Publications by authors named "Rodica Olar"

14 Publications

  • Page 1 of 1

New Cobalt (II) Complexes with Imidazole Derivatives: Antimicrobial Efficiency against Planktonic and Adherent Microbes and In Vitro Cytotoxicity Features.

Molecules 2020 Dec 24;26(1). Epub 2020 Dec 24.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Str., 050663 Bucharest, Romania.

Three novel Co(II) complexes of the type [Co(CHO)L] (where CHO is methacrylate anion; L = CHN (imidazole; HIm) (), CHN (2-methylimidazole; 2-MeIm) (), CHN (2-ethylimidazole; 2-EtIm) ()) have been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopic techniques, thermal analysis and single crystal X-ray diffraction. X-ray crystallography revealed for complexes () and () distorted trigonal bipyramid stereochemistry for Co(II), meanwhile for complex () evidenced that the unit cell comprises three molecular units with interesting structural features. In each unit, both stereochemistry adopted by metallic ion and coordination modes of carboxylate anions are different. The screening of antimicrobial activity revealed that planktonic cells were the most susceptible, with minimal inhibitory concentration (MIC) values of 7.8 μg/mL for complexes () and () and 15.6 μg/mL for complex (). Complexes () and () proved to be more active than complex () against the tested bacterial strains, both in planktonic and biofilm growth state, with MIC and minimal biofilm eradication concentration (MBEC) values ranging from 15.6 to 62.5 μg/mL, the best antibacterial effects being noticed against and . Remarkably, the MBEC values obtained for the four tested bacterial strains were either identical or even lower than the MIC ones. The cytotoxicity assay indicated that the tested complexes affected the cellular cycle of HeLa, HCT-8, and MG63 cells, probably by inhibiting the expression of vimentin and transient receptor potential canonical 1 (TRPC1). The obtained biological results recommend these complexes as potential candidates for the development of novel anti-biofilm agents.
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http://dx.doi.org/10.3390/molecules26010055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796409PMC
December 2020

Improvement in the Pharmacological Profile of Copper Biological Active Complexes by Their Incorporation into Organic or Inorganic Matrix.

Molecules 2020 Dec 10;25(24). Epub 2020 Dec 10.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Str., 050663 Bucharest, Romania.

Every year, more Cu(II) complexes are proven to be biologically active species, but very few are developed as drugs or entered in clinical trials. This is due to their poor water solubility and lipophilicity, low stability as well as in vivo inactivation. The possibility to improve their pharmacological and/or oral administration profile by incorporation into inorganic or organic matrix was studied. Most of them are either physically encapsulated or conjugated to the matrix via a moiety able to coordinate Cu(II). As a result, a large variety of species were developed as delivery carriers. The organic carriers include liposomes, synthetic or natural polymers or dendrimers, while the inorganic ones are based on carbon nanotubes, hydrotalcite and silica. Some hybrid organic-inorganic materials based on alginate-carbonate, gold-PEG and magnetic mesoporous silica-Schiff base were also developed for this purpose.
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http://dx.doi.org/10.3390/molecules25245830DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7763451PMC
December 2020

Rare-Earth Metal Complexes of the Antibacterial Drug Oxolinic Acid: Synthesis, Characterization, DNA/Protein Binding and Cytotoxicity Studies.

Molecules 2020 Nov 19;25(22). Epub 2020 Nov 19.

Department of General and Inorganic Chemistry, Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia St, 020956 Bucharest, Romania.

"Drug repositioning" is a current trend which proved useful in the search for new applications for existing, failed, no longer in use or abandoned drugs, particularly when addressing issues such as bacterial or cancer cells resistance to current therapeutic approaches. In this context, six new complexes of the first-generation quinolone oxolinic acid with rare-earth metal cations (Y, La, Sm, Eu, Gd, Tb) have been synthesized and characterized. The experimental data suggest that the quinolone acts as a bidentate ligand, binding to the metal ion via the keto and carboxylate oxygen atoms; these findings are supported by DFT (density functional theory) calculations for the Sm complex. The cytotoxic activity of the complexes, as well as the ligand, has been studied on MDA-MB 231 (human breast adenocarcinoma), LoVo (human colon adenocarcinoma) and HUVEC (normal human umbilical vein endothelial cells) cell lines. UV-Vis spectroscopy and competitive binding studies show that the complexes display binding affinities (K) towards double stranded DNA in the range of 9.33 × 10 - 10.72 × 10. Major and minor groove-binding most likely play a significant role in the interactions of the complexes with DNA. Moreover, the complexes bind human serum albumin more avidly than apo-transferrin.
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http://dx.doi.org/10.3390/molecules25225418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699381PMC
November 2020

Anti-biofilm FeO@C-[1,3,4]thiadiazolo[3,2-]pyrimidin-4-ium-2-thiolate Derivative Core-shell Nanocoatings.

