Study on Schiff base complexes–cellular DNA interactions by a novel system of Hadamard transform fluorescence image microscopy
A novel system of Hadamard transform microscopic fluorescence imaging for single cells is presented, based on which the DNA ploidy of rat hepatocyte was quantitatively measured. The result shows that diploid rat hepatocyte has a stable DNA content, thus diploid rat hepatocyte was used to investigate the binding of five clinical anticancer agents, vincristine, cyclophosphamide, nitrogen mustard, cis-diamminedichloroplatinum(II) (CDDP) and mitomycin-C, with cellular DNA when acridine orange (AO) was used as the competitive fluorescence probe. Based on this model, some Schiff base complexes–cellular DNA interactions were investigated. The results indicate that all the twenty-two compounds, including Schiff base ligands of N-2-hydroxy-naphthaldehyde with D-glucoamine (NG) and the complexes of 3d-transitional metals ions with NG and with D-glucoamine (Glu) and the mixed complexes of NG and Glu series with α-glycine (GNG), have the ability to enter the cell membrane and interact with cellular DNA. Four of the compounds, CuGlu, Fe(II)NG, Fe(III)NG and CuGluG can intercalate with DNA like AO does and depress AO–DNA fluorescence to 70% or lower. An in intro UV-visible spectroscopic study on the compound–DNA spectra testified the above results and suggests that diverse interaction mechanisms coexist for all these complexes except intercalating mode. This study presents a new in vitro method for initial screening of anticancer compounds.