A structured multi-day experimental framework integrating green chemistry for the extraction and characterization of Berberine hydrochloride in undergraduate education

To address the challenges of complex workflows, limited student engagement, and insufficient integration of green and interdisciplinary skills in traditional laboratory teaching, this study introduces a multi-day experimental teaching framework with a staged instructional design for the extraction, purification, and identification of berberine hydrochloride (BH) in undergraduate natural product chemistry courses. The framework is implemented as a multi-day practical, pedagogically organized into three instructional stages (extraction, separation and purification, and identification), each of which is aligned with specific learning objectives. This stage-based instructional structure reduces cognitive load and enhances learning outcomes. Green chemistry principles were incorporated into the G-RPWAM (green-reagents, procedures, waste, awareness, methodology) framework to guide solvent selection and procedural design, optimize reagent use, minimize waste, and reduce energy consumption in undergraduate laboratory teaching while fostering environmental awareness. A comprehensive evaluation system, including technical metrics (extraction yield, purity), student performance (experimental skills, data analysis ability, creative thinking, problem-solving ability), and student feedback (content clarity, structured organization, green principles integration, overall effectiveness), was employed to assess the teaching innovation. The results demonstrated that the staged instructional design improved the accessibility and scalability of the experiment, enhanced student satisfaction, and successfully cultivated both sustainability awareness and laboratory skills. This study provides a structured, pedagogy-oriented approach aligned with green chemistry principles for undergraduate natural product chemistry education.