Materials (Basel) 2020 Oct 17;13(20). Epub 2020 Oct 17.

Department of Microbiology, Faculty of Biology, University of Bucharest, 1-3 Aleea Portocalelor St., 60101 Bucharest, Romania.

The derivatives 5,7-dimethyl[1,3,4]thiadiazolo[3,2-]pyrimidin-4-ium-2-thiolate () and 7-methyl-5-phenyl[1,3,4]thiadiazolo[3,2-]pyrimidin-4-ium-2-thiolate () were fully characterized by single-crystal X-ray diffraction. Their supramolecular structure is built through both π-π stacking and C=S-π interactions for both compounds. The embedment of the tested compounds into FeO@C core-shell nanocoatings increased the protection degree against biofilms on the catheter surface, suggesting that these bioactive nanocoatings could be further developed as non-cytotoxic strategies for fighting biofilm-associated fungal infections.
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http://dx.doi.org/10.3390/ma13204640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7603173PMC
October 2020

Copper(II) Complexes with Mixed Heterocycle Ligands as Promising Antibacterial and Antitumor Species.

Molecules 2020 Aug 19;25(17). Epub 2020 Aug 19.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Str., 050663 Bucharest, Romania.

Complexes with mixed ligands [Cu(N-N)(pmtp)](ClO) (() N-N: 2,2'-bipyridine; () L: 1,10-phenanthroline and pmpt: 5-phenyl-7-methyl-1,2,4-triazolo[1,5-]pyrimidine) were synthesized and structurally and biologically characterized. Compound () crystallizes into space group and () in -1. Both complexes display an intermediate stereochemistry between the two five-coordinated ones. The biological tests indicated that the two compounds exhibited superoxide scavenging capacity, intercalative DNA properties, and metallonuclease activity. Tests on various cell systems indicated that the two complexes neither interfere with the proliferation of or BJ healthy skin cells, nor cause hemolysis in the active concentration range. Nevertheless, the compounds showed antibacterial potential, with complex () being significantly more active than complex () against all tested bacterial strains, both in planktonic and biofilm growth state. Both complexes exhibited a very good activity against B16 melanoma cells, with a higher specificity being displayed by compound (). Taken together, the results indicate that complexes () and () have specific biological relevance, with potential for the development of antitumor or antimicrobial drugs.
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http://dx.doi.org/10.3390/molecules25173777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7504215PMC
August 2020

X-ray Crystal Structure, Geometric Isomerism, and Antimicrobial Activity of New Copper(II) Carboxylate Complexes with Imidazole Derivatives.

Molecules 2018 Dec 9;23(12). Epub 2018 Dec 9.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90⁻92 Panduri Str., 050663 Bucharest, Romania.

