Methionine aminopeptidases (MetAPs) are attractive drug targets due to their essential role in eukaryotes as well as prokaryotic cells. In this study, biochemical assays were performed on newly synthesized Isatin-pyrazole hydrazones (PS1–14) to identify potent and selective bacterial MetAPs inhibitors. Compound PS9 inhibited prokaryotic MetAPs, i.e., MtMetAP1c, EfMetAP1a and SpMetAP1a with Ki values of 0.31, 6.93 and 0.37 µM, respectively. Interestingly, PS9 inhibited the human analogue HsMetAP1b with Ki (631.7 µM) about ten thousand-fold higher than the bacterial MetAPs. The in vitro screening against Gram-positive (Enterococcus faecalis, Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli) bacterial strains also exhibited their antibacterial potential supported by minimum bactericidal concentration (MBC), disk diffusion assay, growth curve and time-kill curve experiments. Additionally, PS6 and PS9 had synergistic effects when combined with ampicillin (AMP) and ciprofloxacin (CIP) against selective bacterial strains. PS9 showed no significant cytotoxic effect on human RBCs, HEK293 cells and Galleria mellonella larvae in vivo. PS9 inhibited the growth of multidrug-resistant environmental isolates as it showed the MIC lower than the standard drugs used against selective bacterial strains. Overall, the study suggested PS9 could be a useful candidate for the development of antibacterial alternatives.
蛋氨酸氨肽酶(MetAPs)在真核细胞和原核细胞中都发挥着重要作用,因此是极具吸引力的药物靶标。本研究对新合成的异汀吡唑肼(PS1-14)进行了生化试验,以确定强效且具有选择性的细菌 MetAPs 抑制剂。化合物 PS9 可抑制原核生物 MetAPs,即 MtMetAP1c、EfMetAP1a 和 SpMetAP1a,其 Ki 值分别为 0.31、6.93 和 0.37 µM。有趣的是,PS9 对人类类似物 HsMetAP1b 的抑制作用 Ki(631.7 µM)比细菌 MetAPs 高出约一万倍。针对革兰氏阳性(粪肠球菌、枯草芽孢杆菌和金黄色葡萄球菌)和革兰氏阴性(铜绿假单胞菌、肺炎克雷伯氏菌和大肠埃希氏菌)细菌菌株的体外筛选也显示了它们的抗菌潜力,最低杀菌浓度(MBC)、盘扩散试验、生长曲线和时间杀伤曲线实验都证明了这一点。此外,当 PS6 和 PS9 与氨苄西林(AMP)和环丙沙星(CIP)联合使用时,对选择性细菌菌株具有协同作用。PS9 在体内对人类红细胞、HEK293 细胞和灰飞虱幼虫没有明显的细胞毒性作用。PS9 能抑制耐多药环境分离菌株的生长,因为它的 MIC 值低于针对选择性细菌菌株的标准药物。总之,研究表明 PS9 可作为开发抗菌替代品的有用候选物质。