Effect of the carbon coating in Fe-C-TiO(2) photocatalyst on phenol decomposition under UV irradiation via photo-Fenton process.

PubMed

Tryba, Beata; Morawski, Antoni W; Inagaki, Michio; Toyoda, Masahiro

2006-08-01

Fe-C-TiO(2) photocatalysts which contained the residue carbon (0.2-3.3 mass%) were prepared from a mixture of TiO(2) and FeC(2)O(4) through the heating at 673-1173 K in Ar. These photocatalysts did not show a high adsorption of phenol, but they were active in photo-Fenton reactions during decomposition of phenol under UV irradiation with addition of H(2)O(2). It was proved that Fe(2+) governed the photoactivity of Fe-C-TiO(2) photocatalysts, it decreased with heat-treatment temperature above 773 K. For comparison, Fe-TiO(2) photocatalyst was prepared by heating TiO(2) and FeC(2)O(4) at 823 K in air for 3h. Phenol decomposition was going much slower on Fe-TiO(2) photocatalyst in comparison with Fe-C-TiO(2), of which mechanism was different, on the former phenol was decomposed by the radical reaction, on the latter through a complex reaction with iron and intermediates of phenol decomposition. Therefore carbon-coating TiO(2) was found to be advantageous for mounting iron and its application for the phenol decomposition via photo-Fenton process.

Effect of humic acids on intestinal viscosity, leaky gut and ammonia excretion in a 24 h feed restriction model to induce intestinal permeability in broiler chickens

USDA-ARS?s Scientific Manuscript database

Humic acids (HA) are produced by biodegradation of organic matter that involves physical, chemical and microbiological processes, hence, HA are a complex mixture of many different acids containing carboxyl and phenolate groups. The purpose of this study was to evaluate the effect of HA on intestina...

Integrated phospholipidomics and transcriptomics analysis of Saccharomyces cerevisiae with enhanced tolerance to a mixture of acetic acid, furfural, and phenol

USDA-ARS?s Scientific Manuscript database

A mixture of acetic acid, furfural and phenol (AFP), three representative lignocellulose derived inhibitors, significantly inhibited the growth and bioethanol production of Saccharomyces cerevisiae. In order to uncover mechanisms behind the enhanced tolerance of an inhibitor-tolerant S.cerevisiae s...

A core-shell column approach to a comprehensive high-performance liquid chromatography phenolic analysis of Vitis vinifera L. and interspecific hybrid grape juices, wines, and other matrices following either solid phase extraction or direct injection.

PubMed

Manns, David C; Mansfield, Anna Katharine

2012-08-17

Four high-throughput reverse-phase chromatographic protocols utilizing two different core-shell column chemistries have been developed to analyze the phenolic profiles of complex matrices, specifically targeting juices and wines produced from interspecific hybrid grape cultivars. Following pre-fractionation via solid-phase extraction or direct injection, individual protocols were designed to resolve, identify and quantify specific chemical classes of compounds including non-anthocyanin monomeric phenolics, condensed tannins following acid hydrolysis, and anthocyanins. Detection levels ranging from 1.2 ppb to 27.5 ppb, analyte %RSDs ranging from 0.04 to 0.38, and linear ranges of quantitation approaching five orders of magnitude were achieved using conventional HPLC instrumentation. Using C(18) column chemistry, the non-anthocyanin monomeric protocol effectively separated a set of 16 relevant phenolic compounds comprised flavan-3-ols, hydroxycinnamic acids, and flavonols in under 14 min. The same column was used to develop a 15-min protocol for hydrolyzed condensed tannin analysis. Two anthocyanin protocols are presented, one utilizing the same C(18) column, best suited for anthocyanidin and monoglucoside analysis, the other utilizing a pentafluorophenyl chemistry optimized to effectively separate complex mixtures of coexisting mono- and diglucoside anthocyanins. These protocols and column chemistries have been used initially to explore a wide variety of complex phenolic matrices, including red and white juices and wines produced from Vitis vinifera and interspecific hybrid grape cultivars, juices, teas, and plant extracts. Each protocol displayed robust matrix responses as written, yet are flexible enough to be easily modified to suit specifically tailored analytical requirements. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous biodegradation of a phenol and 3,4-dimethylphenol mixture under denitrifying conditions.

PubMed

Puig-Grajales, L; Rodríguez-Nava, O; Razo-Flores, E

2003-01-01

Denitrification is a feasible alternative for the treatment of phenolic bearing-wastewaters. The aim of this study was to evaluate the biodegradability of phenolic compounds, as the only carbon and energy source in batch and continuous experiments, using nitrate as a final electron acceptor. Experiments in a continuous upward anaerobic sludge bed reactor demonstrated the possibility of biodegrading a mixture of phenol and 3,4-dimethylphenol at organic loads of 251.6 and 39.5 mg/L-d, respectively, at a COD/NO3(-)-N ratio of 2.57. A nitrogen production efficiency of 86% was obtained according to the nitrate consumption. GC-MS analyses demonstrated that m-cresol was an intermediate of 3,4-dimethylphenol degradation in batch conditions, and had an inhibitory effect on phenol degradation.

Analysis of Protein-Phenolic Compound Modifications Using Electrochemistry Coupled to Mass Spectrometry.

PubMed

Kallinich, Constanze; Schefer, Simone; Rohn, Sascha

2018-01-29

In the last decade, electrochemical oxidation coupled with mass spectrometry has been successfully used for the analysis of metabolic studies. The application focused in this study was to investigate the redox potential of different phenolic compounds such as the very prominent chlorogenic acid. Further, EC/ESI-MS was used as preparation technique for analyzing adduct formation between electrochemically oxidized phenolic compounds and food proteins, e.g., alpha-lactalbumin or peptides derived from a tryptic digestion. In the first step of this approach, two reactant solutions are combined and mixed: one contains the solution of the digested protein, and the other contains the phenolic compound of interest, which was, prior to the mixing process, electrochemically transformed to several oxidation products using a boron-doped diamond working electrode. As a result, a Michael-type addition led to covalent binding of the activated phenolic compounds to reactive protein/peptide side chains. In a follow-up approach, the reaction mix was further separated chromatographically and finally detected using ESI-HRMS. Compound-specific, electrochemical oxidation of phenolic acids was performed successfully, and various oxidation and reaction products with proteins/peptides were observed. Further optimization of the reaction (conditions) is required, as well as structural elucidation concerning the final adducts, which can be phenolic compound oligomers, but even more interestingly, quite complex mixtures of proteins and oxidation products.

An integrated high resolution mass spectrometric and informatics approach for the rapid identification of phenolics in plant extract

USDA-ARS?s Scientific Manuscript database

An integrated approach based on high resolution MS analysis (orbitrap), database (db) searching and MS/MS fragmentation prediction for the rapid identification of plant phenols is reported. The approach was firstly validated by using a mixture of phenolic standards (phenolic acids, flavones, flavono...

Solar-based detoxification of phenol and p-nitrophenol by sequential TiO2 photocatalysis and photosynthetically aerated biological treatment.

PubMed

Essam, Tamer; Aly Amin, Magdy; El Tayeb, Ossama; Mattiasson, Bo; Guieysse, Benoit

2007-04-01

Simulated solar UV/TiO(2) photocatalysis was efficient to detoxify a mixture of 100 mgphenoll(-1) and 50 mgp-nitrophenol (PNP) l(-1) and allow the subsequent biodegradation of the remaining pollutants and their photocatalytic products under photosynthetic aeration with Chlorella vulgaris. Photocatalytic degradation of phenol and PNP was well described by pseudo-first order kinetics (r(2)>0.98) with removal rate constants of 1.9x10(-4) and 2.8x10(-4)min(-1), respectively, when the pollutants were provided together and 5.7x10(-4) and 9.7x10(-4)min(-1), respectively, when they were provided individually. Photocatalytic pre-treatment of the mixture during 60 h removed 50+/-1% and 62+/-2% of the phenol and PNP initially present but only 11+/-3% of the initial COD. Hydroquinone, nitrate and catechol were identified as PNP photocatalytic products and catechol and hydroquinone as phenol photocatalytic products. Subsequent biological treatment of the pre-treated samples removed the remaining contaminants and their photocatalytic products as well as 81-83% of the initial COD, allowing complete detoxification of the mixture to C. vulgaris. Similar detoxification efficiencies were recorded after biological treatment of the irradiated mixture with activated sludge microflora or with an acclimated consortia composed of a phenol-degrading Alcaligenes sp. and a PNP-degrading Arthrobacter sp., although the acclimated strains biodegraded the remaining pollutants faster. Biological treatment of the non-irradiated mixture was inefficient due to C. vulgaris inhibition.

Liquid-liquid and solid-phase extractions of phenols from virgin olive oil and their separation by chromatographic and electrophoretic methods.

PubMed

Bendini, Alessandra; Bonoli, Matteo; Cerretani, Lorenzo; Biguzzi, Barbara; Lercker, Giovanni; Toschi, Tullia Gallina

2003-01-24

The high oxidative stability of virgin olive oil is related to its high monounsaturated/polyunsaturated ratio and to the presence of antioxidant compounds, such as tocopherols and phenols. In this paper, the isolation of phenolic compounds from virgin olive oil, by different methods, was tested and discussed. Particularly liquid-liquid and solid-phase extraction methods were compared, assaying, for the latter, three stationary phases (C8, C18 and Diol) and several elution mixtures. Quantification of phenolic and o-diphenolic substances in the extracts was performed by the traditional Folin-Ciocalteau method and the sodium molybdate reaction, respectively. Furthermore, the quantification of phenolic compounds in the extracts and in a standard mixture was carried out both with diode array and mass spectrometric detection and capillary zone electrophoresis.

Physicochemical characterisation of β-carotene emulsion stabilised by covalent complexes of α-lactalbumin with (-)-epigallocatechin gallate or chlorogenic acid.

PubMed

Wang, Xiaoya; Liu, Fuguo; Liu, Lei; Wei, Zihao; Yuan, Fang; Gao, Yanxiang

2015-04-15

In this study the impact of covalent complexes of α-lactalbumin (α-La) with (-)-epigallocatechin gallate (EGCG) or chlorogenic acid (CA) was investigated on the physicochemical properties of β-carotene oil-in-water emulsions. EGCG, or CA, was covalently linked to α-La at pH 8.0, as evidenced by increased total phenolic content and declined fluorescence intensity. Compared with those stabilised by α-La alone and α-La-CA or EGCG mixture, the emulsion stabilised by the α-La-EGCG covalent complex exhibited the least changes in particle size and transmission profiles, using a novel centrifugal sedimentation technique, indicating an improvement in the physical stability. The least degradation of β-carotene occurred in the emulsion stabilised with the α-La-EGCG covalent complex when stored at 25 °C. These results implied that protein-polyphenol covalent complexes were able to enhance the physical stability of β-carotene emulsion and inhibit the degradation of β-carotene in oil-in-water emulsion, and the effect was influenced by the types of the phenolic compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

Treesearch

Hui Pan; Todd F. Shupe; Chung-Yun Hse

2008-01-01

Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three-necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac-type liquefied wood/phenol/...

Differential Degradation of Nonylphenol Isomers by Sphingomonas xenophaga Bayram

PubMed Central

Gabriel, Frédéric L. P.; Giger, Walter; Guenther, Klaus; Kohler, Hans-Peter E.

2005-01-01

Sphingomonas xenophaga Bayram, isolated from the activated sludge of a municipal wastewater treatment plant, was able to utilize 4-(1-ethyl-1,4-dimethylpentyl)phenol, one of the main isomers of technical nonylphenol mixtures, as a sole carbon and energy source. The isolate degraded 1 mg of 4-(1-ethyl-1,4-dimethylpentyl)phenol/ml in minimal medium within 1 week. Growth experiments with five nonylphenol isomers showed that the three isomers with quaternary benzylic carbon atoms [(1,1,2,4-tetramethylpentyl)phenol, 4-(1-ethyl-1,4-dimethylpentyl)phenol, and 4-(1,1-dimethylheptyl)phenol] served as growth substrates, whereas the isomers containing one or two hydrogen atoms in the benzylic position [4-(1-methyloctyl)phenol and 4-n-nonylphenol] did not. However, when the isomers were incubated as a mixture, all were degraded to a certain degree. Differential degradation was clearly evident, as isomers with more highly branched alkyl side chains were degraded much faster than the others. Furthermore, the C9 alcohols 2,3,5-trimethylhexan-2-ol, 3,6-dimethylheptan-3-ol, and 2-methyloctan-2-ol, derived from the three nonylphenol isomers with quaternary benzylic carbon atoms, were detected in the culture fluid by gas chromatography-mass spectrometry, but no analogous metabolites could be found originating from 4-(1-methyloctyl)phenol and 4-n-nonylphenol. We propose that 4-(1-methyloctyl)phenol and 4-n-nonylphenol were cometabolically transformed in the growth experiments with the mixture but that, unlike the other isomers, they did not participate in the reactions leading to the detachment of the alkyl moiety. This hypothesis was corroborated by the observed accumulation in the culture fluid of an as yet unidentified metabolite derived from 4-(1-methyloctyl)phenol. PMID:15746308

Organic matter characteristics in boreal forest soils under stands of silver birch, Norway spruce, and Norway spruce with a mixture of silver birch

NASA Astrophysics Data System (ADS)

Smolander, A.; Kitunen, V.

2012-04-01

The aim was to study how tree species and a tree species mixture affect microbial C and N transformations and two major plant secondary compound groups, terpenes and phenolic compounds in soil. The study site was a tree-species experiment in middle-eastern part of Finland containing plots of 43-year-old silver birch, Norway spruce and Norway spruce with a mixture of silver birch (22 and 37 % birch of the total stem number). Soil was podzol and humus type mor. Samples were taken from the organic layer. C and N in the microbial biomass, rates of C mineralization (CO2 evolution), net N mineralization and nitrification, and concentrations of total water-soluble phenolic compounds, condensed tannins and different kind of terpenes were measured. Amounts of C and N in the microbial biomass and the rates of C mineralization and net N mineralization were all lower under spruce than birch, and particularly net N mineralization was stimulated by birch mixture. Concentrations of total water-soluble phenolic compounds were on a similar level, irrespective of tree species. However, there were less low-molecular-weight phenolics and more high-molecular-weight phenolics under spruce than birch. Concentrations of condensed tannins and both sesqui- and diterpenes were all higher under spruce than birch but the concentrations of triterpenes were similar in all soils. The difference between tree species was greatest with monoterpenes which were measured from both organic layer and soil atmosphere: high concentrations under spruce and negligible under birch. Birch mixture tended to decrease the concentrations of condensed tannins and mono-, sesqui- and diterpenes.

Olfactory and behavioural responses of tabanid horseflies to octenol, phenols and aged horse urine.

PubMed

Baldacchino, F; Manon, S; Puech, L; Buatois, B; Dormont, L; Jay-Robert, P

2014-06-01

Electrophysiological and behavioural responses of females of two tabanid species, Tabanus bromius L. and Atylotus quadrifarius (Loew) (Diptera: Tabanidae), to ammonia, octenol (1-octen-3-ol), phenols and aged horse urine were compared. Electroantennogram (EAG) responses in both species to octenol, 4-methylphenol (4MP), 3-propylphenol (3PP) and a phenol mixture (4MP and 3PP at a ratio of 16 : 1) increased in a dose-dependent fashion. The most effective stimulus was 4MP and synergism between the two phenols may exist. Aged horse urine also elicited strong EAG responses in both species. Using gas chromatography-mass spectrometry (GC-MS) analysis, we identified 29 compounds in horse urine, which included, in particular, ketones, fatty alcohols and phenols, among which 4MP was the most abundant component (~ 80%). Trapping experiments were carried out using Nzi traps baited with various odours. Octenol and the phenol mixture in combination with ammonia increased catches of tabanids by 1.8-2.8 times relative to ammonia alone. Aged horse urine increased catches of T. bromius and A. quadrifarius by 2.2 and 4.1 times, respectively. The high attractiveness of aged horse urine, especially for A. quadrifarius, is not likely to derive from 4MP alone, but from the mixture of various active compounds used in host location. © 2013 The Royal Entomological Society.

Inhibition of the acetoclastic methanogenic activity by phenol and alkyl phenols.

PubMed

Olguin-Lora, P; Puig-Grajales, L; Razo-Flores, E

2003-08-01

Chemical and petrochemical industries are important sources of aromatic pollutants. Petrochemical processes like caustic washing of middle distillates produce the spent caustic liquors highly concentrated in phenol and alkyl phenols. The anaerobic technology is considered a feasible strategy for petrochemical wastewater pre-treatment although high concentrations of phenol could limit its efficiency. The goal of this work was to determine the toxicity of both selected alkyl phenols and a synthetic "spent-caustic phenols mixture" on the acetoclastic Specific Methanogenic Activity (SMA) of unadapted and phenol-adapted granular sludge. Alkyl phenols were responsible for 50% (IC50) and 100% (IC100) inhibition of the SMA at concentrations ranging from 1.6 to 5.0 mM and from 4.1 to 27.5 mM, respectively, for un-adapted granular sludge. In the case of phenol-adapted granular sludge, the inhibitory concentrations ranged from 1.7 to 14.9 mM and from 4.0 to 83.0 for IC50 and IC100, respectively, highlighting the impact of sludge acclimation. The inhibition produced by 2-ethylphenol was more acute compared to phenol and was not reduced by the phenol acclimation process. The IC50 and IC100 values obtained for the synthetic "spent-caustic phenols mixture" were 9.5 mM and 88.4 mM, respectively. The inhibitory concentrations of phenol compounds were closely correlated with compound apolarity (log P), indicating that the lipophilic character of the tested compounds was responsible for their methanogenic toxicity. An inhibition model is confirmed to estimate the IC50 and IC100.

Environmental Fate of a Complex Mixture, Creosote, in Two Species of Fish

DTIC Science & Technology

1994-04-01

tissues, such as edible flesh and ovary [23, 71]. English sole hepatocytes do not form significant amounts of sulfate conjugates of BaP phenols (Figures...Gladys Yanagida (technical support), Dr. Mary Arkoosh for the gift of rainbow trout, Mr. Herb Sanborn for collection of English sole and Eagle Harbor...Research, 265, 223-236. 2. Giddings, J.M., Herbes , S.E., and Gehrs, C.W., (1985) Coal liquefaction products. Environmental Science & Technology, 19, 14-18

Wettability of southern pine veneer by phenol formaldehyde wood adhesives

Treesearch

Chung-Yun Hse

1972-01-01

Wettability of southern pine veneers was judged by measuring the contact angles made by 36 phenol formaldehyde resins. Formulation of the resins was by factorial design, the molar ratios of sodium hydroxide to phenol being 0.4, 0.7, and 1.0, the levels of resin solids content in the reaction mixture 37, 40, and 43 percent, and the molar ratios of formaldehyde to phenol...

Wettability of southern pine veneer by phenol formaldehyde wood adhesives

Treesearch

C. -Y. Hse

1972-01-01

Wettabillty of southern pine veneers was judged by measuring the contact angles made by 36 phenol formaldehyde resins. Formulation of the resins was by factorial design. the molar ratios of sodium hydroxide to phenol being 0.4, 0.7, and 1.0, the levels of resin solids content in the reaction mixture 37, 40, and 43 percent, and the molar ratios of formaldehyde to phenol...

Organic carbon aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, R.W.

1998-04-28

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes {<=}1000 {angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

Organic carbon aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, Richard W.

1998-04-28

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes .ltoreq.1000 .ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, Richard W.

1995-01-01

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes.ltoreq.1000.ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, R.W.

1995-12-19

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes{<=}1000{angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, Richard W.

1996-01-01

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes .ltoreq.1000.ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

Phenolic and physicochemical stability of a functional beverage powder mixture during storage: effect of the microencapsulant inulin and food ingredients.

PubMed

de Beer, Dalene; Pauck, Claire E; Aucamp, Marique; Liebenberg, Wilna; Stieger, Nicole; van der Rijst, Marieta; Joubert, Elizabeth

2018-06-01

The need for a convenience herbal iced tea product with reduced kilojoules merited investigation of the shelf-life of powder mixtures containing a green Cyclopia subternata Vogel (honeybush) extract with proven blood glucose-lowering activity and alternative sweetener mixture. Prior to long-term storage testing, the wettability of powder mixtures containing food ingredients and the compatibility of their components were confirmed using the static sessile drop method and isothermal microcalorimetry, respectively. The powders packed in semi-sealed containers remained stable during storage at 25 °C/60% relative humidity (RH) for 6 months, except for small losses of specific phenolic compounds, namely mangiferin, isomangiferin, 3-β-d-glucopyranosyliriflophenone, vicenin-2 and 3',5'-di-β-d-glucopyranosylphloretin, especially when both citric acid and ascorbic acid were present. These acids drastically increased the degradation of phenolic compounds under accelerated storage conditions (40 °C/75% RH). Accelerated storage also caused changes in the appearance of powders and the colour of the reconstituted beverage solutions. Increased moisture content and a w of the powders, as well as moisture released due to dehydration of citric acid monohydrate, contributed to these changes. A low-kilojoule honeybush iced tea powder mixture will retain its functional phenolic compounds and physicochemical properties during shelf-life storage at 25 °C for 6 months. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The principal phenolic and alcoholic components of wine protect human lymphocytes against hydrogen peroxide- and ionizing radiation-induced DNA damage in vitro.

PubMed

Greenrod, William; Fenech, Michael

2003-03-01

We have tested the hypothesis that the alcoholic and phenolic components of wine are protective against the DNA-damaging and cytotoxic effects of hydrogen peroxide and gamma-radiation in vitro. The components of wine tested were ethanol, glycerol, a mixture of the phenolic compounds catechin and caffeic acid and tartaric acid, all at concentrations that were 2.5 or 10.0% of the concentration in a typical Australian white wine (Riesling). These components were tested individually or combined as a mixture and compared to a white wine stripped of polyphenols, as well as a Hanks balanced salt solution control, which was the diluent for the wine components. The effect of the components was tested in lymphocytes, using the cytokinesis-block micronucleus assay, after 30 min incubation in plasma or whole blood for the hydrogen peroxide or gamma-radiation challenge, respectively. The results obtained showed that ethanol, glycerol, the catechin-caffeic acid mixture, the mixture of all components and the stripped white wine significantly reduced the DNA-damaging effects of hydrogen peroxide and gamma-radiation (P = 0.043-0.001, ANOVA). The strongest protective effect against DNA damage by gamma-irradiation was observed for the catechin-caffeic acid mixture and the mixture of all components (30 and 32% reduction, respectively). These two treatments as well as ethanol produced the strongest protective effects against DNA damage by hydrogen peroxide (24, 25 and 18%, respectively). The protection provided by the mixture did not account for the expected additive protective effects of the individual components. Ethanol was the only component that significantly increased baseline DNA damage rate, however, this effect was negated in the mixture. In conclusion, our results suggest that the main phenolic and alcoholic components of wine can reduce the DNA-damaging effects of two important oxidants, i.e. hydrogen peroxide and ionizing radiation, in this physiologically relevant in vitro system.

Alkylation of phenol by alcohols in the presence of aluminum phenolate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koshchii, V.A.; Kozlikovskii, Ya.B.; Matyusha, A.A.

1988-12-20

The reaction of phenol with alcohols in the presence of aluminum phenolate leads to a mixture of 2- and 4-alkylphenols, of which the former predominate in the case of benzyl, tert-butyl, and cyclohexyl alcohols, and the latter in the case of dimethylphenyl- and diphenylmethylcarbinols. Only triphenyl(4-hydroxyphenyl)-methane is formed during the alkylation of phenol by triphenylcarbinol. In individual experiments the formation of small amounts of alkyl phenyl ethers and 2,6-dialkylphenols was observed.

Field solar degradation of pesticides and emerging water contaminants mediated by polymer films containing titanium and iron oxide with synergistic heterogeneous photocatalytic activity at neutral pH.

PubMed

Mazille, F; Schoettl, T; Klamerth, N; Malato, S; Pulgarin, C

2010-05-01

Photocatalytic degradation of phenol, nalidixic acid, mixture of pesticides, and another of emerging contaminants in water was mediated by TiO(2) and iron oxide immobilized on functionalized polyvinyl fluoride films (PVF(f)-TiO(2)-Fe oxide) in a compound parabolic collector (CPC) solar photoreactor. During degradation, little iron leaching (<0.2mgL(-1)) was observed. Phenol was efficiently degraded and mineralized at operational pH<5 and nalidixic acid degradation was complete even at pH 7, but mineralization stopped at 35%. Pesticide mixture was slowly degraded (50%) after 150min of irradiation. Degradation of the emergent contaminant mixture was successful for eight compounds and less efficient for six other compounds. The significant reactivity differences between tested compounds were assigned to the differences in structure namely that the presence of complexing or chelating groups enhanced the rates. PVF(f)-TiO(2)-Fe oxide photoactivity gradually increased during 20 days of experiments. X-ray photoelectron spectroscopy (XPS) measurements revealed significant changes on the catalyst surface. These analyses confirm that during photocatalysis mediated by PVF(f)-TiO(2)-Fe oxide, some iron leaching led to enlargement of the TiO(2) surface exposed to light, increasing its synergy with iron oxides and leading to enhanced pollutant degradation.

Characterisation of phenolics in Flor-Essence--a compound herbal product and its contributing herbs.

PubMed

Saleem, Ammar; Walshe-Roussel, Brendan; Harris, Cory; Asim, Muhammad; Tamayo, Carmen; Sit, Summer; Arnason, John Thor

2009-01-01

Commercially available herbal mixture FE, a proprietary natural health product manufactured by Flora Manufacturing and Distributing Ltd (Flora), is a unique North American traditional herbal product. FE is a chemically complex mixture of eight herbs and has not been subjected to phytochemical analysis. To develop analytical methods to undertake detailed phytochemical analyses of FE, and its eight contributing herbs, including burdock (Arctium lappa L.), sheep sorrel (Rumex acetosella L.), Turkish rhubarb (Rheum palmatum L.), slippery elm Muhl. (Ulmus rubra), watercress (Nasturtium officinale R. Br.), red clover (Trifolium pratense L.), blessed thistle (Cnicus benedictus L.) and kelp (Laminaria digitata Lmx.). The identification was undertaken by a combination of reversed phase high performance liquid chromatography-diode array detection-atmospheric pressure chemical ionisation-mass selective detection (RP-HPLC-DAD-APCI-MSD) analysis and phenolics metabolomic library matching. New separation methods facilitated the identification of 43 markers in the individual herbs which constitute FE. Sixteen markers could be identified in FE originating from four contributing herbs including four caffeoyl quinic acids, three dicaffeoyl quinic acids and two caffeic acid derivatives from A. lappa, luteolin-7-O-glucoside, luteolin, five apigenin glycosides and apigenin from R. acetocella and N. officinale and sissostrin from T. pretense. A validated method for quantitative determination of three markers is reported with good intraday, interday and interoperator repeatability using a reliable alcohol based extraction technique. FE and its contributing herbs predominantly contain phenolics. This methodology can be applied to further develop full-scale validation of this product.

Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

DOEpatents

Pekala, R.W.

1996-09-17

The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes {<=}1,000{angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1,050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

Analysis of phenolic compounds in different parts of pomegranate (Punica granatum) fruit by HPLC-PDA-ESI/MS and evaluation of their antioxidant activity: application to different Italian varieties.

PubMed

Russo, Marina; Fanali, Chiara; Tripodo, Giusy; Dugo, Paola; Muleo, Rosario; Dugo, Laura; De Gara, Laura; Mondello, Luigi

2018-06-01

The analysis of pomegranate phenolic compounds belonging to different classes in different fruit parts was performed by high-performance liquid chromatography coupled with photodiode array and mass spectrometry detection. Two different separation methods were optimized for the analysis of anthocyanins and hydrolyzable tannins along with phenolic acids and flavonoids. Two C 18 columns, core-shell and fully porous particle stationary phases, were used. The parameters for separation of phenolic compounds were optimized considering chromatographic resolution and analysis time. Thirty-five phenolic compounds were found, and 28 of them were tentatively identified as belonging to four different phenolic compound classes; namely, anthocyanins, phenolic acids, hydrolyzable tannins, and flavonoids. Quantitative analysis was performed with a mixture of nine phenolic compounds belonging to phenolic compound classes representative of pomegranate. The method was then fully validated in terms of retention time precision, expressed as the relative standard deviation, limit of detection, limit of quantification, and linearity range. Phenolic compounds were analyzed directly in pomegranate juice, and after solvent extraction with a mixture of water and methanol with a small percentage of acid in peel and pulp samples. The accuracy of the extraction method was also assessed, and satisfactory values were obtained. Finally, the method was used to study identified analytes in pomegranate juice, peel, and pulp of six different Italian varieties and one international variety. Differences in phenolic compound profiles among the different pomegranate parts were observed. Pomegranate peel samples showed a high concentration of phenolic compounds, ellagitannins being the most abundant ones, with respect to pulp and juice samples for each variety. With the same samples, total phenols and antioxidant activity were evaluated through colorimetric assays, and the results were correlated among them.

Antioxidant/prooxidant effects of dietary non-flavonoid phenols on the Cu2+-induced oxidation of human low-density lipoprotein (LDL).

PubMed

Briante, Raffaella; Febbraio, Ferdinando; Nucci, Roberto

2004-11-01

A central role in the oxidative development of atherosclerotic lesions has been ascribed to the peroxidation of plasma low-density lipoprotein (LDL). Dietary supplementation with virgin olive oils increases the total plasma antioxidant status and the resistance of low-density lipoprotein to ex vivo oxidation. We have studied the effects of some dietary non-flavonoid phenols from Olea europaea L., both in purified form or in complex mixtures obtained by biotransformation of olive leaf extracts, on the LDL oxidation induced by Cu2+ ions. Cu2+-Induced LDL oxidation is inhibited by oleuropein and hydroxytyrosol in the initiation phase of the reaction at concentrations of phenols higher than that of Cu2+ ions. Interestingly, at lower concentration, both phenols anticipated the initiation process of LDL oxidation, thus exerting prooxidant capacities. Although similar effects are already described for flavonoids, such as quercetin, rutin, and apigenin, it is the first time that a prooxidant effect of dietary non-flavonoid phenols, such as oleuropein and hydroxytyrosol, on the LDL oxidation is reported. Our results show that a net effect of oleuropein and hydroxytyrosol on Cu2+-induced LDL peroxidation is determined by a balance of their pro- and antioxidant capacities. It is worth to underline that, during Cu2+-induced LDL oxidation in the presence of bioreactor eluates, we have evidence of a synergistic effect among phenolic compounds that enhance their antioxidant capacities so avoiding the prooxidant effects.

Preparative separation of phenolic compounds from Halimodendron halodendron by high-speed counter-current chromatography.

PubMed

Wang, Jihua; Gao, Haifeng; Zhao, Jianglin; Wang, Qi; Zhou, Ligang; Han, Jianguo; Yu, Zhu; Yang, Fuyu

2010-08-31

Three phenolic compounds, p-hydroxybenzoic acid (1), isorhamnetin-3-O-β-D-rutinoside (2), and 3,3'-di-O-methylquercetin (5), along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC) with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v) as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3) and 3-O-methylquercetin (4). Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC). The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3) and 3-O-methylquercetin (4) (26.43% and 71.89%, respectively) in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5) at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1) at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2) at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

Process for preparing a liquid fuel composition

DOEpatents

Singerman, Gary M.

1982-03-16

A process for preparing a liquid fuel composition which comprises liquefying coal, separating a mixture of phenols from said liquefied coal, converting said phenols to the corresponding mixture of anisoles, subjecting at least a portion of the remainder of said liquefied coal to hydrotreatment, subjecting at least a portion of said hydrotreated liquefied coal to reforming to obtain reformate and then combining at least a portion of said anisoles and at least a portion of said reformate to obtain said liquid fuel composition.

In situ catalytic hydrogenation of model compounds and biomass-derived phenolic compounds for bio-oil upgrading

Treesearch

Junfeng Feng; Zhongzhi Yang; Chung-yun Hse; Qiuli Su; Kui Wang; Jianchun Jiang; Junming Xu

2017-01-01

The renewable phenolic compounds produced by directional liquefaction of biomass are a mixture of complete fragments decomposed from native lignin. These compounds are unstable and difficult to use directly as biofuel. Here, we report an efficient in situ catalytic hydrogenation method that can convert phenolic compounds into saturated cyclohexanes. The process has...

Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor.

PubMed

Almendariz, F J; Meraz, M; Olmos, A D; Monroy, O

2005-01-01

Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SW(CO2)) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L(-1) of phenol, p-cresol and o-cresol, respectively. The mixture was teated anaerobically in an EGSB reactor fed with 1.5 gCOD L(-1) d(-1), without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L(-1) d(-1). The mixture SC/SWco2 added to the phenol load, was step increased from 0.10 to 0.87 gCODL(-1) d(-1) maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.

The effect of different solvents and number of extraction steps on the polyphenol content and antioxidant capacity of basil leaves (Ocimum basilicum L.) extracts.

PubMed

Złotek, Urszula; Mikulska, Sylwia; Nagajek, Małgorzata; Świeca, Michał

2016-09-01

The objectives of this study were to determine best conditions for the extraction of phenolic compounds from fresh, frozen and lyophilized basil leaves. The acetone mixtures with the highest addition of acetic acid extracted most of the phenolic compounds when fresh and freeze-dried material have been used. The three times procedure was more effective than once shaking procedure in most of the extracts obtained from fresh basil leaves - unlike the extracts derived from frozen material. Surprisingly, there were not any significant differences in the content of phenolics between the two used procedures in the case of lyophilized basil leaves used for extraction. Additionally, the positive correlation between the phenolic compounds content and antioxidant activity of the studied extracts has been noted. It is concluded that the acetone mixtures were more effective than the methanol ones for polyphenol extraction. The number of extraction steps in most of the cases was also a statistically significant factor affecting the yield of phenolic extraction as well as antioxidant potential of basil leaf extracts.

Polysaccharide-derived mesoporous materials (Starbon®) for sustainable separation of complex mixtures.

PubMed

Zuin, Vânia G; Budarin, Vitaliy L; De Bruyn, Mario; Shuttleworth, Peter S; Hunt, Andrew J; Pluciennik, Camille; Borisova, Aleksandra; Dodson, Jennifer; Parker, Helen L; Clark, James H

2017-09-21

The recovery and separation of high value and low volume extractives are a considerable challenge for the commercial realisation of zero-waste biorefineries. Using solid-phase extractions (SPE) based on sustainable sorbents is a promising method to enable efficient, green and selective separation of these complex extractive mixtures. Mesoporous carbonaceous solids derived from renewable polysaccharides are ideal stationary phases due to their tuneable functionality and surface structure. In this study, the structure-separation relationships of thirteen polysaccharide-derived mesoporous materials and two modified types as sorbents for ten naturally-occurring bioactive phenolic compounds were investigated. For the first time, a comprehensive statistical analysis of the key molecular and surface properties influencing the recovery of these species was carried out. The obtained results show the possibility of developing tailored materials for purification, separation or extraction, depending on the molecular composition of the analyte. The wide versatility and application span of these polysaccharide-derived mesoporous materials offer new sustainable and inexpensive alternatives to traditional silica-based stationary phases.

Toward the understanding of the molecular basis for the inhibition of COX-1 and COX-2 by phenolic compounds present in Uruguayan propolis and grape pomace.

PubMed

Paulino, Margot; Alvareda, Elena; Iribarne, Federico; Miranda, Pablo; Espinosa, Victoria; Aguilera, Sara; Pardo, Helena

2016-12-01

Propolis and grape pomace have significant amounts of phenols which can take part in anti-inflammatory mechanisms. As the cyclooxygenases 1 and 2 (COX-1 and COX-2) are involved in said mechanisms, the possibility for a selective inhibition of COX-2 was analyzed in vitro and in silico. Propolis and grape pomace from Uruguayan species were collected, extracted in hydroalcoholic mixture and analyzed. Based on phenols previously identified, and taking as reference the crystallographic structures of COX-1 and COX-2 in complex with the commercial drug Celecoxib, a molecular docking procedure was devised to adjust 123 phenolic molecular models at the enzyme-binding sites. The most important results of this work are that the extracts have an overall inhibition activity very similar in COX-1 and COX-2, i.e. they do not possess selective inhibition activity for COX-2. Nevertheless, 10 compounds of the phenolic database turned out to be more selective and 94 phenols resulted with similar selectivity than Celecoxib, an outcome that accounts for the overall experimental inhibition measures. Binding site environment observations showed increased polarity in COX-2 as compared with COX-1, suggesting that polarity is the key for selectivity. Accordingly, the screening of molecular contacts pointed to the residues: Arg106, Gln178, Leu338, Ser339, Tyr341, Tyr371, Arg499, Ala502, Val509, and Ser516, which would explain, at the atomic level, the anti-inflammatory effect of the phenolic compounds. Among them, Gln178 and Arg499 appear to be essential for the selective inhibition of COX-2.

Isolation and identification of phenolic compounds from rum aged in oak barrels by high-speed countercurrent chromatography/high-performance liquid chromatography-diode array detection-electrospray ionization mass spectrometry and screening for antioxidant activity.

PubMed

Regalado, Erik L; Tolle, Sebastian; Pino, Jorge A; Winterhalter, Peter; Menendez, Roberto; Morales, Ana R; Rodríguez, José L

2011-10-14

Beverages, especially wines are well-known to contain a variety of health-beneficial bioactive substances, mainly of phenolic nature which frequently exhibit antioxidant activity. Significant information is available about the separation and identification of polyphenols from some beverages by chromatographic and spectroscopic techniques, but considerably poor is chemical data related to the polyphenolic content in rums. In this paper, a method involving the all-liquid chromatographic technique of high-speed countercurrent chromatography (HSCCC) combined with high-performance liquid chromatography coupled with diode-array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS(n)) has been successfully applied for separation and identification of phenolic compounds in an aged rum. Besides, the phenolic fraction (PF) was assayed for its antioxidant effects using three different free radical in vitro assays (DPPH·, RO(2)· and spontaneous lipid peroxidation (LPO) on brain homogenates) and on ferric reducing antioxidant power (FRAP). Results showed that PF potently scavenged DPPH and strongly scavenged peroxyl radicals compared to ascorbic acid and butylated hydroxytoluene (BHT); and almost equally inhibited LPO on brain homogenates subjected to spontaneous LPO when compared to quercetin. Moreover, PF also exhibited strong reducing power. This chemical analysis illustrates the rich array of phenols in the aged rum and represents a rapid and suitable method for the isolation and identification of phenolic compounds from mixtures of considerable complexity, achieving high purity and reproducibility with the use of two separation steps. Copyright © 2011 Elsevier B.V. All rights reserved.

Inhibition of Helicobacter pylori and Associated Urease by Oregano and Cranberry Phytochemical Synergies

PubMed Central

Lin, Y. T.; Kwon, Y. I.; Labbe, R. G.; Shetty, K.

2005-01-01

Ulcer-associated dyspepsia is caused by infection with Helicobacter pylori. H. pylori is linked to a majority of peptic ulcers. Antibiotic treatment does not always inhibit or kill H. pylori with potential for antibiotic resistance. The objective of this study was to determine the potential for using phenolic phytochemical extracts to inhibit H. pylori in a laboratory medium. Our approach involved the development of a specific phenolic profile with optimization of different ratios of extract mixtures from oregano and cranberry. Subsequently, antimicrobial activity and antimicrobial-linked urease inhibition ability were evaluated. The results indicated that the antimicrobial activity was greater in extract mixtures than in individual extracts of each species. The results also indicate that the synergistic contribution of oregano and cranberry phenolics may be more important for inhibition than any species-specific phenolic concentration. Further, based on plate assay, the likely mode of action may be through urease inhibition and disruption of energy production by inhibition of proline dehydrogenase at the plasma membrane. PMID:16332847

Interaction between Wine Phenolic Acids and Salivary Proteins by Saturation-Transfer Difference Nuclear Magnetic Resonance Spectroscopy (STD-NMR) and Molecular Dynamics Simulations.

PubMed

Ferrer-Gallego, Raúl; Hernández-Hierro, José Miguel; Brás, Natércia F; Vale, Nuno; Gomes, Paula; Mateus, Nuno; de Freitas, Victor; Heredia, Francisco J; Escribano-Bailón, María Teresa

2017-08-09

The interaction between phenolic compounds and salivary proteins is highly related to the astringency perception. Recently, it has been proven the existence of synergisms on the perceived astringency when phenolic acids were tested as mixtures in comparison to individual compounds, maintaining constant the total amount of the stimulus. The interactions between wine phenolic acids and the peptide fragment IB7 12 have been studied by saturation-transfer difference (STD) NMR spectroscopy. This technique provided the dissociation constants and the percentage of interaction between both individual and mixtures of hydroxybenzoic and hydroxycinnamic acids and the model peptide. It is noteworthy that hydroxybenzoic acids showed higher affinity for the peptide than hydroxycinnamic acids. To obtain further insights into the mechanisms of interaction, molecular dynamics simulations have been performed. Results obtained not only showed the ability of these compounds to interact with salivary proteins but also may justify the synergistic effect observed in previous sensory studies.

Process for producing phenolic compounds from lignins

DOEpatents

Agblevor, Foster A.

1998-01-01

A process for the production of low molecular weight phenolic compounds from lignins through the pyrolysis of the lignins in the presence of a strong base. In a preferred embodiment, potassium hydroxide is present in an amount of from about 0.1% to about 5% by weight, the pyrolysis temperature is from about 400.degree. C. to about 600.degree. C. at atmospheric pressure, and the time period for substantial completion of the reaction is from about 1-3 minutes. Examples of low molecular weight phenolic compounds produced include methoxyphenols, non-methoxylated phenols, and mixtures thereof.

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues.

PubMed

Santos Felix, Antonio C; Novaes, Cleber G; Pires Rocha, Maísla; Barreto, George E; do Nascimento, Baraquizio B; Giraldez Alvarez, Lisandro D

2017-01-01

In this study, we have determined, using RSM (mixture design and Doehlert matrix), the optimum values of the independent variables to achieve the maximum response for the extraction of total phenolic compounds from Spondias mombin L bagasse agroindustrial residues in order to preserve their antioxidant activity. The extraction of phenolic compounds, as well as their antioxidant capacity and the capacity to scavenge ABTS, was determined by the modified DPPH method at different periods of time, temperature, velocity of rotation and solvents concentration. We observed that the optimum condition for the highest antioxidant yield was obtained using water (60.84%), acetone (30.31%), and ethanol (8.85%) at 30°C during 20 min at 50 rpm. We have also found that the maximum yield of total phenolics was 355.63 ± 9.77 (mg GAE/100 g), showing an EC 50 of 3,962.24 ± 41.20 (g fruit/g of DPPH) and 8.36 ± 0.30 (μM trolox/g fruit), which were measured using DPPH and ABTS assays. These results suggest that RSM was successfully applied for optimizing the extraction of phenolics compounds thus preserving their antioxidant activity.

Effects of copper on the antioxidant activity of olive polyphenols in bulk oil and oil-in-water emulsions.

PubMed

Paiva-Martins, Fátima; Santos, Vera; Mangericão, Hugo; Gordon, Michael H

2006-05-17

The antioxidant activity and interactions with copper of four olive oil phenolic compounds, namely oleuropein, hydroxytyrosol, 3,4-dihydroxyphenylethanol-elenolic acid (1), and 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde (2), in olive oil and oil-in-water emulsions stored at 60 degrees C were studied. All four phenolic compounds significantly extended the induction time of lipid oxidation in olive oil with the order of activity being hydroxytyrosol > compound 1 > compound 2 > oleuropein > alpha-tocopherol; but in the presence of Cu(ll), the stability of oil samples containing phenolic compounds decreased by at least 90%, and the antioxidant activity of hydroxytyrosol and compounds 1 and 2 became similar. In oil-in-water emulsions prepared from olive oil stripped of tocopherols, hydroxytyrosol enhanced the prooxidant effect of copper at pH 5.5 but not at pH 7.4. The stability of samples containing copper at pH 5.5 was not significantly different if oleuropein was present from that of the control. Oleuropein at pH 7.4, and compounds 1 and 2 at both pH values tested, reduced the prooxidant effect of copper. The lower stability and the higher reducing capacity of all compounds at pH 7.4 could not explain the higher stability of emulsions containing phenolic compounds at this pH value. However, mixtures containing hydroxytyrosol or oleuropein with copper showed higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity at pH 7.4 than at pH 5.5. Moreover, the compound 2-copper complex showed higher radical scavenging activity then the uncomplexed compound at pH 5.5. It can be concluded that the formation of a copper complex with radical scavenging activity is a key step in the antioxidant action of the olive oil phenolic compounds in an emulsion containing copper ions.

Inhibitory Effect of Furanic and Phenolic Compounds on Exoelectrogenesis in a Microbial Electrolysis Cell Bioanode

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2016-09-09

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Dietary induced serum phenolic acids promote bone growth via p38 MAPK / Beta-Catenin Canonical Wnt signaling

USDA-ARS?s Scientific Manuscript database

Diet and nutritional status are critical factors that influences bone development. In this report, we demonstrate that a mixture of phenolic acids found in the serum of young rats fed blueberries (BB), significantly stimulated osteoblast differentiation, resulting in significantly increased bone mas...

FT-IR quantification of the carbonyl functional group in aqueous-phase secondary organic aerosol from phenols

NASA Astrophysics Data System (ADS)

George, Kathryn M.; Ruthenburg, Travis C.; Smith, Jeremy; Yu, Lu; Zhang, Qi; Anastasio, Cort; Dillner, Ann M.

2015-01-01

Recent findings suggest that secondary organic aerosols (SOA) formed from aqueous-phase reactions of some organic species, including phenols, contribute significantly to particulate mass in the atmosphere. In this study, we employ a Fourier transform infrared (FT-IR) spectroscopic technique to identify and quantify the functional group makeup of phenolic SOA. Solutions containing an oxidant (hydroxyl radical or 3,4-dimethoxybenzaldehyde) and either one phenol (phenol, guaiacol, or syringol) or a mixture of phenols mimicking softwood or hardwood emissions were illuminated to make SOA, atomized, and collected on a filter. We produced laboratory standards of relevant organic compounds in order to develop calibrations for four functional groups: carbonyls (Cdbnd O), saturated C-H, unsaturated C-H and O-H. We analyzed the SOA samples with transmission FT-IR to identify and determine the amounts of the four functional groups. The carbonyl functional group accounts for 3-12% of the SOA sample mass in single phenolic SOA samples and 9-14% of the SOA sample mass in mixture samples. No carbonyl functional groups are present in the initial reactants. Varying amounts of each of the other functional groups are observed. Comparing carbonyls measured by FT-IR (which could include aldehydes, ketones, esters, and carboxylic acids) with eight small carboxylic acids measured by ion chromatography indicates that the acids only account for an average of 20% of the total carbonyl reported by FT-IR.

Process for producing phenolic compounds from lignins

DOEpatents

Agblevor, F.A.

1998-09-15

A process is described for the production of low molecular weight phenolic compounds from lignins through the pyrolysis of the lignins in the presence of a strong base. In a preferred embodiment, potassium hydroxide is present in an amount of from about 0.1% to about 5% by weight, the pyrolysis temperature is from about 400 C to about 600 C at atmospheric pressure, and the time period for substantial completion of the reaction is from about 1--3 minutes. Examples of low molecular weight phenolic compounds produced include methoxyphenols, non-methoxylated phenols, and mixtures thereof. 16 figs.

Formation of hydrogen peroxide from illuminated polar snows and frozen solutions of model compounds

NASA Astrophysics Data System (ADS)

Hullar, Ted; Patten, Kelley; Anastasio, Cort

2012-08-01

Hydrogen peroxide (HOOH) is an important trace constituent in snow and ice, including in Arctic and Antarctic ice cores. To better understand the budget of snowpack HOOH, here we examine its production in illuminated snow and ice. To evaluate what types of compounds might be important photochemical sources of HOOH, we first illuminated laboratory ice samples containing 10 different model organic compounds: guaiacol, phenol, syringol, benzoate, formate, octanal, octanoic acid, octanedioic acid, phenylalanine, and mixtures of oxalate with iron (III). Half of these compounds produced little or no HOOH during illumination, but two classes of compounds were very reactive: phenolic compounds (with rates of HOOH of 6-62 nM-HOOH h-1 μM-1-phenolic) and mixtures of Fe(III) with a stoichiometric excess of oxalate (with rates of HOOH production as high as 2,000,000 nM h-1 per μM iron). To quantify rates of HOOH production in the environment we also illuminated snow samples collected from the Arctic and Antarctic. The average (±1σ) HOOH production rate in these samples was low, 5.3 ± 5.0 nM h-1 and replicate measurements showed high variability. In some natural samples there was an initial burst of HOOH production (with a rate approximately 10 times higher than the average production rate), followed by reduced rates at subsequent time points. Although our laboratory ice samples reveal that illuminated organics and metal-organic complexes can form HOOH, the low rates of HOOH formation in the Arctic and Antarctic snow samples suggest this process has only a modest impact on the HOOH budget in the snowpack.

Determination of 4-nonylphenol in water samples using 4-(2,6-dimethylhept-3-yl)phenol as new internal standard.

PubMed

Fischer, Axel R; Lan, Nham Thi Phuong; Wiedemann, Cornelia; Heide, Petra; Werner, Peter; Schmidt, Arndt W; Theumer, Gabriele; Knölker, Hans-Joachim

2010-04-23

A new method for determining the endocrine disrupting substance 4-nonylphenol (technical grade=mixture of isomers, 4-NP) from water samples has been developed by using 4-(2,6-dimethylhept-3-yl)phenol (4-sec-NP) as model compound. This branched monoalkylphenol is shown to serve as internal standard (IS) for the determination of technical 4-nonylphenol. To the best of our knowledge, 4-(2,6-dimethylhept-3-yl)phenol (racemic mixture) is a newly synthesized 4-nonylphenol isomer and has not been described elsewhere. Recoveries have been determined by analyzing spiked water samples from distilled water, river water and wastewater. Following acetylation, the compounds were enriched via solid phase extraction (SPE). Analyses of the compounds were performed by capillary column gas chromatography/mass spectrometry (GC/MS), operating in selected ion-monitoring (SIM) mode. The recovery of technical 4-NP using either the newly prepared 4-sec-NP or 4-n-nonylphenol (4-n-NP) as IS have been compared. 4-sec-NP showed slightly better results. However, in the first series of experiments using wastewater, the yields for the derivatization of the two standard compounds were remarkably different. The yield for derivatization of 4-n-NP was approximately 20%, probably due to the difficult matrix of the wastewater. In contrast, the yield for the derivatization of 4-sec-NP was considerably higher (approximately 63%). This problem can be solved by increasing the concentration of the reagent used for derivatization. For better control of the clean-up process, we recommend application of 4-sec-NP as internal standard, at least in water samples with complex matrices (e.g., high content of hydroxylated compounds). Copyright 2010 Elsevier B.V. All rights reserved.

High-Performance Cellulose Nanofibril Composite Films

Treesearch

Yan Qing; Ronald Sabo; Yiqiang Wu; Zhiyong Cai

2012-01-01

Cellulose nanofibril/phenol formaldehyde (CNF/PF) composite films with high work of fracture were prepared by filtering a mixture of 2,2,6,6tetramethylpiperidine-1-oxyl (TEMPO) oxidized wood nanofibers and water-soluble phenol formaldehyde with resin contents ranging from 5 to 20 wt%, followed by hot pressing. The composites were characterized by tensile testing,...

Phenol-Urea-Formaldehyde (PUF) co-condensed wood adhesives

Treesearch

Bunichiro Tomita; Chung-Yun Hse

1998-01-01

The reaction of urea with methylolphenol under acidic conditions was investigated. The alternating copolymer of urea and phenol could be synthesized by the reaction of urea and 2,4,6-trimethylolphenol. The reactions of urea with polymethylolphenol mixtures also were investigated by changing the reaction conditions, such as the molar ratio and acidity. The co-...

Some phenolic compounds of extracts obtained from Origanum species growing in Turkey.

PubMed

Ozkan, Gülcan; Ozcan, Mehmet Musa

2014-08-01

Caffeic acid, rosmarinic acid, rutin, apigenin 7-O-glucoside, apigenin, and acesetin were the main phenolic compounds of Origanum onites extracts in all applications. While acesetin contents ranged from 133.59 mg/100 g (U1) to 437.25 mg/100 g (S3), rosmarinic acid changed between 215.94 mg/100 g (U4) and 1120.56 mg/100 g (S2) in Origanum vulgare L. subsp. hirtum (Link) Ietsw. Both rosmarinic acid and acesetin were not found in U5 application. Only caffeic acid (19.39 mg/100 g) was found in U5 application. Rosmarinic acid contents of O. onites extract changed between 158.62 mg/100 g (U5) and 799.87 mg/100 g (S2). Generally, dominant phenolic compound of Origanum extracts was rosmarinic acid compared with other extracts. In addition, methanol:water:acetic acid mixture (S2) (95:4.5:0.5) was found as the best application. Phenolic contents of extracts obtained with U series mixtures were found low.

Complex enzyme hydrolysis releases antioxidative phenolics from rice bran.

PubMed

Liu, Lei; Wen, Wei; Zhang, Ruifen; Wei, Zhencheng; Deng, Yuanyuan; Xiao, Juan; Zhang, Mingwei

2017-01-01

In this study, phenolic profiles and antioxidant activity of rice bran were analyzed following successive treatment by gelatinization, liquefaction and complex enzyme hydrolysis. Compared with gelatinization alone, liquefaction slightly increased the total amount of phenolics and antioxidant activity as measured by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Complex enzyme hydrolysis significantly increased the total phenolics, flavonoids, FRAP and ORAC by 46.24%, 79.13%, 159.14% and 41.98%, respectively, compared to gelatinization alone. Furthermore, ten individual phenolics present in free or soluble conjugate forms were also analyzed following enzymatic processing. Ferulic acid experienced the largest release, followed by protocatechuic acid and then quercetin. Interestingly, a major proportion of phenolics existed as soluble conjugates, rather than free form. Overall, complex enzyme hydrolysis releases phenolics, thus increasing the antioxidant activity of rice bran extract. This study provides useful information for processing rice bran into functional beverage rich in phenolics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inhibition on cholinesterase and tyrosinase by alkaloids and phenolics from Aristotelia chilensis leaves.

PubMed

Cespedes, Carlos L; Balbontin, Cristian; Avila, Jose G; Dominguez, Mariana; Alarcon, Julio; Paz, Cristian; Burgos, Viviana; Ortiz, Leandro; Peñaloza-Castro, Ignacio; Seigler, David S; Kubo, Isao

2017-11-01

It is reported in this study the effect of isolates from leaves of Aristotelia chilensis as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes. The aim of the paper was to evaluate the activity of A. chilensis towards different enzymes. In addition to pure compounds, extracts rich in alkaloids and phenolics were tested. The most active F5 inhibited AChE (79.5% and 89.8% at 10.0 and 20.0 μg/mL) and against BChE (89.5% and 97.8% at 10.0 and 20.0 μg/mL), showing a strong mixed-type inhibition against AChE and BChE. F3 (a mixture of flavonoids and phenolics acids), showed IC 50 of 90.7 and 59.6 μg/mL of inhibitory activity against AChE and BChE, inhibiting the acetylcholinesterase competitively. Additionally, F3 showed and high potency as tyrosinase inhibitor with IC 50 at 8.4 μg/mL. Sample F4 (anthocyanidins and phenolic composition) presented a complex, mixed-type inhibition of tyrosinase with a IC 50 of 39.8 μg/mL. The findings in this investigation show that this natural resource has a strong potential for future research in the search of new phytotherapeutic treatments for cholinergic deterioration ailments avoiding the side effects of synthetic drugs. This is the first report as cholinesterases and tyrosinase inhibitors of alkaloids and phenolics from A. chilensis leaves. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of Polyhenolic Content of Rose Hip (Rosa canina L.) Tea Extracts: A Comparative Study

PubMed Central

İlbay, Zeynep; Şahin, Selin; Kırbaşlar, Ş. İsmail

2013-01-01

Three different brands of Rose hip (Rosa canina L.) tea were extracted with water, ethanol (EtOH), methanol (MeOH), and aqueous mixtures (50%, v/v) by ultrasound-assisted extraction (UAE) and Soxhlet methods. Total phenolic content was determined according to the Folin-Ciocalteu method. The results were presented by means of the extract yields and total phenolic contents, expressed in gallic acid equivalent (GAE) per g of dried matter (DM). The greatest amount of extract observed in tea samples was obtained by UAE through water with the value of 619.37 ± 0.58 mg/g DM. Regarding the phenolic content, the best result was achieved by the Soxhlet method through 50% MeOH mixture (59.69 ± 0.89 mg GAE/g DM), followed by the UAE method with water (48.59 ± 0.29 mg GAE/g DM). PMID:28239095

Comparison of the free and bound phenolic profiles and cellular antioxidant activities of litchi pulp extracts from different solvents

PubMed Central

2014-01-01

Background The phenolic contents and antioxidant activities of fruits could be underestimated if the bound phenolic compounds are not considered. In the present study, the extraction efficiencies of various solvents were investigated in terms of the total content of the free and bound phenolic compounds, as well as the phenolic profiles and antioxidant activities of the extracts. Methods Five different solvent mixtures were used to extract the free phenolic compounds from litchi pulp. Alkaline and acidic hydrolysis methods were compared for the hydrolysis of bound phenolic compounds from litchi pulp residue. The phenolic compositions of the free and bound fractions from the litchi pulp were identified using HPLC-DAD. The antioxidant activities of the litchi pulp extracts were determined by oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) assays. Results Of the solvents tested, aqueous acetone extracted the largest amount of total free phenolic compounds (210.7 mg GAE/100 g FW) from litchi pulp, followed sequentially by aqueous mixtures of methanol, ethanol and ethyl acetate, and water itself. The acid hydrolysis method released twice as many bound phenolic compounds as the alkaline hydrolysis method. Nine phenolic compounds were detected in the aqueous acetone extract. In contrast, not all of these compounds were found in the other four extracts. The classification and content of the bound phenolic compounds released by the acid hydrolysis method were higher than those achieved by the alkaline hydrolysis. The aqueous acetone extract showing the highest ORAC value (3406.9 μmol TE/100 g FW) for the free phenolic extracts. For the CAA method, however, the aqueous acetone and methanol extracts (56.7 and 55.1 μmol QE/100 g FW) showed the highest levels of activity of the five extracts tested. The ORAC and CAA values of the bound phenolic compounds obtained by acid hydrolysis were 2.6- and 1.9-fold higher than those obtained using the alkaline hydrolysis method. Conclusions The free and bound phenolic contents and profiles and antioxidant activities of the extracts were found to be dependent on the extraction solvent used. Litchi exhibited good cellular antioxidant activity and could be a potentially useful natural source of antioxidants. PMID:24405977

Mixture design and Doehlert matrix for the optimization of the extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agro-industrial Residues

NASA Astrophysics Data System (ADS)

Santos Felix, Antonio C.; Novaes, Cleber G.; Pires Rocha, Maísla; Barreto, George E.; do Nascimento, Baraquizio B.; Giraldez Alvarez, Lisandro D.

2017-12-01

In this study, we have determined, using RSM (mixture design and Doehlert matrix), the optimum values of the independent variables to achieve the maximum response for the extraction of total phenolic compounds from Spondias mombin L bagasse agroindustrial residues, preserving its antioxidant activity. The assessment with reference to the extraction of phenolic compounds, as well as their capacity to scavenge ABTS and the antioxidant capacity, determined by the modified DPPH method were investigated based on distinct combinations of time, temperature, velocity of rotation and solvents concentration. It was investigated that the optimum condition for the highest antioxidant yield was obtained using water (60.84%), acetone (30.31%) and ethanol (8.85%) at 30 ºC during 20 min at 50 rpm. We have found that the maximum yield of total phenolics was 355.63 ± 9.77 (mg GAE/100 g), showing an EC50 of 3962.24 ± 41.20 (g fruit/g of DPPH) and 8.36 ± 0.30 (µM trolox/g fruit), which were measured using DPPH and ABTS assays. These results suggest that RSM was successfully applied for optimizing the extraction of phenolics compounds preserving its antioxidant activity. This method does not require expensive reagents or high quantities of organic solvents.

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues

PubMed Central

Santos Felix, Antonio C.; Novaes, Cleber G.; Pires Rocha, Maísla; Barreto, George E.; do Nascimento, Baraquizio B.; Giraldez Alvarez, Lisandro D.

2018-01-01

In this study, we have determined, using RSM (mixture design and Doehlert matrix), the optimum values of the independent variables to achieve the maximum response for the extraction of total phenolic compounds from Spondias mombin L bagasse agroindustrial residues in order to preserve their antioxidant activity. The extraction of phenolic compounds, as well as their antioxidant capacity and the capacity to scavenge ABTS, was determined by the modified DPPH method at different periods of time, temperature, velocity of rotation and solvents concentration. We observed that the optimum condition for the highest antioxidant yield was obtained using water (60.84%), acetone (30.31%), and ethanol (8.85%) at 30°C during 20 min at 50 rpm. We have also found that the maximum yield of total phenolics was 355.63 ± 9.77 (mg GAE/100 g), showing an EC50 of 3,962.24 ± 41.20 (g fruit/g of DPPH) and 8.36 ± 0.30 (μM trolox/g fruit), which were measured using DPPH and ABTS assays. These results suggest that RSM was successfully applied for optimizing the extraction of phenolics compounds thus preserving their antioxidant activity. PMID:29354632

Evaluation of solvent effect on the extraction of phenolic compounds and antioxidant capacities from the berries: application of principal component analysis.

PubMed

Boeing, Joana Schuelter; Barizão, Erica Oliveira; E Silva, Beatriz Costa; Montanher, Paula Fernandes; de Cinque Almeida, Vitor; Visentainer, Jesuí Vergilio

2014-01-01

This study evaluated the effect of the solvent on the extraction of antioxidant compounds from black mulberry (Morus nigra), blackberry (Rubus ulmifolius) and strawberry (Fragaria x ananassa). Different extracts of each berry were evaluated from the determination of total phenolic content, anthocyanin content and antioxidant capacity, and data were applied to the principal component analysis (PCA) to gain an overview of the effect of the solvent in extraction method. For all the berries analyzed, acetone/water (70/30, v/v) solvent mixture was more efficient solvent in the extracting of phenolic compounds, and methanol/water/acetic acid (70/29.5/0.5, v/v/v) showed the best values for anthocyanin content. Mixtures of ethanol/water (50/50, v/v), acetone water/acetic acid (70/29.5/0.5, v/v/v) and acetone/water (50/50, v/v) presented the highest antioxidant capacities for black mulberries, blackberries and strawberries, respectively. Antioxidants extractions are extremely affected by the solvent combination used. In addition, the obtained extracts with the organic solvent-water mixtures were distinguished from the extracts obtained with pure organic solvents, through the PCA analysis.

Induction of a viable but not culturable (VBNC) state in some Pseudomonas syringae pathovars upon exposure to oxidation of an apoplastic phenolic, acetosyringone

USDA-ARS?s Scientific Manuscript database

Acetosyringone is a phenolic metabolite often found in plant apoplasts. Its oxidation by hydrogen peroxide and peroxidase results in a prolonged increase in the redox potential of the reaction mixture, similar to redox increases observed in suspension cells upon treatment with incompatible bacteri...

Xylosylation of Phenolic Hydroxyl Groups of the Monomeric Lignin Model Compounds 4-Methylguaiacol and Vanillyl Alcohol by Coriolus versicolor

PubMed Central

Kondo, Ryuichiro; Yamagami, Hikari; Sakai, Kokki

1993-01-01

When 4-methylguaiacol (MeG), a phenolic lignin model compound, was added to a culture that was inoculated with Coriolus versicolor, it was bioconverted into 2-methoxy-4-methylphenyl β-d-xyloside (MeG-Xyl). The phenolic hydroxyl group of vanillyl alcohol was much more extensively xylosylated than the alcoholic hydroxyl group. When a mixture of MeG and commercial UDP-xylose was incubated with cell extracts of mycelia, transformation of UDP-xylose into MeG-Xyl was observed. This result suggested that UDP-xylosyltransferase was involved in the xylosylation of phenolic hydroxyl groups of lignin model compounds. PMID:16348869

Fermentation and complex enzyme hydrolysis enhance total phenolics and antioxidant activity of aqueous solution from rice bran pretreated by steaming with α-amylase.

PubMed

Liu, Lei; Zhang, Ruifen; Deng, Yuanyuan; Zhang, Yan; Xiao, Juan; Huang, Fei; Wen, Wei; Zhang, Mingwei

2017-04-15

In this study, rice bran was successively steamed with α-amylase, fermented with lactic acid bacteria, and hydrolyzed with complex enzymes. The changes in phenolic profiles and antioxidant activities of the corresponding aqueous solutions from three stages were investigated. Compared to the first stage, fermentation and complex enzyme hydrolysis significantly increased the total phenolics, total flavonoids, total FRAP and ORAC values by 59.2%, 56.6%, 73.6% and 45.4%, respectively. Twelve individual phenolics present in free or soluble conjugate forms were also analyzed during the processing. Ferulic acid was released in the highest amount among different phenolics followed by protocatechuic acid. Moreover, a major proportion of phenolics existed as soluble conjugates. The results showed that fermentation and complex enzyme hydrolysis enhanced total phenolics and antioxidant activities of aqueous solution from rice bran pretreated by steaming with α-amylase. This research could provide basis for the processing of rice bran beverage rich in phenolics. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali Sinag; Melike Sungur; Muammer Canel

Copyrolysis of a Turkish lignite with low-density polyethylene (LDPE) is conducted in a tubular reactor. The effect of experimental conditions (temperature of 400-700{sup o}C, catalyst, LDPE contents of the mixture are 33, 50, and 67 wt %) on the formation of tar, gas, and char and their effects on the formation of phenol are investigated. The catalysts used are red mud (which is a waste product of an aluminum factory in Turkey), zeolite (Linde type A (LTA)), and K{sub 2}CO{sub 3}. Tar evolution is determined to be increased significantly by increasing the LDPE content of the coal-LDPE mixture during themore » pyrolysis. The effect of adding LDPE to the coal on the gas generation is not remarkable. An increase in temperature leads to increased gas yields. Phenol and phenol derivatives are the obstacles for the complete conversion of lignite to tar and gas. To investigate this negative effect of phenols on the yields, the phenols found in tar from coal pyrolysis are detected by gas chromatography-mass spectroscopy (GC-MS), and it is observed that phenolic structures detected in the tar obtained by individual pyrolysis of coal are dramatically decreased by adding polymer to the coal. The use of catalysts during the copyrolysis procedure leads to improved gas generation. The possible reasons of these variations are discussed. A remarkable synergetic effect between lignite and LDPE on the tar yields is also observed. 21 refs., 8 figs., 4 tabs.« less

Transport properties associated with carbon-phenolic ablators

NASA Technical Reports Server (NTRS)

Biolsi, L.

1982-01-01

Entry vehicle heat shields designed for entry into the atmosphere of the outer planets are usually made of carbonaceous material such as carbon-phenolic ablator. Ablative injection of this material is an important mechanism for reducing the heat at the surface of the entry vehicle. Conductive transport properties in the shock layer are important for some entry conditions. The kinetic theory of gases has been used to calculate the transport properties for 17 gaseous species obtained from the ablation of carbon-phenolic heat shields. Results are presented for the pure species and for the gas mixture.

Sea buckthorn (Hippophae rhamnoides) proanthocyanidins inhibit in vitro enzymatic hydrolysis of protein.

PubMed

Arimboor, Ranjith; Arumughan, C

2011-08-01

Interactions of phenolics with other food constituents and digestive enzymes are likely to have interference with the digestion and bioavailability of food and phenolics. In this study the effect of sea buckthorn proanthocyanidins on in vitro digestion of protein was evaluated. Optimization of the extraction conditions showed that maximum recovery of sea buckthorn proanthocyanidins was obtained with acidified acetone; water mixture (60% to 70%, v/v). Crude proanthocyanidin extracts thus prepared were purified using sephadex gel column chromatography and their average degree of polymerization and the effects on enzymatic hydrolysis of bovine serum albumin as influenced by their protein precipitation capacities were studied. Average degree of polymerization of proanthocyanidins in berry pulp, kernel, seed coat, and leaves was 7.4, 5.6, 8.2, and 10.6, respectively. The EC50 values for the protein precipitation by the PA of berry pulp, kernel seed coat, and leaves were 44.2, 44.1, 65.8, and 39.8 μg, respectively. Relative enzymatic hydrolysis of the protein-proanthocyanidin complexes was 44.1% to 60.3% for pepsin and 57.5% to 67.7% for trypsin. Interactions of sea buckthorn proanthocyanidins with food proteins and digestive enzymes might alter the protein digestibility and phenolic bioavailabilty. © 2011 Institute of Food Technologists®

Tunable catalytic properties of bi-functional mixed oxides in ethanol conversion to high value compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramasamy, Karthikeyan K.; Gray, Michel J.; Job, Heather M.

2016-04-10

tA highly versatile ethanol conversion process to selectively generate high value compounds is pre-sented here. By changing the reaction temperature, ethanol can be selectively converted to >C2alcohols/oxygenates or phenolic compounds over hydrotalcite derived bi-functional MgO–Al2O3cata-lyst via complex cascade mechanism. Reaction temperature plays a role in whether aldol condensationor the acetone formation is the path taken in changing the product composition. This article containsthe catalytic activity comparison between the mono-functional and physical mixture counterpart to thehydrotalcite derived mixed oxides and the detailed discussion on the reaction mechanisms.

Tunable catalytic properties of bi-functional mixed oxides in ethanol conversion to high value compounds

DOE PAGES

Ramasamy, Karthikeyan K.; Gray, Michel; Job, Heather; ...

2016-02-03

Here, a highly versatile ethanol conversion process to selectively generate high value compounds is presented here. By changing the reaction temperature, ethanol can be selectively converted to >C 2 alcohols/oxygenates or phenolic compounds over hydrotalcite derived bi-functional MgO–Al 2O 3 catalyst via complex cascade mechanism. Reaction temperature plays a role in whether aldol condensation or the acetone formation is the path taken in changing the product composition. This article contains the catalytic activity comparison between the mono-functional and physical mixture counterpart to the hydrotalcite derived mixed oxides and the detailed discussion on the reaction mechanisms.

