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1.
Phytochemistry ; 159: 20-29, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30562679

RESUMO

Rauvolfia tetraphylla L. (family Apocynaceae), often referred to as the wild snakeroot plant, is an important medicinal plant and produces a number of indole alkaloids in its seeds and roots. The plant is often used as a substitute for Ravuolfia serpentine (L.) Benth. ex Kurz known commonly as the Indian snakeroot plant or sarphagandha in the preparation of Ayurvedic formulations for a range of diseases including hypertension. In this study, we examine the spatial localization of the various indole alkaloids in developing fruits and plants of R. tetraphylla using desorption electrospray ionization mass spectrometry imaging (DESI-MSI). A semi-quantitative analysis of the various indole alkaloids was performed using UPLC-ESI/MS. DESI-MS images showed that the distribution of ajmalcine, yohimbine, demethyl serpentine and mitoridine are largely localized in the fruit coat while that for ajmaline is restricted to mesocarp of the fruit. At a whole plant level, the ESI-MS intensities of many of the ions were highest in the roots and lesser in the shoot region. Within the root tissue, except sarpagine and ajmalcine, all other indole alkaloids occurred in the epidermal and cortex tissues. In leaves, only serpentine, ajmalcine, reserpiline and yohimbine were present. Serpentine was restricted to the petiolar region of leaves. Principal component analysis based on the presence of the indole alkaloids, clearly separated the four tissues (stem, leaves, root and fruits) into distinct clusters. In summary, the DESI-MSI results indicated a clear tissue localization of the various indole alkaloids, in fruits, leaves and roots of R. tetraphylla. While it is not clear of how such localization is attained, we discuss the possible pathways of indole alkaloid biosynthesis and translocation during fruit and seedling development in R. tetraphylla. We also briefly discuss the functional significance of the spatial patterns in distribution of metabolites.


Assuntos
Cromatografia Líquida/métodos , Componentes Aéreos da Planta/metabolismo , Raízes de Plantas/metabolismo , Rauwolfia/metabolismo , Alcaloides de Triptamina e Secologanina/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos , Análise de Componente Principal , Espectrometria de Massas em Tandem/métodos
2.
Anal Chem ; 88(11): 5710-7, 2016 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-27159150

RESUMO

In this paper, desorption electrospray ionization mass spectrometry (DESI MS)-based molecular analysis and imprint imaging using electrospun nylon-6 nanofiber mats are demonstrated for various analytical contexts. Uniform mats of varying thicknesses composed of ∼200 nm diameter fibers were prepared using needleless electrospinning. Analytical applications requiring rapid understanding of the analytes in single drops, dyes, inks, and/or plant extracts incorporated directly into the nanofibers are discussed with illustrations. The possibility to imprint patterns made of printing inks, plant parts (such as petals, leaves, and slices of rhizomes), and fungal growth on fruits with their faithful reproductions on the nanofiber mats is illustrated with suitable examples. Metabolites were identified by tandem mass spectrometry data available in the literature and in databases. The results highlight the significance of electrospun nanofiber mats as smart surfaces to capture diverse classes of compounds for rapid detection or to imprint imaging under ambient conditions. Large surface area, appropriate chemical functionalities exposed, and easiness of desorption due to weaker interactions of the analyte species are the specific advantages of nanofibers for this application.

3.
J Hazard Mater ; 297: 183-90, 2015 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-25956648

RESUMO

The present work report the unusual uranium uptake by foodstuff, especially those rich in carbohydrates like rice when they are cooked in water, contaminated with uranium. The major staple diet in South Asia, rice, was chosen to study its interaction with UO2(2+), the active uranium species in water, using inductively coupled plasma mass spectrometry. Highest uptake limit was checked by cooking rice at very high uranium concentration and it was found to be good scavenger of uranium. To gain insight into the mechanism of uptake, direct interaction of UO2(2+) with monosaccharides was also studied, using electrospray ionization mass spectrometry taking mannose as a model. The studies have been done with dissolved uranium salt, uranyl nitrate hexahydrate (UO2(NO3)2·6H2O), as well as the leachate of a stable oxide of uranium, UO2(s), both of which exist as UO2(2+) in water. Among the eight different rice varieties investigated, Karnataka Ponni showed the maximum uranium uptake whereas unpolished Basmati rice showed the minimum. Interaction with other foodstuffs (potato, carrot, peas, kidney beans and lentils) with and without NaCl affected the extent of chemical interaction but was not consistent with the carbohydrate content. Uranium interaction with D-mannose monitored through ESI-MS, under optimized instrumental parameters, identified the peaks corresponding to uranyl adduct with mannose monomer, dimer and trimer and the species were confirmed by MS/MS studies. The product ion mass spectra showed peaks illustrating water loss from the parent ion as the collision energy was increased, an evidence for the strong interaction of uranium with mannose. This study would constitute the essential background for understanding interaction of uranium with various foods. Extension of this work would involve identification of foodstuff as green heavy metal scavengers.


