Novel non-peptide lead structures for Bradykinin B2-receptor antagonists

A series of new non-peptide Bradykinin (BK) B2-receptor antagonists is reported. These new leads belong to a larger set including both commercially or otherwise available potential candidates found by proprietary database searches using 3D-pharmacophore models as query, and several bis-benzamidino compounds selected from our tryptase-like protease inhibitor library on the basis of topological considerations, derived from the same models. Some of these compounds show functional competitive antagonistic activity, inhibiting in vitro the BK-induced contraction of isolated guinea-pig ileum (GPI) and rat uterus with a pA2 up to 5.3 and 7.0, respectively. They display also binding affinity (IC50 up to 0.56 μM) to the BK B2-receptor in radioligand binding assays on GPI membrane preparations and on human IMR-90 fetal lung fibroblast cells expressing this receptor subtype. Furthermore, the results with the commercially available compounds, in some cases developed as therapeutics, show that the used 3D-pharmacophore model allows to predict to some certainty possible side actions of potential drugs.