Green Synthesis Of Gold Nanoparticles Research Articles

Green synthesis of gold nanoparticles from Fritillaria cirrhosa and its anti-diabetic activity on Streptozotocin induced rats

To evaluate the anti-diabetic effect of Fritillaria cirrhosa gold nanoparticles on Streptozotocin (STZ) stimulated diabetic preclinical models. The albino rats of either sex were equally distributed to five different groups. Group-I represented as Control; Group-II represented as diabetic control (STZ alone); Group-III represented as 10 mg/kg body weight of Fritillaria cirrhosa gold nanoparticles + diabetes; Group-IV represented as 20 mg/kg body weight of Fritillaria cirrhosa gold nanoparticles + diabetes; Group-V represented as 0.1 mg/kg body weight of glibenclamide + diabetes. The animals were killed after the experimental period. The blood and organs samples were gathered and stored for the additional investigations. The gold nanoparticles were inspected via the UV spectrophotometer, HR-TEM, XRD and FT-IR techniques. The bodyweight, kidney and liver weight were tabulated. The food and water consumption were monitored in all the experimental rats. The serum markers, hepatic markers and renal markers were quantified in both normal and investigational rats. The lipid peroxidation and antioxidant status were quantified in the control and experimental rats. The histopathological alterations were also studied in all the experimental animals. The standard drug glibenclamide was used to compare the synthesized AuNPs. The study revealed that the AuNPs treatment restores the serum, hepatic and renal marker in the STZ-challenged diabetic rats. The AuNPs treatment modulates the antioxidants level and decreased the lipid peroxidation by its antioxidant properties. The pathology results revealed that the AuNPs treatment induces the regeneration of islets cells of pancreas in the experimental rats. The research study proved that the Fritillaria cirrhosa AuNPs exerts anti-diabetic properties.

Influence of Adding Green Synthesized Gold Nanoparticles to Tris-Extender on Sperm Characteristics of Cryopreserved Goat Semen

There are various challenges during semen cryopreservation used for artificial insemination, oxidative stress is considered as the major factor. Usage of nano-particle materials is an efficient tool to overcome these challenges. In the present article, effects of adding green synthesized gold nanoparticles (GSGNPs, 5; 10ppm/mL) to Tris-extender on sperm characteristics in post-equilibrated and post-thawed semen. Apoptosis and sperm ultrastructure post-thawed were also examined as well as enzyme activity and antioxidant status in post-thawed extender of goat semen were evaluated. Supplementation of GSGNPs (10 ppm) increased (P<0.05) motility, livability, and membrane integrity post-equilibration, and also in addition to acrosome integrity post-thawing. Also, viable sperm increased (P<0.05), early apoptotic, apoptotic, and necrotic sperm decreased (P<0.05) by 10 ppm GSGPNs. In the extender of thawed semen, AST and ALT activities were not affected, total antioxidant capacity and catalase activity were higher (P<0.05), while malondialdehyde decreased (P<0.05) by 10 ppm GSGNPs. Frequency distribution of sperm cells with intact plasma or acrosomal membranes increased (P<0.05), while of those with swollen plasma membranes or typical acrosome reaction decreased (P<0.05). However, frequency distribution of sperm cells with slightly swollen or lost plasma membranes as well as atypical acrosome reaction and lost acrosomal membrane was not affected by GSGNPs. Transmission electron microscopy examination revealed no entry of GSGNPs with sperm cells.The present article may suggest considerable addition of GSGNPs at a level of 10 ppm/mL to Tris-extender of cryopreserved goat semen during cryopreservation.

Preparation of Spherical Gold Nanoparticles Capped by Fragaria ananassa (Strawberry) Fruit Extract and their Catalytic Activity for Degradation of Industrial Dyes

The prospect of developing new approaches in the assembly of noble metal nanoparticles and its functions has been garnering intense interest among researchers in various fields. The green synthesis method is an evolving trend as it is environment benign and aids in large-scale formation of nanoparticles. The versatile properties of green synthesized gold nanoparticles (AuNPs) like surface plasmon resonance, stability and morphology are examined by UV-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), zeta potential (ZP) and high resolution transmission electron microscopy (HRTEM) studies at pH 7. Fourier transform-infrared (FT-IR) analysis confirms the pivotal role of anthocyanins and polyphenols in Fragaria ananassa (strawberry) fruit extract for the capping of AuNPs. The size of gold nanoparticles is in the range of 10 to 40 nm and they exhibit greater negative value of zeta potential. The catalytically active AuNPs follow the pseudo-first order kinetic model and takes 10 min for rapid degradation and adsorption of methylene blue dye from aqueous solution. These results confirm that Fragaria ananassa has a remarkable function in the plant-mediated synthesis of AuNPs and thus can emerge as a positive platform to convert water pollutants into harmless molecules.

