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1.
ACS Infect Dis ; 2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32330004

RESUMO

Twenty-three polymyxin analogs with variations at nine amino acid positions were synthesized and assessed for antimicrobial activity and renal cytotoxicity. Compounds M2, 14, S2, and 16 (MIC = 0.125-4 µg/mL) had similar or stronger activities against susceptible and drug-resistant strains of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii compared to polymyxin B (MIC = 1-2 µg/mL). Most synthesized compounds (50% cytotoxic concentration, CC50 ≥ 200 µg/mL) exhibited lower cytotoxicity than polymyxin B (CC50 = 99 ± 6 µg/mL). Polymyxin S2 showed high plasma stability in vitro and strong efficacy in a mouse systemic infection model (ED50 = 0.9 mg/kg) against NDM-1-producing Klebsiella pneumoniae, suggesting that it is a potential candidate for drug development. The activity and cytotoxicity results indicated that the amino acids at positions 2, 3, 6, and 7 might be replaced. Effects on activity and cytotoxicity linked to changes in the number of positively charged amino acids varied among different cyclopeptide skeletons, but the underlying mechanisms are unknown.

2.
Bioorg Med Chem Lett ; 30(7): 126969, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32014384

RESUMO

In this work, according to the 'me-too me-better' design strategy, a peculiar side chain different from lefamulin at C14 position of pleuromutilin was introduced. A series of novel thioether pleuromutilin derivatives containing cyclohexane in the C14 chain was synthesized by ten-step synthesis reaction. All derivatives were characterized by Nuclear Magnetic Resonance (NMR) and High Resolution Mass Spectrometer (HRMS). Furthermore, majority of derivatives displayed moderate antibacterial activity in vitro. However, the compound 2C and 2J exhibited comparable or superior antibacterial activity to lefamulin. The summarized structure-activity relationship not only made the variety of pleuromutilin derivatives more diverse, but also provided new ideas for its design and development.

3.
PLoS One ; 15(2): e0228797, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074133

RESUMO

(E)-N,N-dimethyl-4-oxo-4-(4-(pyridin-4-yl)phenyl)but-2-enamide hydrochloride (IMB-YH-4py5-2H) is a novel Protein Kinase B (PknB) inhibitor with potent activity against Mycobacterium tuberculosis strains. In the present study, a sensitive and specific liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine IMB-YH-4py5-2H in rat plasma. Sample pretreatment was achieved by liquid-liquid extraction with ethyl acetate, and separation was performed on an XTerra MS C18 column (2.1×50 mm, 3.5 µm) with gradient elution (methanol and 0.1% formic acid) at a flow rate of 0.3 mL/min. Detection was performed in multiple reaction monitoring (MRM) mode. Linear calibration curves were obtained over a concentration range of 1-100 ng/mL. The intra-day and inter-day precisions were lower than 8.46%, and the accuracies ranged from -8.71% to 12.36% at all quality control levels. The extraction recoveries were approximately 70%, and the matrix effects were negligible. All quality control samples were stable under different storage conditions. The validated method was successfully applied to a preclinical pharmacokinetic study in Sprague-Dawley rats. IMB-YH-4py5-2H demonstrated improved pharmacokinetic properties (higher exposure level) compared with its leading compound. IMB-YH-4py5-2H was also distributed throughout the lung pronouncedly, especially inside alveolar macrophages, indicating its effectiveness against lower respiratory infections.


Assuntos
Análise Química do Sangue/métodos , Cromatografia Líquida/métodos , Limite de Detecção , Piridinas/sangue , Piridinas/farmacocinética , Espectrometria de Massas em Tandem/métodos , Animais , Antituberculosos/sangue , Antituberculosos/isolamento & purificação , Antituberculosos/farmacocinética , Piridinas/isolamento & purificação , Ratos , Ratos Sprague-Dawley
4.
Bioorg Chem ; 94: 103487, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31831161

