Studies On Interactions Of Carbazole Derivatives With DNA,cell Image,and Cell Viability

In this study,we synthesized two novel carbazole derivatives（1 and 2）,and used a variety of methods to study interactions of carbazole derivatives with DNA,cell image,and cell-viability.The main results are as follows:（1）The target compounds 1 and 2 were obtained using9-Ethyl-9H-carbazole-3-carbaldehyde through one and two steps of reactions,respectively.The final products were fully characterized by ¹H NMR,¹³CNMR,and high resolution mass spectrometry.（2）UV–vis absorption titration and FID experiments showed that 1 and2 were bound preferentially to G-quadruplex DNA over duplex and i-motif,and the binding affinities of 1 to all the DNA were higher than those of 2;Job Plot assays indicated that the binding stoichiometries of the compound/G-quadruplex complexes were all near 2 except the compound/bcl-2 complexes with a binding stoichiometry of 1.5,and the binding stoichiometry of the 1/i-motif complexes was 2 while it was unascertainable for the 1/i-motif complex;CD experiments indicated that both 1 and 2 had no influence on the conformation of DNA;both fluorescence titration and fluorescence lifetime measurements indicated that1 and 2 could interact with DNA,and 1 was suitable for using as a duplex fluorescent probe,on the contrary,2 possessed a potential for G-quadruplex fluorescent probe.（3）MTT and cell morphology assays indicated that 1 and 2 could inhibit the proliferation of HepG2 cells and the inhibitory effect of 1 was higher than that of 2;confocal fluorescence imaging and DNase and RNase digest tests showed that the main targets of 1 in living cells were double-stranded and/or G-quadruplex DNA while the potential target of 2 was RNA.