Phytosynthesis Of Silver Nanoparticles Research Articles

Phyto-synthesis of silver nanoparticles (AgNPs) and its enhanced biological activity examined using methanolic leaf extract of Brassica oleracea Linn

Phyto-synthesis of silver nanoparticles (AgNPs) and its enhanced biological activity examined using methanolic leaf extract of Brassica oleracea Linn

Influence of silver nanoparticles synthesized from Chaenomeles leaf extracts on pathogenic microorganisms Klebsiella pneumoniae, Staphylococcus aureus, and Fusarium culmorum

Herein, we report for the first time the biosynthesis of silver nanoparticles (AgNPs) using leaf extracts of Chaenomeles Lindl. (Rosaceae) plants and its spectral characteristics, as well as antifungal and antibacterial activity. Phytosynthesis of silver nanoparticles on the base of aqueous plant extracts and silver nitrate solution was carried out by an ecofriendly and cost-effective approach. UV-Vis spectroscopy was applied to validate the plant-mediated biosynthesis of AgNPs colloidal solutions by the Surface Plasmon Resonance (SPR) bands in the region of 450–500 nm, characteristic of polycrystalline silver nanoparticles. Scanning microscopy (SEM) revealed a wide variation in range 5–58 nm and a close to spherical shape of plant-derived AgNPs. Raman scattering spectroscopy revealed the suitability of biosynthesized silver nanoparticles as the substrates for surface-enhanced Raman scattering (SERS) spectroscopy with the highest efficiency of AgNPs, biosynthesized from leaf extract of Ch. × superba, which enhanced the Rhodamine 6G dye applied at a concentration of 10–7 M. Assay of antifungal activity performed by well diffusion method revealed the dose-dependent effect of all AgNPs against the phytopathogenic fungus Fusarium culmorum. The most effective AgNPs (Ch. speciosa-AgNPs, Ch. cathayensis-AgNPs, and Ch. japonica-AgNPs) achieved a 1.42–1.63 times greater zone of inhibition of the F. culmorum colonies’ growth compared to the corresponding doses of the known chemical fungicide "Quadris". Micro preparations of the zones of incomplete growth inhibition presented changes in the mycelium morphology of F. culmorum due to the action of nanoparticles, such as deformation (curvature, expansion), and a decrease in the hyphae length and density compared to the control sample. Disc-diffusion assay showed notable species-specific antibacterial activity of AgNPs both against Gram-negative (Klebsiella pneumoniae) and Gram-positive (Staphylococcus aureus) strains. Summarizing, the results indicate the undeniable suitability of aqueous leaf extracts of the genus Chaenomeles species for the successful biosynthesis of silver nanoparticles with many useful properties, whose diverse applications require further research.

PIMENTA DIOICA LEAF EXTRACT USED IN THE SYNTHESIS OF SILVER NANOPARTICLES: CHARACTERIZATION AND EVALUATION OF ANTIMICROBIAL APPLICATIONS

Green synthesis approaches for the synthesis of nanomaterials and their different uses have been researched and garnered the interest of researchers in recent years (1-5). One excellent instrument for the introduction and advancement of nanotechnology is the green synthesis of noble metal nanoparticles. Because no hazardous or toxic chemicals are used during the plant-mediated synthesis process, also known as phytosynthesis, it is sometimes referred to as "green synthesis" (6, 7). In order to control the morphology, size, and stability of synthesised nano-sized structures, metallic nanoparticles can be prepared using a variety of synthesis techniques, including biological, physical, chemical, and others. However, the most intriguing synthesis method is the one for green metallic anoparticle synthesis. Plant extract-based green synthesis techniques have gained a lot of attention because they are both economical and environmentally friendly (8-10) and because a variety of abundant and diverse biomolecules function as reducing and capping agents (11, 12). Modifying the morphology, shape, size, surface to volume ratio, and composition of nanoparticles (NPs) is a crucial step towards achieving improved physical, chemical, and biological properties for desired applications in various fields, including electronics, household appliances, cosmetics, agriculture, and pharmaceuticals (13-17). Green synthesis methods facilitate this process. The safe and environmentally benign character of phytosynthesized silver nanoparticles (Ag NPs) makes them an attractive option for usage in a wide range of applications. Researchers are constantly looking for less dangerous, manageable, effective, large-scale manufacturing, and environmentally friendly synthesis techniques for nanotechnology advancements and their effects on biological things (18-21). Ag NPs are among the metals that have drawn the most attention from researchers because of their unique physiochemical characteristics and exciting potential uses in biomedicine (22-27). In order to lessen microbial contamination, the scientific community is making use of silver nanoparticles (Ag NPs) in nanomedicine and in combination with other biomaterials. Because of these nanoparticles' surface plasmon resonance feature, they have also been investigated for bio-imaging applications (28).

Development of Biologically Active Phytosynthesized Silver Nanoparticles Using Marrubium vulgare L. Extracts: Applications and Cytotoxicity Studies.

Metal nanoparticle phytosynthesis has become, in recent decades, one of the most promising alternatives for the development of nanomaterials using "green chemistry" methods. The present work describes, for the first time in the literature, the phytosynthesis of silver nanoparticles (AgNPs) using extracts obtained by two methods using the aerial parts of Marrubium vulgare L. The extracts (obtained by classical temperature extraction and microwave-assisted extraction) were characterized in terms of total phenolics content and by HPLC analysis, while the phytosynthesis process was confirmed using X-ray diffraction and transmission electron microscopy, the results suggesting that the classical method led to the obtaining of smaller-dimension AgNPs (average diameter under 15 nm by TEM). In terms of biological properties, the study confirmed that AgNPs as well as the M. vulgare crude extracts reduced the viability of human gingival fibroblasts in a concentration- and time-dependent manner, with microwave-assisted extracts having the more pronounced effects. Additionally, the study unveiled that AgNPs transiently increased nitric oxide levels which then decreased over time, thus offering valuable insights into their potential therapeutic use and safety profile.

Phytomediated synthesis of silver nanoparticles using Lepidium Sativum L. and their antifungal and cytotoxic potential

Bio-inspired synthesis of nanoparticles has received immense attention recently due to their vast applications in the biomedical field. Herein, a facile process using aqueous extracts of Lepidium sativum was used for the synthesis of nanosilver. The phytosynthesized silver nanoparticles showed characteristic silver surface plasmon absorption peaks at 420 and 440 nm for nanoparticles synthesized by Lepidium sativum seeds and leaves, respectively. Moreover, the spherical, non-aggregated nanoparticles exhibited a particle size of 150 nm and a zetapotential of -15.2 mv countering 111 nm and a zeta potential of -20 mv for those phytosynthesized by Lepidium sativum seeds and leave aqueous extract correspondingly. Both phytofabricated silver nanoparticles exhibited a potential antifungal effect against Candida albicans with a minimum inhibitory concentration of 1.75 and 2.08 ppm and a promising cytotoxic effect against MCF-7 breast cancer cell line with an IC­50 of 20.1 and 9.3 ppm for nanosilver phytosynthesized by seeds and leaves extracts respectively. The current work provided a simple, environmentally friendly approach for the green synthesis of silver nanoparticles with a potential anticandidal and cytotoxic action against the MCF-7 breast cancer cell line. However, more investigation is required to clarify their safety and precise mode of action.

Phyto-synthesized silver nanoparticles from Sargassum subrepandum: anticancer, antimicrobial, and molluscicidal activities.

