Department of Pharmacy

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    Exploration of quinoxaline triazoles as antimycobacterial agents: design, synthesis and biological evaluation
    (Elsevier, 2025-06) Murugesan, Sankaranarayanan
    In this work, novel 2-substituted-3-((1-substituted-1H-1,2,3-triazol-4-yl) methoxy) quinoxaline analogues were designed, synthesized, and various analytical techniques, viz., 1H NMR, 13C NMR, and Mass spectrometry, were deployed in the structure confirmation of the final compounds. Synthesized derivatives were evaluated for their antimycobacterial activity against Mycobacterium tuberculosis (Mtb) H37Rv. Target molecules mainly consist of methyl substituent in the second position of quinoxaline moiety (QM series) or phenyl substituent in the second position (QP series). Among the forty-two compounds synthesized and evaluated for anti-mycobacterial activity, the MIC values ranged between 5.58 μg/mL to >100 μg/mL. Among QM series compounds, QM7, with MIC 5.58 μg /mL, was the most active compound. Among the QP series derivatives, the intermediate QP-Acy with MIC 23.39 μg /mL was the most promising. Most of the analogues tested in the QP series are less potent than the QM series. All the synthesized molecules showed good drug-likeness when evaluated using the SWISS ADME tool. QM7 was evaluated for docking studies using the crystal structure of enoyl-acyl carrier (INH-A) enzyme PDB: 4TZK, and it showed significant docking scores and interactions. MD simulations were carried out to assess the stability of the protein QM7 complex. Single crystals were grown for QM1, QM6, and QPb from these forty-two compounds, and their structures were solved using OLEX. The corresponding CCDC numbers for these compounds are 2,388,310, 2,388,309, and 2,388,291, respectively.
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    Design, synthesis, and biological evaluation of (E)-3-amino-N′-substituted benzylidene-6-chloropyrazine-2-carbohydrazide derivatives as anti-mycobacterial agents
    (Elsevier, 2025-12) Murugesan, Sankaranarayanan
    Pyrazinamide is a powerful sterilizing agent that reduces the treatment duration required to cure tuberculosis and works synergistically with both new and existing anti-tuberculosis drugs. Thirty-one derivatives of (E)-3-amino-N′-substituted benzylidene-6-chloropyrazine-2-carbohydrazide (20a-20ae) were designed and synthesized. The structures of these compounds were confirmed through various analytical methods, such as 1H NMR, 13C NMR, and mass spectrometry. To better understand the arrangement of atoms and confirm the structures, single crystals of 20 m and 20aa were grown and analyzed. The final derivatives, 20a-20ae, were evaluated for their anti-mycobacterial activity against the Mycobacterium tuberculosis (M.tb) H37Ra strain using the Microplate Alamar Blue Assay (MABA). Among all the synthesized compounds tested, 20 m and 20s showed potent activity with a minimum inhibitory concentration (MIC) of 3.13 μg/mL (8.66 μM and 11.37 μM, respectively). 20q and 20r also displayed significant anti-TB activity with an MIC of 6.25 μg/mL (23.66 μM and 21.47 μM, respectively). The MIC values of the remaining compounds ranged from 12.5 to >50 μg/mL (34.62 μM to 172.96 μM). To further evaluate the binding interaction within the active site of the enzyme aspartate decarboxylase (PanD) from M. tb (PDB: 6P02), a molecular docking analysis of compound 20s was performed. Finally, 100 ns molecular dynamics simulations were carried out to comprehend the stability, conformation, and intermolecular interactions of the co-crystal ligand and the highly active compound 20s with the selected target protein. Further, in order to better understand bacterial resistance and pathogenesis and to create efficient treatments against significant drug-resistant pathogens, in vitro anti-mycobacterial activity of the compounds with MIC ≤12.5 μg/mL (43.24 μM) was assessed for their effectiveness against the ESKAPE group of pathogens using the MABA method. Results indicate that 20e exhibited the most promising activity with an MIC of 50 μg/mL (172.9 μM) against Staphylococcus aureus among the ESKAPE group of pathogens.
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    Discovery of novel chromone and acrylate-based pancreatic lipase inhibitors: Molecular modelling, synthesis, and in vitro evaluation for the treatment of obesity
    (Wiley, 2024-01) Paul, Atish Tulshiram
    By the optimization of previously established pancreatic lipase (PL) inhibitory lead, we have developed novel chromone-containing analogues with embedded acrylate fragment as potential PL inhibitors. The analogues were designed by considering the structural features required for binding at the active site of PL enzyme with the utilization of molecular docking study. An optimized synthetic scheme was utilized for the synthesis of designed analogues of prototypes 1&2. Through in vitro PL inhibitory screening, three analogues namely, 5fj, 5gj and 9a were identified as potent PL inhibitory leads with IC50 values of 4.92, 4.23 and 3.32 μM, respectively. The protein binding of analogue 9a was analysed by fluorescence quenching study and it was found to bind at one binding site with a binding constant of 1.93 × 105 L mol−1. Analogue 9a also exhibited a competitive inhibitory mechanism with Ki value of 1.601 μM. In future, the potent lead 9a can be optimized to get a comparable or more potential PL inhibitory activity than marketed drugs.
