Interactive effect of oral anti-hyperglycaemic or anti-hypertensive drugs on the inhibitory and bactericidal activity of first line anti-TB drugs against M. tuberculosis.

Co-existence of life style disorders, like, Diabetes or Hypertension, increases risk of, treatment failure, deaths and developing drug-resistant TB. Concomitant administration of drugs to treat dual/multi-morbidities may alter their effectiveness, in additive/synergistic or adverse/antagonistic manner. We evaluated interactive effect of 7 anti-hyperglycaemic (HG) and 6 anti-hypertensive (HT) drugs on the inhibitory (MICs) and bactericidal (% killing of intracellular bacilli) activities of anti-TB drugs, Isoniazid (INH), Rifampicin (RFM), Ethambutol (EMB) and Streptomycin (STR) against M. tuberculosis. Five anti-HG drugs, namely, Acarbose, Acetohexamide, Glyburide, Repaglinide and Sitagliptin imparted either 'additive' or 'no effect' on the activities (inhibition or % killing) of all the four anti-TB drugs, as evident by their lower FICs (Fractional Inhibitory concentrations) and higher bacterial killing in combination. Metformin and Rosiglitazone, however, exerted adverse effect on the Ethambutol (FICs >2.0). All the six anti-HT drugs, namely, Atenolol, Hydrochlorothiazide, Ramipril, Valsartan, Nifedipine and Verapamil exerted either 'additive'/'synergistic' or 'no effect' on the activities of anti-TB drugs. These findings may help clinicians to select safe and helpful anti-HG or anti-HT drugs for TB patients, if, suffering with diabetes or hypertension like co-morbidities and receiving DOTs (a set regimen for the treatment of TB based on the WHO guidelines).

Synthesis and Structural Activity Relationship Study of Ursolic Acid Derivatives as Antitubercular Agent.

OBJECTIVE: The chemical transformation of ursolic acid (UA) into novel C-3 aryl ester derivatives and in vitro and silico assessment of their antitubercular potential. BACKGROUND: UA is a natural pentacyclic triterpenoid with many pharmacological properties. Semisynthetic UA analogs have demonstrated enhanced anticancer, antimalarial, and antifilarial properties in our previous studies. METHOD: The C-30 carboxylic group of previously isolated UA was protected, and various C-3 aryl ester derivatives were semi-synthesized. The agar dilution method was used to evaluate the in vitro antitubercular efficacy of Mycobacterium tuberculosis (Mtb) H37Ra. In silico docking studies of the active derivative were carried out against Mtb targets, catalase peroxidase (PDB: 1SJ2), dihydrofolate reductase (PDB: 4M2X), enoyl-ACP reductase (PDB: 4TRO), and cytochrome bc1 oxidase (PDB: 7E1V). RESULTS: The derivative 3-O-(2-amino,3-methyl benzoic acid)-ethyl ursolate (UA-1H) was the most active among the eight derivatives (MIC1 2.5 µg/mL) against Mtb H37Ra. Also, UA-1H demonstrated significant binding affinity in the range of 10.8-11.4 kcal/mol against the antiTb target proteins, which was far better than the positive control Isoniazid, Ethambutol, and co-crystallized ligand (HEM). Moreover, the predicted hit UA-1H showed no inhibition of Cytochrome P450 2D6 (CYP2D6), suggesting its potential for favorable metabolism in Phase I clinical studies. CONCLUSION: The ursolic acid derivative UA-1H possesses significant in vitro antitubercular potential with favorable in silico pharmacokinetics. Hence, further in vivo assessments are suggested for UA-1H for its possible development into a secure and efficient antitubercular drug.

Design and Synthesis of Quinazolinone-Triazole Hybrids as Potent Anti-Tubercular Agents.

