Rodríguez Jorge, Olea-Azar Claudio, Cavieres Cristina, Norambuena Ester, Delgado-Castro Tomás, Soto-Delgado Jorge, Araya-Maturana Ramiro
Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile.
Bioorg Med Chem. 2007 Nov 15;15(22):7058-65. doi: 10.1016/j.bmc.2007.07.013. Epub 2007 Aug 7.
This study was undertaken to investigate the free radical-scavenging and antioxidant activities of various structurally related hydroquinones including hydroxynaphthalenones and dihydroxyanthracenones. Electron spin resonance spectroscopy and spin trapping techniques were used to evaluate the ability of hydroquinones to scavenge hydroxyl, diphenylpicrylhydrazyl, and galvinoxyl radicals. In addition, the oxygen radical absorbing capacity assay using fluorescein (ORAC-FL) was used to obtain the relative antioxidant capacity of these radicals. The rate constants of the first H atom abstraction by 2,2-diphenyl-2-picrylhydrazyl (k(2)), were obtained under pseudo-first-order conditions. The free radical-scavenging activities and k(2) values discriminate well between hydroxynaphthalenones and dihydroxyanthracenones, showing that the latter have better antioxidant properties. The aforementioned experimental data agree with quantum-chemical results demonstrating the relevance of intramolecular H bonding to radical-scavenging activities.
本研究旨在探究包括羟基萘醌和二羟基蒽醌在内的各种结构相关的对苯二酚的自由基清除和抗氧化活性。采用电子自旋共振光谱和自旋捕集技术来评估对苯二酚清除羟基、二苯基苦味酰基自由基和加尔文氧基自由基的能力。此外，使用基于荧光素的氧自由基吸收能力测定法（ORAC-FL）来获得这些自由基的相对抗氧化能力。在准一级条件下获得了2,2-二苯基-2-苦味酰基自由基（k(2)）夺取第一个氢原子的速率常数。羟基萘醌和二羟基蒽醌之间的自由基清除活性和k(2)值有明显差异，表明后者具有更好的抗氧化性能。上述实验数据与量子化学结果一致，证明了分子内氢键与自由基清除活性的相关性。
