Theaflavins (TFs) is the family name of a multitude of chemical elements. Theaflavins in varying chemical combinations shows effectiveness as an anti-oxidant and scavenger of free radicals. In dry standardized extract form, TFs can promote anti-oxidization in the enzyme system such as superoxide dismutase (SOD), glutathione peroxidase, thereby effectively inhibiting peroxidation of lipids. The total antioxidant activity (TAA) of tea is much higher than that of many popular herbal extracts, such as dry standardized extracts of Ginkgo biloba, bilberry, grape seed extract (OPC) and so on.

Flavonoid ingredients of black tea or TFs are observed to inhibit vitro lipid peroxidation in the erythrocyte membrane ghost and microsomal structures. TFs also shows inhibition of DNA single-strand cleavage and mutagenicity, both induced by hydrogen peroxide. These results suggest that TFs scavenges radicals to produce antioxidative and antimutagenic effects. It is also found that the gallic acid moiety of TFs is responsible for their potent antioxidative activities.

Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation reveals that the antioxidant activity of TFs is the strongest among all of tea extracts, even the well-known anti-oxidant EGCG.

Using the process of reconstituting black tea until it is free of all catechins, incrementally adding catechins shows that among all of the consitiuents contributing to the overall effect of BT, theaflavins are the most powerful in abrogating NO production.

From the above table, we can see that the antioxidative activity of TF is about 10 times stronger than Catechin (Biol. Pharm. Bull. 17(1) 146-149 (1994)).