Syntheses, structures, DNA-binding, cytotoxicity and apoptosis of manganese(II) and ferrous(II) complexes containing 4-sulfobenzoate anion with N,N-heterocyclic amines

Three new complexes, {[Mn(2,2'-bipy)(4,4'-bipy)(0.5)(4-sb)(H2O)](H2O)(2)}(n) (1), [Mn(phen)(2)(4-sb)(H2O)](4,4'-bipy)(0.5)(H2O)(3) (2), and [Fe-2(phen)(6)](4-Hsb)(H2O) 5 (3) [4-sb = 4-sulfobenzoate dianion, 2,2'-bipy = 2,2'-bipyridine, 4,4'-bipy = 4,4'-bipyridine, phen = 1,10-phenanthroline], have been synthesized and structurally characterized. The interaction of complex with HS-DNA was investigated by carrying out UV-vis absorption spectrum and fluorescence ethidium bromide displacement experiment. The DNA-binding constants K-b of complexes 1, 2, and 3 were calculated to be 7.39 x 10(5) M-1, 3.94 x 10(5) M-1, and 9.34 x 10(5) M-1, respectively. The results indicated that these complexes interact with HS-DNA through intercalative mode. Competitive studies with ethidium bromide (EB) further showed that the complexes bind to DNA probably via intercalation. The complexes were tested for antiproliferative activities on a panel of cell lines (MCF-7, HepG-2, A549, BGC823, and HTR-8) by MIT method, three complexes can inhibit the tumor cell proliferation, but complex 1 is less cytotoxic than other two complexes. The apoptosis assay was assessed with the Annexin-V/PI double staining methods and the results revealed that complexes induced the HepG-2 cells apoptosis. (C) 2020 Elsevier B.V. All rights reserved.