scholarly journals Optimization of Selected Process Parameters Affecting Yield of Green Synthesized Silver Nanoparticles and Their Antibacterial Activity

Author(s):  
F. A. Ekaji ◽  
C. O. Akujobi ◽  
S. I. Umeh

Aims: To optimize effects of selected process parameters affecting yield of green synthesized silver nanoparticles and their antibacterial activity. Study Design: Study was designed with 3 factors Box Behnken Design (Minitab 17) and Response optimizer (Minitab 17) was used to determine optimum values of the factors. Place and Duration of Study: Department of Microbiology, Federal University of Technology, Owerri, Nigeria, from March to November, 2020. Methodology: After extraction by boiling, qualitative phytochemical analysis of leaves’ extracts of Ipeoma batatas, Commelina africana and Manihot esculenta was carried out. Following synthesis of silver nanoparticles as prescribed by Box Behnken design, yield of AgNPs was optimized with Response optimizer (Minitab 17). Then antibacterial activity of resulting AgNPs was tested against isolates of P. aeruginosa and E. coli. Results: Extracts contained alkaloids, tannins, proteins and amino acids, flavonoids and phenolic compounds, but no sterols and cardiac glycosides. Optimum pH, temperature and time obtained with Response Optimizer resulted in 62.6%, 55.8% and 54.9% increase in yield of AgNPs, with leaf extracts of C. africana, M. esculenta and I. batatas respectively, compared to un-optimized conditions. Absorbance for resulting AgNPs peaked between 380 to 400 nm. Zones of inhibition (mm) of P. aeruginosa with AgNPs synthesized using extracts of C. africana, I. batatas and M. esculenta were 10, 10 and 9 respectively, under un-optimized condition, and 12, 10 and 8 respectively, for optimized conditions. Against E. coli, they were 11, 11 and 12 for AgNPs synthesized with extracts of C. africana, I. batatas and M. esculenta respectively, under un-optimized condition, and 13, 9 and 11 respectively, for optimized conditions. Conclusion: Leaf extracts of C. africana, I. batatas and M. esculenta can be used in synthesizing AgNPs, with marked antibacterial activities. Box Behnken design is useful for optimization of effects of process parameters.

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3790
Author(s):  
Pratama Jujur Wibawa ◽  
Muhammad Nur ◽  
Mukhammad Asy’ari ◽  
Wijanarka Wijanarka ◽  
Heru Susanto ◽  
...  

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).


2020 ◽  
Vol 26 (6) ◽  
pp. 200454-0
Author(s):  
Sabaoon Shamshad ◽  
Jamshaid Rashid ◽  
Ihsan-ul-haq ◽  
Naseem Iqbal ◽  
Saif Ullah Awan

Multidrug resistance of bacteria is an emerging human health hazard and warrants development of novel antibacterial agents with more effective mode of action. Here, zinc oxide and silver nanomaterials were prepared using Ficus palmata Forssk leaf extract with efficient antibacterial activity. SEM coupled with EDS confirmed the spherical symmetry with average particle diameter 50 to 65 nm while the XRD confirmed crystalline face centered cubic structure of silver and hexagonal crystallize phase of zinc oxide nanoparticles. Antibacterial activity was evaluated for 8 pathogenic bacterial strains including 3 drug resistant pathogenic strains. The nanoparticles showed enhanced growth inhibition for resistant strains in comparison with the broad-spectrum antibiotics i.e. roxithromycin and cefixime. Minimum inhibitory concentration in μg.mL<sup>-1</sup> of silver nanoparticles was found to be as low as 33.3 for resistant Streptococcus haemolyticus; 11.1 for Staphylococcus aureus and E Coli; and 3.7 μg.mL<sup>-1</sup> for resistant Pseudomonas aeruginosa. Similarly, the minimum inhibitory concentration of zinc oxide nanoparticles was found to be 100 μg.mL<sup>-1</sup> against resistant Streptococcus haemolyticus and Staphylococcus aureus; 11.1 μg.mL<sup>-1</sup> for resistant Pseudomonas aeruginosa; and 3.7 μg.mL<sup>-1</sup> against resistant E coli. Ficus palmata Forssk leaf extracts can be explored effectively for synthesizing active antibacterial nanomaterials as a non-toxic and environmentally benign synthesis route.


