Separation of Alkaloids from Corydalis Decumbens (Thunb.) Pers.by High Speed Counter-Current Chromatography
A method was established for the separation and purification of alkaloids from the crude extract of Corydalis decumbens(Thunb.) Pers. using high speed counter-current chromatography(HSCCC) with two modes. First, pH-zone-refining counter-current chromatography was successfully performed with a two-phase solvent system, n-hexane-ethyl acetate-methanol-water(5∶5∶2∶8, V/V), in which 5 mmol/L triethylamine in the organic stationary phase and 5 mmol/L hydrochloric acid in the aqueous mobile phase. From 3.0 g of crude extract, a mixture and three compounds, with 375 mg protopine(1), 362 mg humosine A(2) and 246 mg bicuculline(3) were obtained with purities of 97.5%, 95.6% and 97.1%, respectively. And then, the mixture was separated by HSCCC with the two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water(1∶0.8∶1.1∶1, V/V). Bicuculline(105 mg) and tetrahydropalmatine(470 mg) were obtained from 850 mg mixture. Among them, humosine A was isolated from Corydalis decumbens(Thunb.) Pers. for the first time. pH-Zone refining counter-current chromatography combined with routine HSCCC improved the separation efficiency of alkaloids from crude Corydalis decumbens(Thunb.) Pers.