Green synthesis of silver nanoparticles using seed extract of Calendula officinalis in liquid phase

A Facile and Green Approach for the Preparation of Silver Nanoparticles on Graphene Oxide with Favorable Antibacterial Activity

Herein, we introduce a simple precipitation method for preparing graphene oxide-silver nanoparticle (GO/AgNP) composites, utilizing Calendula officinalis (C. officinalis) seed extract as both a reducing and stabilizing agent. Our research combines the sustainable preparation of graphene oxide (GO) with the green synthesis of silver nanoparticles (AgNPs), aiming to explore the potential of the obtained composite as a novel antibacterial material. To establish a benchmark, the synthesis was also performed using sodium citrate, a conventional reducing agent. The resultant GO/AgNP composites were characterized through several analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), infrared (IR) spectroscopy, and ultraviolet-visible (UV-vis) spectroscopy, confirming the successful functionalization of GO with AgNPs. The antibacterial effectiveness of the composites was systematically assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with nanoparticle concentrations spanning from 0 to 250 µg/mL, utilizing mostly disk diffusion and colony-forming unit (CFU) count assays. The AgNPs were characterized by a size range of 15-50 nm. Notably, the GO/AgNP composite prepared using C. officinalis seed extract demonstrated superior antibacterial activity at all tested concentrations, outperforming both pure GO and the GO/AgNP composite prepared with sodium citrate. The most pronounced antibacterial effect was observed at a concentration of 32.0 µg/mL. Therefore, this innovative synthesis approach may offer a valuable contribution to the development of new therapeutic agents to combat bacterial infections, suggesting further exploration into antibacterial coatings or potential drug development.

Green Synthesis of Silver Nanoparticle Using Black Mulberry and Characterization, Phytochemical, and Bioactivity

Synthesis of silver nanoparticles (AgNPs) using plant extracts has been proposed as a more advantageous and environmentally friendly alternative compared to existing physical/chemical methods. In this study, AgNPs were synthesized from silver nitrate using black mulberry (BM) extract. The biosynthesized AgNPs were characterized through an UV-visible spectrometer, X-ray diffraction, and transmission electron microscopy. Additionally, BM-AgNPs were subjected to antioxidant, antibacterial, anti-inflammatory, and anticancer activities. AgNPs biosynthesized from BM extract were dark brown in color and showed a strong peak at 437 nm, confirming that AgNPs were successfully synthesized. The size of AgNPs was 170.17 ± 12.65 nm, the polydispersity index was 0.281 ± 0.07, and the zeta potential value was -56.6 ± 0.56 mV, indicating that the particles were stable. The higher total phenol, flavonoid, and anthocyanin content of BM-AgNPs compared to BM extract indicates that the particles contain multiple active substances due to the formation of AgNPs. The DPPH and ABTS assays showed decreased IC50 values compared to BM extract, demonstrating improved antioxidant activity. AgNPs inhibited the growth of S. aureus and E. coli at 600 μg/mL, with minimum bactericidal concentrations determined to be 1000 and 1200 μg/mL, respectively. The anti-inflammatory activity was 64.28% at a BM-AgNPs concentration of 250 μg/mL. As the concentration increased, the difference from the standard decreased, indicating the inhibitory effect of AgNPs on bovine serum albumin denaturation. The viability of MCF-7 cells treated with BM-AgNPs was found to be significantly lower than that of cells treated with BM extract. The IC50 value of BM-AgNPs was determined to be 96.9 μg/mL. This study showed that BM-AgNPs have the potential to be used in the pharmaceutical industry as antioxidant, antibacterial, anti-inflammatory, and anticancer agents.

