Green synthesis of silver nanoparticles with Euphorbia tirucalli extract and its protection against microbial decay of strawberries during storage

Author(s):  
Shirlene Souza Oliveira ◽  
Gilberto Costa Braga ◽  
Noélle Khristinne Cordeiro ◽  
José Renato Stangarlin ◽  
Helton José Alves
2020 ◽  
Vol 21 (3) ◽  
pp. 206-218 ◽  
Author(s):  
Sadia Nazer ◽  
Saiqa Andleeb ◽  
Shaukat Ali ◽  
Nazia Gulzar ◽  
Tariq Iqbal ◽  
...  

Background: Multi-drug resistance in bacterial pathogens is a major concern of today. Green synthesis technology is being used to cure infectious diseases. Objectives: The aim of the current research was to analyze the antibacterial, antioxidant, and phytochemical screening of green synthesized silver nanoparticles using Ajuga bracteosa. Methods: Extract of A. bracteosa was prepared by maceration technique. Silver nanoparticles were synthesized using A. bracteosa extract and were confirmed by UV-Vis spectrophotometer, Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The antibacterial, anti-biofilm, cell proliferation inhibition, TLC-Bioautography, TLC-Spot screening, antioxidant, and phytochemical screening were also investigated. Results: UV-Vis spectrum and Scanning electron microscopy confirmed the synthesis of green nanoparticles at 400 nm with tube-like structures. FTIR spectrum showed that functional groups of nanoparticles have a role in capping and stability of AgNP. Agar well diffusion assay represented the maximum antibacterial effect of ABAgNPs against Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, and Pseudomonas aeruginosa at 0.10 g/mL concentration compared to ABaqu. Two types of interactions among nanoparticles, aqueous extract, and antibiotics (Synergistic and additive) were recorded against tested pathogens. Crystal violet, MTT, TLC-bio-autography, and spot screening supported the findings of the antibacterial assay. Highest antioxidant potential effect in ABaqu was 14.62% (DPPH) and 13.64% (ABTS) while 4.85% (DPPH) and 4.86% (ABTS) was recorded in ABAgNPs. Presence of phytochemical constituents showed pharmacological importance. Conclusion: It was concluded that green synthesis is an innovative technology in which natural products are conjugated with metallic particles and are used against infectious pathogens. The current research showed the significant use of green nanoparticles against etiological agents.


2017 ◽  
Vol 7 (1) ◽  
pp. 104-112 ◽  
Author(s):  
Alireza Ebrahiminezhad ◽  
Saeed Taghizadeh ◽  
Aydin Berenjian ◽  
Fatemeh Heidaryan Naeini ◽  
Younes Ghasemi

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1007
Author(s):  
Azam Ali ◽  
Mariyam Sattar ◽  
Fiaz Hussain ◽  
Muhammad Humble Khalid Tareen ◽  
Jiri Militky ◽  
...  

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of silver nanoparticles (Ag NPs) was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized Ag NPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) Ag NPs, capped with poly-tannic acid (Ag NPs-PTA). The average particle size of Ag NPs-PTA was found to be 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed to be stable for more than 15 months in the ambient environment (25 °C, 65% relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus (ZOI 3.0 mM) and Escherichia coli (ZOI 3.5 mM). Ag NPs-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s−1·mg−1. For comparison, bare Ag NPs show catalytic activity with a normalized rate constant of 139.78 mL·s−1·mg−1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The ultra-high catalytic and good antimicrobial properties can be attributed to the fine size and good aqueous stability of Ag NPs-PTA. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and medical.


AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susanna Gevorgyan ◽  
Robin Schubert ◽  
Mkrtich Yeranosyan ◽  
Lilit Gabrielyan ◽  
Armen Trchounian ◽  
...  

AbstractThe application of green synthesis in nanotechnology is growing day by day. It’s a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly’s potential in the green synthesis of silver nanoparticles and their antibacterial activity. Royal jelly served as a reducing and oxidizing agent in the green synthesis technology of colloidal silver nanoparticles. The UV–Vis maximum absorption at ~ 430 nm and fluorescence emission peaks at ~ 487 nm confirmed the presence of Ag NPs. Morphology and structural properties of Ag NPs and the effect of ultrasound studies revealed: (i) the formation of polydispersed and spherical particles with different sizes; (ii) size reduction and homogeneity increase by ultrasound treatment. Antibacterial activity of different concentrations of green synthesized Ag NPs has been assessed on Gram-negative S. typhimurium and Gram-positive S. aureus, revealing higher sensitivity on Gram-negative bacteria.


Author(s):  
Md. Abdullah Al Masud ◽  
Hamid Shaikh ◽  
Md. Shamsul Alam ◽  
M. Minnatul Karim ◽  
M. Abdul Momin ◽  
...  

Abstract Background The green synthesis strategy of metallic nanoparticles (NPs) has become popular due to being environmentally friendly. Stable silver nanoparticles (AgNPs) have been synthesized by natural products such as starch, soy protein, various extract of leaves, barks, and roots functioning both as reducing and stabilizing agents. Likewise, silk sericin (SS) is a globular protein discarded in the silk factory might be used for NP synthesis. In this research, we focus on the green synthesis and stabilization of AgNPs by SS as well as assessment of their antibacterial activities against some drug-resistant pathogen. Results SS was extracted from Bombyx mori silkworm cocoons in an aqueous medium. 17 w/w% of dry sericin powder with respect to the cocoon’s weight was obtained by freeze-drying. Furthermore, AgNPs conjugated to sericin, i.e., SS-capped silver nanoparticles (SS-AgNPs) were synthesized by easy, cost-effective, and environment-friendly methods. The synthesized SS-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction measurement. It has been found from the absorbance of UV-visible spectroscopy that a higher percent of SS-AgNPs was obtained at a higher concentration of silver nitrate solution. FTIR-ATR spectra showed that the carboxylate groups obtained from silk sericin act as a reducing agent for the synthesis of silver nanoparticles, while NH2+ and COO− act as a stabilizer of AgNPs. The X-ray diffractogram of SS-AgNPs was quite different from AgNO3 and sericin due to a change in the crystal structure. The diameter of AgNPs was around 20–70 nm observed using TEM. The synthesized SS-AgNPs exhibited strong antibacterial activity against multidrug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 20μg/mL. Conclusions This study encourages the use of Bombyx mori for the ecofriendly synthesis of SS-AgNPs to control multidrug-resistant microorganisms.


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