Fig. 2

RDS inhibits SARS-CoV-2(GFP) pseudovirus infection of A549(ACE2) cells. A A549(ACE2) cells were treated with serially diluted RDS for 30 min, and then infected with SARS-CoV-2(GFP) pseudovirus. Cells were washed to remove the virus and RDS, and cultured in the absence of RDS. Inhibition of viral infection was quantified by flow cytometry. Uninfected cell and SARS-CoV-2(GFP)-infected but RDS-untreated cells were used as controls. The percentages of GFP + cells are shown. PI, propidium iodide. B Quantification of the cytotoxicity of RDS. A549(ACE2) cells were treated with serially diluted RDS for 4 h, washed to remove RDS, and cultured in the absence of RDS for 48 h. Cells were stained with propidium iodide to identify dying and dead cells, and analyzed with flow cytometry. The dose–response cytotoxicity curve was plotted, and the LC₅₀ of RDS was calculated to be at 1:11.9 dilution