Comparison of the antioxidant effects of Concord grape juice flavonoids alpha-tocopherol on markers of oxidative stress in healthy adults.
BACKGROUND
Concord grape juice (CGJ) is a rich source of flavonoids, which have greater antioxidant efficacy in vitro than does alpha-tocopherol; however, the efficacies of flavonoids and alpha-tocopherol in vivo have not been compared.


OBJECTIVE
We compared the in vivo antioxidant efficacy of CGJ with that of alpha-tocopherol in healthy adults.


METHODS
Subjects were randomly assigned to receive either 400 IU RRR-alpha-tocopherol/d (n = 17) or 10 mL CGJ. kg(-1). d(-1) (n = 15) for 2 wk. Serum oxygen radical absorbance capacity, plasma protein carbonyls, urinary F(2)-isoprostanes, and resistance of LDL to ex vivo oxidation were measured before and after supplementation as markers of antioxidant status and oxidative stress.


RESULTS
After supplementation, plasma alpha-tocopherol increased 92% in subjects who received alpha-tocopherol (P < 0.001); plasma total and conjugated phenols increased 17% (P < 0.01) and 22% (P < 0.001), respectively, in subjects who received CGJ. There was a significant change in plasma triacylglycerols in both groups, but the concentrations were within the normal range. CGJ supplementation was associated with significantly higher triacylglycerols than was alpha-tocopherol supplementation. Both supplementation regimens significantly increased serum oxygen radical absorbance capacity (P < 0.001) and LDL lag time (P < 0.001) and significantly decreased the LDL oxidation rate (P < 0.01), with no significant difference in effectiveness. Protein carbonyl concentrations in native plasma decreased 20% after CGJ supplementation, which was a significantly different response than that after alpha-tocopherol supplementation (P < 0.05).


CONCLUSIONS
In healthy adults, 10 mL CGJ. kg(-1). d(-1) increased serum antioxidant capacity and protected LDL against oxidation to an extent similar to that obtained with 400 IU alpha-tocopherol/d but decreased native plasma protein oxidation significantly more than did alpha-tocopherol. CGJ flavonoids are potent antioxidants that may protect against oxidative stress and reduce the risk of free radical damage and chronic diseases.
O'Byrne
Dawn J
DJ
Center for Human Nutrition and the Division of Clinical Biochemistry and Human Metabolism, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, USA.
Devaraj
Sridevi
S
Grundy
Scott M
SM
Jialal
Ishwarlal
I
D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000097:blood; D001628:Beverages / Q000032:analysis*; D001798:Blood Proteins / Q000032:analysis; D019587:Dietary Supplements; D028441:F2-Isoprostanes / Q000652:urine; D005419:Flavonoids / Q000494:pharmacology*; D016166:Free Radical Scavengers; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008077:Lipoproteins, LDL / Q000097:blood; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000097:blood; D027843:Vitis / Q000737:chemistry*; D024502:alpha-Tocopherol / Q000097:blood / Q000494:pharmacology*
D000975:Antioxidants; D001798:Blood Proteins; D028441:F2-Isoprostanes; D005419:Flavonoids; D016166:Free Radical Scavengers; D008077:Lipoproteins, LDL; D017382:Reactive Oxygen Species; D024502:alpha-Tocopherol; D001205:Ascorbic Acid