Copper(ii) complexes with 2NO and 3N donor ligands: synthesis, structures and chemical nuclease and anticancer activities
作者:Chandrasekaran Rajarajeswari、Rangasamy Loganathan、Mallayan Palaniandavar、Eringathodi Suresh、Anvarbatcha Riyasdeen、Mohamad Abdulkadhar Akbarsha
DOI:10.1039/c3dt32992e
日期:——
A series of water soluble copper(II) complexes of the types [Cu(L)Cl] 1–2, where LH is 2-(2-(1H-benzimidazol-2-yl)ethyliminomethyl)phenol (H(L1)), and 2-(2-(1H-benzimidazol-2-yl)-ethyliminomethyl)-4-methylphenol (H(L2)), and [Cu(L)Cl2] 3–6, where L is (2-pyridin-2-yl-ethyl)pyridin-2-ylmethyleneamine (L3), 2-(1H-benzimidazol-2-yl)ethylpyridin-2-yl-methyleneamine (L4), 2-(1H-benzimidazol-2-yl)ethyl(1H-imidazol-2-ylmethylene)amine (L5), and 2-(1H-benzimidazol-2-yl)ethyl-(4,4a-dihydroquinolin-2-ylmethylene)amine (L6), have been isolated and characterized by elemental analysis, electronic absorption, ESI-MS and EPR spectral techniques and the electrochemical method. The single crystal X-ray structures of [Cu(L1)Cl] 1 and [Cu(L2)Cl] 2 possess a distorted square-based coordination geometry while [Cu(L4)Cl2] 4 and [Cu(L6)Cl2] 6 possess a distorted trigonal bipyramidal coordination geometry. Both absorption spectral titration and an EthBr displacement assay reveal that all the complexes bind with calf thymus (CT) DNA through covalent mode of DNA interaction involving the replacement of an easily removable chloride ion with DNA nucleobases. All the complexes exhibit oxidative cleavage of supercoiled (SC) plasmid DNA in the presence of hydrogen peroxide as an activator. It is remarkable that at 50 μM concentration 5 and 6 completely degrade SC DNA into undetectable minor fragments and thus they act as efficient chemical nucleases. All the complexes are remarkable in displaying cytotoxicity against the HBL-100 human breast cancer cell line with potency more than that of the widely used drug cisplatin and hence they have the potential to act as promising anticancer drugs. Interestingly, they are non-toxic to normal cell lymphocytes isolated from human blood samples, revealing that they are selective in killing only the cancer cells.
一系列[Cu(L)Cl] 1-2 型水溶性铜(II)络合物,其中 LH 为 2-(2-(1H-苯并咪唑-2-基)乙基亚氨基甲基)苯酚 (H(L1))、和 2-(2-(1H-苯并咪唑-2-基)乙基亚氨基甲基)-4-甲基苯酚 (H(L2)),以及 [Cu(L)Cl2] 3-6,其中 L 是 (2-吡啶-2-基-乙基)吡啶-2-基亚甲基胺 (L3)、2-(1H-苯并咪唑-2-基)乙基吡啶-2-基亚甲基胺(L4)、2-(1H-苯并咪唑-2-基)乙基(1H-咪唑-2-基亚甲基)胺(L5)和 2-(1H-苯并咪唑-2-基)乙基-(4、L6),并通过元素分析、电子吸收、ESI-MS 和 EPR 光谱技术以及电化学方法对其进行了表征。[Cu(L1)Cl]1和[Cu(L2)Cl]2的单晶X射线结构具有扭曲的正方形配位几何,而[Cu(L4)Cl2]4和[Cu(L6)Cl2]6则具有扭曲的三叉双锥配位几何。吸收光谱滴定法和 EthBr 置换测定法都表明,所有配合物都是通过共价 DNA 作用模式与小牛胸腺 DNA 结合的,其中涉及将易于移除的氯离子与 DNA 核碱基置换。在过氧化氢作为激活剂的情况下,所有复合物都能氧化切割超卷曲(SC)质粒 DNA。值得注意的是,在 50 μM 浓度下,5 号和 6 号复合物能将 SC DNA 完全降解为检测不到的小片段,因此它们是高效的化学核酸酶。所有复合物对 HBL-100 人类乳腺癌细胞系都具有显著的细胞毒性,其效力超过了广泛使用的顺铂,因此它们有可能成为有前途的抗癌药物。有趣的是,它们对从人体血液样本中分离出来的正常细胞淋巴细胞没有毒性,这表明它们只选择性地杀死癌细胞。