Optimization of Verbascoside Extraction from Jasminum subtriplinerve Blume Collected in Quang Tri Province Using Response Surface Methodology

This study optimized the ultrasound-assisted extraction of verbascoside from Jasminum subtriplinerve Blume using an ethanol–water solvent system. Verbascoside content under various conditions was determined by HPTLC- Scanning. Key variables and their ranges were initially screened using the one-factor-at-a-time approach and subsequently optimized via response surface methodology with a Box–Behnken design. Ethanol concentration (10–40%), extraction temperature (50–80°C), and extraction time (15–45 min) were selected as independent variables, while verbascoside yield and total extract yield were responses. Under the optimal conditions (33% ethanol, 76°C, 43 min), the verbascoside yield reached 60.12% and total extract yield was 24.46%, with RSD values of 1.77% and 1.49%, respectively. This result provides a scientific basis for the production of a highly concentrated extract of verbascoside from the medicinal plant, opening up applications in medicine and pharmaceuticals.