Antiviral activity of Ageratina havanensis and major chemical compounds from the most active fraction

The antiviral activity of extracts obtained from Ageratina havanensis (Kunth) R.M.King & H.Rob., Asteraceae, against rabbit vesivirus (RaV) (Caliciviridae) and human herpes simplex viruses type 1 and 2 (HSV-1, HSV-2) (Herpesviridae) were analyzed, and the main metabolites from the most active extract were isolated and characterized. The antiviral properties were investigated by measuring the inhibition of viral-induced cytopathic effect in Vero cells. The strongest inhibitory effects were found for ethyl acetate extract from leaves (SI=5 for RaV and SI=5.4 for HSV-1). The crude ethyl acetate extract was further fractionated by chromatographic methods and the structures of isolated compounds were established through comprehensive spectroscopic analyses, including IR, 2D NMR and MS. Four flavonoids were identified: 5,4'-dihydroxy-7-methoxyflavanone (sakuranetin), 3,5,4'-trihydroxy-7-methoxyflavanone (7-methoxyaromadendrin), 4'-O-beta-D-glucosyl-5,3'-dihydroxy-7-methoxyflavanone (4'-O-beta-D-glucosyl-7-methoxy-eriodictyol) and 4'-O-beta-D-glucosyl-5-hydroxy-7-methoxyflavanone (4'-O-beta-D-glucosylsakuranetin). This is the first report on antiviral activity for Ageratina havanensis.