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

Comparative Evaluation of Antioxidative and Anti-inflammatory Properties of Acerola-Mediated Silver Nanogel and Copper Oxide Nanogel

BACKGROUND

The tropical plant acerola of the genus Malpighia includes shrubs and trees with fruit that is high in nutrients and bioactive chemicals. Acerola stands out due to its exceptionally high ascorbic acid content, ranging from 1500 to 4500 mg/100 g. Vitamin C intake greatly influences gingival health. The addition of nanoparticles along with vitamin C-rich acerola exhibits high antioxidant and anti-inflammatory properties, thereby positively improving gingival health.

METHOD

The antioxidant and anti-inflammatory properties of aqueous extracts of the acerola plant (Malpighia emarginata) were assessed. Silver nanoparticles (AgNPs) and copper oxide nanoparticles (CuONPs) were synthesized using the aqueous extract of acerola cherry gel by the phytogenic fabrication method. The antioxidant potential of silver and copper nanoparticles was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide, ferric reducing antioxidant power (FRAP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and nitric oxide scavenging activities.

RESULTS

Increasing concentrations of nanoparticles showed an increase in scavenging activity. Overall, CuONPs and AgNPs exhibited remarkable radical quenching efficacies. The anti-inflammatory effectiveness of CuONPs and AgNPs was monitored, showing suppression of protein denaturation as demonstrated by bovine serum albumin (BSA), egg albumin (EA), and membrane stabilization assays. The results revealed that increasing the doses of CuONPs and AgNPs had a positive impact on the anti-inflammatory activity of the nanoparticles.

CONCLUSION

The present study revealed that both nanoparticles provided better antioxidant and anti-inflammatory activities. This study also elaborates on the pharmacological potential of both nanoparticles, which could be further explored for application in all healthcare sectors.

Synthesis of Berberis aristate rhizome extract stabilized magnesium nanoparticles using green chemistry: rhizome characterization, in vitro antimicrobial and anti-inflammatory activity

In the present study, magnesium nanoparticles (Mg NPs) were synthesized utilizing an aqueous extract of Berberis aristate rhizome and evaluated for antimicrobial and anti-inflammatory activity. Technofunctional properties of rhizome powder were evaluated and during thermal stability evaluation four stages of decomposition with a maximum delta Y value of 76.04 % was observed. Optimization of Mg NPs was carried out by employing eight different concentrations (C1-C8)   and the C4 showed maximum absorbance at 330 nm confirming the NPs synthesis. The Mg NPs showed the particle size of 62 nm, zeta potential of -24.7 mV and hexagonal mprphology. Potential inhibition against S. aureus and E. coli (76.78 ± 0.05% and 74.62 ± 0.17%)and anti-inflammatory activity ranging from 42.43 ± 0.07-82.92 ± 0.04% was observed for Mg NPs. Therefore, green synthesis of Mg NPs is a promising approach for the development ofbiological active NPs to cure microbial infections.

Characterization, Synthesis, and Biological Activities of Silver Nanoparticles Produced via Green Synthesis Method Using Thymus Vulgaris Aqueous Extract

Introduction

Silver nanoparticles (AgNPs) have been found to exhibit unique properties which show their potential to be used in various therapies. Green synthesis of AgNPs has been progressively gaining acceptance due to its cost-effectiveness and energy-efficient nature.

Objective

In the current study, aqueous extract of Thymus vulgaris (T. vulgaris) was used to synthesize the AgNPs using green synthesis techniques followed by checking the effectiveness and various biological activities of these AgNPs.

Methods

At first, the plant samples were proceeded for extraction of aqueous extracts followed by chromatography studies to measure the phenolics and flavonoids. The synthesis and characterization of AgNPs were done using green synthesis techniques and were confirmed using Fourier transform infra-red (FT-IR) spectroscopy, UV-visible spectroscopy, scanning electron microscope (SEM), zeta potential, zeta sizer and X-Ray diffraction (XRD) analysis. After confirmation of synthesized AgNPs, various biological activities were checked.

