Green and cost effective synthesis of silver nanoparticles from endangered medicinal plant Withania coagulans and their potential biomedical properties

Updated Review of Metal Nanoparticles Fabricated by Green Chemistry Using Natural Extracts: Biosynthesis, Mechanisms, and Applications

Metallic nanoparticles have found wide applications due to their unique physical and chemical properties. Green biosynthesis using plants, microbes, and plant/microbial extracts provides an environmentally friendly approach for nanoparticle synthesis. This review discusses the mechanisms and factors governing the biosynthesis of metallic nanoparticles such as silver, gold, and zinc using various plant extracts and microorganisms, including bacteria, fungi, and algae. The phytochemicals and biomolecules responsible for reducing metal ions and stabilizing nanoparticles are discussed. Key process parameters like pH, temperature, and precursor concentration affecting particle size are highlighted. Characterization techniques for confirming the formation and properties of nanoparticles are also mentioned. Applications of biosynthesized nanoparticles in areas such as antibacterial delivery, cancer therapy, biosensors, and environmental remediation are reviewed. Challenges in scaling up production and regulating nanoparticle properties are addressed. Power Point 365 was used for creating graphics. Overall, green biosynthesis is an emerging field with opportunities for developing eco-friendly nanomanufacturing platforms using abundant natural resources. Further work on optimizing conditions, standardizing protocols, and exploring new biosources is needed to realize the full potential of this approach.

Withania frutescens (L.) Pauquy, a valuable Mediterranean shrub containing bioactive withanolides

The bushy plant Withania frutescens (L.) Pauquy is well distributed in the West-Mediterranean area, notably in the south of Spain, Algeria and Morocco where is it is used traditionally for the treatment of various human diseases, including diabetes. Unlike the two major species W. somnifera and W. coagulans extensively studied, the genomically close species W. frutescens has been much less investigated. Nevertheless, this shrub species displays a comparable phytochemical profile and marked antioxidant and anti-inflammatory properties, at the origin of reported pharmacological effects and its traditional uses. Here we have analyzed the diversity of biological effects reported with leaves and root extracts of W. frutescens. Hydroalcoholic extracts prepared from the aerial parts of the plant have revealed antihyperglycemic and cell-protective activities along with antimicrobial and anticorrosive effects. The extracts contained diverse polyphenolic compounds and a few alkaloids (calystegines) but most of the observed effects have been attributed to the presence of withanolides which are modified C28 ergostane-type steroids. Our analysis focused in part on specific withanolides found in W. frutescens, in particular an unusual 3-O-sulfated withanolide considered as a potential pro-drug of the major active compound withaferin A (WA) and a lead compound for the development of a potential drug candidate. The mechanism of action of this sulfated WA analogue is discussed. Altogether, our unprecedented extensive analysis of W. frutescens highlighted the pharmacological potential of this atypical medicinal plant. By analogy with the major cultivated Withania species, the market potential of little-known plant is underlined.

Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential

This research work aims to synthesize environmentally benign and cost-effective metal nanoparticles. In this current research scenario, the leaf extract of Cedrela toona was used as a reducing agent to biosynthesize silver nanoparticles (AgNPs). The synthesis of AgNPs was confirmed by the color shift of the reaction mixture, i.e., silver nitrate and plant extract, from yellow to dark brown colloidal suspension and was established by UV-visible analysis showing a surface plasmon resonance band at 434 nm. Different experimental factors were optimized for the formation and stability of AgNPs, and the optimum conditions were found to be 1 mM AgNO3 concentration, a 1:9 ratio of extract/precursor, and an incubation temperature of 70°C for 4 h. The Fourier transform infrared spectroscopy spectra indicated the presence of phytochemicals in the leaf extract that played the role of bioreducing agents in forming AgNPs. X-ray diffraction patterns confirmed the presence of AgNPs with a mean size of 25.9 nm. The size distribution and morphology of AgNPs were investigated by scanning electron microscopy, which clearly highlighted spherical nanoparticles with a size distribution of 22–30 nm with a mean average size of 25.5 nm. Moreover, prominent antibacterial activity was found against Enterococcus faecalis (21 ± 0.5 mm), Bacillus subtilis (20 ± 0.9 mm), Pseudomonas aeruginosa (18 ± 0.3 mm), Staphylococcus aureus (16 ± 0.7 mm), Klebsiella pneumoniae (16 ± 0.3 mm), and Escherichia coli (14 ± 0.7 mm). In addition, antioxidant activity was determined by DPPH and ABTS assays. Higher antioxidant activity was reported in AgNPs compared to the plant extract in both DPPH (IC50 = 69.62 µg·ml−1) and ABTS assays (IC50 = 47.90 µg·ml−1). Furthermore, cytotoxic activity was also investigated by the MTT assay against MCF-7 cells, and IC50 was found to be 32.55 ± 0.05 µg·ml−1. The crux of this research is that AgNPs synthesized from the Cedrela toona leaf extract could be employed as antibacterial, antioxidant, and anticancer agents for the treatment of bacterial, free radical-oriented, and cancerous diseases.

Green-route synthesis and ab-initio studies of a highly efficient nano photocatalyst:Ce/zinc-oxide nanopetals

In the present work, Zinc-oxide nanostructures and Ce/Zinc-oxide nanopetals were synthesized by a new environmentally friendly green synthesis method using the Withania coagulans plant. Cerium nitrate Ce(NO3)3 and zinc nitrate Zn(NO3)2 were used as precursors. The prepared nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet spectroscopy (UV-vis). Crystal planes (100), (002), (101), (102), (110), (103), (200), (112) and (201) at 2θ 31.75°, 34.35°, 36.2°, 47.55°, 56.6°, 62.75°, 66.3°, 67.9°, and 69.09° respectively confirmed the hexagonal wurtzite crystal structure of Zinc-oxide. Angular shifts for Ce1% doped Zinc-oxide and Ce3% doped Zinc-oxide nanopetal nanostructures were observed in the (100) and (101) planes of the crystal. More specifically, using Scherrer's equation, the crystallite sizes of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 16.48 ± 02 nm, 17.8 ± 2 nm, 18.8 ± 2 nm, and 18.87 ± 2 nm, respectively. The pure Zinc-oxide grain had the appearance of a nanoflower. On the other hand, the nanopetal structure of Ce5% doped Zinc-oxide nanopetals had oval-shaped nanopetal morphology. The absorption peaks were observed at 373, 376.4, 377, and 378 nm for Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals, respectively, which results in a progressive redshift. The gap energies of Zinc-oxide, Ce1% doped Zinc-oxide nanopetals, Ce3% doped Zinc-oxide nanopetals, and Ce5% doped Zinc-oxide nanopetals were 2.796, 2.645, 2.534, and 2.448 eV, respectively. Photodegradation under visible light (>400 nm) indicates the high efficiency of the photocatalyst based on Ce5% doped Zinc-oxide nanopetals. DFT calculations, structural changes, charge analysis, and electronic band structures were carried out to confirm the experiment.

