Antitubercular Activity Research Articles

Synthesis, biological evaluation, and docking studies of pyrazole-linked benzothiazole hybrids as promising anti-TB agents

Tuberculosis (TB) is a global pandemic killing millions of people every year. Yet, resistant strains make curing TB quite challenging. Herein, a series of new pyrazole-linked benzothiazole hybrids was synthesized and evaluated for their anti-TB activity against three Mycobacterium tuberculosis strains (drug sensitive (DS), multidrug-resistant (MDR) and extensively drug-resistant (XDR)). The substituted 2,5-dimethylphenoxy -, 2,6-dichlorophenoxy -, 2,6-dimethoxyphenoxy -, 4-methylpiperazin-1-yl-,and pyrrolidin-1-ylpyrazole-benzothiazole conjugates (compounds 10j, 10k,10l, 11cand 12 respectively) displayed promising anti-TB activity in comparison to the reference compound isoniazid against the DS strain with (MIC: 1.74–3.68 μM/mL)To further study the mode of action of these anti-TB compounds, their inhibition of the Mycobacterium tuberculosisenoyl-acyl carrier protein reductase enzyme (InhA) was tested. The 3-acetamidophenoxy-, 2,6-dichlorophenoxy -,andpyrrolidin-1-ylpyrazole-benzothiazole conjugates(Compounds 10i, 10j and 12 respectively) showed strong inhibition of InhA in comparison to the reference compound, triclosan, with IC50 values of 6.4–7.9 μM. Moreover, a molecular docking study was carried out to investigate the predicted binding interactions of the synthesized inhA inhibitors in the binding pocket of the inhA enzyme. The calculated docking energies of the developed novel pyrazole-linked benzothiazole hybrids were consistent with their tested anti-tubercular activity.

Chemo-/regio-selective ultrasound-assisted synthesis of new spirooxindole-pyrrolidines/spirooxindole-pyrrolizines: Synthesis, antimicrobial and antitubercular activities, SAR and in silico studies

In an exploration of novel spirooxindole-pyrrolidine/spirooxindole-pyrrolizine-based compounds as antimicrobial and antitubercular agents, we have prepared a new series of pharmacologically privileged substructures, i.e., chalcone-isatin based spirooxindole compounds 12a-j, 13a-e, 14a-d, and 15–16 which were derived by the reaction of various substituted amino acids 11a-d, respectively, substituted chalcone (Me, OMe, Cl) 10a-m and isatins 9a-bvia one-pot three-component [3 + 2] cycloaddition reaction. We also report the SAR, and in silico molecular docking studies of 12a-j, 13a-e, 14a-d, and 15. While compared to the standard drug ampicillin (MIC = 25 µg/mL), compounds 13c, 13e, 14a, and 15 (MIC = 12.5 µg/mL) have shown to be twice as potent against the Bacillus subtilis [BS] bacterial strain. Compounds 12a and 13c (MIC = 25 µg/mL) exhibited equipotent behavior towards ampicillin (MIC = 25 µg/mL), a bacterial strain of B. subtilis [BS]. Compounds 13b (MIC = 3.125 µg/Ml) and 15 (MIC = 1.56 µg/mL) demonstrated strong antitubercular activity in the antitubercular activity assay when compared to the conventional medications Rifampicin (MIC = 0.2 µg/mL) and INH (MIC = 0.1 µg/mL). We also report, for the first time, in vitro antimicrobial activity of some previously reported spiro compounds 12c, 12f and 12 g.

Dual Antitubercular and Antileishmanial Profiles of Quinoxaline Di-N-Oxides Containing an Amino Acidic Side Chain.

