<Emphasis Type="Italic">Stachys lavandulifolia</Emphasis> and <Emphasis Type="Italic">Lathyrus</Emphasis> sp. Mediated for Green Synthesis of Silver Nanoparticles and Evaluation Its Antifungal Activity Against <Emphasis Type="Italic">Dothiorella sarmentorum</Emphasis>

In this study, silver nanoparticles (AgNPs) were biosynthesized using Stachys lavandulifolia and Lathyrus sp. The first sign of the reduction of silver ions to AgNPs was the change in color of S. lavandulifolia and Lathyrus sp. extracts changed into dark brown and auburn after treating with silver nitrate, respectively. The UV–Vis spectroscopy of reaction mixture (extract+silver nitrate) produced by S. lavandulifolia and Lathyrus sp. showed the strong adsorption peaks at ?440 and 420 nm, respectively. The transmission electron microscope images showed the synthesis of AgNPs using S. lavandulifolia and Lathyrus sp. with an average size of 7 and 11 nm, respectively. The result of X-ray diffraction pattern showed four diffraction peaks at 38°, 44°, 64°, and 77° for both types of biosynthesized AgNPs. Fourier transform infrared spectroscopy showed the possible role of involved proteins and polyhydroxyl functional groups in the synthesis process of AgNPs. Inductively coupled plasma analysis determined the conversion rate (percentage) of silver ions to silver nanoparticles in reaction mixtures of S. lavandulifolia and Lathyrus sp. 99.73 and 99.67 %, respectively. In addition, antifungal effect of AgNPs, synthesized by both extracts, was studied separately on mycelial growth of Dothiorella sarmentorum, in a completely randomized design on potato dextrose agar (PDA) medium. The inhibition rate of mycelial growth was strongly depended on the density of AgNPs and it strongly increased with increasing the density of AgNPs in the PDA medium. AgNPs more than 90 % of them inhibited from the mycelia growth of the fungus at the concentration of 40 µg/mL and higher.     

A Novel Green Synthesis of Silver Nanoparticles Using <Emphasis Type="Italic">Rubus crataegifolius</Emphasis> Bge Fruit Extract

We report a facile, cost effective, and environmentally friendly green chemistry method for preparing silver nanoparticles (AgNPs) using Rubus crataegifolius bge (RCB) fruit extract. The amount of the fruit extract used was found to be important parameters in the growth of AgNPs. In this study, the effect of RCB fruit extract on the synthesis of AgNPs was studied using UV–Vis spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), and dynamic light scattering analyses were performed to characterize the RCB fruit extract-stabilized AgNPs. The formation of the AgNPs was confirmed by the color change of the reaction medium and the absorbance peak observed at 420 nm. The XRD analysis confirmed the face centered cubic structure of the AgNPs. The catalytic property of the as-synthesized AgNPs was analyzed for the reduction of 4-nitrophenol to 4-aminophenol.     

Inhibitory Effect of Biosynthesized Silver Nanoparticles from Extract of <Emphasis Type="Italic">Nitzschia palea</Emphasis> Against Curli-Mediated Biofilm of <Emphasis Type="Italic">Escherichia coli</Emphasis>

Extended spectrum beta lactamase (ESBL) are emerging beta-lactamases in Gram-negative pathogens, causing serious problems in hospitalized patients worldwide. Biofilm mode of virulence has decreased the efficiency of antibiotics used for treatment against ESBL pathogens. Therefore, there is an urgent need for alternative agents such as nanoparticles that can prevent and inhibit the biofilm formation. The aim of the present study was to inhibit the biofilm formed by ESBL-producing Escherichia coli using silver nanoparticles (AgNPs) synthesized with fresh water diatom (Nitzschia palea). AgNPs were characterized using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and XRD. AgNPs at their biofilm inhibitory concentration (BIC) of 300 ng ml^?1 significantly reduced the biofilm formed by E. coli. Interestingly, Congo red assay revealed the reduction of curli, essential for biofilm formation in the presence of AgNPs. Light and CLSM examination of the biofilm images also validated that in the presence of AgNPs, the biofilm architecture was disintegrated and the thickness was significantly reduced. Overall, the present study exemplifies the use of AgNPs as a plausible alternative for conventional coating agents on implant devices to prevent and control biofilm-associated urinary tract infections.     