RESUMO

Based on the structural characteristics of aztreonam (AZN) and its target PBP3, a series of new monobactam derivatives bearing various substituents on oxime residue were prepared and evaluated for their antibacterial activities against susceptible and resistant Gram-negative bacteria. Among them, compounds 8p and 8r displayed moderate potency with MIC values of 0.125-32 µg/mL against most tested Gram-negative strains, comparable to AZN. Meanwhile, the combination of 8p and 8r with avibactam as a ß-lactamases inhibitor, in a ratio of 1:16, showed a promising synergistic effect against both ESBLs- and NDM-1-producing K. pneumoniae, with significantly reduced MIC values up to 8-fold and >256-fold respectively. Furthermore, both of them demonstrated excellent safety profiles both in vitro and in vivo. The results provided powerful information for further structural optimization of monobactam antibiotics to fight ß-lactamase-producing resistant Gram-negative bacteria.

5.
PLoS One ; 14(6): e0217573, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31170198

RESUMO

Pharmacological efficacy is based on the drug concentration in target tissues, which usually cannot be represented by the plasma concentration. The purpose of this study was to compare the pharmacokinetic characteristics of gemifloxacin in plasma and skeletal muscle and evaluate its tissue penetration in both healthy and MRSA (methicillin-resistant Staphylococcus aureus)-infected rats. A microdialysis (MD) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine free gemifloxacin concentrations in rat plasma and skeletal muscle simultaneously. The in vivo recoveries of MD were 23.21% ± 3.42% for skeletal muscle and 20.62% ± 3.19% for plasma, and were concentration independent. We provided evidence that the method developed here meets FDA requirements. Additionally, this method was successfully applied to the determination of free gemifloxacin in rats. Muscle and blood dialysates were collected after an 18 mg/kg intravenous bolus dose. The mean areas under the concentration-time curves (AUCs) from 0 to 9 h for skeletal muscle and plasma were 3641.50 ± 915.65 h*ng/mL and 7068.32 ± 1964.19 h*ng/mL in MRSA-infected rats and 3774.72 ± 700.36 h*ng/mL and 6927.49 ± 1714.86 h*ng/mL in healthy rats, respectively. There was no significant difference (P>0.05) in gemifloxacin exposure between healthy rats and MRSA-infected rats for plasma or muscle. The low ratio of AUC0-9 muscle to AUC0-9 plasma suggested lower drug exposure in skeletal muscle than in plasma for both healthy and MRSA-infected rats. Our study suggested that the administration of gemifloxacin according to drug levels in plasma to treat local infection is unreasonable and might result in an inadequate dose regimen.


Assuntos
Gemifloxacina/análise , Gemifloxacina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Microdiálise , Músculos/efeitos dos fármacos , Músculos/microbiologia , Espectrometria de Massas em Tandem , Animais , Proteínas Sanguíneas/metabolismo , Cromatografia Líquida , Ciprofloxacino/química , Ciprofloxacino/farmacologia , Modelos Animais de Doenças , Gemifloxacina/química , Gemifloxacina/farmacocinética , Masculino , Ligação Proteica , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Coxa da Perna/microbiologia , Distribuição Tecidual
6.
Molecules ; 24(5)2019 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-30862066

RESUMO

Twenty-five new derivatives of 8-hydroxycycloberberine (1) were synthesized and evaluated for their activities against Gram-positive bacteria, taking 1 as the lead. Part of them displayed satisfactory antibacterial activities against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA), as well as vancomycin-intermediate Staphylococcus aureus (VISA). Especially, compound 15a displayed an excellent anti-MRSA activity with MICs (minimum inhibitory concentrations) of 0.25⁻0.5 µg/mL, better than that of 1. It also displayed high stability in liver microsomes and whole blood, and the LD50 value of over 65.6 mg·kg-1 in mice via intravenous route, suggesting a good druglike feature. The mode of action showed that 15a could effectively suppress topo IV-mediated decatenation activity at the concentration of 7.5 µg/mL, through binding a different active pocket of bacterial topo IV from quinolones. Taken together, the derivatives of 1 constituted a promising kind of anti-MRSA agents with a unique chemical scaffold and a specific biological mechanism, and compound 15a has been chosen for the next investigation.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Berberina/química , Berberina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Berberina/análogos & derivados , DNA Topoisomerase IV/antagonistas & inibidores , DNA Topoisomerase IV/química , Relação Dose-Resposta a Droga , Estabilidade de Medicamentos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Relação Estrutura-Atividade
7.
Eur J Med Chem ; 168: 283-292, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30825723

