Mycobacterium Tuberculosis H37Rv Strain Research Articles

2,3,5‐Trisubstituted Thiazolidinone Derivatives as Potential Antimicrobial and Antitubercular Agents and In Silico Studies

AbstractA series of novel 2,3,5‐trisubstituted thiazolidinone derivatives was designed and synthesized. Compounds were tested for their antimicrobial and antitubercular activities. Compounds 3‐(2,4‐difluorobenzyl)‐5‐[(5‐methylfuran‐2‐yl)methylidene]‐2‐(phenylimino)‐1,3‐thiazolidin‐4‐one (5 c) and 3‐(2,4‐difluorobenzyl)‐2‐((3‐fluorophenyl)imino)‐5‐((Z)‐4‐hydroxybenzylidene) thiazolidin‐4‐one (6 f) exhibited remarkable antimicrobial activity against Klebsiella pneumoniae and Escherichia coli respectively. All compounds except 3‐(2,4‐difluorobenzyl)‐5‐((3‐(4‐fluorophenyl)‐1‐phenyl‐1H‐pyrazol‐4‐yl)methylene)‐2‐(phenylimino)thiazolidin‐4‐one (5 a) and (6 f) exposed excellent antitubercular activity in comparison with the standard drugs against H37RV strain of Mycobacterium tuberculosis (ATCC No‐ 27294). In addition, molecular docking and dynamic simulations studies were performed with E. coli Mur B (EMB) (PDB ID: 2Q85), Aspergillus fumigatus sterol 14‐alpha demethylase (ASD) (PDB ID: 4UYM) and Mycobacterium tuberculosis pantothenate synthetase (MPS) (PDB ID: 3IVX) proteins against all compounds and the most potent compound (5 c) displayed higher binding proficiency. These compounds may serve as lead compounds for further optimization to achieve promising therapeutic properties.

Lanthanide furoate complexes as promising systems with double effects – From suppression of mycobacteria to potential bioimaging

Several ternary complexes of rare earth ions (Gd3+, Eu3+, Sm3+) with 3-furoic (H3fur) / 5-nitro-2-furoic (Hnfur) acids and 1,10-phenanthroline (phen) have been synthesized. According to the X-ray data the resulting complexes can be divided into two groups − heterocarboxylate [Ln2(3fur)4(OAc)2(phen)2]·L and homocarboxylate complexes [Ln2(nfur)6(phen)2]·L (LnIII = Gd (1, 2), Eu (3, 4), Sm (5, 6, 7); L = 4EtOH (1–4), 4MeOH (5), H2O (7)). The stability of the complexes 1–6 in solutions was studied by recording electronic absorption spectra for two days. Optical properties of the complexes 1–6 were studied by recording absorption, excitation and luminescence spectra. The study of antibacterial properties 1–7 showed high activity of complexes in vitro against non-pathogenic Mycolicibacterium smegmatis. For the most active 3, antibacterial activity against the reference strain Mycobacterium tuberculosis H37Rv was determined (minimum inhibitory concentration (MIC) up to 12.5 μg/mL)..

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.

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.

Exploring rhodanine linked enamine-carbohydrazide derivatives as mycobacterial carbonic anhydrase inhibitors: Design, synthesis, biological evaluation, and molecular docking studies.

With the rise of multidrug-resistant tuberculosis, the imperative for an alternative and superior treatment regimen, incorporating novel mechanisms of action, has become crucial. In pursuit of this goal, we have developed and synthesized a new series of rhodanine-linked enamine-carbohydrazide derivatives, exploring their potential as inhibitors of mycobacterial carbonic anhydrase. The findings reveal their efficacy, displaying notable selectivity toward the mycobacterial carbonic anhydrase 2 (mtCA 2) enzyme. While exhibiting moderate activity against human carbonic anhydrase isoforms, this series demonstrates promising selectivity, positioning these compounds as potential antitubercular agents. Compound 6d was the best one from the series with a Ki value of 9.5 µM toward mtCA 2. Most of the compounds displayed moderate to good inhibition against the Mtb H37Rv strain; compound 11k showed a minimum inhibitory concentration of 1 µg/mL. Molecular docking studies revealed that compounds 6d and 11k show metal coordination with the zinc ion, like classical CA inhibitors.

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.

