Molecular Mechanisms and Antidiabetic Effects of Mango (Mangifera indica) Leaf Extract as a GLP-1 Analogue in Type 2 Diabetic Rats

Abstract

This study investigated the potential of scale-up mango leaf extract (MLE) as a treatment for diabetes, a global public health concern. MLE was prepared by boiling in water, yielding 12.07% (w/w), with a bioactive mangiferin content of 165.67 ± 10.88 μg/g in the crude powder. Mechanistically, MLE demonstrated a hypoglycemic effect by stimulating glucagon-like peptide-1 (GLP-1) secretion in NCI-H716 L-cells. This occurred through activation of the MAPK signaling pathway, evidenced by increased p-ERK1/2, p-p38, and p-c-Jun expression, and the Wnt signaling pathway, shown by increased β-catenin and decreased GSK-3β and Axin1 expression, consistent with molecular docking. In a type 2 diabetic rat model, MLE administration (40 mg/kg) significantly reduced metabolic parameters, including fasting blood glucose (FBG), body weight, cholesterol (CHOL), triglycerides (TGs), and HbA1c. Notably, MLE lowered serum insulin and the HOMA-IR index, and reduced serum dipeptidyl peptidase-IV (DPP-IV) levels, resulting in increased serum GLP-1, comparable to the drug sitagliptin. These findings suggest that MLE has great potential to lower blood glucose by inducing GLP-1 secretion via MAPKs and Wnt signaling pathways, positioning it as a promising candidate for alternative diabetes treatment or development as a dietary supplement.