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Literatura académica sobre el tema "Phenols compounds"

Autor: Grafiati

Publicado: 10 de marzo de 2023

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Artículos de revistas sobre el tema "Phenols compounds"

Brezani, Viliam, Karel Smejkal, Jan Hosek y Veronika Tomasova. "Anti-inflammatory Natural Prenylated Phenolic Compounds - Potential Lead Substances". Current Medicinal Chemistry 25, n.º 10 (9 de abril de 2018): 1094–159. http://dx.doi.org/10.2174/0929867324666170810161157.

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Background: Natural phenolics are secondary plant metabolites, which can be divided into several categories with the common structural feature of phenolic hydroxyl. The biological activity of phenolics is often modified and enhanced by prenylation by prenyl and geranyl; higher terpenoid chains are rare. The type of prenyl connection and modification affects their biological activity. Objective: This review summarizes information about prenylated phenols and some of their potential sources, and provides an overview of their anti-inflammatory potential in vitro and in vivo. Method: The literature search was performed using SciFinder and keywords prenyl, phenol, and inflammation. For individual compounds, an additional search was performed to find information about further activities and mechanisms of effects. Result: We summarized the effects of prenylated phenolics in vitro in cellular or biochemical systems on the production and release of inflammation-related cytokines; their effects on inhibition of cyclooxygenases and lipoxygenases; the effects on production of nitric oxide, antiradical and antioxidant activity; and the effect on the inhibition of the release of enzymes and mediators from neutrophils, mast cells and macrophages. The information about the antiphlogistic potential of prenylated phenolics is further supported by a review of their action in animal models. Conclusion: Almost 400 prenylated phenols were reviewed to overview their antiinflammatory effect. The bioactivity of several prenylated phenols was confirmed also using in vivo assays. A pool of natural prenylated phenols represents a source of inspiration for synthesis, and prenylated phenols as components of various medicinal plants used to combat inflammation could be their active principles.

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Shi, Zhen Jing, Meng Xiang Fang, Chun Guang Zhou, Shu Rong Wang y Zhong Yang Luo. "Studies on the Extraction of Phenols from Coal Tar Produced in Multi-Generation System". Advanced Materials Research 347-353 (octubre de 2011): 673–77. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.673.

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Isolation of phenols from the middle oil fraction(170-230°C) of tar produced in the multi-cogeneration system has been investigated for the purpose of recovering valuable pure phenols, such as phenol, cresols, xylenol and ethyl-phenol. Phenolic compounds were separated from the middle oil by liquid-liquid extraction using alkali and sulfuric acid. The yield of phenolic fraction from the middle oil (170-230°C) is up to 37%, which is much higher compared with those of metallurgical coke plants. Chromatography-mass spectrometry was used to analyse phenolic compounds. The result shows that the phenol content is less than 2%, and main compounds are cresol(14%), xylenol(20%) . Phenols of the middle oil fraction(230-280°C) was also analysed, which main contain methyl naphthol(20%).

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Muráriková, A., K. Kaffková, S. Raab y J. Neugebauerová. "Evaluation of content of phenolics in Salvia species cultivated in South Moravian Region / Hodnotenie obsahu fenolov vo vybraných druhoch rodu Salvia L. pestovaných v Juhomoravskom kraji". Acta Facultatis Pharmaceuticae Universitatis Comenianae 62, s9 (1 de junio de 2015): 18–22. http://dx.doi.org/10.1515/afpuc-2015-0007.

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Abstract In this study, total phenolic content (TPC) and rosmarinic acid (RA) of 37 samples sage (Salvia L.) of extracts were determined using spectrophotometric methods. The amount of total phenols was analysed with Folin-Ciocalteu reagents. Gallic acid was used as a standard compound and the total phenols were expressed as mg.g−1 gallic acid equivalents of dried plant material. The values of the extracts displayed substantial differences. All of the investigated species except Salvia jurisicii (990.79 mg GAE. g−1 d.w.) exhibited higher content of phenolics. Among the studies, species demonstrated the highest content of phenol, followed in sequence by Salvia tomentosa, Salvia fruticosa, Salvia triloba, Salvia officinalis ‘Extrakta’, Salvia officinalis. TPC varied from 990.79 to 4459.88 mg GAE. g−1 d.w. in the extracts. The total amount of RA was between 0.88 and 8.04% among species. Salvia tomentosa, Salvia verticillata and Salvia officinalis ‘Extrakta’ had the highest content of RA. The high content of phenolic compounds indicated that these compounds contribute to the antioxidant activity.

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Mikulic Petkovsek, M., F. Stampar y R. Veberic. "Seasonal changes in phenolic compounds in the leaves of scab-resistant and susceptible apple cultivars". Canadian Journal of Plant Science 89, n.º 4 (1 de julio de 2009): 745–53. http://dx.doi.org/10.4141/cjps08202.

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Leaf samples were collected from apple varieties susceptible and resistant to apple scab [Venturia inaequalis (Cke.) Wint.] from June to September for 2 yr between 2005 and 2006. These were analyzed for phenolic compounds, using high-performance liquid chromatography (HPLC). In the apple leaves, the following hydroxycinnamic acids were detected: chlorogenic, caffeic and p-coumaric acids; the following dihydrochalcone: phloridzin, and the following flavonoids: epicatechin, catechin, rutin and quercitrin. The total of phenolic compounds in apple leaves was determined spectrophotometrically, using the Folin-Ciocalteu method. During the growing season, the content of phenolic compounds changed and was related to the physiological stage of the tissue and cultivar used. Each phenolic compound had its own curve of seasonal changes in concentration. In 2005 there was no significant change in total phenols during the growing season. In 2006, their content changed significantly during the growing season; statistically the highest content of total phenols was found in the leaves in August. Total phenols as well as single phenolics were statistically higher in resistant than in susceptible apple varieties for both years.Key words: Malus × domestica Borkh., leaves, phenolic compounds, seasonal changes, Venturia inaequalis (Cke.) Wint., resistance

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Sithole, Bishop B. y David T. Williams. "Halogenated Phenols in Water at Forty Canadian Potable Water Treatment Facilities". Journal of AOAC INTERNATIONAL 69, n.º 5 (1 de septiembre de 1986): 807–10. http://dx.doi.org/10.1093/jaoac/69.5.807.

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Abstract Samples of raw and treated water were collected once in each of 3 seasons at 40 potable water treatment plants across Canada and were analyzed for phenol and 33 halogenated phenolic compounds including chlorophenols, bromophenols, bromochlorophenols, and chloroguaiacols. Eighteen of the compounds were not found at any treatment plant; phenol and each of the remaining halogenated phenols were found in at least 1 sample. Pentachlorophenol was the only halogenated phenolic compound found in more than 20% of the raw water samples in the fall and winter samples at levels up to 53 ng/L with mean values of 1.9 and 2.8 ng/L, respectively. No halogenated phenols were detected in raw water summer samples. The halogenated phenols found most frequently in treated water samples were 4-chloro-, 2,4-dichloro-, 2,4,6- trichloro-, and bromodichlorophenols. Mean values were less than 15 ng/L and maximum values seldom exceeded 100 ng/L. Most of the positive values for the treated water samples were found at 8 of the 40 treatment plants but no correlations could be found between halogenated phenol levels and raw water type, treatment process, or chemical dosages.

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van Gorsel, Hendrik y Adel A. Kader. "PHENOLIC METABOLISM AND INTERNAL BREAKDOWN (CHILLING INJURY) OF PEACH FRUIT". HortScience 25, n.º 11 (noviembre de 1990): 1356H—1357. http://dx.doi.org/10.21273/hortsci.25.11.1356.

