Separation of five bioactive compounds from Glycyrrhiza uralensis Fisch using a general three-liquid-phase flotation followed by preparative high-performance liquid chromatography

Abstract

ABSTRACT Glycyrrhiza uralensis Fisch is homologous medicine for food plant and health-protective affection in the human body system. To further understand the functions of G. uralensis Fisch, separation of the bioactive compounds from this natural product is very important. A general three-liquid-phase flotation (TLPF) technique was established to separate and concentrate five bioactive compounds from G. uralensis Fisch. The three-liquid-phase system, pH of initial aqueous phase, (NH4)2SO4 concentration, nitrogen flow rate, and flotation time were investigated. The flotation efficiency of liquiritin apioside, liquiritin, and glycyrrhizic acid in the middle phase and semilicoisoflavone B and licoisoflavone B in the upper phase could reach 91.24%, 94.23%, 88.04%, 94.67%, and 96.44%, respectively. Furthermore, the established TLPF was used for separation of four kinds of anthraquinones from Cassiae Semen. The results showed that TLPF is feasible for separating the compounds with quite a different polarity from natural products. Abbreviations TLPF: Three-liquid-phase flotation; TLPS: Three-liquid-phase system; prep-HPLC: Preparative high-performance liquid chromatography; TLPE: Three-liquid-phase extraction; ATPF: Aqueous two-phase flotation.