Clofazimine derivatives as potent broad-spectrum antiviral agents with dual-target mechanism.
Zhang X, Shi Y, Guo Z, Zhao X, Wu J, Cao S, Liu Y, Li Y, Huang W, Wang Y, Liu Q, Li Y, Song D.
Thirty-two clofazimine derivatives, of which twenty-two were new, were synthesized and evaluated for their antiviral effects against both rabies virus and pseudo-typed SARS-CoV-2, taking clofazimine (1) as the lead. Among them, compound 15f bearing 4-methoxy-2-pyridyl at the N5-position showed superior or comparable antiviral activities to lead 1, with the EC<sub>50</sub> values of 1.45 μM and 14.6 μM and the SI values of 223 and 6.1, respectively. Compound 15f inhibited rabies and SARS-CoV-2 by targeting G or S protein to block membrane fusion, as well as binding to L protein or nsp13 to inhibit intracellular biosynthesis respectively, and thus synergistically exerted a broad-spectrum antiviral effect. The results provided useful scientific data for the development of clofazimine derivatives into a new class of broad-spectrum antiviral candidates.