In the realm of nanotechnology, the use of algae to produce nanoparticles is an environmentally friendly, sustainable, and economically viable strategy. In the present study, the brown macroalgae Sargassum subrepandum was utilized to effectively produce silver nanoparticles (AgNPs). Through various characterization techniques, the AgNPs' structural integrity was confirmed. AgNPs exhibited significant antimicrobial activity against Pseudomonas aeruginosa and Fusarium equiseti. AgNPs showed cytotoxic effects on the MCF-7 breast adenocarcinoma cell line with an IC50 of 12.5 µg/ml. Treatment with AgNPs resulted in a marked reduction in cell viability, alongside evident apoptotic and necrotic morphological changes in the cancer cells. Through molecular docking studies, a deeper understanding of the interaction between AgNPs and crucial proteins related to cancer has been achieved, AgNPs showed a promising molluscicidal action on Biomphalaria alexandrina snails, a Schistosoma mansoni intermediate host. The half-lethal dose (LC50) of AgNPs was determined to be 0.84 mg/L. The potential consequences of its administration include potential disruptions to the glycolysis profile, as well as potential impacts on the steroidal hormone's estrogen and testosterone and certain kidney function tests. This study highlights the diverse uses of algae-synthesized AgNPs, ranging from healthcare to environmental management, demonstrating their importance in advancing nano-biotechnological solutions.

Phytosynthesis of silver nanoparticles using aqueous sandalwood (Santalum album L.) leaf extract: Divergent effects of SW-AgNPs on proliferating plant and cancer cells.

The biogenic approach for the synthesis of metal nanoparticles provides an efficient eco-friendly alternative to chemical synthesis. This study presents a novel route for the biosynthesis of silver nanoparticles using aqueous sandalwood (SW) leaf extract as a source of reducing and capping agents under mild, room temperature synthesis conditions. The bioreduction of Ag+ to Ago nanoparticles (SW-AgNPs) was accompanied by the appearance of brown color, with surface plasmon resonance peak at 340-360 nm. SEM, TEM and AFM imaging confirm SW-AgNP's spherical shape with size range of 10-32 nm. DLS indicates a hydrodynamic size of 49.53 nm with predominant negative Zeta potential, which can contribute to the stability of the nanoparticles. FTIR analysis indicates involvement of sandalwood leaf derived polyphenols, proteins and lipids in the reduction and capping of SW-AgNPs. XRD determines the face-centered-cubic crystalline structure of SW-AgNPs, which is a key factor affecting biological functions of nanoparticles. This study is novel in using cell culture methodologies to evaluate effects of SW-AgNPs on proliferating cells originating from plants and human cancer. Exposure of groundnut calli cells to SW-AgNPs, resulted in enhanced proliferation leading to over 70% higher calli biomass over control, enhanced defense enzyme activities, and secretion of metabolites implicated in biotic stress resistance (Crotonyl isothiocyanate, Butyrolactone, 2-Hydroxy-gamma-butyrolactone, Maltol) and plant cell proliferation (dl-Threitol). MTT and NRU were performed to determine the cytotoxicity of nanoparticles on human cervical cancer cells. SW-AgNPs specifically inhibited cervical cell lines SiHa (IC50-2.65 ppm) and CaSki (IC50-9.49 ppm), indicating potential use in cancer treatment. The opposing effect of SW-AgNPs on cell proliferation of plant calli (enhanced cell proliferation) and human cancer cell lines (inhibition) are both beneficial and point to potential safe application of SW-AgNPs in plant cell culture, agriculture and in cancer treatment.

Phytosynthesis of silver nanoparticles using guarana (Paullinia cupana Kunth) leaf extract employing different routes: characterization and investigation of in vitro bioactivities

Phytosynthesis of silver nanoparticles using guarana (Paullinia cupana Kunth) leaf extract employing different routes: characterization and investigation of in vitro bioactivities

