Rajendran M, Ramasamy S, Rajamanickam C, Gandhidasan R, Murugesan R
Department of Chemistry, NMSSVN College, Madurai 625 019, Tamil Nadu, India.
Biochim Biophys Acta. 2003 Jul 23;1622(2):65-72. doi: 10.1016/s0304-4165(03)00100-4.
The aim of this work was to investigate the photodynamic action of electron-rich anthraquinones, viz., cynodontin (CYN) and cynodontin-5,8-dimethylether (CYNM). Both optical and EPR methods are used to detect the generation of singlet oxygen. Based on RNO bleaching, relative to rose bengal (RB), singlet oxygen generating efficiencies of CYN and CYNM are derived to be 0.055 and 0.254, respectively. The formation of superoxide anion via electron transfer to O2 was monitored by optical spectroscopy, using SOD-inhibitable cytochrome c reduction assay. The production of O2-* is enhanced in the presence of electron donors such as EDTA and NADH. Photolysis of CYN and CYNM in DMSO, in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), generates a multi-line EPR spectrum, characteristic of spin adduct mixture of O2-* and OH. Both optical and ESR measurements indicate that O2- (Type I) and 1O2 (Type II) paths are involved in CYN and CYNM photodynamic action.
这项工作的目的是研究富含电子的蒽醌类化合物，即犬齿蛋白（CYN）和犬齿蛋白-5,8-二甲醚（CYNM）的光动力作用。采用光学和电子顺磁共振（EPR）方法检测单线态氧的生成。基于RNO漂白，相对于孟加拉玫瑰红（RB），CYN和CYNM的单线态氧生成效率分别为0.055和0.254。通过光光谱法，使用超氧化物歧化酶（SOD）抑制的细胞色素c还原测定法监测通过电子转移到O₂形成超氧阴离子的过程。在存在电子供体如乙二胺四乙酸（EDTA）和烟酰胺腺嘌呤二核苷酸（NADH）的情况下，超氧阴离子（O₂⁻·）的产生会增强。在5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）存在下，CYN和CYNM在二甲基亚砜（DMSO）中的光解产生多线EPR光谱，这是O₂⁻·和·OH自旋加合物混合物的特征。光学和电子自旋共振（ESR）测量均表明，O₂⁻·（I型）和¹O₂（II型）途径参与了CYN和CYNM的光动力作用。
