scholarly journals 5-Bromo-1-(4-chlorobenzyl)-1H-indole-2-carboxamides as new potent antibacterial agents

2018 ◽  
Vol 24 (6) ◽  
pp. 327-332 ◽  
Author(s):  
Yogesh D. Mane ◽  
Smita S. Patil ◽  
Dhanraj O. Biradar ◽  
Bhimrao C. Khade
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Internal Standards ◽  
Gram Negative ◽  
E Coli ◽  
High Antibacterial Activity

Abstract Ten 5-bromoindole-2-carboxamides were synthesized, characterized and evaluated for antibacterial activity against pathogenic Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella Typhi using gentamicin and ciprofloxacin as internal standards. Compounds 7a–c, 7g and 7h exhibit high antibacterial activity with a minimum inhibitory concentration (MIC) of 0.35–1.25 μg/mL. Compounds 7a–c exhibit antibacterial activities that are higher than those of the standards against E. coli and P. aeruginosa.

scholarly journals Oxidative Stress and Antimicrobial Activity of Chromium(III) and Ruthenium(II) Complexes onStaphylococcus aureusandEscherichia coli

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina L. Páez ◽  
Claudia M. Bazán ◽  
María E. Bongiovanni ◽  
Judith Toneatto ◽  
Inés Albesa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Diimine Ligands

The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. The main aim of this work was to establish the potential of the syntheticα-diimine chromium(III) and ruthenium(II) complexes (where theα-diimine ligands are bpy = 2,2-bipyridine, phen = 1,10-phenanthroline, and dppz = dipyrido[3,2-a:2′,3′-c]-phenazine) like [Cr(phen)3]3+, [Cr(phen)2(dppz)]3+, [Ru(phen)3]2+, and [Ru(bpy)3]2+as antibacterial agents by generating oxidative stress. The [Cr(phen)3]3+and [Cr(phen)2(dppz)]3+complexes showed activity against Gram positive and Gram negative bacteria with minimum inhibitory concentrations (MICs) ranging from 0.125 μg/mL to 1 μg/mL, while [Ru(phen)3]2+and [Ru(bpy)3]2+do not exhibit antimicrobial activity against the two bacterial genera studied at the concentration range used. When ciprofloxacin was combined with [Cr(phen)3]3+for the inhibition ofStaphylococcus aureusandEscherichia coli, an important synergistic effect was observed, FIC 0.066 forS. aureusand FIC 0.064 forE. coli. The work described here shows that chromium(III) complexes are bactericidal forS. aureusandE. coli. Our results indicate thatα-diimine chromium(III) complexes may be interesting to open new paths for metallodrug chemotherapy against different bacterial genera since some of these complexes have been found to exhibit remarkable antibacterial activities.

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

scholarly journals Antibacterial Activity of Murrayaquinone A and 6-Methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Biswanath Chakraborty ◽  
Suchandra Chakraborty ◽  
Chandan Saha
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Naturally Occurring

The antibacterial activity of Murrayaquinone A (10), a naturally occurring carbazoloquinone alkaloid, and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione (11), a synthetic carbazoloquinone, both obtained during the development of the synthesis of Carbazomycin G, having unique quinone moiety, was studied against Gram-positive (Bacillus subtilisandStaphylococcus aureus) and Gram-negative (Escherichia coliandPseudomonassp.) bacteria. Compound10showed antibacterial activities against both ofEscherichia coliandStaphylococcus aureuswhereas compound11indicated the activity againstStaphylococcus aureusonly. Both compounds10and11exhibited minimum inhibitory concentration (MIC) of 50 μg mL−1againstStaphylococcus aureus.

scholarly journals Evaluation of Antibacterial Activity of Three Quaternary Ammonium Disinfectants on Different Germs Isolated from the Hospital Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Amal Ramzi ◽  
Bouchra Oumokhtar ◽  
Yassine Ez zoubi ◽  
Touria Filali Mouatassem ◽  
Moussa Benboubker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Quaternary Ammonium ◽  
Inhibitory Concentration ◽  
Hospital Environment ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