Voltammetric determination of synthetic food dye brilliant blue FCF

A highly sensitive and selective voltammetric sensor based on a non-woven carbon fiber material modified with phytosynthesized silver nanoparticles and graphene nanoplatelets was developed for determining food synthetic dye Brilliant Blue FCF (E133). Silver nanoparticles were prepared employing simple, fast and environmentally friendly phytosynthesis using sea buckthorn leaf extract without use of harmful chemical reagents. Modification of the carbon fiber electrode with silver phytonanoparticles and graphene nanoplatelets contributed to an increase in the active surface area of the electrode, an increase in the maximum oxidation current of E133 and a decrease in the overvoltage of this process relative to the unmodified electrode. Conditions for producing maximum analytical signal from the dye, including composition of the nanocomposite modifier (mass fraction of silver nanoparticles and graphene nanoplatelets, of 4.4 and 95.6 %, respectively) and the background electrolyte acidity (phosphate buffer solution with pH of 5) were selected. It was found that the process of electrooxidation of E133 dye on the modified carbon fiber electrode is irreversible, two-electron, occurs in the absence of protons and is controlled by diffusion. Scheme of the electrode process consistent with the literature data is suggested. The sensor is characterized by a low detection limit (6.1 nM), a wide range of detectable concentrations (0.06–40 μM), and good repeatability of the analytical signal of the dye sr<7 %. It was shown that potential interferents did not have a significant effect on the analytical signal of E133 dye. The developed sensor was successfully applied for analysis of beverages and caramel without preliminary sample preparation. The values of recovery of E133 dye in the range of 97–103 % in real samples prove the absence of a systematic error.

Modulation of terpenoid indole alkaloid pathway via elicitation with phytosynthesized silver nanoparticles for the enhancement of ajmalicine, a pharmaceutically important alkaloid.

The use of silver nanoparticles as elicitors in cell cultures of Rauwolfia serpentina resulted in increased levels of ajmalicine, upregulated structural and regulatory genes, elevated MDA content, and reduced activity of antioxidant enzymes. These findings hold potential for developing a cost-effective method for commercial ajmalicine production. Plants possess an intrinsic ability to detect various stress signals, prompting the activation of defense mechanisms through the reprogramming of metabolites to counter adverse conditions. The current study aims to propose an optimized bioprocess for enhancing the content of ajmalicine in Rauwolfia serpentina callus through elicitation with phytosynthesized silver nanoparticles. Initially, callus lines exhibiting elevated ajmalicine content were established. Following this, a protocol for the phytosynthesis of silver nanoparticles using seed extract from Rauwolfia serpentina was successfully standardized. The physicochemical attributes of the silver nanoparticles were identified, including their spherical shape, size ranging from 6.7 to 28.8nm in diameter, and the presence of reducing-capping groups such as amino, carbonyl, and amide. Further, the findings indicated that the presence of 2.5mg L-1 phytosynthesized silver nanoparticles in the culture medium increased the ajmalicine content. Concurrently, structural genes (TDC, SLS, STR, SGD, G10H) and regulatory gene (ORCA3) associated with the ajmalicine biosynthetic pathway were observed to be upregulated. A notable increase in MDA content and a decrease in the activities of antioxidant enzymes were observed. A notable increase in MDA content and a decrease in the activities of antioxidant enzymes were also observed. Our results strongly recommend the augmentation of ajmalicine content in the callus culture of R. serpentina through supplementation with silver nanoparticles, a potential avenue for developing a cost-effective process for the commercial production of ajmalicine.

Phyto-Synthesis and Characterization of Silver Nanoparticles Using Box-Behnken Design and Its Anti-Alternaria Activity

Alternaria alternata is a global fungal pathogen that causes symptoms such as leaf blight and seed rot resulting in economically significant yield losses in different varieties of crops. Green synthesis of nanoparticles is preferred over other methods of synthesis due to their safety, eco-friendly approach, and cost-effectiveness. Phyto-synthesis of silver nanoparticles (Ag-NPs) using seed extract of Abrus precatorious was optimized and characterized using the Box-Behnken design (BBD). Ag-NPs with a UVmax of 409.01 nm and a crystallite and particle size of 23.75 and 34.36 nm, respectively, were synthesized. In vitro anti-alternaria activity of Ag-NPs showed a concentration-dependent inhibition of the mycelia with a maximum inhibition of 54.61% at 200 ppm which was significantly different (p < 0.05) from propiconazole (1 ppm) with 100% inhibition. A scanning electron micrograph (SEM) of mycelia treated with 200 ppm of Ag-NPs showed a shrunken and shriveled mycelia while the ultrastructure of the mycelia under a transmission electron microscope (TEM) showed the alteration of the fungus cell wall and disappearance of cellular organelles compared to the control sample, while energy dispersive x-ray spectroscopy (EDX) analysis of the mycelia showed the localization of elemental Ag (0.95%) within the cell of the fungus compared to the control. The results of this study highlighted the antifungal potential of Ag-NPs against fungicide-resistant Alternaria alternata to reduce the environmental impact of synthetic fungicides.

