| Tea is dry product of the tender leaf of Camellia sinensis. It has a long history of medicinal, the earliest documented was contained in "Shen Nong’s Materia Medica". Tea contains a variety of bioactive substances, epigallocatechin-3-gallate (EGCG) of the ester catechin has great development value, because it can exhibit a series of pharmacology functions, including anti-cancer, anti-mutagenic, anti tumor formation, anti-inflammatory, antiviral, free radical scavenging and antioxidant effects. The tea industry will develope rapidly in Enshi autonomous prefecture in recent years. In12th Five-Year Plan period, two hundred thousand mus new tea garden will be built, forty thousand mus old tea garden will be reformed every year, one hundred thousand mus high standards of clonal improved varieties tea garden will be built. That will produce a large number of tea heels in building and the reforming tea garden. The heels can be used to produce high purity EGCG. Therefore, this paper researched the extraction and purification process on the content of EGCG in Enshi tea heels.In this paper, the method to determine the content of EGCG product and which in tea heels by HPLC was established. The chromatographic conditions:the analytical column was C18(250mm×4.6mm,5um), the mobile phase consisted of acetonitrile-waterglacial acetic acid (14:84:2), the flow rate was1.0ml min-1and the detection wavelength was276nm. The linearity of EGCG was ranged from1.66to8.30ug, the relative recovery was100.26%(RSD=1.41%). The method is simple and accurate with good reprodu-cibility, which provide a basis to control the quality of raw material and EGCG product.In this paper, which used decoction method to study the conditions for the extraction process of EGCG in tea heels that with the amount of EGCG as index. Base on the single factor experiment, using L9(34) orthogonal design to determine the best extractive process conditions. Results indicated that the extraction technological parameters which selected were simple and stable.EGCG in tea extracts were separated and purified by macroporous adsorptive resin chromatography and gel chromatography. The technical conditions for purification of the EGCG in tea heels with macroporous resins was studied by using the absorption of static and dynamic state. Used the macroporous resins technological parameters, the purity of crude EGCG could obtain60%. The crude EGCG were further purified by glucan gel Sephadex LH-20. Base on the single factor experiment, using L9(34) orthogonal design to optimize the best purification process by glucan gel Sephadex LH-20was studied, with the recovery rate and the pure of EGCG as index. The optimum technological parameters are:the ratio of diameter to height was1:20, the elution solvent was10%of ethanol and contain2%glacial acetic acid solution, the elution rate was0.8ml·min-In this condition, the purity and recovery rate of EGCG purity can be up to95%.This study provides a suitable technology for obtaining EGCG from the tea heels. The solvent used is safe and non-toxic, which achieved the requirements of green chemistry really. The process has the advantages of simple operation, with the high extraction efficiency and economizing the solvent, which is suitable for industrial manufacture. |
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