Targeting methionyl tRNA synthetase: design, synthesis and antibacterial activity against Clostridium difficile of novel 3-biaryl-N-benzylpropan-1-amine derivatives.

The synthesis of a series of benzimidazole-N-benzylpropan-1-amines and adenine-N-benzylpropan-1-amines is described. Subsequent evaluation against two strains of the anaerobic bacterium Clostridium difficile was performed with three amine derivatives displaying MIC values of 16 µg/mL. Molecular docking studies of the described amines determined that the amines interact within two active site pockets of C. difficile methionyl tRNA synthetase with methoxy substituents in the benzyl ring and an adenine biaryl moiety resulting in optimal binding interactions.

In-silico Leishmania target selectivity of antiparasitic terpenoids.

Neglected Tropical Diseases (NTDs), like leishmaniasis, are major causes of mortality in resource-limited countries. The mortality associated with these diseases is largely due to fragile healthcare systems, lack of access to medicines, and resistance by the parasites to the few available drugs. Many antiparasitic plant-derived isoprenoids have been reported, and many of them have good in vitro activity against various forms of Leishmania spp. In this work, potential Leishmania biochemical targets of antiparasitic isoprenoids were studied in silico. Antiparasitic monoterpenoids selectively docked to L. infantum nicotinamidase, L. major uridine diphosphate-glucose pyrophosphorylase and methionyl t-RNA synthetase. The two protein targets selectively targeted by germacranolide sesquiterpenoids were L. major methionyl t-RNA synthetase and dihydroorotate dehydrogenase. Diterpenoids generally favored docking to L. mexicana glycerol-3-phosphate dehydrogenase. Limonoids also showed some selectivity for L. mexicana glycerol-3-phosphate dehydrogenase and L. major dihydroorotate dehydrogenase while withanolides docked more selectively with L. major uridine diphosphate-glucose pyrophosphorylase. The selectivity of the different classes of antiparasitic compounds for the protein targets considered in this work can be explored in fragment- and/or structure-based drug design towards the development of leads for new antileishmanial drugs.

Preparation, antibacterial evaluation and preliminary structure-activity relationship (SAR) study of benzothiazol- and benzoxazol-2-amine derivatives.

In this study, a novel benzothiazol- and benzooxazol-2-amine scaffold with antibacterial activity was designed and synthesized. Preliminary structure-activity relationship analysis displayed that compound 8t with a 5,6-difluorosubstituted benzothiazole was found to be a potent inhibitor of Gram-positive pathogens, and exhibited some potential against drug-resistant bacteria and without cytotoxicity in therapeutic concentrations. In addition, molecular docking studies indicated that Staphylococcus aureus methionyl-tRNA synthetase might be the possible target of these compounds. Taken together, the present study provides an effective entry to the synthesis of a good lead for subsequent optimization and a new small molecule candidate drug for antibacterial therapeutics.