Phytosynthesis of silver nanoparticles by Paulownia fortunei fruit exudates and its application against Fusarium sp. causing dry rot postharvest diseases of banana

Over the recent years, banana cultivation has increased in the South-Eastern provinces of Iran. Management of Fusarium diseases in banana poses considerable yield loss as the application of chemical and biological treatments remains challenging. At the present research, about 10 Fusarium isolates causing dry rot on banana fruits were isolated and based on the pathogenicity test, isolate MSN-7 was considered as the most pathogenic isolate. Isolate MSN-7 was identified by using the ITS (ITS1 and ITS4) genomic region. BLAST results showed that it had the highest similarity (99%) with Fusarium chalmydosporum (MN533778.1). The objective of our research was to examine different concentrations of Silver nanoparticles (SNPs) biosynthesized by Paulownia fortunei L.) Fruit Exudates as a novel antifungal agent for reduce of pathogencity of Fusarium dry rot of banana. The synthesis of SNPs was conducted utilizing Paulownia fruit extracts as an environmentally friendly biosource. The exudates derived from Paulownia fruit demonstrated the capability to generate nanoparticles with an average size of 46 nm. Analysis conducted using a transmission electron microscope (TEM) revealed that these nanoparticles possess a polyhedral structure. Furthermore, when applied at concentrations of 10, 20, 40, and 80 μg/ml, these biosynthetic nanoparticles exhibited the ability to inhibit the growth of Fusarium fungus mycelia, as well as induced the destruction of the fungal hyphae.

Phyto-synthesis of silver nanoparticles from Plumeria pudica leaf extract and its application in anti-cancerous activity

In this study, we have developed an environment friendly and novel approach for the synthesis of silver nanoparticles utilising plumeria pudica leaf extract. In this technique, the leaf extract was employed as both a reducing agent for the reduction of a silver nitrate (AgNO3) solution and a capping agent, leading to the synthesis of silver nanoparticles (Ag NPs). The outcomes of these analyses revealed an average particle size of ∼19 nm as determined by SEM, while XRD measurements indicated a crystalline domain size of ∼12 nm and a lattice parameter of approximately 4.087467 Å. Furthermore, the anti-cancer potential of the synthesised silver nanoparticles was evaluated, unveiling an IC50 value of around 28 µM. This suggests that the introduced silver nanoparticles may have triggered apoptosis, consequently inducing cell death. These findings underscore the potential of utilising environmentally benign silver nanoparticles in lung cancer chemotherapy.

Phytosynthesis of Silver Nanoparticles Using Oscimum sanctum Leaf Extract and Studies on Its Antidiabetic, Antioxidant, and Antibacterial Properties.

