Fig. 3.

Antiviral activity of active components isolated from APRG64 against SARS-CoV-2. Vero cells were seeded 1 day before infection. (A) Cells were infected with SARS-CoV-2 at 0.01 multiplicity of infection (MOI) and treated with compounds 1–12 of APRG64 at 1, 5, or 25 µg/mL for 1 h, followed by washing three times with PBS. Three days later, cells were fixed and stained to visualize plaques. Plaque reduction rates are shown. (B) Cells were infected with SARS-CoV-2 at 0.3 MOI and treated with APRG64, compounds 1, 7, or 12, at 5 or 25 µg/mL for 1 h. After washing three times with PBS, cells were incubated for an additional 72 h. Cell supernatants were analyzed for the SARS-CoV-2 spike proteins using enzyme-linked immunosorbent assay (ELISA). (C) Cells were infected with SARS-CoV-2 at 0.3 MOI for 1 h, followed by washing three times with PBS. Cells were treated with compounds 1, 7, or 12. After 72 h, cell supernatants were analyzed for SARS-CoV-2 spike protein using ELISA. Data are representative of three independent experiments. *p < 0.05; ^**p < 0.01; ^***p < 0.001, compared with mock-treated cells (Con).