Results

The chromatography analysis detected nine compounds accounting for 100% of the total amount of plant constituents. The FT-IR, UV-vis spectra, SEM, zeta potential, zeta sizer and XRD analysis confirmed the synthesis of AgNPs and the variety of chemical components present on the surface of synthesized AgNPs in the plant extract. The antioxidant activity of AgNPs showed 92% inhibition at the concentration of at 1000 µg/mL. A greater inhibitory effect in anti-diabetic analysis was observed with synthesized AgNPs as compared to the standard AgNPs. The hemolytic activity was low, but despite low concentrations of hemolysis activity, AgNPs proved not to be toxic or biocompatible. The anti-inflammatory activity of AgNPs was observed by in-vitro and in-vivo approaches in range at various concentrations, while maximum inhibition occurs at 1000 µg (77.31%).

Conclusion

Our data showed that the potential biological activities of the bioactive constituents of T. vulgaris can be enhanced through green synthesis of AgNPs from T. vulgaris aqueous extracts. In addition, the current study depicted that AgNPs have good potential to cure different ailments as biogenic nano-medicine.

Antibacterial potential of biosynthesized silver nanoparticles using Nepeta sessilifolia Bunge and Salvia hydrangea DC. ex Benth. extracts from the natural habitats of Iran's Rangelands

BACKGROUND

Nowadays, the use of herbal extracts for the production of nanoparticles has attracted a lot of attention due to the fast reaction, economy, and compatibility with the environment. The aim of the present study is the biosynthesis of silver nanoparticles from the extracts of Nepeta sessilifolia Bunge and Salvia hydrangea DC. ex Benth. and their antibacterial activity was measured.

METHODS

For this purpose, the flowering branch of N. sessilifolia and the flower of S. hydrangea were randomly collected from three places, respectively, from the rangelands of Aqdash Mountain and Biabe in Isfahan province, Iran in May 2021. After extracting aqueous extracts by hot method, silver nanoparticles were synthesized by the biological method. Green synthesized silver nanoparticles were analyzed by UV-Vis spectroscopy, XRD, FTIR, and FESEM-EDAX. The antibacterial effect was evaluated by diffusion method in agar and determination of minimum growth inhibitory and lethal concentration (MIC and MBC) by dilution method in liquid culture medium.

RESULTS

Based on the results of UV-Vis spectroscopy, silver nanoparticles synthesized from N. sessilifolia and S. hydrangea had distinct absorption peaks at wavelengths of 407 to 424 nm and 414 to 415 nm, respectively. The crystalline nature of these synthetic silver nanoparticles was confirmed by XRD. FESEM analysis showed that the size of biosynthesized silver nanoparticles from N. sessilifolia and S. hydrangea extracts were 10-50 nm and 10-80 nm, respectively, and were cubic. The results of diffusion in agar showed that the largest diameter of the growth inhibition zone belonging to the synthetic silver nanoparticles from both extracts of N. sessilifolia (~ 26.00 mm) and S. hydrangea (~ 23.50 mm) was against Gram-positive bacteria Staphylococcus aureus. The most vigorous killing activity by synthetic silver nanoparticles from N. sessilifolia extract was against Klebsiella pneumoniae with a value of 250 μg/mL, two times stronger than rifampin.

CONCLUSION

Therefore, the studied extracts can be suitable options for fast and safe green synthesis of silver nanoparticles effective against some bacterial strains. These synthetic silver nanoparticles can be used as possible options and have strong potential for the production of natural antibiotics.

Biosynthesis, characterization, and investigation of antimicrobial and cytotoxic activities of silver nanoparticles using Solanum tuberosum peel aqueous extract

Metallic nanoparticle biosynthesis is thought to offer opportunities for a wide range of biological uses. The green process of turning biological waste into utilizable products gaining attention due to its economical and eco-friendly approach in recent years. This study reported the ability of Solanum tuberosum (ST) peel extract to the green synthesis of non-toxic, stable, small-sized silver nanoparticles without any toxic reducing agent utilizing the phytochemical components present in its structure. UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, flourier scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and energy dispersive analysis X-ray confirmed the biosynthesis and characterization of silver nanoparticles. Also, dynamic light scattering and thermogravimetric analyses showed stable synthesized nanoparticles. The antibacterial activity of the biosynthesized silver nanoparticles was evaluated against four different bacterial strains, Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) Bacillus subtilis (B. subtilis), and a yeast, Candida albicans (C. albicans) using the minimum inhibitory concentration technique. The cytotoxic activities were determined against Human dermal fibroblast (HDF), glioblastoma (U118), colorectal adenocarcinoma (CaCo-2), and human ovarian (Skov-3) cell lines cancer cells using MTT test. The nanoparticle capping agents that could be involved in the reduction of silver ions to Ag NPs and their stabilization was identified using FTIR. Nanoparticles were spherical in shape and had a size ranging from 3.91 to 27.07 nm, showed crystalline nature, good stability (-31.3 mV), and the presence of capping agents. ST-Ag NPs significantly decreased the growth of bacterial strains after treatment. The in vitro analysis showed that the ST-Ag NPs demonstrated dose-dependent cytotoxicity against cell lines. Based on the data, it is feasible to infer that biogenic Ag NPs were capped with functional groups and demonstrated considerable potential as antibacterial and anticancer agents for biomedical and industrial applications.