2021 ◽  
Vol 5 (1) ◽  
pp. 436-444
Author(s):  
Sabiu Shitu ◽  
M. Attahiru ◽  
F. A. Iliya

The antibacterial activity of Tokar sha; a local traditional medication widely used by many people in North-west zone of Nigeria especially Sokoto, Kebbi and Zamfara against enteric infections were examined against some clinical isolates of pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Bacillus cereus and Salmonella typhi) using agar well diffusion method. The pattern of inhibition varied with the tokar sha concentrations and the organisms tested. The tokar sha was more effective on E. coli with a maximum zone of growth inhibition of 25mm at 35mg/ml followed by B. cereus (20mm). However, S. aureus and S. typhi were resistant to tokar sha at all concentrations tested. The minimum inhibitory concentrations (MIC) were found to be 35mg/ml for both E. coli and B. cereus. The antibacterial activities exhibited by tokar sha in this study could be attributed to the presence of its constituents which signifies the potential of the tokar sha as a therapeutic agent. These findings may justify the ethnomedicinal use of tokar sha as an antibacterial agent against enterobacteria


2021 ◽  
Author(s):  
Bondy Lourenço ◽  
Asimbawe Kiza ◽  
Abrão Amândio João ◽  
Clemência Félix Odala Niconte ◽  
Pompílio Armando Vintuar ◽  
...  

Abstract Background: Currently, several studies are being conducted to test antibacterial activity of various medicinal plants, in attempt to develop new antibiotics or to potentiate the action of antibiotics of known clinical use. In this research, phytochemical analysis and in vitro antibacterial activity of leaf extracts of Lantana camara L were performed.Methods The extracts were obtained through maceration with 90% ethanol. In phytochemical analysis, alkaloids, flavonoids, tannins and saponins were identified using specific reagents for each class.The antibacterial activity was analyzed using the disk diffusion method according to Kirby-Bauer, against Escherichia coli and Staphylococus aureus.Key findings The diameters of the inhibition halos varied between 0.7 and 12 mm, with an average of 8.26 mm for strains of S. aureus and there was no inhibition for E. coli. The results showed a significant difference between the inhibition halos and the tested concentrations for S. aureus. In conclusion L. camara leaf extracts are rich in bioactive compounds and have a good antibacterial potential against S. aureus and not for E. coli. And there was no relationship between the concentration of the extract and the diameter of the halo of inhibition of the evaluated microorganism.


Author(s):  
Khalil Ahmad ◽  
Raeesa Noor ◽  
Muhammad Younus ◽  
Akram Chohan ◽  
Ume Habiba ◽  
...  

Background: Appearance of antibiotic resistance has raised the demand to find alternative therapies and modified drug delivery system of medicinal plants to treat bacterial infections. Objective: The aim of this study is the green synthesis and characterization of silver nanoparticles by using crude extract of Crotalaria burhia and to evaluate their antibacterial potential. Methods: The roots and stems of plant were used to prepare the crude extract. The phytochemical analysis of different compounds in extract was performed. 1mM AgNO3 and different concentrations of plant extract were used for the green synthesis of silver nanoparticles. The particles size and zeta potential were measured by zeta sizer while surface morphology of silver nanoparticles was observed with Scanning Electron Microscope (SEM). The antibacterial activity of silver nanoparticles was performed by 96 well microdilution plate method. Results: The particle size and zeta potential of optimized formulation was 92 nm and -24.8 mV. The SEM analysis showed that silver nanoparticles are irregular and spherical shape. The antibacterial activity showed that MIC value of silver nanoparticles was lower for E. coli than S. aureus. Conclusion: Silver nanoparticles possess potent bactericidal activity against E. coli and moderate activity against S. aureus. It had been concluded that these nanoparticles can be used against multi-drug resistant bacterial infections.


