Separation and Purification of Three Individual Catechins From Tea Polyphenol Mixture by CCC

Countercurrent chromatography (CCC) was applied to the separation and purification of three catechins, i.e., epigallocatechin-3-o-gallate (EGCG), gallocatechin-3-o-gallate (GCG), and epicatechin-3-o-gallate (ECG) from a polyphenol mixture. Analytical CCC was used to select suitable two-phase solvent systems from ethyl acetate-ethanol-water and hexane-ethyl acetate-water systems by adjusting mutual volume ratios in each system. Using the optimized solvent systems, the preparative separation was successfully performed by two-step separation where 1 g crude sample was efficiently purified, yielding 275 mg of EGCG, 140 mg of GCG, and 130 mg of ECG, each at high purity about 98% by HPLC analysis. The structures of these catechins were identified by FAB-MS, 1H, and 13C NMR.