Mycobacterium Tuberculosis H37Rv Research Articles

A hit expansion of 3-benzamidopyrazine-2-carboxamide: Towardinhibitors of prolyl-tRNA synthetase with antimycobacterial activity.

This study presents an exploration of the chemical space around derivatives of 3-benzamidopyrazine-2-carboxamides, previously identified as potent antimycobacterial compounds with predicted binding to mycobacterial prolyl-transfer RNA synthetase. New urea derivatives (Series-1) were generally inactive, probably due to their preference for cis-trans conformation (confirmed by density functional theory calculations and experimentally by nuclear overhauser effect spectroscopy NMR). Series-2 (3-benzamidopyrazine-2-carboxamides with disubstituted benzene ring) demonstrated that substituents larger than fluorine are not tolerated in the ortho position of the benzene ring. This series brought two new compounds (21: R = 2-F, 4-Cl and 22: R = 2-F, 4-Br) with in vitro activity against Mycobacterium tuberculosis H37Rv as well as multidrug-resistant clinical isolates, with minimum inhibitory concentration ranging from 6.25 to 25 μg/mL. The lactone-type derivatives 4H-pyrazino[2,3-d][1,3]oxazin-4-ones (Series-3) were inactive, but solvent stability studies of compound 29 indicated that they might be developed to usable lactone prodrugs of inhibitors of mycobacterial aspartate decarboxylase (PanD).

UHPLC-HRMS/MS Chemical Fingerprinting of the Bioactive Partition from Cultivated Piper aduncum L.

Piper aduncum L. is widely distributed in tropical regions and the ethnobotanical uses of this species encompass medicinal applications for the treatment of respiratory, antimicrobial, and gynecological diseases. Chemical studies reveal a diverse array of secondary metabolites, including terpenes, flavonoids, and prenylated compounds. Extracts from P. aduncum have shown antibacterial, antifungal, and larvicidal activities. Our study explores the activity of extracts and partitions against Mycobacterium tuberculosis H37Rv, as well as the chemical diversity of the bioactive partition. This marks the first investigation of the bioactive partition of P. aduncum from agroecological cultivation. The ethyl acetate partition from the ethanolic leaf extract (PAEPL) was found to be the most active. PAEPL was subjected to column chromatography using Sephadex LH-20 and the obtained fractions were analyzed using UHPLC-HRMS/MS. The MS/MS data from the fractions were submitted to the online GNPS platform for the generation of the molecular network, which displayed 1714 nodes and 167 clusters. Compounds were identified via manual inspection and different libraries, allowing the annotation of 83 compounds, including flavonoids, benzoic acid derivatives, glycosides, free fatty acids, and glycerol-esterified fatty acids. This study provides the first chemical fingerprint of an antimycobacterial sample from P. aduncum cultivated in an agroecological system.

BIOLOGICAL MODEL OF LUNG CANCER COMBINATION AND TUBERCULOSIS: DEVELOPMENT FOR PRECLINICAL STUDY OF RATIONAL COMBINATIONS OF TARGETED ANTITUMOR AND ANTITUBERCULOSIS THERAPY

Introduction. Lung cancer occupies a leading position in the structure of mortality from cancer. Chronic inflammation characteristic of tuberculosis increases the risk of lung cancer. Currently, more and more information is emerging confirming the cause-and-effect relationship between tuberculosis and cancer. The need to develop recommendations for public health regarding screening and treatment of tuberculosis in the tumor process determines the relevance of experimental studies on biological models of the combination of cancer and tuberculosis.. Aim. Creation а biological model of the combination of lung cancer and tuberculosis for preclinical study of rational combinations of antitumor and antituberculosis therapy. Material and methods: The biological model was implemented on C57BL/6 mice at the age of two months. Lewis epidermoid lung carcinoma was used to reproduce the tumor process. Modeling of tuberculosis was carried out using the reference strain Mycobacterium Tuberculosis H37RV. During the study, the following groups were formed: “intact mice” (healthy, uninfected with the Mycobacterium Tuberculosis (MBT) H37Rv strain without tumor cell transplantation); “control of MBT infection” (animals infected with Mycobacterium Tuberculosis strain H37Rv), “tumor control” (animals that were transplanted with epidermoid Lewis lung carcinoma) and “main group” (animals that were transplanted with epidermoid Lewis lung carcinoma simultaneously with MBT infection). Results. During the experiment, several models for creating the combined pathology of lung cancer and tuberculosis were identified. In the first (simultaneous infection and tumor inoculation), carcinoma developed more slowly in infected animals than in the tumor control group, and lung damage occurred with a predominance of the tuberculous process over the tumor process. The second (staged infection) also showed minimal metastatic manifestations with pronounced secondary changes in the primary tumor node. Analysis of the choice of model showed that the model with simultaneous infection and tumor inoculation most adequately ensures the development of the tumor process and tuberculosis infection, which allows maintaining the viability of the animal, fully developing the tumor process with metastasis to the lungs and obtaining the development of morphologically verified pulmonary tuberculosis.