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

MAIN CONCLUSION

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

Lipid-Based Delivery Systems for Flavonoids and Flavonolignans: Liposomes, Nanoemulsions, and Solid Lipid Nanoparticles

Herbal chemicals with a long history in medicine have attracted a lot of attention. Flavonolignans and flavonoids are considered as two classes of the above-mentioned compounds with different functional groups which exhibit several therapeutic capabilities such as antimicrobial, anti-inflammatory, antioxidant, antidiabetic, and anticancer activities. Based on the studies, high hydrophobic properties of the aforementioned compounds limit their bioavailability inside the human body and restrict their wide application. Nanoscale formulations such as solid lipid nanoparticles, liposomes, and other types of lipid-based delivery systems have been introduced to overcome the above-mentioned challenges. This approach allows the aforementioned hydrophobic therapeutic compounds to be encapsulated between hydrophobic structures, resulting in improving their bioavailability. The above-mentioned enhanced delivery system improves delivery to the targeted sites and reduces the daily required dosage. Lowering the required daily dose improves the performance of the drug by diminishing its side effects on non-targeted tissues. The present study aims to highlight the recent improvements in implementing lipid-based nanocarriers to deliver flavonolignans and flavonoids.

Traditionally used medicinal plants mediate the biosynthesis of silver nanoparticles: methodological, larvicidal, and ecotoxicological approach

It has been shown that vegetal species constitute an alternative natural source for the biosynthesis of new nanomaterials. Thus, aiming to expand knowledge about the potential use of plants in the fabrication of metallic nanomaterials, we aimed to synthesize silver nanoparticles (AgNPs) from phyto-formulation (PF) of ten commonly used medicinal plants. Our results demonstrate the formation of spherical, stable, polycrystalline AgNPs with a diameter of 8.42 nm to 18.40 nm, whose biosynthesis confirmation was performed via UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM)-energy dispersive X-ray spectroscopy (EDS) mapping, high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and zeta potential studies. Furthermore, we demonstrated that the biosynthesized AgNPs showed larvicidal activity against Aedes aegypti and Anopheles stephensi larvae, with the histopathology findings from the fourth instar larval stage validating such larvicidal toxicity. The histological examinations showed severe degradation of the larvae's hindgut, epithelial cells, midgut, and cortical area. However, the PF extract and the biosynthesized AgNPs showed high ecotoxicity in Danio rerio larvae exposed to different concentrations. The treatments induced changes in hatchability percentage, animal growth, and heartbeat. Therefore, despite supporting the potential of PF (from ten plant species) as a raw material source for AgNPs biosynthesis, our study also sheds light on its ecotoxicological potential, suggesting that more comprehensive assessments of the ecotoxicity of biosynthesized would be performed before its application in different sectors.

Green Synthesis of Bioinspired Nanoparticles Mediated from Plant Extracts of Asteraceae Family for Potential Biological Applications

The Asteraceae family is one of the largest families in the plant kingdom with many of them extensively used for significant traditional and medicinal values. Being a rich source of various phytochemicals, they have found numerous applications in various biological fields and have been extensively used for therapeutic purposes. Owing to its potential phytochemicals present and biological activity, these plants have found their way into pharmaceutical industry as well as in various aspects of nanotechnology such as green synthesis of metal oxide nanoparticles. The nanoparticles developed from the plants of Asteraceae family are highly stable, less expensive, non-toxic, and eco-friendly. Synthesized Asteraceae-mediated nanoparticles have extensive applications in antibacterial, antifungal, antioxidant, anticancer, antidiabetic, and photocatalytic degradation activities. This current review provides an opportunity to understand the recent trend to design and develop strategies for advanced nanoparticles through green synthesis. Here, the review discussed about the plant parts, extraction methods, synthesis, solvents utilized, phytochemicals involved optimization conditions, characterization techniques, and toxicity of nanoparticles using species of Asteraceae and their potential applications for human welfare. Constraints and future prospects for green synthesis of nanoparticles from members of the Asteraceae family are summarized.