Effect of Green Synthesis of Gold Nanoparticles (AuNPs) from Hibiscus sabdariffa on the Aggregation of α-Lactalbumin

Amyloidosis are a hereditary or acquired disorders, which are associated with misfolding of normally soluble, functional peptides and proteins, and their conversion into contentious aggregation can cause amyloid fibrils. These fibrils reduce function of the proteins and with generation of toxic intermediates in the process of self-assembly cause amyloid diseases such as Alzheimer, Parkinson, etc. Nanoparticles are materials with a dimension of 1–100 nm that influence the process of protein fibrillation since nanoparticles mediated by chemical methods have been show side effects, biological methods have been preferred due to its safety for human therapeutic use. In this study, the effect of gold nanoparticle produced from hibiscus on the amyloid formation of α-lactalbumin was evaluated using light scattering absorption, fluorescence (ThT assay, intrinsic fluorescence assay and ANS binding assay), TEM, CD spectroscopy and SDS-PAGE. α -Lactalbumin has been chose as a good sample for study the amyloid formation due to the formation of molten globule state. The results show that AuNPs inhibit formation of amyloid fibrils in reduced α-lactalbumin. This protective effect resulted are due to increase protein adsorption to the surface of the nanoparticles and therefore prevents their structural changes. Nanoparticle by binding to the monomer prevented them from join together and elongation the core of amyloid fibrils. Finally, the results show that biosynthesized AuNPs mediated by hibiscus can be used as effective therapeutic agent for prevention of formation amyloid and treatment of amyloid disease.

New reductant-free synthesis of gold nanoparticles-doped chitosan-based semi-IPN nanogel: A robust nanoreactor for exclusively sensitive 5-fluorouracil sensor

We report a novel class of chitosan (CS)-based hybrid semi-interpenetrating nanogel catalyst by the reductant-free green synthesis of gold nanoparticles (Au NPs) within the CS-poly(methacrylic acid) (Au@CS-PMAA) polymer network. The covalently cross-linked Au@CS-PMAA nanogel with CS chains semi-interpenetrating (semi-IPN) in the PMAA cross-linked network show superior colloidal stability and improved catalytic activity. The synthesized Au@CS-PMAA semi-IPN nanogel was applied as a superior modifier to create a new and sorely selective electrochemical sensing platform for the determination of antileukemic drug 5-fluorouracil (5-FU). The existence of –OH and –COOH groups in the CS and PMAA offers numerous binding sites for 5-FU. This assures the incorporation of Au NPs which affords a larger surface area and ameliorate electrical conductivity. Besides, the synergic effect amid both compounds improves the detection of 5-FU. Under optimal conditions, the constructed sensor offered a good performance in determination of 5-FU with a wide linear range from 0.1–497 μM and low detection limits of 0.03 μM, respectively. Further, this study proved that the fabricated sensor could be useful for analysis of 5-FU in actual human blood serum samples.

Green Synthesis of Gold Nanoparticles Using Longan Polysaccharide and their Reduction of 4-nitrophenol and Biological Applications

The green synthesis of gold nanoparticles (Au NPs) for catalytic and biological applications has been drawing great attention. To compare with plant extracts, the polysaccharides may be good reducing and stabilizing agents. In this work, we describe the preparation of longan polysaccharide stabilized gold nanoparticles (Aun-LP NPs) by reduction of gold ions using a green synthetic method. The formation of gold nanoparticles (Au NPs) was confirmed by UV-Vis spectra. TEM showed that Au NPs had a small size (7.8–15.6[Formula: see text]nm) and were highly dispersed without any aggregation. XPS confirmed that the surface elemental composition of Aun-LP NPs was C, O, and Au. DLS demonstrated that Aun-LP NPs had good stability and negative zeta potential. In addition, Aun-LP NPs had high catalytic activity for the reduction of 4-nitrophenol. More importantly, Aun-LP NPs had ignorable cytotoxicity towards HeLa cells and showed good antioxidant activity. Taken together, the results indicated that longan polysaccharide can be used as reducing agents and stabilizers for the preparation of metallic nanoparticles, and the product had wide applications.

