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Tocopheryl Acetate (tocopheryl + acetate)
Selected AbstractsVoltammetric Determination of ,-Tocopheryl Acetate in Pharmaceutical Dosage FormsELECTROANALYSIS, Issue 11 2004Slawomir Michalkiewicz Abstract A simple and rapid voltammetric method has been developed for the quantitative determination of ,-tocopheryl acetate (,-TOAc) in pharmaceutical preparations. Studies with linear scan (LSV), square-wave (SQWV) and differential pulse voltammetry (DPV) were carried out using platinum microelectrodes. A well-defined, irreversible oxidation wave/peak was obtained at 1.30,V (vs. Ag/AgCl reference electrode.) The use of SQWV or DPV technique provides a precise determination of ,-tocopheryl acetate using the multiple standard addition method. The statistical parameters and the recovery study data clearly indicate good reproducibility and accuracy of the method. Accuracy of the results assessed by recovery trials was found within the 99.3% to 103.5%, and 99.1% to 101.4%, for SQWV and DPV, respectively. The quantification limits for the both voltammetric techniques were found to be 6×10,5,M (SQWV) and 7×10,5,M (DPV). Analysis of the authentic samples containing ,-TOAc showed no interference with common additives and excipients, such as unsaturated fatty acids (co-formulated as glycerine esters) and vitamin A (as retinol or ,-carotene). The method proposed does not require any pretreatment of the pharmaceutical dosage forms. A gas chromatography determination of ,-TOAc in real samples was also performed for comparison. [source] Influence of Dietary Supplementation with ,-Tocopheryl Acetate and Canthaxanthin on Cholesterol Oxidation in ,3 and ,6 Fatty Acid-enriched Spray-dried EggsJOURNAL OF FOOD SCIENCE, Issue 7 2002J. Galobart ABSTRACT: The effect of feeding laying hens linseed oil or sunflower oil, with and without ,-tocopheryl acetate and/or canthaxanthin, was evaluated on cholesterol oxidation in spray-dried whole egg at various storage periods. Storage of spray-dried eggs at room temperature in the dark resulted in an increase in cholesterol oxidation products from 18.1 ,g/g, after spray drying, to 39.3 ,g/g, at 12 mo of storage. No differences were found with either dietary oil or canthaxanthin supplementation. However, ,-tocopheryl acetate supplementation resulted in a lower formation of cholesterol oxidation products during storage. No synergistic effect between ,-tocopherol and canthaxanthin was detected. [source] Effects of vitamin E and selenium on performance, digestibility of nutrients, and carcass characteristics of Japanese quails reared under heat stress (34 °C)JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2001K. Sahin This study was conducted to determine the effects of vitamin E (dL-,-Tocopheryl acetate) and selenium (Se; Na2 -SeO3) on performance, digestibility of nutrients and carcass characteristics of Japanese quails reared under chronic heat stress (34 °C). A total of 120 10-day-old Japanese quails were randomly assigned to four treatment groups, three replicates of 10 birds each. The birds with a 2 × 2 factorial design received either two levels of vitamin E (125 and 250 mg/kg of diet) or two levels of Se (0.1 or 0.2 mg/kg of diet). A 250-mg vitamin E/kg of diet compared with that of 125 mg/kg of diet and higher dietary Se inclusions (0.1 vs. 0.2 mg/kg) resulted in a better performance (p=0.001). The interaction between vitamin E and Se for feed intake (p=0.03), final body weight change (p=0.03) and feed efficiency (p=0.001) was detected. Carcass yield increased with increasing both dietary vitamin E and Se (p=0.001). The interactions on carcass characteristics were all non-significant (p > 0.06). Digestibility of nutrients (DM, OM, CP and ether extract) was higher with higher dietary vitamin E (p=0.03), and DM digestibility was also higher with higher dietary Se (p=0.05). There were no interactions detected for digestibility of nutrients (p=0.28). From the results of the present study, it was concluded that a combination of 250 mg of vitamin E and 0.2 mg of Se provides the greatest performance in Japanese quails reared under heat stress and this combination can be considered as a protective management practice in Japanese quail diets, reducing the negative effects of heat stress. [source] Voltammetric Determination of ,-Tocopheryl Acetate in Pharmaceutical Dosage FormsELECTROANALYSIS, Issue 11 2004Slawomir Michalkiewicz Abstract A simple and rapid voltammetric method has been developed for the quantitative determination of ,-tocopheryl acetate (,-TOAc) in pharmaceutical preparations. Studies with linear scan (LSV), square-wave (SQWV) and differential pulse voltammetry (DPV) were carried out using platinum microelectrodes. A well-defined, irreversible oxidation wave/peak was obtained at 1.30,V (vs. Ag/AgCl reference electrode.) The use of SQWV or DPV technique provides a precise determination of ,-tocopheryl acetate using the multiple standard addition method. The statistical parameters and the recovery study data clearly indicate good reproducibility and accuracy of the method. Accuracy of the results assessed by recovery trials was found within the 99.3% to 103.5%, and 99.1% to 101.4%, for SQWV and DPV, respectively. The quantification limits for the both voltammetric techniques were found to be 6×10,5,M (SQWV) and 7×10,5,M (DPV). Analysis of the authentic samples containing ,-TOAc showed no interference with common additives and excipients, such as unsaturated fatty acids (co-formulated as glycerine esters) and vitamin A (as retinol or ,-carotene). The method proposed does not require any pretreatment of the pharmaceutical dosage forms. A gas chromatography determination of ,-TOAc in real samples was also performed for comparison. [source] Oral vitamin E supplementation on oxidative stress, vitamin and antioxidant status in intensely exercised horsesEQUINE VETERINARY JOURNAL, Issue S36 2006C. A. WILLIAMS Summary Reasons for performing study: Vitamin E is the most commonly supplemented antioxidant in horses; however, previous research is not conclusive as to the recommended level for exercising horses. Objective: To evaluate the effects of 3 levels of vitamin E supplementation on oxidative stress and vitamin/antioxidant status in intensely exercised horses to determine the optimal level of vitamin E supplementation. Methods: Twelve unfit Standardbreds were divided into 3 groups, supplemented orally with 0 (CON), 5000 (MOD), or 10,000 (HI) iu/day of DL-,-tocopheryl acetate. The 3 times 3 Latin square design consisted of three 4 week supplementation periods with 4 week wash out periods between. After each period, horses underwent a treadmill interval exercise test. Blood samples were collected and heart rate (HR) measured before, during and after exercise. Data were analysed using ANOVA with repeated measures in SAS. Results: The CON group had lower HR throughout the test compared to the MOD and HI groups (P<0.05). There was an increase in plasma retinol (RET), ,-carotene (BC), red blood cell total glutathione and glutathione peroxidase with exercise (P<0.05), but all groups returned to baseline after 24 h. Plasma ,-tocopherol (TOC) increased from baseline with exercise (P<0.0001) in all groups; treatment differences were observed at 24 h (P<0.05). The HI and CON groups had lower BC compared to the MOD group (P = 0.05). Conclusions: Horses supplemented with vitamin E, at nearly 10-times the 1989 NRC recommended level, did not experience lower oxidative stress compared to control horses. Additionally, lower plasma BC levels observed in the HI group, which may indicate that vitamin E has an inhibitory effect on BC metabolism. Potential relevance: Supplementation above control levels is not more beneficial to oxidative stress and antioxidant status in intensely exercising horses; indeed, levels 10 times in excess may be detrimental to BC and should be avoided. [source] 3-Tocopherylisoxazolines by [2+3] CycloadditionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2004Thomas Rosenau Abstract New isoxazoline derivatives of ,-tocopherol (1), the main component of vitamin E, were synthesized in a facile, two-step sequence consisting of nitration followed by 1,3-dipolar cycloaddition. 5-Nitromethyl-,-tocopheryl acetate (3), obtained from the cheap ,-tocopheryl acetate (2) by direct nitration in one step, acted as the nitrile oxide precursor in the reaction with various alkenes. The facile conversion proceeded in the presence of equimolar amounts of PhNCO and catalytic amounts of triethylamine. The NMR spectra of the product isoxazolines 5,13, showing strongly temperature-dependent resonances of the 4,,-CH, 4-CH2 and the acetyl group, are discussed, and the crystal structures of model compounds containing a methyl group instead of the isoprenoid side chain are presented. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Dietary supplementation of ,-tocopheryl acetate on ,-tocopherol levels in duck tissues and its influence on meat storage stabilityINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2004Elizabeth Anne Russell Summary The effect of feeding three levels of ,-tocopheryl acetate on quality and stability of duck meat was studied. Day-old white Peking ducklings (n = 75) were assigned to three dietary treatments (n = 25) 20 mg , -tocopheryl acetate per kg feed (E20, control), 400 mg , -tocopheryl acetate per kg feed (E400) and 1000 mg , -tocopheryl acetate per kg feed (E1000). , -Tocopherol concentrations in breast, thigh, liver and heart tissues were significantly (P < 0.05) increased, in a dose-dependent manner. Supplementation also enhanced oxidative stability of duck muscle. Breast muscle was more susceptible to lipid oxidation than thigh muscle for all groups studied, even though breast muscle contained higher , -tocopherol levels than thigh muscle. These findings are significant because previous studies using chickens and turkeys showed that breast meat was always more stable than thigh meat and that thigh meat always had higher , -tocopherol levels than breast meat. Supplementation with , -tocopheryl acetate did not improve the colour stability of duck meat. [source] SELECT shows no effect on prostate cancer preventionINTERNATIONAL JOURNAL OF UROLOGICAL NURSING, Issue 1 2009Lawrence Drudge-Coates Abstract To determine whether selenium, vitamin E, or both could prevent prostate cancer and other diseases with little or no toxicity in relatively healthy men. Oral selenium (200 ,g/d from L -selenomethionine) and matched vitamin E placebo, vitamin E (400 IU/d of all rac-, -tocopheryl acetate) and matched selenium placebo, selenium + vitamin E, or placebo + placebo for a planned follow-up of minimum of 7 years and a maximum of 12 years. Number of men diagnosed with prostate cancer and prespecified secondary outcomes, including lung, colorectal, and overall primary cancer. Selenium or vitamin E, alone or in combination at the doses and formulations used, did not prevent prostate cancer in this population of relatively healthy men. [source] Effect of dietary copper and vitamin E supplementation, and extensive feeding with acorn and grass on longissimus muscle composition and susceptibility to oxidation in Iberian pigsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2001A. I. Rey The objective of this study was to assess the effect of dietary copper and/or vitamin E supplementation on composition and oxidation of M. longissimus in Iberian pigs and to compare it with meat samples from pigs produced extensively and fed with acorn and grass. Grass had the highest ,-tocopherol content (> 150 mg/kg DM), while acorns had the highest copper concentration (78.1 mg/kg DM). Dietary treatment did not affect copper composition in muscle and no interactions were detected between copper and ,-tocopherol. The ,-tocopherol content in muscle from pigs fed diets supplemented with ,-tocopheryl acetate (100 mg/kg feed) was 1.5 times greater (p < 0.0001) than those from pigs receiving a basel diet. M. longisssimus dorsi from pigs fed extensively had a higher concentration of ,-tocopherol than those fed in confinement with the basel level of ,-tocopheryl acetate, but lower values than pigs fed supplemented levels. Total n -3 fatty acids (p < 0.02) and hematin (p < 0.0001) concentrations were significantly higher in muscle from pigs fed extensively than when fed in confinement. Muscle homogenates from Iberian pigs fed in extensive conditions showed significantly (p < 0.02) higher susceptibility to oxidation than those from pigs fed mixed diets. Dietary ,-tocopheryl acetate supplementation (100 mg/kg feed) significantly (p < 0.05) reduced lipid oxidation of muscle, while dietary copper concentration did not modify susceptibility to lipid oxidation. Das Ziel dieses Studiums war die Wirkung von Kupfer und Vitamin E Ergänzung im Futter auf die Zusammenstellung und Oxydation von M. longissimus in Iberischen Schweinen zu erforschen und es mit Fleisch-Beispielen von freilaufenden Schweinen zu vergleichen, die mit Eicheln und Gras gefüttert wurden. Gras hatte den höchsten ,-Tocopherolgehalt (> 150 mg/kg), während Eicheln die höchste Kupferkonzentration hatten (78.1 mg/kg). Diätgemäße Behandlung von Kupfer beeinflußte keine kupferne Zusammenstellung im Muskel. Es wurden auch keine Wechselwirkungen zwischen Kupfer und ,-Tocopherol entdeckt. Der ,-Tocopherolgehalt im Muskel von Schweinen, gefüttert mit ,-Tocopherolacetat-Ergänzung (100 mg/kg füttern), war bedeutend größer (p < 0.0001) als jener von Schweinen, die eine fundamentale Nahrung bekamen. Der M. longisssimus dorsi von in Freilauf ernährten Schweinen hatte eine höhere ,-Tocopherol-Konzentration, als der von Schweinen, die mit einem fundamentalen Gehalt an ,-Tocopherolacetat gefüttert wurden (p < 0.0001), aber geringer als der von mit ,-Tocopherol-Ergänzung gefütterten Schweine. Der Gehalt von n -3 Fettsäuren (p < 0.02) und Hematin (p < 0.0001) war beträchtlich höher im Muskel von im Freilauf gefütterten Schweinen, als der von mit konzentrierter Nahrung gefütterten Schweinen. Muskel-Homogenate von freilaufenden Iberischen Schweinen zeigten bedeutend (p < 0.02) höhere Anfälligkeit zu Oxydation, als jene von Schweinen, die mit gemischter Nahrungen gefüttert wurden. Diätgemäße ,-Tocopherolazetat-Ergänzung (100 