RESUMO

A series of new 7-substituted cycloberberine (CBBR) derivatives were synthesized and evaluated for their antibacterial activities against Gram-positive pathogens, taking CBBR as the lead. The SAR revealed that the introduction of a substituent at the C7 position resulted in a potency against both the reference Gram-positive bacteria and MDR clinical isolates, much higher than that of CBBR. Compound 1f with a 7-phenyl group exhibited higher activities against MRSA and VRE than that of vancomycin, with MIC values of 1-8 µg/mL. Its rapid bactericidal action against MRSA was further confirmed in time-kill study. The preliminary mechanism study indicated that 1f might target bacterial DNA Topo IV ParE subunit, indicating a mode of action distinct from the currently used antibacterial drugs such as quinolones. These results supplemented and enriched the SAR of its kind, and provided powerful information for developing these compounds into a novel class of antibacterial candidates against MRSA.


Assuntos
Antibacterianos/farmacologia , Berberina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Berberina/análogos & derivados , Berberina/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
8.
Molecules ; 24(3)2019 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-30717338

RESUMO

Nineteen new quinoline derivatives were prepared via the Mannich reaction and evaluated for their antibacterial activities against both Gram-positive (G⁺) and Gram-negative (G-) bacteria, taking compound 1 as the lead. Among the target compounds, quinolone coupled hybrid 5d exerted the potential effect against most of the tested G⁺ and G- strains with MIC values of 0.125⁻8 µg/mL, much better than those of 1. Molecular-docking assay showed that compound 5d might target both bacterial LptA and Top IV proteins, thereby displaying a broad-spectrum antibacterial effect. This hybridization strategy was an efficient way to promote the antibacterial activity of this kind, and compound 5d was selected for the further investigation, with an advantage of a dual-target mechanism of action.


Assuntos
Antibacterianos/química , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Quinolinas/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Proteínas de Transporte/química , Proteínas de Escherichia coli/química , Bactérias Gram-Negativas/patogenicidade , Bactérias Gram-Positivas/patogenicidade , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Quinolinas/síntese química , Quinolinas/farmacologia , Relação Estrutura-Atividade
9.
Org Lett ; 21(6): 1583-1587, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30799624

RESUMO

A pair of enantiomeric triketone-phloroglucinol hybrids, (+)- and (-)-myrtuspirone A (1), featuring an unprecedented 3-isopropyl-3 H-spiro[benzofuran-2,1'-cyclohexane] backbone, were isolated from the leaves of Myrtus communis. The absolute configuration of each enantiomer of 1 was determined by X-ray diffraction and chemical calculations. Furthermore, the gram-scale total syntheses of (±)-1 and (-)-1 were conducted in four steps using a Michael- N-iodosuccinimide (NIS)-mediated (3 + 2)-annulation reaction. Both (+)- and (-)-1 exhibited antibacterial activities against Gram-positive bacteria including multidrug-resistant strains.


Assuntos
Antibacterianos , Benzofuranos , Cicloexanos/química , Bactérias Gram-Positivas/efeitos dos fármacos , Myrtus/química , Folhas de Planta/química , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Benzofuranos/síntese química , Benzofuranos/química , Benzofuranos/farmacologia , Estrutura Molecular , Floroglucinol/química , Estereoisomerismo
10.
Bioorg Med Chem Lett ; 29(4): 539-543, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30630715

RESUMO

A series of novel (E)-4-oxo-2-crotonamide derivatives were designed and synthesized to find potent antituberculosis agents. All the target compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv(MTB). Results reveal that 4-phenyl moiety at part A and short methyl group at part C were found to be favorable. Most of the derivatives displayed promising activity against MTB with MIC ranging from 0.125 to 4 µg/mL. Especially, compound IIIa16 was found to have the best activity with MIC of 0.125 µg/mL against MTB and with MIC in the range of 0.05-0.48 µg/mL against drug-resistant clinical MTB isolates.

