Antidiabetic activity of Callicarpa nudiflora extract in type 2 diabetic rats via activation of the AMPK-ACC pathway

Objective:To evaluate the antidiabetic effect of Callicarpa nudiflora extract in streptozotoc-ininduced diabetic rats.Methods:The chemical constituents in Callicarpa nudiflora extract were identified by UPLCQ-TOF-MS.Callicarpa nudiflora extract(0.15 and 0.3 g/kg)was orally administered to streptozotocin-induced diabetic rats for 42 d.The effects of Callicarpa nudiflora extract on body weight,blood glucose,serum insulin,total cholesterol,triglyceride,LDL-C and HDL-C were investigated,and its effect on liver and pancreatic pathology was assessed by histopathological analysis.Moreover,the expression levels of adenosine 5’-monophosphate-activated protein kinase(AMPK),glucose transporter type 4(GLUT4),phospho-AMPK/AMPK,and p-acetylcoA carboxylase(P-ACC)/ACC in the skeletal muscles and liver were determined by reverse transcription-polymerase chain reaction,Western blotting,and immunohistochemistry.Results:A total of 34 compounds,including 8 iridoids,14 phenylpropanoids,and 12 flavonoids,were identified from Callicarpa nudiflora extract.Callicarpa nudiflora extract significantly reduced blood glucose and significantly restored all other biochemical parameters to near normal levels,including serum insulin,total cholesterol,triglyceride,LDL-C,and HDL-C.Callicarpa nudiflora extract improved insulin resistance and reversed the damage in the liver and pancreas caused by diabetes.Furthermore,Callicarpa nudiflora extract increased the expression levels of phospho-AMPK,GLUT4,P-ACC,and insulin receptor substrate-1 and decreased the expression level of PPAR r in diabetic rats.Conclusions:Callicarpa nudiflora extract improved oral glucose tolerance,lipid metabolism,insulin resistance,and reversed the diabetes-related damage in the liver and pancreas by activating the AMPK-ACC pathway.