scholarly journals Synthesis, Structure, and Biological Assays of Novel Trifluoromethyldiazepine–Metal Complexes

2020 ◽  
Vol 73 (1) ◽  
pp. 49
Author(s):  
Mariana Rocha ◽  
Gustavo A. Echeverría ◽  
Oscar E. Piro ◽  
Jorge J. Jios ◽  
Rocío D. I. Molina ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Biofilm Formation ◽  
Crystal Packing ◽  
Free Ligand ◽  
Antibacterial Properties ◽  
Bactericidal Effect ◽  
Biological Assays ◽  
Additional Information ◽  
Gram Positive Bacteria ◽  
Mechanism Of Inhibition

A new series of CuII, NiII, CoII, and MnIII complexes have been synthesised from the (6Z)-6-(7-trifluoromethyl-1,2,3,4-tetrahydro-5H-1,4-diazepin-5-ylidene)cyclohexa-2,4-dien-1-one (HDZP) ligand. These complexes were characterised by elemental, spectroscopic (IR and UV-vis), and thermal analysis. The crystal structure of Cu-DZP was solved by X-ray diffraction methods. The complex crystallises in the monoclinic P21/c space group, with two molecules per unit cell. The crystal lattice is stabilised by different intra and intermolecular interactions. Hirshfeld surface analysis was employed to obtain additional information about interactions that are responsible for the crystal packing. Quantitative examination of the fingerprint plots indicated the dominant contribution of H⋯H and H⋯X (X=O, F) interactions in the crystal packing. In addition, C–H⋯chelate ring (CR) and C–H⋯π interactions are described in detail and evaluated using DFT calculations. The antibacterial properties and the mechanism of inhibition of the main bacterial resistant mechanism, the biofilm, of the metal complexes and free ligand were investigated. [Mn(DZP)3]·2H2O was the most active complex against the Pseudomonas aeruginosa biofilm formation with an inhibition of 40%. However, none of the complexes inhibit more than 25% of the Gram negative bacteria microbial development. The most meaningful result was the bactericidal effect of [Co(DZP)2(H2O)2]·2H2O against the Gram positive bacteria, Staphylococcus aureus, which inhibits the bacterial development and significantly reduces the biofilm formation at low concentration.

scholarly journals Synthesis and Antibacterial Studies of Novel Phosphorus Ligand 5-(2-diphenylphosphino) phenyl-1,2-dihydro-1,2,4-triazole-3-thione and its Metal Complexes with some Transition Metals

2010 ◽  
Vol 4 (2) ◽  
pp. 37-45
Author(s):  
Matheel D. Al-Sabti ◽  
Ahmed A. H. Al-Amiery ◽  
Thorria R. Marzoog ◽  
Yasmien K. Al-Majedy
Keyword(s):  
Metal Complexes ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Cadmium Complex ◽  
Gram Positive Bacteria ◽  
Visible Spectra ◽  
Number Of Microorganisms ◽  
Ft Ir ◽  
The Stability

This study involves the chemical synthesis of the novel ligand 5-(2-diphenylphosphino) phenyl-1,2-dihydro-1,2,4-triazole-3-thione (DPDTT) by the reaction of 2-diphenylphosphino benzoic acid with absolute ethanol that yield ethyl 2-diphenylphosphino benzoate and by cyclization of this compound with thiosemicarbazide, DPDTT will be produced. The chelating complexes of this ligand with Cr(III), Co(II), Ni(II), Cu(II) and Cd(II) were also prepared and studied. The new complexes were characterized by FT-IR, UV/visible spectra, and room temperature magnetic susceptibility. The stability for the prepared complexes was also measured using the density function theory and it was found that the cadmium complex is the most stable and the chromium complex is the least stable. Free ligand and its metal complexes have been tested in vitro against a number of microorganisms, like gram positive bacteria Staphylococcus aureus and gram negative bacteria E. coli, Proteus vulgaris, Pseudomonas and Klebsiella in order to assess their antimicrobial properties. All complexes showed considerable activity against all the studied bacteria.

scholarly journals Chemical Composition, and Evaluation of Antibacterial，Antibiofilm and Synergistic Effects with Conventional Antibiotics of Essential Oil from Mallotus repandus

