全反式维甲酸合钇(Ⅲ)配合物对DNA的切割和键合作用(英)

以紫外光谱、荧光光谱、粘度法和凝胶电泳方法研究了全反式维甲酸合钇(Ⅲ)配合物与DNA的作用。结果表明，该配合物能在生理条件下比配体和金属离子更有效地切割质粒DNA，体系离子强度和pH值的变化对配合物的切割活性有较大影响，自由基捕捉剂的加入不影响配合物的切割活性。该配合物对DNA的切割可能通过水解机理进行。该配合物可使DNA的粘度增加，使EB-DNA体系的荧光强度和DNA溶液的紫外吸收强度降低。据此推断，该配合物主要以嵌入方式与DNA作用。     

一种新的吡咯多胺镍配合物的合成及其与DNA的作用研究

合成了一种新的吡咯-多胺金属镍配合物,并用质谱、核磁、红外、摩尔电导、元素分析等多种手段分析了配体和配合物的结构;紫外、荧光和黏度等方法分析了镍配合物与小牛胸腺DNA(CT DNA)的作用,发现配合物以插入方式与DNA结合;电泳法研究发现配合物在反应温度为50～55℃间可将超螺旋pBR 322 DNA完全切割为缺刻产物;细胞水平抗肿瘤实验表明该镍配合物具有一定的抗肝癌活性.     

具有分子内折叠结构锌配合物的合成，与DNA键合及其对DNA切割作用研究

本文报道了一个锌配合物[Zn(bipy)(pmal)(H2O)]·2H2O（其中bipy = 2,2’-联吡啶, pmal = 苯基丙二酸）的合成,晶体结构及其光谱学研究。并通过单晶X射线衍射,元素分析,红外光谱等手段对它进行了表征。同时,利用紫外光谱和荧光光谱方法考察了该配合物与小牛胸腺DNA的键和作用。琼脂糖凝胶电泳实验的结果说明该配合物的平面结构对pBR 322DNA切割作用显著。     

具有切割DNA活性的铬配合物*

铬配合物切割DNA的活性在医学、药学及生物学领域引起了广泛关注。本文综述了具有切割DNA活性的铬配合物的研究进展,介绍了不同价态铬的多种配位模式配合物切割DNA的活性,总结了铬配合物切割DNA的作用机理,展望了不同价态铬配合物的研究和发展方向。     

两个带呋喃悬臂不对称大环双核铜配合物的合成、结构及性质(英文)

合成并表征了2个不对称大环双核铜配合物[Cu2(L1)Cl2]·CH3CN(1)和[Cu2(L2)Br2]·CH3CN·H2O(2)。配合物与CT-DNA的作用通过紫外-可见光谱,粘度实验,圆二色谱和凝胶电泳实验进行了研究。紫外-可见光谱的结果表明配合物与DNA的结合常数分别为6.2×105和7.2×105,圆二色谱的实验表明配合物能与DNA较好的结合,粘度实验表明配合物与DNA的结合为非典型的插入模式,凝胶电泳实验显示配合物通过氧化机理对DNA有较强的切割活性。     

吡啶类单核钴(Ⅱ)配合物的合成、结构、与DNA的相互作用及细胞毒性

合成了一个新的单核钴配合物[Co（L）Cl₂],配体L为吡啶类多齿配体4-甲基-N,N-二（吡啶-2-亚甲基）苯胺。对化合物进行了红外光谱、元素分析、X射线单晶衍射的表征。结果表明配合物的Co（Ⅱ）中心为五配位畸变的三角双锥构型。利用电子吸收、发射光谱和凝胶电泳等方法研究了配合物与DNA的相互作用。结果表明不加诱导剂时该配合物与DNA能表现出一定程度的切割活性,而加入诱导剂过氧化氢后,化学核酸酶活性显著提高。其切割机理为氧化切割机理,其中活性氧可能为·OH和¹O₂,且配合物与DNA的结合部位可能在大沟槽处。另外,用MTT实验测定了该配合物对体外HeLa、BGC-823、NCI-H460肿瘤细胞生长的抑制能力。     

全反式维甲酸合铜(II)配合物对DNA的切割和键合作用

以荧光法、粘度法、凝胶电泳和电化学方法研究了全反式维甲酸合铜(II)配合物与DNA的作用.结果表明,该配合物能在生理条件下有效切割质粒DNA,加入H_2O_2后发现该配合物的切割活性增强,说明该配合物对DNA的切割机理可能有两种:氧化和水解.同时可使DNA的粘度增加,使EB-DNA体系的荧光强度降低.DNA的存在能导致该配合物氧化还原峰电流降低.据此推断,该配合物主要以嵌入方式与DNA作用.     

