Use of silver and silver salts is as old as human civilization but the fabrication of silver nanoparticles (Ag NPs) has only recently been recognized. They have been specifically used in agriculture and medicine as antibacterial, antifungal and antioxidants. It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus Candida albicans by binding Ag/Ag+ with the biomolecules present in the microbial cells. It has been suggested that Ag NPs produce reactive oxygen species and free radicals which cause apoptosis leading to cell death preventing their replication. Since Ag NPs are smaller than the microorganisms, they diffuse into cell and rupture the cell wall which has been shown from SEM and TEM images of the suspension containing nanoparticles and pathogens. It has also been shown that smaller nanoparticles are more toxic than the bigger ones. Ag NPs are also used in packaging to prevent damage of food products by pathogens. The toxicity of Ag NPs is dependent on the size, concentration, pH of the medium and exposure time to pathogens.

/pdf/a-review-on-biosynthesis-of-silver-nanoparticles-and-their-ivx9t7t18x.pdf

A review on biosynthesis of silver nanoparticles and their biocidal properties.

There is about 700,000 tonnes of dyes, of more than 10,000 types, that are used as coloring agents in industries, mainly for textile. The release of dyes in natural media is of concern due to their high persistence, toxicity and potential to the bioaccumulate in living organisms. In particular, the most commercialized and carcinogenic azo dyes, that pocess a benzidine function, needs urgent attention. Here, we review the current status of cationic and anionic dyes. We present dye removal techniques using nanoparticles through adsorption and degradation. Among dye removal techniques, adsorption was found the most efficient and cheap. For that, conventional adsorbents such as commercial activated carbon, chitosan and natural waste are often employed. We discuss the use of ZnO, TiO2 and Fe0 to remove dye pollution.

Degradation of hazardous organic dyes in water by nanomaterials

The current scenario of water resources shows the dominance of pollution caused by the draining of industrial effluents. The polluted waters have resulted in severe health and environmental hazards urging for a suitable alternative to resolve the implications. Various physical and chemical treatment steps currently in use for dye effluent treatment are more time consuming, cost-intensive, and less effective. Alternatively, nanoparticles due to their excellent surface properties and chemical reactivity have emerged as a better solution for dye removal and degradation. In this regard, the potential of silver nanoparticles in dye effluent treatment was greatly explored. Efforts were taken to unravel the kinetics and statistical optimization of the treatment conditions for the efficient removal of dyes. In addition, the role of silver nanocomposites has also experimented with colossal success. On the contrary, studies have also recognized the mechanisms of silver nanoparticle-mediated toxicity even at deficient concentrations and their deleterious biological effects when present in treated water. Hence, the fate of the silver nanoparticles released into the treated water and sludge, contaminating the soil, aquatic environment, and underground water is of significant concern. This review summarizes the current state of knowledge regarding the use of silver nanoparticles and silver-based nanocomposites in effluent treatment and comprehends the recent research on mitigation of silver nanoparticle-induced toxicity.

Silver nanoparticles in dye effluent treatment: A review on synthesis, treatment methods, mechanisms, photocatalytic degradation, toxic effects and mitigation of toxicity.

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed.

/pdf/green-synthesis-of-silver-nanoparticles-using-plant-extracts-257mul1vzf.pdf

Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature

In the field of nanotechnology, the development of reliable and eco-friendly methods for the synthesis of NPs is crucial. The conventional methods for the synthesis of NPs are costly, toxic, and not ecofriendly. To overcome these issues, natural sources such as plant, bacteria, fungi, and biopolymers have been used to synthesize AgNPs. These natural sources act as reducing and capping agents. The shape, size, and applications of AgNPs are prominently affected by the reaction parameters under which they are synthesized. Accessible distributed data on the synthesis of AgNPs include the impact of different parameters (temperature and pH), characterization techniques (DLS, UV-vis, FTIR, XRD, SEM, TEM and EDX), properties and their applications. This review paper discusses all the natural sources such as plants, bacteria, fungi, and biopolymers that have been used for the synthesis of AgNPs in the last ten years. AgNPs synthesized by green methods have found potential applications in a wide spectrum of areas including drug delivery, DNA analysis and gene therapy, cancer treatment, antimicrobial agents, biosensors, catalysis, SERS and magnetic resonance imaging (MRI). The current limitations and future prospects for the synthesis of inorganic nanoparticles by green methods are also discussed herein.

/pdf/facile-green-synthesis-and-applications-of-silver-3fykk7k4ju.pdf

Facile green synthesis and applications of silver nanoparticles: a state-of-the-art review

The present paper describes a less time-consuming and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) using an aqueous solution of silver nitrate and Amaranthus gangeticus Linn (Chinese spinach) leaf extract. The synthesized AgNPs which are to be used as an antimicrobial and Congo red dye is to be used as a toxic-degrading agent. AgNP was prepared by the reduction of silver nitrate solution by the leaf extract of Amarranthus Gangeticus Linn leaf extract in aqueous medium on heating for about 15 mins at 80 °C in presence of one drop 0.05 (M) NaOH. The size of the synthesized silver nanoparticles (AgNPs) using Amaranthus gangeticus Linn leaf extract and aqueous solution of silver nitrate (10−3 M) are formed at their stable condition within the range of 11–15 nm. AgNPs are obtained by this process within a couple of minutes of reaction without using reducing and stabilizing agents or harsh conditions. High-resolution transmission electron microscope (HR-TEM), selected area electron diffraction (SAED), ultraviolet-visible (UV-VIS) spectroscopy, and Fourier transform infrared spectroscopy (FTIR) are used to characterize the prepared AgNPs which show that the nanoparticles are globular in shape and polycrystalline. The synthesized silver nanoparticles showed inhibitory activity towards Gram positive, Gram negative bacteria and fungus and also showed good Congo red dye-degrading agents. The overall outcome of this study suggests that green synthesis AgNPs hold promise as a potent antibacterial and antifungal agent. The particles obtained were also found to degrade toxic Congo red dye.

