Anticandidal activity of greenly synthesized silver nanoparticles formulated using Alkanna tinctoria roots against multidrug resistant candidal pathogens

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.

Nanotechnology deals with the synthesis of nanoparticles with controlled size, shape and dispersity of materials at the nanometer scale and their potential use for human well bein g. This leads to focus on “Green Synthesis” of nanoparticles which seems to be an easy, efficient and eco- friendly approach. In this study, the green synthesis of silver nanoparticles was carried out using root extract of Morinda pubescens as reducing agent. It was found that aqueous silver ions can be reduced by aqueous root extr act of Morinda pubescens to generate extremely stable silver nanoparticles in water. The silver nanoparticles (AgNPs) formation was confirmed by the colour change of the mixture and further confirmed by spectral analysis. UV-Visible spectrum of the aqueous medium containing silver nanoparticles showed a peak around 416.5 nm. FT -IR analysis confirmed reduction of Ag+ ions to Ag0 ions in synthesized silver nanoparticles. Further, the produced silver nanoparticles showed bactericidal effect against Staphylococcus aureus, Escherichia coli and Aspergillus niger. From this study concluded that the root extract of Morinda pubescens reduces Ag+ to Ag0 and enhances synthesis of silver nanoparticles with antimicrobial activity.

A simple and rapid synthesis of silver nanoparticles was achieved using the aqueous extract of Ficus benghalensis leaf as both reducing and stabilizing agents. Reaction kinetics of the bioreduction process was investigated to understand the effects of various parameters such as silver ion concentrations, volume of leaf extract, pH of the reaction mixture and reaction duration. The biosynthesized silver nanoparticles were characterized by employing various techniques such as Ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, scanning electron microscopy and transmission electron microscopy. The obtained silver nanoparticles showed face- centered cubic phase and found to have the spherical shape with an average size of 28.69 nm as respectively observed from XRD and TEM analysis. The biogenic silver nanoparticles showed excellent antimicrobial activity against the multi-drug resistant pathogens such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis and Staphylococcus aureus, which is comparable with the standard broad spectrum antibiotic streptomycin. Further, the biosynthesized silver nanoparticles were explored for the functionalization of glass slide without using any binding agents, which showed the strong resistance against the growth of biofilm forming Proteus mirabilis.

Sumac (Rhuscoriaria L., family Anacardiaceae) is rich in bioactive components like tannins and phenolic compounds, exhibiting antioxidant properties. Green synthesis of silver nanoparticles (SAgNP) offers eco-friendly and cost-effective production methods. In this study, the effect of Sumac nano silver particles (SAgNP) on lead pharmacokinetics was assessed. Green synthesis of silver nanoparticles involved adding 25 ml of sumac extract to 200 ml of 1 mM silver nitrate solution under hot stirring. Twenty-one male albino rats were randomly divided into three groups: lead group (60 mg/kg of lead acetate orally), crude group (100 mg/kg of crude sumac extract orally), and nano group (100 mg/kg of SAgNP orally followed by lead acetate). Results demonstrated successful SAgNP formation and significant reduction (p≤0.05) in blood lead concentration after 6 hours, suggesting SAgNP's potential in lowering lead levels. SAgNP exhibited stronger efficacy than crude extract in reducing blood lead concentrations. Green synthesis of silver nanoparticles offers a safe, cost-effective, and environmentally friendly approach with promising applications in mitigating lead toxicity.

Green synthesis is the synthesis of nanoparticles using biological systems and is greatly beneficial because of its non-toxicity and eco-friendly behaviour. This study focuses on the green synthesis of silver nanoparticles using Aloe vera gel extract and Abelmoschus esculentus extract and its characterization and antibacterial activity. The synthesized nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and UV- Vis Spectroscopy. The bio-reduction of aqueous Ag+ ions by these extracts were identified by their colour change. The change in colour indicates the formation of AgNPs (Silver Nanoparticles). Silver nanoparticles showed maximum absorbance at 250nm in both Aloe vera gel extract and Abelmoschus esculentus. A peak obtained at this point confirmed the presence of AgNPs. Moreover, the synthesized silver nanoparticle showed potential antibacterial activity against the selective strains of bacteria such as Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes which were studied using the well-diffusion method. This study gives a scope for its potential applications in biomedical field.

