Cu(II) and Zn(II) complexes with Schiff bases derived from diethylenetriamine, [Cu(C22H23N5)(H2O)(ClO4)2] (1), [Cu(C14H18N4)(ClO4)](ClO4) (2), and [Zn(C10H17N5Cl)]4[ZnCl4]2·H2O (3), have been synthesized and structurally characterized. The interactions of the complexes with CT-DNA were investigated by electronic absorption, circular dichroism (CD), and fluorescence spectroscopies. All three complexes appear to bind to DNA via groove binding modes. The order of DNA binding strength was 2 > 1 > 3. The complexes proved to be capable of efficient cleavage of pBR322 DNA at micromolar concentrations in the presence of ascorbic acid as a reducing regent. The hydroxyl radical may be the reactive species, and H2O2 may be involved in DNA strand breakage induced by these complexes. Furthermore, in vitro cytotoxicities of the complexes against four human carcinoma cell lines (HepG2, MGC-803, EC9706, and MCF-7) were screened by MTT assays. Complex 2 shows potent activity against HepG2 and MGC-803 cell lines; for all four cell lines, the activities of the complexes follow the order: 2 > 1 > 3. Hence, the different anticancer activities of the complexes may be correlated with their DNA binding abilities.

中文翻译：

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基于二亚乙基三胺的三种席夫碱复合物：合成、结构、DNA结合和裂解以及体外细胞毒性

Cu(II) 和 Zn(II) 与衍生自二亚乙基三胺的席夫碱络合物，[Cu(C22H23N5)(H2O)(ClO4)2] (1)，[Cu(C14H18N4)(ClO4)](ClO4) (2)，和[Zn(C10H17N5Cl)]4[ZnCl4]2·H2O(3)，已经合成并进行了结构表征。通过电子吸收、圆二色性 (CD) 和荧光光谱研究复合物与 CT-DNA 的相互作用。所有三种复合物似乎都通过凹槽结合模式与 DNA 结合。DNA 结合强度的顺序是 2 > 1 > 3。证明在抗坏血酸作为还原剂存在的情况下，复合物能够有效切割微摩尔浓度的 pBR322 DNA。羟基自由基可能是反应性物质，H2O2 可能参与这些复合物诱导的 DNA 链断裂。此外，通过 MTT 测定筛选复合物对四种人癌细胞系（HepG2、MGC-803、EC9706 和 MCF-7）的体外细胞毒性。复合物 2 显示出对 HepG2 和 MGC-803 细胞系的有效活性；对于所有四种细胞系，复合物的活性顺序为：2>1>3。因此，复合物的不同抗癌活性可能与其DNA结合能力相关。