Tošović Jelena, Marković Svetlana, Dimitrić Marković Jasmina M, Mojović Miloš, Milenković Dejan
University of Kragujevac, Faculty of Science, Department of Chemistry, 12 Radoja Domanovića, 34000 Kragujevac, Serbia.
University of Kragujevac, Faculty of Science, Department of Chemistry, 12 Radoja Domanovića, 34000 Kragujevac, Serbia.
Food Chem. 2017 Dec 15;237:390-398. doi: 10.1016/j.foodchem.2017.05.080. Epub 2017 May 20.
Although chlorogenic acid (5CQA) is an important ingredient of various foods and beverages, mechanisms of its antioxidative action have not been fully clarified. Besides electron spin resonance experiment, this study includes thermodynamic and mechanistic investigations of the hydrogen atom transfer (HAT), radical adduct formation (RAF), sequential proton loss electron transfer (SPLET), and single electron transfer - proton transfer (SET-PT) mechanisms of 5CQA in benzene, ethanol, and water solutions. The calculations were performed using the M06-2X/6-311++G(d,p) level of theory and CPCM solvation model. It was found that SET-PT is not a plausible antioxidative mechanism of 5CQA. RAF pathways are faster, but HAT yields thermodynamically more stable radical products, indicating that in acidic and neutral media 5CQA can take either HAT or RAF pathways. In basic environment (e.g. at physiological pH) SPLET is the likely antioxidative mechanism of 5CQA with extremely high rate.
尽管绿原酸（5 - 咖啡酰奎宁酸）是各种食品和饮料中的一种重要成分，但其抗氧化作用机制尚未完全阐明。除了电子自旋共振实验外，本研究还包括对绿原酸在苯、乙醇和水溶液中的氢原子转移（HAT）、自由基加合物形成（RAF）、顺序质子损失电子转移（SPLET）和单电子转移 - 质子转移（SET - PT）机制的热力学和机理研究。计算使用M06 - 2X/6 - 311++G(d,p)理论水平和CPCM溶剂化模型进行。结果发现，SET - PT不是绿原酸可行的抗氧化机制。RAF途径更快，但HAT产生热力学上更稳定的自由基产物，这表明在酸性和中性介质中，绿原酸可以采取HAT或RAF途径。在碱性环境（如生理pH值）中，SPLET可能是绿原酸具有极高速率的抗氧化机制。