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    Computational insights into human UCP1 activators through molecular docking, MM-GBSA, and molecular dynamics simulation studies
    (Elsevier, 2024-12) Paul, Atish Tulshiram
    The prevalence of obesity is rapidly increasing worldwide. Brown adipose tissue activates uncoupling protein 1 (UCP1) to generate heat through bypassing ATP synthesis, offering a potential target for obesity treatment. Targeting UCP1 activation to induce thermogenesis through small molecules presents a promising approach for obesity management. In this study, molecular docking of UCP1 activators, using 2,4-dinitrophenol (DNP) as a reference ligand (PDB ID: 8J1N, docking score: −5.343 kcal/mol), identified seven top-scoring compounds: naringin (-7.284 kcal/mol), quercetin (-6.661 kcal/mol), salsalate (-6.017 kcal/mol), rhein (-5.798 kcal/mol), mirabegron (-5.535 kcal/mol), curcumin (-5.479 kcal/mol), and formoterol (-5.451 kcal/mol). Prime MM-GBSA calculation of the top-scored molecule (i.e., naringin) in the docking study showed ΔGBind of −70.48 kcal/mol. Key interactions of these top 7 activators with UCP1 binding pocket residues Trp280, Arg276, Glu190, Arg83, and Arg91 were observed. Molecular dynamics simulations performed for 100 ns confirmed complex stability, with RMSD values below 6 Å. Additionally, most activators showed favorable intestinal absorption (>90 %) and lipophilicity (LogP 2–4), with pKa values supporting their pharmacological potential as UCP1-targeting therapeutics for obesity. These findings provide a foundation for designing potent UCP1 activators by integrating docking scores, interaction profiles, statistical profiles from MD simulations, and physicochemical assessments to develop effective anti-obesity therapies.
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    Synthesis, molecular modelling and biological evaluation of novel benzyloxy substituted indolyl oxoacetamides as potent pancreatic lipase inhibitors
    (Springer, 2025-08) Paul, Atish Tulshiram
    A series of 21 indolyl oxoacetamide analogues with benzyloxy-substituents were designed, synthesized and characterized using 1H NMR (Nuclear Magnetic Resonance), 13C NMR, and HRMS (High Resolution Mass Spectrometry) analysis. All the analogues were tested for inhibitory activity against pancreatic lipase. Two analogues, 9f and 10f, exhibited significant activity (IC50 of 2.89 and 2.50 µM, respectively), comparable to the standard drug, orlistat (IC50 = 0.99 µM). The potent analogues 10f and 9f exhibited significant binding affinity for pancreatic lipase (-170.222 kcal mol− 1 and − 153.547 kcal mol− 1). Additionally, both the potent analogues exhibited crucial interaction with Ser 152 and His 263 residues in the PL active site via hydrogen bonding. Molecular dynamics (MD) simulation was performed on the ligand-receptor complex of potent analogue (10f) for 200 ns. The molecule was stabilized by extending the π-π interactions with Phe 77 and Phe 215 of the active site lid domain due to benzyloxy substitution. Toxicity profile prediction indicated that all the analogues were non-hepatotoxic, unlike orlistat.
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    Identification of synthetically tractable MERS-CoV main protease inhibitors using structure-based virtual screening and molecular dynamics potential of mean force (PMF) calculations
    (Taylor & Francis, 2023-11) Sundriyal, Sandeep
    The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a potentially lethal infection that presents a substantial threat to health, especially in Middle East nations. Given that no FDA-approved specific therapy for MERS infection exists, designing and discovering a potent antiviral therapy for MERS-CoV is crucial. One pivotal strategy for inhibiting MERS replication is to focus on the viral main protease (Mpro). In this study, we identify potential novel Mpro inhibitors employing structure-based virtual screening of our recently reported Ugi reaction-derived library (URDL) consisting of cherry-picked molecules from the literature. The key features of the URDL library include synthetic tractability (1–2 pot synthesis) of the molecules scaffold and unexplored chemical space. The hits were ranked based on the docking score, MM-GBSA free energy of binding, and the interaction pattern with the active site residues. A molecular dynamics (MD) simulation study was performed for the first two top-ranked compounds to analyze the stability and free binding energy based on the molecular mechanics Poisson-Boltzmann surface area. The potential mean force calculated from the steered molecular dynamics (SMD) simulations of the hits indicates improved H-bond potential, enhanced conformational stability, and binding affinity toward the target, compared to the cocrystallized ligand. The discovered hits represent novel synthetically tractable scaffolds as potential MERS-CoV Mpro inhibitors.