Temperature dependence of the vapour tension of methyl-substituted phenol derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.G. Gagarin

2007-05-15

Notable among the coking products of coal are phenol and its derivatives, derived for the coal tar and water layer above ht tar. Given that phenol an its derivatives are mainly extracted from coal tar fractions by rectification, information on how the vapor tension of the individual components depends on the temperature is of great importance. For phenol and various substituted alkylphenols there are tabular data. In the pre-computer era these data were sufficient for the separation of phenol mixtures. However, the development and introduction of information technology in the coal industry and in the design process demands the mathematicalmore » description of the physicochemical processes of coking products. The temperature dependence of the saturated vapor pressure for organic compounds is commonly described by the Antoine equation.« less

Evolution of mixed surfactant aggregates in solutions and at solid/solution interfaces

NASA Astrophysics Data System (ADS)

Zhang, Rui

Surfactant systems have been widely used in such as enhanced oil recovery, waste treatment and metallurgy, etc., in order to solve the problem of global energy crisis, to remove the pollutants and to generate novel energy resources. Almost all surfactant systems are invariably mixtures due to beneficial and economic considerations. The sizes and shapes of aggregates in solutions and at solid/solution interfaces become important, since the nanostructures of mixed aggregates determine solution and adsorption properties. A major hurdle in science is the lack of information on the type of complexes and aggregates formed by mixtures and the lack of techniques for deriving such information. Using techniques such as analytical ultracentrifuge, small angle neutron scattering, surface tension, fluorescence, cryo-TEM, light scattering and ultrafiltration, the nanostructures of aggregates of sugar based n-dodecyl-beta-D-maltoside (DM) and nonionic pentaethyleneglycol monododecyl ether or nonyl phenol ethoxylated decyl ether (NP-10) and their mixtures have been investigated to prove the hypothesis that the aggregation behavior is linked to packing of the surfactant governed by the molecular interactions as well as the molecular structures. The results from both sedimentation velocity and sedimentation equilibrium experiments suggest coexistence of two types of micelles in nonyl phenol ethoxylated decyl ether solutions and its mixtures with n-dodecyl-beta-D-maltoside while only one micellar species is present in n-dodecyl-beta-D-maltoside solutions, in good agreement with those from small angle neutron scattering, cryo-TEM, light scattering and ultrafiltration. Type I micelles were primary micelles at cmc while type II micelles were elongated micelles. On the other hand, the nanostructures of mixed surface aggregates have been quantitatively predicted for the first time using a modified packing index. As a continuation of the Somasundaran-Fuersteneau adsorption model, a modified one-step model has been developed to fully understand the adsorption behavior of surfactant mixtures and obtained thermodynamic information on aggregation number and standard free energy for surface aggregation. The findings are expected to provide fundamental basis for the design optimal surfactant schemes for desired purposes.

The oxidation of phenol by ferrate(VI) and ferrate(V). A pulse radiolysis and stopped-flow study.

PubMed

Rush, J D; Cyr, J E; Zhao, Z; Bielski, B H

1995-04-01

Potassium ferrate, K2FeO4, is found to oxidize phenol in aqueous solution (5.5 < or = pH < or = 10) by a process which is second order in both reactants; -d[FeVI]/dt=k1[FeVI][phenol], k1 = 10(7)M-1s-1. Product analysis by HPLC showed a mixture of hydroxylated products, principally paraquinone, and biphenols that indicate that oxidation of phenol occurs by both one-electron and two-electron pathways. The two-electron oxidant, producing both para- and ortho-hydroxylated phenols is considered to be ferrate(V) which is itself produced by the initial one-electron reduction of ferrate(VI). The rate of ferrate(V) reaction with phenol was determined by pre-mix stopped flow pulse-radiolysis and found to be k7 = (3.8 +/- 0.4) x 10(5)M-1s-1.

Changes of turbidity during the phenol oxidation by photo-Fenton treatment.

PubMed

Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez, Jonatan

2014-11-01

Turbidity presented by phenol solutions oxidized with Fenton reagent shows the tendency of a first order intermediate kinetics. Thus, turbidity can be considered a representative parameter of the presence of intermediate oxidation species, which are generated along the decomposition of toxic and reluctant contaminants, such as phenol. Moreover, that parameter presents a linear dependence with the catalyst dosage, but is also determined by the initial contaminant load. When analyzing the oxidation mechanism of phenol, it is found that the maximum turbidity occurs when the treatment is carried out at oxidant to phenol molar ratios R = 4.0. These oxidation conditions correspond to the presence of a reaction mixture mainly composed of dihydroxylated rings, precursors of the muconic acid formation. The oxidation via "para" comprises the formation reactions of charge transfer complexes (quinhydrone), between the para-dihydroxylated intermediates (hydroquinone) and the para-substituted quinones (p-benzoquinone), which are quite unstable and reactive species, quickly decomposed into hydroxyhydroquinones. Working with oxidant ratios up to R = 6.0, the maximum observed value of turbidity in the oxidized solutions is kept almost constant. It is found that, in these conditions, the pyrogallol formation is maximal, what is generated through the degradation of ortho-species (catechol and ortho-benzoquinone) and meta-substituted (resorcinol). Operating with ratios over R = 6.0, these intermediates are decomposed into biodegradable acids, generating lower turbidity in the solution. Then, the residual turbidity is a function of the molar ratio of the ferrous ions vs. moles of oxidant utilized in the essays, that lets to estimate the stoichiometric dosage of catalyst as 20 mg/L at pH = 3.0, whereas operating in stoichiometric conditions, R = 14.0, the residual turbidity of water results almost null.

Fermentation and complex enzyme hydrolysis for improving the total soluble phenolic contents, flavonoid aglycones contents and bio-activities of guava leaves tea.

PubMed

Wang, Lu; Luo, You; Wu, Yanan; Liu, Yan; Wu, Zhenqiang

2018-10-30

There are both soluble and insoluble-bound forms of phenolics in tea-leaf products. In order to increase total soluble phenolics contents, guava leaves tea (GLT) was first fermented with Monascus anka and Saccharomyces cerevisiae, and then hydrolyzed with complex enzymes. The changes in phenolics profiles, antioxidant activities and inhibitory effect on α-glucosidase in processed GLT were investigated. Compared with the un-fermented GLT, fermentation and complex enzymatic processing (FE) significantly increased the total phenolics, total flavonoids, quercetin and kaempferol contents by 2.1, 2.0, 13.0 and 6.8 times, respectively. After the FE, a major proportion of phenolics existed in the soluble form. Quercetin was released in the highest amount among different phenolics. In addition, soluble phenolic extracts from GLT following FE exhibited a highest antioxidant activity and inhibitory effect on α-glucosidase. The paper suggested an improved method for processing GLT into high-value products rich in phenolics and flavonoids aglycones with enhanced health benefits. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation and Mineralization of Phenol Compounds with Goethite Catalyst and Mineralization Prediction Using Artificial Intelligence

PubMed Central

Tisa, Farhana; Davoody, Meysam; Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

2015-01-01

The efficiency of phenol degradation via Fenton reaction using mixture of heterogeneous goethite catalyst with homogeneous ferrous ion was analyzed as a function of three independent variables, initial concentration of phenol (60 to 100 mg /L), weight ratio of initial concentration of phenol to that of H2O2 (1: 6 to 1: 14) and, weight ratio of initial concentration of goethite catalyst to that of H2O2 (1: 0.3 to 1: 0.7). More than 90 % of phenol removal and more than 40% of TOC removal were achieved within 60 minutes of reaction. Two separate models were developed using artificial neural networks to predict degradation percentage by a combination of Fe3+ and Fe2+ catalyst. Five operational parameters were employed as inputs while phenol degradation and TOC removal were considered as outputs of the developed models. Satisfactory agreement was observed between testing data and the predicted values (R2 Phenol = 0.9214 and R2TOC= 0.9082). PMID:25849556

Changes in the contents and profiles of selected phenolics, soyasapogenols, tocopherols, and amino acids during soybean-rice mixture cooking: Electric rice cooker vs electric pressure rice cooker.

PubMed

Kim, Seung-Hyun; Yu, Bo-Ra; Chung, Ill-Min

2015-06-01

This study investigated the changes in the contents and profiles of 35 phenolics (including 12 isoflavones), four tocopherols, two soyasapogenols and 20 amino acids when soybean and rice were cooked together (soybean-rice mixture) using either an electric rice cooker (ERC) or an electric pressure rice cooker (EPRC). The contents of the 35 selected phenolics in soybean decreased by 12% and 8% upon cooking by ERC and EPRC, respectively, and their profiles were different from that prior to cooking (P<0.05). Total tocopherol content of soybeans decreased by 7% after cooking in an ERC, but increased by 3% in soybeans cooked by EPRC. Total soyasapogenol content in soybeans cooked by ERC and EPRC decreased by 15% and 6%, respectively. Lastly, the total amino acid content of soybeans increased by 41% and 10% after cooking by ERC and EPRC, respectively. This study extends our knowledge about the effects of heat and pressure on the contents and profiles of bioactive compounds during soybean-rice mixture cooking. These results may be useful for improving the quality of bioactive compounds in soybean and rice depending on cooking conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Catalytic molecularly imprinted polymer membranes: development of the biomimetic sensor for phenols detection.

PubMed

Sergeyeva, T A; Slinchenko, O A; Gorbach, L A; Matyushov, V F; Brovko, O O; Piletsky, S A; Sergeeva, L M; Elska, G V

2010-02-05

Portable biomimetic sensor devices for the express control of phenols content in water were developed. The synthetic binding sites mimicking active site of the enzyme tyrosinase were formed in the structure of free-standing molecularly imprinted polymer membranes. Molecularly imprinted polymer membranes with the catalytic activity were obtained by co-polymerization of the complex Cu(II)-catechol-urocanic acid ethyl ester with (tri)ethyleneglycoldimethacrylate, and oligourethaneacrylate. Addition of the elastic component oligourethaneacrylate provided formation of the highly cross-linked polymer with the catalytic activity in a form of thin, flexible, and mechanically stable membrane. High accessibility of the artificial catalytic sites for the interaction with the analyzed phenol molecules was achieved due to addition of linear polymer (polyethyleneglycol Mw 20,000) to the initial monomer mixture before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) were formed. The cross-linked component of the semi-IPN was represented by the highly cross-linked catalytic molecularly imprinted polymer, while the linear one was represented by polyethyleneglycol Mw 20,000. Extraction of the linear polymer from the fully formed semi-IPN resulted in formation of large pores in the membranes' structure. Concentration of phenols in the analyzed samples was detected using universal portable device oxymeter with the oxygen electrode in a close contact with the catalytic molecularly imprinted polymer membrane as a transducer. The detection limit of phenols detection using the developed sensor system based on polymers-biomimics with the optimized composition comprised 0.063 mM, while the linear range of the sensor comprised 0.063-1 mM. The working characteristics of the portable sensor devices were investigated. Storage stability of sensor systems at room temperature comprised 12 months (87%). As compared to traditional methods of phenols detection the developed sensor system is characterized by simplicity of operation, compactness, and low cost. Copyright 2009 Elsevier B.V. All rights reserved.

Reducing the allergenic capacity of peanut extracts and liquid peanut butter by phenolic compounds.

USDA-ARS?s Scientific Manuscript database

Phenolic compounds are known to form soluble and insoluble complexes with proteins. The objective of this study was to determine if phenolics, such as, caffeic, chlorogenic, and ferulic acids form insoluble and irreversible complexes with major peanut allergens. We also tested whether such complexat...

Influence of Protein-Phenolic Complex on the Antioxidant Capacity of Flaxseed (Linum usitatissimum L.) Products.

PubMed

Guimarães Drummond E Silva, Fernanda; Miralles, Beatriz; Hernández-Ledesma, Blanca; Amigo, Lourdes; Iglesias, Amadeu Hoshi; Reyes Reyes, Felix Guillermo; Netto, Flavia Maria

2017-02-01

The impact of the naturally present phenolic compounds and/or proteins on the antioxidant capacity of flaxseed products (phenolic fraction, protein concentrates, and hydrolysates) before and after simulated gastrointestinal digestion was studied. For that, whole and phenolic reduced products were assessed. Four glycosylated phenolic compounds (secoisolariciresinol and ferulic, p-coumaric, and caffeic acids) were identified in flaxseed products. Phenolic fraction exerts the highest antioxidant capacity that increased by alkaline hydrolysis and by simulated gastrointestinal digestion. The action of Alcalase and digestive enzymes resulted in an increase of the antioxidant capacity of whole and phenolic reduced products. Principal component analysis showed that proteinaceous samples act as antioxidant is by H + transfer, while those samples containing phenolic compounds exert their effects by both electron donation and H + transfer mechanisms. Protein/peptide-phenolic complexation, confirmed by fluorescence spectra, exerted a positive effect on the antioxidant capacity, mainly in protein concentrates.

Absorption spectrometric and thermodynamic study of charge transfer complexes of menadione (Vitamin K 3) with a series of phenols

NASA Astrophysics Data System (ADS)

Pal, Purnendu; Bhattacharya, Sumanta; Mukherjee, Asok K.; Mukherjee, Dulal C.

2005-03-01

The electron donor-acceptor (EDA) interactions between menadione (i.e., 2-methyl-1,4-naphthoquinone, which is also called 'Vitamin K 3') and a series of phenols (viz., phenol, resorcinol and p-quinol) have been studied in CCl 4 medium. In all the cases, charge transfer (CT) bands have been located. The CT transition energies ( hνCT) of the complexes are found to change systematically with change in the number and position of the -OH groups in the aromatic ring of the phenol moiety. From the trends in the hνCT values, the Hückel parameters ( hÖ and kC-Ö) for the -OH group have been obtained. The CT transition energies are well correlated with the ionisation potentials of the phenols. From an analysis of this variation the electron affinity of Vitamin K 3 has been found to be 2.28 eV. The stoichiometry of the complexes in each case has been found to be 1(menadione):2 (phenol). Formation constants of the complexes have been determined at four different temperatures from which the enthalpies and entropies of formation of the complexes have been estimated.

Absorption spectrometric and thermodynamic study of charge transfer complexes of menadione (Vitamin K3) with a series of phenols.

PubMed

Pal, Purnendu; Bhattacharya, Sumanta; Mukherjee, Asok K; Mukherjee, Dulal C

2005-03-01

The electron donor-acceptor (EDA) interactions between menadione (i.e., 2-methyl-1,4-naphthoquinone, which is also called 'Vitamin K3') and a series of phenols (viz., phenol, resorcinol and p-quinol) have been studied in CCl4 medium. In all the cases, charge transfer (CT) bands have been located. The CT transition energies (h nu(CT)) of the complexes are found to change systematically with change in the number and position of the -OH groups in the aromatic ring of the phenol moiety. From the trends in the h nu(CT) values, the Hückel parameters (h(O) and k(C-O)) for the -OH group have been obtained. The CT transition energies are well correlated with the ionisation potentials of the phenols. From an analysis of this variation the electron affinity of Vitamin K3 has been found to be 2.28 eV. The stoichiometry of the complexes in each case has been found to be 1(menadione):2 (phenol). Formation constants of the complexes have been determined at four different temperatures from which the enthalpies and entropies of formation of the complexes have been estimated.

Inhibitory effect of betel quid on the volatility of methyl mercaptan.

PubMed

Wang, C K; Chen, S L; Wu, M G

2001-04-01

Betel quid, a popular natural masticatory in Taiwan, is mainly composed of fresh areca fruit, Piper betle (leaf or inflorescence), and slaked lime paste. People say that halitosis disappears during betel quid chewing. In this study, the removal of mouth odor during betel quid chewing was discussed by using a model system which measured its inhibition on the volatility of methyl mercaptan. Results showed that crude extracts of betel quid (the mixture of areca fruit, Piper betle, and slaked lime paste) and extracts of the mixture of areca fruit and slaked lime paste exhibited marked effects on the volatility of methyl mercaptan, and the inhibition function increased when increasing amounts of slaked lime paste were added. The same condition (increased inhibition) was also found by replacing the slaked lime paste with alkaline salts (calcium hydroxide, potassium hydroxide, or sodium hydroxide). Areca fruit, the major ingredient of betel quid, contained abundant phenolics. However, the crude phenolic extract of areca fruit did not show any inhibitory activity on the volatility of methyl mercaptan. Great inhibitory activity occurred only when the crude phenolic extract of areca fruit was treated with alkali. Further studies by using gel filtration determined that the effect probably came from the oxidative polymerization of phenolics of areca fruit after alkaline treatment.

Polyphenolic composition and antioxidant capacity of legume based swards are affected by light intensity in a Mediterranean agroforestry system.

PubMed

Re, Giovanni Antonio; Piluzza, Giovanna; Sanna, Federico; Molinu, Maria Giovanna; Sulas, Leonardo

2018-06-01

In Mediterranean grazed woodlands, microclimate changes induced by trees influence the growth and development of the understory, but very little is known about its polyphenolic composition in relation to light intensity. We investigated the bioactive compounds and antioxidant capacity of different legume-based swards and variations due to full sunlight and partial shade. The research was carried out in a cork oak agrosilvopastoral system in Sardinia. The highest values of DPPH reached 7 mmol TEAC 100 g -1 DW, total phenolics 67.1 g GAE kg -1 DW and total flavonoids 7.5 g CE kg -1 DW. Compared to full sunlight, partial shade reduced DPPH values by 29 and 42%, and the total phenolic content by 23 and 53% in 100% legume mixture and semi natural pasture. Twelve phenolic compounds were detected: chlorogenic acid in 80% legume mixture (partial shade) and verbascoside in pure sward of bladder clover (full sunlight) were the most abundant. Light intensity significantly affected antioxidant capacity, composition and levels of phenolic compounds. Our results provide new insights into the effects of light intensity on plant secondary metabolites from legume based swards, underlining the important functions provided by agroforestry systems. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Photo-Fenton degradation of phenol, 2,4-dichlorophenoxyacetic acid and 2,4-dichlorophenol mixture in saline solution using a falling-film solar reactor.

PubMed

Luna, Airton J; Nascimento, Cláudio A O; Foletto, Edson Luiz; Moraes, José E F; Chiavone-Filhoe, Osvaldo

2014-01-01

In this work, a saline aqueous solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a falling-film solar reactor. The influence of the parameters such as initial pH (5-7), initial concentration of Fe2+ (1-2.5mM) and rate of H202 addition (1.87-3.74mmol min-1) was investigated. The efficiency of photodegradation was determined from the removal of dissolved organic carbon (DOC), described by the species degradation of phenol, 2,4-D and 2,4-DCP. Response surface methodology was employed to assess the effects of the variables investigated, i.e. [Fe2+], [H202] and pH, in the photo-Fenton process with solar irradiation. The results reveal that the variables' initial concentration of Fe2+ and H202 presents predominant effect on pollutants' degradation in terms of DOC removal, while pH showed no influence. Under the most adequate experimental conditions, about 85% DOC removal was obtained in 180 min by using a reaction system employed here, and total removal of phenol, 2,4- and 2,4-DCP mixture in about 30min.

A new ultrahigh performance liquid chromatography with diode array detection coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry analytical strategy for fast analysis and improved characterization of phenolic compounds in apple products.

PubMed

Ramirez-Ambrosi, M; Abad-Garcia, B; Viloria-Bernal, M; Garmon-Lobato, S; Berrueta, L A; Gallo, B

2013-11-05

A new, rapid, selective and sensitive ultrahigh performance liquid chromatography with diode array detection coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (UHPLC-DAD-ESI-Q-ToF-MS) strategy using automatic and simultaneous acquisition of exact mass at high and low collision energy, MS(E), has been developed to obtain polyphenolic profile of apples, apple pomace and apple juice from Asturian cider apples in a single run injection of 22 min. MS(E) spectral data acquisition overcomes chromatographic co-elution problems, performing simultaneous collection of precursor ions as well as other ions produced as a result of their fragmentation, which allows resolving complex spectra from mixtures of precursor ions in an unsupervised way and eases their interpretation. Using this technique, 52 phenolic compounds of five different classes were readily characterized in these apple extracts in both positive and negative ionization modes. The spectral data for phenolic compounds obtained using this acquisition mode are comparable to those obtained by conventional LC-MS/MS as exemplified in this work. Among the 52 phenolic compounds identified in this work, 2 dihydrochalcones and 3 flavonols have been tentatively identified for the first time in apple products. Moreover, 2 flavanols, 4 dihydrochalcones, 9 hydroxycinnamic acids and 4 flavonols had not been previously reported in apple by ToF analysis to our knowledge. Copyright © 2013 Elsevier B.V. All rights reserved.

Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity.

PubMed

Kowol, Christian R; Nagy, Nóra V; Jakusch, Tamás; Roller, Alexander; Heffeter, Petra; Keppler, Bernhard K; Enyedy, Éva A

2015-11-01

The stoichiometry and thermodynamic stability of vanadium(IV/V) complexes of Triapine and two related α(N)-heterocyclic thiosemicarbazones (TSCs) with potential antitumor activity have been determined by pH-potentiometry, EPR and (51)V NMR spectroscopy in 30% (w/w) dimethyl sulfoxide/water solvent mixtures. In all cases, mono-ligand complexes in different protonation states were identified. Dimethylation of the terminal amino group resulted in the formation of vanadium(IV/V) complexes with considerably higher stability. Three of the most stable complexes were also synthesized in solid state and comprehensively characterized. The biological evaluation of the synthesized vanadium complexes in comparison to the metal-free ligands in different human cancer cell lines revealed only minimal influence of the metal ion. Thus, in addition the coordination ability of salicylaldehyde thiosemicarbazone (STSC) to vanadium(IV/V) ions was investigated. The exchange of the pyridine nitrogen of the α(N)-heterocyclic TSCs to a phenolate oxygen in STSC significantly increased the stability of the complexes in solution. Finally, this also resulted in increased cytotoxicity activity of a vanadium(V) complex of STSC compared to the metal-free ligand. Copyright © 2015 Elsevier Inc. All rights reserved.

A coumarin with an unusual structure from Cuphea ignea, its cytotoxicity and antioxidant activities.

PubMed

Moustafa, E S; Swilam, N F; Ghanem, O B; Hashim, A N; Nawwar, M A; Lindequist, U; Linscheid, M W

2018-04-02

Phenolic metabolite profiling using two dimensional paper chromatographic analysis (2 DPC) was used for assaying the complex mixture of phenolics of an aqueous ethanol aerial part extract of Cuphea ignea (Lytheraceae). A coumarin with a rare structure, namely, 7-hydroxy 3-methoxy coumarin 5-O-β-glucopyranoside was isolated from the investigated extract. The structure was elucidated by conventional methods and spectral analysis, including one and two dimensional NMR (1D and 2D NMR), as well as by interpretation of the spectra obtained by high resolution electrospray ionization mass technique (HRESIMS). The rare coumarin significantly inhibited reactive oxygen species production with an ED50 value of 6.31±1.64 μg/ml and 5.78±0.66 μg/ml as determined by the the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the oxygen radical absorption capacity (ORAC) assay respectively. The isolated coumarin presented a cytotoxic activity assessed by using the neutral red assay (NRU) against lung cancer cell line (H23) with IC50 of 40.38±2.75 μg/ml.

Interrelations between the mesomeric and electronegativity effects in para-substituted derivatives of phenol/phenolate and aniline/anilide H-bonded complexes: a DFT-based computational study.

PubMed

Szatyłowicz, Halina; Krygowski, Tadeusz M; Jezierska, Aneta; Panek, Jarosław J

2009-05-14

We were able to test the Bent-Walsh rule by examining geometric parameters in the vicinity of the ipso-carbon atom of H-bonded complexes of para-substituted phenol/phenolate and aniline/anilide derivatives for the three cases (i) a versus alpha, (ii) alpha versus d(CO) or d(CN), and (iii) a versus d(CO) or d(CN), where alpha is the ring valence angle at the ipso-carbon atom (C1 substituted by OH or O(-) or NH(2) or NH(-)) and a is the arithmetic mean of the two C(ipso)-C(ortho) bond lengths. The data for nonequilibrium H-bonded complexes of unsubstituted phenol/phenolate and aniline/anilide with the respective bases F(-) and CN(-) and acids HF and HCN showed the same dependence of a on d(CX) (X = O, N) as the data for equilibrium complexes of para-Y-substituted phenol/phenolate and aniline/anilide derivatives (Y = NO, NO(2), CHO, COMe, CONH(2), Cl, F, H, Me, OMe, OH) with the same bases and acids. The slope of these dependencies was negative, as expected. In the remaining cases (a versus alpha and alpha versus d(CO) or d(CN)), the slopes for simulated complexes followed the Bent-Walsh rule. Finally, for the equilibrium complexes in which the substituent effect was included, the slopes of the trend lines for the substituted systems were opposite. This is because in the a versus alpha relationships, electonegativity and the resonance effect act in the same direction, whereas for the other two cases, these effects are opposite, and the resonance effect dominates.

Scientific validation of synergistic antioxidant effects in commercialised mixtures of Cymbopogon citratus and Pterospartum tridentatum or Gomphrena globosa for infusions preparation.

PubMed

Roriz, Custódio Lobo; Barros, Lillian; Carvalho, Ana Maria; Santos-Buelga, Celestino; Ferreira, Isabel C F R

2015-10-15

Pterospartum tridentatum (L.) Willk., Gomphrena globosa L. and Cymbopogon citratus (DC) Stapf. are examples of medicinal plants with antioxidant properties on their own, but that can be improved when mixed. In the present work, the antioxidant activity and phenolic compounds were determined in the infusions prepared from the individual plants, and from mixtures of these plants in different proportions. P. tridentatum > C. citratus > G. globosa was the order observed for antioxidant efficacy, which can be related to their different composition in phenolic compounds. Synergism was the main effect observed among the tested mixtures, mainly for the infusions prepared from the plants in proportion 40%:60% (either P. tridentatum and C. citratus; or G. globosa and C. citratus). The infusion obtained with 40% of P. tridentatum and 60% of C. citratus gave the highest antioxidant properties. The present study validates the commercialisation of the studied plants combined in specific proportions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nonenzymic spectrophotometric determination of potential poison ivy cross-reactors.

PubMed

Quattrone, A J

1977-03-01

I describe an inexpensive, nonenzymic analytical system for prescreening substances that might cross-react as Rhus toxing (e.g., poison ivy, poison oak, and sumac allergens) on human skin. By spectrophotometric assay after incubation with an oxidizing mixture of Cu(II)ammine complex and ammonium persulfate, I could accurately and reproducibly determine o-quinoidal products of several potential synthetic cross-reactors and native poison ivy allergen, and could distinguish these from catecholamines, resorcinol, p-hydroquinone, and a closely related phenol. A good correlation was obtained between this nonenzymic technique and an enzymic assay. This Cu(II)ammine/persulfate oxidative assay, however, is inexpensive and obviates any spectral interference from enzymic proteins.

Essential Oils’ Chemical Characterization and Investigation of Some Biological Activities: A Critical Review

PubMed Central

Dhifi, Wissal; Bellili, Sana; Jazi, Sabrine; Bahloul, Nada; Mnif, Wissem

2016-01-01

This review covers literature data summarizing, on one hand, the chemistry of essential oils and, on the other hand, their most important activities. Essential oils, which are complex mixtures of volatile compounds particularly abundant in aromatic plants, are mainly composed of terpenes biogenerated by the mevalonate pathway. These volatile molecules include monoterpenes (hydrocarbon and oxygenated monoterpens), and also sesquiterpenes (hydrocarbon and oxygenated sesquiterpens). Furthermore, they contain phenolic compounds, which are derived via the shikimate pathway. Thanks to their chemical composition, essential oils possess numerous biological activities (antioxidant, anti-inflammatory, antimicrobial, etc…) of great interest in food and cosmetic industries, as well as in the human health field. PMID:28930135

Analysis of organic acids and phenols of interest in the wine industry using Langmuir-Blodgett films based on functionalized nanoparticles.

PubMed

Medina-Plaza, C; García-Cabezón, C; García-Hernández, C; Bramorski, C; Blanco-Val, Y; Martín-Pedrosa, F; Kawai, T; de Saja, J A; Rodríguez-Méndez, M L

2015-01-01

A chemically modified electrode consisting of Langmuir-Blodgett (LB) films of n-dodecanethiol functionalized gold nanoparticles (SDODAuNP-LB), was investigated as a voltammetric sensor of organic and phenolic acids of interest in the wine industry. The nanostructured films demonstrated interfacial properties being able to detect the main organic acids present in grapes and wines (tartaric, malic, lactic and citric). Compared to a bare ITO electrode, the modified electrodes exhibited a shift of the reduction potential in the less positive direction and a marked enhancement in the current response. Moreover, the increased electrocatalytic properties made it possible to distinguish between the different dissociable protons of polyprotic acids. The SDODAuNP-LB sensor was also able to provide enhanced responses toward aqueous solutions of phenolic acids commonly found in wines (caffeic and gallic acids). The presence of nanoparticles increased drastically the sensitivity toward organic acids and phenolic compounds. Limits of detection as low as 10(-6) mol L(-1) were achieved. Efficient catalytic activity was also observed in mixtures of phenolic acid/tartaric in the range of pHs typically found in wines. In such mixtures, the electrode was able to provide simultaneous information about the acid and the phenol concentrations with a complete absence of interferences. The excellent sensing properties shown by these sensors could be attributed to the electrocatalytic properties of the nanoparticles combined with the high surface to volume ratio and homogeneity provided by the LB technique used for the immobilization. Moreover, the LB technique also provided an accurate method to immobilize the gold nanoparticles giving rise to stable and reproducible sensors showing repeatability lower than 2% and reproducibility lower than 4% for all the compounds analyzed. Copyright © 2014. Published by Elsevier B.V.

Phenolic acids, hydrolyzable tannins, and antioxidant activity of geopropolis from the stingless bee Melipona fasciculata Smith.

PubMed

Dutra, Richard Pereira; Abreu, Bruno Vinicius de Barros; Cunha, Mayara Soares; Batista, Marisa Cristina Aranha; Torres, Luce Maria Brandão; Nascimento, Flavia Raquel Fernandes; Ribeiro, Maria Nilce Sousa; Guerra, Rosane Nassar Meireles

2014-03-26

Geopropolis is a mixture of plant resins, waxes, and soil produced by the stingless bee Melipona fasciculata Smith. This paper describes the antioxidant activity and chemical composition of geopropolis produced by M. fasciculata. The total phenolic content determined with the Folin-Ciocalteu reagent was highest in the ethyl acetate fraction and hydroalcoholic extract. Antioxidant activity was assayed by the in vitro DPPH, ABTS, and FRAP assays. The hydroalcoholic extract and fractions of geopropolis, except for the hexane fraction, exhibited antioxidant activity against DPPH, ABTS, and FRAP. The phenolic compounds were identified by HPLC-DAD-MS on the basis of the evaluation of their UV-vis absorption maxima (λmax) and mass spectral analysis. Eleven compounds belonging to the classes of phenolic acids and hydrolyzable tannins (gallotannins and ellagitannins) were tentatively identified. These compounds are responsible for the antioxidant activity and high phenolic content of geopropolis produced by M. fasciculata.

Transglycosylation reactions, a main mechanism of phenolics incorporation in coffee melanoidins: Inhibition by Maillard reaction.

PubMed

Moreira, Ana S P; Nunes, Fernando M; Simões, Cristiana; Maciel, Elisabete; Domingues, Pedro; Domingues, M Rosário M; Coimbra, Manuel A

2017-07-15

Under roasting conditions, polysaccharides depolymerize and also are able to polymerize, forming new polymers through non-enzymatic transglycosylation reactions (TGRs). TGRs can also occur between carbohydrates and aglycones, such as the phenolic compounds present in daily consumed foods like coffee. In this study, glycosidically-linked phenolic compounds were quantified in coffee melanoidins, the polymeric nitrogenous brown-colored compounds formed during roasting, defined as end-products of Maillard reaction. One third of the phenolics present were in glycosidically-linked form. In addition, the roasting of solid-state mixtures mimicking coffee beans composition allowed the conclusion that proteins play a regulatory role in TGRs extension and, consequently, modulate melanoidins composition. Overall, the results obtained showed that TGRs are a main mechanism of phenolics incorporation in melanoidins and are inhibited by amino groups through Maillard reaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Identification of migrants from nitrile-butadiene rubber gloves].

PubMed

Mutsuga, Motoh; Kawamura, Yoko; Wakui, Chiseko; Maitani, Tamio

2003-04-01

Polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate are restricted for food contact use. In their place, disposable gloves made from nitrile-butadiene rubber (NBR) are used in contact with foodstuffs. Some unknown substances were found to migrate into n-heptane from NBR gloves. By GC/MS, HR-MS and NMR, their chemical structures were confirmed to be 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (used as a plasticizer), 4,4'-butylidenedi(6-tert-butyl-m-cresol), a mixture of styrenated phenols consisting of 2-(alpha-methylbenzyl)phenol, 4-(alpha-methylbenzyl)phenol, 2,6-di(alpha-methylbenzyl)phenol, 2,4-di(alpha-methylbenzyl)phenol and 2,4,6-tri(alpha-methylbenzyl)phenol (used as antioxidants), and 2,4-di-tert-butylphenol, which seems to a degradation product of antioxidant. Migration levels of these compounds were 1.68 micrograms/cm2 of 2,4-di-tert-butylphenol, 2.80 micrograms/cm2 of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 46.08 micrograms/cm2 of styrenated phenols and 4.22 micrograms/cm2 of 4,4'-butylidenedi(6-tert-butyl-m-cresol) into n-heptane, respectively. The content of total styrenated phenols was 6,900 micrograms/g in NBR gloves.

Microwave-assisted co-pyrolysis of brown coal and corn stover for oil production.

PubMed

Zhang, Yaning; Fan, Liangliang; Liu, Shiyu; Zhou, Nan; Ding, Kuan; Peng, Peng; Anderson, Erik; Addy, Min; Cheng, Yanling; Liu, Yuhuan; Li, Bingxi; Snyder, John; Chen, Paul; Ruan, Roger

2018-07-01

The controversial synergistic effect between brown coal and biomass during co-pyrolysis deserves further investigation. This study detailed the oil production from microwave-assisted co-pyrolysis of brown coal (BC) and corn stover (CS) at different CS/BC ratios (0, 0.33, 0.50, 0.67, and 1) and pyrolysis temperatures (500, 550, and 600 °C). The results showed that a higher CS/BC ratio resulted in higher oil yield, and a higher pyrolysis temperature increased oil yield for brown coal and coal/corn mixtures. Corn stover and brown coal showed different pyrolysis characteristics, and positive synergistic effect on oil yield was observed only at CS/BC ratio of 0.33 and pyrolysis temperature of 600 °C. Oils from brown coal mainly included hydrocarbons and phenols whereas oils from corn stover and coal/corn mixtures were dominated by ketones, phenols, and aldehydes. Positive synergistic effects were observed for ketones, aldehydes, acids, and esters whereas negative synergistic effects for hydrocarbons, phenols and alcohols. Copyright © 2018 Elsevier Ltd. All rights reserved.

Intercostal nerve blockade with a mixture of bupivacaine and phenol enhance the efficacy of intravenous patient-controlled analgesia in the control of post-cholecystectomy pain.

PubMed

Maidatsi, P; Gorgias, N; Zaralidou, A; Ourailoglou, V; Giala, M

1998-09-01

Prolonged nerve conduction blockade has been proposed to result from the summed effects of charged and neutral local anaesthetics. Thirty-seven patients were randomly allocated to receive intravenous patient-controlled analgesia alone or combined with intercostal blockade (T7-T11) with a mixture of 0.45% bupivacaine and 0.6% phenol for post-cholecystectomy analgesia. Adequacy of pain relief was measured by patient scores on a 10-cm visual analogue scale and by dose-demand ratio, amounts of loading dose and total consumption of morphine and also the duration of patient-controlled analgesia in each group. No differences were found between groups in post-operative scores, dose-demand ratios and loading doses of morphine. However, in the combined treatment group, a significantly lower total consumption of morphine (P < 0.05), associated with a shorter duration of patient-controlled analgesia (P < 0.02) and a decreased mean number of unsuccessful demands (P < 0.001) were recorded. Intercostal blockade with bupivacaine-phenol supplements intravenous patient-controlled analgesia for post-cholecystectomy pain relief.

Role of Hydrogen Bonding in Photoinduced Electron-Proton Transfer from Phenols to a Polypyridine Ru Complex with a Proton-Accepting Ligand

DOE PAGES

Lymar, Sergei V.; Ertem, Mehmed Z.; Lewandowska-Andralojc, Anna; ...

2017-08-09

Electron-proton transfer, EPT, from phenols to a triplet MLCT-excited Ru polypyridine complex containing an uncoordinated nitrogen site, 1(T), can be described by a kinetic model that accounts for the H-bonding of 1(T) to phenol, 1(T) to solvent, and phenol to solvent. The latter plays a major role in the kinetic solvent effect and commonly precludes simultaneous determination of the EPT rate constant and 1(T)-phenol H-bonding constant. A number of these quantities previously reported for similar systems are shown to be in error due to an inconsistent data analysis. In conclusion, control experiments replacing either 1(T) by its structural isomer withmore » a sterically screened nitrogen site or phenol by its H-bonding surrogate, trifluoroethanol, and the observation of negative activation enthalpies for the overall reactions between 1(T) and phenols lend support to the proposed model and provide evidence for the formation of a precursor H-bonded complex between the reactants, which is a prerequisite for EPT.« less

Role of Hydrogen Bonding in Photoinduced Electron-Proton Transfer from Phenols to a Polypyridine Ru Complex with a Proton-Accepting Ligand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lymar, Sergei V.; Ertem, Mehmed Z.; Lewandowska-Andralojc, Anna

Electron-proton transfer, EPT, from phenols to a triplet MLCT-excited Ru polypyridine complex containing an uncoordinated nitrogen site, 1(T), can be described by a kinetic model that accounts for the H-bonding of 1(T) to phenol, 1(T) to solvent, and phenol to solvent. The latter plays a major role in the kinetic solvent effect and commonly precludes simultaneous determination of the EPT rate constant and 1(T)-phenol H-bonding constant. A number of these quantities previously reported for similar systems are shown to be in error due to an inconsistent data analysis. In conclusion, control experiments replacing either 1(T) by its structural isomer withmore » a sterically screened nitrogen site or phenol by its H-bonding surrogate, trifluoroethanol, and the observation of negative activation enthalpies for the overall reactions between 1(T) and phenols lend support to the proposed model and provide evidence for the formation of a precursor H-bonded complex between the reactants, which is a prerequisite for EPT.« less

Isolation of strawberry anthocyanins using high-speed counter-current chromatography and the copigmentation with catechin or epicatechin by high pressure processing.

PubMed

Zou, Hui; Ma, Yan; Xu, Zhenzhen; Liao, Xiaojun; Chen, Ailiang; Yang, Shuming

2018-05-01

Three anthocyanins were isolated from strawberry extract by high-speed counter-current chromatography, using a biphasic mixture of tert-butyl methyl ether, n-butanol, acetonitrile, water and trifluoroacetic acid (2.5:2.0:2.5:5.0:1.0%). The anthocyanins were identified as pelargonidin-3-rutinoside, cyanidin-3-glucoside and pelargonidin-3-glucoside with purity of 95.6%, 96.2% and 99.3% respectively. Additionally, the copigmentation reaction rates between pelargonidin-3-glucoside and phenolic acids (catechin or epicatechin) at pH 1.5 and 3.6, pressure 0.1 and 500 MPa, and temperature 60 °C were calculated. The absorbance of pelargonidin-3-glucoside at pH 3.6, with high quantity of phenolic acids was significantly increased by high pressure. The complex of pelargonidin-3-glucoside/catechin has a binding energy of 78.64 kJ/mol at pH 3.6, and 39.13 kJ/mol at pH 1.5; pelargonidin-3-glucoside/epicatechin has a binding energy of 75.34 kJ/mol at pH 1.5 and 54.47 kJ/mol at pH 3.6. The hydrogen bond and van der Waals interaction were the main forces contributing to the structures of complex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Supercritical-assistant liquid crystal template approach to synthesize mesoporous titania/multiwalled carbon nanotube composites with high visible-light driven photocatalytic performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chen; Li, Youji, E-mail: bcclyj@163.com; Xu, Peng

2014-12-15

Graphical abstract: We investigate the influence of mesoporous titania content upon the visible-light driven photocatalytic performance of MPT/MWCNTs in phenol degradation. - Highlights: • MPT/MWCNTs were fabricated by liquid-crystal template in supercritical CO{sub 2}. • MPT/MWCNTs show high visible-light driven photoactivity for phenol degradation. • MPT/MWCNTs also show high reusable photoactivity under visible irradiation. • MPT content can control visible-light driven photoactivity of MPT/MWCNTs. • MPT is not easily broken away from from MPT/MWCNT composites. - Abstract: Mesoporous titania (MPT) was deposited onto multiwalled carbon nanotubes (MWCNTs) by deposition of titanium sol containing liquid-crystal template with assistant of supercritical CO{submore » 2}. The products were characterized with various analytical techniques to determine their structural, morphological, optical absorption and photocatalytic properties. The results indicate that in photocatalytic degradation of phenol under visible light, the mixtures or composites of MPT and MWCNT show the high efficiency because of synergies between absorbing visible light, releasing electrons and facilitating transfer of charge carriers of MWCNTs and providing activated centers of MPT. Because of the mutual constraint between MPT and MWCNTs on the photocatalytic efficiency, the optimal loading of MPT in MPT/MWCNT-3 for phenol degradation is 48%. Because the intimate contact between MWCNTs and MPT is more beneficial to electron transformation, photoactivity of mixture is lower than that of composites with high reusable performance. The optimum conditions of phenol degradation were obtained.« less

Ultrastrong Graphene-Based Fibers with Increased Elongation.

PubMed

Li, Mochen; Zhang, Xiaohong; Wang, Xiang; Ru, Yue; Qiao, Jinliang

2016-10-12

A new method to prepare graphene-based fibers with ultrahigh tensile strength, conductivity, and increased elongation is reported. It includes wet-spinning the mixture of GO aqueous dispersion with phenolic resin solution in a newly developed coagulation bath, followed by annealing. The introduced phenolic carbon increased densification of graphene fibers through reducing defects and increased interfacial interaction among graphene sheets by forming new C-C bonds, thus resulting in the increasing of stiffness, toughness, and conductivity simultaneously.

Isolation of four phenolic compounds from Mangifera indica L. flowers by using normal phase combined with elution extrusion two-step high speed countercurrent chromatography.

PubMed

Shaheen, Nusrat; Lu, Yanzhen; Geng, Ping; Shao, Qian; Wei, Yun

2017-03-01

Two-step high speed countercurrent chromatography method, following normal phase and elution-extrusion mode of operation by using selected solvent systems, was introduced for phenolic compounds separation. Phenolic compounds including gallic acid, ethyl gallate, ethyl digallate and ellagic acid were separated from the ethanol extract of mango (Mangifera indica L.) flowers for the first time. In the first step, gallic acid of 3.7mg and ethyl gallate of 3.9mg with the purities of 98.87% and 99.55%, respectively, were isolated by using hexane-ethylacetate-methanol-water (4:6:4:6, v/v) in normal phase high speed countercurrent chromatography from 200mg of crude extract, while ethyl digallate and ellagic acid were collected in the form of mixture fraction. In the second step, further purification of the mixture was carried out with the help of another selected solvent system of dichloromethane-methanol-water (4:3:2, v/v) following elusion-extrusion mode of operation. Ethyl digallate of 3.8mg and ellagic acid of 5.7mg were separated well with high purities of 98.68% and 99.71%, respectively. The separated phenolic compounds were identified and confirmed by HPLC, UPLC-QTOF/ESI-MS, 1 H and 13 C NMR spectrometric analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

On the origin of donor O–H bond weakening in phenol-water complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Pujarini; Mukhopadhyay, Deb Pratim; Chakraborty, Tapas, E-mail: pctc@iacs.res.in

2015-11-28

Matrix isolation infrared spectroscopy has been used to investigate intermolecular interactions in a series of binary O–H⋯O hydrogen bonded phenol-water complexes where water is the common acceptor. The interaction at the binding site has been tuned by incorporating multiple fluorine substitutions at different aromatic ring sites of the phenol moiety. The spectral effects for the aforesaid chemical changes are manifested in the infrared spectra of the complexes as systematic increase in spectral shift of the phenolic O–H stretching fundamental (Δν{sub O–H}). While ν{sub O–H} bands of the monomers of all the fluorophenols appear within a very narrow frequency range, themore » increase in Δν{sub O–H} of the complexes from phenol to pentafluorophenol is very large, nearly 90%. The observed values of Δν{sub O–H} do not show a linear correlation with the total binding energies (ΔE{sub b}) of the complexes, expected according to Badger-Bauer rule. However, in the same Δν{sub O–H} vs ΔE{sub b} plot, nice linear correlations are revealed if the complexes of ortho-fluorophenols are treated separately from their meta/para-substituted analogues. The observations imply that in spite of having the same binding site (O–H⋯O) and the same chemical identities (phenolic), the complexes of ortho and non-ortho fluorophenols do not belong, from the viewpoint of detailed molecular interactions, to a homologous series. Linear correlations of Δν{sub O–H} are, however, observed with respect to the electrostatic component of ΔE{sub b} as well as the quantum mechanical charge transfer interaction energy (E{sub CT}). From quantitative viewpoint, the latter correlation along with the associated electronic structure parameters appears more satisfactory. It has also been noted that the observed Δν{sub O–H} values of the complexes display a linear relationship with the aqueous phase pK{sub a} values of the respective phenol derivatives.« less

Chemistry of Secondary Polyphenols Produced during Processing of Tea and Selected Foods

PubMed Central

Tanaka, Takashi; Matsuo, Yosuke; Kouno, Isao

2010-01-01

This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone–phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing. PMID:20161999

Complex Mixture-Associated Hormesis and Toxicity: The Case of Leather Tanning Industry

PubMed Central

Pagano, Giovanni; Castello, Giuseppe; Gallo, Marialuisa; Borriello, Ilaria; Guida, Marco

2008-01-01

A series of studies investigated the toxicities of tannery-derived complex mixtures, i.e. vegetable tannin (VT) from Acacia sp. or phenol-based synthetic tannin (ST), and waste-water from tannin-based vs. chromium-based tanneries. Toxicity was evaluated by multiple bioassays including developmental defects and loss of fertilization rate in sea urchin embryos and sperm (Paracentrotus lividus and Sphaerechinus granularis), and algal growth inhibition (Dunaliella tertiolecta and Selenastrum capricornutum). Both VT and ST water extracts resulted in hormetic effects at concentrations ranging 0.1 to 0.3%, and toxicity at levels ≥1%, both in sea urchin embryo and sperm, and in algal growth bioassays. When comparing tannin-based tannery wastewater (TTW) vs. chromium-based tannery effluent (CTE), a hormesis to toxicity trend was observed for TTW both in terms of developmental and fertilization toxicity in sea urchins, and in algal growth inhibition, with hormetic effects at 0.1 to 0.2% TTW, and toxicity at TTW levels ≥1%. Unlike TTW, CTE showed a monotonic toxicity increase from the lowest tested level (0.1%) and CTE toxicity at higher levels was significantly more severe than TTW-induced toxicity. The results support the view that leather production utilizing tannins might be regarded as a more environmentally friendly procedure than chromium-based tanning process. PMID:19088903

Complex mixture-associated hormesis and toxicity: the case of leather tanning industry.

PubMed

Pagano, Giovanni; Castello, Giuseppe; Gallo, Marialuisa; Borriello, Ilaria; Guida, Marco

2008-01-01

A series of studies investigated the toxicities of tannery-derived complex mixtures, i.e. vegetable tannin (VT) from Acacia sp. or phenol-based synthetic tannin (ST), and waste-water from tannin-based vs. chromium-based tanneries. Toxicity was evaluated by multiple bioassays including developmental defects and loss of fertilization rate in sea urchin embryos and sperm (Paracentrotus lividus and Sphaerechinus granularis), and algal growth inhibition (Dunaliella tertiolecta and Selenastrum capricornutum). Both VT and ST water extracts resulted in hormetic effects at concentrations ranging 0.1 to 0.3%, and toxicity at levels > or =1%, both in sea urchin embryo and sperm, and in algal growth bioassays. When comparing tannin-based tannery wastewater (TTW) vs. chromium-based tannery effluent (CTE), a hormesis to toxicity trend was observed for TTW both in terms of developmental and fertilization toxicity in sea urchins, and in algal growth inhibition, with hormetic effects at 0.1 to 0.2% TTW, and toxicity at TTW levels > or =1%. Unlike TTW, CTE showed a monotonic toxicity increase from the lowest tested level (0.1%) and CTE toxicity at higher levels was significantly more severe than TTW-induced toxicity. The results support the view that leather production utilizing tannins might be regarded as a more environmentally friendly procedure than chromium-based tanning process.

Inhibition of cholinesterase activity by extracts, fractions and compounds from Calceolaria talcana and C. integrifolia (Calceolariaceae: Scrophulariaceae).

PubMed

Cespedes, Carlos L; Muñoz, Evelyn; Salazar, Juan R; Yamaguchi, Lydia; Werner, Enrique; Alarcon, Julio; Kubo, Isao

2013-12-01

Extracts, fractions and compounds from Calceolaria talcana and C. integrifolia exhibited strong inhibitory effects of the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes using the in vitro Ellman's method. The most active samples were from the ethyl acetate extract, which caused a mixed-type inhibition against AChE (69.8% and 79.5% at 100 and 200 μg/ml, respectively) and against BChE (98.5% and 99.8% at 100 and 200 μg/ml, respectively) and its major components verbascoside 8 (50.9% and 70.0% at 200 μg/ml, against AChE and BChE, respectively), martynoside 9, and fraction F-7 (which corresponds to a mixture of 8, 9, and other phenylethanoids and phenolics that remain unidentified) (80.2% and 85.3% at 100 and 200 μg/ml, against AChE, respectively and 99.1% and 99.7% at 100 and 200 μg/ml, against BChE, respectively) inhibited the acetylcholinesterase enzyme competitively. The most polar fraction F-5 from n-hexane extract (a mixture of naphthoquinones: 2-hydroxy-3-(1,1-dimethylallyl-1,4-naphthoquinone) 6, α-dunnione 7 and other polar compounds that remain unidentified) showed a mixed-type inhibition (71.5% and 72.1% against AChE and BChE at 200 μg/ml, respectively). Finally, the methanol-soluble residue presented a complex, mixed-type inhibition (39.9% and 67.9% against AChE and BChE at 200 μg/ml, respectively). The mixture F-3 with diterpenes was obtained from the n-hexane extract: (1,10-cyclopropyl-9-epi-ent-isopimarol) 1, 19-α-hydroxy-abietatriene 2, and F-4 a mixture of triterpenes α-lupeol 3, β-sitosterol 4, ursolic acid 5 together with a complex mixture of terpenes that did not show activity. In summary, extracts and natural compounds from C. talcana and C. integrifolia were isolated, identified and characterized as cholinesterase inhibitors.

Phenols and the antioxidant capacity of Mediterranean vegetables prepared with extra virgin olive oil using different domestic cooking techniques.

PubMed

Ramírez-Anaya, Jessica Del Pilar; Samaniego-Sánchez, Cristina; Castañeda-Saucedo, Ma Claudia; Villalón-Mir, Marina; de la Serrana, Herminia López-García

2015-12-01

Potato, tomato, eggplant and pumpkin were deep fried, sautéed and boiled in Mediterranean extra virgin olive oil (EVOO), water, and a water/oil mixture (W/O). We determined the contents of fat, moisture, total phenols (TPC) and eighteen phenolic compounds, as well as antioxidant capacity in the raw vegetables and compared these with contents measured after cooking. Deep frying and sautéing led to increased fat contents and TPC, whereas both types of boiling (in water and W/O) reduced the same. The presence of EVOO in cooking increased the phenolics identified in the raw foods as oleuropein, pinoresinol, hydroxytyrosol and tyrosol, and the contents of vegetable phenolics such as chlorogenic acid and rutin. All the cooking methods conserved or increased the antioxidant capacity measured by DPPH, FRAP and ABTS. Multivariate analyses showed that each cooked vegetable developed specific phenolic and antioxidant activity profiles resulting from the characteristics of the raw vegetables and the cooking techniques. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mixed Phenolic Acids Mediated Proliferation of Pathogens Talaromyces helicus and Kosakonia sacchari in Continuously Monocultured Radix pseudostellariae Rhizosphere Soil

PubMed Central

Wu, Hongmiao; Wu, Linkun; Wang, Juanying; Zhu, Quan; Lin, Sheng; Xu, Jiahui; Zheng, Cailiang; Chen, Jun; Qin, Xianjin; Fang, Changxun; Zhang, Zhixing; Azeem, Saadia; Lin, Wenxiong

2016-01-01

Radix pseudostellariae L. is a common and popular Chinese medication. However, continuous monoculture has increased its susceptibility to severe diseases. We identified two pathogenic microorganisms, Talaromyces helicus M. (KU355274) and Kosakonia sacchari W. (KU324465), and their antagonistic bacterium, Bacillus pumilus Z. in rhizosphere soil of continuously monocultured R. pseudostellariae. Nine types of phenolic acids were identified both in the rhizosphere soil and in culture medium under sterile conditions. A syringic acid and phenolic acid mixture significantly promoted the growth of T. helicus and K. sacchari. T. helicus could utilize eight types of phenolic acids, whereas K. sacchari could only use four phenolic acids. K. sacchari produced protocatechuic acid when consuming vanillin. Protocatechuic acid negatively affected the growth of B. pumilus. The 3A-DON toxin produced by T. helicus promoted the growth of K. sacchari and inhibited growth of B. pumilus at low concentrations. These data help explain why phenolic exudates mediate a microflora shift and structure disorder in the rhizosphere soil of continuously monocultured R. pseudostellariae and lead to increased replanting disease incidence. PMID:27014250

A Phenolic Extract Obtained from Methyl Jasmonate-Treated Strawberries Enhances Apoptosis in a Human Cervical Cancer Cell Line.

PubMed

Spagnuolo, Carmela; Flores, Gema; Russo, Gian Luigi; Ruiz Del Castillo, Maria Luisa

2016-10-01

In the present study, we evaluated the effect of methyl jasmonate (MeJA) treatment on strawberry phenolic composition. Strawberry extracts contain a mixture of phenolic compounds possessing several biological properties. We demonstrated that these extracts were more effective in inducing apoptosis in HeLa cells compared to phenolic preparations derived from untreated strawberries. Treatment of strawberries with 0.5% MeJA resulted in increased polyphenols content (from 7.4 to 8.6 mM quercetin equivalents) and antioxidant properties (from 3.9 to 4.6 mM quercetin equivalents). The identification and quantification of phenolic compounds by liquid chromatography-mass spectrometry in the strawberry extracts showed that cyanidin glucoside, pelargonidin glucoside, and ellagic glucoside acid were significantly higher in strawberries treated with MeJA. Phenolic extracts from MeJA-treated strawberries significantly decreased the cell viability in HeLa cells, compared to extracts derived from untreated fruits. We hypothesized that the enhanced apoptotic activity of MeJA-treated strawberries was due to a synergistic or additive effect of different phenolic compounds present in the extract, rather than the activity of a single molecule.

A peroxynitrite complex of copper: formation from a copper-nitrosyl complex, transformation to nitrite and exogenous phenol oxidative coupling or nitration.

PubMed

Park, Ga Young; Deepalatha, Subramanian; Puiu, Simona C; Lee, Dong-Heon; Mondal, Biplab; Narducci Sarjeant, Amy A; del Rio, Diego; Pau, Monita Y M; Solomon, Edward I; Karlin, Kenneth D

2009-11-01

Reaction of nitrogen monoxide with a copper(I) complex possessing a tridentate alkylamine ligand gives a Cu(I)-(*NO) adduct, which when exposed to dioxygen generates a peroxynitrite (O=NOO(-))-Cu(II) species. This undergoes thermal transformation to produce a copper(II) nitrito (NO(2) (-)) complex and 0.5 mol equiv O(2). In the presence of a substituted phenol, the peroxynitrite complex effects oxidative coupling, whereas addition of chloride ion to dissociate the peroxynitrite moiety instead leads to phenol ortho nitration. Discussions include the structures (including electronic description) of the copper-nitrosyl and copper-peroxynitrite complexes and the formation of the latter, based on density functional theory calculations and accompanying spectroscopic data.

Extraction of phenol in wastewater with annular centrifugal contactors.

PubMed

Xu, Jin-Quan; Duan, Wu-Hua; Zhou, Xiu-Zhu; Zhou, Jia-Zhen

2006-04-17

Solvent extraction is an effective way to treat and recover the phenolic compounds from the high content phenolic wastewater at present. The experimental study on treating the wastewater containing phenol has been carried out with QH-1extractant (the amine mixture) and annular centrifugal contactors. The distribution ratio of phenol was 108.6 for QH-1-phenol system. The mass-transfer process of phenol for the system was mainly controlled by diffusion. When the flow ratio (aqueous/organic) was changed from 1/1 to 4/1, the rotor speed was changed from 2500 to 4000 r/min, and the total flow of two phases was changed from 20 to 70 mL/min, the mass-transfer efficiency E of the single-stage centrifugal contactor was more than 95%. When the flow ratio was changed from 4.4/1 to 4.9/1, the rotor speed was 3000 r/min, and the total flow of two phases was changed from 43.0 to 47.0 mL/min, the extraction rate rho of the three-stage cascade was more than 99%. When 15% NaOH was used for stripping of phenol in QH-1, the stripping efficiency of the three-stage cascade was also more than 99% under the experimental conditions.

The effect of water on the thermal expansion behavior of FM5055 carbon phenolic

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

1995-01-01

The effect of water on the thermal expansion behavior of FM5055 carbon phenolic is studied using a theory of mixtures approach. A partial pressure expression for the water constituent was obtained based upon certain assumptions regarding the thermodynamic state of water as it resides in the free volumes of the polymer. A simple constitutive model is used to simulate the polymer strain due to the application of the partial pressure of water. The resulting theory is applied to model the effect of moisture on the thermal expansion of FM5055 carbon phenolic specimens. The application of the theory results in calculated strains which were in close agreement with the measured strains.

Enzymatic electrochemical detection coupled to multivariate calibration for the determination of phenolic compounds in environmental samples.

PubMed

Hernandez, Silvia R; Kergaravat, Silvina V; Pividori, Maria Isabel

2013-03-15

An approach based on the electrochemical detection of the horseradish peroxidase enzymatic reaction by means of square wave voltammetry was developed for the determination of phenolic compounds in environmental samples. First, a systematic optimization procedure of three factors involved in the enzymatic reaction was carried out using response surface methodology through a central composite design. Second, the enzymatic electrochemical detection coupled with a multivariate calibration method based in the partial least-squares technique was optimized for the determination of a mixture of five phenolic compounds, i.e. phenol, p-aminophenol, p-chlorophenol, hydroquinone and pyrocatechol. The calibration and validation sets were built and assessed. In the calibration model, the LODs for phenolic compounds oscillated from 0.6 to 1.4 × 10(-6) mol L(-1). Recoveries for prediction samples were higher than 85%. These compounds were analyzed simultaneously in spiked samples and in water samples collected close to tanneries and landfills. Published by Elsevier B.V.

Understanding the degree of condensation of phenolic and etherified C-9 units of in situ lignins.

PubMed

Nanayakkara, Bernadette; Manley-Harris, Merilyn; Suckling, Ian D

2011-12-14

A novel approach for the quantification of the degree of condensation at the C(5) position of etherified and phenolic phenylpropane (C-9) units of in situ lignin is described. This is achieved by degrading unmethylated and methylated wood by thioacidolysis and analyzing the resultant product mixtures by quantitative (31)P NMR spectroscopy. Applying this new method to compression wood and normal wood from Pinus radiata showed that, whereas 41-47% of etherified guaiacyl C-9 units are condensed at the C(5) position, almost all phenolic guaiacyl C-9 units exist as uncondensed moieties. Analysis of milled wood lignin (MWL) isolated from the same wood by (31)P NMR spectroscopy before and after thioacidolysis showed that the phenolic guaiacyl C-9 units were more condensed than those in the in situ lignin. This is likely due to partial cleavage of the more condensed etherified linkages during the lignin isolation, leading to a relative increase in condensed phenolic guaiacyl C-9 units.

Acidolysis of p-coumaric acid with omega-3 oils and antioxidant activity of phenolipid products in in vitro and biological model systems.

PubMed

Wang, Jiankang; Shahidi, Fereidoon

2014-01-15

Lipase-catalyzed acidolysis of p-coumaric acid with seal blubber oil (SBO) and menhaden oil (MHO) was carried out, followed by identification of major phenolipids in the resultant acidolysis mixture using high-performance liquid chromatography/mass spectrometry. Separation of phenolipid components from the resultant acidolysis mixture was achieved using flash column chromatography. The antioxidant activities of the phenolipids were examined in in vitro assays and biological model systems. The major phenolipids identified from acidolysis mixtures with both SBO and MHO included eight phenolic monoacylglycerols and eight phenolic diacylglycerols. Phenolipids derived from SBO and MHO generally showed good antioxidant potential in the systems tested. The prepared phenolipids exhibited high scavenging capacity toward 1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radicals and displayed reducing power, strong inhibitory effect on bleaching of β-carotene, human low-density lipoprotein (LDL) cholesterol oxidation, as well as radical-induced DNA cleavage, thus suggesting that phenolipids derived from omega-3 oils may be used as potential stable products for health promotion and disease risk reduction.

Molecular recognition in the gas phase: benzocaine-phenol as a model of anaesthetic-receptor interaction.

PubMed

Aguado, Edurne; León, Iker; Cocinero, Emilio J; Lesarri, Alberto; Fernández, José A; Castaño, Fernando

2009-12-28

The benzocaine-phenol complex is proposed as a model system of the interaction between the local anaesthetic benzocaine and the tyrosine residue. The complex has been generated by supersonic expansion of benzocaine and phenol in helium and probed by 1- and 2-color mass-resolved laser spectroscopies. The electronic excitation spectrum of the 1 : 1 complex spans some approximately 700 cm(-1) and includes well resolved bands from at least two isomers, as demonstrated using UV-UV hole burning spectroscopy. The combination of ion dip infrared spectroscopy (IDIRS) and ab initio calculations shows that both isomers are stabilized by an OH...N hydrogen bond between the phenol hydroxyl group and the benzocaine amino moiety, differing only in the conformation adopted by the benzocaine monomer (trans and gauche). The application of the fragmentation threshold method to benzocaine-phenol suggests the existence of chemical reactions in the electronic excited state of the complex and/or in the ion. Such hypothesis is also supported by the calculated potential energy curves along the hydrogen bond coordinate.

Effect of solvent on the extraction of phenolic compounds and antioxidant capacity of hazelnut kernel.

PubMed

Fanali, Chiara; Tripodo, Giusy; Russo, Marina; Della Posta, Susanna; Pasqualetti, Valentina; De Gara, Laura

2018-03-22

Hazelnut kernel phenolic compounds were recovered applying two different extraction approaches, namely ultrasound-assisted solid/liquid extraction (UA-SLE) and solid-phase extraction (SPE). Different solvents were tested evaluating total phenolic compounds and total flavonoids contents together to antioxidant activity. The optimum extraction conditions, in terms of the highest value of total phenolic compounds extracted together to other parameters like simplicity and cost were selected for method validation and individual phenolic compounds analysis. The UA-SLE protocol performed using 0.1 g of defatted sample and 15 mL of extraction solvent (1 mL methanol/1 mL water/8 mL methanol 0.1% formic acid/5 mL acetonitrile) was selected. The analysis of hazelnut kernel individual phenolic compounds was obtained by HPLC coupled with DAD and MS detections. Quantitative analysis was performed using a mixture of six phenolic compounds belonging to phenolic classes' representative of hazelnut. Then, the method was fully validated and the resulting RSD% values for retention time repeatability were below 1%. A good linearity was obtained giving R 2 no lower than 0.997.The accuracy of the extraction method was also assessed. Finally, the method was applied to the analysis of phenolic compounds in three different hazelnut kernel varieties observing a similar qualitative profile with differences in the quantity of detected compounds. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fourier transform infrared spectroscopy as a metabolite fingerprinting tool for monitoring the phenotypic changes in complex bacterial communities capable of degrading phenol.

PubMed

Wharfe, Emma S; Jarvis, Roger M; Winder, Catherine L; Whiteley, Andrew S; Goodacre, Royston

2010-12-01

The coking process produces great volumes of wastewater contaminated with pollutants such as cyanides, sulfides and phenolics. Chemical and physical remediation of this wastewater removes the majority of these pollutants; however, these processes do not remove phenol and thiocyanate. The removal of these compounds has been effected during bioremediation with activated sludge containing a complex microbial community. In this investigation we acquired activated sludge from an industrial bioreactor capable of degrading phenol. The sludge was incubated in our laboratory and monitored for its ability to degrade phenol over a 48 h period. Multiple samples were taken across the time-course and analysed by Fourier transform infrared (FT-IR) spectroscopy. FT-IR was used as a whole-organism fingerprinting approach to monitor biochemical changes in the bacterial cells during the degradation of phenol. We also investigated the ability of the activated sludge to degrade phenol following extended periods (2-131 days) of storage in the absence of phenol. A reduction was observed in the ability of the microbial community to degrade phenol and this was accompanied by a detectable biochemical change in the FT-IR fingerprint related to cellular phenotype of the microbial community. In the absence of phenol a decrease in thiocyanate vibrations was observed, reflecting the ability of these communities to degrade this substrate. Actively degrading communities showed an additional new band in their FT-IR spectra that could be attributed to phenol degradation products from the ortho- and meta-cleavage of the aromatic ring. This study demonstrates that FT-IR spectroscopy when combined with chemometric analysis is a very powerful high throughput screening approach for assessing the metabolic capability of complex microbial communities. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Effect of the substituent and hydrogen bond on the geometry and electronic properties of OH and O(-) groups in para-substituted phenol and phenolate derivatives.

PubMed

Szatylowicz, Halina; Krygowski, Tadeusz M

2010-10-14

Interrelations between intra- and intermolecular interactions were analyzed by using computational modeling of the para-X-substituted derivatives of phenol and phenolate (where X = NO, NO(2), CHO, COMe, COOH, CONH(2), Cl, F, H, Me, OMe, and OH) and their equilibrium H-bonded complexes with HB and B(-) (where HB = HF and HCN and B(-) = F(-) and CN(-)). B3LYP/6-311++G** computation was applied. Both the substituent effect and H-bonding changed the electronic properties of the -O(-) and -OH groups and geometric parameters of phenol and phenolate derivatives and their H-bonded complexes. C-O bond lengths and aromaticity indices of the ring were found to depend linearly on σ(p)(-) of the substituents. In the first case the greatest sensitivity on the substituent effect was for 4-X-C(6)H(4)OH···CN(-) and 4-X-C(6)H(4)O(-)···HF complexes, whereas for 4-X-C(6)H(4)O(-)···HCN systems it was comparable with that for phenol derivatives and a little smaller than that for 4-X-C(6)H(4)O(-) derivatives. This means that the strength of H-bonding may considerably change the sensitivity of the C-O bond length to the substituent effect. The greatest sensitivity of the aromaticity indices, both HOMA and NICS(1)zz, to σ(p)(-) was found for phenolate and then for phenolate H-bonded complexes, followed by phenol complexes, and the lowest sensitivity was observed for phenol derivatives. The interatomic proton-acceptor distance, being a measure of the H-bond strength, was found to depend linearly on σ(p)(-) of the substituents with a positive slope for O···HB (HF or HCN) interactions and a negative slope for OH···B(-) interactions. NBO charges on the oxygen and hydrogen atoms also depend on σ(p)(-) of the substituents. In the latter case for strong H-bonded complexes (energy less than ∼-20 kcal/mol) the substituent effect works oppositely for 4-X-C(6)H(4)OH···B(-) in comparison with the 4-X-C(6)H(4)O(-)···HB systems. Moreover, following the Espinoza et al. [J. Chem. Phys. 2002, 117, 5529] and Grabowski et al. [J. Phys. Chem. B 2006, 110, 6444] classifications, the above and q(H) vs proton-acceptor distance relationships suggest a partially covalent character of the hydrogen bond for these complexes and the degree of its covalent nature depending on the substituent.

Flammability and Photo-Stability of Selected Polymer Systems

DTIC Science & Technology

1981-06-01

modifications. The 13. following methods have been used(2 8 ) : 1. Etherification or esterification of the phenolic hydroxyl groups, 2. Complex...is initiated with a view to making modifications of the flammability behaviors of phenolic resin by using substituted phenols. Also. esterification of...n-substituted phenolic resins. Modification by esterification has also been reported by Lei(29) in the synthesis of n-chloro- phenolic fiber. The

Removal of phenol from synthetic wastewater using carbon-mineral composite: Batch mechanisms and composition study

NASA Astrophysics Data System (ADS)

Kamaruddin, Mohamad Anuar; Alrozi, Rasyidah; Aziz, Hamidi Abdul; Han, Tan Yong; Yusoff, Mohd Suffian

2017-09-01

This study investigates the treatability of composite adsorbent made from waste materials and minerals which is widely available in Malaysia. The composite adsorbent was prepared based on wet attrition method which focuses on the determination of optimum dosage of each of raw materials amount by conventional design of experiment work. Zeolite, activated carbon, rice husk and limestone were ground to obtained particle size of 150 µm. 45.94% zeolite, 15.31% limestone, 4.38% activated carbon, 4.38% rice husk carbon and 30% of ordinary Portland cement (OPC). The mixture was mixed together under pre-determined mixing time. About 60% (by weight) of water was added and the mixture paste was allowed to harden for 24 hours and then submersed in water for three days for curing. Batch experimental study was performed on synthetic dissolving a known amount of solid crystal phenol with distilled water into the volumetric flasks. From the batch experimental study, it was revealed that the optimum shaking speed for removal of phenol was 200 rpm. The removal efficiency was 65%. The optimum shaking time for removing phenol was 60 minutes; the percentage achieved was 55%. The removal efficiency increased with the increased of the amount of composite adsorbent. The removal efficiency for optimum adsorbent dosage achieved 86%. Furthermore, the influence of pH solution was studied. The optimum pH for removing phenol was pH 6, with the removal percentage of 95%. The results implies that carbon-mineral based composite adsorbent is promising replacement for commercial adsorbent that provides alternative source for industrial adsorption application in various types of effluent treatment system.

Application of slightly acidic electrolyzed water for decontamination of stainless steel surfaces in animal transport vehicles.

PubMed

Ni, Li; Zheng, Weichao; Zhang, Qiang; Cao, Wei; Li, Baoming

2016-10-01

The effectiveness of slightly acidic electrolyzed water (SAEW) in reducing Escherichia coli, Salmonella typhimurim, Staphylococcus aureus or bacterial mixtures on stainless steel surfaces was evaluated and compared its efficacy with composite phenol solution for reducing total aerobic bacteria in animal transport vehicles. Stainless steel surfaces were inoculated with these strains individually or in a mixture, and sprayed with SAEW, composite phenol, or alkaline electrolyzed water for 0.5, 1, 1.5 and 2min. The bactericidal activity of SAEW increased with increasing available chlorine concentration and spraying duration. The SAEW solution of 50mgl -1 of available chlorine concentration showed significantly higher effectiveness than composite phenol in reducing the pathogens on stainless steel surfaces (P<0.05). Complete inactivation of pathogens on stainless steel surfaces were observed after treatment with alkaline electrolyzed water followed by SAEW at 50mgl -1 of available chlorine concentration for 2min or alkaline electrolyzed water treatment followed by SAEW treatment at 90mgl -1 of available chlorine concentration for 0.5min. The efficacy of SAEW in reducing total aerobic bacteria in animal transport vehicles was also determined. Vehicles in the disinfection booth were sprayed with the same SAEW, alkaline electrolyzed water and composite phenol solutions using the automatic disinfection system. Samples from vehicle surfaces were collected with sterile cotton swabs before and after each treatment. No significant differences in bactericidal efficiency were observed between SAEW and composite phenol for reducing total aerobic bacteria in the vehicles (P>0.05). SAEW was also found to be more effective when used in conjunction with alkaline electrolyzed water. Results suggest that the bactericidal efficiency of SAEW was higher than or equivalent to that of composite phenol and SAEW may be used as effective alternative for reducing microbial contamination of animal transport vehicles. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of bio-oil from induction-heating pyrolysis of food-processing sewage sludges using chromatographic analysis.

