| 초록 |
A fermented black tea includes various polyphenolic catechins that constitute more than 70% of the dry mass of a black tea aqueous infusion. The polymeric catechins have been reported to have greater anti-oxidant effects than monomeric catechins. The catechins as substrates are oxidized with polyphenol oxidases(PPO) in fermentation process. In this study, epigallocatechin-3-O-gallate(EGCG), is polymerized to dimers through radical oxidative reaction using laccase, a part of the tea PPOs. We have focused on theacitrins(TCs), dehydrotheasinensin, and theasinensin(TSs), which are dimers of EGCG. They are analyzed by LC/MS/MS to identify their structures. The dimers are dismutated with heating process after oxidation step in order to mimic the design of drying in the last step of fermentation. The product of this in vitro biomimetic process, theasinensin A, has great hypoglycemic effect and stability. Thus, it was obtained as the target product and purified through column chromatography. |