Assuntos
Culinária , Contaminação de Alimentos/análise , Oryza , Urânio/análise , Água/química , Carboidratos/química , Cromatografia Líquida , Glucose/química , Manose/química , Microscopia Eletrônica de Varredura , Nitratos/química , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Infravermelho , Espectrometria de Massas em Tandem , Temperatura , Raios Ultravioleta , Compostos de Urânio/química , Poluentes Químicos da Água/análise
4.
J Biomed Nanotechnol ; 10(3): 405-14, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24730236

RESUMO

Photothermal therapy using (Near Infrared) NIR region of EM spectrum is a fast emerging technology for cancer therapy. Different types of nanoparticles may be used for enhancing the treatment. Though the treatment protocols are developed based on experience driven estimated temperature increase in the tissue, it is not really known what spatiotemporal thermal behavior in the tissue is. In this work, this thermal behavior of tissue models is investigated with and without using nanoparticles. An increased temperature inside tissue compared to surface is observed which is counter intuitive from the present state of knowledge. It is shown from fiber level microstructure that this increased temperature leads to enhanced damage at the deeper parts of biomaterials. Nanoparticles can be utilized to control this temperature increase spatially. A multiple scattering based physical model is proposed to explain this counterintuitive temperature rise inside tissue. The results show promising future for better understanding and standardizing the protocols for photothermal therapy.


Assuntos
Hipertermia Induzida/normas , Raios Infravermelhos/uso terapêutico , Fototerapia/normas , Temperatura , Ágar/química , Ágar/efeitos da radiação , Ágar/ultraestrutura , Animais , Bovinos , Colágeno/química , Colágeno/efeitos da radiação , Colágeno/ultraestrutura , Simulação por Computador , Géis , Hipertermia Induzida/efeitos adversos , Hipertermia Induzida/métodos , Fototerapia/efeitos adversos , Fototerapia/métodos
5.
Sci Rep ; 2: 679, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22997553

RESUMO

Thalidomide, a sedative drug given to pregnant women, unfortunately caused limb deformities in thousands of babies. Recently the drug was revived because of its therapeutic potential; however the search is still ongoing for an antidote against thalidomide induced limb deformities. In the current study we found that nitric oxide (NO) rescues thalidomide affected chick (Gallus gallus) and zebrafish (Danio rerio) embryos. This study confirms that NO reduced the number of thalidomide mediated limb deformities by 94% and 80% in chick and zebrafish embryos respectively. NO prevents limb deformities by promoting angiogenesis, reducing oxidative stress and inactivating caspase-3 dependent apoptosis. We conclude that NO secures angiogenesis in the thalidomide treated embryos to protect them from deformities.


Assuntos
Indutores da Angiogênese/farmacologia , Anormalidades Musculoesqueléticas/induzido quimicamente , Doadores de Óxido Nítrico/farmacologia , Espermina/análogos & derivados , Teratogênicos/toxicidade , Talidomida/toxicidade , Indutores da Angiogênese/uso terapêutico , Animais , Aorta/efeitos dos fármacos , Aorta/patologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Catalase/fisiologia , Embrião de Galinha , Avaliação Pré-Clínica de Medicamentos , Desenvolvimento Embrionário/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/fisiologia , Feminino , Técnicas In Vitro , Masculino , Anormalidades Musculoesqueléticas/prevenção & controle , Neovascularização Fisiológica/efeitos dos fármacos , Doadores de Óxido Nítrico/uso terapêutico , Óxido Nítrico Sintase Tipo III/biossíntese , Espécies Reativas de Oxigênio/metabolismo , Espermina/farmacologia , Espermina/uso terapêutico , Peixe-Zebra , Proteínas de Peixe-Zebra/metabolismo
6.
Langmuir ; 28(5): 2671-9, 2012 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-22239644

