Investigating the mechanism of cornel iridoid glycosides on type 2 diabetes mellitus using serum and urine metabolites in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Cornel iridoid glycosides (CIG) are extracted from Corni fructus, a herbal medicine used in traditional Chinese medicine to treat diabetes. However, the antidiabetic effects of CIG and the underlying metabolic mechanisms require further exploration. AIM OF THE STUDY: This study aimed to assess the antidiabetic effects and metabolic mechanism of CIG by performing metabolomic analyses of serum and urine samples of rats. MATERIALS AND METHODS: A rat model of type 2 diabetes mellitus (T2DM) was established by administering a low dose of streptozotocin (30 mg/kg) intraperitoneally after 4 weeks of feeding a high-fat diet. The model was evaluated based on several parameters, including fasting blood glucose (FBG), random blood glucose (RBG), urine volume, liver index, body weight, histopathological sections, and serum biochemical parameters. Subsequently, serum and urine metabolomics were analyzed using ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS). Data were analyzed using unsupervised principal component analysis (PCA) and supervised orthogonal partial least squares discriminant analysis (OPLS-DA). Differential metabolites were examined by the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways to explore the underlying mechanisms. RESULTS: After 4 weeks of treatment with different doses of CIG, varying degrees of antidiabetic effects were observed, along with reduced liver and pancreatic injury, and improved oxidative stress levels. Compared with the T2DM group, 19 and 23 differential metabolites were detected in the serum and urine of the CIG treatment group, respectively. The key metabolites involved in pathway regulation include taurine, chenodeoxycholic acid, glycocholic acid, and L-tyrosine in the serum and glycine, hippuric acid, phenylacetylglycine, citric acid, and D-glucuronic acid in the urine, which are related to lipid, amino acid, energy, and carbohydrate metabolism. CONCLUSIONS: This study confirmed the antidiabetic effects of CIG and revealed that CIG effectively controlled metabolic disorders in T2DM rats. This seems to be meaningful for the clinical application of CIG, and can benefit further studies on CIG mechanism.

[Studies on anti-hyperglycemic effect and its mechanism of Clinopodium chinense].

OBJECTIVE: To investigate the anti-hyperglycemic effect and its mechanism of ethanol extraction from Calamintha chinensis (EJCT). METHOD: Fasting serum glucose (FSG) in normal mice was determined after oral administration of EJCT. Effects of EJCT on hyperglycemia mice induced by adrenaline were investigated by observing the contents of FSG and liver glucogen. Effect of EJCT on the diabetic mice induced by alloxan was investigated by observing the contents of FSG and the injured degree of pancreatic islet. The antilipid-peroxidation of EJCT on liver homogenate was measured by determination of malondiadehyde (MDA) induced by Fe2+/Cys. RESULT: EJCT showed no obvious effect on FSG in normal mice. However, EJCT 300, 600 mg x kg(-1) could remarkably decrease the contents of FSG and increase liver glucogen in hyperglycemia mice induced by adrenaline. In diabetic mice induced by alloxan, EJCT 150, 300, 600 mg x kg(-1) could remarkably decrease the contents of FSG. The damage of pancreatic islet induced by alloxan was also significantly attenuated by EJCT. Furthermore, EJCT 30, 60, 90, 120 mg x L(-1) inhibited lipid peroxidation initiated by Fe2+/Cys in liver homogenate. CONCLUSION: These results suggest that EJCT can significantly attenuate hyperglycemia in diabetic mice, which is probably due to decreasing the decomposition of liver glucogen, increasing the synthesis of liver glucogen, antioxidation and amelioration of damaged pancreatic islet.