Background. The microbiological risk of the hospital environment, including inert surfaces, medical devices, and equipment, represents a real problem. Objective. This study is aimed at demonstrating and assessing the antibacterial activity of three synthetic disinfectants classified as quaternary ammoniums on different bacterial strains (Gram-negative and Gram-positive like Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus) isolated from the hospital environment. The reference strains included Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853 used as negative control strains. Method. Three quaternary ammonium disinfectants were tested: DDN9® (0.5%) which contains didecylmethylpolyoxyethylammonium propionate as an active substance, spray (0.4%) containing quaternary ammonium compounds, and Phagosurf ND® (0.4%) with didecyldimethylammonium chloride. Their effect was evaluated using the disk diffusion technique and the broth dilution methods, allowing the Minimum Inhibitory Concentration (MIC) and then the Minimum Bactericidal Concentration (MBC). Result. Only the growth of Gram-positive bacteria and some strains of Gram-negative bacteria were inhibited by the three synthetic disinfectants. NDD9® demonstrated an antibacterial effect only against the Gram-positive strains (S. aureus and S. aureus ATCC 29213) with a MIC of 0.25 mg/ml. The disinfectant spray showed effect against all four strains including E. coli (9), S. aureus, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 with an inhibitory concentration of 4 mg/ml, while the growth of S. aureus ATCC 29213 was inhibited at 2 mg/ml. The third disinfectant, Phagosurf ND®, inhibited only the growth of S. aureus ATCC 29213 at a MIC of 4 mg/ml. Conclusion. This study is the first here in Morocco to evaluate the bacterial activity of products intended for the control of the healthcare environment. The results obtained on the three disinfectants tested reveal an ineffectiveness against some isolated strains from the hospital environment.

scholarly journals Antibacterial Activity of Borassus flabellifer Vinegar-Graphene Quantum Dots Against Gram-Positive and Gram-Negative Bacteria

2021 ◽  
Vol 33 (11) ◽  
pp. 2662-2666
Author(s):  
Amnuay Noypha ◽  
Paweena Porrawatkul ◽  
Nongyao Teppaya ◽  
Parintip Rattanaburi ◽  
Saksit Chanthai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Antibacterial Activity ◽  
Graphene Quantum Dots ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

Borassus flabellifer vinegar–graphene quantum dots (BFV-GQDs) were successfully synthesized using a pyrolysis method with Borassus flabellifer vinegar (BFV) as the precursor. All the samples were characterized using ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The antibacterial activities of BFV-GQDs against strains of Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) were determined using the agar well diffusion method for preliminary screening, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth macro-dilution method. The zones of inhibition were compared with those of citric acid–graphene quantum dots (CA-GQDs). It was observed that the synthesized BFV-GQDs demonstrated excellent antibacterial activity against Staphylococcus aureus (82.3%) and good antibacterial activity against Escherichia coli (73.3%). The MIC of BFV-GQDs against E. coli was 6.25 mg/mL and S. aureus was 12.5 mg/mL, whereas the MBC of BFV-GQDs against E. coli was 12.5 mg/mL and S. aureus was 25.0 mg/mL.

scholarly journals Photodynamic antimicrobial chemotherapy with cationic phthalocyanines against Escherichia coli planktonic and biofilm cultures

RSC Advances ◽  
2017 ◽  
Vol 7 (65) ◽  
pp. 40734-40744 ◽  
Author(s):  
Min Li ◽  
Bingjie Mai ◽  
Ao Wang ◽  
Yiru Gao ◽  
Xiaobing Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Chemotherapy ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Photodynamic Antimicrobial Chemotherapy

Cationic phthalocyanines (Pcs) combine with photodynamic antimicrobial chemotherapy (PACT) presents excellent antibacterial activity to Gram-negative bacteriaE. coli.

scholarly journals The Target of Daptomycin Is Absent from Escherichia coli and Other Gram-Negative Pathogens

2012 ◽  
Vol 57 (1) ◽  
pp. 637-639 ◽  
Author(s):  
Christopher P. Randall ◽  
Katherine R. Mariner ◽  
Ian Chopra ◽  
Alex J. O'Neill
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Resistance Mechanisms ◽  
Efflux Transporters ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Intrinsic Resistance ◽  
Gram Negative ◽  
Content Type ◽  
E Coli