Polyacrylamide Hydrogel Containing Calendula Extract as a Wound Healing Bandage: In Vivo Test

Hydrogel is a biomaterial widely used in several areas of industry due to its great biocompatibility and adaptability to biological tissues. In Brazil, the Calendula plant is approved by the Ministry of Health as a medicinal herb. It was chosen to be incorporated in the hydrogel formulation because of its anti-inflammatory, antiseptic and healing effects. This study synthesized polyacrylamide hydrogel containing calendula extract and evaluated its efficiency as a bandage for wound healing. The hydrogels were prepared using free radical polymerization and characterized by Scanning Electron Microscopy, swelling analysis and mechanical properties by texturometer. The morphology of the matrices showed large pores and foliaceous structure. In vivo testing, as well as the evaluation of acute dermal toxicity, was conducted using male Wistar rats. The tests indicated efficient collagen fiber production, improved skin repair and no signs of dermal toxicity. Thus, the hydrogel presents compatible properties for the controlled release of calendula extract used as a bandage to promote cicatrization.

Ecofriendly phytofabrication of silver nanoparticles using aqueous extract of Cuphea carthagenensis and their antioxidant potential and antibacterial activity against clinically important human pathogens

The green synthesis of nanoparticles (NPs) is the safest, ecofriendly, cost-effective, and non-hazardous approach of nanotechnology. In the current study, we described the green synthesis of silver nanoparticles (AgNPs) using Cuphea carthagenensis aqueous leaf extract as a reducing, capping, and stabilizing agent. The study aims at the synthesis, characterization, optimization, and determination of the antibacterial activity of Cc-AgNPs against clinically important human pathogens. Coating of cotton fabrics with Cc-AgNPs and their efficacy against skin infection causing organisms was also evaluated. Furthermore, antioxidant activity, growth assay and time kill assay of Cc-AgNPs were also performed in the study. The biosynthesized Cc-AgNPs were characterized by UV-visible spectrometry, energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR). The spectroscopic and microscopic analysis demonstrated biosynthesis of face-centered cubic (fcc) crystalline spherical Cc-AgNPs with an average particle size of 10.65 ± 0.1 nm. Optimized peak synthesis of Cc-AgNPs was reported at pH7, 55 °C, 4 mM silver nitrate, and 5:45 (plant extract: silver nitrate). Cc-AgNPs exhibited potent antioxidant effect and antibacterial activity against both Gram-positive and Gram-negative bacteria. The lowest MIC (15 μg/ml) and MBC (25 μg/ml) values were reported against S. typhimurium. The Cc-AgNPs coated fabrics demonstrated potent antibacterial activity against tested strains. This application could be helpful in wound healing management. Furthermore, the hemolytic analysis demonstrated that Cc-AgNPs exhibit non-toxic nature against Red Blood Cells (RBCs) at the tested concentrations. In conclusion, the investigation demonstrated a fast, stable, and eco-friendly approach to the biosynthesis of Cc-AgNPs along with their antibacterial and antioxidant properties.

Plant-mediated gold and silver nanoparticles as detectors of heavy metal contamination

Heavy metals are dumped into the environment as a result of human activities, posing a serious threat to ecology and human health. Surface water, potable drinking water, potable groundwater, and majority of wastewater include their traces, due to which, their detection by nanoparticles has received a lot of attention in recent years. Although microorganisms are utilised for green nanoparticle production, plant materials have recently been explored because they are more environmentally friendly, easier to scale up, and require fewer specific growth conditions. The production and attributes of nanoparticles synthesized by plant mediation could be enhanced through design of experiments approach, extending their feasibility in the detection of heavy metals in polluted environmental samples. A concise review on green synthesis of silver and gold nanoparticles utilizing plant phytochemicals, its mechanism of synthesis along with significance of design of experiments for enhancement, and their use as heavy metal contamination detectors is presented in the current study.