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Internal breakdown (IB) is the limiting factor in the storage and postharvest handling of stone fruits. The symptoms of IB appear when fruits are kept for prolonged periods at temperatures below 10C and include leatheriness, mealiness, browning and bleeding of the flesh, and failure to ripen normally. We investigated the changes in phenolic compounds associated with IB of stone fruits. Twenty-eight phenolic compounds were separated by HPLC. Ten of these components were significantly affected by chilling temperatures. The concentration of six phenols changed in response to ripening after chilling temperatures, parallel to the appearance of IB symptoms. Most phenols showed a concentration gradient from the inside to the outside of the fruit, Comparison between peach cultivars showed characteristic differences in phenol metabolism during ripening. In both cultivars the most predominant phenol, chlorogenic acid, showed little change in concentration during storage. The structure of key phenolic compounds will be determined in order to elucidate the biochemical relationship between the phenols and the related enzymes. In this respect, a method was developed to detect phenylalanine ammonia-lyase (PAL) activity in peach fruit.

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Martín, Carlos, Helene B. Klinke, Marcelo Marcet, Luis García, Ena Hernández y Anne Belinda Thomsen. "Study of the phenolic compounds formed during pretreatment of sugarcane bagasse by wet oxidation and steam explosion". Holzforschung 61, n.º 5 (1 de agosto de 2007): 483–87. http://dx.doi.org/10.1515/hf.2007.106.

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Abstract The formation of phenolic compounds during pretreatment of sugarcane bagasse was investigated. Bagasse was pretreated by wet oxidation (WO) at 195°C during 15 min under either alkaline or acidic conditions and by steam explosion (STEX) at 205°C during 10 min. The total content of phenolic compounds in the prehydrolysates was determined spectrophotometrically. Under acidic and alkaline WO conditions, 3.8% (w/w) and 3% phenols were found, respectively. STEX gave rise to 1.9% phenols. Individual phenols were identified by GC-MS. Phenylpropanoid derivatives, such as p-coumaric and ferulic acids, accounted for more than 50% of the phenols identified in STEX prehydrolysates. In WO prehydrolysates, on the other hand, phenols lacking the propanoid side chain were predominant. Of the latter, p-hydroxybenzaldehyde was the most abundant phenol, with concentrations of 0.27% (acidic conditions) and 0.15% (alkaline conditions). As expected, high concentrations of oxidised compounds were generally observed in WO prehydrolysates, such as carboxylic acids, aldehydes and ketones. This is a true reflection of the oxidative conditions during WO pretreatment.

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Kochana, Jolanta, Juliusz Adamski y Andrzej Parczewski. "A Critical View on the Phenol Index as a Measure of Phenol Compounds Content in Waters. Application of a Biosensor". Ecological Chemistry and Engineering S 19, n.º 3 (1 de enero de 2012): 383–91. http://dx.doi.org/10.2478/v10216-011-0028-5.

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A Critical View on the Phenol Index as a Measure of Phenol Compounds Content in Waters. Application of a BiosensorPhenol index is considered as an important indicator of water purity and quality. Usually phenol index is determined by a spectrophotometric method the calibration being based on phenol standards. Unfortunately, the absorptivities of different phenols compounds differ from each other. This leads to significant uncertainty concerning content of phenols in water. It is shown that the same shortage of the phenol index appears also if it is determined using an amperometric biosensor based on tyrosinase. The sensitivity of the biosensor response to four phenol compounds: phenol, catechol, 3-cresol and 4-chlorophenol was examined, as well as possible interactions between phenols, according to 24factorial experiment. It was proved that individual phenols affect phenol index independently from each other,ieno significant interaction between phenols was detected. However, sensitivity of the biosensor to different phenols is not the same. Relationship between phenol index and concentrations of phenols in water is discussed.

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Smith, Terrence J., Ross H. Wearne y Adrian F. A. Wallis. "Characteristics of the Chlorinated Organic Substances in Filtrates from Bleaching of Oxygen-Delignified Eucalypt Kraft Pulp". Water Science and Technology 29, n.º 5-6 (1 de marzo de 1994): 61–71. http://dx.doi.org/10.2166/wst.1994.0702.

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Oxygen-delignified kraft pulps from mature and young eucalypt woods were bleached with sequences involving chlorine (C), chlorine dioxide (D) and alkali-oxygen (EO). The bleaching filtrates were analysed for chlorinated organic compounds by gas chromatography with the use of a mass selective detector. Chlorinated compounds found included a range of chlorinated phenols, neutral compounds, aliphatic acids and phenolic acids. A total of 41 chlorinated phenols were identified, mostly in the filtrates following chlorination {(EO)[C]} and only few in the (EO)[D] filtrates. 2-Chlorosyringaldehyde was the only significant chlorinated phenol obtained after D-prebleaching. There was no indication of differences in the types of chlorinated phenols obtained from the mature and young eucalypt samples, although there were higher levels of phenols in filtrates from the younger wood sample. The dominant chlorinated neutral compounds found in the filtrates were chloroform, chloroacetones and chlorodimethylsulfones. Most chloroform and chloroacetones were found in the C-stage filtrates, while chlorodimethylsulfones were found in both C and D-stage filtrates to the same extent. An abundant compound with probable molecular formula C5H3ClO3 was also in the neutral fraction. The chloroacetic acids were the only aliphatic acids detected and were found in all filtrates examined. A method for the analysis of chlorinated phenolic acids involving sequential acetylation and methylation of the extracts was devised. Three chlorinated phenolic acids were identified in the filtrates as their methyl ester acetates. The total amount of chlorinated compounds analysed was consistently higher in the young eucalypt sample than in the mature sample, and correlated well with the generic parameters AOX and EOX. High molar mass (HMM) solids prepared from the C(EO) bleaching filtrates by ultrafiltration had higher chlorine contents than those from the D(EO) bleaching filtrates. Apparent molecular mass distributions of the HMM solids determined by high performance size exclusion chromatography were dependent on the method of detection.

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Meza-Escalante, Edna R., Larissa Lepe-Martinié, Carlos Díaz-Quiroz, Denisse Serrano-Palacios, Luis H. Álvarez-Valencia, Ana Rentería-Mexía, Pablo Gortáres-Moroyoqui y Gabriela Ulloa-Mercado. "Capacity of Marine Microalga Tetraselmis suecica to Biodegrade Phenols in Aqueous Media". Sustainability 14, n.º 11 (30 de mayo de 2022): 6674. http://dx.doi.org/10.3390/su14116674.

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Phenolic compounds are toxic and dangerous to the environment and human health. Although the removal of phenols and their derivatives is very difficult, it has been achieved by applying some biological processes. The capacity of microalga to remove phenolic compounds has been demonstrated; however, few reports of the removal of these compounds in a mixture have been published. The removal of phenol, p-cresol and o-cresol was performed by batch kinetics at 50 and 100 mg L−1, and the simultaneous degradation of phenol, p-cresol and o-cresol was carried out in a mixture at 40 mg L−1 using the marine microalga Tetraselmis suecica. The kinetic study was carried out for 192 h. For concentrations of 50 mg L−1 and 100 mg L−1, phenolic compound consumption efficiencies greater than 100% and 85%, respectively, were obtained, and up to 73.6% removal in the mixture. The results obtained indicate that the marine microalga carries out a process of the oxidation of organic matter and phenolic compounds, mineralizing up to 31.4% to CO2 in the mixture. Biological treatments using the marine microalga T. suecica can be considered feasible to treat effluents with concentrations similar to those of the present study.