光谱法研究[Ce(NO_3)_3(Phen)_2]配合物晶体结构及其与DNA之间的相互作用

对配合物[Ce(NO3)3(Phen)2]的吸收光谱、荧光光谱和拉曼光谱进行了归属,研究了该配合物的晶体结构。同时,用光谱法研究了该配合物与DNA之间的相互作用。研究发现,DNA加入后,配合物的紫外吸收峰和表面增强拉曼峰明显降低,而荧光强度明显增强。配合物对EB与DNA作用有竞争。这些表明配合物与DNA有较强的相互作用,并且主要键合模式是插入作用。测得配合物与DNA的键合常数为1·7×105。     

一种有机锡化合物的合成、晶体结构、抗肿瘤及荧光性能(英文)

通过异烟肼和4-N,N-二羟乙基苯甲醛来合成一种席夫碱及其锡配合物,并通过核磁、元素分析以及X-射线单晶衍射来进行结构表征。该平面构型的席夫碱采取二齿配位模式,其中的-C=N-在配位后由反式变为顺式。晶体结构数据以及荧光光谱中的显著红移现象表明锡配合物中的π-共轭体系通过配位反应得以延展。体外细胞毒性数据表明,席夫碱配体及其锡配合物对于A-549,MCF-7和Hela等肿瘤细胞的生长抑制活性要强于顺铂。还通过紫外可见光谱及荧光光谱初步研究了两种化合物与DNA的相互作用,结果表明锡配合物可能通过共价结合来导致DNA双螺旋链变形,而席夫碱分子中的氢键效应及其长平面结构可能会阻碍其嵌入DNA双螺旋链。     

全反式维甲酸合铜(II)配合物对DNA的切割和键合作用

以荧光法、粘度法、凝胶电泳和电化学方法研究了全反式维甲酸合铜(II)配合物与DNA的作用. 结果表明, 该配合物能在生理条件下有效切割质粒DNA, 加入H₂O₂后发现该配合物的切割活性增强, 说明该配合物对DNA的切割机理可能有两种: 氧化和水解. 同时可使DNA的粘度增加, 使EB-DNA体系的荧光强度降低. DNA的存在能导致该配合物氧化还原峰电流降低. 据此推断, 该配合物主要以嵌入方式与DNA作用.     

Topoisomerases inhibitory activities and DNA binding properties of 9-methoxycamptothecin from Nothapodytes nimmoniana (J. Graham) Mabberly

We have reported previously that 9-methoxycamptothecin (MCPT) showed significant antitumor activity in vitro. Here, agarose gel electrophoresis experiments were performed to evaluate MCPT’s unwinding ability toward plasmid DNA and inhibitory activities against topoisomerases (Topo) I and II. Binding properties of MCPT to calf thymus DNA (CT-DNA) were evaluated by UV–vis, melting temperature, fluorescence, circular dichroism methodologies and molecular docking technique. Results showed that MCPT at 100 μM inhibited Topo I activity, but had no effect on Topo II. Studies on the binding properties indicated that minor groove binding was the most probable binding mode of MCPT to DNA. The abilities of MCPT to act as Topo I inhibitor and minor groove binding agent may be related to its strong antitumor activity.     

Spectroscopic Investigation on the Binding of the Antitumoral Pd(II) Complex to Human Serum Albumin

The interaction of human serum albumin (HSA) with 1,10‐phenanthroline‐ethyldithiocarbamatopalladium(II) nitrate complex, [Pd(phen)(Et‐dtc)]NO₃, has been studied by using absorption, fluorescence and circular dichroism spectroscopic measurements. UV‐Vis studies imply that The peptide strands of protein molecules extended more (denatured) upon the addition of Pd(II) complex. This process is spontaneous and exothermic. A fluorescence quenching reaction of Pd(II) complex and HSA was observed and quenching mechanism was suggested as static quenching according to Stern‐Volmer equation. The number of binding sites (n) and apparent association constant (K_A) were calculated using fluorescence quenching data. The circular dichroism results revealed the conformational changes in secondary structure of protein upon its interaction with Pd(II) complex. In these interaction studies, several thermodynamic and binding parameters are also determined which may provide deeper insights into structural changes induced by an antitumor Pd(II) complex on the protein as the metal complex side effects.     

