Departamento de Farmacia, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile.
Anal Chim Acta. 2013 Feb 6;763:1-10. doi: 10.1016/j.aca.2012.11.051. Epub 2012 Dec 5.
Oxidative stress is associated with several pathologies like cardiovascular, neurodegenerative, cancer and even aging. It has been suggested that a diet rich in antioxidants would be beneficial to human health and a lot of interest is focused on the determination of antioxidant capacity of natural products. Different chemical methods have been developed including the popular ORAC that evaluates the potential of a sample as inhibitor of a target molecule oxidation. Chemical-based methods are useful for screening, they are low cost, high-throughput and yield an index value (expressed as equivalents of Trolox) that allows comparing and ordering different products. More recently, nanoparticles-based assays have been developed to sense the antioxidant power of natural products. However, the antioxidant capacity indexes obtained by chemical assays cannot extrapolate the performance of the sample in vivo. Considering that antioxidant action is not limited to scavenging free radicals but includes upregulation of antioxidant and detoxifying enzymes, modulation of redox cell signaling and gene expression, it is necessary to move to cellular assays in order to evaluate the potential antioxidant activity of a compound or extract. Animal models and human studies are more appropriate but also more expensive and time-consuming, making the cell culture assays very attractive as intermediate testing methods. Cellular antioxidant activity (CAA) assays, activation of redox transcription factors, inhibition of oxidases or activation of antioxidant enzymes are reviewed and compared with the classical in vitro chemical-based assays for evaluation of antioxidant capacity of natural products.
氧化应激与多种病理学有关，如心血管、神经退行性、癌症甚至衰老。有人认为，富含抗氧化剂的饮食对人类健康有益，因此人们对天然产物抗氧化能力的测定产生了浓厚的兴趣。已经开发了不同的化学方法，包括流行的 ORAC，它评估了样品作为目标分子氧化抑制剂的潜力。基于化学的方法对于筛选很有用，它们成本低、高通量，并产生一个指数值（表示为 Trolox 的等效物），可以比较和排序不同的产品。最近，基于纳米粒子的测定方法已经被开发出来，以感知天然产物的抗氧化能力。然而，化学测定获得的抗氧化能力指数不能推断样品在体内的性能。考虑到抗氧化作用不仅限于清除自由基，还包括抗氧化和解毒酶的上调、氧化还原细胞信号和基因表达的调节，因此有必要转向细胞测定，以评估化合物或提取物的潜在抗氧化活性。动物模型和人体研究更合适，但也更昂贵和耗时，因此细胞培养测定作为中间测试方法非常有吸引力。本文综述了细胞抗氧化活性（CAA）测定、氧化还原转录因子的激活、氧化酶的抑制或抗氧化酶的激活，并将其与基于经典体外化学的测定方法进行了比较，以评估天然产物的抗氧化能力。