Discovery of 2,9-diaryl-6-carbamoylpurines as a novel class of antitubercular agents

A series of novel 9-alkyl/aryl-2-aryl-6-carbamoylpurines were synthesized, and their activity against Mycobacterium tuberculosis strain H37Rv was assessed. The SAR analysis on the first set of derivatives, with an alkyl or aryl unit at N-9 and a phenolic unit at C-2, showed that the activity depends on the purine ring substituents at N-9 and C-2. A phenyl group at N-9 combined with a 3-hydroxyphenyl or 4-hydroxyphenyl at C-2 improve the activity. The most active compound of this set has a phenyl group at N-9 and a 4-hydroxyphenyl group at C-2, displaying an IC90 = 1.2 μg/mL and a selectivity index higher than 25.5. This compound served as a Hit to design the second set of derivatives. A phenyl group at N-9 was maintained, and the group at C-2 was diversified. The SAR analysis showed that the aryl unit at C-2 must have an oxygen or nitrogen atom bonded in the para position. A proton, a small alkyl or a substituted aryl group may also be bonded to the oxygen. The compound with the 4-methoxyphenyl group at C-2, 1Bd, exhibits the highest activity with an IC90 < 0.19 μg/mL. This compound is highly potent against M. tuberculosis strain H37Rv and non-toxic for VERO mammalian cells with an SI > 153.8. Compound 1Bd was also non-cytotoxic against primary macrophage cultures at IC90, 2xIC90, and 10xIC90 and significantly reduced the bacterial load in M. tuberculosis-infected macrophages at the same concentrations. Compound 1Bd showed a favorable pharmacokinetic profile when administered orally, with major lung and liver accumulation. In vivo antimycobacterial efficacy of 1Bd was tested at 25 mg/kg. At the tested regimen, a decrease in bacterial burden was observed in the liver. Optimization of the treatment regimen should be performed to fully potentiate the in vivo efficacy of our lead molecule, particularly in the lung, the main target organ of M. tuberculosis.

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.

PCR Development for Analysis of Some Type II Toxin-Antitoxin Systems, relJK, mazEF3, and vapBC3 Genes, in Mycobacterium tuberculosis and Mycobacterium bovis.

Toxin-Antitoxin (TA) systems are some small genetic modules in bacteria that play significant roles in resistance and tolerance development to antibiotics. Whole genome sequencing (WGS) is an effective method to analyze TA systems in pathogenic Mycobacteria. However, this study aimed to use a simple and inexpensive PCR-Sequencing approach to investigate the type II TA system. Using data from the WGS of Mycobacterium tuberculosis (M. tuberculosis) strain H37Rv and Mycobacterium bovis (M. bovis) strain BCG, primers specific to the relJK, mazEF3, and vapBC3 gene families were designed by Primer3 software. Following that, a total of 90 isolates were examined using the newly developed PCR assay, consisting of 64M. tuberculosis and 26M. bovis isolates, encompassing both 45 rifampin-sensitive and 45 rifampin-resistant strains. Finally, 28 isolates (including 14 rifampin-resistant isolates) were sent for sequencing, and their sequences were aligned and compared to the mentioned reference sequences. The amplicons size of mazEF3, relJK, and vapBC3 genes were 825, 875, and 934 bp, respectively. Furthermore, all tested isolates showed the specific amplicons for these TA families. To evaluate the specificity of the primers, PCR was performed on S. aureus and E.coli isolates. None of the examined samples had the desired amplicons. Therefore, the primers had acceptable specificity. The results indicated that the developed PCR-Sequencing approach can be used to effectively investigate certain types of TA systems. Considering high costs of WGS and difficulty in interpreting its results, such a simple and inexpensive method is beneficial in the evaluation of TA systems in Mycobacteria.

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.

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.

Discovery of 1,2,3-triazole incorporated indole-piperazines as potent antitubercular agents: Design, Synthesis, In vitro biological evaluation, molecular docking and ADME studies

In this report, a library consisting of three sets of indole-piperazine derivatives was designed through the molecular hybridization approach. In total, fifty new hybrid compounds (T1-T50) were synthesized and screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain (ATCC-27294). Five (T36, T43, T44, T48 and T49) among fifty compounds exhibited significant inhibitory potency with the MIC of 1.6 µg/mL, which is twofold more potent than the standard first-line TB drug Pyrazinamide and equipotent with Isoniazid. N-1,2,3-triazolyl indole-piperazine derivatives displayed improved inhibition activity as compared to the simple and N-benzyl indole-piperazine derivatives. In addition, the observed activity profile of indole-piperazines was similar to standard anti-TB drugs (isoniazid and pyrazinamide) against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa strains, demonstrating the compounds’ selectivity towards the Mycobacterium tuberculosis H37Rv strain. All the active anti-TB compounds are proved to be non-toxic (with IC50 > 300 μg/mL) as verified through the toxicity evaluation against VERO cell lines. Additionally, molecular docking studies against two target enzymes (Inh A and CYP121) were performed to validate the activity profile of indole-piperazine derivatives. Further, in silico-ADME prediction and pharmacokinetic parameters indicated that these compounds have good oral bioavailability.