Five new copper(II) acrylate complexes (acr is the acrylate anion: C₃H₃O₂) with imidazole derivatives (2-methylimidazole/2-MeIm, 5-methylimidazole/5-MeIm, 2-ethylimidazole/2-EtIm) of type: -[Cu(2-RIm)₂(acr)₂]·xH₂O ((): R = ⁻CH₃, x = 2; (): R = ⁻CH₂⁻CH₃, x = 0), -[Cu(2-RIm)₂(acr)₂] ((): R = ⁻CH₃; (): R = ⁻CH₂⁻CH₃) and -[Cu(5-RIm)₂(acr)₂] ((): R = ⁻CH₃) have been prepared and characterized by elemental analysis, Fourier Transform Infrared spectrometry (FTIR), Electron Paramagnetic Resonance (EPR), electronic reflectance spectroscopy, scanning electron microscopy, and mass spectrometry. The single crystal X-ray diffraction study of complexes () and () reveals that the copper(II) ion is located on an inversion center and show elongated octahedral geometry completed by two coplanar bidentate acrylates and two unidentate imidazole derivatives displayed in positions. For complex () the single crystal X-ray diffraction shows that the copper(II) ion is in a distorted octahedral environment which can be easily confused with a trigonal prism completed by two bidentate acrylates and two unidentate imidazole derivatives displayed in positions. These results indicate the fact that complexes () and () are the geometric isomers of the same compound bis(acrylate)-bis(2-ethylimidazole)-copper(II). Complexes () and (), as well as () and (), were produced simultaneously in the reaction of the corresponding copper(II) acrylate with imidazole derivatives in methanol solution. Furthermore, in order to be able to formulate potential applications of the obtained compounds, our next goal was to investigate the in vitro antimicrobial activity of the synthesized complexes against Gram-positive and Gram-negative bacteria, as well as fungal strains, of both clinical and ecological importance (biodeterioration of historical buildings). The isomers () and (), followed by () have shown the broadest range of antimicrobial activity. In case of () and () isomers, the trans isomer () was significantly more active than cis (), while the cis isomer () proved to be more active than trans (). Taken together, the biological evaluation results indicate that the trans () was the most active complex, demonstrating its potential for the development of novel antimicrobial agents, with potential applications in the biomedical and restoration of architectural monuments fields.
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http://dx.doi.org/10.3390/molecules23123253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6321156PMC
December 2018

Synthesis, Structural Characterization, Antimicrobial Activity, and In Vitro Biocompatibility of New Unsaturated Carboxylate Complexes with 2,2'-Bipyridine.

Molecules 2018 Jan 12;23(1). Epub 2018 Jan 12.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Str., 050663 Bucharest, Romania.

The synthesis, structural characterization, cytotoxicity, and antimicrobial properties of four new complexes formed by employing acrylate anion and 2,2'-bipyridine are reported herein. X-ray crystallography revealed the trinuclear nature of [Mn₃(2,2'-bipy)₂(C₃H₃O₂)₆] (), meanwhile complexes with general formula [M(2,2'-bipy)(C₃H₃O₂)₂(H₂O)]∙H₂O (() M: Ni, = 1, = 0; () M: Cu, = 1, = 0; () M: Zn, = 0, = 1; 2,2'-bipy: 2,2'-bipyridine; C₃H₃O₂: acrylate anion) were shown to be mononuclear. The lowest minimum inhibitory concentration (MIC) of 128 μg mL was recorded for all four tested complexes against , for complex () against , and for complex () against . Compounds () and () were also potent efflux pumps activity inhibitors (EPI), proving their potential for use in synergistic combinations with antibiotics. Complexes ()-() revealed that they were not cytotoxic to HCT-8 cells. They also proved to interfere with the cellular cycle of tumour HCT-8 cells by increasing the number of cells found in the S and G2/M phases. Taken together, these results demonstrate the potential of zinc and copper complexes for use in the development of novel antimicrobial and anti-proliferative agents.
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http://dx.doi.org/10.3390/molecules23010157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6017882PMC
January 2018

Synthesis, Physico-chemical Characterization, Crystal Structure and Influence on Microbial and Tumor Cells of Some Co(II) Complexes with 5,7-Dimethyl-1,2,4-triazolo[1,5-a]pyrimidine.

Molecules 2017 Jul 22;22(7). Epub 2017 Jul 22.

Department of Inorganic Chemistry, Faculty of Chemistry, University of Bucharest, 90-92 Panduri Str., 050663 Bucharest, Romania.

Three complexes, namely [Co(dmtp)₂(OH₂)₄][CoCl₄] (), [Co(dmtp)₂Cl₂] () and [Co(dmtp)₂(OH₂)₄]Cl₂∙2H₂O () (dmtp: 5,7-dimethyl-1,2,4-triazolo[1,5-]pyrimidine), were synthesized and characterized by spectral (IR, UV-Vis-NIR), and magnetic measurements at room temperature, as well as single crystal X-ray diffraction. Complex () crystallizes in monoclinic system (space group 2/c), complex () adopts an orthorhombic system (space group bca), and complex () crystallizes in triclinic system (space group P1). Various types of extended hydrogen bonds and π-π interactions provide a supramolecular architecture for all complexes. All species were evaluated for antimicrobial activity towards planktonic and biofilm-embedded microbial cells and influence on HEp-2 cell viability, cellular cycle and gene expression.
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http://dx.doi.org/10.3390/molecules22071233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6152184PMC
July 2017

Synthesis and Structural Investigation of New Bio-Relevant Complexes of Lanthanides with 5-Hydroxyflavone: DNA Binding and Protein Interaction Studies.

