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1.
World J Microbiol Biotechnol ; 36(2): 24, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31965331

RESUMO

The study evaluated the antibacterial activity of chlorogenic acid (CA) against Salmonella Enteritidis S1, a foodborne pathogen in chilled fresh chicken. Its minimum inhibitory concentration for S. Enteritidis S1 was 2 mM. 1 MIC CA treatment reduced the viable count of S. Enteritidis S1 by 3 log cfu/g in chilled fresh chicken. Scanning electron microscopy examination indicated that CA induced the cell envelope damage of S. Enteritidis S1. Following this, 1-N-Phenylnaphthylamine assay and LPS content analysis indicated that CA induced the permeability of outer membrane (OM). Confocal laser scanning microscopy examination further demonstrated that CA acted on the inner membrane (IM). To support this, the release of intracellular protein and ATP after CA treatment was also observed. CA also suppressed the activities of malate dehydrogenase and succinate dehydrogenase, two main metabolic enzymes in TCA cycle and electron transport chain. Thus, damage of intracelluar and outer membranes as well as disruption of cell metabolism resulted in cell death eventually. The finding suggested that CA has the potential to be developed as a preservative to control S. Enteritidis associated foodborne diseases.


Assuntos
Antibacterianos/farmacologia , Ácido Clorogênico/farmacologia , Salmonella enteritidis/efeitos dos fármacos , Animais , Proteínas de Bactérias/antagonistas & inibidores , Membrana Celular/efeitos dos fármacos , Galinhas/microbiologia , Contagem de Colônia Microbiana , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Malato Desidrogenase/antagonistas & inibidores , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Salmonella enteritidis/enzimologia , Salmonella enteritidis/crescimento & desenvolvimento , Succinato Desidrogenase/antagonistas & inibidores
2.
J Enzyme Inhib Med Chem ; 35(1): 584-597, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31992093

RESUMO

NorA is the most studied efflux pump of Staphylococcus aureus and is responsible for high level resistance towards fluoroquinolone drugs. Although along the years many NorA efflux pump inhibitors (EPIs) have been reported, poor information is available about structure-activity relationship (SAR) around their nuclei and reliability of data supported by robust assays proving NorA inhibition. In this regard, we focussed efforts on the 2-phenylquinoline as a promising chemotype to develop potent NorA EPIs. Herein, we report SAR studies about the introduction of different aryl moieties on the quinoline C-2 position. The new derivative 37a showed an improved EPI activity (16-fold) with respect to the starting hit 1. Moreover, compound 37a exhibited a high potential in time-kill curves when combined with ciprofloxacin against SA-1199B (norA+). Also, 37a exhibited poor non-specific effect on bacterial membrane polarisation and showed an improvement in terms of "selectivity index" in comparison to 1.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Quinolinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Quinolinas/síntese química , Quinolinas/química , Staphylococcus aureus/metabolismo , Relação Estrutura-Atividade
3.
Eur J Med Chem ; 185: 111812, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31703818

RESUMO

Zinc metalloprotease 1 (Zmp1) is an extracellular enzyme, which has been found essential for the intracellular survival and pathogenesis of Mycobacterium tuberculosis. In this work, we designed and synthesized a series of novel thiazolidinedione-hydroxamates and evaluated in silico their drug-likeness behavior. Then, their inhibitory properties towards a recombinant Zmp1 from Mycobacterium tuberculosis were analyzed by MALDI-TOF MS. Nine of the tested compounds were found to inhibit the enzymatic reaction more effectively than the generic metalloprotease inhibitor phosphoramidon. Furthermore, the synthesized thiazolidinedione-hydroxamate hybrids were evaluated for their in vitro antimycobacterial activity and acute cytotoxicity using whole-cell assays. Results showed that none of the hybrids exhibited acute cytotoxicity against RAW264.7 macrophages. Whereas extracellular antimycobacterial activity was limited, RAW264.7 macrophage infection results showed that a majority of the hybrids inhibited the intracellular growth of Mycobacterium tuberculosis at a concentration of 100 and 10 µM. The thiazolidinedione-hydroxamate compound 2n was considered to be the best candidate of the evaluated library.


Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Ácidos Hidroxâmicos/farmacologia , Metaloproteases/antagonistas & inibidores , Mycobacterium tuberculosis/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Antituberculosos/síntese química , Antituberculosos/química , Proteínas de Bactérias/metabolismo , Relação Dose-Resposta a Droga , Humanos , Ácidos Hidroxâmicos/química , Metaloproteases/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/metabolismo , Relação Estrutura-Atividade , Tiazolidinedionas/química
4.
Pol J Microbiol ; 68(3): 331-341, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31880879

RESUMO

Streptococcus iniae is a pathogenic and zoonotic bacteria that impacted high mortality to many fish species as well as capable of causing serious disease to humans. Alanine racemase (Alr, EC 5.1.1.1) is a pyridoxal-5'-phosphate (PLP)-containing homodimeric enzyme that catalyzes the racemization of L-alanine and D-alanine. In this study, we purified alanine racemase from S. iniae that was isolated from an infected Chinese sturgeon (Acipenser sinensis), as well as determined its biochemical characteristics and inhibitors. The alr gene has an open reading frame (ORF) of 1107 bp, encoding a protein of 369 amino acids, which has a molecular mass of 40 kDa. The enzyme has optimal activity at a temperature of 35°C and a pH of 9.5. It belongs to the PLP-dependent enzymes family and is highly specific to L-alanine. S. iniae Alr (SiAlr) could be inhibited by some metal ions, hydroxylamine and dithiothreitol (DTT). The kinetic parameters K m and V max of the enzyme were 33.11 mM, 2426 units/mg for L-alanine, and 14.36 mM, 963.6 units/mg for D-alanine. Finally, the 50% inhibitory concentrations (IC50) values and antibiotic activity of two alanine racemase inhibitors (homogentisic acid and hydroquinone), were determined and found to be effective against both Gram-positive and Gram-negative bacteria employed in this study.Streptococcus iniae is a pathogenic and zoonotic bacteria that impacted high mortality to many fish species as well as capable of causing serious disease to humans. Alanine racemase (Alr, EC 5.1.1.1) is a pyridoxal-5'-phosphate (PLP)-containing homodimeric enzyme that catalyzes the racemization of L-alanine and D-alanine. In this study, we purified alanine racemase from S. iniae that was isolated from an infected Chinese sturgeon (Acipenser sinensis), as well as determined its biochemical characteristics and inhibitors. The alr gene has an open reading frame (ORF) of 1107 bp, encoding a protein of 369 amino acids, which has a molecular mass of 40 kDa. The enzyme has optimal activity at a temperature of 35°C and a pH of 9.5. It belongs to the PLP-dependent enzymes family and is highly specific to L-alanine. S. iniae Alr (SiAlr) could be inhibited by some metal ions, hydroxylamine and dithiothreitol (DTT). The kinetic parameters K m and V max of the enzyme were 33.11 mM, 2426 units/mg for L-alanine, and 14.36 mM, 963.6 units/mg for D-alanine. Finally, the 50% inhibitory concentrations (IC50) values and antibiotic activity of two alanine racemase inhibitors (homogentisic acid and hydroquinone), were determined and found to be effective against both Gram-positive and Gram-negative bacteria employed in this study.


Assuntos
Alanina Racemase/química , Alanina Racemase/isolamento & purificação , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Inibidores Enzimáticos/química , Infecções Estreptocócicas/microbiologia , Streptococcus iniae/enzimologia , Alanina Racemase/antagonistas & inibidores , Alanina Racemase/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Estabilidade Enzimática , Humanos , Cinética , Filogenia , Alinhamento de Sequência , Streptococcus iniae/química , Especificidade por Substrato
5.
Pol J Microbiol ; 68(4): 477-491, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880892

