The inhibition effect of lycorine on RD cells. A, IC50 of lycorine for inhibiting EV71 infection was determined by the reduction of CPE on RD cells. B, the viral copy number was detected by qRT-PCR in the RD cells treated with lycorine at a dose of 1 μg/ml. The data are expressed as mean values of three independent experiments ± SD, *: p < 0.05. C, CPE of EV71-infected RD cells at 3 dpi were observed under light microscope (100×).