scholarly journals New Hybrid Copper Nanoparticles/Conjugated Polyelectrolyte Composite with Antibacterial Activity

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 401
Author(s):  
Ignacio A. Jessop ◽  
Yasmín P. Pérez ◽  
Andrea Jachura ◽  
Hipólito Nuñez ◽  
Cesar Saldías ◽  
...  

In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic π-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs’ effect and, to a lesser extent, to the cationic CPE.

Proceedings ◽  
2021 ◽  
Vol 66 (1) ◽  
pp. 18
Author(s):  
Jessica Ribeiro ◽  
Vanessa Silva ◽  
Alfredo Aires ◽  
Rosa Carvalho ◽  
Gilberto Igrejas ◽  
...  

Multidrug-resistant bacteria are a significant threat to public health and new classes of antibiotics and approaches to treatment are needed. Several studies have shown that natural plant-derived compounds could be a promising mean to fight microbial resistance but only a few were conducted with antibiotic resistant bacteria. Therefore, the aim of this study was to extract phenolic compounds from the leaves, fruits, and tree trunk of Platanus hybrida and evaluate their antimicrobial activity against antibiotic resistant bacterial strains. The polyphenolic compounds were extracted using a water/ethanol (20:80) mixture. Two grams of powder of each sample was extracted with 100 mL of solvent by stirring for 2h. The extracts were redissolved in dimethyl sulfoxide (DMSO) to a final concentration of 100 mg/mL. An antimicrobial susceptibility assay was performed using the Kirby–Bauer disc diffusion method and was tested against ten different bacteria: Listeria monocytes, Bacillus cereus, Enterococcus faecium, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. The fruits had the highest antibacterial activity showing a minimum inhibitory concentration (MIC) of 10mg/mL, contrary to the tree trunk that showed the lowest antibacterial activity. None of the extracts showed antimicrobial properties against S. enteritidis, E. faecium and E. faecalis. These results show that P. hybrida’s phenolic compounds act as antibacterial agents, which may become useful therapeutic tools and represent a source for the development of novel antimicrobials. However, they were not effective against all bacteria, which shows that polyphenols alone might not substitute antibiotics.


2018 ◽  
Vol 16 (5) ◽  
pp. 341-348
Author(s):  
On-Anong SOMSAP

Antibiotic resistance bacteria has become an increasing problem now today due to many factors. This study investigates the efficacy of Prismatomeris tetrandra K. Schum root extract as a new source of antibacterial activity for antibiotic resistant bacteria using agar well diffusion method. The results showed that S. aureus TISTR517 exhibited more sensitivity to P. tetrandra K. Schum root extract than other Gram-positive bacteria indicator strains. On the other hand, Gram-negative bacteria exhibited resistance to P. tetrandra K. Schum root extract. The study further showed the activity between P. tetrandra K. Schum root extract and gentamycin (10 µg), it revealed that MRSA142 was resistant to gentamycin (10µg) but sensitive to P. tetrandra K. Schum root extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was evaluated by using S. aureus TISTR517 and MRSA142 as indicator strains. The MIC value was 0.59 mg/mL and 1.17 mg/mL for S. aureus TISTR517 and MRSA142, respectively. MBC assay demonstrated that the MBC value was 9.75 mg/mL and 150 mg/mL for S. aureus TISTR517 and MRSA142 respectively. The mode of action was investigated with the presence of P. tetrandra K. Schum root extract in the culture broth. The action of P. tetrandra K. Schum root extract was revealed of bacteriostatic activity due to the Optical density (OD) at 600 nm and Colony-Forming Units (CFU) of indicator strains were continuously decreased.


Author(s):  
Srijan Sunar ◽  
Rajeshkumar S ◽  
Anitha Roy ◽  
Lakshmi T

Copper nanoparticles makes important progress in the area of nanotechnology and nanomedicine due to their good optical, electrical and anti-fungal/bacterial application. It is prepared using some methods such as vacuum vapour deposition, microwave irradiation methods, chemical reduction and laser ablation. The chemical reduction method is simple, inexpensive and gives a liable control of geometrical nanoparticle characteristics like size and shape. 20 millimolar of 80 ml copper sulphate prepared using double distilled water. The plant extract is added with the metal solution and was made into 100 ml solution. The synthesised nanoparticles solution is preliminarily characterized by using UV- vis-spectroscopy, 3ml of the solution is taken in curette and scanned in double beam UV-vis- spectrophotometer from 300 nm to 700 nm wavelength. The agar well diffusion method is used. Different concentration of Cu NPs was tested against Staphylococcus aureus, Streptococcus mutans (gram +), Enterococcus sp and Pseudomonas sp. The result reveals that Moringa Oleifera mediated with copper nanoparticles show effective antibacterial activity. CuNPs ex significantly higher activity with an increase in the zone of inhibition diameter. The plant extract is observed to be dark green, and the copper nanoparticles are seen to be in light greenish in colour. They can be used in toothpaste and oral medicines due to their antibacterial activity. Nanoparticles are expected to be used in future for the effective drug systems and immunity against diseases.


