RESUMEN
The title compound, 3-[(benzo-1,3-dioxol-5-yl)amino]-4-methoxycyclobut-3-ene-1,2-dione, C12H9NO5 (3), is a precursor to an antimycobacterial squaramide. Block-shaped crystals of a monoclinic form (3-I, space group P21/c, Z = 8, Z' = 2) and needle-shaped crystals of a triclinic form (3-II, space group P-1, Z = 4, Z' = 2) were found to crystallize concomitantly. In both crystal forms, R22(10) dimers assemble through N-H...O=C hydrogen bonds. These dimers are formed from crystallographically unique molecules in 3-I, but exhibit crystallographic Ci symmetry in 3-II. Twinning by pseudomerohedry was encountered in the crystals of 3-II. The conformations of 3 in the solid forms 3-I and 3-II are different from one another but are similar for the unique molecules in each polymorph. Density functional theory (DFT) calculations on the free molecule of 3 indicate that a nearly planar conformation is preferred.
RESUMEN
Tuberculosis (TB) is a leading cause of death from a single infectious agent, Mycobacterium tuberculosis (Mtb). Although progress has been made in TB control, still about 10 million people worldwide develop TB annually and 1.5 million die of the disease. The rapid emergence of aggressive, drug-resistant strains and latent infections have caused TB to remain a global health challenge. TB treatments are lengthy and their side effects lead to poor patient compliance, which in turn has contributed to the drug resistance and exacerbated the TB epidemic. The relatively low output of newly approved antibiotics has spurred research interest toward alternative antibacterial molecules such as silver nanoparticles (AgNPs). In the present study, we use the natural biopolymer alginate to serve as a stabilizer and/or reductant to green synthesize AgNPs, which improves their biocompatibility and avoids the use of toxic chemicals. The average size of the alginate-capped AgNPs (ALG-AgNPs) was characterized as nanoscale, and the particles were round in shape. Drug susceptibility tests showed that these ALG-AgNPs are effective against both drug-resistant Mtb strains and dormant Mtb. A bacterial cell-wall permeability assay showed that the anti-mycobacterial action of ALG-AgNPs is mediated through an increase in cell-wall permeability. Notably, the anti-mycobacterial potential of ALG-AgNPs was effective in both zebrafish and mouse TB animal models in vivo. These results suggest that ALG-AgNPs could provide a new therapeutic option to overcome the difficulties of current TB treatments.
RESUMEN
Tuberculosis (TB) is a disease that affects one-third of the world's population. Although currently available TB drugs have many side effects, such as nausea, headache and gastrointestinal discomfort, no new anti-TB drugs have been produced in the past 30â¯years. Therefore, the discovery of a new anti-TB agent with minimal or no side effects is urgently needed. Many previous works have reported the effects of medicinal plants against Mycobacterium tuberculosis (MTB). However, none have focused on medicinal plants from the Middle Eastern and North African (MENA) region. This review highlights the effects of medicinal plants from the MENA region on TB. Medicinal plants from the MENA region have been successfully used as traditional medicine and first aid against TB related problems. A total of 184 plants species representing 73 families were studied. Amongst these species, 93 species contained more active compounds with strong anti-MTB activity (crude extracts and/or bioactive compounds with activities of 0-100⯵g/ml). The extract of Inula helenium, Khaya senegalensis, Premna odorata and Rosmarinus officinalis presented the strongest anti-MTB activity. In addition, Boswellia papyrifera (Del) Hochst olibanum, Eucalyptus camaldulensis Dehnh leaves (river red gum), Nigella sativa (black cumin) seeds and genus Cymbopogon exhibited anti-TB activity. The most potent bioactive compounds included alantolactone, octyl acetate, 1,8-cineole, thymoquinone, piperitone, α- verbenol, citral b and α-pinene. These compounds affect the permeability of microbial plasma membranes, thus kill the mycobacterium spp. As a conclusion, plant species collected from the MENA region are potential sources of novel drugs against TB.