We present a new category of quinoxaline di-N-oxides (QdNOs) containing amino acid side chains with dual antituberculosis and antileishmanial activity. These compounds were synthesized by combining a regioselective 2,5-piperazinedione opening and a Beirut reaction and were screened for their activity against Mycobacterium tuberculosis and the promastigote and amastigote forms of representative species of the Leishmania genus. Most QdNOs exhibited promising antitubercular activity with IC50 values ranging from 4.28 to 49.95 μM, comparable to clinically established drugs. Structure-activity relationship analysis emphasized the importance of substituents on the aromatic ring and the side chain. Antileishmanial tests showed that some selected compounds exhibited activity comparable to the positive control miltefosine against promastigotes of Leishmania amazonensis and Leishmania donovani. Notably, some compounds were found to be also more potent and less toxic than miltefosine in intracellular amastigote assays against Leishmania amazonensis. The compound showing the best dual antitubercular and leishmanicidal profile and a good selectivity index, 4h, can be regarded as a hit compound that opens up new opportunities for the development of integrated therapies against co-infections.

Microwave accelerated green access to functionalized pyrazolo[5,1-b]quinazoline-3-carboxylate scaffold and their pharmacological screening

Herein, we explored an environmentally benign synthesis of pyrazolo[5,1-b]quinazoline-3-carboxylate derivatives 4(a-u) as potential antimicrobial, antitubercular as well as antimalarial agents. Our approach employed microwave-assisted PEG-400 as a biodegradable reaction medium to expedite the one-pot fusion of 1,3-dicarbonyl compounds 1(a-c), substituted aldehydes 2(a-g), and ethyl-3-aminopyrazole-4-carboxylate (3a). The current protocol offers the advantages of a low E-factor, high atom economy, mild reaction condition, reusability of PEG-400 and produce water as a byproduct with a favorable yield (up to 96 % yield) in a short reaction time. Compared to the MIC values of standard antibiotics against their respective strains, compound 4g exhibited superior activity against Bacillus subtilis while compound 4r demonstrated a more favorable MIC against Pseudomonas aeruginosa. Against Candida albicans, compounds 4c, 4f, 4i, 4o, 4r, and 4u showed excellent antifungal activity as compared standard medications griseofulvin and fluconazole. Compounds 4d and 4p showed significant antitubercular activity against Mycobacterium tuberculosis H37Rv whereas compounds 4d, 4e, 4p and 4q showed good antimalarial activity against Plasmodium falciparum in contrast to standard drug ciprofloxacin and quinine respectively. In vitro cytotoxicity assay against S. pombe cells indicated that the majority of tested compounds exhibit more than 80 % cell viability, suggesting their non-toxic nature. A molecular docking study was conducted to elucidate the potential interactions between compound 4u and the active site of DNA gyrase. Based on the noteworthy findings from the investigation of drug-like properties and ADMET predictions, these derivatives depict an efficient multifunctional action and offer prospective access for future discoveries of antimicrobial, antitubercular, as well as antimalarial studies.

Synthesis and In vitro Screening of Pyrazine-2-Carbohydrazide Derivatives as Potential Antimicrobial Agents

Herein, we report the design of a new set of pyrazine-2-carbohydrazide derivatives (T1–T20) and in silico investigations to evaluate their inhibition activity against the enzyme, decaprenylphosphoryl-[Formula: see text]-D-ribose 2′-epimerase (DprE1). The derivatives interact with the Cys387 residue of the enzyme’s active site through hydrogen bonds. Further, we synthesized these compounds and evaluated their efficacy against the M. tuberculosis H37Rv strain. Compounds T16 and T19 displayed promising antitubercular activity, boasting a minimal inhibitory concentration of 1.56 [Formula: see text]g/mL. Furthermore, we assessed the antibacterial activity of these compounds against a range of pathogens, including S. aureus, S. mutans, E. coli and [Formula: see text]Typhi. Additionally, we evaluated their antifungal potency against A. niger. Notably, compounds T4, T8, T9, T16 and T19 exhibited noteworthy antibacterial activity against tested bacterial strains. Compounds T4, T9, T16, T17, T18 and T19 showed significant inhibition activity against A. niger. Importantly, all active compounds demonstrated low cytotoxicity, with IC50 values exceeding 300 [Formula: see text]M, ensuring no harm to normal cells. To gain a deeper understanding of these compounds, we conducted in silico investigations to evaluate their pharmacokinetics and pharmacochemical properties. Additionally, we employed DFT studies to explore the electronic characteristics of these compounds, providing valuable insights into their potential applications in the pharmaceutical field.