Protocol for the selection of Mycobacterium tuberculosis spontaneous resistant mutants to d-cycloserine

Mycobacterium tuberculosis (MTB) is known for its adaptive capability in developing resistance to antibiotics, through the selection of spontaneous mutations that arise during treatment. Generating spontaneous antibiotic-resistant mutants in vitro is challenging but necessary for studying this phenomenon. A protocol was designed and tested to select stable, MTB spontaneous, d-cycloserine (DCS) resistant mutants. Twenty-four colonies resistant to DCS were selected, demonstrating an increase between 1 and 4 times the Minimum Inhibitory Concentration (MIC) set for Mycobacterium tuberculosis H37Rv ATCC 27294 reference strain.

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, compounds 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.

Anti-Tuberculosis Study of Mycobacterium tuberculosis H37Rv of Aspilia pluriceta Extract and Fractions

Anti-Tuberculosis Study of Mycobacterium tuberculosis H37Rv of Aspilia pluriceta Extract and Fractions

Molecular docking, molecular dynamics simulations and binding free energy studies of interactions between Mycobacterium tuberculosis Pks13, PknG and bioactive constituents of extremophilic bacteria

Mycobacterial pathogens present a significant challenge to disease control efforts globally due to their inherent resistance to multiple antibiotics. The rise of drug-resistant strains of Mycobacterium tuberculosis has prompted an urgent need for innovative therapeutic solutions. One promising way to discover new tuberculosis drugs is by utilizing natural products from the vast biochemical space. Multidisciplinary methods can used to harness the bioactivity of these natural products. This study aimed to evaluate the antimycobacterial efficacy of functional crude extracts from bacteria isolated from gold mine tailings in South Africa. Bacterial strains were identified using 16S rRNA sequencing. The crude extracts obtained from the bacteria were tested against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. Untargeted HPLC-qTOF and molecular networking were used to identify the functional constituents present in extracts that exhibited inhibitory activity. A virtual screening workflow (VSW) was used to filter compounds that were strong binders to Mycobacterium tuberculosis Pks13 and PknG. The ligands returned from the VSW were subjected to optimization using density functional theory (DFT) at M06-2X/6-311++ (d,p) level of theory and basis set implemented in Gaussian16 Rev.C01. The optimized ligands were re-docked against Mycobacterium tuberculosis Pks13 and PknG. Molecular dynamics simulation and molecular mechanics generalized born surface area were used to evaluate the stability of the protein–ligand complexes formed by the identified hits. The hit that showed promising binding characteristics was virtually modified through multiple synthetic routes using reaction-driven enumeration. Three bacterial isolates showed significant activity against the two strains of Mycobacterium, while only two, Bacillus subtilis and Bacillus licheniformis, exhibited activity against both Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. The tentatively identified compounds from the bacterial crude extracts belonged to various classes of natural compounds associated with antimicrobial activity. Two compounds, cyclo-(L-Pro-4-OH-L-Leu) and vazabitide A, showed strong binding against PknG and Pks13, with pre-MD MM-GBSA values of − 42.8 kcal/mol and − 47.6 kcal/mol, respectively. The DFT-optimized compounds exhibited the same docking scores as the ligands optimized using the OPSL-4 force field. After modifying vazabitide A, its affinity to the Pks13 binding site increased to − 85.8 kcal/mol, as revealed by the post-MD MM-GBSA analysis. This study highlights the potential of bacteria isolates from gold mine tailings as a source of new scaffolds for designing and optimizing anti-Mycobacterium agents. These agents synthesized in-silico can be further tested in-vitro to evaluate their efficacy.

