Fadda Angela, Barberis Antonio, Sanna Daniele
Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Traversa La Crucca, 3., 07100 Sassari, Italy.
Istituto di Scienze delle Produzioni Alimentari, Consiglio Nazionale delle Ricerche, Traversa La Crucca, 3., 07100 Sassari, Italy.
Food Chem. 2018 Feb 1;240:174-182. doi: 10.1016/j.foodchem.2017.07.076. Epub 2017 Jul 18.
The Fenton reaction is used to produce hydroxyl radicals for the evaluation of the antioxidant activity of plant extracts. In this paper the parameters affecting the production of hydroxyl radicals and their spin trapping with DMPO were studied. The use of quinolinic acid (Quin) as an Fe(II) ligand was proposed for antioxidant activity determination of Green tea, orange juice and asparagus extracts. Quin, buffers and pH affect the DMPO-OH signal intensity of the EPR spectra. Quin/Fe(II) and low pH enhance the OH generation. Phosphate and Tris-HCl buffers decrease the signal intensity measured in Fe(II)-sulfate and Fe(II)-Quin systems. The extracts were analyzed with Fenton systems containing Fe(II)-sulfate and Fe(II)-Quin with and without buffer. The highest activity was shown with Fe(II)-Quin without buffer, this system being less influenced by pH and chelating agents present in the extracts. This paper will help researchers to better design spin trapping experiments for food matrices.
芬顿反应用于产生羟基自由基，以评估植物提取物的抗氧化活性。本文研究了影响羟基自由基产生及其与DMPO自旋捕获的参数。提出使用喹啉酸（Quin）作为Fe（II）配体来测定绿茶、橙汁和芦笋提取物的抗氧化活性。Quin、缓冲液和pH值会影响电子顺磁共振光谱的DMPO-OH信号强度。Quin/Fe（II）和低pH值会增强OH的生成。磷酸盐和Tris-HCl缓冲液会降低在硫酸铁（II）和喹啉酸铁（II）系统中测得的信号强度。使用含有硫酸铁（II）和喹啉酸铁（II）且有或无缓冲液的芬顿体系对提取物进行分析。无缓冲液的喹啉酸铁（II）体系显示出最高活性，该体系受提取物中pH值和螯合剂的影响较小。本文将帮助研究人员更好地设计针对食品基质的自旋捕获实验。