Structure and Stability of Gold Nanoparticles Synthesized Using <Emphasis Type="Italic">Schinus molle</Emphasis> L. Extract

In this work, we exhibited the results of the green synthesis of gold nanoparticles by aqueous extract of Schinus molle L. leaves. The chemical reaction was carried out by varying the plant extract/precursor salt ratio concentration in the aqueous solution. The structural characterization of the nanoparticles was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD analysis showed that the as-synthesized AuNPs have a face-centered cubic structure. SEM and TEM observations indicated that most of the obtained particles have multiple twinning structures (MTP). The synthesized Au-MTP have particle sizes in the range of 10–60 nm, most of them with an average size of about 24 nm. However, triangular Au plate particles were also obtained, having an average size of 180 nm. Fourier transforms infrared spectroscopy and shows that the functional groups responsible for the chemical reduction of AuNPs are phenolic compounds present in the S. molle L. leaf.     

<Emphasis Type="Italic">Z</Emphasis>-and <Emphasis Type="Italic">E</Emphasis>-conformers of <Emphasis Type="Italic">N</Emphasis>-chloroacetylcytisine

N-Chloroacetylcytisine was synthesized by acylation of (–)-cytisine. Stable Z- and E-conformers with respect to rotational isomerism around the N-12–CO bond were found in PMR spectra at room temperature. The point at which PMR resonances of the Z- and E-conformers coalesced upon heating was measured. The transition barrier between the conformers was estimated.     

Biosynthesis of Silver Nanoparticles by <Emphasis Type="Italic">Geotricum</Emphasis> sp.

Nanoparticles are usually 1–100 nm in each spatial dimension considered as building blocks of the next generation of optoelectronics, electronics, and various chemical and biochemical sensors. In the synthesis of nanoparticles use of microorganisms emerges as an eco-friendly and exciting approach that reduce waste products (ultimately leading to atomically precise molecular manufacturing with zero waste); the use of nanomaterials as catalysts for greater efficiency in current manufacturing processes by minimizing or eliminating the use of toxic materials (green chemistry principles); the use of nanomaterials and nanodevices to reduce pollution (e.g. water and air filters); and the use of nanomaterials for more efficient alternative energy production (e.g. solar and fuel cells). Fungi have many advantages for nanoparticle synthesis compared with other organisms. In this study, Geotricum sp. found to successfully produce Ag nanoparticles. Geotricum sp. was grown in SDA (Sabro Dextrose Agar) medium at 25 ± 1 °C for 96 h. The mycelia were used to convert silver nitrate solution into nano-silver. Silver nanoparticles were synthesized using these fungi (Geotricum sp.) extracellularly. UV–VIS spectroscopy, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy images shows the nanoparticle formation in the medium. Energy-dispersive X-ray spectroscopy (EDX) also confirmed that silver nanoparticles in the range of 30–50 nm were synthesized extracellularly. FTIR analyses confirmed the presence of amide (I) and (II) bands of protein as capping and stabilizing agent on the surface of nanoparticles.     

Green Synthesis of Silver Nanoparticles Using <Emphasis Type="Italic">Commiphora caudata</Emphasis> Leaves Extract and the Study of Bactericidal Efficiency

The present study reports the synthesis of silver nanoparticles (Ag NPs) from silver nitrate solution using leaf extracts of Commiphora caudata. The formation of Ag NPs in the colloidal solution is confirmed by UV–Vis spectroscopy analysis. The identification of biomolecules is analyzed through fourier transform infrared spectroscopy. X-ray diffraction pattern shows that an average particle size of the synthesized nanoparticles are in the range of 40–24 nm. Field emission scanning electron microscopy and transmission electron microscopy confirm the formation Ag NPs in spherical shape. The photoluminescence study of the synthesized Ag NPs interprets the influence of C caudata leaf concentrations on emission behavior. Zeta potential measurement is carried out to determine the stability of synthesized Ag NPs. GC–MS analysis revealed that the C. caudata contained 11 compounds, such as Stigmasterol (24.14 %), Hexacosanoic acid, methyl ester (15.13 %) and 2-bromophenyl morpholine-4-carboxylate (11.71 %). The antibacterial activity of Ag NPs shows that these bio capped Ag NPs have higher inhibitory action for Escherichia coli, Klebsiella pheumoniea, Micrococcus flavus, Pseudomonas aeruginosa, Bacillus subtilis, Bacillus pumilus, Staphylococcus aureus.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-trimethylsilyl-substituded anililes

N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl)bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and ¹H, ¹³C, and ²⁹Si NMR spectroscopy.     

Synthesis of <Emphasis Type="Italic">o</Emphasis>(<Emphasis Type="Italic">m</Emphasis>)-carborane-containing azomethines

A method of preparative synthesis of o(m)-carborane-containing azomethines via the condensation of o(m)-carboranyl-C-methylene-4-formylbenzoates with aliphatic, cycloaliphatic, and aromatic amines was developed.     

