Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco No. 186, Colonia Vicentina C.P. 09340, México DF.
J Phys Chem B. 2011 Dec 29;115(51):15430-8. doi: 10.1021/jp209776x. Epub 2011 Dec 5.
The reactions of uric and 1-methyluric acids in nonpolar environments, as well as those of the corresponding urate anions in aqueous solution, with (•)OH, (•)OCH(3), (•)OOH, and (•)OOCH(3) have been studied using the density functional theory. Different mechanisms of reactions have been taken into account, and their relative importance on the antiradical activity of these compounds is analyzed. Both uric and methyluric acids are better scavengers in aqueous solution than in nonpolar media, which indicates that the urate anions are the most active species. The free radical scavenging activity of the studied compounds was found to be excellent for (•)OH, and very good for (•)OCH(3). In addition, 1-methyluric acid is predicted to moderately protect against peroxyl oxidation, while the protective effects of uric acid against these particular species are not expected to be significant. In addition, 1-methyluric acid was found to be a better radical scavenger than its precursor, caffeine, suggesting that the antiradical activity of the latter might be explained by the action of its metabolites, rather than by its direct activity.
已使用密度泛函理论研究了尿酸和 1-甲基尿酸在非极性环境中的反应，以及相应的尿酸阴离子在水溶液中与（•）OH、（•）OCH（3）、（•）OOH 和（•）OOCH（3）的反应。考虑了不同的反应机制，并分析了它们对这些化合物的抗自由基活性的相对重要性。尿酸和甲基尿酸在水溶液中的清除自由基活性均优于非极性介质，这表明尿酸阴离子是最活跃的物种。研究化合物对（•）OH 的清除自由基活性非常出色，对（•）OCH（3）的清除自由基活性也非常好。此外，预测 1-甲基尿酸对过氧自由基氧化具有适度的保护作用，而尿酸对这些特定物种的保护作用预计不会显著。此外，发现 1-甲基尿酸比其前体咖啡因更能清除自由基，这表明后者的抗自由基活性可能是通过其代谢物的作用来解释的，而不是其直接活性。