PubMed

Tsai, Wen-Tien; Lee, Mei-Kuei; Chang, Jeng-Hung; Su, Ting-Yi; Chang, Yuan-Ming

2009-05-01

In this study, gas chromatography-mass spectrometry (GC-MS) was used to analyze the pyrolytic bio-oils and gas fractions derived from the pyrolysis of industrial sewage sludges using induction-heating technique. The liquid products were obtained from the cryogenic condensation of the devolatilization fraction in a nitrogen atmosphere using a heating rate of 300 degrees C/min ranging from 25 to 500 degrees C. The analytical results showed that the pyrolysis bio-oils were very complex mixtures of organic compounds and contained a lot of nitrogenated and/or oxygenated compounds such as aliphatic hydrocarbons, phenols, pyridines, pyrroles, amines, ketones, and so on. These organic hydrocarbons containing nitrogen and/or oxygen should originate from the protein and nucleic acid textures of the microbial organisms present in the sewage sludge. The non-condensable devolatilization fractions were also composed of nitrogenated and oxygenated compounds, but contained small fractions of phenols, 1H-indoles, and fatty carboxylic acids. On the other hand, the compositions in the non-condensable gas products were principally carbon dioxide, carbon monoxide and methane analyzed by gas chromatography-thermal conductivity detector (GC-TCD).

Magnitude and nature of carbohydrate-aromatic interactions in fucose-phenol and fucose-indole complexes: CCSD(T) level interaction energy calculations.

PubMed

Tsuzuki, Seiji; Uchimaru, Tadafumi; Mikami, Masuhiro

2011-10-20

The CH/π contact structures of the fucose-phenol and fucose-indole complexes and the stabilization energies by formation of the complexes (E(form)) were studied by ab initio molecular orbital calculations. The three types of interactions (CH/π and OH/π interactions and OH/O hydrogen bonds) were compared and evaluated in a single molecular system and at the same level of theory. The E(form) calculated for the most stable CH/π contact structure of the fucose-phenol complex at the CCSD(T) level (-4.9 kcal/mol) is close to that for the most stable CH/π contact structure of the fucose-benzene complex (-4.5 kcal/mol). On the other hand the most stable CH/π contact structure of the fucose-indole complex has substantially larger E(form) (-6.5 kcal/mol). The dispersion interaction is the major source of the attraction in the CH/π contact structures of the fucose-phenol and fucose-indole complexes as in the case of the fucose-benzene complex. The electrostatic interactions in the CH/π contact structures are small (less than 1.5 kcal/mol). The nature of the interactions between the nonpolar surface of the carbohydrate and aromatic rings is completely different from that of the conventional hydrogen bonds where the electrostatic interaction is the major source of the attraction. The distributed multipole analysis and DFT-SATP analysis show that the dispersion interactions in the CH/π contact structure of fucose-indole complex are substantially larger than those in the CH/π contact structures of fucose-benzene and fucose-phenol complexes. The large dispersion interactions are responsible for the large E(form) for the fucose-indole complex.

Complex Enzyme-Assisted Extraction Releases Antioxidative Phenolic Compositions from Guava Leaves.

PubMed

Wang, Lu; Wu, Yanan; Liu, Yan; Wu, Zhenqiang

2017-09-30

Phenolics in food and fruit tree leaves exist in free, soluble-conjugate, and insoluble-bound forms. In this study, in order to enhance the bioavailability of insoluble-bound phenolics from guava leaves (GL), the ability of enzyme-assisted extraction in improving the release of insoluble-bound phenolics was investigated. Compared to untreated GL, single xylanase-assisted extraction did not change the composition and yield of soluble phenolics, whereas single cellulase or β -glucosidase-assisted extraction significantly enhanced the soluble phenolics content of PGL. However, complex enzyme-assisted extraction (CEAE) greatly improved the soluble phenolics content, flavonoids content, ABTS, DPPH, and FRAP by 103.2%, 81.6%, 104.4%, 126.5%, and 90.3%, respectively. Interestingly, after CEAE, a major proportion of phenolics existed in the soluble form, and rarely in the insoluble-bound form. Especially, the contents of quercetin and kaempferol with higher bio-activity were enhanced by 3.5- and 2.2-fold, respectively. More importantly, total soluble phenolics extracts of GL following CEAE exhibited the highest antioxidant activity and protective effect against supercoiled DNA damage. This enzyme-assisted extraction technology can be useful for extracting biochemical components from plant matrix, and has good potential for use in the food and pharmaceutical industries.

Model studies of the Cu(B) site of cytochrome c oxidase utilizing a Zn(II) complex containing an imidazole-phenol cross-linked ligand.

PubMed

Pesavento, Russell P; Pratt, Derek A; Jeffers, Jerry; van der Donk, Wilfred A

2006-07-21

Cytochrome c oxidase, the enzyme complex responsible for the four-electron reduction of O2 to H2O, contains an unusual histidine-tyrosine cross-link in its bimetallic heme a3-CuB active site. We have synthesised an unhindered, tripodal chelating ligand, BPAIP, containing the unusual ortho-imidazole-phenol linkage, which mimics the coordination environment of the CuB center. The ligand was used to investigate the physicochemical (pKa, oxidation potential) and coordination properties of the imidazole-phenol linkage when bound to a dication. Zn(II) coordination lowers the pKa of the phenol by 0.6 log units, and increases the potential of the phenolate/phenoxyl radical couple by approximately 50 mV. These results are consistent with inductive withdrawal of electron density from the phenolic ring. Spectroscopic data and theoretical calculations (DFT) were used to establish that the cationic complex [Zn(BPAIP)Br]+ has an axially distorted trigonal bipyramidal structure, with three coordinating nitrogen ligands (two pyridine and one imidazole) occupying the equatorial plane and the bromide and the tertiary amine nitrogen of the tripod in the axial positions. Interestingly, the Zn-Namine bonding interaction is weak or absent in [Zn(BPAIP)Br]+ and the complex gains stability in basic solutions, as indicated by 1H NMR spectroscopy. These observations are supported by theoretical calculations (DFT), which suggest that the electron-donating capacity of the equatorial imidazole ligand can be varied by modulation of the protonation and/or redox state of the cross-linked phenol. Deprotonation of the phenol makes the equatorial imidazole a stronger sigma-donor, resulting in an increased Zn-Nimd interaction and thereby leading to distortion of the axial ligand axis toward a more tetrahedral geometry.

Antioxidant activity evaluation of new dosage forms as vehicles for dehydrated vegetables.

PubMed

Romero-de Soto, María Dolores; García-Salas, Patricia; Fernández-Arroyo, Salvador; Segura-Carretero, Antonio; Fernández-Campos, Francisco; Clares-Naveros, Beatriz

2013-06-01

A dehydrated vegetables mixture loaded in four pharmaceutical dosage forms as powder, effervescent granulate, sugar granulate and gumdrops were investigated for their antioxidant capacity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging capacity assay, oxygen radical absorbance capacity assay and ferric reducing antioxidant potential assay. Total phenolic content of dehydrated vegetables powder mixture was also measured by the Folin-Ciocalteu method, so as to evaluate its contribution to their total antioxidant function. The effect of different temperatures on stability of these systems after 90 days storage was also evaluated. These formulations presented strong antioxidant properties and high phenolic content (279 mg gallic acid equivalent/g of sample) and thus could be potential rich sources of natural antioxidants. Antioxidant properties differed significantly among selected formulations (p < 0.05). Generally, the losses were lower in samples stored under refrigeration. To interpret the antioxidant properties a kinetic approach was performed. Degradation kinetics for the phenolic content and antioxidant capacity followed a zero-order function. Effervescent granulate was the formulation which underwent faster degradation. Contrary, sugar granulate and gumdrops were much more slowly. Time required to halve the initial amount of phenolic compounds was 589 ± 45 days for samples stored at 4 º C, and 312 ± 16 days for samples stored at room temperature. These developed dosage forms are new and innovative approach for vegetable intakes in population with special requirements providing an improvement in the administration of vegetables and fruits.

Systematic and Empirical Study of the Dependence of Polyphenol Recovery from Apricot Pomace on Temperature and Solvent Concentration Levels

PubMed Central

Cheaib, Dina; Rajha, Hiba N.; Maroun, Richard G.; Louka, Nicolas

2018-01-01

This work aims to study the impact of solvent mixture (between 0 and 50% ethanol/water mixture) and temperature (between 25°C and 75°C) levels on the solid-liquid extraction of phenolic compounds (quantity and bioactivity) from apricot pomace. Results show that the mean augmentation of 1% ethanol in the range [0–12%] enhances by three times the extraction of polyphenols compared to the same augmentation in the range [0–50%]. Similarly, the mean augmentation of 1°Celcius in the range [0–25°Celcius] enhances by two times the extraction of polyphenols compared to the same augmentation in the range [0–75°Celcius]. Moreover, 1% of ethanol exhibited a greater impact on the phenolic compound extraction than 1°Celsius. The response surface methodology showed that the optimal extraction condition was reached with 50% ethanol/water at 75°C giving a total phenolic content (TPC) of 9.8 mg GAE/g DM, a flavonoids content (FC) of 8.9 mg CE/g DM, a tannin content (TC) of 4.72 mg/L, and an antiradical activity (AA) of 44%. High-performance liquid chromatography (HPLC) analysis showed that polyphenols were influenced by the selectivity of the solvent as well as the properties of each phenolic compound. Apricot pomace extracts could therefore be used as natural bioactive molecules for many industrial applications. PMID:29618957

Soluble inhibitors/deactivators of cellulase enzymes from lignocellulosic biomass.

PubMed

Kim, Youngmi; Ximenes, Eduardo; Mosier, Nathan S; Ladisch, Michael R

2011-04-07

Liquid hot water, steam explosion, and dilute acid pretreatments of lignocellulose generate soluble inhibitors which hamper enzymatic hydrolysis as well as fermentation of sugars to ethanol. Toxic and inhibitory compounds will vary with pretreatment and include soluble sugars, furan derivatives (hydroxymethyl fulfural, furfural), organic acids (acetic, formic and, levulinic acid), and phenolic compounds. Their effect is seen when an increase in the concentration of pretreated biomass in a hydrolysis slurry results in decreased cellulose conversion, even though the ratio of enzyme to cellulose is kept constant. We used lignin-free cellulose, Solka Floc, combined with mixtures of soluble components released during pretreatment of wood, to prove that the decrease in the rate and extent of cellulose hydrolysis is due to a combination of enzyme inhibition and deactivation. The causative agents were extracted from wood pretreatment liquid using PEG surfactant, activated charcoal or ethyl acetate and then desorbed, recovered, and added back to a mixture of enzyme and cellulose. At enzyme loadings of either 1 or 25mg protein/g glucan, the most inhibitory components, later identified as phenolics, decreased the rate and extent of cellulose hydrolysis by half due to both inhibition and precipitation of the enzymes. Full enzyme activity occurred when the phenols were removed. Hence detoxification of pretreated woods through phenol removal is expected to reduce enzyme loadings, and therefore reduce enzyme costs, for a given level of cellulose conversion. Copyright © 2011 Elsevier Inc. All rights reserved.

40 CFR 401.15 - Toxic pollutants.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (technical mixture and metabolites) 14. Chlorinated benzenes (other than di-chlorobenzenes) 15. Chlorinated... ethers (chloroethyl and mixed ethers) 17. Chlorinated naphthalene 18. Chlorinated phenols (other than those listed elsewhere; includes trichlorophenols and chlorinated cresols) 19. Chloroform 20. 2...

Process for preparing fine grain silicon carbide powder

DOEpatents

Wei, G.C.

Method of producing fine-grain silicon carbide powder comprises combining methyltrimethoxysilane with a solution of phenolic resin, acetone and water or sugar and water, gelling the resulting mixture, and then drying and heating the obtained gel.

Thermal Decomposition Mechanisms of Lignin Model Compounds: From Phenol to Vanillin

NASA Astrophysics Data System (ADS)

Scheer, Adam Michael

Lignin is a complex, aromatic polymer abundant in cellulosic biomass (trees, switchgrass etc.). Thermochemical breakdown of lignin for liquid fuel production results in undesirable polycyclic aromatic hydrocarbons that lead to tar and soot byproducts. The fundamental chemistry governing these processes is not well understood. We have studied the unimolecular thermal decomposition mechanisms of aromatic lignin model compounds using a miniature SiC tubular reactor. Products are detected and characterized using time-of-flight mass spectrometry with both single photon (118.2 nm; 10.487 eV) and 1 + 1 resonance-enhanced multiphoton ionization (REMPI) as well as matrix isolation infrared spectroscopy. Gas exiting the heated reactor (300 K--1600 K) is subject to a free expansion after a residence time of approximately 100 micros. The expansion into vacuum rapidly cools the gas mixture and allows the detection of radicals and other highly reactive intermediates. By understanding the unimolecular fragmentation patterns of phenol (C6H5OH), anisole (C6H 5OCH3) and benzaldehyde (C6H5CHO), the more complicated thermocracking processes of the catechols (HO-C 6H4-OH), methoxyphenols (HO-C6H4-OCH 3) and hydroxybenzaldehydes (HO-C6H4-CHO) can be interpreted. These studies have resulted in a predictive model that allows the interpretation of vanillin, a complex phenolic ether containing methoxy, hydroxy and aldehyde functional groups. This model will serve as a guide for the pyrolyses of larger systems including lignin monomers such as coniferyl alcohol. The pyrolysis mechanisms of the dimethoxybenzenes (H3C-C 6H4-OCH3) and syringol, a hydroxydimethoxybenzene have also been studied. These results will aid in the understanding of the thermal fragmentation of sinapyl alcohol, the most complex lignin monomer. In addition to the model compound work, pyrolyisis of biomass has been studied via the pulsed laser ablation of poplar wood. With the REMPI scheme, aromatic lignin decomposition products are directly and selectively detected. A number of these products are the lignin model compounds listed above, providing a direct link between the model compound studies and the pyrolysis of actual biomass.

Optimization of pressurized liquid extraction by response surface methodology of Goji berry (Lycium barbarum L.) phenolic bioactive compounds.

PubMed

Tripodo, Giusy; Ibáñez, Elena; Cifuentes, Alejandro; Gilbert-López, Bienvenida; Fanali, Chiara

2018-01-03

Pressurized liquid extraction (PLE) has been used for the first time in this work to extract phenolic compounds from Goji berries according to a multilevel factorial design using response surface methodology. The global yield (% w/dw, weight/dry-weight), total phenolic content (TPC), total flavonoid (TF) and antioxidant activity (determined via ABTS assay, expressed as TEAC value) were used as response variables to study the effects of temperature (50-180°C) and green solvent composition (mixtures of ethanol/water). Phenolic compounds characterization was performed by high performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS). The optimum PLE conditions predicted by the model were as follows: 180°C and 86% ethanol in water with a good desirability value of 0.815. The predicted conditions were confirmed experimentally and once the experimental design was validated for commercial fruit samples, the PLE extraction of phenolic compounds from three different varieties of fruit samples (Selvatico mongolo, Bigol, and Polonia) was performed. Nine phenolic compounds were tentatively identified in these extracts, including phenolic acids and their derivatives, and flavonols. The optimized PLE conditions were compared to a conventional solid-liquid extraction, demonstrating that PLE is a useful alternative to extract phenolic compounds from Goji berry. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emergent behaviour in a chlorophenol-mineralising three-tiered microbial ‘food web’

PubMed Central

Wade, M.J.; Pattinson, R.W.; Parker, N.G.; Dolfing, J.

2016-01-01

Anaerobic digestion enables the water industry to treat wastewater as a resource for generating energy and recovering valuable by-products. The complexity of the anaerobic digestion process has motivated the development of complex models. However, this complexity makes it intractable to pin-point stability and emergent behaviour. Here, the widely used Anaerobic Digestion Model No. 1 (ADM1) has been reduced to its very backbone, a syntrophic two-tiered microbial ‘food chain’ and a slightly more complex three-tiered microbial ‘food web’, with their stability analysed as a function of the inflowing substrate concentration and dilution rate. Parameterised for phenol and chlorophenol degradation, steady-states were always stable and non-oscillatory. Low input concentrations of chlorophenol were sufficient to maintain chlorophenol- and phenol-degrading populations but resulted in poor conversion and a hydrogen flux that was too low to sustain hydrogenotrophic methanogens. The addition of hydrogen and phenol boosted the populations of all three organisms, resulting in the counterintuitive phenomena that (i) the phenol degraders were stimulated by adding hydrogen, even though hydrogen inhibits phenol degradation, and (ii) the dechlorinators indirectly benefitted from measures that stimulated their hydrogenotrophic competitors; both phenomena hint at emergent behaviour. PMID:26551153

Catalysis and co-catalysis of bond cleavages in coal and coal analogs. Final report, August 1, 1990--January 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, B.

1994-05-01

In work prior to the inception of this project, the authors observed that mixtures of phenolic materials and polyalkoxyaromatic molecules were appreciably more effective in catalyzing the decompositions of di-2-naphthyl ether and of di-1-naphthyl sulfide in tetralin solutions at 450{degrees}C than were the phenols by themselves, even though the polyalkoxyaromatic molecules, in the absence of phenolic co- catalysts, show essentially no catalytic activity. This was of appreciable interest in coal research because dinapthyl ether and dinapthyl sulfide have been employed as model compounds for coals in studies aimed at cleaving ether and sulfide bonds similar to those in coals. Themore » authors proposed (R. K. Sharma, K. P. Raman, and B. Miller) that the mixed catalysts used in these studies catalyze cleavages of ether and sulfide bonds by means of a mechanism involving electron transfer from the polyalkoxyaromatics to the substrates, which are activated as electron acceptors by hydrogen bonding to phenols. Since phenols themselves are electron donors, they also proposed that the well known effects of phenols in catalyzing the conversion of coals are due to similar electron transfer mechanisms.« less

Biodegradation of dissolved humic substances by fungi.

PubMed

Collado, Sergio; Oulego, Paula; Suárez-Iglesias, Octavio; Díaz, Mario

2018-04-01

Humic and fulvic acids constitute humic substances, a complex mixture of many different acids containing carboxyl and phenolate groups, which are not only the principal soil fertility factors but also the main pollutants present in landfill leachates or natural organic matter in water. Due to their low bacterial biodegradability, fungal biodegradation processes are key for their removal. The present study compiles and comments all the available literature on decomposition of aqueous humic substances by fungi or by their extracellular enzymes alone, focusing on the influence of the reaction conditions. The biodegradation extent mainly depends on the characteristics and concentration of the humic compounds, the type of microorganisms selected, the inoculation mode, the C and N sources, the presence of certain chemicals in the medium, the availability of oxygen, the temperature, and the pH.

Enzyme-assisted extraction enhancing the phenolic release from cauliflower (Brassica oleracea L. var. botrytis) outer leaves.

PubMed

Huynh, Nguyen Thai; Smagghe, Guy; Gonzales, Gerard Bryan; Van Camp, John; Raes, Katleen

2014-07-30

Phenolic compounds are highly present in byproducts from the cauliflower (Brassica oleracea L. var. botrytis) harvest and are thus a valuable source for valorization toward phenolic-rich extracts. In this study, we aimed to optimize and characterize the release of individual phenolic compounds from outer leaves of cauliflower, using two commercially available polysaccharide-degrading enzymes, Viscozyme L and Rapidase. As major results, the optimal conditions for the enzyme treatment were: enzyme/substrate ratio of 0.2% for Viscozyme L and 0.5% for Rapidase, temperature 35 °C, and pH 4.0. Using a UPLC-HD-TOF-MS setup, the main phenolic compounds in the extracts were identified as kaempferol glycosides and their combinations with different hydroxycinnamic acids. The most abundant components were kaempferol-3-feruloyldiglucoside and kaempferol-3-glucoside (respectively, 37.8 and 58.4 mg rutin equiv/100 g dry weight). Incubation of the cauliflower outer leaves with the enzyme mixtures resulted in a significantly higher extraction yield of kaempferol-glucosides as compared to the control treatment.

Recovering Bioactive Compounds from Olive Oil Filter Cake by Advanced Extraction Techniques

PubMed Central

Lozano-Sánchez, Jesús; Castro-Puyana, María; Mendiola, Jose A.; Segura-Carretero, Antonio; Cifuentes, Alejandro; Ibáñez, Elena

2014-01-01

The potential of by-products generated during extra-virgin olive oil (EVOO) filtration as a natural source of phenolic compounds (with demonstrated bioactivity) has been evaluated using pressurized liquid extraction (PLE) and considering mixtures of two GRAS (generally recognized as safe) solvents (ethanol and water) at temperatures ranging from 40 to 175 °C. The extracts were characterized by high-performance liquid chromatography (HPLC) coupled to diode array detection (DAD) and electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) to determine the phenolic-composition of the filter cake. The best isolation procedure to extract the phenolic fraction from the filter cake was accomplished using ethanol and water (50:50, v/v) at 120 °C. The main phenolic compounds identified in the samples were characterized as phenolic alcohols or derivatives (hydroxytyrosol and its oxidation product), secoiridoids (decarboxymethylated and hydroxylated forms of oleuropein and ligstroside aglycones), flavones (luteolin and apigenin) and elenolic acid derivatives. The PLE extraction process can be applied to produce enriched extracts with applications as bioactive food ingredients, as well as nutraceuticals. PMID:25226536

Tyrosinase-containing chitosan gels: A combined catalyst and sorbent for selective phenol removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, W.Q.; Payne, G.F.

There are a series of examples in which phenols appear as contaminants in process streams and their selective removal is required for waste minimization. For the selective removal of a phenol from a mixture, the authors are exploiting the substrate specificity of the enzyme tyrosinase to convert phenols into reactive o-quinones which are then adsorbed onto the amine-containing polymer chitosan. To effectively package the enzyme and sorbent, tyrosinase was immobilized between two chitosan gel films. The entrapment of tyrosinase between the films led to little loss of activity during immobilization, while tyrosinase leakage during incubation was limited. The chitosan gelsmore » rapidly adsorb the tyrosinase-generated product(s) of phenol oxidation while the capacity of the gels is substantially greater than the capacity of chitosan flakes. The performance of tyrosinase-containing chitosan gels significantly depends on the ratio of tyrosinase-to-chitosan. High tyrosinase-to-chitosan ratios result in less efficient use of tyrosinase, presumably due to suicide inactivation. However, the efficiency of chitosan use increases with increased tyrosinase-to-chitosan ratios.« less

Effect of Catalyst Loading on Photocatalytic Degradation of Phenol by Using N, S Co-doped TiO2

NASA Astrophysics Data System (ADS)

Yunus, N. N.; Hamzah, F.; So'aib, M. S.; Krishnan, J.

2017-06-01

The study on the effect of catalyst loading of photocatalytic degradation of phenol by using N, S co-doped TiO2 was investigated. The precursor of titania was Titanium (IV) isopropoxide (TTIP), while the sources of Nitrogen and Sulfur were ammonium nitrate and thiourea respectively. The photocatalyst were prepared by using dopant concentration at 1% of both Nitrogen and Sulphur that were prepared via sol-gel method. The photocatalyst were tested by different catalyst loading which were 1 g/L, 2g/L and 3 g/L. The gel obtained from the mixing process was dried and calcined at 600°C. The performance of the photocatalyst were tested by using phenol as a model pollutant. The mixture of photocatalyst and pollutant was left under visible light for five hours for irradiation time. The experiment showed that catalyst loading of 3 g/L able to fully degrade phenol while 1 g/L and 2 g/L of photocatalyst degraded phenol at 69.9% and 96.2% respectively.

[Chemical studies on plant polyphenols and formation of black tea polyphenols].

PubMed

Tanaka, Takashi

2008-08-01

Recent biological and pharmacological studies strongly suggested that plant polyphenols in foods, beverages and crude drugs have various health benefits. However, still there are chemically uncharacterized polyphenols, especially those with large molecular weights. The typical example is black tea polyphenols. Four tea catechins of fresh tea leaves are enzymatically oxidized in tea fermentation process of black tea manufacture to give a complex mixture of the oxidation products. Despite many efforts since 1950's, major part of the black tea polyphenols has not been clarified yet. We have investigated the oxidation mechanism of each catechin by employing a newly developed in vitro model fermentation system. The oxidation was initiated by enzymatic dehydrogenation of catechins, and subsequent intermolecular quinone-phenol coupling reactions followed by cascade-type degradation of the unstable products resulted in the formation of complex black tea polyphenols. Besides black tea polyphenols, this review introduces the chemistry of insolubilization of persimmon proanthocyanidins, wood polyphenols in connection with whisky polyphenols, and co-polymerization of cinnamaldehyde and proanthocyanidins in cinnamon bark.

The science and complexity of bitter taste.

PubMed

Drewnowski, A

2001-06-01

Food choices and eating habits are largely influenced by how foods taste. Without being the dominant taste sensation, bitter taste contributes to the complexity and enjoyment of beverages and foods. Compounds that are perceived as bitter do not share a similar chemical structure. In addition to peptides and salts, bitter compounds in foods may include plant-derived phenols and polyphenols, flavonoids, catechins, and caffeine. Recent studies have shown that humans possess a multitude of bitter taste receptors and that the transduction of bitter taste may differ between one compound and another. Studies of mixture interactions suggest further that bitter compounds suppress or enhance sweet and sour tastes and interact with volatile flavor molecules. Caffeine, a natural ingredient of tea, coffee, and chocolate, has a unique flavor profile. Used as a flavoring agent, it enhances the sensory appeal of beverages. Research developments on the genetics and perception of bitter taste add to our understanding of the role of bitterness in relation to food preference.

Thermal/Pyrolysis Gas Flow Analysis of Carbon Phenolic Material

NASA Technical Reports Server (NTRS)

Clayton, J. Louie

2001-01-01

Provided in this study are predicted in-depth temperature and pyrolysis gas pressure distributions for carbon phenolic materials that are externally heated with a laser source. Governing equations, numerical techniques and comparisons to measured temperature data are also presented. Surface thermochemical conditions were determined using the Aerotherm Chemical Equilibrium (ACE) program. Surface heating simulation used facility calibrated radiative and convective flux levels. Temperatures and pyrolysis gas pressures are predicted using an upgraded form of the SINDA/CMA program that was developed by NASA during the Solid Propulsion Integrity Program (SPIP). Multispecie mass balance, tracking of condensable vapors, high heat rate kinetics, real gas compressibility and reduced mixture viscosity's have been added to the algorithm. In general, surface and in-depth temperature comparisons are very good. Specie partial pressures calculations show that a saturated water-vapor mixture is the main contributor to peak in-depth total pressure. Further, for most of the cases studied, the water-vapor mixture is driven near the critical point and is believed to significantly increase the local heat capacity of the composite material. This phenomenon if not accounted for in analysis models may lead to an over prediction in temperature response in charring regions of the material.

Ferulic acid enhances IgE binding to peanut allergens in western blots.

USDA-ARS?s Scientific Manuscript database

Phenolic compounds at high concentrations are known to form insoluble complexes with proteins. We hypothesized that this complex formation could interfere with Western blot and ELISA assays for peanut allergens. To verify this, three simple phenolic compounds (ferulic, caffeic, and chlorogenic acids...

Sprayable lightweight ablative coating

NASA Technical Reports Server (NTRS)

Simpson, William G. (Inventor); Sharpe, Max H. (Inventor); Hill, William E. (Inventor)

1991-01-01

An improved lightweight, ablative coating is disclosed that may be spray applied and cured without the development of appreciable shrinkage cracks. The ablative mixture consists essentially of phenolic microballoons, hollow glass spheres, glass fibers, ground cork, a flexibilized resin binder, and an activated colloidal clay.

Anti-Escherichia coli activity of extracts from Schinus terebinthifolius fruits and leaves.

PubMed

da Silva, Jessica H S; Simas, Naomi K; Alviano, Celuta S; Alviano, Daniela S; Ventura, José A; de Lima, Eliandro J; Seabra, Sergio H; Kuster, Ricardo M

2018-06-01

Ethanol extracts obtained from Schinus terebinthifolius Raddi fruits and leaves were active against Escherichia coli with MIC of 78 μg mL -1 for both extracts. Phytochemical analyses revealed a major presence of phenolic acids, tannins, fatty acids and acid triterpenes in the leaves and phenolic acids, fatty acids, acid triterpenes and biflavonoids in the fruits. Major compounds isolated from the plant, such as the acid triterpene schinol, the phenolic acid derivative ethyl gallate and the biflavonoids agathisflavone and tetrahydroamentoflavone, showed very little activity against E. coli. Bioautography of the ethanol extracts on silica gel plate showed inhibition zones for E. coli. They were removed from the plate and the compounds identified as a mixture of myristic, pentadecanoic, palmitic, heptadecanoic, stearic, nonadecanoic, eicosanoic, heneicosanoic and behenic fatty acids.

Isolation of tert-alkylphenols from the products of alkylation of phenols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesterova, T.N.; Verevkin, S.P.; Rempel', R.D.

1987-08-10

The authors studied the conditions of isolation of tert-amyl-, hexyl-, heptyl-, octyl-, decyl-, and dodecylphenols, and tert-alkylcresols, alkylpyrocatechols, and alkylhydroquinones from alkylation products. The compounds were isolated in all cases from reaction mixtures obtained in presence of cation-exchange resins of the KU-2 type. A preliminary stage, flash evaporation of the reaction mass at 4-13 Pa for 5-15 min, is needed to prevent decomposition of tert-alkylphenols during their isolation from acid reaction mixtures by fractionation. Flash distillation of high-boiling tert-alkylphenols should be conducted in presence of a component lowering the boiling point of the mixture, added in 1:(0.5-1.0) weight ratio ofmore » original mixture to the component.« less

[Effect of soil phenolic acids on soil microbe of coal-mining depressed land after afforestation restoration by different tree species].

PubMed

Ji, Li; Yang, Li Xue

2017-12-01

Phenolic acids are one of the most important factors that influence microbial community structure. Investigating the dynamic changes of phenolic acids and their relationship with the microbial community structure in plantation soils with different tree species could contribute to better understanding and revealing the mechanisms of microbial community changes under afforestation restoration in coal-mining subsidence areas. In this study, plantations of three conifer and one deciduous species (Pinus koraiensis, Larix gmelinii, Pinus sylvestris var. mongolica, and Populus ussuriensis) were established on abandoned coal-mining subsidence areas in Baoshan District, Shuangyashan City. The contents of soil phenols, 11 types of phenolic acids, and microbial communities in all plots were determined. The results showed that the contents of soil complex phenol in plantations were significantly higher than that of abandoned land overall. Specifically, soils in larch and poplar plantations had higher contents of complex phenol, while soils in larch and Korean pine plantations had greater contents of total phenol. Moreover, soil in the P. koraiensis plantation had a higher content of water-soluble phenol compared with abandoned lands. The determination of 11 phenolic acids indicated that the contents of ferulic acid, abietic acid, β-sitosterol, oleanolic acid, shikimic acid, linoleic acid, and stearic acid were higher in plantation soils. Although soil phenol contents were not related with soil microbial biomass, the individual phenolic acids showed a significant relationship with soil microbes. Ferulic acid, abietic acid, and β-sitosterol showed significant promoting effects on soil microbial biomass, and they showed positive correlations with fungi and fungi/bacteria ratio. These three phenolic acids had higher contents in the poplar plantation, suggesting that poplar affo-restation had a beneficial effect on soil quality in coal-mining subsidence areas.

Phenolic compounds containing/neutral fractions extract and products derived therefrom from fractionated fast-pyrolysis oils

DOEpatents

Chum, Helena L.; Black, Stuart K.; Diebold, James P.; Kreibich, Roland E.

1993-01-01

A process for preparing phenol-formaldehyde novolak resins and molding compositions in which portions of the phenol normally contained in said resins are replaced by a phenol/neutral fractions extract obtained from fractionating fast-pyrolysis oils. The fractionation consists of a neutralization stage which can be carried out with aqueous solutions of bases or appropriate bases in the dry state, followed by solvent extraction with an organic solvent having at least a moderate solubility parameter and good hydrogen bonding capacity. Phenolic compounds-containing/neutral fractions extracts obtained by fractionating fast-pyrolysis oils from a lignocellulosic material, is such that the oil is initially in the pH range of 2-4, being neutralized with an aqueous bicarbonate base, and extracted into a solvent having a solubility parameter of approximately 8.4-9.11 [cal/cm.sup.3 ].sup.1/2 with polar components in the 1.8-3.0 range and hydrogen bonding components in the 2-4.8 range and the recovery of the product extract from the solvent with no further purification being needed for use in adhesives and molding compounds. The product extract is characterized as being a mixture of very different compounds having a wide variety of chemical functionalities, including phenolic, carbonyl, aldehyde, methoxyl, vinyl and hydroxyl. The use of the product extract on phenol-formaldehyde thermosetting resins is shown to have advantages over the conventional phenol-formaldehyde resins.

CAPILLARY ELECTROPHORESIS IN THE ANALYSIS OF HUMIC SUBSTANCES FACTS AND ARTIFACTS

EPA Science Inventory

Humic substances, extracted as mixtures from soil and surface waters according to their solubility in acids and bases, are relatively high-molecular-mass polyelectrolytes containing aromatic, aliphatic and heterocyclic subunits. The degree of ionization of their phenolic and carb...

Fiber reinforced hybrid phenolic foam

NASA Astrophysics Data System (ADS)

Desai, Amit

Hybrid composites in recent times have been developed by using more than one type of fiber reinforcement to bestow synergistic properties of the chosen filler and matrix and also facilitating the design of materials with specific properties matched to end use. However, the studies for hybrid foams have been very limited because of problems related to fiber dispersion in matrix, non uniform mixing due to presence of more than one filler and partially cured foams. An effective approach to synthesize hybrid phenolic foam has been proposed and investigated here. Hybrid composite phenolic foams were reinforced with chopped glass and aramid fibers in varied proportions. On assessing mechanical properties in compression and shear several interesting facts surfaced but overall hybrid phenolic foams exhibited a more graceful failure, greater resistance to cracking and were significantly stiffer and stronger than foams with only glass and aramid fibers. The optimum fiber ratio for the reinforced hybrid phenolic foam system was found to be 1:1 ratio of glass to aramid fibers. Also, the properties of hybrid foam were found to deviate from rule of mixture (ROM) and thus the existing theories of fiber reinforcement fell short in explaining their complex behavior. In an attempt to describe and predict mechanical behavior of hybrid foams a statistical design tool using analysis of variance technique was employed. The utilization of a statistical model for predicting foam properties was found to be an appropriate tool that affords a global perspective of the influence of process variables such as fiber weight fraction, fiber length etc. on foam properties (elastic modulus and strength). Similar approach could be extended to study other fiber composite foam systems such as polyurethane, epoxy etc. and doing so will reduce the number of experimental iterations needed to optimize foam properties and identify critical process variables. Diffusivity, accelerated aging and flammability of hybrid foams were evaluated and the results indicate that hybrid foam surpassed several commercial foams and thus could fulfill the current needs for an insulation material which is low cost, has excellent fire properties and retains compressive stiffness even after aging.

Relationship in between Chemical Oxidation and Browning of Flavanols

NASA Astrophysics Data System (ADS)

Dong, X.; Zhang, Y. L.; Wang, F.; Pang, M. X.; Qi, J. H.

2016-08-01

Catechin, epicatechin and chlorogenic acid are widely distributed in the plant kingdom. At present, influencing factors of phenol chemical oxidation is little research. In order to study non-enzymatic browning factors, this research utilized catechin, epicatechin and chlorogenic acid to establish simulation systems. The browning degree and products of flavanols were investigated by transmittance and high-performance liquid chromatography (HPLC). The main results and conclusions were follows. The brown generation is increased after phenols of chemical oxidation at 50°C and at pH 3.7 phosphate buffered saline, the sequence of influencing factor of browning is pH > kind of phenol > temperature. Oxidation of compounds of catechin and epicatechin results in formation of their Methylene quinone or o -Quinones. In addition, oxidation products of catechin, epicatechin and chlorogenic acid were mixture of different molecular sizes. The research has showed that brown generation correlated well with chemical oxidation of phenols and chemical oxidation reaction generated larger molecular weight polymers.

Bioremediation of steel plant wastewater and enhanced electricity generation in microbial desalination cell.

PubMed

Shinde, Omkar A; Bansal, Ankita; Banerjee, Angela; Sarkar, Supriya

2018-05-01

Microbial desalination cell (MDC) is a propitious technology towards water desalination by utilizing wastewater as an energy source. In this study, a multi-chambered MDC was used to bioremediate steel plant wastewater using the same wastewater as a fuel for anodic bacteria. A pure culture of Pseudomonas putida MTCC 1194 was isolated and inoculated to remove toxic phenol. Three different inoculum conditions, namely P. putida (INC-A), a mixture of P. putida and activated sludge (INC-B), and activated sludge alone (INC-C) were employed in an anodic chamber to mainly compare the electricity generation and phenol degradation in MDCs. The study revealed the maximum phenol removal of 82 ± 2.4%, total dissolved solids (TDS) removal of 68 ± 1.5%, and power generation of 10.2 mW/m 2 using INC-B. The synergistic interactions between microorganisms, can enhance the toxic phenol degradation and also electricity generation in MDC for onsite wastewater application.

A 1H NMR Investigation of the Interaction between Phenolic Acids Found in Mango (Manguifera indica cv Ataulfo) and Papaya (Carica papaya cv Maradol) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) Free Radicals

PubMed Central

López-Martínez, Luis M.; Santacruz-Ortega, Hisila; Navarro, Rosa-Elena; Sotelo-Mundo, Rogerio R.; González-Aguilar, Gustavo A.

2015-01-01

The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this paper, we used 1H NMR to analyze the interactions and mechanisms that are present in major phenolic acids found in mango (gallic, protocatechuic, chlorogenic and vanillic acids) and papaya (caffeic, ferulic and p-coumaric acids), and the DPPH radical was used to evaluate the effect of the antioxidant mixtures. The interactions were found to occur via hydrogen bonds between the -OH and -COOH groups. Moreover, the phenolic acids exhibit two types of mechanisms for the neutralization of the DPPH radical. According to the results, these two mechanisms are Hydrogen Atom Transfer (HAT) and Single Electron Transfer (SET). The ability of the phenolic acid to neutralize the DPPH radical decreases in the following order in mango: gallic > chlorogenic > protocatechuic > vanillic. Moreover, within the acids found in papaya, the order was as follows: caffeic > p-coumaric > ferulic. PMID:26559189

A ¹H NMR Investigation of the Interaction between Phenolic Acids Found in Mango (Manguifera indica cv Ataulfo) and Papaya (Carica papaya cv Maradol) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) Free Radicals.

PubMed

López-Martínez, Luis M; Santacruz-Ortega, Hisila; Navarro, Rosa-Elena; Sotelo-Mundo, Rogerio R; González-Aguilar, Gustavo A

2015-01-01

The benefits of phenolic acids on human health are very often ascribed to their potential to counteract free radicals to provide antioxidant protection. This potential has been attributed to their acidic chemical structure, which possesses hydroxyl groups in different positions. Phenolic acids can interact between themselves and exhibit an additive, antagonistic or synergistic effect. In this paper, we used 1H NMR to analyze the interactions and mechanisms that are present in major phenolic acids found in mango (gallic, protocatechuic, chlorogenic and vanillic acids) and papaya (caffeic, ferulic and p-coumaric acids), and the DPPH radical was used to evaluate the effect of the antioxidant mixtures. The interactions were found to occur via hydrogen bonds between the -OH and -COOH groups. Moreover, the phenolic acids exhibit two types of mechanisms for the neutralization of the DPPH radical. According to the results, these two mechanisms are Hydrogen Atom Transfer (HAT) and Single Electron Transfer (SET). The ability of the phenolic acid to neutralize the DPPH radical decreases in the following order in mango: gallic > chlorogenic > protocatechuic > vanillic. Moreover, within the acids found in papaya, the order was as follows: caffeic > p-coumaric > ferulic.

Ferulic acid enhances IgE binding to peanut allergens in western blots.

USDA-ARS?s Scientific Manuscript database

Because phenolic compounds can precipitate or complex with proteins, we postulated that interactions of phenolics with IgE antibodies help enhance IgE binding to peanut allergens in Western blots. Three different phenolics, such as, ferulic, caffeic and chlorogenic acids were examined. Each was mixe...

Hydrogen Bond Lifetimes and Energetics for Solute-Solvent Complexes Studied with 2D-IR Vibrational Echo Spectroscopy

PubMed Central

Zheng, Junrong; Fayer, Michael D.

2008-01-01

Weak π hydrogen bonded solute-solvent complexes are studied with ultrafast two dimensional infrared (2D-IR) vibrational echo chemical exchange spectroscopy, temperature dependent IR absorption spectroscopy, and density functional theory calculations. Eight solute-solvent complexes composed of a number of phenol derivatives and various benzene derivatives are investigated. The complexes are formed between the phenol derivative (solute) in a mixed solvent of the benzene derivative and CCl4. The time dependence of the 2D-IR vibrational echo spectra of the phenol hydroxyl stretch is used to directly determine the dissociation and formation rates of the hydrogen bonded complexes. The dissociation rates of the weak hydrogen bonds are found to be strongly correlated with their formation enthalpies. The correlation can be described with an equation similar to the Arrhenius equation. The results are discussed in terms of transition state theory. PMID:17373792

Rapid profiling of polymeric phenolic acids in Salvia miltiorrhiza by hybrid data-dependent/targeted multistage mass spectrometry acquisition based on expected compounds prediction and fragment ion searching.

PubMed

Shen, Yao; Feng, Zijin; Yang, Min; Zhou, Zhe; Han, Sumei; Hou, Jinjun; Li, Zhenwei; Wu, Wanying; Guo, De-An

2018-04-01

Phenolic acids are the major water-soluble components in Salvia miltiorrhiza (>5%). According to previous studies, many of them contribute to the cardiovascular effects and antioxidant effects of S. miltiorrhiza. Polymeric phenolic acids can be considered as the tanshinol derived metabolites, e.g., dimmers, trimers, and tetramers. A strategy combined with tanshinol-based expected compounds prediction, total ion chromatogram filtering, fragment ion searching, and parent list-based multistage mass spectrometry acquisition by linear trap quadropole-orbitrap Velos mass spectrometry was proposed to rapid profile polymeric phenolic acids in S. miltiorrhiza. More than 480 potential polymeric phenolic acids could be screened out by this strategy. Based on the fragment information obtained by parent list-activated data dependent multistage mass spectrometry acquisition, 190 polymeric phenolic acids were characterized by comparing their mass information with literature data, and 18 of them were firstly detected from S. miltiorrhiza. Seven potential compounds were tentatively characterized as new polymeric phenolic acids from S. miltiorrhiza. This strategy facilitates identification of polymeric phenolic acids in complex matrix with both selectivity and sensitivity, which could be expanded for rapid discovery and identification of compounds from complex matrix. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of antioxidant activity in Victorian marine algal extracts using high performance thin-layer chromatography and multivariate analysis.

PubMed

Agatonovic-Kustrin, Snezana; Morton, David W; Ristivojević, Petar

2016-10-14

The aim of this study was to develop and validate a rapid and simple high performance thin layer chromatographic (HPTLC) method to screen for antioxidant activity in algal samples. 16 algal species were collected from local Victorian beaches. Fucoxanthin, one of the most abundant marine carotenoids was quantified directly from the HPTLC plates before derivatization, while derivatization either with 2,2-diphenyl-1-picrylhydrazyl (DPPH) or ferric chloride (FeCl 3 ) was used to analyze antioxidants in marine algae, based on their ability to scavenge non biological stable free radical (DPPH) or to chelate iron ions. Principal component analysis of obtained HPTLC fingerprints has classified algae species into 5 groups according to their chemical/antioxidant profiles. The investigated brown algae samples were found to be rich in non-and moderate-polar compounds and phenolic compounds with antioxidant activity. Most of the phenolic iron chelators also have shown free radical scavenging activity. Strong positive and significant correlations between total phenolic content and DPPH radical scavenging activity showed that, phenolic compounds, including flavonoids are the main contributors of antioxidant activity in these species. The results suggest that certain brown algae possess significantly higher antioxidant potential when compared to red or green algae and could be considered for future applications in medicine, dietary supplements, cosmetics or food industries. Cystophora monilifera extract was found to have the highest antioxidant concentration, followed by Zonaria angustata, Cystophora pectinate, Codium fragile, and Cystophora pectinata. Fucoxanthin was found mainly in the brown algae species. The proposed methods provide an edge in terms of screening for antioxidants and quantification of antioxidant constituents in complex mixtures. The current application also demonstrates flexibility and versatility of a standard HPTLC system in the drug discovery. Proposed methods could be used for the bioassay-guided isolation of unknown natural antioxidants and subsequent identification if combined with spectroscopic identification. Copyright © 2016 Elsevier B.V. All rights reserved.

Inhibition of tyrosine phenol-lyase by tyrosine homologues.

PubMed

Do, Quang; Nguyen, Giang T; Phillips, Robert S

2016-09-01

We have designed, synthesized, and evaluated tyrosine homologues and their O-methyl derivatives as potential inhibitors for tyrosine phenol lyase (TPL, E.C. 4.1.99.2). Recently, we reported that homologues of tryptophan are potent inhibitors of tryptophan indole-lyase (tryptophanase, TIL, E.C. 4.1.99.1), with K i values in the low µM range (Do et al. Arch Biochem Biophys 560:20-26, 2014). As the structure and mechanism for TPL is very similar to that of TIL, we postulated that tyrosine homologues could also be potent inhibitors of TPL. However, we have found that homotyrosine, bishomotyrosine, and their corresponding O-methyl derivatives are competitive inhibitors of TPL, which exhibit K i values in the range of 0.8-1.5 mM. Thus, these compounds are not potent inhibitors, but instead bind with affinities similar to common amino acids, such as phenylalanine or methionine. Pre-steady-state kinetic data were very similar for all compounds tested and demonstrated the formation of an equilibrating mixture of aldimine and quinonoid intermediates upon binding. Interestingly, we also observed a blue-shift for the absorbance peak of external aldimine complexes of all tyrosine homologues, suggesting possible strain at the active site due to accommodating the elongated side chains.

Sequence-Selective Formation of Synthetic H-Bonded Duplexes

PubMed Central

2017-01-01

Oligomers equipped with a sequence of phenol and pyridine N-oxide groups form duplexes via H-bonding interactions between these recognition units. Reductive amination chemistry was used to synthesize all possible 3-mer sequences: AAA, AAD, ADA, DAA, ADD, DAD, DDA, and DDD. Pairwise interactions between the oligomers were investigated using NMR titration and dilution experiments in toluene. The measured association constants vary by 3 orders of magnitude (102 to 105 M–1). Antiparallel sequence-complementary oligomers generally form more stable complexes than mismatched duplexes. Mismatched duplexes that have an excess of H-bond donors are stabilized by the interaction of two phenol donors with one pyridine N-oxide acceptor. Oligomers that have a H-bond donor and acceptor on the ends of the chain can fold to form intramolecular H-bonds in the free state. The 1,3-folding equilibrium competes with duplex formation and lowers the stability of duplexes involving these sequences. As a result, some of the mismatch duplexes are more stable than some of the sequence-complementary duplexes. However, the most stable mismatch duplexes contain DDD and compete with the most stable sequence-complementary duplex, AAA·DDD, so in mixtures that contain all eight sequences, sequence-complementary duplexes dominate. Even higher fidelity sequence selectivity can be achieved if alternating donor–acceptor sequences are avoided. PMID:28857551

Validation of a DNA IQ-based extraction method for TECAN robotic liquid handling workstations for processing casework.

PubMed

Frégeau, Chantal J; Lett, C Marc; Fourney, Ron M

2010-10-01

A semi-automated DNA extraction process for casework samples based on the Promega DNA IQ™ system was optimized and validated on TECAN Genesis 150/8 and Freedom EVO robotic liquid handling stations configured with fixed tips and a TECAN TE-Shake™ unit. The use of an orbital shaker during the extraction process promoted efficiency with respect to DNA capture, magnetic bead/DNA complex washes and DNA elution. Validation studies determined the reliability and limitations of this shaker-based process. Reproducibility with regards to DNA yields for the tested robotic workstations proved to be excellent and not significantly different than that offered by the manual phenol/chloroform extraction. DNA extraction of animal:human blood mixtures contaminated with soil demonstrated that a human profile was detectable even in the presence of abundant animal blood. For exhibits containing small amounts of biological material, concordance studies confirmed that DNA yields for this shaker-based extraction process are equivalent or greater to those observed with phenol/chloroform extraction as well as our original validated automated magnetic bead percolation-based extraction process. Our data further supports the increasing use of robotics for the processing of casework samples. Crown Copyright © 2009. Published by Elsevier Ireland Ltd. All rights reserved.

Aerogel and xerogel composites for use as carbon anodes

DOEpatents

Cooper, John F.; Tillotson, Thomas M.; Hrubesh, Lawrence W.

2010-10-12

A method for forming a reinforced rigid anode monolith and fuel and product of such method. The method includes providing a solution of organic aerogel or xerogel precursors including at least one of a phenolic resin, phenol (hydroxybenzene), resorcinol(1,3-dihydroxybenzene), or catechol(1,2-dihydroxybenzene); at least one aldehyde compound selected from the group consisting of formaldehyde, acetaldehyde, and furfuraldehyde; and an alkali carbonate or phosphoric acid catalyst; adding internal reinforcement materials comprising carbon to said precursor solution to form a precursor mixture; gelling said precursor mixture to form a composite gel; drying said composite gel; and pyrolyzing said composite gel to form a wettable aerogel/carbon composite or a wettable xerogel/carbon composite, wherein said composites comprise chars and said internal reinforcement materials, and wherein said composite is suitable for use as an anode with the chars being fuel capable of being combusted in a molten salt electrochemical fuel cell in the range from 500 C to 800 C to produce electrical energy. Additional methods and systems/compositions are also provided.

Recycling of phenol from aqueous solutions by pervaporation with ZSM-5/PDMS/PVDF hollow fiber composite membrane

NASA Astrophysics Data System (ADS)

Li, Dan; Yao, Jie; Sun, Hao; Liu, Bing; van Agtmaal, Sjack; Feng, Chunhui

2018-01-01

Zeolite (ZSM-5)/polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) hollow fiber composite membrane was prepared by dynamic negative pressure. The influence of ZSM-5 silanization, coating time and concentration of ZSM-5 on the resulting pervaporation (PV) performance of composite membranes was investigated. The contact angle (CA) was used to measure surface hydrophobic property and it was found that the water contact angle of the membrane was increased significantly from 99° to 132° when the concentration of ZSM-5 increased from 0% to 50%. The morphology of the membrane was characterized by scanning electron microscope (SEM) and those SEM images illustrated that the thickness of the separating layer has obvious differences at varying coating times. Furthermore, the membranes were investigated in PV process to recycle phenol from aqueous solutions as feed mixtures. The impact of phenol concentration in feed, temperature and pressure of penetration side on the PV performance of membrane was studied systematically. When the ZSM-5 concentration was 40% and the coating time was 60 min, separation factor and phenol permeability were 4.56 and 5.78 g/(m2 h), respectively. ZSM-5/PDMS/PVDF membrane significantly improved the recovery efficiency of phenols.

Growth of Azotobacter chroococcum in chemically defined media containing p-hydroxybenzoic acid and protocatechuic acid.

PubMed

Juarez, B; Martinez-Toledo, M V; Gonzalez-Lopez, J

2005-06-01

Growth and utilization of different phenolic acids present in olive mill wastewater (OMW) by Azotobacter chroococcum were studied in chemically defined media. Growth and utilization of phenolic acids were only detected when the microorganism was cultured on p-hydroxybenzoic acid at concentration from 0.01% to 0.5% (w/v) and protocatechuic acid at concentration from 0.01% to 0.3% (w/v) as sole carbon sources suggesting that only these phenolic compounds could be utilized as a carbon source by A. chroococcum. Moreover when culture media were added with a mixture of 0.3% of protocatechuic acid and 0.3% p-hydroxybenzoic acid, the microorganism degradated in first place protocatechuic acid and once the culture medium was depleted of this compound, the degradation of p-hydroxybenzoic acid commenced very fast.

Influence of alternative electron acceptors on the anaerobic biodegradability of chlorinated phenols and benzoic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haeggblom, M.M.; Rivera, M.D.; Young, L.Y.

1993-04-01

Methanogeneic conditions can promote the biodegradation of a number of halogenated aromatic compounds. This study, using sediments from freshwater and estuarine sites, is an evaluation of the anaerobic biodegradability of monochlorinated phenols and benzoic acids coupled to denitrification, sulfidogenesis, and methanogenesis. The results indicate that chlorinated phenols and benzoic acids are biodegradable under at least one set of anaerobic conditions. Metabolism depends both on the electron acceptor available and on the position of the chlorine substituent. Presence of alternative electron acceptors, nitrate, sulfate, and carbonate, can affect degradation rates and substrate specificities. Since contaminated sites usually have mixtures of wastes,more » bioremediation efforts may need to consider the activities of diverse anaerobic communities to carry out effective treatment of all components. 37 refs., 4 figs., 4 tabs.« less

Synergistic Hepatoprotective and Antioxidant Effect of Artichoke, Fig, Blackberry Herbal Mixture on HepG2 Cells and Their Metabolic Profiling Using NMR Coupled with Chemometrics.

PubMed

Youssef, Fadia S; Labib, Rola M; Eldahshan, Omayma A; Singab, Abdel Nasser B

2017-12-01

The edible plants have long been reported to possess a lot of biological activities. Herein, the hepatoprotective and the antioxidant activities of the aqueous infusion of the edible parts of Cynara cardunculus, Ficus carica, and Morus nigra and their herbal mixture (CFM) was investigated in vitro using CCl 4 induced damage in HepG2 cells. The highest amelioration was observed via the consumption of CFM at 1 mg/ml showing 47.00% and 37.09% decline in aspartate transaminase and alanine transaminase and 77.32% and 101.02% increase in reduced glutathione and superoxide dismutase comparable to CCl 4 treated cells. Metabolic profiling of their aqueous infusions was done using nuclear magnetic resonance spectroscopic experiments coupled with chemometrics particularly hierarchical cluster analysis (HCA) and principal component analysis (PCA). The structural closeness of the various metabolites existing in black berry and the mixture as reflected in the PCA score plot and HCA processed from the 1 H-NMR spectral data could eventually explained the close values in their biological behavior. For fig and artichoke, the existence of different phenolic metabolites that act synergistically could greatly interpret their potent biological behavior. Thus, it can be concluded that a herbal mixture composed of black berry, artichoke, and fig could afford an excellent natural candidate to combat oxidative stress and counteract hepatic toxins owing to its phenolic compounds. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Optimization of the mineralization of a mixture of phenolic pollutants under a ferrioxalate-induced solar photo-Fenton process.

PubMed

Monteagudo, J M; Durán, A; Aguirre, M; San Martín, I

2011-01-15

The mineralization of solutions containing a mixture of three phenolic compounds, gallic, p-coumaric and protocatechuic acids, in a ferrioxalate-induced solar photo-Fenton process was investigated. The reactions were carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and neuronal networks that included the following variables: pH, temperature, solar power, air flow and initial concentrations of H(2)O(2), Fe(II) and oxalic acid. Under optimal conditions, total elimination of the original compounds and 94% TOC removal of the mixture were achieved in 5 and 194 min, respectively. pH and initial concentrations of H(2)O(2) and Fe(II) were the most significant factors affecting the mixture mineralization. The molar correlation between consumed hydrogen peroxide and removed TOC was always between 1 and 3. A detailed analysis of the reaction was presented. The values of the pseudo-first-order mineralization kinetic rate constant, k(TOC), increased as initial Fe(II) and H(2)O(2) concentrations and temperature increased. The optimum pH value also slightly increased with greater Fe(II) and hydrogen peroxide concentrations but decreased when temperature increased. OH and O(2)(-) radicals were the main oxidative intermediate species in the process, although singlet oxygen ((1)O(2)) also played a role in the mineralization reaction. Copyright © 2010 Elsevier B.V. All rights reserved.

Molecular complexes of alprazolam with carboxylic acids, boric acid, boronic acids, and phenols. Evaluation of supramolecular heterosynthons mediated by a triazole ring.

PubMed

Varughese, Sunil; Azim, Yasser; Desiraju, Gautam R

2010-09-01

A series of molecular complexes, both co-crystals and salts, of a triazole drug-alprazolam-with carboxylic acids, boric acid, boronic acids, and phenols have been analyzed with respect to heterosynthons present in the crystal structures. In all cases, the triazole ring behaves as an efficient hydrogen bond acceptor with the acidic coformers. The hydrogen bond patterns exhibited with aromatic carboxylic acids were found to depend on the nature and position of the substituents. Being a strong acid, 2,6-dihydroxybenzoic acid forms a salt with alprazolam. With aliphatic dicarboxylic acids alprazolam forms hydrates and the water molecules play a central role in synthon formation and crystal packing. The triazole ring makes two distinct heterosynthons in the molecular complex with boric acid. Boronic acids and phenols form consistent hydrogen bond patterns, and these are seemingly independent of the substitutional effects. Boronic acids form noncentrosymmetric cyclic synthons, while phenols form O--H...N hydrogen bonds with the triazole ring.

Varying electronegativity of OH/O- groups depending on the nature and strength of H-bonding in phenol/phenolate involved in H-bond complexation.

PubMed

Krygowski, Tadeusz M; Szatyłowicz, Halina

2006-06-08

Application of the Domenicano et al. method of estimating group electronegativity from angular geometry of the ring in monosubstituted benzene derivatives allowed us to find how the electronegativity of OH/O(-) groups in H-bonded complexes of phenol and phenolate depends on the nature and strength of H-bond. For complexes in which the OH group is only proton donating in the H-bond, a linear dependence of the estimated electronegativity on O...O(N) interatomic distance was found for experimental (CSD base retrieved) data. The following rule is observed: the weaker the H-bond is, the more electronegative the OH group is. If apart from this kind of interaction the oxygen is proton accepting, then an increase of electronegativity is observed. Modeling (B3LYP/6-311+G) the variation of the strength of the H-bond by the fluoride anion approaching the OH leads to qualitatively the same picture as the scatter plots for experimental data.

Phenolic acid sorption to biochars from mixtures of feedstock materials

USDA-ARS?s Scientific Manuscript database

In an effort to customize biochars for soil amendments, multiple feedstocks have been combined in various ratios prior to pyrolysis. The resulting variation in the chemistry and structure can affect a biochar’s adsorption capacity, which influences the bioavailability of many chemical compounds in t...

ProPhenol-Catalyzed Asymmetric Additions by Spontaneously Assembled Dinuclear Main Group Metal Complexes

PubMed Central

2016-01-01

Conspectus The development of catalytic enantioselective transformations has been the focus of many research groups over the past half century and is of paramount importance to the pharmaceutical and agrochemical industries. Since the award of the Nobel Prize in 2001, the field of enantioselective transition metal catalysis has soared to new heights, with the development of more efficient catalysts and new catalytic transformations at increasing frequency. Furthermore, catalytic reactions that allow higher levels of redox- and step-economy are being developed. Thus, alternatives to asymmetric alkene dihydroxylation and the enantioselective reduction of α,β-unsaturated ketones can invoke more strategic C–C bond forming reactions, such as asymmetric aldol reactions of an aldehyde with α-hydroxyketone donors or enantioselective alkynylation of an aldehyde, respectively. To facilitate catalytic enantioselective addition reactions, including the aforementioned aldol and alkynylation reactions, our lab has developed the ProPhenol ligand. In this Account, we describe the development and application of the ProPhenol ligand for asymmetric additions of both carbon- and heteroatom-based nucleophiles to various electrophiles. The ProPhenol ligand spontaneously forms chiral dinuclear metal complexes when treated with an alkyl metal reagent, such as Et2Zn or Bu2Mg. The resulting complex contains both a Lewis acidic site to activate an electrophile and a Brønsted basic site to deprotonate a pronucleophile. Initially, our research focused on the use of Zn-ProPhenol complexes to facilitate the direct aldol reaction. Fine tuning of the reaction through ligand modification and the use of additives enabled the direct aldol reaction to proceed in high yields and stereoselectivities with a broad range of donor substrates, including acetophenones, methyl ynones, methyl vinyl ketone, acetone, α-hydroxy carbonyl compounds, and glycine Schiff bases. Additionally, an analogous magnesium ProPhenol complex was used to facilitate enantioselective diazoacetate aldol reactions with aryl, α,β-unsaturated, and aliphatic aldehydes. The utility of bimetallic ProPhenol catalysts was extended to asymmetric additions with a wide range of substrate combinations. Effective pronucleophiles include oxazolones, 2-furanone, nitroalkanes, pyrroles, 3-hydroxyoxindoles, alkynes, meso-1,3-diols, and dialkyl phosphine oxides. These substrates were found to be effective with a number of electrophiles, including aldehydes, imines, nitroalkenes, acyl silanes, vinyl benzoates, and α,β-unsaturated carbonyls. A truly diverse range of enantioenriched compounds have been prepared using the ProPhenol ligand, and the commercial availability of both ligand enantiomers makes it ideally suited for the synthesis of complex molecules. To date, enantioselective ProPhenol-catalyzed reactions have been used in the synthesis of more than 20 natural products. PMID:25650587

Novel electrode structure in a DBD reactor applied to the degradation of phenol in aqueous solution

NASA Astrophysics Data System (ADS)

Mercado-Cabrera, Antonio; Peña-Eguiluz, Rosendo; López-Callejas, Régulo; Jaramillo-Sierra, Bethsabet; Valencia-Alvarado, Raúl; Rodríguez-Méndez, Benjamín; Muñoz-Castro, Arturo E.

2017-07-01

Phenol degradation experimental results are presented in a similar wastewater aqueous solution using a non-thermal plasma reactor in a coaxial dielectric barrier discharge. The novelty of the work is that one of the electrodes of the reactor has the shape of a hollow screw which shows an enhanced efficiency compared with a traditional smooth structure. The experimentation was carried out with gas mixtures of 90% Ar-10% O2, 80% Ar-20% O2 and 0% Ar-100% O2. After one hour of treatment the removal efficiency was 76%, 92%, and 97%, respectively, assessed with a gas chromatographic mass spectrometry technique. For both reactors used, the ozone concentration was measured. The screw electrode required less energy, for all gas mixtures, than the smooth electrode, to maintain the same ozone concentration. On the other hand, it was also observed that in both electrodes the electrical conductivity of the solution changed slightly from ˜0.0115 S m-1 up to ˜0.0430 S m-1 after one hour of treatment. The advantages of using the hollow screw electrode structure compared with the smooth electrode were: (1) lower typical power consumption, (2) the generation of a uniform plasma throughout the reactor benefiting the phenol degradation, (3) a relatively lower temperature of the aqueous solution during the process, and (4) the plasma generation length is larger.

Structure and fertilizer properties of byproducts formed in the synthesis of EDDHA.

PubMed

Hernández-Apaolaza, Lourdes; García-Marco, Sonia; Nadal, Paloma; Lucena, Juan J; Sierra, Miguel A; Gómez-Gallego, Mar; Ramírez-López, Pedro; Escudero, Rosa

2006-06-14

The synthesis of commercial EDDHA produces o,o-EDDHA as the main reaction product, together with a mixture of regioisomers (o,p-EDDHA and p,p-EDDHA) and other unknown byproducts also able to complex Fe3+. These compounds have been obtained by direct synthesis, and their structures have been determined by ESI-MS analysis as oligomeric EDDHA-like products, formed by polysubstitution in the phenolic rings. Short-term experiments show that the iron complexes of samples enriched in these oligomeric byproducts have adequate stability in solution, but a significant amount of them is lost after interaction with soils and soil materials. Mildly chlorotic cucumber plants are able to reduce iron better from o,p-EDDHA/Fe3+ than from the iron complexes of the oligomeric byproducts. In hydroponics, the chlorotic soybean susceptible plants have a lower potential for Fe absorption from these byproducts than from o,o-EDDHA/Fe3+ and from o,p-EDDHA/Fe3+. In the studied conditions, the iron chelates of EDDHA byproducts do not have the long-lasting effect shown by o,o-EDDHA/Fe3+ and present a less efficient fast-action effect than the o,p-EDDHA/Fe3+.

Comprehensive polyphenol profiling of a strawberry extract (Fragaria × ananassa) by ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry.

PubMed

La Barbera, Giorgia; Capriotti, Anna Laura; Cavaliere, Chiara; Piovesana, Susy; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2017-03-01

The aim of metabolic untargeted profiling is to detect and identify unknown compounds in a biological matrix to achieve the most comprehensive metabolic coverage. In phytochemical mixtures, however, the complexity of the sample could present significant difficulties in compound identification. In this case, the optimization of both the chromatographic and the mass-spectrometric conditions is supposed to be crucial for the detection and identification of the largest number of compounds. In this work, a systematic investigation of different chromatographic and mass-spectrometric conditions is presented to achieve a comprehensive untargeted profiling of a strawberry extract (Fragaria × ananassa). To fulfill this aim, an ultra-high-pressure liquid chromatography system coupled via an electrospray source to a hybrid quadrupole-Orbitrap mass spectrometer was used. Spectra were acquired in data-dependent mode, and several parameters were investigated to acquire the largest possible number of both mass spectrometry (MS) features and MS 2 mass spectra for unique metabolites. The main classes of polyphenols studied were flavonoids, phenolic acids, dihydrochalcones, ellagitannins, and proanthocyanidins. Method optimization allowed to us identify and tentatively identify 18 and 113 compounds, respectively, among which 74 have never been reported before in strawberries and, to the best of our knowledge, 22 of them have never been reported before. The results show the importance of an extended investigation of the chromatographic and mass-spectrometric method before a complete untargeted profiling of complex phytochemical mixtures.

Environmental nitration processes enhance the mutagenic potency of aromatic compounds.

PubMed

Bonnefoy, Aurélie; Chiron, Serge; Botta, Alain

2012-05-01

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012. Copyright © 2010 Wiley Periodicals, Inc.

Reaction of CO2 with propylene oxide and styrene oxide catalyzed by a chromium(III) amine-bis(phenolate) complex.

PubMed

Dean, Rebecca K; Devaine-Pressing, Katalin; Dawe, Louise N; Kozak, Christopher M

2013-07-07

A diamine-bis(phenolate) chromium(III) complex, {CrCl[O2NN'](BuBu)}2 catalyzes the copolymerization of propylene oxide with carbon dioxide. The synthesis of this metal complex is straightforward and it can be obtained in high yields. This catalyst incorporates a tripodal amine-bis(phenolate) ligand, which differs from the salen or salan ligands typically used with Cr and Co complexes that have been employed as catalysts for the synthesis of such polycarbonates. The catalyst reported herein yields low molecular weight polymers with narrow polydispersities when the reaction is performed at room temperature. Performing the reaction at elevated temperatures causes the selective synthesis of propylene carbonate. The copolymerization activity for propylene oxide and carbon dioxide, as well as the coupling of carbon dioxide and styrene oxide to give styrene carbonate are presented.

DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

Kinetics on cocondensation between phenol and urea through formaldehyde I

Treesearch

Yasunori Yoshida; Bunchiro Tomita; Chung-Yun Hse

1995-01-01

The kinetics of the reactions of methylolphenols and urea were investigated using 2- and 4-hydroxybenzyl alcohols. The high-performance liquid chromatography (HPLC) using a reverse-phase column gave a clear separation between methylolphenols and hydroxybenzylureas. The molar ratios of hydroxybenzylureas to the corresponding methylolphenols in reaction mixtures were...

Kinetics on cocondensation between phenol and urea through formaldehyde I.

Treesearch

Yasunori Yoshida; Bunichiro Tomita; Chung-Yun Hse

1995-01-01

The kinetics of the ractions of methylolphenols and urea were investigated using 2- and 4- hydroxybenzyl alcohols. The high-performance liquid chromatogrpahy (HPLC) using a reverse-phase column gave a clear separation between methylolphenols and hydroxybenzylureas. The molar ratios of hydroxybenzylureas to be corresponding methylolphenols in reaction mixtures were...

DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

Method of Preparing Polymers with Low Melt Viscosity

NASA Technical Reports Server (NTRS)

Jensen, Brian J. (Inventor)

2001-01-01

This invention is an improvement in standard polymerizations procedures, i.e., addition-type and step-growth type polymerizations, wherein monomers are reacted to form a growing polymer chain. The improvement includes employing an effective amount of a trifunctional monomer (such as a trifunctional amine anhydride, or phenol) in the polymerization procedure to form a mixture of polymeric materials consisting of branced polymers, star-shaped polymers, and linear polymers. This mixture of polymeric materials has a lower melt temperature and a lower melt viscosity than corresponding linear polymeric materials of equivalent molecular weight.

[Simple method for precognition of drug interaction between oral iron and phenolic hydroxyl group-containing drugs].

PubMed

Sunagane, Nobuyoshi; Yoshinobu, Etsuko; Murayama, Nobuko; Terawaki, Yasufumi; Kamimura, Naoki; Uruno, Tsutomu

2005-02-01

In the present study, we devised a simple method for detecting the drug interaction between oral iron preparations and phenolic hydroxyl group-containing drugs, using the coloring reaction as indicator, due to the formation of complexes or chelates. In the method, oral iron preparations and test drugs in amounts as much as single dose for adults were added to 10 ml of purified water to make sample suspensions for testing. Thirty minutes after mixing an oral iron suspension and a test drug suspension, the change of color in the mixture was observed macroscopically and graded as 0 to 3, with a marked color change judged as grade 3 and no color change as grade 0. Screening of 14 test drugs commonly used orally was carried out. When using sodium ferrous citrate preparations as oral iron, 5 were classified as grade 3, 2 as grade 2, 4 as grade 1, and 3 as grade 0, respectively. To verify usefulness of the method, the interactions suggested by screening were pharmacokinetically assessed by measuring serum concentrations of the drug in mice. When a levodopa or droxidopa preparation, judged as grade 3 in screening, was concomitantly administered with an iron preparation, a significant reduction in bioavailability of the test drug was observed, indicating possible drug interaction between the test drug and oral iron. Combined administration of an acetaminophen preparation, judged as grade 1, and oral iron preparation showed no influence on the bioavailability of the test drug, implying no detectable interactions between them. In conclusion, the simple method devised in the present study is useful for precognition of drug interactions between oral iron preparations and phenolic hydroxyl group-containing drugs, and the drugs with a higher grade in screening may induce drug interactions with oral iron.

Phenol-selective mass spectrometric analysis of jet fuel.

PubMed

Zhu, Haoxuan; Janusson, Eric; Luo, Jingwei; Piers, James; Islam, Farhana; McGarvey, G Bryce; Oliver, Allen G; Granot, Ori; McIndoe, J Scott

2017-08-21

Bromobenzyl compounds react selectively with phenols via the Williamson ether synthesis. An imidazolium charge-tagged bromobenzyl compound can be used to reveal phenol impurities in jet fuel by analysis via electrospray ionization mass spectrometry. The complex matrix as revealed by Cold EI GC/MS analysis is reduced to a few simple sets of compounds in the charge-tagged ESI mass spectrum, primarily substituted phenols and thiols. Examination of jet fuels treated by different refinery methods reveals the efficacy of these approaches in removing these contaminants.

Tailored Design of Bicontinuous Gyroid Mesoporous Carbon and Nitrogen-Doped Carbon from Poly(ethylene oxide-b-caprolactone) Diblock Copolymers.

