Devasagayam Thomas P A, Kamat Jayashree P
Cell Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Indian J Exp Biol. 2002 Jun;40(6):680-92.
The biological significance of singlet oxygen (1O2), an electronically excited species of oxygen, has been realized only in the last two decades. This was mainly due to the lack of proper methodology to generate this reactive oxygen species (ROS) in pure form and its reactions with biological molecules. Recent studies, using newly developed detection methods, show that 1O2 being generated in many biological systems, can significantly and quite often adversely alter several crucial biomolecules including DNA, proteins and lipids with undesirable consequences including cytotoxicity and/or disesase development. The reactions of 1O2 with the biological molecules are rather specific, as compared to other ROS. There are various compounds, mainly derived from natural sources that offer protection against damage induced by 1O2. Among the antioxidants carotenoids are the most effective singlet oxygen quenchers followed by tocopherols and others. The same reactive species if generated specifically in diseased states such as cancer can lead to the cure of the disease, and this principle is utilized in the newly developing modality of cancer treatment namely photodynamic therapy. Singlet oxygen, in low concentrations can also act as signaling molecule with several biological implications. This review clearly brings out the biological significance of 1O2.
单线态氧（1O2）是氧的一种电子激发态物种，其生物学意义直到最近二十年才被认识到。这主要是由于缺乏以纯净形式生成这种活性氧物种（ROS）及其与生物分子反应的适当方法。最近的研究使用新开发的检测方法表明，在许多生物系统中产生的1O2会显著且常常不利地改变包括DNA、蛋白质和脂质在内的几种关键生物分子，产生包括细胞毒性和/或疾病发展等不良后果。与其他ROS相比，1O2与生物分子的反应相当具有特异性。有各种主要源自天然来源的化合物可提供针对1O2诱导损伤的保护作用。在抗氧化剂中，类胡萝卜素是最有效的单线态氧猝灭剂，其次是生育酚和其他物质。如果在诸如癌症等疾病状态下特异性产生相同的活性物种，则可导致疾病的治愈，并且这一原理被用于新出现的癌症治疗方式即光动力疗法中。低浓度的单线态氧也可作为具有多种生物学意义的信号分子。这篇综述清楚地揭示了1O2的生物学意义。
