Table 1.

The structures of isoxazole derivatives and the IC₅₀ values against COX enzymes

Name	R1	R2	IC50 COX-1 (µM)	IC50 COX-2 (µM)	Selectivity index
A1	H	H	0.839 ± 0.04	1.214 ± 0.78	0.69
A2	H	3-OCH3, 4-OCH3, 5-OCH3	0.269 ± 0.17	3.949 ± 1.02	0.07
A3	H	3- OCH3, 5-OCH3	0.122 ± 0.11	0.310 ± 0.25	0.39
A4	H	3-OCH3, 4-OCH3	0.076 ± 0.06	0.258 ± 0.28	0.29
A5	H	4-t-butyl	0.312 ± 0.16	0.486 ± 0.01	0.65
A6	4-F	H	0.140 ± 0.05	0.218 ± 0.11	0.6418
A7	4-F	3-OCH3, 4-OCH3, 5-OCH3	0.350 ± 0.05	0.346 ± 0.24	1.0113
A8	4-F	3-OCH3,5-OCH3	0.317 ± 0.02	0.878 ± 0.47	0.3618
A9	4-F	3-OCH3, 4-OCH3	0.335 ± 0.07	0.829 ± 0.15	0.4047
A10	4-F	4-t-butyl	0.126 ± 0.10	0.370 ± 0.08	0.3403
A11	4-F	2-OCH3, 4-Cl, 5-OCH3	0.478 ± 0.21	0.334 ± 0.03	0.5604
A12	2-Cl	3-OCH3,5-OCH3	0.413 ± 0.19	0.293 ± 0.11	1.4117
A13	2-Cl	3-OCH3, 4-OCH3	0.064 ± 0.02	0.013 ± 0.01	4.6341
A14	2-Cl	2-OCH3, 5-OCH3	0.077 ± 0.01	0.376 ± 0.21	0.2066
B1	2-Cl	–	1.210 ± 0.55	0.856 ± 0.15	1.414454
B2	4-F	–	0.702 ± 0.28	0.033 ± 0.07	20.72017
B3	H	–	0.668 ± 0.08	1.040 ± 0.85	0.642553
Ketoprofen	–	–	0.043 ± 0.02	0.066 ± 0.05	0.643249
Celecoxib	–	–	1.479 ± 0.47	0.004 ± 0.003	369.75