Triple combination dry powder formulation of pretomanid, moxifloxacin, and pyrazinamide for treatment of multidrug-resistant tuberculosis

Both latent and multidrug-resistant tuberculosis (TB) have been causing significant concern worldwide. A novel drug, pretomanid (PA-824), has shown a potent bactericidal effect against both active and latent forms of Mycobacterium tuberculosis (MTb) and a synergistic effect when combined with pyrazinamide and moxifloxacin. This study aimed to develop triple combination spray dried inhalable formulations composed of antitubercular drugs, pretomanid, moxifloxacin, and pyrazinamide (1:2:8 w/w/w), alone (PaMP) and in combination with an aerosolization enhancer, L-leucine (20 % w/w, PaMPL). The formulation PaMPL consisted of hollow, spherical, dimpled particles (<5 μm) and showed good aerosolization behaviour with a fine particle fraction of 70 %. Solid-state characterization of formulations with and without L-leucine confirmed the amorphous nature of moxifloxacin and pretomanid and the crystalline nature of pyrazinamide with polymorphic transformation after the spray drying process. Further, the X-ray photoelectron spectroscopic analysis revealed the predominant surface composition of L-leucine on PaMPL dry powder particles. The dose–response cytotoxicity results showed pyrazinamide and moxifloxacin were non-toxic in both A549 and Calu-3 cell lines up to 150 µg/mL. However, the cell viability gradually decreased to 50 % when the pretomanid concentration increased to 150 µg/mL. The in vitro efficacy studies demonstrated that the triple combination formulation had more prominent antibacterial activity with a minimum inhibitory concentration (MIC) of 1 µg/mL against the MTb H37Rv strain as compared to individual drugs. In conclusion, the triple combination of pretomanid, moxifloxacin, and pyrazinamide as an inhalable dry powder formulation will potentially improve treatment efficacy with fewer systemic side effects in patients suffering from latent and multidrug-resistant TB.

Structural and biophysical characterization of PadR family protein Rv1176c of Mycobacterium tuberculosis H37Rv

Rv1176c of Mycobacterium tuberculosis H37Rv belongs to the PadR-s1 subfamily of the PadR family of protein. Rv1176c forms a stable dimer in solution. Its stability is characterized by a thermal melting transition temperature (Tm) of 39.4 °C. The crystal structure of Rv1176c was determined at a resolution of 2.94 Å, with two monomers in the asymmetric unit. Each monomer has a characteristic N-terminal winged-helix-turn-helix DNA-binding domain. Rv1176c C-terminal is a coiled-coil dimerization domain formed of α-helices α5 to α7. In the Rv1176c dimer, there is domain-swapping of the C-terminal domain in comparison to other PadR homologs. In the dimer, there is a long inter-subunit tunnel in which different ligands can bind. Rv1176c was found to bind to the promoter region of its own gene with high specificity. M. smegmatis MC2 155 genome lacks homolog of Rv1176c. Therefore, it was used as a surrogate to characterize the functional role of Rv1176c. Expression of Rv1176c in M. smegmatis MC2 155 cells imparted enhanced tolerance towards oxidative stress. Rv1176c expressing M. smegmatis MC2 155 cells exhibited enhanced intracellular survival in J774A.1 murine macrophage cells. Overall, our studies demonstrate Rv1176c to be a PadR-s1 subfamily transcription factor that can moderate the effect of oxidative stress.

