Biofabrication of calcium phosphate nanoparticles using the plant Mimusops elengi

Nanoparticles are now widely applied in products. The synthesis of nanomaterials using biological materials is an emerging field, notably for medical applications because biologically derived compounds can be safe. For instance, calcium phosphate is a natural biomineral that possesses an excellent biocompatibility due to its chemical similarity to human hard tissue such as bone and teeth. Here, we synthesized calcium phosphate nanoparticles by using bark extract of Spanish cherry (Mimusops elengi). Calcium phosphate nanoparticles showed an absorbance at 275 nm by UV–visible analysis and particle size of 25 nm by nanoparticle tracking and analysis. Fourier transform infrared spectroscopy revealed the presence of aromatic amines as a capping and reducing agent. Transmission electron microscopy showed the presence of polydispersed spherical nanoparticles with an average size of 50 nm. Measurements of zeta potential revealed the stability of the synthesized calcium phosphate nanoparticles. These particles demonstrated antibacterial activity against Streptococcus mutans, Staphylococcus aureus and Escherichia coli. We conclude that the synthesis of calcium phosphate nanoparticles by using a M. elengi is easy, eco-friendly and scalable.     

High reduction of 4-nitrophenol using reduced graphene oxide/Ag synthesized with tyrosine

There is a demand for the development of environmental friendly methods for the synthesis of graphene composites. Reduced graphene oxide/silver (RGO/Ag) nanocomposites are very good catalysts. Here, we propose a simple, green method for the synthesis of RGO/Ag nanocomposite using the amino acid tyrosine as bioreductant and stabilizing agent. RGO/Ag nanocomposite was characterized by using various analytical techniques and studied for its catalytic degradation of 4-nitrophenol. Results of attenuated total reflectance Fourier transform infrared spectroscopy and Zeta potential at ?55 mV reveal the surface capping of tyrosine onto the reduced graphene oxide nanosheets. RGO/Ag nanocomposites show excellent catalytic reduction of 4-nitrophenol with NaBH₄, when compared to actual individual silver nanoparticles.     

Large-scale synthesis and antibacterial activity of fungal-derived silver nanoparticles

There is a demand for environmentally friendly processes to synthesize nanoparticles. Here, we synthesized silver nanoparticles using encapsulated biomass beads of Phoma exigua var. exigua. Nanoparticles were characterized by nanoparticle tracking and analysis (NTA), Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and zeta potential. Results of NTA show that nanoparticle size was homogenous. Concerning nanoparticle stability, zeta potential decreased with batch number. Silver nanoparticles exhibited an antibacterial activity against Escherichia coli and Staphylococcus aureus. Overall, the encapsulation of fungal biomass by calcium alginate for the batch synthesis of silver nanoparticles was easy, cost-effective, eco-friendly and suitable for the large-scale synthesis of silver nanoparticles. We have also demonstrated the reusability of the fungal biomass during biosynthesis of silver nanoparticles using the sodium alginate encapsulation method.     

In vitro microbiological evaluation of novel 2-oxo-2H-chromene-3-carbaldehyde containing 1,3,4-thiadiazole moiety

4-(5-(Methylthio)-1,3,4-thiadiazol-2-ylamino)-2-oxo-2H-chromene-3-carbaldehyde (3) and 4-(5-(ethylthio)-1,3,4-thiadiazol-2-ylamino)-2-oxo-2H-chromene-3-carbaldehyde (4) were prepared. The structures of the newly synthesized compounds were characterized by infrared (IR), nuclear magnetic resonance (NMR) spectral data and elemental analysis. The synthesized compounds were screened in vitro for their antibacterial activities. The synthesized compounds demonstrated moderate antimicrobial activity.     

Microbiological evaluation of 4-(6-chloro-7H-purin-8-ylamino)-3-nitro-chromen-2-one with a comparison to antibacterial activity of standard drugs

Nucleophilic substitution of 4-chloro-3-nitro-2-oxo-2H-chromen-2-one 3 by 6-chloro-7H-purin-2-ylamine (a), yielded the corresponding 4-(6-chloro-7H-purin-8-ylamino)-3-nitro-chromen-2-one 4. The chemical structure of synthesized compound was characterized using IR and NMR spectra, and elemental analyses. The purified synthesized compound 4 was tested at concentrations 1, 3, 5 mg/ml for its antibacterial activity against three bacterial cultures: Staphylococcus aureus, Escherichia coli, and Bacillus cereus. The antibacterial activity of synthesized compound was compared to antibacterial activity of standard antibiotics cephalexine and streptomycin.     

