Design, synthesis, and biological activity studies on benzimidazole derivatives targeting myeloperoxidase

Myeloperoxidase (MPO) plays a key role in human antimicrobial system by oxidizing vital molecules of microorganisms in phagolysosomes through produced hypochlorous acid (HOCl). However, MPO can be released outside the phagocyte and produces reactive intermediates leading to tissue damage. MPO, as a local mediator of tissue damage, has been associated with inflammatory diseases such as renal injury, multiple sclerosis, cardiovascular and neurodegenerative diseases. Therefore, the enzyme currently draws attention as a potential therapeutic target. In this study, isomeric 1,3-dihydro-2H-benzo[d]imidazole-2-thione derivatives having amide, hydrazide and hydroxamic acid groups either on nitrogen or on sulphur atom were designed and their inhibitory activity was determined on chlorination and peroxidation cycles of MPO. Among the compounds, 2-(2-thioxo-2,3-dihydro-1H-benzo[d]imidazole-1-yl)acetohydrazide(C19) was found as the most active inhibitor on both cycles.