五种酚类抗氧化剂活性差异的理论解释(英文)

Theoretical elucidation of activity differences of five phenolic antioxidants

目的:验证目前关于抗氧化剂的结构-活性关系及理论计算方法的有效性。方法:首先用结构-活性关系初步解释五种抗氧化剂的活性差异,其次用半经验量子化学方法AMl计算抗氧化剂与其自由基生成热的差值(△HOF值),并以此为理论指标深入阐释五种抗氧化剂的活性差异。结果:计算得出几种抗氧化剂的△HOF值为:阿魏酸,150.58 kJ·mol^(-1);阿魏酸负离子,122.64 kJ·mol^(-1);阿魏酸修饰物,137.70 kJ·mol^(-1);阿魏酸修饰物负离子,118.99 kJ·mol^(-1);丹参素,134.17 kJ·mol^(-1);芦丁,137.83 kJ·mol^(-1);L-EGCG,124.39 kJ·mol^(-1);芍药酮,176.79 kJ·mol^(-1),据此解释了它们抗氧化活性的差别,并探讨了如何进一步提高其抗氧化活性.结论:现有的关于抗氧化剂的结构-活性关系和理论研究方法可以较好地解释实验现象,并可为其结构修饰,进一步提高抗氧化活性提供指导。

AIM: To verify the effectiveness of structure-activity relationship (SAR) and theoretical calculation methods for antioxidants. METHODS: Preliminary elucidation on the differences of activities of 5 antioxidants was performed by SAR. Then semiempirical quantum chemistry method AM1 was employed to calculate the AHOF value, the difference between the heat of formation of antioxidant and its free radical, which was used as a theoretical parameter to elucidate the differences of activities of the antioxidants thoroughly. RESULTS: AHOF values of antioxidants were obtained as follows; ferulic acid, 150.58 kJ·mol-1; anion of ferulic acid, 122.64 kJ ·mol-1; modified ferulic acid, 137.70 kJ·mol-1; anion of modified ferulic acid, 118.99 kJ·mol-1 salvianic acid, 134.17 kJ·mol-1; rutin, 137.83 kJ· mol-1; L-EGCG, 124.39kJ·mol-1; paeonol, 176.79 kJ·mol-1. The differences of the antioxidant activities were elucidated, and how to further enhance the antioxidant activity was investigated as well. CONCLUSION: The SAR and calculation methods are rather effective to elucidate the differences of antioxidant activities, and present some new clues for structural modification of antioxidants to increase their activities.