Synthesis and Characterization of Tetrahydropyran-Based Bacterial Topoisomerase Inhibitors with Antibacterial Activity against Gram-Negative Bacteria

Curcumin, a diarylheptanoids compound which isolated primary from Curcuma longa, exhibits a variety of exciting biological activities, including as an antibacterial agent. In the present study, a sulfanilamide-contained curcumin compound was synthesized and characterized to investigate the antibacterial activity against gram-positive bacteria S. aureus, B. subtilis and gram-negative bacteria E. coli. The characterization of the synthesized compound was determined by analysing peak absorbance, functional group, and molecular weight using mass spectroscopy, UV/Vis and FTIR spectrophotometry. Curcumin-sulfanilamide compound exhibited the best antibacterial activity against gram-negative bacteria compared to curcumin and the curcumin-derived compound containing isoxazole with inhibitory zone of 11 mm.

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Al2O3 Nanopowders, a Suitable Compound for Active Control of Biofouling

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.32.71 ◽

2015 ◽

Vol 32 ◽

pp. 71-80

Author(s):

Mohsen Mehregan ◽

Hossein Soltaninejad ◽

Behnaz Toluei Nia ◽

Hadi Zare-Zardini ◽

Masoud Zare-Shehneh ◽

...

Keyword(s):

Electron Microscopy ◽

Antibacterial Activity ◽

Blood Cells ◽

Gram Negative Bacteria ◽

Bacterial Strains ◽

X Ray Diffraction ◽

Gram Positive ◽

Gram Negative ◽

X Ray

The formation of biofilm (Biofouling) in different surface is the great concern in types of fields, especially in medical and health system as well as in membrane technology. The present study deals with the synthesis and characterization of Al2O3 nanopowders with antibacterial activity which can be a potentially utilized material for biocompatible implants. Nanostructure was synthesized based on sol-gel method and then, crystallite size, and microstructural and morphological characterization of nanostructure were determined by X-ray diffraction, electron-microscopic techniques - scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to X-ray diffraction, the value of particle size for Al2O3 nanopowders is 20.85 nm. In the following, the antibacterial activity of Al2O3 nanoparticles was assessed on three gram positive and three gram negative bacteria by radial diffusion assay and measurement of minimum inhibitory concentration (MIC). The toxicity of Al2O3 nanopowders on blood cells was also assessed. The results showed that this nanostructure has potent antibacterial activity against gram positive and gram negative bacteria. The synthesized Al2O3 nanopowders showed the antimicrobial activity against antibiotic resistant bacterium, Staphylococcus aureus. Significant antibacterial activity of this nanostructure was seen to have a greatest effect on Bacillus cereus with the MIC value of 9.2 μg/ml; while, among bacterial strains, Salmonellatyphimurium was investigated to be the most resistant one with the MIC of 35.6 μg/ml. Al2O3 nanopowders showed no toxicity on blood cells. according to acquired data in this study, Al2O3 nanopowders may be a good material for inhibition of biofilm formation.

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Synthesis and characterization of new copper(II) complex compounds with chlorhexidine. Part I

Open Chemistry ◽

10.2478/s11532-010-0028-9 ◽

2010 ◽

Vol 8 (3) ◽

pp. 543-549 ◽

Cited By ~ 5

Author(s):

Mirela Călinescu ◽

Ticuţa Negreanu-Pîrjol ◽

Rodica Georgescu ◽

Octavian Călinescu

Keyword(s):

Antimicrobial Activity ◽

Metal Salt ◽

Complex Compounds ◽

Synthesis And Characterization ◽

Gram Negative Bacteria ◽

Reaction Conditions ◽

Gram Negative ◽

Imine Nitrogen

AbstractThree new copper(II) complex compounds with chlorhexidine diacetate as a ligand have been prepared and characterized by elemental and thermogravimetrical analyses, molar conductances, magnetic susceptibility measurements, infrared, electronic and EPR spectra. The complexes correspond to the formulas: [Cu2(CHX)Cl4]·2C2H5OH, [Cu2(CHX)Br4]·2C2H5OH and [Cu2(CHX)(CH3COO)2] (CH3COO)2·2C2H5OH, where CHX = chlorhexidine, their composition and stereochemistry depending on the reaction conditions and the metal salt used. Chlorhexidine acts as neutral tetradentate NNNN donor, coordinating through the four imine nitrogen atoms. Investigations on antimicrobial activity in vitro show that all the complexes are active against the tested microorganisms, the complex with chloride being more active against Gram negative bacteria than chlorhexidine diacetate..

