Microwave-assisted extraction of bioactive alkaloids from Stephania sinica

• An MAE method was developed for the extraction of alkaloids from Stephania sinica.
• The MAE method is fast, energy-saving and environmental-friendly.
• An HPLC method was developed for the quantitation of the target alkaloids.
• The MAE–HPLC method is applicable to the analysis of the alkaloids in S. sinica.

A microwave-assisted extraction method was developed for the extraction of four bioactive alkaloids from Stephania sinica, and the quantification of the alkaloids was achieved by HPLC. The factors of major effects on the extraction were selected by single factor experiments, and the optimal levels of three main effective factors were obtained using the response surface method by employing Box–Behnken design. The optimal conditions for maximizing the extraction yields of the alkaloids were determined as follows: liquid-to-solid ratio 24:1 mL/g, ethanol concentration 65%, extraction time 90 s, temperature 60 °C, and microwave power 150 W. In comparison with the Soxhlet and ultrasonic-assisted extractions, the proposed method was fast, energy-saving and environmental-friendly.