A refined-JinQi-JiangTang tablet ameliorates prediabetes by reducing insulin resistance and improving beta cell function in mice

Abstract Ethnopharmacological relevance Refined-JQ (JQ-R) is a mixture of refined extracts from three major herbal components of JinQi-JiangTang tablet: Coptis chinensis (Ranunculaceae), Astragalus membranaceus (Leguminosae), and Lonicera japonica (Caprifoliaceae). Our previous studies have indicated that JQ-R could decrease fasting blood glucose levels in diabetic mice and insulin resistance mice. Investigating the hypoglycemic effect of JQ-R on prediabetes has practical application value for preventing or delaying insulin resistance, impaired glucose tolerance and possibly the development of clinical diabetes. Materials and methods The anti-diabetic potential of JQ-R was investigated using a high fat-diet (HFD)-induced obesity mouse model. C57BL/6J mice (HFD-C57 mice) were fed with high-fat diet for 4 months. HFD-C57 mice were treated with either JQ-R (administered intragastrically once daily for 4 weeks) or metformin (as positive control), and the effects of JQ-R on body weight, blood lipids, glucose metabolism, insulin sensitivity, and beta cell function were monitored. Results The body weight, serum cholesterol, and the Homeostasis Model Assessment ratio (insulin resistance index) were significantly reduced in JQ-R or metformin-treated mice, and the glucose tolerance was enhanced and insulin response was improved simultaneously. Moreover, both JQ-R and metformin could activate liver glycogen syntheses even under a relatively high glucose loading. Although glyconeogenesis was inhibited in the metformin treated mice, it was not observed in JQ-R treated mice. Similar to metformin, JQ-R could also improve the glucose infusion rate (GIR) in hyperglycemic clamp test. JQ-R was also shown to increase the levels of phosphorylated AMPKα and phosphorylated acetyl CoA carboxylase (ACC), similar to metformin. Conclusion JQ-R could reduce HFD-induced insulin resistance by regulating glucose and lipid metabolism, increasing insulin sensitivity through activating the AMPK signaling pathway, and subsequently improving β cell function. Therefore, JQ-R may offer an alternative in treating disorders associated with insulin resistance, such as prediabetes and T2DM.