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We synthesized silver nanoparticles using thirty Chinese plant extracts via a green synthetic strategy. UV–visible spectra showed that the silver nanoparticles have an absorbance at 450 nm. Among the thirty extracts, seven extracts (Cratoxylum formosum , Phoebe lanceolata , Scurrula parasitica , Ceratostigma minus , Mucuna birdwoodiana , Myrsine africana and Lindera strychnifolia) exhibited the successful synthesis of silver nanoparticles. These seven extracts showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power than the other extracts. The silver nanoparticles synthesized using these seven extracts were mostly spherical with high colloidal stability. The cytotoxicity of these seven silver nanoparticle samples on human lung cancer cells (A549) was clearly higher than that of the extracts alone. Furthermore, the cytotoxicity was affected by the presence or absence of fetal bovine serum. Moreover, the cytotoxicity of the silver nanoparticles synthesized with Cratoxylum formosum and Mucuna birdwoodiana extracts resulted in apoptotic cell death in A549 cells. The wound healing activity observed by the cell scratch method on mouse fibroblast cells (NIH3T3) suggested that the Lindera strychnifolia extract produced silver nanoparticles with decent activity. These results provide ample and systematic information for researchers on the green synthesis of silver nanoparticles using plant extracts. Unlabelled Image • Thirty plant extracts are used for green synthesis of silver nanoparticles. • Synthetic process is totally green and eco-friendly. • Plant extracts play a role as a reducing and a stabilizing agent. • Silver nanoparticles exert biological activities. [ABSTRACT FROM AUTHOR]

The use of nontoxic biological compounds in the synthesis of nanomaterials is an ecofriendly and cost-effective approach in nanotechnology. The present work was carried out to develop silver nanoparticles (Ag-NPs) by a green method using white tea ( Wt ) extract as reducing agent for reduction of silver nitrate as silver precursor into the lamellar space of inorganic polymer montmorillonite (Mt) as an effective protective reagent and support as well. The bioformed Wt /Ag@Mt nanocomposite (NCs) was compared with pure biosynthesized Wt /Ag-NPs under free stabilizer condition and effect of Mt stabilizer on antioxidant, cytotoxicity and structural properties were also investigated. The prepared Wt /Ag-NPs and Wt /Ag@Mt-NCs were characterized by UV–vis spectroscopy, FTIR, XRD, TEM, SEM and EDX. The interlamellar space limits were without many changes, therefore Ag-NPs formed on the exterior surface of Mt. The XRD study showed that the particles are crystalline structure in nature, with a facecentered cubic (fcc) structure. The TEM result shows the bioformed Ag-NPs are spherical in shapes with mean particle size of 19.77 ± 3.82 for Wt /Ag-NPs and 15.87 ± 2.38 nm for Wt /Ag@Mt-NCs. In vitro cytotoxicity studies on MOLT-4 cells, a dose dependent toxicity with non-toxic effect of concentration below 40 μg/mL was shown. The outcome shows that IC 50 of our green synthesized Wt /Ag@Mt-NCs was 0.0039 in comparison to 2.13329 for Doxorubicin and 0.013 μM for Cisplatin which is much better than IC 50 of these anticancer drugs and more active than them for MOLT-4 cell line. Antioxidant activity indicated that they can be applied as potential radical scavenger and also showed that DPPH activity increased in a dose dependent manner. The bio-synthesized nanoparticles can potentially useful in pharmaceutical and biomedical applications. [ABSTRACT FROM AUTHOR]

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV–vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative ( Escherichia coli , Pseudomonas aeruginosa and Vibrio cholerae ) and Gram positive ( Bacillus subtilis ) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. [ABSTRACT FROM AUTHOR]

