Separation of Catechin Compounds from Korean Green Tea

초록

Recently, the demand on the green tea has increased due to the concern on the health. Although its chemical composition varies with growing conditions, the principal catechin compounds included in green tea are (-) epicatechin (EC), (-)epigallocatechin (EGC), (-)epicatechin gallate (ECG), (-) epigallocatechin gallate (EGCG) and (+)catechin (C). These catechin compounds have been reported a variety of efficiency that dementia prevention, AIDS virus inhibition and environment hormone inhibition. Among these catechin compounds, EGCG has the strongest cancer preventive activities. The purpose of this work is to set up the procedures for separating purely EGCG from the green tea. The green tea used in this experiment was cultivated at Bosung (Chonman, Korea). By HPLC-analysis, the content of EGCG was 121.3mg/5g of dry green tea. First the powder of green tea was extracted by warm water (50℃) and the extract was partitioned with chloroform and ethyl acetate. The resulting solution was further purified by chromatographic column of two packings, 40-63 and 15㎛. Finally chromatographic separation was achieved on a commercially available -Bondapak C18 column. The elution orders of the catechin compounds were EGC, C, EC, EGCG and ECG. The mobile phase for isolating EGCG from the extract consisted of 0.1% acetic acid in water/acetonitrile, 87/13 vol.%. The separated amount of EGCG was 15.8㎍ with 98% of purity in a single run.