Preparative Separation and Purification of Liquiritin and Glycyrrhizic Acid from Glycyrrhiza uralensis Fisch by High-Speed Countercurrent Chromatography

The technique of high-speed countercurrent chromatography (HSCCC) was applied to the preparative isolation and purification of liquiritin and glycyrrhizic acid from a crude extract of Glycyrrhiza uralensis Fisch for the first time. Using single factor and orthogonal design experiments, the best extraction conditions were 70% ethanol, 1:25 ratio of solid-to-liquid (w/v) and extracted 1.5 h at 80°C. The contents of liquiritin and glycyrrhizic acid in the crude extract were 1.3 and 5.3%, respectively. Using the two-phase solvent system of ethyl acetate–methanol–water (5:2:5, v/v), 6.0 mg liquiritin (the purity was 96.7%, and the recovery was 89.3%), and 20.5 mg glycyrrhizic acid (the purity was 98.9%, and the recovery was 77.1%) were obtained from 500 mg crude extraction by HSCCC, respectively. The retention rate of stationary phase was 51.0%. Their structures were identified by high-performance liquid chromatography, melting points, ultraviolet radiation, Fourier transform infrared (FTIR), Electrospray ionization mass spectrometry (ESI-MS), 1H Nuclear Magnetic Resonance (NMR) and 13C NMR spectra. The scavenging abilities of glycyrrhizic acid to 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radicals were stronger than those of liquiritin.