Design, Synthesis And Analytical Application Of A Fluorescent Probe For Dual Detection Of Reactive Oxygen Species/hydrogen Sulfide

Hydrogen sulfide?H₂S?,a colorless gas that smells like rotten eggs,is known as the third liposoluble gas signaling molecular in organism with physiological functions,besides carbon monoxide?CO?and nitrogen monoxide?NO?.Endogenous H₂S is mainly produced by the catalysis of sulfur-containing amino acids?cysteine,homocysteine,etc.?by pyridoxal 5'-phosphate-dependent enzymes including cystathionine beta-synthase,cystathionine-gamma-lyase and cysteine transferase.H₂S is found to be involved in various physiological and pathological processes in nervous system,respiratory system,cardiovascular system as well as digestive system.Reactive oxygen species?ROS?,generated in vivo from the metabolism of oxygen in mitochondria,refer to a variety of oxygenic highly-reactive species including superoxide,hyperoxide and radicals.ROS involve in many physiological and pathological processes,as intracellular and intercellular signaling molecular,which are closely related to damages,aging,inflammation and cancers.Hypochlorous acid?HClO?,as an important ROS in vivo,plays important roles in life activities.Endogenous HClO is produced by the catalysis of chloridion?Cl^-?and hydrogen peroxide?H₂O₂?by intracellular myeloperoxidase?MPO?.Because of its relatively stronger oxidizing property,HClO is involved in various physiological and pathological processes.For one thing,moderate amount of HClO is of benefit to the healing of cells and tissues as well as the inhibition of inflammation,through the regulation of cytokines in immune system.For another,excess amount of HClO induce cell death,tissue damage and a series of diseases.Peroxynitrite?ONOO^-?is another important ROS in vivo,as the production of radical reactions between NO and superoxide anion(O₂^·-).Owing to its relatively stronger oxidizing and nucleophilic property,ONOO^-reacts with many biological molecules and thus is involved in various physiological and pathological processes.On the one hand,ONOO^-assists to adjust the immune function of the body.On the other hand,ONOO^-induces the nitration of tyrosine and the oxidation of nucleic acid,sulfydryl molecules and unsaturated fatty acid containing phospholipid,triggering cell death as a result of mitochondrial dysfunction.Two organic fluorescent probes were developed in this dissertation for dual detection,among which one simultaneously detected H₂S and HClO while another discriminably detected H₂S and ONOO^-.The detailed contents of this work are listed as follows.?1?A fluorescent probe,named RPC-1,was developed to simultaneously detect H₂S and HClO,based on the combining of coumarin and rhodamine with typical azide group for recognizing H₂S and thiolactone group for detecting HClO.Two-photon imaging was carried out on confocal microscopy in this section.Drug induced damage of cells and tissues was evaluated in living cells and in hepatic tissues,with the alone or in combination of antidepressant drugs,fluoxetine and duloxetine.At the same time,it is proved that the body protects by up-regulating endogenous hydrogen sulfide and N-acetylcysteine?NAC?exerts its anti-hepatic damage effect by increasing the content of endogenous hydrogen sulfide.The study results provide a suitable analysis tool for the assessment and treatment of drug induced liver injury.?2?A fluorescent probe,named RC-Br,was developed to discriminably detect H₂S and ONOO^-,based on the nucleophilic addition of H₂S and ONOO^-to RC-Br.The results showed that that the probe produced distinguishable dual excitation and dual emission signals.Characterizing of rapid response and high sensitivity,RC-Br was used in cell imaging and supposed to be an effective analytical tool for studies on the interaction between H₂S and ONOO^-in biological systems.