| abstract |
The way the SARS-CoV-2 virus infects the cell is a complex process and comprises four main stages: attachment to the cognate receptor, cellular entry, replication and cellular egress. Targeting binding of the virus to the host receptor in order to prevent its entry has been of particular interest. We tested 56 polyphenols, including plant extracts, brazilin, theaflavin-3,3'- digallate, and curcumin displayed the highest binding with the receptor-binding domain of spike protein, inhibiting viral attachment to the human angiotensin-converting enzyme 2 receptor, and thus cellular entry of pseudo-typed SARS-CoV-2 virions. Both,theaflavin-3,3'-digallate at 25 μg/ml and curcumin above 10 μg/ml concentration, showed binding with the angiotensin- converting enzyme 2 receptor reducing at the same time its activity in both cell-free and cell- based assays. Our study also demonstrates that brazilin and theaflavin-3, 3'-digallate, curcumin, decrease the activity of transmembrane serine protease 2 both in cell-free and cell-based assays and moderately increased endosomal/lysosomal pH. |