11.
Chem Biodivers ; 16(2): e1800560, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30467968

RESUMO

A series of novel thioether or sulfoxide-type pleuromutilin derivatives containing heteroaromatic substituents at the end of C14 side chain were designed and synthesized. All of the derivatives were evaluated for their in vitro antibacterial activity. Some of them showed good to excellent antibacterial activity comparable to retapamulin and azamulin in most of the tested Gram-positive pathogens. In this work, a five-membered heterocyclic moiety, a pyrimidine-heterocyclic moiety, or a benzoheterocyclic moiety was introduced in the C14 side chain to increase the structural diversity of the pleuromutilin derivatives. The antibacterial results reveal that the thioether-containing pleuromutilin derivatives exert a more potency activity than the sulfoxide-type derivatives against Gram-positive pathogens. The structure-activity relationship summarized in this work may provide with some interesting clues as to which functionalities are beneficial for high antimicrobial activity of the pleuromutilin derivatives.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Diterpenos/química , Diterpenos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Compostos Policíclicos , Relação Estrutura-Atividade , Sulfetos , Sulfóxidos
12.
Int J Antimicrob Agents ; 52(6): 799-804, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30194973

RESUMO

Transfer of aac(6')-aph(2″) transposons mediating high-level gentamicin resistance (HLGR) in Enterococcus faecalis is a serious problem in the clinic. However, factors affecting the transfer of aac(6')-aph(2″) have not yet been elucidated. The current study aimed to examine the genetic and molecular basis of HLGR in E. faecalis strains isolated in Beijing (China) and to clarify the relationship between transfer efficiency of aac(6')-aph(2″) transposons and the transposon structure/location. A total of five transposon structures were identified by PCR mapping of the corresponding transposon regions, including a Tn5281-like non-truncated transposon and four truncated transposons. A plasmid location study of aac(6')-aph(2″) by Southern blot following S1-PFGE and filter mating conjugation experiments demonstrated that plasmid location rates correlated with conjugation-positive rates. Chromosome walking to identify the sequence upstream of a representative type III truncated transposon found a truncated aph(2″)-Ia region, and further PCR analysis of this region among strains from different groups revealed similar a positive rate trend as the transposon plasmid location rate and conjugation-positive rate. In conclusion, aac(6')-aph(2″) transposons were of different structures in E. faecalis strains from Beijing, with two new transposon structures that have not been reported elsewhere. Presence of the truncated aph(2″)-Ia region upstream of some truncated transposons suggests recombination between aminoglycoside-modifying enzyme genes. Possible links exist among plasmid location, conjugation and the presence of truncated aph(2″)-Ia upstream of the transposon.


Assuntos
Acetiltransferases/genética , Elementos de DNA Transponíveis , Farmacorresistência Bacteriana , Enterococcus faecalis/genética , Transferência Genética Horizontal , Infecções por Bactérias Gram-Positivas/microbiologia , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Antibacterianos/farmacologia , Pequim , Mapeamento Cromossômico , Conjugação Genética , Enterococcus faecalis/classificação , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/isolamento & purificação , Variação Genética , Gentamicinas/farmacologia , Humanos , Plasmídeos/análise , Reação em Cadeia da Polimerase
13.
Eur J Med Chem ; 157: 877-886, 2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30145374

RESUMO

A series of new 13-substituted cycloberberine (CBBR) derivatives were prepared and evaluated for their antibacterial activities against Gram-positive bacteria taking CBBR as the lead. Structure-activity relationship revealed that the introduction of a suitable electron-donating group at the 13-position in CBBR might be beneficial for the antibacterial potency. Among them, compounds 5b and 5w exhibited high potency against methicillin-sensitive (MSSA) and resistant strains of S. aureus (MRSA) with MIC values of 1-4 µg/mL. Both of them also displayed high stabilities in blood, and good in vivo safety profiles with LD50 values of 65.6 and 41.2 mg kg-1 in intravenous route respectively. Molecular docking analysis indicated that compound 5b might target FtsZ protein that could inhibit cell division, with the advantage of activity against multidrug resistant S. aureus. Therefore, we consider 13-substituted CBBR derivatives to be a novel class of anti-MRSA agents worthy of further investigation.


