Microwave-assisted Extraction of Rutin and Quercetin from the Stalks of Euonymus alatus (Thunb.) Sieb

Introduction - Euonymus alatus (Thunb.) Sieb has been used as one of traditional Chinese medicines for several thousand years. Conventional methods for the extraction of rutin and quercetin from E. alatus, including solvent extraction, Soxhlet extraction and heat reflux extraction are characterised by long extraction times and consumption of large amounts of solvents. Objective - To develop a simple and rapid method for the extraction of rutin and quercetin from the stalks of Euonymus alatus (Thunb.) Sieb using microwave-assisted extraction (MAE) technique. Methodology - MAE experiments were performed with a multimode microwave extraction system. The experimental variables that affect the MAE process, such as the concentration of ethanol solution, extractant volume, microwave power and extraction time were optimised. Yields were determined by HPLC. The results were compared with that obtained by classical Soxhlet and ultrasonic-assisted extraction (UAE). Results - From the optimised conditions for MAE of rutin and quercetin it can be concluded that the solvent is 50% ethanol (v/v) solution, the extractant volume is 40 mL, microwave power is 170 W and irradiation time is 6 min. Compared with Soxhlet extraction and ultrasonic extraction, microwave extraction is a rapid method with a higher yield and lower solvent consumption. Conclusion - The results showed that MAE can be used as an efficient and rapid method for the extraction of the active components from plants. Copyright (C) 2008 John Wiley & Sons, Ltd.