scholarly journals In vitro evaluation of antioxidant, biochemical and antimicrobial properties of biosynthesized silver nanoparticles against multidrug-resistant bacterial pathogens

2017 ◽  
Vol 31 (2) ◽  
pp. 373-379 ◽  
Author(s):  
Wael Mahmoud ◽  
Ahmed M. Elazzazy ◽  
Enas N. Danial
2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.


2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Emerson Danguy Cavassin ◽  
Luiz Francisco Poli de Figueiredo ◽  
José Pinhata Otoch ◽  
Marcelo Martins Seckler ◽  
Roberto Angelo de Oliveira ◽  
...  

2021 ◽  
Author(s):  
Jelena S. Katanić Stanković ◽  
◽  
Nikola Srećković ◽  
Vladimir Mihailović

In this study, silver nanoparticles (AgNPs) have been synthesized using the aqueous extract of the aerial parts of B. purpurocaerulea, collected in Serbia. B. purpurocaerulea silver nanoparticles (Bp– AgNPs) synthesis was confirmed using UV-Vis spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The biological potential of synthesized Bp-AgNPs was evaluated in vitro using ABTS assay for determining free radical scavenging potential and microdilution method for analysis of antimicrobial properties. Bp-AgNPs showed high antioxidant activity similar to Bp-extract, comparable to BHT. The synthesized nanoparticles exerted remarkable antibacterial effects, with minimal inhibitory concentration (MIC) values below 20 µg/mL. In the case of some bacterial strains, the results of Bp– AgNPs were comparable or similar to standard antibiotic erythromycin. The antifungal activity of Bp– AgNPs was moderate for most of the used strains. Nevertheless, several fungi were resistant to the NPs action, while two tested Penicillium species were extremely sensitive on Bp-AgNPs with MIC lower than 40 µg/mL. The antimicrobial properties of Bp-AgNPs can be useful for the development of new NPs-containing products.


Author(s):  
Shyla Marjorie Haqq ◽  
Amit Chattree

  This review is based on the synthesis of silver nanoparticles (AgNPs) using a green approach which is biofabricated from various medicinal plants. AgNPs were prepared from the various parts of the plants such as the flowers, stems, leaves, and fruits. Various physiochemical characterizations were performed using the ultraviolet (UV)-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy. AgNPs were also used to inhibit the growth of bacterial pathogens and were found to be effective against both the Gram-positive and Gram-negative bacteria. For the silver to have antimicrobial properties, it must be present in the ionized form. All the forms of silver-containing compounds with the observed antimicrobial properties are in one way or another source of silver ions. Although the antimicrobial properties of silver have been known, it is thought that the silver atoms bind to the thiol groups in enzymes and subsequently leads to the deactivation of enzymes. For the silver to have antimicrobial properties, it must be present in the ionized form. The study suggested that the action of the AgNPs on the microbial cells resulted into cell lysis and DNA damage. AgNPs have proved their candidature as a potential antibacterial against the multidrug-resistant microbes. The biological agents for synthesizing AgNPs cover compounds produced naturally in microbes and plants. Reaction parameters under which the AgNPs were being synthesized hold prominent impact on their size, shape, and application. Silver nanoparticle synthesis and their application are summarized and critically discussed in this review.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Mei X. Chen ◽  
Kenneth S. Alexander ◽  
Gabriella Baki

Background. Skin infections occur commonly and often present therapeutic challenges to practitioners due to the growing concerns regarding multidrug-resistant bacterial, viral, and fungal strains. The antimicrobial properties of zinc sulfate and copper sulfate are well known and have been investigated for many years. However, the synergistic activity between these two metal ions as antimicrobial ingredients has not been evaluated in topical formulations. Objective. The aims of the present study were to (1) formulate topical creams and gels containing zinc and copper alone or in combination and (2) evaluate the in vitro antibacterial activity of these metal ions in the formulations. Method. Formulation of the gels and creams was followed by evaluating their organoleptic characteristics, physicochemical properties, and in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus. Results. Zinc sulfate and copper sulfate had a strong synergistic antibacterial activity in the creams and gels. The minimum effective concentration was found to be 3 w/w% for both active ingredients against the two tested microorganisms. Conclusions. This study evaluated and confirmed the synergistic in vitro antibacterial effect of copper sulfate and zinc sulfate in a cream and two gels.


Author(s):  
Dahiya P

  Objective: The inhibitory properties of successive extracts from Dioscorea bulbifera (Dioscoreaceae) tubers have been evaluated for the presence of phytochemical constituents and antimicrobial efficacy against multidrug-resistant (MDR) clinical isolates was evaluated.Methods: The tuber of D. bulbifera was oven dried and extracted successively with n-hexane, chloroform, methanol, ethanol, and water. The antimicrobial potential of successive extracts against MDR isolates was studied by agar well-diffusion method. Qualitative phytochemical analysis was performed.Results: Qualitative phytochemical analysis demonstrated the presence of steroids, flavonoids, cardiac glycosides, saponins, and reducing sugars in almost all the extracts tested. Anthraquinones, phlobatanins, and tannins were not reported in any extracts tested. The in vitro antimicrobial activity of various solvents and water extracts of D. bulbifera was further investigated against ten MDR bacteria and three fungi, respectively. Aqueous and chloroform extracts were found to be more potent being capable of exerting significant inhibitory activities against the majority of the isolates such as Escherichia coli, Acinetobacter sp., Salmonella paratyphi, Klebsiella pneumoniae, and Candida albicans. The highest inhibitory activity was observed for K. pneumoniae with wide inhibition zone diameters (17 ± 0.15 mm), followed by E. coli 1(13 ± 0.11) mm, and Acinetobacter sp. (11 ± 0.12).Conclusion: Based on the present study, the extracts of D. bulbifera tubers have shown excellent activity against MDR microbial cultures tested. Further study is recommended for clinical evaluation, of the efficacy of crude extract in herbal medicine that can serve as a base for the development of novel potent drugs and phytomedicines.


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