Green Synthesis of Silver Nanoparticles from Leaf Extract of Nyctanthes arbor-tristis L. and Assessment of Its Antioxidant, Antimicrobial Response

Evaluation of antibacterial activity, in-vitro cytotoxicity and catalytic activity of biologically synthesized silver nanoparticles using leaf extracts of Leea macrophylla

Nanotechnology has become a cutting-edge field of research that has emerged as an interdisciplinary research area and contributes to almost every field of science. With the increasing demand for sustainable greener products, attention has recently been focused on green nanotechnology. This study manifested the aptitude of Leea macrophylla (LM) leaf extract, fortified with phytochemicals, to biosynthesize silver nanoparticles (AgNPs) for the first time. As soon as the AgNPs were biosynthesized, they immediately changed color, and the distinctive surface plasmon resonance (SPR) occurred at 420 nm in the Ultraviolet-Visible spectrum, proving that the biosynthesis had been successful. Fourier Transform Infrared Spectroscopy (FTIR) was used to examine the phytochemicals present in the LM leaf extract, those are accountable for the formation and stabilization of AgNPs. The Transmission Electron Microscope (TEM) revealed the formation of quasi spherical silver nanoparticles with an average diameter of 22.77 nm. Synthesized nanoparticles were further characterized by X-ray diffraction (XRD), Field Emission Scanning Electron microscope (FESEM), Energy Dispersive X-ray (EDX), Dynamic Light Scattering (DLS) and Thermogravimetric analysis (TGA). The production of AgNPs with high metal content from LM leaf extract exhibited encouraging results. The LM leaf extract mediated silver nanoparticles evinced significant antibacterial and catalytic activities. The cytotoxicity effects of biosynthesized AgNPs were tested on brine shrimps.

Silver nanoparticles green synthesized with leaf extract of disease-resistant amaranthus genotypes effectively suppress leaf blight (Rhizoctonia solani Kühn) disease in a susceptible red amaranthus cultivar

Silver nanoparticles (AgNPs) were green synthesized using leaf extract of the leaf blight disease (Rhizoctonia solani) susceptible red amaranthus (Amaranthus tricolor L.) and the disease-resistant green (A. dubius) and the wild amaranthus (A. viridis) genotypes, physically characterized, and assessed for their anti-fungal effects against R. solani. The green synthesized nanostructures showed an absorption maximum typical of silver nanoparticles in spectroscopy, and face-centered cubic structures in X-ray diffraction. Field Emission Scanning Electron Microscopic analysis and High-Resolution Transmission Electron Microscopy revealed the size range to be 35-45 nm for all the samples. In vitro mycelial growth inhibition of the pathogen occurred with 500 and 750 ppm concentrations of the nanoparticles in a poisoned-food assay. Further, detached leaves of red amaranthus variety were sprayed with the nanoparticles, and then challenged with the pathogen. There was significant difference in lesion development on leaves sprayed with Ad-AgNPs and Av-AgNPs compared to those treated with At-AgNPs. In the in vivo assay, challenging with the pathogen after spraying the foliage of the leaf blight susceptible red amaranthus variety with Ad-AgNPs at 750 ppm concentration recorded the lowest disease index (7.40) followed by that received Av-AgNPs spray at the same concentration (17.69), five days after inoculation. At-AgNPs treated plants had a disease index of 49.38. Our findings suggest that application of AgNPs green synthesized with leaf extract of disease-resistant genotypes of amaranthus effectively suppressed leaf blight disease incidence in a susceptible amaranthus genotype. To our knowledge, this is the first report on the improved plant pathogen-suppressive activity of any metal nanoparticle when biogenically synthesized using extracts from a disease-resistant plant genotype.