RESUMO

Application of nanoparticles (NPs) in environmental remediation such as water purification requires a detailed understanding of the mechanistic aspects of the interaction between the species involved. Here, an attempt was made to understand the chemistry of noble metal nanoparticle-pesticide interaction, as these nanosystems are being used extensively for water purification. Our model pesticide, chlorpyrifos (CP), belonging to the organophosphorothioate group, is shown to decompose to 3,5,6-trichloro-2-pyridinol (TCP) and diethyl thiophosphate at room temperature over Ag and Au NPs, in supported and unsupported forms. The degradation products were characterized by absorption spectroscopy and electrospray ionization mass spectrometry (ESI MS). These were further confirmed by ESI tandem mass spectrometry. The interaction of CP with NP surfaces was investigated using transmission electron microscopy, energy dispersive analysis of X-rays, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS reveals no change in the oxidation state of silver after the degradation of CP. It is proposed that the degradation of CP proceeds through the formation of AgNP-S surface complex, which is confirmed by Raman spectroscopy. In this complex, the P-O bond cleaves to yield a stable aromatic species, TCP. The rate of degradation of CP increases with increase of temperature and pH. Complete degradation of 10 mL of 2 ppm CP solution is achieved in 3 h using 100 mg of supported Ag@citrate NPs on neutral alumina at room temperature at a loading of ∼0.5 wt %. The effect of alumina and monolayer protection of NPs on the degradation of CP is also investigated. The rate of degradation of CP by Ag NPs is greater than that of Au NPs. The results have implications to the application of noble metal NPs for drinking water purification, as pesticide contamination is prevalent in many parts of the world. Study shows that supported Ag and Au NPs may be employed in sustainable environmental remediation, as they can be used at room temperature in aqueous solutions without the use of additional stimulus such as UV light.


Assuntos
Clorpirifos/química , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Óxido de Alumínio/química , Estrutura Molecular , Tamanho da Partícula , Soluções , Propriedades de Superfície , Água/química
7.
Langmuir ; 27(13): 8134-43, 2011 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-21667956

RESUMO

We report the chemical interactions of unsupported and alumina-supported Ag(7) and Ag(8) clusters protected with MSA (mercaptosuccinic acid) with heavy metal ions Hg(II), Cd(II), and Pb(II) in water at different concentrations. The investigation was carried out to determine the feasibility of this interesting new class of materials called quantum clusters for water purification. These systems were studied using various spectroscopic and microscopic techniques such as ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, zeta potential measurements, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy and in detail by X-ray photoelectron spectroscopy. We observed that the metal ions interact with both the silver atoms of the clusters and the functional groups of the capping agent (MSA). The mercuric ions were reduced to metallic mercury by both supported and unsupported clusters, due to the feasibility of the redox reaction, whereas no reduction was observed for Cd(II) and Pb(II). As a result of the interaction, the luminescence of the cluster is lost which can be used to sense Hg(II). At lower concentrations, the metal ions were chemically bonded to the carboxylate groups of MSA. Absence of reduction of Hg(II) at lower concentration is due to the chemical affinity of the ligands and the lower silver content per cluster compared to the number of carboxylate groups.


Assuntos
Metais Pesados/química , Prata/química , Óxido de Alumínio/química , Íons/química , Nanopartículas/química , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Tamanho da Partícula , Propriedades de Superfície , Tiomalatos/química , Água/química
8.
J Hazard Mater ; 189(1-2): 450-7, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21398028

RESUMO

In this work, we describe the use of silver nanoparticles of 9 ± 2 and 20 ± 5 nm core diameter, protected by mercaptosuccinic acid (MSA) and supported on activated alumina for the removal of mercuric ions present in contaminated waters, at room temperature (28 ± 1 °C). These two nanoparticle samples were prepared by using two Ag:MSA ratios 1:6 and 1:3, respectively, during synthesis and were loaded on alumina at 0.5 and 0.3% by weight. The mechanism of interaction of silver nanoparticles with Hg(2+) ions was studied using various analytical techniques such as ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), inductively coupled plasma-optical emission spectrometry (ICP-OES), energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Interactions of the metal ion with the metal core, the surface head group and the monolayer functionality were investigated. A high removal ability of 0.8 g of mercury per gram of Ag@MSA was achieved in the case of 1:6 Ag@MSA. These two materials show better uptake capacity of Hg(2+) in the pH range of 5-6. The ease of synthesis of the nanomaterial by wet chemistry, capability to load on suitable substrates to create stable materials and affordable cost will make it possible to use this approach in field applications, especially for the treatment of Hg(2+) contaminated waters.


