One-step purification of epigallocatechin gallate from crude green tea extracts by isocratic hydrogen bond adsorption chromatography on β-cyclodextrin substituted agarose gel media

An oligomerized β-cyclodextrin ligand coupled to brominated allyl-group substituted Sepharose HP has been used for the one-step purification of polyphenolic epigallocatechin gallate (EGCG), an important antioxidant, by isocratic hydrogen bond adsorption chromatography. With a sample load of 1.33 mg crude green tea polyphenolic extract per ml column packing and with water/ethanol/acetonitrile (57/30/13, v/v) as the optimum mobile phase, an EGCG purity of about 98% with a recovery of approximate 73% could be achieved by proper peak cutting. After about 10 sample applications, the column performance started to deteriorate but could be regenerated to its original function by cleaning with 0.35 M NaOH.