/pdf/green-synthesis-of-silver-nanoparticles-with-antimicrobial-4f1zx22a5r.pdf

Green synthesis of silver nanoparticles with antimicrobial and azo dye (Congo red) degradation properties using Amaranthus gangeticus Linn leaf extract

The present investigation designed to evaluate the phytochemical and pharmacological activity of ethanolic extract of Solanum nigrum in experimental animal models. The ethanolic extract of S. nigrum was used in three different doses (100, 200 and 300 mg/kg bw) to evaluating anti-inflammatory and anti-convulsant activity by employing carrageenan paw edema and Supramaximal electric shock (MES) methods. Ethanolic extract of S. nigrum produced significant anti-inflammatory (P < 0.01) and anti-convulsant (P < 0.05) effect in dose dependent manner. The flavonoids present in the berries might be a responsible active constituent for this activity.

	 

	Key words: Solanum nigrum, anti-inflammatory activity, anti-convulsant, flavonoids

Phytochemical and pharmacological evaluation of Solanum nigrum Linn.

Organophosphate pesticides poisoning is a leading cause of morbidity and premature loss of life. Now those days it is very important factor in our life. Organophosphorus compound poisoning is a common cause of acute poisoning in India with high mortality, out of cause of death, an important are is respiratory failure. OPs cause toxicity after their absorption from skin, mucous membrane and respiratory tract following accidental exposures, or from gastrointestinal tract following suicidal ingestion. Organophosphorus compound are the chemical compound containing carbon-phosphorus bond. Poisoning with organophophorus compound may be i) Occupational ii) Accidental iii) Suicidal. The organophosphorus anti - chE agent are hydrolysed by two families of enzyme, carboxylesterases and paraoxonases, which are not inhibited by OP compounds. Discuss about the Pharmacokinetics, clinical feature of op compound poisoning The most widely used diagnostic tests for OP exposure are the estimation of plasma ( PchE) cholinesterase and red blood cells AchE activity. For treatment used Atropine as anti-cholinergic agent. activated charcoal can proven to be effective then it should be an extremely valuable theropy since if is widely available in the developing world. © 2011

Study of Various Poisoning: A Review

Allelopathic potential of a noxious weed on mung bean.

Objectives: Lawsone (1,4 naphthoquinone) is a non redox cycling compound that can be catalyzed by DT diaphorase (DTD) into 1,2,4-trihydroxynaphthalene (THN), which can generate reactive oxygen species by auto oxidation. The purpose of this study was to evaluate the toxicity of the phytomarker 1,4 naphthoquinone and its metabolite THN by using the molecular docking program AutoDock 4. Methods: The 3D structure of ligands such as hydrogen peroxide (H2O2), nitric oxide synthase (NOS), catalase (CAT), glutathione (GSH), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH) and nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) were drawn using hyperchem drawing tools and minimizing the energy of all pdb files with the help of hyperchem by MM + followed by a semi-empirical (PM3) method. The docking process was studied with ligand molecules to identify suitable dockings at protein binding sites through annealing and genetic simulation algorithms. The program auto dock tools (ADT) was released as an extension suite to the python molecular viewer used to prepare proteins and ligands. Grids centered on active sites were obtained with spacings of 54 × 55 × 56, and a grid spacing of 0.503 was calculated. Comparisons of Global and Local Search Methods in Drug Docking were adopted to determine parameters; a maximum number of 250,000 energy evaluations, a maximum number of generations of 27,000, and mutation and crossover rates of 0.02 and 0.8 were used. The number of docking runs was set to 10. Results: Lawsone and THN can be considered to efficiently bind with NOS, CAT, GSH, GR, G6PDH and NADPH, which has been confirmed through hydrogen bond affinity with the respective amino acids. Conclusion: Naphthoquinone derivatives of lawsone, which can be metabolized into THN by a catalyst DTD, were examined. Lawsone and THN were found to be identically potent molecules for their affinities for selected proteins.

Computational Optimization of Bioanalytical Parameters for the Evaluation of the Toxicity of the Phytomarker 1,4 Napthoquinone and its Metabolite 1,2,4-trihydroxynapththalene

Parthapratim Maiti

Papers

Green synthesis of silver nanoparticles with antimicrobial and azo dye (Congo red) degradation properties using Amaranthus gangeticus Linn leaf extract

Phytochemical and pharmacological evaluation of Solanum nigrum Linn.

Study of Various Poisoning: A Review

Allelopathic potential of a noxious weed on mung bean.

Computational Optimization of Bioanalytical Parameters for the Evaluation of the Toxicity of the Phytomarker 1,4 Napthoquinone and its Metabolite 1,2,4-trihydroxynapththalene