Antimicrobial properties of unusual eremophilanes from the endophytic Diaporthe sp. BCC69512

Six undescribed infrequent eremophilane derivatives including diaportheremopholins A – F and its previously undescribed side chain (E)-2-methyloct-2-enoic acid, together with three known compounds (testacein, xestodecalactones B and C), were isolated from the endophytic fungus Diaporthe sp. BCC69512. The chemical structures were determined based on NMR spectroscopic information in conjunction with the evidence from NOESY spectrum, Mosher's application, and chemical reactions for corroborating the absolute configurations. The isolated compounds were evaluated for biological properties such as antimalarial, anti-TB, anti-phytopathogenic fungal, antibacterial activities and for cytotoxicity against malignant (MCF-7 and NCI–H187) and non-malignant (Vero) cells. Diaportheremopholins B (2) and E (5) possessed broad antimicrobial activity against Mycobacterium tuberculosis, Bacillus cereus, Alternaria brassicicola and Colletotrichum acutatum with MICs in a range of 25.0–50.0 μg/mL. Testacein (7) exhibited strong anti-A. brassicicola and anti-C. acutatum activities with equal MIC values of 3.13 μg/mL. Moreover, diaportheremopholin F (6) and compound 8 displayed antitubercular activity with equal MIC values of 50.0 μg/mL. All tested compounds were non-cytotoxic against MCF-7, NCI–H187, and Vero cells, except those compounds 2 and 5–7 exhibited weak cytotoxicity against both malignant and non-malignant cells with IC50 values in a range of 15.5–115.5 μM.

Design, synthesis and characterization of ethyl 3-benzoyl-7-morpholinoindolizine-1-carboxylate as anti-tubercular agents: In silico screening for possible target identification.

A thorough search for the development of innovative drugs to treat tuberculosis, especially considering the urgent need to address developing drug resistance, we report here a synthetic series of ethyl 3-benzoyl-7-morpholinoindolizine-1-carboxylate analogues (5a-o) as potent anti-tubercular agents. These morpholino-indolizines were synthesized by reacting 4-morpholino pyridinium salts, with various electron-deficient acetylenes to afford the ethyl 3-benzoyl-7-morpholinoindolizine-1-carboxylate analogues (5a-o). All synthesized intermediate and final compounds are characterized by spectroscopic methods such as 1H NMR, 13C NMR and HRMS and further examined for their anti-tubercular activity against the M. tuberculosis H37Rv strain (ATCC 27294-American type cell culture). All the compounds screened for anti-tubercular activity in the range of 6.25-50 μM against the H37Rv strain of Mycobacterium tuberculosis. Compound 5g showed prominent activity with MIC99 2.55 μg/mL whereas compounds 5d and 5j showed activity with MIC99 18.91 μg/mL and 25.07 μg/mL, respectively. In silico analysis of these compounds revealed drug-likeness. Additionally, the molecular target identification for Malate synthase (PDB 5CBB) is attained by computational approach. The compound 5g with a MIC99 value of 2.55 μg/mL against M. tuberculosis H37Rv emerged as the most promising anti-TB drug and in silico investigations suggest Malate synthase (5CBB) might be the compound's possible target.

A Review on Diverse Biological Activity of Heterocyclic Nucleus Pyrazine and its Derivatives: A Key for the Researchers

Abstract: Pyrazine belongs to the 1, 4-diazines family, which is a significant class of heterocyclic compounds. Various pyrazine derivatives have been produced and successfully confirmed as medicines with various pharmacological activities like anti-inflammatory, antitubercular, anticancer, antibacterial, and neurological activity, with some of them becoming clinically utilized pharmaceuticals globally. This review includes a survey on pyrazine derivatives possessing different pharmacological activities. The class of pyrazine-based potential medications has grown rapidly in terms of both the absolute quantity of studied compounds and the range of various biological activities. Additionally, there is a lot of potential for this scaffold, which medicinal chemists ought to investigate for the creation of novel potential drug candidates.

