RESUMO
Fluorescence imaging in clinical diagnostics and biomedical research relies to a great extent on the use of small organic fluorescent probes. Because of the difficulty of combining fluorescent and molecular-recognition properties, the development of such probes has been severely restricted to a number of well-known fluorescent scaffolds. Here we demonstrate that autofluorescing druglike molecules are a valuable source of bioimaging probes. Combinatorial synthesis and screening of chemical libraries in droplet microarrays allowed the identification of new types of fluorophores. Their concise and clean assembly by a multicomponent reaction presents a unique potential for the one-step synthesis of thousands of structurally diverse fluorescent molecules. Because they are based upon a druglike scaffold, these fluorophores retain their molecular recognition potential and can be used to design specific imaging probes.
Assuntos
Técnicas de Química Combinatória/métodos , Descoberta de Drogas/métodos , Corantes Fluorescentes/química , Análise em Microsséries/métodos , Corantes Fluorescentes/síntese química , Imagem Molecular , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/químicaRESUMO
A collection of 3-substituted indole derivatives was prepared using nucleophilic addition of indoles to nitrones. The compounds were then tested for their antibacterial activity against almost thirty bacterial strains representative of common human pathogens. Two types of indolic molecules inhibit the growth of Staphylococcus aureus, including MRSA and VISA strains, with MIC values ranging from 8 to 16 mg/L.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Indóis/química , Indóis/farmacologia , Antibacterianos/síntese química , Infecções Bacterianas/tratamento farmacológico , Humanos , Indóis/síntese química , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Various alpha,alpha-disubstituted 2-pyrrolidinylmethanols are efficiently prepared in a single step from ketones using a SmI2-mediated cross-coupling with 1-pyrroline N-oxide. The N-hydroxy-alpha,alpha-diphenylprolinol is also easily prepared and resolved.
Assuntos
Inibidores Enzimáticos , Análise Serial de Proteínas , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Humanos , Hidrazinas/química , Estrutura Molecular , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Análise Serial de Proteínas/instrumentação , Análise Serial de Proteínas/métodos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tensão Superficial , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismoRESUMO
The synthesis of 37 1-(1H-indol-3-yl)ethanamine derivatives, including 12 new compounds, was achieved through a series of simple and efficient chemical modifications. These indole derivatives displayed modest or no intrinsic anti-staphylococcal activity. By contrast, several of the compounds restored, in a concentration-dependent manner, the antibacterial activity of ciprofloxacin against Staphylococcus aureus strains that were resistant to fluoroquinolones due to overexpression of the NorA efflux pump. Structure-activity relationships studies revealed that the indolic aldonitrones halogenated at positionâ 5 of the indole core were the most efficient inhibitors of the S.â aureus NorA efflux pump. Among the compounds, (Z)-N-benzylidene-2-(tert-butoxycarbonylamino)-1-(5-iodo-1H-indol-3-yl)ethanamine oxide led to a fourfold decrease of the ciprofloxacin minimum inhibitory concentration against the SA-1199B strain when used at a concentration of 0.5â mg L(-1) . To the best of our knowledge, this activity is the highest reported to date for an indolic NorA inhibitor. In addition, a new antibacterial compound, tert-butyl (2-(3-hydroxyureido)-2-(1H-indol-3-yl)ethyl)carbamate, which is not toxic for human cells, was also found.
Assuntos
Aminas/química , Antibacterianos/química , Proteínas de Bactérias/antagonistas & inibidores , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Staphylococcus aureus/metabolismo , Aminas/síntese química , Aminas/farmacologia , Antibacterianos/síntese química , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Indóis/química , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
An efficient synthesis of new type fluorescent amino acids is described. The Fmoc-protected dyes can be prepared in a four-step procedure with approximately 30% overall yield from aminofluoresceins and other inexpensive commercially available precursors. The dyes are much more photostable compared to fluorescein and exhibit constant pH-independent fluorescence that is advantageous in biological applications. The Fmoc-protected fluorescent amino acids are ready for use in solid phase peptide synthesis. As a proof of concept, a fluorogenic papain substrate was synthesized and employed for on-bead detection of the protease activity. By using a novel technique for quantitative analysis of bead fluorescence, a approximately 2.7-fold increase in mean bead brightness was measured and was attributed to substrate cleavage by papain. The new type fluorescent amino acids seem to be a promising tool for the synthesis of fluorescent peptide ligands and fluorogenic protease substrates.
Assuntos
Aminoácidos/metabolismo , Fluoresceína/química , Peptídeo Hidrolases/metabolismo , Hidrólise , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Especificidade por SubstratoRESUMO
The synthesis of a new type of fluorogenic ester substrates is described. Prepared from fluorescein in three steps with common commercially available precursors, they all generate bright green fluorescence upon proteolysis. Their particular structure allows the same substrate be used to report enzymatic activity of various proteases from serine and cysteine superfamilies. The substrate cleavage is sensitive to specific protease inhibitors providing a tool for inhibitor screening.