Huang Dejian, Ou Boxin, Prior Ronald L
Food Science and Technology Program, Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
J Agric Food Chem. 2005 Mar 23;53(6):1841-56. doi: 10.1021/jf030723c.
This review summarizes the multifaceted aspects of antioxidants and the basic kinetic models of inhibited autoxidation and analyzes the chemical principles of antioxidant capacity assays. Depending upon the reactions involved, these assays can roughly be classified into two types: assays based on hydrogen atom transfer (HAT) reactions and assays based on electron transfer (ET). The majority of HAT-based assays apply a competitive reaction scheme, in which antioxidant and substrate compete for thermally generated peroxyl radicals through the decomposition of azo compounds. These assays include inhibition of induced low-density lipoprotein autoxidation, oxygen radical absorbance capacity (ORAC), total radical trapping antioxidant parameter (TRAP), and crocin bleaching assays. ET-based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes color when reduced. The degree of color change is correlated with the sample's antioxidant concentrations. ET-based assays include the total phenols assay by Folin-Ciocalteu reagent (FCR), Trolox equivalence antioxidant capacity (TEAC), ferric ion reducing antioxidant power (FRAP), "total antioxidant potential" assay using a Cu(II) complex as an oxidant, and DPPH. In addition, other assays intended to measure a sample's scavenging capacity of biologically relevant oxidants such as singlet oxygen, superoxide anion, peroxynitrite, and hydroxyl radical are also summarized. On the basis of this analysis, it is suggested that the total phenols assay by FCR be used to quantify an antioxidant's reducing capacity and the ORAC assay to quantify peroxyl radical scavenging capacity. To comprehensively study different aspects of antioxidants, validated and specific assays are needed in addition to these two commonly accepted assays.
本综述总结了抗氧化剂的多方面特性以及抑制自动氧化的基本动力学模型，并分析了抗氧化能力测定的化学原理。根据所涉及的反应，这些测定大致可分为两类：基于氢原子转移（HAT）反应的测定和基于电子转移（ET）的测定。大多数基于HAT的测定采用竞争反应方案，其中抗氧化剂和底物通过偶氮化合物的分解竞争热生成的过氧自由基。这些测定包括抑制诱导的低密度脂蛋白自动氧化、氧自由基吸收能力（ORAC）、总自由基捕获抗氧化参数（TRAP）和藏红花素漂白测定。基于ET的测定测量抗氧化剂还原氧化剂的能力，该氧化剂在被还原时会变色。颜色变化程度与样品中的抗氧化剂浓度相关。基于ET的测定包括福林-西奥尔特试剂（FCR）总酚测定、Trolox等效抗氧化能力（TEAC）、铁离子还原抗氧化能力（FRAP）、使用铜（II）配合物作为氧化剂的“总抗氧化潜力”测定以及DPPH。此外，还总结了其他旨在测量样品对单线态氧、超氧阴离子、过氧亚硝酸盐和羟基自由基等生物相关氧化剂的清除能力的测定。基于此分析，建议使用FCR总酚测定来量化抗氧化剂的还原能力，使用ORAC测定来量化过氧自由基清除能力。为了全面研究抗氧化剂的不同方面，除了这两种普遍认可的测定方法外，还需要经过验证的特定测定方法。
