Antiviral activity of raoulic acid from Raoulia australis against Picornaviruses

Abstract

RNA viruses are a major source of respiratory diseases worldwide. The lack of effective therapeutical treatment underlines the importance of research for new antiviral compounds. Raoulic acid is a principal ingredient of the plant Raoulia australis Hook. F. Antiviral assay using cytopathic effect (CPE) reduction method showed that raoulic acid possessed strong antiviral activity against human rhinovirus 2 (HRV2) with a 50% inhibition concentration (IC50) value of less than 0.1 μg/ml, human rhinovirus 3 (HRV3) with a IC50 value of 0.19 μg/ml, coxsackie B3 (CB3) virus with IC50 values of 0.33 μg/ml, coxsackie B4 (CB4) virus with IC50 values of 0.40 μg/ml, and enterovirus 71 (EV71) virus with IC50 values of less than 0.1 μg/ml. However, the compound did not possess antiviral activity against influenza A (Flu A/PR, Flu A/WS, H1N1) and B viruses at four concentrations ranging from 0.1 to 100 μg/ml.