Theaflavin-3-gallate, a black tea theaflavin monomer, formed in the oxidation of epicatechin (EC) and epigallocatechin gallate (EGCG) at the ratio of 1:1, is regarded as the biologically important active component of black tea and provides health benefits. Theaflavin-3-gallate also can be found in the leaves of black tea. Theaflavin-3-gallate act as prooxidants and induce oxidative stress with carcinoma cells more sensitive than normal fibroblasts. Theaflavin-3-gallate reacts directly with reduced glutathione (GSH) in a time- and concentration-dependent manner.
