Table 1.

Antiviral activity against EV71, cytotoxicity, and selectivity index (SI) of pimprinine, pimprinethine, WS-30581 A and WS-30581 B in RD cells

Tested compound	CC50 a (μM)	EC50 b (μM)	EC90 c (μM)	SI d
Pimprinine	1455 ± 27e	89 ± 18	149 ± 12	16
Pimprinethine	835 ± 20	35 ± 4	42 ± 3	24
WS-30581 A	363 ± 13	16 ± 1	26 ± 6	23
WS-30581 B	229 ± 10	11 ± 3	18 ± 2	21
Ribavirinef	1230 ± 355	102 ± 68	136 ± 49	12

^aCC50, compound concentration required to reduce cell viability by 50%.

^bEC50, compound concentration required to achieve 50% protection from virus-induced cytopathogenicity.

^cEC90, compound concentration required to achieve 90% virus yield reduction.

^dSI (selectivity index), ratio CC50/EC50.

^eValues represent the mean ± SD of three independent experiments.

^fRibavirin, used as a positive control.