RESUMO
Thirty three derivatives of 2-substituted 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine analogues were synthesized by molecular modification of a reported antimycobacterial molecule (GSK163574A). Compounds were evaluated in vitro against actively replicative and nutrient starved non-replicative Mycobacterium tuberculosis (MTB), enzymatic screening and cytotoxicity against RAW 264.7 cell line. Among the compounds, 2-ethyl-N-phenethyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine (5c) was found to be the most active compound against non-replicative MTB with 2.7 log reduction of bacteria at 10µg/mL and was more potent than isoniazid (1.2 log reduction) and rifampicin (2.0 log reduction) at same dose level. Compound 5c also showed activity against MTB alanine dehydrogenase enzyme with IC50 of 1.82±0.42µM and showed 25% cytotoxicity against RAW 264.7 cell line at 50µg/mL.
Assuntos
Alanina Desidrogenase/antagonistas & inibidores , Antituberculosos/farmacologia , Inibidores Enzimáticos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Pirimidinas/farmacologia , Tiofenos/farmacologia , Alanina Desidrogenase/metabolismo , Antituberculosos/síntese química , Antituberculosos/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/enzimologia , Pirimidinas/síntese química , Pirimidinas/química , Relação Estrutura-Atividade , Tiofenos/síntese química , Tiofenos/químicaRESUMO
Mycobacterium tuberculosisl-alanine dehydrogenase (MTB l-AlaDH) is one of the important drug targets for treating latent/persistent tuberculosis. In this study we used crystal structure of the MTB l-AlaDH bound with cofactor NAD(+) as a structural framework for virtual screening of our in-house database to identified new classes of l-AlaDH inhibitor. We identified azetidine-2,4-dicarboxamide derivative as one of the potent inhibitor with IC50 of 9.22±0.72µM. Further lead optimization by synthesis leads to compound 1-(isonicotinamido)-N(2),N(4)-bis(benzo[d]thiazol-2-yl)azetidine-2,4-dicarboxamide (18) with l-AlaDH IC50 of 3.83±0.12µM, 2.0log reduction in nutrient starved dormant MTB model and MIC of 11.81µM in actively replicative MTB.