Antimicrobial Activity and DNA/BSA Binding Affinity of Polynuclear Silver(I) Complexes with 1,2-Bis(4-pyridyl)ethane/ethene as Bridging Ligands

Abstract

1,2-Bis(4-pyridyl)ethane (bpa) and 1,2-bis(4-pyridyl)ethene (bpe) were used for the synthesis of polynuclear silver(I) complexes, {[Ag(bpa)]NO 3 } n (1), {[Ag(bpa) 2 ]CF 3 SO 3 . H 2 O} n (2) and {[Ag(bpe)]CF 3 SO 3 } n (3). In complexes 1-3, the corresponding nitrogencontaining heterocycle acts as a bridging ligand between two Ag(I) ions. In vitro antimicrobial activity of these complexes, along with the ligands used for their synthesis, was evaluated against the broad panel of Gram-positive and Gram-negative bacteria and fungi. e silver(I) complexes 1-3 showed selectivity towards Candida spp. and Gram-negative Escherichia coli in comparison to the other investigated bacterial strains, effectively inhibiting the growth of four different Candida species with minimal inhibitory concentrations (MICs) between 2.5 and 25 μg/mL and the growth of E. coli, with MIC value being 12.5 μg/mL. Importantly, complex 2 significantly reduced C. albicans filamentation, an essential process for its pathogenesis. Antiproliferative effect on the normal human lung fibroblast cell line MRC-5 was also evaluated with the aim of determining the therapeutic potential of the complexes 1-3. e interactions of these complexes with calf thymus DNA (ctDNA) and bovine serum albumin (BSA) were studied to evaluate their binding activities towards these biomolecules for possible insights on their mode of action.

Structural Characterization, Antimicrobial Activity and BSA/DNA Binding Affinity of New Silver(I) Complexes with Thianthrene and 1,8-Naphthyridine

“…The values of K sv constants indicate that the Ag1 complex containing tia ligand has a higher affinity for BSA compared to the remaining two complexes Ag2 and Ag3 with 1,8-naph ligand. The K sv values for Ag2 and Ag3 are similar to those calculated for silver(I) complex with 1,2-bis(4-pyridyl)ethene [ 62 ], as well as for those with N -methyl-1,3,5-triaza-7-phosphaadamantane and tris(pyrazol-1-yl)methanesulfonate [ 63 ]. The K q constant depends on the probability of a collision between fluorophore and quencher and is a measure of the tryptophan residues exposure to the investigated compound [ 64 ].…”

“…For comparison, the percentage of hypochromism of 50% was previously obtained for lucigenin, which is proven as a DNA intercalator [ 72 ]. The values of K sv constants for the presently investigated complexes are slightly lower than those obtained for silver(I) complexes {[Ag(bpa)]NO 3 } n and {[Ag(bpa) 2 ]CF 3 SO 3 ·H 2 O} n , where bpa stands for 1,2-bis(4-pyridyl)ethane [ 62 ]. On the other hand, silver(I) complex [Ag(daf)(1,10-phen)]NO 3 (daf = 4,5-diazafluoren-9-one and 1,10-phen = 1,10-phenanthroline) had high affinity for the intercalation between DNA base pairs, what can be concluded from the value of its K sv constant of 0.97 × 10 5 M −1 at 37 °C [ 73 ].…”

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

“…Transition metal ions regarded as potential biological agents are platinum, cobalt, copper, zinc, and ruthenium [ 14 , 15 , 16 , 17 ]. However, there is an emerging curiosity in exploring silver(I) and its complexes as antimicrobial and antioxidant agents as well as efficient DNA and protein binders [ 18 ] with potential cytotoxicity activity. Our interest in silver(I) ion is due to its low toxicity to human at low concentration [ 19 ], high cytotoxicity [ 20 ], and good potency compared to other bioactive metal complexes such as cisplatin, known to have drawbacks which include nephrotoxicity, drug resistance, and cervical renal problems [ 21 ].…”

Synthesis, Characterization, Antimicrobial and DNA Binding Studies of a Tetradentate N2O2 Amino Acid Schiff Base and Its Coordination Compounds

“…As a consequence, they may interact with biomolecules, such as nucleic acids and proteins, within the interior of the microbe. They have been reported to bind to DNA nitrogen bases resulting in an alternation of the normal DNA transcription regulation thereby disrupting genome and cellular processes [27]. In most cases, the DNA-interaction with complexes depends on the structure and stability of the complexes as well as the nature of their ligands.…”

“…Currently there is a global shortage of efficient antimicrobials to successfully combat drug resistant pathogens. There is therefore a need for new or lead compounds as antibiotics [27]. Although, Schiff base of 1,4-benzenedicarboxaldehyde and some amino acids, including aminoethanoic acid and their coordination compounds have been synthesized and characterized [29].…”