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Más fuentes

Tesis sobre el tema "Phenols compounds"

Zhu, Fan y 朱帆. "Interactions of carbohydrates with phenolic compounds". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45584710.

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Rubió, Piqué Laura. "Phenol-enriched olive oil with its own phenolic compounds and complemented with phenols from thyme: a functional food development model". Doctoral thesis, Universitat de Lleida, 2014. http://hdl.handle.net/10803/146133.

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L'enriquiment de l’oli d'oliva amb els seus propis fenols esdevé una estratègia interessant per augmentar i normalitzar la ingesta diària d’hidroxitirosol sense augmentar el consum calòric. No obstant això, olis amb alt contingut fenòlic proporcionen un gust amarg que podria provocar rebuig entre els consumidors. A més, altes dosis d'hidroxitirosol podria tenir una acció pro-oxidant. En aquesta tesi es va plantejar l'estratègia d'enriquiment d’un oli d'oliva no només amb els seus propis fenols, sinó amb fenols complementaris d'herbes aromàtiques, concretament de farigola, amb la hipòtesi de que apart de proporcionar millores en l'estabilitat de l'oli i l'acceptació dels consumidors, també podria aportar beneficis addicionals per a la salut. Un cop desenvolupat l'oli d'oliva enriquit en fenols, es va avaluar la biodisponibilitat dels fenols mitjançant mètodes in vitro i in vivo, avaluant possibles interaccions o sinergies entre ambdues fonts fenòliques.
El enriquecimiento de aceite de oliva con sus propios fenoles se convierte en una estrategia interesante para aumentar y normalizar la ingesta diaria de hidroxitirosol sin aumentar el consumo calórico. Sin embargo, aceites con alto contenido fenólico tienen un sabor amargo que podría provocar rechazo entre los consumidores, y además sus altas dosis de hidroxitirosol podría tener una acción pro-oxidante. En esta tesis se planteó la estrategia de enriquecimiento de aceite de oliva no sólo con sus propios fenoles, sino con fenoles complementarios de hierbas aromáticas, concretamente tomillo, con la hipótesis de que no sólo podría proporcionar mejoras en la estabilidad del aceite y la aceptación de los consumidores, sino que podría aportar beneficios adicionales para la salud. Una vez desarrollado el aceite de oliva enriquecido se evaluó la biodisponibilidad de los fenoles mediante métodos in vitro e in vivo, evaluando posibles interacciones o sinergias entre ambas fuentes fenólicas.
The enrichment of olive oil with its own phenolic compounds becomes an interesting strategy to increase and standardize the daily intake of hydroxytyrosol without increasing the caloric intake. Concerning olive oils with high phenolic content, however, they have a bitter taste, which could promote a refusal among consumers, and contain high doses of hydroxytyrosol that could have a pro-oxidant action. In this context, the strategy of enriching olive oil not only with its own phenolics but also with complementary phenols from aromatic herbs was outlined in this thesis with the hypothesis that it could not only improve olive oil stability and consumers’ acceptation but also provide additional health benefits. In this thesis a phenol-enriched olive oil was developed using the aromatic herb of thyme, and the bioavailability of the phenolic compounds was assessed, evaluating possible interactions or synergies between both sources through in vitro and in vivo approaches.

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Bourne, Thomas Franklin. "Biodegradation of keratins and phenolic compounds". Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/25403.

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Semple, Kirk Taylor. "The biodegradation of phenols by a eukaryotic alga". Thesis, University of Newcastle Upon Tyne, 1994. http://hdl.handle.net/10443/374.

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Axenic cultures of Chiamydomonas ulvaensis [CCAP 11/58], Scenedesmus brasiliensis [CCAP 276/1 B] and Ochromonas danica [0CAP933/28] were screened for their ability to grow on and remove phenol from their incubation media. Neither C. ulvaensis nor S. brasiliensis removed the phenol substrate as rapidly as 0. danica which is a nutritionally versatile chrysophyte. 0. danica was found to grow on phenol and p-cresol as the sole C-source at concentrations up to 4mM in cultures grown in both photoheterotrophic and heterotrophic conditions. The alga would not grow on cresols or xylenols unless phenol was present. Oxygen uptake and turnover studies confirmed that the enzymes involved in phenolic catabolism were inducible and that the organism showed a decrease in activity resulting from the position and number of the methyl substituents on the aromatic ring. [U- 14C]Phenol was completely mineralised with some 65% of the 14C-label appearing as 14CO2, approximately 12% remaining in the aqueous medium and the rest accounted for in the biomass. Analysis of the biomass showed that 14C-label had been incorporated into the protein, nucleic acid and lipid fractions; phenol carbon is thus unequivocally assimilated by the alga. Phenol-grown cultures of 0. danica converted phenol to catechol which was further metabolised by the meta cleavage pathway. 2-Hydroxymuconic semialdehyde and pyruvate, characteristic products of meta cleavage, were found in incubations of catechol with cell-free extracts of phenol-grown cells together with the appropriate enzyme activities. This is , as far as I am aware, the first definitive identification of the meta cleavage pathway for aromatic ring degradation in a eukaryotic microorganism.

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Bifulco, Laura. "Development of electrochemical and microbial sensing systems for detection of phenolic compounds". Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269525.

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Khadambi, Tshiwela Norah. "Antimicrobial properties of phenolic compounds from sorghum". Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-03022007-164705.

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Alu'datt, Muhammad Hussein. "Phenolic compounds in oil-bearing plants and their interactions with oilseed protein isolates". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102950.

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Oil-bearing plants are important sources of edible oil and proteins; they have attracted attention recently because of their antioxidant, antimicrobial and anti-inflammatory properties. The objective of this work was to investigate the nature of phenolic compounds in oil-bearing plants and the effects of phenolic compounds on protein isolates from soybean and flaxseed. Proteins were isolated from full-fat and defatted soybean and flaxseed using sodium hydroxide extraction and isoelectric precipitation. Free phenolic compounds were extracted from the oil-bearing plants and protein isolates using methanol; for bound phenolic compounds the oil-bearing plants and proteins were subjected to basic and acidic hydrolysis followed by methanol extraction. Total free and bound phenolic compounds were determined by spectrophotometric analysis. Reversed phase-HPLC was used for separation of individual phenolic compounds, which were identified by mass spectrometry (MS). Molecular characteristics and biological properties of the protein isolates were studied using RP-HPLC, polyacrylamide gel electrophoresis (PAGE) and MS. Thermal and gelation properties of protein isolates were investigated using differential scanning calorimetry (DSC) and rheometry. Generally, bound phenolic compounds (20%-30% of total phenolic content) were higher in protein isolates from flaxseed than in protein isolates from soybean (10%-20% of total phenolic content). With flaxseed protein isolates, removal of phenolic compounds showed little effect on the electropherotic behavior of the proteins or the protein subunits. Native-PAGE. SDS-PAGE and RP-HPLC for the peptides profiles of hydrolyzed protein isolates from both full-fat and defatted soybean revealed the removal of free and bound phenolic compounds affect on the biological properties of protein isolates. Removal of free and bound phenolic compounds affected the thermal stability and gelation properties of protein isolates from flaxseed and soybean.

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Lu, Junhe. "Fundamental studies of the halogenation of phenolic compounds during water chlorination /". Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10197.

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Mafatle, Tsukutlane J. P. "Homogenous and heterogenous catalytic activity of metallophthalocyanines towards electrochemical detection of organic compounds". Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004974.

