INHIBITORY EFFECTS OF POLYPHENOLIC EXTRACTS OF BETULA PENDULA, SALIVA HYDRANGEA AND CRATAEGUS CURVISEPALA, AS WELL AS VITAMIN C, ON THE EXTENT OF GLYCOSYLATION OF ALBUMIN, INSULIN AND HEMOGLOBIN

Abstract

Introduction: Diabetes is one of the most common endocrine diseases spreading rapidly in the world. Diabetes complications are classified to acute and chronic. Non-enzymatic glycosylation of all body proteins, such as hemoglobin, albumin is the main cause of pathogenesis in chronic complications of diabetes. As glycosylation reaction of proteins is an oxidative reaction it seems that antioxidants, such as vitamin C, inhibit the reaction and, therefore, chronic complications of diabetes. In the present study inhibitory effects of polyphenolic extracts of Betula pendula, Saliva hydrangea and Crataegus curvisepala, as well as vitamin C, on the extent of glycosylation of albumin, insulin and hemoglobin was investigated. Methods: Polyphenolic extracts of the mentioned plants were prepared in three different concentrations; 3.6, 1.8, and 0.9 mg/ml also vitamin C solutions were prepared in 5 concentrations: 0.5, 5, 10, 50 and 500 µg/ml. Results: The highest extent of glycosylation inhibition of albumin and insulin was due to S.hydrangea by 100% and 97% respectively, and that of hemoglobin was due to a.pendula, by 80%. Vitamin C in its highest concentration inhibit glycosylation of insulin, albumin and hemoglobin by 100%, 93%, and 58% respectively (P < 0.05). Discussion: Based on the findings, it seems that these plants prevent chronic complications of diabetes.