Synthesis, QSAR, and molecular dynamics simulation of amidino-substituted benzimidazoles as dipeptidyl peptidase III inhibitors

A molecular modeling study has been performed on a series of 16 benzimidazole-based inhibitors of human dipeptidyl peptidase III (DPP III). Eight of these were novel compounds synthesized in excellent yields using green chemistry approach. This study aims at elucidating the structural features of benzimidazole derivatives required for the antagonism of human DPP III activity using Quantitative Structure-Activity Relationship (QSAR) analysis, and at understanding the mechanism of one of the most potent inhibitor bindings into the active site of this enzyme, namely by molecular dynamics (MD) simulations. The best model obtained includes S3K and RDF045m descriptors, which have explained 89.4 % of inhibitory activity. The depicted moiety for the strong inhibition activity matches the structure of the most potent compound. MD simulation has revealed the importance of imidazolinyl and phenyl groups in the mechanism of binding into the active site of human DPP III