Here, green synthesis of silver nanoparticles (NPs) using aqueous extract of Scrophularia Striata was demonstrated. In order to obtain the best formation conditions of NPs, different physicochemical parameters such as volume of the extract, silver ion concentration, temperature and reaction time were studied. Synthesized resultant NPs were characterized using UV, SEM, TEM, EDX, XRD, FT-IR and DLS analyses. A color change to brown after adding the extract to the silver nitrate solution was observed which indicated the formation of silver NPs. The synthesized silver NPs by Scrophularia Striata extract showed the highest absorbance at 426 nm. Plants use as stabilizing and reducing agents for NPs, due to their antioxidant properties and many secondary compounds.

The emergence of multidrug-resistant pathogens has increased the urgency for alternative treatment options for infections like cystitis. This study focused on the green synthesis of silver nanoparticles and cysteine-conjugated silver nanoparticles utilizing Melaleuca lanceolata leaf extract, optimized via artificial neural networks for controlled nanoparticle size. The ANN model provided precise prediction and control of nanoparticle size, reducing experimental variability. The characterization was performed using UV-Vis spectroscopy, which showed peaks at 445nm for AgNPs and 405nm for Cys-AgNPs. Additionally, FTIR, SEM, and EDX analysis confirmed the successful synthesis of AgNPs and their conjugation with cysteine. Biological analyses revealed that Cys-AgNPs had increased antioxidant and anti-inflammatory effects over AgNPs and controls. Notably, they demonstrated better antibacterial activity against Staphylococcus nepalensis, a new uropathogen causing cystitis, with a 17mm inhibitory zone and a lowest inhibitory concentration of 25µg/ml. Direct cytotoxicity assays and in vivo studies in animal models were not carried out, but the observed reduction in hemolysis in vitro demonstrates that it may be biocompatible. These results demonstrate the novelty of using ANN-based optimization and green nanotechnology to produce stable, functionalized nanoparticles of therapeutic interest. It is recommended that cytotoxicity analyses, in vivo confirmation, and wider MDR pathogen testing should be performed in the future to ensure clinical relevance.

The consumption of foods contaminated with various foodborne organisms such as, viruses, fungi and bacteria are recognized as the important sources of foodborne illness in animals and humans. Multidrug resistant foodborne bacteria increased morbidity, mortality rates, and severe economic loss and associated with prolong hospitalization. The development of natural and novel antibacterial agent is much needed as there is an increasing concern on multidrug resistant bacteria. This study aimed to synthesize silver nanoparticles using aqeous Pisum sativum L. (pea) pod extract and to characterize the nanoparticles. It was further used on various drug resistant foodborne bacterial pathogens and antimicrobial activity was determined. The synergistic antibacterial activity, antioxidant activity and biocompatibility were also assessed. Green synthesized nanoparticles applied in this study were synthesized using aqueous P. sativum L. (pea) pod extract with particle size 30 nm. The green synthesized silver nanoparticles showed antimicrobial activity against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 700802, Streptococcus gordonii ATCC 49818, Staphylococcus aureus (MRSA) ATCC 4330 and Staphylococcus aureus ATCC 25923. Among the pathogenic bacterial strains, silver nanoparticles were highly active against S. aureus ATCC 25923 than other bacterial strains (22 ± 2 mm). The antibacterial activity varied between 15 ± 2 mm and 22 ± 2 mm diameter zone of inhibition. The MIC value of the nanoparticles ranged from 6.25 µg/mL to 75 µg/mL and MBC value ranged from 50 µg/mL to 150 µg/mL. The green synthesized nanoparticles showed antioxidant potential. Normal fibroblast cell lines (L-929) was used to test the cytotoxic activity and the increased IC50 value (750.5 ± 5.5 μg/mL) indicated good biological compatibility. The present findings revealed that green synthesized silver nanoparticles exhibited potent activity against various food borne pathogenic bacteria. These nanoparticles might be well developed as novel antibacterial substances for the treatment of food borne multidrug resistant bacterial infection.