Analytical Strategies to Investigate Molecular Signaling, Proteomics, Extraction and Quantification of Withanolides - A Comprehensive Review

Withanolides are the class of steroidal molecules getting greater emphasis in recent years. Quality control throughout the manufacturing and storage period is often one of the key problems that have restricted their broad use in India's indigenous and Ayurvedic medical systems for thousands of years. Because of their diverse clinical potential, withanolides have received a great deal of scientific attention. Analytical techniques are being devised for the automated isolation, identification, and estimation of every single protein within the cell as well as in herbal extracts of withanolides, due to which now researchers are interested in determining the effects of metabolism as well as various stimuli on protein expression, which made the study easier. This study discusses the potential use of hyphenated analytical methods that are reliable in understanding the molecular signaling features, proteome evaluation and characterization of withanolides, in addition to examining existing methodological limitations. The choice of analytical techniques for the withanolides analysis, however, relies on the nature of the sample matrix, the aim of the analysis, and the sensitivity of the technique.

Enhanced photocatalytic activity and antiviral evaluation of CuO@Fe2O3NC for amoxicillin degradation and SARS-CoV-2 treatment

Copper oxide nanoparticles (CuO NPs) and CuO NPs decorated with hematite (Fe2O3) nanocomposites (CuO@Fe2O3NC) were biosynthesized by a green method usingPortulaca oleracealeaves extract. The NC were characterized using various techniques, including x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and UV-vis spectroscopy. The results showed that the synthesized CuO and CuO@Fe2O3NC were crystalline with a monoclinic crystal structure and contained functional groups responsible for catalytic activity. The size of the nanocomposites ranged from 39.5 to 45.9 nm, and they exhibited a variety of agglomerated or aggregated shapes. The CuO@Fe2O3NC showed improved photocatalytic activity for the degradation of antibiotics in water and wastewater and promising antiviral activity against SARS-CoV-2, indicating its potential for use in disinfection applications. The study investigated the impact of irradiation time on the photocatalytic degradation of Amoxicillin and found that increasing the irradiation time led to a higher degradation rate. The band gap energy (Eg) for pure CuO NPs was around 2.4 eV and dropped to 1.6 eV with CuO@Fe2O3NC. In summary, the CuO@Fe2O3NC has the potential to be an efficient photocatalyst and promising antiviral agent for environmental remediation. The CuO@Fe2O3nanocomposites have been found to possess a high degree of efficacy in inactivating SARS-CoV-2 infectivity. The results of the study indicate that the nanocomposites exhibit potent anti-viral properties and hold significant potential for use in mitigating the spread of the virus.

Nanofabrication synthesis and its role in antibacterial, anti-inflammatory, and anticoagulant activities of AgNPs synthesized by Mangifera indica bark extract

The bio-based nanoparticles synthesis and assessment of their potential biomedical applications related research is rapidly emerging. The ability of an aqueous ethanolic bark extract of Mangifera indica to synthesize silver nanoparticles (AgNPs) as well as its antibacterial, anti-inflammatory, and anticancer activities were investigated in this study. Interestingly, the bark extract effectively synthesized the AgNPs, including an absorbance peak at 412 nm and sizes ranging from 56 to 89 nm. The Fourier Transform Infrared spectroscopy (FTIR) analysis confirmed that the presence of most essential functional groups belongs to the most bioactive compounds. Synthesized AgNPs showed fine antibacterial activity against the Urinary Tract Infection (UTI) causing bacterial pathogens such as Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus saprophyticus at 50 μg mL-1 concentrations. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against these pathogens were found as 12.5 ± 0.8 & 13 ± 0.6, 13.6 ± 0.5 & 14 ± 0.7, 11.5 ± 0.3 & 11.5 ± 0.4, 13 ± 0.8 & 13 ± 0.7, and 11.8 ± 0.4 & 12 ± 0.8 μg mL-1 respectively. Interestingly, this AgNPs also possesses outstanding anti-inflammatory and anticancer activities as studied against the egg albumin denaturation (85%) inhibition and MCF 7 (Michigan Cancer Foundation-7: breast cancer cells) cell line (cytotoxicity: 80.1%) at 50 μg mL-1 concentration. Similarly at 50 μg mL-1 concentration showed 75% of DPPH radical scavenging potential. These activities were dose dependent, and the findings suggest that the M. indica bark aqueous ethanolic extract synthesized AgNPs can be used as antibacterial, anti-inflammatory, and anticancer agents after in-vivo testing.

Comparative In Vitro Anticancer Study of Cisplatin Drug with Green Synthesized ZnO Nanoparticles on Cervical Squamous Carcinoma (SiHa) Cell Lines

In this article, we aimed to develop a unique treatment approach to cure cervical cancer without harming healthy normal cells and overcome the limitations of currently available therapies/treatments. Recently, chemotherapeutics based on metal oxides have gained attention as a promising approach for treating cancer. Herein, ZnO nanoparticles were synthesized with the leaf extract of Azadirachta indica. These green synthesized ZnO nanoparticles were used for a cytotoxic study on the cervical squamous carcinoma cell line SiHa and murine macrophage cell line RAW 264.7. Moreover, a hemolytic assay was performed to check the biocompatibility of ZnO nanoparticles. The biosynthesized ZnO nanoparticles were labeled as L1, L2, L5, and L10 nanoparticles. Various assays like crystal violet, MTT assay, and AO/PI dual staining method were performed to assess the anticancer potential of ZnO. The concentration of ZnO nanoparticles was taken in the range of 100-250 μg/mL in the in vitro anticancer study on SiHa cancer cell lines. The findings of the MTT assay revealed that biosynthesized ZnO nanoparticles exhibited significant cytotoxicity against SiHa cancer cell lines dose-dependently at two incubation times (24 and 48 h). Also, a decrease in cell viability was observed with an increased concentration of ZnO. The IC₅₀ values obtained were 141 μg/mL for L1, 132 μg/mL for L2, 127 μg/mL for L5, and 115 μg/mL for L10 nanoparticles. In addition, cisplatin drug (10 μg/mL) was also used to compare the anticancer activity with the biosynthesized L1, L2, L5, and L10 nanoparticles. The results of the crystal violet assay and AO/PI dual staining method revealed that morphological changes like cell shrinkage, poor cell adhesion, and induction of apoptosis occurred in the SiHa cancer cell lines. Furthermore, the stability of the ZnO nanoparticles at physiological pH has been assessed by recording the UV-visible spectrum at various pH values. Hence, the overall findings suggested that biosynthesized ZnO nanoparticles can be utilized for cervical squamous cancer treatment in addition to the current treatment strategies/techniques.