RESUMO

This study explored a potential treatment against methicillin-resistant Staphylococcus aureus (MRSA) infections that combines thioridazine (TZ), an efflux pump inhibitor, and miconazole (MCZ), an autolysis inducer, with the anti-microbial drug cloxacillin (CXN). In vitro, the combination treatment of TZ and MCZ significantly reduced 4096-fold (Σ (FIC) = 0.1 - 1.25) the MIC value of CXN against S. aureus. In vivo, the combination therapy significantly relieved breast redness and swelling in mice infected with either clinical or standard strains of S. aureus. Meanwhile, the number of bacteria isolated from the MRSA135-infected mice decreased significantly (p = 0.0427 < 0.05) after the combination therapy when compared to monotherapy. Moreover, the number of bacteria isolated from the mice infected with a reference S. aureus strain also decreased significantly (p = 0.0191 < 0.05) after the combination therapy when compared to monotherapy. The pathological changes were more significant in the CXN-treated group when compared to mice treated with a combination of three drugs. In addition, we found that combination therapy reduced the release of the bacteria-stimulated cytokines such as IL-6, IFN-γ, and TNF-α. Cytokine assays in serum revealed that CXN alone induced IL-6, IFN-γ, and TNF-α in the mouse groups infected with ATCC 29213 or MRSA135, and the combination of these three drugs significantly reduced IL-6, IFN-γ, and TNF-α concentrations. Also, the levels of TNF-α and IFN-γ in mice treated with a combination of three drugs were significantly lower than in the CXN-treated group. Given the synergistic antibacterial activity of CXN, we concluded that the combination of CXN with TZ, and MCZ could be developed as a novel therapeutic strategy against S. aureus.This study explored a potential treatment against methicillin-resistant Staphylococcus aureus (MRSA) infections that combines thioridazine (TZ), an efflux pump inhibitor, and miconazole (MCZ), an autolysis inducer, with the anti-microbial drug cloxacillin (CXN). In vitro, the combination treatment of TZ and MCZ significantly reduced 4096-fold (Σ (FIC) = 0.1 ­ 1.25) the MIC value of CXN against S. aureus. In vivo, the combination therapy significantly relieved breast redness and swelling in mice infected with either clinical or standard strains of S. aureus. Meanwhile, the number of bacteria isolated from the MRSA135-infected mice decreased significantly (p = 0.0427 < 0.05) after the combination therapy when compared to monotherapy. Moreover, the number of bacteria isolated from the mice infected with a reference S. aureus strain also decreased significantly (p = 0.0191 < 0.05) after the combination therapy when compared to monotherapy. The pathological changes were more significant in the CXN-treated group when compared to mice treated with a combination of three drugs. In addition, we found that combination therapy reduced the release of the bacteria-stimulated cytokines such as IL-6, IFN-γ, and TNF-α. Cytokine assays in serum revealed that CXN alone induced IL-6, IFN-γ, and TNF-α in the mouse groups infected with ATCC 29213 or MRSA135, and the combination of these three drugs significantly reduced IL-6, IFN-γ, and TNF-α concentrations. Also, the levels of TNF-α and IFN-γ in mice treated with a combination of three drugs were significantly lower than in the CXN-treated group. Given the synergistic antibacterial activity of CXN, we concluded that the combination of CXN with TZ, and MCZ could be developed as a novel therapeutic strategy against S. aureus.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Farmacorresistência Bacteriana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , beta-Lactamas/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacteriólise/efeitos dos fármacos , Cloxacilina/farmacologia , Quimioterapia Combinada , Humanos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Miconazol/farmacologia , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/citologia , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Tioridazina/farmacologia
6.
Chem Commun (Camb) ; 55(96): 14502-14505, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31730149

RESUMO

ForI is a PLP-dependent enzyme from the biosynthetic pathway of the C-nucleoside antibiotic formycin. Cycloserine is thought to inhibit PLP-dependent enzymes by irreversibly forming a PMP-isoxazole. We now report that ForI forms novel PMP-diketopiperazine derivatives following incubation with both d and l cycloserine. This unexpected result suggests chemical diversity in the chemistry of cycloserine inhibition.


Assuntos
Proteínas de Bactérias/metabolismo , Dicetopiperazinas/química , Formicinas/biossíntese , Fosfato de Piridoxal/química , Piridoxamina/análogos & derivados , Transaminases/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Biocatálise , Domínio Catalítico , Ciclosserina/química , Dicetopiperazinas/metabolismo , Formicinas/química , Concentração de Íons de Hidrogênio , Piridoxamina/química , Piridoxamina/metabolismo , Streptomyces/química , Streptomyces/metabolismo , Transaminases/antagonistas & inibidores , Transaminases/genética
7.
J Agric Food Chem ; 67(48): 13195-13211, 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31702908

RESUMO

The increase in the incidence of antibiotic-resistant Staphylococcus aureus (S. aureus) associated infections necessitates the urgent development of novel therapeutic strategies and antibacterial drugs. Antivirulence strategy is an especially compelling alternative strategy due to its low selective pressure for the development of drug resistance in bacteria. Plants and microorganisms are not only important food and medicinal resources but also serve as sources for the discovery of natural products that target bacterial virulence factors. This review discusses the mechanisms of the major virulence factors of S. aureus, including the accessory gene regulator quorum-sensing system, bacterial biofilm formation, α-hemolysin, sortase A, and staphyloxanthin. We also provide an overview of natural products isolated from plants and microorganisms with activity against the major virulence factors of S. aureus and their adjuvant effects on existing antibiotics to overcome antibiotic-resistant S. aureus. Finally, the limitations and solutions of these antivirulence compounds are discussed, which will help in the development of novel antibacterial drugs against antibiotic-resistant S. aureus.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Produtos Biológicos/farmacologia , Farmacorresistência Bacteriana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Fatores de Virulência/antagonistas & inibidores , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Humanos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
8.
Fitoterapia ; 139: 104371, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31629051

