Preparative separation of alkaloids from Nelumbo nucifera Gaertn by pH‐zone‐refining counter‐current chromatography

Preparative separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn has been successfully performed for the first time using pH-zone-refining counter-current chromatography. Two kinds of two-phase solvent systems were applied to preparative CCC isolation. The first was the system composed of MtBE-water (1:1, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which could only separate neferine partly from the crude extract. The second was the system composed of n-hexane-ethyl acetate-methanol-water (5:5:2:8, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which was the optimum for large-scale CCC isolation. 2.5 g of the crude alkaloid was purified in one-step separation of 7 h, yielding 151 mg of liensinine, 118 mg of isoliensinine and 572 mg of neferine with the purities of 93.0, 95.1 and 97.0%, respectively.