Synthesis of Li-doped bismuth oxide nanoplates,Co nanoparticles modification,and good photocatalytic activity toward organic pollutants

Abstract

Lithium-doped bismuth oxide nanoplates with the thickness of 50–150?nm and tetragonal bismuth oxide, monoclinic lithium bismuthate phases have been synthesized via a simple hydrothermal process using lithium acetate and sodium bismuthate as the raw materials. Cobalt nanoparticles modified lithium-doped bismuth oxide nanoplates hybrids were obtained by an in situ photo-deposition route. The cobalt nanoparticles-modified nanoplates hybrids display significantly enhanced photocatalytic activity toward gentian violet compared with the nanoplates. Gentian violet solution can be totally degraded by the hybrids within 60?min under ultraviolet–visible light irradiation. The superior photocatalytic activity of the cobalt nanoparticles modified nanoplates hybrids originates from the superior charge transfer capacity and the energy band structure of the hybrids. The excellent photocatalytic performance makes the cobalt nanoparticles modified nanoplates hybrids a promising candidate as the photocatalyst for wastewater treatment.     

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

● All 1,4-naphthoquinone hybrids exhibited significant antimicrobial activity. ● Presence of a hydroxyl group on aromatic B-ring of juglone was crucial for activity. ● Juglone can cause DNA damage by producing ROS and downregulation of RecA. ● Juglone has the potential to become a disinfectant. The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic, thereby increasing the demands for the development of disinfectants based on natural products, with low health risks and low aquatic toxicity. In the present study, a few natural naphthoquinones and their derivatives bearing the 1,4-naphthoquinone skeleton were synthesized, and their antibacterial activity against selected bacterial strains was evaluated. In vitro antibacterial activities of the compounds were investigated against Escherichia coli and Staphylococcus aureus. Under the minimum inhibitory concentration (MIC) of ≤ 0.125 μmol/L for juglone (1a), 5,8-dimethoxy-1,4-naphthoquinone (1f), and 7-methyl-5-acetoxy-1,4-naphthoquinone (3c), a strong antibacterial activity against S. aureus was observed. All 1,4-naphthoquinone derivatives exhibited a strong antibacterial activity, with MIC values ranging between 15.625 and 500 μmol/L and EC₅₀ values ranging between 10.56 and 248.42 μmol/L. Most of the synthesized compounds exhibited strong antibacterial activities against S. aureus. Among these compounds, juglone (1a) showed the strongest antibacterial activity. The results from mechanistic investigations indicated that juglone, a natural naphthoquinone, caused cell death by inducing reactive oxygen species production in bacterial cells, leading to DNA damage. In addition, juglone could reduce the self-repair ability of bacterial DNA by inhibiting RecA expression. In addition to having a potent antibacterial activity, juglone exhibited low cytotoxicity in cell-based investigations. In conclusion, juglone is a strong antibacterial agent with low toxicity, indicating that its application as a bactericidal agent may be associated with low health risks and aquatic toxicity.     

Microwave-assisted synthesized zinc nanoparticles attenuate cisplatin-induced testicular toxicity in mice

Abstract

The purpose of this study was to investigate the protective effects of zinc nanoparticles against cisplatin-induced testicular toxicity in mice. Zinc nanoparticles were produced by microwave-assisted synthesis using Lavandula vera extract as reducing agent. Single doses of cisplatin (7?mg/kg, intraperitoneally) and ZnSO₄ (10?mg/kg, orally), and various doses of zinc nanoparticles (10???50?mg/kg, orally) and vitamin E (100?mg/kg, interaperitoneally) were administered. The protective role of zinc nanoparticles was determined biochemically and histologically. Gradual reduction in malondialdehyde levels and elevation in glutathione levels and in the activities of superoxide dismutase and catalase upon administration of zinc nanoparticles were observed. The pathology of mice treated with cisplatin/vitamin E and cisplatin/zinc nanoparticles were apparently equal, but vitamin E treatment was more effective in lowering oxidative stress markers than zinc nanoparticles. These findings suggest that co-administration of zinc nanoparticles with cisplatin could prevent adverse effects on the male reproductive system via their potential antioxidant properties.     