PubMed

Chu, Wei-Cheng; Bastakoti, Bishnu Prasad; Kaneti, Yusuf Valentino; Li, Jheng-Guang; Alamri, Hatem R; Alothman, Zeid A; Yamauchi, Yusuke; Kuo, Shiao-Wei

2017-10-04

Highly ordered mesoporous resol-type phenolic resin and the corresponding mesoporous carbon materials were synthesized by using poly(ethylene oxide-b-caprolactone) (PEO-b-PCL) diblock copolymer as a soft template. The self-assembled mesoporous phenolic resin was found to form only in a specific resol concentration range of 40-70 wt % due to an intriguing balance of hydrogen-bonding interactions in the resol/PEO-b-PCL mixtures. Furthermore, morphological transitions of the mesostructures from disordered to gyroid to cylindrical and finally to disordered micelle structure were observed with increasing resol concentration. By calcination under nitrogen atmosphere at 800 °C, the bicontinuous mesostructured gyroid phenolic resin could be converted to mesoporous carbon with large pore size without collapse of the original mesostructure. Furthermore, post-treatment of the mesoporous gyroid phenolic resin with melamine gave rise to N-doped mesoporous carbon with unique electronic properties for realizing high CO 2 adsorption capacity (6.72 mmol g -1 at 0 °C). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

PubMed

Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

2016-06-29

A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

Phenol Contaminated Water Treatment on Several Modified Dimensionally Stable Anodes.

PubMed

Jayathilaka, Pavithra Bhakthi; Hapuhinna, Kushani Umanga Kumari; Bandara, Athula; Nanayakkara, Nadeeshani; Subasinghe, Nalaka Deepal

2017-08-01

  Phenolic compounds are some of the most common hazardous organics in wastewater. Removal of these pollutants is important. Physiochemical method such as electrochemical oxidation on dimensionally stable anodes is more convenient in removing such organic pollutants. Therefore, this study focuses on development of three different anodes for phenol contaminated water treatment. The performances of steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes were tested and compared. Nearly 50, 76, and 84% of chemical oxygen demand removal efficiencies were observed for steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes, respectively. The formation of intermediates was monitored for three anodes and the Ti/IrO2-Sb2O3 anode showed the most promising results. Findings suggest that the developed anode materials can enhance phenol oxidation efficiency and that mixed metal oxide layer has major influence on the anode. Among the selected metal oxide mixtures IrO2-Sb2O3 was the most suitable under given experimental conditions.

Multicentre patch testing with a resol resin based on phenol and formaldehyde.

PubMed

Isaksson, Marléne; Inerot, Annica; Lidén, Carola; Matura, Mihaly; Stenberg, Berndt; Möller, Halvor; Bruze, Magnus

2011-07-01

Contact allergy to phenol-formaldehyde resins (PFRs) based on phenol and formaldehyde is not detected by a p-tertiary-butylphenol-formaldehyde resin (PTBP-FR) included in most baseline patch test series. To investigate the rate of contact allergy to PFR-2 (a mixture of monomers and dimers from a resol resin based on phenol and formaldehyde) in a Swedish population, and to investigate associated simultaneous allergic reactions. Five centres representing the Swedish Contact Dermatitis Research Group included PFR-2 in their patch test baseline series for a period of 1.5 years. Of 2504 patients tested, 27 (1.1%) reacted to PFR-2. Of those 27 individuals, 2 had a positive reaction to formaldehyde and 2 to PTBP-FR. Simultaneous allergic reactions were noted to colophonium in 6, to Myroxylon pereirae in 14, and to fragrance mix I in 15. The contact allergy frequency in the tested population (1.1%) merits its inclusion in the Swedish baseline series and possibly also in other baseline series. Simultaneous allergic reactions were noted to colophonium, M. pereirae, and fragrance mix I. © 2011 John Wiley & Sons A/S.

Phenolic aminocarboxylic acids as gallium-binding radiopharmaceuticals.

PubMed

Hunt, F C

1984-06-01

The phenolic aminocarboxylic acids ethylenediamine di [o-hydroxyphenylacetic acid] (EDDHA) and N,N'-bis [2-hydroxybenzyl] ethylenediamine N,N'-diacetic acid (HBED) form gallium complexes having high stability constants which enable them to resist exchange of gallium with plasma transferrin. 67Ga complexes were synthesized with these ligands, placing substituent groups in the phenolic ring to direct excretion via the renal or hepatobiliary route. The amount of 67Ga-Br-EDDHA excreted via the hepatobiliary route was comparable with that of some of the 99mTc agents. Excretion of 67Ga-Br-HBED was similar but with delayed transit from the liver. 67Ga COOH-EDDHA was excreted exclusively via the renal route. These findings provide a basis for developing new 67Ga or 68Ga radiopharmaceuticals, the latter for use in positron emission tomography, using these phenolic aminocarboxylates.

Hydroxychavicol: a new anti-nitrosating phenolic compound from betel leaf.

PubMed

Nagabhushan, M; Amonkar, A J; Nair, U J; D'Souza, A V; Bhide, S V

1989-05-01

Hydroxychavicol and eugenol are the phenolic compounds isolated from betel leaf (piper betel). The modulation of nitrosation of methylurea by sodium nitrite at pH 3.6 and 30 degrees C was studied. The formation of mutagenic N-nitrosomethylurea was monitored by checking the mutagenicity of reaction mixture in Salmonella typhimurium strain TA100 and TA1535 without S9 mix. Hydroxychavicol and eugenol exhibit dose-dependent suppression of nitrosation in vitro without affecting the survival of the bacteria. Pre- or post-treatment of bacterial cells from S. typhimurium strains TA100 and TA1535 with phenolics did not modify the mutagenicity of nitrosomethylurea. The blocking of hydroxy group(s) in the benzene ring by acetylation abolishes the anti-nitrosating activity of the molecule(s). The nitrosation inhibition by hydroxychavicol is through scavenging of nitrite ions in the media, thus making them non-available for the nitrosation of methylurea.

Topical or oral treatment of peach flower extract attenuates UV-induced epidermal thickening, matrix metalloproteinase-13 expression and pro-inflammatory cytokine production in hairless mice skin

PubMed Central

Yang, Jiwon; Shin, Chang-Yup; Chung, Jin Ho

2018-01-01

BACKGROUND/OBJECTIVES Ultraviolet radiation (UV) is a major cause of skin photoaging. Previous studies reported that ethanol extract (PET) of Prunus persica (L.) Batsch flowers (PPF, peach flowers) and its subfractions, particularly the ethylacetate (PEA) and n-butanol extracts (PBT), have potent antioxidant activity and attenuate the UV-induced matrix metalloproteinase (MMP) expression in human skin cells. In this study, we investigated the protective activity of PPF extract against UV-induced photoaging in a mouse model. MATERIALS/METHODS Hairless mice were treated with PET or a mixture of PEA and PBT either topically or orally along with UV irradiation. Histological changes and biochemical alterations of mouse skin were examined. Major phenolic compounds in PPF extract were analyzed using an ACQUITY UPLC system. RESULTS The overall effects of topical and oral treatments with PPF extract on the UV-induced skin responses exhibited similar patterns. In both experiments, the mixture of PEA and PBT significantly inhibited the UV-induced skin and epidermal thickening, while PET inhibited only the UV-induced epidermal thickening. Treatment of PET or the mixture of PEA and PBT significantly inhibited the UV-induced MMP-13 expression, but not typeⅠ collagen expression. Topical treatment of the mixture of PEA and PBT with UV irradiation significantly elevated catalase, superoxide dismutase (SOD) and glutathione-peroxidase (GPx) activities in the skin compared to those in the UV irradiated control group, while oral treatment of the mixture of PEA and PBT or PET elevated only catalase and SOD activities, but not GPx. Thirteen phytochemical compounds including 4-O-caffeoylquinic acid, cimicifugic acid E and B, quercetin-3-O-rhamnoside and kaempferol glycoside derivatives were identified in the PPF extract. CONCLUSIONS These results demonstrate that treatment with PET or the mixture of PEA and PBT, both topically or orally, attenuates UV-induced photoaging via the cooperative interactions of phenolic components having anti-oxidative and collagen-protective activities. PMID:29399294

Chemical characterization and effects on Lepidium sativum of the native and bioremediated components of dry olive mill residue.

PubMed

Aranda, E; García-Romera, I; Ocampo, J A; Carbone, V; Mari, A; Malorni, A; Sannino, F; De Martino, A; Capasso, R

2007-09-01

Dry olive mill residue (DOR) from the olive oil production by two phase centrifugation system was fractionated by a consecutive continuous solid-liquid extraction obtaining the EAF, PF, MF and WF fractions with ethyl acetate, n-propanol, methanol and water, respectively. The chemical, chromatographic and mass spectrometric analyses showed EAF, PF and MF to be mainly composed of simple phenols, phenolic acids, flavonoids and glycosilated phenols (glycosides of phenols, secoiridoids and flavonoids), whereas WF was mainly consisting of polymerin, the metal organic polymeric mixture previously identified in olive oil mill waste waters and composed of carbohydrates, melanin, proteins and metals (K, Na, Ca, Mg and Fe). The identification in DOR of oleoside, 6'-beta-glucopyranosyl-oleoside and 6'-beta-rhamnopyranosyl-oleoside, and of its organic polymeric component, known as polymerin, are reported for the first time in this paper. The inoculation of the previously mentioned fractions with saprobe fungi Coriolopsis rigida, Pycnoporus cynnabarinus or Trametes versicolor indicated these fungi to be able to metabolize both the phenols and glycosilated phenols, but not polymerin. In correspondence, EAF, PF, MF and WF, which proved to be toxic on Lepidium sativum, decreased their toxicity after incubation with the selected fungi, WF showing to be also able to stimulate the growth of the selected seeds. The phytotoxicity appeared mainly correlated to the monomeric phenols and, to a lesser extent, to the glycosilated phenols, whereas polymerin proved to be non toxic. However, the laccase activity was not associated with the decrease of phytotoxicity. The valorization of DOR as a producer of high added value substances of industrial and agricultural interest in native form and after their bioremediation for a final objective of the total DOR recycling is also discussed.

Determination of phenol, m-, o- and p-cresol, p-aminophenol and p-nitrophenol in urine by high-performance liquid chromatography.

PubMed

Brega, A; Prandini, P; Amaglio, C; Pafumi, E

1990-12-28

A method for the biological monitoring of human exposure to aromatic hydrocarbons, nitrocompounds, amines and phenols has been developed. Phenol, cresols, p-aminophenol, p-nitrophenol and their glucorono- or sulpho-conjugates, were quantified by HPLC; 4-chlorphenol was added as internal standard. After enzymatic hydrolysis, the free compounds were extracted with an organic solvent and analyzed by an isocratic HPLC Perkin Elmer system at ambient temperature and at a flow-rate of 1 ml/min. The column was a reversed-phase Pecosphere 3 x 3 C18 Perkin Elmer; the mobile phase was a 30:70:0.1 (v/v/v) methanol-water-orthophosphoric acid mixture and the chromatogram was monitored at 215 nm. Identification was based on retention time and quantification was performed by automatic peak height determination, corrected for the internal standard. The recovery was ca. 95% for phenol and cresols; 90% for p-nitrophenol; 85% for p-aminophenol; the coefficients of variance were less than 6% within analysis (n = 20) and less than 10% between analysis (n = 20). The detection limits, at a signal/noise ratio of 2, were 0.5 mg/l for phenol and cresols and 1 mg/l for p-aminophenol and p-nitrophenol.

Simultaneous Removal of Phenol and Dissolved Solids from Wastewater Using Multichambered Microbial Desalination Cell.

PubMed

Pradhan, Harapriya; Jain, Sumat Chand; Ghangrekar, Makarand M

2015-12-01

Microbial desalination cell (MDC) has great potential toward direct electricity generation from wastewater and concurrent desalination through potential difference developed due to microbial activity. Degradation of phenol by isolate Pseudomonas aeruginosa in anodic chamber and simultaneous desalination of water in middle desalination chamber of multichamber MDC is demonstrated in this study. Performance of the MDCs with different anodic inoculum conditions, namely pure culture of P. aeruginosa (MDC-1), 50 % v/v mixture of P. aeruginosa and anaerobic mixed consortia (MDC-2) and anaerobic mixed consortia (MDC-3), was evaluated to compare the phenol degradation in anodic chamber, bioelectricity generation, and simultaneous total dissolved solids (TDS) removal from saline water in desalination chamber. Synergistic effect between P. aeruginosa and mixed anaerobic consortia as inoculum was evident in MDC-2 demonstrating phenol degradation of 90 %, TDS removal of 75 % in 72 h of reaction time along with higher power generation of 27.5 mW/m(2) as compared to MDC-1 (95 %, 64 %, 12.8 mW/m(2), respectively) and MDC-3 (58 %, 52 %, 4.8 mW/m(2), respectively). The results illustrate that the multichamber MDC-2 is effective for simultaneous removal of phenol and dissolved solids contained in industrial wastewaters.

Steam reforming of fast pyrolysis-derived aqueous phase oxygenates over Co, Ni, and Rh metals supported on MgAl 2O 4

DOE PAGES

Xing, Rong; Dagle, Vanessa Lebarbier; Flake, Matthew; ...

2016-02-03

In this paper we examine the feasibility of steam reforming the mixed oxygenate aqueous fraction derived from fast pyrolysis bio-oils. Catalysts selective towards hydrogen formation and resistant to carbon formation utilizing feeds with relatively low steam-to-carbon (S/C) ratios are desired. Rh (5 wt%), Pt (5 wt%), Ru (5 wt%), Ir (5 wt%), Ni (15 wt%), and Co (15 wt%) metals supported on MgAl2O4 were evaluated for catalytic performance at 500 °C and 1 atm using a complex feed mixture comprising acids, polyols, cycloalkanes, and phenolic compounds. The Rh catalyst was found to be the most active and resistant to carbonmore » formation. The Ni and Co catalysts were found to be more active than the other noble metal catalysts investigated (Pt, Ru, and Ir).« less

Use of the intestinal parasite community of Sigmodon hispidus as a biomonitor in terrestrial systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faulkner, B.C.; Lochmiller, R.L.

1995-12-31

The goal of this study was to assess the potential usefulness of parasite communities of small mammals as an endpoint for community level risk assessment in terrestrial ecosystems. A total of 350 wild cotton rats (Sigmodon hispidus) were collected from a Superfund site in southwestern Oklahoma between fall 1993 and fall 1995. Three contaminated study sites, representing common petrochemical disposal methods and all containing complex mixtures of contaminants, including arsenic, lead, fluoride, phenols, and hydrocarbons, were monitored seasonally. Animals were collected and gastrointestinal contents were examined grossly and microscopically for helminths and coccidial parasites. All parasites were identified to speciesmore » and enumerated so that measurable alterations of the parasite community structure could be established. The authors also sampled possible intermediate host communities concurrently with Sigmodon collections. Structural characteristics of the parasite communities were compared between replicated toxic and reference study sites.« less

Investigation of Phenols Activity in Early Stage Oxidation of Edible Oils by Electron Paramagnetic Resonance and 19F NMR Spectroscopies Using Novel Lipid Vanadium Complexes As Radical Initiators.

PubMed

Drouza, Chryssoula; Dieronitou, Anthi; Hadjiadamou, Ioanna; Stylianou, Marios

2017-06-21

A novel dynamic method for the investigation of the phenols activity in early stage oxidation of edible oils based on the formation of α-tocopheryl radicals initiated by oil-soluble vanadium complexes is developed. Two new vanadium complexes in oxidation states V and IV were synthesized by reacting 2,2'-((2-hydroxyoctadecyl)azanediyl)bis(ethan-1-ol) (C18DEA) with [VO(acac) 2 ] and 1-(bis(pyridin-2-ylmethyl)amino)octadecan-2-ol (C18DPA) with VOCl 2 . Addition of a solution of either complex in edible oils resulted in the formation of α-tocopheryl radical, which was monitored by electron paramagnetic resonance (EPR) spectroscopy. The intensity of the α-tocopheryl signal in the EPR spectra was measured versus time. It was found that the profile of the intensity of the α-tocopheryl signal versus time depends on the type of oil, the phenolic content, and the storage time of the oil. The time interval until the occurrence of maximum peak intensity be reached (t m ), the height of the maximum intensity, and the rate of the quenching of the α-tocopheryl radical were used for the investigation of the mechanism of the edible oils oxidation. 19 F NMR of the 19 F labeled phenolic compounds (through trifluoroacetate esters) and radical trap experiments showed that the vanadium complexes in edible oil activate the one electron reduction of dioxygen to superperoxide radical. Superperoxide reacts with the lipids to form alkoperoxyl and alkoxyl lipid radicals, and all these radicals react with the phenols contained in oils.

The lignin component of humic substances: Distribution among soil and sedimentary humic, fulvic, and base-insoluble fractions

NASA Astrophysics Data System (ADS)

Ertel, John R.; Hedges, John I.

1984-10-01

Vanillyl, syringyl and cinnamyl phenols occur as CuO oxidation products of humic, fulvic and base-insoluble residual fractions from soils, peat and nearshore marine sediments. However, none of these lignin-derived phenols were released by CuO oxidation of deepsea sediment or its base-extractable organic fractions. Lignin analysis indicated that peat and coastal marine sediments contained significantly higher levels of recognizable vascular plant carbon (20-50%) than soils and offshore marine sediments (0-10%). Although accounting for less than 20% of the total sedimentary (bulk) lignin, lignin components of humic acid fractions compositionally and quantitatively resembled the corresponding bulk samples and baseinsoluble residues. Recognizable lignin, presumably present as intact phenylpropanoid units, accounted for up to 5% of the carbon in peat and coastal humic acids but less than 1% in soil humic acids. Fulvic acid fractions uniformly yielded less lignin-derived phenols in mixtures that were depleted in syringyl and cinnamyl phenols relative to the corresponding humic acid fractions. Within the vanillyl and syringyl families the relative distribution of acidic and aldehydic phenols is a sensitive measure of the degree of oxidative alteration of the lignin component The high acid/aldehyde ratios and the low phenol yields of soils and their humic fractions compared to peat and coastal sediments indicate extensive degradation of the lignin source material. Likewise, the progressively higher acid/aldehyde ratios and lower phenol yields along the sequence: plant tissues (plant debris)-humic acids-fulvic acids suggest that this pattern represents the diagenetic sequence for the aerobic degradation of lignin biopolymers.

77 FR 41692 - Significant New Use Rule for Phenol, 2,4- dimethyl-6-(1-methylpentadecyl)-

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-16

... visitors are required to show photographic identification, pass through a metal detector, and sign the EPA... often used as an additive in thermoplastic polymer matrices and in mixtures at concentrations less than... matrices. 5. Revises the recordkeeping requirements under Sec. 721.125 to reflect the modified significant...

Phylogenetic and functional diversity of metagenomic libraries of phenol degrading sludge from petroleum refinery wastewater treatment system.

PubMed

Silva, Cynthia C; Hayden, Helen; Sawbridge, Tim; Mele, Pauline; Kruger, Ricardo H; Rodrigues, Marili Vn; Costa, Gustavo Gl; Vidal, Ramon O; Sousa, Maíra P; Torres, Ana Paula R; Santiago, Vânia Mj; Oliveira, Valéria M

2012-03-27

In petrochemical refinery wastewater treatment plants (WWTP), different concentrations of pollutant compounds are received daily in the influent stream, including significant amounts of phenolic compounds, creating propitious conditions for the development of particular microorganisms that can rapidly adapt to such environment. In the present work, the microbial sludge from a refinery WWTP was enriched for phenol, cloned into fosmid vectors and pyrosequenced. The fosmid libraries yielded 13,200 clones and a comprehensive bioinformatic analysis of the sequence data set revealed a complex and diverse bacterial community in the phenol degrading sludge. The phylogenetic analyses using MEGAN in combination with RDP classifier showed a massive predominance of Proteobacteria, represented mostly by the genera Diaphorobacter, Pseudomonas, Thauera and Comamonas. The functional classification of phenol degrading sludge sequence data set generated by MG-RAST showed the wide metabolic diversity of the microbial sludge, with a high percentage of genes involved in the aerobic and anaerobic degradation of phenol and derivatives. In addition, genes related to the metabolism of many other organic and xenobiotic compounds, such as toluene, biphenyl, naphthalene and benzoate, were found. Results gathered herein demonstrated that the phenol degrading sludge has complex phylogenetic and functional diversities, showing the potential of such community to degrade several pollutant compounds. This microbiota is likely to represent a rich resource of versatile and unknown enzymes which may be exploited for biotechnological processes such as bioremediation.

Synergy of antibacterial and antioxidant activities from crude extracts and peptides of selected plant mixture

PubMed Central

2013-01-01

Background A plant mixture containing indigenous Australian plants was examined for synergistic antimicrobial activity using selected test microorganisms. This study aims to investigate antibacterial activities, antioxidant potential and the content of phenolic compounds in aqueous, ethanolic and peptide extracts of plant mixture. Methods Well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were used to test antibacterial activity against four pathogenic bacteria namely Staphylococcus aureus, Escherichia coli, Bacillus cereus, and Pseudomonas aeruginosa. DPPH (2, 2-diphenyl-1- picrylhydrazyl) and superoxide dismutase (SOD) assays were used to evaluate antioxidant activity. HPLC and gel filtration were used for purification of the peptides. Scanning electron microscope was applied to investigate the mode of attachment of the peptides on target microbial membranes. Results Aqueous extraction of the mixture showed no inhibition zones against all the test bacteria. Mean diameter of inhibition zones for ethanol extraction of this mixture attained 8.33 mm, 7.33 mm, and 6.33 mm against S. aureus at corresponding concentrations of 500, 250 and 125 mg/ml while E .coli showed inhibition zones of 9.33 mm, 8.00 mm and 6.66 mm at the same concentrations. B. cereus exhibited inhibition zones of 11.33 mm, 10.33 mm and 10.00 mm at concentrations of 500, 250 and 125 mg/ml respectively. The peptide extract demonstrated antibacterial activity against S. aureus, E. coli and B. cereus. The MIC and MBC values for ethanol extracts were determined at 125 mg/ml concentration against S. aureus and E. coli and B. cereus value was 31.5 mg/ml. MIC and MBC values showed that the peptide extract was significantly effective at low concentration of the Australian plant mixture (APM). Phenolic compounds were detected in hot aqueous and ethanolic extracts of the plant mixture. Hot aqueous, ethanol and peptides extracts also exhibited antioxidant activities. Conclusions It was concluded that APM possessed good antibacterial and antioxidant activities following extraction with different solvents. The results suggest that APM provide a new source with antibacterial agents and antioxidant activity for nutraceutical or medical applications. PMID:24330547

Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol.

PubMed

Hristova, Krassimira R; Schmidt, Radomir; Chakicherla, Anu Y; Legler, Tina C; Wu, Janice; Chain, Patrick S; Scow, Kate M; Kane, Staci R

2007-11-01

High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

Pilot-plant evaluation of TiO2 and TiO2-based hybrid photocatalysts for solar treatment of polluted water.

PubMed

Andronic, Luminita; Isac, Luminita; Miralles-Cuevas, Sara; Visa, Maria; Oller, Isabel; Duta, Anca; Malato, Sixto

2016-12-15

Materials with photocatalytic and adsorption properties for advanced wastewater treatment targeting reuse were studied. Making use of TiO 2 as a well-known photocatalyst, Cu 2 S as a Vis-active semiconductor, and fly ash as a good adsorbent, dispersed mixtures/composites were prepared to remove pollutants from wastewater. X-ray diffraction, scanning electron microscopy, energy-dispersive X-Ray spectroscopy, atomic force microscopy, band gap energy, point of zero charge (pH pzc ) and BET porosity were used to characterize the substrates. Phenol, imidacloprid and dichloroacetic acid were used as pollutants for photocatalytic activity of the new photocatalysts. Experiments using the new dispersed powders were carried out at laboratory scale in two solar simulators and under natural solar irradiation at the Plataforma Solar de Almería, in a Compound Parabolic Collector (CPC) for a comparative analysis of pollutants removal and mineralization efficiencies, and to identify features that could facilitate photocatalyst separation and reuse. The results show that radiation intensity significantly affects the phenol degradation rate. The composite mixture of TiO 2 and fly ash is 2-3 times less active than sol-gel TiO 2 . Photodegradation kinetic data on the highly active TiO 2 are compared for pollutants elimination. Photodegradation of dichloroacetic acid was fast and complete after 90min in the CPC, while after 150min imidacloprid and phenol removal was 90% and 56% respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface reactions of iron - enriched smectites: adsorption and transformation of hydroxy fatty acids and phenolic acids

NASA Astrophysics Data System (ADS)

Polubesova, Tamara; Olshansky, Yaniv; Eldad, Shay; Chefetz, Benny

2014-05-01

Iron-enriched smectites play an important role in adsorption and transformation of soil organic components. Soil organo-clay complexes, and in particular humin contain hydroxy fatty acids, which are derived from plant biopolymer cutin. Phenolic acids belong to another major group of organic acids detected in soil. They participate in various soil processes, and are of concern due to their allelopathic activity. We studied the reactivity of iron-enriched smectites (Fe(III)-montmorillonite and nontronite) toward both groups of acids. We used fatty acids- 9(10),16-dihydroxypalmitic acid (diHPA), isolated from curtin, and 9,10,16-trihydroxypalmitic acid (triHPA); the following phenolic acids were used: ferulic, p-coumaric, syringic, and vanillic. Adsorption of both groups of acids was measured. The FTIR spectra of fatty acid-mineral complexes indicated inner-sphere complexation of fatty acids with iron-enriched smectites (versus outer-sphere complexation with Ca(II)-montmorillonite). The LC-MS results demonstrated enhanced esterification of fatty acids on the iron-enriched smectite surfaces (as compared to Ca(II)-montmorillonite). This study suggests that fatty acids can be esterified on the iron-enriched smectite surfaces, which results in the formation of stable organo-mineral complexes. These complexes may serve as a model for the study of natural soil organo-clay complexes and humin. The reaction of phenolic acids with Fe(III)-montmorillonite demonstrated their oxidative transformation by the mineral surfaces, which was affected by molecular structure of acids. The following order of their transformation was obtained: ferulic >syringic >p-coumaric >vanillic. The LC-MS analysis demonstrated the presence of dimers, trimers, and tetramers of ferulic acid on the surface of Fe(III)-montmorillonite. Oxidation and transformation of ferulic acid were more intense on the surface of Fe(III)-montmorillonite as compared to Fe(III) in solution due to stronger complexation on the Fe(III)-motnomrillonite surface. Our study demonstrate the importance of iron-enriched minerals for the abiotic formation of humic materials and for the transformation of aromatic (phenolic) pollutants.

Degradation of phenolic contaminants in ground water by anaerobic bacteria: St. Louis Park, Minnesota

USGS Publications Warehouse

Ehrlich, G.G.; Goerlitz, D.F.; Godsy, E.M.; Hult, M.F.

1982-01-01

Coal-tar derivatives from a coal-tar distillation and wood-treating plant that operated from 1918 to 1972 at St. Louis Park, Minnesota contaminated the near-surface ground water. Solutions of phenolic compounds and a water-immiscible mixture of polynuclear aromatic compounds accumulated in wetlands near the plant site and entered the aquifer. The concentration of phenolic compounds in the aqueous phase under the wetlands is about 30 mg/1 but decreases to less than 0.2 mg/1 at a distance of 430 m immediately downgradient from the source. Concentrations of naphthalene (the predominant polynuclear compound in the ground water) and sodium (selected as a conservative tracer) range from about 20 mg/1 and 430 mg/1 in the aqueous phase at the source to about 2 mg/1 and 120 mg/1 at 430 m downgradient, respectively. Phenolic compounds and naphthalene are disappearing faster than expected if only dilution were occurring. Sorption of phenolic compounds on aquifer sediments is negligible but naphthalene is slightly sorbed. Anaerobic biodegradation of phenolic compounds is primarily responsible for the observed attenuation. Methane was found only in water samples from the contaminated zone (2-20 mg/1). Methane-producing bacteria were found only in water from the contaminated zone. Methane was produced in laboratory cultures of contaminated water inoculated with bacteria from the contaminated zone. Evidence for anaerobic biodegradation of naphthalene under either field or laboratory conditions was not obtained.

Effect of a chemical mixture on dermal penetration of arsenic and nickel in male pig in vitro.

PubMed

Turkall, Rita M; Skowronski, Gloria A; Suh, Duck H; Abdel-Rahman, Mohamed S

2003-04-11

The effect of a chemical mixture on the dermal penetration of arsenic or nickel was assessed by applying arsenic-73 or nickel-63 alone or with the chemical mixture to dermatomed male pig skin samples in flow-through diffusion cells. The chemical mixture consisted of chloroform, phenanthrene, and toluene for arsenic penetration studies and phenol, toluene, and trichloroethylene (TCE) for nickel studies. These are predominant chemicals found at hazardous waste sites. Arsenic and nickel bind to skin after dermal exposure. Total penetration of arsenic and nickel in the chemical mixture were significantly increased by 33% and 20% compared to arsenic and nickel alone, respectively. While more radioactivity penetrated skin with chemical treatment than metal alone, significantly less radioactivity was loosely adsorbed to skin and could be easily washed off from the skin surface with soap and water. The results of this study indicate that the potential health risk from dermal exposure to arsenic or nickel is enhanced if other chemicals are present.

Inhibitory effects of rosmarinic acid extracts on porcine pancreatic amylase in vitro.

PubMed

McCue, Patrick P; Shetty, Kalidas

2004-01-01

Porcine pancreatic alpha-amylase (PPA) was allowed to react with herbal extracts containing rosmarinic acid (RA) and purified RA. The derivatized enzyme-phytochemical mixtures obtained were characterized for residual amylase activity. These in vitro experiments showed that the amylase activity was inhibited in the presence of these phytochemicals. The extent of amylase inhibition correlated with increased concentration of RA. RA-containing oregano extracts yielded higher than expected amylase inhibition than similar amount of purified RA, suggesting that other phenolic compounds or phenolic synergies may contribute to additional amylase inhibitory activity. The significance of food-grade, plant-based amylase inhibitors for modulation of diabetes mellitus and other oxidation-linked diseases is hypothesized and discussed.

Process for solvent refining of coal using a denitrogenated and dephenolated solvent

DOEpatents

Garg, Diwakar; Givens, Edwin N.; Schweighardt, Frank K.

1984-01-01

A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

Factors Affecting the Extraction of Intact Ribonucleic Acid from Plant Tissues Containing Interfering Phenolic Compounds

PubMed Central

Newbury, H. John; Possingham, John V.

1977-01-01

Using conventional methods it is impossible to extract RNA as uncomplexed intact molecules from the leaves of grapevines (Vitis vinifera L.) and from a number of woody perennial species that contain high levels of reactive phenolic compounds. A procedure involving the use of high concentrations of the chaotropic agent sodium perchlorate prevents the binding of phenolic compounds to RNA during extraction. Analyses of the phenolics present in plant tissues used in these experiments indicate that there is a poor correlation between the total phenolic content and the complexing of RNA. However, qualitative analyses suggest that proanthocyanidins are involved in the tanning of RNA during conventional extractions. PMID:16660134

Surface-modified TiO2 powders with phenol derivatives: A comparative DFT and experimental study

NASA Astrophysics Data System (ADS)

Sredojević, Dušan N.; Kovač, Tijana; Džunuzović, Enis; Ðorđević, Vesna; Grgur, Branimir N.; Nedeljković, Jovan M.

2017-10-01

The charge transfer complex formation between TiO2 powder and variety of phenol derivatives (phenol, 4-nitrophenol, 4-bromophenol, 4-tert-butylphenol, hydroquinone) was achieved. The red-shift of optical absorption was observed upon surface modification of TiO2 powders with phenol derivatives. The influence of substituent functional groups in para position on the optical band gap and conduction band edge of inorganic/organic hybrids was studied using reflection spectroscopy and cyclic voltammetry. The experimental findings were supported by density functional theory calculations. The measured reflection spectra of surface-modified TiO2 powders with phenol derivatives were compared with calculated electronic excitation spectra of corresponding model systems.

Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values.

PubMed

Rasouli, Zolaikha; Ghavami, Raouf

2016-08-05

Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD=0.12], 0.67-23.19 [LOD=0.13] and 0.73-25.12 [LOD=0.15] μgmL(-1) for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigating the discrimination potential of linear and nonlinear spectral multivariate calibrations for analysis of phenolic compounds in their binary and ternary mixtures and calculation pKa values

NASA Astrophysics Data System (ADS)

Rasouli, Zolaikha; Ghavami, Raouf

2016-08-01

Vanillin (VA), vanillic acid (VAI) and syringaldehyde (SIA) are important food additives as flavor enhancers. The current study for the first time is devote to the application of partial least square (PLS-1), partial robust M-regression (PRM) and feed forward neural networks (FFNNs) as linear and nonlinear chemometric methods for the simultaneous detection of binary and ternary mixtures of VA, VAI and SIA using data extracted directly from UV-spectra with overlapped peaks of individual analytes. Under the optimum experimental conditions, for each compound a linear calibration was obtained in the concentration range of 0.61-20.99 [LOD = 0.12], 0.67-23.19 [LOD = 0.13] and 0.73-25.12 [LOD = 0.15] μg mL- 1 for VA, VAI and SIA, respectively. Four calibration sets of standard samples were designed by combination of a full and fractional factorial designs with the use of the seven and three levels for each factor for binary and ternary mixtures, respectively. The results of this study reveal that both the methods of PLS-1 and PRM are similar in terms of predict ability each binary mixtures. The resolution of ternary mixture has been accomplished by FFNNs. Multivariate curve resolution-alternating least squares (MCR-ALS) was applied for the description of spectra from the acid-base titration systems each individual compound, i.e. the resolution of the complex overlapping spectra as well as to interpret the extracted spectral and concentration profiles of any pure chemical species identified. Evolving factor analysis (EFA) and singular value decomposition (SVD) were used to distinguish the number of chemical species. Subsequently, their corresponding dissociation constants were derived. Finally, FFNNs has been used to detection active compounds in real and spiked water samples.

Infrared and Raman studies of hydrogen bonded complexes involving acetone, acetophenone and benzophenone—I. Thermodynamic constants and frequency shifts of the ν OH and ν CO stretching vibrations

NASA Astrophysics Data System (ADS)

Thijs, R.; Zeegers-Huyskens, Th.

The hydrogen bonded complexes between phenol derivatives and acetone ( I), acetophenone ( II) and benzophenone ( III) have been studied in carbon tetrachloride solution by i.r. spectroscopy. The formation constants, the enthalpies of complex formation, the Δν OH and Δν CO values have been determined. For a given phenol derivative, the thermodynamic constants and Δν OH are ordered according to I > II > III and the influence of a substituent implanted on the phenolic ring can be expressed by the Hammett relationship. The ϱ coefficients of the Hammett equation are related to the complexation enthalpies. The Badger—Bauer relation is valid for the three bases. The comparison with complexes involving other carbonyl bases allows to precise the influence of the substituent implanted on the carbonyl group. The Δν OH values obey the dual substituent parameter equation using σ I and σ +R; the ϱ I/ϱ R ratio is higher than one. The Δν CO values are shown to depend on the complexation enthalpy and on the delocalization effect of the substituents.

Synthesis, structures, and electroluminescent properties of scandium N,O-chelated complexes toward near-white organic light-emitting diodes.

PubMed

Katkova, Marina A; Balashova, Tatyana V; Ilichev, Vasilii A; Konev, Alexey N; Isachenkov, Nikolai A; Fukin, Georgy K; Ketkov, Sergey Yu; Bochkarev, Mikhail N

2010-06-07

Three members of a new class of electroluminescent, neutral, and monomeric scandium N,O-chelate complexes, namely, Sc(III)-tris-2-(2-benzoimidazol-2-yl)phenolate (1), Sc(III)-tris-2-(2-benzoxyazol-2-yl)phenolate (2), and Sc(III)-tris-2-(2-benzothiazol-2-yl)phenolate (3), have been prepared and X-ray characterized. DFT calculations have been performed. In contrast to the most frequently applied dual or multiple dopants in multilayer white OLED devices, all our simpler devices with the configuration of indium tin oxide/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine/neat scandium complex/Yb exhibit close to near-white emission with a blue hue (CIE(x,y) = 0.2147, 0.2379) in the case of 1, a cyan hue (0.2702, 0.3524) in the case of 2, and a yellowish hue (0.3468; 0.4284) in the case of 3.

Process monitored spectrophotometric titration coupled with chemometrics for simultaneous determination of mixtures of weak acids.

PubMed

Liao, Lifu; Yang, Jing; Yuan, Jintao

2007-05-15

A new spectrophotometric titration method coupled with chemometrics for the simultaneous determination of mixtures of weak acids has been developed. In this method, the titrant is a mixture of sodium hydroxide and an acid-base indicator, and the indicator is used to monitor the titration process. In a process of titration, both the added volume of titrant and the solution acidity at each titration point can be obtained simultaneously from an absorption spectrum by least square algorithm, and then the concentration of each component in the mixture can be obtained from the titration curves by principal component regression. The method only needs the information of absorbance spectra to obtain the analytical results, and is free of volumetric measurements. The analyses are independent of titration end point and do not need the accurate values of dissociation constants of the indicator and the acids. The method has been applied to the simultaneous determination of the mixtures of benzoic acid and salicylic acid, and the mixtures of phenol, o-chlorophenol and p-chlorophenol with satisfactory results.

Enhanced selective metal adsorption on optimised agroforestry waste mixtures.

PubMed

Rosales, Emilio; Ferreira, Laura; Sanromán, M Ángeles; Tavares, Teresa; Pazos, Marta

2015-04-01

The aim of this work is to ascertain the potentials of different agroforestry wastes to be used as biosorbents in the removal of a mixture of heavy metals. Fern (FE), rice husk (RI) and oak leaves (OA) presented the best removal percentages for Cu(II) and Ni(II), Mn(II) and Zn(II) and Cr(VI), respectively. The performance of a mixture of these three biosorbents was evaluated, and an improvement of 10% in the overall removal was obtained (19.25mg/g). The optimum mixture proportions were determined using simplex-centroid mixture design method (FE:OA:RI=50:13.7:36.3). The adsorption kinetics and isotherms of the optimised mixture were fit by the pseudo-first order kinetic model and Langmuir isotherm. The adsorption mechanism was studied, and the effects of the carboxylic, hydroxyl and phenolic groups on metal-biomass binding were demonstrated. Finally, the recoveries of the metals using biomass were investigated, and cationic metal recoveries of 100% were achieved when acidic solutions were used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distribution, fate and formation of non-extractable residues of a nonylphenol isomer in soil with special emphasis on soil derived organo-clay complexes.

PubMed

Riefer, Patrick; Klausmeyer, Timm; Schäffer, Andreas; Schwarzbauer, Jan; Schmidt, Burkhard

2011-01-01

Anthropogenic contaminants like nonylphenols (NP) are added to soil, for instance if sewage-sludge is used as fertilizer in agriculture. A commercial mixture of NP consists of more than 20 isomers. For our study, we used one of the predominate isomers of NP mixtures, 4-(3,5-dimethylhept-3-yl)phenol, as a representative compound. The aim was to investigate the fate and distribution of the isomer within soil and soil derived organo-clay complexes. Therefore, (14)C- and (13)C-labeled NP was added to soil samples and incubated up to 180 days. Mineralization was measured and soil samples were fractionated into sand, silt and clay; the clay fraction was further separated in humic acids, fulvic acids and humin. The organo-clay complexes pre-incubated for 90 or 180 days were re-incubated with fresh soil for 180 days, to study the potential of re-mobilization of incorporated residues. The predominate incorporation sites of the nonylphenol isomer in soil were the organo-clay complexes. After 180 days of incubation, 22 % of the applied (14)C was mineralized. The bioavailable, water extractable portion was low (9 % of applied (14)C) and remained constant during the entire incubation period, which could be explained by an incorporation/release equilibrium. Separation of organo-clay complexes, after extraction with solvents to release weakly incorporated, bioaccessible portions, showed that non-extractable residues (NER) were preferentially located in the humic acid fraction, which was regarded as an effect of the chemical composition of this fraction. Generally, 27 % of applied (14)C was incorporated into organo-clay complexes as NER, whereas 9 % of applied (14)C was bioaccessible after 180 days of incubation. The re-mobilization experiments showed on the one hand, a decrease of the bioavailability of the nonylphenol residues due to stronger incorporation, when the pre-incubation period was increased from 90 to 180 days. On the other hand, a shift of these residues from the clay fraction to other soil fractions was observed, implying a dynamic behavior of incorporated residues, which may result in bioaccessibility of the NER of nonylphenol.

Using Visible Spectrophotometers and pH Measurements to Study Speciation in a Guided-Inquiry Laboratory

ERIC Educational Resources Information Center

Otto, William H.; Larive, Cynthia K.; Mason, Susan L.; Robinson, Janet B.; Heppert Joseph A.; Ellis, James D.

2005-01-01

An experiment to perform a simple initial investigation that illustrates concepts of speciation and equilibrium, using the instrument and chemical resources in the laboratory is presented. The investigation showed that the presence of multiple chemical species in a reaction mixture (phenol red solution) reflects the acid and base conditions…

Novel nano-semiconductor film layer supported nano-Pd Complex Nanostructured Catalyst Pd/Ⓕ-MeOx/AC for High Efficient Selective Hydrogenation of Phenol to Cyclohexanone.

PubMed

Si, Jiaqi; Ouyang, Wenbing; Zhang, Yanji; Xu, Wentao; Zhou, Jicheng

2017-04-28

Supported metal as a type of heterogeneous catalysts are the most widely used in industrial processes. High dispersion of the metal particles of supported catalyst is a key factor in determining the performance of such catalysts. Here we report a novel catalyst Pd/Ⓕ-MeO x /AC with complex nanostructured, Pd nanoparticles supported on the platelike nano-semiconductor film/activated carbon, prepared by the photocatalytic reduction method, which exhibited high efficient catalytic performance for selective hydrogenation of phenol to cyclohexanone. Conversion of phenol achieved up to more than 99% with a lower mole ratio (0.5%) of active components Pd and phenol within 2 h at 70 °C. The synergistic effect of metal nanoparticles and nano-semiconductors support layer and the greatly increasing of contact interface of nano-metal-semiconductors may be responsible for the high efficiency. This work provides a clear demonstration that complex nanostructured catalysts with nano-metal and nano-semiconductor film layer supported on high specific surface AC can yield enhanced catalytic activity and can afford promising approach for developing new supported catalyst.

Removing tannins from medicinal plant extracts using an alkaline ethanol precipitation process: a case study of Danshen injection.

PubMed

Gong, Xingchu; Li, Yao; Qu, Haibin

2014-11-14

The alkaline ethanol precipitation process is investigated as an example of a technique for the removal of tannins extracted from Salviae miltiorrhizae Radix et Rhizoma for the manufacture of Danshen injection. More than 90% of the tannins can be removed. However, the recoveries of danshensu, rosmarinic acid, and salvianolic acid B were less than 60%. Total tannin removal increased as the refrigeration temperature decreased or the amount of NaOH solution added increased. Phenolic compound recoveries increased as refrigeration temperature increased or the amount of NaOH solution added decreased. When operated at a low refrigeration temperature, a relative high separation selectivity can be realized. Phenolic compound losses and tannin removal were mainly caused by precipitation. The formation of phenol salts, whose solubility is small in the mixture of ethanol and water used, is probably the reason for the precipitation. A model considering dissociation equilibrium and dissolution equilibrium was established. Satisfactory correlation results were obtained for phenolic compound recoveries and total tannin removal. Two important parameters in the model, which are the water content and pH value of alkaline supernatant, are suggested to be monitored and controlled to obtain high batch-to-batch consistency.

Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds

PubMed Central

Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md. Rakibul

2016-01-01

A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075–10 µM and 10–55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days. PMID:27367738

Phylogenetic and functional diversity of metagenomic libraries of phenol degrading sludge from petroleum refinery wastewater treatment system

PubMed Central

2012-01-01

In petrochemical refinery wastewater treatment plants (WWTP), different concentrations of pollutant compounds are received daily in the influent stream, including significant amounts of phenolic compounds, creating propitious conditions for the development of particular microorganisms that can rapidly adapt to such environment. In the present work, the microbial sludge from a refinery WWTP was enriched for phenol, cloned into fosmid vectors and pyrosequenced. The fosmid libraries yielded 13,200 clones and a comprehensive bioinformatic analysis of the sequence data set revealed a complex and diverse bacterial community in the phenol degrading sludge. The phylogenetic analyses using MEGAN in combination with RDP classifier showed a massive predominance of Proteobacteria, represented mostly by the genera Diaphorobacter, Pseudomonas, Thauera and Comamonas. The functional classification of phenol degrading sludge sequence data set generated by MG-RAST showed the wide metabolic diversity of the microbial sludge, with a high percentage of genes involved in the aerobic and anaerobic degradation of phenol and derivatives. In addition, genes related to the metabolism of many other organic and xenobiotic compounds, such as toluene, biphenyl, naphthalene and benzoate, were found. Results gathered herein demonstrated that the phenol degrading sludge has complex phylogenetic and functional diversities, showing the potential of such community to degrade several pollutant compounds. This microbiota is likely to represent a rich resource of versatile and unknown enzymes which may be exploited for biotechnological processes such as bioremediation. PMID:22452812

Effect of solvents extraction on total phenolics and antioxidant activity of extracts from flaxseed (Linum usitatissimum L.).

PubMed

Anwar, Farooq; Przybylski, Roman

2012-01-01

Plant origin food ingredients are the main source of very potent antioxidants. Tocopherols, the main oilseeds natural antioxidants are very potent and when implemented into cell membranes are able to scavenge large number of free radicals. Among plant antioxidants are mainly phenolics, large and diversified group of chemical compounds with different radical scavenging potential. Defatted flaxseed meals were extracted with pure alcohols and its mixture with water. Acquired extracts were analysed for the content of phenolics and flavonoids using colorimetric procedures. Antioxidative capacity was assessed by utilizing: DPPH stable free radicals; inhibition of linoleic acid oxidation and reducing power of components. Investigation was conducted on two different batches of flaxseed, assessing antioxidant capacity of compounds extracted with different polarity solvents and extracts were tested for antioxidant activity with different methods. The highest yield of extraction was achieved with 80% methanol but the extract did not contain the highest amount of phenolics and flavonoids. When 80% ethanol was used for extraction the highest amount of flavonoids was detected and also the best antioxidant capacity. The results clearly showed that utilization of polar solvent enable extraction of significant amounts of phenolics and flavonoids. Those components were the most potent antioxidants present in those extracts. Content of these compounds correlated well with results from applied methods for antioxidant assessment.

Hydrogen sulfide oxidation by a microbial consortium in a recirculation reactor system: sulfur formation under oxygen limitation and removal of phenols.

PubMed

Alcantara, Sergio; Velasco, Antonio; Muñoz, Ana; Cid, Juan; Revah, Sergio; Razo-Flores, Elías

2004-02-01

Wastewater from petroleum refining may contain a number of undesirable contaminants including sulfides, phenolic compounds, and ammonia. The concentrations of these compounds must be reduced to acceptable levels before discharge. Sulfur formation and the effect of selected phenolic compounds on the sulfide oxidation were studied in autotrophic aerobic cultures. A recirculation reactor system was implemented to improve the elemental sulfur recovery. The relation between oxygen and sulfide was determined calculating the O2/S2- loading rates (Q(O2)/Q(S)2- = Rmt), which adequately defined the operation conditions to control the sulfide oxidation. Sulfur-producing steady states were achieved at Rmt ranging from 0.5 to 1.5. The maximum sulfur formation occurred at Rmt of 0.5 where 85% of the total sulfur added to the reactor as sulfide was transformed to elemental sulfur and 90% of it was recovered from the bottom of the reactor. Sulfide was completely oxidized to sulfate (Rmt of 2) in a stirred tank reactor, even when a mixture of phenolic compounds was present in the medium. Microcosm experiments showed that carbon dioxide production increased in the presence of the phenols, suggesting that these compounds were oxidized and that they may have been used as carbon and energy source by heterotrophic microorganisms present in the consortium.

The Mechanism of Melanocytes-Specific Cytotoxicity Induced by Phenol Compounds Having a Prooxidant Effect, relating to the Appearance of Leukoderma

PubMed Central

Ito, Shinobu; Kanazawa, Hideko; Masaki, Hitoshi

2015-01-01

Specific phenol compounds including rhododendrol (RD), a skin-brightening ingredient in cosmetics, are reported to induce leukoderma, inducing a social problem, and the elucidation of mechanism of leukoderma is strongly demanded. This study investigated the relationship among the cytotoxicities of six phenol compounds on B16F10 melanoma cells and HaCaT keratinocytes and generated reactive oxygen species (ROS). As a result, the cytotoxicity of RD on B16F10 cells was higher than that on HaCaT cells, and RD significantly increased intracellular ROS and hydrogen peroxide (H2O2) levels in B16F10 cells. Furthermore, although raspberry ketone (RK), RD derivative, also increased intracellular ROS in B16F10 cells, increase in ROS was suppressed by disodium dihydrogen ethylenediaminetetraacetate dehydrate (EDTA). The amounts of increased ROS with RK in HaCaT cells without melanocyte were further increased by tyrosinase. Therefore, tyrosinase, a metalloprotein having copper, was speculated to be one of causative agents allowing phenol compounds to work as a prooxidant. Hydroxyl radical was generated by adding a mixture of tyrosinase and H2O2 to RD, and the amount of the radical was further increased by UVB, indicating that RD cytotoxicity was caused by intracellularly increased ROS, which possibly related to phenol induced prooxidants. PMID:25861631

Effect of virgin olive oil and thyme phenolic compounds on blood lipid profile: implications of human gut microbiota.

PubMed

Martín-Peláez, Sandra; Mosele, Juana Ines; Pizarro, Neus; Farràs, Marta; de la Torre, Rafael; Subirana, Isaac; Pérez-Cano, Francisco José; Castañer, Olga; Solà, Rosa; Fernandez-Castillejo, Sara; Heredia, Saray; Farré, Magí; Motilva, María José; Fitó, Montserrat

2017-02-01

To investigate the effect of virgin olive oil phenolic compounds (PC) alone or in combination with thyme PC on blood lipid profile from hypercholesterolemic humans, and whether the changes generated are related with changes in gut microbiota populations and activities. A randomized, controlled, double-blind, crossover human trial (n = 12) was carried out. Participants ingested 25 mL/day for 3 weeks, preceded by 2-week washout periods, three raw virgin olive oils differing in the concentration and origin of PC: (1) a virgin olive oil (OO) naturally containing 80 mg PC/kg, (VOO), (2) a PC-enriched virgin olive oil containing 500 mg PC/kg, from OO (FVOO), and (3) a PC-enriched virgin olive oil containing a mixture of 500 mg PC/kg from OO and thyme, 1:1 (FVOOT). Blood lipid values and faecal quantitative changes in microbial populations, short chain fatty acids, cholesterol microbial metabolites, bile acids, and phenolic metabolites were analysed. FVOOT decreased seric ox-LDL concentrations compared with pre-FVOOT, and increased numbers of bifidobacteria and the levels of the phenolic metabolite protocatechuic acid compared to VOO (P < 0.05). FVOO did not lead to changes in blood lipid profile nor quantitative changes in the microbial populations analysed, but increased the coprostanone compared to FVOOT (P < 0.05), and the levels of the faecal hydroxytyrosol and dihydroxyphenylacetic acids, compared with pre-intervention values and to VOO, respectively (P < 0.05). The ingestion of a PC-enriched virgin olive oil, containing a mixture of olive oil and thyme PC for 3 weeks, decreases blood ox-LDL in hypercholesterolemic humans. This cardio-protective effect could be mediated by the increases in populations of bifidobacteria together with increases in PC microbial metabolites with antioxidant activities.

Biotransformation of furanic and phenolic compounds with hydrogen gas production in a microbial electrolysis cell

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2015-10-27

In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H 2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H 2 production, as well as the anode microbial community structure were investigated. The five compoundsmore » were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H 2 yield varied from 0.26 to 0.42 g H 2-COD/g COD removed in the anode, and the bioanode volume-normalized H 2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H 2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H 2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H 2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

Biotransformation of Furanic and Phenolic Compounds with Hydrogen Gas Production in a Microbial Electrolysis Cell.

PubMed

Zeng, Xiaofei; Borole, Abhijeet P; Pavlostathis, Spyros G

2015-11-17

Furanic and phenolic compounds are problematic byproducts resulting from the breakdown of lignocellulosic biomass during biofuel production. The capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the substrate in the bioanode was assessed. The rate and extent of biotransformation of the five compounds and efficiency of H2 production, as well as the structure of the anode microbial community, were investigated. The five compounds were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode Coulombic efficiency was 44-69%, which is comparable to that of wastewater-fed MECs. The H2 yield varied from 0.26 to 0.42 g H2-COD/g COD removed in the anode, and the bioanode volume-normalized H2 production rate was 0.07-0.1 L/L-d. The biotransformation of the five compounds took place via fermentation followed by exoelectrogenesis. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H2 production were inhibited at an initial substrate concentration of 1200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The MEC H2 production demonstrated in this study is an alternative to the currently used process of reforming natural gas to supply H2 needed to upgrade bio-oils to stable hydrocarbon fuels.

One-electron oxidation of electronically diverse manganese(III) and nickel(II) salen complexes: transition from localized to delocalized mixed-valence ligand radicals.

PubMed

Kurahashi, Takuya; Fujii, Hiroshi

2011-06-01

Ligand radicals from salen complexes are unique mixed-valence compounds in which a phenoxyl radical is electronically linked to a remote phenolate via a neighboring redox-active metal ion, providing an opportunity to study electron transfer from a phenolate to a phenoxyl radical mediated by a redox-active metal ion as a bridge. We herein synthesize one-electron-oxidized products from electronically diverse manganese(III) salen complexes in which the locus of oxidation is shown to be ligand-centered, not metal-centered, affording manganese(III)-phenoxyl radical species. The key point in the present study is an unambiguous assignment of intervalence charge transfer bands by using nonsymmetrical salen complexes, which enables us to obtain otherwise inaccessible insight into the mixed-valence property. A d(4) high-spin manganese(III) ion forms a Robin-Day class II mixed-valence system, in which electron transfer is occurring between the localized phenoxyl radical and the phenolate. This is in clear contrast to a d(8) low-spin nickel(II) ion with the same salen ligand, which induces a delocalized radical (Robin-Day class III) over the two phenolate rings, as previously reported by others. The present findings point to a fascinating possibility that electron transfer could be drastically modulated by exchanging the metal ion that bridges the two redox centers. © 2011 American Chemical Society

Evaluation of protective effect of different dietary fibers on polyphenolic profile stability of maqui berry (Aristotelia chilensis (Molina) Stuntz) during in vitro gastrointestinal digestion.

PubMed

Viuda-Martos, Manuel; Lucas-Gonzalez, Raquel; Ballester-Costa, Carmen; Pérez-Álvarez, José A; Muñoz, Loreto A; Fernández-López, Juana

2018-01-24

The aim of this work was to determine the protective effect of different dietary fibers on (i) the recovery and bioaccessibility indexes, and (ii) the stability of polyphenolic compounds (phenolic acids, flavonoids and anthocyanins) of maqui berry powder subjected to in vitro gastrointestinal digestion (GID). The extracts obtained in each phase (oral, gastric and intestinal) of GID were used to analyze the stability of polyphenolic compounds by HPLC, and the bioaccessibility of these compounds was also determined. At the end of the GID process, the mixture of maqui berry with the different fibers increased the bioaccessibility index of the phenolic and flavonoid compounds in all cases. The results obtained suggest that the anthocyanins and phenolic acids and flavonoid compounds present in maqui are stabilized through dietary fiber interactions, which might provide sufficient levels for absorption during gastrointestinal digestion. The gums sodium carboxymethyl cellulose, xanthan gum and guar gum provided the best protective effect.

Evaluation of antioxidant capacity of Chinese five-spice ingredients.

PubMed

Bi, Xinyan; Soong, Yean Yean; Lim, Siang Wee; Henry, Christiani Jeyakumar

2015-05-01

Phenolic compounds in spices were reportedly found to possess high antioxidant capacities (AOCs), which may prevent or reduce risk of human diseases such as cardiovascular disease, cancer and diabetes. The potential AOC of Chinese five-spice powder (consist of Szechuan pepper, fennel seed, cinnamon, star anise and clove) with varying proportion of individual spice ingredients was investigated through four standard methods. Our results suggest that clove is the major contributor to the AOC of the five-spice powder whereas the other four ingredients contribute to the flavour. For example, the total phenolic content as well as ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values increased linearly with the clove percentage in five-spice powder. This observation opens the door to use clove in other spice mixtures to increase their AOC and flavour. Moreover, linear relationships were also observed between AOC and the total phenolic content of the 32 tested spice samples.

Use of different spices as potential natural antioxidant additives on cooked beans (Phaseolus vulgaris). Increase of DPPH radical scavenging activity and total phenolic content.

PubMed

Pereira, Marina Pelincer; Tavano, Olga Luisa

2014-12-01

Herbs and spices, excellent sources of phenolic compounds, can be considered potential antioxidant additives. The use of spices must strike a balance between their potential antioxidant capabilities during preparation and the flavor acceptance, in order to avoid rejection of the food. The aimed of this study is to evaluate the influence of different spices and their concentrations on cooked common beans, focusing its potential as antioxidant additives. Onion, parsley, spring onion, laurel and coriander increased the antioxidant activity of preparation when used at 7.96 g of onion, 1.06 g parsley, 3.43 g spring onion, 0.25 g laurel (dry leaves), and 0.43 g coriander/100 g of cooked beans. Besides, these spices concentrations enhance total phenolics and alter the mixture protein digestibility minimally. For garlic samples it was not possible to establish a concentration that increases the antioxidant activity of cooked beans.

Lichenysin, a cyclooctapeptide occurring in Chinese liquor jiannanchun reduced the headspace concentration of phenolic off-flavors via hydrogen-bond interactions.

PubMed

Zhang, Rong; Wu, Qun; Xu, Yan

2014-08-20

Nonvolatile compounds play important roles in the quality of alcoholic beverages. In our previous work, a type of cyclooctapeptide lichenysin was newly identified in Chinese strong-aroma type liquor. In this work, it was found that lichenysin could selectively affect aroma volatility in strong-aroma type (Jiannanchun) liquor. Interaction of lichenysin and volatile phenolic compounds (off-odors in strong-aroma type liquor) was characterized using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). HS-SPME results indicated that lichenysin very efficiently suppressed the volatility of phenolic compounds by 36-48% (P < 0.05). Thermodynamic analysis showed that the binding process was mainly mediated by hydrogen bonding. Furthermore, the mixture of lichenysin and 4-ethylguaiacol revealed intermolecular cross peaks between the aH (Val) of lichenysin and the 1H of 4-ethylguaiacol, by using nuclear Overhauser effect spectroscopy. This study will help to further understand the interaction mechanisms between flavor and nonvolatile matrix components in Chinese liquors.

Understanding the Impact of Charcoal Inputs to Soils and Sediments on Conventional Geochemical Markers

NASA Astrophysics Data System (ADS)

Kuo, L.; Louchouarn, P.; Herbert, B.

2008-12-01

Chars/charcoals are solid combustion residues derived from biomass burning. They represent one of the major classes in the pyrogenic organic residues, the so-called black carbon (BC), and have highly heterogeneous nature due to the highly variable combustion conditions during biomass burning. More and more attention has been given to characterize and quantify the inputs of charcoals to different environmental compartments since they also share the common features of BC, such as recalcitrant nature and strong sorption capacity on hydrophobic organic pollutants. Moreover, such inputs also imply the thermal alteration of terrestrial organic matter, as well as corresponding biomarkers such as lignin. Lignin is considered to be among the best-preserved components of vascular plants after deposition, due to its relative stability on biodegradation. This macropolymer is an important contributor to soil organic matter (SOM) and its presence in aquatic environments helps trace the input of terrigenous organic matter to such systems. The yields and specific ratios of lignin oxidation products (LOP) from alkaline cupric oxide (CuO) oxidation method have been extensively used to identify the structure of plant lignin and estimate inputs of plant carbon to soils and aquatic systems, as well as evaluate the diagenetic status of lignin. Although the fate of lignin under microbiological and photochemical degradation pathways have been thoroughly addressed in the literature, studies assessing the impact of thermal degradation on lignin structure and signature are scarce. In the present study, we used three suites of lab-made chars (honey mesquite, cordgrass, and loblolly pine) to study the impact of combustion on lignin and their commonly used parameters. Our results show that combustion can greatly decrease the yields of the eight major lignin phenols (vanillyl, syringyl, and cinnamyl phenols) with no lignin phenols detected in any synthetic char produced at ≥ 400°C. With increasing combustion temperature, internal phenol ratios (S/V and C/V) show a two-stage change with an initial increase at low temperatures followed by marked and rapid decreases when temperatures reach 200- 250°C. The acid/aldehyde ratios of vanillyl phenols ((Ad/Al)v) and syringyl phenols ((Ad/Al)s) all increase with increasing combustion temperature and duration and reach a maximum values at 300- 350°C, regardless plant species. The highly elevated acid/aldehyde ratios reached in some cases exceed the reported values of humic and fulvic acids extracted from soils and sediments. We applied these empirical data in mixing models to estimate the potential effects of charcoal inputs on the observed lignin signatures in environmental mixtures. The shifts in lignin signatures are strongly influenced both by the characteristics of the charcoal incorporated and the proportion of charcoal in the mixture. We validated our observations with two sets of environmental samples, including soils from control burning sites, and a sediment core from a wetland with evidence of charcoal inputs, showing that the presences of charcoals do alter the observed lignin signals in these samples. Such a thermal "interference" on lignin parameters should thus be considered in environmental mixtures with recognized char input.

Dichlorido-1κCl,3κCl-bis­{μ-2,2′-[pro­pane-1,3-diylbis(imino­methyl­ene)]di­phenol­ato}-1:2κ6 O,N,N′,O′:O,O′;2:3κ6 O,O′:O,N,N′,O′-tricopper(II)

PubMed Central

Ateş, Bürke Meltem; Ercan, Filiz; Svoboda, Ingrid; Fuess, Hartmut; Atakol, Orhan

2008-01-01

The title linear trinuclear copper(II) complex, [Cu3(C17H20N2O2)2Cl2], was obtained from N,N′-bis­(2-hydroxy­benz­yl)-1,3-propane­diamine and CuCl2. The overall charge of the three Cu2+ ions is balanced by four deprotonated phenol groups and two Cl− ligands. The complex is centrosymmetric with the central Cu2+ occupying a special position (). This Cu2+ ion is coordinated by the four phenolate O atoms in a square-planar fashion. The second Cu2+ occupies a general position in a square-pyramidal fashion. Two phenolate O atoms and two amine N form the basal plane, with Cl− ligands occupying the fifth coordination site. PMID:21201868

Methanol Extracts of 28 Hieracium Species from the Balkan Peninsula - Comparative LC-MS Analysis, Chemosystematic Evaluation of their Flavonoid and Phenolic Acid Profiles and Antioxidant Potentials.

PubMed

Milutinović, Violeta; Niketić, Marjan; Ušjak, Ljuboš; Nikolić, Dejan; Krunić, Aleksej; Zidorn, Christian; Petrović, Silvana

2018-01-01

Hieracium s. str. represents one of the largest and most complex genera of flowering plants. As molecular genetics seems unlikely to disentangle intricate relationships within this reticulate species complex, analysis of flavonoids and phenolic acids, known as good chemosystematic markers, promise to be more reliable. Data about pharmacological activity of Hieracium species are scarce. Evaluation of the chemosystematic significance of flavonoids and phenolic acids of methanol extracts of aerial flowering parts of 28 Hieracium species from the Balkans. Additionally, investigation of antioxidant potentials of the extracts. Comparative qualitative and quantitative analysis of flavonoids and phenolic acids was performed by LC-MS. Multivariate statistical data analysis included non-metric multidimensional scaling (nMDS), unweighted pair-group arithmetic averages (UPGMA) and principal component analysis (PCA). Antioxidant activity was evaluated using three colorimetric tests. Dominant phenolics in almost all species were luteolin type flavonoids, followed by phenolic acids. Although the investigated Hieracium species share many compounds, the current classification of the genus was supported by nMDS and UPGMA analyses with a good resolution to the group level. Hieracium naegelianum was clearly separated from the other investigated species. Spatial and ecological distances of the samples were likely to influence unexpected differentiation of some groups within H. sect. Pannosa. The vast majority of dominant compounds significantly contributed to differences between taxa. The antioxidant potential of the extracts was satisfactory and in accordance with their phenolics composition. Comparative LC-MS analysis demonstrated that flavonoids and phenolic acids are good indicators of chemosystematic relationships within Hieracium, particularly between non-hybrid species and groups from the same location. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Using the DFT-D method to describe dispersion interactions in systems of weakly-bonded Xe-aromatic molecules

NASA Astrophysics Data System (ADS)

Andriichenko, N. N.; Ermilov, A. Yu.

2013-08-01

The optimum version of the DFT-D class of methods (BHHLYP-D2, 6-31G*) is chosen to describe binding in a Xe-phenol system with the aim of subsequent KM/MM calculations for complex Xe-containing protein systems. It is shown that the stability of the Xe-phenol system is due to weak dispersion interactions not described in conventional approaches using the density functional. The MP2 approach using the (aug)-cc-pVTZ basis and Stuttgart pseudopotential, which yield the best reproduction of the characteristics of a Xe2 xenon dimer, is chosen as the reference standard. It is noted that the 2010 DFT-D3 methods underestimate the binding energy by a factor of nearly three, while DFT methods without dispersion corrections do not reproduce the stability of Xe2 and Xe-phenol systems. It is found that in the best version of calculations, BHHLYP-D2, the binding energy in Xe-phenol complex is estimated to be 2.7 kcal/mol versus the 3.1 kcal/mol found using the comparative approach. It is concluded that BHHLYP-D2 adequately reproduces the difference between the two conformers of the Xe-phenol complex and trend toward an increase in binding energy in the series of aromatic amino acids (phenylalanine, tyrosine, and tryptophan). DFT-D can also indicate the existence of excess conformers that are missing in systems according to more precise descriptions (MP2/(aug)-cc-pVTZ).

Biodegradation of phenolic compounds by Basidiomycota and its phenol oxidases: A review.

PubMed

Martínková, L; Kotik, M; Marková, E; Homolka, L

2016-04-01

The phylum Basidiomycota include organisms with enormous bioremediation potential. A variety of processes were proposed at the lab scale for using these fungi and their phenol oxidases in the degradation of phenolics. Here we present a survey of this topic using literature published mostly over the last 10 years. First, the sources of the enzymes are summarized. The laccase and tyrosinase were mainly from Trametes versicolor and Agaricus bisporus, respectively. Recently, however, new promising wild-type producers of the enzymes have emerged and a number of recombinant strains were also constructed, based mainly on yeasts or Aspergillus strains as hosts. The next part of the study summarizes the enzyme and whole-cell applications for the degradation of phenols, polyphenols, cresols, alkylphenols, naphthols, bisphenols and halogenated (bis)phenols in model mixtures or real wastewaters from the food, paper and coal industries, or municipal and hospital sewage. The enzymes were applied as free (crude or purified) enzymes or as enzymes immobilized in various supports or CLEAs, and optionally recycled or used in continuous mode. Alternatively, growing cultures or harvested mycelia were used instead. The products, which were characterized as quinones and their polymers in some cases, could be eliminated by filtration, flocculation or adsorption onto chitosan. The purity of a treated wastewater was monitored using a sensitive aquatic organism. It is concluded that low-cost sources of these enzymes should be searched for and the benefits of enzymatic, biological and physico-chemical methods could be combined to make the processes fit for industrial use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extraction of phenol using trialkylphosphine oxides (Cyanex 923) in kerosene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Urtiaga, A.M.; Ortiz, I.

1997-04-01

A group of extractants based on phosphine oxides have been reported as an alternative to conventional polar solvents for phenol-liquid-liquid extraction. Among phosphoryl extractants, Cyanex 923 (a mixture of four trialkylphosphine oxides, alkyl = normal, C{sub 6}, C{sub 8}) has proved to combine high extraction efficiency and low water solubility, obviating the necessity of removing the solvent from the aqueous raffinate, a need associated with the use of methyl isobutyl ketone and isopropyl ether, the solvents most widely employed for this application. Phosphoryl extractants are solvating extractants, and are known to form relatively strong and reversible hydrogen bonds with phenols.more » The fact that most of these systems show a strong nonideality in the organic phase makes a general theoretical treatment of the equilibria almost impossible, leading to the necessity of obtaining a large number of data in order to describe the equilibria for design purposes. In this work the effect of the concentration of phenol in the aqueous phase on the partition coefficient for phenol in Cyanex 923-kerosene/water systems is investigated at six different concentrations of the extractant in the organic phase: 1, 5, 10, 20, 50, and 70% v/v of Cyanex 923-kerosene/water systems is investigated at six different concentrations of the extractant in the organic phase: 1, 5, 10, 20, 50, and 70% v/v of Cyanex 923 in kerosene. The initial concentrations of phenol in the aqueous phase were in the 1000 mg/L < C{sub PhOH} < 50,000 mg/L range.« less

Phenolic profiles and their contribution to the antioxidant activity of selected chickpea genotypes from Mexico and ICRISAT collections.

PubMed

Quintero-Soto, Maria F; Saracho-Peña, Ana G; Chavez-Ontiveros, Jeanett; Garzon-Tiznado, Jose A; Pineda-Hidalgo, Karen V; Delgado-Vargas, Francisco; Lopez-Valenzuela, Jose A

2018-06-01

Chickpea (Cicer arietinum L.) genotypes, nine kabuli from Mexico and 9 desi from other countries, were investigated for their phenolic profiles and antioxidant activity (AA). Phenolics in methanol extracts (ME) were analyzed by ultra-performance liquid chromatography coupled to diode array detection and mass spectrometry (UPLC-DAD-MS), whereas the AA was measured as Trolox equivalents (TE) by ABTS, DPPH and FRAP methods. Twenty phenolic compounds were identified in the ME and their levels showed a great variability among the chickpea genotypes. Phenolic acids and flavonoids were the most abundant compounds in kabuli and desi genotypes, respectively. The AA values (μmol TE/ 100 g dw) by ABTS (278-2417), DPPH (52-1650), and FRAP (41-1181) were mainly associated with the content of sinapic acid hexoside, gallic acid, myricetin, quercetin, catechin, and isorhamnetin, suggesting they are the main compounds responsible for the AA. The sum of the AA obtained for standards of these compounds evaluated at the concentration found in the extracts accounted for 34.3, 69.8, and 47.0% of the AA in the extract by ABTS, DPPH, and FRAP, respectively. In the AA by DPPH, most of the mixtures of these compounds resulted in synergistic interactions. Three desi genotypes with black seeds (ICC 4418, ICC 6306, and ICC 3761) showed the highest AA and flavonoids content, whereas the most promising kabuli genotypes were Surutato 77, Bco. Sin. 92, and Blanoro that showed the highest values of phenolic acids. These genotypes represent good sources of antioxidants for the improvement of nutraceutical properties in chickpea.

A simple and rapid electrophoretic method to characterize simple phenols, lignans, complex phenols, phenolic acids, and flavonoids in extra-virgin olive oil.

