Antibacterial Effects of Quinazolin-4(3H)-One Functionalized-Conjugated Silver Nanoparticles

Infections due to multi-drug resistant bacteria are on the rise and there is an urgent need to develop new antibacterials. In this regard, a series of six functionally diverse new quinazolinone compounds were synthesized by a facile one-pot reaction of benzoic acid derivatives, trimethoxymethane and aniline derivatives. Three compounds of 3-aryl-8-methylquinazolin-4(3H)-one, and 3-aryl-6,7-dimethoxyquinazolin4(3H)-one were prepared and tested against multi-drug resistant bacteria. Furthermore, we determined whether conjugation with silver nanoparticles improved the antibacterial efficacy of these quinazolinone derivatives. The newly synthesized compounds were characterized by ultraviolet visible spectrophotometry (UV-vis), Zetasizer analysis, Fourier transform infrared spectroscopic methods (FT-IR), and scanning electron microscopy (SEM). Using bactericidal evaluation, effects were determined against selected Gram-negative and Gram-positive bacteria. Furthermore, cytotoxicity of nanoconjugates on human cells were determined. The UV-vis spectrum of silver nanoparticles conjugated quinazolinone displayed surface plasmon resonance band in the range of 400–470 nm, and the size of nanoparticles was detected to be in the range of 100–250 nm by dynamic light scattering (DLS). FT-IR study confirmed the stabilization of silver nanoparticles by the presence of diverse functional arayl on each compound. SEM further revealed the construction of spherical nanoparticles. Among the quinazolinone derivative tested, two compounds (QNZ 4, QNZ 6) conjugated with silver nanoparticles showed enhanced antibacterial activity against Escherichia coli K1, Streptococcus pyogenes, Klebsiella pneumoniae, B. cereus and P. aeruginosa as compared to the compounds.

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Synthesis of silver nanoparticles using Nigella sativa seed extracts and assessment of their antibacterial activity

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11i2.2248 ◽

2020 ◽

Vol 11 (2) ◽

pp. 2525-2532

Author(s):

Sheik Shehensha ◽

Jyothi M V

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Activity ◽

Streptococcus Pyogenes ◽

Nigella Sativa ◽

Resistant Bacteria ◽

Drug Resistant ◽

Drug Resistant Bacteria ◽

Resistant Strains ◽

Nigella Sativa Seed ◽

Seed Extracts

Silver nanoparticles were biosynthesized from Nigella sativa seed extracts using ethanol and chloroform. The antibacterial activity of silver nanoparticles against some drug-resistant bacteria has been established, but further study is needed to assess whether these particles could be an option for the treatment and prevention of drug-resistant microbial infections. Synthesized nanoparticles were characterized and screened for their antibacterial properties on resistant strains. The biosynthesized silver nanoparticles were characterized by UV-Visible, FTIR, Dynamic light scattering and Scanning Electron Microscope (SEM) analysis. The antibacterial action of biosynthesized silver nanoparticles was assessed by Microtitre Broth dilution process using Ciprofloxacin as standard, against resistant strains like Pseudomonas aeruginosa, Clostridium difficile, Klebsiella pneumoniae and Streptococcus pyogenes. The Silver nanoparticles obtained from chloroform extract of Nigella sativa seeds were more effective against Pseudomonas aeuruginosa, Clostridium difficile and Streptococcus pyogenes; than ethanolic seed extracts at 120 µL. Our data propose that the silver nanoparticles are effective against a variety of drug-resistant bacteria, which makes them a potential candidate for use in pharmaceutical products that may help to treat drug-resistant pathogens in different clinical environments. The present study focuses on the ability of phytoconstituents capped with silver nitrate can be used to treat infections caused by resistant bacteria

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Conjugation of Silver Nanoparticles with De Novo Engineered Cationic Antimicrobial Peptides: Proposal for Study (Preprint)

10.2196/preprints.28307 ◽

2021 ◽

Author(s):

