Estudo da interação entre flavonóides e a albumina do soro humano
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Data
2012-06-21
Autores
Caruso, Ícaro Putinhon [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os flavonóides são uma grande classe de polifenóis ocorrendo de forma natural amplamente distribuídos nas plantas, essas moléculas exibem algumas atividades farmacológicas importantes como anti-inflamatória, antioxidante, anticancerígena e antibacteriana. A interação entre os flavonóides Rutina (Ru) e Guaijaverina (Gua) e a Albumina do Soro Humano (HSA) em pH 7,0 fisiológico foi investigado usando a técnica de espectroscopia de fluorescência de estado estacionário, cálculo ab initio e de modelagem molecular. A partir da supressão de fluorescência da HSA pelos flavonóides, a constante de supressão de Stern-Volmer ( SVK ) e sua forma modificada ( aK ) foram calculadas em 298, 303 e 308 K, como também os parâmetros termodinâmicos correspondentes H , G e S , para cada flavonóide. A análise do equilíbrio de ligação foi utilizada para determinar os valores do número de sítios de ligação ( n ) e a constante de ligação ( bK ) para a Rutina e a Guaijaverina em 298, 303 e 308 K. A distância média entre o doador (HSA-214Trp ) e o aceitador (Ru e Gua) foi estimada de acordo com a teoria de transferência de energia ressonante fluorescente. A otimização geométrica dos flavonóides Rutina e Guaijaverina foi realizada nos seus estados fundamentais usando o funcional DFT/B3LYP ab initio com um conjunto de bases 6-31G(d,p) utilizado nos cálculos. O cálculo de modelagem molecular indica que os flavonóides se localizam no sítio I da HSA, dentro do bolso hidrofóbico do subdomínio IIA. Os resultados teóricos obtidos pela modelagem molecular corroboram com os dados de espectroscopia de fluorescência
Flavonoids are a large class of naturally occurring polyphenols widely distributed in plants, these molecules exhibit some important pharmacological activities like anti-inflammatory, antioxidant, anticancer, and antibacterial. The interaction between Rutina and Guaijaverin flavonoids and Human Serum Albumin (HSA) at physiological pH 7.0 was investigated by using the technique of fluorescence spectroscopy, ab initio and molecular modeling calculation. From the fluorescence quenching of the HSA by flavonoids, the Stern-Volmer quenching constant ( SVK ) and its modified form ( aK ) were calculated at 298 , 303 and K308 , as well as the corresponding thermodynamic parameters H , G and S , for each flavonoid. Analysis of binding equilibria was utilized to determine the number of binding sites ( n ) and binding constants ( bK ) values for Rutin and Guaijaverin at 298 , 303 and K308 . The average distance between donor (HSA-214Trp ) e acceptor (Ru and Gua) was estimated according to the theory of fluorescence resonance energy transfer. The geometry optimization of Rutin and Guaijaverin flavonoids was performed in its ground state by using ab initio DFT/B3LYP functional with a 6-31G(d,p) basis set applied in calculations. Molecular modeling calculation indicated that the flavonoids are located in site I of HSA, within the hydrophobic pocket of the subdomain IIA. The theoretical results obtained by molecular modeling are corroborated by the fluorescence spectroscopy data
Flavonoids are a large class of naturally occurring polyphenols widely distributed in plants, these molecules exhibit some important pharmacological activities like anti-inflammatory, antioxidant, anticancer, and antibacterial. The interaction between Rutina and Guaijaverin flavonoids and Human Serum Albumin (HSA) at physiological pH 7.0 was investigated by using the technique of fluorescence spectroscopy, ab initio and molecular modeling calculation. From the fluorescence quenching of the HSA by flavonoids, the Stern-Volmer quenching constant ( SVK ) and its modified form ( aK ) were calculated at 298 , 303 and K308 , as well as the corresponding thermodynamic parameters H , G and S , for each flavonoid. Analysis of binding equilibria was utilized to determine the number of binding sites ( n ) and binding constants ( bK ) values for Rutin and Guaijaverin at 298 , 303 and K308 . The average distance between donor (HSA-214Trp ) e acceptor (Ru and Gua) was estimated according to the theory of fluorescence resonance energy transfer. The geometry optimization of Rutin and Guaijaverin flavonoids was performed in its ground state by using ab initio DFT/B3LYP functional with a 6-31G(d,p) basis set applied in calculations. Molecular modeling calculation indicated that the flavonoids are located in site I of HSA, within the hydrophobic pocket of the subdomain IIA. The theoretical results obtained by molecular modeling are corroborated by the fluorescence spectroscopy data
Descrição
Palavras-chave
Biologia molecular, Flavonoides, Albumina, Flavonoids
Como citar
CARUSO, Ícaro Putinhon. Estudo da interação entre flavonóides e a albumina do soro humano. 2012. 67 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2012.