Phytochemical Synthesis of Silver Nanoparticles and Their Antimicrobial Investigation on Cotton and Wool Textiles

The use of bio-based reagents for silver nanoparticle (AgNP) production has gained much attention among researchers as it has paved the way for environmentally friendly approaches at low cost for synthesizing nanomaterials while maintaining their properties. In this study, Stellaria media aqueous extract was used for silver nanoparticle phyto-synthesis, and the resulting treatment was applied to textile fabrics to test its antimicrobial properties against bacteria and fungi strains. The chromatic effect was also established by determining the L*a*b* parameters. For optimizing the synthesis, different ratios of extract to silver precursor were tested using UV-Vis spectroscopy to observe the SPR-specific band. Moreover, the AgNP dispersions were tested for their antioxidant properties using chemiluminescence and TEAC methods, and the phenolic content was evaluated by the Folin-Ciocâlteu method. For the optimal ratio, values of average size, 50.11 ± 3.25 nm, zeta potential, -27.10 ± 2.16 mV, and polydispersity index, 0.209, were obtained via the DLS technique and zeta potential measurements. AgNPs were further characterized by EDX and XRD techniques to confirm their formation and by microscopic techniques to evaluate their morphology. TEM measurements revealed cvasi-spherical particles with sizes in the range of 10-30 nm, while SEM images confirmed their uniform distribution on the textile fiber surface.

Silver Nanoparticles of Artemisia sieberi Extracts: Chemical Composition and Antimicrobial Activities

BACKGROUND

Artemisia sieberi (mugwort) is a member of the daisy family Asteraceae and is widely propagated in Saudi Arabia. A. sieberi has historical medical importance in traditional societies. The current study aimed to assess the antibacterial and antifungal characteristics of the aqueous and ethanolic extracts of A. sieberi. In addition, the study investigated the effect of silver nanoparticles (AgNPs) synthesized from the A. sieberi extract.

METHODS

The ethanolic and aqueous extracts and AgNPs were prepared from the shoots of A. sieberi. The characteristics of AgNPs were assessed by UV-visible spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The antibacterial experiments were performed against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The fungal species used were Candida parapsilosis, Candida krusei, Candida famata, Candida rhodotorula, and Candida albicans. The antibacterial and antifungal characteristics were evaluated by measuring the diameter of growing organisms in Petri dishes treated with different concentrations of either extracts or AgNPs compared to the untreated controls. Furthermore, TEM imaging was used to investigate any ultrastructure changes in the microbes treated with crude extracts and AgNO₃.

RESULTS

The ethanolic and aqueous extracts significantly decreased the growth of E. coli, S. aureus, and B. subtilis (p < 0.001), while P. aeruginosa was not affected. Unlike crude extracts, AgNPs had more substantial antibacterial effects against all species. In addition, the mycelial growth of C. famata was reduced by the treatment of both extracts. C. krusei mycelial growth was decreased by the aqueous extract, while the growth of C. parapsilosis was affected by the ethanolic extract and AgNPs (p < 0.001). None of the treatments affected the growth of C. albicans or C. rhodotorula. TEM analysis showed cellular ultrastructure changes in the treated S. aureus and C. famata compared to the control.

CONCLUSION

The biosynthesized AgNPs and extracts of A. sieberi have a potential antimicrobial characteristic against pathogenic bacterial and fungal strains and nullified resistance behavior.

