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. 2021 Jun 9;16(6):e0251649. doi: 10.1371/journal.pone.0251649

Fig 3. Both SARS-CoV-2 SP- and SARS-CoV SPΔCG614-PV’s infection was efficiently blocked by NhPV and Suramin.

Fig 3

A) Images of the dried Prunella Vulgaris flowers and its water extract (NhPV). B) The analysis of anti-SARS-CoV-2 activities of NhPV or Suramin. 293TACE2 cells were infected by equal amounts of SARS-CoV-2SPΔC-pseudotyped viruses in the presence of different dose of NhPV or Suramin. At 48 hrs pi, the Gluc activity in supernatants was measured. (% inhibition = 100 x [1 - (Gluc value in presence of drug)/(Gluc value in absence of drug)). C) The cytotoxicity analysis of NhPV and Suramin in 293TACE2 cells and VeroE6 cells. 293TACE2 cells or VeroE6 cells in 96 well plates were treated with different concentration of NhPV or Suramin for 3hrs, compounds were washed and replaced by fresh medium. At 48 hours, the cell Viability was tested by trypan blue assay. D) Infection inhibition of NhPV or Suramin on SARS-CoV-2-SPΔCG614-PVs in 293TACE2 cells. Equal amounts of SCoV-2-SPΔCG614-PVs (adjusted by p24 level) were used to infect 293TACE2 cells in presence of different concentrations of NhPV or Suramin, in indicated at bottom of the panel. At 48 hrs pi, Gluc activity in supernatants was measured and present as % inhibition. Means ±S.D. were calculated from duplicate experiments. E) 293TACE2 cells in 96-well plate were infected with SP△CG614-GFP+ PVs. After 48 hrs pi, GFP-positive cells (per well) were counted (left panel) and photographed by fluorescence microscope (top panel, a. Without drugs; b. Without infection; c. In the presence of NhPV (100 μg/ml); d. In the presence of Suramin (100 μg/ml). F) 293TACE2 cells in 96-well plate were infected with SARS-CoV SP-pseudotyped Luc+ MLV. At 48 hrs pi, the infected cells were lysed and cell-associated luc activity was measured and calculated as % inhibition (% inhibition = 100 x [1 - (Luc value in presence of drug)/(Luc value in absence of drug)). The results are the mean ±SD of duplicate samples, and the data are representative of results obtained in two independent experiments.