Study On Fluorescent Method For The Determination Of Superoxide And Peroxynitrite Anion Radicals

Numerous reactive oxygen species (ROS) are generated in the course of biology metabolism. Superoxide anion radical (O₂·^-) and peroxynitrite (ONOO-) are two typical ones. They have important relations with aging and diseases.O₂·^- is a toxic oxidizing and can generate other reactive oxygen species by a series of reactions. These reactive oxygen species have further damages to organisms and long resident time. Peroxynitrite, generated from the diffusion-controlled reaction between the nitrogen monoxide and superoxide radicals can cause lipid peroxidation. Peroxynitrite causes DNA damage, enzyme inhibition, apoptosis and bacterial toxicity and has been implicated in various diseases.About 95% of the total free radicals in the body are reactive oxygen species; therefore the research on the ROS has a special significance to human body. Researches of reactive oxygen species can help us explain the causes of diseases better, strengthen effective preventive measures and reduce the injury extent of the body.Because ROS is active, direct determination is difficult. At present, many methods for the indirect determination of superoxide anion radicals and Peroxynitrite have been developed. After having a comprehensive understanding of these methods, based on fluorescence analysis with the advantages of high sensitivity, selectivity and simple operation, the spectrofluorimetric method was used to detect reactive oxygen species. In the paper, three fluorescent probes were synthesized and their selectivity for O₂·^- and peroxynitrite were studied. In addition, the effects of scavenging of reactive oxygen species by some antioxidants were discussed. Three aspects of investigation have been carried out specifically:(1)A novel fluorescent probe, Vanilla aldehyde shrinks was synthesized. The spectrofluorimetric method was developed for the determination of O₂·^- and SOD activity. The optimum experimental conditions were discussed. Furthermore, SOD activity in onions was successfully determined. The results obtained by the suggested method were also compared with those obtained from the standard method.(2) A novel spectrofluorimetric method using fluorescent hydrazide as fluorescent probe was developed for the determination of peroxynitrite. The sensitivity and precision of the method were studied.(3) A novel fluorescent probe, rhodamine 6G hydrazide was synthesized. The spectrofluorimetric method was developed for the determination of peroxynitrite .The effects of interferences and the selectivity for peroxynitrite of the fluorescent probe was investigated. The sensitivity and precision of the method were studied.In the paper, fluorescent hydrazide was synthesized and the study on molecular mechanism of the interaction between peroxynitrite and fluorescent hydrazide by fluorescent spectroscopy was carried out firstly. These results are satisfied.