The green synthesis of plasmonic metal nanoparticles (NPs) has gained considerable attention among researchers as it is cost-effective, environmentally friendly, energy-saving, and nontoxic. We have synthesized silver NPs (Ag NPs) with Oscimum sanctum (holy Tulsi) medicinal plant leaf extract by green synthesis methods. Further, we investigate the antibacterial, antioxidant, and antidiabetic activities of the synthesized Ag NPs. Oscimum sanctum leaf extract has secondary metabolites such as phenolic and flavonoid compounds, which play a significant role in the synthesis of Ag NPs. Subsequently, these bioactive molecules get adsorbed on the large surfaces of the synthesized NPs. Spectroscopic techniques such as X-ray diffraction (XRD), UV-visible absorption, Fourier-transform infrared, and scanning electron microscopy have been used to study and characterize the phytosynthesized Ag NPs. The XRD pattern confirms the formation of crystalline Ag NPs with a high degree of intensity. UV-visible absorption spectra confirm the surface plasmon resonance peak in the range of 440-450 nm. A scanning electron microscopy picture reveals homogeneous growth of Ag NPs with particle sizes of 200-400 nm; however, crystallite size along different planes has been estimated in the range of 18-23 nm. We have found that these Ag NPs synthesized with Oscimum sanctum leaf extract show inhibitory activity against α-amylase and α-glucosidase enzymes in vitro. Our findings further reveal that these Ag NPs are more effective in inhibiting the growth of Salmonella typhi bacteria as compared to other bacterial strains.

Phyto-synthesized silver nanoparticles from ubiquitous weeds Sida acuta and Artemisia absinthium for controlling japanese encephalitis vector

Phyto-synthesized silver nanoparticles from ubiquitous weeds Sida acuta and Artemisia absinthium for controlling japanese encephalitis vector

Phyto Fabrication of Silver Nanocomposites from Ageratum conyzoides as Potent Mosquitocidal and Antidengue Activity of Aedes aegypti

Mosquitoes pose an enormous threat to millions of people worldwide and transmit important diseases, including malaria, dengue, yellow fever, filariasis, Japanese encephalitis and the Zika virus. Currently, a growing number of phyto-synthesized silver nanoparticles (AgNPs) have recently been proposed as effective mosquito larvicides and are gaining traction over synthetic chemical pesticides due to their less deleterious effects on non-target species and novelty in mechanisms. action. The current study was conducted to evaluate the larvicidal and pupicidal activity of AgNP synthesized from Ageratum conyzoides against dengue vector Aedes aegypti as well as in vitro antiviral assay. The biosynthesized AgNPs were characterized using a UV-Vis spectrometer, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The mosquito larvae were tested with biosynthesized AgNPs and the LC50 values recorded were I-stage (20.451), II-stage (23.307), III-stage (27.397), IV-stage (33.351), and pupa (39.668), respectively. To screen the anti-dengue properties of A. conyzoides-synthesized AgNP, an in vitro antiviral assay was performed. The present research reported moderate cytotoxicity rates in Vero cells exposed to A. conyzoides-synthesized AgNP at various concentrations. From this we observed that no adverse morphological differences were found in the treated cells that were comparable to the control Vero cells. Overall, our results demonstrated that AgNPs synthesized by A. conyzoides can be used to design newer and safer dengue control agents.

Phytosynthesis of Silver Nanoparticles Using Leonurus cardiaca L. Extracts.

The present work describes, for the first time in the literature, the phytosynthesis of silver nanoparticles using Leonurus cardiaca L. extracts. The influence of the extraction method (classical temperature extraction and microwave extraction), as well as of the extract concentration on the characteristics of the nanoparticles, was studied using analytical methods, such as UV-Vis spectrometry, X-ray diffraction, dynamic light scattering, and transmission electron microscopy. Experimental data suggest that use of lower extract concentration leads to smaller dimensions nanoparticles, the same effect using the extract obtained by microwave-assisted extraction. The smallest recorded crystallite sizes (by X-ray diffraction) were under 3 nm. The antioxidant properties (determined by the DPPH assay) and the antimicrobial potential (determined against Gram-negative and Gram-positive strains) are enhanced by the phytosynthesis process (as demonstrated by the comparison of the nanoparticles' properties with the parent extracts). The present work could also represent an important step in obtaining nanoparticles with enhanced properties and controlled morphologies, but also offers information on the phytosynthesis of metallic nanoparticles using low extract concentrations.