Silver Nanoparticles Synthesized from Abies alba and Pinus sylvestris Bark Extracts: Characterization, Antioxidant, Cytotoxic, and Antibacterial Effects

In recent years, phytofunctionalized AgNPs have attracted great interest due to their remarkable biological activities. In the present study, AgNPs were synthesized using Abies alba and Pinus sylvestris bark extracts. The chemical profile of these bark extracts was analyzed by LC-HRMS/MS. As a first step, the synthesis parameters (pH, AgNO₃ concentration, ratio of bark extract and AgNO₃, temperature, and reaction time) were optimized. The synthesized AgNPs were characterized by ATR-FTIR spectroscopy, DLS, SEM, EDX, and TEM. Their antioxidant, cytotoxic, and antibacterial properties were evaluated by the DPPH, ABTS, MTT, and broth microdilution assays, respectively. Abies alba and Pinus sylvestris bark extract-derived AgNPs were well-dispersed, spherical, small (average particle size of 9.92 and 24.49 nm, respectively), stable (zeta potential values of -10.9 and -10.8 mV, respectively), and cytotoxic to A-375 human malignant melanoma cells (IC₅₀ = 2.40 ± 0.21 and 6.02 ± 0.61 μg/mL, respectively). The phytosynthesized AgNPs also showed antioxidant and antibacterial effects.

Green synthesis and characterization of Solanum xanthocarpum capped silver nanoparticles and its antimicrobial effect on multidrug-resistant bacterial (MDR) isolates

Plant extracts and their bioactive compounds are considered as the promising options for green synthesis of nanoparticles instead expensive and hazardous materials. Here, Solanum xanthocarpum fruit was used for synthesis of silver nanoparticles (AgNP). The synthesized AgNPs were characterized by using chromatographic and spectroscopic analytical methods. AgNPs were confirmed by UV-visible absorbance at 420-470 nm. TEM analysis showed AgNP with 22.45 nm average size. X-ray diffraction studies revealed the crystalline and face central cubic nature of AgNPs. FTIR analysis revealed functional group present over AgNPs. The aminodiphenyl acetic acid, clomipramine, and fonisopril from fruit extracts were found to be major capping agents on AgNPs as a result of analysis by HRLC-MS. All clinical isolates showed resistance for ampicilline, amoxyclav, niladixic acid, and sulphafurazole, suggesting multidrug resistance. The results showed that all isolates were sensitive to AgNPs synthesized fruit extracts. On the contrary, all isolates were resistant to whole S. xanthocarpum fruit extracts alone. The antimicrobial activity of AgNP was explored against multidrug-resistant (MDR) Gram-negative clinical isolates including Escherichia coli, Shigella spp., Aeronomonas spp. and Pseudomonas spp. MIC values ranged between 1.25 mg/ml and 2.5 mg/ml at 8 McFarland's standards. Minimum bactericidal concentration was found to be in between 2.5 mg/ml to 5 mg/ml. Nanoparticles synthesized from fruit extract of S. xanthocarpum containing aminodiphenyl acetic acid, clomipramine, and fonisopril metabolites exhibit promising antimicrobial activity against MDR Gram-negative clinical isolates.

Green Synthesis of Silver Nanoparticles Using Salvia verticillata and Filipendula ulmaria Extracts: Optimization of Synthesis, Biological Activities, and Catalytic Properties

The study's objective was to obtain silver nanoparticles (SVAgNP and FUAgNP) using aqueous extracts of Salvia verticillata and Filipendula ulmaria. The optimal conditions for nanoparticle synthesis were determined and obtained; nanoparticles were then characterized using UV-Vis, Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). SVAgNP and FUAgNP possessed a crystalline structure with 48.42% and 60.41% silver weight, respectively. The highest percentage of nanoparticles in the solution had a diameter between 40 and 70 nm. In DPPH˙ and ABTS˙⁺ methods, FUAgNP (IC₅₀ 15.82 and 59.85 µg/mL, respectively) demonstrated a higher antioxidant capacity than SVAgNP (IC₅₀ 73.47 and 79.49 µg/mL, respectively). Obtained nanoparticles also showed pronounced antibacterial activity (MIC ˂ 39.1 µg/mL for most of the tested bacteria), as well as high biocompatibility with the human fibroblast cell line MRC-5 and significant cytotoxicity on some cancer cell lines, especially on the human colon cancer HCT-116 cells (IC₅₀ 31.50 and 66.51 µg/mL for SVAgNP and FUAgNP, respectively). The nanoparticles demonstrated high catalytic effectiveness in degrading Congo red dye with NaBH₄. The results showed a rapid and low-cost methodology for the synthesis of AgNPs using S. verticillata and F. ulmaria with promising biological potential.

Novel archetype in cancer therapeutics: exploring prospective of phytonanocarriers

This paper reports various types of cancer, their incidence, and prevalence all over the globe. Along with the discovery of novel natural drugs for cancer treatment, these present a promising option which are eco-friendly, safe, and provide better acceptability in comparison to synthetic agents that carries multiple side effects. This paper provides an idea about various nanocarriers and phytochemicals, along with how their solubility and bioavailability can be enhanced in nanocarrier system. This report combines the data from various literature available on public domain including PubMed on research articles, reviews, and along with report from various national and international sites. Specialized metabolites (polyphenols, alkaloids, and steroids etc) from medicinal plants are promising alternatives to existing drugs. Studies have suggested that the treatment of cancer using plant products could be an alternative and a safe option. Studies have shown with the several cell lines as well as animal models, that phytomolecules are important in preventing/treating cancer. Phytochemicals often outperform chemical treatments by modulating a diverse array of cellular signaling pathways, promoting cell cycle arrest, apoptosis activation, and metastatic suppression, among others. However, limited water solubility, bioavailability, and cell penetration limit their potential clinical manifestations. The development of plant extract loaded nanostructures, rendering improved specificity and efficacy at lower concentrations could prove effective. Nanocarriers, such as liposomes, nanostructured lipids, polymers, and metal nanoparticles, have been tested for the delivery of plant products with enhanced effects. Recent advances have achieved improvement in the the stability, solubility, bioavailability, circulation time, and target specificity by nanostructure-mediated delivery of phytochemicals. Nanoparticles have been considered and attempted as a novel, targeted, and safe option. Newer approaches such as phyto-nanocarriers with carbohydrates, lignin, and polymers have been considered even more selective and effective modes of drug delivery in biomedical or diagnostic applications.

Advances of Cobalt Nanomaterials as Anti-Infection Agents, Drug Carriers, and Immunomodulators for Potential Infectious Disease Treatment

Infectious diseases remain the most serious public health issue, which requires the development of more effective strategies for infectious control. As a kind of ultra-trace element, cobalt is essential to the metabolism of different organisms. In recent decades, nanotechnology has attracted increasing attention worldwide due to its wide application in different areas, including medicine. Based on the important biological roles of cobalt, cobalt nanomaterials have recently been widely developed for their attractive biomedical applications. With advantages such as low costs in preparation, hypotoxicity, photothermal conversion abilities, and high drug loading ability, cobalt nanomaterials have been proven to show promising potential in anticancer and anti-infection treatment. In this review, we summarize the characters of cobalt nanomaterials, followed by the advances in their biological functions and mechanisms. More importantly, we emphatically discuss the potential of cobalt nanomaterials as anti-infectious agents, drug carriers, and immunomodulators for anti-infection treatments, which might be helpful to facilitate progress in future research of anti-infection therapy.