mg/kg füttern) zeigte bedeutend (p < 0.05) reduzierte lipoide Oxydation des Muskels, während diätgemäße kupferne Konzentration die Anfälligkeit zu lipoider Oxydation nicht modifizierte. [source] Effect of dietary linoleic acid concentration and vitamin E supplementation on cell desquamation and susceptibility to oxidative damage of pig jejunal mucosaJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2001C. J. López Bote Sixty Large White × Great York pigs weighing approximately 60 kg were individually fed on six experimental diets. The experiment was organized in a 3 × 2 factorial arrangement design with three different fat sources and a basal or supplemented (200 mg/kg diet) level of ,-tocopheryl acetate. All diets contained the same concentration of saturated fatty acids (15 ± 0.2 g/kg dry matter) but differed in the concentration of C18 : 2 (14 ± 0.5, 18 ± 0.4 and 21 ± 0.6 g/kg) and monounsaturated fatty acids (19 ± 0.2, 15 ± 1.2 and 10 ± 1.3 g/kg). No effect of dietary treatment was observed on weight gain and feed consumption. A histological study of the jejunal mucosa showed lower cell desquamation in groups containing a supplemental level of ,-tocopheryl acetate (p=0.080). A higher cell desquamation was found in the groups fed diets containing the higher concentration of C18 : 2 (p=0.087). We also observed an interaction effect (p < 0.001) of dietary fat source and vitamin E supplementation on jejunal cell desquamation in which the effect of dietary vitamin E was lower when diets with a low concentration of C18 : 2 were administered. In vitro- induced oxidation of jejunal mucosa homogenates was lower in pigs fed diets supplemented with ,-tocopheryl acetate (p < 0.002). The dietary concentration of C18 : 2 significantly affected oxidation of pig jejunal mucosa (p < 0.002). [source] Effects of lipid nanocarriers on the performance of topical vehicles in vivoJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2009Mojgan Moddaresi PharmD Summary Background/aims, Nanocarrier systems have been extensively studied for their suitability in personal care formulations. Theoretically, they could enhance skin delivery of active compounds, thereby improving in vivo efficacy of the products. As such the aim of this study was to evaluate the effect of a lipid nanocarrier (LNC) system loaded with tocopheryl acetate (TA) on the hydration, biomechanical properties, and antioxidant capacity of human skin, when used in two different vehicles, and compare it with a non-LNC formulation. Methods, TA-loaded lipid nanocarriers (TA-LNCs) were produced by the phase inversion method, using physiological lipids and purified by ultra-centrifugation. They were incorporated into a hydrophilic gel and foam, and their performance compared with a saturated TA solution in silicon oil. Skin hydration and biomechanical properties were measured by means of a corneometer and a cutometer, respectively, while a high-resolution spectrophotometer was used to assess skin redness after stimulation by methyl nicotinate in a micro-inflammatory test. Both short-term (3 h) and long-term trials (4 weeks) were performed. Results, The results confirmed that the LNCs enhanced skin hydration in both studies, while skin viscoelastic parameters remained practically unchanged during the 4-week study. The antioxidant assessment failed to show significant difference between the test sites. Conclusions, TA-loaded LNCs exhibited the ability to enhance skin hydration, while their effect on skin biomechanical properties and on antioxidant efficacy could not be statistically proved. [source] Influence of Dietary Supplementation with ,-Tocopheryl Acetate and Canthaxanthin on Cholesterol Oxidation in ,3 and ,6 Fatty Acid-enriched Spray-dried EggsJOURNAL OF FOOD SCIENCE, Issue 7 2002J. Galobart ABSTRACT: The effect of feeding laying hens linseed oil or sunflower oil, with and without ,-tocopheryl acetate and/or canthaxanthin, was evaluated on cholesterol oxidation in spray-dried whole egg at various storage periods. Storage of spray-dried eggs at room temperature in the dark resulted in an increase in cholesterol oxidation products from 18.1 ,g/g, after spray drying, to 39.3 ,g/g, at 12 mo of storage. No differences were found with either dietary oil or canthaxanthin supplementation. However, ,-tocopheryl acetate supplementation resulted in a lower formation of cholesterol oxidation products during storage. No synergistic effect between ,-tocopherol and canthaxanthin was detected. [source] Tocopheryl acetate disposition in porcine and human skin when administered using lipid nanocarriersJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2010Mojgan Moddaresi Abstract Objectives Assessing the delivery of a drug into the skin when it has been formulated within a