Rapid spread of antimicrobial drug resistance is alarming and demands a sustainable solution. Green synthesis of silver nanoparticles can pave the way for the development of adjuvants that can help overcome bacterial drug resistance. In the current study, green synthesis of silver nanoparticles utilizing pea (Pisum sativum) peels and their evaluation against multidrug-resistant (MDR) bacterial pathogens has been proposed. Pea peels were extracted and analyzed for antioxidant potential by non-enzymatic DPPH assay. The extract was used to prepare silver nanoparticles (gAgNPs) characterized using UV-VIS spectroscopy, SEM, FTIR, and zeta sizer, and evaluated for antibacterial activity. The SEM showed that the gAgNPs were spherical with a size of 59.24 nm ± 0.3, and the zeta sizer gave a PDI of 0.2. As adjuvants, these gAgNPs in combination with vancomycin showed a superior antibacterial activity against vancomycin-resistant E. faecalis (zone of inhibition= 66 mm ± 0.41) and vancomycin-resistant P. aeruginosa (35 mm ± 1.41) as compared to vancomycin. Hemolysis was IC50= 998.44 μg/mL, creating a therapeutic window for IC50 =5 μg/mL, effective against human pathogens. This study suggests these gAgNPs could be a good lead to work as adjuvants with vancomycin against vancomycin-resistant Gram-positive and Gram-negative clinical bacteria and thus warrants further studies.

Background: The growing resistance of oral pathogens to conventional antimicrobial agents has created a demand for innovative, natural alternatives in dental care. Ocimum tenuiflorum and Ocimum gratissimum are widely recognized for their medicinal properties, particularly their antimicrobial potential. This study investigates the green synthesis of silver nanoparticles (AgNPs) using these herbal extracts and their incorporation into a dental varnish. The varnish underwent comprehensive characterization using Fluorescent analysis, NMR analysis, Zeta potential studies and UV-Vis spectroscopy to evaluate its structural and physicochemical properties. Methods: Silver nanoparticles were synthesized using Ocimum tenuiflorum and Ocimum gratissimum herbal extracts via a green synthesis approach. The synthesized AgNPs were incorporated into a dental varnish and their antibacterial efficacy was tested against Staphylococcus aureus, Streptococcus mutans, Lactobacillus sp., Enterococcus faecalis and Escherichia coli. The antibacterial activity was evaluated using the agar well diffusion method and time-kill curve assay. Inhibition zones were measured at concentrations of 25 µg/mL, 50 µg/mL and 100 µg/mL and results were compared with a commercially available dental varnish. Results: The AgNP-based dental varnish demonstrated superior antibacterial activity across all tested concentrations. The inhibition zones for S. aureus were 10 mm, 14 mm and 26 mm at 25 µg/mL, 50 µg/mL and 100 µg/mL, respectively, outperforming the commercial varnish's 9 mm inhibition zone. For S. mutans, the Ocimum-based varnish showed inhibition zones of 24 mm, 27 mm and 34 mm, which significantly exceeded the standard varnish's 9 mm. Lactobacillus sp. exhibited inhibition zones of 20 mm, 22 mm and 31 mm, while E. faecalis showed 9 mm, 11 mm and 14 mm. E. coli displayed the highest inhibition zones of 27 mm, 30 mm and 35 mm, compared to the 9 mm zone produced by the commercial varnish. The time-kill curve assay demonstrated that the Ocimum-based varnish at 100 µg/mL effectively reduced bacterial counts of E. coli and S. mutans to 10 CFU/mL within 5 hours. Similar reductions were observed for S. aureus, Lactobacillus sp. and E. faecalis, indicating potent bactericidal activity with increasing concentrations. Conclusion: The Ocimum-mediated AgNP dental varnish exhibited superior antibacterial efficacy compared to the commercial dental varnish, particularly at 100 µg/mL. The enhanced antibacterial activity, combined with the eco-friendly green synthesis process, suggests that Ocimum tenuiflorum and Ocimum gratissimum-based AgNPs hold promising potential as effective and safe alternatives in dental care for combating oral pathogens. Further in vivo studies are recommended to evaluate the varnish’s clinical performance and long-term safety.

The recent research in nanoparticles synthesis field utilizes biological synthesis rather than chemical and physical methods in order to get uniform size and non-toxic of nanoparticles, further in biological synthesis the microbial synthesis is time consuming and requires sterilized conditions wherein green synthesis can overcome these drawbacks. The green synthesis of silver nanoparticles from many plant extracts finding quit attraction to many research scholars though very minute work has been done by using Hibiscus leaf extract. In this research work comparative experimental investigation is done on green synthesis of silver nanoparticles from three extracts Hibiscus leaf extract, followed by characterization was done by UV-Spectrophotometer, XRD, FTIR, AFM and SEM analysis. The silver nanoparticles of size 25-50 nm were synthesized by Hibiscus leaf extract. The silver nanoparticles were later treated with 4 different antibiotics wherein erythromycin showed three-fold increments in its efficiency.