The effect of AgNPS bio-functionalization on the cytotoxicity of the yeast Saccharomyces cerevisiae

This work used Sedum praealtum leaf extract to synthesize silver nanoparticles (AgNPs) in a single step. The cytotoxicity of AgNPs was studied with the yeast Saccharomyces cerevisiae W303-1. In addition, the antioxidant activity of the DPPH radical was studied both in the extract of S. praealtum and in the AgNPs. UV-Vis spectroscopy determined the presence of AgNPs by the location of the surface plasmon resonance (SPR) band at 434 nm. TEM and XRD analyzes show AgNPs with fcc structure and hemispherical morphology. Also, AgNPs range in size from 5 to 25 nm and have an average size of 14 nm. 1H NMR, FTIR, and UV-Vis spectroscopy techniques agreed that glycosidic compounds were the main phytochemical components responsible for the reduction and stabilization of AgNPs. In addition, AgNPs presented a maximum of 12% toxicity in yeast attributed to the generation of ROS. Consequently, there was low bioactivity because glycoside compounds cover the biosynthesized AgNPs from S. praealtum. These findings allow applications of AgNPs involving contact with mammals and higher organisms.

Comparing the Anticancer Activities of Green-Synthesized Ginsenoside and Transformed Ginsenoside Nanoconjugates (Ag, Au, and Pt)

Aim: To assess the anticancer activity of nanoparticles synthesized via a green method using American ginseng (AG). Methods: Stem-leaf saponins from AG (SAG) and heat-transformed stem-leaf saponins from AG (TSAG) were used to synthesize different SAG nanoparticles (SAG-NPs) and TSAG nanoparticles (TSAG-NPs). The NPs were characterized, and their anticancer activity was assessed in vitro. Results: The NPs, which differed in size (16.69 nm∼253.8 nm), were spherical or polyhedral with a low PDI and good stability. The TSAG-NPs inhibited cancer cells by inhibiting proliferation, promoting cancer cell apoptosis and directly leading cancer cells to necrosis. The small cell lung cancer cell line (SCLC) NCI-H446 was the most sensitive to the TSAG-AgNPs, with an IC50 value of 20.71±2.38 μg/mL, and the TSAG-AgNPs inhibited invasiveness and reduced the risk of metastasis. Conclusion: TSAG-AgNPs, selected from many SAG-NPs and TSAG-NPs, are sensitive to SCLC and provide a new approach to the currently limited treatment.

Optimization of Synthesis of Silver Nanoparticles Conjugated with Lepechinia meyenii (Salvia) Using Plackett-Burman Design and Response Surface Methodology—Preliminary Antibacterial Activity

In the present investigation, an ethanolic fraction (EF) of Lepechinia meyenii (salvia) was prepared and fractionated by gradient column chromatography, and the main secondary metabolites present in the EF were identified by HPLC-MS. Silver nanoparticles (AgNPs) were synthesized and conjugated with the EF of Lepechinia meyenii (salvia). The AgNPs synthesis was optimized using Plackett-Burman design and response surface methodology (RSM), considering the following independent variables: stirring speed, synthesis pH, synthesis time, synthesis temperature and EF volume. The AgNPs synthesized under the optimized conditions were characterized by UV visible spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM). The antibacterial activity of the AgNPs against Staphylococcus aureus (ATCC® 25923) was evaluated. The following flavonoids were identified: rosmarinic acid, diosmin and hesperetin-7-O-rutinoside. The optimized conditions for the synthesis of nanoparticles were pH 9.45, temperature 49.8 °C, volume of ethanolic fraction 152.6 µL and a reaction time of 213.2 min. The obtained AgNPs exhibited an average size of 43.71 nm and a resonance plasmon of 410–420 nm. Using FT-IR spectroscopy, the disappearance of the peaks between 626.50 and 1379.54 cm−1 was evident with the AgNPs, which would indicate the participation of these functional groups in the synthesis and protection of the nanoparticles. A hydrodynamic size of 47.6 nm was obtained by DLS, while a size of 40–60 nm was determined by STEM. The synthesized AgNPs conjugated with the EF showed a higher antibacterial activity than the EF alone. These results demonstrate that the AgNPs synthesized under optimized conditions conjugated with the EF of the Lepechinia meyenii (salvia) presented an increased antibacterial activity.

Co-Combination of Pregabalin and Withaniacoagulans-Extract-Loaded Topical Gel Alleviates Allodynia and Hyperalgesia in the Chronic Sciatic Nerve Constriction Injury for Neuropathic Pain in Animal Model

The current study reports the fabrication of co-combination gel using Pregabalin and Withania coagulans fruit extract to validate its effectiveness for neuropathic pain in chronic constriction injury (CCI) rat models. Three topical gels were prepared using Carbopol 934 through a pseudo-ternary phase diagram incorporating the Pregabalin (2.5%), Withania coagulans extract (2%), and co-combination of both Pregabalin (2.5%) and Withania coagulans extract (2%). Gels were characterized. FTIR showed a successful polymeric network of the gel without any interaction. The drug distribution at the molecular level was confirmed by XRD. The AFM images topographically indicated the rough surface of gels with a size range from 0.25 to 330 nm. DSC showed the disappearance of sharp peaks of the drug and extract, showing successful incorporation into the polymeric network of gels. The in vitro drug release of co-combination gel was 73% over 48 h. The mechanism of drug release by combination gel was Higuchi+ fickian with values of n (0.282) and R2 (0.947). An in vivo study for pain assessment via four methods: (i) heat hyperalgesia, (ii) cold allodynia, (iii) mechano-hyperalgesia, and (iv) dynamic mechano-allodynia, confirmed that topical treatment with co-combination gel reduced the pain significantly as indicated by the p value: R1 (p < 0.001), R2 (p < 0.001), R3 (p < 0.015), and R4 (p < 0.0344). The significance order was R2 (****) > R1 (***) > R3 (**) > R4 (*) > R5 (ns).

Green Synthesis of a Novel Silver Nanoparticle Conjugated with Thelypteris glandulosolanosa (Raqui-Raqui): Preliminary Characterization and Anticancer Activity

In the last decade, the green synthesis of nanoparticles has had a prominent role in scientific research for industrial and biomedical applications. In this current study, silver nitrate (AgNO3) was reduced and stabilized with an aqueous extract of Thelypteris glandulosolanosa (Raqui-raqui), forming silver nanoparticles (AgNPs-RR). UV-vis spectrophotometry, dynamic light scattering (DLS), and scanning transmission electron microscopy (STEM) were utilized to analyze the structures of AgNPs-RR. The results from this analysis showed a characteristic peak at 420 nm and a mean hydrodynamic size equal to 39.16 nm, while the STEM revealed a size distribution of 6.64–51.00 nm with an average diameter of 31.45 nm. Cellular cytotoxicity assays using MCF-7 (ATCC® HTB-22™, mammary gland breast), A549 (ATCC® CCL-185, lung epithelial carcinoma), and L929 (ATCC® CCL-1, subcutaneous connective tissue of Mus musculus) demonstrated over 42.70% of MCF-7, 59.24% of A549, and 8.80% of L929 cells had cell death after 48 h showing that this nanoparticle is more selective to disrupt neoplastic than non-cancerous cells and may be further developed into an effective strategy for breast and lung cancer treatment. These results demonstrate that the nanoparticle surfaces developed are complex, have lower contact angles, and have excellent scratch and wear resistance.

