ABSTRACT
One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel iron(III) complexes with the non-steroidal anti-inflammatory drugs diflunisal and diclofenac in the presence or absence of the nitrogen donors 1,10-phenanthroline or pyridine were isolated and characterized by diverse techniques. The complexes were evaluated for their ability to scavenge in vitro free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, revealing their selective potency towards hydroxyl radicals. The in vitro inhibitory activity of the complexes towards the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated, and their potential to achieve neuroprotection appeared promising. The interaction of the complexes with calf-thymus DNA was examined in vitro, revealing their ability to intercalate in-between DNA nucleobases. The affinity of the complexes for serum albumins was evaluated in vitro and revealed their tight and reversible binding.
Subject(s)
Antioxidants , Coordination Complexes , Antioxidants/pharmacology , Antioxidants/chemistry , Ferric Compounds , Cholinergic Antagonists , Butyrylcholinesterase , Acetylcholinesterase , Coordination Complexes/chemistry , Anti-Inflammatory Agents, Non-Steroidal/chemistry , DNA/chemistryABSTRACT
Five novel nickel(II) complexes with the non-steroidal anti-inflammatory drug sodium meclofenamate (Na-mclf) have been synthesized and characterized in the absence or co-existence of the nitrogen-donors imidazole (Himi), 2,2'-bipyridylamine (bipyam), 2,2'-bipyridylketoxime (Hpko) and 2,9-dimethyl-1,10-phenanthroline (neoc); namely [Ni(mclf-O)2(Himi)2(MeOH)2], [Ni(mclf-O)2(MeOH)4], [Ni(mclf-O)(mclf-O,O')(bipyam)(MeOH)]·0.25MeOH, [Ni(mclf-O,O')2(neoc)] and [Ni(mclf-O)2(Hpko-N,N')2]·MeOH·0.5H2O. The affinity of the complexes for calf-thymus (CT) DNA was investigated by various techniques and intercalation is suggested as the most possible interaction mode. The interaction of the complexes for bovine and human serum albumins was also investigated in order to determine the binding constants, concluding that the complexes bind reversibly to albumins for the transportation towards their target cells or tissues and their release upon arrival at biotargets. The antioxidant activity of the compounds was evaluated via their ability to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and to reduce H2O2. For the determination of the anticholinergic ability of the complexes the in vitro inhibitory activity against the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated and presented promising results. The in silico molecular modeling calculations employed provide useful insights for the understanding of the mechanism of action of the studied complexes at a molecular level. This applies on both the impairment of DNA by its binding with the studied complexes and transportation through serum albumins, as well as the ability of these compounds to act as anticholinergic agents.
Subject(s)
Coordination Complexes/chemistry , DNA/metabolism , Meclofenamic Acid/analogs & derivatives , Serum Albumin, Bovine/metabolism , Serum Albumin, Human/metabolism , Acetylcholinesterase/chemistry , Animals , Butyrylcholinesterase/chemistry , Cattle , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/metabolism , Coordination Complexes/chemical synthesis , Coordination Complexes/metabolism , Free Radical Scavengers/chemical synthesis , Free Radical Scavengers/chemistry , Free Radical Scavengers/metabolism , Humans , Meclofenamic Acid/chemical synthesis , Meclofenamic Acid/metabolism , Molecular Docking Simulation , Molecular Structure , Nickel/chemistryABSTRACT
The interaction of copper(II) with the non-steroidal anti-inflammatory drug sodium meclofenamate (Na-mclf) in the presence or absence of the nitrogen-donor co-ligands pyridine (py) or 2,2'-bipyridylamine (bipyam), yielded the novel Cu(II) complexes [Cu2(mclf-O,O')4(MeOH)2]·2MeOH (1·2MeOH), [Cu(mclf-O)2(py)3]·H2O·0.5MeOH (2·H2O·0.5MeOH) and [Cu(mclf-O,O')2(bipyam)] (3). The characterization of the complexes was achieved by various techniques, including single-crystal X-ray crystallography. In order to study the binding mode and strength of the complexes to calf-thymus (CT) DNA, various techniques were employed which suggested intercalation between the DNA-bases as the most possible interaction mode. Competitive studies with ethidium bromide (EB) revealed the ability of the complexes to displace the EB from the EB-DNA adduct, verifying the intercalative binding mode. The affinity of the complexes to bovine and human serum albumin proteins (SAs) was investigated by fluorescence emission spectroscopy and the corresponding binding constants bear relatively high values, showing that the complexes bind tightly and possibly reversibly to SAs. The antioxidant activity of the complexes against 1,1-diphenyl-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and the ability to reduce H2O2 proved to be of significant magnitude. The in vitro inhibitory activity against the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was evaluated, in order to assess the anticholinergic ability of the complexes, which appeared promising.
