Synthesis, Crystal Structural and Anticancer Evaluation of Two Novel Zn/Cd Complexes based on Carbonamidophosphate Ligand

Two novel metal complexes, Zn(CAPHPD) 3 (C 5 H 10 NH + ) and Cd(CAPHPD) 2 ·2H 2 O were prepared by simple solvent evaporation method, named as complexes 1 and 2 respectively. The physicochemical properties were systematically characterized. Single crystal X-ray diffraction patterns show that the two complexes crystallize in Monoclinic and Triclinic systems with trigonal bipyramidal and octahedral configurations, respectively. Activity experiments demonstrated that the complex exhibited lower cytotoxicity to normal NIH/3T3 cells and enhanced toxicity to 4T1 breast cancer cells compared to the ligand. IC 50 showed that coordination of Zn 2+ or Cd 2+ significantly reduced the toxic effect of the ligand on non-cancerous cells, while substantially enhancing its anticancer activity. The results of FITC/PI double staining showed that the ligand and complex 2 could induce cell death in both 4T1 and A549 cells, while complex 1 could specifically promote late apoptosis. The ROS level was further detected by DCFH-DA fluorescence probe method, and it was found that the ROS content in 4T1 cells treated with ligand was significantly lower than complex 1 and complex 2. This result is consistent with the data from the double-staining experiment, indicating that the ROS-dependent apoptosis pathway plays a key role in the anticancer mechanism of the complex.