Medicinal Plants of the Flora of Kazakhstan Used in the Treatment of Skin Diseases

The skin shows the physiological condition of the body's organs and systems that prevent infections and physical damage. Throughout the ages, in folk medicine, phytotherapy was considered a primary form of treatment in all countries, including Kazakhstan, due to the abundance and availability of plant-based remedies. This paper discusses several medicinal plants that are traditionally used in the treatment of skin diseases in the Republic of Kazakhstan. The chemical composition of these plants was analyzed, with a particular focus on the biologically active basic compounds responsible for their therapeutic efficiency in treating skin ailments.

Comparative assessment of the biological activity of the green synthesized silver nanoparticles and aqueous leaf extract of Perilla frutescens (L.)

Green synthesized nanoparticles (GSNPs) display fascinating properties compared to physical and chemical synthesized ones. GSNPs are currently used in numerous applications such as food packaging, surface coating agents, environmental remediation, antimicrobial, and medicine. In the present study, the aqueous leaf extract of Perilla frutescens L. having suitable capping, reducing, and stabilizing compounds was used for green synthesis of silver nanoparticles (Pf-AgNPs). The bioreductant capacity of aqueous leaf extract of P. frutescens for Pf-AgNPs was determined by different confirmatory techniques including UV-Visible spectroscopy, XRD, FESEM, EDX, zeta potential, DLS, SERS, and FTIR analysis. The results exhibited that Pf-AgNPs had optimal size (< 61 nm), shape (spherical), and stability (- 18.1 mV). The antioxidant activity of Pf-AgNPs with both DPPH and FRAP assays was significantly higher compared to P. frutescens extract. Furthermore, Pf-AgNPs had high antimicrobial activity against Escherichia coli and Staphylococcus aureus (MIC = 0.78 mg/mL), and Candida albicans (MIC = 8 mg/mL) while the plant extract showed low antimicrobial activity against both bacterial strains and the fungus tested. Pf-AgNPs and P. frutescens extract also exhibited moderate toxicity on MCF-7 cancer cells with IC₅₀ values of 346.2 and 467.4 µg/mL, respectively. The results provide insights into using the biosynthesized Pf-AgNPs as an eco-friendly material for a wide range of biomedical applications.

Green Synthesis, Characterization, Antioxidant, Antibacterial and Enzyme Inhibition Effects of Chestnut (Castanea sativa) Honey-Mediated Silver Nanoparticles

In this study, chestnut honey-based silver nanoparticles (CH-AgNPs) were synthesized at different temperatures (30, 60 and 90 °C) and these nanoparticles were characterized by different techniques such as UV-vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The DPPH free radical scavenging assay was used to determine the antioxidant activity of the obtained nanoparticles. The inhibition effects of these nanoparticles for some clinically important enzymes such as myeloperoxidase and collagenase were investigated. In addition, the disk diffusion method (DDM), agar well diffusion (AWD), and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) techniques were used to determine the antibacterial activity of CH-AgNPs. In honey-based silver nanoparticle production processes using green synthesis, it was determined that the nanoparticle sizes decreased from 55 to 27 nm with an increase in temperature. In addition, it was determined that the rate of inhibition of myeloperoxidase (36.4% to 34.0%) and collagenase enzymes (74.2% to 68.7%) increased with a decrease in particle size. As a result of the antibacterial activity tests, it was observed that CH-AgNPs have antibacterial activity against all target pathogens including Gram-positive and Gram-negative bacteria. The obtained results show that CH-AgNPs produced using chestnut honey have the potential to be used in fields such as medicine, pharmacy and cosmetic technology.

Phytomediated Silver Nanoparticles (AgNPs) Embellish Antioxidant Defense System, Ameliorating HLB-Diseased 'Kinnow' Mandarin Plants

Citrus production is harmed worldwide by yellow dragon disease, also known as Huanglongbing (HLB), or citrus greening. As a result, it has negative effects and a significant impact on the agro-industrial sector. There is still no viable biocompatible treatment for Huanglongbing, despite enormous efforts to combat this disease and decrease its detrimental effects on citrus production. Nowadays, green-synthesized nanoparticles are gaining attention for their use in controlling various crop diseases. This research is the first scientific approach to examine the potential of phylogenic silver nanoparticles (AgNPs) to restore the health of Huanglongbing-diseased 'Kinnow' mandarin plants in a biocompatible manner. AgNPs were synthesized using Moringa oleifera as a reducing, capping, and stabilizing agent and characterized using different characterization techniques, i.e., UV-visible spectroscopy with a maximum average peak at 418 nm, scanning electron microscopy (SEM) with a size of 74 nm, and energy-dispersive spectroscopy (EDX), which confirmed the presence of silver ions along with different elements, and Fourier transform infrared spectroscopy served to confirm different functional groups of elements. Exogenously, AgNPs at various concentrations, i.e., 25, 50, 75, and 100 mgL^-1, were applied against Huanglongbing-diseased plants to evaluate the physiological, biochemical, and fruit parameters. The findings of the current study revealed that 75 mgL^-1 AgNPs were most effective in boosting the plants' physiological profiles, i.e., chl a, chl b, total chl, carotenoid content, MSI, and RWC up to 92.87%, 93.36%, 66.72%, 80.95%, 59.61%, and 79.55%, respectively; biochemical parameters, i.e., 75 mgL^-1 concentration decreased the proline content by up to 40.98%, and increased the SSC, SOD, POD, CAT, TPC, and TFC content by 74.75%, 72.86%, 93.76%, 76.41%, 73.98%, and 92.85%, respectively; and fruit parameters, i.e., 75 mgL^-1 concentration increased the average fruit weight, peel diameter, peel weight, juice weight, rag weight, juice pH, total soluble solids, and total sugarby up to 90.78%, 8.65%, 68.06%, 84.74%, 74.66%, 52.58%, 72.94%, and 69.69%, respectively. These findings enable us to develop the AgNP formulation as a potential citrus Huanglongbing disease management method.

Optimization of Major Extraction Variables to Improve Recovery of Anthocyanins from Elderberry by Response Surface Methodology

Elderberry, which is well known for its richness in anthocyanin, is attracting attention in the bioindustry as a functional material with high antioxidant capacity. The aim of this study is to optimize extraction conditions to more effectively recover anthocyanins from elderberry. In a fundamental experiment to determine the suitable solvent, various GRAS reagents, such as acetone, ethanol, ethyl acetate, hexane, and isopropyl alcohol, were used, and total phenol and anthocyanin contents were detected as 9.0 mg/g-biomass and 5.1 mg/g-biomass, respectively, only in the extraction using ethanol. Therefore, ethanol was selected as the extraction solvent, and an experimental design was performed to derive a response surface model with temperature, time, and EtOH concentration as the main variables. The optimal conditions for maximal anthocyanin recovery were determined to be 20.0 °C, 15.0 min, and 40.9% ethanol, and the total anthocyanin content was 21.0 mg/g-biomass. In addition, the total phenol and flavonoid contents were detected as 67.4 mg/g-biomass and 43.8 mg/g-biomass, respectively. The very simple and economical extraction conditions suggested in this study contributed to improving the utilization potential of anthocyanin, a useful antioxidant derived from elderberry.

Sustainable-Green Synthesis of Silver Nanoparticles Using Aqueous Hyssopus officinalis and Calendula officinalis Extracts and Their Antioxidant and Antibacterial Activities

Silver nanoparticles (AgNPs) biosynthesized using aqueous medical plant extracts as reducing and capping agents show multiple applicability for bacterial problems. The aim of this study was to expand the boundaries on AgNPs using a novel, low-toxicity, and cost-effective alternative and green approach to the biosynthesis of metallic NPs using Calendula officinalis (Calendula) and Hyssopus officinalis (Hyssopus) aqueous extracts. The formation of AgNPs was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques. The effectiveness of biosynthesized AgNPs in quenching free radicals and inhibiting the growth of Gram-positive and Gram-negative microorganisms was supported by in vitro antioxidant activity assay methods and using the Kirby-Bauer disk diffusion susceptibility test, respectively. The elucidated antimicrobial and antioxidative activities of medical plant extracts were compared with data from the engineered biosynthetic AgNPs. The antimicrobial effect of engineered AgNPs against selected test cultures was found to be substantially stronger than for plant extracts used for their synthesis. The analysis of AgNPs by TEM revealed the presence of spherical-shaped nano-objects. The size distribution of AgNPs was found to be plant-type-dependent. The smaller AgNPs were obtained with Hyssopus extract (with a size range of 16.8 ± 5.8 nm compared to 35.7 ± 4.8 nm from Calendula AgNPs). The AgNPs' presumably inherited biological functions of Hyssopus and Calendula medical plants can provide a platform to combat pathogenic bacteria in the era of multi-drug resistance.