2021 ◽  
Vol 15 (4) ◽  
pp. 324-329
Author(s):  
Pengxiang Lai ◽  
Xin-Chen Zhang ◽  
Lin Zhu ◽  
Xin-Yu Li ◽  
Li-Chuan Liu
Keyword(s):  
Essential Oil ◽  
Biofilm Formation ◽  
Synergistic Effects ◽  
Antibacterial Properties ◽  
Good Alternative ◽  
Bactericidal Effect ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Mallotus Repandus

The essential oil (EO) of aerial parts of Mallotus repandus (Willd.) Muell. Arg. was extracted by hydrodistillation and characterized by GC/FID and GC/MS. Fifty-one compounds comprising 97.1% of the EO were identified, of which α-humulene (18.7%), β-selinene (12.8%), aciphyllene (10.7%), (E)-caryophyllene (8.4%), α-copaene (5.5%), humulene epoxide II (4.9%) and caryophyllene oxide (4.3%) were the major compounds. The EO was evaluated for antibacterial properties using broth microdilution method and crystal-violet static biofilm formation assay. The M. repandus EO possessed a bactericidal effect against tested gram-positive bacteria strains (MIC = MBC: 0.05-0.10 mg/mL). Further, the EO showed the ability to inhibit the biofilm formation of Staphylococcus aureus. In addition, the potential synergistic effect was assessed by checkerboard method. Combination of the M. repandus EO with Streptomycin showed synergistic effects against the tested bacterial strains. This study demonstrates that M. repandus EO could be further explored as good alternative for potential pharmaceuticals.

scholarly journals Antibacterial properties of silver nanoparticles and their membranotrophic action

2021 ◽  
pp. 64-71
Author(s):  
Lilit S. Gabrielyan ◽  
Armen A. Trchounian
Keyword(s):  
Antibacterial Properties ◽  
Bactericidal Effect ◽  
H2 Production ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Silver Nps ◽  
H2 Yield ◽  
K 12 ◽  
Energy Dependent

Nowadays, metal nanoparticles (NPs) can be considered as alternative agents for overcoming antibiotic resistance. The effect of silver NPs on gram-positive (Enterococcus hirae ATCC9790, Staphylococcus aureus MDC5233) and gram-negative (Escherichia coli K-12, Salmonella typhimurium MDC1759) bacteria have been investigated in this work. Silver NPs demonstrated antibacterial activity against the bacteria used, expressed in the decrease of the specific growth rate and the number of colony forming units. Moreover, the bactericidal effect of silver NPs on gram-positive bacteria was more pronounced than on gram-negative bacteria. In order to find out the mechanisms of NPs’ effects, the change of the redox potential, the hydrogen (H2) production ability, and the protons flux across the bacterial membrane have been also studied. The addition of NPs led to inhibition of H2 yield and to change of the energy-dependent proton flux through Fo F1-ATPase, indicating the silver NPs effect on the activity of membrane-bound enzymes. The data obtained point out that silver NPs show a pronounced antibacterial effect against the studied bacteria and can be used in biomedicine.

scholarly journals Spectroscopic, thermal and antibacterial studies on Mn(II) and Co(II) complexes derived from thiosemicarbazone

2009 ◽  
Vol 74 (8-9) ◽  
pp. 907-915 ◽  
Author(s):  
Sulekh Chandra ◽  
Monika Tyagi ◽  
Moamen Refat
Keyword(s):  
Magnetic Susceptibility ◽  
Thermogravimetric Analysis ◽  
Metal Complexes ◽  
Thermal Studies ◽  
Free Ligand ◽  
Antibacterial Properties ◽  
Molar Conductance ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Antibacterial Studies

Mn(II) and Co(II) complexes having the general composition [M(L)2X2] (where L = 2-pyridinecarboxaldehyde thiosemicarbazone, M = Mn(II) and Co(II), X = Cl- and - NO3 ) were synthesized. All the metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, EPR, electronic spectral studies and thermogravimetric analysis (TG). Based on the spectral studies, an octahedral geometry was assigned for all the complexes. Thermal studies of the compounds suggest that the complexes are more stable than the free ligand. This fact was supported by the kinetic parameters calculated using the Horowitz-Metzger (H-M) and Coats-Redfern (C-R) equations. The antibacterial properties of the ligand and its metal complexes were also examined and it was observed that the complexes are more potent bactericides than the free ligand.

