Artemisia capillaris inhibited enterovirus 71-induced cell injury by preventing viral internalization

Artemisia capillaris (A. capillaris) is a common herbal drug used for thousands years in ancient China. A. capillaris has been empirically used to manage hand-foot-mouth disease (HFMD), which is commonly caused by enterovirus 71 (EV71). EV71 can cause meningoencephalitis with mortality and neurologic sequelae without effective management. It is presently unknown whether A. capillaris is effective against EV71 infection. To test the hypothesis that it could protect cells from EV71-induced injury, a hot water extract of A. capillaris was tested in human foreskin fibroblast cells (CCFS-1/KMC) and human rhabdomyosarcoma cells (RD cells) by plaque reduction assay and flow cytometry. Inhibition of viral replication was examined by reverse quantitative RT-PCR (qRT-PCR). Its effect on translations of viral proteins (VP0, VP1, VP2, protease 2B and 3AB), and apoptotic proteins were examined by western blot. A. capillaris was dose-dependently effective against EV71 infection in both CCFS-1/KMC cells and RD cells by inhibiting viral internalization. However, A. capillaris was minimally effective on viral attachment, VP2 translation, and inhibition of virus-induced apoptosis. Further isolation of effective molecules is needed. In conclusion, A. capillaris has anti-EV71 activity mainly by inhibiting viral internalization. A. capillaris would be better to manage EV71 infection in combination with other agents.