目的 研究阿魏酸的抗氧化作用及分子反应机制。方法 用DPPH自由基清除试验，以L-抗坏血酸为阳性对照检测阿魏酸的自由基清除能力，使用量子计算化学密度泛函理论（DFT）方法研究阿魏酸清除活性自由基的机制。结果 阿魏酸对DPPH自由基的清除能力较强，半数有效浓度（EC₅₀）值为7.75 μg/mL，仅次于L-抗坏血酸（3.53 μg/mL），阿魏酸C-4位酚羟基取代为甲氧基后抗氧化活性大幅度下降；量子化学密度泛函理论计算显示，阿魏酸酚羟基上氢原子向自由基的转移的作用机制在热力学和动力学上均是合理的。结论 阿魏酸具有与L-抗坏血酸强度接近的抗氧化活性，关键活性位点为结构中的酚羟基，氢原子转移为阿魏酸抗氧化活性的主要作用机制。

Objective To study the antioxidant activity of ferulic acid and the molecular reaction mechanism.Methods The DPPH radical scavenging test was used to evaluate the radical scavenging ability of ferulic acid, with L -ascorbic acid as a positive control. The mechanism of ferulic acid's scavenging of active free radicals was investigated using quantum chemical DFT theoretical methods.Results Ferulic acid demonstrated strong scavenging ability against DPPH radicals, with an EC₅₀ value of 7.75 μg/mL, and the L -ascorbic acid was 3.53 μg/mL. The antioxidant activity decreased significantly when the phenolic hydroxyl group at position 4 of ferulic acid was replaced with a methoxy group. Quantum chemical density functional theory calculations showed that the transfer of a hydrogen atom from the phenolic hydroxyl group of ferulic acid to the free radical is a reasonable mechanism both thermodynamically and kinetically.Conclusion Ferulic acid exhibits antioxidant activity comparable to that of L -ascorbic acid, with the key active site being the phenolic hydroxyl group in its structure. The transfer of hydrogen atoms is the main mechanism for the antioxidant activity of ferulic acid.

R966