Fig. 4 Effects of quercetin on EV71 2Apro and 3Dpol activity. a Effect of quercetin on 2Apro activity of EV71. RD cells were transfected with pEGFP-C1-2A or pEGFP-C1-2Amut (C110S) and reporter plasmid pCMV-FLuc, and then quercetin was added or not. After 24 h, the firefly luciferase activities were analysed. The data of three independent experiments are presented as the mean ± the standard deviation. b Effect of quercetin on EV71 3D RdRp primer extension assay. RNA polymerase assays contained poly (rA) 300, EV71 3Dpol, UTP, and [α-32P] UTP with or without quercetin (10 and 100 μM), the radioactivity was measured. The experiments were performed three times and the representative result was shown