Mesenchymal stem cells-derived extracellular vesicles for therapeutics of renal tuberculosis

Extrapulmonary tuberculosis with a renal involvement can be a manifestation of a disseminated infection that requires therapeutic intervention, particularly with a decrease in efficacy of conventional regimens. In the present study, we investigated the therapeutic potency of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in the complex anti-tuberculosis treatment (ATT). A rabbit model of renal tuberculosis (rTB) was constructed by injecting of the standard strain Mycobacterium tuberculosis H37Rv into the cortical layer of the kidney parenchyma. Isolated rabbit MSC-EVs were intravenously administered once as an addition to standard ATT (isoniazid, pyrazinamide, and ethambutol). The therapeutic efficacy was assessed by analyzing changes of blood biochemical biomarkers and levels of anti- and pro-inflammatory cytokines as well as by renal computed tomography with subsequent histological and morphometric examination. The therapeutic effect of therapy with MSC-EVs was shown by ELISA method that confirmed a statistically significant increase of the anti-inflammatory and decrease of pro-inflammatory cytokines as compared to conventional treatment. In addition, there is a positive trend in increase of ALP level, animal weigh, and normalization of ADA activity that can indicate an improvement of kidney state. A significant reduction of the area of specific and interstitial inflammation indicated positive affect of MSC-EVs that suggests a shorter duration of ATT. The number of MSC-EVs proteins (as identified by mass-spectometry analysis) with anti-microbial, anti-inflammatory and immunoregulatory functions reduced the level of the inflammatory response and the severity of kidney damage (further proved by morphometric analysis). In conclusion, MSC-EVs can be a promising tool for the complex treatment of various infectious diseases, in particularly rTB.

Two new naturally dimers constituent from Indonesian Sesbania grandiflora plant and their bioactivity

Abstract A new dimer of natural isoflavonoid along with some known flavonoid compounds was successfully isolated from the roots of Indonesian Sesbania grandiflora plant using ethyl acetate extraction. The new compound specified as naturally bi-isoflavonoid with (4→6) inter-isoflavanyl linkage and four known flavonoids xenognosin B, liquiritigenin, 7,2′4′-trihydroxyisoflavone, demethylvestitol, and 1,1′-bi-2-naphthol was isolated and the antituberculosis activity of the compounds was studied. The structure of all compounds was elucidated with the aid of 1D and 2D NMR, UV spectroscopy, and HRESI mass spectrometry. The data obtained were also compared with the previous published data. Among compounds, 1,1′-bi-2-naphthol was found to exhibit the highest activity against Mycobacterium tuberculosis H37Rv with the MIC’s value of 10.9 µM while the biisoflavonoid with (4→6) inter-isoflavanyl linkage showed moderate activity with the MIC’s value of 92.2 nM, compared with isozianid as a positive control with the MIC’s value of 0.569 nM. It is worth to note that 1,1′-bi-2-naphthol and biisoflavonoid with (4→6) inter-isoflavanyl linkage were isolated for the first time from a natural source. Both compounds have been previously reported as synthetic compounds, which is synonymous with 3,4- trans-4-[(3S)-7,2′-dihydroxy-4′-methoxyisoflavan-6-yl]-7,2′-dihydroxy-4′-methoxyisoflavan and 1,1′-bi-2-naphthol, respectively. In this respect, the results of this study suggest that the roots of S. grandiflora is a potential source of new natural product compounds, with promising bioactivities.

Comparative transcriptomics reveals common and strain-specific responses of human macrophages to infection with Mycobacterium tuberculosis and Mycobacterium bovis BCG

Mycobacterium tuberculosis (MTB) and Mycobacterium bovis (M. bovis) are closely related pathogenic mycobacteria known to cause chronic pulmonary infections in both humans and animals. Despite sharing nearly identical genomes and virulence factors, these two bacteria display variations in host tropism, epidemiology, and clinical presentations. M. bovis Bacillus Calmette–Guérin (BCG) is an attenuated strain of M. bovis commonly utilized as a vaccine for tuberculosis (TB). Nevertheless, the molecular underpinnings of these distinctions and the intricacies of host-pathogen interactions remain areas of ongoing research. In this study, a comparative transcriptomic analysis was conducted on human leukemia macrophages (THP-1) infected with either MTB H37Rv or M. bovis BCG (Tokyo strain) to elucidate common and strain-specific responses at the transcriptional level. RNA sequencing was utilized to characterize the transcriptomes of human primary macrophages infected with MTB or BCG at 6 and 24 h post-infection. The findings indicate that both MTB and BCG induce substantial and dynamic alterations in the transcriptomes of THP-1, with a notable overlap in the quantity and extent of differentially expressed genes (DEGs). Moreover, gene ontology (GO) enrichment analysis unveiled shared pathways related to immune response, cytokine signaling, and apoptosis. The immune response of macrophages to bacterial infections at 6 h exhibited significantly greater intensity compared to that at 24 h. Furthermore, distinct gene sets displaying notable variances between MTB and BCG infections were identified. The profound impact of MTB infection on macrophage gene expression, particularly within the initial 6 h, was evident. Additionally, downregulation of pathways such as Focal adhesion, Rap1 signaling pathway, and Regulation of actin cytoskeleton was observed. The pathways associated with inflammation reactions and cell apoptosis exhibited significant differences, with BCG triggering macrophage apoptosis and MTB enhancing the survival of intracellular bacteria. Our findings reveal that MTB and BCG provoke similar yet distinct transcriptional responses in human macrophages, indicating variations in their pathogenesis and ability to adapt to host environments. These results offer novel insights into the molecular mechanisms governing host-pathogen interactions and may contribute to a deeper understanding of TB pathogenesis.

