Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses.

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF(1)), theaflavin-3-gallate (TF(2)A), theaflavin-3'-gallate (TF(2)B), and theaflavin-3,3'-digallate (TF(3))) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (-)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF(3) was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF(1) suppressed superoxide. Positive antioxidant capacities of TF(2)B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.