Use of Euphorbia balsamifera Extract in Precursor Fabrication of Silver Nanoparticles for Efficient Removal of Bromocresol Green and Bromophenol Blue Toxic Dyes

Silver nanoparticles (Ag-NPs) are attracting great attention for their use in various applications, along with methods for their green and facile production. In this study, we present a new eco-friendly approach based on the use of Euphorbia balsamifera extract (EBE) in the green synthesis of silver nanoparticles (Ag-NPs), which are then applied as a reducing and stabilizing agent for the efficient removal of water-based reactive dyes such as bromocresol green (BCG) and bromophenol blue (BPB). The as-prepared Ag-NPs are quasi-spherical in shape, with an average diameter of 20-34 nm. Diverse characterization methods, including X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis, were used to analyze these Ag-NPs. The results reveal that water-soluble biomolecules in the Euphorbia balsamifera extract play an important role in the formation of the Ag-NPs. The removal of toxic dyes was studied under varied operational parameters such as Ag-NP dosage, initial dye concentration, pH, stirring time, and temperature. Under the optimum investigated conditions, nearly 99.12% and 97.25% of the bromocresol green and bromophenol blue dyes, respectively, were removed. Both BCG and BPB adsorption were found to adhere to pseudo-second-order kinetics (r₂² = 1 and 0.995) and fit the Langmuir isotherm models well (R₁² = 0.998 and 0.994), with maximal monolayer adsorption capacities of 20.40 and 41.03 mg/g, respectively. Their adsorption processes were observed to be intrinsically endothermic. The results confirm the potential of the Euphorbia balsamifera extract as a low-cost, nontoxic, and eco-friendly natural resource for the synthesis of Ag-NPs that may be useful in the remediation of hazardous dye-contaminated water sources.

Nematocidal and Bactericidal Activities of Green Synthesized Silver Nanoparticles Mediated by Ficus sycomorus Leaf Extract

Nanoparticles effectively control most plant pathogens, although research has focused more on their antimicrobial than their nematocidal properties. This study synthesized silver nanoparticles (Ag-NPs) through a green biosynthesis method using an aqueous extract of Ficus sycomorus leaves (FS-Ag-NPs). The nanoparticles were characterized using SEM, TEM, EDX, zeta sizer, and FTIR. The TEM results showed that the synthesized NPs were nanoscale and had an average particle size of 33 ± 1 nm. The elemental silver signal at 3 keV confirmed the formation of Ag-NPs from an aqueous leaf extract of F. sycomorus. The FTIR analysis revealed the existence of several functional groups in the prepared Ag-NPs. The strong-broad band detected at 3430 cm^-1 indicated the stretching vibration of -OH (hydroxyl) and -NH₂ (amine) groups. The nematocidal activity of biosynthesized FS-Ag-NPs has been evaluated in vitro against the root-knot nematode Meloidogyne incognita at 24, 48, and 72 h. The FS-Ag-NPs at a 200 µg/mL concentration applied for 48 h showed the highest effectiveness, with 57.62% nematode mortality. Moreover, the biosynthesized FS-Ag-NPs were also tested for their antibacterial activity against Pectobacterium carotovorum, P. atrosepticum, and Ralstonia solanacearum. With the application of nanoparticles, the reduction in bacterial growth gradually increased. The most potent activity at all concentrations was found in R. solanacearum, with values of 14.00 ± 2.16, 17.33 ± 2.05, 19.00 ± 1.41, 24.00 ± 1.41, and 26.00 ± 2.83 at concentrations of 5, 10, 15, 20, and 25 µg/mL, respectively, when compared with the positive control (Amoxicillin 25 µg) with a value of 16.33 ± 0.94. At the same time, the nanoparticles showed the lowest reduction values against P. atrosepticum when compared to the control. This study is the first report on the nematocidal activity of Ag-NPs using F. sycomorus aqueous extract, which could be a recommended treatment for managing plant-parasitic nematodes due to its simplicity, stability, cost-effectiveness, and environmentally safe nature.

