Diabetes-correcting and antioxidant effects of grape pomace extract rich in natural complex of polyphenols

Background. The positive health effects of polyphenols have led to an increased scientific interest in these natural compounds over the past decade. Many studies confirm the effectiveness of polyphenols as additional therapy in diabetes, especially due to the sugar-lowering effect of polyphenols. The aim of the research was to investigate the morphological and functional state of peripheral blood erythrocytes and the indices of oxidative stress in the liver of rats with experimental diabetes and after the administration of grape pomace extract rich in natural complex of polyphenols. Materials and Methods. We obtained grape pomace extract, which contains a variety of polyphenolic compounds. Rats of the following groups were used in the experiments: control animals, animals treated with grape pomace extract rich in natural complex of polyphenols for 14 days, animals with streptozotocin-induced diabetes mellitus, and animals with streptozotocin-induced diabetes mellitus treated with grape pomace extract rich in natural complex of polyphenols for 14 days. The number of erythrocytes and reticulocytes, the concentration of hemoglobin and glycated hemoglobin were determined in the peripheral blood of rats. The activities of catalase, superoxide dismutase and the content of thiobarbituric acid-reactive substance and carbonyl groups of proteins were determined in the liver tissues of rats. Results. The study has shown an increase in the number of erythrocytes and the level of hemoglobin, a decrease in the level of glycated hemoglobin and the number of reticulocytes in the peripheral blood of rats after administration of grape pomace extract rich in natural complex of polyphenols to rats with experimental diabetes. A decrease in the content of thiobarbituric acid-reactive substance and the content of carbonyl groups of proteins of neutral and basic character and an increase in the activity of catalase and superoxide dismutase in liver tissues were found under the same conditions. Conclusions. The results indicate that the extract of the natural complex of polyphenols is capable of correcting the morphological and functional state of erythrocytes, as well as improving the activity of antioxidant enzymes and the content of marker molecules of oxidative stress in hepatocytes of rats under experimental diabetes mellitus.