Hydrothermal assisted biogenic synthesis of silver nanoparticles: A potential study on virulent candida isolates from COVID-19 patients

Till now the exact mechanism and effect of biogenic silver nanoparticles on fungus is an indefinable question. To focus on this issue, the first time we prepared hydrothermal assisted thyme coated silver nanoparticles (T/AgNPs) and their toxic effect on Candida isolates were determined. The role of thyme (Thymus Vulgaris) in the reduction of silver ions and stabilization of T/AgNPs was estimated by Fourier transforms infrared spectroscopy, structure and size of present silver nanoparticles were detected via atomic force microscopy as well as high-resolution transmission electron microscopy. The biological activity of T/AgNPs was observed against Candida isolates from COVID-19 Patients. Testing of virulence of Candida species using Multiplex PCR. T/AgNPs proved highly effective against Candida albicans, Candida kruzei, Candida glabrata and MIC values ranging from 156.25 to 1,250 μg/mL and MFC values ranging from 312.5 to 5,000 μg/mL. The structural and morphological modifications due to T/AgNPs on Candida albicans were detected by TEM. It was highly observed that when Candida albicans cells were subjected to 50 and 100 μg/mL T/AgNPs, a remarkable change in the cell wall and cell membrane was observed.

Light-emitting diode (LED)-directed green synthesis of silver nanoparticles and evaluation of their multifaceted clinical and biological activities

The trend of using plant extracts for the synthesis of nanoparticles has increased in recent years due to environmental safety, low cost, simplicity and sustainability of the green route. Moreover, the morphology of NPs can be fine-tuned by applying abiotic factors such as LEDs, which enhance the bio-reduction of the precursor salt and excite phytochemicals during their green synthesis. Considering this, in present study, the green synthesis of AgNPs was carried out using Dalbergia sissoo leaf extract under the illumination of red, green, blue, yellow and white LEDs. The phytochemical profile of the leaf extract in terms of total phenolic and flavonoid content was responsible for the effective synthesis of AgNPs, where alcohols and phenols were mainly involved in the capping and bio-reduction of the NPs. Moreover, the XRD data showed the face center cubic crystalline nature of the AgNPs with the interesting finding that the LEDs helped to reduce the size of the AgNPs significantly. Among the samples, Y-DS-AgNPs (34.63 nm) were the smallest in size, with the control having a size of 87.35 nm. The LEDs not only reduced the size of the AgNPs but also resulted in the synthesis of non-agglomerated AgNPs with different shapes including spherical, triangular, and hexagonal compared to the mixed-shape control AgNPs, as shown by the SEM analysis. These LED-directed AgNPs showed extraordinary therapeutic potential especially B-DS-AgNPs, which exhibited the highest anti-oxidant, anti-glycation and anti-bacterial activities. Alternatively, Y-DS-AgNPs were the most cytotoxic towards HepG2 cells, inducing intracellular ROS/RNS production, accompanied by a disruption in the mitochondrial membrane potential, caspase-3 gene activation and induction of caspase-3/7 activity. Lastly, AgNPs showed mild toxicity towards brine shrimp and moderately hemolyzed hRBCs, showing their biosafe nature. Here, we conclude that external factors such as LEDs are effective in controlling the morphology of AgNPs, which further enhanced their therapeutic efficacy.

Antimicrobial Activities against Opportunistic Pathogenic Bacteria Using Green Synthesized Silver Nanoparticles in Plant and Lichen Enzyme-Assisted Extracts

