Theaflavin (TF) and its derivatives, known collectively as theaflavins, are antioxidant polyphenols that are formed from the condensation of flavan-3-ols in tea leaves during the enzymatic oxidation (fermentation) of black tea. Theaflavin-3-gallate, theaflavin-3'-gallate, theaflavin-3-3'-digallate are the main theaflavins. Theaflavins are types of thearubigins, and are therefore reddish in color. Epigallocatechin gallate (EGCG) will metabolize into some theaflavins in the liver.