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Ruoyan Ying,1,2 Xiaochen Huang,1 Yaxian Gao,1,3 Jie Wang,1 Yidian Liu,2 Wei Sha,2 Hua Yang1 1Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, People’s Republic of China; 2Tuberculosis Center for Diagnosis and Treatment, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200043, People’s Republic of China; 3School of Public Health, Guizhou Medical University, Guiyang, Guizhou Province, 550004, People’s Republic of ChinaCorrespondence: Hua YangShanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, People’s Republic of ChinaTel/Fax +86 21 65115006 ex 3037Email yanghua97065@tongji.edu.cnWei ShaTuberculosis Center for Diagnosis and Treatment, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200043, People’s Republic of ChinaTel/Fax +86 21 13671758200Email shfksw@126.comBackground: Retreatment tuberculosis (TB) has become a major source of drug-resistant TB. In contrast to the combination of isoniazid (INH) and rifampicin (RIF), that of pasiniazid (Pa) and rifabutin (RFB) or rifapentine (RFP) appears to have better activity in vitro against drug-resistant Mycobacterium tuberculosis (MTB), especially when combined with moxifloxacin (MXF). However, there has been limited study of potential synergism among Pa, RFB, RFP, and MXF, or simultaneous comparison with the standard INH and RIF combination.Methods: In vitro synergism of four two-drug combinations (INH and RIF, Pa and RFB, Pa and RFP, MXF and Pa) and two three-drug combinations (MXF and Pa combined with RFB or RFP) was evaluated against 90 drug-resistant MTB strains isolated from retreatment TB patients by the checkerboard method. The fractional inhibitory concentration index (FICI) was calculated for each combination.Results: The synergistic activity of the combination of Pa with RFB or RFP was higher than that of INH and RIF or MXF and Pa, and the synergistic activity of Pa in combination with RFP was even higher than that of RFB, although RFP yielded an MIC90 of 64 mg/liter, higher than that of RFB of 8 mg/liter against 90 drug-resistant MTB strains. Meanwhile, for three-drug combinations, the synergistic effects of MXF and Pa combined with RFB or RFP were similar. Further stratification analysis showed that, for XDR-MTB strains, the synergistic effect of the Pa and RFP combination was also better than those of other two-drug combinations.Conclusion: The combination of Pa with RFP shows better in vitro synergism than Pa with RFB and standard INH with RIF combinations, which can provide a reference for new regimens for retreatment TB patients.Keywords: Retreatment tuberculosis, XDR-MTB, MDR-MTB, Combined drug sensitivity, FICI, MIC

Post-replicative DNA methylation is essential for diverse biological processes in both eukaryotes and prokaryotes. Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, remains one of the most formidable threats worldwide. Although DNA methylation of M. tuberculosis has been documented, little information is available for clinical drug-resistant M. tuberculosis. Single-molecule real-time (SMRT) sequencing was used to profile the core methylome of three clinical isolates, namely multidrug-resistant (MDR), extensively drug-resistant (XDR) and extremely drug-resistant (XXDR) strains. 3812, 6808 and 6041 DNA methylated sites were identified in MDR-MTB, XDR-MTB and XXDR-MTB genome, respectively. There are two types of methylated motifs, namely N6-methyladenine (m6A) and N4-methylcytosine (m4C). A novel widespread 6 mA methylation motif 5′-CACGCAG-3′ was found in XDR-MTB and XXDR-MTB. The methylated genes are involved in multiple cellular processes, especially metabolic enzymes engaged in glucose metabolism, fatty acid and TCA cycle. Many methylated genes are involved in mycobacterial virulence, antibiotic resistance and tolerance. This provided a comprehensive list of methylated genes in drug-resistant clinical isolates and the basis for further functional elucidation. [ABSTRACT FROM AUTHOR]

The purpose of the studies was to evaluate an in-vitro anti-mycobacterial activity of Aloe vera and Allium sativum against MDR-MTB, their cytotoxicity and mutagenicity. Four extracts of Aloe vera and Allium sativum were prepared by Soxhlet apparatus and their minimum inhibitory concentrations (MIC's) were determined by BACTEC MGIT960 system against multi drug resistant Mycobacterium tuberculosis (MDR-MTB) isolates, collected from pediatric patients. Fractions of Aloe vera and Allium sativum extracts were separated using glass column chromatography, followed by evaluation of cytotoxicity and mutagenicity by tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Ames test, respectively. Out of four extracts, ethanol extracts of Aloe vera and Allium sativum exhibited activity at MIC 5mg/mL to 7mg/mL and 3mg/mL to 5mg/mL, respectively and IC50 by MTT assay for combination of all fractions were 278.3mcg/100μL and 270.8mcg/100μL and in Ames assay M.I of TA98 were 0.14 and 0.07 and M.I of TA100 were 1.14 and 0.44, respectively. Aloe vera and Allium sativum extracts showed anti-mycobacterial activity against MDR-MTB isolates so, MIC of ethanol extracts of each plant and fractions of column chromatography had been checked. The MTT and Ames tests depicted that ethanol extracts of Aloe vera and Allium sativum were non-cytotoxic and non-mutagenic, and can be used in treatment of patients suffering from MDRMTB. [ABSTRACT FROM AUTHOR]

