Figure 1.

Inhibition of phenothiazines on the infection of SARS-CoV-2, SARS-CoV, and MERS-CoV PsVs. (A) Schematic diagram of pseudotype antiviral assay. To produce pseudovirions, psPAX2 plasmids, and pHIV-Luciferase plasmids were co-transfected into HEK293T cells with pcDNA3.1-MERS-CoV S, pcDNA3.1-SARS-CoV S, pcDNA3.1-SARS-CoV-2 S, and pCMV-VSV-G expressing plasmids, respectively. To discover antiviral drugs, HEK293T-hACE2 cells were incubated with candidate compounds and different pseudoviruses. The cells were lysed and the luciferase activity was assessed 48 h post-infection. (B) Fourteen drugs were selected after the primary screening experiments using the library of US FDA-approved drugs against SARS-CoV-2 Omicron (BA.4) PsV. The inhibition percentages of selected compounds in the PsV assays are shown as 25 μM (blue dots) or 50 μM (red square dots). Hydroxychloroquine was treated as a positive control. (C) The chemical structure of perphenazine and the inhibitory activities of perphenazine against SARS-CoV-2, SARS-CoV, MERS-CoV, and VSV-G PsVs infection. (D) The chemical structure of acepromazine maleate and the inhibitory activities of acepromazine maleate against SARS-CoV-2, SARS-CoV, MERS-CoV, and VSV-G PsVs infection. (E) The chemical structure of fluphenazine decanoate and the inhibitory activities of fluphenazine decanoate against SARS-CoV-2, SARS-CoV, MERS-CoV, and VSV-G PsVs infection. (F) The chemical structure of prochlorperazine maleate and the inhibitory activities of prochlorperazine maleate against SARS-CoV-2, SARS-CoV, MERS-CoV, and VSV-G PsVs infection. (G) The chemical structure of alimemazine hemitartrate and the inhibitory activities of alimemazine hemitartrate against SARS-CoV-2, SARS-CoV, MERS-CoV, and VSV-G PsVs infection. In parallel, the toxicities of these compounds in HEK293T-hACE2 cells were analyzed by the CCK-8 assays (blue squares). Samples were tested in triplicate, and the experiments were repeated at least twice.