Biosynthesis of silver nanoparticles using Pergularia daemia (Hamilton, 1822) leaf extract and its enhanced antibacterial activity against gram negative bacteria (Escherichia coli)

2020 ◽  
Author(s):  
M. Lekeshmanaswamy ◽  
K. Anusiyadevi
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Leaf Extract ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals Green Synthesis, Antioxidant and Antimicrobial Activity of Silver Nanoparticles Using Gnetum africanum Extracts

2021 ◽  
pp. 1-7
Author(s):  
I. M. Uneze ◽  
J. O. Otonko ◽  
A. K. Adigun ◽  
S. J. Adebayo
Keyword(s):  
Escherichia Coli ◽  
Aqueous Solution ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Leaf Extract ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria

The synthesis and application of nanoparticles is an important area of research that is gaining attention recently. In this recent project, we report the synthesis of silver nanoparticles, AgNP using aqueous solution of silver nitrate and Gnetum africanum leaf extract (reducing agent). The synthesis of AgNP was achieved by mixing aqueous solution of silver nitrate (70ml, 15.75mM) with a solution of Gnetum africanum leaf extract 100 ml) in a reaction flask and allowed to stand for 24 hours in a dark cupboard. A color change from light brown to yellowish brown was observed which indicated that synthesis of silver nanoparticles took place. The presence of AgNP was ascertained using UV-vis spectra analysis and absorption at 442 nm showed the presence of AgNP. The antioxidant assay of both the synthesized AgNP and the leaf extract was determined using DPPH. Antimicrobial activity was conducted using three different organisms which were Staphylococcus aureus, Escherichia coli and Pseudomonas respectively. The antioxidant results using DPPH scavenging ability of AgNp showed that at concentrations of 2mg/ml,1mg/ml and 0.1mg/ml, the percentage inhibition  of  DPPH  by AgNp was 61.69, 53.06 and 38.31 respectively and that of Gnetum africanum leaf extract was 81.32, 78.49, and 58.29 respectively at the same concentrations using Ascorbic acid as a standard. The antimicrobial activity of both the synthesized AgNps and Gnetum Africanum Leaf extract using one gram positive bacteria (Staphylococcus aureus) and two gram negative bacteria (Escherichia coli and Pseudomonas) revealed that the synthesized AgNps showed lesser activity than Gnetumafricanum leaf extract for both the gram positive bacteria (Staphylococcus aureus) and gram negative bacteria (Pseudomonas) and (Escherichia coli). From the above findings, it can be observed that Gnetum Africanum Leaf extract reduced Ag+ to Ag0 and also both the synthesized AgNps and the Gnetum Africanum Leaf extract showed reasonable antioxidant activity against DPPH and antimicrobial activity against the tested microorganisms. This implied that both samples have medicinal values.

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 A Study on Antibacterial Activity of Silver Nanoparticles

2018 ◽  
Vol 29 (2) ◽  
pp. 37-41
Author(s):  
M Iqbal Hossain ◽  
M Anwar Habib ◽  
Nazimuddin Ahmed
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Antibacterial Effect ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Reference Drug ◽  
Gram Negative ◽  
Quasi Experimental

This quasi experimental study was designed to evaluate antibacterial activity of chemically synthesized silver nanoparticles (AgNPs) from silver nitrate (AgNO3) solutions on gram negative bacteria like E.Coli using disc diffusion method. Different concentrations of AgNPs, AgNO3 and reference drug ciprofloxacin were used to find out the antibacterial activity which revealed that AgNPs possessed significant antibacterial effect compared to AgNO3 solutions but relatively less antibacterial effect than that of ciprofloxacin. So chemical synthesis guided AgNPs may have some antibacterial effects.TAJ 2016; 29(2): 37-41

scholarly journals Green Synthesis of Silver Nanoparticles Using Novel Launaea Procumbens Leaves Extract and Screening Its Antibacterial Activity

2021 ◽  
Author(s):  
Sanjay Ratan Kumavat ◽  
SATYENDRA MISHRA
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Gram Negative Bacteria ◽  
Zone Of Inhibition ◽  
Gram Negative ◽  
Green Synthesized Silver Nanoparticles ◽  
Launaea Procumbens

Abstract Plants are emerging as a cost-effective and ecofriendly method for green synthesis of nanoparticles. The plant extract Launaea procumbens was used as a reduction agent in the green synthesis of silver nanoparticles. UV-Visible spectroscopy, HR-TEM, SAED, FE-SEM, EDAX, DLS, and FT-IR were used to study the green synthesized silver nanoparticles. UV-Vis spectroscopy of a prepared silver solution revealed maximum absorption at 435 nm. The synthesized silver nanoparticles were found to be spherical in shape with a size in the range of 24.28 to 31.54 nm. DLS analysis was used to determine the size of the green synthesized silver nanoparticles, which showed outstanding antibacterial action against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, as well as Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Gram-positive Bacillus subtilis had a maximum zone of inhibition of 20 mm, Staphylococcus aureus had a zone of inhibition of 19 mm, and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa had zones of inhibition of 13 mm.