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In-vitro Antioxidant and Antibacterial Activity of Methanolic Extract of Shorea robusta Gaertn. F. Resin

International Journal of Pharmaceutical and Phytopharmacological Research ◽

10.24896/eijppr.2016641 ◽

2016 ◽

Vol 6 (4) ◽

pp. 68

Author(s):

Sushma Vashisht ◽

Manish Pal Singh ◽

Viney Chawla

Keyword(s):

Antibacterial Activity ◽

Methanolic Extract ◽

Diffusion Method ◽

Gram Negative Bacteria ◽

Disc Diffusion ◽

Gram Positive ◽

Gram Negative ◽

Shorea Robusta ◽

Dose Dependent ◽

Resin Extract

The methanolic extract of the resin of Shorea robusta was subjected to investigate its antioxidant and antibacterial properties its utility in free radical mediated diseases including diabetic, cardiovascular, cancer etc. The methanol extract of the resin was tested for antioxidant activity using scavenging activity of DPPH (1,1-diphenyl-2-picrylhydrazil) radical method, reducing power by FeCl3 and antibacterial activity against gram positive and gram negative bacteria using disc diffusion method. The phytochemical screening considered the presence of triterpenoids, tannins and flavoniods. Overall, the plant extract is a source of natural antioxidants which might be helpful in preventing the progress of various oxidative stress mediated diseases including aging. The half inhibition concentration (IC50) of resin extract of Shorea robusta and ascorbic acid were 35.60 µg/ml and 31.91 µg/ml respectively. The resin extract exhibit a significant dose dependent inhibition of DPPH activity. Antibacterial activity was observed against gram positive and gram negative bacteria in dose dependent manner.Key Words: Shorea robusta, antioxidant, antibacterial, Disc-diffusion, DPPH.

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Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

International Journal of Pharmaceutical Quality Assurance ◽

10.25258/ijpqa.10.3.25 ◽

2019 ◽

Vol 10 (03) ◽

Author(s):

Elaf Ayad Kadhem ◽

Miaad Hamzah Zghair ◽

Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽

Hussam H. Tizkam ◽

Shoeb Alahmad

Keyword(s):

Antibacterial Activity ◽

Magnesium Oxide ◽

Diffusion Method ◽

Oxide Nanoparticles ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Magnesium Oxide Nanoparticles ◽

Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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Electrophysiological Characterization of Transport Across Outer Membrane Channels from Gram-Negative Bacteria in Their Native Environment

10.26434/chemrxiv.8282204.v1 ◽

2019 ◽

Author(s):

Jiajun Wang ◽

Rémi Terrasse ◽

Jayesh Arun Bafna ◽

Lorraine Benier ◽

Mathias Winterhalter

Keyword(s):

Outer Membrane ◽

Lipid Membrane ◽

Membrane Vesicles ◽

Outer Membrane Vesicles ◽

Multi Drug Resistance ◽

Gram Negative Bacteria ◽

Membrane Channels ◽

Gram Negative ◽

Electrophysiological Characterization

Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we extract, purify and reconstitute them into artificial planar membranes. To avoid this time-consuming procedure, here we show a robust approach using fusion of native outer membrane vesicles (OMV) into planar lipid bilayer which moreover allows also to some extend the characterization of membrane protein channels in their native environment. Two major membrane channels from Escherichia coli, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion revealed surprisingly single or only few channel activities. The asymmetry of the OMV´s translates after fusion into the lipid membrane with the LPS dominantly present at the side of OMV addition. Compared to conventional reconstitution methods, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution. The addition of Enrofloxacin on the LPS side yields somewhat higher association (kon) and lower dissociation (koff) rates compared to LPS-free reconstitution. We conclude that using outer membrane vesicles is a fast and easy approach for functional and structural studies of membrane channels in the native membrane.

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Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

Current Bioactive Compounds ◽

10.2174/1573407215666190124115010 ◽

2020 ◽

Vol 16 (4) ◽

pp. 481-488

Author(s):

Heli Sanghvi ◽

Satyendra Mishra

Keyword(s):

Antibacterial Activity ◽

Gram Negative Bacteria ◽

Pyrazole Derivatives ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Curcumin Derivatives ◽

Structure Activity ◽

Electron Donating Groups ◽

Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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