Effective and Preparative Separation of Bioactive Flavonoids FromGynostemma PentaphyllumTea Using Elution-Extrusion Counter-Current Chromatography

Abstract Elution-extrusion counter-current chromatography (EECCC) was successfully applied for screen and separation of four flavonoids from Gynostemma pentaphyllum tea, a popular herbal tea extract in China. With the hexane/ethyl acetate/methanol/water 5/6/5/6 (v/v) system, 300 mg of G. pentaphyllum tea extract were fractionated on a 180 mL-capacity preparative hydrodynamic CCC column. Satisfactory separation efficiency was achieved, producing milligram-amounts of quercetin, isorhamnetin, and cirsiliol over 90% pure in one EECCC process. Due to the hydrophilic property, the major flavonoid glycoside, rutin, was co-eluted with the solvent front as a mixture. Therefore, another carefully selected biphasic liquid system composed of ethyl acetate/n-butanol/water (4/1/5, v/v) was employed, yielding 35 mg of rutin with 97.1% purity. Structures of all separated compounds were identified by ESI-MS, 1H NMR, and 13C NMR. Keywords: counter-current chromatographyelution-extrusionflavonoids gynostemma pentaphyllum preparative chromatography ACKNOWLEDGEMENTS Financial support from the Project of Zhejiang Key Scientific and Technological Innovation Team (No. 2010R50039), the National Natural Science Foundation (No. 31070298, 30870180, 21005072), the Zhejiang Scientific and Technological Program (No. 2008C12081, 2010C12016), and the Hangzhou Scientific and Technological Program (No. 20101032B25) are gratefully acknowledged.