Antiviral activity in Argentine medicinal plants.

In an ethnopharmacological screening of selected medicinal plants used in Argentina for the treatment of infectious diseases, aqueous extracts of five species were assayed in vitro to detect antiviral activity against herpes simplex virus type 1 (HSV-1), respiratory syncytial virus (RSV) and adenovirus serotype 7 (ADV-7). Polygonum punctatum, Lithraea molleoides, Sebastiania brasiliensis and Sebastiania klotzschiana but not Myrcianthes cisplatensis showed in vitro antiherpetic activity with 50% effective dose (ED50) ranging from 39 to 169 microg/ml. P. punctatum, L. molleoides and M. cisplatensis showed antiviral activity against RSV with ED50 ranging from 78 to 120 microg/ml. None of the extracts had antiviral activity against ADV-7. The differences between their maximal non cytotoxic concentration and their antiviral activity values were high enough to justify further analysis.