Antiviral effect and mode of action of methanolic extract of Verbascum thapsus L. on pseudorabies virus (RC/79 strain)

ESCOBAR F.M.; SABINI C.; ZANON S.; TONN C.; SABINI L.

NATURAL PRODUCT RESEARCH

TAYLOR & FRANCIS LTD

Año: 2011

1478-6419

Methanolic extract of Verbascum thapsus was evaluated for antiviral activity against pseudorabies virus, RC/79 strain (PrV) and cytotoxic activity on Vero cells. The extract showed CC50 values of 1100 µg mL-1 and 1426 µg mL-1 by NRU and MTT assays, respectively. The 50% inhibitory concentration of the extract for PrV plaque formation was determined at 35 µg mL-1, and selectivity index were 31.4 (NRU) and 40.7 (MTT). When cells were pre-treated with the extract prior to virus infection, the inhibition in plaque formation was 70%. Pseudorabies virus was highly inhibited when it was incubated with plant extract or when the extract was added during the adsorption phase (99%). However, no inhibitory effect could be observed when the extract was added to the cells after adsorption period. Thus, results suggest that the methanolic extract of Verbascum thapsus may contain bioactive compound(s) that affected PrV mostly adsorption phase.