scholarly journals Bioactivity of Isostructural Hydrogen Bonding Frameworks Built from Pipemidic Acid Metal Complexes

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2374
Author(s):  
Paula C. Alves ◽  
Patrícia Rijo ◽  
Catarina Bravo ◽  
Alexandra M. M. Antunes ◽  
Vânia André
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Drug Resistance ◽  
Antibacterial Activity ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Artemia Salina ◽  
Gram Negative Bacteria ◽  
Pipemidic Acid ◽  
Gram Negative

We report herein three novel complexes whose design was based on the approach that consists of combining commercially available antibiotics with metals to attain different physicochemical properties and promote antimicrobial activity. Thus, new isostructural three-dimensional (3D) hydrogen bonding frameworks of pipemidic acid with manganese (II), zinc (II) and calcium (II) have been synthesised by mechanochemistry and are stable under shelf conditions. Notably, the antimicrobial activity of the compounds is maintained or even increased; in particular, the activity of the complexes is augmented against Escherichia coli, a representative of Gram-negative bacteria that have emerged as a major concern in drug resistance. Moreover, the synthesised compounds display similar general toxicity (Artemia salina model) levels to the original antibiotic, pipemidic acid. The increased antibacterial activity of the synthesised compounds, together with their appropriate toxicity levels, are promising outcomes.

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 Green Synthesis of Gold and Silver Nanoparticles by Using Amorphophallus paeoniifolius Tuber Extract and Evaluation of Their Antibacterial Activity

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4773
Author(s):  
S. M. Abu Nayem ◽  
Nasrin Sultana ◽  
Md. Aminul Haque ◽  
Billal Miah ◽  
Md. Mahmodul Hasan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
Inhibitory Effect ◽  
Reducing Agent ◽  
Gram Negative Bacteria ◽  
Gold And Silver Nanoparticles ◽  
Gram Negative ◽  
X Ray ◽  
Tuber Extract

In this report, we discussed rapid, facile one-pot green synthesis of gold and silver nanoparticles (AuNPs and AgNPs) by using tuber extract of Amorphophallus paeoniifolius, and evaluated their antibacterial activity. AuNPs and AgNPs were synthesized by mixing their respective precursors (AgNO3 and HAuCl4) with tuber extract of Amorphophallus paeoniifolius as the bio-reducing agent. Characterization of AuNPs and AgNPs were confirmed by applying UV-vis spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS). From UV-vis characterization, surface plasmon resonance spectra were found at 530 nm for AuNPs and 446 nm for AgNPs. XRD data confirmed that both synthesized nanoparticles were face-centered cubic in crystalline nature, and the average crystallite sizes for the assign peaks were 13.3 nm for AuNPs and 22.48 nm for AgNPs. FTIR data evaluated the characteristic peaks of different phytochemical components of tuber extract, which acted as the reducing agent, and possibly as stabilizing agents. The antibacterial activity of synthesized AuNPs and AgNPs were examined in Muller Hinton agar, against two Gram-positive and four Gram-negative bacteria through the disc diffusion method. AuNPs did not show any inhibitory effect, while AgNPs showed good inhibitory effect against both Gram-positive and Gram-negative bacteria.

scholarly journals Synthesis of Some Derivatives of 4-phenyl-1,3-dihydro-2H-imidazole-2-thion Using Ionic Liquid as Catalyst and Evaluation of Their Antimicrobial Activity

2017 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
Bahareh Behmaram ◽  
Naser Foroughifar ◽  
Neda Foroughifar ◽  
Sara Hallajian
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Ionic Liquid ◽  
13C Nmr Spectroscopy ◽  
Basic Medium ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Derivatives Of ◽  
And Staphylococcus Aureus

The synthesis of some 1,3-diazoles and thiazoles was realized in different conditions:a) In the presence of PTSA or sulfuric acid as catalyst we obtained only diazole products(4a-d).b) In basic medium such as DABCO or sodium hydroxide and ionic liquid afforded thiazoles.c) Both products, diazoles and thiazoles were collected when using methanol as catalyst and solvent.All structures were confirmed by IR, 1H NMR and 13C NMR spectroscopy. The antibacterial activity of some synthesized compounds was investigated against Escherichia Coli (ATCC: 25922) and Serratia marcescens (ATCC: 13880) as gram negative bacteria, Bacillus sabtilis (ATCC: 6633) and Staphylococcus aureus (ATCC: 6338) as gram positive bacteria. Some of these products exhibit good activities to significant antibacterial activity.

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