ABSTRACTAntistaphylococcal agents commonly lack activity against Gram-negative bacteria likeEscherichia coliowing to the permeability barrier presented by the outer membrane and/or the action of efflux transporters. When these intrinsic resistance mechanisms are artificially compromised, such agents almost invariably demonstrate antibacterial activity against Gram negatives. Here we show that this is not the case for the antibiotic daptomycin, whose target appears to be absent fromE. coliand other Gram-negative pathogens.

scholarly journals SINTESIS NANOPARTIKEL KOBALT FERRIT (CoFe2O4) MENGGUNAKAN EKSTRAK DAUN BINAHONG (Anredera cordifolia (Ten) Steenis) DAN APLIKASINYA SEBAGAI ANTIBAKTERI

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Charissa L. Luntungan ◽  
Henry F. Aritonang ◽  
Vanda S. Kamu
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Leaf Extract ◽  
Antibacterial Activities ◽  
Clear Zone ◽  
Cofe2o4 Nanoparticles ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria

ABSTRAKTelah dilakukan penelitian mengenai sintesis nanopartikel CoFe2O4 menggunakan ekstrak daun binahong (Anredera cordifolia (Ten) Steenis). dengan variasi perbandingan mol (Co(NO3)2.6H2O) : (Fe(NO3)3.9H2O) = 1:1 dalam 15 mL. Nanopartikel tersebut dikarakterisasi menggunakan XRD dan SEM serta diuji aktivitas antibakterinya. Uji aktivitas antibakteri mengunakan bakteri Staphylococcus aureus (gram-positif) dan Escherichia coli (gram-negatif). Hasil penelitian menunjukan bahwa ukuran nanopartikelnya adalah 37,52 nm. Kemudian aktivitas antibakteri diketahui berdasarkan luasnya zona bening yang terbentuk dengan hasil diperoleh sebesar 15 mm untuk bakteri E.coli dan 20 mm untuk bakteri S.aureus. Daun Binahong sendiri memiliki sifat sebagai antibakteri dengan hasil yang didapat adalah 8,25 mm untuk bakteri E.coli  dan 10,25 mm untuk bakteri S.aureus. Hal ini menunjukan bahwa nanopartikel CoFe2O4 1 : 1 dalam 15 mL ekstrak dapat digunakan sebagai antibakteriABSTRACTIt has been done research on the synthesis of CoFe2O4 nanoparticles using binahong (Anredera cordifolia (Ten) Steenis) leaf extract. With comparison mol variation of (Co(NO3)2.6H2O) : (Fe(NO3)3.9H2O) = 1:1 in 15 mL extract. The nanoparticles were characterized using XRD and SEM and tested for their antibacterial activities. Test antibacterial activity using Staphylococcus aureus (gram-positive) bacteria and Escherichia coli (gram-negative). The results showed that the nanoparticle size was 37.52 nm. Antibacterial activity is known by the extent of the clear zone formed with the results obtained by 15 mm for the E. coli bacteria and 20 mm for the bacteria S. aureus. The leaf Binahong itself has a trait as an antibacterial with the results obtained is 8.25 mm for the bacteria E. coli and 10.25 mm for the S.aureus bacteria. This suggests that the CoFe2O4 nanoparticles 1:1 mol in 15 mL extrack are used as antibacterial. 

scholarly journals Antibacterial Activity of Non-Cytotoxic, Amino Acid-Modified Polycationic Dendrimers against Pseudomonas aeruginosa and Other Non-Fermenting Gram-Negative Bacteria

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1818 ◽  
Author(s):  
Anna Maria Schito ◽  
Silvana Alfei
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Eukaryotic Cells ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Resistance Rates ◽  
New Compounds

Due to the rapid increase of antimicrobial resistance with ensuring therapeutic failures, the purpose of this study was to identify novel synthetic molecules as alternatives to conventional available, but presently ineffective antibiotics. Variously structured cationic dendrimers previously reported have provided promising outcomes. However, the problem of their cytotoxicity towards eukaryotic cells has not been completely overcome. We have now investigated the antibacterial activities of three not cytotoxic cationic dendrimers (G5Ds: G5H, G5K, and G5HK) against several multidrug-resistant (MDR) clinical strains. All G5Ds displayed remarkable activity against MDR non-fermenting Gram-negative species such as P. aeruginosa, S. maltophilia, and A. baumannii (MICs = 0.5–33.2 µM). In particular, very low MIC values (0.5–2.1 µM) were observed for G5K, which proved to be more active than the potent colistin (2.1 versus 3.19 µM) against P. aeruginosa. Concerning its mechanism of action, in time-killing and turbidimetric studies, G5K displayed a rapid non-lytic bactericidal activity. Considering the absence of cytotoxicity of these new compounds and their potency, comparable or even higher than that provided by the dendrimers previously reported, G5Ds may be proposed as promising novel antibacterial agents capable of overcoming the alarming resistance rates of several nosocomial non-fermenting Gram-negative pathogens.

