Effects of different grape formulations on antioxidative capacity, lipid peroxidation and oxidative DNA damage in aged rats

Abstract

In this study, the freeze-dried powders from whole grapes, pomace and juice of Campbell Early (Vitis labruscana Bailey) were prepared to determine the amount of total flavonoids, vitamins A, C, and E, and dietary fiber. Effects of whole grape, pomace, or juice intakes on their antioxidative capacity and DNA damage were investigated in Sprague-Dawley male rats. A total of 120 rats at 13 mo old and weighing 549±4 g were blocked into 8 groups according to body weight and raised for 3, 5, or 7 mo with diets containing 2% (w/w) dry powder of three different parts of grapes and 0.02% (w/w) CdCl 2. The contents of flavonoids, antioxidant vitamins A and E, and dietary fiber in freeze-dried powder were the highest in grape pomace, but the vitamin C contents were similar among the three powders. In all the 16, 18, and 20-mo-old animals, plasma and liver thiobarbituric acid reactive substances levels of grape-ingesting groups were lower than those of the controls and that of the grape pomace group was the lowest among the groups. Cd administration increased plasma and liver thiobarbituric acid reactive substances levels remarkably; however, Cd+grape groups were lower than the Cd-control group. Red blood cell superoxide dismutase activity of 18- and 20-mo-old rats was higher than that of 16-mo-olds, showing an age-related increase; however, red blood cell catalase and glutathione peroxidase activities decreased with age. Grape diets promoted superoxide dismutase, catalase, glutathione peroxidase activities, and the grape pomace increased the activities most significantly among three different parts of the grape. Cd decreased superoxide dismutase, catalase, glutathione peroxidase activities; however Cd+grape groups showed similar activities to the non-Cd control group. Liver superoxide dismutase activity was decreased with age but catalase activity of 18-mo-old rats was higher than those of 16- and 20-mo-old groups, and glutathione peroxidase activities of 16- and 18-mo-old groups were similar but that of 20-mo-old groups decreased markedly. Grape intake increased these three antioxidative enzyme activities while Cd administration decreased catalase and glutathione peroxidase activities except superoxide dismutase activity. The concentration in the kidney of 8-hydroxy-2′-deoxyguanosine in the 18- and 20-mo-old rats was higher than that in the 16-mo-old groups, and grape intake showed a protecting effect on DNA from age-related or Cd-induced oxidative damage. In conclusion, grape intakes, especially grape pomace with the highest content of flavonoids, β-carotene, tocopherols and dietary fiber among the three parts, showed the prominent antioxidative capacity of inhibiting age-related or Cd-induced increase of lipid peroxidation and DNA damage effectively, promoting liver and red blood cell antioxidant enzyme activities.