Preparation of flavonoids and diarylheptanoid from Alpinia katsumadai hayata by microwave-assisted extraction and high-speed counter-current chromatography

Abstract

In the present work, five flavonoids and diarylheptanoid, namely, alpinetin, pinocembrin chalcone, pinocembrin, cardamomin and 1,7-diphenyl-4,6-heptadien-3-one, were simply and rapidly prepared from Alpinia katsumadai hayata ( A. katsumadai) by microwave-assisted extraction (MAE) followed with high-speed counter-current chromatography (HSCCC). The critical conditions of MAE and HSCCC were optimized. 2.0 g crude sample was extracted with MAE, and then directly separated and purified by HSCCC with a two-phase solvent system composed of hexane–ethyl acetate–methanol–water (3:7:6:4, v/v/v/v), and 7.5 mg of alpinetin, 1.9 mg of pinocembrin chalcone, 2.6 mg of 1,7-diphenyl-4,6-heptadien-3-one with purities of 98.3%, 96.9% and 93.0% were obtained respectively in a single step within 4 h. 4.0 mg mixture of cardamomin and pinocembrin from HSCCC was further separated by prep-HPLC, 2.1 mg of 99.4% pinocembrin and 1.4 mg of 99.8% cardamomin were obtained respectively. The purities of compounds were determined by HPLC and their chemical structures were further identified by ESI-MS and 1H NMR. The results demonstrated that MAE coupled with HSCCC was a feasible, economical and efficient technique for rapid extraction, separation and purification of effective compounds in natural products.