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| 2. |
- Frank, J., et al.
(författare)
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Dietary flavonoids with a catechol structure increase alpha-tocopherol in rats and protect the vitamin from oxidation in vitro
- 2006
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Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 47:12, s. 2718-2725
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Tidskriftsartikel (refereegranskat)abstract
- To identify dietary phenolic compounds capable of improving vitamin E status, male Sprague-Dawleyrats were fed for 4 weeks either a basal diet ( control) with 2 g/kg cholesterol and an adequate content of vitamin E or the basal diet fortified with quercetin ( Q), (2)-epicatechin (EC), or (1)-catechin ( C) at concentrations of 2 g/kg. All three catechol derivatives substantially increased concentrations of alpha-tocopherol (alpha-T) in blood plasma and liver. To study potential mechanisms underlying the observed increase of alpha-T, the capacities of the Flavonoids to i) protect alpha-T from oxidation in LDL exposed to peroxyl radicals, ii) reduce alpha-tocopheroxyl radicals (alpha-T-.) in SDS micelles, and iii) inhibit the metabolism of tocopherols in HepG2 cells were determined. All flavonoids protected alpha-T from oxidation in human LDL ex vivo and dose-dependently reduced the concentrations of alpha-T-.. None of the test compounds affected vitamin E metabolism in the hepatocyte cultures. In conclusion, fortification of the diet of Sprague-Dawley rats with Q, EC, or C considerably improved their vitamin E status. The underlying mechanism does not appear to involve vitamin E metabolism but may involve direct quenching of free radicals or reduction of the alpha-T-. by the flavonoids.
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| 6. |
- Alam, Muneeba Zubair, et al.
(författare)
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Soluble and hydrolyzable phenolic compounds in date fruits (Phoenix dactylifera L.) by UPLC-QTOF-MS/MS and UPLC-DAD
- 2024
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Ingår i: Journal of Food Composition and Analysis. - 0889-1575 .- 1096-0481. ; 132
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Tidskriftsartikel (refereegranskat)abstract
- Phenolic compounds in plant foods exist in soluble, hydrolyzable, and insoluble forms. This study is the first to analyze both soluble (extracted using 80 % methanol) and hydrolyzable (extracted using ethyl acetate after alkaline hydrolysis) phenolics in 18 date cultivars. The phenolic compounds were identified and quantified using ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry and diode array detectors. A total of 59 peaks were detected, of which 45 were identified while 14 remained unidentified. The concentrations of the soluble and hydrolyzable phenolics ranged from 27.5–54.0 and 24–78.5 mg/100 g fresh weight, respectively. Gallic acid and ferulic acid predominated in the soluble and hydrolyzable fractions, quercetin and taxifolin were predominant in the soluble fraction, while caffeic acid and chlorogenic acid were abundant in the hydrolyzable fraction. The hydrolyzable phenolics were found to contribute significantly to the total phenolic content of date fruits pointing to the need to include them in the analysis of total phenolic compounds in foods.
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| 10. |
- Kamal-Eldin, A., et al.
(författare)
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Potential Negative Effects of Whole grain Consumption
- 2021
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Ingår i: Whole Grains and Health: Second Edition. - : Wiley.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter discusses the acclaimed adverse effects of some constituents of whole grain cereals and their bran, including allergenic proteins and proteins that provoke food sensitivity; toxic effects of the heavy metal cadmium; phytate and phenolic compounds for their chelation of iron; and acrylamide, which is a heat- generated class II carcinogen. The possible adverse effects related to whole grain consumption are important to consider with increased consumption of whole grains and especially bran-rich fractions. Some of the cereal proteins may provoke immune responses causing allergies or trigger autoimmune responses leading to food sensitivity in genetically predisposed individuals. Gluten proteins, which is a collective name for glutamin and prolamin-rich proteins, such as gliadin in wheat, hordeins in barley and secalins in rye, may trigger celiac disease in genetically predisposed individuals carrying, for example, the HLA-DQ8 and/or HLA-DQ2 genotypes.
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| 11. |
- Landberg, Rikard, 1981, et al.