scholarly journals Antibacterial activity of grapefruit peel extracts and green-synthesized silver nanoparticles

2021 ◽  
pp. 1330-1341
Author(s):  
Mbarga M. J. Arsène ◽  
I. V. Podoprigora ◽  
Anyutoulou K. L. Davares ◽  
Marouf Razan ◽  
M. S. Das ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Inhibitory Concentration ◽  
Antibacterial Properties ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Grapefruit Peel ◽  
Green Synthesized Silver Nanoparticles

Background and Aim: The gradual loss of efficacy of conventional antibiotics is a global issue. Plant material extracts and green-synthesized nanoparticles are among the most promising options to address this problem. Therefore, the aim of this study was to assess the antibacterial properties of aqueous and hydroalcoholic extracts of grapefruit peels as well as their inclusion in green-synthesized silver nanoparticles (AgNPs). Materials and Methods: Aqueous and hydroalcoholic extracts (80% v/v) were prepared, and the volume and mass yields were determined. The synthesis of AgNPs was done in an eco-friendly manner using AgNO3 as a precursor. The nanoparticles were characterized by ultraviolet–vis spectrometry and photon cross-correlation spectroscopy. The antibacterial activity of the extracts was tested on three Gram-positive bacteria (Staphylococcus aureus ATCC 6538, clinical Enterococcus faecalis, and S. aureus) and two Gram-negative bacteria (two clinical Escherichia coli) using various concentrations of extracts (100, 50, 25, 12, and 5 mg/mL and 5% dimethyl sulfoxide as negative control). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microdilution method. Modulation of cefazoline and ampicillin on resistant E. coli and S. aureus strains was added to the mixture design response surface methodology with extreme vertices design, with the diameters of inhibition and the fractional inhibitory concentration index as responses and factors, respectively. The antibiotic, the ethanolic extract, and water varied from 0.1 MIC to 0.9 MIC for the first two and from 0 to 0.8 in proportion for the third. Validating the models was done by calculating the absolute average deviation, bias factor, and accuracy factor. Results: The volume yield of the EE and aqueous extract (AE) was 96.2% and 93.8% (v/v), respectively, whereas their mass yields were 7.84% and 9.41% (m/m), respectively. The synthesized AgNPs were very uniform and homogeneous, and their size was dependent on the concentration of AgNO3. The antibacterial activity of the two extracts was dose-dependent, and the largest inhibition diameter was observed for the Gram-positive bacteria (S. aureus ATCC 6538; AE, 12; EE, 16), whereas AgNPs had a greater effect on Gram-negative bacteria. The MICs (mg/mL) of the AEs varied from 3.125 (S. aureus ATCC 6538) to 12.5 (E. coli 1 and E. coli 2), whereas the MICs of the EEs varied from 1.5625 (S. aureus 1, S. aureus ATCC 6538, and E. faecalis) to 6.25 (E. coli 1). There was a significant difference between the MICs of AEs and EEs (p=0.014). The MBCs (mg/mL) of the AEs varied from 12.5 (S. aureus ATCC 6538) to 50 (S. aureus 1), whereas those of the EEs varied from 6.25 (S. aureus 1) to 25 (E. coli 1 and E. faecalis). Ethanolic grapefruit extracts demonstrated an ability to modulate cefazolin on E. coli and S. aureus but were completely indifferent to ampicillin on E. coli. Conclusion: Grapefruit peel extracts and their AgNPs exhibit antibacterial properties that can be exploited for the synthesis of new antimicrobials and their EEs may be efficiently used synergistically with other antibiotics against bacteria with intermediate susceptibility.

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