984 resultados para DELTA-TOCOPHEROL
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Microemulsion electrokinetic capillary chromatography has been successfully applied to the separation and determination of water-soluble vitamins (thiamine hydrochloride, riboflavin, niacin, pyridoxine hydrochloride, folic acid, cobalamin, ascorbic acid) and a fat-soluble vitamin (alpha-tocopherol acetate). The optimal microemulsion buffer contained sodium dodecylsulfate (SDS) as surfactant, butan-1-ol as the co-surfactant, ethyl acetate as the oil and pH 9.2 tetraborate buffer, modified with 15% (v/v) 2-propanol. UV detection at 214 nm gave adequate sensitivity without interference from sample excipients. Under the optimized conditions, the vitamins were baseline separated in less than 7 min. Analytical curves of peak area versus concentration presented coefficients of determination (R (2) ) > 0.99, acceptable limits of quantification between 8.40 and 16.23 mu g mL(-1) were obtained. Vitamin levels in liquid formulation were quantified with intra-day precision better than 0.99% RSD for migration time and 1.19% RSD for peak area ratio. Recoveries ranged between 98.7 and 101.7%. The method was considered appropriate for rapid and routine analysis.
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The antioxidant effects of beta-carotene, oil-soluble (bixin) and water-soluble (norbixin) annatto preparations and mixtures of these carotenoids with virgin olive oil polar extract were assessed in bulk olive oil and oil-in-water emulsions stored at 60degreesC. Norbixin was the only carotenoid that inhibited the oxidative deterioration of lipids in both systems. Though bixin and beta-carotene did not retard autoxidation, their mixtures with the polar extract from virgin olive oil enhanced the antioxidant effect of the olive oil extract. Norbixin (2 mM) was of similar activity to delta-tocopherol (0.1 mM) in stored oil. The combination of norbixin with ascorbic acid or ascorbyl palmitate in oil showed a reduction in formation of volatile oxidation products but not in peroxide value, compared with the analogous sample lacking norbixin. In olive oil-in-water emulsions, norbixin (2 mM) reduced hydroperoxide formation to a similar extent as delta-tocopherol (0.1 mM), which in turn was a better antioxidant than alpha-tocopherol. A synergistic effect between norbixin and ascorbic acid or ascorbyl palmitate was observed in the emulsion systems. (C) 2003 Elsevier Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The objective of this study was to investigate whether differences in diet and in single-nucleotide polymorphisms (SNPs) found in paraoxonase-1 (PON-1), 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), cholesterol ester transfer protein (CETP) and apolipoprotein E (APOE) genes, are associated with oxidative stress biomarkers and consequently with susceptibility of low-density cholesterol (LDL) to oxidation. A multivariate approach was applied to a group of 55 patients according to three biomarkers: plasma antioxidant activity, malondialdehyde and oxidized LDL (oxLDL) concentrations. Individuals classified in Cluster III showed the worst prognoses in terms of antioxidant activity and oxidative status. Individuals classified in Cluster I presented the lowest oxidative status, while individuals grouped in Cluster II presented the highest levels of antioxidant activity. No difference in nutrient intake was observed among the clusters. Significantly higher gamma- and delta-tocopherol concentrations were observed in those individuals with the highest levels of antioxidant activity. No single linear regression was statistically significant, suggesting that mutant alleles of the SNPs selected did not contribute to the differences observed in oxidative stress response. Although not statistically significant, the p value of the APO E coefficient for oxLDL response was 0.096, indicating that patients who carry the TT allele of the APO E gene tend to present lower plasma oxLDL concentrations. Therefore, the differences in oxidative stress levels observed in this study could not be attributed to diet or to the variant alleles of PON-1, CETP, HMGCR or APO E. This data supports the influence of gamma-tocopherol and delta-tocopherol on antioxidant activity, and highlights the need for further studies investigating APO E alleles and LDL oxidation.
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In skin, vitamin E acts as the predominant lipophilic antioxidant with a protective function against irradiation and oxidative stress. In addition to that, vitamin E can also modulate signal transduction and gene expression. To study whether the four natural tocopherol analogues (alpha-, beta-, gamma-, delta-tocopherol) can influence transcriptional activity by modulating the activity of nuclear receptors, a human keratinocytes cell line (NCTC 2544) was transfected with plasmids containing the luciferase reporter gene under control by direct repeat elements (DR1-DR4), representing binding sites for four different classes of nuclear receptors. In this model, the tocopherols positively modulated only the reporter construct containing a consensus element for peroxisome proliferator-activated receptors (PPARs). The induction was strongest with gamma-tocopherol and was most likely the direct consequence of stimulation of PPARgamma protein expression in keratinocytes. Vitamin E treatment also led to increased expression of a known PPARgamma target gene involved in terminal keratinocytes differentiation, the transglutaminase-1.