Multifarious global flora fabricated phytosynthesis of silver nanoparticles: a green nanoweapon for antiviral approach including SARS-CoV-2

The progressive research into the nanoscale level upgrades the higher end modernized evolution with every field of science, engineering, and technology. Silver nanoparticles and their broader range of application from nanoelectronics to nano-drug delivery systems drive the futuristic direction of nanoengineering and technology in contemporary days. In this review, the green synthesis of silver nanoparticles is the cornerstone of interest over physical and chemical methods owing to its remarkable biocompatibility and idiosyncratic property engineering. The abundant primary and secondary plant metabolites collectively as multifarious phytochemicals which are more peculiar in the composition from root hair to aerial apex through various interspecies and intraspecies, capable of reduction, and capping with the synthesis of silver nanoparticles. Furthermore, the process by which intracellular, extracellular biological macromolecules of the microbiota reduce with the synthesis of silver nanoparticles from the precursor molecule is also discussed. Viruses are one of the predominant infectious agents that gets faster resistance to the antiviral therapies of traditional generations of medicine. We discuss the various stages of virus targeting of cells and viral target through drugs. Antiviral potential of silver nanoparticles against different classes and families of the past and their considerable candidate for up-to-the-minute need of complete addressing of the fulminant and opportunistic global pandemic of this millennium SARS-CoV2, illustrated through recent silver-based formulations under development and approval for countering the pandemic situation.

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Polyphenolic extracts from pomegranate and watermelon wastes as substrate to fabricate sustainable silver nanoparticles with larvicidal effect against Spodoptera littoralis

The agricultural wastes adversely affect the environment; however, they are rich in polyphenols; therefore, this study aimed to employ polyphenol-enriched waste extracts for silver nanoparticles synthesis, and study the larvicidal activity of silver nanoparticles fabricated by pomegranate and watermelon peels extracts (PPAgNPs and WPAgNPs) against all larval instars of Spodoptera littoralis. The polyphenol profile of pomegranate and watermelon peel extracts (PP and WP) and silver nanoparticles was detected by HPLC. The antioxidant activity was estimated by DPPH, and FARP assays and the antimicrobial activity was evaluated by disc assay. The Larvicidal activity of AgNPs against Egyptian leaf worm was performed by dipping technique. The obtained AgNPs were spherical with size ranged 15-85 nm and capped with proteins and polyphenols. The phenolic compounds in silver nanoparticles increased about extracts; therefore, they have the best performance in antioxidant/reducing activity, and inhibit the growth of tested bacteria and yeast. The PPAgNPs were the most effective against the first instar larvae instar (LC50 = 68.32 µg/ml), followed by pomegranate extract with (LC50 = 2852 µg/ml). The results indicated that obvious increase in polyphenols content in silver nanoparticles enhance their larvicidal effect and increasing mortality of 1st larval of S. littoralis Egyptian leafworms causing additive effect and synergism. We recommend recycling phenolic enriched agricultural wastes in producing green silver nanoprticles to control cotton leafworm that causes economic loses to crops.

Rhodiola rosea Rhizome Extract-Mediated Green Synthesis of Silver Nanoparticles and Evaluation of Their Potential Antioxidant and Catalytic Reduction Activities

The silver nanoparticles (AgNPs) using the rhizome extract of Rhodiola rosea have been reported. However, their antioxidant activity and whether the biogenic AgNPs could be used to catalyze the reduction of hazardous dye or used as fluorescence enhancers are unknown. This study focused on the facile green synthesis of silver nanoparticles using the rhizome aqueous extract of R. rosea (G-AgNPs). We then studied their antioxidant activity and catalytic degradation of hazardous dye Direct Orange 26 (DO26) and Direct Blue 15 (DB15). Their effects on fluorescein's fluorescent properties were also evaluated. The chemical AgNPs (C-AgNPs) were synthesized by reducing solid sodium borohydride (NaBH₄), and its above activities were compared with those of G-AgNPs. The formation of G-AgNPs was confirmed by the appearance of brownish-gray color and the surface plasmon resonance (SPR) peak at 437 nm. The biogenic AgNPs were approximately 10 nm in size with a regular spherical shape identified from transmission electron microscopy (TEM) analysis. G-AgNPs exhibited significantly improved 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity than butylated hydroxytoluene (BHT) and C-AgNPs (p < 0.05). The biogenic G-AgNPs were also found to function as an effective green catalyst in reducing DO26 and DB15 by NaBH₄, which is superior to C-AgNPs. Furthermore, G-AgNPs showed better fluorescence enhancement activity than C-AgNPs, and the concentration required was lower. When the concentration of the G-AgNP solution was 64 nmol/L, the fluorescence intensity reached the maximum of 5460, with the fluorescence enhancement efficiency of 3.39, and the fluorescence activity was stable within 48 h. This study shows the efficacy of biogenic AgNPs in catalyzing the reduction of hazardous dye DO26 and DB15. Biogenic AgNPs could also be used as fluorescence enhancers in low concentrations.

