Screening of Natural Extracts for Inhibitors against Japanese Encephalitis Virus Infection

Guo, Jiao; Jia, Xiaoying; Liu, Yang; Wang, Shaobo; Cao, Junyuan; Zhang, Bo; Xiao, Gengfu; Wang, Wei

JEV inhibition with ouabain and digoxin occurs via Na ؉ /K ؉ -ATPase. Na ϩ /K ϩ -ATPase is the only target of cardiac glycosides that has been found to date. To confirm whether JEV inhibition occurs via blockade of Na ϩ /K ϩ -ATPase, the infected cells were treated with DMSO and two compounds in the presence of increasing NaCl and KCl, and two compounds inhibited JEV in a dose-responsive manner. Furthermore, at the same concentration of digoxin, JEV inhibition reduced with the decrease of NaCl (Fig. 5A ) but with an increase of KCl (Fig. 5B ). Under the same experimental conditions, the results of ouabain action were consistent with digoxin ( Fig. 5C and D) , which indicated that the JEV-inhibiting effect of both compounds is positively correlated with extracellular NaCl but inversely correlated with KCl. These results confirm that both ouabain and digoxin exert the antiviral effect by targeting the Na ϩ /K ϩ -ATPase.