Separation and purification of isofraxidin from Sarcandra glabra by microwave-assisted extraction coupled with high-speed counter-current chromatography

In this paper, a simple method based upon microwave-assisted extraction (MAE) coupled with highspeed counter-current chromatography (HSCCC) for the rapid isolation, separation and purification of isofraxidin from Sarcandra glabra (thunb.) was developed. The dry extract obtained from MAE was directly introduced into the HSCCC for separation and purification. The critical experimental parameters of MAE and HSCCC were optimized. 2 g of Sarcandra glabra sample was extracted with 20 mL 60% (v/v) ethanol aqueous at 65 degrees C for 20 min at 500 W of microwave irradiation, then the extracting solution was concentrated to 300 mg dry extract. The dry extract was dissolved with the lower phase of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v/v/v), separated and purified by preparative HSCCC. 300 mg dry extract can be introduced into the HSCCC system in one-step and 1.20 mg of isofraxidin was obtained with purity over 99% in 2.5 h. The purity of isofraxidin was determined with HPLC and its chemical structure was identified with H-1 NMR. The results indicate that the method is simple, fast and efficient. The method has good potential on the separation and purification of effective compounds from natural product. (C) 2009 Elsevier B.V. All rights reserved.