Green Synthesis of Metallic Nanoparticles: Applications and Limitations

The past decade has witnessed a phenomenal rise in nanotechnology research due to its broad range of applications in diverse fields including food safety, transportation, sustainable energy, environmental science, catalysis, and medicine. The distinctive properties of nanomaterials (nano-sized particles in the range of 1 to 100 nm) make them uniquely suitable for such wide range of functions. The nanoparticles when manufactured using green synthesis methods are especially desirable being devoid of harsh operating conditions (high temperature and pressure), hazardous chemicals, or addition of external stabilizing or capping agents. Numerous plants and microorganisms are being experimented upon for an eco–friendly, cost–effective, and biologically safe process optimization. This review provides a comprehensive overview on the green synthesis of metallic NPs using plants and microorganisms, factors affecting the synthesis, and characterization of synthesized NPs. The potential applications of metal NPs in various sectors have also been highlighted along with the major challenges involved with respect to toxicity and translational research.

Effect of Plant Extracts on the Characteristics of Silver Nanoparticles for Topical Application

Silver nanoparticles (AgNPs) were synthesized using hydroalcoholic extracts of dittany (Origanum dictamnus), sage (Salvia officinalis), sea buckthorn (Elaeagnus rhamnoides, syn. Hippophae rhamnoides), and calendula (Calendula officinalis) as reducing agents. AgNPs synthesized using NaBH₄ and citric acid were used as control. The impact of the origin of the extract and preparation conditions (light, temperature, reaction time) on the properties of the synthesized AgNPs was investigated. The structure, morphology, composition, physicochemical characteristics, and colloidal stability were characterized using dynamic laser scattering (DLS), ultraviolet-visible spectrophotometry (UV–/Vis), XRD, X-ray fluorescence (XRF), TEM, and FTΙR. The reduction of total phenolic and flavonoid content of the extracts after the reaction of AgNPs synthesis was also determined. Low IC50 values for all types of AgNPs revealed good antioxidant activity, attributable to the phenolic and flavonoid content of their surface. The results suggest that plant extract selection is important to the green synthesis of AgNPs because it affects the kinetics of their synthesis as well as their morphology, physicochemical characteristics, and colloidal stability. In vitro permeation studies on porcine skin revealed that AgNPs remained at the upper layers of stratum corneum and did not penetrate the skin barrier after 4 h of cutaneous application suggesting the safety of their application on intact skin for a relatively short time.

Review on Green Synthesis of Silver Nanoparticles through Plants

Nature has the potential to reduce metal salts to their relative nanoparticles. Traditionally, physical and chemical methods were used for the synthesis of nanoparticles but due to the use of toxic chemicals, non-ecofriendly methods and other harmful effects, green chemistry approaches are now employed for synthesizing nanoparticles which are basically the most cost effective, ecofriendly and non-hazardous methods. In this review, we aimed to evaluate and study the details of various mechanisms used for green synthesis of silver nanoparticles from plants, their size, shape and potential applications. A total of 150 articles comprising both research and review articles from 2009 to 2019 were selected and studied in detail to get in-depth knowledge about the synthesis of silver nanoparticles specifically through green chemistry approaches. Silver ions and their salts are well known for their antimicrobial properties and have been used in various medical and non-medical applications since the emergence of human civilization. Miscellaneous attempts have been made to synthesize nanoparticles using plants and such nanoparticles are more efficient and beneficial in terms of their antibacterial, antifungal, antioxidant, anti-biofilm and cytotoxic activities than nanoparticles synthesized through physical and chemical processes. Silver nanoparticles have been studied as an important research area due to their specific and tunable properties and their application in the field of biomedicine such as tissue and tumor imaging and drug delivery. These nanoparticles can be further investigated to find out their antimicrobial potential in cell lines and animal models.

