Discovery and structure-activity relationship studies of 2-benzylidene-2,3-dihydro-1H-inden-1-one and benzofuran-3(2H)-one derivatives as a novel class of potential therapeutics for inflammatory bowel disease.

To develop effective therapeutics for inflammatory bowel disease (IBD), 2-benzylidene-2,3-dihydro-1H-inden-1-one and benzofuran-3(2H)-one derivatives, were designed and synthesized and their structure-activity relationships (SAR) were investigated. Compounds 7, 25, 26, 32, 39, 41, 52, 54, and 55 showed potent inhibitory effect (>70%) on the TNF-α-induced adhesion of monocytes to colon epithelial cells, which is one of the hallmark events leading to IBD. Such inhibitory activity of the compounds correlated with their suppressive activities against the TNF-α-induced production of ROS; ICAM-1 and MCP-1 expression, critical molecules involved in monocyte-epithelial adhesion; and NF-κB transcriptional activity. In addition, compounds 41 and 55 significantly suppressed the lipopolysaccharide (LPS)-induced expression of the TNF-α gene, with compound 55 showing better efficacy. This inhibition of TNF-α expression by compounds 41 and 55 corresponded to their additional inhibitory activity against AP-1 transcriptional activity, which is another transcription factor required for high level TNF-α expression. The strong inhibitory activity of compound 55 against an in vivo colitis model was confirmed by its dose-dependent inhibitory activity in a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis, demonstrating compound 55 as a new potential candidate for the development of therapeutics against IBD.