The olive leaf extract exhibits antiviral activity against viral ha emorrhagic septicaemia rhabdovirus (VHSV)

A commercial plant extract derived from olive tree leaf (Olea europaea) (LExt) and its major compound, oleuropein (Ole), inhibited the in vitro infectivity of the viral haemorrhagic septicaemia virus (VHSV), a salmonid rhabdovirus. Incubation of virus with LExt or Ole before infection reduced the viral infectivity to 10 and 30%, respectively. Furthermore, LExt drastically decreased VHSV titers and viral protein accumulation (virucidal effect) in a dose dependent manner when added to cell monolayers 36 h post-infection. On the other hand, both the LExt and Ole were able to inhibit cell-to-cell membrane fusion induced by VHSV in uninfected cells, suggesting interactions with viral envelope. Therefore, we propose that O. europaea could be used as a potential Source of promising natural antivirals, which have demonstrated to lack impact on health and environment. In addition, Ole could be used to design other related antiviral agents. (c) 2005 Elsevier B.V. All rights reserved.