Phytochemicals, Antioxidant, Anti-inflammatory Studies, and Identification of Bioactive Compounds Using GC-MS of Ethanolic Novel Polyherbal Extract

Hyperglycemia is the hallmark of diabetes, which is a collection of related metabolic disorders. Over time, diabetes can cause a variety of problems, including cardiovascular disease, nephropathy, neuropathy, and retinopathy. Ethanolic novel polyherbal extract (PHE) was prepared by mixing equal amounts of the following ingredients: Terminalia chebula Retz. (TC), Terminalia bellerica Roxb. (TB), Berberis aristata DC. (BA), Nyctanthes arbostratis L. (NA), Premna integrifolia L. (PI), and Andrographis paniculata Nees. (AP). Analysis of PHE results revealed phytochemicals like glycosides, flavonoids, alkaloids, tannins, phytosterols, and saponins. The aim of the study was to prepare an ethanolic extract of PHE using the cold maceration technique, and identify bioactive molecules from gas chromatography-mass spectrometry (GC-MS) analysis, and evaluate biological responses by using in vitro studies like antioxidant and anti-inflammatory activity. PHE was found to contain a total of 35 phytochemicals in GC-MS of which 22 bioactive compounds were obtained in good proportion. There are a few new ones, including 2-buten-1-ol, 2-ethyl-4-(2, 2, 3-trimethyl-3-cyclopenten-1-yl (17.22%), 1, 2, 5, 6-tetrahydrobenzonitrile (4.26%), 4-piperidinamine, 2, 2, 6, 6-tetramethyl-(0.07%), undecanoic acid, 5-chloro-, chloromethyl ester (0.41%), are identified. Antioxidant activity was estimated using EC₅₀ values of 392.143 µg/ml, which were comparable to the standard value of EC₅₀ 310.513 µg/ml obtained using DPPH. Antioxidant activity was estimated with EC₅₀ 392.143 µg/ml, comparable to standard EC₅₀ 310.513 µg/ml using DPPH. In vitro anti-inflammatory potential was found with IC₅₀ of 91.449 µg/ml, comparable to standard IC₅₀ 89.451 µg/ml for membrane stabilization and IC₅₀ of 36.940 µg/ml, comparable to standard IC₅₀ 35.723 µg/ml for protein denaturation assays. As a result, the findings of this study show an enrichment of bioactive phytochemicals that can be used to investigate biological activity. To better understand how diabetes receptors work, in silico studies like docking could be carried out.

Biosynthesis and biophysical elucidation of CuO nanoparticle from Nyctanthes arbor-tristis Linn Leaf

Copper oxide nanoparticles (CuO NPs) synthesis using an environmentally benign approach, as well as their antibacterial properties. Copper sulphate pentahydrate (CuSO₄.5H₂O) of different concentrations (2 mM, 5 mM and 10 mM) and aqueous Nyctanthes arbor-tristis leaf extract were used to make the CuO NPs. The synthesised CuO NPs are characterised by UV-vis spectroscopy, X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). UV-vis spectroscopy confirmed the presence of CuO NPs. The functional groups of the active components were identified using the FTIR spectra of the control (leaf extract) and CuO NPs. SEM pictures revealed that the particles were rectangular, truncated triangle and spherical in shape, with sizes ranging between 4.9 nm, 18.4 nm and 23.8 nm determined using X-ray diffraction. The antibacterial activity of the produced CuO NPs was further evaluated using the well diffusion method. By observing inhibition zones around each well, the nanoparticles were revealed to have broad antibacterial action against human pathogenic bacterial strains Escherichia coli and Staphylococcus aureus withs the 7 ± 0.70-mm and 7 ± 0.21-mm inhibitory zone size respectively followed by 08 μg/mL and 2.5 μg/mL MIC respectively. Thus, these outputs concluded that the CuO NPs exhibited miraculous effect and it might be boon towards nanomedical science, pharmaceuticals and health industries. KEY POINTS: • Biosynthesis of CuO nanoparticle • Multifaceted utilization • Broad spectrum antimicrobial activity.

