Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
Intervalo de ano de publicação
1.
Spectrochim Acta A Mol Biomol Spectrosc ; 222: 117213, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31177010

RESUMO

The interactions of (-)-epigallocatechin-3-Gallate (EGCG) and anthracycline drugs (doxorubicin, DOX and epirubicin, EPI) alone or in combination with human serum albumin (HSA) under physiological condition were studied by fluorescence spectroscopy, UV-vis absorption spectroscopy, circular dichroism (CD) spectroscopy, and dynamic light scattering (DLS). The cytotoxic activity of the single drug, combined drugs, and their complexes with HSA against human cervical cancer HeLa cell line was determined by MTT assay. Fluorescence quenching result and difference spectra of UV absorption revealed the formation of static complex between EGCG, DOX, or EPI and HSA. The binding of EGCG with HSA was driven by both enthalpy and entropy while the binding of DOX or EPI was mainly entropy driven. The nature of binding was expounded based on the effect of sodium chloride, tetrabutylammonium bromide, and sucrose which interfere in electrostatic, hydrophobic, and hydrogen bonding interactions, respectively. Site marker competitive experiments combined with synchronous fluorescence spectra showed that these three ligands mainly bound to subdomain IIA of HSA and were closer to tryptophan residues. In EGCG + DOX/EPI + HSA ternary system, the effect of one drug on the binding ability of another drug was discussed. The influences of the individual and combined binding of EGCG and DOX/EPI on the secondary structure and particle size of HSA were investigated by CD spectroscopy and DLS, respectively. Moreover, the synergistic cytotoxicity of EGCG and DOX/EPI as well as their complexes with HSA were discussed. Obtained results would provide beneficial information on the combination of EGCG and anthracyclines in clinic.


Assuntos
Antineoplásicos/farmacologia , Catequina/análogos & derivados , Doxorrubicina/farmacologia , Epirubicina/farmacologia , Albumina Sérica Humana/metabolismo , Antraciclinas/metabolismo , Antraciclinas/farmacologia , Antibióticos Antineoplásicos/metabolismo , Antibióticos Antineoplásicos/farmacologia , Anticarcinógenos/metabolismo , Anticarcinógenos/farmacologia , Antineoplásicos/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica , Catequina/metabolismo , Catequina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Doxorrubicina/metabolismo , Entropia , Epirubicina/metabolismo , Células HeLa , Humanos , Neoplasias/tratamento farmacológico , Ligação Proteica , Espectrometria de Fluorescência
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 206: 384-395, 2019 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-30170174

RESUMO

The individual and combined interactions of bisphenol F and piceatannol with pepsin were investigated using spectroscopic methods (fluorescence, UV-vis absorption, and circular dichroism spectroscopy), combined with isothermal titration calorimetry and molecular docking. Thermodynamic data showed that hydrogen bonds and van der Waals forces might play a major role for the binding process. Site marking experiments and molecular docking confirmed the binding sites of these two ligands on pepsin. The discrepancy in the binding constant between the binary and ternary systems indicated the competitive binding of piceatannol and bisphenol F to pepsin. Circular dichroism spectra studies suggested that the binding of the two ligands led to a loosening of pepsin backbone. Enzyme activity assays indicated that the inhibition of pepsin activity by piceatannol and bisphenol F was competitive. These results will be helpful to understand the mechanism of piceatannol and bisphenol F affecting the activity of digestive proteases in the sight of the food security.


Assuntos
Compostos Benzidrílicos/química , Pepsina A/química , Fenóis/química , Estilbenos/química , Compostos Benzidrílicos/metabolismo , Sítios de Ligação , Calorimetria , Simulação de Acoplamento Molecular , Pepsina A/metabolismo , Fenóis/metabolismo , Análise Espectral , Estilbenos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA