Separation and Purification of Epigallocatechin Gallate and Epicatechin Gallate by Two-step Chromatography Involving _-cyclodextrin Bonded Agar.

A novel method was developed to separate the tea polyphenols epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) by two-step chromatography. In the first-step, four different macroporous absorption resins were compared by dynamic desorption, of which only AB-8 resin resulted in enriched fractions for EGCG and ECG. Their purity was 53.69 %, and 65.77 %, with recovery rates of 88.05 %, and 83.46 %, respectively. For the second-step, The recovery rates of 85.36 % and 86.09 % for EGCG and ECG were obtained respectively by a novel stationary phase of ß-CD bonded agar gel. The overall recovery efficiency of the complete procedure was 75.16 % for EGCG and 71.85 % for ECG, respectively, and the purity of the obtained preparations reached 97.63 % for EGCG and 98.09 % for ECG. The chromatographic behavior of ß-cyclodextrin bonded agar gel was studied with elution by acetonitrile, which indicated that both hydrophilic and hydrophobic interactions between the polyphenols and the solid phase occurred. [ABSTRACT FROM AUTHOR]