Preparative separation of quaternary ammonium alkaloids from Coptis chinensis Franch by pH-zone-refining counter-current chromatography

pH-zone-refining counter-current chromatography was successfully applied to the preparative separation of five quaternary ammonium alkaloids from the crude extract of Coptis chinensis Franch. The separation was performed with a two-phase solvent system composed of chloroform-methanol-water (4:3:3, v/v), where the upper aqueous stationary phase was added with 60 mM of hydrochloric acid and the lower organic mobile phase with 5 mM of triethylamine. From 1.0 g of crude extract, 5.4 mg of columbamine at 96.6% purity, 6.1 mg of jateorhizine at 98.8% purity, 58.3 mg of coptisine at 99.5% purity, 25.6 mg of palmatine at 98.4% purity and 503.9 mg of berberine at 99.5% purity were obtained. The purities of the isolated alkaloids were analyzed by HPLC and the chemical structures were identified by electrospray ionization-mass spectrometry and 1H NMR.