The antiviral activity of plant extracts and of pure products was studied using a more complex technique which necessitates culture and maintenance of cellular tissues, growth of virus on those cells and testing of the antiviral activity by observing the absence or persistence of the cytopathogenic effect of virus according to whether the tested product has any antiviral effect or not.    From Wordnik.com.  [Chapter 12] Reference

If confirmed, these results could constitute a mechanism to control viral entry and cytopathogenic effects.    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference