Substituent effects on cytotoxic activity, spectroscopic property and DNA binding property of naphthalimide derivatives.

A series of novel naphthalimide derivatives NI1-5 containing piperazine moieties (N-(2-hydroxyethyl)piperazine and 1-piperazinepropanol) and piperidine moieties (4-piperidinemethanol, 4-hydroxypiperidine and 4-piperidineethanol) have been synthesized and evaluated for their cytotoxic activity, spectroscopic property, and DNA binding behaviors. It was found that substituents at the 4-position remarkably influence the various activities of this series of compound. Compounds NI3-5 modified with piperidines exhibited potent cytotoxic activities against Hela, SGC-7901, and A549 cells with the IC50 values from 0.73 m to 6.80 m, which are better than NI1-2 functionalized with piperazines. Compounds NI1-2 showed higher binding capacity with Ct-DNA than compounds NI3-5 based on studies of UV-vis, fluorescence and CD spectra. Furthermore, compounds NI3-5, as DNA intercalators, showed fluorescence enhancement upon binding with Ct-DNA. More interestingly, fluorescence imaging studies of compound NI4 with A549 cells showed that the fluorescence predominantly appeared in the cytoplasm. These results provided a potential application of NI3-5 as anticancer therapeutic and cancer cell imaging agents.