Ameliorative effects of Penthorum chinense Pursh on insulin resistance and oxidative stress in diabetic obesity db/db mice.

BACKGROUND

Penthorum chinense Pursh (PCP), a medicinal and edible plant, has been reported to protect against liver damage by suppressing oxidative stress. Type 2 diabetes mellitus (T2DM) is associated with liver dysfunction and oxidative stress. In the present study, we aim to investigate the hypoglycemic effect of PCP on db/db mice and further explore the underlying mechanisms.

METHODS

Thirty-two db/db mice were randomized into four groups, including a diabetic model control group (MC) and three diabetic groups treated with low (LPCP, 300 mg/kg/d), medium (MPLP, 600 mg/kg/d), and high doses of PCP (HPCP, 1200 mg/kg/d), and the normal control group (NC) of eight db/m mice were included. Mice in the NC and MC groups received the ultrapure water. After four weeks of intervention, parameters of fasting blood glucose (FBG), insulin resistance (IR), blood lipid levels, hepatic oxidative stress, and enzymes related to hepatic glucose metabolism were compared in the groups.

RESULTS

PCP administration significantly reduced FBG and IR in diabetic db/db mice, and improved hepatic glucose metabolism by increasing glucose transporter 2 (GLUT2) and glucokinase (GCK) protein expression. Meanwhile, PCP supplementation ameliorated hepatic oxidative stress by decreasing malonaldehyde content and increasing the activities of superoxide dismutase and glutathione peroxidase in db/db mice. Furthermore, PCP treatment reduced obesity and food intake in db/db mice, and improved dyslipidemia demonstrated by increasing high-density lipoprotein cholesterol (HDL-C) while decreasing total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (HDL-C). All doses of PCP treatment decreased the values of LDL-C/HDL-C in a dose-response relationship.

CONCLUSION

PCP significantly alleviated hyperglycemia, hyperinsulinemia, hyperlipidemia, and obesity, inhibited hepatic oxidative stress, and enhanced hepatic glucose transport in T2DM mice. Based on the above findings, the hypoglycemic effect of PCP may be attributed to the activation of the GLUT2/GCK expression in the liver and the reduction of hepatic oxidative stress.