Activity of methanolic Andrographis paniculate crude extract and its purified andrographolide against Japanese encephalitis virus

Abstract

Infection of Japanese encephalitis virus (JEV) generates brain swelling, namely Japanese encephalitis (JE) in human. This virus is spread by Culex spp. mosquitoes and causes 30% case-fatality rate in Asia and Western Pacific regions annually. No specific cure for the disease is available. Andrographis paniculate methanolic extract and its purified andrographolide exhibit anti-inflammatory and antiviral properties. Our study is focused to antiviral activity of A. paniculate extracts and its elements against JEV in vitro. Half-maximal cytotoxicity (CC50) and the maximum non-toxic doses (MNTD) of A. paniculata in SK-NMC and LLC-MK2 are less than the CC50 and MNTD of andrographolide in SK-NMC and LLC-MK2 at 3 days-post treatment by MTT colorimetric assay. Both A. paniculata and andrographolide have antiviral effect by simultaneous treatment more than pre-treatment and post-treatment at 3 days-post treatment by time-of-addition assay. Antiviral action of these agents interfered virus attachment and had virucidal activity. The results indicated that A. paniculata and andrographolide have the potential antiviral activity against JEV.