RESUMO

Extrusion of drugs or drug-like compounds through bacterial efflux pumps is a serious health issue that leads to loss in drug efficacy. Combinatorial therapies of low-efficacy drugs with efflux pump inhibitors may help to restore the activities of such drugs. In this quest, natural products are attractive molecules, since in addition to their wide range of bioactivities they may inhibit efflux pumps. The current work repurposed the bioactive alkaloid roemerine as a potential efflux pump inhibitor. In Bacillus subtilis, both Bmr and BmrA, belonging to the major facilitator and the ATP-binding cassette superfamilies, respectively, were found to be inhibited by roemerine. Scanning electron microscopy and RNA-Seq analyses showed that it potentiated the effect of berberine. Growth rates and checkerboard assays confirmed the synergy of roemerine and berberine and that roemerine prevented berberine efflux by inhibiting Bmr. Transport assays with inverted membrane vesicles prepared from Escherichia coli overexpressing BmrA showed that increasing roemerine concentration decreased the transport of doxorubicin, the BmrA substrate, confirming that roemerine may also be considered as an inhibitor of BmrA. Thus, these findings suggest that conjugation of roemerine to substrates of efflux pumps, Bmr and BmrA, may help to potentiate the activity of their drug substrates.


Assuntos
Antibacterianos/farmacologia , Aporfinas/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Alcaloides/farmacologia , Bacillus subtilis/efeitos dos fármacos , Berberina/farmacologia , Transporte Biológico , Reposicionamento de Medicamentos , Sinergismo Farmacológico , Escherichia coli/efeitos dos fármacos , Proteínas de Membrana Transportadoras , Testes de Sensibilidade Microbiana , Estrutura Molecular , Papaver/química , Componentes Aéreos da Planta/química , Turquia
9.
Comput Biol Chem ; 83: 107136, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31630014

RESUMO

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb). In the present age, due to the rapid increase in antibiotic resistance worldwide, TB has become a major threat to human life. Regardless of significant efforts have been inclined to improve the healthcare systems for improving diagnosis, treatment, and anticipatory measures controlling TB is challenging. To date, there are no such therapeutic chemical agents available to fight or control the bacterial drug-resistance. The catalase-peroxidase enzyme (katG) which encoded by the katG gene of Mtb is most frequently getting mutated and hence promotes Isoniazid resistance by diminishing the normal activity of katG enzyme. In the current study, an effort has been intended to find novel and therapeutically active antibacterial chemical compounds through pharmacoinformatics methodologies. Initially, the five mutant katG were generated by making mutation of Ser315 by Thr, Ile, Arg, Asn, and Gly followed by structural optimizations. About eight thousand small molecules were collected from the Asinex antibacterial library. All molecules were docked to active site of five mutant katG and wild type katG. To narrow down the chemical space several criteria were imposed including, screening for highest binding affinity towards katG proteins, compounds satisfying various criterion of drug-likeliness properties like Lipinski's rule of five (RO5), Veber's rule, absorption, distribution, metabolism, and excretion (ADME) profile, and synthetic accessibility. Finally, five molecules were found to be important antibacterial katG inhibitors. All the analyzed parameters suggested that selected molecules are promising in nature. Binding interactions analysis revealed that proposed molecules are efficient enough to form a number of strong binding interactions with katG proteins. Dynamic behavior of the proposed molecules with katG protein was evaluated through 100 ns molecular dynamics (MD) simulation study. Parameters calculated from the MD simulation trajectories adjudged that all molecules can form stable complexes with katG. High binding free energy of all proposed molecules definitely suggested strong affection towards the katG. Hence, it can be concluded that proposed molecules might be used as antibacterial chemical component subjected to experimental validation.


Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Peroxidases/antagonistas & inibidores , Antituberculosos/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Inibidores Enzimáticos/química , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Peroxidases/genética , Peroxidases/metabolismo
10.
J Agric Food Chem ; 67(43): 11867-11876, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31584805

RESUMO

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv oryzae (Xoo) is considered as the most destructive disease of rice. The use of bactericides is among the most widely used traditional methods to control this destructive disease. The excessive and repeated use of the same bactericides is also becoming the reason behind the development of bactericide resistance. The widely used method for finding the new antimicrobial agents often involves the bacterial virulence factors as a target without affecting bacterial growth. Type III secretion system (T3SS) is a protein appendage and is considered as having essential virulence factors in most Gram-negative bacteria. Due to the conserved construct, T3SS has been regarded as an important mark for the blooming of novel antimicrobial drugs. Toward the search of new T3SS inhibitors, an alternative series of 1,3-thiazole derivatives were designed and synthesized. Their structures were characterized and confirmed by 1H NMR, 13C NMR, MS, and elemental analysis. All the title compounds inhibited the promoter activity of hpa1 gene significantly. Eight of them showed better inhibition than our previous T3SS inhibitor TS006 (o-coumaric acid, OCA). The treatment of Xoo with eight compounds significantly attenuated HR without affecting bacterial growth. The mRNA levels of some representative genes (hrp/hrc genes) were reduced up to different extents. In vivo bioassay results showed that eight T3SS inhibitors could reduce bacterial leaf blight and bacterial leaf streak symptoms on rice, significantly.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Furanos/farmacologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Sistemas de Secreção Tipo III/antagonistas & inibidores , Xanthomonas/efeitos dos fármacos , Antibacterianos/síntese química , Antibacterianos/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Furanos/química , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Sistemas de Secreção Tipo III/genética , Sistemas de Secreção Tipo III/metabolismo , Xanthomonas/genética , Xanthomonas/metabolismo
11.
J Agric Food Chem ; 67(45): 12538-12546, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31638796

RESUMO

Cyanobacteria harmful algal blooms are of global concern, but all currently available algicides in the market are nonselective and have potential side effects on nontarget species. In the present work, two series of compounds (4 and 6) comprising 16 novel 1,2,3-triazole aminopyrimidines were rationally designed and synthesized as control agent for cyanobacteria. Our design focus was the inhibiting cyanobacteria by inhibition against pyruvate dehydrogenase complex E1 (PDHc-E1). Compounds 4 and 6 showed potent inhibition against Escherichia coli PDHc-E1 (IC50 = 4.13-23.76 µM) and also strong algicidal activities against Synechocystis sp. PCC 6803 (EC50 = 1.7-8.1 µM) and Microcystis sp. FACHB905 (EC50 = 2.1-11.8 µM). In particular, the algicidal activities of 6d against four algal species were not only higher than that of prometryn; they were also comparable to or higher than that of copper sulfate. The analogues 4c, 4d, 6d, and 6e displayed potent algicidal activities and inhibition of E. coli PDHc-E1 but exhibited negligible inhibition of porcine PDHc-E1. As revealed by molecular docking, site-directed mutagenesis, enzymatic assays, and an inhibition kinetic analysis, 4c and 6d inhibited PDHc-E1 in a competitive manner. Our results suggest that highly selective, effective algicides can be developed by rationally designing competitive PDHc-E1 inhibitors.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Herbicidas/farmacologia , Microcystis/efeitos dos fármacos , Pirimidinas/farmacologia , Piruvato Desidrogenase (Lipoamida)/antagonistas & inibidores , Synechocystis/efeitos dos fármacos , Triazóis/farmacologia , Proteínas de Bactérias/química , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Herbicidas/síntese química , Herbicidas/química , Cinética , Microcystis/química , Microcystis/enzimologia , Simulação de Acoplamento Molecular , Pirimidinas/química , Piruvato Desidrogenase (Lipoamida)/química , Relação Estrutura-Atividade , Synechocystis/química , Synechocystis/enzimologia , Triazóis/química
12.
Int J Mycobacteriol ; 8(3): 229-236, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31512598

RESUMO

Background: Leprosy is a neglected tropical disease affecting millions of people. The current treatment against leprosy includes various antibacterial drugs of which dapsone is known to bind to dihydropteroate synthase of Mycobacterium leprae. Dapsone is an expensive antibacterial drug with many side effects. A natural alternative for dapsone having less to no side effects and cheaper in production is needed. The three-dimensional protein structure of dihydropteroate synthase of M. leprae is not available. Methods: Protein homology modeling of target protein was carried out, and protein structure validation and energy minimization were performed. Phytochemicals mentioned in literature having anti-leprosy properties were studied for absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties and that which passed ADMET filters were further carried for comparative in silico docking analysis along with dapsone. Preliminary docking analysis was carried using AutoDock Vina, and results obtained were validated using AutoDock 4.2.6 and SwissDock. Results: Neobavaisoflavone was predicted to be ten times safer for administration than dapsone. On performing in silico docking, it was found that neobavaisoflavone has better binding affinity than dapsone and forms a stable protein-ligand complex. Residues GLY.50, THR.88, and VAL.107 play an important role as binding site residues. Conclusion: Further, in vitro and in vivo experimental studies are required to confirm anti-leprosy properties of neobavaisoflavone over drug dapsone.