Design, Synthesis, Characterization and Antitubercular Activity of Novel Benzimidazole Mannich Base Derivatives

In present work, the newly synthesized benzimidazole Mannich base derivatives were design, synthesized and evaluated the in silico and in vitro antitubercular activity. These compounds were synthesized by condensation reaction between 1-(1H-benzo[d]imidazol-1-yl)ethanone and aliphatic/aromatic amines. The synthesized compound structures were identified by FTIR, 13C NMR, 1H NMR and mass spectroscopies. The results indicated that these derivatives have significant antitubercular activity against Mycobacterium tuberculosis (M.tb) cell wall enzyme enoyl acyl carrier protein reductase (InhA), EthR regulatory protein in H73Rv strain. The results found in the in vitro study are firmly similar to the in silico study. Among the synthesized compounds, 3d and 3e exhibited the highest activity due to the connection of the electron-donating group to the Mannich base. Therefore, these compounds deserve the development of new antitubercular agents.

Synthesis, Molecular Docking, Molecular Dynamic Simulation Studies, and Antitubercular Activity Evaluation of Substituted Benzimidazole Derivatives.

Tuberculosis, also known as TB, is a widespread bacterial infection that remains a significant global health issue. This study focuses on conducting a thorough investigation into the synthesis, evaluation of anti-Tb activity, molecular docking, and molecular dynamic simulation of substituted benzimidazole derivatives. A series of twelve substituted benzimidazole derivatives (1-12) were successfully synthesized, employing a scaffold consisting of electron-withdrawing and electron-donating groups. The newly synthesized compounds were defined by their FTIR, 1H NMR, and mass spectra. The microplate Alamar blue assay (MABA) was used to evaluate the antimycobacterial activity of the synthesized compound against Mycobacterium tuberculosis (Mtb). Compounds 7 (MIC = 0.8 g/mL) and 8 (MIC = 0.8 g/mL) demonstrated exceptional potential to inhibit M. tuberculosis compared to the standard drug (isoniazid). In addition, the synthesized compounds were docked with the Mtb KasA protein (PDB ID: 6P9K), and the results of molecular docking and molecular dynamic simulation confirmed the experimental results, as compounds 7 and 8 exhibited the highest binding energy of -7.36 and -7.17 kcal/mol, respectively. The simulation results such as the RMSD value, RMSF value, radius of gyration, and hydrogen bond analysis illustrated the optimum potential of compounds 7 and 8 to inhibit the M. tuberculosis strain. Hydrogen bond analysis suggested that compound 7 has greater stability and affinity towards the KasA protein compared to compound 8. Moreover, both compounds (7 and 8) were safe for acute inhalation and cutaneous sensitization. These two compounds have the potential to be potent M. tuberculosis inhibitors.

Synthesis and In Vitro Antibacterial Evaluation of Mannich Base Nitrothiazole Derivatives

Nitrothiazole derivatives have been reported to exhibit activity against aerobic, anaerobic, and microaerophilic bacteria. This activity profile makes the nitrothiazole compound class an ideal lead source against Mycobacterium tuberculosis, which flourishes in varied environments with different oxygen concentrations. In this work, we investigated six nitrothiazole derivatives for antitubercular activity. The compounds exhibited potent activity, with compounds 9 and 10 possessing an equipotent MIC90 value of 0.24 µM. The compounds were investigated for cytotoxicity against HEK293 cells and hemolysis against red blood cells, and they demonstrated no cytotoxicity nor hemolytic effects, suggesting they possess inherent antitubercular activity.

