College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China.
Int J Mol Sci. 2019 Mar 22;20(6):1450. doi: 10.3390/ijms20061450.
The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups-via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.
黄酮类化合物的自由基清除活性在很大程度上受其结构的影响。本文采用密度泛函理论（DFT）方法研究了 C3 位取代基对柚皮素抗氧化活性的影响。分析了与三种公认机制相关的反应焓。反应焓与哈米特σ常数之间存在良好的相关性。线性回归得到的方程有助于选择合适的候选物，以合成具有增强抗氧化性能的新型柚皮素衍生物。在气相和苯相中，供电子取代基通过削弱键离解焓（BDE）增强了柚皮素的抗氧化活性。在水相中，通过降低质子亲和力（PA）增强了吸电子基团的抗氧化活性。取代基对柚皮素 BDE 的电子效应主要受共振效应控制，而对柚皮素的电离势（IP）和 PA 的影响主要受场/诱导效应控制。