Assuntos
Dapsona/farmacologia , Di-Hidropteroato Sintase/antagonistas & inibidores , Isoflavonas/farmacologia , Hansenostáticos/farmacologia , Simulação de Acoplamento Molecular , Mycobacterium leprae/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Mycobacterium leprae/enzimologia , Compostos Fitoquímicos/farmacologia , Ligação Proteica
13.
J Agric Food Chem ; 67(40): 11198-11209, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31532988

RESUMO

The importance of inhibition sensitivity for xylanase functionality in bread making was investigated using mutants of the wild-type Bacillus subtilis xylanase (XBSTAXI), sensitive to Triticum aestivum xylanase inhibitor (TAXI). XBSNI, a mutant with reduced sensitivity to TAXI, and XBSTI, a mutant sensitive to all wheat endogenous proteinaceous inhibitors (TAXI, Xylanase Inhibiting Protein and Thaumatin-like Xylanase Inhibitor) were used. The higher inhibition sensitivity of XBSTAXI and XBSTI compared to XBSNI was associated with a respective 7- and 53-fold increase in enzyme dosage required for a maximal increase in bread loaf volume. XBSTI and XBSTAXI were only active during the mixing phase and the beginning of fermentation, while XBSNI was able to hydrolyze arabinoxylan until the end of fermentation. In spite of this difference in activity profile, no differences in loaf volume were observed for the different xylanases at optimal concentrations. Dough extensional viscosity analysis suggests that increased water availability as a result of xylanase activity favors starch-starch and starch-gluten interactions and drives the improvement in bread loaf volume.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Pão/análise , Endo-1,4-beta-Xilanases/antagonistas & inibidores , Endo-1,4-beta-Xilanases/química , Inibidores Enzimáticos/química , Proteínas de Plantas/química , Bacillus subtilis/química , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Inibidores Enzimáticos/metabolismo , Farinha/análise , Manipulação de Alimentos , Hidrólise , Mutação , Proteínas de Plantas/metabolismo , Triticum/química , Triticum/metabolismo , Viscosidade
14.
Molecules ; 24(16)2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31405060

RESUMO

Novel antimicrobial classes are in desperate need for clinical management of infections caused by increasingly prevalent multi-drug resistant pathogens. The protein-protein interaction between bacterial RNA polymerase (RNAP) and the housekeeping sigma initiation factor is essential to transcription and bacterial viability. It also presents a potential target for antimicrobial discovery, for which a hit compound (C3) was previously identified from a pharmacophore model-based in silico screen. In this study, the hit compound was experimentally assessed with some rationally designed derivatives for the antimicrobial activities, in particular against Streptococcus pneumoniae and other pathogens. One compound, C3-005, shows dramatically improved activity against pneumococci compared to C3. C3-005 also attenuates S. pneumoniae toxin production more strongly than existing classes of antibiotics tested. Here we demonstrate a newly validated antimicrobial agent to address an overlooked target in the hit-to-lead process, which may pave the way for further antimicrobial development.


Assuntos
Anti-Infecciosos , Proteínas de Bactérias/antagonistas & inibidores , Toxinas Bacterianas/biossíntese , Fator sigma/antagonistas & inibidores , Streptococcus pneumoniae/metabolismo , Células A549 , Anti-Infecciosos/síntese química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Células Hep G2 , Humanos , Streptococcus pneumoniae/patogenicidade
15.
Molecules ; 24(17)2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466322

RESUMO

A series of Schiff bases 14-25 were designed and synthesized for evaluation of their antibacterial properties against multi-drug resistant bacteria (MDRB). The antibacterial activities of Schiff bases 14-25 showed that most of the synthesized compounds displayed a significant antibacterial activity. Assessment of in silico ADMET properties (absorption, distribution, metabolism, excretion and toxicity) of Schiff bases illustrates that all derivatives showed agreement to the Lipinski's rule of five. Further enzymatic assay aided by molecular docking study demonstrated that compound 18 is a potent inhibitor of staphylococcus aureus DNA gyrase and dihydrofolate reductase kinases. This study could be valuable in the discovery of new potent antimicrobial agents.