Synthesis, biological evaluation and molecular docking study of pyrimidine linked thiazolidinedione derivatives as potential antimicrobial and antitubercular agents

The design and development of novel antimicrobial agents are highly desired to combat the emergence of medication resistance against microorganisms that cause infections. A series of new pyrimidine-linked thiazolidinedione derivatives (5a-j) were synthesized, characterized, and their antimicrobial properties assessed in the current investigation. Here, novel pyrimidine-linked thiazolidinedione compounds were designed using the molecular hybridization approach. Elemental and spectral techniques were used to determine the structures of the synthesized hybrids. The majority of compounds showed encouraging antibacterial properties. Among the active compounds, 5g, 5i, and 5j showed 1.85, 1.15, and 1.38 times the activity of streptomycin against S. aureus, respectively, with MIC values of 6.4, 10.3, and 8.6 µM. With MIC values of 10.8, 21.9, and 15.4 µM, respectively, the compounds 5g, 5i, and 5j showed 2.14, 1.05, and 1.50 times the activity of linezolid against the methicillin-resistant S. aureus (MRSA) strain. Furthermore, when compared to the reference medications, compounds 5g, 5i, and 5j demonstrated broad-range antimicrobial efficacy against all tested strains of bacteria and fungus. Out of all the compounds that were investigated, compounds 5g, 5i, and 5j showed noteworthy anti-tubercular activity. 5g is the most effective, 1.59 times more effective than reference drug isoniazid. To anticipate the binding manner, the synthesized potent compounds were subjected to molecular docking into the active binding site of MRSA and the mycobacterial membrane protein large 3 (MmpL3) protein. The compounds 5g, 5i, and 5j may eventually serve as lead compounds in the search for antimicrobial and anti-TB therapeutic agents.

Structure-based drug design and characterization of novel pyrazine hydrazinylidene derivatives with a benzenesulfonate scaffold as noncovalent inhibitors of DprE1 tor tuberculosis treatment.

In this study, we present a novel series of (E)-4-((2-(pyrazine-2-carbonyl) hydrazineylidene)methyl)phenyl benzenesulfonate (T1-T8) and 4-((E)-(((Z)-amino(pyrazin-2-yl)methylene)hydrazineylidene)methyl)phenyl benzenesulfonate (T9-T16) derivatives which exert their inhibitory effects on decaprenylphosphoryl-β-D-ribose 2'-epimerase (DprE1) through the formation of hydrogen bonds with the pivotal active site Cys387 residue. Their effectiveness against the M. tuberculosis H37Rv strain was examined and notably, three compounds (namely T4, T7, and T12) exhibited promising antitubercular activity, with a minimum inhibitory concentration (MIC) of 1.56µg/mL. The target compounds were screened for their antibacterial activity against a range of bacterial strains, encompassing S. aureus, B. subtilis, S. mutans, E. coli, S. typhi, and K. pneumoniae. Additionally, their antifungal efficacy against A. fumigatus and A. niger also was scrutinized. Compounds T6 and T12 demonstrated significant antibacterial activity, while compound T6 exhibited substantial antifungal activity. Importantly, all of these active compounds demonstrated exceedingly low toxicity without any adverse effects on normal cells. To deepen our understanding of these compounds, we have undertaken an in silico analysis encompassing Absorption, Distribution, Metabolism, and Excretion (ADME) considerations. Furthermore, molecular docking analyses against the DprE1 enzyme was conducted and Density-Functional Theory (DFT) studies were employed to elucidate the electronic properties of the compounds, thereby enhancing our understanding of their pharmacological potential.

Synthesis, Docking Studies, and Biological Evaluation of Some New Pyrrolyl Benzohydrazide Derivatives

A series of 16 new N-(2-(4-(1H-pyrrol-1-yl)phenoxy)acetyl)-N-substituted benzohydrazides was synthesized by the reaction of 1-(1H-pyrrol-1-yl)benzohydrazide with substituted benzoic acids in the presence of N,N-dimethylformamide, HBTU, and DIEA. Molecular docking and biological screening were done on the synthesized compounds to conduct antitubercular and antibacterial activity tests. The selected compounds were investigated for the inhibition of the InhA and DHFR enzymes. Promising antitubercular, antibacterial, and enzyme inhibitory action has been shown for all molecules. Absorption, distribution, metabolism, elimination, and toxicity investigations were also completed.. KEYWORDS :Antitubercular, Benzohydrazides, Docking, In silico, Pyrrole.

