Design, synthesis and antitubercular evaluation of novel 5,6-diphenyl-1,2,4-triazine-piperazine derivatives targeting mycobacterial dihydrofolate reductase: Original scientific article

Uday Thakkar; Moksh Shah; Pratik Khona; Harnisha Patel; Mange Ram Yadav; Salman Patel; Chanchal Singh; Renuka Bhamre; Afzal Nagani

doi:10.5599/admet.3322

Authors

Uday Thakkar Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0009-0007-5646-1198
Moksh Shah Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0009-0007-2586-1869
Pratik Khona Faculty of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0009-0005-4511-8875
Harnisha Patel Krishna School of Pharmacy, KPGU, Vadodara, Gujarat, India https://orcid.org/0000-0002-0474-2509
Mange Ram Yadav Faculty of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0000-0003-2020-5225
Salman Patel Purical Inc., Etobicoke, Canada https://orcid.org/0000-0001-9687-3479
Chanchal Singh Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0009-0000-6248-5013
Renuka Bhamre Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat, India https://orcid.org/0009-0008-1510-8993
Afzal Nagani Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat, India and and Research and Development Cell, Parul University, Vadodara, Gujarat, India https://orcid.org/0000-0002-9016-1507

DOI:

https://doi.org/10.5599/admet.3322

Keywords:

Antitubercular, density function theory, Mtb-DHFR inhibitor, molecular docking, molecular dynamic simulation

Abstract

Background and purpose: Tuberculosis (TB), a serious global health concern, continues to contribute to the global health burden, underscoring the urgent need to discover potent antitubercular agents. In the present study, a series of novel 5,6-diphenyl-1,2,4-triazine-piperazine derivatives were synthesized, and their potential for anti-tubercular activity was assessed. Experimental approach: The antitubercular potential of the synthesized compounds was assessed using the microplate alamar blue assay (MABA). Cytotoxicity studies were carried out on RAW 264.7 macrophages. To assess the mode of action of the synthesized compounds, docking analysis of the active compounds was performed on two key enzymes of Mycobacterium, decaprenylphosphoryl-β-D-ribose 2′-epimerase and Mycobacterium tuberculosis-dihydrofolate reductase (Mtb-DHFR). Furthermore, molecular dynamics simulations and density functional theory calculations were performed to validate the stability of the ligand–protein complexes and the electronic properties of the lead compounds. Key results: The results revealed promising anti-tubercular activity for the synthesized compounds. Among these, compounds 2-((5,6-Diphenyl-1,2,4-triazin-3-yl)thio)--1-(4-(4-fluorobenzoyl)piperazin-1-yl)ethan-1-one (FP3) and 2-((5,6-diphenyl-1,2,4-triazin-3-yl)thio)-1-(4-(4-methylbenzoyl) piperazin-1-yl)ethan-1-one (FP8) exhibited potent activity with an minimum inhibitory concentration of 1.6 µg mL⁻¹, along with promising cytotoxicity profiles against RAW 264.7 macrophage cells. Docking studies revealed potent docking scores compared to the standard, thereby confirming the involvement of the DHFR enzyme. Interaction analysis revealed stable hydrogen-bond interactions, π-π stacking, and hydrophobic interactions with the active-site residues of the DHFR enzyme. Additionally, molecular dynamics simulation validated the stability of the interactions and the structural integrity of the complexes, while density functional theory calculations supported the desirable electronic properties of the lead compounds. Conclusion: The combined results of the experiments and calculations validated the potential of FP3 and FP8 as DHFR-targeted antitubercular agents. The study highlights the potential of 5,6-diphenyl-1,2,4-triazine-piperazine derivatives as promising candidates for further anti-tubercular drug development.

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