Assuntos
Antibacterianos/síntese química , Pirazóis/química , Bases de Schiff/síntese química , Staphylococcus aureus/enzimologia , Antibacterianos/química , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Simulação por Computador , DNA Girase/metabolismo , Antagonistas do Ácido Fólico/síntese química , Antagonistas do Ácido Fólico/química , Antagonistas do Ácido Fólico/farmacologia , Modelos Moleculares , Simulação de Acoplamento Molecular , Estrutura Molecular , Bases de Schiff/química , Bases de Schiff/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Tetra-Hidrofolato Desidrogenase/metabolismo , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/química , Inibidores da Topoisomerase II/farmacologia
16.
BMC Complement Altern Med ; 19(1): 197, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375097

RESUMO

BACKGROUND: The present study was aimed to evaluate the molecular level anticaries effect of different medicinal plants against Streptococcus mutans (S.mutans) glucosyltransferases (gtf). METHODS: A total of six natural sources named as Terminalia chebula (T.chebula), Psidium guajava (P.guajava), Azadirachta indica (A.indica) and Pongamia pinnata (P.pinnata); two essential oils, clove (Syzygium aromaticum) and peppermint oil (Mentha piperita) were selected as test samples. Hydroalcoholic plant extracts and essential oils were examined for their inhibitory potential on gtf isolated from S.mutans. Polyherbal mouth wash was prepared and its effect on gtf activity was compared with commercial chlorhexidine mouth wash (5%w/v). Enzyme kinetic study was carried out in order to explore the molecular mechanism of enzyme action. RESULTS: Out of six natural sources tested, A.indica has shown maximum inhibitory effect of 91.647% on gtf and T.chebula has shown IC50 of 1.091 mg/ml which is significant when compared to standard chlorhexidine. From the final result of kinetic analysis it was found that T.chebula, P.guajava and P.pinnata have show uncompetitive inhibition where as A.indica has shown non-competitive inhibition. Surprisingly, both essential oils have shown allosteric inhibition (sigmoidal response). The polyherbal moutwash has shown significant inhibitory potential on gtf (95.936%) when compared to commercial chlorhexidine mouthwash (p < 0.05). CONCLUSION: All the tested samples have shown considerable gtf inhibitory action. Moreover polyherbal mouth wash has shown promising noncompetitive inhibitory activity against gtf and it could be the future formulation to combat dental caries.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Glucosiltransferases/química , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Streptococcus mutans/enzimologia , Antibacterianos/química , Cárie Dentária/tratamento farmacológico , Cárie Dentária/microbiologia , Desenho de Drogas , Inibidores Enzimáticos/química , Humanos , Cinética , Antissépticos Bucais/química , Antissépticos Bucais/farmacologia , Extratos Vegetais/química , Streptococcus mutans/efeitos dos fármacos
17.
Pak J Pharm Sci ; 32(3 (Supplementary)): 1179-1183, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31303588

RESUMO

The current article discusses the activities of several synthesized metal heterochelates in in-vitro as anti-ulcer agents followed by their docking study. For this purpose, two important ligands like 8-hydroxyquinoline and DL-methionine were used in synthesis of heterochelates of metal including Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II), Cd (II) and Pb (II). It was observed that these complexes showed excellent urease inhibition activities in which thiourea was the standard having IC50 value 21.6 ± 0.12µM. The Cu (II) complex showed potent inhibitory activity (22.6 ± 0.72 µM) when compared with the standard thiourea (21.6±0.12µM) among the nine synthesized complexes while Mn (II), Fe (III), Cd (II) and Pb (II) also showed better inhibitory activities. The urease inhibitory activities of hetercochelates also tested and validated by docking analysis.


Assuntos
Quelantes/química , Inibidores Enzimáticos/farmacologia , Urease/antagonistas & inibidores , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Quelantes/farmacologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Simulação de Acoplamento Molecular , Sporosarcina/enzimologia , Urease/química , Urease/metabolismo
18.
ACS Chem Biol ; 14(8): 1727-1736, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31310497

