Faculty of Science, University of Kragujevac, 12 Radoja Domanovića, 34000 Kragujevac, Serbia.
Faculty of Science, University of Kragujevac, 12 Radoja Domanovića, 34000 Kragujevac, Serbia.
Food Chem. 2016 Nov 1;210:585-92. doi: 10.1016/j.foodchem.2016.05.019. Epub 2016 May 3.
A detailed conformational analysis was performed to determine the most stable conformers of chlorogenic, cryptochlorogenic, and neochlorogenic acids. The simulated and experimental NMR spectra of caffeoylquinic acids are in excellent agreement. The bond dissociation enthalpies, proton affinities, electron transfer enthalpies, ionisation potentials, and proton dissociation enthalpies for these compounds and caffeic acid in benzene, methanol, and water were used for thermodynamic consideration of the major antioxidative mechanisms: HAT (Hydrogen Atom Transfer), SPLET (Sequential Proton-Loss Electron-Transfer), and SET-PT (Single Electron Transfer - Proton Transfer). All compounds are characterised with very similar values of each enthalpy, suggesting that they will exhibit comparable antioxidative activities. This assumption is in perfect accord with the experimental findings. It was suggested that HAT may be the predominant mechanism in nonpolar solvents, while HAT and SPLET are competitive pathways in polar media. All calculations were performed using the B3LYP-D2/6-311++G(d,p) and M06-2X/6-311++G(d,p) levels of theory and CPCM solvation model.
进行了详细的构象分析，以确定绿原酸、隐绿原酸和新绿原酸的最稳定构象。模拟和实验 NMR 谱与咖啡酰奎宁酸非常吻合。这些化合物和咖啡酸在苯、甲醇和水中的键离解焓、质子亲和力、电子转移焓、电离势和质子离解焓用于主要抗氧化机制的热力学考虑：HAT（氢原子转移）、SPLET（顺序质子损失电子转移）和 SET-PT（单电子转移-质子转移）。所有化合物的每个焓值都具有非常相似的值，表明它们将表现出相当的抗氧化活性。这一假设与实验结果完全一致。有人认为，在非极性溶剂中，HAT 可能是主要机制，而在极性介质中，HAT 和 SPLET 是竞争途径。所有计算均使用 B3LYP-D2/6-311++G(d,p)和 M06-2X/6-311++G(d,p)理论水平和 CPCM 溶剂化模型进行。