Green Synthesis of Silver Nanoparticles Using an Aqueous Extract of <Emphasis Type="Italic">Monotheca buxifolia</Emphasis> (Flac.) Dcne

This study deals with the synthesis and physicochemical investigation of silver nanoparticles using an aqueous extract of Monotheca buxifolia (Flac.). On the treatment of aqueous solution of silver nitrate with the plant extract, silver nanoparticles were rapidly fabricated. The synthesized particles were characterized by using UV–visible spectrophotometry (UV), Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray (EDX) and Scanning electron microscopy (SEM). The formation of AgNPs was confirmed by noting the change in colour through visual observations as well as via UV–Vis spectroscopy. UV–Vis spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 440 nm. FTIR was used to identify the chemical composition of silver nanoparticles and Ag-capped plant extract. The presence of elemental silver was also confirmed through EDX analysis. The SEM analysis of the silver nanoparticles showed that they have a uniform spherical shape with an average size in the range of 40–78 nm. This green system showed better capping and stabilizing agent for the fine particles. Further, in vitro the antioxidant activity of Monotheca buxifolia (Flac.) and Ag-capped with the plant was also evaluated using FeCl₃/K₃Fe (CN)₆ essay.     

A Green Approach for the Synthesis of Silver Nanoparticles Using Root Extract of <Emphasis Type="Italic">Chelidonium majus:</Emphasis> Characterization and Antibacterial Evaluation

In this study, silver nanoparticles (Ag-NPs) have been synthesized using extract of Chelidonium majus root in aqueous solution at room temperature. The root extract was able to reduce Ag⁺ to Ag⁰ and stabilized the nanoparticles Different physico-chemical techniques including UV–Vis spectroscopy, transmission electron microscopy and powder X-ray diffraction (PXRD) were used for the characterization of the biosynthesized Ag-NPs obtained. The surface plasmon resonance band appeared at 431 nm is an evidence for formation of Ag-NPs. TEM imaging revealed that the synthesized Ag-NPs have an average diameter of around 15 nm and with spherical shape. Moreover the crystalline structure of synthesized nanoparticles was confirmed using XRD pattern. Furthermore antimicrobial activities of synthesized Ag-NPs were evaluated against Escherichia coli -ATCC 25922 and Pseudomonas aeruginosa ATCC 2785 bacteria strain.     

Synthesis of <Emphasis Type="Italic">N,N</Emphasis>-disubstituted (<Emphasis Type="Italic">Z</Emphasis>)-<Emphasis Type="Italic">O</Emphasis>-methylnicotinamide oximes

A number of (Z)-N,N-dialkyl- and (Z)-N-acyl-N-alkyl-O-methylnicotinamide oximes was synthesized. Their configuration was confirmed by the NOESY experiment. Evaluation of fungicidal activity of compounds obtained was performed.     

Copolymer of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-diallyl-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylammonium chloride with maleic acid as drug carrier

A copolymer of N,N-diallyl-N,N-dimethylammonium chloride with maleic acid of constant composition was prepared under the conditions of radical initiation. The possibility of the functionalization of the copolymer with drugs containing amino groups by polymer-analogous transformations was examined. Conditions were found for preparing conjugates of the copolymer with isoniazid. The structures and the quantitative compositions of the conjugates were determined by ¹³С NMR spectroscopy, and the possibility of preparing conjugates with controlled drug content was demonstrated.     

Molecular properties of the copolymers of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-diallyl-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylammonium chloride and maleic acid

The hydrodynamic and conformational properties of molecules of poly(N,N-diallyl-N,N-dimethylammonium chloride) and N,N-diallyl-N,N-dimethylammonium chloride-maleic acid copolymers of different compositions in solutions with various ionic-strength and pH values, as well as of the polyelectrolyte complex based on the copolymer with dodecyl sulfate anions in chloroform, are studied. For poly(N,N-diallyl-N,N-dimethylammonium chloride) molecules in a 1 M NaCl solution, the Kuhn segment length and the hydrodynamic diameter of the chain are estimated as A = 3.9 nm and d = 0.48 nm, respectively. In acidic solutions with pH 3.5, the copolymers demonstrate behavior typical for polyelectrolytes. In an alkaline solution with pH 13, when 1 M NaCl is added to the solution of the copolymer containing 29 mol % maleic acid units, there is an antipolyelectrolyte effect that manifests itself as an increase in the intrinsic viscosity of the copolymer and in the hydrodynamic radius of its molecules. It is found that an increase in the fraction of maleic acid units in the copolymer from 12 to 42 mol % brings about a reduction in the equilibrium rigidity of its macromolecules from 4.1 to 2.2 nm. The equilibrium rigidity of polyelectrolyte-complex molecules is higher than that of initial copolymer molecules owing to steric interactions arising between the aliphatic chains of dodecyl sulfate anions. In an electric field, the molecules of the complex are oriented owing to the induced dipole moment resulting from the displacement of dodecyl sulfate anions along the chain contour.     

