Dehydrojuncusol, a Natural Phenanthrene Compound Extracted fromJuncus maritimusIs a New Inhibitor of Hepatitis C Virus Replication

AbstractRecent emergence of direct acting antivirals (DAAs) targeting hepatitis C virus (HCV) proteins has considerably enhanced the success of antiviral therapy. However, the appearance of DAA resistant-associated variants is a cause of treatment failure, and the high cost of DAAs renders the therapy not accessible in countries with inadequate medical infrastructures. Therefore, search for new inhibitors and with lower cost of production should be pursued. In this context, crude extract ofJuncus maritimusLam. was shown to exhibit high antiviral activity against HCV in cell culture. Bio-guided fractionation allowed isolating and identifying the active compound, dehydrojuncusol. A time-of-addition assay showed that dehydrojuncusol significantly inhibited HCV infection when added after virus inoculation of HCV genotype 2a (EC50= 1.35 µM). This antiviral activity was confirmed with a HCV subgenomic replicon and no effect on HCV pseudoparticle entry was observed. Antiviral activity of dehydrojuncusol was also demonstrated in primary human hepatocytes. Noin vitrotoxicity was observed at active concentrations. Dehydrojuncusol is also efficient on HCV genotype 3a and can be used in combination with sofosbuvir. Interestingly, dehydrojuncusol was able to inhibit replication of two frequent daclatasvir resistant mutants (L31M or Y93H in NS5A). Finally, resistant mutants to dehydrojuncusol were obtained and showed that HCV NS5A protein is the target of the molecule. In conclusion, dehydrojuncusol, a natural compound extracted fromJ. maritimus, inhibits infection of different HCV genotypes by targeting NS5A protein and is active against HCV resistant variants frequently found in patients with treatment failure.ImportanceTens of millions of people are infected with hepatitis C virus (HCV) worldwide. Recently marketed direct acting antivirals (DAAs) targeting HCV proteins have enhanced the efficacy of the treatment. However, due to its high cost, this new therapy is not accessible to the vast majority of infected patients. Furthermore, treatment failures have also been reported due to appearance of viral resistance. Here we report on the identification of a new HCV inhibitor, dehydrojuncusol that targets HCV NS5A and is able to inhibit replication of replicons harboring resistance mutations to anti-NS5A DAAs used in current therapy. Dehydrojuncusol is a natural compound isolated fromJuncus maritimus, a halophilic plant species very common in the coastlines worldwide. This molecule might serve as a lead for the development of new therapy more accessible to hepatitis C patients in the future.