DNA-binding properties and antioxidant activity of lanthanide complexes with the Schiff base derived from 3-carbaldehyde chromone and isonicotinyl hydrazine

Structural analyses indicate that the ligand and lanthanide ions form mononuclear 10-coordinate ([Ln L₂ · (NO₃)₂] · NO₃ [Ln(III) = La, Sm, Nd, and Yb; L is chromone-3-carbaldehyde-(isonicotinoyl) hydrazone) complexes with 1 : 2 metal-to-ligand stoichiometry. DNA-binding studies show that the ligand and its lanthanide complexes can bind to calf thymus DNA via an intercalation mode with binding constants of 10⁵ (mol L^?1)^?1, and the lanthanide complexes bind stronger than the free ligand alone. Antioxidant activities of the ligand and lanthanide complexes were determined by superoxide and hydroxyl radical scavenging methods in vitro. The ligand and complexes possess strong scavenging effects, and the lanthanide complexes show stronger antioxidant activities than the ligand and some standard antioxidants, such as vitamin C.     

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl) benzylamine with its cobalt(II) complex: synthesis,crystal structure,DNA-binding properties,and antioxidant activity

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl)benzylamine (bmbb) and its cobalt complex, [Co(bmbb)₂](pic)₂ (pic?=?picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray revealed that the coordination sphere around Co(II) is distorted octahedral with an N₆ ligand set from two tridentate bmbb. The DNA-binding properties of bmbb and the Co(II) complex were investigated by spectrophotometric and viscosity measurements. The results suggest that bmbb and Co(II) complex both bind to DNA via intercalation, and the Co(II) complex binds to DNA more strongly than bmbb. The Co(II) complex also exhibited potential antioxidant properties in vitro studies.     

Synthesis,characterization and DNA-binding properties of Ru(II) complexes coordinated by ofloxacin as potential antitumor agents

Three Ru complexes coordinated by oxfloxacin, [Ru(L)₂(OFX)]Cl·2H₂O (L = bpy, 1; dmbpy, 2; phen, 3; and OFX = ofloxacin), were synthesized and characterized. These complexes can inhibit the growth of cervical cancer HeLa cells efficiently. Furthermore, these three complexes exhibited excellent binding affinities with DNA, as confirmed by spectroscopy methods and viscosity experiments. Therefore, the synthesized Ru(II) complexes have excellent DNA-binding abilities with potential applications in cancer chemotherapy.     

Synthesis,characterization, photocleavage,antimicrobial activity and DNA binding of [Co(bpy)2MHPIP]3+, [Co(dmb)2MHPIP]3+, and [Co(phen)2MHPIP]3+ complexes

4-Methyl-2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) (MHPIP) and its complexes [Co(bpy)₂MHPIP]³⁺ (1) (bpy = 2,2′-bipyridine), [Co(dmb)₂MHPIP]³⁺ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)₂MHPIP]³⁺ (3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA, ¹H, ¹³C-NMR, and mass spectra. The binding of the three complexes with calf-thymus-DNA (CT-DNA) has been investigated by absorption and emission spectroscopy, DNA-melting techniques, viscosity measurements, and DNA cleavage assay. The spectroscopic data and viscosity results indicate that these complexes bind to CT-DNA via an intercalative mode. The complexes also promote photocleavage of plasmid pBR322 DNA and were screened for antimicrobial activity.     

Biological evaluation of redox stable cisplatin/Cu(II)-DNA adducts as potential anticancer agents

A series of non-enolizable β-diketonate-based copper(II) complexes with LCuCl₂ [L = Knoevenagel condensates of curcumin (Salcimine) and methylacetoacetate (SalMaA)-based Schiff bases] chromospheres as functional models of chemotherapy drug cisplatin were investigated for their covalent interaction with herring sperm DNA. The synthesis and structural characterization of 1a and 1b have been reported in our previous article. However, their DNA interactions and cytotoxicity properties were not studied. These analyses have been carried out mainly through electrochemical techniques supplemented with spectral, relative viscosity, gel electrophoresis techniques, and AGS cancer cells using MTT assay. The cytotoxic activities of the ligand, curcumin-based copper complex, and cisplatin were tested against the AGS cancer cell line under similar experimental conditions showing that the complex exhibited cancer cell inhibitory rate closer to cisplatin even at low concentration. This was also seen in the docking of the Cu-complex onto a rich guanine B-DNA decamer, where a Cu–N3_(guanine) interaction instead of Pt-N7 as cisplatin is detected. The obtained results in this study prove that these complexes could be a promising substitute for cisplatin as a new family of non-platinum-based anticancer metallo-drugs after in vivo tests on animal models.     