Assuntos
Antibacterianos/farmacologia , Berberina/envenenamento , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Berberina/síntese química , Berberina/química , Relação Dose-Resposta a Droga , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
14.
Chem Sci ; 9(6): 1488-1495, 2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29629171

RESUMO

Herein, we describe a concise catalytic approach to the first asymmetric total syntheses of myrtucommuacetalone, myrtucommuacetalone B, and callistrilones A, C, D and E. The syntheses proceed in only 5-7 steps from the readily available compound 11, without the need for protecting groups. Key features of the syntheses include a unique organocatalytic asymmetric Friedel-Crafts-type Michael addition with high enantioselectivity and a broad substrate scope, a novel Michael-ketalization-annulation cascade reaction, and an oxidative [3 + 2] cycloaddition. Furthermore, the new compound 7 exhibited potent antibacterial activities against several multidrug-resistant strains (MRSA, VISA and VRE), and showed greater potency than vancomycin.

15.
J Med Chem ; 61(5): 1845-1857, 2018 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-29412662

RESUMO

In this paper, 26 natural polymyxin components and a new derivative S2 were synthesized, and their differences in efficacy and toxicity have been investigated. Almost all of the synthesized components showed strong activity against both susceptible and resistant strains of E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii. The toxicities were obviously different between the components. Only some of the components were tested for toxicity in vivo. Compounds E2, E2-Val, A2, M2, D2, and S2 showed obviously lower renal cytotoxicity and acute toxicity than polymyxins B and E. The in vivo nephrotoxicity of E2, M2, and S2 was similar to that of polymyxin E. Compound S2, with four positive charges, was especially interesting as it possessed both increased efficacy and decreased toxicity. The SAR and toxicity studies indicated that further structural modification could concentrate on polymyxin S. The results also indicated that S2 could be a new drug candidate.


Assuntos
Bactérias/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Polimixinas/toxicidade , Animais , Humanos , Fígado/efeitos dos fármacos , Peptídeos Cíclicos/química , Polimixinas/análogos & derivados , Polimixinas/síntese química , Relação Estrutura-Atividade , Testes de Toxicidade
16.
Acta Pharmacol Sin ; 39(2): 213-221, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28748913

RESUMO

Cholestatic liver diseases are important causes of liver cirrhosis and liver transplantation, but few drugs are available for treatment. D-chiro-inositol (DCI), an isomer of inositol found in many Leguminosae plants and in animal viscera, is used clinically for the treatment of polycystic ovary syndrome (PCOS) and diabetes mellitus. In this study, we investigated whether DCI exerted an anti-cholestatic effect and its underlying mechanisms. A cholestatic rat model was established via bile duct ligation (BDL). After the surgery, the rats were given DCI (150 mg·kg-1·d-1) in drinking water for 2 weeks. Oral administration of DCI significantly decreased the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and attenuated bile duct proliferation, parenchymal necrosis and fibrosis in BDL rats. Furthermore, DCI treatment significantly increased the serum and bile levels of total bile acid (TBA), and decreased TBA levels in the liver. Moreover, DCI treatment significantly increased expression of the genes encoding bile acid transporters BSEP (Abcb11) and MRP2 (Abcc2) in liver tissues. DCI treatment also markedly decreased hepatic CD68 and NF-kappaB (NF-κB) levels, significantly decreased the serum and hepatic MDA levels, markedly increased superoxide dismutase activity in both serum and liver tissues. Using whole-genome oligonucleotide microarray, we revealed that DCI treatment altered the expression profiles of oxidation reduction-related genes in liver tissues. Collectively, DCI effectively attenuates BDL-induced hepatic bile acid accumulation and decreases the severity of injury and fibrosis by improving bile acid secretion, repressing inflammation and decreasing oxidative stress. The results suggest that DCI might be beneficial for patients with cholestatic disorders.