Synthesis,Structures, and Optical and Electrochemical Properties of Benzoporphycenes

The first facile syntheses of free‐base di‐ and tetrabenzoporphycenes and their metal complexes are reported, based on retro‐Diels–Alder reactions of the corresponding bicyclo[2.2.2]octadiene‐fused porphycenes, prepared by McMurray coupling of α,α′‐diformyldipyrrole. The photophysical and electrochemical properties are analyzed based on UV/Vis absorption, magnetic circular dichroism (MCD), and fluorescence emission, lifetime and quantum yield measurements, cyclic and differential pulse voltammetry (CV and DPV) and time‐dependent DFT calculations based on B3LYP geometry optimizations. Benzoporphycenes are found to be prime candidates for future use in photodynamic therapy.     

Synthesis, Characterization, DNA-binding Properties and DNA Cleavage of a New Ternary Copper(Ⅱ) Complex with Mixed-ligands of Tridentate Schiff Base and 1,10-Phenanthroline

A new copper(II) complex, [Cu(naph‐leu)phen]CH₃OH·0.5H₂O, in which naph‐leu is the tridentate Schiff base ligand derived from the condensation of 2‐hydroxy‐1‐naphthaldehyde and L‐leucine, phen is phenanthroline, has been synthesized and characterized by elemental analyses, IR spectra and single crystal X‐ray diffraction. The DNA‐binding properties of this complex have been investigated by absorption spectra, fluorescence spectra and circular dichroism (CD) spectra, as well as viscosity measurement. Results show that this copper(II) complex binds to calf thymus DNA (CT‐DNA) in an intercalative mode and its intrinsic binding constant K_b is 4.87×10³ L·mol^?1. Furthermore, the DNA cleavage activity of this copper(II) complex has also been investigated by submarine gel electrophoresis. Interestingly, it was found that this complex can cleave the supercoiled plasmid pBR322 DNA to both nicked and linear forms.     

Spectroscopic studies,structural characterization and electrochemical studies of two cobalt (III) complexes with tridentate hydrazone Schiff base ligands: Evaluation of antibacterial activities,DNA‐binding,BSA interaction and molecular docking

Co(III) complexes of tridentate Schiff base ligands derived from N‐(2‐hydroxybenzylideneamino)benzamide (H ₂ L ¹ ) and 2‐(2‐hydroxybenzylidene)hydrazine‐1‐carboxamide ( H ₂ L ² ) were synthesized and characterized using IR, Raman, ¹H–NMR and UV–Vis spectroscopies. X‐ray single crystal structures of complexes 1 and 2 have also been determined, and it was indicated that these Co(III) complexes are in a distorted octahedral geometry. The cyclic voltammetry (CV) of the complexes indicates an irreversible redox behavior for both complexes 1 and 2 . The antibacterial effects of the synthesized compounds have been tested by minimum inhibitory concentration and minimum bactericidal concentration methods, which suggested that the metal complexes exhibit better antibacterial effects than the ligands against Gram‐positive bacteria. The effects of the drug (drug  =  ligands and complexes) on bovine serum albumin (BSA) were examined using circular dichroism (CD) spectropolarimetry, and it was revealed that the BSA (BSA, as a carrier protein) secondary structure changed in the presence of the drug. Interaction of the drug with calf‐thymus DNA (CT‐DNA) was investigated by UV–Vis absorption, fluorescence emission, CV and CD spectroscopy. Binding constants were determined using UV–Vis absorption. The results indicated that the studied Schiff bases bind to DNA, with the hyperchromic effect and non‐intercalative mode in which the metal complexes are more effective than ligands. Furthermore, molecular docking simulation was used to obtain the energetic and binding sites for the interaction of the complexes with Mycobacterium tuberculosis enoyl‐acyl carrier protein reductase (InhA), and results showed that complex 1 has more binding energy.     