Molecules 2016 Dec 16;21(12). Epub 2016 Dec 16.

Department of General and Inorganic Chemistry, Faculty of Pharmacy, "Carol Davila" University of Medicine and Pharmacy, 6 Traian Vuia Str., 020956 Bucharest, Romania.

In the present work, we attempted to develop new metal coordination complexes of the natural flavonoid 5-hydroxyflavone with Sm(III), Eu(III), Gd(III), Tb(III). The resultant hydroxo complexes have been characterized by a variety of spectroscopic techniques, including fluorescence, FT-IR, UV-Vis, EPR and mass spectral studies. The general chemical formula of the complexes is [Ln(CH₉O₃)₃(OH)₂(H₂O)]·H₂O, where Ln is the lanthanide cation and x = 0 for Sm(III), x = 1 for Eu(III), Gd(III), Tb(III) and = 0 for Sm(III), Gd(III), Tb(III), = 1 for Eu(III), respectively. The proposed structures of the complexes were optimized by DFT calculations. Theoretical calculations and experimental determinations sustain the proposed structures of the hydroxo complexes, with two molecules of 5-hydroxyflavone acting as monoanionic bidentate chelate ligands. The interaction of the complexes with calf thymus DNA has been explored by fluorescence titration and UV-Vis absorption binding studies, and revealed that the synthesized complexes interact with DNA with binding constants (K) ~ 10⁴. Human serum albumin (HSA) and transferrin (Tf) binding studies have also been performed by fluorescence titration techniques (fluorescence quenching studies, synchronous fluorescence spectra). The apparent association constants (K) and thermodynamic parameters have been calculated from the fluorescence quenching experiment at 299 K, 308 K, and 318 K. The quenching curves indicate that the complexes bind to HSA with smaller affinity than the ligand, but to Tf with higher binding affinities than the ligand.
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http://dx.doi.org/10.3390/molecules21121737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6273368PMC
December 2016

Synthesis and characterization of some new complexes of magnesium (II) and zinc (II) with the natural flavonoid primuletin.

Molecules 2013 Jul 1;18(7):7631-45. Epub 2013 Jul 1.

Department of General and Inorganic Chemistry, Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia St, Bucharest 020956, Romania.

Two new metal complexes formulated as [Mg(L)2(H2O)2]·H2O (1) and [Zn(L)2(H2O)2]·0.5H2O (2), where HL = 5-hydroxyflavone (primuletin), have been synthesized and characterized by elemental and thermal analyses, molar conductance, IR, UV-Vis, 1H- and 13C-NMR, fluorescence and mass spectra. In solid state, complexes had shown higher fluorescence intensities comparing to the free ligand, and this behavior is appreciated as a consequence of the coordination process.
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http://dx.doi.org/10.3390/molecules18077631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6270113PMC
July 2013

N,N-dimethylbiguanide complexes displaying low cytotoxicity as potential large spectrum antimicrobial agents.

Eur J Med Chem 2010 Jul 27;45(7):3027-34. Epub 2010 Mar 27.

Department of Inorganic Chemistry, University of Bucharest, 90-92 Panduri Street, Bucharest, Romania.

The new complexes M(DMBG)(2)(ClO(4))(2) (M:Mn, Ni, Cu and Zn; DMBG: N,N-dimethylbiguanide) have been synthesized and characterized by IR, EPR, (1)H NMR, (13)C NMR as well as electronic spectroscopy data. Complex [Ni(DMBG)(2)](ClO(4))(2).2DMF (DMF: N,N-dimethylformamide) crystallizes in the monoclinic P2(1)/c space group while [Cu(DMBG)(2)](ClO(4))(2) adopt monoclinic P21/c space group as X-ray single crystal data indicate. The redox behavior of complexes was investigated by cyclic voltammetry. The metal-free N,N-dimethylbiguanide and complexes exhibit specific anti-infective properties as demonstrated the low MIC values, a large antimicrobial spectrum and also inhibit the ability of Pseudomonas aeruginosa and Staphylococcus aureus strains to colonize the inert surfaces. The complexes exhibit also a low cytotoxicity levels on HeLa cells.
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http://dx.doi.org/10.1016/j.ejmech.2010.03.033DOI Listing
July 2010

Prospects for new antimicrobials based on N,N-dimethylbiguanide complexes as effective agents on both planktonic and adhered microbial strains.

