Interaction with biomacromolecules and antiproliferative activities of Mn(II), Ni(II), Zn(II) complexes of demethylcantharate and 2,2′-bipyridine

• Three new complexes of demethylcantharate and 2,2-bipyridine were synthesized.
• Their structures were determined by X-ray diffraction.
• The complexes bound DNA moderately via partial intercalation modes.
• They have intense interaction with BSA through static quenching.
• The Zn(II) complex has strongest activities against the two tested cancer cell lines.

Three new transition metal complexes [Mn2(DCA)2(bipy)2]·5H2O (1), [M2(DCA)2(bipy)2(H2O)]·10H2O(M = Ni(II)(2);Zn(II)(3)), (DCA = demethylcantharate, 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylate, C8H8O5) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra and X-ray diffraction techniques. Each metal ion was six-coordinated in complexes. Complex 1 has a Mn2O2 center. Complexes 2 and 3 have asymmetric binuclear structure. Great amount of intermolecular hydrogen–bonding and π–π* stacking interactions were formed in these complex structures. The DNA-binding properties of complexes were investigated by electronic absorption spectra and viscosity measurements. The DNA binding constants Kb/(L mol−1) were 1.71 × 104 (1), 2.62 × 104 (2) and 1.59 × 104 (3) at 298 K. The complexes could quench the intrinsic fluorescence of bovine serum albumin (BSA) strongly through static quenching. The protein binding constants Ka/(L mol−1) were 7.27 × 104 (1), 4.55 × 104 (2) and 7.87 × 104 L mol−1 (3) and binding site was one. The complexes bind more tightly with DNA and BSA than with ligands. Complexes 1 and 3 had stronger inhibition ratios than Na2(DCA) against human hepatoma cells (SMMC-7721) lines and human gastric cancer cells (MGC80-3) lines in vitro. Complex 3 showed the strongest antiproliferative activity against SMMC-7721 (IC50 = 29.46 ± 2.12 μmol L−1) and MGC80-3 (IC50 = 27.02 ± 2.38 μmol L−1), which shows potential in anti-cancer drug development.

Three new Mn(II), Ni(II), Zn(II) complexes of demethylcantharate and 2,2-bipyridine were designed and synthesized. The interactions of complexes with DNA and bovine serum albumin (BSA) were studied. The antiproliferative activities against human hepatoma cells (SMMC-7721) and human gastric cancer cells (MGC80-3) were tested in vitro.Figure optionsDownload as PowerPoint slide