Selection of polyphenol oxidase affects biotransformation efficacy of targeted theaflavins

Theaflavins in black tea and other fermented tea have attracted many studies because of their stronger antioxidant and anti-inflammatory effects among bioactives other than catechins. However, within the four major theaflavins, namely theaflavin, theaflavin-3-O-gallate, theaflavin-3′-O-gallate and theaflavin-3,3′-O,O-digallate, their biological properties are different. A method to efficiently and selectively synthesize targeted theaflavins with desired property is a key condition for further evaluation. Herein, we have summarized the sources of polyphenol oxidase (PPO) and the yields of total and individual theaflavins based on some available publications. This overview lays the foundation for a comprehensive review in this area of researchin the near future.