Separation-and purification of three individual catechins from tea polyphenol mixture by CCC

Countercurrent chromatography (CCC) was applied to the separation and purif ication of three catechins, i.e., epigallocatechin-3-o-gallate (EGCG), gall ocatechin-3-o-gallate (GCG), and epicatechin-3-o-gallate (ECG) from a polyp henol mixture. Analytical CCC was used to select suitable two-phase solvent systems from ethyl acetate-ethanol-water and hexane-ethyl acetate-water Sy stems 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, yieldi ng 275 mg of EGCG, 140 mg of GCG, and 130 ing of ECG, each at high purity a bout 98% by HPLC analysis. The structures of these catechins were identifie d by FAB-MS, 1 H, and C-13 NMR.