Fig. 6

Decaffeinated coffee still has the ability to block SARS-CoV-2 variants infection. a HPLC analysis was used to examine the caffeine and CGA content of commercially available decaffeinated coffee. b By Vpp (MOI = 0.1), regular and decaffeinated coffee were verified to reduce the entry of wild-type SARS-CoV-2 on 293 T-ACE2 cells. c Through Vpp (MOI = 0.1), regular and decaffeinated coffee were examined to inhibit the entry of wild-type, Alpha, Delta, and Omicron variants on 293 T- ACE2 cells. d Regular and decaffeinated coffee were analyzed for the effect of blocking ACE2/spike interaction by Enzyme-linked immunosorbent assay. e Regular and decaffeinated coffee were examined to decrease TMPRSS2 activity by cell-based TMPRSS2 enzyme activity assay. Error bars indicated the standard error of the mean in triplicate independent experiments. P values were obtained by the Student T-test. Statistical significance was concerned as *P < 0.05, **P < 0.01 or ***P < 0.001