Purification Of EGCG From Green Tea And Its Interaction With Bovine Serum Albumin

These investigations at home and abroad confirmed that the tea polyphenols (TP) played an important role in anticancerr, anti-aging, antiradiance. The most important components of tea polyphenols is EGCG which owned the maximum content and strongest bioactivity compared to other tea polyphenols. We optimized the EGCG-purified system, and studied the bonding mechanism of EGCG to BSA with spectral methods.1,Through a combination of caffeine precipitation, solvent extraction and flash silica gel column chromatography, a method of separation and purification of EGCG from green tea was suggested. The operating conditions were investigated and optimized, the optimum concentration of caffeine was 30 mmol L-1. The extractant was ethyl acetate. The eluting solvent of silica gel column chromatography was ethyl acetate-petroleum ether-trifluoroacetic acid 3:2:0.025. The chromatographic purities of EGCG and ECG were 97.67% and 95.43%,respectively.2,The binding of EGCG to BSA were investigated for the first time with spectral methods, including fluorescence and absorption spectrometry under simulative physiological conditions. The binding constant K of EGCG and BSA was 2.18×105 L mol-1 which was determined by fluorescence quenching method. The number of binding sites n was 1. The binding distance R between BSA and EGCG was 2.795nm which was also obtained according to F?rster theory of non-radiation energy transfer. The effects of Al3+, Cu2+, Mg2+ and Fe2+ on the binding interaction between EGCG and BSA were studied. The effect of EGCG on the conformation of BSA was also analyzed by synchronous fluorescence spectroscopy.