A series of ethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-3-carboxylates 4a–f and dimethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylates 4g–k have been synthesized and evaluated for their anti-tubercular (TB) activities against H37Rv (American Type Culture Collection (ATCC) strain 25177) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis by resazurin microplate assay (REMA). Molecular target identification for these compounds was also carried out by a computational approach. All test compounds exhibited anti-tuberculosis (TB) activity in the range of 8–128 µg/mL against H37Rv. The test compound dimethyl-1-(4-fluorobenzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylate 4j emerged as the most promising anti-TB agent against H37Rv and multidrug-resistant strains of Mycobacterium tuberculosis at 8 and 16 µg/mL, respectively. In silico evaluation of pharmacokinetic properties indicated overall drug-likeness for most of the compounds. Docking studies were also carried out to investigate the binding affinities as well as interactions of these compounds with the target proteins.

We report herein the design, synthesis and antimycobacterial activity of 3,5-dinitrobenzamide derivatives containing fused ring moieties. Results reveal that many of the target compounds have considerable in vitro antitubercular activity. Especially, N -((2-(4-fluorophenyl)/ N -((2-(3-fluorobenzyl)-1,2,3,4-tetrahydroisoquilin-6-yl)methyl)-3,5-dinitrobenzamides 18a and 20e exhibit potent MIC values of 0.056–0.078 μg/mL against both drug-sensitive Mycobacterium tuberculosis (MTB) H37Rv strain and two clinically isolated multidrug-resistant MTB (MDR-MTB) strains, opening a new direction for further SAR studies. [ABSTRACT FROM AUTHOR]

A high-throughput screening effort on 45,000 compounds resulted in the discovery of a disubstituted oxazole as a new structural class inhibitor of Mycobacterium tuberculosis (Mtb). In order to improve the activity and investigate the SAR of this scaffold, a series of disubstituted azole analogues have been designed and synthesized. The newly synthesized compounds 1a – y were evaluated for their in vitro anti-TB activity versus replicating, multi- and extensive drug resistant Mtb strains. All the compounds, except 1o , 1p and 1q , showed potent anti-TB activity with MIC of 1–64 mg/L. The test of broad spectrum panel revealed that this series are specific to Mtb. The cytotoxicity assessment indicated that the compounds were not cytotoxic against HEK 293 cells. The compounds could have a novel mechanism to anti-Mtb as they can inhibit drug sensitive and drug resistant Mtb. [ABSTRACT FROM AUTHOR]

N -(5-Chlorobenzo[d]oxazol-2-yl)-4-methyl-1,2,3-thiadiazole-5-carboxamideox-amide has been identified as a potent inhibitor of Mtb H37Rv, with a minimum inhibitory concentration (MIC) of 0.42 μM. In this study, a series of substituted 2-acylamide-1,3-zole analogues were designed and synthesized, and their anti-Mtb activities were analyzed. In total, 17 compounds were found to be potent anti-Mtb agents, especially against the MDR- and XDR-MTB strains, with MIC values < 10 μM. These analogues can inhibit both drug-sensitive and drug-resistant Mtb. Four representative compounds were selected for further profiling, and the results indicate that compound 18 is acceptably safe and has favorable pharmacokinetic (PK) properties. In addition, this compound displays potent activity against Gram-positive bacteria, with MIC values in the range of 1.48–11.86 μM. The data obtained herein suggest that promising anti-Mtb candidates may be developed via structural modification, and that further research is needed to explore other compounds. Image 1 • Twenty-nine 2-acylamide-1,3-benzo[d]zole analogues were synthesized. • 17 compounds were found to be potent anti-Mtb agents, especially against the MDR and XDR-MTB strains, with MIC values<10 μM. • Compound 18 showed potent anti-Mtb activities, acceptably safe and favorable pharmacokinetic (PK) properties. • Compound 18 is also a potent anti-Gram-positive agent. [ABSTRACT FROM AUTHOR]

• Mycobacterium tuberculosis (MTB) infection has become a growing health risk. • Compound 1 and 2 displayed encouraging antimycobacterial activity with IC 50 of 3.2 µM and 1.5 µM against the H37Rv strain. • Compound 1 and 2 also displayed significant activity against five drug resistant isolates. Mycobacterium tuberculosis (MTB) infection has become a growing health risk as multi-drug resistant strain (MDR-MTB) has emerged worldwide. The development of isoniazid (INH)-resistant M. tuberculosis strains dictate the need to re-design this old drug to create effective analogs against the resistant INH strains. Synthesis and the biological activity of isoniazid and pyridine derivatives were successfully carried out with elaborated characterization by spectral data. Amongst the synthesized compounds; 1 and 2 displayed encouraging antimycobacterial activity with IC 50 of 3.2 µM and 1.5 µM against the H37Rv strain. The MIC of test compounds 1 and 2 were also assessed against the 5 drug resistant isolates (FQ-R1, INH-R1, INH-R2, RIF-R1 and RIF-R2) of MTB strains under aerobic conditions and compound 1 [MIC = 3.2 µM for FQ-R1; MIC = 140 µM for INH-R1; MIC = 160 µM for INH-R2; MIC = 2.4 µM towards RIF-R1; MIC = 4.2 µM for RIF-R2] and 2 [MIC = 3.3 µM for FQ-R1; MIC = 170 µM for INH-R1; MIC = 190 µM for INH-R2; MIC = 1.8 µM for RIF-R1; MIC = 8.4 µM for RIF-R2] have shown significant activity at non-cytotoxic concentration in comparison to the standard drug. [ABSTRACT FROM AUTHOR]