Efficient oxidation of sulfides into sulfoxides catalyzed by a chitosan–Schiff base complex of Cu(II) supported on supramagnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles

Sulfoxides are versatile synthetic intermediates for the preparation of biological products. Therefore, there is a need for efficient methods to oxidize sulfides into sulfoxides. Such oxidation may be catalyzed by magnetic nanocatalysts due to their good stability, easy synthesis, high surface area, low toxicity and easy separation by magnetic forces. Here we prepared a nanocatalyst by immobilization of the chitosan–Schiff base complex on supramagnetic Fe₃O₄ nanoparticles. The chitosan–Schiff base complex has been previously prepared by functionalization of chitosan with 5-bromosalicylaldehyde and metalation with copper(II) acetate. The catalyst was characterized by Fourier transform infrared, powder X-ray diffraction, transmission electron microscope, scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermogravimetric analysis. Results show that the Fe₃O₄ nanoparticles and nanocatalyst were spherical in shape with an average size of 20 nm. Upon the covalently anchoring of chitosan–Schiff base Cu complex on the magnetic Fe₃O₄ nanoparticles, the average size increased to 60 nm. The prepared Fe₃O₄–chitosan–Schiff base Cu complex catalyzed very efficiently the oxidation of sulfides to sulfoxides with 100 % selectivity in all cases under green reaction conditions and excellent yields. Additionally, ease of recovery and reusability up to four cycles without noticeable loss of catalytic activity make the present protocol beneficial from industrial and environmental viewpoint.     

Synthesis of some novel (2-oxo-3-(arylimino) indolin-1-yl)-N-aryl acetamides and evaluation as antimicrobial agents

A series of sixteen 2-oxo-3-(arylimino) indolin-1-yl)-N-aryl acetamide derivatives were synthesized, characterized by physical and spectral data (IR, ¹H nuclear magnetic resonance (NMR), and mass spectrometry), and evaluated for their antibacterial and antifungal activities against various pathogenic microorganisms. Some of the synthesized compounds showed promising antibacterial and antifungal activities, the best being 2-(3-(4-chlorophenylimino)-2-oxoindolin-1-yl)-N-(3-methoxyphenyl) acetamide.     

Synthesis of SnO2 quantum dots mediated by Camellia sinensis shoots for degradation of thiamethoxam

Abstract

A novel method of synthesis of tin dioxide quantum dots employing Camellia sinensis shoots as reducing agent and stabilizer is presented. The quantum dots were characterized by UV spectroscopy, X-Ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The crystalline tin dioxide quantum dots with an average size of 4.3?nm were of flake like morphology capped by phenolic compounds of Camellia sinensis. The quantum dots were employed for the photocatalytic degradation of thiamethoxam resulting in 57% degradation within 45 mins.     

Effects of Zn and ZnO nanoparticles and Zn2+ on soil enzyme activity and bioaccumulation of Zn in Cucumis sativus

The increased production and commercial use of nanoparticles (NPs), combined with a lack of regulation regarding their disposal, may result in the unwanted introduction of NPs to soils. In this study, the toxicity on soil enzyme activity and growth of Cucumis sativus treated with Zn or ZnO NPs was evaluated in pot soils. Specifically, C. sativus was cultivated in soils treated with Zn NPs, ZnO NPs or Zn²⁺ for eight weeks, after which the treatment effects on biomass and bioaccumulation were evaluated. In addition, the treatment effects on soil dehydrogenase, β -glucosidase and acid phosphatase were investigated. Soil enzyme activities were influenced by all treatments, with an especially large decrease in dehydrogenase activity in response to Zn²⁺ treatment. Biomass and root length also decreased in response to Zn²⁺ treatment. Finally, the Zn contents of C. sativus were much lower in the Zn NP and ZnO NP treatment groups than in the Zn²⁺ treatment group. Therefore, toxicity on soil microbial activity may have a greater influence than phytotoxicity due to immobilisation and aggregation of NPs in the soil.     

