Design, Synthesis, and Evaluation of Novel Enterovirus 71 Inhibitors as Therapeutic Drug Leads for the Treatment of Human Hand, Foot, and Mouth Disease

Human hand, foot, and mouth disease (HFMD) is a serious public health threat with high infection rates in children and infants who reside in Asia and the Pacific regions, and no effective drugs are currently available. Enterovirus 71 (EV71) and coxsackievirus A16 are the major etiological pathogens. Based on an essential hydrophobic pocket on the viral capsid protein VP1, we designed and synthesized a series of small molecular weight compounds as inhibitors of EV71. A potential drug candidate named NLD-22 exhibited excellent antiviral activity (with an EC₅₀ of 5.056 nM and a 100% protection rate for mice at a dose of 20 mg/kg) and low toxicity. NLD-22 had a favorable pharmacokinetic profile. High-resolution cryo-electron microscopy structural analysis confirmed NLD-22 bound to the hydrophobic pocket in VP1 to block viral infection. In general, NLD-22 was indicated to be a promising potential drug candidate for the treatment of HFMD.