A series of ethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-3-carboxylates 4a–f and dimethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylates 4g–k have been synthesized and evaluated for their anti-tubercular (TB) activities against H37Rv (American Type Culture Collection (ATCC) strain 25177) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis by resazurin microplate assay (REMA). Molecular target identification for these compounds was also carried out by a computational approach. All test compounds exhibited anti-tuberculosis (TB) activity in the range of 8–128 µg/mL against H37Rv. The test compound dimethyl-1-(4-fluorobenzoyl)-5-methylpyrrolo[1,2-a]quinoline-2,3-dicarboxylate 4j emerged as the most promising anti-TB agent against H37Rv and multidrug-resistant strains of Mycobacterium tuberculosis at 8 and 16 µg/mL, respectively. In silico evaluation of pharmacokinetic properties indicated overall drug-likeness for most of the compounds. Docking studies were also carried out to investigate the binding affinities as well as interactions of these compounds with the target proteins. [ABSTRACT FROM AUTHOR]

A series of ethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2- a ]quinoline-3-carboxylates 4a - f and dimethyl 1-(substituted benzoyl)-5-methylpyrrolo[1,2- a ]quinoline-2,3-dicarboxylates 4g - k have been synthesized and evaluated for their anti-tubercular (TB) activities against H37Rv (American Type Culture Collection (ATCC) strain 25177) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis by resazurin microplate assay (REMA). Molecular target identification for these compounds was also carried out by a computational approach. All test compounds exhibited anti-tuberculosis (TB) activity in the range of 8-128 µg/mL against H37Rv. The test compound dimethyl-1-(4-fluorobenzoyl)-5-methylpyrrolo[1,2- a ]quinoline-2,3-dicarboxylate 4j emerged as the most promising anti-TB agent against H37Rv and multidrug-resistant strains of Mycobacterium tuberculosis at 8 and 16 µg/mL, respectively. In silico evaluation of pharmacokinetic properties indicated overall drug-likeness for most of the compounds. Docking studies were also carried out to investigate the binding affinities as well as interactions of these compounds with the target proteins.

Aim: Tuberculosis (TB) is one of the world's deadliest chronic infectious diseases caused mainly by Mycobacterium tuberculosis (MTB). Many nitrofuran derivatives were found to possess promising anti-TB potential and have been widely studied. In our previous study, we discovered diazaspiro-nitrofuran IMB1701-1702 as potent anti-TB agents., Methodology: We report herein a series of nitrofuranyl methyl N-heterocycles based on IMB1701-1702. Results reveal that most of them show potent activity (minimum inhibitory concentration: <0.016-0.062 μg/ml) against MTB H37Rv strain. Especially, compound 7h without cytotoxicity, has the same minimum inhibitory concentration value of ≤0.016 μg/ml as PBTZ169 against both MTB H37Rv strain and two clinically isolated multidrug-resistant MTB strains., Conclusion: The newly designed compound 7h might be a promising anti-TB candidate.

In vitro and ex vivo efficacies of four series of benzo[b]thiophene-2-carboxylic acid derivatives were studied against Mycobacterium tuberculosis H37Ra (MTB). Benzo[b]thiophenes were also tested in vitro against multidrug resistant Mycobacterium tuberculosis H37Ra (MDR-MTB), and 7b was found to be highly active against A- and D-MDR-MTB/MTB (MIC ranges 2.73-22.86 μg/mL). The activity of all benzo[b]thiophenes against M. bovis BCG (BCG) was also assessed grown under aerobic and under conditions of oxygen depletion. Compounds 8c and 8g showed significant activity with MICs of 0.60 and 0.61 μg/mL against dormant BCG. The low cytotoxicity and high selectivity index data against human cancer cell lines, HeLa, Panc-1, and THP-1 indicate the potential importance of the development of benzo[b]thiophene-based 1,3-diketones and flavones as lead candidates to treat mycobacterial infections. Molecular docking studies into the active site of DprE1 (Decaprenylphosphoryl-β-d-ribose-2'-epimerase) enzyme revealed a similar binding mode to native ligand in the crystal structure thereby helping to understand the ligand-protein interactions and establish a structural basis for inhibition of MTB. In summary, its good activity in in vitro and ex vivo model, as well as its activity against multidrug-resistant M. tuberculosis H37Ra in a potentially latent state, makes 7b an attractive drug candidate for the therapy of tuberculosis.