Metal Catalyst-Free One-pot Synthesis of Carboxamide Derivatives via Ugi-4CC Reaction and Its Anti-tubercular Study

Background: A new series of ten composites with sulphur based carboxylic acid and benzylamine were synthesized by Ugi 4-components reaction (Ugi-4CR) and screened for antituberculosis activity against the Mycobacterium tuberculosis H37Rv strain. Objective: Target compounds were isolated, purified, identified, and characterized by MS, FT-IR, 1HNMR, APT, and 13C-NMR then the antituberculosis activity was examined by Microplate Alamar Blue Assay (MABA) method. Methods: This study was based on the articulation of carboxamide linkage bearing S-linkage in the core unit by reacting four different units, i.e., 2-(pyrimidin-2-ylthio)acetic acid, aromatic aldehyde, benzylamine and tertiary butyl isocyanide at RT in an atom economy route of synthesis. The desired product (5a- 5j) was synthesized via one-pot and Metal-free conditions. Results: Compounds (5a-5j) synthesized in good yields and compared to MIC values of Isoniazid 0.05 (μg/mL), Rifampicin 0.1 (μm/mL), and Ethambutol 1.56 (μg/mL) as a positive control. Conclusion: Synthesized compounds give excellent yield. Among the ten derivatives, compound 5f has comparable antituberculosis activity.

Development and evaluation of new oxindole derivatives as potential anti-tubercular agents

Tuberculosis (TB), which affects the lungs and other parts of the body, claims the lives of around 3 million people. Indolin-2-one derivatives were identified as a novel anti-tubercular series from Microplate Alamar Blue Assay (MABA) method, along with its synthesis, characterisation, molecular docking, and molecular dynamic simulations. The enzyme decaprenylphosphoryl-β-D-ribose 20-oxidase (DprE1) demonstrated high binding interaction energies associated with these compounds, which were investigated through the use of the docking technique. A conventional dynamic simulation study lasting 20 ns was used to assess the interaction's stability. The parameters derived from the trajectories of molecular dynamic simulation were computed and validated with respect to the stability of the protein-ligand complex under dynamic conditions. The absorption-distribution-metabolism-excretion (ADME) values are favourable for all of the synthesized compounds. After testing each novel compound for in vitro anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC27294), the most promising lead analogues were 9e (MIC: 1.56 μg/mL), 13b (MIC: 3.125 μg/mL), and 13e (MIC: 3.125 μg/mL). In this study, we have designed and produced new 5-substituted Oxindole derivatives as anti-tubercular drugs through the application of docking and molecular dynamic modeling. Given the increasing demand for novel antibiotics and the ensuing urgent need for novel anti-TB medications, we think the currently reported oxindole derivatives of DprE1 inhibitors present an excellent possibility for future optimization.

N-Substituted piperazine-coupled imidazo[2,1-b]thiazoles as inhibitors of Mycobacterium tuberculosis: Synthesis, evaluation, and docking studies.

