Nickel–quinolones interaction. Part 2 – Interaction of nickel(II) with the antibacterial drug oxolinic acid

Nickel–quinolones interactionPart 3 — Nickel(II) complexes of the antibacterial drug flumequine

“…The values of the ratio 10Dq/B (=10. 2-10.9) are within the range expected for octahedral Ni 2+ complexes [20,21]. Additionally, an absorption band assigned to the ligand-tometal charge transfer transition for the quinolone ligand [19][20][21]45,46] appears at around 400 nm.…”

“…In the visible region, three lowintensity bands are observed in the region 750-765 nm (band I), 640-652 nm (band II) and 450-455 nm (band III) nm assigned to d-d transitions, typical for distorted octahedral Ni 2+ complexes [3,20,21]. For octahedral local symmetry, band I can be attributed to a 3 A 2g → 3 T 2g transition, band II to a 3 A 2g → 3 T 1g transition and band III to a 3 A 2g → 3 T 1g (P) transition.…”

“…A principal target of metals in the cancer cells is the coordination with DNA, bound selectively to it through the oxygen of phosphates and/or to heterocyclic nitrogen atoms of DNA bases [17,18]. Therefore, the interaction of Ni(II) complexes with DNA has been mainly dependent on the structure of the ligand exhibiting intercalative behavior [18][19][20][21][22][23] and/or DNA cleavage ability [24,25].…”

“…Taking into consideration that metal complexes with drugs may exhibit more pronounced biological properties in comparison to the free drugs, we have initiated the study of nickel(II) complexes containing quinolone antimicrobial agents [19][20][21]. In this context, we report the synthesis, the structural characterization, the electrochemical and the biological properties of the neutral mononuclear nickel(II) complexes with the first-generation quinolone antibacterial drug flumequine with or without nitrogen donor heterocyclic ligand such as 4-benzylpyridine (4bzpy), pyridine (py), 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) [Ni(flmq) 2 (4bzpy) 2 2 ], 1.…”

Variation in the biomolecular interactions of nickel(ii) hydrazone complexes upon tuning the hydrazide fragment

“…Many therapeutic agents, particularly anticancer drugs, are known to bind DNA via either of these motifs and the possibility of gene modulation by specific sequence binding of small molecules to DNA has also been explored. The interaction of Ni(II) complexes with DNA has been mainly dependent on the structure of the ligand exhibiting intercalative behavior [19][20][21][22][23] and/or DNA cleavage ability. 24,25 Serum albumin is the major soluble protein constituent in the circulatory system of a wide variety of organisms and it has the ability to reversibly bind to a large variety of endogenous and exogenous ligands such as fatty acids, drugs, and metal ions in the bloodstream.…”