Indumathi, L (2021) Design, Synthesis and Anti Tubercular Screening of Triazolyl Pyrazoles as Possible MTB–CYP51 Inhibitors. Masters thesis, College of Pharmacy, Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore.
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Abstract
The present work was focused on the design, docking, synthesis, and evaluation of the antitubercular activity of triazole-linked pyrazole derivatives as possible CYP-51 (sterol 14α-demethylase) inhibitors. PHASE I - IN-SILICO STUDIES: • Selection of the target: CYP-51 (sterol 14α-demethylase) was selected as the drug target for the anti-tubercular activity. The corresponding enzyme was obtained from the RCSB protein data bank (PDB ID:1EA1). • Selection of lead by virtual screening: Virtual screening was performed by iGEMDOCK v.2. Fifty hits were obtained from the ZINC database, from which triazole and pyrazole were selected as the lead for inhibiting CYP-51 (sterol 14α-demethylase). • Lead optimization: The six modified ligands TP1-TP6 were subjected to in-silico lead optimization. Lead optimization was done by observing in-silico ADME studies and computation of drug-like properties. Lead optimization revealed that all the six selected derivatives possess good ADME properties and hence were eligible for further study. The ligands were optimized for evaluating oral bioavailability by utilizing the Molinspiration server and SWISSadme server. • Docking: The optimized leads were subjected to docking studies using Autodock4.2 and the interactions of the derivatives with active sites of the enzyme were studied. The derivatives were subjected to interaction with CYP-51. Fluconazole was used as standard ligand. The binding energy was found to be superior for all the compounds when compared to the standard (fluconazole). Among the triazolyl pyrazole derivatives, TP1, TP4, TP3, TP2 showed maximum binding energies, -8.93, -8.68, -8.38, -8.26 kcal/mol respectively. They were interacting well with the active sites on the enzyme i.e., Tyr 76, Met 79, Phe 83, Arg 96, and Met 99. PHASE II - SYNTHESIS AND PHYSICAL CHARACTERIZATION: • Synthesis of the designed compounds: In this present work, six new compounds were synthesized. In the first scheme triazole amine and its derivatives were synthesized by the reaction of thiocarbohydrazide with substituted and unsubstituted benzoic acid. Two steps were involved in the scheme 2. The first step involves the synthesis of 5-Methyl-2-phenyl-2, 4-dihydro-3H-pyrazole-3-one by the reaction of phenylhydrazine with ethyl acetoacetate. The second step involves the synthesis of 5-Chloro-3-methyl-1-phenyl-1Hpyrazole-4-carbaldehyde. The resulting compound from the first step was treated with phosphorus oxychloride and dimethylformamide. Scheme 3 involves the synthesis of triazolyl pyrazole derivatives. Schiff bases were prepared from triazole amine derivatives with pyrazole aldehyde to obtain desired products. • Physical characterization: The melting point of newly synthesized compounds were determined. Rf values were determined by fixing various suitable solvent system on precoated silica gel G plates. The solvent system used was Acetone: Benzene (2:8). PHASE III: SPECTRAL CHARACTERIZATION: The structures of the synthesized compounds were established on the basis of UV, IR, 1H NMR, and MASS spectral data. PHASE IV: ANTI MYCOBACTERIAL SCREENING: MICROPLATE ALAMAR BLUE ASSAY (MABA) METHOD: The anti-tubercular activity was performed by microplate alamar blue assay method by using mycobacterium tuberculosis H37Rv strain. All the derivatives of triazolyl pyrazoles (TP1 to TP6) were found to inhibit the growth of Mycobacterium tuberculosis. The compound TP1 (2Cl-5NO2 triazolyl pyrazole) had shown minimum inhibitory concentration at 50 μg/ml and TP5 (4-NO2 triazolyl pyrazole) showed MIC of 1.6 μg/ml. CONCLUSION: The present study has proved to be a tool in minimizing the tedious process of drug discovery process over the traditional methods of discovery. Virtual screening was utilized for filtering the compounds and selecting the lead compounds. The In-silico ADME & drug-likeness scores of the ligands showed the compound to be promising as a good orally bioactive drug. The binding energy obtained from the docking study further confirmed the affinity of the selected leads towards the enzyme, CYP-51 (sterol 14α-demethylase) from Mycobacterium tuberculosis. Various triazolyl imino pyrazole derivatives were synthesized with good yield utilizing three schemes. The structure of the synthesized compounds were confirmed by melting point, TLC, UV, IR, NMR and mass spectra. The compounds were screened for antimycobacterial activity which establishes the correlation of activity with the docking study. The present study includes the design, docking, synthesis and screening of various triazole incorporated pyrazole imines as possible CYP-51 inhibitors and the design has paved the way to establish the lead triazolyl pyrazole as antimycobacterial drug choice. Among the synthesized compounds, 2-chloro5-nitro-triazolyl pyrazole imine was found to be potent as CYP-51 inhibitor due to superior dock result and biological activity result. The docking study reveals that the triazolyl imino prazole has excellent interaction with CYP51, and therefore can be probed as possible MtbCYP-51 inhibitors. FUTURE PERSPECTIVE: Since the most potential derivative was the chloro and nitro substituted triazolyl imino pyrazole derivative, more focus can be given on electron withdrawing substituents for future synthesis. The present novel derivatives are found to exhibit antimycobacterial activity, the mechanism of action can be confirmed by performing enzyme inhibitory assay as a future perspective.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | 261915102 |
| Uncontrolled Keywords: | Design, Synthesis, Anti Tubercular Screening, Triazolyl Pyrazoles, MTB–CYP51 Inhibitors. |
| Subjects: | PHARMACY > Pharmaceutical Chemistry |
| Depositing User: | Subramani R |
| Date Deposited: | 02 Nov 2022 17:20 |
| Last Modified: | 03 Nov 2022 13:33 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/20915 |
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