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Cysteine plays an important role in many biological and pharmaceutical systems. Therefore, in view of its importance, it is essential to find means of detecting it at the lowest possible levels. In this regard, electrochemical techniques have been found to be capable of detecting analytes even at micro levels. However, electrochemical determination of cysteine occurs at a very high potentials. These overpotentials makes quantitative analysis or detection of cysteine difficult at most conventional carbon electrodes. On platinum electrode, the oxidation of cysteine has been reported to occur in the potential range 0.7 to 1.45 V (vs NHE). Therefore, the object of this investigative study has been to find an active complex that could replace platinum and other expensive metals as electrodes. Such a complex should also be capable of reducing the potential at which the oxidation of cysteine occurs on carbon electrodes. As a result, this manuscript gives a full report on the investigative study of electrocatalytic activity of molybdenum phthalocyanine complexes towards detection of cysteine. Molybdenum phthalocyanine, OMo(OH)Pc, and its tetrasulfonated derivative, [OMo(OH)TSPc]⁴⁻ were successfully used to reduce the potential needed to initiate the oxidation of cysteine on carbon paste electrodes (CPE). The oxidation of cysteine on CPE modified with [OMo(OH)Pc]⁴⁻ was found to occur at 0.29 V (vs Ag/AgCl), and in the presence of [OMo(OH)TSPc]⁴⁻ species in solution the oxidation occurred at 0.33 V (vs Ag/AgCl). Molybdenum, in the oxidation states of Mo(IV), Mo(V) and Mo(VI), is found in biological systems as an essential trace element, participating in a number of enzymatic reactions, where it is believed to be coordinated to sulphur-containing ligands in many molybdenum enzymes. This therefore explains why molybdenum phthalocyanines were employed in electroanalytical detection of sulphur containing amino acid, cysteine. Electrochemical methods have also been successfully used in detection of environmental pollutants such as phenolic compounds. Phenolic compounds are oxidised at readily accessible potentials. However, like cysteine, there are problems associated with the electrochemical detection of these important environmental pollutants. Their electrooxidation is known to form dimeric and/or polymeric oxidation products which adsorb onto the electrode surface, thus -videactivating it. Therefore, to address this problem, cobalt phthalocyanine (CoPc) and its tetrasulfonated derivative, [CoTSPc]⁴⁻ were employed in electrocatalytic detection of phenolic compounds. These complexes were found to increase the anodic peak currents for the oxidation of o-cresol, m-cresol, p-cresol, phenol, 2-chlorophenol and 4-chlorophenol. In addition, CoPc deposited onto the glassy carbon electrode improved the stability of the electrode, by reducing electrode poisoning caused by the electrooxidation products of the mentioned phenolic compounds. The potential at which the oxidation occurred and the current response of individual phenolic compounds depended on the degree of substitution and the type of substituent on the phenol molecule. In general, the current response was found to be lower for chlorinated phenols compared with the cresols and phenol. To establish the role of the central metal in the catalytic process, comparison of the electrocatalytic activity of some of the first row transition metal phthalocyanines, for the detection of mono-substituted phenolic compounds, showed the following trend: Co⁽¹¹⁾ > Mn⁽¹¹⁾ > Fe⁽¹¹⁾Pc > Ni⁽¹¹⁾Pc > Cu⁽¹¹⁾Pc > H₂Pc > Zn⁽¹¹⁾Pc > Bare GCE. A report is also given on electrocatalysis using [CoTSPc]⁴⁻ electrochemically deposited on the glassy carbon electrode. This was also found to enhance the anodic peak currents for the oxidation of all phenolic compounds. A report on the effects of scan rate, operating potential, analyte concentration and other variables is also given.

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SIAHAAN, TERUNA JAYA. "PREPARATIONS AND REACTIONS OF CRESOL DIANIONS AND DIMETHYLPHENOL TRIANIONS (ANISOLE, ALKYL PHENOL, CYCLOPHANE)". Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183846.

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With n-BuLi/t-BuOK (Lochmann's base), protons are removed from the hydroxyl and methyl groups of cresols to give cresol dianions in yields of 85% (o), 95% (m), and 40% (p). These dianions react with alkyl halides, MeSiCl, Bu₃Sn Cl, CO₂, and oxidizing agents at carbon only, and with dialkyl sulfates at both carbon and oxygen. Thus phenol derivatives bearing primary alkyl groups can be prepared from the corresponding methylphenol via cresol dianions. Dimethylphenol trianions were prepared with Lochmann's base from all six isomers of dimethylphenol. 3,5-Dimethylphenol trianion was prepared in the best yield (80%); 2,3-, 2,4-, 2,5-, 2,6-, and 3,4-dimethylphenol trianions were prepared in 19.5%, 19%, 52%, 36%, and 44% yields, respectively. The common side products were dianions and tetraanions (in the latter, the fourth proton was usually pulled from the ring ortho to oxygen). These trianions were reacted with dimethyl sulfate to give anisole derivatives. 3,5-Dimethoxytoluene monoanion was reacted with n-BuBr to give a mixture of O,O'-dimethylolivetol (40%) and 4-butyl-3,5-dimethoxytoluene (34%).

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Más fuentes

Libros sobre el tema "Phenols compounds"

Juha, Kallas y Lappeenrannan teknillinen korkeakoulu, eds. Treatment technology of wastewater containing phenols and phenolic compounds. Lappeenranta: Lappeenranta University of Technology, 1992.

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Corporation, Syracuse Research, Clement International Corporation y United States. Agency for Toxic Substances and Disease Registry, eds. Toxicological profile for nitrophenols: 2-nitrophenol, 4-nitrophenol. [Atlanta, Ga.?]: The Agency, 1992.

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1951-, Shahidi Fereidoon, Ho Chi-Tang 1944- y American Chemical Society. Division of Agricultural and Food Chemistry, eds. Phenolic compounds in foods and natural health products. Washington, DC: American Chemical Society, 2005.

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Aura, Anna-Marja. In vitro digestion models for dietary phenolic compounds. [Espoo, Finland]: VTT Technical Research Centre of Finland, 2005.

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Gmehling, Jürgen. Vapor-liquid equilibrium data collection: Organic hydroxy compounds : alcohols and phenols : supplement 4. Frankfurt-am-Main: DECHEMA, 1990.

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Palo, R. Thomas. Phenols as defensive compounds in birch (Betula spp.): Implications for digestion and metabolism in browsing mammals. Uppsala: Sveriges lantbruksuniversitet, 1987.

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G, Fraga Cesar, ed. Phenolic compounds of plant origin and human health: Biochemistry behind their nutritional and pharmacological value. Hoboken, N.J: Wiley, 2009.

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Levén, Lotta. Anaerobic digestion at mesophilic and thermophilic temperature: With emphasis on degradation of phenols and structures of microbial communities. Uppsala: Swedish University of Agricultural Sciences, 2006.

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Wilfred, Vermerris. Phenolic compound biochemistry. Dordrecht: Springer, 2006.

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Wilfred, Vermerris. Phenolic compound biochemistry. Dordrecht: Springer, 2006.

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Más fuentes

Capítulos de libros sobre el tema "Phenols compounds"

Trujillo-Rodríguez, María J., Verónica Pino y Juan H. Ayala. "Extraction of Alcohols, Phenols, and Aromatic Compounds with ABS". En Green Chemistry and Sustainable Technology, 135–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-52875-4_7.

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Herminghaus, S., S. Arendt, S. Gubatz, M. Rittscher y R. Wiermann. "Aspects of Sporopollenin Biosynthesis: Phenols as Integrated Compounds of the Biopolymer". En Sexual Reproduction in Higher Plants, 169–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73271-3_27.

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Malhotra, Milan, Divya Gupta, Jeetendra Sahani y Sanjay Singh. "Microbial Degradation of Phenol and Phenolic Compounds". En Recent Advances in Microbial Degradation, 297–312. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0518-5_11.