Eur J Med Chem 2010 Jul 17;45(7):2868-75. Epub 2010 Mar 17.

Department of Inorganic Chemistry, University of Bucharest, 90-92 Panduri St., 050663 Bucharest, Romania.

Metal-free N,N-dimethylbiguanidium acetate and novel complexes M(DMBG)(2)(CH(3)COO)(2).nH(2)O (M: Mn(II), Ni(II), Cu(II) and Zn(II)) were screened for their antimicrobial properties against Gram-positive (Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus), Gram-negative (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa) bacteria and fungal (Candida albicans) strains. The ability of compounds to inhibit the microbial adherence ability to the inert substratum as well as their cytotoxicity was also assessed. Our results are demonstrating that some of the tested compounds are exhibiting potent antimicrobial activity accompanied by low cytotoxicity on HeLa cells. The complexes were characterized using microanalytical, IR, EPR, (1)H NMR as well as UV-vis methods. The redox behaviour of complexes was investigated by cyclic voltammetry. The new derivative (HDMBG)(CH(3)COO) crystallizes in the monoclinic P2(1)/n space group as X-ray single-crystal data indicate.
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http://dx.doi.org/10.1016/j.ejmech.2010.03.009DOI Listing
July 2010

Synthesis, spectral and thermal studies of new rutin vanadyl complexes.

Molecules 2010 Mar 10;15(3):1578-89. Epub 2010 Mar 10.

Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia St, 020956 Bucharest, Romania.

Complexes between oxovanadium (IV) cation and flavonoid derivatives were developed recently in order to increase the intestinal absorption and to reduce the toxicity of vanadium compounds. For these reasons, is interesting to investigate the complexation process between flavonoid rutin (Rut) and vanadyl cation in order to isolate new complexes. Two new complexes [VO(Rut)(H2O)2](SO4)0.5 x 2 H2O and [VO(Rut)2] x 4 H2O have been obtained and characterized by elemental and thermal analyses and several spectroscopic techniques (ESI-MS, IR, UV-Vis, fluorescence). The studies concerning complex formation between vanadyl and rutin (Rut) performed in different solutions show the formation of mononuclear complexes with 1:1 and 1:2 metal to ligand stoichiometry.
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http://dx.doi.org/10.3390/molecules15031578DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6257295PMC
March 2010

Novel antipathogenic strategies against adherent enterobacterial strains isolated from the hospital environment.

Roum Arch Microbiol Immunol 2008 Jan-Jun;67(1-2):43-8

University of Bucharest, Faculty of Biology, Microbiology Immunology Department, Bucharest, Romania.

The emergence of the bacterial antibiotic multi-resistance made more and more stringent the developing of new anti-microbial strategies. The purpose of the present study was to investigate the antimicrobial potential of six (6) newly synthesized chemical compounds (derivating from phenantroline and dimethylguanin-copper complex combinations) versus 97 enterobacterial strains isolated from the hospital environment. The qualitative screening of the antimicrobial activity of the chemical compounds was performed by an adapted diffusion method. The minimal inhibitory concentrations (MIC) of the active chemical compounds were established by Mueller Hinton broth microdillution method. The tested chemical compounds were also tested for their ability to inhibit microbial adherence and biofilm development on inert substrata by a simple microtiter method. All six chemical compounds proved to have antimicrobial activity versus the most of the tested strains, the phenantroline derivatives exhibiting higher antimicrobial activity than the dimethylguanidine-copper complex combinations. The subinhibitory concentrations of the tested chemical products slightly inhibited the adherence ability of the bacterial strains to the inert substratum. Our results demonstrated that phenantroline derivatives may represent a new strategy of antimicrobial treatment, simultaneously with the bactericidal effect, the subinhibitory concentrations of these newly synthesized chemical compounds decreasing the adherence ability of bacteria to the inert substratum.
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March 2009