Garcinia Biflavonoid 1 from Garcinia kola Ameliorates Glycolipid Metabolism Disorder in Type 2 Diabetic db/db Mice

Background: Garcinia kola is recommended in African folk medicine for the treatment of diabetes and its associated complications. In this study, we investigated the effects of Garcinia biflavonoid 1 (GB1), an active chemical component of Garcinia kola, on blood glucose and lipid in db/db mice with type 2 diabetes. Methods: Db/db mice were divided into 4 groups: vehicle, low-dose GB1 (50 mg/kg), high-dose GB1 (100 mg/kg), and rosiglitazone, and treated for 4 weeks. Body weight, fasting blood glucose (FBG), fasting insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), hepatic glycogen, serum and liver biochemical parameters, and histological morphology of the pancreas, heart, and kidneys were evaluated. Results: GB1 significantly reduced FBG, the area under the curve value of OGTT and ITT, and the homeostasis model assessment of insulin resistance, increased the homeostasis model assessment of beta-cell function, quantitative insulin sensitivity check index, and the level of hepatic glycogen. Lower triglyceride and free fatty acid level, and a lower triglyceride-glucose index were also observed in the GB1 groups. In addition, no significant changes in alanine aminotransferase and aspartate aminotransferase levels, or in the histopathology of the pancreas, heart, or kidney were observed after GB1 treatment. Conclusion: These findings indicate that GB1 exerts an antidiabetic effect in db/db mice, by improving hyperglycemia, insulin resistance, and lipid dysregulation without evidence of adverse reactions.