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    Computational search for potential covid-19 drugs from ayurvedic medicinal plants to identify potential inhibitors against sars-cov-2 targets
    (Bentham Science, 2023-02) Murugesan, Sankaranarayanan
    To date, very few small drug molecules are used for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has been discovered since the epidemic commenced in November 2019. SARS-CoV-2 RdRp and spike protein are essential targets for drug development amidst whole variants of coronaviruses. Objective: This study aims to discover and recognize the most effective and promising small molecules against SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and spike protein targets through molecular docking screening of 39 phytochemicals from five different Ayurveda medicinal plants. Methods: The phytochemicals were downloaded from PubChem, and SARS-CoV-2 RdRp and spike protein were taken from the protein data bank. The molecular interactions, binding energy, and ADMET properties were analyzed. Results: Molecular docking analysis identified some phytochemicals, oleanolic acid, friedelin, serratagenic acid, uncinatone, clemaphenol A, sennosides B, trilobine and isotrilobine from ayurvedic medicinal plants possessing greater affinity against SARS-CoV-2-RdRp and spike protein targets. Two molecules, namely oleanolic acid and sennosides B, with low binding energies, were the most promising. Furthermore, based on the docking score, we carried out MD simulations for the oleanolic acid and sennosides B-protein complexes. Conclusion: Molecular ADMET profile estimation showed that the docked phytochemicals were safe. The present study suggested that active phytochemicals from medicinal plants could inhibit RdRp and spike protein of SARS-CoV-2.
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    Inspection of in-house designed novel thiochromone amino-acid conjugate derivatives as Lm-NMT inhibitor – An in-silico analysis
    (Elsevier, 2023-03) Murugesan, Sankaranarayanan
    Leishmaniasis is a complex neglected tropical disease caused by various leishmanial parasites that primarily affect the world's poorest people. A limited number of standard medications are available for this disease that has been used for several decades, which have drawbacks such as resistance, higher cost, and patient compliance, making it difficult to reach the poor. The search for novel chemical entities to treat leishmaniasis has led to target-based scaffold research. Thiochromone moieties in conjugation with aromatic amino acids have been considered for the study, along with possible substitutions of the electron-withdrawing and electron-donating groups. N-myristoyl transferase (NMT) has been selected as the molecular target for the study responsible for protein-protein interaction and ribosylation of proteins necessary for the growth inside the human body of the parasite. The designed novel thiochromone analogs were docked against the selected leishmanial NMT using the in-silico methods, physicochemical and toxicity properties were predicted, and Structure-Activity Relationship was also established in-silico. Finally, a molecular dynamics simulation study for 100 ns gave an idea about the stability of the protein-ligand complex. A time frame analysis of each 10 ns confirmation was also studied to understand better the putative binding pattern designed analogs.
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    Advances in the synthesis of diarylpyrimidine as potent non-nucleoside reverse transcriptase inhibitors: biological activities, molecular docking studies and structure-activity relationship: a critical review
    (Bentham Science, 2023-04) Murugesan, Sankaranarayanan
    Acquired immunodeficiency syndrome (AIDS) is an ailment that is caused primarily by the Human immunodeficiency virus (HIV), which is the main agent responsible for this deadly disease. Of all the different inhibitors employed to curtail the menace caused by this deadly virus, non-nucleoside reverse transcriptase inhibitors (NNRTIs) have been cutting edge in the fight against AIDS. Over the past few years, the diaryl pyrimidine family and its derivatives have shown promising NNRTI properties attributed to their characteristic flexibility, targeting of conserved residues of reverse transcriptase, positional adaptability and, importantly, the formation of hydrogen bonds, which altogether led to the generation of secondgeneration NNRTIs. This breakthrough in the DAPY derivatives led to the development of TMC278 (rilpivirine) and TMC125 (etravirine), the two most recently approved NNRTIs by the FDA because of their low cytotoxicity, superior activities against mutant strains and WT HIV-1, excellent potency and high specificity. However, new challenges loom on the DAPY derivatives: the disappointing pharmacokinetic properties and accelerated emergence of resistance (particularly, K1013N and Y181C mutations, which are the two most important HIV-1 mutations that persist in most of the FDA-approved regimens), which implores further research to develop novel HIV-1 NNRTIs. In this review, we detail the reported different synthetic pathways for diaryl pyrimidine modification from published articles from 2010 to 2022, their biological activities, in addition to molecular docking studies and structure-activity relationships to uncover the possible molecular contributions that improved or reduced the NNRTIs properties. In a nutshell, the research findings provide valuable insights into the various modifications of the DAPY derivatives to develop novel NNRTIs.
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    Design, synthesis and biological evaluation of novel oxindole analogs as antitubercular agents
    (Taylor & Francis, 2023-08) Murugesan, Sankaranarayanan
    We synthesized the derivatives, confirmed their structures by 1H/13C NMR and mass spectrometry, and evaluated them for antitubercular activity against Mycobacterium tuberculosis H37Rv strain using the microplate alamarBlue™ assay. Results: Among all the synthesized derivatives, OXN-1, -3 and -7 exhibited excellent antitubercular activity (minimum inhibitory concentration [MIC]: 0.78 μg/ml). Compounds with a MIC ≤1.56 were tested for cytotoxicity against human embryonic kidney cells and were found to be relatively nontoxic. Molecular docking analysis of OXN-1, -3 and -7 was performed to determine their binding patterns at the active site of DNA topoisomerase II (PDB-5BS8). In drug combination studies, OXN-1, 3 and 7 showed synergism with isoniazid. Conclusion: The obtained results reveal that oxindole derivatives exhibit potent antitubercular activity.