(författare)
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New alkylresorcinol metabolites in spot urine as biomarkers of whole grain wheat and rye intake in a Swedish middle-aged population
- 2018
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Ingår i: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 72:10, s. 1439-1446
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Tidskriftsartikel (refereegranskat)abstract
- Background/objectives: Studies on the health effects of whole grains typically use self-reported intakes which are prone to large measurement errors. Dietary biomarkers that can provide an objective measure of intake are needed. New alkylresorcinol (AR) metabolites (3,5-dihydroxycinnamic acid (DHCA), 2-(3,5-dihydroxybenzamido)acetic acid (DHBA-glycine) and 5-(3,5-dihydroxyphenyl) pentanoic acid (DHPPTA)) in 24 h urine samples have been suggested as biomarkers for whole grain (WG) wheat and rye intake but remain to be evaluated in spot urine samples. Subjects/methods: The reproducibility of the new AR metabolites (DHCA, DHBA-glycine and DHPPTA) was investigated in 4 repeated samples over a period of 2 wk in spot urine from 40 Swedish men and women enroled in the SCAPIS-study, after adjustment of creatinine. Metabolite concentrations were correlated with total whole grain intake estimated during the same period. Results: The medium-term reproducibility determined for DHCA, DHPPTA and DHBA-glycine varied from moderate to excellent (intra-class correlation coefficient = 0.35–0.67). Moreover, DHCA and DHBA-glycine were independently associated with self-reported total WG intake (β = 0.18, P = 0.08 and β = 0.18, P = 0.02, respectively) and all metabolites except for DHPPA were higher among women. Conclusions: This study supports the idea of using AR metabolites in one or several spot urine samples as biomarkers of whole grain intake. These findings need to be confirmed in different populations.
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| 13. |
- Marklund, Matti, et al.
(författare)
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Chain length of dietary alkylresorcinols affects their in vivo elimination kinetics in rats
- 2013
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 143:10, s. 1573-1578
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Tidskriftsartikel (refereegranskat)abstract
- Two phenolic acids, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)- propanoic acid (DHPPA), are the major metabolites of cereal alkylresorcinols (ARs). Like their precursors, AR metabolites have been suggested as biomarkers for intake of whole-grain wheat and rye and as such could aid the understanding of diet-disease associations. This study estimated and compared pharmacokinetic parameters of ARs and their metabolites in rats and investigated differences in metabolite formation after ingestion of different AR homologs. Rats were i.v. infused for 30 min with 2, 12, or 23 μmol/kg DHBA or DHPPA or orally given the same amounts of the AR homologs, C17:0 and C25:0. Repeated plasma samples, obtained from rats for 6 h (i.v.) or 36 h (oral), were simultaneously analyzed for ARs and their metabolites by GC-mass spectrometry. Pharmacokinetic parameters were estimated by population-based compartmental modeling and noncompartmental calculation. A 1-compartment model best described C25:0 pharmacokinetics, whereas C17:0 and AR metabolites best fitted 2-compartment models. Combined models for simultaneous prediction of AR and metabolite concentration were more complex, with less reliable estimates of pharmacokinetic parameters. Although the AUC of C17:0 was lower than that of C25:0 (P < 0.05), the total amount and composition of AR metabolites did not differ between rats given C17:0 or C25:0. The elimination half-life of ARs and their metabolites increased with length of the side chain (P-trend < 0.001) and ranged from 1.2 h (DHBA) to 8.8 h (C25:0). The formation of AR metabolites was slower than their elimination, indicating that the rate of AR metabolism and not excretion of DHBA and DHPPA determines their plasma concentrations in rats.
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| 14. |
- Marklund, Matti, et al.
