Inhibition of dengue viral infection by diasarone-I is associated with 2'O methyltransferase of NS5

Dengue virus (DENV) is the most prevalent mosquito borne viral pathogen worldwide. However, antiviral drugs against this infection are not available. To identify novel anti-DENV compound from traditional Chinese medicine, we discovered the ethanol extract of Acorus tatarinowii Schott containing potent anti-DENV activity and diasarone-I was isolated from this extract. Diasarone-I has antiviral effect with half maximal effective concentration (EC50) of 4.5 mu M and half maximal cytotoxicity concentration (CC50) of > 80 mu M. Time of drug addition assay suggested that this compound inhibited at RNA replication step in the DENV life cycle. Further, in silico analysis indicated that diasarone-I might act as an inhibitor of 2'O Methyltransferase of NS5. Diasarone-I has also decreased the DENV2-induced STAT1 phosphorylation and ISGs. In summary, we suggest that diasarone-I may be a 2'O Methyltransferase inhibitor and might serve as a potential candidate for the treatment of DENV2 infections.