Table 2. Anti-H5N1 activities of benzothiophene-based benzenesulfonamide derivatives 12a–s in MDCK cells ^a .

Entry	Cmpd	Core structure	R	EC50 b (μM) AMD-sensitive H5N1	EC50 c (μM) AMD-resistant H5N1	CC50 d (μM)	SI e
1	12a		4-NO2	1.38 ± 0.29	NA	>191.45	>138.7
2	12b		4-CN	20.28 ± 8.34	NA	122.41 ± 32.59	6.0
3	12c		4-F	3.42 ± 0.81	NA	98.64 ± 29.25	28.8
4	12d		4-Cl	1.98 ± 0.68	NA	69.56 ± 15.39	35.1
5	12e		4-Br	7.22 ± 1.60	NA	87.11 ± 21.71	12.1
6	12f		4-CF3	38.56 ± 14.73	NA	94.78 ± 14.27	2.5
7	12g		4-Me	10.49 ± 3.78	NA	>210.13	>20.0
8	12h		2-F	NA f	NA	— g	— h
9	12i		3-F	NA	NA	—	—
10	12j		4-COCH3	12.04 ± 3.85	NA	>193.09	>16.0
11	12k		4-NO2	49.97 ± 14.87	NA	>191.45	>3.8
12	12l		4-CN	NA	NA	—	—
13	12m		4-F	NA	NA	—	—
14	12n		4-Cl	NA	NA	—	—
15	12o		4-Br	40.70 ± 12.11	NA	>174.47	>4.3
16	12p		4-CF3	44.83 ± 16.51	NA	>179.60	>4.0
17	12q		4-Me	41.96 ± 13.74	NA	>210.13	>5.0
18	12r		2-F	NA	NA	—	—
19	12s		3-F	NA	NA	—	—
20	AMD			0.43 ± 0.13	NA	>100.00	>235.3
21	Oseltamivir phosphate			0.39 ± 0.10	0.34 ± 0.02	>163.26	>418.6

^aAll data were obtained from at least three independent experiments.

^bEC₅₀, concentration that effectively inhibited amantadine-sensitive H5N1 virus plaque formation by 50%.

^cEC₅₀, concentration that effectively inhibited amantadine-resistant H5N1 virus plaque formation by 50%.

^dCC₅₀, concentration that inhibited cell growth by 50% compared with control cultures.

^eSelectivity index (SI) was determined for the effective compounds by dividing CC₅₀ by EC₅₀ (amantadine-sensitive H5N1 virus).

^fNA: no activity (EC₅₀ > 100 μM).

^g—: no detection.

^h—: no selectivity index.