scholarly journals Green Synthesis of Silver Nanoparticles Using Grewia optiva Leaf Aqueous Extract and Isolated Compounds as Reducing Agent and Their Biological Activities

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Muhammad Iftikhar ◽  
Muhammad Zahoor ◽  
Sumaira Naz ◽  
Nausheen Nazir ◽  
Gaber El-Saber Batiha ◽  
...  

In this study, an attempt was made to synthesize silver nanoparticles (Ag-NPs) using Grewia optiva leaf extract and isolated compounds. The bioreductant capacity of Grewia optiva leaf extract for the synthesis of Ag-NPs was assessed using various confirmatory techniques like thermogravimetric analysis (TGA), particle size analysis (PSA), energy-dispersive X-ray (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and UV-Visible spectroscopy. The presence of various bioactive compounds in leaf aqueous extract was confirmed through HPLC analysis, and 8 compounds were identified among the different peaks present in the chromatogram. Biopotencies like antioxidant, antibacterial, and effect on hair growth were determined for extract and NPs. Antioxidant capacities were assessed through standard ABTS and DPPH methods. The antibacterial potential was evaluated in terms of zone of inhibition, minimum bactericidal concentration, and minimum inhibitory concentration of the Ag-NPs and the leaf extract against selected strains of bacteria, whereas the effect on growth of rabbit hair was studied through topical treatment for a specific period of time. Better antibacterial and DPPH and ABTS free radical inhibition was observed for the formulated Ag-NPs as compared to leaf extract. The previously isolated eight compounds from this plant’s chloroform and ethyl acetate extracts were also tested for their bioreductant capacities. Out of them, the highest amount of precipitates was obtained with compound VII ((2,5-dihydroxyphenyl)-3 ′ ,6 ′ ,8 ′ -trihydroxyl-4H-chromen-4 ′ -one). The study implies that the biogenically engineered nanoscale particles could have promising biological activities in comparison to parental extract and they need to be investigated further as potential therapeutic agents to be used as antibacterial and antioxidant agents and for hair growth enhancement.

Author(s):  
MONIKA GUPTA

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties.  Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria.


Author(s):  
B. Anandh ◽  
A. Muthuvel ◽  
M. Emayavaramban

The present investigation demonstrates the formation of silver nanoparticles by the reduction of the aqueous silver metal ions during exposure to the Lagenaria siceraria leaf extract. The synthesized AgNPs have characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. AgNPs formation has screened by UV-visible spectroscopy through colour conversion due to surface plasma resonance band at 427 nm. X-ray diffraction (XRD) confirmed that the resulting AgNPs are highly crystalline and the structure is face centered cubic (fcc). FT-IR spectrum indicates the presence of different functional groups present in the biomolecules capping the nanoparticles. Further, inhibitory activity of AgNPs and leaf extract were tested against human pathogens like gram-pastive (Staphylococcus aureus, Bacillus subtilis), gram-negative (Escherichia coli and Pseudomonas aeruginosa). The results indicated that the AgNPs showed moderate inhibitory actions against human pathogens than Lagenaria siceraria leaf extract, demonstrating its antimicrobial value against pathogenic diseases


2018 ◽  
Vol 7 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Ramesh Vinayagam ◽  
Thivaharan Varadavenkatesan ◽  
Raja Selvaraj

Abstract:An environmentally benign method to synthesize silver nanoparticles (SNPs) using the leaf extract ofBridelia retusawas developed. The UV-Vis absorption spectrum of the synthesized SNPs displayed a surface plasmon peak at 420 nm. Scanning electron microscopy (SEM) revealed the irregular shaped nanoparticles, and energy dispersive X-ray (EDX) ascertained the presence of metallic silver by showing a strong signal at 3 eV. The crystalline structure of metallic silver was confirmed by X-ray diffraction (XRD). The mean size of the SNPs was calculated as 16.21 nm. Fourier infrared (FT-IR) spectroscopic studies displayed specific bands for various functional groups and affirmed the function of reduction and stabilization of SNPs. The stability was endorsed by the zeta potential value of −18.1 mV. The results evidenced that this leaf extract-mediated synthesis method is eco-friendly, rapid, and cheap. The catalytic power of the SNPs was investigated for Rhodamine B dye degradation. The SNPs completely degraded Rhodamine B within 9 min; thus, the dye degradation process was very rapid. The pseudo-first order degradation constant was found out to be 0.1323 min−1. This paves the way for the future development of novel nano-catalysts to reduce environmental pollution.


Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Mahsa Eshghi ◽  
Hamideh Vaghari ◽  
Yahya Najian ◽  
Mohammad Najian ◽  
Hoda Jafarizadeh-Malmiri ◽  
...  

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.


2021 ◽  
Author(s):  
Vanaraj sekar

Abstract A simple and eco-friendly method for the green synthesis of silver nanoparticles (AgNPs) by ultrasound-assisted strategy using Barleria buxifolia leaf extract as a reducing and capping agent was established in this study. The obtained AgNPs were characterized. UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM and TEM), Energy Dispersive X-Ray Analyzer (EDX), X-ray diffraction, dynamic light scattering (DLS) analysis showed that the obtained AgNPs were mono dispersed spheres with uniform size of 80 nm. UV-vis spectroscopy, FTIR, and XRD analysis indicated that the surface of the obtained AgNPs was covered with organic molecules in plant extracts. The results of ABTS assays showed that high antioxidant activity was seen in the obtained AgNPs. Green synthesized AgNPs showed potent antibacterial and anti-biofilm activity against tested pathogens. Cytotoxicity assay showed that the obtained AgNPs were significantly cytotoxic to cancer cell line (MCF-7). In addition, the AgNPs synthesized in this paper can also photo catalytically degrade methylene blue dye under visible light. The potent bioactivity exhibited by the green synthesized silver nanoparticles leads towards the multiple use as antioxidant, antibacterial, anti-biofilm, cytotoxic as well as photo catalytic agent.


Author(s):  
Robert Lotha ◽  
Aravind Sivasubramanian ◽  
Meenakshi Sundaram Muthuraman

Objective: The present study was aimed at the biosynthesis of silver nanoparticles (AgNPs) using aqueous extract of Euphorbia cyathophora leavesand testing their anticancer potential using HT-29 cell line model.Methods: Green synthesis of silver nanoparticles was obtained with the aqueous extract of E. cyathophora. The synthesized nanoparticles wereconfirmed initially by ultraviolet-visible spectroscopy. Further, scanning electron microscopy, transmission electron microscopy, and X-Ray diffractionstudies also ensured the presence of silver nanoparticles. Zeta potential studies revealed the stability of the silver nanoparticles.Results: Antioxidant and anticancer studies of the nanoparticles against HT-29 cell line exhibited remarkable results.Conclusion: This ensures that the synthesized nanoparticles play an important role in medicinal biology.


2017 ◽  
Vol 57 (2) ◽  
pp. 194-200 ◽  
Author(s):  
Abdul A. Buhroo ◽  
Gousul Nisa ◽  
Syed Asrafuzzaman ◽  
Ram Prasad ◽  
Razia Rasheed ◽  
...  

AbstractThe present exploration is focused on the bio-fabrication of silver nanoparticles (Ag NPs) usingTrichodesma indicumaqueous leaf extract as a reducing agent. The synthesized Ag NPs were productively characterized by UV-vis spectroscopy, XRD, and TEM studies. The photosynthesis of Ag NPs was done at room temperature for 24 h and at 60°C. The green synthesis of spherical-shaped Ag NPs bio-fabricated fromT. indicumwith a face centred cubic structure showed average particle sizes of 20–50 nm, which is inconsistent with the particle size calculated by the XRD Scherer equation and TEM analysis. We further explored the larvicidal efficacy of biosynthesized Ag NPs with leaf extracts ofT. indicumagainstMythimna separata. The results showed that Ag NPs (20–50 nm) ofT. indicumpossess good larvicidal activity againstM. separatawith an LC50of 500 ppm. Thus, we can advocate that Ag NPs of 20–50 nm size extracted fromT. indicummay be considered in the pest management programme ofM. separatain future.


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