An innovative series of N-substituted piperazine-linked imidazothiazole derivatives 7(a-x) were synthesized, and their antitubercular effectiveness was evaluated. A three-step reaction sequence involving the condensation of 1,3-dichloroacetone and thiourea, coupling with substituted piperazines to give the intermediates 5(a-d) and cyclization with substituted α-bromoacetophenones produced the desired imidazothiazole derivatives 7(a-x) in excellent yields. In vitro screening of new derivatives against Mycobacterium tuberculosis H37Rvresulted in 7k (minimum inhibitory concentration [MIC]: 0.78 μg/mL) and 7g and 7h (MIC: 1.56 μg/mL) as potent hit compounds. Further, the docking studies of the promising compounds7k, 7g, and 7h revealed that the best molecular interactions are with the DprE1 in complex with sulfonyl PBTZ of M. tuberculosis as the target protein (PDB ID: 6G83).

Decoding the structural integrity and multifunctional role of Era protein in the survival of Mycobacterium tuberculosis H37Rv

Era, a widely known GTP binding protein found in many organisms including prokaryotes and eukaryotes and plays a significant role in many fundamental cellular processes like cell growth, differentiation and signaling. In Mycobacterium tuberculosis (Mtb) H37Rv, Era protein had been proved as a GTPase protein but its structural and functional insights are still lacking. Through comparative analysis, structural modeling, docking and using various bioinformatic tools, a detailed investigation of Era was carried out to deduce the structure, function and residues involved in the activity of the protein. Intriguingly, docking results revealed high binding affinity of Era not only with GTP but also with ATP. Myristoylation modifications and phosphorylations on Era were predicted to possibly aid in regulating Era activity and localization; and also the role of Era in translation regulation was foreseen by showing its association with 16s rRNA. Moreover, point mutation of Era residues revealed the effect of W288G and K19G in highly destabilizing the protein structure and activity. Additionally, Era protein was docked with 25 GTPase/ATPase inhibitors, where, Dynasore inhibitor showed the highest affinity for the protein’s GTP binding sites and can be used for further drug trials to inhibit growth of mycobacteria. Communicated by Ramaswamy H. Sarma

Design, synthesis and biological evaluation of novel pyrido-[2,3-d]-pyrimidin-2-amine analogues as antimycobacterial agents

Thirty-eight novel Pyrido-[2,3-d]-pyrimidin-2-amine derivatives (P1-P38) were designed, synthesized, and their structures confirmed using analytical techniques viz.,1H NMR, 13C NMR, and mass spectrometry. Using the Microplate Alamar Blue Assay (MABA), the final derivatives, P1-P38, were tested for their anti-mycobacterial activity against the Mycobacterium tuberculosis (Mtb) H37Rv strain. Amongst all the assessed compounds, P35 displayed significant inhibition with MIC 7.18 μg/mL. The remaining compounds exhibited MIC from 18.11 to >100 μg/mL. The potent compounds with MIC 〈 40.96 μg/mL, were evaluated for toxicity on HEK293T a normal human embryonic kidney cell line. The most active compound P35 exhibited a selectivity index 〉 20, proving its selective behavior towards Mtb H37Rv strain than human cells. To further evaluate the binding pattern in the active site of Thymidylate Kinase (TMPK) from Mtb (PDB-1G3U), a molecular docking analysis of compound P35 was performed using the glide module of Schrodinger software. Finally, molecular dynamics simulations were performed for 100 ns in order to elucidate the stability, confirmation, and intermolecular interactions of the co-crystal ligand and significantly active compound P35 on the selected target protein.

Dysregulated cysteine metabolism leads to worsened liver pathology in diabetes-tuberculosis comorbid condition