Green synthesis and in-vitro screening of 3-((4-(arylideneamino)phenyl) imino)indolin-2-one derivatives antimycobacterial agents

In this research article, we attempted to synthesize some new isatin derivatives, 3-((4-(arylideneamino)phenyl)imino)indolin-2-ones (2a-2g) by Schiff\'s base reaction under microwave technique. The structural characterizations of synthesized compounds were done by using different analytical techniques such as IR, 1HNMR, mass spectrometry, and elemental analysis. We aim to develop new compounds with improved antimycobacterial activities. These title compounds were screened for their antimycobacterial activity against the Mycobacterium tuberculosis H37Rv strain by using the microplate Alamar blue dye assay (MABA) method. All title compounds showed significant antimycobacterial activity. Compound 2g was found most potent compound with a MIC value of 6.25 µg/mL among all tested compounds when compared with standard drugs streptomycin (6.25µg/mL) and isoniazid (6.25 µg/mL).

NK-derived exosome miR-1249-3p inhibits Mycobacterium tuberculosis survival in macrophages by targeting SKOR1

Murine Natural Killer cells were cultivated in vitro to isolate NK-derived exosomes. Subsequent quantification via qPCR confirmed enrichment of miR-1249-3p. Ana-1 murine macrophages were cultured in vitro and subsequently inoculated with Mycobacterium tuberculosis (MTB) strain H37Rv. NK-exo and NK-exo miR-1249-3p were separately applied to the infection model, followed by immunological assays conducted post-48-hour co-culture. Western blot analyses corroborated that NK-exo exhibited exosomal marker proteins Granzyme A (GzmA), Granzyme B (GzmB), and Perforin (PFN), alongside a notable enrichment of miR-1249-3p. Functionally, NK-exo augmented the expression levels of Caspase-9,-8, and -3, as well as PARP, while attenuating the expression of NLRP3, ASC, and Cleaved-Caspase-1. Furthermore, qPCR demonstrated an up-regulation of Caspase-9, -8, and -3, along with pro-apoptotic factors Bax and Bid, and a concomitant down-regulation of the anti-apoptotic factor Bcl-2. The expression levels of inflammatory markers ASC, NLRP3, Cleaved-Caspase-1, and IL-1β were concomitantly decreased. ELISA findings indicated diminished levels of TNF-α and ROS secretion. NK-exo miR-1249-3p specifically targeted and attenuated the expression of SKOR-1, engendering up-regulation of apoptosis-associated proteins and down-regulation of inflammation-related proteins, consequently affecting cellular fate.Our empirical evidence substantiates that NK-exo induces macrophage apoptosis, thereby mitigating MTB survival. Furthermore, NK-exo miR-1249-3p directly targets and inhibits SKOR-1 expression, leading to macrophage apoptosis and consequently hampering the proliferation of MTB. The data implicate the potential therapeutic relevance of NK-exo and miR-1249-3p in managing drug-resistant tuberculosis.

Omadacycline pharmacokinetics/pharmacodynamics and efficacy against multidrug-resistant Mycobacterium tuberculosis in the hollow fiber system model.