2021 ◽  
Vol 22 (1) ◽  
pp. 28-34
Author(s):  
Saddam Hussain Bughio

The objective of this study was to investigate the impact of phytochemical analysis and the antibacterial activity of extracts of stem, flowers and leaves of Tamarix dioica Roxb. ex Roth. Four solvents namely, diethyl ether, ethyl acetate, methanol and acetone were selected to obtain extracts from different parts of the plant. The organic solvent extracts were investigated for phytochemical analysis and antibacterial activity against two bacterial strains, namely Escherichia coli and Staphylococcus aureus. The result of phytochemicals revealed the presence of various constituents, such as phlobatannins, tannins, saponins, alkaloids, phenols, proteins, terpenoids, flavonoids and steroids by using standard procedures. Most of these components were present in methanol and ethyl acetate extract. Therefore, four out of two extracts, such as methanol and ethyl acetate extracts from stems, flowers, and leaves, were used to test their evidence of antibacterial activity. From this, it was observed that the methanol extracts of stem, flowers and leaves of T. dioica were highly effective together with E. coli and S. aureus with a minimum inhibitory concentration (MIC) value of 500 μg/mL. Considering that the ethyl acetate (EA) extracts from the stem, flowers and leaves of T. dioica were examined to be ineffective against E. coli and S. aureus and MIC values were not observed in two strains of bacteria.


2021 ◽  
Author(s):  
Bondy Jorge Lourenço ◽  
Asimbawe Kiza ◽  
ABRÃO AMÂNDIO JOÃO ◽  
Clemência FÉLIX ODALA Niconte ◽  
POMPÍLIO ARMANDO Vintuar ◽  
...  

Abstract Background: Currently, several studies are being conducted to test antibacterial activity of various medicinal plants, in attempt to develop new antibiotics or to potentiate the action of antibiotics of known clinical use. In this research, phytochemical analysis and in vitro antibacterial activity of leaf extracts of Lantana camara L were performed.The extracts were obtained through maceration with 90% ethanol. In phytochemical analysis, alkaloids, flavonoids, tannins and saponins were identified using specific reagents for each class.The antibacterial activity was analyzed using the disk diffusion method according to Kirby-Bauer, against Escherichia coli and Staphylococus aureus. Results: The diameters of the inhibition halos varied between 0.7 and 12 mm, with an average of 8.26 mm for strains of S. aureus and there was no inhibition for E. coli. The results showed a significant difference between the inhibition halos and the tested concentrations for S. aureus. Conclusions: L. camara leaf extracts are rich in bioactive compounds and have a good antibacterial potential against S. aureus and not for E. coli. And there was no relationship between the concentration of the extract and the diameter of the halo of inhibition of the evaluated microorganism.


2016 ◽  
Vol 8 (4) ◽  
pp. 2189-2195
Author(s):  
Manasa Govindaraju ◽  
Mahendra Chikkamadaiah ◽  
Murali Mahadevamurthy ◽  
Mahesh Holenarsipura Mylari ◽  
Sudarshana Mysore Shankar Singh

