Single‐Step Preparative Isolation and Separation of Three Flavonones from Sophora flavescens using High‐Speed Countercurrent Chromatography with Stepwise Increase in the Mobile Phase Flow Rate

Abstract

Abstract Three flavonoids, including sophoraflavanone G (SFG), kushenol I, and kurarinone were isolated and separated by high‐speed countercurrent chromatography (HSCCC) from Sophora flavescens, a traditional Chinese medicinal herb. Preparative HSCCC with a two‐phase solvent system composed of n‐hexane–ethyl acetate–methanol–water at the volume ratio of 1:1:1:1 (v/v/v/v) was successfully performed by increasing the flow rate of the mobile phase from 1.0 mL/min to 2.0 mL/min after 120 min. The total isolation produced 22.5 mg SFG, 39.3 mg kushenol I and 83.5 mg kurarinone from 350 mg crude extract (containing SFG 6.7%, kushenol I 11.9%, kurarinone 25.7%) in one‐step isolation with purities of 95.6%, 97.3%, and 99.4%, respectively, as determined by high performance liquid chromatography (HPLC), and the recoveries of the targets were 91.7%, 91.8%, and 92.3%, respectively. The chemical structural identification was performed by UV, IR, MS, 1H NMR, and 13C NMR.