In vitro antiviral activity of Tunisian propolis

The in vitro effect of propolis on several RNA and DNA viruses including Coxsackie virus type B3 (CVB-3) and Herpes virus type 2 (HSV-2), was investigated. The overuse of some drug as a usual therapy led to the emergence of resistant strains. Therefore, the search for new alternative molecules to overcome this obstacle is needed. In this objective, Propolis is used for its CVB-3 and HSV-2 activity. Propolis samples from four different origins in Tunisia were evaluated for their cytotoxicity on Vero cells by the MTT test and anti CVB-3 and HSV-2 activity by plaque reduction assay. Only the extract of propolis collected from the region of Zelligua exhibited activity against CVB-3 with a 50% inhibitory concentration (IC50) and a selectivity index (SI) of 30 and 9μg/mL, respectively. In addition, the study of the antiviral mode of action revealed that this extract exerts a virucidal action both during the entry of viruses and the release of the newly formed virions. The active extract went through a liquid-liquid fractionation and only the Ethyl Acetate fraction was found active against CVB-3.