Dose-dependent effects, safety and tolerability of fenugreek in diet-induced metabolic disorders in rats

Background: We previously reported that fenugreek (Trigonella foenum-graecum L.) improved diet-induced metabolic disorders in rats. The purpose of the present study was to examine the dose-dependent effects, safety and tolerability of fenugreek. Methods: The diets used in this study were the high-fat high-sucrose diet (HFS; lard 50% kcal, sucrose 25% kcal) as a control (Ctrl group) or the HFS containing 0.25% (VL group), 1.25% (L group), 2.50% (M group), 5.00% (H group) or 12.30% (VH group) fenugreek based on the modified version of the AIN-93G purified diet. Results: Fenugreek dose-dependently reduced the hepatic triglyceride and total cholesterol levels. Fenugreek also dose-dependently increased the excretion of cholesterol and total bile acids into the feces. However, the glucose tolerance showed no significant change by fenugreek administration. The VL and L groups did not significantly change triglyceride or total cholesterol levels in the liver. The VL group showed no increase in excretion of triglyceride, total cholesterol or bile acids in the feces. The VH group showed appetite reduction and diarrhea, while no adverse effect or symptoms were observed in the M group. Conclusion: These results suggest that fenugreek inhibited lipid accumulation in the liver by increasing the lipid excretion in the feces. The effective, safe and tolerable dose of fenugreek was found to be around 2.50% (w/w).