Highly efficient synthesis of theaflavins by tyrosinase from mushroom and its application to theaflavin related compounds

Abstract

Enzymatic synthesis of black tea theaflavins was investigated with tyrosinase, laccase, bilirubin oxidase, and crude polyphenol oxidase from Camellia sinensis which show polyphenol oxidase activities. Among them tyrosinase was found to form theaflavins most effectively. The differences among the enzymes in the formation rate of theaflavins could be explained by the initial oxidation velocity ratio of (-)-epicatechin (EC) to (-)-epigallocatechin (EGC) by the enzymes. That is, the formation rate of theaflavins increased with an increasing ratio of EC/EGC. Maximum production (more than 80% yield) of theaflavins (theaflavin, theaflavin 3-O-gallate, theaflavin 3′-O-gallate, and theaflavin 3, 3′-di-O-gallate) was achieved based on the catechol-type catechin usage when the tyrosinase reaction was performed with the pyrogallol-type/catechol-type catechin molar ratio of more than 3.0 at 40 °C and pH 4.5–5.0. In addition, the above method was applied to the synthesis of epitheaflagallin 3-O-gallate from (-)-epigallocatechin gallate and pyrogallol, and epitheaflavic acid 3-O-gallate from (-)-epicatechin gallate and gallic acid.