A straightforward and convenient methodology has been developed for the reaction of 2-aminobenzamide and carbonyls affording 2,3-dihydroquinazolin-4(1H)-ones using aqueous solution of [C12Py][FeCl3Br]. The developed methodology was applied for the synthesis of 25 quinazolinone-triazole hybrids followed by evaluation of their in vitro anti-tubercular (TB) activity. The results revealed that 8 quinazolinone-triazole hybrids displayed promising activity having MIC values of 0.78-12.5 µg/mL. The compound 3if with MIC 0.78 µg/mL was found to be the lead nominee among the series, better than Ethambutol, a first line anti-TB drug and comparable with Rifampicin. The active compounds with MIC values ≤ 6.25 µg/mL were subjected to in vitro cytotoxicity and found nontoxic. In drug-drug interaction, compounds 3ia and 3ii interacted synergistically with all the three anti-TB drugs, INH, RFM, and EMB. Other 3 compounds interacted either in synergistic or additive manners. Important information on the binding interaction of the target compounds with the active sites of 1DQY Antigen 85C from Mycobacterium tuberculosis and Enoyl acyl carrier protein reductase (InhA) enzymes was obtained from molecular docking studies. Screening of the drug-likeness properties and bioactivity score indicates that synthesized molecules could be projected as potential drug candidates. Based on the current study, quinazolinone-triazole hybrids framework can be useful in drug development for TB.

Brevifoliol and its Analogs: A New Class of Anti-tubercular Agents.

Brevifoliol is an abeo-taxane isolated from the Taxus wallichiana needles; eighteen semisynthetic esters derivatives of brevifoliol were prepared by Steglich esterification and screened for their anti-tubercular potential against Mycobacterium tuberculosis H37Ra avirulent strain. The 3- [chloro (7)] and 3, 5-[dinitro (8)] benzoic acid ester derivatives were most active (MIC 25 ug/ml) against the pathogen. Further, in silico docking studies of the active derivative 7 with mycobacterium enzyme inhA (enoyl-ACP reductase) gave the LibDock score of 152.68 and binding energy of -208.62 and formed three hydrogen bonds with SER94, MET98, and SER94. Similarly, when derivative 8 docked with inhA, it gave the LibDock score of 113.55 and binding energy of -175.46 and formed a single hydrogen bond with GLN100 and Pi-interaction with PHE97. On the other hand, the known standard drug isoniazid (INH) gave the LibDock score of 61.63, binding energy of -81.25 and formed one hydrogen bond with ASP148. These molecular docking results and the way of binding pattern indicated that compounds 7 and 8 bound well within the binding pocket of inhA and showed a higher binding affinity than the known drug isoniazid. Additionally, both the derivatives (7 and 8) showed no cytotoxicity, with CC50 195.10 and 111.36, respectively towards the mouse bone marrow-derived macrophages.

A Simple Work-Up-free, Solvent-free Approach to Novel Amino Acid Linked 1,4-Disubstituted 1,2,3-Triazoles as Potent Antituberculosis Agents.

An efficient, green strategy for synthesis of 1,4-disubstituted-1,2,3-triazole has been developed using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) acetate ionic liquid (200 µL) under a solvent- and external base-free condition. This protocol is further applied for the synthesis of novel amino acid containing 1,2,3-triazole molecules, which were then evaluated for potential antitubercular and antibacterial activities. Cytotoxicity assay of the compounds was also performed. In silico analysis of the promising compounds selected through experimental analysis was thereafter performed for visualizing molecular interactions and predicting binding affinities between our synthesized molecules, which exhibited good activity in experimental studies and the DprE1 target protein of Mycobacterium tuberculosis. Durg-likeness studies also show potential of the synthesized molecules as drug candidates.

Design, synthesis, in vitro and in silico studies of 2, 3-diaryl benzofuran derivatives as antitubercular agents.

