Phytochemical Characterization and Antidiabetic Evaluation of <i>Saurauia bracteosa</i> Leaf Extract in a Type 2 Diabetes Mellitus Model

Abstract

Background: Saurauia bracteosa is a medicinal plant traditionally used by the Batak Toba and Karo people of North Sumatra, Indonesia, as an antidiabetic agent. However, there is a lack of scientific evidence supporting its efficacy. Objectives: This study aimed to explore the potential of S. bracteosa leaf extract for treating type 2 diabetes mellitus (T2DM) based on an in vivo study. Methods: Phytochemical profiling of S. bracteosa extract was carried out by liquid chromatography high resolution mass spectrometry (LC-HR MS). Antidiabetic activity was tested toward the T2DM animal model induced with a combination of diet and streptozotocin for 30 days. The parameters were blood glucose, hemoglobin A1c (HbA1c), immunoreactive score of glucose transporter 4 (GLUT4) expression, diameters of islets of Langerhans, total cholesterol, and triglycerides. Results: LC-HR MS showed that the extract contains 22 compounds. The in vivo results showed that S. bracteosa extract significantly lowered blood glucose levels in the T2DM rat model (100, 200, and 400 mg/kg). Treatment with S. bracteosa extract at doses of 200 and 400 mg/kg significantly reduced HbA1c levels, increased the immunoreactive score of glucose transporter 4 (GLUT4) expression, and diameters of islets of Langerhans. Regarding the lipid profile, the extract, starting at a dose of 100 mg/kg, reduced total cholesterol levels, while only a 400 mg/kg extract dose could reduce triglyceride levels. Conclusions: The findings indicate that S. bracteosa leaf extract demonstrated antidiabetic effects in vivo by reducing blood glucose and HbA1c levels, enhancing GLUT4 expression, preserving islet morphology, and improving lipid profiles. These results support its potential as a plant-based therapeutic agent for managing type 2 diabetes mellitus.