Diabetes mellitus (DM) is a risk factor for developing active tuberculosis (TB) with a 3-fold increase in susceptibility and a 4-fold higher relapse rate. With increasing DM prevalence in TB endemic regions, understanding pathophysiological changes associated with DM-TB comorbidity is imperative. In this study, streptozotocin (STZ)-induced DM C57BL/6 mice were aerosol infected with low dose (100-120 CFU) Mycobacterium tuberculosis H37Rv. At 3 weeks post infection (w.p.i.), multiple tissue mycobacterial load and metabolites were profiled. The liver proteome of DM-TB and controls were analyzed using quantitative proteomics, and multi-omics data were integrated. DM-TB mice showed dysregulated multi-tissue (lungs, liver, brain, kidney and thigh muscle) metabolism. In contrast, the mycobacterial burden in the lung, spleen and liver was similar at 3 w.p.i. in DM-TB and TB groups. Enrichment analysis of deregulated liver metabolites (n=20; log2DM-TB/TB>±1.0) showed significant perturbation in cysteine-methionine, glycine-serine, BCAA and fatty acid metabolism. Sixty out of 1660 identified liver proteins showed deregulation (log2DM-TB/TB>±1.0) and contributed from perturbed cysteine-methionine metabolism corroborating metabolomics data. In addition, amino acid biosynthesis, retinol metabolism and polyol biosynthetic process were also differentially enriched in the livers of DM-TB groups. Global correlation analysis of liver metabolome and proteome data showed a strong association between aspartic acid, pyruvic acid, leucine and isoleucine with CYP450 enzymes involved in retinol metabolism, while iminodiacetic acid, isoleucine and γ-aminobutyric acid (GABA) strong positive correlation involved in cysteine metabolism. Targeting perturbed cysteine metabolism using micro molecules, like DL-Propargylglycine, might help prevent liver damage in DM-TB comorbid conditions.

Optimization, characterization, and cytotoxicity studies of novel anti-tubercular agent-loaded liposomal vesicles

The treatment of tuberculosis is still a challenging process due to the widespread of pathogen strains resistant to antibacterial drugs, as well as the undesirable effects of anti-tuberculosis therapy. Hence, the development of safe and effective new anti-antitubercular agents, in addition to suitable nanocarrier systems, has become of utmost importance and necessity. Our research aims to develop liposomal vesicles that contain newly synthesized compounds with antimycobacterial action. The compound being studied is a derivative of imidazo-tetrazine named 3-(3,5-dimethylpyrazole-1-yl)-6-(isopropylthio) imidazo [1,2-b] [1,2,4,5] tetrazine compound. Several factors that affect liposomal characteristics were studied. The maximum encapsulation efficiency was 53.62 ± 0.09. The selected liposomal formulation T8* possessed a mean particle size of about 205.3 ± 3.94 nm with PDI 0.282, and zeta potential was + 36.37 ± 0.49 mv. The results of the in vitro release study indicated that the solubility of compound I was increased by its incorporation in liposomes. The free compound and liposomal preparation showed antimycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC 27294) at MIC value 0.94–1.88 μg/ml. We predict that the liposomes may be a good candidate for delivering new antitubercular drugs.

Synthesis, Antioxidant and Antituberculosis Evaluation of Eugenol Derivatives from Mannich Condensation

AbstractMannich bases are interesting class of molecules thanks to their various pharmacological properties. This paper presents the synthesis and characterization of eugenol derivatives following Mannich condensation. The in vitro antituberculosis activity of the synthesized derivatives was evaluated by the Resazurin microtiter assay (REMA). The 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging and ferrous cation (FeCl2) chelating tests were used to estimate the antioxidant capacity. All eugenol Mannich bases inhibited the Mycobacterium tuberculosis (Mtb) H37Rv growing. Those of 2‐dimethylaminomethyl‐6‐methoxy‐4‐propenylphenol (1) and 2‐methoxy‐4‐propenyl‐6‐pyrrolidinylmethylphenol (4) were the most active at 10 μg/mL. Additionally, significant antioxidant profile was exhibited by the synthesized derivatives, especially for 2‐dicyclohexylaminomethyl‐6‐methoxy‐4‐propenylphenol (5) that showed an antiradical activity of EC50=20 μg/mL, twice as strong as that of eugenol precursor, and for 2‐methoxy‐6‐methylpiperazinylmethyl‐4‐propenylphenol (3) and compound 4, which were promising iron chelators with EC50 of 0.016 and 0.018 mg/mL, respectively, better than EDTA standard. The molecular docking experiments on two different antituberculosis receptors showed excellent binding affinity of compounds 4 and 5 into the active site of pantothenate kinase (PanK, type I), suggesting PanK as potential molecular target. These encouraging findings showed the importance of Mannich reaction for the development of antitubercular candidates and the improvement of natural products bioactivity.