Green Synthesis of Silver Nanoparticles Using Thespesia populnea Bark Extract for Efficient Removal of Methylene Blue (MB) Degradation via Photocatalysis with Antimicrobial Activity and for Anticancer Activity

The green synthesis method was used to effectively fabricate Ag-NPs by using Thespesia populnea bark extract. The structural, morphological, elemental composition, and optical properties of as-synthesized Ag-NPs were characterized by powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), transmission electron microscopy (TEM), and UV-Vis spectroscopy. Their photocatalytic efficiency as a photocatalyst was examined by degradation of methylene blue (MB) dye under direct sunlight irradiation. After 120 minutes of sunlight irradiation, Ag-NPs show photocatalytic degradation efficiency (DE percent) of 92%. The hydroxyl and superoxide radicals were found to be responsible for biodegradation. To the best of our acquaintance, this is the first research to use Ag-NPs as a photocatalyst for the efficient degradation of MB dye and its antimicrobial activity by using Thespesia populnea bark extract. The cytotoxic viability against SK-MEL cell line with a median inhibitory concentration (IC50) of 45 μL/mg proved its potent anticancer property. Based on the findings, the study revealed the significance of as-synthesized green Ag-NPs over other physically/chemically prepared Ag-NPs.

A Review on Silver Nanoparticles: Classification, Various Methods of Synthesis, and Their Potential Roles in Biomedical Applications and Water Treatment

Recent developments in nanoscience have appreciably modified how diseases are prevented, diagnosed, and treated. Metal nanoparticles, specifically silver nanoparticles (AgNPs), are widely used in bioscience. From time to time, various synthetic methods for the synthesis of AgNPs are reported, i.e., physical, chemical, and photochemical ones. However, among these, most are expensive and not eco-friendly. The physicochemical parameters such as temperature, use of a dispersing agent, surfactant, and others greatly influence the quality and quantity of the synthesized NPs and ultimately affect the material’s properties. Scientists worldwide are trying to synthesize NPs and are devising methods that are easy to apply, eco-friendly, and economical. Among such strategies is the biogenic method, where plants are used as the source of reducing and capping agents. In this review, we intend to debate different strategies of AgNP synthesis. Although, different preparation strategies are in use to synthesize AgNPs such as electron irradiation, optical device ablation, chemical reduction, organic procedures, and photochemical methods. However, biogenic processes are preferably used, as they are environment-friendly and economical. The review covers a comprehensive discussion on the biological activities of AgNPs, such as antimicrobial, anticancer anti-inflammatory, and anti-angiogenic potentials of AgNPs. The use of AgNPs in water treatment and disinfection has also been discussed in detail.

Characterization, Antimicrobial and Antioxidant Evaluation of Biofabricated Silver Nanoparticles from Endophytic Pantoea anthophila

Endophyte mediated nanoparticles fabrication were emerging as a new frontier in nanomedicines that produce high biocompatible and functionalized silver nanoparticles. In this study, silver nanoparticles were successfully biosynthesized from the extracellular extract of endophytic bacterium Pantoea anthophila isolated from the stem of Waltheria indica for the first time. The synthesized nanoparticles showed a strong absorption band at 410 nm in the UV-Visible range. The dynamic light scattering and zeta potential analysis indicated that the average particle size was 16 nm at 5.30 mV. FTIR spectrum displayed the presence of various functional groups at 3423.65, 1633.71, 1022.27, 607.58 cm-1 that stabilised the nanoparticle. X-ray diffraction peaks were conferred to 100, 200, 220 and 311 planes of a face centred cubic structure. TEM and SEM micrograph revealed the spherical-shaped, polycrystalline nature with the presence of elemental silver analysed by EDAX. Selected area electron diffraction also confirms the orientation of silver nanoparticles with X-ray diffraction analysis. Antimicrobial activity against 10 different human pathogenic bacteria and fungi showed a broad spectrum inhibition against both Gram-positive and Gram-negative bacteria. Among the bacterial pathogens, B. Subtilis exhibited low activity compared to other pathogens. C. albicans was greatly controlled than other fungal species. A strong free radical scavenging activity of silver nanoparticles with IC50 values 31.29 ± 0.73, 19.83 ± 1.57, 35.64 ± 0.94, 42.07 ± 1.30, 29.70 ± 2.26, 29.10 ± 0.82, 36.80 ± 0.63 μg/ml was obtained in different antioxidant assays that were comparable to the reference. The study suggests that the silver nanoparticles can be biosynthesized from endophytic P. anthophila metabolites with significant therapeutic potential. With proper validation, the biosynthesized silver nanoparticles can be developed as a promising antiviral and anticancer drug candidate.