Flavonoid metabolites and susceptibility of rat lipoproteins to oxidation

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 287; no. 6; pp. H2819 - H2824
• Main Authors: Benito, Sonia, Buxaderas, Susana, Mitjavila, M. Teresa
• Format: Journal Article
• Language: English
• Published: United States 01.12.2004
• Subjects: alpha-Tocopherol - blood; Animal Feed; Animals; Arteriosclerosis - blood; Arteriosclerosis - prevention & control; Catechin - blood; Catechin - pharmacokinetics; Cholesterol, LDL - metabolism; Flavonoids - blood; Flavonoids - pharmacokinetics; Lipoproteins - metabolism; Male; Oxidation-Reduction; Quercetin - blood; Quercetin - pharmacokinetics; Rats; Rats, Sprague-Dawley; Vitamin A - blood; Wine
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00471.2004

1 Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona; and 2 Departament de Nutrició i Bromatologia, Facultat de Farmàcia, Universitat de Barcelona, E-08028 Barcelona, Spain Submitted 20 May 2004 ; accepted in final form 30 July 2004 Flavonoids are ingested with vegetables and beverages and exert a beneficial effect on cardiovascular disease. Studies in animals in vitro and in humans ex vivo on the resistance of lipoproteins to oxidation are not consistent and the mechanisms by which flavonoids protect against atherosclerosis are a matter of debate. In the present study, we investigated the effects of administering diets containing 0.3% (wt/wt) quercetin, 0.3% (wt/wt) catechin, or 35% (vol/wt) dealcoholated red wine (DRW) for 10 days in healthy rats on markers of oxidative damage in lipoproteins and in plasma. The antioxidant levels in low-density lipoproteins (LDL) or the lag phase, oxidation rate, and maximum level of conjugated dienes during ex vivo LDL oxidation did not differ between control and treated rats. Plasma levels of -tocopherol and retinol were similar in all groups. The total antioxidant status of the plasma from rats fed either quercetin or DRW diet was higher than in control rats. Only glucuronide and sulfate compounds of quercetin were detected in plasma from rats fed the quercetin-rich diet, and no flavonoids or their metabolites were detected in plasma or LDL from rats fed the catechin- or the DRW-rich diet. No significant differences in malondialdehyde or in conjugated dienes in plasma were observed. These results indicate that although metabolites from quercetin are present in plasma, they are not detected in lipoproteins and do not modify the level of other antioxidants. In conclusion, in the absence of any pathology or of oxidative stress the intake of quercetin, catechin, or DRW did not protect lipoproteins from oxidation ex vivo. quercetin; catechin; wine; antioxidants; atherosclerosis Address for reprint requests and other correspondence: M. T. Mitjavila, Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 645, E-08028 Barcelona, Spain (E-mail: mmitjavila{at}ub.edu )