Effect of theaflavin derivatives on influenza A virus / 中草药

ABSTRACT

Objective: To study the anti-influenza A virus effect of theaflavin derivatives which contain theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B), and theaflavin-3, 3'-digallate (TF3) and to investigate the mechanism. Methods: The inhibition of theaflavin derivatives on A/Thailand/Kan353/2004 H5N1 pseudovirus was investigated using pseudotype H5N1 virus system. Hemagglutination inhibition assay and neuraminidase (NA) inhibition assay were used to investigate the mechanism for their anti-influenza activities. The inhibition of theaflavin derivatives on influenza A virus FM_1 was observed by H1N1 FM_1 system. Cytotoxicity of theaflavin derivatives on MDCK cells was determined by MTT assay. Results: Theaflavin derivatives could significantly inhibit the infection of pseudovirus H5N1 with IC50 of (151.88 ± 18.95) μg/mL. It had no inhibition on HA1 subunit. Theaflavin derivatives had the inhibition on NA with IC50 of (129.09 ± 1.33) μg/mL. Theaflavin derivatives showed a significant inhibitory activity on FM_1 influenza virus strain in MDCK cells. Theaflavin derivatives showed the low cytotoxicity on MDCK cells with CC50 of (879.89 ± 4.54) μg/mL. Conclusion: Theaflavin derivatives could inhibit the infection of avian influenza virus through the combination with hemagglutinin (HA) HA2 subunit and inhibit the activity of viral NA to some extent, which indicates that the anti-H5N1 avian influenza virus of theaflavin derivatives may be through multi-targets.