Synthesis and antibacterial activity of a Fe3O4–AgCl nanocomposite against Escherichia coli

In this investigation, Fe₃O₄ magnetic nanoparticles (MNPs) were prepared by the alkalinization of an aqueous medium containing ferrous sulfate and ferric chloride. In the next step, a Fe₃O₄–AgCl magnetic nanocomposite was fabricated by the drop-by-drop addition of silver nitrate solution into a NaCl solution containing Fe₃O₄ MNPs. All prepared nanoparticles were characterized by transition electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Both particle types varied in size from 2.5 to 20?nm, with an average size of 7.5?nm for Fe₃O₄ MNPs and 12.5?nm for Fe₃O₄–AgCl nanocomposites. The antibacterial effect of the Fe₃O₄ MNPs and fabricated Fe₃O₄–AgCl nanocomposites against Escherichia coli (ATCC 35218) were investigated by conventional serial agar dilution method using the Müller–Hinton Agar medium. The minimum inhibitory concentration was 4?mg?mL^?1 for Fe₃O₄ MNPs and 2?mg?mL^?1 for the Fe₃O₄–AgCl magnetic nanocomposites. Time-kill course assays showed that the Fe₃O₄–AgCl magnetic nanocomposites successfully killed all inoculated bacterial cells during an exposure time of 60?min. The antibacterial activity of recycled Fe₃O₄–AgCl magnetic nanocomposites over four 60?min cycles of antibacterial treatment was further tested against E. coli by the colony-forming unit (CFU) method. The antibacterial efficiency of the nanocomposites was constant over two cycles of antibacterial testing.     

Combined sorptional–photocatalytic remediation of dyes by polyaniline Zr(IV) selenotungstophosphate nanocomposite

A polyaniline Zr(IV) selenotungstophosphate nanocomposite was prepared via sol-gel method and characterized by thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The combined sorptional–photocatalytic activity of the nanocomposite for degradation of methylene blue and malachite green was investigated and was found to be more efficient than separate adsorption in the dark followed by photocatalysis. The dyes were degraded in 3 h by 96% and 89% by the combined process, as compared to 86% and 72% by the two-step process in 5 h. The nanocomposite material showed antimicrobial activity against Staphylococcus aureus and Escherichia coli.     

Responses of oxidative stress,genotoxicity and immunotoxicity as biomarkers in Theba pisana snails dietary exposed to silver nanoparticles

Silver nanoparticles (AgNPs) are now being of a great interest by ecotoxicological researchers. Their potential hazards to humans and other non-target organisms had led to crucial concerns. In this research, white radish leaf extract was used for the green synthesis of AgNPs. UV–Vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been utilised to characterise the biosynthesised AgNPs. Furthermore, the present study aimed to investigate the ecotoxicological effects of 1?mM biosynthesised AgNPs on the land snail, Theba pisana after two weeks of exposure and one week recovery with respect to oxidative stress parameters; lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT) and glutathione-S-transferase (GST), cytogenetic parameters; DNA content and micronucleus test, as well as immunological parameters; cell death, phagocytosis, lysosomal membrane stability (LMS), lectins, superoxide anion (O₂^?) generation, phenoloxidase (PO), peroxidase (POD) and haemocyanin (Hc) were examined. AgNPs have been biosynthesised successfully; the UV–vis spectrum exhibited a single and broad absorption band located between 375 and 415?nm, TEM image shows AgNPs formed were nearly spherical in shape with a mean size of 2.18–19.87?nm and the crystalline nature of nanoparticles was confirmed by XRD. After two weeks exposure, the result showed that AgNPs significantly increased LPO level as well as CAT and GST activities, cell death, cell abnormalities and Hc level, whereas, significant decline was found in DNA and GSH contents, phagocytic activity, LMS, lectins, O₂^? generation, POD and PO activities compared to the controls. After a week of recovery, most of the tested biomarkers in AgNP-exposed snails did not completely return to the control levels. The multiple measured parameters could be effectively used as sensitive biomarkers in the risk assessment of contaminants in the terrestrial ecosystem.     

Synthesis and in vitro biological evaluation of 3, 4-annelated coumarin-pyrimido-pyrimidine systems

3,4-Annelated coumarin-pyrimido-pyrimidine systems (7-imino-8-mercapto-7H-5-oxa-7a,9,12-triaza-benzo[a]anthracen-6-one 2 and 8-hydroxy-7-imino-10-methyl-7H-5-oxa-7a,9,12-triaza-benzo[a]anthracen-6-one 3) were synthesized by the action of 4-amino-2-mercapto-pyrimidine, 2-amino-4-hydroxy-6-methylpyrimidine, respectively, on 4-chlorocoumarin-3-carbonitrile 1. The synthesized compounds were examined for in vitro antibacterial activity against 4 bacterial cultures: Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, and Aeromonas Salmonicida. The antibacterial activity of synthesized compounds 2 and 3 was compared to antibacterial activity of novobiocin as a standard drug.     

