Low-dose grape pomace and omija fruit extract is more effective than high-dose in lowering oxidative stress and fat-pad mass in db/db mice

Previous studies have shown that the mixture of extracts of grape pomace and omija (GO) improved oxidative stress and obesity in mice. This study first investigated the dose–response effects of GO on oxidative stress and fat-pad mass. Male C57BL/KsJ-db/db mice were fed the following three experimental diets for 7 weeks: a normal control, high-dose grape pomace plus omija (HGO; 0.5% grape pomace plus 0.05% omija fruit, w/w), and low-dose grape pomace plus omija (LGO; 0.3% grape pomace plus 0.05% omija fruit, w/w). The LGO significantly decreased white adipose tissues weights, as well as ameliorated the plasma lipid profiles. The antioxidant effects of LGO led to a significant decrease in the erythrocytic H₂O₂ and thiobarbituric acid-reactive substance levels, while LGO increased erythrocytic antioxidant activities. These results suggest that LGO is more effective than HGO in lowering oxidative stress and body fat mass in db/db mice.