Anti-Diabetic Effect of Pectinase-Processed Ginseng Radix (GINST) in High Fat Diet-Fed ICR Mice

Abstract

In the present study, we investigate anti-diabetic effect of pectinase-processed ginseng radix (GINST) in high fat diet-fed ICR mice. The ICR mice were divided into three groups: regular diet group, high fat diet control group (HFD), and GINST-treated group. To induce hyperglycemia, mice were fed a high fat diet for 10 weeks, and mice were administered with 300 mg/ kg of GINST once a day for 5 weeks. Oral glucose tolerance test revealed that GINST improved glucose tolerance after glucose challenge. Compared to the HFD control group, fasting blood glucose and insulin levels were decreased by 57.8% (p<0.05) and 30.9% (p<0.01) in GINST-treated group, respectively. With decreased plasma glucose and insulin levels, the insulin resistance index of the GINST-treated group was reduced by 68.1% (p<0.01) compared to the HFD control group. Pancreas of GINST-treated mice preserved a morphological integrity of islets and consequently having more insulin contents. In addition, GINST up-regulated the levels of phosphorylated AMP-activated protein kinase (AMPK) and its target molecule, glucose transporter 4 (GLUT4) protein expression in the skeletal muscle. Our results suggest that GINST ameliorates a hyperglycemia through activation of AMPK/ GLUT4 signaling pathway, and has a therapeutic potential for type 2 diabetes.

Keywords: AMP-activated protein kinase; Glucose transporter type 4; High fat diet; Panax ginseng; Pectinase-processed ginseng radix.

Fig. 1.. Ultra performance liquid chromatography profiles of ginseng radix (A) and pectinase-processed ginseng radix (B).

Fig. 2.. Plasma glucose responses to an oral glucose challenge (1.5 g/kg) after 12 h food deprivation in ICR mice. Plasma glucose response to an oral glucose challenge (A), and the area under the curve of plasma glucose concentration versus time (B). Values are mean±SE (n=5) and *p<0.05 compared to high fat diet control group. RD, regular diet; HFD, high fat diet; GINST, pectinase-processed ginseng radix.

Fig. 3.. Effect of pectinase-processed ginseng radix on pancreas morphology. Panel A represents H&E staining and panel B represents insulin immunostaining (× 200). Con, control; HFD, high fat diet; GINST, pectinase-processed ginseng radix.

Fig. 4.. Effects of pectinase-processed ginseng radix on pAMPK, pACC, and GLUT4 protein expression measured via Western blot analyses (A) and their densitometric analyses (B). RD, regular diet; HFD, high fat diet; GINST, pectinase-processed ginseng radix.