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Knop, Andre y Louis A. Pilato. "Molding Compounds". En Phenolic Resins, 196–212. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-662-02429-4_12.

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Silva, João J. R. Fraústo, M. Fátima C. Guedes Silva, José Armando L. Silva y Armando J. L. Pombeiro. "Redox Properties of the Amavadine Models [V(HIDA)2]2- and [V(HIDPA)2]2- and Their Electroinduced Reactivity Towards Activated-Thiols and -Phenols". En Molecular Electrochemistry of Inorganic, Bioinorganic and Organometallic Compounds, 411–15. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1628-2_37.

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Mello, Beatriz. "Phenolic Compound". En Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40872-4_458-4.

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Koizumi, Koji, Ted Charles y Hendrik De Keyser. "Phenolic Molding Compounds". En Phenolic Resins: A Century of Progress, 383–437. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-04714-5_16.

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Shahidi, Fereidoon. "Phenolic Compounds ofBrassicaOilseeds". En ACS Symposium Series, 130–42. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0506.ch010.

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Chowdhary, Vibhakar, Sheena Alooparampil, Rohan V. Pandya y Jigna G. Tank. "Physiological Function of Phenolic Compounds in Plant Defense System". En Phenolic Compounds - Chemistry, Synthesis, Diversity, Non-Conventional Industrial, Pharmaceutical and Therapeutic Applications. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101131.

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Plants respond to various abiotic and biotic stress conditions through accumulation of phenolic compounds. The specificity of these phenolic compounds accumulation depends on the type of stress condition and the response of plant species. Light stress induces biosynthesis of phenolic acids and flavonoids in plants. Temperature stress initially induces biosynthesis of osmoprotective compounds and then later stimulates synthesis of antioxidant enzymes and antioxidant compounds such as flavonoids, tannins and phenolic acids in plant cells. Salinity causes oxidative stress in plants by inducing production of reactive oxygen species. To resist against oxidative stress plants produce polyphenols, flavonoids, anthocyanins, phenolic acids and phenolic terpenes. Plants biosynthesize phenols and flavonoids during heavy metal stress.to scavenge the harmful reactive oxygen species and to detoxify the hydrogen peroxide. Plants accumulate phenols at the infection sites to slow down the growth of microbial pathogens and restrict them at infected site. Plants also accumulates salicylic acid and H2O2 at the infection site to induce the systemic acquired resistance (SAR) against microbial pathogens. Plants accumulate phenolic compounds which act as inhibitor or toxicant to harmful nematodes, insects and herbivores. Hence, phenols regulate crucial physiological functions in plants to resist against different stress conditions.

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Dhatwalia, Vinod K. y Manisha Nanda. "Biodegradation of Phenol". En Biotechnology, 1149–65. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8903-7.ch045.

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Aromatic compounds are widely distributed in nature. Free phenols are frequently liberated as metabolic intermediates during the degradation of plant materials. In recent years the natural supply of phenolic substances has been greatly increased due to the release of industrial byproducts into the environment. Phenolic compounds are hazardous pollutants that are toxic at relatively low concentration. Effluents from petrochemical, textile and coal industries contain phenolic compounds in very high concentration; therefore there is a necessity to remove phenolic compounds from the environment. Microorganisms capable of degrading phenol are common and include both aerobes and anaerobes. The use of microbial catalysts in the biodegradation of organic compounds has advanced significantly during the past three decades. The efficiency of biodegradation of organic compounds is influenced by the type of the organic pollutant, the nature of the organism, the enzyme involved, the mechanism of degradation and the nature of the influencing factors.

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Actas de conferencias sobre el tema "Phenols compounds"

Šaćirović, Sabina, Andrija Ćirić, Mališa Antić y Zoran Marković. "HPLC ANALYSIS OF PHENOLS OF SLOVENIAN RED WINES: CABERNET SAUVIGNON AND MERLOT". En 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.165s.

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In this study, HPLC-DAD rapid analysis of phenols in wine samples was performed. The recording was performed at different wavelengths: phenolic acid (254nm), flavan-3-ols and stilbene (280nm), flavonoids (340nm) and anthocyanins (520nm). In selected wines, the concentrations of the following compounds were determined and expressed in mg/l of wine. The isolated derivatives were: hydroxybenzoic acids, derivatives of caffeic, ferulic, syringic, and vanillic acids, catechin (flavanol), rutin, myricetin and quercetin (flavonols), and the stilbene derivative-resveratrol. The properties and quantities of phenolic compounds in organic wines were investigated. The results show the content of phenolic compounds in organic wines do not differ qualitatively and quantitatively from those in conventional wines. Wine samples have shown good antioxidative activity according to both DPPH and FRAP analysis, which indicates the good antioxidative potential and high antioxidant concentration in tested wines. Cabernet Sauvignon wines have shown better radical scavenging activity than Merlot, especially when the DPPH test was considered.

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Pavlović, M., Z. Simić y Gorica Đelić. "DETERMINATION OF HEAVY METALS AND SECONDARY METABOLITES OF „PEUCEDANUM OREOSELINUM“ (APIACEAE)". En 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.206p.

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The total quantity of metals (Mg, Ca, Ni, Fe, Mn, Zn, Cu) in soil samples and in sixteen different extracts from plant parts of Peucedanum oreoselinum (L.) Moench as well as the content of total phenols and flavonoids in plant extracts was determined. The contents of metals were determined by the atomic absorption spectrometer. Based on the average values of the metal concentration in the soil, they could be arranged in the following sequence: Fe > Ca > Mg > Mn > Zn > Cu > Ni. Soil concentrations of all tested metals were lower than the maximum allowed concentration. The results demonstrated that the analyzed plant extracts contained higher quantities of Ni and Ca. Although the studied species accumulate analyzed metals in different quantities, they are not hyperaccumulators of these metals. Total phenols were determined using Folin-Ciocalteu reagent and their amounts ranged from 1.94 to P. oreoselinum, hyperaccumulation, phenols, flavonoids32.38 mg GA/g. The amounts of flavonoids in plant extracts were in range from 0.69 to 25.83 mg RU/g. We examined the correlation of metals and the phenolic compounds content in the extracts. According to our results the use P. oreoselinum for tea preparation is safe to a great extent for people, because in spite of the determined metal absorption by plant organs, the tea does not contain dangerous quantity of heavy metals. Also, it is suitable for the preparation of teas and herbal extracts due to minimal content of toxic metal (Ni), phenols and flavonoids.

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Zhao, Hefei y Selina Wang. "Isolation and purification phenolic compounds in California olive pomace by pilot-scale C18 gel chromatography". En 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/hkjz6249.

