Licochalcone A inhibits enterovirus A71 replication in vitro and in vivo.

Enterovirus A71 (EV-A71) is one of the main causative agents of hand-foot-mouth disease (HFMD) and causes serious neurological complications. However, no effective therapy is currently available for treating these infections. Therefore, effective drugs to prevent and treat EV-A71 infections are urgently needed. Here, we demonstrated that treatment with Licochalcone A (LCA) significantly inhibited EV-A71 replication in a dose-dependent manner, with an EC50 of 9.30 μM in RD cells and 5.73 μM in Vero cells. The preliminary results on the inhibition mechanism showed that LCA exerted antiviral effects by interfering with the early step of viral replication. We further demonstrated that LCA showed potent antiviral activity against many enteroviruses, including EV-A71 (strain C4), EV-A71 (strain H), and coxsackievirus A16 (CV-A16). Furthermore, LCA could effectively prevent the clinical symptoms and death of virus infected mice and decreased viral load in EV-A71-infected mice. Taken together, our studies showed for the first time, that LCA is a promising EV-A71 inhibitor and provide important information for the clinical development of LCA as a potential new anti-EV-A71 agent.