Preparation, Characterization of Pregabalin and Withania coagulans Extract-Loaded Topical Gel and Their Comparative Effect on Burn Injury

The current study depicts the comparative effects of nanogel using Withania coagulans extract, pregabalin alone, and a co-combination gel. The gels prepared were then analyzed for conductivity, viscosity, spread ability, globule size, zeta potential, polydispersity index, and TEM. The globule size of the co-combination gel, determined by zeta sizer, was found to be (329 ± 0.573 nm). FTIR analysis confirms the successful development of gel, without any interaction. Drug distribution at the molecular level was confirmed by XRD. DSC revealed no bigger thermal changes. TEM images revealed spherical molecules with sizes of 200 nm for the co-combination gel. In vivo studies were carried out by infliction of third degree burn wounds on rat skin, and they confirmed that pregabalin and Withania coagulans heals the wound more effectively, with a wound contraction rate of 89.95%, compared to remaining groups. Anti-inflammatory activity (IL-6 and TNF-α), determined by the ELISA technique, shows that the co-combination gel group reduces the maximum inflammation with TNF-α value (132.2 pg/mL), compared to the control (140.22 pg/mL). Similarly, the IL-6 value was found to be (78 pg/mL) for the co-combination gel and (81 pg/mL) in the case of the control. Histopathologically, the co-combination gel heals wounds more quickly, compared to individual gel. These outcomes depict that a co-combination gel using plant extracts and drugs can be successfully used to treat burn injury.

Cyanobacteria: miniature factories for green synthesis of metallic nanomaterials: a review

Nanotechnology is one of the most promising and advanced disciplines of science that deals with synthesis, characterization and applications of different types of Nanomaterials (NMs) viz. nanospheres, nanoparticles, nanotubes, nanorods, nanowires, nanocomposites, nanoalloys, carbon dots and quantum dots. These nanosized materials exhibit different physicochemical characteristics and act as a whole unit during its transport. The unique characteristics and vast applications of NMs in diverse fields viz. electronics, agriculture, biology and medicine have created huge demand of different type of NMs. Conventionally physical and chemical methods were adopted to manufacture NMs which are expensive and end up with hazardous by-products. Therefore, green synthesis exploiting biological resources viz. algae, bacteria, fungi and plants emerged as a better and promising alternative due to its cost effective and ecofriendly approach and referred as nanobiotechnology. Among various living organisms, cyanobacteria have proved one of the most favourable bioresources for NMs biosynthesis due to their survival in diverse econiches including metal and metalloid contaminated sites and capability to withstand high levels of metals. Biosynthesis of metallic NMs is accomplished through bioreduction of respective metal salts by various capping agents viz. alkaloids, pigments, polysaccharides, steroids, enzymes and peptides present in the biological systems. Advancement in the field of Nanobiotechnology has produced large number of diverse NMs from cyanobacteria which have been used as antimicrobial agents against Gram positive and negative human pathogens, anticancer agents, luminescent nanoprobes for imaging of cells, antifungal agents against plant pathogens, nanocatalyst and semiconductor quantum dots in industries and in bioremediation in toxic pollutant dyes. In the present communication, we have reviewed cyanobacteria mediated biosynthesis of NMs and their applications in various fields.

Fabrication of Silver Nanoparticles Using Cordyline fruticosa L. Leave Extract Endowing Silk Fibroin Modified Viscose Fabric with Durable Antibacterial Property

The current work presented a green synthetic route for the fabrication of silver nanoparticles obtained from aqueous solutions of silver nitrate using Cordyline fruticosa L. leaf extract (Col) as a reducing and capping agent for the first time. The bio-synthesized silver nanoparticles (AgCol) were investigated using UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The obtained data demonstrated that AgCol in spherical shape with an average size of 28.5 nm were highly crystalline and well capped by phytocompounds from the Col extract. Moreover, the bio-synthesized AgCol also exhibited the effective antibacterial activities against six pathogenic bacteria, including Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella enterica (S. enterica), Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus) and Enterococcus faecalis (E. faecalis). The AgCol were applied as an antibacterial finishing agent for viscose fabric using a pad-dry curing technique. The AgCol-treated viscose fabrics exhibited a good synergistic antimicrobial activity against E. coli and S. aureus bacteria. Furthermore, the silk fibroin regenerated from Bombyx mori cocoon waste was utilized as an ecofriendly binder for the immobilization of AgCol on the viscose fabric. Thus, the antimicrobial efficacy of the AgCol and fibroin modified viscose fabric still reached 99.99% against the tested bacteria, even after 30 washing cycles. The colorimetric property, morphology, elemental composition, and distribution of AgCol on the treated fabrics were investigated using several analysis tools, including colorimetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectroscopy (AAS), Kjeldahl, and FTIR. Because of the excellent antimicrobial efficiency and laundering durability, as well as the green synthesis method, the AgCol and fibroin modified viscose fabric could be utilized as an antibacterial material in sportswear and medical textile applications.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.

Therapeutic potential of biogenic and optimized silver nanoparticles using Rubia cordifolia L. leaf extract

Rubia cordifolia L. is a widely used traditional medicine in the Indian sub-continent and Eastern Asia. In the present study, the aqueous leaf extract of the R. Cordifolia was used to fabricate silver nanoparticles (RC@AgNPs), following a green synthesis approach. Effect of temperature (60 °C), pH (8), as well the concentration of leaf extract (2 ml) and silver nitrate (2 mM) were optimized for the synthesis of stable RC@AgNPs. The phytofabrication of nanosilver was validated by UV–visible spectral analysis, which displayed a distinctive surface plasmon resonance peak at 432 nm. The effective functional molecules as capping and stabilizing agents, and responsible for the conversion of Ag⁺ to nanosilver (Ag⁰) were identified using the FTIR spectra. The spherical RC@AgNPs with an average size of ~ 20.98 nm, crystalline nature, and 61% elemental composition were revealed by TEM, SEM, XRD, and. EDX. Biogenic RC@AgNPs displayed a remarkable anticancer activity against B16F10 (melanoma) and A431 (carcinoma) cell lines with respective IC₅₀ of 36.63 and 54.09 µg/mL, respectively. Besides, RC@AgNPs showed strong antifungal activity against aflatoxigenic Aspergillus flavus, DNA-binding properties, and DPPH and ABTS free radical inhibition. The presented research provides a potential therapeutic agent to be utilized in various biomedical applications.

Medicinal plants mediated the green synthesis of silver nanoparticles and their biomedical applications

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Green nano synthesis is a rapidly expanding field of interest in nanotechnology due to its feasibility, low toxicity, eco‐friendly nature, and long‐term viability. Some plants have long been used in medicine because they contain a variety of bioactive compounds. Silver has long been known for its antibacterial properties. Silver nanoparticles have taken a special place among other metal nanoparticles. Silver nanotechnology has a big impact on medical applications like bio‐coating, novel antimicrobial agents, and drug delivery systems. This review aims to provide a comprehensive understanding of the pharmaceutical qualities of medicinal plants, as well as a convenient guideline for plant‐based silver nanoparticles and their antimicrobial activity.