RESUMEN
Starting from the analysis of the hypothetical binding mode of our previous furan-based hit (I), we successfully achieved our objective to replace the nitro moiety, leading to the disclosure of a new lead exhibiting a strong activity against MbtI. Our best candidate 1 h displayed a Ki of 8.8 µM and its antimycobacterial activity (MIC99 = 250 µM) is conceivably related to mycobactin biosynthesis inhibition. These results support the hypothesis that 5-phenylfuran-2-carboxylic derivatives are a promising class of MbtI inhibitors.
Asunto(s)
Antituberculosos/química , Antituberculosos/farmacología , Inhibidores Enzimáticos/farmacología , Furanos/química , Liasas/antagonistas & inhibidores , Sitios de Unión , Inhibidores Enzimáticos/química , Liasas/química , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Mycobacterium bovis/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Tuberculosis is the leading cause of death from a single infectious agent worldwide; therefore, the need for new antitubercular drugs is desperate. The recently validated target salicylate synthase MbtI is the first enzyme involved in the biosynthesis of mycobactins, compounds able to chelate iron, an essential cofactor for the survival of Mycobacterium tuberculosis in the host. Here, we report on the synthesis and biological evaluation of chromane-based compounds as new potential inhibitors of MbtI. Our approach successfully allowed the identification of a novel lead compound (1), endowed with a promising activity against this enzyme (IC50 = 55 µM). Molecular modeling studies were performed in order to evaluate the binding mode of 1 and rationalize the preliminary structure-activity relationships, thus providing crucial information to carry out further optimization studies.
Asunto(s)
Antituberculosos/química , Proteínas Bacterianas/antagonistas & inhibidores , Ácido Corísmico/química , Cromanos/química , Inhibidores Enzimáticos/química , Liasas/antagonistas & inhibidores , Mycobacterium tuberculosis/química , Secuencias de Aminoácidos , Antituberculosos/síntesis química , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Dominio Catalítico , Ácido Corísmico/metabolismo , Cromanos/síntesis química , Inhibidores Enzimáticos/síntesis química , Expresión Génica , Cinética , Liasas/química , Liasas/genética , Liasas/metabolismo , Simulación del Acoplamiento Molecular , Mycobacterium tuberculosis/enzimología , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Estructura Secundaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Relación Estructura-Actividad , Especificidad por Sustrato , TermodinámicaRESUMEN
In recent years, several small natural cyclopeptides and cyclodepsipeptides were reported to have antimycobacterial activity. Following this lead, a synthetic pathway was developed for a small series of 12-membered ring compounds with one amide and two ester bonds (cyclotridepsipeptides). Within the series, the ring system proved to be necessary for growth inhibition of Mycobacterium smegmatis and Mycobacterium tuberculosis in the low micromolar range. Open-chain precursors and analogues were inactive. The compounds modulated autophosphorylation of the mycobacterial protein kinase B (PknB). PknB inhibitors were active at µM concentration against mycobacteria while inducers were inactive. PknB regulates the activity of the mycobacterial reductase InhA, the target of isoniazid. The activity of the series against Mycobacterium bovis BCG InhA overexpressing strains was indistinguishable from that of the parental strain suggesting that they do not inhibit InhA. All substances were not cytotoxic (HeLaâ¯>â¯5⯵g/ml) and did not show any significant antiproliferative effect (HUVECâ¯>â¯5⯵g/ml; K-562â¯>â¯5⯵g/ml). Within the scope of this study, the molecular target of this new type of small cyclodepsipeptide was not identified, but the data suggest interaction with PknB or other kinases may partly cause the activity.