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In groundwater-fed fen peatlands, the surface biomass decays rapidly and, as a result, highly humified peat is formed. A high degree of humification constrains palaeoecological studies because reliable identification of plant remains is hampered. Organic geochemistry techniques as a means of identifying historical plant communities have been successfully applied tobog peat. The method has also been applied to fen peat, but without reference to the composition of fen plants. We have applied selected organic geochemistry methods to determine the composition of the neutral lipid fractions from 12 living fen plants, to investigate the potential for the distributions to characterize and separate different fen plants and plant groups. Our results show correspondence with previous studies, e.g. C23 and C25n-alkanes dominating Sphagnum spp. and C27 to C31 alkanes dominating vascular plants. However, we also found similarities in n-alkane distributions between Sphagnum spp. and the below ground parts of some vascular plants. We tested the efficiency of different n-alkane ratios to separate species and plant groups. The ratios used for bog studies (e.g. n-C23/n-C25 and n-C23/n-C29) did not work as consistently for fen plants. Some differences in sterol distribution were found between vascular plants and mosses; in general vascular plants had a higher concentration of sterols. When distributions of n-alkanes, n-alkane ratios and sterols were all included as variables, redundancy analysis (RDA) separated different plant groups into their own clusters. Our results imply that the pattern for bog biomarkers cannot directly be applied to fen environments. Nevertheless, they encourage further testing to determine whether or not the identification of plant groups, plants or plant parts from highly humified peat is possible by applying fen species-specific biomarker proxies.
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The chemical composition of surface associated metabolites of two Fucus species (Fucus vesiculosus and Fucus serratus) was analysed by means of gas chromatography-mass spectrometry (GC-MS) to describe temporal patterns in chemical surface composition. Method: The two perennial brown macroalgae F. vesiculosus and F. serratus were sampled monthly at Bülk, outer Kiel Fjord, Germany (54°27'21 N / 10°11'57 E) over an entire year (August 2012 - July 2013). Per month and species six non-fertile Fucus individuals were collected from mixed stands at a depth of 0.5 m under mid water level. For surface extraction approx. 50 g of the upper 5-10 cm apical thalli tips were cut off per species. The surface extraction of Fucus was performed according to the protocol of de Nys and co-workers (1998) with minor modifications (see Rickert et al. 2015). GC/EI-MS measurements were performed with a Waters GCT premier (Waters, Manchester, UK) coupled to an Agilent 6890N GC equipped with a DB-5 ms 30 m column (0.25 mm internal diameter, 0.25 mM film thickness, Agilent, USA). The inlet temperature was maintained at 250°C and samples were injected in split 10 mode. He carrier gas flow was adjusted to 1 ml min-1. Alkanes were used for referencing of retention times. For further details (GC-MS sample preparation and analysis) see the related publication (Rickert et al. submitted to PLOS ONE).
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alpha-Tocopherol is a lipid-soluble antioxidant that helps to prevent oxidative damage to cellular lipids. alpha-Tocopherol is absorbed by the intestine and is taken up and retained by the liver; it is widely presumed that alpha-tocopherol is then delivered to peripheral tissues by the secretion of VLDL. To determine whether VLDL secretion is truly important for the delivery of alpha-tocopherol to peripheral tissues, we examined alpha-tocopherol metabolism in mice that lack microsomal triglyceride transfer protein (Mttp) expression in the liver and therefore cannot secrete VLDL (Mttp(Delta/Delta) mice). Mttp(Delta/Delta) mice have low plasma lipid levels and increased stores of lipids in the liver. Similarly, alpha-tocopherol levels in the plasma were lower in Mttp(Delta/Delta) mice than in controls, whereas hepatic alpha-tocopherol stores were higher. However, alpha-tocopherol levels in the peripheral tissues of Mttp(Delta/Delta) mice were nearly identical to those of control mice, suggesting that VLDL secretion is not critical for the delivery of alpha-tocopherol to peripheral tissues. When fed a diet containing deuterated alpha-tocopherol, Mttp(Delta/Delta) and control mice had similar incorporation of deuterated alpha-tocopherol into plasma and various peripheral tissues. We conclude that the absence of VLDL secretion has little effect on the stores of alpha-tocopherol in peripheral tissues, at least in the mouse.