Withania somnifera: Progress towards a Pharmaceutical Agent for Immunomodulation and Cancer Therapeutics

Chemotherapy is one of the prime treatment options for cancer. However, the key issues with traditional chemotherapy are recurrence of cancer, development of resistance to chemotherapeutic agents, affordability, late-stage detection, serious health consequences, and inaccessibility. Hence, there is an urgent need to find innovative and cost-effective therapies that can target multiple gene products with minimal adverse reactions. Natural phytochemicals originating from plants constitute a significant proportion of the possible therapeutic agents. In this article, we reviewed the advances and the potential of Withania somnifera (WS) as an anticancer and immunomodulatory molecule. Several preclinical studies have shown the potential of WS to prevent or slow the progression of cancer originating from various organs such as the liver, cervix, breast, brain, colon, skin, lung, and prostate. WS extracts act via various pathways and provide optimum effectiveness against drug resistance in cancer. However, stability, bioavailability, and target specificity are major obstacles in combination therapy and have limited their application. The novel nanotechnology approaches enable solubility, stability, absorption, protection from premature degradation in the body, and increased circulation time and invariably results in a high differential uptake efficiency in the phytochemical’s target cells. The present review primarily emphasizes the insights of WS source, chemistry, and the molecular pathways involved in tumor regression, as well as developments achieved in the delivery of WS for cancer therapy using nanotechnology. This review substantiates WS as a potential immunomodulatory, anticancer, and chemopreventive agent and highlights its potential use in cancer treatment.

Functionalization and Antibacterial Applications of Cellulose-Based Composite Hydrogels

Pathogens, especially drug-resistant pathogens caused by the abuse of antibiotics, have become a major threat to human health and public health safety. The exploitation and application of new antibacterial agents is extremely urgent. As a natural biopolymer, cellulose has recently attracted much attention due to its excellent hydrophilicity, economy, biocompatibility, and biodegradability. In particular, the preparation of cellulose-based hydrogels with excellent structure and properties from cellulose and its derivatives has received increasing attention thanks to the existence of abundant hydrophilic functional groups (such as hydroxyl, carboxy, and aldehyde groups) within cellulose and its derivatives. The cellulose-based hydrogels have broad application prospects in antibacterial-related biomedical fields. The latest advances of preparation and antibacterial application of cellulose-based hydrogels has been reviewed, with a focus on the antibacterial applications of composite hydrogels formed from cellulose and metal nanoparticles; metal oxide nanoparticles; antibiotics; polymers; and plant extracts. In addition, the antibacterial mechanism and antibacterial characteristics of different cellulose-based antibacterial hydrogels were also summarized. Furthermore, the prospects and challenges of cellulose-based antibacterial hydrogels in biomedical applications were also discussed.

Synergistic effect of plant extract coupled silver nanoparticles in various therapeutic applications- present insights and bottlenecks

The phytocomponent conjugated silver nanoparticles (AgNPs) have been extensively explored for various therapeutic applications such as antimicrobial, antioxidant, anticancer, anti-inflammatory, antidiabetic and anticoagulant effects. The bio-conjugation of Ag-based nanomaterial with plant extracts reduces their toxicity to biological systems and enhances their therapeutic effectiveness. The diversity of phytochemicals or capping agents provided by the plant extracts and the small size and large surface area of AgNPs permits maximum adsorption of these capping agents onto their surfaces that further promote the therapeutic performance of phytoconjugated AgNPs in various biomedical applications. The mechanistic action involved in antimicrobial and anticancer functions of AgNPs is mainly dependent on the induction of reactive oxygen species (ROS) resulting in cellular apoptosis and necrosis. This review summarizes the recent studies of various plant extract assisted synthesis of AgNPs, potential biomedical applications with the possible mechanism of action and major shortcomings affecting their therapeutic efficacy.

Silver Nanoparticles for Conductive Inks: From Synthesis and Ink Formulation to Their Use in Printing Technologies

Currently, silver nanoparticles have attracted large interest in the photonics, electrics, analytical, and antimicrobial/biocidal fields due to their excellent optical, electrical, biological, and antibacterial properties. The versatility in generating different sizes, shapes, and surface morphologies results in a wide range of applications of silver nanoparticles in various industrial and health-related areas. In industrial applications, silver nanoparticles are used to produce conductive inks, which allows the construction of electronic devices on low-cost and flexible substrates by using various printing techniques. In order to achieve successful printed patterns, the necessary formulation and synthesis need to be engineered to fulfil the printing technique requirements. Additional sintering processes are typically further required to remove the added polymers, which are used to produce the desired adherence, viscosity, and reliable performance. This contribution presents a review of the synthesis of silver nanoparticles via different methods (chemical, physical and biological methods) and the application of silver nanoparticles under the electrical field. Formulation of silver inks and formation of conductive patterns by using different printing techniques (inkjet printing, screen printing and aerosol jet printing) are presented. Post-printing treatments are also discussed. A summary concerning outlooks and perspectives is presented at the end of this review.

Melt electrowritten poly(caprolactone) lattices incorporated with silver nanoparticles for directional water transport antibacterial wound dressings

The composite dressing has excellent antibacterial ability and directional water transport effect, showing potential application in wound care.

Evaluation of silver nanoparticles in cosmeceutical and potential biosafety complications

Silver nanoparticles are well received in the cosmeceutical industry due to their broad spectrum of pharmacology applications. Research on the therapeutic properties exhibited by silver nanoparticles revealed that the antimicrobial and anti-inflammatory properties are the main attraction in the establishment of nanocosmeceutical products whereby their mechanisms of action are reviewed in this paper. In addition, studies on other uses of silver nanoparticles acknowledged that the particles act as antifungal agents in nail polishes and pigments in coloured beauty products such as lipsticks and eye shadows. Despite the extensive use of silver nanoparticles in the cosmetic line, there are still limited resources on the mechanism of actions and the effect of the particles on the bio-functionality of the body. The safety of silver nanoparticles could be comprehended from their skin penetration ability and toxicity to the human body in which it could be justified that both features are mainly influenced by the morphology of the particles and the method of application. This article summarizes exclusively on the synthesis of silver nanoparticles, the biomedical mechanisms and applications as well the limitations with respect to skin penetration ability and toxicity effects which will contribute significantly to the vast research on the association of nanotechnology and cosmetics.

