Comparison of Different High-Speed Countercurrent Chromatography Injection Modes for the Separation of Glabridin.

In this work, different injection modes (single injection, overlapping injection, and continuous injection) of countercurrent chromatography were used and compared for the isolation and purification of glabridin from the crude extract of Glycyrrhiza glabra. The two-phase solvent system consisting of n-hexane/ethyl acetate/methanol/water (5:4:5:4, v/v) was employed as stationary and mobile phases. Compared with single injection mode, both overlapping injection and continuous injection modes exhibited higher separation efficiency at the same sample loading capacity. Their total separation times were 89.68% and 53.97% of the single injection mode, and the total solvent consumption were 74.88% and 52.49% of the single injection mode, respectively. Meanwhile, the yield, purity, and recovery rate of these three injection modes were almost the same. It was demonstrated that high-speed countercurrent chromatography in continuous injection mode was the most effective way for separating glabridin in three methods and it can be further applied to the separation of other economically valuable natural products.