Fig. 5From: Quercetin inhibits SARS-CoV-2 infection and prevents syncytium formation by cells co-expressing the viral spike protein and human ACE2Quercetin inhibition of furin activity. As described under Materials and Methods, furin proteolysis of the fluorogenic Pyr-RTKR-AMC substrate was assayed in absence or the presence of increasing concentrations of: (A) quercetin or (B) the synthetic Dec-RVKR-CMK inhibitorBack to article page