Phyto-Functionalized Silver Nanoparticles Derived from Conifer Bark Extracts and Evaluation of Their Antimicrobial and Cytogenotoxic Effects

Silver nanoparticles synthesized using plant extracts as reducing and capping agents showed various biological activities. In the present study, colloidal silver nanoparticle solutions were produced from the aqueous extracts of Picea abies and Pinus nigra bark. The phenolic profile of bark extracts was analyzed by liquid chromatography coupled to mass spectrometry. The synthesis of silver nanoparticles was monitored using UV-Vis spectroscopy by measuring the Surface Plasmon Resonance band. Silver nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopy, Raman spectroscopy, dynamic light scattering, scanning electron microscopy, energy dispersive X-ray and transmission electron microscopy analyses. The antimicrobial and cytogenotoxic effects of silver nanoparticles were evaluated by disk diffusion and Allium cepa assays, respectively. Picea abies and Pinus nigra bark extract derived silver nanoparticles were spherical (mean hydrodynamic diameters of 78.48 and 77.66 nm, respectively) and well dispersed, having a narrow particle size distribution (polydispersity index values of 0.334 and 0.224, respectively) and good stability (zeta potential values of -10.8 and -14.6 mV, respectively). Silver nanoparticles showed stronger antibacterial, antifungal, and antimitotic effects than the bark extracts used for their synthesis. Silver nanoparticles obtained in the present study are promising candidates for the development of novel formulations with various therapeutic applications.

Chemical Composition, Biological Activity, and Health-Promoting Effects of Withania somnifera for Pharma-Food Industry Applications

The Withania genus comes from the Solanaceae family and includes around 23 species, spread over some areas of the Mediterranean, Asia, and East Africa. Widely used in traditional medicine for thousands of years, these plants are rich in secondary metabolites, with special emphasis on steroidal lactones, named withanolides which are used as ingredients in numerous formulations for a plethora of diseases, such as asthma, diabetes, arthritis, impotence, amnesia, hypertension, anxiety, stress, cancer, neurodegenerative, and cardiovascular diseases, and many others. Among them, Withania somnifera (L.) Dunal is the most widely addressed species from a pharmacological and agroindustrial point of view. In this sense, this review provides an overview of the folk uses, phytochemical composition, and biological activity, such as antioxidant, antimicrobial, anti-inflammatory, and cytotoxic activity of W. somnifera, although more recently other species have also been increasingly investigated. In addition, their health-promoting effects, i.e., antistress, anxiolytic, adaptogenic, antirheumatoid arthritis, chemoprotective, and cardiorespiratory-enhancing abilities, along with safety and adverse effects are also discussed.

Phytochemistry, Food Application, and Therapeutic Potential of the Medicinal Plant (Withania coagulans): A Review

Herbal plants have been utilized to treat and cure various health-related problems since ancient times. The use of Ayurvedic medicine is very significant because of its least reported side effects and host of advantages. Withania coagulans (Family; Solanaceae), a valuable medicinal plant, has been used to cure abnormal cell growth, wasting disorders, neural as well as physical problems, diabetes mellitus, insomnia, acute and chronic hepatic ailments. This review provides critical insight regarding the phytochemistry, biological activities, and pharmacognostic properties of W. coagulans. It has been known to possess diuretic, anti-inflammatory, anti-bacterial, anti-fungal, cardio-protective, hepato-protective, hypoglycemic, anti-oxidative, and anti-mutagenic properties owing to the existence of withanolides, an active compound present in it. Apart from withanolides, W. coagulans also contains many phytochemicals such as flavonoids, tannins, and β-sterols. Several studies indicate that various parts of W. coagulans and their active constituents have numerous pharmacological and therapeutic properties and thus can be considered as a new drug therapy against multiple diseases.

Biomedical Applications of Chinese Herb-Synthesized Silver Nanoparticles by Phytonanotechnology

Recent advances in nanotechnology have opened up new avenues for the controlled synthesis of nanoparticles for biomedical and pharmaceutical applications. Chinese herbal medicine is a natural gift to humanity, and it has long been used as an antibacterial and anticancer agent. This study will highlight recent developments in the phytonanotechnological synthesis of Chinese herbal medicines to utilize their bioactive components in biomedical and therapeutic applications. Biologically synthesized silver nanoparticles (AgNPs) have emerged as a promising alternative to chemical and physical approaches for various biomedical applications. The comprehensive rationale of combinational or synergistic effects of Chinese herb-based AgNPs synthesis was investigated with superior physicochemical and biological properties, and their biomedical applications, including antimicrobial and anticancer activity and wound healing properties. AgNPs can damage the cell ultrastructure by triggering apoptosis, which includes the formation of reactive oxygen species (ROS), DNA disintegration, protein inactivation, and the regulation of various signaling pathways. However, the anticancer mechanism of Chinese herbal medicine-based AgNPs is more complicated due to the potential toxicity of AgNPs. Further in-depth studies are required to address Chinese herbs' various bioactive components and AgNPs as a synergistic approach to combat antimicrobial resistance, therapeutic efficiency of drug delivery, and control and prevention of newly emerged diseases.

Biogenic synthesis and characterization of selenium nanoparticles and their applications with special reference to antibacterial, antioxidant, anticancer and photocatalytic activity

Oxyanions of selenium, selenite (SeO₃)^2- and selenate (SeO₄)^2- are toxic to terrestrial and aquatic biota but few microorganisms including cyanobacteria are resistant to high levels of selenite. Cyanobacteria evade selenite toxicity through bioreduction and synthesis of selenium nanoparticles (SeNPs). In this study, extracellular biosynthesis of SeNPs (Se⁰) using cyanobacterium, Anabaena sp. PCC 7120 on exposure to sodium selenite and characterization was done by using UV-visible spectroscopy, SEM-EDX, TEM and FTIR analyses which confirmed spherical shape with size range of 5-50 nm diameter. These biogenic SeNPs demonstrated significant antibacterial and anti-biofilm activity against bacterial pathogens. Furthermore, these SeNPs showed high antioxidant activity at minimum concentration of 50 µg/mL and significant anti-proliferative activity against HeLa cell line with IC₅₀ value of 5.5 µg/mL. The SeNPs also induced accumulation of cancer cells in the sub-G1 phase which was clearly observed in cellular and nuclear morphology. These biofabricated SeNPs also reduced and decolorized toxic methylene blue dye significantly through photocatalytic degradation. Therefore Anabaena sp. PCC 7120 may be employed as a green bioresource to synthesize SeNPs with potential applications in medicine and environmental bioremediation.

Antiviral nanoparticles for sanitizing surfaces: A roadmap to self-sterilizing against COVID-19

Nanoparticles provide new opportunities in merging therapeutics and new materials, with current research efforts just beginning to scratch the surface of their diverse benefits and potential applications. One such application, the use of inorganic nanoparticles in antiseptic coatings to prevent pathogen transmission and infection, has seen promising developments. Notably, the high reactive surface area to volume ratio and unique chemical properties of metal-based nanoparticles enables their potent inactivation of viruses. Nanoparticles exert their virucidal action through mechanisms including inhibition of virus-cell receptor binding, reactive oxygen species oxidation and destructive displacement bonding with key viral structures. The prevention of viral outbreaks is one of the foremost challenges to medical science today, emphasizing the importance of research efforts to develop nanoparticles for preventative antiviral applications. In this review, the use of nanoparticles to inactivate other viruses, such as influenza, HIV-1, or norovirus, among others, will be discussed to extrapolate broad-spectrum antiviral mechanisms that could also inhibit SARS-CoV-2 pathogenesis. This review analyzes the published literature to highlight the current state of knowledge regarding the efficacy of metal-based nanoparticles and other antiviral materials for biomedical, sterile polymer, and surface coating applications.

