Fig. 3: GRL-1720 and 5h exert potent activity against SARS-CoV-2^WK-521.

VeroE6 cells were exposed to SARS-CoV-2^WK-521 for 1 h, the virus was washed off, and the cells were cultured in the presence of various concentrations of test compound for 3 days. The images shown are those captured under light microscopy. VeroE6 cells cultured alone (top left) appear to be robust; however, those exposed to SARS-CoV-2^WK-521 and cultured in the absence of test compounds, a number of cells were destroyed by the cytopathicity of the virus and appear granular (top right). VeroE6 cells exposed to the virus and cultured with each of the two compounds, GRL-1720 and 5h (at 1, 10 and 100 µM). The virus-exposed cells cultured with 100 µM, all the cells appeared to be completely protected. Representative images from three independent experiments are shown. Scale bar = 200 µm.