Evaluation of Antiviral Activity of Zanthoxylum Species Against Picornaviruses

Human rhinoviruses and enteroviruses (family Picornaviridae) infect millions of people worldwide each year, but little is known about effective therapeutical treatment for the infection caused by these viruses. We sought to determine whether or not Zanthoxylum (Rutaceae) species can exhibit antiviral activity against picornaviruses. The leaf parts of four Zanthoxylum species were extracted with methanol, and the extracts were investigated for their antiviral activity against picornaviruses using cytopathic effects by cytopathic effect reduction. Leaf extracts of Zanthoxylum piperitum among four Zanthoxylum species were found to possess only broad-spectrum antipicornavirus activity against human rhninovirus 2 with a 50% inhibitory concentration (IC₅₀) value of 59.48 μg/mL, human rhinovirus 3 with an IC₅₀ value of 39.94 μg/mL, coxsackie A16 virus with an IC₅₀ value of 45.80 μg/mL, coxsackie B3 virus with an IC₅₀ value of 68.53 μg/mL, coxsackie B4 virus with an IC₅₀ value of 93.58 μg/mL, and enterovirus 71 virus with an IC₅₀ value of 4.48 μg/mL. However, ribavirin did not possess antiviral activity against human rhinovirus 3 and four enteroviruses. Therefore, leaves of Z. piperitum showed broad-spectrum antipicornavirus activity, and may be useful as a candidate for studying picornavirus agents and development of pharmaceuticals.