Quinazoline derivatives inhibition the effectiveness of the Japanese encephalitis virus

[[abstract]]Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus with a positive-sense single-stranded RNA genome, causing encephalitis with permanent neurological sequelae in Asia. Currently, there is no effective cure except vaccination. Quinazolinone derivatives(QD) have anti-malarial, anti-inflammatory, anti-bacterial and anti-tumor activities. The aim of this study is to discover antiviral activity of novel QDs against JEV in vitro using the assays ofcytopathic effectinhibition, apoptosis with propidiumiodide(PI) stain, plaque reduction, reporter assay, virus attachment, virucidal activity, and Western blotting. Of 13 QDs, QD52, QD56, QD57, and QD58 significantly inhibited cytopathic effect (CPE) of JEV infected cells with a MOI of 0.5. The 50% cytotoxic concentration (CC50) values of QD52, QD56, QD57, and QD58were71.37μM, 41.31μM, more than 100μM and 70μM, respectively. QD52, QD56, QD57, and QD58 dose-dependently inhibited viral CPE, apoptosis and virus yields. The 50% inhibitory concentration (IC50) values of QD52, QD56, QD57, and QD58 for plaque reduction were28.65 μM, 17.54 μM, 46.4 μM, and 45.76μM, respectively. These four QDs did not block virus attachment. QD52 had a virucidal activity in dose-dependent manners. QD56 activated IRF-3 signaling pathway via the increase of IRF-3 phosphorylation