Anti-Diabetic Effect of Aster sphathulifolius in C57BL/KsJ-db/db Mice.

ABSTRACT

In this study, we investigated the anti-diabetic effect of Aster sphathulifolius (AS) extract in C57BL/KsJ-db/db mice. The db/db mice were orally administered with AS 50% ethanol extract at concentrations of 50, 100, and 200 mg/kg/day (db/db-AS50, db/db-AS100, and db/db-AS200, respectively) for 10 weeks. Food and water intake, fasting blood glucose concentrations, blood glycosylated hemoglobin levels, and plasma insulin levels were significantly lower in the db/db-AS200 group than in the vehicle-treated db/db group; whereas glucose tolerance was significantly improved in the db/db-AS200 group. Moreover, AS dose dependently increased both insulin receptor substrate 1 and glucose transporter type 4 expression in skeletal muscle, significantly increased glucokinase expression, and decreased glucose 6-phosphatase and phosphoenolpyruvate carboxykinase expressions in the liver. The expressions of transcription factors, such as sterol-regulatory element-binding protein, peroxisome proliferator-activated receptor γ, and adipocyte protein 2, were upregulated in adipose tissue. Furthermore, immunohistochemical analysis showed that AS upregulated insulin production by increasing pancreatic ß-cell mass. In summary, AS extract normalized hyperglycemia by multiple mechanisms inhibition of glyconeogenesis, acceleration of glucose metabolism and lipid metabolism, and increase of glucose uptake. Using in vivo assays, this study has shown the potential of AS as a medicinal food and suggests the efficacy of AS for the use of prevention of diabetes.