PubMed

Carrasco-Pancorbo, Alegria; Gómez-Caravaca, Ana Maria; Cerretani, Lorenzo; Bendini, Alessandra; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2006-09-01

We have devised a simple and rapid capillary electrophoretic method which provides the analyst with a useful tool for the characterization of the polyphenolic fraction of extra-virgin olive oil. This method that uses a capillary with 50 microm id and a total length of 47 cm (40 cm to the detector) with a detection window of 100 x 200 microm, and a buffer solution containing 45 mM of sodium tetraborate pH 9.3 offers valuable information about all the families of compounds present in the polar fraction of the olive oil. The detection was carried out by UV absorption at 200, 240, 280, and 330 nm in order to facilitate the identification of the compounds. Concretely, the method permits the identification of simple phenols, lignans, complex phenols (isomeric forms of secoiridoids), phenolic acids, and flavonoids in the SPE-Diol extracts from extra-virgin olive oil in a short time (less than 10 min) and provides a satisfactory resolution. Peak identification was done by comparing both migration time and spectral data obtained from olive oil samples and standards (commercial or isolated (by HPLC-MS) standards), with spiked methanol-water extracts of olive oil with HPLC-collected compounds and commercially available standards at several concentration levels, studying the information of the electropherograms obtained at several wavelengths and also using the information previously reported.

Aqueous benzene-diols react with an organic triplet excited state and hydroxyl radical to form secondary organic aerosol.

PubMed

Smith, Jeremy D; Kinney, Haley; Anastasio, Cort

2015-04-21

Chemical processing in atmospheric aqueous phases, such as cloud and fog drops, can play a significant role in the production and evolution of secondary organic aerosol (SOA). In this work we examine aqueous SOA production via the oxidation of benzene-diols (dihydroxy-benzenes) by the triplet excited state of 3,4-dimethoxybenzaldehyde, (3)DMB*, and by hydroxyl radical, ˙OH. Reactions of the three benzene-diols (catechol (CAT), resorcinol (RES) and hydroquinone (HQ)) with (3)DMB* or ˙OH proceed rapidly, with rate constants near diffusion-controlled values. The two oxidants exhibit different behaviors with pH, with rate constants for (3)DMB* increasing as pH decreases from pH 5 to 2, while rate constants with ˙OH decrease in more acidic solutions. Mass yields of SOA were near 100% for all three benzene-diols with both oxidants. We also examined the reactivity of atmospherically relevant mixtures of phenols and benzene-diols in the presence of (3)DMB*. We find that the kinetics of phenol and benzene-diol loss, and the production of SOA mass, in mixtures are generally consistent with rate constants determined in experiments containing a single phenol or benzene-diol. Combining our aqueous kinetic and SOA mass yield data with previously published gas-phase data, we estimate a total SOA production rate from benzene-diol oxidation in a foggy area with significant wood combustion to be nearly 0.6 μg mair(-3) h(-1), with approximately half from the aqueous oxidation of resorcinol and hydroquinone, and half from the gas-phase oxidation of catechol.

Optimizing the orosensory properties of model functional beverages: the influence of novel sweeteners, odorants, bitter blockers, and their mixtures on (+)-catechin.

PubMed

Gaudette, Nicole J; Pickering, Gary J

2012-06-01

The use of flavor-modifying strategies are important to improving the sensory profile of some excessively bitter and astringent functional ingredients, such as (+)-catechin (CAT). Two bitter blockers (ß-cyclodextrin [CYCLO], homoeriodictyol sodium salt [HED]), two sweeteners (sucrose [SUC], rebaudioside A [REB]), and two odorants (vanillin [VAN], black tea aroma [TEA]) were assessed for their efficacy at modifying the bitterness and astringency of CAT in model aqueous solutions. The intensity of oral sensations elicited by CAT was determined in duplicate in binary, ternary, and quaternary mixtures of these stimuli by a trained panel (n = 15) using a 15 cm visual analogue scale. Overall, bitterness and astringency were most effectively reduced by ternary solutions containing CYCLO + REB or CYCLO + SUC (68%, 60%, and 45%, 43% for bitterness and astringency, respectively). Odorants were not effective at modifying the bitterness or astringency of CAT. We conclude that the use of select bitter blockers and sweeteners may be of value in optimizing the flavor and acceptance of functional food and beverages fortified with phenolic compounds. (+)-Catechin is a bitter-tasting plant-derived health-promoting phenolic compound of interest to functional food and beverage manufacturers. We investigated the efficacy of bitter blockers, plant-based sweeteners, and odorants in decreasing the bitterness and astringency elicited by (+)-catechin. Some of these additives, both alone and in combination, reduced bitterness and astringency, and may therefore assist in optimizing the flavor and consumer acceptance of some phenolic-based functional foods and beverages. © 2012 Institute of Food Technologists®

Prevention of renal dysfunction by nutraceuticals prepared from oil rich plant foods

PubMed Central

Al-Okbi, Sahar Y.; Mohamed, Doha A.; Hamed, Thanaa E.; Esmail, Reham SH.; Donya, Souria M.

2014-01-01

Objective To investigate the protective effect of extracts prepared from avocado, walnut, flaxseed and Eruca sativa seeds in a rat model of kidney dysfunction induced by intraperitoneal cisplatin. Methods Ethanol and petroleum ether extracts mixture was prepared from each plant. Six groups of rats were conducted; control healthy, cisplatin group and four test groups where rats were given daily oral dose of each extract mixture before cisplatin injection. Different biochemical and cytogenetic parameters and kidney histopathology were determined. Acute toxicity was tested for the nutraceuticals. Total phenolic contents, fatty acids (FA) and unsaponifiable matter were assessed in the extracts. Results Walnut ethanol extract showed the highest content of total phenolic. FA analysis revealed that all the studied plants were rich in unsaturated FA. Gas-liquid chromatographic investigation of the unsaponifiable matter showed the presence of campesterol, stigmasterol and β-sitosterol in all the studied plants. Cisplatin treatment induced significant increase in plasma urea, creatinine and malondialdehyde along with significant reduction of plasma albumin, total protein, catalase and total antioxidant as well as reduction in creatinine clearance. Histopathological examination proved the induction of kidney dysfunction. Some sorts of chromosomal aberration and sperm-shape abnormalities were noticed after cisplatin treatment. Administration of extracts mixtures produced improvements in biochemical, histopathological and cytogenetic parameters. Conclusions Administration of the studied nutraceuticals proved to possess protective role against cisplatin-induced nephrotoxicity, chromosomal aberration and abnormal sperms. All studied nutraceuticals showed complete safety. PMID:25183331

The efficiency of different phenol-degrading bacteria and activated sludges in detoxification of phenolic leachates.

PubMed

Kahru, A; Reiman, R; Rätsep, A

1998-07-01

Phenolic composition, toxicity and biodegradability of three different phenolic leachates/samples was studied. Samples A and C were the leachates from the oil-shale industry spent shale dumps at Kohtla-Järve, Estonia. Sample B was a laboratory-prepared synthetic mixture of 7 phenolic compounds mimmicking the phenolic composition of the leachate A. Toxicity of these 3 samples was analyzed using two photobacterial test (BioTox and Microtox), Daphnia test (DAPHTOXKIT F pulex) and rotifiers' test (ROTOXKIT F). All the LC50 values were in the range of 1-10%, leachate A being the most toxic. The growth and detoxifying potential (toxicity of the growth medium was measured using photobacterial tests) of 3 different phenol-utilizing bacteria and acclimated activated sludges was studied in shake-flask cultures. 30% leachate A (altogether 0.6 mM total phenolic compounds) was too toxic to rhodococci and they did not grow. Cell number of Kurthia sp. and Pseudomonas sp. in 30% leachate A increased by 2 orders of magnitude but despite of the growth of bacteria the toxicity of the leachate did not decrease even by 7 weeks of cultivation. However, if the activated sludge was used instead of pure bacterial cultures the toxicity of the 30% leachate A was eliminated already after 3 days of incubation. 30% samples B and C were detoxified by activated sludge even more rapidly, within 2 days. As the biodegradable part of samples A and B should be identical, the detoxification of leachate A compared to that of sample B was most probably inhibited by inorganic (e.g. sulphuric) compounds present in the leachate A. Also, the presence of toxic recalcitrant organic compounds in the leachate A (missed by chemical analysis) that were not readily biodegradable even by activated sludge consortium should not be excluded.

Content of phenolic compounds and free polyamines in black chokeberry (Aronia melanocarpa) after application of polyamine biosynthesis regulators.

PubMed

Hudec, Jozef; Bakos, Dusan; Mravec, Dusan; Kobida, L'ubomír; Burdová, Maria; Turianica, Ivan; Hlusek, Jaroslav

2006-05-17

The total contents of anthocyanins, flavonoids, and phenolics in 60 samples of black chokeberries (Aronia melanocarpa), after treating with catabolites of polyamine biosynthesis (KPAb) and ornithine decarboxylase inhibitor, were analyzed spectrophotometrically, and quercetin and free polyamine contents were analyzed by RP-HPLC with UV detection. The average total contents of the individual substances and phenolic subgroups in control berries were as follows (mg x kg(-1)): anthocyanines, 6408; flavonoids, 664; phenolics, 37,600; quercetin, 349. KPAb decreased total contents of anthocyanines and phenolics only slightly but significantly increased the content of flavonoids. This caused an important change in the abundance of flavonoids in the pigment complex. The absolute content of quercetin was increased, but its ratio to flavonoids content was decreased. Ornithine decarboxylase inhibitor had a markedly different effect as it significantly increased total content of anthocyanins and total phenolics, inhibited the total content of free polyamines, and stimulated the processes of saccharides transformation to phenolic pigments.

Pyrolysis-high resolution gas chromatography and pyrolysis gas chromatography-mass spectrometry of kerogens and kerogen precursors

NASA Technical Reports Server (NTRS)

Van De Meent, D.; Brown, S. C.; Philp, R. P.; Simoneit, B. R. T.

1980-01-01

A series of kerogens and kerogen precursors isolated from DSDP samples, oil shales and recent algal mats have been examined by Curie point pyrolysis-high resolution gas chromatography and gas chromatography-mass spectrometry. This study has shown that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques. The marine (algal) kerogens yield principally aliphatic products and the terrestrial kerogens yield more aromatic and phenolic products with some n-alkanes and n-alkenes. The yields of n-alkanes and n-alkenes increase and phenols decrease with increasing geologic age, however, pyrolysis-GC cannot be used to characterize the influence of short term diagenesis on the kerogen structure.

Asphaltenes-based polymer nano-composites

DOEpatents

Bowen, III, Daniel E

2013-12-17

Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

Composite Nozzle/Thrust Chambers Analyzed for Low-Cost Boosters

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

1999-01-01

The Low Cost Booster Technology Program is an initiative to minimize the cost of future liquid engines by using advanced materials and innovative designs, and by reducing engine complexity. NASA Marshall Space Flight Center s 60K FASTRAC Engine is one example where these design philosophies have been put into practice. This engine burns a liquid kerosene/oxygen mixture. It uses a one-piece, polymer composite thrust chamber/nozzle that is constructed of a tape-wrapped silica phenolic liner, a metallic injector interface ring, and a filament-wound epoxy overwrap. A cooperative effort between NASA Lewis Research Center s Structures Division and Marshall is underway to perform a finite element analysis of the FASTRAC chamber/nozzle under all the loading and environmental conditions that it will experience during its lifetime. The chamber/nozzle is a complex composite structure. Of its three different materials, the two composite components have distinctly different fiber architectures and, consequently, require separate material model descriptions. Since the liner is tape wrapped, it is orthotropic in the nozzle global coordinates; and since the overwrap is filament wound, it is treated as a monoclinic material. Furthermore, the wind angle on the overwrap varies continuously along the length of the chamber/nozzle.

Coupled electrokinetics-adsorption technique for simultaneous removal of heavy metals and organics from saline-sodic soil.

PubMed

Lukman, Salihu; Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Bukhari, Alaadin

2013-01-01

In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils.

Photo-oxidation method using MoS2 nanocluster materials

DOEpatents

Wilcoxon, Jess P.

2001-01-01

A method of photo-oxidizing a hydrocarbon compound is provided by dispersing MoS.sub.2 nanoclusters in a solvent containing a hydrocarbon compound contaminant to form a stable solution mixture and irradiating the mixture to photo-oxide the hydrocarbon compound. Hydrocarbon compounds of interest include aromatic hydrocarbon and chlorinated hydrocarbons. MoS.sub.2 nanoclusters with an average diameter less than approximately 10 nanometers are shown to be effective in decomposing potentially toxic aromatic and chlorinated hydrocarbons, such as phenol, pentachlorophenol, chlorinated biphenols, and chloroform, into relatively non-toxic compounds. The irradiation can occur by exposing the MoS.sub.2 nanoclusters and hydrocarbon compound mixture with visible light. The MoS.sub.2 nanoclusters can be introduced to the toxic hydrocarbons as either a MoS.sub.2 solution or deposited on a support material.

Evaluation of Pyrolysis Oil as Carbon Source for Fungal Fermentation

PubMed Central

Dörsam, Stefan; Kirchhoff, Jennifer; Bigalke, Michael; Dahmen, Nicolaus; Syldatk, Christoph; Ochsenreither, Katrin

2016-01-01

Pyrolysis oil, a complex mixture of several organic compounds, produced during flash pyrolysis of organic lignocellulosic material was evaluated for its suitability as alternative carbon source for fungal growth and fermentation processes. Therefore several fungi from all phyla were screened for their tolerance toward pyrolysis oil. Additionally Aspergillus oryzae and Rhizopus delemar, both established organic acid producers, were chosen as model organisms to investigate the suitability of pyrolysis oil as carbon source in fungal production processes. It was observed that A. oryzae tolerates pyrolysis oil concentrations between 1 and 2% depending on growth phase or stationary production phase, respectively. To investigate possible reasons for the low tolerance level, eleven substances from pyrolysis oil including aldehydes, organic acids, small organic compounds and phenolic substances were selected and maximum concentrations still allowing growth and organic acid production were determined. Furthermore, effects of substances to malic acid production were analyzed and compounds were categorized regarding their properties in three groups of toxicity. To validate the results, further tests were also performed with R. delemar. For the first time it could be shown that small amounts of phenolic substances are beneficial for organic acid production and A. oryzae might be able to degrade isoeugenol. Regarding pyrolysis oil toxicity, 2-cyclopenten-1-on was identified as the most toxic compound for filamentous fungi; a substance never described for anti-fungal or any other toxic properties before and possibly responsible for the low fungal tolerance levels toward pyrolysis oil. PMID:28066378

Evaluation of Pyrolysis Oil as Carbon Source for Fungal Fermentation.

PubMed

Dörsam, Stefan; Kirchhoff, Jennifer; Bigalke, Michael; Dahmen, Nicolaus; Syldatk, Christoph; Ochsenreither, Katrin

2016-01-01

Pyrolysis oil, a complex mixture of several organic compounds, produced during flash pyrolysis of organic lignocellulosic material was evaluated for its suitability as alternative carbon source for fungal growth and fermentation processes. Therefore several fungi from all phyla were screened for their tolerance toward pyrolysis oil. Additionally Aspergillus oryzae and Rhizopus delemar , both established organic acid producers, were chosen as model organisms to investigate the suitability of pyrolysis oil as carbon source in fungal production processes. It was observed that A. oryzae tolerates pyrolysis oil concentrations between 1 and 2% depending on growth phase or stationary production phase, respectively. To investigate possible reasons for the low tolerance level, eleven substances from pyrolysis oil including aldehydes, organic acids, small organic compounds and phenolic substances were selected and maximum concentrations still allowing growth and organic acid production were determined. Furthermore, effects of substances to malic acid production were analyzed and compounds were categorized regarding their properties in three groups of toxicity. To validate the results, further tests were also performed with R. delemar . For the first time it could be shown that small amounts of phenolic substances are beneficial for organic acid production and A. oryzae might be able to degrade isoeugenol. Regarding pyrolysis oil toxicity, 2-cyclopenten-1-on was identified as the most toxic compound for filamentous fungi; a substance never described for anti-fungal or any other toxic properties before and possibly responsible for the low fungal tolerance levels toward pyrolysis oil.

Recycling of phenolic compounds in Borneo's tropical peat swamp forests.

PubMed

Yule, Catherine M; Lim, Yau Yan; Lim, Tse Yuen

2018-02-07

Tropical peat swamp forests (TPSF) are globally significant carbon stores, sequestering carbon mainly as phenolic polymers and phenolic compounds (particularly as lignin and its derivatives) in peat layers, in plants, and in the acidic blackwaters. Previous studies show that TPSF plants have particularly high levels of phenolic compounds which inhibit the decomposition of organic matter and thus promote peat accumulation. The studies of phenolic compounds are thus crucial to further understand how TPSF function with respect to carbon sequestration. Here we present a study of cycling of phenolic compounds in five forests in Borneo differing in flooding and acidity, leaching of phenolic compounds from senescent Macaranga pruinosa leaves, and absorption of phenolics by M. pruinosa seedlings. The results of the study show that total phenolic content (TPC) in soil and leaves of three species of Macaranga were highest in TPSF followed by freshwater swamp forest and flooded limestone forest, then dry land sites. Highest TPC values were associated with acidity (in TPSF) and waterlogging (in flooded forests). Moreover, phenolic compounds are rapidly leached from fallen senescent leaves, and could be reabsorbed by tree roots and converted into more complex phenolics within the leaves. Extreme conditions-waterlogging and acidity-may facilitate uptake and synthesis of protective phenolic compounds which are essential for impeded decomposition of organic matter in TPSF. Conversely, the ongoing drainage and degradation of TPSF, particularly for conversion to oil palm plantations, reverses the conditions necessary for peat accretion and carbon sequestration.

The use of a tannin crude extract from Cistus ladanifer L. to protect soya-bean protein from degradation in the rumen.

PubMed

Dentinho, M T P; Moreira, O C; Pereira, M S; Bessa, R J B

2007-06-01

Cistus ladanifer L. (CL) is a perennial shrub abundant in dry woods and dry land of Mediterranean zone, with high level of tannins. Tannins bind to protein, preventing its degradation in the digestive compartments. This tannin/protein complex may be advantageous when partially protecting good-quality feed protein from excessive rumen protein degradation. The objective of this trial was to use a CL phenol crude extract to prevent excessive rumen degradation of soya-bean meal protein. The phenolic compounds were extracted using an acetone/water solution (70:30, v/v). Soya-bean meal was then treated with this crude CL extract, containing 640 g of total phenols (TP) per kg of dry matter (DM), in order to obtain mixtures with 0, 12.5, 25, 50, 100 and 150 g of TP per kg DM. Three rumen-cannulated rams were used to assess in sacco rumen degradability of DM and nitrogen (N). The three-step in vitro procedure was used to determine intestinal digestibility. Increasing extract concentrations quadratically decreased the N-soluble fraction a (R2 = 0.96, P = 0.0001) and increased the non-soluble degradable fraction b (R2 = 0.92, P = 0.005). The rate of degradation c linearly decreased with CL extract doses (R2 = 0.44, P = 0.0065). For the effective rumen degradability of N, a linear reduction (R2 = 0.94, P < 0.0001) was observed. The in vitro intestinal digestibility of protein (ivID) quadratically decreased (R2 = 0.99, P < 0.0001) with TP inclusion and the rumen undegradable protein (RUP) showed a quadratic increase (R2 = 0.94, P = 0.0417). Total intestinal protein availability, computed from the RUP and ivID, linearly decreased with TP inclusion level (R2 = 0.45, P = 0.0033).

Fabrication of a Microbial Biosensor Based on QD-MWNT Supports by a One-Step Radiation Reaction and Detection of Phenolic Compounds in Red Wines

PubMed Central

Kim, Seul-Ki; Kwen, Hai-Doo; Choi, Seong-Ho

2011-01-01

An Acaligense sp.-immobilized biosensor was fabricated based on QD-MWNT composites as an electron transfer mediator and a microbe immobilization support by a one-step radiation reaction and used for sensing phenolic compounds in commercial red wines. First, a quantum dot-modified multi-wall carbon nanotube (QD-MWNT) composite was prepared in the presence of MWNT by a one-step radiation reaction in an aqueous solution at room temperature. The successful preparation of the QD-MWNT composite was confirmed by XPS, TEM, and elemental analysis. Second, the microbial biosensor was fabricated by immobilization of Acaligense sp. on the surface of the composite thin film of a glassy carbon (GC) electrode, which was prepared by a hand casting method with a mixture of the previously obtained composite and Nafion solution. The sensing ranges of the microbial biosensor based on CdS-MWNT and Cu2S-MWNT supports were 0.5–5.0 mM and 0.7–10 mM for phenol in a phosphate buffer solution, respectively. Total concentration of phenolic compounds contained in commercial red wines was also determined using the prepared microbial immobilized biosensor. PMID:22319395

Effects of particle size of fiberglass-resin powder from PCBs on the properties and volatile behavior of phenolic molding compound.

PubMed

Guo, Jie; Rao, Qunli; Xu, Zhenming

2010-03-15

Fiberglass-resin powder (FR powder), a mixture of resin powder and glass fibers reclaimed from pulverized waste printed circuit boards (PCBs), is used as a partial substitute of wood flour in the production of modified phenolic molding compound (MPMC). The results show that incorporation of FR powder into MPMC as a filler enhances the thermal stability represented by heat deflection temperature (HDT). MPMC with FR powder smaller than 0.07 mm shows better properties, with a flexural strength of 73 MPa, a charpy notched impact strength of 3.0 kJ/m(2), a HDT of 167 degrees C, and a dielectric strength of 3.7 MV/m, all of which meet the standard data. Thermogravimetric analysis shows that thermal degradation of MPMC mainly includes three steps, and over 55% weight loss of MPMC occurs between temperatures of 370 degrees C and 575 degrees C. Phenol is the main volatile compound released from molding powder during the production of molding product. After molding powder cures to molding product, low level of residual phenol is detected. All the results indicate that the MPMC can be used as a new type of molding compound. (c) 2009 Elsevier B.V. All rights reserved.

Estrogenic activities of chemicals related to food contact plastics and rubbers tested by the yeast two-hybrid assay.

PubMed

Ogawa, Yuko; Kawamura, Yoko; Wakui, Chiseko; Mutsuga, Motoh; Nishimura, Tetsuji; Tanamoto, Kenichi

2006-04-01

Food contact plastics and rubbers possibly contain many kinds of chemicals such as monomers, oligomers, additives, degradation products of polymers and additives, and impurities. Among them, bisphenol A, nonylphenol, benzylbutyl phthalate, styrene oligomers and hydroxylated benzophenones have been reported to possess estrogenic activities. In this study, other chemicals related to food contact plastics and rubbers, and their metabolites induced by the S9-mixture were tested for their estrogenic activities using the yeast two-hybrid assay. Among the 150 chemicals, 10 chemicals such as bis(4-hydroxyphenyl) methane, 4-cyclohexylphenol, 4-phenylphenol, 4,4'-isopropylidenediphenol alkylphosphite, two type of styrenated phenol (including mono type), tris(nonylphenyl) phosphite, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone and 2,4-diphenyl-4-methyl-1-pentene, their metabolites and the metabolites of 6 other chemicals, such as 2-(phenylmethyl) phenol, styrenated phenol (di and tri type), 1-(N-phenylamino)naphthalene, 4-tert-butylphenylsalicylate, nonylphenol ethoxylates and 2-methyl-6-tert-butylphenol, displayed estrogenic activities. All of them contained a phenol group in their chemical structures or formed one easily by hydrolysis or metabolism. However, most of the chemicals related to food contact plastics and rubbers, and their metabolites did not show any estrogenicity.

METHODS AND TECHNIQUES FOR DEALING WITH THE UNIDENTIFIED FRACTION OF COMPLEX MIXTURES

EPA Science Inventory

For the vast majority of highly complex environmental mixtures to which humans are exposed, significant portions of the mixture are unidentified. Although toxicological data on the mixture itself are desired for risk assessment, such data, even on a similar mixture, are rarely a...

Chromatographic fingerprinting through chemometric techniques for herbal slimming pills: A way of adulterant identification.

PubMed

Shekari, Nafiseh; Vosough, Maryam; Tabar Heidar, Kourosh

2018-05-01

In the current study, gas chromatography-mass spectrometry (GC-MS) fingerprinting of herbal slimming pills assisted by chemometric methods has been presented. Deconvolution of two-way chromatographic signals of nine herbal slimming pills into pure chromatographic and spectral patterns was performed. The peak clusters were resolved using multivariate curve resolution-alternating least squares (MCR-ALS) by employing appropriate constraints. It was revealed that more useful chemical information about the composition of the slimming pills can be obtained by employing sophisticated GC-MS method coupled with proper chemometric tools yielding the extended number of identified constituents. The thorough fingerprinting of the complex mixtures proved the presence of some toxic or carcinogen components, such as toluene, furfural, furfuryl alcohol, styrene, itaconic anhydride, citraconic anhydride, trimethyl phosphate, phenol, pyrocatechol, p-propenylanisole and pyrogallol. In addition, some samples were shown to be adulterated with undeclared ingredients, including stimulants, anorexiant and laxatives such as phenolphthalein, amfepramone, caffeine and sibutramine. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparison of the Nanostructure and Mechanical Performance of Highly Exfoliated Epoxy-Clay Nanocomposites Prepared by Three Different Protocols

PubMed Central

Shiravand, Fatemeh; Hutchinson, John M.; Calventus, Yolanda; Ferrando, Francesc

2014-01-01

Three different protocols for the preparation of polymer layered silicate nanocomposites based upon a tri-functional epoxy resin, triglycidyl para-amino phenol (TGAP), have been compared in respect of the cure kinetics, the nanostructure and their mechanical properties. The three preparation procedures involve 2 wt% and 5 wt% of organically modified montmorillonite (MMT), and are: isothermal cure at selected temperatures; pre-conditioning of the resin-clay mixture before isothermal cure; incorporation of an initiator of cationic homopolymerisation, a boron tri-fluoride methyl amine complex, BF3·MEA, within the clay galleries. It was found that features of the cure kinetics and of the nanostructure correlate with the measured impact strength of the cured nanocomposites, which increases as the degree of exfoliation of the MMT is improved. The best protocol for toughening the TGAP/MMT nanocomposites is by the incorporation of 1 wt% BF3·MEA into the clay galleries of nanocomposites containing 2 wt% MMT. PMID:28788672

Characterization of volatile compounds responsible for the aroma in naturally fermented sausages by gas chromatography-olfactometry.

PubMed

Olivares, Alicia; Navarro, José Luis; Flores, Mónica

2015-03-01

The objective of this study was to characterize naturally fermented dry sausages produced without the use of microbial starters and to determine which odour-active compounds are responsible for their aroma. The traditional manufacture was responsible for different chemical characteristics and consumer's acceptance. The volatile compounds detected in the headspace comprised a complex mixture of volatile compounds derived from bacterial metabolism (mainly esterase activity of Staphyloccoci), spices and lipid auto-oxidation. The odour-active volatile compounds were identified using gas chromatography coupled to olfactometry (GC-O) using the detection frequency method. The aroma profile was characterized by the presence of several compounds such as acetic acid, ethyl butanoate, hexanal, methional, 1-octen-3-ol, benzeneacetaldehyde and 4-methyl-phenol. However, naturally fermented sausages were also characterized by numerous esters, both ethyl and methyl esters, which impart a wide variety of fruity notes. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Comparison of the Nanostructure and Mechanical Performance of Highly Exfoliated Epoxy-Clay Nanocomposites Prepared by Three Different Protocols.

PubMed

Shiravand, Fatemeh; Hutchinson, John M; Calventus, Yolanda; Ferrando, Francesc

2014-05-30

Three different protocols for the preparation of polymer layered silicate nanocomposites based upon a tri-functional epoxy resin, triglycidyl para -amino phenol (TGAP), have been compared in respect of the cure kinetics, the nanostructure and their mechanical properties. The three preparation procedures involve 2 wt% and 5 wt% of organically modified montmorillonite (MMT), and are: isothermal cure at selected temperatures; pre-conditioning of the resin-clay mixture before isothermal cure; incorporation of an initiator of cationic homopolymerisation, a boron tri-fluoride methyl amine complex, BF₃·MEA, within the clay galleries. It was found that features of the cure kinetics and of the nanostructure correlate with the measured impact strength of the cured nanocomposites, which increases as the degree of exfoliation of the MMT is improved. The best protocol for toughening the TGAP/MMT nanocomposites is by the incorporation of 1 wt% BF₃·MEA into the clay galleries of nanocomposites containing 2 wt% MMT.

Enantioselective separation of defined endocrine-disrupting nonylphenol isomers.

PubMed

Acir, Ismail-Hakki; Wüst, Matthias; Guenther, Klaus

2016-08-01

Nonylphenol is in the focus of worldwide endocrine-disrupter research and accounted for as a priority hazardous substance of the Water Framework Directive of the European Union. Technical nonylphenol consists of a very complex mixture of isomers and enantiomers. As estrogenic effect and degradation behavior in environmental processes of single nonylphenols are heavily dependent on the structure of the nonyl side chain, it is absolutely necessary to consider the nonylphenol problem from an isomer and enantiomer-specific viewpoint. In this study, an enantiomer-specific separation of eight defined synthesized nonylphenol isomers by five different special chiral cyclodextrin columns was performed underivatized and after methylation, silylation, and acylation. This work demonstrates that three columns out of the investigated five show an excellent separation behavior for the studied different nonylphenol isomers and can be used for the enantiomer-specific determination of nonylphenols in food, other biological matrices, and environmental samples in the future. Graphical abstract Enantiomeric pair of 4-NP170 (4-[1-ethyl-1,3,3-trimethylbutyl]phenol).

Interactions between wine phenolic compounds and human saliva in astringency perception.

PubMed

García-Estévez, Ignacio; Ramos-Pineda, Alba María; Escribano-Bailón, María Teresa

2018-03-01

Astringency is a complex perceptual phenomenon involving several sensations that are perceived simultaneously. The mechanism leading to these sensations has been thoroughly and controversially discussed in the literature and it is still not well understood since there are many contributing factors. Although we are still far from elucidating the mechanisms whereby astringency develops, the interaction between phenolic compounds and proteins (from saliva, oral mucosa or cells) seems to be most important. This review summarizes the recent trends in the protein-phenol interaction, focusing on the effect of the structure of the phenolic compound on the interaction with salivary proteins and on methodologies based on these interactions to determine astringency.

Strategy of Pseudomonas pseudoalcaligenes C70 for effective degradation of phenol and salicylate

PubMed Central

Heinaru, Eeva; Naanuri, Eve; Mehike, Maris; Leito, Ivo; Heinaru, Ain

2017-01-01

Phenol- and naphthalene-degrading indigenous Pseudomonas pseudoalcaligenes strain C70 has great potential for the bioremediation of polluted areas. It harbours two chromosomally located catechol meta pathways, one of which is structurally and phylogenetically very similar to the Pseudomonas sp. CF600 dmp operon and the other to the P. stutzeri AN10 nah lower operon. The key enzymes of the catechol meta pathway, catechol 2,3-dioxygenase (C23O) from strain C70, PheB and NahH, have an amino acid identity of 85%. The metabolic and regulatory phenotypes of the wild-type and the mutant strain C70ΔpheB lacking pheB were evaluated. qRT-PCR data showed that in C70, the expression of pheB- and nahH-encoded C23O was induced by phenol and salicylate, respectively. We demonstrate that strain C70 is more effective in the degradation of phenol and salicylate, especially at higher substrate concentrations, when these compounds are present as a mixture; i.e., when both pathways are expressed. Moreover, NahH is able to substitute for the deleted PheB in phenol degradation when salicylate is also present in the growth medium. The appearance of a yellow intermediate 2-hydroxymuconic semialdehyde was followed by the accumulation of catechol in salicylate-containing growth medium, and lower expression levels and specific activities of the C23O of the sal operon were detected. However, the excretion of the toxic intermediate catechol to the growth medium was avoided when the growth medium was supplemented with phenol, seemingly due to the contribution of the second meta pathway encoded by the phe genes. PMID:28257519

Quantification of phenolic acids and antioxidant potential of inbred, hybrid and composite cultivars of maize under different nitrogen regimes.

PubMed

Ganie, Arshid Hussain; Yousuf, Peerzada Yasir; Ahad, Amjid; Pandey, Renu; Ahmad, Sayeed; Aref, Ibrahim M; Noor, Jewel Jameeta; Iqbal, Muhammad

2016-11-01

Maize (Zea mays L.) is a multipurpose crop, which is immensely used worldwide for its nutritional as well as medicinal properties. This study evaluates the effect of varying concentrations of nitrogen (N) on accumulation of phenolic acids and antioxidant activity in different maize cultivars, including inbreds, hybrids and a composite, which were grown in natural light under controlled temperature (30°C/20°C D/N) and humidity (80%), with sufficient (4.5mM) and low (0.05mM) nitrogen supply. Seeds of different cultivars were powdered and extracted in a methanol:water (80:20) mixture through reflux at 60-75°C, and the extracts obtained were subjected to high performance thin layer chromatography (HPTLC), using ethyl acetate: acetic acid: formic acid: water (109:16:12:31) solvent system for the separation of phenolic acids. Antioxidant activity of the extracts was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2-scavenging activity assays. At sufficient nitrogen condition, the contents of different phenolic acids were higher in the composite cultivar (8.7 mg g-1 d.wt. in gallic acid to 39.3 mg g-1 d.wt. in cinnamic and salicylic acids) than in inbreds and hybrids. Under low nitrogen condition, the phenolic acids contents declined significantly in inbreds and hybrids, but remained almost unaffected in the composite. The antioxidant activity was also the maximum in the composite, and declined similarly as phenolic acids under low nitrogen supply, showing a significant reduction in inbreds and hybrids only. Therefore, the maize composite has a potential for being used as a nutraceutical in human-health sector.

Using magnetic beads to reduce reanut allergens from peanut extracts.

USDA-ARS?s Scientific Manuscript database

Ferric irons (Fe3+) and phenolic compounds have been shown to bind to peanut allergens. An easy way to isolate peanut allergens is by use of magnetic beads attached with or without phenolics to capture peanut allergens or allergen-Fe3+ complexes, thus, achieving the goal of producing peanut extracts...

A review of catalytic hydrodeoxygenation of lignin-derived phenols from biomass pyrolysis.

PubMed

Bu, Quan; Lei, Hanwu; Zacher, Alan H; Wang, Lu; Ren, Shoujie; Liang, Jing; Wei, Yi; Liu, Yupeng; Tang, Juming; Zhang, Qin; Ruan, Roger

2012-11-01

Catalytic hydrodeoxygenation (HDO) of lignin-derived phenols which are the lowest reactive chemical compounds in biomass pyrolysis oils has been reviewed. The hydrodeoxygenation (HDO) catalysts have been discussed including traditional HDO catalysts such as CoMo/Al(2)O(3) and NiMo/Al(2)O(3) catalysts and transition metal catalysts (noble metals). The mechanism of HDO of lignin-derived phenols was analyzed on the basis of different model compounds. The kinetics of HDO of different lignin-derived model compounds has been investigated. The diversity of bio-oils leads to the complexities of HDO kinetics. The techno-economic analysis indicates that a series of major technical and economical efforts still have to be investigated in details before scaling up the HDO of lignin-derived phenols in existed refinery infrastructure. Examples of future investigation of HDO include significant challenges of improving catalysts and optimum operation conditions, further understanding of kinetics of complex bio-oils, and the availability of sustainable and cost-effective hydrogen source. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of abscisic acid, gibberellin, ethylene and their interactions on production of phenolic acids in salvia miltiorrhiza bunge hairy roots.

PubMed

Liang, Zongsuo; Ma, Yini; Xu, Tao; Cui, Beimi; Liu, Yan; Guo, Zhixin; Yang, Dongfeng

2013-01-01

Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants because of its excellent performance in treating coronary heart disease. Phenolic acids mainly including caffeic acid, rosmarinic acid and salvianolic acid B are a group of active ingredients in S. miltiorrhiza. Abscisic acid (ABA), gibberellin (GA) and ethylene are three important phytohormones. In this study, effects of the three phytohormones and their interactions on phenolic production in S. miltiorrhiza hairy roots were investigated. The results showed that ABA, GA and ethylene were all effective to induce production of phenolic acids and increase activities of PAL and TAT in S. miltiorrhiza hairy roots. Effects of phytohormones were reversed by their biosynthetic inhibitors. Antagonistic actions between the three phytohormones played important roles in the biosynthesis of phenolic acids. GA signaling is necessary for ABA and ethylene-induced phenolic production. Yet, ABA and ethylene signaling is probably not necessary for GA3-induced phenolic production. The complex interactions of phytohormones help us reveal regulation mechanism of secondary metabolism and scale-up production of active ingredients in plants.

Effects of Abscisic Acid, Gibberellin, Ethylene and Their Interactions on Production of Phenolic Acids in Salvia miltiorrhiza Bunge Hairy Roots

PubMed Central

Xu, Tao; Cui, Beimi; Liu, Yan; Guo, Zhixin; Yang, Dongfeng

2013-01-01

Salvia miltiorrhiza is one of the most important traditional Chinese medicinal plants because of its excellent performance in treating coronary heart disease. Phenolic acids mainly including caffeic acid, rosmarinic acid and salvianolic acid B are a group of active ingredients in S. miltiorrhiza. Abscisic acid (ABA), gibberellin (GA) and ethylene are three important phytohormones. In this study, effects of the three phytohormones and their interactions on phenolic production in S. miltiorrhiza hairy roots were investigated. The results showed that ABA, GA and ethylene were all effective to induce production of phenolic acids and increase activities of PAL and TAT in S. miltiorrhiza hairy roots. Effects of phytohormones were reversed by their biosynthetic inhibitors. Antagonistic actions between the three phytohormones played important roles in the biosynthesis of phenolic acids. GA signaling is necessary for ABA and ethylene-induced phenolic production. Yet, ABA and ethylene signaling is probably not necessary for GA3-induced phenolic production. The complex interactions of phytohormones help us reveal regulation mechanism of secondary metabolism and scale-up production of active ingredients in plants. PMID:24023778

Molecular modeling studies of substrate binding by penicillin acylase.

PubMed

Chilov, G G; Stroganov, O V; Svedas, V K

2008-01-01

Molecular modeling has revealed intimate details of the mechanism of binding of natural substrate, penicillin G (PG), in the penicillin acylase active center and solved questions raised by analysis of available X-ray structures, mimicking Michaelis complex, which substantially differ in the binding pattern of the PG leaving group. Three MD trajectories were launched, starting from PDB complexes of the inactive mutant enzyme with PG (1FXV) and native penicillin acylase with sluggishly hydrolyzed substrate analog penicillin G sulfoxide (1GM9), or from the complex obtained by PG docking. All trajectories converged to a similar PG binding mode, which represented the near-to-attack conformation, consistent with chemical criteria of how reactive Michaelis complex should look. Simulated dynamic structure of the enzyme-substrate complex differed significantly from 1FXV, resembling rather 1GM9; however, additional contacts with residues bG385, bS386, and bN388 have been found, which were missing in X-ray structures. Combination of molecular docking and molecular dynamics also clarified the nature of extremely effective phenol binding in the hydrophobic pocket of penicillin acylase, which lacked proper explanation from crystallographic experiments. Alternative binding modes of phenol were probed, and corresponding trajectories converged to a single binding pattern characterized by a hydrogen bond between the phenol hydroxyl and the main chain oxygen of bS67, which was not evident from the crystal structure. Observation of the trajectory, in which phenol moved from its steady bound to pre-dissociation state, mapped the consequence of molecular events governing the conformational transitions in a coil region a143-a146 coupled to substrate binding and release of the reaction products. The current investigation provided information on dynamics of the conformational transitions accompanying substrate binding and significance of poorly structured and flexible regions in maintaining catalytic framework.

Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole.

PubMed

Kalanithi, M; Rajarajan, M; Tharmaraj, P; Sheela, C D

2012-02-15

Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol(HL(1)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol(HL(2)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol(HL(3)). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry. Copyright © 2011 Elsevier B.V. All rights reserved.

A Statistical Approach for Judging Stability of Whole Mixture Chemical Composition over Time for Highly Complex Disinfection By-Product Mixtures from EPA's Four Lab Study

EPA Science Inventory

Chemical characterization of complex mixtures and assessment of stability over time of the characterized chemicals is crucial both to characterize exposure and to use data from one mixture as a surrogate for other similar mixtures. The chemical composition of test mixtures can va...

Oxidation of aquatic pollutants by ferrous-oxalate complexes under dark aerobic conditions.

PubMed

Lee, Jaesang; Kim, Jungwon; Choi, Wonyong

2014-06-15

This study evaluates the ability of Fe(II)-oxalate complexes for the generation of OH through oxygen reduction and the oxidative degradation of aquatic pollutants under dark aerobic conditions (i.e., with oxygen but without light). The degradation of 4-chlorophenol (4-CP) was rapid in the mixture of Fe(2+) and oxalate prepared using ultrapure water, but was absent without either Fe(2+) or oxalate. The formation of Fe(II)-oxalate complexes enables two-electron reduction of oxygen to generate H2O2 and subsequent production of OH. The significant inhibition of 4-CP degradation in the presence of H2O2 and OH scavenger confirms such mechanisms. The degradation experiments with varying [Fe(2+)], [oxalate], and initial pH demonstrated that the degradation rate depends on [Fe(II)(Ox)2(2-)], but the degree of degradation is primarily determined by [Fe(II)(Ox)2(2-)]+[Fe(II)(Ox)(0)]. Efficient degradation of diverse aquatic pollutants, especially phenolic pollutants, was observed in the Fe(II)-oxalate complexes system, wherein the oxidation efficacy was primarily correlated with the reaction rate constant between pollutant and OH. The effect of various organic ligands (oxalate, citrate, EDTA, malonate, and acetate) on the degradation kinetics of 4-CP was investigated. The highest efficiency of oxalate for the oxidative degradation is attributed to its high capability to enhance the reducing power and low reactivity with OH. Copyright © 2014 Elsevier B.V. All rights reserved.

Tall oil precursors and turpentine in black and white spruce

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conner, A.H.; Diehl, M.A.; Rowe, J.W.

1980-01-01

The heartwood of Picea mariana contained resin acids (1) 14, fatty acids (11) 2, esters 10, nonsaponifiables 13, and phenolic compounds 61%, whereas P. glauca contained (1) 12, (11) 1, esters 42, nonsaponifiables 13, and phenolic compounds 32%. The (1) consisted primarily of palustric, isopimaric, abietic,and dehydroabietic acids, and fatty acids were mainly oleic, linoleic, and 5,9,12-octadecatrienoic acids. Turpentine obtained from these species was primarily a mixture of alpha- and beta-pinene. Paraquat (111) treatment induced up to a 7-fold increase in the content of oleoresin of these species, but visual indications of lightwood were not observed. The components of turpentinemore » and Et/sub 2/0 extractives after (111) treatment were similar to those before treatment.« less

Environmentally relevant chemical mixtures of concern in waters of United States tributaries to the Great Lakes

USGS Publications Warehouse

Elliott, Sarah M.; Brigham, Mark E.; Kiesling, Richard L.; Schoenfuss, Heiko L.; Jorgenson, Zachary G.

2018-01-01

The North American Great Lakes are a vital natural resource that provide fish and wildlife habitat, as well as drinking water and waste assimilation services for millions of people. Tributaries to the Great Lakes receive chemical inputs from various point and nonpoint sources, and thus are expected to have complex mixtures of chemicals. However, our understanding of the co‐occurrence of specific chemicals in complex mixtures is limited. To better understand the occurrence of specific chemical mixtures in the US Great Lakes Basin, surface water from 24 US tributaries to the Laurentian Great Lakes was collected and analyzed for diverse suites of organic chemicals, primarily focused on chemicals of concern (e.g., pharmaceuticals, personal care products, fragrances). A total of 181 samples and 21 chemical classes were assessed for mixture compositions. Basin wide, 1664 mixtures occurred in at least 25% of sites. The most complex mixtures identified comprised 9 chemical classes and occurred in 58% of sampled tributaries. Pharmaceuticals typically occurred in complex mixtures, reflecting pharmaceutical‐use patterns and wastewater facility outfall influences. Fewer mixtures were identified at lake or lake‐influenced sites than at riverine sites. As mixture complexity increased, the probability of a specific mixture occurring more often than by chance greatly increased, highlighting the importance of understanding source contributions to the environment. This empirically based analysis of mixture composition and occurrence may be used to focus future sampling efforts or mixture toxicity assessments. 

Evaluation of the nephrotoxicity of complex mixtures containing organics and metals: advantages and disadvantages of the use of real-world complex mixtures.

PubMed

Simmons, J E; Yang, R S; Berman, E

1995-02-01

As part of a multidisciplinary health effects study, the nephrotoxicity of complex industrial waste mixtures was assessed. Adult, male Fischer 344 rats were gavaged with samples of complex industrial waste and nephrotoxicity evaluated 24 hr later. Of the 10 tested samples, 4 produced increased absolute or relative kidney weight, or both, coupled with a statistically significant alteration in at least one of the measured serum parameters (urea nitrogen (BUN), creatinine (CREAT), and BUN/CREAT ratio). Although the waste samples had been analyzed for a number of organic chemicals and 7 of the 10 samples were analyzed also for 12 elemental metals and metalloids, their nephrotoxicity was not readily predicted from the partial chemical characterization data. Because the chemical form or speciation of the metals was unknown, it was not possible to estimate their contribution to the observed biological response. Various experimental approaches, including use of real-world complex mixtures, chemically defined synthetic mixtures, and simple mixtures, will be necessary to adequately determine the potential human health risk from exposure to complex chemical mixtures.

Antioxidant potential and quality characteristics of vegetable-enriched corn-based extruded snacks.

PubMed

Bisharat, G I; Lazou, A E; Panagiotou, N M; Krokida, M K; Maroulis, Z B

2015-07-01

Phenolic content, antioxidant activity and sensory characteristics of vegetable-enriched extrudates were investigated as a result of extrusion conditions, including extrusion temperature (140-180 °C), screw rotation speed (150-250 rpm) and feed moisture content (14-19 % w.b.). Broccoli flour and olive paste was used in mixtures with corn flour at a ratio of 4 to 10 % (broccoli/corn) and 4 to 8 % (olive paste/corn). A simple power model was developed for the prediction of phenolic content and antioxidant activity of extrudates by extrusion conditions and feed composition. Phenolic content and antioxidant activity of broccoli enriched extrudates increased with extrusion temperature and broccoli addition and decreased with feed moisture content. The antioxidant activity of olive paste extrudates increased with material ratio and decreased with feed moisture content and screw rotation. Sensory porosity, homogenous structure, crispness, cohesiveness and melting decreased with feed moisture content, while the latter increased the mealy flavor and hardness of extrudates. Acceptable snacks containing broccoli flour or olive paste can be produced by selecting the appropriate process conditions.

Differentiation of Wines Treated with Wood Chips Based on Their Phenolic Content, Volatile Composition, and Sensory Parameters.

PubMed

Kyraleou, Maria; Kallithraka, Stamatina; Chira, Kleopatra; Tzanakouli, Eleni; Ligas, Ioannis; Kotseridis, Yorgos

2015-12-01

The effects of both wood chips addition and contact time on phenolic content, volatile composition, color parameters, and organoleptic character of red wine made by a native Greek variety (Agiorgitiko) were evaluated. For this purpose, chips from American, French, Slavonia oak, and Acacia were added in the wine after fermentation. A mixture consisting of 50% French and 50% Americal oak chips was also evaluated. In an attempt to categorize wine samples, various chemical parameters of wines and sensory parameters were studied after 1, 2, and 3 mo of contact time with chips. The results showed that regardless of the type of wood chips added in the wines, it was possible to differentiate the samples according to the contact time based on their phenolic composition and color parameters. In addition, wood-extracted volatile compounds seem to be the critical parameter that could separate the samples according to the wood type. The wines that were in contact with Acacia and Slavonia chips could be separated from the rest mainly due to their distinct sensory characters. © 2015 Institute of Food Technologists®

Macro-kinetic investigation on phenol uptake from air by biofiltration: Influence of superficial gas flow rate and inlet pollutant concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zilli, M.; Fabiano, B.; Ferraiolo, A.

1996-02-20

The macro-kinetic behavior of phenol removal from a synthetic exhaust gas was investigated theoretically as well as experimentally by means of two identical continuously operating laboratory-scale biological filter bed columns. A mixture of peat and glass beads was used as filter material. After sterilization it was inoculated with a pure strain of Pseudomonas putida, as employed in previous experimental studies. To determine the influence of the superficial gas flow rate on biofilter performance and to evaluate the phenol concentration profiles along the column, two series of continuous tests were carried out varying either the inlet phenol concentration, up to 1,650more » mg {center_dot} m{sup {minus}3}, or the superficial gas flow rate, from 30 to 460 m{sup 3} {center_dot} m{sup {minus}2} {center_dot} h{sup {minus}1}. The elimination capacity of the biofilter is proved by a maximum volumetric phenol removal rate of 0.73 kg {center_dot} m{sup {minus}3} {center_dot} h{sup {minus}1}. The experimental results are consistent with a biofilm model incorporating first-order substrate elimination kinetics. The model may be considered a useful tool in scaling-up a biofiltration system. Furthermore, the deodorization capacity of the biofilter was investigated, at inlet phenol concentrations up to 280 mg {center_dot} m{sup {minus}3} and superficial gas flow rates ranging from 30 to 92 m{sup 3} {center_dot} m{sup {minus}2} {center_dot} h{sup {minus}1}. The deodorization of the gas was achieved at a maximum inlet phenol concentration of about 255 mg {center_dot} m{sup {minus}3}, operating at a superficial gas flow rate of 30 m{sup 3} {center_dot} m{sup {minus}2} {center_dot} h{sup {minus}1}.« less

Insights into Supramolecular Sites Responsible for Complete Separation of Biomass-Derived Phenolics and Glucose in Metal-Organic Framework NU-1000.

PubMed

Yabushita, Mizuho; Li, Peng; Durkin, Kathleen A; Kobayashi, Hirokazu; Fukuoka, Atsushi; Farha, Omar K; Katz, Alexander

2017-05-02

The molecular origins of adsorption of lignin-derived phenolics to metal-organic framework NU-1000 are investigated from aqueous solution as well as in competitive mode with glucose present in the same aqueous mixture. A comparison of adsorption equilibrium constants (K ads ) for phenolics functionalized with either carboxylic acid or aldehyde substituents demonstrated only a slight increase (less than a factor of 6) for the former according to both experiments and calculations. This small difference in K ads between aldehyde and carboxylic-acid substituted adsorbates is consistent with the pyrene unit of NU-1000 as the adsorption site, rather than the zirconia nodes, while at saturation coverage, the adsorption capacity suggests multiple guests per pyrene. Experimental standard free energies of adsorption directly correlated with the molecular size and electronic structure calculations confirmed this direct relationship, with the pyrene units as adsorption site. The underlying origins of this relationship are grounded in noncovalent π-π interactions as being responsible for adsorption, the same interactions present in the condensed phase of the phenolics, which to a large extent govern their heat of vaporization. Thus, NU-1000 acts as a preformed aromatic cavity for driving aromatic guest adsorption from aqueous solution and does so specifically without causing detectable glucose adsorption from aqueous solution, thereby achieving complete glucose-phenolics separations. The reusability of NU-1000 during an adsorption/desorption cycle was good, even with some of the phenolic compounds with greatest affinity not easiliy removed with water and ethanol washes at room temperature. A competitive adsorption experiment gave an upper bound for K ads for glucose of at most 0.18 M -1 , which can be compared with K ads for the phenolics investigated here, which fell in the range of 443-42 639 M -1 . The actual value of K ads for glucose may be much closer to zero given the lack of observed glucose uptake with NU-1000 as adsorbent.

Solar photocatalytic degradation of chlorophenols mixture (4-CP and 2,4-DCP): Mechanism and kinetic modelling.

PubMed

Abeish, Abdulbasit M; Ang, Ha Ming; Znad, Hussein

2015-01-01

The solar-photocatalytic degradation mechanisms and kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) using TiO2 have been investigated both individually and combined. The individual solar-photocatalytic degradation of both phenolic compounds showed that the reaction rates follow pseudo-first-order reaction. During the individual photocatalytic degradation of both 4-CP and 2,4-DCP under the same condition of TiO2 (0.5 g L(-1)) and light intensities (1000 mW cm(-2)) different intermediates were detected, three compounds associated with 4-CP (hydroquinone (HQ), phenol (Ph) and 4-chlorocatechol (4-cCat)) and two compounds associated with 2,4-DCP (4-CP and Ph). The photocatalytic degradation of the combined mixture (4-CP and 2,4-DCP) was also investigated at the same conditions and different 2,4-DCP initial concentrations. The results showed that the degradation rate of 4-CP decreases when the 2,4-DCP concentration increases. Furthermore, the intermediates detected were similar to that found in the individual degradation but with high Ph concentration. Therefore, a possible reaction mechanism for degradation of this combined mixture was proposed. Moreover, a modified Langmuir-Hinshelwood (L-H) kinetic model considering all detected intermediates was developed. A good agreement between experimental and estimated results was achieved. This model can be useful for scaling-up purposes more accurately as its considering the intermediates formed, which has a significant effect on degrading the main pollutants (4-CP and 2,4-DCP).

Condensed Tannins from Longan Bark as Inhibitor of Tyrosinase: Structure, Activity, and Mechanism.

PubMed

Chai, Wei-Ming; Huang, Qian; Lin, Mei-Zhen; Ou-Yang, Chong; Huang, Wen-Yang; Wang, Ying-Xia; Xu, Kai-Li; Feng, Hui-Ling

2018-01-31

In this study, the content, structure, antityrosinase activity, and mechanism of longan bark condensed tannins were evaluated. The findings obtained from mass spectrometry demonstrated that longan bark condensed tannins were mixtures of procyanidins, propelargonidins, prodelphinidins, and their acyl derivatives (galloyl and p-hydroxybenzoate). The enzyme analysis indicated that these mixtures were efficient, reversible, and mixed (competitive is dominant) inhibitor of tyrosinase. What's more, the mixtures showed good inhibitions on proliferation, intracellular enzyme activity and melanogenesis of mouse melanoma cells (B 16 ). From molecular docking, the results showed the interactions between inhibitors and tyrosinase were driven by hydrogen bond, electrostatic, and hydrophobic interactions. In addition, high levels of total phenolic and extractable condensed tannins suggested that longan bark might be a good source of tyrosinase inhibitor. This study would offer theoretical basis for the development of longan bark condensed tannins as novel food preservatives and medicines of skin diseases.

Blanching and antimicrobial mixture (potassium sorbate-sodium benzoate) impact on the stability of a tamarillo (Cyphomandra betacea) sweet product preserved by hurdle technology.

PubMed

Preciado-Iñiga, Grace E; Amador-Espejo, Genaro G; Bárcenas, María E

2018-02-01

In a previous study, a stable tamarillo sweet product (TSP) was obtained by applying hurdle technology (low pH, reduction of water activity, sodium benzoate addition and stored at 4 °C, with oxygen and light protection). In order to improve the TSP shelf life, it was decided to employ a mixture of antimicrobial agents (sodium benzoate and potassium sorbate 50-50%) and fruit blanching. The phenolic compounds content, total monomeric anthocyanins of TSP, antioxidant capacity, microbial growth (aerobic mesophilic bacteria, molds and yeasts) and net color change were evaluated, during 63 days. The results showed that the use of blanched tamarillo and the addition of the antimicrobial mixture increased the TSP stability, in which the microbial counts were maintained below the limits established by the official food safety norms, without effects the antioxidant compounds and color.

Covalent Bonding of Chlorogenic Acid Induces Structural Modifications on Sunflower Proteins.

PubMed

Karefyllakis, Dimitris; Salakou, Stavroula; Bitter, J Harry; van der Goot, Atze J; Nikiforidis, Constantinos V

2018-02-19

Proteins and phenols coexist in the confined space of plant cells leading to reactions between them, which result in new covalently bonded complex molecules. This kind of reactions has been widely observed during storage and processing of plant materials. However, the nature of the new complex molecules and their physicochemical properties are largely unknown. Therefore, we investigated the structural characteristics of covalently bonded complexes between sunflower protein isolate (SFPI, protein content 85 wt %) and the dominant phenol in the confined space of a sunflower seed cell (chlorogenic acid, CGA). It was shown that the efficiency of bond formation goes through a maximum as a function of the SFPI:CGA ratio. Moreover, the bonding of CGA with proteins resulted in changes in the secondary and tertiary structure of the protein. It was also shown that the phenol bound strongly to the protein, which resulted in new crosslinks between the polypeptide chains. As a result, secondary structures like α-helices and β-sheets diminished, which in turn resulted in more disordered domains and a subsequent modification of the tertiary structure of the proteins. These findings are relevant for establishing future protocols for extraction of high-quality proteins and phenols when utilizing plant material and offer insight into the impact of processing that these ingredients endure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proton-Coupled Electron Transfer in a Strongly Coupled Photosystem II-Inspired Chromophore–Imidazole–Phenol Complex: Stepwise Oxidation and Concerted Reduction

DOE PAGES

Manbeck, Gerald F.; Fujita, Etsuko; Concepcion, Javier J.

2016-08-18

Proton-coupled electron-transfer (PCET) reactions were studied in acetonitrile for a Photosystem II (PSII) inspired [Ru(bpy) 2(phen-imidazole-Ph(OH)( tBu) 2)] 2+, in which Ru(III) generated by a flash-quench sequence oxidizes the appended phenol and the proton is transferred to the hydrogen bonded imidazole base. In contrast to related systems, the donor and acceptor are strongly coupled, as indicated by the shift in the Ru III/IIcouple upon phenol oxidation, and intramolecular oxidation of the phenol by Ru(III) is energetically favorable by both stepwise or concerted pathways. The phenol oxidation occurs via a stepwise ET-PT mechanism with k ET = 2.7 × 10 7more » s ₋1 and a kinetic isotope effect (KIE) of 0.99 ± 0.03. The electron transfer reaction was characterized as adiabatic with λ DA = 1.16 eV and 280 < H DA < 540 cm ₋1 consistent with strong electronic coupling and slow solvent dynamics. Reduction of the phenoxyl radical by the quencher radical was examined as the analogue of the redox reaction between the PSII tyrosyl radical and the oxygen evolving complex (OEC). In our PSII-inspired complex, the recombination reaction activation energy is < 2 kcal mol ₋1. In conclusion, the reaction is nonadiabatic (V PCET ~ 22 cm ₋1 (H) and 49 cm ₋1 (D)), concerted, and exhibits an unexpected inverse KIE of 0.55 that is attributed to greater overlap of the reactant vibronic ground state with the OD vibronic states of the proton acceptor due to the smaller quantum spacing of the deuterium vibrational levels.« less

Analysis of a whole diet in terms of phenolic content and antioxidant capacity: effects of a simulated gastrointestinal digestion.

PubMed

Koehnlein, Eloá Angélica; Koehnlein, Érica Marcela; Corrêa, Rúbia Carvalho Gomes; Nishida, Verônica Sayuri; Correa, Vanesa Gesser; Bracht, Adelar; Peralta, Rosane Marina

2016-09-01

This work compares the phenolic contents and the total antioxidant capacity of the 36 most popular Brazilian foods submitted to aqueous extraction or in vitro digestion. The purpose was to evaluate the extent by which digestion differs from the simple aqueous extraction procedures of several food matrices. After in vitro digestion, cereals, legumes, vegetables, tuberous vegetables, chocolates and fruits showed higher phenolic contents and higher antioxidant activities than those obtained by aqueous extraction. Contrarily, the digestion caused a reduction in the phenolic contents and antioxidant activities of beverages (red wine, coffee and yerba mate). Our results suggest that the phenolics of food groups with solid and complex matrix are protected against enzymatic action and alteration in pH during the digestion, what does not occur in liquid food matrices such as the beverages. This fact would overestimate the antioxidant activities of beverages submitted solely to aqueous extraction.

Application of Biologically-Based Lumping To Investigate the Toxicological Interactions of a Complex Gasoline Mixture

EPA Science Inventory

People are often exposed to complex mixtures of environmental chemicals such as gasoline, tobacco smoke, water contaminants, or food additives. However, investigators have often considered complex mixtures as one lumped entity. Valuable information can be obtained from these exp...

Steam injection pressing : large panel fabrication with southern hardwoods

Treesearch

Robert L. Geimer; Eddie W. Price

1986-01-01

Large 4 by 8 ft (1.22 by 2.44 m) panels were made using a steam injection method of pressing. Homogenously constructed flakeboards were fabricated from southern red oak, sweet gum, and a mixture of the two species using both isocyanate and phenolic resins. Isocyanate was especially suited to the process and 1-1/2 in. (38 mm) thick panels were pressed in less than 150...

Coupled Electrokinetics-Adsorption Technique for Simultaneous Removal of Heavy Metals and Organics from Saline-Sodic Soil

PubMed Central

Lukman, Salihu; Essa, Mohammed Hussain; Mu'azu, Nuhu Dalhat; Bukhari, Alaadin

2013-01-01

In situ remediation technologies for contaminated soils are faced with significant technical challenges when the contaminated soil has low permeability. Popular traditional technologies are rendered ineffective due to the difficulty encountered in accessing the contaminants as well as when employed in settings where the soil contains mixed contaminants such as petroleum hydrocarbons, heavy metals, and polar organics. In this study, an integrated in situ remediation technique that couples electrokinetics with adsorption, using locally produced granular activated carbon from date palm pits in the treatment zones that are installed directly to bracket the contaminated soils at bench-scale, is investigated. Natural saline-sodic soil, spiked with contaminant mixture (kerosene, phenol, Cr, Cd, Cu, Zn, Pb, and Hg), was used in this study to investigate the efficiency of contaminant removal. For the 21-day period of continuous electrokinetics-adsorption experimental run, efficiency for the removal of Zn, Pb, Cu, Cd, Cr, Hg, phenol, and kerosene was found to reach 26.8, 55.8, 41.0, 34.4, 75.9, 92.49, 100.0, and 49.8%, respectively. The results obtained suggest that integrating adsorption into electrokinetic technology is a promising solution for removal of contaminant mixture from saline-sodic soils. PMID:24235885

Pharmacological and phytochemical screening of Palestinian traditional medicinal plants Erodium laciniatum and Lactuca orientalis.

PubMed

Jaradat, Nidal; AlMasri, Motasem; Zaid, Abdel Naser; Othman, Dua'a Ghazi

2017-09-01

Various epidemiological studies showed that herbal remedies containing polyphenols may protect against various diseases such as cancers, vascular diseases and inflammatory pathologies. Currently, such groups of bioactive compounds have become a subject of many antimicrobials and antioxidant investigations. Accordingly, the current study aimed to conduct biological and phytochemical screening for two Palestinian traditional medicinal plants, Erodium laciniatum and Lactuca orientalis. Current plants phytoconstituents and their antioxidant activities were evaluated by using standard phytochemical methods; meanwhile, antimicrobial activities were estimated by using several types of American Type Culture Collection and multidrug resistant clinical isolates by using agar diffusion well-variant, agar diffusion disc-variant and broth microdilution methods. Phytochemical screenings showed that L. orientalis and E. laciniatum contain mixtures of secondary and primary metabolites Moreover, total flavonoid, tannins and phenols content in E. laciniatum extract were higher than the L. orientalis extracts with almost the same antioxidant potentials. Additionally, both plants organic and aqueous extracts showed various potentials of antimicrobial activity Conclusions: Overall, the studied species have a mixture of phytochemicals, flavonoids, phenols and tannins also have antioxidant and antimicrobial activities which approved their folk uses in treatments of infectious and Alzheimer diseases and simultaneously can be used as therapeutic agents in the pharmaceutical industries.

CEC with new monolithic stationary phase based on a fluorinated monomer, trifluoroethyl methacrylate.

PubMed

Yurtsever, Arda; Saraçoğlu, Berna; Tuncel, Ali

2009-02-01

A new, fluorinated monolithic stationary phase for CEC was first synthesized by a single-stage, thermally initiated copolymerization of a fluorinated monomer, 2,2,2-trifluoroethyl methacrylate (TFEM) and ethylene dimethacrylate (EDMA) in the presence of a porogen mixture. In this preparation, 2-acrylamido-2-methyl-1-propanesulfonic acid was used as the charge-bearing monomer. The porogen mixture was prepared by mixing isoamylalcohol and 1,4-butanediol. A clear increase in the electroosmotic mobility was observed with increasing pH. The electroosmotic mobility decreased with increasing ACN concentration. Poly(TFEM-co-EDMA) monolith prepared under optimized polymerization conditions was successfully used in the separation of alkylbenzenes and phenols by CEC. The best chromatographic separation for alkylbenzenes was performed with lower ACN concentrations (i.e. 60% v/v) with respect to the common acrylic-based CEC monoliths. The theoretical plate numbers up to 220 000 plates/m were achieved in the reversed phase separation of phenols. Poly(TFEM-co-EDMA) monolith also allowed the simultaneous separation of aniline and benzoic acid derivatives by a single run and by using a lower ACN concentration in the mobile phase with respect to the similar electrochromatographic separations. A stable retention behaviour in reversed phase separation of alkylbenzenes was obtained with the poly(TFEM-co-EDMA) monolith.

Highly galloylated tannin fractions from witch hazel (Hamamelis virginiana) bark: electron transfer capacity, in vitro antioxidant activity, and effects on skin-related cells.

PubMed

Touriño, Sonia; Lizárraga, Daneida; Carreras, Anna; Lorenzo, Sonia; Ugartondo, Vanessa; Mitjans, Montserrat; Vinardell, María Pilar; Juliá, Luis; Cascante, Marta; Torres, Josep Lluís

2008-03-01

Witch hazel ( Hammamelis virginiana) bark is a rich source of both condensed and hydrolizable oligomeric tannins. From a polyphenolic extract soluble in both ethyl acetate and water, we have generated fractions rich in pyrogallol-containing polyphenols (proanthocyanidins, gallotannins, and gallates). The mixtures were highly active as free radical scavengers against ABTS, DPPH (hydrogen donation and electron transfer), and HNTTM (electron transfer). They were also able to reduce the newly introduced TNPTM radical, meaning that they included some highly reactive components. Witch hazel phenolics protected red blood cells from free radical-induced hemolysis and were mildly cytotoxic to 3T3 fibroblasts and HaCat keratinocytes. They also inhibited the proliferation of tumoral SK-Mel 28 melanoma cells at lower concentrations than grape and pine procyanidins. The high content in pyrogallol moieties may be behind the effect of witch hazel phenolics on skin cells. Because the most cytotoxic and antiproliferative mixtures were also the most efficient as electron transfer agents, we hypothesize that the final putative antioxidant effect of polyphenols may be in part attributed to the stimulation of defense systems by mild prooxidant challenges provided by reactive oxygen species generated through redox cycling.

Naturally occurring phenolic acids modulate TPA-induced activation of EGFR, AP-1, and STATs in mouse epidermis.

PubMed

Cichocki, Michał; Dałek, Miłosz; Szamałek, Mateusz; Baer-Dubowska, Wanda

2014-01-01

Epidermal growth factor receptor (EGFR) plays an important role in epithelial carcinogenesis and appears to be involved in STATs activation. In this study we investigated the possible interference of naturally occurring phenolic acids with EGFR, activator protein-1 (AP-1), and signal transducers and activators of transcription (STATs) pathways activated by topical application of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Balb/c mice epidermis. Pretreatment with tannic or chlorogenic acid resulted in a significant decrease in the phosphorylation of EGFR Y-1068 and Y-1173 tyrosine residues, which was accompanied by reduced activation of AP-1. Tannic acid decreased also the c-Jun AP-1 subunit level and binding to TPA response element (TRE) (3- and 2-fold in comparison with TPA-treated group respectively). Simultaneous reduction of JNK activity might be responsible for reduced activation of AP-1. In contrast to these more complex phenolics, protocatechuic acid increased the activity of JNK and was also the most efficient inhibitor of STATs activation. These results indicate that naturally occurring phenolic acids, by decreasing EGFR, AP-1, and STATs activation, may modulate other elements both upstream and downstream in these pathways and thus inhibit the tumor development. Although more complex phenolics affect mainly the EGFR/AP-1 pathway, STATs seem to be the most important targets for simple compounds, such as protocatechuic acid.

Toxicity of a hazardous chemical mixture in the planarian, Dugesia dorotocephala

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramsdell, H.S.; Matthews, C.M.

1995-12-31

The responses of the planarian, Dugesia dorotocephala to toxic chemical mixtures representative of water contaminants associated with hazardous waste sites have been studied in laboratory experiments. These free-living flatworms are readily maintained under laboratory conditions and are a useful invertebrate model for toxicology studies. Their widespread occurrence also makes them potentially useful for environmental studies. Mature asexual Dugesia dorotocephala were exposed for 14 days to mixtures of seven contaminants frequently detected in water at hazardous waste sites. The complete 1X mixture contained both metals (As, 3.1 ppm; Cr, 0.7 ppm; Pb, 3.7 ppm) and organics (chloroform, 1.5 ppm; benzene, 5.0more » ppm; phenol, 3.4 ppm; trichloroethylene, 3.8 ppm). Groups of planaria were treated with the complete mixture at 0.1X, 1X and 10X concentrations. Additional groups were exposed to the metals-only or organics-only submixtures, also at 0.1X, 1X and 10X concentrations. Treatment solutions were renewed daily. Suppression of fissioning was observed in all of the 1X and 10X treatment groups. Significant mortality occurred only in the 10X complete and 1 0X metals-only treatments. It appears that the toxic effects of the complete mixture are primarily associated with the metal components.« less

COMPARATIVE TUMOR-INITIATING ACTIVITY OF COMPLEX MIXTURES FROM ENVIRONMENTAL PARTICULATE EMISSIONS ON SENCAR MOUSE SKIN

EPA Science Inventory

The value of the SENCAR mouse for testing tumorigenic properties of complex mixtures on mouse skin was studied. Seven complex mixtures were obtained as dichloromethane extracts of collected particulate emissions from three diesel-fueled automobiles, a heavy-duty diesel engine, a ...

Phenolic composition, antioxidant capacity and antibacterial activity of selected Irish Brassica vegetables.

PubMed

Jaiswal, Amit Kumar; Rajauria, Gaurav; Abu-Ghannam, Nissreen; Gupta, Shilpi

2011-09-01

Vegetables belonging to the Brassicaceae family are rich in polyphenols, flavonoids and glucosinolates, and their hydrolysis products, which may have antibacterial, antioxidant and anticancer properties. In the present study, phenolic composition, antibacterial activity and antioxidant capacity of selected Brassica vegetables, including York cabbage, Brussels sprouts, broccoli and white cabbage were evaluated after extraction with aqueous methanol. Results obtained showed that York cabbage extract had the highest total phenolic content, which was 33.5, followed by 23.6, 20.4 and 18.4 mg GAE/g of dried weight (dw) of the extracts for broccoli, Brussels sprouts and white cabbage, respectively. All the vegetable extracts had high flavonoid contents in the order of 21.7, 17.5, 15.4 and 8.75 mg QE/g of extract (dw) for York cabbage, broccoli, Brussels sprouts and white cabbage, respectively. HPLC-DAD analysis showed that different vegetables contain a mixture of distinct groups of phenolic compounds. All the extracts studied showed a rapid and concentration dependent antioxidant capacity in diverse antioxidant systems. The antibacterial activity was determined against Gram-positive and Gram-negative bacteria. York cabbage extract exhibited significantly higher antibacterial activity against Listeria monocytogenes (100%) and Salmonella abony (94.3%), being the most susceptible at a concentration of 2.8%, whereas broccoli, Brussels sprouts and white cabbage had moderate to weak activity against all the test organisms. Good correlation (r2 0.97) was found between total phenolic content obtained by spectrophotometric analysis and the sum of the individual polyphenols monitored by HPLC-DAD.