(författare)
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Simultaneous pharmacokinetic modeling of alkylresorcinols and their main metabolites indicates dual absorption mechanisms and enterohepatic elimination in humans
- 2014
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166 .- 1541-6100. ; 144:11, s. 1674-1680
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alkylresorcinols have proven to be useful biomarkers of whole-grain wheat and rye intake in many nutritional studies. To improve their utility, more knowledge regarding the fate of alkylresorcinols and their metabolites after consumption is needed.OBJECTIVE: The objective of this study was to develop a combined pharmacokinetic model for plasma concentrations of alkylresorcinols and their 2 major metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA).METHODS: The model was established by using plasma samples collected from 3 women and 2 men after a single dose (120 g) of rye bran and validated against fasting plasma concentrations from 8 women and 7 men with controlled rye bran intake (23, 45, or 90 g/d). Alkylresorcinols in the lymph and plasma of a pig fed a single alkylresorcinol dose (1.3 mmol) were quantified to assess absorption. Human ileostomal effluent and pig bile after high and low alkylresorcinol doses were analyzed to evaluate biliary alkylresorcinol metabolite excretion.RESULTS: The model contained 2 absorption compartments: 1 that transferred alkylresorcinols directly to the systematic circulation and 1 in which a proportion of absorbed alkylresorcinols was metabolized before reaching the systemic circulation. Plasma concentrations of alkylresorcinols and their metabolites depended on absorption and formation, respectively, and the mean ± SEM terminal elimination half-life of alkylresorcinols (1.9 ± 0.59 h), DHPPA (1.5 ± 0.26 h), and DHBA (1.3 ± 0.22 h) did not differ. The model accurately predicted alkylresorcinol and DHBA concentrations after repeated alkylresorcinol intake but DHPPA concentration was overpredicted, possibly because of poorly modeled enterohepatic circulation. During the 8 h following administration, <2% of the alkylresorcinol dose was recovered in the lymph. DHPPA was identified in both human ileostomal effluent and pig bile, indicating availability of DHPPA for absorption and enterohepatic circulation.CONCLUSION: Intact alkylresorcinols have advantages over DHBA and DHPPA as plasma biomarkers for whole-grain wheat and rye intake because of lower susceptibility to factors other than alkylresorcinol intake.
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| 15. |
- Moazzami, Ali A., et al.
(författare)
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Dietary phytosterols inhibit the lipid modulating effects of sesamin in rats
- 2007
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Ingår i: Current Topics in Nutraceutical Research. - 1540-7535. ; 5:2-3, s. 93-97
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Tidskriftsartikel (refereegranskat)abstract
- The major lignan in the unsaponifiable fraction of sesame lipids, sesamin, is known to affect lipid metabolism. For example, sesamin inhibits the clearance of tocopherols, the activity of Delta 5-desaturase during fatty acid metabolism, and reduces cholesterol absorption and biosynthesis. In order to study whether dietary phytosterols, which are known to reduce the absorption of lipid soluble dietary factors, may influence the lipid-modulating effects of sesamin, rats were fed, in a 2x2 Latin-square design, diets containing two concentrations of sesamin and pbytosterols for 4 weeks. Tocopherols and cholesterol were analyzed in plasma and liver and the fatty acid profile was determined in liver lipids. Sesamin increased a-tocopherol concentrations in plasma and liver (p< 0. 001), whereas the phytosterols had no effect. However, an increase in the phytosterol content of the diet resulted in a reduction of the alpha-tocopherol-elevating effect of sesamin in plasma (p< 0. 01). Similarly, sesamin increased the percentage of dihomo-gamma-linolenic acid in liver lipids (p<0.05), which was abolished by the addition of pbytosterols. Neither sesamin nor phytosterols significantly altered cholesterol concentrations in plasma or liver. In conclusion, these results suggest that in rats, dietary phytosterols may interact with sesamin in a way reducing its biological activities.
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| 16. |
- Nälsén, C, et al.
(författare)
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Plasma antioxidant capacity among middle-aged men : the contribution of uric acid
- 2006
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 66:3, s. 239-248
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Although assays of plasma antioxidant capacity encompass interactions between various antioxidants, uric acid concentration can exert a predominant effect on results. Therefore, individual differences in uric acid concentration may explain a many of the differences in antioxidant capacity. The objective of this study was to measure the antioxidant capacity of plasma samples with and without uric acid in order to provide more information about how the concept of antioxidant capacity could be applied. Material and methods. Antioxidant capacity was measured using an enhanced chemiluminescence assay, and uric acid was removed from the samples using uricase. Results. Antioxidant capacity was positively correlated with uric acid concentration, body mass index, waist circumference, abdominal sagittal diameter and the concentrations of insulin and triglycerides. These correlations were not evident when uric acid was eliminated from the sample, but antioxidant capacity was correlated with lipid concentration; this may partly reflect tocopherols that are transported by lipid molecules. Conclusions. The significance of the contribution of uric acid to the antioxidant capacity could differ according to the type of study. Antioxidant capacity measurements in cross‐sectional studies may be presented both with and without the contribution of uric acid, because the absence of such data complicates interpretation of results when different populations are compared.
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