Antidiabetic, antihyperlipidemic and immunomodulatory effects of <i>Trigonella foenum</i> - <i>graecum</i> extract in streptozotocin-induced diabetic rats

Objectives: The objective of this study was to investigate the antidiabetic, lipid-lowering and immunomodulatory effects of ethanolic extract of Trigonella foenum-graecum (TFE) in streptozotocin (STZ)-induced diabetic rats fed a high-fat diet (HFD), with metformin serving as the reference standard. Materials and Methods: Thirty-six male Wistar rats were randomly allocated into six groups ( n = 6 each). Type 2 diabetes was induced by feeding a HFD followed by a single intraperitoneal dose of STZ (40 mg/kg). The diabetic animals were treated once daily for 21 days with either TFE extract (200, 500, or 1000 mg/kg, orally) or metformin (100 mg/kg, orally). Fasting blood glucose (FBS), serum lipid profile, body weight and resistin concentrations were assessed at baseline, week 5 and week 8. Statistical evaluation was carried out using one-way analysis of variance with appropriate post hoc analysis. Results: Administration of TFE extract led to a dose-dependent decline in fasting glucose and serum resistin, with the 1000 mg/kg dose showing highly significant improvement ( P &lt; 0.001), comparable to metformin. Treated groups also exhibited favourable changes in lipid profile, with reductions in total cholesterol, triglycerides, low-density lipoprotein (LDL) and very LDL, alongside a significant rise in high-density lipoprotein. Furthermore, the weight loss observed in diabetic controls was attenuated in animals receiving TFE or metformin. Conclusion: TFE extract markedly enhanced glycaemic regulation, corrected lipid disturbances and reduced systemic inflammation in diabetic rats. These actions are likely mediated by bioactive constituents such as trigonelline and 4-hydroxyisoleucine, supporting its promise as a safe, plant-based adjunct in the management of type 2 diabetes.