Green synthesis of gold nanoparticles supported in Al-pillared bentonite using aqueous leaf extracts of Dracaena angustifolia and their use for reductive degradation of methyl orange

We obtained the green synthesis of gold nanoparticles (AuNPs) using suji leaf extract (Dracaena angustifolia) and used the AuNPs to reduce methyl orange. The active substance in suji leaf extract was determined using phytochemical tests to identify components such as terpenoid, steroid, alkaloid, polyphenol, flavonoid, and saponin. The catalyst Al–bentonite@AuNP was prepared by immobilizing HAuCl4 in Al–pillared bentonite, which was then reduced using various concentrations of suji leaf extract [0.1 %–1 % (w/v)]. The AuNPs were characterized using UV–vis spectroscopy and transmission electron microscopy, and the Al–bentonite@AuNP catalyst was characterized using Fourier transform infrared spectroscopy and X-ray diffraction. The application of Al–bentonite@AuNP as catalyst in the reductive degradation of methyl orange yields a degradation percent of up to 34.5 %.

Formononetin in Radix Hedysari extract-mediated green synthesis of gold nanoparticles for colorimetric detection of ferrous ions in tap water.

This study linked natural plant materials and nanomaterials; reporting an environmentally friendly, non-toxic and efficient method for the green synthesis of gold nanoparticles (AuNPs) using an ethyl acetate extract of Radix Hedysari (EAR). The components of the extract were identified using HPLC and it was found that formononetin accounted for more than 90% of the total contents. We predicted that formononetin in EAR plays a crucial role in green synthesis. Thus, formononetin was used as a standard reductant to synthesize AuNPs, and the result confirmed our prediction. The synthetic mechanism was also discussed in detail in the article. Moreover, EAR–AuNPs realized the sensitive and selective colorimetric detection of ferrous ions (Fe2+) among other metal ions, and were applied to spiked tap water with a low detection limit of 1.5 μM in a wide range from 10 μM to 500 μM. EAR–AuNPs were green synthesized using Radix Hedysari extract for the first time and were successfully applied in real sample detection.

Antimicrobial, antioxidant and anticancer activities of gold nanoparticles green synthesized using Mangifera indica seed aqueous extract

In this study, gold nanoparticles (AuNPs) were synthesised using seed extract of mango (Mangifera indica) which is considered as waste and generally thrown away into the environment. The bioactive molecules in the seed act as reducing agent to synthesise AuNPs without using any external agent. The characterisation of green synthesised AuNPs was done using various spectroscopic techniques. Visual colour change from colourless to ruby red colour confirmed the formation of AuNPs which was further confirmed by maximum absorption peak at 550 nm by UV-spectra. Crystalline nature was confirmed by XRD technique while round, triangle and irregular shape and 19.45 nm size was confirmed by TEM and SAED analysis. FTIR analysis confirmed the presence of alcohol or phenol, carboxylic acid, ketones, amines, aromatic amines, aliphatic amines, alkyl halides and alkynes in M. indica seed which were responsible for the reduction of gold to AuNPs. The green synthesised AuNPs were evaluated for their antimicrobial, antioxidant and cytotoxic potential. They showed moderate antibacterial, cytotoxic and dose-dependent antioxidant activity. Seeds of M. indica instead of discarding can be successfully utilised for AuNPs synthesis which can be used as a natural source of antimicrobial, antioxidant and anticancer agent. Highlights Green synthesis of gold nanoparticles (AuNPs) from fruit (Mangifera indica) waste (seed). Characterisation using various spectroscopic techniques: UV-Vis spectroscopy, Zeta potential, FTIR, XRD and TEM analysis. Synthesized AuNPs were round, triangle and irregular in shape and 19.45 nm in size. Antimicrobial activity of AuNPs against 14 microorganisms. Antioxidant activity of AuNPs in terms of DPPH, SO and ABTS. Cytotoxic activity against HeLa, MCF-7 and fibroblast normal cell lines.

