Study of antidiabetic activity of white skinned sweet potato (Ipomoea batatas L.): Comparison of normal and streptozotocin induced diabetic rats and hereditary diabetic mice

Abstract

White skinned sweet potato (Ipomoea batatas L.) cortex (WSSP-cortex) was found to have potential hypoglycemic activity in streptozotosin (STZ) induced diabetic rats and hereditary diabetic mice (Type II, KK-AY/Ta Jcl, C57BL/KsJ db/db) by oral administration. However, in normal rats, serum glucose levels were not changed by WSSP-cortex treatment. In glucose tolerance tests, treatment of normal and STZ diabetic rats by WSSP-cortex showed increased glucose tolerance and increased serum insulin levels like the tolbutamide treatment, whereas the treatment of KK-AY and db/db mice showed increased glucose tolerance and decreased serum insulin levels different from the tolbutamide treatment in response to oral glucose load. These results suggest that the WSSP-cortex has quite unique properties such as the increase of insulin secretion and improving insulin resistance.