Synthesis, crystal structure and biological activity of two Mn complexes with 4-acyl pyrazolone derivatives

•Two Mn complexes of mononuclear and dinuclear were obtained.•The interaction of the complex with DNA should be intercalation.•The protein binding studies confirmed the interactions of the complexes with bovine serum albumin (BSA).•The complexes possess good anticancer activity.•Complex 1 inhibit cancer cell's growth by inducing apoptosis.

In order to study the biological activities of transitional metal complexes based on 4-acyl pyrazolone derivatives, two Mn complexes [Mn(HLa)(La)]·(CH3CN)1.5·H2O (1) and [Mn2(Lb)2(μ-EtO)2(EtOH)2] (2) (H2La = N-(1-phenyl-3-methyl-4-benzoyl-5-pyrazolone)-2-thiophenecarboxylic acid hydrazide, H2Lb = N-(1-phenyl-3-methyl-4-propenylidene-5-pyrazolone)-2-thiophenecarboxylic acid hydrazide) have been synthesized and characterized. Single crystal X-ray diffraction analysis indicated that 1 is a mononuclear complex and 2 exhibits a dinuclear centrosymmetric structure. Binding of the complexes with Herring Sperm DNA (HS-DNA) showed that complexes 1 and 2 could intercalate to DNA with quenching constant of 5.3 × 104 M−1 and 4.9 × 104 M−1, respectively. The interactions of the complexes with bovine serum albumin (BSA) indicated that complexes 1 and 2 could quench the intrinsic fluorescence of BSA in a static quenching process. Further, the inhibitory effects of the complexes on the cell population growth of the human esophageal cancer Eca-109 cells and the cervical cancer HeLa cells were determined by MTT assay, which indicated that both 1 and 2 significantly inhibited the growth of Eca-109 and HeLa cells, the inhibitory activity of complex 1 is stronger than that of 2. We further observed that complex 1 inhibited the growth of HeLa cells through inducing the apoptosis and arresting cell cycle at S phase. Our results suggested that both complexes 1 and 2 have DNA- and protein-binding capacity and antitumor activity.

Graphical abstractTwo Mn complexes of 4-acyl pyrazolone derivatives with different structures were constructed and characterized. The DNA binding, protein binding, the inhibitory effects on two cancer cells of complexes 1 and 2 and the apoptosis assay of complex 1 were also investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide