Inhibitory activity of Euterpe oleracea Mart. fruit extract in West Nile virus infection.

West Nile virus (WNV) is a neurovirulent arbovirus whose epidemic capacity is enhanced by the wide occurrence of competent vectors and susceptible avian amplifying hosts. In this study, we investigated the antiviral potential of Euterpe oleracea Mart. fruit extract (EoFE) in WNV infection of monkey kidney (Vero) cell cultures. A chromatographic authentication of the extract revealed a typical two-peak fingerprint attributable to the major anthocyanins of the fruit. As assessed by plaque assays in Vero cells, the extract showed a significant concentration-dependent antiviral effect when present throughout the infection procedure, reaching a maximum inhibition of 66.8 % at 2 mg/mL without significant cytotoxicity or direct action on virus particles. A time-of-addition assay revealed that this anti-WNV effect was mostly exerted after virus entry, as incubation of Vero cells with EoFE before or during virus addition resulted in a nonsignificant decrease of infection efficiency. These results demonstrated a promising potential of EoFE in inhibiting WNV infection that can be further explored as an antiviral strategy.