Assuntos
Ácidos e Sais Biliares/metabolismo , Colestase/prevenção & controle , Inositol/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/uso terapêutico , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Alanina Transaminase/sangue , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Aspartato Aminotransferases/sangue , Ductos Biliares/cirurgia , Modelos Animais de Doenças , Expressão Gênica/efeitos dos fármacos , Inositol/administração & dosagem , Ligadura , Fígado/patologia , Cirrose Hepática/prevenção & controle , Masculino , NF-kappa B/metabolismo , Substâncias Protetoras/administração & dosagem , Ratos Sprague-Dawley , Estereoisomerismo , Superóxido Dismutase/metabolismo
17.
Appl Microbiol Biotechnol ; 101(19): 7201-7212, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28812125

RESUMO

Ferredoxins are iron-sulfur protein that mediate electron transfer in cytochrome P450 mono-oxygenase (CYP)-related catalytic reactions in a wide variety of organisms. Rv1786 is a putative ferredoxin, encoded by a gene located downstream of the gene encoding CYP143A1 in the Mycobacterium tuberculosis genome. However, the structure and function of Rv1786 have remained unclear. Here, the recombinant Mtb Rv1786 was expressed, purified as a His-tagged form and characterized with [3Fe-4S] clusters as its cofactors using a series of measurements including SDS-PAGE, western blot, UV/Visible, MALDI-TOF/TOF-MS, and electron paramagnetic resonance spectroscopic analysis. Based on the assessments of surface plasmon resonance (SPR) and steady state kinetic assays, Rv1786 was found to be able to couple with both ferredoxin reductase A (FdrA) and flavoprotein reductase A (FprA) as redox partner, but with a stronger binding to FprA and a better coupling activity to FdrA. Preliminary structural and biochemical characterization of Mtb Rv1786 as a redox partner is presented here.


Assuntos
Proteínas de Bactérias/metabolismo , Ferredoxinas/metabolismo , Mycobacterium tuberculosis/metabolismo , Proteínas Recombinantes/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Catálise , Clonagem Molecular , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Ferredoxinas/genética , Proteínas com Ferro-Enxofre/genética , Proteínas com Ferro-Enxofre/metabolismo , Mycobacterium tuberculosis/genética , Filogenia , Proteínas Recombinantes/genética , Alinhamento de Sequência , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
18.
Sci Rep ; 7(1): 5093, 2017 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-28698545

RESUMO

Protein kinase B (PknB) is one of the Mycobacterium tuberculosis serine/threonine protein kinases and has an essential role in sustaining mycobacterial growth. Here, we identified and characterized a novel small molecule compound named IMB-YH-8 that inhibited PknB and served as anti-mycobacteria lead compound. IMB-YH-8 inhibited PknB auto-phosphorylation and the phosphorylation of GarA by PknB in a dose-dependent manner. The compound did not inhibit human Akt1 or other serine/threonine kinases in M. tuberculosis except for the highly homologous PknA. IMB-YH-8 bound to PknB with a moderate affinity. Molecular docking revealed that IMB-YH-8 interacts with the catalytic domain of PknB. Observations of electron microscopy showed that IMB-YH-8 changed the morphology of H37Rv and disrupted the cell wall. The differential transcriptional response of M. tuberculosis to IMB-YH-8 revealed changes in SigH regulatory pathways modulated by PknB. Notably IMB-YH-8 not only potently inhibited drug-sensitive and multidrug-resistant clinical isolates but also exhibited a dose dependent inhibition of intracellular M. tuberculosis. Taken together, these in vitro data demonstrate that IMB-YH-8 is a novel inhibitor of PknB, which potently prevents growth of M. tuberculosis. It is as yet unclear whether inhibition of PknA contributes to the anti-tubercular action of IMB-YH-8.


