Isolation and purification of alkaloids from the fruits of Macleaya cordata by ionic-liquid-modified high-speed counter-current chromatography

Macleaya cordata (Willd) R. Br. is a medicinal plant. The most important bioactive compounds of M. cordata are alkaloids that have many biological activities including antifungal, anti-inflammatory, and antitumor. In this study, an ionic-liquid-modified high-speed counter-current chromatography method was established to obtain alkaloids from the fruits of M. cordata. The conditions of ionic-liquid-modified high-speed counter-current chromatography, including solvent systems, the content of ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [C(4)mim][BF4]), and the posttreatment of the ionic liquid, were investigated. Five alkaloids protopine, allocryptopine, sanguinarine, 8-O-demethylchelerythrine, and chelerythrine were separated from the extract of the fruits using a high speed counter-current chromatography with two-phase solvent system composed of dichloromethane/methanol/0.3 mol/L hydrochloric acid aqueous solution/[C(4)mim][BF4] (4:2:2:0.015, v/v). Their purities were 96.33, 95.56, 97.94, 96.22, and 97.90%, respectively. The results indicated that a small amount of ionic liquids as modifier of the two-phase solvent system could shorten the separation time and improve the separation efficiency of the alkaloids from the fruits. The ionic-liquid-modified high-speed counter-current chromatography would provide a feasible way for highly effective separation of alkaloids from natural products.