

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In order to determine the effect of dietary vitamin E level and basal diet on vitamin E status, performance and tissue fatty acid content, five groups of eight Suffolk 3 Charollais wether lambs with an initial live weight of 28.4 (s.d. 1.6) kg were allocated to one of five concentrate-based diets supplemented with all-rac-a-tocopheryl acetate to contain 30 mg (C-30), 60 mg (C-60), 120 mg (C-120), 250 mg (C-250) or 500 mg (C-500) a-tocopheryl acetate/kg dry matter (DM), for 63 days. Two additional groups of eight lambs entered the study at 31.2 (s.d. 3.3) kg and were fed grass silage and 400 g/day concentrate for 56 days, with the whole diet providing the equivalent of 60 mg (S-60) or 500 mg (S-500) a-tocopheryl acetate/kg DM. Lambs were weighed and blood samples obtained by venipuncture weekly. Dietary vitamin E level did not affect performance ( P . 0.05), but lambs fed grass silage grew more slowly ( P , 0.001) and had a higher ( P , 0.001) feed conversion ratio (kg feed/kg gain) than those fed concentrates. At day 0 plasma a-tocopherol concentrations were 0.8 mg/ml and did not differ between treatments ( P . 0.05). Plasma a-tocopherol concentrations then decreased in all lambs except for those fed S-500, which increased, and at slaughter were (mg/ml) 0.07, 0.23, 0.39, 0.76 and 1.57 in C-30, C-60, C-120, C-250 and C-500 and 1.18 and 1.93 in S-60 and S-500, respectively. At slaughter, muscle and liver a-tocopherol concentrations were in the deficiency range for lambs fed C-30, C-60 or C-120, whereas plasma creatine kinase and tissue polyunsaturated fatty acids were unaffected by dietary vitamin E level, but creatine kinase levels were higher ( P , 0.05) and glutathione peroxidise levels lower ( P , 0.001) in lambs fed grass silage than concentrates alone. Muscle and liver a-tocopherol concentrations were 1.8-and 4.1-fold higher in lambs fed S-60 than C-60, but there was less of a difference between lambs fed S-500 or C-500 with muscle and liver differences of 0.4-and 0.7-fold, respectively. Tissue n-3 polyunsaturated fatty acid concentrations were higher ( P , 0.05) and n-6 fatty acids lower in lambs receiving the grass silage compared to concentrate-based diets, but were not affected by dietary vitamin E level. It is concluded that lower plasma and tissue levels of a-tocopherol are present in lambs supplemented with all-rac-a-tocopheryl acetate on a concentrate compared to a mixed diet of silage and concentrates, and that normal growth can be achieved at tissue levels previously considered to represent deficiency.Keywords: a-tocopherol, concentrates, fatty acids, grass silage, lamb growth ImplicationsVitamin E is necessary to protect tissues from oxidative damage. When lambs were fed a concentrate or grass silage-based diet supplemented with increasing amounts of vitamin E, substantially lower plasma and tissue vitamin E levels were observed in lambs receiving the concentratebased diets. Animal performance was, however, unaffected by dietary vitamin E level. Tissue fatty acid composition was also unaffected by...

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“…Here we focused on the nutritional effect of the a-tocopherol for human health. That is, a-tocopherol possesses the highest vitamin E activity among the four different tocopherol forms (Weiser et al 1996;Eitenmiller 1997). It is also known that only a-tocopherol is retained and distributed throughout the body during digestion (Shintani and DellaPenna 1998).…”

Section: Discussionmentioning

confidence: 99%

Seed specific expression of perilla γ-tocopherol methyltransferase gene increases α-tocopherol content in transgenic perilla (Perilla frutescens)

Lee

Kim

et al. 2007

Plant Cell Tiss Organ Cult

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Increasing vitamin E activity in economically important oil crops such as perilla will enhance the nutritional value of these crops. Perilla (Perilla frutescens Britt) represents an important oil crop in Asian countries, including Korea. Using Agrobacterium-mediated transformation, we have engineered perilla with the c-tocopherol methyltransferase (c-TMT) gene under the control of seed-specific vicillin promoter. Molecular characterization including PCR, Southern and Northern blots confirmed that the c-TMT transgene was successfully inherited to and expressed in the progeny plants. The c -TMT transgene was specifically expressed in immature seeds of transgenic plants, leading to efficient conversion of c-tocopherol to a-tocopherol and dramatic increase in seed a-tocopherol content, as detected by high performance liquid chromatography analysis. We also showed that such a high a-tocopherol content phenotype was transmitted to the progeny plants. In addition, there was no significant change in fatty acid composition in transgenic seeds as compared with untransformed control Yeupsil cultivar, suggesting the lack of interplay between the fatty acid and tocopherol biosynthesis pathways. This was the first report on over expression of the c-TMT gene in transgenic perilla displaying desirable high a-tocopherol content phenotype. Since a-tocopherol has the highest vitamin E activity, the transgenic perilla with high a-tocopherol content in seeds developed in this study will benefit both human and animal health.

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Biodiscrimination of the Eight α-Tocopherol Stereoisomers Results in Preferential Accumulation of the Four 2R Forms in Tissues and Plasma of Rats

Cited by 77 publications

References 22 publications

Re-evaluation of the relative potency of synthetic and natural α-tocopherol: experimental and clinical observations

Re-evaluation of the relative potency of synthetic and natural α-tocopherol: experimental and clinical observations

Influence of vitamin E supplementation and basal diet on the vitamin E status, performance and tissue fatty acid concentration in lambs

Seed specific expression of perilla γ-tocopherol methyltransferase gene increases α-tocopherol content in transgenic perilla (Perilla frutescens)

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