The interaction of gatifloxacin （HGA） with bovine serum albumin （BSA） at 15 and 37 ℃ has been investigated by fluorescence quenching spectroscopy in aqueous solution. The bimolecular quenching rate constant was determined by Stem-Volmer curves and the values were Kq=9.28× 10^12 L·mol^-1·s^-1 （15 ℃） and Kq=8.51 ×10^12 L·mol^-1·s^-1 （37 ~C）. The results showed that the fluorescence quenching mechanism of BSA by HGA was a static quenching procedure. The thermodynamic parameters indicated that electrostatic forces played major role in the interaction of BSA with HGA. Studies on the relationship between the concentration of HGA and the fluorescence intensity of BSA showed that BSA and HGA bound at the molar ratio 1 ： 1 and the equilibrium constant K0 was 6.80 ×10^4 L·mol^-1. The binding distances between BSA and HGA and the energy transfer efficiency were obtained based on the Ftrster＇s theory.
Two new complexes （Cp）2Ti （Sal）2 and（Cp）2Ti（Clo）2 （Cp=Cyclopentadienyl η^5-C5H5 ）, have been synthesized in anhydrous THF by the reaction of HSal（o-hydroxybenzoic acid, salicylate acid） or HClo[N-（ m-chloro-phenyl） anthranili acid, acidum clofenamicum] with （Cp）2TiCl2 and characterized by means of elemental analyses, IR, H NMR, ^13C NMR, UV and molar conductivity. In complex （Cp）2Ti（Sal）2 or（Cp）2Ti（Clo）2, the oxygen atom of the carboxyl group coordinates to Ti（Ⅳ） in a monodentate manner. The inhibitory action of the complexes on mouse ear tumefaction caused by croton oil and rat foot granulation growth caused by cotton balls is higher than that of the corresponding ligands HSal, HClo and [ （Cp）2TiCl2 ], whereas their toxicity is lower than those of the free ligands.
N^1,N^1-Dimethylbiguanide hydrochloride （HDMBG,HCl） was introduced as an oral glucose-lowering agent to treat non-insulin dependent diabetes mellitus. In this paper, two solid complexes-trichlorotris（N^5-benzoyl-N^1,N^1-dimethylbiguanidato）neodymium, [Nd（BDMBG）3Cl3）, and chlorobis-[N^5-（o-carboxybenzoyl）-N^1,N^1- dimethylbiguanidato]neodymium, [Nd（CDMBG）2Cl], were synthesized and characterized by elemental analyses, fluorescence spectra, IR, UV, DG, DTA etc. Biological testings were conducted by diabetic rats and ESR. The results showed that both the antidiabetic activity and the inhibition rates （Ih） to superoxide anion free radical （O2） on lipid are in the order as follows： Nd（SDMBG）3 [tris（N^5-salicyloyl-N^1,N^1-dimethylbiguanidato）neodymium]〉 Nd（CDMBG）2Cl≈HDMBG·HCl 〉Nd（BDMBG）3Cl3. It was concluded that different substituents at the o-position of the benzoyl group may affect these two kinds of behaviour to a great extent.
在乙醇中以乙酸稀土或在无水乙醇中以无水氯化钕与二甲双胍(以DMBG表示)反应,合成了二甲双胍乙酸钕、钐和二甲双胍氯化钕3种固态配合物。元素分析、ICP、IR、UV、荧光光谱等测试技术研究表明,配合物的化学组成分别为Re(DMBG)2(CH3COO)3(Re=Nd(Ⅲ),Sm(Ⅲ)离子,CH3COO-为乙酸根)和Nd(DMBG)2(EtO)C l2(EtO为乙氧基阴离子)。通过糖尿病小鼠模型观察了它们的降血糖作用,通过ESR谱测定了对人工脂质体膜超氧自由基的清除率。实验结果表明,二甲双胍乙酸钕[Nd(DMBG)2(CH3COO)3]的降血糖作用和对超氧离子自由基的清除率均高于盐酸二甲双胍(M etform in,D im ethylb iguam ide hydrochloride简称DMBG.HC l),表明其降血糖作用与其抗氧化作用或对细胞膜的保护作用具有相关性。