As a part of our drug discovery program for anti-tubercular agents, a total of seventeen 2, 3-diaryl benzofuran hybrids were designed, synthesized and screened for their anti-tubercular potential against Mycobacterium tuberculosis H37Ra avirulent strain. Out of seventeen, four derivatives showed significant activity against M. tuberculosis H37Ra avirulent strain (ATCC 25177) with MIC value ranging from 12.5 to 50 µg/mL but out of four, one derivative (9E) was significantly active (MIC 12.5 µg/mL), which was further supported by the molecular docking energy (-8.4 kcal/mol) with respect to the first line anti-tubercular drug, isoniazid (-6.2 kcal/mol) on the target Polyketide Synthase-13. All the derivatives were also evaluated for their cytotoxicity against the normal lung cell line L-132 by the MTT assay and no toxicity was observed up to 27.4 µg/mL concentration. This report on the antitubercular potential of benzofuran derivatives may be of great help in anti-tubercular drug development.

Synthesis and Biological Studies of Dodecameric Cationic Antimicrobial Peptides Containing Tetrahydrofuran Amino Acids.

We report here a concise route to synthesize various stereoisomers of tetrahydrofuran amino acids (TAAs) and the synthesis of TAA-containing linear cationic dodecapeptides. Some of these linear peptides show slightly better antimicrobial activities than their tetra- and octameric congeners, but no activity against Mycobacterium tuberculosis, for which octapeptides exhibited by far the best results; this implies that antibacterial activity is dependent on the length of these linear peptides. All the dodecapeptides described here were found to be toxic in nature against Vero cells. The study helps to delineate the optimal length of this series of linear peptides and select potential leads in the development of novel cationic peptide-based antibiotics.

In Vitro, In Silico and Ex Vivo Studies of Dihydroartemisinin Derivatives as Antitubercular Agents.

INTRODUCTION: As a part of our drug discovery program for anti-tubercular agents, dihydroartemisinin (DHA-1) was screened against Mtb H37Rv, which showed moderate anti-tubercular activity (>25.0 µg/mL). These results prompted us to carry out the chemical transformation of DHA-1 into various derivatives and study their antitubercular potential. MATERIALS AND METHODS: DHA-1 was semi-synthetically converted into four new acyl derivatives (DHA-1A - DHA-1D) and in-vitro evaluated for their anti-tubercular potential against Mycobacterium tuberculosis H37Rv virulent strain. The derivatives, DHA-1C (12-O-(4-nitro) benzoyl; MIC 12.5 µg/mL) and DHA-1D (12-O-chloro acetyl; MIC 3.12µg/mL) showed significant activity against the pathogen. RESULTS: In silico studies of the most active derivative (DHA-1D) showed interaction with ARG448 inhibiting the mycobacterium enzymes. Additionally, it showed no cytotoxicity towards the Vero C1008 cells and Mouse bone marrow derived macrophages. CONCLUSION: DHA-1D killed 62% intracellular M. tuberculosis in Mouse bone marrow macrophage infection model. To the best of our knowledge, this is the first-ever report on the antitubercular potential of dihydroartemisinin and its derivatives. Since dihydroartemisinin is widely used as an antimalarial drug; these results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non-toxic natural product.

Dihydroartemisinin and its Analogs: A New Class of Antitubercular Agents.

BACKGROUND: Tuberculosis is one of the leading causes of mortality worldwide. Resistance against the frontline anti-tubercular drugs has worsened the already alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-tubercular agents possessing novel modes of action. OBJECTIVE: Chemical transformation of dihydroartemisinin for anti-tubercular lead optimization. METHODS: Dihydroartemisinin, a metabolite of artemisinin was chemically converted into eight acyl derivatives and were evaluated for anti-tubercular potential against H37Rv virulent strain of Mycobacterium tuberculosis by agar-based proportion assay. Further, synergistic activity of 12-O-m-anisoyl dihydroartemisinin was also studied with the front-line anti-TB drugs, isoniazid and rifampicin. RESULTS: The results showed that all the derivatives were active but out of eight, 12-O-m-anisoyl dihydroartemisinin and 12-O-p-anisoyl dihydroartemisinin were significantly active (MIC 25.0 µg/mL). In synergistic activity evaluation, the 12-O-m-anisoyl dihydroartemisinin derivative showed reduction in MIC (by 1/8th, i.e. 3.12 µg/mL and that of rifampicin by »th, i.e. 0.05 µg/mL) with the front-line anti-TB drug, rifampicin. The sumfractional inhibitory concentration (Σ FIC) was 0.375. CONCLUSION: These results suggested a synergistic effect of the 12-O-m-anisoyl dihydroartemisinin with rifampicin and established its base for the development of anti-tubercular agents from an in-expensive and non-toxic natural product. To the best of our knowledge this is the first ever report on the anti-tubercular potential of dihydroartemisinin and its derivatives.