Assuntos
Anisóis/uso terapêutico , Antituberculosos/uso terapêutico , Butiratos/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Tuberculose/tratamento farmacológico , Anisóis/química , Anisóis/farmacologia , Antituberculosos/química , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Butiratos/química , Butiratos/farmacologia , Domínio Catalítico , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Farmacorresistência Bacteriana/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/ultraestrutura , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/química , Proteínas Proto-Oncogênicas c-akt/metabolismo , Estereoisomerismo , Especificidade por Substrato/efeitos dos fármacos , Tuberculose/microbiologia
19.
Metabolism ; 70: 72-84, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28403947

RESUMO

OBJECTIVE: Berberine (BBR) clinically lowers blood lipid and glucose levels via multi-target mechanisms. One of the possible mechanisms is related to its effect on the short chain fatty acids (SCFAs) of the gut microbiota. The goal of this study is to investigate the therapeutic effect and mode of action of BBR working through SCFAs of the gut microbiota (especially, butyrate). METHODS: Gas chromatography (GC) was used to detect butyrate and other SCFAs chemically. The effect of BBR on butyrate production was investigated in vitro as well as in several animal systems. Microarrays were used to analyze the composition change in the intestinal bacteria community after treatment with BBR. BBR-induced change in the energy production and gene regulation of intestinal bacteria was examined in order to elucidate the underlying molecular mechanisms. RESULTS: We show that oral administration of BBR in animals promoted the gut microbiota to produce butyrate, which then enters the blood and reduces blood lipid and glucose levels. Incubating gut bacterial strains in vitro with BBR increased butyrate production. Orally treating animals directly with butyrate reduced blood lipid and glucose levels through a mechanism different from that of BBR. Intraperitoneal BBR administration did not increase butyrate but reduced blood lipid and glucose levels, suggesting that BBR has two modes of action: the direct effect of the circulated BBR and the indirect effect working through butyrate of the gut microbiota. Pre-treating animals orally with antibiotics abolished the effect of BBR on butyrate. A mechanism study showed that BBR (given orally) modified mice intestinal bacterial composition by increasing the abundance of butyrate-producing bacteria. Furthermore, BBR suppressed bacterial ATP production and NADH levels, resulting in increased butyryl-CoA and, eventually, butyrate production via upregulating phosphotransbutyrylase/butyrate kinase and butyryl-CoA:acetate-CoA transferase in bacteria. CONCLUSION: Promotion of butyrate (etc) production in gut microbiota might be one of the important mechanisms of BBR in regulating energy metabolism.


Assuntos
Berberina/farmacologia , Metabolismo Energético/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Berberina/administração & dosagem , Glicemia/efeitos dos fármacos , Butiratos/sangue , Butiratos/metabolismo , Cricetinae , Lipídeos/sangue , Masculino , Camundongos , Ratos
20.
Molecules ; 21(11)2016 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-27886094

RESUMO

Two new amicoumacins, named Damxungmacin A (1) and B (2), were isolated from the culture broth of a soil-derived bacterium Bacillus subtilis XZ-7. Their chemical structures were elucidated by spectroscopic studies (UV, IR, NMR and HR-ESI-MS). Compound 1 possessed a 1,4-diazabicyclo[2.2.1]heptane-2-one ring system in its structure, which was reported for the first time, while 2 had a 1-acetylmorpholine-3-one moiety, which was naturally rare. Compound 1 exhibited moderate to weak cytotoxic activities against three human tumor cell lines (A549, HCT116 and HepG2) with IC50 values of 13.33, 14.34 and 13.64 µM, respectively. Meanwhile, compound 1 showed weak antibacterial activities against some strains of Staphylococcus epidermidis, while compound 2 at 16 µg/mL did not show antibacterial activity.


Assuntos
Antineoplásicos/farmacologia , Bacillus subtilis/química , Cumarínicos/isolamento & purificação , Cumarínicos/farmacologia , Células A549 , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Bacillus subtilis/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cumarínicos/química , Células HCT116 , Células Hep G2 , Humanos , Estrutura Molecular , Microbiologia do Solo , Staphylococcus epidermidis/efeitos dos fármacos
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