| Baicalein, which is the effective active ingredient of Chinesetraditional medicine Scutellaria baicalensis, has already exertedtheir effects as a clinical medicine.5,6,7-Trihydroxyflavone is thechemical name of baicalein. Ruthenium element located Ⅷ transitionmetal of Groups. Platinum,Palladium and other precious metals canbe studied as anticancer drugs or catalyst. Baicalein-copper,baicalein-iron and baicalein-zinc complexes showed good biologicalactivity, while the Baicalein-Ruthenium complex has not studied yet.This experiment used baicalein and Ruthenium(III) element asresearch object to synthetic baicalein-ruthenium complex. Thestructural characterization of complex used instrumental analysismethod to determine the formula. Baicalein-ruthenium complex wasstudied in vitro anti-oxidation experiments to determine theantioxidant capacity. The research of baicalein-ruthenium complexand Human Serum Albumin studied fluorescence spectra in order toprovide some theoretical basis of pharmacological activity researchand development applications of baicalein and baicalein-rutheniumcomplex. The main results were as follows: (1) Baicalein-ruthenium complex was synthesized using baicaleinand ruthenium trichloride in the oxygen-free, anhydrous and weakalkaline conditions. The baicalein-ruthenium complex was brownpowder solid. The complex can be dissolved in dimethyl sulfoxide andDimethyl formamide, also can be dissolved in weak alkaline aqueoussolution, slightly soluble in ethanol, methanol and water, insoluble inchloroform, ethyl acetate and petroleum ether. The reaction processof coordination obtained by instrumental analysis was in the5-phenolic hydroxyl in A ring and oxygen atom of carbonyl in the C ringof baicalein with ruthenium trichloride. The coordinating ratio was3:1, which was3mol baicalein reacted with1mol ruthenium trichloride.SEM photographs and X-ray powder diffraction showed that complexbecame amorphous form after coordination reaction, while the formof baicalein was crystal. The Complex formula was (C15H9O5)3Ru7H2O, molecular weight was1033.99D. The conductivity ofbaicalein-ruthenium complexe was very small in pH=7.4solution,which indicating that complex is a covalent complex, which wasstable in solution.(2) In vitro antioxidant experiments showed the newly synthesizedcomplexes have certain antioxidant capacity. That depend on the5,6,7-phenolic hydroxyl and large conjugated system of baicaleinmolecules. The newly synthesized complex has somephysicochemical properties and some new properties. The Complexscavenges DPPH radical ability was better than superoxide anionradical. Because the complex is fat soluble, the reaction ofscavenging superoxide anion system is water-soluble, so the complexlost a little scavenging ability. The total oxidizing power of complex was same as the ligand, while the total reducing power of complexwas not stronger than ligand. The coordination reaction changed thestructure of baicalein，the number of phenolic hydroxyl groups wasdecreased, electron transfer was accelerating, the new conjugatedsystem was formed, the spatial structure was changing.(3) The results of Fluorescence Spectra of the interaction ofbaicalein-ruthenium complex with human serum protein suggestedthat baicalein-ruthenium complex can quench the fluorescence ofHSA in the condition of25℃,pH=7.4. The quenching effect is moreobvious at37℃.And fluorescence spectra also occurs some blue shift.By Calculating Stern-Volmer equation, obtained the bimolecularquenching rate constant Kq and bimolecular quenching constant Ksv.And Kq value is much larger than2.0×1010L/(mol s), the value ofKq and Ksv decreases with increasing temperature, The results showthat the quencher and fluorescence form complexes substance,which lead to the quenching fluorescent. We can determine thequenching process of HSA by baicalein-ruthenium complex was astatic quenching process. By calculating the binding constant Ka andnumber of binding sites between the complex with the HSA indicatestrong binding interactions between the small molecule complex withHSA. At different temperature, The thermodynamic parameters ofBaicalein-ruthenium complex with HSA were ΔG＜0,ΔH＜0， ΔS＜0,which obtained by Van’t Hoff equation. The results showed that thecombine process between the complexes and HSA can go onspontaneously; the binding reaction is an exothermic process. Thechemical interactions force between Baicalein-ruthenium complexand HSA mainly were van der Waals forces and hydrogen bonds. In summary, the coordination reaction between Baicalein withruthenium trichloride can generate baicalein-ruthenium complex,which own some specific biological activity, at slight alkalineenvironment. This complex has a certain antioxidant capacity.Complex can combine with human serum albumin (HSA) to quench thefluorescence of HSA. This experiment can provide a theoretical basisfor the development of anticancer drugs and the quantitativedetection of protein... |
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