Effects of grape consumption on plasma and erythrocyte antioxidant parameters in elderly subjects

Aim: Effects of ingesting Fructus vitis minuta (black grape) on plasma and erythrocyte antioxidant parameters of elderly subjects were investigated in this study. Dried black grape (Maras uzumu for Turkish name) contain water (approx. 80% v/w), sugars (glucose and fructose) (appprox. 15% w/w) lipids, proteins, phenolic compounds, some minerals and vitamins. Methods: Thirteen subjects (mean age 74.67±0.58) participated in the study. They ingested grape at the daily dose of 1g/kg body weight for 1 month. Before and after these periods, fasting blood samples were obtained, and oxidant (malondialdehyde, MDA (nmol/mg protein), and xanthine oxidase, XO(mIU/mL)) and antioxidant (superoxide dismutase, SOD (U/mg protein) and glutathione peroxidase, GSH-Px (IU/mg protein)and catalase, CAT (IU/mg protein)) parameters were studied in erythrocytes, and MDA levels were studied in plasma samples obtained from the subjects. SOD, GSH-Px and CAT activities were measured in erythrocyte hemolysate fraction. Results: In the erythrocyte hemolysate, MDA levels and SOD activities were found to be lower (P<0.01) in the second samples relative to the first ones. Xanthine oxidase activity was found to be lower in the second samples, but this decrease was not statistically meaningful. Because of free radical production was decreased, SOD activities were not increased. Our results show that ingestion of grape consumption leads to significantly lowered erythrocyte MDA levels, which indicate that consumption of grape decreases oxidation reactions. It is quite possible that reduced peroxidation processes due to grape consumption may play a part in some of the beneficial effects of grape in elderly subjects.