DEVELOPMENT OF TECHNOLOGY OF PRODUCTION AND QUALITY ASSESSMENT OF DRUG SUBSTANCE " DRY EXTRACT OF SCUTELLARIA ISCANDERI L. WITH SILVER NANOPARTICLES"

This study demonstrates the results of experimental studies aimed at the development of technology and assessment of quality of drug substance containing a dry extract of a flavonoid-containing herb and silver nanoparticles, as well as the optimal technological parameters of the phytosynthesis process and methods for the qualitative and quantitative content of biologically active substances have been developed. Phytosynthesis of silver nanoparticles was carried out using plant extracts, in which biologically active substances, flavonoids, act as an agent that reduces silver ions to nanoparticles. The optimal technology for the production of silver nanoparticles was chosen and the sample obtained at t =50 °C and the ratio of extract: silver nitrate = 1:4 was chosen as the optimal one. Additionally, the expiration date of the drug was determined for the development of regulatory documentation. During quality assessment, it was found that the quantitative content of silver nanoparticles should be at least 2 mg/g. As a result, it became possible to produce a substance used in the preparation of local antibacterial and antifungal drugs for the treatment of skin diseases.

Effects of Different Parts of the Okra Plant (Abelmoschus esculentus) on the Phytosynthesis of Silver Nanoparticles: Evaluation of Synthesis Conditions, Nonlinear Optical and Antibacterial Properties

In this work, stable and spherical silver nanoparticles (AgNPs) were synthesized in situ from silver salt (silver nitrate) using the aqueous extract of the okra plant (Abelmoschus esculentus) at room temperature and ambient pH conditions. The influences of different parts of the plant (such as the leaves, stems, and pods) on the chemical-reducing effectiveness of silver nitrate to silver nanoparticles were investigated. The aqueous extract of the leaves was found to be more effective in the chemical reduction of silver nanoparticles and in stabilizing them at the same time. The silver nanoparticles produced were stable and did not precipitate even after storage for 1 month. The extract of the stem was less effective in the reduction capacity followed by the extract of the pods. The results indicate that the different amounts of phytochemicals present in the leaves, stems, and pods of the okra plant are responsible for the chemical reduction and stabilizing effect. The silver nanoparticles were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The surface plasmon resonance (SPR) peak at 460 nm confirmed the formation of silver nanoparticles. The nanoparticles were spherical with an average size of 16 nm and polycrystalline with face-centered cubic (fcc) structures. The z-scan technique was used to study the nonlinear refraction and absorption coefficients of AgNPs at wavelengths of 488 and 514 nm under C.W. mode excitation. The nonlinear refraction index and nonlinear absorption coefficients were calculated in the theoretical equations in the experimental data. The antibacterial properties of the nanoparticles were evaluated against Gram-positive and Gram-negative bacteria.

Phytosynthesis of silver nanoparticles using Mangifera indica leaves extract at room temperature: Formation mechanism, catalytic reduction, colorimetric sensing, and antimicrobial activity

In this study, silver nanoparticles (AgNPs) were synthesized using the leaves extract of mango (Mangifera indica) as a green reducing agent and stabilizer. The effects of time, the AgNO3 solution volume, and pH on the formation of AgNPs were investigated via UV–vis spectroscopy and dynamic light scattering. The results revealed that the greatest AgNPs stability was obtained with the AgNO3 volume of 300 µL, the reaction time of 30 min, and pH 10. The catalysis of organic dye reduction, colorimetric sensing, and antimicrobial activities of the fabricated AgNPs were also evaluated. Particularly, the catalysis reduction experiments confirmed a good catalysis performance of the AgNPs for decolorization of the crystal violet (CV) with a removal efficiency of 98.83 % under ultrasonic-assisted conditions, which was higher than that obtained under stirring conditions. Additionally, the fabricated AgNPs possessed good sensing performance of H2O2 and Hg(II) with a detection limit of 20.21 and 25.87 μg/L, respectively. The material also showed good antimicrobial activity, which efficaciously inhibited the growth of Gram-positive, Gram-negative bacteria, and fungus with inhibition of over 85 %. According to the aforementioned results, the AgNPs synthesized from the Mangifera indica leaves extract can be promisingly utilized in medical and environmental treatment.