The synthesis and characterisation of five bis-1,8-naphthalimide containing Tröger's bases 1–5 formed from their corresponding 3-amino-1,8-naphthalimide precursors 6–10 is described. The photophysical investigations of 1–5 and 6–10 were carried out in several organic solvents as well as in water and as a function of pH using UV-Vis absorption and fluorescence spectroscopies. The DNA binding affinities of 1–5 in aqueous solution at pH 7.4 were also investigated using several UV-Vis absorption and fluorescence experiments by using calf thymus DNA (ct-DNA). These molecules exhibited significant DNA binding affinities; where large binding values (Kb) in the range of 106 M−1 were determined, even in competitive media (50 mM and 160 mM NaCl at pH 7.4). Thermal denaturation measurements also showed that 1–5 significantly stabilised the DNA helix. Using linear and circular dichroism we further demonstrated that the DNA binding interaction occurs both by intercalation and by groove binding. The Tröger's bases were further shown to be rapidly taken up into cells using confocal fluorescence spectroscopy; and cytotoxic studies in HeLa and MCF-7 cells showed that most of the Tröger's bases were effective cytotoxic agents with EC50 values of between 1.1–12 μM and that all the active compounds induced programmed cell death by apoptosis, where up to 70% cellular death was observed after 24 h of incubation for 4.
描述了由相应的 3-
氨基-1,8-
萘二甲
酰亚胺前体 6-10 形成的含有 Tröger 碱 1-5 的五种双-1,8-
萘二甲
酰亚胺的合成和表征。使用紫外-可见吸收和荧光光谱,在几种有机溶剂和
水中进行了 1-5 和 6-10 的光物理研究,并作为 pH 的函数。还使用小牛胸腺 DNA (ct-DNA) 通过多次 UV-Vis 吸收和荧光实验研究了 1-5 在 pH 7.4
水溶液中的 DNA 结合亲和力。这些分子表现出显着的 DNA 结合亲和力;即使在竞争性介质(50 mM 和 160 mM NaCl,pH 7.4)中,也可以确定 106 M−1 范围内的大结合值 (Kb)。热变性测量还表明 1-5 显着稳定了 DNA 螺旋。使用线性和圆二色性,我们进一步证明DNA结合相互作用通过嵌入和凹槽结合发生。使用共焦荧光光谱进一步证明 Tröger 的碱基可以快速被细胞吸收; HeLa 和 MCF-7 细胞中的细胞毒性研究表明,大多数 Tröger 碱都是有效的细胞毒性剂,
EC50 值在 1.1–12 μM 之间,并且所有活性化合物均通过细胞凋亡诱导程序性
细胞死亡,其中高达 70% 的
细胞死亡4.培养24小时后观察。