3-Arylpropionylhydroxamic acid derivatives as Helicobacter pylori urease inhibitors: Synthesis, molecular docking and biological evaluation.

Helicobacter pylori urease is involved in several physiologic responses such as stomach and duodenal ulcers, adenocarcinomas and stomach lymphomas. Thus, inhibition of urease is taken for a good chance to treat H. pylori-caused infections, we have therefore focused our efforts on seeking novel urease inhibitors. Here, a series of arylpropionylhydroxamic acids were synthesized and evaluated for urease inhibition. Out of these compounds, 3-(2-benzyloxy-5-chlorophenyl)-3-hydroxypropionylhydroxamic acid (d24) was the most active inhibitor with IC50 of 0.15±0.05µM, showing a mixed inhibition with both competitive and uncompetitive aspects. Non-linear fitting of kinetic data gives kinetics parameters of 0.13 and 0.12µg·mL(-1) for Ki and Ki', respectively. The plasma protein binding assays suggested that d24 exhibited moderate binding to human and rabbit plasma proteins.

Novel 3-arylfuran-2(5H)-one-fluoroquinolone hybrid: design, synthesis and evaluation as antibacterial agent.

3-Arylfuran-2(5H)-one, a novel antibacterial pharmacophore targeting tyrosyl-tRNA synthetase (TyrRS), was hybridized with the clinically used fluoroquinolones to give a series of novel multi-target antimicrobial agents. Thus, twenty seven 3-arylfuran-2(5H)-one-fluoroquinolone hybrids were synthesized and evaluated for their antimicrobial activities. Some of the hybrids exhibited merits from both parents, displaying a broad spectrum of activity against resistant strains including both Gram-negative and Gram-positive bacteria. The most potent compound (11) in antibacterial assay shows MIC50 of 0.11µg/mL against Multiple drug resistant Escherichia coli, being about 51-fold more potent than ciprofloxacin. The enzyme assays reveal that 11 is a potent multi-target inhibitor with IC50 of 1.15±0.07µM against DNA gyrase and 0.12±0.04µM against TyrRS, respectively. Its excellent inhibitory activities against isolated enzymes and intact cells strongly suggest that 11 deserves to further research as a novel antibiotic.

Synthesis, molecular docking and kinetic properties of ß-hydroxy-ß-phenylpropionyl-hydroxamic acids as Helicobacter pylori urease inhibitors.

Inhibition of urease results in Helicobacter pylori growth arrest in the stomach, promoting urease as promising targets for gastrointestinal ulcer therapy. Twenty hybrid derivatives of flavonoid scaffold and hydroxamic acid, ß-hydroxy-ß-phenylpropionylhydroxamic acids, were therefore synthesized and evaluated against H. pylori urease. Biological evaluation of these compounds showed improved urease inhibition exhibiting micromolar to mid-nanomolar IC50 values. Most importantly, 3-(3-chlorophenyl)-3-hydroxypropionyl-hydroxamic acid (6g) exhibited high potency with IC50 of 0.083±0.004 µM and Ki of 0.014±0.003 µM, indicating that 6g is an excellent candidate to develop novel antiulcer agent. A mixture of competitive and uncompetitive mechanism was putatively proposed to understand the inconsistency between the crystallographic and kinetic studies for the first time, which is supported by our molecular docking studies.

3-Aryl-4-acyloxyethoxyfuran-2(5H)-ones as inhibitors of tyrosyl-tRNA synthetase: synthesis, molecular docking and antibacterial evaluation.

Thirty-eight 3-aryl-4-acyloxyethoxyfuran-2(5H)-ones were designed, prepared and tested for antibacterial activities. Some of them showed significant antibacterial activity against Gram-positive organism, Gram-negative organism and fungus. Out of these compounds, 4-(2-(3-chlorophenylformyloxy)ethoxy)-3-(4-chlorophenyl)furan-2(5H)-one (d40) showed the widest spectrum of activity with MIC50 of 2.0µg/mL against Staphylococcus aureus, 4.3µg/mL against Escherichia coli, 1.5µg/mL against Pseudomonas aeruginosa and 1.2µg/mL against Candida albicans. Our data disclosed that MIC50 values against whole cell bacteria are positive correlation with MIC50 values against tyrosyl-tRNA synthetase. Meanwhile, molecular docking of d40 into S. aureus tyrosyl-tRNA synthetase active site was also performed, and the inhibitor tightly fitting the active site might be an important reason why it has high antimicrobial activity.