Oxacyanopyridine-Benzofuran Hybrids: Synthesis, in silico Toxicity Assessment, in vitro Antimicrobial Activity and Dual Target Docking Studies

This study emphasizes the synthesis and characterization of a novel series of oxa cyano pyridine heterocyclic molecular hybrids (OCP 1-6), integrating pyridine and benzofuran motifs. Meticulously designed from 5-chlorosalicylaldehyde in a multistep process, the synthesized compounds were structurally confirmed through IR spectroscopy, 1H NMR spectroscopy, and mass spectrometry. Computational predictions highlighted diverse properties, including antitubercular and antibacterial attributes, bioactivity scores, toxicity profiles and potential molecular targets. In vitro assessments and Schrödinger docking simulations revealed binding affinities to enzymes viz. Mycobacterium tuberculosis enoyl-ACP reductase and Escherichia coli Topoisomerase IV. Compounds, particularly OCP 2, 3, 4 and 5, exhibited significant antitubercular and antibacterial activities in both in vitro assessments and docking simulations. This study underscores the substantial potential of the synthesized hybrids as promising candidates for further lead optimization, positioning them as valuable contributors to the development of pharmaceutical agents with heightened potency and enhanced safety profiles.

Thiazolotriazoles As Anti-infectives: Design, Synthesis, Biological Evaluation and In Silico Studies.

The rational design of novel thiazolo[2,3-c][1,2,4]triazole derivatives was carried out based on previously identified antitubercular hit molecule H127 for discovering potent compounds showing antimicrobial activity. The designed compounds were screened for their binding efficacies against the antibacterial drug target enoyl-[acyl-carrier-protein] reductase, followed by prediction of drug-likeness and ADME properties. The designed analogues were chemically synthesized, characterized by spectroscopic techniques, followed by evaluation of antimicrobial activity against bacterial and fungal strains, as well as antitubercular activity against M. tuberculosis and M. bovis strains. Among the synthesized compounds, five compounds, 10, 11, 35, 37 and 38, revealed antimicrobial activity, albeit with differential potency against various microbial strains. Compounds 10 and 37 were the most active against S. mutans (MIC: 8 μg/mL), while compounds 11 and 37 showed the highest activity against B. subtillis (MIC: 16 μg/mL), whereas compounds 10, 11 and 37 displayed activities against E. coli (MIC: 16 μg/mL). Meanwhile, compounds 10 and 35 depicted activities against S. typhi (MIC: 16 μg/mL) and compound 10 showed antifungal activity against C. albicans (MIC: 32 μg/mL). The current study has identified two broad-spectrum antibacterial hit compounds (10 and 37). Further structural investigation on these molecules is underway to enhance their potency.

In silico design, synthesis and antitubercular activity of novel 2-acylhydrazono-5-arylmethylene-4-thiazolidinones as enoyl-acyl carrier protein reductase inhibitors

Mycobacteria regulate the synthesis of mycolic acid through the fatty acid synthase system type 1 (FAS I) and the fatty acid synthase system type-2 (FAS-II). Because mammalian cells exclusively utilize the FAS-I enzyme system for fatty acid production, targeting the FAS-II enzyme system could serve as a specific approach for developing selective antimycobacterial drugs. Enoyl-acyl carrier protein reductase enzyme (MtInhA), part of the FAS-II enzyme system, contains the NADH cofactor in its active site and reduces the intermediate. Molecular docking studies were performed on an in-house database (∼2200 compounds). For this study, five different crystal structures of MtInhA (PDB Code: 4TZK, 4BQP, 4D0S, 4BGE, 4BII) were used due to rotamer difference, mutation and the presence of cofactors. Molecular dynamics simulations (250 ns) were performed for the novel 2-acylhydrazono-5-arylmethylene-4-thiazolidinones derivatives selected by molecular docking studies. Twenty-three compounds selected by in silico methods were synthesized. Antitubercular activity and MtInhA enzyme inhibition studies were performed for compounds whose structures were elucidated by IR,1H-NMR,13C-NMR, HSQC, HMBC, MS and elemental analysis. Communicated by Ramaswamy H. Sarma

