Preparation, Characterization, and DNA Binding Studies of Water-Soluble Quercetin–Molybdenum(VI) Complex

Abstract

DNA binding studies of flavonoids are needed to understand the reaction mechanism and improve drugs that target DNA. Quercetin (Q) is one of the most common flavonoids that can chelate metal ions and interact with double-stranded DNA. In the present work, UV absorption spectrophotometry, viscosimetry, circular dichroism, and fluorescence spectroscopic techniques were employed to study the interaction of water-soluble quercetin--molybdenum(VI) complex [Q-Mo(VI)] with calf thymus DNA. The binding constants (K(b)) for the complex with DNA were estimated to be 2.9 × 10(3) through spectroscopic titrations. Upon addition of the complex, significant decreases were observed in the viscosity of calf thymus DNA. Circular dichroic spectra indicated that there are certain detectable conformational changes in the DNA double helix when complex was added. Further, competitive methylene blue binding studies with fluorescence spectroscopy have shown that the complex can bind to DNA through nonintercalative mode. The experimental results suggest that Q-Mo(VI) binds to DNA via an outside binding mode.

Synthesis, characterization and study of antioxidant activity of quercetin–magnesium complex

“…1B). Complexation of metal cations by Q has already been reported for a large number of metals (Mo(VI), Fe(II), Fe(III), Cu(II), Zn(II), Al(III), Tb(III), Pb(II), Co(II) and many other cations) and in these studies different stoichiometric ratios can be seen between different metals and quercetin as a ligand [15][16][17][18][19][20][21][22].…”

“…Collect the dark yellow product and washed with methanol to remove the uncreative part of the reagent, dried the product in vacuum desiccators, yielded the brown yellowish product. Analysis found: Mg, 6.23%; C, 51.51%; H, 2.34%; calculated for C 15 …”

Spectroscopic and molecular modeling studies of human serum albumin interaction with propyl gallate

“…Fluorescence spectroscopy has usually been used to investigate the molecular interaction(s) between ligands and biomacromolecules due to its high sensitivity [18][19][20] Table 1, which indicate that that there is one independent class of binding site on HSA for PG and K b increases with the rising temperature.…”

Síntese, caracterização e estudo das propriedades de um novo complexo mononuclear contendo quercetina e íon Ga(III)

“…sugere que o íon Ga(III) esteja ligado ao grupo fenólico 3-OH e à carbonila 4-oxo do anel C. 36 Segundo Dehghan, 28 as evidências que suportam esta sugestão estão relacionadas aos seguintes fatos: o grupo 3-OH é um melhor agente quelante (o que está relacionado com sua maior acidez frente aos demais) e a deslocalização dos elétrons do oxigênio do grupo 3-OH é maior, o que facilita a deslocalização dos elétrons π. O deslocamento batocrômico que ocorre na banda I (de 375 nm na quercetina para 388 nm no complexo) pode ser explicado pela interação do Ga 3+ com o grupo 3-hidroxil da quercetina, resultando em uma redistribuição eletrônica entre a molécula do flavonoide e o íon metálico, formando um sistema ligante π estendido. 28 Baseado em relatos da literatura, sugere-se que o processo em ≈501 nm (ombro) pode estar relacionado ao fenômeno da fluorescência, que é explicado pela excitação e relaxamento dos elétrons do ligante (n → π*), influenciados pelo centro metálico.…”