Enzyme-assisted extraction is a valuable tool for mild and environmentally-friendly extraction conditions to release bioactive compounds and sugars, essential for silver nanoparticle (AgNP) green synthesis as capping and reducing agents. In this research, plant and fungal kingdoms were selected to obtain the enzyme-assisted extracts, using green synthesized AgNPs. For the synthesis, pseudo-cereal Fagopyrum esculentum (F. esculentum) and lichen Certaria islandica (C. islandica) extracts were used as environmentally-friendly agents under heating in an aqueous solution. Raw and enzyme-assisted extracts of AgNPs were characterized by physicochemical, phytochemical, and morphological characteristics through scanning and transmission electron microscopy (SEM and TEM), as well as Fourier transform infrared spectroscopy (FTIR). The synthesized nanoparticles were spherical in shape and well dispersed, with average sizes ranging from 10 to 50 nm. This study determined the total phenolic content (TPC) and in vitro antioxidant activity in both materials by applying standard methods. The results showed that TPC, ABTS^•+, FRAP, and DPPH^• radical scavenging activities varied greatly in samples. The AgNPs derived from enzymatic hydrolyzed aqueous extracts C. islandica and F. esculentum exhibited higher antibacterial activity against the tested bacterial pathogens than their respective crude extracts. Results indicate that the extracts’ biomolecules covering the AgNPs may enhance the biological activity of silver nanoparticles and enzyme assistance as a sustainable additive to technological processes to achieve higher yields and necessary media components.

Aralia cordata Thunb. as a Source of Bioactive Compounds: Phytochemical Composition and Antioxidant Activity

Plant primary and secondary metabolites are a significant source for many applications, including extractions of functional components, green synthesis development, and producing higher-added value products. However, in the variety of botanicals, Aralia cordata Thunb. plant is getting attention for its similarity to ginseng. This study comprehensively examines the biochemical and phytochemical profiles of different A. cordata morphological parts: root, stem, leaf, inflorescence, berry, and seed. Additionally, the establishment of total phenolic content and quantitative analysis of powerful antioxidants such as chlorophyll, carotenoids (zeaxanthin, lutein, and β-carotene), proanthocyanidins, and anthocyanins content were evaluated. The results indicated that A. cordata stem and berries are an excellent source of anthocyanins in the range from 18.27 to 78.54 mg/100 g DW. Meanwhile, the antioxidant activity was evaluated using three different methods based on the capacity to scavenge: DPPH^• scavenging capacity, ABTS^•+ radical cation assay, and ferric reducing antioxidant power (FRAP) and ranged from 27 to 168 µmol TE/g DW, 8 to 117 µmol TE/g DW, and 18 to 157 µmol TE/g DW, respectively. This study proposes a novel competitive plant for many health-promoting applications in the nutraceutical, pharmaceutical, material, and food industries.

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.

Fabrication of anti-bacterial cotton bandage using biologically synthesized nanoparticles for medical applications

Recently the use of plant-derived extracts for the green synthesis of nanoparticles has drawn considerable attention. In the present study silver and copper nanoparticles were synthesized using extracts of Andrographis paniculata which is found to possess various pharmacological properties. The synthesized nanoparticles were characterized using UV spectroscopy, SEM with EDS, XRD, TEM and DLS. Furthermore, an attempt is made to impregnate these nanoparticles onto cotton bandages. The structure and morphology of silver nanoparticles impregnated onto the cotton bandages were confirmed by SEM. The anti-bacterial activity of cotton bandages loaded with silver and copper nanoparticles was tested against Escherichia coli, Bacillus cereus, and Staphylococcus aureus using a modified disc diffusion assay. The results indicate that the cotton bandages biofabricated with nanoparticles exhibited anti-bacterial activity in terms of zone of inhibition of growth of tested bacteria suggesting their usage as medical textiles in various biomedical applications for the prevention of infections. Hence, the nanoparticles impregnated cotton fibers can be applied for the development of masks, aprons, etc. to protect against bacterial penetration and as well to counteract the present situation of the world.

Eucalyptus globulus and Salvia officinalis Extracts Mediated Green Synthesis of Silver Nanoparticles and Their Application as an Antioxidant and Antimicrobial Agent

Silver nanoparticles (AgNPs) biosynthesized using plant extracts as reducing and capping agents show multiple possibilities for solving various biological problems. The aim of this study was to expand the boundaries of AgNPs using a novel low toxicity and production cost phytochemical method for the biosynthesis of nanoparticles from Eucalyptus globulus and Salvia officinalis aqueous leaf extracts. Biosynthesized AgNPs were characterized by various methods (ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared (FTIR) spectroscopy with horizontal attenuated total reflectance (HART), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS)). The determined antioxidative and antimicrobial activity of plant extracts was compared with the activity of the AgNPs. The UV-vis spectral analysis demonstrated the absorption peaks at 408 and 438 nm, which confirmed the synthesis of stable AgNPs from E. globulus and S. officinalis, respectively. FTIR-HART results suggested strong capping of phytochemicals on AgNPs. TEM results show mainly spherical-shaped AgNPs, whose size distribution depends on the plant leaf extract type; the smaller AgNPs were obtained with E. globulus extract (with size range of 17.5 ± 5.89 nm compared to 34.3 ± 7.76 nm from S. officinalis AgNPs). The in vitro antioxidant activity evaluated by radical scavenging assays and the reduction activity method clearly demonstrated that both the plant extracts and AgNPs showed prominent antioxidant properties. In addition, AgNPs show much stronger antimicrobial activity against broad spectrum of Gram-negative and Gram-positive bacteria strains than the plant extracts used for their synthesis.

