Studies On The Separation And Purification Of High Content Tea Catechins EGCG And ECG

Tea catechins are the important ingredients in green teas. Due to their widespread biological activity, antioxidant ability and the capability to remove free radicals, more and more importance are attached to them. Currently there are main eight kinds of catechins monomers that have been identified and they can be divided into two groups, one is ester type and the other is non-ester type. The most useful and demanded monomers are two ester type monomers-EGCG and ECG .Raw TP was employed as material and orthogonal experiment method was used to systematically study the preseparation and purification conditions of EGCG and ECG by gel chromatography. Took Sephadex LH-20 as stuffing with the height of 50 cm and ethanol as elution agent with the elution speed of 0.75ml/min in the preseparation process, we effectively separated EGCG (including GCG) and ECG For ECG, the elution rate was 97.64% and the rate of purity was 97.62%, abstract rate was 85.67%; for EGCG, the elution ratio was 98.45% and the rate of purity was 88.66%. The EGCG (including GCG) fraction obtained in the preseparation process was properly enriched and employed as raw stuff in purification process. After purification process also carried out by Sephadex LH-20 with the height of 50cm under the condition of 40% ethanol as elution agent with the elution speed of 0.60ml/min, high-purity EGCG monomers were obtained (the chromatogram purity of obtained EGCG monomers was above 99%) and the elution rate was above 98%, abstract rate was 85.31% . Continuous operations of preseparation process and purification process were achieved by this method and it was easily manipulated. Besides, it needed low cost, produced no poisons and had high extraction rate and purity. Moreover, the preparation achieved gram magnitude for once time. Their molecular structure were identified or verfied by UV, IR, LC-MS, H-NMR instrumental techniques.In addition, elementary conclusion for the mechanism of the separation process of catechins with Sephadex LH-20 was obtained that the separation was achieved by the combined action of molecular filter effects, adsorption effects and distributional effects.