Asunto(s)
Antituberculosos/síntesis química , Proteínas Bacterianas/antagonistas & inhibidores , Depsipéptidos/química , Oxidorreductasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Antituberculosos/química , Antituberculosos/farmacología , Proteínas Bacterianas/metabolismo , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Depsipéptidos/síntesis química , Depsipéptidos/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Pruebas de Sensibilidad Microbiana , Mycobacterium smegmatis/efectos de los fármacos , Mycobacterium smegmatis/metabolismo , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/metabolismo , Oxidorreductasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
The emergence of multi- and extensively-drug resistant tubercular (MDR- and XDR-TB) strains of mycobacteria has limited the use of existing therapies, therefore new drugs are needed. Dihydrofolate reductase (DHFR) has recently attracted much attention as a target for the development of anti-TB agents. This study aimed to develop selective M. tuberculosis DHFR inhibitors using rationale scaffolding design and synthesis, phenotype-oriented screening, enzymatic inhibitory study, whole cell on-target validation, molecular modeling, and in vitro DMPK determination to derive new anti-TB agents. 2,4-diamino-1-phenyl-1,3,5-triazaspiro[5.5]undeca-2,4-dienes 20b and 20c were identified as selective M. tuberculosis DHFR inhibitors, showing promising antimycobacterial activities (MIC50: 0.01 µM and MIC90: 0.025 µM on M. tuberculosis H37Rv). This study provided compelling evidence that compound 20b and 20c exerted whole cell antimycobacterial activity through DHFR inhibition. In addition, these two compounds exhibited low cytotoxicity and low hemolytic activity. The in vitro DMPK and physiochemical properties suggested their potential in vivo efficacy.
Asunto(s)
Antagonistas del Ácido Fólico/farmacología , Mycobacterium tuberculosis/enzimología , Compuestos de Espiro/farmacología , Tetrahidrofolato Deshidrogenasa/metabolismo , Animales , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Antagonistas del Ácido Fólico/síntesis química , Antagonistas del Ácido Fólico/química , Células Hep G2 , Humanos , Masculino , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Estructura Molecular , Mycobacterium tuberculosis/citología , Ratas , Compuestos de Espiro/síntesis química , Compuestos de Espiro/química , Relación Estructura-ActividadRESUMEN
PURPOSE: Multi- and extensively drug-resistant tuberculosis (TB) is a global threat to human health. It requires immediate action to seek new antitubercular compounds and devise alternate strategies. Nanomaterials, in the present scenario, have opened new avenues in medicine, diagnosis, and therapeutics. In view of this, the current study aims to determine the efficacy of phytogenic metal nanoparticles to inhibit mycobacteria. METHODS: Silver (AgNPs), gold (AuNPs), and gold-silver bimetallic (Au-AgNPs) nanoparticles synthesized from medicinal plants, such as Barleria prionitis, Plumbago zeylanica, and Syzygium cumini, were tested against Mycobacterium tuberculosis and M. bovis BCG. In vitro and ex vivo macrophage infection model assays were designed to determine minimum inhibitory concentration (MIC) and half maximal inhibitory concentration of nanoparticles. Microscopic analyses were carried out to demonstrate intracellular uptake of nanoparticles in macrophages. Besides this, biocompatibility, specificity, and selectivity of nanoparticles were also established with respect to human cell lines. RESULTS: Au-AgNPs exhibited highest antitubercular activity, with MIC of <2.56 µg/mL, followed by AgNPs. AuNPs did not show such activity at concentrations of up to 100 µg/mL. In vitro and ex vivo macrophage infection model assays revealed the inhibition of both active and dormant stage mycobacteria on exposure to Au-AgNPs. These nanoparticles were capable of entering macrophage cells and exhibited up to 45% cytotoxicity at 30 µg/mL (ten times MIC concentration) after 48 hours. Among these, Au-AgNPs synthesized from S. cumini were found to be more specific toward mycobacteria, with their selectivity index in the range of 94-108. CONCLUSION: This is the first study to report the antimycobacterial activity of AuNPs, AgNPs, and Au-AgNPs synthesized from medicinal plants. Among these, Au-AgNPs from S. cumini showed profound efficiency, specificity, and selectivity to kill mycobacteria. These should be investigated further to develop novel TB nanoantibiotics.
