Evaluation of the antiviral activity of an aqueous extract from Phyllanthus orbicularis

The antiviral and cytotoxic activity of Phyllanthus orbicularis, a member of the Euphorbiaceae, was evaluated in tissue culture. An aqueous extract made from leaves and stems of this plant exhibited selective antiviral indexes of 12.3 and 26 against bovine herpesvirus type 1 and herpes simplex virus type 2, respectively, showing no selective antiviral activity against adenovirus type 5 and mengovirus. Incubation with this plant extract during cell culture infection, impaired the productive replication of both herpes viruses in an extract concentration-dependent manner, also depending on the multiplicity of infection (MOI) used. The results obtained suggested that the P. orbicularis antiviral activity might be partially due to a direct interaction with virus particles or their entry into the cell, instead of interfering with intracellular virus-specific macromolecular synthesis.