Enzymes-Assisted Extraction of Plants for Sustainable and Functional Applications

The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers' demands while searching for 'clean label' food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes' ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes' incorporation into processes has limitations and is regulated by national and international levels.

Berries and Leaves of Actinidia kolomikta (Rupr. & Maxim.) Maxim.: A Source of Phenolic Compounds

Berries of Actinidia kolomikta (A. kolomikta) are known for high ascorbic acid content, but the diversity of phenolic compounds has been little studied. The present research aimed to investigate phenolic compounds and antioxidant activity in berries and leaves of twelve A. kolomikta cultivars. The UHPLC-ESI-MS/MS technique was used to determine differences among cultivars in the quantitative composition of individual phenolic compounds. Antioxidant activity was determined by DPPH• free radical scavenging and CUPRAC methods. In the present study, 13 phenolic compounds were detected in berries, whereas leaves contained 17 phenolic compounds. Flavonols were the primary class found in both berries and leaves; other identified phenolic compounds were flavan-3-ols, flavones and, phenolic acids; and dihydrochalcone phloridzin was identified in the leaves. The amount and variety of phenolic compounds in berries and leaves and antioxidant activity were found to be cultivar-dependent. The highest total content of phenolic compounds was found in the leaves of the cultivar ‘Aromatnaja’ and in the berries of the cultivar ‘VIR-2’. Results of this study have confirmed that berries and leaves of A. kolomikta could be a valuable raw material for both food and pharmaceutical industries.

Marine Macroalgae Display Bioreductant Efficacy for Fabricating Metallic Nanoparticles: Intra/Extracellular Mechanism and Potential Biomedical Applications

The application of hazardous chemicals during nanoparticle (NP) synthesis has raised alarming concerns pertaining to their biocompatibility and equally to the environmental harmlessness. In the recent decade, nanotechnological research has made a gigantic shift in order to include the natural resources to produce biogenic NPs. Within this approach, researchers have utilized marine resources such as macroalgae and microalgae, land plants, bacteria, fungi, yeast, actinomycetes, and viruses to synthesize NPs. Marine macroalgae (brown, red, and green) are rich in polysaccharides including alginates, fucose-containing sulfated polysaccharides (FCSPs), galactans, agars or carrageenans, semicrystalline cellulose, ulvans, and hemicelluloses. Phytochemicals are abundant in phenols, tannins, alkaloids, terpenoids, and vitamins. However, microorganisms have an abundance of active compounds ranging from sugar molecules, enzymes, canonical membrane proteins, reductase enzymes (NADH and NADPH), membrane proteins to many more. The prime reason for using the aforesaid entities in the metallic NPs synthesis is based on their intrinsic properties to act as bioreductants, having the capability to reduce and cap the metal ions into stabilized NPs. Several green NPs have been verified for their biocompatibility in human cells. Bioactive constituents from the above resources have been found on the green metallic NPs, which has demonstrated their efficacies as prospective antibiotics and anti-cancer agents against a range of human pathogens and cancer cells. Moreover, these NPs can be characterized for the size, shapes, functional groups, surface properties, porosity, hydrodynamic stability, and surface charge using different characterization techniques. The novelty and originality of this review is that we provide recent research compilations on green synthesis of NPs by marine macroalgae and other biological sources (plant, bacteria, fungi, actinomycetes, yeast, and virus). Besides, we elaborated on the detailed intra- and extracellular mechanisms of NPs synthesis by marine macroalgae. The application of green NPs as anti-bacterial, anti-cancer, and popular methods of NPs characterization techniques has also been critically reviewed.