Seventy-five years ago, first-generation tetracyclines demonstrated limited efficacy in the treatment of tuberculosis but were more toxic than efficacious. We performed a series of pharmacokinetic/pharmacodynamic (PK/PD) experiments with a potentially safer third-generation tetracycline, omadacycline, for the treatment of multidrug-resistant tuberculosis (MDR-TB). Mycobacterium tuberculosis (Mtb) H37Rv and an MDR-TB clinical strain (16D) were used in the minimum inhibitory concentration (MIC) and static concentration-response studies in test tubes, followed by a PK/PD study using the hollow fiber system model of TB (HFS-TB) that examined six human-like omadacycline doses. The inhibitory sigmoid maximal effect (Emax) model and Monte Carlo experiments (MCEs) were used for data analysis and clinical dose-finding, respectively. The omadacycline MIC for both Mtb H37Rv and MDR-TB clinical strain was 16 mg/L but dropped to 4 mg/L with daily drug supplementation to account for omadacycline degradation. The Mycobacteria Growth Indicator Tube MIC was 2 mg/L. In the test tubes, omadacycline killed 4.39 log10 CFU/mL in 7 days. On Day 28 of the HFS-TB study, the Emax was 4.64 log10 CFU/mL, while exposure mediating 50% of Emax (EC50) was an area under the concentration-time curve to MIC (AUC0-24/MIC) ratio of 22.86. This translates to PK/PD optimal exposure or EC80 as AUC0-24/MIC of 26.93. The target attainment probability of the 300-mg daily oral dose was 90% but fell at MIC ≧4 mg/L. Omadacycline demonstrated efficacy and potency against both drug-susceptible and MDR-TB. Further studies are needed to identify the omadacycline effect in combination therapy for the treatment of both drug-susceptible and MDR-TB.

In vitro and in silico exploration of newly synthesized triazolyl- isonicotinohydrazides as potent antitubercular agents

In the present study, we have reported the synthesis of novel isoniazid-triazole derivatives (4a-r), via the click chemistry approach. The synthesized isoniazid-triazole derivatives have potent in vitro antitubercular activity against the Mycobacterium tuberculosis (MTB) H37Rv strain. Among these compounds, 4b, 4f, 4g, 4j, 4k, 4m, 4o, 4p, and 4r were found to be the most active ones with a MIC value of 0.78 μg/mL. This activity is better than ciprofloxacin (MIC value = 1.56 μg/mL) and ethambutol (MIC value = 3.12 μg/mL). The compounds, 4a, 4c, 4d, 4e, 4h, 4i, 4l, and 4n have displayed activity equal to ciprofloxacin (MIC value = 1.56 μg/mL). The cytotoxicity of the active isoniazid-triazole derivatives was studied against RAW 264.7 cell line by MTT assay at 25 μg/mL concentration and no toxicity was observed. Moreover, in-vitro results were supported by in-silico studies with the known antitubercular target (PanK). The drug-likeness, density functional study, molecular docking, and molecular dynamics simulation studies of isoniazid-triazole derivatives validated the ability to form a stable complex with Pantothenate kinase (PanK), which will result in inhibiting the Pantothenate kinase (PanK). Therefore, the results obtained indicate that this class of compounds may offer candidates for future development, and positively provide drug alternatives for tuberculosis treatment.Communicated by Ramaswamy H. Sarma

Design, synthesis and molecular dynamic studies of novel imidazo/pyrido-pyrimidine clubbed ethyl-1,2,3,4-tetrahydro-4-phenylpyrimidine-5-carboxylate derivatives as potent anti-tubercular agents

A small library of substituted ethyl-1,2,3,4-tetrahydro-4-phenylpyrimidine-5-carboxylate was designed and synthesized. All the characterized molecules were screened for their anti-tubercular activity using the H37Rv strain of Mycobacterium tuberculosis (Mtb). The compounds 5c, 5d, 5f, 5h, and 5k showed equipotent activity (MIC 3.12 µg/mL), compounds 5b, 5e, 5g, 5i, and 5j were more potent (MIC 1.6 µg/mL), whereas, 5a and 5l shown moderate activity (MIC 6.25 µg/mL). The potent inhibitory activity of screened compounds was rationalized with in-silico molecular modeling studies against the Mtb-dihydrofolate reductase (DHFR) enzyme. Compound 5i displayed a good docking score of −8.56 Kcal/mole with H-bond and hydrophobic interactions. These interactions revealed the stability of the complex which in turn determined the potent inhibitory effect. To get in-depth mechanistic insight into the inhibitory effect and to assess the stability of the ligand–protein complex, a molecular dynamics (MD) simulation study was performed. The RMSD and RMSF values obtained by the MD simulation study were 2.39 Å and 0.92 Å, respectively. The obtained values suggested that the drug–ligand complex maintained the stability over entire 100 ns run and the molecule did not fluctuate. The H-bond and hydrophobic interactions displayed in molecular docking studies were found to be retained in the MD simulation run. The obtained MD simulation values indicate that the complex was stable and rationalize the potent inhibitory effect. The drug-likeliness properties of potent compounds were calculated and the values thus obtained suggested that the molecule 5i has drug-likeliness properties and complies with Lipinski's rule of five/Ro3. Hence, the identified compounds can be taken into further stages of drug discovery processes.