Characterization and the evaluation of antimicrobial activities of silver nanoparticles biosynthesized from Carya illinoinensis leaf extract

A green, direct and cost-effective fabrication method is proposed for Eco-environmentally silver nanoparticles (AgNPs) through leaf extraction of Carya illinoinensis from Iran. Formation of Ag NPs was confirmed through different characterization techniques such as UV–Vis Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). UV-Visible spectrophotometer showed absorbance peak at 440 nm due to the Surface Plasmon Resonance (SPR). Based on XRD results and SEM and TEM analysis, AgNPs were crystalline with face-centered cubic geometry and in different sizes ranged 12–30 nm. Furthermore, FTIR Spectroscopy was utilized to recognize the specific functional groups responsible for reducing ion silver to silver nanoparticles and the capping agents available in the leaf extract. In addition, the antibacterial effect of Eco-friendly synthesized nanoparticles and also leaf extract, were evaluated on four pathogens by implementing minimum inhibitory concentration test (MIC) and agar diffusion assay. The MIC results exhibits more inhibiting activity against gram-negative microorganisms (Escherichia coli and Pseudomonas aeruginosa) rather than gram-positive microorganisms (Staphylococcus aureus and Listeria monocytogenes). Compared to leaf extract, nanoparticles have better antimicrobial activity against both Gram-positive and Gram-negative bacteria.

Facile coconut inflorescence sap mediated synthesis of silver nanoparticles and its diverse antimicrobial and cytotoxic properties

Green synthesis of nanoparticles (NPs) involves the use of diverse extracts of biological origin as substrates to synthesize NPs and can overcome the hazards associated with chemical methods. Coconut inflorescence sap, which is unfermented phloem sap obtained by tapping of coconut inflorescence, is a rich source of sugars and secondary metabolites. In this study, coconut inflorescence sap was used to synthesize silver NPs (AgNPs). We have initially undertaken metabolomic profiling of coconut inflorescence sap from West Coast Tall cultivar to delineate its individual components. It was found to comprise of 64% secondary metabolites, 9% sugars, 12% lipids/fats and 9% peptides in positive mode, whereas in the negative mode, it was 33, 20, 9 and 11%, respectively. The concentration of silver nitrate, inflorescence sap and incubation temperature for the synthesis of AgNPs were optimized. Incubating the reaction mixture at 40 °C was found to enhance AgNP synthesis. The AgNPs synthesized were characterized using UV-visible (UV-Vis) spectrophotometry, X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). The particles were crystalline in nature and the bulk of the particles were spherical with smooth (thin) shell and poly-dispersed with a diameter ranging from 10 nm to 30 nm. Antimicrobial property of AgNPs was tested in tissue culture of arecanut (Areca catechu L.) where bacterial contamination (Bacillus pumilus) was a frequent occurrence. A significant reduction in the contamination was observed when plantlets were treated with aqueous solutions of AgNPs. Notably, treatment with AgNPs did not affect the growth and development of the arecanut plantlets. Antimicrobial properties of AgNPs synthesized from inflorescence sap were also evaluated in human pathogenic bacteria viz., Escherichia coli ATCC 25922; Salmonella Typhimurium ATCC 14028 and Vibrio parahaemolyticus AQ4037. The antibacterial action was confirmed by determining the production of reactive oxygen species (ROS) and protein leakage studies. Cytotoxicity of AgNPs was quantified in HeLa cells. The viability (%) of HeLa cells declined significantly at 10 mg L^-1 concentration of AgNP and complete mortality was observed at a concentration of 60 mg L^-1. The study concludes that unfermented inflorescence sap, with above neutral pH, serves as an excellent reducing agent to synthesize AgNPs from Ag+.

