Synthesis, characterization, DNA-binding and antiproliferative activity of Nd(III) complexes with N-(nitrogen heterocyclic) norcantharidin acylamide acid.

Three novel complexes [Nd(L)(NO3)(H2O)2].NO(3).2H2O (HL1 = N-pyrimidine norcantharidin acylamide acid, C12H13N3O4; HL2 = N-pyridine norcantharidin acylamide acid, C13H14N2O4; HL3 = N-phenyl norcantharidin acylamide acid, C14H15NO4) were synthesized. HL1, HL2 and HL3 are the ligand of complex(1), complex(2) and complex(3), respectively. Their structures were characterized by elemental analysis, conductivity measurement, infrared spectra and thermogravimetric analysis. The DNA-binding properties of the complexes have been investigated by fluorescence spectroscopy and viscosity measurements. The results suggest that the complexes can bind to DNA by partial intercalation. The liner Stern-Volmer quenching constant Ksq values are 3.3(+/-0.21)(1), 1.7(+/-0.19)(2) and 0.9(+/-0.04)(3), respectively. Complex (1) and (2) have been found to cleave pBR322 plasmid DNA at physiological pH and temperature. The test of antiproliferation activity indicates that complex(1) has strong antiproliferative ability against the SMMC7721 (IC50 = 131.7 +/- 23.4 micromol x L(-1)) and A549 (IC50 = 128.4 +/- 19.9 micromol x L(-1)) cell lines. The inhibition rates of complex(2) (IC50 = 86.3 +/- 11.3 micromol x L(-1)) are much higher than that of NCTD (IC50 = 115.5 +/- 9.5 micromol x L(-1)) and HL2 (111.0 +/- 5.7 micromol x L(-1)) against SMMC7721 cell lines.