Inhibitory effect of aqueous extract of Echinacea purpurea and Nerium oleander on HSV-1 multiplication

Treatment of HSV-1 infections with the available chemical drugs may have some problems such as drug resistance and virus latency. Therefore، there is a requirement for new antiherpes drugs in today''s world. The present study was carried out to analyze the inhibitory effect of Echinacea purpurea and Nerium oleander plants with ethnomedical background on HSV-1 replication. Plants were extracted by decoction method to obtain aqueous extract. These extracts were screened for their cytotoxicity against Hep-2 cell line by CPE (cytopathic effect) assay. Antiviral effect of the plant extracts were determined by the virus cytopathic effect inhibition assay. Nerium oleander extract had the highest toxicity (>0. 1 μg/ml) on Hep-2 cells and Echinacea purpurea extract exhibited significant antiherpes effect at nontoxic concentrations used on the cell lines. Findings indicated that Echinacea purpurea extract inhibited HSV-1 multiplication at concentrations >400 μg/ml. Echinacea purpurea plant had no any effect on cells at nontoxic concentrations and inhibited HSV-1 multiplication at concentrations >400 μg/ml. Further research is needed to find out the anti herpetic mechanism of this plant.