Synthesis and biological evaluation of novel 1,2,3-triazole derivatives as anti-tubercular agents.

A library of seventeen novel 1,2,3-triazole derivatives were efficiently synthesized in excellent yields by the popular 'click chemistry' approach and evaluated in vitro for their anti-tubercular activity against Mycobacterium tuberculosis H37Ra (ATCC 25177 strain). Among the series, six compounds exhibited significant activity with minimum inhibitory concentration (MIC) values ranging from 3.12 to 0.78µg/mL and along with no significant cytotoxicity against MBMDMQs (mouse bone marrow derived macrophages). Molecular docking of the target compounds into the active site of DprE1 (Decaprenylphosphoryl-ß-d-ribose-2'-epimerase) enzyme revealed noteworthy information on the plausible binding interactions.

Antitubercular activity of ZnO nanoparticles prepared by solution combustion synthesis using lemon juice as bio-fuel.

In this study, we report the synthesis, structural and morphological characteristics of zinc oxide (ZnO) nanoparticles using solution combustion synthesis method where lemon juice was used as the fuel. In vitro anti-tubercular activity of the synthesized ZnO nanoparticles and their biocompatibility studies, both in vitro and in vivo were carried out. The synthesized nanoparticles showed inhibition of Mycobacterium tuberculosis H37Ra strain at concentrations as low as 12.5µg/mL. In vitro cytotoxicity study performed with normal mammalian cells (L929, 3T3-L1) showed that ZnO nanoparticles are non-toxic with a Selectivity Index (SI) >10. Cytotoxicity performed on two human cancer cell lines DU-145 and Calu-6 indicated the anti-cancer activity of ZnO nanoparticles at varied concentrations. Results of blood hemolysis indicated the biocompatibility of ZnO nanoparticles. Furthermore, in vivo toxicity studies of ZnO nanoparticles conducted on Swiss albino mice (for 14days as per the OECD 423 guidelines) showed no evident toxicity.

S-Enantiomer of the Antitubercular Compound S006-830 Complements Activity of Frontline TB Drugs and Targets Biogenesis of Mycobacterium tuberculosis Cell Envelope.

A synthetic molecule S006-830, belonging to the class of thiophene-containing trisubstituted methanes, had shown good in vitro and in vivo bactericidal activity against drug-sensitive and drug-resistant Mycobacterium tuberculosis (Mtb). The molecule had also shown good druglike pharmacokinetic properties. However, S006-830 is a racemic mixture of two enantiomers, one of which could possess a better pharmacological profile than the other. We purified both the enantiomers on a chiral column and observed that S-enantiomer has a significantly higher inhibitory and cidal activity against Mtb than the R-enantiomer. Action of S-S006-830 was "synergistic" for rifampicin and "additive" for isoniazid and ethambutol. The combination of S-S006-830 and rifampicin produced 100% kill of Mtb within 8 days. In a chemical proteomics approach using matrix-bound compound to pull down its target protein(s) from Mtb membrane, FabG4 (ß-ketoacyl CoA reductase, EC 1.1.1.100) emerged as the most likely target for S-S006-830. In target validation assays, the compound exhibited 2-fold higher inhibitory concentration for an Mtb construct overexpressing FabG4. In addition, it inhibited mycolic acid biosynthesis and formation of biofilms by Mtb. Molecular docking of S-S006-830 with FabG4 was consistent with the experimental data. These results support the development of S-S006-830 as a novel lead against tuberculosis.