nanocarrier is a complex process that does not conform to the conventions of traditional semi-solid formulations. The aim of this study was to gain a fundamental understanding of drug disposition in both human and porcine skin when applied using a lipidic nanocarrier. Methods A model system was generated by loading tocopheryl acetate into a well-characterised solid lipid nanoparticle and formulating this system as a traditional aqueous hyaluronic acid gel. Franz diffusion cells fitted with a silicone or nylon membrane were used to assess drug and particle transport independently whilst human and pig skin were employed to determine skin delivery. Key findings The tocopheryl acetate, when loaded into the solid lipid nanoparticles, did not release from the particle. However, 1.65 ± 0.90% of an infinite dose of tocopheryl acetate penetrated into the stratum corneum of pig skin when delivered using a nanoparticle-containing gel. Conclusions These results suggest that hydration of the stratum corneum in pig skin could lead to the opening of hydrophilic pores big enough for 50 nm-sized particles to pass into the superficial layers of the skin, a phenomenon that was not repeated in human skin. [source] A critical review of methodologies used in determination of relative bio-availability ratio of RRR -,-tocopheryl acetate and all - rac -,-tocopheryl acetateJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2010Yueming Dersjant-Li Abstract Bio-availability of different ,-tocopherol forms in livestock animals is measured by the increase in plasma or tissue concentrations of ,-tocopherol after oral administration. It is generally accepted that RRR -,-tocopheryl acetate (natural source vitamin E derived from vegetable oil) has a higher bio-availability compared to all - rac -,-tocopheryl acetate (synthetic vitamin E, i.e. ,-tocopherol produced by chemical synthesis). However, different bio-availability ratios have been reported in the literature. The major reason for conflicting results in literature studies was the inability to separate the proportion of ,-tocopherol originating from test materials, from the proportion of ,-tocopherol originating from basal dietary ingredients and pre-feeding. This causes significant variability. For bio-availability determination, a baseline or control treatment is essential. The estimation of bio-availability without correction for basal vitamin E status will lead to incorrect interpretation of the results. When using proper methodologies, it is possible to correct for the impact of ,-tocopherol intake from basal ingredients and ,-tocopherol originating from pre-feeding, therefore yielding results reflecting the true relative bio-availability of different ,-tocopherol substances. When reviewing literature data a critical evaluation of the method used in determination of relative bio-availability is recommended. Copyright © 2010 Society of Chemical Industry [source] In Vitro Antioxidant and In Vivo Photoprotective Effects of an Association of Bioflavonoids with Liposoluble VitaminsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2006Patrícia M. B. G. Maia Campos ABSTRACT A new tendency in cosmetic formulations is the association of botanical extracts and vitamins to improve skin conditions by synergic effects. The objective of this study was to determine the antioxidant activity of associated bioflavonoids, retinyl palmitate (RP), tocopheryl acetate (TA) and ascorbyl tetra-isopalmitate (ATIP), as well as their photoprotective effects in preventing increased erythema, transepidermal water loss (TEWL) and sunburn cell formation in hairless mouse skin. The antioxidant activity of solutions containing the association or each substance separately was evaluated in vitro by a chemiluminescence assay. The photoprotective effect was evaluated by means of in vivo tests. Dorsal skin of hairless mice was treated daily by topical applications for 5 days with formulations containing or not containing (vehicle) the flavonoid-vitamins association (5%). The skin was irradiated (UVA/B) 15 minutes after the last application. The results showed that bioflavonoids had in vitro antioxidant properties and also that when they were associated with vitamins their antioxidant activity was more pronounced. On the other hand, erythema and UV damage to the permeability barrier function (TEWL) was not significantly reduced by previous treatment with the flavonoid-vitamin-association formulations, when compared to the irradiated vehicle-treated area. However, the treatment protected the skin from UV damage because it reduced the number of sunburn cells, when compared to the vehicle-treated area. Finally, the association of vitamins and bioflavonoids added to a dermocosmetic formulation showed a relevant biological