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According to the Food and Agriculture Organization, the United States (mainly in California) produced 151,950 tons of olives in 2019, which resulted in a large amount of pomace waste. While many researchers focused on crude extraction and macroporous resin purification from European olive pomace on an analytical scale, few studies have been conducted to isolate fractions of US olive pomase (OP) by pilot-scale C18 chromatography. Hexane defatted Arbequina California OP was extracted by water, and the extract was loaded to a pilot-scale chromatography column with 262.5 mL C18 gel, and the elute syrup (ES) was collected. Desorptions were applied by 1 L of acidified water (AW), 35% methanol (35M) and 70% methanol (70M), respectively. The fractions were concentrated then freeze-dried. Total phenol contents (TPC) were measured by Folin-Ciocalteu assay. Individual phenols were determined by HPLC-DAD. Results showed that the TPC of the fractions of ES, AW, 35M and 70M were 2.88, 29.39, 170.56 and 235.96 mg gallic acid equivalents/g, respectively. Heatmap cluster analysis showed that ES and AW fractions had similar phenol profiles with hydroxytyrosol and tyrosol-glucoside; and 35M had hydroxytyrosol-glucoside, hydroxytyrosol, tyrosol-glucoside, 4-hydroxyphenylacetic acid (4-HPA), verbascoside and oleuropein; 70M contained hydroxytyrosol, tyrosol-glucoside, tyrosol, but generally had more nonpolar compounds such as verbascoside, rutin and oleuropein. Very interestingly, the 3,4-DHPEA-EDA in water extract at 31.43 min disappeared in 35M and 70M fractions, meanwhile a new peak at 29.25 min showed up which could be a new compound derived from 3,4-DHPEA-EDA possibly because of the acidified process. This study could be the first-ever report of phenol profile of pilot-scale C18 fractions of the US OP. This new data on the chemical compositions of the OP C18 fractions provides practical knowledge for the valorization and industrial food applications of the US olive wastes.

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Vieitez Osorio, Ignacio, Adriana Gambaro, Cecilia Dauber, Elena Ibanez, Laura Gonzalez y Tatiana Carreras. "Supercritical extracts from olive leaves as natural antioxidants: extraction optimization, characterization and evaluation". En 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/dtog7326.

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Olive leaves (OL) are considered a potential source of bioactive compounds mainly due to its high content of polyphenols, widely known as natural antioxidants. The objective of this study was to optimize supercritical fluid extraction conditions from OL in order to obtain natural extracts with high antioxidant activity. OL (belong to the Arbequina cultivar) were collected from a local producer (Uruguay) and subjected to a drying and milling (1 mm particle size) pre-treatment. Supercritical fluid extractions were carried out using a laboratory-built system equipped with a 25 mL stainless steel vessel filled with 10 g of OL. A total of 10 extractions were carried out following a Central Composite Design in which the two independent variables considered were: extraction temperature (40–60 °C) and extraction pressure (150-350 bar). In all cases, extraction solvent was CO2 with 10% of ethanol as modifier. A constant flow rate of 0.5 L/min CO2 was set and each run was finished when 100 L of CO2 were measured in the flow totalizer. Extraction yield (% wt), total phenolic content (Folin-Ciocalteau) and antioxidant activity (ABTS+. assay) of the extracts were considered as response variables. Extraction yield was positively correlated with temperature and pressure, while total phenolic content and antioxidant activity were negatively correlated with temperature. Phenolic content of the extracts varied from 22.9 to 53.6 mg GAE/g. For the extract obtained at optimal conditions, the identification of individual polyphenols was performed by RP/HPLC-Q-TOF MS/MS, being phenolic acids, simple phenols and secoiridoids the most abundant compounds. Finally, oxidative stability of canola oil with or without the incorporation of 250 ppm of some extracts was assessed during five weeks of storage at 60°C. Peroxide, K232, K270, and Rancimat values, besides tocopherol content were determined. Results obtained reinforce the use of supercritical fluid technology to obtain antioxidants compounds from natural sources.

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"Identification of Phenols and Triterpenoids Compounds in Michelia champaca for Treating Covid 19 Symptom by in Silico". En 1st Bioinformatics and Biodiversity Conference. Galaxy Science, 2021. http://dx.doi.org/10.11594/nstp.2021.0706.

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Srzednicki, George, Qixin Li y Robert H. Driscoll. "Effects of different drying conditions on curcumin concentration in turmeric". En 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7247.

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Turmeric (Curcuma longa), belongs to Zingiberaceae family. The rhizomes contain bioactive compounds of the curcuminoids group (natural phenols). They are used in food and pharmaceutical industry. The aim of this research was to acquire dried turmeric with high total curcumin content. In this study, optimum turmeric drying conditions and new extraction techniques were explored. Fresh turmeric samples were subjected to constant vs changing drying air temperatures and pre-treatment (blanching). Changing drying air temperature and use of non-blanched turmeric slices resulted in the highest concentration of curcumin. Ultrasonic extraction instead of soxhlet extraction improved the extraction efficiency and decreased extraction time. Keywords: Turmeric, Curcumin; Drying; Blanching; Extraction

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Kandassamy, K., E. Natarajan y S. Renganarayanan. "Producer Gas Cleaning Techniques". En 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-061.

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This paper reviews various producer gas cleaning techniques developed/ applied in different biomass gasification processes. It investigates various methods for the removal of particulate matter and tar emissions from producer gas generated by various types of gasifiers. The various tar measurement protocols are inconsistent on the definition of tar and particulate matters. The producer gas if used for power generation using IC engines should be less than 50 mg/Nm3, and in the case of gas turbines a minimum particulate matter concentration of 10 ppm (weight) is needed. To control tars and particulates, various insitu (catalytic tar cracking using Dolomite/Nickel, partial oxidation, high temperature tar cracking, biomass selection, two stage gasification) and post gasification treatments (sand bed filter, wash tower, venturi scrubber, rotational atomizer, electrostatic precipitator, fabric filter, fixed bed tar adsorber, catalytic tar cracker, ceramic filter, cyclones etc) are used. In the cleaning train, collection efficiencies decrease drastically as particulate sizes fall below 1.5 μm. Heavy tar and alkali metals cause engine cylinder deposition and high temperature corrosion of turbine blades respectively. The selection of suitable biomass can improve the quality of gas. Nearly every biomass has a high percentage (60–80%) of Tar Forming Particles (PTFV). Tar is a general nomenclature for a group of compounds like phenols, Poly Aromatic Hydrocarbons (PAH), high Molecular Organic Compounds, Water-soluble organic compounds and ash particles agglomerated with organic compounds. It is easier to remove 90% particulate matter than to achieve 90% tar reduction as they form stable aerosols. A combination of insitu and post gasification treatments is necessary to condition the fuel gas for various power generating equipments. Hence, the analysis of various gas cleaning methods are important for applying them in suitable systems.

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Burlakovs, Juris, Ruta Ozola-Davidane y Maris Klavins. "INNOVATIVE COMPOSITE SORBENTS FOR ORGANIC AND INORGANIC POLLUTANTS REMOVAL FROM AQUEOUS SOLUTIONS IN LANDFILL LEACHATES". En International Scientific Conference “EcoBalt 2021”. University of Latvia Press, 2021. http://dx.doi.org/10.22364/isceb.2021.01.

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The study reveals the development of appropriate innovative sorbents based on clay material for arsenic and p-nitrophenol sorption using iron oxy-hydroxide and surfactant modification. Natural and manufactured clay were chosen for comparison of modification efficiency to obtain the best sorption results for As (V) and p-nitrophenol. Obtained results indicate that modification of clay with iron compounds and various surfactants significantly improve the sorption capacity of newly developed materials used for sorption of inorganic and organic compounds from aqueous solutions in landfill leachates.Natural clay minerals have received a lot of attention as potential sorbents, because of their abundance, cost-effectiveness, high sorption and ion-exchange properties [1]. Clay minerals can be modified using different approaches to obtain innovative materials for application as sorbents in the removal of inorganic and organic pollutants from leachates, wastewater, groundwater and soil [2, 3]. Modification with surfactants improves hydrophobization needed if interaction with low polarity organic molecules is necessary, but chemical modification with inorganic species, e.g., hydrated iron supports the physical improvement of sorption and ion exchange process in order to benefit the treatment of media from inorganic pollutants [4]. Materials achieved better properties for specific remedial applications regarding heavy metals and metalloids, prepared organoclays from hydrophilic montmorillonite by intercalating cationic or nonionic surfactants can interact with organic molecules of differing polarity and serve as immobilizers for organic molecules and toxicants, e.g., phenols and NOCs. Further studies will reveal improved properties to benefit landfill leachate treatment, wastewater engineering and environmental remediation industries.