scholarly journals Synthesis, Characterization, Thermal Analysis and Structural Studies of New Complexes with Tetradentate Ligand

2015 ◽  
Vol 12 (2) ◽  
pp. 379-393 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Metal Complexes ◽  
Bacterial Species ◽  
Free Ligand ◽  
Activation Parameters ◽  
Heat Of Formation ◽  
Spectroscopic Techniques ◽  
Tetradentate Ligand ◽  
Gram Positive Bacteria ◽  
Square Planar ◽  
And Staphylococcus Aureus

Some new complexes of 4-(5-(1,5-dimethyl-3-oxo-2-phenyl pyrazolidin-4- ylimino)-3,3-dimethyl cyclohexylideneamino) -1,5- dimethyl-2- phenyl -1H- pyrazol -3(2H) –one (L) with Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Pd(II), Re(V) and Pt(IV) were prepared. The ligand and its metal complexes were characterized by phisco- chemical spectroscopic techniques. The spectral data were suggested that the (L) as a neutral tetradentate ligand is coordinated with the metal ions through two nitrogen and two oxygen atoms. These studies revealed Octahedral geometries for all metal complexes, except square planar for Pd(II) complex. Moreover, the thermodynamic activation parameters, such as ?E*, ?H, ?S, ?G and K are calculated from the TGA curves using Coats –Redfern method. Hyper Chem -8 program has been used to predict structural geometries for compounds in gas phase. The heat of formation (?Hf) and bin ding energy (?Eb) at 298 °K for the free ligand and its metal complexes were calculated by PM3 method. The synthesized ligands and their metal complexes were screened for their biological activity against bacterial species, two Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa).

scholarly journals Synthesis, Characterization and Antimicrobial Activity of Transition Metal Complexes of Schiff Base Ligand Derived from 3-Ethoxy Salicylaldehyde and 2-(2-Aminophenyl) 1-H-benzimidazole

2012 ◽  
Vol 9 (4) ◽  
pp. 2516-2523 ◽  
Author(s):  
Matangi Sunitha ◽  
Pragathi Jogi ◽  
Bathini Ushaiah ◽  
C. Gyana Kumari
Keyword(s):  
Antimicrobial Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Mass Spectra ◽  
Free Ligand ◽  
Spectral Studies ◽  
Gram Negative Bacteria ◽  
Activity Data ◽  
E Coli ◽  
Gram Positive Bacteria

Metal complexes of Ni(II), Co(II), Cu(II), Mn(II) and Zn(II) VO(IV) with a Schiff base derived from 3-Ethoxy Salicylaldehyde and 2-(2-amino-phenyl)1-H-Benzimidazol(2-[(Z)-{(2-(1H-benzimidazole-2yl)phenyl] imino} methyl]-6-ethoxy phenol-BMEP) were synthesized successfully. The resulting complexes were characterized by elemental analysis, magnetic moment measurements, conductivity measurements, IR, UV-VIS, 1H NMR, mass spectra and ESR spectral studies. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the ligand and its metal complexes were studied against two gram negative bacteria:E. coli, Pseudomonas flourescenceand two gram positive bacteria:Bacillus subitilis, Staphylococcus aureus. The activity data show that the metal complexes are more potent than the free ligand.

Synthesis, Characterization and in vitro Biological Evaluation of a New Schiff Base Derived from Drug and its Complexes with Transition Metal Ions

2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Transition Metal Ions ◽  
Biological Evaluation ◽  
Pyridoxal Hydrochloride

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.