The present study focuses on the use of salicylic acid as a plant growth hormone for the induction of callus in Sauropus androgynus and Artemisia annua plants. Higher induction of callus of 72% in S. androgynus (NAA+BAP+SA at +2.5+2.5 mg/ l concentration) and 64% in A. annua (NAA+Kn+SA at 1.0+2.5+2.5 mg/ l concentration) were observed when compared to 52% and 51%, respectively in individual supplementation of plant growth regulators. The phytochemical analysis also revealed the presence of maximum phytochemicals in callus extract compared to leaf extracts of S. androgynus and A. annua there by corroborating with the results of callus induction. The methanol extracts of both callus and leaf extracts of S. androgynus and A. annua exhibited antibacterial activity against all the test pathogens viz., S. aureus, B. subtilis, S. typhi and E. coli. A maximum inhibition zone of 20 mm was observed against S. typhi in methanol callus extract of S. androgynus followed by 18 mm inhibition zone against S. aureus with same extract. It was evident from the results both callus and leaf extracts of the selected plants possessed potential antibacterial activity against all the test pathogens with one or the other solvent extracts. The findings provide a new facelift for callus induction using salicylic acid in selected plants and also pave way for identification of novel compounds for drug development from S. androgynus and A. annua.


2020 ◽  
Vol 7 (1) ◽  
pp. 12
Author(s):  
Gabriele Meroni ◽  
Joel F. Soares Filipe ◽  
Piera A. Martino

Silver nanoparticles (AgNPs) are promising alternatives to antibiotics. The aims of this study were to produce AgNPs using two biological methods and determine their antibacterial activity against Pseudomonas aeruginosa and Staphylococcus pseudintermedius. AgNPs were biosynthesized from an infusion of Curcuma longa (turmeric) and the culture supernatant of E. coli. Characterization was achieved by ultraviolet-visible spectroscopy and by Transmission Electron Microscopy (TEM). The antibacterial properties of NPs from C. longa (ClAgNPs) and E. coli (EcAgNPs), alone and in combination with carbenicillin and ampicillin, were investigated through the Kirby-Bauer disk diffusion assay and the minimum inhibitory concentration (MIC). Dimensions of NPs ranged from 11.107 ± 2.705 nm (ClAgNPs) to 27.282 ± 2.68 nm (EcAgNPs). Kirby-Bauer and MIC assays showed great antibacterial abilities for both NPs alone and in combination with antibiotics. EcAgNPs alone showed the most powerful antibacterial activities, resulting in MIC values ranging from 0.438 ± 0.18 µM (P. aeruginosa) to 3.75 ± 3.65 µM (S. pseudintermedius) compared to those of ClAgNPs: 71.8 ± 0 µM (P. aeruginosa) and 143.7 ± 0 µM (S. pseudintermedius). The antibiofilm abilities were strain-dependent, but no statistical differences were found between the two NPs. These results suggest the antibacterial potential of AgNPs for the treatment of infectious diseases.


Author(s):  
S. Zengeni ◽  
J. Chifamba ◽  
I. Mutingwende ◽  
T. Manyarara

Bacterial skin infections are common in the tropics and the emergence of resistant bacterial strains has complicated treatment outcomes especially in immune compromised patients. This study focused on determining the antibacterial activity and preliminary phytochemical screening of the plant, Burkea Africana, which has been used for decades to treat various ailments in Southern Africa. Phyto-constituent determination and antibacterial assay was carried out on the hydro-ethanolic and aqueous leaf extracts of Burkea Africana. The Agar well diffusion method was used to investigate the antibacterial efficacy of both extracts. Activity was measured against P. aeruginosa, E. coli, S. aureus and E. faecalis using ciprofloxacin as the standard. For both extracts, phytochemical analysis revealed the presence of steroids, tannins, saponins and carbohydrates. The 70% hydro-ethanolic extract however revealed more phyto-constituents including flavonoids and alkaloids. For both extracts antibacterial activity was comparable to the standard. The highest zone of inhibition recorded for the water extract was 22±0.4 mm at 500 mg/ml for E. coli while the standard, Ciprofloxacin had a zone of inhibition of 25±0.33 mm. The ethanolic extract showed higher antibacterial efficacy when compared to ciprofloxacin against S. aureus. The zone of inhibition for the 70% ethanolic extract was 25.4±0.50 mm and that of the standard was 27±0.48 mm. Antibacterial activity was generally higher in the ethanolic extract than the water extract. It is therefore concluded that B. africana exhibits antibacterial activity.


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