Correction to "S-Enantiomer of the Antitubercular Compound S006-830 Complements Activity of Frontline TB Drugs and Targets Biogenesis of Mycobacterium tuberculosis Cell Envelope".

[This corrects the article DOI: 10.1021/acsomega.7b01281.].

Intestinal Atresia: Experience at a Busy Center of North-West India.

Objective: To evaluate the presentation, management, complications and outcome of intestinal atresia (IA) managed at our center over a period of 1 year. Materials and methods: Records of patients of IA admitted in our center from January 2015 to December 2015 were retrospectively analyzed. Demographic data, antenatal history, presenting complaints, location (duodenal, jejunoileal, colonic) of atresia, surgery performed and peri-operative complications were noted. Results: Total 78 cases of IA were included in the analyses. Mean age and weight at the time of presentation was 5.8 days (range 0-50), and 1.9 kg (range 1.1-3.2), respectively. IA included duodenal atresia [DA (32)], jejuno-ileal atresia [JIA (40)], colonic atresia [CA (3)] and atresia at multiple-location (sites) in 3 cases. Ninety percent of patients underwent surgery within 5 to 20 hours of admission. All cases of DA except one underwent Kimura's diamond shaped duodeno-duodenostomy. One case with perforated duodenal web underwent duodenotomy with excision of web. Seven patients with JIA and CA required primary stoma, while rest were managed by excision of dilated proximal segment and primary anastomosis. Complications included anastomotic leak in 5, proximal perforation in 2, functional obstruction in 7, aspiration pneumonitis in 3, and wound infection in 6 patients. Mean hospital stay for survivors was 11 days. Overall survival was 63%. Conclusion: Late presentation, overcrowding in intensive care unit, septicemia, functional obstruction and anastomotic leak are the causes of poor outcome in our series. Early diagnosis, some modification in surgical technique, use of total parenteral nutrition and adequate investigations for other congenital anomalies may improve the outcome.

A unique PE_PGRS protein inhibiting host cell cytosolic defenses and sustaining full virulence of Mycobacterium marinum in multiple hosts.

Despite intense research, PE_PGRS proteins still represent an intriguing aspect of mycobacterial pathogenesis. These cell surface proteins influence virulence in several pathogenic species, but their diverse and exact functions remain unclear. Herein, we focussed on a PE_PGRS member from Mycobacterium marinum, MMAR_0242, characterized by an extended and unique C-terminal domain. We demonstrate that an M. marinum mutant carrying a transposon insertion in MMAR_0242 is highly impaired in its ability to replicate in macrophages and amoebae, because of its inability to inhibit lysosomal fusion. As a consequence, this mutant failed to survive intracellularly as evidenced by a reduced number of cytosolic actin tail-forming bacteria and by quantitative electron microscopy, which mainly localized MMAR_0242::Tn within membrane-defined vacuoles. Functional complementation studies indicated that the C-terminus, but not the N-terminal PE_PGRS domain, is required for intracellular growth/survival. In line with these findings, disruption of MMAR_0242 resulted in a highly attenuated virulence phenotype in zebrafish embryos, characterized by restricted bacterial loads and a failure to produce granulomas. Furthermore, expression of MMAR_0242 in Mycobacterium smegmatis, a non-pathogenic species naturally deficient in PE_PGRS production, resulted in increased survival in amoebae with enhanced cytotoxic cell death and increased survival in infected mice with splenomegaly. Overall, these results indicate that MMAR_0242 is required for full virulence of M. marinum and sufficient to confer pathogenic properties to M. smegmatis.

Stable Tricyclic Antitubercular Ozonides Derived from Artemisinin.

New, highly stable tricyclic antitubercular ozonides 9 and 10 derived from artemisinin are reported in 39 and 9% yields, respectively. The ozonide groups of 9 and 10 were found to be stable under strong basic and acidic conditions. The absolute configuration of ozonides 9 was confirmed by X-ray crystallography. Ozonide 10 shows promising antitubercular activity against M. tuberculosis H37Ra and M. tuberculosis H37Rv with MIC values of 0.39 and 3.12 µg/mL, respectively.