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The Alpha-Tocopherol Beta-Carotene Cancer Prevention Study has provided the first evidence implicating vitamin E in hormone synthesis. The effect of vitamin E on stereoidogenesis in testes and adrenal glands was assessed in growing rats using Affymetrix gene-chip technology. Dietary supplementation of rats with vitamin E (60 mg/kg feed) for a period of 429 days caused a significant repression of genes encoding for proteins centrally involved in the uptake (low-density lipoprotein receptor) and de novo synthesis (for example, 7-dehydrocholesterol reductase, 3-hydroxy-3-methylglutaryl coenzyme A synthase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, isopentenyl-diphosphate delta-isomerase, and farnesyl pyrophosphate synthetase) of cholesterol, the precursor of all steroid hormones. The present investigation indicates that dietary vitamin E may induce changes in stereoidogenesis by affecting cholesterol homeostasis.
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Natural vitamin E consists of four different tocopherol and four different tocotrienol homologues (alpha,beta, gamma, delta) that all have antioxidant activity. However, recent data indicate that the different vitamin E homologues also have biological activity unrelated to their antioxidant activity. In this review, we discuss the anti-inflammatory properties of the two major forms of vitamin E, alpha-tocopherol (alphaT) and gamma-tocopherol (gammaT), and discuss the potential molecular mechanisms involved in these effects. While both tocopherols exhibit anti-inflammatory activity in vitro and in vivo, supplementation with mixed (gammaT-enriched) tocopherols seems to be more potent than supplementation with alphaT alone. This may explain the mostly negative outcomes of the recent large-scale interventional chronic disease prevention trials with alphaT only and thus warrants further investigation.
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Ropivacaine (RVC) is an aminoamide local anesthetic widely used in surgical procedures. Studies with RVC encapsulated in liposomes and complexed in cyclodextrins have shown good results, but in order to use RVC for lengthy procedures and during the postoperative period, a still more prolonged anesthetic effect is required. This study therefore aimed to provide extended RVC release and increased upload using modified liposomes. Three types of vesicles were studied: (i) large multilamellar vesicle (LMV), (ii) large multivesicular vesicle (LMVV) and (iii) large unilamellar vesicle (LUV), prepared with egg phosphatidylcholine/cholesterol/α-tocopherol (4:3:0.07 mol%) at pH 7.4. Ionic gradient liposomes (inside: pH 5.5, pH 5.5 + (NH4)2SO4 and pH 7.4 + (NH4)2SO4) were prepared and showed improved RVC loading, compared to conventional liposomes (inside: pH 7.4). An high-performance liquid chromatography analytical method was validated for RVC quantification. The liposomes were characterized in terms of their size, zeta potential, polydispersion, morphology, RVC encapsulation efficiency (EE(%)) and in vitro RVC release. LMVV liposomes provided better performance than LMV or LUV. The best formulations were prepared using pH 5.5 (LMVV 5.5in) or pH 7.4 with 250 mM (NH4)2SO4 in the inner aqueous core (LMVV 7.4in + ammonium sulfate), enabling encapsulation of as much as 2% RVC, with high uptake (EE(%) ∼70%) and sustained release (∼25 h). The encapsulation of RVC in ionic gradient liposomes significantly extended the duration of release of the anesthetic, showing that this strategy could be a viable means of promoting longer-term anesthesia during surgical procedures and during the postoperative period.
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Purpose - This paper aims to evaluate the association between the a-tocopherol with the levels of serum anti-oxLDL autoantibodies and the risk markers for cardiovascular disease. Design/methodology/approach - A normolipidemic control group (n=30) and a hypercholesterolemic group (n=33) were used. Plasma lipid profile (colorimetric method), anti-oxLDL autoantibodies (ELISA) and a-tocopherol (HPLC) were analysed. Findings - The a-tocopherol (ß=-0.714; p=0.001) is negatively associated with anti-oxLDL autoantibodies in serum and with other risk markers for cardiovascular disease (BMI, WC, total cholesterol, LDL-c) and positively associated with HDL-c. Originality/value - Oxidized low density lipoprotein (oxLDL) and their autoantibodies are increased in subjects with hypercholesterolemia. The a-tocopherol can influence the levels of serum anti-oxLDL autoantibodies
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Background: Viral hepatitis B, C and delta still remain a serious problem worldwide. In Colombia, data from 1980s described that HBV and HDV infection are important causes of hepatitis, but little is known about HCV infection. The aim of this study was to determine the currently frequency of HBV, HCV and HDV in four different Colombian regions. Methodology/Principal Findings: This study was conducted in 697 habitants from 4 Colombian departments: Amazonas, Choco, Magdalena and San Andres Islands. Epidemiological data were obtained from an interview applied to each individual aiming to evaluate risk factors related to HBV, HCV or HDV infections. All samples were tested for HBsAg, anti-HBc, anti-HBs and anti-HCV markers. Samples that were positive to HBsAg and/or anti-HBc were tested to anti-HDV. Concerning the geographical origin of the samples, the three HBV markers showed a statistically significant difference: HBsAg (p = 0.033) and anti-HBc (p < 0.001) were more frequent in Amazonas and Magdalena departments. Isolated anti-HBs (a marker of previous vaccination) frequencies were: Choco (53.26%), Amazonas (32.88%), Magdalena (17.0%) and San Andres (15.33%) p < 0.001. Prevalence of anti-HBc increased with age; HBsAg varied from 1.97 to 8.39% (p = 0.033). Amazonas department showed the highest frequency for anti-HCV marker (5.68%), while the lowest frequency was found in San Andres Island (0.66%). Anti-HDV was found in 9 (5.20%) out of 173 anti-HBc and/or HBsAg positive samples, 8 of them from the Amazonas region and 1 from them Magdalena department. Conclusions/Significance: In conclusion, HBV, HCV and HDV infections are detected throughout Colombia in frequency levels that would place some areas as hyperendemic for HBV, especially those found in Amazonas and Magdalena departments. Novel strategies to increase HBV immunization in the rural population and to strengthen HCV surveillance are reinforced by these results.