RESUMO

Bacterial resistance represents a major health threat worldwide, and the development of new therapeutics, including innovative antibiotics, is urgently needed. We describe a discovery platform, centered on in silico screening and in vivo bioluminescence resonance energy transfer in yeast cells, for the identification of new antimicrobials that, by targeting the protein-protein interaction between the ß'-subunit and the initiation factor σ70 of bacterial RNA polymerase, inhibit holoenzyme assembly and promoter-specific transcription. Out of 34 000 candidate compounds, we identified seven hits capable of interfering with this interaction. Two derivatives of one of these hits proved to be effective in inhibiting transcription in vitro and growth of the Gram-positive pathogens Staphylococcus aureus and Listeria monocytogenes. Upon supplementation of a permeability adjuvant, one derivative also effectively inhibited Escherichia coli growth. On the basis of the chemical structures of these inhibitors, we generated a ligand-based pharmacophore model that will guide the rational discovery of increasingly effective antibacterial agents.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , Indóis/farmacologia , Fator sigma/antagonistas & inibidores , Antibacterianos/toxicidade , Bacillales/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Descoberta de Drogas , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Holoenzimas/metabolismo , Humanos , Indóis/toxicidade , Ligantes , Testes de Sensibilidade Microbiana , Estudo de Prova de Conceito , Ligação Proteica/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Fator sigma/metabolismo
19.
Nat Commun ; 10(1): 2917, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31266949

RESUMO

Novel antibacterial agents are needed to address the emergence of global antibiotic resistance. MraY is a promising candidate for antibiotic development because it is the target of five classes of naturally occurring nucleoside inhibitors with potent antibacterial activity. Although these natural products share a common uridine moiety, their core structures vary substantially and they exhibit different activity profiles. An incomplete understanding of the structural and mechanistic basis of MraY inhibition has hindered the translation of these compounds to the clinic. Here we present crystal structures of MraY in complex with representative members of the liposidomycin/caprazamycin, capuramycin, and mureidomycin classes of nucleoside inhibitors. Our structures reveal cryptic druggable hot spots in the shallow inhibitor binding site of MraY that were not previously appreciated. Structural analyses of nucleoside inhibitor binding provide insights into the chemical logic of MraY inhibition, which can guide novel approaches to MraY-targeted antibiotic design.


Assuntos
Antibacterianos/química , Bactérias/enzimologia , Proteínas de Bactérias/química , Produtos Biológicos/química , Inibidores Enzimáticos/química , Nucleosídeos/antagonistas & inibidores , Transferases/química , Aminoglicosídeos/química , Arginina/análogos & derivados , Arginina/química , Bactérias/química , Bactérias/genética , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Transferases/antagonistas & inibidores , Transferases/genética , Transferases/metabolismo
20.
Lett Appl Microbiol ; 69(3): 161-167, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267555

RESUMO

Efflux-mediated multidrug resistance is a well-known phenomenon facilitated by multidrug resistant (MDR) transporters. One of the approaches to counteract efflux-mediated resistance is the use of MDR pump inhibitors, and thus be used in combination with the conventional antibiotics to treat deadly diseases like typhoid fever. We have previously reported that STY4874, an efflux transporter of Salmonella serotype Typhi, exhibited promising characteristics as MDR pump. In this study, we aimed to get an insight into possible STY4874 inhibitors of plant origin. STY4874 was overexpressed in Escherichia coli and extracts from pomegranate peel, milk thistle seeds and reserpine, a synthetic plant alkaloid, were screened for inhibition of ciprofloxacin efflux. The extracts of milk thistle seeds and reserpine when incubated with ciprofloxacin showed statistically significant STY4874-mediated inhibitory activity, rendering the efflux pump inactive and hence early growth inhibition of host cells compared with cells expressing efflux pump and incubated only with ciprofloxacin. This efflux pump inhibitory activity was further confirmed by time-kill experiments. This study is the first to report on efflux pump inhibition of S. Typhi STY4874 and results can be extended towards its close homologues such as MdfA and MdtM from E. coli. SIGNIFICANCE AND IMPACT OF THE STUDY: Understanding and combating resistance governed by multidrug efflux transporters is an ongoing research intensive area, affecting treatment of various nosocomial and endemic/epidemic infections. Confronting drug resistance requires that inhibitors debilitating the underlying mechanisms should be included in combination therapy. One such example is the prescription of clavulanic acid as combination therapy with amoxicillin, collectively called as co-amoxiclav to combat ß-lactamase-mediated resistance. However, research related to finding the inhibitors of efflux transporters, the resistance mechanism distinct from ß-lactamase mediated resistance is at an early stage. The current study finds that plant-derived inhibitors can be an option towards restraining efflux-mediated resistance.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Escherichia coli/efeitos dos fármacos , Cardo Mariano/química , Proteínas de Transporte de Monossacarídeos/antagonistas & inibidores , Extratos Vegetais/farmacologia , Reserpina/farmacologia , Salmonella typhi/efeitos dos fármacos , Antibacterianos/farmacologia , Ciprofloxacino/farmacologia , Farmacorresistência Bacteriana/genética , Proteínas de Escherichia coli , Testes de Sensibilidade Microbiana
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