Thiophene containing trisubstituted methanes [TRSMs] as identified lead against Mycobacterium tuberculosis.

Triarylmethanes (TRAMs) and thiophene containing trisubstituted methanes (TRSMs) have been reported by us, having potential against Mycobacterium tuberculosis and Mycobacterium fortuitum strains, respectively. Further, extension through synthesis and biological evaluation of novel TRSMs resulted into an identified lead 36 (S006-830) [(diisopropyl-(2-{4-[(4-methoxy-phenyl)- thiophen-2-yl-methyl]-phenoxy}-ethyl)-amine)] with MIC: 1.33 mg/L, non-toxic against Vero C-1008 cell line with selectivity index >10, ex vivo efficacy equivalent to first line TB drugs-isoniazid (INH), rifampicin (RFM) and pyrazinamide (PZA) in the mouse and human macrophages, and lung CFU count of 2.2 × 10(7) (approximately 15 fold lesser than untreated mice, 31 × 10(7)) with efficacies comparable to ethambutol (EMB) (1.27 × 10(7)) and PZA (1.9 × 10(7)). Further, S006-830 also showed potent bactericidal activity against multi-drug resistant and single-drug resistant clinical isolates of M. tuberculosis.

Anti-tubercular agents from Glycyrrhiza glabra.

Bioactivity guided isolation of Glycyrrhiza glabra (Leguminosae / Fabaceae) roots resulted in the characterization of 18ß-glycyrrhetinic acid as a major anti-tubercular agent. Further, GA-1 was semi-synthetically converted into its nine derivatives, which were in-vitro evaluated for their antitubercular potential against Mycobacterium tuberculosis H37Rv using BACTEC-460 radiometric susceptibility assay. All the derivatives were active, but the benzylamide (GA-8, MIC 12.5µg/ml) and ethyl oxylate (GA-3, MIC 25.0 µg/ml) derivatives were significantly active against the pathogen. This was further supported by the molecular docking studies, which showed adequate docking (LibDock) scores for GA-3 (120.3) and GA-8 (112.6) with respect to the standard anti-tubercular drug, rifampicin (92.94) on the DNA-directed RNA polymerase subunit beta (rpoB) target site. Finally, the in silico pharmacokinetic and drug-likeness studies showed that GA-3 and GA- 8 possesses drug-like properties. This is the first ever report on the anti-tubercular potential of GA and its derivatives. These results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non toxic natural product.

Phytochemical screening of five medicinal legumes and their evaluation for in vitro anti-tubercular activity.

BACKGROUND: Tuberculosis is a leading cause of death in the world. A new alternative for the treatment of tuberculosis is urgently required, due to the emergence of multidrug resistant Mycobacterium tuberculosis. AIM: There is currently considerable interest in developing potential drugs from medicinal plants for treating tuberculosis. To evaluate anti-tubercular activity in the leaves of Kingiodendron pinnatum Rox. Hams., Humboldtia brunonis Wall., Indigofera cassioides Rottl.ex DC., Derris scandens Benth. and Ceasalpinia mimosoides Lamk. MATERIALS AND METHODS: Non-polar and polar solvent extracts of leaves of these medicinal legumes were tested against M. tuberculosis H37RV and minimum inhibitory concentrations (MICs) were determined by the agar based proportion assay. RESULTS: Phytochemical screening for secondary metabolites revealed the presence of saponins, steroids, anthro-quinones, terpinods, flavonoids and phlabotanins. Crude leaf extracts of these plants have shown MIC value of 50 µg/ml as against the standard drug Isoniazid value of 0.025 µg/ml. CONCLUSION: Results showed that crude extracts of legume leaves screened exhibited potential anti-tubercular activity against M. tuberculosis and further work is required to identify the active molecule of these legumes, to get a novel anti-tubercular drug. This is the maiden finding on anti-tubercular activity of these medicinal legumes.