Unveiling the Antimicrobial and Larvicidal Potential of Butyrolactones and Orsellinic Acid Derivatives from the Morus alba-derived Fungus Aspergillus terreus via Integrated In vitro and In silico Approaches.

The emergence of multi-drug-resistant microbial strains spurred the search for antimicrobial agents; as a result, two distinct approaches were combined: four in vitro studies and four corresponding molecular docking investigations. Antituberculosis, anti-methicillin-resistant Staphylococcus aureus (anti-MRSA), antifungal, and larvicidal activities of the crude extract, two fractions, and seven isolated compounds from Aspergillus terreus derived from Morus alba roots were explored. The isolated compounds (5 butyrolactones and 2 orsellinic acid derivatives) showed potent to moderate antitubercular activity with MIC values ranging from 1.95 to 62.5 μg/mL (compared to isoniazid, 0.24 μg/mL) and promising anti-MRSA potential with inhibition zone diameters ranging from 8 to 25 mm. Additionally, the in silico study proved that the isolated compounds bind to the two corresponding proteins' active sites with high to moderate -(C-Docker interaction energies) and stable interactions. The isolated compounds displayed antifungal activities against different fungal strains at diverse degrees of activity, among them compound (8"S,9")-dihydroxy-dihydrobutyrolactone I eliciting the best antifungal activity. Meanwhile, all isolated compounds, fractions, and the crude extract demonstrated extremely selective potent to moderate activity against Cryptococcus neoformans. The isolated five butyrolactone derivatives could develop potential mosquito larvicidal agents as a result of promising docking outcomes in the larval enzyme carboxylesterase.

The Antitubercular Activities of Natural Products with Fused-Nitrogen-Containing Heterocycles.

Tuberculosis (TB) is notorious as the leading cause of death worldwide due to a single infectious entity and its causative agent, Mycobacterium tuberculosis (Mtb), has been able to evolve resistance to all existing drugs in the treatment arsenal complicating disease management programs. In drug discovery efforts, natural products are important starting points in generating novel scaffolds that have evolved to specifically bind to vulnerable targets not only in pathogens such as Mtb, but also in mammalian targets associated with human diseases. Structural diversity is one of the most attractive features of natural products. This review provides a summary of fused-nitrogen-containing heterocycles found in the natural products reported in the literature that are known to have antitubercular activities. The structurally targeted natural products discussed in this review could provide a revealing insight into novel chemical aspects with novel biological functions for TB drug discovery efforts.

Synthesis and Antitubercular Evaluation of Diverse Glycosylated Ureas from D-Glucose

N, N-disubstituted glycosylated ureas have been synthesized in good-to-excellent yields by 1,4-conjugate addition of amines to glycosylated olefinic esters followed by reaction of resulting glycosyl β-amino esters with diisocyanates. The developed sugar-based molecules were well characterized by extensive standard spectroscopic analysis including NMR (1H, 13C, and DEPT), IR, MS, and elemental analysis and were screened for their biological activity against Mycobacterium tuberculosis (M. Tb.), where some of them displayed potent antitubercular activity. The molecules have been designed keeping in view the well-known inhibitors of the enzymes involved in the biosynthesis of mycobacterial cell wall polymers and may be further explored as lead molecules for the successful development of a potential antitubercular drug candidate.Dedicated to Dr. Rama P. Tripathi, Former Chief Scientist at CSIR-Central Drug Research Institute, Lucknow, India, for his extraordinary contribution to “Drug development against Tuberculosis”