Safety and anti-diabetic efficacy of a novel, proprietary Trigonella foenum-graecum seed extract [novel fenugreek extract (FE), Fenfuro™, CR0010810) enriched in furostanolic saponins (>60% w/w, HPLC) were assessed. Concerning safety, we undertook studies dealing with acute oral toxicity, 28-d sub-chronic toxicity and Ames' bacterial reverse mutation assay that revealed no toxicity. Concerning efficacy, we examined beneficial effects of the extract on rats with type 2 diabetes (T2D). Male Sprague-Dawley rats received a high-fat diet for 2 weeks followed by streptozotocin (STZ, 35 mg/kg i.p.) to produce T2D. Seven days post-STZ, rats showing ≥300 mg/dl fasting plasma glucose level (PGL) were included in the study. FE (150- or 450- mg/kg p.o.) and glipizide (5 mg/kg p.o.) were administered once daily for 20 d and then twice daily for another 10 d (total 30 d). Blood samples were collected at 0, 10, 20 and 30 d of treatment and estimated for fasting plasma triglyceride (PTG), total cholesterol and insulin levels. After 30 d, FE and glipizide-treated diabetic animals were treated in combination with or without metformin (100 mg/kg) twice daily for another 10 d. FE did not influence body weight, feed and water intake. FE (150 mg/kg p.o.) reduced PTG levels in T2D rats by 22%, 24.6% and 29% at 10, 20 and 30 d of treatment, respectively, while glipizide (5 mg/kg p.o.) reduced the PTG levels by 57.4%, 46.2% and 39.4% at these time points. FE (450 mg/kg) treatment in STZ-induced diabetic rats produced significant hypoglycemic activity (approximately 31.5%) as compared to insulin (48.2% with 1 U/kg i.p.). FE (150 mg/kg p.o.) and metformin (100 mg/kg p.o.) combined produced significant reduction (20.7%) of PGL in T2D rats. No adverse effects were observed. We conclude after extensive in vitro and in vivo safety and efficacy studies that FE is safe and effective in treating T2D.
Keywords: 28-d sub-chronic toxicity; Ames’ bacterial reverse mutation assay; Fenfuro (FE); acute oral toxicity; animals; glipizide; metformin; type 2 diabetes.