Biosynthesis of gold nanoparticles for detection of dichlorvos residue from different samples

In the present study, we report the green synthesis of gold nanoparticles (Au-Nps) using chloroauric acid and leaf extract of Citrus limonum. This protocol was found to be efficient due to the application of greener tools like renewable aqueous solvent, plant extract bio-reduction and ultrasonication for the synthesis of Au-Nps with well-controlled morphology. This method helpful for qualitative and quantitative analysis of organophosphate insecticide, “dichlorvos” extracted from samples like soil, cloth, and viscera. The characterization of synthesized Au-Nps was done by EDS, FE-SEM, UV–VIS, TLC, and FT-IR.

Markable Green Synthesis of Gold Nanoparticles Used As Efficacious Catalyst for the Reduction of 4-Nitrophenol

Markable Green Synthesis of Gold Nanoparticles Used As Efficacious Catalyst for the Reduction of 4-Nitrophenol

Green Nanotechnology-based Gold Nanomaterials for Hepatic Cancer Therapeutics: A Systematic Review

The objective of the current study was to systematically review the in-vitro anticancer activity of green synthesized gold nanoparticles (AuNPs) against hepatic cancer cells. The articles were identified through electronic databases, including PubMed, Scopus, Embase, Web of Science, Science Direct, ProQuest, and Cochrane. In total, 20 articles were found eligible to enter into our systematic review. Our findings showed that 65% of the articles used herbal extracts for the synthesis of AuNPs. Significantly, almost all of the articles stated the biofabrication of AuNPs below 100 nm in diameter. Impressively, most of the studies showed significant anticancer activity against HepG2 cells. Molecular studies stated the induction of apoptosis through the AuNPs-treated cells. We provided valuable information about the molecular mechanisms of AuNPs-induced cytotoxicity against HepG2 cells as well as their biocompatibility. The studies represented that AuNPs can be effective as anticancer drug nanocarrier for drug delivery systems. In addition, AuNP surface functionalization provides an opportunity to design multifunctional nanoparticles by conjugating them to diagnostic and/or therapeutic agents for theranostic purposes. Overall, our findings depicted considerable biogenic AuNPs-induced cytotoxicity, however, future studies should assess the anticancer activity of biogenic AuNPs through in-vivo studies, which was missing from such studies.

Novel green synthesis of Boswellia serrata leaf aqueous extract conjugated gold nanoparticles with excellent anti‐acute myeloid leukemia property in comparison to mitoxantrone in a leukemic mice model: Introducing a new chemotherapeutic drug

The present research confirms the capacity of aqueous extract of Boswellia serrata grown under in vitro condition for the green synthesis of gold nanoparticles (AuNPs). Also, we showed the cytotoxicity, antioxidant, and anti‐acute myeloid leukemia properties of AuNPs compared to mitoxantrone in a leukemic mouse model. The synthesized AuNPs were characterized using several techniques including XRD, TEM, FE‐SEM, UV–Vis, and FT‐IR. From the XRD pattern, four distinct diffraction peaks at 38.2°, 44.2°, 64.7° and 77.4° are indexed as (111), (200), (220) and (311) planes of FCC metallic gold. TEM and FE‐SEM images revealed an average diameters of 15–30 nm for the nanoparticles. FT‐IR findings offered antioxidant compounds in the nanoparticles were the sources of reducing power, reducing gold ions to AuNPs. UV–Vis revealed an absorption band at 536 nm that is related to the surface plasmon resonance of AuNPs. In vivo design, induction of acute myeloid leukemia was done by DMBA in 75 mice. Then, the mice were randomly divided into six subgroups, including untreated, control, HAuCl4, B. serrata, AuNPs, and mitoxantrone. AuNPs (In the dose of 1 mg/kg body weight) similar to mitoxantrone, significantly (p ≤ 0.05) increased the platelet, lymphocyte, and RBC parameters and the anti‐inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and reduced the weights and volumes of liver and spleen and their sub‐compartment, the total WBC, blast, monocyte, neutrophil, eosinophil, and basophil counts, and the pro‐inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα) as compared to the untreated mice. By quantitative Real‐Time PCR, S1PR1 and S1PR5 mRNA expression in lymphocytes were significantly (p ≤ 0.05) increased by treating the leukemic mice with the AuNPs and mitoxantrone. In vitro design, AuNPs similar to mitoxantrone had low cell viability dose‐dependently against Human HL‐60/vcr, 32D‐FLT3‐ITD, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Besides, the DPPH assay showed similar antioxidant potentials for AuNPs and mitoxantrone. In conclusion, the results of this research indicated the excellent capacity of synthesized gold nanoparticles using B. serrata leaf aqueous extract in the treatment of acute myeloid leukemia in leukemic mice.

