Novel 2-phenyl-4,5,6,7-tetrahydro[b]benzothiophene analogues as selective COX-2 inhibitors: Design, synthesis, anti-inflammatory evaluation, and molecular docking studies.

A series of 2-phenyl-4,5,6,7-tetrahydro[b]benzothiophene derivatives were synthesized and evaluated for in vitro COX inhibitory potential. Within the series, compounds 4a, 4j, 4k, and 4q were identified as potential and selective COX-2 inhibitors with COX-2 IC50 in 0.31-1.40µM range; COX-2 selectivity index (SI)=48.8-183.8 range and they showed percent PGE-2 inhibitory activity in the range of 25.4-46.9. Further, compounds 4a, 4j, 4k and 4q displayed potent anti-inflammatory activity with percentage rise in paw volume ranging from 21.1-30.5 at 180min, while celecoxib demonstrated 19.6 percentage rise at the same dose at 180min in carrageenan-induced rat paw edema assay. Cell viability via MTT assay showed no cytotoxicity up to 80µM concentrations. Molecular docking study of potent compounds in the series showed Gscore comparable to celecoxib with similar binding orientation for the COX-2 active site which also corroborates the observed in vitro COX-2 inhibition.