Asunto(s)
Antituberculosos/química , Antituberculosos/farmacología , Nanopartículas del Metal/química , Plantas Medicinales/química , Acanthaceae/química , Línea Celular , Evaluación Preclínica de Medicamentos/métodos , Oro/farmacología , Humanos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Pruebas de Sensibilidad Microbiana , Mycobacterium bovis/efectos de los fármacos , Mycobacterium tuberculosis/efectos de los fármacos , Plumbaginaceae/química , Plata/farmacologíaRESUMEN
Resistance among mycobacteria leading to multidrug-resistant and extensively drug-resistant tuberculosis is a major threat. However, nanotechnology has provided new insights in drug delivery and medicine development. This is the first comparative report to determine the activity of chemically and biologically synthesised silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) against mycobacteria. Screening data revealed the high mycobactericidal efficiency of AgNPs, with minimum inhibitory concentrations (MICs) of <3µg/mL, whereas no such activity was exhibited by AuNPs at concentrations up to 100µg/mL. Moreover, in vitro and ex vivo THP-1 infection model assays showed greater efficacy of chemical AgNPs compared with biogenic AgNPs to inhibit active and dormant stage mycobacterial growth. Up to 40% cytotoxicity against human cell lines was observed at a AgNP concentration of 10× MIC (30µg/mL) after 48h. AgNPs were shown to have more specificity towards mycobacteria than towards other Gram-negative and Gram-positive pathogenic bacteria. The selectivity index was found to be in the range of 11-23, indicating the potential of these nanoparticles for use in developing new therapeutics for tuberculosis.
Asunto(s)
Antibacterianos/farmacología , Oro/farmacología , Nanopartículas del Metal , Mycobacterium bovis/efectos de los fármacos , Mycobacterium tuberculosis/efectos de los fármacos , Plata/farmacología , Antibacterianos/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Oro/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Plata/metabolismoRESUMEN
Tuberculosis (TB) is a disease caused mainly by infection of Mycobacterium tuberculosis affecting more than ten million people around the world. Despite TB can be treated, the rise of MDR-TB and XDR-TB cases put the disease in a worrying status. As pyrazinamide-resistant strains exhibit low or none pyrazinamidase activity, it is proposed that the active form of pyrazinamide (PZA) is pyrazinoic acid (POA), although this acid has poor penetration in mycobacteria. In this work, we present a convenient one-pot synthesis of 2-chloroethyl pyrazinoate, and its activity in M. tuberculosis H37Rv (ATCC27294) in MIC assay using the MABA technique. The obtained MIC of the compound was 3.96 g/mL, and discussion about the activity profile of some previously evaluated pyrazinoates is also performed.
RESUMEN
After AIDS, tuberculosis (TB) is the leading killer worldwide due to a single infectious agent. Recently, drug-resistant strains of Mycobacterium tuberculosis elicited even more severe versions of TB. Bedaquiline inhibits mycobacterial ATP synthase. It shows potent and selective activity in vitro against M. tuberculosis, and in vivo against murine models of TB. Bedaquiline can be combined with antituberculosis and antiretroviral agents. The product displays good oral absorption, has a long terminal half-life and is metabolized mainly by cytochrome P450 3A4. In a phase II clinical trial in patients with multidrug-resistant TB, bedaquiline (combined with the standard five-drug, second-line TB regimen), showed a time to 50% culture negative conversion of 78 days, with 81.0% and 52.4% efficacy at weeks 24 and 104, respectively. Bedaquiline was generally safe and well tolerated. At the end of 2012, the U.S. Food and Drug Administration approved bedaquiline (Sirturo®) as part of a combination therapy to treat adults with multidrug-resistant TB.