Table 2.

Inhibitory activity of Chinese herbs extracts (1–5) on A(H1N1) influenza virus by CPE assay

Sample No.	EC50a	CC50b	MNCCc	SId
1	7.7	184.3	30	24
2	1.8	779.2	300	438
3	8.1	478.4	100	59
4	7.2	97.0	30	14
5	14.1	744.3	300	53
Ribavirin	3.2	> 100	—e	> 31
Zanamivir	> 90.4	> 1506.0	> 301.2	17

^aEC₅₀: Effective concentration required to protect 50% of cells; ^b CC₅₀: Median (50%) cytotoxic concentration in MDCK cells; ^c MNCC: Maximal non-cytotoxic concentration in MDCK cells, values in μg/mL; ^d SI:Selectivity index, CC₅₀/EC₅₀.^e: not test