Evaluation of environmental stress by comet assay on freshwater snail Lymnea luteola L. exposed to titanium dioxide nanoparticles

The use of aquatic organisms to monitor for contamination is well-established. Therefore, this study was designed to assess the adverse effects of titanium dioxide nanoparticles (TiO₂NP) in freshwater snail Lymnea luteola L. (L. luteola). For TiO₂NPs ecotoxicity tests, snails were exposed for seven days. A dose and time-response relationship was observed for TiO₂NP-induced genotoxicity. Induction of oxidative stress in digestive gland was observed by a decrease in glutathione and gluthathions-S-transferase levels accompanied by elevated malondialdehyde levels at TiO₂NP (9 and 28 µg/mL). Superoxide dismutase activities were markedly reduced at TiO₂NP (9 and 28 µg/mL) at days 1 and 3, but not at day 7. Catalase activities were decreased at days 1 and 3 but increased at higher concentration of TiO₂NP at day 7. DNA fragmentation occurring in L. luteola due to ecotoxic impact TiO₂NP was further substantiated by alkaline single-cell gel electrophoresis assay and expressed in terms of percent tail DNA and olive tail moment. The results indicate that the interaction of these TiO₂NP with snail influences the toxicity, which is mediated by oxidative stress in a dose- and time-dependent manner. The measurement of DNA integrity in L. luteola thus provides an early warning signal of contamination of the aquatic ecosystem by TiO₂NP. Data suggest the freshwater snail L. luteola is a potential biomonitor organism.     

Antibacterial,antiviral and antioxidant activities of aerial part extracts of Peganum harmala L. grown in Tunisia

Ethyl acetate, chloroform, butanol, and methanol extracts from the aerial part of Peganum harmala were tested for antibacterial, antioxidant, and antiviral activities. The antibacterial activity was evaluated by the determination of minimum inhibitory concentration (MIC) using the solid medium technique. Oxacillin, amoxicillin, ticarcillin, cefotaxim, and amphotericin were used as control agents. The antiviral activity was evaluated against human cytomegalovirus (HCMV) strain AD-169 (ATCC Ref. VR 538) and Coxsackie B virus type 3 (CoxB-3) using a cytopathic effect (CPE) reduction assay. The antioxidant activity was evaluated using two tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging and ammonium thiocyanate methods. Among tested extracts; the chloroform extract displayed a higher antibacterial activity against Gram-positive than Gram-negative bacteria. The butanol extract demonstrated the highest antioxidant activity. The methanol extract showed significant antiviral activity against CoxB-3 virus. The chloroform extract may be an important source of bactericidal compounds against Gram-positive bacteria.     

Synthesis and evaluation of antioxidant activities of some indole-2,3-dione derivatives and analogs

In the present study, a series of novel Schiff bases of isatin were synthesized by condensation of imesatin with different aromatic aldehydes. The imesatins were synthesized by reaction of isatin with p-phenylenediamine. The chemical structures of the synthesized compounds were confirmed by means of IR, 1H-NMR, 13C-NMR, mass spectroscopy, and elemental analysis. These compounds were screened for antioxidant activity by DPPH, nitric oxide and hydrogen peroxide radical scavenging activity. In all the methods, the compound 3-(4-(3,4,5-trimethoxy benzylideneamino)phenylimino) indoline-2-one (5d) showed highest antioxidant activity because of the presence of electron donating groups and the compound 3-(4-(4-nitrobenzylideneamino)phenylimino) indoline-2-one (5f) showed the least activity because of the presence of an electron withdrawing group.     

Nanoparticles influence on expression of cell cycle related genes in Drosophila: a microarray-based toxicogenomics study

Relatively little is known regarding the interaction of nanoscale objects with dynamic complex biological systems. Microarray-based toxicogenomics studies may serve as a suitable technique to explore the genome wide effects of nanoparticles on any organism through a single experiment. The influence of nanoporous aluminosilicate nanoparticles (NP), citrate-capped gold NP, lipophilic silica NP, BSA-capped silver NP, and lipophilic zinc oxide NP were studied on 75 cell cycle-related genes of adult Drosophila melanogaster. Microarray experiments were conducted after the flies were fed with NP-mixed media for 15 days. Data showed that silver, zinc oxide, and alumino silicate NP predominantly perturbed cell cycle genes, whereas gold and silica NP exerted the least influence on these genes.