Nagaraj Karuppiah, Velmurugan Gunasekaran, Sakthinathan Subramanian, Venuvanalingam Ponnambalam, Arunachalam Sankaralingam
School of Chemistry, Bharathidasan University, Tiruchirappalli-620 024, India.
Dalton Trans. 2014 Dec 28;43(48):18074-86. doi: 10.1039/c4dt02134g. Epub 2014 Oct 29.
A new class of surfactant Co(III) complexes, cis-Co(ip)2(C12H25NH2)23 (1) and cis-Co(dpq)2(C12H25NH2)23 (2) (ip = imidazo[4,5-f][1,10]phenanthroline, dpq = dipyrido[3,2-d:2'-3'-f]quinoxaline), have been synthesized and characterized by various spectroscopic and physico-chemical techniques. The critical micelle concentration (CMC) values of these complexes in aqueous solution were obtained from conductance measurements. The specific conductivity data (at 303, 308, 313, 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0)(m), ΔH(0)(m) and ΔS(0)(m)). The trend in DNA-binding affinities and the spectral properties of a series of complexes, cis-Co(ip)2(C12H25NH2)23 (1) and cis-Co(dpq)2(C12H25NH2)23 (2), have been experimentally and theoretically investigated. The experimental results indicate that the size and shape of the intercalated ligand and hydrophobicity of the complexes have a marked effect on the binding affinity of the complexes to CT DNA in intercalation mode, and the order of their intrinsic DNA-binding constants Kb is Kb(1) < Kb(2). In addition, the influence of the extended aromatic ring and optical properties of the complexes can be reasonably explained by applying the DFT calculations. The energy gap between HOMO and LUMO indicates that these complexes are prone to interact with CT DNA. Further, molecular docking calculations have also been performed to understand the nature of binding of the complexes and the result confirms that the complexes interact with CT DNA through the alkyl chain. The cytotoxic activity of these complexes on human liver carcinoma cancer cells were determined adopting MTT assay and specific staining techniques, which revealed that the viability of the cells thus treated was significantly decreased and the cells succumbed to apoptosis as seen in the changes in the nuclear morphology and cytoplasmic features.
合成了一类新型的表面活性剂钴（III）配合物，即顺式-Co(ip)₂(C₁₂H₂₅NH₂)₂₃（1）和顺式-Co(dpq)₂(C₁₂H₂₅NH₂)₂₃（2）（ip = 咪唑并[4,5-f][1,10]菲咯啉，dpq = 二吡啶并[3,2-d:2'-3'-f]喹喔啉），并通过各种光谱和物理化学技术对其进行了表征。通过电导测量获得了这些配合物在水溶液中的临界胶束浓度（CMC）值。比电导率数据（在303、308、313、318和323 K）用于评估温度依赖性CMC和胶束化的热力学（ΔG(0)(m)、ΔH(0)(m)和ΔS(0)(m)）。通过实验和理论研究了一系列配合物顺式-Co(ip)₂(C₁₂H₂₅NH₂)₂₃（1）和顺式-Co(dpq)₂(C₁₂H₂₅NH₂)₂₃（2）的DNA结合亲和力趋势和光谱性质。实验结果表明，插入配体的大小和形状以及配合物的疏水性对配合物以插入模式与CT DNA的结合亲和力有显著影响，其固有DNA结合常数Kb的顺序为Kb(1) < Kb(2)。此外，通过应用DFT计算可以合理地解释配合物的扩展芳香环和光学性质的影响。HOMO和LUMO之间的能隙表明这些配合物易于与CT DNA相互作用。此外，还进行了分子对接计算以了解配合物的结合性质，结果证实配合物通过烷基链与CT DNA相互作用。采用MTT法和特异性染色技术测定了这些配合物对人肝癌细胞的细胞毒性活性，结果表明，如此处理的细胞活力显著降低，并且细胞因核形态和细胞质特征的变化而发生凋亡。
