A rapid chromatographic method for separation of individual catechins from green tea

Catechins from Chinese green tea were extracted into hot water and were partially purified using a counter-current chromatographic procedure. Solvent systems employed were water/chloroform (1:1, v/v) and water/ethyl acetate (1:1, v/v). Crude catechins so obtained were subjected to Sephadex LH-20 column chromatography using ethanol as the solvent. Eluate fractions, as such, were analyzed by measuring their absorbances at 280 nm, and at 500 nm after colour development reactions for catechins. Separated fractions by column chromatography were also monitored using silica gel thin layer chromatographic plates. Sephadex LH-20 provided a rapid method for separation of (-)epicatechin, (-)epigallocatechin, (-)epicatechin-3-gallate and (-)epigallocatechin-3-gallate. Semi-preparative high performance liquid chromatography on RP-18 column with a water/acetonitrile/methanol/acetic acid (79.5:18:2:0.5, v/v/v/v) mobile phase successfully separated individual catechins from other phenolics. Chemical structures of purified catechins were further confirmed by H-1-NMR spectroscopy. Copyright (C) 1996 Canadian Institute of Food Science and Technology