Assuntos
Mercúrio/isolamento & purificação , Nanopartículas Metálicas/química , Prata/química , Adsorção , Óxido de Alumínio , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/isolamento & purificação
9.
J Ethnopharmacol ; 125(1): 178-81, 2009 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-19539020

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Calotropis gigantea R.Br. (Asclepiadaceae) is a perennial undershrub found chiefly in wastelands throughout India. It has been reported as a traditional folkloric medicine for a variety of alignments. The plant Calotropis gigantea is also used in some parts of India for wound healing in combination with other plants. However there are no scientific reports on wound healing activity of the plant Calotropis gigantea R.Br. AIM OF THE STUDY: To investigate the effects of Calotropis gigantea root bark on wound healing activity in rats by excision, incision and dead space wound healing models in rats. METHODOLOGY: Wistar albino rats of either sex weighing between 180 and 200 g were topically treated with extract formulated in ointment by using simple ointment BP as base. 5% (w/w) ointment was applied once daily in excision wound model. Calotropis gigantea ethanolic extract was given orally at a dose of 100, 200, and 400 mg/kg in incision and dead space wound healing models. Rats of standard groups were treated with 5% Povidone iodine ointment topically. The percentage wound closure, epithelization time, hydroxyproline content and scar area on complete epithelization were measured. RESULTS: Topical application of Calotropis gigantea in excision wound model increased the percentage of wound contraction. Scar area and epithelization time were decreased. In incision wound and dead space wound breaking strength of wounds and hydroxyproline was increased. CONCLUSION: Calotropis gigantea accelerated wound healing in rats and thus supports its traditional use.


Assuntos
Calotropis/química , Casca de Planta/química , Extratos Vegetais/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Feminino , Masculino , Ratos , Ratos Wistar
10.
J Nanosci Nanotechnol ; 7(6): 1871-7, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17654957

RESUMO

The nanoparticles of gold and silver in solution state and supported over activated alumina are effective systems for the quantitative removal of chlorpyrifos and malathion, two common pesticides found in surface waters of developing nations, from water. In the solution phase, these pesticides adsorb onto the nanoparticles' surfaces and upon interaction for a long time, the nanoparticles with adsorbed pesticides precipitate. In contrast, complete removal of these pesticides occurs when contaminated water is passed over nanoparticles supported on alumina. A prototype of an on-line filter was made using a column of activated alumina powder loaded with silver nanoparticles and the device was used for pesticide removal for extended periods. We believe that the method has great technological potential in drinking water purification, especially using silver nanoparticles.


Assuntos
Óxido de Alumínio/química , Clorpirifos/isolamento & purificação , Malation/isolamento & purificação , Nanoestruturas/química , Poluentes da Água/isolamento & purificação , Purificação da Água/métodos , Água/química , Adsorção , Clorpirifos/química , Cristalização/métodos , Substâncias Macromoleculares/química , Malation/química , Teste de Materiais , Conformação Molecular , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Tamanho da Partícula , Propriedades de Superfície
11.
Langmuir ; 22(24): 10125-9, 2006 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-17107009

RESUMO

The antibacterial activity of ciprofloxacin-encapsulated silica nanoshells synthesized from gold@silica core-shell nanoparticles has been investigated. The minimum inhibitory concentration of the material was found using the agar dilution method, and it showed better antibacterial activity compared to free ciprofloxacin in the case of Escherichia coli DH5, whereas the same activity was found for Lactococcus lactis MG 1363. Hydrophobicity measurements carried out in an octanol-water mixture suggested that ciprofloxacin@SiO2 is distributed almost equally in the aqueous and nonaqueous phases. The kinetics of the uptake of ciprofloxacin@SiO2 was compared with that of free ciprofloxacin. Fluorescence imaging studies carried out using fluorescein isothiocyanate@SiO2 showed that the nanoshells enter the bacterial cell. The uptake of silica shells has been probed by transmission electron microscopy also.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Ciprofloxacina/química , Ciprofloxacina/farmacologia , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli/metabolismo , Fluoresceína-5-Isotiocianato/farmacologia , Cinética , Lactococcus lactis/metabolismo , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Octanóis/química , Quinolonas/química , Raios Ultravioleta , Água/química
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