Carvalho Joana R B, Meireles Andreia N, Marques Sara S, Gregório Bruno J R, Ramos Inês I, Silva Eduarda M P, Barreiros Luisa, Segundo Marcela A
LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, R Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
TOXRUN-Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116 Gandra, Portugal.
Antioxidants (Basel). 2023 Feb 17;12(2):505. doi: 10.3390/antiox12020505.
The analysis and interpretation of data retrieved from Oxygen Radical Absorbance Capacity (ORAC) assays represent a challenging task. ORAC indexes originate from different mathematical approaches often lacking correct elucidation of kinetic features concerning radical scavenging reactions by antioxidant compounds. In this work, the expression of ORAC values as area under fluorescein (FL) decay curves (AUC) and lag time are critically compared. This multi-parametric analysis showed the extension of radical scavenging reactions beyond the lag time period for caffeic acid, gallic acid, reduced glutathione and quercetin, extending their antioxidant protection of FL. Ethanol delayed the reaction of both FL and antioxidant compounds with free radical species generated from 2,2'-azobis(2-amidinopropane) dihydrochloride thermolysis. Trolox equivalent values, commonly used to express ORAC values, were more affected by the differences in radical scavenging kinetics between the reference and the tested antioxidant compounds when calculated from AUC than from lag time. These findings stressed the importance of choosing calibrator compounds presenting ORAC kinetics similar to samples to prevent biased estimation of the antioxidant capacity. Additionally, the framework proposed here provides a sustainable analytical method for the evaluation of antioxidant capacity, with an AGREE score of 0.73.
对从氧自由基吸收能力（ORAC）测定中获取的数据进行分析和解释是一项具有挑战性的任务。ORAC指数源自不同的数学方法，这些方法往往缺乏对抗氧化剂化合物清除自由基反应动力学特征的正确阐释。在这项工作中，对以荧光素（FL）衰减曲线下面积（AUC）和滞后时间表示的ORAC值进行了严格比较。这种多参数分析表明，咖啡酸、没食子酸、还原型谷胱甘肽和槲皮素的自由基清除反应在滞后时间段之后仍有延续，从而扩展了它们对FL的抗氧化保护作用。乙醇延迟了FL和抗氧化剂化合物与2,2'-偶氮二异丁脒二盐酸盐热解产生的自由基的反应。通常用于表示ORAC值的Trolox当量值，从AUC计算时比从滞后时间计算时更容易受到参考抗氧化剂化合物和受试抗氧化剂化合物之间自由基清除动力学差异的影响。这些发现强调了选择具有与样品相似ORAC动力学的校准化合物以防止抗氧化能力的偏差估计的重要性。此外，这里提出的框架提供了一种可持续的抗氧化能力评估分析方法，AGREE评分为0.73。