Induction of Apoptosis by Nano‐Synthesized Complexes of H2L and its Cu(II) Complex in Human Hepatocellular Carcinoma Cells

2020 ◽  
Vol 20 ◽  
Author(s):  
Thoria Diab ◽  
Tarek M. Mohamed ◽  
Alaa Hamed ◽  
Mohamed Gaber
Keyword(s):  
Cell Cycle ◽  
Metal Complexes ◽  
Hepg2 Cells ◽  
Therapeutic Potential ◽  
Free Ligand ◽  
Organometallic Complexes ◽  
Phase Cell ◽  
Sod Activity ◽  
Induced Apoptosis

Background: Chemotherapy is currently the most utilized treatment for cancer. Therapeutic potential of metal complexes in cancer therapy has attracted a lot of interest. The mechanisms of action of most organometallic complexes are poorly understood. Objective: This study was designed to explore the mechanisms governing the anti-proliferative effect of the free ligand N1,N6‐bis((2‐hydroxynaphthalin‐1‐yl)methinyl)) adipohydrazone (H2L) and its complexes of Mn(II), Co(II), Ni(II) and Cu(II). Methods: Cells were exposed to H2L or its metal complexes where cell viability determined by MTT assay. Cell cycle was analysed by flow cytometry. In addition, qRT-PCR was used to monitor the expression of Bax and Bcl-2. Moreover, molecular docking was carried out to find the potentiality of Cu(II) complex as an inhibitor of Adenosine Deaminase (ADA). ADA, Superoxide Dismutase (SOD) and reduced Glutathione (GSH) levels were measured in the most affected cancer cell line. Results: The obtained results demonstrated that H2L and its Cu(II) complex exhibited a strong cytotoxic activity compared to other complexes against HepG2 cells (IC50 = 4.14±0.036μM/ml and 3.2±0.02μM/ml), respectively. Both H2L and its Cu(II) complex induced G2/M phase cell cycle arrest in HepG2 cells. Additionally, they induced apoptosis in HepG2 cells via upregulation of Bax and downregulation of Bcl-2. Interestingly, the activity of ADA was decreased by 2.8 fold in HepG2 cells treated with Cu(II) complex compared to untreated cells. An increase of SOD activity and GSH level in HepG2 cells compared to control was observed. Conclusion: The results concluded that Cu(II) complex of H2L induced apoptosis in HepG2 cells. Further studies are needed to confirm its anti-cancer effect in vivo.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

scholarly journals Antimicrobial Activity and Mode of Action of Celastrol, a Nortriterpen Quinone Isolated from Natural Sources

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 591
Author(s):  
Nayely Padilla-Montaño ◽  
Leandro de León Guerra ◽  
Laila Moujir
Keyword(s):  
Antimicrobial Activity ◽  
Cytoplasmic Membrane ◽  
Bactericidal Effect ◽  
Inoculum Size ◽  
Bacterial Populations ◽  
Gram Positive Bacteria ◽  
Dna And Rna ◽  
Dna And Rna Synthesis ◽  
Natural Derivative ◽  
Interesting Alternative

Species of the Celastraceae family are traditionally consumed in different world regions for their stimulating properties. Celastrol, a triterpene methylene quinone isolated from plants of celastraceas, specifically activates satiety centers in the brain that play an important role in controlling body weight. In this work, the antimicrobial activity and mechanism of action of celastrol and a natural derivative, pristimerin, were investigated in Bacillus subtilis. Celastrol showed a higher antimicrobial activity compared with pristimerin, being active against Gram-positive bacteria with minimum inhibitory concentrations (MICs) that ranged between 0.16 and 2.5 µg/mL. Killing curves displayed a bactericidal effect that was dependent on the inoculum size. Monitoring of macromolecular synthesis in bacterial populations treated with these compounds revealed inhibition in the incorporation of all radiolabeled precursors, but not simultaneously. Celastrol at 3 µg/mL and pristimerin at 10 µg/mL affected DNA and RNA synthesis first, followed by protein synthesis, although the inhibitory action on the uptake of radiolabeled precursors was more dramatic with celastrol. This compound also caused cytoplasmic membrane disruption observed by potassium leakage and formation of mesosome-like structures. The inhibition of oxygen consumption of whole and disrupted cells after treatments with both quinones indicates damage in the cellular structure, suggesting the cytoplasmic membrane as a potential target. These findings indicate that celastrol could be considered as an interesting alternative to control outbreaks caused by spore-forming bacteria.

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