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Lei, Hanwu, Shoujie Ren, James Julson, Lu Wang, Quan Bu y Roger Ruan. "Microwave Torrefaction of Corn Stover and Tech-Economic Analysis". En ASME 2011 International Manufacturing Science and Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/msec2011-50230.

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Microwave torrefaction of corn stover with particle size of 4 mm was investigated and the effects of reaction temperature and time on the yields of volatile, bio-oil and torrefied biomass were determined. The response surface analysis of the central composite design (CCD) showed that the yields of volatile, bio-oil and torrefied biomass were significantly affected by the reaction temperature and time. Three linear models were developed to predict the yields of conversion products as a function of temperature and time. A first order reaction kinetics was also developed to model the corn stover torrefaction. Ph values of torrefaction bio-oils ranged from 2.3 to 2.76 which were similar to those of bio-oils from biomass pyrolysis. GC/MS analysis for torrefaction bio-oils showed that the organic acid was about 2.16% to 12.00%. The torrefaction bio-oils also contain valuable chemical compounds such as phenols, furan derivatives and aliphatic hydrocarbons determined by a GC/MS. There are no aromatic compounds and polycyclic aromatic hydrocarbons (PAHs) detected in the torrefaction bio-oils. The torrefaction biogas was mainly consisted of ch4, c2h6, c3h8, which was about 56 wt% of the total bio-gas. The biogas can be used for chemical synthesis or electricity generation. The heating values of torrefied biomass were from 18.64–22.22 MJ/kg depending on the process conditions. The heating values of torrefied biomass were significantly greater than those of raw biomass and similar to those of coals. The energy yields of torrefied biomass from 87.03–97.87% implied that most energy was retained in the torrefied biomass. Economic analysis indicated that the biomass microwave torrefaction plant located in a farm is profitable.

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Veronda, Brenda y Matthew Dingens. "The State of Permanganate With Relation to In Situ Chemical Oxidation". En The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7002.

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In Situ Chemical Oxidation (ISCO) with permanganate had its beginnings over 10 years ago. Since that time, many sites have been successfully treated for organic compounds including chlorinated ethenes (perchloroethylene, trichloroethylene, etc.) phenols, explosives such as RDX, and many other organics. The successful application of ISCO with permanganate requires the integration of many site-specific factors into the remedial design. ISCO with permanganate is an effective technology, not only for its oxidative properties and persistence, but also for its application flexibility to remediate soil and groundwater. The merits of any type of treatment technology can be assessed in terms of effectiveness, ease of use, reaction rate, and cost. The use of permanganate for in-situ chemical oxidation results in the complete mineralization of TCE and PCE and can result in treatment levels below detection limits. Permanganate is a single component oxidizer, which is easily handled, mixed and distributed to the subsurface. Permanganate is also inexpensive to design and implement as compared to other technologies. This presentation will provide a general overview of the application and safety aspects of ISCO with permanganate. This paper will discuss the advantages and limitations of this technology, typical cost ranges, site evaluation and application technologies.

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Informes sobre el tema "Phenols compounds"

Cerquido, Ana Sofia, Martin Vojtek, Rita Ribeiro-Oliveira, Olga Viegas, Joana Beatriz Sousa, Isabel M. P. L. V. O. Ferreira y Carmen Diniz. Unravelling potential health‐beneficial properties of Corema album phenolic compounds: a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, agosto de 2022. http://dx.doi.org/10.37766/inplasy2022.8.0022.

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Review question / Objective: A systematic review of the literature was carried out to summarize the phenolic compounds and bioactive properties identified in C. album berries and leaves and search for research gaps on this topic. Condition being studied: Summarize the phenolic compound's composition of Corema album berries and leaves assessed by advanced analytical methods and assessment of their bioactive properties. Information sources: Three databases PubMed, SCOPUS, and Web of Science as information sources. The following keywords were used: (“Corema album” AND (berries OR leaves)). Contact with authors or grey literature was not used as information source.

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Kanner, Joseph, Edwin Frankel, Stella Harel y Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, enero de 1995. http://dx.doi.org/10.32747/1995.7568767.bard.

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Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.

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Grant, T. M. y C. J. King. Irreversible adsorption of phenolic compounds by activated carbons. Office of Scientific and Technical Information (OSTI), diciembre de 1988. http://dx.doi.org/10.2172/6416993.

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Nelson, Nicholas. Catalytic upgrading of phenolic compounds using ceria-based materials. Office of Scientific and Technical Information (OSTI), noviembre de 2016. http://dx.doi.org/10.2172/1593322.

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Ozkan, Gursel. Phenolic Compounds, Organic Acids, Vitamin C and Antioxidant Capacity in Prunus spinosa L. Fruits. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, febrero de 2019. http://dx.doi.org/10.7546/crabs.2019.02.17.

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Choudhary, Ruplal, Victor Rodov, Punit Kohli, John D. Haddock y Samir Droby. Antimicrobial and antioxidant functionalized nanoparticles for enhancing food safety and quality: proof of concept. United States Department of Agriculture, septiembre de 2012. http://dx.doi.org/10.32747/2012.7597912.bard.

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General concept. The reported 1-year study tested the feasibility ofpreparing antimicrobial and antioxidant nanoparticlesfunctionalized with natural phenolic compounds, as a first step to reach the ultimate goal - improving safely and quality of foods by developing novel antimicrobial and antioxidant food-contacting materials. The secondary objectives of the study were (a) selecting the most promising phenoliccompounds, (b) building nanoparticles with the selected phenolicgrafted on their Surface, and (c) testing antimicrobial and antioxidant properties of these particles. The study was expected to provide a " go/no go" decision as concerning the prospects of phenolic- bound nanoparticles as antimicrobial and antioxidant agents. Results. In course of the feasibility study, curucminwas chosen as the most promising phenoliccompound due to its high antibacterial activity exceeding other tested compounds by at leas one order of magnitude. Lipsome-typephospholipid/polydiacetylene(PDA) nanoparticlesfunctionalizedwith curcuminwere successfully built. The pitfall of limited curcumin amount that could be covalently bound to theparticle surface was circumvented by inclusion of curcunun in the liposome body. It was suggested onthe basis of fluorescence spectroscopy that curcuminwas bound by hydrophobic forces in the bi1ayer periphery of the Liposomesand therefore mightexert a contact effect on microorganisms. The curcumin functionalizednanoparticles(CFN) were shown to have a strong bactericidal activity towards both Gram-negative (E. coli) and Gram-positive (B. ce,·e11s) bacteria, but only limited effect against yeast. Furthermore, beyond the originallyplanned objectives, preliminary trials showed that CFN could be bound to silanized glass surface rendering aנבtiנnicrobial activity to the glass. Tnaddition, the particles showed antioxidantcapacity. Tberefore, it ,vas co11cluded tlוattlוeaims of tlוefeasibility study bad been successfully reached an

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Koziel, Jacek, Yael Laor, Jeffrey Zimmerman, Robert Armon, Steven Hoff y Uzi Ravid. Simultaneous Treatment of Odorants and Pathogens Emitted from Confined Animal Feeding Operations (CAFOs) by Advanced Oxidation Technologies. United States Department of Agriculture, enero de 2009. http://dx.doi.org/10.32747/2009.7592646.bard.