2020 ◽  
Vol 11 (22) ◽  
pp. 5735-5739 ◽  
Author(s):  
Eunhye Lee ◽  
Xingshu Li ◽  
Juwon Oh ◽  
Nahyun Kwon ◽  
Gyoungmi Kim ◽  
...  

A boronic acid functionalized phthalocyanine displays aggregation-enhanced reactive oxygen species (ROS) generation and excellent photodynamic antibacterial activity.


Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 923
Author(s):  
Anette Garrido ◽  
Librada A. Atencio ◽  
Rita Bethancourt ◽  
Ariadna Bethancourt ◽  
Héctor Guzmán ◽  
...  

The present research aimed to evaluate the antibacterial activity of volatile organic compounds (VOCs) produced by octocoral-associated bacteria Bacillus sp. BO53 and Pseudoalteromonas sp. GA327. The volatilome bioactivity of both bacteria species was evaluated against human pathogenic antibiotic-resistant bacteria, methicillin-resistant Staphylococcus aureus, Acinetobacter baumanni, and Pseudomonas aeruginosa. In this regard, the in vitro tests showed that Bacillus sp. BO53 VOCs inhibited the growth of P. aeruginosa and reduced the growth of S. aureus and A. baumanni. Furthermore, Pseudoalteromonas sp. GA327 strongly inhibited the growth of A. baumanni, and P. aeruginosa. VOCs were analyzed by headspace solid-phase microextraction (HS-SPME) joined to gas chromatography-mass spectrometry (GC-MS) methodology. Nineteen VOCs were identified, where 5-acetyl-2-methylpyridine, 2-butanone, and 2-nonanone were the major compounds identified on Bacillus sp. BO53 VOCs; while 1-pentanol, 2-butanone, and butyl formate were the primary volatile compounds detected in Pseudoalteromonas sp. GA327. We proposed that the observed bioactivity is mainly due to the efficient inhibitory biochemical mechanisms of alcohols and ketones upon antibiotic-resistant bacteria. This is the first report which describes the antibacterial activity of VOCs emitted by octocoral-associated bacteria.


Nanoscale ◽  
2019 ◽  
Vol 11 (31) ◽  
pp. 14937-14951 ◽  
Author(s):  
Tao Huang ◽  
James A. Holden ◽  
Daniel E. Heath ◽  
Neil M. O'Brien-Simpson ◽  
Andrea J. O'Connor

Selenium nanoparticles (Se NPs) are a promising antibacterial agent to address the challenge of antibiotic resistant bacteria. In this work, the antibacterial activity of the spherical Se NPs was shown to be strongly size dependent.


2021 ◽  
Vol 16 (3) ◽  
pp. 91-95
Author(s):  
Surachai Rattanasuk ◽  
Rujirek Boongapim ◽  
Tannatorn Phiwthong

The aim of this study was to determine the antibacterial activity of Cathormion umbellatum extracts against seven antibiotic-resistant bacteria. The pods, leaves and branches of C. umbellatum were extracted with ethanol and methanol. The disc diffusion assay was used to screen the antibacterial activity and broth microdilution and colorimetric assay were used to measure the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. The result indicated that the highest inhibition zone (11 mm) was presented in ethanolic pods extract against multidrug resistance Klebsiella pneumoniae. The lowest MIC value of 0.05 mg/mL was obtained from branch extracted with ethanol against colistin resistant Pseudomonas aeruginosa. The lowest MBC values of 1.56 mg/mL were obtained when using C. umbellatum leaves extracted with methanol against all test antibiotic-resistant bacteria. This is the first report presented C. umbellatum extracts have the potential to eliminate antibiotic-resistant bacteria in patients. These findings show the antibacterial effect of C. umbellatum.


2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Andrew Melencion ◽  
◽  
Winson Gutierrez ◽  
Merced Melencion ◽  
◽  
...  

antimicrobial, nanoparticles, Musa acuminata × balbisiana


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Andresa Piacezzi Nascimento ◽  
Larissa Ariana Roveroni Moraes ◽  
Nathália Ursoli Ferreira ◽  
Gabriela de Padua Moreno ◽  
Fernanda Grassi Mangolini Uahib ◽  
...  

The alternative use of natural products, like royal jelly (RJ), may be an important tool for the treatment of infections caused by antibiotic-resistant bacteria. RJ presents a large number of bioactive substances, including antimicrobial compounds. In this study, we carried out the chemical characterization of fresh and lyophilized RJ and investigated their antibacterial effects with the purpose of evaluating if the lyophilization process maintains the chemical and antibacterial properties of RJ. Furthermore, we evaluated the antibacterial efficacy of the main fatty acid found in RJ, the 10-hydroxy-2-decenoic acid (10H2DA). Chromatographic profile of the RJ samples showed similar fingerprints and the presence of 10H2DA in both samples. Furthermore, fresh and lyophilized RJ were effective against all bacteria evaluated; that is, the lyophilization process maintains the antibacterial activity of RJ and the chemical field of 10H2DA. The fatty acid 10H2DA exhibited a good antibacterial activity againstStreptococcus pneumoniae. Therefore, it may be used as an alternative and complementary treatment for infections caused by antibiotic-resistantS. pneumoniae.


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