Green Synthesis of Silver Nanoparticles Using Bilberry and Red Currant Waste Extracts

The production of silver nanoparticles (Ag-NPs) from bilberry waste (BW) and red currant waste (RCW) extracts was studied. Red fruit extracts were obtained by treating BW and RCW with aqueous ethanol (50% v/v) at 40 °C. The formation of nanoparticles was monitored spectrophotometrically by measuring the intensity of the surface plasmon resonance band (SPR) of silver. The effects of temperature (20–60 °C) and pH (8–12) on the reaction kinetics and on the properties of Ag-NPs were investigated. Characterization by XRD and dynamic light scattering (DLS) techniques showed that Ag-NPs were highly crystalline, with a face-centered cubic structure and a hydrodynamic diameter of 25–65 nm. The zeta potential was in the range of −35.6 to −20.5 mV. Nanoparticles obtained from BW were slightly smaller and more stable than those from RCW. A kinetic analysis by the initial-rate method showed that there was an optimum pH, around 11, for the production of Ag-NPs. Overall, the results obtained suggest that BW and RCW can be advantageously used as a source of reducing and stabilizing agents for the green synthesis of Ag-NPs.

A Systematic Review on Prevention and Treatment of Nipple Pain and Fissure: Are They Curable?

Averagely 80% to 90% of breastfeeding women experience the nipple pain and fissures. The important factor for successful breastfeeding is to treat this problem. This study has done as a review with the aim of analysis of the clinical trials in the field of the prevention and treatment of the nipple fissures and pain due to the importance of breastfeeding. For this purpose, the key words of sore, nipples, fissure, trauma, wound, prevention, treatment, therapeutics, therapy, clinical trial, breastfeeding and their Persian synonyms and all of their possible combinations were searched in the national databases: SID and Iran Medex and Magiran, and in the international databases: PubMed, Scopus, Medline, Science direct by May 2017. The Jadad criterion was used to assess the quality of the articles and the articles with a score of 3 or more were included in this study. Finally, 48 clinical trials were reviewed that 17 of them (sample size 1801) scored 3 or more based on the Jadad criterion. Seven articles were also in the non- drug treatment group (sample size 491) and 2 articles in the drug treatment group (sample size 337) and 8 articles in the herbal treatment group (sample size 973).The results show that menthol and warm water compress as well as teaching the correct breastfeeding methods are effective treatments to prevent and treat the nipple pain and fissures. Moreover, applying the herbal medicine for prevention and treatment of the issues raised from breastfeeding may have beneficial such as Aloe vera, Portulaca olearacea. However, more studies with a great methodology are necessary to obtain more accurate evidence.

Green synthesis of silver nanoparticles with the Arial part of Dorema ammoniacum D. extract by antimicrobial analysis

Silver nanoparticles (SNPs) were synthesised by using the Arial part extract of Dorema ammoniacum D. and characterised by employing UV-visible spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Transmission electron microscopy and field emission scanning electron microscopy were applied to investigate the morphological structure of the bio-synthesised SNPs. The antimicrobial activity of SNPs was studied against Gram positive (Bacillus cereus and Staphylococcus aureus) and Gram-negative (Escherichia coli and Salmonella typhimurium) bacteria by employing the disk diffusion agar process. An extremely antimicrobial effect was observed for SNPs. Utilising D. ammoniacum D. as a mediator for the synthesis of SNPs helped to save time and cost.

One-pot biosynthesis of silver nanoparticles using Iboza Riparia and Ilex Mitis for cytotoxicity on human embryonic kidney cells

Plant extracts continue gaining significant prominence in green synthesis of silver nanoparticles (AgNPs), due to their potential applications in nano-medicine and material engineering. This work reports on green synthesis of silver nanoparticles (AgNPs) from aqueous extracts of Iboza Riparia leaf and Ilex Mitis root bark with diterpenes (DTPs) and saponins (SPNs) as major components. After TEM, DLS, TGA/DSC, ATR, XRD and UV-Vis characterization, the relevant cytotoxicity studies were conducted with the MTT assay on human embryonic kidney cells (HEK293T) followed by antioxidant activity with ABTS. Overall, the AgNPs-DTPs (156nm) were found to be less toxic with 49.7% cell viability, while AgNPs-SPNs (50nm) and AgNPs-PVA (44nm) had cell viability of 40.8 and 28.0% respectively at 400μM. Based on the cytotoxicity and antioxidant activity, it is fair to report that these plant extracts have potential reducing and capping agents as they retain chemical properties on the surface of the nanoparticles.