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A feasibility study was conducted, aiming to explore the potential effectiveness of UV/TiO2/O3 photooxidation technologies for simultaneous treatment of odorant and pathogen emissions from livestock and poultry operations. Several key parameters were tested in laboratory (US) and semi-pilot (Israel) scale conditions including: the effects of light energy dose (treatment time and light intensity), relative humidity and air temperature, UV wavelength, presence of photocatalyst (TiO2) and the presence of ozone. Removal and conversion of odor, target gases (sulfur-containing volatile organic compounds S-VOCs, volatile fatty acids (VFAs), phenolics, and ammonia), and airborne pathogens was tested. Up to 100% removal (below method detection level) of S-VOCs, VFAs, and phenolics, the overall odor, and up to 64.5% of ammonia was achieved with optimized treatment. Treatments involving deep UV band (185 nm) and photocatalyst (TiO2) were more efficient in removal/conversion of odorous gases and odor. The estimate of the operational cost of treatment was based on measured emissions of several odorous VOCs from full scale, commercial swine farm ranges from $0.15 to $0.59 per finisher pig. This figure represents significantly lower cost compared with the cost of biofiltration or air scrubbing.

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Yu, S. K.-T., R. P. Vrana y J. B. Green. Retention indices, relative response factors, and mass spectra of trifluoroacetate esters of phenolic compounds determined by capillary GC/MS: Topical report. Office of Scientific and Technical Information (OSTI), abril de 1989. http://dx.doi.org/10.2172/6421637.

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Bostock, Richard M., Dov Prusky y Martin Dickman. Redox Climate in Quiescence and Pathogenicity of Postharvest Fungal Pathogens. United States Department of Agriculture, mayo de 2003. http://dx.doi.org/10.32747/2003.7586466.bard.

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Monilinia fructicola causes brown rot blossom blight and fruit rot in stone fruits. Immature fruit are highly resistant to brown rot but can become infected. These infections typically remain superficial and quiescent until they become active upon maturation of the fruit. High levels of chlorogenic acid (CGA) and related compounds occur in the peel of immature fruit but these levels decline during ripening. CGA inhibits cutinase expression, a putative virulence factor, with little or no effect on spore germination or hyphal growth. To better understand the regulation of cutinase expression by fruit phenolics, we examined the effect of CGA, caffeic acid (CA) and related compounds on the redox potential of the growth medium and intracellular glutathione (GSH) levels. The presence of CA in the medium initially lowered the electrochemical redox potential of the medium, increased GSH levels and inhibited cutinase expression. Conidia germinated in the presence of CA, CGA, or GSH produced fewer appressoria and had elongated germ tubes compared to the controls. These results suggest that host redox compounds can regulate fungal infectivity. In order to genetically manipulate this fungus, a transformation system using Agrobacterium was developed. The binary transformation vector, pPTGFPH, was constructed from the plasmid pCT74, carrying green fluorescent protein (GFP) driven by the ToxA promoter of Pyrenophora tritici-repentis and hygromycin B phosphotransferase (hph) under control of the trpC promoter of from Aspergillus nidulans, and the binary vector pCB403.2, carrying neomycin phosphotransferase (nptII) between the T-DNA borders. Macroconidia of M. fructicola were coincubated with A. tumefaciens strain LBA 4404(pPTGFPH) on media containing acetosyringone for two days. Hygromycin- and G418-resistant M. fructicola transformants were selected while inhibiting A. tumefaciens with cefotaxime. Transformants expressing GFP fluoresced brightly, and were formed with high efficiency and frequency of T-DNA integration frequency. The use of these transformants for in situ studies on stone fruit tissues is discussed.

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Naim, Michael, Gary R. Takeoka, Haim D. Rabinowitch y Ron G. Buttery. Identification of Impact Aroma Compounds in Tomato: Implications to New Hybrids with Improved Acceptance through Sensory, Chemical, Breeding and Agrotechnical Techniques. United States Department of Agriculture, octubre de 2002. http://dx.doi.org/10.32747/2002.7585204.bard.

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The tomato, a profitable vegetable crop in both the USA and Israel, has benefited significantly from intensive breeding efforts in both countries, and elsewhere (esp. Holland). : Modem hybrids are highly prolific and resistant to a variety of major pests. They produce attractive, firm fruit for both processing and fresh-marketing. In all cases, however, reduction in flavor and aroma have occurred concomitantly with the increase in yield. Sugars-acids ratio dominate fruit taste, whereas aroma volatiles (potent at minute ppb and ppt levels) contribute to the total characteristic tomato flavor. An increase in sugars (1-2%) contributes significantly to tomato fruit taste. However, because of energy reasons, an increase in fruit sugars is immediately compensated for by a decrease in yield. Our main objectives were to: (a) pinpoint and identify the major impact aroma components of fresh tomato; (b) study the genetic and environmental effects on fruit aroma; (c) determine precursors of appealing (flavors) and repelling (off-flavors) aroma compounds in tomato. Addition of saturated salts blocked all enzymatic activities prior to isolation of volatiles by dynamic and static headspace, using solvent assisted flavor evaporation (SAFE) and solid phase micro-extraction (SPME) from highly favored (FA-612 and FA-624) and less preferred (R 144 and R 175) tomato genotypes. Impact aroma components were determined by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC- MS) and aroma extract dilution analysis (AEDA). The potent odorant (Z)-1,5-octadien-3-one, was identified for the first time in fresh tomato. From the ca. 400 volatile compounds in the headspace of fresh tomato, the following compounds are proposed to be impact aroma compounds: (Z)-3-hexenal, hexanal, 1-penten-3-one, 2-phenylethanol, (E)-2-hexenal, phenyl acetaldehyde, b-ionone, b-damascenone, 4-hydroxy-2,5-dimethyl-3-(2H)-furanone (FuraneolR), (Z)-l,5-octadien-3-one, methional, 1-octen-3-one, guaiacol, (E,E)- and (E,Z)- 2,4-decadienal and trans- and cis-4,5-EPOXY -(E)-2-decenal. This confirms the initial hypothesis that only a small number of volatiles actually contribute to the sensation of fruit aroma. Tomato matrix significantly affected the volatility of certain impact aroma components and thus led to the conclusion that direct analysis of molecules in the headspace . may best represent access of tomato volatiles to the olfactory receptors. Significant differences in certain odorants were found between preferred and less-preferred cultivars. Higher consumer preference was correlated with higher concentrations of the following odorants: l-penten-3-one, (Z)-3-hexenal, (E,E)- and (E,Z)-2,4-decadienal and especially Furaneol, whereas lower consumer preference was associated with higher concentrations of methional, 3-methylbutyric acid, phenylacetaldehyde, 2-phenylethanol, and 2-isobutylthiazole. Among environmental factors (salinity, N source, growth temperature), temperature had significant effects on the content of selected aroma compounds (e.g., 3-methylbutanal, 1- penten-3-one, hexanal, (Z)-3-hexenal, (E)-2-hexenal, 2-isobutylthiazole, 6-methyl-5-hepten- 2-one, 1-octen-3-one, methional, 2-phenylethanal, phenyl acetaldehyde, and eugenol) in fresh tomatoes. Salt stress (20 mM NaCl) increased the content of odorants such as (Z)-3-hexenal, 2-phenylethanol and 3-methylbutanal in the R-144 cultivar whereas salinity had minor effects on 1-pentene-3-one, 2-isobutylthiazole and b-ionone. This fundamental knowledge obtained by comprehensive investigation, using modem chemical, sensory and agrotechnical methodology will assist future attempts to genetically modify the concentrations of key odorants in fresh tomatoes, and thus keep the tomato production of Israel and the USA competitive on the world market.

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