The Chinese formula Tang-Min-Ling (TML), an improved product of the decoction of Dachaihu which has a history of more than 2000 years, has main constituents of Coptis chinensis Franch, Scutellaria baicalensis Georgi, Rheum officinale Baill and Bupleurum chinense DC. A multi-central randomized controlled investigation performed previously by us has showed that TML has positive effects on regulating glycometabolism in type 2 diabetes (T2DM) patients, but the mechanisms remain unclear. Using Otsuka Long-Evans Tokushima Fatty (OLETF) rats as an animal model with rosiglitazone as a positive control, we were able to detect TML's effect on the serum glucose, serum lipid, serum leptin and adiponcetin after oral administration for 12 weeks. We were also able to detect the insulin resistance level by a glucose clamp test and study the mechanisms of TML in improving insulin resistance by detecting skeletal muscle AMP-activated protein kinase (AMPK) and glucose transporter 4 (GLUT4). Results showed that TML significantly reduced the glucose area under a curve of the oral glucose tolerance test, and had a positive effect in regulating serum lipid metabolism. TML treatment also significantly reduced the serum leptin level, but it had no effect on the serum adiponectin level. The AMPK enzymatic activity and GLUT4 expression in Skeletal Muscle were also upregulated in the TML group. The results suggest that the Chinese medicine TML, which contains Coptis chinensis Franch as one of its components, improves glycometabolism and its possible mechanisms may involve in improvement of insulin resistance of OLETF rats.

Diabetes mellitus (DM), a kind of metabolic disease, is increasing over the last four decades in the world. The purpose of this study was to investigate the effect of Jiang Tang Xiao Ke (JTXK) granule, a naturally occurring ingredient from Chinese herbal medicines, on serum glucose, lipids, and oxidative stress in DM rats induced by high-fat diet and streptozotocin. JTXK granule 9 g/kg (based on crude herb equivalent) and pioglitazone 1.5 mg/kg (as a positive control for comparison) were orally administrated to DM rats for 4 weeks. Results showed that administration of JTXK granule reduced serum glucose, total cholesterol, triglyceride, and low density lipoprotein levels (by 12%, 33%, 57%, and 44%, resp.) but increased high-density lipoprotein level by 69%, compared with the drug-untreated DM rats. Serum malondialdehyde and nitric oxide levels were lowered (by 34% and 52%, resp.) associated with the elevation in serum superoxide dismutase levels (by 60%) after JTXK granule treatment. In addition, JTXK granule suppressed serum alanine aminotransferase activity (up to 50%) and alleviated pathological changes of pancreas and liver tissues in DM rats. The beneficial changes of pioglitazone on biomarkers were also found in DM rats. These findings suggested that JTXK granule may be an alternative medicine for the management of DM.

In this study, we investigated the effects of a Chinese herbal medicine formula xiao-gao-jiang-zhuo (XGJZ) in obese rats induced by a high-fat diet. Ten male rats in the normal group were fed with a standard diet. Another 50 male obese rats were induced by a 12-week high-fat diet feeding, and were randomly divided into five groups (n = 10 per group): the model group, the high-dose XGJZ group, the middle-dose XGJZ group, the low-dose XGJZ group, and the sibutramine group. After 14 weeks of treatment, body weight, abdominal fat, blood lipid and serum insulin level were measured, and the protein and gene expression of PTP1B in liver tissue was tested. Our data showed that the body weight of the high-dose and middle-dose groups and the sibutramine group had significant differences in comparison with the model group (p < 0.05), and all three dose groups had significantly reduced abdominal fat (p < 0.05). The triglyceride level of the three dose groups and the sibutramine group, and the total cholesterol level of the middle-dose group were all significantly reduced (p < 0.05). The serum insulin of the high-dose and middle-dose groups also decreased significantly (p < 0.05). The expression of hepatic PTP1B mRNA of the three dose groups decreased significantly in comparison with the model group (p < 0.05 or 0.01). The expression of hepatic PTP1B protein of the high-dose and middle-dose groups decreased significantly (p < 0.05). Our data suggested that XGJZ can modulate the body weight, abdominal fat and blood lipid in the obese rats, and this modulation might improve insulin resistance by inhibiting the PTP1B signal pathway.