The effect of grape-skin extract on oxidative status

Br J Nutr. 2000 Oct;84(4):505-13.

Abstract

Epidemiological studies indicate that moderate alcohol consumption, particularly wine, reduce the risk of CHD. The present study was designed to investigate the effect of grape-skin extract on markers of oxidative status. The study was designed as a randomised crossover. A diet with a low content of flavonoids was served with strict control of intake in two consecutive 1-week intervention periods to fifteen subjects (nine women, six men) divided randomly into two groups. During one of the weeks the subjects from either group consumed 200 ml grape-skin extract in water (1 mg extract/ml) at each of three daily meals (31.3 mg total phenolics, including 9.0 mg catechin). An increased activity of glutathione reductase and a borderline increase of glutathione peroxidase activity in erythrocytes were observed after grape-skin intervention, while the intervention had no significant effect on superoxide dismutase or catalase. Likewise, no effect was found on 2-aminoadipic semialdehyde (AAS) residues, a plasma protein oxidation product, or on malondialdehyde in plasma or in LDL, which are markers of lipoprotein oxidation. A marginal effect of grape-skin intervention was observed on plasma ascorbate levels. Intake of the experimental diet significantly reduced plasma vitamin C and plasma AAS in both groups. This effect was most pronounced in the particular week with no grape-skin extract addition. We speculate that grape-skin extract may have a sparing effect on vitamin C. The effects of the experimental diet may be partly ascribed to a low content of several fruit- and vegetable-related antioxidants like flavonoids and vitamin C and a relatively high content of carrot-derived antioxidants, such as carotenes.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Aminoadipic Acid / analogs & derivatives
  • 2-Aminoadipic Acid / blood
  • Adult
  • Analysis of Variance
  • Antioxidants / analysis*
  • Ascorbic Acid / blood*
  • Biomarkers / blood
  • Catalase / metabolism
  • Cross-Over Studies
  • Erythrocytes / enzymology*
  • Female
  • Flavonoids / administration & dosage*
  • Glutathione Peroxidase / metabolism*
  • Glutathione Reductase / metabolism*
  • Humans
  • Lipoproteins, LDL / chemistry
  • Male
  • Malondialdehyde / analysis
  • Malondialdehyde / blood
  • Oxidation-Reduction
  • Rosales / chemistry*
  • Superoxide Dismutase / metabolism

Substances

  • Antioxidants
  • Biomarkers
  • Flavonoids
  • Lipoproteins, LDL
  • 2-Aminoadipic Acid
  • allysine
  • Malondialdehyde
  • Catalase
  • Glutathione Peroxidase
  • Superoxide Dismutase
  • Glutathione Reductase
  • Ascorbic Acid