Ferricyanide-based analysis of aqueous lignin suspension revealed sequestration of water-soluble lignin moieties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshua, C. J.; Simmons, B. A.; Singer, S. W.

This study describes the application of a ferricyanide-based assay as a simple and inexpensive assay for rapid analysis of aqueous lignin samples. The assay measures the formation of Prussian blue from the redox reaction between a mixture of potassium ferricyanide and ferric chloride, and phenolic hydroxyl groups of lignin or lignin-derived phenolic moieties. This study revealed that soluble lignin moieties exhibited stronger ferricyanide reactivity than insoluble aggregates. The soluble lignin moieties exhibited higher ferricyanide reactivity because of increased access of the phenolic hydroxyl groups to the ferricyanide reagents. Ferricyanide reactivity of soluble lignin moieties correlated inversely with the molecular weightmore » distributions of the molecules, probably due to the involvement of phenolic hydroxyl groups in bond formation. The insoluble lignin aggregates exhibited low ferricyanide reactivity due to sequestration of the phenolic hydroxyl groups within the solid matrix. The study also highlighted the sequestration of polydispersed water-soluble lignin moieties by insoluble aggregates. The sequestered moieties were released by treatment with 0.01 M NaOH at 37 °C for 180 min. The redox assay was effective on different types of lignin extracts such as Klason lignin from switchgrass, ionic-liquid derived lignin from Eucalyptus and alkali lignin extracts. The assay generated a distinct profile for each lignin sample that was highly reproducible. The assay was also used to monitor consumption of syringic acid by Sphingobium sp. SYK-6. The simplicity and reproducibility of this assay makes it an excellent and versatile tool for qualitative and semi-quantitative characterization and comparative profiling of aqueous lignin samples.« less

Spice phenolics inhibit human PMNL 5-lipoxygenase.

PubMed

Prasad, N Satya; Raghavendra, R; Lokesh, B R; Naidu, K Akhilender

2004-06-01

A wide variety of phenolic compounds and flavonoids present in spices possess potent antioxidant, antimutagenic and anticarcinogenic activities. We examined whether 5-lipoxygenase (5-LO), the key enzyme involved in biosynthesis of leukotrienes is a possible target for the spices. Effect of aqueous extracts of turmeric, cloves, pepper, chili, cinnamon, onion and also their respective active principles viz., curcumin, eugenol, piperine, capsaicin, cinnamaldehyde, quercetin, and allyl sulfide were tested on human PMNL 5-LO activity by spectrophotomeric and HPLC methods. The formation of 5-LO product 5-HETE was significantly inhibited in a concentration-dependent manner with IC(50) values of 0.122-1.44 mg for aqueous extracts of spices and 25-83 microM for active principles, respectively. The order of inhibitory activity was of quercetin>eugenol>curcumin>cinnamaldehyde>piperine>capsaicin>allyl sulfide. Quercetin, eugenol and curcumin with one or more phenolic ring and methoxy groups in their structure showed high inhibitory effect, while the non-phenolic spice principle allyl sulfide showed least inhibitory effect on 5-LO. The inhibitory effect of quercetin, curcumin and eugenol was similar to that of synthetic 5-LO inhibitors-phenidone and NDGA. Moreover, the inhibitory potency of aqueous extracts of spice correlated with the active principles of their respective spices. The synergistic or antagonistic effect of mixtures of spice active principles and spice extracts were investigated and all the combinations of spice active principles/extracts exerted synergistic effect in inhibiting 5-LO activity. These findings clearly suggest that phenolic compounds present in spices might have physiological role in modulating 5-LO pathway.

Intestinal absorption of hawthorn flavonoids--in vitro, in situ and in vivo correlations.

PubMed

Zuo, Zhong; Zhang, Li; Zhou, Limin; Chang, Qi; Chow, Moses

2006-11-25

Our previous studies identified hyperoside (HP), isoquercitrin (IQ) and epicatechin (EC) to be the major active flavonoid components of the hawthorn phenolic extract from hawthorn fruits demonstrating inhibitory effect on in vitro Cu(+2)-mediated low density lipoproteins oxidation. Among these three hawthorn flavonoids, EC was the only one detectable in plasma after the oral administration of hawthorn phenolic extract to rats. The present study aims to investigate the intestinal absorption mechanisms of these three hawthorn flavonoids by in vitro Caco-2 monolayer model, rat in situ intestinal perfusion model and in vivo pharmacokinetics studies in rats. In addition, in order to investigate the effect of the co-occurring components in hawthorn phenolic extract on the intestinal absorption of these three major hawthorn flavonoids, intestinal absorption transport profiles of HP, IQ and EC in forms of individual pure compound, mixture of pure compounds and hawthorn phenolic extract were studied and compared. The observations from in vitro Caco-2 monolayer model and in situ intestinal perfusion model indicated that all three studied hawthorn flavonoids have quite limited permeabilities. EC and IQ demonstrated more extensive metabolism in the rat in situ intestinal perfusion model and in vivo study than in Caco-2 monolayer model. Moreover, results from the Caco-2 monolayer model, rat in situ intestinal perfusion model as well as the in vivo pharmacokinetics studies in rats consistently showed that the co-occurring components in hawthorn phenolic extract might not have significant effect on the intestinal absorption of the three major hawthorn flavonoids studied.

Ferricyanide-based analysis of aqueous lignin suspension revealed sequestration of water-soluble lignin moieties

DOE PAGES

Joshua, C. J.; Simmons, B. A.; Singer, S. W.

2016-06-02

This study describes the application of a ferricyanide-based assay as a simple and inexpensive assay for rapid analysis of aqueous lignin samples. The assay measures the formation of Prussian blue from the redox reaction between a mixture of potassium ferricyanide and ferric chloride, and phenolic hydroxyl groups of lignin or lignin-derived phenolic moieties. This study revealed that soluble lignin moieties exhibited stronger ferricyanide reactivity than insoluble aggregates. The soluble lignin moieties exhibited higher ferricyanide reactivity because of increased access of the phenolic hydroxyl groups to the ferricyanide reagents. Ferricyanide reactivity of soluble lignin moieties correlated inversely with the molecular weightmore » distributions of the molecules, probably due to the involvement of phenolic hydroxyl groups in bond formation. The insoluble lignin aggregates exhibited low ferricyanide reactivity due to sequestration of the phenolic hydroxyl groups within the solid matrix. The study also highlighted the sequestration of polydispersed water-soluble lignin moieties by insoluble aggregates. The sequestered moieties were released by treatment with 0.01 M NaOH at 37 °C for 180 min. The redox assay was effective on different types of lignin extracts such as Klason lignin from switchgrass, ionic-liquid derived lignin from Eucalyptus and alkali lignin extracts. The assay generated a distinct profile for each lignin sample that was highly reproducible. The assay was also used to monitor consumption of syringic acid by Sphingobium sp. SYK-6. The simplicity and reproducibility of this assay makes it an excellent and versatile tool for qualitative and semi-quantitative characterization and comparative profiling of aqueous lignin samples.« less

Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods - slides

EPA Science Inventory

Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods

EPA Science Inventory

Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

Synthesis and spectroscopic studies on the new Schiff base derived from the 1:2 condensation of 2,6-diformyl-4-methylphenol with 5-aminouracil (BDF5AU) and its transition metal complexes. Influence on biologically active peptides-regulating aminopeptidases.

PubMed

Hueso-Ureña, Francisco; Illán-Cabeza, Nuria A; Moreno-Carretero, Miguel N; Martínez-Martos, José M; Ramírez-Expósito, María J

2003-04-01

The synthesis, spectroscopic (IR, 1H and 13C NMR, UV-Vis-NIR, EPR), magnetic measurements and biological studies of a number of complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Au(III) and Hg(II) of the Schiff base derived from the 1:2 condensation of 2,6-diformyl-4-methylphenol and 5-aminouracil, ((5-[[(3-[[(2,4-dioxopyrimidin-5(1H,3H)-yl)imino]methyl]-2-hydroxy-5-methylphenyl)methylene]amino]pyrimidine-2,4(1H,3H)-dione, hereafter denoted as BDF5AU) are reported. In all cases, the complexes appear to be monomeric. The deprotonated ligand in the phenolic oxygen atom shows a tridentate coordination mode through the two azomethine nitrogen atoms and the phenolic oxygen atom. The coordination of the neutral ligand takes place through the phenolic oxygen atom and one azomethine nitrogen atom and the carbonylic oxygen atom in fourth position of one uracil ring. The biological properties of some perchlorate complexes on the activity of some neutral, acid, basic and omega aminopeptidases (AP) are assayed, demonstrating a general inhibitory effect. Neutral and basic AP are mainly inhibited by Cu(II), Ni(II) and Cd(II) complexes, although tyrosyl-AP is activated by Zn(II) complex. Glutamyl-AP but not aspartyl-AP is inhibited by all the complexes assayed excepting Zn(II) complex. Finally, omega AP is inhibited by Ni(II) and Cd(II) complexes. Copyright 2003 Elsevier Science Inc.

Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

PubMed

Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

2013-01-01

The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

High-resolution liquid chromatography/electrospray ionization time-of-flight mass spectrometry combined with liquid chromatography/electrospray ionization tandem mass spectrometry to identify polyphenols from grape antioxidant dietary fiber.

PubMed

Touriño, Sonia; Fuguet, Elisabet; Jáuregui, Olga; Saura-Calixto, Fulgencio; Cascante, Marta; Torres, Josep Lluís

2008-11-01

Grape antioxidant dietary fiber (GADF) is a dietary supplement that combines the benefits of both fiber and antioxidants that help prevent cancer and cardiovascular diseases. The antioxidant polyphenolic components in GADF probably help prevent cancer in the digestive tract, where they are bioavailable. Mass spectrometry coupled to liquid chromatography is a powerful tool for the analysis of complex plant derivatives such as GADF. We use a combination of MS techniques, namely liquid chromatography/electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOF-MS) and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) on a triple quadrupole, for the identification of the polyphenolic constituents of the soluble fraction of GADF. First, we separated the mixture into four fractions which were tested for phenolic constituents using the TOF system in the full scan mode. The high sensitivity and resolution of the TOF detector over the triple quadrupole facilitate the preliminary characterization of the fractions. Then we used LC/ESI-MS/MS to identify the individual phenols through MS/MS experiments (product ion scan, neutral loss scan, precursor ion scan). Finally, most of the identities were unequivocally confirmed by accurate mass measurements on the TOF spectrometer. LC/ESI-TOF-MS combined with MS/MS correctly identifies the bioactive polyphenolic components from the soluble fraction of GADF. High-resolution TOF-MS is particularly useful for identifying the structure of compounds with the same LC/ESI-MS/MS fragmentation patterns.

Structure-affinity relationship of the interaction between phenolic acids and their derivatives and β-lactoglobulin and effect on antioxidant activity.

PubMed

Wu, Simin; Zhang, Yunyue; Ren, Fazheng; Qin, Yinghui; Liu, Jiaxin; Liu, Jingwen; Wang, Qingyu; Zhang, Hao

2018-04-15

In this study, 71 phenolic acids and their derivatives were used to investigate the structure-affinity relationship of β-lactoglobulin binding, and the effect of this interaction on antioxidant activity. Based on a fluorescence quenching method, an improved mathematical model was adopted to calculate the binding constants, with a correction for the inner-filter effect. Hydroxylation at the 3-position increased the affinity of the phenolic acids for β-lactoglobulin, while hydroxylation at the 2- or 4-positions had a negative effect. Complete methylation of all hydroxy groups, except at the 3-position, enhanced the binding affinity. Replacing the hydroxy groups with methyl groups at the 2-position also had a positive effect. Hydrogen bonding was one of the binding forces for the interaction. The antioxidant activity of phenolic acid-β-lactoglobulin complexes was higher than that of phenolic acids alone. These findings provide an understanding of the structure-activity relationship of the interaction between β-lactoglobulin and phenolic acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Potent Staphylococcus Aureus Growth Inhibitor Of A Dried Flower Extract Of Pinus Merkusii Jungh & De Vriese And Copper Nanoparticle

NASA Astrophysics Data System (ADS)

Masruri, Masruri; Norani Pangestin, Dinna; Mariyah Ulfa, Siti; Riyanto, Slamet; Srihardyastutie, Arie; Farid Rahman, Moh.

2018-01-01

The paper report antibacterial activity of flower extract from Pinus merkusii Jungh Et De Vriese and its mixture with copper nanoparticle on Staphylococcus aureus. This finding revealed the potency of pine forestry waste to overcome a bacterial-resistance problem on some commercially antibiotics. The extract was prepared by hot water extraction of a dried powder of pine flower. Copper nanoparticle was synthesized following “green synthesis technique” using phenolic-rich extract of pine’s flower as a reduction and capping agent. In short, a mixture of pine’s flower extract and copper nanoparticle importantly was able to inhibit the growth of Staphylococcus aureus four times higher than that using water extract.

Honeybees Learn Odour Mixtures via a Selection of Key Odorants

PubMed Central

Reinhard, Judith; Sinclair, Michael; Srinivasan, Mandyam V.; Claudianos, Charles

2010-01-01

Background The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures. Methodology/Principal Findings This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants. Conclusions/Significance Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees. PMID:20161714

Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

PubMed

Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

2013-01-14

A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

Applicability study of classical and contemporary models for effective complex permittivity of metal powders.

PubMed

Kiley, Erin M; Yakovlev, Vadim V; Ishizaki, Kotaro; Vaucher, Sebastien

2012-01-01

Microwave thermal processing of metal powders has recently been a topic of a substantial interest; however, experimental data on the physical properties of mixtures involving metal particles are often unavailable. In this paper, we perform a systematic analysis of classical and contemporary models of complex permittivity of mixtures and discuss the use of these models for determining effective permittivity of dielectric matrices with metal inclusions. Results from various mixture and core-shell mixture models are compared to experimental data for a titanium/stearic acid mixture and a boron nitride/graphite mixture (both obtained through the original measurements), and for a tungsten/Teflon mixture (from literature). We find that for certain experiments, the average error in determining the effective complex permittivity using Lichtenecker's, Maxwell Garnett's, Bruggeman's, Buchelnikov's, and Ignatenko's models is about 10%. This suggests that, for multiphysics computer models describing the processing of metal powder in the full temperature range, input data on effective complex permittivity obtained from direct measurement has, up to now, no substitute.

The Thermal Decomposition of Some Organic Lead Compounds

DTIC Science & Technology

1957-11-01

either of salicylic anhydride or of its pyrolysis fragments which are reported to be a mixture of carbon dioxide , phenol and phenyl salicylate. Other...7) have studied the decomposition of the mono-salicylate in vacuo at 400°C. and have found that one molecule of carbon dioxide is evolved per...of lead nitrate and nitrosalicylic acid, though seme of the latter is decarboxylated with evolution of carbon dioxide . These points are considered

Investigation of thermal and optical properties of some quartet mixed hydrogen-bonded liquid crystals

NASA Astrophysics Data System (ADS)

Okumuş, Mustafa

2017-11-01

In this study, the thermal and optical properties of quartet mixtures formed at different weight ratios (1:1:1:1 and 1.5:1:1:1) from liquid crystals 4-octyloxy-4‧-cyanobiphenyl (8OCB), 4-hexylbenzoic acid, 4-(octyloxy)benzoic acid and 4-(decyloxy)benzoic acid were investigated by differential scanning calorimeter (DSC) and polarized optic microscopy (POM). The phase transition temperatures of the novel quartet mixtures measured in the DSC experiments are in line with the POM experiments. The experimental results clearly show that the novel liquid crystal mixtures have displayed pure liquid crystalline properties. According to the phase diagram drawn from DSC results, the nematic range of the novel mixture at the eutectic point is larger than the nematic ranges of the components. The mesomorphic structures of produced homolog complex mixtures are found to be smectic and nematic phases. But the smectic phase cannot be observed in the novel complex 1.5:1:1:1 mixture during continuous cooling. The nematic range of the novel complex 1.5:1:1:1 mixture is bigger than the nematic range of the novel complex 1:1:1:1 mixture with increasing 8OCB. Also, the nematic-to-isotropic phase transition temperature decreases with increasing the weight ratio of 8OCB in the complex quartet mixture. Another interesting result is that the produced mixtures are to be like a medical cream at room temperatures. Furthermore, order parameter and thermal stability factor of the transitions are also calculated.

Evaluating the aquatic toxicity of complex organic chemical mixtures: lessons learned from polycyclic aromatic hydrocarbon and petroleum hydrocarbon case studies.

PubMed

Landrum, Peter F; Chapman, Peter M; Neff, Jerry; Page, David S

2012-04-01

Experimental designs for evaluating complex mixture toxicity in aquatic environments can be highly variable and, if not appropriate, can produce and have produced data that are difficult or impossible to interpret accurately. We build on and synthesize recent critical reviews of mixture toxicity using lessons learned from 4 case studies, ranging from binary to more complex mixtures of primarily polycyclic aromatic hydrocarbons and petroleum hydrocarbons, to provide guidance for evaluating the aquatic toxicity of complex mixtures of organic chemicals. Two fundamental requirements include establishing a dose-response relationship and determining the causative agent (or agents) of any observed toxicity. Meeting these 2 requirements involves ensuring appropriate exposure conditions and measurement endpoints, considering modifying factors (e.g., test conditions, test organism life stages and feeding behavior, chemical transformations, mixture dilutions, sorbing phases), and correctly interpreting dose-response relationships. Specific recommendations are provided. Copyright © 2011 SETAC.

Antitussive, expectorant, and anti-inflammatory activities of four caffeoylquinic acids isolated from Tussilago farfara.

PubMed

Wu, Qi-Zhen; Zhao, Dong-Xia; Xiang, Juan; Zhang, Mian; Zhang, Chao-Feng; Xu, Xiang-Hong

2016-07-01

The flower bud of Tussilago farfara L. (Compositae) (FTF) is one of the traditional Chinese medicinal herbs used to treat cough, phlegm, bronchitic, and asthmatic conditions. The objective of this study is to isolate four caffeoylquinic acids from the ethyl acetate extract (EtE) of FTF and to evaluate their antitussive, expectorant, and anti-inflammatory activities. The structures of compounds 1-4 isolated from EtE were determined by spectral analysis. Mice were orally treated with these compounds and their mixture (in a ratio of 5:28:41:26 as in EtE) at doses of 10 and 20 mg/kg once daily for 3 d. The antitussive and expectorant activities were evaluated separately with the ammonia liquor-induced model and the phenol red secretion model. The anti-inflammation activity was evaluated using leukocyte count in the bronchoalveolar lavage fluid after ammonia liquor-induced acute airway inflammation. The four compounds were identified as chlorogenic acid (1), 3,5-dicaffeoylquinic acid (2), 3,4-dicaffeoylquinic acid (3), and 4,5-dicaffeoylquinic acid (4). All compounds, especially compound 4 (58.0% inhibition in cough frequency), showed a significant antitussive effect. However, the mixture was the most effective to inhibit the cough frequency by 61.7%. All compounds also showed a significant expectorant effect, while compound 2 was the most potent to enhance the phenol red secretion by 35.7%. All compounds significantly alleviated inflammation, but compound 4 showed the strongest effect to inhibit the leukocytosis by 49.7%. The caffeoylquinic acids and their mixture, exhibiting significant antitussive, expectorant, and anti-inflammatory effects, could be considered as the main effective ingredients of FTF, and they may act in a collective and synergistic way.

Magnetic nanoparticle-mediated isolation of functional bacteria in a complex microbial community

PubMed Central

Zhang, Dayi; Berry, James P; Zhu, Di; Wang, Yun; Chen, Yin; Jiang, Bo; Huang, Shi; Langford, Harry; Li, Guanghe; Davison, Paul A; Xu, Jian; Aries, Eric; Huang, Wei E

2015-01-01

Although uncultured microorganisms have important roles in ecosystems, their ecophysiology in situ remains elusive owing to the difficulty of obtaining live cells from their natural habitats. In this study, we employed a novel magnetic nanoparticle-mediated isolation (MMI) method to recover metabolically active cells of a group of previously uncultured phenol degraders, Burkholderiales spp., from coking plant wastewater biosludge; five other culturable phenol degraders—Rhodococcus sp., Chryseobacterium sp. and three different Pseudomonas spp.—were also isolated from the same biosludge using traditional methods. The kinetics of phenol degradation by MMI-recovered cells (MRCs) was similar to that of the original sludge. Stable isotope probing (SIP) and pyrosequencing of the 16S rRNA from the ‘heavy' DNA (13C-DNA) fractions indicated that Burkholderiales spp. were the key phenol degraders in situ in the biosludge, consistent with the results of MRCs. Single-cell Raman micro-spectroscopy was applied to probe individual bacteria in the MRCs obtained from the SIP experiment and showed that 79% of them were fully 13C-labelled. Biolog assays on the MRCs revealed the impact of various carbon and nitrogen substrates on the efficiency of phenol degradation in the wastewater treatment plant biosludge. Specifically, hydroxylamine, a metabolite of ammonia oxidisation, but not nitrite, nitrate or ammonia, inhibited phenol degradation in the biosludge. Our results provided a novel insight into the occasional abrupt failure events that occur in the wastewater treatment plant. This study demonstrated that MMI is a powerful tool to recover live and functional cells in situ from a complex microbial community to enable further characterisation of their physiology. PMID:25191996

The influence of beverage composition on delivery of phenolic compounds from coffee and tea.

PubMed

Ferruzzi, Mario G

2010-04-26

Epidemiological data suggest that consumption of coffee and tea is associated with a reduced risk of several chronic and degenerative diseases including cardiovascular disorders, diabetes, obesity and neurodegenerative disorders. Both coffee and tea are a rich source of phenolic compounds including chlorogenic acids in coffee; and flavan-3-ols as well as complex theaflavins and thearubigens in tea. Coffee and tea are two of the most commonly consumed beverages in the world and thus represent a significant opportunity to positively affect disease risk and outcomes globally. Central to this opportunity is a need to better understand factors that may affect the bioavailability of specific phenolic components from coffee and tea based beverages. An overview of the phenolic composition of coffee and tea is discussed in the context of how processing and composition might influence phenolic profiles and bioavailability of individual phenolic components. Specifically, the impact of beverage formulation, the extent and type of processing and the influence of digestion on stability, bioavailability and metabolism of bioactive phenolics from tea and coffee are discussed. The impact of co-formulation with ascorbic acid and other phytochemicals are discussed as strategies to improve absorption of these health promoting phytochemicals. A better understanding of how the beverage composition impacts phenolic profiles and their bioavailability is critical to development of beverage products designed to deliver specific health benefits. Copyright 2010 Elsevier Inc. All rights reserved.

Development and validation of an efficient ultrasound assisted extraction of phenolic compounds from flax (Linum usitatissimum L.) seeds.

PubMed

Corbin, Cyrielle; Fidel, Thibaud; Leclerc, Emilie A; Barakzoy, Esmatullah; Sagot, Nadine; Falguiéres, Annie; Renouard, Sullivan; Blondeau, Jean-Philippe; Ferroud, Clotilde; Doussot, Joël; Lainé, Eric; Hano, Christophe

2015-09-01

Flaxseed accumulates in its seedcoat a macromolecular complex composed of lignan (secoisolariciresinol diglucoside, SDG), flavonol (herbacetin diglucoside, HDG) and hydroxycinnamic acids (p-couramic, caffeic and ferulic acid glucosides). Their antioxidant and/or cancer chemopreventive properties support their interest in human health and therefore, the demand for their extraction. In the present study, ultrasound-assisted extraction (UAE) of flaxseed phenolic compounds was investigated. Scanning Electron Microscopy imaging and histochemical analysis revealed the deep alteration of the seedcoat ultrastructure and the release of the mucilage following ultrasound treatment. Therefore, this method was found to be very efficient for the reduction of mucilage entrapment of flaxseed phenolics. The optimal conditions for UAE phenolic compounds extraction from flaxseeds were found to be: water as solvent supplemented with 0.2N of sodium hydroxide for alkaline hydrolysis of the SDG-HMG complex, an extraction time of 60 min at a temperature of 25°C and an ultrasound frequency of 30 kHz. Under these optimized and validated conditions, highest yields of SDG, HDG and hydroxycinnamic acid glucosides were detected in comparison to other published methods. Therefore, the procedure presented herein is a valuable method for efficient extraction and quantification of the main flaxseed phenolics. Moreover, this UAE is of particular interest within the context of green chemistry in terms of reducing energy consumption and valuation of flaxseed cakes as by-products resulting from the production of flax oil. Copyright © 2015 Elsevier B.V. All rights reserved.

COMPONENT-BASED AND WHOLE-MIXTURE ASSESSMENTS IN ADDRESSING THE UNIDENTIFIED FRACTION OF COMPLEX MIXTURES: DRINKING WATER AS AN EXAMPLE

EPA Science Inventory

Component-Based and Whole-Mixtures Assessments in Addressing the Unidentified Fraction of Complex Mixtures: Drinking Water as an Example

J. E. Simmons; L. K. Teuschler; C. Gennings; T. F. Speth; S. D. Richardson; R. J. Miltner; M. G. Narotsky; K. D. Schenck; G. Rice

Selected phenolic compounds in cultivated plants: ecologic functions, health implications, and modulation by pesticides.

PubMed Central

Daniel, O; Meier, M S; Schlatter, J; Frischknecht, P

1999-01-01

Phenolic compounds are widely distributed in the plant kingdom. Plant tissues may contain up to several grams per kilogram. External stimuli such as microbial infections, ultraviolet radiation, and chemical stressors induce their synthesis. The phenolic compounds resveratrol, flavonoids, and furanocoumarins have many ecologic functions and affect human health. Ecologic functions include defense against microbial pathogens and herbivorous animals. Phenolic compounds may have both beneficial and toxic effects on human health. Effects on low-density lipoproteins and aggregation of platelets are beneficial because they reduce the risk of coronary heart disease. Mutagenic, cancerogenic, and phototoxic effects are risk factors of human health. The synthesis of phenolic compounds in plants can be modulated by the application of herbicides and, to a lesser extent, insecticides and fungicides. The effects on ecosystem functioning and human health are complex and cannot be predicted with great certainty. The consequences of the combined natural and pesticide-induced modulating effects for ecologic functions and human health should be further evaluated. PMID:10229712

14N NQR study of hydrogen bonded complexes of 1,4 diazabicyclo [2,2,2] octane (ted) with phenols and thiourea

NASA Astrophysics Data System (ADS)

Murgich, Juan; Magaly, Santana R.; Diaz, Olga E.

The 14N NQR spectra of H bonded complexes of 1,4 diazabicyclo [2,2,2] octane, also known as triethylenediamine (TED), with phenol (1:2), p-chlorophenol (1:2), p-nitrophenol (1:2), hydroquinone (1:1), resorcinol (1:1) and thiourea (1:2) were observed at 77 K. The 14N frequency shifts produced by the H bonds in the TED complexes were approximately two times larger than those found for similar complexes of Hexamethylenetetramine (HMT). Such change was explained by the effect on the remaining N atoms of the increase in the number of -CH 2- groups and the decrease in N atoms in passing from HMT to TED. From the above results it seems that the inductive effect plays an important role in the formation of H bonds in tertiary amines like HMT and TED.

Phenol oxidation through its adduct formation with chromium complex of 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane: A theoretical study

NASA Astrophysics Data System (ADS)

Narayanan, Jayanthi; Guadalupe, Hernández J.; Thangarasu, Pandiyan

2017-04-01

Structural and electronic properties of [cis-[Cr(tmpcH)X2]n+ (n = 2 or 4; X = OH-, Cl-, Br- and H2O; tmpcH = 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane were analyzed by DFT and TD-DFT methods. The local reactivity active site of the ligand was determined by the condensed-to atom Fukui indexes (CAFI) f(r). In the study, the axial bond distance with metal ion undergoes a considerable change from shorter to longer as OH < Cl- < Br- < H2O, agreeing with the molecular orbital analysis where the dz2 energy is lowered for OH- compared to H2O at the axial position. After analyzing the geometrical data collected from literature for the complexes of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn (II) with tmpcH, it was found that the bond distance decreases with increasing number of d-electrons in the 3d orbital, suggesting that the over-lapping of oribital (π) from Npy with the metal d-orbital is more effective than those from Ncyclam with metal d-orbital. Therefore, the change of different oxidation states for [cis-[Cr(tmpcH)X2]n+ influences significantly the geometrical and electronic parameters. For cis-[Cr(tmpcH)Cl2]2+ the calculated bands are red shifted except for the lower energy band (595 nm) which agrees qualitatively with the experimental one; in addition, the effect of solvent on the electronic transition was analyzed. Furthermore, we collected the electronic data for several chromium complexes from the literature, and compared with our results by plotting the data against number of chromium compounds. Finally, the phenol oxidation properties of the chromium complexes were studied, and phenol forms an adduct with [Cr(tmpcH)Cl]3+ to yield [Cr(tmpcH)Cl-OPh]2+ which could produce the phenol radical, which is enhanced by the presence of -OCH3 group at para- position in the phenolic ring.

Effect of propolis in gastric disorders: inhibition studies on the growth of Helicobacter pylori and production of its urease.

PubMed

Baltas, Nimet; Karaoglu, Sengul Alpay; Tarakci, Cemre; Kolayli, Sevgi

2016-01-01

There is considerable interest in alternative approaches to inhibit Helicobacter pylori (H. pylori) and thus treat many stomach diseases. Propolis is a pharmaceutical mixture containing many natural bioactive substances. The aim of this study was to use propolis samples to treat H. pylori. The anti-H. pylori and anti-urease activities of 15 different ethanolic propolis extracts (EPEs) were tested. The total phenolic contents and total flavonoid contents of the EPE were also measured. The agar-well diffusion assay was carried out on H. pylori strain J99 and the inhibition zones were measured and compared with standards. All propolis extracts showed high inhibition of H. pylori J99, with inhibition diameters ranging from 31.0 to 47.0 mm. Helicobacter pylori urease inhibitory activity was measured using the phenol-hypochlorite assay; all EPEs showed significant inhibition against the enzyme, with inhibition concentrations (IC 50 ; mg/mL) ranging from 0.260 to 1.525 mg/mL. The degree of inhibition was related to the phenolic content of the EPE. In conclusion, propolis extract was found to be a good inhibitor that can be used in H. pylori treatment to improve human health.

Chemical tagging of chlorinated phenols for their facile detection and analysis by NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valdez, Carlos A.; Leif, Roald N.

2015-03-22

A derivatization method that employs diethyl (bromodifluoromethyl) phosphonate (DBDFP) to efficiently tag the endocrine disruptor pentachlorophenol (PCP) and other chlorinated phenols (CPs) along with their reliable detection and analysis by NMR is presented. The method accomplishes the efficient alkylation of the hydroxyl group in CPs with the difluoromethyl (CF 2H) moiety in extremely rapid fashion (5 min), at room temperature and in an environmentally benign manner. The approach proved successful in difluoromethylating a panel of 18 chlorinated phenols, yielding derivatives that displayed unique 1H, 19F NMR spectra allowing for the clear discrimination between isomerically related CPs. Due to its biphasicmore » nature, the derivatization can be applied to both aqueous and organic mixtures where the analysis of CPs is required. Furthermore, the methodology demonstrates that PCP along with other CPs can be selectively derivatized in the presence of other various aliphatic alcohols, underscoring the superiority of the approach over other general derivatization methods that indiscriminately modify all analytes in a given sample. The present work demonstrates the first application of NMR on the qualitative analysis of these highly toxic and environmentally persistent species.« less

Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

NASA Astrophysics Data System (ADS)

Wu, Linkun; Wang, Juanying; Huang, Weimin; Wu, Hongmiao; Chen, Jun; Yang, Yanqiu; Zhang, Zhongyi; Lin, Wenxiong

2015-10-01

Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

Antioxidative properties of defatted dabai pulp and peel prepared by solid phase extraction.

PubMed

Khoo, Hock Eng; Azlan, Azrina; Ismail, Amin; Abas, Faridah

2012-08-14

Solid phase extraction (SPE) using Sep-Pak® cartridges is one of the techniques used for fractionation of antioxidant compounds in waste of dabai oil extraction (defatted dabai parts). The aim of this study was to determine the phenolic compounds and antioxidant capacity in crude extracts and several SPE fractions from methanolic extract of defatted dabai pulp and peel. Based on SPE, Sep-Pak® cyanopropyl and C₁₈ cartridges were used to fractionate the antioxidant-rich crude extracts into water and methanolic fractions. Analyzed using LC-MS, flavonoids, anthocyanins, saponin derivatives and other unknown antioxidative compounds were detected in the defatted dabai crude extracts and their SPE fractions. Anthocyanins were the major phenolic compounds identified in the defatted dabai peel and detected in most of the SPE fractions. Methanolic fractions of defatted dabai parts embraced higher total phenolics and antioxidant capacity than water fractions. This finding also revealed the crude extracts of defatted dabai peel have the most significant antioxidant properties compared to the methanolic and water fractions studied. The crude extract of defatted dabai parts remain as the most potent antioxidant as it contains mixture of flavonoids, anthocyanins and other potential antioxidants.

Liquid class predictor for liquid handling of complex mixtures

DOEpatents

Seglke, Brent W [San Ramon, CA; Lekin, Timothy P [Livermore, CA

2008-12-09

A method of establishing liquid classes of complex mixtures for liquid handling equipment. The mixtures are composed of components and the equipment has equipment parameters. The first step comprises preparing a response curve for the components. The next step comprises using the response curve to prepare a response indicator for the mixtures. The next step comprises deriving a model that relates the components and the mixtures to establish the liquid classes.

Enantioselective Reduction of Ketones Catalyzed by Rare-Earth Metals Complexed with Phenoxy Modified Chiral Prolinols.

PubMed

Song, Peng; Lu, Chengrong; Fei, Zenghui; Zhao, Bei; Yao, Yingming

2018-06-01

Enantioselective reduction of ketones and α,β-unsaturated ketones by pinacolborane (HBpin) has been well-established by using chiral rare-earth metal catalysts with phenoxy modified prolinols. A number of highly optically active alcohols were obtained from reduction of simple ketones catalyzed by ytterbium complex 1 [L 4 Yb(L 4 H)] (H 2 L 4 = ( S)-2- tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol). Moreover, α,β-unsaturated ketones were selectively reduced to a wide range of chiral allylic alcohols with excellent yields, high enantioselectivity, and complete chemoselectivity, catalyzed by a single component chiral ytterbium complex 2 [L 1 Yb(L 1 H)] (H 2 L 1 = ( S)-2,4-di- tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol).

Molecular simulations of palladium catalysed hydrodeoxygenation of 2-hydroxybenzaldehyde using density functional theory.

PubMed

Verma, Anand Mohan; Kishore, Nanda

2017-09-27

The catalytic conversion of 2-hydroxybenzaldehyde (2-HB) is carried out numerically over a Pd(111) surface using density functional theory. The palladium catalyst surface is designed using a 12 atom monolayer and verified with the adsorption of phenol, benzene, anisole, guaiacol, and vanillin; it is found that the adsorption energies along with the adsorption configurations of phenol and benzene are in excellent agreement with the literature. The conversion of 2-HB over the Pd(111) catalyst surface is performed using four reaction schemes: (i) dehydrogenation of the formyl group followed by elimination of CO and association of hydrogen with 2-hydroxyphenyl to produce phenol, (ii) direct elimination of CHO from 2-HB followed by elimination of hydrogen from adsorbed CHO and association of hydrogen with 2-hydroxyphenyl to produce phenol, (iii) direct dehydroxylation of 2-HB followed by association of a hydrogen atom with 2-formylphenyl to produce benzaldehyde, and (iv) dehydrogenation of the hydroxyl group of 2-HB followed by elimination of an oxygen atom and association of a hydrogen atom with 2-formylphenyl to produce benzaldehyde. Along with the reaction mechanisms and their barrier heights, all reaction steps are considered for kinetic modelling in the temperature range 498-698 K with 50 K intervals. The rate constants, pre-exponential factors, and equilibrium constants of all elementary reaction steps are evaluated for each temperature. Kinetic analyses of the catalytic conversion of 2-HB over the Pd(111) surface suggests the production of phenol as an intermediate, instead of benzaldehyde, via dehydrogenation of the formyl group of 2-HB as a first elementary reaction step because of its low activation barrier and the high rate constant of the rate controlling step. Furthermore, the equilibrium constants of the rate controlling step in the production of phenol from 2-HB over the Pd(111) surface report a major fraction of the product in the product mixture even at a low temperature of 498 K.

Characterisation of phenolic compounds by UPLC-QTOF-MS/MS of geopropolis from the stingless bee Melipona subnitida (jandaíra).

PubMed

de Souza, Silvana Alves; da Silva, Telma Maria Guedes; da Silva, Eva Monica Sarmento; Camara, Celso Amorim; Silva, Tania Maria Sarmento

2018-05-17

Melipona subnitida Ducke (jandaíra) is a stingless bee native to north-eastern Brazil, which produces geopropolis, a mixture of beeswax, plant resins, pollens and earth that is used for sealing beehives. To extend the knowledge on phenolic compounds in fractions obtained by C18-solid phase extraction (SPE) of nine geopropolis samples from Melipona subnitida collected at different times. Chromatographic profiles of nine samples of geopropolis from jandaíra were analysed by ultra-performance liquid chromatography coupled with a diode array detector and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF-MS/MS) and combined with the use of data-independent acquisition (MSE) for the profiling and structural characterisation of the phenolic compounds. The isolated compound was identified by nuclear magnetic resonance of hydrogen and carbon ( 1 H- and 13 C-NMR). The present study with geopropolis of jandaíra resulted in the characterisation of 51 phenolics by UPLC-DAD-QTOF-MS/MS: four galloyl glucosides, one ellagic acid, 11 acyl-hexosides, 23 acyl-galloyl-hexosides and 12 flavonoids. The structures of two compounds (1,6-di-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside and 1-O-cinnamoyl-6-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside) were established by 1 H and the attached proton test (APT) experiments as well as high-resolution electrospray ionisation mass spectroscopy (HR-ESI-MS) analysis. The geopropolis of jandaíra showed phenolic compounds galloyl hexosides, ellagic acid, acyl-(cinnamoyl/coumaroyl)-hexosides, acyl-(cinnamoyl/coumaroyl)-galloyl-hexosides and flavonoids (aglycones and acylated-O-glycosides). Copyright © 2018 John Wiley & Sons, Ltd.

Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.

PubMed

Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

2010-12-15

Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts.

Tyrosine-Lipid Peroxide Adducts from Radical Termination: Para-Coupling and Intramolecular Diels-Alder Cyclization

PubMed Central

Shchepin, Roman; Möller, Matias N.; Kim, Hye-young H.; Hatch, Duane M.; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael

2013-01-01

Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogs of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR as well as by mass spectrometry. The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic 13C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl 13C chemical shifts at ~198 ppm. All NMR HMBC and HSQC correlations support the structure assignment of the primary and Diels-Alder adducts, as does MS collision induced dissociation. Kinetic rate constants and activation parameters for the IMDA reaction were determined and the primary adducts were reduced with cuprous ion giving a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found either in the primary or the cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein crosslinks via interprotein Michael adducts. PMID:21090613

Interaction of milk whey protein with common phenolic acids

NASA Astrophysics Data System (ADS)

Zhang, Hao; Yu, Dandan; Sun, Jing; Guo, Huiyuan; Ding, Qingbo; Liu, Ruihai; Ren, Fazheng

2014-01-01

Phenolics-rich foods such as fruit juices and coffee are often consumed with milk. In this study, the interactions of α-lactalbumin and β-lactoglobulin with the phenolic acids (chlorogenic acid, caffeic acid, ferulic acid, and coumalic acid) were examined. Fluorescence, CD, and FTIR spectroscopies were used to analyze the binding modes, binding constants, and the effects of complexation on the conformation of whey protein. The results showed that binding constants of each whey protein-phenolic acid interaction ranged from 4 × 105 to 7 × 106 M-n and the number of binding sites n ranged from 1.28 ± 0.13 to 1.54 ± 0.34. Because of these interactions, the conformation of whey protein was altered, with a significant reduction in the amount of α-helix and an increase in the amounts of β-sheet and turn structures.

The probability of growth of Listeria monocytogenes in cooked salmon and tryptic soy broth as affected by salt, smoke compound, and storage temperature.

PubMed

Hwang, Cheng-An

2009-05-01

The objectives of this study were to examine and model the probability of growth of Listeria monocytogenes in cooked salmon containing salt and smoke (phenol) compound and stored at various temperatures. A growth probability model was developed, and the model was compared to a model developed from tryptic soy broth (TSB) to assess the possibility of using TSB as a substitute for salmon. A 6-strain mixture of L. monocytogenes was inoculated into minced cooked salmon and TSB containing 0-10% NaCl and 0-34 ppm phenol to levels of 10(2-3) cfu/g, and the samples were vacuum-packed and stored at 0--25 degrees C for up to 42 days. A total 32 treatments, each with 16 samples, selected by central composite designs were tested. A logistic regression was used to model the probability of growth of L. monocytogenes as a function of concentrations of salt and phenol, and storage temperature. Resulted models showed that the probabilities of growth of L. monocytogenes in both salmon and TSB decreased when the salt and/or phenol concentrations increased, and at lower storage temperatures. In general, the growth probabilities of L. monocytogenes were affected more profoundly by salt and storage temperature than by phenol. The growth probabilities of L. monocytogenes estimated by the TSB model were higher than those by the salmon model at the same salt/phenol concentrations and storage temperatures. The growth probabilities predicted by the salmon and TSB models were comparable at higher storage temperatures, indicating the potential use of TSB as a model system to substitute salmon in studying the growth behavior of L. monocytogenes may only be suitable when the temperatures of interest are in higher storage temperatures (e.g., >12 degrees C). The model for salmon demonstrated the effects of salt, phenol, and storage temperature and their interactions on the growth probabilities of L. monocytogenes, and may be used to determine the growth probability of L. monocytogenes in smoked seafood.

Thermal transformation of bioactive caffeic acid on fumed silica seen by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry and quantum chemical methods.

PubMed

Kulik, Tetiana V; Lipkovska, Natalia O; Barvinchenko, Valentyna M; Palyanytsya, Borys B; Kazakova, Olga A; Dudik, Olesia O; Menyhárd, Alfréd; László, Krisztina

2016-05-15

Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability. Copyright © 2016 Elsevier Inc. All rights reserved.

COMPLEX MIXTURES OF CHEMICAL CARCINOGENS: PRINCIPLES OF ACTION AND HUMAN CANCER

EPA Science Inventory

There is strong epidemiological evidence supported by experimental animal data that complex environmental mixtures pose a risk to human health producing increases in cancer incidence. Understanding the chemical and biological properties of these mixtures leads to a clearer unde...

Impact of environmental pollutants on the male: effects on germ cell differentiation

PubMed Central

Rao Veeramachaneni, D. N.

2008-01-01

A variety of so-called innocuous chemicals can have insidious and long lasting effects on the developing male reproductive system. Developmental exposures of male rabbits to common industrial contaminants in drinking water (a mixture of arsenic, chromium, lead, benzene, chloroform, phenol, and trichloroethylene); alkyl phenols (e.g. octylphenol); water disinfection by-products (e.g. dibromoacetic acid); anti-androgenic pesticides (e.g. p,p’-DDT and vinclozolin); and plasticizers (e.g. dibutyl phthalate) produce testicular dysgenesis. The lesions include testicular carcinoma in situ, also called intratubular germ cell neoplasia—the precursor lesion of germ cell tumors in men, and acrosomal dysgenesis—characterized by sharing of a dysplastic acrosome by two or more spermatids resulting in characteristic sperm acrosomal-nuclear malformations. Certain manifestations of testicular dysgenesis arch across environmental agents, and sequelae of intentional developmental exposures of rabbits duplicate what has been encountered in deer, horses, and humans for which the etiology is uncertain. PMID:18155861

Structural wood panels with improved fire resistance

NASA Technical Reports Server (NTRS)

Sawko, P. M. (Inventor)

1980-01-01

Structural wood paneling or other molded wood compositions consisting of finely divided wood chips, flour, or strands are bound together and hot pressed with a modified novolac resin which is the cured product of a prepolymer made from an aralkyl ether or halide with a phenol and a hardening agent such as hexamethylene tetramine. The fire resistance of these articles is further improved by incorporating in the binder certain inorganic fillers, especially a mixture of ammonium oxalate and ammonium phosphate.

Direct measurement of total antioxidant capacity of cereals: QUENCHER-CUPRAC method.

PubMed

Tufan, Ayşe Nur; Celik, S Esin; Ozyürek, Mustafa; Güçlü, Kubilay; Apak, Reşat

2013-04-15

Polyphenols in cereal samples are distributed as free, soluble-esterified, and insoluble-bound forms either esterified or etherified to cell wall constituents. In the evaluation of total antioxidant capacity (TAC) of cereals, rather difficult and time-consuming acid, alkaline and enzymatic treatments of residue have been applied to complete the extraction of bound phenolic compounds. Thus, this work is aimed to measure the TAC of cereals (i.e. barley, wheat, rye, oat) by the 'QUENCHER procedure' (involving forced solubilization of bound phenolics by oxidizing TAC reagents) with the direct use of copper(II)-neocuproine (Cu(II)-Nc) reagent of the CUPric Reducing Antioxidant Capacity (CUPRAC) assay. In this novel 'QUENCHER-CUPRAC' method, reaction time and solvent composition parameters were optimized, and the method was applied to cereal samples with CUPRAC reagent dissolved in 1:1 (v/v) ethanol-water mixture. The antioxidant capacities of soluble and insoluble fractions were simultaneously measured to give a hierarchic TAC order of cereals as: barley>rye>oat>wheat. The TAC values of cereals measured by QUENCHER-CUPRAC were higher than those of original QUENCHER method using ABTS(•+) and DPPH reagents. Polyphenolic mixtures in a cellulose matrix gave additive TAC values with QUENCHER-CUPRAC. The proposed method correlated linearly with QUENCHER-ABTS(•+) (r=0.956) and QUENCHER-DPPH (r=0.976). Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of plant diversity on the diversity of soil organic compounds.

PubMed

El Moujahid, Lamiae; Le Roux, Xavier; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

2017-01-01

The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms.

Effect of plant diversity on the diversity of soil organic compounds

PubMed Central

El Moujahid, Lamiae; Michalet, Serge; Bellvert, Florian; Weigelt, Alexandra; Poly, Franck

2017-01-01

The effect of plant diversity on aboveground organisms and processes was largely studied but there is still a lack of knowledge regarding the link between plant diversity and soil characteristics. Here, we analyzed the effect of plant identity and diversity on the diversity of extractible soil organic compounds (ESOC) using 87 experimental grassland plots with different levels of plant diversity and based on a pool of over 50 plant species. Two pools of low molecular weight organic compounds, LMW1 and LMW2, were characterized by GC-MS and HPLC-DAD, respectively. These pools include specific organic acids, fatty acids and phenolics, with more organic acids in LMW1 and more phenolics in LMW2. Plant effect on the diversity of LMW1 and LMW2 compounds was strong and weak, respectively. LMW1 richness observed for bare soil was lower than that observed for all planted soils; and the richness of these soil compounds increased twofold when dominant plant species richness increased from 1 to 6. Comparing the richness of LMW1 compounds observed for a range of plant mixtures and for plant monocultures of species present in these mixtures, we showed that plant species richness increases the richness of these ESOC mainly through complementarity effects among plant species associated with contrasted spectra of soil compounds. This could explain previously reported effects of plant diversity on the diversity of soil heterotrophic microorganisms. PMID:28166250

Selective extraction of high-value phenolic compounds from distillation wastewater of basil (Ocimum basilicum L.) by pressurized liquid extraction.

PubMed

Pagano, Imma; Sánchez-Camargo, Andrea Del Pilar; Mendiola, Jose Antonio; Campone, Luca; Cifuentes, Alejandro; Rastrelli, Luca; Ibañez, Elena

2018-01-31

During the essential oil steam distillation from aromatic herbs, huge amounts of distillation wastewaters (DWWs) are generated. These by-products represent an exceptionally rich source of phenolic compounds such as rosmarinic acid (RA) and caffeic acid (CA). Herein, the alternative use of dried basil DWWs (dDWWs) to perform a selective extraction of RA and CA by pressurized liquid extraction (PLE) employing bio-based solvent was studied. To select the most suitable solvent for PLE, the theoretical modelling of Hansen solubility parameters (HSP) was carried out. This approach allows reducing the list of candidate to two solvents: ethanol and ethyl lactate. Due to the composition of the sample, mixtures of water with those solvents were also tested. An enriched PLE extract in RA (23.90 ± 2.06 mg/g extract) with an extraction efficiency of 75.89 ± 16.03% employing a water-ethanol mixture 25:75 (% v/v) at 50°C was obtained. In the case of CA, a PLE extract with 2.42 ± 0.04 mg/g extract, having an extraction efficiency of 13.86 ± 4.96% using ethanol absolute at 50°C was achieved. DWWs are proposed as new promising sources of natural additives and/or functional ingredients for cosmetic, nutraceutical, and food applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biomorphous SiC ceramics prepared from cork oak as precursor

NASA Astrophysics Data System (ADS)

Yukhymchuk, V. O.; Kiselov, V. S.; Valakh, M. Ya.; Tryus, M. P.; Skoryk, M. A.; Rozhin, A. G.; Kulinich, S. A.; Belyaev, A. E.

2016-04-01

Porous ceramic materials of SiC were synthesized from carbon matrices obtained via pyrolysis of natural cork as precursor. We propose a method for the fabrication of complex-shaped porous ceramic hardware consisting of separate parts prepared from natural cork. It is demonstrated that the thickness of the carbon-matrix walls can be increased through their impregnation with Bakelite phenolic glue solution followed by pyrolysis. This decreases the material's porosity and can be used as a way to modify its mechanical and thermal characteristics. Both the carbon matrices (resulted from the pyrolysis step) and the resultant SiC ceramics are shown to be pseudomorphous to the structure of initial cork. Depending on the synthesis temperature, 3C-SiC, 6H-SiC, or a mixture of these polytypes, could be obtained. By varying the mass ratio of initial carbon and silicon components, stoichiometric SiC or SiC:C:Si, SiC:C, and SiC:Si ceramics could be produced. The structure, as well as chemical and phase composition of the prepared materials were studied by means of Raman spectroscopy and scanning electron microscopy.

Hydroxytyrosol and its complex forms (secoiridoids) modulate aorta and heart proteome in healthy rats: Potential cardio-protective effects.

PubMed

Catalán, Úrsula; Rubió, Laura; López de Las Hazas, Maria-Carmen; Herrero, Pol; Nadal, Pedro; Canela, Núria; Pedret, Anna; Motilva, Maria-José; Solà, Rosa

2016-10-01

Hydroxytyrosol (HT) is the major phenolic compound in virgin olive oil (VOO) in both free and complex forms (secoiridoids; SEC). Proteomics of cardiovascular tissues such as aorta or heart represents a promising tool to uncover the mechanisms of action of phenolic compounds in healthy animals. Twelve female Wistar rats were separated into three groups: a standard diet and two diets supplemented in phenolic compounds (HT and SEC) adjusted to 5 mg/kg/day during 21 days. Proteomic analyses of aorta and heart tissues were performed by nano-LC and MS. Ingenuity Pathway Analysis was used to generate interaction networks. HT or SEC modulated aorta and heart proteome compared to the standard diet. The top-scored networks were related to Cardiovascular System. HT and SEC downregulated proteins related to proliferation and migration of endothelial cells and occlusion of blood vessels in aorta and proteins related to heart failure in heart tissue. SEC showed higher fold change values compared to HT, attributed to higher concentration of HT detected in heart tissue. Changes at proteomic level in cardiovascular tissues may partially account for the underlying mechanisms of VOO phenols cardiovascular protection being the SEC effects higher than free HT. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of two bacterial strains for wastewater bioremediation and assessment of phenolics biodegradation.

PubMed

Paisio, Cintia E; Quevedo, María R; Talano, Melina A; González, Paola S; Agostini, Elizabeth

2014-08-01

The use of native bacteria is a useful strategy to decontaminate industrial effluents. In this work, two bacterial strains isolated from polluted environments constitutes a promising alternative since they were able to remove several phenolic compounds not only from synthetic solutions but also from effluents derived from a chemical industry and a tannery which are complex matrices. Acinetobacter sp. RTE 1.4 showed ability to completely remove 2-methoxyphenol (1000 mg/L) while Rhodococcus sp. CS 1 not only degrade the same concentration of this compound but also removed 4- chlorophenol, 2,4-dichlorophenol and pentachlorophenol with high efficiency. Moreover, both bacteria degraded phenols naturally present or even exogenously added at high concentrations in effluents from the chemical industry and a tannery in short time (up to 5 d). In addition, a significant reduction of biological oxygen demand and chemical oxygen demand values was achieved after 7 d of treatment for both effluents using Acinetobacter sp. RTE 1.4 and Rhodococcus sp. CS1, respectively. These results showed that Acinetobacter sp. RTE1.4 and Rhodococcus sp. CS 1 might be considered as useful biotechnological tools for an efficient treatment of different effluents, since they showed wide versatility to detoxify these complex matrices, even supplemented with high phenol concentrations.

Saturation kinetics in phenolic O-H bond oxidation by a mononuclear Mn(III)-OH complex derived from dioxygen.

PubMed

Wijeratne, Gayan B; Corzine, Briana; Day, Victor W; Jackson, Timothy A

2014-07-21

The mononuclear hydroxomanganese(III) complex, [Mn(III)(OH)(dpaq)](+), which is supported by the amide-containing N5 ligand dpaq (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate) was generated by treatment of the manganese(II) species, [Mn(II)(dpaq)](OTf), with dioxygen in acetonitrile solution at 25 °C. This oxygenation reaction proceeds with essentially quantitative yield (greater than 98% isolated yield) and represents a rare example of an O2-mediated oxidation of a manganese(II) complex to generate a single product. The X-ray diffraction structure of [Mn(III)(OH)(dpaq)](+) reveals a short Mn-OH distance of 1.806(13) Å, with the hydroxo moiety trans to the amide function of the dpaq ligand. No shielding of the hydroxo group is observed in the solid-state structure. Nonetheless, [Mn(III)(OH)(dpaq)](+) is remarkably stable, decreasing in concentration by only 10% when stored in MeCN at 25 °C for 1 week. The [Mn(III)(OH)(dpaq)](+) complex participates in proton-coupled electron transfer reactions with substrates with relatively weak O-H and C-H bonds. For example, [Mn(III)(OH)(dpaq)](+) oxidizes TEMPOH (TEMPOH = 2,2'-6,6'-tetramethylpiperidine-1-ol), which has a bond dissociation free energy (BDFE) of 66.5 kcal/mol, in MeCN at 25 °C. The hydrogen/deuterium kinetic isotope effect of 1.8 observed for this reaction implies a concerted proton-electron transfer pathway. The [Mn(III)(OH)(dpaq)](+) complex also oxidizes xanthene (C-H BDFE of 73.3 kcal/mol in dimethylsulfoxide) and phenols, such as 2,4,6-tri-t-butylphenol, with BDFEs of less than 79 kcal/mol. Saturation kinetics were observed for phenol oxidation, implying an initial equilibrium prior to the rate-determining step. On the basis of a collective body of evidence, the equilibrium step is attributed to the formation of a hydrogen-bonding complex between [Mn(III)(OH)(dpaq)](+) and the phenol substrates.

Relationship between red wine grades and phenolics. 1. Tannin and total phenolics concentrations.

PubMed

Mercurio, Meagan D; Dambergs, Robert G; Cozzolino, Daniel; Herderich, Markus J; Smith, Paul A

2010-12-08

Measuring chemical composition is a common approach to support decisions about allocating foods and beverages to grades related to market value. Red wine is a particularly complex beverage, and multiple compositional attributes are needed to account for its sensory properties, including measurement of key phenolic components such as anthocyanins, total phenolics, and tannin, which are related to color and astringency. Color has been shown to relate positively to red wine grade; however, little research has been presented that explores the relationship between astringency-related components such as total phenolic or tannin concentration and wine grade. The aim of this research has been to investigate the relationship between the wine grade allocations of commercial wineries and total phenolic and tannin concentrations, respectively, in Australian Shiraz and Cabernet Sauvignon wines. Total phenolic and tannin concentrations were determined using the methyl cellulose precipitable (MCP) tannin assay and then compared to wine grade allocations made by winemaker panels during the companies' postvintage allocation process. Data were collected from wines produced by one Australian wine company over the 2005, 2006, and 2007 vintages and by a further two companies in 2007 (total wines = 1643). Statistical analysis revealed a positive trend toward higher wine grade allocation and wines that had higher concentrations of both total phenolics and tannin, respectively. This research demonstrates that for these companies, in general, Cabernet Sauvignon and Shiraz wines allocated to higher market value grades have higher total phenolics and higher tannin concentrations and suggests that these compositional parameters should be considered in the development of future multiparameter decision support systems for relevant commercial red wine grading processes. In addition, both tannin and total phenolics would ideally be included because although, in general, a positive relationship exists between the two parameters, this relationship does not hold for all wine styles.

Diagenesis of conifer needles in a coastal marine environment

NASA Astrophysics Data System (ADS)

Hedges, John I.; Weliky, K.

1989-10-01

Physically intact fir, hemlock and cedar needles were isolated from different horizons of a sediment core from a coastal marine bay (Dabob Bay, Washington State, U.S.A.) and from nearby trees and forest litter. Green fir, hemlock and cedar needles were all characterized by glucose-rich aldose mixtures (~30% of tissue carbon), the production of vanillyl and cinnamyl CuO-derived phenols (~8% of tissue carbon) and the presence of both pinitol and myo-inositol (1-2% of tissue carbon). Needles from forest litter were enriched in lignin phenols and non-glucose aldoses and depleted in glucose and cyclitols. The sediment core contained an average of 10 mg/1 of physically intact fir, hemlock and cedar needles, which occurred in similar relative abundances and accounted for less than 1% of the total nonwoody gymnosperm tissue. Compared to the green and litter counterparts, all sedimentary needles were greatly depleted in cyclitols, glucose and p-coumaric acid and enriched in vanillyl phenol precursors. The degree of elevation of vanillyl phenol yield from the degraded needles was used to estimate minimal carbon losses from the samples, which ranged from near 40% for needle litter to almost 70% for the deepest (~100 years old) sedimentary fir/hemlock samples. Although downcore increases in carbon loss and refractory organic components indicated in situ diagenesis, the bulk of overall degradation occurred either on land or during the first 10-20 years after deposition. Atomic C/N ratios of degraded needles were lower than for green counterparts, but nitrogen was lost overall. These relative changes indicate the following stability series: vanillyl phenols > N > ferulic acid, p-hydroxy phenols, most aldoses and bulk tissue > glucose and p-coumaric acid > cyclitols (near 100% loss). Vanillic acid to vanillin ratios, (Ad/Al)v, of the green fir and hemlock needles were unusually high (0.36-0.38) and decreased downcore. Diagenesis also decreased the cinnamyl/vanillyl phenol ratio (C/V) of the deepest sedimentary fir/hemlock needles to 20% of the original value and almost tripled the carbon-normalized yield of total vanillyl plus cinnamyl phenols (Λ). The net result of these compositional variations was to make the lignin component of the buried conifer needles resemble lignin in gymnosperm wood, thereby leading to underestimates of needle input and mass.

The interplay of hydrogen bonding and dispersion in phenol dimer and trimer: structures from broadband rotational spectroscopy.

PubMed

Seifert, Nathan A; Steber, Amanda L; Neill, Justin L; Pérez, Cristóbal; Zaleski, Daniel P; Pate, Brooks H; Lesarri, Alberto

2013-07-21

The structures of the phenol dimer and phenol trimer complexes in the gas phase have been determined using chirped-pulse Fourier transform microwave spectroscopy in the 2-8 GHz band. All fourteen (13)C and (18)O phenol dimer isotopologues were assigned in natural abundance. A full heavy atom experimental substitution structure was determined, and a least-squares fit ground state r0 structure was determined by proper constraint of the M06-2X/6-311++g(d,p) ab initio structure. The structure of phenol dimer features a water dimer-like hydrogen bond, as well as a cooperative contribution from inter-ring dispersion. Comparisons between the experimental structure and previously determined experimental structures, as well as ab initio structures from various levels of theory, are discussed. For phenol trimer, a C3 symmetric barrel-like structure is found, and an experimental substitution structure was determined via measurement of the six unique (13)C isotopologues. The least-squares fit rm((1)) structure reveals a similar interplay between hydrogen bonding and dispersion in the trimer, with water trimer-like hydrogen bonding and C-H···π interactions.

Origins of Protons in C-H Bond Insertion Products of Phenols: Proton-Self-Sufficient Function via Water Molecules.

PubMed

Luo, Zhoujie; Gao, Ya; Zhu, Tong; Zhang, John Zenghui; Xia, Fei

2017-08-31

Water molecules can serve as proton shuttles for proton transfer in the C-H bond insertion reactions catalyzed by transition metal complexes. Recently, the control experiments performed for C-H bond insertion of phenol and anisol by gold carbenes show that large discrepancy exists in the yields of hydrogenated and deuterated products. Thus, we conducted a detailed theoretical analysis on the function of water molecules in the C-H bond insertion reactions. The comparison of calculated results and control experiments indicates that the solution water molecules play a crucial role of proton shuttle in C-H bond insertion. In particular, it was found that the hydroxyl groups in phenols were capable of donating protons via water shuttles for the production of C-H products, which had a substantial influence on the yields of inserted products. The hydroxyl groups instead of C-H bonds in phenols function like "proton reservoirs" in the C-H bond insertion, which we call the "proton self-sufficient" (PSS) function of phenol. The PSS function of phenol indicates that the substrates with and without proton reservoirs will lead to different C-H bond insertion products.

Antimicrobial and Antiradical Activity of Extracts Obtained from Leaves of Five Species of the Genus Bergenia: Identification of Antimicrobial Compounds.

PubMed

Żbikowska, Beata; Franiczek, Roman; Sowa, Alina; Połukord, Grażyna; Krzyżanowska, Barbara; Sroka, Zbigniew

2017-09-01

An important focus of modern medicine is the search for new substances and strategies to combat infectious diseases, which present an increasing threat due to the growth of bacterial resistance to antibiotics. Another problem concerns free radicals, which in excess can cause several serious diseases. An alternative to chemical synthesis of antimicrobial and antiradical compounds is to find active substances in plant raw materials. We prepared extracts from leaves of five species of the genus Bergenia: B. purpurascens, B. cordifolia, B. ligulata, B. crassifolia, and B. ciliata. Antimicrobial and antiradical features of extracts and raw materials were assessed, and the quantities of phenolic compounds were determined. We also evaluated, using high-performance liquid chromatography, the amounts of arbutin and hydroquinone, compounds related to antimicrobial activity of these raw materials. The strongest antiradical properties were shown by leaves of B. crassifolia and B. cordifolia, the lowest by leaves of B. ciliata. The antiradical activity of extracts showed a strong positive correlation with the amount of phenols. All raw materials have significant antimicrobial properties. Among them, the ethyl acetate extracts were the most active. Antimicrobial activity very weakly correlated with the amount of arbutin, but correlated very strongly with the contents of both hydroquinone and phenolic compounds. Additional experiments using artificially prepared mixtures of phenolic compounds and hydroquinone allowed us to conclude that the most active antimicrobial substance is hydroquinone.

Analytic Complexity and Challenges in Identifying Mixtures of Exposures Associated with Phenotypes in the Exposome Era.

PubMed

Patel, Chirag J

2017-01-01

Mixtures, or combinations and interactions between multiple environmental exposures, are hypothesized to be causally linked with disease and health-related phenotypes. Established and emerging molecular measurement technologies to assay the exposome , the comprehensive battery of exposures encountered from birth to death, promise a new way of identifying mixtures in disease in the epidemiological setting. In this opinion, we describe the analytic complexity and challenges in identifying mixtures associated with phenotype and disease. Existing and emerging machine-learning methods and data analytic approaches (e.g., "environment-wide association studies" [EWASs]), as well as large cohorts may enhance possibilities to identify mixtures of correlated exposures associated with phenotypes; however, the analytic complexity of identifying mixtures is immense. If the exposome concept is realized, new analytical methods and large sample sizes will be required to ascertain how mixtures are associated with disease. The author recommends documenting prevalent correlated exposures and replicated main effects prior to identifying mixtures.

Plant secondary metabolites and gut health: the case for phenolic acids.

PubMed

Russell, Wendy; Duthie, Garry

2011-08-01

Plant-based diets contain a plethora of secondary metabolites that may impact on health and disease prevention. Much attention has been focused on the potential bioactivity and nutritional relevance of several classes of phytochemicals such as flavonoids, carotenoids, phyto-oestrogens and glucosinolates. Less attention has been paid to simple phenolic acids that are widely found in fruit, vegetables, herbs, spices and beverages. Daily intakes may exceed 100 mg. In addition, bacteria in the gut can perform reactions that transform more complex plant phenolics such as anthocyanins, procyanidins, flavanones, flavonols, tannins and isoflavones into simple phenolic metabolites. The colon is thus a rich source of potentially active phenolic acids that may impact both locally and systemically on gut health. Both the small and large intestine (colon) contain absorption sites for phenolic acids but low post-prandial concentrations in plasma indicate minimal absorption early in the gastrointestinal tract and/or rapid hepatic metabolism and excretion. Therefore, any bioactivity that contributes to gut health may predominantly occur in the colon. Several phenolic acids affect the expression and activity of enzymes involved in the production of inflammatory mediators of pathways thought to be important in the development of gut disorders including colon cancer. However, at present, we remain largely ignorant as to which of these compounds are beneficial to gut health. Until we can elucidate which pro-inflammatory and potentially carcinogenetic changes in gene expression can be moderated by simple phenolic acids, it is not possible to recommend specific plant-based foods rich in particular phenolics to optimise gut health.

Structure Properties and Mechanisms of Action of Naturally Originated Phenolic Acids and Their Derivatives against Human Viral Infections.

PubMed

Wu, Yi-Hang; Zhang, Bing-Yi; Qiu, Li-Peng; Guan, Rong-Fa; Ye, Zi-Hong; Yu, Xiao-Ping

2017-01-01

A great effort has been made to develop efficacious antiviral drugs, but many viral infections are still lack of efficient antiviral therapies so far. The related exploration of natural products to fight viruses has been raised in recent years. Natural compounds with structural diversity and complexity offer a great chance to find new antiviral agents. Particularly, phenolic acids have attracted considerable attention owing to their potent antiviral abilities and unique mechanisms. The aim of this review is to report new discoveries and updates pertaining to antiviral phenolic acids. The relevant references on natural phenolic acids were searched. The antiviral phenolic acids were classified according to their structural properties and antiviral types. Meanwhile, the antiviral characteristics and structure-activity relationships of phenolic acids and their derivatives were summarized. The review finds that natural phenolic acids and their derivatives possessed potent inhibitory effects on multiple virus in humans such as human immunodeficiency virus, hepatitis C virus, hepatitis B virus, herpes simplex virus, influenza virus and respiratory syncytial virus. In particular, caffeic acid/gallic acid and their derivatives exhibited outstanding antiviral properties by a variety of modes of action. Naturally derived phenolic acids especially caffeic acid/gallic acid and their derivatives may be regarded as novel promising antiviral leads or candidates. Additionally, scarcely any of these compounds has been used as antiviral treatment in clinical practice. Therefore, these phenolic acids with diverse skeletons and mechanisms provide us an excellent resource for finding novel antiviral drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Radionuclide-binding compound, a radionuclide delivery system, a method of making a radium complexing compound, a method of extracting a radionuclide, and a method of delivering a radionuclide

DOEpatents

Fisher, Darrell R.; Wai, Chien M.; Chen, Xiaoyuan

2000-01-01

The invention pertains to compounds which specifically bind radionuclides, and to methods of making radionuclide complexing compounds. In one aspect, the invention includes a radionuclide delivery system comprising: a) a calix[n]arene-crown-[m]-ether compound, wherein n is an integer greater than 3, and wherein m is an integer greater than 3, the calix[n]arene-crown-[m]-ether compound comprising at least two ionizable groups; and b) an antibody attached to the calix[n]arene-crown-[m]-ether compound. In another aspect, the invention includes a method of making a radium complexing compound, comprising: a) providing a calix[n]arene compound, wherein n is an integer greater than 3, the calix[n]arene compound comprising n phenolic hydroxyl groups; b) providing a crown ether precursor, the crown ether precursor comprising a pair of tosylated ends; c) reacting the pair of tosylated ends with a pair of the phenolic hydroxyl groups to convert said pair of phenolic hydroxyl groups to ether linkages, the ether linkages connecting the crown ether precursor to the calix[n]arene to form a calix[n]arene-crown-[m]-ether compound, wherein m is an integer greater than 3; d) converting remaining phenolic hydroxyl groups to esters; e) converting the esters to acids, the acids being proximate a crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound; and f) providing a Ra.sup.2+ ion within the crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound.

Capillary electrophoresis-electrospray ionization-mass spectrometry method to determine the phenolic fraction of extra-virgin olive oil.

PubMed

Carrasco-Pancorbo, Alegría; Arráez-Román, David; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2006-06-01

We describe the first analytical method involving SPE and CZE coupled to ESI-IT MS (CZE-ESI-MS) used to identify and characterize phenolic compounds in olive oil samples. The SPE, CZE and ESI-MS parameters were optimized in order to maximize the number of phenolic compounds detected and the sensitivity of their determination. To this end we have devised a detailed method to find the best conditions for CE separation and the detection by MS of the phenolic compounds present in olive oil using a methanol-water extract of Picual extra-virgin olive oil (VOO). Electrophoretic separation was carried out using an aqueous CE buffer system consisting of 60 mM NH(4)OAc at pH 9.5 with 5% of 2-propanol, a sheath liquid containing 2-propanol/water 60:40 v/v and 0.1% v/v triethylamine. This method offers to the analyst the chance to study important phenolic compounds such as phenolic alcohols (tyrosol (TY), hydroxytyrosol (HYTY) and 2-(4-hydroxyphenyl)ethyl acetate), lignans ((+)-pinoresinol and (+)-1-acetoxypinoresinol), complex phenols (ligstroside aglycon (Lig Agl), oleuropein aglycon, their respective decarboxylated derivatives and several isomeric forms of these (dialdehydic form of oleuropein aglycon, dialdehydic form of ligstroside aglycon, dialdehydic form of decarboxymethyl elenolic acid linked to HYTY, dialdehydic form of decarboxymethyl elenolic acid linked to TY) and 10-hydroxy-oleuropein aglycon) and one other phenolic compound (elenolic acid) in extra-VOO by using a simple SPE before CE-ESI-MS analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Xin; Zhou, Pei; Zheng, Chunying

A copper complex ([Cu(py){sub 2}(L){sub 2}]·2CH{sub 3}OH){sub n} (HL=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) (1) with acrylic acid ligand was synthesized and structurally analyzed by IR, elemental analysis, TGA and the single-crystal X-ray diffraction methods. It is the first time to find that phenolic hydroxyl of L coordinates to Cu(II). Complex 1 exhibits 1D chain by a double-bridge of ligands, and the 3D supramolecular framework in complex 1 is constructed by π–π stacking interactions and van der Waals Contacts among the 1D chains. The magnetic properties of complex 1 have been studied. - Graphical abstract: A copper complex based on (E)-3-(3-hydroxyl-phenyl)-acrylic acid in amore » novel coordinated way was synthesized and a ferromagnetic exchange interactions between neighboring Cu(II) ions has be achieved. - Highlights: • A new copper complex with acrylic acid ligand was synthesized and analyzed. • We find the phenolic hydroxyl of MCA ligand coordinates to metal ion firstly. • A ferromagnetic exchange interactions between Cu(II) ions has been achieved.« less

Synthesis and spectral characterization of Schiff base complexes of Cu(II), Co(II), Zn(II) and VO(IV) containing 4-(4-aminophenyl)morpholine derivatives: Antimicrobial evaluation and anticancer studies

NASA Astrophysics Data System (ADS)

Dhahagani, K.; Mathan Kumar, S.; Chakkaravarthi, G.; Anitha, K.; Rajesh, J.; Ramu, A.; Rajagopal, G.

