Design, synthesis, and anti-mycobacterial evaluation of 1,8-naphthyridine-3-carbonitrile analogues.

Twenty-eight compounds, viz., 1,8-naphthyridine-3-carbonitrile (ANC and ANA) derivatives, were designed and synthesized through a molecular hybridization approach. The structures of these compounds were analyzed and confirmed using 1H NMR, 13C NMR, LCMS, and elemental analyses. The synthesized compounds were evaluated by in vitro testing for their effectiveness against tuberculosis using the MABA assay, targeting the Mycobacterium tuberculosis H37Rv strain. Their minimum inhibitory concentration (MIC) was determined, showing that the tested compounds' MIC values ranged from 6.25 to ≤50 µg mL-1. Among the derivatives studied, ANA-12 demonstrated prominent anti-tuberculosis activity with a MIC of 6.25 µg mL-1. Compounds ANC-2, ANA-1, ANA 6-8, and ANA-10 displayed moderate to good anti-tuberculosis activity with MIC values of 12.5 µg mL-1. Compounds with MIC ≤ 12.5 µg mL-1 were screened against human embryonic kidney cells to assess their potential cytotoxicity. Interestingly, these compounds showed less toxicity towards normal cells, with a selectivity index value ≥ 11. To further evaluate the binding pattern in the active site of enoyl-ACP reductase (InhA) from Mtb (PDB-4TZK), a molecular docking analysis of compound ANA-12 was performed using the glide module of Schrodinger software. The stability, confirmation, and intermolecular interactions of the cocrystal ligand and the highly active compound ANA-12 on the chosen target protein were investigated through molecular dynamics simulations lasting 100 ns. In silico predictions were utilized to assess the ADMET properties of the final compounds. A suitable single crystal was developed and analyzed for compound ANA-5 to gain a deeper understanding of the compounds' structures.

Identification of N-Benzylated Indole Mannich Bases as Potential Anti TB Agents by Using Computational Studies and Molecular Hybridization Technique.

INTRODUCTION: Morbidity and mortality due to tuberculosis are rising steadily. Despite having efficient drugs and treatment protocols, microbial drug resistance often leads to treatment failure. Efforts to bring novel drugs to combat this menace are hampered by several issues including problems in gaining industry support, motivation and ethical issues clinical trials. Bedaquiline and Delaminid are the only novel drugs approved in the last three decades for treating TB. A few more molecules and drug combinations are still in clinical trials. One such drug is the BM212, a potent anti-TB agent which acts by a novel mechanism of action. METHODS: In the present study, we used virtual screening method with a combination of molecular hybridization technique to design N-benzylated Indole Mannich bases as potent anti-TB agent based on BM212 pharmacophore. The library of designed molecules was prepared and screened using BM212 model. The top 5 'hit' molecules were selected (with good TC score >1.15), synthesized and screened for anti TB activity by MABA assay method. RESULTS AND CONCLUSION: All the compounds showed excellent anti TB activity, of which 4 compounds have shown MIC ≤12.5 µg/mL. Our protocol could help in the designing of newer anti-TB agents with better bioactivity profile.

Seeking potent anti-tubercular agents: Design, synthesis, anti-tubercular activity and docking study of various ((triazoles/indole)-piperazin-1-yl/1,4-diazepan-1-yl)benzo[d]isoxazole derivatives.

A series of thirty eight novel 3-(4-((substituted-1H-1,2,3-triazol-4-yl)methyl)piperazin-1-yl/1,4-diazepan-1-yl)benzo[d]isoxazole and 1-(4-(benzo[d]isoxazol-3-yl)piperazin-1-yl/1,4-diazepan-1-yl)-2-(1H-indol-3-yl)substituted-1-one analogues were synthesised, characterised using various analytical techniques and evaluated for in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain and two 'wild' strains Spec. 210 and Spec. 192. The titled compounds exhibited minimum inhibitory concentration (MIC) ranging from 6.16 to >200µM. Among the tested compounds, 7i, 7y and 7z exhibited moderate activity (MIC=24.03-29.19µM) and 7j exhibited very good anti-tubercular activity (MIC=6.16µM). Furthermore, 7i, 7j, 7y and 7z were found to be non-toxic against mouse macrophage cell lines when screened for toxicity. All the synthesised compounds were docked to pantothenate synthetase enzyme site to know deferent binding interactions with the receptor.

3D QSAR analysis of 2-(substituted aryl)-thiazolidine-4-carboxamides as potent antitubercular agents.

Thiazolidine-4-carboxylic acid derivatives were recognized recently for their potent antitubercular activity. A total of sixty four thiazolidine derivatives published in the recent times were collected and 3D QSAR models were developed, using CoMFA and COMSIA with high predictability. Later, we selected three new molecules, recently synthesized in our lab and evaluated them using the developed QSAR models. The in vitro antitubercular activity (MIC) obtained for these new molecules is in agreement with the predicted values (pMIC).

Rubrolide R: a new furanone metabolite from the ascidian Synoicum of the Indian Ocean.

A new furanone metabolite of the rubrolide family, rubrolide R as diacetate (1), was isolated from a new species of the ascidian Synoicum, besides the known compounds rubrolide A (as diacetate), cadiolide B and prunolide A. The structure of the new rubrolide was elucidated by a study of spectral data. The crude extract and isolated compounds (prunolide A and cadiolide B) showed antiviral activity against the Japanese encephalitis virus. Prunolide A showed cytotoxic activity against breast cancer cell lines at a concentration of < 1 µM.

AUDocker LE: A GUI for virtual screening with AUTODOCK Vina.

BACKGROUND: AUTODOCK Vina is an open-source program which is steadfast and authentic to perform docking simulations. Though, Auto Dock Tools can help perform docking simulations with Vina, it largely remains as a platform for docking single molecule at a time. FINDINGS: "AUDocker LE" is designed with an aim to develop a software tool as a front end graphical interface with C# language to perform docking experiments in Windows based computers. It helps users to perform automated continuous docking of large ligand databases into a set of predefined protein targets. It will also help the user to analyze the results to select promising lead molecules. CONCLUSION: AUDocker LE provides a straight forward graphical interface which can be used in a standard personal computer with Microsoft Windows XP or Windows 7 as the operating system where Autodock Vina, Python 2.5 and .net frame work are preinstalled.