目的 研究阿魏酸的抗氧化作用及分子反應(yīng)機(jī)制。方法 用DPPH自由基清除試驗(yàn)，以L-抗壞血酸為陽(yáng)性對(duì)照檢測(cè)阿魏酸的自由基清除能力，使用量子計(jì)算化學(xué)密度泛函理論（DFT）方法研究阿魏酸清除活性自由基的機(jī)制。結(jié)果 阿魏酸對(duì)DPPH自由基的清除能力較強(qiáng)，半數(shù)有效濃度（EC₅₀）值為7.75 μg/mL，僅次于L-抗壞血酸（3.53 μg/mL），阿魏酸C-4位酚羥基取代為甲氧基后抗氧化活性大幅度下降；量子化學(xué)密度泛函理論計(jì)算顯示，阿魏酸酚羥基上氫原子向自由基的轉(zhuǎn)移的作用機(jī)制在熱力學(xué)和動(dòng)力學(xué)上均是合理的。結(jié)論 阿魏酸具有與L-抗壞血酸強(qiáng)度接近的抗氧化活性，關(guān)鍵活性位點(diǎn)為結(jié)構(gòu)中的酚羥基，氫原子轉(zhuǎn)移為阿魏酸抗氧化活性的主要作用機(jī)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