2014-01-01

Metal(II) chelates of Schiff bases derived from the condensation of 4-morpholinoaniline with substituted salicylaldehyde have been prepared and characterized by 1H NMR, IR, electronic, EPR, and magnetic measurement studies. The complexes are of the type M(X-MPMP)2 [where M = Cu(II), Co(II)), Zn(II), or VO(IV); MPMP = 2-[(4 morpholinophenyl imino) methyl] 4-X-phenol, X = Cl, (L1H), X = Br (L2H)]. Single crystal X-ray crystallography studies confirm the structure of newly synthesized Schiff bases. The Schiff bases act as bidentate monobasic ligands, coordinating through deprotonated phenolic oxygen and azomethine nitrogen atoms. The free ligands and metal complexes are screened for their biopotency. Metal complexes exhibit better activity than ligands. Anticancer activity of ligands and their metal complexes are evaluated in human heptocarcinoma(HepG2) cells. The preliminary bioassay indicates that the Schiff base and its zinc complex exhibit inhibitory activity against the human gastric cancer cell lines.

Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarvis, Ian W.H., E-mail: Ian.Jarvis@ki.se; Bergvall, Christoffer, E-mail: Christoffer.Bergvall@anchem.su.se; Bottai, Matteo, E-mail: Matteo.Bottai@ki.se

2013-02-01

Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNAmore » damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs. -- Highlights: ► Benzo[a]pyrene (BP), dibenzo[a,l]pyrene (DBP) and air PM PAH extracts were compared. ► Binary mixture of BP and DBP induced a more than additive DNA damage response. ► Air PM PAH extracts were more potent than toxicity equivalency factor estimates. ► Larger PAHs (> 4 rings) contribute more to the genotoxicity of PAHs in air PM. ► Chk1 is a sensitive marker for persistent activation of DNA damage signaling from PAH mixtures.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H 2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H 2 production, as well as the anode microbial community structure were investigated. The five compoundsmore » were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H 2 yield varied from 0.26 to 0.42 g H 2-COD/g COD removed in the anode, and the bioanode volume-normalized H 2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H 2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H 2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H 2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

Iron and its complexation by phenolic cellular metabolites

PubMed Central

Chobot, Vladimir

2010-01-01

Iron is a transition metal that forms chelates and complexes with various organic compounds, also with phenolic plant secondary metabolites. The ligands of iron affect the redox potential of iron. Electrons may be transferred either to hydroxyl radicals, hydrogen peroxide or molecular oxygen. In the first case, oxidative stress is decreased, in the latter two cases, oxidative stress is increased. This milieu-dependent mode of action may explain the non-linear mode of action of juglone and other secondary metabolites. Attention to this phenomenon may help to explain idiosyncratic and often nonlinear effects that result in biological assays. Current chemical assays are discussed that help to explore these aspects of redox chemistry. PMID:20592800

Enhanced photoluminescence from single nitrogen-vacancy defects in nanodiamonds coated with phenol-ionic complexes.

PubMed

Bray, Kerem; Previdi, Rodolfo; Gibson, Brant C; Shimoni, Olga; Aharonovich, Igor

2015-03-21

Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications.

Evaluating the similarity of complex drinking-water disinfection by-product mixtures: overview of the issues.

PubMed

Rice, Glenn E; Teuschler, Linda K; Bull, Richard J; Simmons, Jane E; Feder, Paul I

2009-01-01

Humans are exposed daily to complex mixtures of environmental chemical contaminants, which arise as releases from sources such as engineering procedures, degradation processes, and emissions from mobile or stationary sources. When dose-response data are available for the actual environmental mixture to which individuals are exposed (i.e., the mixture of concern), these data provide the best information for dose-response assessment of the mixture. When suitable data on the mixture itself are not available, surrogate data might be used from a sufficiently similar mixture or a group of similar mixtures. Consequently, the determination of whether the mixture of concern is "sufficiently similar" to a tested mixture or a group of tested mixtures is central to the use of whole mixture methods. This article provides an overview for a series of companion articles whose purpose is to develop a set of biostatistical, chemical, and toxicological criteria and approaches for evaluating the similarity of drinking-water disinfection by-product (DBPs) complex mixtures. Together, the five articles in this series serve as a case study whose techniques will be relevant to assessing similarity for other classes of complex mixtures of environmental chemicals. Schenck et al. (2009) describe the chemistry and mutagenicity of a set of DBP mixtures concentrated from five different drinking-water treatment plants. Bull et al. (2009a, 2009b) describe how the variables that impact the formation of DBP affect the chemical composition and, subsequently, the expected toxicity of the mixture. Feder et al. (2009a, 2009b) evaluate the similarity of DBP mixture concentrates by applying two biostatistical approaches, principal components analysis, and a nonparametric "bootstrap" analysis. Important factors for determining sufficient similarity of DBP mixtures found in this research include disinfectant used; source water characteristics, including the concentrations of bromide and total organic carbon; concentrations and proportions of individual DBPs with known toxicity data on the same endpoint; magnitude of the unidentified fraction of total organic halides; similar toxicity outcomes for whole mixture testing (e.g., mutagenicity); and summary chemical measures such as total trihalomethanes, total haloacetic acids, total haloacetonitriles, and the levels of bromide incorporation in the DBP classes.

Characterization of the Androgen-sensitive MDA-kb2 Cell Line for Assessing Complex Environmental Mixtures, Presentation

EPA Science Inventory

Synthetic and natural steroidal androgens and estrogens and many other non-steroidal endocrine-active compounds commonly occur as complex mixtures in aquatic environments. It is important to understand the potential interactive effects of these mixtures to properly assess their r...

Integrated Disinfection By-Products Research: Assessing Reproductive and Developmental Risks Posed by Complex Disinfection By-Product Mixtures

EPA Science Inventory

This article presents a toxicologically-based risk assessment strategy for identifying the individual components or fractions of a complex mixture that are associated with its toxicity. The strategy relies on conventional component-based mixtures risk approaches such as dose addi...

The inhibitory effect of milk on the absorption of dietary phenolic acids and the change in human plasma antioxidant capacity through a mechanism involving both milk proteins and fats.

PubMed

Zhang, Hao; Jiang, Lu; Guo, Huiyuan; Sun, Jing; Liu, Xianting; Liu, Ruihai; Ding, Qingbo; Ren, Fazheng

2013-07-01

We assessed the effects of milk proteins and fats, alone and in combination, on the absorption of phenolic acids and the change in plasma antioxidant capacity after jujube juice intake in humans. Twenty volunteers received the following four treatments each in a 4 × 4 Latin square design with a minimum 1 week interval: 200 mL of jujube juice plus 200 mL of (1) water; (2) whole milk; (3) skimmed milk; or (4) milk fat. The results showed that skimmed milk extended the time to reach maximum increase of plasma phenolic acids concentrations and plasma antioxidant capacity. However, neither the skimmed milk nor the milk fat had a significant effect on the absorption of phenolic acids. In contrast, whole milk significantly reduced the absorption of phenolic acids and the increase in plasma antioxidant capacity (p < 0.05). In vitro results suggested the formation of complexes during digestion that involved milk proteins, milk fats, and phenolic acids, which were responsible for the inhibitory effect of whole milk. Milk proteins and fats together, but not alone, are responsible for the inhibitory effect of milk on the absorption of phenolic acids and the change in plasma antioxidant capacity. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Is there a negative association between the content of condensed tannins, total phenols, and total tannins of tropical plant extracts and in vitro anthelmintic activity against Haemonchus contortus eggs?

PubMed

Castañeda-Ramírez, G S; Torres-Acosta, J F J; Sandoval-Castro, C A; González-Pech, P G; Parra-Tabla, V P; Mathieu, C

2017-12-01

In vitro studies using plant extracts suggest a relationship between their polyphenol contents and their anthelmintic (AH) activity against Haemonchus contortus. High polyphenol content appears to increase the efficacy of plant extracts against H. contortus as assessed by the larval exsheathment inhibition assay (LEIA) while appearing to reduce the AH efficacy measured using the egg hatch assay (EHA). In addition, some plants lack AH activity. Therefore, the present study investigated the relationship between the contents of condensed tannins (CT), total phenols (TP), and total tannins (TT) in methanol:water extracts (70:30) obtained from ten tropical plant species consumed by small ruminants as well as their AH activity against H. contortus evaluated by LEIA and EHA. Extracts of Acacia collinsii, Lysiloma latisiliquum, Havardia albicans, Senegalia gaumeri, Mimosa bahamensis, Piscidia piscipula, Acacia pennatula, Gymnopodium floribundum, Leucaena leucocephala, and Bunchosia swartziana were examined. Positive correlations were found between the effective concentration 50% (EC 50 ) (EHA) of extracts and their CT (r = 0.6809, P < 0.05, n = 10) and TP (r = 0.9152, P < 0.05, n = 10) content, suggesting that their concentration negatively affected AH activity against eggs. Based on the LEIA, there was no significant association between the EC 50 and the CT, TP, or TT of all extracts evaluated. Thus, if sheep and goats consume a complex feed mixture with high amounts of CT, TP, and TT, it might be difficult to observe an AH effect against H. contortus egg hatching. However, the AH effect upon L 3 establishment might be feasible.

The effect of deodorization on volatile compositions of fucoidan extracted from brown seaweed (Sargassum sp.)

NASA Astrophysics Data System (ADS)

Khalafu, Sharifah Habibah Syed; Mustapha, Wan Aida Wan; Lim, Seng Joe; Maskat, Mohamad Yusof

2016-11-01

Fucoidan is a biologically active polysaccharide that were made up of complex mixture of fucose, sulfate and uronic acid. This study was conducted to identify the volatile compositions of crude fucoidan and deodorized fucoidans extracted from brown seaweed Sargassum sp. (Fsar). The volatile compositions was also compared with a standard commercial fucoidan (Fysk). Fucoidan was extracted from Sargassum sp. originated in coastal area of Indonesia, by using a low pH acid extraction method. Approximately 20 mL of 1% freshly extracted fucoidan was then subjected to deodorization process by using three different method i.e., by treating it with 10 g activated carbon (Fac), 0.4 g ion exchange resin, Amberlite 67 (Fresin) and 2 mL of 1% calcium carbonate (FCaCO3) and incubated for 12 hrs before further analysis. Forty-six volatile compounds were successfully identified in all of the five samples by using Headspace-Solid Phase Microextraction (HS-SPME) and analysed by using Gas Chromatography Mass Spectrometer (GCMS). In Fsar, 72% of the total volatile constituents were identified as aromatic hydrocarbons, 23% hydrocarbons and 5% alcohols. In Fysk, all compounds detected are in group hydrocarbons. In Fsar, all of the compounds identified were classified as odor active compounds which had a contribution to unpleasant odor in fucoidan. After deodorization, 72% of aromatic hydrocarbons detected in Fsar were reported to be absent in all deodorized fucoidans. Both Fresin and FCaCO3 showed a reduction in peak area percentages of phenol, 2,4-bis (1,1-dimethylethyl)- from Fsar (1.30%) to 0.79 and 1.07% respectively. Meanwhile in Fac, no presence of phenol, 2,4-bis (1,1-dimethylethyl) was reported. These findings are essential to propel the advancement of research in deodorization technologies of marine products, especially fucoidans.

Atmospheric pressure photoionization mass spectrometry as a tool for the investigation of the hydrolysis reaction mechanisms of phosphite antioxidants

NASA Astrophysics Data System (ADS)

Papanastasiou, M.; McMahon, A. W.; Allen, N. S.; Johnson, B. W.; Keck-Antoine, K.; Santos, L.; Neumann, M. G.

2008-08-01

The hydrolysis reaction mechanism of phosphite antioxidants is investigated by liquid chromatography-mass spectrometry (LC/MS). The phosphites were chosen because they differed in chemical structure and phosphorus content. Dopant assisted-atmospheric pressure photoionization (DA-APPI) is chosen as the ion source for the ionization of the compounds. In our previous work, DA-APPI was shown to offer an attractive alternative to atmospheric pressure chemical ionization (APCI) since it provided background-ion free mass spectra and higher sensitivity [M. Papanastasiou, et al., Polymer Degradation and Stability 91 (11) (2006) 2675-2682]. In positive ion mode, the molecules are generally detected in their protonated form. In negative ion mode, the phosphites are unstable and only fragment ions are observed; these however, are characteristic of each phosphite and may be used for the identification of the analytes in complex mixtures. The analytes under investigation are exposed to accelerated humid ageing conditions and their hydrolytic pathway and stability is investigated. Different substituents around the phosphorus atom are shown to have a significant effect on the stability of the phosphites, with phenol substituents producing very hydrolytically stable structures. Alkanox P24 and PEP-36 follow a similar hydrolytic pathway via the scission of the first and then the second POphenol bonds, eventually leading to the formation of phenol, phosphorous acid and pentaerythritol as end products. HP-10 exhibits a rather different structure and the products detected suggest scission of either the POhydrocarbon or one of the POphenol bonds. A phenomenon similar to that of autocatalysis is observed for all phosphites and is attributed to the formation of dialkyl phosphites as intermediate products.

Solid-phase extraction of galloyl- and caffeoylquinic acids from natural sources (Galphimia glauca and Arnicae flos) using pure zirconium silicate and bismuth citrate powders as sorbents inside micro spin columns.

PubMed

Hussain, Shah; Schönbichler, Stefan A; Güzel, Yüksel; Sonderegger, Harald; Abel, Gudrun; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

2013-10-01

Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(®) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents. Copyright © 2013 Elsevier B.V. All rights reserved.

An Implicit Finite Difference Solution to the Viscous Radiating Shock Layer with Strong Blowing. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Garrett, L. B.

1971-01-01

An implicit finite difference scheme is developed for the fully coupled solution of the viscous radiating stagnation line equations, including strong blowing. Solutions are presented for both air injection and carbon phenolic ablation products injection into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized.

[Characteristics of the composition of Caucasian blackberry (Rubus caucasicus L.) leaves as a raw material for tea production].

PubMed

Melkadze, R G; Chichkovani, N Sh; Kakhniashvili, E Z

2008-01-01

The composition of Caucasian blackberry (Rubus caucasicus L.) six-leaf shoot was studied. The weight of the stem reached 50% of the total weight of the shoot. The content of moisture, extractive substances, and phenolic compounds was minimal at the beginning and end of the vegetation season. Phenolic compounds were represented by catechins, leukoanthocyanidins, and flavonols. The most abundant phenolic compounds in all parts of the blackberry shoot were leukoanthocyanidins, which accounted for approximately 50% of all compounds of this class. Phenolic compounds accumulated most actively in July and August. The average content of free amino acids in the blackberry leaf during the vegetation season was 26.68 mg/g. Among the total free amino acids, eleven have been identified, five of which proved to be essential (His, Arg, Met, Leu, Val) and accounted for 40% of the total amount of amino acids. The oxidability of acetone extract of the blackberry leaf was compared to the oxidability of total phenolic compounds and tea tannin. The tea product obtained from the blackberry leaf had good organoleptic parameters and a saturated extractive complex.

Preventing False Negatives for Histochemical Detection of Phenolics and Lignins in PEG-Embedded Plant Tissues

PubMed Central

Ferreira, Bruno G.; Falcioni, Renan; Guedes, Lubia M.; Avritzer, Sofia C.; Antunes, Werner C.; Souza, Luiz A.; Isaias, Rosy M.S.

2016-01-01

Polyethylene glycol (PEG) is a low-cost and advantageous embedding medium, which maintains the majority of cell contents unaltered during the embedding process. Some hard or complex plant materials are better embedded in PEG than in other usual embedding media. However, the histochemical tests for phenolics and lignins in PEG-embedded plant tissues commonly result in false negatives. We hypothesize that these false negatives should be prevented by the use of distinct fixatives, which should avoid the bonds between PEG and phenols. Novel protocols for phenolics and flavanols detection are efficiently tested, with fixation of the samples in ferrous sulfate and formalin or in caffeine and sodium benzoate, respectively. The differentiation of lignin types is possible in safranin-stained sections observed under fluorescence. The Maule’s test faultlessly distinguishes syringyl-rich from guaiacyl- and hydroxyphenyl-rich lignins in PEG-embedded material under light microscopy. Current hypothesis is corroborated, that is, the adequate fixation solves the false-negative results, and the new proposed protocols fill up some gaps on the detection of phenolics and lignins. PMID:28117630

Biogas production from pretreated coffee-pulp waste by mixture of cow dung and rumen fluid in co-digestion

NASA Astrophysics Data System (ADS)

Juliastuti, Sri Rachmania; Widjaja, Tri; Altway, Ali; Iswanto, Toto

2017-05-01

Coffee is an excellent commodity in Indonesia that has big problem in utilizing its wastes. As the solution, the abundant coffee pulp waste from processing of coffee bean industry has been used as a substrate of biogas production. Coffee pulp waste (CPW) was approximately 48% of total weight, consisting 42% of the coffee pulp and 6% of the seed coat. CPW holds good composition as biogas substrate that is consist of cellulose (63%), hemicellulose (2.3%) and protein (11.5%). Methane production from coffee pulp waste still has much problems because of toxic chemicals content such as caffeine, tannin, and total phenol which can inhibit the biogas production. In this case, CPW was pretreated by ethanol/water (50/50, v/v) at room temperature to remove those inhibitors. This study was to compare the methane production by microbial consortium of cow dung and rumen fluid mixture coffee pulp waste as a substrate with and without pretreatment. The pretreated CPW was fermented with mixture of Cow Dung (CD) and Rumen Fluid (RF) in anaerobic co-digestion for 30 days at mesophilic temperature (30-40°C) and the pH was maintained from 6.8 to 7.2 on a reactor with working volume of 3.6 liters. There were two reactors with each containing the mixture of CPW without pretreatment, cow dung and rumen fluid (CD+RF+CPW) and then compared with the CPW with pretreatment (CD+RF+PCPW) reactor. The measured parameters included the decreasing of inhibitor compound concentration, Volatile Fatty Acids (VFAs), Chemical Oxygen Demand (COD), Total Solid (TS), Volatile Solid (VS), Methane and the Calorific value of gas (heating value) were studied as well. The result showed a decrease in inhibitor component concentration due to methanol pretreatment was 90% of caffeine; 78% of polyphenols (total phenol) and 66% of tannins. The highest methane content in biogas was produced in CD+RF+PCPW digester with concentration amounted of 44.56% with heating value of 27,770 BTU/gal.

Experimental and modeling studies of a biofuel surrogate compound: laminar burning velocities and jet-stirred reactor measurements of anisole

DOE PAGES

Wagnon, Scott W.; Thion, Sebastien; Nilsson, Elna J. K.; ...

2017-11-23

Lignocellulosic biomass is a promising alternative fuel source which can promote energy security, reduce greenhouse gas emissions, and minimize fuel consumption when paired with advanced combustion strategies. Pyrolysis is used to convert lignocellulosic biomass into a complex mixture of phenolic-rich species that can be used in a transportation fuel. Anisole (or methoxybenzene) can be used as a surrogate to represent these phenolic-rich species. Anisole also has attractive properties as a fuel component for use in advanced spark-ignition engines because of its high blending research octane number of 120. Presented in the current work are new measurements of laminar burning velocities,more » jet-stirred reactor (JSR) speciation of anisole/O 2/N 2 mixtures, and the development and validation of a detailed chemical kinetic mechanism for anisole. Homogeneous, steady state, fixed gas temperature, perfectly stirred reactor CHEMKIN simulations were used to validate the mechanism against the current JSR measurements and published JSR experiments from CNRS-Nancy. Pyrolysis and oxidation simulations were based on the experimental reactant compositions and thermodynamic state conditions including P = 1 bar and T = 675–1275 K. The oxidation compositions studied in this work span fuel-lean (φ = 0.5), stoichiometric, and fuel rich (φ = 2.0) equivalence ratios. Laminar burning velocities were measured on a heat flux stabilized burner at an unburnt T = 358 K, P = 1 bar and simulated using the CHEMKIN premixed laminar flame speed module. Ignition delay times of anisole were then simulated at conditions relevant to advanced combustion strategies. Current laminar burning velocity measurements and predicted ignition delay times were compared to gasoline components (e.g., n-heptane, iso-octane, and toluene) and gasoline surrogates to highlight differences and similarities in behavior. Reaction path analysis and sensitivity analysis were used to explain the pathways relevant to the current studies. Under pyrolysis and oxidative conditions, unimolecular decomposition of anisole to phenoxy radicals and methyl radicals was found to be important due to the relatively low bond strength between the oxygen and methyl group, ~65 kcal/mol. Finally, reactions of these abundant phenoxy radicals with O 2 were found to be critical to accurately reproduce anisole's reactivity.« less

Experimental and modeling studies of a biofuel surrogate compound: laminar burning velocities and jet-stirred reactor measurements of anisole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagnon, Scott W.; Thion, Sebastien; Nilsson, Elna J. K.

Lignocellulosic biomass is a promising alternative fuel source which can promote energy security, reduce greenhouse gas emissions, and minimize fuel consumption when paired with advanced combustion strategies. Pyrolysis is used to convert lignocellulosic biomass into a complex mixture of phenolic-rich species that can be used in a transportation fuel. Anisole (or methoxybenzene) can be used as a surrogate to represent these phenolic-rich species. Anisole also has attractive properties as a fuel component for use in advanced spark-ignition engines because of its high blending research octane number of 120. Presented in the current work are new measurements of laminar burning velocities,more » jet-stirred reactor (JSR) speciation of anisole/O 2/N 2 mixtures, and the development and validation of a detailed chemical kinetic mechanism for anisole. Homogeneous, steady state, fixed gas temperature, perfectly stirred reactor CHEMKIN simulations were used to validate the mechanism against the current JSR measurements and published JSR experiments from CNRS-Nancy. Pyrolysis and oxidation simulations were based on the experimental reactant compositions and thermodynamic state conditions including P = 1 bar and T = 675–1275 K. The oxidation compositions studied in this work span fuel-lean (φ = 0.5), stoichiometric, and fuel rich (φ = 2.0) equivalence ratios. Laminar burning velocities were measured on a heat flux stabilized burner at an unburnt T = 358 K, P = 1 bar and simulated using the CHEMKIN premixed laminar flame speed module. Ignition delay times of anisole were then simulated at conditions relevant to advanced combustion strategies. Current laminar burning velocity measurements and predicted ignition delay times were compared to gasoline components (e.g., n-heptane, iso-octane, and toluene) and gasoline surrogates to highlight differences and similarities in behavior. Reaction path analysis and sensitivity analysis were used to explain the pathways relevant to the current studies. Under pyrolysis and oxidative conditions, unimolecular decomposition of anisole to phenoxy radicals and methyl radicals was found to be important due to the relatively low bond strength between the oxygen and methyl group, ~65 kcal/mol. Finally, reactions of these abundant phenoxy radicals with O 2 were found to be critical to accurately reproduce anisole's reactivity.« less

Mixture and odorant processing in the olfactory systems of insects: a comparative perspective.

PubMed

Clifford, Marie R; Riffell, Jeffrey A

2013-11-01

Natural olfactory stimuli are often complex mixtures of volatiles, of which the identities and ratios of constituents are important for odor-mediated behaviors. Despite this importance, the mechanism by which the olfactory system processes this complex information remains an area of active study. In this review, we describe recent progress in how odorants and mixtures are processed in the brain of insects. We use a comparative approach toward contrasting olfactory coding and the behavioral efficacy of mixtures in different insect species, and organize these topics around four sections: (1) Examples of the behavioral efficacy of odor mixtures and the olfactory environment; (2) mixture processing in the periphery; (3) mixture coding in the antennal lobe; and (4) evolutionary implications and adaptations for olfactory processing. We also include pertinent background information about the processing of individual odorants and comparative differences in wiring and anatomy, as these topics have been richly investigated and inform the processing of mixtures in the insect olfactory system. Finally, we describe exciting studies that have begun to elucidate the role of the processing of complex olfactory information in evolution and speciation.

Phenol and terpene quenching of singlet- and triplet-excited states of riboflavin in relation to light-struck flavor formation in beer.

PubMed

Cardoso, Daniel R; Olsen, Karsten; Møller, Jens K S; Skibsted, Leif H

2006-07-26

Phenolic compounds present in beer were shown by fluorescence spectroscopy and laser flash photolysis to deactivate both singlet- and triplet-excited states of riboflavin with bimolecular rate constants close to the diffusion control ranging from 2.8x10(9) to 1.1x10(10) M-1 s-1 and from 1.1x10(9) to 2.6x10(9) M-1 s-1, respectively. Enthalpies of activation were low (up to 33.2 kJ mol-1), and entropies of activation were positive, ranging from 17 to 92 J mol-1 K-1, as derived from temperature dependence, indicating a compensation effect. From a Stern-Volmer analysis of the singlet-excited riboflavin quenching by phenols it was found that high amounts of phenolic compounds (>0.3 M) would be needed to hinder triplet-excited riboflavin generation. On the other hand, a phenolic content of 0.36 mM is likely to quench 90% of the triplet-excited state. Phenol photodegradation was found to be complex, and using ESI-MS analysis it was not possible to identify specific photooxidation products of the phenolic compounds; only the photoproducts of riboflavin could be detected and structurally assigned. The rate of reaction of triplet-excited riboflavin with phenolic compounds in acetonitrile/citrate buffer (pH 4.6, 10 mM) is 550 times faster than the reaction with iso-alpha-acids from hops, indicating that triplet-excited quenchers such as phenols may be involved in the early steps in light-struck flavor formation in beer through radical formation. Terpenes present in herb-flavored beers were found to be nonreactive toward singlet- and triplet-excited-state riboflavin, and any protection depends on other mechanisms.

Reversed phase liquid chromatography with UV absorbance and flame ionization detection using a water mobile phase and a cyano propyl stationary phase Analysis of alcohols and chlorinated hydrocarbons.

PubMed

Quigley, W W; Ecker, S T; Vahey, P G; Synovec, R E

1999-10-01

The development of liquid chromatography with a commercially available cyano propyl stationary phase and a 100% water mobile phase is reported. Separations were performed at ambient temperature, simplifying instrumental requirements. Excellent separation efficiency using a water mobile phase was achieved, for example N=18 800, or 75 200 m(-1), was obtained for resorcinol, at a retention factor of k'=4.88 (retention time of 9.55 min at 1 ml min(-1) for a 25 cmx4.6 mm i.d. column, packed with 5 mum diameter particles with the cyano propyl stationary phase). A separation via reversed phase liquid chromatography (RP-LC) with a 100% water mobile phase of six phenols and related compounds was compared to a separation of the same compounds by traditional RP-LC, using octadecylsilane (ODS), i.e. C18, bound to silica and an aqueous mobile phase modified with acetonitrile. Nearly identical analysis time was achieved for the separation of six phenols and related compounds using the cyano propyl stationary phase with a 100% water mobile phase, as compared to traditional RP-LC requiring a relatively large fraction of organic solvent modifier in the mobile phase (25% acetonitrile:75% water). Additional understanding of the retention mechanism with the 100% water mobile phase was obtained by relating measured retention factors of aliphatic alcohols, phenols and related compounds, and chlorinated hydrocarbons to their octanol:water partition coefficients. The retention mechanism is found to be consistent with a RP-LC mechanism coupled with an additional retention effect due to residual hydroxyl groups on the cyano propyl stationary phase. Advantages due to a 100% water mobile phase for the chemical analysis of alcohol mixtures and chlorinated hydrocarbons are reported. By placing an absorbance detector in-series and preceding a novel drop interface to a flame ionization detector (FID), selective detection of a separated mixture of phenols and related compounds and aliphatic alcohols is achieved. The compound class of aliphatic alcohols is selectively and sensitively detected by the drop interface/FID, and the phenols and related compounds are selectively and sensitively detected by absorbance detection at 200 nm. The separation and detection of chlorinated hydrocarbons in a water sample matrix further illustrated the advantages of this methodology. The sensitivity and selectivity of the FID signal for the chlorinated hydrocarbons are significantly better than absorbance detection, even at 200 nm. This methodology is well suited to continuous and automated monitoring of water samples. The applicability of samples initially in an organic solvent matrix is explored, since an organic sample matrix may effect retention and efficiency. Separations in acetonitrile and isopropyl alcohol sample matrices compared well to separations with a water sample matrix.

Potentiometric study of binary complexes of 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride with some lanthanide ions in aqueous and mixed solutions

NASA Astrophysics Data System (ADS)

Sharma, S. S.; Kadia, M. V.

2014-12-01

The complexation of lanthanide ions (Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, and Dy3+) with 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride was studied at different temperatures and different ionic strengths in aqueous solutions by Irving-Rossotti pH titration technique. Stepwise calculation, PKAS and BEST Fortran IV computer programs were used for determination of proton-ligand and metal-ligand stability constants. The formation of species like MA, MA2, and MA(OH) is considered in SPEPLOT. Thermodynamic parameters of complex formation (Δ G, Δ H, and Δ S) are also evaluated. Negative Δ G and Δ H values indicate that complex formation is favourable in these experimental conditions. The stability of complexes is also studied at in different solvent-aqueous (vol/vol). The stability series of lanthanide complexes has shown to have the "gadolinium break." Stability of complexes decreases with increase in ionic strength and temperature. Effect of systematic errors like effect of dissolved carbon dioxide, concentration of alkali, concentration of acid, concentration of ligand and concentration of metal have also been explained.

Defence syndromes in lodgepole - whitebark pine ecosystems relate to degree of historical exposure to mountain pine beetles.

PubMed

Raffa, Kenneth F; Mason, Charles J; Bonello, Pierluigi; Cook, Stephen; Erbilgin, Nadir; Keefover-Ring, Ken; Klutsch, Jennifer G; Villari, Caterina; Townsend, Philip A

2017-09-01

Warming climate is allowing tree-killing bark beetles to expand their ranges and access naïve and semi-naïve conifers. Conifers respond to attack using complex mixtures of chemical defences that can impede beetle success, but beetles exploit some compounds for host location and communication. Outcomes of changing relationships will depend on concentrations and compositions of multiple host compounds, which are largely unknown. We analysed constitutive and induced chemistries of Dendroctonus ponderosae's primary historical host, Pinus contorta, and Pinus albicaulis, a high-elevation species whose encounters with this beetle are transitioning from intermittent to continuous. We quantified multiple classes of terpenes, phenolics, carbohydrates and minerals. Pinus contorta had higher constitutive allocation to, and generally stronger inducibility of, compounds that resist these beetle-fungal complexes. Pinus albicaulis contained higher proportions of specific monoterpenes that enhance pheromone communication, and lower induction of pheromone inhibitors. Induced P. contorta increased insecticidal and fungicidal compounds simultaneously, whereas P. albicaulis responses against these agents were inverse. Induced terpene accumulation was accompanied by decreased non-structural carbohydrates, primarily sugars, in P. contorta, but not P. albicaulis, which contained primarily starches. These results show some host species with continuous exposure to bark beetles have more thoroughly integrated defence syndromes than less-continuously exposed host species. © 2017 John Wiley & Sons Ltd.

Application of the high throughput Attagene Factorial TM platform to environmental monitoring: Characterizing complex, environmental mixtures

EPA Science Inventory

Bioassays can be employed to evaluate the integrated effects of complex mixtures of both known and unidentified contaminants present in environmental samples. However, such methods have typically focused on one or a few pathways despite the fact that the chemicals in a mixture ma...

Measurement of the complex permittivity of dry rocks and minerals: application of polythene dilution method and Lichtenecker's mixture formulae

NASA Astrophysics Data System (ADS)

Zheng, Yongchun; Wang, Shijie; Feng, Junming; Ouyang, Ziyuan; Li, Xiongyao

2005-12-01

The complex permittivity of dry rocks and minerals varies over a very wide range, even within a sample there are variation at different temperatures and frequencies. Most rocks and minerals are inhomogeneous materials, therefore, most of the present methods of dielectric measurement designed for artificial homogeneous materials are not suitable for rocks and minerals. The resonant cavity perturbation (RCP) method is a reliable and simple technique to determine the complex permittivity of dielectric materials in the GHz range, and this method is also used extensively. However, the traditional RCP method is sensitive to the measurement of low dielectric constant (ɛ') and low loss factor (ɛ'' or tanδ) materials. The complex permittivity of most dry rocks and minerals exceeds the span vibration of the RCP method, and cannot be measured by the RCP method directly. This paper proposes a new method to measure the complex permittivity of dry rocks and minerals with the RCP method incorporated in the application of polythene (PE) dilution method and Lichtenecker's mixture formulae. Dry rocks and minerals were ground into fine powder. The powder of rocks and minerals was mixed with polythene powder in a definite volume per cent. The mixture was heated and pressed into a thin circular slice. The slice was processed into a small rectangular strip sample, the size of which was fitted to the demands of the RCP method. The complex permittivity of the strip was obtained by the RCP method. The relationship between the dielectric properties of the two-phase mixture and those of each phase in the mixture can be expressed by Lichtenecker's mixture formula. Thus the complex permittivity of dry rocks and minerals can be calculated from the complex permittivity of the mixture in case the complex permittivity of polythene is known. The presented method was verified by measurements of reference materials of various known complex permittivity and other reliable dielectric measurement methods. The results of the experiment showed that this new method is of high accuracy, small sample requirement, and convenient application. Moreover, the complex permittivity of rocks and minerals measured by this method is more reliable than the direct dielectric measurement of rocks or minerals without application of the polythene dilution method and Lichtenecker's mixture formulae.

THE GENOTOXICITY OF PRIORITY POLYCYCLIC AROMATIC HYDROCARBONS IN COMPLEX MIXTURES

EPA Science Inventory

Risk assessment of complex environmental samples suffers from difficulty in identifying toxic components, inadequacy of available toxicity data, and a paucity of knowledge about the behavior of geno(toxic) substances in complex mixtures. Lack of information about the behavior of ...

Iron deficiency enhances bioactive phenolics in lemon juice.

PubMed

Mellisho, Carmen D; González-Barrio, Rocío; Ferreres, Federico; Ortuño, María F; Conejero, Wenceslao; Torrecillas, Arturo; García-Mina, José M; Medina, Sonia; Gil-Izquierdo, Angel

2011-09-01

This study was designed to describe the phenolic status of lemon juice obtained from fruits of lemon trees differing in iron (Fe) nutritional status. Three types of Fe(III) compound were used in the experiment, namely a synthetic chelate and two complexes derived from natural polymers of humic and lignine nature. All three Fe(III) compounds were able to improve the Fe nutritional status of lemon trees, though to different degrees. This Fe(III) compound effect led to changes in the polyphenol content of lemon juice. Total phenolics were decreased (∼33% average decrease) and, in particular, flavanones, flavones and flavonols were affected similarly. Iron-deficient trees showed higher phenolic contents than Fe(III) compound-treated trees, though Fe deficiency had negative effects on the yield and visual quality of fruits. However, from a human nutritional point of view and owing to the health-beneficial properties of their bioavailable phenolic compounds, the nutritional quality of fruits of Fe-deficient lemon trees in terms of phenolics was higher than that of fruits of Fe(III) compound-treated lemon trees. Moreover, diosmetin-6,8-di-C-glucoside in lemon juice can be used as a marker for correction of Fe deficiency in lemon trees. Copyright © 2011 Society of Chemical Industry.

Ultra‐high performance supercritical fluid chromatography of lignin‐derived phenols from alkaline cupric oxide oxidation

PubMed Central

Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta

2016-01-01

Traditional chromatographic methods for the analysis of lignin‐derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra‐high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin‐derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5–2.5 μM, a limit of quantification of 2.5–5.0 μM, and a dynamic range of 5.0–2.0 mM (R 2 > 0.997). The new ultra‐high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin‐derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin‐derived phenols in complex environmental samples. PMID:27452148

Intestinal Permeability and Cellular Antioxidant Activity of Phenolic Compounds from Mango (Mangifera indica cv. Ataulfo) Peels.

PubMed

Pacheco-Ordaz, Ramón; Antunes-Ricardo, Marilena; Gutiérrez-Uribe, Janet A; González-Aguilar, Gustavo A

2018-02-08

Mango ( Mangifera indica cv. Ataulfo) peel contains bound phenolics that may be released by alkaline or acid hydrolysis and may be converted into less complex molecules. Free phenolics from mango cv. Ataulfo peel were obtained using a methanolic extraction, and their cellular antioxidant activity (CAA) and permeability were compared to those obtained for bound phenolics released by alkaline or acid hydrolysis. Gallic acid was found as a simple phenolic acid after alkaline hydrolysis along with mangiferin isomers and quercetin as aglycone and glycosides. Only gallic acid, ethyl gallate, mangiferin, and quercetin were identified in the acid fraction. The acid and alkaline fractions showed the highest CAA (60.5% and 51.5%) when tested at 125 µg/mL. The value of the apparent permeability coefficient (Papp) across the Caco-2/HT-29 monolayer of gallic acid from the alkaline fraction was higher (2.61 × 10 -6 cm/s) than in the other fractions and similar to that obtained when tested pure (2.48 × 10 -6 cm/s). In conclusion, mango peels contain bound phenolic compounds that, after their release, have permeability similar to pure compounds and exert an important CAA. This finding can be applied in the development of nutraceuticals using this important by-product from the mango processing industry.

Optimization of a new mobile phase to know the complex and real polyphenolic composition: towards a total phenolic index using high-performance liquid chromatography.

PubMed

Tsao, Rong; Yang, Raymond

2003-11-07

An HPLC method is reported for the separation and quantification of five major polyphenolic groups found in fruits and related products: single ring phenolic acids (hydroxybenzoic acid and hydroxycinnamic acid derivatives), flavan-3-ols, flavonols, anthocyanins, and dihydrochalcones. A binary mobile phase consisting of 6% acetic acid in 2 mM sodium acetate aqueous solution (v/v, final pH 2.55) (solvent A) and acetonitrile (solvent B) was used. The use of sodium acetate was new and key to the near baseline separation of 25 phenolics commonly found in fruits. A photodiode array detector was used and data were collected at four wavelengths (280, 320, 360, and 520 nm). This method was sensitive and gave good separation of polyphenolics in apple, cherry, strawberry, blackberry, grape, apple juice, and a processing by-product. The improved separation has led to better understanding of the polyphenolic profiles of these fruits. Individual as well as total phenolic content was obtained, and the latter was close to and correlated well with that obtained by the Folin-Ciocalteu method (FC). The HPLC data can be used as a total phenolic index (TPI) for quantification of fruit phenolics, which is advantageous over the FC because it has more information on individual compounds.

Detection of Total Phenol in Green and Black Teas by Flow Injection System and Unmodified Screen Printed Electrode

PubMed Central

de Mattos, Ivanildo Luiz; Zagal, José Heraclito

2010-01-01

A flow injection system using an unmodified gold screen-printed electrode was employed for total phenol determination in black and green teas. In order to avoid passivation of the electrode surface due to the redox reaction, preoxidation of the sample was realized by hexacyanoferrate(III) followed by addition of an EDTA solution. The complex formed in the presence of EDTA minimizes or avoids polymerization of the oxidized phenols. The previously filtered tea sample and hexacyanoferrate(III) reagent were introduced simultaneously into two-carrier streams producing two reproducible zones. At confluence point, the pre-oxidation of the phenolic compounds occurs while this zone flows through the coiled reactor and receives the EDTA solution before phenol detection. The consumption of ferricyanide was monitorized at 360 mV versus Ag/AgCl and reflected the total amount of phenolic compounds present in the sample. Results were reported as gallic acid equivalents (GAEs). The proposed system is robust, versatile, environmentally-friendly (since the reactive is used only in the presence of the sample), and allows the analysis of about 35–40 samples per hour with detection limit = 1 mg/L without the necessity for surface cleaning after each measurement. Precise results are in agreement with those obtained by the Folin-Ciocalteu method. PMID:21461407

pH-Responsive Capsules Engineered from Metal-Phenolic Networks for Anticancer Drug Delivery.

PubMed

Ping, Yuan; Guo, Junling; Ejima, Hirotaka; Chen, Xi; Richardson, Joseph J; Sun, Huanli; Caruso, Frank

2015-05-06

A new class of pH-responsive capsules based on metal-phenolic networks (MPNs) for anticancer drug loading, delivery and release is reported. The fabrication of drug-loaded MPN capsules, which is based on the formation of coordination complexes between natural polyphenols and metal ions over a drug-coated template, represents a rapid strategy to engineer robust and versatile drug delivery carriers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construction of an evaluation and selection system of emergency treatment technology based on dynamic fuzzy GRA method for phenol spill

NASA Astrophysics Data System (ADS)

Zhao, Jingjing; Yu, Lean; Li, Lian

2017-05-01

There is often a great deal of complexity, fuzziness and uncertainties of the chemical contingency spills. In order to obtain the optimum emergency disposal technology schemes as soon as the chemical pollution accident occurs, the technique evaluation system was developed based on dynamic fuzzy GRA method, and the feasibility of the proposed methods has been tested by using a emergency phenol spill accidence occurred in highway.

Assessment of health effects in epidemiologic studies of air pollution.

PubMed Central

Samet, J M; Speizer, F E

1993-01-01

As we increasingly recognize the complexity of the pollutants in indoor and outdoor microenvironments, a broad array of inhaled mixtures has assumed scientific, public health, and regulatory importance. Few adverse effects of environmental pollutants are specific, that is, uniquely associated with a single agent; the adverse effects that might be considered in an investigation of the consequences of exposure to an inhaled complex mixture are generally nonspecific. In the context of this paper, we will refer to binary mixtures as complex, though we realize that a more precise definition of complexity would restrict the term to mixtures of three or more constituents. Their causes potentially include not only pollutant exposures through the medium of inhaled air but other environmental agents, such as infectious organisms and radiation, and inherent characteristics of the exposed persons, such as atopy. We review the outcome measures that have been used in epidemiologic studies of the health effects of single pollutants and complex mixtures. Some of these outcome measures have been carefully standardized, whereas others need similar standardization and modification to improve sensitivity and specificity for investigating the health effects of air pollution. PMID:8206024

Molecular identification of organic compounds in atmospheric complex mixtures and relationship to atmospheric chemistry and sources.

PubMed

Mazurek, Monica A

2002-12-01

This article describes a chemical characterization approach for complex organic compound mixtures associated with fine atmospheric particles of diameters less than 2.5 m (PM2.5). It relates molecular- and bulk-level chemical characteristics of the complex mixture to atmospheric chemistry and to emission sources. Overall, the analytical approach describes the organic complex mixtures in terms of a chemical mass balance (CMB). Here, the complex mixture is related to a bulk elemental measurement (total carbon) and is broken down systematically into functional groups and molecular compositions. The CMB and molecular-level information can be used to understand the sources of the atmospheric fine particles through conversion of chromatographic data and by incorporation into receptor-based CMB models. Once described and quantified within a mass balance framework, the chemical profiles for aerosol organic matter can be applied to existing air quality issues. Examples include understanding health effects of PM2.5 and defining and controlling key sources of anthropogenic fine particles. Overall, the organic aerosol compositional data provide chemical information needed for effective PM2.5 management.

Copper(II) and zinc(II) dinuclear enzymes model compounds: The nature of the metal ion in the biological function

NASA Astrophysics Data System (ADS)

Ferraresso, L. G.; de Arruda, E. G. R.; de Moraes, T. P. L.; Fazzi, R. B.; Da Costa Ferreira, A. M.; Abbehausen, C.

2017-12-01

First series transition metals are used abundantly by nature to perform catalytic transformations of several substrates. Furthermore, the cooperative activity of two proximal metal ions is common and represents a highly efficient catalytic system in living organisms. In this work three dinuclear μ-phenolate bridged metal complexes were prepared with copper(II) and zinc(II), resulting in a ZnZn, CuCu and CuZn with the ligand 2-ethylaminodimethylamino phenol (saldman) as model compounds of superoxide dismutase (CuCu and CuZn) and metallo-β-lactamases (ZnZn). Metals are coordinated in a μ-phenolate bridged symmetric system. Cu(II) presents a more distorted structure, while zinc is very symmetric. For this reason, [CuCu(saldman)] shows higher water solubility and also higher lability of the bridge. The antioxidant and hydrolytic beta-lactamase-like activity of the complexes were evaluated. The lability of the bridge seems to be important for the antioxidant activity and is suggested to because of [CuCu(saldman)] presents a lower antioxidant capacity than [CuZn(saldman)], which showed to present a more stable bridge in solution. The hydrolytic activity of the bimetallic complexes was assayed using nitrocefin as substrate and showed [ZnZn(saldman)] as a better catalyst than the Cu(II) analog. The series demonstrates the importance of the nature of the metal center for the biological function and how the reactivity of the model complex can be modulated by coordination chemistry.

Determination of phenolic compounds using spectral and color transitions of rhodium nanoparticles.

PubMed

Gatselou, Vasiliki; Christodouleas, Dionysios C; Kouloumpis, Antonios; Gournis, Dimitrios; Giokas, Dimosthenis L

2016-08-17

This work reports a new approach for the determination of phenolic compounds based on their interaction with citrate-capped rhodium nanoparticles. Phenolic compounds (i.e., catechins, gallates, cinnamates, and dihydroxybenzoic acids) were found to cause changes in the size and localized surface plasmon resonance of rhodium nanoparticles, and therefore, give rise to analyte-specific spectral and color transitions in the rhodium nanoparticle suspensions. Upon reaction with phenolic compounds (mainly dithydroxybenzoate derivatives, and trihydroxybenzoate derivatives), new absorbance peaks at 350 nm and 450 nm were observed. Upon reaction with trihydroxybenzoate derivatives, however, an additional absorbance peak at 580 nm was observed facilitating the speciation of phenolic compounds in the sample. Both absorbance peaks at 450 nm and 580 nm increased with increasing concentration of phenolic compounds over a linear range of 0-500 μM. Detection limits at the mid-micromolar levels were achieved, depending on the phenolic compound involved, and with satisfactory reproducibility (<7.3%). On the basis of these findings, two rhodium nanoparticles-based assays for the determination of the total phenolic content and total catechin content were developed and applied in tea samples. The obtained results correlated favorably with commonly used methods (i.e., Folin-Ciocalteu and aluminum complexation assay). Not the least, the finding that rhodium nanoparticles can react with analytes and exhibit unique localized surface plasmon resonance bands in the visible region, can open new opportunities for developing new optical and sensing analytical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Lignin geochemistry of a Late Quaternary sediment core from Lake Washington

NASA Astrophysics Data System (ADS)

Hedges, John I.; Ertel, John R.; Leopold, Estella B.

1982-10-01

Long-term lignin stability and paleovegetation patterns were investigated using CuO oxidation products of sediments from an 11 m core of Late Quaternary sediment collected from the mid-basin of Lake Washington, Washington State. Relatively constant yields of lignin-derived phenols (normalized to organic carbon) from the entire core indicate minimal in situ lignin degradation over the last 13,000 years. Compositional patterns within the phenolic suite and increased corresponding yields from baseextracted sediments indicate that sedimentary lignins are present predominantly as well preserved plant tissue fragments. Abundance patterns of vanillyl, syringyl, and cinnamyl phenols record four distinct sequences within the core characterized by: (a) high concentrations of gymnosperm wood in a basal horizon of glacial flour, 11-10 m; (b) an essentially pure mixture of nonwoody angiosperm tissues in late Pleistocene sediments, 10-8 m; (c) relatively high concentrations of angiosperm woods in the bottom half of a limnic peat sequence deposited approximately 10,000-7,000 years B.P., 8-4 m; and (d) a progressive enrichment in gymnosperm woods at the expense of angiosperm woods over the last 7,000 years in the upper limnic peat, 4-0 m. Vascular plant tissues account for less than half the total sedimentary organic carbon throughout the core.

Enhanced Bioaccessibility of Crocetin Sugar Esters from Saffron in Infusions Rich in Natural Phenolic Antioxidants.

PubMed

Ordoudi, Stella A; Kyriakoudi, Anastasia; Tsimidou, Maria Z

2015-09-25

The present study aims to examine whether and to what extent the bioaccessibility of the major saffron apocarotenoids, namely crocetin sugar esters (CRTSEs), is affected by the presence of strong water-soluble antioxidants, ingredients of the herbs found in commercial tea blends with saffron. An in vitro digestion model was applied to infusions from these products to investigate the possible changes. All of the studied infusions were rich in total phenols (9.9-22.5 mg caffeic acid equivalents/100 mg dry infusion) and presented strong DPPH radical scavenging activity regardless of the composition of the corresponding herbal blends. RP-HPLC-DAD and LC-MS analysis enabled the grouping of the infusions into hydroxycinnamic acid-rich and in flavan-3-ol-rich ones. CRTSEs in herbal tea infusions were found to be significantly more bioaccessible (66.3%-88.6%) than those in the reference saffron infusion (60.9%). The positive role of strong phenolic antioxidants (caffeic acid, rosmarinic acid) on the stability of CRTSEs was also evidenced in model binary mixtures. On the contrary, cinnamic acid, exerting no antioxidant activity, did not have such an effect. Our findings suggest that strong radical scavengers may protect the crocetin sugar esters from oxidation during digestion when present in excess.

Structural dissection of Shewanella oneidensis old yellow enzyme 4 bound to a Meisenheimer complex and (nitro)phenolic ligands.

PubMed

Elegheert, Jonathan; Brigé, Ann; Van Beeumen, Jozef; Savvides, Savvas N

2017-10-01

Shewanella oneidensis, a Gram-negative γ-proteobacterium with an extensive redox capacity, possesses four old yellow enzyme (OYE) homologs. Of these, Shewanella yellow enzyme 4 (SYE4) is implicated in resistance to oxidative stress. Here, we present a series of high-resolution crystal structures for SYE4 in the oxidized and reduced states, and in complex with phenolic ligands and the nitro-aromatic explosive picric acid. The structures unmask new features, including the identification of a binding platform for long-chain hydrophobic molecules. Furthermore, we present the first structural observation of a hydride-Meisenheimer complex of picric acid with a flavoenzyme. Overall, our study exposes the binding promiscuity of SYE4 toward a variety of electrophilic substrates and is consistent with a general detoxification function for SYE4. © 2017 Federation of European Biochemical Societies.

Analysis of food polyphenols by ultra high-performance liquid chromatography coupled to mass spectrometry: an overview.

PubMed

Motilva, Maria-José; Serra, Aida; Macià, Alba

2013-05-31

Phenolic compounds, which are widely distributed in plant-derived foods, recently attracted much attention due to their health benefits, so their determination in food samples is a topic of increasing interest. In the last few years, the development of chromatographic columns packed with sub-2μm particles and the modern high resolution mass spectrometry (MS) have opened up new possibilities for improving the analytical methods for complex sample matrices, such as ingredients, foods and biological samples. In addition, they have emerged as an ideal tool for profiling complex samples due to its speed, efficiency, sensitivity and selectivity. The present review addresses the use of the improved liquid chromatography (LC), ultra-high performance LC (UHPLC), coupled to MS or tandem MS (MS/MS) as the detector system for the determination of phenolic compounds in food samples. Additionally, the different strategies to extract, quantify the phenolic compounds and to reduce the matrix effect (%ME) are also reviewed. Finally, a briefly outline future trends of UHPLC-MS methods is commented. Copyright © 2013 Elsevier B.V. All rights reserved.

Rapid phenolic O-glycosylation of small molecules and complex unprotected peptides in aqueous solvent

NASA Astrophysics Data System (ADS)

Wadzinski, Tyler J.; Steinauer, Angela; Hie, Liana; Pelletier, Guillaume; Schepartz, Alanna; Miller, Scott J.

2018-06-01

Glycosylated natural products and synthetic glycopeptides represent a significant and growing source of biochemical probes and therapeutic agents. However, methods that enable the aqueous glycosylation of endogenous amino acid functionality in peptides without the use of protecting groups are scarce. Here, we report a transformation that facilitates the efficient aqueous O-glycosylation of phenolic functionality in a wide range of small molecules, unprotected tyrosine, and tyrosine residues embedded within a range of complex, fully unprotected peptides. The transformation, which uses glycosyl fluoride donors and is promoted by Ca(OH)2, proceeds rapidly at room temperature in water, with good yields and selective formation of unique anomeric products depending on the stereochemistry of the glycosyl donor. High functional group tolerance is observed, and the phenol glycosylation occurs selectively in the presence of virtually all side chains of the proteinogenic amino acids with the singular exception of Cys. This method offers a highly selective, efficient, and operationally simple approach for the protecting-group-free synthesis of O-aryl glycosides and Tyr-O-glycosylated peptides in water.

Evaluation of sample recovery of malodorous livestock gases from air sampling bags, solid-phase microextraction fibers, Tenax TA sorbent tubes, and sampling canisters.

PubMed

Koziel, Jacek A; Spinhirne, Jarett P; Lloyd, Jenny D; Parker, David B; Wright, Donald W; Kuhrt, Fred W

2005-08-01

Odorous gases associated with livestock operations are complex mixtures of hundreds if not thousands of compounds. Research is needed to know how best to sample and analyze these compounds. The main objective of this research was to compare recoveries of a standard gas mixture of 11 odorous compounds from the Carboxen/PDMS 75-microm solid-phase microextraction fibers, polyvinyl fluoride (PVF; Tedlar), fluorinated ethylene propylene copolymer (FEP; Teflon), foil, and polyethylene terephthalate (PET; Melinex) air sampling bags, sorbent 2,b-diphenylene-oxide polymer resin (Tenax TA) tubes, and standard 6-L Stabilizer sampling canisters after sample storage for 0.5, 24, and 120 (for sorbent tubes only) hrs at room temperature. The standard gas mixture consisted of 7 volatile fatty acids (VFAs) from acetic to hexanoic, and 4 semivolatile organic compounds including p-cresol, indole, 4-ethylphenol, and 2'-aminoacetophenone with concentrations ranging from 5.1 ppb for indole to 1270 ppb for acetic acid. On average, SPME had the highest mean recovery for all 11 gases of 106.2%, and 98.3% for 0.5- and 24-hr sample storage time, respectively. This was followed by the Tenax TA sorbent tubes (94.8% and 88.3%) for 24 and 120 hr, respectively; PET bags (71.7% and 47.2%), FEP bags (75.4% and 39.4%), commercial Tedlar bags (67.6% and 22.7%), in-house-made Tedlar bags (47.3% and 37.4%), foil bags (16.4% and 4.3%), and canisters (4.2% and 0.5%), for 0.5 and 24 hr, respectively. VFAs had higher recoveries than semivolatile organic compounds for all of the bags and canisters. New FEP bags and new foil bags had the lowest and the highest amounts of chemical impurities, respectively. New commercial Tedlar bags had measurable concentrations of N,N-dimethyl acetamide and phenol. Foil bags had measurable concentrations of acetic, propionic, butyric, valeric, and hexanoic acids.

Identifying Complex Mixtures in the Environment with Cheminformatics and Non-targeted High Resolution Mass Spectrometry (SETAC NA Focused Topic Meeting : Risk Assessment of Chemical Mixtures)

EPA Science Inventory

Non-target high resolution mass spectrometry techniques combined with advanced cheminformatics offer huge potential for exploring complex mixtures in our environment – yet also offers plenty of challenges. Peak inventories of several non-target studies from within Europe reveal t...

75 FR 73080 - Science Advisory Board Staff Office; Request for Nominations of Experts for the SAB...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

... are IRIS reference doses (RfDs) for two commercial PCB mixtures: Aroclor 1016 and Aroclor 1254 that... developing a draft assessment of the potential noncancer health hazards of complex PCB mixtures for inclusion... with the goal of establishing an RfD for application to complex PCB mixtures. The EPA's National Center...

Fungal Laccase-Catalyzed Oxidation of Naturally Occurring Phenols for Enhanced Germination and Salt Tolerance of Arabidopsis thaliana: A Green Route for Synthesizing Humic-like Fertilizers.

PubMed

Cha, Joon-Yung; Kim, Tae-Wan; Choi, Jung Hoon; Jang, Kyoung-Soon; Khaleda, Laila; Kim, Woe-Yeon; Jeon, Jong-Rok

2017-02-15

Fungal laccases have been highlighted as a catalytic tool for transforming phenols. Here we demonstrate that fungal laccase-catalyzed oxidations can transform naturally occurring phenols into plant fertilizers with properties very similar to those of commercial humic acids. Treatments of Arabidopsis thaliana with highly cross-linked polyphenolic products obtained from a mixture of catechol and vanillic acid were able to enhance the germination and salt tolerance of this plant. These results revealed that humic-like organic fertilizers can be produced via in vitro enzymatic oxidation reactions. In particular, the root elongation pattern resulting from the laccase products was comparable to that resulting from an auxin-like compound. A detailed structural comparison of the phenol variants and commercial humic acids revealed their similarities and differences. Analyses based on SEM, EFM, ERP, and zeta-potential measurement showed that they both formed globular granules bearing various hydrophilic/polar groups in aqueous and solid conditions. Solid-phase 13 C NMR, FT-IR-ATR, and elemental analyses showed that more nitrogen-based functional and aliphatic groups were present in the commercial humic acids. Significant differences were also identifiable with respect to particle size and specific surface area. High-resolution (15 T) FT-ICR mass spectrometry-based van Krevelen diagrams showed the compositional features of the variants to be a subset of those of the humic acids. Overall, our study unraveled essential structural features of polyaromatics that affect the growth of plants, and also provided novel bottom-up ecofriendly and finely tunable pathways for synthesizing humic-like fertilizers.

Antidiabetic potential: in vitro inhibition effects of some natural phenolic compounds on α-glycosidase and α-amylase enzymes.

PubMed

Taslimi, Parham; Gulçin, İlhami

2017-10-01

α-Glycosidase is a catalytic enzyme and it destroys the complex carbohydrates into simple absorbable sugar units. The natural phenolic compounds were tested for their antidiabetic properties as α-glycosidase and α-amylase inhibitors. The phenolic compounds investigated in this study have been used as antidiabetic common medicines. This paper aimed to consider their capability to inhibit α-amylase and α-glycosidase, two significant enzymes defined in serum glucose adjustment. These examination recorded impressive inhibition profiles with IC 50 values in the range of 137.36-737.23 nM against α-amylase and 29.01-157.96 nM against α-glycosidase. © 2017 Wiley Periodicals, Inc.

Quenching of fluorescence of phenolic compounds and modified humic acids by cadmium ions.

PubMed

Tchaikovskaya, O N; Nechaev, L V; Yudina, N V; Mal'tseva, E V

2016-08-01

The interaction of a number of phenolic compounds, being 'model fragments' of humic acids, with cadmium ions was investigated. The fluorescence quenching method was used to determine the complexation constants of these compounds with cadmium ions. It was established that bonding of phenolic compounds by cadmium ions at рН 7 is weak and reaches a maximum value of 15% for interaction with resorcinol. It was demonstrated that modification of humic acids by the mechanoactivation method increases by three times bonding of cadmium ions, which is caused by strengthening the acid properties of carboxyl and hydroxyl groups at the aromatic ring. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Novel combination of non-aqueous capillary electrophoresis and multivariate curve resolution-alternating least squares to determine phenolic acids in virgin olive oil.

PubMed

Godoy-Caballero, María del Pilar; Culzoni, María Julia; Galeano-Díaz, Teresa; Acedo-Valenzuela, María Isabel

2013-02-06

This paper presents the development of a non-aqueous capillary electrophoresis method coupled to UV detection combined with multivariate curve resolution-alternating least-squares (MCR-ALS) to carry out the resolution and quantitation of a mixture of six phenolic acids in virgin olive oil samples. p-Coumaric, caffeic, ferulic, 3,4-dihydroxyphenylacetic, vanillic and 4-hydroxyphenilacetic acids have been the analytes under study. All of them present different absorption spectra and overlapped time profiles with the olive oil matrix interferences and between them. The modeling strategy involves the building of a single MCR-ALS model composed of matrices augmented in the temporal mode, namely spectra remain invariant while time profiles may change from sample to sample. So MCR-ALS was used to cope with the coeluting interferences, on accounting the second order advantage inherent to this algorithm which, in addition, is able to handle data sets deviating from trilinearity, like the data herein analyzed. The method was firstly applied to resolve standard mixtures of the analytes randomly prepared in 1-propanol and, secondly, in real virgin olive oil samples, getting recovery values near to 100% in all cases. The importance and novelty of this methodology relies on the combination of non-aqueous capillary electrophoresis second-order data and MCR-ALS algorithm which allows performing the resolution of these compounds simplifying the previous sample pretreatment stages. Copyright © 2012 Elsevier B.V. All rights reserved.

Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols.

PubMed

Abdallah, Hossam M; El-Bassossy, Hany; Mohamed, Gamal A; El-Halawany, Ali M; Alshali, Khalid Z; Banjar, Zainy M

2016-02-22

Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3',4,5',6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2-4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1-4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

Dereplication of plant phenolics using a mass-spectrometry database independent method.

PubMed

Borges, Ricardo M; Taujale, Rahil; de Souza, Juliana Santana; de Andrade Bezerra, Thaís; Silva, Eder Lana E; Herzog, Ronny; Ponce, Francesca V; Wolfender, Jean-Luc; Edison, Arthur S

2018-05-29

Dereplication, an approach to sidestep the efforts involved in the isolation of known compounds, is generally accepted as being the first stage of novel discoveries in natural product research. It is based on metabolite profiling analysis of complex natural extracts. To present the application of LipidXplorer for automatic targeted dereplication of phenolics in plant crude extracts based on direct infusion high-resolution tandem mass spectrometry data. LipidXplorer uses a user-defined molecular fragmentation query language (MFQL) to search for specific characteristic fragmentation patterns in large data sets and highlight the corresponding metabolites. To this end, MFQL files were written to dereplicate common phenolics occurring in plant extracts. Complementary MFQL files were used for validation purposes. New MFQL files with molecular formula restrictions for common classes of phenolic natural products were generated for the metabolite profiling of different representative crude plant extracts. This method was evaluated against an open-source software for mass-spectrometry data processing (MZMine®) and against manual annotation based on published data. The targeted LipidXplorer method implemented using common phenolic fragmentation patterns, was found to be able to annotate more phenolics than MZMine® that is based on automated queries on the available databases. Additionally, screening for ascarosides, natural products with unrelated structures to plant phenolics collected from the nematode Caenorhabditis elegans, demonstrated the specificity of this method by cross-testing both groups of chemicals in both plants and nematodes. Copyright © 2018 John Wiley & Sons, Ltd.

Excretion of Avenanthramides, Phenolic Acids and their Major Metabolites Following Intake of Oat Bran

PubMed Central

Schär, Manuel Y.; Corona, Giulia; Soycan, Gulten; Dine, Clemence; Kristek, Angelika; Alsharif, Sarah N. S.; Behrends, Volker; Lovegrove, Alison; Shewry, Peter R.

2017-01-01

Scope Wholegrain has been associated with reduced chronic disease mortality, with oat intake particularly notable for lowering blood cholesterol and glycemia. To better understand the complex nutrient profile of oats, we studied urinary excretion of phenolic acids and avenanthramides after ingestion of oat bran in humans. Methods and results After a 2‐d (poly)phenol‐low diet, seven healthy men provided urine 12 h before and 48 h after consuming 60 g oat bran (7.8 μmol avenanthramides, 139.2 μmol phenolic acids) or a phenolic‐low (traces of phenolics) control in a crossover design. Analysis by ultra‐high performance liquid chromatography (UPLC)–MS/MS showed that oat bran intake resulted in an elevation in urinary excretion of 30 phenolics relative to the control, suggesting that they are oat bran‐derived. Mean excretion levels were elevated between 0–2 and 4–8 h, following oat bran intake, and amounted to a total of 33.7 ± 7.3 μmol total excretion (mean recovery: 22.9 ± 5.0%), relative to control. The predominant metabolites included: vanillic acid, 4‐ and 3‐hydroxyhippuric acids, and sulfate‐conjugates of benzoic and ferulic acids, which accounted collectively for two thirds of total excretion. Conclusion Oat bran phenolics follow a relatively rapid urinary excretion, with 30 metabolites excreted within 8 h of intake. These levels of excretion suggest that bound phenolics are, in part, rapidly released by the microbiota. PMID:29024323

Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities

NASA Astrophysics Data System (ADS)

Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

2014-03-01

Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ≫ 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

Stable divalent germanium, tin and lead amino(ether)-phenolate monomeric complexes: structural features, inclusion heterobimetallic complexes, and ROP catalysis.

PubMed

Wang, Lingfang; Roşca, Sorin-Claudiu; Poirier, Valentin; Sinbandhit, Sourisak; Dorcet, Vincent; Roisnel, Thierry; Carpentier, Jean-François; Sarazin, Yann

2014-03-21

Stable germanium(II) and lead(II) amido complexes {LO(i)}M(N(SiMe3)2) (M = Ge(II), Pb(II)) bearing amino(ether)phenolate ligands are readily available using the proteo-ligands {LO(i)}H of general formula 2-CH2NR2-4,6-tBu2-C6H2OH (i = 1, NR2 = N((CH2)2OCH3)2; i = 2, NR2 = NEt2; i = 3, NR2 = aza-15-crown-5) and M(N(SiMe3)2)2 precursors. The molecular structures of these germylenes and plumbylenes, as well as those of {LO(3)}GeCl, {LO(3)}SnCl and of the congeneric {LO(4)}Sn(II)(N(SiMe3)2) where NR2 = aza-12-crown-4, have been determined crystallographically. All complexes are monomeric, with 3-coordinate metal centres. The phenolate systematically acts as a N^O(phenolate) bidentate ligand, with no interactions between the metal and the O(side-arm) atoms in these cases (for {LO(1)}(-), {LO(3)}(-) and {LO(4)}(-)) where they could potentially arise. For each family, the lone pair of electrons essentially features ns(2) character, and there is little, if any, hybridization of the valence orbitals. Heterobimetallic complexes {LO(3)}M(N(SiMe3)2)·LiOTf, where the Li(+) cation sits inside the tethered crown-ether, were prepared by reaction of {LO(3)}M(N(SiMe3)2) and LiOTf (M = Ge(II), Sn(II)). The inclusion of Li(+) (featuring a close contact with the triflate anion) in the macrocycle bears no influence on the coordination sphere of the divalent tetrel element. In association with iPrOH, the amido germylenes, stannylenes and plumbylenes catalyse the controlled polymerisation of L- and racemic lactide. The activity increases linearly according to Ge(II) ≪ Sn(II) ≪ Pb(II). The simple germylenes generate very sluggish catalysts, but the activity is significantly boosted if the heterobimetallic complex {LO(3)}Ge(N(SiMe3)2)·LiOTf is used instead. On the other hand, with 10-25 equiv. of iPrOH, the plumbylenes afford highly active binary catalysts, converting 1000 or 5000 equiv. of monomer at 60 °C within 3 or 45 min, respectively, in a controlled fashion.

Synthesis of m-Alkylphenols via a Ruthenium-Catalyzed C-H Bond Functionalization of Phenol Derivatives.

PubMed

Li, Gang; Gao, Panpan; Lv, Xulu; Qu, Chen; Yan, Qingkai; Wang, Ya; Yang, Suling; Wang, Junjie

2017-05-19

The first example of the synthesis of m-alkylphenols via a ruthenium-catalyzed C Ar -H bond functionalization of phenol derivatives with sec/tert-alkyl bromides is reported. Mechanistic studies indicated that the m-C Ar -H bond alkylation may involve a radical process and that a six-membered ruthenacycle complex was the active catalyst. Moreover, this approach can provide an expedited strategy for the atom-/step-economical synthesis of many noteworthy pharmaceuticals and other functional molecules.

STRATEGIES TO IDENTIFY BIOACTIVE SUBSTANCES IN COMPLEX AIR POLLUTANT MIXTURES

EPA Science Inventory

Both indoor and outdoor air contains a very complex mixture of gas and particulate matter (PM) pollutants. The assessment of the role of each pollutant in the complex atmosphere in the induction of an associated health effect or a response can be difficult due to many factors, i...

Complexation Effect on Redox Potential of Iron(III)-Iron(II) Couple: A Simple Potentiometric Experiment

ERIC Educational Resources Information Center

Rizvi, Masood Ahmad; Syed, Raashid Maqsood; Khan, Badruddin

2011-01-01

A titration curve with multiple inflection points results when a mixture of two or more reducing agents with sufficiently different reduction potentials are titrated. In this experiment iron(II) complexes are combined into a mixture of reducing agents and are oxidized to the corresponding iron(III) complexes. As all of the complexes involve the…

Modeling the chemistry of complex petroleum mixtures.

PubMed Central

Quann, R J

1998-01-01

Determining the complete molecular composition of petroleum and its refined products is not feasible with current analytical techniques because of the astronomical number of molecular components. Modeling the composition and behavior of such complex mixtures in refinery processes has accordingly evolved along a simplifying concept called lumping. Lumping reduces the complexity of the problem to a manageable form by grouping the entire set of molecular components into a handful of lumps. This traditional approach does not have a molecular basis and therefore excludes important aspects of process chemistry and molecular property fundamentals from the model's formulation. A new approach called structure-oriented lumping has been developed to model the composition and chemistry of complex mixtures at a molecular level. The central concept is to represent an individual molecular or a set of closely related isomers as a mathematical construct of certain specific and repeating structural groups. A complex mixture such as petroleum can then be represented as thousands of distinct molecular components, each having a mathematical identity. This enables the automated construction of large complex reaction networks with tens of thousands of specific reactions for simulating the chemistry of complex mixtures. Further, the method provides a convenient framework for incorporating molecular physical property correlations, existing group contribution methods, molecular thermodynamic properties, and the structure--activity relationships of chemical kinetics in the development of models. PMID:9860903

Novel approaches mediated by tailor-made green solvents for the extraction of phenolic compounds from agro-food industrial by-products.

PubMed

Fernández, María de Los Ángeles; Espino, Magdalena; Gomez, Federico J V; Silva, María Fernanda

2018-01-15

An environmentally friendly method for the phenolic compound extraction from agro-food industrial by-products was developed in order to contribute with their sustainable valorization. A Natural Deep Eutectic Solvent was chemometrically-designed for the first time and compared with traditional solvents in terms of analyte stabilization. The combination of lactic acid, glucose and 15% water (LGH-15) was selected as optimal. A high-efficiency ultrasound-assisted extraction mediated by LGH-15 prior to HPLC-DAD allows the determination of 14 phenols in onion, olive, tomato and pear industrial by-products. NADES synthesis as well as the extraction procedures were optimized by Response Surface Methodology. Thus, phenolic determination in these complex samples was achieved by a simple, non-expensive, eco-friendly and robust system. The application to different matrices demonstrated the versatility of the proposed method. NADES opens interesting perspectives for their potential use as vehicles of bioactive compounds as food additives or pharmaceuticals. Copyright © 2017 Elsevier Ltd. All rights reserved.