Green pyomelanin-mediated synthesis of gold nanoparticles: modelling and design, physico-chemical and biological characteristics

BackgroundSynthesis of nanoparticles (NPs) and their incorporation in materials are amongst the most studied topics in chemistry, physics and material science. Gold NPs have applications in medicine due to their antibacterial and anticancer activities, in biomedical imaging and diagnostic test. Despite chemical synthesis of NPs are well characterized and controlled, they rely on the utilization of harsh chemical conditions and organic solvent and generate toxic residues. Therefore, greener and more sustainable alternative methods for NPs synthesis have been developed recently. These methods use microorganisms, mainly yeast or yeast cell extract. NPs synthesis with culture supernatants are most of the time the preferred method since it facilitates the purification scheme for the recovery of the NPs. Extraction of NPs, formed within the cells or cell-wall, is laborious, time-consuming and are not cost effective. The bioactivities of NPs, namely antimicrobial and anticancer, are known to be related to NPs shape, size and size distribution.ResultsHerein, we reported on the green synthesis of gold nanoparticles (AuNPs) mediated by pyomelanin purified from the yeast Yarrowia lipolytica. A three levels four factorial Box–Behnken Design (BBD) was used to evaluate the influence of temperature, pH, gold salt and pyomelanin concentration on the nanoparticle size distribution. Based on the BBD, a quadratic model was established and was applied to predict the experimental parameters that yield to AuNPs with specific size. The synthesized nanoparticles with median size value of 104 nm were of nanocrystalline structure, mostly polygonal or spherical. They exhibited a high colloidal stability with zeta potential of − 28.96 mV and a moderate polydispersity index of 0.267. The absence of cytotoxicity of the AuNPs was investigated on two mammalian cell lines, namely mouse fibroblasts (NIH3T3) and human osteosarcoma cells (U2OS). Cell viability was only reduced at AuNPs concentration higher than 160 µg/mL. Moreover, they did not affect on the cell morphology.ConclusionOur results indicate that different process parameters affect significantly nanoparticles size however with the mathematical model it is possible to define the size of AuNPs. Moreover, this melanin-based gold nanoparticles showed neither cytotoxicity effect nor altered cell morphology.

Process optimization for green synthesis of gold nanoparticles mediated by extract of Hygrophila spinosa T. Anders and their biological applications

Plant extract-mediated green synthesis of gold nanoparticles (AuNPs) and their biomedical application is currently gaining huge interest in the field of nanotechnology . In the present study, AuNPs were synthesized using Hygrophila spinosa aqueous extract (HSAE). The formation of AuNPs was confirmed by observing color change and characteristic absorbance peak for surface plasmon resonance by UV–Vis spectroscopy. Different reaction parameters such as HSAE concentration, salt concentration, pH, reaction time and temperature were optimized for biosynthesis of AuNPs. The NPs were characterized for particle size, surface morphology , crystallinity , elemental composition and surface functionalities. Cytotoxicity of the AuNPs was studied against different cancer cell lines by MTT assay and antioxidant potential as total antioxidant capacity was also evaluated. The biosynthesized AuNPs were small in size and negatively charged. Phytochemical screening of HSAE, and FTIR spectrum of synthesized AuNPs demonstrated participation of various groups of chemical compounds as capping and stabilizing agents in biosynthesis of AuNPs. The green synthesized AuNPs exhibited significantly higher anticancer activity compared to HSAE against breast, ovarian, glioblastoma/brain and multi-drug resistant ovarian cancer cell lines. Antioxidant activity of the synthesized AuNPs was less than HSAE. The biosynthesized AuNPs could be studied further to access their potency in the treatment and imaging of various cancers. • Green synthesis of AuNPs has been carried out with Hygrophila spinosa aqueous extract (HSAE). • Concentration of HAuCl 4 solution, pH, reaction incubation temperature & time, and concentration of HSAE have been optimized for synthesis of AuNPs. • Characterization by UV–Vis, FTIR, SEM, TEM, EDS and XRD confirm that HSAE could synthesize AuNPs. • Synthesized AuNPs exhibited promising antioxidant and anticancer activities.

