Biotransformation of catechin and extraction of active polysaccharide from green tea leaves via simultaneous treatment with tannase and pectinase.

Green tea is a dietary source of bioactive compounds for human health. Enzymatic treatments induce the bioconversion of bioactive components, which can improve biological activities. In this study, we investigated the effect of simultaneous treatment with tannase and Rapidase on biotransformation of catechins and extraction of polysaccharide from green tea extract (GTE). Tannase and pectinase treatments induced the biotransformation of catechins and altered tea polysaccharide () content. The addition of GTE to the enzyme reaction resulted in a significant increase in degallated catechins, including gallic acid, a product of the tannase reaction (314.5-4076.0 µg mL(-1)) and a reduction in epigallocatechin gallate (EGCG). Biotransformation of catechins improved the radical scavenging activity of GTE. Pectinase treatment led to change of TPS composition in GTE by hydrolyzing polysaccharides. In addition, pectinase-driven hydrolysis in polysaccharides significantly increased TPS-induced Interleukin 6 (IL-6) production in macrophages. In particular, treatment of Rapidase (TPS-Ra) led to the highest IL-6 production among TPS samples, similar to treatment of highly purified pectinase (TPS-GTE), a positive control. Simultaneous processing with tannase and Rapidase can be an efficient method for the extraction of bioactive polysaccharides and biotransformation of catechins with enhanced radical scavenging activity from green tea.