The integration of cyanide hydratase and tyrosinase catalysts enables effective degradation of cyanide and phenol in coking wastewaters.

PubMed

Martínková, Ludmila; Chmátal, Martin

2016-10-01

The aim of this study was to design an effective method for the bioremediation of coking wastewaters, specifically for the concurrent elimination of their highly toxic components - cyanide and phenols. Almost full degradation of free cyanide (0.32-20 mM; 8.3-520 mg L(-1)) in the model and the real coking wastewaters was achieved by using a recombinant cyanide hydratase in the first step. The removal of cyanide, a strong inhibitor of tyrosinase, enabled an effective degradation of phenols by this enzyme in the second step. Phenol (16.5 mM, 1,552 mg L(-1)) was completely removed from a real coking wastewater within 20 h and cresols (5.0 mM, 540 mg L(-1)) were removed by 66% under the same conditions. The integration of cyanide hydratase and tyrosinase open up new possibilities for the bioremediation of wastewaters with complex pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vibrational dynamics of hydrogen-bonded complexes in solutions studied with ultrafast infrared pump-probe spectroscopy.

PubMed

Banno, Motohiro; Ohta, Kaoru; Yamaguchi, Sayuri; Hirai, Satori; Tominaga, Keisuke

2009-09-15

In aqueous solution, the basis of all living processes, hydrogen bonding exerts a powerful effect on chemical reactivity. The vibrational energy relaxation (VER) process in hydrogen-bonded complexes in solution is sensitive to the microscopic environment around the oscillator and to the geometrical configuration of the hydrogen-bonded complexes. In this Account, we describe the use of time-resolved infrared (IR) pump-probe spectroscopy to study the vibrational dynamics of (i) the carbonyl CO stretching modes in protic solvents and (ii) the OH stretching modes of phenol and carboxylic acid. In these cases, the carbonyl group acts as a hydrogen-bond acceptor, whereas the hydroxyl group acts as a hydrogen-bond donor. These vibrational modes have different properties depending on their respective chemical bonds, suggesting that hydrogen bonding may have different mechanisms and effects on the VER of the CO and OH modes than previously understood. The IR pump-probe signals of the CO stretching mode of 9-fluorenone and methyl acetate in alcohol, as well as that of acetic acid in water, include several components with different time constants. Quantum chemical calculations indicate that the dynamical components are the result of various hydrogen-bonded complexes that form between solute and solvent molecules. The acceleration of the VER is due to the increasing vibrational density of states caused by the formation of hydrogen bonds. The vibrational dynamics of the OH stretching mode in hydrogen-bonded complexes were studied in several systems. For phenol-base complexes, the decay time constant of the pump-probe signal decreases as the band peak of the IR absorption spectrum shifts to lower wavenumbers (the result of changing the proton acceptor). For phenol oligomers, the decay time constant of the pump-probe signal decreases as the probe wavenumber decreases. These observations show that the VER time strongly correlates with the strength of hydrogen bonding. This acceleration may be due to increased coupling between the OH stretching mode and the accepting mode of the VER, because the low-frequency shift caused by hydrogen bond formation is very large. Unlike phenol oligomers, however, the pump-probe signals of phenol-base complexes did not exhibit probe frequency dependence. For these complexes, rapid interconversion between different conformations causes rapid fluctuations in the vibrational frequency of the OH stretching modes, and these fluctuations level the VER times of different conformations. For the benzoic acid dimer, a quantum beat at a frequency of around 100 cm(-1) is superimposed on the pump-probe signal. This result indicates the presence of strong anharmonic coupling between the intramolecular OH stretching and the intermolecular stretching modes. From a two-dimensional plot of the OH stretching wavenumber and the low-frequency wavenumber, the wavenumber of the low-frequency mode is found to increase monotonically as the probe wavenumber is shifted toward lower wavenumbers. Our results represent a quantitative determination of the acceleration of VER by the formation of hydrogen bonds. Our studies merit further evaluation and raise fundamental questions about the current theory of vibrational dynamics in the condensed phase.

Oil composition and characterisation of phenolic compounds of Opuntia ficus-indica seeds.

PubMed

Chougui, Nadia; Tamendjari, Abderezak; Hamidj, Wahiba; Hallal, Salima; Barras, Alexandre; Richard, Tristan; Larbat, Romain

2013-08-15

The seed composition of four varieties of Opuntia ficus-indica growing in Algeria was investigated. Seeds ground into a fine powder were first, subjected to oil extraction and fatty acids analysis. The phenolic compounds were then extracted from the defatted powder of seeds in order to be quantified and characterised by liquid chromatography coupled to mass spectrometry (LC-MS(n)) and to nuclear magnetic resonance (LC-NMR) approaches. In addition, an evaluation of the antioxidant activity of the phenolic extracts was investigated. Gas chromatography analysis of the seed oil showed high percentages of linoleic acid in the four varieties ranging from 58% to 63%. The phenolic profile of the Opuntia ficus-indica seeds displayed a high complexity, with more than 20 compounds detected at 330 nm after the LC separation. Among them, three isomers of feruloyl-sucrose were firmly identified and another was strongly supposed to be a sinapoyl-diglycoside. High correlations were found between phenolic content in the defatted seed extracts and their antioxidant activity. The data indicate that the defatted cactus seed wastes still contain various components that constitute a source for natural foods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Screening plant derived dietary phenolic compounds for bioactivity related to cardiovascular disease.

PubMed

Croft, Kevin D; Yamashita, Yoko; O'Donoghue, Helen; Shirasaya, Daishi; Ward, Natalie C; Ashida, Hitoshi

2018-04-01

The potential health benefits of phenolic acids found in food and beverages has been suggested from a number of large population studies. However, the mechanism of how these compounds may exert biological effects is less well established. It is also now recognised that many complex polyphenols in the diet are metabolised to simple phenolic acids which can be taken up in the circulation. In this paper a number of selected phenolic compounds have been tested for their bioactivity in two cell culture models. The expression and activity of endothelial nitric oxide synthase (eNOS) in human aortic endothelial cells and the uptake of glucose in muscle cells. Our data indicate that while none of the compounds tested had a significant effect on eNOS expression or activation in endothelial cells, several of the compounds increased glucose uptake in muscle cells. These compounds also enhanced the translocation of the glucose transporter GLUT4 to the plasma membrane, which may explain the observed increase in cellular glucose uptake. These results indicate that simple cell culture models may be useful to help understand the bioactivity of phenolic compounds in relation to cardiovascular protection. Copyright © 2017 Elsevier B.V. All rights reserved.

Unimolecular thermal decomposition of phenol and d5-phenol: Direct observation of cyclopentadiene formation via cyclohexadienone

NASA Astrophysics Data System (ADS)

Scheer, Adam M.; Mukarakate, Calvin; Robichaud, David J.; Nimlos, Mark R.; Carstensen, Hans-Heinrich; Barney Ellison, G.

2012-01-01

The pyrolyses of phenol and d5-phenol (C6H5OH and C6D5OH) have been studied using a high temperature, microtubular (μtubular) SiC reactor. Product detection is via both photon ionization (10.487 eV) time-of-flight mass spectrometry and matrix isolation infrared spectroscopy. Gas exiting the heated reactor (375 K-1575 K) is subject to a free expansion after a residence time in the μtubular reactor of approximately 50-100 μs. The expansion from the reactor into vacuum rapidly cools the gas mixture and allows the detection of radicals and other highly reactive intermediates. We find that the initial decomposition steps at the onset of phenol pyrolysis are enol/keto tautomerization to form cyclohexadienone followed by decarbonylation to produce cyclopentadiene; C6H5OH → c-C6H6 = O → c-C5H6 + CO. The cyclopentadiene loses a H atom to generate the cyclopentadienyl radical which further decomposes to acetylene and propargyl radical; c-C5H6 → c-C5H5 + H → HC≡CH + HCCCH2. At higher temperatures, hydrogen loss from the PhO-H group to form phenoxy radical followed by CO ejection to generate the cyclopentadienyl radical likely contributes to the product distribution; C6H5O-H → C6H5O + H → c-C5H5 + CO. The direct decarbonylation reaction remains an important channel in the thermal decomposition mechanisms of the dihydroxybenzenes. Both catechol (o-HO-C6H4-OH) and hydroquinone (p-HO-C6H4-OH) are shown to undergo decarbonylation at the onset of pyrolysis to form hydroxycyclopentadiene. In the case of catechol, we observe that water loss is also an important decomposition channel at the onset of pyrolysis.

Enhanced phenol-photodegradation by particulate semiconductor mixtures: interparticle electron-jump.

PubMed

Karunakaran, C; Dhanalakshmi, R; Gomathisankar, P; Manikandan, G

2010-04-15

Degradation of phenol on suspended TiO(2), ZnO, CdO, Fe(2)O(3), CuO, ZnS and Nb(2)O(5) particles under UV-A light exhibit identical photokinetic behavior; follow first-order kinetics, display linear dependence on the photon flux and slowdown with increase of pH. All the semiconductors show sustainable photocatalytic activity. Dissolved O(2) is essential for the photodegradation and oxidizing agents like H(2)O(2), Na(2)BO(3), K(2)S(2)O(8), KBrO(3), KIO(3) and KIO(4), reducing agents such as NaNO(2) and Na(2)SO(3) and sacrificial electron donors like hydroquinone, diphenyl amine and trimethyl amine enhance the degradation. However, the photocatalysis is insensitive to pre-sonication. Two particulate semiconductors present together, under suspension and at continuous motion, enhance the photocatalytic degradation up to about four-fold revealing interparticle electron-jump. 2009 Elsevier B.V. All rights reserved.

Synthesis characterization and catalytic action of hexagonal gold nanoparticles using essential oils extracted from Anacardium occidentale

NASA Astrophysics Data System (ADS)

Sheny, D. S.; Mathew, Joseph; Philip, Daizy

2012-11-01

A new phytochemical method for the synthesis of gold nanoparticles is reported. The essential oils extracted from the fresh leaves of Anacardium occidentale are used for the reduction of auric acid to Au nanoparticles (NPs). The formation and morphology of synthesized NPs are investigated with the help of UV-visible, TEM and FTIR spectroscopy. The NPs synthesized at room temperature are mono-dispersed and hexagonal in shape with an average size of 36 nm while those prepared at higher temperature are composed of a mixture of anisotropic particles. The UV-visible absorption spectra of these anisotropic NPs show asymmetry in the longer wavelength side. The quantity of oil is an important criterion modulating the shape of NPs. Possible biochemical mechanism leading to the formation of NPs is studied using FTIR spectroscopy. The potential of synthesized Au NPs as catalyst is explored for the hydrogenation of p-nitro phenol to p-amino phenol at room temperature.

Remediation of the effect of adding cyanides on an algal/bacterial treatment of a mixture of organic pollutants in a continuous photobioreactor.

PubMed

Essam, Tamer; ElRakaiby, Marwa; Agha, Azza

2014-09-01

The effect of inorganic pollutants on the treatment of organic pollutants using algal/bacterial microcosm was investigated in a continuous photobioreactor. The microcosm was composed of Chlorella vulgaris MM1 and Pseudomonas MT1 and was able to efficiently treat artificial waste-water contaminated with 6.4 salicylate and 2.2 mM phenol at a hydraulic retention time of 4 days. No negative effect was recorded when the waste-water was supplemented with 1.6 mM thiocyanate; however, the treatment efficiency severely deteriorated when the system was challenged with 0.74 mM cyanide. Addition of 2 g NaHCO3 l(-1) did not improve the efficiency of the treatment. Toxicity of the pollutants to the alga was cyanide > thiocyanate > phenol > salicylate. The high toxicity of the waste-water was eliminated either by a 25-fold dilution or by photocatalytic pre-treatment which allowed the subsequent efficient biological treatment.

Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials.

PubMed

Ballesteros, Lina F; Ramirez, Monica J; Orrego, Carlos E; Teixeira, José A; Mussatto, Solange I

2017-12-15

Freeze-drying and spray-drying techniques were evaluated for encapsulation of phenolic compounds (PC) extracted from spent coffee grounds. Additionally, the use of maltodextrin, gum arabic and a mixture of these components (ratio 1:1) as wall material to retain the PC and preserve their antioxidant activity was also assessed. The contents of PC and flavonoids (FLA), as well as the antioxidant activity of the encapsulated samples were determined in order to verify the efficiency of each studied condition. Additional analyses for characterization of the samples were also performed. Both the technique and the coating material greatly influenced the encapsulation of antioxidant PC. The best results were achieved when PC were encapsulated by freeze-drying using maltodextrin as wall material. Under these conditions, the amount of PC and FLA retained in the encapsulated sample corresponded to 62% and 73%, respectively, and 73-86% of the antioxidant activity present in the original extract was preserved. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a beverage benchtop prototype based on sweet potato peels: optimization of antioxidant activity by a mixture design.

PubMed

Anastácio, Ana; Carvalho, Isabel Saraiva de

2015-08-01

A beverage benchtop prototype related to oxidative stress protection was developed based on sweet potato peels phenolics. Formula components were sweet potato peel (Ipomoeas batatas L.) aqueous extract (SPPE), sweet potato leaves water extract (SPLE) and honey solution (HonS). According to linear squares regression (LSR) models, SPLE presented higher additive effect on total phenolic content (TPC), FRAP and DPPH than the other components. All antagonist interactions were not significant. The optimum formula obtained by artificial neural networks (ANN) analysis was 50.0% of SPPE, 21.5% of SPLE and 28.5% of HonS. Predicted responses of TPC, FRAP, DPPH and soluble solids were 309 mg GAE/L, 476 mg TE/L, 1098 mg TE/L and 12.3 °Brix, respectively. Optimization with LSR models was similar to ANN. Beverage prototype results positioned next to commercial vegetable and fruit beverages, thus it has an interesting potential to the market of health and wellness.

Synthesis of Coral-Like Tantalum Oxide Films via Anodization in Mixed Organic-Inorganic Electrolytes

PubMed Central

Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

2013-01-01

We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two–electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%. PMID:23799106

Measurements of the effects of wine maceration with oak chips using an electronic tongue.

PubMed

Rudnitskaya, Alisa; Schmidtke, Leigh M; Reis, Ana; Domingues, M Rosario M; Delgadillo, Ivonne; Debus, Bruno; Kirsanov, Dmitry; Legin, Andrey

2017-08-15

The use of oak products as a cheaper alternative to expensive wood barrels was recently permitted in Europe, which led to a continuous increase in the use of oak chips and staves in winemaking. The feasibility of the potentiometric electronic tongue as a tool for monitoring the effects of wine maceration with oak chips was evaluated. Four types of commercially available oak chips subjected to different thermal treatments and washing procedures and their mixture were studied. Ethanolic extracts of the chips were analysed using electrospray mass spectrometry and 28 phenolic and furanic compounds were identified. The electronic tongue comprising 22 potentiometric chemical sensors could distinguish artificial wine solutions and Cabernet Sauvignon wine macerated with different types of oak chips, quantify total and non-flavonoid phenolic content, as well as the concentrations of added oak chips. Using measurements at two pH levels, 3.2 and 6.5, improved the accuracy of quantification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Label-free potentiometric biosensor based on solid-contact for determination of total phenols in honey and propolis.

PubMed

Draghi, Patrícia Ferrante; Fernandes, Julio Cesar Bastos

2017-03-01

We developed a label-free potentiometric biosensor using tyrosinase extracted from Musa acuminata and immobilized by covalent bond on a surface of a solid-contact transducer. The transducer was manufactured containing two layers. The first layer contained a blend of poly(vinyl) chloride carboxylated (PVC-COOH), graphite and potassium permanganate. On this layer, we deposited a second layer containing just a mixture of poly(vinyl chloride) carboxylated and graphite. On the last layer of the transducer, we immobilized the tyrosinase enzyme by reaction with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride. The solid-contact potentiometric biosensor presented at low detection limit of 7.3×10 -7 M and a linear range to catechol concentration between 9.3×10 -7 M and 8.3×10 -2 M. This biosensor was applied to determine the amount of total phenols in different samples of honey and propolis. The results agreed with the Folin-Ciocalteu method. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of Water on the Thermo-Mechanical Behavior of Carbon Cloth Phenolic

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.; Stokes, Eric; Baker, Eric H.

2011-01-01

The results of thermo-mechanical experiments, which were conducted previously by one of the authors, are reviewed. The strain in the direction normal to the fabric plane was measured as a function of temperature for a variety of initial moisture contents and heating rates. In this paper, the general features of the thermo-mechanical response are discussed and the effect of heating rate and initial moisture content are highlighted. The mechanical interaction between the phenolic polymer and water trapped within its free volumes as the polymer is heated to high temperatures is discussed. An equation for the internal stresses which are generated within the polymer due to trapped water is obtained from the total stress expression for a binary mixture of polymer and water. Numerical solutions for moisture diffusion in the thermo-mechanical experiments were performed and the results of these solutions are presented. The results of the moisture diffusion solutions help to explain the effects of heating rate and moisture content on the strain behavior normal to the fabric plane.

Synthesis characterization and catalytic action of hexagonal gold nanoparticles using essential oils extracted from Anacardium occidentale.

PubMed

Sheny, D S; Mathew, Joseph; Philip, Daizy

2012-11-01

A new phytochemical method for the synthesis of gold nanoparticles is reported. The essential oils extracted from the fresh leaves of Anacardium occidentale are used for the reduction of auric acid to Au nanoparticles (NPs). The formation and morphology of synthesized NPs are investigated with the help of UV-visible, TEM and FTIR spectroscopy. The NPs synthesized at room temperature are mono-dispersed and hexagonal in shape with an average size of 36 nm while those prepared at higher temperature are composed of a mixture of anisotropic particles. The UV-visible absorption spectra of these anisotropic NPs show asymmetry in the longer wavelength side. The quantity of oil is an important criterion modulating the shape of NPs. Possible biochemical mechanism leading to the formation of NPs is studied using FTIR spectroscopy. The potential of synthesized Au NPs as catalyst is explored for the hydrogenation of p-nitro phenol to p-amino phenol at room temperature. Copyright © 2012 Elsevier B.V. All rights reserved.

Bacterial metabolism of aromatic compounds and a complex hazardous waste under anaerobic conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Connor, O.A.

1992-01-01

The biological fate of organic chemicals in the environment depends upon a variety of physical/chemical factors. In the absence of molecular oxygen, the importance of terminal electron acceptors has been often overlooked. Since anaerobic microbial consortia are dependent upon the availability of particular electron acceptors, these conditions can play an important role in influencing the fate of environmental pollutants. In this research, different electron acceptors were evaluated for their effects on the biodegradation of environmental toxicants. Two anaerobic bioassays, the Biochemical Methane Potential (BMP) and the Anaerobic Toxicity Assay (ATA), were used to evaluate a series of phthalic acid estersmore » (PAEs), substituted phenols and a landfill leachate, for their methanogenic biodegradability and toxicity. Many of the PAEs and phenols could be stoichiometrically mineralized. In addition, the landfill leachate was found to be inhibitory at concentrations greater than 10%, and partially mineralized in approximately 50 weeks. Based upon these assays, 6 different functional groups and their isomers were evaluated for their effect on the biodegradability and toxicity of phenol under methanogenic and denitrifying conditions. These results indicated that nitro- and chloro-substituted phenols were persistent under denitrifying conditions. Under methanogenic conditions, these compounds were metabolized to a more reduced intermediate with less toxicity. Conversely, amino-substituted phenols were not readily mineralized under methanogenic conditions, but were metabolized after minimal lag under denitrifying conditions. From active denitrifying phenol degrading cultures, a pure culture was obtained which could grow on phenol and on a variety of other alkyl-substituted aromatic compounds. Additional studies have tentatively identified several alicyclic metabolites including cyclohexanol, 2-cyclohexene-1-ol, cyclohexanone and 2-cyclohexene-1-one from phenol catabolism.« less

Enhanced photoluminescence from single nitrogen-vacancy defects in nanodiamonds coated with phenol-ionic complexes

NASA Astrophysics Data System (ADS)

Bray, Kerem; Previdi, Rodolfo; Gibson, Brant C.; Shimoni, Olga; Aharonovich, Igor

2015-03-01

Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications.Fluorescent nanodiamonds are attracting major attention in the field of bio-sensing and bio-labeling. In this work we demonstrate a robust approach to achieve an encapsulation of individual nanodiamonds with phenol-ionic complexes that enhance the photoluminescence from single nitrogen vacancy (NV) centers. We show that single NV centres in the coated nanodiamonds also exhibit shorter lifetimes, opening another channel for high resolution sensing. We propose that the nanodiamond encapsulation reduces the non-radiative decay pathways of the NV color centers. Our results provide a versatile and assessable way to enhance photoluminescence from nanodiamond defects that can be used in a variety of sensing and imaging applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07510b

Electrochemical and spectroscopic effects of mixed substituents in bis(phenolate)–copper(II) galactose oxidase model complexes

PubMed Central

Pratt, Russell C.; Lyons, Christopher T.; Wasinger, Erik C.; Stack, T. Daniel. P.

2012-01-01

Non-symmetric substitution of salen (1R1,R2) and reduced salen (2R1,R2) CuII-phenoxyl complexes with a combination of -tBu, -SiPr, and -OMe substituents leads to dramatic differences in their redox and spectroscopic properties, providing insight into the influence of the cysteine-modified tyrosine cofactor in the enzyme galactose oxidase (GO). Using a modified Marcus-Hush analysis, the oxidized copper complexes are characterized as Class II mixed-valent due to the electronic differentiation between the two substituted phenolates. Sulfur K-edge X-ray absorption spectroscopy (XAS) assesses the degree of radical delocalization onto the single sulfur atom of non-symmetric [1tBu,SMe]+ at 7%, consistent with other spectroscopic and electrochemical results that suggest preferential oxidation of the -SMe bearing phenolate. Estimates of the thermodynamic free-energy difference between the two localized states (ΔG∘) and reorganizational energies (λR1R2) of [1R1,R2]+ and [2R1,R2]+ leads to accurate predictions of the spectroscopically observed IVCT transition energies. Application of the modified Marcus-Hush analysis to GO using parameters determined for [2R1,R2]+ predicts a νmax of ~ 13600 cm−1, well within the energy range of the broad Vis-NIR band displayed by the enzyme. PMID:22471355

MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

EPA Science Inventory

Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

Supercritical separation process for complex organic mixtures

DOEpatents

Chum, Helena L.; Filardo, Giuseppe

1990-01-01

A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

Ultra-high performance supercritical fluid chromatography of lignin-derived phenols from alkaline cupric oxide oxidation.

PubMed

Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta; Turner, Charlotta

2016-08-01

Traditional chromatographic methods for the analysis of lignin-derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra-high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin-derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5-2.5 μM, a limit of quantification of 2.5-5.0 μM, and a dynamic range of 5.0-2.0 mM (R(2) > 0.997). The new ultra-high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin-derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin-derived phenols in complex environmental samples. © 2016 The Authors, Journal of Separation Science Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phenolic profiling of Portuguese propolis by LC-MS spectrometry: uncommon propolis rich in flavonoid glycosides.

PubMed

Falcão, Soraia I; Vale, Nuno; Gomes, Paula; Domingues, Maria R M; Freire, Cristina; Cardoso, Susana M; Vilas-Boas, Miguel

2013-01-01

Propolis is a chemically complex resinous substance collected by honeybees (Apis mellifera) from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. Its chemical composition depends strongly on the plant sources available around the beehive, which have a direct impact in the quality and bioactivity of the propolis. Being as Portugal is a country of botanical diversity, the phenolic characterisation of propolis from the different regions is a priority. Extensive characterisation of the phenolic composition of Portuguese propolis from different continental regions and islands. Forty propolis ethanolic extracts were analysed extensively by liquid chromatography with diode-array detection coupled to electrospray ionisation tandem mass spectrometry (LC-DAD-ESI-MS(n) ). Seventy-six polyphenols were detected in the samples and two groups of propolis were established: the common temperate propolis, which contained the typical poplar phenolic compounds such as flavonoids and their methylated/esterified forms, phenylpropanoid acids and their esters, and an uncommon propolis type with an unusual composition in quercetin and kaempferol glycosides - some of them never described in propolis. The method allowed the establishment of the phenolic profile of Portuguese propolis from different geographical locations, and the possibility to use some phenolic compounds, such as kaempferol-dimethylether, as geographical markers. Data suggest that other botanical species in addition to poplar trees can be important sources of resins for Portuguese propolis. Copyright © 2012 John Wiley & Sons, Ltd.

Comparative Study of the Use of Trichloroacetic Acid and Phenolic Acid in the Treatment of Atrophic-Type Acne Scars.

PubMed

Dalpizzol, Mariana; Weber, Magda B; Mattiazzi, Anna Paula F; Manzoni, Ana Paula D

2016-03-01

Many therapies involving varying degrees of complexity have been used to treat acne scars, but none is considered the gold standard treatment. A comparative evaluation of 88% phenol and 90% trichloroacetic acid (TCA) applied using the chemical reconstruction of skin scars (CROSS) technique. A nonrandomized, single-blinded self-controlled clinical trial was conducted among patients with ice pick-type and boxcar-type atrophic acne scars. Using 88% phenol on the left hemiface and 90% TCA on the right hemiface was adopted as the standard practice of the CROSS technique. The dermatological quality of life index (DLQI) questionnaire, acne scar grading scale Échelle d´Evaluation Clinique des Cicatrices d'Acne (ECCA), and evaluation of improvement were performed pretreatment and post-treatment. Regarding ECCA, significant differences were found in pretreatment and post-treatment (p < .001). Regarding tolerance to pain, it was found that the discomfort felt with 90% TCA was significantly less than that felt with 88% phenol (p = .020). Regarding the quality of life measured with the DLQI, the results showed that the mean score in post-treatment assessment was significantly lower than that in the pretreatment assessment (p < .05). Hypochromia and enlargement scar were only seen after the use of 90% TCA. This study confirmed the efficacy of both TCA and phenol for treating such scars, with less severe complications from the use of phenol.

Intestinal Permeability and Cellular Antioxidant Activity of Phenolic Compounds from Mango (Mangifera indica cv. Ataulfo) Peels

PubMed Central

Pacheco-Ordaz, Ramón; González-Aguilar, Gustavo A.

2018-01-01

Mango (Mangifera indica cv. Ataulfo) peel contains bound phenolics that may be released by alkaline or acid hydrolysis and may be converted into less complex molecules. Free phenolics from mango cv. Ataulfo peel were obtained using a methanolic extraction, and their cellular antioxidant activity (CAA) and permeability were compared to those obtained for bound phenolics released by alkaline or acid hydrolysis. Gallic acid was found as a simple phenolic acid after alkaline hydrolysis along with mangiferin isomers and quercetin as aglycone and glycosides. Only gallic acid, ethyl gallate, mangiferin, and quercetin were identified in the acid fraction. The acid and alkaline fractions showed the highest CAA (60.5% and 51.5%) when tested at 125 µg/mL. The value of the apparent permeability coefficient (Papp) across the Caco-2/HT-29 monolayer of gallic acid from the alkaline fraction was higher (2.61 × 10−6 cm/s) than in the other fractions and similar to that obtained when tested pure (2.48 × 10−6 cm/s). In conclusion, mango peels contain bound phenolic compounds that, after their release, have permeability similar to pure compounds and exert an important CAA. This finding can be applied in the development of nutraceuticals using this important by-product from the mango processing industry. PMID:29419800

Rabbit Neonates and Human Adults Perceive a Blending 6-Component Odor Mixture in a Comparable Manner

PubMed Central

Sinding, Charlotte; Thomas-Danguin, Thierry; Chambault, Adeline; Béno, Noelle; Dosne, Thibaut; Chabanet, Claire; Schaal, Benoist; Coureaud, Gérard

2013-01-01

Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints. PMID:23341948

Structural studies of the O-specific polysaccharide(s) from the lipopolysaccharide of Azospirillum brasilense type strain Sp7.

PubMed

Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

2013-10-18

Lipopolysaccharide was obtained by phenol-water extraction from dried bacterial cells of Azospirillum brasilense type strain Sp7. Mild acid hydrolysis of the lipopolysaccharide followed by GPC on Sephadex G-50 resulted in a polysaccharide mixture, which was studied by composition and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy. The following polysaccharide structures were established, where italics indicate a non-stoichiometric (∼40%) 2-O-methylation of l-rhamnose. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sprayable low density ablator and application process

NASA Technical Reports Server (NTRS)

Sharpe, M. H.; Hill, W. E.; Simpson, W. G.; Carter, J. M.; Brown, E. L.; King, H. M.; Schuerer, P. H.; Webb, D. D. (Inventor)

1978-01-01

A sprayable, low density ablative composition is described consisting esentially of: (1) 100 parts by weight of a mixture of 25-65% by weight of phenolic microballoons, 0-20% by weight of glass microballoons, 4-10% by weight of glass fibers, 25-45% by weight of an epoxy-modified polyurethane resin, 2-4% by weight of a bentonite dispersing aid, and 1-2% by weight of an alcohol activator for the bentonite; (2) 1-10 parts by weight of an aromatic amine curing agent; and (3) 200-400 parts by weight of a solvent.

Mechanism of Action of Ribavirin: An Antiviral Drug of Military Importance,

DTIC Science & Technology

1980-06-01

was suspended in 120 mM Tris, 60 mM sodium ace- tate, 3 mM EDTA (pH 7.4) plus 10% glycerol and 0.1% bromophenol blue. Following electrophoresis, gels ... polyacryl - amide gels . J. Mol. Biol. 26:373-387. 2. Browne, M. J. 1979. Mechanism and specificity of action of ri- bavirin. Antimicrob. Agents...of 10 mM EDTA, 1% sodi- um dodecylsulfate (SDS) and 0.4 N sodium acetate (pH 5.2) then ex- tracted twice with a mixture of 50% phenol, 49% chloroform

Synergistic mixtures for control of slime-forming bacteria and other delete rious micro-organisms and processes using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tant, C.O.; Turner, N.E.; Bennett, E.O.

1969-09-30

Microbiocide compositions are described having a synergistic biocide effect on microorganisms, such as slime- forming bateria and other microorganisms considered to be deleterious or troublesome in water and especially in waterflooding operations, such as are used in the secondary recovery of petroleum oil in subterranean formations. The synergistic compositions consist of paired or multiple combinations of at least one of each of (1) compounds having furan, dihydrofuran or tetrahydrofuran nuclei, and (2) compounds having phenol nuclei or chloroanilines. (17 claims)

Interaction of gases with ablative composites. II - Water

NASA Technical Reports Server (NTRS)

Honeycutt, R. H., III; Wightman, J. P.

1974-01-01

An investigation was conducted to study the sorption of water on two ablative composites and their components as a function of pressure and temperature. A pressure range from 0.001 to 10 torr and a temperature range from 25 to 35 C were considered in the investigation. It was found that the sorption of water vapor by the ablative composites and their components varied directly with pressure. The components of the ablative composites included phenolic spheres, cork, a carbon-glass fiber mixture, glass spheres, silica fibers, and a silicone elastomer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, H.M.; Eskin, N.A.M.; Pinsky, C.

Potato polyphenol oxidase activity was strongly and noncompetitively inhibited by the 'Perov mixture' of coal tar components and by pyridine alone, while phenol competitively inhibited the enzyme. These two inhibitors are structural components of the parkinsonogenic neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). By extension, dopamine and neuromelanin synthesis in the brain may be influenced by the inhibitory effects of such compounds upon the copper-dependent steps of tyrosine metabolism. The non-animal model used in this study may represent an alternative to the use of animal tissues in neurodegenerative disease research.

Using Big Data Analytics to Address Mixtures Exposure

EPA Science Inventory

The assessment of chemical mixtures is a complex issue for regulators and health scientists. We propose that assessing chemical co-occurrence patterns and prevalence rates is a relatively simple yet powerful approach in characterizing environmental mixtures and mixtures exposure...

Ground-Based Aerosol Measurements

EPA Science Inventory

Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to ...

Indoor air-assessment: Indoor concentrations of environmental carcinogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gold, K.W.; Naugle, D.F.; Berry, M.A.

1991-01-01

In the report, indoor concentration data are presented for the following general categories of air pollutants: radon-222, environmental tobacco smoke (ETS), asbestos, gas phase organic compounds, formaldehyde, polycyclic aromatic hydrocarbons (PAH), pesticides, and inorganic compounds. These pollutants are either known or suspect carcinogens (i.e., radon-222, asbestos) or more complex mixtures or classes of compounds which contain known or suspect carcinogens. Concentration data for individual carcinogenic compounds in complex mixtures are usually far from complete. The data presented for complex mixtures often include compounds which are not carcinogenic or for which data are insufficient to evaluate carcinogenicity. Their inclusion is justified,more » however, by the possibility that further work may show them to be carcinogens, cocarcinogens, initiators or promotors, or that they may be employed as markers (e.g., nicotine, acrolein) for the estimation of exposure to complex mixtures.« less

Chemical Composition and In Vitro Cytotoxic Activity of Essential Oil of Leaves of Malus domestica Growing in Western Himalaya (India)

PubMed Central

Walia, Mayanka; Mann, Tavleen S.; Kumar, Dharmesh; Agnihotri, Vijai K.; Singh, Bikram

2012-01-01

Light pale-colored volatile oil was obtained from fresh leaves of Malus domestica tree, growing in Dhauladhar range of Himalaya (Himachal Pradesh, India), with characteristic eucalyptol dominant fragrance. The oil was found to be a complex mixture of mono-, sesqui-, di-terpenes, phenolics, and aliphatic hydrocarbons. Seventeen compounds accounting for nearly 95.3% of the oil were characterized with the help of capillary GC, GC-MS, and NMR. Major compounds of the oil were characterized as eucalyptol (43.7%), phytol (11.5%), α-farnesene (9.6%), and pentacosane (7.6%). Cytotoxicity of essential oil of leaves of M. domestica was evaluated by sulforhodamine B (SRB) assays. The essential oil of leaves of M. domestica, tested against three cancer cell lines, namely, C-6 (glioma cells), A549 (human lung carcinoma), CHOK1 (Chinese hamster ovary cells), and THP-1 (human acute monocytic leukemia cell). The highest activity showed by essential oil on C-6 cell lines (98.2%) at concentration of 2000 μg/ml compared to control. It is the first paper in literature to exploit the chemical composition and cytotoxic activity of leaves essential oil of M. domestica. PMID:22619691

Dentin biomodification potential depends on polyphenol source.

PubMed

Aguiar, T R; Vidal, C M P; Phansalkar, R S; Todorova, I; Napolitano, J G; McAlpine, J B; Chen, S N; Pauli, G F; Bedran-Russo, A K

2014-04-01

Although proanthocyanidins (PACs) modify dentin, the effectiveness of different PAC sources and the correlation with their specific chemical composition are still unknown. This study describes the chemical profiling of natural PAC-rich extracts from 7 plants using ultra high pressure/performance liquid chromatography (UHPLC) to determine the overall composition of these extracts and, in parallel, comprehensively evaluate their effect on dentin properties. The total polyphenol content of the extracts was determined (as gallic acid equivalents) using Folin-Ciocalteau assays. Dentin biomodification was assessed by the modulus of elasticity, mass change, and resistance to enzymatic biodegradation. Extracts with a high polyphenol and PAC content from Vitis vinifera, Theobroma cacao, Camellia sinensis, and Pinus massoniana induced a significant increase in modulus of elasticity and mass. The UHPLC analysis showed the presence of multiple types of polyphenols, ranging from simple phenolic acids to oligomeric PACs and highly condensed tannins. Protective effect against enzymatic degradation was observed for all experimental groups; however, statistically significant differences were observed between plant extracts. The findings provide clear evidence that the dentin bioactivities of PACs are source dependent, resulting from a combination of concentration and specific chemical constitution of the complex PAC mixtures.

Integrating qualitative and quantitative characterization of traditional Chinese medicine injection by high-performance liquid chromatography with diode array detection and tandem mass spectrometry.

PubMed

Xie, Yuan-yuan; Xiao, Xue; Luo, Juan-min; Fu, Chan; Wang, Qiao-wei; Wang, Yi-ming; Liang, Qiong-lin; Luo, Guo-an

2014-06-01

The present study aims to describe and exemplify an integrated strategy of the combination of qualitative and quantitative characterization of a multicomponent mixture for the quality control of traditional Chinese medicine injections with the example of Danhong injection (DHI). The standardized chemical profile of DHI has been established based on liquid chromatography with diode array detection. High-performance liquid chromatography coupled with time-of-flight mass spectrometry and high-performance liquid chromatography with electrospray multistage tandem ion-trap mass spectrometry have been developed to identify the major constituents in DHI. The structures of 26 compounds including nucleotides, phenolic acids, and flavonoid glycosides were identified or tentatively characterized. Meanwhile, the simultaneous determination of seven marker constituents, including uridine, adenosine, danshensu, protocatechuic aldehyde, p-coumaric acid, rosmarinic acid, and salvianolic acid B, in DHI was performed by multiwavelength detection based on high-performance liquid chromatography with diode array detection. The integrated qualitative and quantitative characterization strategy provided an effective and reliable pattern for the comprehensive and systematic characterization of the complex traditional Chinese medicine system. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of aromatic amino acids, phenylacetate and phenylpropionate on fermentation of xylan by the rumen anaerobic fungi, Neocallimastix frontalis and Piromyces communis.

PubMed

Guliye, A Y; Wallace, R J

2007-10-01

Anaerobic fungi are important members of the fibrolytic community of the rumen. The aim of this study was to study their requirement for aromatic amino acids (AA) and related phenyl acids (phenylpropionic and phenylacetic acids) for optimal xylan fermentation. Neocallimastix frontalis RE1 and Piromyces communis P were grown in a defined medium containing oat spelts xylan as the sole energy source, plus one of the following N sources: ammonia; ammonia plus a complete mixture of 20 AA commonly found in protein; ammonia plus complete AA mixture minus aromatic AA; ammonia plus phenyl acids; ammonia plus complete AA mixture without aromatic AA plus phenyl acids. Both species grew in all the media, indicating no absolute requirement for AA. The complete AA mixture increased (P<0.05) acetate concentration by 18% and 15%, sugar utilization by 33% and 22% and microbial yield by about 22% and 15% in N. frontalis and P. communis, respectively, in comparison with the treatments that had ammonia as the only N source. Neither the supply of aromatic AA or phenol acids, nor their deletion from the complete AA mixture, affected the fermentation rate, products or yield of either species. AA were not essential for N. frontalis and P. communis, but their growth on xylan was stimulated. The effects could not be explained in terms of aromatic AA alone. Ruminant diets should contain sufficient protein to sustain optimal fibre digestion by ruminal fungi. Aromatic AA or phenyl acids alone cannot replace the complete AA mixture.

Coupling in the absence of tertiary amines.

PubMed

Bodanszky, M; Bednarek, M A; Bodanszky, A

1982-10-01

In order to avoid base catalyzed side reactions during coupling, attempts were made to render superfluous the addition of tertiary amines to the reaction mixture. Weak acids were applied for the removal of acid labile protecting groups. Acetic acid and other carboxylic acids were considered unsuitable for this purpose coupling step. Pentachlorophenol and 2,4-dinitrophenol cleaved the Bpoc, Nps and Trt groups but more practical rates were reached with solutions of 1-hydroxybenzotriazole (HOBt) in trifluoroethanol, in acetic acid, or in a mixture of phenol and p-cresol. In addition to acidolysis, HOBt salts of amino components could also be obtained through hydrogenolysis of the Z group or thiolysis of the Nps group in the presence of HOBt, or by the displacement of acetic acid from acetate salts with HOBt. Acylation of HOBt salts of amino components with symmetrical or mixed anhydrides or with active esters did not require the addition of tertiary amine.

Chinese Herbal Medicines as Potential Agents for Alleviation of Heat Stress in Poultry

PubMed Central

MD Saadand, Salwani; Idrus, Zulkifli; Diao, Xiao Ping

2017-01-01

Heat stress negatively affects the productivity of chickens in commercial poultry farms in humid tropics. In this study, the concentrations and types of the antioxidant compounds of eight Chinese herbal medicines, which have previously demonstrated promising effects on suppressing heat stress as a mixture, were investigated using reversed-phase High Performance Liquid Chromatography, spectrophotometry, Liquid Chromatography Mass Spectrometry, and Gas-Liquid Chromatography. Our results provided the levels of phenolic compounds, total amounts of sugars, and total unsaturated fatty acids in the herbal extracts. Apart from the detection and quantification of the active ingredients of herbs that have the potential to mitigate heat stress in poultry, results of this study also provide useful data for developing an efficient and accurate formulation of the herbs' mixtures in order to induce positive effects against heat stress in in vivo studies. PMID:29209556

Antimocrobial Polymer

DOEpatents

McDonald, William F.; Huang, Zhi-Heng; Wright, Stacy C.

2005-09-06

A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

Gene expression changes in mononuclear cells in patients with metabolic syndrome after acute intake of phenol-rich virgin olive oil

PubMed Central

2010-01-01

Background Previous studies have shown that acute intake of high-phenol virgin olive oil reduces pro-inflammatory, pro-oxidant and pro-thrombotic markers compared with low phenols virgin olive oil, but it still remains unclear whether effects attributed to its phenolic fraction are exerted at transcriptional level in vivo. To achieve this goal, we aimed at identifying expression changes in genes which could be mediated by virgin olive oil phenol compounds in the human. Results Postprandial gene expression microarray analysis was performed on peripheral blood mononuclear cells during postprandial period. Two virgin olive oil-based breakfasts with high (398 ppm) and low (70 ppm) content of phenolic compounds were administered to 20 patients suffering from metabolic syndrome following a double-blinded, randomized, crossover design. To eliminate the potential effect that might exist in their usual dietary habits, all subjects followed a similar low-fat, carbohydrate rich diet during the study period. Microarray analysis identified 98 differentially expressed genes (79 underexpressed and 19 overexpressed) when comparing the intake of phenol-rich olive oil with low-phenol olive oil. Many of these genes seem linked to obesity, dyslipemia and type 2 diabetes mellitus. Among these, several genes seem involved in inflammatory processes mediated by transcription factor NF-κB, activator protein-1 transcription factor complex AP-1, cytokines, mitogen-activated protein kinases MAPKs or arachidonic acid pathways. Conclusion This study shows that intake of virgin olive oil based breakfast, which is rich in phenol compounds is able to repress in vivo expression of several pro-inflammatory genes, thereby switching activity of peripheral blood mononuclear cells to a less deleterious inflammatory profile. These results provide at least a partial molecular basis for reduced risk of cardiovascular disease observed in Mediterranean countries, where virgin olive oil represents a main source of dietary fat. Admittedly, other lifestyle factors are also likely to contribute to lowered risk of cardiovascular disease in this region. PMID:20406432

SOD activity and DNA binding properties of a new symmetric porphyrin Schiff base ligand and its metal complexes.

PubMed

Çay, Sevim; Köse, Muhammet; Tümer, Ferhan; Gölcü, Ayşegül; Tümer, Mehmet

2015-12-05

4-Methoxy-2,6-bis(hydroxymethyl)phenol (1) was prepared from the reaction of 4-methoxyphenol and formaldehyde. The compound (1) was then oxidized to the 4-methoxy-2,6-diformylphenol (2) compound. Molecular structure of compound (2) was determined by X-ray diffraction method. A new symmetric porphyrin Schiff base ligand 4-methoxy-2,6-bis[5-(4-iminophenyl)-10,15,20-triphenylporphyrin]phenol (L) was prepared from the reaction of the 5-(4-aminophenyl)-10,15,20-triphenylporphyrin (TTP-NH2) and the compound (2) in the toluene solution. The metal complexes (Cu(II), Fe(III), Mn(III), Pt(II) and Zn(II)) of the ligand (L) were synthesized and characterized by the spectroscopic and analytical methods. The DNA (fish sperm FSdsDNA) binding studies of the ligand and its complexes were performed using UV-vis spectroscopy. Additionally, superoxide dismutase activities of the porphyrin Schiff base metal complexes were investigated. Additionally, electrochemical, photoluminescence and thermal properties of the compounds were investigated. Copyright © 2015 Elsevier B.V. All rights reserved.

Flowering catch crops used as forage plants for dairy cows: influence on fatty acids and tocopherols in milk.

PubMed

Kälber, T; Meier, J S; Kreuzer, M; Leiber, F

2011-03-01

The effect of several flowering dicotyledonous catch crop plants (dicots) on milk fat quality in cows was investigated to test the hypothesis that their phenolic compounds may inhibit ruminal biohydrogenation and thus enhance the transfer to milk of intact, plant-derived polyunsaturated fatty acids. Berseem clover (Trifolium alexandrinum), buckwheat (Fagopyrum esculentum), and phacelia (Phacelia tanacetifolia) were sown in mixture with ryegrass (Lolium multiflorum; intended biomass proportion of 0.2) on 1ha. For comparison, nonflowering chicory (Cichorium intybus, also sown in mixture with ryegrass) and pure ryegrass were cultivated. Realized biomass proportions (wet weight) were 91% for berseem clover, 69% for buckwheat, 54% for phacelia, and 51% for chicory. At the start of flowering (or from d 47 after sowing onward), cultures were harvested daily and fed for 20 d ad libitum to groups of 6 midlactation cows each. Additionally, 1 kg each of energy and protein concentrate and pure ryegrass hay were fed. Individual intake and milk yield of the cows were measured daily. Milk samples were obtained twice daily 5 d before and from 11 to 20 d after the start of treatment feeding. Feed samples were drawn twice a week from the fresh feeds. Apart from standard traits, feeds and milk were analyzed for fatty acids, tocopherols, and phenolic fractions. Only a few substantial treatment effects on intake and performance were observed. All diets based on dicots increased α-linolenic acid (ALA) concentrations in milk fat compared with the ryegrass diet even though the corresponding swards were not generally richer in ALA. The highest ALA concentration in milk fat (1.3 g/100g of fatty acids) occurred with the berseem clover diet. Transfer rate of ALA from feed to milk was highest with the buckwheat diet (0.09) and lowest with ryegrass (0.05). This was congruent with the differences in total extractable phenols, being high in the buckwheat sward (2.6% of dry matter) and low in the ryegrass sward (1.2% of dry matter). Intermediates of ALA biohydrogenation were lowest in the milk fat of the buckwheat group, indicating an inhibitory effect of this treatment, which provided the highest dietary levels of phenols. The α-tocopherol concentration in milk was higher with the buckwheat diet than with berseem clover and phacelia diets. The study provides evidence that the ALA concentration in milk fat could be enhanced by feeding flowering dicots; however, this was due to different modes of action. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Complex mixtures, complex responses: Assessing pharmaceutical mixtures using field and laboratory approaches

USGS Publications Warehouse

Schoenfuss, Heiko L.; Furlong, Edward T.; Phillips, Patrick J.; Scott, Tia-Marie; Kolpin, Dana W.; Cetkovic-Cvrlje, Marina; Lesteberg, Kelsey E.; Rearick, Daniel C.

2016-01-01

Pharmaceuticals are present in low concentrations (<100 ng/L) in most municipal wastewater effluents but may be elevated locally because of factors such as input from pharmaceutical formulation facilities. Using existing concentration data, the authors assessed pharmaceuticals in laboratory exposures of fathead minnows (Pimephales promelas) and added environmental complexity through effluent exposures. In the laboratory, larval and mature minnows were exposed to a simple opioid mixture (hydrocodone, methadone, and oxycodone), an opioid agonist (tramadol), a muscle relaxant (methocarbamol), a simple antidepressant mixture (fluoxetine, paroxetine, venlafaxine), a sleep aid (temazepam), or a complex mixture of all compounds. Larval minnow response to effluent exposure was not consistent. The 2010 exposures resulted in shorter exposed minnow larvae, whereas the larvae exposed in 2012 exhibited altered escape behavior. Mature minnows exhibited altered hepatosomatic indices, with the strongest effects in females and in mixture exposures. In addition, laboratory-exposed, mature male minnows exposed to all pharmaceuticals (except the selective serotonin reuptake inhibitor mixture) defended nest sites less rigorously than fish in the control group. Tramadol or antidepressant mixture exposure resulted in increased splenic T lymphocytes. Only male minnows exposed to whole effluent responded with increased plasma vitellogenin concentrations. Female minnows exposed to pharmaceuticals (except the opioid mixture) had larger livers, likely as a compensatory result of greater prominence of vacuoles in liver hepatocytes. The observed alteration of apical endpoints central to sustaining fish populations confirms that effluents containing waste streams from pharmaceutical formulation facilities can adversely impact fish populations but that the effects may not be temporally consistent. The present study highlights the importance of including diverse biological endpoints spanning levels of biological organization and life stages when assessing contaminant interactions.

Transcriptional responses to complex mixtures - A review

EPA Science Inventory

Exposure of people to hazardous compounds is primarily through complex environmental mixtures, those that occur through media such as air, soil, water, food, cigarette smoke, and combustion emissions. Microarray technology offers the ability to query the entire genome after expos...

Coordination behavior of bis-phenolate saturated and unsaturated N-heterocyclic carbene ligands to zirconium: reactivity and activity in the copolymerization of cyclohexene oxide with CO2.

PubMed

Lalrempuia, Ralte; Breivik, Frida; Törnroos, Karl W; Le Roux, Erwan

2017-06-27

Tetravalent zirconium complexes supported by tridentate bis-phenolate imidazolidin-2-ylidene (L1), imidazol-2-ylidene (L2) and benzimidazol-2-ylidene (L3) NHC ligands were synthesized and evaluated as precursors for the copolymerization of cyclohexene oxide (CHO) with CO 2 . While the reactivity of the imidazolidinium [H 3 L1] chloride salt with Zr(OiPr) 4 (HOiPr), and subsequent ligand exchanges with either (CH 3 ) 3 SiCl or LiOiPr lead to a series of heteroleptic compounds (κ 3 -O,C,O-L1)Zr(X) 2 (THF) (X = Cl, OiPr), both imidazolium [H 3 L2] and benzimidazolium [H 3 L3] chloride salts give a mixture of homoleptic (κ 3 -O,C,O-NHC) 2 Zr and zwitterionic (κ 2 -O,O-HL)ZrCl 2 (OiPr) compounds along with traces or the absence of the heteroleptic intermediate (κ 3 -O,C,O-NHC)Zr(Cl)(OiPr)(THF). Such dissimilar reactivity between the unsaturated and saturated NHC ligands is predominantly ascribed to the increased acidity of azolium salts along with the π-donor strength of the C carbene in L2 and L3-Zr moieties. The reactivity with the more acidic azolium salts (H 3 L2/3) and the destabilized Zr-X trans to NHC carbene bond results in a significant increase in the amount of homoleptic compounds generating HCl. The released HCl reacts preferentially with the heteroleptic intermediates having non-planar NHC ligands (i.e. L2/3) promoting the formation of zwitterionic complexes. The in situ deprotonation of the isolated zwitterionic (κ 2 -O,O-HL3)ZrCl 2 (OiPr) compound by using Ag 2 O gives the homoleptic complex as the major component along with a bimetallic hydroxo-bridged [(κ 3 -O,C,O-L3)Zr(μ-OH)(OiPr)] 2 compound. Of particular interest is that only the heteroleptic NHC-Zr(iv) complexes were identified to be active and highly selective towards the copolymerization of CHO with CO 2 independently of the co-catalysts used (both anionic and neutral) under mild conditions (P CO 2 < 1 bar, T = 60 °C), and gave atactic and completely alternating copolymers in a controlled manner (M w /M n ≈ 1.3-1.8). In contrast, the isolated homoleptic, zwitterionic and bimetallic zirconium species were found to be inactive under similar reaction conditions. Although the activity found for NHC-Zr(iv) complexes is nearly of the same order of magnitude as that of the NHC-Ti(iv) analogues, these results are the first examples of tetravalent zirconium complexes achieving high selectivity (99% in PCHC) in the catalyzed copolymerization of CHO with CO 2 .

Production of o-diphenols by immobilized mushroom tyrosinase.

PubMed

Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio

2009-01-15

The o-diphenols 4-tert-butyl-catechol, 4-methyl-catechol, 4-methoxy-catechol, 3,4-dihydroxyphenylpropionic acid and 3,4-dihydroxyphenylacetic acid were produced from the corresponding monophenols (4-tert-butyl-phenol, 4-methyl-phenol, 4-methoxy-phenol, p-hydroxyphenylpropionic acid and p-hydroxyphenylacetic acid) using immobilized mushroom tyrosinase from Agaricus bisporus. In all cases the yield was R(diphenol)> or =88-96%, which, according to the literature, is the highest yield so far, obtained using tyrosinase. The reaction was carried out in 0.5M borate buffer pH 9.0 which was used to minimize the diphenolase activity of tyrosinase by complexing the o-diphenols generated. Hydroxylamine and ascorbic acid were also present in the reaction medium, the former being used to reduce mettyrosinase to deoxytyrosinase, closing the catalytic cycle, and the latter to reduce the o-quinone produced to o-diphenol. Inactivation of the tyrosinase by ascorbic acid was also minimized due to the formation of an ascorbic acid-borate complex. Concentrations of the o-diphenolic compounds obtained at several reaction times were determined by gas chromatography-mass spectrometry (GC-MS) and UV-vis spectroscopy. The experimental results are discussed.

Fact or artifact: the representativeness of ESI-MS for complex natural organic mixtures.

PubMed

Novotny, Nicole R; Capley, Erin N; Stenson, Alexandra C

2014-04-01

Because mass spectrometers provide their own dispersion and resolution of analytes, electrospray ionization mass spectrometry (ESI-MS) has become a workhorse for the characterization of complex mixtures from aerosols to crude oil. Unfortunately, ESI mass spectra commonly contain multimers, adducts and fragments. For the characterization of complex mixtures of unknown initial composition, this presents a significant concern. Mixed-multimer formation could potentially lead to results that bare no resemblance to the original mixture. Conversely, ESI-MS has continually reflected subtle differences between natural organic matter mixtures that are in agreement with prediction or theory. Knowing the real limitations of the technique is therefore critical to avoiding both over-interpretation and unwarranted skepticism. Here, data were collected on four mass spectrometers under a battery of conditions. Results indicate that formation of unrepresentative ions cannot entirely be ruled out, but non-covalent multimers do not appear to make a major contribution to typical natural organic matter spectra based on collision-induced dissociation results. Multimers also appear notably reduced when a cooling gas is present in the accumulation region of the mass spectrometer. For less complex mixtures, the choice of spray solvent can make a difference, but generally spectrum cleanliness (i.e. representativeness) comes at the price of increased selectivity. Copyright © 2014 John Wiley & Sons, Ltd.

Antibacterial, antioxidant and anti-proliferative properties and zinc content of five south Portugal herbs.

PubMed

Nunes, Ricardo; Pasko, Pawel; Tyszka-Czochara, Malgorzata; Szewczyk, Agnieszka; Szlosarczyk, Marek; Carvalho, Isabel S

2017-12-01

Crataegus monogyna L. (Rosaceae) (CM), Equisetum telmateia L. (Equisataceae) (ET), Geranium purpureum Vil. (Geraniaceae) (GP), Mentha suaveolens Ehrh. (Lamiaceae) (MS), and Lavandula stoechas L. spp. luisieri (Lamiaceae) (LS) are all medicinal. To evaluate the antioxidant, antiproliferative and antimicrobial activities of plant extracts and quantify individual phenolics and zinc. Aerial part extracts were prepared with water (W), ethanol (E) and an 80% mixture (80EW). Antioxidant activity was measured with TAA, FRAP and RP methods. Phenolics were quantified with a HPLC. Zinc was quantified using voltammetry. Antibacterial activity (after 48 h) was tested using Enterococcus faecalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. Antiproliferative activity (after 24 h) was tested using HEP G2 cells and fibroblasts. Solvents influenced results; the best were E and 80EW. GP had the highest antioxidant activity (TAA and FRAP of 536.90 mg AAE/g dw and 783.48 mg TE/g dw, respectively). CM had the highest zinc concentration (37.21 mg/kg) and phenolic variety, with neochlorogenic acid as the most abundant (92.91 mg/100 g dw). LS was rich in rosmarinic acid (301.71 mg/100 g dw). GP and LS inhibited the most microorganisms: B. cereus, E. coli and S. aureus. GP also inhibited E. faecalis. CM had the lowest MIC: 5830 μg/mL. The antibacterial activity is explained by the phenolics present. LS and CM showed the most significant anti-proliferative activity, which is explained by their zinc content. The most promising plants for further studies are CM, LS and GP.

Fungal degradation of wood lignins: Geochemical perspectives from CuO-derived phenolic dimers and monomers

NASA Astrophysics Data System (ADS)

Goñi, Miguel A.; Nelson, Bryan; Blanchette, Robert A.; Hedges, John I.

1993-08-01

The elemental compositions and yields of CuO-derived phenol dimers and monomers from woods degraded by different fungi under laboratory and natural conditions were compared to those from undegraded controls. In laboratory experiments, white-rot fungi caused pronounced mass losses, lowered the organic carbon content of the remnant woods, and decreased the absolute carbon-normalized yields of the major classes of lignin phenol dimers and monomers. White-rot decay induced large losses of some CuO reaction products, such as (β,1-diketone and α,l-monoketone dimers and syringyl monomers, and increased the absolute yields of individual acidic reaction products, such as dehydrodivanillic acid, vanillic acid, and 2-syringylsyringic acid. In contrast, the brown-rot fungus, Fomitopsis pinicola, was less efficient in decaying lignin, inducing lower absolute lignin phenol losses and, in some cases, increasing the organic carbon content of remnant woods. Several lignin constituents, mainly carboxyvanillyl monomers and α,2-methyl and α,5-monoketone dimers, were produced during brown-rot degradation. Similar diagenetic trends were also apparent in the five woods collected from the field, suggesting the differences between white- and brown-rot decay are still apparent after more extensive degradation in natural environments. The lignin compositions from a selected set of previously analyzed sedimentary mixtures were generally consistent with the diagenetic trends observed in both laboratory and field samples. In some cases, however, geochemical parameters such as elevated dimer/monomer and carboxyvanillyl/ vanillyl monomer ratios clearly distinguished certain sedimentary lignins. In these samples, other processes, such as extensive fungal decay, bacterial degradation, or a nonwoody vascular plant origin, could be important factors affecting lignin compositions.

Lignin phenols used to infer organic matter sources to Sepetiba Bay - RJ, Brasil

NASA Astrophysics Data System (ADS)

Rezende, C. E.; Pfeiffer, W. C.; Martinelli, L. A.; Tsamakis, E.; Hedges, J. I.; Keil, R. G.

2010-04-01

Lignin phenols were measured in the sediments of Sepitiba Bay, Rio de Janeiro, Brazil and in bedload sediments and suspended sediments of the four major fluvial inputs to the bay; São Francisco and Guandu Channels and the Guarda and Cação Rivers. Fluvial suspended lignin yields (Σ8 3.5-14.6 mgC 10 g dw -1) vary little between the wet and dry seasons and are poorly correlated with fluvial chlorophyll concentrations (0.8-50.2 μgC L -1). Despite current land use practices that favor grassland agriculture or industrial uses, fluvial lignin compositions are dominated by a degraded leaf-sourced material. The exception is the Guarda River, which has a slight influence from grasses. The Lignin Phenol Vegetation Index, coupled with acid/aldehyde and 3.5 Db/V ratios, indicate that degraded leaf-derived phenols are also the primary preserved lignin component in the bay. The presence of fringe Typha sp. and Spartina sp. grass beds surrounding portions of the Bay are not reflected in the lignin signature. Instead, lignin entering the bay appears to reflect the erosion of soils containing a degraded signature from the former Atlantic rain forest that once dominated the watershed, instead of containing a significant signature derived from current agricultural uses. A three-component mixing model using the LPVI, atomic N:C ratios, and stable carbon isotopes (which range between -26.8 and -21.8‰) supports the hypothesis that fluvial inputs to the bay are dominated by planktonic matter (78% of the input), with lignin dominated by leaf (14% of the input) over grass (6%). Sediments are composed of a roughly 50-50 mixture of autochthonous material and terrigenous material, with lignin being primarily sourced from leaf.

Antioxidant capacities and total phenolic contents of 20 polyherbal remedies used as tonics by folk healers in Phatthalung and Songkhla provinces, Thailand.

PubMed

Chanthasri, Wipawee; Puangkeaw, Nuntitporn; Kunworarath, Nongluk; Jaisamut, Patcharawalai; Limsuwan, Surasak; Maneenoon, Katesarin; Choochana, Piyapong; Chusri, Sasitorn

2018-02-21

Uses of polyherbal formulations have played a major role in traditional medicine. The present study is focused on the formulations used in traditional Thai folkloric medicine as tonics or bracers. Twenty documented polyherbal mixtures, used as nourishing tonics by the folk healers in Phatthalung and Songkhla provinces in southern Thailand, are targeted. Despite traditional health claims, there is no scientific evidence to support the utilization of polyherbal formulations. The phenolic and flavonoid contents of the polyherbal formulations and a series of antioxidant tests were applied to measure their capability as preventive or chain-breaking antioxidants. In addition, the cytotoxic activity of effective formulations was assayed in Vero cells. Ninety-eight plant species belonging to 45 families were used to prepare the tested formulation. The preliminary results revealed that water extracts of THP-R016 and THP-R019 contain a high level of total phenolic and flavonoid contents and exhibit remarkable antioxidant activities, as tested by DPPH, ABTS, and FRAP assays. The extract of THP-R019 also showed the strongest metal chelating activities, whereas THP-R016 extract possessed notable superoxide anion and peroxyl radical scavenging abilities. The data provide evidence that the water extracts of folkloric polyherbal formulations, particularly THP-R016, are a potential source of natural antioxidants, which will be valuable in the pharmaceutical and nutraceutical industries. The free radical scavenging of THP-R016 may be due to the contribution of phenolic and flavonoid contents. Useful characteristics for the consumer, such as the phytochemical profiles of active ingredients, cellular based antioxidant properties and beneficial effects in vivo, are under further investigation.

Supercritical separation process for complex organic mixtures

DOEpatents

Chum, H.L.; Filardo, G.

1990-10-23

A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70 C and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution. 1 fig.

Improvement of simultaneous Cr(VI) and phenol removal by an immobilised bacterial consortium and characterisation of biodegradation products.

PubMed

Ontañon, Ornella M; González, Paola S; Barros, Germán G; Agostini, Elizabeth

2017-07-25

Microbial bioremediation emerged some decades ago as an eco-friendly technology to restore polluted sites. Traditionally, the search for microorganisms suitable for bioremediation has been based on the selection of isolated strains able to remove a specific type of pollutant. However, this strategy has now become obsolete, since co-pollution is a global reality. Thus, current studies attempt to find bacterial cultures capable of coping with a mixture of organic and inorganic compounds. In this sense, the bacterial consortium SFC 500-1 has demonstrated efficiency for Cr(VI) and phenol removal, both of which are found in many industrial wastewaters. In the present study, the ability of SFC 500-1 for simultaneous removal was improved through its entrapment in a Ca-alginate matrix. This strategy led to an increased removal of Cr(VI), which was partially reduced to Cr(III). Immobilised cells were able to tolerate and degrade phenol up to 1,500mg/l at high rates, forming catechol and cis,cis-muconate as oxidation intermediates. Successful removal potential through 5 cycles of reuse, as well as after long-term storage, was another important advantage of the immobilised consortium. These characteristics make SFC 500-1 an interesting system for potential application in the biotreatment of co-polluted effluents. Copyright © 2017. Published by Elsevier B.V.

Pineapple peel wastes as a potential source of antioxidant compounds

NASA Astrophysics Data System (ADS)

Saraswaty, V.; Risdian, C.; Primadona, I.; Andriyani, R.; Andayani, D. G. S.; Mozef, T.

2017-03-01

Indonesia is a large pineapple (Ananas comosus) producing country. Food industries in Indonesia processed this fruit for new products and further resulted wastes of which cause an environmental problems. Approximately, one pineapple fruit total weight is 400 gr of which 60 g is of peel wastes. In order to reduce such pineapple peel wastes (PPW), processing to a valuable product using an environmentally friendly technique is indispensable. PPW contained phenolic compound, ferulic acid, and vitamin A and C as antioxidant. This study aimed to PPW using ethanol and water as well as to analyze its chemical properties. Both dried and fresh PPW were extracted using mixtures of ethanol and water with various concentrations ranging from 15 to 95% (v/v) at room temperature for 24 h. The chemical properties, such as antioxidant activity, total phenolic content (Gallic acid equivalent/GAE), and total sugar content were determined. The results showed that the range of Inhibition Concentration (IC)50 value as antioxidant activity of extracts from dried and fresh PPW were in the range of 0.8±0.05 to 1.3±0.09 mg.mL-1 and 0.25±0.01 to 0.59±0.01 mg.mL-1, respectively, with the highest antioxidant activity was in water extract. The highest of total phenolic content of 0.9 mg.g-1 GAE, was also found in water extract.

Characterization and Influence of Green Synthesis of Nano-Sized Zinc Complex with 5-Aminolevulinic Acid on Bioactive Compounds of Aniseed.

PubMed

Tavallali, Vahid; Rahmati, Sadegh; Rowshan, Vahid

2017-11-01

A new water soluble zinc-aminolevulinic acid nano complex (n[Zn(ALA) 2 ]), which was characterized by TEM, IR, and EDX spectra, has been prepared via sonochemical method under green conditions in water. In the current study, the effectiveness of foliar Zn amendment using synthetic Zn-ALA nano complex, as a new introduced Zn-fertilizer here, was evaluated. As the model plant, Pimpinella anisum, the most valuable spice and medicinal plant grown in warm regions, was used. By using zinc nano complex, further twenty compounds were obtained in the essential oil of anise plants. Application of 0.2% (w/v) Zn-ALA nano complex increased the levels of (E)-anethole, β-bisabolene, germacrene D, methyl chavicol, and α-zingiberene in the essential oil. Nano Zn complex at the rate of 0.2% induced considerable high phenolic compounds and zinc content of shoots and seeds. Chlorogenic acid had the highest level between four detected phenolic compounds. The maximum antioxidant activity was monitored through the application of Zn nano complex. According to the results, nanoscale nutrients can be provided with further decreased doses for medicinal plants. Using Zn-ALA nano complex is a new and efficient method to improve the pharmaceutical and food properties of anise plants. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Toward the Rational Use of Exposure Information in Mixtures Toxicology

EPA Science Inventory

Of all the disciplines of toxicology, perhaps none is as dependent on exposure information as Mixtures Toxicology. Identifying real world mixtures and replicating them in the laboratory (or in silico) is critical to understanding their risks. Complex mixtures such as cigarett...

Differences between the N·H·O and O·H·O hydrogen bonds in complexes of 2,6-dichloro-4-nitrophenol with pyridines and pyridine N-oxides

NASA Astrophysics Data System (ADS)

Dega-Szafran, Zofia; Kania, Anna; Grundwald-Wyspiańska, Monika; Szafran, Mirosław; Tykarska, Ewa

1996-07-01

Complexes of five pyridines and nine pyridine N-oxides with 2,6-dichloro-4-nitrophenol (DCNP) in solution and the solid state were studied by Fourier transform IR and UV spectroscopy, by quantum-mechanical calculations with the semiempirical parametric method 3 (PM3) and by X-ray analysis. The crystals of the 1 : 1 complex of 4-methoxy-2,6-dimethylpyridine N-oxide with DCNP are monoclinic, space group {P2 1}/{n}, a = 4.5936(5) Å, b = 21.953(3) Å, c = 15.664(2) Å, β = 92.87(1)°, V = 1577.6(8) Å3, Z = 4. The molecules of the complex are joined together by an N +OH⋯O - hydrogen bond with an O⋯O distance of 2.425(3) Å, a CO - distance of 1.286(3) Å and a (N +O)H⋯O - angle of 152.9°. The PM3 method predicts for all the investigated complexes two minima, the deeper one for B⋯HA complexes and the shallower one for the B +H⋯A - forms. For the 4-methylpyridine complex the N +H⋯O - distance is reproduced correctly but for the 4-methoxy-2,6-dimethylpyridine N-oxide complex the N +H⋯O - distance is too long. The predicted hydrogen-bond angles differ from the experimental values by more than 10°. In solid state complexes of pyridines the N⋯O distances and the broad absorption due to a protic vibration are not directly related to Δp Ka. This is due to the crystal packing forces. In solution the broad absorption varies with Δp Ka. A band in the 3500 cm -1 region due to the solvated phenol is present in all investigated complexes in solution. Absorption in the 3000-2000 cm -1 region of pyridine complexes is more intense than that of the pyridine N-oxides, in agreement with the difference in N⋯O and NO⋯O distances. The broad absorption in the spectra of pyridine complexes is more influenced by solvent effects than in the pyridine N-oxide complexes. The UV spectra of the pyridine complexes show two bands due to B⋯HA (305-315 nm) and B +H⋯A - (382-395 nm) forms. The UV spectra of complexes of pyridine N-oxides of intermediate strengths in CH 2Cl 2 are not combinations of the spectra of phenol and phenolate. The band in the intermediate position denotes that neither species close to phenol nor to phenoxide ion is present. In these complexes the proton is probably localized in a single minimum and the minimum moves from the donor to the acceptor or, what is more probable, reorganization of the solvent molecules around the complex is faster than the time range of UV spectroscopy. In acetonitrile the situation is quite different as two bands are present, in agreement with a prototropic equilibrium. Effects of solvent, concentration and stoichiometry on interactions of DCNP with pyridines and pyridine N-oxides are compared and discussed. An extended mechanism of the proton-transfer reaction is proposed.

Fate and transport of phenol in a packed bed reactor containing simulated solid waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saquing, Jovita M., E-mail: jmsaquing@gmail.com; Knappe, Detlef R.U., E-mail: knappe@ncsu.edu; Barlaz, Morton A., E-mail: barlaz@ncsu.edu

Highlights: Black-Right-Pointing-Pointer Anaerobic column experiments were conducted at 37 Degree-Sign C using a simulated waste mixture. Black-Right-Pointing-Pointer Sorption and biodegradation model parameters were determined from batch tests. Black-Right-Pointing-Pointer HYDRUS simulated well the fate and transport of phenol in a fully saturated waste column. Black-Right-Pointing-Pointer The batch biodegradation rate and the rate obtained by inverse modeling differed by a factor of {approx}2. Black-Right-Pointing-Pointer Tracer tests showed the importance of hydrodynamic parameters to improve model estimates. - Abstract: An assessment of the risk to human health and the environment associated with the presence of organic contaminants (OCs) in landfills necessitates reliable predictivemore » models. The overall objectives of this study were to (1) conduct column experiments to measure the fate and transport of an OC in a simulated solid waste mixture, (2) compare the results of column experiments to model predictions using HYDRUS-1D (version 4.13), a contaminant fate and transport model that can be parameterized to simulate the laboratory experimental system, and (3) determine model input parameters from independently conducted batch experiments. Experiments were conducted in which sorption only and sorption plus biodegradation influenced OC transport. HYDRUS-1D can reasonably simulate the fate and transport of phenol in an anaerobic and fully saturated waste column in which biodegradation and sorption are the prevailing fate processes. The agreement between model predictions and column data was imperfect (i.e., within a factor of two) for the sorption plus biodegradation test and the error almost certainly lies in the difficulty of measuring a biodegradation rate that is applicable to the column conditions. Nevertheless, a biodegradation rate estimate that is within a factor of two or even five may be adequate in the context of a landfill, given the extended retention time and the fact that leachate release will be controlled by the infiltration rate which can be minimized by engineering controls.« less