Synthesis of 6-methyl-8<Emphasis Type="Italic">H</Emphasis>-dibenzo[<Emphasis Type="Italic">a</Emphasis>,<Emphasis Type="Italic">g</Emphasis>]quinolizin-8-imines <Emphasis Type="Italic">via Reissert</Emphasis> compounds

Alkylation of Reissert compounds derived from 3-methylisoquinolines with several 2-cyanobenzylbromides followed by hydrolytic cleavage provided the corresponding 1-benzyl-3-methylisoquinolines. Treatment of the latter with methylmagnesiumiodide caused cyclization to the title compounds rather than formation of 2-acetylbenzylisoquinolines.     

Synthesis of amino acid conjugates of glycyrrhizic acid using <Emphasis Type="Italic">N</Emphasis>-hydroxyphthalimide and <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>'-dicyclohexylcarbodiimide

Synthesis of amino acid conjugates of glycyrrhizic acid with the use of N-hydroxyphthalimide, N,N'-dicyclohexylcarbodiimide, and tert-butyl esters of L-amino acids (valine, isoleucine, phenylalanine, and methionine) was performed followed by deprotection with trifluoroacetic acid. The target amino acid conjugates were isolated by column chromatography on silica gel in 40–45% yield. The structure of the prepared compounds was confirmed by IR and ¹³C NMR spectroscopy.     

Green Synthesis of Silver Nanoparticles Using Water Extract from Galls of <Emphasis Type="Italic">Rhus Chinensis</Emphasis> and Its Antibacterial Activity

The green synthesis of silver nanoparticles (AgNPs) has been proposed as a simple, eco-friendly and cost effective alternative to chemical and physical methods. The Rhus chinensis plant is one of the well studied medicinal plant and its galls find excellent clinical and therapeutic applications. The present study reports the use of water extract from galls of R. chinensis as a reducing agent and formation of AgNPs from silver nitrate solution by a green synthesis route. The AgNPs formation was observed visually by color change and the absorbance peak at 450 nm was observed by UV–Visible spectrophotometer. The shape, size, and morphology of synthesized AgNPs were monitored by transmission electron microscopy and field-emission scanning electron microscopy. The face centered cubic structure of AgNPs was confirmed by X-ray diffraction pattern and element composition by energy dispersive X-ray analysis. The Fourier transform infrared spectroscopy spectrum revealed that the presence of components acts as a reducing and capping agent. The antibacterial activity was performed using the agar well diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration were determined by broth dilution and spread plate method respectively. Synthesized nanoparticles were spotted as triangular and hexagonal shape and the particle size was around 150 nm.     

Synthesis of <Emphasis Type="Italic">ortho</Emphasis>-carboranyl derivatives of (<Emphasis Type="Italic">S</Emphasis>)-asparagine and (<Emphasis Type="Italic">S</Emphasis>)-glutamine

(S)-Asparagine and (S)-glutamine ortho-carboranyl derivatives with free amino and carboxy groups in the α-position were synthesized. By an example of N ^γ-(1,2-dicarba-closo-dodecarboran-3-yl)-(S)-glutamine it was demonstrated that the developed synthetic approach carboranyl derivatives of amino acids allowed the preparation of optically pure isomers.     

Synthesis of Graft Copolyimides with Poly(<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylamino-2-ethyl methacrylate) Side Chains and Hybrid Nanocomposites with Silver Nanoparticles

The controlled radical polymerization of N,N-dimethylamino-2-ethyl methacrylate on polyimide multicenter macroinitiators under the action of the activating complex of Cu(I) with nitrogen-containing ligands is studied. The complex investigation of the kinetics of copolymerization and the molecular-mass characteristics of the products is performed. The polarity of a medium and the nature of the nitrogen-containing ligand used to prepare the catalytic complex considerably affect the rate of polymerization and the composition and molecular-mass characteristics of the product. Process conditions that enable the synthesis of regularly graft copolyimides with poly(N,N-dimethylamino-2-ethyl methacrylate) side chains are determined. It is shown that the products of grafting copolymerization may be used as a nanoreactor and a stabilizing agent for the template synthesis of composite structures containing silver nanoparticles in the absence of additional reducing agents.     

Synthesis of Novel <Emphasis Type="Italic">D</Emphasis>-<Emphasis Type="Italic">Seco</Emphasis>-Pregnenes

Summary. A new synthetic route was developed for the preparation of trans-3-hydroxy-16,17-seco-pregna-5,17(20)-dien-16-al, using Grob fragmentation as the key step. This seco-steroid contains a formyl group and an unsaturated side-chain in a sterically favourable position, and is therefore a promising starting material for the synthesis of novel condensed steroid heterocycles.Received March 22, 2003; accepted April 22, 2003 Published online September 25, 2003