ADME, Synthesis and Antimycobacterial Activity of 1,2,4-Triazol-3-thiol Linked Phenylacetamide Derivatives

Background:: Tuberculosis (TB) is caused by Mycobacterium tuberculosis and is one of the most contagious and fatal human pathogens which necessitates the development of modified existing drugs or derivatives with action against novel targets. Aims and Objectives:: In the present work, we have explored a few, 2-(5-(substituted)-4H-1,2,4-triazole-2-ylthio)-N-(substituted) phenyl acetamide (5A-5E) derivatives as anti-TB. Materials and Methods:: On the basis of SAR were synthesized and screened against Mycobacterium tuberculosis H37Rv using MABA assay. Their ADME properties were also checked. Results:: ADME analysis showed results comparable with standard drug (rifampicin). Derivative 5D turned out to be the most active amongst all the derivatives with MIC of 0.8μg/ml, comparable to standard drugs like rifampicin(0.8μg/ml) and streptomycin(0.8μg/ml). Conclusion:: All five compounds have shown excellent inhibitory activity (1.6μg/ml) against the Mycobacterium tuberculosis H37Rv strain. Compound 5D shows a promising activity (0.8μg/ml) as compared to standard drugs and also it has shown the highest docking score. Literature search has revealed the presence of 1,2,4-triazole derivatives linked to aromatic link and possessing amide linkage and the presence of Sulphur atom in the most active derivatives, which supports our designed compounds. Based on these findings, further derivatives would be synthesized and explored for their role in tuberculosis.

Repurposing Azoles to Resolve Serotogenic Toxicity Associated with Linezolid to Combat Multidrug-Resistant Tuberculosis.

Serotogenic toxicity is a major hurdle associated with Linezolid in the treatment of drug-resistant tuberculosis (TB) due to the inhibition of monoamine oxidase (MAO) enzymes. Azole compounds demonstrate structural similarities to the recognized anti-TB drug Linezolid, making them intriguing candidates for repurposing. Therefore, we have repurposed azoles (Posaconazole, Itraconazole, Miconazole, and Clotrimazole) for the treatment of drug-resistant TB with the anticipation of their selectivity in sparing the MAO enzyme. The results of repurposing revealed that Clotrimazole showed equipotent activity against the Mycobacterium tuberculosis (Mtb) H37Rv strain compared to Linezolid, with a minimal inhibitory concentration (MIC) of 2.26 μM. Additionally, Clotrimazole exhibited reasonable MIC50 values of 0.17 μM, 1.72 μM, 1.53 μM, and 5.07 μM against the inhA promoter+, katG+, rpoB+, and MDR clinical Mtb isolates, respectively, compared to Linezolid. Clotrimazole also exhibited 3.90-fold less inhibition of MAO-A and 50.35-fold less inhibition of MAO-B compared to Linezolid, suggesting a reduced serotonergic toxicity burden.

Asiaticoside A for the modulation of 1-TbAd- a potential target and ligand for extensive drug resistance Mycobacterium tuberculosis

In nature, terpene nucleosides are relatively rare, with 1-tuberculosinyladenosine (1-TbAd) being an exclusive feature of Mycobacterium tuberculosis (Mtb). The convergence of nucleosides and terpene pathways in the Mtb complex appears to have emerged late in its evolutionary history. 1-TbAd (PDB ID: 3WQK) is a prominent chemical marker for Mtb and may contribute to its virulence-related properties when exported extracellularly. We gathered a comprehensive set of 270 phytochemicals from diverse Ayurvedic texts and treatment traditions. Subsequently, we conducted structure-based molecular docking analyses to identify compounds exhibiting the strongest binding affinity for 1-TbAd, highlighting their potential as drug candidates. These selected compounds were further subjected to an in-vitro growth inhibition assay against the reference strain Mycobacterium tuberculosis h37rv. Among the candidates, Asiaticoside A (ASA) emerged as a promising candidate from the pool of 270 compounds. To assess the impact of ASA on 1-TbAd expression, we employed a PCR-based mRNA expression assay, revealing ASA's ability to downregulate 1-TbAd expression in extensively drug-resistant MTb strains. Remarkably, the conventional drug rifampin showed no such effectiveness in our experiments. We further conducted molecular dynamic simulations to explore the interaction between ASA and 1-TbAd in a cellular-like environment, confirming the stability of their interaction. Also, we predicted ASA's stability toward causing inducing the random mutations in the target gene. With this, we propose a novel target and its modulator to treat extensively drug-resistant MTB.Graphical