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Tibolone is used for hormone reposition of postmenopause women and isotibolone is considered the major degradation product of tibolone. Isotibolone can also be present in tibolone API raw materials due to some inadequate synthesis. Its presence is then necessary to be identified and quantified in the quality control of both API and drug products. In this work we present the indexing of an isotibolone X-ray diffraction pattern measured with synchrotron light (lambda=1.2407 angstrom) in the transmission mode. The characterization of the isotibolone sample by IR spectroscopy, elemental analysis, and thermal analysis are also presented. The isotibolone crystallographic data are a=6.8066 angstrom, b=20.7350 angstrom, c=6.4489 angstrom, beta=76.428 degrees, V=884.75 angstrom(3), and space group P2(1), rho(o)= 1.187 g cm(-3), Z=2. (C) 2009 International Centre for Diffraction Data. [DOI: 10.1154/1.3257612]
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The present work integrates sedimentary facies, (14)C dating, delta(13)C, delta(15)N, and C/N with geologic and geomorphologic data available from literature. The aim was to characterize the depositional settings of a late Quaternary estuary in northeastern Marajo Island and analyze its evolution within the context of relative sea level fluctuations. The data derive from four continuous cores along a proximal-to-distal transect of a paleoestuary, previously recognized using remote sensing information. Fifteen sediment samples recorded ages ranging from 42,580 +/- 1430 to 3184 +/- 37 (14)C yr B.P. Fades analysis indicated fine- to coarse-grained sands with parallel lamination or cross stratification, massive or laminated muds and heterolithic deposits. delta(13)C (-28.1 parts per thousand to -19.7 parts per thousand, mean = -23.0 parts per thousand), delta(15)N (+ 14.8 parts per thousand to + 4.7 parts per thousand, mean = + 9.2 parts per thousand) and C/N (14.5 to 1.5, mean = 7.9) indicate mostly marine and freshwater phytoplankton sources for the organic matter. The results confirm a large late Quaternary paleoestuary in northeastern Marajo Island. The distribution of delta(13)C, delta(15)N, and C/N, together with fades associations, led to identify depositional settings related to fluvial channel, floodplain, tidal channel/tidal flat, central basin, tidal delta, and tidal inlet/sand barrier. These deposits are consistent with a wave-dominated estuary. Variations in stratigraphy and geochemistry are controlled by changes in relative sea level, revealing a main transgression from an undetermined time around 42,000 (14)C yr B.P. and 29,340 (+/- 200) (14)C yr B.P., which is synchronous to the overall drop in sea level after the last interglacial. Following this period, and probably until 9110 +/- 37 (14)C yr B.P., i.e., during a time interval encompassing two glacial episodes including the Last Glacial and the Younger Dryas, there was a pronounced drop in sea level, recorded by the development of a major erosional discontinuity due to valley re-incision. Sea level rose again until 5464 +/- 40 (14)C yr B.P, just before the main worldwide mid-Holocene transgressive peak. Mid to late Holocene coastal progradation ended the Marajo paleoestuarine history, and promoted the establishment of continental conditions throughout the island. The divergence comparing the Marajo sea level behavior with the eustatic curve allows hypothesizing that post-rifting tectonics along the Brazilian Equatorial margin influenced the sedimentary evolution of the studied paleoestuary. Considering that sedimentary facies in estuarine settings are highly variable both laterally and vertically, the present integration of facies with isotope and elemental analyses was crucial to provide a more precise interpretation of the Late Pleistocene and Holocene Marajo paleoestuary, and analyze its sea level history within the eustatic and tectonic context. (C) 2010 Elsevier B.V. All rights reserved.