三齿多吡啶钴(Ⅱ)配合物的合成、表征及其与DNA的相互作用研究

合成了两种三齿多吡啶钴(Ⅱ)配合物[Co(DMPhTPY)2]2+(ClO-4)2(A)和[Co(H2Bzimpy)2]Cl2(B),用元素分析、IR对配合物的组成和结构进行了表征,测定了配合物A的晶体结构.用电子吸收光谱、荧光光谱、循环伏安法及凝胶电泳实验等方法研究了配合物与DNA的相互作用.结果表明配合物A和B与小牛胸腺(CTDNA)的作用属部分插入和静电结合,凝胶电泳实验表明配合物A在310nm光辐射15min,可使超螺旋pBR322DNA断裂为开环缺口型和线型DNA.     

Optical,Electrochemical, and Magnetic Properties of Pyrrole‐ and Thiophene‐Bridged 5,15‐Diazaporphyrin Dimers

The first examples of pyrrole‐ and thiophene‐bridged 5,15‐diazaporphyrin (DAP) dimers are prepared through Stille coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl) with the respective 2,5‐bis(tributylstannyl)heteroles. The effects of the heterole spacers and meso nitrogen atoms on the optical, electrochemical, and magnetic properties of the DAP dimers are investigated by UV/Vis absorption spectroscopy, density functional theory calculations, magnetic circular dichroism spectroscopy, cyclic voltammetry, and EPR spectroscopy. The heterole spacers are found to have a significant impact on the electronic transitions over the entire π‐system. In particular, the pyrrole‐bridged DAP dimers exhibit high light‐harvesting potential in the low‐energy visible/near‐infrared region owing to the intrinsic charge‐transfer character of the lowest excitation.     

Role of Knoevenagel condensate pyrazolone derivative Schiff base ligated transition metal complexes in biological assay and cytotoxic efficacy

A new bioessential Knoevenagel condensate Schiff base ligand (L) was synthesized by the reaction of 3‐(4‐hydroxy‐3‐methoxybenzyl)pentane‐2,4‐dione and 4‐aminoantipyrine. The ligand forms monomeric divalent transition metal complexes ( 1 – 4 ) which were characterized using spectral and analytical data. All these complexes have the general formula [ML]Cl₂, where M = Co(II), Ni(II), Cu(II) and Zn(II). They are electrolytic in nature and adopt square planar geometry. The binding propensity of these complexes with calf thymus DNA was investigated using absorption spectrophotometric titration, cyclic voltammetry and viscosity measurements. The binding constant values imply that the complexes bind with DNA via intercalation mode. The in vitro antibacterial and antifungal activities reveal that the complexes have good antimicrobial efficacy against a set of pathogens. The nucleolytic cleavage activity of these complexes on pUC18 DNA was investigated using agarose gel electrophoresis. Also, the in vitro cytotoxicity of the synthesized complexes against a panel of human tumour cell lines (MCF‐7 and HeLa) and normal cell lines (NHDF and HEK) was assayed using the MTT method. Interestingly, complex 1 exhibits more potent anticancer activity than cisplatin and other complexes.     

Nuclease activity of copper(II) complex containing 1,10-phenanthroline-5,6-dione and L-phenylalanine ligands

The interaction between CT-DNA and a ternary copper (II) complex, [Cu(phendio)(L-Phe)(H₂O)](ClO₄)·H₂O (CuPP, phendio = 1,10-phenanthroline-5,6-dione, L-Phe = L-phenylalanine), has been conducted by electronic spectra, fluorescence spectroscopy and cyclic voltammetry. It has been found that the max. absorption peak from the electronic spectra is red shifted and the intensity is weakened and that the values of peak current from cyclic voltammetry are decreased significantly in the presence of DNA compared with that in the absence of DNA. At the same time, the complex can quench the emission intensity of EB-DNA system. The existence of the intercalation mode between the complex and DNA was proven. By submarine gel electrophoresis, we found that the copper(II) complex can cleave circular plasmid pBR322 DNA into nicked and linear forms in the presence of ascorbic acid and H₂O₂. __________ Translated from Acta Scientiarum Naturalium Universitatis Nankaiensis, 2007, 40(1): 32–36 [译自: 南开大学学报(自然科学版)]