In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) have gained importance in technological advances owing to their user friendly enhanced and efficient physical, chemical, and biological characteristics compared to their bulk counterparts. Biological synthesis of NPs by using a microorganism, enzymes, or plant extracts offers a greener and eco-friendly approach besides many advantages over physical or chemical approaches. This study reports the biosynthesis of silver nanoparticles (AgNPs) using Nostoc muscorum NCCU 442 aqueous extract as the reducing and capping agent for AgNPs synthesis. The synthesized nanoparticles were characterized by UV‐VIS spectrum, SEM, EDS, TEM, AFM, DLS and XRD. Results showed distinguishing polycrystalline nature of synthesized AgNPs with surface plasmon significant band in the size range of 6‐45nm with average 30 size nm. FT-IR study revealed the role of secondary metabolites present in aqueous extract for the synthesis of AgNPs. Biological activities of purified AgNPs as antioxidant and antibacterial potential showed the highest antibacterial activity against Staphylococcus aureus MTCC 902. Unlabelled Image • AgNP biosynthesis optimization and characterizations were done by using Nostoc musco-rum NCCU 442 aqueous extract. • Size, shape and purity of AgNP were characterized by SEM, EDS, TEM, AFM and DLS. • XRD pattern exhibited polycrystalline nature of the AgNP. • FT-IR study revealed that the secondary metabolites of extract were responsible for the synthesis of AgNP. • Biosynthesized AgNP showed significant antioxidant and antibacterial potential. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) were synthesized via a green strategy using fifty-eight plant extracts that originated from Vietnam and Indonesia. Among the fifty-eight AgNP samples, we selected six AgNP samples synthesized by the extracts of Areca catechu , Hypotrachyna laevigata , Ardisia incarnata , Maesa calophylla , Maesa laxiflora and Adinandra poilanei. Remarkably, these six extracts exhibited higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power than the other extracts. Furthermore, the contents of total phenolic compounds and reducing sugars in the six selected extracts were also higher than those in the other extracts. The six selected AgNP samples showed strong surface plasmon resonance in the range of 416–438 nm. They were all spherical shaped with an average size from 12.5 ± 1.0 nm to 21.3 ± 4.9 nm as measured by field-emission transmission electron microscopy images. The hydrodynamic sizes were measured to be 49.5–122.6 nm with negative zeta potential values. Colloidal stability was excellent on the shelf for 28 days and in cell culture medium. The cytotoxicity assessment and generation of reactive oxygen species (ROS) in A549 and HeLa cells demonstrated that the AgNP samples prepared by Ardisia incarnata , Maesa calophylla , and Maesa laxiflora showed relatively high cytotoxicity and excess ROS generation among the six selected AgNP samples. Exposure of the AgNP samples to A549 and HeLa cells resulted in cell death, which was mostly due to necrosis but slightly due to late apoptosis. Cell cycle analysis demonstrated a significant increase in the cell population in the S phase. The green-synthesized AgNPs induced cell death, suggesting anticancer prospects that may offer new insight into the development of an anticancer nanomedicine. Unlabelled Image • Fifty-eight plant extracts are used for green synthesis of silver nanoparticles. • Synthetic process is totally sustainable and green. • Silver nanoparticles are cytotoxic and generate ROS in cancer cells. • Silver nanoparticles induce cell death via mostly necrosis. [ABSTRACT FROM AUTHOR]

Phytochemicals sources have been extensively used as reducing and capping agents for synthesis of nanoparticles (NPs). However, morphology-controlled synthesis and shape/size dependent applications of these NPs still need to be explored further, and there is a need to develop a way in which particular and optimized phytochemicals result in the desired NPs in lesser time and cost with higher reproducibility rate. The present study is focused on morphology-controlled synthesis and shape/size dependent application of silver NPs based on the fractionated phytochemicals of Elaeagnus umbellata extract (EU). Unlike other approaches, in this study the reaction parameters such as time, temperature, pH, stirring speed and concentration of the precursor solutions were not altered during the optimization process. The fractionated phytochemicals were used separately for the synthesis of AgNPs, and the synthesized NPs were characterized by UV–visible, FT-IR, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Our findings suggested that the constituents of the extract fractions varied with the selection of the extraction solvent, and the shape/size, bactericidal properties and toxicity of the NPs have a strong correlation with the phytochemicals of the plant extract. The fractionated phytochemicals present in the water fractions (EUW) resulted in monodispersed spherical AgNPs in the size about 40 nm. The NPs have significant stability in physiological conditions (i.e. temperature, pH and salt), have good antibacterial activity, and were found to be non-toxic. Furthermore, AFM and SEM analysis exposed that the NPs killed the bacteria by disturbing the cellular morphology and releasing the cellular matrix. Our results justify the use of different fractions of plant extract to obtain detail implications on shape, size, antibacterial potential and toxicity of AgNPs. This is the first step in a controllable, easy and cheap approach for the synthesis of highly stable, uniform, non-toxic and bactericidal AgNPs using five fractions of EU. The findings suggested that the synthesized NPs, particularly from EUW, could be used in pharmaceutical and homeopathic industry for the development of antibacterial medications. Unlabelled Image • Bio-inspired synthesis of AgNPs by using five fractions of Elaeagnus umbellata extract. • The use of fractionated phytochemicals in the extract for controllable synthesis of AgNPs. • AgNPs exhibited promising antibacterial activity against gram-positive and gram-negative bacteria. • Phytochemicals in the extract provides a simple, efficient and cost-effective way for the synthesis of stable and non-toxic AgNPs. • Use of AFM and SEM for morphological characterization of S. aureus and E. coli. [ABSTRACT FROM AUTHOR]