Mosquito larvicidal activity of cadmium nanoparticles synthesized from petal extracts of marigold (Tagetes sp.) and rose (Rosa sp.) flower

Mosquitoes are blood-thirsty insects and serve as the most important vectors for spreading most notorious diseases such as malaria, yellow fever, dengue fever, and filariasis. The extensive use of synthetic mosquito repellent has resulted in resistance in mosquitoes. Therefore, the development of a reliable, eco-friendly processes for the synthesis of nano dimensional materials is an utmost important aspect of nanotechnology. In the present study, authors report absolute green synthesis of cadmium nanoparticles using marigold and rose flower petal extract. The characterization of nanomaterials was done by using UV-Vis, SEM, FTIR and fluorescent spectrophotometer analysis. Finally cadmium nanoparticles were also evaluated for their larvicidal activity of mosquito. Marigold flower petal extract shows 100 % mortality after 72 h of incubation with 10 ppm of Cd-nanoparticles. No mortality was observed in the control. Therefore, out of two flower petal mediated nanoparticles, only marigold showed better performance towards mosquito larvicidal activity than rose petal extracts. This is the first report on mosquito larvicidal activity of flower-petal mediated cadmium nanoparticles. Thus, the use of marigold petal extract to synthesize cadmium nanoparticles is a rapid, ecofriendly, and a single-step approach and the CdNps formed can be potential mosquito larvicidal agents.

Green synthesis of ZnO nanoparticles by Olive (Olea europaea)

Green synthesis of nanoparticles is superior to physical and chemical methods as it is environment-friendly and cost-effective. The present study was carried out for inducing nanoparticles synthesis by zinc nitrate in the leaves extracts of olive. Further leaves extracts were evaluated for antiradical scavenging activity by 1, 1-diphenyl-2-picryl-hydrazyl assay. Morphological and structural properties of the synthesised ZnO nanoparticles have been characterised using UV-Vis spectrophotometer, FTIR, TEM, XRD and dynamic light scattering (DLS) analysis. Further, zinc oxide nanoparticles were evaluated for antiradical scavenging activity by capacity of total antioxidant assay. Synthesised ZnO nanoparticles were confirmed by the absorption maxima at the wavelength of 370 nm. TEM image revealed that ZnO nanoparticles were spherical with average size 41 nm. FTIR investigation suggested that the flavonoids, glycosides, proteins and phenols molecules can play an important role in the stabilisation of ZnO nanoparticles.

Green synthesis of silver nanoparticles using onion extract and their application for the preparation of a modified electrode for determination of ascorbic acid

A high-quality method for one-pot biosynthesis of silver nanoparticles (AgNPs) using onion extracts as reductant and stabilizer is reported. The synthesized AgNPs were characterized by ultraviolet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). UV-Vis spectroscopy results showed that the AgNP absorption band was located at a peak of 397 nm in aqueous solution. Both XRD and TEM results confirmed that the AgNPs were mainly spherical with average diameters of 6.0 nm by TEM and about 5.3-10.2 nm calculated using XRD data. The ability of AgNPs to reduce charge transfer resistance was also investigated using electrochemical impedance spectroscopy. Finally, the effect of synthesized NPs on ascorbic acid signal was investigated by square wave voltammetry. The peak current of square wave voltammograms of ascorbic acid increased linearly with its concentration in the range of 0.4-450.0μM. The detection limit for ascorbic acid was 0.1μM.

Green synthesis of Ag nanoparticles in large quantity by cryomilling

A green synthesis of ultrapure and free standing silver nanoparticles by cryomilling.