Knasmüller Siegfried, Nersesyan Armen, Misík Miroslav, Gerner Christopher, Mikulits Wolfgang, Ehrlich Veronika, Hoelzl Christine, Szakmary Akos, Wagner Karl-Heinz
Institute of Cancer Research, Inner Medicine I, Medical University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria.
Br J Nutr. 2008 May;99 E Suppl 1:ES3-52. doi: 10.1017/S0007114508965752.
This article describes the principles and limitations of methods used to investigate reactive oxygen species (ROS) protective properties of dietary constituents and is aimed at providing a better understanding of the requirements for science based health claims of antioxidant (AO) effects of foods. A number of currently used biochemical measurements aimed of determining the total antioxidant capacity and oxidised lipids and proteins are carried out under unphysiological conditions and are prone to artefact formation. Probably the most reliable approaches are measurements of isoprostanes as a parameter of lipid peroxidation and determination of oxidative DNA damage. Also the design of the experimental models has a strong impact on the reliability of AO studies: the common strategy is the identification of AO by in vitro screening with cell lines. This approach is based on the assumption that protection towards ROS is due to scavenging, but recent findings indicate that activation of transcription factors which regulate genes involved in antioxidant defence plays a key role in the mode of action of AO. These processes are not adequately represented in cell lines. Another shortcoming of in vitro experiments is that AO are metabolised in vivo and that most cell lines are lacking enzymes which catalyse these reactions. Compounds with large molecular configurations (chlorophylls, anthocyans and polyphenolics) are potent AO in vitro, but weak or no effects were observed in animal/human studies with realistic doses as they are poorly absorbed. The development of -omics approaches will improve the scientific basis for health claims. The evaluation of results from microarray and proteomics studies shows that it is not possible to establish a general signature of alterations of transcription and protein patterns by AO. However, it was shown that alterations of gene expression and protein levels caused by experimentally induced oxidative stress and ROS related diseases can be normalised by dietary AO.
本文描述了用于研究膳食成分中活性氧（ROS）保护特性的方法的原理和局限性，旨在更好地理解基于科学的食品抗氧化（AO）作用健康声明的要求。目前用于测定总抗氧化能力以及氧化脂质和蛋白质的一些生化测量是在非生理条件下进行的，并且容易产生假象。可能最可靠的方法是测量异前列腺素作为脂质过氧化的参数以及测定氧化性DNA损伤。此外，实验模型的设计对AO研究的可靠性有很大影响：常见策略是通过细胞系体外筛选来鉴定AO。这种方法基于这样的假设，即对ROS的保护是由于清除作用，但最近的研究结果表明，调节参与抗氧化防御的基因的转录因子的激活在AO的作用模式中起关键作用。这些过程在细胞系中没有得到充分体现。体外实验的另一个缺点是AO在体内会被代谢，并且大多数细胞系缺乏催化这些反应的酶。具有大分子结构的化合物（叶绿素、花青素和多酚类）在体外是有效的AO，但在动物/人体研究中，以实际剂量给药时观察到的效果较弱或没有效果，因为它们的吸收很差。 -组学方法的发展将改善健康声明的科学依据。对微阵列和蛋白质组学研究结果的评估表明，不可能通过AO建立转录和蛋白质模式改变的一般特征。然而，研究表明，由实验诱导的氧化应激和ROS相关疾病引起的基因表达和蛋白质水平的改变可以通过膳食AO恢复正常。