activity in terms of photoprotection, because the association of bioflavonoids and vitamins acted by different mechanisms, such as antioxidation and absorption of UV radiation, which suggests its use in antiaging and photoprotective products. [source] Dietary vitamin E requirement of the red drum Sciaenops ocellatusAQUACULTURE NUTRITION, Issue 3 2009L.I. PENG Abstract A 12-week feeding trial was conducted to establish the minimum dietary vitamin E requirement of juvenile red drum by broken-line regression analysis. The semi-purified basal diet was supplemented with 10, 20, 30, 40, 60 or 80 IU vitamin E kg,1 as all-rac -,-tocopheryl acetate. Juvenile red drum were conditioned by feeding the basal diet for 8 weeks prior to the feeding trial to reduce whole-body vitamin E levels. Then, fish initially averaging 12.2 ± 0.4 g fish,1 (mean ± SD) were fed the experimental diets at a rate approaching apparent satiation for 12 weeks. Weight gain and feed efficiency responses of fish fed diets were significantly (P < 0.01) altered by the level of vitamin E supplementation but not strictly in a dose-dependent manner. Vitamin E concentrations in liver and plasma also were significantly (P < 0.001) influenced by dietary vitamin E level. Plasma ascorbic acid in fish fed the basal diet tended (P = 0.066) to be lower than in fish fed diets containing the various levels of vitamin E. In addition, fish fed the basal diet showed edema in the heart, while fish fed all other diets were normal. Fish fed 60 or 80 IU all-rac -,-tocopheryl acetate kg,1 diet had significantly higher respiratory burst of head kidney macrophages than fish fed all other diets, although dietary effects on hematocrit and neutrophil oxidative radical production were not significant. The minimum dietary vitamin E requirement of juvenile red drum was established based on broken-line regression of liver thiobarbituric acid reactive substances to be 31 mg all-rac -,-tocopheryl acetate kg,1 diet. [source] Distribution of ,-tocopherol in fillets of turbot (Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus), following dietary ,-tocopheryl acetate supplementationAQUACULTURE NUTRITION, Issue 2 2004N. Ruff Abstract The present study investigated the distribution of , -tocopherol (vitamin E) in fillets of turbot (Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus). Turbot and Atlantic halibut were fed commercial diets, supplemented with different levels of , -tocopheryl acetate at the dietary target levels of 100, 500 and 1000 mg , -tocopheryl acetate kg,1 diet. The actual levels were 72, 547 and 969 for turbot, while halibut received 189, 613 and 875 mg , -tocopheryl acetate kg,1 diet. Turbot were fed the diets for 24 weeks, while Atlantic halibut were fed for 20 weeks prior to slaughter. At the end of the feeding periods fish had reached a final weight of around 1 kg. Fish were slaughtered and filleted. From the four fillets obtained per fish, 22 samples were taken from designated areas and analysed for their , -tocopherol content. The average concentrations of , -tocopherol incorporated in turbot and Atlantic halibut increased with increasing levels of , -tocopheryl acetate in the diet. Atlantic halibut had significantly (P < 0.05) more , -tocopherol in positions 2/II and 1/I than in position 9/IX. Turbot had significantly (P < 0.05) more , -tocopherol in position 2/II than in positions 1/I, 4/IV and 11/XI. By mapping , -tocopherol concentrations in fish fillets, a high degree of quality prediction may be established. Moreover, this study may help scientists in their choice of sampling position, when investigating if , -tocopheryl acetate supplementation resulted in successful , -tocopherol incorporation. [source] Simple and rapid high-performance liquid chromatographic method for endogenous , -tocopherol determination in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 8 2006Katthaleeya Nirungsan Abstract A simple and rapid reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of endogenous , -tocopherol in human plasma. Following addition of , -tocopheryl acetate as the internal standard, the plasma was deproteinized using acetonitrile and isopropanol mixture prior to HPLC analysis. Methanol was used as the mobile phase and the effluent was quantitated at 292 nm. By this developed method, the concentrations of , -tocopherol were linearly related to their responses in the range of 0.8,30 µg/mL. The relative standard deviations intra-day and inter-day for , -tocopherol in plasma were less than 10%. The percentage of bias was within ±4%, which confirmed the accuracy of the method. The method has been successfully applied for determining endogenous , -tocopherol in healthy Thai male volunteers. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||