Nitrate Reductase mediated synthesis of surface passivated nanogold as broad-spectrum antibacterial agent

The green synthesis of gold nanoparticles has attracted tremendous interest owing to their unique physicochemical properties and widespread applications which are primarily size-dependent. The stability, less reaction time, and use of biological resources as novel nanofactories as an alternative to conventional synthesis strategies are the main objectives of green synthesis approaches. However, to attain size-controlled synthesis from the biogenic route is still a challenge. Hence, use of nontoxic stabilizers becomes increasingly essential. Herein, we describe an emerging, simple, nonconventional approach to synthesize stable and size-controlled biogenic nanogold using cell lysate supernatant containing nitrate reductase of Bacillus licheniformis in the presence of Tween 20 and dodecanethiol respectively. The face-centered central composite design used for the optimization of gold nanoparticles (AuNPs) biosynthesis. The maximum AuNPs biosynthesis obtained using the optimized media variables, glucose (2.1 g/L), peptone (14.05 g/L), yeast extract (4.14 g/L), and potassium nitrate (3.91 g/L) was 0.769 a.u. Highly stable monodispersed nanogold of 10.4 ± 0.6 nm and 12.5 ± 0.9 nm sizes arranged in ordered self-assembly was obtained. The stability profile and kinetics of bioreduction was evaluated with respect to time, and the involvement of the nitrate reductase enzyme in bioreduction was validated by inhibitor study. The physicochemical properties of biogenic nanoparticles were characterized using multiple spectroscopy and microscopy techniques. The obtained nanogold demonstrated excellent bactericidal property against both gram-negative and gram-positive bacteria in size-dependent manner and thus could find tremendous utility in clinical, biological, and environmental applications as a broad-spectrum antibacterial agent.

An aptasensor based on electrosynthesized conducting polymers, Cu2O–carbon dots and biosynthesized gold nanoparticles, for monitoring carcinoembryonic antigen

Current work proposes an inimitable composite, with great electrical conductivity and quite enhanced surface area, (including conducting polymers (poly (cathechol)), Cu2O–carbon dots and green synthesized gold nanoparticles) for detecting acute carcinoembryonic antigen. At current work, the electropolymerization was offered instead of enzyme-catalyzed polymerization of poly (catechol). Four cost-effective electrochemical techniques (Differential Pulse Voltammetry, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Crono amperometry) were engaged to investigate aptasensors construction, immobilization, hybridization, sensitivity, selectivity, repeatability, long-term stability and real PCR sample detections. According to the data, the values of Ipeak is linearly related to the logarithm of the concentrations of carcinoembryonic antigen in the range from 1.0 pg mL-1 to 0.001 g mL-1, with a detection limit of 0.19 pg mL-1 for the target antigen (carcinoembryonic antigen). Keywords: conducting polymer, carbon quantum dots, green synthesize, elctrosynthesize, screen-printed electrode, carcinoembryonic antigen. Keywords: conducting polymer, carbon quantum dots, green synthesize, elctrosynthesize, screen-printed electrode, carcinoembryonic antigen

Green Synthesis of Gold Nanoparticles from Vitex negundo Leaf Extract to Inhibit Lipopolysaccharide-Induced Inflammation Through In Vitro and In Vivo

