In the present study, we attempted to develop novel class of Mycobacterium tuberculosis (Mtb) inhibitors by exploring the pharmaceutically underexploited enzyme targets which are majorly involved in cell wall biosynthesis of mycobacteria. For this purpose glutamate racemase was selected which racemizes d-glutamate from l-glutamate, a key step in peptidoglycan synthesis. Furthermore, enzyme is neither expressed nor its product, d-glutamate is produced in mammals, and hence inhibiting this enzyme will have no vulnerable effect in host organism. A library of our in-house compounds were screened against glutamate racemase using a biophysical technique; thermal shift assay and further by enzyme inhibition assay to identify Lead 1 molecule. Lead 1 optimization and expansion resulted in twenty four compounds. Among the synthesized compounds twelve compounds shown good enzyme inhibition than Lead 1 (IC₅₀ 20.07 ± 0.29 μM). Among all the compounds; compound 22 (IC₅₀ 1.1 ± 0.52 μM) showed potent non-competitive mode of inhibition in enzyme assay. Further showed good susceptibility (in replicating bacteria) of MIC 8.72 μM and bactericidal time dependant kill on dormant culture. It also exhibited significant activity in Mtb nutrient starvation model (2.5) and Mtb biofilm model (2.4) and in vivo M. marinum infected Zebra fish model studies (3.6) reduction at logarithmic scale.

在本研究中，我们试图通过探索主要参与分枝杆菌细胞壁生物合成的药物开发不足的酶靶标来开发新型的结核分枝杆菌（Mtb）抑制剂。用于此目的的谷氨酸消旋酶是选择了哪个外消旋化d从谷氨酸盐升谷氨酸盐，在肽聚糖合成中的关键步骤。此外，酶既不表达也不表达其产物，d谷氨酸在哺乳动物中产生，因此抑制该酶将不会对宿主生物产生脆弱的影响。使用生物物理技术筛选了我们内部化合物的库，以检测谷氨酸消旋酶；热转移测定，并进一步通过酶抑制测定来鉴定Lead 1分子。Lead 1的优化和扩展产生了24种化合物。在合成的化合物中，十二种化合物显示出比铅1更好的酶抑制作用（IC ₅₀ 20.07±0.29μM）。在所有化合物中；化合物22（IC ₅₀1.1±0.52μM）在酶分析中显示出有效的非竞争性抑制模式。进一步显示MIC 8.72μM具有良好的敏感性（在复制细菌中），并且对休眠培养具有杀菌时间依赖性。在对数尺度下，它在Mtb营养饥饿模型（2.5）和Mtb生物膜模型（2.4）以及体内感染了海藻的斑马鱼模型研究（3.6）中也显示出显着的活性。