The science of nanotechnology and nanoparticles is the manipulation of matter on atomic and molecular weight, the nanotechnology and nanomaterial’s refer to the particular technological goal which is precise manipulation of atom and molecules for used the fabrication process of microbial products and it is now concern to as molecular nanotechnology, it also known as the nanotechnology is science of designing, making and application of nano-structure and nanomaterials also used investigation of relationship various properties of materials with their nanometer dimensions. The exploitation of various plant materials for the biosynthesis of silver nano particles is considered a green technology. Because it does not involves any harmful chemicals. Nanotechnology field is one of the most attractive researches. The field of nanotechnology is applied to bio materials. Nanoparticles are generally considered as particles with a size up to 100 nm, that have completely new or improved properties as compared to the bulk material that they are collected based on particular characteristics such as size, distribution and morphology. Different groups of unorganized parts of the plants have been utilizing for the green synthesis of silver nanoparticles, in the present work the fresh leaves of euphorbia umbellate have been used for the synthesis of silver nanoparticles. Synthesis of AgNPs employing either microorganisms or plant extracts has emerged as an alternative approach. Silver nanoparticles is embedded with antibacterial properties because of its unique properties is considered in medical science, the main aim of work is green synthesis of silver nanoparticles using Euphorbia Umbellate leaf extract and its antibacterial activity, after the collection of sample, identification and extraction of Euphorbia Umbellate was performed the production of silver nanoparticles.

Among the various types of nanoparticles and their strategy for synthesis, the green synthesis of silver nanoparticles has gained much attention in the biomedical, cellular imaging, cosmetics, drug delivery, food, and agrochemical industries due to their unique physicochemical and biological properties. The green synthesis strategies incorporate the use of plant extracts, living organisms, or biomolecules as bioreducing and biocapping agents, also known as bionanofactories for the synthesis of nanoparticles. The use of green chemistry is ecofriendly, biocompatible, nontoxic, and cost-effective. We shed light on the recent advances in green synthesis and physicochemical properties of green silver nanoparticles by considering the outcomes from recent studies applying SEM, TEM, AFM, UV/Vis spectrophotometry, FTIR, and XRD techniques. Furthermore, we cover the antibacterial, antifungal, and antiparasitic activities of silver nanoparticles.

Chapter 1 - Green route synthesis of silver nanoparticles (Ag-NPs) and their applications

Objectives: To investigate the potential of nanoparticles synthesized from neem leaves in pest management for Bactrocera dorsalis. Methods: This study involves extracting the insecticidal properties of neem (Azadirachta indica) by fermenting air-dried leaves with rice wash. The crude fermented neem extract (FNE) was applied as a biopesticide against male B. dorsalis in an improvised olfactometer. The remaining crude extract was utilized in the green synthesis of silver nanoparticles (AgNP) and copper nanoparticles (CuNP). The insecticidal activities of FNE and the extracts with AgNP and CuNP were tested against B. dorsalis. Findings: The experimental treatments 100% FNE and 20% FNECuNP have the same effect as the positive control, causing the death of adult male fruit fly of 83.33% mortality rate after 24 h. The treatment 20% FNE-AgNP showed a higher mortality rate, 100%, after 24 h. Likewise, the results of the larvicidal activities infer that the most effective treatment with a mortality rate of 100% after 24-h exposure is the extract with silver nanoparticles. Moreover, the neem extract, FNE-AgNP, and FNE-CuNP exhibited ovicidal properties, suppressing the development of eggs into third instar larvae. Fermented neem extract can be used to formulate biopesticide enhanced with nanoparticles for controlling B. dorsalis. Novelty: This study showed that the fermented neem leaves extract using rice wash is effective in the green synthesis of silver and copper nanoparticles. The prepared biopesticide metal nanoparticles can be used in the management of B. dorsalis. Keywords: Silver nanoparticles; Copper nanoparticles; Insecticidal; Bactrocera dorsalis; Azadirachta indica