槲皮素(3,3’,4’,5,7-五羟基黄酮)是含量丰富的黄酮类化合物之一,主要存在于药用植物、水果、树叶和蔬菜中。它显示了带I吸收(300~380nm),这被认为是与B环肉桂酰体系有关,带II吸收(240~280nm)与A环苯甲酰体系有关。由于槲皮素结构中存在螯合位点,它能够与一系列阳离子形成复合物,这些阳离子具有抗氧化活性、DNA保护、抗肿瘤和抗癌活性以及抗炎作用。
巴西巴拉那联邦研究所的Taiane Souza de Castilho、Tatiane Brescovites Matias、Keller Paulo Nicolini等人基于黄酮类槲皮素和过量金属氯化物之间的相互作用的置换试验可以得到槲皮素和Ca 2+ 2+ 2+ 2+ 3 2+ 3 2+ 4 2+
文章摘要
ABSTRACT
Taiane Souza de Castilho, Tatiane Brescovites Matias, Keller Paulo Nicolini, JaquelineNicolini
Instituto Federal do Paraná – IFPR, Lacoppi – Laboratório de Corantes e Processos Pirolíticos, Departamento de Química, Palmas, PR, Brazil
Abstract
A displacement test based on the interaction between the flavonoid quercetin and an excess of metal chloride allows the determination of the binding constant for the reaction between quercetin and Ca
2+
, Mg2+
and Ni2+
. The values obtained were 2.20 ± 1.77 ×103
for Ca2+
, 1.37 ± 0.59 × 103
for Mg2+
and 7.03 ± 1.04 × 104
for Ni2+
, and all interactions showed type 1:1 stoichiometry, as determined by titration and by the method of continuous variations (Job’s method). The complexion effect was observed qualitatively through a colorimetric change in the medium (yellow → neon yellow) and spectroscopically through a bathochromic shift in the absorption band of quercetin in the presence of metals. This investigation serves as a tool for the development and testing of materials capable of capturing toxic metal ions or favoring the absorption of beneficial ions (in relation to the human metabolism) through the construction of efficient bioorganic systems. The results reported herein allow understanding of this detection system, indicating the following ascending order of the binding constants (