A Bioactive Fraction of Euphorbia antiquorum Stem Powder Ameliorates High-Fat High-Fructose Diet/Streptozotocin-Induced Diabetes via GLUT-4 Modulation.

Euphorbia antiquorum L. (Euphorbiaceae), a traditionally used Asian medicinal plant, was systematically evaluated for its antidiabetic efficacy through a bioactivity-guided approach integrating in vitro, in vivo, and in silico studies. Among the four solvent fractions of the ethanolic stem extract, the ethyl acetate fraction exhibited the highest antioxidant and glucose utilization activity. Column chromatography of the ethyl acetate fraction yielded several subfractions, among which Fraction 2 (CEA2) showed strong antioxidant activity and significantly enhanced glucose utilization and GLUT4 translocation (p < 0.01). In a 63-day high-fat high-fructose diet and low-dose streptozotocin-induced diabetic rat model, CEA2 (200 and 400 mg/kg) markedly reduced fasting blood glucose, improved body weight, restored biochemical parameters, and decreased TNF-α and IL-6 levels, while also improving pancreatic and hepatic histopathology. Western blotting confirmed significant upregulation of plasma membrane GLUT4 (p < 0.01). LC-MS profiling identified major compounds, including 3-O-trans-p-coumaroyltormentic acid and geranyl acetoacetate, which demonstrated strong binding to IRS-1 and Akt-PKB in docking and molecular dynamics analyses, key regulators of GLUT4 vesicle mobilization. This study provides one of the first comprehensive validations establishing CEA2 as a potent modulator of insulin signaling and GLUT4 mobilization, supporting E. antiquorum as a promising phytopharmaceutical candidate for type 2 diabetes management.