Alvin Hu

Keyword(s):

Antimicrobial Activity ◽

Silver Nanoparticles ◽

Minimum Inhibitory Concentration ◽

Antimicrobial Peptides ◽

Inhibitory Concentration ◽

De Novo ◽

Resistant Bacteria ◽

Drug Resistant ◽

Cationic Antimicrobial Peptides ◽

Drug Resistant Bacteria

BACKGROUND Cationic antimicrobial peptides have broad antimicrobial activity and provide a novel way of targeting multi drug resistant bacteria in an era of increasing antimicrobial resistance. Current developments show positive prospects for both antimicrobial peptides and silver nanoparticles individually. OBJECTIVE The primary objective is to propose another method of enhancing antimicrobial activity by conjugating silver nanoparticles with cationic antimicrobial peptides for a subsequent preliminary assessment on studying the minimum inhibitory concentration of multi drug resistant bacteria. The secondary objective would be to evaluate the safety of the conjugated compound to assess viability for in vivo use. METHODS The proposition is planned for approximately 3 overarching stages. Firstly, I propose synthesis of wlbu2c, a modified version of antimicrobial peptide wlbu2 with an added cysteine group, using standard Fmoc procedure. This will subsequently be attempted to stably conjugate with silver nanoparticles ideally through photochemical means. Secondly, the conjugate wlbu2c-AgNP will be tested for antimicrobial activity following Clinical & Laboratory Standards Institute Manual on standard minimum inhibitory concentration testing. If all of the above is completed the experiment can progress to the assessment of cytotoxicity using cell lysis assays. RESULTS I-TASSER simulation revealed that our modified peptide wlbu2c has similar secondary structure to original wlbu2 peptide. No other results have been obtained at this time other than aforementioned theoretical propositions. CONCLUSIONS The addition of silver nanoparticles to already developing de novo engineered antimicrobial peptides provide a second degree of freedom toward the development of potent antimicrobials. Future prospects include emergency last line therapy, treatment for current difficult to eradicate bacterial colonization such as in cystic fibrosis, implantable medical devices, cancer and immunotherapy. This proposal is intended to be provided to the public as I do not anticipate funding at this time.

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Aminonitrones as highly reactive bifunctional synthons. An expedient one-pot route to 5-amino-1,2,4-triazoles and 5-amino-1,2,4-oxadiazoles – potential antimicrobials targeting multi-drug resistant bacteria

New Journal of Chemistry ◽

10.1039/c9nj04529e ◽

2019 ◽

Vol 43 (44) ◽

pp. 17358-17366 ◽

Cited By ~ 1

Author(s):

Mikhail V. Il’in ◽

Alexandra A. Sysoeva ◽

Dmitrii S. Bolotin ◽

Alexander S. Novikov ◽

Vitalii V. Suslonov ◽

...

Keyword(s):

Resistant Bacteria ◽

Drug Resistant ◽

One Pot ◽

Mild Conditions ◽

Drug Resistant Bacteria ◽

Reaction Proceeds

A four-component one-pot reaction proceeds very rapidly under mild conditions and gives the heterocyclic systems in good yields.

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The interplay between size and valence state on the antibacterial activity of sub-10 nm silver nanoparticles

Nanoscale Advances ◽

10.1039/c9na00017h ◽

2019 ◽

Vol 1 (6) ◽

pp. 2365-2371 ◽

Cited By ~ 6

Author(s):

Hanif Haidari ◽

Nirmal Goswami ◽

Richard Bright ◽

Zlatko Kopecki ◽

Allison J. Cowin ◽

...

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Activity ◽

Valence State ◽

Antibacterial Effect ◽

Resistant Bacteria ◽

Drug Resistant ◽

Drug Resistant Bacteria

The interplay between size and valence state in ∼3 nm silver nanoparticles resulted in the highest antibacterial effect against multi-drug resistant bacteria.

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