Niki Etsuo
Kyoto Prefectural University of Medicine, Kyoto; National Institute of Advanced Industrial Science and Technology, Health Research Institute, Osaka, Japan.
Biomed J. 2014 May-Jun;37(3):106-11. doi: 10.4103/2319-4170.128727.
The radical scavenging antioxidants play an essential role in the maintenance of health and prevention of diseases, and a thorough understanding of the action and capacity of antioxidants is critically important. Despite the assumption that antioxidants must exert beneficial effects against oxidative stress, many large-scale randomized controlled trials gave inconsistent and disappointing results on the prevention of chronic diseases. It is now generally accepted that there is no evidence to support the use of non-discriminative antioxidant supplements for prevention of diseases. On the other hand, recent data show that antioxidants may be effective in the prevention and/or treatment of diseases when the right antioxidant is given to the right subject at the right time for the right duration. Now it is accepted that reactive oxygen species (ROS) act as physiologically important signaling messengers as well as deleterious agents. The signaling ROS are produced in a subtly regulated manner, while many deleterious ROS are produced and react randomly. Free radical-mediated lipid peroxidation products which, in contrast to enzymatic oxidation products, are produced by non-specific mechanisms cause oxidative damage, but may also induce adaptive response to enhance the expression of antioxidant enzymes and compounds. This has raised a question if removal of too many ROS by supplementation of antioxidants may upset the cell signaling pathways and actually increase the risk of chronic diseases. However, it is unlikely that antioxidants impair physiologically essential signaling pathways.
自由基清除抗氧化剂在维持健康和预防疾病方面起着至关重要的作用，因此深入了解抗氧化剂的作用和能力至关重要。尽管人们认为抗氧化剂必然对氧化应激产生有益影响，但许多大规模随机对照试验在预防慢性病方面给出了不一致且令人失望的结果。现在人们普遍认为，没有证据支持使用不加区分的抗氧化剂补充剂来预防疾病。另一方面，最近的数据表明，当在正确的时间、以正确的持续时间将正确的抗氧化剂给予正确的对象时，抗氧化剂可能对疾病的预防和/或治疗有效。现在人们认识到，活性氧（ROS）既是生理上重要的信号信使，也是有害因子。信号性ROS以一种精细调节的方式产生，而许多有害ROS则随机产生并发生反应。与酶促氧化产物不同，自由基介导的脂质过氧化产物通过非特异性机制产生，会造成氧化损伤，但也可能诱导适应性反应以增强抗氧化酶和化合物的表达。这就提出了一个问题，即通过补充抗氧化剂去除过多的ROS是否会扰乱细胞信号通路并实际上增加慢性病的风险。然而，抗氧化剂不太可能损害生理上必需的信号通路。
