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首页> 外文期刊>International Journal of Electrochemical Science >Effect of UV-A Irradiation and Temperature on the Antioxidant Activity of Quercetin Studied Using ABTS, DPPH and Electrochemistry Methods
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Effect of UV-A Irradiation and Temperature on the Antioxidant Activity of Quercetin Studied Using ABTS, DPPH and Electrochemistry Methods

机译：用ABTS，DPPH和电化学方法研究UV-A辐射和温度对槲皮素抗氧化活性的影响

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The electrochemical oxidation of quercetin was investigated at a Pt electrode using the voltammetrymethods. Quercetin is irreversibly oxidized in at least three electrode steps. The effects of the scan rate(v) and substrate concentration (c) on the electrooxidation were determined. Cyclic voltammograms ofquercetin oxidation were recorded and the following parameters were determined: peak potential (Ep),half-peak potential (Ep/2), half-wave potential (E1/2), anodic peak currents (ipa). The followingparameters were calculated: transfer coefficients (n) and electrode reaction rate constants (kbh). Theinvestigation results prove the exchange of one electron and one proton in the first step followed by achemical reaction. The hydroxyl group of ring B at position 3is oxidized. Quercetin electrooxidationoccurs according to the EC mechanism. Then, the hydroxyl group of ring B at position 4is oxidised.The ipa is linear with the quercetin concentration. Considering the investigation results and quantumchemistry calculations, the quercetin electrooxidation mechanism was proposed. Electrochemistry andradical scavenging methods confirmed the high antioxidant activity of quercetin. The stability ofquercetin against photooxidation (irradiation UVA) and thermooxidation is relatively high. FTIRspectrum shows no significant changes after ageing in the structure of quercetin. Quercetin exhibitedgood reduction properties in the oxidation process.
机译：使用伏安法在Pt电极上研究了槲皮素的电化学氧化。槲皮素在至少三个电极步骤中被不可逆地氧化。确定扫描速率（v）和底物浓度（c）对电氧化的影响。记录槲皮素氧化的循环伏安图，并确定以下参数：峰电位（Ep），半峰电位（Ep / 2），半波电位（E1 / 2），阳极峰电流（ipa）。计算出以下参数：传递系数（n）和电极反应速率常数（kbh）。研究结果证明，第一步交换一个电子和一个质子，然后发生化学反应。位置3上的环B的羟基被氧化。槲皮素电氧化是根据EC机制发生的。然后，B环上4位的羟基被氧化.ipa与槲皮素浓度成线性关系。结合研究结果和量子化学计算，提出了槲皮素电氧化机理。电化学和自由基清除方法证实了槲皮素具有很高的抗氧化活性。槲皮素抗光氧化（辐照UVA）和热氧化的稳定性较高。 FTIR光谱显示槲皮素的结构在老化后没有显着变化。槲皮素在氧化过程中表现出良好的还原性能。

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