目的 研究阿魏酸的抗氧化作用及分子反應機制。方法 用DPPH自由基清除試驗，以L-抗壞血酸為陽性對照檢測阿魏酸的自由基清除能力，使用量子計算化學密度泛函理論（DFT）方法研究阿魏酸清除活性自由基的機制。結果 阿魏酸對DPPH自由基的清除能力較強，半數有效濃度（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；量子化學密度泛函理論計算顯示，阿魏酸酚羥基上氫原子向自由基的轉移的作用機制在熱力學和動力學上均是合理的。結論 阿魏酸具有與L-抗壞血酸強度接近的抗氧化活性，關鍵活性位點為結構中的酚羥基，氫原子轉移為阿魏酸抗氧化活性的主要作用機制。

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