Prospective Application of Nanoparticles Green Synthesized Using Medicinal Plant Extracts as Novel Nanomedicines

The use of medicinal plants in green synthesis of metal nanoparticles is increasing day by day. A simple search for the keywords "green synthesis" and "nanoparticles" yields more than 33,000 articles in Scopus. As of August 10, 2021, more than 4000 articles have been published in 2021 alone. Besides demonstrating the ease and environmental-friendly route of synthesizing nanomaterials, many studies report the superior pharmacological properties of green synthesized nanoparticles compared to those synthesized by other methods. This is probably due to the fact that bioactive molecules are entrapped on the surface of these nanoparticles. On the other hand, recent studies have confirmed the nano-dimension and biocompatibility of metal ash (Bhasma) preparations, which are commonly macerated with biological products and administered for the treatment of various diseases in Indian medicine since ancient times. This perspective article argues for the prospective medical application of green nanoparticles in the light of Bhasma.

The Action-Networks of Nanosilver: Bridging the Gap between Material and Biology

The emergence of nanosilver (silver in nanoscale shapes and their assemblies) benefits the landscape of modern healthcare; however, this brings about concerns over its safety issues associated with an ultrasmall size and high mobility. By reviewing previous reporting details about the synthesis and characterization of nanosilver and its biological responses, a gap between materials synthesis and their biomedical uses is characterized by the insufficient understanding of the interacting and interplaying nanoscale actions of silver. To improve reporting quality and advance clinical translations, it is suggested that researchers have a comprehensive recognition of the "Indications for use" before designing innovative nanosilver-based materials and an "Action-network" concept addressing the acting range and strength of those nanoscale actions is implemented. Although this discussion is specific to nanosilver, the idea of "Indications for use" centered design and synthesis is generally applicable to other biomedical nanomaterials.

Determination of Antioxidant Activity by Oxygen Radical Absorbance Capacity (ORAC-FL), Cellular Antioxidant Activity (CAA), Electrochemical and Microbiological Analyses of Silver Nanoparticles Using the Aqueous Leaf Extract of Solanum mammosum L

PURPOSE

The importance of studying polyphenolic compounds as natural antioxidants has encouraged the search for new methods of analysis that are quick and simple. The synthesis of silver nanoparticles (AgNPs) using plant extracts has been presented as an alternative to determine the total polyphenolic content and its antioxidant activity.

METHODS

In this study, aqueous leaf extract of Solanum mammosum, a species of plant endemic to South America, was used to produce AgNPs. The technique of oxygen radical absorption capacity using fluorescein (ORAC-FL) was used to measure antioxidant activity. The oxidation of the 2´,7´-dichlorodihydrofluorescein diacetate (DCFH2-DA) as fluorescent probe was used to measure cellular antioxidant activity (CAA). Electrochemical behavior was also examined using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Total polyphenolic content (TPH) was analyzed using the Folin-Ciocalteu method, and the major polyphenolic compound was analyzed by high performance liquid chromatography with diode array detector (HPLC/DAD). Finally, a microbial analysis was conducted using Escherichia coli and Bacillus sp.

RESULTS

The average size of nanoparticles was 5.2 ± 2.3 nm measured by high-resolution transmission electron microscopy (HR-TEM). The antioxidant activity measured by ORAC-FL in the extract and nanoparticles were 3944 ± 112 and 637.5 ± 14.8 µM ET/g of sample, respectively. Cellular antioxidant activity was 14.7 ± 0.2 for the aqueous extract and 12.5 ± 0.2 for the nanoparticles. The electrochemical index (EI) was 402 μA/V for the extract and 324 μA/V for the nanoparticles. Total polyphenolic content was 826.6 ± 20.9 and 139.7 ± 20.9 mg EGA/100 g of sample. Gallic acid was the main polyphenolic compound present in the leaf extract. Microbiological analysis revealed that although leaf extract was not toxic for Escherichia coli and Bacillus sp., minor toxic activity for AgNPs was detected for both strains.

CONCLUSION

It is concluded that the aqueous extract of the leaves of S. mammosum contains nontoxic antioxidant compounds capable of producing AgNPs. The methods using AgNPs can be used as a fast analytical tool to monitor the presence of water-soluble polyphenolic compounds from plant origin. Analysis and detection of new antioxidants from plant extracts may be potentially applicable in biomedicine.

Green Synthesis of Silver Nanoparticles Using Extract of Artemisia absinthium L., Humulus lupulus L. and Thymus vulgaris L., Physico-Chemical Characterization, Antimicrobial and Antioxidant Activity

The novelty of this study is twofold: AgNPs were obtained and characterized using Artemisia absinthium (A. absinthium), Humulus lupulus (H. lupulus), and Thymus vulgaris (T. vulgaris) plants extracts; moreover, a green and environmentally friendly approach for the synthesis of silver nanoparticles (AgNPs) using aqueous extracts was developed. This paper discusses new approaches about the synthesis of AgNPs. T. vulgaris, H. lupulus, and A. absinthium, which are renewable and common plants, perfect as reducing, stabilizing, and capping agent for green synthesis of silver nanoparticles (AgNPs). The extracts and synthesized AgNPs were characterized by various physico-chemical, phytochemical, morphological scanning electron microscope (SEM/EDS) and transmission electron microscope scanning (TEM), and antibacterial activity. The antioxidant activity of extracts and AgNPs were also assessed by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), 2,2-diphenyl-1-picrylhydrazyl (DPPH•), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), and trifluoperazine dihydrochloride (TFPH•) scavenging assays. Extracts/AgNPs showed significant antioxidant activity in all cases. A. absinthium/AgNPs, H. lupulus/AgNPs, and T. vulgaris /AgNPs displayed activities against DPPH• (0.14 ± 0.00; 0.11 ± 0.00 and 0.14 ± 0.00 mmol/g), ABTS•+ (0.55 ± 0.05; 0.86 ± 0.05 and 0.55 ± 0.05 mmol/g), respectively. TEM analysis confirmed the average particle size, it estimated t A. absinthium/AgNPs–46 nm, H. lupulus/AgNPs size of synthesized particles was 42 nm and T. vulgaris/AgNPs–48 nm. SEM analysis revealed that T. vulgaris/AgNPs showed in solitary cases as snowflake-like, branched, but in a general spheric shape, H. lupulus/AgNPs were wedge-shaped, and A. absinthium/AgNPs were the spherical shape of the synthesized AgNPs. EDS analysis confirmed the purity of the synthesized AgNPs with a strong signal at 3.2 keV. A. absinthium/AgNPs, H. lupulus/AgNPs, and T. vulgaris/AgNPs exhibited higher antibacterial activity against all tested bacterial strains compared to their respective pure extracts. It is concluded that AgNPs synthesized in extracts have a broad range of biological applications, which can be used as an eco-friendly material without having negative effects on the environment.