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Research article - Peer-reviewed, 2006

Dietary flavonoids with a catechol structure increase alpha-tocopherol in rats and protect the vitamin from oxidation in vitro

Frank J, Budek A, Lundh T, Parker RS, Swanson JE, Lourenco CF, Gago B, Laranjinha J, Vessby B, Kamal-Eldin A


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

Published in

Journal of Lipid Research
2006, volume: 47, number: 12, pages: 2718-2725

Authors' information

Frank, Jan
Swedish University of Agricultural Sciences, Department of Food Science
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Kamal-Eldin, Afaf
Swedish University of Agricultural Sciences, Department of Food Science
Gago, Bruno
Laranjihna, Joao
Lourenco, Catina F.
Swanson, Joy E.
Vessby, Bengt
Parker, Robert
Budek, Alicja
Swedish University of Agricultural Sciences, Department of Food Science

UKÄ Subject classification

Food Science

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