Synthesis, crystal structure, DNA/bovine serum albumin binding and antitumor activity of two transition metal complexes with 4-acylpyrazolone derivative

Two new complexes, namely [Cu6L6] (1) and [Zn(HL)(2)] (2) (H2L = N-(1-phenyl-3-methyl-4-propenylidene-5-pyrazolone)-2-furancarboxylic acid hydrazide), have been synthesized and characterized. Single crystal X-ray analysis indicates that complex 1 has a hexanuclear structure and complex 2 exhibits a mononuclear structure. The DNA/bovine serum albumin (BSA) binding properties of complexes 1 and 2 were investigated by absorption spectroscopy and fluorescence quenching. Both complexes could effectively intercalate to DNA with calculated quenching constants of 2.6 x 10(5) and 1.25 x 10(5) M-1, respectively. The quenching mechanism of the intrinsic fluorescence of BSA by the complexes was found to be a static one. The cytotoxicities of 1 and 2 were investigated in two human tumor cell lines, human esophageal cancer cells (Eca-109) and cervical cancer cells (HeLa). Complex 1 exhibits higher antitumor activity than 2. Furthermore, 1 can inhibit HeLa cells by inducing apoptosis and G0/G1 phase cell cycle arrest. All results demonstrate that 1 and 2 both have DNA/BSA binding capacity and antitumor activity.