Gold nanoparticles (AuNPs) have wide applications in the field of diagnosis and treatment of diseases which are attributed to their compatibility and high efficiency of drug delivery, because of their eco-friendly nature and easy handling. In the current study, we have used an extract of Vitex negundo, a traditional anti-inflammatory folk medicine in India and synthesized gold nanoparticles (VnAuNPs), to know the effects of anti-bacterial, antioxidant, and anti-inflammatory properties both in vivo and in vitro. V. negundo leaf extracts (VnLE) per se yielded high flavonoids, saponins, tannins, alkaloids, glycosides, phenols, terpenoids. The synthesized VnAuNPs in leaf extracts was confirmed by UV–vis spectra at 543 nm and further by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and through Dynamic light scattering (DLS). The FTIR showed the peaks at 3345, 1638, 692, 683, 662 cm−1 which are responsible for the reduction and capping of gold nanoparticles. The size and shape of the AuNPs were determined by SEM. DLS study analysed the particle size distribution of AuNPs. The VnAuNPs showed significant antibacterial activity on both gram positive and negative bacteria. VnAuNPs also showed strong antioxidant (DPPH, H2O2 scavenging, Nitric oxide scavenging power and reducing power) activities when compared to VnLE extract. The VnAuNPs exhibited strong anti-inflammatory activities (COX-2, lipoxygenase and xanthine oxidase inhibitory activity) in in vitro (HeLa cell model) and in vivo study of carrageenan induced paw edema model in Swiss albino mice (paw edema and acetic acid-induced writhing test). Results suggested that the synthesized VnAuNPs are potential candidates for treating inflammatory diseases and may find application in clinical studies.

Green synthesis of gold nanoparticles: Preparation, characterization, cytotoxicity, and anti-bacterial activities

Abstract Synthesis of nanostructures using green chemistry has been popular owing to the exciting properties and innovative applications of these nanostructures. Novel, cost-effective, and eco-friendly gold nanoparticles (Au NPs) were synthesized using a mix of Olea europaea (OE) fruit extract and Acacia nilotica (AN) husk extract. The synthesized Au NPs were characterized by UV–visible spectroscopy, and the average NP size (44.96 nm) was measured by a Zetasizer. A more detailed characterization was performed using Fourier transform infrared spectroscopy, scanning, and transmission electron microscopy and electron microscopy with energy dispersive spectroscopy. The cytotoxicity of the synthesized OEAN Au NPs was evaluated using an MTT assay on breast (MCF-7), colon (TCT-116), and hepatocellular (HCepG-2) carcinoma cells. The antibacterial activity of the synthesized OEAN Au NPs was investigated using a disc diffusion method. The synthesized Au NPs exhibited moderate antibacterial activity against the bacterial strains used and profound anticancer activity against different cell lines used.

Etlingera elatior-Mediated Synthesis of Gold Nanoparticles and Their Application as Electrochemical Current Enhancer.

This work presents a simple green synthesis of gold nanoparticles (AuNPs) by using an aqueous extract of Etlingera elatior (torch ginger). The metabolites present in E. elatior, including sugars, proteins, polyphenols, and flavonoids, were known to play important roles in reducing metal ions and supporting the subsequent stability of nanoparticles. The present work aimed to investigate the ability of the E. elatior extract to synthesise AuNPs via the reduction of gold (III) chloride hydrate and characterise the properties of the nanoparticles produced. The antioxidant properties of the E. elatior extract were evaluated by analysing the total phenolic and total flavonoid contents. To ascertain the formation of AuNPs, the synthesised particles were characterised using the ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) microscopy, and dynamic light scattering (DLS) measurement. The properties of the green synthesised AuNPs were shown to be comparable to the AuNPs produced using a conventional reducing agent, sodium citrate. The UV-Vis measured the surface plasmon resonance of the AuNPs, and a band centered at 529 nm was obtained. The FTIR results proved that the extract contained the O-H functional group that is responsible for capping the nanoparticles. The HRTEM images showed that the green synthesized AuNPs were of various shapes and the average of the nanoparticles’ hydrodynamic diameter was 31.5 ± 0.5 nm. Meanwhile, the zeta potential of −32.0 ± 0.4 mV indicates the high stability and negative charge of the AuNPs. We further successfully demonstrated that using the green synthesised AuNPs as the nanocomposite to modify the working surface of screen-printed carbon electrode (SPCE/Cs/AuNPs) enhanced the rate of electron transfer and provided a sensitive platform for the detection of Cu(II) ions.