Novel synthetic 9-benzyloxyacridine analogue as both tyrosine kinase and topoisomerase I inhibitor

Multi-target agents against tyrosine kinases and topoisomerases are potentially useful for the effective treatment of cancers.Discovery of new multi-target scaffolds are important for developing such agents. A series of five novel acridine analogues,LXL 1-5,were synthesized and their antiproliferative activity against HepC-2 cell lines were evaluated,among which the 9-benzyloxyacridine analogue,LXL-5, showed inhibitory activity against tyrosine kinases,VEGFR-2 and Src.The results of UV-visible absorption spectra and fluorescence emission spectra,as well as DNA topoisomerase I inhibition assay, indicated topoisomerase I inhibitory activity.Our study suggested that acridine scaffold,previously shown to have no multi-target kinase and topoisomerase inhibitory activity,might be potentially developed as a multi-target inhibitor of tyrosine kinases and topoisomerase I.     

Synthesis,DNA-binding,cytotoxicity, and cleavage studies of unsymmetrical oxovanadium complexes

An unsymmetrical oxovanadium complex [VO(SAA)(phen)] (1) (SAA?=?salicylidene anthranilic acid, phen?=?phenanthroline) and its derivative [VO(MOSAA)(phen)] (2) (MOSAA?=?2-hydroxy-4-methoxysalicylidene anthranilic) have been synthesized and characterized by elemental analysis, UV-Vis, ES-MS, IR, and ¹H NMR. The interaction of these two complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration, fluorescence spectra, viscosity measurements, and thermal denaturation. Their photocleavage reactions with pBR322 supercoiled plasmid DNA were investigated by gel electrophoresis. The cytotoxicity of these two complexes against myeloma cell (Ag8.653) and gliomas cell (U251) have been assessed by MTT assay. The results show that both 1 and 2 bind to CT-DNA in classical intercalation, and the DNA-binding affinity of 1 is larger than that of 2. These complexes enhance the oxidative cleavage of supercoiled pBR322 DNA and both complexes have cytotoxic activities against Ag8.653 and U251 cell lines. Complex 1 has more potent inhibitory effect against the two cell lines than 2.     

Synthesis and noncovalent DNA-binding properties of thiazole derivatives related to leinamycin

A series of compounds related to the macrocyclic portion of the DNA-damaging antitumor agent leinamycin were prepared as tools to characterize noncovalent DNA binding by this natural product. Acyclic (Z,E)-dienes were assembled via a Sonogashira coupling followed by partial hydrogenation. A Stille coupling was used in the cyclization step leading to a macrocyclic thiazole-diene analogue. Results obtained using the synthetic analogues reported here indicate that the extended π-system on the `left-hand side' of leinamycin is required for noncovalent association of the natural product with duplex DNA.     

由联苯-2,4,4',6-四甲酸构筑的三维镉配位聚合物的合成、结构及与DNA作用

在水热条件下,以联苯-2,4,4',6-四甲酸(C16H10O12,H4bptc)为主配体、1,3-二(4-吡啶基)-丙烷(bpp)为辅助配体,与氯化镉(CdCl₂·2.5H₂O)反应合成了2个三维镉配位聚合物{[Cd₂(bptc)(H₂O)₃]·H₂O}_n (1),{[Cd₂(bptc)(bpp)·H₂O]·2.25H₂O}_n (2)。用元素分析、红外光谱对配合物的组成及结构进行了表征,并通过X射线单晶衍射的方法测定了配合物的晶体结构。配合物1具有双核结构,2个中心离子Cd(Ⅱ)同为六配位,均形成略有畸变的八面体结构;而配合物2尽管也具有双核结构,但不同于1的是其中一个中心离子构成略显畸变的八面体几何结构,另一个却构成五角双锥结构。用溴化乙锭荧光光谱法测定了配体和配合物与DNA作用情况,结果表明配合物与DNA的作用强于配体。     

由4-甲基-1，2，3-噻二唑-5-甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以4-甲基-1,2,3-噻二唑-5-甲酸（C₄H₄N₂O₂S, HL）分别与硫酸钴（CoSO₄·7H₂O）、氯化铜（CuCl₂·2H₂O）、硝酸银（AgNO₃）反应合成了3个配合物[Co（L）₂（H₂O）₄] ·2H₂O （1）、[CuNa（L）₃] _n （2）和[AgL] _n （3）,用元素分析、红外光谱、热重分析进行表征,用单晶X射线衍射测定了产物的结构。配合物1属于三斜晶系,空间群P1,Co²⁺的配位数为6,形成一个略为拉长的CoN₂O₄八面体,与理想的正八面体非常接近。配合物2属于三斜晶系,空间群P1。Cu²⁺离子的配位数为4,构成变形的平面四边形结构,Na⁺离子的配位数为6,构成一个略微变形的八面体结构,最终形成三维网状结构。配合物3属于单斜晶系,空间群P2₁/c,银离子为三配位,构成变形的平面三角形构型,具有二维网状结构。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱。