Theaflavin 3,3'-digallate

Theaflavin 3,3'-digallate (TF-3) is a potent Zika virus (ZIKV) protease inhibitor with an IC₅₀ of 2.3 μM. Theaflavin 3,3'-digallat directly binds to ZIKVpro (K_d=8.86 µM) and inhibits ZIKV replication. Theaflavin 3,3'-digallat inhibits the activity of gp41 and NS2B-3 protease and has antiviral activity against HSV and HIV-1^[1]. Theaflavin 3,3'-digallate, the typical pigment in black tea, is a potent antitumor agent^[2]. In Vitro: Theaflavin 3,3'-digallate (TF-3; 6.25, 12.5, 25 μM; 24 hours) markedly reduces viral RNA copy numbers and NS3, U87 MG protein expression in a dose-dependent manner^[1].
Theaflavin 3,3'-digallate inhibits dose-dependently ZIKV replication in Vero E6 cells (EC₅₀=7.65 μM). Theaflavin 3,3'-digallate has minor cytotoxicity up to 40 μM in Vero E6 cells. Theaflavin 3,3'-digallate can inhibit the post-entry events of the ZIKV replication cycle from gene transcription and translation levels^[1].
Theaflavin 3,3'-digallate is generally regarded as the effective component for the inhibitory effects against carcinogenesis without adverse side effects by affecting multiple signal transduction pathways, such as upregulating p53 and p21, inhibiting phosphorylation of the cell survival protein Akt and MAPK pathway, downregulation of NF-κB, shifting the ratio between pro-/antiapoptotic proteins. Theaflavin 3,3'-digallate causes a rapid and sustained decrease in phospho-ERK1/2 and -MEK1/2 protein expression. Theaflavin 3,3'-digallate inhibits HCT116 cell growth with an IC₅₀ of 17.26 μM^[2].